Onium salt, chemically amplified resist composition and pattern forming method

Abstract

The invention relates to an onium salt, a chemically amplified resist composition and a pattern forming method. The present invention addresses the problem of providing: a chemically amplified resist composition which has excellent LWR and resolution and is capable of suppressing collapse of a resist pattern in optical lithography using high-energy rays such as far ultraviolet lithography, EUV lithography, and electron beam (EB) lithography; an onium salt using the chemically amplified resist composition; and a pattern forming method using the chemically amplified resist composition. The onium salt is represented by the following formula (1). # imgabs0 #

Description

Technical Field

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

[0002] In recent years, with the high integration and high speed of LSI, the pattern rules are being miniaturized, and far ultraviolet lithography and extreme ultraviolet (EUV) lithography are considered promising as the next generation of microfabrication technology. Among them, optical lithography using ArF excimer laser is an indispensable technology for ultra-fine processing below 0.13μm.

[0003] ArF lithography has been partially used since the production of devices at the 130nm node, and has become the main lithography technology since the 90nm node. As for the lithography technology of the next 45nm node, 157nm lithography using F2 laser was originally considered a hope, but it was accused of delaying development due to many problems. Therefore, by inserting liquids with a higher refractive index than air such as water, ethylene glycol, glycerin, etc. between the projection lens and the wafer, the aperture number (NA) of the projection lens can be designed to be above 1.0 and high resolution can be achieved. ArF immersion lithography quickly emerged (non-patent document 1) and entered the practical stage. In this immersion lithography, a resist composition that is not easily dissolved in water is required.

[0004] ArF lithography, in order to prevent the degradation of accurate and expensive optical system materials, requires the high sensitivity resist composition that can bring into play enough resolution with less exposure. With regard to the method for realizing it, the most general is to select the highly transparent one in the wavelength 193nm as its composition. For example, for base polymer, someone proposes polyacrylic acid and derivatives thereof, norbornene-maleic anhydride alternating polymer, polynorbornene, ring-opening metathesis polymer, ring-opening metathesis polymer hydride etc., and aspect the transparency that improves resin monomer, obtains a certain degree of achievement.

[0005] In recent years, in addition to positive-tone resists developed with alkaline aqueous solutions, negative-tone resists developed with organic solvents have also received attention. In order to resolve very fine hole patterns that cannot be achieved with positive-tone exposure by negative-tone exposure, a positive-tone resist composition with high resolution is used and developed with an organic solvent to form a negative pattern. In addition, discussions are underway to obtain double the resolution by combining a second development process of alkaline aqueous solution development and organic solvent development. As for ArF resist compositions for negative-tone development using organic solvents, known positive-tone ArF resist compositions can be used, and pattern formation methods using them are described in Patent Documents 1 to 3.

[0006] In order to adapt to the rapid miniaturization in recent years, the development of process technology and resist compositions is also progressing. Various studies are also being conducted on photoacid generators, and sulfonium salts composed of triphenylsulfonium cations and perfluoroalkanesulfonic acid anions are generally used. However, as for perfluoroalkanesulfonic acids as the generated acids, perfluorooctanesulfonic acid (PFOS) has concerns about its difficulty in decomposition, bioconcentration, and toxicity, and is more stringent when used in resist compositions. Currently, photoacid generators that generate perfluorobutanesulfonic acid are used. However, if it is used in a resist composition, the diffusion of the generated acid is large, and it is difficult to achieve high resolution. In response to this problem, various partially fluorine-substituted alkanesulfonic acids and their salts have been developed. For example, Patent Document 1 describes a photoacid generator that generates α,α-difluoroalkanesulfonic acid by exposure as a prior art. Specifically, it describes a photoacid generator that generates di(4-tert-butylphenyl)iodonium 1,1-difluoro-2-(1-naphthyl)ethanesulfonate and α,α,β,β-tetrafluoroalkanesulfonic acid. However, although the fluorine substitution rates of these are all reduced, since they do not have decomposable substituents such as ester structures, the environmental safety considerations due to easy decomposition are relatively insufficient. In addition, there are limitations on the molecular design for changing the size of the alkanesulfonic acid, and the starting material containing fluorine atoms is relatively expensive.

[0007] In addition, as the circuit line width decreases, the contrast degradation caused by acid diffusion in the resist composition becomes more serious. This is because the pattern size is close to the diffusion length of the acid, and the size deviation on the wafer increases relative to the size deviation of the mask (mask error factor (MEF)), resulting in reduced mask fidelity and deterioration of pattern rectangularity. Therefore, in order to fully obtain the benefits of the short wavelength and high NA of the light source, it is necessary to increase the dissolution contrast or inhibit acid diffusion above the known materials. As one of the improvement measures, if the baking temperature is lowered, the acid diffusion will be reduced, and the MEF may be improved as a result, but it will inevitably reduce its sensitivity.

[0008] The introduction of bulky substituents and polar groups into the photoacid generator is effective in suppressing acid diffusion. Patent Document 4 describes a photoacid generator having 2-acyloxy-1,1,3,3,3-pentafluoropropane-1-sulfonic acid, which has excellent solubility and stability in resist solvents and can have a wide range of molecular designs. In particular, a photoacid generator having 2-(1-adamantyloxy)-1,1,3,3,3-pentafluoropropane-1-sulfonic acid into which a bulky substituent is introduced has a small acid diffusion. In addition, Patent Documents 5 to 7 describe photoacid generators into which condensed ring lactones, sultones, and thiolactones are introduced as polar groups. Although it has been confirmed that the performance has been improved to a certain extent due to the acid diffusion suppression effect caused by the introduction of polar groups, it is still not sufficient to control the acid diffusion to a high degree, and the photolithography performance is not satisfactory in terms of MEF, pattern shape, sensitivity, etc.

[0009] The introduction of polar groups into the anion of the photoacid generator is effective in suppressing acid diffusion, but it is disadvantageous from the perspective of solvent solubility. In Patent Documents 8 and 9, attempts have been made to improve solvent solubility by introducing alicyclic groups into the cationic portion of the photoacid generator to ensure solvent solubility. Specifically, cyclohexane rings and adamantane rings have been introduced. Although the introduction of such alicyclic groups improves solubility, a certain degree of carbon number is required to ensure solubility, resulting in a larger molecular structure volume of the photoacid generator. Therefore, when forming a fine pattern, the lithography performance such as line width roughness (LWR) and dimensional uniformity (CDU) will deteriorate.

[0010] In order to improve the dissolution contrast, an acid-labile group has been introduced into the anion or cation of the photoacid generator (Patent Documents 10, 11). Most of them have a structure in which the carboxyl group is protected by an acid-labile group. The acid-labile group undergoes a leaving reaction by the acid before and after exposure, but the generated polar group is a carboxyl group, so swelling due to the developer occurs during alkali development, and pattern collapse occurs during fine pattern formation, which has become a problem. In order to respond to the demand for further miniaturization, it is important to develop a novel photoacid generator, and it is expected to develop a photoacid generator in which acid diffusion is fully controlled, solvent solubility is excellent, and pattern collapse is effectively suppressed.

[0011] Prior art literature

[0012] Patent Literature

[0013] [Patent Document 1] Japanese Patent Application Publication No. 2008-281974

[0014] [Patent Document 2] Japanese Patent Application Publication No. 2008-281975

[0015] [Patent Document 3] Japanese Patent No. 4554665

[0016] [Patent Document 4] Japanese Patent Application Publication No. 2007-145797

[0017] [Patent Document 5] Japanese Patent No. 5061484

[0018] [Patent Document 6] Japanese Patent Application Publication No. 2016-147879

[0019] [Patent Document 7] Japanese Patent Application Publication No. 2015-63472

[0020] [Patent Document 8] Japanese Patent No. 5573098

[0021] [Patent Document 9] Japanese Patent No. 6461919

[0022] [Patent Document 10] Japanese Patent No. 5544078

[0023] [Patent Document 11] Japanese Patent No. 5609569

[0024] Non-patent literature

[0025] [Non-patent document 1] Journal of Photopolymer Science and Technology, Vol. 17, No. 4, p. 587-601 (2004) Summary of the invention

[0026] [Problems to be solved by the invention]

[0027] In response to the recent demand for high resolution of resist patterns, resist compositions using known sulfonium salt-type photoacid generators and quenchers have been unable to sufficiently suppress acid diffusion, resulting in problems such as degradation of lithography performance such as contrast, MEF, and LWR. In addition, there is a problem of pattern collapse due to swelling during fine pattern formation.

[0028] The present invention is made in view of the above-mentioned situation, and its purpose is to provide an onium salt used in a chemically amplified resist composition that has excellent solvent solubility and has excellent lithography performance such as high sensitivity, high contrast, exposure latitude (EL), LWR, etc., especially in optical lithography using high-energy rays such as KrF excimer laser, ArF excimer laser, electron beam (EB), and EUV, as well as a chemically amplified resist composition containing the onium salt and a pattern forming method using the chemically amplified resist composition.

[0029] [Methods to solve the problem]

[0030] The inventors of the present application have repeatedly conducted in-depth studies to achieve the above-mentioned purpose, and have obtained the following insights, and have even completed the present invention: an onium salt containing a sulfonic acid anion having an aromatic ring, wherein the aromatic ring of the anion has a hydroxyl group protected by an acid-labile group and a fluorine-containing substituent, and the onium salt has a structure in which the hydroxyl group and the fluorine-containing substituent are bonded to adjacent carbon atoms, and the onium salt has excellent solvent solubility. A chemically amplified resist composition using the onium salt as a quencher or a photoacid generator has high sensitivity and high contrast, and has excellent EL, LWR and other lithography properties, and is extremely effective in suppressing pattern collapse when fine patterns are formed.

[0031] That is, the present invention provides the following onium salt, chemically amplified resist composition and pattern forming method.

[0032] 1. An onium salt represented by the following formula (1).

[0033] [Chemistry 1]

[0034]

[0035] In the formula, n1 is 0 or 1. n2 is 1, 2 or 3. n3 is 1, 2, 3 or 4. n4 is an integer from 0 to 4. However, when n1 is 0, 2≤n2+n3+n4≤5, and when n1 is 1, 2≤n2+n3+n4≤7.

[0036] R AL It is an acid-labile group.

[0037] R F is a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms. F They can be the same or different.

[0038] R F AND-OR AL Bonded to adjacent carbon atoms.

[0039] L A and L B Each is independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a urethane bond.

[0040] X L It is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom.

[0041] R 1 It is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom.

[0042] R 2 It is a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom other than a fluorine atom.

[0043] Z + It is an onium cation.

[0044] 2. The onium salt according to 1., wherein the acid-labile group is represented by the following formula (AL-1) or (AL-2).

[0045] [Chemistry 2]

[0046]

[0047] In the formula, R L1 , R L2 and R L3Each is independently a hydrocarbon group having 1 to 12 carbon atoms, and a part of -CH2- in the hydrocarbon group may be substituted by -O- or -S-. When the hydrocarbon group contains an aromatic ring, a part or all of the hydrogen atoms in the aromatic ring may be substituted by a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 4 carbon atoms which may also contain a halogen atom, or an alkoxy group having 1 to 4 carbon atoms which may also contain a halogen atom. L1 and R L2 They may be bonded to each other to form a ring, and a part of the -CH2- in the ring may be substituted by -O- or -S-.

[0048] R L4 and R L5 R is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. L6 is a hydrocarbon group having 1 to 20 carbon atoms, and a portion of the -CH2- in the hydrocarbon group may be substituted by -O- or -S-. L5 and R L6 They can also bond to each other and to the carbon atoms to which they are bonded and to L C Together they form a heterocyclic group having 3 to 20 carbon atoms, and a part of the -CH2- in the heterocyclic group may be substituted by -O- or -S-.

[0049] L C It is -O- or -S-.

[0050] m1 is 0 or 1. m2 is 0 or 1.

[0051] * indicates a bond to an adjacent -O- atom.

[0052] 3. The onium salt of 1. or 2., wherein R 2 It is a group represented by the following formula (R2-1) or (R2-2).

[0053] [Chemistry 3]

[0054]

[0055] In the formula, n5 is an integer of 1 to 4. n6 is 0 or 1. n7 is an integer of 0 to 4 when n6 is 0, and is an integer of 0 to 6 when n6 is 1.

[0056] R 3 and R 4 are each independently a hydrogen atom, a halogen atom other than a fluorine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom other than a fluorine atom. 3 and R 4 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring.

[0057] R 5is a halogen atom other than a fluorine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom other than a fluorine atom. 5 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring.

[0058] * indicates respectively and L B and -SO3 - of atomic bonds.

[0059] 4. The onium salt according to any one of 1. to 3., represented by the following formula (1A).

[0060] [Chemistry 4]

[0061]

[0062] In the formula, n1~n4, R AL , R F , L A , X L , R 1 , R 2 and Z + Same as above.

[0063] 5. The onium salt according to any one of 1. to 4., wherein Z + It is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2).

[0064] [Chemistry 5]

[0065]

[0066] In the formula, R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. ct1 and R ct2 They may also bond to each other and to the sulfur atom to which they are bonded to form a ring.

[0067] 6. A chemically amplified resist composition comprising the onium salt according to any one of 1. to 5.

[0068] 7. The chemically amplified resist composition according to 6., comprising a base polymer having a repeating unit represented by the following formula (a1).

[0069] [Chemistry 6]

[0070]

[0071] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0072] X 1 is a single bond, phenylene, naphthylene or *-C(=O)-OX 11 -, and the phenylene group or naphthylene group may be substituted with an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom or a halogen atom. 11 It is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. * represents an atomic bond to a carbon atom of the main chain.

[0073] AL 1 It is an acid-labile group.

[0074] 8. The chemically amplified resist composition according to 7., wherein the base polymer contains a repeating unit represented by the following formula (a2).

[0075] [Chemistry 7]

[0076]

[0077] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0078] X 2 It is a single bond or *-C(=O)-O-. * represents an atomic bond with a carbon atom of the main chain.

[0079] R 11 It is a halogen atom, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl oxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom.

[0080] AL 2 It is an acid-labile group.

[0081] a is an integer from 0 to 4.

[0082] 9. The chemically amplified resist composition according to 7. or 8., wherein the base polymer contains a repeating unit represented by the following formula (b1) or (b2).

[0083] [Chemistry 8]

[0084]

[0085] In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0086] Y 1It is a single bond or *-C(=O)-O-. * represents an atomic bond with a carbon atom of the main chain.

[0087] R 21 It is a group having 1 to 20 carbon atoms, or a structure containing at least one selected from the group consisting of a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-).

[0088] R 22 It is a halogen atom, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain heteroatoms, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain heteroatoms, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain heteroatoms.

[0089] b is an integer from 1 to 4. c is an integer from 0 to 4. However, 1≤b+c≤5.

[0090] 10. A chemically amplified resist composition as described in any one of 7. to 9., wherein the base polymer contains at least one selected from the group consisting of a repeating unit represented by the following formula (c1), a repeating unit represented by the following formula (c2), a repeating unit represented by the following formula (c3) and a repeating unit represented by the following formula (c4).

[0091] [Chemistry 9]

[0092]

[0093] In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0094] Z 1 It is a single bond or a phenylene group.

[0095] Z 2 **-C(=O)-OZ 21 -, **-C(=O)-NH-Z 21 -or**-OZ 21 -.Z 21 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group.

[0096] Z 3 are independently a single bond, a phenylene group, a naphthylene group or *-C(=O)-OZ 31 -.Z 31It is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring.

[0097] Z 4 are independently single bonds, ***-Z 41 -C(=O)-O-、***-C(=O)-NH-Z 41 -or***-OZ 41 -.Z 41 It is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom.

[0098] Z 5 are independently single bonds, ****-Z 51 -C(=O)-O-、****-C(=O)-NH-Z 51 -or****-OZ 51 -.Z 51 It is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom.

[0099] Z 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 61 -, *-C(=O)-N(H)-Z 61 -or*-OZ 61 -.Z 61 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group.

[0100] * indicates an atomic bond to a carbon atom in the main chain. ** indicates an atomic bond to Z 1 Atomic bonds. *** indicates that Z 3 The atomic bond of Z 4 of atomic bonds.

[0101] R 31 and R 32 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 31 and R 32 They may also bond to each other and to the sulfur atom to which they are bonded to form a ring.

[0102] L 1 It is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond.

[0103] R 1 and Rf 2 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0104] R 3 and Rf 4 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0105] R 5 and Rf 6 are independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 5 and Rf 6 It cannot be a hydrogen atom at the same time.

[0106] M - It is a non-nucleophilic relative ion.

[0107] A + It is an onium cation.

[0108] d is an integer from 0 to 3.

[0109] 11. The chemically amplified resist composition according to any one of 6. to 10., further comprising an organic solvent.

[0110] 12. The chemically amplified resist composition according to any one of 6. to 11., wherein the onium salt functions as a quencher.

[0111] 13. The chemically amplified resist composition of 12. further contains an acid generator that generates sulfonic acid, methylated acid, or imidic acid.

[0112] 14. The chemically amplified resist composition according to any one of 6. to 11., wherein the onium salt functions as a photoacid generator.

[0113] 15. The chemically amplified resist composition of 14. further comprises a quencher.

[0114] 16. The chemically amplified resist composition according to any one of 6. to 15., further comprising a surfactant.

[0115] 17. A pattern forming method comprising the following steps:

[0116] Using the chemically amplified resist composition of any one of 6. to 16. to form a resist film on a substrate, exposing the resist film to high energy radiation, and

[0117] The exposed resist film is developed using a developer.

[0118] 18. The pattern forming method according to 17., wherein the high energy ray is KrF excimer laser, ArF excimer laser, EB or EUV with a wavelength of 3 to 15 nm.

[0119] [Effects of the Invention]

[0120] When patterning is performed using a chemically amplified resist composition containing the onium salt of the present invention as a quencher or an acid generator, a resist pattern having high contrast and good sensitivity, excellent lithography performance such as MEF and LWR, and suppressed pattern collapse can be formed. BRIEF DESCRIPTION OF THE DRAWINGS

[0121] [ Figure 1 ] Salt-1 obtained in Example 1-1 1 H-NMR spectrum. DETAILED DESCRIPTION

[0122] [Onium salt]

[0123] The onium salt of the present invention is represented by the following formula (1).

[0124] [Chemistry 10]

[0125]

[0126] In formula (1), n1 is 0 or 1. When n1 is 0, it represents a benzene ring, and when n1 is 1, it represents a naphthalene ring. From the viewpoint of solvent solubility, n1 is preferably 0, i.e., a benzene ring. n2 is 1, 2 or 3. From the viewpoint of raw material scheduling, n2 is preferably 1 or 2, and more preferably 1. n3 is 1, 2, 3 or 4. From the viewpoint of raw material scheduling, n3 is preferably 1 or 2, and more preferably 1. n4 is an integer of 0 to 4. However, when n1 is 0, 2≤n2+n3+n4≤5, and when n1 is 1, 2≤n2+n3+n4≤7.

[0127] In formula (1), R AL The acid-labile group is preferably represented by the following formula (AL-1) or (AL-2).

[0128] [Chemistry 11]

[0129]

[0130] In formula (AL-1), R L1 , R L2 and R L3 Each is independently a hydrocarbon group having 1 to 12 carbon atoms, and a part of -CH2- of the hydrocarbon group may be substituted by -O- or -S-. When the hydrocarbon group contains an aromatic ring, a part or all of the hydrogen atoms of the aromatic ring may be substituted by a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 4 carbon atoms which may also contain a halogen atom, or an alkoxy group having 1 to 4 carbon atoms which may also contain a halogen atom. m1 is 0 or 1. * represents an atomic bond to an adjacent -O-.

[0131] R L1 , R L2and R L3 The hydrocarbon group having 1 to 12 carbon atoms represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include: alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, and n-dodecyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, norbornylmethyl, adamantyl, adamantylmethyl, tricyclo[5.2.1.0 2,6 ]decyl, tetracyclic [6.2.1.1 3,6 .0 2,7 ] Cyclic saturated hydrocarbon groups having 3 to 12 carbon atoms, such as dodecyl; alkenyl groups having 2 to 12 carbon atoms, such as vinyl, allyl, propenyl, butenyl, pentenyl, hexenyl; alkynyl groups having 2 to 12 carbon atoms, such as ethynyl, propynyl, butynyl, pentynyl, hexynyl; cyclic unsaturated aliphatic hydrocarbon groups having 3 to 12 carbon atoms, such as cyclopentenyl and cyclohexenyl; aryl groups having 6 to 12 carbon atoms, such as phenyl, naphthyl, indanyl; aralkyl groups having 7 to 12 carbon atoms, such as benzyl, 1-phenylethyl, 2-phenylethyl: groups obtained by combining these, etc.

[0132] Again, R L1 and R L2 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring, and a portion of the -CH2- in the ring may be substituted by -O- or -S-. Examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a norbornane ring, an adamantane ring, a tricyclic [5.2.1.0 2,6 ]Decane ring, tetracyclic [6.2.1.1 3, 6 .0 2,7 ]Dodecane ring, etc.

[0133] In formula (AL-2), R L4 and R L5 R is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. L4 and R L5 The hydrocarbon group having 1 to 10 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include and are exemplified as R L1 , R L2 and R L3 The same applies to the hydrocarbon groups having 1 to 10 carbon atoms.

[0134] In formula (AL-2), R L6It is a hydrocarbon group having 1 to 20 carbon atoms, and a part of -CH2- of the hydrocarbon group may be substituted by -O- or -S-. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be any of linear, branched, or cyclic. Specific examples thereof include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl and other alkyl groups having 1 to 20 carbon atoms; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, norbornylmethyl, adamantyl, adamantylmethyl, tricyclo[5.2.1.0 2,6 ]decyl, tetracyclic [6.2.1.1 3,6 .0 2,7 ] cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as dodecyl; alkenyl groups having 2 to 20 carbon atoms, such as ethenyl, propenyl, butenyl, pentenyl, and hexenyl; alkynyl groups having 2 to 20 carbon atoms, such as ethynyl, propynyl, butynyl, pentynyl, and hexynyl; cyclic unsaturated aliphatic hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopentenyl, cyclohexenyl, and norbornyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, tolyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, and tert-butylnaphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl and phenethyl; groups obtained by combining them, etc. In addition, R L5 and R L6 They can also bond to each other and to the carbon atoms to which they are bonded and to L C Together they form a heterocyclic group having 3 to 20 carbon atoms, and a part of the -CH2- in the heterocyclic group may be substituted by -O- or -S-.

[0135] In formula (AL-2), L C It is -O- or -S-.

[0136] In formula (AL-2), m2 is 0 or 1. * represents an atomic bond with an adjacent -O-.

[0137] Examples of the acid-labile group represented by the formula (AL-1) include, but are not limited to, the following. In the following formula, * represents an atomic bond with an adjacent -O-.

[0138] [Chemistry 12]

[0139]

[0140] [Chemistry 13]

[0141]

[0142] [Chemistry 14]

[0143]

[0144] [Chemistry 15]

[0145]

[0146] [Chemistry 16]

[0147]

[0148] [Chemistry 17]

[0149]

[0150] [Chemistry 18]

[0151]

[0152] [Chemistry 19]

[0153]

[0154] [Chemistry 20]

[0155]

[0156] [Chemistry 21]

[0157]

[0158] [Chemistry 22]

[0159]

[0160] Examples of the acid-labile group represented by the formula (AL-2) include, but are not limited to, the following. In the following formula, * represents an atomic bond with an adjacent -O-.

[0161] [Chemistry 23]

[0162]

[0163] [Chemistry 24]

[0164]

[0165] In formula (1), R F is a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms. The aforementioned fluorinated saturated hydrocarbon group, fluorinated saturated hydrocarbon oxy group, and fluorinated saturated hydrocarbon thio group are preferably trifluoromethyl, trifluoromethoxy, and trifluoromethylthio groups, respectively. When n3≥2, each R FThey can be the same or different.

[0166] In formula (1), R F AND-OR AL Bonded to adjacent carbon atoms. AL The acidity of the phenol after leaving will be improved, and the solution contrast will be improved.

[0167] In formula (1), L A and L B Each of them is independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a urethane bond. Among them, a single bond, an ether bond or an ester bond is preferred.

[0168] In formula (1), X L It is a single bond or a alkylene group having 1 to 40 carbon atoms which may contain a hetero atom. The alkylene group may be linear, branched or cyclic, and specific examples thereof include alkanediyl and cyclic saturated alkylene groups. The hetero atom may include an oxygen atom, a nitrogen atom, a sulfur atom, etc.

[0169] X L Specific examples of the alkylene group having 1 to 40 carbon atoms which may contain a hetero atom as represented by are shown below, but are not limited thereto. A and L B of atomic bonds.

[0170] [Chemistry 25]

[0171]

[0172] [Chemistry 26]

[0173]

[0174] [Chemistry 27]

[0175]

[0176] [Chemistry 28]

[0177]

[0178] Among them, X L -0~X L -22 and X L -47~X L -58.

[0179] In formula (1), R 1It is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, etc.; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl, etc.; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, hexenyl, etc.; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl, etc.; aryl groups having 2 to 20 carbon atoms, such as phenyl and naphthyl, aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, 2-phenylethyl, etc.; groups obtained by combining these, etc. Among them, aryl groups are preferred. Furthermore, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, and the like.

[0180] In formula (1), R 2 It is a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom other than a fluorine atom. 2 The group represented is preferably represented by the following formula (R2-1) or (R2-2).

[0181] [Chemistry 29]

[0182]

[0183] In formula (R2-1), n5 is an integer of 1 to 4. From the viewpoint of acid diffusion control, n5 is preferably 1 or 2. In formula (R2-2), n6 is 0 or 1. When n6 is 0, it represents a benzene ring, and when n6 is 1, it represents a naphthalene ring. From the viewpoint of solvent solubility, n6 is preferably 0, i.e., a benzene ring. When n6 is 0, n7 is an integer of 0 to 4, and when n6 is 1, it is an integer of 0 to 6.

[0184] In formula (R2-1) and (R2-2), R 3 and R 4 Each of them is independently a hydrogen atom, a halogen atom other than a fluorine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom other than a fluorine atom. Examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and the like. Examples of the hydrocarbon group include and are exemplified as R1 The same examples are given for hydrocarbon groups represented by 3 and R 4 They may also be bonded to each other and to form a ring together with the carbon atoms to which they are bonded. Examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a norbornane ring, an adamantane ring, a tricyclic [5.2.1.0 2,6 ]Decane ring, tetracyclic [6.2.1.1 3,6 .0 2,7 ] dodecane ring, etc. In addition, a part of -CH2- in the aforementioned ring may be substituted by -O- or -S-.

[0185] In formula (R2-2), R 5 is a halogen atom other than a fluorine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom other than a fluorine atom. Examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and the like. Examples of the hydrocarbon group include 1 The same is true for the hydrocarbon groups represented by 5 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring.

[0186] R 2 Specific examples of the alkylene group represented by may be listed below, but are not limited thereto. In the following formula, * represents L B and -SO3 - of atomic bonds.

[0187] [Chemistry 30]

[0188]

[0189] [Chemistry 31]

[0190]

[0191] The onium salt represented by the formula (1) is preferably represented by the following formula (1A).

[0192] [Chemistry 32]

[0193]

[0194] In the formula, n1~n4, R AL , R F , L A , X L , R 1 , R 2 and Z + Same as above.

[0195] The anion of the onium salt represented by formula (1) may be exemplified by the following, but is not limited thereto. F AND-OR AL There is no restriction for adjacent configurations.

[0196] [Chemistry 33]

[0197]

[0198] [Chemistry 34]

[0199]

[0200] [Chemistry 35]

[0201]

[0202] [Chemistry 36]

[0203]

[0204] [Chemistry 37]

[0205]

[0206] [Chemistry 38]

[0207]

[0208] [Chemistry 39]

[0209]

[0210] [Chemistry 40]

[0211]

[0212] [Chemistry 41]

[0213]

[0214] [Chemistry 42]

[0215]

[0216] [Chemistry 43]

[0217]

[0218] [Chemistry 44]

[0219]

[0220] [Chemistry 45]

[0221]

[0222] [Chemistry 46]

[0223]

[0224] [Chemistry 47]

[0225]

[0226] [Chemistry 48]

[0227]

[0228] [Chemistry 49]

[0229]

[0230] [Chemistry 50]

[0231]

[0232] [Chemistry 51]

[0233]

[0234] [Chemistry 52]

[0235]

[0236] [Chemistry 53]

[0237]

[0238] [Chemistry 54]

[0239]

[0240] [Chemistry 55]

[0241]

[0242] [Chemistry 56]

[0243]

[0244] [Chemistry 57]

[0245]

[0246] [Chemistry 58]

[0247]

[0248] [Chemistry 59]

[0249]

[0250] [Chemistry 60]

[0251]

[0252] [Chemistry 61]

[0253]

[0254] [Chemistry 62]

[0255]

[0256] [Chemistry 63]

[0257]

[0258] [Chemistry 64]

[0259]

[0260] [Chemistry 65]

[0261]

[0262] [Chemistry 66]

[0263]

[0264] [Chemistry 67]

[0265]

[0266] [Chemistry 68]

[0267]

[0268] [Chemistry 69]

[0269]

[0270] [Chemistry 70]

[0271]

[0272] [Chemistry 71]

[0273]

[0274] [Chemistry 72]

[0275]

[0276] [Chemistry 73]

[0277]

[0278] [Chemistry 74]

[0279]

[0280] [Chemistry 75]

[0281]

[0282] [Chemistry 76]

[0283]

[0284] [Chemistry 77]

[0285]

[0286] [Chemistry 78]

[0287]

[0288] [Chemistry 79]

[0289]

[0290] [Chemistry 80]

[0291]

[0292] [Chemistry 81]

[0293]

[0294] [Chemistry 82]

[0295]

[0296] [Chemistry 83]

[0297]

[0298] [Chemistry 84]

[0299]

[0300] [Chemistry 85]

[0301]

[0302] [Chemistry 86]

[0303]

[0304] [Chemistry 87]

[0305]

[0306] [Chemistry 88]

[0307]

[0308] [Chemistry 89]

[0309]

[0310] [Chemistry 90]

[0311]

[0312] [Chemistry 91]

[0313]

[0314] [Chemistry 92]

[0315]

[0316] [Chemistry 93]

[0317]

[0318] [Chemistry 94]

[0319]

[0320] [Chemistry 95]

[0321]

[0322] [Chemistry 96]

[0323]

[0324] [Chemistry 97]

[0325]

[0326] [Chemistry 98]

[0327]

[0328] [Chemistry 99]

[0329]

[0330] [Chemical 100]

[0331]

[0332] [Chemistry 101]

[0333]

[0334] [Chemistry 102]

[0335]

[0336] [Chemistry 103]

[0337]

[0338] [Chemistry 104]

[0339]

[0340] [Chemistry 105]

[0341]

[0342] [Chemistry 106]

[0343]

[0344] [Chemistry 107]

[0345]

[0346] [Chemistry 108]

[0347]

[0348] [Chemistry 109]

[0349]

[0350] [Chemistry 110]

[0351]

[0352] [Chemistry 111]

[0353]

[0354] [Chemistry 112]

[0355]

[0356] [Chemistry 113]

[0357]

[0358] [Chemistry 114]

[0359]

[0360] [Chemistry 115]

[0361]

[0362] [Chemistry 116]

[0363]

[0364] [Chemistry 117]

[0365]

[0366] [Chemistry 118]

[0367]

[0368] [Chemistry 119]

[0369]

[0370] [Chemistry 120]

[0371]

[0372] [Chemistry 121]

[0373]

[0374] [Chemistry 122]

[0375]

[0376] [Chemistry 123]

[0377]

[0378] [Chemistry 124]

[0379]

[0380] [Chemistry 125]

[0381]

[0382] [Chemistry 126]

[0383]

[0384] [Chemistry 127]

[0385]

[0386] [Chemistry 128]

[0387]

[0388] [Chemistry 129]

[0389]

[0390] [Chemistry 130]

[0391]

[0392] [Chemistry 131]

[0393]

[0394] [Chemistry 132]

[0395]

[0396] [Chemistry 133]

[0397]

[0398] [Chemistry 134]

[0399]

[0400] [Chemistry 135]

[0401]

[0402] [Chemistry 136]

[0403]

[0404] [Chemistry 137]

[0405]

[0406] [Chemistry 138]

[0407]

[0408] In formula (1), Z + The onium cation is preferably a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2).

[0409] [Chemistry 139]

[0410]

[0411] In formula (cation-1) and (cation-2), R ct1 ~R ct5 Each is independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom.

[0412] R ct1 ~R ct5 Examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0413] R ct1 ~R ct5The hydrocarbon group represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include: alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 30 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 30 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; groups obtained by combining these groups, but aryl groups are preferred. Furthermore, a part of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or the like, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0414] Again, R ct1 and R ct2 They may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. In this case, the structure of the ring may be represented by the following formula.

[0415] [Chemistry 140]

[0416]

[0417] In the formula, the dotted line represents and R ct3 of atomic bonds.

[0418] Examples of the sulfonium cation represented by the formula (cation-1) include the following, but are not limited thereto.

[0419] [Chemistry 141]

[0420]

[0421] [Chemistry 142]

[0422]

[0423] [Chemistry 143]

[0424]

[0425] [Chemistry 144]

[0426]

[0427] [Chemistry 145]

[0428]

[0429] [Chemistry 146]

[0430]

[0431] [Chemistry 147]

[0432]

[0433] [Chemistry 148]

[0434]

[0435] [Chemistry 149]

[0436]

[0437] [Chemistry 150]

[0438]

[0439] [Chemistry 151]

[0440]

[0441] [Chemistry 152]

[0442]

[0443] [Chemistry 153]

[0444]

[0445] [Chemistry 154]

[0446]

[0447] [Chemistry 155]

[0448]

[0449] [Chemistry 156]

[0450]

[0451] [Chemistry 157]

[0452]

[0453] [Chemistry 158]

[0454]

[0455] [Chemistry 159]

[0456]

[0457] [Chemistry 160]

[0458]

[0459] [Chemistry 161]

[0460]

[0461] [Chemistry 162]

[0462]

[0463] [Chemistry 163]

[0464]

[0465] [Chemistry 164]

[0466]

[0467] [Chemistry 165]

[0468]

[0469] [Chemistry 166]

[0470]

[0471] [Chemistry 167]

[0472]

[0473] Specific examples of the iodonium cation represented by the formula (cation-2) include those shown below, but are not limited thereto.

[0474] [Chemistry 168]

[0475]

[0476] [Chemistry 169]

[0477]

[0478] Specific examples of the onium salt of the present invention include any combination of the above-mentioned anions and cations.

[0479] The onium salt of the present invention can be synthesized by a known method. As an example, a method for producing an onium salt represented by the following formula (PAG-1-ex) will be described.

[0480] [Chemistry 170]

[0481]

[0482] In the formula, R AL , R F , R 1 , R 2 , n1~n4 and Z + Same as above. X Hal M is a chlorine atom, a bromine atom or an iodine atom. + For the cation. - For the anion.

[0483] The first step is to prepare a Grignard reagent from a commercially available product or a synthesizable raw material SM-1 using a known synthesis method, and react with carbon dioxide (dry ice) to obtain an intermediate In-1. The reaction can be carried out using a known organic synthesis method. Specifically, magnesium metal is suspended in an ether solvent such as diethyl ether or tetrahydrofuran (THF), and a dilute solution consisting of the raw material SM-1 and the solvent used is added dropwise to prepare the Grignard reagent. X of the raw material SM-1 Hal When X is a bromine atom or an iodine atom, an activator of magnesium metal is not necessary, but Hal When it is a chlorine atom, the Grignard reagent can be smoothly prepared by using a small amount of 1,2-dibromoethane and iodine as an activating agent. The reaction temperature is carried out at room temperature to about the boiling point of the solvent used. After the Grignard reagent is prepared, dry ice is suspended in the solvent used for preparation, and the Grignard reagent is added dropwise. The reaction time is ideal from the perspective of yield if the reaction is tracked by silica gel thin layer chromatography (TLC) and the reaction is completed, usually about 5 to 30 minutes. Thereafter, the magnesium salt is dissolved using dilute hydrochloric acid or the like, and the target is extracted from the reaction mixture, and a conventional aqueous work-up is performed to obtain the intermediate In-1. The intermediate In-1 obtained can be purified by conventional methods such as chromatography and recrystallization if necessary.

[0484] The second step is a step of obtaining the intermediate In-2 by reacting the intermediate In-1 with the raw material SM-2. When the carboxyl group of the intermediate In-1 and the hydroxyl group of the raw material SM-2 directly form an ester bond, various condensing agents can be used. The condensing agent used can be listed as: N, N'-dicyclohexylcarbodiimide, N, N'-diisopropylcarbodiimide, 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide, hydrochloric acid-1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, etc. Considering the viewpoint that the urea compound generated as a by-product is easily removed after the reaction, hydrochloric acid-1-ethyl-3-(3-dimethylaminopropyl)carbodiimide is preferably used. The reaction is carried out by dissolving the intermediate In-1 and the raw material SM-2 in a halogen-based solvent such as dichloromethane and adding a condensing agent. If 4-dimethylaminopyridine (DMAP) is added as a catalyst, the reaction rate can be improved. The reaction time is ideal from the viewpoint of yield, if the reaction is tracked by TLC and the reaction is completed, usually about 12 to 24 hours. After stopping the reaction, the by-product urea compound is filtered or washed with water as needed, and the reaction solution is subjected to a conventional aqueous work-up to obtain the intermediate In-2. The intermediate In-2 obtained can be purified by conventional methods such as chromatography and recrystallization if necessary.

[0485] The third step is to make the intermediate In-2 and Z + X - The step of exchanging the onium salt represented by X to obtain an onium salt (PAG-1-ex). - Considering the fact that the exchange reaction is easy to carry out quantitatively, chloride ion, bromide ion, iodide ion or methylsulfate anion is preferred. If the progress of the reaction is confirmed by TLC, it is more ideal from the perspective of yield. The onium salt (PAG-1-ex) can be obtained from the reaction mixture by conventional aqueous work-up. If necessary, it can be purified by conventional methods such as chromatography and recrystallization.

[0486] In the above process, the ion exchange in the third step can be easily carried out by a known method, for example, refer to Japanese Patent Application Laid-Open No. 2007-145797.

[0487] In addition, the above-mentioned production method is only an example at best, and the production method of the onium salt of the present invention is not limited to this.

[0488] As for the structural characteristics of the onium salt of the present invention, acid-labile groups and fluorine-containing substituents having hydroxyl groups bonded to the aromatic ring of the anion can be cited, and they are bonded to adjacent carbon atoms. The acid-labile groups of the exposed part will cause a deprotection reaction due to the generated acid, and produce aromatic hydroxyl groups. Thereby, the contrast between the exposed part and the unexposed part will be improved. In addition, the adjacent fluorine-containing substituents will improve the solvent solubility of the sulfonium salt itself, and at the same time, the acidity of the aromatic hydroxyl groups generated in the exposed part will be improved due to its electron-withdrawing property. When the resist film is developed with an alkaline developer after exposure, the affinity of the generated aromatic hydroxyl groups with the alkaline developer will be improved, and the exposed part will be effectively removed by the developer. In addition, it is believed that the aromatic hydroxyl groups adjacent to the fluorine-containing substituents will not attract the alkaline developer to the unexposed part more than the carboxyl group due to the water-repellent effect of the fluorine atom, and have the effect of reducing the swelling caused by the alkaline developer. By this, the collapse of the resist pattern generated in the unexposed part is suppressed. By utilizing their synergistic effect, when using the onium salt of the present invention, a pattern with high dissolution contrast, excellent LWR of the line pattern and CDU of the hole pattern, and resistance to pattern collapse can be formed, so it is suitable as a positive resist composition.

[0489] The onium salt of the present invention can be ideally used as a photoacid generator or quencher. In addition, in the present invention, the photoacid generator is a compound that generates a strong acid due to high-energy radiation, and the strong acid is a compound having an acidity sufficient to cause a deprotection reaction of an acid-labile group. The quencher is a material used to capture the strong acid generated from the photoacid generator and thereby prevent it from diffusing toward the unexposed portion to form a desired pattern. The aforementioned onium salt will generate an alkanesulfonic acid or an aromatic sulfonic acid due to light exposure, but because it has a strong alkalinity of sulfonium or iodonium, it can also function as a quencher. When the acid-labile group of the aforementioned alkanesulfonic acid or aromatic sulfonic acid is a tertiary ester or tertiary ether, it does not have an acidity that causes a deprotection reaction. Therefore, in order to cause a deprotection reaction of an acid-labile group, as described later, it is effective to add an acid generator that generates a fluorinated sulfonic acid, an imidic acid, or a methylated acid at the α position that acts as a strong acid. The acid generator that generates the sulfonic acid, imidic acid or methylated acid in which the α-position is fluorinated may be of an added type or of a bonded type that is bonded to the base polymer.

[0490] If the above-mentioned onium salt that generates alkanesulfonic acid or aromatic sulfonic acid and the acid generator that generates super-strong acid perfluoroalkyl sulfonic acid are mixed and irradiated, alkanesulfonic acid or aromatic sulfonic acid and perfluoroalkyl sulfonic acid will be generated. The acid generator is not completely decomposed, so there is an undecomposed acid generator nearby. Here, if the onium salt that generates alkanesulfonic acid or aromatic sulfonic acid coexists with perfluoroalkyl sulfonic acid, the perfluoroalkyl sulfonic acid will initially cause ion exchange with the onium salt that generates alkanesulfonic acid or aromatic sulfonic acid, and perfluoroalkyl sulfonic acid onium salt will be generated, and alkanesulfonic acid or aromatic sulfonic acid will be released. The reason is that perfluoroalkyl sulfonic acid salts with high acid strength are relatively stable. On the other hand, even if the onium salt of perfluoroalkyl sulfonic acid and alkanesulfonic acid or aromatic sulfonic acid exist, ion exchange will not occur. Similar ion exchange occurs not only in perfluoroalkylsulfonic acid but also in arylsulfonic acid, alkylsulfonic acid, imidic acid, methylated acid, etc., which have higher acid strength than the sulfonic acid generated from the onium salt of the present invention.

[0491] When the onium salt functions as a quencher, the resist composition of the present invention may contain other sulfonium salts or iodonium salts as quenchers. In this case, the sulfonium salts or iodonium salts added as quenchers are preferably sulfonium salts or iodonium salts of carboxylic acids, sulfonic acids, imidic acids, saccharin, etc. In this case, the α-position of the carboxylic acid may or may not be fluorinated.

[0492] When the acid-labile group of the base polymer is an acetal group or a tertiary ester group with high acid-leaving reactivity, the sulfonic acid generated from the onium salt of the present invention causes a deprotection reaction of such an acid-labile group. In this case, the onium salt of the present invention functions not as a quencher but as an acid generator. In this case, the resist composition of the present invention preferably contains a sulfonium salt or an iodonium salt as a quencher that generates an acid with a weaker acid strength than the sulfonic acid generated from the onium salt of the present invention.

[0493] [Chemically amplified resist composition]

[0494] [(A) Onium salt]

[0495] The chemically amplified resist composition of the present invention contains (A) an onium salt represented by formula (1) as an essential component. In the chemically amplified resist composition of the present invention, the onium salt of component (A) can function as an acid generator as described above, and can also function as a quencher.

[0496] In the chemically amplified resist composition of the present invention, the content of the onium salt represented by formula (1) of component (A) is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 30 parts by mass, relative to 80 parts by mass of the base polymer described later. If the content of component (A) is within the above range, the sensitivity and resolution are good, and there is no problem of foreign matter generated after the development or peeling of the resist film, so it is more ideal. The onium salt of component (A) can be used alone or in combination of two or more.

[0497] [(B) Base polymer]

[0498] The chemically amplified resist composition of the present invention may contain a base polymer as the component (B). The base polymer (B) contains a repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1).

[0499] [Chemistry 171]

[0500]

[0501] In formula (a1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0502] In formula (a1), X 1 is a single bond, phenylene, naphthylene or *-C(=O)-OX 11 -, and the phenylene group or naphthylene group may be substituted with an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom or a halogen atom. 11 It is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. * represents an atomic bond to a carbon atom of the main chain.

[0503] In formula (a1), AL 1 The acid-labile group is an acid-labile group. Examples of the acid-labile group include those described in JP-A-2013-80033 and JP-A-2013-83821.

[0504] Representative examples of the acid-labile group include those represented by the following formulae (AL-3) to (AL-5).

[0505] [Chemistry 172]

[0506]

[0507] In the formula, the dotted lines represent atomic bonds.

[0508] In formula (AL-3) and (AL-4), R L1 and R L2 Each of the above hydrocarbon groups is independently a hydrocarbon group having 1 to 40 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The above hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. The above hydrocarbon group preferably has 1 to 20 carbon atoms.

[0509] In the formula (AL-3), k is an integer of 0-10, preferably an integer of 1-5.

[0510] In formula (AL-4), R L3 and RL4 Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. L2 , R L3 and R L4 Any two of them may be bonded to each other and together with the carbon atom or the carbon atom and oxygen atom to which they are bonded form a ring having 3 to 20 carbon atoms. The aforementioned ring is preferably a ring having 4 to 16 carbon atoms, and is particularly preferably an alicyclic ring.

[0511] In formula (AL-5), R L5 , R L6 and R L7 Each is independently a hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. L5 , R L6 and R L7 Any two of them may be bonded to each other and together with the carbon atoms to which they are bonded form a ring having 3 to 20 carbon atoms. The aforementioned ring is preferably a ring having 4 to 16 carbon atoms, and is particularly preferably an alicyclic ring.

[0512] Specific examples of the repeating unit a1 include those shown below, but are not limited thereto. A and AL 1 Same as above.

[0513] [Chemistry 173]

[0514]

[0515] [Chemistry 174]

[0516]

[0517] [Chemistry 175]

[0518]

[0519] The base polymer may further contain a repeating unit represented by the following formula (a2) (hereinafter also referred to as repeating unit a2).

[0520] [Chemistry 176]

[0521]

[0522] In formula (a2), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 2It is a single bond or *-C(=O)-O-. * indicates an atomic bond with a carbon atom of the main chain. 11 It is a halogen atom, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl oxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom. 2 The acid-labile group can be exemplified by AL 1 The same examples are given for the acid-labile groups represented by a. a is an integer of 0 to 4, preferably 0 or 1.

[0523] Specific examples of repeating unit a2 include those shown below, but are not limited thereto. A and AL 2 Same as above.

[0524] [Chemistry 177]

[0525]

[0526] The base polymer preferably further contains a repeating unit represented by the following formula (b1) (hereinafter also referred to as repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit b2).

[0527] [Chemistry 178]

[0528]

[0529] In formula (b1) and (b2), R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 It is a single bond or *-C(=O)-O-. * indicates an atomic bond with a carbon atom of the main chain. 21 It is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one structure selected from the group consisting of a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-). 22 is a halogen atom, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl oxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom. b is an integer of 1 to 4. c is an integer of 0 to 4. However, 1≤b+c≤5.

[0530] Specific examples of the repeating unit b1 include those shown below, but are not limited thereto. A Same as above.

[0531] [Chemistry 179]

[0532]

[0533] [Chemistry 180]

[0534]

[0535] [Chemistry 181]

[0536]

[0537] [Chemistry 182]

[0538]

[0539] [Chemistry 183]

[0540]

[0541] [Chemistry 184]

[0542]

[0543] [Chemistry 185]

[0544]

[0545] [Chemistry 186]

[0546]

[0547] [Chemistry 187]

[0548]

[0549] [Chemistry 188]

[0550]

[0551] [Chemistry 189]

[0552]

[0553] [Chemistry 190]

[0554]

[0555] [Chemistry 191]

[0556]

[0557] [Chemistry 192]

[0558]

[0559] [Chemistry 193]

[0560]

[0561] [Chemistry 194]

[0562]

[0563] Specific examples of the repeating unit b2 include those shown below, but are not limited thereto. A Same as above.

[0564] [Chemistry 195]

[0565]

[0566] [Chemistry 196]

[0567]

[0568] [Chemistry 197]

[0569]

[0570] [Chemistry 198]

[0571]

[0572] [Chemistry 199]

[0573]

[0574] The repeating unit b1 or b2 is preferably one having a lactone ring as a polar group in ArF lithography, and preferably one having a phenol moiety in KrF lithography, EB lithography, and EUV lithography.

[0575] The aforementioned base polymer may further contain at least one selected from the repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit c1), the repeating unit represented by the following formula (c2) (hereinafter also referred to as repeating unit c2), the repeating unit represented by the following formula (c3) (hereinafter also referred to as repeating unit c3) and the repeating unit represented by the following formula (c4) (hereinafter also referred to as repeating unit c4).

[0576] [Chemistry 200]

[0577]

[0578] In formulas (c1) to (c4), R Aare independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 is a single bond or a phenylene group. 2 **-C(=O)-OZ 21 -, **-C(=O)-NH-Z 21 -or**-OZ 21 -.Z 21 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 3 are independently a single bond, a phenylene group, a naphthylene group or *-C(=O)-OZ 31 -.Z 31 Z is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. 4 are independently single bonds, ***-Z 41 -C(=O)-O-、***-C(=O)-NH-Z 41 -or***-OZ 41 -.Z 41 Z is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 5 are independently single bonds, ****-Z 51 -C(=O)-O-、****-C(=O)-NH-Z 51 -or****-OZ 51 -.Z 51 Z is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 61 -, *-C(=O)-N(H)-Z 61 -or*-OZ 61 -.Z 61 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group. * indicates an atomic bond with a carbon atom of the main chain. ** indicates an atomic bond with Z 1 Atomic bonds. *** indicates that Z 3 The atomic bond of Z 4 of atomic bonds.

[0579] Z 21 , Z 31 and Z 61The aliphatic alkylene group represented may be any of straight chain, branched or cyclic, and specific examples thereof include alkanediyl groups such as methane-1,1-diyl, ethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-2,2-diyl, butane-1,1-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-2,3-diyl, butane-1,4-diyl, 1,1-dimethylethane-1,2-diyl, pentane-1,5-diyl, 2-methylbutane-1,2-diyl and hexane-1,6-diyl; cycloalkanediyl groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl and cyclohexanediyl; and groups obtained by combining these groups.

[0580] Z 41 and Z 51 The alkylene group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those shown below, but are not limited thereto.

[0581] [Chemistry 201]

[0582]

[0583] In the formula, the dotted lines represent atomic bonds.

[0584] In formula (c1), R 31 and R 32 Each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these, but aryl groups are preferably used. Furthermore, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0585] Again, R 31 and R 32 They may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. In this case, the ring may be exemplified as R in the description of formula (cation-1): ct1 and R ct2 The same example is true of the rings that can be formed when they are bonded to the sulfur atoms to which they are bonded.

[0586] The cation of the repeating unit c1 may be exemplified by the following, but is not limited thereto. A Same as above.

[0587] [Chemistry 202]

[0588]

[0589] [Chemistry 203]

[0590]

[0591] [Chemistry 204]

[0592]

[0593] [Chemistry 205]

[0594]

[0595] [Chemistry 206]

[0596]

[0597] [Chemistry 207]

[0598]

[0599] [Chemistry 208]

[0600]

[0601] In formula (c1), M -It is a non-nucleophilic relative ion. The aforementioned non-nucleophilic relative ion is preferably a halide ion, a sulfonic acid anion, an imidic acid anion and a methylated acid anion. Specific examples of the aforementioned halide ion include chloride ion, bromide ion, etc. Specific examples of the aforementioned sulfonic acid anion (sulfonate ion) include fluoroalkylsulfonate ions such as trifluoromethanesulfonate ion, 1,1,1-trifluoroethanesulfonate ion, nonafluorobutanesulfonate ion; arylsulfonate ions such as toluenesulfonate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as methanesulfonate ion and butanesulfonate ion, etc. Specific examples of the imidic acid anion (imide ion) include bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, bis(perfluorobutylsulfonyl)imide ion, etc. Specific examples of the methide acid anion (methide ion) include tris(trifluoromethylsulfonyl)methide ion, tris(perfluoroethylsulfonyl)methide ion, etc.

[0602] Other examples of the non-nucleophilic counter ion include an anion represented by any one of the following formulae (c1-1) to (c1-4).

[0603] [Chemistry 209]

[0604]

[0605] In formula (c1-1), R fa is a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be straight chain, branched, or cyclic. Specific examples thereof include those exemplified below as R in formula (c1-1-1): fa1 The same examples are given for the hydrocarbon groups represented.

[0606] The anion represented by the formula (c1-1) is preferably represented by the following formula (c1-1-1).

[0607] [Chemistry 210]

[0608]

[0609] In formula (c1-1-1), Q 1 and Q 2 Each of them is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. In order to improve solvent solubility, at least one of them is preferably a trifluoromethyl group. m is an integer of 0 to 4, and is particularly preferably 1. fa1The hydrocarbon group may contain a hetero atom and has 1 to 35 carbon atoms. The hetero atom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and is more preferably an oxygen atom. The hydrocarbon group is particularly preferably a hydrocarbon group having 6 to 30 carbon atoms from the viewpoint of obtaining a high resolution when forming a fine pattern.

[0610] In formula (c1-1-1), R fa1 The hydrocarbon group having 1 to 35 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: alkyl groups having 1 to 35 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and eicosyl; cyclic saturated hydrocarbon groups having 3 to 35 carbon atoms, such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated aliphatic hydrocarbon groups having 2 to 35 carbon atoms, such as allyl and 3-cyclohexenyl; aryl groups having 6 to 35 carbon atoms, such as phenyl, 1-naphthyl, 2-naphthyl, and 9-fluorenyl; aralkyl groups having 7 to 35 carbon atoms, such as benzyl and diphenylmethyl; groups obtained by combining these.

[0611] Furthermore, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Examples of the hydrocarbon group containing a hetero atom include a tetrahydrofuranyl group, a methoxymethyl group, an ethoxymethyl group, a methylthiomethyl group, an acetamidomethyl group, a trifluoroethyl group, a (2-methoxyethoxy)methyl group, an acetoxymethyl group, a 2-carboxy-1-cyclohexyl group, a 2-oxopropyl group, a 4-oxo-1-adamantyl group, and a 3-oxocyclohexyl group.

[0612] In formula (c1-1-1), L a1 It is a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond. From the viewpoint of synthesis, it is preferably an ether bond or an ester bond, and more preferably an ester bond.

[0613] The anions represented by formula (c1-1) include, but are not limited to, the following. 1 As mentioned above, Ac is acetyl.

[0614] [Chemistry 211]

[0615]

[0616] [Chemistry 212]

[0617]

[0618] [Chemistry 213]

[0619]

[0620] [Chemistry 214]

[0621]

[0622] [Chemistry 215]

[0623]

[0624] [Chemistry 216]

[0625]

[0626] [Chemistry 217]

[0627]

[0628] [Chemistry 218]

[0629]

[0630] [Chemistry 219]

[0631]

[0632] [Chemistry 220]

[0633]

[0634] In formula (c1-2), R fb1 and R fb2 Each is independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The same examples are given for hydrocarbon groups. fb1 and R fb2 It is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 They can also bond to each other and to the groups to which they are bonded (-CF2-SO2-N - -SO2-CF2-) together to form a ring, at this time, R fb1 and Rfb2 The groups obtainable by mutual bonding are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0635] In formula (c1-3), R fc1 , R fc2 and R fc3 Each is independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The same examples are given for hydrocarbon groups. fc1 , R fc2 and R fc3 It is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 They can also bond to each other and to the groups to which they are bonded (-CF2-SO2-C - -SO2-CF2-) together to form a ring, at this time, R fc1 and R fc2 The groups obtainable by mutual bonding are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0636] In formula (c1-4), R fd is a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The same examples are given for the hydrocarbon groups represented.

[0637] Examples of the anion represented by the formula (c1-4) include the following, but are not limited thereto.

[0638] [Chemistry 221]

[0639]

[0640] [Chemistry 222]

[0641]

[0642] Examples of the non-nucleophilic counter ion include anions having an aromatic ring substituted with an iodine atom or a bromine atom. Specific examples of such anions include those represented by the following formula (c1-5).

[0643] [Chemistry 223]

[0644]

[0645] In formula (c1-5), x is an integer satisfying 1≤x≤3. y and z are integers satisfying 1≤y≤5, 0≤z≤3 and 1≤y+z≤5. y is preferably an integer satisfying 1≤y≤3, more preferably 2 or 3. z is preferably an integer satisfying 0≤z≤2.

[0646] In formula (c1-5), X BI is an iodine atom or a bromine atom. When x and / or y is 2 or more, they may be the same as or different from each other.

[0647] In formula (c1-5), L 1 It is a saturated alkylene group having 1 to 6 carbon atoms which may contain a single bond, an ether bond or an ester bond. The saturated alkylene group may be linear, branched or cyclic.

[0648] In formula (c1-5), L 2 When x is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms. When x is 2 or 3, it is a (x+1)-valent linking group having 1 to 20 carbon atoms. The linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.

[0649] In formula (c1-5), R fe is a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon oxy group having 1 to 20 carbon atoms, a hydrocarbon carbonyl group having 2 to 20 carbon atoms, a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms or a hydrocarbon sulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group or an ether bond, or -N(R feA )(R feB )、-N(R feC )-C(=O)-R feD or -N(R feC )-C(=O)-OR feD . R feA and R feB R is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. feC R is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl oxy group having 2 to 6 carbon atoms. feDIt is an aliphatic hydrocarbon group having 1 to 16 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. The aforementioned hydrocarbon group, hydrocarbon oxy group, hydrocarbon carbonyl group, hydrocarbon oxycarbonyl group, hydrocarbon carbonyloxy group, and hydrocarbon sulfonyloxy group may be straight-chain, branched, or cyclic. When x and / or z is 2 or more, each R fe They can be the same or different.

[0650] Among them, R fe Preferably, it is hydroxyl, -N(R feC )-C(=O)-R feD 、-N(R feC )-C(=O)-OR feD , fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group and the like.

[0651] In formula (c1-5), Rf 11 ~Rf 14 are independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them is a fluorine atom or a trifluoromethyl group. 11 With Rf 12 They can also be combined to form a carbonyl group. 13 and Rf 14 Preferably, they are all fluorine atoms.

[0652] The anions represented by formula (c1-5) include, but are not limited to, the following. BI Same as above.

[0653] [Chemistry 224]

[0654]

[0655] [Chemistry 225]

[0656]

[0657] [Chemistry 226]

[0658]

[0659] [Chemistry 227]

[0660]

[0661] [Chemistry 228]

[0662]

[0663] [Chemistry 229]

[0664]

[0665] [Chemistry 230]

[0666]

[0667] [Chemistry 231]

[0668]

[0669] [Chemistry 232]

[0670]

[0671] [Chemistry 233]

[0672]

[0673] [Chemistry 234]

[0674]

[0675] [Chemistry 235]

[0676]

[0677] [Chemistry 236]

[0678]

[0679] [Chemistry 237]

[0680]

[0681] [Chemistry 238]

[0682]

[0683] [Chemistry 239]

[0684]

[0685] [Chemistry 240]

[0686]

[0687] [Chemistry 241]

[0688]

[0689] [Chemistry 242]

[0690]

[0691] [Chemistry 243]

[0692]

[0693] [Chemistry 244]

[0694]

[0695] [Chemistry 245]

[0696]

[0697] [Chemistry 246]

[0698]

[0699] The aforementioned non-nucleophilic counter ion can also use a fluorobenzenesulfonic acid anion bonded to an aromatic group containing an iodine atom described in Japanese Patent No. 6648726, an anion having a mechanism of decomposition by acid described in International Publication No. 2021 / 200056 or Japanese Patent Application Publication No. 2021-70692, an anion having a cyclic ether group described in Japanese Patent Application Publication No. 2018-180525 or Japanese Patent Application Publication No. 2021-35935, and an anion described in Japanese Patent Application Publication No. 2018-92159.

[0700] The aforementioned non-nucleophilic counter ions may further use anions of bulky benzenesulfonic acid derivatives containing no fluorine atoms as described in Japanese Patent Publication Nos. 2006-276759, 2015-117200, 2016-65016, and 2019-202974, and benzenesulfonic acid anions containing no fluorine atoms and bonded to an aromatic group containing an iodine atom as described in Japanese Patent No. 6645464, and alkylsulfonic acid anions.

[0701] The non-nucleophilic counter ion may also be an anion of a disulfonic acid as described in Japanese Patent Application Publication No. 2015-206932, an anion having a sulfonic acid on one side and a sulfonamide or sulfonylimide different therefrom on the other side as described in International Publication No. 2020 / 158366, or an anion having a sulfonic acid on one side and a carboxylic acid on the other side as described in Japanese Patent Application Publication No. 2015-24989.

[0702] In formula (c2) and (c3), L 1 It is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond. Among them, from the viewpoint of synthesis, an ether bond, an ester bond or a carbonyl group is preferred, and an ester bond or a carbonyl group is more preferred.

[0703] In formula (c2), Rf1 and Rf 2 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 1 and Rf 2 In order to increase the acid strength of the generated acid, it is preferred that all of them are fluorine atoms. 3 and Rf 4 Each of them is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 3 and Rf 4 At least one of them is preferably trifluoromethyl.

[0704] In formula (c3), Rf 5 and Rf 6 are independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 5 and Rf 6 They cannot be hydrogen atoms at the same time. Among them, in order to improve solvent solubility, Rf 5 and Rf 6 At least one of them is preferably trifluoromethyl.

[0705] In formulae (c2) and (c3), d is an integer of 0 to 3, preferably 1.

[0706] Specific examples of the anion of the repeating unit c2 include those shown below, but are not limited thereto. A Same as above.

[0707] [Chemistry 247]

[0708]

[0709] [Chemistry 248]

[0710]

[0711] [Chemistry 249]

[0712]

[0713] [Chemistry 250]

[0714]

[0715] [Chemistry 251]

[0716]

[0717] [Chemistry 252]

[0718]

[0719] [Chemistry 253]

[0720]

[0721] Specific examples of the anion of the repeating unit c3 include those shown below, but are not limited thereto. A Same as above.

[0722] [Chemistry 254]

[0723]

[0724] [Chemistry 255]

[0725]

[0726] [Chemistry 256]

[0727]

[0728] [Chemistry 257]

[0729]

[0730] [Chemistry 258]

[0731]

[0732] [Chemistry 259]

[0733]

[0734] [Chemistry 260]

[0735]

[0736] Specific examples of anions of the repeating unit represented by formula (c4) include those shown below, but are not limited thereto. A Same as above.

[0737] [Chemistry 261]

[0738]

[0739] In formulas (c2) to (c4), A + It is an onium cation. The onium cations include ammonium cations, sulfonium cations, and iodonium cations, preferably sulfonium cations and iodonium cations. Specific examples thereof include the same examples as those exemplified as the sulfonium cations represented by formula (cation-1) and the iodonium cations represented by formula (cation-2), or the same examples as those exemplified as the ammonium cations represented by formula (cation-3) described later, but are not limited thereto.

[0740] As specific structures of the repeating units c1 to c4, any combination of the above-mentioned anions and cations can be mentioned.

[0741] Among repeating units c1 to c4, repeating units c2, c3 and c4 are preferred from the viewpoint of controlling acid diffusion, repeating units c2 and c4 are more preferred from the viewpoint of acid strength of the generated acid, and repeating unit c2 is more preferred from the viewpoint of solvent solubility.

[0742] The base polymer may further contain a repeating unit having a structure in which a hydroxyl group is protected by an acid-labile group (hereinafter also referred to as repeating unit d). As for the repeating unit d, if it is a structure in which one or more hydroxyl groups are protected, and the protecting group can be decomposed by the action of an acid to generate a hydroxyl group, there is no particular limitation, and it is preferably represented by the following formula (d1).

[0743] [Chemistry 262]

[0744]

[0745] In formula (d1), R A Same as above. 41 It is a (e+1)-valent hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. 42 is an acid-labile group. e is an integer of 1-4.

[0746] In formula (d1), R 42 The acid-labile group represented by R may be any one that is deprotected by the action of an acid to generate a hydroxyl group. 42 The structure of is not particularly limited, and is preferably an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (d2), and is particularly preferably an alkoxymethyl group represented by the following formula (d2).

[0747] [Chemistry 263]

[0748]

[0749] In the formula, * represents an atomic bond. 43 It is a hydrocarbon group having 1 to 15 carbon atoms.

[0750] R 42 Specific examples of the acid-labile group represented by the formula (d2), the alkoxymethyl group represented by the formula (d2), and the repeating unit d include the same examples as those exemplified in the description of the repeating unit d described in JP-A-2020-111564.

[0751] The base polymer may further contain a repeating unit e derived from indene, benzofuran, benzothiophene, acenaphthene, chromone, coumarin, norbornadiene or a derivative thereof. Specific examples of the monomer providing the repeating unit e include the following, but are not limited thereto.

[0752] [Chemical 264]

[0753]

[0754] The aforementioned base polymer may further contain repeating unit f derived from indene, vinylpyridine or vinylcarbazole.

[0755] In the polymer of the present invention, the content ratios of repeating units a1, a2, b1, b2, c1 to c4, d, e and f are preferably 0 < a1 ≤ 0.8, 0 ≤ a2 ≤ 0.8, 0 ≤ b1 ≤ 0.6, 0 ≤ b2 ≤ 0.6, 0 ≤ c1 ≤ 0.4, 0 ≤ c2 ≤ 0.4, 0 ≤ c3 ≤ 0.4, 0 ≤ c4 ≤ 0.4, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.3 and 0 ≤ f ≤ 0.3, and more preferably 0 < a1 ≤ 0.7, 0 ≤ a2 ≤ 0.7, 0 ≤ b1 ≤ 0.5, 0 ≤ b2 ≤ 0.5, 0 ≤ c1 ≤ 0.3, 0 ≤ c2 ≤ 0.3, 0 ≤ c3 ≤ 0.3, 0 ≤ c4 ≤ 0.3, 0 ≤ d ≤ 0.3, 0 ≤ e ≤ 0.3 and 0 ≤ f ≤ 0.3.

[0756] The weight average molecular weight (Mw) of the aforementioned polymer is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no concern about a decrease in resolution caused by the inability to ensure the difference in dissolution rate before and after exposure. In addition, in the present invention, Mw is a polystyrene conversion measurement value obtained by gel permeation chromatography (GPC) using THF or N,N-dimethylformamide (DMF) as a solvent.

[0757] In addition, regarding the molecular weight distribution (Mw / Mn) of the aforementioned polymer, as the pattern rule is miniaturized, the influence of Mw / Mn tends to become larger. Therefore, in order to obtain a resist composition that can be ideally used for fine pattern sizes, Mw / Mn is preferably a narrow distribution of 1.0 to 2.0. If it is within the above range, there are few low molecular weight and high molecular weight polymers, and there is no concern about observing foreign substances on the pattern or deterioration of the pattern shape after exposure.

[0758] When synthesizing the aforementioned polymer, for example, monomers providing the aforementioned repeating units may be added with a radical polymerization initiator in an organic solvent and heated to carry out polymerization.

[0759] The organic solvent used in the polymerization can be exemplified by toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), etc. The above-mentioned polymerization initiator can be exemplified by 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, etc. The amount of these initiators added is preferably 0.01 to 25 mol% relative to the total amount of the monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, and more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the perspective of production efficiency.

[0760] The polymerization initiator can be added to the monomer solution and supplied to the reactor, or an initiator solution different from the monomer solution can be prepared and supplied to the reactor separately. Since there is a possibility that the polymerization reaction will proceed and an ultra-high molecular weight polymer will be generated due to the free radicals generated from the initiator during the standby time, the monomer solution and the initiator solution should be prepared separately and added dropwise from the perspective of quality management. The acid-labile group can be directly introduced into the monomer, or it can be protected or partially protected after polymerization. In addition, in order to adjust the molecular weight, a known chain transfer agent such as dodecyl mercaptan and 2-mercaptoethanol can also be used in combination. At this time, the amount of these chain transfer agents added is preferably 0.01 to 20 mol% relative to the total amount of the monomers to be polymerized.

[0761] In the case of a monomer containing a hydroxyl group, the hydroxyl group may be replaced with an acetal group such as ethoxyethoxy which is easily deprotected by an acid during polymerization, and then deprotected using a weak acid and water after polymerization. Alternatively, the hydroxyl group may be replaced with an acetyl group, a formyl group, a pivaloyl group, etc., and then hydrolyzed with an alkali after polymerization.

[0762] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers may be added with a free radical polymerization initiator in an organic solvent and subjected to heat polymerization. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene may be used, and after polymerization, the acetoxy group may be deprotected by alkaline hydrolysis to obtain polyhydroxystyrene or hydroxyvinylnaphthalene.

[0763] The base used in the alkaline hydrolysis may be aqueous ammonia, triethylamine, etc. The reaction temperature is preferably -20 to 100°C, more preferably 0 to 60°C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0764] The amount of each monomer in the monomer solution may be appropriately set, for example, so as to achieve a desired content ratio of the repeating unit.

[0765] As for the polymer obtained by the above-mentioned production method, the reaction solution obtained by the polymerization reaction can be used as the final product, and the powder obtained by the purification step such as the reprecipitation method of adding the polymerization solution to a poor solvent to obtain the powder can also be handled as the final product. From the perspective of operating efficiency and quality stabilization, it is preferable to handle the polymer solution obtained by dissolving the powder obtained by the purification step in the solvent as the final product.

[0766] Specific examples of the solvent used in this case include ketones such as cyclohexanone and methyl-2-n-pentyl ketone described in paragraphs

[0144] to

[0145] of Japanese Patent Application Laid-Open No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, Ethers such as diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, 3-methoxypropionic acid methyl ester, 3-ethoxypropionic acid ethyl ester, tert-butyl acetate, tert-butyl propionate, propylene glycol monotert-butyl ether acetate; lactones such as GBL; alcohols such as diacetone alcohol (DAA); high-boiling point alcohol solvents such as diethylene glycol, propylene glycol, glycerol, 1,4-butanediol, 1,3-butanediol, etc.; and mixed solvents thereof.

[0767] In the polymer solution, the concentration of the polymer is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0768] The reaction solution and polymer solution are preferably filtered. Filtering can remove foreign matter and gel that may cause defects, which is effective in stabilizing quality.

[0769] The materials of the filter used in the above-mentioned filter filtration can be listed as: fluorocarbon, cellulose, nylon, polyester, hydrocarbon and other materials. The filtering step of the resist composition is preferably a filter formed of a fluorocarbon system called Teflon (registered trademark), a hydrocarbon system such as polyethylene, polypropylene, or nylon. The pore size of the filter can be appropriately selected in accordance with the target cleanliness, preferably below 100nm, and preferably below 20nm. In addition, these filters can be used alone or in combination. The filtering method can be to pass the solution only once, but it is better to circulate the solution and perform multiple filtrations. The filtering step can be implemented in any order and number of times in the manufacturing step of the polymer, and the reaction solution, the polymer solution or both after the polymerization reaction are preferably filtered.

[0770] The base polymer (B) may be used alone or in combination of two or more polymers having different composition ratios, Mw and / or Mw / Mn. In addition, the base polymer (B) may include a hydrogenated ring-opening metathesis polymer in addition to the aforementioned polymers, and the polymer described in Japanese Unexamined Patent Publication No. 2003-66612 may be used.

[0771] [(C) Organic solvent]

[0772] The chemically amplified resist composition of the present invention may also contain an organic solvent as the component (C). The organic solvent (C) is not particularly limited as long as it can dissolve the aforementioned components and the components described below. Such organic solvents include: ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ketone alcohols such as DAA; ethers such as PGME, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as GBL; mixed solvents thereof, etc.

[0773] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixed solvents thereof are preferred, since they have particularly excellent solubility in the base polymer of the component (B).

[0774] In the chemically amplified resist composition of the present invention, the content of the organic solvent (C) is preferably 200 to 5000 parts by mass, more preferably 400 to 3500 parts by mass, relative to 80 parts by mass of the base polymer (B). The organic solvent (C) may be used alone or in combination of two or more.

[0775] [(D) Photoacid generator]

[0776] In the chemically amplified resist composition of the present invention, when the onium salt of the component (A) functions as a quencher, a photoacid generator may be contained as the component (D). The photoacid generator is not particularly limited as long as it is a compound that generates an acid stronger than the sulfonic acid generated by the onium salt of the component (A) when irradiated with high-energy rays.

[0777] Preferable photoacid generators include those represented by the following formula (2) or (3).

[0778] [Chemistry 265]

[0779]

[0780] In formula (2), R 101 ~R 105 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 101 , R 102 and R 103 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. The hydrocarbon group may be exemplified as R in the description of formula (cation-1) and (cation-2). ct1 ~R ct5 The same examples are given for the hydrocarbon groups represented.

[0781] Specific examples of the cation and anion of the sulfonium salt represented by formula (2) include the same examples as those exemplified as the sulfonium cation represented by formula (cation-1). Specific examples of the cation and anion of the iodonium salt represented by formula (3) include the same examples as those exemplified as the iodonium cation represented by formula (cation-2).

[0782] In formula (2) and (3), Xa - It is an anion of a strong acid. Examples of the anion of a strong acid include those represented by any one of formulae (c1-1) to (c1-5).

[0783] Furthermore, the photoacid generator of the component (D) is preferably represented by the following formula (4).

[0784] [Chemistry 266]

[0785]

[0786] In formula (4), R 201 and R 202 Each of R is independently a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. 203 is a alkylene group having 1 to 30 carbon atoms which may contain a hetero atom. 201 , R 202 and R 203 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

[0787] R 201 and R 202The hydrocarbon group having 1 to 30 carbon atoms represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include: alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, such as decyl and adamantyl; aryl groups having 6 to 30 carbon atoms, such as phenyl, tolyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methyl naphthyl, ethyl naphthyl, n-propyl naphthyl, isopropyl naphthyl, n-butyl naphthyl, isobutyl naphthyl, sec-butyl naphthyl, tert-butyl naphthyl, anthracenyl; groups obtained by combining them, etc. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of -CH2- of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may be contained.

[0788] R 203The alkylene group having 1 to 30 carbon atoms represented by the present invention may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, and the like. Alkanediyl groups having 1 to 30 carbon atoms such as cyclopentanediyl, cyclohexanediyl, norbornanediyl and adamantanediyl; cyclic saturated alkylene groups having 3 to 30 carbon atoms such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene and tert-butylnaphthylene; and the like. Furthermore, part or all of the hydrogen atoms of the aforementioned alkylene group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned alkylene group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. may be contained. The aforementioned hetero atom is preferably an oxygen atom.

[0789] In formula (4), L D is a single bond, an ether bond, or an alkylene group having 1 to 20 carbon atoms which may contain a hetero atom. The alkylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include and are shown as R 203 The same examples are given for the alkylene groups represented by .

[0790] In formula (4), X a , X b , X c and X d are independently a hydrogen atom, a fluorine atom or a trifluoromethyl group. a , X b , X c and X d At least one of them is a fluorine atom or a trifluoromethyl group.

[0791] The photoacid generator represented by the formula (4) is preferably represented by the following formula (4').

[0792] [Chemistry 267]

[0793]

[0794] In formula (4'), L D Same as above. X e R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 Each is independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The same examples apply to the hydrocarbon groups represented by: p and q are each independently an integer of 0-5, and r is an integer of 0-4.

[0795] Examples of the photo-acid generator represented by formula (4) include the same examples as those exemplified as the photo-acid generator represented by formula (2) in JP-A-2017-26980.

[0796] Among the above-mentioned photoacid generators, those containing anions represented by formula (c1-1-1) or (c1-4) are particularly preferred because they have low acid diffusion and excellent solubility in solvents. Also, those represented by formula (4') are particularly preferred because they have extremely low acid diffusion.

[0797] When the chemically amplified resist composition of the present invention contains a photoacid generator (D), the content thereof is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 20 parts by mass, relative to 80 parts by mass of the base polymer (B). If the amount of the photoacid generator of the component (D) added is within the above range, the resolution is good, and there is no concern that foreign matter will be generated after the resist film is developed or peeled off, so it is more desirable. The photoacid generator (D) may be used alone or in combination of two or more.

[0798] [(E) Quencher]

[0799] In the chemically amplified resist composition of the present invention, when the onium salt as the component (A) functions as a photoacid generator, a quencher may be contained as the component (E).

[0800] Examples of the quencher of the component (E) include onium salts represented by the following formula (5).

[0801] [Chemistry 268]

[0802]

[0803] In formula (5), R 401 It is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom.

[0804] R 401 The hydrocarbon group having 1 to 40 carbon atoms represented by the present invention specifically includes alkyl groups having 1 to 40 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbon groups having 3 to 40 carbon atoms, such as decyl and adamantyl; aryl groups having 6 to 40 carbon atoms, such as phenyl, naphthyl, anthracenyl, etc. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and part of the -CH2- of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., and as a result, hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may be contained. In addition, R 401 Other examples include fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl.

[0805] Specific examples of the anion of the onium salt represented by the formula (5) include the following, but are not limited thereto.

[0806] [Chemistry 269]

[0807]

[0808] [Chemistry 270]

[0809]

[0810] [Chemistry 271]

[0811]

[0812] In formula (5), Mq + The onium cation is preferably a sulfonium cation represented by the above formula (cation-1), an iodonium cation represented by the above formula (cation-2), or an ammonium cation represented by the following formula (cation-3).

[0813] [Chemistry 272]

[0814]

[0815] In formula (cation-3), R ct6 ~Rct9 are each independently a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. ct6 With R ct7 They may also be bonded to each other and form a ring together with the nitrogen atom to which they are bonded. The hydrocarbon group may be exemplified as R in the description of formula (cation-1) and (cation-2). ct1 ~R ct5 The same examples are given for the hydrocarbon groups represented.

[0816] Examples of the ammonium cation represented by the formula (cation-3) include the following, but are not limited thereto.

[0817] [Chemistry 273]

[0818]

[0819] Specific examples of the onium salt represented by formula (5) include any combination of the above-mentioned anions and cations. In addition, these onium salts are easily prepared by ion exchange reactions using known organic chemical methods. For ion exchange reactions, reference can be made to, for example, Japanese Patent Publication No. 2007-145797.

[0820] The onium salt represented by formula (5) acts as a quencher in the chemically amplified resist composition of the present invention. This is because each of the counter anions of the onium salt is a conjugate base of a weak acid. Here, the so-called weak acid means an acid that exhibits an acidity that cannot deprotect the acid-labile group of the unit containing the acid-labile group used in the base polymer. When the onium salt represented by formula (5) is used in combination with an onium salt-type photoacid generator having a conjugate base of a strong acid such as sulfonic acid as a counter anion, it functions as a quencher. That is, when an onium salt that generates a strong acid such as sulfonic acid and an onium salt that generates a weak acid such as carboxylic acid are mixed and used, if the strong acid generated from the photoacid generator due to high-energy radiation irradiation collides with the unreacted onium salt having a weak acid anion, the weak acid is released by salt exchange and an onium salt having a strong acid anion is generated. In this process, the strong acid is exchanged for a weak acid with low catalytic ability, so the acid is apparently deactivated and the acid diffusion can be controlled.

[0821] In addition, the quencher of component (E) may be an onium salt having a sulfonium cation and a phenoxide anion site in the same molecule as described in Japanese Patent No. 6848776. In addition, an onium salt having a sulfonium cation and a carboxylate anion site in the same molecule as described in Japanese Patent No. 6583136 and Japanese Patent Application Laid-Open No. 2020-200311, and an onium salt having an iodonium cation and a carboxylate anion site in the same molecule as described in Japanese Patent No. 6274755 may also be used.

[0822] Here, it is considered that when the photoacid generator that generates a strong acid is an onium salt, the strong acid generated by high-energy ray irradiation can be exchanged for a weak acid as described above, while the weak acid generated by high-energy ray irradiation is not easy to collide with the unreacted onium salt that generates a strong acid to perform salt exchange. This is because the onium cation easily forms an ion pair with the anion of a stronger acid.

[0823] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (5) as a quencher of component (E), its content is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, relative to 80 parts by mass of the base polymer (B). If the onium salt quencher of component (E) is within the above range, the resolution is good and the sensitivity is not significantly reduced, which is more ideal. The onium salt represented by formula (5) can be used alone or in combination of two or more.

[0824] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as a quencher of the component (E). Examples of the nitrogen-containing compound include primary, secondary or tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Laid-Open No. 2008-111103, and in particular, amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group or a sulfonate bond. In addition, examples include compounds in which primary or secondary amines are protected with carbamate groups, such as the compounds described in Japanese Patent No. 3790649.

[0825] In addition, a sulfonium sulfonate salt having a nitrogen-containing substituent may be used as a nitrogen-containing compound. Such a compound will function as a quencher in the unexposed part, and will lose its quencher ability in the exposed part due to neutralization with the acid produced by itself, and function as a so-called photodisintegration base. By using a photodisintegration base, the contrast between the exposed part and the unexposed part can be made stronger. For example, the photodisintegration base can be referred to: Japanese Patent Publication No. 2009-109595, Japanese Patent Publication No. 2012-46501, etc.

[0826] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as the quencher of the component (E), the content thereof is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass, relative to 80 parts by mass of the base polymer (B). The nitrogen-containing compound may be used alone or in combination of two or more.

[0827] [(F) Surfactant]

[0828] The chemically amplified resist composition of the present invention may further contain a surfactant as the component (F). The surfactant (F) is preferably a surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer, or a surfactant that is insoluble or poorly soluble in water and an alkaline developer. Such surfactants can be described in Japanese Patent Application Publication No. 2010-215608 and Japanese Patent Application Publication No. 2011-16746.

[0829] The surfactant that is insoluble or poorly soluble in water and an alkaline developer is preferably, among the surfactants described in the aforementioned gazette, FC-4430 (manufactured by 3M Co.), SURFLON (registered trademark) S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), OLFINE (registered trademark) E1004 (manufactured by Nissin Chemical Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and an oxetane ring-opening polymer represented by the following formula (surf-1).

[0830] [Chemistry 274]

[0831]

[0832] Here, R, Rf, A, B, C, m, and n are irrelevant to the above description and apply only to formula (surf-1). R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. The aforementioned aliphatic group, as for the divalent group, can be listed as: ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentylene, etc.; as for the trivalent or tetravalent group, the following can be listed.

[0833] [Chemistry 275]

[0834]

[0835] In the formula, the dotted lines are atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.

[0836] Among them, 1,4-butylene group, 2,2-dimethyl-1,3-propylene group, and the like are preferred.

[0837] Rf is trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. m is an integer of 0 to 3, n is an integer of 1 to 4, the sum of n and m is the valence of R, and 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. In addition, the arrangement of the constituent units in formula (surf-1) is not specified, and they may be bonded in blocks or randomly. For details on the manufacture of surfactants based on partially fluorinated oxetane ring-opening polymers, see the specification of U.S. Patent No. 5,650,483, etc.

[0838] A surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer has the function of reducing water infiltration and leaching by aligning the surface of the resist film when a resist protective film is not used in ArF immersion lithography. Therefore, it is useful to suppress the dissolution of water-soluble components from the resist film and reduce damage to the exposure device. In addition, it is useful because it can be dissolved and is not likely to become a foreign matter that causes defects during development with an alkaline aqueous solution after exposure or after post-exposure baking (PEB). Such a surfactant is insoluble or poorly soluble in water and soluble in an alkaline developer. It is a polymer-type surfactant, also called a hydrophobic resin, and is particularly preferably highly water-repellent and improves water sliding properties.

[0839] Specific examples of such polymeric surfactants include those containing at least one repeating unit selected from the group consisting of repeating units represented by any one of the following formulae (6A) to (6E).

[0840] [Chemistry 276]

[0841]

[0842] In formulas (6A) to (6E), R B W is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 It is -CH2-, -CH2CH2-, -O- or two -H separated from each other. s1 R are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. s2 is a single bond, or a linear or branched alkylene group having 1 to 5 carbon atoms. s3 R are each independently a hydrogen atom, a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group. s3 When it is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between the carbon-carbon bonds. s4 is a (u+1)-valent hydrocarbon group or a fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer of 1 to 3. s5 are independently a hydrogen atom, or -C(=O)-OR sa Represents a group. sa is a fluorinated hydrocarbon group having 1 to 20 carbon atoms. s6 It is a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, and an ether bond or a carbonyl group may be inserted between the carbon-carbon bonds.

[0843] R s1The hydrocarbon group having 1 to 10 carbon atoms represented by is a saturated hydrocarbon group, and may be any of a straight chain, a branched, or a cyclic group. Specific examples thereof include: alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; cyclic saturated hydrocarbon groups having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl. Among them, those having 1 to 6 carbon atoms are preferred.

[0844] R s2 The alkylene group represented by is preferably a saturated alkylene group, and may be straight-chain, branched, or cyclic. Specific examples thereof include methylene, ethylene, propylene, butylene, and pentylene.

[0845] R s3 or R s6 The hydrocarbon group represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include: saturated hydrocarbon groups; aliphatic unsaturated hydrocarbon groups such as alkenyl and alkynyl, etc., preferably saturated hydrocarbon groups. In addition to the saturated hydrocarbon groups listed as examples of R s1 In addition to the hydrocarbon groups represented by , undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, etc. can be mentioned. s3 or R s6 The fluorinated hydrocarbon groups represented by may be groups in which a part or all of the hydrogen atoms bonded to the carbon atoms of the above hydrocarbon groups are substituted with fluorine atoms. As mentioned above, an ether bond or a carbonyl group may be inserted between the carbon-carbon bonds.

[0846] R s3 Specific examples of the acid-labile group represented by include groups represented by the above formulae (AL-3) to (AL-5), trialkylsilyl groups each of which is an alkyl group having 1 to 6 carbon atoms, and alkyl groups containing an oxo group having 4 to 20 carbon atoms.

[0847] R s4 The (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group represented by may be linear, branched or cyclic, and specific examples thereof include groups obtained by further removing u hydrogen atoms from the above-mentioned hydrocarbon group or fluorinated hydrocarbon group.

[0848] R saThe fluorinated hydrocarbon group represented is preferably saturated, and may be linear, branched, or cyclic. Specific examples thereof include those in which a part or all of the hydrogen atoms of the aforementioned hydrocarbon group are substituted by fluorine atoms, and specific examples thereof include trifluoromethyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoro-1-propyl, 3,3,3-trifluoro-2-propyl, 2,2,3,3-tetrafluoropropyl, 1,1,1,3,3,3-hexafluoroisopropyl, 2,2,3,3,4,4,4-heptafluorobutyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, 2-(perfluorodecyl)ethyl, and the like.

[0849] Specific examples of the repeating unit represented by any one of formulae (6A) to (6E) include, but are not limited to, the following. B Same as above.

[0850] [Chemistry 277]

[0851]

[0852] [Chemistry 278]

[0853]

[0854] [Chemistry 279]

[0855]

[0856] [Chemistry 280]

[0857]

[0858] [Chemistry 281]

[0859]

[0860] [Chemistry 282]

[0861]

[0862] The aforementioned polymeric surfactant may further contain other repeating units other than the repeating units represented by formulae (6A) to (6E). Other repeating units may include repeating units derived from methacrylic acid, α-trifluoromethylacrylic acid derivatives, etc. In the polymeric surfactant, the content of the repeating units represented by formulae (6A) to (6E) is preferably 20 mol% or more, more preferably 60 mol% or more, and even more preferably 100 mol% in all the repeating units.

[0863] The Mw of the aforementioned polymer surfactant is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. The Mw / Mn is preferably 1.0 to 2.0, more preferably 1.0 to 1.6.

[0864] The method for synthesizing the aforementioned polymer surfactant may include: providing a monomer containing an unsaturated bond that provides a repeating unit represented by formula (6A) to (6E) and other repeating units as needed, adding a free radical initiator and heating to polymerize it in an organic solvent. The organic solvent used in the polymerization may include toluene, benzene, THF, diethyl ether, dioxane, etc. The polymerization initiator may include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylpropionic acid) dimethyl ester, benzoyl peroxide, lauroyl peroxide, etc. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. The acid-labile group may be directly introduced into the monomer, or it may be protected or partially protected after polymerization.

[0865] When synthesizing the aforementioned polymer surfactant, a known chain transfer agent such as dodecyl mercaptan or 2-mercaptoethanol may be used to adjust the molecular weight. In this case, the amount of the chain transfer agent added is preferably 0.01 to 10 mol % relative to the total molar number of the monomers to be polymerized.

[0866] When the chemically amplified resist composition of the present invention contains a surfactant (F), the content thereof is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the base polymer (B). If the content of the surfactant (F) is 0.1 parts by mass or more, the receding contact angle between the resist film surface and water will be sufficiently improved, and if it is 50 parts by mass or less, the dissolution rate of the resist film surface to the developer is low, and the height of the formed fine pattern is sufficiently maintained. The surfactant (F) may be used alone or in combination of two or more.

[0867] [(G) Other ingredients]

[0868] The chemically amplified resist composition of the present invention may contain, as (G) other components, a compound that decomposes by acid and generates acid (acid multiplication compound), an organic acid derivative, a fluorine-substituted alcohol, a compound with a Mw of 3,000 or less that changes solubility in a developer by the action of an acid (dissolution inhibitor), etc. The acid multiplication compound may refer to the compounds described in Japanese Patent Application Laid-Open No. 2009-269953 or Japanese Patent Application Laid-Open No. 2010-215608. When the acid multiplication compound is contained, the content thereof is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass, relative to 80 parts by mass of the base polymer (B). If the content is too high, it may be difficult to control the diffusion of the acid, and the resolution may be deteriorated, and the pattern shape may be deteriorated. The organic acid derivative, the fluorine-substituted alcohol, and the dissolution inhibitor may refer to the compounds described in Japanese Patent Application Laid-Open No. 2009-269953 or Japanese Patent Application Laid-Open No. 2010-215608.

[0869] [Pattern Formation Method]

[0870] The pattern forming method of the present invention comprises the following steps:

[0871] Using the chemically amplified resist composition to form a resist film on a substrate,

[0872] exposing the resist film to high energy radiation, and

[0873] The exposed resist film is developed using a developer.

[0874] The aforementioned substrate can be used, 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.).

[0875] The resist film can be formed by, for example, applying the chemically amplified resist composition onto a substrate by spin coating or the like in a manner such that the film thickness is preferably 0.05 to 2 μm, and pre-baking it on a hot plate at preferably 60 to 150° C. for 1 to 10 minutes, more preferably 80 to 140° C. for 1 to 5 minutes.

[0876] Examples of high-energy radiation used for exposure of the resist film include KrF excimer laser, ArF excimer laser, EB, EUV, etc. When KrF excimer laser, ArF excimer laser, or EUV is used for exposure, a mask for forming a target pattern can be used, and the exposure dose is preferably 1 to 200 mJ / cm 2 , becomes 10~100mJ / cm 2When EB is used, a mask for forming a target pattern or directly exposure is preferably 1 to 300 μC / cm 2 , becomes 10~200μC / cm 2 A better way to irradiate.

[0877] In addition to the usual exposure method, the exposure may be performed by an immersion method in which a liquid having a refractive index of 1.0 or more is inserted between the resist film and the projection lens. In this case, a water-insoluble protective film may be used.

[0878] The aforementioned water-insoluble protective film is used to prevent elution from the resist film and to improve the water sliding property of the film surface, and is roughly divided into two types. One is an organic solvent stripping type that must be stripped using an organic solvent that does not dissolve the resist film before alkaline aqueous solution development, and the other is an alkaline aqueous solution soluble type that is soluble in an alkaline developer and removes the protective film while removing the soluble part of the resist film. The latter is particularly preferably a material made of 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 as a base, and dissolved in an alcohol solvent with a carbon number of 4 or more, an ether solvent with a carbon number of 8 to 12, and a mixed solvent thereof. It can also be made into a material made by dissolving the aforementioned water-insoluble and alkaline developer soluble surfactant in an alcohol solvent with a carbon number of 4 or more, an ether solvent with a carbon number of 8 to 12, or a mixed solvent thereof.

[0879] After the exposure, PEB may be performed. 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.

[0880] For development, for example, a developer containing an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) preferably at a concentration of 0.1 to 5% by mass, more preferably 2 to 3% by mass, is used, and development is performed using common methods such as dipping, puddle, and spraying for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, thereby dissolving the exposed portion and forming a desired pattern on the substrate.

[0881] After the resist film is formed, pure water rinsing may be performed to extract the acid generator and the like from the film surface or to wash away particles. Rinsing may also be performed to remove water remaining on the film after exposure.

[0882] In addition, a double patterning method can also be used for pattern formation. The double patterning method includes: a groove method in which a 1:3 groove pattern is processed by a first exposure and etching, and then the position is shifted and a 1:3 groove pattern is formed by a second exposure to form a 1:1 pattern, and a line method in which a 1:3 isolated residual pattern is processed by a first exposure and etching, and then the position is shifted and a 1:3 isolated residual pattern is formed under the first substrate by a second exposure, and the second substrate is processed to form a 1:1 pattern with half the pitch.

[0883] In the pattern forming method of the present invention, a negative tone development method in which an organic solvent is used as a developer instead of the alkaline aqueous solution to dissolve the unexposed portion may be used.

[0884] In the above-mentioned organic solvent development, the developer that can be used is: 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, amyl acetate, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, Ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0885] Example

[0886] Hereinafter, the present invention will be specifically described with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples.

[0887] IR: NICOLET 6700 manufactured by Thermo Fisher Scientific

[0888] · 1 H-NMR: ECA-500 manufactured by JEOL Ltd.

[0889] ·MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0890] [1] Synthesis of onium salts

[0891] [Example 1-1] Synthesis of onium salt Salt-1

[0892] [Chemistry 283]

[0893]

[0894] (1) Synthesis of intermediate In-1

[0895] Under nitrogen environment, a Grignard reagent was prepared from magnesium (1.5 g), raw material SM-1 (18.1 g) and THF (50 mL). Thereafter, dry ice (30 g) was suspended in THF (100 mL), and the prepared Grignard reagent was added thereto. After addition, the mixture was stirred until the dry ice sublimated. After confirming that the dry ice sublimated, 20% by mass hydrochloric acid (11.0 g) was added to stop the reaction. The target was extracted twice with ethyl acetate (100 mL), and the usual aqueous work-up was performed. After the solvent was distilled off, it was recrystallized with hexane to obtain 13.1 g of the intermediate In-1 (yield 82%) as white crystals.

[0896] (2) Synthesis of intermediate In-2

[0897] Under nitrogen environment, add intermediate In-1 (5.9 g), raw material SM-2 (4.5 g), DMAP (0.3 g) and dichloromethane (30 g) to the reaction vessel and cool with an ice bath. While maintaining the temperature in the reaction vessel below 20°C, add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (4.2 g) in powder form. After addition, warm to room temperature and mature for 12 hours. After maturation, add water to stop the reaction, and perform the usual aqueous work-up. After distilling off the solvent, add diisopropyl ether for washing, thereby obtaining 9.0 g of intermediate In-2 (yield 95%) in the form of an oil.

[0898] (3) Synthesis of onium salt Salt-1

[0899] In a nitrogen atmosphere, the intermediate In-2 (9.0 g), the raw material SM-3 (7.5 g), dichloromethane (40 g) and water (30 g) were added to the reaction vessel, and after stirring for 30 minutes, the organic layer was separated and extracted, washed with water, and then concentrated under reduced pressure. Diisopropyl ether was added to the concentrate for recrystallization, thereby obtaining 11.3 g of the target onium salt Salt-1 (yield 90%) as a white crystal.

[0900] The IR spectrum data and TOF-MS results of Salt-1 are shown below. 1 The results of H-NMR / DMSO-d6) are as follows Figure 1 shown.

[0901] IR(D-ATR): ν=3455,3086,3060,2966,2875,1716,1651,1605,1506,1474,1449,1421,1384,1 352,1291,1219,1201,1112,1036,988,894,833,764,735,707,681,643,613,525,490,424cm -1 .

[0902] MALDI TOF-MS: POSITIVE M + 261 (equivalent to C 18 H 13 S + )

[0903] NEGATIVE M - 373 (equivalent to C 17 H 22 FO6S - )

[0904] [Examples 1-2 to 1-10] Synthesis of Onium Salts Salt-2 to Salt-10

[0905] Onium salts Salt-2 to Salt-10 represented by the following formulae were synthesized using corresponding raw materials and known organic chemical reactions.

[0906] [Chemistry 284]

[0907]

[0908] [Chemistry 285]

[0909]

[0910] [2] Synthesis of base polymer

[0911] [Synthesis Example] Synthesis of base polymers (polymers P-1 to P-5)

[0912] The monomers were combined and copolymerized in MEK as a solvent, and then added to hexane. The precipitated solid was washed with hexane, separated and dried to obtain base polymers (polymers P-1 to P-5) with the following compositions. 1 The structure was confirmed by H-NMR, and the Mw and Mw / Mn were confirmed by GPC (solvent: DMF, standard: polystyrene).

[0913] [Chemistry 286]

[0914]

[0915] [Chemistry 287]

[0916]

[0917] [3] Preparation of chemically amplified resist composition

[0918] [Examples 2-1 to 2-36, Comparative Examples 1-1 to 1-20]

[0919] The onium salts of the present invention (Salt-1 to Salt-10), comparative onium salts (Salt-A to Salt-D), photoacid generators (PAG-X, PAG-Y), base polymers (P-1 to P-5) and quenchers (Q-1 to Q-4) were dissolved in a solvent containing 0.01 mass % of surfactant A (OMNOVA) according to the compositions shown in Tables 1 and 2 below to prepare solutions, and the solutions were filtered with a 0.2 μm Teflon (registered trademark) filter to prepare chemically amplified resist compositions (R-1 to R-36 and CR-1 to CR-20).

[0920] [Table 1]

[0921]

[0922]

[0923] [Table 2]

[0924]

[0925] In Tables 1 and 2, the solvent, the photoacid generators PAG-X and PAG-Y, the comparative onium salts Salt-A to Salt-D, the quenchers Q-1 to Q-4, and the surfactant A are as follows.

[0926] Solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0927] DAA (Diacetone Alcohol)

[0928] Photoacid generator: PAG-X, PAG-Y

[0929] [Chemistry 288]

[0930]

[0931] ·Comparative onium salts: Salt-A to Salt-D

[0932] [Chemistry 289]

[0933]

[0934] Quencher: Q-1~Q-4

[0935] [Chemistry 290]

[0936]

[0937] Surfactant A: 3-methyl-3-(2,2,2-trifluoroethoxymethyl)oxetane, tetrahydrofuran, 2,2-dimethyl-1,3-propanediol copolymer (manufactured by OMNOVA)

[0938] [Chemistry 291]

[0939]

[0940] a:(b+b'):(c+c')=1:4~7:0.01~1 (molar ratio)

[0941] Mw=1500

[0942] [4]EUV lithography evaluation (1)

[0943] [Examples 3-1 to 3-36, Comparative Examples 2-1 to 2-20]

[0944] Each chemically amplified resist composition (R-1 to R-36, CR-1 to CR-20) was spin-coated on a Si substrate on which a silicon-containing spin-coating hard mask SHB-A940 (containing 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and pre-baked at 100° C. for 60 seconds using a hot plate to obtain a resist film with a film thickness of 50 nm. The resist film was exposed to light using an EUV scanning exposure machine NXE3400 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, dipole illumination) while changing the exposure dose and focus (exposure dose step: 1 mJ / cm 2 , focal distance: 0.020 μm) while performing exposure of an LS pattern with a size of 18 nm and a pitch of 36 nm on the wafer, and after exposure, PEB was performed for 60 seconds at the temperature shown in Tables 3 and 4. Thereafter, immersion development was performed for 30 seconds with a 2.38 mass % TMAH aqueous solution, and elution was performed with an elution material containing a surfactant, and spin drying was performed to obtain a positive pattern.

[0945] The obtained LS pattern was observed using Hitachi High-Tech Co., Ltd.'s length measurement SEM (CG6300), and the sensitivity, EL, LWR, depth of focus (DOF), and collapse limit were evaluated according to the following methods. The results are shown in Tables 3 and 4.

[0946] [Sensitivity evaluation]

[0947] The optimum exposure dose Eop (mJ / cm2) for obtaining a LS pattern with a line width of 18 nm and a pitch of 36 nm was calculated. 2 ) and let it be the sensitivity. The smaller the value, the higher the sensitivity.

[0948] [EL evaluation]

[0949] From the exposure amount formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm pitch width in the above LS pattern, EL (unit: %) was calculated by the following formula. The larger the value, the better the performance.

[0950] EL(%)=(|E1-E2| / E op )×100

[0951] E1: Provides the optimal exposure for LS pattern with line width of 16.2nm and pitch of 36nm

[0952] E2: Provides the optimal exposure for LS pattern with line width of 19.8nm and pitch of 36nm

[0953] E op :Provide the optimal exposure for LS pattern with line width of 18nm and pitch of 36nm

[0954] [LWR evaluation]

[0955] The dimensions of LS patterns obtained by irradiation with Eop were measured at 10 locations in the length direction of the line, and the value (3σ) tripled by the standard deviation (σ) was calculated as LWR. The smaller this value is, the smaller the roughness and the more uniform the line width pattern can be obtained.

[0956] [DOF evaluation]

[0957] The focal depth is evaluated by finding the focal range formed within the range of ±10% (16.2 to 19.8 nm) of the size of 18 nm in the LS pattern. The larger the value, the wider the focal depth.

[0958] [Evaluation of Collapse Limit of Line Pattern]

[0959] The line size of each exposure amount at the optimal focus of the LS pattern was measured at 10 points along the length direction. The thinnest line size that can be obtained without collapse is taken as the collapse limit size. The smaller this value is, the better the collapse limit is.

[0960] [Table 3]

[0961]

[0962]

[0963] [Table 4]

[0964]

[0965] From the results shown in Tables 3 and 4, it can be seen that the chemically amplified resist composition containing the photoacid generator of the present invention has good sensitivity, and is excellent in EL, LWR and DOF. In addition, it can be confirmed that the value of the collapse limit is small, and the pattern collapse resistance is strong even in fine pattern formation. Therefore, it is shown that the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[0966] [5]EUV lithography evaluation (2)

[0967] [Examples 4-1 to 4-36, Comparative Examples 3-1 to 3-20]

[0968] Each chemically amplified resist composition (R-1 to R-36, CR-1 to CR-20) was spin-coated on a Si substrate on which a silicon-containing spin-coating hard mask SHB-A940 (containing 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and pre-baked at 105° C. for 60 seconds using a hot plate to obtain a resist film with a film thickness of 50 nm. The resist film was exposed using an EUV scanning exposure machine NXE3400 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask with a hole pattern having a size of 46 nm pitch and +20% deviation on the wafer), and then PEB was performed for 60 seconds using a hot plate at the temperature described in Tables 5 and 6, and development was performed for 30 seconds using a 2.38% by mass TMAH aqueous solution to form a hole pattern having a size of 23 nm.

[0969] The exposure amount when the hole size was formed at 23 nm was measured using a Hitachi High-Tech (stock) length measurement SEM (CG6300), and this was taken as the sensitivity. The size of 50 holes at this time was measured, and the value (3σ) three times the standard deviation (σ) obtained from the result was taken as the size variation (CDU). The results are shown in Tables 5 and 6.

[0970] [Table 5]

[0971]

[0972]

[0973] [Table 6]

[0974]

[0975]

[0976] The results shown in Tables 5 and 6 confirm that the chemically amplified resist composition of the present invention has good sensitivity and excellent CDU.

Claims

1. An onium salt represented by the following formula (1); Wherein, n1 is 0 or 1; n2 is 1, 2 or 3; n3 is 1, 2, 3 or 4; n4 is an integer from 0 to 4; however, when n1 is 0, 2≤n2+n3+n4≤5, and when n1 is 1, 2≤n2+n3+n4≤7; R AL It is an acid-labile group; R F is a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms; when n3 ≥ 2, each R F They can be the same or different from each other; R F AND-OR AL Bonded to adjacent carbon atoms; L A and L B are independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond; X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain heteroatoms; R 1 is a hydrocarbon group having 1 to 20 carbon atoms which may also contain heteroatoms; R 2 It is a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom other than a fluorine atom; Z + It is an onium cation.

2. The onium salt according to claim 1, wherein The acid-labile group is represented by the following formula (AL-1) or (AL-2); In the formula, R L1 , R L2 and R L3 are each independently a hydrocarbon group having 1 to 12 carbon atoms, wherein a portion of -CH2- in the hydrocarbon group may be substituted by -O- or -S-, and when the hydrocarbon group contains an aromatic ring, a portion or all of the hydrogen atoms in the aromatic ring may be substituted by a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 4 carbon atoms which may also contain a halogen atom, or an alkoxy group having 1 to 4 carbon atoms which may also contain a halogen atom; and R L1 and R L2 They may also be bonded to each other to form a ring, and a portion of the -CH2- of the ring may be substituted by -O- or -S-; R L4 and R L5 are independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; L6 is a hydrocarbon group having 1 to 20 carbon atoms, wherein a portion of -CH2- in the hydrocarbon group may be substituted by -O- or -S-; and R L5 and R L6 They can also bond to each other and to the carbon atoms to which they are bonded and to L C Together they form a heterocyclic group having 3 to 20 carbon atoms, and a portion of the -CH2- in the heterocyclic group may be substituted by -O- or -S-; L C is -O- or -S-; m1 is 0 or 1; m2 is 0 or 1; * indicates a bond to an adjacent -O- atom.

3. The onium salt according to claim 1, wherein R 2 is a group represented by the following formula (R2-1) or (R2-2); In the formula, n5 is an integer of 1 to 4; n6 is 0 or 1; n7 is an integer of 0 to 4 when n6 is 0, and is an integer of 0 to 6 when n6 is 1; R 3 and R 4 are each independently a hydrogen atom, a halogen atom other than a fluorine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom other than a fluorine atom; and R 3 and R 4 They can also bond to each other and to the carbon atoms to which they are bonded to form rings; R 5 is a halogen atom other than a fluorine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom other than a fluorine atom; and, when n7 ≥ 2, multiple R 5 They can also bond to each other and to the carbon atoms to which they are bonded to form rings; * indicates respectively and L B and -SO3 - of atomic bonds.

4. The onium salt according to claim 1, represented by the following formula (1A); In the formula, n1~n4, R AL , R F , L A , X L , R 1 , R 2 and Z + Same as above.

5. The onium salt according to claim 1, wherein Z + It is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2); In the formula, R ct1 ~R ct5 are independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom; and R ct1 and R ct2 They may also bond to each other and to the sulfur atom to which they are bonded to form a ring. 6 . A chemically amplified resist composition comprising the onium salt according to claim 1 .

7. The chemically amplified resist composition according to claim 6, comprising a base polymer having a repeating unit represented by the following formula (a1); In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X 1 is a single bond, phenylene, naphthylene or *-C(=O)-OX 11 -, and the phenylene group or naphthylene group may be substituted by an alkoxy group having 1 to 10 carbon atoms which may also contain a fluorine atom or a halogen atom; X 11 It is a saturated alkylene group, phenylene group or naphthylene group having 1 to 10 carbon atoms, and the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring; * represents an atomic bond with a carbon atom of the main chain; AL 1 It is an acid-labile group.

8. The chemically amplified resist composition according to claim 7, wherein: The base polymer contains a repeating unit represented by the following formula (a2); In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X 2 is a single bond or *-C(=O)-O-; * represents an atomic bond with a carbon atom of the main chain; R 11 is a halogen atom, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl oxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom; AL 2 It is an acid-labile group; a is an integer from 0 to 4.

9. The chemically amplified resist composition according to claim 7, wherein: The base polymer contains a repeating unit represented by the following formula (b1) or (b2); In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; Y 1 is a single bond or *-C(=O)-O-; * represents an atomic bond with a carbon atom of the main chain; R 21 A group having 1 to 20 carbon atoms and containing at least one structure selected from the group consisting of a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-); R 22 is a halogen atom, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl oxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom; b is an integer from 1 to 4; c is an integer from 0 to 4; however, 1≤b+c≤5.

10. The chemically amplified resist composition according to claim 7, wherein: The base polymer contains at least one selected from the group consisting of a repeating unit represented by the following formula (c1), a repeating unit represented by the following formula (c2), a repeating unit represented by the following formula (c3), and a repeating unit represented by the following formula (c4); In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; Z 1 is a single bond or a phenylene group; Z 2 **-C(=O)-OZ 21 -, **-C(=O)-NH-Z 21 -or**-OZ 21 -;Z 21 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group; Z 3 are independently a single bond, a phenylene group, a naphthylene group or *-C(=O)-OZ 31 -;Z 31 It is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring; Z 4 are independently single bonds, ***-Z 41 -C(=O)-O-、***-C(=O)-NH-Z 41 -or***-OZ 41 -;Z 41 It is a hydrocarbon group having 1 to 20 carbon atoms which may also contain heteroatoms; Z 5 are independently single bonds, ****-Z 51 -C(=O)-O-、****-C(=O)-NH-Z 51 -or****-OZ 51 -;Z 51 It is a hydrocarbon group having 1 to 20 carbon atoms which may also contain heteroatoms; Z 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 61 -, *-C(=O)-N(H)-Z 61 -or*-OZ 61 -;Z 61 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group; * indicates the atomic bond with the carbon atom of the main chain; ** indicates the bond with Z 1 Atomic bonds; *** indicates and Z 3 Atomic bonds; **** indicates Z 4 Atomic bonds; R 31 and R 32 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; and R 31 and R 32 They can also bond to each other and to the sulfur atoms to which they are bonded to form a ring; L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond; R 1 and Rf 2 are independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; R 3 and Rf 4 are independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; R 5 and Rf 6 are independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; however, all Rf 5 and Rf 6 It will not be a hydrogen atom at the same time; M - It is a non-nucleophilic counter ion; A + is an onium cation; d is an integer from 0 to 3.

11. The chemically amplified resist composition according to claim 6, further comprising an organic solvent.

12. The chemically amplified resist composition according to claim 6, wherein: The onium salt functions as a quencher.

13. The chemically amplified resist composition according to claim 12, further comprising an acid generator capable of generating sulfonic acid, methylated acid, or imidic acid.

14. The chemically amplified resist composition according to claim 6, wherein: The onium salt functions as a photoacid generator.

15. The chemically amplified resist composition according to claim 14, further comprising a quencher.

16. The chemically amplified resist composition according to claim 6, further comprising a surfactant.

17. A pattern forming method comprising the following steps: forming a resist film on a substrate using the chemically amplified resist composition according to claim 6, exposing the resist film to high energy radiation, and The exposed resist film is developed using a developer.

18. The pattern forming method according to claim 17, wherein: The high-energy ray is KrF excimer laser, ArF excimer laser, electron beam or extreme ultraviolet ray with a wavelength of 3 to 15 nm.

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