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 represented by the following formula (1). TIFF2026126678000682.tif54140

Description

[Technical Field]

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

[0002] In recent years, with the increasing integration and speed of LSIs, there has been a demand for miniaturization of pattern rules, and far ultraviolet lithography and extreme ultraviolet (EUV) lithography are considered promising next-generation microfabrication technologies.

[0003] Photolithography using ArF excimer laser light (ArF lithography) began to be used partially for the fabrication of 130nm node devices and became the main lithography technology for 90nm node devices. Initially, lithography using a 157nm wavelength F2 laser was considered promising as the next 45nm node lithography technology, but development delays due to various problems were pointed out. As a result, ArF immersion lithography, which achieves high resolution by inserting a liquid with a refractive index higher than air, such as water, ethylene glycol, or glycerin, between the projection lens and the wafer, allows the numerical aperture (NA) of the projection lens to be designed to be 1.0 or higher. This immersion lithography requires a resist composition that is not easily eluted by water.

[0004] In ArF lithography, highly sensitive resist compositions that can achieve sufficient resolution with low exposure are required to prevent degradation of precise and expensive optical materials. The most common way to achieve this is to select components that are highly transparent at a wavelength of 193 nm. For example, polyacrylic acid and its derivatives, norbornene-maleic anhydride alternating polymers, polynorbornene, ring-opening metathesis polymers, and ring-opening metathesis polymer hydrogenated polymers have been proposed as base polymers, and some success has been achieved in improving the transparency of the resin itself.

[0005] In recent years, negative-tone resists developed using organic solvents have gained attention alongside positive-tone resists developed using alkaline aqueous solutions. To resolve extremely fine hole patterns that cannot be achieved with positive tones, negative patterns are formed by using a high-resolution positive-type resist composition and developing it with an organic solvent. Furthermore, research is underway to obtain twice the resolution by combining two development processes: alkaline aqueous solution development and organic solvent development. Conventional positive-type ArF resist compositions can be used as ArF resist compositions for negative-tone development with organic solvents, and pattern formation methods using such compositions are described in Patent Documents 1 to 3.

[0006] To adapt to the rapid miniaturization of recent years, the development of resist compositions is progressing daily, along with process technologies. Various photoacid generators have been investigated, and sulfonium salts consisting of triphenylsulfonium cations and perfluoroalkanesulfonic acid anions are commonly used. However, the generated acid, perfluoroalkanesulfonic acid, particularly perfluorooctanesulfonic acid (PFOS), is difficult to decompose, bioaccumulates, and poses toxicity concerns, making its application to resist compositions difficult. Currently, photoacid generators that produce perfluorobutanesulfonic acid are used. However, when this is used in resist compositions, the diffusion of the generated acid is large, making it difficult to achieve high resolution. To address this problem, various partially fluorine-substituted alkanesulfonic acids and their salts have been developed. For example, Patent Document 1 describes, as prior art, a photoacid generator that generates α,α-difluoroalkanesulfonic acid upon exposure, specifically a photoacid generator that generates di(4-tert-butylphenyl)iodonium 1,1-difluoro-2-(1-naphthyl)ethanesulfonate and α,α,β,β-tetrafluoroalkanesulfonic acid. However, although the fluorine substitution rate is reduced in all of these, they lack degradable substituents such as ester structures, making them insufficient from the standpoint of environmental safety due to their easy decomposition. Furthermore, there are limitations in molecular design for changing the size of the alkanesulfonic acid, and the starting materials containing fluorine atoms are expensive.

[0007] Furthermore, with the reduction in circuit line width, the effect of contrast degradation due to acid diffusion in resist compositions has become even more serious. This is because the pattern dimensions approach the acid diffusion length, leading to a decrease in mask fidelity and deterioration of pattern rectangularity due to a larger dimensional deviation on the wafer (mask error factor (MEF)) relative to the dimensional deviation of the mask. Therefore, in order to fully obtain the benefits of shorter wavelength and higher NA of the light source, it is necessary to increase the dissolution contrast or suppress acid diffusion more than with conventional materials. As one solution, it is possible to reduce acid diffusion by lowering the bake temperature, and as a result improve the MEF, but this inevitably leads to lower sensitivity.

[0008] Introducing bulky substituents or polar groups into photoacid generators is effective in suppressing acid diffusion. Patent document 4 describes a photoacid generator having 2-acyloxy-1,1,3,3,3-pentafluoropropane-1-sulfonic acid, which has excellent solubility and stability in solvents and allows for a wide range of molecular designs. In particular, photoacid generators having 2-(1-adamantyloxy)-1,1,3,3,3-pentafluoropropane-1-sulfonic acid with bulky substituents exhibit low acid diffusion. Patent documents 5 to 7 also describe photoacid generators with condensed ring lactones, sultones, or thiolactones introduced as polar groups. Although some performance improvement has been confirmed due to the acid diffusion suppression effect of introducing polar groups, it is still insufficient for advanced control of acid diffusion, and the lithography performance is not satisfactory when considering MEF, pattern shape, sensitivity, etc.

[0009] Introducing polar groups into the anion of a photoacid generator is effective in suppressing acid diffusion, but it is disadvantageous from the viewpoint of solvent solubility. Patent documents 8 and 9 describe attempts to improve solvent solubility by introducing alicyclic groups into the cation portion of the photoacid generator, specifically introducing cyclohexane rings and adamantane rings. Although solubility is improved by introducing such alicyclic groups, a certain number of carbon atoms is required to ensure solubility, and as a result the molecular structure of the photoacid generator becomes bulky, which degrades lithography performance such as line width roughness (LWR) and dimensional uniformity (CDU) when forming fine patterns.

[0010] Patent document 10 describes a photoacid generator that produces fluoroalkanesulfonic acid having an aromatic condensed ring derived from anthracene as an anion.

[0011] Because iodine atoms have very high absorption of EUV light at a wavelength of 13.5 nm, the effect of generating secondary electrons from iodine atoms during exposure has been confirmed, and they are attracting attention in EUV lithography. Patent document 11 describes a photoacid generator in which iodine atoms are introduced into an anion, and Patent document 12 describes a photoacid generator containing a polymerizable group in which iodine atoms are introduced into an anion. Patent document 13 describes a photoacid generator in which iodine atoms are introduced into both the cation and the anion. Although some improvement in lithography performance has been confirmed as a result, iodine atoms do not have high solubility in organic solvents, and precipitation in solvents is a concern.

[0012] Patent document 14 describes a photoacid generator in which multiple fluorine atoms are introduced into a cation. Although the introduction of multiple fluorine atoms improves the solvent solubility of the photoacid generator, it is not sufficient from the viewpoint of EUV absorption, and there is room for improvement.

[0013] Patent documents 15-19 describe photoacid generators and quenchers (acid diffusion control agents) containing iodine and fluorine atoms in the cation. While improvements in performance as resist materials have been confirmed through these developments, they are still not satisfactory in terms of acid diffusion control, and there is a need for the development of resist materials that are useful for forming even finer patterns. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] Japanese Patent Publication No. 2008-281974 [Patent Document 2] Japanese Patent Publication No. 2008-281975 [Patent Document 3] Patent No. 4554665 [Patent Document 4] Japanese Patent Publication No. 2007-145797 [Patent Document 5] Patent No. 5061484 [Patent Document 6] Japanese Patent Publication No. 2016-147879 [Patent Document 7] Japanese Patent Publication No. 2015-63472 [Patent Document 8] Patent No. 5573098 [Patent Document 9] Patent No. 6461919 [Patent Document 10] Patent No. 7109178 [Patent Document 11] Patent No. 6720926 [Patent Document 12] Patent No. 6973274 [Patent Document 13] Patent No. 7041204 [Patent Document 14] Patent No. 7389562 [Patent Document 15] Japanese Patent Publication No. 2021-123579 [Patent Document 16] Japanese Patent Publication No. 2021-123580 [Patent Document 17] Japanese Patent Publication No. 2022-123839 [Patent Document 18] Japanese Patent Publication No. 2023-88869 [Patent Document 19] Japanese Patent Publication No. 2023-88870 [Non-patent literature]

[0015] [Non-Patent Document 1] Journal of Photopolymer Science and Technology, Vol. 17, No. 4, p. 587-601 (2004) [Overview of the project] [Problems that the invention aims to solve]

[0016] In response to the recent demand for high-resolution resist patterns, conventional resist compositions using onium salt-type photoacid generators cannot adequately suppress acid diffusion, which can result in a deterioration of lithography performance such as contrast, LWR, CDU, MEF, exposure margin (EL), and depth of field (DOF).

[0017] The present invention has been made in view of the above circumstances, and aims to provide an onium salt used in a chemically amplified resist composition that has excellent solvent solubility, high sensitivity, high contrast, and excellent lithography performance such as LWR, CDU, MEF, EL, DOF, etc., particularly in photolithography using high-energy beams such as KrF excimer laser light, ArF excimer laser light, electron beam (EB), and EUV; a chemically amplified resist composition containing the onium salt as a photoacid generator; and a method for forming a pattern using the chemically amplified resist composition. [Means for solving the problem]

[0018] As a result of diligent research to achieve the above objective, the present inventors have discovered that a sulfonium salt comprising a fluoroalkanesulfonic acid anion without polymerizable groups and a sulfonium cation having a pentafluorosulfanil group and an acid-unstable group having a tertiary / secondary ether structure, a tertiary / secondary carbonate structure, or an acetal structure exhibits excellent solvent solubility, and that a chemically amplified resist composition using this as a photoacid generator exhibits high sensitivity and high contrast, is extremely effective in suppressing acid diffusion, has excellent lithography performance such as LWR, CDU, MEF, EL, and DOF, and is extremely effective in forming fine patterns, leading to the present invention.

[0019] In other words, the present invention provides the following sulfonium salts, chemically amplified resist compositions, and pattern formation methods. 1. A sulfonium salt represented by the following formula (1). [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 3is, independently of each other, a halogen atom, a nitro group, a cyano 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 1 may be the same as or different from each other, and two R 1 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 2 may be the same as or different from each other, and two R 2 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 3 may be the same as or different from each other, and two R 3 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. R AL1 、R AL2 and R AL3 are, independently of each other, acid-labile groups. When n3 is 2, each R AL1 may be the same as or different from each other. When n7 is 2, each R AL2 may be the same as or different from each other. When n11 is 2, each R AL3 may be the same as or different from each other. At least one -SF5 group is bonded to a carbon atom adjacent to the carbon atom to which -O-R AL1 , -O-R AL2 or -O-R AL3 is bonded. Also, two of the three aromatic rings bonded to S + may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Z - is a fluoroalkanesulfonic acid anion having no polymerizable group.) 2. The sulfonium salt of 1 represented by the following formula (1A).

Chemical formula

Chemical formula

[0020] When pattern formation is performed using a chemically amplified resist composition containing the sulfonium salt of the present invention as a photoacid generator, it exhibits high sensitivity, excellent acid diffusion suppression ability, improved lithography performance such as LWR, CDU, MEF, EL, and DOF, and suppression of resist pattern deformation during fine pattern formation. [Modes for carrying out the invention]

[0021] The present invention will be described in detail below. In the following description, depending on the structure represented by the chemical formula, an asymmetric carbon may be present, and enantiomers or diastereomers may exist. In such cases, one formula will represent all of these isomers. These isomers may be used individually or as a mixture of two or more.

[0022] [Sulfonium salt] The sulfonium salt of the present invention is represented by the following formula (1). [ka]

[0023] In formula (1), 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.

[0024] In formula (1), 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.

[0025] In formula (1), 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.

[0026] In equation (1), 1 ≤ n² + n⁶ + n⁰ ≤ 6, but preferably 1 ≤ n² + n⁶ + n⁰ ≤ 3, and even more preferably 1 ≤ n² + n⁶ + n⁰ ≤ 2. Also, 1 ≤ n⁷ + n⁰ ≤ 6, but preferably 1 ≤ n⁷ + n⁰ ≤ 3, and even more preferably 1 ≤ n⁷ + n⁰ ≤ 2.

[0027] In formula (1), R 1 , R 2 and R 3Each of these is independently a halogen atom, a nitro group, a cyano 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- 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.

[0028] When n4 is 2, each R 1 These may be the same or different from each other. Also, when n4 is 2, the two R 1 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 2 These may be the same or different from each other. Also, when n8 is 2, the two R 2 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 n12 is 2, each R 3 These may be the same or different from each other. Also, when n12 is 2, the two R 3 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.

[0029] In formula (1), R AL1 , R AL2 and R AL3 These are each an acid-unstable group independently. When n3 is 2, each R AL1 These may be the same or different from each other. When n7 is 2, each R AL2 These may be the same or different from each other. When n11 is 2, each R AL3 They may be the same as or different from each other.

[0030] The acid-unstable group is preferably one represented by the following formula (AL-1) or (AL-2). [ka] (In the formula, * represents a bond.)

[0031] In equations (AL-1) and (AL-2), m1 and m2 are independently either 0 or 1.

[0032] In formula (AL-1), R L1 and R L2 These are, independently, hydrocarbyl groups having 1 to 12 carbon atoms. L3 R is a hydrogen atom or a hydrocarbyl group having 1 to 12 carbon atoms. L1 , R L2 and R L3 A portion of the -CH2- in the hydrocarbyl group represented by 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 , R L2 and R L3 The hydrocarbyl group, represented by , having 1 to 12 carbon atoms, can be saturated or unsaturated, and can be linear, branched, or cyclic. A specific example is R 1 , R 2 and R 3 Among the examples of hydrocarbyl groups represented by , those with 1 to 12 carbon atoms are listed. 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-. However, R L3 If it is a hydrogen atom, R L1 and R L2 These atoms bond to each other, forming an alicyclic ring containing multiple bonds with the carbon atoms to which they bond.

[0033] 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 1 , R 2 and R 3 Among the examples of hydrocarbyl groups represented by , those with 1 to 10 carbon atoms are similar to those shown. 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. A 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-. L6 The hydrocarbyl group, represented by , having 1 to 20 carbon atoms, can be saturated or unsaturated, and can be linear, branched, or cyclic. A specific example is R 1 , R 2 and R 3 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0034] In formula (AL-2), L A It is either -O- or -S-.

[0035] 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 -O-. [ka]

[0036] [ka]

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[0055] [Chemical] [[ID=​​​​​​​​​​​​​​ [ka]

[0058] [ka]

[0059] In equation (1), at least one -SF5 group is -OR AL1 , -OR AL2 OR AL3 It is bonded to a carbon atom adjacent to the carbon atom to which it is bonded. -SF5 group and -OR AL1 , -OR AL2 OR AL3 The bond between these two carbon atoms to adjacent carbon atoms results in -R AL1 , -R AL2 or -R AL3 The acidity of phenols improves after deprotection, and the solubility contrast is enhanced.

[0060] 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.)

[0061] The sulfonium salt represented by formula (1) is preferably the one represented by formula (1A) below. [ka] (In the formula, n2~n4, n6~n8, n10~n12, R AL1 ~R AL3 and R 1 ~R 3 The same as above. Z - (This will be explained later.)

[0062] Specific examples of cations of sulfonium salts represented by formula (1) are listed below, but are not limited to these. In the following formulas, Me represents a methyl group. [ka]

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[0423] [ka]

[0424] [ka]

[0425] In equations (1) and (1A), Z - This is a fluoroalkanesulfonic acid anion that does not have a polymerizable group. The fluoroalkanesulfonic acid anion is preferably one that is represented by any of the following formulas (Z-1) to (Z-3). [ka]

[0426] In formula (Z-1), R 11 R is a hydrocarbyl group having 1 to 60 carbon atoms, 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 (Z-1-1) described later. 11a Examples 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 atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, 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.

[0427] The anion represented by formula (Z-1) is preferably the one represented by the following formula (Z-1-1). [ka]

[0428] In formula (Z-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 11a This is a hydrocarbyl group having 1 to 40 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.

[0429] In formula (Z-1-1), R 11aThe C1-C40 hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C40 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, norbornylmethyl, tricyclodecyl, tetracyclododecyl, and tetracyclo Examples include cyclic saturated hydrocarbyl groups with 3 to 40 carbon atoms, such as dodecylmethyl and dicyclohexylmethyl groups; aryl groups with 6 to 40 carbon atoms, such as phenyl, 1-naphthyl, 2-naphthyl, 9-fluorenyl, and triptycenyl groups; aralkyl groups with 7 to 40 carbon atoms, such as benzyl and diphenylmethyl groups; aromatic ring-containing polycyclic hydrocarbyl groups with 7 to 40 carbon atoms, such as 9,10-ethano-9,10-dihydroanthryl and 6,13-ethano-6,13-dihydropentacenyl groups; hydrocarbyl groups with 17 to 40 carbon atoms having a steroid skeleton; and groups obtained by combining these.

[0430] 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.

[0431] In formula (Z-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.

[0432] In formula (Z-2), R 12 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 (Z-1-1). 11aExamples 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 atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, 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.

[0433] In equation (Z-3), x is 1, 2, or 3. y is 1, 2, 3, 4, or 5. z is 0, 1, 2, or 3, where 1 ≤ y + z ≤ 5. y is preferably 1, 2, or 3, more preferably 2 or 3. z is preferably 0, 1, or 2.

[0434] In formula (Z-3), X BI is an iodine atom or a bromine atom. When x and / or y are 2 or more, each X BI They may be the same as or different from each other.

[0435] In formula (Z-3), L 1 This is a single bond, ether bond, ester bond, sulfonic acid ester bond, carbonate bond, carbamate bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms, and a portion of the -CH2- of the hydrocarbylene group may be substituted with an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0436] In formula (Z-3), L 2 When x is 1, it is a C1-C20 hydrocarbylene group which may contain a single bond or a heteroatom, and when x is 2 or 3, it is a C1-C20 (x+1) valent hydrocarbon group which may contain a heteroatom.

[0437] L2 The C1-C20 hydrocarbylene group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C20 alkanediyl groups such as methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl; cyclopentanediyl, cyclohexanediyl, norbornanediyl, adamantanediyl, tricyclo[5.2.1.0 2,6 Examples include cyclic saturated hydrocarbylene groups with 3 to 20 carbon atoms, such as decanediyl groups; unsaturated aliphatic hydrocarbylene groups with 2 to 20 carbon atoms, such as vinylene groups and propene-1,3-diyl groups; arylene groups with 6 to 20 carbon atoms, such as phenylene groups, naphthylene groups, and anthracenediyl groups; aromatic ring-containing polycyclic hydrocarbylene groups with 7 to 20 carbon atoms, such as 9,10-ethano-9,10-dihydroanthracenediyl groups and 6,13-ethano-6,13-dihydropentacene groups; and groups obtained by combining these. 2 The (x+1) valent hydrocarbon group having 1 to 20 carbon atoms, represented by , may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include groups obtained by removing one or two hydrogen atoms from the aforementioned specific examples of the 1 to 20 carbon atom hydrocarbylene group.

[0438] Furthermore, some or all of the hydrogen atoms of the hydrocarbylene group and the (x+1) valent hydrocarbon 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 and the (x+1) valent hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, the material 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.

[0439] In formula (Z-3), L 3 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, or carbamate bonds.

[0440] In formula (Z-3), R 13 This includes a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom, a pentafluorosulfanyl group, an amino group, a C1-C20 hydrocarbyl group, a C1-C20 hydrocarbyloxy group, a C1-C20 hydrocarbylthio group, a C2-C20 hydrocarbylcarbonyl group, a C2-C20 hydrocarbyloxycarbonyl group, a C2-C20 hydrocarbylcarbonyloxy group, a C1-C20 hydrocarbylsulfonyloxy group, and -N(R 13A )(R 13B ), -N(R 13C )-C(=O)-R 13D or -N(R 13C )-C(=O)-OR 13D The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylthio group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may contain at least one selected from fluorine, chlorine, bromine, iodine, hydroxyl, amino, ester, and ether bonds. 13A and R 13BEach of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 13C 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. 13D 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 x and / or z is 2 or more, each R 13 They may be the same as or different from each other.

[0441] Of these, R 13 Examples include hydroxyl groups, -N(R 13C )-C(=O)-R 13D , -N(R 13C )-C(=O)-OR 13D Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc. are preferred.

[0442] In formula (Z-3), Rf 1 ~Rf 4 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 1 and Rf 2 These may combine to form a carbonyl group. In particular, Rf 3 and Rf 4 It is preferable that both are fluorine atoms.

[0443] Specific examples of anions represented by formula (Z-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]

[0444] [ka]

[0445] [ka]

[0446] [ka]

[0447] [ka]

[0448] [ka]

[0449] [ka]

[0450] [ka]

[0451] [ka]

[0452]

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[0457]

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[0460]

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[0461]

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[0462]

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[0463] Specific examples of anions represented by formula (Z-2) are listed below, but are not limited to these. [ka]

[0464] [ka]

[0465] [ka]

[0466] [ka]

[0467] [ka]

[0468] [ka]

[0469] [ka]

[0470] [ka]

[0471] [ka]

[0472] [ka]

[0473] Specific examples of anions represented by formula (Z-3) 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]

[0474] [ka]

[0475] [ka]

[0476] [ka]

[0477] [ka]

[0478] [ka]

[0479] [ka]

[0480] [ka]

[0481] [ka]

[0482] [ka]

[0483]

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[0498] Z -Other examples of anions represented by include paragraphs

[0076] and

[0106] of International Publication No. 2023 / 157455, paragraph

[0111] of International Publication No. 2024 / 24801, paragraphs

[0253] to

[0256] of International Publication No. 2024 / 43121, paragraphs

[0044] to

[0045] of International Publication No. 2024 / 57751, paragraphs

[0205] to

[0220] of International Publication No. 2024 / 122423, paragraphs

[0170] to

[0178] of Japanese Patent Publication No. 2023-123183, and paragraphs

[0026] to

[0028] of Japanese Patent Publication No. 2024-62406. Paragraphs

[0022] to

[0025] of JP 2024-62407, paragraphs

[0026] to

[0028] of JP 2024-62408, paragraphs

[0028] to

[0030] of JP 2024-68156, paragraphs

[0026] to

[0028] of JP 2024-68157, paragraphs

[0028] to

[0030] of JP 2024-68158, paragraphs

[0028] to

[0030] of JP 2024-68159, paragraphs

[0031] to

[0033] of JP 2024-72280, paragraph

[0023] of JP 2024-72281 Paragraphs

[0026] to

[0029] of JP 2024-77618, paragraphs

[0020] to

[0021] of JP 2024-77619, paragraphs

[0140] to

[0143] of JP 2024-80672, paragraphs

[0023] to

[0025] of JP 2024-83303, paragraphs

[0028] to

[0031] of JP 2024-83304, paragraphs

[0030] to

[0033] of JP 2024-99500, paragraphs

[0028] to

[0030] of JP 2024-99502, and JP 2024-101557 Paragraphs

[0030] to

[0032] of the publication, paragraphs

[0025] to

[0027] of JP 2024-102842 A, paragraphs

[0033] to

[0035] of JP 2024-102843 A, paragraphs

[0021] to

[0022] of JP 2024-127832 A, paragraphs

[0169] to

[0172] of JP 2024-144354 A, paragraphs

[0178] to

[0181] of JP 2024-144356 A, paragraphs

[0040] to

[0143] of JP 2024-160436 A, paragraphs

[0157] to

[0158] of Patent No. 7247732,Examples include those described in paragraphs

[0227] to

[0238] of Japanese Patent Publication No. 7446352, paragraphs

[0253] to

[0256] of Japanese Patent Publication No. 7466597, and paragraphs

[0309] to

[0312] of Japanese Patent Publication No. 7466782.

[0499] Specific examples of the sulfonium salt of the present invention include any combination of the anion and cation described above.

[0500] Methods for synthesizing the sulfonium salt of the present invention include those described in Japanese Patent Publication No. 2010-155824 and Japanese Patent No. 7067271, but these manufacturing methods are merely examples, and the method for producing the sulfonium salt of the present invention is not limited to these.

[0501] The structural features of the sulfonium salt of the present invention include having a fluoroalkanesulfonic acid anion that does not have polymerizable groups, and a sulfonium cation having a pentafluorosulfanil group and an acid-unstable group having a tertiary / secondary ether structure, a tertiary / secondary carbonate structure, or an acetal structure. It is known that secondary electrons are released when the base polymer or photoacid generator is irradiated with EUV light, but the pentafluorosulfanil group of the sulfonium cation lowers the energy level of the lowest empty molecular orbital (LUMO) in frontier orbital theory due to the electron-withdrawing effect, making it easier to accept the generated secondary electrons, thereby promoting the decomposition of the cation and effectively generating acid. In addition, the acid-unstable group having a tertiary / secondary ether structure, a tertiary / secondary carbonate structure, or an acetal structure substituted on the aromatic ring of the sulfonium cation undergoes a deprotection reaction with the acid generated by exposure, producing the corresponding phenols. The change in structure from lipophilic to hydrophilic improves the contrast between the exposed and unexposed areas. Furthermore, when a pentafluorosulfanil group is bonded to a carbon atom adjacent to the carbon atom to which the generated phenolic hydroxyl group is bonded, the electron-withdrawing properties of the pentafluorosulfanil group increase the acidity of the phenols. When developing the exposed area, to which the deprotection reaction has progressed, with an alkaline developer, the increased acidity of the phenols improves their solubility in the alkaline developer, thereby suppressing development residue. Additionally, swelling caused by the alkaline developer is suppressed, which helps to prevent the resist pattern from collapsing.

[0502] In the sulfonium salt of the present invention, the fluoroalkanesulfonic acid anion that does not have polymerizable groups preferably has a cyclic structure or one or more iodine atoms. Introducing a cyclic structure results in a large excluded volume and acts as a bulky substituent, highly suppressing the diffusion of generated acid. When iodine atoms are introduced, they are an element with a high absorption effect of EUV light, so the amount of secondary electrons generated increases, promoting cation decomposition and contributing to higher sensitivity. Also, since iodine atoms are an element with a large molecular weight, they highly suppress the diffusion of generated acid, similar to the case of introducing a cyclic structure. Furthermore, since cyclic structures and iodine atoms are resistant to alkaline developers, they reduce film loss in the unexposed areas. Although not as much as iodine atoms, fluorine atoms in the fluoroalkanesulfonic acid anion have a high absorption effect of EUV light, so increasing the number of fluorine atoms increases the amount of secondary electrons generated, promoting cation decomposition and contributing to higher sensitivity. While the introduction of cyclic structures or iodine atoms raises concerns about solvent solubility, the multiple fluorine atoms in the anion and the acid-unstable groups in the sulfonium cation ensure sufficient solvent solubility, allowing for uniform dissolution in solvents and reducing concerns about precipitation during storage. Due to these synergistic effects, the resist composition containing the sulfonium salt of the present invention exhibits high sensitivity and low acid diffusivity, resulting in excellent lithography performance such as LWR and CDU, and enabling the formation of patterns resistant to pattern deformation, making it suitable for fine pattern formation.

[0503] The sulfonium salt of the present invention can be suitably used as a photoacid generator.

[0504] [Chemically amplified resist composition] [(A) Photoacid Generator] The chemically amplified resist composition of the present invention contains a photoacid generator comprising a sulfonium salt represented by formula (1) as an essential component.

[0505] In the chemically amplified resist composition of the present invention, the content of the photoacid generator consisting of a sulfonium salt of component (A) 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 component (A) 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. The photoacid generator (A) may be used alone or in combination of two or more types.

[0506] [(B) Base polymer] The chemically amplified resist composition of the present invention may contain a base polymer as component (B). The base polymer (B) is preferably one that contains repeating units having an acid-unstable group. The repeating units containing the acid-unstable group may be used individually or in combination of two or more types.

[0507] Specific examples of repeating units containing the aforementioned acid-unstable group include the repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1) and the repeating unit represented by the following formula (a2) (hereinafter also referred to as repeating unit a2). [ka]

[0508] In equations (a1) and (a2), R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0509] In formula (a1), X 1 This refers to a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OX 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. 11This 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.

[0510] In formula (a2), X 2 The bond is either a single bond or *-C(=O)-O-. * represents a bond with a carbon atom in the main chain. 21 is a halogen atom, a cyano group, a hydroxyl group, a nitro group, a pentafluorosulfanil group, a C1-C20 hydrocarbyl group which may contain 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. a1 is 0, 1, 2, 3, or 4, preferably 0 or 1. When a1 is 2, 3, or 4, each R 21 They may be the same as or different from each other.

[0511] In formulas (a1) and (a2), AL 1 and AL 2 Each of these is independently an acid-unstable group. Specific examples of the acid-unstable groups include those described in Japanese Patent Publication No. 2013-80033 and Japanese Patent Publication No. 2013-83821.

[0512] Typical examples of the acid-unstable groups include those represented by the following formulas (AL-3) to (AL-5). [ka] (In the formula, * represents a coupling.)

[0513] In equations (AL-3) and (AL-4), R L11 and R L12Each 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.

[0514] In formula (AL-3), a2 is an integer between 0 and 10, preferably 1, 2, 3, 4, or 5.

[0515] 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.

[0516] 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.

[0517] 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.

[0518] 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]

[0519] [ka]

[0520] [ka]

[0521] [ka]

[0522] 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]

[0523] [ka]

[0524] [ka]

[0525] Another specific example of a repeating unit containing the aforementioned acid-unstable group is the repeating unit represented by the following formula (a3) ​​(hereinafter also referred to as repeating unit a3). [ka]

[0526] 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.

[0527] 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.

[0528] In formula (a3), X 3 The bond is a single bond, *-C(=O)-O-, or *-C(=O)-N(H)-. * 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.

[0529] 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.

[0530] 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.

[0531] In formula (a3), R 22 and R 23Each 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.

[0532] Also, R 22 and R 23These 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.

[0533] In formula (a3), R 24 This may include halogen atoms, hydroxyl groups, cyano groups, nitro groups, pentafluorosulfanyl groups, C1-C20 hydrocarbyl groups which may contain heteroatoms, C1-C20 hydrocarbyloxy groups which may contain heteroatoms, C2-C20 hydrocarbyloxycarbonyl groups which may contain heteroatoms, C1-C20 hydrocarbylthio groups which may contain heteroatoms, or -N(R 24A )(R 24B ) is R 24A and R 24B 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 22 and R 23Examples 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 24 They may be the same as or different from each other.

[0534] Also, when b2 is 2 or more, multiple R 24 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.

[0535] 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]

[0536]

change

[0537]

change

[0538]

change

[0539]

change

[0540]

change

[0541]

change

[0542]

change

[0543]

change

[0544]

change

[0545]

change

[0546]

change

[0547]

change

[0548]

change

[0549]

change

[0550]

change

[0551]

change

[0552]

change

[0553]

change

[0554]

change

[0555]

change

[0556]

change

[0557]

change

[0558]

change

[0559]

change

[0560]

change

[0561]

change

[0562]

change

[0563]

change

[0564]

change

[0565]

change

[0566]

change

[0567]

change

[0568]

change

[0569]

change

[0570]

change

[0571]

change

[0572]

change

[0573]

change

[0574]

change

[0575]

change

[0576]

change

[0577]

change

[0578] [ka]

[0579] [ka]

[0580] [ka]

[0581] [ka]

[0582] [ka]

[0583] [ka]

[0584] [ka]

[0585] The polymer may contain 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]

[0586] 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.31 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)-). 32 This is a halogen atom, a carboxyl group, a nitro group, a cyano group, a pentafluorosulfanil group, a C1-C20 hydrocarbyl group which may contain 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 32 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.

[0587] 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]

[0588] [ka]

[0589] [ka]

[0590] [ka]

[0591]

change

[0592]

change

[0593]

change

[0594]

change

[0595]

change

[0596]

change

[0597]

change

[0598]

change

[0599]

change

[0600]

change

[0601]

change

[0602] [ka]

[0603] 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]

[0604] [ka]

[0605] [ka]

[0606] [ka]

[0607] [ka]

[0608] 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.

[0609] 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]

[0610] 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)-N(H)-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, sulfonic acid ester bonds, amide 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 These are, independently, a single bond, an optionally substituted phenylene group, an optionally substituted naphthylene group, and *-C(=O)-OZ 51 -or *-C(=O)-N(R)-Z 51 - is Z 51R is an aliphatic hydrocarbylene group, phenylene group, or 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. R is a hydrocarbyl group having 1 to 10 carbon atoms, which may contain a hydrogen atom or a heteroatom. Z 6 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, amide bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. 7 Each of these is independently a single bond, ***-Z 71 -C(=O)-O-, ***-C(=O)-N(R)-Z 71 -or ***-OZ 71 - is. is. Z 71 R is a hydroxylene group having 1 to 20 carbon atoms, which may contain heteroatoms. R is the same as described above. Z 8 These are, independently, single bonds, ****-Z 81 -C(=O)-O-, ****-C(=O)-N(R)-Z 81 -or ****-OZ 81 - is Z 81 R is a hydroxylene group having 1 to 20 carbon atoms, which may contain heteroatoms. R is the same as described above. 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(R)-Z 91 -or *-OZ 91 - is Z 91 R 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. R is the same as above. * 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.

[0611] Z 21 , Z 51 and Z 91 The 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.

[0612] 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.)

[0613] In formula (c1), R 41 and R 42Each 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.

[0614] Also, R 41 and R 42 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.)

[0615] 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]

[0616] [ka]

[0617] [ka]

[0618] [ka]

[0619] [ka]

[0620] [ka]

[0621] [ka]

[0622] [ka]

[0623] [ka]

[0624] [ka]

[0625] 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.

[0626] Other examples of the aforementioned non-nucleophilic counterions include anions represented by any of the formulas (Z-1) to (Z-3).

[0627] Other examples of the non-nucleophilic counterions include anions represented by the following formulas (M-1) or (M-2). [ka]

[0628] In formula (M-1), R M1 and R M2Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each 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 (Z-1-1). 11a Examples of hydrocarbyl groups represented by R include those similar to those exemplified. M1 and R M2 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. M1 and R M2 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 M1 and R M2 The groups obtained by the bonding of these groups are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0629] In formula (M-2), R M3 , R M4 and R M5 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each 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 (Z-1-1). 11a Examples of hydrocarbyl groups represented by R include those similar to those exemplified. M3 , R M4 and R M5 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. M3 and R M4 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 M3 and R M4 The groups obtained by the bonding of these groups are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0630] 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.

[0631] In formulas (c2) and (c3), d1 and d2 are independently 0, 1, 2, or 3, but 1 is preferred.

[0632] 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.

[0633] In equations (c2), (c3), and (c4), L 1 These 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.

[0634] In formula (c2), Rf 11 and Rf 12 Each of these is independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Of these, Rf 11 and Rf 12 To increase the acid strength of the generated acid, it is preferable that all atoms be fluorine atoms. Rf 13 and Rf 14 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. 13 and Rf 14 At least one of them is preferably a trifluoromethyl group.

[0635] In formula (c3), Rf 15 and Rf 16 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 15 and Rf 16 These cannot simultaneously become hydrogen atoms. Of these, Rf 15 and Rf 16 At least one of them is preferably a trifluoromethyl group.

[0636] In formula (c4), Rf 17 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, a fluorinated alkylthio group having 1 to 6 carbon atoms, or a pentafluorosulfanil group. 17 Preferably, 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 17 They may be the same as or different from each other.

[0637] In formula (c4), R 43 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 (1), 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 43 They may be the same as or different from each other.

[0638] Also, when e3 is 2, 3, or 4, multiple R 43These 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.

[0639] 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]

[0640] [ka]

[0641] [ka]

[0642] [ka]

[0643] [ka]

[0644] [ka]

[0645] [ka]

[0646] [ka]

[0647] [ka]

[0648] [ka]

[0649] [ka]

[0650] [ka]

[0651] [ka]

[0652] Other specific examples of repeating unit c2 include those described in paragraphs

[0043] to

[0044] of International Publication No. 2024 / 176672, paragraphs

[0067] to

[0070] of International Publication No. 2024 / 176701, paragraphs

[0057] to

[0058] of International Publication No. 2024 / 190386, paragraphs

[0020] to

[0023] of Japanese Patent Application Publication No. 2024-103465, paragraphs

[0067] to

[0070] of Japanese Patent Application Publication No. 2024-120703, and paragraphs

[0075] to

[0084] of Japanese Patent No. 7520258.

[0653] 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]

[0654] [ka]

[0655] [ka]

[0656] [ka]

[0657] [ka]

[0658] [ka]

[0659] [ka]

[0660] [ka]

[0661] [ka]

[0662] [ka]

[0663] [ka]

[0664] 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]

[0665] [ka]

[0666] [ka]

[0667] [ka]

[0668] [ka]

[0669] [ka]

[0670] [ka]

[0671] [ka]

[0672] [ka]

[0673] [ka]

[0674] [ka]

[0675] [ka]

[0676] [ka]

[0677] [ka]

[0678] [ka]

[0679] [ka]

[0680] [ka]

[0681] 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]

[0682] 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 cations of sulfonium salts represented by formula (1), 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.

[0683] Furthermore, a sulfonium cation represented by the following formula (sulfo-1) is also preferred as the sulfonium cation. [ka]

[0684] 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.

[0685] 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.

[0686] 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.

[0687] 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.

[0688] 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.

[0689] 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.

[0690] 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.

[0691] 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.

[0692] 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 F2 They 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.

[0693] 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 (1), R 1 ~R 3Examples 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.

[0694] 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. ct2 These 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. ct4These 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.

[0695] 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.)

[0696] In the formula (sulfo-1), L B and L C These are, independently, a single bond, an ether bond, an ester bond, a sulfonic acid ester bond, an amide bond, a sulfonic acid amide bond, a carbonate bond, or a carbamate bond. Of these, L B The 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. C The bond is preferably a single bond, an ether bond, or an ester bond, and more preferably a single bond.

[0697] In the formula (sulfo-1), XL 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.

[0698] 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 B and L C This is a combination of the two. [ka]

[0699] [ka]

[0700] [ka]

[0701] [ka]

[0702] Of these, X L -0~X L -22, X L -29~X L -34, and X L -47~X L -61 is preferred.

[0703] 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 B , L C and X L (This is the same as above.)

[0704] 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.)

[0705] 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]

[0706] [ka]

[0707] [ka]

[0708] [ka]

[0709] [ka]

[0710]

change

[0711]

change

[0712]

change

[0713]

change

[0714]

change

[0715]

change

[0716]

change

[0717]

change

[0718]

change

[0719]

change

[0720]

change

[0721]

change

[0722]

change

[0723]

change

[0724]

change

[0725]

change

[0726]

change

[0727]

change

[0728]

change

[0729]

change

[0730]

change

[0731] [ka]

[0732] [ka]

[0733] 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.

[0734] 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 (1). 1 ~R 3 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0735] Specific examples of ammonium cations represented by formula (am-1) are listed below, but are not limited to these. [ka]

[0736] The specific structures of the repeating units c1 to c5 include any combination of the anions and cations mentioned above.

[0737] 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.

[0738] 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]

[0739] In formula (d1), R A R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 51 R is a (g+1) valent hydrocarbon group having 1 to 30 carbon atoms, which may contain heteroatoms. 52 g is an acid-unstable group. g is 1, 2, 3, or 4.

[0740] In formula (d1), R 52 The acid-unstable group represented by can be any group that is deprotected by the action of an acid and generates a hydroxyl group. 52 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. R 53 (This refers to a hydrocarbyl group with 1 to 15 carbon atoms.)

[0741] R 52Examples of the acid-labile group represented by the formula, the hydrocarbyloxymethyl group represented by the formula (d2), and the repeating unit d are the same as those exemplified in the description of the repeating unit d described in JP-A-2020-111564.

[0742] The polymer may contain a repeating unit e derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or a derivative thereof. Specific examples of the monomer that gives the repeating unit e include, but are not limited to, those shown below. [Chemical formula]

[0743] The polymer may contain a repeating unit f derived from indane, vinylpyridine, or vinylcarbazole.

[0744] In the polymer, the content ratios of the repeating units a1, a2, a3, b1, b2, c1 to c5, d, e, and f are preferably 0 < a1 ≤ 0.8, 0 ≤ a2 ≤ 0.8, 0 ≤ a3 ≤ 0.6, 0 ≤ b1 ≤ 0.6, 0 ≤ b2 ≤ 0.6, 0 ≤ c1 ≤ 0.4, 0 ≤ c2 ≤ 0.4, 0 ≤ c3 ≤ 0.4, 0 ≤ c4 ≤ 0.4, 0 ≤ c5 ≤ 0.4, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.3, and 0 ≤ f ≤ 0.3, and more preferably 0 < a1 ≤ 0.7, 0 ≤ a2 ≤ 0.7, 0 ≤ a3 ≤ 0.5, 0 ≤ b1 ≤ 0.5, 0 ≤ b2 ≤ 0.5, 0 ≤ c1 ≤ 0.3, 0 ≤ c2 ≤ 0.3, 0 ≤ c3 ≤ 0.3, 0 ≤ c4 ≤ 0.3, 0 ≤ c5 ≤ 0.3, 0 ≤ d ≤ 0.3, 0 ≤ e ≤ 0.3, and 0 ≤ f ≤ 0.3. However, a1 + a2 + a3 + b1 + b2 + c1 + c2 + c3 + c4 + d + e + f ≤ 1.0.

[0745] 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.

[0746] 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.

[0747] 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.

[0748] 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.

[0749] 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.

[0750] 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.

[0751] 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.

[0752] 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.

[0753] 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.

[0754] 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.

[0755] 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.

[0756] 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.

[0757] 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.

[0758] 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.

[0759] (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.

[0760] [(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.

[0761] 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).

[0762] 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.

[0763] [(D) Quencher] The chemical amplification resist composition of the present invention may contain a quencher as component (D). In the present invention, a quencher is a material that traps the strong acid generated from the photoacid generator in the chemical amplification resist composition, thereby preventing its diffusion to unexposed areas and forming a desired pattern. A strong acid means an acid that has sufficient acidity to cause a deprotection reaction of acid-unstable groups.

[0764] (D) Specific examples of quenchers include onium salts represented by the following formulas (2) or (3). [ka]

[0765] In formula (2), 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 (3), R q2 This is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a hydrogen atom or a heteroatom.

[0766] 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 2,6Examples 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, resulting in the inclusion of 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.

[0767] 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.

[0768] Specific examples of anions of onium salts represented by formula (2) are listed below, but are not limited to these. [ka]

[0769] [ka]

[0770] [ka]

[0771] [ka]

[0772] [ka]

[0773] Specific examples of anions of onium salts represented by formula (3) are listed below, but are not limited to these. [ka]

[0774] [ka]

[0775] [ka]

[0776] [ka]

[0777] [ka]

[0778] In equations (2) and (3), 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 specific examples of cations of sulfonium salts represented by formula (1), 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 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 specific examples of ammonium cations represented by formula (am-1).

[0779] Specific examples of onium salts represented by formula (2) or (3) 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.

[0780] The onium salt represented by formula (2) or (3) acts as a quencher 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 means one that exhibits an acidity that cannot deprotect the acid-unstable groups of the acid-unstable group-containing units used in the base polymer. The onium salt represented by formula (2) or (3) functions as a quencher when used in combination with an onium salt type photoacid generator having a conjugate base of a strong acid, such as a sulfonic acid with fluorinated α-position, as a counteranion. That is, when an onium salt that generates a strong acid, such as a sulfonic acid with fluorinated α-position, is mixed with an onium salt that generates a weak acid, such as an unfluorinated sulfonic acid or carboxylic acid, 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, strong acids are replaced by weaker acids with lower catalytic activity, so the acids appear to be deactivated, allowing for control of acid diffusion.

[0781] Furthermore, as the (D) quencher, 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 can also be used.

[0782] 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.

[0783] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (2) or (3) as a (D) quencher, its content 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 (B) base polymer. 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 (2) or (3) may be used alone or in combination of two or more types.

[0784] The chemically amplified resist composition of the present invention may contain a nitrogen-containing compound as (D) 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.

[0785] 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.

[0786] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as (D) quencher, the content 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 (B) base polymer. The nitrogen-containing compound may be used alone or in combination of two or more.

[0787] [(E) Other photoacid generators] The chemically amplified resist composition of the present invention may contain a photoacid generator other than component (A) (hereinafter also referred to as "other photoacid generator") as component (E). The other photoacid generator is not particularly limited as long as it is a compound that generates a strong acid upon irradiation with high-energy rays. Suitable other photoacid generators include those represented by the following formulas (4) or (5). [ka]

[0788] In equations (4) and (5), 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 (1). 1 ~R 3 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0789] Specific examples of sulfonium salt cations represented by formula (4) include, but are not limited to, those exemplified as specific examples of sulfonium salt cations represented by formula (1), 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 (5) include, but are not limited to, those described in paragraph

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

[0790] In equations (4) and (5), Xa -This is a strong acid anion. Preferred strong acid anions are the anion represented by formula (Z-1), the anion represented by formula (Z-2), the anion represented by formula (Z-3), the anion represented by formula (M-1), and the anion represented by formula (M-2).

[0791] Furthermore, as an additional photoacid generator for component (E), one represented by the following formula (6) is also preferred. [ka]

[0792] In formula (6), 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.

[0793] 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.

[0794] 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.

[0795] In formula (6), 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.

[0796] In formula (6), 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.

[0797] The photoacid generator represented by formula (6) is preferably the one represented by formula (6') below. [ka]

[0798] In formula (6'), 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 (Z-1-1). 11a Examples of hydrocarbyl groups represented by the formula are similar to those exemplified. p and q are independently 0, 1, 2, 3, 4, or 5, and r is 0, 1, 2, 3, or 4.

[0799] Specific examples of the photoacid generator represented by formula (6) include those similar to those exemplified as the photoacid generator represented by formula (2) in Japanese Patent Publication No. 2017-26980.

[0800] Among the other photoacid generators mentioned above, those containing anions represented by formula (Z-1-1) or (Z-4) are particularly preferred because they exhibit low acid diffusion and excellent solubility in solvents. Furthermore, those represented by formula (6') are particularly preferred because they exhibit extremely low acid diffusion.

[0801] If the chemically amplified resist composition of the present invention contains (E) other photoacid generators, the content thereof 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 photoacid generator added to component (E) 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. (E) Other photoacid generators may be used alone or in combination of two or more types.

[0802] [(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.

[0803] 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]

[0804] 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.)

[0805] Among these, the 1,4-butylene group and the 2,2-dimethyl-1,3-propylene group are preferred.

[0806] 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.

[0807] 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.

[0808] Specific examples of such polymer-type surfactants include those containing at least one selected from the following repeating units: the repeating unit represented by formula (7A) (hereinafter also referred to as repeating unit 7A), the repeating unit represented by formula (7B) (hereinafter also referred to as repeating unit 7B), the repeating unit represented by formula (7C) (hereinafter also referred to as repeating unit 7C), the repeating unit represented by formula (7D) (hereinafter also referred to as repeating unit 7D), and the repeating unit represented by formula (7E) (hereinafter also referred to as repeating unit 7E). [ka]

[0809] 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. s1 Each 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. s3If 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.

[0810] 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.

[0811] 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.

[0812] R s3 or R s6The 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.

[0813] 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.

[0814] 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.

[0815] 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.

[0816] Specific examples of repeating units 7A to 7E are shown below, but are not limited to these. Note that in the following formula, R B This is the same as described above. [ka]

[0817] [ka]

[0818] [ka]

[0819] [ka]

[0820] [ka]

[0821] [ka]

[0822] The polymer-type surfactant may further contain other repeating units besides repeating units 7A to 7E. Specific examples of other repeating units include repeating units obtained from methacrylic acid or α-trifluoromethylacrylic acid derivatives. The content of repeating units 7A to 7E in the polymer-type surfactant is preferably 20 mol% or more, more preferably 60 mol% or more, and even more preferably 100 mol% of the total repeating units.

[0823] 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.

[0824] One method for synthesizing the polymer-type surfactant is to polymerize a monomer containing an unsaturated bond that provides at least one repeating unit selected from 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.

[0825] 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.

[0826] 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.

[0827] [(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.

[0828] [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.

[0829] 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.

[0830] 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.

[0831] 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.

[0832] 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.

[0833] 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.

[0834] 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.

[0835] 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.

[0836] 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.

[0837] 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.

[0838] 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.

[0839] 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]

[0840] 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.

[0841] [1] Synthesis of sulfonium salts [Example 1-1] Synthesis of sulfonium salt PAG-1 [ka]

[0842] (1) Synthesis of PAG-1 Under a nitrogen atmosphere, compound SM-1 (8.6g), compound SM-2 (5.5g), methylene chloride (50g), and water (30g) were added. After stirring for 15 minutes, the organic layer was separated, washed with water, and then concentrated under reduced pressure. Methyl isobutyl ketone (50g) was added to the concentrate and azeotropic dehydration was performed. The residue was further purified by silica gel column chromatography to obtain 11.5g of the target product, PAG-1, as an oily substance (yield 94%).

[0843] MALDI TOF-MS: POSITIVE M + 515(C 26 H 28 F5OS2 + equivalent) NEGATIVE M - 711(C 10 H3F5I3O5S - equivalent)

[0844] [Examples 1-2 to 1-9] Synthesis of sulfonium salts PAG-2 to PAG-9 Using corresponding raw materials and known organic synthesis reactions, sulfonium salts PAG-2 to PAG-9, represented by the following formulas, were synthesized. [ka]

[0845] [ka]

[0846] [ka]

[0847] [2] Synthesis of base polymers [Synthesis Examples 1-5] Synthesis of base polymers (P-1-P-5) Each monomer was combined and copolymerized in MEK, a solvent. The reaction solution was then added to hexane, and the precipitated solid was washed with hexane, isolated, and dried to obtain base 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: THF, standard: polystyrene). [ka]

[0848] [3] Preparation of chemically amplified resist compositions [Examples 2-1 to 2-30, Comparative Examples 1-1 to 1-20] Photoacid generators (PAG-1 to PAG-9) consisting of sulfonium salts of the present invention, comparative photoacid generators (PAG-A to PAG-E), other photoacid generators (PAG-X), base polymers (P-1 to P-5), and quenchers (Q-1 to Q-4) 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. Chemical amplification resist compositions (R-1 to R-30 and CR-1 to CR-20) were then prepared by filtering the solutions through a 0.2 μm Teflon® type filter.

[0849] [Table 1]

[0850] [Table 2]

[0851] In Tables 1 and 2, the solvent, other photoacid generators PAG-X, PAG-Y, comparative photoacid generators PAG-A to PAG-E, quenchers Q-1 to Q-4, and surfactant A are as follows. • Solvent: PGMEA (Propylene glycol monomethyl ether acetate) EL (Ethyl Lactate) DAA (Diacetone Alcohol)

[0852] Other photoacid generators: PAG-X [ka]

[0853] • Comparative photoacid generators: PAG-A ~ PAG-E [ka]

[0854] • Quencher: Q-1~Q-4 [ka]

[0855] • 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

[0856] [4] EUV lithography evaluation (1) [Examples 3-1 to 3-30, Comparative Examples 2-1 to 2-20] Each of the chemically amplified resist compositions (R-1 to R-30, CR-1 to CR-20) shown in Tables 1 to 3 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.

[0857] [Sensitivity evaluation] The optimal exposure dose Eop(mJ / cm²) for obtaining an LS pattern with a line width of 18nm and a pitch of 36nm is obtained. 2 The value of ) was calculated and defined as the sensitivity. The smaller this value, the higher the sensitivity.

[0858] [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| / Eop) × 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. Eop: Optimal exposure amount to give an LS pattern with a line width of 18nm and a pitch of 36nm.

[0859] [LWR rating] The LS pattern obtained by irradiating with Eop 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 these results. The smaller this value, the less roughness and the more uniform the line width pattern obtained.

[0860] [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.

[0861] [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.

[0862] [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.

[0863] [Table 3]

[0864] [Table 4]

[0865] The results shown in Tables 3 and 4 indicate that the chemically amplified resist composition containing the sulfonium salt photoacid generator of the present invention exhibits good sensitivity and excellent EL, LWR, and DOF. Furthermore, it was confirmed that the tilt limit value is small, and that the pattern is resistant to tilting even in fine pattern formation. Development defects were also suppressed. Therefore, the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[0866] [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) shown in Tables 1 to 3 was spin-coated onto a Si substrate formed with a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. 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 dimension 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.

[0867] [Table 5]

[0868] [Table 6]

[0869] The results shown in Tables 5 and 6 confirm that the chemically amplified resist composition containing the photoacid generator made of sulfonium salt of the present invention exhibits good sensitivity and excellent CDU.

Claims

1. A sulfonium salt represented by the following formula (1). 【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 are each independently a halogen atom, a nitro group, a cyano 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 1 may be the same as or different from each other, and two R 1 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 2 may be the same as or different from each other, and two R 2 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 3 may be the same as or different from each other, and two R 3 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. R AL1 , R AL2 and R AL3 These are each independently acid-unstable groups. When n3 is 2, each R AL1 These may be the same or different from each other. When n7 is 2, each R AL2 These may be the same or different from each other. When n11 is 2, each R AL3 They may be the same as or different from each other. At least one - SF 5 The base is -O-R AL1 , -O-R AL2 OR OR AL3 It is bonded to a carbon atom adjacent to the carbon atom to which it is 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. Z - (This is a fluoroalkanesulfonic acid anion that does not have polymerizable groups.)

2. The sulfonium salt according to claim 1, which is represented by the following formula (1A). 【Chemistry 2】 (In the formula, n2 to n4, n6 to n8, n10 to n12, R AL1 ~R AL3 , R 1 ~R 3 and Z - (This is the same as above.)

3. The sulfonium salt according to claim 1, wherein the acid-unstable group is a group represented by the following formula (AL-1) or (AL-2). 【Transformation 3】 (In the formula, m1 and m2 are independently either 0 or 1.) R L1 and R L2 These are, independently, hydrocarbyl groups having 1 to 12 carbon atoms. L3 R is a hydrogen atom or a hydrocarbyl group having 1 to 12 carbon atoms. L1 , R L2 and R L3 The hydrocarbyl group represented by -CH 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 - may be replaced with -O- or -S-. However, R L3 If it is a hydrogen atom, R L1 and R L2 These atoms bond to each other, forming an alicyclic ring containing multiple bonds with the carbon atoms to which they bond. 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. A 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 A It is either -O- or -S-. * represents a bond with an adjacent -O-.

4. Z - The sulfonium salt according to claim 1, wherein the anion is represented by any of the following formulas (Z-1) to (Z-3). 【Chemistry 4】 (In the formula, R 11 This is a hydrocarbyl group having 1 to 60 carbon atoms, which may contain a fluorine atom or a heteroatom. R 12 This is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. x is 1, 2, or 3. y is 1, 2, 3, 4, or 5. z is 0, 1, 2, or 3, where 1 ≤ y + z ≤ 5. X BI This is an iodine atom or a bromine atom. L 1 This is a single bond, ether bond, ester bond, sulfonic acid ester bond, carbonate bond, carbamate bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms, and the -CH of the hydrocarbylene group 2 - may be partially substituted with an ether bond or an ester bond. L 2 When x is 1, it is a C1-C20 hydrocarbylene group which may contain a single bond or a heteroatom, and when x is 2 or 3, it is a C1-C20 (x+1) valent hydrocarbon group which may contain a heteroatom. L 3 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, or carbamate bonds. R 13 This includes a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom, a pentafluorosulfanyl group, an amino group, a C1-C20 hydrocarbyl group, a C1-C20 hydrocarbyloxy group, a C1-C20 hydrocarbylthio group, a C2-C20 hydrocarbylcarbonyl group, a C2-C20 hydrocarbyloxycarbonyl group, a C2-C20 hydrocarbylcarbonyloxy group, a C1-C20 hydrocarbylsulfonyloxy group, and -N(R 13A )(R 13B ), -N(R 13C )-C(=O)-R 13D or -N(R 13C )-C(=O)-O-R 13D The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylthio group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may contain at least one selected from fluorine, chlorine, bromine, iodine, hydroxyl, amino, ester, and ether bonds. 13A and R 13B Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 13C 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. 13D This group 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 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. Rf 1 ~Rf 4 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 1 and Rf 2 (These may combine to form a carbonyl group.)

5. A photoacid generator comprising a sulfonium salt according to any one of claims 1 to 4.

6. A chemically amplified resist composition comprising the photoacid generator described in claim 5.

7. Furthermore, the chemically amplified resist composition according to claim 6, comprising a base polymer containing a polymer that further includes at least one selected from repeating units represented by the following formula (a1), repeating units represented by the following formula (a2), and repeating units represented by the following formula (a3). 【Transformation 5】 (In the formula, R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 This refers to a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-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, a phenylene group, or a 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. X 2 The bond is either a single bond or *-C(=O)-O-. * represents a bond with a carbon atom in the main chain. R 21 This is a halogen atom, a cyano group, a hydroxyl group, a nitro group, a pentafluorosulfanyl group, a C1-C20 hydrocarbyl group which may contain 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 21 They may be the same as or different from each other. AL 1 and AL 2 These are, independently, acid-unstable groups. a1 is 0, 1, 2, 3, or 4. 【Transformation 6】 (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)-N(H)-. 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 22 and R 23 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hydrogen atom or a hetero atom. Also, R 22 and R 23 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. R 24 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom, a hydroxy group, a cyano group, a nitro group, a pentafluorosulfanyl group, or a hetero atom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a hetero atom or -N(R 24A )(R 24B ). R 24A and R 24B are each independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. When b2 is 2 or more, each R 24 may be the same as or different from each other, and a plurality of R 24 may combine with each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached. )

8. The chemically amplified resist composition according to claim 7, wherein the polymer comprises repeating units represented by the following formula (b1) or (b2). 【Transformation 7】 (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 31 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 32 This is a halogen atom, a carboxyl group, a nitro group, a cyano group, a pentafluorosulfanil group, a C1-C20 hydrocarbyl group which may contain 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 32 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.

9. The chemically amplified resist composition according to claim 7, 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). 【Transformation 8】 (In the formula, d1 and d2 are independently 0, 1, 2, or 3.) 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. 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)-O-Z 21 -, **-C(=O)-N(H)-Z 21 - or **- O - Z 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. Z 3 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, amide 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 consists of a single bond, an optionally substituted phenylene group, an optionally substituted naphthylene group, and *-C(=O)-O-Z. 51 - or * - C(=O) - N(R) - Z 51 - is Z 51 R is a C1-C10 aliphatic hydrocarbylene group, phenylene group, or naphthylene group, and the aliphatic hydrocarbylene group may contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or a lactone ring. R is a C1-C10 hydrocarbyl group which may contain a hydrogen atom or a heteroatom. Z 6 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, amide bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Z 7 Each of these is independently a single bond, ***-Z 71 -C(=O)-O-, ***-C(=O)-N(R)-Z 71 - or *** - O - Z 71 - is. is. Z 71 R is a hydroxylene group having 1 to 20 carbon atoms, which may contain heteroatoms. R is the same as described above. Z 8 These are, independently, single bonds, ****-Z 81 -C(=O)-O-, ****-C(=O)-N(R)-Z 81 - or ****-O-Z 81 - is Z 81 R is a hydroxylene group having 1 to 20 carbon atoms, which may contain heteroatoms. R is the same as described above. 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(R)-Z 91 - or * - O - Z 91 - is Z 91 R 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. R is the same as described above. * 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 11 These are single bonds, ether bonds, ester bonds, carbonyl groups, sulfonic acid ester bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Rf 11 and Rf 12 Each of these is independently either a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 13 and Rf 14 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 15 and Rf 16 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 15 and Rf 16 They cannot simultaneously become hydrogen atoms. Rf 17 is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, a fluorinated alkylthio group having 1 to 6 carbon atoms, or a pentafluorosulfanil group. When e2 is 2, 3, or 4, each Rf 17 They may be the same as or different from each other. R 41 and R 42 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. Also, R 41 and R 42 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. R 43 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 43 They may be the same or different from each other, and there may be multiple R 43 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.

10. Furthermore, the chemically amplified resist composition according to claim 6, further comprising an organic solvent.

11. Furthermore, the chemically amplified resist composition according to claim 6, further comprising a quencher.

12. Furthermore, the chemically amplified resist composition according to claim 6, comprising a photoacid generator other than the photoacid generator described in claim 5.

13. Furthermore, the chemically amplified resist composition according to claim 6, further comprising a surfactant.

14. A pattern forming method comprising the steps of: forming a resist film on a substrate using the chemically amplified resist composition according to claim 6; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer.

15. The pattern formation method according to claim 14, wherein the high-energy beam is a KrF excimer laser beam, an ArF excimer laser beam, an electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

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