Sulfonium salt, chemically amplified resist composition, and patterning method

Abstract

This invention provides an onium salt, a chemically amplified resist composition, and a pattern formation method for use in photolithography using energy rays, which are highly sensitive, have excellent resolution, improve lithography performance such as LWR, CDU, EL, and DOF, and suppress resist pattern deformation. [Solution] A sulfonium salt comprising a sulfonium cation and an aromatic carboxylic acid anion represented by the following formula (1A). TIFF2026076051000453.tif51137

Description

[Technical Field]

[0001] The present invention relates to sulfonium salts, chemically amplified resist compositions, and patterning methods. [Background technology]

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern rules is progressing rapidly. This is because the proliferation of 5G high-speed communication and artificial intelligence (AI) necessitates high-performance devices to process them. As a cutting-edge miniaturization technology, mass production of 5nm node devices is underway using extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm. Furthermore, research using EUV lithography is progressing for next-generation 3nm node and the following-generation 2nm node devices.

[0003] As miniaturization progresses, image blurring due to acid diffusion is becoming a problem. To ensure resolution in fine patterns with dimensions of 45 nm or larger, it has been suggested that controlling acid diffusion is important, in addition to improving the dissolution contrast as has been conventionally proposed (Non-Patent Literature 1). However, since chemically amplified resist compositions increase sensitivity and contrast through acid diffusion, attempting to suppress acid diffusion to the extreme by lowering the post-exposure bake (PEB) temperature or shortening the time results in a significant decrease in sensitivity and contrast.

[0004] The triangle trade-off relationship between sensitivity, resolution, and line width roughness (LWR) is shown. To improve resolution, it is necessary to suppress acid diffusion, but as the acid diffusion distance decreases, sensitivity decreases.

[0005] Adding an acid generator that produces bulky acids is effective in suppressing acid diffusion. Therefore, it has been proposed to include repeating units derived from onium salts having polymerizable unsaturated bonds in the polymer. In this case, the polymer also functions as an acid generator (polymer-bound type acid generator). Patent Document 1 proposes sulfonium salts and iodonium salts having polymerizable unsaturated bonds that generate specific sulfonic acids. Patent Document 2 proposes sulfonium salts in which sulfonic acids are directly linked to the main chain.

[0006] Acid-unstable groups used in (meth)acrylate polymers for ArF resist compositions undergo deprotection reactions when an acid generator that produces sulfonic acid with a fluorine atom substituted at the α-position is used. However, deprotection reactions do not proceed with acid generators that produce sulfonic acid or carboxylic acid without a fluorine atom substituted at the α-position. When a sulfonium salt or iodonium salt that produces sulfonic acid with a fluorine atom substituted at the α-position is mixed with a sulfonium salt or iodonium salt that produces sulfonic acid without a fluorine atom substituted at the α-position, the sulfonium salt or iodonium salt that produces sulfonic acid without a fluorine atom substituted at the α-position undergoes ion exchange with the sulfonic acid with a fluorine atom substituted at the α-position. Since the sulfonic acid with a fluorine atom substituted at the α-position generated by light is converted back to the sulfonium salt or iodonium salt by ion exchange, the sulfonium salt or iodonium salt of sulfonic acid or carboxylic acid without a fluorine atom substituted at the α-position functions as a quencher. A resist composition has been proposed that uses a sulfonium salt or iodonium salt that generates a carboxylic acid as a quencher (Patent Document 3).

[0007] Sulfonium salt type quenchers that generate carboxylic acids have been proposed. For example, sulfonium salts of salicylic acid, β-hydroxycarboxylic acid (Patent Document 4), salicylic acid derivatives (Patent Documents 5 and 6), fluorosalicylic acid (Patent Document 7), hydroxynaphthoic acid (Patent Document 8), salicylic acid with iodine-containing aromatic substituents (Patent Document 9), and salicylic acid with a cyclic acetal structure (Patent Document 10) have been proposed. In particular, salicylic acid is highly effective in suppressing acid diffusion through intramolecular hydrogen bonding between the carboxyl group and the hydroxyl group.

[0008] It has been pointed out that quencher aggregation reduces the dimensional uniformity (CDU) of the resist pattern. By preventing quencher aggregation in the resist film and homogenizing its distribution, it is expected that the dimensional uniformity of the pattern after development will be improved.

[0009] In response to the demand for further miniaturization, a challenge remains: swelling occurs during alkaline development of positive-type resists due to the developer, leading to pattern collapse during fine pattern formation. To address these miniaturization challenges, the development of novel materials for resist compositions is crucial. There is a need for the development of onium salt-type quenchers that exhibit good sensitivity, adequate control of acid diffusion, excellent solvent solubility, and are effective in suppressing pattern collapse. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2006-45311 [Patent Document 2] Japanese Patent Publication No. 2006-178317 [Patent Document 3] Japanese Patent Publication No. 2007-114431 [Patent Document 4] International Publication No. 2018 / 159560 [Patent Document 5] Japanese Patent Publication No. 2020-203984 [Patent Document 6] Japanese Patent Publication No. 2020-91404 [Patent Document 7] Japanese Patent Publication No. 2020-91312 [Patent Document 8] Japanese Patent Publication No. 2019-120760 [Patent Document 9] Japanese Patent Publication No. 2022-77505 [Patent Document 10] International Publication No. 2023 / 189502 [Non-patent literature]

[0011] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) [Overview of the project] [Problems that the invention aims to solve]

[0012] In response to the recent demand for high-resolution resist patterns, conventional resist compositions using sulfonium salt-type acid generators and quenchers have been unable to adequately suppress acid diffusion. As a result, lithography performance such as contrast, LWR, CDU, exposure margin (EL), and depth of field (DOF) has deteriorated. Furthermore, during the formation of fine patterns, swelling can cause pattern collapse.

[0013] The present invention has been made in view of the above circumstances, and aims to provide an onium salt for use in a chemically amplified resist composition, a chemically amplified resist composition, and a pattern formation method that are highly sensitive, have excellent resolution, improve lithography performance such as LWR, CDU, EL, and DOF in photolithography using high-energy rays such as far ultraviolet, electron beam (EB), and EUV, and suppress resist pattern deformation. [Means for solving the problem]

[0014] As a result of diligent research to achieve the above objective, the inventors have discovered that a sulfonium salt comprising a sulfonium cation having a pentafluorosulfanil group and a hydrocarbyloxycarbonyl group and an aromatic carboxylic acid anion having at least one iodine atom on an aromatic ring exhibits excellent solvent solubility, and that a chemically amplified resist composition using this as a quencher exhibits high sensitivity and high contrast, excellent lithography performance such as LWR, CDU, EL, and DOF, is extremely effective in suppressing pattern collapse during fine pattern formation, and contributes to suppressing defects during pattern development using alkaline developers. Based on these findings, the inventors have come to the present invention.

[0015] In other words, the present invention provides the following sulfonium salts, chemically amplified resist compositions, and pattern formation methods. 1. A sulfonium salt comprising a sulfonium cation represented by the following formula (1A) and an aromatic carboxylic acid anion represented by the following formula (1B). [ka] (In the formula, n1 is 0 or 1. n2 is 0, 1 or 2. n3 is 0, 1 or 2. n4 is 0, 1 or 2. However, when n1 is 0, 0 ≤ n2 + n3 + n4 ≤ 5, and when n1 is 1, 0 ≤ n2 + n3 + n4 ≤ 7. n5 is 0 or 1. n6 is 0, 1 or 2. n7 is 0, 1 or 2. n8 is 0, 1 or 2. However, when n5 is 0, 0 ≤ n6 + n7 + n8 ≤ 5, and when n5 is 1, then 0 ≤ n6 + n7 + n8 ≤ 7. n9 is either 0 or 1. n10 is either 0, 1, or 2. n11 is either 0, 1, or 2. n12 is either 0, 1, or 2. However, when n9 is 0, then 0 ≤ n10 + n11 + n12 ≤ 5, and when n9 is 1, then 0 ≤ n10 + n11 + n12 ≤ 7. Also, 1 ≤ n2 + n6 + n10 ≤ 6, and 1 ≤ n3 + n7 + n11 ≤ 6. R 1 , R 2 and R 3 Each of these is an independent hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. When n3 is 2, each R1 may be the same as or different from each other. When n7 is 2, each R 2 may be the same as or different from each other. When n11 is 2, each R 3 may be the same as or different from each other. R 4 、R 5 and R 6 are each independently a halogen atom, a nitro group, a hydroxy group, a carboxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a hetero atom or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a hetero atom. When n4 is 2, each R 4 may be the same as or different from each other, and two Rs 4 may combine with each other to form a ring together with the carbon atom to which they are attached. When n8 is 2, each R 5 may be the same as or different from each other, and two Rs 5 may combine with each other to form a ring together with the carbon atom to which they are attached. When n12 is 2, each R 6 may be the same as or different from each other, and two Rs 6 may combine with each other to form a ring together with the carbon atom to which they are attached. Also, two of the three aromatic rings bonded to S + may combine with each other to form a ring together with the sulfur atom to which they are attached.) [Chemical formula] (In the formula, n11 is 0 or 1. n12 is 1, 2, 3 or 4. n13 is 0, 1 or 2. n14 is 0, 1, 2, 3 or 4. However, when n11 is 0, 2 ≤ n12 + n13 + n14 ≤ 5, and when n11 is 1, 2 ≤ n12 + n13 + n14 ≤ 7.) L A is a single bond, an oxygen atom, a sulfur atom, an ester bond or a carbonate bond. R 7 is L AWhen it is a single bond, it is a hydroxyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom, L A When it is an oxygen atom, a sulfur atom, an ester bond, or a carbonate bond, it is a C1-C20 hydrocarbyl group (excluding acid-unstable groups) or an acid-unstable group, which may also contain a hydrogen atom or a heteroatom. R 8 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than iodine, a nitro group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, or a C1-C20 hydrocarbylthio group which may contain a heteroatom. When n14 is 2, 3, or 4, multiple R 8 These atoms may bond to each other, forming a ring structure with the carbon atoms on the aromatic ring to which they are bonded, and some of the -CH2- atoms in the ring may be substituted with -O- or -S- atoms. 2. A sulfonium salt of 1 wherein the sulfonium cation is represented by the following formula (1A-1). [ka] (In the formula, n2~n4, n6~n8, n10~n12 and R 1 ~R 6 (This is the same as above.) 3. The sulfonium salt of 1 or 2 wherein the aromatic carboxylic acid anion is represented by the following formula (1B-1). [ka] (In the formula, n12~n14, L A , R 7 and R 8 (This is the same as above.) 4.L A However, it is a sulfonium salt of any of 1-3 which is an oxygen atom or an ester bond. 5.L A R is an oxygen atom, a sulfur atom, an ester bond, or a carbonate bond. 3 A sulfonium salt of any of 1-3, where is an acid-unstable group. 6. A sulfonium salt of any of 1 to 5, wherein the acid-unstable group is represented by the following formula (AL-1) or (AL-2). [ka] (In the formula, p1 and p2 are independently 0 or 1. Q1 and q2 are independently 0, 1, 2, 3, or 4.) R L1 , R L2 and R L3 Each of these is independently a C1-C12 hydrocarbyl group, and some of the -CH2- of the hydrocarbyl group may be substituted with -O- or -S-, and if the hydrocarbyl group includes an aromatic ring, some or all of the hydrogen atoms of the aromatic ring may be substituted with a halogen atom, a cyano group, a nitro group, a C1-C4 alkyl group which may contain a halogen atom, or a C1-C4 alkoxy group which may contain a halogen atom. L1 and R L2 However, they may bond to each other and form a ring with the carbon atoms to which they are bonded, and some of the -CH2- in the ring may be substituted with -O- or -S-. R L4 and R L5 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. L6 is a hydrocarbyl group having 1 to 20 carbon atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with -O- or -S-. Also, R L5 and R L6 However, they bond to each other, and the carbon atoms and L that they bond to are bonded together. B Together, they may form a heterocyclic group having 3 to 20 carbon atoms, and some of the -CH2- in the heterocyclic group may be substituted with -O- or -S-. L B It is either -O- or -S-. R La ~R Ld Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom. * indicates a bond with an adjacent oxygen or sulfur atom. A quencher consisting of one of the sulfonium salts from 7.1 to 6. A chemically amplified resist composition containing 8.7 quencher. 9. Eight chemically amplified resist compositions comprising a base polymer containing a polymer having repeating units represented by the following formula (a1). [ka] (In the formula, R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 This consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-OX. 11 - or *-C(=O)-NH-X 11 -The phenylene group or naphthylene group may be substituted with a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. 11 This is a saturated hydrocarbylene group, phenylene group, or naphthylene group having 1 to 10 carbon atoms, and the saturated hydrocarbylene group may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. * represents a bond with a carbon atom of the main chain. AL 1 It is an acid-unstable group. 10. 9 chemically amplified resist compositions in which the polymer comprises repeating units represented by the following formula (a2). [ka] (In the formula, R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 2 The bond is either a single bond or an *-C(=O)-O- bond. The asterisk (*) represents a bond with a carbon atom in the main chain. R 11This is a C1-C20 hydrocarbyl group which may contain a halogen atom, a cyano group, a hydroxyl group, a nitro group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyl group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. When a1 is 2, 3, or 4, each R 11 They may be the same as or different from each other. AL 2 It is an acid-unstable group. a is 0, 1, 2, 3, or 4. 11. 9 or 10 chemically amplified resist compositions, wherein the polymer comprises repeating units represented by the following formula (a3). [ka] (In the formula, b1 is either 0 or 1. When b1 is 0, b2 is 0, 1, 2, or 3, and when b1 is 1, b2 is 0, 1, 2, 3, 4, or 5.) R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 3 The bonds are single bonds, *-C(=O)-O-, or *-C(=O)-NH-. The asterisk (*) represents a bond with a carbon atom in the main chain. X 4 This refers to a single bond, an aliphatic hydrocarbylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining these. X 5 and X 6 Each of these is independently either an oxygen atom or a sulfur atom. However, X 4 and X 6 It is bonded to the carbon atom adjacent to the aromatic ring. R 12 and R 13 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom. 12 and R13 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. R 14 This may include a halogen atom, a hydroxyl group, a cyano group, a nitro group, a C1-C20 hydrocarbyl group which may contain a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom, a C1-C20 hydrocarbylthio group which may contain a heteroatom, or -N(R 14A )(R 14B ) is R 14A and R 14B Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. When b2 is 2 or more, each R 14 They may be the same or different from each other, and there may be multiple R 14 These atoms may bond with each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. 12. A chemically amplified resist composition according to any of 9 to 11, wherein the polymer comprises repeating units represented by the following formula (b1) or (b2). [ka] (In the formula, R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y 1 The bond is either a single bond or an *-C(=O)-O- bond. The asterisk (*) represents a bond with a carbon atom in the main chain. R 21 This is a group having 1 to 20 carbon atoms that includes a hydrogen atom or at least one structure selected from a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic acid anhydride (-C(=O)-OC(=O)-). R 22This is a C1-C20 hydrocarbyl group which may contain a halogen atom, a carboxyl group, a nitro group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyl group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. When c2 is 2, 3, or 4, each R 22 They may be the same as or different from each other. c1 is 1, 2, 3, or 4. c2 is 0, 1, 2, 3, or 4, where 1 ≤ c1 + c2 ≤ 5. 13. A chemically amplified resist composition of any 9 to 12, wherein the polymer comprises at least one selected from repeating units represented by the following formula (c1), repeating units represented by the following formula (c2), repeating units represented by the following formula (c3), repeating units represented by the following formula (c4), and repeating units represented by the following formula (c5). [ka] (In the formula, d1 and d2 are independently 0, 1, 2, or 3. e1 is 0 or 1. e2 is 0, 1, 2, 3, or 4. e3 is 0, 1, 2, 3, or 4. However, when e1 is 0, 0 ≤ e2 + e3 ≤ 4, and when e1 is 1, 0 ≤ e2 + e3 ≤ 6.) R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z 1 This is a phenylene group which may have a single bond or a substituent. Z 2 This is a single bond, **-C(=O)-OZ 21 -,**-C(=O)-NH-Z 21 - or **-OZ 21 - is Z 21is a divalent group obtained by combining an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or these, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 3 is a single bond, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. Z 4 is a single bond, or an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 5 each independently is a single bond, a phenylene group which may have a substituent, a naphthylene group, or *-C(=O)-O-Z 51 -. Z 51 is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the aliphatic hydrocarbylene group may contain a halogen atom, a hydroxy group, an ether bond, an ester bond, or a lactone ring. Z 6 is a single bond, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. Z 7 each independently is a single bond, ***-Z 71 -C(=O)-O-, ***-C(=O)-NH-Z 71 - or ***-O-Z 71 -. is. Z 71 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. Z 8 each independently is a single bond, ****-Z 81 -C(=O)-O-, ****-C(=O)-NH-Z 81 - or ****-O-Z 81 -. Z 81 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. Z 9 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, trifluoromethyl groups, and *-C(=O)-OZ. 91 -, *-C(=O)-N(H)-Z 91 -or *-OZ 91 - is Z 91 This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. * represents a bond with a carbon atom in the main chain. ** represents Z 1 This represents a combination with Z. *** represents Z 6 This represents a combination with Z. **** is Z 7 This represents a combination of two things. L 1 These are single bonds, ether bonds, ester bonds, carbonyl groups, sulfonic acid ester bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Rf 1 and Rf 2 Each of these is independently either a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 3 and Rf 4 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 5 and Rf 6 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. However, all Rf 5 and Rf 6 They cannot simultaneously become hydrogen atoms. Rf 7 This is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated alkylthio group having 1 to 6 carbon atoms. R 31 and R 32 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. Also, R31 and R 32 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. R 33 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than fluorine atoms, or heteroatoms. When e3 is 2, 3, or 4, each R 33 They may be the same or different from each other, and there may be multiple R 33 These atoms may bond with each other to form a ring with the carbon atoms to which they are bonded. M - It is a non-nucleophilic counterion. A + (This is an onium cation.) 14. Furthermore, any of the 8 to 13 chemically amplified resist compositions containing an organic solvent. 15. A chemically amplified resist composition according to any of 8 to 14, further comprising a photoacid generator that generates a strong acid. 16. Furthermore, any of the chemically amplified resist compositions 8 to 15, which include a quencher other than the quencher of 7. 17. Furthermore, any of the chemically amplified resist compositions 8 to 17, comprising a surfactant. A pattern forming method comprising the steps of: forming a resist film on a substrate using any of the chemically amplified resist compositions of 18.8 to 17; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer. 19. A pattern formation method for 18 in which the high-energy beam is KrF excimer laser light, ArF excimer laser light, EB, or EUV with a wavelength of 3 to 15 nm. [Effects of the Invention]

[0016] When pattern formation is performed using a chemically amplified resist composition containing the sulfonium salt of the present invention as a quencher, it is possible to form a resist pattern with high contrast, good sensitivity, excellent lithography performance such as LWR, CDU, EL, and DOF, and suppressed development defects. [Modes for carrying out the invention]

[0017] [Sulfonium salt] The sulfonium salt of the present invention contains a sulfonium cation represented by the following formula (1A). [ka]

[0018] In formula (1A), n1 is either 0 or 1. When n1 is 0, it is a benzene ring, and when n1 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that n1 is a benzene ring with n1 being 0. n2 is either 0, 1, or 2. n3 is either 0, 1, or 2. n4 is either 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that n4 is either 0 or 1. However, when n1 is 0, 0 ≤ n2 + n3 + n4 ≤ 5, and when n1 is 1, 0 ≤ n2 + n3 + n4 ≤ 7.

[0019] In formula (1A), n5 is either 0 or 1. When n5 is 0, it is a benzene ring, and when n5 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that n5 is a benzene ring with n5 being 0. n6 is either 0, 1, or 2. n7 is either 0, 1, or 2. n8 is either 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that n8 is either 0 or 1. However, when n5 is 0, 0 ≤ n6 + n7 + n8 ≤ 5, and when n5 is 1, 0 ≤ n6 + n7 + n8 ≤ 7.

[0020] In formula (1A), n9 is either 0 or 1. When n9 is 0, it is a benzene ring, and when n9 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, a benzene ring with n9 being 0 is preferred. n10 is either 0, 1, or 2. n11 is either 0, 1, or 2. n12 is either 0, 1, or 2. From the viewpoint of raw material procurement, it is preferred that n12 be either 0 or 1. However, when n9 is 0, 0 ≤ n10 + n11 + n12 ≤ 5, and when n9 is 1, 0 ≤ n10 + n11 + n12 ≤ 7.

[0021] In formula (1A), the number of pentafluorosulfanyl groups is 1 ≤ n3 + n7 + n11 ≤ 6, preferably 1 ≤ n3 + n7 + n11 ≤ 3, and more preferably 1 ≤ n3 + n7 + n11 ≤ 2. When the number of pentafluorosulfanyl groups is 2 or more, each pentafluorosulfanyl group may be bonded to the same aromatic ring or to different aromatic rings.

[0022] In formula (1A), the number of hydrocarbyloxycarbonyl groups is 1 ≤ n² + n⁶ + n⁰ ≤ 6, preferably 1 ≤ n² + n⁶ + n⁰ ≤ 3, and more preferably 1 ≤ n² + n⁶ + n⁰ ≤ 2. When the number of hydrocarbyloxycarbonyl groups is 2 or more, each hydrocarbyloxycarbonyl group may be bonded to the same aromatic ring or to different aromatic rings.

[0023] In formula (1A), R 1 , R 2 and R 3 Each of these is independently a C1-C20 hydrocarbyl group which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl groups; cyclopropyl, cyclopentyl, Examples include, but are not limited to, cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; aryl groups having 6 to 30 carbon atoms, such as phenyl, naphthyl, and benzyl; aralkyl groups having 7 to 30 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these.

[0024] Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Specific examples of a hydrocarbyl group containing a heteroatom include, but are not limited to, a fluorine alkyl group such as a trifluoromethyl group, a 1,1,1-trifluoroethyl group, a 1,1,1,3,3,3-hexafluoroisopropyl group, a nonafluorobutyl group, an octafluoropentyl group, and an oxanorbornyl group. The fluorine alkyl group preferably has 1 to 6 carbon atoms.

[0025] When n3 is 2, each R 1 These may be the same or different from each other. When n7 is 2, each R 2 These may be the same or different from each other. When n11 is 2, each R 3 They may be the same as or different from each other.

[0026] In formula (1A), R 4 , R 5 and R 6Each of these is independently a halogen atom, a nitro group, a hydroxyl group, a carboxyl group, a C1-C20 hydrocarbyl group which may contain a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, or a C1-C20 hydrocarbylthio group which may contain a heteroatom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like. The hydrocarbyl portion of the hydrocarbyl group, the hydrocarbyloxy group, and the hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, and 4-methylcyclo Examples include cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as hexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl groups; cyclic unsaturated hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclohexenyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl and naphthyl groups; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these. Of these, aryl groups are preferred.Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When n4 is 2, each R. 4 These may be the same or different from each other. Also, when n4 is 2, the two R 4 However, they may bond to each other and form a ring together with the carbon atoms to which they are bonded. A 5-8 membered ring is preferred for the aforementioned ring. When n8 is 2, each R 5 These may be the same or different from each other. Also, when n8 is 2, the two R 5 These may bond with each other to form a ring with the carbon atoms to which they are bonded. A 5- to 8-membered ring is preferred. When n12 is 2, each R 6 These may be the same or different from each other. Also, when n12 is 2, the two R 6 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. A 5- to 8-membered ring is preferred.

[0027] Also, S + Two of the three aromatic rings bonded to the atom may bond to each other to form a ring with the sulfur atom to which they are bonded. Specific examples of the structure of this ring include those represented by the following formula. [ka] (In the equation, dashed lines represent connections.)

[0028] The sulfonium cation represented by formula (1A) is preferably the one represented by formula (1A-1) below. [ka] (In the formula, n2~n4, n6~n8, n10~n12 and R 1 ~R 6 (This is the same as above.)

[0029] Specific examples of sulfonium cations represented by formula (1A) are listed below, but are not limited to these. In the following formula, Me represents a methyl group. [ka]

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] [ka]

[0036] [ka]

[0037] [ka]

[0038]

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[0039]

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[0040]

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[0041]

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[0050]

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[0060]

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[0061]

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[0063]

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[0064]

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[0065]

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[0066]

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[0067]

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[0068]

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[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] The sulfonium salt of the present invention contains an aromatic carboxylic acid anion represented by the following formula (1B). [ka]

[0077] In formula (1B), n11 is either 0 or 1. When n11 is 0, it is a benzene ring, and when n11 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferably a benzene ring with n11 being 0. n12 is either 1, 2, 3, or 4, but from the viewpoint of raw material procurement, it is preferably 1, 2, or 3, and from the viewpoint of solvent solubility, it is more preferably 1 or 2. n13 is either 0, 1, or 2. n14 is either 0, 1, 2, 3, or 4. However, when n11 is 0, 2 ≤ n12 + n13 + n14 ≤ 5, and when n11 is 1, 2 ≤ n12 + n13 + n14 ≤ 7. n14 is either 0, 1, 2, or 3, and from the viewpoint of raw material procurement, it is more preferably 0, 1, or 2.

[0078] In formula (1B), L A These are single bonds, oxygen atoms, sulfur atoms, ester bonds, or carbonate bonds. (See R below) 3 When it is a hydrogen atom, L A It is preferably an oxygen atom. Also, R, which will be described later. 3 When R is an acid-unstable group, 3 It is preferably an oxygen atom, an ester bond, or a carbonate bond, and more preferably an oxygen atom or an ester bond.

[0079] In formula (1B), R 7 L AWhen it is a single bond, it is a C1-C20 hydrocarbyl group which may contain a hydrogen atom or a heteroatom. The C1-C20 hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 20 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, tert-pentyl group, n-pentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-undecyl group, and n-dodecyl group; cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, norbornylmethyl group, adamantyl group, adamantylmethyl group, and tricyclo[5.2.1.0 2,6 ] Decyl group, tetracyclo[6.2.1.1 3,6 .0 2,7 Examples include: cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as dodecyl groups; alkenyl groups having 2 to 20 carbon atoms, such as vinyl groups, 1-propenyl groups, 2-propenyl groups, butenyl groups, pentenyl groups, and hexenyl groups; alkynyl groups having 2 to 20 carbon atoms, such as ethynyl groups, propynyl groups, butynyl groups, pentynyl groups, and hexynyl groups; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclopentenyl groups and cyclohexenyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl groups, naphthyl groups, and indanyl groups; and aralkyl groups having 7 to 20 carbon atoms, such as benzyl groups, 1-phenylethyl groups, and 2-phenylethyl groups: and groups obtained by combining these. Furthermore, the hydrocarbyl groups may contain heteroatoms, specifically halogen atoms, oxygen atoms, sulfur atoms, etc.

[0080] R 7 L AWhen the atom is an oxygen atom, a sulfur atom, an ester bond, or a carbonate bond, it may contain a hydrogen atom or a heteroatom; in this case, it is a C1-C20 hydrocarbyl group (excluding acid-unstable groups) or an acid-unstable group. Examples of the hydrocarbyl group include those mentioned above, excluding acid-unstable groups.

[0081] The acid-unstable group is preferably one represented by the following formula (AL-1) or (AL-2). [ka] (In the formula, * represents a bond with an adjacent oxygen or sulfur atom.)

[0082] In equations (AL-1) and (AL-2), p1 and p2 are independently 0 or 1. q1 and q2 are independently 0, 1, 2, 3, or 4. A If is an oxygen atom and forms a carbonate bond with the oxygen atom, then p1 or p2 is 1; otherwise, it is preferable that p1 or p2 is 0. Furthermore, when p1 is 1, q1 is preferably 1 or 2, and when p1 is 0, q1 is 0. When p2 is 1, q2 is preferably 1 or 2, and when p2 is 0, q2 is 0.

[0083] In formula (AL-1), R L1 , R L2 and R L3 Each of these is independently a C1-C12 hydrocarbyl group, and some of the -CH2- of the hydrocarbyl group may be substituted with -O- or -S-, and if the hydrocarbyl group includes an aromatic ring, some or all of the hydrogen atoms of the aromatic ring may be substituted with a halogen atom, a cyano group, a nitro group, a C1-C4 alkyl group which may contain a halogen atom, or a C1-C4 alkoxy group which may contain a halogen atom.

[0084] R L1 , R L2 and R L3Hydrocarbyl groups having 1 to 12 carbon atoms, represented by [5.2.1.0], may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 12 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, and n-dodecyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, norbornylmethyl, adamantyl, adamantylmethyl, and tricyclo[5.2.1.0]. 2,6 ] Decyl group, tetracyclo[6.2.1.1 3,6 .0 2,7 Examples include: cyclic saturated hydrocarbyl groups having 3 to 12 carbon atoms, such as the dodecyl group; alkenyl groups having 2 to 12 carbon atoms, such as the vinyl group, 1-propenyl group, 2-propenyl group, butenyl group, pentenyl group, and hexenyl group; alkynyl groups having 2 to 12 carbon atoms, such as the ethynyl group, propynyl group, butynyl group, pentynyl group, and hexynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 12 carbon atoms, such as the cyclopentenyl group and cyclohexenyl group; aryl groups having 6 to 12 carbon atoms, such as the phenyl group, naphthyl group, and indanyl group; and aralkyl groups having 7 to 12 carbon atoms, such as the benzyl group, 1-phenylethyl group, and 2-phenylethyl group: and groups obtained by combining these.

[0085] Also, R L1 and R L2 However, they may bond to each other and form a ring with the carbon atoms to which they are bonded, and some of the -CH2- in the ring may be substituted with -O- or -S-. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a norbornane ring, an adamantane ring, and a tricyclo[5.2.1.0 2,6 ] Decane ring, tetracyclo[6.2.1.1 3,6 .0 2,7Examples include dodecane rings. In addition, some of the -CH2- in the ring may be substituted with -O- or -S-.

[0086] In formula (AL-2), R L4 and R L5 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. L4 and R L5 The hydrocarbyl group, represented by , having 1 to 10 carbon atoms, can be saturated or unsaturated, and can be linear, branched, or cyclic. A specific example is R L1 , R L2 and R L3 Examples of hydrocarbyl groups represented by the formula include those with 1 to 10 carbon atoms.

[0087] In formula (AL-2), R L6 This is a hydrocarbyl group having 1 to 20 carbon atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with -O- or -S-. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and eicosyl group; cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, norbornylmethyl group, adamantyl group, adamantylmethyl group, and tricyclo[5.2.1.0 2,6 ] Decyl group, tetracyclo[6.2.1.1 3,6 .0 2,7] Cyclic saturated hydrocarbyl groups with 3 to 20 carbon atoms, such as dodecyl group; alkenyl groups with 2 to 20 carbon atoms, such as vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group; alkynyl groups with 2 to 20 carbon atoms, such as ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group; cyclic unsaturated aliphatic hydrocarbyl groups with 3 to 20 carbon atoms, such as cyclopentenyl group, cyclohexenyl group, norbornenyl group; phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropyl Examples include aryl groups having 6 to 20 carbon atoms, such as propylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, and tert-butylnaphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl and phenethyl; and groups obtained by combining these. Also, R L5 and R L6 However, they bond to each other, and the carbon atoms and L that they bond to are bonded together. B Together, they may form a heterocyclic group having 3 to 20 carbon atoms, and some of the -CH2- in the heterocyclic group may be substituted with -O- or -S-.

[0088] In formula (AL-2), L B It is either -O- or -S-.

[0089] In equations (AL-1) and (AL-2), R La ~R Ld Each of these is a C1-C20 hydrocarbyl group which may independently contain a hydrogen atom or a heteroatom. The C1-C20 hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 7 Examples of hydrocarbyl groups represented by the same formulas as those exemplified above include, but are not limited to, those shown.

[0090] Specific examples of acid-unstable groups represented by formula (AL-1) are listed below, but are not limited to these. In the following formulas, * represents a bond with an adjacent oxygen or sulfur atom. [ka]

[0091] [ka]

[0092] [ka]

[0093] [ka]

[0094] [ka]

[0095] [ka]

[0096] [ka]

[0097] [ka]

[0098] [ka]

[0099] [ka]

[0100]

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[0101]

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[0102]

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[0103]

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[0104]

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[0105]

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[0106]

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[0107]

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[0108]

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[0109]

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[0110]

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[0111] Specific examples of acid-unstable groups represented by formula (AL-2) are listed below, but are not limited to these. In the following formulas, * represents a bond with an adjacent oxygen or sulfur atom. [ka]

[0112] [ka]

[0113] In formula (1B), R 8 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than iodine, a nitro group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, or a C1-C20 hydrocarbylthio group which may contain a heteroatom. Examples of halogen atoms other than iodine include fluorine, chlorine, and bromine atoms, but fluorine is preferred. The C1-C20 hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 7 Examples of hydrocarbyl groups represented by the formula are similar to those exemplified. Furthermore, the hydrocarbyl group may contain heteroatoms, specifically halogen atoms, oxygen atoms, sulfur atoms, etc.

[0114] Also, when n14 is 2, 3, or 4, multiple R 8 These may bond to each other, forming a ring structure with the carbon atoms on the aromatic ring to which they are bonded, and some of the -CH2- in the ring may be substituted with -O- or -S-. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a norbornane ring, an adamantane ring, and a tricyclo[5.2.1.02,6 ] Decane ring, tetracyclo[6.2.1.1 3,6 .0 2,7 Examples include dodecane rings. In addition, some of the -CH2- in the ring may be substituted with -O- or -S-.

[0115] The aromatic carboxylic acid anion represented by formula (1B) is preferably the one represented by formula (1B-1) below. [ka] (In the formula, n12~n14, L A , R 7 and R 8 (This is the same as above.)

[0116] Specific examples of aromatic carboxylic acid anions represented by formula (1B) are listed below, but are not limited to these. [ka]

[0117] [ka]

[0118] [ka]

[0119] [ka]

[0120] [ka]

[0121] [ka]

[0122]

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[0123]

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[0124]

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[0125]

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[0126]

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[0127]

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[0128]

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[0207] [ka]

[0208] [ka]

[0209] [ka]

[0210] [ka]

[0211] [ka]

[0212] [ka]

[0213] [ka]

[0214] [ka]

[0215] [ka]

[0216] Specific examples of the sulfonium salt of the present invention include any combination of the anion and cation described above.

[0217] The sulfonium salts of the present invention can be synthesized, for example, by a method similar to that of the onium salt described in Japanese Patent Publication No. 2020-91312, but are not limited thereto.

[0218] The structural features of the sulfonium salt of the present invention include the fact that it consists of a sulfonium cation having a pentafluorosulfanil group and a hydrocarbyloxycarbonyl group, and an aromatic carboxylic acid anion having an iodine atom. The aromatic carboxylic acid anion containing an iodine atom exhibits very high absorption of EUV by the iodine atom, particularly in EUV lithography at a wavelength of 13.5 nm, thus generating secondary electrons from the iodine atom during exposure. Furthermore, the iodine atom has a moderate dissolution inhibitory ability, suppressing pattern collapse in unexposed areas, especially with respect to alkaline developers. The pentafluorosulfanil group bonded to the aromatic ring of the sulfonium cation is known to be a strong electron-withdrawing group. From this, it is thought that the energy level of the LUMO in frontier orbital theory is lowered. Therefore, it becomes easier to accept the generated secondary electrons, promoting the decomposition of the cation, and these synergistic effects result in increased sensitivity. The hydrocarbyloxycarbonyl group substituted on the aromatic ring of the sulfonium cation has a lone pair of electrons derived from the ester bond, and is therefore expected to function as an acid diffusion inhibitor by interacting with the proton of the generated acid. Furthermore, since the hydrocarbyloxycarbonyl group has electron-withdrawing properties, albeit not to the same extent as the pentafluorosulfanil group, it is expected that the energy level of the LUMO in frontier orbital theory will decrease. In addition, since the hydrocarbyloxycarbonyl group is hydrolyzable to alkaline developers, the decomposition products of the cation in the exposed area will show affinity to the alkaline developer, thereby suppressing development residue. Also, if the anion has an acid-unstable group, the deprotection reaction of the acid-unstable group by the generated acid will proceed, and it is expected that the contrast will be improved and the sensitivity will be increased due to the change in solubility. In the exposed area of ​​a positive resist, the higher the affinity to the alkaline developer, the lower the risk of development defects. Furthermore, since the sulfonium salt of the present invention has an aromatic carboxylic acid anion, it is relatively basic and effectively traps the strong acid generated from the photoacid generator.Due to these synergistic effects, when using the sulfonium salt of the present invention, it is possible to form patterns that are highly resistant to pattern deformation, exhibit high dissolution contrast, excellent lithography performance such as LWR for line patterns and CDU for hole patterns, and are therefore suitable as a material for positive-type resist compositions.

[0219] The sulfonium salt of the present invention can be suitably used as a quencher. In the present invention, a quencher is a material that traps the strong acid generated from the photoacid generator to prevent diffusion to unexposed areas and form a desired pattern. A photoacid generator is a compound that generates a strong acid upon irradiation with high-energy rays, and a strong acid is a compound that has sufficient acidity to cause a deprotection reaction of an acid-unstable group. In the case of the aromatic carboxylic acid, if the acid-unstable group is a tertiary ester or tertiary ether, it does not have enough acidity to cause a deprotection reaction. Therefore, as described later, it is effective to separately add a photoacid generator that generates a sulfonic acid, imido acid, or methidic acid with a fluorinated α-position, which is a strong acid that causes a deprotection reaction of an acid-unstable group. The photoacid generator that generates a sulfonic acid, imido acid, or methidic acid with a fluorinated α-position may be an additive type, or it may be a polymer-bound type bonded to the base polymer.

[0220] When a mixture of a sulfonium salt that generates the aromatic carboxylic acid and a photoacid generator that generates the superacid perfluoroalkyl sulfonic acid is irradiated with light, both the aromatic carboxylic acid and the perfluoroalkyl sulfonic acid are generated. Since the photoacid generator is not completely decomposed, undecomposed photoacid generator remains nearby. When the sulfonium salt that generates the aromatic carboxylic acid and the perfluoroalkyl sulfonic acid coexist, the perfluoroalkyl sulfonic acid first undergoes ion exchange with the sulfonium salt that generates the aromatic carboxylic acid, generating perfluoroalkyl sulfonic acid sulfonium salt, and releasing the aromatic carboxylic acid. This is because the perfluoroalkyl sulfonate, which has higher acid strength, is more stable. On the other hand, ion exchange does not occur even if perfluoroalkyl sulfonic acid sulfonium salt and the aromatic carboxylic acid are present. Similar ion exchange occurs not only with perfluoroalkyl sulfonic acid, but also with arene sulfonic acid, alkyl sulfonic acid, imido acid, methidic acid, etc., which have higher acid strength than the aromatic carboxylic acid generated from the sulfonium salt of the present invention.

[0221] [Chemically amplified resist composition] [(A) Quencher] The chemical amplification resist composition of the present invention contains as an essential component a quencher comprising a sulfonium salt consisting of a sulfonium cation represented by formula (1A) and an aromatic carboxylic acid anion represented by formula (1B).

[0222] In the chemically amplified resist composition of the present invention, the content of (A) quencher is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 30 parts by mass, relative to 80 parts by mass of the base polymer described later. When the content of (A) quencher is within the above range, the sensitivity and resolution are good, and there is no risk of foreign matter problems occurring after development or peeling of the resist film, so it is preferable. (A) quencher may be used alone or in combination of two or more types.

[0223] [(B) Base polymer] The chemically amplified resist composition of the present invention may contain a base polymer as component (B). The (B) base polymer is preferably a polymer containing a repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1). [ka]

[0224] In formula (a1), R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0225] In formula (a1), X 1 This consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-OX. 11 - or *-C(=O)-NH-X 11 -The phenylene group or naphthylene group may be substituted with a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. 11 This is a saturated hydrocarbylene group, phenylene group, or naphthylene group having 1 to 10 carbon atoms, and the saturated hydrocarbylene group may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. * represents a bond with a carbon atom of the main chain.

[0226] In formula (a1), AL 1 This is an acid-unstable group. Specific examples of the acid-unstable group include those described in Japanese Patent Publication No. 2013-80033 and Japanese Patent Publication No. 2013-83821.

[0227] Typical examples of the acid-unstable groups include those represented by the following formulas (AL-3) to (AL-5). [ka] (In the equation, dashed lines represent connections.)

[0228] In equations (AL-3) and (AL-4), R L11 and R L12 Each of these is independently a hydrocarbyl group having 1 to 40 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably one having 1 to 20 carbon atoms.

[0229] In formula (AL-3), k is an integer between 0 and 10, preferably 1, 2, 3, 4, or 5.

[0230] In formula (AL-4), R L13 and R L14 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, or fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Also, R L12 , R L13 and R L14 Any two of these may bond with each other to form a ring having 3 to 20 carbon atoms, together with the carbon atom to which they are bonded, or a carbon atom and an oxygen atom. The ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0231] In formula (AL-5), R L15 , R L16 and R L17 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Also, R L15 , R L16 and R L17 Any two of these may bond with each other to form a ring with 3 to 20 carbon atoms. The ring is preferably a ring with 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0232] Other specific examples of the aforementioned acid-unstable groups include those described in paragraphs

[0064] to

[0068] of Japanese Patent Publication No. 2023-123222 and those described in paragraphs

[0013] to

[0014] of Japanese Patent Publication No. 7492842. These reactions are driven by the formation of conjugated olefins or acrylic acid ester derivatives after the acid elimination reaction.

[0233] Specific examples of repeating unit a1 are shown below, but are not limited to these. Note that in the following formula, R A and AL 1 This is the same as described above. [ka]

[0234] [ka]

[0235] [ka]

[0236] [ka]

[0237] [ka]

[0238] [ka]

[0239] [ka]

[0240] The polymer may contain repeating units represented by the following formula (a2) (hereinafter also referred to as repeating unit a2). [ka]

[0241] In formula (a2), R A X is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 2 The bond is either a single bond or *-C(=O)-O-. * represents a bond with a carbon atom in the main chain. 11 This is a C1-C20 hydrocarbyl group which may contain a halogen atom, a cyano group, a hydroxyl group, a nitro group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyl group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. 2 This is an acid-unstable group. Specific examples of the aforementioned acid-unstable group include AL. 1 Examples of acid-unstable groups represented by the formula are similar to those exemplified. a is 0, 1, 2, 3, or 4, preferably 0 or 1. When a is 2, 3, or 4, each R 11 They may be the same as or different from each other.

[0242] Specific examples of repeating unit a2 are shown below, but are not limited to these. Note that in the following formula, R A and AL 2 This is the same as described above. [ka]

[0243] [ka]

[0244] [ka]

[0245] The polymer may contain repeating units represented by the following formula (a3) ​​(hereinafter also referred to as repeating unit a3). [ka]

[0246] In formula (a3), b1 is either 0 or 1. When b1 is 0, it is a benzene ring, and when b1 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that b1 is a benzene ring with a value of 0. When b1 is 0, b2 is 0, 1, 2, or 3, and when b1 is 1, it is 0, 1, 2, 3, 4, or 5. From the viewpoint of raw material procurement, it is preferable that b2 is 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0247] In formula (a3), R A R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. A Preferably, it is a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0248] In formula (a3), X 3 The bond is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. The asterisk (*) represents a bond with a carbon atom of the main chain. Of these, a single bond or *-C(=O)-O- is preferred, and a single bond is even more preferred.

[0249] In formula (a3), X 4 These are single bonds, aliphatic hydrocarbylene groups having 1 to 4 carbon atoms, carbonyl groups, sulfonyl groups, or groups obtained in combination thereof. Of these, single bonds, carbonyl groups, or sulfonyl groups are preferred from the viewpoint of raw material procurement, and single bonds or carbonyl groups are more preferred from the viewpoint of polar groups generated after the reaction.

[0250] In formula (a3), X5 and X 6 Each of these is independently either an oxygen atom or a sulfur atom. However, X 4 and X 6 It is bonded to the carbon atom adjacent to the aromatic ring. 5 and X 6 They may be the same or different from each other, but from the standpoint of reactivity, X 5 and X 6 Preferably, both are oxygen atoms.

[0251] In formula (a3), R 12 and R 13Each of these is a C1-C20 hydrocarbyl group which may independently contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, and 4-methylcyclo Examples include cyclic saturated hydrocarbyl groups with 3 to 20 carbon atoms, such as hexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl groups; cyclic unsaturated hydrocarbyl groups with 3 to 20 carbon atoms, such as cyclohexenyl groups; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl groups; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, the material may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0252] Also, R 12 and R 13These may bond with each other to form a ring with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, and so on. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, the ring may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and so on.

[0253] In formula (a3), R 14 This may include a halogen atom, a hydroxyl group, a cyano group, a nitro group, a C1-C20 hydrocarbyl group which may contain a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom, a C1-C20 hydrocarbylthio group which may contain a heteroatom, or -N(R 14A )(R 14B ) is R 14A and R 14B Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and more preferably a fluorine atom or an iodine atom. The hydrocarbyl portion of the hydrocarbyl group and the hydrocarbyloxy group, hydrocarbyloxycarbonyl group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 12 and R 13Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, and nitrogen atoms, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When b2 is 2 or more, each R 14 They may be the same as or different from each other.

[0254] Also, when b2 is 2 or more, multiple R 14 However, they may bond with each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornane rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., and as a result, the ring may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0255] Specific examples of repeating unit a3 are shown below, but are not limited to these. Note that in the following formula, R A The same as described above, where Me is a methyl group. Furthermore, the bonding positions of the various substituents on the aromatic ring may be interchanged. [ka]

[0256]

change

[0257]

change

[0258]

change

[0259]

change

[0260]

change

[0261]

change

[0262]

change

[0263]

change

[0264]

change

[0265]

change

[0266]

change

[0267]

change

[0268]

change

[0269]

change

[0270]

change

[0271]

change

[0272]

change

[0273]

change

[0274]

change

[0275]

change

[0276]

change

[0277]

change

[0278]

change

[0279]

change

[0280]

change

[0281]

change

[0282]

change

[0283]

change

[0284]

change

[0285]

change

[0286]

change

[0287]

change

[0288]

change

[0289]

change

[0290]

change

[0291]

change

[0292]

change

[0293]

change

[0294]

change

[0295]

change

[0296]

change

[0297]

change

[0298] [ka]

[0299] [ka]

[0300] [ka]

[0301] [ka]

[0302] [ka]

[0303] [ka]

[0304] [ka]

[0305] The polymer preferably contains a repeating unit represented by the following formula (b1) (hereinafter also referred to as repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit b2). [ka]

[0306] In equations (b1) and (b2), R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 The bond is either a single bond or *-C(=O)-O-. * represents a bond with a carbon atom in the main chain.21 R is a group having 1 to 20 carbon atoms that includes a hydrogen atom or at least one structure selected from a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic acid anhydride (-C(=O)-OC(=O)-). 22 This is a C1-C20 hydrocarbyl group which may contain a halogen atom, a carboxyl group, a nitro group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyl group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. When c2 is 2, 3, or 4, each R 22 c1 and c2 may be the same or different from each other. c1 is 1, 2, 3, or 4. c2 is 0, 1, 2, 3, or 4, where 1 ≤ c1 + c2 ≤ 5.

[0307] Specific examples of repeating unit b1 are shown below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0308] [ka]

[0309] [ka]

[0310] [ka]

[0311]

change

[0312]

change

[0313]

change

[0314]

change

[0315]

change

[0316]

change

[0317]

change

[0318]

change

[0319]

change

[0320]

change

[0321]

change

[0322] [ka]

[0323] Specific examples of repeating unit b2 are shown below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0324] [ka]

[0325] [ka]

[0326] [ka]

[0327] [ka]

[0328] As for the repeating unit b1 or b2, in ArF lithography, it is particularly preferable to have a lactone ring as a polar group, and in KrF lithography, EB lithography, and EUV lithography, it is preferable to have a phenol moiety.

[0329] The polymer may contain at least one selected from the following repeating units: a repeating unit represented by formula (c1) (hereinafter also referred to as repeating unit c1), a repeating unit represented by formula (c2) (hereinafter also referred to as repeating unit c2), a repeating unit represented by formula (c3) (hereinafter also referred to as repeating unit c3), a repeating unit represented by formula (c4) (hereinafter also referred to as repeating unit c4), and a repeating unit represented by formula (c5) (hereinafter also referred to as repeating unit c5). [ka]

[0330] In formulas (c1) to (c5), R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 This is a phenylene group which may have a single bond or a substituent. 2 This is a single bond, **-C(=O)-OZ 21 -,**-C(=O)-NH-Z 21 - or **-OZ 21 - is Z 21 This is a divalent group obtained by combining an aliphatic hydrocarbylene group, a phenylene group, or a combination thereof, having 1 to 6 carbon atoms, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 3 These are single bonds, ether bonds, ester bonds, amide bonds, sulfonic acid ester bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. 4 This is a single bond, or a divalent group obtained by combining an aliphatic hydrocarbylene group, a phenylene group, or a combination thereof, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 5 Each of these independently comprises a single bond, a phenylene group which may have substituents, a naphthylene group which may have substituents, or a *-C(=O)-OZ 51 - is Z 51This is an aliphatic hydrocarbylene group, a phenylene group, or a naphthylene group having 1 to 10 carbon atoms, and the aliphatic hydrocarbylene group may contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or a lactone ring. 6 These are single bonds, ether bonds, ester bonds, amide bonds, sulfonic acid ester bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. 7 Each of these is independently a single bond, ***-Z 71 -C(=O)-O-, ***-C(=O)-NH-Z 71 -or ***-OZ 71 - is. is. Z 71 This is a hydrocarbylene group having 1 to 20 carbon atoms, which may contain heteroatoms. 8 These are, independently, single bonds, ****-Z 81 -C(=O)-O-,****-C(=O)-NH-Z 81 -or ****-OZ 81 - is Z 81 This is a hydrocarbylene group having 1 to 20 carbon atoms, which may contain heteroatoms. 9 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, trifluoromethyl groups, and *-C(=O)-OZ. 91 -, *-C(=O)-N(H)-Z 91 -or *-OZ 91 - is Z 91 This is a phenylene group substituted with an aliphatic hydrocarbylene group, phenylene group, fluorinated phenylene group, or trifluoromethyl group having 1 to 6 carbon atoms, and may contain a carbonyl group, ester bond, ether bond, or hydroxyl group. * represents a bond with a carbon atom of the main chain. ** represents Z 1 This represents a combination with Z. *** represents Z 6 This represents a combination with Z. **** is Z 7 This represents a combination of two things.

[0331] Z 21 , Z 51 and Z 91The aliphatic hydrocarbylene group represented by can be linear, branched, or cyclic, and specific examples include methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, propane-2,2-diyl group, butane-1,1-diyl group, butane-1,2-diyl group, butane-1,3-diyl group, butane- Examples include alkanediyl groups such as 2,3-diyl group, butane-1,4-diyl group, 1,1-dimethylethane-1,2-diyl group, pentane-1,5-diyl group, 2-methylbutane-1,2-diyl group, and hexane-1,6-diyl group; cycloalkanediyl groups such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, and cyclohexanediyl group; and groups obtained by combining these.

[0332] Z 71 and Z 81 The hydrocarbylene group, which may contain a heteroatom represented by , may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples are listed below, but are not limited to these. [ka] (In the equation, dashed lines represent connections.)

[0333] In formula (c1), R 31 and R 32Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups; C3-C20 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; C2-C20 alkenyl groups such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl groups; C3-C20 cyclic unsaturated hydrocarbyl groups such as cyclohexenyl; C6-C20 aryl groups such as phenyl, naphthyl, and thienyl groups; C7-C20 aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these, but aryl groups are preferred. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0334] Also, R 31 and R 32 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. Specific examples of such a ring include those represented by the following formula. [ka] (In the formula, the dashed line represents Z 4 (This is a combination of the two.)

[0335] Specific examples of cations of repeating unit c1 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0336] [ka]

[0337] [ka]

[0338] [ka]

[0339] [ka]

[0340] [ka]

[0341] [ka]

[0342] [ka]

[0343] [ka]

[0344] [ka]

[0345] In formula (c1), M - The first is a non-nucleophilic counterion. Preferred non-nucleophilic counterions include halide ions, sulfonate anions, imidate anions, and methidate anions. Specific examples of halide ions include chloride ions and bromide ions. Specific examples of sulfonate anions (sulfonate ions) include fluoroalkyl sulfonate ions such as triflate ions, 1,1,1-trifluoroethanesulfonate ions, and nonafluorobutanesulfonate ions; aryl sulfonate ions such as tosylate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, and 1,2,3,4,5-pentafluorobenzenesulfonate ions; and alkyl sulfonate ions such as mesylate ions and butanesulfonate ions. Specific examples of imidate anions (imide ions) include bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, and bis(perfluorobutylsulfonyl)imide ions. Specific examples of the methidate anion (methide ion) mentioned above include tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0346] Other examples of the aforementioned non-nucleophilic counterions include anions represented by any of the following formulas (c1-1) to (c1-4). [ka]

[0347] In formula (c1-1), R fa R is a C1-C40 hydrocarbyl group which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (c1-1-1) described later. fa1Examples of hydrocarbyl groups represented by the symbol shown are similar to those exemplified.

[0348] The anion represented by formula (c1-1) is preferably the one represented by the following formula (c1-1-1). [ka]

[0349] In formula (c1-1-1), Q 1 and Q 2 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, but to improve solvent solubility, it is preferable that at least one of them is a trifluoromethyl group. m is 0, 1, 2, 3, or 4, but it is particularly preferable that it is 1. R fa1 This is a hydrocarbyl group having 1 to 35 carbon atoms, which may contain heteroatoms. The heteroatoms are preferably oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc., with oxygen atoms being more preferred. From the viewpoint of obtaining high resolution in fine pattern formation, the hydrocarbyl group having 6 to 30 carbon atoms is particularly preferred.

[0350] In formula (c1-1-1), R fa1The C1-C35 hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C35 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and eicosyl; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornyl Examples include cyclic saturated hydrocarbyl groups with 3 to 35 carbon atoms, such as nylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated aliphatic hydrocarbyl groups with 2 to 35 carbon atoms, such as 2-propenyl and 3-cyclohexenyl; aryl groups with 6 to 35 carbon atoms, such as phenyl, 1-naphthyl, 2-naphthyl, and 9-fluorenyl; aralkyl groups with 7 to 35 carbon atoms, such as benzyl and diphenylmethyl; and groups obtained by combining these.

[0351] Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Specific examples of hydrocarbyl groups containing heteroatoms include tetrahydrofuryl group, methoxymethyl group, ethoxymethyl group, methylthiomethyl group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy)methyl group, acetoxymethyl group, 2-carboxy-1-cyclohexyl group, 2-oxopropyl group, 4-oxo-1-adamantyl group, and 3-oxocyclohexyl group.

[0352] In formula (c1-1-1), L a1 The bond can be a single bond, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, or a carbamate bond, but from a synthetic viewpoint, an ether bond or an ester bond is preferred, and an ester bond is even more preferred.

[0353] Specific examples of anions represented by formula (c1-1) are listed below, but are not limited to these. Note that in the formula below, Q 1 This is the same as above, and Ac is an acetyl group. [ka]

[0354] [ka]

[0355] [ka]

[0356] [ka]

[0357] [ka]

[0358] [ka]

[0359] [ka]

[0360] [ka]

[0361] [ka]

[0362] [ka]

[0363] [ka]

[0364] [ka]

[0365] In formula (c1-2), R fb1 and R fb2 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may independently contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (c1-1-1). fa1 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fb1 and R fb2 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 However, they bond to each other and the group to which they bond (-CF2-SO2-N - It may form a ring with -SO2-CF2-), in which case R fb1 and R fb2 The groups obtained by the bonding of these groups are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0366] In formula (c1-3), R fc1 , R fc2 and R fc3Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may independently contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (c1-1-1). fa1 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fc1 , R fc2 and R fc3 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 However, they bond to each other and the group to which they bond (-CF2-SO2-C - It may form a ring with -SO2-CF2-), in which case R fc1 and R fc2 The groups obtained by the bonding of these groups are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0367] In formula (c1-4), R fd R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (c1-1-1). fa1 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0368] Specific examples of anions represented by formula (c1-4) are listed below, but are not limited to these. [ka]

[0369] [ka]

[0370] Further examples of the aforementioned non-nucleophilic counterions include anions having an aromatic ring substituted with an iodine or bromine atom. Specific examples of such anions include those represented by the following formulas (c1-5). [ka]

[0371] In equation (c1-5), x1 is 1, 2, or 3. y1 is 1, 2, 3, 4, or 5. z1 is 0, 1, 2, or 3, where 1 ≤ y1 + z1 ≤ 5. y1 is preferably 1, 2, or 3, more preferably 2 or 3. z1 is preferably 0, 1, or 2.

[0372] In formula (c1-5), X BI is an iodine atom or a bromine atom. When x1 and / or y1 are 2 or more, each X BI They may be the same as or different from each other.

[0373] In formula (c1-5), L 11 This is a saturated hydrocarbylene group having 1 to 6 carbon atoms, which may contain a single bond, an ether bond, or an ester bond, or an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0374] In formula (c1-5), L 12 When x1 is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms, and when x1 is 2 or 3, it is a (x1+1) valent linking group having 1 to 20 carbon atoms, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0375] In formula (c1-5), R feThis may include a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group, or an ether bond, and may contain a C1-C20 hydrocarbyl group, a C1-C20 hydrocarbyloxy group, a C2-C20 hydrocarbylcarbonyl group, a C2-C20 hydrocarbyloxycarbonyl group, a C2-C20 hydrocarbylcarbonyloxy group, or a C1-C20 hydrocarbylsulfonyloxy group, or -N(R feA )(R feB ), -N(R feC )-C(=O)-R feD Or -N(R feC )-C(=O)-OR feD That is. R feA and R feB Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. feC R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. feD This is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When x1 and / or z1 is 2 or more, each R fe They may be the same as or different from each other.

[0376] Of these, R feExamples include hydroxyl groups, -N(R feC )-C(=O)-R feD , -N(R feC )-C(=O)-OR feD Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc. are preferred.

[0377] In formula (c1-5), Rf 11 ~Rf 14 Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of these is either a fluorine atom or a trifluoromethyl group. Also, Rf 11 and Rf 12 These may combine to form a carbonyl group. In particular, Rf 13 and Rf 14 It is preferable that both are fluorine atoms.

[0378] Specific examples of anions represented by formula (c1-5) are listed below, but are not limited to these. Note that in the following formula, X BI This is the same as described above. [ka]

[0379] [ka]

[0380] [ka]

[0381] [ka]

[0382] [ka]

[0383]

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[0384]

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[0385]

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[0386]

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[0387]

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[0388]

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[0389]

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[0390]

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[0391]

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[0392]

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[0393]

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[0394]

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[0395]

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[0396]

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[0397]

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[0398]

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[0399]

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[0400]

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[0401]

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[0402] As the non-nucleophilic counterions, the following can also be used: a fluorobenzenesulfonic acid anion bonded to an aromatic group containing an iodine atom, as described in Japanese Patent No. 6648726; an anion having a mechanism for decomposition by acid, as described in International Publication No. 2021 / 200056 and Japanese Patent Application Publication No. 2021-70692; an anion having a cyclic ether group, as described in Japanese Patent Application Publication No. 2018-180525 and Japanese Patent Application Publication No. 2021-35935; and an anion described in Japanese Patent Application Publication No. 2018-92159.

[0403] As the non-nucleophilic counterions, anions of bulky benzenesulfonic acid derivatives that do not contain fluorine atoms, as described in Japanese Patent Publication No. 2006-276759, Japanese Patent Publication No. 2015-117200, Japanese Patent Publication No. 2016-65016, and Japanese Patent Publication No. 2019-202974, as well as benzenesulfonic acid anions or alkylsulfonic acid anions that do not contain fluorine atoms bonded to an aromatic group containing an iodine atom, as described in Japanese Patent No. 6645464.

[0404] As the non-nucleophilic counterion, other options include the bissulfonic acid anion described in Japanese Patent Publication No. 2015-206932, the sulfonamide or sulfonimide anion described in International Publication No. 2020 / 158366, which has a sulfonic acid on one end and a different sulfonamide or sulfonimide on the other, and the sulfonate anion described in Japanese Patent Publication No. 2015-24989.

[0405] In formulas (c2) and (c3), d1 and d2 are independently 0, 1, 2, or 3, but 1 is preferred.

[0406] In equation (c4), e1 is either 0 or 1. e2 is either 0, 1, 2, 3, or 4. e3 is either 0, 1, 2, 3, or 4. However, when e1 is 0, 0 ≤ e2 + e3 ≤ 4, and when e1 is 1, 0 ≤ e2 + e3 ≤ 6.

[0407] In equations (c2), (c3), and (c4), L 1These are single bonds, ether bonds, ester bonds, carbonyl groups, sulfonic acid ester bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Of these, ether bonds, ester bonds, and carbonyl groups are preferred from a synthetic viewpoint, and ester bonds and carbonyl groups are more preferred.

[0408] In formula (c2), Rf 1 and Rf 2 Each of these is independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Of these, Rf 1 and Rf 2 To increase the acid strength of the generated acid, it is preferable that all atoms be fluorine atoms. Rf 3 and Rf 4 These are, independently, a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Of these, Rf is used to improve solvent solubility. 3 and Rf 4 At least one of them is preferably a trifluoromethyl group.

[0409] In formula (c3), Rf 5 and Rf 6 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. However, all Rf 5 and Rf 6 These cannot simultaneously become hydrogen atoms. Of these, Rf 5 and Rf 6 At least one of them is preferably a trifluoromethyl group.

[0410] In formula (c4), Rf 7 Rf is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated alkylthio group having 1 to 6 carbon atoms. 7Preferably, the Rf is a fluorine atom, a trifluoromethyl group, a difluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, a trifluoromethylthio group, or a difluoromethylthio group, and more preferably a fluorine atom, a trifluoromethyl group, or a trifluoromethoxy group. When e2 is 2, 3, or 4, each Rf 7 They may be the same as or different from each other.

[0411] In formula (c4), R 33 R is a C1-C20 hydrocarbyl group which may contain halogen atoms other than fluorine atoms, or heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. For example, in the explanation of formula (1A), R 1 ~R 3 Examples of hydrocarbyl groups represented by the same as those exemplified are, but are not limited to, those shown. Also, when e3 is 2, 3, or 4, each R 33 They may be the same as or different from each other.

[0412] Also, when e3 is 2, 3, or 4, multiple R 33 These elements may bond with each other to form a ring with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornane rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, the ring may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0413] Specific examples of anions with repeating unit c2 are shown below, but are not limited to these. Note that in the following formula, R A The same as above, and Me is a methyl group. [ka]

[0414] [ka]

[0415] [ka]

[0416] [ka]

[0417] [ka]

[0418] [ka]

[0419] [ka]

[0420] [ka]

[0421] [ka]

[0422] [ka]

[0423] [ka]

[0424] [ka]

[0425] [ka]

[0426] Specific examples of anions with repeating unit c3 are shown below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0427] [ka]

[0428] [ka]

[0429] [ka]

[0430] [ka]

[0431] [ka]

[0432] [ka]

[0433] [ka]

[0434] [ka]

[0435] [ka]

[0436] [ka]

[0437] Specific examples of anions with repeating unit c4 are shown below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0438] [ka]

[0439] [ka]

[0440] [ka]

[0441] [ka]

[0442]

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[0443]

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[0444]

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[0445]

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[0446]

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[0447]

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[0448]

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[0449]

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[0450]

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[0451]

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[0452]

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[0453] [ka]

[0454] Specific examples of anions with repeating unit c5 are shown below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0455] In formulas (c2) to (c5), A + This is an onium cation. Examples of the onium cation include sulfonium cations, iodonium cations, ammonium cations, etc., but sulfonium cations and iodonium cations are preferred. Specific examples of the sulfonium cation include, but are not limited to, those exemplified as specific examples of sulfonium cations represented by formula (1A), those described in paragraphs

[0102] to

[0125] of Japanese Patent Application Publication No. 2024-3744, those described in paragraphs

[0044] to

[0049] of International Publication No. 2024 / 128017, and those described in paragraphs

[0035] to

[0046] of Japanese Patent No. 7491173.

[0456] Furthermore, a sulfonium cation represented by the following formula (sulfo-1) is also preferred as the sulfonium cation. [ka]

[0457] In formula (sulfo-1), f1 is either 0 or 1. When f1 is 0, it is a benzene ring, and when f1 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, a benzene ring with f1 being 0 is preferred. f2 is either 0 or 1. When f2 is 0, it is a benzene ring, and when f2 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, a benzene ring with f1 being 0 is preferred. f3 is either 0 or 1. When f3 is 0, it is a benzene ring, and when f3 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, a benzene ring with f3 being 0 is preferred.

[0458] In formula (sulfo-1), f4 is 0, 1, 2, 3, or 4. The more iodine atoms in the cation structure there are, the higher the absorption, especially for EUV. However, this also leads to poor solvent solubility and concerns about precipitation in the resist composition. Therefore, f4 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0459] In formula (sulfo-1), f5 is 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, f5 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. f6 is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material procurement, f6 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. f7 is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material procurement, f7 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0460] In formula (sulfo-1), f8 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that f8 is 0 or 1. f9 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that f9 is 0 or 1. f10 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that f10 is 0 or 1.

[0461] In formula (sulfo-1), f11 is either 0 or 1. When f11 is 0, it is a benzene ring, and when f11 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, a benzene ring with f11 being 0 is preferred.

[0462] In formula (sulfo-1), f12 is 0, 1, 2, 3, or 4. The more iodine atoms in the cation structure there are, the higher the absorption, especially for EUV. However, this also leads to poor solvent solubility and concerns about precipitation in the resist composition. Therefore, f12 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0463] In formula (sulfo-1), f13 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that f13 is 0 or 1. f14 is 0, 1, or 2. From the viewpoint of synthesis, it is preferable that f14 is 0 or 1.

[0464] However, when f1 is 0, 0 ≤ f6 + f9 ≤ 4, and when f1 is 1, 0 ≤ f6 + f9 ≤ 6. When f2 is 0, 0 ≤ f7 + f10 ≤ 4, and when f2 is 1, 0 ≤ f7 + f10 ≤ 6. When f3 is 0, 1 ≤ f4 + f5 + f8 + f14 ≤ 4, and when f3 is 1, 1 ≤ f4 + f5 + f8 + f14 ≤ 6. When f11 is 0, 0 ≤ f12 + f13 ≤ 4, and when f11 is 1, 0 ≤ f12 + f13 ≤ 6. Also, f4 + f12 ≥ 1.

[0465] In formula (sulfo-1), R F1 ~R F3 Each of these is independently a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms. Among these, trifluoromethyl, trifluoromethoxy, and trifluorothiomethoxy groups are preferred. When f5 is 2, 3, or 4, each R F1 They may be the same or different from each other. When f6 is 2, 3, 4, 5 or 6, each R F2They may be the same or different from each other. When f7 is 2, 3, 4, 5 or 6, each R F3 They may be the same as or different from each other.

[0466] In formula (sulfo-1), R ct1 ~R ct4 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than iodine and fluorine atoms, a nitro group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, or a C1-C20 hydrocarbylthio group which may contain a heteroatom. The hydrocarbyl portion of the hydrocarbyl group, hydrocarbyloxy group, and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. For example, in the explanation of formula (1A), R 1 ~R 3 Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms in the hydrocarbyl portion of the hydrocarbyl group, hydrocarbyloxy group and hydrocarbylthio group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, and nitrogen atoms, and as a result, the group may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0467] Also, when f8 is 2, the two R ct1 The two Rs may be identical or different from each other. ct1 These may bond with each other to form a ring with the carbon atom to which they are bonded. When f9 is 2, two R ct2 The two Rs may be identical or different from each other. ct2These may bond with each other to form a ring with the carbon atoms to which they are bonded. When f10 is 2, the two R ct3 The two Rs may be identical or different from each other. ct3 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When f13 is 2, two R ct4 The two Rs may be identical or different from each other. ct4 These elements may bond with each other to form a ring with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornane rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, the ring may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0468] Furthermore, S in the sulfonium cation represented by formula (sulfo-1) + Aromatic rings that are directly bonded to each other are bonded to each other, forming S + They may form a ring together. Specific examples of the ring structure include those represented by the following formula. [ka] (In the equation, dashed lines represent connections.)

[0469] In the formula (sulfo-1), L C and L D These are, independently, a single bond, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonic acid amide bond, a carbonate bond, or a carbamate bond. Of these, L CThe bond is preferably a single bond, an ether bond, an ester bond, or a sulfonic acid ester bond, and more preferably an ester bond or a sulfonic acid ester bond. D The bond is preferably a single bond, an ether bond, or an ester bond, and more preferably a single bond.

[0470] In the formula (sulfo-1), X L This is a 1-40 carbon atom hydrocarbylene group which may contain single bonds or heteroatoms. The hydrocarbylene group may be linear, branched, or cyclic, and specific examples include an alkanediyl group, a cyclic saturated hydrocarbylene group, and an arylene group. Specific examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom.

[0471] X L Specific examples of C1-C40 hydrocarbylene groups that may contain heteroatoms represented by the formula are, but are not limited to, those shown below. In the formula below, * represents L C and L D This is a combination of the two. [ka]

[0472] [ka]

[0473] [ka]

[0474] [ka]

[0475] Of these, X L -0~X L -22, X L -29~XL -34, and X L -47~X L -58 is preferable.

[0476] The sulfonium cation represented by formula (sulfo-1) is preferably the one represented by the following formula (sulfo-1-1). [ka] (In the formula, f4~f10, f12~f14, R F1 ~R F3 , R ct1 ~R ct4 , L C , L D and X L (This is the same as above.)

[0477] The sulfonium cation represented by formula (sulfo-1-1) is preferably the one represented by the following formula (sulfo-1-2). [ka] (In the formula, f4~f10, R F1 ~R F3 and R ct1 ~R ct3 (This is the same as above.)

[0478] Specific examples of sulfonium cations represented by formula (sulfo-1) are listed below, but are not limited to these. In the following formula, Me represents a methyl group. [ka]

[0479] [ka]

[0480] [ka]

[0481]

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[0482]

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[0483]

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[0484]

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[0485]

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[0486]

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[0487]

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[0488]

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[0489]

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[0490]

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[0491]

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[0492]

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[0493]

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[0494]

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[0495]

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[0496]

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[0497]

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[0498]

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[0499]

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[0500]

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[0501]

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[0502] [ka]

[0503] [ka]

[0504] [ka]

[0505] [ka]

[0506] Specific examples of the iodonium cation mentioned above include, but are not limited to, those described in paragraph

[0181] of Japanese Patent Publication No. 2024-259.

[0507] A specific example of the ammonium cation is the one represented by the following formula (am-1). [ka] In formula (am-1), R ct5 ~R ct8 Each of these is independently a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. Also, R ct5 and R ct6 However, they may bond with each other to form a ring with the nitrogen atom to which they are bonded. A specific example of the hydrocarbyl group is R in the explanation of formula (1A). 1 ~R 3 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0508] Specific examples of ammonium cations represented by formula (am-1) are listed below, but are not limited to these. [ka]

[0509] The specific structures of the repeating units c1 to c5 include any combination of the anions and cations mentioned above.

[0510] Of the repeating units c1 to c5, repeating units c2 to c5 are preferred from the viewpoint of controlling acid diffusion, repeating units c2, c4, and c5 are more preferred from the viewpoint of the acid strength of the generated acid, and repeating unit c2 is even more preferred from the viewpoint of solvent solubility.

[0511] The polymer may contain repeating units (hereinafter also referred to as repeating unit d) having a structure in which a hydroxyl group is protected by an acid-unstable group. The repeating unit d is not particularly limited as long as it has one or more structures in which a hydroxyl group is protected and the protecting group decomposes upon the action of an acid to generate a hydroxyl group, but it is preferably represented by the following formula (d1). [ka]

[0512] In formula (d1), R A R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 41 R is a (g+1) valent hydrocarbon group having 1 to 30 carbon atoms, which may contain heteroatoms. 42 g is an acid-unstable group. g is 1, 2, 3, or 4.

[0513] In formula (d1), R 42 The acid-unstable group represented by can be any group that is deprotected by the action of an acid and generates a hydroxyl group. 42 The structure is not particularly limited, but acetal structures, ketal structures, hydrocarbyloxycarbonyl groups, and hydrocarbyloxymethyl groups represented by the following formula (d2) are preferred, and the hydrocarbyloxymethyl group represented by the following formula (d2) is particularly preferred. [ka] (In the formula, * represents a bond. R43 (This refers to a hydrocarbyl group with 1 to 15 carbon atoms.)

[0514] R 42 Specific examples of the acid-unstable group represented by formula (d2), the hydrocarbyloxymethyl group represented by formula (d2), and the repeating unit d are the same as those exemplified in the description of the repeating unit d described in Japanese Patent Application Publication No. 2020-111564.

[0515] The polymer may contain repeating units e derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or derivatives thereof. Specific examples of monomers that give repeating units e are listed below, but are not limited to these. [ka]

[0516] The polymer may contain repeating units f derived from indan, vinylpyridine, or vinylcarbazole.

[0517] In the polymer, the content ratios of repeating units a1, a2, a3, b1, b2, c1, c2, c3, c4, d, e, and f are preferably 0≦a1≦0.8, 0≦a2≦0.8, 0≦a3≦0.6, 0≦b1≦0.8, 0≦b2≦0.5, 0≦c1≦0.4, 0≦c2≦0.4, 0≦c3≦0.4, 0≦c4≦0.4, 0≦ d≦0.3, 0≦e≦0.3, and 0≦f≦0.3, more preferably 0≦a1≦0.7, 0≦a2≦0.7, 0≦a3≦0.5, 0≦b1≦0.7, 0≦b2≦0.4, 0≦c1≦0.3, 0≦c2≦0.3, 0≦c3≦0.3, 0≦c4≦0.3, 0≦d≦0.2, 0≦e≦0.2, and 0≦f≦0.2, where a1+a2+a3+b1+b2+c1+c2+c3+c4+d+e+f≦1.0.

[0518] The weight-average molecular weight (Mw) of the polymer is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no risk of a decrease in resolution due to the inability to ensure a difference in dissolution rate before and after exposure. In this invention, Mw is a polystyrene-converted value measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent.

[0519] The molecular weight distribution (Mw / Mn) of the polymer tends to have a greater influence as the pattern rule becomes finer. Therefore, in order to obtain a resist composition suitable for fine pattern dimensions, it is preferable that the Mw / Mn is narrowly dispersed between 1.0 and 2.0. Within this range, there are few low molecular weight or high molecular weight polymers, and there is no risk of foreign matter being observed on the pattern or deterioration of the pattern shape after exposure.

[0520] One example of a method for synthesizing the aforementioned polymer is to heat a monomer that provides the repeating units described above in an organic solvent with a radical polymerization initiator added, and polymerize it.

[0521] Specific examples of organic solvents used during polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyrolactone (GBL). Specific examples of polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of these initiators added is preferably 0.01 to 25 mol% of the total amount of monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, and more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the viewpoint of production efficiency.

[0522] The polymerization initiator may be added to the monomer solution and supplied to the reaction vessel, or an initiator solution may be prepared separately from the monomer solution and each supplied to the reaction vessel independently. Since the polymerization reaction may proceed and a superpolymer may be formed by radicals generated from the initiator during the waiting time, it is preferable from a quality control viewpoint to prepare the monomer solution and the initiator solution independently and add them dropwise. The acid-unstable group may be used as is, introduced into the monomer, or it may be protected or partially protected after polymerization. In addition, known chain transfer agents such as dodecyl mercaptan or 2-mercaptoethanol may be used in combination to adjust the molecular weight. In this case, the amount of these chain transfer agents added is preferably 0.01 to 20 mol% of the total amount of monomers to be polymerized.

[0523] In the case of monomers containing hydroxyl groups, the hydroxyl groups may be substituted with acetal groups that are easily deprotected by acids such as ethoxyethoxy groups during polymerization, and then deprotected with a weak acid and water after polymerization. Alternatively, they may be substituted with acetyl groups, formyl groups, pivaloyl groups, etc., and then alkaline hydrolysis may be performed after polymerization.

[0524] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene may be polymerized by heating in an organic solvent with a radical polymerization initiator. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene may be used, and after polymerization, the acetoxy group may be deprotected by alkaline hydrolysis to obtain polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0525] Specific examples of bases that can be used during alkaline hydrolysis include aqueous ammonia and triethylamine. The reaction temperature is preferably -20 to 100°C, more preferably 0 to 60°C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0526] The amount of each monomer in the monomer solution can be appropriately set, for example, to achieve a preferred content ratio of the repeating units described above.

[0527] The polymer obtained by the above manufacturing method may be treated as a final product if it is a reaction solution obtained by a polymerization reaction, or as a final product if it is a powder obtained by a purification process such as a reprecipitation method in which the polymerization solution is added to a poor solvent and a powder is obtained. However, from the viewpoint of work efficiency and quality stabilization, it is preferable to treat the polymer solution obtained by dissolving the powder obtained by the purification process in a solvent as the final product.

[0528] Specific examples of solvents used in this process include ketones such as cyclohexanone and methyl-2-n-pentyl ketone, as described in paragraphs

[0144] to

[0145] of Japanese Patent Publication No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether. Examples include ethers such as ethers; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as GBL; alcohols such as diacetone alcohol (DAA); high-boiling point alcoholic solvents such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol; and mixed solvents thereof.

[0529] In the polymer solution, the concentration of the polymer is preferably 0.01 to 30% by mass, and more preferably 0.1 to 20% by mass.

[0530] It is preferable to filter the reaction solution or polymer solution. Filtering removes foreign matter and gel that may cause defects, which is effective in stabilizing quality.

[0531] Examples of filter materials used in the aforementioned filter filtration include fluorocarbon, cellulose, nylon, polyester, and hydrocarbon materials. However, in the filtration process of the resist composition, filters made of fluorocarbon materials such as Teflon (registered trademark), hydrocarbon materials such as polyethylene and polypropylene, or nylon are preferred. The pore size of the filter can be appropriately selected according to the desired level of cleanliness, but is preferably 100 nm or less, and more preferably 20 nm or less. These filters may be used individually or in combination. The filtration method may involve passing the solution through only once, but it is more preferable to circulate the solution and filter it multiple times. The filtration process can be carried out in any order and number of times in the polymer manufacturing process, but it is preferable to filter the reaction solution after the polymerization reaction, the polymer solution, or both.

[0532] (B) The base polymer may be used alone, or two or more types with different composition ratios, Mw and / or Mw / Mn may be used in combination. In addition, (B) the base polymer may also contain hydrogenated ring-opening metathesis polymers, for which those described in Japanese Patent Publication No. 2003-66612 may be used.

[0533] [(C) Organic Solvents] The chemically amplified resist composition of the present invention may contain an organic solvent as component (C). The organic solvent (C) is not particularly limited as long as it is capable of dissolving the components described above and the components described later. Specific examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; keto alcohols such as DAA; ethers such as PGME, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as GBL; and mixed solvents of these.

[0534] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, ethyl lactate, DAA, and mixtures thereof are preferred, as they exhibit particularly excellent solubility of the base polymer of component (B).

[0535] In the chemically amplified resist composition of the present invention, the content of (C) organic solvent is preferably 200 to 5000 parts by mass, and more preferably 400 to 3500 parts by mass, per 80 parts by mass of (B) base polymer. (C) organic solvent may be used alone or as a mixture of two or more types.

[0536] [(D) Photoacid Generator] The chemically amplified resist composition of the present invention may contain a photoacid generator as component (D). The photoacid generator is not particularly limited as long as it is a compound that generates an acid with stronger acidity than the carboxylic acid that generates a quencher of component (A) upon irradiation with high-energy rays.

[0537] Suitable photoacid generators include those represented by the following formulas (2) or (3). [ka]

[0538] In formula (2), R 101 ~R 105 Each of these is independently a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom. 101 , R 102 and R 103 Any two of these may bond with each other to form a ring with the sulfur atom to which they are bonded. A specific example of the hydrocarbyl group is R in the explanation of formula (1A). 1 ~R 3 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0539] Specific examples of sulfonium salt cations represented by formula (2) include, but are not limited to, those exemplified as specific examples of sulfonium cations represented by formula (1A), those described in paragraphs

[0102] to

[0125] of Japanese Patent Publication No. 2024-3744, those described in paragraphs

[0044] to

[0049] of International Publication No. 2024 / 128017, those described in paragraphs

[0035] to

[0046] of Japanese Patent No. 7491173, and those exemplified as specific examples of sulfonium cations represented by formula (sulfo-1). Specific examples of iodonium salt cations represented by formula (3) include, but are not limited to, those described in paragraph

[0181] of Japanese Patent Publication No. 2024-259.

[0540] In equations (2) and (3), Xa - This is an anion of a strong acid. Specific examples of the aforementioned strong acid anions include those represented by any of the formulas (c1-1) to (c1-5).

[0541] Furthermore, as the photoacid generator for component (D), one represented by the following formula (4) is also preferred. [ka]

[0542] In formula (4), R 201 and R 202 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain heteroatoms. 203 This is a hydrocarbylene group having 1 to 30 carbon atoms, which may contain heteroatoms. Also, R 201 , R 202 and R 203 Any two of these may bond with each other to form a ring with the sulfur atom to which they are bonded.

[0543] R 201 and R 202 The C1-C30 hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C30 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, and tricyclo[5.2.1.0 2,6Examples include cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as decyl groups and adamantyl groups; aryl groups having 6 to 30 carbon atoms, such as phenyl groups, methylphenyl groups, ethylphenyl groups, n-propylphenyl groups, isopropylphenyl groups, n-butylphenyl groups, isobutylphenyl groups, sec-butylphenyl groups, tert-butylphenyl groups, naphthyl groups, methylnaphthyl groups, ethylnaphthyl groups, n-propylnaphthyl groups, isopropylnaphthyl groups, n-butylnaphthyl groups, isobutylnaphthyl groups, sec-butylnaphthyl groups, tert-butylnaphthyl groups, anthracenyl groups, and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, the material may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0544] R 203The hydrocarbylene group, represented by , having 1 to 30 carbon atoms, may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkane diyl groups with 1 to 30 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl 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, heptadecane-1,17-diyl group, etc.; cyclop Examples include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as tananediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group; and arylene groups such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, and tert-butylnaphthylene group. Furthermore, some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. The heteroatom is preferably an oxygen atom.

[0545] In formula (4), L 21This is a 1-20 carbon atom hydrocarbylene group which may contain single bonds, ether bonds, or heteroatoms. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 203 Examples of hydrocarbylene groups represented by the same formula as those exemplified above include the same groups as those shown.

[0546] In formula (4), X a , X b , X c and X d Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. However, X a , X b , X c and X d At least one of these is a fluorine atom or a trifluoromethyl group.

[0547] The photoacid generator represented by formula (4) is preferably the one represented by formula (4') below. [ka]

[0548] In formula (4'), L 21 This is the same as above. X e R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 Each of these is a hydrocarbyl group having 1 to 20 carbon atoms, which may each contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (c1-1-1). fa1 Examples of hydrocarbyl groups represented by the formula are similar to those exemplified. x2 and y2 are independently 0, 1, 2, 3, 4, or 5, and z2 is 0, 1, 2, 3, or 4.

[0549] Specific examples of the photoacid generator represented by formula (4) include those similar to those exemplified as the photoacid generator represented by formula (2) in Japanese Patent Publication No. 2017-26980.

[0550] Among the photoacid generators, those containing anions represented by formula (c1-1-1) or (c1-4) are particularly preferred because they exhibit low acid diffusion and excellent solubility in solvents. Furthermore, those represented by formula (4') are particularly preferred because they exhibit extremely low acid diffusion.

[0551] If the chemically amplified resist composition of the present invention contains (D) a photoacid generator, its content is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass, per 80 parts by mass of the (B) base polymer. When the amount of (D) photoacid generator added is within the above range, the resolution is good and there is no risk of foreign matter problems occurring after development or peeling of the resist film, so it is preferable. (D) The photoacid generator may be used alone or in combination of two or more types.

[0552] [(E) Other Quenchers] The chemically amplified resist composition of the present invention may contain a quencher other than component (A) (hereinafter also referred to as "other quenchers") as component (E).

[0553] (E) Other specific examples of quenchers include onium salts represented by the following formulas (5) or (6). [ka]

[0554] In formula (5), R q1 This is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group. In formula (6), R q2 This is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a hydrogen atom or a heteroatom.

[0555] R q1 Specifically, the C1-C40 hydrocarbyl groups represented by include C1-C40 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0 2,6 Examples include cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as decyl groups and adamantyl groups; and aryl groups having 6 to 40 carbon atoms, such as phenyl groups, naphthyl groups, and anthracenyl groups. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, the group may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0556] R q2 Specifically, the hydrocarbyl group represented by R q1 In addition to the substituents exemplified as specific examples, other examples include fluorinated saturated hydrocarbyl groups such as trifluoromethyl and trifluoroethyl groups, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl groups.

[0557] Specific examples of anions of onium salts represented by formula (5) are listed below, but are not limited to these. [ka]

[0558] [ka]

[0559] [ka]

[0560] [ka]

[0561] Specific examples of anions of onium salts represented by formula (6) are listed below, but are not limited to these. [ka]

[0562] [ka]

[0563] [ka]

[0564] In equations (5) and (6), MQ +This is an onium cation. Examples of the onium cation include sulfonium cations, iodonium cations, ammonium cations, etc. Specific examples of the sulfonium cation include, but are not limited to, those exemplified as a specific example of a sulfonium cation represented by formula (1A), those described in paragraphs

[0102] to

[0125] of Japanese Patent Publication No. 2024-3744, those described in paragraphs

[0044] to

[0049] of International Publication No. 2024 / 128017, those described in paragraphs

[0035] to

[0046] of Japanese Patent No. 7491173, and those exemplified as a specific example of a sulfonium cation represented by formula (sulfo-1). Specific examples of iodonium cations include, but are not limited to, those described in paragraph

[0181] of Japanese Patent Publication No. 2024-259. Specific examples of the ammonium cation include, but are not limited to, those exemplified as a specific example of an ammonium cation represented by formula (am-1).

[0565] Specific examples of onium salts represented by formulas (5) and (6) include any combination of the anions and cations mentioned above. These onium salts can be easily prepared by ion exchange reactions using known organic chemical methods. For ion exchange reactions, refer to, for example, Japanese Patent Publication No. 2007-145797.

[0566] The onium salts represented by formulas (5) and (6) act as quenchers in the chemically amplified resist composition of the present invention. This is because each counteranion of the onium salt is a conjugate base of a weak acid. Here, a weak acid refers to an acidity that is not capable of deprotecting the acid-unstable groups of the acid-unstable group-containing units used in the base polymer. The onium salts represented by formulas (5) and (6) function as quenchers when used in combination with an onium salt type photoacid generator having a conjugate base of a strong acid, such as a sulfonic acid, as a counteranion. That is, when an onium salt that generates a strong acid, such as a sulfonic acid, and an onium salt that generates a weak acid, such as a carboxylic acid, are mixed and used, when the strong acid generated from the photoacid generator by high-energy ray irradiation collides with the onium salt having an unreacted weak acid anion, the weak acid is released by salt exchange, and an onium salt having a strong acid anion is produced. In this process, the strong acid is exchanged for a weak acid with lower catalytic activity, so the acid is seemingly deactivated, and acid diffusion can be controlled.

[0567] Furthermore, (E) other quenchers may include an onium salt having a sulfonium cation and a phenoxide anion moiety in the same molecule as described in Japanese Patent Publication No. 6848776, an onium salt having a sulfonium cation and a carboxylate anion moiety in the same molecule as described in Japanese Patent Publication No. 6583136 and Japanese Patent Application Publication No. 2020-200311, and an onium salt having an iodonium cation and a carboxylate anion moiety in the same molecule as described in Japanese Patent Publication No. 6274755.

[0568] Here, if the photoacid generator that produces a strong acid is an onium salt, as mentioned above, the strong acid produced by high-energy ray irradiation can be exchanged for a weak acid. On the other hand, it is thought that the weak acid produced by high-energy ray irradiation is unlikely to collide with the unreacted onium salt that produces the strong acid and undergo salt exchange. This is due to the phenomenon that onium cations are more likely to form ion pairs with the anions of stronger acids.

[0569] If the chemically amplified resist composition of the present invention contains (E) an onium salt represented by formula (5) or (6) as another quencher, the content thereof is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, per 80 parts by mass of the base polymer (B). The onium salt type quencher content is preferred when it is within the above range because it provides good resolution and does not significantly reduce sensitivity. The onium salt represented by formula (5) or (6) may be used alone or in combination of two or more.

[0570] The chemically amplified resist composition of the present invention may also contain (E) a nitrogen-containing compound as another quencher. Specific examples of the nitrogen-containing compound include primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Publication No. 2008-111103, particularly amine compounds having a hydroxyl group, ether bond, ester bond, lactone ring, cyano group, or sulfonic acid ester bond. Compounds of primary or secondary amines protected with a carbamate group, as described in Japanese Patent Application Publication No. 3790649, can also be cited.

[0571] Furthermore, a sulfonium sulfonate salt having a nitrogen-containing substituent may be used as the nitrogen-containing compound. Such a compound functions as a quencher in the unexposed area and loses its quenching ability in the exposed area through neutralization with its own generated acid, functioning as a so-called photodecayable base. By using a photodecayable base, the contrast between the exposed and unexposed areas can be further enhanced. For example, Japanese Patent Publication No. 2009-109595 and Japanese Patent Publication No. 2012-46501 can be referenced as examples of photodecayable bases.

[0572] If the chemically amplified resist composition of the present invention contains (E) a nitrogen-containing compound as another quencher, the content thereof is preferably 0.001 to 12 parts by mass, and more preferably 0.01 to 8 parts by mass, per 80 parts by mass of the base polymer (B). The nitrogen-containing compound may be used alone or in combination of two or more.

[0573] [(F) Surfactants] The chemically amplified resist composition of the present invention may further contain a surfactant as component (F). Preferably, the surfactant (F) is a surfactant that is insoluble or sparingly soluble in water and soluble in an alkaline developer, or a surfactant that is insoluble or sparingly soluble in both water and an alkaline developer. Examples of such surfactants can be found in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2011-16746.

[0574] As surfactants that are insoluble or poorly soluble in water and alkaline developer, among the surfactants described in the above publication, FC-4430 (manufactured by 3M), Surflon® S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Orfin® E1004 (manufactured by Nisshin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and oxetane ring-opening polymers represented by the following formula (surf-1) are preferred. [ka]

[0575] Here, R, Rf, A, B, C, m, and n apply only to formula (surf-1), notwithstanding the preceding description. R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. Examples of such aliphatic groups include the divalent ethylene group, 1,4-butylene group, 1,2-propylene group, 2,2-dimethyl-1,3-propylene group, and 1,5-pentylene group, while examples of trivalent or tetravalent aliphatic groups are listed below. [ka] (In the formula, the dashed lines represent bonds, which are substructures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.)

[0576] Among these, the 1,4-butylene group and the 2,2-dimethyl-1,3-propylene group are preferred.

[0577] Rf is a trifluoromethyl group or a pentafluoroethyl group, preferably a trifluoromethyl group. m is an integer from 0 to 3, n is an integer from 1 to 4, and the sum of n and m is the valence of R, an integer from 2 to 4. A is 1. B is an integer from 2 to 25, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. Furthermore, the order of each constituent unit in formula (surf-1) is not specified, and they may be bonded in a block-like manner or randomly. For details on the production of partially fluorinated oxetane ring-opening polymer surfactants, please refer to U.S. Patent No. 5,650,483, etc.

[0578] Surfactants that are insoluble or sparingly soluble in water and soluble in alkaline developers have the function of reducing water penetration and leaching by orienting themselves on the surface of the resist film when a resist protective film is not used in ArF immersion lithography. Therefore, they are useful in suppressing the elution of water-soluble components from the resist film and reducing damage to the exposure equipment. Furthermore, they are useful because they become solubilized during alkaline aqueous solution development after exposure or post-exposure bake (PEB) and are less likely to become foreign substances that cause defects. Such surfactants are insoluble or sparingly soluble in water and soluble in alkaline developers, and are polymer-type surfactants, also called hydrophobic resins, with those that have particularly high water repellency and improve water lubricity being preferred.

[0579] Specific examples of such polymer-type surfactants include those containing at least one repeating unit selected from any of the following formulas (7A) to (7E). [ka]

[0580] In formulas (7A) to (7E), R B is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 R is -CH2-, -CH2CH2-, -O-, or two separated -H atoms. s1Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. s2 R is a single bond or a linear or branched hydrocarbylene group having 1 to 5 carbon atoms. s3 Each of these is independently a hydrogen atom, a C1-C15 hydrocarbyl group or a fluorinated hydrocarbyl group, or an acid-unstable group. s3 If the group is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be interposed between the carbon-carbon bonds. s4 R is a (u+1) valent hydrocarbon group or fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is 1, 2, or 3. s5 These are, independently, hydrogen atoms, or -C(=O)-OR sa It is a group represented by R. sa This is a fluorinated hydrocarbyl group having 1 to 20 carbon atoms. s6 This is a hydrocarbyl group having 1 to 15 carbon atoms or a fluorinated hydrocarbyl group, and an ether bond or a carbonyl group may be interposed between the carbon-carbon bonds.

[0581] R s1 The C1-C10 hydrocarbyl group represented by is preferably a saturated hydrocarbyl group and may be linear, branched, or cyclic. Specific examples include C1-C10 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups; and C3-C10 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl groups. Of these, those with C1-C6 are preferred.

[0582] R s2 The hydrocarbylene group represented by is preferably a saturated hydrocarbylene group and may be linear, branched, or cyclic. Specific examples include methylene, ethylene, propylene, butylene, and pentylene groups.

[0583] R s3 or R s6 The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include saturated hydrocarbyl groups, alkenyl groups, alkynyl groups, and other aliphatic unsaturated hydrocarbyl groups, but saturated hydrocarbyl groups are preferred. A specific example of the saturated hydrocarbyl group is R s1 In addition to the examples given as hydrocarbyl groups represented by , other examples include undecyl groups, dodecyl groups, tridecyl groups, tetradecyl groups, pentadecyl groups, etc. s3 or R s6 Examples of fluorinated hydrocarbyl groups represented by the above-mentioned hydrocarbyl group include groups in which some or all of the hydrogen atoms bonded to the carbon atoms are replaced with fluorine atoms. As mentioned above, ether bonds or carbonyl groups may be interposed between these carbon-carbon bonds.

[0584] R s3 Specific examples of acid-unstable groups represented by the formulas (AL-3) to (AL-5) mentioned above include trialkylsilyl groups in which each alkyl group has 1 to 6 carbon atoms, and alkyl groups containing oxo groups with 4 to 20 carbon atoms.

[0585] R s4 The (u+1) valent hydrocarbon group or fluorinated hydrocarbon group represented by can be linear, branched, or cyclic. Specific examples include groups obtained by further removing u hydrogen atoms from the aforementioned hydrocarbyl group or fluorinated hydrocarbyl group.

[0586] R saThe fluorinated hydrocarbyl group represented by is preferably saturated and may be linear, branched, or cyclic. Specific examples include those in which some or all of the hydrogen atoms of the hydrocarbyl group are substituted with fluorine atoms, and specific examples of such include trifluoromethyl group, 2,2,2-trifluoroethyl group, 3,3,3-trifluoro-1-propyl group, 3,3,3-trifluoro-2-propyl group, 2,2,3,3-tetrafluoropropyl group, 1,1,1,3,3,3-hexafluoroisopropyl group, 2,2,3,3,4,4,4-heptafluorobutyl group, 2,2,3,3,4,4,5,5-octafluoropentyl group, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl group, 2-(perfluorobutyl)ethyl group, 2-(perfluorohexyl)ethyl group, 2-(perfluorooctyl)ethyl group, 2-(perfluorodecyl)ethyl group, etc.

[0587] Specific examples of repeating units represented by any of the formulas (7A) to (7E) are shown below, but are not limited to these. Note that in the formulas below, R B This is the same as described above. [ka]

[0588] [ka]

[0589] [ka]

[0590] [ka]

[0591] [ka]

[0592] [ka]

[0593] The polymer-type surfactant may further contain other repeating units other than those represented by formulas (7A) to (7E). Specific examples of other repeating units include those obtained from methacrylic acid and α-trifluoromethylacrylic acid derivatives. In the polymer-type surfactant, the content of the repeating units represented by formulas (7A) to (7E) is preferably 20 mol% or more, more preferably 60 mol% or more, and even more preferably 100 mol% of the total repeating units.

[0594] The Mw of the polymer-type surfactant is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. The Mw / Mn ratio is preferably 1.0 to 2.0, and more preferably 1.0 to 1.6.

[0595] A method for synthesizing the polymer-type surfactant involves polymerizing a monomer containing unsaturated bonds that give repeating units represented by formulas (7A) to (7E), and optionally other repeating units, by heating it in an organic solvent with a radical initiator. Specific examples of organic solvents used during polymerization include toluene, benzene, THF, diethyl ether, and dioxane. Specific examples of polymerization initiators include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. The acid-unstable group may be used as is after being introduced into the monomer, or it may be protected or partially protected after polymerization.

[0596] When synthesizing the polymer-type surfactant, known chain transfer agents such as dodecyl mercaptan or 2-mercaptoethanol may be used to adjust the molecular weight. In that case, the amount of these chain transfer agents added is preferably 0.01 to 10 mol% relative to the total number of moles of monomers to be polymerized.

[0597] When the chemically amplified resist composition of the present invention contains a surfactant (F), its content is preferably 0.1 to 50 parts by mass, and more preferably 0.5 to 10 parts by mass, per 80 parts by mass of the base polymer (B). If the content of the surfactant (F) is 0.1 parts by mass or more, the receding contact angle between the resist film surface and water is sufficiently improved, and if it is 50 parts by mass or less, the dissolution rate of the resist film surface in the developer is small, and the height of the formed fine pattern is sufficiently maintained. The surfactant (F) may be used alone or in combination of two or more types.

[0598] [(G) Other ingredients] The chemically amplified resist composition of the present invention may also contain (G) other components such as a compound that decomposes with acid to generate acid (acid-proliferating compound), an organic acid derivative, a fluorine-substituted alcohol, and a compound with an Mw of 3000 or less whose solubility in the developer changes due to the action of acid (dissolution inhibitor). As the acid-proliferating compound, compounds described in Japanese Patent Publication No. 2009-269953 or Japanese Patent Publication No. 2010-215608 can be referenced. When the acid-proliferating compound is included, its content is preferably 0 to 5 parts by mass, and more preferably 0 to 3 parts by mass, per 80 parts by mass of the (B) base polymer. If the content is too high, it becomes difficult to control acid diffusion, which may lead to deterioration of resolution and pattern shape. As the organic acid derivative, fluorine-substituted alcohol and dissolution inhibitor, compounds described in Japanese Patent Publication No. 2009-269953 or Japanese Patent Publication No. 2010-215608 can be referenced.

[0599] [Pattern formation method] The pattern formation method of the present invention includes the steps of forming a resist film on a substrate using the chemically amplified resist composition described above, exposing the resist film with high-energy rays, and developing the exposed resist film using a developer.

[0600] As the substrate, for example, substrates for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coatings, etc.) or substrates for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) can be used.

[0601] The resist film can be formed by, for example, applying the chemically amplified resist composition onto a substrate using a method such as spin coating to a film thickness of preferably 0.05 to 2 μm, and then pre-baking it on a hot plate at preferably 60 to 150°C for 1 to 10 minutes, more preferably 80 to 140°C for 1 to 5 minutes.

[0602] High-energy beams used for exposure of resist films include KrF excimer laser light, ArF excimer laser light, EB, and EUV with wavelengths of 3 to 15 nm. When using KrF excimer laser light, ArF excimer laser light, or EUV, exposure is performed using a mask to form the desired pattern, with an exposure dose of preferably 1 to 200 mJ / cm². 2 More preferably 10-100 mJ / cm² 2 This can be done by irradiating in such a manner. When using EB, the exposure amount is preferably 1 to 300 μC / cm², either using a mask to form the desired pattern or directly. 2 More preferably 10-200 μC / cm 2 Irradiate in such a way that it results in the following.

[0603] In addition to conventional exposure methods, immersion methods can also be used, in which a liquid with a refractive index of 1.0 or higher is interposed between the resist film and the projection lens. In this case, a protective film insoluble in water can also be used.

[0604] The aforementioned water-insoluble protective film is used to prevent leaching from the resist film and to improve the water-repellent properties of the film surface, and there are two main types. One is an organic solvent-removable type that requires removal before alkaline aqueous solution development using an organic solvent that does not dissolve the resist film, and the other is an alkaline aqueous solution-soluble type that is soluble in alkaline developer and removes the protective film along with the soluble parts of the resist film. The latter is particularly preferably based on a polymer having a 1,1,1,3,3,3-hexafluoro-2-propanol residue that is insoluble in water and soluble in alkaline developer, and dissolved in an alcohol-based solvent having 4 or more carbon atoms, an ether-based solvent having 8 to 12 carbon atoms, or a mixture thereof. Alternatively, the aforementioned water-insoluble and alkaline developer-soluble surfactant can be dissolved in an alcohol-based solvent having 4 or more carbon atoms, an ether-based solvent having 8 to 12 carbon atoms, or a mixture thereof.

[0605] PEB may be performed after exposure. PEB can be performed, for example, by heating on a hot plate, preferably at 60-150°C for 1-5 minutes, more preferably at 80-140°C for 1-3 minutes.

[0606] Development is carried out using a developer solution, preferably an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) in an amount of 0.1 to 5% by mass, more preferably 2 to 3% by mass, and by conventional methods such as the dip method, puddle method, or spray method for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, which dissolves the exposed areas and forms the desired pattern on the substrate.

[0607] Furthermore, after the resist film is formed, a rinse with pure water may be performed to extract acid generators or other substances from the film surface, or to wash away particles. Alternatively, a rinse may be performed after exposure to remove any water remaining on the film.

[0608] Furthermore, patterns may be formed by a double patterning method. Examples of double patterning methods include the trench method, in which a 1:3 trench pattern base is processed with the first exposure and etching, and then a 1:3 trench pattern is formed by a second exposure with a shifted position to form a 1:1 pattern; and the line method, in which a first base for a 1:3 isolated pattern is processed with the first exposure and etching, and then a second exposure with a shifted position to process a second base formed beneath the first base for a 1:3 isolated pattern to form a 1:1 pattern with half the pitch.

[0609] In the pattern formation method of the present invention, a negative tone development method may be used in which an organic solvent is used as the developer to dissolve the unexposed areas instead of the alkaline aqueous solution.

[0610] For the aforementioned organic solvent development, the developer may be 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotate, ethyl crotate, propyl acetate, methyl propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotate, ethyl crotate, propyl propyl acetate, methyl propyl formate, methyl pentenoate, methyl crotate, ethyl crotate, propyl propyl acetate, methyl propyl formate, methyl pentenoate, methyl crotate, ethyl crotate, propyl propyl acetate, methyl propyl formate, methyl pentenoate, methyl crotate, methyl propyl acetate, methyl propyl formate, methyl propyl formate, methyl pentenoate, methyl crotate, methyl propyl acetate, methyl propyl formate, methyl propyl acetate, methyl pentenoate, methyl crotate, methyl propyl acetate, methyl propyl acetate, methyl pentenoate, methyl crotate, methyl propyl acetate, methyl propyl acetate, methyl pentenoate, methyl methyl crotate, methyl propyl acetate, methyl propyl acetate, methyl pentenoate, methyl methyl crotate, methyl propyl acetate, methyl propyl acetate, methyl propyl acetate, methyl pentenoate, methyl Methyl ropionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl phenyl acetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, 2-phenylethyl acetate, etc. can be used. These organic solvents may be used individually or in mixtures of two or more. [Examples]

[0611] The present invention will be specifically described below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. The apparatus used is as follows. • MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0612] [1] Synthesis of sulfonium salts [Example 1-1] Synthesis of sulfonium salt PDQ-1 [ka]

[0613] (1) Synthesis of sulfonium salt PDQ-1 Under a nitrogen atmosphere, the starting material SM-1 (4.0 g), sodium bicarbonate (1.0 g), and water (20 g) were mixed in a reaction vessel and stirred at an internal temperature of 45°C for 1 hour. After that, the reaction mixture was cooled to room temperature, and the starting material SM-2 (15.0 g, equivalent to 0.012 mol) and methyl isobutyl ketone (30 g) were added and stirred at room temperature for 30 minutes. After stirring, the organic layer was separated, washed with water, and then concentrated under reduced pressure. The concentrate was purified by silica gel chromatography to obtain 5.9 g of the target product, sulfonium salt PDQ-1, as an oily substance (yield 86%).

[0614] The TOF-MS results for PDQ-1 are shown below. MALDI TOF-MS: POSITIVE M + 447(C 20 H 16 F5O2S2 + equivalent) NEGATIVE M - 403(C8H5I2O3 - equivalent)

[0615] [Examples 1-2 to 1-7] Synthesis of sulfonium salts PDQ-2 to PDQ-7 Using corresponding raw materials and known organic chemical reactions, sulfonium salts PDQ-2 to PDQ-7, represented by the following formulas, were synthesized. [ka]

[0616] [Synthesis Example] Synthesis of base polymers (polymers P-1 to P-5) Each monomer was combined and copolymerized in MEK, a solvent. The mixture was then placed in hexane, and the precipitated solid was washed with hexane, isolated, and dried to obtain base polymers (polymers P-1 to P-5) with the following compositions. The compositions of the obtained base polymers are: 1 Mw and Mw / Mn were confirmed by H-NMR using GPC (solvent: DMF, standard: polystyrene). [ka]

[0617] [3] Preparation of chemically amplified resist compositions [Examples 2-1 to 2-30, Comparative Examples 1-1 to 1-20] The quenchers of the present invention (PDQ-1 to PDQ-7), comparative quenchers (PDQ-A to PDQ-D), photoacid generators (PAG-X, PAG-Y), base polymers (P-1 to P-5), and other quenchers (AQ-1, AQ-2) were dissolved in a solvent containing 0.01% by mass of surfactant A (Omnova) in the compositions shown in Tables 1 and 2 below to prepare solutions. These solutions were then filtered through a 0.2 μm Teflon® type filter to prepare chemically amplified resist compositions (R-1 to R-30 and CR-1 to CR-20).

[0618] [Table 1]

[0619] [Table 2]

[0620] In Tables 1 and 2, the solvent, photoacid generators PAG-X and PAG-Y, comparative quenchers PDQ-A to PDQ-D, other quenchers AQ-1 and AQ-2, and surfactant A are as follows. • Solvent: PGMEA (Propylene glycol monomethyl ether acetate) EL (Ethyl Lactate) DAA (Diacetone Alcohol)

[0621] • Photoacid generators: PAG-X, PAG-Y [ka]

[0622] • Comparative quenchers: PDQ-A to PDQ-D [ka]

[0623] Other Quenchers: AQ-1, AQ-2 [ka]

[0624] • Surfactant A: 3-methyl-3-(2,2,2-trifluoroethoxymethyl)oxetane-tetrahydrofuran-2,2-dimethyl-1,3-propanediol copolymer (manufactured by Omnova) [ka] a:(b+b'):(c+c')=1:4~7:0.01~1 (molar ratio) Mw=1500

[0625] [4] EUV lithography evaluation (1) [Examples 3-1 to 3-30, Comparative Examples 2-1 to 2-20] Each chemically amplified resist composition (R-1 to R-30, CR-1 to CR-20) was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. had been formed to a thickness of 20 nm. A resist film with a thickness of 50 nm was then fabricated by pre-baking at 100°C for 60 seconds using a hot plate. The resist film was then exposed to an LS pattern with a wafer dimension of 18 nm and a pitch of 36 nm using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, dipole illumination), with exposure dose and focus varied (exposure dose pitch: 1 mJ / cm²). 2 The process was carried out while adjusting the focus pitch (0.020 μm), and after exposure, PEB was performed for 60 seconds at the temperatures shown in Tables 4 and 5. Then, paddle development was performed for 30 seconds with a 2.38 mass% TMAH aqueous solution, rinsed with a surfactant-containing rinse material, and spin-dried to obtain a positive type pattern. The obtained LS patterns were observed using a Hitachi High-Technologies Corporation measuring SEM (CG6300), and sensitivity, EL, LWR, depth of field (DOF), and tilt limit were evaluated according to the method described below. Development defects were also evaluated for the obtained LS patterns. The results are shown in Tables 3 and 4.

[0626] [Sensitivity evaluation] Optimal exposure amount E for obtaining an LS pattern with a line width of 18 nm and a pitch of 36 nm op (mJ / cm 2 The value of ) was calculated and defined as the sensitivity. The smaller this value, the higher the sensitivity.

[0627] [EL rating] The exposure amount formed within ±10% (16.2 to 19.8 nm) of the 18 nm space width in the aforementioned LS pattern was used to calculate the EL (unit: %) using the following formula. A larger value indicates better performance. EL(%)=(|E1-E2| / E op ) × 100 E1: Optimal exposure amount to give an LS pattern with a line width of 16.2 nm and a pitch of 36 nm. E2: Optimal exposure amount to give an LS pattern with a line width of 19.8 nm and a pitch of 36 nm. E op : Optimal exposure amount to give an LS pattern with a line width of 18nm and a pitch of 36nm

[0628] [LWR rating] E op The LS pattern obtained by irradiation was measured at 10 points along the longitudinal direction of the line, and the LWR was calculated as three times the standard deviation (σ) (3σ) from the results. The smaller this value, the less roughness and the more uniform the line width pattern obtained.

[0629] [DOF rating] To evaluate the depth of focus, the focus range formed within ±10% of the 18nm dimension (16.2 to 19.8nm) in the aforementioned LS pattern was determined. A larger value indicates a wider depth of focus.

[0630] [Evaluation of the limit of line pattern collapse] The line dimensions for each exposure amount at the optimal focus of the aforementioned LS pattern were measured at 10 points along the longitudinal direction. The thinnest line dimension obtained without collapse was defined as the collapse limit dimension. The smaller this value, the better the collapse limit.

[0631] [Development defect evaluation] The LS pattern with a line width of 18 nm and a pitch of 36 nm, formed with the aforementioned optimal exposure, is then inspected using a KLA2360 (product name) defect inspection device manufactured by KLA-Tencor. The pixel size of the defect inspection device is set to 0.16 μm and the threshold to 20. Defects (number of defects / cm²) are extracted from the differences resulting from the superposition of the comparison image and the pattern at the pixel level. 2 ) detects the number of defects per unit area (pieces / cm²). 2 The number of development defects per unit area (units / cm²) was calculated. Subsequently, a defect review was conducted to classify and extract development defects from all defects, and the number of development defects per unit area (units / cm²) was calculated. 2 The performance index (%) was calculated. Values ​​less than 0.5 were classified as A, values ​​between 0.5 and 1.0 as B, values ​​between 1.0 and 5.0 as C, and values ​​of 5.0 or higher as D. A smaller value indicates better performance.

[0632] [Table 3]

[0633] [Table 4]

[0634] The results shown in Tables 3 and 4 indicate that the chemically amplified resist composition containing the photoacid generator of the present invention exhibits excellent EL, LWR, and DOF with good sensitivity. Furthermore, it was confirmed that the tilt limit value is small and that the pattern is resistant to tilting even in the formation of fine patterns. Moreover, it was confirmed that development defects are suppressed. Therefore, the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[0635] [5] EUV Lithography Evaluation (2) [Examples 4-1 to 4-30, Comparative Examples 3-1 to 3-20] Each chemically amplified resist composition (R-1 to R-30, CR-1 to CR-20) was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. had been formed to a thickness of 20 nm. The resist film was then pre-baked at 105°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. The resist film was exposed using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, wafer-mounted dimensions of 46 nm pitch, +20% bias hole pattern mask). PEB was performed using a hot plate at the temperatures listed in Tables 5 and 6 for 60 seconds, and development was performed with a 2.38% by mass TMAH aqueous solution for 30 seconds to form a hole pattern with dimensions of 23 nm. Using a Hitachi High-Technologies Corporation length-measuring SEM (CG6300), the exposure amount when a hole dimension of 23 nm was formed was measured and defined as the sensitivity. The dimensions of 50 holes at this point were also measured, and the CDU was defined as three times the standard deviation (σ) calculated from these results (3σ). The results are shown in Tables 5 and 6.

[0636] [Table 5]

[0637] [Table 6]

[0638] The results shown in Tables 5 and 6 confirm that the chemically amplified resist composition of the present invention exhibits good sensitivity and excellent CDU (Chemical Dust Unit) properties.

Claims

1. A sulfonium salt comprising a sulfonium cation represented by the following formula (1A) and an aromatic carboxylic acid anion represented by the following formula (1B). 【Chemistry 1】 (In the formula, n1 is 0 or 1. n2 is 0, 1 or 2. n3 is 0, 1 or 2. n4 is 0, 1 or 2. However, when n1 is 0, 0 ≤ n2 + n3 + n4 ≤ 5, and when n1 is 1, 0 ≤ n2 + n3 + n4 ≤ 7. n5 is 0 or 1. n6 is 0, 1 or 2. n7 is 0, 1 or 2. n8 is 0, 1 or 2. However, when n5 is 0, 0 ≤ n6 + n7 + n8 ≤ 5, and when n5 is 1, then 0 ≤ n6 + n7 + n8 ≤ 7. n9 is 0 or 1. n10 is 0, 1 or 2. n11 is 0, 1 or 2. n12 is 0, 1 or 2. However, when n9 is 0, then 0 ≤ n10 + n11 + n12 ≤ 5, and when n9 is 1, then 0 ≤ n10 + n11 + n12 ≤ 7. Also, 1 ≤ n2 + n6 + n10 ≤ 6, and 1 ≤ n3 + n7 + n11 ≤ 6. R 1 , R 2 and R 3 Each of these is an independent hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. When n3 is 2, each R 1 These may be the same or different from each other. When n7 is 2, each R 2 These may be the same or different from each other. When n11 is 2, each R 3 They may be the same as or different from each other. R 4 , R 5 and R 6 are each independently a halogen atom, a nitro group, a hydroxy group, a carboxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a hetero atom or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a hetero atom. When n4 is 2, each R 4 may be the same as or different from each other, and two R 4 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. When n8 is 2, each R 5 may be the same as or different from each other, and two R 5 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. When n12 is 2, each R 6 may be the same as or different from each other, and two R 6 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. Also, S + Two of the three aromatic rings bonded to it may bond to each other, forming a ring with the sulfur atom to which they are bonded. 【Chemistry 2】 (In the equation, n11 is 0 or 1. n12 is 1, 2, 3 or 4. n13 is 0, 1 or 2. n14 is 0, 1, 2, 3 or 4. However, when n11 is 0, 2 ≤ n12 + n13 + n14 ≤ 5, and when n11 is 1, 2 ≤ n12 + n13 + n14 ≤ 7.) L A These are single bonds, oxygen atoms, sulfur atoms, ester bonds, or carbonate bonds. R 7 is, L A When it is a single bond, it is a hydroxyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom, L A When it is an oxygen atom, a sulfur atom, an ester bond, or a carbonate bond, it is a C1-C20 hydrocarbyl group (excluding acid-unstable groups) or an acid-unstable group, which may also contain a hydrogen atom or a heteroatom. R 8 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than iodine, a nitro group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, or a C1-C20 hydrocarbylthio group which may contain a heteroatom. When n14 is 2, 3, or 4, multiple R 8 These atoms may bond to each other, forming a ring structure together with the carbon atoms on the aromatic ring to which they are bonded, and the -CH of the ring 2 (Some of the hyphens may be replaced with -O- or -S-.)

2. The sulfonium salt according to claim 1, wherein the sulfonium cation is represented by the following formula (1A-1). 【Transformation 3】 (In the formula, n2 to n4, n6 to n8, n10 to n12 and R 1 ~R 6 (This is the same as above.)

3. The sulfonium salt according to claim 1, wherein the aromatic carboxylic acid anion is represented by the following formula (1B-1). 【Chemistry 4】 (In the formula, n12 to n14, L A , R 7 and R 8 (This is the same as above.)

4. L A The sulfonium salt according to claim 1, wherein the atom is an oxygen atom or an ester bond.

5. L A is an oxygen atom, a sulfur atom, an ester bond, or a carbonate bond, R 3 The sulfonium salt according to claim 1, wherein is an acid-unstable group.

6. The sulfonium salt according to claim 1, wherein the acid-unstable group is represented by the following formula (AL-1) or (AL-2). 【Transformation 5】 (In the formula, p1 and p2 are independently 0 or 1. Q1 and q2 are independently 0, 1, 2, 3, or 4.) R L1 , R L2 and R L3 Each of these is independently a hydrocarbyl group having 1 to 12 carbon atoms, and the -CH of the hydrocarbyl group 2 A portion of the - may be substituted with -O- or -S-, and if the hydrocarbyl group includes an aromatic ring, some or all of the hydrogen atoms of the aromatic ring may be substituted with a halogen atom, a cyano group, a nitro group, a C1-C4 alkyl group which may contain a halogen atom, or a C1-C4 alkoxy group which may contain a halogen atom. Also, R L1 and R L2 However, they may bond to each other and form a ring with the carbon atoms to which they are bonded, and the -CH of the ring 2 Some of the hyphens may be replaced with -O- or -S-. R L4 and R L5 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. L6 This is a hydrocarbyl group having 1 to 20 carbon atoms, and the -CH of the hydrocarbyl group 2 A portion of the - may be replaced with -O- or -S-. Also, R L5 and R L6 However, they bond to each other, and the carbon atoms and L that they bond to are bonded together. B Together, a heterocyclic group having 3 to 20 carbon atoms may be formed, and the -CH of the heterocyclic group 2 Some of the hyphens may be replaced with -O- or -S-. L B It is either -O- or -S-. R La ~R Ld Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom. * indicates a bond with an adjacent oxygen or sulfur atom.

7. A quencher comprising a sulfonium salt according to any one of claims 1 to 6.

8. A chemically amplified resist composition comprising the quencher described in claim 7.

9. A chemically amplified resist composition according to claim 8, comprising a base polymer containing a polymer having repeating units represented by the following formula (a1). 【Transformation 6】 (In the formula, R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 This consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-O-X 11 - or * - C (= O) - NH - X 11 - and the phenylene group or naphthylene group may be substituted with a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. 11 This is a saturated hydrocarbylene group, phenylene group, or naphthylene group having 1 to 10 carbon atoms, and the saturated hydrocarbylene group may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. * represents a bond with a carbon atom of the main chain. AL 1 It is an acid-unstable group.

10. The chemically amplified resist composition according to claim 9, wherein the base polymer comprises repeating units represented by the following formula (a2). 【Transformation 7】 (In the formula, R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 2 The bond is either a single bond or *-C(=O)-O-. The asterisk (*) represents a bond with a carbon atom in the main chain. R 11 This is a C1-C20 hydrocarbyl group which may contain a halogen atom, a cyano group, a hydroxyl group, a nitro group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyl group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. When a1 is 2, 3, or 4, each R 11 They may be the same as or different from each other. AL 2 It is an acid-unstable group. (a is 0, 1, 2, 3, or 4.)

11. The chemically amplified resist composition according to claim 9, wherein the base polymer comprises repeating units represented by the following formula (a3). 【Transformation 8】 (In the formula, b1 is 0 or 1. When b1 is 0, b2 is 0, 1, 2 or 3, and when b1 is 1, b2 is 0, 1, 2, 3, 4 or 5.) R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 3 The bonds are single bonds, *-C(=O)-O-, or *-C(=O)-NH-. The asterisk (*) represents a bond with a carbon atom in the main chain. X 4 This refers to a single bond, an aliphatic hydrocarbylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining these. X 5 and X 6 Each of these is independently either an oxygen atom or a sulfur atom. However, X 4 and X 6 It is bonded to the carbon atom adjacent to the aromatic ring. R 12 and R 13 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom. Also, R 12 and R 13 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. R 14 This may include a halogen atom, a hydroxyl group, a cyano group, a nitro group, a C1-C20 hydrocarbyl group which may contain a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom, a C1-C20 hydrocarbylthio group which may contain a heteroatom, or -N(R) 14A )(R 14B ) is R 14A and R 14B Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. When b2 is 2 or more, each R 14 They may be the same or different from each other, and there may be multiple R 14 These atoms may bond with each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded.

12. The chemically amplified resist composition according to claim 9, wherein the base polymer comprises repeating units represented by the following formula (b1) or (b2). 【Chemistry 9】 (In the formula, R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y 1 The bond is either a single bond or *-C(=O)-O-. The asterisk (*) represents a bond with a carbon atom in the main chain. R 21 This is a group having 1 to 20 carbon atoms that includes a hydrogen atom or at least one structure selected from a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic acid anhydride (-C(=O)-O-C(=O)-). R 22 This is a C1-C20 hydrocarbyl group which may contain a halogen atom, a carboxyl group, a nitro group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyl group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. When c2 is 2, 3, or 4, each R 22 They may be the same as or different from each other. c1 is 1, 2, 3, or 4. c2 is 0, 1, 2, 3, or 4, where 1 ≤ c1 + c2 ≤ 5.

13. The chemically amplified resist composition according to claim 9, wherein the base polymer comprises at least one selected from repeating units represented by the following formula (c1), repeating units represented by the following formula (c2), repeating units represented by the following formula (c3), repeating units represented by the following formula (c4), and repeating units represented by the following formula (c5). 【Chemistry 10】 (In the formula, d1 and d2 are independently 0, 1, 2, or 3. e1 is 0 or 1. e2 is 0, 1, 2, 3, or 4. e3 is 0, 1, 2, 3, or 4. However, when e1 is 0, 0 ≤ e2 + e3 ≤ 4, and when e1 is 1, 0 ≤ e2 + e3 ≤ 6.) R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z 1 This is a phenylene group which may have a single bond or a substituent. Z 2 is a single bond, **-C(=O)-O-Z 21 -, **-C(=O)-NH-Z 21 - or **-O-Z 21 -. Z 21 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group or a divalent group obtained by combining these, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond or a hydroxy group. Z 3 These are single bonds, ether bonds, ester bonds, amide bonds, sulfonic acid ester bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Z 4 This is a single bond, or a divalent group obtained by combining an aliphatic hydrocarbylene group, a phenylene group, or a combination thereof, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z 5 Each of these independently comprises a single bond, a phenylene group which may have substituents, a naphthylene group which may have substituents, or *-C(=O)-O-Z 51 - is Z 51 This is an aliphatic hydrocarbylene group, a phenylene group, or a naphthylene group having 1 to 10 carbon atoms, and the aliphatic hydrocarbylene group may contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or a lactone ring. Z 6 These are single bonds, ether bonds, ester bonds, amide bonds, sulfonic acid ester bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Z 7 is, independently of each other, a single bond, ***-Z 71 -C(=O)-O-, ***-C(=O)-NH-Z 71 - or ***-O-Z 71 -. Z 71 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. Z 8 These are, independently, single bonds, ****-Z 81 -C(=O)-O-, ****-C(=O)-NH-Z 81 - or ****-O-Z 81 - is Z 81 This is a hydrocarbylene group having 1 to 20 carbon atoms, which may contain heteroatoms. Z 9 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, trifluoromethyl groups, and *-C(=O)-O-Z. 91 -, *-C(=O)-N(H)-Z 91 - or * - O - Z 91 - is Z 91 This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. * represents a bond with a carbon atom in the main chain. ** represents Z 1 This represents a combination with Z. *** represents Z 6 This represents a combination with Z. **** is Z 7 This represents a combination of two things. L 1 These are single bonds, ether bonds, ester bonds, carbonyl groups, sulfonic acid ester bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Rf 1 and Rf 2 Each of these is independently either a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 3 and Rf 4 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 5 and Rf 6 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. However, all Rf 5 and Rf 6 They cannot simultaneously become hydrogen atoms. Rf 7 This is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated alkylthio group having 1 to 6 carbon atoms. R 31 and R 32 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. Also, R 31 and R 32 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. R 33 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than fluorine atoms, or heteroatoms. When e3 is 2, 3, or 4, each R 33 They may be the same or different from each other, and there may be multiple R 33 These atoms may bond with each other to form a ring with the carbon atoms to which they are bonded. M - It is a non-nucleophilic counterion. A + (This is an onium cation.)

14. Furthermore, the chemically amplified resist composition according to claim 8, further comprising an organic solvent.

15. Furthermore, the chemically amplified resist composition according to claim 8, further comprising a photoacid generator that generates a strong acid.

16. Furthermore, the chemical amplification resist composition according to claim 8, comprising a quencher other than the quencher described in claim 7.

17. Furthermore, the chemically amplified resist composition according to claim 8, further comprising a surfactant.

18. A pattern forming method comprising the steps of: forming a resist film on a substrate using the chemically amplified resist composition described in claim 8; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer.

19. The pattern formation method according to claim 18, wherein the high-energy beam is KrF excimer laser light, ArF excimer laser light, an electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

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