JP2019085397A - Salt, acid generator, resist composition, and method for producing resist pattern - Google Patents

Abstract

To provide a salt capable of producing a resist pattern with good line edge roughness (LER), and a resist composition containing the salt.SOLUTION: The salt is represented by formula (I) [where Qand Qeach represent a fluorine atom or a perfluoroalkyl group; Rand Reach represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group; z represents an integer of 0-6; Lrepresents an optionally substituted divalent hydrocarbon group, provided that -CH- contained in the hydrocarbon group may be substituted with -O-, -S-, -CO- or -SO-; Wrepresents an optionally substituted hydrocarbon ring; R, Rand Reach represent a hydrogen atom, a fluorine atom or a hydrocarbon group; and Zrepresents an organic cation].SELECTED DRAWING: None

Description

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

Patent Document 1 describes a resist composition containing a salt represented by the following formula as an acid generator.
Patent Document 2 describes a resist composition containing a salt represented by the following formula as an acid generator.
Patent Document 3 describes a resist composition containing a salt represented by the following formula as an acid generator.

JP, 2012-144516, A JP, 2009-137873, A JP, 2013-053137, A

  An object of the present invention is to provide a salt capable of producing better line edge roughness (LER) than a resist pattern formed from the above-described resist composition.

The present invention includes the following inventions.
[1] A salt represented by the formula (I).
[In the formula (I),
Each of Q ¹ and Q ² independently represents a fluorine atom or a C 1 to C 6 perfluoroalkyl group.
R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or a C ^{1 to} C 6 perfluoroalkyl group.
z represents any integer of 0 to 6, and when z is 2 or more, plural R ^{1 s} and R ^{2 s} may be the same as or different from each other.
L ¹ represents a divalent hydrocarbon group having 1 to 36 carbon atoms which may have a substituent, and -CH _2- contained in the hydrocarbon group is -O-, -S-,- It may be replaced by CO- or -SO _2- .
W ¹ represents a hydrocarbon ring of 3 to 18 carbon atoms which may have a substituent, and -CH _2- contained in the hydrocarbon ring is -O-, -S-, -CO- or It may be replaced by -SO _2- .
R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom, a fluorine atom or a hydrocarbon group having 1 to 12 carbon atoms, and -CH _2- contained in the hydrocarbon group is -O- or- It may be replaced by CO-.
Z ⁺ represents an organic cation. ]
[2] L ¹ is * -CO-O-L ² -or * -O-CO-L ^2- (L ² is a single bond, an alkanediyl group having 1 to 6 carbon atoms, or 1 to 6 carbon atoms Represents a group in which an alkanediyl group and an alicyclic hydrocarbon group having 3 to 18 carbon atoms are combined, and -CH _2- contained in L ¹ is -O-, -S-, -CO- or -SO ₂ The salt according to [1], which may be replaced by-and * represents a bonding position with C (R ¹ ) (R ² ) or C (Q ¹ ) (Q ² ).
[3] The salt according to [1] or [2], wherein W ¹ is an adamantane ring.
[4] The salt according to any one of [1] to [3], wherein R ⁴ is a hydrogen atom or a fluorine atom.
[5] The salt according to any one of [1] to [4], wherein R ³ and R ⁵ are hydrogen atoms.
The acid generator containing the salt in any one of [6] [1]-[5].
[7] A resist composition comprising the acid generator according to [6] and a resin having an acid labile group.
[8] The resist composition according to [7], which contains a salt that generates an acid having a weaker acidity than an acid generated from an acid generator.
[9] A step of applying the resist composition as described in [1] [7] or [8] on a substrate,
(2) drying the composition after application to form a composition layer;
(3) exposing the composition layer,
(4) A method of producing a resist pattern comprising the steps of heating the composition layer after exposure and (5) developing the composition layer after heating.

  By using a resist composition using the salt of the present invention, a resist pattern can be produced with good line edge roughness (LER).

In the present specification, “(meth) acrylic monomer” means a monomer having a structure of “CH ₂ CHCH—CO—” and a monomer having a structure of “CH ₂ CC (CH ₃ ) —CO—”. At least one selected from the group consisting of Similarly, “(meth) acrylate” and “(meth) acrylic acid” are “at least one selected from the group consisting of acrylate and methacrylate” and “at least one selected from the group consisting of acrylic acid and methacrylic acid, respectively. Means ". When a structural unit having "CH ₂ CC (CH ₃ ) -CO-" or "CH ₂ CHCH-CO-" is exemplified, structural units having both groups are exemplified similarly. It shall be. Moreover, in the groups described in the present specification, any of those which can have both a linear structure and a branched structure may be used. Where stereoisomers exist, all stereoisomers are included.

<Salt (I)>
The salt of the present invention is a salt represented by the formula (I) (hereinafter sometimes referred to as "salt (I)").
In formula (I), as a perfluoroalkyl group of Q ¹ , Q ² , R ¹ and R ² , a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group And perfluoro tert-butyl group, perfluoropentyl group, perfluorohexyl group and the like.
Each of Q ¹ and Q ² is preferably independently a trifluoromethyl group or a fluorine atom, more preferably a fluorine atom.
Each of R ¹ and R ² independently is preferably a hydrogen atom or a fluorine atom.
z is preferably 0.

Examples of the divalent hydrocarbon group having 1 to 36 carbon atoms of L ¹ include an alkanediyl group, a monocyclic or polycyclic divalent alicyclic hydrocarbon group, a divalent aromatic hydrocarbon group, and the like. It may be a divalent hydrocarbon group in which two or more of these groups are combined.

As an alkanediyl group, a methylene group, ethylene group, propane-1,3-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, dodecane-1,12-diyl group A linear alkanediyl group such as a group;
Ethan-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- Examples thereof include branched alkanediyl groups such as 1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group.
As a monocyclic divalent alicyclic hydrocarbon group, cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclohexene-3,6- Examples include cycloalkanediyl groups such as diyl group and cyclooctane-1,5-diyl group.
As the polycyclic divalent alicyclic hydrocarbon group, norbornane-1,4-diyl group, norbornane-2,5-diyl group, 5-norbornene-2,3-diyl group, adamantane-1,5 -Diyl group, adamantane 2, 6- diyl group etc. are mentioned.
Examples of the divalent aromatic hydrocarbon group include phenylene group, naphthylene group, anthrylene group, biphenylene group, phenanthrylene group and the like.
As a bivalent hydrocarbon group which combined 2 or more types, the group etc. which combined the alkanediyl group and the alicyclic hydrocarbon group and / or the aromatic hydrocarbon group are mentioned, and-cycloalkanediyl-alkanediyl -, -Alkanediyl-cycloalkanediyl-, -Alkanediyl-cycloalkanediyl-Alkanediyl-, -Alkanediyl-aromatic hydrocarbon group-, -Aromatic hydrocarbon group-Alkanediyl- and the like.

As a substituent which the hydrocarbon group of L ¹ has, a hydroxy group, a cyano group, a carboxyl group, a C1-C12 alkoxy group, a C2-C13 acyl group, a C2-C13 acyloxy group, and these The group which combined 2 or more types among group of is mentioned.
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 and a hexyloxy group.
As a C2-C13 acyl group, an acetyl group, a propionyl group, and a butyryl group are mentioned.
As a C2-C13 acyloxy group, an acetyloxy group, a propionyloxy group, a butyryloxy group etc. are mentioned.
The divalent hydrocarbon group having 1 to 36 carbon atoms represented by L ¹ may have one substituent or a plurality of substituents.

-CH ₂ contained in the divalent hydrocarbon group having a carbon number of 1 to 36 of L ¹ - is, -O -, - S -, - CO- or -SO ₂ - may be replaced with.
When the divalent hydrocarbon group having 1 to 36 carbon atoms of L ¹ has a substituent or -CH _2- contained in the hydrocarbon group is -O-, -S-, -CO- or -SO _2- When it substitutes, carbon number before substituting is made into carbon number of this hydrocarbon group.

Examples of the group in which —CH ₂ — contained in the hydrocarbon group of L ¹ is a group replaced by —O—, —S—, —CO— or —SO ₂ — include, for example, a group represented by formula (b1-1) to a group A group represented by any of-3) is mentioned. In the groups represented by the formulas (b1-1) to (b1-3) and the groups represented by the formulas (b1-4) to (b1-11) which are specific examples thereof, * represents W ^This represents the binding site to ¹ .

[In the 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 by a fluorine atom.
L ^b3 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 by a fluorine atom or a hydroxy group, and the saturated The —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
However, the total carbon number of 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 by a fluorine atom.
L ^b5 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 by a fluorine atom or a hydroxy group, and the saturated The —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
However, the total carbon number of 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 by 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, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted by a fluorine atom or a hydroxy group, and the saturated The —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
However, the total carbon number of L ^b6 and L ^b7 is 23 or less. ]

In the groups represented by Formula (b1-1) to Formula (b1-3), when -CH _2- contained in a saturated hydrocarbon group is replaced by -O- or -CO-, carbon before replacement is Let the number be the carbon number of the saturated hydrocarbon group.
As the divalent saturated hydrocarbon group, an alkanediyl group of L ¹ , a monocyclic or polycyclic divalent alicyclic hydrocarbon group, and the same ones as combinations of two or more of these groups are used. It can be mentioned.

L ^b2 is preferably a single bond.
L ^b3 is preferably a divalent C 1 to C 4 saturated hydrocarbon group.
L ^b4 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted by a fluorine atom.
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 the hydrogen atom contained in the saturated hydrocarbon group may be substituted by a fluorine atom.
L ^b7 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted by a fluorine atom or a hydroxy group, -CH ₂ contained in the divalent saturated hydrocarbon group - may be replaced by -O- or -CO-.

-CH ₂ contained in the hydrocarbon group of L ¹ - as has been replaced by -O- or -CO- group, a group represented by the formula (b1-1) or the formula (b1-3) is preferable.

As group represented by Formula (b1-1), group represented by Formula (b1-4)-Formula (b1-8) is mentioned, respectively.
[In the 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 by a fluorine atom or a hydroxy group.
In formula (b1-5),
L ^b9 represents a C 1 to C 20 divalent saturated hydrocarbon group, 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 by a fluorine atom or a hydroxy group .
However, the total carbon number of L ^b9 and L ^b10 is 20 or less.
In formula (b1-6),
L ^b11 represents a bivalent 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 by a fluorine atom or a hydroxy group .
However, the total carbon number of L ^b11 and L ^b12 is 21 or less.
In the formula (b1-7),
L ^b13 represents a divalent C 1-19 saturated hydrocarbon group.
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 is replaced by -O- or -CO- It is also good.
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 by a fluorine atom or a hydroxy group .
However, the total carbon number 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 ^C 1 to ^C 18 saturated hydrocarbon group.
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 by a fluorine atom or a hydroxy group .
However, the total carbon number 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, and more preferably an alkanediyl group, a divalent alicyclic hydrocarbon group and an alkanediyl group and a divalent alicyclic hydrocarbon It is a group in combination with a hydrogen group.
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 C 1 to C 12 saturated hydrocarbon group.
L ^b17 is preferably a divalent C 1 to ^C 6 saturated hydrocarbon group.
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.

As group represented by Formula (b1-3), group represented by Formula (b1-9)-Formula (b1-11) is mentioned, respectively.
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 by 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 is substituted by a fluorine atom, a hydroxy group or an alkylcarbonyloxy group It is also good. -CH _2- contained in the alkylcarbonyloxy group may be replaced by -O- or -CO-, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted by a hydroxy group.
However, the total carbon number of L ^b19 and L ^b20 is 23 or less.
In the 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 by 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 is substituted by a fluorine atom, a hydroxy group or an alkylcarbonyloxy group It is also good. -CH _2- contained in the alkylcarbonyloxy group may be replaced by -O- or -CO-, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted by a hydroxy group.
However, the total carbon number 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 by a fluorine atom.
L ^b25 represents a bivalent 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 is substituted by a fluorine atom, a hydroxy group or an alkylcarbonyloxy group; It is also good. -CH _2- contained in the alkylcarbonyloxy group may be replaced by -O- or -CO-, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted by a hydroxy group.
However, L ^b24, the total number of carbon atoms of L ^b25 and L ^b26 is 21 or less.

  In the group represented by the formula (b1-9) to the group represented by the formula (b1-11), when a hydrogen atom contained in a saturated hydrocarbon group is substituted by an alkylcarbonyloxy group, it is replaced Let the previous carbon number be the carbon number of the saturated hydrocarbon group.

  Examples of the alkylcarbonyloxy group include acetyloxy group, propionyloxy group, butyryloxy group, cyclohexylcarbonyloxy group, adamantyl carbonyloxy group and the like.

Examples of the group represented by formula (b1-4) include the following.
(* And ** represent a binding site, * represents a binding site to Y.)

Examples of the group represented by formula (b1-5) include the following.
(* And ** represent a binding site, * represents a binding site to Y.)

Examples of the group represented by formula (b1-6) include the following.
(* And ** represent a binding site, * represents a binding site to Y.)

Examples of the group represented by formula (b1-7) include the following.
(* And ** represent a binding site, * represents a binding site to Y.)

Examples of the group represented by formula (b1-8) include the following.
(* And ** represent a binding site, * represents a binding site to Y.)

Examples of the group represented by the formula (b1-2) include the following.
(* And ** represent a binding site, * represents a binding site to Y.)

Examples of the group represented by the formula (b1-9) include the following.
(* And ** represent a binding site, * represents a binding site to Y.)

Examples of the group represented by formula (b1-10) include the following.
(* And ** represent a binding site, * represents a binding site to Y.)

Examples of the group represented by formula (b1-11) include the following.
(* And ** represent a binding site, * represents a binding site to Y.)

L ¹ is preferably * -CO-O-L ² -or * -O-CO-L ^2- . Here, L ² represents a single bond, an alkanediyl group having 1 to 6 carbon atoms, or a combination of an alkanediyl group having 1 to 6 carbon atoms and an alicyclic hydrocarbon group having 3 to 18 carbon atoms. In this case, -CH _2- contained in L ¹ may be further replaced by -O-, -S-, -CO- or -SO _2- . * Represents a bonding position with C (R ¹ ) (R ² ) or C (Q ¹ ) (Q ² ).

As L ¹ , the following groups may be mentioned.

The hydrocarbon ring represented by W ¹ represents a non-aromatic hydrocarbon ring and an aromatic hydrocarbon ring.
The non-aromatic hydrocarbon ring may be any of monocyclic, polycyclic and spiro ring, and may be either saturated or unsaturated. As a non-aromatic hydrocarbon ring, monocyclic non-aromatic hydrocarbon rings such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cyclooctane, cyclononane, cyclodecane, cyclododecane and the like, norbornane, norbornene, adamantane and the like Included are polycyclic non-aromatic hydrocarbon rings. The carbon number of the non-aromatic hydrocarbon ring is preferably 5 to 18, more preferably 6 to 12.
The aromatic hydrocarbon ring includes aromatic hydrocarbon rings such as benzene, naphthalene, biphenyl, phenanthrene and binaphthyl. The carbon number of the aromatic hydrocarbon ring is preferably 6 to 14, and more preferably 6 to 10.
When —CH ₂ — contained in the hydrocarbon ring represented by W ¹ is replaced by —O—, —S—, —CO— or —S (O) ₂ —, the carbon number before replacement is the carbon number The total carbon number of the hydrogen ring.

The hydrocarbon ring represented by W ¹ may have one or more substituents. Examples of the substituent include a hydroxy group, a halogen atom, a cyano group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, and an alkyl having 2 to 13 carbon atoms. Examples thereof include a carbonyl group, an alkylcarbonyloxy group having 2 to 13 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and a combination of these.
The halogen atom includes 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 methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group and dodecyl group. .
Examples of the alkoxy group having 1 to 12 carbon atoms include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, undecyloxy And dodecyloxy groups.
An alkoxycarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyl group having 2 to 13 carbon atoms and an alkylcarbonyloxy group having 2 to 13 carbon atoms are groups in which a carbonyl group or a carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group. Represents A methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl group etc. are mentioned as a C2-C13 alkoxycarbonyl group, Acetyl group, a propionyl group, a butyryl group etc. are mentioned as a C2-C13 alkylcarbonyl group. As the alkylcarbonyloxy group having 2 to 13 carbon atoms, an acetyloxy group, a propionyloxy group, a butyryloxy group and the like can be mentioned.
As a C3-C12 alicyclic hydrocarbon group, the group shown below is mentioned. ** represents a bonding site to a hydrocarbon group.
As a combined group in the substituent of W ^1, a group obtained by combining a hydroxy group and an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms and an aromatic hydrocarbon group having 6 to 10 carbon atoms And the like.
As a group which combined the hydroxyl group and the C1-C12 alkyl group, C1-C12 hydroxyalkyl groups, such as a hydroxymethyl group and a hydroxyethyl group, etc. are mentioned.
As a group which combined the C1-C12 alkyl group and the C6-C10 aromatic hydrocarbon group, C7-C22 aralkyl groups, such as a benzyl group, etc. are mentioned.

W ¹ represents a hydrocarbon ring having a polycyclic structure which may have a substituent, provided that —CH ₂ — contained in the hydrocarbon ring is —O—, —S—, —CO— or —S (O) _2- may be substituted), adamantane, norbornane, norbornene or cyclohexane is more preferable, and adamantane is more preferable.

Examples of the hydrocarbon group represented by R ³ , R ⁴ and R ⁵ include a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group.
The chain hydrocarbon group includes an alkyl group, an alkenyl group and an alkynyl group.
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.
Examples of the alkenyl group include vinyl group (ethenyl group), allyl group (2-propenyl group), isopropenyl group (1-methylethenyl group) and the like.
Examples of the alkynyl group include ethynyl group, propynyl group and butynyl group.
As an alicyclic hydrocarbon group, a cyclopropyl group, cyclobutyl group, a cyclopentyl group, a cyclohexyl group etc. are mentioned.
The aromatic hydrocarbon group includes a phenyl group.
As a group in which -CH _2- contained in a hydrocarbon group is replaced by -O- or -CO-, a hydroxy group, a carboxyl group, a methoxy group, a methylcarbonyl group, a methoxycarbonyl group, a methylcarbonyloxy group, a methoxycarbonyloxy group is mentioned Groups, ethoxy group, methoxymethyl group, ethoxymethyl group, methoxymethoxy group and the like.
When -CH _2- contained in the hydrocarbon group represented by R ³ , R ⁴ and R ⁵ is replaced by -O-, -S-, -CO- or -SO _2- , the number of carbons before replacement is Is the total carbon number of the hydrocarbon group.
R ³ and R ⁵ are preferably hydrogen atoms.
R ⁴ is preferably a hydrogen atom or a fluorine atom.

As anion (I), the anion represented by the following formula (Ia-1)-formula (Ia-18) is mentioned, for example. Among them, anions represented by formulas (Ia-1) to (Ia-14) are preferable.

Examples of the organic cation of Z ⁺ include organic onium cation, organic sulfonium cation, organic iodonium cation, organic ammonium cation, benzothiazolium cation, organic phosphonium cation and the like. Among these, organic sulfonium cations and organic iodonium cations are preferable, and arylsulfonium cations are more preferable. Specifically, the cation represented by any one of formulas (b2-1) to (b2-4) (hereinafter, sometimes referred to as "cation (b2-1)" or the like depending on the formula number) is It can be mentioned.

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, The hydrogen atom contained in the chain hydrocarbon group is 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 The hydrogen atom contained in the alicyclic hydrocarbon group may be a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkyl carbonyl group having 2 to 4 carbon atoms, or a glycidyloxy group. It may be substituted, and a hydrogen atom contained in the aromatic hydrocarbon group may be substituted by a halogen atom, a hydroxy group or an alkoxy group having 1 to 12 carbon atoms.
R ^b4 and R ^b5 may combine with each other to form a ring together with the sulfur atom to which they are attached, and the —CH ₂ — contained in the ring is —O—, —S— or It may replace -CO-.
R ^b7 and R ^b8 each independently represent a hydroxy group, an aliphatic hydrocarbon 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, the plurality of R ^b7 may be the same or different, and when n2 is 2 or more, the plurality of R ^b8 may be the same or different.
R ^b9 and R ^b10 each independently represent a C1-C36 chain hydrocarbon group or a C3-C36 alicyclic hydrocarbon group.
R ^b9 and R ^b10 may be combined with each other to form a ring together with the sulfur atom to which they are attached, and -CH _2- contained in the ring is -O-, -S- or It may replace -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 a 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, and is included in the chain hydrocarbon The hydrogen atom to be substituted may be substituted by an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group is an alkoxy group having 1 to 12 carbon atoms or 1 to 1 carbon atom. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may combine with each other to form a ring including -CH-CO- to which they are bonded, and -CH _2- contained in the ring is -O-, -S -Or -CO- may be substituted.
Each of R ^{b13 to} R ^b18 independently represents a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.
L ^b31 represents a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represent any integer of 0 to 5;
Each of q2 and r2 independently represents an integer of 0 to 4.
u2 represents 0 or 1;
When o2 is 2 or more, the plurality of R ^b13 are the same or different, and when p2 is 2 or more, the plurality of R ^b14 is the same or different, and when q2 is 2 or more, the plurality of R ^b15 is the same or different , When r2 is 2 or more, the plurality of R ^b16 are the same or different; when s2 is 2 or more, the plurality of R ^b17 is the same or different; when t2 is 2 or more, the plurality of R ^b18 is the same or phase It is different.

The aliphatic hydrocarbon group represents a chain hydrocarbon group and an alicyclic hydrocarbon group.
As a chain hydrocarbon group, an alkyl group of methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group and 2-ethylhexyl group is preferable. It can be mentioned.
In particular, the chain hydrocarbon group of R ^{b9 to} R ^b12 preferably has 1 to 12 carbon atoms.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and as the monocyclic alicyclic hydrocarbon group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclocyclo group And cycloalkyl groups such as heptyl group, cyclooctyl group and cyclodecyl group. As a polycyclic alicyclic hydrocarbon group, a decahydronaphthyl group, an adamantyl group, a norbornyl group, the following groups, etc. are mentioned.
In particular, the alicyclic hydrocarbon group of R ^{b9 to} R ^b12 preferably has 3 to 18 carbon atoms, and more preferably 4 to 12 carbon atoms.

  As an alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group, a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-methyladamantan-2-yl group, a 2-ethyladamantan-2-yl group And 2-isopropyladamantan-2-yl group, methyl norbornyl group, isobornyl group and the like. In an alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group, the total carbon number of the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.

Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, biphenylyl group, naphthyl group and phenanthryl group.
The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and is an aromatic hydrocarbon group having a chain hydrocarbon group having 1 to 18 carbon atoms (tolyl group , Xylyl group, cumenyl group, mesityl group, p-ethylphenyl group, p-tert-butylphenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), and having 3 to 18 carbon atoms The aromatic hydrocarbon group (p-cyclohexylphenyl group, p-adamantylphenyl group etc.) which has the alicyclic hydrocarbon group of these is preferable.
As an aromatic hydrocarbon group by which the hydrogen atom was substituted by the alkoxy group, p-methoxyphenyl group etc. are mentioned.
Examples of the chain hydrocarbon group in which a hydrogen atom is substituted with an aromatic hydrocarbon group include aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group, trityl group, naphthylmethyl group and naphthylethyl group.

Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Examples of the alkylcarbonyl group include acetyl group, propionyl group and butyryl group.
As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned.
As an alkyl carbonyloxy group, a methyl carbonyloxy group, an ethyl carbonyloxy group, a propyl carbonyloxy group, an isopropyl carbonyloxy group, a butyl carbonyloxy group, a sec-butyl carbonyloxy group, a tert-butyl carbonyloxy group, a pentyl carbonyloxy group And hexyl carbonyloxy group, octyl carbonyloxy group and 2-ethylhexyl carbonyloxy group.

The ring formed by combining R ^b4 and R ^b5 together with the sulfur atom to which they are bonded to each other is either monocyclic, polycyclic, aromatic, nonaromatic, saturated or unsaturated It may be a ring of The ring includes a ring having 3 to 18 carbon atoms, preferably a ring having 4 to 18 carbon atoms. The ring containing a sulfur atom includes a 3- to 12-membered ring, preferably a 3- to 7-membered ring, and examples thereof include the following rings.

The ring formed by R ^b9 and R ^b10 together may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. The ring includes a 3- to 12-membered ring, preferably a 3- to 7-membered ring. For example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, a 1,4-oxathiane-4-ium ring and the like can be mentioned.
The ring formed by R ^b11 and R ^b12 together may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. The ring includes a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Examples include oxocycloheptane ring, oxocyclohexane ring, oxonorbornane ring, oxoadamantane ring and the like.

Among the cations (b2-1) to (b2-4), preferred is the cation (b2-1).
The following cations may be mentioned as the cation (b2-1).

The following cations may be mentioned as the cation (b2-2).

The following cations may be mentioned as the cation (b2-3).

The following cations may be mentioned as the cation (b2-4).

As salt (I), the salt of Table 1 is mentioned. For example, in Table 1, the salt (I-1) is a salt composed of the anion represented by the formula (Ia-1) and the cation represented by the formula (b2-c-1), and the salts shown below means.

  Among them, the salt (I) includes salts (I-1) to (I-4), salts (I-9) to (I-12), and salts (I-15) to (I-18). , Salt (I-23) to salt (I-26), salt (I-29) to salt (I-32), salt (I-37) to salt (I-40), salt (I-43) to Salt (I-46), salt (I-51) to salt (I-54), salt (I-57) to salt (I-60), salt (I-65) to salt (I-68), salt (I-71) to salt (I-74), salt (I-79) to salt (I-82), salt (I-85) to salt (I-88), salt (I-93) to salt (I-71) I-96), salt (I-127) to salt (I-130), salt (I-135) to salt (I-138), salt (I-141) to salt (I-148), salt (I) -153) to salt (I-156) and salt (I-159) to salt (I-162) are preferable.

<Method of producing salt (I)>
The salt (I) is produced, for example, by reacting a salt represented by the formula (I-a) with a compound represented by the formula (I-b) in the presence of an acid catalyst in a solvent Can.
(Wherein all symbols have the same meanings as described above)

As an acid catalyst, trifluoromethanesulfonic acid, p-toluenesulfonic acid, etc. are mentioned.
The solvent includes chloroform, dimethylformamide and acetonitrile.
The reaction temperature is usually 20 ° C. to 120 ° C., and the reaction time is usually 0.5 hour to 24 hours.

As a salt represented by Formula (I-a), the salt etc. which are represented below are mentioned and it describes in Unexamined-Japanese-Patent No. 2006-257078, 2009-46479, 2012-193170. It can be manufactured in the manner described.

As a compound represented by Formula (Ib), the compound etc. which are represented by a following formula are mentioned, It can obtain easily from a market.

<Acid Generator>
The acid generator of the present invention is an acid generator containing a salt (I). One type of salt (I) may be contained, or two or more types of salt (I) may be used in combination.
The acid generator of the present invention may contain, in addition to the salt (I), an acid generator known in the field of resist (hereinafter sometimes referred to as “acid generator (B)”). As the acid generator (B), one type may be used alone, or two or more types may be used in combination.

The acid generator (B) may be either nonionic or ionic. Nonionic acid generators include sulfonate esters (eg, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxy ketone, diazonaphthoquinone 4-sulfonate), sulfones (eg, disulfone, Ketosulfone, sulfonyldiazomethane) and the like. As the ionic acid generator, onium salts containing onium cations (for example, diazonium salts, phosphonium salts, sulfonium salts, iodonium salts) are representative. Examples of the anion of the onium salt include a sulfonate anion, a sulfonylimide anion, and a sulfonyl methide anion.
Examples of the acid generator (B) include JP 63-26653, JP 55-164824, JP 62-69263, JP 63-146038, JP 63-163452, and the like. 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. It is possible to use a compound which generates an acid by the radiation described in 4. Moreover, you may use the compound manufactured by the well-known method. The acid generator (B) may be used in combination of two or more.

The acid generator (B) is preferably a fluorine-containing acid generator, and more preferably a salt represented by the formula (B1) (hereinafter referred to as "acid generator (B1)." However, the salt (I) Except).
[In the formula (B1),
Each of Q ^b1 and Q ^b2 independently represents a fluorine atom or a C 1 to C 6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO— The hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents a methyl group which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and is included in the alicyclic hydrocarbon group; CH _2- may be replaced by -O-, -S (O) ₂ -or -CO-.
Z1 ⁺ represents an organic cation. ]

The perfluoroalkyl group represented by Q ^b1 and Q ^b2 includes trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group and Perfluorohexyl group etc. are mentioned.
Each of Q ^b1 and Q ^b2 is preferably independently a fluorine atom or a trifluoromethyl group, and both are more preferably a fluorine atom.

Examples of the divalent saturated hydrocarbon group in L ^b1 include a linear alkanediyl group, a branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and the like. It may be a group formed by combining two or more of the groups.
Specifically, methylene group, ethylene group, propane-1,3-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, dodecane-1,12-diyl group Linear, such as tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group and heptadecane-1,17-diyl group An alkanediyl group;
Ethan-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- Branched alkanediyl groups such as 1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group;
A monocyclic 2 which is a cycloalkanediyl group such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group, etc. Cycloaliphatic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbons such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group and the like And the like.
Examples of the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced by —O— or —CO— include the above-described formulas (b1-1) to (b1-11) And the groups respectively represented by

As an alicyclic hydrocarbon group represented by Y, group represented by Formula (Y1)-Formula (Y11), Formula (Y36)-Formula (Y38) is mentioned.
When -CH _2- contained in the alicyclic hydrocarbon group represented by Y is replaced by -O-, -S (O) ₂ -or -CO-, the number may be one or two or more. Good. As such a group, groups represented by Formula (Y12) to Formula (Y35) and Formula (Y39) to Formula (Y41) can be mentioned.
The alicyclic hydrocarbon group represented by Y is preferably a table represented by any of Formula (Y1) to Formula (Y20), Formula (Y30), Formula (Y31), Formula (Y39) to Formula (Y41). More preferably, it is a group represented by the formula (Y11), the formula (Y15), the formula (Y16), the formula (Y20), the formula (Y30), the formula (Y31), the formula (Y39) or the formula (Y40) And more preferably a group represented by formula (Y11), formula (Y15), formula (Y20), formula (Y30), formula (Y39) or formula (Y40).
When the alicyclic hydrocarbon group represented by Y is a spiro ring containing an oxygen atom, such as Formula (Y28) to Formula (Y35), Formula (Y39) to Formula (Y40), two oxygen atoms The alkanediyl group between them preferably has one or more fluorine atoms. Moreover, it is preferable that the fluorine atom is not substituted by the methylene group adjacent to an oxygen atom among the alkanediyl groups contained in ketal structure.

As a substituent of the methyl group represented by Y, 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,-(- CH ₂ ) _ja -CO-O-R ^b1 group or-(CH ₂ ) _ja -O-CO-R ^b1 group (wherein, R ^b1 is an alkyl group having 1 to 16 carbon atoms, 3 to 16 carbon atoms Represents an alicyclic hydrocarbon group, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof, and -CH _2- contained in the alicyclic hydrocarbon group is -O-, -SO ₂ -Or -CO- may be substituted, and a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a hydroxy group or a fluorine atom, ja is an integer of 0 to 4 And the like.
As a substituent of the alicyclic hydrocarbon group represented by Y, a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms which may be substituted by a hydroxy group, an alicyclic group having 3 to 16 carbon atoms A hydrocarbon group, an alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, a glycidyloxy group,-( CH ₂ ) _ja -CO-O-R ^b1 group or-(CH ₂ ) _ja -O-CO-R ^b1 group (wherein, R ^b1 is an alkyl group having 1 to 16 carbon atoms, 3 to 16 carbon atoms It represents an alicyclic hydrocarbon group, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group combining them, ja represents an integer of 0 to 4, an alkyl group having 1 to 16 carbon atoms, And -C contained in a C3-C16 alicyclic hydrocarbon group ₂ -, -O -, - S (O ) 2 -. Or -CO- in may be replaced), and the like.
As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned.
Examples of the alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a norbornyl group, an adamantyl group and the like.
The alicyclic hydrocarbon group may have a chain hydrocarbon group, and examples thereof include a methylcyclohexyl group and a dimethylcyclohexyl group.
As an aromatic hydrocarbon group, aryl groups, such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, a phenanthryl group, are mentioned, for example.
The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and is an aromatic hydrocarbon group having a chain hydrocarbon group having 1 to 18 carbon atoms (tolyl group Xylyl group, cumenyl group, mesityl group, p-ethylphenyl group, p-tert-butylphenyl group, 2-methyl-6-ethylphenyl group etc.), and alicyclic hydrocarbon groups having 3 to 18 carbon atoms The aromatic hydrocarbon group (p-adamantylphenyl group, p-cyclohexylphenyl group etc.) which it has is preferable.
As the alkyl group, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group And decyl, undecyl, dodecyl and the like.
Examples of the alkyl group substituted by a hydroxy group include hydroxyalkyl groups such as hydroxymethyl group and hydroxyethyl group.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, naphthylmethyl group and naphthylethyl group.
As an alkyl carbonyl group, an acetyl group, a propionyl group, butyryl group etc. are mentioned, for example.

Examples of Y include the following.

When Y is a methyl group and L ^b1 is a divalent linear or branched saturated hydrocarbon group having 1 to 17 carbon atoms, —CH ₂ — adjacent to Y in L ^b1 is —O— Or -CO- is preferred.

Y is preferably a C3-C18 alicyclic hydrocarbon group which may have a substituent, more preferably an adamantyl group which may have a substituent, and the alicyclic carbonization is -CO - - -CH ₂ constituting a hydrogen group or an adamantyl group, - S _{(O) 2} - or -CO- may be replaced with. Y is more preferably an adamantyl group, a hydroxyadamantyl group, an oxoadamantyl group or a group represented by the following.

  As the anion in the salt represented by the formula (B1), an anion represented by any one of the formulas (B1-A-1) to (B1-A-55) [hereinafter referred to as “anion (B1-A according to the formula number -1) etc. Formula (B1-A-1) to formula (B1-A-4), formula (B1-A-9), formula (B1-A-10), formula (B1-A-24) to formula (B1-A-33), formula (B1-A-36) to formula (B1-A-40), formula (B1-A-47) to formula (B1-A-55) Anion is 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 formed, for example, by 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 combination thereof And more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group. ^LA41 is a single bond or an alkanediyl group having 1 to 4 carbon atoms.
Q ^b1 and Q ^b2 represent the same meaning as described above.
Specifically as an anion in the salt represented by Formula (B1), the anion described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned.

Preferable examples of the anion in the salt represented by the formula (B1) include anions represented by the formulas (B1a-1) to (B1a-34).

Among them, Formula (B1a-1) to Formula (B1a-3) and Formula (B1a-7) to Formula (B1a-16), Formula (B1a-18), Formula (B1a-19), Formula (B1a-22) The anion represented by any one of formulas (B1a-34) is preferred.

Examples of Z1 ⁺ in the formula (B1) include the same as the cations in the salt (I).
The acid generator (B1) is a combination of the above-mentioned anion and the above-mentioned organic cation, and these can be optionally combined. As the acid generator (B1), preferably, Formula (B1a-1) to Formula (B1a-3) and Formula (B1a-7) to Formula (B1a-16), Formula (B1a-18), and Formula (B1a-) 19) A combination of an anion represented by any of the formulas (B1a-22) to (B1a-34) and a cation (b2-1) or a cation (b2-3).

Preferred examples of the acid generator (B1) include those represented by the formulas (B1-1) to (B1-48), among which those containing an arylsulfonium cation are preferred, and the formula (B1-1) Formula (B1-3), Formula (B1-5), Formula (B1-7), Formula (B1-11), Formula (B1-14), Formula (B1-20), Formula (B1-26), Those represented by Formula (B1-29), Formula (B1-31) to Formula (B1-48) are particularly preferable.

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

<Resist composition>
The resist composition of the present invention contains an acid generator containing a salt (I) and a resin having an acid labile group (hereinafter sometimes referred to as "resin (A)"). Here, the "acid-labile group" has a leaving group, and the leaving group is released upon contact with an acid, and the constituent unit has a hydrophilic group (for example, a hydroxy group or a carboxy group). It means a group to be converted to a unit.
The resist composition of the present invention preferably contains a quencher (hereinafter sometimes referred to as "quencher (C)") such as a salt that generates an acid having a weaker acidity than the acid generated from the acid generator. And a solvent (hereinafter sometimes referred to as "solvent (E)") are preferably contained.
In the resist composition of the present invention, the content of the acid generator is preferably 1 to 40 parts by mass, more preferably 3 to 35 parts by mass with respect to 100 parts by mass of the resin (A) described later. Part or less.

<Resin (A)>
The resin (A) does not have a halogen atom, and has a structural unit having an acid labile group (hereinafter sometimes referred to as “structural unit (a1)”). The resin (A) preferably further contains a structural unit other than the structural unit (a1). Structural units other than the structural unit (a1) include structural units having no halogen atom and no acid labile group (hereinafter sometimes referred to as “structural unit (s)”), structural units (a1) and Structural units other than the structural unit (s) (for example, structural units having a halogen atom described later (hereinafter sometimes referred to as “structural unit (a4)”), structural units having a non-eliminating hydrocarbon group described later (hereinafter Structural unit (a5)) and other structural units derived from monomers known in the art.

Structural Unit (a1)
The structural unit (a1) is derived from a monomer having an acid labile group (hereinafter sometimes referred to as “monomer (a1)”).
The acid labile group contained in the resin (A) is a group represented by the formula (1) (hereinafter also referred to as a group (1)) and / or a group represented by the formula (2) (hereinafter referred to as a group (2 It is preferred).
[In Formula (1), R ^a1 , R ^a2, and R ^a3 are each independently an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination of these. R ^a1 and R ^a2 bond to each other to form a C 3-20 non-aromatic hydrocarbon ring 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.
* Represents 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, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms Or R ^{a2 '} and R ^a3' combine with each other to form a C 3-20 heterocyclic ring together with the carbon atom to which they are attached and X, and the —CH ₂ contained in the hydrocarbon group and the heterocyclic ring -May be replaced by -O- or -S-.
X represents an oxygen atom or a sulfur atom.
na 'represents 0 or 1;
* Represents a binding site. ]

^Examples of the alkyl group in 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.
The alicyclic hydrocarbon group in R ^a1 , R ^a2 and R ^a3 may be monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and 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) and the like. The carbon number of the alicyclic hydrocarbon group of R ^{a1 to} R ^a3 is preferably 3 to 16.
Examples of the combination of an alkyl group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methyl norbornyl group, a cyclohexylmethyl group, an adamantyl methyl group, an adamantyl dimethyl group, and a norbornyl group. Ethyl group etc. are mentioned.
Preferably, ma is 0 and na is 1.
The following rings may be mentioned as -C (R ^a1 ) (R ^a2 ) (R ^a3 ) when R ^a1 and R ^a2 combine with each other to form a non-aromatic hydrocarbon ring. The non-aromatic hydrocarbon ring preferably has 3 to 12 carbon atoms. * Represents a binding site to -O-.

Examples of the hydrocarbon group in R ^{a1 ′} , R ^{a2 ′} and R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
Examples of the alkyl group and the alicyclic hydrocarbon group include the same groups as the groups listed for R ^a1 , R ^a2 and R ^a3 .
As an aromatic hydrocarbon group, aryl groups, such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, a phenanthryl group, are mentioned.
As the combined group, a group (for example, a cycloalkyl alkyl group) obtained by combining the above-mentioned alkyl group and an alicyclic hydrocarbon group, an aralkyl group such as a benzyl group, or an aromatic hydrocarbon group having an alkyl group (p-methyl) Phenyl group, p-tert-butylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group etc.), alicyclic hydrocarbon group Aromatic hydrocarbon groups (p-cyclohexylphenyl group, p-adamantylphenyl group etc.), aryl-cycloalkyl groups such as phenylcyclohexyl group etc. may be mentioned.
When R ^{a2 '} and R ^a3' combine with each other to form a heterocyclic ring with X and the carbon atom to which they are attached, as -C (R ^{a1 '} ) (R ^a3' ) -X-R ^{a2 '} , And the ring of * Represents a binding site.
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 an alkyl group, ma = 0, and na = 1. As the said group, a tert- butoxycarbonyl group is preferable.
In the formula (1), a group in which R ^a1 and R ^a2 together with the carbon atom to which they are attached form an adamantyl group, R ^a3 is an alkyl group, ma = 0, and na = 1 .
In the formula (1), a group wherein R ^a1 and R ^a2 are each independently an alkyl group, R ^a3 is an adamantyl group, ma is 0, and na is 1.
Specific examples of the group (1) include the following groups. * Represents a binding site.

The following groups may be mentioned as specific examples of the group (2). * Represents 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.

  Among the (meth) acrylic monomers having an acid labile group, those having an alicyclic hydrocarbon group having a carbon number of 5 to 20 are preferably mentioned. If the resin (A) having a structural unit derived from the monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used for the resist composition, the resolution of the resist pattern can be improved.

As a structural unit derived from a (meth) acrylic monomer having a group (1), preferably a structural unit represented by the formula (a1-0) (hereinafter sometimes referred to as a structural unit (a1-0)) A structural unit represented by the formula (a1-1) (hereinafter sometimes referred to as structural unit (a1-1)) or a structural unit represented by the formula (a1-2) (hereinafter referred to as a structural unit (a1-) 2) may be mentioned. These may be used alone or in combination of two or more.
[In the formula (a1-0), the formula (a1-1) and the formula (a1-2),
Each of L ^a01 , L ^a1 and L ^a2 independently represents —O— or * —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents an integer Represents a binding site to -CO-.
Each of R ^a01 , R ^a4 and R ^a5 independently represents a hydrogen atom or a methyl group.
Each of R ^a02 , R ^a03 and R ^a04 independently ^represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination of these.
Each of R ^a6 and R ^a7 independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining these.
m1 represents any integer of 0-14.
n1 represents any integer of 0 to 10.
n1 'represents any integer of 0 to 3. ]

R ^a01 , R ^a4 and R ^a5 are preferably methyl groups.
L ^a01 , L ^a1 and L ^a2 are preferably an oxygen atom or * -O- (CH ₂ ) _k01 -CO-O- (provided that k01 is preferably an integer of 1 to 4 and more preferably Is 1), more preferably an oxygen atom.
As the alkyl group in R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 , an alicyclic hydrocarbon group and a group combining them, the same groups as the groups mentioned in R ^{a1 to} R ^a3 of formula (1) Groups are mentioned.
The carbon number of the alkyl group in R ^a02 , R ^a03 and R ^a04 is preferably 1 to 6, more preferably a methyl group or an ethyl group, and still more preferably a methyl group.
The carbon number of the alkyl group in R ^a6 and R ^a7 is preferably 1 to 6, more preferably a methyl group, an ethyl group or an isopropyl group, and still more preferably an ethyl group or an isopropyl group.
The carbon number of the alicyclic hydrocarbon group of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 is preferably 5 to 12, more preferably 5 to 10.
In the group in which the alkyl group and the alicyclic hydrocarbon group are combined, it is preferable that the total carbon number of the combination of the alkyl group and the alicyclic hydrocarbon group is 18 or less.
^Each of R ^a02 and R ^a03 is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group or an ethyl 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 each independently preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group or an isopropyl group, and still more preferably an ethyl group or an isopropyl 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.

As the structural unit (a1-0), for example, structural units represented by any one of formulas (a1-0-1) to (a1-0-12) and R ^a01 in structural unit (a1-0) can be used. The structural unit by which the corresponding methyl group replaced the hydrogen atom is mentioned, The structural unit represented by either Formula (a1-0-1)-Formula (a1-0-10) is preferable.

As a structural unit (a1-1), the structural unit derived from the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Above all, the methyl group corresponding to R ^a4 in the structural unit represented by any of the formulas (a1-1-1) to (a1-1-4) and the structural unit (a1-1) was replaced with a hydrogen atom The structural unit is preferable, and the structural unit represented by any one of Formula (a1-1-1) to Formula (a1-1-4) is more preferable.

The structural unit (a1-2) corresponds to the structural unit represented by any one of formulas (a1-2-1) to (a1-2-6) and R ^a5 in the structural unit (a1-2) The structural unit which the methyl group replaced with the hydrogen atom is mentioned, and a formula (a1-2-2), a formula (a1-2-5), and a formula (a1-2-6) are preferable.

  When the resin (A) contains the structural unit (a1-0) and / or the structural unit (a1-1) and / or the structural unit (a1-2), the total content of these is the total structure of the resin (A) The amount is usually 10 to 95 mol%, preferably 15 to 90 mol%, more preferably 20 to 85 mol%, still more preferably 25 to 70 mol%, and still more preferably, per unit. It is 30 to 65 mol%.

As a structural unit which has group (2) in structural unit (a1), the structural unit (Hereinafter, it may be called "a structural unit (a1-4).") Represented by Formula (a1-4) is mentioned. .
[In the 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 alkyl carbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl Represents an oxy group or a methacryloyloxy group.
la represents any integer of 0 to 4; When la is 2 or more, a plurality of R ^a33 may be the same as or different from each other.
R ^a34 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a36 may represent a hydrocarbon group having 1 to 20 carbon atoms, R ^a35 and R ^a36 are bonded to each other And form a divalent hydrocarbon group having a carbon number of 2 to 20 together with -C-O- to which they are bound, and the hydrocarbon group and -CH _2- contained in the divalent hydrocarbon group are- It may be replaced by O- or -S-. ]

^Examples of the alkyl group in R ^a32 and R ^a33 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a 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 still more preferably a methyl group.
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 include trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 2,2,2-trifluoroethyl group, 1,1 , 2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3, 3 , 4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group etc. Can be mentioned.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group and hexyloxy group. Especially, a C1-C4 alkoxy group is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further more preferable.
The alkylcarbonyl group includes an acetyl group, a propionyl group and a butyryl group.
As the alkylcarbonyloxy group, an acetyloxy group, a propionyloxy group, a butyryloxy group and the like can be mentioned.
As the hydrocarbon group for R ^a34, R ^a35 and R ^a36, an alkyl group, an alicyclic hydrocarbon group, aromatic hydrocarbon group, and include groups formed by combining these, alkyl groups and alicyclic hydrocarbon groups Examples of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 include the same groups as the alkyl group and the alicyclic hydrocarbon group.
As an aromatic hydrocarbon group, aryl groups, such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, a phenanthryl group, are mentioned.
As the combined group, a group (for example, a cycloalkyl alkyl group) obtained by combining the above-mentioned alkyl group and an alicyclic hydrocarbon group, an aralkyl group such as a benzyl group, or an aromatic hydrocarbon group having an alkyl group (p-methyl) Phenyl group, p-tert-butylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group etc.), alicyclic hydrocarbon group Aromatic hydrocarbon groups (p-cyclohexylphenyl group, p-adamantylphenyl group etc.), aryl-cyclohexyl groups such as phenylcyclohexyl group etc. may be mentioned. In particular, as R ^a36 , 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 Can be mentioned.

In formula (a1-4), a hydrogen atom is preferable as R ^a32 .
As Ra ³³ , an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group and an ethoxy group are more preferable, and a methoxy group is further preferable.
As la, 0 or 1 is preferable, and 0 is more preferable.
R ^a34 is preferably a hydrogen atom.
R ^a35 is preferably an alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group, 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 combination thereof. It is a group to be formed, more preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic aliphatic 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 in R ^a36 are preferably unsubstituted. The aromatic hydrocarbon group in 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 desorbed by contact with an acid (e.g. p- toluenesulfonic acid) to form a hydroxy group.

As a structural unit (a1-4), the structural unit derived from the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Preferably, hydrogen atom corresponding to ^{R a32} in equation (a1-4-1) represented respectively to Formula (a1-4-8) structural units and structural units (a1-4) is replaced by a methyl group structure A unit is mentioned, More preferably, a structural unit represented by a formula (a 1-4-1)-a formula (a 1-4-5), respectively is mentioned.
When resin (A) contains a structural unit (a1-4), it is preferable that the content rate is 10-95 mol% with respect to the sum total of all the structural units of resin (A), and 15-90. It is more preferable that it is mol%, It is further more preferable that it is 20-85 mol%, It is further more preferable that it is 20-70 mol%, It is especially preferable that it is 20-60 mol%.

As a structural unit derived from a (meth) acrylic monomer having a group (2), a structural unit represented by formula (a1-5) (hereinafter sometimes referred to as "structural unit (a1-5)") is also mentioned. Be
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 - represents, h3 represents an integer of 1 to 4, * represents a binding site with L ^51.
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ each independently represent -O- or -S-.
s1 represents any integer of 1 to 3.
s1 'represents any integer of 0 to 3.

As a halogen atom, a fluorine atom and a chlorine atom are mentioned, and a fluorine atom is preferable.
As a C1-C6 alkyl group which may have a halogen atom, 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 fluoromethyl group and a trifluoro A methyl group is mentioned.
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 be -O- and the other be -S-.
As s1, 1 is preferable.
s1 'is preferably an integer of 0 to 2.
Z ^a1 is preferably a single bond or * -CH ₂ -CO-O-.

As a structural unit (a1-5), the structural unit derived from the monomer described in Unexamined-Japanese-Patent No. 2010-61117 is mentioned, for example. Among them, structural units represented by Formula (a1-5-1) to Formula (a1-5-4) are preferable, and are represented by Formula (a1-5-1) or Formula (a1-5-2). Structural units are more preferred.
When resin (A) contains a structural unit (a1-5), 1-50 mol% is preferable with respect to the total structural unit of resin (A), as for the content rate, 3-45 mol% is more preferable. 5 to 40 mol% is more preferable, and 5 to 30 mol% is even more preferable.

Moreover, the following structural units are also mentioned as a structural unit (a1).
When the resin (A) contains structural units such as the above (a1-3-1) to (a1-3-7), the content is 10 to 10 parts of the total structural units of the resin (A). 95 mol% is preferable, 15 to 90 mol% is more preferable, 20 to 85 mol% is more preferable, 20 to 70 mol% is still more preferable, and 20 to 60 mol% is particularly preferable.

<Structural unit (s)>
The structural unit (s) is derived from a monomer having no halogen atom and no acid labile group (hereinafter sometimes referred to as "monomer (s)"). As the monomer leading to the structural unit (s), monomers 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. Structural unit having a hydroxy group and having no acid labile group (hereinafter sometimes referred to as “structural unit (a2)”) and / or a structure having a lactone ring and having no acid labile group If a resin having a unit (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 the adhesion to the substrate can be improved.

Structural unit (a2)
The hydroxy group possessed by the structural unit (a2) may be either an alcoholic hydroxy group or a phenolic hydroxy group.
When a resist pattern is produced from the resist composition of the present invention, as a structural unit (a2) when using a high energy beam such as a KrF excimer laser (248 nm), an electron beam or EUV (super ultraviolet light) as an exposure light source It is preferable to use a structural unit (a2) having a phenolic hydroxy group. When using an ArF excimer laser (193 nm) or the like, a structural unit (a2) having an alcoholic hydroxy group is preferable as the structural unit (a2), and it is more preferable to use a structural unit (a2-1) described later preferable. As a structural unit (a2), 1 type may be included independently and 2 or more types may be included.

Examples of the structural unit having a phenolic hydroxy group in the structural unit (a2) include structural units represented by Formula (a2-A) (hereinafter sometimes referred to as “structural unit (a2-A)”).
[In the 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 is 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 alkyl carbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl Represents an oxy group or a methacryloyloxy group.
A ^a50 represents a single bond or ^{* -X a51 - (A a52 -X} a52) nb - represents, * represents a binding site to the carbon atom to which -R ^a50 binds.
A ^a52 each independently represents a C 1 to ^C 6 alkanediyl group.
X ^a51 and X ^a52 each independently represent -O-, ^-CO -O- or -O-CO-.
nb represents 0 or 1.
mb represents any integer from 0 to 4; When mb is an integer of 2 or more, a plurality of R a ⁵¹ may be the same as or different from each other. ]

^Examples of the halogen atom in R ^a50 include a fluorine atom, a chlorine atom and a bromine atom.
As a C1-C6 alkyl group which may have a halogen atom in R ^a50 , a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, 1,1,2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,2, 3,3,4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group and perfluoro group A hexyl group is mentioned.
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 still more preferably a hydrogen atom or a methyl group.
^Examples of the alkyl group in Ra ⁵¹ 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.
^Examples of the alkoxy group in 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. A C1-C4 alkoxy group is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further more preferable.
^Examples of the alkylcarbonyl group in R ^a51 include an acetyl group, a propionyl group and a butyryl group.
^Examples of the alkylcarbonyloxy group in R ^a51 include an acetyloxy group, a propionyloxy group and a butyryloxy group.
Ra ⁵¹ is preferably a methyl group.

* -X ^a51- (A ^a52- X ^a52 ) _nb -as * ^-O- , *-CO-O-, * ^-O - ^CO- , *-CO-O-A a ^52- CO-O-, * -O-CO-A ^a52 -O-, * -O-A ^a52 -CO-O-, * -CO-O-A ^a52 -O- ^CO- , * -O-CO-A ^a52 -O-CO -, Can be mentioned. Among them, * -CO-O-, * -CO-O- ^Aa52- CO-O- or * -O- ^Aa52- CO-O- is preferable.
As an alkanediyl group, a 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, butane-1,3-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 etc. are mentioned.
A ^a52 is preferably a methylene group or an ethylene group.

A ^a50 is preferably a single bond, * -CO-O- or * -CO-O-a ^a52- CO-O-, and a single bond, * -CO-O- or * -CO-O-CH It is more preferable that it is _2- CO-O-, and it is further preferable that it is a single bond or * -CO-O-.

As mb, 0, 1 or 2 is preferable, 0 or 1 is more preferable, and 0 is particularly preferable.
The hydroxy group is preferably bonded to the o- or p-position of the benzene ring, and more preferably to the p-position.

As a structural unit (a2-A), the structural unit derived from the monomer described in Unexamined-Japanese-Patent No. 2010-204634 and 2012-12577 is mentioned.
As the structural unit (a2-A), structural units represented by formulas (a2-2-1) to (a2-2-4) and formulas (a2-2-1) to (a2-2-) The structural unit by which the methyl group corresponded to ^Ra50 in a structural unit (a2-A) in structural unit represented by 4) was ^substituted by the hydrogen atom is mentioned. The structural unit (a2-A) is represented by the structural unit represented by the formula (a2-2-1), the structural unit represented by the formula (a2-2-3) and the formula (a2-2-1) In the structural unit represented by the general formula (a2-2-3), it is preferable that the structural unit is a structural unit in which a methyl group corresponding to R ^a50 in the structural unit (a2-A) is replaced with a hydrogen atom.
The content of the structural unit (a2-A) in the case where the structural unit (a2-A) is contained in the resin (A) is preferably 5 to 80 mol%, more preferably 5 to 80 mol%, based on all structural units. It is 10 to 70 mol%, more preferably 15 to 65 mol%, still more preferably 20 to 65 mol%.
The structural unit (a2-A) can be contained in the resin (A) by, for example, polymerizing using the structural unit (a1-4) described later and then treating with an acid such as p-toluenesulfonic acid. . In addition, the structural unit (a2-A) can be contained in the resin (A) by treating with an alkali such as tetramethyl ammonium hydroxide after polymerization using acetoxystyrene or the like.

Examples of the structural unit having an alcoholic hydroxy group in the structural unit (a2) include structural units 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 any integer of 1 to 7; * Represents a binding site to -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 any integer of 0 to 10;

In formula (a2-1), L ^a3 is preferably -O- or -O- (CH ₂ ) _f1 -CO-O- (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.

As a structural unit (a2-1), the structural unit derived from the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. The structural unit represented by any one of Formula (a2-1-1) to Formula (a2-1-6) is preferable, and any of Formula (a2-1-1) to Formula (a2-1-4) The structural unit represented is more preferable, and the structural unit represented by Formula (a2-1-1) or Formula (a2-1-3) is more preferable.
When the resin (A) contains a structural unit (a2-1), the content is usually 1 to 45 mol%, preferably 1 to 40 mol%, based on all structural units of the resin (A). More preferably, it is 1 to 35 mol%, more preferably 2 to 20 mol%, and still more preferably 2 to 10 mol%.

Structural unit (a3)
The lactone ring possessed by the structural unit (a3) may be a monocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ring, or a δ-valerolactone ring, and a fused ring of a monocyclic lactone ring and another ring May be. Preferably, 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)) can be mentioned.

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 may be contained.
[In the formula (a3-1), the formula (a3-2), the formula (a3-3) and the formula (a3-4),
L ^a4 , L ^a5 and L ^a6 are each independently represented by -O- or * -O- (CH ₂ ) _k3 -CO-O- (k3 represents an integer of 1 to 7). Represents a group.
L ^a7 is -O-, * -O-L ^a8 -O-, * -O-L ^a8 -CO-O-, * -O-L ^a8 -CO-O-L ^a9 -CO-O- or * -O- ^La8- O-CO- ^La9- O-.
Each of L ^a8 and L ^a9 independently represents an alkanediyl group having 1 to 6 carbon atoms.
* Represents a bonding site to a carbonyl group.
Each of R ^a18 , R ^a19 and R ^a20 independently represents a hydrogen atom or a methyl group.
R ^a24 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
Each of R ^a22 , R ^a23 and R ^a25 independently represents a carboxy group, a cyano group or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents any integer of 0 to 5;
q1 represents any integer of 0 to 3;
r1 represents any integer of 0 to 3;
w1 represents any integer of 0 to 8;
When p1, q1, r1 and / or w1 are 2 or more, the plurality of R ^a21 , R ^a22 , R ^a23 and / or R ^a25 may be identical to or different from each other. ]

As an aliphatic hydrocarbon group in R ^a21 , R ^a22 , R ^a23 and R ^a25 , alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group and tert-butyl group may be mentioned. Be
As a halogen atom in R ^a24 , a fluorine atom, a chlorine atom, a bromine atom and an iodine atom can be mentioned.
^Examples of the alkyl group for 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 the like, and more preferably a methyl group or an ethyl group.
Examples of the alkyl group having a halogen atom in R ^a24 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group, perfluoro Examples thereof include hexyl group, trichloromethyl group, tribromomethyl group and triiodomethyl group.
As an alkanediyl group in L ^a8 and L ^a9 , a 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, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, 4-diyl group and 2-methyl butane-1,4-diyl group etc. are mentioned.

In formulas (a3-1) to (a3-3), each of L ^{a4 to} L ^a6 independently is preferably _{k3 in} —O— or * —O— (CH ₂ ) _k3 —CO—O—. group but is any integer of 1 to 4, more preferably -O- _{and, * - O-CH 2 -CO} -O-, more preferably an oxygen atom.
R ^{a18 to} R ^a21 are preferably methyl groups.
Each of R ^a22 and R ^a23 is preferably independently a carboxy group, a cyano group or a methyl group.
Each of p1, q1 and r1 is independently preferably an 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 still more preferably a hydrogen atom or a methyl group It is.
Ra ²⁵ is preferably a carboxy group, a cyano group or a methyl group.
L ^a7 is preferably -O- or ^{* -O-L} a8 -CO-O-, more preferably an _{-O -, - O-CH 2} -CO-O- or _-O-C 2 _{H 4} - CO-O-.
w1 is preferably an integer of 0 to 2, more preferably 0 or 1.
In particular, the formula (a3-4) is preferably a formula (a3-4) ′.
(Wherein, R ^a24 and L ^a7 represent the same meaning as described above)

As the structural unit (a3), a structure described in JP-A-2010-204646, a monomer described in JP-A-2000-122294, and a structure derived from a monomer described in JP-A-2012-41274. Unit is mentioned. As the structural unit (a3), a formula (a3-1-1), a formula (a3-1-2), a formula (a3-2-1), a formula (a3-2-2) and a formula (a3-3-3) 1) The structural unit represented by any one of Formula (a3-3-2) and Formula (a3-4-1) to Formula (a3-4-12), and the structural unit represented by Formula (a3-1) A structural unit in which a methyl group corresponding to R ^a18 , R ^a19 , R ^a20 and R ^a24 in the formula (a3-4) is replaced with a hydrogen atom is preferable.

When the resin (A) contains the structural unit (a3), the total content is usually 5 to 70 mol%, preferably 10 to 65 mol%, relative to the total structural units of the resin (A). And more preferably 10 to 60 mol%.
Moreover, 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 relative to all structural units of the resin (A) The amount is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, and still more preferably 10 to 50 mol%.

Structural unit (a4)
Examples of the structural unit (a4) include the following structural units.
[In the formula (a4),
R ⁴¹ represents a hydrogen atom or a methyl group.
R ⁴² represents a saturated hydrocarbon group having a fluorine atom of 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O— or —CO. ]
The saturated hydrocarbon group represented by R ⁴² includes a chain saturated hydrocarbon group, a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and a group formed by combining these.

As a chain saturated hydrocarbon group, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, pentadecyl group, hexadecyl group, heptadecyl group and octadecyl group Can be mentioned. Examples of monocyclic or polycyclic alicyclic saturated hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl; decahydronaphthyl, adamantyl, norbornyl and the following: Polycyclic alicyclic saturated hydrocarbon groups, such as group (* represents a coupling | bonding site | part) etc. are mentioned.
Examples of the group formed by the combination include a group formed by combining one or more alkyl groups or one or more alkanediyl groups with one or more alicyclic saturated hydrocarbon groups, and -alkanediyl groups -Alicyclic saturated hydrocarbon group,-alicyclic saturated hydrocarbon group-alkyl group,-alkanediyl group-alicyclic saturated hydrocarbon group-alkyl group, etc. may be mentioned.

As the structural unit (a4), at least one selected from the group consisting of formula (a4-0), formula (a4-1), formula (a4-2), formula (a4-3) and formula (a4-4) The structural unit represented by 1 is mentioned.
[In the formula (a4-0),
R ⁵⁴ represents a hydrogen atom or a methyl group.
L ^4a represents a single bond or an alkanediyl group having 1 to 4 carbon atoms.
L ^3a represents a C 1 to C 8 perfluoroalkanediyl group or a C ³ to C 12 perfluorocycloalkanediyl group.
R ⁶⁴ represents a hydrogen atom or a fluorine atom. ]

As the alkanediyl group in L ^4a, a linear alkanediyl group such as methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, ethane-1,1-diyl group, Branched alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group Be
As a perfluoroalkanediyl group in L ^3a , a difluoromethylene group, a perfluoroethylene group, a perfluoroethyl fluoromethylene group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group, a perfluoropropane-2,2 -Diyl group, perfluorobutane-1,4-diyl group, perfluorobutane-2,2-diyl group, perfluorobutane-1,2-diyl group, perfluoropentane-1,5-diyl group, perfluoropentane-2,2 -Diyl group, perfluoropentane-3,3-diyl group, perfluorohexane-1,6-diyl group, perfluorohexane-2,2-diyl group, perfluorohexane-3,3-diyl group, perfluoroheptane-1,7 -Diyl group, perfluoro hep 2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane-2,2-diyl group, perfluorocarbon The octane-3, 3-diyl group, the perfluoro octane-4, 4-diyl group etc. are mentioned.
^Examples of the perfluorocycloalkanediyl group in L ^3a include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, a perfluoroadamantanediyl group and the like.

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

Examples of the structural unit (a4-0) include structural units shown below and structural units in which a methyl group corresponding to R ⁵⁴ in the structural unit (a4-0) in the following structural units is replaced with a hydrogen atom.

[In the 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 is replaced by -O- or -CO- May be
A ^a41 represents a alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a group represented by the formula (a-g1). However, at least one of A ^a41 and R ^a42 has a halogen atom (preferably a fluorine atom) as a substituent.
[In the formula (a-g1),
s represents 0 or 1;
A ^a42 and A ^a44 each independently represent a C1-C5 divalent saturated hydrocarbon group which may have a substituent.
A ^a43 represents a single bond or a divalent saturated hydrocarbon group of 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 carbon number of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less. ]
* Is a binding site, and * on the right is a binding site to -O-CO-Ra ⁴² . ]

^Examples of the saturated hydrocarbon group for R ^a42 include a chain hydrocarbon group, a monocyclic or polycyclic alicyclic hydrocarbon group, and a group formed by combining these.

As a chain hydrocarbon group, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, pentadecyl group, hexadecyl group, heptadecyl group and octadecyl group are mentioned. It can be mentioned. Examples of monocyclic or polycyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups Polycyclic alicyclic hydrocarbon groups such as (* represents a bond) are mentioned.
Examples of the group formed by the combination include a group formed by combining one or more alkyl groups or one or more alkanediyl groups and one or more alicyclic hydrocarbon groups, and -alkanediyl groups- Alicyclic hydrocarbon group, -alicyclic hydrocarbon group-alkyl group, -alkanediyl group-alicyclic hydrocarbon group-alkyl group, etc. may be mentioned.

^Examples of the substituent which may be possessed by R ^a42 include at least one selected from the group consisting of a halogen atom and a group represented by the formula (a-g3). The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a fluorine atom.
[In the formula (a-g3),
X ^a43 represents an oxygen atom, a carbonyl group, * ^-O -CO- or * -CO-O- (* represents a binding site to R ^a42 ).
A ^a45 represents a saturated hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
* Represents a binding site. ]
However, in R ^a42 -X ^a43 -A ^a45 , when R ^a42 does not have a halogen atom, A ^a45 represents a saturated hydrocarbon group having 1 to 17 carbon atoms having at least one halogen atom.

As a saturated hydrocarbon group in A ^a45 , methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, pentadecyl group, hexadecyl group, heptadecyl group and octadecyl group Alkyl groups such as groups;
Monocyclic alicyclic hydrocarbon groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; and decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* represents a bond) Etc.) and the like.

R ^a42 is preferably a saturated hydrocarbon group which may have a halogen atom, more preferably an alkyl group having a halogen atom and / or a saturated hydrocarbon group having a group represented by the formula (a-g3).
When R ^a42 is a saturated hydrocarbon group having a halogen atom, it is preferably a saturated hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, and still more preferably having a carbon number of 1 to 4 It is a perfluoroalkyl group of 6, particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. Examples of the perfluoroalkyl group include perfluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorohexyl group, perfluoroheptyl group and perfluorooctyl group. As a perfluorocycloalkyl group, a perfluorocyclohexyl group etc. are mentioned.
When R ^a42 is a saturated hydrocarbon group having a group represented by formula (a-g3), the total carbon number of R ^a42 including the number of carbons contained in the group represented by formula (a-g3) The number is preferably 15 or less, more preferably 12 or less. When it has a group represented by formula (a-g3) as a substituent, the number is preferably one.

When R ^a42 is a saturated hydrocarbon group having a group represented by formula (a-g3), R ^a42 is more preferably a group represented by formula (a-g2).
[In the formula (a-g2),
A ^a46 represents a ^divalent C 1 to ^C 17 saturated hydrocarbon group which may have a halogen atom.
X ^a44 represents * ^-O -CO- or * -CO-O- (* represents a binding site to A ^a46 ).
A ^a47 represents a saturated hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
However, the total carbon number 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.
* Represents a bonding site to a carbonyl group. ]

1-6 are preferable and, as for carbon number of the saturated hydrocarbon group of A ^a46 , 1-3 are more preferable.
The carbon number of the saturated hydrocarbon group of A ^a47 is preferably 4 to 15, more preferably 5 to 12, and A ^a47 is more preferably a cyclohexyl group or an adamantyl group.

The preferred structure of the group represented by formula (a-g2) is the following structure (* is a bonding site to a carbonyl group).

As an alkanediyl group in A ^a41 , a methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group Alkane-1, 2-diyl, butane-1, 3-diyl, 2-methylpropane-1, 2-diyl, 1-methylbutane-1, 4-diyl; Examples thereof include branched alkanediyl groups such as 2-methylbutane-1,4-diyl group.
As a substituent in the alkanediyl group which A ^a41 represents, a hydroxy group, a C1-C6 alkoxy group, etc. are mentioned.
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 still more preferably an ethylene group.

As a divalent saturated hydrocarbon group represented by A ^a42 , A ^a43 and A ^{a44 in} the group represented by the formula (a-g1), a linear or branched alkanediyl group and a monocyclic divalent alicyclic alicyclic group Examples thereof include saturated hydrocarbon groups, and divalent saturated hydrocarbon groups formed by combining an alkanediyl group and a divalent alicyclic saturated hydrocarbon group. Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, 1-methylpropane-1,3-diyl group, Examples include 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group and the like.
As a substituent of the bivalent saturated hydrocarbon group which A ^a42 , A ^a43, and A ^a44 represent, a hydroxy group, a C1-C6 alkoxy group, etc. are mentioned.
s is preferably 0.

^{Examples of the} group in which X ^a42 is —O—, ^—CO— , ^—CO —O— or —O—CO— in the group represented by the formula (a-g1) include the following groups. In the following exemplification, * and ** each represent a binding site, and ** is a binding site to -O-CO-Ra ⁴² .

As the structural unit represented by the formula (a4-1), a methyl group corresponding to R ^a41 in the structural unit represented by the formula (a4-1) in the following structural units and the following structural units is a hydrogen atom The structural unit replaced is mentioned.

As a structural unit represented by Formula (a4-1), the structural unit represented by Formula (a4-2) is preferable.
[In the formula (a4-2),
R ^f5 represents a hydrogen atom or a methyl group.
L ⁴⁴ represents a C 1 to C 6 alkanediyl group, and —CH ₂ — contained in the alkanediyl group may be replaced by —O— or —CO—.
R ^f6 represents a saturated hydrocarbon group having a fluorine atom of 1 to 20 carbon atoms.
However, the upper limit of the total carbon number of L ⁴⁴ and R f ⁶ is 21. ]
Examples of the C ^1-4 alkanediyl group of L ⁴⁴ include the same groups as those exemplified for A ^a41 .
Examples of the saturated hydrocarbon group for R ^f6 include the same groups as those exemplified for R ^a42 .
The alkanediyl group having 1 to 6 carbon atoms in L ^44, preferably alkanediyl group having 2 to 4 carbon atoms, and more preferably an ethylene group.

As a structural unit represented by Formula (a4-2), the structural unit respectively represented by Formula (a4-1-1)-Formula (a4-1-11) is mentioned, for example. A structural unit in which a methyl group corresponding to R ^f5 in the structural unit (a4-2) is replaced with a hydrogen atom is also mentioned as a structural unit represented by the formula (a4-2).

[In the formula (a4-3),
R ^f7 represents a hydrogen atom or a methyl group.
And L ⁵ represents an alkanediyl group having 1 to 6 carbon atoms.
A ^f13 represents a divalent C 1 to C 18 saturated hydrocarbon group which may have a fluorine atom.
X ^f12 represents * -O-CO- or * -CO-O- (* represents a binding site to A ^f13 ).
A ^f14 represents a C 1 to C 17 saturated hydrocarbon group 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 carbon number of L ⁵ , A ^f13 and A ^f14 is 20. ]

^Examples of the alkanediyl group in L ⁵ include the same groups as those exemplified for the alkanediyl group of A ^a41 .
As the divalent saturated hydrocarbon group which may have a fluorine atom in A ^{f13, a} divalent chain saturated hydrocarbon group which may preferably have a fluorine atom and a fluorine atom are preferable. It is also a divalent alicyclic saturated hydrocarbon group, more preferably a perfluoroalkanediyl group.
As a divalent chain saturated hydrocarbon group which may have a fluorine atom, alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group and pentanediyl group; difluoromethylene group, perfluoroethylene group, Perfluoropropanediyl group, perfluorobutanediyl group, and perfluoroalkanediyl group such as perfluoropentanediyl group, etc. may be mentioned.
The divalent alicyclic saturated hydrocarbon group which may have a fluorine atom may be either monocyclic or polycyclic. Examples of the monocyclic group include a cyclohexanediyl group and a perfluorocyclohexanediyl group. Examples of the polycyclic group include an adamantanediyl group, a norbornanediyl group, and a perfluoroadamantanediyl group.
Examples of the saturated hydrocarbon group of A ^{f14 and} the saturated hydrocarbon group which may have a fluorine atom include the same groups as those exemplified for R ^a42 . Among them, trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, butyl group, perfluoropentyl group, Fluorination of 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, heptyl group, perfluoroheptyl group, octyl group and perfluorooctyl group etc. Alkyl group, cyclopropylmethyl group, cyclopropyl group, cyclobutylmethyl group, cyclopentyl group, cyclohexyl group, Fluorocyclohexyl group, adamantyl group, adamantylmethyl group, adamantyl dimethyl group, norbornyl group, norbornylmethyl group, perfluoro adamantyl group, a perfluoroalkyl adamantylmethyl group and the like are preferable.

In formula (a4-3), L ⁵ is preferably an ethylene group.
The divalent saturated hydrocarbon group of A ^f13 is preferably a group containing a chain saturated hydrocarbon group having 1 to 6 carbon atoms and an alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, and having 2 to 3 carbon atoms Chain saturated hydrocarbon groups are more preferred.
The saturated hydrocarbon group of A ^f14 is preferably a group containing a chain saturated hydrocarbon group having 3 to 12 carbon atoms and a cycloaliphatic saturated hydrocarbon group having 3 to 12 carbon atoms, and the chain saturated group having 3 to 10 carbon atoms A group containing a hydrocarbon group and an alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms is more preferable. Among them, A ^f14 is preferably a group containing an alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group and an adamantyl group .

As a structural unit represented by Formula (a4-3), the structural unit respectively represented by Formula (a4-1-1)-Formula (a4-1-11) is mentioned, for example. A structural unit in which a methyl group corresponding to R ^f7 in the structural unit (a4-3) is replaced with a hydrogen atom is also mentioned as a structural unit represented by the formula (a4-3).

As a structural unit (a4), the structural unit represented by Formula (a4-4) is also mentioned.
[In the formula (a4-4),
R ^f21 represents a hydrogen atom or a methyl group.
A ^f21 _{is, - (CH 2) j1 -} , - (CH 2) j2 -O- (CH 2) j3 - or _{- (CH 2) j4 -CO-} O- (CH 2) j5 - represents a.
Each of j1 to j5 independently represents an integer of 1 to 6.
R ^f22 represents a C1-C10 saturated hydrocarbon group having a fluorine atom. ]

Saturated hydrocarbon groups R ^f22 include the same as the saturated hydrocarbon group represented by R ^a42. R ^{f 22} is preferably a ^C 1-10 alkyl group having a fluorine atom or a C 1-10 alicyclic saturated hydrocarbon group having a fluorine atom, and the C 1-10 alkyl group having a fluorine atom is preferred. More preferably, a C1-C6 alkyl group which has a fluorine atom is still more preferable.

In formula (a4-4), as A ^f21 ,-(CH ₂ ) _j1 -is preferable, an ethylene group or a methylene group is more preferable, and a methylene group is further preferable.

As the structural unit represented by the formula (a4-4), for example, in the structural units represented by the following structural units and the following formula, a methyl group corresponding to R ^f21 in the structural unit (a4-4) is hydrogen Structural units in which atoms are replaced can be mentioned.

  When resin (A) has a structural unit (a4), the content is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, with respect to the total structural units of resin (A). -10 mol% is more preferable.

Structural unit (a5)
As a non-elimination hydrocarbon group which a structural unit (a5) has, the group which has a linear, branched or cyclic hydrocarbon group is mentioned. Among them, the structural unit (a5) is preferably a group having an alicyclic hydrocarbon group.
As a structural unit (a5), the structural unit represented by Formula (a5-1) is mentioned, for example.
[In the 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 by -O- or -CO- . ]

The alicyclic hydrocarbon group for R ⁵² may be monocyclic or polycyclic. As a monocyclic alicyclic hydrocarbon group, a cyclopropyl group, cyclobutyl group, a cyclopentyl group, and a cyclohexyl group are mentioned, for example. Examples of the polycyclic alicyclic hydrocarbon group include an adamantyl group and a norbornyl group.
Examples of the aliphatic hydrocarbon group having 1 to 8 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group and 2 And-an alkyl group such as ethylhexyl group.
As an alicyclic hydrocarbon group which has a substituent, 3-hydroxy adamantyl group, 3-methyl adamantyl group, etc. are mentioned.
R ⁵² is preferably a non-substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.
Examples of the divalent saturated hydrocarbon group for L ⁵⁵ include a divalent chain saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, preferably a divalent chain saturated hydrocarbon group .
Examples of the divalent chain saturated hydrocarbon group include alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group and pentanediyl group.
The divalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. As a monocyclic alicyclic saturated hydrocarbon group, cycloalkane diyl groups, such as a cyclopentane diyl group and a cyclohexane diyl group, are mentioned. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantanediyl group and a norbornanediyl group.

Examples of the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ⁵⁵ is replaced by —O— or —CO— include, for example, a group represented by Formula (L1-1) to Formula (L1-4) The group represented is mentioned. In the following formula, * represents a binding site to an oxygen atom.
In formula (L1-1),
X ^x1 represents * -O-CO- or * -CO-O- (* represents a binding site to 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 carbon number of L ^x1 and L ^x2 is 16 or less.
In formula (L1-2),
L ^{x 3} represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms.
L ^{x 4} represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
However, the total carbon number of L ^x3 and L ^x4 is 17 or less.
In formula (L1-3),
L ^{x 5} represents a C1-C15 divalent aliphatic saturated hydrocarbon group.
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 carbon number of L ^x5 , L ^x6 and L ^x7 is 15 or less.
In the formula (L1-4),
L ^{x 8} and L ^{x 9 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 carbon number of L ^x8 , L ^x9 and W ^x1 is 15 or less.
L ^x1 is preferably a C 1 to C 8 divalent aliphatic saturated hydrocarbon group, 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 ^{x 3} is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^{x 4} is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^{x 5} is preferably a C 1 to C 8 divalent aliphatic saturated hydrocarbon group, more preferably a methylene group or an ethylene group.
L ^{x 6} 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 ^{x 7} is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^{x 8} 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 ^{x 9} 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.

As a group represented by Formula (L1-1), the bivalent group shown below is mentioned, for example.

As a group represented by Formula (L1-2), the bivalent group shown below is mentioned, for example.

As a group represented by Formula (L1-3), the bivalent group shown below is mentioned, for example.

As a group represented by Formula (L1-4), the bivalent group shown below is mentioned, for example.
L ⁵⁵ is preferably a single bond or a group represented by formula (L1-1).

The structural unit (a5-1), a methyl group corresponding to R ⁵¹ may be mentioned a structural unit replacing a hydrogen atom in the structural units in the structural units and the following structural units shown below (a5-1).

When resin (A) has a structural unit (a5), 1-30 mol% is preferable with respect to the total structural unit of resin (A), and, as for the content rate, 2-20 mol% is more preferable, and 3 -15 mol% is more preferable.

<Structural unit (II)>
The resin (A) may further contain a structural unit (hereinafter, sometimes referred to as “structural unit (II)”) which is decomposed by exposure to generate an acid. Specific examples thereof include structural units described in JP-A-2016-79235, and structural units having a sulfonate group or carboxylate group and an organic cation in the side chain or structural units having a sulfonio group and an organic anion in the side chain. Is preferred.

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 the formula (II-2-A ′).
[In the formula (II-2-A '),
X ^III3 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group may be substituted by -O-, -S- or -CO- Preferably, the 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.
As the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^III3, the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^a8 The same thing is mentioned.
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, and a pentane-1,5-diyl group. Hexane-1,6-diyl, ethane-1,1-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-2,2-diyl, pentane-2, 4-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group, etc. It can be mentioned.

As a C1-C18 bivalent saturated hydrocarbon group represented by X ^III3 , a linear or branched alkanediyl group and a monocyclic or polycyclic bivalent alicyclic saturated hydrocarbon group are mentioned. Or a combination of these.
Specifically, 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 , Linear alkanediyl groups such as dodecane-1,12-diyl group; butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group And branched alkanediyl groups such as pentane-1,4-diyl group and 2-methylbutane-1,4-diyl group; cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1 , 4-diyl group, Cycloalkanediyl groups such as rooctane-1,5-diyl group; norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group And bivalent polycyclic alicyclic saturated hydrocarbon groups and the like.

As -CH _2- contained in a saturated hydrocarbon group is replaced by -O-, -S- or -CO-, for example, divalent groups represented by formula (X1) to formula (X53) It can be mentioned. However, -CH ₂ contained in a saturated hydrocarbon group - is, -O -, - number of carbon atoms before replacing with S- or -CO- is respectively 17 or less. In the following formula, * represents a binding site to A ^x1 .

X ³ represents a divalent C 1-16 saturated hydrocarbon group.
X ⁴ represents a divalent C 1-15 saturated hydrocarbon group.
X ⁵ represents a divalent C 1-13 saturated hydrocarbon group.
X ⁶ represents a divalent C 1-14 saturated hydrocarbon group.
X ⁷ represents a trivalent, 1 to 14 carbon saturated hydrocarbon group.
X ⁸ represents a divalent C 1-13 saturated hydrocarbon group.

As the organic cation represented by ZA ⁺ , those similar to the cations in the salt (I) can be mentioned.

The structural unit represented by the formula (II-2-A ′) is preferably a structural unit represented by the formula (II-2-A).
[In the formula (II-2-A), R ^III3 , X ^III3 and ZA ⁺ represent the same meaning as described above.
z2A represents any 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 more, plural R ^III2 and R ^III4 are identical to each other It may also be different.
Each of Q ^a and Q ^b independently represents a fluorine atom or a C 1 to C 6 perfluoroalkyl group. ]
The ^{R III2,} R III4, ^Q perfluoroalkyl group having 1 to 6 carbon atoms represented by ^a and ^{Q b,} include those similar to the perfluoroalkyl group having 1 to 6 carbon atoms represented by the aforementioned ^{Q b1} .

The structural unit represented by the formula (II-2-A) is preferably a structural unit represented by the formula (II-2-A-1).
[In the formula (II-2-A-1),
R ^III2 , R ^III3 , R ^III4 , Q ^a , Q ^b , z2A and ZA ⁺ have the same meaning as described above.
R ^III5 represents a saturated hydrocarbon group having 1 to 12 carbon atoms.
X ^I2 represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group may be replaced by -O-, -S- or -CO- Preferably, the hydrogen atom contained in the saturated hydrocarbon group may be substituted by a halogen atom or a hydroxy group. ]
As a C1- ^C12 saturated hydrocarbon group represented by R ^III5 , 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, Examples thereof include linear or branched alkyl groups such as heptyl group, octyl group, nonyl group, decyl group, undecyl group and dodecyl group.
As a bivalent saturated hydrocarbon group represented by X ^I2 , the thing similar to the bivalent saturated hydrocarbon group represented by X ^III3 is mentioned.

As a structural unit represented by Formula (II-2-A-1), the structural unit represented by Formula (II-2-A-2) is preferable.
[In the formula (II-2-A-2), R ^III3 , R ^III5 and ZA ⁺ represent the same meaning as described above.
m and n each independently represent 1 or 2; ]

Examples of the structural unit represented by the formula (II-2-A ′) include the following structural units and the 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 the 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 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 And a hydrogen atom contained in the chain hydrocarbon group is 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 And the hydrogen atom contained in the alicyclic hydrocarbon group may be a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkyl carbonyl group having 2 to 4 carbon atoms, or a glycidyloxy group And the hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group or an alkoxy group having 1 to 12 carbon atoms. R ^II2 and R ^II3 may combine with each other to form a ring together with the sulfur atom to which they are attached, and the —CH 2 — contained in the ring is replaced by —O—, —S— or —CO— It is also good.
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.
A1 ^- represents an organic anion. ]

Examples of the divalent linking group represented by A ^II1 include a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group is It may be replaced by -O-, -S- or -CO-. Specifically, the same thing as the C1-C18 bivalent saturated hydrocarbon group represented by X ^III3 is mentioned.
A phenylene group, a naphthylene group, etc. are mentioned as a C6-C18 bivalent aromatic hydrocarbon group represented by R ^II1 .
A chain hydrocarbon group represented by R ^II2 and R ^II3 , an alicyclic hydrocarbon group, an aromatic hydrocarbon group, an alkoxy group which is a substituent of the chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic group A hydrocarbon group, a halogen atom which is a substituent of an alicyclic hydrocarbon group, an aliphatic hydrocarbon group, an alkyl carbonyl group, a halogen atom which is a substituent of an aromatic hydrocarbon group, and an alkoxy group have the above-mentioned formula (b2) The same as R ^{b4 to} R ^{b6 of} -1) can be mentioned.
Examples of the halogen atom represented by R ^II4 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
As the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^II4 is an alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^a8 The same thing is mentioned.

As a structural unit containing the cation in Formula (II-1-1), the structural unit etc. which are represented below are mentioned.

A ^- The organic anion represented by a sulfonic acid anion, sulfonyl imide anion, methide anion and a carboxylate anion, and the like. A ^- organic anion represented by the sulfonate anion are preferable, and as a sulfonate anion, more preferably an anion contained in the salt represented by the formula (I) above.

As a sulfonyl imide anion represented by A < ^- >, the following are mentioned.

The following are mentioned as a sulfonyl methide anion.

Examples of the carboxylate anion include the following.

As a structural unit represented by Formula (II-1-1), the structural unit etc. which are represented below are mentioned.

The content of the structural unit (II) in the case of containing the structural unit (II) in the resin (A) is preferably 1 to 20 mol% with respect to the total structural units of the resin (A). Preferably it is 2-15 mol%, More preferably, it is 3-10 mol%.

The resin (A) may have a structural unit other than the structural units described above, and such structural units include structural units known in the art.
The resin (A) is preferably a resin comprising a structural unit (a1) and a structural unit (s), that is, a copolymer of a monomer (a1) and a monomer (s).
The structural unit (a1) is preferably a group consisting of the structural unit (a1-0), the structural unit (a1-1) and the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group and a cyclopentyl group) It is at least one selected from, more preferably at least two.
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 Formula (a2-A). The structural unit (a3) is preferably a structural unit represented by formula (a3-1), a structural unit represented by formula (a3-2) and a group consisting of structural units represented by formula (a3-4) Or at least one selected from
Each structural unit constituting the resin (A) may be used alone or in combination of two or more, and is produced by a known polymerization method (for example, radical polymerization method) using a monomer leading to these structural units. be able to. The content rate of each structural unit which resin (A) has can be adjusted with the usage-amount of the monomer used for superposition | polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, still more preferably 3,000 or more), 50,000 or less (more preferably 30,000 or less, more preferably) Is less than 15,000). In the present specification, the weight average molecular weight is a value determined by gel permeation chromatography under the conditions described in the examples.

<Resins other than Resin (A)>
As resin other than resin (A), resin (Hereinafter, it may be mentioned resin (X), etc.) containing structural unit (a4) or structural unit (a5), etc. are mentioned.
Among them, as the resin (X), a resin containing a structural unit (a4) is preferable.
In the resin (X), the content of the structural unit (a4) is preferably 30 mol% or more, more preferably 40 mol% or more based on the total of all structural units of the resin (X). And 45 mol% or more.
As a structural unit which resin (X) may further have, a structural unit (a1), a structural unit (a2), a structural unit (a3), and a structural unit derived from other publicly known monomers are mentioned. Among them, the resin (X) is preferably a resin comprising only the structural unit (a4) and / or the structural unit (a5), and more preferably a resin comprising only the structural unit (a4).
Each structural unit constituting the resin (X) may be used alone or in combination of two or more, and it is produced by a known polymerization method (for example, radical polymerization method) using a monomer which derives these structural units. can do. The content rate of each structural unit which resin (X) has can be adjusted with the usage-amount of the monomer used for superposition | polymerization.
The weight average molecular weight of the resin (X) is preferably independently 6,000 or more (more preferably 7,000 or more) and 80,000 or less (more preferably 60,000 or less). The measuring means of the weight average molecular weight of resin (X) is the same as that of the case of resin (A).
When the resist composition of the present invention contains the resin (A2), the content thereof is usually 1 to 2500 parts by mass (more preferably 10 to 1000 parts by mass) with respect to 100 parts by mass of the resin (A). is there.
When the resist composition contains a resin (X), the content is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass with respect to 100 parts by mass of the resin (A). The amount is more preferably 1 to 40 parts by mass, particularly preferably 1 to 30 parts by mass, and particularly preferably 1 to 8 parts by mass.

  The content of the resin (A) in the resist composition is preferably 80% by mass to 99% by mass, and more preferably 90% by mass to 99% by mass, with respect to the solid content of the resist composition. Moreover, when resin other than resin (A) is included, the total content rate of resin (A) and resin other than resin (A) is 80 mass% or more and 99 mass% with respect to solid content of a resist composition. It is preferable that it is the following, and 90 to 99 mass% is more preferable. In the present specification, “solid content of resist composition” means the total of components excluding the solvent (E) described later from the total amount of the resist composition. The solid content of the resist composition and the resin content relative thereto can be measured by a known analytical means such as liquid chromatography or gas chromatography.

<Solvent (E)>
The content of the solvent (E) in the resist composition is usually 90% by mass to 99.9% by mass, preferably 92% by mass to 99% by mass, and more preferably 94% by mass to 99% by mass. % Or less. The content of the solvent (E) can be measured, for example, by a known analytical means such as liquid chromatography or gas chromatography.
As the solvent (E), 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; ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate Esters such as acetone, methyl isobutyl ketone, ketones such as 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; and the like. One of the solvents (E) may be used alone, or two or more thereof may be used.

<Quencher (C)>
Examples of the quencher (C) include basic nitrogen-containing organic compounds and salts which generate an acid having a weaker acidity than the acid generated from the acid generator (B). The content of the quencher (C) is preferably about 0.01 to 5% by mass based on the solid content of the resist composition.
Basic nitrogen-containing organic compounds include amines and ammonium salts. The amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines.
As the amine, 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline, diphenylamine, hexylamine, Heptylamine, Octylamine, Nonylamine, Decylamine, Dipentylamine, Dihexylamine, Diheptylamine, Dioctylamine, Dioctylamine, Didecylamine, Triethylamine, Trimethylamine, Tripropylamine, Tributylamine, Tripentylamine, Trihexylamine, Trihexylamine Heptylamine, trioctylamine, torinylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, Ludicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldionylamine, methyldidecylamine, ethyl dibutylamine, ethyl dipentylamine, ethyl dihexylamine, ethyl diheptylamine, ethyl dioctylamine, ethyl dinonylamine, ethyl Didecylamine, 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-methyl ester Dazole, pyridine, 4-methylpyridine, 1,2-di (2-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. are mentioned, Preferably aromatic amines, such as a diisopropyl aniline, are mentioned, More preferably, 2, 6- diisopropyl Aniline is mentioned.
As an ammonium salt, tetramethyl ammonium hydroxide, tetraisopropyl ammonium hydroxide, tetrabutyl ammonium hydroxide, tetrahexyl ammonium hydroxide, tetraoctyl ammonium hydroxide, phenyltrimethyl ammonium hydroxide, 3- (trifluoromethyl) phenyltrimethyl Ammonium hydroxide, tetra-n-butylammonium salicylate, choline and the like can be mentioned.

The acidity of a salt that generates an acid having a weaker acidity than the acid generated from the acid generator (B) is represented by the acid dissociation constant (pKa). The salt which generates an acid weaker in acidity than the acid generated from the acid generator (B) is a salt having an acid dissociation constant of -3 <pKa, preferably -1 <pKa. It is a salt of pKa <7, more preferably a salt of 0 <pKa <5.
As a salt that generates an acid having a weaker acidity than the acid generated from the acid generator (B), a salt represented by the following formula, a salt represented by the formula (D) described in JP-A-2015-147926 (Hereafter, it may be referred to as "weak acid inner salt (D)"), and JP-A-2012-229206, JP-A-2012-6908, JP-A-2012-72109, JP-A-2011-39502. The salt of Unexamined-Japanese-Patent No. and Unexamined-Japanese-Patent No. 2011-191745 is mentioned. A salt which generates an acid having a weaker acidity than the acid generated from the acid generator (B) is preferably a weak acid inner salt (D).

As the weak acid internal salt (D), the following salts may be mentioned.
When the resist composition contains a quencher (C), the content of the quencher (C) is usually 0.01 to 5% by mass, preferably 0.01 to 5% by mass in the solid content of the resist composition. It is 3% by mass.

<Other ingredients>
The resist composition of the present invention may optionally contain components other than the components described above (hereinafter sometimes referred to as "other components (F)"). There is no particular limitation on the other component (F), and additives known in the field of resist, for example, sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes and the like can be used.

Preparation of Resist Composition
The resist composition of the present invention comprises a salt (I) and a resin (A), and, if necessary, an acid generator (B), a resin other than the resin (A), a solvent (E) and a quencher (C) And other components (F) can be prepared by mixing. The order of mixing is arbitrary and is not particularly limited. The temperature for mixing can be selected from 10 to 40 ° C. according to the type of resin or the like, the solubility of the resin or the like in the solvent (E), and the like. The mixing time can be appropriately selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is also not particularly limited, and stirring and mixing can be used.
After mixing each component, it is preferable to filter using a filter with a pore size of about 0.003 to 0.2 μm.

<Method of manufacturing resist pattern>
The method for producing a resist pattern of the present invention is
(1) applying the resist composition of the present invention on a substrate,
(2) drying the composition after application to form a composition layer;
(3) exposing the composition layer,
(4) heating the composition layer after exposure; and (5) developing the composition layer after heating.

The resist composition can be applied onto a substrate by means of a commonly used apparatus such as a spin coater. Examples of the substrate include inorganic substrates such as silicon wafers. Before applying the resist composition, the substrate may be washed, or an antireflective film or the like may be formed on the substrate.
The solvent is removed by drying the composition after application to 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 using a pressure reducing device. The heating temperature is preferably 50 to 200 ° C., and the heating time is preferably 10 to 180 seconds. Moreover, it is preferable that the pressure at the time of vacuum-drying is about 1-1.0 * 10 < ⁵ > Pa.
The resulting composition layer is usually exposed using an exposure machine. The exposure device may be an immersion exposure device. The exposure light source, which emits laser light in a UV-region such as a KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), solid-state laser source (YAG or semiconductor laser Use various materials such as those emitting high-frequency laser light in far ultraviolet region or vacuum ultraviolet region by converting the wavelength of laser light from etc.), electron beam, irradiation with ultra-ultraviolet light (EUV), etc. Can. In the present specification, irradiation of these radiations may be collectively referred to as "exposure". At the time of exposure, the exposure is usually performed through a mask corresponding to the required pattern. When the exposure light source is an electron beam, direct exposure may be performed without using a mask.
The composition layer after exposure is subjected to heat treatment (so-called post-exposure baking) in order to accelerate the deprotection reaction of the acid labile group. The heating temperature is usually about 50 to 200 ° C, preferably about 70 to 150 ° C.
The composition layer after heating is usually developed using a developing solution using a developing device. As a developing method, a dip method, a paddle method, a spray method, a dynamic dispensing method and the like can be mentioned. The development temperature is preferably 5 to 60 ° C., for example, and the development time is preferably 5 to 300 seconds, for example. A positive resist pattern or a negative resist pattern can be produced by selecting the type of developer as follows.
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. For example, an aqueous solution of tetramethyl ammonium hydroxide or (2-hydroxyethyl) trimethyl ammonium hydroxide (commonly called choline) and the like can be mentioned. The alkaline developer may contain a surfactant.
After development, the resist pattern is preferably washed with ultrapure water, and then the substrate and water remaining on the pattern are removed.
When a negative resist pattern is produced from the resist composition of the present invention, a developer containing an organic solvent (hereinafter sometimes referred to as "organic developer") is used as a developer.
Examples of organic solvents contained in the organic developer 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; glycols such as propylene glycol monomethyl ether Ether solvents; Amide solvents such as N, N-dimethylacetamide; and Aromatic hydrocarbon solvents such as anisole.
The content of the organic solvent in the organic developer is preferably 90% by mass to 100% by mass, more preferably 95% by mass to 100% by mass, and still more preferably substantially only the organic solvent.
Among them, as the organic developer, a developer containing butyl acetate and / or 2-heptanone is preferable. The total content of butyl acetate and 2-heptanone in the organic developer is preferably 50% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, and substantially butyl acetate and / or 2 It is further preferred that only heptanone.
The organic developer may contain a surfactant. The organic developer may contain a slight amount of water.
At the time of development, development may be stopped by replacing with a solvent of a type different from that of the organic developer.
It is preferable to wash the developed resist pattern with a rinse solution. The rinse solution is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a common organic solvent can be used, and is preferably an alcohol solvent or an ester solvent.
After cleaning, it is preferable to remove the rinse solution remaining on the substrate and the pattern.

<Use>
The resist composition of the present invention is 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, particularly ArF It is suitable as a resist composition for excimer laser exposure, and is useful for fine processing of a semiconductor.

The present invention will be more specifically described by way of examples. In the examples, "%" and "part" representing the content or the amount used are on a mass basis unless otherwise stated.
The weight average molecular weight is a value determined by gel permeation chromatography. The analysis conditions for gel permeation chromatography are as follows.
Column: TSKgel Multipore HXL-M x 3 + guardcolumn (made by Tosoh Corporation)
Eluent: tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (made by Tosoh Corporation)
The structure of the compound was confirmed by measuring molecular ion peaks using mass spectrometry (LC: Agilent 1100 type, MASS: Agilent LC / MSD type). In the following examples, this molecular ion peak value is indicated by "MASS".

Example 1: Synthesis of a salt represented by formula (I-1)
Ten parts of the salt represented by the formula (I-1-a), 2.79 parts of the compound represented by the formula (I-1-b), and 40 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. After 2.49 parts of trifluoromethanesulfonic acid was added to the obtained mixed solution, the mixture was stirred under reflux for 12 hours at 60 ° C. in the presence of molecular sieve (MS (3A)). To the obtained reaction mixture, 40 parts of ion exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes, and then separated to extract an organic layer. This water washing operation was repeated 15 times. The obtained organic layer is concentrated, 50 parts of tert-butyl methyl ether is added to the concentrated mixture, and after stirring for 30 minutes at 23 ° C., the salt represented by the formula (I-1) is filtered. I got 5.89 copies.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 433.1

Example 2: Synthesis of a salt represented by formula (I-2)
Ten parts of the salt represented by the formula (I-1-a), 3.24 parts of the compound represented by the formula (I-2-b), and 40 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. After 2.49 parts of trifluoromethanesulfonic acid was added to the obtained mixed solution, the mixture was stirred under reflux for 12 hours at 60 ° C. in the presence of molecular sieve (MS (3A)). To the obtained reaction mixture, 40 parts of ion exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes, and then separated to extract an organic layer. This water washing operation was repeated 15 times. The obtained organic layer is concentrated, 50 parts of tert-butyl methyl ether is added to the concentrated mixture, and after stirring for 30 minutes at 23 ° C., the salt represented by the formula (I-2) is filtered. I got 7.24 copies.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 451.1

Example 3: Synthesis of a salt represented by formula (I-10)
Ten parts of the salt represented by the formula (I-10-a), 2.07 parts of the compound represented by the formula (I-2-b), and 40 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. After 1.85 parts of trifluoromethanesulfonic acid was added to the obtained mixed solution, the mixture was stirred under reflux for 12 hours at 60 ° C. in the presence of molecular sieve (MS (3A)). To the obtained reaction mixture, 40 parts of ion exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes, and then separated to extract an organic layer. This water washing operation was repeated 15 times. After filtering the obtained organic layer, the filtrate is concentrated, 30 parts of tert-butyl methyl ether is added to the concentration residue, and after stirring for 30 minutes at 23 ° C., the supernatant is removed, Concentration gave 3.89 parts of a salt represented by formula (I-10).
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 659.2

Example 4: Synthesis of a salt represented by formula (I-4)
Ten parts of the salt represented by the formula (I-4-a), 3.24 parts of the compound represented by the formula (I-2-b), and 40 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. After 2.49 parts of trifluoromethanesulfonic acid was added to the obtained mixed solution, the mixture was stirred under reflux for 12 hours at 60 ° C. in the presence of molecular sieve (MS (3A)). To the obtained reaction mixture, 40 parts of ion exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes, and then separated to extract an organic layer. This water washing operation was repeated 15 times. The resulting organic layer is concentrated, 50 parts of tert-butyl methyl ether is added to the concentrated mixture, and after stirring for 30 minutes at 23 ° C., the salt represented by the formula (I-4) is filtered. Obtained 8.21 copies.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 451.1

Example 5: Synthesis of salt represented by formula (I-136)
Ten parts of the salt represented by the formula (I-136-a), 2.03 parts of the compound represented by the formula (I-2-b), and 40 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. After 1.85 parts of trifluoromethanesulfonic acid was added to the obtained mixed solution, the mixture was stirred under reflux for 12 hours at 60 ° C. in the presence of molecular sieve (MS (3A)). To the obtained reaction mixture, 40 parts of ion exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes, and then separated to extract an organic layer. This water washing operation was repeated 15 times. After filtering the obtained organic layer, the filtrate is concentrated, 30 parts of tert-butyl methyl ether is added to the concentration residue, and after stirring for 30 minutes at 23 ° C., the supernatant is removed, Concentration gave 3.44 parts of a salt represented by formula (I-136).
MASS (ESI (+) Spectrum): M ⁺ 281.1
MASS (ESI (-) Spectrum): M ^- 659.2

Example 6: Synthesis of salt represented by formula (I-154)
Ten parts of the salt represented by the formula (I-154-a), 1.94 parts of the compound represented by the formula (I-2-b), and 40 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. After 1.85 parts of trifluoromethanesulfonic acid was added to the obtained mixed solution, the mixture was stirred under reflux for 12 hours at 60 ° C. in the presence of molecular sieve (MS (3A)). To the obtained reaction mixture, 40 parts of ion exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes, and then separated to extract an organic layer. This water washing operation was repeated 15 times. After filtering the obtained organic layer, the filtrate is concentrated, 30 parts of tert-butyl methyl ether is added to the concentration residue, and after stirring for 30 minutes at 23 ° C., the supernatant is removed, Concentration gave 3.22 parts of a salt represented by formula (I-154).
MASS (ESI (+) Spectrum): M ⁺ 317.1
MASS (ESI (-) Spectrum): M ^- 659.2

Synthesis of Resin The compounds (monomers) used in the synthesis of the resin are shown below. Hereinafter, these monomers are called "monomer (a1-1-3)" etc. according to a formula number.

Synthesis Example 1 [Synthesis of Resin A1]
As a monomer, a monomer (a1-4-2), a monomer (a1-1-3), a monomer (a1-2-6) and a monomer (II-2-A-1-1) are used, and their molar ratio [monomer (A1-4-2): Monomer (a1-1-3): Monomer (a1-2-6): Monomer (II-2-A-1-1)] in a ratio of 35: 24: 38: 3 It mixed so that it became, Furthermore, 1.5 mass times methyl isobutyl ketone was mixed with this monomer mixture with respect to the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile as an initiator is added so as to be 7 mol% relative to the total number of moles of all monomers, and polymerization is carried out by heating this at 83 ° C. for about 5 hours The Then, p-toluenesulfonic acid aqueous solution was added to the polymerization reaction liquid, and after stirring for 6 hours, liquid separation was carried out. The obtained organic layer is poured into a large amount of n-heptane to precipitate a resin, followed by filtration and recovery to obtain a resin A1 (copolymer) having a weight average molecular weight of about 4.8 × 10 ³ in a yield of 78 Obtained in%. This resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin A2]
As a monomer, a monomer (a1-4-2), a monomer (a1-1-3) and a monomer (a1-2-6) are used, and their molar ratio [monomer (a1-4-2): monomer (a1-1) -3): Monomer (a1-2-6)] is mixed in a ratio of 38:24:38, and further 1.5 mass times the total mass of all monomers in this monomer mixture. Of methyl isobutyl ketone were mixed. To the obtained mixture, azobisisobutyronitrile as an initiator is added so as to be 7 mol% relative to the total number of moles of all monomers, and polymerization is carried out by heating this at 85 ° C. for about 5 hours The Then, p-toluenesulfonic acid aqueous solution was added to the polymerization reaction liquid, and after stirring for 6 hours, liquid separation was carried out. The obtained organic layer is poured into a large amount of n-heptane to precipitate a resin, followed by filtration and recovery to obtain a resin A2 (copolymer) having a weight average molecular weight of about 4.6 × 10 ^3. Obtained in%. This resin A2 has the following structural units.

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

<Resin (A)>
A1, A2: Resin A1, Resin A2
<Salt (I)>
I-1: Salt represented by Formula (I-1) I-2: Salt represented by Formula (I-2) I-4: Salt represented by Formula (I-4) I-10: Formula The salt represented by (I-10) I-136: The salt represented by the formula (I-136) I-154: The salt represented by the formula (I-154) <Acid generator (B)>
IX-1: a salt represented by formula (IX-1); synthesized by the method described in JP-A-2012-144516
IX-2: a salt represented by the formula (IX-2); synthesized by the method described in JP-A-2009-137873
IX-3: a salt represented by the formula (IX-3); synthesized by the method described in JP-A 2013-053137
<Quencher (C)>
C1-1: synthesized by the method described in JP-A-2011-39502
<Solvent (E)>
Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 100 parts γ-butyrolactone 5 parts

(Evaluation of electron beam exposure of resist composition)
A six inch silicon wafer was treated at 90 ° C. for 60 seconds with hexamethyldisilazane on a direct hot plate. The resist composition was spin-coated on the silicon wafer such that the thickness of the composition layer was 0.04 μm. Thereafter, on the direct hot plate, the composition layer was formed by prebaking at a temperature shown in the “PB” column of Table 2 for 60 seconds. A line and space pattern was directly drawn on the composition layer formed on the wafer using an electron beam drawing machine ("HL-800D 50 keV" manufactured by Hitachi, Ltd.) and changing the exposure amount stepwise. .
After exposure, post exposure baking is performed for 60 seconds at the temperature shown in the “PEB” column of Table 2 on a hot plate, and paddle development is further performed for 60 seconds with a 2.38 mass% tetramethylammonium hydroxide aqueous solution. The resist pattern was obtained.
The obtained resist pattern (line and space pattern) was observed with a scanning electron microscope, and the exposure amount at which the line width and space width of the 60 nm line and space pattern become 1: 1 was taken as the effective sensitivity.

Line edge roughness evaluation (LER): The fluctuation width of the unevenness of the side wall surface of the resist pattern manufactured with the effective sensitivity was measured with a scanning electron microscope to obtain the line edge roughness. The results are shown in Table 3.

From the above results, it can be seen that the line edge roughness (LER) is good according to the salt of the present invention and the resist composition containing the salt.

  The salt of the present invention and a resist composition containing the salt have good line edge roughness and are useful for semiconductor microfabrication.

Claims (9)

A salt represented by formula (I).
[In the formula (I),
Each of Q ¹ and Q ² independently represents a fluorine atom or a C 1 to C 6 perfluoroalkyl group.
R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or a C ^{1 to} C 6 perfluoroalkyl group.
z represents any integer of 0 to 6, and when z is 2 or more, plural R ^{1 s} and R ^{2 s} may be the same as or different from each other.
L ¹ represents a divalent hydrocarbon group having 1 to 36 carbon atoms which may have a substituent, and -CH _2- contained in the hydrocarbon group is -O-, -S-,- It may be replaced by CO- or -SO _2- .
W ¹ represents a hydrocarbon ring of 3 to 18 carbon atoms which may have a substituent, and -CH _2- contained in the hydrocarbon ring is -O-, -S-, -CO- or It may be replaced by -SO _2- .
R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom, a fluorine atom or a hydrocarbon group having 1 to 12 carbon atoms, and -CH _2- contained in the hydrocarbon group is -O- or- It may be replaced by CO-.
Z ⁺ represents an organic cation. ] L ¹ is * -CO-O-L ² -or * -O-CO-L ^2- (L ² is a single bond, C 1 -C 6 alkanediyl group, C 1 -C 6 alkanediyl group And -C 2 -C 18 alicyclic hydrocarbon group are combined, and -CH _2- contained in L ¹ is substituted by -O-, -S-, -CO- or -SO _2- The salt according to claim 1, wherein * represents a bonding position with C (R ¹ ) (R ² ) or C (Q ¹ ) (Q ² ). The salt according to claim 1 or 2, wherein W ¹ is an adamantane ring. The salt according to any one of claims 1 to 3, wherein R ⁴ is a hydrogen atom or a fluorine atom. The salt according to any one of claims 1 to 4, wherein R ³ and R ⁵ are a hydrogen atom.   The acid generator containing the salt in any one of Claims 1-5.   A resist composition comprising the acid generator according to claim 6 and a resin having an acid labile group.   8. The resist composition according to claim 7, containing a salt that generates an acid having a weaker acidity than an acid generated from an acid generator. (1) applying the resist composition according to claim 7 or 8 onto a substrate;
(2) drying the composition after application to form a composition layer;
(3) exposing the composition layer,
(4) A method of producing a resist pattern, comprising the steps of: heating the composition layer after exposure; and (5) developing the composition layer after heating.