Salt, acid generator, resist composition and method for producing resist pattern

Abstract

To provide a salt from which a resist pattern having good CD uniformity (CDU) can be produced.SOLUTION: The salt is a specific sulfonium compound represented by, for example, formula (1-1) below.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a salt for an acid generator used in semiconductor microfabrication, an acid generator containing the salt, a resist composition, and a method for producing a resist pattern. [Background technology]

[0002] Patent Document 1 describes a salt represented by the following formula and a resist composition containing the salt as an acid generator. TIFF0007763576000001.tif2874 [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 135003 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a salt that forms a resist pattern with better CD uniformity (CDU) than a resist pattern formed with the above resist composition. [Means for solving the problem]

[0005] The present invention includes the following inventions. [1] A salt represented by formula (I). TIFF0007763576000002.tif9491 [In formula (I), R 1 , R 2 and R 3 each independently represents an iodine atom or a fluorine atom. R 4 , R 5 , R 6 , R 7 , R 8 and R 9each independently represents a halogen atom, a hydroxy group, a haloalkyl group having 1 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms, and —CH2— contained in the haloalkyl group and the alkyl group may be replaced by —O— or —CO—. X 1 , X 2 and X 3 each independently represents an oxygen atom or a sulfur atom. m1 represents an integer of 1 to 5, and when m1 is 2 or greater, the groups in the parentheses may be the same or different. m2 represents an integer of 0 to 5, and when m2 is 2 or greater, the groups in the parentheses may be the same or different. m3 represents an integer of 0 to 5, and when m3 is 2 or greater, the groups in the parentheses may be the same or different. m4 represents an integer of 0 to 4, and when m4 is 2 or more, a plurality of R 4 may be the same or different from each other. m5 represents an integer of 0 to 4, and when m5 is 2 or more, a plurality of R 5 may be the same or different from each other. m6 represents an integer of 0 to 4, and when m6 is 2 or more, a plurality of R 6 may be the same or different from each other. m7 represents an integer of 0 to 4, and when m7 is 2 or more, a plurality of R 7 may be the same or different from each other. m8 represents an integer of 0 to 5, and when m8 is 2 or more, a plurality of R 8 may be the same or different from each other. m9 represents an integer of 0 to 5, and when m9 is 2 or more, a plurality of R 9 may be the same or different from each other. However, 1≦m1+m7≦5, 0≦m2+m8≦5, and 0≦m3+m9≦5. AI - represents an organic anion. [2]X 1 , X 2and X 3 [1] The salt according to [1], wherein [3] AI - is a sulfonate anion, a sulfonylimide anion, a sulfonylmethide anion, or a carboxylate anion. [4] AI - The salt according to any one of [1] to [3], wherein is a sulfonate anion, and the sulfonate anion is an anion represented by formula (IA). TIFF0007763576000003.tif2352[In formula (IA), Q 1 and Q 2 each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. L 1 represents a saturated hydrocarbon group having 1 to 24 carbon atoms, wherein -CH2- contained in the saturated hydrocarbon group may be replaced by -O- or -CO-, and wherein a hydrogen atom contained in the saturated hydrocarbon group may be substituted by a fluorine atom or a hydroxy group. Y 1 represents an optionally substituted methyl group or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and -CH2- contained in the alicyclic hydrocarbon group may be replaced by -O-, -SO2- or -CO-.] [5] An acid generator containing the salt according to any one of [1] to [4]. [6] A resist composition comprising the acid generator according to [5] and a resin having an acid labile group. [7] The resist composition according to [6], wherein the structural unit having an acid labile group comprises at least two of a structural unit represented by formula (a1-1) and a structural unit represented by formula (a1-2). TIFF0007763576000004.tif3985 [In formula (a1-1) and formula (a1-2), L a1 and L a2 are each independently -O- or -O-(CH2) k1 represents —CO—O—, k1 represents an integer of 1 to 7, and * represents the bonding position with —CO—. Ra4 and R a5 each independently represents a hydrogen atom or a methyl group. R a6 and R a7 each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining these. m1 represents an integer of 0 to 14. n1 represents an integer of 0 to 10. n1' represents an integer of 0 to 3. [8] The resist composition according to [6] or [7], further comprising a salt that generates an acid that is weaker in acidity than the acid generated from the acid generator. [9] (1) A step of applying the resist composition according to any one of [6] to [8] onto a substrate; (2) drying the applied composition to form a composition layer; (3) exposing the composition layer to light; (4) heating the composition layer after exposure; and (5) A method for producing a resist pattern, comprising the step of developing the composition layer after heating. [Effects of the Invention]

[0006] By using a resist composition that uses the salt of the present invention, a resist pattern with good CD uniformity (CDU) can be produced. DETAILED DESCRIPTION OF THE INVENTION

[0007] In this specification, the term "(meth)acrylic monomer" refers to at least one monomer selected from the group consisting of a monomer having a "CH=CH-CO-" structure and a monomer having a "CH=C(CH)-CO-" structure. Similarly, "(meth)acrylate" and "(meth)acrylic acid" refer to "at least one monomer selected from the group consisting of acrylates and methacrylates" and "at least one monomer selected from the group consisting of acrylic acid and methacrylic acid," respectively. When a structural unit having "CH=C(CH)-CO-" or "CH=CH-CO-" is exemplified, structural units having both groups are also exemplified. Furthermore, among the groups described herein, those that can have both a linear structure and a branched structure may be either. The term "combined group" refers to a group formed by combining two or more of the exemplified groups with their valences appropriately changed. When stereoisomers exist, all stereoisomers are included. In this specification, the term "solid content of the resist composition" refers to the sum of all components in the resist composition excluding the solvent (E), which will be described later.

[0008] <Salt represented by formula (I)> The present invention relates to a salt represented by formula (I) (hereinafter sometimes referred to as "salt (I)"). In the salt (I), the negatively charged side is sometimes called the "anion (I)" and the positively charged side is sometimes called the "cation (I)". R 4 , R 5 , R 6 , R 7 , R 8 and R 9 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R 4 , R 5 , R 6 , R 7 , R 8 and R 9The haloalkyl group having 1 to 12 carbon atoms in the formula (I) represents an alkyl group having 1 to 12 carbon atoms and a halogen atom, and examples thereof include a chloromethyl group, a bromomethyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a perfluorobutyl group, etc. The haloalkyl group preferably has 1 to 9 carbon atoms, and more preferably has 1 to 4 carbon atoms. R 4 , R 5 , R 6 , R 7 , R 8 and R 9 Examples of the alkyl group having 1 to 12 carbon atoms include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, octyl group, nonyl group, etc. The number of carbon atoms in the alkyl group is preferably 1 to 9, and more preferably 1 to 4. R 4 , R 5 , R 6 , R 7 , R 8 and R 9 When -CH2- contained in the haloalkyl group or alkyl group represented by the formula (I) is replaced with -O- or -CO-, the number of carbon atoms before the replacement is the total number of carbon atoms in the haloalkyl group or alkyl group. 4 , R 5 , R 6 , R 7 , R 8 and R 9may have a hydroxy group (a group in which -CH2- in a methyl group is replaced with -O-), a carboxyl group (a group in which -CH2-CH2- in an ethyl group is replaced with -O-CO-), an alkoxy group having 1 to 11 carbon atoms (a group in which -CH2- in an alkyl group having 2 to 12 carbon atoms is replaced with -O-), an alkoxycarbonyl group having 2 to 11 carbon atoms (a group in which -CH2-CH2- in an alkyl group having 3 to 12 carbon atoms is replaced with -O-CO-), an alkylcarbonyl group having 2 to 12 carbon atoms (a group in which -CH2- in an alkyl group having 2 to 12 carbon atoms is replaced with -CO-), or an alkylcarbonyloxy group having 2 to 11 carbon atoms (a group in which -CH2-CH2- in an alkyl group having 3 to 12 carbon atoms is replaced with -CO-O-). Examples of the alkoxy group having 1 to 11 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a 2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, and an undecyloxy group. The alkoxycarbonyl group having 2 to 11 carbon atoms, the alkylcarbonyl group having 2 to 12 carbon atoms, and the alkylcarbonyloxy group having 2 to 11 carbon atoms represent groups in which a carbonyl group or a carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group. Examples of the alkoxycarbonyl group having 2 to 11 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, and a butoxycarbonyl group. Examples of the alkylcarbonyl group having 2 to 12 carbon atoms include an acetyl group, a propionyl group, and a butyryl group. Examples of the alkylcarbonyloxy group having 2 to 11 carbon atoms include an acetyloxy group, a propionyloxy group, and a butyryloxy group. X 1 is preferably an oxygen atom. X 2 is preferably an oxygen atom. X 3 is preferably an oxygen atom. Preferably, m1 is 1 or 2. m2 is preferably 0 or 1. m3 is preferably 0 or 1. Preferably, m4 is 0, 1, 2 or 4. m5 is preferably 0 or 1. m6 is preferably 0 or 1. m7 is preferably 0, 1 or 2, and more preferably 0 or 1. Preferably, m8 is 0 or 1. m9 is preferably 0 or 1. 4 , R 5 and R 6 are each independently preferably an iodine atom, a fluorine atom, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, a haloalkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, more preferably an iodine atom, a fluorine atom, a hydroxy group, or an alkoxy group having 1 to 3 carbon atoms, and even more preferably an iodine atom, a fluorine atom, or a hydroxy group. 7 , R 8 and R 9 are each independently preferably an iodine atom, a fluorine atom, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, a haloalkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and more preferably an iodine atom, a fluorine atom, or an alkoxy group having 1 to 3 carbon atoms.

[0009] Examples of the cation (I) include the following cations: TIFF0007763576000005.tif188140

[0010] TIFF0007763576000006.tif185157

[0011] AI - Examples of the organic anion represented by the formula AI include a sulfonate anion, a sulfonylimide anion, a sulfonylmethide anion, and a carboxylate anion. - The organic anions represented by the formula (IA) are each independently preferably a sulfonate anion, and more preferably each independently an anion represented by the formula (IA). TIFF0007763576000007.tif2965[In formula (IA), Q 1 and Q 2 each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. L 1 represents a saturated hydrocarbon group having 1 to 24 carbon atoms, wherein -CH2- contained in the saturated hydrocarbon group may be replaced by -O- or -CO-, and wherein a hydrogen atom contained in the saturated hydrocarbon group may be substituted by a fluorine atom or a hydroxy group. Y 1 represents an optionally substituted methyl group or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and -CH2- contained in the alicyclic hydrocarbon group may be replaced by -O-, -SO2- or -CO-.]

[0012] In the anion represented by formula (IA), when -CH2- in the saturated hydrocarbon group is replaced with -O- or -CO-, the number of carbon atoms before the replacement is defined as the number of carbon atoms in the saturated hydrocarbon group. Also, when -CH2- in the alicyclic hydrocarbon group is replaced with -O-, -SO2-, or -CO-, the number of carbon atoms before the replacement is defined as the number of carbon atoms in the alicyclic hydrocarbon group.

[0013] Q 1 and Q 2 Examples of the perfluoroalkyl group having 1 to 6 carbon atoms include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluorohexyl group. Q 1 and Q 2 and are each independently preferably a fluorine atom or a trifluoromethyl group, and more preferably both are fluorine atoms.

[0014] L 1Examples of the divalent saturated hydrocarbon group in include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and may also be a group formed by combining two or more of these groups. Specific examples include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, a dodecane-1,12-diyl group, a tridecane-1,13-diyl group, a tetradecane-1,14-diyl group, a pentadecane-1,15-diyl group, a hexadecane-1,16-diyl group, and a heptadecane-1,17-diyl group; branched alkanediyl groups such as ethane-1,1-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-2,2-diyl, pentane-2,4-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl, pentane-1,4-diyl, and 2-methylbutane-1,4-diyl; monocyclic divalent alicyclic saturated hydrocarbon groups such as cycloalkanediyl groups, such as cyclobutane-1,3-diyl, cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, and cyclooctane-1,5-diyl; Examples include polycyclic divalent alicyclic saturated hydrocarbon groups such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, and adamantane-2,6-diyl group.

[0015] L 1 Examples of the group in which -CH2- in the divalent saturated hydrocarbon group represented by the formula (b1-1) is replaced with -O- or -CO- include groups represented by any of formulas (b1-1) to (b1-3). In the groups represented by formulas (b1-1) to (b1-3) and specific examples thereof, groups represented by formulas (b1-4) to (b1-11), * and ** represent bonding positions, * indicates -Y 1 represents the bonding position with

[0016] TIFF0007763576000008.tif26117[In formula (b1-1), L b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom. L b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and -CH2- contained in the saturated hydrocarbon group may be substituted with -O- or -CO-. However, L b2 and L b3 The total number of carbon atoms is 22 or less. In formula (b1-2), L b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom. L b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and -CH2- contained in the saturated hydrocarbon group may be substituted with -O- or -CO-. However, L b4 and L b5 The total number of carbon atoms is 22 or less. In formula (b1-3), L b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. L b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and -CH2- contained in the saturated hydrocarbon group may be substituted with -O- or -CO-. However, L b6 and L b7The total number of carbon atoms is 23 or less.

[0017] In the groups represented by formulae (b1-1) to (b1-3), when -CH2- contained in the saturated hydrocarbon group is replaced with -O- or -CO-, the number of carbon atoms before replacement is defined as the number of carbon atoms of the saturated hydrocarbon group. As the divalent saturated hydrocarbon group, L b1 Examples of the divalent saturated hydrocarbon group include the same as the divalent saturated hydrocarbon group. 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 a 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 a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom. L b7 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and -CH2- contained in the divalent saturated hydrocarbon group may be substituted with -O- or -CO-. L 1 As the divalent saturated hydrocarbon group represented by the formula (b1-1) or (b1-3), in which one --CH.sub.2-- contained in the group is replaced by --O-- or --CO--, a group represented by the formula (b1-1) or (b1-3) is preferred.

[0018] Examples of formula (b1-1) include groups represented by formulas (b1-4) to (b1-8). TIFF0007763576000009.tif48120[In formula (b1-4), L b8represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. In formula (b1-5), L b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and -CH2- 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 a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. However, L b9 and L b10 The total number of carbon atoms is 20 or less. In formula (b1-6), L b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms. L b12 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. However, L b11 and L b12 The total number of carbon atoms 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 -CH2- contained in the divalent saturated hydrocarbon group may be replaced with -O- or -CO-. L b15 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. However, L b13 ~L b15 The total number of carbon atoms is 19 or less. In formula (b1-8), L b16represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and -CH2- 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 a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. However, L b16 ~L b18 The total number of carbon atoms is 19 or less.

[0019] 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 b18is 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.

[0020] Examples of the group represented by formula (b1-3) include groups represented by formulas (b1-9) to (b1-11). TIFF0007763576000010.tif23139 formula (b1-9), L b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom. L b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group, or an alkylcarbonyloxy group. -CH2- contained in the alkylcarbonyloxy group may be replaced with -O- or -CO-, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group. However, L b19 and L b20 The total number of carbon atoms is 23 or less. In formula (b1-10), L b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom. L b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms. L b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group, or an alkylcarbonyloxy group. -CH2- contained in the alkylcarbonyloxy group may be replaced with -O- or -CO-, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group. However, L b21 , L b22 and Lb23 The total number of carbon atoms is 21 or less. In formula (b1-11), L b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom. L b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms. L b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group, or an alkylcarbonyloxy group. -CH2- contained in the alkylcarbonyloxy group may be replaced with -O- or -CO-, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group. However, L b24 , L b25 and L b26 The total number of carbon atoms is 21 or less.

[0021] In the groups represented by formulae (b1-9) to (b1-11), when a hydrogen atom contained in a saturated hydrocarbon group is substituted with an alkylcarbonyloxy group, the number of carbon atoms before substitution is defined as the number of carbon atoms in the saturated hydrocarbon group.

[0022] Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, a cyclohexylcarbonyloxy group, and an adamantylcarbonyloxy group.

[0023] Examples of the group represented by formula (b1-4) include the following. TIFF0007763576000011.tif16154

[0024] Examples of the group represented by formula (b1-5) include the following. TIFF0007763576000012.tif69148

[0025] Examples of the group represented by formula (b1-6) include the following. TIFF0007763576000013.tif44148

[0026] Examples of the group represented by formula (b1-7) include the following. TIFF0007763576000014.tif63153

[0027] Examples of the group represented by formula (b1-8) include the following. TIFF0007763576000015.tif23150

[0028] Examples of the group represented by formula (b1-2) include the following. TIFF0007763576000016.tif31161

[0029] Examples of the group represented by formula (b1-9) include the following. TIFF0007763576000017.tif44137

[0030] Examples of the group represented by formula (b1-10) include the following. TIFF0007763576000018.tif92165

[0031] Examples of the group represented by formula (b1-11) include the following. TIFF0007763576000019.tif85164

[0032] Y 1 Examples of the alicyclic hydrocarbon group represented by the formula include groups represented by formula (Y1) to formula (Y11) and formula (Y36) to formula (Y38). Y 1 When -CH2- contained in the alicyclic hydrocarbon group represented by the formula (Y12) is replaced by -O-, -S(O)2- or -CO-, the number of such groups may be one or more. Examples of such groups include groups represented by formula (Y12) to formula (Y35) and formula (Y39) to formula (Y41). * represents L1 represents the bonding position with

[0033] TIFF0007763576000020.tif75146Y 1 The alicyclic hydrocarbon group represented by the formula (Y1) is preferably a group represented by any one of formulas (Y1) to (Y20), formula (Y26), formula (Y27), formula (Y30), formula (Y31), formula (Y39) to formula (Y41), more preferably a group represented by formula (Y11), formula (Y15), formula (Y16), formula (Y20), formula (Y26), formula (Y27), formula (Y30), formula (Y31), formula (Y39) or formula (Y40), and even more preferably a group represented by formula (Y11), formula (Y15), formula (Y20), formula (Y26), formula (Y27), formula (Y30), formula (Y31), formula (Y39) or formula (Y40). Y 1 is a spiro ring containing an oxygen atom, such as those of formulae (Y28) to (Y35) and (Y39) to (Y40), the alkanediyl group between the two oxygen atoms preferably has one or more fluorine atoms. Furthermore, among the alkanediyl groups contained in the ketal structure, it is preferred that the methylene group adjacent to the oxygen atom is not substituted with a fluorine atom.

[0034] Y 1 The substituent of the methyl group represented by the formula (I) is 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, -(CH2) ja -CO-OR b1 group or -(CH2) ja -O-CO-R b1 group (in the formula, R b1 represents an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof. ja represents an integer of 0 to 4. -CH2- contained in the alkyl group having 1 to 16 carbon atoms and the alicyclic hydrocarbon group having 3 to 16 carbon atoms may be replaced by -O-, -S(O)2-, or -CO-. Y 1Examples of the substituent of the alicyclic hydrocarbon group represented by the formula (I) include 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 hydrocarbon group having 3 to 16 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, a glycidyloxy group, -(CH2) ja -CO-OR b1 group or -(CH2) ja -O-CO-R b1 group (in the formula, R b1 represents an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof. ja represents an integer of 0 to 4. -CH2- contained in the alkyl group having 1 to 16 carbon atoms and the alicyclic hydrocarbon group having 3 to 16 carbon atoms may be replaced by -O-, -S(O)2-, or -CO-.

[0035] 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 aromatic hydrocarbon groups include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, and a phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group. Examples of aromatic hydrocarbon groups having a chain hydrocarbon group include a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a p-ethylphenyl group, a p-tert-butylphenyl group, a 2,6-diethylphenyl group, and a 2-methyl-6-ethylphenyl group. Examples of aromatic hydrocarbon groups having an alicyclic hydrocarbon group include a p-cyclohexylphenyl group and a 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, a nonyl group, a decyl group, an undecyl group, and a dodecyl group. Examples of the alkyl group substituted with a hydroxy group include hydroxyalkyl groups such as a hydroxymethyl group and a hydroxyethyl group. Examples of the 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.

[0036] Y 1 Examples include the following: TIFF0007763576000021.tif140163

[0037] Y 1 is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, more preferably an alicyclic hydrocarbon group substituted with a hydroxy group, and even more preferably an adamantyl group which may have a substituent, and -CH2- constituting the alicyclic hydrocarbon group or the adamantyl group may be replaced with -CO-, -S(O)2- or -CO-. 1 is more preferably an adamantyl group, a hydroxyadamantyl group, an oxoadamantyl group, or a group represented by the following formula: and particularly preferably a hydroxyadamantyl group, an oxoadamantyl group, or a group containing these. TIFF0007763576000022.tif89156

[0038] The anion represented by formula (IA) is preferably an anion represented by formula (IA-1) to formula (IA-55) (hereinafter, sometimes referred to as "anion (IA-1)" or the like depending on the formula number), and more preferably an anion represented by any of formulas (IA-1) to (IA-4), (IA-9), (IA-10), (IA-24) to (IA-33), (IA-36) to (IA-40), and (IA-47) to (IA-55).

[0039] TIFF0007763576000023.tif100142

[0040] TIFF0007763576000024.tif95156

[0041] TIFF0007763576000025.tif142151

[0042] TIFF0007763576000026.tif106141

[0043] TIFF0007763576000027.tif113161

[0044] where R i2 ~R i7 are each independently, for example, an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group. i8 is, for example, a chain hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or a group formed by combining these, more preferably a methyl group, an ethyl group, a cyclohexyl group, or an adamantyl group. A41 Q is a single bond or an alkanediyl group having 1 to 4 carbon atoms. 1 and Q 2 has the same meaning as above. Specific examples of the anion represented by formula (IA) include the anions described in JP-A-2010-204646.

[0045] Preferable examples of the anion represented by formula (IA) include anions represented by formulas (Ia-1) to (Ia-34). TIFF0007763576000028.tif189154

[0046] TIFF0007763576000029.tif34138

[0047] TIFF0007763576000030.tif159166

[0048] Among these, anions represented by any one of formulae (Ia-1) to (Ia-3), (Ia-7) to (Ia-19), and (Ia-22) to (Ia-34) are preferred.

[0049] AI - Examples of the sulfonylimide anion represented by the formula (I) include the following. TIFF0007763576000031.tif40135

[0050] AI - Examples of the sulfonylmethide anion represented by the formula (I) include the following. TIFF0007763576000032.tif31128

[0051] AI - Examples of the carboxylic acid anion represented by the formula (I) include the following. TIFF0007763576000033.tif44154

[0052] Specific examples of the salt (I) include salts formed by any combination of the above-mentioned cations and anions. Specific examples of the salt (I) are shown in the table below. In the table below, each symbol represents the symbol attached to the structure representing the above-mentioned anion or cation. For example, salt (I-1) is a salt consisting of an anion represented by formula (Ia-1) and a cation represented by formula (Ic-1), and is the salt shown below. TIFF0007763576000034.tif31117

Table 1

[0053] Among them, salt (I) is salt (I-1) to salt (I-5), salt (I-13) to salt (I-25), salt (I-30) to salt (I-34), salt (I-42) to salt (I-54), salt (I-59) to salt (I-63), salt (I-71) to salt (I-83), salt (I-88) to salt (I-92), salt (I-100) to salt (I-112), salt (I-117) to salt (I-121), salt (I-129) ) ~ Salt (I-141), Salt (I-146) ~ Salt (I-150), Salt (I-158) ~ Salt (I-170), Salt (I-175) ~ Salt (I-179), Salt (I-187) ~ Salt (I-199), Salt (I-204) ~ Salt (I-208), Salt (I-216) ~ Salt (I-228), Salt (I-233) ~ Salt (I-237), Salt (I-245) ~ Salt (I-257), Salt (I-262) ~Salt (I-266), Salt (I-274) ~ Salt (I-286), Salt (I-291) ~ Salt (I-295), Salt (I-303) ~ Salt (I-315), Salt (I-320) ~ Salt (I-324), Salt (I-332) ~ Salt (I-344), Salt (I-349) ~ Salt (I-353), Salt (I-361) ~ Salt (I-373), Salt (I-378) ~ Salt (I-382), Salt (I-390) ~ Salt (I-402), salt (I-407) to salt (I-411), salt (I-419) to salt (I-431), salt (I-436) to salt (I-440), salt (I-448) to salt (I-460), salt (I-465) to salt (I-469), salt (I-477) to salt (I-489), salt (I-494) to salt (I-498), and salt (I-506) to salt (I-518) are preferred.

[0054] <Method for producing salt (I)> The salt (I) can be produced by reacting a salt represented by formula (Ia) with a salt represented by formula (Ib) in a solvent. TIFF0007763576000048.tif99162 [wherein all symbols have the same meanings as above. A , R B and R Ceach independently represents a hydrocarbon group having 1 to 12 carbon atoms, or R A , R B and R C may combine to form an aromatic ring. D represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.] Examples of the solvent include chloroform, monochlorobenzene, acetonitrile, and water. The reaction temperature is usually 15° C. to 80° C., and the reaction time is usually 0.5 to 24 hours.

[0055] Examples of the salt represented by formula (Ib) include salts represented by the following formula: These salts can be easily produced by a method similar to that described in JP 2011-116747 A or by known production methods. TIFF0007763576000049.tif92125

[0056] The salt represented by formula (Ia) can be produced by reacting the salt represented by formula (Ic), a compound represented by formula (I-d1), a compound represented by formula (I-d2), and a compound represented by formula (I-d3) in a solvent in the presence of potassium carbonate. TIFF0007763576000050.tif85148 [wherein all symbols have the same meanings as defined above.] Examples of the solvent include chloroform, monochlorobenzene, acetonitrile, and water. The reaction temperature is usually 15° C. to 100° C., and the reaction time is usually 0.5 to 24 hours.

[0057] Examples of the salt represented by formula (Ic) include salts represented by the following formula, which are readily available on the market. TIFF0007763576000051.tif36105

[0058] Examples of the compounds represented by formula (I-d1), (I-d2), and (I-d3) include the compounds represented by the following formulae, which are readily available on the market. TIFF0007763576000052.tif19146

[0059] The salt represented by formula (Ia) can be produced by reacting the salt represented by formula (Ie), a compound represented by formula (I-f1), a compound represented by formula (I-f2), and a compound represented by formula (I-f3) in a solvent in the presence of a base. TIFF0007763576000053.tif86151 [wherein all symbols have the same meanings as defined above.] Examples of the base include potassium hydroxide and sodium hydride. Examples of the solvent include chloroform, monochlorobenzene, acetonitrile, and water. The reaction temperature is usually 15° C. to 100° C., and the reaction time is usually 0.5 to 24 hours.

[0060] Examples of the salt represented by formula (Ie) include salts represented by the following formula, which are readily available on the market. JPEG0007763576000054.jpg35105

[0061] Examples of the compound represented by formula (I-f1), the compound represented by formula (I-f2), and the compound represented by formula (I-f3) include the compounds represented below, which are easily available on the market. TIFF0007763576000055.tif2196

[0062] <Acid generator> The acid generator of the present invention contains a salt (I). It may contain one kind of salt (I) or two or more kinds of salts (I). 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.

[0063] The acid generator (B) may be either nonionic or ionic. Nonionic acid generators include sulfonate esters (e.g., 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), sulfones (e.g., disulfone, ketosulfone, sulfonyldiazomethane), etc. Ionic acid generators include onium salts containing onium cations (e.g., diazonium salts, phosphonium salts, sulfonium salts, iodonium salts). Anions of onium salts include sulfonate anions, sulfonylimide anions, sulfonylmethide anions, etc.

[0064] The acid generator (B) may be a compound that generates an acid when exposed to radiation, as described in JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, JP-A-62-153853, JP-A-63-146029, U.S. Pat. No. 3,779,778, U.S. Pat. No. 3,849,137, German Patent No. 3,914,407, or European Patent No. 126,712. Compounds produced by known methods may also be used. Two or more types of acid generator (B) may be used in combination.

[0065] The acid generator (B) is preferably a fluorine-containing acid generator, and more preferably a salt represented by formula (B1) (hereinafter sometimes referred to as "acid generator (B1)"). TIFF0007763576000056.tif2862[In formula (B1), Q b1 and Q b2 each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. L b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, in which -CH2- contained in the saturated hydrocarbon group may be replaced by -O- or -CO-, and in which a hydrogen atom contained in the saturated hydrocarbon group may be replaced by a fluorine atom or a hydroxy group. Y represents an optionally substituted methyl group or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and -CH2- contained in the alicyclic hydrocarbon group may be replaced by -O-, -S(O)2- or -CO-. Z1 + represents an organic cation.

[0066] Q in formula (B1) b1 , Q b2 , L b1 and Y are the same as Q in the above formula (IA), 1 , Q 2 , L 1 and Y 1 And similar things can be mentioned. Examples of the sulfonate anion in formula (B1) include the same anions as those represented by formula (IA).

[0067] Z1 + Examples of the organic cation 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 preferred, and arylsulfonium cations are more preferred. Specific examples include cations represented by any of formulas (b2-1) to (b2-4) (hereinafter, sometimes referred to as "cation (b2-1)" depending on the formula number).

[0068] TIFF0007763576000057.tif77115In equations (b2-1) to (b2-4), R b4 ~R b6each independently represent a chain hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, a hydrogen atom contained in the chain hydrocarbon group may be substituted with a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, or a glycidyloxy group, and a hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group, or an alkoxy group having 1 to 12 carbon atoms. R b4 and R b5 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached, and -CH2- contained in the ring may be replaced with -O-, -S- or -CO-. R b7 and R b8 each independently represents a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. m2 and n2 each independently represent an integer of 0 to 5; When m2 is 2 or more, multiple R b7 may be the same or different, and when n2 is 2 or more, multiple R b8 may be the same or different. R b9 and R b10 each independently represents 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 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached, and -CH2- contained in the ring may be replaced with -O-, -S- or -CO-. R b11 represents a hydrogen atom, a chain hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. R b12represents 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 a hydrogen atom contained in the chain hydrocarbon may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a hydrogen atom contained in the aromatic hydrocarbon group may be substituted with an alkoxy group having 1 to 12 carbon atoms or an alkylcarbonyloxy group having 1 to 12 carbon atoms. R b11 and R b12 and may be bonded to each other to form a ring including the -CH-CO- to which they are bonded, and -CH2- contained in the ring may be replaced by -O-, -S- or -CO-. R b13 ~R b18 each independently represents a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. L b31 represents a sulfur atom or an oxygen atom. o2, p2, s2, and t2 each independently represent an integer of 0 to 5. q2 and r2 each independently represent an integer of 0 to 4; u2 represents 0 or 1. When o2 is 2 or more, multiple R b13 are the same or different, and when p2 is 2 or more, multiple R b14 are the same or different, and when q2 is 2 or more, multiple R b15 are the same or different, and when r2 is 2 or more, multiple R b16 are the same or different, and when s2 is 2 or more, multiple R b17 are the same or different, and when t2 is 2 or more, multiple R b18 are the same or different.

[0069] The aliphatic hydrocarbon group refers to a chain hydrocarbon group and an alicyclic hydrocarbon group. Examples of the chain hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, and 2-ethylhexyl. In particular, R b9~R b12 The chain hydrocarbon group preferably has 1 to 12 carbon atoms. The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and cyclodecyl. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl, adamantyl, and norbornyl groups, as well as the following groups: TIFF0007763576000058.tif10159 In particular, R b9 ~R b12 The alicyclic hydrocarbon group preferably has 3 to 18 carbon atoms, and more preferably has 4 to 12 carbon atoms.

[0070] Examples of the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-methyladamantan-2-yl group, a 2-ethyladamantan-2-yl group, a 2-isopropyladamantan-2-yl group, a methylnorbornyl group, an isobornyl group, etc. In the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group, the total number of carbon atoms in the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.

[0071] Examples of aromatic hydrocarbon groups include aryl groups such as a phenyl group, a biphenyl group, a naphthyl group, and a phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and examples thereof include aromatic hydrocarbon groups having a chain hydrocarbon group (such as a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a p-ethylphenyl group, a p-tert-butylphenyl group, a 2,6-diethylphenyl group, and a 2-methyl-6-ethylphenyl group) and aromatic hydrocarbon groups having an alicyclic hydrocarbon group (such as a p-cyclohexylphenyl group and a p-adamantylphenyl group). 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 are preferred. Examples of aromatic hydrocarbon groups in which hydrogen atoms are substituted with alkoxy groups include p-methoxyphenyl groups. Examples of the chain hydrocarbon group in which a hydrogen atom is substituted with an aromatic hydrocarbon group include aralkyl groups such as a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, and a naphthylethyl group.

[0072] 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.

[0073] R b4 and R b5 and bond to each other together with the sulfur atom to which they are bonded to form a ring which may be monocyclic, polycyclic, aromatic, non-aromatic, saturated, or unsaturated. This ring may be a ring having 3 to 18 carbon atoms, preferably a ring having 4 to 18 carbon atoms. The ring containing a sulfur atom may be a 3- to 12-membered ring, preferably a 3- to 7-membered ring, such as the rings shown below. * represents a bonding position. TIFF0007763576000059.tif23144

[0074] R b9 and R b10The ring formed by these together may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. This ring may be a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Examples thereof include a thiolan-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring. R b11 and R b12 The ring formed by combining these may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. Examples of this ring include a 3- to 12-membered ring, and preferably a 3- to 7-membered ring. Examples include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

[0075] Among the cations (b2-1) to (b2-4), the cation (b2-1) is preferred. Examples of the cation (b2-1) include the following cations. TIFF0007763576000060.tif73149

[0076] TIFF0007763576000061.tif69136

[0077] Examples of the cation (b2-2) include the following cations. TIFF0007763576000062.tif16131

[0078] Examples of the cation (b2-3) include the following cations. TIFF0007763576000063.tif25122

[0079] Examples of the cation (b2-4) include the following cations. TIFF0007763576000064.tif108153

[0080] The acid generator (B) is a combination of the above-mentioned anions and the above-mentioned organic cations, which can be combined arbitrarily. Preferred examples of the acid generator (B) include a combination of an anion represented by any of formulas (Ia-1) to (Ia-3), (Ia-7) to (Ia-16), (Ia-18), (Ia-19), and (Ia-22) to (Ia-34) with a cation (b2-1) or a cation (b2-3).

[0081] Preferred examples of the acid generator (B) include those represented by formulas (B1-1) to (B1-48). Among these, those containing an arylsulfonium cation are preferred, and those represented by formulas (B1-1) to (B1-3), (B1-5) to (B1-7), (B1-11) to (B1-14), (B1-20) to (B1-26), (B1-29), and (B1-31) to (B1-48) are particularly preferred. TIFF0007763576000065.tif119149

[0082] JPEG0007763576000066.jpg77147

[0083] JPEG0007763576000067.jpg147147

[0084] JPEG0007763576000068.jpg60154

[0085] TIFF0007763576000069.tif60166

[0086] When the acid generator contains a salt (I) and an acid generator (B), the ratio of the salt (I) to the acid generator (B) (mass ratio; salt (I):acid generator (B)) is usually 1:99 to 99:1, preferably 2:98 to 98:2, more preferably 5:95 to 95:5, even more preferably 10:90 to 90:10, and particularly preferably 15:85 to 85:15. In the resist composition of the present invention, the total content of the acid generators is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 3 parts by mass or more and 35 parts by mass or less, and even more preferably 5 parts by mass or more and 35 parts by mass or less, relative to 100 parts by mass of the resin (A) described below.

[0087] <Resist composition> The resist composition of the present invention contains an acid generator containing a salt (I) and a resin having an acid labile group (hereinafter sometimes referred to as "resin (A)"). Here, the "acid labile group" refers to a group that has a leaving group and that is eliminated upon contact with an acid, converting the structural unit into a structural unit having a hydrophilic group (e.g., a hydroxy group or a carboxy group). The resist composition of the present invention preferably contains a quencher such as a salt that generates an acid with a weaker acidity than the acid generated from the acid generator (hereinafter may be referred to as "quencher (C)"), and preferably contains a solvent (hereinafter may be referred to as "solvent (E)").

[0088] <Resin (A)> Resin (A) has a structural unit having an acid labile group (hereinafter sometimes referred to as "structural unit (a1)"). Resin (A) preferably further contains a structural unit other than structural unit (a1). Examples of structural units other than structural unit (a1) include a structural unit not having an acid labile group (hereinafter sometimes referred to as "structural unit (s)"), structural units other than structural unit (a1) and structural unit (s) (for example, a structural unit having a halogen atom (hereinafter sometimes referred to as "structural unit (a4)") described below, a structural unit having a non-leaving hydrocarbon group (hereinafter sometimes referred to as "structural unit (a5)") described below, and other structural units derived from monomers known in the art.

[0089] <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 preferably a group represented by formula (1) (hereinafter also referred to as group (1)) and / or a group represented by formula (2) (hereinafter also referred to as group (2)). TIFF0007763576000070.tif1988[In formula (1), R a1 , R a2 and R a3 each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group combining these, or R a1 and R a2 are bonded to each other to form a non-aromatic hydrocarbon ring having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded. ma and na each independently represent 0 or 1, and at least one of ma and na represents 1. * indicates the bond position.] TIFF0007763576000071.tif2171[In formula (2), R a1’ and R a2’ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms; R a3’ represents a hydrocarbon group having 1 to 20 carbon atoms, or R a2’ and R a3’ are bonded to each other to form a heterocyclic ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded and X, and -CH2- contained in the hydrocarbon group and the heterocyclic ring may be replaced with -O- or -S-. X represents an oxygen atom or a sulfur atom. na' represents 0 or 1. * indicates the bond position.]

[0090] R a1 , R a2 and R a3 Examples of the alkyl group in 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. R a1 , R a2 and R a3The alicyclic hydrocarbon group in may be either monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Examples of polycyclic alicyclic hydrocarbon groups include decahydronaphthyl, adamantyl, and norbornyl groups, as well as the following groups (where * indicates a bonding position): a1 , R a2 and R a3 The alicyclic hydrocarbon group preferably has 3 to 16 carbon atoms. Examples of the group formed by combining an alkyl group with an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group, and a norbornylethyl group. Preferably, ma is 0 and na is 1. R a1 and R a2 -C(R a1 )(R a2 )(R a3 ) includes the following rings. The non-aromatic hydrocarbon ring preferably has 3 to 12 carbon atoms. * indicates the bonding position with -O-. TIFF0007763576000073.tif30139

[0091] R a1’ , R a2’ and R a3’ Examples of the hydrocarbon group in include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these groups. The alkyl group and the alicyclic hydrocarbon group are represented by R a1 , R a2 and R a3 Examples of the groups include the same as those listed in the above. Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, and a phenanthryl group. Examples of the combined group include a group combining the above-mentioned alkyl group and alicyclic hydrocarbon group (for example, a cycloalkylalkyl group), aralkyl groups such as a benzyl group, aromatic hydrocarbon groups having an alkyl group (e.g., a p-methylphenyl group, a p-tert-butylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a 2,6-diethylphenyl group, a 2-methyl-6-ethylphenyl group, etc.), aromatic hydrocarbon groups having an alicyclic hydrocarbon group (e.g., a p-cyclohexylphenyl group, a p-adamantylphenyl group), and aryl-cycloalkyl groups such as a phenylcyclohexyl group. R a2’ and R a3’ When they are bonded to each other to form a heterocycle together with the carbon atoms to which they are attached and X, -C(R a1’ )(R a3’ )-XR a2’ Examples of the ring include the following: * indicates the bonding position. TIFF0007763576000074.tif19130R a1’ and R a2’ At least one of these is preferably a hydrogen atom. na' is preferably 0.

[0092] Examples of the group (1) include the following groups. In formula (1), R a1 , R a2 and R a3 is an alkyl group, ma=0, and na=1. The group is preferably a tert-butoxycarbonyl group. In formula (1), R a1 , R a2 together with the carbon atom to which they are attached form an adamantyl group, and R a3 is an alkyl group, ma=0, and na=1. In formula (1), R a1 and R a2 are each independently an alkyl group, and R a3 is an adamantyl group, ma=0, and na=1. Specific examples of the group (1) include the following: * represents the bonding position. TIFF0007763576000075.tif73158

[0093] Specific examples of group (2) include the following groups: * represents the bonding position. TIFF0007763576000076.tif66153

[0094] The monomer (a1) is preferably a monomer having an acid labile group and an ethylenically unsaturated bond, more preferably a (meth)acrylic monomer having an acid labile group.

[0095] Of the (meth)acrylic monomers having an acid labile group, preferred are those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms. When a resin (A) having a structural unit derived from a monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used in a resist composition, the resolution of the resist pattern can be improved.

[0096] Examples of structural units derived from a (meth)acrylic monomer having group (1) include a structural unit represented by formula (a1-0) (hereinafter, sometimes referred to as structural unit (a1-0)), a structural unit represented by formula (a1-1) (hereinafter, sometimes referred to as structural unit (a1-1)), or a structural unit represented by formula (a1-2) (hereinafter, sometimes referred to as structural unit (a1-2)). Preferably, at least one structural unit selected from the group consisting of structural unit (a1-1) and structural unit (a1-2) is used. These may be used alone or in combination of two or more. TIFF0007763576000077.tif39127 [In formula (a1-0), formula (a1-1) and formula (a1-2), L a01 , L a1 and L a2 are each independently -O- or * -O-(CH2) k1 represents —CO—O—, k1 represents an integer of 1 to 7, and * represents the bonding position with —CO—. R a01 , R a4 and R a5 each independently represents a hydrogen atom or a methyl group. R a02 , R a03 and R a04 each independently represents 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 represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining these. m1 represents an integer of 0 to 14. n1 represents an integer of 0 to 10. n1' represents an integer of 0 to 3.

[0097] R a01 , R a4 and R a5 is preferably a methyl group. L a01 , L a1 and L a2 is preferably an oxygen atom or —O—(CH2) k01 It is —CO—O— (wherein k01 is preferably an integer of any one of 1 to 4, more preferably 1), and more preferably an oxygen atom. R a02 , R a03 , R a04 , R a6 and R a7 The alkyl group, alicyclic hydrocarbon group and combination thereof in the formula (1) include R a1 ~R a3 Examples of the groups include the same groups as those listed in the above. R a02 , R a03 , and R a04 The alkyl group in the formula (I) preferably has 1 to 6 carbon atoms, is more preferably a methyl group or an ethyl group, and is even more preferably a methyl group. R a6 and R a7The alkyl group in the formula (I) preferably has 1 to 6 carbon atoms, is more preferably a methyl group, an ethyl group, or an isopropyl group, and is even more preferably an ethyl group or an isopropyl group. R a02 , R a03 and R a04 The alicyclic hydrocarbon group preferably has 5 to 12 carbon atoms, and more preferably 5 to 10 carbon atoms. In the group in which an alkyl group and an alicyclic hydrocarbon group are combined, the total number of carbon atoms in the combination of the alkyl group and the alicyclic hydrocarbon group is preferably 18 or less. R a02 and R a03 is preferably an alkyl group having 1 to 6 carbon atoms, 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 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group or an isopropyl group, and even 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.

[0098] Examples of the structural unit (a1-0) include structural units represented by any one of formulas (a1-0-1) to (a1-0-12) and R a01 Examples of structural units include those in which a methyl group corresponding to the formula (a1-0-1) is replaced with a hydrogen atom, and structural units represented by any of formulas (a1-0-1) to (a1-0-10) are preferred. TIFF0007763576000078.tif65159

[0099] Examples of the structural unit (a1-1) include structural units derived from monomers described in JP-A-2010-204646. Among these, structural units represented by any one of formulas (a1-1-1) to (a1-1-4) and R in the structural unit (a1-1) are preferred. a4 A structural unit in which a methyl group corresponding to the formula (a1-1-1) is replaced with a hydrogen atom is preferred, and a structural unit represented by any one of formulas (a1-1-1) to (a1-1-4) is more preferred. TIFF0007763576000079.tif43119

[0100] The structural unit (a1-2) includes a structural unit represented by any one of formulas (a1-2-1) to (a1-2-6) and R a5 and structural units in which a methyl group corresponding to the formula (a1-2-2), (a1-2-5) and (a1-2-6) are preferred. TIFF0007763576000080.tif33156

[0101] When the resin (A) contains the structural unit (a1-0), the content thereof is usually 5 to 60 mol %, preferably 5 to 50 mol %, and more preferably 10 to 40 mol %, based on all structural units in the resin (A). When the resin (A) contains the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is usually 10 to 95 mol %, preferably 15 to 90 mol %, more preferably 20 to 85 mol %, even more preferably 25 to 80 mol %, and still more preferably 30 to 75 mol %, based on all structural units in the resin (A).

[0102] An example of the structural unit (a1) having the group (2) is a structural unit represented by formula (a1-4) (hereinafter, sometimes referred to as "structural unit (a1-4)"). TIFF0007763576000081.tif4071[In formula (a1-4), R a32represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. R a33 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy 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 represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms; R a36 represents a hydrocarbon group having 1 to 20 carbon atoms, or R a35 and R a36 are bonded to each other to form, together with the -CO- to which they are bonded, a divalent hydrocarbon group having 2 to 20 carbon atoms, and the hydrocarbon group and the -CH2- contained in the divalent hydrocarbon group may be replaced by -O- or -S-.]

[0103] R a32 and R a33 Examples of the alkyl group in include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, and a hexyl group. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group. R a32 and R a33 Examples of the halogen atom in the formula include a fluorine atom, a chlorine atom, and a bromine atom. Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a propyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a butyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, a hexyl group, and a perfluorohexyl group. 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. Of these, an alkoxy group having 1 to 4 carbon atoms is preferred, a methoxy group or an ethoxy group is more preferred, and a methoxy group is even more preferred. Alkylcarbonyl groups include acetyl, propionyl and butyryl groups. Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, and a butyryloxy group. R a34 , R a35 and R a36 Examples of the hydrocarbon group in include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group consisting of a combination thereof. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. The alicyclic hydrocarbon group may be either monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Examples of polycyclic alicyclic hydrocarbon groups include decahydronaphthyl, adamantyl, norbornyl, and the following groups (* indicates the bonding position): TIFF0007763576000082.tif10152 Examples of aromatic hydrocarbon groups include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, and a phenanthryl group. Examples of the combined group include a group combining the above-mentioned alkyl group and alicyclic hydrocarbon group (for example, a cycloalkylalkyl group), an aralkyl group such as a benzyl group, an aromatic hydrocarbon group having an alkyl group (such as a p-methylphenyl group, a p-tert-butylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a 2,6-diethylphenyl group, or a 2-methyl-6-ethylphenyl group), an aromatic hydrocarbon group having an alicyclic hydrocarbon group (such as a p-cyclohexylphenyl group or a p-adamantylphenyl group), and an aryl-cyclohexyl group such as a phenylcyclohexyl group. a36 Examples of the group include an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these.

[0104] In formula (a1-4), R a32 is preferably a hydrogen atom. R a33 As the alkyl group, an alkoxy group having 1 to 4 carbon atoms is preferred, a methoxy group and an ethoxy group are more preferred, and a methoxy group is even more preferred. la is preferably 0 or 1, and more preferably 0. R a34 is preferably a hydrogen atom. R a35 is preferably an alkyl group or an alicyclic hydrocarbon group having 1 to 12 carbon atoms, and more preferably a methyl group or an ethyl group. R a36 The hydrocarbon group in R is preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these, and more preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic aliphatic hydrocarbon group having 3 to 18 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms. a36 The alkyl group and alicyclic hydrocarbon group in R are preferably unsubstituted. a36 The aromatic hydrocarbon group in is preferably an aromatic ring having an aryloxy group having 6 to 10 carbon atoms.

[0105] -OC(R a34 )(R a35 )-OR a36 is eliminated on contact with an acid (e.g., p-toluenesulfonic acid) to form a hydroxy group.

[0106] Examples of the structural unit (a1-4) include structural units derived from monomers described in JP-A-2010-204646. Preferred are structural units represented by formulas (a1-4-1) to (a1-4-12) and R in the structural unit (a1-4). a32 and more preferably, the structural units represented by formula (a1-4-1) to formula (a1-4-5) and formula (a1-4-10), respectively. TIFF0007763576000083.tif68157

[0107] When the resin (A) contains the structural unit (a1-4), the content thereof is preferably 10 to 95 mol %, more preferably 15 to 90 mol %, even more preferably 20 to 85 mol %, even more preferably 20 to 70 mol %, and particularly preferably 20 to 60 mol %, based on the total of all structural units in the resin (A).

[0108] Examples of the structural unit derived from a (meth)acrylic monomer having the group (2) include a structural unit represented by formula (a1-5) (hereinafter, sometimes referred to as "structural unit (a1-5)"). TIFF0007763576000084.tif4558 formula (a1-5), R a8 represents an alkyl group having 1 to 6 carbon atoms which may have one or more halogen atoms, a hydrogen atom, or a halogen atom. Z a1 is a single bond or -(CH2) h3 -CO-L 54 -, h3 represents an integer of 1 to 4, * represents L 51 represents the bonding position with 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.

[0109] Examples of halogen atoms include fluorine atoms and chlorine atoms, with fluorine atoms being preferred. 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 a trifluoromethyl group. 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. L 52 and L 53 Among these, it is preferred that one is —O— and the other is —S—. s1 is preferably 1. s1' is preferably an integer of 0 to 2. Z a1 is preferably a single bond or —CH2—CO—O—.

[0110] Examples of the structural unit (a1-5) include structural units derived from monomers described in JP-A-2010-61117. Among these, the structural units represented by formulas (a1-5-1) to (a1-5-4) are preferred, and the structural unit represented by formula (a1-5-1) or (a1-5-2) is more preferred. TIFF0007763576000085.tif33133

[0111] When the resin (A) contains the structural unit (a1-5), the content thereof is preferably 1 to 50 mol %, more preferably 3 to 45 mol %, even more preferably 5 to 40 mol %, and even more preferably 5 to 30 mol %, based on the total structural units of the resin (A).

[0112] Further, examples of the structural unit (a1) include the following structural units. TIFF0007763576000086.tif31162

[0113] When the resin (A) contains structural units such as (a1-3-1) to (a1-3-7) above, the content thereof is preferably 10 to 95 mol %, more preferably 15 to 90 mol %, even more preferably 20 to 85 mol %, still more preferably 20 to 70 mol %, even more preferably 20 to 60 mol %, and particularly preferably 10 to 40 mol %, based on the total structural units of the resin (A).

[0114] <Structural unit(s)> The structural unit (s) is derived from a monomer (hereinafter sometimes referred to as "monomer (s)") that does not have an acid labile group. As the monomer from which the structural unit (s) is derived, 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. By using a resin having a structural unit that has a hydroxy group but no acid labile group (hereinafter sometimes referred to as "structural unit (a2)") and / or a structural unit that has a lactone ring but no acid labile group (hereinafter sometimes referred to as "structural unit (a3)") in the resist composition of the present invention, the resolution of the resist pattern and adhesion to the substrate can be improved.

[0115] <Structural unit (a2)> The hydroxy group contained in the structural unit (a2) may be an alcoholic hydroxy group or a phenolic hydroxy group. When producing a resist pattern from the resist composition of the present invention, if a high-energy ray such as a KrF excimer laser (248 nm), an electron beam, or EUV (extreme ultraviolet light) is used as an exposure light source, it is preferable to use a structural unit (a2) having a phenolic hydroxy group as the structural unit (a2). Furthermore, if an ArF excimer laser (193 nm) or the like is used, it is more preferable to use the structural unit (a2-1) or structural unit (a2-A) described below as the structural unit (a2). The structural unit (a2) may contain one type alone or two or more types.

[0116] In the structural unit (a2), the structural unit having a phenolic hydroxy group includes a structural unit represented by formula (a2-A) (hereinafter, sometimes referred to as "structural unit (a2-A)"). TIFF0007763576000087.tif4349[In formula (a2-A), R a50 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. R a51 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or a methacryloyloxy group. A a50 is a single bond or *-X a51 -(A a52 -X a52 ) nb - represents -R a50 represents the bond position with the carbon atom to which it is bonded. A a52 represents an alkanediyl group having 1 to 6 carbon atoms. X a51 and X a52 each independently represents -O-, -CO-O- or -O-CO-. nb represents 0 or 1. mb represents an integer of 0 to 4. When mb is an integer of 2 or more, a plurality of R a51may be the same or different.]

[0117] R a50 Examples of the halogen atom in the formula include a fluorine atom, a chlorine atom, and a bromine atom. R a50 Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom in the formula (I) include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a propyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a butyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, a hexyl group, and a perfluorohexyl group. R a50 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group. R a51 Examples of the alkyl group in 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. R a51 Examples of the alkoxy group in 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 preferred, a methoxy group or an ethoxy group is more preferred, and a methoxy group is even more preferred. R a51 Examples of the alkylcarbonyl group in the formula include an acetyl group, a propionyl group, and a butyryl group. R a51 The alkylcarbonyloxy group in the formula (I) includes an acetyloxy group, a propionyloxy group, and a butyryloxy group. R a51 is preferably a methyl group.

[0118] *-X a51 -(A a52 -X a52 ) nb -Examples include *-O-, *-CO-O-, *-O-CO-, *-CO-OA a52 -CO-O-, *-O-CO-A a52 -O-, *-OA a52 -CO-O-, *-CO-OA a52 -O-CO-, *-O-CO-A a52 -O-CO-, and *-CO-O- and *-CO-OA are particularly mentioned. a52 -CO-O- or *-OA a52 -CO-O- is preferred.

[0119] Examples of the alkanediyl group include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group. A a52 is preferably a methylene group or an ethylene group.

[0120] A a50 is a single bond, *-CO-O- or *-CO-OA a52 -CO-O- is preferred, a single bond, *-CO-O- or *-CO-O-CH2-CO-O- is more preferred, and a single bond or *-CO-O- is even more preferred.

[0121] mb is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0. The hydroxy group is preferably bonded to the o- or p-position of the benzene ring, more preferably to the p-position.

[0122] Examples of the structural unit (a2-A) include structural units derived from monomers described in JP-A Nos. 2010-204634 and 2012-12577.

[0123] The structural unit (a2-A) includes structural units represented by formulas (a2-2-1) to (a2-2-6) and R in the structural unit (a2-A) in the structural units represented by formulas (a2-2-1) to (a2-2-6). a50 The structural unit (a2-A) is a structural unit represented by formula (a2-2-1), a structural unit represented by formula (a2-2-3), a structural unit represented by formula (a2-2-6), and a structural unit represented by formula (a2-2-1), a structural unit represented by formula (a2-2-3), or a structural unit represented by formula (a2-2-6), in which R in the structural unit (a2-A) is substituted with a hydrogen atom. a50 It is preferable that the structural unit is a structural unit in which a methyl group corresponding to the following formula is substituted with a hydrogen atom: TIFF0007763576000088.tif42166

[0124] 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 %, more preferably 10 to 70 mol %, even more preferably 15 to 65 mol %, still more preferably 20 to 65 mol %, and even more preferably 20 to 50 mol %, based on all structural units. The structural unit (a2-A) can be incorporated into the resin (A) by, for example, polymerizing the structural unit (a1-4) and then treating with an acid such as p-toluenesulfonic acid. Alternatively, the structural unit (a2-A) can be incorporated into the resin (A) by polymerizing the structural unit (a1-4) and then treating with an alkali such as tetramethylammonium hydroxide.

[0125] An example of the structural unit (a2) having an alcoholic hydroxy group is a structural unit represented by formula (a2-1) (hereinafter, sometimes referred to as "structural unit (a2-1)"). TIFF0007763576000089.tif3954 formula (a2-1), L a3 is -O- or *-O-(CH2) k2 represents -CO-O-, k2 represents an integer of 1 to 7. * represents the bonding position with —CO—. R a14 represents a hydrogen atom or a methyl group. R a15 and R a16 each independently represents a hydrogen atom, a methyl group, or a hydroxy group. o1 represents an integer of 0 to 10.

[0126] In equation (a2-1), L a3 is preferably -O-, -O-(CH2) f1 It is —CO—O— (wherein f1 represents an integer of 1 to 4), and more preferably —O—. R a14 is preferably a methyl group. R a15 is preferably a hydrogen atom. R a16 is preferably a hydrogen atom or a hydroxy group. o1 is preferably an integer of 0 to 3, and more preferably 0 or 1.

[0127] Examples of the structural unit (a2-1) include structural units derived from monomers described in JP 2010-204646 A. A structural unit represented by any one of formulas (a2-1-1) to (a2-1-6) is preferred, a structural unit represented by any one of formulas (a2-1-1) to (a2-1-4) is more preferred, and a structural unit represented by formula (a2-1-1) or formula (a2-1-3) is even more preferred. TIFF0007763576000090.tif50138

[0128] When the resin (A) contains the structural unit (a2-1), the content thereof is usually 1 to 45 mol %, preferably 1 to 40 mol %, more preferably 1 to 35 mol %, even more preferably 2 to 20 mol %, and still more preferably 2 to 10 mol %, based on all structural units in the resin (A).

[0129] <Structural unit (a3)> The lactone ring contained in the structural unit (a3) ​​may be a monocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ring, or a δ-valerolactone ring, or a condensed ring of a monocyclic lactone ring with another ring. Preferred examples include a γ-butyrolactone ring, an adamantane lactone ring, or a bridged ring containing a γ-butyrolactone ring structure (for example, a structural unit represented by the following formula (a3-2)).

[0130] The structural unit (a3) ​​is preferably a structural unit represented by formula (a3-1), formula (a3-2), formula (a3-3), or formula (a3-4). One of these may be contained alone, or two or more may be contained. TIFF0007763576000091.tif46147 [In formula (a3-1), formula (a3-2), formula (a3-3) and formula (a3-4), L a4 , L a5 and L a6 are each independently -O- or -O-(CH2) k3 It represents a group represented by —CO—O— (k3 represents an integer of 1 to 7). L a7 -O-, *-OL a8 -O-, *-OL a8 -CO-O-, *-OL a8 -CO-OL a9 -CO-O- or *-OL a8 -O-CO-L a9 Represents -O-. L a8 and L a9 each independently represents an alkanediyl group having 1 to 6 carbon atoms. * indicates the bonding position with the carbonyl group. R a18, R a19 and R a20 each independently represents a hydrogen atom or a methyl group. R a24 represents an alkyl group having 1 to 6 carbon atoms which may have one or more halogen atoms, a hydrogen atom, or a halogen atom. X a3 represents -CH2- 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 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. p1 represents an integer of 0 to 5. q1 represents an integer of 0 to 3. r1 represents an integer of 0 to 3. w1 represents an integer of 0 to 8. When p1, q1, r1 and / or w1 are 2 or more, multiple R a21 , R a22 , R a23 and / or R a25 may be the same or different.]

[0131] R a21 , R a22 , R a23 and R a25 Examples of the aliphatic hydrocarbon group in include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, and a tert-butyl group. R a24 Examples of the halogen atom in the formula include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R a24 Examples of the alkyl group in 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 an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group. R a24Examples of the alkyl group having a halogen atom in the formula (I) include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, a perfluorohexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.

[0132] L a8 and L a9 Examples of the alkanediyl group in the formula (I) include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group.

[0133] In formulas (a3-1) to (a3-3), L a4 ~L a6 are each independently preferably -O- or -O-(CH2) k3 In -CO-O-, k3 is a group in which k3 is any integer of 1 to 4, more preferably -O- and *-O-CH2-CO-O-, and even more preferably an oxygen atom. R a18 ~R a21 is preferably a methyl group. R a22 and R a23 are each independently preferably a carboxy group, a cyano group, or a methyl group. p1, q1 and r1 each independently represent an integer of preferably 0 to 2, and more preferably 0 or 1.

[0134] In formula (a3-4), R a24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group. Ra25 is preferably a carboxy group, a cyano group or a methyl group. L a7 is preferably -O- or *-OL a8 It is —CO—O—, and more preferably —O—, —O—CH 2 —CO—O— or —O—C 2 H 4 —CO—O—. w1 is preferably an integer of 0 to 2, and more preferably 0 or 1. In particular, the formula (a3-4) is preferably the formula (a3-4)'. TIFF0007763576000092.tif4326 (in the formula, R a24 , L a7 has the same meaning as above.)

[0135] Examples of the structural unit (a3) ​​include structural units derived from monomers described in JP 2010-204646 A, JP 2000-122294 A, and JP 2012-41274 A. Examples of the structural unit (a3) ​​include structural units represented by any of formulas (a3-1-1), (a3-1-2), (a3-2-1), (a3-2-2), (a3-3-1), (a3-3-2), and (a3-4-1) to (a3-4-12), and in the structural units, R in formulas (a3-1) to (a3-4) a18 , R a19 , R a20 and R a24 A structural unit in which a methyl group corresponding to the following is replaced with a hydrogen atom is preferred.

[0136] TIFF0007763576000093.tif115164

[0137] When the resin (A) contains the structural unit (a3), the total content thereof is usually 5 to 70 mol %, preferably 10 to 65 mol %, and more preferably 10 to 60 mol %, based on all structural units in the resin (A). Furthermore, the content of the structural unit (a3-1), the structural unit (a3-2), the structural unit (a3-3), or the structural unit (a3-4) is preferably 5 to 60 mol %, more preferably 5 to 50 mol %, and even more preferably 10 to 50 mol %, based on the total structural units of the resin (A).

[0138] <Structural unit (a4)> Examples of the structural unit (a4) include the following structural units. TIFF0007763576000094.tif2553[In formula (a4), R 41 represents a hydrogen atom or a methyl group. R 42 represents a saturated hydrocarbon group having 1 to 24 carbon atoms and containing a halogen atom, and -CH2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO.] R 42 Examples of the saturated hydrocarbon group represented by the formula (I) include a chain saturated hydrocarbon group, a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and a group formed by combining these groups.

[0139] Examples of the chain saturated hydrocarbon group 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 decyl group, a dodecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group. Examples of the monocyclic or polycyclic alicyclic saturated hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group; and polycyclic alicyclic saturated hydrocarbon groups such as a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* indicates a bonding position): TIFF0007763576000095.tif10146 Examples of groups formed by this combination include groups formed by combining one or more alkyl groups or one or more alkanediyl groups with one or more alicyclic saturated hydrocarbon groups, such as -alkanediyl group-alicyclic saturated hydrocarbon group, -alicyclic saturated hydrocarbon group-alkyl group, and -alkanediyl group-alicyclic saturated hydrocarbon group-alkyl group.

[0140] Examples of the structural unit (a4) include a structural unit represented by formula (a4-0), a structural unit represented by formula (a4-1), and a structural unit represented by formula (a4-4). TIFF0007763576000096.tif3844[In formula (a4-0), R 54 represents a hydrogen atom or a methyl group. L 4a represents a single bond or an alkanediyl group having 1 to 4 carbon atoms. L 3a represents a perfluoroalkanediyl group having 1 to 8 carbon atoms or a perfluorocycloalkanediyl group having 3 to 12 carbon atoms. R 64 represents a hydrogen atom or a fluorine atom.

[0141] L 4a Examples of the alkanediyl group in the formula (I) include linear alkanediyl groups such as a methylene group, an ethylene group, a propane-1,3-diyl group, and a butane-1,4-diyl group, and branched alkanediyl groups such as an ethane-1,1-diyl group, a propane-1,2-diyl group, a butane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, and a 2-methylpropane-1,2-diyl group.

[0142] L 3aExamples of the perfluoroalkanediyl group in the formula (I) include a difluoromethylene group, a perfluoroethylene group, a perfluoropropane-1,1-diyl group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group, a perfluoropropane-2,2-diyl group, a perfluorobutane-1,4-diyl group, a perfluorobutane-2,2-diyl group, a perfluorobutane-1,2-diyl group, a perfluoropentane-1,5-diyl group, a perfluoropentane-2,2-diyl group, a perfluoropentane-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-2,2-diyl group, perfluorooctane-3,3-diyl group, and perfluorooctane-4,4-diyl group. L 3a Examples of the perfluorocycloalkanediyl group in the formula (I) include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, and a perfluoroadamantanediyl group.

[0143] 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.

[0144] The structural unit (a4-0) includes the structural units shown below and R in the structural unit (a4-0) in the structural units shown below. 54 The structural unit in which a methyl group corresponding to the above is replaced with a hydrogen atom is an example. TIFF0007763576000097.tif59166

[0145] TIFF0007763576000098.tif34112

[0146] TIFF0007763576000099.tif4866[In formula (a4-1), R a41 represents a hydrogen atom or a methyl group. R a42 represents a saturated hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and -CH2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-. A a41 represents an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a group represented by formula (a-g1), a41 and R a42 At least one of the groups has a halogen atom (preferably a fluorine atom) as a substituent. TIFF0007763576000100.tif1588 [In formula (a-g1), s represents 0 or 1. A a42 and A a44 each independently represents a divalent saturated hydrocarbon group having 1 to 5 carbon atoms which may have a substituent. A a43 represents a single bond or a divalent saturated hydrocarbon group having 1 to 5 carbon atoms which may have a substituent. X a41 and X a42 each independently represents -O-, -CO-, -CO-O- or -O-CO-. However, A a42 , A a43 , A a44 , X a41 and X a42 The total number of carbon atoms is 7 or less. * indicates the bond position, and the * on the right is -O-CO-R a42 ]

[0147] R a42Examples of the saturated hydrocarbon group in include a chain saturated hydrocarbon group, a monocyclic or polycyclic saturated alicyclic hydrocarbon group, and a group formed by combining these.

[0148] Examples of the chain saturated hydrocarbon group 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 decyl group, a dodecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group. Examples of the monocyclic or polycyclic saturated alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group; and polycyclic alicyclic hydrocarbon groups such as a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* indicates a bonding position): TIFF0007763576000101.tif11159 Examples of groups formed by this combination include groups formed by combining one or more alkyl groups or one or more alkanediyl groups with one or more saturated alicyclic hydrocarbon groups, such as -alkanediyl group-saturated alicyclic hydrocarbon group, -saturated alicyclic hydrocarbon group-alkyl group, and -alkanediyl group-saturated alicyclic hydrocarbon group-alkyl group.

[0149] R a42 The substituent that may be possessed by may be at least one selected from the group consisting of a halogen atom and a group represented by formula (a-g3): Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred. TIFF0007763576000102.tif855[In formula (a-g3), X a43 represents an oxygen atom, a carbonyl group, *-O-CO- or *-CO-O- (* represents R a42 represents the bond position with ). A a45 represents a saturated hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom. * indicates the bond position.] However, R a42 -Xa43 -A a45 In R a42 If A does not have a halogen atom, a45 represents a saturated hydrocarbon group having 1 to 17 carbon atoms and at least one halogen atom.

[0150] A a45 Examples of the saturated hydrocarbon group in include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl groups; monocyclic alicyclic hydrocarbon groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups; and polycyclic alicyclic hydrocarbon groups such as decahydronaphthyl, adamantyl, norbornyl, and the following groups (* indicates a bonding position): TIFF0007763576000103.tif11158 Examples of groups formed by combination include groups formed by combining one or more alkyl groups or one or more alkanediyl groups with one or more alicyclic hydrocarbon groups, such as -alkanediyl group-alicyclic hydrocarbon group, -alicyclic hydrocarbon group-alkyl group, and -alkanediyl group-alicyclic hydrocarbon group-alkyl group.

[0151] R a42 is preferably a saturated hydrocarbon group which may have a halogen atom, and more preferably a saturated hydrocarbon group having an alkyl group having a halogen atom and / or a group represented by formula (a-g3). R a42When is a saturated hydrocarbon group having a halogen atom, it is preferably a saturated hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, still more preferably a perfluoroalkyl group having 1 to 6 carbon atoms, and particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. Examples of perfluoroalkyl groups include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Examples of perfluorocycloalkyl groups include a perfluorocyclohexyl group. R a42 is a saturated hydrocarbon group having a group represented by formula (a-g3), the number of carbon atoms contained in the group represented by formula (a-g3) is a42 The total number of carbon atoms is preferably 15 or less, more preferably 12 or less. When the group represented by formula (a-g3) is contained as a substituent, the number thereof is preferably 1.

[0152] R a42 is a saturated hydrocarbon group having a group represented by formula (a-g3), R a42 is more preferably a group represented by formula (a-g2). TIFF0007763576000104.tif872[In formula (a-g2), A a46 represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom. X a44 represents *-O-CO- or *-CO-O- (* represents A a46 represents the bond position with ). A a47 represents a saturated hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom. However, A a46 , A a47 and X a44 The total number of carbon atoms in A is 18 or less. a46 and A a47 At least one of the groups has at least one halogen atom. * indicates the bond position with the carbonyl group.]

[0153] A a46 The saturated hydrocarbon group preferably has 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. A a47 The saturated hydrocarbon group 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.

[0154] A preferred structure of the group represented by formula (a-g2) is the following structure (* indicates the bonding position with the carbonyl group): TIFF0007763576000105.tif14160

[0155] A a41 Examples of the alkanediyl group in the formula (I) include linear alkanediyl groups such as methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, and hexane-1,6-diyl; and branched alkanediyl groups such as propane-1,2-diyl, butane-1,3-diyl, 2-methylpropane-1,2-diyl, 1-methylbutane-1,4-diyl, and 2-methylbutane-1,4-diyl. A a41 Examples of the substituent in the alkanediyl group represented by the formula (I) include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms. A a41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and even more preferably an ethylene group.

[0156] A in the group represented by formula (a-g1) a42 , A a43 and A a44Examples of the divalent saturated hydrocarbon group represented by include a linear or branched alkanediyl group, a monocyclic divalent alicyclic saturated hydrocarbon group, and a group formed by combining an alkanediyl group and a divalent alicyclic saturated hydrocarbon group. Specific examples include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a 1-methylpropane-1,3-diyl group, a 2-methylpropane-1,3-diyl group, and a 2-methylpropane-1,2-diyl group. A a42 , A a43 and A a44 Examples of the substituent of the divalent saturated hydrocarbon group represented by the formula include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms. Preferably, s is 0.

[0157] In the group represented by formula (a-g1), X a42 In the following examples, * and ** each represent a bond position, and ** represents -O-CO-R a42 This is the bonding position with TIFF0007763576000106.tif47140

[0158] The structural unit represented by formula (a4-1) includes the structural units shown below and R in the structural unit represented by formula (a4-1) in the structural units shown below. a41 The structural unit in which a methyl group corresponding to the above is replaced with a hydrogen atom is an example. TIFF0007763576000107.tif154136

[0159] TIFF0007763576000108.tif59122

[0160] Examples of the structural unit represented by formula (a4-1) include a structural unit represented by formula (a4-2) and a structural unit represented by formula (a4-3). TIFF0007763576000109.tif4156[In formula (a4-2), R f5 represents a hydrogen atom or a methyl group. L 44 represents an alkanediyl group having 1 to 6 carbon atoms, and -CH2- contained in the alkanediyl group may be replaced with -O- or -CO-. R f6 represents a saturated hydrocarbon group having 1 to 20 carbon atoms and containing a fluorine atom. However, L 44 and R f6 The maximum total carbon number is 21.]

[0161] L 44 The alkanediyl group having 1 to 6 carbon atoms is A a41 Examples of the groups include the same groups as those exemplified in R f6 The saturated hydrocarbon group of R 42 Examples of the groups include the same groups as those exemplified in L 44 The alkanediyl group in the formula (I) is preferably an alkanediyl group having 2 to 4 carbon atoms, more preferably an ethylene group.

[0162] Examples of the structural unit represented by formula (a4-2) include structural units represented by formulas (a4-1-1) to (a4-1-11). f5 The structural unit represented by formula (a4-2) also includes a structural unit in which a methyl group corresponding to the following is replaced with a hydrogen atom:

[0163] TIFF0007763576000110.tif5671[In 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 contain a fluorine atom. X f12 represents *-O-CO- or *-CO-O- (* represents A f13 represents the bond position with ). Af14 represents a saturated hydrocarbon group having 1 to 17 carbon atoms which may contain a fluorine atom. However, A f13 and A f14 At least one of L has a fluorine atom, 5 , A f13 and A f14 The total number of carbon atoms in a molecule is limited to 20.

[0164] L 5 The alkanediyl group in a41 Examples of the alkanediyl group include the same groups as those exemplified as the alkanediyl group.

[0165] A f13 The divalent saturated hydrocarbon group optionally having a fluorine atom in the formula (I) is preferably a divalent chain saturated hydrocarbon group optionally having a fluorine atom and a divalent alicyclic saturated hydrocarbon group optionally having a fluorine atom, and more preferably a perfluoroalkanediyl group. Examples of the divalent chain saturated hydrocarbon group which may have a fluorine atom include alkanediyl groups such as a methylene group, an ethylene group, a propanediyl group, a butanediyl group, and a pentanediyl group; and perfluoroalkanediyl groups such as a difluoromethylene group, a perfluoroethylene group, a perfluoropropanediyl group, a perfluorobutanediyl group, and a perfluoropentanediyl group. The divalent alicyclic saturated hydrocarbon group optionally having 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.

[0166] A f14 The saturated hydrocarbon group and the saturated hydrocarbon group which may have a fluorine atom are R a42Among these, a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, an ethyl group, a perfluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a propyl group, a perfluorobutyl group, a 1,1,2,2,3,3,4,4-octafluorobutyl group, a butyl group, a perfluoropentyl group, a 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a pentyl group, Preferred are fluorinated alkyl groups such as a hexyl group, a perfluorohexyl group, a heptyl group, a perfluoroheptyl group, an octyl group, and a perfluorooctyl group, a cyclopropylmethyl group, a cyclopropyl group, a cyclobutylmethyl group, a cyclopentyl group, a cyclohexyl group, a perfluorocyclohexyl group, an adamantyl group, an adamantylmethyl group, an adamantyldimethyl group, a norbornyl group, a norbornylmethyl group, a perfluoroadamantyl group, and a perfluoroadamantylmethyl group.

[0167] In formula (a4-3), L 5 is preferably an ethylene group. A f13 The divalent saturated hydrocarbon group is preferably a group containing a divalent saturated chain hydrocarbon group having 1 to 6 carbon atoms and a divalent saturated alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a divalent saturated chain hydrocarbon group having 2 to 3 carbon atoms. A f14 The saturated hydrocarbon group is preferably a group containing a chain saturated hydrocarbon group having 3 to 12 carbon atoms and a group containing an alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, and more preferably a group containing a chain saturated hydrocarbon group having 3 to 10 carbon atoms and a group containing an alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms. f14 is preferably a group containing an alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, and more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, or an adamantyl group.

[0168] Examples of the structural unit represented by formula (a4-3) include structural units represented by formulas (a4-1'-1) to (a4-1'-11). f7 The structural unit represented by formula (a4-3) also includes a structural unit in which a methyl group corresponding to the following is replaced with a hydrogen atom:

[0169] The structural unit (a4) also includes a structural unit represented by formula (a4-4). TIFF0007763576000111.tif4466[In formula (a4-4), R f21 represents a hydrogen atom or a methyl group. A f21 is -(CH2) j1 -, -(CH2) j2 -O-(CH2) j3 -or-(CH2) j4 -CO-O-(CH2) j5 - represents. j1 to j5 each independently represent an integer of 1 to 6. R f22 represents a saturated hydrocarbon group having 1 to 10 carbon atoms and containing a fluorine atom.]

[0170] R f22 The saturated hydrocarbon group of R a42 R f22 is preferably an alkyl group having 1 to 10 carbon atoms and containing a fluorine atom or an alicyclic saturated hydrocarbon group having 1 to 10 carbon atoms and containing a fluorine atom, more preferably an alkyl group having 1 to 10 carbon atoms and containing a fluorine atom, and even more preferably an alkyl group having 1 to 6 carbon atoms and containing a fluorine atom.

[0171] In formula (a4-4), A f21 As -(CH2) j1 - is preferred, an ethylene group or a methylene group is more preferred, and a methylene group is even more preferred.

[0172] Examples of the structural unit represented by formula (a4-4) include the following structural units and structural units represented by the following formulas: f21 The structural unit in which a methyl group corresponding to the above is replaced with a hydrogen atom is an example. TIFF0007763576000112.tif86160

[0173] When the resin (A) has the structural unit (a4), the content thereof is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and even more preferably 3 to 10 mol %, based on all structural units in the resin (A).

[0174] <Structural unit (a5)> The non-leaving hydrocarbon group contained in the structural unit (a5) may be a group containing a linear, branched, or cyclic hydrocarbon group, and among these, the structural unit (a5) is preferably a group containing an alicyclic hydrocarbon group. Examples of the structural unit (a5) include a structural unit represented by formula (a5-1). TIFF0007763576000113.tif3149 [In formula (a5-1), R 51 represents a hydrogen atom or a methyl group. R 52 represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms. L 55 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and -CH2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-.]

[0175] R 52 The alicyclic hydrocarbon group in may be either monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. Examples of polycyclic alicyclic hydrocarbon groups include adamantyl and norbornyl. Examples of the aliphatic hydrocarbon group having 1 to 8 carbon atoms include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, and 2-ethylhexyl. 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.

[0176] L 55 The divalent saturated hydrocarbon group in the formula (I) includes a divalent saturated chain hydrocarbon group and a divalent saturated alicyclic hydrocarbon group, and is preferably a divalent saturated chain hydrocarbon group. Examples of the divalent chain saturated hydrocarbon group include a methylene group, an ethylene group, and an alkanediyl group such as a propanediyl group, a butanediyl group, and a 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 and cyclohexanediyl. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include adamantanediyl and norbornanediyl.

[0177] L 55 Examples of the divalent saturated hydrocarbon group represented by formula (L1-1) in which one -CH2- is replaced with -O- or -CO- include groups represented by formula (L1-1) to formula (L1-4). In the following formulae, * and ** each represent a bonding position, and * represents a bonding position with an oxygen atom. TIFF0007763576000114.tif18165 formula (L1-1), X x1 represents *-O-CO- or *-CO-O- (* represents L x1 represents the bonding position of the L x1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms. Lx2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms. However, L x1 and L x2 The total number of carbon atoms is 16 or less. In formula (L1-2), L x3 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms. L x4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms. However, L x3 and L x4 The total number of carbon atoms 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 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms. However, L x5 , L x6 and L x7 The total number of carbon atoms is 15 or less. In formula (L1-4), L x8 and L x9 represents 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, L x8 , L x9 and W x1 The total number of carbon atoms is 15 or less.

[0178] L x1 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group. L x2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond. L x3is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms. L x4 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms. L x5 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group. L x6 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group. L x7 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms. L x8 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group. L x9 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group. W x1 is preferably a divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, more preferably a cyclohexanediyl group or an adamantanediyl group.

[0179] Examples of the group represented by formula (L1-1) include the divalent groups shown below. TIFF0007763576000115.tif53136

[0180] Examples of the group represented by formula (L1-2) include the divalent groups shown below. TIFF0007763576000116.tif23130

[0181] Examples of the group represented by formula (L1-3) include the divalent groups shown below. TIFF0007763576000117.tif15145

[0182] Examples of the group represented by formula (L1-4) include the divalent groups shown below. TIFF0007763576000118.tif26114

[0183] L 55 is preferably a single bond or a group represented by formula (L1-1).

[0184] The structural unit (a5-1) includes the structural units shown below and R in the structural unit (a5-1) in the structural units shown below. 51 The structural unit in which a methyl group corresponding to the above is replaced with a hydrogen atom is an example. TIFF0007763576000119.tif77157

[0185] When the resin (A) has the structural unit (a5), the content thereof is preferably 1 to 30 mol %, more preferably 2 to 20 mol %, and even more preferably 3 to 15 mol %, based on all structural units in the resin (A).

[0186] <Structural unit (II)> The resin (A) may further contain a structural unit that decomposes upon exposure to generate an acid (hereinafter, this may be referred to as "structural unit (II)"). Specific examples of the structural unit (II) include the structural units described in JP-A-2016-79235, and the structural unit (II) is preferably a structural unit having a sulfonate group or carboxylate group and an organic cation in the side chain, or a structural unit having a sulfonio group and an organic anion in the side chain.

[0187] The structural unit having a sulfonate group or carboxylate group and an organic cation on the side chain is preferably a structural unit represented by formula (II-2-A'). TIFF0007763576000121.tif3189 [In formula (II-2-A'), X III3represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, wherein one -CH2- contained in the saturated hydrocarbon group may be replaced by -O-, -S-, or -CO-, and a hydrogen atom contained in the saturated hydrocarbon group may be replaced by a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, or a hydroxy group. A x1 represents an alkanediyl group having 1 to 8 carbon atoms, and a hydrogen atom contained in the alkanediyl group may be substituted 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.

[0188] R III3 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R III3 The alkyl group having 1 to 6 carbon atoms which may have a halogen atom and is represented by the formula: a8 Examples of the alkyl group include the same alkyl groups having 1 to 6 carbon atoms which may have a halogen atom and which are represented by the following formula: A x1 Examples of the alkanediyl group having 1 to 8 carbon atoms represented by the formula (I) include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-2,2-diyl group, a pentane-2,4-diyl group, a 2-methylpropane-1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, and a 2-methylbutane-1,4-diyl group. A x1Examples of the perfluoroalkyl group having 1 to 6 carbon atoms which may be substituted include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluorohexyl group. X III3 Examples of the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by the formula (I) include a linear or branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and these may be used in combination. Specific examples thereof include linear alkanediyl groups such as methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, and dodecane-1,12-diyl; butane-1,3-diyl, 2-methylpropane-1,3-diyl, and 2-methylpropane-1,2-diyl; divalent monocyclic alicyclic saturated hydrocarbon groups such as branched alkanediyl groups, 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; and divalent polycyclic alicyclic saturated hydrocarbon groups, such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, and the like.

[0189] Examples of saturated hydrocarbon groups in which -CH2- is replaced with -O-, -S-, or -CO- include divalent groups represented by formulae (X1) to (X53). However, the number of carbon atoms before the -CH2- in the saturated hydrocarbon group is replaced with -O-, -S-, or -CO- is 17 or less. In the following formulae, * and ** represent bonding positions, and * represents A x1 represents the bonding position with TIFF0007763576000122.tif145161

[0190] 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.

[0191] ZA + The organic cation represented by the formula (B1) is the cation Z1 + The same can be mentioned.

[0192] The structural unit represented by formula (II-2-A') is preferably a structural unit represented by formula (II-2-A). TIFF0007763576000123.tif38109 [In formula (II-2-A), R III3 , X III3 and ZA + has the same meaning as above. z2A represents an integer of 0 to 6. R III2 and R III4 each independently represents a hydrogen atom, a fluorine atom, or a perfluoroalkyl group having 1 to 6 carbon atoms; when z is 2 or more, a plurality of R III2 and R III4 may be the same as or different from each other. Q a and Q b each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.] R III2 , R III4 , Q aand Q b As the perfluoroalkyl group having 1 to 6 carbon atoms represented by the formula, the above-mentioned Q b1 Examples include the same perfluoroalkyl groups having 1 to 6 carbon atoms as those represented by the following formula:

[0193] The structural unit represented by formula (II-2-A) is preferably a structural unit represented by formula (II-2-A-1). TIFF0007763576000124.tif5576 [In formula (II-2-A-1), R III2 , R III3 , R III4 , Q a , Q b and ZA + has the same meaning as above. R III5 represents a saturated hydrocarbon group having 1 to 12 carbon atoms. z2A1 represents an integer of 0 to 6. X I2 represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms, wherein -CH2- contained in the saturated hydrocarbon group may be replaced by -O-, -S-, or -CO-, and wherein a hydrogen atom contained in the saturated hydrocarbon group may be substituted by a halogen atom or a hydroxy group. R III5 Examples of the saturated hydrocarbon group having 1 to 12 carbon atoms represented by the formula (I) include linear or branched alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group. X I2 As the divalent saturated hydrocarbon group represented by X III3 Examples of the divalent saturated hydrocarbon group include those similar to those represented by the following formula:

[0194] As the structural unit represented by formula (II-2-A-1), a structural unit represented by formula (II-2-A-2) is more preferred. TIFF0007763576000125.tif4880 [In formula (II-2-A-2), R III3, R III5 and ZA + has the same meaning as above. m and n each independently represent 1 or 2.

[0195] Examples of the structural unit represented by formula (II-2-A') include the following structural units and structural units described in WO 2012 / 050015: ZA + represents an organic cation. TIFF0007763576000126.tif150149

[0196] The structural unit having a sulfonio group and an organic anion on the side chain is preferably a structural unit represented by formula (II-1-1). TIFF0007763576000127.tif3281 [In formula (II-1-1), A II1 represents a single bond or a divalent linking group. R II1 represents a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. R II2 and R II3 each independently represents a hydrocarbon group having 1 to 18 carbon atoms; R II2 and R II3 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 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. R II1 Examples of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms represented by the formula include a phenylene group and a naphthylene group. R II2 and R II3 Examples of the hydrocarbon group represented by the formula (I) include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these groups. Examples of the alkyl group and the alicyclic hydrocarbon group include the same as those described above. Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, and a phenanthryl group. Examples of the combined group include a group in which the above-mentioned alkyl group and alicyclic hydrocarbon group are combined, aralkyl groups such as a benzyl group, aromatic hydrocarbon groups having an alkyl group (e.g., p-methylphenyl group, p-tert-butylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group), aromatic hydrocarbon groups having an alicyclic hydrocarbon group (e.g., p-cyclohexylphenyl group, p-adamantylphenyl group), and aryl-cycloalkyl groups such as a phenylcyclohexyl group. R II4 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R II4 The alkyl group having 1 to 6 carbon atoms which may have a halogen atom and is represented by the formula: a8 Examples of the alkyl group include the same alkyl groups having 1 to 6 carbon atoms which may have a halogen atom and which are represented by the following formula: A II1 Examples of the divalent linking group represented by the formula (I) include a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and -CH2- contained in the divalent saturated hydrocarbon group may be replaced by -O-, -S- or -CO-. III3 Examples include the same divalent saturated hydrocarbon groups having 1 to 18 carbon atoms as those represented by the following formula:

[0197] Examples of the cation-containing structural unit in formula (II-1-1) include structural units represented by the following formulas. TIFF0007763576000128.tif74130

[0198] TIFF0007763576000129.tif97135

[0199] A -Examples of the organic anion represented by the formula (A) include a sulfonate anion, a sulfonylimide anion, a sulfonylmethide anion, and a carboxylate anion. - The organic anion represented by the formula (I) is preferably a sulfonate anion, and examples of the sulfonate anion, sulfonylimide anion, sulfonylmethide anion, and carboxylate anion include the same anions as those contained in the salt represented by the formula (I) described above.

[0200] Examples of the structural unit represented by formula (II-1-1) include structural units represented by the following formulas. TIFF0007763576000130.tif98155

[0201] When the structural unit (II) is contained in the resin (A), the content of the structural unit (II) is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and even more preferably 3 to 10 mol %, based on the total structural units of the resin (A).

[0202] The resin (A) may have structural units other than the above-mentioned structural units, and examples of such structural units include structural units well known in the art.

[0203] The resin (A) is preferably a resin composed of the structural unit (a1) and the structural unit (s). The structural unit (a1) is preferably at least one selected from the group consisting of the structural unit (a1-0), the structural unit (a1-1), the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group and a cyclopentyl group), and the structural unit (a1-4), more preferably at least two selected from the group consisting of the structural unit (a1-1) and the structural unit (a1-2). 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 at least one selected from the group consisting of the structural unit represented by formula (a3-1), the structural unit represented by formula (a3-2), and the structural unit represented by formula (a3-4).

[0204] The structural units constituting the resin (A) may be used singly or in combination of two or more, and can be produced by a known polymerization method (e.g., radical polymerization) using monomers that lead to these structural units. The content of each structural unit in the resin (A) can be adjusted by the amount of monomer used in the polymerization. The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, even more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less, even more preferably 15,000 or less). In this specification, the weight average molecular weight is a value determined by gel permeation chromatography under the conditions described in the Examples.

[0205] <Resins other than Resin (A)> The resist composition of the present invention may further contain a resin other than the resin (A). Examples of resins other than resin (A) include resins containing the structural unit (a4) or the structural unit (a5) (hereinafter, sometimes referred to as resin (X)).

[0206] Among these, the resin (X) is preferably a resin containing the structural unit (a4), that is, a resin containing a structural unit having a fluorine atom. In the resin (X), the content of the structural unit (a4) is preferably 30 mol % or more, more preferably 40 mol % or more, and even more preferably 45 mol % or more, based on the total of all structural units in the resin (X). Examples of structural units that the resin (X) may further have include the structural unit (a2), the structural unit (a3), and structural units derived from other known monomers. Among these, the resin (X) is preferably a resin consisting only of the structural unit (a4) and / or the structural unit (a5), and more preferably a resin consisting only of the structural unit (a4).

[0207] The structural units constituting the resin (X) may be used singly or in combination of two or more, and can be produced by a known polymerization method (e.g., radical polymerization) using monomers that derive these structural units. The content of each structural unit in the resin (X) can be adjusted by the amount of monomer used in the polymerization. The weight average molecular weight of each resin (X) is independently preferably 6,000 or more (more preferably 7,000 or more) and 80,000 or less (more preferably 60,000 or less). The method for measuring the weight average molecular weight of resin (X) is the same as that for resin (A). Furthermore, when the resist composition contains resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, even more preferably 1 to 40 parts by mass, particularly preferably 2 to 30 parts by mass, and especially preferably 2 to 8 parts by mass, relative to 100 parts by mass of resin (A).

[0208] The content of resin (A) in the resist composition is preferably 80 to 99 mass% based on the solid content of the resist composition, and more preferably 90 to 99 mass%. Furthermore, when a resin other than resin (A) is contained, the total content of resin (A) and the resin other than resin (A) based on the solid content of the resist composition is preferably 80 to 99 mass% based on the solid content of the resist composition, and more preferably 90 to 99 mass%. The solid content of the resist composition and the resin content relative to the solid content can be measured using known analytical methods such as liquid chromatography or gas chromatography.

[0209] <Solvent (E)> The content of the solvent (E) in the resist composition is usually from 90 to 99.9% by mass, preferably from 92 to 99% by mass, and more preferably from 94 to 99% by mass. The content of the solvent (E) can be measured by known analytical 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; esters such as ethyl lactate, butyl acetate, amyl acetate, and ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone, and cyclohexanone; cyclic esters such as γ-butyrolactone; etc. One type of solvent (E) may be used alone, or two or more types may be used.

[0210] <Quencher (C)> Examples of the quencher (C) include basic nitrogen-containing organic compounds and salts that generate an acid that is weaker in acidity than the acid generated from the acid generator (B). The content of the quencher (C) is preferably about 0.01 to 5 mass % based on the solid content of the resist composition. The basic nitrogen-containing organic compound includes amines and ammonium salts. The amines include aliphatic amines and aromatic amines. The aliphatic amines include primary amines, secondary amines, and tertiary amines. Amines include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N,N-dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, Amine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine amine, dicyclohexylmethylamine, tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, 2,2'-methylenebisaniline, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 1,2-di(2-pyridyl)ethane Examples of the amines include 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, and bipyridine. Preferred are aromatic amines such as diisopropylaniline, and more preferred is 2,6-diisopropylaniline. Examples of the ammonium salt include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-(trifluoromethyl)phenyltrimethylammonium hydroxide, tetra-n-butylammonium salicylate, choline, and the like.

[0211] The acidity of a salt that generates an acid with a lower acidity than the acid generated from the acid generator (B) is indicated by the acid dissociation constant (pKa). A salt that generates an acid with a lower acidity than the acid generated from the acid generator (B) is a salt having an acid dissociation constant of the acid generated from the salt usually of -3 < pKa, preferably -1 < pKa < 7, and more preferably 0 < pKa < 5. Examples of the salt that generates an acid with a lower acidity than the acid generated from the acid generator (B) include salts represented by the following formula, salts represented by formula (D) described in JP-A-2015-147926 (hereinafter sometimes referred to as "weak acid inner salt (D)"), and salts described in JP-A-2012-229206, JP-A-2012-6908, JP-A-2012-72109, JP-A-2011-39502, and JP-A-2011-191745. The salt that generates an acid with a lower acidity than the acid generated from the acid generator (B) is preferably the weak acid inner salt (D). TIFF0007763576000131.tif113145

[0212] Examples of the weak acid inner salt (D) include the following salts. TIFF0007763576000132.tif95145

[0213] When the resist composition contains the quencher (C), the content of the quencher (C) is usually 0.01 to 5% by mass, preferably 0.01 to 3% by mass, in the solid content of the resist composition.

[0214] 〈Other components〉 The resist composition of the present invention may optionally contain components other than those described above (hereinafter, these may be referred to as "other components (F)"). There are no particular limitations on the other components (F), and additives known in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, and dyes, can be used.

[0215] <Preparation of Resist Composition> The resist composition of the present invention can be prepared by mixing the salt (I) and resin (A), and, if necessary, the acid generator (B), a resin other than the resin (A), the solvent (E), the quencher (C), and other components (F). The order of mixing is arbitrary and is not particularly limited. The temperature during mixing can be selected from 10 to 40°C, depending on the type of resin, the solubility of the resin in the solvent (E), and other factors. The mixing time can be selected from 0.5 to 24 hours, depending on the mixing temperature. The mixing method is also not particularly limited, and stirring and mixing can be used. After mixing the components, it is preferable to filter the mixture using a filter with a pore size of about 0.003 to 0.2 μm.

[0216] <Method for producing a resist pattern> The method for producing a resist pattern of the present invention comprises the steps of: (1) applying the resist composition of the present invention onto a substrate; (2) drying the applied composition to form a composition layer; (3) exposing the composition layer to light; (4) heating the composition layer after exposure; and (5) A step of developing the composition layer after heating is included. The resist composition can be applied to a substrate using a commonly used device such as a spin coater. Examples of the substrate include inorganic substrates such as silicon wafers. Before applying the resist composition, the substrate may be cleaned, and an anti-reflective film or the like may be formed on the substrate. The composition after coating is dried to remove the solvent and form a composition layer. Drying is carried out, for example, by evaporating the solvent using a heating device such as a hot plate (so-called pre-baking), or by using a vacuum device. The heating temperature is preferably 50 to 200°C, and the heating time is preferably 10 to 180 seconds. The pressure during vacuum drying is preferably 1 to 1.0 x 10 5 It is preferable that the pressure is about Pa. The resulting composition layer is typically exposed using an exposure machine. The exposure machine may be an immersion exposure machine. Various exposure light sources can be used, including those that emit ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), and F2 excimer laser (wavelength 157 nm); those that convert the wavelength of laser light from a solid-state laser source (such as a YAG or semiconductor laser) to emit harmonic laser light in the far ultraviolet or vacuum ultraviolet range; and those that irradiate with electron beams or extreme ultraviolet light (EUV). In this specification, irradiation with these types of radiation may be collectively referred to as "exposure." During exposure, exposure is typically performed through a mask corresponding to the desired pattern. When the exposure light source is an electron beam, exposure may be performed by direct writing without using a mask. The composition layer after exposure is subjected to a heat treatment (so-called post-exposure bake) to promote the deprotection reaction of the acid labile groups. The heating temperature is usually about 50 to 200°C, preferably about 70 to 150°C. The heated composition layer is usually developed using a developer in a developing device. Development methods include dipping, puddling, spraying, and dynamic dispensing. The development temperature is preferably, for example, 5 to 60°C, and the development time is preferably, for example, 5 to 300 seconds. By selecting the type of developer as follows, a positive resist pattern or a negative resist pattern can be produced. When a positive resist pattern is produced from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be any of various alkaline aqueous solutions used in this field. Examples include aqueous solutions of tetramethylammonium hydroxide and (2-hydroxyethyl)trimethylammonium hydroxide (commonly known as choline). The alkaline developer may also contain a surfactant. After development, the resist pattern is preferably washed with ultrapure water, and then water remaining on the substrate and pattern is removed. When a negative resist pattern is produced from the resist composition of the present invention, a developer containing an organic solvent (hereinafter sometimes referred to as an "organic developer") is used as the developer. Examples of organic solvents contained in organic developers include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycol ether solvents such as propylene glycol monomethyl ether; amide solvents such as N,N-dimethylacetamide; and aromatic hydrocarbon solvents such as anisole. 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 even more preferably substantially only the organic solvent. Among these, the organic developer is preferably a developer containing butyl acetate and / or 2-heptanone. The total content of butyl acetate and 2-heptanone in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably substantially only butyl acetate and / or 2-heptanone. The organic developer may contain a surfactant and a small amount of water. During development, development may be stopped by replacing the organic developer with a different type of solvent. The developed resist pattern is preferably washed with a rinse solution. There are no particular limitations on the rinse solution as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, preferably an alcohol solvent or an ester solvent. After cleaning, it is preferable to remove the rinse liquid remaining on the substrate and the pattern.

[0217] <Application> The resist composition of the present invention is suitable as a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, and is particularly suitable as a resist composition for electron beam (EB) exposure or a resist composition for EUV exposure, and is useful for semiconductor microfabrication. [Example]

[0218] The present invention will be explained in more detail with reference to examples. In the examples, "%" and "parts" representing the content or amount used are by mass unless otherwise specified. The weight-average molecular weight is a value determined by gel permeation chromatography under the following analytical conditions: Column: TSKgel Multipore HXL-M x 3 + guard column (Tosoh Corporation) Eluent: tetrahydrofuran Flow rate: 1.0mL / min Detector: RI detector Column temperature: 40℃ Injection volume: 100μl Molecular weight standard: Standard polystyrene (Tosoh Corporation) The structure of the compound was confirmed by measuring the molecular ion peak using mass spectrometry (LC: Agilent 1100, MASS: Agilent LC / MSD). In the following examples, the value of this molecular ion peak is indicated by "MASS".

[0219] Example 1: Synthesis of salt represented by formula (I-2) 1.58 parts of the salt represented by formula (I-2-a), 1.00 parts of the compound represented by formula (I-2-b), and 10 parts of dimethylformamide were mixed and stirred at 23 ° C. for 30 minutes. 0.44 parts of potassium carbonate was added to the resulting mixture, and the mixture was stirred at 23 ° C. for 30 minutes, followed by further stirring at 90 ° C. for 3 hours to obtain a mixture containing the salt represented by formula (I-2-c). The resulting mixture was cooled to 23 ° C., and 12 parts of a 5% aqueous oxalic acid solution was added and stirred at 23 ° C. for 30 minutes. 2.00 parts of the salt represented by formula (I-2-d) was then added and stirred at 23 ° C. for 7 hours. 30 parts of chloroform and 30 parts of ion-exchanged water were added to the resulting reaction mixture, and the mixture was stirred at 23 ° C. for 30 minutes, followed by separation to separate the organic layer. To the obtained organic layer, 30 parts of ion-exchanged water was added, and the mixture was stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. This water washing procedure was repeated seven times. The obtained organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue. The mixture was stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 2.02 parts of the salt represented by formula (I-2). MASS(ESI(+)Spectrum):M + 481.0 MASS(ESI(-)Spectrum):M - 339.1

[0220] Example 2: Synthesis of salt represented by formula (I-3) 1.58 parts of the salt represented by formula (I-2-a), 1.00 parts of the compound represented by formula (I-2-b), and 10 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. 0.44 parts of potassium carbonate was added to the resulting mixture, which was then stirred at 23°C for 30 minutes, followed by further stirring at 90°C for 3 hours to obtain a mixture containing the salt represented by formula (I-2-c). The resulting mixture was cooled to 23°C, and 12 parts of a 5% aqueous oxalic acid solution was added. The mixture was then stirred at 23°C for 30 minutes. 1.93 parts of the salt represented by formula (I-3-d) was then added and stirred at 23°C for 7 hours. 30 parts of chloroform and 30 parts of ion-exchanged water were added to the resulting reaction mixture, which was then stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. To the obtained organic layer, 30 parts of ion-exchanged water was added, and the mixture was stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. This water washing procedure was repeated seven times. The obtained organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue. The mixture was stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 2.24 parts of the salt represented by formula (I-3). MASS(ESI(+)Spectrum):M + 481.0 MASS(ESI(-)Spectrum):M - 323.0

[0221] Example 3: Synthesis of salt represented by formula (I-14) 1.58 parts of the salt represented by formula (I-2-a), 1.00 parts of the compound represented by formula (I-2-b), and 10 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. 0.44 parts of potassium carbonate was added to the resulting mixture, which was then stirred at 23°C for 30 minutes, followed by further stirring at 90°C for 3 hours to obtain a mixture containing the salt represented by formula (I-2-c). The resulting mixture was cooled to 23°C, and 12 parts of a 5% aqueous oxalic acid solution was added. The mixture was then stirred at 23°C for 30 minutes. 1.93 parts of the salt represented by formula (I-14-d) was then added and stirred at 23°C for 7 hours. 30 parts of chloroform and 30 parts of ion-exchanged water were added to the resulting reaction mixture, which was then stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. To the obtained organic layer, 30 parts of ion-exchanged water was added, and the mixture was stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. This water washing procedure was repeated seven times. The obtained organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue. The mixture was stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 1.99 parts of the salt represented by formula (I-14). MASS(ESI(+)Spectrum):M + 481.0 MASS(ESI(-)Spectrum):M - 323.1

[0222] Example 4: Synthesis of salt represented by formula (I-437) 1.24 parts of the compound represented by formula (I-437-b) and 10 parts of tetrahydrofuran were mixed and stirred at 23°C for 30 minutes, then cooled to 5°C, and 0.14 parts of sodium hydride was added. 1.82 parts of the salt represented by formula (I-2-a) were added to the resulting mixture, and the mixture was stirred at 5°C for 3 hours. 6.30 parts of 1N hydrochloric acid were added to the resulting mixture, and the mixture was heated to 23°C and stirred at 23°C for 30 minutes. 30 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. The resulting organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue. The mixture was stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 2.11 parts of the salt represented by formula (I-437-c). 1.00 parts of the salt represented by formula (I-437-c), 0.81 parts of the salt represented by formula (I-2-d), and 20 parts of chloroform were added, and the mixture was stirred at 23°C for 3 hours. 15 parts of ion-exchanged water was added to the resulting reaction mixture, and the mixture was stirred at 23°C for 30 minutes. The organic layer was separated and the organic layer was isolated. 15 parts of ion-exchanged water was added to the resulting organic layer, and the mixture was stirred at 23°C for 30 minutes. The organic layer was separated and the organic layer was isolated. This water washing procedure was repeated five times. The obtained organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, followed by stirring at 23°C for 30 minutes. The supernatant was then removed, and the mixture was concentrated to obtain 1.12 parts of the salt represented by formula (I-437). MASS(ESI(+)Spectrum):M + 499.0 MASS(ESI(-)Spectrum):M - 339.1

[0223] Example 5: Synthesis of salt represented by formula (I-438) 1.24 parts of the compound represented by formula (I-437-b) and 10 parts of tetrahydrofuran were mixed and stirred at 23°C for 30 minutes, then cooled to 5°C, and 0.14 parts of sodium hydride was added. 1.82 parts of the salt represented by formula (I-2-a) were added to the resulting mixture, and the mixture was stirred at 5°C for 3 hours. 6.30 parts of 1N hydrochloric acid were added to the resulting mixture, and the mixture was heated to 23°C and stirred at 23°C for 30 minutes. 30 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. The resulting organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue. The mixture was stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 2.11 parts of the salt represented by formula (I-437-c). 1.00 parts of the salt represented by formula (I-437-c), 0.80 parts of the salt represented by formula (I-3-d), and 20 parts of chloroform were added, and the mixture was stirred at 23°C for 3 hours. 15 parts of ion-exchanged water was added to the resulting reaction mixture, and the mixture was stirred at 23°C for 30 minutes. The organic layer was separated and the organic layer was isolated. 15 parts of ion-exchanged water was added to the resulting organic layer, and the mixture was stirred at 23°C for 30 minutes. The organic layer was separated and the organic layer was isolated. This water washing procedure was repeated five times. The obtained organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, followed by stirring at 23°C for 30 minutes. The supernatant was then removed, and the mixture was concentrated to obtain 1.35 parts of the salt represented by formula (I-438). MASS(ESI(+)Spectrum):M + 499.0 MASS(ESI(-)Spectrum):M - 323.0

[0224] Example 6: Synthesis of salt represented by formula (I-448) 1.00 parts of the salt represented by formula (I-437-c), 1.07 parts of the salt represented by formula (I-448-d), and 20 parts of chloroform were added and stirred at 23°C for 3 hours. 15 parts of ion-exchanged water was added to the resulting reaction mixture, and the mixture was stirred at 23°C for 30 minutes. The organic layer was separated and the resulting organic layer was isolated. 15 parts of ion-exchanged water was added to the resulting organic layer, and the mixture was stirred at 23°C for 30 minutes. The organic layer was then separated and the resulting organic layer was isolated. This water washing procedure was repeated five times. The resulting organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue. The mixture was stirred at 23°C for 30 minutes. The supernatant was removed, and the resulting mixture was concentrated to obtain 1.44 parts of the salt represented by formula (I-448). MASS(ESI(+)Spectrum):M + 499.0 MASS(ESI(-)Spectrum):M - 467.1

[0225] Example 7: Synthesis of salt represented by formula (I-440) 1.00 parts of the salt represented by formula (I-437-c), 1.20 parts of the salt represented by formula (I-440-d), and 20 parts of chloroform were added and stirred at 23°C for 3 hours. 15 parts of ion-exchanged water was added to the resulting reaction mixture, and the mixture was stirred at 23°C for 30 minutes. The organic layer was separated and the resulting organic layer was isolated. 15 parts of ion-exchanged water was added to the resulting organic layer, and the mixture was stirred at 23°C for 30 minutes. The organic layer was then separated and the resulting organic layer was isolated. This water washing procedure was repeated five times. The resulting organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were 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 obtain 1.23 parts of the salt represented by formula (I-440). MASS(ESI(+)Spectrum):M + 499.0 MASS(ESI(-)Spectrum):M - 517.1

[0226] Example 8: Synthesis of salt represented by formula (I-34) 0.96 parts of the compound represented by formula (I-34-b) and 10 parts of tetrahydrofuran were mixed and stirred at 23°C for 30 minutes, then cooled to 5°C, and 0.14 parts of sodium hydride was added. 1.82 parts of the salt represented by formula (I-2-a) were added to the resulting mixture, and the mixture was stirred at 5°C for 3 hours. 6.30 parts of 1N hydrochloric acid were added to the resulting mixture, and the mixture was heated to 23°C and stirred at 23°C for 30 minutes. 30 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. The resulting organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue. The mixture was stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 1.09 parts of the salt represented by formula (I-34-c). 0.90 parts of the salt represented by formula (I-42-c), 1.20 parts of the salt represented by formula (I-440-d), and 20 parts of chloroform were added, and the mixture was stirred at 23°C for 3 hours. 15 parts of ion-exchanged water was added to the resulting reaction mixture, and the mixture was stirred at 23°C for 30 minutes. The organic layer was separated and the organic layer was isolated. 15 parts of ion-exchanged water was added to the resulting organic layer, and the mixture was stirred at 23°C for 30 minutes. The organic layer was separated and the organic layer was isolated. This water washing procedure was repeated five times. The obtained organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, followed by stirring at 23°C for 30 minutes. The supernatant was then removed, and the mixture was concentrated to obtain 1.05 parts of the salt represented by formula (I-34). MASS(ESI(+)Spectrum):M + 445.1 MASS(ESI(-)Spectrum):M - 517.1

[0227] Example 9: Synthesis of salt represented by formula (I-498) 2.46 parts of the compound represented by formula (I-498-b) and 10 parts of tetrahydrofuran were mixed and stirred at 23°C for 30 minutes, then cooled to 5°C, and 0.14 parts of sodium hydride was added. 1.82 parts of the salt represented by formula (I-2-a) were added to the resulting mixture, and the mixture was stirred at 5°C for 3 hours. 6.30 parts of 1N hydrochloric acid were added to the resulting mixture, and the mixture was heated to 23°C and stirred at 23°C for 30 minutes. 30 parts of chloroform and 15 parts of ion-exchanged water were added to the resulting mixture, and the mixture was stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. The resulting organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue. The mixture was stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 1.69 parts of the salt represented by formula (I-498-c). 1.44 parts of the salt represented by formula (I-498-c), 1.20 parts of the salt represented by formula (I-440-d), and 20 parts of chloroform were added, and the mixture was stirred at 23°C for 3 hours. 15 parts of ion-exchanged water was added to the resulting reaction mixture, and the mixture was stirred at 23°C for 30 minutes. The organic layer was separated and the organic layer was isolated. 15 parts of ion-exchanged water was added to the resulting organic layer, and the mixture was stirred at 23°C for 30 minutes. The organic layer was separated and the organic layer was isolated. This water washing procedure was repeated five times. The obtained organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, followed by stirring at 23°C for 30 minutes. The supernatant was then removed, and the mixture was concentrated to obtain 1.89 parts of the salt represented by formula (I-498). MASS(ESI(+)Spectrum):M + 732.8 MASS(ESI(-)Spectrum):M - 517.1

[0228] Example 10: Synthesis of salt represented by formula (I-5) 1.58 parts of the salt represented by formula (I-2-a), 1.00 parts of the compound represented by formula (I-2-b), and 10 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. 0.44 parts of potassium carbonate was added to the resulting mixture, which was then stirred at 23°C for 30 minutes, followed by further stirring at 90°C for 3 hours to obtain a mixture containing the salt represented by formula (I-2-c). The resulting mixture was cooled to 23°C, and 12 parts of a 5% aqueous oxalic acid solution was added. The mixture was then stirred at 23°C for 30 minutes. 2.91 parts of the salt represented by formula (I-440-d) were then added and stirred at 23°C for 7 hours. 30 parts of chloroform and 30 parts of ion-exchanged water were added to the resulting reaction mixture, which was then stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. To the obtained organic layer, 30 parts of ion-exchanged water was added, and the mixture was stirred at 23°C for 30 minutes, followed by separation to separate the organic layer. This water washing procedure was repeated seven times. The obtained organic layer was concentrated, and then 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue. The mixture was stirred at 23°C for 30 minutes, after which the supernatant was removed and the mixture was concentrated to obtain 2.88 parts of the salt represented by formula (I-5). MASS(ESI(+)Spectrum):M + 481.0 MASS(ESI(-)Spectrum):M - 517.1

[0229] Resin synthesis The compounds (monomers) used in the synthesis of resin (A) are shown below. Hereinafter, these compounds will be referred to as "monomer (a1-1-3)" etc. according to their formula numbers. TIFF0007763576000143.tif3997

[0230] Synthesis Example 1 [Synthesis of Resin A1] Monomers (a1-4-2), (a1-1-3), and (a1-2-6) were used and mixed in a molar ratio of 38:24:38 [monomer (a1-4-2):monomer (a1-1-3):monomer (a1-2-6)]. This monomer mixture was then mixed with 1.5 times the total mass of all monomers of methyl isobutyl ketone. Azobisisobutyronitrile was added as an initiator to the resulting mixture in an amount of 7 mol% based on the total moles of all monomers. The mixture was heated at 85°C for approximately 5 hours to polymerize. A p-toluenesulfonic acid solution was then added to the polymerization reaction mixture, which was stirred for 6 hours and then separated. The resulting organic layer was poured into a large amount of n-heptane to precipitate a resin. The resin was then filtered and recovered, yielding a polymer with a weight-average molecular weight of approximately 5.3 x 10. 3 Resin A1 (copolymer) having the following structural units was obtained in a yield of 78%. TIFF0007763576000144.tif29126

[0231] Synthesis Example 2 [Synthesis of Resin A2] Monomers (a1-4-2), (a1-1-3), and (a1-2-6) were used and mixed in a molar ratio of 49:21:30 [monomer (a1-4-2):monomer (a1-1-3):monomer (a1-2-6)]. This monomer mixture was then mixed with 1.5 times the total mass of all monomers of methyl isobutyl ketone. Azobisisobutyronitrile was added as an initiator to the resulting mixture in an amount of 7 mol% based on the total moles of all monomers. The mixture was heated at 85°C for approximately 5 hours to polymerize. A p-toluenesulfonic acid solution was then added to the polymerization reaction mixture, which was stirred for 6 hours and then separated. The resulting organic layer was poured into a large amount of n-heptane to precipitate a resin. The resin was then filtered and recovered, yielding a polymer with a weight-average molecular weight of approximately 5.8 x 10. 3 Resin A2 (copolymer) having the following structural units was obtained in a yield of 84%. TIFF0007763576000145.tif29126

[0232] Synthesis Example 3 [Synthesis of Resin A3] Monomer (a1-4-2) and monomer (a1-2-6) were used as monomers, and they were mixed in a molar ratio of 49:51 [monomer (a1-4-2):monomer (a1-2-6)]. Furthermore, methyl isobutyl ketone was added to this monomer mixture in an amount of 1.5 times the total mass of all monomers. Azobisisobutyronitrile was added as an initiator to the resulting mixture in an amount of 7 mol% based on the total moles of all monomers, and the mixture was heated at 85°C for approximately 5 hours to polymerize. An aqueous solution of p-toluenesulfonic acid was then added to the polymerization reaction mixture, which was stirred for 6 hours and then separated. The resulting organic layer was poured into a large amount of n-heptane to precipitate a resin, which was then filtered and recovered, yielding a polymer with a weight-average molecular weight of approximately 5.9 x 10. 3 Resin A3 (copolymer) having the following structural units was obtained in a yield of 88%. TIFF0007763576000146.tif2791

[0233] <Preparation of Resist Composition> As shown in Table 2, the following components were mixed and the resulting mixture was filtered through a fluororesin filter with a pore size of 0.2 μm to prepare a resist composition. [Table 2]

[0234] <Resin> A1 to A3, Resin A1 to Resin A3 <Salt (I)> I-2: A salt represented by formula (I-2) I-3: A salt represented by formula (I-3) I-5: A salt represented by formula (I-5) I-14: Salt represented by formula (I-14) I-34: A salt represented by formula (I-34) I-437: A salt represented by the formula (I-437) I-438: A salt represented by the formula (I-438) I-440: A salt represented by the formula (I-440) I-448: A salt represented by the formula (I-448) I-498: A salt represented by the formula (I-498) <Acid generator> IX-1: Salt represented by formula (IX-1) (synthesized according to the examples in WO2017 / 135003 pamphlet) TIFF0007763576000148.tif2669<Quencher (C)> C1: Synthesized by the method described in JP 2011-39502 A TIFF0007763576000149.tif4349<solvent> Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 100 parts γ-butyrolactone 5 parts

[0235] (Electron beam exposure evaluation of resist composition) A 6-inch silicon wafer was treated with hexamethyldisilazane on a direct hot plate at 90°C for 60 seconds. The resist composition was spin-coated onto the silicon wafer so that the composition layer had a thickness of 0.04 μm. The wafer was then pre-baked on a direct hot plate for 60 seconds at the temperature shown in the "PB" column in Table 2 to form a composition layer. A contact hole pattern (hole pitch 40 nm / hole diameter 17 nm) was directly written on the composition layer formed on the wafer using an electron beam lithography machine ("ELS-F125 125 keV" manufactured by Elionix Co., Ltd.) by gradually changing the exposure dose. After exposure, post-exposure baking was performed on a hot plate for 60 seconds at the temperature shown in the "PEB" column in Table 2, and then puddle development was performed for 60 seconds in a 2.38 mass % aqueous tetramethylammonium hydroxide solution to obtain a resist pattern.

[0236] In the resist pattern obtained after development, the exposure dose at which the hole diameter formed using the mask was 17 nm was defined as the effective sensitivity.

[0237] <CD Uniformity (CDU) Evaluation> At the effective sensitivity, the hole diameter of the pattern formed with a mask having a hole diameter of 17 nm was measured 24 times for each hole, and the average value was defined as the average hole diameter of one hole. Using as the population the average hole diameters of patterns formed with masks having a hole diameter of 55 nm measured at 400 locations within the same wafer, the standard deviation was determined. The results are shown in Table 3. The numerical values in parentheses indicate the standard deviation (nm).

Table 3

Industrial Applicability

[0238] Since the resist composition of the present invention can obtain a resist pattern having good CD uniformity (CDU), it is suitable for semiconductor microfabrication and is extremely useful industrially.

Claims

1. A salt represented by formula (I): [In formula (I), R １ , R ２ and R ３ each independently represents an iodine atom or a fluorine atom. The bonding positions of R 1 , R 2 and R 3 on the benzene ring are 4-positions relative to the bonding positions of X 1 , X 2 and X 3 . R ４ , R ５ , R ６ , R ７ , R ８ and R ９ each independently represents a halogen atom, a hydroxy group, a haloalkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 6 carbon atoms, and —CH 2 - may be replaced by -O- or -CO-. X １ , X ２ and X ３ each independently represents an oxygen atom or a sulfur atom. m1 represents 1 or 2, and when m1 is 2, the groups in the parentheses may be the same or different. m2 represents 0 or 1. m3 represents 0 or 1. m4 represents an integer of 0 to 4, and when m4 is 2 or more, a plurality of R ４ may be the same or different from each other. m5 represents an integer of 0 to 4, and when m5 is 2 or more, a plurality of R ５ may be the same or different from each other. m6 represents an integer of 0 to 4, and when m6 is 2 or more, a plurality of R ６ may be the same or different from each other. m7 represents an integer of 0 to 2, and when m7 is 2, a plurality of R ７ may be the same or different from each other. m8 represents an integer of 0 to 2, and when m8 is 2, a plurality of R ８ may be the same or different from each other. m9 represents an integer of 0 to 2, and when m9 is 2, a plurality of R ９ may be the same or different from each other. However, 1≦m1+m7≦4, 0≦m2+m8≦3, and 0≦m3+m9≦3. AI － represents an anion represented by formula (IA). [In formula (IA), Q １ and Q ２ each independently represents a fluorine atom. L １ represents a group represented by either formula (b1-1) or formula (b1-2). Y １ represents an alicyclic hydrocarbon group having 10 to 18 carbon atoms and having 1 to 6 substituents (the alicyclic hydrocarbon group has 1 to 4 —CH ２ - is -O-, -SO ２ - or -CO-), or an alicyclic hydrocarbon group having 10 to 18 carbon atoms which may have 1 to 6 substituents (1 to 4 of the -CH ２ - is -O-, -SO ２ - or -CO-, the alicyclic hydrocarbon group contains an adamantane ring, The substituents include a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, -(CH ２ ) ｊａ -CO-O-R ｂ１ group or -(CH ２ ) ｊａ -O-CO-R ｂ１ group (in the formula, R ｂ１ represents an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a group combining these. ja represents an integer of 0 to 3. -CH contained in the alkyl group and the alicyclic hydrocarbon group ２ 1 to 4 of - are -O-, -S(O) ２ - or -CO- may be replaced. [In formula (b1-1), L b2 represents a single bond. L b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and —CH ２ - may be replaced by -O- or -CO-. However, L b2 and L b3 The total number of carbon atoms is 22 or less. In formula (b1-2), L b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom. L b5 represents a single bond. However, L b4 and L b5 The total number of carbon atoms is 22 or less. * and ** represent binding sites, * represents -Y １ represents the binding site with

2. X １ , X ２ and X ３ The salt according to claim 1, wherein is an oxygen atom.

3. An acid generator comprising the salt according to claim 1 or 2.

4. A resist composition comprising the acid generator according to claim 3 and a resin containing a structural unit having an acid labile group.

5. 5. The resist composition according to claim 4, wherein the structural unit having an acid labile group comprises at least two structural units represented by formula (a1-1) and formula (a1-2). [In formula (a1-1) and formula (a1-2), L a1 and L a2 are each independently —O— or *—O—(CH ２ ) k1 represents —CO—O—, k1 represents an integer of 1 to 7, and * represents the bonding position with —CO—. R a4 and R a5 each independently represents a hydrogen atom or a methyl group. R a6 and R a7 each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof. m1 represents an integer of 0 to 14. n1 represents an integer of 0 to 10. n1′ represents an integer of 0 to 3.]

6. 6. The resist composition according to claim 4, further comprising a salt that generates an acid that is weaker in acidity than the acid generated from the acid generator.

7. (1) a step of applying the resist composition according to any one of claims 4 to 6 onto a substrate; (2) a step of drying the applied composition to form a composition layer; (3) exposing the composition layer to light; (4) a step of heating the composition layer after exposure; and (5) developing the composition layer after heating; A method for producing a resist pattern comprising:

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