JP2024066518A - Salt, acid generator, resist composition and method for producing resist pattern - Google Patents

Abstract

The present invention relates to a resist pattern having good line edge roughness (LER). The present invention relates to an acid generator containing a salt represented by formula (I). JPEG2024066518000226.jpg57170 [Selected Figure] None

Description

The present invention relates to a salt, an acid generator, a resist composition, and a method for producing a resist pattern.

Patent Document 1 describes a salt represented by the following formula and a resist composition containing the salt as an acid generator.

JP 2021-178816 A

There is a demand for resist compositions that can form resist patterns with good line edge roughness (LER).

The present invention includes the following inventions.
[Invention 1]
An acid generator comprising a salt represented by formula (I):

[In formula (I),
X represents a sulfur atom or an iodine atom.
m10 represents 0 or 1, and when X is a sulfur atom, m10 is 1, and when X is an iodine atom, m10 is 0.

Ar ¹ , Ar ² and Ar ³ each independently represent an aromatic hydrocarbon group having 10 to 14 carbon atoms.
R ¹ , R ² and R ³ each independently represent *-O-R ¹⁰ , *-O-CO-R ¹⁰ , *-O-CO-O-R ¹⁰ or *-OL ¹⁰ -CO-O-R ¹⁰ , where * represents a bonding site to Ar ¹ , Ar ² or Ar ³ , respectively.

L ¹⁰ represents an alkanediyl group having 1 to 6 carbon atoms.
R ¹⁰ represents a group having a cyclic carbonate structure.
R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represent a halogen atom, a haloalkyl group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 36 carbon atoms, the hydrocarbon group may have a substituent, and the -CH ₂ - contained in the haloalkyl group and the hydrocarbon group may be replaced with -O-, -S-, -CO-, -SO- or -SO ₂ -. In addition, when X is a sulfur atom, R ⁷ and R ⁸ or R ⁸ and R ⁹ may be bonded to form a ring containing S ⁺ , and the -CH ₂ - contained in the ring may be replaced with -O-, -S-, -CO-, -SO- or -SO ₂ -. R ⁷ and R ⁸ or R ⁸ and R ⁹ forming the ring may be a single bond formed between two benzene rings bonded to S ⁺ .

A ¹ , A ² and A ³ each independently represent a hydrocarbon group having 1 to 20 carbon atoms, the hydrocarbon group may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -CO-, -S- or -SO ₂ -.

m1 represents an integer of 1 to 5, and when m1 is 2 or more, the groups in multiple parentheses may be the same or different.
m2 represents an integer of 0 to 5, and when m2 is 2 or more, the groups in the parentheses may be the same or different.

m3 represents an integer of 0 to 5, and when m3 is 2 or more, the groups in the parentheses may be the same or different.
m4 represents an integer of 0 to 7, and when m4 is 2 or greater, multiple R ^4s may be the same or different.

m5 represents an integer of 0 to 7, and when m5 is 2 or greater, the multiple R ^5s may be the same or different.
m6 represents an integer of 0 to 7, and when m6 is 2 or greater, the multiple R ^6s may be the same or different.

m7 represents an integer of 0 to 4, and when m7 is 2 or greater, the multiple R ^7s may be the same or different.
m8 represents an integer of 0 to 5, and when m8 is 2 or greater, multiple R ^8s may be the same or different.

m9 represents an integer of 0 to 5, and when m9 is 2 or more, the multiple R ^9s may be the same or different.
However, 1≦m1+m7≦5, 0≦m2+m8≦5, and 0≦m3+m9≦5.

^AI- represents an organic anion.
[Invention 2]
A ¹ is ***-X ⁰¹ -L ⁰¹ - or ***-L ⁰¹ -X ⁰¹ -;
A ² is ***-X ⁰² -L ⁰² - or ***-L ⁰² -X ⁰² -;
A ³ is ***-X ⁰³ -L ⁰³ - or ***-L ⁰³ -X ⁰³ -;
X ⁰¹ , X ⁰² and X ⁰³ each independently represent —O—, —CO—, —S— or —SO ₂ —;
L ⁰¹ , L ⁰² and L ⁰³ each independently represent a single bond or a hydrocarbon group having 1 to 18 carbon atoms, the hydrocarbon group optionally having a substituent, and -CH ₂ - contained in the hydrocarbon group optionally being replaced by -O-, -CO-, -S- or -SO ₂ -;
The acid generator according to [Invention 1], wherein *** represents a bonding site between ^X and the benzene ring.

[Invention 3]
The acid generator according to [Invention 2], wherein X ⁰¹ , X ⁰² and X ⁰³ are each independently —O— or —S—.

[Invention 4]
The acid generator according to [Invention 2] or [Invention 3], wherein L ⁰¹ , L ⁰² and L ⁰³ each independently represent a single bond or an alkanediyl group having 1 to 6 carbon atoms (-CH ₂ - contained in the alkanediyl group may be replaced by -O- or -CO-).

[Invention 5]
The acid generator according to any one of [Invention 1] to [Invention 4], wherein the group having a cyclic carbonate structure for R ¹⁰ is a group represented by formula (Ix):

[In formula (Ix),
Ring W ^x represents a ring of a cyclic carbonate structure which may have a substituent, and --CH ₂ -- contained in the ring may be replaced by --O--, --CO--, --S-- or --NH--.

L ¹² represents a single bond or a hydrocarbon group having 1 to 36 carbon atoms which may have a substituent, and --CH ₂ -- contained in the hydrocarbon group may be replaced by --O--, --S--, --CO-- or --SO ₂ --.

* indicates a binding site.
[Invention 6]
The acid generator according to any one of [Invention 1] to [Invention 5], wherein Ar ¹ , Ar ² and Ar ³ are naphthalene.

[Invention 7]
The acid generator according to any one of [Invention 1] to [Invention 6], wherein AI ⁻ is a sulfonate anion, a sulfonylimide anion, or a sulfonylmethide anion.

[Invention 8]
The acid generator according to [Invention 7], wherein AI ⁻ is a sulfonate anion, which is an anion represented by formula (IA) or an anion represented by formula (IB).

[In formula (IA),
^Q1 and ^Q2 each independently represent a hydrogen atom, a fluorine atom, a perfluoroalkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms.

^L1 represents a saturated hydrocarbon group having 1 to 24 carbon atoms, in which _-CH2- may be replaced by -O- or -CO-, and in which a hydrogen atom may be replaced by a fluorine atom or a hydroxyl group.

^Y1 represents a methyl group which may have a substituent or a cyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, and -CH ₂ - contained in the cyclic hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-.]

[In formula (IB),
m21 represents an integer of 1 to 5, and when m21 is 2 or greater, the groups in the parentheses may be the same or different.

R ²¹ represents a hydrocarbon group having 3 to 48 carbon atoms, including a cyclic hydrocarbon group having 3 to 18 carbon atoms, the cyclic hydrocarbon group may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-.

R ²² represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and --CH ₂ -- contained in the alkyl group may be replaced by --O-- or --CO--.
m22 represents an integer of 0 to 4, and when m22 is 2 or greater, the multiple R ²² may be the same or different.
[Invention 9]
A resist composition comprising the acid generator according to any one of [Invention 1] to [Invention 8].

[Invention 10]
Further, the composition contains a resin including a structural unit having an acid labile group,
The resist composition according to [Invention 9], wherein the structural unit having an acid labile group includes at least one selected from the group consisting of a structural unit represented by formula (a1-0), a structural unit represented by formula (a1-1), and a structural unit represented by formula (a1-2):

[In formula (a1-0), formula (a1-1) and formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent --O-- or *-O--(CH ₂ ) _k1 --CO--O--, where k1 represents an integer of 1 to 7, and * represents a bonding site with --CO--.

R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a02 , R ^a03 and R ^a04 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof.

R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof.

m1' represents an integer of 0 to 14.
n1 represents an integer of 0 to 10.
n1' represents an integer of 0 to 3.
[Invention 11]
The resist composition according to [Invention 9] or [Invention 10], further comprising a resin that includes a structural unit having a fluorine atom.

[Invention 12]
The resist composition according to any one of [Invention 9] to [Invention 11], further comprising a salt that generates an acid that is weaker in acidity than the acid generated from the acid generator.

[Invention 13]
(1) A step of applying a resist composition according to any one of [Invention 9] to [Invention 12] onto a substrate;
(2) A step of drying the applied composition to form a composition layer;
(3) exposing the composition layer to light;
(4) a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.

[Invention 14]
A salt represented by the above formula (I).
[Invention 15]
A ¹ is ***-X ⁰¹ -L ⁰¹ - or ***-L ⁰¹ -X ⁰¹ -;
A ² is ***-X ⁰² -L ⁰² - or ***-L ⁰² -X ⁰² -;
A ³ is ***-X ⁰³ -L ⁰³ - or ***-L ⁰³ -X ⁰³ -;
X ⁰¹ , X ⁰² and X ⁰³ each independently represent —O—, —CO—, —S— or —SO ₂ —;
L ⁰¹ , L ⁰² and L ⁰³ each independently represent a single bond or a hydrocarbon group having 1 to 18 carbon atoms, the hydrocarbon group optionally having a substituent, and —CH ₂ — contained in the hydrocarbon group optionally being replaced by —O—, —CO—, —S— or —SO ₂ —;
The salt according to [Invention 14], wherein *** represents a bonding site between ^X and the benzene ring.

[Invention 16]
The salt according to [Invention 15], wherein X ⁰¹ , X ⁰² and X ⁰³ are each independently -O- or -S-.

[Invention 17]
The salt according to [Invention 15] or [Invention 16], wherein L ⁰¹ , L ⁰² and L ⁰³ each independently represent a single bond or an alkanediyl group having 1 to 6 carbon atoms (-CH ₂ - contained in the alkanediyl group may be replaced by -O- or -CO-).

[Invention 18]
The salt according to any one of [Invention 14] to [Invention 17], wherein the group having a cyclic carbonate structure for R ¹⁰ is a group represented by the above formula (Ix).

[Invention 19]
The salt according to any one of [Invention 14] to [Invention 18], wherein Ar ¹ , Ar ² and Ar ³ are naphthalene.

[Invention 20]
The salt according to any one of [Invention 14] to [Invention 19], wherein AI ⁻ is a sulfonate anion, a sulfonylimide anion, or a sulfonylmethide anion.

[Invention 21]
The salt according to [Invention 20], wherein AI ⁻ is a sulfonate anion, and the sulfonate anion is an anion represented by the above formula (IA) or an anion represented by the above formula (IB).

According to the present invention, it is possible to produce resist patterns with good line edge roughness (LER).

In this specification, "(meth)acrylic monomer" means "at least one of acrylic monomer and methacrylic monomer". The expressions "(meth)acrylate" and "(meth)acrylic acid" have the same meaning. In the groups described in this specification, those that can have both a linear structure and a branched structure may be either. When -CH ₂ - contained in a hydrocarbon group or the like is replaced with -O-, -S-, -CO- or -SO ₂ -, the same examples are applied to each group. "Combined group" means a group in which two or more of the exemplified groups are bonded, and the valence of these groups may be appropriately changed depending on the bond form. "Derived from" or "derived from" means that a polymerizable C═C bond contained in the molecule becomes a -C-C- group (single bond) by polymerization. When stereoisomers exist, all stereoisomers are included.

In this specification, the term "solids content of a resist composition" refers to the sum of the components excluding the solvent (E), which will be described later, from the total amount of the resist composition.
[Salt represented by formula (I)]
The present invention relates to a salt represented by formula (I) (hereinafter sometimes referred to as "salt (I)").

In the salt (I), the side having a positive charge is sometimes referred to as a "cation (I)" and the side having a negative charge is sometimes referred to as an "anion (I)".
[Cation (I)]
The cation (I) of the salt represented by formula (I) is a cation represented by formula (IC).

[In formula (IC), all symbols have the same meaning as in formula (I)]
In formula (I), examples of the alkanediyl group for L ¹⁰ contained in R ¹ , R ² , and R ³ include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group; and branched alkanediyl groups such as an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a pentane-2,4-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group.

L ¹⁰ is preferably an alkanediyl group having 1 to 3 carbon atoms, and more preferably a methylene group.
The cyclic carbonate structure of ^R10 contained in ^R1 , ^R2 , and ^R3 means a structure having -O-CO-O- as atoms constituting a ring. The cyclic carbonate structure may be monocyclic or polycyclic, and may have a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom in addition to the oxygen atom that forms the carbonate structure.

The number of carbon atoms in the cyclic carbonate structure may be 2 to 30, preferably 2 to 24, more preferably 2 to 18, even more preferably 2 to 16, and even more preferably 3 to 12. The ring of the cyclic carbonate structure is preferably a 3- to 18-membered ring, more preferably a 3- to 16-membered ring, even more preferably a 4- to 12-membered ring, even more preferably a 4- to 10-membered ring, even more preferably a 5- to 8-membered ring, and even more preferably a 5-membered ring. The ring may be a monocyclic structure or a bicyclic or tricyclic polycyclic structure. Two carbon atoms contained in the ring may be bonded by a double bond. When -CH ₂ - contained in the ring is replaced with -O- or the like, it is preferable that the -CH ₂ - that is not adjacent to -O-CO-O- is replaced with -O- or the like.

Examples of the cyclic carbonate structure include structures represented by formulas (x1) to (x17), and preferably structures represented by any of formulas (x1) to (x3), (x9) and (x16), more preferably structures represented by any of formulas (x1) to (x3), and even more preferably structures represented by formula (x1). The binding site may be at any position.

The cyclic carbonate structure may have a substituent, and examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, and a combination of two or more of these groups.

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a hexyl group. The number of carbon atoms in the alkyl group is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3.

The alicyclic hydrocarbon group may be monocyclic, polycyclic, or spirocyclic. Examples of the alicyclic hydrocarbon group include monocyclic cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, cyclononyl, cyclodecyl, and cyclododecyl, and polycyclic cycloalkyl groups such as norbornyl and adamantyl. The number of carbon atoms in the alicyclic hydrocarbon group is preferably 3 to 18, more preferably 3 to 16, and even more preferably 3 to 12.

Examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, and hexyloxy groups. The number of carbon atoms in the alkoxy group is preferably 1 to 4, and more preferably 1 to 3.

The group having a cyclic carbonate structure is preferably a group represented by formula (Ix).

[In formula (Ix),
Ring W ^x represents a ring of a cyclic carbonate structure which may have a substituent, and --CH ₂ -- contained in the ring may be replaced by --O--, --CO--, --S-- or --NH--.

L ¹² represents a single bond or a hydrocarbon group having 1 to 36 carbon atoms which may have a substituent, and --CH ₂ -- contained in the hydrocarbon group may be replaced by --O--, --S--, --CO-- or --SO ₂ --.

* indicates a binding site.
Examples of groups having a cyclic carbonate structure include the following structures: In the following groups, * indicates a bonding site.

Examples of the hydrocarbon group having 1 to 36 carbon atoms for L ¹² include aliphatic hydrocarbon groups (chain hydrocarbon groups and alicyclic hydrocarbon groups such as alkanediyl groups, alkenediyl groups, and alkynediyl groups), aromatic hydrocarbon groups, etc., and may be a hydrocarbon group consisting of a combination of two or more of these groups. -CH ₂ - contained in the hydrocarbon group for ^{L 12} may be replaced by -O-, -S-, -CO- or -SO ₂ -.

Alkanediyl groups include straight-chain alkanediyl groups such as methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, and dodecane-1,12-diyl groups. branched alkanediyl groups; branched alkanediyl groups such as ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group.

Examples of alkenediyl groups include ethenediyl, propenediyl, isopropenediyl, butenediyl, isobutenediyl, tert-butenediyl, pentenediyl, hexenediyl, heptenediyl, octenediyl, isooctenediyl, and nonenediyl groups.

Examples of alkynediyl groups include ethynediyl, propynediyl, isopropynediyl, butynediyl, isobutynediyl, tert-butynediyl, pentynediyl, hexynediyl, octynediyl, and nonynediyl groups.

The number of carbon atoms in the chain hydrocarbon group is preferably 1 to 24, more preferably 1 to 18, even more preferably 1 to 12, even more preferably 1 to 9, even more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of the group in which -CH ₂ - in an alkanediyl group is replaced with -O-, -S-, -CO- or -SO ₂ - include a hydroxy group (a group in which -CH ₂ - in a methyl group is replaced with -O-), a carboxy group (a group in which -CH ₂ -CH ₂ - in an ethyl group is replaced with -O-CO-), an oxy group (a group in which -CH ₂ - in a methylene group is replaced with -O-), a carbonyl group (a group in which -CH ₂ - in a methylene group is replaced with -CO-), a thio group (a group in which -CH ₂ - in a methylene group is replaced with -S-), a sulfonyl group (a group in which -CH ₂ - in a methylene group is replaced with -SO ₂ -), a thiol group (a group in which -CH 2 - in a methyl group is replaced with -SO ₂ -), and a methyl group. - is replaced with -S-), an alkanediyloxy group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced with -O-), an alkanediyloxycarbonyl group (a group in which -CH ₂ -CH ₂ - at any position contained in an alkanediyl group is replaced with -O-CO-), an alkanediylcarbonyl group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced with -CO-), an alkanediylcarbonyloxy group (a group in which -CH ₂ -CH ₂ - at any position contained in an alkanediyl group is replaced with -CO-O-), an alkanediylthio group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced with -S-), an alkanediylsulfonyl group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced with -SO ₂ - substituted groups).

Examples of alkanediyloxy groups include alkanediyloxy groups having 1 to 35 carbon atoms, such as methyleneoxy groups, ethyleneoxy groups, propanediyloxy groups, butanediyloxy groups, pentanediyloxy groups, hexanediyloxy groups, octanediyloxy groups, 2-ethylhexanediyloxy groups, nonanediyloxy groups, decanediyloxy groups, and undecanediyloxy groups. The number of carbon atoms in the alkanediyloxy group is preferably 1 to 17, more preferably 1 to 12, even more preferably 1 to 8, and even more preferably 1 to 5.

Examples of the alkanediyloxycarbonyl group include alkanediyloxycarbonyl groups having 2 to 35 carbon atoms, such as methyleneoxycarbonyl group, ethyleneoxycarbonyl group, propanediyloxycarbonyl group, butanediyloxycarbonyl group, pentanediyloxycarbonyl group, hexanediyloxycarbonyl group, octanediyloxycarbonyl group, 2-ethylhexanediyloxycarbonyl group, nonanediyloxycarbonyl group, decanediyloxycarbonyl group, and undecanediyloxycarbonyl group. The number of carbon atoms in the alkanediyloxycarbonyl group is preferably 2 to 17, more preferably 2 to 12, even more preferably 2 to 8, and even more preferably 2 to 5.

Examples of the alkanediylcarbonyl group include alkanediylcarbonyl groups having 2 to 36 carbon atoms, such as methylenecarbonyl, ethylenecarbonyl, propanediylcarbonyl, butanediylcarbonyl, pentanediylcarbonyl, hexanediylcarbonyl, octanediylcarbonyl, 2-ethylhexanediylcarbonyl, nonanediylcarbonyl, decanediylcarbonyl, and undecanediylcarbonyl. The number of carbon atoms in the alkanediylcarbonyl group is preferably 2 to 18, more preferably 2 to 12, even more preferably 2 to 8, and even more preferably 2 to 5.

Examples of the alkanediylcarbonyloxy group include alkanediylcarbonyloxy groups having 2 to 35 carbon atoms, such as methylenecarbonyloxy group, ethylenecarbonyloxy group, propanediylcarbonyloxy group, butanediylcarbonyloxy group, pentanediylcarbonyloxy group, hexanediylcarbonyloxy group, octanediylcarbonyloxy group, 2-ethylhexanediylcarbonyloxy group, nonanediylcarbonyloxy group, decanediylcarbonyloxy group, and undecanediylcarbonyloxy group. The number of carbon atoms in the alkanediylcarbonyloxy group is preferably 2 to 17, more preferably 2 to 12, even more preferably 2 to 8, and even more preferably 2 to 5.

Examples of the alkanediylthio group include alkanediylthio groups having 1 to 35 carbon atoms, such as methylenethio, ethylenethio, propanediylthio, butanediylthio, pentanediylthio, hexanediylthio, heptanediylthio, octanediylthio, nonanediylthio, decanediylthio, undecanediylthio, dodecanediylthio, and 2-methylpropanediylthio. The number of carbon atoms in the alkanediylthio group is preferably 1 to 17, more preferably 1 to 12, even more preferably 1 to 8, and even more preferably 1 to 5.

Examples of alkanediylsulfonyl groups include alkanediylsulfonyl groups having 1 to 35 carbon atoms, such as methylenesulfonyl groups, ethylenesulfonyl groups, and propylenesulfonyl groups. The number of carbon atoms in the alkanediylsulfonyl group is preferably 1 to 17, more preferably 1 to 12, even more preferably 1 to 8, and even more preferably 1 to 5.

The substitutions in the alkenediyl group and alkynediyl group may include a carbon-carbon double bond or a carbon-carbon triple bond at any position in the examples of substitutions in the alkanediyl group described above.

The alicyclic hydrocarbon group of the hydrocarbon group having 1 to 36 carbon atoms for L ¹² may be any of monocyclic, polycyclic and spirocyclic, and examples thereof include the groups shown below. The bonding site may be any position.

Specific examples of monocyclic alicyclic hydrocarbon groups include monocyclic cycloalkanediyl groups such as cyclobutane-1,3-diyl, cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, cyclohexene-3,6-diyl, and cyclooctane-1,5-diyl. Examples of polycyclic alicyclic hydrocarbon groups include polycyclic cycloalkanediyl groups such as norbornane-1,4-diyl, norbornane-2,5-diyl, 5-norbornene-2,3-diyl, adamantane-1,5-diyl, and adamantane-2,6-diyl. Examples of spirocyclic alicyclic hydrocarbon groups include cycloalkyl groups such as spirocyclohexane-1,2'-cyclopentane and spiroadamantane-2,3'-cyclopentane, and cycloalkyl groups bonded to a norbornyl group or an adamantyl group via a spiro bond.

The alicyclic hydrocarbon group preferably has 3 to 24 carbon atoms, more preferably 3 to 18 carbon atoms, even more preferably 3 to 16 carbon atoms, and even more preferably 3 to 12 carbon atoms.
Examples of groups in which --CH ₂ -- contained in an alicyclic hydrocarbon group is replaced by --O--, --S--, --CO-- or --SO ₂ -- include the groups shown below. --O-- or --CO-- in the groups shown below may be replaced by --S-- or --SO ₂ --. The bonding site may be at any position.

Examples of the aromatic hydrocarbon group of the hydrocarbon group having 1 to 36 carbon atoms for L ¹² include a phenylene group, a naphthylene group, an anthrylene group, a biphenylene group, a phenanthrylene group, etc. The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 24, more preferably 6 to 18, even more preferably 6 to 14, and even more preferably 6 to 10.

When a -CH ₂ - contained in a hydrocarbon group is replaced by -O-, -S-, -CO- or -SO ₂ -, the number of carbon atoms before the replacement is regarded as the total number of carbon atoms in the hydrocarbon group. In addition, the number may be 1 or 2 or more.

As the hydrocarbon group having 1 to 36 carbon atoms for L ¹² , examples of the hydrocarbon group obtained by combining two or more groups selected from chain hydrocarbon groups, aliphatic hydrocarbon groups, and aromatic hydrocarbon groups include a group obtained by combining an alkanediyl group with an alicyclic hydrocarbon group and/or an aromatic hydrocarbon group, and in the combination, two or more types of alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and chain hydrocarbon groups may each be combined. Examples include -alicyclic hydrocarbon group-alkanediyl group-, -alkanediyl group-alicyclic hydrocarbon group-, -alkanediyl group-alicyclic hydrocarbon group-, -alkanediyl group-alicyclic hydrocarbon group-alkanediyl group-, -alkanediyl group-aromatic hydrocarbon group-, and -aromatic hydrocarbon group-alkanediyl group-. Any of the groups may be bonded to an oxygen atom or a carbonyl group.

Examples of the substituent on the hydrocarbon group of L ¹² include a halogen atom, a cyano group, a hydroxy group, a carboxy group, an alkoxy group having 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyloxy group having 2 to 13 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyloxy group having 2 to 13 carbon atoms, and the like.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkoxy group having 1 to 12 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a 2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, an undecyloxy group, and a dodecyloxy group.

The alkoxycarbonyl group having 2 to 13 carbon atoms, the alkylcarbonyl group having 2 to 13 carbon atoms, and the alkylcarbonyloxy group having 2 to 13 carbon atoms represent groups in which a carbonyl group or a carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group.

Examples of alkoxycarbonyl groups having 2 to 13 carbon atoms include methoxycarbonyl groups, ethoxycarbonyl groups, and butoxycarbonyl groups. Examples of alkylcarbonyl groups having 2 to 13 carbon atoms include acetyl groups, propionyl groups, and butyryl groups. Examples of alkylcarbonyloxy groups having 2 to 13 carbon atoms include acetyloxy groups, propionyloxy groups, and butyryloxy groups.

The hydrocarbon group for L ¹² may have one or more substituents.
L ¹² is preferably a single bond, an alkanediyl group having 1 to 6 carbon atoms (-CH ₂ - contained in the alkanediyl group may be replaced with -O-, -S-, -SO ₂ - or -CO-), an alicyclic hydrocarbon group having 3 to 18 carbon atoms (-CH ₂ - contained in the alicyclic hydrocarbon group may be replaced with -O-, -S-, -SO ₂ - or -CO-) or a group combining an alkanediyl group having 1 to 6 carbon atoms with an alicyclic hydrocarbon group having 3 to 18 carbon atoms (-CH ₂ - contained in the alkanediyl group and the alicyclic hydrocarbon group may be replaced with -O-, -S-, -SO ₂ - or -CO-), more preferably a single bond or an alkanediyl group having 1 to 6 carbon atoms, even more preferably a single bond or an alkanediyl group having 1 to 3 carbon atoms, and even more preferably a single bond or a methylene group.

The bonding position of R ¹ to Ar ¹ is not particularly limited, but when Ar ¹ is naphthalene, anthracene or phenanthrene and A ¹ is bonded to the 1st or 2nd position of Ar ¹ , it is preferably bonded to the 3rd, 4th, 6th, or 7th position of Ar ¹ , and when Ar ¹ is anthracene or phenanthrene and A ¹ is bonded to the 9th position of Ar ¹ , it is preferably bonded to the 2nd, 3rd, or 4th position. The bonding positions of R ² and R ³ and A ² and A ³ to Ar ² and Ar ³ are also the same as the bonding positions of R ¹ and A ¹ to Ar ^1. Details of Ar ¹ and the like will be described later.

It is preferable that R ¹ , R ² and R ³ are each independently *-O-CO-R ¹⁰ , *-O-CO-O-R ¹⁰ or *-OL ¹⁰ -CO-O-R ¹⁰ , and it is more preferable that R 1 is *-O-CO-R ¹⁰ or *-OL ¹⁰ -CO-O-R ¹⁰ .

Examples of the halogen atom for R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
The haloalkyl group having 1 to 12 carbon atoms of R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ represents an alkyl group having 1 to 12 carbon atoms and a halogen atom, and examples thereof include a fluorinated alkyl group having 1 to 12 carbon atoms, a chlorinated alkyl group having 1 to 12 carbon atoms, a brominated alkyl group having 1 to 12 carbon atoms, and an iodinated alkyl group having 1 to 12 carbon atoms. Examples of the haloalkyl group include a perfluoroalkyl group having 1 to 12 carbon atoms (trifluoromethyl group, pentafluoroethyl group, heptafluoropropyl group, nonafluorobutyl group, etc.), a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoropropyl group, a 4,4,4-trifluorobutyl group, a 3,3,4,4,4-pentafluorobutyl group, a chloromethyl group, a bromomethyl group, and an iodomethyl group. The number of carbon atoms of the haloalkyl group is preferably 1 to 9, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of the hydrocarbon group having 1 to 36 carbon atoms for R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ include chain hydrocarbon groups such as alkyl groups and alkanediyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups and groups formed by combining these. The number of carbon atoms in the hydrocarbon group is preferably 1 to 30, more preferably 1 to 24, and even more preferably 1 to 18.

The alkyl group is a straight-chain or branched alkyl group, and examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl, and dodecyl groups.

The alkanediyl group is a linear or branched alkanediyl group, and examples thereof include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group; and branched alkanediyl groups such as an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a pentane-2,4-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group.

The number of carbon atoms in the chain hydrocarbon group is preferably 1 to 18, more preferably 1 to 12, even more preferably 1 to 9, still more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

The alicyclic hydrocarbon group may be monocyclic, polycyclic, or spirocyclic, and examples thereof include the groups shown below. The binding site may be any position.

Specific examples of monocyclic alicyclic hydrocarbon groups include monocyclic cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and cyclododecyl. Examples of polycyclic alicyclic hydrocarbon groups include polycyclic cycloalkyl groups such as decahydronaphthyl, adamantyl, and norbornyl. Examples of spirocyclic alicyclic hydrocarbon groups include cycloalkyl groups such as spirocyclohexane-1,2'-cyclopentane and spiroadamantane-2,3'-cyclopentane, and spiro rings having cycloalkyl groups bonded to norbornyl or adamantyl groups via spiro bonds. The number of carbon atoms in the alicyclic hydrocarbon group is preferably 3 to 18, more preferably 3 to 16, and even more preferably 3 to 12.

Examples of aromatic hydrocarbon groups include phenyl, naphthyl, biphenyl, anthryl, phenanthryl, and binaphthyl groups. The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 18, more preferably 6 to 14, and even more preferably 6 to 10.

Groups formed by combining two or more of the chain hydrocarbon group, alicyclic hydrocarbon group, and aromatic hydrocarbon group include a group formed by combining an aromatic hydrocarbon group with a chain hydrocarbon group (for example, aromatic hydrocarbon group-alkanediyl group-*, alkyl group-aromatic hydrocarbon group-*, alkyl group-aromatic hydrocarbon group-alkanediyl group-*, where the -CH ₂ - contained in the alkanediyl group and the alkyl group may be replaced with -O-, -CO-, -S-, -SO-, or -SO ₂ -), a group formed by combining an alicyclic hydrocarbon group with a chain hydrocarbon group (for example, alicyclic hydrocarbon group-alkanediyl group-*, alkyl group-alicyclic hydrocarbon group-*, alkyl group-alicyclic hydrocarbon group-alkanediyl group-*, where the -CH ₂ - contained in the alicyclic hydrocarbon group, the alkanediyl group, and the alkyl group may be replaced with -O-, -CO-, -S-, -SO-, or -SO _{2 -)} . -), and groups combining an aromatic hydrocarbon group with an alicyclic hydrocarbon group (for example, aromatic hydrocarbon group-alicyclic hydrocarbon group-*, alicyclic hydrocarbon group-aromatic hydrocarbon group-*, where -CH ₂ - contained in the alicyclic hydrocarbon group may be replaced by -O-, -CO-, -S-, -SO- or -SO ₂ -). * represents a bonding site.

The aromatic hydrocarbon group -alkanediyl group-* includes aralkyl groups such as benzyl group and phenethyl group.
Examples of the alkyl group-aromatic hydrocarbon group-* include a tolyl group, a xylyl group, and a cumenyl group.

Examples of the alicyclic hydrocarbon group -alkanediyl group-* include cycloalkylalkyl groups such as cyclohexylmethyl group, cyclohexylethyl group, 1-(adamantan-1-yl)methyl group, and 1-(adamantan-1-yl)-1-methylethyl group.

Examples of alkyl groups-alicyclic hydrocarbon groups-* include cycloalkyl groups having alkyl groups such as methylcyclohexyl groups, dimethylcyclohexyl groups, and 2-alkyladamantan-2-yl groups.

Examples of the aromatic hydrocarbon group-alicyclic hydrocarbon group-* include a phenylcyclohexyl group.
Examples of the alicyclic hydrocarbon group-aromatic hydrocarbon group-* include a cyclohexylphenyl group.

In the combination, two or more of the alicyclic hydrocarbon groups, aromatic hydrocarbon groups and chain hydrocarbon groups may be combined, and any of the groups may be bonded to Ar ¹ , Ar ² , Ar ³ or the benzene ring.

When a _-CH2- contained in the haloalkyl group or hydrocarbon group represented by ^R4 , ^R5 , ^R6 , ^R7 , ^R8 , and ^R9 is replaced by -O-, -CO-, -S-, -SO-, or _-SO2- , the number of carbon atoms before replacement is taken as the total number of carbon atoms in the haloalkyl group or hydrocarbon group. In addition, the number of _-CH2- replacing groups may be one or more.

Examples of haloalkyl groups and groups in which -CH ₂ - in a hydrocarbon group is replaced with -O-, -S-, -SO ₂ -, -SO- or -CO- include a hydroxy group (a group in which -CH ₂ - in a methyl group is replaced with -O-), a thiol group (a group in which -CH ₂ - in a methyl group is replaced with -S-), a carboxy group (a group in which -CH ₂ -CH ₂ - in an ethyl group is replaced with -O-CO-), a sulfenyl group (a group in which -CH ₂ - in a methyl group is replaced with -SO-), an alkoxy group (a group in which -CH ₂ - at any position in an alkyl group is replaced with -O-), an alkoxycarbonyl group (a group in which -CH ₂ -CH ₂ - at any position in an alkyl group is replaced with -O-CO-), an alkylcarbonyl group (a group in which -CH ₂ - - is replaced with -CO-), an alkylcarbonyloxy group (a group in which -CH ₂ -CH ₂ - at any position contained in an alkyl group is replaced with -CO-O-), an alkylthio group (a group in which -CH ₂ - at any position contained in an alkyl group is replaced with -S-), an alkylsulfonyl group (a group in which -CH ₂ - at any position contained in an alkyl group is replaced with -SO ₂ -), an oxy group (a group in which -CH ₂ - contained in a methylene group is replaced with -O-), a carbonyl group (a group in which -CH ₂ - contained in a methylene group is replaced with -CO-), a thio group (a group in which -CH ₂ - contained in a methylene group is replaced with -S-), a sulfonyl group (a group in which -CH ₂ - contained in a methylene group is replaced with -SO 2 -), an alkanediyloxy group (a group in which -CH _{2 -} at any position contained in an alkanediyl group is replaced with -SO ₂ -), - is replaced by -O-), an alkanediyloxycarbonyl group (a group in which -CH ₂ -CH ₂ - at any position contained in an alkanediyl group is replaced by -O-CO-), an alkanediylcarbonyl group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced by -CO-), an alkanediylcarbonyloxy group (a group in which -CH ₂ -CH ₂ - at any position contained in an alkanediyl group is replaced by -CO-O-), an alkanediylthio group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced by -S-), an alkanediylsulfonyl group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced by -SO ₂ -), a cycloalkoxy group, a cycloalkylalkoxy group, an alkoxycarbonyloxy group, an aromatic hydrocarbon group-carbonyloxy group, an aromatic hydrocarbon group-carbonyl group, an aromatic hydrocarbon group-oxy group, a haloalkoxy group (a group in which -CH ₂ - at any position contained in a haloalkyl group is replaced with -O-), a haloalkoxycarbonyl group (a group in which -CH ₂ -CH ₂ - at any position contained in a haloalkyl group is replaced with -O-CO-), a haloalkylcarbonyl group (a group in which -CH ₂ - at any position contained in a haloalkyl group is replaced with -CO-), a haloalkylcarbonyloxy group (a group in which -CH ₂ -CH ₂ - at any position contained in a haloalkyl group is replaced with -CO-O-), and a group combining two or more of these groups.

Examples of alkoxy groups include alkoxy groups having 1 to 35 carbon atoms, such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, and undecyloxy. The number of carbon atoms in the alkoxy group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

The alkoxycarbonyl group, alkylcarbonyl group, and alkylcarbonyloxy group refer to groups in which a carbonyl group or carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group.

Examples of the alkoxycarbonyl group include alkoxycarbonyl groups having 2 to 35 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, and butoxycarbonyl groups. Examples of the alkylcarbonyl group include alkylcarbonyl groups having 2 to 36 carbon atoms, such as acetyl, propionyl, and butyryl groups. Examples of the alkylcarbonyloxy group include alkylcarbonyloxy groups having 2 to 35 carbon atoms, such as acetyloxy, propionyloxy, and butyryloxy. The number of carbon atoms in the alkoxycarbonyl group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkylcarbonyloxy group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3.

Examples of alkylthio groups include alkylthio groups having 1 to 35 carbon atoms, such as methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, octylthio, 2-ethylhexylthio, nonylthio, decylthio, and undecylthio. The number of carbon atoms in the alkylthio group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of alkylsulfonyl groups include alkylsulfonyl groups having 1 to 35 carbon atoms, such as methylsulfonyl, ethylsulfonyl, propylsulfonyl, butylsulfonyl, pentylsulfonyl, hexylsulfonyl, octylsulfonyl, 2-ethylhexylsulfonyl, nonylsulfonyl, decylsulfonyl, and undecylsulfonyl groups. The number of carbon atoms in the alkylsulfonyl group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of alkanediyloxy groups include alkanediyloxy groups having 1 to 35 carbon atoms, such as methyleneoxy groups, ethyleneoxy groups, propanediyloxy groups, butanediyloxy groups, and pentanediyloxy groups. The number of carbon atoms in the alkanediyloxy group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of the alkanediyloxycarbonyl group include alkanediyloxycarbonyl groups having 2 to 35 carbon atoms, such as methyleneoxycarbonyl group, ethyleneoxycarbonyl group, propanediyloxycarbonyl group, butanediyloxycarbonyl group, etc. Examples of the alkanediylcarbonyl group include alkanediylcarbonyl groups having 2 to 36 carbon atoms, such as methylenecarbonyl group, ethylenecarbonyl group, propanediylcarbonyl group, butanediylcarbonyl group, pentanediylcarbonyl group, etc. Examples of the alkanediylcarbonyloxy group include alkanediylcarbonyloxy groups having 2 to 35 carbon atoms, such as methylenecarbonyloxy group, ethylenecarbonyloxy group, propanediylcarbonyloxy group, butanediylcarbonyloxy group, etc. The number of carbon atoms in the alkanediyloxycarbonyl group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkanediylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkanediylcarbonyloxy group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3.

Examples of alkanediylthio groups include alkanediylthio groups having 1 to 35 carbon atoms, such as methylenethio groups, ethylenethio groups, and propylenethio groups. The number of carbon atoms in the alkanediylthio group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of alkanediylsulfonyl groups include alkanediylsulfonyl groups having 1 to 35 carbon atoms, such as methylenesulfonyl groups, ethylenesulfonyl groups, and propylenesulfonyl groups. The number of carbon atoms in the alkanediylsulfonyl group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of cycloalkoxy groups include cycloalkoxy groups having 3 to 35 carbon atoms, such as cyclohexyloxy groups. Examples of cycloalkylalkoxy groups include cycloalkylalkoxy groups having 4 to 35 carbon atoms, such as cyclohexylmethoxy groups. Examples of alkoxycarbonyloxy groups include alkoxycarbonyloxy groups having 2 to 34 carbon atoms, such as butoxycarbonyloxy groups. Examples of aromatic hydrocarbon group-carbonyloxy groups include aromatic hydrocarbon group-carbonyloxy groups having 7 to 35 carbon atoms, such as benzoyloxy groups. Examples of aromatic hydrocarbon group-carbonyl groups include aromatic hydrocarbon group-carbonyl groups having 7 to 36 carbon atoms, such as benzoyl groups. Examples of aromatic hydrocarbon group-oxy groups include aromatic hydrocarbon group-oxy groups having 6 to 35 carbon atoms, such as phenyloxy groups.

Examples of haloalkoxy groups, haloalkoxycarbonyl groups, haloalkylcarbonyl groups, and haloalkylcarbonyloxy groups include haloalkoxy groups having 1 to 11 carbon atoms, haloalkoxycarbonyl groups having 2 to 11 carbon atoms, haloalkylcarbonyl groups having 2 to 12 carbon atoms, and haloalkylcarbonyloxy groups having 2 to 11 carbon atoms, such as groups in which one or more hydrogen atoms of the above-listed groups have been replaced with halogen atoms.

Furthermore, the group in which --CH ₂ -- contained in the alicyclic hydrocarbon group is replaced by --O--, --S--, --SO ₂ -- or --CO-- may form an ether ring structure, a ketone ring structure, a lactone ring structure, a sultone ring structure or an acetal ring structure, and examples thereof include the groups shown below. Further examples thereof include, among the groups shown below, groups in which --O-- is replaced by --S-- and --CO-- is replaced by --SO ₂ --. The bonding site may be at any position.

Examples of the substituent that the hydrocarbon group of R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ may have include a halogen atom and a cyano group.
Examples of the halogen atom include the same groups as those mentioned above.

The hydrocarbon group may have one substituent or multiple substituents.
The hydrocarbon groups of A ¹ , A ² and A ³ include linear or branched chain hydrocarbon groups (e.g., alkanediyl groups, etc.), monocyclic or polycyclic alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and may be combinations of two or more of these groups. The number of carbon atoms in the hydrocarbon group is preferably 1 to 19, more preferably 1 to 18, even more preferably 1 to 16, still more preferably 1 to 14, and even more preferably 1 to 12.

Examples of the chain hydrocarbon group include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, a dodecane-1,12-diyl group, a tridecane-1,13-diyl group, a tetradecane-1,14-diyl group, a pentadecane-1,15-diyl group, a hexadecane-1,16-diyl group, and a heptadecane-1,17-diyl group; Examples of branched alkanediyl groups include ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group.

The number of carbon atoms in the chain hydrocarbon group is preferably 1 to 18, more preferably 1 to 12, even more preferably 1 to 9, even more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Alicyclic hydrocarbon groups may be monocyclic, polycyclic, or spirocyclic, and include the groups shown below. The binding site may be any position.

Specific examples of monocyclic alicyclic hydrocarbon groups include monocyclic cycloalkanediyl groups such as cyclobutane-1,3-diyl, cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, and cyclooctane-1,5-diyl. Examples of polycyclic alicyclic hydrocarbon groups include polycyclic cycloalkanediyl groups such as norbornane-1,4-diyl, norbornane-2,5-diyl, adamantane-1,5-diyl, and adamantane-2,6-diyl. Examples of spirocyclic alicyclic hydrocarbon groups include cycloalkyl groups such as spirocyclohexane-1,2'-cyclopentane and spiroadamantane-2,3'-cyclopentane, and cycloalkyl groups bonded to a norbornyl group or an adamantyl group via a spiro bond.

The alicyclic hydrocarbon group preferably has 3 to 18 carbon atoms, more preferably 3 to 16 carbon atoms, even more preferably 3 to 12 carbon atoms, and even more preferably 3 to 10 carbon atoms.
Examples of the aromatic hydrocarbon group include arylene groups such as a phenylene group, a naphthylene group, an anthrylene group, a biphenylene group, a phenanthrylene group, etc. The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 18, more preferably 6 to 14, and further preferably 6 to 10.

Examples of groups that combine two or more types of groups include a group that combines an alicyclic hydrocarbon group with an alkanediyl group, a group that combines an aromatic hydrocarbon group with an alkanediyl group, and a group that combines an alicyclic hydrocarbon group with an aromatic hydrocarbon group. In the combination, two or more types of each of the chain hydrocarbon group, the alicyclic hydrocarbon group, and the aromatic hydrocarbon group may be combined. In addition, any of the groups may be bonded to a benzene ring.

Examples of groups that combine an alicyclic hydrocarbon group and an alkanediyl group include -divalent alicyclic hydrocarbon group-alkanediyl group-, -alkanediyl group-divalent alicyclic hydrocarbon group-alkanediyl group-, -alkanediyl group-divalent alicyclic hydrocarbon group-, etc.

Examples of groups that combine an aromatic hydrocarbon group and an alkanediyl group include -divalent aromatic hydrocarbon group-alkanediyl group-, -alkanediyl group-divalent aromatic hydrocarbon group-alkanediyl group-, -alkanediyl group-divalent aromatic hydrocarbon group-, etc.

Examples of groups that combine an alicyclic hydrocarbon group and an aromatic hydrocarbon group include -aromatic hydrocarbon group-alicyclic hydrocarbon group-, -alicyclic hydrocarbon group-aromatic hydrocarbon group-, -alicyclic hydrocarbon group-aromatic hydrocarbon group-, and -alicyclic hydrocarbon group-aromatic hydrocarbon group-alicyclic hydrocarbon group-.

In A ¹ , A ² and A ³ , when -CH ₂ - in the hydrocarbon group is replaced by -O-, -CO-, -S- or -SO ₂ -, the number of carbon atoms before the replacement is regarded as the total number of carbon atoms in the hydrocarbon group. The number of -CH ₂ - replacing groups may be one or may be two or more, but is preferably one to three.

Examples of groups in which -CH ₂ - in a hydrocarbon group is replaced by -O-, -CO-, -S- or -SO ₂ - include a hydroxy group (a group in which -CH ₂ - in a methyl group is replaced by -O-), a carboxy group (a group in which -CH ₂ -CH ₂ - in an ethyl group is replaced by -O-CO-), a thiol group (a group in which -CH ₂ - in a methyl group is replaced by -S-), an alkoxy group (a group in which -CH ₂ - at any position in an alkyl group is replaced by -O-), an alkoxycarbonyl group (a group in which -CH ₂ -CH ₂ - at any position in an alkyl group is replaced by -O-CO-), an alkylcarbonyl group (a group in which -CH ₂ - at any position in an alkyl group is replaced by -CO-), and an alkylcarbonyloxy group (a group in which -CH ₂ -CH _{2 -} at any position in an alkyl group is replaced by -CO-). - is replaced with -CO-O-), an alkylthio group (a group in which -CH ₂ - at any position contained in an alkyl group is replaced with -S-), an alkylsulfonyl group (a group in which -CH ₂ - at any position contained in an alkyl group is replaced with -SO ₂ -), an oxy group (a group in which -CH ₂ - contained in a methylene group is replaced with -O-), a carbonyl group (a group in which -CH ₂ - contained in a methylene group is replaced with -CO-), a thio group (a group in which -CH ₂ - contained in a methylene group is replaced with -S-), a sulfonyl group (a group in which -CH ₂ - contained in a methylene group is replaced with -SO ₂ -), an alkanediyloxy group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced with -O-), an alkanediyloxycarbonyl group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced with -O-), Examples of the alkyl group include an alkanediyl group in which -CH ₂ - is replaced with -O-CO-), an alkanediylcarbonyl group (an alkanediyl group in which -CH ₂ - at any position is replaced with -CO-), an alkanediylcarbonyloxy group (an alkanediyl group in which -CH ₂ -CH ₂ - at any position is replaced with -CO-O-), an alkanediylsulfonyl group (an alkanediyl group in which -CH ₂ - at any position is replaced with -SO ₂ -), an alkanediylthio group (an alkanediyl group in which -CH ₂ - at any position is replaced with -S-), a cycloalkoxy group, a cycloalkylalkoxy group, an alkoxycarbonyloxy group, an aromatic hydrocarbon group-carbonyloxy group, an aromatic hydrocarbon group-carbonyl group, an aromatic hydrocarbon group-oxy group, and a group formed by combining two or more of these groups.

Examples of alkoxy groups include alkoxy groups having 1 to 19 carbon atoms, such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, and undecyloxy. The number of carbon atoms in the alkoxy group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

The alkoxycarbonyl group, alkylcarbonyl group, and alkylcarbonyloxy group refer to groups in which a carbonyl group or carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group.

Examples of the alkoxycarbonyl group include alkoxycarbonyl groups having 2 to 19 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, and butoxycarbonyl groups. Examples of the alkylcarbonyl group include alkylcarbonyl groups having 2 to 20 carbon atoms, such as acetyl, propionyl, and butyryl groups. Examples of the alkylcarbonyloxy group include alkylcarbonyloxy groups having 2 to 19 carbon atoms, such as acetyloxy, propionyloxy, and butyryloxy groups. The number of carbon atoms in the alkoxycarbonyl group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkylcarbonyloxy group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3.

Examples of alkylthio groups include alkylthio groups having 1 to 19 carbon atoms, such as methylthio, ethylthio, propylthio, and butylthio groups. The number of carbon atoms in the alkylthio group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of alkylsulfonyl groups include alkylsulfonyl groups having 1 to 19 carbon atoms, such as methylsulfonyl groups, ethylsulfonyl groups, and propylsulfonyl groups. The number of carbon atoms in the alkylsulfonyl group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of alkanediyloxy groups include alkanediyloxy groups having 1 to 19 carbon atoms, such as methyleneoxy groups, ethyleneoxy groups, propanediyloxy groups, butanediyloxy groups, and pentanediyloxy groups. The number of carbon atoms in the alkanediyloxy group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of the alkanediyloxycarbonyl group include alkanediyloxycarbonyl groups having 2 to 19 carbon atoms, such as methyleneoxycarbonyl group, ethyleneoxycarbonyl group, propanediyloxycarbonyl group, butanediyloxycarbonyl group, etc. Examples of the alkanediylcarbonyl group include alkanediylcarbonyl groups having 2 to 20 carbon atoms, such as methylenecarbonyl group, ethylenecarbonyl group, propanediylcarbonyl group, butanediylcarbonyl group, etc. Examples of the alkanediylcarbonyloxy group include alkanediylcarbonyloxy groups having 2 to 19 carbon atoms, such as methylenecarbonyloxy group, ethylenecarbonyloxy group, propanediylcarbonyloxy group, butanediylcarbonyloxy group, etc. The number of carbon atoms in the alkanediyloxycarbonyl group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkanediylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkanediylcarbonyloxy group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3.

Examples of alkanediylsulfonyl groups include alkanediylsulfonyl groups having 1 to 19 carbon atoms, such as methylenesulfonyl groups, ethylenesulfonyl groups, and propylenesulfonyl groups. The number of carbon atoms in the alkanediylsulfonyl group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of alkanediylthio groups include alkanediylthio groups having 1 to 19 carbon atoms, such as methylenethio groups, ethylenethio groups, and propylenethio groups. The number of carbon atoms in the alkanediylthio group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of cycloalkoxy groups include cycloalkoxy groups having 3 to 19 carbon atoms, such as cyclohexyloxy groups. Examples of cycloalkylalkoxy groups include cycloalkylalkoxy groups having 4 to 19 carbon atoms, such as cyclohexylmethoxy groups. Examples of alkoxycarbonyloxy groups include alkoxycarbonyloxy groups having 2 to 18 carbon atoms, such as butoxycarbonyloxy groups. Examples of aromatic hydrocarbon group-carbonyloxy groups include aromatic hydrocarbon group-carbonyloxy groups having 7 to 19 carbon atoms, such as benzoyloxy groups. Examples of aromatic hydrocarbon group-carbonyl groups include aromatic hydrocarbon group-carbonyl groups having 7 to 20 carbon atoms, such as benzoyl groups. Examples of aromatic hydrocarbon group-oxy groups include aromatic hydrocarbon group-oxy groups having 6 to 19 carbon atoms, such as phenyloxy groups.

Furthermore, the group in which --CH ₂ -- contained in the alicyclic hydrocarbon group is replaced by --O--, --CO--, --S-- or --SO ₂ -- may form an ether ring structure, a ketone ring structure, a lactone ring structure, a sultone ring structure or an acetal ring structure, and examples thereof include the groups shown below. Further examples thereof include, among the groups shown below, groups in which --O-- is replaced by --S-- and --CO-- is replaced by --SO ₂ --. The bonding site may be at any position.

Examples of the substituent which the hydrocarbon groups of A ¹ , A ² and A ³ may have include the same groups as those exemplified as the substituents which the hydrocarbon groups of R ⁴ to R ⁹ may have.
It is preferable that A ¹ , A ² and A ³ are each independently a hydrocarbon group having 1 to 20 carbon atoms (the hydrocarbon group may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -CO-, -S- or -SO ₂ -, with the proviso that at least one of the -CH ₂ - contained in the hydrocarbon group is replaced by -O-, -CO-, -S- or -SO ₂ -). Specifically, A ¹ is ***-L ⁰¹¹ -X ⁰¹ -L ⁰¹² -, A ² is ***-L ⁰²¹ -X ⁰² -L ⁰²² -, and A ³ is ***-L ⁰³¹ -X ⁰³ -L ⁰³² - (X ⁰¹ , X ⁰² and X ⁰³ each independently represent -O-, -CO-, -S- or -SO ₂ -. L ⁰¹¹ , L ⁰¹² , L ⁰²¹ , L ⁰²² , L ⁰³¹ and L ⁰³² each independently represent a single bond or a hydrocarbon group having 1 to 19 carbon atoms, which may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -CO-, -S- or -SO ₂ -. However, L The total number of carbon atoms in L ⁰¹¹ and L ⁰¹² is 0 to 19, the total number of carbon atoms in L ⁰²¹ and L ⁰²² is 0 to 19, and the total number of carbon atoms in L ⁰³¹ and L ⁰³² is 0 to 19. *** represents a bonding site with the benzene ring to which X ⁺ is bonded.) is more preferable, A ¹ is ***-X ⁰¹ -L ⁰¹ - or ***-L ⁰¹ -X ⁰¹ -, A ² is ***-X ⁰² -L ⁰² - or ***-L ⁰² -X ⁰² -, and A ³ is ***-X ⁰³ -L ⁰³ - or ***-L ⁰³ -X ⁰³ - (X ⁰¹ , X ⁰² and X ⁰³ are each independently -O-, -CO-, -S- or -SO ₂ -. L ⁰¹ , L ⁰² and L ⁰³ each independently represent a single bond or a hydrocarbon group having 1 to 19 carbon atoms, which may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -CO-, -S- or -SO ₂ -. *** represents the bonding site with the benzene ring to which X ⁺ is bonded.) is more preferable. It is preferable that A ¹ , A ² and A ³ do not have a substituent other than replacement by -O-, -CO-, -S- or -SO ₂ -.

The hydrocarbon group having 1 to 19 carbon atoms for L ⁰¹¹ , L ⁰¹² , L ⁰²¹ , L ⁰²² , L ⁰³¹ , L ⁰³² , L ⁰¹ , L ⁰² and L ⁰³ (the hydrocarbon group may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -CO-, -S- or -SO ₂ -) includes groups having a carbon number in the range of 1 to 19, similar to the groups exemplified for A ¹ , A ² and A ³ .

X ⁰¹ , X ⁰² and X ⁰³ each independently preferably represent —O— or —S—, more preferably —O—.
L ⁰¹¹ , L ⁰¹² , L ⁰²¹ , L ⁰²² , L ⁰³¹ , L ⁰³² , L ⁰¹ , L ⁰² and L ⁰³ are each independently preferably a single bond or a hydrocarbon group having 1 to 18 carbon atoms (wherein -CH ₂ - may be replaced by -O-, -CO-, -S- or -SO ₂ -), more preferably a single bond or a hydrocarbon group having 1 to 12 carbon atoms (wherein -CH ₂ - may be replaced by -O-, -CO-, -S- or -SO ₂ -), and more preferably a single bond or a chain hydrocarbon group having 1 to 9 carbon atoms (wherein -CH ₂ - contained in the chain hydrocarbon group may be replaced by -O-, -CO-, -S- or -SO _{2 -} ). -), still more preferably a single bond or an alkanediyl group having 1 to 6 carbon atoms (-CH ₂ - contained in the alkanediyl group may be replaced by -O- or -CO-), still more preferably a single bond or an alkanediyl group having 1 to 4 carbon atoms (-CH ₂ - contained in the alkanediyl group may be replaced by -O- or -CO-), and still more preferably a single bond or an alkanediyl group having 1 to 3 carbon atoms (-CH ₂ - contained in the alkanediyl group may be replaced by -O- or -CO-). Among these, a single bond, a methylene group, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-2,2-diyl group, a carbonyl group, a carbonyloxy group, a carbonyloxymethylene group, an ethyleneoxy group, an ethyleneoxymethylene group, a methylenecarbonyloxy group, a methylenecarbonyloxymethylene group, or an ethyleneoxycarbonyl group is preferred, and a single bond, a methylene group, or a carbonyl group is more preferred.

The bonding positions of A ¹ , A ² and A ³ in the benzene ring ^to which X ⁺ is bonded may be independently any of o-position, m-position and p-position with respect to the bonding position of X ⁺ . In particular, it is preferable that they are bonded to the p-position or m-position with respect to the bonding position of X ⁺ . More specifically, when m1, m2 and m3 are 1, A ¹ , A ² and A ³ are each independently bonded to the p-position or m-position with respect to the bonding position of X +, and more preferably bonded to the p-position. When m1, m2 and m3 are 2, A ¹ , A ² and A ³ are each independently bonded to the o-position or m-position with respect to the bonding position of X ⁺ , and it is more preferable that they are bonded to the m-position. When m1, m2, and m3 are 3, A ¹ , A ² , and A ³ are each independently preferably two bonded to the o-position or m-position and one bonded to the p-position or m-position relative to the bonding position of ^{X +} , and more preferably two bonded to the m-position and one bonded to the p-position. When m1, m2, and m3 are 4, A ¹ , A ² , and A ³ are each independently preferably two bonded to the o-position or m-position and two bonded to the p-position or m-position relative to the bonding position of X ⁺ , and more preferably two bonded to the o-position and two bonded to the m-position.

When Ar ¹ is naphthalene, anthracene or phenanthrene, the bonding position of A ¹ to Ar ¹ is preferably position ¹ , 2 or 9, more preferably position 1 or 2. The bonding positions of A ² to Ar ² and A ³ to Ar ³ are the same as the bonding position of A ¹ to Ar ¹ .

m1 is preferably 1, 2, 3 or 4, more preferably 1, 2 or 3, even more preferably 1 or 2, and even more preferably 1.
m2 is preferably 0, 1, 2, 3 or 4, more preferably 0, 1, 2 or 3, even more preferably 0, 1 or 2, even more preferably 0 or 1, and even more preferably 0.

m3 is preferably 0, 1, 2, 3 or 4, more preferably 0, 1, 2 or 3, even more preferably 0, 1 or 2, even more preferably 0 or 1, and even more preferably 0.

m4 is preferably 0, 1, 2, 3, 4 or 5, more preferably 0, 1, 2, 3 or 5, and even more preferably 0, 1, 2 or 3.
m5 is preferably 0, 1, 2, 3, 4 or 5, more preferably 0, 1, 2, 3 or 5, and even more preferably 0, 1, 2 or 3.

m6 is preferably 0, 1, 2, 3, 4 or 5, more preferably 0, 1, 2, 3 or 5, and further preferably 0, 1, 2 or 3.
m7 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and further preferably 0 or 1.

m8 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and further preferably 0 or 1.
m9 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and further preferably 0 or 1.

R ⁴ , R ⁵ and R ⁶ are each independently preferably a halogen atom, a fluorinated alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms (wherein the -CH ₂ - contained in the alkyl group may be replaced with -O- or -CO-), more preferably a halogen atom, a fluorinated alkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms (wherein the -CH ₂ - contained in the alkyl group may be replaced with -O- or -CO-), still more preferably a fluorine atom, an iodine atom, a bromine atom, a perfluoroalkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms (wherein the -CH ₂ - contained in the alkyl group may be replaced with -O- or -CO-), and still more preferably a fluorine atom, an iodine atom, a bromine atom, a trifluoromethyl group, a hydroxy group, a methoxy group, a methyl group or a t-butyl group.

R ⁷ , R ⁸ and R ⁹ are each independently preferably a halogen atom, a fluorinated alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms (wherein the -CH ₂ - contained in the alkyl group may be replaced with -O- or -CO-), more preferably a halogen atom, a fluorinated alkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms (wherein the -CH ₂ - contained in the alkyl group may be replaced with -O- or -CO-), still more preferably a fluorine atom, an iodine atom, a perfluoroalkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms (wherein the -CH ₂ - contained in the alkyl group may be replaced with -O- or -CO-), and still more preferably a fluorine atom, an iodine atom, a trifluoromethyl group, a hydroxy group, a methoxy group, a methyl group or a t-butyl group.

The bonding position of R ⁴ to Ar ¹ is not particularly limited, but when Ar ¹ is naphthalene, anthracene or phenanthrene and A ¹ is bonded to the 1st or 2nd position of Ar ¹ , it is preferable that at least one is bonded to the 1st, 3rd, 4th, 5th, or 7th position of Ar ¹ , and when Ar ¹ is anthracene or phenanthrene and A ¹ is bonded to the 9th position of Ar ¹ , it is preferable that at least one is bonded to the 2nd, 3rd, or 4th position. The bonding positions of R ⁵ and R ⁶ and A ² and A ³ to Ar ² and Ar ³ are the same as the bonding positions of R ⁴ and A ¹ to Ar ^1. In addition, it is preferable that at least one of the bonding positions of R ⁴ , R ⁵ , and R ⁶ to Ar ¹ , Ar ² , and Ar ³ is adjacent to R ¹ , R ² , and R ³ , respectively.

The bonding positions of R ⁷ , R ⁸ and R ⁹ to the benzene ring may be, independently, any of o-position, m-position and p-position with respect to the bonding position of X ⁺ . In particular, when m7, m8 and m9 are 1, R ⁷ , R ⁸ and R ⁹ are, independently, preferably, bonded to the p-position or m-position with respect to the bonding position of X ⁺ , and more preferably, bonded to the p-position. When m7, m8 and m9 are 2, R ⁷ , R ⁸ and R ⁹ are, independently, preferably, one is bonded to the o-position or m-position with respect to the bonding position of X ⁺ , and one is bonded to the p-position or m-position, and more preferably, one is bonded to the m-position and one is bonded to the p-position or m-position. When m7, m8, and m9 are 3, it is preferable that R ⁷ , R ⁸ , and R ⁹ are each independently bonded to the o ^- position or m-position, and one is bonded to the p-position or m-position, and it is more preferable that two are bonded to the m-position and one is bonded to the p-position, with respect to the bonding position of X ⁺ . When m7, m8, and m9 are 4, it is preferable that R ⁷ , R ⁸ , and R ⁹ are each independently bonded to the o-position or m-position, and two are bonded to the p-position or m-position, and it is more preferable that two are bonded to the m-position, one is bonded to the o-position, and one is bonded to the p-position, with respect to the bonding position of X +.

In another embodiment, at least one of one or more of R ⁴ , R ⁵ and R ⁶ may contain a group having a cyclic carbonate structure, and R ⁴ , R ⁵ and R ⁶ may each independently be the same group as R ¹ , R ² and R ^3. When R ¹ is -O-R ¹⁰ , it is preferable that one or two R ⁴ are the same as R ¹ -O-R ¹⁰ , when R ¹ is -O-CO-R ¹⁰ , it is preferable that one or two R ⁴ are the same as R ¹ -O-CO-R ¹⁰ , when R ¹ is -O-CO-O-R ¹⁰ , it is preferable that one or two R ⁴ are the same as R ¹ -O-CO-O-R ¹⁰ , when R ¹ is -O-L ¹⁰ -CO-O-R ¹⁰ , it is preferable that one or two R ⁴ are the same as R ¹ -O-L ¹⁰ -CO-O-R ¹⁰ . The combinations of ^R2 and ^R5 and ^R3 and ^R6 are similar to the combinations of ^R1 and ^R4 .

Ar ¹ , Ar ² and Ar ³ are each preferably independently naphthalene, anthracene or phenanthrene, more preferably naphthalene or anthracene, and further preferably naphthalene.

Furthermore, when m10=1, that is, when X is a sulfur atom, in the cation (I), R ⁷ and R ⁸ or R ⁸ and R ⁹ may be bonded to form a ring containing S ⁺ . When R ⁸ and R ⁹ are bonded to form a ring containing S ⁺ , the cation (I) is preferably a cation represented by formula (IC').

[In formula (IC'),
The symbols ^R1 , ^R2 , ^R3 , ^R4 , ^R5 , ^R6 , ^R7 , ^R8 , ^R9 , m1, m2, m3, m4, m5, m6, m7, m8, m9, ^A1 , ^A2 , ^A3 , ^Ar1 , ^Ar2 , and ^Ar3 have the same meanings as defined above.

^X7 represents a single bond, _-CH2- , -O-, -CO-, -SO-, _-SO2- or -S-.]
X ⁷ is preferably a single bond, —CH ₂ — or —O—.

Cation (I) represented by formula (I-C) includes cations represented by formula (I-C-1), formula (I-C-2) or formula (I-C'-1) (hereinafter, these may be referred to as "cation (I-C-1)", "cation (I-C-2)" and "cation (I-C'-1)", respectively).

[In formula (IC-1), formula (IC-2) and formula (IC'-1),
The symbols Ar ¹ , Ar ² , Ar ³ , R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , m1, m2, m3, m4, m5, m6, m7, m8, m9, X ⁷ , L ⁰¹ , L ⁰² , L ⁰³ , X ⁰¹ , X ⁰² and X ⁰³ have the same meanings as above.]
In formula (IC-1), formula (IC-2) and formula (IC'-1), the bonding positions of ^X01 , ^X02 and ^X03 in the benzene ring to which X ⁺ is bonded are the same as the bonding positions of ^A1 , ^A2 and ^A3 in the benzene ring to which X ⁺ is bonded in formula (I), respectively.

Other preferred embodiments of the cation represented by formula (IC) include cations represented by formula (IC-3), formula (IC-4) or formula (IC'-3) in which Ar ¹ , Ar ² and Ar ³ are naphthalene or anthracene, respectively (hereinafter, these may be referred to as "cation (IC-3)", "cation (IC-4)" and "cation (IC'-3)", respectively).

[In formula (IC-3), formula (IC-4) and formula (IC'-3),
The symbols ^R1 , ^R2 , ^R3 , ^R7 , R8, ^R9 , ^m1 , m2, m3, m7, m8, m9, ^X7 , ^A1 , ^A2 and ^A3 have the same meanings as in formula (I) etc.

R ^4A , R ^5A and R ^6A each independently represent a halogen atom, a fluorinated alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms, and the -CH ₂ - contained in the fluorinated alkyl group and the alkyl group may be replaced with -O- or -CO-.

m1A, m2A and m3A each independently represent 0 or 1.
m4A, m5A and m6A each independently represent 0, 1, 2, 3, 4 or 5.
R ¹ to R ³ , R ⁷ to R ⁹ , ml to m3, m7 to m9, X ⁷ , and A ¹ to A ³ each have the same meaning as above, and examples thereof include the same as those mentioned above.

Examples ^of the halogen ^atom , fluorinated alkyl group having 1 to 6 carbon atoms, and alkyl group having 1 to 6 carbon atoms (the —CH ₂ — contained in the fluorinated alkyl group and the alkyl group may be replaced by —O— or ^—CO— ) of R 4A, R 5A, and R 6A are the same as those given above for R ⁴ to R ⁵ .
m4A, m5A and m6A are each preferably 0, 1, 2, 3 or 5, and more preferably 0, 1, 2 or 3.

Cations of salt (I) include those represented by the following formulas (I-c-1) to (I-c-252).

[Anion (I)]
The anion (I) of the salt represented by formula (I) is an organic anion represented by ^AI- .
Examples of the organic anion represented by ^AI- include a sulfonate anion, a sulfonylimide anion, a sulfonylmethide anion, etc. The organic anion represented by ^AI- is preferably a sulfonate anion, and more preferably an anion represented by formula (IA) or an anion represented by formula (IB).

[In formula (IA),
^Q1 and ^Q2 each independently represent a hydrogen atom, a fluorine atom, an alkyl group having 1 to 6 carbon atoms, or a perfluoroalkyl group having 1 to 6 carbon atoms.

^L1 represents a saturated hydrocarbon group having 1 to 24 carbon atoms, in which _-CH2- may be replaced by -O- or -CO-, and in which a hydrogen atom may be replaced by a fluorine atom or a hydroxyl group.

^Y1 represents a methyl group which may have a substituent or a cyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, and -CH ₂ - contained in the cyclic hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-.]
In formula (IA), when -CH ₂ - in the saturated hydrocarbon group is replaced with -O- or -CO-, the number of carbon atoms before the replacement is defined as the number of carbon atoms in the saturated hydrocarbon group. Also, when -CH ₂ - in the cyclic hydrocarbon group is replaced with -O-, -S-, -SO ₂ - or -CO-, the number of carbon atoms before the replacement is defined as the number of carbon atoms in the cyclic hydrocarbon group.

Examples of the perfluoroalkyl group having 1 to 6 carbon atoms for ^Q1 and ^Q2 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluorohexyl group.

Examples of the alkyl group having 1 to 6 carbon atoms for Q ¹ and Q ² include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group.

At least one ^{of Q1} and ^Q2 preferably contains a fluorine atom or a perfluoroalkyl group ^, more preferably each independently is a fluorine atom or a perfluoroalkyl group, further preferably is a fluorine atom or a trifluoromethyl group, and further more preferably is both a fluorine atom.

Examples of the saturated hydrocarbon group for L ¹ include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and a group consisting of a combination of two or more of these groups may also be used.

Specifically, linear alkanediyl groups such as methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, and heptadecane-1,17-diyl groups; ethane-1,1-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-1,4-diyl, propane-1,5-diyl, propane-1,6-diyl, and propane-1,7-diyl groups; Examples of branched alkanediyl groups include propane-2,2-diyl, pentane-2,4-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl, pentane-1,4-diyl, and 2-methylbutane-1,4-diyl groups; monocyclic divalent alicyclic saturated hydrocarbon groups such as cycloalkanediyl groups, such as cyclobutane-1,3-diyl, cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, and cyclooctane-1,5-diyl groups; and polycyclic divalent alicyclic saturated hydrocarbon groups, such as norbornane-1,4-diyl, norbornane-2,5-diyl, adamantane-1,5-diyl, and adamantane-2,6-diyl groups. The terminal of the branched alkanediyl group may be a methyl group.

Examples of the saturated hydrocarbon group represented by ^L1 in which -CH ₂ - is replaced by -O- or -CO- include groups represented by any of formulas (b1-1) to (b1-3). In the groups represented by formulas (b1-1) to (b1-3) and specific examples thereof represented by formulas (b1-4) to (b1-11), * and ** represent bonding sites, and * represents a bonding site with ^Y1 .

[In formula (b1-1),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.

L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and -CH ₂ - contained in the saturated hydrocarbon group may be substituted with -O- or -CO-.

However, the total number of carbon atoms in L ^b2 and L ^b3 is 22 or less.
In formula (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.

L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and -CH ₂ - contained in the saturated hydrocarbon group may be substituted with -O- or -CO-.

However, the total number of carbon atoms in L ^b4 and L ^b5 is 22 or less.
In formula (b1-3),
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.

L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and -CH ₂ - contained in the saturated hydrocarbon group may be substituted with -O- or -CO-.

However, the total number of carbon atoms in L ^b6 and L ^b7 is 23 or less.
In the groups represented by formulae (b1-1) to (b1-3), when --CH ₂ -- contained in the saturated hydrocarbon group is replaced with --O-- or --CO--, the number of carbon atoms before replacement is regarded as the number of carbon atoms of the saturated hydrocarbon group.

As the divalent saturated hydrocarbon group, the same divalent saturated hydrocarbon groups as those for ^L1 can be mentioned.
L ^b2 is preferably a single bond, a methylene group, -CH(CF ₃ )- or -C(CF ₃ ) ₂ -.

L ^b3 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b4 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms, in which a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom, and is more preferably a single bond, a methylene group, -CH(CF ₃ )-, or -C(CF ₃ ) ₂ -.

L ^b5 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b6 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.

L ^b7 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, in which a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and -CH ₂ - contained in the divalent saturated hydrocarbon group may be substituted with -O- or -CO-.

The divalent saturated hydrocarbon group represented by L ¹ in which --CH ₂ -- is replaced by --O-- or --CO-- is preferably a group represented by formula (b1-1) or formula (b1-3).
Examples of the group represented by formula (b1-1) include groups represented by formulas (b1-4) to (b1-8).

[In formula (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.

In formula (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and --CH ₂ -- contained in the divalent saturated hydrocarbon group may be replaced by --O-- or --CO--.

L ^b10 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxyl group.

However, the total number of carbon atoms in L ^b9 and L ^b10 is 20 or less.
In formula (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.

L ^b12 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.

However, the total number of carbon atoms in L ^b11 and L ^b12 is 21 or less.
In formula (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.

L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and --CH ₂ -- contained in the divalent saturated hydrocarbon group may be replaced by --O-- or --CO--.
L ^b15 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.

However, the total number of carbon atoms of L ^b13 to L ^b15 is 19 or less.
In formula (b1-8),
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and --CH ₂ -- contained in the divalent saturated hydrocarbon group may be replaced by --O-- or --CO--.

L ^b17 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.

However, the total number of carbon atoms of L ^b16 to L ^b18 is 19 or less.]
L ^b8 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b9 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.

L ^b10 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b11 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.

L ^b12 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b13 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b14 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.

L ^b15 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b16 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.

L ^b17 is preferably a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b18 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

Examples of the group represented by formula (b1-3) include the groups represented by formulas (b1-9) to (b1-11).

[In formula (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.

L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxyl group or an alkylcarbonyloxy group. -CH ₂ - contained in the alkylcarbonyloxy group may be replaced with -O- or -CO-, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxyl group.

However, the total number of carbon atoms in L ^b19 and L ^b20 is 23 or less.
In formula (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.

L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxyl group or an alkylcarbonyloxy group. -CH ₂ - contained in the alkylcarbonyloxy group may be replaced with -O- or -CO-, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxyl group.

However, the total number of carbon atoms of L ^b21 , L ^b22 and L ^b23 is 21 or less.
In formula (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.

L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxyl group or an alkylcarbonyloxy group. -CH ₂ - contained in the alkylcarbonyloxy group may be replaced with -O- or -CO-, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxyl group.

However, the total number of carbon atoms of L ^b24 , L ^b25 and L ^b26 is 21 or less.]
In addition, in the groups represented by formulae (b1-9) to (b1-11), when a hydrogen atom contained in the saturated hydrocarbon group is substituted with an alkylcarbonyloxy group, the number of carbon atoms before substitution is regarded as the number of carbon atoms of the saturated hydrocarbon group.

Examples of alkylcarbonyloxy groups include acetyloxy, propionyloxy, butyryloxy, cyclohexylcarbonyloxy, and adamantylcarbonyloxy groups.

Examples of the group represented by formula (b1-4) include the following:

Examples of the group represented by formula (b1-5) include the following:

Examples of the group represented by formula (b1-6) include the following:

Examples of the group represented by formula (b1-7) include the following:

Examples of the group represented by formula (b1-8) include the following:

Examples of the group represented by formula (b1-2) include the following:

Examples of the group represented by formula (b1-9) include the following:

Examples of the group represented by formula (b1-10) include the following:

Examples of the group represented by formula (b1-11) include the following:

Examples of the cyclic hydrocarbon group represented by ^Y1 include an alicyclic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic aromatic hydrocarbon group, or a combination thereof.
Examples of the alicyclic hydrocarbon group represented by ^Y1 in which —CH ₂ — is not replaced by —O—, —S—, —SO ₂ — or —CO— include groups represented by formulae (Y1) to (Y11) and formulae (Y36) to (Y38). * represents the bonding site with ^L1 .

When -CH ₂ - contained in the alicyclic hydrocarbon group represented by ^Y1 is replaced by -O-, -S-, -SO ₂ - or -CO-, the number may be 1 or 2 or more. Such groups may form an ether ring, ketone ring, lactone ring, sultone ring or acetal ring, and examples thereof include groups represented by formulae (Y12) to (Y35) and (Y39) to (Y43). -O- or -CO- in the groups represented by formulae (Y12) to (Y35) and (Y39) to (Y43) may be replaced by -S- or -SO ₂ -. * represents the bonding site with ^L1 .

The alicyclic hydrocarbon group represented by ^Y1 is preferably a group represented by any one of the formulas (Y1) to (Y20), (Y26), (Y27), (Y30), (Y31), (Y39) to (Y43), more preferably a group represented by the formula (Y11), (Y15), (Y16), (Y20), (Y26), (Y27), (Y30), (Y31), (Y39), (Y40), (Y42) or (Y43), and even more preferably a group represented by the formula (Y11), (Y15), (Y20), (Y26), (Y27), (Y30), (Y31), (Y39), (Y40), (Y42) or (Y43).

When the alicyclic hydrocarbon group represented by ^Y1 is a spirocyclic group having an oxygen atom such as those of formulae (Y28) to (Y35), (Y39), (Y40), (Y42) or (Y43), the alkanediyl group between the two oxygen atoms preferably has one or more fluorine atoms. Furthermore, among the alkanediyl groups contained in the ketal structure, it is preferable that the methylene group bonded to the oxygen atom is not substituted with a fluorine atom.

The alicyclic hydrocarbon group preferably has 3 to 24 carbon atoms, more preferably 3 to 20 carbon atoms, further preferably 3 to 18 carbon atoms, and even further preferably 3 to 16 carbon atoms.
Examples of the aromatic hydrocarbon group represented by ^Y1 include a phenyl group, a naphthyl group, a biphenyl group, an anthryl group, a phenanthryl group, a binaphthyl group, etc. The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 24, more preferably 6 to 20, still more preferably 6 to 18, still more preferably 6 to 14, and still more preferably 6 to 10.

Examples of the heterocyclic aromatic hydrocarbon group represented by ^Y1 include groups derived from a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, etc. The number of carbon atoms in the heterocyclic aromatic hydrocarbon group is preferably 4 to 9, and more preferably 4 to 8.

The aromatic hydrocarbon group or heterocyclic aromatic hydrocarbon group represented by ^Y1 is preferably a phenyl group, a naphthyl group, or a group derived from a furan ring or a thiophene ring, and more preferably a phenyl group.

When Y ¹ is a methyl group which may have a substituent, examples of the substituent on the methyl group include a halogen atom, a hydroxy group, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, a glycidyloxy group, a -(CH ₂ ) _ja -CO-O-R ^b1 group, or a -(CH ₂ ) _ja -O-CO-R ^b1 group (wherein R ^b1 represents an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof; ja represents an integer of 0 to 4; -CH ₂ - contained in the alkyl group and the alicyclic hydrocarbon group may be replaced by -O-, -SO ₂ - or -CO-; and a hydrogen atom contained in the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may be replaced by a hydroxy group or a fluorine atom).

When Y ¹ is a cyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, examples of the substituent on the cyclic hydrocarbon group include a halogen atom, a hydroxy group, an alkyl group having 1 to 16 carbon atoms which may be substituted with a hydroxy group (-CH ₂ - contained in the alkyl group may be replaced with -O- or -CO-), an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, a glycidyloxy group, a -(CH ₂ ) _ja -CO-O-R ^b1 group or a -(CH ₂ ) _ja -O-CO-R ^b1 group (wherein R ^b1 represents an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group combining these. ja represents an integer of 0 to 4. The -CH ₂ - contained in the alkyl group and the alicyclic hydrocarbon group may be replaced with -O-, -SO ₂ - or -CO-, and a hydrogen atom contained in the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may be replaced by a hydroxy group or a fluorine atom.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a norbornyl group, and an adamantyl group. The alicyclic hydrocarbon group may have a chain hydrocarbon group, and examples of the chain include a methylcyclohexyl group and a dimethylcyclohexyl group. The number of carbon atoms in the alicyclic hydrocarbon group is preferably 3 to 12, and more preferably 3 to 10.

Examples of aromatic hydrocarbon groups include aryl groups such as phenyl, naphthyl, anthryl, biphenyl, and phenanthryl. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and examples thereof include aromatic hydrocarbon groups having a chain hydrocarbon group with 1 to 18 carbon atoms (tolyl, xylyl, cumenyl, mesityl, p-methylphenyl, p-ethylphenyl, p-tert-butylphenyl, 2,6-diethylphenyl, 2-methyl-6-ethylphenyl, etc.) and aromatic hydrocarbon groups having an alicyclic hydrocarbon group with 3 to 18 carbon atoms (p-cyclohexylphenyl, p-adamantylphenyl, etc.). The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 14, and more preferably 6 to 10.

Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl, and dodecyl groups. The number of carbon atoms in the alkyl group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 4.

Examples of the alkyl group substituted with a hydroxy group include hydroxyalkyl groups such as a hydroxymethyl group and a hydroxyethyl group.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group, and a naphthylethyl group.

Examples of the alkyl group in which --CH ₂ -- is replaced by --O--, --SO ₂ --, --CO-- or the like include an alkoxy group, an alkylsulfonyl group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylcarbonyloxy group, or a combination thereof.

Examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy, and dodecyloxy groups. The number of carbon atoms in the alkoxy group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 4.

Examples of the alkylsulfonyl group include a methylsulfonyl group, an ethylsulfonyl group, and a propylsulfonyl group. The number of carbon atoms in the alkylsulfonyl group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 4.

Examples of alkoxycarbonyl groups include methoxycarbonyl groups, ethoxycarbonyl groups, and butoxycarbonyl groups. The number of carbon atoms in the alkoxycarbonyl group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 to 4.

Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group. The number of carbon atoms in the alkylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 to 4.

Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, and a butyryloxy group. The number of carbon atoms in the alkylcarbonyloxy group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 to 4.

Examples of the combined groups include a group that combines an alkoxy group with an alkyl group, a group that combines an alkoxy group with an alkoxy group, a group that combines an alkoxy group with an alkylcarbonyl group, and a group that combines an alkoxy group with an alkylcarbonyloxy group.

Examples of groups that combine an alkoxy group and an alkyl group include alkoxyalkyl groups such as a methoxymethyl group, a methoxyethyl group, an ethoxyethyl group, and an ethoxymethyl group. The number of carbon atoms in the alkoxyalkyl group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 to 4.

Examples of groups that combine alkoxy groups include alkoxyalkoxy groups such as methoxymethoxy, methoxyethoxy, ethoxymethoxy, and ethoxyethoxy. The number of carbon atoms in the alkoxyalkoxy group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 to 4.

Examples of groups that combine an alkoxy group and an alkylcarbonyl group include alkoxyalkylcarbonyl groups such as methoxyacetyl, methoxypropionyl, ethoxyacetyl, and ethoxypropionyl. The number of carbon atoms in the alkoxyalkylcarbonyl group is preferably 3 to 13, more preferably 3 to 7, and even more preferably 3 to 5.

Examples of groups that combine an alkoxy group and an alkylcarbonyloxy group include alkoxyalkylcarbonyloxy groups such as methoxyacetyloxy, methoxypropionyloxy, ethoxyacetyloxy, and ethoxypropionyloxy. The number of carbon atoms in the alkoxyalkylcarbonyloxy group is preferably 3 to 13, more preferably 3 to 7, and even more preferably 3 to 5.

Examples of the alicyclic hydrocarbon group in which --CH ₂ -- is replaced by --O--, --SO ₂ --, --CO-- or the like include groups represented by formulae (Y12) to (Y35) and formulae (Y39) to (Y43).

The cyclic hydrocarbon group for Y ¹ (wherein —CH ₂ — may be replaced by —O—, —CO—, —S— or —SO ₂ —) is preferably an alicyclic hydrocarbon group having 3 to 24 carbon atoms (wherein —CH ₂ — may be replaced by —O—, —CO—, —S— or —SO ₂ —) or an aromatic hydrocarbon group having 6 to 24 carbon atoms, more preferably an alicyclic hydrocarbon group having 3 to 20 carbon atoms (wherein —CH ₂ — may be replaced by —O—, —CO—, —S— or —SO 2 —) or an aromatic hydrocarbon group having 6 to 20 carbon atoms, and more preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms (wherein —CH ₂ — may be replaced by —O—, —CO—, —S— or —SO _{2 —} ). - may be substituted. ) or an aromatic hydrocarbon group having 6 to 18 carbon atoms is more preferred. Specifically, it is preferably a group represented by any one of formulas (w1-1) to (w1-32), more preferably a group represented by any one of formulas (w1-1) to (w1-6) and (w1-12) to (w1-30), and even more preferably a group represented by any one of formulas (w1-1) to (w1-3), (w1-15) to (w1-17), (w1-22), (w1-25) and (w1-27) to (w1-29). Here, the cyclic hydrocarbon group may have a substituent.

[In formulas (w1-1) to (w1-32),
The --CH ₂ -- contained in the group may be replaced by --O--, --S--, --CO-- or --SO ₂ --. The bonding site may be at any position.]
Y ¹ is preferably an alicyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent or an aromatic hydrocarbon group having 6 to 24 carbon atoms which may have a substituent, more preferably an alicyclic hydrocarbon group having 3 to 20 carbon atoms which may have a substituent or an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent, even more preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent or an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, and even more preferably a cycloalkyl group having 5 or 6 carbon atoms, a norbornyl group, an adamantyl group, a norbornane lactone group, an adamantane lactone group, an alicyclic hydrocarbon group in which a cycloalkyl group having 5 or 6 carbon atoms and a cycloalkyl group having 5 to 8 carbon atoms are bonded together in a spiro bond, an alicyclic hydrocarbon group in which a norbornyl group and a cycloalkyl group having 5 to 8 carbon atoms are bonded together in a spiro bond, an alicyclic hydrocarbon group in which an adamantyl group and a cycloalkyl group having 5 to 8 carbon atoms are bonded together in a spiro bond, or a phenyl group. Here, the alicyclic hydrocarbon group, the cycloalkyl group, the norbornyl group, the adamantyl group, the norbornane lactone group and the adamantane lactone group may each have a substituent, and -CH ₂ - contained in the alicyclic hydrocarbon group, the cycloalkyl group, the norbornyl group and the adamantyl group may each be replaced by -O-, -S-, -SO ₂ - or -CO-.

Specific examples of ^Y1 include the following.

Among them, ^Y1 is preferably an adamantyl group, a hydroxyadamantyl group, an oxoadamantyl group, a norbornane lactone group, a phenyl group, a group containing these, or a group represented by formula (Y42), formula (Y100) to formula (Y114), or formula (Y134) to formula (Y139), and particularly preferably a hydroxyadamantyl group, an oxoadamantyl group, a group containing these, or a group represented by formula (Y42), formula (Y100) to formula (Y114), or formula (Y134) to formula (Y139).

As the anion represented by formula (I-A), anions represented by formulas (I-A-1) to (I-A-85) (hereinafter, may be referred to as "anion (I-A-1)" depending on the formula number) are preferred, and anions represented by any of formulas (I-A-1) to (I-A-4), (I-A-9), (I-A-10), (I-A-24) to (I-A-33), (I-A-36) to (I-A-40), and (I-A-47) to (I-A-85) are more preferred.

Here, R ⁱ² to R ⁱ⁷ are each independently, for example, an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group. ^{R i8} is, for example, a chain hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or a group formed by combining these, more preferably a methyl group, an ethyl group, a cyclohexyl group, or an adamantyl group. L ^A41 is a single bond or an alkanediyl group having 1 to 4 carbon atoms. Q ¹ and Q ² are as defined above.

Specific examples of the anion represented by formula (IA) include the anions described in JP-A-2010-204646.
Preferable examples of the anion represented by formula (IA) include the anions represented by formulas (Ia-1) to (Ia-70).

Among these, anions represented by any of formulas (I-a-1) to (I-a-4), (I-a-7) to (I-a-11), (I-a-14) to (I-a-30), and (I-a-35) to (I-a-68) are preferred.

[In formula (IB),
m21 represents an integer of 1 to 5, and when m21 is 2 or greater, the groups in the parentheses may be the same or different.

R ²¹ represents a hydrocarbon group having 3 to 48 carbon atoms, including a cyclic hydrocarbon group having 3 to 18 carbon atoms, the cyclic hydrocarbon group may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-.

R ²² represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and --CH ₂ -- contained in the alkyl group may be replaced by --O-- or --CO--.
m22 represents an integer of 0 to 4, and when m22 is 2 or more, the multiple R ²² may be the same or different.
In formula (IB), examples of the hydrocarbon group containing a cyclic hydrocarbon group in R ²¹ include cyclic hydrocarbon groups such as monocyclic or polycyclic alicyclic hydrocarbon groups and aromatic hydrocarbon groups, or groups combining these, and groups in which cyclic hydrocarbon groups such as monocyclic or polycyclic alicyclic hydrocarbon groups and aromatic hydrocarbon groups are arbitrarily combined with chain hydrocarbon groups (alkyl groups, alkenyl groups, alkynyl groups, etc.). The number of carbon atoms in the cyclic hydrocarbon group in R ²¹ is, for example, 3 to 24, preferably 3 to 20, more preferably 3 to 18, even more preferably 3 to 16, and even more preferably 5 to 16. The total number of carbon atoms in the hydrocarbon group containing a cyclic hydrocarbon group in R ²¹ is, for example, 3 to 48, preferably 3 to 40, more preferably 3 to 36, even more preferably 3 to 30, even more preferably 3 to 24, even more preferably 3 to 18, and even more preferably 3 to 16.

Alicyclic hydrocarbon groups may be monocyclic, polycyclic, or spirocyclic, and may be saturated or unsaturated. Examples of alicyclic hydrocarbon groups include monocyclic cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and cyclododecyl, and polycyclic cycloalkyl groups such as decahydronaphthyl, norbornyl, and adamantyl.

Specific examples of alicyclic hydrocarbon groups include the groups shown below. The binding site can be any position.

More specifically, examples of alicyclic hydrocarbon groups include the groups shown below. * indicates a bonding site.

The alicyclic hydrocarbon group preferably has 3 to 24 carbon atoms, more preferably 3 to 18 carbon atoms, even more preferably 3 to 16 carbon atoms, and even more preferably 5 to 16 carbon atoms.
Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a naphthyl group, a biphenyl group, an anthryl group, a phenanthryl group, a binaphthyl group, etc. The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 24, more preferably 6 to 18, even more preferably 6 to 14, and even more preferably 6 to 10.

Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups.

Examples of alkenyl groups include ethenyl, propenyl, isopropenyl, butenyl, isobutenyl, tert-butenyl, pentenyl, hexenyl, heptenyl, octenyl, isooctenyl, and nonenyl groups.

Examples of alkynyl groups include ethynyl, propynyl, isopropynyl, butynyl, isobutynyl, tert-butynyl, pentynyl, hexynyl, octynyl, and nonynyl groups.

The number of carbon atoms in the chain hydrocarbon group is preferably 1 to 24, more preferably 1 to 18, even more preferably 1 to 12, even more preferably 1 to 8, even more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

The combined groups are:
Examples of such groups include a combination of an alicyclic hydrocarbon group and an aromatic hydrocarbon group, a combination of an alicyclic hydrocarbon group and an open chain hydrocarbon group, a combination of an aromatic hydrocarbon group and an open chain hydrocarbon group, a combination of an alicyclic hydrocarbon group, an aromatic hydrocarbon group and an open chain hydrocarbon group, etc. Here, -CH ₂ - contained in the combined group may be replaced by -O-, -S-, -CO- or -SO ₂ -.

In addition, in the combination, two or more types of alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and chain hydrocarbon groups may be combined. In addition, any of the groups may be bonded to an oxygen atom. In addition, the above groups may contain groups with different valences (alkanediyl groups, alkanetriyl groups, cycloalkanediyl groups, cycloalkanetriyl groups, etc.).

Specific examples of the combined groups include:
Alicyclic hydrocarbon group-chain hydrocarbon group-*, such as adamantylmethyl group, adamantylethyl group, cyclohexylmethyl group, cyclohexylethyl group, etc. (-CH ₂ - contained in the chain hydrocarbon group and the alicyclic hydrocarbon group may be replaced by -O-, -S-, -CO- or -SO ₂ -).
Chain hydrocarbon group-alicyclic hydrocarbon group-*, such as a methyladamantyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, etc. (-CH ₂ - contained in the chain hydrocarbon group and the alicyclic hydrocarbon group may be replaced with -O-, -S-, -CO- or -SO ₂ -).
a chain hydrocarbon group-aromatic hydrocarbon group-*, such as a tolyl group or a xylyl group ( _-CH2- contained in the chain hydrocarbon group may be replaced by -O-, -S-, -CO- or _-SO2- );
Chain hydrocarbon group-alicyclic hydrocarbon group-chain hydrocarbon group-*, such as methylcyclohexylmethyl group ( _-CH2- contained in the chain hydrocarbon group and the alicyclic hydrocarbon group may be replaced by -O-, -S-, -CO- or _-SO2- ),
Aromatic hydrocarbon group-chain hydrocarbon group-*, such as a benzyl group or a phenethyl group ( _-CH2- contained in the chain hydrocarbon group may be replaced by -O-, -S-, -CO- or _-SO2- ),
a chain hydrocarbon group such as a tolylmethyl group-aromatic hydrocarbon group-chain hydrocarbon group-* (-CH ₂ - contained in the chain hydrocarbon group may be replaced by -O-, -S-, -CO- or -SO ₂ -);
Aromatic hydrocarbon group-alicyclic hydrocarbon group-*, such as a phenyladamantyl group ( _-CH2- contained in the alicyclic hydrocarbon group may be replaced by -O-, -S-, -CO- or _-SO2- ),
Alicyclic hydrocarbon group-aromatic hydrocarbon group-*, such as a cyclohexylphenyl group or an adamantylphenyl group ( _-CH2- contained in the alicyclic hydrocarbon group may be replaced by -O-, -S-, -CO- or _-SO2- ),
A chain hydrocarbon group-alicyclic hydrocarbon group-aromatic hydrocarbon group-*, such as a methylcyclohexylphenyl group or a dimethylcyclohexylphenyl group ( _-CH2- contained in the chain hydrocarbon group and the alicyclic hydrocarbon group may be replaced by -O-, -S-, -CO- or _-SO2- ),
A chain hydrocarbon group-aromatic hydrocarbon group-alicyclic hydrocarbon group-*, such as a methylphenylcyclohexyl group or a dimethylphenylcyclohexyl group ( _-CH2- contained in the chain hydrocarbon group and the alicyclic hydrocarbon group may be replaced by -O-, -S-, -CO- or _-SO2- ),
Alicyclic hydrocarbon group-chain hydrocarbon group-aromatic hydrocarbon group-*, such as a cyclohexylmethylphenyl group or a cyclohexylethylphenyl group ( _-CH2- contained in the chain hydrocarbon group and the alicyclic hydrocarbon group may be replaced by -O-, -S-, -CO- or _-SO2- ),
Aromatic hydrocarbon group-chain hydrocarbon group-alicyclic hydrocarbon group-*, such as a phenylmethylcyclohexyl group or a phenylethylcyclohexyl group (-CH ₂ - contained in the chain hydrocarbon group and the alicyclic hydrocarbon group may be replaced with -O-, -S-, -CO- or -SO ₂ -);
Alicyclic hydrocarbon group-aromatic hydrocarbon group-chain hydrocarbon group-*, such as a cyclohexylphenylmethyl group or a cyclohexylphenylethyl group ( _-CH2- contained in the chain hydrocarbon group and the alicyclic hydrocarbon group may be replaced by -O-, -S-, -CO- or _-SO2- ),
Aromatic hydrocarbon group-alicyclic hydrocarbon group-chain hydrocarbon group-*, such as a phenylcyclohexylmethyl group or a phenylcyclohexylethyl group ( _-CH2- contained in the chain hydrocarbon group and the alicyclic hydrocarbon group may be replaced with -O-, -S-, -CO- or _-SO2- ),
Here, * represents the bonding site with an oxygen atom.

When —CH ₂ — contained in the hydrocarbon group represented by R ²¹ is replaced by —O—, —S—, —CO— or —SO ₂ —, the number of carbon atoms before the replacement is regarded as the total number of carbon atoms in the hydrocarbon group. In addition, the number may be 1 or 2 or more.

Examples of groups in which -CH ₂ - in a hydrocarbon group is replaced by -O-, -S-, -CO- or -SO ₂ - include a hydroxy group (a group in which -CH ₂ - in a methyl group is replaced by -O-), a thiol group (a group in which -CH ₂ - in a methyl group is replaced by -S-), a carboxy group (a group in which -CH ₂ -CH ₂ - in an ethyl group is replaced by -O-CO-), an alkoxy group (a group in which -CH ₂ - at any position in an alkyl group is replaced by -O-), an alkylthio group (a group in which -CH ₂ - at any position in an alkyl group is replaced by -S-), an alkoxycarbonyl group (a group in which -CH ₂ -CH ₂ - at any position in an alkyl group is replaced by -O-CO-), an alkylcarbonyl group (a group in which -CH ₂ - - is replaced with -CO-), an alkylsulfonyl group (a group in which -CH ₂ - at any position contained in an alkyl group is replaced with -SO ₂ -), an alkylcarbonyloxy group (a group in which -CH ₂ -CH ₂ - at any position contained in an alkyl group is replaced with -CO-O-), an oxy group (a group in which -CH ₂ - contained in a methylene group is replaced with -O-), a carbonyl group (a group in which -CH ₂ - contained in a methylene group is replaced with -CO-), a thio group (a group in which -CH ₂ - contained in a methylene group is replaced with -S-), a sulfonyl group (a group in which -CH ₂ - contained in a methylene group is replaced with -SO ₂ -), an alkanediyloxy group (a group in which -CH 2 - at any position contained in an alkanediyl group is replaced with -SO ₂ -), - is replaced by -O-), an alkanediyloxycarbonyl group (a group in which -CH ₂ -CH ₂ - at any position contained in an alkanediyl group is replaced by -O-CO-), an alkanediylcarbonyl group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced by -CO-), an alkanediylcarbonyloxy group (a group in which -CH ₂ -CH ₂ - at any position contained in an alkanediyl group is replaced by -CO-O-), an alkanediylthio group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced by -S-), an alkanediylsulfonyl group (a group in which -CH ₂ - at any position contained in an alkanediyl group is replaced by -SO ₂ -substituted), cycloalkoxy groups, cycloalkylalkoxy groups, alkoxycarbonyloxy groups, aromatic hydrocarbon group-carbonyloxy groups, aromatic hydrocarbon group-carbonyl groups, aromatic hydrocarbon group-oxy groups, and combinations of two or more of these groups.

Examples of alkoxy groups include alkoxy groups having 1 to 17 carbon atoms, such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, and undecyloxy. The number of carbon atoms in the alkoxy group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of alkylthio groups include alkylthio groups having 1 to 17 carbon atoms, such as methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, octylthio, 2-ethylhexylthio, nonylthio, decylthio, and undecylthio. The number of carbon atoms in the alkylthio group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

The alkoxycarbonyl group, alkylcarbonyl group, and alkylcarbonyloxy group refer to groups in which a carbonyl group or carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group.

Examples of alkoxycarbonyl groups include alkoxycarbonyl groups having 2 to 17 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, and butoxycarbonyl groups. Examples of alkylcarbonyl groups include alkylcarbonyl groups having 2 to 18 carbon atoms, such as acetyl, propionyl, and butyryl groups. Examples of alkylcarbonyloxy groups include alkylcarbonyloxy groups having 2 to 17 carbon atoms, such as acetyloxy, propionyloxy, and butyryloxy groups. The number of carbon atoms in the alkoxycarbonyl group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkylcarbonyloxy group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3.

Examples of alkylsulfonyl groups include alkylsulfonyl groups having 1 to 17 carbon atoms, such as methylsulfonyl, ethylsulfonyl, propylsulfonyl, butylsulfonyl, pentylsulfonyl, hexylsulfonyl, octylsulfonyl, 2-ethylhexylsulfonyl, nonylsulfonyl, decylsulfonyl, and undecylsulfonyl groups. The number of carbon atoms in the alkylsulfonyl group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of alkanediyloxy groups include alkanediyloxy groups having 1 to 17 carbon atoms, such as methyleneoxy groups, ethyleneoxy groups, propanediyloxy groups, butanediyloxy groups, and pentanediyloxy groups. The number of carbon atoms in the alkanediyloxy group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of the alkanediyloxycarbonyl group include alkanediyloxycarbonyl groups having 2 to 17 carbon atoms, such as methyleneoxycarbonyl group, ethyleneoxycarbonyl group, propanediyloxycarbonyl group, butanediyloxycarbonyl group, etc. Examples of the alkanediylcarbonyl group include alkanediylcarbonyl groups having 2 to 18 carbon atoms, such as methylenecarbonyl group, ethylenecarbonyl group, propanediylcarbonyl group, butanediylcarbonyl group, pentanediylcarbonyl group, etc. Examples of the alkanediylcarbonyloxy group include alkanediylcarbonyloxy groups having 2 to 17 carbon atoms, such as methylenecarbonyloxy group, ethylenecarbonyloxy group, propanediylcarbonyloxy group, butanediylcarbonyloxy group, etc. The number of carbon atoms in the alkanediyloxycarbonyl group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkanediylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkanediylcarbonyloxy group is preferably 2 to 11, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3.

Examples of alkanediylthio groups include alkanediylthio groups having 1 to 17 carbon atoms, such as methylenethio groups, ethylenethio groups, and propylenethio groups. The number of carbon atoms in the alkanediylthio group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of alkanediylsulfonyl groups include alkanediylsulfonyl groups having 1 to 17 carbon atoms, such as methylenesulfonyl groups, ethylenesulfonyl groups, and propylenesulfonyl groups. The number of carbon atoms in the alkanediylsulfonyl group is preferably 1 to 11, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

Examples of cycloalkoxy groups include cycloalkoxy groups having 3 to 17 carbon atoms, such as cyclohexyloxy groups. Examples of cycloalkylalkoxy groups include cycloalkylalkoxy groups having 4 to 17 carbon atoms, such as cyclohexylmethoxy groups. Examples of alkoxycarbonyloxy groups include alkoxycarbonyloxy groups having 2 to 16 carbon atoms, such as butoxycarbonyloxy groups. Examples of aromatic hydrocarbon group-carbonyloxy groups include aromatic hydrocarbon group-carbonyloxy groups having 7 to 17 carbon atoms, such as benzoyloxy groups. Examples of aromatic hydrocarbon group-carbonyl groups include aromatic hydrocarbon group-carbonyl groups having 7 to 18 carbon atoms, such as benzoyl groups. Examples of aromatic hydrocarbon group-oxy groups include aromatic hydrocarbon group-oxy groups having 6 to 17 carbon atoms, such as phenyloxy groups.

Examples of groups in which --CH ₂ -- contained in an alicyclic hydrocarbon group is replaced by --O--, --S--, --CO-- or --SO ₂ -- include the groups shown below. --O-- or --CO-- in the groups shown below may be replaced by --S-- or --SO ₂ --. The bonding site may be at any position.

More specifically, examples of the group in which --CH ₂ -- contained in the alicyclic hydrocarbon group is replaced by --O--, --S--, --CO-- or --SO ₂ -- include the groups shown below, in which * represents a bonding site.

Examples of the substituent that the cyclic hydrocarbon group may have include a halogen atom, a cyano group, and an alkyl group having 1 to 12 carbon atoms ( _-CH2- contained in the alkyl group may be replaced with -O-, -S-, -CO- or _-SO2- ). When the cyclic hydrocarbon group has a substituent, the substituent is not included in the total number of carbon atoms of the hydrocarbon group including the cyclic hydrocarbon group in ^R21 .

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a nonyl group, etc. The number of carbon atoms in the alkyl group is preferably 1 to 10, more preferably 1 to 9, still more preferably 1 to 8, even more preferably 1 to 6, still more preferably 1 to 4, and still more preferably 1 to 3.

When --CH ₂ -- contained in an alkyl group is replaced with --O--, --S--, --CO-- or --SO ₂ -- as a substituent, the number of carbon atoms before replacement is regarded as the total number of carbon atoms in the alkyl group. Examples of the substituted group include a hydroxy group (a group in which -CH ₂ - in a methyl group is replaced with -O-), a carboxy group (a group in which -CH ₂ -CH ₂ - in an ethyl group is replaced with -O-CO-), an alkoxy group (a group in which -CH ₂ - at any position in an alkyl group is replaced with -O-), an alkoxycarbonyl group (a group in which -CH ₂ -CH ₂ - at any position in an alkyl group is replaced with -O-CO-), an alkylcarbonyl group (a group in which -CH ₂ - at any position in an alkyl group is replaced with -CO-), an alkylcarbonyloxy group (a group in which -CH ₂ -CH ₂ - at any position in an alkyl group is replaced with -CO-O-), and groups combining two or more of these groups.

Examples of alkoxy groups include alkoxy groups having 1 to 11 carbon atoms, such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, and undecyloxy. The number of carbon atoms in the alkoxy group is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3.

The alkoxycarbonyl group, alkylcarbonyl group, and alkylcarbonyloxy group refer to groups in which a carbonyl group or carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group.

The alkoxycarbonyl group includes an alkoxycarbonyl group having 2 to 11 carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, and a butoxycarbonyl group. The alkylcarbonyl group includes an alkylcarbonyl group having 2 to 12 carbon atoms, such as an acetyl group, a propionyl group, and a butyryl group. The alkylcarbonyloxy group includes an alkylcarbonyloxy group having 2 to 11 carbon atoms, such as an acetyloxy group, a propionyloxy group, and a butyryloxy group. The number of carbon atoms in the alkoxycarbonyl group is preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkylcarbonyl group is preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkylcarbonyloxy group is preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3.

The cyclic hydrocarbon group may have one substituent or multiple substituents.
The substituent that the cyclic hydrocarbon group may have is preferably a halogen atom or an alkyl group having 1 to 6 carbon atoms (-CH ₂ - contained in the alkyl group may be replaced with -O-, -S-, -CO- or -SO ₂ -), more preferably a fluorine atom, an iodine atom or an alkyl group having 1 to 4 carbon atoms (-CH ₂ - contained in the alkyl group may be replaced with -O-, -S-, -CO- or -SO ₂ -), even more preferably a fluorine atom, an iodine atom, a hydroxy group, an alkoxy group having 1 to 3 carbon atoms or an alkyl group having 1 to 4 carbon atoms, and still more preferably a fluorine atom, an iodine atom, a hydroxy group or an alkyl group having 1 to 4 carbon atoms.

The cyclic hydrocarbon group (which may have a substituent, and the --CH ₂ -- contained in the cyclic hydrocarbon group may be replaced by --O--, --S--, --SO ₂ -- or --CO--) is
It is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms (the alicyclic hydrocarbon group may have a substituent, and —CH ₂ — contained in the alicyclic hydrocarbon group may be replaced by —O—, —S—, —SO ₂ — or —CO—), or an aromatic hydrocarbon group having 6 to 18 carbon atoms (the aromatic hydrocarbon group may have a substituent),
More preferably, it is an alicyclic hydrocarbon group having 3 to 18 carbon atoms (the alicyclic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom, and _-CH2- contained in the alicyclic hydrocarbon group may be replaced by -O-, -S-, _-SO2- or -CO-), or an aromatic hydrocarbon group having 6 to 18 carbon atoms (the aromatic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom),
More preferably, it is an alicyclic hydrocarbon group having 5 to 16 carbon atoms (the alicyclic hydrocarbon group may have one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom, and _-CH2- contained in the alicyclic hydrocarbon group may be replaced by -O-, -S-, _-SO2- or -CO-).

Examples of the hydrocarbon group having 3 to 48 carbon atoms and containing a cyclic hydrocarbon group represented by R ²¹ (the cyclic hydrocarbon group may have a substituent, and the —CH ₂ — contained in the hydrocarbon group may be replaced by —O—, —S—, —SO ₂ — or —CO—) include:
It is preferably a hydrocarbon group having 3 to 48 carbon atoms including an alicyclic hydrocarbon group having 3 to 18 carbon atoms (the alicyclic hydrocarbon group may have a substituent, and the -CH ₂ - included in the hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-), or a hydrocarbon group having 6 to 48 carbon atoms including an aromatic hydrocarbon group having 6 to 18 carbon atoms (the aromatic hydrocarbon group may have a substituent, and the -CH ₂ - included in the hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-),
more preferably a hydrocarbon group having 3 to 48 carbon atoms including an alicyclic hydrocarbon group having 3 to 18 carbon atoms (the alicyclic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom, and the -CH ₂ - included in the hydrocarbon group may be replaced with -O-, -S-, -SO ₂ - or -CO-), or a hydrocarbon group having 6 to 48 carbon atoms including an aromatic hydrocarbon group having 6 to 18 carbon atoms (the aromatic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom, and the -CH ₂ - included in the hydrocarbon group may be replaced with -O-, -S-, -SO ₂ - or -CO-);
an alicyclic hydrocarbon group having 3 to 18 carbon atoms (the alicyclic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom, and a fluorine atom, and the -CH ₂ - contained in the alicyclic hydrocarbon group may be replaced with -O-, -S-, -SO ₂ -, or -CO-); a group combining an alicyclic hydrocarbon group having 3 to 18 carbon atoms with a chain hydrocarbon group having 1 to 6 carbon atoms (the alicyclic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom, and a fluorine atom, and the -CH ₂ - contained in the combined group may be replaced with -O-, -S-, -SO ₂ -, or -CO-); - or -CO-), an aromatic hydrocarbon group having 6 to 18 carbon atoms (the aromatic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom), or a group combining an aromatic hydrocarbon group having 6 to 18 carbon atoms with a chain hydrocarbon group having 1 to 6 carbon atoms (the aromatic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom, and the -CH ₂ - contained in the combined group may be replaced by -O-, -S-, -SO ₂ - or -CO-),
It is even more preferable that the alkyl group is an alicyclic hydrocarbon group having 5 to 16 carbon atoms (the alicyclic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom, and the -CH ₂ - contained in the alicyclic hydrocarbon group may be replaced with -O-, -S-, -SO ₂ - or -CO-), or a group consisting of an alicyclic hydrocarbon group having 5 to 16 carbon atoms and a chain hydrocarbon group having 1 to 4 carbon atoms (the alicyclic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom, and the -CH ₂ - contained in the combined group may be replaced with -O-, -S-, -SO ₂ - or -CO-).

Examples of the hydrocarbon group having 3 to 48 carbon atoms and containing a cyclic hydrocarbon group represented by R ²¹ (the cyclic hydrocarbon group may have a substituent, and the —CH ₂ — contained in the hydrocarbon group may be replaced by —O—, —S—, —SO ₂ — or —CO—) include:
It is also preferable that W ²¹ -L ²¹ -* (W ²¹ represents a cyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and -CH ₂ - contained in the cyclic hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-; L ²¹ represents a single bond or a chain hydrocarbon group having 1 to 6 carbon atoms, and -CH ₂ - contained in the chain hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-; * represents a bonding site with an oxygen atom).

Examples of the cyclic hydrocarbon group for W ²¹ , the substituent that W ²¹ may have, and the chain hydrocarbon group for L ²¹ include the same groups as those mentioned above.
W ²¹ is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms (the alicyclic hydrocarbon group may have a substituent, and the -CH ₂ - contained in the alicyclic hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-), or an aromatic hydrocarbon group having 6 to 18 carbon atoms (the aromatic hydrocarbon group may have a substituent), and is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms (the alicyclic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, an iodine atom and a fluorine atom, and the -CH ₂ - contained in the alicyclic hydrocarbon group is replaced by -O-, -S-, -SO ₂ - or -CO-). - or -CO-), or an aromatic hydrocarbon group having 6 to 18 carbon atoms (the aromatic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom), and even more preferably an alicyclic hydrocarbon group having 5 to 16 carbon atoms (the alicyclic hydrocarbon group may have one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, an iodine atom and a fluorine atom, and the -CH ₂ - contained in the alicyclic hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-).

L ²¹ is preferably a single bond or a chain hydrocarbon group having 1 to 6 carbon atoms (-CH ₂ - contained in the chain hydrocarbon group may be replaced by -O- or -CO-), more preferably a single bond or a chain hydrocarbon group having 1 to 4 carbon atoms (-CH ₂ - contained in the chain hydrocarbon group may be replaced by -O- or -CO-), and even more preferably a single bond or a chain hydrocarbon group having 1 to 3 carbon atoms.

m21 is an integer of 1 to 5, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, still more preferably 1 or 2, and even more preferably 2. When m21 is 1 or 2, the following structure, which is m-substituted with respect to SO ₃ ^-, is preferable.

In the above formula, R ^21' has the same definition as R ²¹ described above, and may be the same as or different from R ²¹ .
Examples of the alkyl group having 1 to 6 carbon atoms for R ²² include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a hexyl group. The number of carbon atoms in the alkyl group is preferably 1 to 4, and more preferably 1 to 3.

Examples of the halogen atom for R ²² include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Each R ²² is independently preferably a halogen atom or an alkyl group having 1 to 4 carbon atoms (wherein the --CH ₂ -- contained in the alkyl group may be replaced by --O-- or --CO--), more preferably a fluorine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms (wherein the --CH ₂ -- contained in the alkyl group may be replaced by --O-- or --CO--), and even more preferably a fluorine atom, an iodine atom, a hydroxy group, a methoxy group or a methyl group.

m22 is an integer of 0 to 4, preferably an integer of 0 to 3, and more preferably an integer of 0 to 2. In one embodiment, m22 is preferably 0. In another embodiment, m22 is preferably 1 or 2. When m22 is 1, R ²² is preferably a halogen atom, and more preferably R ²² is a fluorine atom or iodine atom. When m22 is 2, it is preferable that one of R 22 is a halogen atom and the other is a halogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably that one ^of R ²² is a fluorine atom or iodine atom and the other is a fluorine atom, iodine atom, or an alkyl group having 1 to 3 carbon atoms.

Examples of the anion (IB) include the following anions. Among them, the anions represented by formulas (IB-1) to (IB-20) are preferred, and the anions represented by formulas (IB-1) to (IB-11) and (IB-16) to (IB-20) are more preferred.

When AI ⁻ is a sulfonylimide anion, examples of the sulfonylimide anion include the following.

When AI ⁻ is a sulfonylimide anion, examples of the sulfonylmethide anion include the following:

Specific examples of the salt (I) include salts of any combination of the above-mentioned cations and anions. Specific examples of the salt (I) are shown in the table below.
In the following table, each symbol represents the symbol attached to the structure representing the above-mentioned anion or cation, and "-" indicates that the salt (I) corresponds to the anion (I) or cation (I). For example, the salt (I-1) is a salt consisting of the anion represented by the formula (I-a-1) and the cation represented by the formula (I-c-1), the salt (I-2) is a salt consisting of the anion represented by the formula (I-a-2) and the cation represented by the formula (I-c-1), and the salt (I-41) is a salt consisting of the anion represented by the formula (I-a-1) and the cation represented by the formula (I-c-2).

Among them, the salt (I) is a combination of an anion represented by any one of formulas (I-a-1) to (I-a-4), (I-a-7) to (I-a-11), (I-a-14) to (I-a-30), (I-a-35) to (I-a-68), and (I-B-1) to (I-B-20) and a cation represented by any one of formulas (I-c-1) to (I-c-252). Specifically, salts obtained by mixing the above-mentioned salts are preferred, and specifically, salts (I-1) to (I-4), salts (I-7) to (I-11), salts (I-14) to (I-30), salts (I-35) to (I-40), salts (I-41) to (I-44), salts (I-47) to (I-51), salts (I-54) to (I-70), salts (I-75) to (I-80), salts (I-81) to (I-84), salts (I-85) to (I-86), salts (I-87) to (I-89), salts (I-90) to (I-91), salts (I-92) to (I-93), salts (I-94) to (I-95), salts (I-96) to (I-97), salts (I-98) to (I-99), salts (I-100) to (I-103), salts (I-104) to (I-105), salts (I-106) to (I-107), salts (I-109) to (I-210), salts (I-220) to (I-221), salts (I-109) to (I-230), salts (I-110) to (I-231), salts (I-111) to (I-232), salts (I-112) to (I-233), salts (I-113) to (I-234), salts (I-114) to (I-235), salts (I-115) to (I-236), salts (I-116) to (I-237), salts (I-117) to (I-238), salts (I-118) to (I-240), -87) to salt (I-91), salt (I-94) to salt (I-110), salt (I-115) to salt (I-120), salt (I-121) to salt (I-124), salt (I-127) to salt (I-131), salt (I-134) to salt (I-150), salt (I-155) to salt (I-160), salt (I-161) to salt (I-164), salt (I-167) to salt (I-171), salt (I- 174) to salt (I-190), salt (I-195) to salt (I-200), salt (I-201) to salt (I-204), salt (I-207) to salt (I-211), salt (I-214) to salt (I-230), salt (I-235) to salt (I-240), salt (I-241) to salt (I-244), salt (I-247) to salt (I-251), salt (I-254) to salt (I-270), salt ( Salt (I-275) to salt (I-280), salt (I-281) to salt (I-284), salt (I-287) to salt (I-291), salt (I-294) to salt (I-310), salt (I-315) to salt (I-320), salt (I-321) to salt (I-324), salt (I-327) to salt (I-331), salt (I-334) to salt (I-350), salt (I-355) to salt (I-360), Salt (I-361) to salt (I-364), salt (I-367) to salt (I-371), salt (I-374) to salt (I-390), salt (I-395) to salt (I-400), salt (I-401) to salt (I-404), salt (I-407) to salt (I-411), salt (I-414) to salt (I-430), salt (I-435) to salt (I-440), salt (I-441) to salt (I-444) ), salt (I-447) to salt (I-451), salt (I-454) to salt (I-470), salt (I-475) to salt (I-480), salt (I-481) to salt (I-484), salt (I-487) to salt (I-491), salt (I-494) to salt (I-510), salt (I-515) to salt (I-520), salt (I-521) to salt (I-524), salt (I-527) to salt (I-5 31), salt (I-534) to salt (I-550), salt (I-555) to salt (I-560), salt (I-561) to salt (I-564), salt (I-567) to salt (I-571), salt (I-574) to salt (I-590), salt (I-595) to salt (I-600), salt (I-601) to salt (I-604), salt (I-607) to salt (I-611), salt (I-614) to salt (I -630), salt (I-635) to salt (I-640), salt (I-641) to salt (I-644), salt (I-647) to salt (I-651), salt (I-654) to salt (I-670), salt (I-675) to salt (I-680), salt (I-681) to salt (I-684), salt (I-687) to salt (I-691), salt (I-694) to salt (I-710), salt (I-715) to salt (I-720), salt (I-721) to salt (I-724), salt (I-727) to salt (I-731), salt (I-734) to salt (I-750), salt (I-755) to salt (I-760), salt (I-761) to salt (I-764), salt (I-767) to salt (I-771), salt (I-774) to salt (I-790), salt (I-795) to salt (I-800), salt (I-801) ~ Salt (I-804), Salt (I-807) ~ Salt (I-811), Salt (I-814) ~ Salt (I-830), Salt (I-835) ~ Salt (I-840), Salt (I-841) ~ Salt (I-844), Salt (I-847) ~ Salt (I-851), Salt (I-854) ~ Salt (I-870), Salt (I-875) ~ Salt (I-880), Salt (I-881) ~ Salt (I-884), Salt (I-88 7) to salt (I-891), salt (I-894) to salt (I-910), salt (I-915) to salt (I-920), salt (I-921) to salt (I-924), salt (I-927) to salt (I-931), salt (I-934) to salt (I-950), salt (I-955) to salt (I-960), salt (I-961) to salt (I-964), salt (I-967) to salt (I-971), salt (I- 974) to salt (I-990), salt (I-995) to salt (I-1000), salt (I-1001) to salt (I-1004), salt (I-1007) to salt (I-1011), salt (I-1014) to salt (I-1030), salt (I-1035) to salt (I-1040), salt (I-1041) to salt (I-1044), salt (I-1047) to salt (I-1051), salt (I-105 4) to salt (I-1070), salt (I-1075) to salt (I-1080), salt (I-1081) to salt (I-1084), salt (I-1087) to salt (I-1091), salt (I-1094) to salt (I-1110), salt (I-1115) to salt (I-1120), salt (I-1121) to salt (I-1124), salt (I-1127) to salt (I-1131), salt (I-113 4) to salt (I-1150), salt (I-1155) to salt (I-1160), salt (I-1161) to salt (I-1164), salt (I-1167) to salt (I-1171), salt (I-1174) to salt (I-1190), salt (I-1195) to salt (I-1200), salt (I-1201) to salt (I-1204), salt (I-1207) to salt (I-1211), salt (I-121 4) to salt (I-1230), salt (I-1235) to salt (I-1240), salt (I-1241) to salt (I-1244), salt (I-1247) to salt (I-1251), salt (I-1254) to salt (I-1270), salt (I-1275) to salt (I-1280), salt (I-1281) to salt (I-1284), salt (I-1287) to salt (I-1291), salt (I-129 4) to salt (I-1310), salt (I-1315) to salt (I-1320), salt (I-1321) to salt (I-1324), salt (I-1327) to salt (I-1331), salt (I-1334) to salt (I-1350), salt (I-1355) to salt (I-1360), salt (I-1361) to salt (I-1364), salt (I-1367) to salt (I-1371), salt (I-137 4) to salt (I-1390), salt (I-1395) to salt (I-1400), salt (I-1401) to salt (I-1404), salt (I-1407) to salt (I-1411), salt (I-1414) to salt (I-1430), salt (I-1435) to salt (I-1440), salt (I-1441) to salt (I-1444), salt (I-1447) to salt (I-1451), salt (I-145 4) to salt (I-1470), salt (I-1475) to salt (I-1480), salt (I-1481) to salt (I-1484), salt (I-1487) to salt (I-1491), salt (I-1494) to salt (I-1510), salt (I-1515) to salt (I-1520), salt (I-1521) to salt (I-1524), salt (I-1527) to salt (I-1531), salt (I-153 4) ~ salt (I-1550), salt (I-1555) ~ salt (I-1560), salt (I-1561) ~ salt (I-1564), salt (I-1567) ~ salt (I-1571), salt (I-1574) ~ salt (I-1590), salt (I-1595) ~ salt (I-1600), salt (I-1601) ~ salt (I-1604), salt (I-1607) ~ salt (I-1611), salt (I-161 4) ~ salt (I-1630), salt (I-1635) ~ salt (I-1640), salt (I-1641) ~ salt (I-1644), salt (I-1647) ~ salt (I-1651), salt (I-1654) ~ salt (I-1670), salt (I-1675) ~ salt (I-1680), salt (I-1681) ~ salt (I-1684), salt (I-1687) ~ salt (I-1691), salt (I-169 4) ~ salt (I-1710), salt (I-1715) ~ salt (I-1720), salt (I-1721) ~ salt (I-1724), salt (I-1727) ~ salt (I-1731), salt (I-1734) ~ salt (I-1750), salt (I-1755) ~ salt (I-1760), salt (I-1761) ~ salt (I-1764), salt (I-1767) ~ salt (I-1771), salt (I-177 4) ~ salt (I-1790), salt (I-1795) ~ salt (I-1800), salt (I-1801) ~ salt (I-1804), salt (I-1807) ~ salt (I-1811), salt (I-1814) ~ salt (I-1830), salt (I-1835) ~ salt (I-1840), salt (I-1841) ~ salt (I-1844), salt (I-1847) ~ salt (I-1851), salt (I-185 4) ~ salt (I-1870), salt (I-1875) ~ salt (I-1880), salt (I-1881) ~ salt (I-1884), salt (I-1887) ~ salt (I-1891), salt (I-1894) ~ salt (I-1910), salt (I-1915) ~ salt (I-1920), salt (I-1921) ~ salt (I-1924), salt (I-1927) ~ salt (I-1931), salt (I-193 4) ~ Salt (I-1950), Salt (I-1955) ~ Salt (I-1960), Salt (I-1961) ~ Salt (I-1964), Salt (I-1967) ~ Salt (I-1971), Salt (I-1974) ~ Salt (I-1990), Salt (I-1995) ~ Salt (I-2000), Salt (I-2001) ~ Salt (I-2004), Salt (I-2007) ~ Salt (I-2011), Salt (I-201 4) ~ Salt (I-2030), Salt (I-2035) ~ Salt (I-2040), Salt (I-2041) ~ Salt (I-2044), Salt (I-2047) ~ Salt (I-2051), Salt (I-2054) ~ Salt (I-2070), Salt (I-2075) ~ Salt (I-2080), Salt (I-2081) ~ Salt (I-2084), Salt (I-2087) ~ Salt (I-2091), Salt (I-209 4) to salt (I-2110), salt (I-2115) to salt (I-2120), salt (I-2121) to salt (I-2124), salt (I-2127) to salt (I-2131), salt (I-2134) to salt (I-2150), salt (I-2155) to salt (I-2160), salt (I-2161) to salt (I-2164), salt (I-2167) to salt (I-2171), salt (I-217 4) to salt (I-2190), salt (I-2195) to salt (I-2200), salt (I-2201) to salt (I-2204), salt (I-2207) to salt (I-2211), salt (I-2214) to salt (I-2230), salt (I-2235) to salt (I-2240), salt (I-2241) to salt (I-2244), salt (I-2247) to salt (I-2251), salt (I-225 4) ~ salt (I-2270), salt (I-2275) ~ salt (I-2280), salt (I-2281) ~ salt (I-2284), salt (I-2287) ~ salt (I-2291), salt (I-2294) ~ salt (I-2310), salt (I-2315) ~ salt (I-2320), salt (I-2321) ~ salt (I-2324), salt (I-2327) ~ salt (I-2331), salt (I-233 4) ~ Salt (I-2350), Salt (I-2355) ~ Salt (I-2360), Salt (I-2361) ~ Salt (I-2364), Salt (I-2367) ~ Salt (I-2371), Salt (I-2374) ~ Salt (I-2390), Salt (I-2395) ~ Salt (I-2400), Salt (I-2401) ~ Salt (I-2404), Salt (I-2407) ~ Salt (I-2411), Salt (I-241 4) ~ salt (I-2430), salt (I-2435) ~ salt (I-2440), salt (I-2441) ~ salt (I-2444), salt (I-2447) ~ salt (I-2451), salt (I-2454) ~ salt (I-2470), salt (I-2475) ~ salt (I-2480), salt (I-2481) ~ salt (I-2484), salt (I-2487) ~ salt (I-2491), salt (I-249 4) ~ salt (I-2510), salt (I-2515) ~ salt (I-2520), salt (I-2521) ~ salt (I-2524), salt (I-2527) ~ salt (I-2531), salt (I-2534) ~ salt (I-2550), salt (I-2555) ~ salt (I-2560), salt (I-2561) ~ salt (I-2564), salt (I-2567) ~ salt (I-2571), salt (I-257
4) ~ salt (I-2590), salt (I-2595) ~ salt (I-2600), salt (I-2601) ~ salt (I-2604), salt (I-2607) ~ salt (I-2611), salt (I-2614) ~ salt (I-2630), salt (I-2635) ~ salt (I-2640), salt (I-2641) ~ salt (I-2644), salt (I-2647) ~ salt (I-2651), salt (I-265 4) ~ salt (I-2670), salt (I-2675) ~ salt (I-2680), salt (I-2681) ~ salt (I-2684), salt (I-2687) ~ salt (I-2691), salt (I-2694) ~ salt (I-2710), salt (I-2715) ~ salt (I-2720), salt (I-2721) ~ salt (I-2724), salt (I-2727) ~ salt (I-2731), salt (I-273 4) ~ salt (I-2750), salt (I-2755) ~ salt (I-2760), salt (I-2761) ~ salt (I-2764), salt (I-2767) ~ salt (I-2771), salt (I-2774) ~ salt (I-2790), salt (I-2795) ~ salt (I-2800), salt (I-2801) ~ salt (I-2804), salt (I-2807) ~ salt (I-2811), salt (I-281 4) ~ salt (I-2830), salt (I-2835) ~ salt (I-2840), salt (I-2841) ~ salt (I-2844), salt (I-2847) ~ salt (I-2851), salt (I-2881) ~ salt (I-2884), salt (I-2887) ~ salt (I-2891), salt (I-2894) ~ salt (I-2910), salt (I-2915) ~ salt (I-2920), salt (I-292 1) ~ Salt (I-2924), Salt (I-2927) ~ Salt (I-2931), Salt (I-2934) ~ Salt (I-2950), Salt (I-2955) ~ Salt (I-2960), Salt (I-2961) ~ Salt (I-2964), Salt (I-2967) ~ Salt (I-2971), Salt (I-2974) ~ Salt (I-2990), Salt (I-2995) ~ Salt (I-3000), Salt (I-300) 1) to salt (I-3004), salt (I-3007) to salt (I-3011), salt (I-3014) to salt (I-3030), salt (I-3035) to salt (I-3040), salt (I-3041) to salt (I-3044), salt (I-3047) to salt (I-3051), salt (I-3054) to salt (I-3070), salt (I-3075) to salt (I-3080), salt (I-308 1) to salt (I-3084), salt (I-3087) to salt (I-3091), salt (I-3094) to salt (I-3110), salt (I-3115) to salt (I-3120), salt (I-3121) to salt (I-3124), salt (I-3127) to salt (I-3131), salt (I-3134) to salt (I-3150), salt (I-3155) to salt (I-3160), salt (I-316 1) to salt (I-3164), salt (I-3167) to salt (I-3171), salt (I-3174) to salt (I-3190), salt (I-3195) to salt (I-3200), salt (I-3201) to salt (I-3204), salt (I-3207) to salt (I-3211), salt (I-3214) to salt (I-3230), salt (I-3235) to salt (I-3240), salt (I-324 1) to salt (I-3244), salt (I-3247) to salt (I-3251), salt (I-3254) to salt (I-3270), salt (I-3275) to salt (I-3280), salt (I-3281) to salt (I-3284), salt (I-3287) to salt (I-3291), salt (I-3294) to salt (I-3310), salt (I-3315) to salt (I-3320), salt (I-332 1) to salt (I-3324), salt (I-3327) to salt (I-3331), salt (I-3334) to salt (I-3350), salt (I-3355) to salt (I-3360), salt (I-3361) to salt (I-3364), salt (I-3367) to salt (I-3371), salt (I-3374) to salt (I-3390), salt (I-3395) to salt (I-3400), salt (I-340 1) to salt (I-3404), salt (I-3407) to salt (I-3411), salt (I-3414) to salt (I-3430), salt (I-3435) to salt (I-3440), salt (I-3441) to salt (I-3444), salt (I-3447) to salt (I-3451), salt (I-3454) to salt (I-3470), salt (I-3475) to salt (I-3480), salt (I-348 1) to salt (I-3484), salt (I-3487) to salt (I-3491), salt (I-3494) to salt (I-3510), salt (I-3515) to salt (I-3520), salt (I-3521) to salt (I-3524), salt (I-3527) to salt (I-3531), salt (I-3534) to salt (I-3550), salt (I-3555) to salt (I-3560), salt (I-356 1) to salt (I-3564), salt (I-3567) to salt (I-3571), salt (I-3574) to salt (I-3590), salt (I-3595) to salt (I-3600), salt (I-3601) to salt (I-3604), salt (I-3607) to salt (I-3611), salt (I-3614) to salt (I-3630), salt (I-3635) to salt (I-3640), salt (I-364 1) to salt (I-3644), salt (I-3647) to salt (I-3651), salt (I-3654) to salt (I-3670), salt (I-3675) to salt (I-3680), salt (I-3681) to salt (I-3684), salt (I-3687) to salt (I-3691), salt (I-3694) to salt (I-3710), salt (I-3715) to salt (I-3720), salt (I-372 1) ~ salt (I-3724), salt (I-3727) ~ salt (I-3731), salt (I-3734) ~ salt (I-3750), salt (I-3755) ~ salt (I-3760), salt (I-3761) ~ salt (I-3764), salt (I-3767) ~ salt (I-3771), salt (I-3774) ~ salt (I-3790), salt (I-3795) ~ salt (I-3800), salt (I-380 1) to salt (I-3804), salt (I-3807) to salt (I-3811), salt (I-3814) to salt (I-3830), salt (I-3835) to salt (I-3840), salt (I-3841) to salt (I-3844), salt (I-3847) to salt (I-3851), salt (I-3881) to salt (I-3884), salt (I-3887) to salt (I-3891), salt (I-389 4) to salt (I-3910), salt (I-3915) to salt (I-3920), salt (I-3921) to salt (I-3924), salt (I-3927) to salt (I-3931), salt (I-3934) to salt (I-3950), salt (I-3955) to salt (I-3960), salt (I-3961) to salt (I-3964), salt (I-3967) to salt (I-3971), salt (I-397 4) to salt (I-3990), salt (I-3995) to salt (I-4000), salt (I-4001) to salt (I-4004), salt (I-4007) to salt (I-4011), salt (I-4014) to salt (I-4030), salt (I-4035) to salt (I-4040), salt (I-4041) to salt (I-4044), salt (I-4047) to salt (I-4051), salt (I-405 4) to salt (I-4070), salt (I-4075) to salt (I-4080), salt (I-4081) to salt (I-4084), salt (I-4087) to salt (I-4091), salt (I-4094) to salt (I-4110), salt (I-4115) to salt (I-4120), salt (I-4121) to salt (I-4124), salt (I-4127) to salt (I-4131), salt (I-413 4) to salt (I-4150), salt (I-4155) to salt (I-4160), salt (I-4161) to salt (I-4164), salt (I-4167) to salt (I-4171), salt (I-4174) to salt (I-4190), salt (I-4195) to salt (I-4200), salt (I-4201) to salt (I-4204), salt (I-4207) to salt (I-4211), salt (I-421 4) to salt (I-4230), salt (I-4235) to salt (I-4240), salt (I-4241) to salt (I-4244), salt (I-4247) to salt (I-4251), salt (I-4254) to salt (I-4270), salt (I-4275) to salt (I-4280), salt (I-4281) to salt (I-4284), salt (I-4287) to salt (I-4291), salt (I-429 4) to salt (I-4310), salt (I-4315) to salt (I-4320), salt (I-4321) to salt (I-4324), salt (I-4327) to salt (I-4331), salt (I-4334) to salt (I-4350), salt (I-4355) to salt (I-4360), salt (I-4361) to salt (I-4364), salt (I-4367) to salt (I-4371), salt (I-437 4) to salt (I-4390), salt (I-4395) to salt (I-4400), salt (I-4401) to salt (I-4404), salt (I-4407) to salt (I-4411), salt (I-4414) to salt (I-4430), salt (I-4435) to salt (I-4440), salt (I-4441) to salt (I-4444), salt (I-4447) to salt (I-4451), salt (I-445 4) ~ salt (I-4470), salt (I-4475) ~ salt (I-4480), salt (I-4481) ~ salt (I-4484), salt (I-4487) ~ salt (I-4491), salt (I-4494) ~ salt (I-4510), salt (I-4515) ~ salt (I-4520), salt (I-4521) ~ salt (I-4524), salt (I-4527) ~ salt (I-4531), salt (I-453 4) ~ salt (I-4550), salt (I-4555) ~ salt (I-4560), salt (I-4561) ~ salt (I-4564), salt (I-4567) ~ salt (I-4571), salt (I-4574) ~ salt (I-4590), salt (I-4595) ~ salt (I-4600), salt (I-4601) ~ salt (I-4604), salt (I-4607) ~ salt (I-4611), salt (I-461 4) ~ salt (I-4630), salt (I-4635) ~ salt (I-4640), salt (I-4641) ~ salt (I-4644), salt (I-4647) ~ salt (I-4651), salt (I-4654) ~ salt (I-4670), salt (I-4675) ~ salt (I-4680), salt (I-4681) ~ salt (I-4684), salt (I-4687) ~ salt (I-4691), salt (I-469 4) ~ salt (I-4710), salt (I-4715) ~ salt (I-4720), salt (I-4721) ~ salt (I-4724), salt (I-4727) ~ salt (I-4731), salt (I-4734) ~ salt (I-4750), salt (I-4755) ~ salt (I-4760), salt (I-4761) ~ salt (I-4764), salt (I-4767) ~ salt (I-4771), salt (I-477 4) ~ Salt (I-4790), Salt (I-4795) ~ Salt (I-4800), Salt (I-4801) ~ Salt (I-4804), Salt (I-4807) ~ Salt (I-4811), Salt (I-4814) ~ Salt (I-4830), Salt (I-4835) ~ Salt (I-4840), Salt (I-4841) ~ Salt (I-4844), Salt (I-4847) ~ Salt (I-4851), Salt (I-488 1) to salt (I-4884), salt (I-4887) to salt (I-4891), salt (I-4894) to salt (I-4910), salt (I-4915) to salt (I-4920), salt (I-4921) to salt (I-4924), salt (I-4927) to salt (I-4931), salt (I-4934) to salt (I-4950), salt (I-4955) to salt (I-4960), salt (I-496 1) to salt (I-4964), salt (I-4967) to salt (I-4971), salt (I-4974) to salt (I-4990), salt (I-4995) to salt (I-5000), salt (I-5001) to salt (I-5004), salt (I-5007) to salt (I-5011), salt (I-5014) to salt (I-5030), salt (I-5035) to salt (I-5040), salt (I-504 1) to salt (I-5044), salt (I-5047) to salt (I-5051), salt (I-5054) to salt (I-5070), salt (I-5075) to salt (I-5080), salt (I-5081) to salt (I-5084), salt (I-5087) to salt (I-5091), salt (I-5094) to salt (I-5110), salt (I-5115) to salt (I-5120), salt (I-512 1) to salt (I-5124), salt (I-5127) to salt (I-5131), salt (I-5134) to salt (I-5150), salt (I-5155) to salt (I-5160), salt (I-5161) to salt (I-5164), salt (I-5167) to salt (I-5171), salt (I-5174) to salt (I-5190), salt (I-5195) to salt (I-5200), salt (I-5201
) to salt (I-5204), salt (I-5207) to salt (I-5211), salt (I-5214) to salt (I-5230), salt (I-5235) to salt (I-5240), salt (I-5241) to salt (I-5244), salt (I-5247) to salt (I-5251), salt (I-5254) to salt (I-5270), salt (I-5275) to salt (I-5280), salt (I-5281) ) to salt (I-5284), salt (I-5287) to salt (I-5291), salt (I-5294) to salt (I-5310), salt (I-5315) to salt (I-5320), salt (I-5321) to salt (I-5324), salt (I-5327) to salt (I-5331), salt (I-5334) to salt (I-5350), salt (I-5355) to salt (I-5360), salt (I-5361) ) to salt (I-5364), salt (I-5367) to salt (I-5371), salt (I-5374) to salt (I-5390), salt (I-5395) to salt (I-5400), salt (I-5401) to salt (I-5404), salt (I-5407) to salt (I-5411), salt (I-5414) to salt (I-5430), salt (I-5435) to salt (I-5440), salt (I-5441) ) to salt (I-5444), salt (I-5447) to salt (I-5451), salt (I-5454) to salt (I-5470), salt (I-5475) to salt (I-5480), salt (I-5481) to salt (I-5484), salt (I-5487) to salt (I-5491), salt (I-5494) to salt (I-5510), salt (I-5515) to salt (I-5520), salt (I-5521 ) to salt (I-5524), salt (I-5527) to salt (I-5531), salt (I-5534) to salt (I-5550), salt (I-5555) to salt (I-5560), salt (I-5561) to salt (I-5564), salt (I-5567) to salt (I-5571), salt (I-5574) to salt (I-5590), salt (I-5595) to salt (I-5600), salt (I-5601 ) to salt (I-5604), salt (I-5607) to salt (I-5611), salt (I-5614) to salt (I-5630), salt (I-5635) to salt (I-5640), salt (I-5641) to salt (I-5644), salt (I-5647) to salt (I-5651), salt (I-5654) to salt (I-5670), salt (I-5675) to salt (I-5680), salt (I-5681) ) to salt (I-5684), salt (I-5687) to salt (I-5691), salt (I-5694) to salt (I-5710), salt (I-5715) to salt (I-5720), salt (I-5721) to salt (I-5724), salt (I-5727) to salt (I-5731), salt (I-5734) to salt (I-5750), salt (I-5755) to salt (I-5760), salt (I-5761 ) ~ salt (I-5764), salt (I-5767) ~ salt (I-5771), salt (I-5774) ~ salt (I-5790), salt (I-5795) ~ salt (I-5800), salt (I-5801) ~ salt (I-5804), salt (I-5807) ~ salt (I-5811), salt (I-5814) ~ salt (I-5830), salt (I-5835) ~ salt (I-5840), salt (I-5841) ) to salt (I-5844), salt (I-5847) to salt (I-5851), salt (I-5881) to salt (I-5884), salt (I-5887) to salt (I-5891), salt (I-5894) to salt (I-5910), salt (I-5915) to salt (I-5920), salt (I-5921) to salt (I-5924), salt (I-5927) to salt (I-5931), salt (I-5934) ) ~ salt (I-5950), salt (I-5955) ~ salt (I-5960), salt (I-5961) ~ salt (I-5964), salt (I-5967) ~ salt (I-5971), salt (I-5974) ~ salt (I-5990), salt (I-5995) ~ salt (I-6000), salt (I-6001) ~ salt (I-6004), salt (I-6007) ~ salt (I-6011), salt (I-6014) ) to salt (I-6030), salt (I-6035) to salt (I-6040), salt (I-6041) to salt (I-6044), salt (I-6047) to salt (I-6051), salt (I-6054) to salt (I-6070), salt (I-6075) to salt (I-6080), salt (I-6081) to salt (I-6084), salt (I-6087) to salt (I-6091), salt (I-6094 ) to salt (I-6110), salt (I-6115) to salt (I-6120), salt (I-6121) to salt (I-6124), salt (I-6127) to salt (I-6131), salt (I-6134) to salt (I-6150), salt (I-6155) to salt (I-6160), salt (I-6161) to salt (I-6164), salt (I-6167) to salt (I-6171), salt (I-6174 ) to salt (I-6190), salt (I-6195) to salt (I-6200), salt (I-6201) to salt (I-6204), salt (I-6207) to salt (I-6211), salt (I-6214) to salt (I-6230), salt (I-6235) to salt (I-6240), salt (I-6241) to salt (I-6244), salt (I-6247) to salt (I-6251), salt (I-6254 ) to salt (I-6270), salt (I-6275) to salt (I-6280), salt (I-6281) to salt (I-6284), salt (I-6287) to salt (I-6291), salt (I-6294) to salt (I-6310), salt (I-6315) to salt (I-6320), salt (I-6321) to salt (I-6324), salt (I-6327) to salt (I-6331), salt (I-6334 ) ~ salt (I-6350), salt (I-6355) ~ salt (I-6360), salt (I-6361) ~ salt (I-6364), salt (I-6367) ~ salt (I-6371), salt (I-6374) ~ salt (I-6390), salt (I-6395) ~ salt (I-6400), salt (I-6401) ~ salt (I-6404), salt (I-6407) ~ salt (I-6411), salt (I-6414 ) to salt (I-6430), salt (I-6435) to salt (I-6440), salt (I-6441) to salt (I-6444), salt (I-6447) to salt (I-6451), salt (I-6454) to salt (I-6470), salt (I-6475) to salt (I-6480), salt (I-6481) to salt (I-6484), salt (I-6487) to salt (I-6491), salt (I-6494 ) to salt (I-6510), salt (I-6515) to salt (I-6520), salt (I-6521) to salt (I-6524), salt (I-6527) to salt (I-6531), salt (I-6534) to salt (I-6550), salt (I-6555) to salt (I-6560), salt (I-6561) to salt (I-6564), salt (I-6567) to salt (I-6571), salt (I-6574 ) to salt (I-6590), salt (I-6595) to salt (I-6600), salt (I-6601) to salt (I-6604), salt (I-6607) to salt (I-6611), salt (I-6614) to salt (I-6630), salt (I-6635) to salt (I-6640), salt (I-6641) to salt (I-6644), salt (I-6647) to salt (I-6651), salt (I-6654 ) ~ salt (I-6670), salt (I-6675) ~ salt (I-6680), salt (I-6681) ~ salt (I-6684), salt (I-6687) ~ salt (I-6691), salt (I-6694) ~ salt (I-6710), salt (I-6715) ~ salt (I-6720), salt (I-6721) ~ salt (I-6724), salt (I-6727) ~ salt (I-6731), salt (I-6734) ) ~ salt (I-6750), salt (I-6755) ~ salt (I-6760), salt (I-6761) ~ salt (I-6764), salt (I-6767) ~ salt (I-6771), salt (I-6774) ~ salt (I-6790), salt (I-6795) ~ salt (I-6800), salt (I-6801) ~ salt (I-6804), salt (I-6807) ~ salt (I-6811), salt (I-6814) ) to salt (I-6830), salt (I-6835) to salt (I-6840), salt (I-6841) to salt (I-6844), salt (I-6847) to salt (I-6851), salt (I-6881) to salt (I-6884), salt (I-6887) to salt (I-6891), salt (I-6894) to salt (I-6910), salt (I-6915) to salt (I-6920), salt (I-6921 ) ~ salt (I-6924), salt (I-6927) ~ salt (I-6931), salt (I-6934) ~ salt (I-6950), salt (I-6955) ~ salt (I-6960), salt (I-6961) ~ salt (I-6964), salt (I-6967) ~ salt (I-6971), salt (I-6974) ~ salt (I-6990), salt (I-6995) ~ salt (I-7000), salt (I-7001 ) to salt (I-7004), salt (I-7007) to salt (I-7011), salt (I-7014) to salt (I-7030), salt (I-7035) to salt (I-7040), salt (I-7041) to salt (I-7044), salt (I-7047) to salt (I-7051), salt (I-7054) to salt (I-7070), salt (I-7075) to salt (I-7080), salt (I-7081) ) to salt (I-7084), salt (I-7087) to salt (I-7091), salt (I-7094) to salt (I-7110), salt (I-7115) to salt (I-7120), salt (I-7121) to salt (I-7124), salt (I-7127) to salt (I-7131), salt (I-7134) to salt (I-7150), salt (I-7155) to salt (I-7160), salt (I-7161 ) ~ salt (I-7164), salt (I-7167) ~ salt (I-7171), salt (I-7174) ~ salt (I-7190), salt (I-7195) ~ salt (I-7200), salt (I-7201) ~ salt (I-7204), salt (I-7207) ~ salt (I-7211), salt (I-7214) ~ salt (I-7230), salt (I-7235) ~ salt (I-7240), salt (I-7241) ) ~ salt (I-7244), salt (I-7247) ~ salt (I-7251), salt (I-7254) ~ salt (I-7270), salt (I-7275) ~ salt (I-7280), salt (I-7281) ~ salt (I-7284), salt (I-7287) ~ salt (I-7291), salt (I-7294) ~ salt (I-7310), salt (I-7315) ~ salt (I-7320), salt (I-7321 ) ~ salt (I-7324), salt (I-7327) ~ salt (I-7331), salt (I-7334) ~ salt (I-7350), salt (I-7355) ~ salt (I-7360), salt (I-7361) ~ salt (I-7364), salt (I-7367) ~ salt (I-7371), salt (I-7374) ~ salt (I-7390), salt (I-7395) ~ salt (I-7400), salt (I-7401 ) to salt (I-7404), salt (I-7407) to salt (I-7411), salt (I-7414) to salt (I-7430), salt (I-7435) to salt (I-7440), salt (I-7441) to salt (I-7444), salt (I-7447) to salt (I-7451), salt (I-7454) to salt (I-7470), salt (I-7475) to salt (I-7480), salt (I-7481) ) ~ salt (I-7484), salt (I-7487) ~ salt (I-7491), salt (I-7494) ~ salt (I-7510), salt (I-7515) ~ salt (I-7520), salt (I-7521) ~ salt (I-7524), salt (I-7527) ~ salt (I-7531), salt (I-7534) ~ salt (I-7550), salt (I-7555) ~ salt (I-7560), salt (I-7561) ) ~ salt (I-7564), salt (I-7567) ~ salt (I-7571), salt (I-7574) ~ salt (I-7590), salt (I-7595) ~ salt (I-7600), salt (I-7601) ~ salt (I-7604), salt (I-7607) ~ salt (I-7611), salt (I-7614) ~ salt (I-7630), salt (I-7635) ~ salt (I-7640), salt (I-7641) ) ~ salt (I-7644), salt (I-7647) ~ salt (I-7651), salt (I-7654) ~ salt (I-7670), salt (I-7675) ~ salt (I-7680), salt (I-7681) ~ salt (I-7684), salt (I-7687) ~ salt (I-7691), salt (I-7694) ~ salt (I-7710), salt (I-7715) ~ salt (I-7720), salt (I-7721 ) ~ salt (I-7724), salt (I-7727) ~ salt (I-7731), salt (I-7734) ~ salt (I-7750), salt (I-7755) ~ salt (I-7760), salt (I-7761) ~ salt (I-7764), salt (I-7767) ~ salt (I-7771), salt (I-7774) ~ salt (I-7790), salt (I-7795) ~ salt (I-7800), salt (I-7801)
~ Salt (I-7804), Salt (I-7807) ~ Salt (I-7811), Salt (I-7814) ~ Salt (I-7830), Salt (I-7835) ~ Salt (I-7840), Salt (I-7841) ~ Salt (I-7844), Salt (I-7847) ~ Salt (I-7851), Salt (I-7881) ~ Salt (I-7884), Salt (I-7887) ~ Salt (I-7891), Salt (I-7894) ~ Salt (I-7910), Salt (I-7915) ~ Salt (I-7920), Salt (I-7921) ~ Salt (I-7924), Salt (I-7927) ~ Salt (I-7931), Salt (I-7934) ~ Salt (I-7950), Salt (I-7955) ~ Salt (I-7960), Salt (I-7961) ~ Salt (I-7964), Salt (I-7967) ~ Salt (I-7971), Salt (I-7974) ~ Salt (I-7990), Salt (I-7995) ~ Salt (I-8000), Salt (I-8001) ~ Salt (I-8004), Salt (I-8007) ~ Salt (I-8011), Salt (I-8014) ~ Salt (I-8030), Salt (I-8035) ~ Salt (I-8040), Salt (I-8041) ~ Salt (I-8044), Salt (I-8047) ~ Salt (I-8051), Salt (I-8054) ~ Salt (I-8070), Salt (I-8075) ~ Salt (I-8080), Salt (I-8081) ~ Salt (I-8084), Salt (I-8087) ~ Salt (I-8091), Salt (I-8094) ~ Salt (I-8110), Salt (I-8115) ~ Salt (I-8120), Salt (I-8121) ~ Salt (I-8124), Salt (I-8127) ~ Salt (I-8131), Salt (I-8134) ~ Salt (I-8150), Salt (I-8155) ~ Salt (I-8160), Salt (I-8161) ~ Salt (I-8164), Salt (I-8167) ~ Salt (I-8171), Salt (I-8174) ~ Salt (I-8190), Salt (I-8195) ~ Salt (I-8200), Salt (I-8201) ~ Salt (I-8204), Salt (I-8207) ~ Salt (I-8211), Salt (I-8214) ~ Salt (I-8230), Salt (I-8235) ~ Salt (I-8240), Salt (I-8241) ~ Salt (I-8244), Salt (I-8247) ~ Salt (I-8251), Salt (I-8254) ~ Salt (I-8270), Salt (I-8275) ~ Salt (I-8280), Salt (I-8281) ~ Salt (I-8284), Salt (I-8287) ~ Salt (I-8291), Salt (I-8294) ~ Salt (I-8310), Salt (I-8315) ~ Salt (I-8320), Salt (I-8321) ~ Salt (I-8324), Salt (I-8327) ~ Salt (I-8331), Salt (I-8334) ~ Salt (I-8350), Salt (I-8355) ~ Salt (I-8360), Salt (I-8361) ~ Salt (I-8364), Salt (I-8367) ~ Salt (I-8371), Salt (I-8374) ~ Salt (I-8390), Salt (I-8395) ~ Salt (I-8400), Salt (I-8401) ~ Salt (I-8404), Salt (I-8407) ~ Salt (I-8411), Salt (I-8414) ~ Salt (I-8430), Salt (I-8435) ~ Salt (I-8440), Salt (I-8441) ~ Salt (I-8444), Salt (I-8447) ~ Salt (I-8451), Salt (I-8454) ~ Salt (I-8470), Salt (I-8475) ~ Salt (I-8480), Salt (I-8481) ~ Salt (I-8484), Salt (I-8487) ~ Salt (I-8491), Salt (I-8494) ~ Salt (I-8510), Salt (I-8515) ~ Salt (I-8520), Salt (I-8521) ~ Salt (I-8524), Salt (I-8527) ~ Salt (I-8531), Salt (I-8534) ~ Salt (I-8550), Salt (I-8555) ~ Salt (I-8560), Salt (I-8561) ~ Salt (I-8564), Salt (I-8567) ~ Salt (I-8571), Salt (I-8574) ~ Salt (I-8590), Salt (I-8595) ~ Salt (I-8600), Salt (I-8601) ~ Salt (I-8604), Salt (I-8607) ~ Salt (I-8611), Salt (I-8614) ~ Salt (I-8630), Salt (I-8635) ~ Salt (I-8640), Salt (I-8641) ~ Salt (I-8644), Salt (I-8647) ~ Salt (I-8651), Salt (I-8654) ~ Salt (I-8670), Salt (I-8675) ~ Salt (I-8680), Salt (I-8681) ~ Salt (I-8684), Salt (I-8687) ~ Salt (I-8691), Salt (I-8694) ~ Salt (I-8710), Salt (I-8715) ~ Salt (I-8720), Salt (I-8721) ~ Salt (I-8724), Salt (I-8727) ~ Salt (I-8731), Salt (I-8734) ~ Salt (I-8750), Salt (I-8755) ~ Salt (I-8760), Salt (I-8761) ~ Salt (I-8764), Salt (I-8767) ~ Salt (I-8771), Salt (I-8774) ~ Salt (I-8790), Salt (I-8795) ~ Salt (I-8800), Salt (I-8801) ~ Salt (I-8804), Salt (I-8807) ~ Salt (I-8811), Salt (I-8814) ~ Salt (I-8830), Salt (I-8835) ~ Salt (I-8840), Salt (I-8841) ~ Salt (I-8844), Salt (I-8847) ~ Salt (I-8851), Salt (I-8881) ~ Salt (I-8884), Salt (I-8887) ~ Salt (I-8891), Salt (I-8894) ~ Salt (I-8910), Salt (I-8915) ~ Salt (I-8920), Salt (I-8921) ~ Salt (I-8924), Salt (I-8927) ~ Salt (I-8931), Salt (I-8934) ~ Salt (I-8950), Salt (I-8955) ~ Salt (I-8960), Salt (I-8961) ~ Salt (I-8964), Salt (I-8967) ~ Salt (I-8971), Salt (I-8974) ~ Salt (I-8990), Salt (I-8995) ~ Salt (I-9000), Salt (I-9001) ~ Salt (I-9004), Salt (I-9007) ~ Salt (I-9011), Salt (I-9014) ~ Salt (I-9030), Salt (I-9035) ~ Salt (I-9040), Salt (I-9041) ~ Salt (I-9044), Salt (I-9047) ~ Salt (I-9051), Salt (I-9054) ~ Salt (I-9070), Salt (I-9075) ~ Salt (I-9080), Salt (I-9081) ~ Salt (I-9084), Salt (I-9087) ~ Salt (I-9091), Salt (I-9094) ~ Salt (I-9110), Salt (I-9115) ~ Salt (I-9120), Salt (I-9121) ~ Salt (I-9124), Salt (I-9127) ~ Salt (I-9131), Salt (I-9134) ~ Salt (I-9150), Salt (I-9155) ~ Salt (I-9160), Salt (I-9161) ~ Salt (I-9164), Salt (I-9167) ~ Salt (I-9171), Salt (I-9174) ~ Salt (I-9190), Salt (I-9195) ~ Salt (I-9200), Salt (I-9201) ~ Salt (I-9204), Salt (I-9207) ~ Salt (I-9211), Salt (I-9214) ~ Salt (I-9230), Salt (I-9235) ~ Salt (I-9240), Salt (I-9241) ~ Salt (I-9244), Salt (I-9247) ~ Salt (I-9251), Salt (I-9254) ~ Salt (I-9270), Salt (I-9275) ~ Salt (I-9280), Salt (I-9281) ~ Salt (I-9284), Salt (I-9287) ~ Salt (I-9291), Salt (I-9294) ~ Salt (I-9310), Salt (I-9315) ~ Salt (I-9320), Salt (I-9321) ~ Salt (I-9324), Salt (I-9327) ~ Salt (I-9331), Salt (I-9334) ~ Salt (I-9350), Salt (I-9355) ~ Salt (I-9360), Salt (I-9361) ~ Salt (I-9364), Salt (I-9367) ~ Salt (I-9371), Salt (I-9374) ~ Salt (I-9390), Salt (I-9395) ~ Salt (I-9400), Salt (I-9401) ~ Salt (I-9404), Salt (I-9407) ~ Salt (I-9411), Salt (I-9414) ~ Salt (I-9430), Salt (I-9435) ~ Salt (I-9440), Salt (I-9441) ~ Salt (I-9444), Salt (I-9447) ~ Salt (I-9451), Salt (I-9454) ~ Salt (I-9470), Salt (I-9475) ~ Salt (I-9480), Salt (I-9481) ~ Salt (I-9484), Salt (I-9487) ~ Salt (I-9491), Salt (I-9494) ~ Salt (I-9510), Salt (I-9515) ~ Salt (I-9520), Salt (I-9521) ~ Salt (I-9524), Salt (I-9527) ~ Salt (I-9531), Salt (I-9534) ~ Salt (I-9550), Salt (I-9555) ~ Salt (I-9560), Salt (I-9561) ~ Salt (I-9564), Salt (I-9567) ~ Salt (I-9571), Salt (I-9574) ~ Salt (I-9590), Salt (I-9595) ~ Salt (I-9600), Salt (I-9601) ~ Salt (I-9604), Salt (I-9607) ~ Salt (I-9611), Salt (I-9614) ~ Salt (I-9630), Salt (I-9635) ~ Salt (I-9640), Salt (I-9641) ~ Salt (I-9644), Salt (I-9647) ~ Salt (I-9651), Salt (I-9654) ~ Salt (I-9670), Salt (I-9675) ~ Salt (I-9680), Salt (I-9681) ~ Salt (I-9684), Salt (I-9687) ~ Salt (I-9691), Salt (I-9694) ~ Salt (I-9710), Salt (I-9715) ~ Salt (I-9720), Salt (I-9721) ~ Salt (I-9724), Salt (I-9727) ~ Salt (I-9731), Salt (I-9734) ~ Salt (I-9750), Salt (I-9755) ~ Salt (I-9760), Salt (I-9761) ~ Salt (I-9764), Salt (I-9767) ~ Salt (I-9771), Salt (I-9774) ~ Salt (I-9790), Salt (I-9795) ~ Salt (I-9800), Salt (I-9801) ~ Salt (I-9804), Salt (I-9807) ~ Salt (I-9811), Salt (I-9814) ~ Salt (I-9830), Salt (I-9835) ~ Salt (I-9840), Salt (I-9841) ~ Salt (I-9844), Salt (I-9847) ~ Salt (I-9851), Salt (I-9881) ~ Salt (I-9884), Salt (I-9887) ~ Salt (I-9891), Salt (I-9894) ~ Salt (I-9910), Salt (I-9915) ~ Salt (I-9920), Salt (I-9921) ~ Salt (I-9924), Salt (I-9927) ~ Salt (I-9931), Salt (I-9934) ~ Salt (I-9950), Salt (I-9955) ~ Salt (I-9960), Salt (I-9961) ~ Salt (I-9964), Salt (I-9967) ~ Salt (I-9971), Salt (I-9974) ~ Salt (I-9990), Salt (I-9995) ~ Salt (I-10000), Salt (I-10001) ~ Salt (I-10004), Salt (I-10007) ~ Salt (I-10011), Salt (I-10014) ~ Salt (I-10030), Salt ( Preferably, the salts are (I-10035) to (I-10040), (I-10041) to (I-10044), (I-10047) to (I-10051), (I-10054) to (I-10070), (I-10075) to (I-10836), and (I-13861) to (I-18900).

<Method for producing salt (I)>
The salt (I) can be produced by reacting a salt represented by the formula (Ia) with a salt represented by the formula (Ib) in a solvent.

[In the formula, the symbols ^Ar1 , ^Ar2 , ^Ar3 , ^R1 , ^R2 , R3, ^R4 , ^R5 , ^R6 , ^R7 , ^R8 , ^R9 , X, m1, m2, m3, m4, ^m5 , m6, m7, m8, m9, m10, ^A1 , ^A2 , ^A3 , and ^AI- each have the same meaning as in formula (I) above.

R ^A , R ^B and R ^C each independently represent a hydrocarbon group having 1 to 12 carbon atoms, or R ^A , R ^B and R ^C may combine with each other to form an aromatic ring. R ^D represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.]
Examples of the solvent include chloroform, monochlorobenzene, acetonitrile, and water.

The reaction temperature is usually 15° C. to 80° C., and the reaction time is usually 0.5 to 24 hours.
Examples of the salt represented by formula (I-b) include salts represented by the following formulas: These salts can be easily produced by the same method as that described in JP-A-2011-116747 and JP-A-2016-047815, or by known production methods.

The salt (I-a) in which R ¹ , R ² and R ³ are *-OL ¹⁰ -CO-O-R ¹⁰ (salt represented by formula (I-a1) below) can be produced by reacting a salt represented by formula (I-c) with a compound represented by formula (I-d) in a solvent in the presence of a base catalyst.

[In the formula, all symbols have the same meaning as defined above. In the formula (I), when R ⁴ , R ⁵ and R ⁶ contain a group having a cyclic carbonate structure, R ⁴ , R ⁵ and R ⁶ in the formula (I-c) may be replaced with —OH.]
Examples of the base catalyst include potassium carbonate, potassium iodide, pyridine, and triethylamine.

Examples of the solvent include chloroform, monochlorobenzene, dimethylformamide, acetonitrile, ethyl acetate, and water.
The reaction temperature is usually 15° C. to 80° C., and the reaction time is usually 0.5 to 24 hours.

Compounds represented by formula (I-d) include, for example, the compounds represented below, which are readily available on the market and can also be easily produced by known methods.

The salt represented by formula (I-c) can be produced by reacting the salt represented by formula (I-e), the compound represented by formula (I-f1), the compound represented by formula (I-f2), and the compound represented by formula (I-f3) in a solvent in the presence of a catalyst.

[In the formula, all symbols have the same meaning as defined above. In the formula (I), when R ⁴ , R ⁵ and R ⁶ contain a group having a cyclic carbonate structure, R ⁴ , R ⁵ and R ⁶ in the formula (I-c) may be replaced with —OH.]
The catalyst includes potassium carbonate, sodium hydride, and the like.

Examples of the solvent include chloroform, monochlorobenzene, acetonitrile, and water.
The reaction temperature is usually 15° C. to 100° C., and the reaction time is usually 0.5 hours to 24 hours.

Salts represented by formula (I-e) include salts represented by the following formula, which are readily available on the market.

Compounds represented by formula (I-f1), (I-f2) and (I-f3) include the compounds represented below, which are readily available on the market.

The salt represented by formula (I-c) can also be produced by reacting the salt represented by formula (I-e), the compound represented by formula (I-f4), the compound represented by formula (I-f5), and the compound represented by formula (I-f6) in a solvent in the presence of potassium carbonate, followed by acid treatment.

[In the formula, all symbols have the same meaning as defined above.
R ^ac represents an acid labile group. In the formula (I), when R ⁴ , R ⁵ and R ⁶ each contain a group having a cyclic carbonate structure, R ⁴ , R ⁵ and R ⁶ in the formula (I-c) may be replaced with —OH.]
Examples of the solvent include chloroform, monochlorobenzene, acetonitrile, and water.

The reaction temperature is usually 15° C. to 100° C., and the reaction time is usually 0.5 hours to 24 hours.
The acid includes p-toluenesulfonic acid, hydrochloric acid, and the like.

Compounds represented by formula (I-f4), (I-f5) and (I-f6) include the compounds represented below, which are readily available on the market.

The salt (I-a) in which R ¹ , R ² , and R ³ are *-O-R ¹⁰ (salt represented by formula (I-a2) below) can be produced by reacting the salt represented by formula (I-c) with a compound represented by formula (I-d2) in a solvent in the presence of a base catalyst.

[In the formula, all symbols have the same meaning as defined above. In the formula (I), when R ⁴ , R ⁵ and R ⁶ contain a group having a cyclic carbonate structure, R ⁴ , R ⁵ and R ⁶ in the formula (I-c) may be replaced with —OH.]
The base catalyst includes sodium hydroxide, potassium hydroxide, and the like.

Examples of the solvent include chloroform, monochlorobenzene, dimethylformamide, acetonitrile, ethyl acetate, and water.
The reaction temperature is usually 15° C. to 80° C., and the reaction time is usually 0.5 to 24 hours.

Compounds represented by formula (I-d2) include, for example, the compounds represented below, which are readily available on the market and can also be easily produced by known methods.

In the salt (I-a), a salt in which R ¹ , R ² , and R ³ are *-O-CO-O-R ¹⁰ (a salt represented by the following formula (I-a3)) can be produced by reacting a salt represented by formula (I-c) with a compound represented by formula (I-d2) in a solvent in the presence of carbonyldiimidazole.

[In the formula, all symbols have the same meaning as defined above. In the formula (I), when R ⁴ , R ⁵ and R ⁶ contain a group having a cyclic carbonate structure, R ⁴ , R ⁵ and R ⁶ in the formula (I-c) may be replaced with —OH.]
Examples of the solvent include chloroform, monochlorobenzene, dimethylformamide, acetonitrile, ethyl acetate, and water.

The reaction temperature is usually 15° C. to 80° C., and the reaction time is usually 0.5 to 24 hours.
The salt represented by formula (I-c) can also be produced by reacting a compound represented by formula (If1), a compound represented by formula (If2), and a compound represented by formula (If3) with carbonyldiimidazole in a solvent, and then further reacting the resulting mixture with a salt represented by formula (I-g).

[In the formula, all symbols have the same meaning as defined above. In the formula (I), when R ⁴ , R ⁵ and R ⁶ contain a group having a cyclic carbonate structure, R ⁴ , R ⁵ and R ⁶ in the formula (I-c) may be replaced with —OH.]
Examples of the solvent include chloroform, monochlorobenzene, and acetonitrile.

The reaction temperature is usually 15° C. to 80° C., and the reaction time is usually 0.5 to 24 hours.
Examples of the salt represented by formula (Ie) include the salt represented by the following formula, which are readily available on the market.

The salt (I-a) in which R ¹ , R ² , and R ³ are *-O-CO-R ¹⁰ (salt represented by formula (I-a4) below) can be produced by reacting the salt represented by formula (I-c) with the compound represented by formula (I-h) in a solvent in the presence of a base catalyst.

[In the formula, all symbols have the same meaning as defined above. In the formula (I), when R ⁴ , R ⁵ and R ⁶ contain a group having a cyclic carbonate structure, R ⁴ , R ⁵ and R ⁶ in the formula (I-c) may be replaced with —OH.]
Examples of the base catalyst include potassium carbonate, potassium iodide, pyridine, and triethylamine.

Examples of the solvent include chloroform, monochlorobenzene, dimethylformamide, acetonitrile, ethyl acetate, and water.
The reaction temperature is usually 15° C. to 80° C., and the reaction time is usually 0.5 to 24 hours.

Compounds represented by formula (I-h) include, for example, the compounds represented below, which are readily available on the market and can also be easily produced by known methods.

<Acid Generator>
The acid generator of the present invention is an acid generator containing a salt (I). It may contain one kind of salt (I) or may contain two or more kinds of salts (I).

The acid generator of the present invention may contain, in addition to the salt (I), a known compound that acts as an acid generator in the resist field (hereinafter, sometimes referred to as "compound (B)"). Compound (B) may be used alone or in combination of two or more kinds.

<Compound (B)>
The compound (B) may be either nonionic or ionic. Examples of nonionic acid generators include sulfonate esters (e.g., 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone-4-sulfonate), sulfones (e.g., disulfone, ketosulfone, sulfonyldiazomethane), and the like. Examples of ionic acid generators include onium salts containing onium cations (e.g., diazonium salts, phosphonium salts, sulfonium salts, iodonium salts). Examples of the anions of the onium salts include sulfonate anions, sulfonylimide anions, sulfonylmethide anions, and carboxylate anions.

Compound (B) may be a compound that generates an acid when exposed to radiation, as described in JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, JP-A-62-153853, JP-A-63-146029, U.S. Pat. No. 3,779,778, U.S. Pat. No. 3,849,137, German Patent No. 3914407, European Patent No. 126,712, etc. Compounds produced by known methods may also be used. Compound (B) may be used in combination of two or more types.

Compound (B) is preferably a salt represented by formula (B1) (hereinafter sometimes referred to as "salt (B1)", excluding salt (I)) or a salt represented by formula (B2) (hereinafter sometimes referred to as "salt (B2)", excluding salt (I)).

[In formula (B1),
Q ^b1 and Q ^b2 each independently represent a hydrogen atom, a fluorine atom, an alkyl group having 1 to 6 carbon atoms or a perfluoroalkyl group having 1 to 6 carbon atoms.

L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, in which -CH ₂ - may be replaced by -O- or -CO-, and in which a hydrogen atom may be replaced by a fluorine atom or a hydroxyl group.

Y represents a methyl group which may have a substituent or a cyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, and -CH ₂ - contained in the cyclic hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-.

Z1 ⁺ represents an organic cation.
Q ^b1 , Q ^b2 , L ^b1 and Y in formula (B1) are the same as Q ¹ , Q ² , L ¹ and Y ¹ in formula (IA) above, respectively.

The sulfonate anion in formula (B1) can be the same as the anion represented by formula (I-A).

[In formula (B2),
m21 represents an integer of 1 to 5, and when m21 is 2 or greater, the groups in the parentheses may be the same or different.

R ²¹ represents a hydrocarbon group having 3 to 48 carbon atoms, including a cyclic hydrocarbon group having 3 to 18 carbon atoms, the cyclic hydrocarbon group may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-.

R ²² represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and --CH ₂ -- contained in the alkyl group may be replaced by --O-- or --CO--.
m22 represents an integer of 0 to 4, and when m22 is 2 or greater, multiple R ²² may be the same or different.

Z1 ⁺ represents an organic cation.
In the formula (B2), m21, m22, R ²¹ and R ²² are the same as m21, m22, R ²¹ and R ²² in the formula (IB) described above.

The sulfonate anion in formula (B2) may be the same as the anion represented by formula (IB).
In another embodiment of the compound (B), a salt in which the anion in the salt represented by formula (B1) or the like is replaced with a sulfonylimide anion, a sulfonylmethide anion, a carboxylate anion, or the like, is also preferably used as the compound (B). Examples of the sulfonylimide anion and the sulfonylmethide anion include those similar to those described above. In this case, the salt represented by formula (I) is not included.

Examples of carboxylate anions include:

Examples of the organic cation of Z1 ⁺ include an organic onium cation, an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation, and an organic phosphonium cation. Among these, an organic sulfonium cation and an organic iodonium cation are preferred, and an arylsulfonium cation is more preferred. Specific examples include cations represented by any one of formulas (b2-1) to (b2-4) (hereinafter, sometimes referred to as "cation (b2-1)" depending on the formula number).

[In formulas (b2-1) to (b2-4),
R ^b4 to R ^b6 each independently represent a chain hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, a hydrogen atom contained in the chain hydrocarbon group may be substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, or a glycidyloxy group, and a hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, a fluorinated alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

R ^b4 and R ^b5 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, and —CH ₂ — contained in the ring may be replaced by —O—, —S— or —CO—.

R ^b7 and R ^b8 each independently represent a halogen atom, a hydroxyl group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, a fluorinated alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

m2 and n2 each independently represent an integer of 0 to 5.
When m2 is 2 or more, multiple R ^b7s may be the same or different, and when n2 is 2 or more, multiple R ^b8s may be the same or different.

R ^b9 and R ^b10 each independently represent a chain hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms.
R ^b9 and R ^b10 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, and --CH ₂ -- contained in the ring may be replaced with --O--, --S-- or --CO--.

R ^b11 represents a hydrogen atom, a chain hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^b12 represents an open chain hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, a hydrogen atom contained in the open chain hydrocarbon group may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and a hydrogen atom contained in the aromatic hydrocarbon group may be substituted with an alkoxy group having 1 to 12 carbon atoms or an alkylcarbonyloxy group having 1 to 12 carbon atoms.

R ^b11 and R ^b12 may be bonded to each other to form a ring including the —CH—CO— to which they are bonded, and —CH ₂ — contained in the ring may be replaced by —O—, —S— or —CO—.

R ^b13 to R ^b18 each independently represent a halogen atom, a hydroxyl group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, a fluorinated alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

R ^b13 and R ^b14 may be bonded to each other to form a ring containing a sulfur atom together with the benzene ring to which they are bonded, and —CH ₂ — contained in the ring may be replaced by —O—, —S— or —CO—.

L ^b31 represents a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represent an integer of 0 to 5.
q2 and r2 each independently represent an integer of 0 to 4.

u2 represents 0 or 1.
When o2 is 2 or more, multiple R ^b13 are the same or different, when p2 is 2 or more, multiple R ^b14 are the same or different, when q2 is 2 or more, multiple R ^b15 are the same or different, when r2 is 2 or more, multiple R ^b16 are the same or different, when s2 is 2 or more, multiple R ^b17 are the same or different, and when t2 is 2 or more, multiple R ^b18 are the same or different.
When u2 is 0, it is preferable that any one of o2, p2, q2, and r2 is 1 or more, and at least one of R ^b13 to R ^b16 is a halogen atom; and when u2 is 1, it is preferable that any one of o2, p2, s2, t2, q2, and r2 is 1 or more, and at least one of R ^b13 to R ^b18 is a halogen atom.

Furthermore, when u2 is 0, r2 is preferably 1 or more, and more preferably 1. Furthermore, when u2 is 0 and r2 is 1 or more, R ^b16 is preferably a halogen atom.

The aliphatic hydrocarbon group refers to a chain hydrocarbon group and an alicyclic hydrocarbon group.
Examples of the chain hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl and 2-ethylhexyl groups.

In particular, the chain hydrocarbon groups of R ^b9 to R ^b12 preferably have 1 to 12 carbon atoms.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and cyclodecyl. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl, adamantyl, and norbornyl groups, as well as the following groups:

In particular, the alicyclic hydrocarbon groups of R ^b9 to R ^b12 preferably have 3 to 18 carbon atoms, and more preferably have 4 to 12 carbon atoms.
Examples of the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-methyladamantan-2-yl group, a 2-ethyladamantan-2-yl group, a 2-isopropyladamantan-2-yl group, a methylnorbornyl group, an isobornyl group, etc. In the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group, the total number of carbon atoms in the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.

The term "fluorinated alkyl group" refers to an alkyl group having 1 to 12 carbon atoms and a fluorine atom, such as a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, and a perfluorobutyl group. The number of carbon atoms in the fluorinated alkyl group is preferably 1 to 9, more preferably 1 to 6, and even more preferably 1 to 4.

Examples of aromatic hydrocarbon groups include aryl groups such as phenyl, biphenyl, naphthyl, and phenanthryl. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and examples of such groups include aromatic hydrocarbon groups having a chain hydrocarbon group with 1 to 18 carbon atoms (tolyl, xylyl, cumenyl, mesityl, p-ethylphenyl, p-tert-butylphenyl, 2,6-diethylphenyl, 2-methyl-6-ethylphenyl, etc.) and aromatic hydrocarbon groups having an alicyclic hydrocarbon group with 3 to 18 carbon atoms (p-cyclohexylphenyl, p-adamantylphenyl, etc.). When the aromatic hydrocarbon group has a chain hydrocarbon group or an alicyclic hydrocarbon group, a chain hydrocarbon group with 1 to 18 carbon atoms and an alicyclic hydrocarbon group with 3 to 18 carbon atoms are preferred.

An example of the aromatic hydrocarbon group in which a hydrogen atom is substituted with an alkoxy group is a p-methoxyphenyl group.
Examples of the chain hydrocarbon group in which a hydrogen atom has been substituted with an aromatic hydrocarbon group include aralkyl groups such as a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, and a naphthylethyl group.

Examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy, and dodecyloxy groups.

Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of alkylcarbonyloxy groups include methylcarbonyloxy groups, ethylcarbonyloxy groups, propylcarbonyloxy groups, isopropylcarbonyloxy groups, butylcarbonyloxy groups, sec-butylcarbonyloxy groups, tert-butylcarbonyloxy groups, pentylcarbonyloxy groups, hexylcarbonyloxy groups, octylcarbonyloxy groups, and 2-ethylhexylcarbonyloxy groups.

The ring formed by R ^b4 and R ^b5 bonding to each other together with the sulfur atom to which they are bonded may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. Examples of this ring include rings having 3 to 18 carbon atoms, and preferably rings having 4 to 18 carbon atoms. Examples of the ring containing a sulfur atom include 3- to 12-membered rings, and preferably 3- to 7-membered rings, and examples of such rings include the following rings. * represents a bonding site.

The ring formed by R ^b9 and R ^b10 together may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. This ring may be a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Examples of the ring include a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathiane-4-ium ring.

The ring formed by R ^b11 and R ^b12 together may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. This ring may be a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Examples of the ring include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

Among the cations (b2-1) to (b2-4), the cation (b2-1) is preferred.
Examples of the cation (b2-1) include the following cations.

Examples of the cation (b2-2) include the following cations:

Examples of the cation (b2-3) include the following cations:

Examples of the cation (b2-4) include the following cations:

Compound (B) is a combination of the above-mentioned anions and the above-mentioned organic cations, which can be combined arbitrarily. Compound (B) is preferably a combination of an anion represented by any of formulas (I-a-1) to (I-a-4), (I-a-7) to (I-a-11), (I-a-14) to (I-a-30), (I-a-35) to (I-a-68), and (I-B-1) to (I-B-20) and a cation represented by any of formulas (b2-1), (b2-2), (b2-3), or (b2-4).

Preferably, the compound (B) is represented by the formulas (B1-1) to (B1-105) and (B2-1) to (B2-20), respectively. Among them, those containing an arylsulfonium cation are preferable, and those represented by the formulas (B1-1) to (B1-3), (B1-5) to (B1-7), (B1-11) to (B1-14), (B1-20) to (B1-26), (B1-29), (B1-31) to (B1-105), and (B2-1) to (B2-20) are more preferable.

When salt (I) and compound (B) are contained as acid generators, the ratio of the content of salt (I) to compound (B) (mass ratio; salt (I): compound (B)) is usually 1:99 to 99:1, preferably 2:98 to 98:2, more preferably 5:95 to 95:5, even more preferably 10:90 to 90:10, and particularly preferably 15:85 to 85:15.

In the resist composition of the present invention, the total content of the acid generators (salt (I) and compound (B)) is preferably 0.1% by mass to 45% by mass, more preferably 0.1% by mass to 40% by mass, and even more preferably 1% by mass to 40% by mass, based on the solid content of the resist composition. In addition, the total content of the acid generators (salt (I) and compound (B)) is preferably 1 part by mass to 45 parts by mass, more preferably 1 part by mass to 40 parts by mass, and even more preferably 3 parts by mass to 40 parts by mass, based on 100 parts by mass of the resin (A) described below.

<Resist Composition>
The resist composition of the present invention contains at least an acid generator containing the salt (I) of the present invention. The resist composition of the present invention may contain a resin (hereinafter sometimes referred to as "resin (A)") containing a structural unit having an acid labile group and/or a resin other than the resin (A). Here, the "acid labile group" means a group that has a leaving group and is eliminated by contact with an acid, converting the structural unit into a structural unit having a hydrophilic group (e.g., a hydroxyl group or a carboxyl group).

The resist composition of the present invention preferably contains a quencher such as a salt that generates an acid with a weaker acidity than the acid generated by the acid generator (hereinafter sometimes referred to as "quencher (C)"), and preferably contains a solvent (hereinafter sometimes referred to as "solvent (E)").

<Resin (A)>
Resin (A) contains a structural unit having an acid labile group (hereinafter may be referred to as "structural unit (a1)"). Resin (A) preferably further contains a structural unit other than the structural unit (a1). Examples of structural units other than the structural unit (a1) include a structural unit not having an acid labile group (hereinafter may be referred to as "structural unit (s)"), structural units other than the structural unit (a1) and the structural unit (s) (for example, a structural unit having a halogen atom described below (hereinafter may be referred to as "structural unit (a4)"), a structural unit having a non-leaving hydrocarbon group described below (hereinafter may be referred to as "structural unit (a5)"), a structural unit having an -SO ₂ - group described below (hereinafter may be referred to as "structural unit (a6)"), and other structural units derived from monomers known in the field.

<Structural Unit (a1)>
The structural unit (a1) is derived from a monomer having an acid labile group (hereinafter, may be referred to as "monomer (a1)").

The acid labile group contained in the resin (A) is preferably a group represented by formula (1) (hereinafter also referred to as group (1)) and/or a group represented by formula (2) (hereinafter also referred to as group (2)).

[In formula (1), R ^a1 , R ^a2 and R ^a3 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof, or R ^a1 and R ^a2 bond to each other to form an alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.

ma and na each independently represent 0 or 1, and at least one of ma and na represents 1.
* indicates a binding site.]

[In formula (2), R ^a1' and R ^a2' each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms; R ^a3' represents a hydrocarbon group having 1 to 20 carbon atoms; or R ^a2' and R ^a3' are bonded to each other to form a heterocyclic group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded and X, and -CH ₂ - contained in the hydrocarbon group and the heterocyclic group may be replaced by -O- or -S-.

X represents an oxygen atom or a sulfur atom.
na' represents 0 or 1.
* indicates a binding site.]
Examples of the alkyl group for R ^a1 , R ^a2 and R ^a3 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group and an octyl group.

Examples of the alkenyl group for R ^a1 , R ^a2 and R ^a3 include an ethenyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a tert-butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, an isooctenyl group and a nonenyl group.

The alicyclic hydrocarbon group in R ^a1 , R ^a2 and R ^a3 may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups (* represents a bonding site). The number of carbon atoms in the alicyclic hydrocarbon group in ^{R a1} , R ^a2 and R ^a3 is preferably 3 to 16.

Examples of the aromatic hydrocarbon group for R ^a1 , R ^a2 and R ^a3 include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group and a phenanthryl group.
Examples of the combined group include a group in which the above-mentioned alkyl group and an alicyclic hydrocarbon group are combined (for example, an alkylcycloalkyl group or a cycloalkylalkyl group such as a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group, or a norbornylethyl group), an aralkyl group such as a benzyl group, an aromatic hydrocarbon group having an alkyl group (a p-methylphenyl group, a p-tert-butylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a 2,6-diethylphenyl group, a 2-methyl-6-ethylphenyl group, or the like), an aromatic hydrocarbon group having an alicyclic hydrocarbon group (a p-cyclohexylphenyl group, a p-adamantylphenyl group, or the like), and an aryl-cycloalkyl group such as a phenylcyclohexyl group.

Preferably, ma is 0 and na is 1.
When R ^a1 and R ^a2 are bonded to each other to form an alicyclic hydrocarbon group, examples of -C(R ^a1 )(R ^a2 )(R ^a3 ) include the following groups. The alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * represents the bonding site with -O-.

Examples of the hydrocarbon group for R ^a1' , R ^a2' and R ^a3' include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group and a combination thereof.
Examples of the alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, and group formed by combining these groups include the same groups as those exemplified for R ^a1 , R ^a2 , and R ^a3 .

When R ^a2' and R ^a3' are bonded to each other to form a heterocyclic group together with the carbon atom to which they are bonded and X, -C(R ^a1' )(R ^a2' )-X-R ^a3' includes the following groups: * represents the bonding site with -O-.

At least one of R ^a1' and R ^a2' is preferably a hydrogen atom.
na' is preferably 0.
Examples of the group (1) include the following groups.

A group in which R ^a1 , R ^a2 and R ^a3 in the formula (1) are alkyl groups, ma = 0 and na = 1. As the group, a tert-butoxycarbonyl group is preferable.
A group in which, in the formula (1), R ^a1 and R ^a2 together with the carbon atom to which they are bonded form an adamantyl group, R ^a3 is an alkyl group, ma=0, and na=1.

A group represented by formula (1), in which R ^a1 and R ^a2 each independently represent an alkyl group, R ^a3 represents an adamantyl group, ma=0, and na=1.
Specific examples of the group (1) include the following groups: * represents a binding site.

Specific examples of group (2) include the following groups. * indicates a binding site.

The monomer (a1) is preferably a monomer having an acid labile group and an ethylenically unsaturated bond, more preferably a (meth)acrylic monomer having an acid labile group.
Of the (meth)acrylic monomers having an acid labile group, preferred are those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms. When a resin (A) having a structural unit derived from a monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used in a resist composition, the resolution of the resist pattern can be improved.

The structural unit derived from the (meth)acrylic monomer having group (1) may be a structural unit represented by formula (a1-0) (hereinafter, may be referred to as structural unit (a1-0)), a structural unit represented by formula (a1-1) (hereinafter, may be referred to as structural unit (a1-1)), or a structural unit represented by formula (a1-2) (hereinafter, may be referred to as structural unit (a1-2)). Preferably, it is at least one structural unit selected from the group consisting of structural unit (a1-0), structural unit (a1-1) and structural unit (a1-2), more preferably at least one or two structural units selected from the group consisting of structural unit (a1-1) and structural unit (a1-2). These may be used alone or in combination of two or more.

[In formula (a1-0), formula (a1-1) and formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent --O-- or *-O--(CH ₂ ) _k1 --CO--O--, where k1 represents an integer of 1 to 7, and * represents a bonding site with --CO--.

R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a02 , R ^a03 and R ^a04 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof.

R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these.

m1' represents an integer of 0 to 14.
n1 represents an integer of 0 to 10.
n1' represents an integer of 0 to 3.
R ^a01 , R ^a4 and R ^a5 are preferably a hydrogen atom or a methyl group, more preferably a methyl group.

L ^a01 , L ^a1 and L ^a2 are preferably an oxygen atom or *-O-(CH ₂ ) _k01 -CO-O- (wherein k01 is preferably an integer of 1 to 4, more preferably 1), and more preferably an oxygen atom.

Examples of the alkyl group, alkenyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, and combinations thereof for R ^a02 , R ^a03 , R ^a04 , R ^a6 , and R ^a7 include the same groups as those exemplified for R ^a1 , R ^a2 , and R ^a3 in formula (1).

The alkyl group in R ^a02 , R ^a03 , and R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

The alkyl group for R ^a6 and R ^a7 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group, an isopropyl group, or a t-butyl group, and even more preferably an ethyl group, an isopropyl group, or a t-butyl group.

The alkenyl group for R ^a6 and R ^a7 is preferably an alkenyl group having 2 to 6 carbon atoms, and more preferably an ethenyl group, a propenyl group, an isopropenyl group or a butenyl group.

The alicyclic hydrocarbon group of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 preferably has 5 to 12 carbon atoms, and more preferably 5 to 10 carbon atoms.
The aromatic hydrocarbon groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 preferably have 6 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms.

The group in which an alkyl group and an alicyclic hydrocarbon group are combined preferably has a total carbon number of 18 or less.
The group in which an alkyl group and an aromatic hydrocarbon group are combined preferably has a total carbon number of 18 or less.

R ^a02 and R ^a03 are preferably an alkyl group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and more preferably a methyl group, an ethyl group, a phenyl group or a naphthyl group.

R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, and more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group.

R ^a6 and R ^a7 are preferably an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an aromatic hydrocarbon group having 6 to 12 carbon atoms, more preferably a methyl group, an ethyl group, an isopropyl group, a t-butyl group, an ethenyl group, a phenyl group, or a naphthyl group, and even more preferably an ethyl group, an isopropyl group, a t-butyl group, an ethenyl group, or a phenyl group.

m1' is preferably an integer of 0 to 3, and more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, and more preferably 0 or 1.

n1' is preferably 0 or 1.
Examples of the structural unit (a1-0) include structural units represented by any one of formulas (a1-0-1) to (a1-0-18) and structural units in which a methyl group corresponding to R ^a01 in the structural unit (a1-0) in formulas (a1-0-1) to (a1-0-18) is replaced with a hydrogen atom, a halogen atom, a haloalkyl group (an alkyl group having a halogen atom) or another alkyl group, and structural units represented by any one of formulas (a1-0-1) to (a1-0-10), (a1-0-13) and (a1-0-14) are preferred.

Examples of the structural unit (a1-1) include structural units derived from monomers described in JP-A-2010-204646. Among these, structural units represented by any one of formulas (a1-1-1) to (a1-1-7) and structural units in which the methyl group corresponding to R ^a4 in the structural unit (a1-1) in formulas (a1-1-1) to (a1-1-7) is replaced with a hydrogen atom, a halogen atom, a haloalkyl group or another alkyl group are preferred, and structural units represented by any one of formulas (a1-1-1) to (a1-1-4) are more preferred.

Examples of the structural unit (a1-2) include structural units represented by any one of formulas (a1-2-1) to (a1-2-14) and structural units in which a methyl group corresponding to R ^a5 in the structural unit (a1-2) in formulas (a1-2-1) to (a1-2-14) is replaced with a hydrogen atom, a halogen atom, a haloalkyl group or another alkyl group. Of these, structural units represented by any one of formulas (a1-2-2), (a1-2-5), (a1-2-6), and (a1-2-10) to (a1-2-14) are preferred.

When resin (A) contains structural unit (a1-0) and/or structural unit (a1-1) and/or structural unit (a1-2), the total content of these units relative to the total structural units of resin (A) is 10 mol% or more, preferably 15 mol% or more, more preferably 20 mol% or more, even more preferably 25 mol% or more, and even more preferably 30 mol% or more. Also, 95 mol% or less, preferably 90 mol% or less, more preferably 85 mol% or less, and even more preferably 70 mol% or less. Specifically, 10 to 95 mol% is included, preferably 15 to 90 mol%, more preferably 20 to 85 mol%, even more preferably 25 to 70 mol%, and even more preferably 30 to 70 mol%.

When resin (A) contains structural unit (a1-0), its content is 5 mol% or more, preferably 10 mol% or more, based on the total structural units of resin (A). It can also be 80 mol% or less, preferably 75 mol% or less, and more preferably 70 mol% or less. Specifically, it can be 5 to 80 mol%, preferably 5 to 75 mol%, and more preferably 10 to 70 mol%.

When resin (A) contains structural unit (a1-1) and/or structural unit (a1-2), the total content of these units relative to the total structural units of resin (A) is 10 mol% or more, preferably 15 mol% or more, more preferably 20 mol% or more, even more preferably 25 mol% or more, and even more preferably 30 mol% or more. Also, 95 mol% or less, preferably 90 mol% or less, more preferably 85 mol% or less, even more preferably 80 mol% or less, even more preferably 75 mol% or less, and even more preferably 70 mol% or less. Specifically, 10 to 90 mol% is included, preferably 15 to 85 mol%, more preferably 15 to 80 mol%, even more preferably 20 to 80 mol%, even more preferably 20 to 75 mol%, and even more preferably 20 to 70 mol%.

An example of the structural unit (a1) having group (2) is the structural unit represented by formula (a1-4) (hereinafter, sometimes referred to as "structural unit (a1-4)").

[In formula (a1-4),
R ^a32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.

R ^a33 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or a methacryloyloxy group.

A ^a30 represents a single bond or *-X ^a31 -(A ^a32 -X ^a32 ) _nc -, where * represents the bonding site with the carbon atom to which -R ^a32 is bonded.
A ^a32 represents an alkanediyl group having 1 to 8 carbon atoms.

X ^a31 and X ^a32 each independently represent -O-, -CO-O- or -O-CO-.
n c represents 0 or 1.

la represents an integer of 0 to 4. When la is an integer of 2 or more, multiple R ^a33 may be the same or different.
R ^a34 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a36 represents a hydrocarbon group having 1 to 20 carbon atoms, or R ^a35 and R ^a36 are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms together with the -C-O- to which they are bonded, and the -CH ₂ - contained in the hydrocarbon group and the divalent hydrocarbon group may be replaced by -O- or -S-.]
Examples of the halogen atom in R ^a32 and R ^a33 include a fluorine atom, a chlorine atom, and a bromine atom.

Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom for R ^a32 include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a propyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a butyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, a hexyl group, and a perfluorohexyl group.

R ^a32 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group.
Examples of the alkyl group for R ^a33 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.

Examples of the alkoxy group in R ^a33 include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group, and a hexyloxy group. The alkoxy group is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and further preferably a methoxy group.

Examples of the alkoxyalkyl group for R ^a33 include a methoxymethyl group, an ethoxyethyl group, a propoxymethyl group, an isopropoxymethyl group, a butoxymethyl group, a sec-butoxymethyl group, and a tert-butoxymethyl group. The alkoxyalkyl group is preferably an alkoxyalkyl group having 2 to 8 carbon atoms, more preferably a methoxymethyl group or an ethoxyethyl group, and further preferably a methoxymethyl group.

Examples of the alkoxyalkoxy group for R ^a33 include a methoxymethoxy group, a methoxyethoxy group, an ethoxymethoxy group, an ethoxyethoxy group, a propoxymethoxy group, an isopropoxymethoxy group, a butoxymethoxy group, a sec-butoxymethoxy group, and a tert-butoxymethoxy group. The alkoxyalkoxy group is preferably an alkoxyalkoxy group having 2 to 8 carbon atoms, and more preferably a methoxyethoxy group or an ethoxyethoxy group.

Examples of the alkylcarbonyl group for R ^a33 include an acetyl group, a propionyl group, a butyryl group, etc. The alkylcarbonyl group is preferably an alkylcarbonyl group having 2 to 3 carbon atoms, and more preferably an acetyl group.

The alkylcarbonyloxy group for R ^a33 includes an acetyloxy group, a propionyloxy group, and a butyryloxy group. The alkylcarbonyloxy group is preferably an alkylcarbonyloxy group having 2 to 3 carbon atoms, and more preferably an acetyloxy group.

R ^a33 is preferably a halogen atom, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxyalkoxy group having 2 to 8 carbon atoms, more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group, or an ethoxymethoxy group, and even more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, or an ethoxyethoxy group.

Examples of *-X ^a31 -(A ^a32 -X ^a32 ) _nc - include *-O-, *-CO-O-, *-O-CO-, *-CO-O-A ^a32 -CO-O-, *-O-CO-A ^a32 -O-, *-O-A ^a32 -CO-O-, *-CO-O-A ^a32 -O-CO-, and *-O-CO-A ^a32 -O-CO-. Among these, *-CO-O-, *-CO-O-A ^a32 -CO-O- or *-O-A ^a32 -CO-O- are preferred.

Examples of the alkanediyl group in A ^a32 include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group.

A ^a32 is preferably a methylene group or an ethylene group.
A ^a30 is preferably a single bond, *-CO-O- or *-CO-O-A ^a32 -CO-O-, more preferably a single bond, *-CO-O- or *-CO-O-CH ₂ -CO-O-, further preferably a single bond or *-CO-O-.

la is preferably 0, 1 or 2, more preferably 0 or 1, and even more preferably 0.
The hydrocarbon group for R ^a34 , R ^a35 and R ^a36 includes an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group and a combination thereof.

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl, adamantyl, and norbornyl groups, as well as the following groups (* indicates a bonding site):

Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, and a phenanthryl group.
Examples of the group combining an alkyl group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group include a group combining the above-mentioned alkyl group and an alicyclic hydrocarbon group (e.g., an alkylcycloalkyl group or a cycloalkylalkyl group such as a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group, or a norbornylethyl group), an aralkyl group such as a benzyl group, an aromatic hydrocarbon group having an alkyl group (p-methylphenyl group, a p-tert-butylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a 2,6-diethylphenyl group, a 2-methyl-6-ethylphenyl group, or the like), an aromatic hydrocarbon group having an alicyclic hydrocarbon group (p-cyclohexylphenyl group, a p-adamantylphenyl group, or the like), and an aryl-cycloalkyl group such as a phenylcyclohexyl group. In particular, examples of R ^a36 include an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group combining these.

R ^a34 is preferably a hydrogen atom.
R ^a35 is preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a methyl group or an ethyl group.

The hydrocarbon group of R ^a36 is preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these, and more preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms. The alkyl group and alicyclic hydrocarbon group of R ^a36 are preferably unsubstituted. The aromatic hydrocarbon group of R ^a36 is preferably an aromatic ring having an aryloxy group having 6 to 10 carbon atoms.

--OC(R ^a34 )(R ^a35 )--O--R ^a36 in the structural unit (a1-4) is eliminated upon contact with an acid (eg, p-toluenesulfonic acid) to form a hydroxy group.
--OC(R ^a34 )(R ^a35 )--O--R ^a36 is preferably bonded to the o-position or p-position of the benzene ring, and more preferably bonded to the p-position.

Examples of the structural unit (a1-4) include structural units derived from monomers described in JP-A-2010-204646. Preferred examples include structural units represented by formulas (a1-4-1) to (a1-4-24) and structural units in which the hydrogen atom corresponding to R ^a32 in the structural unit (a1-4) is replaced with a halogen atom, a haloalkyl group, or an alkyl group, and more preferred examples include structural units represented by formulas (a1-4-1) to (a1-4-5), (a1-4-10), (a1-4-13), (a1-4-14), (a1-4-19), and (a1-4-20).

When resin (A) contains structural unit (a1-4), its content is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, even more preferably 20 to 85 mol%, even more preferably 20 to 70 mol%, and even more preferably 20 to 60 mol%, based on the total of all structural units in resin (A).

An example of a structural unit derived from a (meth)acrylic monomer having group (2) is a structural unit represented by formula (a1-5) (hereinafter sometimes referred to as "structural unit (a1-5)").

[In formula (a1-5),
R ^a8 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.

Z ^a1 represents a single bond or *-(CH ₂ ) _h3 -CO-L ⁵⁴ -, where h3 represents an integer of 1 to 4, and * represents the bonding site to L ⁵¹ .
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ each independently represent --O-- or --S--.

s1 represents an integer of 1 to 3.
s1' represents an integer of 0 to 3.
Examples of the halogen atom include a fluorine atom and a chlorine atom, with a fluorine atom being preferred.

Examples of alkyl groups having 1 to 6 carbon atoms that may have a halogen atom include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, fluoromethyl, and trifluoromethyl groups.

In formula (a1-5), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.

It is preferable that one of L ⁵² and L ⁵³ is —O— and the other is —S—.
It is preferable that s1 is 1.
s1' is preferably an integer of 0 to 2.

Z ^a1 is preferably a single bond or *-CH ₂ -CO-O-.
Examples of the structural unit (a1-5) include structural units derived from monomers described in JP-A-2010-61117. Among these, the structural units represented by formulae (a1-5-1) to (a1-5-4) are preferred, and the structural unit represented by formula (a1-5-1) or (a1-5-2) is more preferred.

When resin (A) contains structural unit (a1-5), its content is preferably 1 to 50 mol %, more preferably 3 to 45 mol %, even more preferably 5 to 40 mol %, and even more preferably 5 to 30 mol %, based on the total structural units of resin (A).

Further examples of the structural unit (a1) include the following structural units:

When resin (A) contains structural units such as (a1-3-1) to (a1-3-7), the content thereof is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, even more preferably 20 to 85 mol%, even more preferably 20 to 70 mol%, and particularly preferably 20 to 60 mol%, based on the total structural units of resin (A).

<Structural unit (s)>
The structural unit (s) is derived from a monomer having no acid labile group (hereinafter, may be referred to as "monomer (s)"). As the monomer from which the structural unit (s) is derived, a monomer having no acid labile group known in the resist field can be used.

The structural unit (s) preferably has a hydroxy group or a lactone ring. If a resin containing a structural unit having a hydroxy group and no acid labile group (hereinafter sometimes referred to as "structural unit (a2)") and/or a structural unit having a lactone ring and no acid labile group (hereinafter sometimes referred to as "structural unit (a3)") is used in the resist composition of the present invention, the resolution of the resist pattern and adhesion to the substrate can be improved.

<Structural unit (a2)>
The structural unit (a2) is a structural unit represented by formula (a2) and has an alcoholic hydroxy group or a phenolic hydroxy group.

[In formula (a2),
R ^a50 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.

A ^a50 represents a single bond or *-X ^a51 -(A ^a52 -X ^a52 ) _nb -, where * represents the bonding site with the carbon atom to which -R ^a50 is bonded.
A ^a52 represents an alkanediyl group having 1 to 8 carbon atoms.

X ^a51 and X ^a52 each independently represent -O-, -CO-O- or -O-CO-.
nb represents 0 or 1.

W ^a50 represents a cyclic hydrocarbon group having 5 to 12 carbon atoms which may have a substituent.
L ^a50 represents a single bond or a chain hydrocarbon group having 1 to 12 carbon atoms which may have a fluorine atom.

ma50 represents an integer of 1 to 5.
Examples of the halogen atom in R ^a50 include a fluorine atom, a chlorine atom, and a bromine atom.

Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom in R ^a50 include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a propyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a butyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, a hexyl group, and a perfluorohexyl group. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2.

R ^a50 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group.
Examples of the alkanediyl group of A ^a52 in A ^a50 include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group, etc. The number of carbon atoms in the alkanediyl group is preferably 1 to 6, more preferably 1 to 4, even more preferably 1 to 3, and even more preferably 1 or 2.

A ^a52 is preferably a methylene group or an ethylene group.
Examples of *-X ^a51 -(A ^a52 -X ^a52 ) _nb - include *-O-, *-CO-O-, *-O-CO-, *-CO-O-A ^a52 -CO-O-, *-O-CO-A ^a52 -O-, *-O-A ^a52 -CO-O-, *-CO-O-A ^a52 -O-CO-, and *-O-CO-A ^a52 -O-CO-. Among these, *-CO-O-, *-CO-O-A ^a52 -CO-O- or *-O-A ^a52 -CO-O- are preferred.

A ^a50 is preferably a single bond, *-CO-O- or *-CO-O-A ^a52 -CO-O-, more preferably a single bond, *-CO-O- or *-CO-O-CH ₂ -CO-O-, further preferably a single bond or *-CO-O-.

Examples of the cyclic hydrocarbon group for W ^a50 include a divalent alicyclic hydrocarbon group and a divalent aromatic hydrocarbon group.
Examples of the divalent monocyclic alicyclic hydrocarbon group in W ^a50 include monocyclic cycloalkanediyl groups such as cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, and cyclooctane-1,5-diyl group. Examples of the divalent polycyclic alicyclic hydrocarbon group include polycyclic cycloalkanediyl groups such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, and adamantane-2,6-diyl group. The number of carbon atoms in the alicyclic hydrocarbon group is preferably 6 to 12, and more preferably 6 to 10.

The divalent aromatic hydrocarbon group in W ^a50 may be a phenylene group or a naphthylene group. The aromatic hydrocarbon group preferably has 6 to 12 carbon atoms, more preferably 6 to 10 carbon atoms.

Examples of the substituent that the cyclic hydrocarbon group having 5 to 12 carbon atoms of W ^a50 may have include a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, a haloalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or a methacryloyloxy group, etc. The number of substituents that W ^a50 has may be one or more.

Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. The number of carbon atoms in the alkyl group is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

Examples of haloalkyl groups include trifluoromethyl, difluoromethyl, perfluoroethyl, 2,2,2-trifluoroethyl, 1,1,2,2-tetrafluoroethyl, perfluoropropyl, 2,2,3,3,3-pentafluoropropyl, perfluorobutyl, 1,1,2,2,3,3,4,4-octafluorobutyl, perfluoropentyl, 2,2,3,3,4,4,5,5,5-nonafluoropentyl, perfluorohexyl, chloromethyl, bromomethyl, and iodomethyl. The number of carbon atoms in the haloalkyl group is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3.

Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, and a tert-butoxy group. The number of carbon atoms in the alkoxy group is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3. The alkoxy group is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and even more preferably a methoxy group.

Examples of the alkoxyalkyl group include a methoxymethyl group, an ethoxyethyl group, a propoxymethyl group, an isopropoxymethyl group, a butoxymethyl group, a sec-butoxymethyl group, and a tert-butoxymethyl group. The alkoxyalkyl group is preferably an alkoxyalkyl group having 2 to 8 carbon atoms, more preferably a methoxymethyl group or an ethoxyethyl group, and even more preferably a methoxymethyl group.

Examples of the alkoxyalkoxy group include a methoxymethoxy group, a methoxyethoxy group, an ethoxymethoxy group, an ethoxyethoxy group, a propoxymethoxy group, an isopropoxymethoxy group, a butoxymethoxy group, a sec-butoxymethoxy group, and a tert-butoxymethoxy group. The alkoxyalkoxy group is preferably an alkoxyalkoxy group having 2 to 8 carbon atoms, and more preferably a methoxyethoxy group or an ethoxyethoxy group.

Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group. The alkylcarbonyl group is preferably an alkylcarbonyl group having 2 to 3 carbon atoms, and more preferably an acetyl group.

Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, and a butyryloxy group. The alkylcarbonyloxy group is preferably an alkylcarbonyloxy group having 2 to 3 carbon atoms, and more preferably an acetyloxy group.

The substituent of the cyclic hydrocarbon group for W ^a50 is preferably a halogen atom, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxyalkoxy group having 2 to 8 carbon atoms, more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group, or an ethoxymethoxy group, and even more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, or an ethoxyethoxy group.

Examples of the chain hydrocarbon group having 1 to 12 carbon atoms for L ^a50 include linear alkanediyl groups such as methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, and dodecane-1,12-diyl group; ethane-1,1-diyl group, propane-1, Examples of branched alkanediyl groups include a 1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a 1-methylpropane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a 1-dimethylpropane-1,3-diyl group, a pentane-2,4-diyl group, a pentane-1,4-diyl group, a 2-methylbutane-1,4-diyl group, a pentane-2,4-diyl group, a pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group.

The chain hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, further preferably 1 to 6 carbon atoms, and even further preferably 1 to 4 carbon atoms.
The number of fluorine atoms contained in L ^a50 may be one or more.

ma50 is preferably an integer of 1 to 4, and more preferably an integer of 1 to 3.
When a resist pattern is produced from the resist composition of the present invention, in the case where a high energy ray such as a KrF excimer laser (248 nm), an electron beam, or EUV (extreme ultraviolet light) is used as an exposure light source, the structural unit (a2) having a phenolic hydroxyl group is preferred, and it is more preferred to use the structural unit (a2-A) described below. In addition, in the case where an ArF excimer laser (193 nm) or the like is used, the structural unit (a2) having an alcoholic hydroxyl group is preferred, and it is more preferred to use the structural unit (a2-1) described below. The structural unit (a2) may contain one type alone, or may contain two or more types.

An example of the structural unit (a2) having a phenolic hydroxy group is the structural unit represented by formula (a2-A) (hereinafter sometimes referred to as "structural unit (a2-A)").

[In formula (a2-A),
R ^a50 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.

R ^a51 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or a methacryloyloxy group.

A ^a50 represents a single bond or *-X ^a51 -(A ^a52 -X ^a52 ) _nb -, where * represents the bonding site with the carbon atom to which -R ^a50 is bonded.
A ^a52 represents an alkanediyl group having 1 to 8 carbon atoms.

X ^a51 and X ^a52 each independently represent —O—, —CO—O— or —O—CO—.
nb represents 0 or 1.
mb represents an integer of 0 to 4. When mb is an integer of 2 or more, multiple R ^a51 may be the same or different.
R ^a50 and A ^a50 each include the same groups as those exemplified in formula (a2).

Examples of the halogen atom in R ^a51 include a fluorine atom, a chlorine atom, and a bromine atom.
Examples of the alkyl group for R ^a51 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.

Examples of the alkoxy group for R ^a51 include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, and a tert-butoxy group. The alkoxy group is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and even more preferably a methoxy group.

Examples of the alkoxyalkyl group for R ^a51 include a methoxymethyl group, an ethoxyethyl group, a propoxymethyl group, an isopropoxymethyl group, a butoxymethyl group, a sec-butoxymethyl group, and a tert-butoxymethyl group. The alkoxyalkyl group is preferably an alkoxyalkyl group having 2 to 8 carbon atoms, more preferably a methoxymethyl group or an ethoxyethyl group, and even more preferably a methoxymethyl group.

Examples of the alkoxyalkoxy group in R ^a51 include a methoxymethoxy group, a methoxyethoxy group, an ethoxymethoxy group, an ethoxyethoxy group, a propoxymethoxy group, an isopropoxymethoxy group, a butoxymethoxy group, a sec-butoxymethoxy group, and a tert-butoxymethoxy group. The alkoxyalkoxy group is preferably an alkoxyalkoxy group having 2 to 8 carbon atoms, and more preferably a methoxyethoxy group or an ethoxyethoxy group.

Examples of the alkylcarbonyl group for R ^a51 include an acetyl group, a propionyl group, a butyryl group, etc. The alkylcarbonyl group is preferably an alkylcarbonyl group having 2 to 3 carbon atoms, and more preferably an acetyl group.

The alkylcarbonyloxy group for R ^a51 includes an acetyloxy group, a propionyloxy group, and a butyryloxy group. The alkylcarbonyloxy group is preferably an alkylcarbonyloxy group having 2 to 3 carbon atoms, and more preferably an acetyloxy group.

R ^a51 is preferably a halogen atom, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxyalkoxy group having 2 to 8 carbon atoms, more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group, or an ethoxymethoxy group, and still more preferably a fluorine atom, an iodine atom, a hydroxy group, a methyl group, a methoxy group, or an ethoxyethoxy group.

mb is preferably 0, 1 or 2, and more preferably 0 or 1.
At least one hydroxy group is preferably bonded to the meta or para position of the benzene ring. When two hydroxy groups are bonded to a phenyl group, each hydroxy group is preferably bonded to the meta and para positions.

Examples of the structural unit (a2-A) include structural units derived from monomers described in JP-A-2010-204634 and JP-A-2012-12577.
Examples of the structural unit (a2-A) include structural units represented by formulas (a2-2-1) to (a2-2-24) and structural units in which the methyl group corresponding to R ^{a50 in the structural unit (a2-A) is replaced with a hydrogen atom, a halogen atom, a haloalkyl group, or another alkyl group in the structural units represented by formulas (a2-2-1) to (a2-2-24)} . The structural unit (a2-A) is a structural unit represented by the formulas (a2-2-1) to (a2-2-4), a structural unit represented by the formula (a2-2-6), a structural unit represented by the formula (a2-2-8), a structural unit represented by the formulas (a2-2-12) to (a2-2-18), and a structural unit represented by the formulas (a2-2-1) to (a2-2-4), a structural unit represented by the formula (a2-2-6), a structural unit represented by the formula (a2-2-8), and a structural unit represented by the formulas (a2-2-12) to (a2-2-18). It is preferable that the structural unit (a2-A) is a structural unit in which the methyl group corresponding to ^a50 is replaced with a hydrogen atom, and in the structural unit represented by formula (a2-2-3), the structural unit represented by formula (a2-2-4), the structural unit represented by formula (a2-2-8), the structural unit represented by formula (a2-2-12) to formula (a2-2-14), the structural unit represented by formula (a2-2-18), and the structural unit represented by formula (a2-2-3), the structural unit represented by formula (a2-2-4), the structural unit represented by formula (a2-2-8), the structural unit represented by formula (a2-2-12) to formula (a2-2-14), and the structural unit represented by formula (a2-2-18), A structural unit in which a methyl group corresponding to ^a50 is replaced with a hydrogen atom is more preferable, and a structural unit represented by formula (a2-2-3), a structural unit represented by formula (a2-2-4), a structural unit represented by formula (a2-2-8), and a structural unit in which a methyl group corresponding to R ^a50 in the structural unit (a2-A) is replaced with a hydrogen atom is even more preferable.

When the structural unit (a2-A) is contained in the resin (A), the content of the structural unit (a2-A) relative to all structural units is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and even more preferably 20 mol% or more. It is also preferably 80 mol% or less, more preferably 70 mol% or less, and even more preferably 65 mol% or less. Specifically, it is preferably 5 to 80 mol%, more preferably 10 to 70 mol%, even more preferably 15 to 65 mol%, and even more preferably 20 to 65 mol%.

The structural unit (a2-A) can be incorporated into the resin (A) by, for example, polymerizing the structural unit (a1-4) and then treating with an acid such as p-toluenesulfonic acid. Alternatively, the structural unit (a2-A) can be incorporated into the resin (A) by polymerizing the structural unit (a1-4) and then treating with an alkali such as tetramethylammonium hydroxide.

Examples of the structural unit (a2-A) include a structural unit represented by the following formula (a2-A1) (hereinafter sometimes referred to as "structural unit (a2-A1)") and a structural unit represented by the following formula (a2-A2) (hereinafter sometimes referred to as "structural unit (a2-A2)").

[In formula (a2-A1) and formula (a2-A2),
R ^a50 and A ^a50 each have the same meaning as in formula (a2).
mb1 represents an integer of 0 to 4.

R ^a52 represents a halogen atom.
R ^a53 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or a methacryloyloxy group.

mb2 and mb3 each independently represent an integer of 0 to 4, and when mb2 is 2 or greater, multiple R ^a52 may be the same as or different from each other, and when mb3 is 2 or greater, multiple R ^a53 may be the same as or different from each other, and 1≦mb2+mb3≦4 is satisfied.
Examples of the halogen atom of R ^a52 include the same as the substituent of the cyclic hydrocarbon group of W ^a50 and the halogen atom of R ^a51 . The halogen atom of R ^a52 is preferably a fluorine atom or an iodine atom.

Examples of the ^alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, the alkoxyalkyl group having 2 to 12 carbon atoms, the alkoxyalkoxy group having 2 to 12 carbon atoms, the alkylcarbonyl group having 2 to 4 carbon atoms, the alkylcarbonyloxy group having 2 to 4 carbon atoms, the acryloyloxy group or the methacryloyloxy group of R ^a53 include the same as the alkyl group, the alkoxyalkyl group, the alkoxyalkoxy group, the alkylcarbonyl group, the alkylcarbonyloxy group, the acryloyloxy group or the methacryloyloxy group of R ^a51 , respectively, and a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group or an ethoxymethoxy group is more preferable, and a methoxy group or an ethoxyethoxy group is even more preferable.

mb1 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and further preferably 0 or 1.
mb2 is preferably an integer of 0 to 3, more preferably an integer of 1 to 3, and further preferably 1 or 2.

mb3 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and further preferably 0 or 1.
An example of the structural unit (a2) having an alcoholic hydroxy group is a structural unit represented by formula (a2-1) (hereinafter sometimes referred to as "structural unit (a2-1)").

[In formula (a2-1),
L ^a3 represents —O— or *—O—(CH ₂ ) _k2 —CO—O—;
k2 represents an integer of 1 to 7. * represents a bonding site with —CO—.

R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.

o1 represents an integer of 0 to 10.
In formula (a2-1), L ^a3 is preferably —O—, —O—(CH ₂ ) _f1 —CO—O— (wherein f1 represents an integer of 1 to 4), and more preferably —O—.

R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.

o1 is preferably an integer of 0 to 3, and more preferably 0 or 1.
Examples of the structural unit (a2-1) include structural units derived from monomers described in JP 2010-204646 A. A structural unit represented by any one of formulas (a2-1-1) to (a2-1-6) is preferred, a structural unit represented by any one of formulas (a2-1-1) to (a2-1-4) is more preferred, and a structural unit represented by formula (a2-1-1) or formula (a2-1-3) is even more preferred.

When resin (A) contains structural unit (a2-1), its content can be 1 mol% or more, preferably 2 mol% or more, based on the total structural units of resin (A). It can also be 45 mol% or less, preferably 40 mol% or less, more preferably 35 mol% or less, even more preferably 20 mol% or less, and even more preferably 10 mol% or less. Specifically, it can be 1 to 45 mol%, preferably 1 to 40 mol%, more preferably 1 to 35 mol%, even more preferably 1 to 20 mol%, and even more preferably 1 to 10 mol%.

An example of the structural unit (a2) having an alcoholic hydroxyl group is the structural unit represented by formula (a2-B) (hereinafter, sometimes referred to as "structural unit (a2-B)").

[In formula (a2-B),
R ^a50 and A ^a50 each have the same meaning as in formula (a2).
R ^a54 and R ^a55 each independently represent a fluorinated alkyl group having 1 to 4 carbon atoms.

L ^a51 represents a single bond or an alkanediyl group having 1 to 3 carbon atoms, and the alkanediyl group may be substituted with a fluorine atom.
R ^a56 represents a halogen atom, a hydroxy group, a haloalkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 12 carbon atoms, and --CH ₂ -- contained in the alkyl group may be replaced by --O-- or --CO--.

mb4 represents an integer of 1 to 3, and when mb4 is 2 or greater, a plurality of R ^a54 , R ^a55 and L ^a51 may be the same or different.
mb5 represents an integer of 0 to 4, and when mb5 is 2 or more, multiple R ^a56 may be the same or different from each other, provided that 1≦mb4+mb5≦5.
Examples of the fluorinated alkyl group having 1 to 4 carbon atoms for R ^a54 and R ^a55 each independently include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoropropyl group, a 4,4,4-trifluorobutyl group, etc. R ^a54 and R ^a55 are preferably a trifluoromethyl group.

Examples of the alkanediyl group having 1 to 3 carbon atoms for L ^a51 include a methylene group, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-2,2-diyl group, etc. L ^a51 is preferably a single bond or a methylene group.

Examples of the halogen atom for R ^a56 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
The haloalkyl group having 1 to 4 carbon atoms in R ^a56 represents an alkyl group having 1 to 4 carbon atoms and a halogen atom, and examples thereof include a chloromethyl group, a bromomethyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, and a perfluorobutyl group.

Examples of the alkyl group having 1 to 12 carbon atoms in R ^a56 include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a nonyl group, etc. The number of carbon atoms in the alkyl group is preferably 1 to 9, more preferably 1 to 6, and further preferably 1 to 4.

When --CH ₂ -- contained in the alkyl group represented by R ^a56 is replaced by --O-- or --CO--, the number of carbon atoms before replacement is regarded as the total number of carbon atoms in the alkyl group. In addition, R ^a56 may have a hydroxy group (a group in which -CH ₂ - in a methyl group is replaced with -O-), a carboxyl group (a group in which -CH ₂ -CH ₂ - in an ethyl group is replaced with -O-CO-), an alkoxy group having 1 to 11 carbon atoms (a group in which -CH ₂ - in an alkyl group having 2 to 12 carbon atoms is replaced with -O-), an alkoxycarbonyl group having 2 to 11 carbon atoms (a group in which -CH ₂ -CH ₂ - in an alkyl group having 3 to 12 carbon atoms is replaced with -O-CO-), an alkylcarbonyl group having 2 to 12 carbon atoms (a group in which -CH ₂ - in an alkyl group having 2 to 12 carbon atoms is replaced with -CO-), or an alkylcarbonyloxy group having 2 to 11 carbon atoms (a group in which -CH ₂ -CH ₂ - in an alkyl group having 3 to 12 carbon atoms is replaced with -CO-O-).

Among these, R ^a56 is preferably a halogen atom, a haloalkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 12 carbon atoms (-CH ₂ - contained in the alkyl group may be replaced by -O- or -CO-).

mb4 is preferably 1 or 2, and more preferably 1. Even more preferably, mb4 is 1 and the group in the parentheses is bonded to the para position.
mb5 is preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0.

It is more preferable that the structural unit (a2-B) is a structural unit represented by the following formula (a2-B1) (hereinafter, sometimes referred to as "structural unit (a2-B1)").

[In formula (a2-B1),
R ^a57 represents a hydrogen atom or a methyl group.
A ^a53 represents a single bond or ^* -CO-O-, and * represents the bonding site with the carbon atom to which -R ^a57 is bonded.

R ^a56 , mb4 and mb5 each have the same meaning as in formula (a2-B).
In formula (a2-B1), R ^a57 is preferably a hydrogen atom.
A ^a53 is preferably a single bond.

Examples of the structural unit (a2-B) include the structural units listed below.

Specific examples of the structural unit (a2-B) include structural units represented by formulae (a2-B-1) to (a2-B-8) in which the hydrogen atom corresponding to R ^a57 is replaced with a methyl group, and structural units represented by formulae (a2-B-9) to (a2-B-16) in which the methyl group corresponding to R ^a57 is replaced with a hydrogen atom. Among these, the structural units represented by formulae (a2-B-1) to (a2-B-8) are preferred, the structural units represented by formulae (a2-B-1) to (a2-B-4) are more preferred, and the structural unit represented by formula (a2-B-1) is even more preferred.

When resin (A) contains structural unit (a2-B), its content is preferably 3 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, based on the total structural units of resin (A). It is also preferably 80 mol% or less, more preferably 75 mol% or less, even more preferably 70 mol% or less, and even more preferably 65 mol% or less. Specifically, it is preferably 3 to 80 mol%, more preferably 5 to 75 mol%, even more preferably 10 to 70 mol%, and even more preferably 10 to 65 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be a monocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ring, or a δ-valerolactone ring, or may be a condensed ring of a monocyclic lactone ring with another ring. Preferred examples include a γ-butyrolactone ring, an adamantane lactone ring, or a bridged ring containing a γ-butyrolactone ring structure (for example, a structural unit represented by the following formula (a3-2)).

The structural unit (a3) is preferably a structural unit represented by formula (a3-1), formula (a3-2), formula (a3-3) or formula (a3-4). One of these may be contained alone, or two or more of them may be contained.

[In formula (a3-1), formula (a3-2), formula (a3-3) and formula (a3-4),
L ^a4 , L ^a5 and L ^a6 each independently represent a group represented by —O— or *-O-(CH ₂ ) _k3 —CO—O- (k3 represents an integer of any one of 1 to 7).

L ^a7 represents -O-, *-OL ^a8 -O-, *-OL ^a8 -CO-O-, *-OL ^a8 -CO-OL ^a9 -CO-O- or *-OL ^a8 -O-CO-L ^a9 -O-.

L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
* indicates the bonding site with the carbonyl group.
R ^a18 , R ^a19 , R ^a20 and R ^a24 each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.

X ^a3 represents —CH ₂ — or an oxygen atom.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
R ^a22 , R ^a23 and R ^a25 each independently represent a carboxy group, a cyano group or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.

p1 represents an integer of 0 to 5.
q1 represents an integer of 0 to 3.
r1 represents an integer of 0 to 3.

w1 represents an integer of 0 to 8.
When p1, q1, r1 and/or w1 is 2 or more, a plurality of R ^a21 , R ^a22 , R ^a23 and/or R ^a25 may be the same as or different from each other.
Examples of the aliphatic hydrocarbon group for R ^a21 , R ^a22 , R ^a23 and R ^a25 include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group and a tert-butyl group.

The halogen atom for R ^a18 , R ^a19 , R ^a20 and R ^a24 includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkyl group for R ^a18 , R ^a19 , R ^a20 , and R ^a24 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group, and are preferably alkyl groups having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.

Examples of the alkyl group having a halogen atom for R ^a18 , R ^a19 , R ^a20 , and R ^a24 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, a perfluorohexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.

Examples of the alkanediyl group in L ^a8 and L ^a9 include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group.

In formulae (a3-1) to (a3-3), L ^a4 to L ^a6 each independently represent preferably —O— or *-O-(CH ₂ ) _k3 -CO-O-, where k3 is an integer from 1 to 4, more preferably —O— and *-O-CH ₂ -CO-O-, and still more preferably an oxygen atom.

R ^a18 to R ^a21 are preferably methyl groups.
R ^a22 and R ^a23 each independently preferably represent a carboxy group, a cyano group, or a methyl group.

p1, q1 and r1 each independently represent preferably any integer of 0 to 2, and more preferably 0 or 1.
In formula (a3-4), R ^a24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group.

R ^a25 is preferably a carboxy group, a cyano group or a methyl group.
L ^a7 is preferably —O— or *-OL ^a8 —CO—O—, and more preferably —O—, —O—CH ₂ —CO—O— or —O—C ₂ H ₄ —CO—O—.

w1 is preferably an integer of 0 to 2, and more preferably 0 or 1.
In particular, the formula (a3-4) is preferably the formula (a3-4)'.

(In formula (a3-4)′, R ^a24 and L ^a7 have the same meanings as above.)
Examples of the structural unit (a3) include structural units derived from monomers described in JP-A-2010-204646, JP-A-2000-122294, and JP-A-2012-41274. As the structural unit (a3), structural units represented by any one of formulas (a3-1-1), (a3-1-2), (a3-2-1), (a3-2-2), (a3-3-1), (a3-3-2), and (a3-4-1) to (a3-4-12), and structural units in which methyl groups corresponding to R ^a18 , R ^a19 , R ^a20 , and R ^a24 in formulas (a3-1) to (a3-4) are replaced with hydrogen atoms are preferred.

When resin (A) contains structural unit (a3), the total content of the structural units in resin (A) is 1 mol% or more, preferably 3 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more. Also, it is 70 mol% or less, preferably 65 mol% or less, and more preferably 60 mol% or less. Specifically, it is 1 to 70 mol%, preferably 3 to 65 mol%, and more preferably 5 to 60 mol%.

The content of the structural unit (a3-1), the structural unit (a3-2), the structural unit (a3-3) or the structural unit (a3-4) is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more, based on the total structural units of the resin (A). Also, it is preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less. Specifically, it is preferably 1 to 60 mol%, more preferably 3 to 55 mol%, and even more preferably 5 to 50 mol%.

<Structural unit (a4)>
Examples of the structural unit (a4) include the following structural units.

[In formula (a4),
^R41 represents a hydrogen atom or a methyl group.
R ⁴² represents a saturated hydrocarbon group having 1 to 24 carbon atoms and containing a fluorine atom, and --CH ₂ -- contained in the saturated hydrocarbon group may be replaced by --O-- or --CO--.]
Examples of the saturated hydrocarbon group represented by R ⁴² include chain hydrocarbon groups, monocyclic or polycyclic alicyclic hydrocarbon groups, and groups formed by combining these groups.

Examples of chain hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl groups. Examples of monocyclic or polycyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups; decahydronaphthyl, adamantyl, and norbornyl groups; and polycyclic alicyclic hydrocarbon groups such as the following groups (* indicates a bonding site):

Examples of combined groups include groups that combine one or more alkyl groups or one or more alkanediyl groups with one or more alicyclic hydrocarbon groups, such as -alkanediyl group-alicyclic hydrocarbon group, -alicyclic hydrocarbon group-alkyl group, -alkanediyl group-alicyclic hydrocarbon group-alkyl group, etc.

The structural unit (a4) is preferably a structural unit having a fluorine atom, and examples of such structural units include at least one structural unit selected from the group consisting of formula (a4-0), formula (a4-1), formula (a4-2), formula (a4-3) and formula (a4-4).

[In formula (a4-0),
^R5 represents a hydrogen atom or a methyl group.
L ^4a represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms.

L ^3a represents a perfluoroalkanediyl group having 1 to 8 carbon atoms or a perfluorocycloalkanediyl group having 3 to 12 carbon atoms.
^R6 represents a hydrogen atom or a fluorine atom.
Examples of the divalent aliphatic saturated hydrocarbon group for L ^4a include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, and a butane-1,4-diyl group, and branched alkanediyl groups such as an ethane-1,1-diyl group, a propane-1,2-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, and a 2-methylpropane-1,2-diyl group.

Examples of the perfluoroalkanediyl group in L ^3a include a difluoromethylene group, a perfluoroethylene group, a perfluoropropane-1,1-diyl group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group, a perfluoropropane-2,2-diyl group, a perfluorobutane-1,4-diyl group, a perfluorobutane-2,2-diyl group, a perfluorobutane-1,2-diyl group, a perfluoropentane-1,5-diyl group, a perfluoropentane-2,2-diyl group, a perfluoropentane- Examples of the perfluorohexane-3,3-diyl group include perfluorohexane-1,6-diyl group, perfluorohexane-2,2-diyl group, perfluorohexane-3,3-diyl group, perfluoroheptane-1,7-diyl group, perfluoroheptane-2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane-2,2-diyl group, perfluorooctane-3,3-diyl group, and perfluorooctane-4,4-diyl group.

Examples of the perfluorocycloalkanediyl group in ^L3a include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, and a perfluoroadamantanediyl group.

L ^4a is preferably a single bond, a methylene group or an ethylene group, and more preferably a single bond or a methylene group.
L ^3a is preferably a perfluoroalkanediyl group having 1 to 6 carbon atoms, and more preferably a perfluoroalkanediyl group having 1 to 3 carbon atoms.

Examples of the structural unit (a4-0) include the structural units shown below and structural units in which the methyl group corresponding to R ⁵ in the structural unit (a4-0) shown below has been replaced with a hydrogen atom.

[In formula (a4-1),
R ^a41 represents a hydrogen atom or a methyl group.
R ^a42 represents a saturated hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and --CH ₂ -- contained in the saturated hydrocarbon group may be replaced by --O-- or --CO--.

A ^a41 represents an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a group represented by formula (a-g1), with the proviso that at least one of A ^a41 and R ^a42 has a halogen atom (preferably a fluorine atom) as a substituent.

[In formula (a-g1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent a divalent saturated hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.

A ^a43 represents a single bond or a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
X ^a41 and X ^a42 each independently represent -O-, -CO-, -CO-O- or -O-CO-.

However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less.
* indicates a binding site, and the * on the right side is the binding site with -O-CO-R ^a42 .]
Examples of the saturated hydrocarbon group for R ^a42 include chain saturated hydrocarbon groups, monocyclic or polycyclic alicyclic saturated hydrocarbon groups, and groups formed by combining these groups.

Examples of chain saturated hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl groups.

Examples of monocyclic or polycyclic alicyclic saturated hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl; and polycyclic alicyclic saturated hydrocarbon groups such as decahydronaphthyl, adamantyl, and norbornyl groups, as well as the following groups (* indicates a bonding site):

Examples of combined groups include groups that combine one or more alkyl groups or one or more alkanediyl groups with one or more alicyclic saturated hydrocarbon groups, such as -alkanediyl group-alicyclic saturated hydrocarbon group, -alicyclic saturated hydrocarbon group-alkyl group, -alkanediyl group-alicyclic saturated hydrocarbon group-alkyl group, etc.

Examples of the substituent that R ^a42 may have include at least one selected from a halogen atom and a group represented by formula (a-g3). Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.

[In formula (a-g3),
^Xa43 represents an oxygen atom, a carbonyl group, *-O-CO- or *-CO-O-.
A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom. * represents the bonding site with R ^a42 .]
However, in R ^a42 -X ^a43 -A ^a45 , when R ^a42 does not have a halogen atom, A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms and at least one halogen atom.

Examples of the aliphatic hydrocarbon group for A ^a45 include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, a dodecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group; monocyclic alicyclic hydrocarbon groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group; and polycyclic alicyclic hydrocarbon groups such as a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* represents a bonding site).

Examples of combined groups include groups that combine one or more alkyl groups or one or more alkanediyl groups with one or more alicyclic hydrocarbon groups, such as -alkanediyl group-alicyclic hydrocarbon group, -alicyclic hydrocarbon group-alkyl group, -alkanediyl group-alicyclic hydrocarbon group-alkyl group, etc.

R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, and more preferably an aliphatic hydrocarbon group having an alkyl group having a halogen atom and/or a group represented by formula (a-g3).

When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, it is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, still more preferably a perfluoroalkyl group having 1 to 6 carbon atoms, and particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. Examples of perfluoroalkyl groups include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Examples of perfluorocycloalkyl groups include a perfluorocyclohexyl group.

When R ^a42 is an aliphatic hydrocarbon group having a group represented by formula (a-g3), the total number of carbon atoms in R ^a42 , including the number of carbon atoms contained in the group represented by formula (a-g3), is preferably 15 or less, and more preferably 12 or less. When R a42 has a group represented by formula (a-g3) as a substituent, the number thereof is preferably 1.

When R ^a42 is an aliphatic hydrocarbon group having a group represented by formula (a-g3), R ^a42 is more preferably a group represented by formula (a-g2).

[In formula (a-g2),
A ^a46 represents a divalent aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.

X ^a44 represents **-O-CO- or **-CO-O- (** represents the bonding site with A ^a46 ).
A ^a47 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.

However, the total number of carbon atoms of A ^a46 , A ^a47 and X ^a44 is 18 or less, and at least one of A ^a46 and A ^a47 has at least one halogen atom.
* indicates the bonding site with the carbonyl group.
The aliphatic hydrocarbon group of ^Aa46 preferably has 1 to 6 carbon atoms, and more preferably has 1 to 3 carbon atoms.

The aliphatic hydrocarbon group of A ^a47 preferably has 4 to 15 carbon atoms, more preferably 5 to 12 carbon atoms, and A ^a47 is further preferably a cyclohexyl group or an adamantyl group.
A preferred structure of the group represented by formula (a-g2) is the following structure (* indicates the bonding site with the carbonyl group).

Examples of the alkanediyl group in A ^a41 include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group; and branched alkanediyl groups such as a propane-1,2-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a 1-methylbutane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group.

Examples of the substituent in the alkanediyl group of A ^a41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
A ^a41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and even more preferably an ethylene group.

Examples of the divalent saturated hydrocarbon group represented by A ^a42 , A ^a43 and A ^a44 in the group represented by formula (a-g1) include a linear or branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic hydrocarbon group, and a group formed by combining an alkanediyl group and a divalent alicyclic hydrocarbon group, etc. Specific examples include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a 1-methylpropane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, etc.

Examples of the substituent of the divalent saturated hydrocarbon group represented by A ^a42 , A ^a43 and A ^a44 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
It is preferred that s is 0.

In the group represented by formula (a-g1), examples of the group in which X ^a42 is -O-, -CO-, -CO-O- or -O-CO- include the following groups. In the following examples, * and ** each represent a bonding site, and ** is the bonding site with -O-CO-R ^a42 .

Examples of the structural unit represented by formula (a4-1) include the structural units shown below and structural units in which a methyl group corresponding to R ^a41 in the structural unit represented by formula (a4-1) in the following structural units is replaced with a hydrogen atom.

As the structural unit represented by formula (a4-1), a structural unit represented by formula (a4-2) is preferred.

[In formula (a4-2),
R ^f5 represents a hydrogen atom or a methyl group.
L ⁴⁴ represents an alkanediyl group having 1 to 6 carbon atoms, and --CH ₂ -- contained in the alkanediyl group may be replaced by --O-- or --CO--.

R ^f6 represents a saturated hydrocarbon group having 1 to 20 carbon atoms and containing a fluorine atom.
However, the upper limit of the total number of carbon atoms of L ⁴⁴ and R ^f6 is 21.
Examples of the alkanediyl group having 1 to 6 carbon atoms for L ⁴⁴ include the same groups as those exemplified as the alkanediyl group for A ^a41 .

Examples of the saturated hydrocarbon group of R ^f6 include the same groups as those exemplified for R ^a42 .
As the alkanediyl group having 1 to 6 carbon atoms for L ⁴⁴ , an alkanediyl group having 2 to 4 carbon atoms is preferable, and an ethylene group is more preferable.

Examples of the structural unit represented by formula (a4-2) include structural units represented by formulas (a4-1-1) to (a4-1-11). The structural unit represented by formula (a4-2) also includes a structural unit in which a methyl group corresponding to ^Rf5 in the structural unit (a4-2) is replaced with a hydrogen atom.

Examples of the structural unit (a4) include the structural unit represented by formula (a4-3).

[In formula (a4-3),
R ^f7 represents a hydrogen atom or a methyl group.
^L5 represents an alkanediyl group having 1 to 6 carbon atoms.

A ^f13 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom.
X ^f12 represents *--O--CO-- or *--CO--O-- (* represents the bonding site with A ^f13 ).

A ^f14 represents a saturated hydrocarbon group having 1 to 17 carbon atoms which may have a fluorine atom.
However, at least one of A ^f13 and A ^f14 has a fluorine atom, and the upper limit of the total number of carbon atoms of L ⁵ , A ^f13 and A ^f14 is 20.]
Examples of the alkanediyl group for ^L5 include the same groups as those exemplified as the alkanediyl group for the divalent saturated hydrocarbon group for ^Aa41 .

The divalent saturated hydrocarbon group for A ^f13 which may have a fluorine atom is preferably a divalent chain saturated hydrocarbon group which may have a fluorine atom and a divalent alicyclic saturated hydrocarbon group which may have a fluorine atom, and more preferably a perfluoroalkanediyl group.

Examples of divalent chain saturated hydrocarbon groups which may have fluorine atoms include alkanediyl groups such as methylene, ethylene, propanediyl, butanediyl and pentanediyl groups; and perfluoroalkanediyl groups such as difluoromethylene, perfluoroethylene, perfluoropropanediyl, perfluorobutanediyl and perfluoropentanediyl groups.

The divalent alicyclic saturated hydrocarbon group which may have a fluorine atom may be either monocyclic or polycyclic. Examples of monocyclic groups include a cyclohexanediyl group and a perfluorocyclohexanediyl group. Examples of polycyclic groups include an adamantanediyl group, a norbornanediyl group, and a perfluoroadamantanediyl group.

Examples of the saturated hydrocarbon group and the saturated hydrocarbon group which may have a fluorine atom of A ^f14 include the same groups as those exemplified for R ^a42 . Among them, a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a propyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a butyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, Preferred are fluorinated alkyl groups such as a hexyl group, a perfluorohexyl group, a heptyl group, a perfluoroheptyl group, an octyl group, and a perfluorooctyl group, a cyclopropylmethyl group, a cyclopropyl group, a cyclobutylmethyl group, a cyclopentyl group, a cyclohexyl group, a perfluorocyclohexyl group, an adamantyl group, an adamantylmethyl group, an adamantyldimethyl group, a norbornyl group, a norbornylmethyl group, a perfluoroadamantyl group, and a perfluoroadamantylmethyl group.

In formula (a4-3), ^L5 is preferably an ethylene group.
The divalent saturated hydrocarbon group for A ^f13 is preferably a group containing a divalent chain saturated hydrocarbon group having 1 to 6 carbon atoms and a divalent alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, and more preferably a divalent chain saturated hydrocarbon group having 2 to 3 carbon atoms.

The saturated hydrocarbon group of A ^f14 is preferably a group containing a chain saturated hydrocarbon group having 3 to 12 carbon atoms and an alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, and more preferably a group containing a chain saturated hydrocarbon group having 3 to 10 carbon atoms and an alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms. Of these, A ^f14 is preferably a group containing an alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, and more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, or an adamantyl group.

Examples of the structural unit represented by formula (a4-3) include structural units represented by formulas (a4-1'-1) to (a4-1'-11). The structural unit represented by formula (a4-3) also includes a structural unit in which the methyl group corresponding to ^Rf7 in the structural unit (a4-3) is replaced with a hydrogen atom.

The structural unit (a4) may also be a structural unit represented by formula (a4-4).

[In formula (a4-4),
R ^f21 represents a hydrogen atom or a methyl group.
A ^f21 represents -(CH ₂ ) _j1 -, -(CH ₂ ) _j2 -O-(CH ₂ ) _j3 - or -(CH ₂ ) _j4 -CO-O-(CH ₂ ) _j5 -.

j1 to j5 each independently represent an integer of 1 to 6.
R ^f22 represents a saturated hydrocarbon group having 1 to 10 carbon atoms and a fluorine atom.]
Examples of the saturated hydrocarbon group of R ^f22 include the same as the saturated hydrocarbon group represented by R ^a42 . R ^f22 is preferably an alkyl group having 1 to 10 carbon atoms and containing a fluorine atom, or an alicyclic hydrocarbon group having 1 to 10 carbon atoms and containing a fluorine atom, more preferably an alkyl group having 1 to 10 carbon atoms and containing a fluorine atom, and even more preferably an alkyl group having 1 to 6 carbon atoms and containing a fluorine atom.

In formula (a4-4), A ^f21 is preferably —(CH ₂ ) _j1 —, more preferably an ethylene group or a methylene group, and even more preferably a methylene group.
Examples of the structural unit represented by formula (a4-4) include the following structural units and structural units represented by the following formula in which a methyl group corresponding to R ^f21 in the structural unit (a4-4) is replaced with a hydrogen atom.

When resin (A) contains structural unit (a4), its content is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and even more preferably 3 to 10 mol %, based on the total structural units of resin (A).

<Structural unit (a5)>
The non-leaving hydrocarbon group contained in the structural unit (a5) may be a group having a linear, branched or cyclic hydrocarbon group. Among these, the structural unit (a5) is preferably a group having an alicyclic hydrocarbon group.

An example of the structural unit (a5) is a structural unit represented by formula (a5-1).

[In formula (a5-1),
R ⁵¹ represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms.

L ⁵⁵ represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and --CH ₂ -- contained in the saturated hydrocarbon group may be replaced with --O-- or --CO--.]
The alicyclic hydrocarbon group in ^R52 may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the polycyclic alicyclic hydrocarbon group include an adamantyl group, a norbornyl group, and the like.

Examples of aliphatic hydrocarbon groups having 1 to 8 carbon atoms include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, and 2-ethylhexyl.

An example of the alicyclic hydrocarbon group having a substituent is a 3-methyladamantyl group.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and more preferably an adamantyl group, a norbornyl group, or a cyclohexyl group.

The divalent saturated hydrocarbon group for L ⁵⁵ includes a divalent chain saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, and is preferably a divalent chain saturated hydrocarbon group.
Examples of the divalent chain saturated hydrocarbon group include alkanediyl groups such as a methylene group, an ethylene group, a propanediyl group, a butanediyl group, and a pentanediyl group.

The divalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. Examples of monocyclic alicyclic saturated hydrocarbon groups include cycloalkanediyl groups such as cyclopentanediyl and cyclohexanediyl groups. Examples of polycyclic divalent alicyclic saturated hydrocarbon groups include adamantanediyl and norbornanediyl groups.

Examples of the divalent saturated hydrocarbon group represented by L ⁵⁵ in which --CH ₂ -- is replaced by --O-- or --CO-- include groups represented by formulae (L1-1) to (L1-4). In the following formulae, * and ** each represent a bonding site, and * represents a bonding site with an oxygen atom.

[In formula (L1-1),
X ^x1 represents *-O-CO- or *-CO-O- (* represents the bonding site with L ^x1 ).

L ^x1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
L ^x2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
However, the total number of carbon atoms in L ^x1 and L ^x2 is 16 or less.
[In formula (L1-2),
^Lx3 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms.

L ^x4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
However, the total number of carbon atoms in L ^x3 and L ^x4 is 17 or less.
[In formula (L1-3),
L ^x5 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.

L ^x6 and L ^x7 each independently represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
However, the total number of carbon atoms of L ^x5 , L ^x6 and L ^x7 is 15 or less.
[In formula (L1-4),
L ^x8 and L ^x9 each represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.

W ^x1 represents a divalent alicyclic saturated hydrocarbon group having 3 to 15 carbon atoms.
However, the total number of carbon atoms of L ^x8 , L ^x9 and W ^x1 is 15 or less.
L ^x1 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.

L ^x2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond.
L ^x3 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.

L ^x4 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x5 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.

L ^x6 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x7 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.

L ^x8 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group.
L ^x9 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group.

W ^x1 is preferably a divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, more preferably a cyclohexanediyl group or an adamantanediyl group.
Examples of the group represented by formula (L1-1) include the divalent groups shown below.

Examples of the group represented by formula (L1-2) include the divalent groups shown below.

Examples of the group represented by formula (L1-3) include the divalent groups shown below.

Examples of the group represented by formula (L1-4) include the divalent groups shown below.

L ⁵⁵ is preferably a single bond or a group represented by the formula (L1-1).
Examples of the structural unit (a5-1) include the structural units shown below and structural units in which a methyl group corresponding to R ⁵¹ in the structural unit (a5-1) shown below has been replaced with a hydrogen atom.

When resin (A) contains structural unit (a5), its content is preferably 1 to 30 mol %, more preferably 2 to 20 mol %, and even more preferably 3 to 15 mol %, based on the total structural units of resin (A).

<Structural unit (a6)>
The structural unit (a6) is a structural unit having an —SO ₂ — group, and preferably has the —SO ₂ — group in a side chain.

The structural unit having an —SO ₂ — group may have a linear structure having an —SO ₂ — group, may have a branched structure having an —SO ₂ — group, or may have a cyclic structure (monocyclic or polycyclic structure) having an —SO ₂ — group. A structural unit having a cyclic structure having an —SO ₂ — group is preferred, and a structural unit having a cyclic structure containing —SO ₂ —O— (sultone ring) is more preferred.

Examples of the sultone ring include rings represented by the following formulae (T ¹ -1), (T ¹ -2), (T ¹ -3) and (T ¹ -4). The binding site can be any position. The sultone ring may be monocyclic, but is preferably polycyclic. The polycyclic sultone ring means a bridged ring containing -SO ₂ -O- as an atomic group constituting the ring, and examples of the polycyclic sultone ring include rings represented by the formulae (T ¹ -1) and (T ¹ -2). The sultone ring may further contain a heteroatom as an atomic group constituting the ring in addition to -SO ₂ -O-, as in the ring represented by the formula (T ¹ -2). Examples of the heteroatom include an oxygen atom, a sulfur atom or a nitrogen atom, and preferably an oxygen atom.

The sultone ring may have a substituent, and examples of the substituent include an alkyl group having 1 to 12 carbon atoms which may have a halogen atom or a hydroxyl group, a halogen atom, a hydroxyl group, a cyano group, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an alkoxycarbonyl group having 2 to 12 carbon atoms, and an alkylcarbonyl group having 2 to 4 carbon atoms.

Examples of halogen atoms include fluorine, chlorine, bromine and iodine atoms.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, and a decyl group. Of these, an alkyl group having 1 to 6 carbon atoms is preferred, and a methyl group is more preferred.

Examples of alkyl groups having a halogen atom include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, a perfluorohexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group, and preferably a trifluoromethyl group.

Examples of the alkyl group having a hydroxy group include a hydroxymethyl group and a 2-hydroxyethyl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, and a dodecyloxy group.

Aryl groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumyl, mesityl, biphenyl, phenanthryl, 2,6-diethylphenyl, and 2-methyl-6-ethylphenyl.

Aralkyl groups include benzyl, phenethyl, phenylpropyl, naphthylmethyl and naphthylethyl groups.
Examples of the alkoxycarbonyl group include groups in which an alkoxy group, such as a methoxycarbonyl group or an ethoxycarbonyl group, is bonded to a carbonyl group, and preferably, an alkoxycarbonyl group having 6 or less carbon atoms is used, and more preferably, a methoxycarbonyl group is used.

Alkylcarbonyl groups include acetyl, propionyl and butyryl groups.
From the viewpoint of ease of production of the monomer from which the structural unit (a6) is derived, a sultone ring having no substituent is preferred.

The sultone ring is preferably a ring represented by the following formula (T1'):

[In the formula (T1'),
^X11 represents an oxygen atom, a sulfur atom or a methylene group.
R ⁴¹ represents an alkyl group having 1 to 12 carbon atoms which may have a halogen atom or a hydroxyl group, a halogen atom, a hydroxyl group, a cyano group, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a glycidyloxy group, an alkoxycarbonyl group having 2 to 12 carbon atoms, or an alkylcarbonyl group having 2 to 4 carbon atoms.

ma represents an integer of 0 to 9. When ma is 2 or more, multiple R ⁴¹ may be the same or different.
The binding site is at any position.]
^X11 is preferably an oxygen atom or a methylene group, and more preferably a methylene group.

Examples of R ⁴¹ include the same substituents as those of the sultone ring described above, and an alkyl group having 1 to 12 carbon atoms which may have a halogen atom or a hydroxyl group is preferable.
ma is preferably 0 or 1, and more preferably 0.

Examples of the ring represented by formula (T1') include the following rings. The binding site may be any position. Of these, the binding site is preferably the 1st or 3rd position.

It is preferable that the structural unit having an —SO ₂ — group further has a group derived from a polymerizable group, such as a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group, an acryloylamino group, a methacryloylamino group, an acryloylthio group, or a methacryloylthio group.

Among these, the monomer from which the structural unit (a6) is derived is preferably a monomer having an ethylenically unsaturated bond, and more preferably a (meth)acrylic monomer.
The structural unit (a6) is preferably a structural unit represented by the formula (a6-0).

In formula (a6-0), R ^x represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom, or a halogen atom.
A ^xx represents an oxygen atom, —N(R ^c )— or a sulfur atom.

A ^x represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and --CH ₂ -- contained in the saturated hydrocarbon group may be replaced by --O--, --CO-- or --N(R ^d )--.

X ¹¹ , R ⁴¹ and ma have the same meanings as above.
R ^c and R ^d each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
The halogen atom of R ^x includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the alkyl group of R ^x include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. An alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group or an ethyl group is more preferable.

Examples of the alkyl group having a halogen atom for R ^x include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, a perfluorohexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.

R ^x is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group.
Examples of the divalent saturated hydrocarbon group for A ^x include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and two or more of these groups may be combined.

Specific examples include methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, heptadecane-1,17-diyl, ethane-1,1-diyl, propane-1,1-diyl, and propane-2,2-diyl groups. linear alkanediyl groups; branched alkanediyl groups such as butane-1,3-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl, pentane-1,4-diyl, and 2-methylbutane-1,4-diyl groups; monocyclic divalent alicyclic saturated hydrocarbon groups such as cycloalkanediyl groups such as cyclobutane-1,3-diyl, cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, and cyclooctane-1,5-diyl groups; and polycyclic divalent alicyclic saturated hydrocarbon groups such as norbornane-1,4-diyl, norbornane-2,5-diyl, adamantane-1,5-diyl, and adamantane-2,6-diyl groups.

The bonding position of ^Ax to the sultone ring may be any position, but is preferably the 1-position.
Examples of the structural unit (a6-0) include the following structural units.

Among these, structural units represented by formulae (a6-1), (a6-2), (a6-6), (a6-7), (a6-8) and (a6-12) are preferred, and structural units represented by formulae (a6-1), (a6-2), (a6-7) and (a6-8) are more preferred.

When resin (A) contains structural unit (a6), its content is preferably 1 to 50 mol %, more preferably 2 to 40 mol %, and even more preferably 3 to 30 mol %, based on the total structural units of resin (A).

<Structural Unit (II)>
Resin (A) may further contain a structural unit that decomposes upon exposure to generate an acid (hereinafter, sometimes referred to as "structural unit (II)"). Specific examples of the structural unit (II) include the structural units described in JP-A-2016-79235, and are preferably a structural unit having a sulfonate group or carboxylate group and an organic cation in a side chain, or a structural unit having a sulfonio group and an organic anion in a side chain.

The structural unit having a sulfonate group or a carboxylate group and an organic cation in the side chain is preferably a structural unit represented by formula (II-2-A').

[In the formula (II-2-A′),
^XIII3 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, in which -CH ₂ - contained in the saturated hydrocarbon group may be replaced by -O-, -S- or -CO-, and a hydrogen atom contained in the saturated hydrocarbon group may be replaced by a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, or a hydroxy group.

A ^x1 represents an alkanediyl group having 1 to 8 carbon atoms, and a hydrogen atom contained in the alkanediyl group may be substituted by a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.

^RA- represents a sulfonate group or a carboxylate group.
R ^III3 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.

ZA ⁺ represents an organic cation.
Examples of the halogen atom represented by R ^III3 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom and which is represented by R ^III3 include the same as the alkyl group having 1 to 6 carbon atoms which may have a halogen atom and which is represented by R ^a8 .

Examples of the alkanediyl group having 1 to 8 carbon atoms represented by A ^x1 include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a pentane-2,4-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group.

Examples of the perfluoroalkyl group having 1 to 6 carbon atoms which may be substituted in ^X1 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluorohexyl group.

Examples of the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by ^XIII3 include linear or branched alkanediyl groups, and monocyclic or polycyclic divalent alicyclic saturated hydrocarbon groups, and combinations of these may also be used.

Specific examples include linear alkanediyl groups such as methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, and dodecane-1,12-diyl; butane-1,3-diyl, 2-methylpropane-1,3-diyl, and 2-methylpropane-1,4-diyl; branched alkanediyl groups such as cyclohexane-1,2-diyl, pentane-1,4-diyl, and 2-methylbutane-1,4-diyl; cycloalkanediyl groups such as cyclobutane-1,3-diyl, cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, and cyclooctane-1,5-diyl; and divalent polycyclic alicyclic saturated hydrocarbon groups such as norbornane-1,4-diyl, norbornane-2,5-diyl, adamantane-1,5-diyl, and adamantane-2,6-diyl.

Examples of saturated hydrocarbon groups in which -CH ₂ - is replaced by -O-, -S- or -CO- include divalent groups represented by formulae (X1) to (X53), where the number of carbon atoms before -CH ₂ - in the saturated hydrocarbon group is replaced by -O-, -S- or -CO- is 17 or less. In the following formulae, * and ** represent bonding sites, and * represents the bonding site with A ^x1 .

^X3 represents a divalent saturated hydrocarbon group having 1 to 16 carbon atoms.
^X4 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
^X5 represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.

^X6 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
^X7 represents a trivalent saturated hydrocarbon group having 1 to 14 carbon atoms.
^X8 represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.

ZA ⁺ in formula (II-2-A') is the same as the cation Z1 ⁺ in the salt represented by formula (B1).
The structural unit represented by formula (II-2-A') is preferably a structural unit represented by formula (II-2-A).

[In formula (II-2-A),
R ^III3 , X ^III3 and ZA ⁺ have the same meanings as above.
z2A represents an integer of 0 to 6.

R ^III2 and R ^III4 each independently represent a hydrogen atom, a fluorine atom, or a perfluoroalkyl group having 1 to 6 carbon atoms, and when z2A is 2 or greater, a plurality of R ^III2's and R ^III4 's may be the same or different.

Q ^a and Q ^b each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.]
Examples of the perfluoroalkyl group having 1 to 6 carbon atoms represented by R ^III2 , R ^III4 , Q ^a and Q ^b include the same perfluoroalkyl groups having 1 to 6 carbon atoms represented by Q ^b1 described above.

The structural unit represented by formula (II-2-A) is preferably a structural unit represented by formula (II-2-A-1).

[In formula (II-2-A-1),
R ^III2 , R ^III3 , R ^III4 , Q ^a , Q ^b and ZA ⁺ have the same meanings as above.

R ^III5 represents a saturated hydrocarbon group having 1 to 12 carbon atoms.
z2A1 represents an integer of 0 to 6.
X ^I2 represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms, -CH ₂ - contained in the saturated hydrocarbon group may be replaced by -O-, -S- or -CO-, and a hydrogen atom contained in the saturated hydrocarbon group may be replaced by a halogen atom or a hydroxyl group.]
Examples of the saturated hydrocarbon group having 1 to 12 carbon atoms represented by R ^III5 include linear or branched alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group.

Examples of the divalent saturated hydrocarbon group represented by X ^I2 include the same as the divalent saturated hydrocarbon group represented by X ^III3 .
The structural unit represented by formula (II-2-A-1) is more preferably a structural unit represented by formula (II-2-A-2).

[In formula (II-2-A-2),
R ^III3 , R ^III5 and ZA ⁺ have the same meanings as above.
m and nA each independently represent 1 or 2.
Examples of the structural unit represented by formula (II-2-A') include the following structural units, structural units in which the group corresponding to the methyl group of R ^III3 is replaced with a hydrogen atom, a halogen atom (e.g., a fluorine atom) or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom (e.g., a trifluoromethyl group, etc.), and structural units described in WO 2012/050015. ZA ⁺ represents an organic cation.

The structural unit having a sulfonio group and an organic anion in the side chain is preferably a structural unit represented by formula (II-1-1).

[In formula (II-1-1),
A ^II1 represents a single bond or a divalent linking group.
R ^II1 represents a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.

R ^II2 and R ^II3 each independently represent a hydrocarbon group having 1 to 18 carbon atoms, and R ^II2 and R ^II3 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

R ^II4 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
A ⁻ represents an organic anion.
Examples of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms represented by R ^II1 include a phenylene group and a naphthylene group.

Examples of the hydrocarbon group represented by R ^II2 and R ^II3 include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a combination thereof.
Examples of the alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, and groups formed by combining these groups include the same as those described above.

Examples of the halogen atom represented by ^RII4 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom and which is represented by R ^II4 include the same as the alkyl group having 1 to 6 carbon atoms which may have a halogen atom and which is represented by R ^a8 .

Examples of the divalent linking group represented by A ^II1 include a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, in which -CH ₂ - may be replaced by -O-, -S- or -CO-. Specific examples include the same as the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by X ^III3 .

Examples of the structural unit containing a cation in formula (II-1-1) include structural units represented by the following formulas and structural units in which a group corresponding to the methyl group in R ^II4 is replaced with a hydrogen atom, a halogen atom (e.g., a fluorine atom), or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom (e.g., a trifluoromethyl group, etc.).

Examples of the organic anion represented by ^A- include a sulfonate anion, a sulfonylimide anion, a sulfonylmethide anion, and a carboxylate anion. The organic anion represented ^by A- is preferably a sulfonate anion. The sulfonate anion is more preferably the anion ^AI- contained in the salt represented by the above formula (I). The sulfonylimide anion and the sulfonylmethide anion are more preferably the anion ^AI- contained in the salt represented by the above formula (I), and examples of the carboxylate anion include the same anions as those exemplified for the above compound (B).

Examples of the structural unit represented by formula (II-1-1) include the structural units represented below.

When the resin (A) contains the structural unit (II), the content of the structural unit (II) is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and even more preferably 3 to 10 mol %, based on the total structural units of the resin (A).

The resin (A1) is preferably a resin consisting of the structural unit (a1) or a resin consisting of the structural unit (a1) and the structural unit (s).
The structural unit (a1) is preferably at least one selected from the group consisting of the structural unit (a1-0), the structural unit (a1-0X), the structural unit (a1-1), and the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or a cyclopentyl group), and more preferably at least two selected from the group consisting of the structural unit (a1-0), the structural unit (a1-0X), the structural unit (a1-1), and the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or a cyclopentyl group).

The structural unit (s) is preferably at least one selected from the group consisting of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably a structural unit represented by formula (a2-1) or a structural unit represented by formula (a2-A). The structural unit (a3) is preferably at least one selected from the group consisting of a structural unit represented by formula (a3-1), a structural unit represented by formula (a3-2), and a structural unit represented by formula (a3-4).

Each structural unit constituting resin (A) may be used alone or in combination of two or more types, and can be produced by a known polymerization method (e.g., radical polymerization method) using monomers that lead to these structural units. The content of each structural unit in resin (A) can be adjusted by the amount of monomer used in polymerization.

The weight average molecular weight of resin (A) is preferably 2,000 or more (more preferably 2,500 or more, and even more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less, and even more preferably 15,000 or less), but may contain oligomers with a weight average molecular weight of less than 2,000 or more.

In this specification, the weight average molecular weight is a value determined by gel permeation chromatography. Gel permeation chromatography can be measured under the analytical conditions described in the Examples.

<Resins other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A).
Examples of resins other than resin (A) include a resin having the same structural units as resin (A) except that resin (A) does not contain the structural unit (a1) (hereinafter, may be referred to as resin (AX)), and a resin containing structural unit (a4) and/or structural unit (a5) (hereinafter, may be referred to as resin (X)).

Examples of resin (AX) include resins containing the structural unit (a2), and preferably contain the structural unit (a2-A). In resin (AX), the content of structural unit (a2-A) is preferably 5 to 80 mol %, more preferably 10 to 70 mol %, based on the total of all structural units in resin (AX).

Examples of structural units that the resin (X) may further have include the structural unit (a2), the structural unit (a3), and structural units derived from other known monomers. Of these, the resin (X) is preferably a resin consisting only of the structural unit (a4) and/or the structural unit (a5).

When the resin (X) contains the structural unit (a4), the content of the structural unit (a4) in the resin (X) is 20 mol% or more, preferably 30 mol% or more, more preferably 40 mol% or more, and even more preferably 45 mol% or more, based on the total of all structural units in the resin (X). Also, 100 mol% or less is preferable, 80 mol% or less is preferable, 70 mol% or less is more preferable, 60 mol% or less is more preferable, and 55 mol% or less is even more preferable. Specifically, 20 to 100 mol% is preferable, 20 to 80 mol% is preferable, 30 to 70 mol% is more preferable, 40 to 60 mol% is even more preferable, and 45 to 55 mol% is even more preferable. When the resin (X) contains the structural unit (a5), the content of the structural unit (a5) is 20 mol% or more, preferably 30 mol% or more, more preferably 40 mol% or more, and even more preferably 45 mol% or more, based on the total of all structural units in the resin (X). Also, 100 mol% or less can be mentioned, 80 mol% or less is preferable, 70 mol% or less is more preferable, 60 mol% or less is even more preferable, and 55 mol% or less is even more preferable. Specifically, 20 to 100 mol% can be mentioned, 20 to 80 mol% is preferable, 30 to 70 mol% is more preferable, 40 to 60 mol% is even more preferable, and 45 to 55 mol% is even more preferable. Furthermore, when the resin (X) contains the structural unit (a4) and the structural unit (a5), the total content of the structural unit (a4) and the structural unit (a5) can be 40 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 mol% or more, based on the total of all structural units of the resin (X). Also, 100 mol% or less can be mentioned. Specifically, 40 to 100 mol% can be mentioned, 60 to 100 mol% is preferable, 70 to 100 mol% is more preferable, and 80 to 100 mol% is even more preferable. Furthermore, the ratio of structural unit (a4):structural unit (a5) is 0:100 to 100:0, preferably 10:90 to 90:10, and more preferably 30:70 to 70:30 or 40:60 to 60:40.

The structural units constituting resin (AX) and resin (X) may be used alone or in combination of two or more types, and can be produced by a known polymerization method (e.g., radical polymerization method) using monomers that derive these structural units. The content of each structural unit in resin (AX) and resin (X) can be adjusted by the amount of monomer used in polymerization.

The weight average molecular weight of the resin (AX) may be the same as that of the resin (A).
The weight average molecular weight of resin (X) is preferably 6,000 or more (more preferably 7,000 or more) and 80,000 or less (more preferably 60,000 or less), but may contain oligomers having a weight average molecular weight of less than 6,000. The method for measuring the weight average molecular weight of resin (X) is the same as that for resin (A).

When the resist composition of the present invention contains resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, even more preferably 1 to 40 parts by mass, even more preferably 1 to 30 parts by mass, and even more preferably 1 to 8 parts by mass, relative to 100 parts by mass of resin (A) and/or resin (AX).

When the resist composition contains resin (A), the content of resin (A) is preferably 80% by mass or more and 99% by mass or less, and more preferably 90% by mass or more and 99% by mass or less, based on the solid content of the resist composition. When a resin other than resin (A) is contained, the total content of resin (A) and/or resin other than resin (A) is preferably 80% by mass or more and 99% by mass or less, and more preferably 90% by mass or more and 99% by mass or less, based on the solid content of the resist composition. The solid content of the resist composition and the resin content therein can be measured by known analytical means such as liquid chromatography or gas chromatography.

<Solvent (E)>
The content of the solvent (E) in the resist composition is usually from 90% by mass to 99.9% by mass, preferably from 92% by mass to 99% by mass, and more preferably from 94% by mass to 99% by mass. The content of the solvent (E) can be measured by a known analytical method such as liquid chromatography or gas chromatography.

Examples of the solvent (E) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate, and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; esters such as ethyl lactate, butyl acetate, amyl acetate, and ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone, and cyclohexanone; cyclic esters such as γ-butyrolactone; and the like. One type of solvent (E) may be used alone, or two or more types may be used.

<Quencher (C)>
Examples of the quencher (C) include salts that generate an acid having a weaker acidity than the acid generated from the basic nitrogen-containing organic compound and the acid generator (salt (I) or compound (B)). When the resist composition contains the quencher (C), the content of the quencher (C) is preferably about 0.01 to 15 mass %, more preferably about 0.01 to 10 mass %, even more preferably about 0.1 to 8 mass %, and even more preferably about 0.1 to 7 mass %, based on the solids content of the resist composition.

Basic nitrogen-containing organic compounds include amines and ammonium salts. Amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines, and tertiary amines.

Amines include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N,N-dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributaryamine, ethylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldi Decylamine, dicyclohexylmethylamine, tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, 2,2'-methylenebisaniline, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 1,2-di(2-pyridyl)amine, di(4-pyridyl)ethane, 1,2-di(4-pyridyl)ethane, 1,2-di(2-pyridyl)ethene, 1,2-di(4-pyridyl)ethene, 1,3-di(4-pyridyl)propane, 1,2-di(4-pyridyloxy)ethane, di(2-pyridyl)ketone, 4,4'-dipyridyl sulfide, 4,4'-dipyridyl disulfide, 2,2'-dipyridylamine, 2,2'-dipicolylamine, bipyridine, etc., preferably diisopropylaniline, more preferably 2,6-diisopropylaniline.

Examples of ammonium salts include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-(trifluoromethyl)phenyltrimethylammonium hydroxide, tetra-n-butylammonium salicylate, and choline.

The acidity of a salt that generates an acid weaker than the acid generated from the acid generator is indicated by the acid dissociation constant (pKa). A salt that generates an acid weaker than the acid generated from the acid generator is usually a salt whose acid dissociation constant of the acid generated from the salt is -3<pKa, preferably -1<pKa<7, and more preferably 0<pKa<5.

Examples of salts that generate an acid with a weaker acidity than the acid generated from the acid generator include salts represented by the following formula, salts represented by formula (D) described in JP 2015-147926 A (hereinafter sometimes referred to as "weak acid inner salt (D)"), and salts described in JP 2012-229206 A, JP 2012-6908 A, JP 2012-72109 A, JP 2011-39502 A, and JP 2011-191745 A. The salt that generates an acid with a weaker acidity than the acid generated from the acid generator is preferably a salt (salt having a carboxylate anion) that generates a carboxylic acid with a weaker acidity than the acid generated from the acid generator, more preferably a weak acid inner salt (D), and even more preferably a diphenyliodonium salt containing a phenyl group substituted with a carboxylate anion among the weak acid inner salts (D).

The weak acid inner salt (D) is preferably a diphenyliodonium salt having an iodonium cation to which two phenyl groups are bonded and a carboxylate anion substituted for at least one of the two phenyl groups bonded to the iodonium cation, and specifically includes salts represented by the following formula:

[In the formula (D),
R ^D1 and R ^D2 each independently represent a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 7 carbon atoms, an acyloxy group having 2 to 7 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, a nitro group, or a halogen atom.

m' and n' each independently represent an integer of 0 to 4, and when m' is 2 or greater, multiple R ^D1s may be the same or different, and when n' is 2 or greater, multiple R ^D2s may be the same or different.
Examples of the hydrocarbon group for R ^D1 and R ^D2 include a chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a combination of these.

Examples of chain hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, and nonyl.

Alicyclic hydrocarbon groups may be either monocyclic or polycyclic, and may be either saturated or unsaturated. Examples include cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclononyl, and cyclododecyl, norbornyl, and adamantyl.

Examples of aromatic hydrocarbon groups include aryl groups such as phenyl, 1-naphthyl, 2-naphthyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-propylphenyl, 4-isopropylphenyl, 4-butylphenyl, 4-t-butylphenyl, 4-hexylphenyl, 4-cyclohexylphenyl, anthryl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl, phenanthryl, 2,6-diethylphenyl, and 2-methyl-6-ethylphenyl.

Groups that combine these include alkyl-cycloalkyl groups, cycloalkyl-alkyl groups, and aralkyl groups (e.g., phenylmethyl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenyl-1-propyl group, 1-phenyl-2-propyl group, 2-phenyl-2-propyl group, 3-phenyl-1-propyl group, 4-phenyl-1-butyl group, 5-phenyl-1-pentyl group, and 6-phenyl-1-hexyl group).

Examples of the alkoxy group include a methoxy group and an ethoxy group.
Examples of the acyl group include an acetyl group, a propanoyl group, a benzoyl group, and a cyclohexanecarbonyl group.

Examples of the acyloxy group include the above-mentioned acyl groups to which an oxy group (—O—) is bonded.
Examples of the alkoxycarbonyl group include the above alkoxy groups bonded to a carbonyl group (--CO--).

Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.
R ^D1 and R ^D2 are each preferably an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a nitro group, or a halogen atom.

Each of m' and n' is preferably an integer of 0 to 2, and more preferably 0. When m' is 2 or more, multiple R ^D1s may be the same or different, and when n' is 2 or more, multiple R ^D2s may be the same or different.

More specifically, the following salts can be mentioned:

<Other Ingredients>
The resist composition of the present invention may contain components other than the above-mentioned components (hereinafter, sometimes referred to as "other components (F)") as necessary. There are no particular limitations on the other components (F), and additives known in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, etc., can be used.

Preparation of Resist Composition
The resist composition of the present invention can be prepared by mixing the salt (I), and, if necessary, the compound (B), the resin (A), a resin other than the resin (A), the solvent (E), the quencher (C), and other components (F). The order of mixing is arbitrary and is not particularly limited. The temperature during mixing can be selected from 10 to 40° C. depending on the type of resin, the solubility of the resin in the solvent (E), and the like. The mixing time can be selected from 0.5 hours to 24 hours depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing can be used.

After mixing the components, it is preferable to filter the mixture using a filter having a pore size of about 0.003 μm to 0.2 μm.
<Method for Producing Resist Pattern>
The method for producing a resist pattern of the present invention comprises the steps of:
(1) applying the resist composition of the present invention onto a substrate;
(2) A step of drying the applied resist composition to form a composition layer;
(3) exposing the composition layer to light;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.

The resist composition can be applied to a substrate using a commonly used device such as a spin coater. Examples of the substrate include inorganic substrates such as silicon wafers, and organic substrates having a resist film or the like formed on the surface. Before applying the resist composition, the substrate may be cleaned, and an anti-reflective film or the like may be formed on the substrate.

The applied resist composition is dried to remove the solvent and form a composition layer. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called pre-baking), or by using a vacuum device. The heating temperature is preferably 50 to 200° C., and the heating time is preferably 10 to 180 seconds. The pressure during drying under reduced pressure is preferably about 1 to 1.0×10 ⁵ Pa.

The obtained composition layer is usually exposed using an exposure machine. The exposure machine may be an immersion exposure machine. As the exposure light source, various types can be used, such as those that emit ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), and _F2 excimer laser (wavelength 157 nm), those that convert the wavelength of laser light from a solid laser light source (YAG or semiconductor laser, etc.) to emit harmonic laser light in the far ultraviolet or vacuum ultraviolet range, and those that irradiate electron beams or extreme ultraviolet light (EUV). In this specification, irradiation with these radiations may be collectively referred to as "exposure". During exposure, exposure is usually performed through a mask corresponding to the desired pattern. When the exposure light source is an electron beam, exposure may be performed by direct drawing without using a mask.

The composition layer after exposure is subjected to a heat treatment (so-called post-exposure bake) to promote the deprotection reaction of the acid labile groups. The heating temperature is usually about 50 to 200°C, preferably about 70 to 150°C. A chemical treatment (silylation) may be performed to adjust the hydrophilicity or hydrophobicity of the resin on the surface side of the heated composition. In addition, the steps of applying a resist composition, drying, exposing, and heating may be repeated on the composition layer after exposure before development.

The heated composition layer is usually developed using a developing device with a developer. Examples of the development method include the dip method, the paddle method, the spray method, and the dynamic dispense method. The development temperature is preferably, for example, 5 to 60°C, and the development time is preferably, for example, 5 to 300 seconds. By selecting the type of developer as follows, a positive resist pattern or a negative resist pattern can be produced.

When a positive resist pattern is produced from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be any of various alkaline aqueous solutions used in this field. Examples include aqueous solutions of tetramethylammonium hydroxide and (2-hydroxyethyl)trimethylammonium hydroxide (commonly known as choline). The alkaline developer may contain a surfactant.

After development, the resist pattern is preferably washed with ultrapure water, and then water remaining on the substrate and the pattern is removed.
When producing a negative resist pattern from the resist composition of the present invention, a developer containing an organic solvent (hereinafter sometimes referred to as an "organic developer") is used as the developer.

Organic solvents contained in organic developers include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycol ether solvents such as propylene glycol monomethyl ether; amide solvents such as N,N-dimethylacetamide; and aromatic hydrocarbon solvents such as anisole.

In the organic developer, the content of the organic solvent is preferably 90% by weight or more and 100% by weight or less, more preferably 95% by weight or more and 100% by weight or less, and even more preferably substantially only the organic solvent.

Among these, the organic developer is preferably a developer containing butyl acetate and/or 2-heptanone. The total content of butyl acetate and 2-heptanone in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably substantially only butyl acetate and/or 2-heptanone.

The organic developer may contain a surfactant and may contain a small amount of water.
During development, the development may be stopped by replacing the organic developer with a different type of solvent.

It is preferable to wash the resist pattern after development with a rinse solution. There are no particular limitations on the rinse solution as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, preferably an alcohol solvent or an ester solvent.

After cleaning, it is preferable to remove any rinsing liquid remaining on the substrate and the pattern.
<Application>
The resist composition of the present invention is suitable as a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, and is particularly suitable as a resist composition for ArF excimer laser exposure, and is useful for semiconductor microfabrication.

The present invention will be described in more detail with reference to examples. In the examples, "%" and "parts" expressing the content or amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value determined by gel permeation chromatography under the following analytical conditions:

Column: TSKgel Multipore HXL-M x 3+guardcolumn (Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL/min
Detector: RI detector Column temperature: 40℃
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (Tosoh Corporation)
The structure of the compound was confirmed by measuring the molecular ion peak using mass spectrometry (LC: Agilent 1100 model, MASS: Agilent LC/MSD model). In the following examples, the value of this molecular ion peak is indicated by "MASS".

<Example 1: Synthesis of salt represented by formula (I-8)>

4.64 parts of the compound represented by formula (I-8-a) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. The resulting mixture was cooled to 0°C, and then 0.60 parts of sodium hydride was mixed and stirred at 0°C for 4 hours. 6.34 parts of the salt represented by formula (I-8-b) were added to the resulting mixture at 0°C and stirred at 0°C for 3 hours. 27 parts of 1N hydrochloric acid were added to the resulting mixture, and the temperature was raised to 23°C and stirred at 23°C for 6 hours. 60 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, and then the organic layer was separated and taken out. The resulting organic layer was concentrated, and then 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant liquid was removed and concentrated to obtain 5.89 parts of the salt represented by formula (I-8-c).

4.71 parts of the salt represented by formula (I-8-c) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes, after which 0.69 parts of potassium carbonate and 0.21 parts of potassium iodide were added and the temperature was raised to 75°C. 1.95 parts of the compound represented by formula (I-8-d) were added to the resulting mixture, stirred at 75°C for 5 hours, and then cooled to 23°C. 50 parts of chloroform and 20 parts of a 5% aqueous oxalic acid solution were added to the resulting mixture, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. 20 parts of ion-exchanged water were added to the resulting organic layer, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. This water washing operation was repeated five times. The resulting organic layer was concentrated to obtain 5.12 parts of the salt represented by formula (I-8-e).

3.15 parts of the salt represented by formula (I-8-e), 3.20 parts of the salt represented by formula (I-8-f), 50 parts of chloroform, and 10 parts of ethyl acetate were mixed and stirred at 23°C for 2 hours. 30 parts of ion-exchanged water was added to the resulting mixture and stirred at 23°C for 30 minutes, and then the organic layer was separated and extracted. This water washing operation was repeated five times. The resulting organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 4.78 parts of the salt represented by formula (I-8).

MASS (ESI (+) Spectrum): M ⁺ 593.2
MASS (ESI (-) Spectrum): M ^- 517.1
Example 2: Synthesis of salt represented by formula (I-248)

7.16 parts of the compound represented by formula (I-248-a) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. The resulting mixture was cooled to 0°C, and then 0.60 parts of sodium hydride was mixed and stirred at 0°C for 4 hours. 6.34 parts of the salt represented by formula (I-8-b) were added to the resulting mixture at 0°C and stirred at 0°C for 3 hours. 27 parts of 1N hydrochloric acid were added to the resulting mixture, and the temperature was raised to 23°C and stirred at 23°C for 6 hours. 60 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, and then the organic layer was separated and taken out. The resulting organic layer was concentrated, and then 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant liquid was removed and concentrated to obtain 6.99 parts of the salt represented by formula (I-248-c).

5.97 parts of the salt represented by formula (I-248-c) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes, after which 0.69 parts of potassium carbonate and 0.21 parts of potassium iodide were added and the temperature was raised to 75°C. 1.95 parts of the compound represented by formula (I-8-d) were added to the resulting mixture, stirred at 75°C for 5 hours, and then cooled to 23°C. 50 parts of chloroform and 20 parts of a 5% aqueous oxalic acid solution were added to the resulting mixture, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. 20 parts of ion-exchanged water were added to the resulting organic layer, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. This water washing operation was repeated five times. The resulting organic layer was concentrated to obtain 5.24 parts of the salt represented by formula (I-248-e).

3.78 parts of the salt represented by formula (I-248-e), 3.20 parts of the salt represented by formula (I-8-f), 50 parts of chloroform, and 10 parts of ethyl acetate were mixed and stirred at 23°C for 2 hours. 30 parts of ion-exchanged water was added to the resulting mixture and stirred at 23°C for 30 minutes, and then the organic layer was separated and extracted. This water washing operation was repeated five times. The resulting organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 5.33 parts of the salt represented by formula (I-248).

MASS (ESI (+) Spectrum): M ⁺ 719.1
MASS (ESI (-) Spectrum): M ^- 517.1
Example 3: Synthesis of salt represented by formula (I-328)

7.16 parts of the compound represented by formula (I-328-a) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. The resulting mixture was cooled to 0°C, and then 0.60 parts of sodium hydride was mixed and stirred at 0°C for 4 hours. 6.34 parts of the salt represented by formula (I-8-b) were added to the resulting mixture at 0°C and stirred at 0°C for 3 hours. 27 parts of 1N hydrochloric acid were added to the resulting mixture, and the temperature was raised to 23°C and stirred at 23°C for 6 hours. 60 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, and then the organic layer was separated and taken out. The resulting organic layer was concentrated, and then 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant liquid was removed and concentrated to obtain 6.23 parts of the salt represented by formula (I-328-c).

5.97 parts of the salt represented by formula (I-328-c) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes, after which 0.69 parts of potassium carbonate and 0.21 parts of potassium iodide were added and the temperature was raised to 75°C. 1.95 parts of the compound represented by formula (I-8-d) were added to the resulting mixture, stirred at 75°C for 5 hours, and then cooled to 23°C. 50 parts of chloroform and 20 parts of a 5% aqueous oxalic acid solution were added to the resulting mixture, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. 20 parts of ion-exchanged water were added to the resulting organic layer, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. This water washing operation was repeated five times. The resulting organic layer was concentrated to obtain 4.01 parts of the salt represented by formula (I-328-e).

3.78 parts of the salt represented by formula (I-328-e), 3.20 parts of the salt represented by formula (I-8-f), 50 parts of chloroform, and 10 parts of ethyl acetate were mixed and stirred at 23°C for 2 hours. 30 parts of ion-exchanged water was added to the resulting mixture and stirred at 23°C for 30 minutes, and then the organic layer was separated and extracted. This water washing operation was repeated five times. The resulting organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 5.37 parts of the salt represented by formula (I-328).

MASS (ESI (+) Spectrum): M ⁺ 719.1
MASS (ESI (-) Spectrum): M ^- 517.1
Example 4: Synthesis of salt represented by formula (I-3288)

4.64 parts of the compound represented by formula (I-8-a) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. The resulting mixture was cooled to 0°C, and then 0.60 parts of sodium hydride was mixed and stirred at 0°C for 4 hours. 6.30 parts of the salt represented by formula (I-3288-b) were added to the resulting mixture at 0°C and stirred at 0°C for 3 hours. 27 parts of 1N hydrochloric acid were added to the resulting mixture, and the temperature was raised to 23°C and stirred at 23°C for 6 hours. 60 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, and then the organic layer was separated and taken out. The resulting organic layer was concentrated, and then 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant liquid was removed and concentrated to obtain 5.91 parts of the salt represented by formula (I-3288-c).

4.69 parts of the salt represented by formula (I-3288-c) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes, after which 0.69 parts of potassium carbonate and 0.21 parts of potassium iodide were added and the temperature was raised to 75°C. 1.95 parts of the compound represented by formula (I-8-d) were added to the resulting mixture, stirred at 75°C for 5 hours, and then cooled to 23°C. 50 parts of chloroform and 20 parts of a 5% aqueous oxalic acid solution were added to the resulting mixture, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. 20 parts of ion-exchanged water were added to the resulting organic layer, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. This water washing operation was repeated five times. The resulting organic layer was concentrated to obtain 5.23 parts of the salt represented by formula (I-3288-e).

3.14 parts of the salt represented by formula (I-3288-e), 3.20 parts of the salt represented by formula (I-8-f), 50 parts of chloroform, and 10 parts of ethyl acetate were mixed and stirred at 23°C for 2 hours. 30 parts of ion-exchanged water was added to the resulting mixture and stirred at 23°C for 30 minutes, and then the organic layer was separated and extracted. This water washing operation was repeated five times. The resulting organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 4.89 parts of the salt represented by formula (I-3288).

MASS (ESI (+) Spectrum): M ⁺ 591.2
MASS (ESI (-) Spectrum): M ^- 517.1
Example 5: Synthesis of salt represented by formula (I-6848)

4.64 parts of the compound represented by formula (I-8-a) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. The resulting mixture was cooled to 0°C, and then 0.60 parts of sodium hydride was mixed and stirred at 0°C for 4 hours. 8.09 parts of the salt represented by formula (I-6848-b) were added to the resulting mixture at 0°C and stirred at 0°C for 3 hours. 27 parts of 1N hydrochloric acid were added to the resulting mixture, and the temperature was raised to 23°C and stirred at 23°C for 6 hours. 60 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, and then the organic layer was separated and taken out. The resulting organic layer was concentrated, and then 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant liquid was removed and concentrated to obtain 6.87 parts of the salt represented by formula (I-6848-c).

5.59 parts of the salt represented by formula (I-6848-c) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes, after which 0.69 parts of potassium carbonate and 0.21 parts of potassium iodide were added and the temperature was raised to 75°C. 1.95 parts of the compound represented by formula (I-8-d) were added to the resulting mixture, stirred at 75°C for 5 hours, and then cooled to 23°C. 50 parts of chloroform and 20 parts of a 5% aqueous oxalic acid solution were added to the resulting mixture, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. 20 parts of ion-exchanged water were added to the resulting organic layer, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. This water washing operation was repeated five times. The resulting organic layer was concentrated to obtain 5.60 parts of the salt represented by formula (I-6848-e).

3.58 parts of the salt represented by formula (I-6848-e), 3.20 parts of the salt represented by formula (I-8-f), 50 parts of chloroform, and 10 parts of ethyl acetate were mixed and stirred at 23°C for 2 hours. 30 parts of ion-exchanged water was added to the resulting mixture and stirred at 23°C for 30 minutes, and then the organic layer was separated and extracted. This water washing operation was repeated five times. The resulting organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 5.40 parts of the salt represented by formula (I-6848).

MASS (ESI (+) Spectrum): M ⁺ 681.1
MASS (ESI (-) Spectrum): M ^- 517.1
Example 6: Synthesis of salt represented by formula (I-848)

7.44 parts of the compound represented by formula (I-848-a) and 60 parts of chloroform were mixed and stirred at 23°C for 30 minutes, after which 3.24 parts of the compound represented by formula (I-848-b) were added, the mixture was heated to 50°C, and then stirred at 50°C for 2 hours. 6.30 parts of the salt represented by formula (I-848-c) were added to the resulting reaction mixture, stirred at 50°C for 3 hours, and then cooled to 23°C. 30 parts of 1N hydrochloric acid were added to the resulting mixture, stirred at 23°C for 6 hours, and then separated to extract the organic layer. The resulting organic layer was concentrated, and then 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, stirred at 23°C for 30 minutes, the supernatant liquid was removed, and the mixture was concentrated to obtain 9.94 parts of the salt represented by formula (I-848-d).

6.11 parts of the salt represented by formula (I-848-d) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes, after which 0.69 parts of potassium carbonate and 0.21 parts of potassium iodide were added and the temperature was raised to 75°C. 1.95 parts of the compound represented by formula (I-8-d) were added to the resulting mixture, stirred at 75°C for 5 hours, and then cooled to 23°C. 50 parts of chloroform and 20 parts of a 5% aqueous oxalic acid solution were added to the resulting mixture, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. 20 parts of ion-exchanged water were added to the resulting organic layer, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. This water washing operation was repeated five times. The resulting organic layer was concentrated to obtain 6.82 parts of the salt represented by formula (I-848-e).

3.85 parts of the salt represented by formula (I-848-e), 3.20 parts of the salt represented by formula (I-8-f), 50 parts of chloroform, and 10 parts of ethyl acetate were mixed and stirred at 23°C for 2 hours. 30 parts of ion-exchanged water was added to the resulting mixture and stirred at 23°C for 30 minutes, and then the organic layer was separated and extracted. This water washing operation was repeated five times. The resulting organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 5.38 parts of the salt represented by formula (I-848).

MASS (ESI (+) Spectrum): M ⁺ 733.0
MASS (ESI (-) Spectrum): M ^- 517.1
Example 7: Synthesis of salt represented by formula (I-1048)

9.40 parts of the compound represented by formula (I-1048-a) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. The resulting mixture was cooled to 0°C, and then 0.60 parts of sodium hydride was mixed and stirred at 0°C for 4 hours. 6.34 parts of the salt represented by formula (I-8-b) were added to the resulting mixture at 0°C and stirred at 0°C for 3 hours. 27 parts of 1N hydrochloric acid were added to the resulting mixture, and the temperature was raised to 23°C and stirred at 23°C for 6 hours. 60 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, and then the organic layer was separated and taken out. The resulting organic layer was concentrated, and then 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant liquid was removed and concentrated to obtain 7.15 parts of the salt represented by formula (I-1048-c).

7.08 parts of the salt represented by formula (I-1048-c) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes, after which 0.69 parts of potassium carbonate and 0.21 parts of potassium iodide were added and the temperature was raised to 75°C. 1.95 parts of the compound represented by formula (I-8-d) were added to the resulting mixture, stirred at 75°C for 5 hours, and then cooled to 23°C. 50 parts of chloroform and 20 parts of a 5% aqueous oxalic acid solution were added to the resulting mixture, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. 20 parts of ion-exchanged water were added to the resulting organic layer, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. This water washing operation was repeated five times. The resulting organic layer was concentrated to obtain 7.23 parts of the salt represented by formula (I-1048-e).

4.33 parts of the salt represented by formula (I-1048-e), 3.20 parts of the salt represented by formula (I-8-f), 50 parts of chloroform, and 10 parts of ethyl acetate were mixed and stirred at 23°C for 2 hours. 30 parts of ion-exchanged water was added to the resulting mixture and stirred at 23°C for 30 minutes, and then the organic layer was separated and extracted. This water washing operation was repeated five times. The resulting organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 6.01 parts of the salt represented by formula (I-1048).

MASS (ESI (+) Spectrum): M ⁺ 830.9
MASS (ESI (-) Spectrum): M ^- 517.1
Example 8: Synthesis of salt represented by formula (I-2296)

7.16 parts of the compound represented by formula (I-328-a) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. The resulting mixture was cooled to 0°C, and then 0.60 parts of sodium hydride was mixed and stirred at 0°C for 4 hours. 9.06 parts of the salt represented by formula (I-2296-b) were added to the resulting mixture at 0°C and stirred at 0°C for 3 hours. 27 parts of 1N hydrochloric acid were added to the resulting mixture, and the temperature was raised to 23°C and stirred at 23°C for 6 hours. 60 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, and then the organic layer was separated and taken out. The resulting organic layer was concentrated, and then 1 part of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant liquid was removed and concentrated to obtain 7.44 parts of the salt represented by formula (I-2296-c).

7.33 parts of the salt represented by formula (I-2296-c) and 30 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes, after which 0.69 parts of potassium carbonate and 0.21 parts of potassium iodide were added and the temperature was raised to 75°C. 1.95 parts of the compound represented by formula (I-8-d) were added to the resulting mixture, stirred at 75°C for 5 hours, and then cooled to 23°C. 50 parts of chloroform and 20 parts of a 5% aqueous oxalic acid solution were added to the resulting mixture, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. 20 parts of ion-exchanged water were added to the resulting organic layer, stirred at 23°C for 30 minutes, and then separated to extract the organic layer. This water washing operation was repeated five times. The resulting organic layer was concentrated to obtain 7.40 parts of the salt represented by formula (I-2296-e).

4.46 parts of the salt represented by formula (I-2296-e), 2.85 parts of the salt represented by formula (I-16-f), 50 parts of chloroform, and 10 parts of ethyl acetate were mixed and stirred at 23°C for 2 hours. 20 parts of ion-exchanged water was added to the resulting mixture and stirred at 23°C for 30 minutes, and then the organic layer was separated and extracted. This water washing operation was repeated five times. The resulting organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 5.95 parts of the salt represented by formula (I-2296).

MASS (ESI (+) Spectrum): M ⁺ 855.0
MASS (ESI (-) Spectrum): M ^- 467.1
Example 9: Synthesis of salt represented by formula (I-13918)

4.46 parts of the salt represented by formula (I-2296-e), 3.22 parts of the salt represented by formula (I-13918-f), 50 parts of chloroform, and 10 parts of ethyl acetate were mixed and stirred at 23°C for 2 hours. 20 parts of ion-exchanged water was added to the resulting mixture and stirred at 23°C for 30 minutes, and then the organic layer was separated and extracted. This water washing operation was repeated five times. The resulting organic layer was concentrated, and 30 parts of tert-butyl methyl ether was added to the concentrated residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 6.22 parts of the salt represented by formula (I-13918).

MASS (ESI (+) Spectrum): M ⁺ 855.0
MASS (ESI (-) Spectrum): M ^- 541.2
<Synthesis of Resin>
The compounds (monomers) used in the synthesis of Resin (A) are shown below. Hereinafter, these compounds will be referred to as "monomer (a1-1-3)" etc. according to their formula numbers.

Synthesis Example 1: Synthesis of Resin A1
As monomers, monomer (a1-1-3), monomer (a1-2-5), monomer (a2-1-3) and monomer (a3-4-2) were used, and the molar ratio [monomer (a1-1-3): monomer (a1-2-5): monomer (a2-1-3): monomer (a3-4-2)] was mixed to be 45: 14: 2.5: 38.5, and propylene glycol monomethyl ether acetate was added in an amount of 1.5 times the total monomer amount to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to this solution in amounts of 1 mol% and 3 mol%, respectively, relative to the total monomer amount, and these were heated at 73 ° C. for about 5 hours. The resulting reaction mixture was poured into a large amount of a methanol/water mixed solvent to precipitate a resin, and the resin was filtered. The obtained resin was dissolved again in propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol/water mixed solvent to precipitate the resin, which was then filtered. This reprecipitation procedure was repeated twice to obtain Resin A1 having a weight average molecular weight of 7.6 x ¹⁰³ in a yield of 68%. Resin A1 has the following structural units.

Synthesis Example 2: Synthesis of Resin X1
Monomer (a4-1-4) was used as a monomer, and methyl isobutyl ketone was added in an amount 1.5 times the mass of the total monomer amount to obtain a solution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to this solution in amounts of 0.7 mol% and 2.1 mol% relative to the total monomer amount, respectively, and the mixture was heated at 75°C for about 5 hours. The resulting reaction mixture was poured into a large amount of a methanol/water mixed solvent to precipitate a resin, which was then filtered to obtain resin X1 having a weight average molecular weight of 1.7 x 10 ⁴ in a yield of 77%. This resin X1 has the following structural units.

<Preparation of Resist Composition>
As shown in Table 2, the following components were mixed and the resulting mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
A1, X1: Resin A1, Resin X1
<Salt (I)>
I-8: Salt represented by formula (I-8) (Example 1)
I-248: Salt represented by formula (I-248) (Example 2)
I-328: Salt represented by formula (I-328) (Example 3)
I-3288: Salt represented by formula (I-3288) (Example 4)
I-6848: Salt represented by formula (I-6848) (Example 5)
I-848: Salt represented by formula (I-848) (Example 6)
I-1048: Salt represented by formula (I-1048) (Example 7)
I-2296: Salt represented by formula (I-2296) (Example 8)
I-13918: Salt represented by formula (I-13918) (Example 9)
<Compound (B)>
IX-1: Synthesized by the method described in JP 2021-178816 A

<Weak Acid Inner Salt (D)>
D1: (Tokyo Chemical Industry Co., Ltd.)

<Solvent>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 3.5 parts <Production of resist pattern and evaluation thereof>
A composition for organic antireflective coating [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer and baked at 205° C. for 60 seconds to form an organic antireflective coating having a thickness of 78 nm. Next, the resist composition described above was spin-coated onto the organic antireflective coating so that the film thickness of the composition layer after drying (pre-baking) would be 100 nm. After coating, the silicon wafer was pre-baked on a direct hot plate at the temperature shown in the "PB" column of Table 2 for 60 seconds to form a composition layer on the silicon wafer.

The composition layer formed on the silicon wafer was exposed to light using an ArF excimer laser stepper for immersion exposure [XT: 1900Gi; ASML, NA = 1.35, 3/4 Annular XY polarization] with a mask for forming a line and space pattern (pitch 100 nm/line 50 nm) while changing the exposure dose stepwise. Ultrapure water was used as the immersion medium.

After exposure, the wafer was post-exposure baked on a hot plate for 60 seconds at the temperature shown in the "PEB" column of Table 2. The silicon wafer was then paddle developed for 60 seconds using a 2.38% aqueous tetramethylammonium hydroxide solution to obtain a resist pattern.

In the resulting resist pattern, the exposure amount at which the line pattern width became 50 nm was defined as effective sensitivity.
<Line Edge Roughness Evaluation (LER)>
The resulting resist pattern was observed and measured for the amplitude of unevenness on the wall surface using a scanning electron microscope. The results are shown in Table 3. The values in the table indicate the standard deviation of the amplitude (nm).

Compared to Comparative Example 1, which used Comparative Composition 1, Test Examples 1 to 9, which used Compositions 1 to 9, had a smaller standard deviation of the amplitude (nm) and a good line edge roughness (LER) evaluation.

The salt of the present invention and the resist composition containing the salt can produce a resist pattern with good line edge roughness (LER), making them suitable for semiconductor microfabrication and extremely useful industrially.

Claims (21)

An acid generator comprising a salt represented by formula (I):

[In formula (I),
X represents a sulfur atom or an iodine atom.
m10 represents 0 or 1, and when X is a sulfur atom, m10 is 1, and when X is an iodine atom, m10 is 0.
Ar ¹ , Ar ² and Ar ³ each independently represent an aromatic hydrocarbon group having 10 to 14 carbon atoms.
R ¹ , R ² and R ³ each independently represent *-O-R ¹⁰ , *-O-CO-R ¹⁰ , *-O-CO-O-R ¹⁰ or *-OL ¹⁰ -CO-O-R ¹⁰ , where * represents a bonding site to Ar ¹ , Ar ² or Ar ³ , respectively.
L ¹⁰ represents an alkanediyl group having 1 to 6 carbon atoms.
R ¹⁰ represents a group having a cyclic carbonate structure.
R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represent a halogen atom, a haloalkyl group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 36 carbon atoms, the hydrocarbon group may have a substituent, and the -CH ₂ - contained in the haloalkyl group and the hydrocarbon group may be replaced with -O-, -S-, -CO-, -SO- or -SO ₂ -. In addition, when X is a sulfur atom, R ⁷ and R ⁸ or R ⁸ and R ⁹ may be bonded to form a ring containing S ⁺ , and the -CH ₂ - contained in the ring may be replaced with -O-, -S-, -CO-, -SO- or -SO ₂ -. R ⁷ and R ⁸ or R ⁸ and R ⁹ forming the ring may be a single bond formed between two benzene rings bonded to S ⁺ .
A ¹ , A ² and A ³ each independently represent a hydrocarbon group having 1 to 20 carbon atoms, the hydrocarbon group may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -CO-, -S- or -SO ₂ -.
m1 represents an integer of 1 to 5, and when m1 is 2 or more, the groups in multiple parentheses may be the same or different.
m2 represents an integer of 0 to 5, and when m2 is 2 or more, the groups in the parentheses may be the same or different.
m3 represents an integer of 0 to 5, and when m3 is 2 or more, the groups in the parentheses may be the same or different.
m4 represents an integer of 0 to 7, and when m4 is 2 or greater, multiple R ^4s may be the same or different.
m5 represents an integer of 0 to 7, and when m5 is 2 or greater, the multiple R ^5s may be the same or different.
m6 represents an integer of 0 to 7, and when m6 is 2 or greater, multiple R ^6s may be the same or different.
m7 represents an integer of 0 to 4, and when m7 is 2 or greater, the multiple R ^7s may be the same or different.
m8 represents an integer of 0 to 5, and when m8 is 2 or greater, multiple R ^8s may be the same or different.
m9 represents an integer of 0 to 5, and when m9 is 2 or more, the multiple R ^9s may be the same or different.
However, 1≦m1+m7≦5, 0≦m2+m8≦5, and 0≦m3+m9≦5.
^AI- represents an organic anion. A ¹ is ***-X ⁰¹ -L ⁰¹ - or ***-L ⁰¹ -X ⁰¹ -;
A ² is ***-X ⁰² -L ⁰² - or ***-L ⁰² -X ⁰² -;
A ³ is ***-X ⁰³ -L ⁰³ - or ***-L ⁰³ -X ⁰³ -;
X ⁰¹ , X ⁰² and X ⁰³ each independently represent —O—, —CO—, —S— or —SO ₂ —;
L ⁰¹ , L ⁰² and L ⁰³ each independently represent a single bond or a hydrocarbon group having 1 to 18 carbon atoms, the hydrocarbon group optionally having a substituent, and -CH ₂ - contained in the hydrocarbon group optionally being replaced by -O-, -CO-, -S- or -SO ₂ -;
The acid generator according to claim 1 , wherein *** represents a bonding site on the benzene ring to which X ⁺ is bonded. 3. The acid generator according to claim 2, wherein X ⁰¹ , X ⁰² and X ⁰³ each independently represent --O-- or --S--. 3. The acid generator according to claim 2, wherein L ⁰¹ , L ⁰² and L ⁰³ each independently represent a single bond or an alkanediyl group having 1 to 6 carbon atoms (-CH ₂ - contained in the alkanediyl group may be replaced by -O- or -CO-). The acid generator according to claim 1 , wherein the group having a cyclic carbonate structure for R ¹⁰ is a group represented by formula (Ix).

[In formula (Ix),
Ring W ^x represents a ring of a cyclic carbonate structure which may have a substituent, and --CH ₂ -- contained in the ring may be replaced by --O--, --CO--, --S-- or --NH--.
L ¹² represents a single bond or a hydrocarbon group having 1 to 36 carbon atoms which may have a substituent, and --CH ₂ -- contained in the hydrocarbon group may be replaced by --O--, --S--, --CO-- or --SO ₂ --.
* indicates a binding site. 2. The acid generator according to claim 1, wherein Ar ¹ , Ar ² and Ar ³ are naphthalene. 2. The acid generator according to claim 1, wherein AI ⁻ is a sulfonate anion, a sulfonylimide anion, or a sulfonylmethide anion. 8. The acid generator according to claim 7, wherein AI ⁻ is a sulfonate anion, which is an anion represented by formula (IA) or an anion represented by formula (IB).

[In formula (IA),
^Q1 and ^Q2 each independently represent a hydrogen atom, a fluorine atom, a perfluoroalkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms.
^L1 represents a saturated hydrocarbon group having 1 to 24 carbon atoms, in which _-CH2- may be replaced by -O- or -CO-, and in which a hydrogen atom may be replaced by a fluorine atom or a hydroxyl group.
^Y1 represents a methyl group which may have a substituent or a cyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, and -CH ₂ - contained in the cyclic hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-.]

[In formula (IB),
m21 represents an integer of 1 to 5, and when m21 is 2 or greater, the groups in the parentheses may be the same or different.
R ²¹ represents a hydrocarbon group having 3 to 48 carbon atoms, including a cyclic hydrocarbon group having 3 to 18 carbon atoms, the cyclic hydrocarbon group may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-.
R ²² represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and --CH ₂ -- contained in the alkyl group may be replaced by --O-- or --CO--.
m22 represents an integer of 0 to 4, and when m22 is 2 or greater, the multiple R ²² may be the same or different. A resist composition containing the acid generator according to any one of claims 1 to 8. Further, the composition contains a resin including a structural unit having an acid labile group,
10. The resist composition according to claim 9, wherein the structural unit having an acid labile group comprises at least one selected from the group consisting of a structural unit represented by formula (a1-0), a structural unit represented by formula (a1-1), and a structural unit represented by formula (a1-2).

[In formula (a1-0), formula (a1-1) and formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent --O-- or *-O--(CH ₂ ) _k1 --CO--O--, where k1 represents an integer of 1 to 7, and * represents a bonding site with --CO--.
R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a02 , R ^a03 and R ^a04 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof.
m1' represents an integer of 0 to 14.
n1 represents an integer of 0 to 10.
n1' represents an integer of 0 to 3. The resist composition according to claim 9, further comprising a resin containing a structural unit having a fluorine atom. The resist composition according to claim 9, further comprising a salt that generates an acid with a lower acidity than the acid generated from the acid generator. (1) A step of applying the resist composition according to claim 9 onto a substrate;
(2) A step of drying the applied composition to form a composition layer;
(3) exposing the composition layer to light;
(4) a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.
A method for producing a resist pattern comprising the steps of: A salt represented by formula (I):

[In formula (I),
X represents a sulfur atom or an iodine atom.
m10 represents 0 or 1, and when X is a sulfur atom, m10 is 1, and when X is an iodine atom, m10 is 0.
Ar ¹ , Ar ² and Ar ³ each independently represent an aromatic hydrocarbon group having 10 to 14 carbon atoms.
R ¹ , R ² and R ³ each independently represent *-O-R ¹⁰ , *-O-CO-R ¹⁰ , *-O-CO-O-R ¹⁰ or *-OL ¹⁰ -CO-O-R ¹⁰ , where * represents a bonding site to Ar ¹ , Ar ² or Ar ³ , respectively.
L ¹⁰ represents an alkanediyl group having 1 to 6 carbon atoms.
R ¹⁰ represents a group having a cyclic carbonate structure.
R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represent a halogen atom, a haloalkyl group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 36 carbon atoms, the hydrocarbon group may have a substituent, and the -CH ₂ - contained in the haloalkyl group and the hydrocarbon group may be replaced with -O-, -S-, -CO-, -SO- or -SO ₂ -. In addition, when X is a sulfur atom, R ⁷ and R ⁸ or R ⁸ and R ⁹ may be bonded to form a ring containing S ⁺ , and the -CH ₂ - contained in the ring may be replaced with -O-, -S-, -CO-, -SO- or -SO ₂ -. R ⁷ and R ⁸ or R ⁸ and R ⁹ forming the ring may be a single bond formed between two benzene rings bonded to S ⁺ .
A ¹ , A ² and A ³ each independently represent a hydrocarbon group having 1 to 20 carbon atoms, the hydrocarbon group may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -CO-, -S- or -SO ₂ -.
m1 represents an integer of 1 to 5, and when m1 is 2 or more, the groups in multiple parentheses may be the same or different.
m2 represents an integer of 0 to 5, and when m2 is 2 or more, the groups in the parentheses may be the same or different.
m3 represents an integer of 0 to 5, and when m3 is 2 or more, the groups in the parentheses may be the same or different.
m4 represents an integer of 0 to 7, and when m4 is 2 or greater, multiple R ^4s may be the same or different.
m5 represents an integer of 0 to 7, and when m5 is 2 or greater, the multiple R ^5s may be the same or different.
m6 represents an integer of 0 to 7, and when m6 is 2 or greater, the multiple R ^6s may be the same or different.
m7 represents an integer of 0 to 4, and when m7 is 2 or greater, the multiple R ^7s may be the same or different.
m8 represents an integer of 0 to 5, and when m8 is 2 or greater, multiple R ^8s may be the same or different.
m9 represents an integer of 0 to 5, and when m9 is 2 or more, the multiple R ^9s may be the same or different.
However, 1≦m1+m7≦5, 0≦m2+m8≦5, and 0≦m3+m9≦5.
^AI- represents an organic anion. A ¹ is ***-X ⁰¹ -L ⁰¹ - or ***-L ⁰¹ -X ⁰¹ -;
A ² is ***-X ⁰² -L ⁰² - or ***-L ⁰² -X ⁰² -;
A ³ is ***-X ⁰³ -L ⁰³ - or ***-L ⁰³ -X ⁰³ -;
X ⁰¹ , X ⁰² and X ⁰³ each independently represent —O—, —CO—, —S— or —SO ₂ —;
L ⁰¹ , L ⁰² and L ⁰³ each independently represent a single bond or a hydrocarbon group having 1 to 18 carbon atoms, the hydrocarbon group optionally having a substituent, and -CH ₂ - contained in the hydrocarbon group optionally being replaced by -O-, -CO-, -S- or -SO ₂ -;
The salt according to claim 14, wherein *** represents a bonding site between the benzene ring and X ⁺ . The salt according to claim 15, wherein X ⁰¹ , X ⁰² and X ⁰³ are each independently -O- or -S-. The salt according to claim 15 or 16, wherein L ⁰¹ , L ⁰² and L ⁰³ each independently represent a single bond or an alkanediyl group having 1 to 6 carbon atoms (-CH ₂ - contained in the alkanediyl group may be replaced by -O- or -CO-). The salt according to claim 14 or 15, wherein the group having a cyclic carbonate structure for R ¹⁰ is a group represented by formula (Ix):

[In formula (Ix),
Ring W ^x represents a ring of a cyclic carbonate structure which may have a substituent, and --CH ₂ -- contained in the ring may be replaced by --O--, --CO--, --S-- or --NH--.
L ¹² represents a single bond or a hydrocarbon group having 1 to 36 carbon atoms which may have a substituent, and --CH ₂ -- contained in the hydrocarbon group may be replaced by --O--, --S--, --CO-- or --SO ₂ --.
* indicates a binding site. 16. The salt according to claim 14 or 15, wherein Ar ¹ , Ar ² and Ar ³ are naphthalene. The salt according to claim 14 or 15, wherein AI ⁻ is a sulfonate anion, a sulfonylimide anion or a sulfonylmethide anion. The salt according to claim 20, wherein AI ⁻ is a sulfonate anion, and the sulfonate anion is an anion represented by formula (IA) or an anion represented by formula (IB).

[In formula (IA),
^Q1 and ^Q2 each independently represent a hydrogen atom, a fluorine atom, a perfluoroalkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms.
^L1 represents a saturated hydrocarbon group having 1 to 24 carbon atoms, in which _-CH2- may be replaced by -O- or -CO-, and in which a hydrogen atom may be replaced by a fluorine atom or a hydroxyl group.
^Y1 represents a methyl group which may have a substituent or a cyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, and -CH ₂ - contained in the cyclic hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-.]

[In formula (IB),
m21 represents an integer of 1 to 5, and when m21 is 2 or greater, the groups in the parentheses may be the same or different.
R ²¹ represents a hydrocarbon group having 3 to 48 carbon atoms, including a cyclic hydrocarbon group having 3 to 18 carbon atoms, the cyclic hydrocarbon group may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be replaced by -O-, -S-, -SO ₂ - or -CO-.
R ²² represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and --CH ₂ -- contained in the alkyl group may be replaced by --O-- or --CO--.
m22 represents an integer of 0 to 4, and when m22 is 2 or more, the multiple R ²² may be the same or different.