Onium salt, chemically amplified resist composition and pattern forming method

Abstract

To provide a chemically amplified resist composition that has improved lithography performance factors such as CDU, LWR and DOF and reduced defects in photolithography using high-energy radiation as the energy source, an acid diffusion inhibitor for use in the resist composition and a patterning process using the resist composition.SOLUTION: The present invention discloses an onium salt having the formula (1): wherein X is a sulfur atom or an iodine atom, n is 0 or 1, R1 is a hydrocarbyl group which may contain a fluorine atom or an oxygen atom, R2 and R3 are each independently a hydrocarbyl group which may contain a heteroatom, two of R2, R3 and Ar may bond together to form a ring with X to which they are attached, Ar is a C6-C14 arylene group which may be substituted with a predetermined substituent, Z- is a carboxylate, sulfonamide, sulfonimide or methide anion.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an onium salt, a chemically amplified resist composition, and a method of forming a pattern. [Background technology]

[0002] In recent years, with the increasing integration and speed of LSIs, finer pattern rules are required, and high-resolution resist patterns are required. As a result, there is an increasing need to improve not only lithography characteristics such as pattern shape, contrast, Mask Error Factor (MEF), Depth of Focus (DOF), Line Width Roughness (LWR), and Critical Dimension Uniformity (CDU), but also defects in the resist pattern after development.

[0003] One of the factors that cause defects and DOF degradation is the cations used in photoacid generators and acid diffusion inhibitors. Sulfonium cations and iodonium cations produce nonionic sulfides and iodinated arenes as decomposition products after exposure. These exposure decomposition products are highly lipid-soluble and therefore have low solubility in alkaline developers, and the photodecomposition reaction of the cations itself is a polarity change that reduces contrast, which is thought to lead to deterioration of lithography performance.

[0004] In order to suppress the influence of the exposure decomposition products of the cation on the lithography performance, for example, Patent Document 1 discloses the introduction of an acid labile group into the cation as shown in the following formula. In addition, Patent Document 2 proposes a compound that decomposes with an alkali to generate a phenol group as a photoacid generator. However, even when these compounds are used as photoacid generators or acid diffusion inhibitors, satisfactory results have not been obtained in various lithography performances in the generation requiring ultrafine processing using ArF lithography or extreme ultraviolet (EUV) lithography. [ka] [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5542402 [Patent Document 2] Patent No. 6169848 Summary of the Invention [Problem to be solved by the invention]

[0006] In response to recent demands for high-resolution resist patterns, resist compositions using conventional acid diffusion inhibitors may not necessarily satisfy lithography performance such as CDU, LWR, and DOF.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a chemically amplified resist composition that has excellent lithographic performance such as CDU, LWR, and DOF and has few defects in photolithography using a high-energy ray such as KrF excimer laser light, ArF excimer laser light, electron beam (EB), or EUV as a light source; an acid diffusion inhibitor for use in the resist composition; and a pattern formation method that uses the resist composition. [Means for solving the problem]

[0008] As a result of extensive investigations to achieve the above-mentioned object, the inventors have discovered that a chemically amplified resist composition that uses an onium salt of a specific structure as an acid diffusion inhibitor has few defects and is excellent in lithography performance such as CDU, LWR, and DOF, and is extremely effective as a resist composition for precise microfabrication, which has led to the completion of the present invention.

[0009] That is, the present invention provides the following onium salt, resist composition, and pattern forming method. 1. An onium salt represented by the following formula (1): [ka] (In the formula, X is a sulfur atom or an iodine atom. n is 1 when X is a sulfur atom, and is 0 when X is an iodine atom. R 1 is a hydrocarbyl group having 1 to 5 carbon atoms, and the hydrocarbyl group may contain a fluorine atom or an oxygen atom. R 2 and R 3 are each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 2 and R 3 may be bonded to each other to form a ring together with the X to which they are attached. Ar is an arylene group having 6 to 14 carbon atoms, and is selected from the group consisting of a halogen atom, a hydroxy group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, and a aryl group having 2 to 10 carbon atoms which may contain a heteroatom. 0 The hydrocarbylcarbonyloxy group may be substituted with a substituent selected from the group consisting of the hydrocarbylcarbonyloxy groups represented by R 2 and Ar may be bonded to each other to form a ring together with X to which they are attached. Z - is a carboxylate anion, a sulfonamide anion, a sulfonimide anion, or a methide anion. 2. An onium salt of 1 represented by the following formula (2): [ka] (In the formula, R 1 , R 2 , R 3 , n, X and Z - is the same as above. R 4represents a halogen atom, a hydroxy group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, or a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. m is an integer from 0 to 4. 3.R 1 is a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a 1-trifluoromethyl-2,2,2-trifluoroethyl group, or a 2-methoxyethyl group. 4.Z - is a carboxylate anion having one or more fluorine atoms or trifluoromethyl groups at the α- or β-position of the carboxyl group. 5.Z - is an anion represented by any one of the following formulas (Z-1) to (Z-5): [ka] (In the formula, R 11 is a perfluoroalkyl group having 1 to 4 carbon atoms. R 12 and R 13 are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, provided that R 12 and R 13 At least one of the groups is a fluorine atom or a trifluoromethyl group. R 14 and R 15 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 15 carbon atoms which may contain a heteroatom. R 16 , R 17 and R 18are each independently a hydrogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. L 1 and L 2 are each independently a single bond, a carbonyl group, or a sulfonyl group. 6. An acid diffusion inhibitor comprising any one of the onium salts of 1 to 5. 7. A chemically amplified resist composition comprising (A) a base polymer, (B) a photoacid generator, (C-1) an acid diffusion inhibitor of 6, and (D) an organic solvent. 8. A chemically amplified resist composition comprising (A') a base polymer having the function of generating acid upon exposure, (C-1) an acid diffusion inhibitor 6, and (D) an organic solvent. 9. The chemically amplified resist composition of 7 or 8, wherein the base polymer is a polymer containing a repeating unit represented by the following formula (a) or a repeating unit represented by the following formula (b): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. X A is a single bond, a phenylene group, a naphthylene group, or (main chain)-C(=O)-OX A1 - X A1 is a hydrocarbylene group having 1 to 15 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring. X B is a single bond or an ester bond. AL 1 and A.L. 2 are each independently an acid labile group. 10. The chemically amplified resist composition according to 9, wherein the acid labile group is a group represented by the following formula (L1): [ka] (In the formula, R 21represents a hydrocarbyl group having 1 to 7 carbon atoms, in which -CH2- may be replaced by -O-. a is 1 or 2. The dashed line represents a bond. 11. The chemically amplified resist composition according to any one of 7 to 10, wherein the base polymer is a polymer containing a repeating unit represented by the following formula (c): [ka] (In the formula, R A is a hydrogen atom or a methyl group. Y A is a single bond or an ester bond. R 22 is a fluorine atom, an iodine atom, a carboxy group, a formyl group, a formyloxy group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. b and c are integers satisfying 1≦b≦5, 0≦c≦4, and 1≦b+c≦5. 12. The chemically amplified resist composition according to 8, wherein the repeating unit capable of generating an acid upon exposure is represented by any one of the following formulas (d1) to (d4): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. R f1 , R f2 and R f3 are each independently a hydrogen atom or a trifluoromethyl group. Z A and Z B each independently represents a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. Z Cis a single bond, -Z C1 -, -OZ C1 - or -C(=O)-OZ C1 -It is. C1 is a phenylene group which is optionally substituted with a hydroxy group, a fluorine atom, an iodine atom, a trifluoromethyl group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, or a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. Z D is a single bond, a phenylene group, -OZ D1 -, -C(=O)-OZ D1 - or -C(=O)-NH-Z D1 -It is. D1 is a hydrocarbylene group which may contain a heteroatom. R 31 ~R 41 are each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 31 and R 32 , R 34 and R 35 , R 37 and R 38 or R 40 and R 41 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. k 1 is 0 or 1, but Z A When is a single bond, it is 0. 2 is 0 or 1, but Z B is 0 when it is a single bond. Xa - is a non-nucleophilic counterion. 13. A pattern forming method comprising the steps of forming a resist film on a substrate using any one of the chemically amplified resist compositions according to any one of claims 7 to 12, exposing the resist film to KrF excimer laser light or ArF excimer laser light, and developing the exposed resist film using a developer. 14. A pattern forming method comprising the steps of applying any one of the chemically amplified resist compositions of 7 to 12 onto a substrate, exposing the resist film to EB or EUV, and developing the exposed resist film using a developer. 15. The pattern forming method according to 13 or 14, wherein an alkaline aqueous solution is used as a developer to dissolve exposed areas and to obtain a positive pattern in which unexposed areas do not dissolve. 16. The pattern forming method according to 13 or 14, wherein an organic solvent is used as a developer to dissolve the unexposed areas and obtain a negative pattern in which the exposed areas do not dissolve. Effect of the Invention

[0010] When a pattern is formed using a resist composition containing the onium salt of the present invention as an acid diffusion inhibitor, it is possible to form a pattern that is excellent in lithography performance such as CDU, LWR, and DOF and has few defects. [Brief description of the drawings]

[0011] [Figure 1] 1 is a 1H-NMR spectrum of the acid diffusion inhibitor Q-1 obtained in Example 1-1. [Diagram 2] 1 is a 19F-NMR spectrum of the acid diffusion inhibitor Q-1 obtained in Example 1-1. [Diagram 3] 1 is a 1H-NMR spectrum of the acid diffusion inhibitor Q-2 obtained in Example 1-2. [Figure 4] 1 is a 19F-NMR spectrum of the acid diffusion inhibitor Q-2 obtained in Example 1-2. [Diagram 5] 1 is a 1H-NMR spectrum of the acid diffusion inhibitor Q-3 obtained in Example 1-3. [Figure 6] 1 is a 19F-NMR spectrum of the acid diffusion inhibitor Q-3 obtained in Example 1-3. [Figure 7] 1 is a 1H-NMR spectrum of the acid diffusion inhibitor Q-4 obtained in Example 1-4. [Figure 8] 1 is a 19F-NMR spectrum of the acid diffusion inhibitor Q-4 obtained in Example 1-4. [Figure 9] 1 is a 1H-NMR spectrum of the acid diffusion inhibitor Q-5 obtained in Example 1-5. [Figure 10] 1 is a 19F-NMR spectrum of the acid diffusion inhibitor Q-5 obtained in Example 1-5. [Figure 11] 1 is a 1H-NMR spectrum of the acid diffusion inhibitor Q-6 obtained in Example 1-6. [Figure 12] 1 is a 19F-NMR spectrum of the acid diffusion inhibitor Q-6 obtained in Example 1-6. [Figure 13] 1 is a 1H-NMR spectrum of the acid diffusion inhibitor Q-7 obtained in Example 1-7. [Figure 14] 19F-NMR spectrum of the acid diffusion inhibitor Q-7 obtained in Example 1-7. [Figure 15] 1 is a 1H-NMR spectrum of the acid diffusion inhibitor Q-8 obtained in Example 1-8. [Figure 16] 1 is a 19F-NMR spectrum of the acid diffusion inhibitor Q-8 obtained in Example 1-8. [Figure 17] 1 is a 1H-NMR spectrum of the acid diffusion inhibitor Q-9 obtained in Example 1-9. [Figure 18] 19F-NMR spectrum of the acid diffusion inhibitor Q-9 obtained in Example 1-9. [Figure 19] 1 is a 1H-NMR spectrum of the acid diffusion inhibitor Q-10 obtained in Example 1-10. [Figure 20] 1 is a 19F-NMR spectrum of the acid diffusion inhibitor Q-10 obtained in Example 1-10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described in detail below. In the following description, some structures represented by chemical formulas may have asymmetric carbons and may have enantiomers or diastereomers, but in such cases, one formula will be used to represent these isomers. These isomers may be used alone or as a mixture.

[0013] [Onium salts] The onium salt of the present invention is represented by the following formula (1). [ka]

[0014] In formula (1), X is a sulfur atom or an iodine atom, and n is 1 when X is a sulfur atom, and is 0 when X is an iodine atom.

[0015] In formula (1), R 1 R is a hydrocarbyl group having 1 to 5 carbon atoms, which may contain a fluorine atom or an oxygen atom. The hydrocarbyl group having 1 to 5 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and an n-pentyl group. 1 is preferably a linear or branched hydrocarbyl group having 1 to 5 carbon atoms, more preferably a linear hydrocarbyl group having 1 to 5 carbon atoms. 1 is preferably not a tertiary hydrocarbyl group. The term "tertiary hydrocarbyl group" refers to a group obtained by removing hydrogen atoms from a tertiary carbon atom of a hydrocarbon. In addition, some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with fluorine atoms, and some of the -CH2- in the hydrocarbyl group may be substituted with ether bonds (-O-). 1 As the alkyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a 1-trifluoromethyl-2,2,2-trifluoroethyl group, and a 2-methoxyethyl group are preferable.

[0016] In formula (1), R 2 and R 3are each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. In addition, some or all of the hydrogen atoms in the hydrocarbyl group 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 -CH2- in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbyl group may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0017] R 2 and R 3 Specific examples of the hydrocarbyl group which may contain a heteroatom represented by the formula (I) include alkyl groups having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0] 2,6]Cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as decanyl group, adamantyl group, and adamantylmethyl group; alkenyl groups having 2 to 30 carbon atoms, such as vinyl group, allyl group, propenyl group, butenyl group, and hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 30 carbon atoms, such as cyclohexenyl group; phenyl group, 2-hydroxyphenyl group, 4-hydroxyphenyl group, 2-methoxyphenyl group, 3-methoxyphenyl group, 4-methoxyphenyl group, 4-fluorophenyl group, 4-iodophenyl group, 4-n-butylphenyl group, 4-tert-butylphenyl group, 4-tert-butoxyphenyl group, 4 aryl groups having 6 to 30 carbon atoms, such as a -trifluoromethylphenyl group, a 2,4-dimethylphenyl group, a 2,4,6-trimethylphenyl group, a 2,4,6-triisopropylphenyl group, a naphthyl group, a methylnaphthyl group, a methoxynaphthyl group, an ethoxynaphthyl group, an isopropoxynaphthyl group, a tert-butoxynaphthyl group, a dimethylnaphthyl group, a dihydroxynaphthyl group, or a dimethoxynaphthyl group; aralkyl groups having 7 to 30 carbon atoms, such as a benzyl group, a 1-phenylethyl group, or a 2-phenylethyl group; heteroaryl groups having 3 to 30 carbon atoms, such as a thienyl group; and groups obtained by combining these.

[0018] R 2 and R 3 As the substituent, a phenyl group which may be substituted is preferable. Examples of the substituent include a fluorine atom, an iodine atom, a trifluoromethyl group, a trifluoromethoxy group, a methyl group, a tert-butyl group, a hydroxy group, a methoxy group, a butoxy group, a methyl ... to An oxyethoxy group, a tert-butoxy group, a cyclohexylsulfonyl group, an acetyl group, and the like are preferred.

[0019] R 2 and R 3 may be bonded to each other to form a ring together with the X to which they are bonded. Examples of the ring include, but are not limited to, those shown below. [ka]

[0020] In formula (1), Ar is an arylene group having 6 to 14 carbon atoms, and is selected from the group consisting of a halogen atom, a hydroxy group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, and a aryl group having 2 to 1 carbon atoms which may contain a heteroatom. 0 may be substituted with a substituent selected from the hydrocarbylcarbonyloxy groups listed below.

[0021] Examples of the arylene group having 6 to 14 carbon atoms include a phenylene group, a naphthylene group, a phenanthrenediyl group, an anthracenediyl group, and a furandiyl group. Examples of the substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a trifluoromethyl group, a trifluoromethoxy group, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a hydroxy group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a hydroxy group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a hydroxy group, a methoxy group, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a methyl group, an ethyl group, a propyl group, an iso ... to Examples of such an aryl group include an oxyethoxy group, a tert-butoxy group, a 2,2,2-trifluoroethoxy group, a 2-hydroxyethoxy group, an acetyl group, a phenylcarbonyl group, an acetoxy group, a cyclohexylcarbonyloxy group, and a 3,3,3-trifluoro-2-trifluoromethyl-2-hydroxypropoxy group.

[0022] Also, R 2 and Ar may be bonded to each other to form a ring together with X to which they are bonded. In this case, the ring formed may be any of R 2 and R 3 Examples of the ring formed by bonding together include the same as those mentioned above.

[0023] The onium salt represented by formula (1) is preferably one represented by the following formula (2). [ka] (In the formula, R 1 , R 2 , R 3 , n, X and Z- is the same as above.)

[0024] In formula (2), R 4 R is a halogen atom, a hydroxy group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, or a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. 4 Examples of the substituent include the same ones as those exemplified in the description of Ar, and among them, a fluorine atom, an iodine atom, a trifluoromethyl group, a trifluoromethoxy group, a methyl group, an n-butyl group, a tert-butyl group, a hydroxy group, a methoxy group, a butoxy group, a methyl ... to Preferred are an oxyethoxy group, a tert-butoxy group, a 2,2,2-trifluoroethoxy group, an acetyl group, an acetoxy group, a cyclohexylcarbonyloxy group, a 3,3,3-trifluoro-2-trifluoromethyl-2-hydroxypropoxy group, and the like.

[0025] In formula (2), m is an integer of 0 to 4, and preferably an integer of 0 to 2.

[0026] Examples of the cation of the onium salt represented by formula (1) include, but are not limited to, those shown below. [ka]

[0027] [ka]

[0028] [ka]

[0029] [ka]

[0030]

change

[0031]

change

[0032]

change

[0033]

change

[0034]

change

[0035]

change

[0036]

change

[0037]

change

[0038]

change

[0039]

change

[0040] [ka]

[0041] In formula (1), Z - is a carboxylate anion, a sulfonamide anion, a sulfonimide anion, or a methide anion. - The anion is not particularly limited as long as it is one of these anions, but the pKa of the conjugate acid ZH is preferably -1.5 to 3.5. Examples of acids that satisfy the pKa range include carboxylic acids such as benzoic acid substituted with an electron-withdrawing group and carboxylic acids having an electron-withdrawing group (such as a halogen atom or a carbonyl group) at the α-position or β-position. Examples of sulfonimides include bis(alkylsulfonyl)imides, bis(arylsulfonyl)imides, alkylsulfonyl(arylsulfonyl)imides, trifluoromethylsulfonyl(alkylcarbonyl)imides, and bis(trifluoromethylcarbonyl)imides. Examples of methide acids include tris(alkylsulfonyl)methides. The pKa is calculated using ACD / ChemSketch by Advanced Chemistry Development (ACD / Labs). Z - However, when the conjugate acid is an anion with a pKa within the above range, it is possible to suppress acid diffusion without significantly impairing the sensitivity of the resist composition, leading to improvements in various lithography performances.

[0042] Z - Examples of such compounds include the following. [ka]

[0043] [ka]

[0044] [ka]

[0045] [ka]

[0046] [ka]

[0047] [ka]

[0048] [ka]

[0049] [ka]

[0050] [ka]

[0051] [ka]

[0052] Also, Z - In addition to the above, a carboxylate anion having at least one fluorine atom or trifluoromethyl group at the α-position or β-position of the carboxylate group is also preferred. As such a carboxylate anion, one represented by any one of the following formulas (Z-1) to (Z-5) is preferred. [ka]

[0053] In formula (Z-1), R 11 is a perfluoroalkyl group having 1 to 4 carbon atoms, and is preferably a trifluoromethyl group.

[0054] In formula (Z-2), R 12 and R 13 are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, provided that R 12 and R 13 At least one of the groups is a fluorine atom or a trifluoromethyl group. The remaining group is preferably a methyl group or a trifluoromethyl group.

[0055] In formula (Z-3), R 14 and R 15 are each independently a hydrocarbyl group having 1 to 15 carbon atoms which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. In addition, some or all of the hydrogen atoms in the hydrocarbyl group 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 -CH2- in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbyl group may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0056] R 14 and R 15 Specific examples of the hydrocarbyl group which may contain a heteroatom represented by the formula (I) include alkyl groups having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0] 2,6]Cyclic saturated hydrocarbyl groups having 3 to 15 carbon atoms, such as decanyl group, adamantyl group, and adamantylmethyl group; alkenyl groups having 2 to 15 carbon atoms, such as vinyl group, allyl group, propenyl group, butenyl group, and hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 15 carbon atoms, such as cyclohexenyl group; phenyl group, naphthyl group, thienyl group, 4-hydroxyphenyl group, 4-methoxyphenyl group, 3-methoxyphenyl group, 2-methoxyphenyl group, 4-ethoxyphenyl group, 4-tert-butoxyphenyl group, 3-tert-butoxyphenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, aryl groups having 6 to 15 carbon atoms, such as a 4-ethylphenyl group, a 4-tert-butylphenyl group, a 4-n-butylphenyl group, a 2,4-dimethylphenyl group, a 2,4,6-triisopropylphenyl group, a methylnaphthyl group, an ethylnaphthyl group, a methoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthyl group, an n-butoxynaphthyl group, a dimethylnaphthyl group, a diethylnaphthyl group, a dimethoxynaphthyl group, or a diethoxynaphthyl group; aralkyl groups having 7 to 15 carbon atoms, such as a benzyl group, a 1-phenylethyl group, or a 2-phenylethyl group; and groups obtained by combining these.

[0057] R 14 and R 15 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. Examples of the ring formed in this case include a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring.

[0058] R 14 is preferably a hydrogen atom. 15 is preferably a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain an oxygen atom, a fluorine atom or an iodine atom, and more preferably a hydrogen atom, an isopropyl group, a cyclohexyl group, an adamantyl group, or a phenyl group which may have a substituent.

[0059] In formulas (Z-3) to (Z-5), R 16 , R 17 and R 18are each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. In addition, some or all of the hydrogen atoms in the hydrocarbyl group 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 -CH2- in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbyl group may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like. Specific examples of the hydrocarbyl group which may contain a heteroatom include R 14 and R 15 Examples of the same as those given in the explanation of R 16 , R 17 and R 18 is preferably a hydrogen atom or a cyclic hydrocarbyl group having 3 to 30 carbon atoms which may contain a heteroatom.

[0060] In formulas (Z-3) and (Z-5), L 1 and L 2 are each independently a single bond, a carbonyl group, or a sulfonyl group, and are preferably a single bond or a carbonyl group.

[0061] Among the anions represented by any of formulas (Z-1) to (Z-5), those represented by the following formulas (Z-1a), (Z-2a), (Z-2b), (Z-3a), (Z-4a), (Z-5a) or (Z-5b) are particularly preferred. [ka] (In the formula, R 14 and R 15 is the same as above.)

[0062] In formulas (Z-3a), (Z-4a) and (Z-5a), R 16a , R17a and R 18a are each independently a cyclic hydrocarbyl group having 3 to 30 carbon atoms which may contain a heteroatom. Examples of the cyclic hydrocarbyl group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecanyl group, a norbornyl group, a tricyclo[5.2.1.0 2,6 ]alicyclic hydrocarbyl groups such as decanyl group, adamantyl group, cyclohexenyl group, and norbornenyl group; phenyl group, naphthyl group, thienyl group, 2-hydroxyphenyl group, 4-hydroxyphenyl group, 2-methoxyphenyl group, 3-methoxyphenyl group, 4-methoxyphenyl group, 4-fluorophenyl group, 4-iodophenyl group, 4-tert-butylphenyl group, 4-tert-butoxyphenyl group, 4-trifluoromethylphenyl group, 4-n-butylphenyl group, 2,4-dimethylphenyl group, 2,4, Examples of such groups include cyclic aromatic hydrocarbyl groups, such as 6-trimethylphenyl group, 2,4,6-triisopropylphenyl group, methylnaphthyl group, methoxynaphthyl group, ethoxynaphthyl group, isopropoxynaphthyl group, tert-butoxynaphthyl group, dimethylnaphthyl group, dihydroxynaphthyl group, and dimethoxynaphthyl group; spirocyclic hydrocarbyl groups, such as spiro[4,5]decanyl group; and groups in which some of the hydrogen atoms in these groups have been substituted with alkyl groups, alkenyl groups, aryl groups, aralkyl groups, alkoxy groups, or the like. In addition, some or all of the hydrogen atoms in the cyclic hydrocarbyl group 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 cyclic hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the cyclic hydrocarbyl group may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0063] R 16a , R 17a and R 18aAs the substituent, a cyclohexyl group which may have a substituent, an adamantyl group which may have a substituent, or a phenyl group which may have a substituent is preferable, and an adamantyl group which may have a substituent or a phenyl group which may have a substituent is preferable. As the substituent, a hydroxy group, a carboxy group, a fluorine atom or an iodine atom, a hydrocarbyl group having 1 to 14 carbon atoms which may contain a fluorine atom or an oxygen atom, a hydrocarbyloxy group having 1 to 14 carbon atoms which may contain a fluorine atom or an oxygen atom, a hydrocarbyloxyhydrocarbyloxy group having 2 to 14 carbon atoms which may contain a fluorine atom or an oxygen atom, a hydrocarbyloxycarbonyl group having 2 to 14 carbon atoms which may contain a fluorine atom or an oxygen atom, or a hydrocarbyloxycarbonyloxy group having 2 to 14 carbon atoms which may contain a fluorine atom or an oxygen atom is preferable.

[0064] Examples of the anion represented by any one of formulas (Z-1) to (Z-5) include, but are not limited to, those shown below. [ka]

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070]

change

[0071]

change

[0072]

change

[0073]

change

[0074]

change

[0075]

change

[0076]

change

[0077]

change

[0078]

change

[0079]

change

[0080]

change

[0081]

change

[0082]

change

[0083]

change

[0084]

change

[0085]

change

[0086]

change

[0087]

change

[0088]

change

[0089]

change

[0090]

change

[0091] [ka]

[0092] [ka]

[0093] Specific structures of the onium salt of the present invention include combinations of the specific anions and the specific cations described above, but are not limited thereto.

[0094] The onium salt of the present invention can be synthesized, for example, by the method shown in Scheme A below. [ka] (In the formula, R 1 , R 2 , R 3 , n, X and Z - is the same as above. + is a cation and Z' - is an anion.)

[0095] A carboxylate-type betaine compound (A) and an alcohol (B) are esterified to obtain a desired cation (C). The desired onium salt (1) can then be synthesized by salt exchange with a salt compound (D) having a desired anion. The first step of esterification can be carried out, for example, by converting the compound (A) into an acid chloride using oxalyl chloride or thionyl chloride, and then reacting it with an alcohol (B) under basic conditions. Examples of bases that can be used include triethylamine, pyridine, N,N-dimethylaminopyridine, and 2,6-lutidine. The second step of ion exchange can be easily achieved by a known method, and for example, JP-A-2007-145797 can be referred to.

[0096] The onium salt of the present invention can also be synthesized by the method shown in Scheme B below. [ka] (In the formula, R 1 , R 2 , R 3 , n, X, Z - , Z' - and M + is the same as above.)

[0097] The compound (A') containing a carboxyl group and an alcohol (B) are esterified to obtain the desired cation (C), which is then salt-exchanged with a salt compound (D) having the desired anion, to synthesize the desired onium salt (1). The esterification in the first step can be carried out, for example, as in Scheme A, by converting the compound (A') into an acid chloride using oxalyl chloride or thionyl chloride, and then reacting it with an alcohol (B) under basic conditions. Esterification can also be carried out under conditions using a condensing agent such as diisopropylcarbodiimide. The ion exchange in the second step can be easily achieved by a known method.

[0098] A resist composition using an onium salt represented by formula (1) exhibits fewer defects and is excellent in LWR, CDU and DOF. Although the details of the reason for this are unclear, it is presumed to be as follows.

[0099] Sulfonium cations and iodonium cations generate sulfide and iodobenzene as decomposition products after exposure. For example, it is known that photolysis of triphenylsulfonium cation generates diphenyl sulfide and [(2-phenyl)phenyl]phenyl sulfide. These photolysis products have poor solubility in alkaline developers, which causes development defects. The onium salt of the present invention has an alkali-decomposable group such as a chain alkyl ester or a fluorine atom-containing alkyl ester as a partial structure of the cation. Since the decomposition products after exposure also have the alkali-decomposable group, when the decomposition products are developed in an alkaline state, the ester structure is decomposed and the exposure decomposition products become soluble in an alkaline state, which leads to a reduction in defects and an improvement in the patterning ability, and is considered to improve various lithography performances. The ester structure is preferably a linear structure in order not to reduce the alkali decomposability. If a quaternary carbon atom derived from a tert-butyl group or the like is present in the vicinity of the ester, the alkali decomposability may be impaired. In addition, the onium salt of the present invention is decomposed by an alkali to generate a carboxyl group on the cation side. When the ester bond type is reversed, a phenolic hydroxy group is generated on the cation side, but since the phenolic hydroxy group has a lower solubility in alkali than the carboxy group, a sufficient improvement effect cannot be obtained.

[0100] In addition, using an alkali-decomposable cation as the cation of the acid diffusion inhibitor leads to an improvement in lithography performance. Although the above-mentioned improvement effect can be expected by introducing an alkali-decomposable group into the cation of the photoacid generator, the lithography performance is improved by combining it with the anion of a weak acid used in the acid diffusion inhibitor. The reason for this is unclear, but it can be considered as follows. In general, the anion of a weak acid used in an acid diffusion inhibitor is more hydrophilic than the anion of a strong acid such as fluorosulfonic acid used in a photoacid generator. The onium salt of the present invention is a combination of a cation that improves solubility in an alkaline developer and a hydrophilic anion (i.e., highly soluble in an alkaline developer), so it is more soluble in an alkaline developer than an anion of a strong acid that has low solubility in an alkaline developer, and it is considered that the defect reduction and pattern removal are improved.

[0101] In addition, as a cation having an alkali-decomposable group, a structure in which a partial structure that reacts with an alkali developer is bonded to a cation via various linking groups such as an alkoxyacetate structure is also considered. Acid diffusion inhibitor The onium salt of the present invention has excellent lithography performance. This can be presumed as follows. Since the onium salt of the present invention has a carboxy group directly bonded to the benzene ring of the cation, the acidity of the generated carboxylic acid is high. In other words, the decomposition reaction rate of the ester moiety by alkali is higher than that of a non-directly bonded cation, so that decomposition can be carried out efficiently even in a short reaction time during development, which is advantageous.

[0102] In addition, the onium salt of the present invention improves lithography performance by using it together with a base polymer having a photoacid generator component in the polymer. A polymer having a photoacid generator component in the main chain has excellent hydrophilicity compared to a polymer not having a photoacid generator in the main chain. Although the details are unclear, it is thought that the combination of a hydrophilic polymer and a hydrophilic acid diffusion inhibitor can more efficiently reduce defects and improve pattern transparency.

[0103] [Chemically amplified resist composition] The chemically amplified resist composition of the present invention comprises (A) a base polymer including a repeating unit whose solubility in a developer changes upon the action of an acid; (B) a photoacid generator, (C-1) an acid diffusion inhibitor comprising the onium salt of the present invention, and (D) Organic solvent Contains as an essential ingredient, and as necessary, (C-2) an acid diffusion inhibitor other than the onium salt of the present invention, (E) a surfactant, and (F) Other Ingredients may include:

[0104] or (A') a base polymer including a repeating unit having a function of changing solubility in a developer by the action of an acid and generating an acid upon exposure; (C-1) an acid diffusion inhibitor comprising the onium salt of the present invention, and (D) Organic solvent Contains as an essential ingredient, and as necessary, (B) a photoacid generator, (C-2) an acid diffusion inhibitor other than the onium salt of the present invention, (E) a surfactant, and (F) Other Ingredients may include:

[0105] [(A) Base polymer] The base polymer of component (A) is preferably a polymer containing a repeating unit represented by the following formula (a) (hereinafter also referred to as repeating unit a) or a repeating unit represented by the following formula (b) (hereinafter also referred to as repeating unit b). [ka]

[0106] In formulas (a) and (b), R A are each independently a hydrogen atom or a methyl group. A is a single bond, a phenylene group, a naphthylene group, or (main chain)-C(=O)-OX A1- X A1 X is a hydrocarbylene group having 1 to 15 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring. B is a single bond or an ester bond. 1 and A.L. 2 are each independently an acid labile group.

[0107] acid labile group AL 1 and A.L. 2 Examples of the acid labile group include, but are not limited to, a tertiary hydrocarbyl group having 4 to 20 carbon atoms, a trihydrocarbylsilyl group in which each hydrocarbyl group is an alkyl group having 1 to 6 carbon atoms, and an oxoalkyl group having 4 to 20 carbon atoms. For a detailed explanation of the specific structures of these acid labile groups, see paragraphs

[0066] to

[0100] of JP2015-214634A.

[0108] acid labile group AL 1 and A.L. 2 is preferably a group represented by the following formula (L1). [ka]

[0109] In formula (L1), R 21 represents a hydrocarbyl group having 1 to 7 carbon atoms, in which -CH2- may be replaced by -O-. a is 1 or 2. The dashed line represents a bond.

[0110] acid labile group AL 1 and A.L. 2 As the group, the following groups are particularly preferred. [ka] (In the formula, the dashed lines represent bonds.)

[0111] X in formula (a) ASpecific examples of structures in which the above has been changed include those described in paragraph

[0015] of JP2014-225005A, but the following structures are preferred. [ka] (In the formula, R A and A.L. 1 is the same as above.)

[0112] Examples of the repeating unit a include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0113] [ka]

[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] Examples of the repeating unit b include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0118] [ka]

[0119] [ka]

[0120] [ka]

[0121] The above specific examples are X A and X B In the above, X is a single bond, but even when X is a bond other than a single bond, it can be combined with a similar acid labile group. A Specific examples of when X is other than a single bond are as described above. B Specific examples of the ester bond include those in which the single bond between the main chain and the benzene ring in the above specific examples is replaced with an ester bond.

[0122] The base polymer preferably contains a repeating unit represented by the following formula (c) (hereinafter also referred to as repeating unit c). [ka]

[0123] In formula (c), R A is a hydrogen atom or a methyl group. A is a single bond or an ester bond.

[0124] In formula (c), R 22is a fluorine atom, an iodine atom, a carboxy group, a formyl group, a formyloxy group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. The hydrocarbyl group and the hydrocarbyloxy group, the hydrocarbylcarbonyl group, the hydrocarbylcarbonyloxy group, and the hydrocarbyloxycarbonyloxy group may be saturated or unsaturated, and may be linear, branched, or cyclic.

[0125] Examples of the hydrocarbyl group having 1 to 10 carbon atoms include alkyl groups having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, and an n-decyl group; cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms, such as a cyclopentyl group, a cyclohexyl group, an adamantyl group, and a norbornyl group; alkenyl groups having 2 to 10 carbon atoms, such as a vinyl group and an allyl group; aryl groups having 6 to 10 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, a propylphenyl group, an isopropylphenyl group, a butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, and a tert-butylphenyl group; aralkyl groups having 7 to 10 carbon atoms, such as a benzyl group; and groups obtained by combining these groups.

[0126] Examples of the hydrocarbyloxy group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, a tert-butoxy group, a phenoxy group, and a 2-methoxyethoxy group. Examples of the hydrocarbylcarbonyl group having 2 to 10 carbon atoms include an acetyl group, an ethylcarbonyl group, a hexylcarbonyl group, and a phenylcarbonyl group. Examples of the hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms include an acetoxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, a pentylcarbonyloxy group, a hexylcarbonyloxy group, and a heptylcarbonyloxy group. Examples of the hydrocarbyloxycarbonyloxy group having 2 to 10 carbon atoms include a methoxycarbonyloxy group, an ethoxycarbonyloxy group, a hexyloxycarbonyloxy group, and a phenyloxycarbonyloxy group.

[0127] In addition, some or all of the hydrogen atoms in the hydrocarbyl group 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 hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, so that the hydrocarbyl group may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a carboxy group, an ether bond, an ester bond, a lactone ring, etc. Examples of such substituted groups include alkoxyalkoxy groups such as a methoxymethoxy group, an ethoxymethoxy group, a 1-ethoxyethoxy group, and a 1-methoxy-2-methylpropyloxy group; alkoxyalkylcarbonyloxy groups such as a methoxymethylcarbonyloxy group and a (2-methoxyethoxy)methylcarbonyloxy group; and alkoxycarbonyloxy groups such as a methoxycarbonyloxy group, an ethoxycarbonyloxy group, and a tert-butoxycarbonyloxy group.

[0128] R 22 is preferably a fluorine atom, an iodine atom, a methyl group, an acetyl group or a methoxy group.

[0129] In formula (c), b and c are integers satisfying 1≦b≦5, 0≦c≦4, and 1≦b+c≦5. b is preferably 1, 2, or 3, and c is preferably 0, 1, or 2.

[0130] Repeating unit c improves adhesion to the substrate and underlying film. In addition, since it has a highly acidic phenolic hydroxyl group, it promotes the action of the acid generated by exposure to light, contributing to high sensitivity, and in EUV lithography, it is a source of protons for the acid generated by exposure to light, which is expected to improve sensitivity.

[0131] Examples of the repeating unit c include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0132] [ka]

[0133] [ka]

[0134] [ka]

[0135] Among these, the repeating unit c is preferably the one shown below. In the following formula, R A is the same as above. [ka]

[0136] The base polymer may contain a repeating unit represented by any one of the following formulas (d1), (d2), (d3) and (d4) (hereinafter also referred to as repeating units d1, d2, d3 and d4). [ka]

[0137] In formulas (d1) to (d4), R A R is each independently a hydrogen atom or a methyl group. f1 , R f2 and R f3 are each independently a hydrogen atom or a trifluoromethyl group. A and Z B Z each independently represents a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. C is a single bond, -Z C1 -, -OZ C1 - or -C(=O)-OZ C1 -It is. C1 is a phenylene group, which may be substituted with a hydroxy group, a fluorine atom, an iodine atom, a trifluoromethyl group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, or a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. D is a single bond, a phenylene group, -OZ D1 -, -C(=O)-OZ D1 - or -C(=O)-NH-Z D1 -It is. D1 is a hydrocarbylene group which may contain a heteroatom.

[0138] Z A and Z BThe hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups having 1 to 20 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, butane-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, and 2,2-dimethylpropane-1,3-diyl group; cyclopentanediyl group, cyclohexanediyl group, and norbornanediyl group. cyclic saturated hydrocarbylene groups such as ethene-1,2-diyl group, 1-propene-1,3-diyl group, 2-butene-1,4-diyl group, 1-methyl-1-butene-1,4-diyl group, etc.; cyclic unsaturated aliphatic hydrocarbylene groups such as 2-cyclohexene-1,4-diyl group, etc.; aromatic hydrocarbylene groups such as phenylene group, naphthylene group, phenylene group substituted with an alkyl group having 1 to 10 carbon atoms, naphthylene group substituted with an alkyl group having 1 to 10 carbon atoms, etc.; and groups obtained by combining these. In addition, some or all of the hydrogen atoms in the hydrocarbylene group 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 hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the formation of a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxyl group, , S It may contain an ano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like. A and Z B is preferably a single bond, an adamantanediyl group, a phenylene group or a substituted phenylene group.

[0139] Z D1The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those represented by the formula (I). A and Z B Examples of the hydrocarbylene group represented by the formula Z include the same as those exemplified above. D contains a phenyl group, and the phenyl group is S in the formula + A structure in which the

[0140] In formulas (d1) to (d4), R 31 ~R 41 is a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. In addition, some or all of the hydrogen atoms in the hydrocarbyl group 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 -CH2- in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbyl group may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like. In addition, R 31 and R 32 , R 34 and R 35 , R 37 and R 38 or R 40 and R 41 may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0141] R 31 ~R 41Specific examples of the hydrocarbyl group which may contain a heteroatom represented by the formula (I) include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0] 2,6 ]Cyclic saturated hydrocarbyl groups such as decanyl, adamantyl, and adamantylmethyl; alkenyl groups such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated aliphatic hydrocarbyl groups such as cyclohexenyl; phenyl, naphthyl, 4-hydroxyphenyl, 2-hydroxyphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 4-tert-butoxyphenyl, 3-tert-butoxyphenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 4-n-butylphenyl, 4-n-butoxyphenyl, 4-fluorophenyl, 3-fluorophenyl, 4-iodophenyl, 4-fluorophenyl, aryl groups having 6 to 30 carbon atoms, such as a fluoro-3-hydroxyphenyl group, a 3-fluoro-4-hydroxyphenyl group, a 4-fluoro-3-tert-butoxyphenyl group, a 3-fluoro-4-tert-butoxyphenyl group, a 2,4-dimethylphenyl group, a 2,6-dimethylphenyl group, a 2,4,6-trimethylphenyl group, a 2,4,6-triisopropylphenyl group, a methylnaphthyl group, an ethylnaphthyl group, a methoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthyl group, an n-butoxynaphthyl group, a dimethylnaphthyl group, a diethylnaphthyl group, a dimethoxynaphthyl group, or a diethoxynaphthyl group; aralkyl groups, such as a benzyl group, a 1-phenylethyl group, or a 2-phenylethyl group; heteroaryl groups having 3 to 30 carbon atoms, such as a thienyl group; and groups obtained by combining these.

[0142] In formulas (d1) to (d4), R 31 ~R 41 contains a phenyl group, and the phenyl group is S in the formula + A structure in which the

[0143] In formula (d1), k 1 is 0 or 1, but Z A When is a single bond, it is 0. In formula (d2), k 2 is 0 or 1, but Z B is 0 when it is a single bond.

[0144] In formula (d4), Xa - is a non-nucleophilic counter ion. The non-nucleophilic counter ion is not particularly limited, but examples thereof include halide ions such as chloride ion and bromide ion; fluoroalkylsulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion, and nonafluorobutanesulfonate ion; arylsulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, and 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as mesylate ion and butanesulfonate ion; imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, and bis(perfluorobutylsulfonyl)imide ion; methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion, and the like, and is preferably an anion represented by the following formula (d4-1) or (d4-2). [ka]

[0145] In formulas (d4-1) and (d4-2), R 51 and R 52 R is each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. f4is a hydrogen atom or a trifluoromethyl group.

[0146] Examples of the anion represented by formula (d4-1) include, but are not limited to, those described in paragraphs

[0108] to

[0109] of JP 2014-225005 A, those described in paragraphs

[0123] to

[0129] of JP 2016-040598 A, and those represented by the following formula. f4 is the same as above. [ka]

[0147] [ka]

[0148] [ka]

[0149] Specific examples of the anion moiety represented by formula (d4-2) include those described in paragraphs

[0080] to

[0081] of JP2010-215608A and those represented by the following formula, but are not limited thereto. In the following formula, Ac is an acetyl group. [ka]

[0150] For repeat unit d1, R f1 When R is a hydrogen atom, JP 2010-116550 A is described in detail. f1 When is a trifluoromethyl group, JP2010-77404A provides detailed information. Specific examples of the anion in the repeating unit d1 include those described in these publications and those described in paragraphs

[0021] to

[0026] of JP2014-177407A.

[0151] For repeat unit d2, Rf2 and R f3 In the case where R is a trifluoromethyl group, specific examples of the anion in the repeating unit d2 are described in JP 2017-031377 A. f1 )CF2SO3 - -C(CF3)2CH2SO3 - or -CH2CH2SO3 - Examples of structures include those in which

[0152] Preferred examples of the anion of the repeating units d1 to d3 include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0153] Specific examples of the sulfonium cation in the repeating units d1 to d3 include, but are not limited to, those shown below: In the following formula, Me is a methyl group, and tBu is a tert-butyl group. [ka]

[0154] [ka]

[0155] [ka]

[0156] [ka]

[0157] [ka]

[0158] [ka]

[0159] Preferred examples of the cation of the repeating unit d4 include, but are not limited to, those shown below. A is the same as above. [ka]

[0160] The sulfonium cation in the repeating units d1 to d3 is preferably a cation represented by the following formula (M-1) or (M-2). [ka]

[0161] In formulas (M-1) and (M-2), R M1 , R M2 and R M3 each independently represents a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 15 carbon atoms which may contain a heteroatom. each independently represents an integer of 0 to 4. In formula (M-2), L represents a single bond, an ether bond, or a carbonyl bond.

[0162] Examples of the sulfonium cation represented by formula (M-1) or (M-2) include, but are not limited to, those shown below, in which Me is a methyl group and tBu is a tert-butyl group. [ka]

[0163] The repeating units d1 to d4 function as a photoacid generator. When a base polymer containing the repeating units d1, d2, d3, or d4 is used, the blending of an additive-type photoacid generator described below may be omitted. Among the repeating units d1 to d4, the repeating unit d1 is preferred.

[0164] The base polymer may further contain, as another adhesive group, a repeating unit containing a hydroxy group other than a phenolic hydroxy group, a lactone ring, a sultone ring, an ether bond, an ester bond, an amide group, an imide group, a carbonyl group, a sulfinyl group, a sulfonyl group, a cyano group, or a carboxy group (hereinafter also referred to as repeating unit e).

[0165] Examples of the repeating unit e include, but are not limited to, those shown below. In the following formula, R A is the same as above, and Me is a methyl group. [ka]

[0166] [ka]

[0167] [ka]

[0168] [ka]

[0169] In addition to the above, examples of the repeating unit e include those described in paragraphs

[0045] to

[0053] of JP2014-225005A.

[0170] Among these, the repeating unit e is preferably one having a hydroxy group or a lactone ring, for example, the following is preferred. Ais the same as above, and Me is a methyl group. [ka]

[0171] The base polymer may further include a repeating unit having a structure in which a hydroxyl group is protected by an acid labile group as another repeating unit. Such a repeating unit is not particularly limited as long as it has one or more structures in which a hydroxyl group is protected by an acid labile group, and the protecting group is decomposed by the action of an acid to generate a hydroxyl group, but specific examples thereof include those described in paragraphs

[0055] to

[0065] of JP2014-225005A and those described in paragraphs

[0110] to

[0115] of JP2015-214634A.

[0172] The base polymer may further contain other repeating units other than those described above. Examples of the other repeating units include repeating units having an oxirane ring or an oxetane ring. By including a repeating unit having an oxirane ring or an oxetane ring, the exposed portion is crosslinked, improving the residual film properties and etching resistance of the exposed portion. Examples of the repeating unit having an oxirane ring or an oxetane ring include those described in paragraphs

[0120] to

[0122] of JP 2015-214634 A.

[0173] Other repeating units include substituted acrylic esters such as methyl crotonate, dimethyl maleate, and dimethyl itaconate; unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid; norbornene, norbornene derivatives, tetracyclo[6.2.1.1 3,6 .0 2,7 ] Cyclic olefins such as dodecene derivatives; unsaturated acid anhydrides such as itaconic anhydride; aromatics such as styrene, tert-butylstyrene, vinylnaphthalene, acetoxystyrene, methoxystyrene, acenaphthylene, phenyl methacrylate, benzyl methacrylate, and phenyl vinyl ether; and repeating units obtained from other monomers.

[0174] The weight average molecular weight (Mw) of the base polymer is preferably 1,000 to 500,000, more preferably 3,000 to 100,000, and further preferably 4,000 to 20,000. When Mw is within the above range, the etching resistance is not extremely decreased, and the difference in dissolution rate before and after exposure is ensured, so that the resolution is good. In the present invention, Mw is a value measured in terms of polystyrene by gel permeation chromatography (GPC). The dispersity (Mw / Mn) is preferably 1.20 to 2.50, and more preferably 1.30 to 2.00.

[0175] The base polymer can be synthesized, for example, by polymerizing one or more desired monomers among monomers that provide various repeating units in an organic solvent with the addition of a radical polymerization initiator. Such a polymerization method is described in detail in paragraphs

[0134] to

[0137] of JP 2015-214634 A. In addition, the acid labile group introduced into the monomer may be used as it is, or may be protected or partially protected after polymerization.

[0176] In the base polymer, the preferred content of each repeating unit can be, for example, within the ranges (mol %) shown below, but is not limited thereto. (I) One or more repeating units selected from the repeating units a and b are contained in an amount of preferably 10 to 70 mol %, more preferably 20 to 65 mol %, and even more preferably 30 to 60 mol %, and optionally (II) One or more repeating units c are preferably contained in an amount of 0 to 90 mol %, more preferably 15 to 80 mol %, and even more preferably 30 to 60 mol %, and optionally (III) One or more repeating units selected from the repeating units d1 to d4 are preferably contained in an amount of 0 to 30 mol %, more preferably 0 to 20 mol %, and even more preferably 5 to 20 mol %, and optionally (IV) One or more types selected from the repeating unit e and other repeating units may be contained in an amount of preferably 0 to 80 mol %, more preferably 0 to 70 mol %, and even more preferably 0 to 50 mol %.

[0177] The base polymer of component (A) may be used alone or in combination with two or more different polymers having different composition ratios, Mw and / or Mw / Mn. The base polymer of component (A) may contain a hydrogenated ring-opening metathesis polymer in addition to the above-mentioned polymer. As the hydrogenated ring-opening metathesis polymer, those described in JP-A-2003-66612 can be used.

[0178] [(B) Photoacid generator] When the base polymer does not contain the repeating units d1 to d4, the chemically amplified resist composition of the present invention contains (B) a photoacid generator (hereinafter also referred to as an additive-type photoacid generator) as an essential component. Note that even when the base polymer contains at least one selected from the repeating units d1 to d4, the additive-type photoacid generator may be contained.

[0179] The additive-type photoacid generator is not particularly limited as long as it is a compound that generates an acid when irradiated with high-energy rays. Suitable photoacid generators include photoacid generators such as sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxydicarboximide, O-arylsulfonyloximes, and O-alkylsulfonyloximes. Specifically, for example, the compounds described in paragraphs

[0102] to

[0113] of JP 2007-145797 A, the compounds described in paragraphs

[0122] to

[0142] of JP 2008-111103 A, the compounds described in paragraphs

[0081] to

[0092] of JP 2014-001259 A, the compounds described in JP 2012-41320 A, the compounds described in JP 2012-153644 A, the compounds described in JP 2012-106986 A, the compounds described in JP 2016-018007 A, etc. can be mentioned. The partially fluorinated sulfonic acid generating photoacid generators described in these publications have moderate strength and diffusion length of the generated acid, particularly in ArF lithography, and are preferably used.

[0180] Preferred examples of the photoacid generator of the component (B) include sulfonium salts represented by the following formula (3A) and iodonium salts represented by the following formula (3B). [ka]

[0181] In formulas (3A) and (3B), R 101 ~R 105 are each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. As the hydrocarbyl group, R 31 ~R 41 Examples of the above are the same as those given in the explanation of R. 101 and R 102 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, R 104 and R 105 may be bonded to each other to form a ring together with the iodine atom to which they are attached.

[0182] The cation of the sulfonium salt represented by formula (3A) is described in detail in paragraphs

[0082] to

[0085] of JP-A-2014-001259. Specific examples of the sulfonium cation include the cations described in paragraphs

[0027] to

[0033] of JP-A-2007-145797, the cations described in paragraph

[0059] of JP-A-2010-113209, the cations described in JP-A-2012-41320, the cations described in JP-A-2012-153644 and JP-A-2012-106986, and the cations exemplified as the cations in formulae (d1) to (d3).

[0183] The cation of the sulfonium salt represented by formula (3A) is preferably, but not limited to, the following: In the following formula, Me is a methyl group, and tBu is a tert-butyl group. [ka]

[0184] As the cation of the sulfonium salt represented by formula (3A), particularly preferred is a triphenylsulfonium cation, an S-phenyldibenzothiophenium cation, a (4-tert-butylphenyl)diphenylsulfonium cation, a (4-fluorophenyl)diphenylsulfonium cation, or a (4-hydroxyphenyl)diphenylsulfonium cation.

[0185] The cation of the iodonium salt represented by formula (3B) is preferably, but not limited to, the following: In the following formula, Me is a methyl group, and tBu is a tert-butyl group. [ka]

[0186] As the cation of the iodonium salt represented by the formula (3B), a diphenyliodonium cation or a di-tert-butylphenyliodonium cation is particularly preferred.

[0187] In formulas (3A) and (3B), Xb - is an anion represented by the following formula (3C) or (3D). [ka]

[0188] In formula (3C), R fa is a fluorine atom, a perfluoroalkyl group having 1 to 4 carbon atoms, or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom.

[0189] The anion represented by formula (3C) is preferably a trifluoromethanesulfonate anion, a nonafluorobutanesulfonate anion, or an anion represented by the following formula (3C'). [ka]

[0190] In formula (3C'), R HF is a hydrogen atom or a trifluoromethyl group.

[0191] In formula (3C'), R 111 is a hydrocarbyl group having 1 to 35 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclooctyl, norbornyl, and tricyclo[5.2.1.0]. 2,6 ]Cyclic saturated hydrocarbyl groups having 3 to 35 carbon atoms, such as decanyl group, adamantyl group, etc.; alkenyl groups, such as vinyl group, allyl group, propenyl group, butenyl group, hexenyl group, etc.; cyclic unsaturated aliphatic hydrocarbyl groups, such as cyclohexenyl group, etc.; aryl groups, such as phenyl group, naphthyl group, thienyl group, etc.; aralkyl groups, such as benzyl group, 1-phenylethyl group, 2-phenylethyl group, etc.; and groups obtained by combining these groups. In addition, some or all of the hydrogen atoms in the hydrocarbyl group 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 hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0192] The anion represented by formula (3C') is described in detail in JP2007-145797A, JP2008-106045A, JP2009-007327A, JP2009-258695A, and JP2012-181306A. Specific examples of the anion represented by formula (3C') include the anions described in these publications.

[0193] In formula (3D), R fb is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. The anion represented by formula (3D) is described in detail in JP 2010-215608 A and JP 2014-133723 A. Specific examples of the anion represented by formula (3D) include the anions described in these publications. The anion represented by formula (3D) does not have a fluorine atom at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave acid labile groups in a resist polymer. Therefore, it can be used as a photoacid generator.

[0194] Xb - The anion represented by the formula (I) is preferably, but not limited to, the following: HF is a hydrogen atom or a trifluoromethyl group. [ka]

[0195] [ka]

[0196] Specific structures of the photoacid generator represented by formula (3A) or (3B) include any combination of the specific anions and the specific cations described above, but are not limited thereto.

[0197] Other preferred examples of the photoacid generator (B) include the compounds represented by the following formula (4). [ka]

[0198] In formula (4), R 201 and R 202 R is each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 201 , R 202 and R 203 Any two of may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0199] R 201 and R 202 The hydrocarbyl group represented by the formula (3C') may be saturated or unsaturated and may be linear, branched, or cyclic. 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0200] R 203The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups having 1 to 30 carbon atoms, such as a methanediyl group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, a dodecane-1,12-diyl group, a tridecane-1,13-diyl group, and a tetradecane-1,14-diyl group; cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as a cyclopentanediyl group, a cyclohexanediyl group, a norbornanediyl group, and an adamantanediyl group. arylene groups such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group, an isobutylphenylene group, a sec-butylphenylene group, a tert-butylphenylene group, a dimethylphenylene group, a diethylphenylene group, a naphthylene group, a methylnaphthylene group, an ethylnaphthylene group, an n-propylnaphthylene group, an isopropylnaphthylene group, an n-butylnaphthylene group, an isobutylnaphthylene group, a sec-butylnaphthylene group, a tert-butylnaphthylene group, a dimethylnaphthylene group, or a diethylnaphthylene group; and groups obtained by combining these. In addition, some or all of the hydrogen atoms in the hydrocarbylene group 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 hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbylene group may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0201] In formula (4), L Ais a single bond, an ether bond, an ester bond, or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom, and -CH 2 - may be replaced by -O- or -C(=O)-. Note that -CH- in the hydrocarbylene group is a carbon atom of the benzene ring in formula (4) and / or R 203 It may be one that binds to L A The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 203 Examples of the examples are similar to those given in the description of .

[0202] In formula (4), X 1 , X 2 , X 3 and X 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that at least one of them is a fluorine atom or a trifluoromethyl group.

[0203] As the compound represented by formula (4), the compound represented by the following formula (4') is particularly preferable. [ka]

[0204] In formula (4'), R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, and some or all of the hydrogen atoms in the hydrocarbyl group 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 -CH2- in the hydrocarbyl group may be substituted with -O- or -C(=O)-. The -CH2- in the hydrocarbyl group may be bonded to a carbon atom of a benzene ring in formula (4'). R 301 , R 302and R 303 The hydrocarbyl group represented by the formula (3C') may be saturated or unsaturated and may be linear, branched, or cyclic. 111 Examples of the hydrocarbyl group represented by the formula: x and y each independently represent an integer of 0 to 5, and z represents an integer of 0 to 4.

[0205] Photoacid generators represented by formula (4) or (4') are described in detail in JP2011-16746A. Specific examples thereof include the sulfonium salts described in the above publication and the sulfonium salts described in paragraphs

[0149] to

[0150] of JP2015-214634A.

[0206] Examples of photoacid generators represented by formula (4) include, but are not limited to, those shown below. In the following formula, R HF is the same as above, Me is a methyl group, and tBu is a tert-butyl group. [ka]

[0207] [ka]

[0208] The content of the (B) component is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass, and even more preferably 4 to 20 parts by mass, based on 100 parts by mass of the (A) base polymer. If the content is within the above range, there is no risk of degradation of resolution or problems with foreign matter occurring after resist development or during peeling. The (B) component photoacid generator may be used alone or in combination of two or more types.

[0209] [(C) Acid diffusion inhibitor] The chemically amplified resist composition of the present invention contains an acid diffusion inhibitor (quencher) as component (C). Component (C) contains an onium salt represented by formula (1) as essential component (C-1), but may contain an acid diffusion inhibitor (C-2) other than the onium salt represented by formula (1). In the present invention, the acid diffusion inhibitor refers to a compound that can suppress the diffusion rate when the acid generated by the photoacid generator diffuses into the resist film.

[0210] Examples of the acid diffusion inhibitor (C-2) include amine compounds and onium salts of weak acids such as sulfonic acids or carboxylic acids not fluorinated at the α-position.

[0211] The amine compound may be a primary, secondary or tertiary amine compound, particularly an amine compound having any of a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group and a sulfonate ester bond. In addition, a primary or secondary amine compound protected with a carbamate group may be used as an acid diffusion inhibitor. Such a protected amine compound is effective when the resist composition contains a component that is unstable to base. Examples of such an acid diffusion inhibitor include, but are not limited to, the compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A, the compounds described in Japanese Patent No. 3790649 A, and the following. [ka]

[0212] [ka]

[0213] Examples of the onium salt-based acid diffusion inhibitor of a sulfonic acid or carboxylic acid not fluorinated at the α-position include onium salts represented by the following formula (5A) or (5B). [ka]

[0214] In formula (5A), R q1 is a hydrogen atom, a methoxy group, or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, except for those in which the hydrogen atom on the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group.

[0215] R q1 The hydrocarbyl group having 1 to 40 carbon atoms and optionally containing a heteroatom represented by the formula (1) may be saturated or unsaturated, and may be linear, branched, or cyclic. In addition, some or all of the hydrogen atoms in the hydrocarbyl group 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 -CH2- in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbyl group may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0216] R q1 Specific examples of the hydrocarbyl group which may contain a heteroatom represented by the formula (I) include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a tert-pentyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, 2-ethylhexyl group, Alkyl groups having 1 to 40 carbon atoms, such as n-nonyl and n-decyl groups; cyclopentyl and cyclohexyl groups , S Cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6] Cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as decanyl group, adamantyl group, and adamantylmethyl group; alkenyl groups having 2 to 40 carbon atoms, such as vinyl group, allyl group, propenyl group, butenyl group, and hexenyl group; cyclic unsaturated hydrocarbyl groups having 3 to 40 carbon atoms, such as cyclohexenyl group; hydroxyphenyl groups, such as phenyl group, naphthyl group, and 4-hydroxyphenyl group; alkoxyphenyl groups, such as 4-methoxyphenyl group, 3-methoxyphenyl group, 2-methoxyphenyl group, 4-ethoxyphenyl group, 4-tert-butoxyphenyl group, and 3-tert-butoxyphenyl group; aryl groups, such as 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-n-butylphenyl group, 2,4-dimethylphenyl group, and 2,4,6-triisopropylphenyl group. aryl groups having 6 to 40 carbon atoms, such as alkylphenyl groups, methylnaphthyl groups, and ethylnaphthyl groups; alkoxynaphthyl groups, such as methoxynaphthyl groups, ethoxynaphthyl groups, n-propoxynaphthyl groups, and n-butoxynaphthyl groups; dialkylnaphthyl groups, such as dimethylnaphthyl groups and diethylnaphthyl groups, and dialkoxynaphthyl groups, such as dimethoxynaphthyl groups and diethoxynaphthyl groups; aralkyl groups having 7 to 40 carbon atoms, such as benzyl groups, 1-phenylethyl groups, and 2-phenylethyl groups; heteroaryl groups having 3 to 40 carbon atoms, such as thienyl groups; aryloxoalkyl groups having 8 to 40 carbon atoms, such as 2-aryl-2-oxoethyl groups, such as 2-phenyl-2-oxoethyl groups, 2-(1-naphthyl)-2-oxoethyl groups, and 2-(2-naphthyl)-2-oxoethyl groups; and groups obtained by combining these.

[0217] In formula (5B), R q2 is a hydrogen atom, a hydroxyl group, or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom.

[0218] R q2 The hydrocarbyl group having 1 to 40 carbon atoms and optionally containing a heteroatom, represented by the following formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R q1and groups obtained by removing a carboxy group from a carboxylate anion represented by formulae (Z-1) to (Z-5).

[0219] The sulfonic acid onium salt represented by formula (5A) and the carboxylic acid onium salt represented by formula (5B) are described in detail in JP-A-2008-158339 and JP-A-2010-155824. Specific examples of these compounds are described in these publications.

[0220] Examples of the anion of the onium sulfonate represented by formula (5A) include, but are not limited to, those shown below. [ka]

[0221] Examples of the anion of the carboxylate onium salt represented by formula (5B) include, but are not limited to, those shown below. [ka]

[0222] In formulas (5A) and (5B), Mq + is an onium cation. The onium cation is preferably one represented by the following formula (5C), (5D) or (5E). [ka]

[0223] In formulas (5C) to (5E), R 401 ~R 409 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. 401 and R 402 , R 404 and R 405 or R 406 and R 407may be bonded to each other to form a ring together with the sulfur atom, iodine atom or nitrogen atom to which they are bonded.

[0224] Examples of the cation represented by formula (5C) include the same as those exemplified as the cations in formulas (d1) to (d3). Examples of the cation represented by formula (5D) include the same as those exemplified as the cations of the iodonium salt represented by formula (3B). Examples of the cation represented by formula (5E) include tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, trimethylbenzyl cation, trimethylphenyl cation, etc.

[0225] Mq + As the onium cation represented by the formula, the following is particularly preferred: In the following formula, Me is a methyl group, and tBu is a tert-butyl group. [ka]

[0226] Specific examples of the sulfonic acid onium salt represented by formula (5A) and the carboxylic acid onium salt represented by formula (5B) include any combination of the above-mentioned anions and cations. These onium salts can be easily prepared by ion exchange reaction using a known organic chemical method. For the ion exchange reaction, for example, JP-A-2007-145797 can be referred to.

[0227] The onium salt represented by formula (5A) or (5B) acts as an acid diffusion inhibitor in the present invention. This is because each counter anion of the onium salt is a conjugate base of a weak acid. The weak acid here means an acidity that cannot deprotect the acid labile group of the acid labile group-containing unit contained in the base polymer. The onium salt represented by formula (5A) or (5B) functions as an acid diffusion inhibitor when used in combination with an onium salt-type photoacid generator having a conjugate base of a strong acid such as a sulfonic acid whose α-position is fluorinated as a counter anion. That is, when an onium salt that generates a strong acid such as a sulfonic acid whose α-position is fluorinated and an onium salt that generates a weak acid such as a sulfonic acid or a carboxylic acid that is not substituted with fluorine are mixed and used, when the strong acid generated from the photoacid generator by irradiation with high energy rays collides with an onium salt having an anion of an unreacted weak acid, the weak acid is released by salt exchange to generate an onium salt having an anion of a strong acid. In this process, the strong acid is exchanged for a weaker acid with a lower catalytic activity, and the acid appears to be deactivated, thereby enabling control of acid diffusion.

[0228] In the onium salt represented by formula (5A) or (5B), Mq + Onium salts in which the onium salt is a sulfonium cation (5C) or an iodonium cation (5D) are particularly photodegradable, and therefore the quenching ability in areas with strong light intensity decreases and the concentration of strong acid derived from the photoacid generator increases. This improves the contrast of the exposed areas, making it possible to form patterns with excellent LWR and CDU.

[0229] In addition, when the acid labile group is an acetal group that is particularly sensitive to acid, the acid for removing the protecting group does not necessarily need to be a sulfonic acid, an imide acid, or a methide acid whose α-position is fluorinated, and the deprotection reaction may proceed even with a sulfonic acid whose α-position is not fluorinated. In this case, it is preferable to use an amine compound or a carboxylate onium salt represented by formula (5B) as the acid diffusion inhibitor.

[0230] As the acid diffusion inhibitor, an onium salt of a weak acid such as fluoroalkylsulfonylamide, carbonylsulfonylimide, bis(alkylsulfonyl)imide, or tris(alkylsulfonyl)methide can be used. The anion of such an onium salt is represented by the formula (1), - Examples of the anion represented by the formula include those exemplified as the anion represented by the formula below and those represented by the formula below. [ka]

[0231] [ka]

[0232] The cation of the onium salt of the weak acid is represented by Mq in formulas (5A) and (5B). + Examples of the onium cation include those represented by the following formula:

[0233] Specific examples of the weak acid onium salts of the fluoroalkylsulfonylamides, carbonylsulfonylimides, bis(alkylsulfonyl)imides and tris(alkylsulfonyl)methides include combinations of the above anions and cations.

[0234] As the acid diffusion inhibitor, a weak acid betaine type compound can also be used. As long as it is a weak acid betaine type compound that functions as an acid diffusion inhibitor, the structure is not particularly limited, but sulfonium type or iodonium type is preferable. In addition, the acidity of the conjugate acid is preferably pKa=1 to 7. Specific examples thereof include, but are not limited to, the following. [ka]

[0235] The acid diffusion inhibitor may contain Cl as an anion. - , Br - , NO3 -It is also possible to use sulfonium salts or iodonium salts having the following structure. Specific examples thereof include triphenylsulfonium chloride, diphenyliodonium chloride, triphenylsulfonium bromide, triphenylsulfonium nitrate, 4-tert-butylphenyl(diphenyl)sulfonium chloride, bis(4-tert-butylphenyl)phenylsulfonium chloride, tris(4-tert-butylphenyl)sulfonium chloride, 4-tert-butylphenyl(diphenyl)sulfonium nitrate, bis(4-tert-butylphenyl)phenylsulfonium nitrate, tris(4-tert-butylphenyl)sulfonium nitrate, S-phenyldibenzothiophenium chloride, S-phenyldibenzothiophenium nitrate, bis(tert-butylphenyl)iodonium chloride, and bis(tert-butylphenyl)iodonium nitrate. These anions have low boiling points of conjugate acids, so that the acid generated after quenching of the strong acid is easily removed from the resist film by post-exposure bake (PEB) or the like. Since the acid is removed from the resist film to the outside of the system, acid diffusion is highly suppressed, and contrast is improved.

[0236] As the acid diffusion inhibitor, a photodecomposable onium salt having a nitrogen-containing substituent can also be used. The photodecomposable onium salt functions as an acid diffusion inhibitor in the unexposed area, and functions as a so-called photodecomposable base in the exposed area, which loses its acid diffusion inhibitory ability by neutralizing with the acid generated from itself. By using a photodecomposable base, the contrast between the exposed area and the unexposed area can be further enhanced. For example, JP-A-2009-109595, JP-A-2012-46501, JP-A-2013-209360, etc. can be referred to as the photodecomposable base.

[0237] Specific examples of the anion of the photodecomposable onium salt include, but are not limited to, those shown below. HF is a hydrogen atom or a trifluoromethyl group. [ka]

[0238] Specific examples of the cation of the photodecomposable onium salt include those exemplified as the cations in the formulae (d1) to (d3) and those exemplified as the cation of the iodonium salt represented by the formula (3B), and the following are preferred: In the following formulae, Me is a methyl group, and tBu is a tert-butyl group. [ka]

[0239] Specific examples of the photodecomposable onium salt include, but are not limited to, combinations of the above anions and cations.

[0240] The content of the (C) component is preferably 2 to 30 parts by mass, more preferably 5 to 30 parts by mass, and even more preferably 8 to 25 parts by mass, relative to 100 parts by mass of the (A) base polymer. By blending the acid diffusion inhibitor in the above range, it is possible to easily adjust the resist sensitivity, and in addition, to suppress the diffusion speed of the acid in the resist film, improve the resolution, suppress the change in sensitivity after exposure, reduce the substrate and environmental dependency, and improve the exposure margin and pattern profile. In addition, the addition of the acid diffusion inhibitor can improve the substrate adhesion. The content of the (C) component refers to the total content of the acid diffusion inhibitor consisting of the onium salt represented by formula (1) and the content of the acid diffusion inhibitor other than the onium salt represented by formula (1). In the (C) acid diffusion inhibitor, the onium salt represented by formula (1) is preferably contained in an amount of 50 to 100% by mass. The acid diffusion inhibitor of the (C) component may be used alone or in combination of two or more.

[0241] [(D) Organic solvent] The chemically amplified resist composition of the present invention may contain an organic solvent as component (D). The organic solvent is not particularly limited as long as it is an organic solvent in which the above-mentioned and below-mentioned components can be dissolved. Examples of such organic solvents include ketones such as cyclohexanone and methyl-2-n-pentyl ketone described in paragraphs

[0144] to

[0145] of JP-A-2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, Examples of suitable solvents include ethers such as propylene glycol dimethyl ether and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, 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; and lactones such as γ-butyrolactone, and mixed solvents thereof. When an acetal-based acid labile group is used, a high-boiling alcohol solvent, specifically diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, 1,3-butanediol, etc., can also be added to accelerate the deprotection reaction of the acetal.

[0242] In the present invention, among these organic solvents, 1-ethoxy-2-propanol, propylene glycol monomethyl ether acetate, diacetone alcohol, cyclohexanone, γ-butyrolactone, ethyl lactate and mixed solvents thereof, which have particularly excellent solubility of the photoacid generator in the resist component, are preferably used. In particular, propylene glycol monomethyl ether acetate (component X) is essential, and 1-ethoxy-2-propanol, diacetone alcohol, cyclohexanone, γ-butyrolactone and ethyl lactate are also preferably used. 5The solvent system is a mixture of one or two of the above solvents (component Y), and the ratio of component X to component Y is preferably within the range of 90:10 to 30:70.

[0243] The content of the component (D) is preferably from 100 to 8,000 parts by mass, and more preferably from 400 to 6,000 parts by mass, per 100 parts by mass of the base polymer (A).

[0244] [(E) Surfactant] In addition to the above-mentioned components, the chemically amplified resist composition of the present invention may also contain a commonly used surfactant as component (E) to improve coatability.

[0245] The surfactant of the component (E) is preferably a surfactant that is insoluble or poorly soluble in water and an alkaline developer, or a surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer. Examples of such surfactants include those described in JP-A-2010-215608 and JP-A-2011-16746.

[0246] Among the surfactants described in the above publication, preferred surfactants that are insoluble or poorly soluble in water and alkaline developers include FC-4430 (manufactured by 3M), Surflon (registered trademark) S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Olfine (registered trademark) E1004 (manufactured by Nissin 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): [ka]

[0247] Here, R, Rf, A, B, C, m, and n apply only to formula (surf-1), regardless of the above description. R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. Examples of the aliphatic group include divalent ones such as ethylene group, 1,4-butylene group, 1,2-propylene group, 2,2-dimethyl-1,3-propylene group, and 1,5-pentylene group, and examples of trivalent or tetravalent ones include the following: [ka] (In the formula, the dashed lines represent bonds and are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.)

[0248] Among these, a 1,4-butylene group, a 2,2-dimethyl-1,3-propylene group, and the like are preferable.

[0249] Rf is a trifluoromethyl group or a pentafluoroethyl group, preferably a trifluoromethyl group. m is an integer of 0 to 3, n is an integer of 1 to 4, and the sum of n and m is the valence of R, which is an integer of 2 to 4. A is 1. B is an integer of 2 to 25, preferably an integer of 4 to 20. C is an integer of 0 to 10, preferably 0 or 1. The order of the constituent units in the formula (surf-1) is not specified, and they may be bonded in blocks or randomly. The production of a partially fluorinated oxetane ring-opening polymer surfactant is described in detail in the specification of U.S. Pat. No. 5,650,483.

[0250] A surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer has a function of reducing water penetration and leaching by orienting on the surface of the resist film when a resist protective film is not used in ArF immersion lithography. Therefore, it is useful for suppressing the elution of water-soluble components from the resist film and reducing damage to the exposure device, and is also useful because it is soluble during alkaline aqueous solution development after exposure and PEB, and is unlikely to become a foreign matter that causes defects. Such surfactants are insoluble or poorly soluble in water and soluble in an alkaline developer, and are polymer-type surfactants, also called hydrophobic resins, and are particularly preferred for their high water repellency and improved water slippage.

[0251] Such polymeric surfactants include those containing at least one type selected from the repeating units represented by the following formulas (6A) to (6E). [ka]

[0252] In formulas (6A) to (6E), R B is a hydrogen atom or a methyl group. 1 R is -CH2-, -CH2CH2-, -O-, or two -H separated from each other. s1 R are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. s2 R is a single bond or an alkanediyl group having 1 to 5 carbon atoms. s3 R each independently represents a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group. s3 When R is a hydrocarbyl group or a fluorinated hydrocarbyl group, -O- or -C(=O)- may be present between the carbon atoms. s4 is a (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer of 1 to 3. s5 each independently represents a hydrogen atom or the following formula: -C(=O)-OR s5A (In the formula, R s5A is a fluorinated hydrocarbyl group having 1 to 20 carbon atoms. R is a group represented by the formula: s6 represents a hydrocarbyl group having 1 to 15 carbon atoms or a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, and -O- or -C(=O)- may be present between carbon atoms.

[0253] The polymer surfactant may further contain other repeating units than the repeating units represented by formulae (6A) to (6E). Examples of the other repeating units include repeating units obtained from methacrylic acid and α-trifluoromethylacrylic acid derivatives. In the polymer surfactant, the content of the repeating units represented by formulae (6A) to (6E) in the total repeating units is preferably 20 mol % or more, more preferably 60 mol % or more, and even more preferably 100 mol %.

[0254] For the surfactant that is insoluble or slightly soluble in water and soluble in an alkaline developer, reference can also be made to JP-A-2008-122932, JP-A-2010-134012, JP-A-2010-107695, JP-A-2009-276363, JP-A-2009-192784, JP-A-2009-191151, JP-A-2009-98638, JP-A-2010-250105, and JP-A-2011-42789.

[0255] The content of the component (E) is preferably 0 to 20 parts by mass relative to 100 parts by mass of the base polymer (A). When the component (E) is contained, the content is preferably 0.001 to 15 parts by mass, more preferably 0.01 to 10 parts by mass. The surfactant of the component (E) may be used alone or in combination of two or more kinds.

[0256] [(F) Other ingredients] The chemically amplified resist composition of the present invention may contain, as other components (F), compounds that decompose with an acid to generate an acid (acid multiplying compounds), organic acid derivatives, fluorine-substituted alcohols, crosslinking agents, compounds with Mw of 3,000 or less that change in solubility in a developer by the action of an acid (dissolution inhibitors), acetylene alcohols, etc. Specifically, the acid multiplying compounds are described in detail in JP-A-2009-269953 and JP-A-2010-215608, and the content is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass, relative to 100 parts by mass of the (A) base polymer. If the content is too high, it is difficult to control acid diffusion, which may lead to deterioration of resolution and pattern shape. For details of other additives, see paragraphs

[0155] to

[0182] of JP2008-122932A, JP2009-269953A, and JP2010-215608A.

[0257] The chemically amplified resist composition of the present invention, which contains an onium salt represented by formula (1) as an acid diffusion inhibitor, is a chemically amplified resist composition that produces fewer defects and has excellent lithography performance such as CDU, LWR, and DOF in photolithography using high-energy rays such as KrF excimer laser light, ArF excimer laser light, EB, and EUV as a light source.

[0258] [Pattern formation method] The pattern forming method of the present invention includes the steps of forming a resist film on a substrate using the above-mentioned chemically amplified resist composition, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0259] The substrate may be, for example, 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.).

[0260] The resist film can be formed, for example, by applying the resist composition onto a substrate by a method such as spin coating so that the film thickness is preferably 10 to 2,000 nm, and then pre-baking the applied composition on a hot plate preferably at 60 to 180° C. for 10 to 600 seconds, more preferably at 70 to 150° C. for 15 to 300 seconds.

[0261] When KrF excimer laser light, ArF excimer laser light, or EUV is used for exposing the resist film, a mask for forming a desired pattern is used, and the exposure amount is preferably 1 to 200 mJ / cm. 2 , more preferably 10 to 100 mJ / cm 2 When EB is used, the exposure dose is preferably 1 to 300 μC / cm 2 , either directly or through a mask for forming a desired pattern. 2 , more preferably 10 to 200 μC / cm 2 Irradiate so that

[0262] In addition to the usual exposure method, the immersion method can be used in which a liquid with a refractive index of 1.0 or more is placed between the resist film and the projection lens. In this case, a water-insoluble protective film can also be used.

[0263] The water-insoluble protective film is used to prevent elution from the resist film and to increase the water sliding property of the film surface, and is roughly divided into two types. One is an organic solvent stripping type that needs to be stripped before alkaline aqueous solution development by an organic solvent that does not dissolve the resist film, and the other is an alkaline aqueous solution soluble type that is soluble in an alkaline developer and removes the protective film together with removing the soluble part of the resist film. The latter is based on a polymer having a 1,1,1,3,3,3-hexafluoro-2-propanol residue that is insoluble in water and soluble in an alkaline developer, and is preferably a material dissolved in an alcohol-based solvent having 4 or more carbon atoms, an ether-based solvent having 8 to 12 carbon atoms, or a mixed solvent thereof. The above-mentioned water-insoluble and alkaline developer-soluble surfactant can also be dissolved in an alcohol-based solvent having 4 or more carbon atoms, an ether-based solvent having 8 to 12 carbon atoms, or a mixed solvent thereof.

[0264] After the exposure, a post-exposure bake (PEB) may be performed as necessary. The PEB can be performed, for example, by heating on a hot plate at preferably 60 to 150° C. for 1 to 5 minutes, more preferably 80 to 140° C. for 1 to 3 minutes.

[0265] Development can be carried out by a conventional method such as a dip method, a puddle method, or a spray method, using, for example, a developer such as an alkaline aqueous solution of preferably 0.1 to 5 mass %, more preferably 2 to 3 mass % tetramethylammonium hydroxide (TMAH) or the like, or an organic solvent developer, for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes.

[0266] A method for forming a positive pattern using an alkaline aqueous solution as a developer is described in detail in paragraphs

[0138] to

[0146] of JP 2011-231312 A, and a method for forming a negative pattern using an organic solvent as a developer is described in detail in paragraphs

[0173] to

[0183] of JP 2015-214634 A.

[0267] As a means for forming a pattern, after forming a resist film, a pure water rinse (post soak) may be performed to extract an acid generator and the like from the film surface or to wash away particles, or a rinse (post soak) may be performed to remove water remaining on the film after exposure.

[0268] Furthermore, a pattern can be formed by a double patterning method. Examples of double patterning methods include a trench method in which a 1:3 trench pattern is processed by a first exposure and etching, and a 1:3 trench pattern is formed by a second exposure with a shifted position to form a 1:1 pattern, and a line method in which a first base of a 1:3 isolated leave pattern is processed by a first exposure and etching, and a 1:3 isolated leave pattern is processed by a second exposure with a shifted position to form a 1:1 pattern with half the pitch.

[0269] Furthermore, when forming a hole pattern by negative tone development using an organic solvent-containing developer, light with the highest contrast can be used by performing exposure using dipole illumination with two line patterns in the X-axis and Y-axis directions. Furthermore, contrast can be further increased by adding s-polarized illumination to the dipole illumination with two line patterns in the X-axis and Y-axis directions. These pattern formation methods are described in detail in JP 2011-221513 A.

[0270] Regarding the developer in the pattern formation method of the present invention, examples of the alkaline aqueous developer include the above-mentioned TMAH aqueous solution and the alkaline aqueous solution described in paragraphs

[0148] to

[0149] of JP2015-180748A, and a 2 to 3 mass % TMAH aqueous solution is preferred.

[0271] Examples of the developer for organic solvent development 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 crotonate, and ethyl crotonate. , 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 phenylacetate, 2-phenylethyl acetate, etc. These solvents may be used alone or in combination of two or more.

[0272] The developed hole pattern or trench pattern can also be shrunk by thermal flow, RELACS (Resolution Enhancement Lithography Assisted by Chemical Shrink) technology, DSA (Directed Self-Assembly) technology, etc. A shrink agent is applied onto the hole pattern, and crosslinking of the shrink agent occurs on the surface of the resist due to diffusion of an acid catalyst from the resist film during baking, and the shrink agent adheres to the sidewall of the hole pattern. The bake temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the bake time is 10 to 300 seconds. Finally, excess shrink agent is removed to shrink the hole pattern.

[0273] By using a chemically amplified resist composition containing the onium salt represented by formula (1) of the present invention as an acid diffusion inhibitor, it is possible to improve CDU, LWR, DOF Thus, fine patterns having excellent lithography performance can be easily formed. EXAMPLES

[0274] 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, etc. In the following Examples, Mw is a value measured in terms of polystyrene by GPC using tetrahydrofuran (THF) as a solvent.

[0275] [1] Synthesis of acid diffusion inhibitor [Example 1-1] Synthesis of acid diffusion inhibitor Q-1 (1) Synthesis of compound SM-2 [ka]

[0276] After mixing 24.5g of compound SM-1, 0.06g of N,N-dimethylformamide and 147.2g of methylene chloride, 25.4g of oxalyl chloride was added dropwise at room temperature. After stirring overnight at room temperature, the reaction solution was concentrated under reduced pressure at 40°C to obtain a solid. After mixing the obtained solid, 170.1g of methylene chloride and 10.4g of 2,2,2-trifluoroethanol, a mixture of 10.5g of triethylamine, 1.3g of N,N-dimethylaminopyridine and 8g of methylene chloride was added dropwise under ice cooling, and the mixture was stirred and aged. 19 After confirming that the reaction had progressed by F-NMR, 150 g of 5% by mass hydrochloric acid was added under ice cooling to stop the reaction. 180 g of hexane was added to the reaction solution and stirred, and then the aqueous layer was separated and washed twice with 75 g of diisopropyl ether. 14.4 g of sodium iodide was added to the aqueous layer, and 60 g of methylene chloride and 120 g of methyl isobutyl ketone were added and stirred for 10 minutes. After stirring, the organic layer was separated and washed four times with 90 g of pure water. The organic layer was concentrated under reduced pressure, diluted with 40 g of methylene chloride, and 200 g of diisopropyl ether was added and stirred, and the supernatant was removed. The residual oily matter was concentrated under reduced pressure at 50° C. to obtain the target compound SM-2 as an oily matter (yield: 33.5 g, yield: 74%).

[0277] (2) Synthesis of compound SM-3 [ka]

[0278] After dissolving 33.4 g of compound SM-2 in 100.2 g of methylene chloride, 8.17 g of dimethyl sulfate was added dropwise at room temperature. After stirring overnight, the reaction solution was concentrated under reduced pressure at 50° C. Methylene chloride was added to the concentrated solution to make a 50% by mass solution, and 120 g of diisopropyl ether was added and stirred. The precipitated solid was filtered, washed with diisopropyl ether, and dried under reduced pressure at 40° C. to obtain the target compound SM-3 as a solid (yield: 27.4 g, yield: 92%).

[0279] (3) Synthesis of acid diffusion inhibitor Q-1 [ka]

[0280] Compound SM-3 (5.7 g), compound SM-4 (3.47 g), methylene chloride (48 g) and pure water (16 g) were mixed and stirred at room temperature for 1 hour. After separating the organic layer, compound SM-4 (0.4 g) and pure water (18 g) were added and stirred to separate the organic layer, and this operation was repeated twice. The obtained organic layer was washed with 18 g of pure water four times and then concentrated under reduced pressure at 40°C. Methylene chloride was added to the concentrated solution to make a 50% by mass solution, and then 68 g of diisopropyl ether was added and stirred for 30 minutes. The precipitated solid was filtered, washed with diisopropyl ether, and dried under reduced pressure at 30°C to obtain the intended acid diffusion inhibitor Q-1 as a solid (yield: 6.4 g, yield: 93%).

[0281] The IR spectrum and TOFMS data of Q-1 are shown below. The nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 1 and 2. IR(D-ATR): ν= 3497, 3238, 3070, 1736, 1695, 1586, 1478, 1448, 1422, 1365, 1315, 1289, 1259, 1207, 1184, 1164, 1145, 1076, 1057, 1013, 1000, 978, 891, 824, 791, 755, 740, 683, 642, 577, 518, 503 cm -1 . MALDI TOFMS: POSITIVE M + 389.1(C 21 H 16 F3O2S + equivalent) NEGATIVE M - 211.0(C4HF6O3 - equivalent)

[0282] [Example 1-2] Synthesis of acid diffusion inhibitor Q-2 [ka]

[0283] Compound SM-3 5.0g, compound SM-5 8.0g, methyl isobutyl ketone 56g, methanol 5g and pure water 30g were mixed and stirred at room temperature for 1 hour. The organic layer was separated and washed with 30g of pure water three times and with 30g of 20% by mass aqueous methanol solution three times. The obtained organic layer was concentrated under reduced pressure at 45°C. 80g of diisopropyl ether was added to the concentrated liquid and stirred for 1 hour, and then the supernatant liquid was removed. The operation of adding 50g of diisopropyl ether, stirring and removing the supernatant liquid was repeated twice. The residue was diluted with methylene chloride, and then 40g of diisopropyl ether was added and stirred. The precipitated solid was filtered and dried under reduced pressure at 50°C to obtain the target acid diffusion inhibitor Q-2 as a solid (yield: 8.3g, yield: 80%).

[0284] The TOFMS data of Q-2 is shown below. The nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 3 and 4. MALDI TOFMS: POSITIVE M + 389.1(C 21 H 16 F3O2S + equivalent) NEGATIVE M - 648.8(C 13 H 10 F2I3O4 - equivalent)

[0285] [Example 1-3] Synthesis of acid diffusion inhibitor Q-3 (1) Synthesis of compound SM-6 [ka]

[0286] After mixing 24.5g of compound SM-1, 0.06g of N,N-dimethylformamide and 147.2g of methylene chloride, 25.4g of oxalyl chloride was added dropwise at room temperature. After stirring overnight at room temperature, the reaction solution was concentrated under reduced pressure at 40°C to obtain a solid. After mixing the obtained solid, 170.1g of methylene chloride and 10g of methanol, a mixture of 10.5g of triethylamine, 1.3g of N,N-dimethylaminopyridine and 10g of methylene chloride was added dropwise under ice cooling, and the mixture was stirred at room temperature for 2 hours. Under ice cooling, 150g of 5% by mass hydrochloric acid was added to stop the reaction, 180g of hexane was added to the reaction solution and stirred, and the aqueous layer was separated and washed twice with 75g of diisopropyl ether. 14.4g of sodium iodide was added to the aqueous layer, and 60g of methylene chloride and 120g of methyl isobutyl ketone were further added and stirred for 10 minutes. After stirring, the organic layer was separated and washed five times with 100 g of pure water. The organic layer was concentrated under reduced pressure, 200 g of diisopropyl ether was added, and the mixture was stirred, after which the supernatant was removed. The residual oily matter was concentrated under reduced pressure at 50°C to obtain the target compound SM-6 as an oily matter (yield: 29.5 g, yield: 83%).

[0287] (2) Synthesis of compound SM-7 [ka]

[0288] After dissolving 29.4 g of compound SM-6 in 88.2 g of methylene chloride, 9.1 g of dimethyl sulfate was added dropwise at room temperature. After stirring for 2 hours, the reaction solution was concentrated under reduced pressure at 50°C. Methylene chloride was added to the concentrated solution to make a 50% by mass solution, and then 113.7 g of diisopropyl ether was added and stirred. The precipitated solid was filtered, washed with diisopropyl ether, and dried under reduced pressure at 40°C to obtain the target compound SM-7 as a solid (yield: 23.4 g, yield: 82%).

[0289] (3) Synthesis of acid diffusion inhibitor Q-3 [ka]

[0290] 4.3 g of compound SM-7, 7.9 g of a 38.6 mass% aqueous solution of compound SM-8, 30 g of methylene chloride, and 15 g of pure water were mixed, and then stirred at room temperature for 15 minutes. After separating the organic layer, 0.9 g of a 38.6 mass% aqueous solution of compound SM-8 and 15 g of pure water were added and stirred, and the operation of separating the organic layer was performed twice. The obtained organic layer was washed three times with 15 g of pure water, and then concentrated under reduced pressure at 40 ° C. The concentrated liquid was diluted with methylene chloride, 5 g of diisopropyl ether was added and stirred, and the supernatant liquid was removed. The residue was diluted with 5 g of methylene chloride, 10 g of diisopropyl ether was added and stirred, and the precipitated solid was filtered, washed with diisopropyl ether, and dried under reduced pressure at 40 ° C. to obtain the target acid diffusion inhibitor Q-3 as a solid (yield: 4.9 g, yield: 90%).

[0291] The IR spectrum and TOFMS data of Q-3 are shown below. The nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 5 and 6. IR(D-ATR): ν= 3072, 2961, 1707, 1589, 1476, 1441, 1378, 1293, 1 25 3, 1212, 1187, 1165, 1142, 1118, 1074, 1055, 998, 978, 956, 788, 752, 738, 683, 653, 529, 517, 504cm -1 . MALDI TOFMS: POSITIVE M + 321.1(C 20 H 17 O2S + equivalent) NEGATIVE M - 211.0(C4HF6O3 - equivalent)

[0292] [Example 1-4] Synthesis of acid diffusion inhibitor Q-4 [ka]

[0293] 4.3g of compound SM-7, 7.2g of compound SM-5, 60g of methylene chloride, 0.06g of 29% by mass ammonia water, and 30g of pure water were mixed and stirred at room temperature for 10 minutes. After separating the organic layer, the mixture was washed once with a solution in which 0.43g of compound SM-7 was dissolved in 30g of pure water, and three times with 30g of pure water. The obtained organic layer was concentrated under reduced pressure at 40°C. 7g of methylene chloride was added to the concentrated liquid and stirred, and then 30g of diisopropyl ether was added and stirred for 1 hour, and the supernatant liquid was removed. After diluting the residue with acetone, 40g of diisopropyl ether was added and stirred, and the supernatant liquid was removed. The obtained oily substance was dissolved in methylene chloride, concentrated under reduced pressure at 40°C, and dried to a solid. The obtained powder was dried under reduced pressure at 50°C to obtain the target acid diffusion inhibitor Q-4 as a solid (yield: 7.4g, yield: 79%).

[0294] The TOFMS data of Q-4 is shown below. The nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 7 and 8. MALDI TOFMS: POSITIVE M + 321.1(C 20 H 17 O2S + equivalent) NEGATIVE M - 648.8(C 13 H 10 F2I3O4 - equivalent)

[0295] [Example 1-5] Synthesis of acid diffusion inhibitor Q-5 (1) Synthesis of compound SM-9 [ka]

[0296] After mixing 15.0 g of compound SM-1, 0.04 g of N,N-dimethylformamide, and 90 g of methylene chloride, 15.5 g of oxalyl chloride was added dropwise at room temperature. After stirring overnight at room temperature, the reaction solution was concentrated under reduced pressure at 40° C. to obtain a solid. After mixing the obtained solid, 90 g of methylene chloride, and 22 g of ethanol, a mixture of 9.9 g of triethylamine, 0.6 g of N,N-dimethylaminopyridine, and 10 g of methylene chloride was added dropwise under ice cooling, and the mixture was stirred at room temperature for 3.5 hours. Under ice cooling, 120 g of 5% by mass hydrochloric acid was added to stop the reaction, 150 g of hexane was added to the reaction solution and stirred, and the aqueous layer was separated and washed twice with 75 g of diisopropyl ether. 14.4 g of sodium iodide was added to the aqueous layer, and 60 g of methylene chloride and 10 g of methyl isobutyl ketone were further added and stirred for 10 minutes. After stirring, the organic layer was separated and washed five times with 50 g of pure water. The organic layer was concentrated under reduced pressure, and then 20 g of diisopropyl ether was added and stirred, and the supernatant was removed. The residual oily matter was concentrated under reduced pressure at 50°C to obtain the target compound SM-9 as an oily matter (yield: 23.7 g, yield: 99%).

[0297] (2) Synthesis of compound SM-10 [ka]

[0298] After dissolving 22.6 g of compound SM-9 in 67.8 g of methylene chloride, 6.8 g of dimethyl sulfate was added dropwise at room temperature. After stirring overnight, the reaction solution was concentrated under reduced pressure at 50° C. to precipitate a solid. After adding 30 g of diisopropyl ether to the solid and stirring, the solid was filtered, washed with diisopropyl ether, and dried under reduced pressure at 40° C. to obtain the target compound SM-10 as a solid (yield: 16.2 g, yield: 74%).

[0299] (3) Synthesis of acid diffusion inhibitor Q-5 [ka]

[0300] 4.5g of compound SM-10, 6.0g of a 38.6% by mass aqueous solution of compound SM-8, 31g of methylene chloride, and 15g of pure water were mixed, and then stirred at room temperature for 20 minutes. The organic layer was separated, washed with 20g of pure water five times, and concentrated under reduced pressure at 40°C. 10g of diisopropyl ether was added to the concentrated liquid, stirred, and the supernatant liquid was removed. 10g of diisopropyl ether and 10g of hexane were added to the residue, stirred, and the precipitated solid was filtered, washed with diisopropyl ether, and dried under reduced pressure at 40°C to obtain the target acid diffusion inhibitor Q-5 as a solid (yield: 4.9g, yield: 91%).

[0301] The IR spectrum and TOFMS data of Q-5 are shown below. The nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 9 and 10. IR(D-ATR): ν= 3494, 3379, 3248, 3096, 3000, 2976, 2934, 1745, 1698, 1585, 1478, 1466, 1447, 1409, 1371, 1289, 1249, 1199, 1149, 1111, 1076, 1053, 1023, 1000, 980, 872, 858, 793, 765, 758, 747, 741, 682, 612, 594, 519, 506, 495cm -1 . MALDI TOFMS: POSITIVE M + 335.1(C 21 H 19 O2S + equivalent) NEGATIVE M - 211.0(C4HF6O3 - equivalent)

[0302] [Example 1-6] Synthesis of acid diffusion inhibitor Q-6 [ka]

[0303] Compound SM-10 (4.5 g), compound SM-5 (7.2 g), methylene chloride (50 g) and pure water (25 g) were mixed and stirred at room temperature for 15 minutes. The organic layer was separated and washed twice with a solution of compound SM-9 (0.41 g) dissolved in pure water (25 g) and seven times with pure water (30 g). The organic layer was concentrated under reduced pressure at 40°C. Diisopropyl ether (20 g) and hexane (10 g) were added to the concentrated solution and stirred overnight. The precipitated solid was filtered off and the powder was dried under reduced pressure at 40°C to obtain the intended acid diffusion inhibitor Q-6 as a solid (yield: 8.3 g, yield: 92%).

[0304] The TOFMS data of Q-6 is shown below. The nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 11 and 12. MALDI TOFMS: POSITIVE M + 335.1(C 21 H 19 O2S + equivalent) NEGATIVE M - 648.8(C 13 H 10 F2I3O4 - equivalent)

[0305] [Example 1-7] Synthesis of acid diffusion inhibitor Q-7 (1) Synthesis of compound SM-11 [ka]

[0306] After mixing 15.0 g of compound SM-1, 0.04 g of N,N-dimethylformamide, and 90 g of methylene chloride, 15.5 g of oxalyl chloride was added dropwise at room temperature. After stirring overnight at room temperature, the reaction solution was concentrated under reduced pressure at 40° C. to obtain a solid. After mixing the obtained solid, 90 g of methylene chloride, and 37 g of ethylene glycol monomethyl ether, a mixture of 9.9 g of triethylamine, 0.6 g of N,N-dimethylaminopyridine, and 10 g of methylene chloride was added dropwise under ice cooling, and the mixture was stirred at room temperature for 23 hours. Under ice cooling, 120 g of 5% by mass hydrochloric acid was added to stop the reaction, 150 g of hexane was added to the reaction solution and stirred, and the aqueous layer was separated and washed twice with 75 g of diisopropyl ether. 10 g of sodium iodide was added to the aqueous layer, and 150 g of methylene chloride and 10 g of methyl isobutyl ketone were added and stirred for 10 minutes. After stirring, the organic layer was separated and washed five times with 100 g of pure water. The organic layer was concentrated under reduced pressure, and then 30 g of diisopropyl ether was added and stirred, and the supernatant was removed. The residual oily matter was concentrated under reduced pressure at 50°C to obtain the target compound SM-11 as an oily matter.

[0307] (2) Synthesis of compound SM-12 [ka]

[0308] After dissolving 21.3 g of compound SM-11 in 67.8 g of methylene chloride, 6.8 g of dimethyl sulfate was added dropwise at room temperature. After stirring overnight, the reaction solution was concentrated under reduced pressure at 50°C. 30 g of diisopropyl ether was added to the concentrated solution and stirred for 10 minutes, and the supernatant was removed. 30 g of diisopropyl ether and 10 g of hexane were added to the residue and stirred, and the supernatant was removed. The remaining oily matter was concentrated under reduced pressure at 50°C to obtain the target compound SM-12 as an oily matter (yield: 20.6 g, yield: 84% (two steps)).

[0309] (3) Synthesis of acid diffusion inhibitor Q-7 [ka]

[0310] 4.8 g of compound SM-12, 5.5 g of a 38.6 mass% aqueous solution of compound SM-8, 33 g of methylene chloride, and 16 g of pure water were mixed, and then stirred at room temperature for 10 minutes. The organic layer was separated, and then washed twice with 0.5 g of a 38.6 mass% aqueous solution of compound SM-8 and 20 g of pure water, and seven times with 20 g of pure water. The obtained organic layer was concentrated under reduced pressure at 40°C. 10 g of diisopropyl ether and 2 mL of hexane were added to the concentrated liquid and stirred, and the precipitated solid was filtered, washed with diisopropyl ether, and dried under reduced pressure at 40°C to obtain the target acid diffusion inhibitor Q-7 as a solid (yield: 3.8 g, yield: 69%).

[0311] The IR spectrum and TOFMS data of Q-7 are shown below. The nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 13 and 14. IR(D-ATR): ν= 3071, 3024, 2956, 2888, 2847, 1712, 1589, 1480, 1454, 1406, 1369, 1295, 1280, 1245, 1216, 1180, 1157, 1144, 1114, 1095, 1076, 1055, 1041, 1025, 996, 976, 874, 826, 806, 788, 760, 744, 703, 692, 682, 654, 530, 516, 495cm -1 . MALDI TOFMS: POSITIVE M + 365.1(C 22 H 21 O3S + equivalent) NEGATIVE M - 211.0(C4HF6O3 - equivalent)

[0312] [Example 1-8] Synthesis of acid diffusion inhibitor Q-8 [ka]

[0313] 1.5g of compound SM-12, 2.2g of compound SM-5, 10g of methylene chloride and 5g of pure water were mixed and stirred at room temperature for 15 minutes. After separating the organic layer, it was washed twice with a solution of 0.1g of compound SM-11 dissolved in 10g of pure water and five times with 15g of pure water. The obtained organic layer was concentrated under reduced pressure at 40°C. After diluting the concentrated liquid with 2g of methylene chloride, 5g of diisopropyl ether was added and stirred overnight, and the supernatant liquid was removed. The residual oily matter was concentrated under reduced pressure at 40°C to obtain the target acid diffusion inhibitor Q-8 as an oily matter (yield: 1.1g, yield: 34%).

[0314] The TOFMS data of Q-8 is shown below. The nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 15 and 16. MALDI TOFMS: POSITIVE M + 365.1(C 22 H 21 O3S + equivalent) NEGATIVE M - 648.8(C 13 H 10 F2I3O4 - equivalent)

[0315] [Example 1-9] Synthesis of acid diffusion inhibitor Q-9 (1) Synthesis of compound SM-14 [ka]

[0316] After mixing 6.0 g of compound SM-13, 0.01 g of N,N-dimethylformamide, and 42 g of methylene chloride, 5.8 g of oxalyl chloride was added dropwise at room temperature. After stirring overnight at room temperature, the reaction solution was concentrated under reduced pressure at 40°C. After mixing 42 g of methylene chloride and 40 g of methanol with the concentrated solution, a mixture of 3.7 g of triethylamine, 0.2 g of N,N-dimethylaminopyridine, and 10 g of methylene chloride was added dropwise under ice cooling, and the mixture was stirred overnight at room temperature. Under ice cooling, 50 g of 5% by mass hydrochloric acid was added to stop the reaction, 50 g of hexane was added to the reaction solution, and the mixture was stirred, and the aqueous layer was separated and washed twice with 30 g of diisopropyl ether. 10 g of sodium iodide was added to the aqueous layer, and 60 g of methylene chloride was added and stirred for 10 minutes. After stirring, the organic layer was separated and the organic layer was washed five times with 50 g of pure water. The organic layer was concentrated under reduced pressure at 40° C. and dried to obtain the target compound SM-14 as a solid (yield: 8.6 g, 98%).

[0317] (2) Synthesis of compound SM-15 [ka]

[0318] After dissolving 8.6 g of compound SM-14 in 60.2 g of methylene chloride, 2.5 g of dimethyl sulfate was added dropwise at room temperature. After stirring overnight, the reaction solution was concentrated under reduced pressure at 40° C. 20 g of diisopropyl ether was added to the concentrated solution and stirred for 1 hour, after which the precipitated solid was filtered off, washed with diisopropyl ether, and concentrated under reduced pressure at 40° C. to obtain the target compound SM-15 as a solid (yield: 7.3 g, yield: 86%).

[0319] (3) Synthesis of acid diffusion inhibitor Q-9 [ka]

[0320] 4.5g of compound SM-15, 5.5g of 38.6% by mass aqueous solution of compound SM-8, 31g of methylene chloride and 15g of pure water were mixed and stirred at room temperature for 15 minutes. After separating the organic layer, it was washed twice with 0.5g of 38.6% by mass aqueous solution of compound SM-8 and 15g of pure water, and five times with 40g of pure water. The obtained organic layer was concentrated under reduced pressure at 40°C. After adding 10g of methylene chloride and 20g of diisopropyl ether to the concentrated liquid and stirring, the precipitated solid was filtered, washed with diisopropyl ether, and dried under reduced pressure at 40°C to obtain the target acid diffusion inhibitor Q-9 as a solid (yield: 4.3g, yield: 85%).

[0321] The IR spectrum and TOFMS data of Q-9 are shown below. The nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 17 and 18. IR(D-ATR): ν= 3281, 3059, 2966, 1693, 1654, 1586, 1464, 1440, 1385, 1311, 1291, 1275, 1245, 1197, 1166, 1144, 1114, 1100, 1010, 993, 978, 968, 833, 795, 746, 680, 518, 506, 462cm -1 . MALDI TOFMS: POSITIVE M + 339.0(C 14 H 12 IO2 + equivalent) NEGATIVE M - 211.0(C4HF6O3 - equivalent)

[0322] [Example 1-10] Synthesis of acid diffusion inhibitor Q-10 (1) Synthesis of compound SM-16 [ka]

[0323] After mixing 6.0 g of compound SM-13, 0.01 g of N,N-dimethylformamide, and 42 g of methylene chloride, 5.8 g of oxalyl chloride was added dropwise at room temperature. After stirring overnight at room temperature, the reaction solution was concentrated under reduced pressure at 40°C. After mixing 42 g of methylene chloride and 40 g of ethanol with the concentrated solution, a mixture of 3.7 g of triethylamine, 0.2 g of N,N-dimethylaminopyridine, and 10 g of methylene chloride was added dropwise under ice cooling, and the mixture was stirred overnight at room temperature. Under ice cooling, 50 g of 5% by mass hydrochloric acid was added to stop the reaction, 50 g of hexane was added to the reaction solution, and the mixture was stirred, and the aqueous layer was separated and washed twice with 30 g of diisopropyl ether. 10 g of sodium iodide was added to the aqueous layer, and 60 g of methylene chloride was added and stirred for 10 minutes. After stirring, the organic layer was separated and the organic layer was washed five times with 50 g of pure water. The organic layer was concentrated under reduced pressure at 40° C. and dried to obtain the target compound SM-16 as a solid (yield: 7.9 g, 86%).

[0324] (2) Synthesis of compound SM-17 [ka]

[0325] After dissolving 7.9 g of compound SM-16 in 56 g of methylene chloride, 2.2 g of dimethyl sulfate was added dropwise at room temperature. After stirring overnight, the reaction solution was concentrated under reduced pressure at 40°C. After adding 10 g of methylene chloride and 20 g of diisopropyl ether to the concentrated solution and stirring, the precipitated solid was filtered off. After redissolving in 10 g of methylene chloride, 20 g of diisopropyl ether was added to recrystallize, filtered, and concentrated under reduced pressure at 40°C to obtain the target compound SM-17 as a solid (yield: 5.8 g, yield: 74%).

[0326] (3) Synthesis of acid diffusion inhibitor Q-10 [ka]

[0327] 4.7g of compound SM-17, 5.5g of 38.6% by mass aqueous solution of compound SM-8, 31g of methylene chloride and 15g of pure water were mixed and stirred at room temperature for 15 minutes. After separating the organic layer, it was washed twice with 0.2g of 38.6% by mass aqueous solution of compound SM-8 and 15g of pure water, and five times with 30g of pure water. The obtained organic layer was concentrated under reduced pressure at 40°C. After adding 10g of methylene chloride and 20g of diisopropyl ether to the concentrated liquid and stirring, the precipitated solid was filtered, washed with diisopropyl ether, and dried under reduced pressure at 40°C to obtain the target acid diffusion inhibitor Q-10 as a solid (yield: 4.8g, yield: 92%).

[0328] The IR spectrum data and TOFMS data of Q-10 are shown below. The nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 19 and 20. IR(D-ATR): ν= 6260, 3102, 3072, 3001, 1681, 1662, 1585, 1567, 1477, 1460, 1444, 1378, 1310, 1293, 1276, 1245, 1196, 1165, 1111, 1068, 1054, 1043, 1017, 993, 978, 924, 876, 862, 839, 794, 746, 680, 557, 519, 473, 462cm -1 . MALDI TOFMS: POSITIVE M + 353.0(C 15 H 14 IO2 + equivalent) NEGATIVE M - 211.0(C4HF6O3 - equivalent)

[0329] [Examples 1-11 to 1-25] With reference to the above-mentioned Examples, the following acid diffusion inhibitors Q-11 to Q-25 were synthesized. [ka]

[0330] [ka]

[0331] [2] Synthesis of base polymer [Synthesis Example 1] Synthesis of base polymer P-1 Under a nitrogen atmosphere, 22 g of 1-tert-butylcyclopentyl methacrylate, 17 g of 2-oxotetrahydrofuran-3-yl methacrylate, 0.49 g of V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 0.40 g of 2-mercaptoethanol, and 50 g of methyl ethyl ketone were taken to prepare a monomer-polymerization initiator solution. 23 g of methyl ethyl ketone was taken in another flask under a nitrogen atmosphere, and the mixture was heated to 80° C. with stirring, and then the monomer-polymerization initiator solution was dropped over 4 hours. After the dropwise addition, the temperature of the polymerization liquid was kept at 80° C. and the mixture was stirred for 2 hours, and then cooled to room temperature. The obtained polymerization liquid was dropped into 640 g of vigorously stirred methanol, and the precipitated solid was filtered off. The obtained solid was washed twice with 240 g of methanol and vacuum dried at 50° C. for 20 hours to obtain 36 g of white powdery base polymer P-1 (yield 90%). Analysis by GPC revealed that Mw was 7,800 and Mw / Mn was 1.80. [ka]

[0332] [Synthesis Examples 2 to 4] Synthesis of base polymers P-2 to P-4 The following base polymers P-2 to P-4 were produced in the same manner as in Synthesis Example 1, except that the types and compounding ratios of each monomer were changed. [ka]

[0333] [3] Preparation of resist composition [Examples 2-1 to 2-58, Comparative Examples 1-1 to 1-36] The acid diffusion inhibitors (Q-1 to Q-25), base polymers (P-1 to P-4), photoacid generators (PAG-1 to PAG-4), other acid diffusion inhibitors (QA to QN) and alkali-soluble surfactant (SF-1) were dissolved in a solvent containing 0.01 mass % of the surfactant Polyfox636 (manufactured by Omnova) in the compositions shown in Tables 1 to 5 below to prepare solutions, and the resulting solutions were filtered through a 0.2 μm Teflon (registered trademark) filter to prepare resist compositions.

[0334] In Tables 1 to 5, the components are as follows. Photoacid generator: PAG-1~PAG-4 [ka]

[0335] Solvent: PGMEA (propylene glycol monomethyl ether acetate) GBL (γ-butyrolactone) CyHO (Cyclohexanone) DAA (Diacetone Alcohol)

[0336] Acid diffusion inhibitors: QA~QN [ka]

[0337] [ka]

[0338] Alkaline-soluble surfactant (SF-1): Poly(methacrylic acid = 2,2,3,3,4,4,4-heptafluoro-1-isobutyl-1-butyl methacrylate = 9-(2,2,2-trifluoro-1-trifluoromethylethyloxycarbonyl)-4-oxatricyclo[4.2.1.0 3,7 ]nonane-5-on-2-yl) [ka]

[0339] [Table 1]

[0340] [Table 2]

[0341] [Table 3]

[0342] [Table 4]

[0343] [Table 5]

[0344] [4] ArF lithography evaluation [Examples 3-1 to 3-15, Comparative Examples 2-1 to 2-15] An anti-reflective film solution (ARC-29A, manufactured by Nissan Chemical Co., Ltd.) was applied onto a silicon substrate and baked at 180°C for 60 seconds to form an anti-reflective film (film thickness 100 nm). Each resist composition (R-1 to R-15, CR-1 to CR-15) was spin-coated onto the anti-reflective film and baked at 100°C for 60 seconds using a hot plate to form a resist film with a film thickness of 90 nm. Immersion exposure was performed using an ArF excimer laser scanner (NSR-S610C, manufactured by Nikon Corporation, NA=1.30, σ0.94 / 0.74, Dipole-35deg illumination, 6% halftone phase shift mask). Water was used as the immersion liquid. Thereafter, baking (PEB) was performed at 90°C for 60 seconds, and development was performed with a 2.38 mass% TMAH aqueous solution for 60 seconds to form a line and space (LS) pattern.

[0345] The developed LS pattern was observed with a critical dimension SEM (CG5000) manufactured by Hitachi High-Technologies Corporation, and the sensitivity, LWR and defect density were evaluated according to the following methods. The results are shown in Tables 6 and 7.

[0346] [Sensitivity evaluation] The optimum exposure dose E for obtaining an LS pattern with a line width of 40 nm and a pitch of 80 nm is op (mJ / cm 2 The smaller this value, the higher the sensitivity.

[0347] [LWR rating] E op The dimensions of the LS pattern obtained by irradiating with 10000 times the light were measured in the longitudinal direction of the lines, and the LWR was calculated as three times the standard deviation (σ) (3σ). The smaller this value, the less roughness and the more uniform the line width of the pattern obtained. In this evaluation, the criteria were as follows: good (A): 2.5 nm or less, and bad (x): greater than 2.5 nm.

[0348] [Defect density evaluation] The number of defects in the pattern formed after development was inspected using a defect inspection device KLA2905 (manufactured by KLA-Tenco), and the defect density was calculated according to the following formula. Defect density (pcs / cm 2 ) = Total number of defects detected / Inspection area Defect inspection conditions: Light source UV, inspection pixel size 0.22 μm, array mode In this evaluation, ◎: 0.03 particles / cm 2 Less than 0.03 pieces / cm 2 More than 0.05 pieces / cm 2 Less than 0.05 pieces / cm 2 That's all.

[0349] [Table 6]

[0350] [Table 7]

[0351] The results shown in Tables 6 and 7 demonstrate that the chemically amplified resist composition of the present invention has fewer defects and excellent LWR, and is suitable as a material for ArF immersion lithography.

[0352] [5] EUV lithography evaluation [Examples 4-1 to 4-43, Comparative Examples 3-1 to 3-17] Each resist composition (R-16 to R-58, CR-16 to CR-36) was spin-coated on a silicon substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a thickness of 20 nm, and the substrate was pre-baked at 105°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. This was exposed using an EUV scanner NXE3300 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, a hole pattern mask with a pitch of 46 nm on the wafer and a +20% bias), and PEB was performed on a hot plate at 85°C 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 a dimension of 23 nm.

[0353] The hole pattern after development was observed with a critical dimension SEM (CG5000) manufactured by Hitachi High-Technologies Corporation, and the sensitivity, CDU and DOF were evaluated according to the following methods. The results are shown in Tables 8 to 10.

[0354] [Sensitivity evaluation] As the sensitivity, the optimum exposure dose E when the hole size is formed at 23 nm op (mJ / cm 2 The smaller this value, the higher the sensitivity.

[0355] [CDU Rating] E op The dimensions of 50 holes in the same exposure shot were measured, and the CDU was calculated as three times the standard deviation (σ). The smaller this value, the better the dimensional uniformity of the hole pattern. In this evaluation, the criteria were as follows: good (A): 3.0 nm or less, and bad (x): greater than 3.0 nm.

[0356] [DOF evaluation] The optimal exposure amount E op The focus was changed stepwise to form a hole pattern, and the focus range in which the dimensions of the obtained hole pattern were within a range of 23 nm ± 5% (21.85 to 24.15 nm) was determined as the DOF. The larger this value, the smaller the change in pattern dimensions with respect to the change in DOF, and the better the DOF. In this evaluation, the following criteria were met: good (◎): 90 nm or more, fair (◯): 85 to 90 nm, and poor (×): 85 nm or less.

[0357] [Table 8]

[0358] [Table 9]

[0359] [Table 10]

[0360] The results shown in Tables 8 to 10 demonstrate that the chemically amplified resist composition of the present invention has excellent CDU and DOF and is suitable as a material for EUV lithography.

Claims

1. An onium salt represented by the following formula (1): 【Chemistry 1】 (In the formula, X is a sulfur atom. n is 1. R 1 is a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a 1-trifluoromethyl-2,2,2-trifluoroethyl group, or a 2-methoxyethyl group. R 2 and R 3 each independently represents a phenyl group which may be substituted with at least one substituent selected from a fluorine atom, an iodine atom, a trifluoromethyl group, a trifluoromethoxy group, a methyl group, a tert-butyl group, a hydroxy group, a methoxy group, a butoxy group, a mexyethoxy group, a tert-butoxy group, a cyclohexylsulfonyl group, and an acetyl group; R 2 and R 3 may be bonded to each other to form a ring together with the X to which they are attached. Ar is an arylene group having 6 to 14 carbon atoms, which is optionally substituted with a substituent selected from a halogen atom, a hydroxy group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, and a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. Z - is a carboxylate anion, a sulfonamide anion, a sulfonimide anion, or a methide anion.

2. The onium salt according to claim 1, represented by the following formula (2): 【Chemistry 2】 (In the formula, R 1 , R 2 , R 3 , n, X and Z - is the same as above. R 4 represents a halogen atom, a hydroxy group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, or a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. m is an integer from 0 to 4.

3. A cation represented by any one of the following formulas and Z - (Z - is a carboxylate anion, a sulfonamide anion, a sulfonimide anion, or a methide anion. 【Chemistry 3】

4. Z - The onium salt according to any one of claims 1 to 3, wherein the anion has one or more fluorine atoms or trifluoromethyl groups at the α- or β-position of the carboxyl group.

5. An onium salt represented by the following formula (1): 【Chemistry 4】 (In the formula, X is an iodine atom. n is 0. R 1 is a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a 1-trifluoromethyl-2,2,2-trifluoroethyl group, or a 2-methoxyethyl group. R 2 and R 3 each independently represents a phenyl group which may be substituted with at least one substituent selected from a fluorine atom, an iodine atom, a trifluoromethyl group, a trifluoromethoxy group, a methyl group, a tert-butyl group, a hydroxy group, a methoxy group, a butoxy group, a mexyethoxy group, a tert-butoxy group, a cyclohexylsulfonyl group, and an acetyl group; R 2 and R 3 may be bonded to each other to form a ring together with the X to which they are attached. Ar is an arylene group having 6 to 14 carbon atoms, which is optionally substituted with a substituent selected from a halogen atom, a hydroxy group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, and a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. Z - is a carboxylate anion having one or more fluorine atoms or trifluoromethyl groups at the α- or β-position of the carboxyl group.

6. Z - The onium salt according to any one of claims 1 to 5, wherein is an anion represented by any one of the following formulas (Z-1) to (Z-5): 【Chemistry 5】 (In the formula, R 11 is a perfluoroalkyl group having 1 to 4 carbon atoms. R 12 and R 13 are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 12 and R 13 At least one of the groups is a fluorine atom or a trifluoromethyl group. R 14 and R 15 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 15 carbon atoms which may contain a heteroatom. R 16 , R 17 and R 18 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. L 1 and L 2 are each independently a single bond, a carbonyl group, or a sulfonyl group.

7. An acid diffusion inhibitor comprising the onium salt according to any one of claims 1 to 6.

8. 8. A chemically amplified resist composition comprising: (A) a base polymer; (B) a photoacid generator; (C-1) the acid diffusion inhibitor according to claim 7; and (D) an organic solvent.

9. (A') a base polymer having a function of generating an acid upon exposure to light; and (C-1) a photoresist according to claim 7 A chemically amplified resist composition comprising the acid diffusion inhibitor described above and (D) an organic solvent.

10. 10. The chemically amplified resist composition according to claim 8, wherein the base polymer is a polymer containing a repeating unit represented by the following formula (a) or a repeating unit represented by the following formula (b): 【Chemistry 6】 (In the formula, R A are each independently a hydrogen atom or a methyl group. X A represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-O-X A1 - is. A1 is a hydrocarbylene group having 1 to 15 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring. X B is a single bond or an ester bond. A.L. 1 and A.L. 2 are each independently an acid labile group.

11. 11. The chemically amplified resist composition according to claim 10, wherein the acid labile group is a group represented by the following formula (L1): 【Chemistry 7】 (In the formula, R 21 represents a hydrocarbyl group having 1 to 7 carbon atoms, and —CH 2 - may be replaced by -O-. a is 1 or 2. The dashed line represents a bond.

12. 12. The chemically amplified resist composition according to claim 8, wherein the base polymer is a polymer containing a repeating unit represented by the following formula (c): 【Chemistry 8】 (In the formula, R A is a hydrogen atom or a methyl group. Y A is a single bond or an ester bond. R 22 is a fluorine atom, an iodine atom, a carboxy group, a formyl group, a formyloxy group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. b and c are integers satisfying 1≦b≦5, 0≦c≦4, and 1≦b+c≦5.

13. 10. The chemically amplified resist composition according to claim 9, wherein the repeating unit capable of generating an acid upon exposure is represented by any one of the following formulas (d1) to (d4): 【Chemistry 9】 (In the formula, R A are each independently a hydrogen atom or a methyl group. R f1 , R f2 and R f3 are each independently a hydrogen atom or a trifluoromethyl group. Z A and Z B each independently represents a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. Z C is a single bond, -Z C1 -, -O-Z C1 - or -C(=O)-O-Z C1 - is. C1 is a phenylene group which may be substituted with a hydroxy group, a fluorine atom, an iodine atom, a trifluoromethyl group, a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 10 carbon atoms which may contain a heteroatom, or a hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may contain a heteroatom. Z D represents a single bond, a phenylene group, -O-Z D1 -, -C(=O)-O-Z D1 - or -C(=O)-NH-Z D1 - is. D1 is a hydrocarbylene group which may contain a heteroatom. R 31 ~R 41 are each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 31 and R 32 , R 34 and R 35 , R 37 and R 38 Or R 40 and R 41 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. k 1 is 0 or 1, but Z A When is a single bond, it is 0. 2 is 0 or 1, but Z B is a single bond, it is 0. Xa - is a non-nucleophilic counterion.)

14. A pattern forming method comprising the steps of: forming a resist film on a substrate using the chemically amplified resist composition according to any one of claims 8 to 13; exposing the resist film to KrF excimer laser light or ArF excimer laser light; and developing the exposed resist film using a developer.

15. A pattern forming method comprising the steps of: applying the chemically amplified resist composition according to any one of claims 8 to 13 onto a substrate to form a resist film on the substrate; exposing the resist film to an electron beam or extreme ultraviolet light; and developing the exposed resist film using a developer.

16. 16. The method for forming a pattern according to claim 14, wherein an aqueous alkaline solution is used as a developer to obtain a positive pattern in which exposed areas are dissolved and unexposed areas are not dissolved.

17. 16. The method for forming a pattern according to claim 14, wherein an organic solvent is used as a developer to dissolve the unexposed areas and to obtain a negative pattern in which the exposed areas are insoluble.

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