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

Abstract

To provide a salt, an acid generator and a resist composition comprising the same, making it possible to produce a resist pattern having excellent CD uniformity (CDU).SOLUTION: The present invention discloses a dibenzothiophenium salt or the like having a specific structure with a specific counter anion, produced from compounds illustrated by the following formulae, and a resist composition containing the same.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a salt for an acid generator used in the microfabrication of semiconductors, 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. Patent document 2 (TIFF0007867324000001.tif2683) describes a salt represented by the following formula, and a resist composition containing the salt as an acid generator. TIFF0007867324000002.tif3586 [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-015713 [Patent Document 2] Japanese Patent Publication No. 2018-118962 [Overview of the project] [Problems that the invention aims to solve]

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

[0005] This invention includes the following inventions. [1] A salt represented by formula (I). TIFF0007867324000003.tif75102 [In formula (I), R 1 , R 2 and R 3Each independently represents an iodine atom, a fluorine atom, or a C1-C12 fluoroalkyl group. R 4 、R 5 、R 6 、R 7 、R 8 及びR 9 Each independently represents a halogen atom, a hydroxy group, a C1-C12 haloalkyl group, or a C1-C18 hydrocarbon group, and the -CH2- contained in the haloalkyl group and the hydrocarbon group may be replaced by -O-, -CO-, -CO-, -S-, or -SO2-. X 1 、X 2 及びX 3 Each independently represents an oxygen atom or a sulfur atom. m1 represents any integer from 0 to 5. When m1 is 2 or more, the groups within multiple parentheses may be the same as or different from each other. m2 represents any integer from 0 to 4. When m2 is 2 or more, the groups within multiple parentheses may be the same as or different from each other. m3 represents any integer from 0 to 4. When m3 is 2 or more, the groups within multiple parentheses may be the same as or different from each other. m4 represents any integer from 0 to 4. When m4 is 2 or more, the plurality of R 4 may be the same as or different from each other. m5 represents any integer from 0 to 4. When m5 is 2 or more, the plurality of R 5 may be the same as or different from each other. m6 represents any integer from 0 to 4. When m6 is 2 or more, the plurality of R 6 may be the same as or different from each other. m7 represents any integer from 0 to 5. When m7 is 2 or more, the plurality of R 7 may be the same as or different from each other. m8 represents any integer from 0 to 4. When m8 is 2 or more, the plurality of R 8 may be the same as or different from each other. m9 represents any integer from 0 to 4. When m9 is 2 or more, the plurality of R9 They may be identical or different from one another. However, 0 ≤ m1 + m7 ≤ 5, 0 ≤ m2 + m8 ≤ 4, 0 ≤ m3 + m9 ≤ 4, At least one of m1, m2, and m3 represents an integer greater than or equal to 1. X 4 -CH2-, -O-, -S-, -CO-, -SO-, or -SO2- represent single bonds. AI - This represents an organic anion. [2]X 1 , X 2 and X 3 The salt described in [1] is an oxygen atom. [3] AI - The salt described in [1] or [2] is a sulfonate anion, a sulfonylimide anion, a sulfonylmethide anion, or a carboxylic acid anion. [4] AI - The salt is a sulfonate anion, and a sulfonate anion is an anion represented by formula (IA) as described in any of the following [1]-[3]. TIFF0007867324000004.tif2453[In formula (IA), Q 1 and Q 2 Each of these independently represents either 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, and the -CH2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups. Y 1 This represents a methyl group which may have substituents or an alicyclic hydrocarbon group having 3 to 24 carbon atoms which may have substituents, and the -CH2- contained in the alicyclic hydrocarbon group may be replaced with -O-, -SO2-, or -CO-. An acid generator containing a salt described in any of [5][1] to [4]. A resist composition containing the acid generator described in [6][5] and a resin having an acid-unstable group. [7] The resist composition according to [6], wherein the resin having an acid-labile group contains at least one selected from the group consisting of a structural unit represented by formula (a1-1) and a structural unit represented by formula (a1-2). TIFF0007867324000005.tif3886[In formula (a1-1) and formula (a1-2), L a1 and L a2 each independently represents -O- or *-O-(CH2) k1 -CO-O-, k1 represents an integer from 1 to 7, and * represents a bond to -CO-. R a4 and R a5 each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. R a6 and R a7 each independently represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group combining these. m1 represents an integer from 0 to 14. n1 represents an integer from 0 to 10. [[ID=^27]] n1’ represents an integer from 0 to 3.] [8] The resist composition according to [6] or [7], wherein the resin having an acid-labile group contains a structural unit represented by formula (a2-A). TIFF0007867324000006.tif4653[In formula (a2-A), R a50 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. R a51 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or a methacryloyloxy group. A a50 represents a single bond or* -X a51 -(A a52 -X a52 ) nb - represents, and * represents the bonding site with the carbon atom to which -R a50 is bonded. A a52 represents an alkanediyl group having 1 to 6 carbon atoms. X a51 and X a52 each independently represent -O-, -CO-O- or -O-CO-. nb represents 0 or 1. mb represents any integer from 0 to 4. When mb is any integer of 2 or more, a plurality of R a51 may be the same as or different from each other. A resist composition according to any one of [6] to [8], further containing a salt that generates an acid having a lower acidity than the acid generated from the [9] acid generator.

[10] (1) A step of applying the resist composition according to any one of [6] to [9] onto a substrate, (2) A step of drying the applied composition to form a composition layer,​​​​​​​​​​​​​​​​​​​In this specification, "(meth)acrylic monomer" means "at least one of acrylic monomers and methacrylic monomers." The notations "(meth)acrylate" and "(meth)acrylic acid" have the same meaning. For groups described herein that can take both linear and branched structures, either is acceptable. When a -CH2- contained in a hydrocarbon group, etc., is replaced by -O-, -S-, -CO-, or -SO2-, the same example shall apply to each group. "Combined group" means a group formed by bonding two or more of the exemplified groups, and the valences of these groups may be appropriately changed depending on the bonding configuration. "Derived from" or "derived from" means that a polymerizable C=C bond contained in the molecule becomes a -CC- group through polymerization. If stereoisomers exist, all stereoisomers are included.

[0008] <Salt represented by formula (I)> This invention relates to a salt represented by formula (I) (hereinafter sometimes referred to as "salt (I)"). In salts (I), the negatively charged side is sometimes called the "anion (I)," and the positively charged side is sometimes called the "cation (I)." TIFF0007867324000007.tif80102[In this formula, all symbols have the same meaning as described above.]

[0009] R 1 , R 2 and R 3 In this context, a C1-C12 alkyl fluoride refers to an alkyl group having a fluorine atom and having C1-C6 atoms, such as a C1-C6 perfluoroalkyl group (trifluoromethyl group, pentafluoroethyl group, heptafluoropropyl group, nonafluorobutyl group), as well as 2,2,2-trifluoroethyl group, 3,3,3-trifluoropropyl group, 4,4,4-trifluorobutyl group, and 3,3,4,4,4-pentafluorobutyl group. The number of carbon atoms in the alkyl fluoride is preferably 1-6, more preferably 1-4, and even more preferably 1-3. 4 , R 5 , R 6 , R 7, R 8 and R 9 Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms. R 4 , R 5 , R 6 , R 7 , R 8 and R 9 In this context, a C1-C12 haloalkyl group refers to an alkyl group having a halogen atom and containing C1-C12 atoms, such as a chloromethyl group, bromomethyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group, and perfluorobutyl group. The number of carbon atoms in the haloalkyl group is preferably 1-9, more preferably 1-6, and even more preferably 1-4. R 4 , R 5 , R 6 , R 7 , R 8 and R 9 Examples of hydrocarbon groups having 1 to 18 carbon atoms include chain hydrocarbon groups such as alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these. The alkyl group can be a linear or branched alkyl group, and examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, octyl, and nonyl groups. The number of carbon atoms in the alkyl group is preferably 1 to 12, more preferably 1 to 9, even more preferably 1 to 6, and even more preferably 1 to 4. The alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and cyclodecyl. Examples of polycyclic alicyclic hydrocarbon groups include decahydronaphthyl, adamantyl, and norbornyl. The number of carbon atoms in the alicyclic hydrocarbon group is preferably 3 to 18, more preferably 3 to 16, and even more preferably 3 to 12. Specifically, the following groups are examples of alicyclic hydrocarbon groups. The bonding site can be at any position. TIFF0007867324000008.tif44168 Examples of aromatic hydrocarbon groups include phenyl groups, naphthyl groups, biphenyl groups, anthryl groups, phenanthryl groups, and binaphthyl groups. The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 18, more preferably 6 to 14, and even more preferably 6 to 10. Groups formed by combining these groups include groups formed by combining an aromatic hydrocarbon group with a chain hydrocarbon group (e.g., aromatic hydrocarbon group-alkanediyl group-*, alkyl group-aromatic hydrocarbon group-*), groups formed by combining an alicyclic hydrocarbon group with a chain hydrocarbon group (e.g., alicyclic hydrocarbon group-alkanediyl group-*, alkyl group-alicyclic hydrocarbon group-*), and groups formed by combining an aromatic hydrocarbon group with an alicyclic hydrocarbon group (e.g., aromatic hydrocarbon group-alicyclic hydrocarbon group-*, alicyclic hydrocarbon group-aromatic hydrocarbon group-*). * indicates a bonding site. Examples of aromatic hydrocarbon groups - alkanediyl groups -* include aralkyl groups such as benzyl and phenethyl groups. Examples of alkyl-aromatic hydrocarbon groups-* include tolyl groups, xylyl groups, and cumenyl groups. Examples of alicyclic hydrocarbon groups - alkanediyl groups -* include cyclohexylmethyl group, cyclohexylethyl group, 1-(adamantan-1-yl)methyl group, 1-(adamantan-1-yl)-1-methylethyl, and other cycloalkylalkyl groups. Examples of alkyl-alicyclic hydrocarbon groups include methylcyclohexyl group, dimethylcyclohexyl group, and cycloalkyl groups having alkyl groups such as 2-alkyladamantan-2-yl group. Examples of aromatic hydrocarbon groups - alicyclic hydrocarbon groups -* include the phenylcyclohexyl group. Examples of alicyclic hydrocarbon groups - aromatic hydrocarbon groups -* include the cyclohexylphenyl group. In addition, in the combinations, two or more types of alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and chain hydrocarbon groups may be combined. Any of the combined groups may be bonded to a benzene ring.

[0010] R 4 , R 5 , R 6 , R 7 , R 8 and R 9 In the haloalkyl group or hydrocarbon group, the -CH2- atoms may be replaced with -O-, -S-, -CO-, or -SO2-. In this case, the number of carbon atoms before replacement shall be the total number of carbon atoms in the haloalkyl group or hydrocarbon group. The number may be one or two or more. Examples of replaced groups include hydroxyl groups (groups in which the -CH2- atoms in a methyl group are replaced with -O-), thiol groups (groups in which the -CH2- atoms in a methyl group are replaced with -S-), carboxyl groups (groups in which the -CH2-CH2- atoms in an ethyl group are replaced with -O-CO-), alkoxy groups (groups in which the -CH2- atoms at any position in an alkyl group are replaced with -O-), alkoxycarbonyl groups (groups in which the -CH2-CH2- atoms at any position in an alkyl group are replaced with -O-CO-), and alkylcarbonyl groups (groups in which the -CH2- atoms at any position in an alkyl group are replaced with - Examples include groups in which CH2- is replaced by -CO-, alkylcarbonyloxy groups (groups in which -CH2-CH2- at any position within an alkyl group is replaced by -CO-O-), alkylthio groups (groups in which -CH2- at any position within an alkyl group is replaced by -S-), alkylsulfonyl groups (groups in which -CH2- at any position within an alkyl group is replaced by -SO2-), cycloalkoxy groups, cycloalkylalkoxy groups, alkoxycarbonyloxy groups, aromatic hydrocarbon group-carbonyloxy groups, etc., and groups that combine two or more of these groups. Examples of alkoxy groups include alkoxy groups having 1 to 17 carbon atoms, such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, and undecyloxy groups. The number of carbon atoms in the alkoxy group is preferably 1 to 11 or 1 to 6, more preferably 1 to 4, and even more preferably 1 to 3. Alkoxycarbonyl groups, alkylcarbonyl groups, and alkylcarbonyloxy groups represent groups in which a carbonyl group or carbonyloxy group is bonded to an alkyl group or alkoxy group as described above. Examples of alkoxycarbonyl groups include alkoxycarbonyl groups having 2 to 17 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, and butoxycarbonyl groups. Examples of alkylcarbonyl groups include alkylcarbonyl groups having 2 to 18 carbon atoms, such as acetyl, propionyl, and butyryl groups. Examples of alkylcarbonyloxy groups include alkylcarbonyloxy groups having 2 to 17 carbon atoms, such as acetyloxy, propionyloxy, and butyryloxy groups. The number of carbon atoms in the alkoxycarbonyl group is preferably 2 to 11 or 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkylcarbonyl group is preferably 2 to 18 or 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3. The number of carbon atoms in the alkylcarbonyloxy group is preferably 2 to 11 or 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3. Examples of alkylthio groups include alkylthio groups having 1 to 17 carbon atoms, such as methylthio groups, ethylthio groups, and propylthio groups. The number of carbon atoms in the alkylthio group is preferably 2 to 11, more preferably 2 to 6, and even more preferably 2 to 4. Examples of alkylsulfonyl groups include alkylsulfonyl groups having 1 to 17 carbon atoms, such as methylsulfonyl groups, ethylsulfonyl groups, and propylsulfonyl groups. The number of carbon atoms in the alkylsulfonyl group is preferably 1 to 11, more preferably 1 to 6, and even more preferably 1 to 4. Examples of cycloalkoxy groups include cycloalkoxy groups having 3 to 17 carbon atoms, such as the cyclohexyloxy group. Examples of cycloalkylalkoxy groups include cycloalkylalkoxy groups having 4 to 17 carbon atoms, such as the cyclohexylmethoxy group. Examples of alkoxycarbonyloxy groups include alkoxycarbonyloxy groups having 2 to 16 carbon atoms, such as the butoxycarbonyloxy group. Examples of aromatic hydrocarbon group-carbonyloxy groups include aromatic hydrocarbon group-carbonyloxy groups having 7 to 17 carbon atoms, such as the benzoyloxy group. Furthermore, the following groups are examples of groups in which the -CH2- contained in an alicyclic hydrocarbon group is replaced by -O- or -CO-, etc. The bonding site can be at any position. The -O- or -CO- positions of the groups shown below may also be replaced by -S- or -SO2-, respectively. TIFF0007867324000009.tif47155

[0011] X 1 It is preferable that it is an oxygen atom. X 2 It is preferable that it is an oxygen atom. X 3 It is preferable that it is an oxygen atom. X 1 The bond position is S on the benzene ring. + The position where they are bonded can be any of the or, m, or p positions. In particular, S + It is preferable that the bond is located at the p-position or m-position relative to the bonding site, and more preferably at the p-position. X 2 and X 3 The bond position is the S of the benzene ring in the fused ring. +It may be in the ortho position, meta position or para position with respect to the position where it is bonded. Among them, S + It is preferably bonded in the para position with respect to the bonding position of Since at least one of m1, m2, and m3 is 1 or more, m1 is preferably 1 or 2. m2 is preferably 0 or 1. m3 is preferably 0 or 1. m4 is preferably 0, 1, 2 or 4, and more preferably 1 or 2. m5 is preferably 0 or 1. m6 is preferably 0 or 1. Also, since 0 ≦ m1 + m7 ≦ 5, 0 ≦ m2 + m8 ≦ 4, and 0 ≦ m3 + m9 ≦ 4, m7 is preferably 0, 1 or 2, and more preferably 0 or 1. m8 is preferably 0 or 1. m9 is preferably 0 or 1. R 4 、R 5 and R 6 are each independently preferably an iodine atom, a fluorine atom, a hydroxy group, a haloalkyl group having 1 to 6 carbon atoms or an alkyl group having 1 to 6 carbon atoms (wherein -CH2- contained in the haloalkyl group and the alkyl group may be replaced by -O- or -CO-), more 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, still 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. R 7 、R 8 and R 9Each is independently preferably an iodine atom, a fluorine atom, a hydroxy group, a haloalkyl group having 1 to 6 carbon atoms or an alkyl group having 1 to 6 carbon atoms (wherein -CH2- contained in the haloalkyl group and the alkyl group may be replaced by -O- or -CO-), more 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 even more preferably an iodine atom, a fluorine atom, a trifluoromethyl group or an alkoxy group having 1 to 3 carbon atoms. R 1 、R 2 and R 3 The bonding positions of 1 、X 2 and X 3 may each be in the ortho, meta or para position with respect to the position to which 1 、X 2 and X 3 are bonded. Among them, it is preferable that they are bonded to the para or meta position with respect to the bonding positions of R 4 、R 5 、R 6 、R 7 、R 8 and R 9 The bonding positions can be arbitrarily set according to the number thereof and the like.

[0012] Examples of the cation (I) include the following cations. TIFF0007867324000010.tif234153

[0013] TIFF0007867324000011.tif248165

[0014] TIFF0007867324000012.tif113167

[0015] TIFF0007867324000013.tif116161

[0016] AI -Examples of organic anions represented by AI include sulfonic acid anions, sulfonylimide anions, sulfonylmethide anions, and carboxylic acid anions. - The organic anions represented by are preferably sulfonic acid anions, and more preferably anions represented by formula (IA). TIFF0007867324000014.tif2965[In formula (IA), Q 1 and Q 2 Each of these independently represents either 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, and the -CH2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups. Y 1 This represents a methyl group which may have substituents or an alicyclic hydrocarbon group having 3 to 24 carbon atoms which may have substituents, and the -CH2- contained in the alicyclic hydrocarbon group may be replaced with -O-, -SO2-, or -CO-.

[0017] In an anion represented by formula (IA), if a -CH2- contained in a saturated hydrocarbon group is replaced by -O- or -CO-, the number of carbon atoms before the replacement shall be considered the number of carbon atoms in the saturated hydrocarbon group. Similarly, if a -CH2- contained in an alicyclic hydrocarbon group is replaced by -O-, -SO2-, or -CO-, the number of carbon atoms before the replacement shall be considered the number of carbon atoms in the alicyclic hydrocarbon group.

[0018] Q 1 and Q 2 Examples of perfluoroalkyl groups having 1 to 6 carbon atoms include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoroisopropyl, perfluorobutyl, perfluorosec-butyl, perfluorotert-butyl, perfluoropentyl, and perfluorohexyl groups. Q 1 and Q2 Each of these is preferably independently a fluorine atom or a trifluoromethyl group, and more preferably both are fluorine atoms.

[0019] L 1 Examples of divalent saturated hydrocarbon groups in this context include linear alkanediyl groups, branched alkanediyl groups, and monocyclic or polycyclic divalent alicyclic saturated hydrocarbon groups. Groups formed by combining two or more of these groups may also be used. Specifically, linear alkane diyl groups such as methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, and heptadecane-1,17-diyl group; Branched alkanediyl groups such as ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group; Monocyclic, divalent, alicyclic saturated hydrocarbon groups such as cycloalkanediyl groups, 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.

[0020] L 1Examples of groups in which the -CH2- contained in the divalent saturated hydrocarbon group represented by is replaced with -O- or -CO- include the group represented by any of the formulas (b1-1) to (b1-3). In the groups represented by formulas (b1-1) to (b1-3) and their specific examples, the groups represented by formulas (b1-4) to (b1-11), * and ** represent the bonding site, and * is -Y 1 This represents a combination of two things.

[0021] TIFF0007867324000015.tif26118[In formula (b1-1), L b2 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms. L b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, wherein the hydrogen atoms in the saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups, and the -CH2- in the saturated hydrocarbon group may be replaced 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 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms. L b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, wherein the hydrogen atoms in the saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups, and the -CH2- in the saturated hydrocarbon group may be replaced 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 b6This represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups. L b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, wherein the hydrogen atoms in the saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups, and the -CH2- in the saturated hydrocarbon group may be replaced with -O- or -CO-. However, L b6 and L b7 The total number of carbon atoms is 23 or less.

[0022] In groups represented by formulas (b1-1) to (b1-3), if the -CH2- contained in the saturated hydrocarbon group is replaced by -O- or -CO-, the number of carbon atoms before the replacement shall be the number of carbon atoms of the saturated hydrocarbon group. As for divalent saturated hydrocarbon groups, L b1 Examples include divalent saturated hydrocarbon groups. L b2 The bond is preferably a single bond. L b3 This is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms. L b4 Preferably, this is a divalent saturated hydrocarbon group having 1 to 8 carbon atoms, and the hydrogen atoms contained in the divalent saturated hydrocarbon group may be substituted with fluorine atoms. L b5 This is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms. L b6 Preferably, it is a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms. L b7 Preferably, the saturated hydrocarbon group is a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atoms in the saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups, and the -CH2- groups in the divalent saturated hydrocarbon group may be replaced with -O- or -CO-. L 1As for the group in which the -CH2- contained in the divalent saturated hydrocarbon group represented by is replaced with -O- or -CO-, the group represented by formula (b1-1) or formula (b1-3) is preferred.

[0023] The groups represented by formula (b1-1) include those represented by formulas (b1-4) to (b1-8), respectively. TIFF0007867324000016.tif48120[In formula (b1-4), L b8 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups. In formula (b1-5), L b9 This represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the -CH2- contained in the divalent saturated hydrocarbon group may be replaced with -O- or -CO-. L b10 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and the hydrogen atoms in the divalent saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups. However, L b9 and L b10 The total number of carbon atoms is 20 or less. In formula (b1-6), L b11 This represents a divalent saturated hydrocarbon group with 1 to 21 carbon atoms. L b12 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atoms in the divalent saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups. However, L b11 and L b12 The total number of carbon atoms is 21 or less. In formula (b1-7), L b13 This represents a divalent saturated hydrocarbon group with 1 to 19 carbon atoms. L b14This represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the -CH2- contained in the divalent saturated hydrocarbon group may be replaced by -O- or -CO-. L b15 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atoms in the divalent saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups. However, L b13 ~L b15 The total number of carbon atoms is 19 or less. In formula (b1-8), L b16 This represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the -CH2- contained in the divalent saturated hydrocarbon group may be replaced with -O- or -CO-. L b17 This represents a divalent saturated hydrocarbon group with 1 to 18 carbon atoms. L b18 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the hydrogen atoms in the divalent saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups. However, L b16 ~L b18 The total number of carbon atoms is 19 or less.

[0024] L b8 This is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms. L b9 Preferably, it is a divalent saturated hydrocarbon group having 1 to 8 carbon atoms. L b10 Preferably, it is 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 Preferably, it is a divalent saturated hydrocarbon group having 1 to 8 carbon atoms. L b12 This is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms. L b13 This is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms. L b14This is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms. L b15 Preferably, it is 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 This is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms. L b17 Preferably, it is a divalent saturated hydrocarbon group having 1 to 6 carbon atoms. L b18 Preferably, it is 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.

[0025] The groups represented by formula (b1-3) include those represented by formulas (b1-9) to (b1-11), respectively. TIFF0007867324000017.tif24140 formula (b1-9), L b19 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms. L b20 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atoms in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxyl group, or an alkylcarbonyloxy group. The -CH2- in the alkylcarbonyloxy group may be replaced with -O- or -CO-, and the hydrogen atoms in the alkylcarbonyloxy group may be substituted with a hydroxyl group. However, L b19 and L b20 The total number of carbon atoms is 23 or less. In formula (b1-10), L b21 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms. L b22This represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms. L b23 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and the hydrogen atoms in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxyl group, or an alkylcarbonyloxy group. The -CH2- in the alkylcarbonyloxy group may be replaced with -O- or -CO-, and the hydrogen atoms in the alkylcarbonyloxy group may be substituted with a hydroxyl group. However, L b21 , L b22 and L b23 The total number of carbon atoms is 21 or less. In formula (b1-11), L b24 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms. L b25 This represents a divalent saturated hydrocarbon group with 1 to 21 carbon atoms. L b26 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atoms in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxyl group, or an alkylcarbonyloxy group. The -CH2- in the alkylcarbonyloxy group may be replaced with -O- or -CO-, and the hydrogen atoms in the alkylcarbonyloxy group may be substituted with a hydroxyl group. However, L b24 , L b25 and L b26 The total number of carbon atoms is 21 or less.

[0026] In the groups represented by formulas (b1-9) to (b1-11), if a hydrogen atom in a saturated hydrocarbon group is substituted with an alkylcarbonyloxy group, the number of carbon atoms before the substitution shall be considered the number of carbon atoms in the saturated hydrocarbon group.

[0027] Examples of alkylcarbonyloxy groups include acetyloxy group, propionyloxy group, butyryloxy group, cyclohexylcarbonyloxy group, and adamantylcarbonyloxy group.

[0028] The following are examples of bases represented by formula (b1-4): TIFF0007867324000018.tif17154

[0029] The following are examples of bases represented by formula (b1-5): TIFF0007867324000019.tif69148

[0030] The following are examples of bases represented by formula (b1-6): TIFF0007867324000020.tif44148

[0031] The following are examples of bases represented by formula (b1-7): TIFF0007867324000021.tif63153

[0032] The following are examples of bases represented by formula (b1-8): TIFF0007867324000022.tif24150

[0033] The following are examples of bases represented by formula (b1-2): TIFF0007867324000023.tif31161

[0034] The following are examples of bases represented by formula (b1-9): TIFF0007867324000024.tif44137

[0035] The following are examples of bases represented by formula (b1-10): TIFF0007867324000025.tif93165

[0036] The following are examples of bases represented by formula (b1-11): TIFF0007867324000026.tif85164

[0037] Y 1 Examples of alicyclic hydrocarbon groups represented by formulas (Y1) to (Y11) and (Y36) to (Y38) include those represented by formulas (Y36) to (Y38). Y 1 When the -CH2- group in the alicyclic hydrocarbon group represented by is replaced by -O-, -SO2-, or -CO-, the number of replacements may be one or two or more. Examples of such groups include those represented by formulas (Y12) to (Y35) and (Y39) to (Y43). * is L 1 This represents the bonding position with [the specified element].

[0038] TIFF0007867324000027.tif81163Y 1 The alicyclic hydrocarbon group represented is preferably a group represented by any of formulas (Y1) to (Y20), (Y26), (Y27), (Y30), (Y31), (Y39) to (Y43), more preferably a group represented by formula (Y11), (Y15), (Y16), (Y20), (Y26), (Y27), (Y30), (Y31), (Y39), (Y40), (Y42), or (Y43), and even more preferably a group represented by formula (Y11), (Y15), (Y20), (Y26), (Y27), (Y30), (Y31), (Y39), (Y40), (Y42), or (Y43). Y 1 When the alicyclic hydrocarbon group represented is a spiro ring such as formulas (Y28) to (Y35), (Y39), (Y40), (Y42), or (Y43), it is preferable that the alkanediyl group between the two oxygen atoms has one or more fluorine atoms. Furthermore, it is preferable that the methylene group adjacent to the oxygen atom among the alkanediyl groups contained in the ketal structure is not substituted with a fluorine atom.

[0039] Y 1The substituents of the methyl group represented by can be halogen atoms, hydroxyl groups, alicyclic hydrocarbon groups with 3 to 16 carbon atoms, aromatic hydrocarbon groups with 6 to 18 carbon atoms, glycidyloxy groups, and -(CH2) ja -CO-OR b1 Base 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 group combining these. ja represents an integer from 0 to 4. The -CH2- contained in the alkyl group and the alicyclic hydrocarbon group may be replaced with -O-, -SO2-, or -CO-, and the hydrogen atoms contained in the alkyl group, the alicyclic hydrocarbon group, and the aromatic hydrocarbon group may be replaced with a hydroxyl group or a fluorine atom. ) are examples. Y 1 Substituents for the alicyclic hydrocarbon group represented by include halogen atoms, hydroxyl groups, C1-C16 alkyl groups which may be substituted with hydroxyl groups (the -CH2- contained in the alkyl group may be replaced with -O- or -CO-), C3-C16 alicyclic hydrocarbon groups, C6-C18 aromatic hydrocarbon groups, C7-C21 aralkyl groups, glycidyloxy groups, and -(CH2) ja -CO-OR b1 Base 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 group combining these. ja represents an integer from 0 to 4. The -CH2- contained in the alkyl group and the alicyclic hydrocarbon group may be replaced with -O-, -SO2-, or -CO-, and the hydrogen atoms contained in the alkyl group, the alicyclic hydrocarbon group, and the aromatic hydrocarbon group may be replaced with a hydroxyl group or a fluorine atom. ) are examples.

[0040] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms. Examples of alicyclic hydrocarbon groups include cyclopentyl group, cyclohexyl group, methylcyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, norbornyl group, and adamantyl group. Alicyclic hydrocarbon groups may also have chain hydrocarbon groups, such as methylcyclohexyl group and dimethylcyclohexyl group. The number of carbon atoms in the alicyclic hydrocarbon group is preferably 3 to 12, and more preferably 3 to 10. Examples of aromatic hydrocarbon groups include phenyl groups, naphthyl groups, anthryl groups, biphenyl groups, phenanthryl groups, and other aryl groups. Aromatic hydrocarbon groups may have a chain-like hydrocarbon group or an alicyclic hydrocarbon group. Examples of aromatic hydrocarbon groups having a chain-like hydrocarbon group include tolyl groups, xylyl groups, cumenyl groups, mesityl groups, p-ethylphenyl groups, p-tert-butylphenyl groups, 2,6-diethylphenyl groups, and 2-methyl-6-ethylphenyl groups. Examples of aromatic hydrocarbon groups having an alicyclic hydrocarbon group include p-cyclohexylphenyl groups and p-adamantylphenyl groups. The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 14, and more preferably 6 to 10. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl, and dodecyl groups. The number of carbon atoms in the alkyl group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 4. Examples of alkyl groups substituted with a hydroxyl group include hydroxymethyl groups, hydroxyethyl groups, and other hydroxyalkyl groups. Examples of aralkyl groups include benzyl groups, phenethyl groups, phenylpropyl groups, naphthylmethyl groups, and naphthylethyl groups. Groups in which the -CH2- group in an alkyl group is replaced with -O-, -SO2-, or -CO- include alkoxy groups, alkylsulfonyl groups, alkoxycarbonyl groups, alkylcarbonyl groups, alkylcarbonyloxy groups, or combinations thereof. Examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy, and dodecyloxy groups. The number of carbon atoms in the alkoxy group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 4. Examples of alkylsulfonyl groups include methylsulfonyl groups, ethylsulfonyl groups, and propylsulfonyl groups. The number of carbon atoms in the alkylsulfonyl group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 4. Examples of alkoxycarbonyl groups include methoxycarbonyl groups, ethoxycarbonyl groups, and butoxycarbonyl groups. The number of carbon atoms in the alkoxycarbonyl group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 to 4. Examples of alkylcarbonyl groups include acetyl groups, propionyl groups, and butyryl groups. The number of carbon atoms in the alkylcarbonyl group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 to 4. Examples of alkylcarbonyloxy groups include acetyloxy groups, propionyloxy groups, and butyryloxy groups. The number of carbon atoms in the alkylcarbonyloxy group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 to 4. Examples of combined groups include groups combining an alkoxy group and an alkyl group, groups combining two alkoxy groups, groups combining an alkoxy group and an alkylcarbonyl group, and groups combining an alkoxy group and an alkylcarbonyloxy group. Examples of groups combining an alkoxy group and an alkyl group include alkoxyalkyl groups such as methoxymethyl, methoxyethyl, ethoxyethyl, and ethoxymethyl groups. The number of carbon atoms in the alkoxyalkyl group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 to 4. Examples of groups formed by combining alkoxy groups include alkoxyalkoxy groups such as methoxymethoxy, methoxyethoxy, ethoxymethoxy, and ethoxyethoxy. The number of carbon atoms in the alkoxyalkoxy group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 to 4. Examples of groups combining an alkoxy group and an alkylcarbonyl group include alkoxyalkylcarbonyl groups such as methoxyacetyl group, methoxypropionyl group, ethoxyacetyl group, and ethoxypropionyl group. The number of carbon atoms in the alkoxyalkylcarbonyl group is preferably 3 to 13, more preferably 3 to 7, and even more preferably 3 to 5. Examples of groups combining an alkoxy group and an alkylcarbonyloxy group include alkoxyalkylcarbonyloxy groups such as methoxyacetyloxy group, methoxypropionyloxy group, ethoxyacetyloxy group, and ethoxypropionyloxy group. The number of carbon atoms in the alkoxyalkylcarbonyloxy group is preferably 3 to 13, more preferably 3 to 7, and even more preferably 3 to 5. Groups in which the -CH2- group in an alicyclic hydrocarbon group is replaced with -O-, -SO2-, or -CO- include the groups represented by formulas (Y12) to (Y35) and (Y39) to (Y43).

[0041] Y 1 The following are some examples: TIFF0007867324000028.tif161165

[0042] Y 1Preferably, is an alicyclic hydrocarbon group having 3 to 24 carbon atoms, which may have substituents; more preferably, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, which may have substituents; even more preferably, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, which may have substituents; even more preferably, an alicyclic hydrocarbon group substituted with a hydroxyl group; and even more preferably, an adamantyl group, which may have substituents, wherein the -CH2- constituting the alicyclic hydrocarbon group or adamantyl group may be replaced with -CO-, -SO2-, or -CO-. 1 Specifically, preferably is an adamantyl group, a hydroxyadamantyl group, an oxoadamantyl group, or a group represented by formulas (Y42), (Y100) to (Y114), and particularly preferably is a hydroxyadamantyl group or an oxoadamantyl group, a group containing these, or a group represented by formulas (Y42), (Y100) to (Y114).

[0043] The anions represented by formula (IA) are preferably those represented by formulas (IA-1) to (IA-59) (hereinafter, they may be referred to as "anion (IA-1)," etc., depending on the formula number), and more preferably those represented by any of formulas (IA-1) to (IA-4), (IA-9), (IA-10), (IA-24) to (IA-33), (IA-36) to (IA-40), or (IA-47) to (IA-59).

[0044] TIFF0007867324000029.tif74141

[0045] TIFF0007867324000030.tif116155

[0046] TIFF0007867324000031.tif87144

[0047] TIFF0007867324000032.tif158157

[0048] TIFF0007867324000033.tif164160

[0049] Here R i2 ~R i7 Each of these is independently, for example, an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group. i8 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 a combination thereof, more preferably a methyl group, an ethyl group, a cyclohexyl group, or an adamantyl group. A41 This is a single bond or an alkanediyl group having 1 to 4 carbon atoms. Q 1 and Q 2 This expresses the same meaning as above. Examples of anions represented by formula (IA) include those described in Japanese Patent Publication No. 2010-204646.

[0050] Preferred anions represented by formula (IA) include those represented by formulas (Ia-1) to (Ia-38), respectively. TIFF0007867324000034.tif218153

[0051] TIFF0007867324000035.tif183165

[0052] Among these, anions represented by any of the following formulas are preferred: (Ia-1) to (Ia-3), (Ia-7) to (Ia-19), or (Ia-22) to (Ia-38).

[0053] AI - Examples of sulfonylimid anions represented by the formula include the following: TIFF0007867324000036.tif38135

[0054] AI - The following are examples of sulfonylmethide anions that can be represented: TIFF0007867324000037.tif31127

[0055] AI - Examples of carboxylic acid anions represented by the formula include the following: TIFF0007867324000038.tif48165

[0056] Examples of salt(I) include salts formed by arbitrarily combining the cations and anions mentioned above. Specific examples of salt(I) are shown in the table below. In the table below, each symbol represents the symbol attached to the structure representing the anion and cation described above, and "~" indicates that salt (I) and anion (I) correspond to each other. For example, salt (I-1) is a salt consisting of the anion represented by formula (Ia-1) and the cation represented by formula (Ic-1), salt (I-2) is a salt consisting of the anion represented by formula (Ia-2) and the cation represented by formula (Ic-1), and salt (I-55) is a salt consisting of the anion represented by formula (Ia-1) and the cation represented by formula (Ic-2). TIFF0007867324000039.tif5387 [Table 1] TIFF0007867324000041.tif41144

[0057] Among them, salt (I) Salts are preferred that combine an anion represented by any of the formulas (Ia-1) to (Ia-4), (Ia-7) to (Ia-11), (Ia-14) to (Ia-30), and (Ia-35) to (Ia-38) with a cation represented by any of the formulas (Ic-1) to (Ic-44). Specifically, salts (I-1) to (I-4), salts (I-7) to (I-11), salts (I-14) to (I-30), salts (I-35) to (I-38), salts (I-39) to (I-42), salts (I-45) to (I-49), and salts (I-52) to (I-68). , salt(I-73)~salt(I-76), salt(I-77)~salt(I-80), salt(I-83)~salt(I-87), salt(I-90)~salt(I-106), salt(I-111)~salt(I-114), salt(I-115)~salt(I-118), salt(I-121)~salt(I-125), salt(I-128)~salt(I-144), salt(I-149)~salt(I-152), salt(I-153)~salt(I-156), salt(I-159)~salt(I-163), salt(I-166)~salt(I-182), salt(I-187)~salt(I-190), salt(I-191)~salt(I-194 ), salt(I-197)~salt(I-201), salt(I-204)~salt(I-220), salt(I-225)~salt(I-228), salt(I-229)~salt(I-232), salt(I-235)~salt(I-239), salt(I-242)~salt(I-258), salt(I-263)~salt(I-266), salt(I-267)~salt(I-270), salt(I-273)~salt(I-277), salt(I-280)~salt(I-296), salt(I-301)~salt(I-304), salt(I-305)~salt(I-308), salt(I-311)~salt(I-315), salt(I-318) ~Salt (I-334), Salt (I-339)~Salt (I-342), Salt (I-343)~Salt (I-346), Salt (I-349)~Salt (I-353), Salt (I-356)~Salt (I-372), Salt (I-377)~Salt (I-380), Salt (I-381)~Salt (I-384), Salt (I-387)~Salt (I-391), Salt (I-394)~Salt (I-410), Salt (I-415)~Salt (I-418), Salt (I-419)~Salt (I-422), Salt (I-425)~Salt (I-429), Salt (I-432)~Salt (I-448), Salt (I-453)~Salt (I-456),Salt (I-457) ~ Salt (I-460), Salt (I-463) ~ Salt (I-467), Salt (I-470) ~ Salt (I-486), Salt (I-491) ~ Salt (I-494), Salt (I-495) ~ Salt (I-498), Salt (I-501) ~ Salt (I-505), Salt (I-508) ~ Salt (I-52 4) Salt (I-529) ~ Salt (I-532), Salt (I-533) ~ Salt (I-536), Salt (I-539) ~ Salt (I-543), Salt (I-546) ~ Salt (I-562), Salt (I-567) ~ Salt (I-570), Salt (I-571) ~ Salt (I-574), Salt (I-577) ~ Salt (I- 581), Salt (I-584)~Salt (I-600), Salt (I-605)~Salt (I-608), Salt (I-609)~Salt (I-612), Salt (I-615)~Salt (I-619), Salt (I-622)~Salt (I-638), Salt (I-643)~Salt (I-646), Salt (I-647)~Salt ( I-650), Salt (I-653)~Salt (I-657), Salt (I-660)~Salt (I-676), Salt (I-681)~Salt (I-684), Salt (I-685)~Salt (I-688), Salt (I-691)~Salt (I-695), Salt (I-698)~Salt (I-714), Salt (I-719)~ Salt (I-722), Salt (I-723)~Salt (I-726), Salt (I-729)~Salt (I-733), Salt (I-736)~Salt (I-752), Salt (I-757)~Salt (I-760), Salt (I-761)~Salt (I-764), Salt (I-767)~Salt (I-771), Salt (I-77 4) ~Salt (I-790), Salt (I-795) ~Salt (I-798), Salt (I-799) ~Salt (I-802), Salt (I-805) ~Salt (I-809), Salt (I-812) ~Salt (I-828), Salt (I-833) ~Salt (I-836), Salt (I-837) ~Salt (I-840), Salt (I- 843)~Salt (I-847), Salt (I-850)~Salt (I-866), Salt (I-871)~Salt (I-874), Salt (I-875)~Salt (I-878), Salt (I-881)~Salt (I-885), Salt (I-888)~Salt (I-904), Salt (I-909)~Salt (I-912), Salt ( I-913)~Salt(I-916), Salt(I-919)~Salt(I-923), Salt(I-926)~Salt(I-942), Salt(I-947)~Salt(I-950), Salt(I-951)~Salt(I-954), Salt(I-957)~Salt(I-961), Salt(I-964)~Salt(I-980),Salt (I-985) ~ Salt (I-988), Salt (I-989) ~ Salt (I-992), Salt (I-995) ~ Salt (I-999), Salt (I-1002) ~ Salt (I-1018), Salt (I-1023) ~ Salt (I-1026), Salt (I-1027) ~ Salt (I-1030), Salt (I-1033) ~ Salt (I-1037), Salt (I-1040)~Salt (I-1056), Salt (I-1061)~Salt (I-1064), Salt (I-1065)~Salt (I-1068), Salt (I-1071)~Salt (I-1075), Salt (I-1078)~Salt (I-1094), Salt (I-1099)~Salt (I- 1102), Salt (I-1103)~Salt (I-1106), Salt (I-1109)~Salt (I-1113), Salt (I-1116)~Salt (I-1132), Salt (I-1137)~Salt (I-1140), Salt (I-1141)~Salt (I-1144), Salt (I-1147)~Salt (I-1151 ), salt (I-1154)~salt (I-1170), salt (I-1175)~salt (I-1178), salt (I-1179)~salt (I-1182), salt (I-1185)~salt (I-1189), salt (I-1192)~salt (I-1208), salt (I-1213)~salt (I-1216), salt (I -1217)~Salt (I-1220), Salt (I-1223)~Salt (I-1227), Salt (I-1230)~Salt (I-1246), Salt (I-1251)~Salt (I-1254), Salt (I-1255)~Salt (I-1258), Salt (I-1261)~Salt (I-1265), Salt (I-126 8) ~Salt (I-1284), Salt (I-1289) ~Salt (I-1292), Salt (I-1293) ~Salt (I-1296), Salt (I-1299) ~Salt (I-1303), Salt (I-1306) ~Salt (I-1322), Salt (I-1327) ~Salt (I-1330), Salt (I-1331) ~Salt (I-1334), salt (I-1337)~salt (I-1341), salt (I-1344)~salt (I-1360), salt (I-1365)~salt (I-1368), salt (I-1369)~salt (I-1372), salt (I-1375)~salt (I-1379), salt (I-1382)~salt (I-1 398), salt (I-1403)~salt (I-1406), salt (I-1407)~salt (I-1410), salt (I-1413)~salt (I-1417), salt (I-1420)~salt (I-1436), salt (I-1441)~salt (I-1444), salt (I-1445)~salt (I-1448),Salt (I-1451) ~ Salt (I-1455), Salt (I-1458) ~ Salt (I-1474), Salt (I-1479) ~ Salt (I-1482), Salt (I-1483) ~ Salt (I-1486), Salt (I-1489) ~ Salt (I-1493), Salt (I-1496) ~ Salt (I-1512), Salt (I-1517) ~ Salt (I-1520), Salt (I-1521) ~ Salt (I-1524), Salt (I-1527) ~ Salt (I-1531), Salt (I-1534) ~ Salt (I-1550), Salt (I-1555) ~ Salt (I-1558), Salt (I-1559) ~ Salt (I-1 It is preferable that the salts are (562), (I-1565) to (I-1569), (I-1572) to (I-1588), (I-1593) to (I-1596), (I-1597) to (I-1600), (I-1603) to (I-1607), (I-1610) to (I-1626), (I-1631) to (I-1634), (I-1635) to (I-1638), (I-1641) to (I-1645), (I-1648) to (I-1664), and (I-1669) to (I-1672).

[0058] <Method for producing salt (I)> Salt (I) can be produced by reacting the salt represented by formula (Ia) with the salt represented by formula (Ib) in a solvent. TIFF0007867324000042.tif84161[In the formula, all signs have the same meaning as above. R A , R B and R C Each of these independently represents a hydrocarbon group having 1 to 12 carbon atoms, or R A , R B and R C They may come together to form an aromatic ring. D [This represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.] Examples of solvents include chloroform, monochlorobenzene, acetonitrile, and water. The reaction temperature is typically between 15°C and 80°C, and the reaction time is typically between 0.5 and 24 hours.

[0059] Examples of salts represented by formula (Ib) include those represented by the following formula. These salts can be easily produced by methods similar to those described in Japanese Patent Publication No. 2011-116747 and Japanese Patent Publication No. 2016-047815, or by known manufacturing methods. TIFF0007867324000043.tif198162

[0060] The salt represented by formula (Ia) can be produced by reacting the salt represented by formula (Ic) with the compound represented by formula (I-d1), the compound represented by formula (I-d2), and the compound represented by formula (I-d3) in a solvent in the presence of potassium carbonate. JPEG0007867324000044.jpg72151 [In the formula, all symbols have the same meaning as described above.] Examples of solvents include chloroform, monochlorobenzene, acetonitrile, and water. The reaction temperature is typically between 15°C and 100°C, and the reaction time is typically between 0.5 and 24 hours.

[0061] Examples of salts represented by formula (Ic) include those represented by the following formula, and they are readily available from the market. TIFF0007867324000045.tif57138

[0062] Examples of compounds represented by formula (I-d1), formula (I-d2), and formula (I-d3) include the following compounds, which are readily available from the market. TIFF0007867324000046.tif40147

[0063] The salt represented by formula (Ia) can be produced by reacting the salt represented by formula (Ie) with the compound represented by formula (I-f1), the compound represented by formula (I-f2), and the compound represented by formula (I-f3) in a solvent in the presence of a base. TIFF0007867324000047.tif75151[In this formula, all symbols have the same meaning as described above.] Examples of bases include potassium hydroxide and sodium hydride. Examples of solvents include chloroform, monochlorobenzene, acetonitrile, and water. The reaction temperature is typically between 15°C and 100°C, and the reaction time is typically between 0.5 and 24 hours.

[0064] Examples of salts represented by formula (Ie) include those represented by the following formula, and they are readily available on the market. TIFF0007867324000048.tif58150

[0065] Examples of compounds represented by formula (I-f1), formula (I-f2), and formula (I-f3) include the following compounds, which are readily available from the market. TIFF0007867324000049.tif20153

[0066] [Acid Generator] The acid generator of the present invention contains salt(I). It may contain one type of salt(I) or two or more types of salt(I). The acid generator of the present invention may contain, in addition to salt (I), an acid generator known in the resist field (hereinafter sometimes referred to as "acid generator (B)"). Acid generator (B) may be used alone or in combination of two or more types.

[0067] The acid generator (B) may be either nonionic or ionic. Examples of nonionic acid generators include sulfonate esters (e.g., 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxiimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate) and sulfones (e.g., disulfone, ketosulfone, sulfonyldiazomethane). Typical ionic acid generators include onium salts containing onium cations (e.g., diazonium salts, phosphonium salts, sulfonium salts, iodonium salts). Examples of onium salt anions include sulfonic acid anions, sulfonylimide anions, and sulfonylmethide anions.

[0068] As the acid generator (B), compounds that generate acid by radiation as described in Japanese Patent Publication Nos. 63-26653, 55-164824, 62-69263, 63-146038, 63-163452, 62-153853, 63-146029, U.S. Patent Nos. 3,779,778 and 3,849,137, German Patent No. 3914407, European Patent No. 126,712, etc., can be used. Compounds manufactured by known methods may also be used. Two or more types of acid generators (B) may be used in combination.

[0069] 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)"). TIFF0007867324000050.tif2862[In formula (B1), Q b1 and Q b2 Each of these independently represents either a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. L b1 This represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, where the -CH2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-, and the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with fluorine atoms or hydroxyl groups. Y represents a methyl group which may have substituents or an alicyclic hydrocarbon group having 3 to 24 carbon atoms which may have substituents, and the -CH2- contained in the alicyclic hydrocarbon group may be replaced with -O-, -SO2-, or -CO-. Z1 + This represents an organic cation.

[0070] Q in equation (B1) b1 Q b2 , L b1 And Y are the same as Q in equation (IA) above. 1 Q 2 , L 1 and Y 1 Similar examples can be given. Examples of sulfonic acid anions in formula (B1) include those similar to the anion represented by formula (IA).

[0071] Z1 + Examples of organic cations include organic onium cations, organic sulfonium cations, organic iodonium cations, organic ammonium cations, benzothiazolium cations, and organic phosphonium cations. Among these, organic sulfonium cations and organic iodonium cations are preferred, and aryl sulfonium cations are more preferred. Specifically, examples include cations represented by any of formulas (b2-1) to (b2-4) (hereinafter, depending on the formula number, they may be referred to as "cation (b2-1)," etc.).

[0072] In formulas (b2-1) to (b2-4) of TIFF0007867324000051.tif46167, R b4 ~R b6Each of these independently represents a chain hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms. The hydrogen atoms in the chain hydrocarbon group may be substituted with a hydroxyl group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atoms 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. The hydrogen atoms in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxyl group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkyl fluoride group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. R b4 and R b5 These atoms may bond with each other and form a ring together with the sulfur atom to which they are bonded, and the -CH2- contained in the ring may be replaced with -O-, -S-, or -CO-. R b7 and R b8 Each of these independently represents a halogen atom, a hydroxyl 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 between 0 and 5. When m2 is 2 or more, multiple R b7 They may be the same or different, and when n2 is 2 or greater, multiple R b8 They may be the same or different. R b9 and R b10 Each of these independently represents either a chain-like hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms. R b9 and R b10 These atoms may bond with each other and form a ring together with the sulfur atom to which they are bonded, and the -CH2- contained in the ring may be replaced with -O-, -S-, or -CO-. R b11 This 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. Rb12 This represents a chain hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atoms contained in the chain hydrocarbon group may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atoms 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 These may be bonded to each other and form a ring including the -CH-CO- groups to which they are bonded, and the -CH2- groups included in the ring may be replaced by -O-, -S-, or -CO-. R b13 ~R b18 Each of these independently represents a halogen atom, a hydroxyl group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, a fluorinated alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. L b31 This represents a sulfur atom or an oxygen atom. o2, p2, s2, and t2 each independently represent an integer between 0 and 5. q2 and r2 each independently represent an integer between 0 and 4. u2 represents either 0 or 1. When o2 is 2 or more, multiple R b13 They are the same or different, and when p2 is 2 or more, multiple R b14 They are the same or different, and when q2 is 2 or more, multiple R b15 They are the same or different, and when r2 is 2 or more, multiple R b16 They are the same or different, and when s2 is 2 or more, multiple R b17 They are the same or different, and when t2 is 2 or more, multiple R b18 They are either the same or different.

[0073] Aliphatic hydrocarbon groups refer to both chain-type hydrocarbon groups and alicyclic hydrocarbon groups. Examples of chain-like hydrocarbon groups 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-like hydrocarbon group preferably has 1 to 12 carbon atoms. The alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, and other cycloalkyl groups. Examples of polycyclic alicyclic hydrocarbon groups include decahydronaphthyl, adamantyl, norbornyl, and the groups listed below. TIFF0007867324000052.tif10159 In particular, R b9 ~R b12 The alicyclic hydrocarbon group preferably has 3 to 18 carbon atoms, more preferably 4 to 12 carbon atoms.

[0074] Examples of alicyclic hydrocarbon groups in which a hydrogen atom is substituted with an aliphatic hydrocarbon group include methylcyclohexyl group, dimethylcyclohexyl group, 2-methyladamantan-2-yl group, 2-ethyladamantan-2-yl group, 2-isopropyladamantan-2-yl group, methylnorbornyl group, and isobornyl group. In alicyclic hydrocarbon groups 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. A fluorinated alkyl group refers to an alkyl group having 1 to 12 carbon atoms and containing a fluorine atom, such as a fluoromethyl group, difluoromethyl group, trifluoromethyl group, and perfluorobutyl group. The number of carbon atoms in the fluorinated alkyl group is preferably 1 to 9, more preferably 1 to 6, and even more preferably 1 to 4.

[0075] Examples of aromatic hydrocarbon groups include phenyl groups, biphenyl groups, naphthyl groups, phenanthryl groups, and other aryl groups. Aromatic hydrocarbon groups may have a chain-like hydrocarbon group or an alicyclic hydrocarbon group. Examples of aromatic hydrocarbon groups with a chain-like hydrocarbon group (tolyl group, xylyl group, cumenyl group, mesityl group, p-ethylphenyl group, p-tert-butylphenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.) and aromatic hydrocarbon groups with an alicyclic hydrocarbon group (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.). Furthermore, if 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 a hydrogen atom is substituted with an alkoxy group include the p-methoxyphenyl group. Examples of chain-like hydrocarbon groups in which a hydrogen atom is substituted with an aromatic hydrocarbon group include aralkyl groups such as benzyl, phenethyl, phenylpropyl, trityl, naphthylmethyl, and naphthylethyl.

[0076] Examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy, and dodecyloxy groups. Examples of alkylcarbonyl groups include acetyl, propionyl, and butyryl groups. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms. Examples of alkylcarbonyloxy groups include methylcarbonyloxy group, ethylcarbonyloxy group, propylcarbonyloxy group, isopropylcarbonyloxy group, butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butylcarbonyloxy group, pentylcarbonyloxy group, hexylcarbonyloxy group, octylcarbonyloxy group, and 2-ethylhexylcarbonyloxy group.

[0077] R b4 and R b5 The ring formed by the bonding of these atoms together with the sulfur atoms to which they are bonded may be monocyclic, polycyclic, aromatic, non-aromatic, saturated, or unsaturated. Examples of such rings include those with 3 to 18 carbon atoms, preferably those with 4 to 18 carbon atoms. Furthermore, examples of sulfur atom-containing rings include those with 3 to 12 membered rings, preferably those with 3 to 7 membered rings, such as the rings shown below. * indicates a bonding site. TIFF0007867324000053.tif24143

[0078] R b9 and R b10 The ring formed by the combination of these elements may be monocyclic, polycyclic, aromatic, non-aromatic, saturated, or unsaturated. This ring may be a 3-membered to 12-membered ring, preferably a 3-membered to 7-membered ring. Examples include a thiolan-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxatian-4-ium ring. R b11 and R b12 The ring formed by the combination of these elements may be monocyclic, polycyclic, aromatic, non-aromatic, saturated, or unsaturated. This ring may be a 3-membered to 12-membered ring, preferably a 3-membered to 7-membered ring. Examples include oxocycloheptane rings, oxocyclohexane rings, oxonorbornane rings, and oxoadamantane rings.

[0079] Among cations (b2-1) to (b2-4), cation (b2-1) is preferred. Examples of cations (b2-1) include the following: TIFF0007867324000054.tif73149

[0080] TIFF0007867324000055.tif110165

[0081] Examples of cations (b2-2) include the following: TIFF0007867324000056.tif18150

[0082] Examples of cations (b2-3) include the following: TIFF0007867324000057.tif25122

[0083] Examples of cations (b2-4) include the following: TIFF0007867324000058.tif127165

[0084] The acid generator (B) is a combination of the anion and the organic cation described above, and these can be combined in any way. Preferably, the acid generator (B) is a combination of an anion represented by any of the formulas (Ia-1) to (Ia-3), (Ia-7) to (Ia-16), (Ia-18), (Ia-19), or (Ia-22) to (Ia-38) and a cation (b2-1), cation (b2-3), or cation (b2-4).

[0085] Preferably, the acid generator (B) is represented by formulas (B1-1) to (B1-56). Among these, those containing arylsulfonium cations 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 (B1-56) are particularly preferred. TIFF0007867324000059.tif98161

[0086] TIFF0007867324000060.tif152165

[0087] TIFF0007867324000061.tif92158

[0088] TIFF0007867324000062.tif143161

[0089] TIFF0007867324000063.tif99130

[0090] TIFF0007867324000064.tif92158

[0091] When the acid generator contains salt (I) and acid generator (B), the ratio of the content of salt (I) to 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.

[0092] [Resist composition] The resist composition of the present invention contains an acid generator containing salt (I) and a resin having an acid-unstable group (hereinafter sometimes referred to as "resin (A)"). Here, "acid-unstable group" means a group having a leaving group, in which the leaving group is removed upon contact with an acid, and the constituent unit is converted into a constituent unit having a hydrophilic group (for example, a hydroxyl group or a carboxyl group). The resist composition of the present invention preferably contains a quencher (hereinafter sometimes referred to as "quencher (C)") such as a salt that generates an acid with a lower acidity than the acid generated from the acid generator, and preferably contains a solvent (hereinafter sometimes referred to as "solvent (E)").

[0093] <Acid Generator> In the resist composition of the present invention, the total content of the acid generator is preferably 1 to 45 parts by mass, more preferably 1 to 40 parts by mass, even more preferably 3 to 40 parts by mass, even more preferably 3 to 35 parts by mass, and particularly preferably 5 to 35 parts by mass, per 100 parts by mass of the resin (A) described below.

[0094] <Resin (A)> Resin (A) has structural units having acid-unstable groups (hereinafter sometimes referred to as "structural unit (a1)"). Preferably, resin (A) further contains structural units other than structural unit (a1). Examples of structural units other than structural unit (a1) include structural units that do not have acid-unstable groups (hereinafter sometimes referred to as "structural unit (s)"), structural units other than structural unit (a1) and structural unit (s) (for example, structural units having halogen atoms as described later (hereinafter sometimes referred to as "structural unit (a4)"), structural units having non-leaved hydrocarbon groups as described later (hereinafter sometimes referred to as "structural unit (a5)"), and structural units derived from other monomers known in the art.

[0095] <Structural unit (a1)> The structural unit (a1) is derived from a monomer having an acid-unstable group (hereinafter sometimes referred to as "monomer (a1)"). The acid-unstable group contained in resin (A) is preferably the group represented by formula (1) (hereinafter also referred to as group (1)) and / or the group represented by formula (2) (hereinafter also referred to as group (2)). TIFF0007867324000065.tif2298[In formula (1), R a1 , R a2 and R a3 Each of these independently represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group combining these. a1 and R a2 These atoms bond with each other to form alicyclic hydrocarbon groups with 3 to 20 carbon atoms, along with the carbon atoms to which they are bonded. ma and na each independently represent either 0 or 1, and at least one of ma and na represents 1. * represents a bond. TIFF0007867324000066.tif2378[In formula (2), R a1’ and R a2’ Each of these independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R a3’ R represents a hydrocarbon group with 1 to 20 carbon atoms. a2’ and R a3’These atoms bond to each other, forming a heterocyclic group having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded and X. The -CH2- contained in the hydrocarbon group and the heterocyclic group may be replaced with -O- or -S-. X represents either an oxygen atom or a sulfur atom. 'na' represents either 0 or 1. * represents a bond.

[0096] R a1 , R a2 and R a3 Examples of alkyl groups in this context include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl groups. R a1 , R a2 and R a3 Examples of alkenyl groups in this context include ethenyl, propenyl, isopropenyl, butenyl, isobutenyl, tert-butenyl, pentenyl, hexenyl, heptenyl, octenyl, isooctenyl, and nonenyl groups. R a1 , R a2 and R a3 The alicyclic hydrocarbon group in this compound may be 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 a bond): R a1 , R a2 and R a3 The number of carbon atoms in the alicyclic hydrocarbon group is preferably 3 to 16. TIFF0007867324000067.tif10159R a1 , R a2 and R a3 Examples of aromatic hydrocarbon groups in this context include aryl groups such as phenyl, naphthyl, anthryl, biphenyl, and phenanthryl groups. Examples of combined groups include groups combining alkyl groups and alicyclic hydrocarbon groups (e.g., alkylcycloalkyl groups or cycloalkylalkyl groups), aralkyl groups such as benzyl groups, aromatic hydrocarbon groups having alkyl groups (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 alicyclic hydrocarbon groups (e.g., p-cyclohexylphenyl group, p-adamantylphenyl group), and aryl-cycloalkyl groups such as phenylcyclohexyl groups. Preferably, ma is 0 and na is 1. R a1 and R a2 -C(R a1 )(R a2 )(R a3 Examples of such groups include the following: Alicyclic hydrocarbon groups preferably have 3 to 12 carbon atoms. * represents a bond with -O-. TIFF0007867324000068.tif35157

[0097] R a1’ , R a2’ and R a3’ Examples of hydrocarbon groups in this context include alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these. Alkyl and alicyclic hydrocarbon groups are R a1 , R a2 and R a3 The same types of elements mentioned above can be cited. Examples of aromatic hydrocarbon groups include phenyl groups, naphthyl groups, anthryl groups, biphenyl groups, phenanthryl groups, and other aryl groups. Examples of combined groups include groups combining alkyl groups and alicyclic hydrocarbon groups (e.g., alkylcycloalkyl groups or cycloalkylalkyl groups), aralkyl groups such as benzyl groups, aromatic hydrocarbon groups having alkyl groups (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 alicyclic hydrocarbon groups (e.g., p-cyclohexylphenyl group, p-adamantylphenyl group), and aryl-cycloalkyl groups such as phenylcyclohexyl groups. R a2’ and R a3’ When they bond to each other and form a heterocyclic group with the carbon atoms to which they are bonded and X, -C(R a1’ )(R a2’ )-XR a3’ The following are examples of such groups. * indicates a bond. TIFF0007867324000069.tif18124R a1’ and R a2’ Preferably, at least one of them is a hydrogen atom. na' is preferably 0.

[0098] The following are examples of base (1): In equation (1), R a1 , R a2 and R a3 A group in which the parentheses is an alkyl group, ma=0, and na=1. A tert-butoxycarbonyl group is preferred as the group. In equation (1), R a1 , R a2 However, these combine with the carbon atoms to which they bond to form an adamantyl group, R a3 A group that is an alkyl group, with ma=0 and na=1. In equation (1), R a1 and R a2 Each of them is an alkyl group independently, and R a3 This is an adamantyl group with ma=0 and na=1. The following are examples of base (1). * indicates a bond. TIFF0007867324000070.tif170163

[0099] The following are specific examples of base (2). * represents a bond. TIFF0007867324000071.tif68162

[0100] The monomer (a1) is preferably a monomer having an acid-unstable group and an ethylenically unsaturated bond, and more preferably a (meth)acrylic monomer having an acid-unstable group.

[0101] Among (meth)acrylic monomers having acid-unstable groups, those having alicyclic hydrocarbon groups with 5 to 20 carbon atoms are preferred. If a resin (A) having structural units derived from a monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used in the resist composition, the resolution of the resist pattern can be improved.

[0102] Preferably, the structural units derived from the (meth)acrylic monomer having group (1) are the structural unit represented by formula (a1-0) (hereinafter sometimes referred to as structural unit (a1-0)), the structural unit represented by formula (a1-1) (hereinafter sometimes referred to as structural unit (a1-1)), or the structural unit represented by formula (a1-2) (hereinafter sometimes referred to as structural unit (a1-2)). More preferably, it is at least one structural unit selected from the group consisting of structural unit (a1-1) and structural unit (a1-2). These may be used individually or in combination of two or more. TIFF0007867324000072.tif46150[In formulas (a1-0), (a1-1), and (a1-2), L a01 , L a1 and L a2 These are, independently, -O- or *-O-(CH2) k1 -CO-O- represents a combination, where k1 is an integer from 1 to 7, and * represents an association with -CO-. R a01 , R a4 and R a5 Each of these independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms that may contain a halogen atom. R a02 , R a03 and R a04 Each of these independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group combining these. R a6 and R a7 Each of these independently represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by a combination of these. m1 represents an integer between 0 and 14. n1 represents an integer between 0 and 10. n1' represents an integer between 0 and 3.

[0103] R a01 , R a4 and R a5 This is preferably a hydrogen atom or a methyl group, and more preferably a methyl group. L a01 , L a1 and L a2 Preferably, an oxygen atom or *-O-(CH2) k01 It is -CO-O- (where k01 is preferably an integer from 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 groups, alkenyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and combinations thereof in formula (1) are R a1 , R a2 and R a3 Similar groups to those listed above can be cited. R a02 , R a03, and R a04 The alkyl group in is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group. R a6 and R a7 The alkyl group in is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group, an isopropyl group, or a t-butyl group, and even more preferably an ethyl group, an isopropyl group, or a t-butyl group. R a6 and R a7 The alkenyl group in is preferably an alkenyl group having 2 to 6 carbon atoms, and more preferably an ethenyl group, a propenyl group, an isopropenyl group, or a butenyl group. R a02 , R a03 , R a04 , R a6 and R a7 The number of carbon atoms in the alicyclic hydrocarbon group is preferably 5 to 12, and more preferably 5 to 10. R a02 , R a03 , R a04 , R a6 and R a7 The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 12, and more preferably 6 to 10. In groups formed by combining an alkyl group and an alicyclic hydrocarbon group, it is preferable that the total number of carbon atoms in the combined alkyl group and alicyclic hydrocarbon group is 18 or less. In groups formed by combining an alkyl group and an aromatic hydrocarbon group, it is preferable that the total number of carbon atoms in the combined alkyl group and aromatic hydrocarbon group is 18 or less. R a02 and R a03 The group is preferably an alkyl group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and more preferably a methyl group, an ethyl group, a phenyl group, or a naphthyl group. R a04 The group 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 The group is preferably an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an aromatic hydrocarbon group having 6 to 12 carbon atoms, more preferably a methyl group, an ethyl group, an isopropyl group, a t-butyl group, an ethenyl group, a phenyl group, or a naphthyl group, and even more preferably an ethyl group, an isopropyl group, a t-butyl group, an ethenyl group, or a phenyl group. m1 is preferably an integer between 0 and 3, and more preferably 0 or 1. n1 is preferably an integer between 0 and 3, and more preferably 0 or 1. n1' is preferably 0 or 1.

[0104] Examples of structural units (a1-0) include structural units represented by any of the formulas (a1-0-1) to (a1-0-18) and R in structural unit (a1-0). a01 Examples of structural units in which the corresponding methyl group is replaced by a hydrogen atom, a halogen atom, a haloalkyl group, or another alkyl group include structural units represented by any of the formulas (a1-0-1) to (a1-0-10), (a1-0-13), or (a1-0-14). TIFF0007867324000073.tif99168

[0105] Examples of structural units (a1-1) include structural units derived from monomers described in Japanese Patent Publication No. 2010-204646. In particular, structural units represented by any of formulas (a1-1-1) to (a1-1-7) and R in structural unit (a1-1) a4 A structural unit in which the corresponding methyl group is replaced by a hydrogen atom, a halogen atom, a haloalkyl group, or another alkyl group is preferred, and a structural unit represented by any of formulas (a1-1-1) to (a1-1-4) is more preferred. TIFF0007867324000074.tif38164

[0106] The structural unit (a1-2) is a structural unit represented by any of the formulas (a1-2-1) to (a1-2-14) and R in the structural unit (a1-2). a5 Examples of structural units in which the corresponding methyl group is replaced by a hydrogen atom, a halogen atom, a haloalkyl group, or another alkyl group include structural units represented by any of the formulas (a1-2-2), (a1-2-5), (a1-2-6), and (a1-2-10) to (a1-2-14). TIFF0007867324000075.tif67163

[0107] If resin (A) contains structural units (a1-0), the content is usually 5 to 60 mol%, preferably 5 to 50 mol%, and more preferably 10 to 40 mol%, relative to the total structural units of resin (A). If resin (A) contains structural unit (a1-1) and / or structural unit (a1-2), the total content of these is usually 10 to 95 mol%, preferably 15 to 90 mol%, more preferably 20 to 85 mol%, even more preferably 25 to 75 mol%, and even more preferably 30 to 75 mol%, relative to the total structural units of resin (A).

[0108] Examples of structural units having a base (2) in structural unit (a1) include the structural unit represented by formula (a1-4) (hereinafter sometimes referred to as "structural unit (a1-4)"). TIFF0007867324000076.tif3854[In formula (a1-4), R a32 This represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms that may contain a halogen atom. R a33 This represents a halogen atom, a hydroxyl group, a C1-C6 alkyl group, a C1-C6 alkoxy group, a C2-C12 alkoxyalkyl group, a C2-C12 alkoxyalkoxy group, a C2-C4 alkylcarbonyl group, a C2-C4 alkylcarbonyloxy group, an acryloyloxy group, or a methacryloyloxy group. A a30 is a single bond or* -X a31 -( A a32 -X a32 ) nc - represents -R a32 This represents the bonding site with the carbon atom to which it is bonded. A a32 This represents an alkanediyl group with 1 to 6 carbon atoms. X a31 and X a32 These represent -O-, -CO-O-, or -O-CO- independently. nc represents 0 or 1. la represents an integer between 0 and 4. If la is 2 or greater, multiple R a33 They may be identical or different from one another. R a34 and R a35 Each of these independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R a36 R represents a hydrocarbon group with 1 to 20 carbon atoms. a35 and R a36 These atoms bond with each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms, and the -CH2- contained in this hydrocarbon group and the divalent hydrocarbon group may be replaced with -O- or -S-.

[0109] R a32 and R a33 Examples of halogen atoms in this context include fluorine atoms, chlorine atoms, and bromine atoms. R a32 Examples of C1-C6 alkyl groups that may have halogen atoms include trifluoromethyl, difluoromethyl, methyl, perfluoroethyl, 2,2,2-trifluoroethyl, 1,1,2,2-tetrafluoroethyl, ethyl, perfluoropropyl, 2,2,3,3,3-pentafluoropropyl, propyl, perfluorobutyl, 1,1,2,2,3,3,4,4-octafluorobutyl, butyl, perfluoropentyl, 2,2,3,3,4,4,5,5,5-nonafluoropentyl, pentyl, hexyl, and perfluorohexyl groups. Ra32 The hydrogen atom or an alkyl group having 1 to 4 carbon atoms is preferred, a hydrogen atom, a methyl group, or an ethyl group is more preferred, and a hydrogen atom or a methyl group is even more preferred. R a33 Examples of alkyl groups in this context include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, and hexyl groups. R a33 Examples of alkoxy groups in this compound include methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, tert-butoxy, pentyloxy, and hexyloxy groups. The alkoxy group is preferably a carbon-1 to carbon-4 alkoxy group, more preferably a methoxy or ethoxy group, and even more preferably a methoxy group. R a33 Examples of alkoxyalkyl groups in this context include methoxymethyl, ethoxyethyl, propoxymethyl, isopropoxymethyl, butoxymethyl, sec-butoxymethyl, and tert-butoxymethyl groups. The alkoxyalkyl group is preferably a carbon-2 to carbon-8 alkoxyalkyl group, more preferably a methoxymethyl or ethoxyethyl group, and even more preferably a methoxymethyl group. R a33 Examples of alkoxyalkoxy groups in this context include methoxymethoxy, methoxyethoxy, ethoxymethoxy, ethoxyethoxy, propoxymethoxy, isopropoxymethoxy, butoxymethoxy, sec-butoxymethoxy, and tert-butoxymethoxy. The alkoxyalkoxy group is preferably one having 2 to 8 carbon atoms, and more preferably a methoxyethyl or ethoxyethyl group. R a33 Examples of alkylcarbonyl groups in this compound include acetyl, propionyl, and butyryl groups. The alkylcarbonyl group is preferably one having 2 to 3 carbon atoms, with acetyl being more preferred. R a33Examples of alkylcarbonyloxy groups in this context include acetyloxy groups, propionyloxy groups, and butyryloxy groups. The alkylcarbonyloxy group is preferably an alkylcarbonyloxy group having 2 to 3 carbon atoms, and more preferably an acetyloxy group. R a33 The group is preferably a halogen atom, a hydroxyl group, a C1-C4 alkyl group, a C1-C4 alkoxy group, or a C2-C8 alkoxyalkoxy group; more preferably a fluorine atom, an iodine atom, a hydroxyl group, a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group, or an ethoxymethoxy group; and even more preferably a fluorine atom, an iodine atom, a hydroxyl group, a methyl group, a methoxy group, or an ethoxyethoxy group.

[0110] *-X a31 -( A a32 -X a32 ) nc - for example, *-O-, *-CO-O-, *-O-CO-, *-CO-OA a32 -CO-O-, *-O-CO-A a32 -O-, *-OA a32 -CO-O-, *-CO-OA a32 -O-CO-, *-O-CO-A a32 -O-CO- is one example. In particular, *-CO-O- and *-CO-OA are good examples. a32 -CO-O- or *-OA a32 -CO-O- is preferred.

[0111] Examples of alkanediyl groups include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group. A a32 It is preferable that this is a methylene group or an ethylene group.

[0112] A a30These are single bonds, *-CO-O- or *-CO-OA a32 It is preferably -CO-O-, more preferably a single bond, *-CO-O- or *-CO-O-CH2-CO-O-, and even more preferably a single bond or *-CO-O-.

[0113] la is preferably 0, 1, or 2, more preferably 0 or 1, and even more preferably 0. R a34 , R a35 and R a36 Examples of hydrocarbon groups in this context include alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and groups that combine these. Examples of alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl groups. Alicyclic hydrocarbon groups may be monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of polycyclic alicyclic hydrocarbon groups include decahydronaphthyl, adamantyl, norbornyl, and the following groups (* indicates a bonding site). Examples of aromatic hydrocarbon groups include phenyl groups, naphthyl groups, anthryl groups, biphenyl groups, phenanthryl groups, and other aryl groups. Examples of combined groups include groups combining alkyl groups and alicyclic hydrocarbon groups (e.g., cycloalkylalkyl groups), aralkyl groups such as benzyl groups, aromatic hydrocarbon groups having alkyl groups (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 alicyclic hydrocarbon groups (e.g., p-cyclohexylphenyl group, p-adamantylphenyl group), and aryl-cycloalkyl groups such as phenylcyclohexyl groups. In particular, R a36Examples include alkyl groups having 1 to 18 carbon atoms, alicyclic hydrocarbon groups having 3 to 18 carbon atoms, aromatic hydrocarbon groups having 6 to 18 carbon atoms, or groups formed by combining these.

[0114] R a34 Preferably, it is a hydrogen atom. R a35 Preferably, this is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a methyl group or an ethyl group. R a36 The hydrocarbon group 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 a combination thereof, 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 the alicyclic hydrocarbon group in are preferably unsubstituted. a36 In this context, the aromatic hydrocarbon group is preferably an aromatic ring having an aryloxy group with 6 to 10 carbon atoms.

[0115] -OC(R) in structural units (a1-4) a34 )(R a35 )-OR a36 It is eliminated upon contact with an acid (e.g., p-toluenesulfonic acid) to form a hydroxyl group. -OC(R a34 )(R a35 )-OR a36 It is preferable that the atom is bonded to the ortho- or para-position of the benzene ring, and more preferably to the para-position.

[0116] Examples of structural units (a1-4) include monomer-derived structural units described in Japanese Patent Publication No. 2010-204646. Preferably, structural units represented by formulas (a1-4-1) to (a1-4-18) and R in structural unit (a1-4) are used. a32Examples of structural units in which the hydrogen atom corresponding to is replaced by a halogen atom, a haloalkyl group, or an alkyl group include, more preferably, the structural units represented by formulas (a1-4-1) to (a1-4-5), (a1-4-10), (a1-4-13), and (a1-4-14), respectively. TIFF0007867324000078.tif99165

[0117] If resin (A) has structural units (a1-4), the content of these units 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%, relative to the total amount of all structural units of resin (A).

[0118] Structural units derived from (meth)acrylic monomers having group (2) include the structural unit represented by formula (a1-5) (hereinafter sometimes referred to as "structural unit (a1-5)"). TIFF0007867324000079.tif4253 formula (a1-5), R a8 This represents an alkyl group having 1 to 6 carbon atoms, which may contain a halogen atom, a hydrogen atom, or a halogen atom. Z a1 This is a single bond or *-(CH2) h3 -CO-L 54 - represents, h3 represents an integer from 1 to 4, and * represents L 51 This represents a combination of two things. L 51 , L 52 , L 53 and L 54 These represent either -O- or -S- independently. s1 represents an integer between 1 and 3. s1' represents an integer between 0 and 3.

[0119] Examples of halogen atoms include fluorine atoms and chlorine atoms, with fluorine atoms being preferred. Examples of C1-C6 alkyl groups that may contain halogen atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, fluoromethyl, and trifluoromethyl groups. In equation (a1-5), R a8 The preferred element is a hydrogen atom, a methyl group, or a trifluoromethyl group. L 51 An oxygen atom is preferred. L 52 and L 53 Preferably, one of them is -O- and the other is -S-. s1 is preferably 1. s1' is preferably an integer between 0 and 2. Z a1 A single bond or *-CH2-CO-O- is preferred.

[0120] Examples of structural units (a1-5) include monomer-derived structural units described in Japanese Patent Publication No. 2010-61117. Among these, structural units represented by formulas (a1-5-1) to (a1-5-4) are preferred, and structural units represented by formula (a1-5-1) or (a1-5-2) are more preferred. TIFF0007867324000080.tif31129

[0121] If resin (A) has structural units (a1-5), the content of these units 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%, relative to the total structural units of resin (A).

[0122] In addition, the following structural units (a1) can also be listed. TIFF0007867324000081.tif27161

[0123] If resin (A) contains structural units such as (a1-3-1) to (a1-3-7) above, the content of these structural units 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% relative to the total structural units of resin (A).

[0124] <Structural unit (s)> Structural units (s) are derived from monomers that do not have acid-unstable groups (hereinafter sometimes referred to as "monomers (s)"). Monomers that do not have acid-unstable groups and are known in the field of photoresists can be used to derive structural units (s). The structural unit (s) preferably has a hydroxyl group or a lactone ring. If a resin having a structural unit having a hydroxyl group and no acid-unstable group (hereinafter sometimes referred to as "structural unit (a2)") and / or a structural unit having a lactone ring and no acid-unstable group (hereinafter sometimes referred to as "structural unit (a3)") is used in the resist composition of the present invention, the resolution of the resist pattern and the adhesion to the substrate can be improved.

[0125] <Structural Unit (a2)> The hydroxyl group in structural unit (a2) may be either an alcoholic hydroxyl group or a phenolic hydroxyl group. When manufacturing a resist pattern from the resist composition of the present invention, if a high-energy beam such as a KrF excimer laser (248 nm), electron beam, or EUV (ultra-ultraviolet light) is used as the exposure light source, a structural unit (a2) having a phenolic hydroxyl group is preferred, and it is more preferable to use the structural unit (a2-A) described later. Furthermore, if an ArF excimer laser (193 nm) or the like is used, a structural unit (a2) having an alcoholic hydroxyl group is preferred, and it is more preferable to use the structural unit (a2-1) described later. The structural unit (a2) may consist of one type alone, or it may consist of two or more types.

[0126] A structural unit having a phenolic hydroxyl group in structural unit (a2) is the structural unit represented by formula (a2-A) (hereinafter sometimes referred to as "structural unit (a2-A)"). TIFF0007867324000082.tif4248[In formula (a2-A), R a50 This represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms that may contain a halogen atom. R a51 This represents a halogen atom, a hydroxyl group, a C1-C6 alkyl group, a C1-C6 alkoxy group, a C2-C12 alkoxyalkyl group, a C2-C12 alkoxyalkoxy group, a C2-C4 alkylcarbonyl group, a C2-C4 alkylcarbonyloxy group, an acryloyloxy group, or a methacryloyloxy group. A a50 This is a single bond or *-X a51 -( A a52 -X a52 ) nb - represents -R a50 This represents the bonding relationship between the carbon atom and the bonded carbon atom. A a52 This represents an alkanediyl group with 1 to 6 carbon atoms. X a51 and X a52 These represent -O-, -CO-O-, or -O-CO- independently. nb represents either 0 or 1. mb represents an integer between 0 and 4. If mb is an integer greater than or equal to 2, multiple R a51 They may be identical or different from one another.

[0127] R a50 and R a51 Examples of halogen atoms in this context include fluorine atoms, chlorine atoms, and bromine atoms. R a50Examples of C1-C6 alkyl groups that may have halogen atoms include trifluoromethyl, difluoromethyl, methyl, perfluoroethyl, 2,2,2-trifluoroethyl, 1,1,2,2-tetrafluoroethyl, ethyl, perfluoropropyl, 2,2,3,3,3-pentafluoropropyl, propyl, perfluorobutyl, 1,1,2,2,3,3,4,4-octafluorobutyl, butyl, perfluoropentyl, 2,2,3,3,4,4,5,5,5-nonafluoropentyl, pentyl, hexyl, and perfluorohexyl groups. R a50 The hydrogen atom or an alkyl group having 1 to 4 carbon atoms is preferred, a hydrogen atom, a methyl group, or an ethyl group is more preferred, and a hydrogen atom or a methyl group is even more preferred. R a51 Examples of alkyl groups in this context include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, and hexyl groups. The alkyl group is preferably a C1-C4 alkyl group, more preferably a methyl or ethyl group, and even more preferably a methyl group. R a51 Examples of alkoxy groups in this compound include methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, and tert-butoxy groups. The alkoxy group is preferably a carbon-1 to carbon-4 alkoxy group, more preferably a methoxy or ethoxy group, and even more preferably a methoxy group. R a51 Examples of alkoxyalkyl groups in this context include methoxymethyl, ethoxyethyl, propoxymethyl, isopropoxymethyl, butoxymethyl, sec-butoxymethyl, and tert-butoxymethyl groups. The alkoxyalkyl group is preferably a carbon-2 to carbon-8 alkoxyalkyl group, more preferably a methoxymethyl or ethoxyethyl group, and even more preferably a methoxymethyl group. R a51Examples of alkoxyalkoxy groups in this context include methoxymethoxy, methoxyethoxy, ethoxymethoxy, ethoxyethoxy, propoxymethoxy, isopropoxymethoxy, butoxymethoxy, sec-butoxymethoxy, and tert-butoxymethoxy. The alkoxyalkoxy group is preferably one having 2 to 8 carbon atoms, with methoxyethoxy or ethoxyethoxy being more preferred. R a51 Examples of alkylcarbonyl groups in this compound include acetyl, propionyl, and butyryl groups. The alkylcarbonyl group is preferably one having 2 to 3 carbon atoms, with acetyl being more preferred. R a51 Examples of alkylcarbonyloxy groups in this context include acetyloxy groups, propionyloxy groups, and butyryloxy groups. The alkylcarbonyloxy group is preferably an alkylcarbonyloxy group having 2 to 3 carbon atoms, and more preferably an acetyloxy group. R a51 The group is preferably a halogen atom, a hydroxyl group, a C1-C4 alkyl group, a C1-C4 alkoxy group, or a C2-C8 alkoxyalkoxy group; more preferably a fluorine atom, an iodine atom, a hydroxyl group, a methyl group, a methoxy group, an ethoxy group, an ethoxyethoxy group, or an ethoxymethoxy group; and even more preferably a fluorine atom, an iodine atom, a hydroxyl group, a methyl group, a methoxy group, or an ethoxyethoxy group.

[0128] *-X a51 -( A a52 -X a52 ) nb - for example, *-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- is one example. In particular, *-CO-O- and *-CO-OA are good examples. a52 -CO-O- or *-OA a52-CO-O- is preferred.

[0129] Examples of alkanediyl groups include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group. A a52 It is preferable that this is a methylene group or an ethylene group.

[0130] A a50 These are single bonds, *-CO-O- or *-CO-OA a52 It is preferably -CO-O-, more preferably a single bond, *-CO-O- or *-CO-O-CH2-CO-O-, and even more preferably a single bond or *-CO-O-.

[0131] mb is preferably 0, 1, or 2, more preferably 0 or 1, and particularly preferably 0. The hydroxyl group is preferably bonded to the ortho or para position of the benzene ring, and more preferably to the para position.

[0132] Examples of structural units (a2-A) include monomer-derived structural units described in Japanese Patent Publication No. 2010-204634 and Japanese Patent Publication No. 2012-12577. As for the structural unit (a2-A), the structural unit represented by formulas (a2-2-1) to (a2-2-16) and the R in the structural unit (a2-A) in the structural unit (a2-A) represented by formulas (a2-2-1) to (a2-2-16) are a50Examples of structural units in which the methyl group corresponding to is replaced by a hydrogen atom, a halogen atom, a haloalkyl group, or another alkyl group. Structural unit (a2-A) is a structural unit represented by formula (a2-2-1), formula (a2-2-3), formula (a2-2-6), formula (a2-2-8), formula (a2-2-12) to formula (a2-2-14), and in structural units represented by formula (a2-2-1), formula (a2-2-3), formula (a2-2-6), formula (a2-2-8), and formula (a2-2-12) to formula (a2-2-14), the R in structural unit (a2-A) is a50 Preferably, the structural unit is one in which the corresponding methyl group is replaced by a hydrogen atom, and in the structural unit represented by formula (a2-2-3), the structural unit represented by formula (a2-2-8), the structural unit represented by formulas (a2-2-12) to (a2-2-14), and the structural unit represented by formula (a2-2-3) or the structural unit represented by formula (a2-2-8), and the structural unit represented by formulas (a2-2-12) to (a2-2-14), the R in structural unit (a2-A) a50 It is more preferable that the methyl group corresponding to is replaced by a hydrogen atom in the structural unit represented by formula (a2-2-8) and the structural unit represented by formula (a2-2-8), in the structural unit (a2-A) R a50 It is even more preferable that the corresponding methyl group is replaced by a hydrogen atom in the structural unit. TIFF0007867324000083.tif64168

[0133] When the resin (A) contains structural units (a2-A), the content of structural units (a2-A) is preferably 5 to 80 mol%, more preferably 10 to 70 mol%, even more preferably 15 to 65 mol%, and even more preferably 20 to 65 mol%, relative to the total number of structural units. The structural unit (a2-A) can be incorporated into resin (A) by polymerizing using structural unit (a1-4), for example, and then treating with an acid such as p-toluenesulfonic acid. Alternatively, the structural unit (a2-A) can be incorporated into resin (A) by polymerizing using acetoxystyrene, for example, and then treating with an alkali such as tetramethylammonium hydroxide.

[0134] A structural unit having an alcoholic hydroxyl group in structural unit (a2) is the structural unit represented by formula (a2-1) (hereinafter sometimes referred to as "structural unit (a2-1)"). TIFF0007867324000084.tif4156 formula (a2-1), L a3 is -O- or *-O-(CH2) k2 -CO-O- represents, k2 represents an integer between 1 and 7. * represents a combination with -CO-. R a14 represents a hydrogen atom or a methyl group. R a15 and R a16 Each of these independently represents a hydrogen atom, a methyl group, or a hydroxyl group. o1 represents an integer between 0 and 10.

[0135] In equation (a2-1), L a3 Preferably, -O-, -O-(CH2) f1 The result is -CO-O- (where f1 represents any integer from 1 to 4), and more preferably -O-. R a14 The group is preferably a methyl group. R a15 Preferably, it is a hydrogen atom. R a16 This is preferably a hydrogen atom or a hydroxyl group. o1 is preferably an integer between 0 and 3, more preferably 0 or 1.

[0136] Examples of structural units (a2-1) include structural units derived from monomers described in Japanese Patent Publication No. 2010-204646. Structural units represented by any of formulas (a2-1-1) to (a2-1-6) are preferred, structural units represented by any of formulas (a2-1-1) to (a2-1-4) are more preferred, and structural units represented by formula (a2-1-1) or (a2-1-3) are even more preferred. TIFF0007867324000085.tif53150

[0137] If resin (A) contains structural unit (a2-1), its content is typically 1 to 45 mol%, preferably 1 to 40 mol%, more preferably 1 to 35 mol%, even more preferably 1 to 20 mol%, and even more preferably 1 to 10 mol%, relative to the total structural units of resin (A).

[0138] <Structural unit (a3)> The lactone ring of the structural unit (a3) ​​may be a monocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ring, or a δ-valerolactone ring, or it may be a fused ring of a monocyclic lactone ring and another ring. Preferably, it may be a γ-butyrolactone ring, an adamantane lactone ring, or a bridging ring containing a γ-butyrolactone ring structure (for example, a structural unit represented by the following formula (a3-2)).

[0139] 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 included alone, or two or more may be included. TIFF0007867324000086.tif51164[In formulas (a3-1), (a3-2), (a3-3), and (a3-4), L a4 , L a5 and L a6 These are, independently, -O- or *-O-(CH2) k3 This represents a base represented by -CO-O-(where k3 is an integer from 1 to 7). L a7 is -O-, *-OLa8 -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 of these independently represents an alkanediyl group with 1 to 6 carbon atoms. * indicates a bonding site with a carbonyl group. R a18 , R a19 and R a20 Each of these independently represents either a hydrogen atom or a methyl group. R a24 This represents an alkyl group having 1 to 6 carbon atoms, which may contain a halogen atom, a hydrogen atom, or a halogen atom. X a3 represents -CH2- or an oxygen atom. R a21 This represents an aliphatic hydrocarbon group with 1 to 4 carbon atoms. R a22 , R a23 and R a25 Each of these independently represents a carboxyl group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. p1 represents an integer between 0 and 5. q1 represents an integer between 0 and 3. r1 represents an integer between 0 and 3. w1 represents an integer between 0 and 8. When p1, q1, r1 and / or w1 are 2 or more, multiple R a21 , R a22 , R a23 and / or R a25 They may be the same as each other, or they may be different.

[0140] R a21 , R a22 , R a23 and R a25Examples of aliphatic hydrocarbon groups in this context include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, and tert-butyl groups. R a24 Examples of halogen atoms in this context include fluorine, chlorine, bromine, and iodine atoms. R a24 Examples of alkyl groups in this context include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, and hexyl groups, with alkyl groups having 1 to 4 carbon atoms being preferred, and methyl or ethyl groups being more preferred. R a24 Examples of alkyl groups having halogen atoms in this context include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoroisopropyl, perfluorobutyl, perfluorosec-butyl, perfluorotert-butyl, perfluoropentyl, perfluorohexyl, trichloromethyl, tribromomethyl, and triiodomethyl groups. L a8 and L a9 Examples of alkanediyl groups in this compound include methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, butane-1,3-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl, pentane-1,4-diyl, and 2-methylbutane-1,4-diyl.

[0141] In equations (a3-1) to (a3-3), L a4 ~L a6 These are each independently, preferably -O- or *-O-(CH2) k3 In -CO-O-, k3 is an integer from 1 to 4, more preferably -O- and *-O-CH2-CO-O-, and even more preferably an oxygen atom. R a18 ~R a21 The group is preferably a methyl group. R a22 and R a23 Each of these is independently preferably a carboxyl group, a cyano group, or a methyl group. p1, q1, and r1 are each independently, preferably integers from 0 to 2, and more preferably 0 or 1.

[0142] In equation (a3-4), R a24 Preferably, it is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group, or an ethyl group, and even more preferably a hydrogen atom or a methyl group. R a25 The group is preferably a carboxyl group, a cyano group, or a methyl group. L a7 Preferably -O- or *-OL a8 It is -CO-O-, and more preferably -O-, -O-CH2-CO-O-, or -O-C2H4-CO-O-. w1 is preferably an integer between 0 and 2, and more preferably 0 or 1. In particular, formula (a3-4)' is preferred over formula (a3-4). TIFF0007867324000087.tif4051 (in the formula, R a24 , L a7 (This expresses the same meaning as above.)

[0143] Examples of structural units (a3) ​​include those derived from monomers described in Japanese Patent Publication No. 2010-204646, Japanese Patent Publication No. 2000-122294, and Japanese Patent Publication No. 2012-41274. Examples of structural units (a3) ​​include those represented by any of the 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 said structural units, R in formulas (a3-1) to (a3-4). a18 , R a19 , R a20 and R a24A structural unit in which the corresponding methyl group is replaced by a hydrogen atom is preferred.

[0144] TIFF0007867324000088.tif118165

[0145] When resin (A) contains structural units (a3), the total content is usually 5 to 70 mol%, preferably 10 to 65 mol%, and more preferably 10 to 60 mol%, relative to the total structural units of resin (A). Furthermore, the content of structural unit (a3-1), structural unit (a3-2), structural unit (a3-3), or structural unit (a3-4) is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, and even more preferably 10 to 50 mol%, relative to the total structural units of resin (A).

[0146] <Structural Unit (a4)> The following are examples of structural units (a4): TIFF0007867324000089.tif3066[In formula (a4), R 41 represents a hydrogen atom or a methyl group. R 42 This represents a saturated hydrocarbon group having 1 to 24 fluorine atoms, and the -CH2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-. R 42 Saturated hydrocarbon groups represented by include chain hydrocarbon groups, monocyclic or polycyclic alicyclic hydrocarbon groups, and groups formed by combining these.

[0147] Examples of chain-like hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl groups. Examples of monocyclic or polycyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups; and polycyclic alicyclic hydrocarbon groups such as decahydronaphthyl, adamantyl, norbornyl, and the following groups (* indicates a bond). TIFF0007867324000090.tif11159 Examples of groups formed by combinations 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.

[0148] Examples of structural units (a4) include structural units represented by at least one selected from the group consisting of formulas (a4-0), (a4-1), (a4-2), (a4-3), and (a4-4). TIFF0007867324000091.tif4652[In formula (a4-0), R 5 represents a hydrogen atom or a methyl group. L 4a This represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms. L 3a This represents a perfluoroalkanediyl group having 1 to 8 carbon atoms or a perfluorocycloalkanediyl group having 3 to 12 carbon atoms. R 6 This represents a hydrogen atom or a fluorine atom.

[0149] L 4aExamples of divalent aliphatic saturated hydrocarbon groups in this context include linear alkanediyl groups such as methylene, ethylene, propane-1,3-diyl, and butane-1,4-diyl, and branched alkanediyl groups such as ethane-1,1-diyl, propane-1,2-diyl, butane-1,3-diyl, 2-methylpropane-1,3-diyl, and 2-methylpropane-1,2-diyl. L 3a The perfluoroalkanediyl groups in this product include difluoromethylene, perfluoroethylene, perfluoropropane-1,1-diyl, perfluoropropane-1,3-diyl, perfluoropropane-1,2-diyl, perfluoropropane-2,2-diyl, perfluorobutane-1,4-diyl, perfluorobutane-2,2-diyl, perfluorobutane-1,2-diyl, perfluoropentane-1,5-diyl, perfluoropentane-2,2-diyl, and perfluoropentane-3 Examples include 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 perfluorocycloalkanediyl groups in this context include perfluorocyclohexanediyl group, perfluorocyclopentanediyl group, perfluorocycloheptanediyl group, and perfluoroadamantanediyl group.

[0150] L 4a Preferably, it is a single bond, a methylene group, or an ethylene group, and more preferably a single bond and a methylene group. L 3a The group is preferably a perfluoroalkanediyl group having 1 to 6 carbon atoms, and more preferably a perfluoroalkanediyl group having 1 to 3 carbon atoms.

[0151] The structural units (a4-0) are the structural units shown below and the R in the structural units (a4-0) within the structural units below. 5 One example is a structural unit in which the corresponding methyl group is replaced by a hydrogen atom. TIFF0007867324000092.tif98165

[0152] TIFF0007867324000093.tif4466[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 substituents, and the -CH2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-. A a41 This represents an alkanediyl group having 1 to 6 carbon atoms, which may have substituents, or a group represented by formula (a-g1). However, A a41 and R a42 At least one of these atoms has a halogen atom (preferably a fluorine atom) as a substituent. TIFF0007867324000094.tif1384 [In formula (a-g1), s represents either 0 or 1. A a42 and A a44 Each of these independently represents a divalent saturated hydrocarbon group having 1 to 5 carbon atoms, which may have substituents. A a43 This represents a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, which may have single bonds or substituents. X a41 and X a42 These represent -O-, -CO-, -CO-O-, or -O-CO-, respectively, independently. However, A a42 , A a43 , A a44 , X a41 and X a42 The total number of carbon atoms is 7 or less. * represents a bond, and the * on the right is -O-CO-Ra42 This is a combination of [two characters].

[0153] R a42 Examples of saturated hydrocarbon groups in this context include chain-type saturated hydrocarbon groups, monocyclic or polycyclic alicyclic saturated hydrocarbon groups, and groups formed by combining these. Examples of chain-type saturated hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl groups. Examples of monocyclic or polycyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups; and polycyclic alicyclic saturated hydrocarbon groups such as decahydronaphthyl, adamantyl, norbornyl, and the following groups (* indicates a bond). TIFF0007867324000095.tif11159 Examples of groups formed by combinations 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.

[0154] R a42 The substituents that may be present include at least one selected from halogen atoms and groups represented by formula (a-g3). Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with fluorine atoms being preferred. TIFF0007867324000096.tif965[In formula (a-g3), X a43 * represents an oxygen atom, a carbonyl group, *-O-CO-, or *-CO-O-. A a45 * represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms, which may contain a halogen atom. a42 This represents a combination of two elements. However, Ra42 -X a43 -A a45 In R a42 If it does not have a halogen atom, then A a45 This represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms and containing at least one halogen atom.

[0155] A a45 Aliphatic hydrocarbon groups in this context include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl; Examples include 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 bond). TIFF0007867324000097.tif11159 Examples of groups formed by combinations 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.

[0156] R a42 The aliphatic hydrocarbon group may have a halogen atom, and the aliphatic hydrocarbon group having an alkyl group with a halogen atom and / or a group represented by formula (a-g3) is more preferred. R a42When is an aliphatic hydrocarbon group having a halogen atom, it is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, even 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 perfluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorohexyl group, perfluoroheptyl group, and perfluorooctyl group. Examples of perfluorocycloalkyl groups include perfluorocyclohexyl group. R a42 However, if it is an aliphatic hydrocarbon group having a group represented by formula (a-g3), then R is calculated including the number of carbon atoms in the group represented by formula (a-g3). a42 The total number of carbon atoms is preferably 15 or less, and more preferably 12 or less. If the atom has a substituent represented by formula (a-g3), the number of substituents is preferably one.

[0157] R a42 If R is an aliphatic hydrocarbon having a group represented by formula (a-g3), a42 More preferably, the group is represented by formula (a-g2). TIFF0007867324000098.tif879[In formula (a-g2), A a46 This represents a divalent aliphatic hydrocarbon group having 1 to 17 carbon atoms, which may contain a halogen atom. X a44 This represents **-O-CO- or **-CO-O- (where ** is A a46 (Represents a combination with) A a47 This represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms, which may contain a halogen atom. However, A a46 , A a47 and X a44 The total number of carbon atoms is 18 or less, A a46 and A a47 At least one of them has at least one halogen atom. * indicates a bond with a carbonyl group.

[0158] A a46 The aliphatic hydrocarbon group preferably has 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. A a47 The number of carbon atoms in the aliphatic hydrocarbon group is preferably 4 to 15, more preferably 5 to 12, A a47 A cyclohexyl group or an adamantyl group is more preferable.

[0159] The preferred structure of the group represented by formula (a-g2) is as follows (* indicates a bond with a carbonyl group). TIFF0007867324000099.tif13161

[0160] A a41 Examples of alkanediyl groups in this context include linear alkanediyl groups such as methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, and hexane-1,6-diyl group; and branched alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,2-diyl group, 1-methylbutane-1,4-diyl group, and 2-methylbutane-1,4-diyl group. A a41 Examples of substituents on the alkanediyl group include hydroxyl groups and alkoxy groups having 1 to 6 carbon atoms. A a41 The group 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.

[0161] A in the group represented by formula (a-g1) a42 , A a43 and A a44Examples of divalent saturated hydrocarbon groups represented by include linear or branched alkanediyl groups and monocyclic divalent alicyclic hydrocarbon groups, as well as groups formed by combining alkanediyl groups and divalent alicyclic hydrocarbon groups. Specifically, examples include methylene groups, ethylene groups, propane-1,3-diyl groups, propane-1,2-diyl groups, butane-1,4-diyl groups, 1-methylpropane-1,3-diyl groups, 2-methylpropane-1,3-diyl groups, and 2-methylpropane-1,2-diyl groups. A a42 , A a43 and A a44 Examples of substituents on the divalent saturated hydrocarbon group represented by include hydroxyl groups and alkoxy groups having 1 to 6 carbon atoms. s is preferably 0.

[0162] In the group represented by formula (a-g1), X a42 The following are examples of groups whose members are -O-, -CO-, -CO-O-, or -O-CO-. In the following examples, * and ** represent bonds, respectively, and ** is -O-CO-R a42 This is a combination of the two. TIFF0007867324000100.tif53162

[0163] The structural units represented by formula (a4-1) are the structural units shown below and the R in the structural units represented by formula (a4-1) in the structural units below. a41 One example is a structural unit in which the corresponding methyl group is replaced by a hydrogen atom. TIFF0007867324000101.tif167144

[0164] TIFF0007867324000102.tif66133

[0165] The structural unit represented by formula (a4-1) is preferably the structural unit represented by formula (a4-2). TIFF0007867324000103.tif4366[In formula (a4-2), R f5represents a hydrogen atom or a methyl group. L 44 This represents an alkanediyl group having 1 to 6 carbon atoms, and the -CH2- contained in the alkanediyl group may be replaced with -O- or -CO-. R f6 This represents a saturated hydrocarbon group having 1 to 20 fluorine atoms. However, L 44 and R f6 The upper limit for the total number of carbon atoms is 21.

[0166] L 44 The alkanediyl group with 1 to 6 carbon atoms is A a41 Examples of groups similar to those exemplified by the alkanediyl group in [reference] include [example]. R f6 The saturated hydrocarbon group is R a42 Similar to the examples given earlier, the same types of bases can be cited. L 44 In this compound, the alkanediyl group having 1 to 6 carbon atoms is preferably an alkanediyl group having 2 to 4 carbon atoms, and more preferably an ethylene group.

[0167] Examples of structural units represented by equation (a4-2) include those represented by equations (a4-1-1) to (a4-1-11), respectively. f5 A structural unit in which the corresponding methyl group is replaced by a hydrogen atom can also be cited as a structural unit represented by formula (a4-2).

[0168] An example of a structural unit (a4) is the structural unit represented by formula (a4-3). TIFF0007867324000104.tif5771[In formula (a4-3), R f7 represents a hydrogen atom or a methyl group. L 5 This represents an alkanediyl group with 1 to 6 carbon atoms. A f13 This represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, which may contain a fluorine atom. X f12This represents *-O-CO- or *-CO-O- (* is A f13 This represents a combination with ). A f14 This 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 them has a fluorine atom, L 5 , A f13 and A f14 The upper limit for the total number of carbon atoms is 20.

[0169] L 5 The alkanediyl group in A is a41 Examples of such groups include those similar to the alkanediyl group in the divalent saturated hydrocarbon group. A f13 The divalent saturated hydrocarbon group which may have a fluorine atom is preferably a divalent aliphatic saturated hydrocarbon group which may have a fluorine atom and a divalent alicyclic saturated hydrocarbon group which may have a fluorine atom, and more preferably a perfluoroalkanediyl group. Examples of divalent aliphatic hydrocarbon groups that may contain a fluorine atom include methylene groups, ethylene groups, propanediyl groups, butanediyl groups, and pentanediyl groups, as well as perfluoroalkanediyl groups such as difluoromethylene groups, perfluoroethylene groups, perfluoropropanediyl groups, perfluorobutanediyl groups, and perfluoropentanediyl groups. The divalent alicyclic hydrocarbon group, which may contain a fluorine atom, may be monocyclic or polycyclic. Examples of monocyclic groups include cyclohexanediyl and perfluorocyclohexanediyl groups. Examples of polycyclic groups include adamantanediyl, norbornanediyl, and perfluoroadamantanediyl groups. A f14 The saturated hydrocarbon group and the saturated hydrocarbon group which may have a fluorine atom are R a42The same groups as those exemplified above can be cited. Among them, trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, Preferred groups include alkyl fluorides such as hexyl group, perfluorohexyl group, heptyl group, perfluoroheptyl group, octyl group, and perfluorooctyl group, cyclopropylmethyl group, cyclopropyl group, cyclobutylmethyl group, cyclopentyl group, cyclohexyl group, perfluorocyclohexyl group, adamantyl group, adamantylmethyl group, adamantyldimethyl group, norbornyl group, norbornylmethyl group, perfluoroadamantyl group, and perfluoroadamantylmethyl group.

[0170] In equation (a4-3), L 5 An ethylene group is preferred. A f13 The divalent saturated hydrocarbon group is preferably a group containing a divalent chain hydrocarbon group having 1 to 6 carbon atoms and a divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a divalent chain hydrocarbon group having 2 to 3 carbon atoms. A f14 The saturated hydrocarbon group is preferably a group containing a chain hydrocarbon group having 3 to 12 carbon atoms and an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a group containing a chain hydrocarbon group having 3 to 10 carbon atoms and an alicyclic hydrocarbon group having 3 to 10 carbon atoms. Among these, A f14 The group is preferably a group containing an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group.

[0171] Examples of structural units represented by equation (a4-3) include those represented by equations (a4-1'-1) to (a4-1'-11), respectively.f7 A structural unit in which the corresponding methyl group is replaced by a hydrogen atom can also be cited as a structural unit represented by formula (a4-3).

[0172] Another example of a structural unit (a4) is the structural unit represented by formula (a4-4). TIFF0007867324000105.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 through j5 each independently represent an integer from 1 to 6. R f22 This represents a saturated hydrocarbon group with 1 to 10 carbon atoms containing a fluorine atom.

[0173] R f22 The saturated hydrocarbon group is R a42 Examples include the same saturated hydrocarbon group represented by R. f22 The C1-C10 alkyl group having a fluorine atom or the C1-C10 alicyclic hydrocarbon group having a fluorine atom is preferred, the C1-C10 alkyl group having a fluorine atom is more preferred, and the C1-C6 alkyl group having a fluorine atom is even more preferred.

[0174] In equation (a4-4), A f21 As for, -(CH2) j1 - is preferred, an ethylene group or a methylene group is more preferred, and a methylene group is even more preferred.

[0175] As a structural unit represented by formula (a4-4), for example, the following structural unit and the structural unit represented by the following formula, R in structural unit (a4-4) f21 One example is a structural unit in which the corresponding methyl group is replaced by a hydrogen atom. TIFF0007867324000106.tif80148

[0176] If resin (A) has structural units (a4), the content of these units is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, and even more preferably 3 to 10 mol%, relative to the total structural units of resin (A).

[0177] <Structural Unit (a5)> Examples of non-eliminating hydrocarbon groups in structural unit (a5) include groups having linear, branched, or cyclic hydrocarbon groups. Among these, structural unit (a5) is preferably a group having an alicyclic hydrocarbon group. An example of a structural unit (a5) is the structural unit represented by formula (a5-1). TIFF0007867324000107.tif3971[In formula (a5-1), R 51 represents a hydrogen atom or a methyl group. R 52 This represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and the hydrogen atoms contained in this alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms. L 55 This represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the -CH2- contained in the saturated hydrocarbon group may be replaced by -O- or -CO-.

[0178] R 52 The alicyclic hydrocarbon group in this compound may be either monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples of polycyclic alicyclic hydrocarbon groups include adamantyl and norbornyl groups. Examples of aliphatic hydrocarbon groups having 1 to 8 carbon atoms include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, and 2-ethylhexyl. Examples of substituted alicyclic hydrocarbon groups include the 3-methyladamantyl group. R 52 Preferably, it is an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and more preferably, an adamantyl group, a norbornyl group, or a cyclohexyl group. L 55 Examples of divalent saturated hydrocarbon groups in this context include divalent chain-type saturated hydrocarbon groups and divalent alicyclic saturated hydrocarbon groups, with divalent chain-type saturated hydrocarbon groups being preferred. Examples of divalent chain-type saturated hydrocarbon groups include methylene groups, ethylene groups, propanediyl groups, butanediyl groups, and pentanediyl groups, which are all types of alkanediyl groups. The divalent alicyclic saturated hydrocarbon group may be monocyclic or polycyclic. Examples of monocyclic alicyclic saturated hydrocarbon groups include cycloalkanediyl groups such as cyclopentanediyl and cyclohexanediyl. Examples of polycyclic divalent alicyclic saturated hydrocarbon groups include adamantanediyl and norbornanediyl.

[0179] L 55 Groups in which the -CH2- contained in the divalent saturated hydrocarbon group represented by is replaced with -O- or -CO- include, for example, the groups represented by formulas (L1-1) to (L1-4). In the following formulas, * and ** represent bonds, respectively, and * represents a bond with an oxygen atom. TIFF0007867324000108.tif18165 formula (L1-1), X x1 This represents *-O-CO- or *-CO-O- (* is L x1 This represents a combination with ). L x1 This represents a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms. L x2 This 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), Lx3 This represents a divalent aliphatic saturated hydrocarbon group with 1 to 17 carbon atoms. L x4 This 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 This represents a divalent aliphatic saturated hydrocarbon group with 1 to 15 carbon atoms. L x6 and L x7 Each of these 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 This represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms. W x1 This represents a divalent alicyclic saturated hydrocarbon group with 3 to 15 carbon atoms. However, L x8 , L x9 and W x1 The total number of carbon atoms is 15 or less.

[0180] L x1 Preferably, this is a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group. L x2 Preferably, it is a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond. L x3 Preferably, it is a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms. L x4 Preferably, it is a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms. L x5Preferably, this is a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group. L x6 Preferably, it is 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 Preferably, it is a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms. L x8 Preferably, it is 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 Preferably, it is 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 Preferably, this is a divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, more preferably a cyclohexanediyl group or an adamantanediyl group.

[0181] Examples of groups represented by formula (L1-1) include the divalent groups shown below. TIFF0007867324000109.tif23135

[0182] TIFF0007867324000110.tif33117

[0183] Examples of groups represented by formula (L1-2) include the divalent groups shown below. TIFF0007867324000111.tif23130

[0184] Examples of groups represented by formula (L1-3) include the divalent groups shown below. TIFF0007867324000112.tif15145

[0185] Examples of groups represented by formula (L1-4) include the divalent groups shown below. TIFF0007867324000113.tif26114

[0186] L 55 Preferably, it is a single bond or a group represented by formula (L1-1).

[0187] The structural units (a5-1) are the structural units shown below and the R in the structural unit (a5-1) within the structural units below. 51 One example is a structural unit in which the corresponding methyl group is replaced by a hydrogen atom. TIFF0007867324000114.tif75150

[0188] TIFF0007867324000115.tif36150 If resin (A) has structural units (a5), the content of these units is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, and even more preferably 3 to 15 mol%, relative to the total structural units of resin (A). <Structural Unit (a6)> Structural unit (a6) is a structural unit having an -SO2- group, and it is preferable that it has an -SO2- group in its side chain. A structural unit having an -SO2- group may have a linear structure having an -SO2- group, a branched structure having an -SO2- group, or a cyclic structure (monocyclic and polycyclic) having an -SO2- group. Preferably, it is a structural unit having a cyclic structure having an -SO2- group, and more preferably, it is a structural unit having a cyclic structure (sultone ring) containing -SO2-O-.

[0189] As a sultone ring, the following equation (T 1 -1), formula (T 1 -2), formula (T 1 -3) and formula (T 1 A ring represented by (T-4) is an example. The bonding site can be at any position. The sultone ring may be monocyclic, but it is preferably polycyclic. A polycyclic sultone ring means a bridging ring containing -SO2-O- as the atomic group constituting the ring, and is represented by formula (T 1 -1) and formula (T 1A ring represented by equation (T) is an example. A Sultone ring is given by equation (T 1 As shown in (2), the ring may contain heteroatoms in addition to -SO2-O- as part of the atomic group constituting the ring. Examples of heteroatoms include oxygen atoms, sulfur atoms, or nitrogen atoms, with oxygen atoms being preferred. TIFF0007867324000116.tif3187

[0190] The sultone ring may have substituents, and examples of substituents include C1-C12 alkyl groups which may have a halogen atom or a hydroxyl group, halogen atoms, hydroxyl groups, cyano groups, C1-C12 alkoxy groups, C6-C12 aryl groups, C7-C12 aralkyl groups, glycidyloxy groups, C2-C12 alkoxycarbonyl groups, and C2-C4 alkylcarbonyl groups.

[0191] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. Examples of alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, and decyl groups, preferably alkyl groups having 1 to 6 carbon atoms, and more preferably methyl groups. Examples of alkyl groups having a halogen atom include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoroisopropyl, perfluorobutyl, perfluorosec-butyl, perfluorotert-butyl, perfluoropentyl, perfluorohexyl, trichloromethyl, tribromomethyl, and triiodomethyl, with trifluoromethyl being preferred. Examples of alkyl groups having a hydroxyl group include hydroxymethyl groups and 2-hydroxyethyl groups. Examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy, and dodecyloxy groups. Examples of aryl groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumyl, mesityl, biphenyl, phenanthryl, 2,6-diethylphenyl, and 2-methyl-6-ethylphenyl. Examples of aralkyl groups include benzyl, phenethyl, phenylpropyl, naphthylmethyl, and naphthylethyl groups. Examples of alkoxycarbonyl groups include groups in which an alkoxy group such as a methoxycarbonyl group or an ethoxycarbonyl group is bonded to a carbonyl group, preferably an alkoxycarbonyl group having 6 or fewer carbon atoms, and more preferably a methoxycarbonyl group. Examples of alkylcarbonyl groups include acetyl, propionyl, and butyryl groups.

[0192] From the viewpoint of ease of production of monomers that lead to structural unit (a6), a sultone ring without substituents is preferred. As the sultone ring, the ring represented by the following formula (T1') is preferred. TIFF0007867324000117.tif3172[In formula (T1'), X 11 represents an oxygen atom, a sulfur atom, or a methylene group. R 41 This represents a C1-C12 alkyl group which may have a halogen atom or a hydroxyl group, a halogen atom, a hydroxyl group, a cyano group, a C1-C12 alkoxy group, a C6-C12 aryl group, a C7-C12 aralkyl group, a glycidyloxy group, a C2-C12 alkoxycarbonyl group, or a C2-C4 alkylcarbonyl group. ma represents an integer from 0 to 9. When ma is 2 or greater, multiple R 41 They may be the same or different. The connection point can be at any location. X 11 This is preferably an oxygen atom or a methylene group, and more preferably a methylene group. R41 Examples include substituents similar to those of a sultone ring, and C1-C12 alkyl groups which may have a halogen atom or a hydroxyl group are preferred.

[0193] As a sultone ring, the ring represented by formula (T1) is more preferable. TIFF0007867324000118.tif3149[In formula (T1), R 8 This represents a C1-C12 alkyl group which may have a halogen atom or a hydroxyl group, a halogen atom, a hydroxyl group, a cyano group, a C1-C12 alkoxy group, a C6-C12 aryl group, a C7-C12 aralkyl group, a glycidyloxy group, a C2-C12 alkoxycarbonyl group, or a C2-C4 alkylcarbonyl group. m represents an integer from 0 to 9. When m is 2 or greater, multiple R 8 They may be the same or different. The connection point can be at any location.

[0194] R 8 R 41 Similar examples include the above. In formula (T1'), ma and in formula (T1), m are preferably 0 or 1, and more preferably 0.

[0195] The following rings are examples of rings represented by formula (T1') and formula (T1). The bonding site is at an arbitrary position. TIFF0007867324000119.tif57165

[0196] Structural units having a sultone ring preferably have the following groups. * in the following groups indicates a bonding site. TIFF0007867324000120.tif51165

[0197] The structural unit having the -SO2- group preferably further has a group derived from a polymerizable group. Examples of polymerizable groups include vinyl group, acryloyl group, methacryloyl group, acryloyloxy group, methacryloyloxy group, acryloylamino group, methacryloylamino group, acryloylthio group, and methacryloylthio group. In particular, the monomer that leads to the structural unit (a6) is preferably a monomer having an ethylenically unsaturated bond, and more preferably a (meth)acrylic monomer.

[0198] The structural unit (a6) is preferably a structural unit represented by formula (Ix). TIFF0007867324000121.tif4956 [In formula (Ix), R x This represents an alkyl group having 1 to 6 carbon atoms, which may contain a halogen atom, a hydrogen atom, or a halogen atom. A xx is an oxygen atom, -N(R c )- or represents a sulfur atom. A x represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the -CH2- contained in the saturated hydrocarbon group is -O-, -CO-, or -N(R d )- may be replaced with this. X 11 represents an oxygen atom, a sulfur atom, or a methylene group. R 41 This represents a C1-C12 alkyl group which may have a halogen atom or a hydroxyl group, a halogen atom, a hydroxyl group, a cyano group, a C1-C12 alkoxy group, a C6-C12 aryl group, a C7-C12 aralkyl group, a glycidyloxy group, a C2-C12 alkoxycarbonyl group, or a C2-C4 alkylcarbonyl group. ma represents an integer from 0 to 9. When ma is 2 or greater, multiple R 41 They may be the same or different. R c and R d Each of these independently represents either a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0199] R x Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. R x Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl groups, preferably alkyl groups having 1 to 4 carbon atoms, and more preferably methyl or ethyl groups. R x Examples of alkyl groups having a halogen atom include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoroisopropyl, perfluorobutyl, perfluorosec-butyl, perfluorotert-butyl, perfluoropentyl, perfluorohexyl, trichloromethyl, tribromomethyl, and triiodomethyl. R x Preferably, it is 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.

[0200] A x Examples of divalent saturated hydrocarbon groups include linear alkanediyl groups, branched alkanediyl groups, and monocyclic or polycyclic divalent alicyclic saturated hydrocarbon groups, and combinations of two or more of these groups are also acceptable. Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group Linear alkanediyl groups such as dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group, and propane-2,2-diyl group; Branched alkanediyl groups such as butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group; Monocyclic, divalent, alicyclic saturated hydrocarbon groups such as cycloalkanediyl groups, 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.

[0201] R 41 , X 11 And ma can be the same as in equation (T1'). Examples of sultone rings include those mentioned above, and among them, those with specified bonding positions are preferred.

[0202] The following are examples of structural units (a6): TIFF0007867324000122.tif104168

[0203] In particular, structural units represented by formulas (a6-1), (a6-2), (a6-6), (a6-7), (a6-8), and (a6-12) are preferred, and structural units represented by formulas (a6-1), (a6-2), (a6-7), and (a6-8) are more preferred. If resin (A) has structural units (a6), the content of these units is preferably 1 to 50 mol%, more preferably 2 to 40 mol%, and even more preferably 3 to 30 mol%, relative to the total structural units of resin (A).

[0204] <Structural Unit (II)> The resin (A) may further contain structural units that decompose upon exposure to generate acid (hereinafter sometimes referred to as "structural unit (II)"). Specifically, structural unit (II) is the structural unit described in Japanese Patent Application Publication No. 2016-79235, and is preferably a structural unit having a sulfonate group or carboxylate group and an organic cation in its side chain, or a structural unit having a sulfonio group and an organic anion in its side chain.

[0205] The structural unit having a sulfonate group or carboxylate group and an organic cation in its side chain is preferably the structural unit represented by formula (II-2-A'). TIFF0007867324000123.tif35104[In formula (II-2-A'), X III3 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the -CH2- contained in the saturated hydrocarbon group may be replaced with -O-, -S-, or -CO-, and the hydrogen atom contained in the saturated hydrocarbon group may be replaced with a halogen atom, an alkyl group having 1 to 6 carbon atoms which may contain a halogen atom, or a hydroxyl group. A x1 This represents an alkanediyl group having 1 to 8 carbon atoms, and the hydrogen atoms contained in the alkanediyl group may be substituted with fluorine atoms or perfluoroalkyl groups having 1 to 6 carbon atoms. RA - This represents a sulfonate group or a carboxylate group. R III3This represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms that may contain a halogen atom. ZA + This represents an organic cation.

[0206] R III3 Examples of halogen atoms represented by this formula include fluorine, chlorine, bromine, and iodine atoms. R III3 A C1-C6 alkyl group which may have a halogen atom represented by R is a8 Examples include alkyl groups having 1 to 6 carbon atoms that may contain a halogen atom represented by . A x1 Examples of C1-C8 alkanediyl groups represented by include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group. A X1 Examples of C1-C6 perfluoroalkyl groups that may be substituted include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoroisopropyl, perfluorobutyl, perfluorosec-butyl, perfluorotert-butyl, perfluoropentyl, and perfluorohexyl groups. X III3 Examples of divalent saturated hydrocarbon groups having 1 to 18 carbon atoms represented by include linear or branched alkanediyl groups, monocyclic or polycyclic divalent alicyclic saturated hydrocarbon groups, and combinations thereof. Specifically, linear alkane diyl groups such as methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, etc.; butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, etc. Examples include branched alkanediyl groups such as pan-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group; cycloalkanediyl groups such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, and cyclooctane-1,5-diyl group; 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 adamantane-2,6-diyl group. Examples of groups in which the -CH2- group in a saturated hydrocarbon group is replaced by -O-, -S-, or -CO- include the divalent groups represented by formulas (X1) to (X53). However, the number of carbon atoms before the -CH2- group in the saturated hydrocarbon group is replaced by -O-, -S-, or -CO- is 17 or less. In the following formulas, * and ** represent bonding sites, and * is A x1 This represents a combination of two things. TIFF0007867324000124.tif145161

[0207] X 3 This represents a divalent saturated hydrocarbon group with 1 to 16 carbon atoms. X 4 This represents a divalent saturated hydrocarbon group with 1 to 15 carbon atoms. X 5 This represents a divalent saturated hydrocarbon group with 1 to 13 carbon atoms. X 6 This represents a divalent saturated hydrocarbon group with 1 to 14 carbon atoms. X 7 This represents a trivalent saturated hydrocarbon group with 1 to 14 carbon atoms. X 8This represents a divalent saturated hydrocarbon group with 1 to 13 carbon atoms.

[0208] ZA in equation (II-2-A') + This is the cation Z1 in the salt represented by formula (B1). + Similar examples include the above.

[0209] The structural unit represented by formula (II-2-A') is preferably the structural unit represented by formula (II-2-A). TIFF0007867324000125.tif38109 [In formula (II-2-A), R III3 , X III3 and ZA + This expresses the same meaning as above. z2A represents an integer between 0 and 6. R III2 and R III4 Each of these independently represents a hydrogen atom, a fluorine atom, or a perfluoroalkyl group having 1 to 6 carbon atoms, and when z2A is 2 or more, multiple R III2 and R III4 They may be the same or they may be different. Q a and Q b Each of these independently represents either a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. R III2 , R III4 Q a and Q b As perfluoroalkyl groups having 1 to 6 carbon atoms, as represented by the aforementioned Q b1 Examples include perfluoroalkyl groups with 1 to 6 carbon atoms, represented by [the formula shown].

[0210] The structural unit represented by formula (II-2-A) is preferably the structural unit represented by formula (II-2-A-1). TIFF0007867324000126.tif5577 [In formula (II-2-A-1), R III2 , R III3 , R III4 Q a Qb and ZA + This expresses the same meaning as above. R III5 This represents a saturated hydrocarbon group with 1 to 12 carbon atoms. z2A1 represents an integer between 0 and 6. X I2 This represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms, where the -CH2- group may be replaced with -O-, -S-, or -CO-, and the hydrogen atoms in the saturated hydrocarbon group may be substituted with halogen atoms or hydroxyl groups. R III5 Examples of saturated hydrocarbon groups having 1 to 12 carbon atoms represented by include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups. X I2 As a divalent saturated hydrocarbon group represented by , X III3 Examples include divalent saturated hydrocarbon groups represented by .

[0211] As a structural unit represented by formula (II-2-A-1), the structural unit represented by formula (II-2-A-2) is even more preferable. TIFF0007867324000127.tif5287 [In formula (II-2-A-2), R III3 , R III5 and ZA + This expresses the same meaning as above. m and nA independently represent either 1 or 2.

[0212] Examples of structural units represented by formula (II-2-A') include the following structural unit, R III3 Examples include structural units in which the group corresponding to the methyl group is replaced by a hydrogen atom, a halogen atom (e.g., a fluorine atom), or a C1-C6 alkyl group which may have a halogen atom (e.g., a trifluoromethyl group), and structural units described in International Publication No. 2012 / 050015. ZA+ This represents an organic cation. TIFF0007867324000128.tif86163

[0213] The structural unit having a sulfonio group and an organic anion in its side chain is preferably the structural unit represented by formula (II-1-1). TIFF0007867324000129.tif3791 [In formula (II-1-1), A II1 This represents a single bond or a divalent linking group. R II1 This represents a divalent aromatic hydrocarbon group with 6 to 18 carbon atoms. R II2 and R II3 Each of these independently represents a hydrocarbon group with 1 to 18 carbon atoms, and R II2 and R II3 These atoms may bond to each other, forming a ring with the sulfur atom to which they are bonded. R II4 This represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms that may contain a halogen atom. A - This represents an organic anion. R II1 Examples of divalent aromatic hydrocarbon groups having 6 to 18 carbon atoms, represented by this formula, include phenylene groups and naphthylene groups. R II2 and R II3 Examples of hydrocarbon groups represented by this symbol include alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these. R II4 Examples of halogen atoms represented by this formula include fluorine, chlorine, bromine, and iodine atoms. R II4 A C1-C6 alkyl group which may have a halogen atom represented by R is a8 Examples include alkyl groups having 1 to 6 carbon atoms that may contain a halogen atom represented by . A II1Examples of divalent linking groups represented by include divalent saturated hydrocarbon groups having 1 to 18 carbon atoms, and the -CH2- contained in the divalent saturated hydrocarbon group may be replaced with -O-, -S-, or -CO-. Specifically, X III3 Examples include divalent saturated hydrocarbon groups with 1 to 18 carbon atoms, represented by .

[0214] The structural units containing cations in formula (II-1-1) are the structural units represented below and R II4 Examples include structural units in which the group equivalent to the methyl group is replaced by a hydrogen atom, a fluorine atom, a trifluoromethyl group, etc. TIFF0007867324000130.tif84130

[0215] A - Examples of organic anions represented by include sulfonic acid anions, sulfonylimide anions, sulfonylmethide anions, and carboxylic acid anions. - The organic anion represented by is preferably a sulfonic acid anion, and more preferably a sulfonic acid anion that is contained in the salt represented by formula (B1) above. The sulfonylimide anion, sulfonylmethide anion, and carboxylic acid anion are anions AI contained in the salt represented by formula (I) above. - It is preferable that it be so.

[0216] Examples of structural units represented by formula (II-1-1) include the following structural units: TIFF0007867324000131.tif88149

[0217] When resin (A) contains structural unit (II), the content of structural unit (II) is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, and even more preferably 3 to 10 mol%, relative to the total structural units of resin (A).

[0218] The resin (A) may have structural units other than those described above, and examples of such structural units include structural units well known in the art.

[0219] The resin (A) is preferably a resin consisting of structural units (a1) and structural units (s), that is, a copolymer of monomer (a1) and monomer (s). The structural unit (a1) is preferably at least one selected from the group consisting of structural unit (a1-0), structural unit (a1-1), and structural unit (a1-2) (preferably a structural unit having a cyclohexyl group and a cyclopentyl group), more preferably at least two, and even more preferably at least two selected from the group consisting of structural unit (a1-1) and structural unit (a1-2). The structural unit (s) is preferably at least one selected from the group consisting of structural units (a2) and structural units (a3). The structural unit (a2) is preferably structural unit (a2-1) or structural unit (a2-A). The structural unit (a3) ​​is preferably at least one selected from the group consisting of structural units represented by formula (a3-1), structural units represented by formula (a3-2), and structural units represented by formula (a3-4). Each structural unit constituting resin (A) may be used individually or in combination of two or more types, and these structural units can be produced by known polymerization methods (e.g., radical polymerization) using monomers that derive these structural units. The content of each structural unit in resin (A) can be adjusted by the amount of monomer used in polymerization. The weight-average molecular weight of resin (A) is preferably 2,000 or more (more preferably 2,500 or more, 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 the value obtained by gel permeation chromatography under the conditions described in the examples.

[0220] <Resins other than resin (A)> The resist composition of the present invention may also contain resins other than resin (A). Examples of resins other than resin (A) include resins containing structural unit (a4) or structural unit (a5) (hereinafter sometimes referred to as resin (X)). Among the resins (X), resins containing structural units (a4) are preferred. In resin (X), the content of structural unit (a4) is preferably 30 mol% or more, more preferably 40 mol% or more, and even more preferably 45 mol% or more, relative to the total amount of all structural units in resin (X). Structural units that resin (X) may further have include structural unit (a1), structural unit (a2), structural unit (a3), and structural units derived from other known monomers. In particular, it is preferable that resin (X) consists only of structural unit (a4) and / or structural unit (a5). Each structural unit constituting resin (X) may be used individually or in combination of two or more types, and these structural units can be produced by known polymerization methods (e.g., radical polymerization) using monomers that induce these structural units. The content of each structural unit in resin (X) can be adjusted by the amount of monomer used in polymerization. The weight-average molecular weight of resin (X) is preferably 6,000 or more (more preferably 7,000 or more) and 80,000 or less (more preferably 60,000 or less). The means for measuring the weight-average molecular weight of resin (X) is the same as in the case of resin (A).

[0221] If the resist composition of the present invention contains resin (X), the content of resin (X) is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, even more preferably 1 to 40 parts by mass, even more preferably 1 to 30 parts by mass, and particularly preferably 1 to 8 parts by mass, per 100 parts by mass of resin (A).

[0222] The content of resin (A) in the resist composition is preferably 80% to 99% by mass, and more preferably 90% to 99% by mass, relative to the solid content of the resist composition. Furthermore, if resins other than resin (A) are included, the total content of resin (A) and the other resins is preferably 80% to 99% by mass, and more preferably 90% to 99% by mass, relative to the solid content of the resist composition. In this specification, "solid content of the resist composition" means the total amount of components of the resist composition excluding the solvent (E), which will be described later. The solid content of the resist composition and the resin content thereto can be measured by known analytical means such as liquid chromatography or gas chromatography.

[0223] <Solvent (E)> The solvent (E) content in the resist composition is usually 90% to 99.9% by mass, preferably 92% to 99% by mass, and more preferably 94% to 99% by mass. The solvent (E) content can be measured by known analytical means such as liquid chromatography or gas chromatography.

[0224] Examples of 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; and cyclic esters such as γ-butyrolactone. One of solvents (E) may be used alone, or two or more may be used.

[0225] <Quencher (C)> Quencher (C) can be a basic nitrogen-containing organic compound or a salt that generates an acid weaker than the acid generated from the acid generator (B). When the resist composition contains quencher (C), the quencher (C) content is preferably about 0.01 to 15% by mass, more preferably about 0.01 to 10% by mass, even more preferably about 0.1 to 5% by mass, and even more preferably about 0.1 to 3% by mass, based on the solid content of the resist composition. Basic nitrogen-containing organic compounds include amines and ammonium salts. Amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines, and tertiary amines.

[0226] Examples of 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, trib Tylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldi Decylamine, dicyclohexylmethylamine, tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, 2,2'-methylenebisaniline, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 1,2-di(2-P Examples include lysyl)ethane, 1,2-di(4-pyridyl)ethane, 1,2-di(2-pyridyl)ethene, 1,2-di(4-pyridyl)ethene, 1,3-di(4-pyridyl)propane, 1,2-di(4-pyridyloxy)ethane, di(2-pyridyl)ketone, 4,4'-dipyridyl sulfide, 4,4'-dipyridyl disulfide, 2,2'-dipyridylamine, 2,2'-dipicolylamine, bipyridine, etc. Diisopropylaniline is preferred, and 2,6-diisopropylaniline is more preferred.

[0227] 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.

[0228] 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 a salt that generates a carboxylic acid with a lower acidity than the acid generated from the acid generator (B) (a salt having a carboxylic acid anion), and more preferably a weak acid inner salt (D). TIFF0007867324000132.tif94163

[0229] Examples of the weak acid inner salt (D) include the following salts. TIFF0007867324000133.tif72165

[0230] 〈Other components〉 The resist composition of the present invention may optionally contain components other than those described above (hereinafter sometimes referred to as "other components (F)"). There are no particular limitations on other components (F), and additives known in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, etc., can be used.

[0231] <Preparation of resist composition> The resist composition of the present invention can be prepared by mixing a salt (I), a resin (A), an acid generator (B), and, if necessary, a resin other than the resin (A) used, a solvent (E), a quencher (C), and other components (F). The mixing order is arbitrary and not particularly limited. The mixing temperature can be selected from 10 to 40°C, depending on the type of resin, the solubility of the resin in the solvent (E), etc. The mixing time can be selected from 0.5 to 24 hours, depending on the mixing temperature. There are no particular restrictions on the mixing method, and stirring or other methods can be used. After mixing the components, it is preferable to filter the mixture using a filter with a pore size of approximately 0.003 to 0.2 μm.

[0232] <Method for manufacturing resist patterns> The method for manufacturing a resist pattern of the present invention is: (1) A step of applying the resist composition of the present invention onto a substrate, (2) A step of drying the applied composition to form a composition layer, (3) A step of exposing the composition layer, (4) A step of heating the composition layer after exposure, (5) Includes a step of developing the composition layer after heating. The resist composition can be applied to a substrate using commonly used equipment such as a spin coater. Examples of substrates include inorganic substrates such as silicon wafers, and already formed resist films. Before applying the resist composition, the substrate may be cleaned, and an anti-reflective film may be formed on the substrate. The solvent is removed and a composition layer is formed by drying the coated composition. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called pre-baking), or by using a vacuum device. The heating temperature is preferably 50 to 200°C, and the heating time is preferably 10 to 180 seconds. The pressure when drying under reduced pressure is 1 to 1.0 × 10⁻⁶. 5 It is preferable that the pressure be around Pa. The resulting composition layer is typically exposed using an exposure machine. The exposure machine may be an immersion exposure machine. Various types of exposure light sources can be used, including those that emit ultraviolet laser light such as KrF excimer lasers (wavelength 248 nm), ArF excimer lasers (wavelength 193 nm), and F2 excimer lasers (wavelength 157 nm), those that emit far-ultraviolet or vacuum-ultraviolet harmonic laser light by wavelength conversion of laser light from a solid-state laser light source (such as a YAG or semiconductor laser), electron beams, and those that irradiate with ultra-ultraviolet (EUV) light. In this specification, the irradiation of these radiations is sometimes collectively referred to as "exposure." During exposure, exposure is usually performed through a mask corresponding to the desired pattern. If the exposure light source is an electron beam, exposure may be performed by direct drawing without using a mask. The composition layer after exposure is subjected to heat treatment (so-called post-exposure baking) to promote the deprotection reaction at acid-unstable groups. The heating temperature is usually around 50 to 200°C, preferably around 70 to 150°C. Chemical treatment (silylation) may be performed to adjust the hydrophilicity or hydrophobicity of the resin on the surface side of the composition after heating. Alternatively, before development, the steps of coating, drying, exposure, and heating of the resist composition of the present invention may be repeatedly performed on the composition layer after exposure. The heated composition layer is typically developed using a developing apparatus and a developing solution. Development methods include the dip method, paddle method, spray method, and dynamic dispensing method. The development temperature is preferably, for example, 5 to 60°C, and the development time is preferably, for example, 5 to 300 seconds. By selecting the type of developing solution as described below, a positive-type resist pattern or a negative-type resist pattern can be manufactured. When producing a positive resist pattern from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer can be any alkaline aqueous solution used in this field. For example, aqueous solutions of tetramethylammonium hydroxide or (2-hydroxyethyl)trimethylammonium hydroxide (commonly known as choline) can be used. The alkaline developer may also contain a surfactant. It is preferable to wash the resist pattern with ultrapure water after development, and then remove any remaining water on the substrate and pattern. When manufacturing a negative-type resist pattern from the resist composition of the present invention, a developer containing an organic solvent (hereinafter sometimes referred to as "organic developer") is used as the developer. Examples of organic solvents contained in organic developers include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycol ether solvents such as propylene glycol monomethyl ether; amide solvents such as N,N-dimethylacetamide; and aromatic hydrocarbon solvents such as anisole. In the organic developer, the content of the organic solvent is preferably 90% by 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 composed of only organic solvents. Among these, organic developers containing butyl acetate and / or 2-heptanone are preferred. 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 butyl acetate and / or 2-heptanone alone. Organic developers may contain surfactants. Furthermore, organic developers may contain trace amounts of water. During development, the development process may be stopped by substituting a different type of solvent for the organic developer. It is preferable to wash the developed resist pattern with a rinsing solution. The rinsing solution is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, preferably an alcohol solvent or an ester solvent. After cleaning, it is preferable to remove any remaining rinse solution from the substrate and patterns.

[0233] <Application> The resist composition of the present invention is suitable as a resist composition for KrF excimer laser exposure, an ArF excimer laser exposure, an electron beam (EB) exposure, or an EUV exposure, and is particularly suitable as a resist composition for electron beam (EB) exposure or an EUV exposure, and is useful for semiconductor microfabrication. [Examples]

[0234] The present invention will be described in more detail with reference to examples. In the examples, "%" and "parts" representing the content or amount used are based on mass unless otherwise specified. The weight-average molecular weight was determined by gel permulation chromatography. The analytical conditions for gel permulation chromatography are as follows: Column: TSKgel Multipore HXL-M x 3 + guard column (manufactured by Tosoh Corporation) Eluent: Tetrahydrofuran Flow rate: 1.0mL / min Detector: RI detector Column temperature: 40℃ Injection volume: 100μl Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation) The structure of the compound was confirmed by measuring the molecular ion peak using mass spectrometry (LC: Agilent 1100, MASS: Agilent LC / MSD). In the following examples, the value of this molecular ion peak is indicated as "MASS".

[0235] Example 1: Synthesis of the salt represented by formula (I-8) TIFF0007867324000134.tif97161 1.57 parts of the salt represented by formula (I-8-a), 1.10 parts of the compound represented by formula (I-8-b), and 10 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. 0.44 parts of potassium carbonate were added to the resulting mixture and stirred at 23°C for 30 minutes, then stirred at 90°C for 3 hours to obtain a mixture containing the salt represented by formula (I-8-c). After cooling the resulting mixture to 23°C, 12 parts of 5% aqueous oxalic acid were added and stirred at 23°C for 30 minutes, then 3.20 parts of the salt represented by formula (I-8-d) were added and stirred at 23°C for 7 hours. 30 parts of chloroform and 30 parts of deionized water were added to the resulting reaction product and stirred at 23°C for 30 minutes, then the organic layer was separated by liquid-liquid extraction. To the obtained organic layer, 30 parts of deionized water were added and the mixture was stirred at 23°C for 30 minutes. The organic layer was then separated and removed. This washing procedure was repeated 7 times. After concentrating the obtained organic layer, 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentration residue and the mixture was stirred at 23°C for 30 minutes. The supernatant was removed and the mixture was concentrated to obtain 3.12 parts of the salt represented by formula (I-8). MASS(ESI(+)Spectrum):M + 479.0 MASS(ESI(-)Spectrum):M - 517.1

[0236] Example 2: Synthesis of the salt represented by formula (I-16) TIFF0007867324000135.tif95159 1.57 parts of the salt represented by formula (I-8-a), 1.10 parts of the compound represented by formula (I-8-b), and 10 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. 0.44 parts of potassium carbonate were added to the resulting mixture and stirred at 23°C for 30 minutes, then stirred at 90°C for 3 hours to obtain a mixture containing the salt represented by formula (I-8-c). After cooling the resulting mixture to 23°C, 12 parts of 5% aqueous oxalic acid solution were added and stirred at 23°C for 30 minutes, then 2.85 parts of the salt represented by formula (I-16-d) were added and stirred at 23°C for 7 hours. 30 parts of chloroform and 30 parts of deionized water were added to the resulting reaction product and stirred at 23°C for 30 minutes, then the organic layer was separated by liquid-liquid extraction. To the obtained organic layer, 30 parts of deionized water were added and stirred at 23°C for 30 minutes, after which the organic layer was separated and removed. This washing procedure was repeated 7 times. After concentrating the obtained organic layer, 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentration residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and concentrated to obtain 3.22 parts of the salt represented by formula (I-16). MASS(ESI(+)Spectrum):M + 479.0 MASS(ESI(-)Spectrum):M - 467.1

[0237] Example 3: Synthesis of the salt represented by formula (I-24) TIFF0007867324000136.tif106156 1.57 parts of the salt represented by formula (I-8-a), 1.10 parts of the compound represented by formula (I-8-b), and 10 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. 0.44 parts of potassium carbonate were added to the resulting mixture and stirred at 23°C for 30 minutes, then stirred at 90°C for 3 hours to obtain a mixture containing the salt represented by formula (I-8-c). After cooling the resulting mixture to 23°C, 12 parts of 5% aqueous oxalic acid were added and stirred at 23°C for 30 minutes, then 4.59 parts of the salt represented by formula (I-24-d) were added and stirred at 23°C for 7 hours. 30 parts of chloroform and 30 parts of deionized water were added to the resulting reaction product and stirred at 23°C for 30 minutes, then the organic layer was separated by liquid-liquid extraction. To the obtained organic layer, 30 parts of deionized water were added and stirred at 23°C for 30 minutes, after which the organic layer was separated and removed. This washing procedure was repeated 7 times. After concentrating the obtained organic layer, 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentration residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and concentrated to obtain 4.82 parts of the salt represented by formula (I-24). MASS(ESI(+)Spectrum):M + 479.0 MASS(ESI(-)Spectrum):M - 793.3

[0238] Example 4: Synthesis of the salt represented by formula (I-852) TIFF0007867324000137.tif95159 1.57 parts of the salt represented by formula (I-8-a), 1.19 parts of the compound represented by formula (I-852-b), and 10 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. 0.44 parts of potassium carbonate were added to the resulting mixture and stirred at 23°C for 30 minutes, then stirred at 90°C for 3 hours to obtain a mixture containing the salt represented by formula (I-852-c). After cooling the resulting mixture to 23°C, 12 parts of 5% aqueous oxalic acid were added and stirred at 23°C for 30 minutes, then 2.85 parts of the salt represented by formula (I-16-d) were added and stirred at 23°C for 7 hours. 30 parts of chloroform and 30 parts of deionized water were added to the resulting reaction product and stirred at 23°C for 30 minutes, then the organic layer was separated by liquid-liquid extraction. To the obtained organic layer, 30 parts of deionized water were added and stirred at 23°C for 30 minutes, after which the organic layer was separated and removed. This washing procedure was repeated 7 times. After concentrating the obtained organic layer, 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentration residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and concentrated to obtain 1.98 parts of the salt represented by formula (I-852). MASS(ESI(+)Spectrum):M + 497.0 MASS(ESI(-)Spectrum):M - 467.1

[0239] Example 5: Synthesis of the salt represented by formula (I-1384) TIFF0007867324000138.tif96159 1.57 parts of the salt represented by formula (I-8-a), 0.81 parts of the compound represented by formula (I-1384-b), and 10 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. 0.44 parts of potassium carbonate were added to the resulting mixture and stirred at 23°C for 30 minutes, then stirred at 90°C for 3 hours to obtain a mixture containing the salt represented by formula (I-1384-c). After cooling the resulting mixture to 23°C, 12 parts of 5% aqueous oxalic acid solution were added and stirred at 23°C for 30 minutes, then 2.85 parts of the salt represented by formula (I-16-d) were added and stirred at 23°C for 7 hours. 30 parts of chloroform and 30 parts of deionized water were added to the resulting reaction product and stirred at 23°C for 30 minutes, then the organic layer was separated by liquid-liquid extraction. To the obtained organic layer, 30 parts of deionized water were added and stirred at 23°C for 30 minutes, after which the organic layer was separated and removed. This washing procedure was repeated 7 times. After concentrating the obtained organic layer, 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentration residue and stirred at 23°C for 30 minutes, after which the supernatant was removed and concentrated to obtain 2.98 parts of the salt represented by formula (I-1384). MASS(ESI(+)Spectrum):M + 421.1 MASS(ESI(-)Spectrum):M - 467.1

[0240] Example 6: Synthesis of the salt represented by formula (I-1574) TIFF0007867324000139.tif96159 1.57 parts of the salt represented by formula (I-8-a), 1.81 parts of the compound represented by formula (I-1574-b), and 10 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. 0.44 parts of potassium carbonate were added to the resulting mixture and stirred at 23°C for 30 minutes, then stirred at 90°C for 3 hours to obtain a mixture containing the salt represented by formula (I-1574-c). After cooling the resulting mixture to 23°C, 12 parts of 5% aqueous oxalic acid were added and stirred at 23°C for 30 minutes, then 2.85 parts of the salt represented by formula (I-16-d) were added and stirred at 23°C for 7 hours. 30 parts of chloroform and 30 parts of deionized water were added to the resulting reaction product and stirred at 23°C for 30 minutes, then the organic layer was separated by liquid-liquid extraction. To the obtained organic layer, 30 parts of deionized water were added and the mixture was stirred at 23°C for 30 minutes. The organic layer was then separated and removed. This washing procedure was repeated seven times. After concentrating the obtained organic layer, 1.5 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentration residue and the mixture was stirred at 23°C for 30 minutes. The supernatant was removed and the mixture was concentrated to obtain 4.39 parts of the salt represented by formula (I-1574). MASS(ESI(+)Spectrum):M + 620.9 MASS(ESI(-)Spectrum):M - 467.1

[0241] Resin synthesis The compounds (monomers) used in the synthesis of resin (A) are shown below. Hereafter, these compounds will be referred to as "monomers (a1-1-3)," etc., according to their formula numbers. TIFF0007867324000140.tif46154

[0242] Synthesis Example 1 [Synthesis of Resin A1] Monomers (a1-4-2), (a1-1-3), and (a1-2-6) were used as monomers, and they were mixed in a molar ratio [monomer (a1-4-2):monomer (a1-1-3):monomer (a1-2-6)] of 38:24:38. Furthermore, methyl isobutyl ketone was added to this monomer mixture in an amount equal to 1.5 times the total mass of all monomers. Azobisisobutyronitrile was added to the resulting mixture as an initiator in an amount of 7 mol% relative to the total moles of all monomers, and polymerization was carried out by heating at 85°C for approximately 5 hours. Subsequently, an aqueous solution of p-toluenesulfonic acid (2.5 wt%) equal to 2.0 times the total mass of all monomers was added to the polymerization reaction solution, and after stirring for 6 hours, the solution was separated. The resulting organic layer was poured into a large amount of n-heptane to precipitate the resin, which was then filtered and recovered, yielding a weight-average molecular weight of approximately 5.3 × 10⁻⁶. 3 Resin A1 (polymer) was obtained in a yield of 78%. This resin A1 has the following structural units. TIFF0007867324000141.tif29126

[0243] Synthesis Example 2 [Synthesis of Resin A2] Monomers (a1-4-2) and (a1-2-6) were used as monomers, and they were mixed in a molar ratio [monomer (a1-4-2):monomer (a1-2-6)] of 38:62. Furthermore, methyl isobutyl ketone was added to this monomer mixture in an amount equal to 1.5 times the total mass of all monomers. Azobisisobutyronitrile was added to the resulting mixture as an initiator in an amount of 7 mol% relative to the total moles of all monomers, and polymerization was carried out by heating at 85°C for approximately 5 hours. Subsequently, an aqueous solution of p-toluenesulfonic acid (2.5 wt%) equal to 2.0 times the total mass of all monomers was added to the polymerization reaction solution, and after stirring for 6 hours, the solution was separated. The resulting organic layer was poured into a large amount of n-heptane to precipitate the resin, which was then filtered and recovered, yielding a weight-average molecular weight of approximately 5.4 × 10⁻⁶. 3 Resin A2 (polymer) was obtained in a yield of 89%. This resin A2 has the following structural units. TIFF0007867324000142.tif2887

[0244] Synthesis Example 3 [Synthesis of Resin A3] Monomers (a1-1-3), (a1-2-6), (a2-1-3), (a3-4-2), and (a1-4-2) were used as monomers, and they were mixed in a molar ratio [monomer (a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer (a1-4-2)] of 20:35:3:15:27. Furthermore, methyl isobutyl ketone was added to this monomer mixture in an amount equal to 1.5 times the total mass of all monomers. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at concentrations of 1.2 mol% and 3.6 mol%, respectively, relative to the total amount of monomers, and these mixtures were heated at 73°C for approximately 5 hours. Subsequently, an aqueous solution of p-toluenesulfonic acid (2.5% by weight) in an amount equal to 2.0 times the total mass of monomers was added to the polymerization reaction solution, and after stirring for 12 hours, the solution was separated. The recovered organic layer was poured into a large amount of n-heptane to precipitate the resin, which was then filtered and recovered, yielding a weight-average molecular weight of approximately 5.3 × 10⁶. 3 Resin A3 was obtained with a yield of 63%. This resin A3 has the following structural units. TIFF0007867324000143.tif38154

[0245] Synthesis Example 4 [Synthesis of Resin A4] Monomers (a1-1-3), (a1-2-6), (a2-1-3), (a3-4-2), and (a1-4-13) were used as monomers, and they were mixed in a molar ratio [monomer (a1-1-3):monomer (a1-2-6):monomer (a2-1-3):monomer (a3-4-2):monomer (a1-4-13)] of 20:35:3:15:27. Furthermore, methyl isobutyl ketone was added to this monomer mixture in an amount equal to 1.5 times the total mass of all monomers. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at concentrations of 1.2 mol% and 3.6 mol%, respectively, relative to the total amount of monomers, and these mixtures were heated at 73°C for approximately 5 hours. Subsequently, an aqueous solution of p-toluenesulfonic acid (2.5% by weight) in an amount equal to 2.0 times the total mass of the monomers was added to the polymerization reaction solution, and after stirring for 12 hours, the solution was separated. The recovered organic layer was poured into a large amount of n-heptane to precipitate the resin, which was then filtered and recovered, yielding a weight-average molecular weight of approximately 5.1 × 10⁶. 3 Resin A4 was obtained with a yield of 61%. This resin A4 has the following structural units. TIFF0007867324000144.tif38154

[0246] <Preparation of the 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]

[0247] <Resin> A1~A4, resin A1~resin A4 <Salt (I)> I-5: Salt represented by formula (I-5) I-13: Salt represented by formula (I-13) I-19: Salt represented by formula (I-19) I-852: Salt represented by formula (I-852) I-1384: Salt represented by formula (I-1384) I-1574: Salt represented by formula (I-1574) <Acid generator> IX-1 IX-2 TIFF0007867324000146.tif40162 <Quencher (C)> C1: Synthesized by the method described in JP-A-2011-39502 TIFF0007867324000147.tif4355 <Solvent> 400 parts of propylene glycol monomethyl ether acetate 100 parts of propylene glycol monomethyl ether 5 parts of γ-butyrolactone

[0248] (Electron beam exposure evaluation of resist composition) A 6-inch silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 °C for 60 seconds. The resist composition was spin-coated onto this silicon wafer so that the film thickness of the composition layer was 0.04 μm. Then, it was prebaked on a direct hot plate at the temperature shown in the "PB" column of Table 2 for 60 seconds to form a composition layer. A contact hole pattern (hole pitch 40 nm / hole diameter 17 nm) was directly drawn on the composition layer formed on the wafer using an electron beam lithography machine ["ELS-F125 125 keV" manufactured by Elionix, Inc.] while changing the exposure dose stepwise. After exposure, post-exposure baking was performed on a hot plate at the temperature shown in the "PEB" column of Table 2 for 60 seconds, and further paddle development was performed with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide for 60 seconds to obtain a resist pattern.

[0249] In the resist pattern obtained after development, the exposure dose at which the formed hole diameter became 17 nm was defined as the effective sensitivity.

[0250] <CD uniformity (CDU) evaluation> In terms of the effective sensitivity, the hole diameter of the pattern formed with a hole diameter of 17 nm was measured 24 times for each hole, and the average value was taken as the average hole diameter of one hole. The standard deviation was obtained using, as the population, the average hole diameters of 400 patterns formed with a hole diameter of 17 nm within the same wafer. The results are shown in Table 3. The numerical values in the table indicate the standard deviation (nm).

Table 3

[0251] (Electron beam exposure evaluation of resist composition: organic solvent development) A 6-inch silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 °C for 60 seconds. The resist composition was spin-coated onto this silicon wafer so that the film thickness of the composition layer was 0.04 μm. Then, it was prebaked on a direct hot plate at the temperature shown in the "PB" column of Table 2 for 60 seconds to form the composition layer. A contact hole pattern (hole pitch 40 nm / hole diameter 17 nm) was directly drawn on the composition layer formed on the wafer using an electron beam lithography machine ["ELS-F125 125 keV" manufactured by Elionix, Inc.] while changing the exposure dose stepwise. After exposure, post-exposure baking was performed on a hot plate at the temperature shown in the "PEB" column of Table 2 for 60 seconds. Next, the composition layer on this silicon wafer was developed at 23 °C for 20 seconds by the dynamic dispense method using butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as the developer to obtain a resist pattern.

[0252] In the resist pattern obtained after development, the exposure dose at which the formed hole diameter became 17 nm was taken as the effective sensitivity.

[0253] <CD uniformity (CDU) evaluation> For effective sensitivity, the hole diameter of a pattern formed with a hole diameter of 17 nm was measured 24 times for each hole, and the average value was taken as the average hole diameter for that hole. The standard deviation was calculated from a population of 400 measurements of the average hole diameter of a pattern formed with a hole diameter of 17 nm on the same wafer. The results are shown in Table 4. The values ​​in the table indicate the standard deviation (nm). [Table 4] Compared to comparative compositions 3 and 4, compositions 8-14 showed smaller standard deviations and better CD uniformity (CDU) evaluation. [Industrial applicability]

[0254] The resist composition containing the salt of the present invention is suitable for semiconductor microfabrication and is extremely useful in industry because it can produce resist patterns with good CD uniformity (CDU).

Claims

1. A salt represented by formula (I). [In formula (I), R １ , R ２ and R ３ Each of these independently represents an iodine atom, a fluorine atom, or a fluorinated alkyl group having 1 to 12 carbon atoms. 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 12 carbon atoms or a hydrocarbon group having 1 to 18 carbon atoms, and -CH 2 - in the haloalkyl group and the hydrocarbon group may be replaced by -O-, -CO-, -S- or -SO ２ -. X １ , X ２ and X ３ This represents an oxygen atom. m1 represents an integer between 0 and 5, and when m1 is 2 or greater, the bases within the parentheses may be the same or different. m² represents an integer between 0 and 4, and when m² is 2 or greater, the bases within the parentheses may be the same or different. m3 represents an integer between 0 and 4, and when m3 is 2 or greater, the bases within the parentheses may be the same or different. m4 represents an integer from 0 to 4, and when m4 is 2 or greater, multiple R ４ They may be identical or different from one another. m5 represents an integer from 0 to 4, and when m5 is 2 or greater, multiple R ５ They may be identical or different from one another. m6 represents an integer from 0 to 4, and when m6 is 2 or greater, multiple R ６ They may be identical or different from one another. m7 represents an integer from 0 to 5, and when m7 is 2 or greater, multiple R ７ They may be identical or different from one another. m8 represents an integer from 0 to 4, and when m8 is 2 or greater, multiple R ８ They may be identical or different from one another. m9 represents an integer from 0 to 4, and when m9 is 2 or greater, multiple R ９ They may be identical or different from one another. However, 0 ≤ m1 + m7 ≤ 5, 0 ≤ m2 + m8 ≤ 4, 0 ≤ m3 + m9 ≤ 4, At least one of m1, m2, and m3 represents an integer greater than or equal to 1. X ４ This is a single bond, -CH 2 -, -O-, -S-, -CO-, -SO-, or -SO ２ It represents -. AI － This represents an organic anion.

2. AI － The salt according to claim 1, wherein the salt is a sulfonate anion, a sulfonylimide anion, or a sulfonylmethide anion.

3. AI － The salt according to claim 1 or 2, wherein is a sulfonate anion, and the sulfonate anion is an anion represented by formula (I-A). [In formula (IA), Q １ and Q ２ Each of these independently represents either a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. L １ This represents a saturated hydrocarbon group having 1 to 24 carbon atoms, and the saturated hydrocarbon group contains -CH ２ The - may be replaced by -O- or -CO-, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxyl group. Y １ This represents a methyl group which may have substituents or an alicyclic hydrocarbon group having 3 to 24 carbon atoms which may have substituents, and the alicyclic hydrocarbon group contains -CH ２ - is -O-, -SO ２ It may be replaced with - or -CO-.

4. An acid generator containing the salt described in any one of claims 1 to 3.

5. A resist composition comprising the acid generator described in claim 4 and a resin having an acid-unstable group.

6. The resist composition according to claim 5, wherein the resin having an acid-unstable group comprises at least one selected from the group consisting of structural units represented by formula (a1-1) and structural units represented by formula (a1-2). [In formulas (a1-1) and (a1-2), L a1 and L a2 These are, independently, -O- or *-O- (CH ２ ) k1 This represents -CO-O-, where k1 is an integer from 1 to 7, and * represents a combination with -CO-. R a4 and R a5 Each of these independently represents a hydrogen atom, a halogen atom, or a C1-C6 alkyl group which may have a halogen atom. R a6 and R a7 Each of these independently represents an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group that is a combination of these. m1 represents an integer between 0 and 14. n1 represents an integer between 0 and 10. n1' represents an integer between 0 and 3.

7. The resist composition according to claim 5 or 6, wherein the resin having an acid-unstable group comprises a structural unit represented by formula (a2-A). [In formula (a2-A), R a50 This represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms that may contain a halogen atom. R a51 This represents a halogen atom, a hydroxyl group, a C1-C6 alkyl group, a C1-C6 alkoxy group, a C2-C12 alkoxyalkyl group, a C2-C12 alkoxyalkoxy group, a C2-C4 alkylcarbonyl group, a C2-C4 alkylcarbonyloxy group, an acryloyloxy group, or a methacryloyloxy group. A a50 This is a single bond or *-X a51 - (A a52 -X a52 ) nｂ - represents -R a50 This represents the bonding site with the carbon atom to which it is bonded. A a52 This represents an alkanediyl group with 1 to 6 carbon atoms. X a51 and X a52 These represent, independently, -O-, -CO-O-, or -O-CO-. nb represents either 0 or 1. mb represents an integer between 0 and 4. If mb is an integer greater than or equal to 2, then multiple R a51 They may be identical or different from one another.

8. The resist composition according to any one of claims 5 to 7, further comprising a salt that generates an acid with a lower acidity than the acid generated from the acid generator.

9. (1) A step of applying the resist composition according to any one of claims 5 to 8 onto a substrate, (2) A step of drying the coated composition to form a composition layer, (3) Exposure step of the composition layer, (4) A step of heating the composition layer after exposure, (5) A step of developing the composition layer after heating, A method for manufacturing a resist pattern that includes [the specified element].

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