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: an onium salt used in a chemically amplified resist composition which has excellent solvent solubility, high sensitivity, high contrast, and excellent lithography performance such as exposure margin and line width roughness in optical lithography using high-energy rays; a chemically amplified resist composition comprising the onium salt as a photoacid generator; and a pattern forming method using the chemically amplified resist composition. [Solution] An onium salt represented by formula (1). In the # imgabs0 # formula, one of R13 and R14 is a group having a partial structure represented by formula (1a); in the formula # imgabs 1 #, Q1 to Q3 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, but when Q1 and Q2 are both hydrogen atoms, Q3 is a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. In addition, the total number of fluorine atoms in Q1-Q3 is 2 or more.

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 required to be miniaturized. As for the next generation of micro-processing technology, far ultraviolet lithography and extreme ultraviolet (EUV) lithography are considered to be promising. 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 device manufacturing of the 130nm node, and has become the main lithography technology since the 90nm node device. As for the subsequent lithography technology of the 45nm node, the 157nm lithography using F2 laser was originally considered promising, but it was pointed out that the development was delayed due to various problems. Therefore, by inserting a liquid 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 is designed to be 1.0 or more, and high-resolution ArF immersion lithography has come to the fore (Non-Patent Document 1) and is now in the practical stage. In this immersion lithography, a resist composition that is not easily dissolved in water is sought.

[0004] In ArF lithography, in order to prevent the degradation of precise and expensive optical materials, a highly sensitive resist composition that can fully demonstrate resolution with a small exposure is sought. As for the method of achieving this, it is most common to select a component that is highly transparent at a wavelength of 193nm. For example, regarding the base polymer, some people have proposed polyacrylic acid and its derivatives, norbornene-maleic anhydride alternating copolymers, polynorbornene, ring-opening metathesis polymers, ring-opening metathesis polymer hydrides, etc., and have achieved a certain degree of success in terms of improving the transparency of the resin monomer.

[0005] In recent years, along with positive tone resists developed with alkaline aqueous solutions, negative tone resists developed with organic solvents have also attracted attention. In order to distinguish very fine hole patterns that cannot be achieved with positive tone by negative tone exposure, a positive resist composition with high resolution is used, and a negative pattern is formed by developing with an organic solvent. Then, some people have conducted research on obtaining a double resolution by combining two developments, namely, alkaline aqueous solution development and organic solvent development. As for the ArF resist composition for negative tone development with organic solvents, a known positive ArF resist composition can be used, and the pattern forming method using it is 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 has also progressed day by day. Some people have also conducted various studies on photoacid generators, generally using sulfonium salts composed of triphenylsulfonium cations and perfluoroalkanesulfonic acid anions. However, the generated acid, that is, perfluoroalkanesulfonic acid, especially perfluorooctanesulfonic acid (PFOS), has doubts about its difficulty in decomposition, bioconcentration, and toxicity, which is severe for its application 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, making it difficult to achieve high resolution. In response to this problem, various developments have been made on partially fluorinated alkanesulfonic acids and their salts. For example, Patent Document 1 describes, as a prior art, a photoacid generator that generates α,α-difluoroalkanesulfonic acid by exposure, specifically, a photoacid generator that generates di(4-tert-butylphenyl)iodonium-1,1-difluoro-2-(1-naphthyl)ethanesulfonate and α,α,β,β-tetrafluoroalkanesulfonic acid. However, although these are all fluorine-substituted products with reduced fluorine substitution rates, they do not have decomposable substituents such as ester structures, so the environmental safety considerations due to easy decomposition are insufficient. In addition, there are limitations on the molecular design for changing the size of the alkanesulfonic acid, and there are problems such as high prices for starting materials containing fluorine atoms.

[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, which will lead to a decrease in mask fidelity and degradation of pattern rectangularity due to the increase in the size deviation on the wafer relative to the size deviation of the mask (mask error factor (MEF)). Therefore, in order to fully obtain the benefits of the shorter wavelength and higher NA of the light source, it is necessary to increase the dissolution contrast of the known material or inhibit the acid diffusion. As for one of the improvement strategies, if the baking temperature is lowered, the acid diffusion will become smaller. As a result, the MEF can be improved, but the sensitivity will inevitably decrease.

[0008] Introducing a high-bulky substituent or polar group into a 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 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 introduced with a high-bulky substituent has low acid diffusion. In addition, Patent documents 5 to 7 describe photoacid generators that introduce condensed ring lactones, sultones, and thiolactones as polar groups. Although the acid diffusion suppression effect caused by the introduction of polar groups has confirmed a certain degree of performance improvement, the current high degree of control of acid diffusion is still insufficient, and from a comprehensive perspective of MEF, pattern shape, sensitivity, etc., it has not yet been able to meet the photolithography performance.

[0009] The introduction of polar groups into the anion of the photoacid generator is effective in inhibiting acid diffusion, but it becomes a disadvantage from the perspective of solvent solubility. In Patent Documents 8 and 9, in order to improve solvent solubility, experiments were conducted to introduce alicyclic groups into the cationic part of the photoacid generator to ensure solvent solubility, specifically, cyclohexane rings and adamantane rings were introduced. By introducing such alicyclic groups, solubility is improved, but in order to ensure solubility, a certain degree of carbon number is required, resulting in a larger molecular structure volume of the photoacid generator, so that when forming fine patterns, the lithography performance such as line width roughness (LWR) and dimensional uniformity (CDU) is deteriorated.

[0010] In addition, Patent Document 10 describes a photoacid generator that generates fluoroalkanesulfonic acid in which the anion has an aromatic condensed ring derived from anthracene. Although this has confirmed a certain degree of improvement in lithography performance, when the number of fluorine atoms bonded to the alkanesulfonic acid structure is 2 to 4, the organic solvent solubility is not sufficiently high, and there is a concern that it will precipitate in the solvent. In order to respond to the demand for further miniaturization, the development of novel photoacid generators is important, and it is expected that the acid diffusion is fully controlled, the solvent solubility is excellent, and the development of photoacid generators that improve lithography performance will be developed.

[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. 7109178

[0023] Non-patent literature

[0024] [Non-patent document 1] Journal of Photopolymer Science and Technology, Vol. 17, No. 4, p. 587-601 (2004) Summary of the invention

[0025] [Problems to be solved by the invention]

[0026] In response to recent demands for high resolution of resist patterns, resist compositions using known onium salt-type photoacid generators cannot sufficiently suppress acid diffusion, resulting in degradation of lithography performance such as contrast, MEF, and LWR.

[0027] 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 having excellent solvent solubility, high sensitivity, high contrast, and excellent lithography performance such as exposure margin (EL) and LWR, especially in optical lithography using high-energy rays such as KrF excimer laser, ArF excimer laser, electron beam (EB), and EUV; a chemically amplified resist composition containing the onium salt as a photoacid generator; and a pattern forming method using the chemically amplified resist composition.

[0028] [Methods to solve the problem]

[0029] The inventors of the present application have repeatedly conducted intensive studies to achieve the aforementioned purpose, and as a result, have found that an onium salt having an alkanesulfonic acid structure with a substituted ring structure and a trifluoromethyl group and having 5 or more fluorine atoms has excellent solvent solubility, and that a chemically amplified resist composition using the salt as a photoacid generator has high sensitivity and high contrast, and has excellent EL, LWR and other lithography properties, and is extremely effective in forming fine patterns, thereby completing the present invention.

[0030] That is, the present invention provides the following onium salt, chemically amplified resist composition and pattern forming method.

[0031] 1. An onium salt represented by the following formula (1);

[0032] [Chemistry 1]

[0033]

[0034] In the formula, R 1 ~R 12 Each is independently a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom;

[0035] R 13 and R 14 One of them is a group having a partial structure represented by the following formula (1a), and the other is a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom;

[0036] Again, R 1 ~R 14 At least two of them may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, or may be bonded to the carbon atoms to which they are bonded and the carbon atoms between them to form a ring;

[0037] Z + is an onium cation;

[0038] [Chemistry 2]

[0039]

[0040] Where, L A and L B are each independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond;

[0041] X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom;

[0042] Q 1 ~Q 3 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; but when Q 1 and Q2 When all are hydrogen atoms, Q 3 is a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; and, Q 1 ~Q 3 The total number of fluorine atoms in is 2 or more.

[0043] 2. The onium salt of 1, which is represented by the following formula (1A);

[0044] [Chemistry 3]

[0045]

[0046] In the formula, R 1 ~R 13 , L A , X L , Q 1 ~Q 3 , and Z + Same as above.

[0047] 3. The onium salt of 2, which is represented by the following formula (1B);

[0048] [Chemistry 4]

[0049]

[0050] In the formula, R 5 , R 10 ~R 13 , L A , X L , Q 1 ~Q 3 and Z + Same as above;

[0051] n1 and n2 are each independently an integer from 0 to 4;

[0052] R 15 and R 16 Each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a hetero atom; and when n1 and n2 are 2 or more, a plurality of R 15 and R 16 They may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, or may be bonded to the carbon atoms to which they are bonded and the carbon atoms between them to form a ring.

[0053] 4. The onium salt of 3, which is represented by the following formula (1C);

[0054] [Chemistry 5]

[0055]

[0056] In the formula, R 5 , R10 ~R 13 , R 15 , R 16 , L A , X L and Z + Same as above.

[0057] 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);

[0058] [Chemistry 6]

[0059]

[0060] 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; and R ct1 and R ct2 They may also bond to each other to form a ring together with the sulfur atom to which they are bonded.

[0061] 6. A photoacid generator, which is composed of the onium salt according to any one of 1 to 5.

[0062] 7. A chemically amplified resist composition comprising the photoacid generator of 6.

[0063] 8. The chemically amplified resist composition of 7, comprising a base polymer containing a repeating unit represented by the following formula (a1);

[0064] [Chemistry 7]

[0065]

[0066] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0067] X 1 is a single bond, phenylene, naphthylene or *-C(=O)-OX 11 -, the phenylene 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. The saturated alkylene group may also 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;

[0068] AL 1 It is an acid-labile group.

[0069] 9. The chemically amplified resist composition of 8, wherein the base polymer comprises a repeating unit represented by the following formula (a2);

[0070] [Chemistry 8]

[0071]

[0072] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0073] X 2 is a single bond or *-C(=O)-O-; * represents an atomic bond to a carbon atom of the main chain;

[0074] 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 hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom;

[0075] AL 2 It is an acid-labile group;

[0076] a is an integer from 0 to 4.

[0077] 10. The chemically amplified resist composition of 8 or 9, wherein the base polymer comprises a repeating unit represented by the following formula (b1) or (b2);

[0078] [Chemistry 9]

[0079]

[0080] In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0081] Y 1 is a single bond or *-C(=O)-O-; * represents an atomic bond to a carbon atom of the main chain;

[0082] R 21 A group having 1 to 20 carbon atoms and 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)-);

[0083] R 22is 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 hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom;

[0084] b is an integer from 1 to 4; c is an integer from 0 to 4; but 1≤b+c≤5.

[0085] 11. The chemically amplified resist composition according to any one of 8 to 10, wherein the base polymer comprises 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);

[0086] [Chemistry 10]

[0087]

[0088] In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0089] Z 1 is a single bond or a phenylene group;

[0090] 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;

[0091] Z 3 Each is independently a single bond, phenylene, naphthylene or *-C(=O)-OZ 31 -;Z 31 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;

[0092] Z 4 Each is independently a single bond, **-Z 41 -C(=O)-O-, **-C(=O)-NH-Z 41 -or**-OZ 41 -;Z 41 is an alkylene group having 1 to 20 carbon atoms which may contain heteroatoms;

[0093] Z 5 Each is independently a single bond, *-Z51 -C(=O)-O-, *-C(=O)-NH-Z 51 -or*-OZ 51 -;Z 51 is an alkylene group having 1 to 20 carbon atoms which may contain heteroatoms;

[0094] 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 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;

[0095] * indicates an atomic bond to a carbon atom in the main chain; ** indicates an atomic bond to Z 3 Atomic bonds;

[0096] 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 With R 32 They may also bond to each other and form a ring together with the sulfur atom to which they are bonded;

[0097] 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;

[0098] R 1 and Rf 2 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms;

[0099] R 3 and Rf 4 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms;

[0100] R 5 and Rf 6 Each independently represents 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 Not all hydrogen atoms at the same time;

[0101] M - It is a non-nucleophilic counter ion;

[0102] A + is an onium cation;

[0103] d is an integer from 0 to 3.

[0104] 12. The chemically amplified resist composition according to any one of items 7 to 11, further comprising an organic solvent.

[0105] 13. The chemically amplified resist composition according to any one of items 7 to 12, further comprising a quencher.

[0106] 14. The chemically amplified resist composition according to any one of 7 to 13, further comprising a photoacid generator other than the photoacid generator according to 6.

[0107] 15. The chemically amplified resist composition according to any one of items 7 to 14, further comprising a surfactant.

[0108] 16. A method for forming a pattern, comprising the following steps:

[0109] A resist film is formed on a substrate using the chemically amplified resist composition of any one of items 7 to 15; the resist film is exposed to high-energy rays; and the exposed resist film is developed using a developer.

[0110] 17. The pattern forming method of 16, wherein the high-energy ray is KrF excimer laser, ArF excimer laser, EB or EUV with a wavelength of 3 to 15 nm.

[0111] [Effects of the Invention]

[0112] When a chemically amplified resist composition containing the onium salt of the present invention as a photoacid generator is used for pattern formation, high sensitivity and excellent acid diffusion inhibition ability are achieved, and lithography performance such as MEF and LWR is improved, and the collapse of the resist pattern during fine pattern formation can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0113] [ Figure 1 ] is the nuclear magnetic resonance spectrum of the onium salt PAG-1 synthesized in Example 1-1 ( 1 H-NMR / DMSO-d6). DETAILED DESCRIPTION

[0114] [Onium salt]

[0115] The onium salt of the present invention is represented by the following formula (1).

[0116] [Chemistry 11]

[0117]

[0118] In formula (1), R 1 ~R 12 Each R is independently a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom.13 and R 14 One of them is a group having a partial structure represented by the formula (1a) described later, and the other is a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom.

[0119] Examples of the halogen atom include fluorine, chlorine, bromine, and iodine atoms. 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 6 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.; and groups obtained by combining these. Among these, aryl groups are more preferred. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0120] Again, R 1 ~R 14At least two of them may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, or may form a ring together with the carbon atoms to which they are bonded and the carbon atoms between them. Specific examples of the ring formed at this time include alicyclic rings such as cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, norbornane ring, and adamantane ring, and aromatic rings such as benzene ring, naphthalene ring, and anthracene ring. In addition, part or all of the hydrogen atoms in the aforementioned ring may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of -CH2- in the aforementioned ring may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may also contain 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. Specific examples thereof include the following: 1 The hydrocarbon groups exemplified in the above are the same as those shown in the examples. The aforementioned ring is preferably an aromatic ring, and more preferably a benzene ring.

[0121] In formula (1), R 13 or R 14 Any of the following is a group having a partial structure represented by the following formula (1a). 14 It is preferably a group having a partial structure represented by the following formula (1a).

[0122] [Chemistry 12]

[0123]

[0124] In formula (1a), L A and L B Each independently represents a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a urethane bond. Among these, a single bond, an ether bond or an ester bond is more preferable.

[0125] In formula (1a), X L 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. Specific examples of the hetero atom include oxygen atoms, nitrogen atoms, sulfur atoms, etc.

[0126] Just X L Specific examples of the alkylene group having 1 to 40 carbon atoms which may contain a hetero atom as represented by the formula include those shown below, but are not limited to these. A and L B of atomic bonds.

[0127] [Chemistry 13]

[0128]

[0129] [Chemistry 14]

[0130]

[0131] [Chemistry 15]

[0132]

[0133] [Chemistry 16]

[0134]

[0135] Among these, X L -0~X L -22 and X L -47~X L -58 is ideal.

[0136] In formula (1a), Q 1 ~Q 3 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group is preferably a trifluoromethyl group.

[0137] In formula (1a), Q 1 and Q 2 When all are hydrogen atoms, Q 3 It is a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Among the fluorinated saturated hydrocarbon groups, a trifluoromethyl group is preferred.

[0138] In formula (1a), Q 1 ~Q 3 The total number of fluorine atoms in the onium salt must be 2 or more. This improves the solvent solubility of the onium salt and allows the onium salt to be uniformly dissolved in the resist solvent, thereby improving various lithography properties.

[0139] In formula (1a), -C(CF3)(Q 3 )-C(Q 1 )(Q 2 )-SO3 - As for the specific examples of the partial structure represented by, those shown below are preferred, but are not limited to these. In addition, in the following formula, * represents B of atomic bonds.

[0140] [Chemistry 17]

[0141]

[0142] Among these, Acid-1 and Acid-3 are more ideal from the perspective of synthesis. Acid-1 has an asymmetric carbon atom bonded to the trifluoromethyl group, so it produces diastereomers in the anion structure and improves solvent solubility. Although Acid-2 does not produce diastereomers like Acid-1, it improves solvent solubility by increasing the number of fluorine atoms.

[0143] The onium salt represented by the formula (1) is preferably represented by the following formula (1A).

[0144] [Chemistry 18]

[0145]

[0146] In the formula, R 1 ~R 13 , L A , X L , Q 1 ~Q 3 and Z + Same as above.

[0147] The onium salt represented by the formula (1A) is preferably represented by the following formula (1B).

[0148] [Chemistry 19]

[0149]

[0150] In the formula, R 5 , R 10 ~R 13 , L A , X L , Q 1 ~Q 3 and Z + Same as above.

[0151] In formula (1B), R 15 and R 16 Each is independently a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Specific examples of the halogen atom and the hydrocarbon group include: 1 ~R 14 The halogen atoms and hydrocarbon groups represented by are the same as those exemplified above.

[0152] In formula (1B), n1 and n2 are each independently an integer of 0 to 4. In particular, in view of the supply of raw materials, both are preferably 0 to 2.

[0153] In formula (1B), when n1 and n2 are 2 or more, multiple R 15 and R 16They may also be bonded to each other to form a ring together with the carbon atoms to which they are bonded, or to form a ring together with the carbon atoms to which they are bonded and the carbon atoms between them. Specific examples of the ring formed in this case include: 1 ~R 14 The examples of the ring that can be formed by at least two of them being bonded to each other are the same.

[0154] The onium salt represented by the formula (1B) is preferably represented by the following formula (1C).

[0155] [Chemistry 20]

[0156]

[0157] In the formula, R 5 , R 10 ~R 13 , R 15 , R 16 , L A , X L and Z + Same as above.

[0158] Specific examples of the anion of the onium salt represented by the formula (1) include those shown below, but are not limited to these. In the following formula, Me is a methyl group.

[0159] [Chemistry 21]

[0160]

[0161] [Chemistry 22]

[0162]

[0163] [Chemistry 23]

[0164]

[0165] [Chemistry 24]

[0166]

[0167] [Chemistry 25]

[0168]

[0169] [Chemistry 26]

[0170]

[0171] [Chemistry 27]

[0172]

[0173] [Chemistry 28]

[0174]

[0175] [Chemistry 29]

[0176]

[0177] [Chemistry 30]

[0178]

[0179] [Chemistry 31]

[0180]

[0181] [Chemistry 32]

[0182]

[0183] [Chemistry 33]

[0184]

[0185] [Chemistry 34]

[0186]

[0187] [Chemistry 35]

[0188]

[0189] [Chemistry 36]

[0190]

[0191] [Chemistry 37]

[0192]

[0193] 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).

[0194] [Chemistry 38]

[0195]

[0196] 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.

[0197] Just R ct1 ~Rct5 Examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0198] R ct1 ~R ct5 The hydrocarbon group represented by may be saturated or unsaturated, and may be any of straight chain, branched, and 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; and groups obtained by combining these groups, and aryl groups are more preferably aryl groups. 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, or a nitrogen atom. As a result, the hydrocarbon group 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.

[0199] Again, R ct1 and R ct2 They may be bonded to each other to 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.

[0200] [Chemistry 39]

[0201]

[0202] In the formula, the dotted line is the ct3 of atomic bonds.

[0203] Specific examples of the sulfonium cation represented by the formula (cation-1) include those shown below, but are not limited to these.

[0204] [Chemistry 40]

[0205]

[0206] [Chemistry 41]

[0207]

[0208] [Chemistry 42]

[0209]

[0210] [Chemistry 43]

[0211]

[0212] [Chemistry 44]

[0213]

[0214] [Chemistry 45]

[0215]

[0216] [Chemistry 46]

[0217]

[0218] [Chemistry 47]

[0219]

[0220] [Chemistry 48]

[0221]

[0222] [Chemistry 49]

[0223]

[0224] [Chemistry 50]

[0225]

[0226] [Chemistry 51]

[0227]

[0228] [Chemistry 52]

[0229]

[0230] [Chemistry 53]

[0231]

[0232] [Chemistry 54]

[0233]

[0234] [Chemistry 55]

[0235]

[0236] [Chemistry 56]

[0237]

[0238] [Chemistry 57]

[0239]

[0240] [Chemistry 58]

[0241]

[0242] [Chemistry 59]

[0243]

[0244] [Chemistry 60]

[0245]

[0246] [Chemistry 61]

[0247]

[0248] [Chemistry 62]

[0249]

[0250] [Chemistry 63]

[0251]

[0252] [Chemistry 64]

[0253]

[0254] [Chemistry 65]

[0255]

[0256] [Chemistry 66]

[0257]

[0258] Specific examples of the iodonium cation represented by the formula (cation-2) include those shown below, but are not limited to these.

[0259] [Chemistry 67]

[0260]

[0261] [Chemistry 68]

[0262]

[0263] Specific examples of the onium salt of the present invention include any combination of the above-mentioned anions and cations.

[0264] 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, but the synthesis method is not limited thereto.

[0265] [Chemistry 69]

[0266]

[0267] In the formula, R 1 ~R 13 , L A , X L , Q 1 ~Q 3 and Z + Same as above. + Is a relative cation. - is the relative anion.

[0268] The first step is a step of obtaining the intermediate In-1 by reacting a raw material SM-1 obtained by a commercial product or a known synthesis method with a raw material SM-2. When a direct ester bond is formed by the carboxyl group of the raw material SM-1 and the hydroxyl group of the raw material SM-2, various condensing agents can be used. As for the condensing agent used, N, N'-dicyclohexylcarbodiimide, N, N'-diisopropylcarbodiimide, 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide, hydrochloric acid 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, etc. can be cited, but considering the ease of removal of the urea compound generated as a by-product after the reaction, it is more ideal to use hydrochloric acid 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. The reaction is carried out by dissolving the raw materials SM-1 and 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, from the perspective of yield, is expected to be completed by tracking the reaction with silica gel thin layer chromatography (TLC), but it is usually about 12 to 24 hours. After the reaction is stopped, the by-produced urea compound is removed by filtration or water washing as needed, and the intermediate In-1 can be obtained by subjecting the reaction solution to a conventional aqueous work-up. The intermediate In-1 obtained can also be purified by general methods such as chromatography and recrystallization, if necessary.

[0269] The second step is to react the obtained intermediate In-1 with Z + X - The step of obtaining an onium salt (PAG-1-ex) by salt exchange with an onium salt (raw material SM-3) represented by X -Chloride ions, bromide ions, iodide ions or methylsulfate anions are more desirable because the exchange reaction can be easily carried out quantitatively. The progress of the reaction is considered from the perspective of yield, and it is desirable to confirm it by TLC. 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 general methods such as chromatography and recrystallization.

[0270] In the above scheme, the ion exchange in the second step can be easily performed by a known method, and for example, Japanese Patent Application Laid-Open No. 2007-145797 can be referred to.

[0271] In addition, the above-mentioned production method is only an example, and the production method of the onium salt of the present invention is not limited thereto.

[0272] As for the structural features of the onium salt of the present invention, examples include the introduction of a substituted ring-contracted structure and an alkanesulfonic acid structure containing a trifluoromethyl group with a fluorine number of 5 or more into anions. The substituted ring-contracted structure functions as a substituent with a large exclusion volume and a large steric hindrance, and the diffusion of the generated acid is highly suppressed. In addition, because it is resistant to alkaline developer, the film loss of the pattern of the unexposed portion is reduced. On the other hand, the alkanesulfonic acid structure containing a trifluoromethyl group with a fluorine number of 5 or more, while increasing the acidity of the generated acid and deprotecting the acid-labile group of the base polymer, will generate isomers in the anion by the carbon atom bonded to the trifluoromethyl group becoming an asymmetric carbon. While the crystallization energy of the target object is reduced by the generation of isomers, the solvent solubility is improved by the increase in the number of fluorine atoms. In addition, although the fluorine atom is not as good as the iodine atom, it is still an element with a high absorption effect of EUV light, so the generation of secondary electrons will increase by increasing the number of fluorine atoms, which will promote the decomposition of cations and contribute to high sensitivity. In Japanese Patent No. 7109178, alkanesulfonic acid-type photoacid generators with 2 to 4 fluorine atoms are proposed, but they do not generate isomers and have poor solvent solubility, so there is a concern about development defects. Since the number of fluorine atoms is less than that of the photoacid generator of the present invention, it can be expected that the contribution to high sensitivity is small. Due to their multiplication effect, the resist composition containing the onium salt of the present invention has high sensitivity and low acid diffusivity, so the LWR of the line pattern and the CDU of the hole pattern are excellent, and a pattern with strong resistance to pattern collapse can be formed, so it is ideal when forming a fine pattern.

[0273] The aforementioned onium salts can be preferably used as a photoacid generator.

[0274] [Chemically amplified resist composition]

[0275] [(A) Photoacid generator]

[0276] The chemically amplified resist composition of the present invention contains (A) a photoacid generator composed of an onium salt represented by the formula (1) as an essential component.

[0277] In the chemically amplified resist composition of the present invention, the content of the photoacid generator composed of the onium salt represented by formula (1) in 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) falls within the above range, the sensitivity and resolution are good, and there is no concern of foreign matter after the development or peeling of the resist film, so it is more ideal. The photoacid generator of component (A) can be used alone or in combination of two or more.

[0278] [(B) Base polymer]

[0279] The chemically amplified resist composition of the present invention may also contain a base polymer as the component (B). The base polymer (B) is a polymer containing a repeating unit represented by the following formula (a1) (hereinafter, also referred to as repeating unit a1).

[0280] [Chemistry 70]

[0281]

[0282] In formula (a1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0283] In formula (a1), X 1 is a single bond, phenylene, naphthylene or *-C(=O)-OX 11 -, 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. 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.

[0284] In formula (a1), AL 1 The acid-labile group includes those described in JP-A-2013-80033 and JP-A-2013-83821.

[0285] Representative examples of the acid-labile group include those represented by the following formulae (AL-1) to (AL-3).

[0286] [Chemistry 71]

[0287]

[0288] In the formula, the dotted lines are atomic bonds.

[0289] In formula (AL-1) and (AL-2), R L1 and R L2 Each 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 hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. The hydrocarbon group preferably has 1 to 20 carbon atoms.

[0290] In the formula (AL-1), k is an integer of 0-10, and preferably an integer of 1-5.

[0291] In formula (AL-2), R L3 and R L4 Each is independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and may also contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be any of linear, branched, and cyclic. As for the aforementioned hydrocarbon group, the one having 1 to 20 carbon atoms is more preferable. L2 , R L3 and R L4 Any two of them may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. The above ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0292] In formula (AL-3), 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 aforementioned hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. As for the aforementioned hydrocarbon group, the one having 1 to 20 carbon atoms is more preferable. L5 , R L6 and R L7 Any two of them may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded. The above-mentioned ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0293] Specific examples of the repeating unit a1 include those shown below, but are not limited to these. A and AL 1 Same as above.

[0294] [Chemistry 72]

[0295]

[0296] [Chemistry 73]

[0297]

[0298] [Chemistry 74]

[0299]

[0300] The aforementioned base polymer may further contain a repeating unit represented by the following formula (a2) (hereinafter, also referred to as repeating unit a2).

[0301] [Chemistry 75]

[0302]

[0303] In formula (a2), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 2 is a single bond or *-C(=O)-O-. * represents an atomic bond to 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 hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom. 2 The acid-labile group is an acid-labile group. 1 The acid-labile groups represented by are the same as those exemplified above. a is an integer of 0 to 4, and is preferably 0 or 1.

[0304] Specific examples of the repeating unit a2 include those shown below, but are not limited to these. A and AL 2 Same as above.

[0305] [Chemistry 76]

[0306]

[0307] [Chemistry 77]

[0308]

[0309] The base polymer preferably further includes 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).

[0310] [Chemistry 78]

[0311]

[0312] In formula (b1) and (b2), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 is a single bond or *-C(=O)-O-. * represents an atomic bond to a carbon atom of the main chain. 21 It is a hydrogen atom, or a group having 1 to 20 carbon atoms containing a structure including 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)-). 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 hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl 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.

[0313] Specific examples of the repeating unit b1 include those shown below, but are not limited to these. A Same as above.

[0314] [Chemistry 79]

[0315]

[0316] [Chemistry 80]

[0317]

[0318] [Chemistry 81]

[0319]

[0320] [Chemistry 82]

[0321]

[0322] [Chemistry 83]

[0323]

[0324] [Chemistry 84]

[0325]

[0326] [Chemistry 85]

[0327]

[0328] [Chemistry 86]

[0329]

[0330] [Chemistry 87]

[0331]

[0332] [Chemistry 88]

[0333]

[0334] [Chemistry 89]

[0335]

[0336] [Chemistry 90]

[0337]

[0338] [Chemistry 91]

[0339]

[0340] [Chemistry 92]

[0341]

[0342] [Chemistry 93]

[0343]

[0344] [Chemistry 94]

[0345]

[0346] Specific examples of the repeating unit b2 include those shown below, but are not limited to these. A Same as above.

[0347] [Chemistry 95]

[0348]

[0349] [Chemistry 96]

[0350]

[0351] [Chemistry 97]

[0352]

[0353] [Chemistry 98]

[0354]

[0355] [Chemistry 99]

[0356]

[0357] As for the repeating unit b1 or b2, in ArF lithography, those having a lactone ring as a polar group are more preferable, and in KrF lithography, EB lithography and EUV lithography, those having a phenol part are more preferable.

[0358] The aforementioned base polymer may also 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).

[0359] [Chemical 100]

[0360]

[0361] In formulas (c1) to (c4), R A are each 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 Each is independently a single bond, phenylene, naphthylene 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 Each is independently a single bond, **-Z 41 -C(=O)-O-, **-C(=O)-NH-Z 41 -or**-OZ 41 -.Z 41 It is a alkylene group having 1 to 20 carbon atoms which may contain a hetero atom. 5 Each is independently a single bond, *-Z 51 -C(=O)-O-, *-C(=O)-NH-Z 51 -or*-OZ 51 -.Z 51 It is a alkylene group having 1 to 20 carbon atoms which may contain a hetero atom. 6is 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, phenylene group, fluorinated phenylene group or phenylene group substituted with trifluoromethyl group having 1 to 6 carbon atoms, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group. * indicates an atomic bond to a carbon atom of the main chain. ** indicates an atomic bond to Z 3 of atomic bonds.

[0362] Z 21 , Z 31 and Z 61 The aliphatic alkylene group represented may be any of linear, branched or cyclic, and specific examples thereof include alkanediyl groups such as methanediyl, ethane-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.

[0363] 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 to these.

[0364] [Chemistry 101]

[0365]

[0366] In the formula, the dotted lines are atomic bonds.

[0367] In formula (c1), R 31 and R 32Each independently represents a hydrocarbon group having 1 to 20 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 alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl; 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 6 to 20 carbon atoms, such as phenyl, naphthyl, thienyl, etc.; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, 2-phenylethyl, etc.; and groups obtained by combining these, but aryl groups are more desirable. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. 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.

[0368] Again, R 31 and R 32 They may also be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring may be exemplified by the same as in the description of formula (cation-1) with respect to R ct1 and R ct2 The rings that can be formed by bonding with the sulfur atom to which they are bonded are the same as those exemplified above.

[0369] Specific examples of the cation in the repeating unit c1 include those shown below, but are not limited to these. A Same as above.

[0370] [Chemistry 102]

[0371]

[0372] [Chemistry 103]

[0373]

[0374] [Chemistry 104]

[0375]

[0376] [Chemistry 105]

[0377]

[0378] [Chemistry 106]

[0379]

[0380] [Chemistry 107]

[0381]

[0382] [Chemistry 108]

[0383]

[0384] In formula (c1), M - It is a non-nucleophilic relative ion. As for the aforementioned non-nucleophilic relative ions, halide ions, sulfonic acid anions, imidic acid anions and methylated acid anions are more ideal. As for the specific examples of the aforementioned halide ions, chloride ions, bromide ions, etc. can be cited. As for the specific examples of the aforementioned sulfonic acid anions (sulfonate ions), fluoroalkyl sulfonate ions such as trifluoromethanesulfonate ions, 1,1,1-trifluoroethanesulfonate ions, nonafluorobutanesulfonate ions; aryl sulfonate ions such as toluenesulfonate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, 1,2,3,4,5-pentafluorobenzenesulfonate ions; alkyl sulfonate ions such as methanesulfonate ions and butanesulfonate ions, etc. can be cited. Specific examples of the aforementioned imidic acid anions (imide ions) include bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, bis(perfluorobutylsulfonyl)imide ions, etc. Specific examples of the aforementioned methylated acid anions (methide ions) include imide ions such as bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, bis(perfluorobutylsulfonyl)imide ions; tris(trifluoromethylsulfonyl)methide ions, tris(perfluoroethylsulfonyl)methide ions, etc.

[0385] Other examples of the non-nucleophilic counter ion include anions represented by any of the following formulae (c1-1) to (c1-4).

[0386] [Chemistry 109]

[0387]

[0388] 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 the following: fa1 The hydrocarbon groups exemplified are the same as those exemplified above.

[0389] The anion represented by the formula (c1-1) is preferably an anion represented by the following formula (c1-1-1).

[0390] [Chemistry 110]

[0391]

[0392] In formula (c1-1-1), Q 11 and Q 12 Each of them is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, but at least one of them is preferably a trifluoromethyl group in order to improve solvent solubility. m is an integer of 0 to 4, and is particularly preferably 1. fa1 The 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 preferably one having 6 to 30 carbon atoms from the viewpoint of obtaining a high resolution in fine pattern formation.

[0393] 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; and groups obtained by combining these.

[0394] 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. may be contained. 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.

[0395] 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, an ether bond or an ester bond is more preferable, and an ester bond is more preferable.

[0396] Specific examples of the anion represented by formula (c1-1) include those shown below, but are not limited to these. 11 As mentioned above, Ac is acetyl.

[0397] [Chemistry 111]

[0398]

[0399] [Chemistry 112]

[0400]

[0401] [Chemistry 113]

[0402]

[0403] [Chemistry 114]

[0404]

[0405] [Chemistry 115]

[0406]

[0407] [Chemistry 116]

[0408]

[0409] [Chemistry 117]

[0410]

[0411] [Chemistry 118]

[0412]

[0413] [Chemistry 119]

[0414]

[0415] [Chemistry 120]

[0416]

[0417] 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 straight-chain, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are the same as those exemplified above. fb1 and R fb2 In particular, R 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 they bond to (-CF2-SO2-N - -SO2-CF2-) together to form a ring, at this time, R fb1 and R fb2 As the groups that can be bonded to each other, fluorinated ethylene groups or fluorinated propylene groups are preferred.

[0418] 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 straight-chain, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are the same as those exemplified above. fc1 , R fc2 and R fc3 In particular, R 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 they bond to (-CF2-SO2-C - -SO2-CF2-) together to form a ring, at this time, R fc1 and R fc2The groups that can be obtained by bonding to each other are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0419] 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 straight chain, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups exemplified are the same as those exemplified above.

[0420] Specific examples of the anion represented by the formula (c1-4) include those shown below, but are not limited to these.

[0421] [Chemistry 121]

[0422]

[0423] [Chemistry 122]

[0424]

[0425] Examples of the non-nucleophilic counter ions 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).

[0426] [Chemistry 123]

[0427]

[0428] 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.

[0429] 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.

[0430] In formula (c1-5), L 11 It is a single bond, an ether bond, or an ester bond, or a saturated alkylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated alkylene group may be linear, branched, or cyclic.

[0431] In formula (c1-5), L 12 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.

[0432] 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 hydrocarbonoxy group having 1 to 20 carbon atoms, a hydrocarboncarbonyl group having 2 to 20 carbon atoms, a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms or a hydrocarbonsulfonyloxy 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 Each 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 carbonyloxy group having 2 to 6 carbon atoms. feD It 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 any of a straight chain, a branched shape, or a cyclic shape. The aforementioned hydrocarbon group, hydrocarbon oxy group, hydrocarbon carbonyl group, hydrocarbon oxycarbonyl group, hydrocarbon carbonyloxy group, and hydrocarbon sulfonyloxy group may be any of a straight chain, a branched shape, or a cyclic shape. When x and / or z is 2, each R fe They can be the same or different.

[0433] Among these, R fe For 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 are preferred.

[0434] In formula (c1-5), Rf 11 ~Rf 14 Each independently represents 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 and Rf 12 They can also combine to form a carbonyl group. 13 and Rf 14 It is particularly preferred that they are fluorine atoms at the same time.

[0435] Specific examples of the anion represented by formula (c1-5) include those shown below, but are not limited to these. BI Same as above.

[0436] [Chemistry 124]

[0437]

[0438] [Chemistry 125]

[0439]

[0440] [Chemistry 126]

[0441]

[0442] [Chemistry 127]

[0443]

[0444] [Chemistry 128]

[0445]

[0446] [Chemistry 129]

[0447]

[0448] [Chemistry 130]

[0449]

[0450] [Chemistry 131]

[0451]

[0452] [Chemistry 132]

[0453]

[0454] [Chemistry 133]

[0455]

[0456] [Chemistry 134]

[0457]

[0458] [Chemistry 135]

[0459]

[0460] [Chemistry 136]

[0461]

[0462] [Chemistry 137]

[0463]

[0464] [Chemistry 138]

[0465]

[0466] [Chemistry 139]

[0467]

[0468] [Chemistry 140]

[0469]

[0470] [Chemistry 141]

[0471]

[0472] [Chemistry 142]

[0473]

[0474] [Chemistry 143]

[0475]

[0476] [Chemistry 144]

[0477]

[0478] [Chemistry 145]

[0479]

[0480] [Chemistry 146]

[0481]

[0482] As for the aforementioned non-nucleophilic counter ion, 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 and Japanese Patent Application No. 2021-70692, an anion having a cyclic ether group described in Japanese Patent Application No. 2018-180525 and Japanese Patent Application No. 2021-35935, and an anion described in Japanese Patent Application No. 2018-92159 can also be used.

[0483] As for the aforementioned non-nucleophilic counter ions, anions of fluorine-free, bulky benzenesulfonic acid derivatives described in JP-A-2006-276759, JP-A-2015-117200, JP-A-2016-65016, and JP-A-2019-202974, and fluorine-free benzenesulfonic acid anions and alkylsulfonic acid anions bonded to an aromatic group containing an iodine atom described in JP-A-6645464 can also be used.

[0484] As for the aforementioned non-nucleophilic counter ion, the anion of the disulfonic acid described in JP-A-2015-206932, the anion of a sulfonic acid on one side and a sulfonamide or sulfonimide different therefrom on the other side described in International Publication No. 2020 / 158366, and the anion of a sulfonic acid on one side and a carboxylic acid on the other side described in JP-A-2015-24989 can also be used.

[0485] 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 more preferable, and an ester bond or a carbonyl group is more preferable.

[0486] In formula (c2), Rf 1 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 more ideal that all of them are fluorine atoms. 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. 3 and Rf 4 It is preferred that at least one of the groups is a trifluoromethyl group.

[0487] In formula (c3), Rf 5 and Rf 6 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 5 and Rf 6 They are not hydrogen atoms at the same time. Among them, in order to improve the solvent solubility, Rf 5 and Rf 6 It is preferred that at least one of the groups is a trifluoromethyl group.

[0488] In formulae (c2) and (c3), d is an integer of 0 to 3, and 1 is preferable.

[0489] Specific examples of the anion of the repeating unit c2 include those shown below, but are not limited to these. A As mentioned above, Me is methyl.

[0490] [Chemistry 147]

[0491]

[0492] [Chemistry 148]

[0493]

[0494] [Chemistry 149]

[0495]

[0496] [Chemistry 150]

[0497]

[0498] [Chemistry 151]

[0499]

[0500] [Chemistry 152]

[0501]

[0502] [Chemistry 153]

[0503]

[0504] [Chemistry 154]

[0505]

[0506] [Chemistry 155]

[0507]

[0508] Specific examples of the anion of the repeating unit c3 include those shown below, but are not limited to these. A Same as above.

[0509] [Chemistry 156]

[0510]

[0511] [Chemistry 157]

[0512]

[0513] [Chemistry 158]

[0514]

[0515] [Chemistry 159]

[0516]

[0517] [Chemistry 160]

[0518]

[0519] [Chemistry 161]

[0520]

[0521] [Chemistry 162]

[0522]

[0523] [Chemistry 163]

[0524]

[0525] Specific examples of the anion of the repeating unit c4 include those shown below, but are not limited to these. A Same as above.

[0526] [Chemistry 164]

[0527]

[0528] In formulas (c2) to (c4), A + Onium cations. Examples of the onium cations include ammonium cations, sulfonium cations, and iodonium cations, but sulfonium cations and iodonium cations are more preferred. Specific examples thereof include those exemplified for the sulfonium cations represented by formula (cation-1) and the iodonium cations represented by formula (cation-2), and those exemplified for the ammonium cations represented by formula (cation-3) described later, but are not limited thereto.

[0529] As specific structures of the repeating units c1 to c4, any combination of anions and cations as described above can be mentioned.

[0530] Among repeating units c1 to c4, repeating units c2, c3 and c4 are more preferable from the viewpoint of controlling acid diffusion, repeating units c2 and c4 are more preferable from the viewpoint of acid strength of the generated acid, and repeating unit c2 is more preferable from the viewpoint of solvent solubility.

[0531] 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). The repeating unit d is not particularly limited as long as it has a structure in which one or two hydroxyl groups are protected and the protecting group decomposes due to the action of an acid to generate a hydroxyl group, but the repeating unit d is preferably represented by the following formula (d1).

[0532] [Chemistry 165]

[0533]

[0534] 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.

[0535] 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 particularly preferably an alkoxymethyl group represented by the following formula (d2).

[0536] [Chemistry 166]

[0537]

[0538] In the formula, * represents an atomic bond. 43 It is a hydrocarbon group having 1 to 15 carbon atoms.

[0539] Just 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 ones as exemplified in the description of the repeating unit d described in JP-A-2020-111564.

[0540] 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 those shown below, but are not limited thereto.

[0541] [Chemistry 167]

[0542]

[0543] The aforementioned base polymer may further contain a repeating unit f derived from indane, vinylpyridine or vinylcarbazole.

[0544] In the polymer of the present invention, the content ratios of the 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.

[0545] The weight average molecular weight (Mw) of the aforementioned polymer is preferably 1000 to 500000, and more preferably 3000 to 100000. If Mw falls within this range, sufficient etching resistance can be obtained, and there is no concern about a decrease in resolution due to the inability to ensure a difference in dissolution rate before and after exposure. In addition, in the present invention, Mw is a polystyrene conversion measurement value obtained by a gel permeation chromatograph (GPC) using THF or N,N-dimethylformamide (DMF) as a solvent.

[0546] Then, regarding the molecular weight distribution (Mw / Mn) of the aforementioned polymer, since the influence of Mw / Mn tends to become larger as the pattern rule is miniaturized, in order to obtain a resist composition that can be ideally used for fine pattern sizes, a narrow dispersion with Mw / Mn of 1.0 to 2.0 is preferable. If it falls within the above range, there are fewer low molecular weight and high molecular weight polymers, and there is no concern about finding foreign substances on the pattern or deterioration of the pattern shape after exposure.

[0547] To synthesize the aforementioned polymer, for example, the monomers providing the repeating units can be added with a radical polymerization initiator in an organic solvent and heated to carry out polymerization.

[0548] As for the organic solvent used in the polymerization, toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL) and the like can be cited. As for the above-mentioned polymerization initiator, 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 and the like can be cited. 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.

[0549] The aforementioned polymerization initiator can be added to the aforementioned monomer solution and supplied to the reactor, or the initiator solution can be prepared separately from the aforementioned monomer solution and then independently supplied to the reactor. During the standby time, there is a possibility that the polymerization reaction will be carried out due to the free radicals generated from the initiator and an ultra-high molecular body will be generated. Therefore, considering the viewpoint of quality management, it is more ideal that the monomer solution and the initiator solution are independently prepared and added dropwise. The acid-labile group can also be directly used by introducing it into the monomer, or it can be protected or partially protected after polymerization. In addition, for the adjustment of molecular weight, a known chain transfer agent such as dodecanethiol and 2-mercaptoethanol can also be used in combination. At this time, the addition amount of these chain transfer agents relative to the total amount of the monomers to be polymerized is preferably 0.01 to 20 mol%.

[0550] When the monomer contains a hydroxyl group, the hydroxyl group may be replaced with an acetal group such as ethoxyethoxy which is easily deprotected by acid during polymerization and then deprotected by 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 alkali after polymerization.

[0551] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, a free radical polymerization initiator is added to hydroxystyrene or hydroxyvinylnaphthalene and other monomers in an organic solvent and the polymerization is carried out by heating. However, acetoxystyrene or acetoxyvinylnaphthalene can also be used and the acetoxy group can be deprotected by alkaline hydrolysis after polymerization to produce polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0552] As the base for alkaline hydrolysis, aqueous ammonia, triethylamine, etc. can be used. 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.

[0553] The amount of each monomer in the monomer solution can be appropriately set, for example, so as to achieve the preferred content ratio of the repeating unit.

[0554] The polymer obtained by the above-mentioned production method can be a reaction solution obtained by the polymerization reaction as the final product, or a powder obtained by adding the polymerization solution to a poor solvent and treating it as the final product through a purification step such as a reprecipitation method to obtain a powder. However, considering the operating efficiency and quality stability, it is more ideal to treat the powder obtained by the purification step into a solvent to form a polymer solution as the final product.

[0555] 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 ether, 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.

[0556] 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.

[0557] It is preferable to filter the reaction solution and polymer solution through a filter medium. By filtering through a filter medium, foreign matter and gel that may cause defects can be removed, which is effective in stabilizing quality.

[0558] As for the material of the filter material used in the aforementioned filter material filtration, materials such as fluorocarbon, cellulose, nylon, polyester, hydrocarbon can be cited, but in the filtering step of the resist composition, the filter material formed by hydrocarbons such as fluorocarbon, polyethylene, polypropylene or nylon called Teflon (registered trademark) is more ideal. The pore size of the filter material can be appropriately selected in conjunction with the cleanliness set as the target, but it is more ideal to be less than 100nm, and more ideal to be less than 20nm. Again, these filter materials can be used alone, or a variety of filter materials can be used in combination. As for the filtering method, the solution can be made to pass only once, but it is more ideal to circulate the solution and filter multiple times. The filtering step can be carried out in any order and number of times in the manufacturing step of the polymer, but it is more ideal to filter the reaction solution, polymer solution or both after the polymerization reaction.

[0559] 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 contain a hydrogenated ring-opening metathesis polymer in addition to the aforementioned polymers, and the polymer described in Japanese Patent Application Publication No. 2003-66612 may be used.

[0560] [(C) Organic solvent]

[0561] 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 above-mentioned components and the components described below. As for such organic solvents, there can be listed 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; ketoalcohols 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 mono-tert-butyl ether acetate; lactones such as GBL; mixed solvents thereof, etc.

[0562] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixed solvents thereof are preferred because they have particularly excellent solubility in the base polymer of the component (B).

[0563] 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.

[0564] [(D) Quencher]

[0565] The chemically amplified resist composition of the present invention may also contain a quencher as component (D). In addition, the quencher in the present invention refers to a material used to form a desired pattern by capturing the acid generated from the photoacid generator in the chemically amplified resist composition and preventing it from diffusing to the unexposed area.

[0566] Examples of the quencher (D) include onium salts represented by the following formula (2) or (3).

[0567] [Chemistry 168]

[0568]

[0569] In formula (2), R q1 is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom, but excludes a case where the hydrogen atom bonded to the carbon atom at the α-position of the sulfonic acid group is substituted with a fluorine atom or a fluoroalkyl group. q2 It is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom.

[0570] Just R q1 Specific examples of the hydrocarbon group having 1 to 40 carbon atoms include 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 with 3 to 40 carbon atoms such as decyl and adamantyl; aryl groups with 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 -CH2- of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. 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.

[0571] Just R q2 Specifically, in addition to R q1 In addition to the substituents exemplified in the specific examples of , fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl can be mentioned.

[0572] Specific examples of the anion of the onium salt represented by the formula (2) include those shown below, but are not limited to these.

[0573] [Chemistry 169]

[0574]

[0575] [Chemistry 170]

[0576]

[0577] [Chemistry 171]

[0578]

[0579] [Chemistry 172]

[0580]

[0581] Specific examples of the anion of the onium salt represented by the formula (3) include those shown below, but are not limited to these.

[0582] [Chemistry 173]

[0583]

[0584] [Chemistry 174]

[0585]

[0586] [Chemistry 175]

[0587]

[0588] In formula (2) and (3), 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).

[0589] [Chemistry 176]

[0590]

[0591] In formula (cation-3), R ct6 ~R ct9 are each independently a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. ct6 and R ct7 They may also be bonded to each other to form a ring together with the nitrogen atom to which they are bonded. As the aforementioned hydrocarbon group, examples thereof include those mentioned above with respect to R in the description of formula (cation-1) and (cation-2):ct1 ~R ct5 The hydrocarbon groups exemplified are the same as those exemplified above.

[0592] Specific examples of the ammonium cation represented by the formula (cation-3) include those shown below, but are not limited to these.

[0593] [Chemistry 177]

[0594]

[0595] As for the specific example of the onium salt represented by formula (2) or (3), any combination of the above-mentioned anions and cations can be cited. In addition, these onium salts are easily prepared by ion exchange reactions using known organic chemical methods. Regarding ion exchange reactions, for example, Japanese Patent Publication No. 2007-145797 can be used as a reference.

[0596] The onium salt represented by formula (2) or (3) functions as a quencher in the chemically amplified resist composition of the present invention. This is because each counter anion of the onium salt is a conjugate base of a weak acid. Here, the so-called weak acid refers to an acid that is insufficient to deprotect the acid-labile group of the unit containing an acid-labile group used in the base polymer. The onium salt represented by formula (2) or (3) functions as a quencher when used in combination with an onium salt-type photoacid generator having a conjugate base of a strong acid such as sulfonic acid fluorinated at the α-position as a counter anion. That is, when an onium salt that generates a strong acid such as sulfonic acid fluorinated at the α-position is used in combination with an onium salt that generates a weak acid such as sulfonic acid or carboxylic acid that is not fluorinated, if the strong acid generated from the photoacid generator due to high-energy ray irradiation collides with the unreacted onium salt having a weak acid anion, the weak acid is released due to salt exchange, and an onium salt having a strong acid anion is generated. Through this process, the strong acid is exchanged for a weaker acid with lower catalytic ability, so the acid is apparently deactivated and the acid diffusion can be controlled.

[0597] In addition, as for the quencher (D), an onium salt having a sulfonium cation and a phenoxide anion site in the same molecule as described in Japanese Patent No. 6848776 can be used, and 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 Publication 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 can also be used.

[0598] Here, when the photoacid generator that generates a strong acid is an onium salt, it is considered that, although the strong acid generated by high-energy ray irradiation is exchanged for a weak acid as described above, on the other hand, the weak acid generated by high-energy ray irradiation and the unreacted onium salt that generates a strong acid collide with each other, making it difficult to exchange salts. This is because the onium cation easily forms an ion pair with the anion of a stronger acid.

[0599] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (2) or (3) as the (D) quencher, 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 (B) base polymer. If the onium salt quencher of the (D) component falls within the above range, the resolution is good and there is no significant decrease in sensitivity, so it is more ideal. The onium salt represented by formula (2) or (3) can be used alone or in combination of two or more.

[0600] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as (D) a quencher. As for the nitrogen-containing compound of the component (D), examples thereof include primary, secondary or tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Publication 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 thereof include compounds described in Japanese Patent No. 3790649, and compounds obtained by protecting primary or secondary amines with carbamate groups.

[0601] In addition, a sulfonium sulfonate salt having a nitrogen-containing substituent may be used as a nitrogen-containing compound. This compound functions as a quencher in the unexposed part, and the exposed part loses the quencher performance due to neutralization with the acid generated by itself, and functions 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. As for the photodisintegration base, for example, Japanese Patent Publication No. 2009-109595, Japanese Patent Publication No. 2012-46501, etc. can be used as reference.

[0602] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as the (D) quencher, its content 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 (B) base polymer. The nitrogen-containing compound may be used alone or in combination of two or more.

[0603] [(E) Other photoacid generators]

[0604] The chemically amplified resist composition of the present invention may also contain a photoacid generator other than the component (A) (hereinafter, also referred to as other photoacid generator) as the component (E). The other photoacid generator is not particularly limited as long as it is a compound that generates acid when irradiated with high-energy rays. As for the ideal other photoacid generator, those represented by the following formula (4) or (5) can be cited.

[0605] [Chemistry 178]

[0606]

[0607] In formula (4), 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 to form a ring together with the sulfur atom to which they are bonded. As for the aforementioned hydrocarbon group, examples thereof include the following with respect to R in the description of formula (cation-1) and (cation-2): ct1 ~R ct5 The hydrocarbon groups exemplified are the same as those exemplified above.

[0608] Specific examples of the cation of the sulfonium salt represented by formula (4) include the same ones as those exemplified for the sulfonium cation represented by formula (cation-1). Specific examples of the cation of the iodonium salt represented by formula (5) include the same ones as those exemplified for the iodonium cation represented by formula (cation-2).

[0609] In formula (4) and (5), Xa - It is an anion of a strong acid. Examples of the anion of a strong acid include those represented by any of formulae (c1-1) to (c1-5).

[0610] Moreover, as for the other photo-acid generator of the component (E), it is also preferable that it is represented by the following formula (6).

[0611] [Chemistry 179]

[0612]

[0613] In formula (6), R 201 and R 202 Each independently represents 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 to form a ring together with the sulfur atom to which they are bonded.

[0614] R 201 and R 202 The 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, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl and anthracenyl; groups derived from combinations thereof, etc. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0615] R 203The alkylene group having 1 to 30 carbon atoms represented by the 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. -diyl, heptadecanediyl, etc.; alkylene groups having 1 to 30 carbon atoms, such as cyclopentanediyl, cyclohexanediyl, norbornanediyl, and adamantanediyl; arylene groups 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. As for the aforementioned hetero atom, an oxygen atom is preferably used.

[0616] In formula (6), L A 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 straight chain, branched, or cyclic. Specific examples thereof include: 203 The alkylene groups exemplified are the same as those exemplified above.

[0617] In formula (6), X a , X b , X c and X d Each independently represents 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.

[0618] The photoacid generator represented by the formula (6) is preferably represented by the following formula (6').

[0619] [Chemistry 180]

[0620]

[0621] In formula (6'), L A 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 straight chain, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are the same as those exemplified above. p and q are each independently an integer of 0-5, and r is an integer of 0-4.

[0622] Examples of the photo-acid generator represented by formula (6) include the same ones as exemplified for the photo-acid generator represented by formula (2) in JP-A-2017-26980.

[0623] Among the other photoacid generators mentioned above, 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 (6') are particularly preferred because they have extremely low acid diffusion.

[0624] When the chemically amplified resist composition of the present invention contains (E) other photoacid generators, the content thereof is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass, relative to 80 parts by mass of the base polymer (B). If the amount of the photoacid generator of the component (E) added falls within the aforementioned range, the resolution is good, and there is no concern that foreign matter will occur after the development or peeling of the resist film, so it is more ideal. (E) Other photoacid generators can be used alone or in combination of two or more.

[0625] [(F) Surfactant]

[0626] The chemically amplified resist composition of the present invention may further contain a surfactant as the (F) component. As for the (F) surfactant, it 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. For such surfactants, reference may be made to those described in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2011-16746.

[0627] As for the surfactants that are insoluble or poorly soluble in water and alkali developer, among the surfactants described in the aforementioned gazette, FC-4430 (manufactured by 3M Co., Ltd.), 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 the oxetane ring-opening polymer represented by the following formula (surf-1) are particularly preferable.

[0628] [Chemistry 181]

[0629]

[0630] 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. As for the aforementioned aliphatic group, for a divalent one, ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentylene, etc. can be listed, and for a trivalent or tetravalent one, the following can be listed.

[0631] [Chemistry 182]

[0632]

[0633] In the formula, the dotted lines are atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.

[0634] Among these, 1,4-butylene group, 2,2-dimethyl-1,3-propylene group and the like are particularly preferred.

[0635] 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.

[0636] A surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer has the function of reducing water penetration and leaching by being aligned to the surface of the resist film when no resist protective film is used in ArF immersion lithography. Therefore, it is useful in terms of suppressing the dissolution of water-soluble components from the resist film and reducing damage to the exposure device. In addition, it is useful because it is soluble during development with an alkaline aqueous solution after exposure or after post-exposure baking (PEB) and is not likely to become a foreign matter that may cause defects. This type of surfactant is insoluble or poorly soluble in water and soluble in an alkaline developer. It is a polymer-type surfactant, also known as a hydrophobic resin, and is particularly ideal for having high water repellency and improved water sliding properties.

[0637] Specific examples of such polymeric surfactants include those containing at least one repeating unit selected from any one of the following formulae (7A) to (7E).

[0638] [Chemistry 183]

[0639]

[0640] In formulas (7A) to (7E), 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 Each R is 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 Each R is 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, there may be an ether bond or a carbonyl group 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 each 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 present between carbon-carbon bonds.

[0641] R s1The hydrocarbon group having 1 to 10 carbon atoms represented by , is preferably 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; and cyclic saturated hydrocarbon groups having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl. Among these, those having 1 to 6 carbon atoms are more preferred.

[0642] R s2 The alkylene group represented by is preferably a saturated alkylene group, and may be any of a linear, branched, or cyclic type. Specific examples thereof include methylene, ethylene, propylene, butylene, and pentylene.

[0643] 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, alkenyl groups, alkynyl groups, and other aliphatic unsaturated hydrocarbon groups, but saturated hydrocarbon groups are more preferred. s1 In addition to the hydrocarbon groups exemplified above, examples include undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and the like. s3 or R s6 As for the fluorinated hydrocarbon groups represented by , some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon groups are substituted with fluorine atoms. As mentioned above, these carbon-carbon bonds may be separated by ether bonds or carbonyl groups.

[0644] Just 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 in which each alkyl group is an alkyl group having 1 to 6 carbon atoms, and alkyl groups containing an oxo group having 4 to 20 carbon atoms.

[0645] 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 removing u hydrogen atoms from the above-mentioned hydrocarbon group or fluorinated hydrocarbon group.

[0646] R saThe fluorinated hydrocarbon group represented by 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 above-mentioned hydrocarbon groups are substituted with fluorine atoms. 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, and 2-(perfluorodecyl)ethyl.

[0647] Specific examples of the repeating unit represented by any of the formulae (7A) to (7E) include those shown below, but are not limited to these. B Same as above.

[0648] [Chemistry 184]

[0649]

[0650] [Chemistry 185]

[0651]

[0652] [Chemistry 186]

[0653]

[0654] [Chemistry 187]

[0655]

[0656] [Chemistry 188]

[0657]

[0658] [Chemistry 189]

[0659]

[0660] The aforementioned polymeric surfactant may further contain other repeating units other than the repeating units represented by formulas (7A) to (7E). As for other repeating units, examples include repeating units obtained from methacrylic acid, α-trifluoromethylacrylic acid derivatives, etc. In the polymeric surfactant, the content of the repeating units represented by formulas (7A) to (7E) is preferably 20 mol% or more, more preferably 60 mol% or more, and even more preferably 100 mol% in the total repeating units.

[0661] The Mw of the 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.

[0662] As for the method of synthesizing the aforementioned polymer surfactant, there can be cited a method in which a monomer having an unsaturated bond that provides a repeating unit represented by formula (7A) to (7E) and other repeating units as required is added with a free radical initiator to an organic solvent and heated to polymerize it. As for the organic solvent used in the polymerization, there can be cited toluene, benzene, THF, diethyl ether, dioxane, etc. As for the polymerization initiator, there can be cited to be AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), 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 can be used directly introduced into the monomer, or it can be protected or partially protected after polymerization.

[0663] When synthesizing the aforementioned polymer surfactant, a known chain transfer agent such as dodecanethiol 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.

[0664] 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, and 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 fine pattern formed will be sufficiently ensured. The surfactant (F) may be used alone or in combination of two or more.

[0665] [(G) Other ingredients]

[0666] The chemically amplified resist composition of the present invention may contain, as for (G) other components, a compound that decomposes by acid and generates acid (acid multiplication compound), an organic acid derivative, a fluorinated 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. For the aforementioned acid multiplication compound, reference may be made to the compounds described in Japanese Patent Application Laid-Open No. 2009-269953 or Japanese Patent Application Laid-Open No. 2010-215608. When the aforementioned acid multiplication compound is included, its content is preferably 0 to 5 parts by weight, and more preferably 0 to 3 parts by weight relative to 80 parts by weight of the (B) base polymer. If the content is too high, it is difficult to control the diffusion of the acid, and there is a possibility that the resolution and pattern shape may be deteriorated. For the aforementioned organic acid derivative, fluorinated alcohol and dissolution inhibitor, reference may be made to the compounds described in Japanese Patent Application Laid-Open No. 2009-269953 or Japanese Patent Application Laid-Open No. 2010-215608.

[0667] [Pattern Formation Method]

[0668] The pattern forming method of the present invention comprises the following steps: forming a resist film on a substrate using the chemically amplified resist composition; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

[0669] As for the aforementioned substrate, 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.) can be used.

[0670] The resist film can be formed, for example, by applying the chemically amplified resist composition onto a substrate by spin coating or the like so that the film thickness is preferably 0.05 to 2 μm, and pre-baking the film on a hot plate at a temperature of preferably 60 to 150° C. for 1 to 10 minutes, more preferably 80 to 140° C. for 1 to 5 minutes.

[0671] As for the high energy radiation used for exposure of the resist film, for example, KrF excimer laser, ArF excimer laser, EB, EUV, etc. can be cited. When using KrF excimer laser, ArF excimer laser or EUV, a mask for forming a target pattern can be used and the exposure amount is preferably 1 to 200 mJ / cm 2 , more preferably 10 to 100 mJ / cm 2 When using EB, a mask for forming the target pattern or directly using an exposure dose of 1 to 300 μC / cm2 , more preferably 10 to 200 μC / cm 2 way of irradiation.

[0672] 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 interposed between the resist film and the projection lens. In this case, a protective film insoluble in water may be used.

[0673] The aforementioned protective film insoluble in water is used to prevent elution from the resist film and improve the water sliding property of the film surface, and can be roughly divided into two types. One of them is an organic solvent stripping type that must be stripped before alkaline aqueous solution development by using an organic solvent that does not dissolve the resist film, and the other is an alkaline aqueous solution soluble type that is soluble in an alkaline developer and removes the protective film at the same time when removing the soluble part of the resist film. The latter is particularly preferably a material based on a polymer having a 1,1,1,3,3,3-hexafluoro-2-propanol residue that is insoluble in water and soluble in an alkaline developer, and that is soluble 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 set to a material in which the aforementioned surfactant that is insoluble in water and soluble in an alkaline developer is dissolved 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.

[0674] After the exposure, PEB may be performed. PEB can be performed, for example, by heating on a hot plate at 60 to 150° C. for 1 to 5 minutes, more preferably 80 to 140° C. for 1 to 3 minutes.

[0675] As for development, for example, a developer containing an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) in an ideal concentration of 0.1 to 5% by mass, more preferably 2 to 3% by mass, is used, and development is performed using general methods such as dipping, puddle, and spraying for an ideal period of 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, whereby the exposed portion is dissolved and a target pattern is formed on the substrate.

[0676] After the resist film is formed, the acid generator and the like from the film surface may be extracted or particles may be washed away by washing with pure water, or water remaining on the film after exposure may be removed.

[0677] Then, the pattern formation can also be performed by a double patterning method. As for the double patterning method, examples include a trench method in which a substrate with a 1:3 trench pattern is processed by the first exposure and etching, and then the position is shifted and a 1:3 trench pattern is formed by the second exposure to form a 1:1 pattern; and a line method in which a first substrate with a 1:3 isolation pattern is processed by the first exposure and etching, and then the position is shifted and a second substrate with a 1:3 isolation pattern formed under the first substrate is processed by the second exposure to form a 1:1 pattern with half the pitch.

[0678] In the pattern forming method of the present invention, a negative tone development method in which an organic solvent is used as a developer to dissolve the unexposed portion instead of the alkaline aqueous solution may be used.

[0679] In the above-mentioned organic solvent development, as the developer, 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, methyl crotonate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, methyl crotonate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl pentano ...propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl pentanoate, methyl crotonate, methyl crotonate, propyl formate, propyl formate, butyl formate, isobutyl formate, amyl formate, is Ethyl beanate, 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.

[0680] Example

[0681] Hereinafter, the present invention will be specifically described by showing synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples. In addition, the following apparatuses were used.

[0682] IR: NICOLET 6700 manufactured by Thermo Fisher Scientific

[0683] · 1 H-NMR: ECA-500 manufactured by JEOL Ltd.

[0684] ·MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0685] [1] Synthesis of onium salts

[0686] [Example 1-1] Synthesis of Onium Salt PAG-1

[0687] [Chemistry 190]

[0688]

[0689] (1) Synthesis of intermediate In-1

[0690] In a nitrogen environment, raw material SM-1 (10.0 g), raw material SM-2 (15.9 g), DMAP (0.5 g) and dichloromethane (100 g) were added to a reaction vessel and cooled with an ice bath. While maintaining the temperature in the reaction vessel below 20°C, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (9.2 g) was directly added in the form of a powder. After addition, the temperature was raised to room temperature and matured for 12 hours. After maturation, water was added to stop the reaction, and the usual aqueous work-up was performed. After the solvent was distilled off, diisopropyl ether was added and the residue was washed to obtain 23.9 g of intermediate In-1 (yield 98%) in the form of an oil.

[0691] (2) Synthesis of PAG-1

[0692] Under nitrogen atmosphere, intermediate In-1 (9.2 g), raw material SM-3 (6.6 g), dichloromethane (50 g), and water (30 g) were added, and after stirring for 15 minutes, the organic layer was separated and sampled, washed with water, and then concentrated under reduced pressure. Methyl isobutyl ketone (50 g) was added to the concentrate and azeotropic dehydration was performed, and then diisopropyl ether was added and the residue was washed, thereby obtaining 11.3 g of the target PAG-1 in the form of an oil (yield 97%).

[0693] The IR spectrum data and TOF-MS results of PAG-1 are shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 1 middle.

[0694] IR(D-ATR):ν=3101,3061,2971,1769,1708,1587,1492,1468,1459,1407,1371,1329,1247,1186,1171 ,1161,1130,1113,1072,1009,992,930,912,887,874,838,763,736,703,642,607,577,553,519,438cm -1 .

[0695] MALDI TOF-MS:POSITIVE M + 317 (equivalent to C 18 H 12 F3S+ )

[0696] NEGATIVE M - 461 (equivalent to C 20 H 14 F5O5 - )

[0697] [Examples 1-2 to 1-9] Synthesis of Onium Salts PAG-2 to PAG-9

[0698] Onium salts PAG-2 to PAG-9 represented by the following formulae were synthesized using corresponding raw materials and known organic synthesis reactions.

[0699] [Chemistry 191]

[0700]

[0701] [Chemistry 192]

[0702]

[0703] [2] Synthesis of base polymer [Synthesis Example] Synthesis of base polymer (P-1 to P-5)

[0704] The monomers were combined and copolymerized in MEK as a solvent, the reaction solution was added to hexane, the precipitated solid was washed with hexane, isolated, and dried to obtain base polymers (P-1 to P-5) with the following compositions. 1 H-NMR, Mw, and Mw / Mn were confirmed by GPC (solvent: THF, standard: polystyrene).

[0705] [Chemistry 193]

[0706]

[0707] [Chemistry 194]

[0708]

[0709] [3] Preparation of chemically amplified resist compositions

[0710] [Examples 2-1 to 2-30, Comparative Examples 1-1 to 1-20]

[0711] The onium salts (PAG-1 to PAG-9) of the present invention, comparative photoacid generators (PAG-A to PAG-E), other photoacid generators (PAG-X, PAG-Y), base polymers (P-1 to P-5) and quenchers (Q-1 to Q-4) having the compositions shown in the following Tables 1 and 2 were dissolved in a solvent containing 0.01 mass % of surfactant A (Omnova) to prepare a solution, and the solution was filtered through a 0.2 μm Teflon (registered trademark) type filter material to prepare chemically amplified resist compositions (R-1 to R-30 and CR-1 to CR-20).

[0712] [Table 1]

[0713]

[0714]

[0715] [Table 2]

[0716]

[0717] In Tables 1 and 2, the solvent, other photoacid generators PAG-X, PAG-Y, comparative photoacid generators PAG-A to PAG-E, quenchers Q-1 to Q-4, and surfactant A are as follows.

[0718] Solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0719] DAA (Diacetone Alcohol)

[0720] Other photoacid generators: PAG-X, PAG-Y

[0721] [Chemistry 195]

[0722]

[0723] ·Comparative photoacid generators: PAG-A to PAG-E

[0724] [Chemistry 196]

[0725]

[0726] Quencher: Q-1~Q-4

[0727] [Chemistry 197]

[0728]

[0729] Surfactant A: 3-methyl-3-(2,2,2-trifluoroethoxymethyl)oxetane·tetrahydrofuran·2,2-dimethyl-1,3-propanediol copolymer (manufactured by Omnova)

[0730] [Chemistry 198]

[0731]

[0732] a:(b+b'):(c+c')=1:4~7:0.01~1 (molar ratio)

[0733] Mw=1500

[0734] [4]EUV lithography evaluation (1)

[0735] [Examples 3-1 to 3-30, Comparative Examples 2-1 to 2-20]

[0736] Each chemically amplified resist composition (R-1 to R-30, CR-1 to CR-20) shown in Tables 1 to 3 was spin-coated on a Si substrate on which a silicon-containing spin-coating hard mask SHB-A940 (containing 43% by mass of silicon) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and pre-baked using a hot plate at 100° C. for 60 seconds to prepare a resist film with a film thickness of 50 nm. The resist film was exposed by an EUV scanning exposure machine NXE3400 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, dipole illumination) while changing the exposure amount and focus (exposure amount pitch: 1 mJ / cm 2 , focal pitch: 0.020 μm) while exposing 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 4 and 5. Thereafter, immersion development was performed for 30 seconds with a 2.38 mass % TMAH aqueous solution, and then rinsed with a rinse material containing a surfactant, and then spin-dried to obtain a positive pattern.

[0737] The obtained LS pattern was observed with CD-SEM (CG6300) manufactured by Hitachi Advanced Technology Co., Ltd., 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.

[0738] [Sensitivity evaluation]

[0739] The optimum exposure 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 define it as the sensitivity. The smaller the value, the higher the sensitivity.

[0740] [EL evaluation]

[0741] From the exposure amount formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm interval width in the above LS pattern, EL (unit: %) was calculated by the following formula. The larger the value, the better the performance.

[0742] EL(%)=(|E1-E2| / Eop)×100

[0743] E1: Optimal exposure for LS pattern with line width of 16.2nm and pitch of 36nm

[0744] E2: Optimal exposure for LS pattern with line width of 19.8nm and pitch of 36nm

[0745] Eop: Optimal exposure for LS pattern with line width of 18nm and pitch of 36nm

[0746] [LWR evaluation]

[0747] For the LS pattern obtained by irradiation with Eop, the dimensions of 10 points in the long side direction of the line are measured, and the value (3σ) tripled by the standard deviation (σ) is calculated as LWR. The smaller this value is, the smaller the roughness is, and the more uniform the line width pattern can be obtained.

[0748] [DOF evaluation]

[0749] As the focal depth evaluation, 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 was obtained. The larger the value, the wider the focal depth.

[0750] [Evaluation of the collapse limit of line patterns]

[0751] The line size of each exposure amount in the optimal focus of the LS pattern was measured at 10 locations in the long-side direction. The thinnest line size that can be obtained without collapse is taken as the collapse limit size. The smaller the value, the better the collapse limit.

[0752] [Table 3]

[0753]

[0754]

[0755] [Table 4]

[0756]

[0757] From the results shown in Tables 3 and 4, it can be understood that the chemically amplified resist composition containing the photoacid generator composed of the onium salt of the present invention has good sensitivity and is excellent in EL, LWR and DOF. In addition, the value of the collapse limit is small, confirming that the resistance to pattern collapse is strong even in fine pattern formation. Based on this, it is shown that the chemically amplified resist composition of the present invention is ideal as a material for EUV lithography.

[0758] [5]EUV lithography evaluation (2)

[0759] [Examples 4-1 to 4-30, Comparative Examples 3-1 to 3-20]

[0760] Each chemically amplified resist composition (R-1 to R-30, CR-1 to CR-20) shown in Tables 1 to 3 was spin-coated on a Si substrate on which a silicon-containing spin-coated hard mask SHB-A940 (containing 43% by mass of silicon) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and pre-baked using a hot plate at 105° C. for 60 seconds to prepare a resist film with a film thickness of 50 nm. The resist film was exposed using an EUV scanner NXE3400 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask of a hole pattern with a size pitch of 46 nm on the wafer and a deviation of +20%), and PEB was performed for 60 seconds using a hot plate at the temperature described in Tables 7 and 8, and developed for 30 seconds using a 2.38% by mass TMAH aqueous solution to form a hole pattern with a size of 23 nm.

[0761] The exposure amount when a hole size of 23 nm was formed was measured using CD-SEM (CG6300) manufactured by Hitachi Advanced Technology Co., Ltd., and the result was used as the sensitivity. The size of 50 holes at this time was measured, and the value (3σ) three times the standard deviation (σ) calculated from the result was defined as the size deviation (CDU). The results are shown in Tables 5 and 6.

[0762] [Table 5]

[0763]

[0764]

[0765] [Table 6]

[0766]

[0767] From the results shown in Tables 5 and 6, it was confirmed that the chemically amplified resist composition containing the photoacid generator composed of the onium salt of the present invention had good sensitivity and excellent CDU.

Claims

1. An onium salt represented by the following formula (1); In the formula, R 1 ~R 12 Each is independently a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; R 13 and R 14 One of them is a group having a partial structure represented by the following formula (1a), and the other is a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; Again, R 1 ~R 14 At least two of them may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, or may be bonded to the carbon atoms to which they are bonded and the carbon atoms between them to form a ring; Z + is an onium cation; Where, L A and L B are each 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 a hetero atom; Q 1 ~Q 3 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; but when Q 1 and Q 2 When all are hydrogen atoms, Q 3 is a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; and, Q 1 ~Q 3 The total number of fluorine atoms in is 2 or more.

2. The onium salt according to claim 1, which is represented by the following formula (1A); In the formula, R 1 ~R 13 , L A , X L , Q 1 ~Q 3 , and Z + Same as above.

3. The onium salt according to claim 2, which is represented by the following formula (1B); In the formula, R 5 , R 10 ~R 13 , L A , X L , Q 1 ~Q 3 and Z + Same as above; n1 and n2 are each independently an integer from 0 to 4; R 15 and R 16 Each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a hetero atom; and when n1 and n2 are 2 or more, a plurality of R 15 and R 16 They may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, or may be bonded to the carbon atoms to which they are bonded and the carbon atoms between them to form a ring.

4. The onium salt according to claim 3, which is represented by the following formula (1C); In the formula, R 5 , R 10 ~R 13 , R 15 , R 16 , L A , X L 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 each 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 to form a ring together with the sulfur atom to which they are bonded. 6 . A photoacid generator, comprising the onium salt according to claim 1 . 7 . A chemically amplified resist composition comprising the photoacid generator according to claim 6 .

8. The chemically amplified resist composition according to claim 7, comprising a base polymer containing 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 -, the phenylene 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. The saturated alkylene group may also 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; AL 1 It is an acid-labile group.

9. The chemically amplified resist composition according to claim 8, wherein: The base polymer comprises 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 to 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 hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl 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.

10. The chemically amplified resist composition according to claim 8, wherein: The base polymer comprises 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 to a carbon atom of the main chain; R 21 A group having 1 to 20 carbon atoms and 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)-); 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 hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl 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; but 1≤b+c≤5.

11. The chemically amplified resist composition according to claim 8, wherein: The base polymer comprises 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 Each is independently a single bond, phenylene, naphthylene or *-C(=O)-OZ 31 -;Z 31 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 Each is independently a single bond, **-Z 41 -C(=O)-O-, **-C(=O)-NH-Z 41 -or**-OZ 41 -;Z 41 is an alkylene group having 1 to 20 carbon atoms which may contain heteroatoms; Z 5 Each is independently a single bond, *-Z 51 -C(=O)-O-, *-C(=O)-NH-Z 51 -or*-OZ 51 -;Z 51 is an alkylene group having 1 to 20 carbon atoms which may 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 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 to a carbon atom in the main chain; ** indicates an atomic bond to Z 3 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 With R 32 They may also bond to each other and form a ring together with the sulfur atom to which they are bonded; 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 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; R 3 and Rf 4 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; R 5 and Rf 6 Each independently represents 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 Not all hydrogen atoms 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.

12. The chemically amplified resist composition according to claim 7, further comprising an organic solvent.

13. The chemically amplified resist composition according to claim 7, further comprising a quencher. 14 . The chemically amplified resist composition according to claim 7 , further comprising a photoacid generator other than the photoacid generator according to claim 6 .

15. The chemically amplified resist composition according to claim 7, further comprising a surfactant.

16. A method for forming a pattern, comprising the following steps: A resist film is formed on a substrate using the chemically amplified resist composition according to claim 7; the resist film is exposed to high-energy rays; and the exposed resist film is developed using a developer.

17. The pattern forming method according to claim 16, 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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