Sulfonium salt type monomer, polymer, chemically amplified resist composition, and patterning method

Abstract

The present invention provides a sulfonium salt type monomer used in a chemically amplified resist composition for photolithography using high-energy rays, which exhibits excellent solvent solubility, high sensitivity, high contrast, excellent lithography performance such as LWR, CDU, EL, and DOF, and is also resistant to pattern deformation and etching even in the formation of fine patterns; a polymer containing repeating units derived from the sulfonium salt type monomer; a chemically amplified resist composition containing the polymer; and a method for forming patterns using the chemically amplified resist composition. [Solution] A sulfonium salt type monomer represented by the following formula (a). TIFF2026126675000858.tif46121 (Z - It is a carboxylic acid anion having an aromatic vinyl structure and an iodine atom.

Description

[Technical Field]

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

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern rules is progressing rapidly. In particular, the expansion of the flash memory market and the increase in storage capacity are driving this miniaturization. As for the most advanced miniaturization technology, mass production of 65nm node devices using ArF lithography is underway, and preparations for mass production of next-generation 45nm node devices using ArF immersion lithography are underway. For next-generation 32nm node devices, immersion lithography using ultra-high NA lenses combining a liquid with a higher refractive index than water, a high refractive index lens, and a high refractive index resist film, extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm, and double exposure (double patterning lithography) of ArF lithography are among the candidates and are currently being investigated.

[0003] As miniaturization progresses and approaches the diffraction limit of light, the contrast of light decreases. This decrease in light contrast leads to a reduction in the resolution of hole patterns and trench patterns, as well as a decrease in the focus margin, in positive resist films.

[0004] As patterns become finer, the line width roughness (LWR) of line patterns and the dimensional uniformity (CDU) of hole patterns are becoming problematic. The effects of uneven distribution and aggregation of base polymers and acid generators, as well as the effects of acid diffusion, have been pointed out. Furthermore, LWR tends to increase as the resist film thins, and the degradation of LWR due to thinning as finer patterns progress is becoming a serious problem.

[0005] In resist compositions for EUV lithography, it is necessary to simultaneously achieve high sensitivity, high resolution, and low LWR. Shortening the acid diffusion distance reduces LWR but also lowers sensitivity. For example, lowering the post-exposure bake (PEB) temperature reduces LWR but lowers sensitivity. Increasing the amount of quencher added also reduces LWR but lowers sensitivity. It is necessary to overcome the trade-off relationship between sensitivity and LWR.

[0006] To suppress acid diffusion, resist compounds containing repeating units derived from onium salts of polymerizable unsaturated sulfonic acids have been proposed (Patent Document 1). Such so-called polymer-bound acid generators have the characteristic of very short acid diffusion because polymer-type sulfonic acids are generated upon exposure. Furthermore, sensitivity can be improved by increasing the ratio of the acid generator. In the case of additive-type acid generators, increasing the amount added also increases sensitivity, but in this case the acid diffusion distance also increases. Since acids diffuse non-uniformly, increased acid diffusion degrades LWR and CDU. Polymer-type acid generators can be said to have high capability in balancing sensitivity, LWR, and CDU.

[0007] 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 2 describes a photoacid generator in which iodine atoms are introduced into an anion, and patent document 3 describes a photoacid generator containing a polymerizable group in which iodine atoms are introduced into an 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.

[0008] To further suppress acid diffusion, resist compositions have been proposed that use a polymer bound type quencher containing repeating units derived from a sulfonium salt of a weak acid with a pKa of -0.8 or higher that has polymerizable groups (Patent Documents 4-8). In Patent Document 4, examples of weak acids include carboxylic acids, sulfonamides, phenols, and hexafluoroalcohols. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 4425776 [Patent Document 2] Patent No. 6720926 [Patent Document 3] Patent No. 6973274 [Patent Document 4] International Publication No. 2019 / 167737 [Patent Document 5] International Publication No. 2022 / 264845 [Patent Document 6] Japanese Patent Publication No. 2022-115072 [Patent Document 7] Patent No. 7433394 [Patent Document 8] Japanese Patent Publication No. 2024-178693 [Overview of the project] [Problems that the invention aims to solve]

[0010] In acid-catalyzed chemically amplified resist compositions, there is a need for the development of resist compositions that offer even higher sensitivity, improve lithography performance such as LWR, CDU, exposure margin (EL), and depth of field (DOF), and exhibit excellent etching resistance after pattern formation.

[0011] The present invention has been made in view of the above circumstances, and aims to provide a sulfonium salt type monomer used in a chemically amplified resist composition that is excellent in solvent solubility, high sensitivity and high contrast, excellent in lithography performance such as LWR, CDU, EL, DOF, and is resistant to pattern deformation and etching resistance even in fine pattern formation, a polymer containing repeating units derived from the sulfonium salt type monomer, a chemically amplified resist composition containing the polymer, and a method for forming a pattern using the chemically amplified resist composition. [Means for solving the problem]

[0012] As a result of diligent research to achieve the above objective, the inventors have discovered that by using a polymer containing repeating units derived from a sulfonium salt, which includes a carboxylate anion having a styrene or vinylnaphthalene structure as a polymerizable group and an iodine atom, 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, a chemically amplified resist composition can be obtained that exhibits excellent solvent solubility, high sensitivity, improved lithography performance such as LWR, CDU, EL, and DOF, high contrast and high resolution, and excellent etching resistance, thereby completing the present invention.

[0013] In other words, the present invention provides the following sulfonium salt type monomers, polymers, chemically amplified resist compositions, and pattern formation methods. 1. A sulfonium salt type monomer represented by the following formula (a). [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, 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, 0 ≤ n10 + n11 + n12 ≤ 5, and when n9 is 1, 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 combine with each other to form a ring together with the carbon atom to which they are attached. When n8 is 2, each R 2 may be the same as or different from each other, and two R 2 may combine with each other to form a ring together with the carbon atom to which they are attached. When n12 is 2, each R 3 may be the same as or different from each other, and two R 3 may combine with each other to form a ring together with the carbon atom to which they are attached.) R AL1 , R AL2 and R AL3 are each independently an acid-labile group. When n3 is 2, each R AL1 may be the same as or different from each other. When n7 is 2, each R AL2These 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 -SF5 unit is -OR AL1 , -OR AL2 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 - It is a carboxylic acid anion having an aromatic vinyl structure and an iodine atom. 2. A sulfonium salt type monomer of 1, represented by the following formula (a1). [ka] (In the formula, n2~n4, n6~n8, n10~n12, R AL1 ~R AL3 , R 1 ~R 3 and Z - (This is the same as above.) 3. The sulfonium salt of 1 or 2 wherein the acid-unstable group is a group represented by the following formula (AL-1) or (AL-2). [ka] (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 L3A 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. 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. R L4 and R L5 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. L6 is a hydrocarbyl group having 1 to 20 carbon atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with -O- or -S-. Also, R L5 and R L6 However, they bond to each other, and the carbon atoms and L that they bond to are bonded together. 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-. L A It is either -O- or -S-. * represents a bond with an adjacent -O-. 4.Z - However, it is one of the sulfonium salt type monomers 1 to 3, which are anions represented by the following formula (Z). [ka] (In the formula, m1 is 0 or 1. m2 is 0, 1, 2, 3 or 4. m3 is 0, 1, 2 or 3. m4 is 0 or 1. m5 is 0, 1, 2, 3 or 4. m6 is 0, 1, 2 or 3. m7 is 0 or 1. m8 is 1, 2, 3 or 4. m9 is 0, 1, 2 or 3. m10 is 0 or 1. m11 is 0 or The answer is 1. However, when m1 is 0, 0 ≤ m2 + m3 + m11 ≤ 4, and when m1 is 1, 0 ≤ m2 + m3 + m11 ≤ 6. When m4 is 0, 0 ≤ m5 + m6 ≤ 4, and when m4 is 1, 0 ≤ m5 + m6 ≤ 6. When m7 is 0, 0 ≤ m8 + m9 ≤ 5, and when m7 is 1, 0 ≤ m8 + m9 ≤ 7. Also, 1 ≤ m2 + m5 + m8 ≤ 4. R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 4 , R 5 and R 6 Each of these is independently a halogen atom other than an iodine atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl 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 C1-C20 hydrocarbylthio group which may contain a heteroatom, or a C1-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. When m3 is 2 or 3, each R 4 The two Rs may be identical or different from each other. 4 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When m6 is 2 or 3, each R 5 The two Rs may be identical or different from each other. 5 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When m9 is 2 or 3, each R 6 The two Rs may be identical or different from each other. 6 These atoms may bond with each other to form a ring with the carbon atoms to which they are bonded. L A1 , L A2 , L B1 and LB2 These are, independently, a single bond, an ether bond, a carbonyl group, an ester bond, a sulfonic acid ester bond, an amide bond, a sulfonic acid amide bond, a carbonate bond, or a carbamate bond. X L1 and X L2 Each of these is a hydroxylene group having 1 to 40 carbon atoms, which may contain single bonds or heteroatoms. A sulfonium salt type quencher consisting of one of the sulfonium salt type monomers from 5.1 to 4. A polymer containing repeating units derived from a 6.5 sulfonium salt type quencher. 7. Six polymers further comprising at least one selected from the repeating units represented by the following formula (b1), the following formula (b2), and the following formula (b3). [ka] (In the formula, R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 This consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-OX. 11 -or *-C(=O)-N(H)-X 11 -The phenylene group or naphthylene group may be substituted with a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. 11 This is a saturated hydrocarbylene group, 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 These are single bonds, *-C(=O)-O-, or *-C(=O)-N(H)-. * represents a bond with a carbon atom in the main chain. R 11This 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. When a1 is 2, 3, or 4, each R 11 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. [ka] (In the formula, b1 is either 0 or 1. When b1 is 0, b2 is 0, 1, 2, or 3, and when b1 is 1, b2 is 0, 1, 2, 3, 4, or 5.) R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 3 The bonds are single bonds, *-C(=O)-O-, or *-C(=O)-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 12 and R 13 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom. 12 and R 13may combine with each other to form a ring together with the carbon atoms to which they are attached. R 14 is a halogen atom, a hydroxy group, a cyano group, a nitro group, a pentafluorosulfanyl 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, 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 14A )(R 14B ). R 14A and R 14B are each independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms When b2 is 2 or more, each R 14 may be the same as or different from each other, and a plurality of R 14 may combine with each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached.) 8. Further, a polymer of 6 or 7 containing a repeating unit represented by the following formula (c).

Chemical formula

[29] ]]11. (A) A chemically amplified resist composition containing a base polymer containing a polymer of any one of 6 to 10. 12. Further, (B) the chemically amplified resist composition of 11, containing an organic solvent. 13. A further chemically amplified resist composition 11 or 12 comprising (C) a quencher. 14. Furthermore, (D) any of the chemically amplified resist compositions of 11 to 13 comprising an acid generator. 15. Furthermore, (E) any of the chemically amplified resist compositions of 11 to 14 comprising a surfactant. A pattern forming method comprising the steps of: forming a resist film on a substrate using any of the chemically amplified resist compositions described in 16.11 to 15; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer. 17. Pattern formation method 16 wherein the high-energy beam is ArF excimer laser light with a wavelength of 193 nm or KrF excimer laser light with a wavelength of 248 nm, an electron beam or extreme ultraviolet light with a wavelength of 3 to 15 nm. [Effects of the Invention]

[0014] A resist film containing a polymer with repeating units derived from a sulfonium salt monomer represented by formula (a) exhibits good solvent solubility and, due to the large atomic weight of iodine atoms, has low acid diffusion. This prevents a decrease in resolution due to blurring caused by acid diffusion, improving lithography performance such as LWR, CDU, EL, and DOF. Furthermore, because the absorption by iodine atoms at a wavelength of 13.5 nm is very large, secondary electrons are generated from iodine atoms during exposure, resulting in increased sensitivity. In addition, the pentafluorosulfanil group contained in the cation is a strong electron-withdrawing group, and its attachment to the aromatic ring of the sulfonium cation lowers the LUMO in frontier molecular kinetic theory, making it easier to accept secondary electrons and thus promoting the decomposition of the sulfonium cation. Moreover, acid-unstable groups having a tertiary / secondary ether structure, tertiary / secondary carbonate structure, or acetal structure attached to the aromatic ring of the sulfonium cation undergo 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 exposed and unexposed areas. Furthermore, the bonding of a pentafluorosulfanil group to a carbon atom adjacent to the carbon atom to which the generated phenolic hydroxyl group is bonded increases the acidity of the phenols due to the electron-withdrawing properties of the pentafluorosulfanil group. When developing the exposed area, where the deprotection reaction has progressed, with an alkaline developer, the increased acidity of the phenols improves solubility in the alkaline developer, suppressing development residue and preventing swelling caused by the alkaline developer, thereby preventing the deformation of the resist pattern. On the other hand, the carboxylic acid anion is relatively basic and can effectively trap acids generated from strong acids. This makes it possible to construct a chemically amplified resist composition that is highly sensitive while exhibiting improved lithography performance such as LWR, CDU, EL, and DOF. Additionally, the aromatic ring acts as a good etching-resistant group, making it suitable for fine pattern formation. [Modes for carrying out the invention]

[0015] [Sulfonium salt type monomer] The sulfonium salt type monomer of the present invention is represented by the following formula (a). [ka]

[0016] In formula (a), 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.

[0017] In formula (a), 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 0 and it is a benzene ring. 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.

[0018] In formula (a), 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.

[0019] In equation (a), 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.

[0020] In formula (a), 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.

[0021] 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.

[0022] In formula (a), 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.

[0023] The acid-unstable group is preferably one represented by the following formula (AL-1) or (AL-2). [ka] (In the formula, * represents a bond.)

[0024] In equations (AL-1) and (AL-2), m1 and m2 are independently either 0 or 1.

[0025] 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.

[0026] 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.

[0027] In formula (AL-2), L A It is either -O- or -S-.

[0028] 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]

[0029] [ka]

[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

Chem.

[0042]

Chem.

[0043]

Chem.

[0044]

Chem.

[0045]

Chem.

[0046]

Chem.

[0047]

Chem.

[0048]

Chem.

[0049] [

Chem.

[0050] Specific examples of the acid-labile group represented by formula (AL-2) include, but are not limited to, those shown below. In the following formulas, * represents a bond to the adjacent -O-. [Chemical]

[0051] [Chemical]

[0052] In formula (a), 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. By the -SF5 group and -O-R AL1 , -O-R AL2 or -O-R AL3 being bonded to adjacent carbon atoms to each other, the acidity of the phenols after -R AL1 , -R AL2 or -R AL3 is deprotected is improved, and the dissolution contrast is improved.

[0053] 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. At this time, specific examples of the structure of the ring include those represented by the following formula and the like. [Chemical] (In the formula, the dashed line is a bond.)

[0054] As the sulfonium salt represented by formula (a), those represented by the following formula (a1) are preferable. [Chemical] (In the formula, n2~n4, n6~n8, n10~n12, R AL1 ~R AL3 and R 1 ~R 3 are the same as those described above. Z - will be described later.)

[0055] Specific examples of cations of sulfonium salts represented by formula (a) are listed below, but are not limited to these. In the following formula, Me represents a methyl group. [ka]

[0056] [ka]

[0057] [ka]

[0058] [ka]

[0059] [ka]

[0060] [ka]

[0061] [ka]

[0062] [ka]

[0063] [ka]

[0064] [ka]

[0065]

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[0066]

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[0067]

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[0068]

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[0069]

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[0070]

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[0071]

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[0072]

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[0073]

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[0074]

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[0416] [ka]

[0417] [ka]

[0418] In equations (a) and (a1), Z - This is a carboxylic acid anion having an aromatic vinyl structure and an iodine atom. The carboxylic acid anion is preferably represented by the following formula (Z). [ka]

[0419] In formula (Z), m1 is 0 or 1. When m1 is 0, it is a benzene ring, and when m1 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, a benzene ring with m1 being 0 is preferred. m2 is 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, m2 is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2, and even more preferably 0 or 1. m3 is 0, 1, 2, or 3.

[0420] In formula (Z), m4 is either 0 or 1. When m4 is 0, it is a benzene ring, and when m4 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, a benzene ring with m4 being 0 is preferred. m5 is either 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, m5 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. m6 is either 0, 1, 2, or 3.

[0421] In formula (Z), m7 is either 0 or 1. When m7 is 0, it is a benzene ring, and when m7 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, a benzene ring with m7 being 0 is preferred. m8 is either 1, 2, 3, or 4. From the viewpoint of raw material procurement, m8 is preferably 1, 2, or 3, and more preferably 1 or 2. m9 is either 0, 1, 2, or 3.

[0422] In equation (Z), m10 is either 0 or 1. m11 is either 0 or 1.

[0423] However, when m1 is 0, 0 ≤ m2 + m3 + m11 ≤ 4, and when m1 is 1, 0 ≤ m2 + m3 + m11 ≤ 6. When m4 is 0, 0 ≤ m5 + m6 ≤ 4, and when m4 is 1, 0 ≤ m5 + m6 ≤ 6. When m7 is 0, 0 ≤ m8 + m9 ≤ 5, and when m7 is 1, 0 ≤ m8 + m9 ≤ 7. Furthermore, regarding the number of iodine atoms in the anion, the absorption increases, especially for EUV, as the number of iodine atoms increases, but there is a concern that the solvent solubility will decrease and precipitate in the resist composition, so it is preferable that 1 ≤ m2 + m5 + m8 ≤ 4.

[0424] In formula (Z), R A This is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Of these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0425] In formula (Z), R 4This includes halogen atoms other than iodine, nitro groups, cyano groups, hydroxyl groups, carboxyl groups, pentafluorosulfanyl groups, C1-C20 hydrocarbyl groups which may contain heteroatoms, C1-C20 hydrocarbyloxy groups which may contain heteroatoms, C1-C20 hydrocarbylthio groups which may contain heteroatoms, or C1-C20 hydrocarbyloxycarbonyl groups which may contain heteroatoms. The halogen atom other than iodine is preferably a fluorine atom, a chlorine atom, or a bromine atom, and more preferably a fluorine atom. The hydrocarbyl portion of the hydrocarbyl group, hydrocarbyloxy group, and 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 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- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When m3 is 2 or 3, each R. 4 They may be the same as or different from each other.

[0426] Also, when m3 is 2 or 3, the two R 4 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.

[0427] In formula (Z), R 5This is a halogen atom other than iodine, a nitro group, a cyano group, a hydroxyl group, a carboxyl 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 C1-C20 hydrocarbylthio group which may contain a heteroatom, or a C1-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. Specific examples of the halogen atom other than iodine include fluorine, chlorine, and bromine. The hydrocarbyl portion of the hydrocarbyl group, hydrocarbyloxy group, and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 4 Examples of hydrocarbyl groups represented by the above are similar to those exemplified, but are not limited to 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- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When m6 is 2 or 3, each R 5 They may be the same as or different from each other.

[0428] Also, when m6 is 2, the two R 5 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.

[0429] In formula (Z), R 6This is a halogen atom other than iodine, a nitro group, a cyano group, a hydroxyl group, a carboxyl 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 C1-C20 hydrocarbylthio group which may contain a heteroatom, or a C1-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. Specific examples of the halogen atom other than iodine include fluorine, chlorine, and bromine. The hydrocarbyl portion of the hydrocarbyl group, hydrocarbyloxy group, and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 4 Examples of hydrocarbyl groups represented by the above are similar to those exemplified, but are not limited to 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- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When m9 is 2 or 3, each R 6 They may be the same as or different from each other.

[0430] Also, when m9 is 2, the two R 6 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. A 5- to 8-membered ring is preferred.

[0431] In formula (Z), L A1 , L A2 , L B1 and L B2These are, independently, a single bond, an ether bond, a carbonyl group, 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 A1 The bond is preferably a single bond, an ether bond, an ester bond, or a sulfonic acid ester bond, and more preferably an ether bond, an ester bond, or a sulfonic acid ester bond. A2 The bond is preferably a single bond, ether bond, ester bond, amide bond, sulfonic acid amide bond, or sulfonic acid ester bond, and more preferably an ester bond or sulfonic acid ester bond. B1 The bond is preferably a single bond, an ether bond, an ester bond, an amide bond, or a sulfonic acid ester bond, and more preferably a single bond, an ether bond, or an ester bond. B2 Preferably, the bond is a single bond, ether bond, ester bond, amide bond, or sulfonic acid ester bond, and more preferably a single bond, ether bond, or ester bond.

[0432] If m11 is 1, L A1 and L A2 Preferably, the substituent is bonded to a carbon atom adjacent to the aromatic ring. In this case, since the substituent containing the fluorosulfonic acid anion structure and the substituent containing the aromatic ring substituted with an iodine atom are located in more spatially close positions, higher sensitivity is expected.

[0433] In formula (Z), X L1 and X L2 Each of these 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.

[0434] X L1 and XL2 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 A1 and L B1 , or L A2 and L B2 This is a combination of the two. [ka]

[0435] [ka]

[0436] [ka]

[0437] [ka]

[0438] Of these, X L -0~X L -22, X L -29~X L -34 and X L -47~X L -61 is preferred.

[0439] Specific examples of anions of onium salt monomers represented by formula (a) are listed 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 across the aromatic ring. [ka]

[0440] [ka]

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[0546] Other specific examples of anions of onium salt type monomers represented by formula (a) include, but are not limited to, those described in

[0049] ,

[0054] -

[0056] ,

[0062] -

[0064] of Japanese Patent Publication No. 7433394 and

[0116] of Japanese Patent Application Publication No. 2024-178693.

[0547] Specific examples of the sulfonium salt type monomer of the present invention include any combination of the anion and cation described above.

[0548] The sulfonium salt monomers of the present invention can be synthesized by known methods. Specifically, the methods described in paragraphs

[0402] to

[0405] of Japanese Patent No. 7433394 are examples, but the synthesis methods are not limited thereto.

[0549] [polymer] The polymer of the present invention contains a repeating unit (hereinafter also referred to as repeating unit a) derived from a sulfonium salt type monomer represented by formula (a).

[0550] The polymer of the present invention is a polymer-bonded quencher that functions as both a quencher and a base polymer in a chemically amplified resist composition. A structural feature of the polymer of the present invention is that it contains repeating units having a salt structure derived from the sulfonium salt monomer of the present invention, which includes a benzene or naphthalene structure directly bonded to the main chain and containing an iodine atom, and a sulfonium cation having a pentafluorosulfanyl group and a hydrocarbyloxycarbonyl group. Since the iodine atom has extremely high absorption of EUV at a wavelength of 13.5 nm, secondary electrons are generated during exposure, and the energy of these secondary electrons is transferred to the acid generator, promoting decomposition and thereby increasing sensitivity. Polymerizable groups consisting of styrene or vinylnaphthalene structures are more rigid than polymerizable groups such as methacrylic acid esters, improving the glass transition temperature (Tg) of the polymer. It is thought that the interaction of aromatic rings within or between polymers (π-π stacking effect) causes the polymer to arrange itself regularly, resulting in resistance to pattern collapse in the developer even during fine pattern formation. Furthermore, even in the etching process after fine pattern formation, the presence of an aromatic ring directly attached to the main chain results in excellent etching resistance. In addition, the pentafluorosulfanil group is a strong electron-withdrawing group, and by substituting it on the aromatic ring of the triarylsulfonium cation, it lowers the LUMO in frontier molecular kinetic theory, making it easier to accept secondary electrons and thus promoting the decomposition of the sulfonium cation. Acid-unstable groups having a tertiary / secondary ether structure, a tertiary / secondary carbonate structure, or an acetal structure substituted on the aromatic ring of the sulfonium cation undergo a deprotection reaction by 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. Moreover, when the pentafluorosulfanil group is bonded to a carbon atom adjacent to the carbon atom to which the generated phenolic hydroxyl group is bonded, the acidity of the phenols is increased due to the electron-withdrawing properties of the pentafluorosulfanil group.When developing the exposed area after the deprotection reaction has progressed with an alkaline developer, the increased acidity of phenols improves their solubility in the alkaline developer, thereby suppressing development residue and preventing the deformation of the resist pattern by suppressing swelling caused by the alkaline developer. On the other hand, carboxylic acid anions are relatively basic and can effectively trap acids generated from strong acids. Due to the synergistic effect of these factors, it is possible to form patterns that are highly sensitive, yet have improved lithography performance such as LWR and CDU, and are resistant to pattern deformation, making them particularly suitable as materials for chemically amplified positive resist compositions.

[0551] 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]

[0552] In equations (b1) and (b2), R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0553] In formula (b1), X 1 This consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-OX. 11 -or *-C(=O)-N(H)-X 11 -The phenylene group or naphthylene group may be substituted with a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. 11 This is a saturated hydrocarbylene group, phenylene group, or naphthylene group having 1 to 10 carbon atoms, and the saturated hydrocarbylene group may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. * represents a bond with a carbon atom of the main chain.

[0554] In formula (b2), X 2 The bond is a single bond, *-C(=O)-O-, or *-C(=O)-N(H)-. * represents a bond with a carbon atom in the main chain. 11 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 11 They may be the same as or different from each other.

[0555] In formulas (b1) and (b2), AL 1 and AL 2 Each of these is 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.

[0556] 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.)

[0557] In equations (AL-3) and (AL-4), R L11 and R L12 Each of these is independently a hydrocarbyl group having 1 to 40 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, or iodine 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.

[0558] In formula (AL-3), a2 is an integer between 0 and 10, preferably 1, 2, 3, 4, or 5.

[0559] 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, fluorine, or iodine 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.

[0560] 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, fluorine, and iodine 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.

[0561] 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.

[0562] Specific examples of repeating unit b1 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]

[0563] [ka]

[0564] [ka]

[0565] [ka]

[0566] [ka]

[0567] [ka]

[0568] [ka]

[0569] Specific examples of repeating unit b2 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]

[0570] [ka]

[0571] [ka]

[0572] The polymer may contain repeating units represented by the following formula (b3) (hereinafter also referred to as repeating unit b3). [ka]

[0573] In formula (b3), 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, a benzene ring with b1 being 0 is preferred. 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, b2 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0574] In equation (b3), 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.

[0575] In equation (b3), 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.

[0576] In equation (b3), X 4These 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.

[0577] In equation (b3), 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. 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.

[0578] In equation (b3), R 12 and R 13Each of these is a C1-C20 hydrocarbyl group which may independently contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, and 4-methylcyclo Examples include cyclic saturated hydrocarbyl groups with 3 to 20 carbon atoms, such as hexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl groups; cyclic unsaturated hydrocarbyl groups with 3 to 20 carbon atoms, such as cyclohexenyl groups; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl groups; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, the material may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0579] Also, R 12 and R 13These may bond with each other to form a ring with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, and so on. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, the ring may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and so on.

[0580] In equation (b3), R 14 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 14A )(R 14B ) is R 14A and R 14B Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and more preferably a fluorine atom or an iodine atom. The hydrocarbyl portion of the hydrocarbyl group and the hydrocarbyloxy group, hydrocarbyloxycarbonyl group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 12 and R 13Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, and nitrogen atoms, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When b2 is 2 or more, each R 14 They may be the same as or different from each other.

[0581] Also, when b2 is 2 or more, multiple R 14 However, they may bond with each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornane rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., and as a result, the ring may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0582] Specific examples of repeating unit b3 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]

[0583]

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[0584]

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[0585]

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[0586]

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[0587]

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[0588]

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[0589]

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[0590]

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[0591]

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[0592]

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[0593]

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[0594]

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[0595]

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[0596]

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[0597]

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[0598]

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[0599]

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[0600]

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[0601]

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[0602]

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[0603]

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[0604]

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[0605]

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[0606]

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[0607]

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[0608]

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[0609]

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[0610]

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[0611]

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[0612]

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[0613]

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[0614]

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[0615]

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[0616]

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[0617]

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[0618]

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[0619]

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[0620]

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[0621]

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[0622]

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[0623]

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[0624]

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[0625] [ka]

[0626] [ka]

[0627] [ka]

[0628] [ka]

[0629] [ka]

[0630] [ka]

[0631] [ka]

[0632] Preferably, the polymer further contains a repeating unit represented by the following formula (c) (hereinafter also referred to as repeating unit c). [ka]

[0633] In formula (c), R A This is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 The bond is a single bond, *-C(=O)-O-, or *-C(=O)-N(H)-. * represents a bond with a carbon atom in the main chain. 21c1 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. c1 is 1, 2, 3, or 4. c2 is 0, 1, 2, or 3. However, 1 ≤ c1 + c2 ≤ 5.

[0634] Specific examples of repeating units c 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]

[0635] [ka]

[0636] [ka]

[0637] [ka]

[0638] [ka]

[0639] Preferably, the polymer further contains repeating units (hereinafter also referred to as repeating unit d) derived from an onium salt type monomer containing a polymerizable group and a fluorosulfonic acid anion and a sulfonium cation having at least one iodine atom.

[0640] Specific examples of anions of repeating unit d include the structures described in

[0023] to

[0029] of Japanese Patent Publication No. 6973274,

[0032] to

[0038] of Japanese Unexamined Patent Publication No. 2023-172928, and

[0032] to

[0047] of Japanese Unexamined Patent Publication No. 2024-043941.

[0641] Furthermore, a specific example of an anion with repeating unit d is also preferable, as it can be represented by the following formula (d1). [ka]

[0642] In formula (d1), d1 is either 0 or 1. When d1 is 0, it is a benzene ring, and when d1 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that d1 is 0 and it is a benzene ring. d2 is either 0 or 1. When d2 is 0, it is a benzene ring, and when d2 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that d2 is 0 and it is a benzene ring. d3 is either 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, d3 is preferably 0, 1, or 2, and more preferably 0 or 1. d4 is either 0, 1, 2, 3, or 4, but is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2, and even more preferably 0 or 1. d5 is either 1, 2, 3, 4, 5, or 6. The more iodine atoms in the anionic structure there are, the higher the absorption, especially to EUV. However, this also leads to poor solvent solubility and concerns about precipitation in the resist composition. Therefore, d5 is preferably 1, 2, or 3, and more preferably 1 or 2. However, when d2 is 0, 1 ≤ d4 + d5 ≤ 4, and when d2 is 1, 1 ≤ d4 + d5 ≤ 6. d6 is 0, 1, 2, 3, or 4, but is preferably 0, 1, 2, or 3, and more preferably 1.

[0643] In formula (d1), R AThis is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Of these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0644] In formula (d1), the iodine atom in the aromatic ring of the anion is L B It is preferable that the iodine atom is bonded to the ortho position of the carbon atom to which it is bonded. Since the iodine atom is an element with a large atomic radius, the rotation of the bond axis between the aromatic ring to which the polymerizable group is bonded and the aromatic ring to which the iodine atom is bonded is suppressed, improving the rigidity of the polymer.

[0645] In formula (d1), R 31This is a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom. 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 group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and eicosyl group; cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-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- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When d3 is 2, 3, or 4, each R 31 They may be the same as or different from each other.

[0646] Also, when d3 is 2, 3, or 4, multiple R 31 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.

[0647] In formula (d1), R 32 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than iodine or heteroatoms. Specific examples of halogen atoms other than iodine include fluorine, chlorine, and bromine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 31 Examples of hydrocarbyl groups represented by the above are similar to those exemplified, but are not limited to these. When d4 is 2, 3, or 4, each R 32 They may be the same as or different from each other.

[0648] Also, when d4 is 2, 3, or 4, multiple R 32 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.

[0649] In formula (d1), L C , L D and L EThese are, independently, a single bond, an ether bond, an ester bond, a sulfonic acid ester bond, a sulfonic acid amide bond, a carbonate bond, or a carbamate bond. Of these, L C 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. D The bond is preferably a single bond, an ether bond, or an ester bond, and more preferably a single bond. E Preferably, the bond is a single bond, an ether bond, an ester bond, or a sulfonic acid ester bond, and more preferably an ether bond or an ester bond.

[0650] In formula (d1), X L3 This is a C1-C40 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. L3 A specific example of a C1-C40 hydrocarbylene group that may contain a heteroatom represented by the formula (Z) is X in the explanation of formula (Z). L1 and X L2 X is an example of a specific example of a C1-C40 hydrocarbylene group that may contain a heteroatom represented by the symbol X. L -0~X L -61 is one example. Of these, X L -0~X L -22, X L -29~X L -34 and X L -47~X L -61 is preferred.

[0651] In terms of the rigidity of the resulting polymer, X L3 It is preferable that the bond is a single bond.

[0652] In formula (d1), Q 1 and Q2 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. A trifluoromethyl group is preferred as the fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms.

[0653] In formula (d1), Q 3 and Q 4 Each of these is independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. A trifluoromethyl group is preferred as the fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Q 3 and Q 4 It is even more preferable that the atom be a fluorine atom.

[0654] In formula (d1), -[C(Q 1 )(Q 2 )] d6 -C(Q 3 )(Q 4 )-SO3 - The following are preferred examples of substructures represented by , but are not limited to these. In the following formula, * represents L C This represents a combination of two things. [ka]

[0655] Of these, Acid-1 to Acid-7 are preferred, and Acid-1 to Acid-3, Acid-6, and Acid-7 are more preferred.

[0656] The anion represented by formula (d1) is preferably the one represented by the following formula (d1-1). [ka] (In the formula, d1~d6, R A , R 31 , R 32 , L C , L E Q 1 ~Q 4 and Z + (This is the same as above.)

[0657] The anion represented by formula (d1-1) is preferably the one represented by formula (d1-2) below. [ka] (In the formula, d1~d6, R A , R 31 , R 32 , L C Q 1 Q 2 and Z + (This is the same as above.)

[0658] Specific examples of anions represented by formula (d1) are listed below, but are not limited to these. Note that in the following formula, R A and Q 1 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]

[0659] [ka]

[0660] [ka]

[0661] [ka]

[0662] [ka]

[0663] [ka]

[0664]

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[0665]

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[0666]

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[0667]

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[0668]

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[0669]

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[0670]

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[0671]

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[0672]

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[0673]

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[0674]

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[0675]

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[0676]

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[0677]

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[0678]

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[0679]

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[0680]

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[0681]

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[0682]

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[0683]

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[0684]

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[0685]

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[0686]

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[0687]

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[0688]

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[0689]

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[0690]

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[0691]

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[0692]

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[0693]

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[0694]

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[0695]

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[0696]

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[0697]

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[0698]

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[0699]

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[0700]

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[0701]

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[0702]

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[0703]

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[0704]

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[0705]

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[0706] [ka]

[0707] [ka]

[0708] [ka]

[0709] [ka]

[0710] [ka]

[0711] [ka]

[0712] [ka]

[0713] [ka]

[0714] [ka]

[0715] As the repeating unit d, an anion represented by the following formula (d2) is also preferred. [ka]

[0716] In formula (d2), d11 is either 0 or 1. When d11 is 0, it is a benzene ring, and when d11 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that d11 is 0 and it is a benzene ring. d12 is either 1, 2, 3, or 4. From the viewpoint of raw material procurement, d12 is preferably 1, 2, or 3, more preferably 1 or 2, and even more preferably 1. d13 is either 0, 1, or 2. However, when d11 is 0, 1 ≤ d12 + d13 ≤ 4, and when d11 is 1, 1 ≤ d12 + d13 ≤ 6.

[0717] In formula (d2), d14 is 0 or 1. When d14 is 0, it is a benzene ring, and when d14 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that d14 is 0 and it is a benzene ring. d15 is 1, 2, 3 or 4, but it is preferable that it is 1, 2 or 3. The more iodine atoms in the anion structure there are, the higher the absorption, especially for EUV, but the poorer the solvent solubility becomes and the greater the concern that it may precipitate in the resist composition, so the number of iodine atoms in the anion is preferably 2, 3, 4 or 5, and more preferably 2, 3 or 4. d16 is 0, 1 or 2. However, when d14 is 0, 1 ≤ d15 + d16 ≤ 4, and when d14 is 1, 1 ≤ d15 + d16 ≤ 6.

[0718] In formula (d2), d17 is 0, 1, 2, 3 or 4, but is preferably 0, 1, 2 or 3, more preferably 1, 2 or 3, and even more preferably 1.

[0719] In formula (d2), R A This is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Of these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0720] In formula (d2), R 33This is a C1-C20 hydrocarbyl group which may contain a halogen atom other than iodine, a nitro 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 halogen atom other than iodine is preferably a fluorine atom, a chlorine atom, or a bromine atom, and more preferably a fluorine atom. The hydrocarbyl portion of the hydrocarbyl group, hydrocarbyloxy group, and 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 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- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When d13 is 2, each R. 33 They may be the same as or different from each other.

[0721] Also, when d13 is 2, the two R 33 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.

[0722] In formula (d2), R 34This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than iodine, a nitro group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, or a C1-C20 hydrocarbylthio group which may contain a heteroatom. Specific examples of halogen atoms other than iodine include fluorine, chlorine, and bromine. The hydrocarbyl portion of the hydrocarbyl group, hydrocarbyloxy group, and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 33 Examples of hydrocarbyl groups represented by the same as those exemplified are, but are not limited to, those shown. When d16 is 2, each R 34 They may be the same as or different from each other.

[0723] Also, when d16 is 2, the two R 34 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.

[0724] In formula (d2), L F1 , L F2 , L G1 and L G2 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 F1 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. F2 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. G1 The bond is preferably a single bond, an ether bond, an ester bond, or a sulfonic acid ester bond, and more preferably a single bond, an ether bond, or an ester bond. G2The bonds are preferably single bonds, ether bonds, ester bonds, or sulfonic acid ester bonds, and more preferably single bonds, ether bonds, or ester bonds.

[0725] L F1 and L F2 Preferably, the substituent is bonded to a carbon atom adjacent to the aromatic ring. In this case, since the substituent containing the fluorosulfonic acid anion structure and the substituent containing the aromatic ring substituted with an iodine atom are located in more spatially close positions, higher sensitivity is expected.

[0726] In formula (d2), X L4 and X L5 Each of these 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. L4 and X L A specific example of a C1-C40 hydrocarbylene group that may contain a heteroatom represented by the formula (Z) is X in the explanation of formula (Z). L1 and X L2 X is an example of a specific example of a C1-C40 hydrocarbylene group that may contain a heteroatom represented by the symbol X. L -0~X L -61 is one example. Of these, X L -0~X L -22, X L -29~X L -34 and X L -47~X L -61 is preferred.

[0727] In formula (d2), Q 11 and Q 12 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. A trifluoromethyl group is preferred as the fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms.

[0728] In formula (d2), Q 13 and Q 14 Each of these is independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. A trifluoromethyl group is preferred as the fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Q 13 and Q 14 It is even more preferable that the atom be a fluorine atom.

[0729] In formula (d2), -[C(Q 11 )(Q 12 )] d17 -C(Q 13 )(Q 14 )-SO3 - The following are preferred examples of substructures represented by , but are not limited to these. In the following formula, * represents L G1 This represents a combination of two things. [ka]

[0730] Of these, Acid-1 to Acid-7 are preferred, and Acid-1 to Acid-3, Acid-6, and Acid-7 are more preferred.

[0731] The anion represented by formula (d2) is preferably the one represented by formula (d2-1) below. [ka] (In the formula, R A , R 33 , R 34 , L F1 , L F2 Q 11 ~Q 14 (And d11~d17 are the same as above.)

[0732] The anion represented by formula (d2-1) is preferably the one represented by formula (d2-2) below. [ka] (In the formula, R A , R 33 , R 34 , L F2 Q 11 Q 12 (And d11~d17 are the same as above.)

[0733] Specific examples of anions represented by formula (d2) are listed below, but are not limited to these. Note that in the following formula, R A and Q 11 The same as described above, and Me is a methyl group. Furthermore, the bonding positions of the various substituents on the aromatic ring may be interchanged. [ka]

[0734] [ka]

[0735] [ka]

[0736] [ka]

[0737] [ka]

[0738] [ka]

[0739] [ka]

[0740]

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[0741]

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[0742]

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[0743]

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[0744]

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[0745]

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[0746]

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[0747]

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[0748]

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[0749]

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[0750]

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[0751]

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[0752]

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[0753]

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[0754]

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[0755]

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[0756]

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[0757]

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[0758]

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[0759]

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[0760]

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[0761]

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[0762]

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[0763]

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[0764]

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[0773]

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[0792] Specific examples of sulfonium cations of repeating unit d include, but are not limited to, those exemplified as sulfonium cations of sulfonium salt type monomers represented by formula (a), 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, and those described in paragraphs

[0035] to

[0046] of Japanese Patent No. 7491173.

[0793] Furthermore, as the repeating unit d, a sulfonium cation represented by the following formula (d3) is also preferred. [ka]

[0794] In formula (d3), d21 is either 0 or 1. When d21 is 0, it is a benzene ring, and when d21 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that d21 is 0 and it is a benzene ring. d22 is either 0 or 1. When d22 is 0, it is a benzene ring, and when d22 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that d21 is 0 and it is a benzene ring. d23 is either 0 or 1. When d23 is 0, it is a benzene ring, and when d23 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that d23 is 0 and it is a benzene ring.

[0795] In formula (d3), d24 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, d24 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0796] In formula (d3), d25 is 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, d25 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. d26 is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material procurement, d26 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. d27 is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material procurement, d27 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0797] In formula (d3), d28 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that d28 is 0 or 1. d29 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that d29 is 0 or 1. d30 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that d30 is 0 or 1.

[0798] In formula (d3), d31 is either 0 or 1. When d31 is 0, it is a benzene ring, and when d31 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, a benzene ring with d31 being 0 is preferred.

[0799] In formula (d3), d32 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 increases solvent solubility and raises concerns about precipitation in the resist composition. Therefore, d32 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0800] In formula (d3), d33 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that d33 is 0 or 1. d34 is 0, 1, or 2. From the viewpoint of synthesis, it is preferable that d34 is 0 or 1.

[0801] However, when d21 is 0, 0≦d26+d29≦4, and when d21 is 1, 0≦d26+d29≦6. When d22 is 0, 0≦d27+d30≦4, and when d22 is 1, 0≦d27+d30≦6. When d23 is 0, 1≦d24+d25+d28+d34≦4, and when d23 is 1, 1≦d24+d25+d28+d34≦6. When d31 is 0, 0≦d32+d33≦4, and when d31 is 1, 0≦d32+d33≦6. Also, d24+d32≧1.

[0802] In equation (d3), 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 d25 is 2 or more, each R F1 They may be the same or different from each other. When d26 is 2 or more, each R F2 They may be the same or different from each other. When d27 is 2 or more, each R F3 They may be the same as or different from each other.

[0803] In equation (d3), R 41 ~R 44 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 (a), 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.

[0804] Also, when d28 is 2, the two R 41 The two Rs may be identical or different from each other. 41 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When d29 is 2, two R 42 The two Rs may be identical or different from each other. 42 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When d30 is 2, two R 43 The two Rs may be identical or different from each other. 43 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When d33 is 2, two R 44 The two Rs may be identical or different from each other. 44These 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.

[0805] Furthermore, S in the sulfonium cation represented by formula (d3) + 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.)

[0806] In equation (d3), L H1 and L H2 These are, independently, a single bond, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonic acid amide bond, a carbonate bond, or a carbamate bond. Of these, L H1 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. H2 The bond is preferably a single bond, an ether bond, or an ester bond, and more preferably a single bond.

[0807] In equation (d3), X L6This is a C1-C40 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. L6 A specific example of a C1-C40 hydrocarbylene group that may contain a heteroatom represented by the formula (Z) is X in the explanation of formula (Z). L1 and X L2 X is an example of a specific example of a C1-C40 hydrocarbylene group that may contain a heteroatom represented by the symbol X. L -0~X L -61 is one example. Of these, X L -0~X L -22, X L -29~X L -34 and X L -47~X L -61 is preferred.

[0808] The sulfonium cation represented by formula (d3) is preferably the one represented by formula (d3-1) below. [ka] (In the formula, d24~d30, d32~d34, R F1 ~R F3 , R 41 ~R 44 , L H1 , L H2 and X L6 (This is the same as above.)

[0809] The sulfonium cation represented by formula (d3-1) is preferably the one represented by formula (d3-2) below. [ka] (In the formula, d24~d30, R F1 ~R F3 and R 41 ~R 43 (This is the same as above.)

[0810] Specific examples of sulfonium cations represented by formula (d3) are listed below, but are not limited to these. In the following formula, Me represents a methyl group. [ka]

[0811] [ka]

[0812] [ka]

[0813] [ka]

[0814] [ka]

[0815] [ka]

[0816] [ka]

[0817] [ka]

[0818] [ka]

[0819] [ka]

[0820]

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[0821]

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[0822]

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[0823]

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[0824]

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[0825]

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[0826]

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[0827]

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[0828]

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[0829]

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[0830] [ka]

[0831] [ka]

[0832] [ka]

[0833] [ka]

[0834] [ka]

[0835] [ka]

[0836] [ka]

[0837] [ka]

[0838] The polymer preferably further contains a repeating unit represented by the following formula (e) (hereinafter also referred to as repeating unit e). [ka]

[0839] In formula (e), R A This is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1This consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-OZ 11 -or *-C(=O)-N(H)-Z 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. * represents a bond with a carbon atom of the main chain. Z 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. 51 This is a group having 1 to 20 carbon atoms that includes a hydrogen atom or at least one structure selected from a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic acid anhydride (-C(=O)-OC(=O)-).

[0840] Specific examples of repeating units e 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]

[0841] [ka]

[0842] [ka]

[0843] [ka]

[0844]

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[0845]

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[0846]

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[0847]

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[0848]

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[0849]

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[0850]

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[0851]

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[0852]

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[0853]

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[0854]

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[0855] [ka]

[0856] As for the repeating unit e, 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.

[0857] The polymer may contain repeating units (hereinafter also referred to as repeating unit f) having a structure in which a hydroxyl group is protected by an acid-unstable group. The repeating unit e 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 (f). [ka]

[0858] In formula (f), R A R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 61 R is a (e+1) valent hydrocarbon group having 1 to 30 carbon atoms, which may contain heteroatoms. 62 It is an acid-unstable group. e is 1, 2, 3, or 4.

[0859] In formula (f), R 62 The acid-unstable group represented by can be any group that is deprotected by the action of an acid and generates a hydroxyl group. 62 The structure is not particularly limited, but acetal structures, ketal structures, hydrocarbyloxycarbonyl groups, and hydrocarbyloxymethyl groups represented by the following formula (f1) are preferred, and the hydrocarbyloxymethyl group represented by the following formula (f1) is particularly preferred. [ka] (In the formula, * represents a bond. R 63 is a hydrocarbyl group having 1 to 15 carbon atoms.)

[0860] R 62 Examples of the acid-labile group represented by, the hydrocarbyloxymethyl group represented by the formula (f1), and the repeating unit f are the same as those exemplified in the description of the repeating unit d described in JP-A-2020-111564.

[0861] The polymer may contain a repeating unit g derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or a derivative thereof. Specific examples of the monomer that gives the repeating unit g include, but are not limited to, those shown below.

Chemical formula

[0862] The polymer may contain a repeating unit h derived from styrene, indane, vinylpyridine or vinylcarbazole.

[0863] In the polymer of the present invention, the content ratios of the repeating units a, b1, b2, b3, c, d, e, f, g and h are preferably 0 < a ≤ 0.4, 0 < b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 ≤ b3 ≤ 0.6, 0 < c ≤ 0.6, 0 ≤ d ≤ 0.4, 0 ≤ e ≤ 0.6, 0 ≤ f ≤ 0.3, 0 ≤ g ≤ 0.3 and 0 ≤ h ≤ 0.3, and more preferably 0 < a ≤ 0.3, 0 < b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 ≤ b3 ≤ 0.5, 0 < c ≤ 0.5, 0 ≤ d ≤ 0.3, 0 ≤ e ≤ 0.5, 0 ≤ f ≤ 0.2, 0 ≤ g ≤ 0.2 and 0 ≤ h ≤ 0.2. However, a + b1 + b2 + b3 + c + d + e + f + g + h ≤ 1.0.

[0864] 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.

[0865] 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.

[0866] 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.

[0867] 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.

[0868] 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.

[0869] 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.

[0870] 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.

[0871] 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.

[0872] 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.

[0873] 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.

[0874] 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.

[0875] 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.

[0876] 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.

[0877] 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.

[0878] [Chemically amplified resist composition] [(A) Base polymer] The chemically amplified resist composition of the present invention includes a base polymer containing the aforementioned polymer as component (A).

[0879] The aforementioned polymer may be used alone, or two or more polymers with different composition ratios, Mw, and / or Mw / Mn may be used in combination. In addition, the (A) base polymer may include hydrogenated ring-opening metathesis polymers in addition to the aforementioned polymers, and for this, those described in Japanese Patent Publication No. 2003-66612 may be used.

[0880] [(B) Organic solvents] The chemically amplified resist composition of the present invention may contain an organic solvent as component (B). The organic solvent (B) 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.

[0881] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, ethyl lactate, DAA, and mixed solvents thereof are preferred, as they exhibit particularly excellent solubility of the base polymer of component (A).

[0882] In the chemically amplified resist composition of the present invention, the content of (B) 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 (A) base polymer. (B) organic solvent may be used alone or as a mixture of two or more types.

[0883] [(C) Quencher] The chemical amplification resist composition of the present invention may contain a quencher as component (C). In the present invention, a quencher is a material that traps strong acids generated from the photoacid generator in the chemical amplification resist composition, thereby preventing their 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.

[0884] (C)Specific examples of quenchers include onium salts represented by the following formulas (1) or (2). [ka]

[0885] In formula (1), R q1 This is a C1-C40 hydrocarbyl group 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 (2), R q2 This is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a hydrogen atom or a heteroatom.

[0886] 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. As a result, the group may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0887] 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.

[0888] Specific examples of anions of onium salts represented by formula (1) are listed below, but are not limited to these. [ka]

[0889] [ka]

[0890] [ka]

[0891] [ka]

[0892] [ka]

[0893] Specific examples of anions of onium salts represented by formula (2) are listed below, but are not limited to these. [ka]

[0894] [ka]

[0895] [ka]

[0896] [ka]

[0897] [ka]

[0898] In equations (1) and (2), MQ + This is an onium cation. Preferably, the onium cation is a sulfonium cation, an iodonium cation, or an ammonium cation. Specific examples of the sulfonium cation include, but are not limited to, those similar to those exemplified as specific examples of cations of sulfonium salt type monomers represented by formula (a), 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, and those represented by formula (d3).

[0899] Specific examples of the iodonium cation mentioned above include, but are not limited to, those described in paragraph

[0181] of Japanese Patent Publication No. 2024-000259.

[0900] A specific example of the ammonium cation is the one represented by the following formula (am-1). [ka]

[0901] In formula (am-1), R q11 ~R q14 Each of these is independently a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. Also, R q11 and R q12 However, they may bond to each other and 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 (a). 1 ~R 3 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0902] Specific examples of ammonium cations represented by formula (am-1) are listed below, but are not limited to these. [ka]

[0903] Specific examples of onium salts represented by formula (1) or (2) 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.

[0904] The onium salt represented by formula (1) or (2) 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 refers to an acidity that does not deprotect the acid-unstable groups of the acid-unstable group-containing units used in the base polymer. The onium salt represented by formula (1) or (2) 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.

[0905] Furthermore, as the (C) 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.

[0906] 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.

[0907] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (1) or (2) as (C) 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 (A) 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 (1) or (2) may be used alone or in combination of two or more types.

[0908] The chemically amplified resist composition of the present invention may contain a nitrogen-containing compound as (C) 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.

[0909] 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.

[0910] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as (C) 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 (A) base polymer. The nitrogen-containing compound may be used alone or in combination of two or more types.

[0911] [(D) Acid Generator] The chemically amplified resist composition of the present invention may contain an acid generator, to the extent that it does not impair the effects of the present invention. Examples of the acid generator include compounds that generate acid in response to active light or radiation (photoacid generators). The photoacid generator is not particularly limited as long as it is a compound that generates acid upon irradiation with high-energy rays, but those that generate sulfonic acid, imido acid, or methidic acid are preferred. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc. Specific examples of acid generators are those described in paragraphs

[0122] to

[0142] of Japanese Patent Application Publication No. 2008-111103.

[0912] Furthermore, suitable photoacid generators include those represented by the following formulas (3) or (4). [ka]

[0913] In equations (3) and (4), 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 (A). 1 ~R 3 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0914] Specific examples of sulfonium salt cations represented by formula (3) include, but are not limited to, those exemplified as specific examples of sulfonium salt type monomer cations represented by formula (a), 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, those described in paragraphs

[0035] to

[0046] of Japanese Patent No. 7491173, and those exemplified as specific examples of sulfonium cations represented by formula (d3). Specific examples of iodonium salt cations represented by formula (4) include, but are not limited to, those described in paragraph

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

[0915] In equations (3) and (4), Xa - This is an anion of a strong acid. Examples of the strong acid anions include those represented by any of the following formulas (Xa-1) to (Xa-4). [ka]

[0916] In equation (Xa-1), R fa 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 (Xa-1-1) described later. fa1 Examples of hydrocarbyl groups represented by the symbol shown are similar to those exemplified.

[0917] The anion represented by formula (Xa-1) is preferably the one represented by the following formula (Xa-1-1). [ka]

[0918] In equation (Xa-1-1), Q 1 and Q 2Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, but to improve solvent solubility, it is preferable that at least one of them is a trifluoromethyl group. m is 0, 1, 2, 3, or 4, but it is particularly preferable that it is 1. R fa1 This is a hydrocarbyl group having 1 to 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.

[0919] In equation (Xa-1-1), R fa1 The 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, tetracyclododecylmethyl, and dicyclohexylmethyl. Examples include cyclic saturated hydrocarbyl groups with 3 to 40 carbon atoms, such as the tyl group; unsaturated aliphatic hydrocarbyl groups with 2 to 40 carbon atoms, such as the 2-propenyl group and the 3-cyclohexenyl group; aryl groups with 6 to 40 carbon atoms, such as the phenyl group, the 1-naphthyl group, the 2-naphthyl group, and the 9-fluorenyl group; aralkyl groups with 7 to 40 carbon atoms, such as the benzyl group and the diphenylmethyl group; aromatic ring-containing polycyclic hydrocarbyl groups with 7 to 40 carbon atoms, such as the 9,10-ethano-9,10-dihydroanthryl group and the 6,13-ethano-6,13-dihydropentacenyl group; hydrocarbyl groups with 17 to 40 carbon atoms having a steroid skeleton; and groups obtained by combining these.

[0920] 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.

[0921] In equation (Xa-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.

[0922] Specific examples of anions represented by formula (Xa-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]

[0923] [ka]

[0924] [ka]

[0925] [ka]

[0926] [ka]

[0927] [ka]

[0928] [ka]

[0929] [ka]

[0930] [ka]

[0931] [ka]

[0932] [ka]

[0933] [ka]

[0934] In equation (Xa-2), R fb1 and R fb2Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may independently contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (Xa-1-1). fa1 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fb1 and R fb2 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 However, they bond to each other and the group to which they bond (-CF2-SO2-N - It may form a ring with -SO2-CF2-), in which case R fb1 and R fb2 The groups obtained by the bonding of these groups are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0935] In equation (Xa-3), R fc1 , R fc2 and R fc3 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may independently contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (Xa-1-1). fa1 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fc1 , R fc2 and R fc3 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 However, they bond to each other and the group to which they bond (-CF2-SO2-C - It may form a ring with -SO2-CF2-), in which case R fc1 and R fc2 The groups obtained by the bonding of these groups are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0936] In equation (Xa-4), R fdR 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 (Xa-1-1). fa1 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.

[0937] Specific examples of anions represented by formula (Xa-4) are listed below, but are not limited to these. [ka]

[0938] [ka]

[0939] Further examples of the aforementioned non-nucleophilic counterions include anions having an aromatic ring substituted with an iodine or bromine atom. A specific example of such anion is represented by the following formula (Xa-5). [ka]

[0940] In equation (Xa-5), 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.

[0941] In equation (Xa-5), 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.

[0942] In equation (Xa-5), L 11 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.

[0943] In equation (Xa-5), L 12 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.

[0944] L 12 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 2,6Examples 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. 12 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.

[0945] 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.

[0946] In equation (Xa-5), L 13 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, or carbamate bonds.

[0947] In equation (Xa-5), R feThis includes hydroxyl groups, carboxyl groups, fluorine atoms, chlorine atoms, bromine atoms, amino groups, C1-C20 hydrocarbyl groups, C1-C20 hydrocarbyloxy groups, C1-C20 hydrocarbylthio groups, C2-C20 hydrocarbylcarbonyl groups, C2-C20 hydrocarbyloxycarbonyl groups, C2-C20 hydrocarbylcarbonyloxy groups, or C1-C20 hydrocarbylsulfonyloxy groups, -N(R feA )(R feB ), -N(R feC )-C(=O)-R feD or -N(R feC )-C(=O)-OR feD 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. feA and R feB Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. feC R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. feDThis 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 fe They may be the same as or different from each other.

[0948] Of these, R fe Examples include hydroxyl groups, -N(R feC )-C(=O)-R feD , -N(R feC )-C(=O)-OR feD Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc. are preferred.

[0949] In formula (Xa-5), Rf 11 ~Rf 14 Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of these is either a fluorine atom or a trifluoromethyl group. Also, Rf 11 and Rf 12 These may combine to form a carbonyl group. In particular, Rf 13 and Rf 14 It is preferable that both are fluorine atoms.

[0950] Specific examples of anions represented by formula (Xa-5) are listed below, but are not limited to these. Note that in the following formula, X BI This is the same as described above. [ka]

[0951]

change

[0952]

change

[0953]

change

[0954]

change

[0955]

change

[0956]

change

[0957]

change

[0958]

change

[0959]

change

[0960]

change

[0961]

change

[0962]

change

[0963]

change

[0964]

change

[0965]

change

[0966]

change

[0967]

change

[0968]

change

[0969]

change

[0970]

change

[0971]

change

[0972]

Chem.

[0973]

Chem.

[0974] Xa -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.

[0975] As the non-nucleophilic counterions, the following can also be used: a fluorobenzenesulfonic acid anion bonded to an aromatic group containing an iodine atom, as described in Japanese Patent No. 6648726; an anion having a mechanism for decomposition by acid, as described in International Publication No. 2021 / 200056 and Japanese Patent Application Publication No. 2021-70692; an anion having a cyclic ether group, as described in Japanese Patent Application Publication No. 2018-180525 and Japanese Patent Application Publication No. 2021-35935; and an anion described in Japanese Patent Application Publication No. 2018-92159.

[0976] As the non-nucleophilic counterions, anions of bulky benzenesulfonic acid derivatives that do not contain fluorine atoms, as described in Japanese Patent Publication No. 2006-276759, Japanese Patent Publication No. 2015-117200, Japanese Patent Publication No. 2016-65016, Japanese Patent Publication No. 2019-202974, and Japanese Patent Publication No. 2024-104830, as well as benzenesulfonic acid anions and alkylsulfonic acid anions that do not contain fluorine atoms bonded to an aromatic group containing an iodine atom, as described in Japanese Patent Publication No. 6645464. Furthermore, anions described in

[0229] to

[0231] of Japanese Patent Publication No. 2024-77330 and

[0033] to

[0093] of Japanese Patent Publication No. 2024-140135 can also be used.

[0977] 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.

[0978] Furthermore, as the photoacid generator for component (D), one represented by the following formula (5) is also preferred. [ka]

[0979] In formula (5), 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.

[0980] 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.

[0981] 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.

[0982] In formula (5), 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.

[0983] In formula (5), 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.

[0984] The photoacid generator represented by formula (5) is preferably the one represented by the following formula (5'). [ka]

[0985] In formula (5'), 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 (Xa-1-1). fa1 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.

[0986] Specific examples of the photoacid generator represented by formula (5) include those similar to those exemplified as the photoacid generator represented by formula (2) in Japanese Patent Publication No. 2017-26980.

[0987] Among the photoacid generators, those containing an anion represented by formula (Xa-1-1) or (Xa-4) are particularly preferred because they exhibit low acid diffusion and excellent solubility in solvents. Furthermore, those represented by formula (5') are particularly preferred because they exhibit extremely low acid diffusion.

[0988] If the chemically amplified resist composition of the present invention contains (D) a photoacid generator, its content is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass, per 80 parts by mass of the (A) base polymer. When the amount of (D) photoacid generator added is within the above range, the resolution is good and there is no risk of foreign matter problems occurring after development or peeling of the resist film, so it is preferable. (D) The photoacid generator may be used alone or in combination of two or more types.

[0989] [(E) Surfactants] The chemically amplified resist composition of the present invention may further contain a surfactant as component (E). Preferably, the surfactant (E) 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.

[0990] 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]

[0991] 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.)

[0992] Among these, the 1,4-butylene group and the 2,2-dimethyl-1,3-propylene group are preferred.

[0993] 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.

[0994] 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.

[0995] 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 (6A) (hereinafter also referred to as repeating unit 6A), the repeating unit represented by formula (6B) (hereinafter also referred to as repeating unit 6B), the repeating unit represented by formula (6C) (hereinafter also referred to as repeating unit 6C), the repeating unit represented by formula (6D) (hereinafter also referred to as repeating unit 6D), and the repeating unit represented by formula (6E) (hereinafter also referred to as repeating unit 6E). [ka]

[0996] In formulas (6A) to (6E), 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.

[0997] 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.

[0998] 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.

[0999] 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 Specific examples of fluorinated hydrocarbyl groups represented by the formula include groups in which some or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbyl group are replaced with fluorine atoms. As mentioned above, ether bonds or carbonyl groups may be interposed between these carbon-carbon bonds.

[1000] 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.

[1001] 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.

[1002] 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.

[1003] Specific examples of repeating units 6A to 6E 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]

[1004] [ka]

[1005] [ka]

[1006] [ka]

[1007] [ka]

[1008] [ka]

[1009] The polymer-type surfactant may further contain other repeating units besides repeating units 6A to 6E. Specific examples of other repeating units include repeating units obtained from methacrylic acid or α-trifluoromethylacrylic acid derivatives. The content of repeating units 6A to 6E 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.

[1010] 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.

[1011] 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 6A to 6E, 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.

[1012] 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.

[1013] If the chemically amplified resist composition of the present invention contains (E) a surfactant, 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 (A) base polymer. If the content of (E) surfactant 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. (E) surfactant may be used alone or in combination of two or more types.

[1014] [(F) Dissolution inhibitor] The chemically amplified resist composition of the present invention may further contain a dissolution inhibitor as component (F). When the chemically amplified resist composition of the present invention is of the positive type, the difference in dissolution rate between the exposed and unexposed areas can be further increased by incorporating a dissolution inhibitor, thereby further improving the resolution.

[1015] Specific examples of the dissolution inhibitor include compounds having a molecular weight of preferably 100 to 1000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule, in which the hydrogen atoms of the phenolic hydroxyl groups are substituted with acid-unstable groups in a proportion of 0 to 100 mol% overall, or compounds containing a carboxyl group in the molecule, in which the hydrogen atoms of the carboxyl group are substituted with acid-unstable groups in an average proportion of 50 to 100 mol overall. Specifically, examples include compounds in which the hydrogen atoms of the hydroxyl group or carboxyl group of bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalenecarboxylic acid, adamantanecarboxylic acid, and cholic acid are substituted with acid-unstable groups, and for example, those described in paragraphs

[0155] to

[0178] of Japanese Patent Application Publication No. 2008-122932.

[1016] If the chemically amplified resist composition of the present invention contains (F) a dissolution inhibitor, its content is preferably 0 to 50 parts by mass, and more preferably 5 to 40 parts by mass, per 80 parts by mass of the (A) base polymer. The (F) dissolution inhibitor may be used alone or in combination of two or more types.

[1017] [(G) Other ingredients] The chemically amplified resist composition of the present invention may include, as (G) other components, compounds that decompose with acid to generate acid (acid-generating compounds), organic acid derivatives, fluorine-substituted alcohols, water-repellency enhancers, etc. As the acid-generating compounds, compounds described in Japanese Patent Publication No. 2009-269953 or Japanese Patent Publication No. 2010-215608 can be referenced. When the acid-generating compounds are included, their 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 (A) 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 derivatives and fluorine-substituted alcohols, compounds described in Japanese Patent Publication No. 2009-269953 or Japanese Patent Publication No. 2010-215608 can be referenced.

[1018] The water-repellent enhancer can be used in immersion lithography without a topcoat. Preferred water-repellent enhancers include polymers containing alkyl fluoride, polymers containing 1,1,1,3,3,3-hexafluoro-2-propanol residues of a specific structure, and those exemplified in Japanese Patent Publication No. 2007-297590 and Japanese Patent Publication No. 2008-111103 are more preferred. The water-repellent enhancer needs to be soluble in an alkaline developer or an organic solvent developer. The aforementioned water-repellent enhancer having a specific 1,1,1,3,3,3-hexafluoro-2-propanol residue exhibits good solubility in the developer. As a water-repellent enhancer, polymers containing repeating units including amino groups or amine salts are highly effective in preventing acid evaporation in the PEB and thus preventing poor hole pattern opening after development. If the chemically amplified resist composition of the present invention contains the water-repellency improving agent, its content is preferably 0 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass, per 80 parts by mass of the (A) base polymer.

[1019] [Pattern formation method] When the chemically amplified resist composition of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied. For example, a pattern formation method may include a step of forming a resist film on a substrate using the chemically amplified resist composition described above, a step of exposing the resist film with high-energy rays, and a step of developing the exposed resist film using a developer.

[1020] First, the chemically amplified resist composition of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, so that the coating film thickness is 0.01 to 2.0 μm. This is then pre-baked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[1021] Next, the resist film is exposed using high-energy rays. Examples of high-energy rays include ultraviolet rays, far-ultraviolet rays, EB rays, EUV rays with wavelengths of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When using ultraviolet rays, far-ultraviolet rays, EUV rays, X-rays, soft X-rays, excimer laser light, gamma rays, or synchrotron radiation as the high-energy rays, the exposure amount is preferably 1 to 200 mJ / cm², either directly or using a mask to form the desired pattern. 2 To the extent, more preferably 10 to 100 mJ / cm² 2 Irradiate to the extent of the above. When using EB as the high-energy beam, the exposure dose is preferably 0.1 to 100 μC / cm². 2 To a degree, more preferably 0.5 to 50 μC / cm² 2 The pattern is drawn either directly or using a mask to form the desired pattern. The chemically amplified resist composition of the present invention is particularly suitable for fine patterning using high-energy rays, including ArF excimer laser light with a wavelength of 193 nm, KrF excimer laser light with a wavelength of 248 nm, EB, or EUV, X-rays, soft X-rays, gamma rays, or synchrotron radiation with wavelengths of 3 to 15 nm.

[1022] After exposure, PEB may be performed on a hot plate at a temperature of preferably 60-150°C for 10 seconds to 30 minutes, more preferably at 80-120°C for 30 seconds to 20 minutes.

[1023] After exposure or PEB, development is performed using a developer solution containing 0.1 to 10% by mass, preferably 2 to 5% by mass, of an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by conventional methods such as the dip method, puddle method, or spray method. The areas irradiated with light dissolve in the developer solution, while the areas not exposed do not dissolve, forming the desired positive-type pattern on the substrate.

[1024] Negative patterns can also be obtained using an organic solvent developer instead of the aforementioned alkaline aqueous solution. Specific examples of developers used in this case include 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, and ethyl crotate. Examples include methyl propionate, 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, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenyl acetate, and 2-phenylethyl acetate. These organic solvents may be used individually or in mixtures of two or more.

[1025] Rinsing may be performed at the end of development. A solvent that mixes with the developer but does not dissolve the resist film is preferred as the rinsing solution. Preferred solvents include C3-C10 alcohols, C8-C12 ether compounds, C6-C12 alkanes, alkenes, alkynes, and aromatic solvents.

[1026] Specific examples of the C3-C10 alcohols include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, and 3-hexanol. Examples include 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, and others.

[1027] Specific examples of the ether compounds having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, and di-n-hexyl ether.

[1028] Specific examples of the C6-C12 alkanes include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Specific examples of the C6-C12 alkenes include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Specific examples of the C6-C12 alkynes include hexine, heptine, and octine.

[1029] Specific examples of the aromatic solvents mentioned above include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[1030] Rinsing can reduce the occurrence of resist pattern deformation and defects. However, rinsing is not always necessary, and omitting it can reduce the amount of solvent used.

[1031] The developed hole patterns and trench patterns can also be shrunk using thermal flow, RELACS, or DSA techniques. A shrinking agent is applied to the hole pattern, and crosslinking of the shrinking agent occurs on the surface of the resist film due to the diffusion of an acid catalyst from the resist film during baking, causing the shrinking agent to adhere to the side walls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, during which excess shrinking agent is removed and the hole pattern is reduced in size. [Examples]

[1032] 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.

[1033] [1] Synthesis of sulfonium salt type monomers [Example 1-1] Synthesis of sulfonium salt type monomer a-1 (1) Synthesis of intermediate In-1 [ka]

[1034] Under a nitrogen atmosphere, the Grignard reagent was prepared according to a conventional method using chlorobenzene (67.5 g), metallic magnesium (14.6 g), and THF (400 g). The reaction mixture was then cooled to below 10°C, and a solution consisting of compound SM-1 (90.9 g) and THF (90 g) was added. Furthermore, trimethylsilyl chloride (65.2 g) was added dropwise at an internal temperature of below 20°C. After addition, the mixture was aged for 3 hours at an internal temperature of below 20°C. After aging, saturated ammonium chloride aqueous solution (500 g) was added dropwise to stop the reaction. Then, methylene chloride (500 g) was added to separate the organic layer, which was washed with water, and then concentrated under reduced pressure to remove the solvent. The residue was purified by silica gel column chromatography to obtain 89.3 g of intermediate In-1 as a colorless oil (yield 81%).

[1035] (2) Synthesis of sulfonium salt type monomer a-1 [ka]

[1036] Under a nitrogen atmosphere, intermediate In-1 (55.1 g), intermediate In-2 (57.8 g), methyl isobutyl ketone (300 g), and water (150 g) were charged and stirred at room temperature for 30 minutes. The organic layer was separated, washed with water, and then concentrated under reduced pressure. The residue was purified by silica gel column chromatography to obtain 98.4 g of monomer a-1 as an oily substance (yield 92%).

[1037] The TOF-MS results for sulfonium salt monomer a-1 are shown below. MALDI TOF-MS: POSITIVE M + 515(C 26 H 28 F5OS2 + equivalent) NEGATIVE M - 555(C 15 H9I2O5S - equivalent)

[1038] [Examples 1-2 to 1-7] Synthesis of sulfonium salt type monomers a-2 to a-7 Using corresponding raw materials and known organic synthesis reactions, sulfonium salt type monomers a-2 to a-7, represented by the following formulas, were synthesized. [ka]

[1039] [Comparative Examples 1-1 to 1-5] Synthesis of Comparative Onium Salt Type Monomers Ca-1 to Ca-5 Using corresponding raw materials and known organic synthesis reactions, comparative onium salt monomers Ca-1 to Ca-5, represented by the following formulas, were synthesized. [ka]

[1040] [2] Synthesis of base polymers The monomers used in the synthesis of the base polymer, excluding monomers a-1 to a-7 and comparative monomers ca-1 to ca-5, are as follows: [ka]

[1041] [ka]

[1042] [ka]

[1043] [ka]

[1044] [ka]

[1045] [Example 2-1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, monomer a-1 (14.0 g), monomer b1-1 (29.2 g), monomer c-1 (9.4 g), monomer d-1 (47.6 g), V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 3.01 g, and MEK 140 g were placed in a flask to prepare a monomer-polymerization initiator solution. In another flask under a nitrogen atmosphere, 46 g of MEK was placed and heated to 80°C with stirring, and then the monomer-polymerization initiator solution was added dropwise over 4 hours. After the addition was complete, stirring was continued for 2 hours while maintaining the temperature of the polymerization solution at 80°C, and then it was cooled to room temperature. The obtained polymerization solution was added dropwise to 3000 g of hexane that had been vigorously stirred, and the precipitated polymer was filtered off. The obtained polymer was washed twice with 600 g of hexane, and then vacuum dried at 50°C for 20 hours to obtain a white powdery polymer P-1 (yield 97.1 g, yield 97%). The Mw of polymer P-1 was 10100, and the Mw / Mn ratio was 1.55. Note that Mw is a polystyrene-converted value measured by GPC using DMF as the solvent. [ka]

[1046] [Examples 2-2 to 2-50, Comparative Examples 2-1 to 2-38] Synthesis of polymers P-2 to P-50 and comparative polymers CP-1 to CP-38 The polymers shown in Tables 1-3 were produced using the same method as in Synthesis Example 2-1, except that the types and mixing ratios of each monomer were changed.

[1047] [Table 1]

[1048] [Table 2]

[1049] [Table 3]

[1050] [3] Preparation of chemically amplified resist compositions [Examples 3-1 to 3-53, Comparative Examples 3-1 to 3-40] A predetermined component selected from the base polymers (P-1 to P-50) of the present invention, comparative base polymers (CP-1 to CP-38), acid generators (PAG-1, PAG-2), and quenchers (SQ-1, AQ-1) was dissolved in a solvent containing 0.01% by mass of FC-4430 manufactured by 3M as a surfactant, in the compositions shown in Tables 4 to 6 below, to prepare a solution. This solution was then filtered through a 0.2 μm Teflon® type filter to prepare chemically amplified resist compositions (R-1 to R-53, CR-1 to CR-40).

[1051] [Table 4]

[1052] [Table 5]

[1053] [Table 6]

[1054] In Tables 4-6, the solvents, quenchers (SQ-1, AQ-1), and acid generators (PAG-1, PAG-2) are as follows: • Solvent: PGMEA (Propylene glycol monomethyl ether acetate) EL (Ethyl Lactate) DAA (Diacetone Alcohol)

[1055] • Quencher: SQ-1, AQ-1 [ka]

[1056] • Acid generators: PAG-1, PAG-2, PAG-3 [ka]

[1057] [4] EUV lithography evaluation (1) [Examples 4-1 to 4-53, Comparative Examples 4-1 to 4-40] Each chemically amplified resist composition (R-1 to R-53, CR-1 to CR-40) shown in Tables 4 to 6 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 NXE3300 (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 7-9. 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-Tech Corporation length-measuring SEM (CG6300), and sensitivity, EL, LWR, 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 7-9.

[1058] [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.

[1059] [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.

[1060] [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.

[1061] [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.

[1062] [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.

[1063] [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. 2The 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.

[1064] [Table 7]

[1065] [Table 8]

[1066] [Table 9]

[1067] The results shown in Tables 7-9 demonstrate that the chemically amplified resist composition using a base polymer containing repeating units derived from the onium salt monomer of the present invention exhibits excellent EL, LWR, and DOF with good sensitivity. Furthermore, it was confirmed that the tilt limit value is small and that the pattern is resistant to tilting even in the formation of fine patterns. Moreover, it was confirmed that development defects are suppressed. Therefore, the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[1068] [5] EUV Lithography Evaluation (2) [Examples 5-1 to 5-53, Comparative Examples 5-1 to 5-40] Each chemically amplified resist composition (R-1 to R-53, CR-1 to CR-10) shown in Tables 4 to 6 was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. had been formed to a thickness of 20 nm. The resist film was then pre-baked at 105°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. The resist film was exposed using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, wafer-mounted dimensions of 46 nm pitch, +20% bias hole pattern mask). PEB was performed using a hot plate at the temperatures listed in Tables 7 and 8 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 10-12.

[1069] [Table 10]

[1070] [Table 11]

[1071] [Table 12]

[1072] The results shown in Tables 10-12 confirm that the chemically amplified resist composition of the present invention exhibits good sensitivity and excellent CDU.

[1073] [6] Dry etching resistance evaluation [Examples 6-1 to 6-50, Comparative Examples 6-1 to 6-38] Two g each of the polymers shown in Tables 1 and 2 (polymers P-1 to P-50, comparative polymers CP-1 to CP-10) was dissolved in 10 g of cyclohexanone, filtered through a 0.2 μm size filter, and the resulting polymer solution was spin-coated onto a Si substrate to a thickness of 300 nm. The films were then evaluated under the following conditions. Etching test with CHF3 / CF4 gas: The difference in polymer film thickness before and after etching was determined using the TE-8500P dry etching system manufactured by Tokyo Electron Ltd. The etching conditions are as follows: Chamber pressure 40 Pa RF Power 1000W Gap 9mm CHF3 gas flow rate: 30 mL / min CF4 gas flow rate: 30 mL / min Ar gas flow rate: 100 mL / min Time 60sec This evaluation indicates that materials with less film thickness variation, i.e., those with less reduction in film thickness, have higher etching resistance. The results of the dry etching resistance are shown in Tables 13-15.

[1074] [Table 13]

[1075] [Table 14]

[1076] [Table 15]

[1077] The results shown in Tables 13-15 confirm that the polymer of the present invention has excellent dry etching resistance to CHF3 / CF4 gases.

Claims

1. A sulfonium salt type monomer represented by the following formula (a). 【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 - It is a carboxylic acid anion having an aromatic vinyl structure and an iodine atom.

2. The sulfonium salt type monomer according to claim 1, which is represented by the following formula (a1). 【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 type monomer according to claim 1, wherein the anion is represented by the following formula (Z). 【Chemistry 4】 (In the formula, m1 is 0 or 1. m2 is 0, 1, 2, 3 or 4. m3 is 0, 1, 2 or 3. m4 is 0 or 1. m5 is 0, 1, 2, 3 or 4. m6 is 0, 1, 2 or 3. m7 is 0 or 1. m8 is 1, 2, 3 or 4. m9 is 0, 1, 2 or 3. m10 is 0 or 1. m11 is 0 or The answer is 1. However, when m1 is 0, 0 ≤ m2 + m3 + m11 ≤ 4, and when m1 is 1, 0 ≤ m2 + m3 + m11 ≤ 6. When m4 is 0, 0 ≤ m5 + m6 ≤ 4, and when m4 is 1, 0 ≤ m5 + m6 ≤ 6. When m7 is 0, 0 ≤ m8 + m9 ≤ 5, and when m7 is 1, 0 ≤ m8 + m9 ≤ 7. Also, 1 ≤ m2 + m5 + m8 ≤ 4. R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 4 , R 5 and R 6 Each of these is independently a halogen atom other than an iodine atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl 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 C1-C20 hydrocarbylthio group which may contain a heteroatom, or a C1-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. When m3 is 2 or 3, each R 4 The two Rs may be the same or different from each other. 4 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When m6 is 2 or 3, each R 5 The two Rs may be the same or different from each other. 5 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When m9 is 2 or 3, each R 6 The two Rs may be the same or different from each other. 6 These atoms may bond with each other to form a ring with the carbon atoms to which they are bonded. L A1 , L A2 , L B1 and L B2 These are, independently, a single bond, an ether bond, a carbonyl group, an ester bond, a sulfonic acid ester bond, an amide bond, a sulfonic acid amide bond, a carbonate bond, or a carbamate bond. X L1 and X L2 Each of these is a hydroxylene group having 1 to 40 carbon atoms, which may contain single bonds or heteroatoms.

5. A sulfonium salt type quencher comprising a sulfonium salt type monomer according to any one of claims 1 to 4.

6. A polymer comprising repeating units derived from the sulfonium salt type quencher described in claim 5.

7. Furthermore, the polymer according to claim 6 comprises at least one selected from the repeating units represented by the following formula (b1), the repeating unit represented by the following formula (b2), and the repeating unit represented by the following formula (b3). 【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 consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-O-X 11 - or * - C(=O) - N(H) - 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 These are single bonds, *-C(=O)-O-, or *-C(=O)-N(H)-. * represents a bond with a carbon atom in the main chain. R 11 This 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. When a1 is 2, 3, or 4, each R 11 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 12 and R 13 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom. Also, R 12 and R 13 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. R 14 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 14A )(R 14B ). R 14A and R 14B are each independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. When b2 is 2 or more, each R 14 may be the same as or different from each other, and a plurality of R 14 may combine with each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached. )

8. Furthermore, the polymer according to claim 6, comprising a repeating unit represented by the following formula (c). 【Transformation 7】 (In the formula, R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y 1 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. R 21 This includes 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. c1 is 1, 2, 3, or 4. c2 is 0, 1, 2, or 3, where 1 ≤ c1 + c2 ≤ 5.

9. Furthermore, the polymer according to claim 6 comprises repeating units derived from an onium salt type monomer containing a polymerizable group and a fluorosulfonic acid anion having at least one iodine atom, and a sulfonium cation.

10. Furthermore, the polymer according to claim 6, comprising a repeating unit represented by the following formula (e). 【Transformation 8】 (wherein, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.) Z 1 This consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-O-Z. 11 - or * - C(=O) - N(H) - Z 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. * represents a bond with a carbon atom of the main chain. Z 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. R 51 This is a group having 1 to 20 carbon atoms that includes at least one structure selected from a hydrogen atom, or 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)-).

11. (A) A chemically amplified resist composition comprising a base polymer containing the polymer described in claim 6.

12. Furthermore, the chemically amplified resist composition according to claim 11, further comprising (B) an organic solvent.

13. Furthermore, the chemically amplified resist composition according to claim 11, further comprising (C) a quencher.

14. Furthermore, the chemically amplified resist composition according to claim 11, further comprising (D) an acid generator.

15. Furthermore, the chemically amplified resist composition according to claim 11, further comprising (E) a surfactant.

16. A pattern forming method comprising the steps of: forming a resist film on a substrate using the chemically amplified resist composition according to claim 11; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer.

17. The pattern forming method according to claim 16, wherein the high-energy beam is ArF excimer laser light with a wavelength of 193 nm or KrF excimer laser light with a wavelength of 248 nm, an electron beam or extreme ultraviolet light with a wavelength of 3 to 15 nm.

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