JP2020105165A - 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 a good mask error factor (MEF), and a resist composition containing the salt.SOLUTION: The salt represented by formula (I), an acid generator, and the resist composition containing the same are provided. [In the formula, Q1 and Q2 each represent a fluorine atom, a perfluoroalkyl group or the like; R1 and R2 each represent a hydrogen atom, a fluorine atom, a perfluoroalkyl group or the like; z represents an integer of 0-6; X1 represents *-CO-O-, *-O-CO-, *-O-CO-O- or *-O-; L1 represents a single bond or a saturated hydrocarbon group; A1 represents an optionally substituted divalent alicyclic hydrocarbon group; Ra represents an optionally substituted alicyclic hydrocarbon group, and -CH2- contained in the group may be substituted with -O-, -S-, -SO2- or -CO-, provided that at least one -CH2- contained in the alicyclic hydrocarbon group is substituted with -O- or -CO-; and Z+ represents an organic cation.]SELECTED DRAWING: None

Description

The present invention relates to a salt for an acid generator used for fine processing of semiconductors, an acid generator containing the salt, a resist composition and a method for producing a resist pattern.

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

JP, 2007-161707, A JP, 2007-145824, A JP, 2008-048106, A

An object of the present invention is to provide a salt that forms a resist pattern having a better mask error factor (MEF) than a resist pattern formed from a resist composition containing the above salt.

The present invention includes the following inventions.
[1] A salt represented by the formula (I).
[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
z represents an integer of 0 to 6, and when z is 2 or more, a plurality of R ¹ and R ² may be the same or different.
X ¹ is, * - CO-O -, * - O-CO -, * - O-CO-O- or * -O- (where * ^{is, C (R 1) (R} 2) or C (Q ¹ ) represents a bonding position with (Q ² ).
L ¹ represents a single bond or a saturated hydrocarbon group having 1 to 28 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group is —O—, —S—, —SO ₂ — or —CO—. May be replaced with.
A ¹ represents a divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and —CH ₂ — contained in the alicyclic hydrocarbon group is —O—, -S -, - SO ₂ - or -CO- may be replaced with.
R ^a represents an alicyclic hydrocarbon group which may having from 3 to 18 carbon atoms which may have a substituent, -CH ₂ contained in the alicyclic hydrocarbon group - is -O -, - S- , -SO ₂ - may be replaced or -CO-. However, at least one of —CH ₂ — contained in the alicyclic hydrocarbon group is replaced with —O— or —CO—.
Z ⁺ represents an organic cation. ]
[2] X ¹ is a bond with *-CO-O- or *-O-CO-O- (where * represents C(R ¹ )(R ² ) or C(Q ¹ )(Q ² ). The salt according to [1].
[3] L ¹ is a single bond, an alkanediyl group (however, —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—), or an alkanediyl group and a fat. A group formed by combining with a cyclic saturated hydrocarbon group (however, —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—, and the alicyclic saturated hydrocarbon group is, -O - - -CH _{2 contained, - S -, - SO 2} -. of or -CO- may be substituted with) a [1] or [2] salt according.
[4] R ^a is a hydroxy group or ^a C 3-18 alicyclic hydrocarbon group which may have a fluorine atom (-CH _2- contained in the alicyclic hydrocarbon group is -O-. , -S -, - SO ₂ - or may be replaced by -CO-, however, -CH ₂ contained in the alicyclic hydrocarbon group -. At least one of, -O- or -CO- in The salt according to any one of [1] to [3].
[5] An acid generator containing the salt according to any one of [1] to [4].
[6] A resist composition containing the acid generator according to [5] and a resin containing a structural unit having an acid labile group.
[7] The structural unit having an acid labile group includes at least one selected from the group consisting of a structural unit represented by the formula (a1-1) and a structural unit represented by the formula (a1-2) [ 6] The resist composition as described above.
[In Formula (a1-1) and Formula (a1-2),
L ^a1 and L ^a2 each independently represent -O- or *-O-(CH ₂ ) _k1- CO-O-, k1 represents an integer of 1 to 7, and * represents -CO-. Represents a bond with.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these.
m1 represents any integer of 0-14.
n1 represents any integer of 0-10.
n1′ represents an integer of 0 to 3. ]
[8] The resist composition according to [6] or [7], further containing a salt that generates an acid having a weaker acidity than the acid generated from the acid generator.
[9] The resist composition according to any one of [6] to [8], which further contains a resin containing a structural unit having a fluorine atom.
[10] (1) A step of applying the resist composition according to any one of [6] to [9] onto a substrate,
(2) a step of drying the composition after coating to form a composition layer,
(3) exposing the composition layer
A method for producing a resist pattern, comprising the step of (4) heating the composition layer after exposure, and (5) developing the composition layer after heating.

By using the resist composition using the salt of the present invention, a resist pattern can be produced with a good mask error factor (MEF).

In the present specification, the “(meth)acrylic monomer” includes a monomer having a structure of “CH ₂ ═CH—CO—” and a monomer having a structure of “CH ₂ ═C(CH ₃ )—CO—”. It means at least one selected from the group consisting of Similarly, "(meth)acrylate" and "(meth)acrylic acid" mean "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. If _{"CH 2 = C (CH 3)} -CO- " or "CH ₂ = CH-CO-" structural unit having a are illustrated, structural units having both groups are exemplified similarly I shall. In addition, any of the groups described in the present specification that can have both a linear structure and a branched structure may be used. The “combined group” means a group in which two or more kinds of the exemplified groups are bonded, and the valence of these groups may be appropriately changed depending on the bonding form. When stereoisomers are present, all stereoisomers are included.
In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (E) described below from the total amount of the resist composition.

<Salt represented by formula (I)>
The present invention relates to a salt represented by the formula (I) (hereinafter sometimes referred to as “salt (I)”).
In salt (I), the side having a negative charge may be referred to as “anion (I)”, and the side having a positive charge may be referred to as “cation (I)”.

In formula (I), the perfluoroalkyl group of Q ¹ , Q ² , R ¹ and R ² is a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group. , Perfluoro tert-butyl group, perfluoro pentyl group, perfluoro hexyl group and the like.
Q ¹ and Q ² are each independently preferably a trifluoromethyl group or a fluorine atom, and more preferably a fluorine atom.
R ¹ and R ² are each independently preferably a hydrogen atom or a fluorine atom.
It is preferable that z is 0 or 1.
X ¹ is *-CO-O-, *-O-CO- or *-O-CO-O-(* is C(R ¹ )(R ² ), or C(Q ¹ )(Q ² ). It is preferably a bond, and *-CO-O- or *-O-CO-O-(* represents C(R ¹ )(R ² )or C(Q ¹ )(Q ² ). Is more preferable).

Examples of the divalent saturated hydrocarbon group represented by L ¹ include an alkanediyl group and a monocyclic or polycyclic (including a spiro ring) divalent alicyclic saturated hydrocarbon group. A group obtained by combining two or more types of groups (for example, a divalent hydrocarbon group formed from an alicyclic saturated hydrocarbon group and an alkanediyl group) may be used.
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 , Straight chain 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;
Ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- A branched alkanediyl group such as a 1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, a 2-methylbutane-1,4-diyl group;
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 and the like. Valent alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbon such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group and adamantane-2,6-diyl group Groups and the like.
—CH ₂ — contained in the divalent saturated hydrocarbon group having ¹ to 28 carbon atoms of L ¹ may be replaced with —O—, —S—, —SO ₂ — or —CO—.
Is -O - - -CH ₂ contained in the divalent saturated hydrocarbon group having a carbon number of 1 to 28, represented by ^{L 1, - S -, -} SO 2 - or if the are replaced with -CO-, replace Let the previous carbon number be the carbon number of the saturated hydrocarbon group.
L ¹ is a single bond, an alkanediyl group having 1 to 4 carbon atoms (provided that —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—) or the number of carbon atoms. A group formed by combining an alkanediyl group having 1 to 4 and an alicyclic saturated hydrocarbon group having 3 to 18 carbon atoms (however, —CH ₂ — contained in the alkanediyl group is —O— or —CO—. May be replaced with, and —CH ₂ — contained in the alicyclic saturated hydrocarbon group may be replaced with —O—, —S—, —SO ₂ — or —CO—). Preferably, a single bond, an alkanediyl group having 1 to 4 carbon atoms or a combination of an alkanediyl group having 1 to 4 carbon atoms and an alicyclic saturated hydrocarbon group having 3 to 18 carbon atoms (however, —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—), more preferably a single bond, an alkanediyl group having 1 to 4 carbon atoms or 1 carbon atom. A group formed by combining an alkanediyl group of 4 to an adamantanediyl group (however, —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—). Is more preferable.
Examples of the group formed by combining the alkanediyl group and the alicyclic saturated hydrocarbon group include *-alicyclic saturated hydrocarbon group-alkanediyl group, *-alkanediyl group-alicyclic saturated hydrocarbon group, and * - alkanediyl group - alicyclic saturated hydrocarbon group - alkanediyl group (. * is representative of a bond between X ¹⁾ can be mentioned.

Examples of the divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms of A ¹ include monocyclic or polycyclic (including spiro ring) divalent alicyclic hydrocarbon groups.
Examples of the monocyclic divalent alicyclic hydrocarbon group include cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group and cyclooctane-1,5. A cycloalkanediyl group such as a -diyl group.
Examples of the polycyclic divalent alicyclic hydrocarbon group include norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-2,2-diyl group, adamantane-1,5-diyl group. Group, an adamantane-2,6-diyl group and the like.
The substituent that the alicyclic hydrocarbon group of A ¹ may have includes a halogen atom, a hydroxy group, a cyano group, a carboxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and The group which combined 2 or more types among these groups is mentioned.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, octyl group and nonyl group.
Examples of the alkoxy group having 1 to 12 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group. Group, dodecyloxy group and the like.
Examples of the group in which two or more kinds are combined include 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.
The alkoxycarbonyl group having 2 to 13 carbon atoms, the alkylcarbonyl group having 2 to 13 carbon atoms, the alkylcarbonyloxy group having 2 to 13 carbon atoms and the like have a carbonyl group or a carbonyloxy group bonded to the above alkyl group or alkoxy group. Represents a group.
Examples of the alkoxycarbonyl group having 2 to 13 carbon atoms include methoxycarbonyl group, ethoxycarbonyl group and butoxycarbonyl group, and examples of the alkylcarbonyl group having 2 to 13 carbon atoms include acetyl group, propionyl group and butyryl group. Examples of the alkylcarbonyloxy group having 2 to 13 carbon atoms include an acetyloxy group, a propionyloxy group and a butyryloxy group.
The divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms represented by A ¹ may have one substituent or a plurality of the same or different substituents.
-CH ₂ contained in the divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms of A ¹ - is, -O -, - S -, - CO- or -SO ₂ - may be replaced with.
When the divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms represented by A ¹ has a substituent, or —CH ₂ — contained in the alicyclic hydrocarbon group is —O—, —S. -, - CO- or -SO 2 _- if the are replaced, the number of carbon atoms before the alicyclic hydrocarbon group of carbon number of a replacement.
As the substituent, a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms is preferable, and a fluorine atom or a hydroxy group is more preferable.

The divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms represented by A ¹ is a monocyclic divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms such as cyclopentanediyl group and cyclohexanediyl group. (- is, -O - -CH ₂ contained in the alicyclic hydrocarbon group, - S -, - CO- or -SO ₂ -. which may be replaced by a) hydrogen group is preferably, cyclopentane A diyl group or a cyclohexanediyl group is more preferable, and a cyclohexanediyl group is further preferable.

Examples of the alicyclic saturated hydrocarbon group having 3 to 18 carbon atoms represented by ^Ra include monocyclic or polycyclic (including spiro ring) alicyclic saturated hydrocarbon groups.
Examples of the monocyclic alicyclic saturated hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group.
Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include a norbornyl group and an adamantyl group.

Examples of the substituent that the alicyclic hydrocarbon group of ^Ra may have include a halogen atom, a hydroxy group, a cyano group, a carboxy group, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms. And groups in which two or more of these groups are combined.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, octyl group and nonyl group.
Examples of the alkoxy group having 1 to 12 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group. Group, dodecyloxy group and the like.
Examples of the group in which two or more kinds are combined include 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.
The alkoxycarbonyl group having 2 to 13 carbon atoms, the alkylcarbonyl group having 2 to 13 carbon atoms and the alkylcarbonyloxy group having 2 to 13 carbon atoms are groups in which a carbonyl group or a carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group. Represents.
Examples of the alkoxycarbonyl group having 2 to 13 carbon atoms include methoxycarbonyl group, ethoxycarbonyl group and butoxycarbonyl group, and examples of the alkylcarbonyl group having 2 to 13 carbon atoms include acetyl group, propionyl group and butyryl group. Examples of the alkylcarbonyloxy group having 2 to 13 carbon atoms include an acetyloxy group, a propionyloxy group and a butyryloxy group.
The alicyclic hydrocarbon group having 3 to 18 carbon atoms represented by ^Ra may have one substituent or a plurality of substituents.
As the substituent, a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms is preferable, and a fluorine atom or a hydroxy group is more preferable.

-CH ₂ - contained in the alicyclic hydrocarbon group having 3 to 18 carbon atoms represented by R ^a - is, -O -, - S -, - CO- or -SO ₂ - may be replaced with. However, at least one of —CH ₂ — contained in the alicyclic hydrocarbon group is replaced with —O— or —CO—.
Is -O - - -CH ₂ alicyclic hydrocarbon group having 3 to 18 carbon atoms represented by R ^a is contained in the case or alicyclic hydrocarbon group having a substituent, - S -, - CO - or -SO 2 _- if the are replaced, the number of carbon atoms before the alicyclic hydrocarbon group of carbon number of a replacement.

As R ^{a, a} group in which —CH ₂ — contained in the alicyclic hydrocarbon group having 3 to 18 carbon atoms is replaced with —CO—, or —CO— contained in the replaced group is a cyclic ketal (however, The hydrogen atom contained in the cyclic ketal structure may be substituted with a fluorine atom), and is preferably a monocyclic alicyclic hydrocarbon group having 3 to 12 carbon atoms such as cyclohexyl group. A group in which —CH ₂ — contained in is replaced by —CO— or —CO— contained in the replaced group is a cyclic ketal (however, a hydrogen atom contained in the cyclic ketal structure may be substituted with a fluorine atom). .) is more preferable, and a group represented by the following (* represents a bonding position with A ¹ ) is further preferable.

Examples of the anion (I) include the following anions. Among them, the anions represented by formula (Ia-1) to formula (Ia-3), formula (Ia-13) to formula (Ia-17), formula (Ia-19) and formula (Ia-20) are preferable.

Examples of the Z ⁺ organic cation include an organic onium cation, an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation, and an organic phosphonium cation. Among these, organic sulfonium cations and organic iodonium cations are preferable, and aryl sulfonium cations are more preferable. Specifically, a cation represented by any of the formulas (b2-1) to (b2-4) (hereinafter, may be referred to as “cation (b2-1)” depending on the formula number). Can be mentioned.
In formula (b2-1) to formula (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 which may be substituted and is contained in the alicyclic hydrocarbon group is a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms or a glycidyloxy group. It may be substituted, 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 ^b4 and R ^b5 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, and —CH ₂ — contained in the ring is —O—, —S— or It may be replaced with -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 0-5.
When m2 is 2 or more, a plurality of R ^b7 may be the same or different, and when n2 is 2 or more, a plurality of R ^b8 may be the same or different.
R ^b9 and R ^b10 each independently represent a chain hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms.
R ^b9 and R ^b10 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, and —CH ₂ — contained in the ring is —O—, —S— or It may be replaced with -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 included in the chain hydrocarbon group. The hydrogen atom may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group may be an alkoxy group having 1 to 12 carbon atoms or 1 to 12 carbon atoms. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may be bonded to 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.
R ^{b13 to} R ^b18 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.
L ^b31 represents a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represent an integer of 0 to 5.
q2 and r2 each independently represent an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, a plurality of R ^b13 are the same or different, when p2 is 2 or more, a plurality of R ^b14 are the same or different, and when q2 is 2 or more, a plurality of R ^b15 are the same or different. , 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 are the same or different, and when t2 is 2 or more, the plurality of R ^b18 are the same or different. different.

The aliphatic hydrocarbon group represents a chain hydrocarbon group and an alicyclic hydrocarbon group.
Examples of the chain hydrocarbon group include an alkyl group such as 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. Can be mentioned.
In particular, the chain hydrocarbon group represented by R ^{b9 to} R ^b12 preferably has 1 to 12 carbon atoms.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group may be a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group or a cyclohexyl group. Examples thereof include cycloalkyl groups such as a heptyl group, a cyclooctyl group, and a cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups.
In particular, the alicyclic hydrocarbon group represented by R ^{b9 to} R ^b12 preferably has 3 to 18 carbon atoms, and more preferably 4 to 12 carbon atoms.
Examples of the alicyclic hydrocarbon group having a hydrogen atom substituted with an aliphatic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-methyladamantan-2-yl group, and a 2-ethyladamantan-2-yl group. , 2-isopropyladamantan-2-yl group, methylnorbornyl group, isobornyl group and the like. In the alicyclic hydrocarbon group having a hydrogen atom 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, biphenyl group, naphthyl group and phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and an aromatic hydrocarbon group having a chain hydrocarbon group having 1 to 18 carbon atoms (tolyl group, xylyl group). Groups, cumenyl groups, mesityl groups, p-ethylphenyl groups, p-tert-butylphenyl groups, 2,6-diethylphenyl groups, 2-methyl-6-ethylphenyl groups, etc.), and C3-18 fats. Examples thereof include an aromatic hydrocarbon group having a cyclic hydrocarbon group (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.). When the aromatic hydrocarbon group has a chain hydrocarbon group or an alicyclic hydrocarbon group, a chain hydrocarbon group having 1 to 18 carbon atoms and an alicyclic hydrocarbon group having 3 to 18 carbon atoms Is preferred.
A p-methoxyphenyl group etc. are mentioned as an aromatic hydrocarbon group by which the hydrogen atom was substituted by the alkoxy group.
Examples of the chain hydrocarbon group having a hydrogen atom 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 a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, an isopropylcarbonyloxy group, a butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, a pentylcarbonyloxy group. , A hexylcarbonyloxy group, an octylcarbonyloxy group and a 2-ethylhexylcarbonyloxy group.

The ring formed by combining R ^b4 and R ^b5 with each other and the sulfur atom to which they are bonded is monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated. May be a ring. Examples of this ring include a ring having 3 to 18 carbon atoms, and preferably a ring having 4 to 18 carbon atoms. The ring containing a sulfur atom may be a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring, and examples thereof include the following rings. * Represents a binding site.
The ring formed by R ^b9 and R ^{b10 taken} together may be any of a monocyclic ring, a polycyclic ring, an aromatic ring, a non-aromatic ring, a saturated ring and an unsaturated ring. This ring includes a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring. Examples thereof include thiolane-1-ium ring (tetrahydrothiophenium ring), thian-1-ium ring, and 1,4-oxathian-4-ium ring.
The ring formed by R ^b11 and R ^{b12 taken} together may be any of a monocyclic ring, a polycyclic ring, an aromatic ring, a non-aromatic ring, a saturated ring and an unsaturated ring. This ring includes a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring. Examples thereof include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

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

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

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

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

Examples of the salt (I) include the salts shown in Table 1. For example, in Table 1, salt (I-1) is a salt composed of an anion represented by formula (Ia-1) and a cation represented by formula (b2-c-1). is there.

Among them, salt (I) includes salt (I-1) to salt (I-3), salt (I-13) to salt (I-17), salt (I-19) to salt (I-23). , Salt (I-33) to salt (I-37), salt (I-39) to salt (I-43), salt (I-53) to salt (I-57), salt (I-59) to Salt (I-63), salt (I-73) to salt (I-77), salt (I-79) to salt (I-83), salt (I-93) to salt (I-97), salt (I-99) to salt (I-103), salt (I-113) to salt (I-117), salt (I-119) to salt (I-123), salt (I-133) to salt ( I-137), salt (I-139) to salt (I-143), salt (I-153) to salt (I-157), salt (I-159) to salt (I-163), salt (I -173) to salt (I-177), salt (I-179) to salt (I-183), salt (I-193) to salt (I-197), salt (I-199), salt (I- 200) is preferred.

<Method for producing salt (I)>
In the salt (I), a salt in which X ¹ is *-CO—O— (a salt represented by the formula (I1)) is, for example, a salt represented by the formula (I1-a) and carbonyldiimidazole. Can be produced by reacting in a solvent and then further reacting with a compound represented by the formula (I1-b).
(In the formula, all symbols have the same meanings as described above.)
Examples of the solvent in this reaction include chloroform and acetonitrile.
The reaction temperature is generally 5°C to 80°C, and the reaction time is generally 0.5 hr to 24 hr.

Examples of the salt represented by the formula (I1-a) include salts represented by the following, and the salt can be produced by the method described in JP 2008-127367 A.
Examples of the compound represented by the formula (I1-b) include compounds represented by the following formula and the like, which can be easily obtained from the market and can be easily produced by a known production method. it can.

In the salt (I), a salt in which X ¹ is *—O—CO—O— (a salt represented by the formula (I2)) includes, for example, a salt represented by the formula (I2-a) and a carbonyldione. It can be produced by reacting with imidazole in a solvent and then further reacting with a compound represented by the formula (I1-b).
In addition, the salt represented by the formula (I2) is obtained by, for example, reacting the compound represented by the formula (I1-b) with carbonyldiimidazole in a solvent, and then further reacting with the formula (I2-a). It can also be produced by reacting with the salt shown.
(In the formula, all symbols have the same meanings as described above.)
Examples of the solvent in this reaction include chloroform and acetonitrile.
The reaction temperature is generally 5°C to 80°C, and the reaction time is generally 0.5 hr to 24 hr.
Examples of the salt represented by the formula (I2-a) include salts represented by the following, and the salt can be produced by the method described in JP 2012-193170 A.

In the salt (I), a salt in which X ¹ is *-O—CO— (a salt represented by the formula (I3)) is, for example, a compound represented by the formula (I3-b) in a solvent. , Carbonyldiimidazole, and then further reacted with a salt represented by the formula (I2-a).
(In the formula, all symbols have the same meanings as described above.)
Examples of the solvent in this reaction include chloroform and acetonitrile.
The reaction temperature is generally 5°C to 80°C, and the reaction time is generally 0.5 hr to 24 hr.
Examples of the compound represented by the formula (I3-b) include compounds represented by the following formula and the like, which can be easily obtained from the market.

In the salt (I), a salt in which X ¹ is —O— (a salt represented by the formula (I4)) includes a salt represented by the formula (I2-a) and a salt represented by the formula (I1-b). The compound can be obtained by reacting with a compound in a solvent in the presence of a base.
(In the formula, all symbols have the same meanings as described above.)
Examples of the base in this reaction include potassium hydroxide and the like.
Examples of the solvent in this reaction include acetonitrile and the like.
The reaction temperature is generally 5°C to 80°C, and the reaction time is generally 0.5 hr to 24 hr.

In the salt (I), L ¹ is *-L ^I4- Ad-L ^I5- O-CO-O-L ^I6 --(a salt represented by the formula (I5)) ( ^LI4 , ^LI5 and L ^I6 independently represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, and at least one of L ^I4 , L ^I5, and L ^I6 represents an alkanediyl group having 1 to 6 carbon atoms. Represents an adamantanediyl group, and * represents a bonding position with X ^1. ) represents, for example, a salt represented by the formula (I5-a) and a compound represented by the formula (I5-b), It can be produced by reacting in a solvent.
(In the formula, all symbols have the same meanings as described above.)
The reaction temperature is generally 5°C to 80°C, and the reaction time is generally 0.5 hr to 24 hr.
Examples of the solvent in this reaction include chloroform and acetonitrile.
Examples of the salt represented by the formula (I5-a) include salts represented by the following, and the salt can be produced by the method described in JP 2012-72109 A.
Examples of the compound represented by the formula (I5-b) include compounds represented by the formula (I1-b).

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

The acid generator (B) may be either nonionic or ionic. As the nonionic acid generator, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), sulfones (for example, disulfone, Ketosulfone, sulfonyldiazomethane) and the like. Representative examples of the ionic acid generator include onium salts containing onium cations (for example, diazonium salts, phosphonium salts, sulfonium salts, and iodonium salts). Examples of the anion of the onium salt include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

Examples of the acid generator (B) include JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, and JP-A-63-163452. JP-A-62-153853, JP-A-63-146029, U.S. Pat. No. 3,779,778, U.S. Pat. No. 3,849,137, German Patent 3914407, European Patent 126,712, etc. The compounds capable of generating an acid by the radiation described in 1. can be used. 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 kinds.

The acid generator (B) is preferably a fluorine-containing acid generator, and more preferably a salt represented by the formula (B1) (hereinafter sometimes referred to as “acid generator (B1)”, provided that the salt (I ) Is excluded.).
[In the formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a C 1-6 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 with —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 - is, -O -, - S (O ) 2 - or -CO- may be replaced with.
Z1 ⁺ represents an organic cation. ]

^Examples of the perfluoroalkyl group represented by Q ^b1 and Q ^b2 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group and A perfluorohexyl group etc. are mentioned.
It is preferable that Q ^b1 and Q ^b2 are each independently a fluorine atom or a trifluoromethyl group, and it is more preferable that both are a fluorine atom.

Examples of the divalent saturated hydrocarbon group for L ^b1 include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. 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 , Straight chain 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;
Ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- A branched alkanediyl group such as a 1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, a 2-methylbutane-1,4-diyl group;
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 and the like. Valent alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbon such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group and adamantane-2,6-diyl group Groups and the like.

Examples of the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced with —O— or —CO— include, for example, formula (b1-1) to formula (b1-3). And a group represented by any of the above. 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, * and * * Represents a bond, and * represents a bond with -Y.

[In the formula (b1-1),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, -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 the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, -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 the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, -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.
* And ** represent a bond, and * represents a bond with Y. ]

In the group represented by the formula (b1-1) ~ formula (b1-3), -CH ₂ contained in a saturated hydrocarbon radicals - if is replaced by -O- or -CO-, replacing the previous carbon Let the number be the carbon number of the saturated hydrocarbon group.
Examples of the divalent saturated hydrocarbon group include those similar to the divalent saturated hydrocarbon group of L ^b1 .

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

The group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced with —O— or —CO— is represented by the formula (b1-1) or the formula (b1-3). Are preferred groups.
Examples of the group represented by the formula (b1-1) include groups represented by the formulas (b1-4) to (b1-8).
[In the formula (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In formula (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced with —O— or —CO—.
L ^b10 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with 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 divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b12 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. ..
However, the total carbon number of L ^b11 and L ^b12 is 21 or less.
In formula (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group is replaced with —O— or —CO—. Good.
L ^b15 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with 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 with —O— or —CO—.
L ^b17 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. ..
However, the total carbon number of L ^{b16 to} L ^b18 is 19 or less.
* And ** represent a bond, and * represents a bond with Y. ]
L ^b8 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b9 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b10 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b11 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b12 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b13 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b14 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b15 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b16 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b17 is preferably a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b18 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

Examples of the group represented by the formula (b1-3) include groups represented by the formulas (b1-9) to (b1-11).
[In formula (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Good. —CH ₂ — contained in the alkylcarbonyloxy group may be replaced by —O— or —CO—, and the hydrogen atom contained in the alkylcarbonyloxy group may be replaced by a hydroxy group.
However, the total carbon number of L ^b19 and L ^b20 is 23 or less.
In formula (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Good. —CH ₂ — contained in the alkylcarbonyloxy group may be replaced by —O— or —CO—, and the hydrogen atom contained in the alkylcarbonyloxy group may be replaced by a hydroxy group.
However, the total carbon number of L ^b21 , L ^b22 and L ^b23 is 21 or less.
* And ** represent a bond, and * represents a bond with Y. ]
In formula (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Good. —CH ₂ — contained in the alkylcarbonyloxy group may be replaced by —O— or —CO—, and the hydrogen atom contained in the alkylcarbonyloxy group may be replaced 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 the saturated hydrocarbon group is replaced with 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 an acetyloxy group, a propionyloxy group, a butyryloxy group, a cyclohexylcarbonyloxy group and an adamantylcarbonyloxy group.

The following are mentioned as a group represented by a formula (b1-4).

Examples of the group represented by the formula (b1-5) include groups below.

Examples of the group represented by the formula (b1-6) include groups below.

Examples of the group represented by the formula (b1-7) include groups below.
(* and ** represent a bond, and * represents a bond with Y.)

Examples of the group represented by the formula (b1-8) include groups below.

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

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

Examples of the group represented by the formula (b1-10) include groups below.

Examples of the group represented by the formula (b1-11) include groups below.

Examples of the alicyclic hydrocarbon group represented by Y include groups represented by formula (Y1) to formula (Y11) and formula (Y36) to formula (Y38).
Is -O - - -CH ₂ contained in the alicyclic hydrocarbon group represented by _{Y, - S (O) 2} - or replaced by -CO-, to the number it may be one, even in two or more Good. Examples of such a group include groups represented by formula (Y12) to formula (Y35) and formula (Y39) to formula (Y41).
The alicyclic hydrocarbon group represented by Y is preferably formula (Y1) to formula (Y20), formula (Y26), formula (Y27), formula (Y30), formula (Y31), formula (Y39). To a group represented by formula (Y41), more preferably formula (Y11), formula (Y15), formula (Y16), formula (Y20), formula (Y26), formula (Y27), formula A group represented by (Y30), formula (Y31), formula (Y39) or formula (Y40), more preferably formula (Y11), formula (Y15), formula (Y20), formula (Y26), formula It is a group represented by (Y27), formula (Y30), formula (Y31), formula (Y39) or formula (Y40).
When the alicyclic hydrocarbon group represented by Y is a spiro ring having an oxygen atom such as formula (Y28) to formula (Y35), formula (Y39) or formula (Y40), it is between two oxygen atoms. The alkanediyl group of is preferably one or more fluorine atom. Further, it is preferable that, in the alkanediyl group contained in the ketal structure, the methylene group adjacent to the oxygen atom is not substituted with a fluorine atom.

As the 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} represents 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 combination thereof, and ja represents an integer of 0 to 4. The alkyl group and the alicyclic carbon group —CH ₂ — contained in the hydrogen group may be replaced by —O—, —S(O) ₂ — or —CO—, and the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon are substituted. The hydrogen atom contained in the group may be replaced with a hydroxy group or a fluorine atom).
As the 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 with a hydroxy group, an alicyclic group having 3 to 16 carbon atoms Hydrocarbon group, alkoxy group having 1 to 12 carbon atoms, aromatic hydrocarbon group having 6 to 18 carbon atoms, aralkyl group having 7 to 21 carbon atoms, alkylcarbonyl group having 2 to 4 carbon atoms, glycidyloxy group, -( ^{_{CH 2) ja -CO-O-}} R b1 group or _{- (CH 2) ja -O-} CO-R b1 group ^{(wherein, R b1} represents 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 combination thereof, and ja represents an integer of 0 to 4. The alkyl group and the alicyclic carbon group —CH ₂ — contained in the hydrogen group may be replaced by —O—, —S(O) ₂ — or —CO—, and the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon are substituted. The hydrogen atom contained in the group may be replaced with a hydroxy group or a fluorine atom).

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a norbornyl group and an adamantyl group.
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, naphthyl group, anthryl group, biphenyl group and phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and examples of the aromatic hydrocarbon group having a chain hydrocarbon group include a tolyl group, a xylyl group, and a cumenyl group. , Mesityl group, p-ethylphenyl group, p-tert-butylphenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group and the like, and aromatic having an alicyclic hydrocarbon group. Examples of the hydrocarbon group include p-cyclohexylphenyl group and p-adamantylphenyl group.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group, an octyl group and a nonyl group. Group, decyl group, undecyl group, dodecyl group and the like.
Examples of the alkyl group substituted with a hydroxy group include hydroxyalkyl groups such as hydroxymethyl group and hydroxyethyl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group and a naphthylethyl group.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group and a butyryl group.

Examples of Y include the following.

Y is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and more preferably an adamantyl group which may have a substituent. 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 the formula (B1-A-1) to the formula (B1-A-55) [hereinafter, anion (B1-A depending on the formula number -1)" and so on. ] Are preferable, Formula (B1-A-1)-Formula (B1-A-4), Formula (B1-A-9), Formula (B1-A-10), Formula (B1-A-24)-Formula (B1-A-33), Formula (B1-A-36) to Formula (B1-A-40), Formula (B1-A-47) to Formula (B1-A-55). Anions are more preferred.

Here, R ^{i2 to} R ⁱ⁷ are each independently, for example, an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group. R ⁱ⁸ is formed by, for example, a chain hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or a combination thereof. Group, more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group. L ^A41 is a single bond or an alkanediyl group having 1 to 4 carbon atoms. Q ^b1 and Q ^b2 have the same meanings as described above.
Specific examples of the anion in the salt represented by the formula (B1) include the anions described in JP 2010-204646 A.

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). ) To formula (B1a-34) are preferred.

Examples of Z1 ⁺ organic cations include organic onium cations, organic sulfonium cations, organic iodonium cations, organic ammonium cations, benzothiazolium cations, and organic phosphonium cations. Among these, organic sulfonium cations and organic iodonium cations are preferable, and aryl sulfonium cations are more preferable.
Examples of Z1 ⁺ in the formula (B1) include those similar to the cation (I) in the salt (I).

The acid generator (B) is a combination of the above-mentioned anion and the above-mentioned organic cation, and these can be arbitrarily combined. The acid generator (B) is preferably the formula (B1a-1) to the formula (B1a-3), the formula (B1a-7) to the formula (B1a-16), the formula (B1a-18), the formula (B1a-). 19) and a combination of the anion represented by any of the formulas (B1a-22) to (B1a-34) and the cation (b2-1) or the cation (b2-3).

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

When the salt (I) and the acid generator (B) are contained as the acid generator, the ratio of the contents of the salt (I) and 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, and further preferably 10:90 to 90. :10 and particularly preferably 15:85 to 85:15.
In the resist composition of the present invention, the total content of the acid generators is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 3 parts by mass or more with respect to 100 parts by mass of the resin (A) described below. It is 35 parts by mass or less.

<Resist composition>
The resist composition of the present invention contains an acid generator containing 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 by contact with an acid, and the constitutional unit has a hydrophilic group (for example, a hydroxy group or a carboxy group). Means a group that is converted to a unit.
The resist composition of the present invention preferably contains a quencher such as a salt that generates an acid having a weaker acidity than the acid generated from the acid generator (hereinafter sometimes referred to as “quencher (C)”). , A solvent (hereinafter sometimes referred to as “solvent (E)”) is preferably contained.

<Resin (A)>
The resin (A) 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). Examples of the structural unit other than the structural unit (a1) include structural units having no acid labile group (hereinafter sometimes referred to as “structural unit (s)”), structural unit (a1) and structural unit (s). A structural unit (for example, a structural unit having a halogen atom described later (hereinafter sometimes referred to as “structural unit (a4)”) and a structural unit having a non-eliminating hydrocarbon group described later (hereinafter referred to as “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 formula (1) (hereinafter, also referred to as group (1)) and/or a group represented by formula (2) (hereinafter, group (2 )) is preferable.
[In Formula (1), R ^a1 , R ^a2, and R ^a3 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group in which these are combined. That is, R ^a1 and R ^a2 are bonded to each other to form an alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
ma and na each independently represent 0 or 1, and at least one of ma and na represents 1.
* Represents a bond. ]
[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′ are bonded to each other to form a heterocyclic group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded and X, and are included in the hydrocarbon group and the heterocyclic group. CH ₂ - may be replaced by -O- or -S-.
X represents an oxygen atom or a sulfur atom.
na' represents 0 or 1.
* Represents a bond. ]

^Examples of the alkyl group for R ^a1 , R ^a2 and R ^a3 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group and an octyl group.
The alicyclic hydrocarbon group for R ^a1 , R ^a2 and R ^a3 may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as 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 bond). The alicyclic hydrocarbon group of R ^a1 , R ^a2 and R ^a3 preferably has 3 to 16 carbon atoms.
Examples of the group in which an alkyl group and an alicyclic hydrocarbon group are combined include, for example, a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group, and norbornyl. Examples thereof include an ethyl group.
Preferably, ma is 0 and na is 1.
When R ^a1 and R ^a2 are bonded to each other to form an alicyclic hydrocarbon group, -C(R ^a1 )(R ^a2 )(R ^a3 ) includes the following groups. The alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents a bond with -O-.

Examples of the hydrocarbon group for R ^{a1 ′} , R ^{a2 ′} and R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group and a group formed by combining these.
Examples of the alkyl group and alicyclic hydrocarbon group include the same groups as those mentioned for R ^a1 , R ^a2 and R ^a3 .
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, naphthyl group, anthryl group, biphenyl group and phenanthryl group.
Examples of the combined group include a group in which the above alkyl group and an alicyclic hydrocarbon group are combined (for example, a cycloalkylalkyl group), an aralkyl group such as a benzyl group, and an aromatic hydrocarbon group having an alkyl group (p-methyl group). 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 Examples thereof include aromatic hydrocarbon groups (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.) and aryl-cycloalkyl groups such as phenylcyclohexyl group.
When R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a heterocyclic group with the carbon atom to which they are bonded and X, —C(R ^{a1 ′} )(R ^{a2 ′} )—X—R ^{a3 ′} is: The following groups may be mentioned. * Represents a bond.
At least one of R ^{a1 ′} and R ^{a2 ′} is preferably a hydrogen atom.
na′ is preferably 0.

Examples of the group (1) include the following groups.
A group in which R ^a1 , R ^a2, and R ^a3 in the formula (1) are alkyl groups, ma=0 and na=1. The group is preferably a tert-butoxycarbonyl group.
In the formula (1), R ^a1 and R ^a2 together with the carbon atom to which they are bonded form an adamantyl group, R ^a3 is an alkyl group, ma=0 and na=1. ..
In the formula (1), R ^a1 and R ^a2 are each independently an alkyl group, R ^a3 is an adamantyl group, ma=0, and na=1.
Specific examples of the group (1) include the following groups. * Represents a bond.

Specific examples of the group (2) include the following groups. * Represents a bond.

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

The structural unit derived from the (meth)acrylic monomer having the group (1) is preferably a structural unit represented by the formula (a1-0) (hereinafter sometimes referred to as the structural unit (a1-0)). , The structural unit represented by the formula (a1-1) (hereinafter sometimes referred to as the structural unit (a1-1)) or the structural unit represented by the formula (a1-2) (hereinafter, the structural unit (a1- 2) may be mentioned). More preferably, it is at least one structural unit selected from the group consisting of structural unit (a1-1) and structural unit (a1-2). These may be used alone or in combination of two or more.
[In Formula (a1-0), Formula (a1-1), and Formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent -O- or *-O-(CH ₂ ) _k1- CO-O-, k1 represents any integer of 1 to 7, and * represents Represents a bond with -CO-.
R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 each independently ^represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these.
R ^a6 and R ^a7 each independently represent 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 0-10.
n1′ represents an 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 oxygen atoms or *—O—(CH ₂ ) _k01 —CO—O— (however, k01 is preferably an integer of 1 to 4, more preferably Is 1.), more preferably an oxygen atom.
Examples of the alkyl group in R ^a02 , R ^a03 , R ^a04 , R ^a6, and R ^a7 , the alicyclic hydrocarbon group, and a group in which these groups are combined are the groups listed for R ^a1 , R ^a2, and R ^a3 in the formula (1). The same groups as mentioned above can be mentioned.
The alkyl group in R ^a02 , R ^a03 , and R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
The alkyl group in R ^a6 and R ^a7 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group or an isopropyl group, and further preferably an ethyl group or an isopropyl group.
The alicyclic hydrocarbon group of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 preferably has 5 to 12 carbon atoms, and more preferably 5 to 10 carbon atoms.
The group in which an alkyl group and an alicyclic hydrocarbon group are combined preferably has a total carbon number of 18 or less in which these alkyl groups and an alicyclic hydrocarbon group are combined.
R ^a02 and R ^a03 are 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 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.

Examples of the structural unit (a1-0) include structural units represented by any of the formulas (a1-0-1) to (a1-0-12) and R ^a01 in the structural unit (a1-0). Structural units in which the corresponding methyl groups are replaced by hydrogen atoms are mentioned, and structural units represented by any of formula (a1-0-1) to formula (a1-0-10) are preferred.

Examples of the structural unit (a1-1) include structural units derived from the monomers described in JP2010-204646A. Among them, the structural unit represented by any of the formulas (a1-1-1) to (a1-1-4) and the methyl group corresponding to R ^a4 in the structural unit (a1-1) were replaced with hydrogen atoms. The structural unit is preferable, and the structural unit represented by any of the formulas (a1-1-1) to (a1-1-4) is more preferable.

The structural unit (a1-2) corresponds to the structural unit represented by any of the formulas (a1-2-1) to (a1-2-6) and R ^a5 in the structural unit (a1-2). A structural unit in which a methyl group is replaced with a hydrogen atom can be given, and a structural unit represented by any one of formula (a1-2-2), formula (a1-2-5) and formula (a1-2-6) is 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 thereof is the total structure of the resin (A). It 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 even more preferably 100% by mol of the unit. It is 30 to 70 mol %.

Examples of the structural unit having the group (2) in the structural unit (a1) include structural units represented by the formula (a1-4) (hereinafter sometimes referred to as “structural unit (a1-4)”). ..
[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 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 alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl It represents an oxy group or a methacryloyloxy group.
la represents an integer of 0 to 4. When la is 2 or more, a plurality of R ^a33 may be the same 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 2 to 20 carbon atoms with —C—O— to which they are bonded, and —CH ₂ — contained in the hydrocarbon group and the divalent hydrocarbon group is — It may be replaced with 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, further 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.
As the alkyl group having 1 to 6 carbon atoms which may have a halogen atom, 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 a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group and a hexyloxy group. Among them, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further preferable.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group and a butyryl group.
Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group and a butyryloxy group.
As the hydrocarbon group for R ^a34, R ^a35 and R ^a36, an alkyl group, an alicyclic hydrocarbon group, aromatic hydrocarbon group and a group formed by combining these.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group and an octyl group.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopentyl 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).
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, naphthyl group, anthryl group, biphenyl group and phenanthryl group.
Examples of the combined group include a group in which the above alkyl group and an alicyclic hydrocarbon group are combined (for example, a cycloalkylalkyl group), an aralkyl group such as a benzyl group, and an aromatic hydrocarbon group having an alkyl group (p-methyl group). 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 Examples thereof include aromatic hydrocarbon groups (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.) and aryl-cycloalkyl groups such as phenylcyclohexyl group. In particular, Ra ³⁶ is 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. Are listed.

In formula (a1-4), R ^a32 is preferably a hydrogen atom.
As R ^a33 , 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. The group formed is 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 in R ^a36 and the alicyclic hydrocarbon group are preferably unsubstituted. The aromatic hydrocarbon group for 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.

Examples of the structural unit (a1-4) include structural units derived from the monomers described in JP2010-204646A. Preferably, hydrogen atom corresponding to the structural units and ^{R a32} each represented by formula (a1-4-1) ~ formula (a1-4-12) are exemplified a structural unit replacing a methyl group, more preferably , Structural units represented by formula (a1-4-1) to formula (a1-4-5) and formula (a1-4-10), respectively.

When the resin (A) has the structural unit (a1-4), its content is preferably 10 to 95 mol% relative to the total of all structural units of the resin (A), and preferably 15 to 90. It is more preferably mol%, further preferably 20 to 85 mol%, further preferably 20 to 70 mol%, and particularly preferably 20 to 60 mol%.

Examples of the structural unit derived from the (meth)acrylic monomer having the group (2) also include a structural unit represented by the formula (a1-5) (hereinafter sometimes referred to as “structural unit (a1-5)”). To 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 bond to L ^51.
L ^51, L ^52, L ⁵³ and L ⁵⁴ each independently represents -O- or -S-.
s1 represents an integer of 1 to 3.
s1′ represents an integer of 0 to 3.

Examples of the halogen atom include a fluorine atom and a chlorine atom, and a fluorine atom is preferable.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include 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 trifluoromethyl. Groups.
In formula (a1-5), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
It is preferable that one of L ⁵² and L ⁵³ is —O— and the other is —S—.
s1 is preferably 1.
s1′ is preferably an integer of 0-2.
Z ^a1 is preferably a single bond or *—CH ₂ —CO—O—.

Examples of the structural unit (a1-5) include structural units derived from monomers described in JP 2010-61117 A. Of these, structural units represented by formula (a1-5-1) to formula (a1-5-4) are preferable, and each of them is represented by formula (a1-5-1) or formula (a1-5-2). Structural units are more preferred.

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

The structural unit (a1) also includes the following structural units.

When the resin (A) contains the structural units such as (a1-3-1) to (a1-3-7) described above, the content is 10 to 10 with respect to all the structural units of the resin (A). 95 mol% is preferable, 15-90 mol% is more preferable, 20-85 mol% is further more preferable, 20-70 mol% is further more preferable, 20-60 mol% is especially preferable.

<Structural unit (s)>
The structural unit (s) is derived from a monomer having no acid labile group (hereinafter sometimes referred to as “monomer (s)”). As the monomer that leads to the structural unit (s), a monomer that does not have an acid labile group known in the resist field can be used.
The structural unit (s) preferably has a hydroxy group or a lactone ring. A structural unit having a hydroxy group and having no acid labile group (hereinafter sometimes referred to as "structural unit (a2)") and/or a lactone ring and having no acid labile group When 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 contained in the structural unit (a2) may be an alcoholic hydroxy group or a phenolic hydroxy group.
When a resist pattern is produced from the resist composition of the present invention, when a high energy ray such as KrF excimer laser (248 nm), electron beam or EUV (ultra-ultraviolet light) is used as an exposure light source, it is used as a structural unit (a2). It is preferable to use the structural unit (a2) having a phenolic hydroxy group. When using an ArF excimer laser (193 nm) or the like, the structural unit (a2) is preferably a structural unit (a2) having an alcoholic hydroxy group, and the structural unit (a2-1) described later is more preferable. preferable. As the structural unit (a2), one type may be included alone, or two 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 the 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 alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, or acryloyl. It 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 bond to the carbon atom to which -R ^a50 binds.
A ^a52 represents an alkanediyl group having 1 to 6 carbon atoms.
X ^a51 and X ^a52 each independently represent —O—, ^—CO —O— or —O—CO—.
nb represents 0 or 1.
mb represents the integer in any one of 0-4. When mb is any integer greater than or equal to 2, some R ^<a51> may mutually be same or different. ]

^Examples of the halogen atom for R ^a50 include a fluorine atom, a chlorine atom and a bromine atom.
^Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom in R ^a50 include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, 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, 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group and perfluorohexyl group Groups.
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, further preferably a hydrogen atom or a methyl group.
^Examples of the alkyl group for R ^a51 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group.
^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. An alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further preferable.
^Examples of the alkylcarbonyl group for R ^a51 include an acetyl group, a propionyl group and a butyryl group.
^Examples of the alkylcarbonyloxy group for R ^a51 include an acetyloxy group, a propionyloxy group and a butyryloxy group.
R ^a51 is preferably a methyl group.

^{* -X a51 - (A a52 -X} a52) nb - The, * - O -, * - CO-O -, * - O-CO -, * - CO-O-A a52 -CO-O-, *-O-CO-A ^a52 -O-, *-O-A ^a52 -CO-O-, *-CO-O-A ^a52 -O- ^CO- , *-O-CO-A ^a52 -O-CO -, and the like. Among them, *-CO-O-, *-CO-O- ^Aa52- CO-O- or *-O- ^Aa52- CO-O- is preferable.

Examples of the alkanediyl group include 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 and the like.
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. _2- CO-O- is more preferred, and a single bond or *-CO-O- is even more preferred.

mb is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.
The hydroxy group is preferably bonded to the ortho position or para position of the benzene ring, and more preferably to the para position.

Examples of the structural unit (a2-A) include structural units derived from the monomers described in JP2010-204634A and JP2012-12577A.
As the structural unit (a2-A), the structural unit represented by the formula (a2-2-1) to the formula (a2-2-6) and the formula (a2-2-1) to the formula (a2-2-6). In the structural unit represented by the ^formula (1), a structural unit in which a methyl group corresponding to R ^a50 in the structural unit (a2-A) is replaced with a hydrogen atom is ^exemplified . The structural unit (a2-A) is a structural unit represented by the formula (a2-2-1) or a structural unit represented by the formula (a2-2-3). The structural unit represented by the formula (a2-2-6), the structural unit represented by the formula (a2-2-1), the structural unit represented by the formula (a2-2-3), or the formula (a2-2). In the structural unit represented by -6), the methyl group corresponding to R ^a50 in the structural unit (a2-A) is preferably a structural unit in which a hydrogen atom is replaced.

When the structural unit (a2-A) is contained in the resin (A), the content of the structural unit (a2-A) is preferably 5 to 80 mol% with respect to all structural units, and more preferably It is 10 to 70 mol %, more preferably 15 to 65 mol %, and even more preferably 20 to 65 mol %.
The structural unit (a2-A) can be contained in the resin (A) by, for example, polymerizing the structural unit (a1-4) and then treating with an acid such as p-toluenesulfonic acid. Further, the structural unit (a2-A) can be contained in the resin (A) by polymerizing with acetoxystyrene or the like and then treating with an alkali such as tetramethylammonium hydroxide.

Examples of the structural unit having an alcoholic hydroxy group in the structural unit (a2) include structural units represented by the formula (a2-1) (hereinafter sometimes referred to as “structural unit (a2-1)”).
In formula (a2-1),
L ^a3 is, -O- or _{* -O- (CH 2) k2 -CO} -O- the stands,
k2 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
o1 represents any integer of 0-10.

In formula (a2-1), L ^a3 is preferably —O—, —O—(CH ₂ ) _f1 —CO—O— (wherein f1 represents any integer of 1 to 4). , And more preferably -O-.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, and more preferably 0 or 1.

Examples of the structural unit (a2-1) include structural units derived from the monomers described in JP2010-204646A. The structural unit represented by any one of formula (a2-1-1) to formula (a2-1-6) is preferable, and any one of formula (a2-1-1) to formula (a2-1-4) is preferable. The structural unit represented is more preferable, and the structural unit represented by the formula (a2-1-1) or the formula (a2-1-3) is further preferable.

When the resin (A) contains the structural unit (a2-1), the content thereof is usually 1 to 45 mol%, preferably 1 to 40 mol% with respect to the total structural units of the resin (A). Yes, more preferably 1 to 35 mol%, further preferably 1 to 20 mol%, and even more preferably 1 to 10 mol%.

<Structural unit (a3)>
The lactone ring contained in the structural unit (a3) may be a single ring such as a β-propiolactone ring, a γ-butyrolactone ring, or a δ-valerolactone ring, and is a condensed ring of a monocyclic lactone ring and another ring. But it's okay. 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 the formula (a3-1), the formula (a3-2), the formula (a3-3) or the formula (a3-4). These may be contained alone or in combination of two or more.
[In Formula (a3-1), Formula (a3-2), Formula (a3-3), and 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- is represented.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
* Represents a binding site with the carbonyl group.
R ^a18 , R ^a19 and R ^a20 each independently represent 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.
X ^a3 is, -CH ₂ - represents an or an oxygen atom.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
R ^a22 , R ^a23 and R ^a25 each independently represent a carboxy group, a cyano group or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents any integer of 0-5.
q1 represents an integer of 0 to 3.
r1 represents an integer of 0 to 3.
w1 represents an integer of 0 to 8.
When p1, q1, r1 and/or w1 are 2 or more, a plurality of R ^a21 , R ^a22 , R ^a23 and/or R ^a25 may be the same as or different from each other. ]

Examples of the aliphatic hydrocarbon group for R ^a21 , R ^a22 , R ^a23 and R ^a25 include an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group and a tert-butyl group. To be
Examples of the halogen atom for R ^a24 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
^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 preferably a carbon number of 1 to 4 And an alkyl group are more preferable, and a methyl group or an ethyl group is more preferable.
Examples of the alkyl group having a halogen atom in R ^a24 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, a perfluoro group. Hexyl group, trichloromethyl group, tribromomethyl group, triiodomethyl group and the like can be mentioned.
^Examples of the alkanediyl group in L ^a8 and L ^a9 include 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, Examples thereof include 4-diyl group and 2-methylbutane-1,4-diyl group.

In formulas (a3-1) to (a3-3), L ^{a4 to} L ^a6 are each independently, preferably —O— or *—O—(CH ₂ ) _k3— CO—O—, k3. 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.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are each 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 further preferably a hydrogen atom or a methyl group. Is.
R ^a25 is preferably a carboxy group, a cyano group or a methyl group.
L ^a7 is preferably -O- or *-O-L ^a8 -CO-O-, and more preferably -O-, -O-CH ₂ -CO-O- or -O-C ₂ H ₄ -. It is CO-O-.
w1 is preferably an integer of 0 to 2, and more preferably 0 or 1.
Particularly, the formula (a3-4) is preferably the formula (a3-4)′.
(In the formula, R ^a24 and L ^a7 have the same meanings as described above.)

As the structural unit (a3), a structure derived from the monomer described in JP-A-2010-204646, the monomer described in JP-A-2000-122294, and the monomer described in JP-A-2012-41274. The unit is mentioned. As the structural unit (a3), formula (a3-1-1), formula (a3-1-2), formula (a3-2-1), formula (a3-2-2), formula (a3-3-). 1), the structural unit represented by any of the formula (a3-3-2) and the formula (a3-4-1) to the formula (a3-4-12), and the structural unit represented by the formula (a3-1). ) To formula (a3-4), 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 thereof is usually 5 to 70 mol%, preferably 10 to 65 mol% with respect to the total structural units of the resin (A). , And more preferably 10 to 60 mol %.
In addition, 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 based on the total structural units of the resin (A). Therefore, 5 to 60 mol% is preferable, 5 to 50 mol% is more preferable, and 10 to 50 mol% is further preferable.

<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 having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced with —O— or —CO. ]
Examples of the saturated hydrocarbon group represented by R ⁴² include a chain hydrocarbon group, a monocyclic or polycyclic alicyclic hydrocarbon group, and a group formed by combining these.

Examples of the chain hydrocarbon group include 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 the monocyclic or polycyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups. (* represents a bond) and other polycyclic alicyclic hydrocarbon groups.
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 an -alkanediyl group- Examples thereof include an alicyclic hydrocarbon group, an alicyclic hydrocarbon group, an alkyl group, an alkanediyl group, an alicyclic hydrocarbon group and an alkyl group.

The structural unit (a4) is at least selected from the group consisting of formula (a4-0), formula (a4-1), formula (a4-2), formula (a4-3) and formula (a4-4). A structural unit represented by one may be mentioned.
[In the formula (a4-0),
R ⁵ represents a hydrogen atom or a methyl group.
L ^4a represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^3a represents a perfluoroalkanediyl group having 1 to 8 carbon atoms or a perfluorocycloalkanediyl group having 3 to 12 carbon atoms.
R ⁶ represents a hydrogen atom or a fluorine atom. ]

Examples of the divalent saturated aliphatic hydrocarbon group for L ^4a include 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, propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, etc. A group of alkanediyl groups.
^Examples of the perfluoroalkanediyl group in L ^3a include a difluoromethylene group, a perfluoroethylene group, a perfluoropropane-1,1-diyl group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group and 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, perfluoroheptane-2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane A 2,2-diyl group, a perfluorooctane-3,3-diyl group, a perfluorooctane-4,4-diyl group and the like can be mentioned.
^Examples of the perfluorocycloalkanediyl group in L ^3a include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group and a perfluoroadamantanediyl group.

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

Examples of the structural unit (a4-0) include a structural unit shown below and a structural unit in which a methyl group corresponding to R ⁵ 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 with —O— or —CO—. May be.
A ^a41 represents an ^optionally substituted alkanediyl group having 1 to 6 carbon atoms 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 divalent saturated hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
A ^a43 represents a ^C 1-5 divalent aliphatic hydrocarbon group which may have a single bond or a substituent.
X ^a41 and X ^a42 each independently represent —O—, —CO—, ^—CO —O— or —O—CO—.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less. ]
* Is a bond, and * on the right side is a bond with -O-CO- ^Ra42 . ]

^Examples of the saturated hydrocarbon group for R ^a42 include a chain saturated hydrocarbon group, a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and a group formed by combining these.
As the 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 Are listed.
Examples of the monocyclic or polycyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups. (* represents a bond) and other polycyclic alicyclic saturated hydrocarbon groups.
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 saturated hydrocarbon groups, and an -alkanediyl group. Examples thereof include an alicyclic saturated hydrocarbon group, an alicyclic saturated hydrocarbon group, an alkyl group, an alkanediyl group, an alicyclic saturated hydrocarbon group and an alkyl group.

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

^Examples of the aliphatic hydrocarbon group for A ^a45 include 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 Alkyl groups such as octadecyl group; monocyclic alicyclic hydrocarbon groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group; and decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* represents a bond) and other polycyclic alicyclic hydrocarbon groups.
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 an -alkanediyl group- Examples thereof include an alicyclic hydrocarbon group, an alicyclic hydrocarbon group, an alkyl group, an alkanediyl group, an alicyclic hydrocarbon group and an alkyl group.

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

When R ^a42 is an aliphatic hydrocarbon 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 aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
^Xa44 represents **-O-CO- or **-CO-O- (** represents a bond with ^Aa46 ).
A ^a47 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
However, the total number of carbon atoms of A ^a46 , A ^a47, and X ^a44 is 18 or less, and at least one of A ^a46 and A ^a47 has at least one halogen atom.
* Represents a bond with the carbonyl group. ]

1-6 are preferable and, as for carbon number of the aliphatic hydrocarbon group of ^Aa46 , 1-3 are more preferable.
The aliphatic hydrocarbon group of A ^a47 preferably has 4 to 15 carbon atoms, more preferably 5 to 12 carbon atoms, and A ^a47 is 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 bond with the carbonyl group).

The alkanediyl group for A ^a41 is a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group. A linear alkanediyl group such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,2-diyl group, 1-methylbutane-1,4-diyl group, Examples thereof include branched alkanediyl groups such as 2-methylbutane-1,4-diyl group.
^Examples of the substituent in the alkanediyl group of A ^a41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
A ^a41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and further preferably an ethylene group.

The divalent saturated hydrocarbon group represented by A ^a42 , A ^a43 and A ^{a44 in} the group represented by the formula (a-g1) is a linear or branched alkanediyl group and a monocyclic divalent alicyclic group. Examples thereof include a hydrocarbon group, and a group formed by combining an alkanediyl group and a divalent alicyclic hydrocarbon group. Specifically, a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a 1-methylpropane-1,3-diyl group, Examples thereof include 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.
^Examples of the substituent of the divalent saturated hydrocarbon group represented by A ^a42 , A ^a43 and A ^a44 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
s is preferably 0.

^{Examples of the} group represented by the formula (a-g1) in which X ^a42 is —O—, ^—CO— , ^—CO —O— or —O—CO— include the following groups. In the following examples, * and ** each represent a bond, and ** is a bond with -O-CO- ^Ra42 .

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

As the 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 an alkanediyl group having 1 to 6 carbon atoms, and —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—.
R ^f6 represents a saturated hydrocarbon group having a fluorine atom having 1 to 20 carbon atoms.
However, the upper limit of the total carbon number of L ⁴⁴ and R ^f6 is 21. ]

^Examples of the alkanediyl group having 1 to 6 carbon atoms for L ⁴⁴ include the same groups as those exemplified for the alkanediyl group for A ^a41 .
Examples of the saturated hydrocarbon group for R ^f6 include the same groups as those exemplified for R ^a42 .
As the alkanediyl group having 1 to 6 carbon atoms in L ^44, an alkanediyl group having 2 to 4 carbon atoms is preferable, and an ethylene group is more preferable.

Examples of the structural unit represented by the formula (a4-2) include structural units represented by the formulas (a4-1-1) to (a4-1-11). 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 included as the structural unit represented by the formula (a4-2).

Examples of the structural unit (a4) include structural units represented by the formula (a4-3).
[In the formula (a4-3),
R ^f7 represents a hydrogen atom or a methyl group.
L ⁵ represents an alkanediyl group having 1 to 6 carbon atoms.
A ^f13 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, which may have a fluorine atom.
^Xf12 represents *-O-CO- or *-CO-O- (* represents a bond with ^Af13 ).
A ^f14 represents a saturated hydrocarbon group having 1 to 17 carbon atoms, which may have a fluorine atom.
However, at least one of A ^f13 and A ^f14 has a fluorine atom, and the upper limit of the total carbon number of L ⁵ , A ^f13 and A ^f14 is 20. ]

^Examples of the alkanediyl group for L ⁵ include the same groups as those exemplified for the alkanediyl group in the divalent saturated hydrocarbon group for A ^a41 .
The divalent saturated hydrocarbon group which may have a fluorine atom in A ^f13 is preferably a divalent aliphatic saturated hydrocarbon group which optionally has a fluorine atom and a fluorine atom. Is a divalent alicyclic saturated hydrocarbon group, and more preferably a perfluoroalkanediyl group.
Examples of the divalent aliphatic hydrocarbon group which may have a fluorine atom include alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group and pentanediyl group; difluoromethylene group, perfluoroethylene group, perfluoro group. Examples thereof include a perfluoroalkanediyl group such as a propanediyl group, a perfluorobutanediyl group, and a perfluoropentanediyl group.
The divalent alicyclic 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 Alkyl group, cyclopropylmethyl group, cyclopropyl group, cyclobutylmethyl group, cyclopentyl group, cyclohexyl group, perfluorocyclohexyl group, adamantyl group, adamantylmethyl group, adamantyldimethyl group, norbornyl group, norbornylmethyl group, perfluoroadamantyl group , Perfluoroadamantylmethyl 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 divalent chain hydrocarbon group having 1 to 6 carbon atoms and a divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, More preferably, a divalent chain hydrocarbon group of 2 to 3 is used.
The saturated hydrocarbon group of A ^f14 is preferably a group containing a chain hydrocarbon group having 3 to 12 carbon atoms and an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and a chain hydrocarbon group having 3 to 10 carbon atoms. And a group containing an alicyclic hydrocarbon group having 3 to 10 carbon atoms are more preferable. Among them, A ^f14 is preferably a group containing an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group and an adamantyl group.

Examples of the structural unit represented by the formula (a4-3) include structural units represented by the formula (a4-1'-1) to the formula (a4-1'-11). 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 included as the structural unit represented by the formula (a4-3).

The structural unit (a4) also includes a structural unit represented by the formula (a4-4).
[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.
j1 to j5 each independently represent an integer of 1 to 6.
R ^f22 represents a C 1-10 saturated hydrocarbon group having a fluorine atom. ]

^Examples of the saturated hydrocarbon group of R ^f22 include the same as the saturated hydrocarbon group represented by R ^a42 . R ^f22 is preferably a ^C 1-10 alkyl group having a fluorine atom or a C 1-10 alicyclic hydrocarbon group having a fluorine atom, more preferably a C 1-10 alkyl group having a fluorine atom. Preferably, a C 1-6 alkyl group having a fluorine atom is more preferable.

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

As the structural unit represented by the formula (a4-4), for example, in the following structural unit and the structural unit represented by 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 are included.

When the resin (A) has the structural unit (a4), the content thereof is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, based on all the structural units of the resin (A). It is more preferably from 10 to 10 mol %.

<Structural unit (a5)>
Examples of the non-eliminating hydrocarbon group contained in the structural unit (a5) include groups having a linear, branched or cyclic hydrocarbon group. Among them, the structural unit (a5) is preferably a group having an alicyclic hydrocarbon group.
Examples of the structural unit (a5) include structural units represented by the formula (a5-1).
[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 the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms. ..
L ⁵⁵ represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced with —O— or —CO—. .. ]

The alicyclic hydrocarbon group for R ⁵² may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group. Examples of the polycyclic alicyclic hydrocarbon group include an adamantyl group 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 an ethylhexyl group.
Examples of the alicyclic hydrocarbon group having a substituent include a 3-methyladamantyl group.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.
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. Examples of the monocyclic alicyclic saturated hydrocarbon group include cycloalkanediyl groups such as cyclopentanediyl group and cyclohexanediyl group. 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— are, for example, formula (L1-1) to formula (L1-4). The groups represented may be mentioned. In the formulas below, * and ** each represent a bond, and * represents a bond with an oxygen atom.
In formula (L1-1),
X ^x1 is, * - O-CO- or * -CO-O-a represents (* represents a bond 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 C 1 to C 15 divalent saturated aliphatic hydrocarbon group.
However, the total carbon number of L ^x1 and L ^x2 is 16 or less.
In formula (L1-2),
L ^x3 represents a divalent saturated aliphatic hydrocarbon group having 1 to 17 carbon atoms.
L ^x4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
However, the total carbon number of L ^x3 and L ^x4 is 17 or less.
In formula (L1-3),
L ^x5 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^x6 and L ^x7 each independently represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
However, the total carbon number of L ^x5 , L ^x6, and L ^x7 is 15 or less.
In formula (L1-4),
L ^x8 and L ^x9 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 divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond.
L ^x3 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x4 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x5 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methylene group or an ethylene group.
L ^x6 is preferably a single bond or a C 1-8 divalent aliphatic saturated hydrocarbon group, more preferably a methylene group or an ethylene group.
L ^x7 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x8 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond or a methylene group.
L ^x9 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond or a methylene group.
W ^x1 is preferably a divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, more preferably a cyclohexanediyl group or an adamantanediyl group.

Examples of the group represented by the formula (L1-1) include the divalent groups shown below.

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

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

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

L ⁵⁵ is preferably a single bond or a group represented by the formula (L1-1).

Examples of the structural unit (a5-1) include a structural unit shown below and a structural unit in which a methyl group corresponding to R ⁵¹ in the structural unit (a5-1) in the following structural unit is replaced with a hydrogen atom.

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

<Structural unit (II)>
The resin (A) may further contain a structural unit that decomposes upon exposure to generate an acid (hereinafter, may be referred to as “structural unit (II)”. Specific examples of the structural unit (II) include: Include a structural unit described in JP-A-2016-79235, a structural unit having a sulfonate group or a carboxylate group and an organic cation in a side chain or a structural unit having a sulfonio group and an organic anion in a side chain. It is preferable to have.

The structural unit having a sulfonate group or a carboxylate group 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 replaced with —O—, —S— or —CO—. Well, the hydrogen atom contained in the saturated hydrocarbon group may be replaced with 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 with 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 can be mentioned.
Examples of the alkanediyl group having 1 to 8 carbon atoms represented by A ^x1 include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group. , Hexane-1,6-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2, 4-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group, etc. Can be mentioned.
^Examples of the ^optionally substituted perfluoroalkyl group having 1 to 6 carbon atoms in A ^X1 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, and a perfluorotert group. -Butyl group, perfluoropentyl group, perfluorohexyl group and the like.
Examples of the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by X ^III3 include a linear or branched alkanediyl group and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. However, these may be combined.
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 , A linear alkanediyl group such as dodecane-1,12-diyl group; butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group , A pentane-1,4-diyl group, a branched alkanediyl group such as a 2-methylbutane-1,4-diyl group; a cyclobutane-1,3-diyl group, a cyclopentane-1,3-diyl group, a cyclohexane-1 ,4-diyl group, cyclooctane-1,5-diyl group and other cycloalkanediyl groups; norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane Examples thereof include a divalent polycyclic alicyclic saturated hydrocarbon group such as -2,6-diyl group.
Examples of the —CH ₂ — contained in the saturated hydrocarbon group replaced with —O—, —S— or —CO— include divalent groups represented by formula (X1) to formula (X53). 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, * and ** represent a binding site, and * represents a bond with A ^x1 .

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

Examples of ZA ⁺ in the formula (II-2-A′) include the same as the cation Z1 ^{+ in the} salt represented by the formula (B1).

The structural unit represented by formula (II-2-A′) is preferably the structural unit represented by formula (II-2-A).
Wherein ^(II-2-A), R III3, X III3 and ZA ⁺ are the same as defined above.
z2A represents an integer of 0 to 6.
R ^III2 and R ^III4 each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and when z2A is 2 or more, a plurality of R ^III2 and R ^III4 are the same as each other. It may be different or different.
Q ^a and Q ^b each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group. ]
^Examples of the perfluoroalkyl group having 1 to 6 carbon atoms represented by R ^III2 , R ^III4 , Q ^a and Q ^b are the same as the perfluoroalkyl group having 1 to 6 carbon atoms represented by Q ^b1 described above. ..

The structural unit represented by the formula (II-2-A) is preferably the 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 and ZA ⁺ have the same meanings as described above.
R ^III5 represents a saturated hydrocarbon group having 1 to 12 carbon atoms.
z2A1 represents an integer of 0 to 6.
X ^I2 represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced with —O—, —S— or —CO—. Often, the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a halogen atom or a hydroxy group. ]
Examples of the saturated hydrocarbon group having 1 to 12 carbon atoms represented by R ^III5 include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, 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.
Examples of the divalent saturated hydrocarbon group represented by X ^I2 include those similar to the divalent saturated hydrocarbon group represented by X ^III3 .

As the structural unit represented by the formula (II-2-A-1), the structural unit represented by the formula (II-2-A-2) is more preferable.
Wherein (II-2-A-2 ), R III3, R III5 and ZA ⁺ are the same as defined above.
m and n independently represent 1 or 2. ]

As the structural unit represented by the formula (II-2-A′), for example, the following structural unit, a group corresponding to the methyl group of R ^III3 is a hydrogen atom, a halogen atom (for example, a fluorine atom) or a halogen atom. Examples thereof include structural units in which an alkyl group having 1 to 6 carbon atoms (for example, a trifluoromethyl group) which may be possessed and structural units described in WO 2012/050015 are described. ZA ⁺ represents an organic cation.

The structural unit having a sulfonio group and an organic anion on its side chain is preferably a structural unit represented by the 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 hydrocarbon group having 1 to 18 carbon atoms, and R ^II2 and R ^II3 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
R ^II4 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
A ⁻ represents an organic anion. ]
Examples of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms represented by R ^II1 include a phenylene group and a naphthylene group.
Examples of the hydrocarbon group represented by R ^II2 and R ^II3 include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
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 can be mentioned.
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-. Specific examples thereof include the same as the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by ^XIII3 .

As the structural unit containing a cation in the formula (II-1-1), the structural unit represented by the following and the group corresponding to the methyl group of R ^II4 are replaced with a hydrogen atom, a fluorine atom, trifluoromethyl or the like. Examples include structural units.

Examples of the organic anion represented by A ⁻ include a sulfonate anion, a sulfonylimide anion, a sulfonylmethide anion, and a carboxylate anion. The organic anion represented by A ⁻ is preferably a sulfonate anion, and the sulfonate anion is more preferably an anion contained in the salt represented by the above formula (B1).

A ^- The sulfonyl imide anions represented by, the following may be mentioned.

Examples of the sulfonylmethide anion include the following.

Examples of the carboxylate anion include the following.

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

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

The resin (A) may have a structural unit other than the above structural units, and examples of such a structural unit include structural units well known in the art.

The resin (A) is preferably a resin composed of the structural unit (a1) and the structural unit (s), that is, a copolymer of the monomer (a1) and the 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). At least one selected from the group consisting of structural units (a1-1) and structural units (a1-2) is more preferred.
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 the structural unit (a2-1) or the structural unit (a2-A). The structural unit (a3) is preferably a group consisting of a structural unit represented by the formula (a3-1), a structural unit represented by the formula (a3-2) and a structural unit represented by the formula (a3-4). It is 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 that guides these structural units. be able to. The content of each structural unit of the resin (A) can be adjusted by the amount of the monomer used for 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, further preferably). Is 15,000 or less). In the present specification, the weight average molecular weight is a value determined by gel permeation chromatography under the conditions described in the examples.

<Resin other than resin (A)>
The resist composition of the present invention may use a resin other than the resin (A) in combination.
Examples of the resin other than the resin (A) include a resin containing the structural unit (a4) or the structural unit (a5) (hereinafter sometimes referred to as resin (X)) and the like.
As the resin (X), a resin containing the structural unit (a4) is preferable.
In the resin (X), the content of the structural unit (a4) is preferably 30 mol% or more, and more preferably 40 mol% or more, based on the total of all structural units of the resin (X). More preferably 45 mol% or more.
Examples of the structural unit that the resin (X) may further have include structural units (a1), structural units (a2), structural units (a3) and structural units derived from other known monomers. Above all, the resin (X) is preferably a resin composed of only the structural unit (a4) and/or the structural unit (a5).
Each structural unit constituting the resin (X) 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 that induces these structural units. can do. The content of each structural unit contained in the resin (X) can be adjusted by the amount of the monomer used for polymerization.
The weight average molecular weight of the resin (X) is preferably 6,000 or more (more preferably 7,000 or more) and 80,000 or less (more preferably 60,000 or less). The means for measuring the weight average molecular weight of the resin (X) is the same as that for the resin (A).

When the resist composition of the present invention contains the resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, relative to 100 parts by mass of the resin (A). And 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 or more and 99% by mass or less, and more preferably 90% by mass or more and 99% by mass or less, based on the solid content of the resist composition. When the resin other than the resin (A) is contained, the total content of the resin (A) and the resin other than the resin (A) is 80% by mass or more and 99% by mass or more based on the solid content of the resist composition. The amount is preferably the following, and more preferably 90% by mass or more and 99% by mass or less. In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (E) described below 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 analysis 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 or more and 99.9% by mass or less, preferably 92% by mass or more and 99% by mass or less, and more preferably 94% by mass or more and 99% by mass or less. % Or less. The content of the solvent (E) can be measured by a known analysis means such as liquid chromatography or gas chromatography.

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

<Quencher (C)>
Examples of the quencher (C) include basic nitrogen-containing organic compounds, and salts that 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, more preferably about 0.01 to 3% by mass, based on the solid content of the resist composition.
Examples of basic nitrogen-containing organic compounds include amines and ammonium salts. Examples of 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, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, tri Heptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, Ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris[2-(2-methoxyethoxy)ethyl]amine, tri Isopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3 , 3'-diethyldiphenylmethane, 2,2'-methylenebisaniline, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 1,2-di(2-pyridyl)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 and the like, Diisopropylaniline is preferable, and 2,6-diisopropylaniline is more preferable.

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

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 an acid dissociation constant (pKa). The salt that generates an acid having a weaker acidity than the acid generated from the acid generator (B) is a salt in which the acid dissociation constant of the acid generated from the salt is usually -3<pKa, preferably -1< It is a salt of pKa<7, and more preferably a salt of 0<pKa<5.
As the 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. (Hereinafter, it may be referred to as "weak acid inner salt (D)."), and JP2012-229206A, JP2012-6908A, JP2012-72109A, and JP2011-39502A. The salts described in the publication and JP 2011-191745 A can be mentioned. A weak acid inner salt (D) is preferred.

Examples of the weak acid inner salt (D) include the following salts.

<Other ingredients>
The resist composition of the present invention may contain a component (hereinafter sometimes referred to as “other component (F)”) other than the above components, if necessary. The other component (F) is not particularly limited, and additives known in the resist field, such as a sensitizer, a dissolution inhibitor, a surfactant, a stabilizer, and a dye, can be used.

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

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

The coating of the resist composition on the substrate can be carried out by a commonly used apparatus such as a spin coater. Examples of the substrate include inorganic substrates such as silicon wafers. The substrate may be washed before applying the resist composition, or an antireflection film or the like may be formed on the substrate.

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

The obtained composition layer is usually exposed using an exposure device. The exposure machine may be an immersion exposure machine. As the exposure light source, those that emit laser light in the ultraviolet region such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser) Etc.) that emits harmonic laser light in the far-ultraviolet region or vacuum-ultraviolet region by wavelength-converting the laser light from, etc., electron beams, or those that emit ultra-ultraviolet light (EUV), etc. You can In the present specification, the 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, it may be exposed by direct drawing without using a mask.

The composition layer after exposure is subjected to heat treatment (so-called post-exposure bake) in order to accelerate the deprotection reaction at 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 device using a developing solution. Examples of the developing method include a dipping method, a paddle method, a spray method and a dynamic dispensing method. The development temperature is preferably 5 to 60° C., and the development time is preferably 5 to 300 seconds. A positive resist pattern or a negative resist pattern can be manufactured 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. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl)trimethylammonium hydroxide (commonly called choline). The alkaline developer may contain a surfactant.
After development, it is preferable to wash the resist pattern with ultrapure water, and then remove the water remaining on the substrate and the pattern.

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 the developer.
Examples of the organic solvent 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. Examples include ether solvents; amide solvents such as N,N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
The content of the organic solvent in the organic developer is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and further preferably substantially only the organic solvent.
Among them, the organic developer is preferably a developer containing butyl acetate and/or 2-heptanone. The total content of butyl acetate and 2-heptanone in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and substantially butyl acetate and/or 2 More preferably only heptanone.
A surfactant may be contained in the organic developer. Further, the organic developer may contain a small amount of water.
At the time of development, the development may be stopped by substituting a solvent of a different type from the organic developer.

It is preferable to wash the resist pattern after development with a rinse liquid. The rinse liquid is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, and an alcohol solvent or an ester solvent is preferable.
After the cleaning, it is preferable to remove the rinse liquid 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, It is suitable as a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, and is useful for fine processing of semiconductors.

The present invention will be described more specifically with reference to examples. In the examples, “%” and “part” representing the content or the amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value determined by gel permeation chromatography. The analysis conditions of gel permeation chromatography are as follows.
Column: TSKgel Multipore HXL-M x 3+guard column (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL/min
Detector: RI detector Column temperature: 40℃
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)
The structure of the compound was confirmed by measuring the molecular ion peak using mass spectrometry (LC: Agilent model 1100, MASS: Agilent model LC/MSD). In the following examples, the value of this molecular ion peak is indicated by "MASS".

Example 1: Synthesis of salt represented by formula (I-1)
10 parts of the compound represented by the formula (I-1-a), 3.20 parts of the compound represented by the formula (I-1-b), 100 parts of chloroform and 0.15 part of sulfuric acid are mixed, and at 23° C. After stirring for 30 minutes, the mixture was further stirred at 70°C for 10 hours and cooled to 23°C. To the obtained mixed solution, 30 parts of a 5% sodium hydrogen carbonate aqueous solution was added, and the mixture was stirred at 23° C. for 30 minutes, then liquid-separated, and an organic layer was taken out. After 30 parts of ion-exchanged water was added to the obtained organic layer and the mixture was stirred at 23° C. for 30 minutes, liquid separation was performed and the organic layer was taken out. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, and the concentrated mixture was applied to a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: n-heptane/ethyl acetate=1/1). By fractionating, 8.46 parts of the compound represented by the formula (I-1-c) was obtained.
5 parts of the compound represented by the formula (I-1-c) and 25 parts of acetonitrile were mixed, stirred at 23° C. for 30 minutes, and then cooled to 5° C. A mixed solution of 0.20 parts of sodium borohydride and 2.98 parts of ion-exchanged water was added to the obtained mixed solution, and the mixture was stirred at 5° C. for 2 hours and then concentrated. Chloroform (100 parts) and ion-exchanged water (50 parts) were added to the obtained concentrated mixture, and the mixture was stirred at 23° C. for 30 minutes, then, separated, and the organic layer was taken out. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, and the concentrated mixture was applied to a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: n-heptane/ethyl acetate=1/1). By fractionating, 3.85 parts of the compound represented by the formula (I-1-d) were obtained.
2 parts of the compound represented by the formula (I-1-d), 10 parts of acetonitrile and 1 part of 5% hydrochloric acid were mixed, stirred at 23° C. for 30 minutes, further stirred at 40° C. for 2 hours, and then concentrated. .. The obtained concentrated mixture was fractionated by using a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: n-heptane/ethyl acetate=1/1). 1.01 part of the compound represented by the formula (I-1-e) was obtained.
2.17 parts of the salt represented by the formula (I-1-f) and 20 parts of chloroform were mixed and stirred at 23° C. for 30 minutes. 0.84 parts of the compound represented by the formula (I-1-g) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 2 hours. 0.97 parts of the compound represented by the formula (I-1-e) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 3 hours and then cooled to 23° C. 20 parts of chloroform and 10 parts of a 5% oxalic acid aqueous solution were added to the obtained mixture, and the mixture was stirred at 23° C. for 30 minutes, then, separated, and an organic layer was taken out. Ion-exchanged water (10 parts) was added to the obtained organic layer, the mixture was stirred at 23° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, 20 parts of tert-butyl methyl ether was added to the concentrated residue, the mixture was stirred at 23° C. for 30 minutes, the supernatant was removed, and the mixture was concentrated to give the compound of formula (I-1). 2.48 parts of a salt represented by
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 353.1

Example 2: Synthesis of salt represented by formula (I-2)
6.50 parts of the salt represented by the formula (I-1-f) and 20 parts of chloroform were mixed and stirred at 23° C. for 30 minutes. 2.53 parts of the compound represented by the formula (I-1-g) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 2 hours. 3.57 parts of the compound represented by the formula (I-1-d) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 3 hours and then cooled to 23° C. 70 parts of chloroform and 25 parts of a 5% oxalic acid aqueous solution were added to the obtained mixture, and the mixture was stirred at 23° C. for 30 minutes, then, separated, and the organic layer was taken out. After 30 parts of ion-exchanged water was added to the obtained organic layer and the mixture was stirred at 23° C. for 30 minutes, liquid separation was performed and the organic layer was taken out. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, 10 parts of acetonitrile and 90 parts of tert-butyl methyl ether were added to the concentrated residue, and the mixture was stirred at 23° C. for 30 minutes, then, the supernatant was removed, and the mixture was concentrated by the formula ( 6.24 parts of the salt represented by I-2) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 397.1

Example 3: Synthesis of salt represented by formula (I-20)
9.54 parts of the salt represented by the formula (I-20-a) and 30 parts of chloroform were mixed and stirred at 23° C. for 30 minutes. 3.28 parts of the compound represented by the formula (I-1-d) was added to the obtained mixed solution, and the mixture was further stirred at 23° C. for 8 hours. 30 parts of ion-exchanged water was added to the obtained mixture, and the mixture was stirred at 23° C. for 30 minutes, then, liquid separation was performed, and an organic layer was taken out. 20 parts of a 5% oxalic acid aqueous solution was added to the obtained organic layer, and the mixture was stirred at 23° C. for 30 minutes, then, liquid separation was performed, and the organic layer was taken out. After 30 parts of ion-exchanged water was added to the obtained organic layer and the mixture was stirred at 23° C. for 30 minutes, liquid separation was performed and the organic layer was taken out. This water washing operation was repeated 5 times. After concentrating the obtained organic layer, 3 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentration residue and the mixture was stirred at 23° C. for 30 minutes. 9.69 parts of the salt represented by (I-20) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI(-) Spectrum): M ^- 605.2

Example 4: Synthesis of salt represented by formula (I-141)
2.04 parts of the salt represented by the formula (I-141-f) and 20 parts of chloroform were mixed and stirred at 23° C. for 30 minutes. 0.84 parts of the compound represented by the formula (I-1-g) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 2 hours. 0.97 parts of the compound represented by the formula (I-1-e) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 3 hours and then cooled to 23° C. 20 parts of chloroform and 10 parts of a 5% oxalic acid aqueous solution were added to the obtained mixture, and the mixture was stirred at 23° C. for 30 minutes, then, separated, and an organic layer was taken out. Ion-exchanged water (10 parts) was added to the obtained organic layer, the mixture was stirred at 23° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, 20 parts of tert-butyl methyl ether was added to the concentrated residue, the mixture was stirred at 23° C. for 30 minutes, the supernatant was removed, and the mixture was concentrated to give the compound of the formula (I-141). 2.19 parts of a salt represented by
MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 353.1

Example 5: Synthesis of salt represented by formula (I-142)
6.11 parts of the salt represented by the formula (I-141-f) and 20 parts of chloroform were mixed and stirred at 23° C. for 30 minutes. 2.53 parts of the compound represented by the formula (I-1-g) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 2 hours. 3.57 parts of the compound represented by the formula (I-1-d) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 3 hours and then cooled to 23° C. 70 parts of chloroform and 25 parts of a 5% oxalic acid aqueous solution were added to the obtained mixture, and the mixture was stirred at 23° C. for 30 minutes, then, separated, and the organic layer was taken out. After 30 parts of ion-exchanged water was added to the obtained organic layer and the mixture was stirred at 23° C. for 30 minutes, liquid separation was performed and the organic layer was taken out. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, 10 parts of acetonitrile and 90 parts of tert-butyl methyl ether were added to the concentrated residue, and the mixture was stirred at 23° C. for 30 minutes, then, the supernatant was removed, and the mixture was concentrated by the formula ( 6.39 parts of the salt represented by I-142) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 397.1

Example 6: Synthesis of salt represented by formula (I-3)
10 parts of the compound represented by the formula (I-1-a), 9.13 parts of the compound represented by the formula (I-3-b), 100 parts of chloroform and 0.15 part of sulfuric acid are mixed, and at 23° C. After stirring for 30 minutes, the mixture was further stirred at 70°C for 10 hours and cooled to 23°C. To the obtained mixed solution, 30 parts of a 5% sodium hydrogen carbonate aqueous solution was added, and the mixture was stirred at 23° C. for 30 minutes, then liquid-separated, and an organic layer was taken out. After 30 parts of ion-exchanged water was added to the obtained organic layer and the mixture was stirred at 23° C. for 30 minutes, liquid separation was performed and the organic layer was taken out. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, and the concentrated mixture was applied to a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: n-heptane/ethyl acetate=1/1). By fractionating, 9.43 parts of the compound represented by the formula (I-3-c) were obtained.
7.10 parts of the compound represented by formula (I-3-c) and 25 parts of acetonitrile were mixed, stirred at 23°C for 30 minutes, and then cooled to 5°C. A mixed solution of 0.20 parts of sodium borohydride and 2.98 parts of ion-exchanged water was added to the obtained mixed solution, and the mixture was stirred at 5° C. for 2 hours and then concentrated. Chloroform (100 parts) and ion-exchanged water (50 parts) were added to the obtained concentrated mixture, and the mixture was stirred at 23° C. for 30 minutes, then, separated, and the organic layer was taken out. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, and the concentrated mixture was applied to a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: n-heptane/ethyl acetate=1/1). By fractionating, 4.22 parts of the compound represented by the formula (I-3-d) were obtained.
2.17 parts of the salt represented by the formula (I-1-f) and 20 parts of chloroform were mixed and stirred at 23° C. for 30 minutes. 0.84 parts of the compound represented by the formula (I-1-g) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 2 hours. 1.68 parts of the compound represented by the formula (I-3-d) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 3 hours and then cooled to 23° C. 20 parts of chloroform and 10 parts of a 5% oxalic acid aqueous solution were added to the obtained mixture, and the mixture was stirred at 23° C. for 30 minutes, then, separated, and an organic layer was taken out. Ion-exchanged water (10 parts) was added to the obtained organic layer, the mixture was stirred at 23° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, 20 parts of tert-butyl methyl ether was added to the concentrated residue, the mixture was stirred at 23° C. for 30 minutes, the supernatant was removed, and the mixture was concentrated to give the compound of formula (I-3). 2.68 parts of a salt represented by
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 497.1

Example 7: Synthesis of salt represented by formula (I-15)
2.10 parts of the salt represented by the formula (I-15-f) and 20 parts of chloroform were mixed and stirred at 23° C. for 30 minutes. 0.84 parts of the compound represented by the formula (I-1-g) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 2 hours. 1.68 parts of the compound represented by the formula (I-3-d) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 3 hours and then cooled to 23° C. 20 parts of chloroform and 10 parts of a 5% oxalic acid aqueous solution were added to the obtained mixture, and the mixture was stirred at 23° C. for 30 minutes, then, separated, and an organic layer was taken out. Ion-exchanged water (10 parts) was added to the obtained organic layer, the mixture was stirred at 23° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, 20 parts of tert-butyl methyl ether was added to the concentrated residue, the mixture was stirred at 23° C. for 30 minutes, the supernatant was removed, and the mixture was concentrated to give the compound of formula (I-15). 2.88 parts of a salt represented by
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 527.1

Example 8: Synthesis of salt represented by formula (I-135)
2.37 parts of the salt represented by the formula (I-135-f) and 20 parts of chloroform were mixed and stirred at 23° C. for 30 minutes. 0.84 parts of the compound represented by the formula (I-1-g) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 2 hours. 1.68 parts of the compound represented by the formula (I-3-d) was added to the obtained mixed solution, and the mixture was further stirred at 50° C. for 3 hours and then cooled to 23° C. 20 parts of chloroform and 10 parts of a 5% oxalic acid aqueous solution were added to the obtained mixture, and the mixture was stirred at 23° C. for 30 minutes, then, separated, and an organic layer was taken out. Ion-exchanged water (10 parts) was added to the obtained organic layer, the mixture was stirred at 23° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. The obtained organic layer was concentrated, 20 parts of tert-butyl methyl ether was added to the concentrated residue, the mixture was stirred at 23° C. for 30 minutes, the supernatant was removed, and the mixture was concentrated to give the compound of formula (I-135). 2.79 parts of a salt represented by
MASS (ESI (+) Spectrum): M ⁺ 317.1
MASS (ESI (-) Spectrum): M ^- 527.1

Resin Synthesis The compounds (monomers) used for the synthesis of resin (A) are shown below. Hereinafter, these compounds are referred to as “monomer (a1-1-3)” and the like according to the formula numbers.

Synthesis Example 1: Synthesis of Resin A1 As the monomer, a monomer (a1-1-3), a monomer (a1-2-5), a monomer (a2-1-1) and a monomer (a3-1-1) are used. The molar ratio [monomer (a1-1-3):monomer (a1-2-5):monomer (a2-1-1):monomer (a3-1-1)] was 14:45:2.5:38. The mixture was mixed so as to be 5, and propylene glycol monomethyl ether acetate in an amount of 1.5 times the total amount of the monomers was added to obtain a solution. To this solution, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators in an amount of 1 mol% and 3 mol% based on the total amount of the monomers, respectively, and these were heated at 73° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of a mixed solvent of methanol/water to precipitate a resin, and the resin was filtered. The resin thus obtained is again dissolved in propylene glycol monomethyl ether acetate, the solution obtained is poured into a mixed solvent of methanol/water to precipitate the resin, and the resin is filtered again to perform reprecipitation operation twice, and a weight average is obtained. Resin A1 having a molecular weight of 7.9×10 ³ was obtained with a yield of 88%. This resin A1 has the following structural units.

Synthesis Example 2: Synthesis of Resin X1 The monomer (a4-1-4) was used as a monomer, and methyl isobutyl ketone in an amount 1.5 times as much as the total amount of the monomer was added to obtain a solution. To this solution, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators in an amount of 0.7 mol% and 2.1 mol% based on the total amount of the monomers, respectively, and these were added at 75°C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol/water mixed solvent to precipitate a resin, and the resin was filtered to obtain a resin X1 having a weight average molecular weight of 1.7×10 ⁴ with a yield of 77%. This resin X1 has the following structural units.

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

<Resin>
A1, X1: Resin A1, Resin X1
<Salt (I)>
I-1: Salt represented by formula (I-1) I-2: Salt represented by formula (I-2) I-3: Salt represented by formula (I-3) I-15: Formula Salt represented by (I-15) I-20: Salt represented by formula (I-20) I-135: Salt represented by formula (I-135) I-141: Formula (I-141) A salt represented by formula I-142: a salt represented by formula (I-142) <acid generator>
IX-1: salt represented by formula (IX-1) (synthesized according to the example of JP 2007-161707 A)
IX-2: a salt represented by the formula (IX-2) (synthesized according to the example of JP2007-145824A).
IX-3: Salt represented by the formula (IX-3) (synthesized according to the example of JP-A-2018-048106)
IX-4: Salt represented by Formula (IX-4) (synthesized according to the example of JP-A-2018-048106)
<Quencher (C)>
D1: (manufactured by Tokyo Chemical Industry Co., Ltd.)
<Solvent>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 3.5 parts

<Production of resist pattern and its evaluation>
A composition for organic antireflection film (ARC-29; manufactured by Nissan Kagaku Co., Ltd.) is applied to a silicon wafer and baked at 205° C. for 60 seconds to give an organic reflection film having a film thickness of 78 nm on the wafer. The prevention film was formed. Then, the above resist composition was applied (spin-coated) on the organic antireflection film so that the film thickness after drying was 160 nm. After coating, the silicon wafer was prebaked on the direct hot plate at the temperature described in the "PB" column of Table 2 for 60 seconds to form a composition layer. A contact hole pattern (hole pitch: 120 nm) was formed on a silicon wafer on which a composition layer was formed, using an ArF excimer stepper for immersion exposure (XT: 1900 Gi; ASML, NA=1.35, 3/4 Annular XY polarized light). /Hole diameter 55 nm) was used, and the exposure amount was changed stepwise to perform exposure. Ultrapure water was used as the immersion medium.
After the exposure, post-exposure bake was performed on the hot plate at the temperature described in the column "PEB" of Table 2 for 60 seconds. Then, the composition layer on the silicon wafer was subjected to puddle development at 23° C. for 60 seconds using a 2.38% tetramethylammonium hydroxide aqueous solution as a developing solution to produce a resist pattern.

In the resist pattern obtained after development, the exposure amount at which the hole diameter formed using the mask was 55 nm was defined as the effective sensitivity.

<Evaluation of mask error factor (MEF)>
A resist pattern was formed using a mask having a mask hole diameter (hole diameter of a transparent portion of the mask) of 57 nm, 56 nm, 55 nm, 54 nm, and 53 nm (hole pitch is 120 nm in all) in terms of effective sensitivity. The mask hole diameter was plotted on the horizontal axis, and the hole diameter of the resist pattern formed (transferred) on the substrate by exposure was plotted on the vertical axis, and the slope of the regression line was calculated as the MEF value. The results are shown in Table 3. Numerical values in parentheses indicate MEF values.

The resist composition containing the salt of the present invention can produce a resist pattern with a good mask error factor (MEF), and is therefore suitable for fine processing of semiconductors.

Claims (10)

A salt represented by the formula (I).
[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
z represents an integer of 0 to 6, and when z is 2 or more, a plurality of R ¹ and R ² may be the same or different.
X ¹ is, * - CO-O -, * - O-CO -, * - O-CO-O- or * -O- (where * ^{is, C (R 1) (R} 2) or C (Q ¹ ) represents a bonding position with (Q ² ).
L ¹ represents a single bond or a saturated hydrocarbon group having 1 to 28 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group is —O—, —S—, —SO ₂ — or —CO—. May be replaced with.
A ¹ represents a divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and —CH ₂ — contained in the alicyclic hydrocarbon group is —O—, -S -, - SO ₂ - or -CO- may be replaced with.
R ^a represents an alicyclic hydrocarbon group which may having from 3 to 18 carbon atoms which may have a substituent, -CH ₂ contained in the alicyclic hydrocarbon group - is -O -, - S- , -SO ₂ - may be replaced or -CO-. However, at least one of —CH ₂ — contained in the alicyclic hydrocarbon group is replaced with —O— or —CO—.
Z ⁺ represents an organic cation. ] X ¹ is *-CO-O- or *-O-CO-O- (however, * represents a bonding position with C(R ¹ )(R ² ) or C(Q ¹ )(Q ² ). .) The salt according to claim 1. L ¹ is a single bond, an alkanediyl group (however, —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—), or an alkanediyl group and an alicyclic saturated group. Group formed by combining with a hydrocarbon group (however, —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—, and included in the alicyclic saturated hydrocarbon group. -CH ₂ - is, -O -, - S -, - SO 2 -. of or -CO- may be replaced with) salt according to claim 1 or 2 wherein the. -CH 2 R ^a is contained in the alicyclic hydrocarbon group (alicyclic hydrocarbon group which may having from 3 to 18 carbon atoms which may have a hydroxy group or a fluorine atom _- is, -O -, - S -, - SO ₂ - or -CO- may be substituted with the proviso, -CH ₂ contained in the alicyclic hydrocarbon group -. At least one is replaced by -O- or -CO- .) The salt according to any one of claims 1 to 3. An acid generator containing the salt according to claim 1. A resist composition containing the acid generator according to claim 5 and a resin containing a structural unit having an acid labile group. The structural unit having an acid labile group includes at least one selected from the group consisting of a structural unit represented by the formula (a1-1) and a structural unit represented by the formula (a1-2). Resist composition.
[In Formula (a1-1) and Formula (a1-2),
L ^a1 and L ^a2 each independently represent -O- or *-O-(CH ₂ ) _k1- CO-O-, k1 represents an integer of 1 to 7, and * represents -CO-. Represents a bond with.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these.
m1 represents any integer of 0-14.
n1 represents any integer of 0-10.
n1′ represents an integer of 0 to 3. ] The resist composition according to claim 6, further comprising a salt that generates an acid having a weaker acidity than the acid generated from the acid generator. The resist composition according to claim 6, further comprising a resin containing a structural unit having a fluorine atom. (1) A step of applying the resist composition according to any one of claims 6 to 9 onto a substrate,
(2) a step of drying the composition after coating 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,
A method for manufacturing a resist pattern including:.