Monomer, polymer, chemically amplified resist composition and pattern forming method

Abstract

The invention relates to a monomer, a polymer, a chemically amplified resist composition and a pattern forming method. Provided is a monomer that is used in a chemically amplified resist composition that has excellent solvent solubility in optical lithography using high-energy rays, high sensitivity / contrast, excellent lithography performance such as exposure margin (EL) and LWR, and excellent pattern shape and etching resistance after development. Also provided are a polymer obtained using the monomer, a chemically amplified resist composition, and a pattern forming method using the chemically amplified resist composition. A monomer represented by formula (A), a polymer containing a repeating unit derived from the monomer, and a chemically amplified resist composition containing a base polymer containing the polymer. # imgabs0 #

Description

Technical Field

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

[0002] With the high integration and high speed of LSI, the miniaturization of pattern rules is progressing rapidly. As 5G high-speed communication and artificial intelligence (AI) become more and more popular, high-performance devices are needed to process them. As the most advanced miniaturization technology, mass production of 5nm node devices using extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm has been carried out. In addition, the next generation 3nm node and the next generation 2nm node devices are being studied using EUV lithography.

[0003] As the miniaturization progresses, the blurring of the image due to acid diffusion becomes a problem. In order to ensure the resolution of fine patterns with a processing size of less than 45nm, it has been proposed that it is not only important to improve the dissolution contrast as previously proposed, but also to control the acid diffusion (Non-Patent Document 1). However, the chemically amplified resist composition improves the sensitivity and contrast by acid diffusion. Therefore, if the post-exposure baking (PEB) temperature is lowered or the time is shortened to suppress the acid diffusion to the limit, the sensitivity and contrast will be significantly reduced.

[0004] Sensitivity, resolution and edge roughness (LER, LWR) show a trade-off relationship. In order to improve the resolution, the acid diffusion must be suppressed, but if the acid diffusion distance is shortened, the sensitivity decreases.

[0005] It is effective to add an acid generator that generates a sterically hindered acid to inhibit acid diffusion. Some people have proposed a scheme to make the polymer contain repeating units from an onium salt having a polymerizable unsaturated bond. In this case, the polymer also acts as an acid generator (polymer-bonded acid generator). Patent document 1 proposes a scheme of sulfonium salts and iodonium salts having a polymerizable unsaturated bond that generate specific sulfonic acids. Patent document 2 proposes a scheme of sulfonium salts in which sulfonic acid is directly bonded to the main chain.

[0006] As miniaturization progresses, pattern collapse during fine pattern formation and resistance to etching steps are particularly important in positive resist compositions. Patent documents 3 and 4 describe polymers that use vinylnaphthalene having a rigid structure as a polymerizable group and contain structural units that partially have polar groups such as lactone structures, acidic groups such as hexafluoroisopropanol structures and carboxyl groups, acetal structures, acid-labile groups such as tertiary ether structures, and the like. In addition, Japanese Patent Document 5 proposes a scheme for an organic solvent-developable negative resist composition that uses a polymer containing vinylnaphthalene units having a chain tertiary ester structure as a constituent unit.

[0007] These resist compositions have improved their performance to some extent, but have not yet achieved satisfactory results. In order to meet the demand for further miniaturization, it is sought to develop acid-labile monomers that have good acid release reactivity to acids and excellent resistance to pattern collapse and etching steps after fine pattern formation.

[0008] Prior art literature

[0009] Patent Literature

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2006-045311

[0011] [Patent Document 2] Japanese Patent Application Publication No. 2006-178317

[0012] [Patent Document 3] International Publication No. 2022 / 186059

[0013] [Patent Document 4] International Publication No. 2023 / 054126

[0014] [Patent Document 5] Japanese Patent No. 5793389 Summary of the invention

[0015] [Problems to be solved by the invention]

[0016] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a monomer used in a chemically amplified resist composition, which has excellent solvent solubility, high sensitivity / high contrast, exposure margin (EL), LWR and other lithography performances, pattern shape, and etching resistance after development, particularly in optical lithography using high-energy rays such as KrF excimer laser, ArF excimer laser, electron beam (EB), and EUV, a polymer obtained using the monomer, a chemically amplified resist composition, and a pattern forming method using the chemically amplified resist composition.

[0017] [Methods for solving problems]

[0018] The inventors of the present application have made great efforts to study in order to achieve the above-mentioned purpose, and as a result, they have found that a monomer having a vinylnaphthalene skeleton as a polymerizable group and having a tertiary ester type acid-labile group bonded thereto, and a polymer containing repeating units derived from the monomer have excellent solvent solubility. The chemically amplified resist composition using the above-mentioned polymer as a base polymer has high sensitivity and high contrast, excellent EL, LWR and other lithography properties, and is extremely effective in suppressing pattern collapse during fine pattern formation and etching resistance after development, thereby completing the present invention.

[0019] That is, the present invention provides the following monomers, polymers, chemically amplified resist compositions and pattern forming methods.

[0020] 1. A monomer represented by the following formula (A),

[0021] [Chemistry 1]

[0022]

[0023] In the formula, a1 is 1 or 2. a2 is an integer of 0-4.

[0024] R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0025] R 1 is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 1 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring.

[0026] L A It is a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond or a carbamate bond.

[0027] X L It is a single bond or a alkylene group having 1 to 40 carbon atoms which may contain a hetero atom.

[0028] R L1 , R L2 and R L3 Each independently represents a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom, R L1 , R L2 and R L3 Any two of them may be bonded to each other and form a ring together with the carbon atoms to which they are bonded. When the aforementioned ring is not formed, R L1 , R L2 and R L3 At least one of the above has at least one structure selected from the group consisting of a multiple bond, an alicyclic ring, and an aromatic ring.

[0029] 2. The monomer as in 1. is represented by the following formula (A1),

[0030] [Chemistry 2]

[0031]

[0032] In the formula, a2, R A , R 1 , L A , X L and R L1 ~R L3 Same as above.

[0033] 3. The monomer as in 2. is represented by the following formula (A2),

[0034] [Chemistry 3]

[0035]

[0036] In the formula, a2, R A , R 1 and R L1 ~R L3 Same as above.

[0037] 4. A polymer comprising repeating units derived from the monomers according to any one of 1. to 3.

[0038] 5. The polymer according to 4. further comprises at least one selected from the group consisting of a repeating unit represented by the following formula (a1) and a repeating unit represented by the following formula (a2),

[0039] [Chemistry 4]

[0040]

[0041] In the formula, R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0042] X 1 is a single bond, phenylene, naphthylene, *-C(=O)-OX 11 - or *-C(=O)-NH-X 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.

[0043] X 2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-.

[0044] *Indicates atomic bonds to carbon atoms in the main chain.

[0045] R 11 It is a halogen atom, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain heteroatoms, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain heteroatoms, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain heteroatoms.

[0046] AL 1 and AL 2 Each is independently an acid-labile group.

[0047] a3 is an integer from 0 to 4.

[0048] 6. The polymer according to 4. or 5., further comprising at least one selected from the group consisting of a repeating unit represented by the following formula (b1) and a repeating unit represented by the following formula (b2),

[0049] [Chemistry 5]

[0050]

[0051] In the formula, R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0052] Y 1 It is a single bond or *-C(=O)-O-. * represents an atomic bond with a carbon atom of the main chain.

[0053] R 21 It is a group having 1 to 20 carbon atoms, or a structure containing at least one selected from the group consisting of a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-).

[0054] R 22 It is a halogen atom, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain heteroatoms, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain heteroatoms, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain heteroatoms.

[0055] b1 is an integer from 1 to 4. b2 is an integer from 0 to 4. However, 1≤b1+b2≤5.

[0056] 7. The polymer according to any one of 4. to 6., further comprising 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),

[0057] [Chemistry 6]

[0058]

[0059] In the formula, R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0060] Z 1 It is a single bond or a phenylene group.

[0061] Z 2 **-C(=O)-OZ 21 -, **-C(=O)-NH-Z 21 -or**-OZ21 -.Z 21 The divalent group is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a combination thereof, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group.

[0062] Z 3 Each is independently a single bond, phenylene, naphthylene or *-C(=O)-OZ 31 -.Z 31 It is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group. The aliphatic alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring.

[0063] Z 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 hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom.

[0064] Z 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 hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom.

[0065] Z 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 61 -, *-C(=O)-N(H)-Z 61 -or*-OZ 61 -.Z 61 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group.

[0066] * indicates the atomic bond between the carbon atoms of the main chain. ** indicates the bond between Z 1 Atomic bonds. *** indicates that Z 3 The atomic bond of Z 4 of atomic bonds.

[0067] R 31 and R 32 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 31 and R 32They may also bond to each other and to the sulfur atom to which they are bonded to form a ring.

[0068] 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.

[0069] R 1 and Rf 2 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0070] 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.

[0071] 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. 5 and Rf 6 At the same time it becomes a hydrogen atom.

[0072] M - It is a non-nucleophilic relative ion.

[0073] A + It is an onium cation.

[0074] c1 and c2 are each independently an integer of 0-3.

[0075] 8. A resist composition comprising a base polymer containing the polymer according to any one of 4. to 7., and an organic solvent.

[0076] 9. The chemically amplified resist composition of 8. further comprises a quencher.

[0077] 10. The chemically amplified resist composition of 8. or 9. further comprises a photoacid generator.

[0078] 11. The chemically amplified resist composition according to any one of 8. to 10., further comprising a surfactant.

[0079] 12. A pattern forming method comprising the following steps:

[0080] Using the chemically amplified resist composition as described in any one of 8. to 11., forming a resist film on a substrate,

[0081] exposing the resist film to high energy radiation, and

[0082] The exposed resist film is developed using a developer.

[0083] 13. The pattern forming method according to 12., 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.

[0084] [Effects of the Invention]

[0085] When a chemically amplified resist composition containing a polymer obtained using the monomer of the present invention as a base polymer is used for pattern formation, a resist pattern having high contrast and good sensitivity, excellent lithography performance such as DOF ​​and LWR, and suppressed pattern collapse can be formed. DETAILED DESCRIPTION

[0086] [monomer]

[0087] The monomer of the present invention is represented by the following formula (A).

[0088] [Chemistry 7]

[0089]

[0090] In formula (A), a1 is an integer of 1 or 2, and from the viewpoint of raw material scheduling, 1 is preferred. a2 is an integer of 0 to 4, and 0, 1 or 2 is preferred, and 0 or 1 is more preferred.

[0091] In formula (A), R A Each independently represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0092] In formula (A), R 1 It is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. 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, dodecanyl, tridecanyl, tetradecanyl, pentadecyl, heptadecyl, octadecyl, nonadecanyl, and eicosyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them. Among these, aryl groups are preferred. Furthermore, some or all of the hydrogen atoms in 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.2 - may be substituted by a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, 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, or the like.

[0093] When a2≥2, multiple R 1 They may also be bonded to each other and form a ring together with the carbon atoms to which they are bonded. Examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. In addition, part or all of the hydrogen atoms in the aforementioned ring 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. The -CH 2 - may be substituted by a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, 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, a haloalkyl group, or the like.

[0094] In formula (A), L A It is a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond or a urethane bond. Among these, a single bond, an ether bond or an ester bond is preferred.

[0095] In formula (A), X L It is a single bond or a carbonylene group having 1 to 40 carbon atoms which may contain a hetero atom. The aforementioned hydrocarbylene group may be linear, branched or cyclic, and specific examples thereof include alkanediyl, cyclic saturated hydrocarbylene, and arylene. Specific examples of the aforementioned heteroatom include oxygen atom, nitrogen atom, and sulfur atom.

[0096] X L Specific examples of the alkylene group having 1 to 40 carbon atoms which may contain a hetero atom represented by are listed below, but are not limited to these. A and the atomic bond of -C(=O)-.

[0097] [Chemistry 8]

[0098]

[0099] [Chemistry 9]

[0100]

[0101] [Chemistry 10]

[0102]

[0103] [Chemistry 11]

[0104]

[0105] Among these, X L -0~X L -22 and X L -47~X L -58 is better.

[0106] In formula (A), R L1 , R L2 and R L3 Each independently represents a hydrocarbon group having 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms, which may contain a hetero atom. L1 , R L2 and R L3 Any two of them may be bonded to each other and form a ring together with the carbon atoms to which they are bonded. When the aforementioned ring is not formed, R L1 , R L2 and R L3 At least one of R has at least one structure selected from a multiple bond, an alicyclic ring, and an aromatic ring. L1 , R L2 and R L3 At least one of the above is preferably a hydrocarbon group having 2 to 30 carbon atoms and containing a multiple bond, a hydrocarbon group having 3 to 30 carbon atoms and containing an alicyclic structure, or a hydrocarbon group having 6 to 30 carbon atoms and containing an aromatic ring structure. 2 - may also be substituted by -O- or -S-.

[0107] In formula (A), -C(R L1 )(R L2 )(R L3 ) may be exemplified by the following, but are not limited thereto. In the following formula, * represents an atomic bond with an adjacent oxygen atom.

[0108] [Chemistry 12]

[0109]

[0110] [Chemistry 13]

[0111]

[0112] [Chemistry 14]

[0113]

[0114] [Chemistry 15]

[0115]

[0116] [Chemistry 16]

[0117]

[0118] [Chemistry 17]

[0119]

[0120] [Chemistry 18]

[0121]

[0122] [Chemistry 19]

[0123]

[0124] [Chemistry 20]

[0125]

[0126] [Chemistry 21]

[0127]

[0128] [Chemistry 22]

[0129] The monomer represented by the formula (A) is preferably represented by the following formula (A1).

[0130] [Chemistry 23]

[0131]

[0132] In the formula, a2, R A , R 1 , L A , X L and R L1 ~R L3 The same as above. The monomer represented by formula (A1) is preferably represented by the following formula (A2).

[0133] [Chemistry 24]

[0134]

[0135] In the formula, a2, R A , R 1 and R L1 ~R L3 Same as above.

[0136] Specific examples of the monomer represented by formula (A) include the following, but are not limited to these.

[0137] [Chemistry 25]

[0138]

[0139] [Chemistry 26]

[0140]

[0141] [Chemistry 27]

[0142]

[0143] [Chemistry 28]

[0144]

[0145] [Chemistry 29]

[0146]

[0147] [Chemistry 30]

[0148]

[0149] [Chemistry 31]

[0150]

[0151] [Chemistry 32]

[0152]

[0153] [Chemistry 33]

[0154]

[0155] [Chemistry 34]

[0156]

[0157] [Chemistry 35]

[0158]

[0159] [Chemistry 36]

[0160]

[0161] [Chemistry 37]

[0162]

[0163] [Chemistry 38]

[0164]

[0165] [Chemistry 39]

[0166]

[0167] [Chemistry 40]

[0168]

[0169] [Chemistry 41]

[0170]

[0171] [Chemistry 42]

[0172]

[0173] [Chemistry 43]

[0174]

[0175] [Chemistry 44]

[0176]

[0177] [Chemistry 45]

[0178]

[0179] [Chemistry 46]

[0180]

[0181] [Chemistry 47]

[0182]

[0183] [Chemistry 48]

[0184]

[0185] [Chemistry 49]

[0186]

[0187] [Chemistry 50]

[0188]

[0189] [Chemistry 51]

[0190]

[0191] [Chemistry 52]

[0192]

[0193] [Chemistry 53]

[0194]

[0195] [Chemistry 54]

[0196]

[0197] [Chemistry 55]

[0198]

[0199] [Chemistry 56]

[0200]

[0201] [Chemistry 57]

[0202]

[0203] [Chemistry 58]

[0204]

[0205] [Chemistry 59]

[0206]

[0207] [Chemistry 60]

[0208]

[0209] [Chemistry 61]

[0210]

[0211] [Chemistry 62]

[0212]

[0213] [Chemistry 63]

[0214]

[0215] [Chemistry 64]

[0216]

[0217] The monomers of the present invention can be synthesized by known methods, such as the method shown in the following scheme.

[0218] [Chemistry 65]

[0219]

[0220] In the formula, a1, a2, R A , R 1 , L A , X L , R L1 ~R L3 Same as above.

[0221] The first reaction is a step of converting the carboxylic acid raw material (SM-1) into the corresponding carboxylic acid chloride to obtain (Pre-A).

[0222] The raw material (SM-1) can be synthesized according to a known method or obtained as a commercial product. The raw material (SM-1) is suspended in an aromatic hydrocarbon solvent such as toluene, a halogen-containing solvent such as dichloromethane, and oxalyl chloride or thionyl chloride is added dropwise to prepare a carboxylic acid chloride. During the preparation, if a small amount of N,N-dimethylformamide is added, the reaction can be accelerated. In order to prepare the carboxylic acid chloride with good efficiency, it is better to heat the temperature of the solvent from room temperature to about the boiling point of the solvent. The reaction time is ideal in terms of yield if the reaction is tracked by gas chromatography (GC) and silica gel thin layer chromatography (TLC) to complete the reaction, but it is usually about 2 to 4 hours. By concentrating the reaction solution, a carboxylic acid chloride (Pre-A) which is a precursor of the target product can be obtained. If necessary, it can be refined according to conventional methods such as distillation, chromatography, and recrystallization.

[0223] The second reaction is a reaction in which a carboxylic acid chloride (Pre-A) which is a precursor of the target product is subjected to an esterification reaction using a tertiary alcohol to obtain a monomer (A) which is the target product.

[0224] The esterification reaction can be carried out according to a known formula. The carboxylic acid chloride (Pre-1) which is the precursor of the target product and the corresponding tertiary alcohol are dissolved in a hydrocarbon solvent such as toluene, hexane, or a polar aprotic solvent such as tetrahydrofuran, acetonitrile, or a halogen-containing solvent such as dichloromethane, 1,2-dichloroethane, and an organic base such as triethylamine and pyridine is added dropwise to react. During the reaction, the reaction can be accelerated by adding 4-dimethylaminopyridine. In order to increase the reaction conversion rate, the reaction can be carried out by heating as needed. The reaction time is preferably about 0.5 to 3 hours in terms of yield if the reaction is completed by tracking the reaction by gas chromatography (GC) or silica gel thin layer chromatography (TLC), but it is usually about 0.5 to 3 hours. The target monomer (A) can be obtained from the reaction mixture by conventional aqueous work-up, and if necessary, it can be purified by conventional methods such as distillation, chromatography, and recrystallization.

[0225] The above-mentioned production method is merely an example, and the production method of the monomer of the present invention is not limited thereto.

[0226] The structural features of the monomer of the present invention include, for example, a rigid vinylnaphthalene as a polymerizable group and a tertiary ester type acid-labile group bonded thereto. The tertiary ester type acid-labile group of the exposed part will cause a deprotection reaction due to the acid generated by the acid generator and generate a carboxyl group. The structure of the tertiary ester is preferably a cyclic structure or a multi-bond structure. In the case of a cyclic structure, the elimination of steric hindrance becomes a driving force to increase the reactivity to acid. In the case of a multi-bond structure, the generation of benzyl cations and allyl cations becomes a driving force to increase the reactivity to acid. Thereby, the contrast between the exposed part and the unexposed part is improved. In the case of a positive resist using an alkaline developer, the exposed part that has undergone a deprotection reaction has an increased affinity for alkaline development, so it can be effectively removed using the developer. The tertiary ester structure composed of a saturated chain alkyl group without a cyclic structure or multi-bonds is not easy to obtain the above-mentioned effect, so the reactivity to acid is not so high. In addition, the vinylnaphthalene structure of the polymerizable group has a rigidity of the aromatic ring of the condensed ring, so the glass transition temperature (Tg) of the polymer is increased. In the unexposed part, it is necessary to have resistance to the alkaline developer. Therefore, the polymer that becomes rigid due to the vinyl naphthalene structure shows resistance to the developer, which will inhibit the peeling of the resist pattern from the substrate and the collapse of the resist pattern, and also shows excellent etching resistance in the subsequent etching step. Due to these multiplying effects, the chemically amplified resist composition containing the polymer obtained by using the monomer of the present invention has a high dissolution contrast, can form a line pattern LWR, a hole pattern CDU, and a pattern that resists pattern collapse and has excellent etching resistance. Therefore, the monomer of the present invention is suitable as a material for a resist composition for fine pattern formation, especially a material for a positive resist composition.

[0227] [polymer]

[0228] The polymer of the present invention is obtained using a monomer represented by formula (A). That is, the polymer of the present invention contains a repeating unit derived from the monomer represented by formula (A) (hereinafter also referred to as repeating unit A). Repeating unit A is represented by the following formula (A').

[0229] [Chemistry 66]

[0230]

[0231] In the formula, a1, a2, R A , R 1 , R L1 ~R L3 , L A and X L Same as above.

[0232] The repeating unit A may be used alone or in combination of two or more.

[0233] The base polymer may further contain a repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1) or a repeating unit represented by the following formula (a2) (hereinafter also referred to as repeating unit a2).

[0234] [Chemistry 67]

[0235]

[0236] In formula (a1) and (a2), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 is a single bond, phenylene, naphthylene, *-C(=O)-OX 11 - or *-C(=O)-NH-X 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 X is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. 2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond with a carbon atom of the main chain. 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. a3 is an integer of 0 to 4.

[0237] In formula (a1) and (a2), AL 1 and AL 2 Each is independently an acid-labile group. The acid-labile group is described in, for example, Japanese Patent Application Laid-Open Nos. 2013-80033 and 2013-83821.

[0238] In general, the acid-labile group is represented by, for example, the following formulae (AL-1) to (AL-3).

[0239] [Chemistry 68]

[0240]

[0241] In the formula, the chain lines are atomic bonds.

[0242] In formula (AL-1) and (AL-2), R L11 and R L12Each 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 linear, branched, or cyclic. The hydrocarbon group preferably has 1 to 20 carbon atoms.

[0243] In formula (AL-1), k is an integer of 0 to 10, preferably an integer of 1 to 5.

[0244] In formula (AL-2), R L13 and R L14 Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. L12 , R L13 and R L14 Any two of them may be bonded to each other and together with the carbon atom or the carbon atom and oxygen atom to which they are bonded form a ring having 3 to 20 carbon atoms. The aforementioned ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0245] In formula (AL-3), R L15 , R L16 and R L17 Each independently represents a hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. L15 , R L16 and R L17 Any two of the above may be bonded to each other and together with the carbon atoms to which they are bonded form a ring having 3 to 20 carbon atoms. The above ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0246] Specific examples of the repeating unit a1 include the following, but are not limited to these. A and AL 1 Same as above.

[0247] [Chemistry 69]

[0248]

[0249] [Chemistry 70]

[0250]

[0251] [Chemistry 71]

[0252]

[0253] Specific examples of the repeating unit a2 include the following, but are not limited to these.A and AL 2 Same as above.

[0254] [Chemistry 72]

[0255]

[0256] [Chemistry 73]

[0257]

[0258] The aforementioned polymer preferably further contains a repeating unit represented by the following formula (b1) (hereinafter also referred to as repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit b2).

[0259] [Chemistry 74]

[0260]

[0261] In formula (b1) and (b2), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 It is a single bond or *-C(=O)-O-. * indicates an atomic bond between the carbon atom of the main chain. 21 It is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one structure selected from the group consisting of a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-). 22 is a halogen atom, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a 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. b1 is an integer of 1 to 4. b2 is an integer of 0 to 4. However, 1≤b1+b2≤5.

[0262] Specific examples of the repeating unit b1 include the following, but are not limited to these. A Same as above.

[0263] [Chemistry 75]

[0264]

[0265] [Chemistry 76]

[0266]

[0267] [Chemistry 77]

[0268]

[0269] [Chemistry 78]

[0270]

[0271] [Chemistry 79]

[0272]

[0273] [Chemistry 80]

[0274]

[0275] [Chemistry 81]

[0276]

[0277] [Chemistry 82]

[0278]

[0279] [Chemistry 83]

[0280]

[0281] [Chemistry 84]

[0282]

[0283] [Chemistry 85]

[0284]

[0285] [Chemistry 86]

[0286]

[0287] [Chemistry 87]

[0288]

[0289] [Chemistry 88]

[0290]

[0291] [Chemistry 89]

[0292]

[0293] [Chemistry 90]

[0294]

[0295] Specific examples of the repeating unit b2 include the following, but are not limited to these. A Same as above.

[0296] [Chemistry 91]

[0297]

[0298] [Chemistry 92]

[0299]

[0300] [Chemistry 93]

[0301]

[0302] [Chemistry 94]

[0303]

[0304] [Chemistry 95]

[0305]

[0306] As for the repeating unit b1 or b2, in ArF lithography, those having a lactone ring as a polar group are particularly preferred, and in KrF lithography, EB lithography and EUV lithography, those having a phenol moiety are preferred.

[0307] The aforementioned polymer may further contain at least one selected from the group consisting of a repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit c1), a repeating unit represented by the following formula (c2) (hereinafter also referred to as repeating unit c2), a repeating unit represented by the following formula (c3) (hereinafter also referred to as repeating unit c3), and a repeating unit represented by the following formula (c4) (hereinafter also referred to as repeating unit c4). These repeating units act as photoacid generators bonded to the main chain of the polymer.

[0308] [Chemistry 96]

[0309]

[0310] 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 31Z 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 Z is a hydrocarbon 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 Z is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 61 -, *-C(=O)-N(H)-Z 61 -or*-OZ 61 -.Z 61 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group. * indicates an atomic bond between the carbon atoms of the main chain. ** indicates an atomic bond between Z 1 Atomic bonds. *** indicates that Z 3 The atomic bond of Z 4 of atomic bonds.

[0311] Z 21 , Z 31 and Z 61 The aliphatic alkylene group represented may be straight-chain, branched or cyclic, and specific examples thereof include 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, hexane-1,6-diyl; cycloalkanediyl such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl and cyclohexanediyl; and groups obtained by combining them.

[0312] Z 41 and Z 51The alkylene group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the following, but are not limited to these.

[0313] [Chemistry 97]

[0314]

[0315] In the formula, the chain line represents the bond hand.

[0316] In formula (c1), R 31 and R 32 Each is independently a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them, among which aryl groups are preferred. Furthermore, some or all of the hydrogen atoms in 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. 2 - may be substituted by a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, 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, or the like.

[0317] Again, R 31 and R 32 They may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. In this case, the aforementioned ring, for example, is the same as that in the following description of formula (cation-1). ct1 and R ct2 The same examples are exemplified as the ring that can be formed together with the sulfur atom to which they are bonded.

[0318] Specific examples of the cation in the repeating unit c1 include the following, but are not limited to these. A Same as above.

[0319] [Chemistry 98]

[0320]

[0321] [Chemistry 99]

[0322]

[0323] [Chemical 100]

[0324]

[0325] [Chemistry 101]

[0326]

[0327] [Chemistry 102]

[0328]

[0329] [Chemistry 103]

[0330]

[0331] [Chemistry 104]

[0332]

[0333] In formula (c1), M - It is a non-nucleophilic relative ion. The aforementioned non-nucleophilic relative ion is preferably a halide ion, a sulfonic acid anion, an imidic acid anion and a methylated acid anion. Specific examples of the aforementioned halide ion include chloride ion, bromide ion, etc. Specific examples of the aforementioned sulfonic acid anion (sulfonate ion) include fluoroalkylsulfonate ions such as trifluoromethanesulfonate ion, 1,1,1-trifluoroethanesulfonate ion, nonafluorobutanesulfonate ion; arylsulfonate ions such as toluenesulfonate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as methanesulfonate ion and butanesulfonate ion, etc. Specific examples of the aforementioned imidic acid anion (imide ion) include bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, bis(perfluorobutylsulfonyl)imide ion, etc. Specific examples of the methylated acid anion (methide ion) include tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0334] Other examples of the non-nucleophilic counter ion include an anion represented by any one of the following formulae (c1-1) to (c1-4).

[0335] [Chemistry 105]

[0336]

[0337] In formula (c1-1), R fais 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 linear, branched, or cyclic. Specific examples thereof include the following R in formula (c1-1-1): fa1 The hydrocarbon groups represented are exemplified by the same examples.

[0338] The anion represented by the formula (c1-1) is preferably represented by the following formula (c1-1-1).

[0339] [Chemistry 106]

[0340]

[0341] In formula (c1-1-1), Q 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, but in order to improve solvent solubility, at least one of them is preferably a trifluoromethyl group. m is an integer of 0 to 4, and 1 is particularly preferred. fa1 It is a hydrocarbon group having 1 to 35 carbon atoms which may contain a hetero atom. The hetero atom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and an oxygen atom is more preferably. The hydrocarbon group preferably has 6 to 30 carbon atoms from the viewpoint of obtaining a high resolution when forming a fine pattern.

[0342] In formula (c1-1-1), R fa1 The hydrocarbon group having 1 to 35 carbon atoms 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, heptadecanyl 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 2-propenyl 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 them.

[0343] Furthermore, some or all of the hydrogen atoms in 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. 2- may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and 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, etc. Examples of hydrocarbon groups containing hetero atoms include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, and 3-oxocyclohexyl.

[0344] 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 preferred, and an ester bond is more preferred.

[0345] Specific examples of anions represented by formula (c1-1) include the following, but are not limited to these. 1 As mentioned above, Ac is acetyl.

[0346] [Chemistry 107]

[0347]

[0348] [Chemistry 108]

[0349]

[0350] [Chemistry 109]

[0351]

[0352] [Chemistry 110]

[0353]

[0354] [Chemistry 111]

[0355]

[0356] [Chemistry 112]

[0357]

[0358] [Chemistry 113]

[0359]

[0360] [Chemistry 114]

[0361]

[0362] [Chemistry 115]

[0363]

[0364] [Chemistry 116]

[0365]

[0366] 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 hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof are as follows: fa1 The hydrocarbon groups represented by are exemplified by the same examples. fb1 and R fb2 Preferably, it is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 They can also bond to each other and to the groups to which they are bonded (-CF 2 -SO 2 -N - -SO 2 -CF 2 -) together to form a ring, in this case, R fb1 and R fb2 The group obtained by bonding to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0367] 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 hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof are as follows: fa1 The hydrocarbon groups represented by are exemplified by the same examples. fc1 , R fc2 and R fc3 Preferably, it is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 They can also bond to each other and to the groups to which they are bonded (-CF 2 -SO 2 -C - -SO 2 -CF 2 -) together to form a ring, in this case, R fc1 and R fc2 The group obtained by bonding to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0368] In formula (c1-4), R fd is a hydrocarbon group having 1 to 40 carbon atoms which may contain heteroatoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof are as follows: fa1 The hydrocarbon groups represented are exemplified by the same examples.

[0369] Specific examples of the anion represented by formula (c1-4) include the following, but are not limited to these.

[0370] [Chemistry 117]

[0371]

[0372] [Chemistry 118]

[0373]

[0374] Examples of the non-nucleophilic counter ion include anions having an aromatic ring substituted with an iodine atom or a bromine atom. Specific examples of such anions are those represented by the following formula (c1-5).

[0375] [Chemistry 119]

[0376]

[0377] 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.

[0378] In formula (c1-5), X BI is an iodine atom or a bromine atom, and when x and / or y is 2 or more, they may be the same as or different from each other.

[0379] In formula (c1-5), L 11 It is a saturated alkylene group having 1 to 6 carbon atoms which may contain a single bond, an ether bond or an ester bond. The saturated alkylene group may be linear, branched or cyclic.

[0380] 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.

[0381] In formula (c1-5), R feis 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 straight-chain, branched, or cyclic. The aforementioned hydrocarbon group, hydrocarbonoxy group, hydrocarbon carbonyl group, hydrocarbon oxycarbonyl group, hydrocarbon carbonyloxy group, and hydrocarbon sulfonyloxy group may be straight-chain, branched, or cyclic. When x and / or z is 2 or more, each R fe They may be the same as or different from each other.

[0382] Among these, R fe 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.

[0383] In formula (c1-5), Rf 11 ~Rf 14 Each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group, and at least one of these is a fluorine atom or a trifluoromethyl group. 11 With Rf 12 They can also be combined to form a carbonyl group. 13 and Rf 14 All of them are preferably fluorine atoms.

[0384] The anions represented by formula (c1-5) include, but are not limited to, the following. BI Same as above.

[0385] [Chemistry 120]

[0386]

[0387] [Chemistry 121]

[0388]

[0389] [Chemistry 122]

[0390]

[0391] [Chemistry 123]

[0392]

[0393] [Chemistry 124]

[0394]

[0395] [Chemistry 125]

[0396]

[0397] [Chemistry 126]

[0398]

[0399] [Chemistry 127]

[0400]

[0401] [Chemistry 128]

[0402]

[0403] [Chemistry 129]

[0404]

[0405] [Chemistry 130]

[0406]

[0407] [Chemistry 131]

[0408]

[0409] [Chemistry 132]

[0410]

[0411] [Chemistry 133]

[0412]

[0413] [Chemistry 134]

[0414]

[0415] [Chemistry 135]

[0416]

[0417] [Chemistry 136]

[0418]

[0419] [Chemistry 137]

[0420]

[0421] [Chemistry 138]

[0422]

[0423] [Chemistry 139]

[0424]

[0425] [Chemistry 140]

[0426]

[0427] [Chemistry 141]

[0428]

[0429] [Chemistry 142]

[0430]

[0431] The aforementioned non-nucleophilic counter ions may also include fluorobenzenesulfonic acid anions bonded to aromatic groups containing iodine atoms as described in Japanese Patent No. 6648726, anions having an acid-decomposable mechanism as described in International Publication No. 2021 / 200056 and Japanese Patent Application Publication No. 2021-70692, anions having a cyclic ether group as described in Japanese Patent Application Publication No. 2018-180525 and Japanese Patent Application Publication No. 2021-35935, and anions as described in Japanese Patent Application Publication No. 2018-92159.

[0432] The non-nucleophilic counter ions may further include anions of benzenesulfonic acid derivatives without steric hindrance of fluorine atoms as described in Japanese Patent Application Publication Nos. 2006-276759, 2015-117200, 2016-65016, and 2019-202974, and benzenesulfonic acid anions without fluorine atoms bonded to an aromatic group containing iodine atoms as described in Japanese Patent No. 6645464, and alkylsulfonic acid anions.

[0433] The non-nucleophilic counter ion may further include anions of disulfonic acids described in JP-A-2015-206932, anions of sulfonic acids on one side and different sulfonamides or sulfonimides on the other side described in WO2020 / 158366, and anions of sulfonic acids on one side and carboxylic acids on the other side described in JP-A-2015-24989.

[0434] 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 these, an ether bond, an ester bond and a carbonyl group are preferred from the viewpoint of synthesis, and an ester bond and a carbonyl group are more preferred.

[0435] 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, fluorine atoms are preferred. 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. Among these, Rf 3 and Rf 4 Preferably, at least one of them is trifluoromethyl.

[0436] 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 At the same time, it becomes a hydrogen atom. Among these, Rf 5 and Rf 6 Preferably, at least one of them is trifluoromethyl.

[0437] In formulae (c2) and (c3), c1 and c2 are each independently an integer of 0 to 3, and 1 is preferred.

[0438] Specific examples of the anion of the repeating unit c2 are listed below, but are not limited to these. A As mentioned above, Me is methyl.

[0439] [Chemistry 143]

[0440]

[0441] [Chemistry 144]

[0442]

[0443] [Chemistry 145]

[0444]

[0445] [Chemistry 146]

[0446]

[0447] [Chemistry 147]

[0448]

[0449] [Chemistry 148]

[0450]

[0451] [Chemistry 149]

[0452]

[0453] [Chemistry 150]

[0454]

[0455] [Chemistry 151]

[0456]

[0457] Specific examples of the anion of the repeating unit c3 are listed below, but are not limited to these. A Same as above.

[0458] [Chemistry 152]

[0459]

[0460] [Chemistry 153]

[0461]

[0462] [Chemistry 154]

[0463]

[0464] [Chemistry 155]

[0465]

[0466] [Chemistry 156]

[0467]

[0468] [Chemistry 157]

[0469]

[0470] [Chemistry 158]

[0471]

[0472] [Chemistry 159]

[0473]

[0474] Specific examples of the anion of the repeating unit c4 are listed below, but are not limited to these. A Same as above.

[0475] [Chemistry 160]

[0476]

[0477] In formulas (c2) to (c4), A + The onium cation is an onium cation. Examples of the onium cation include ammonium cation, sulfonium cation, and iodonium cation, and sulfonium cation and iodonium cation are preferred.

[0478] 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).

[0479] [Chemistry 161]

[0480]

[0481] 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.

[0482] R ct1 ~R ct5 Examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0483] R ct1 ~R ct5The hydrocarbon group represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 30 carbon atoms, such as vinyl, 1-propenyl, 2-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 them, among which aryl groups are preferred. Furthermore, 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. 2 - may be substituted by a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, 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, etc.

[0484] Again, R ct1 and R ct2 They may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. In this case, the structure of the ring may be represented by the following formula.

[0485] [Chemistry 162]

[0486]

[0487] In the formula, the chain line is and R ct3 of atomic bonds.

[0488] Specific examples of the sulfonium cation represented by the formula (cation-1) include the following, but are not limited to these.

[0489] [Chemistry 163]

[0490]

[0491] [Chemistry 164]

[0492]

[0493] [Chemistry 165]

[0494]

[0495] [Chemistry 166]

[0496]

[0497] [Chemistry 167]

[0498]

[0499] [Chemistry 168]

[0500]

[0501] [Chemistry 169]

[0502]

[0503] [Chemistry 170]

[0504]

[0505] [Chemistry 171]

[0506]

[0507] [Chemistry 172]

[0508]

[0509] [Chemistry 173]

[0510]

[0511] [Chemistry 174]

[0512]

[0513] [Chemistry 175]

[0514]

[0515] [Chemistry 176]

[0516]

[0517] [Chemistry 177]

[0518]

[0519] [Chemistry 178]

[0520]

[0521] [Chemistry 179]

[0522]

[0523] [Chemistry 180]

[0524]

[0525] [Chemistry 181]

[0526]

[0527] [Chemistry 182]

[0528]

[0529] [Chemistry 183]

[0530]

[0531] [Chemistry 184]

[0532]

[0533] [Chemistry 185]

[0534]

[0535] [Chemistry 186]

[0536]

[0537] [Chemistry 187]

[0538]

[0539] [Chemistry 188]

[0540]

[0541] [Chemistry 189]

[0542]

[0543] Specific examples of the iodonium cation represented by the formula (cation-2) include the following, but are not limited to these.

[0544] [Chemistry 190]

[0545]

[0546] [Chemistry 191]

[0547]

[0548] The specific structure of the repeating units c1 to c4 is, for example, any combination of the aforementioned anions and cations.

[0549] 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 generated acid, and repeating unit c2 is more preferable from the viewpoint of solvent solubility.

[0550] The aforementioned 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 more hydroxyl groups are protected and the protecting group is decomposed by the action of an acid to generate a hydroxyl group, and the one represented by the following formula (d1) is preferred.

[0551] [Chemistry 192]

[0552]

[0553] 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.

[0554] 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).

[0555] [Chemistry 193]

[0556]

[0557] In the formula, * represents an atomic bond. 43 It is a hydrocarbon group having 1 to 15 carbon atoms.

[0558] 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 are the same as those described and exemplified in the repeating unit d described in Japanese Patent Application Laid-Open No. 2020-111564.

[0559] The base polymer may further contain a repeating unit e derived from indene, benzofuran, benzothiophene, vinylnaphthalene, chromone, coumarin, norbornadiene or a derivative thereof. Specific examples of the monomer providing the repeating unit e include the following, but are not limited thereto.

[0560] [Chemistry 194]

[0561]

[0562] The foregoing base polymer may further contain repeating unit f derived from indene, vinylpyridine or vinylcarbazole.

[0563] In the polymer of the present invention, the content ratios of repeating units A, a1, a2, b1, b2, c1 to c4, d, e and f are preferably 0 < A ≤ 0.8, 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, more preferably 0 < A ≤ 0.5, 0 ≤ a1 ≤ 0.5, 0 ≤ a2 ≤ 0.5, 0 ≤ b1 ≤ 0.5, 0 ≤ b2 ≤ 0.5, 0 ≤ c1 ≤ 0.3, 0 ≤ c2 ≤ 0.3, 0 ≤ c3 ≤ 0.3, 0 ≤ c4 ≤ 0.3, 0 ≤ d ≤ 0.3, 0 ≤ e ≤ 0.3 and 0 ≤ f ≤ 0.3.

[0564] The weight average molecular weight (Mw) of the foregoing polymer is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no concern that the resolution decreases due to the inability to ensure the difference in dissolution rate before and after exposure. In the present invention, Mw is a polystyrene conversion measured value obtained by gel permeation chromatography (GPC) using THF or N,N-dimethylformamide (DMF) as a solvent.

[0565] Furthermore, as the pattern rule is miniaturized, the influence of Mw / Mn on the molecular weight distribution (Mw / Mn) of the foregoing polymer tends to increase. Therefore, in order to obtain a resist composition suitable for use with a fine pattern size, a narrow dispersion with Mw / Mn of 1.0 to 2.0 is preferred. If it is within the above range, there are few low molecular weight and high molecular weight polymers, and after exposure, there is no concern that foreign substances appear on the pattern or the shape of the pattern deteriorates.

[0566] To synthesize the foregoing polymer, for example: monomers providing the foregoing repeating units are placed in an organic solvent, a radical polymerization initiator is added and heated, and polymerization is carried out.

[0567] The organic solvent used in the polymerization is, for example, toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), etc. As for the above-mentioned polymerization initiator, for example, 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, etc. The amount of these initiators added is preferably 0.01 to 25 mol% relative to the total of the monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, and 60 to 100°C is more ideal. The reaction time is preferably 2 to 24 hours, and from the perspective of production efficiency, 2 to 12 hours is more ideal.

[0568] The above-mentioned polymerization initiator can be added to the above-mentioned monomer solution and supplied to the reactor, or the initiator solution can be prepared separately from the above-mentioned monomer solution and supplied to the reactor independently. During the standby time, the polymerization reaction may proceed due to the free radicals generated from the initiator and ultra-high molecular weight bodies may be produced. Considering the viewpoint of quality management, it is better to prepare the monomer solution and the initiator solution independently and add them dropwise. Monomers with acid-labile groups introduced into them can be used directly, and they can be protected or partially protected after polymerization. In addition, in order to adjust the molecular weight, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can also be used. In this case, the addition amount of these chain transfer agents is preferably 0.01 to 20 mol% relative to the total of the monomers to be polymerized.

[0569] In the case of a monomer containing a hydroxyl group, the hydroxyl group may be replaced with an acetal group such as ethoxyethoxy which is easily deprotected by acid during polymerization, and then deprotected by weak acid and water after polymerization. The hydroxyl group may be replaced with an acetyl group, formyl group, pivaloyl group, etc. in advance, and then hydrolyzed with alkali after polymerization.

[0570] 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 mixture is polymerized by heating. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene is used, and after polymerization, the acetoxy group is deprotected by alkaline hydrolysis to form polyhydroxystyrene or hydroxyvinylnaphthalene.

[0571] The base used in the alkaline hydrolysis may be aqueous ammonia, triethylamine, etc. The reaction temperature is preferably -20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0572] The amount of each monomer in the monomer solution may be appropriately set, for example, so as to achieve a desired content ratio of the repeating unit.

[0573] The polymer obtained by the above-mentioned manufacturing method can be used as the final product by using the reaction solution obtained by the polymerization reaction, or can be treated as the final product by using the powder obtained by adding the polymerization solution to a poor solvent and reprecipitation method. Considering the viewpoints of operating efficiency and quality stabilization, it is better to treat the polymer solution obtained by dissolving the powder obtained by the refining step in a solvent as the final product.

[0574] 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, dimethoxypropanol, and the like; Ethers such as ethylene 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, 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.

[0575] 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.

[0576] The reaction solution and polymer solution are preferably filtered. Filtering can remove foreign matter and gel that may cause defects, which is effective in stabilizing quality.

[0577] The material of the filter used for the above-mentioned filter filtration can be listed as fluorocarbon, cellulose, nylon, polyester, hydrocarbon and other materials, but in the filtering step of the resist composition, a filter formed of fluorocarbon, polyethylene, polypropylene and other hydrocarbons or nylon called Teflon (registered trademark) is preferred. The pore size of the filter can be appropriately selected according to the cleanliness of the target, but it is preferably less than 100nm, and more preferably less than 20nm. In addition, these filters can be used alone or in combination. The filtering method can only pass the solution once, but it is better to circulate the solution and filter it multiple times. The filtering step can be performed in any order and number of times in the manufacturing step of the polymer, but it is better to filter the reaction solution, polymer solution or both after the polymerization reaction.

[0578] [Chemically amplified resist composition]

[0579] [(A) Base polymer]

[0580] The chemically amplified resist composition of the present invention contains (A) a base polymer including the above-mentioned polymer.

[0581] In the base polymer of the component (A), the aforementioned polymers 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 (A) may contain a hydrogenated product of a ring-opening metathesis polymer in addition to the aforementioned polymers, and in this regard, the polymer described in Japanese Patent Application Laid-Open No. 2003-66612 may be used.

[0582] [(B) Organic solvent]

[0583] The chemically amplified resist composition of the present invention contains an organic solvent as component (B). The aforementioned organic solvent is not particularly limited as long as it can dissolve the aforementioned components and the components described below. Such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ketone alcohols such as DAA; ethers such as PGME, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as GBL; mixed solvents thereof, etc.

[0584] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixed solvents thereof are preferred, in which the base polymer of the component (A) has particularly excellent solubility.

[0585] In the chemically amplified resist composition of the present invention, the content of the organic solvent (B) is preferably 200 to 5000 parts by mass, more preferably 400 to 3500 parts by mass, based on 80 parts by mass of the base polymer (A). The organic solvent (B) may be used alone or in combination of two or more.

[0586] [(C) Quencher]

[0587] The chemically amplified resist composition of the present invention may also contain a quencher as component (C). In the present invention, the quencher refers to a material that forms a desired pattern by capturing the acid generated by the photoacid generator in the chemically amplified resist composition and preventing the acid from diffusing to the unexposed area.

[0588] (C) Examples of the quencher include onium salts represented by the following formula (C1) or (C2).

[0589] [Chemistry 195]

[0590]

[0591] In formula (C1), R q1 is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom, except that the hydrogen atom bonded to the carbon atom at the α-position of the sulfonic group is substituted by 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.

[0592] R q1 The hydrocarbon group having 1 to 40 carbon atoms represented by the present invention is specifically an alkyl group having 1 to 40 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbon groups having 3 to 40 carbon atoms, such as decyl and adamantyl; aryl groups having 6 to 40 carbon atoms, such as phenyl, naphthyl, anthracenyl, etc. In addition, some 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 the -CH 2 - may also be substituted by a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, 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, etc.

[0593] R q2 Specifically, for example, R q1 In addition to the substituents exemplified as specific examples of , fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl may be mentioned.

[0594] Specific examples of the anion of the onium salt represented by the formula (C1) include the following, but are not limited to these.

[0595] [Chemistry 196]

[0596]

[0597] [Chemistry 197]

[0598]

[0599] [Chemistry 198]

[0600]

[0601] [Chemistry 199]

[0602]

[0603] Specific examples of the anion of the onium salt represented by formula (C2) include the following, but are not limited to these.

[0604] [Chemistry 200]

[0605]

[0606] [Chemistry 201]

[0607]

[0608] [Chemistry 202]

[0609]

[0610] In formula (C1) and (C2), 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).

[0611] [Chemistry 203]

[0612]

[0613] 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 With R ct7 They may also be bonded to each other and to form a ring together with the nitrogen atom to which they are bonded. The aforementioned hydrocarbon group may be exemplified as described in the formula (cation-1) and (cation-2). ct1 ~R ct5 The hydrocarbon groups represented are exemplified by the same examples.

[0614] Specific examples of the ammonium cation represented by the formula (cation-3) include the following, but are not limited to these.

[0615] [Chemistry 204]

[0616]

[0617] Specific examples of the onium salt represented by formula (C1) or (C2) include any combination of the aforementioned anions and cations. In addition, these onium salts can be easily prepared by ion exchange reaction using known organic chemical methods. For ion exchange reaction, for example, reference can be made to Japanese Patent Publication No. 2007-145797.

[0618] The onium salt represented by formula (C1) or (C2) acts as a quencher in the chemically amplified resist composition of the present invention. This is because each of the counter anions of the aforementioned onium salt is a conjugate base of a weak acid. The onium salt represented by formula (C1) or (C2) acts as a quencher when used in combination with an onium salt-type photoacid generator having a conjugate base of a strong acid such as an α-fluorinated sulfonic acid as a counter anion. That is, when an onium salt that generates a strong acid such as an α-fluorinated sulfonic acid is used in combination with an onium salt that generates a weak acid such as an unfluorinated sulfonic acid or carboxylic acid, 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. In this process, the strong acid is exchanged for a weak acid with a lower catalytic ability, so the acid is macroscopically inactivated and acid diffusion can be controlled. In the present invention, a weak acid refers to a compound having an acidity that is too high to deprotect the acid-labile group of the acid-labile group-containing unit used in the base polymer, and a strong acid refers to a compound having an acidity sufficient to cause a deprotection reaction of the acid-labile group.

[0619] In addition, (C) quenching agent may also be an onium salt having a sulfonium cation and a phenoxide anion site in the same molecule as described in Japanese Patent No. 6848776, an onium salt having a sulfonium cation and a carboxyl anion site in the same molecule as described in Japanese Patent No. 6583136 and Japanese Patent Application Laid-Open No. 2020-200311, and an onium salt having an iodonium cation and a carboxyl anion site in the same molecule as described in Japanese Patent No. 6274755.

[0620] Here, when the photoacid generator that generates a strong acid is an onium salt, the strong acid generated by high-energy ray irradiation can be exchanged for a weak acid as described above, but on the other hand, it is considered difficult to exchange salts due to collision between the weak acid generated by high-energy ray irradiation and the unreacted onium salt that generates a strong acid. The reason is that the onium cation is more likely to form an ion pair with the anion of the strong acid.

[0621] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (2) or (3) as the quencher (C), the content thereof is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, relative to 80 parts by mass of the base polymer (A). If the onium salt-type quencher of the component (C) is within the above range, the resolution is good and the sensitivity does not decrease significantly, which is ideal. The onium salt represented by formula (C1) or (C2) can be used alone or in combination of two or more.

[0622] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as (C) a quencher. The nitrogen-containing compound of the component (C) is, for example, a primary, secondary or tertiary amine compound described in paragraphs

[0146] to

[0164] of Japanese Patent Application Laid-Open No. 2008-111103, especially an amine compound having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group or a sulfonate bond. In addition, compounds described in Japanese Patent No. 3790649 and compounds in which a primary or secondary amine is protected by a carbamate group may also be mentioned.

[0623] In addition, the nitrogen-containing compound may also be a sulfonium sulfonate salt having a nitrogen-containing substituent. Such a compound acts as a quencher in the unexposed part, and the exposed part loses the quencher ability due to neutralization with the acid generated by itself, and acts as a so-called photodisintegration base. By using a photodisintegration base, the contrast between the exposed part and the unexposed part can be further enhanced. For example, the photodisintegration base can be referred to Japanese Patent Publication No. 2009-109595, Japanese Patent Publication No. 2012-46501, etc.

[0624] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as (C) a 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 base polymer (A). The nitrogen-containing compound may be used alone or in combination of two or more.

[0625] [(D) Photoacid generator]

[0626] The chemically amplified resist composition of the present invention may contain a photoacid generator as component (D). The photoacid generator is not particularly limited as long as it is a compound that generates a strong acid upon exposure to high-energy radiation.

[0627] A preferred photoacid generator is, for example, one represented by the following formula (D1) or (D2).

[0628] [Chemistry 205]

[0629]

[0630] In formula (D1) and (D2), R 101 ~R 105are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 101 , R 102 and R 103 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. ct1 ~R ct5 The hydrocarbon groups represented are exemplified by the same examples.

[0631] Specific examples of the cation of the sulfonium salt represented by formula (D1) are the same as those exemplified for the sulfonium cation represented by formula (cation-1). Specific examples of the cation of the iodonium salt represented by formula (D2) are the same as those exemplified for the iodonium cation represented by formula (cation-2).

[0632] In formula (D1) and (D2), Xa - The anion of a strong acid is, for example, any one of (c1-1) to (c1-5).

[0633] Furthermore, the photoacid generator of the component (D) is preferably represented by the following formula (D3).

[0634] [Chemistry 206]

[0635]

[0636] In formula (D3), R 201 and R 202 Each R is independently a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. 203 is a alkylene group having 1 to 30 carbon atoms which may contain a hetero atom. 201 , R 202 and R 203 Any two of them may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

[0637] 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, anthracenyl, etc.; groups obtained by combining them, etc. In addition, some 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 the -CH 2 - may also be substituted by a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, 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, etc.

[0638] R 203 The alkylene group having 1 to 30 carbon atoms 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 , 1,17-diyl and other alkanediyl groups having 1 to 30 carbon atoms, such as cyclopentanediyl, cyclohexanediyl, norbornanediyl and adamantanediyl, etc.; 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, etc. In addition, some or all of the hydrogen atoms of the aforementioned alkylene groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms and halogen atoms, and the -CH 2 - may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, 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, etc. The hetero atom is preferably an oxygen atom.

[0639] In formula (D3), L 11 is a single bond, an ether bond, or an alkylene group having 1 to 20 carbon atoms which may contain heteroatoms. The alkylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. 203 The alkylene groups represented by are exemplified by the same examples.

[0640] In formula (D3), 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.

[0641] The photoacid generator represented by formula (D3) is preferably represented by the following formula (D3').

[0642] [Chemistry 207]

[0643]

[0644] In formula (D3'), L 11 Same as above. e R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 Each is independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof are as in formula (c1-1-1): fa1 The hydrocarbon groups represented by are exemplified by the same examples. p and q are each independently an integer of 0-5, and r is an integer of 0-4.

[0645] The photo-acid generator represented by formula (D3) is the same as the photo-acid generator exemplified in formula (2) of JP-A-2017-26980.

[0646] Among the above-mentioned photoacid generators, those containing anions represented by formula (c1-1-1) or (c1-4) are particularly preferred because they have low acid diffusion and excellent solubility in solvents. Also, those represented by formula (D3') are particularly preferred because they have extremely low acid diffusion.

[0647] When the chemically amplified resist composition of the present invention contains a (D) photoacid generator, its content 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 (A) base polymer. If the amount of the photoacid generator of the (D) component added is within the aforementioned range, the resolution is good, and there is no concern about the generation of foreign matter after the resist film is developed or peeled off, so it is ideal. The (D) photoacid generator can be used alone or in combination of two or more. In addition, when the base polymer contains any of the repeating units c1 to c4 (that is, a polymer-bonded photoacid generator), the admixture of the (D) photoacid generator can also be omitted.

[0648] [(E) Surfactant]

[0649] The chemically amplified resist composition of the present invention may also contain a surfactant as the component (E). The surfactant (E) is preferably a surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer, or a surfactant that is insoluble or poorly soluble in water and an alkaline developer. Such surfactants can be described in Japanese Patent Application Publication No. 2010-215608 and Japanese Patent Application Publication No. 2011-16746.

[0650] The surfactant that is insoluble or poorly soluble in water and alkaline developer is preferably one of the surfactants listed in the aforementioned gazette, FC-4430 (manufactured by 3M Company), surflon (registered trademark) S-381 (manufactured by AGC Seimichemical Co., Ltd.), OLFINE (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimichemical Co., Ltd.), and the oxetane ring-opening polymer represented by the following formula (surf-1).

[0651] [Chemistry 208]

[0652]

[0653] Here, R, Rf, A, B, C, m, and n are not limited to the above description and are only applicable to formula (surf-1). R is a 2- to 4-valent aliphatic group having 2 to 5 carbon atoms. The above aliphatic group includes, for example, ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentylene, etc. for 2-valent groups, and for example, the following for 3- or 4-valent groups.

[0654] [Chemistry 209]

[0655]

[0656] In the formula, chain lines are atomic bonds, and each is a partial structure derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0657] Among these, 1,4-butylene group, 2,2-dimethyl-1,3-propylene group and the like are preferred.

[0658] 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 block-bonded or randomly bonded. 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.

[0659] Surfactants that are insoluble or poorly soluble in water and soluble in alkaline developer have the effect of reducing water penetration and leaching by aligning on the surface of the resist film when no resist protective film is used in ArF immersion lithography. Therefore, it is useful to inhibit the dissolution of water-soluble components from the resist film and reduce damage to the exposure device. In addition, it is useful because it can be dissolved during development with an alkaline aqueous solution after exposure or after post-exposure baking (PEB) and is not likely to become foreign matter that causes defects. Such surfactants have the properties of being insoluble or poorly soluble in water and soluble in alkaline developer. They are polymer-type surfactants, also called hydrophobic resins, and those with high water repellency and improved water sliding properties are particularly preferred.

[0660] Specific examples of such polymeric surfactants include, for example, those containing at least one type of repeating unit selected from the group consisting of repeating units represented by any one of the following formulae (E1) to (E5).

[0661] [Chemistry 210]

[0662]

[0663] In formulas (E1) to (E5), R B W is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 -CH 2 -、-CH 2 CH 2 -, -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, an ether bond or a carbonyl group may be inserted between the carbon-carbon bonds. s4is 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 inserted between the carbon-carbon bonds.

[0664] R s1 The 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 preferred.

[0665] R s2 The alkylene group represented by is preferably a saturated alkylene group, and may be any of a linear, branched, or cyclic type, and specific examples thereof include methylene, ethylene, propylene, butylene, and pentylene.

[0666] 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, and saturated hydrocarbon groups are preferred. s1 In addition to the hydrocarbon groups exemplified above, undecyl, dodecanyl, tridecanyl, tetradecyl, pentadecyl and the like can be further mentioned. s3 or R s6 The fluorinated hydrocarbon group represented by is a group in which a part or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon group are replaced by fluorine atoms. As mentioned above, an ether bond or a carbonyl group may be inserted between these carbon-carbon bonds.

[0667] R s3 Specific examples of the acid-labile group include groups represented by the above formulae (AL-1) to (AL-3), trialkylsilyl groups in which each alkyl group is an alkyl group having 1 to 6 carbon atoms, and alkyl groups having an oxo group having 4 to 20 carbon atoms.

[0668] R s4 The (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group represented may be linear, branched or cyclic, and a specific example thereof is a group obtained by removing u hydrogen atoms from the above-mentioned hydrocarbon group or fluorinated hydrocarbon group.

[0669] R saThe fluorinated hydrocarbon group represented is preferably saturated, and may be any of linear, branched, and cyclic. Specific examples thereof include those in which a part or all of the hydrogen atoms of the aforementioned hydrocarbon group are substituted by fluorine atoms, and specific examples thereof include trifluoromethyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoro-1-propyl, 3,3,3-trifluoro-2-propyl, 2,2,3,3-tetrafluoropropyl, 1,1,1,3,3,3-hexafluoroisopropyl, 2,2,3,3,4,4,4-heptafluorobutyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, 2-(perfluorodecyl)ethyl, and the like.

[0670] Specific examples of the repeating unit represented by any one of formulae (E1) to (E5) include the following, but are not limited thereto. B Same as above.

[0671] [Chemistry 211]

[0672]

[0673] [Chemistry 212]

[0674]

[0675] [Chemistry 213]

[0676]

[0677] [Chemistry 214]

[0678]

[0679] [Chemistry 215]

[0680]

[0681] [Chemistry 216]

[0682]

[0683] The aforementioned polymeric surfactant may further contain other repeating units other than the repeating units represented by formulas (E1) to (E5). Other repeating units include, for example, repeating units obtained from methacrylic acid, α-trifluoromethylacrylic acid derivatives, etc. In the polymeric surfactant, the content of the repeating units represented by formulas (E1) to (E5) is preferably 20 mol% or more of all the repeating units, more preferably 60 mol% or more, and even more preferably 100 mol%.

[0684] 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.

[0685] The method for synthesizing the aforementioned polymer surfactant is, for example, a method of adding a free radical initiator to a repeating unit represented by formula (E1) to (E5) and, if necessary, to another repeating unit, to a monomer containing an unsaturated bond, in an organic solvent and polymerizing it by heating. The organic solvent used in the polymerization is, for example, toluene, benzene, THF, diethyl ether, dioxane, etc. The polymerization initiator is, for example, AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylpropionic acid) dimethyl ester, benzoyl peroxide, lauroyl peroxide, etc. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. Monomers into which acid-labile groups have been introduced can be used directly, and protection or partial protection can also be performed after polymerization.

[0686] When synthesizing the aforementioned polymer surfactant, a known chain transfer agent such as dodecyl mercaptan or 2-mercaptoethanol may be used to adjust the molecular weight. In this case, the amount of the chain transfer agent added is preferably 0.01 to 10 mol% relative to the total molar number of the monomers to be polymerized.

[0687] When the chemically amplified resist composition of the present invention contains (E) surfactant, its content is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass relative to 80 parts by mass of the (A) base polymer. If the content of (E) surfactant is 0.1 parts by mass or more, the receding contact angle between the resist film surface and water is sufficiently improved, and if it is 50 parts by mass or less, the dissolution rate of the resist film surface to the developer is low, and the height of the fine pattern formed can be sufficiently ensured. (E) Surfactants can be used alone or in combination of two or more.

[0688] [(F) Other ingredients]

[0689] The chemically amplified resist composition of the present invention may contain, as (F) other components, a compound that generates acid by acid decomposition (acid multiplication compound), an organic acid derivative, a fluorinated alcohol, a compound with a Mw of 3,000 or less that changes its solubility in a developer by the action of an acid (dissolution inhibitor), etc. The acid multiplication compound may refer to the compounds described in Japanese Patent Application Laid-Open No. 2009-269953 or Japanese Patent Application Laid-Open No. 2010-215608. When the acid multiplication compound is contained, the content thereof is preferably 0 to 5 parts by weight, and more preferably 0 to 3 parts by weight, relative to 80 parts by weight of the base polymer (A). If the content is too high, it is difficult to control the diffusion of the acid, which may cause degradation of resolution and degradation of the pattern shape. The organic acid derivative, the fluorinated alcohol, and the dissolution inhibitor may refer to the compounds described in Japanese Patent Application Laid-Open No. 2009-269953 or Japanese Patent Application Laid-Open No. 2010-215608.

[0690] [Pattern Formation Method]

[0691] 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.

[0692] The aforementioned substrate may be, for example, a substrate (Si, SiO 2 , SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflection film, etc.), or substrates for mask circuit manufacturing (Cr, CrO, CrON, MoSi 2 、SiO 2 wait).

[0693] The resist film can be formed by coating the chemically amplified resist composition on a substrate by spin coating or the like, preferably with a film thickness of 0.05 to 2 μm, and pre-baking it on a hot plate, preferably at 60 to 150° C. for 1 to 10 minutes, more preferably at 80 to 140° C. for 1 to 5 minutes.

[0694] The resist film is exposed using high energy radiation such as KrF excimer laser, ArF excimer laser, EB, EUV, etc. When using KrF excimer laser, ArF excimer laser or EUV, the exposure can be performed through a mask for forming a target pattern so that the exposure amount is preferably 1 to 200 mJ / cm 2 , preferably 10 to 100 mJ / cm 2 When EB is used, a mask or direct irradiation is used to form a target pattern, and the exposure amount is preferably 1 to 300 μC / cm 2 , preferably 10 to 200 μC / cm2 .

[0695] In addition to the usual exposure method, an immersion method in which a liquid having a refractive index of 1.0 or more is inserted between the resist film and the projection lens may be used for exposure. In this case, a water-insoluble protective film may also be used.

[0696] The aforementioned water-insoluble protective film is used to prevent elution from the resist film and improve the water sliding property of the film surface, and there are two kinds of them. One kind is an organic solvent-removable type that must be peeled off before alkaline aqueous solution development using an organic solvent that does not dissolve the resist film, and the other kind is an alkaline aqueous solution-soluble type that is soluble in an alkaline developer and removes the protective film along with the removal of the soluble part of the resist film. The latter is particularly preferably based on a polymer having a 1,1,1,3,3,3-hexafluoro-2-propanol residue that is insoluble in water and soluble in an alkaline developer and 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, or a mixed solvent thereof. It is also possible to make the aforementioned water-insoluble and alkaline developer-soluble surfactant soluble 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.

[0697] After the exposure, PEB may be performed. PEB may be performed, for example, by heating on a hot plate, preferably at 60 to 150° C. for 1 to 5 minutes, more preferably at 80 to 140° C. for 1 to 3 minutes.

[0698] Development, for example: using a developer such as an alkaline aqueous solution of tetramethylammonium hydroxide (TMAH) preferably in an amount of 0.1 to 5% by mass, more preferably 2 to 3% by mass, preferably for 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, by a conventional method such as dipping, puddle, or spraying, whereby the exposed portion is dissolved to form a desired pattern on the substrate.

[0699] After the resist film is formed, pure water rinsing may be performed to extract an acid generator from the film surface or to wash away particles. Rinsing may also be performed to remove water remaining on the film after exposure.

[0700] Furthermore, a double patterning method can also be used for pattern formation. The double patterning method includes, for example, a trench method in which a substrate with a 1:3 trench pattern is processed by a first exposure and etching, and a 1:3 trench pattern is formed by shifting the position and using a second exposure to form a 1:1 pattern; and a line method in which a first substrate with a 1:3 isolated residual pattern is processed by a first exposure and etching, and a second substrate with a 1:3 isolated residual pattern formed under the first substrate is processed by shifting the position and using a second exposure to form a 1:1 pattern with half the pitch is formed.

[0701] In the pattern forming method of the present invention, a negative tone development method in which an organic solvent is used as a developer instead of the alkaline aqueous solution to dissolve the unexposed portion may be used.

[0702] In the above-mentioned organic solvent development, the developer can use 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, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, crotonyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl croton ...propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl crotonate, methyl crotonate, methyl crotonate, methyl crotonate, methyl crotonate, methyl crotonate, methyl crotonate, methyl crotonate, methyl crotonate, methyl crotonate, methyl crotonate, methyl crotonate, methyl crotonate ethyl acetate, 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.

[0703] Example

[0704] The following synthesis examples, embodiments and comparative examples are given to specifically illustrate the present invention, but the present invention is not limited to the following embodiments. In addition, the structure of the compound is confirmed by measuring the molecular ion peak using mass spectrometry (LC is Agilent 1100 type, MASS is Agilent LC / MSD type). The value of this molecular ion peak is represented by "MASS".

[0705] [1]Synthesis of monomers

[0706] [Example 1-1] Synthesis of Monomer A1

[0707] [Chemistry 217]

[0708]

[0709] Under nitrogen atmosphere, ethylene naphthalene carboxylic acid (19.6 g) was suspended in toluene (80 g). Oxalyl chloride (15.2 g) was added dropwise. After the addition, the internal temperature was raised to 40°C and ripened for 4 hours. After ripening, the reaction solution was concentrated to obtain acid chloride (19.7 g). Then, 1-methylcyclopentanol (12.0 g), 4-dimethylaminopyridine (1.2 g), and THF (80 g) were added and cooled in an ice bath. After cooling, a solution consisting of triethylamine (13.2 g) and THF (20 g) was added dropwise while maintaining the internal temperature below 20°C. After the addition, the internal temperature was raised to 50°C and ripened for 12 hours. After ripening, the reaction solution was cooled in an ice bath and the reaction was stopped with saturated sodium bicarbonate water (50 g). The target product was extracted with a solvent consisting of toluene (100 ml) and ethyl acetate (50 ml), and a conventional aqueous work-up was performed. After the solvent was distilled off, the product was purified by silica gel chromatography to obtain 21.2 g of monomer A1 as a colorless oil (yield 76%).

[0710] The results of mass analysis of monomer A1 are shown below.

[0711] MASS:279.1[M+H] +

[0712] [Examples 1-2 to 1-8] Synthesis of Monomers A2 to A8

[0713] Various polymerizable monomers are synthesized by using corresponding raw materials and various organic synthesis reactions. The structures of polymerizable monomers used in the synthesis of base polymers are shown below.

[0714] [Chemistry 218]

[0715]

[0716] [2] Synthesis of base polymer

[0717] Among the monomers used for synthesis of the base polymer, those other than the monomers A1 to A8 are as follows.

[0718] [Chemistry 219]

[0719]

[0720] [Chemistry 220]

[0721]

[0722] [Chemistry 221]

[0723]

[0724] [Chemistry 222]

[0725]

[0726] [Chemistry 223]

[0727]

[0728] [Chemistry 224]

[0729]

[0730] [Example 2-1] Synthesis of polymer P-1

[0731] Under nitrogen atmosphere, monomer A1 (8.1 g), monomer a1-1 (9.7 g), monomer b2-1 (6.2 g), monomer c-1 (16.1 g), 1.68 g of V-601 (produced by Wako Pure Chemical Industries, Ltd.) and 50 g of MEK were taken into a flask to prepare a monomer-polymerization initiator solution. 19 g of MEK was taken into another flask under nitrogen atmosphere, heated to 80°C while stirring, and then the above-mentioned monomer-polymerization initiator solution was added dropwise over 4 hours. After the addition was completed, the temperature of the polymerization liquid was maintained at 80°C, stirring was continued for 2 hours, and then cooled to room temperature. The obtained polymerization liquid was added dropwise to 1,200 g of hexane that was vigorously stirred, and the precipitated polymer was filtered. In addition, the obtained polymer was washed twice with 240 g of hexane, and then vacuum dried at 50°C for 20 hours to obtain a white powder polymer P-1 (yield 39.2 g, yield 98%). The Mw of polymer P-1 was 9,300, and Mw / Mn was 1.79. Mw is a polystyrene-equivalent measurement value obtained by GPC using DMF as a solvent.

[0732] [Chemistry 225]

[0733]

[0734] [Examples 2-2 to 2-34, Comparative Examples 1-1 to 1-16] Synthesis of Polymers P-2 to P34, CP-1 to CP-16

[0735] The base polymers shown in Tables 1 and 2 were synthesized in the same manner as in Example 2-1 except that the types and blending ratios of the monomers were changed.

[0736] [Table 1]

[0737]

[0738] [Table 2]

[0739]

[0740]

[0741] [3] Preparation of chemically amplified resist compositions

[0742] [Examples 3-1 to 3-34, Comparative Examples 2-1 to 2-16]

[0743] The base polymer (P-1 to P-34) of the present invention, the comparison base polymer (CP-1 to CP-16), the photoacid generator (PAG-X to PAG-Y), and the quencher (SQ-1 to SQ-3, AQ-1) were dissolved in a solvent containing 0.01 mass % of surfactant A (Omnova) according to the compositions shown in Tables 3 and 4 below to prepare a solution, and the solution was filtered with a 0.2 μm Teflon (registered trademark) filter to prepare a chemically amplified resist composition (R-1 to R-34, CR-1 to CR-16).

[0744] [Table 3]

[0745]

[0746]

[0747] [Table 4]

[0748]

[0749]

[0750] In Tables 3 and 4, the components are as follows.

[0751] Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0752] DAA (Diacetone Alcohol)

[0753] Photoacid generator: PAG-X, PAG-Y

[0754] [Chemistry 226]

[0755]

[0756] Quenching agent: SQ-1~SQ-3, AQ-1

[0757] [Chemistry 227]

[0758]

[0759] Surfactant A: 3-methyl-3-(2,2,2-trifluoroethoxymethyl)oxetane / tetrahydrofuran / 2,2-dimethyl-1,3-propanediol copolymer (manufactured by Omnova)

[0760] [Chemistry 228]

[0761]

[0762] a:(b+b'):(c+c')=1:4~7:0.01~1 (molar ratio)

[0763] Mw=1500

[0764] [4]EUV lithography evaluation (1)

[0765] [Examples 4-1 to 4-34, Comparative Examples 3-1 to 3-16]

[0766] Each chemically amplified resist composition (R-1 to R-34, CR-1 to CR-16) shown in Tables 3 and 4 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 at 100° C. for 60 seconds using a hot plate to prepare a resist film with a film thickness of 50 nm. This was exposed by an EUV scanning exposure machine NXE3300 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 5 and 6. Thereafter, immersion development was performed for 30 seconds with a 2.38 mass % TMAH aqueous solution, eluted with an elution material containing a surfactant, and spin-dried to obtain a positive pattern.

[0767] The LS pattern was observed by Hitachi Advanced Technologies Co., Ltd.'s CG6300 SEM, and the sensitivity, exposure margin (EL), LWR, depth of focus (DOF), and collapse limit were evaluated according to the following methods. The results are shown in Tables 5 and 6.

[0768] [Sensitivity evaluation]

[0769] Find the optimal exposure E to obtain a LS pattern with a line width of 18nm and a pitch of 36nm op (mJ / cm 2 ), which is defined as the sensitivity. The smaller this value is, the higher the sensitivity is.

[0770] [EL evaluation]

[0771] The EL (unit: %) is calculated from the exposure amount formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm pitch width of the LS pattern as follows. The larger the value, the better the performance.

[0772] EL(%)=(|E 1 -E 2| / E op )×100

[0773] E 1 : Optimal exposure for LS pattern with line width of 16.2nm and pitch of 36nm

[0774] E 2 : Optimal exposure for LS pattern with line width of 19.8nm and pitch of 36nm

[0775] E op : Optimal exposure for LS pattern with line width of 18nm and pitch of 36nm

[0776] [LWR evaluation]

[0777] For E op The LS pattern measurement line dimensions at 10 points in the longitudinal direction were obtained by irradiation, and the value (3σ) tripled by the standard deviation (σ) was calculated as LWR from the result. The smaller this value is, the smaller the roughness and the uniform line width pattern is obtained.

[0778] [DOF evaluation]

[0779] For the evaluation of the depth of focus, the focal range formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm size of the LS pattern is determined. The larger this value is, the wider the depth of focus is.

[0780] [Evaluation of Collapse Limit of Line Pattern]

[0781] The line size of each exposure amount at the optimal focus of the LS pattern is measured at 10 points in the longitudinal direction. The thinnest line size obtained without collapse is defined as the collapse limit size. The smaller this value is, the better the collapse limit is.

[0782] [Table 5]

[0783]

[0784]

[0785] [Table 6]

[0786]

[0787] From the results shown in Tables 5 and 6, it is known that the chemically amplified resist composition containing the photoacid generator of the present invention has good sensitivity and excellent EL, LWR and DOF. In addition, it was confirmed that the value of the collapse limit is small, and the pattern collapse can be resisted even in fine pattern formation. Therefore, the chemically amplified resist composition representing the present invention is suitable as a material for EUV lithography.

[0788] [5]EUV lithography evaluation (2)

[0789] [Examples 5-1 to 5-34, Comparative Examples 4-1 to 4-16]

[0790] Each chemically amplified resist composition (R-1 to R-34, CR-1 to CR-16) shown in Tables 3 and 4 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 at 105° C. for 60 seconds using a hot plate to prepare a resist film with a film thickness of 50 nm. This was exposed using an EUV scanner exposure machine NXE3400 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask with a hole pattern having a size of 46 nm pitch and a deviation of +20% on the wafer), and PEB was performed for 60 seconds using a hot plate at the temperature described in Tables 7 and 8, and developed with a 2.38% by mass TMAH aqueous solution for 30 seconds to form a hole pattern having a size of 23 nm.

[0791] The exposure amount when the hole size is formed at 23nm was measured using a Hitachi Advanced Technologies Co., Ltd.-made length measurement SEM (CG6300), which was defined as sensitivity. In addition, the hole sizes of 50 holes were measured at this time, and the 3-fold value (3σ) of the standard deviation (σ) was calculated from the results, which was defined as the dimension variation (CDU). The results are shown in Tables 7 and 8.

[0792] [Table 7]

[0793]

[0794]

[0795] [Table 8]

[0796]

[0797] From the results shown in Tables 7 and 8, it was confirmed that the chemically amplified resist composition of the present invention had good sensitivity and excellent CDU.

[0798] [6] Evaluation of dry etching resistance

[0799] [Examples 6-1 to 6-34, Comparative Examples 5-1 to 5-16]

[0800] 2 g of each base polymer (P-1 to P-34, CP-1 to CP-16) shown in Tables 1 and 2 was dissolved in 10 g of cyclohexanone, filtered with a 0.2 μm filter, and the polymer solution was spin-coated on a 152 mm square blank mask with a Cr film on the outermost surface to form a film with a thickness of 300 nm. The film was evaluated under the following conditions.

[0801] Etching test with chlorine gas:

[0802] Using a mask dry etching apparatus Gen-4 manufactured by Plasma-Therm, the difference in film thickness of the polymer film before and after etching was determined.

[0803] The etching conditions are as follows.

[0804]

[0805] In this evaluation, a film with a smaller film thickness difference, that is, a film with a smaller reduction amount, shows good etching resistance.

[0806] The results of dry etching resistance are shown in Tables 9 and 10.

[0807] [Table 9]

[0808]

[0809]

[0810] [Table 10]

[0811]

[0812]

[0813] From the results shown in Tables 9 and 10, it was confirmed that the polymer of the present invention has 2 / O 2 The system gas has excellent dry etching resistance.

Claims

1. A monomer represented by the following formula (A), In the formula, a1 is 1 or 2, a2 ​​is an integer from 0 to 4, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R 1 is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. When a2 ≥ 2, multiple R 1 They can also bond to each other and to the carbon atoms to which they are bonded to form rings. L A is a single bond, an ether bond, an ester bond, an amide 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, R L1 , R L2 and R L3 Each independently represents a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom, R L1 , R L2 and R L3 Any two of them may be bonded to each other and form a ring together with the carbon atoms to which they are bonded. When the aforementioned ring is not formed, R L1 , R L2 and R L3 At least one of the above has at least one structure selected from the group consisting of a multiple bond, an alicyclic ring, and an aromatic ring.

2. The monomer according to claim 1, represented by the following formula (A1), In the formula, a2, R A , R 1 , L A , X L and R L1 ~R L3 Same as above.

3. The monomer according to claim 2, represented by the following formula (A2), In the formula, a2, R A , R 1 and R L1 ~R L3 Same as above.

4. A polymer comprising repeating units derived from the monomer according to claim 1.

5. The polymer according to claim 4, further comprising at least one selected from the group consisting of a repeating unit represented by the following formula (a1) and a repeating unit represented by the following formula (a2), In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X 1 is a single bond, phenylene, naphthylene, *-C(=O)-OX 11 - or *-C(=O)-NH-X 11 -, the phenylene group or naphthylene group may be substituted by an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom or a halogen atom, X 11 is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring, X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * indicates the atomic bond between the carbon atoms 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 1 and AL 2 are each independently an acid-labile group, a3 is an integer from 0 to 4.

6. The polymer according to claim 4, further comprising at least one selected from the group consisting of a repeating unit represented by the following formula (b1) and a repeating unit represented by the following formula (b2), In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, Y 1 is a single bond or *-C(=O)-O-, * represents an atomic bond with a carbon atom of the main chain, R 21 is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one structure selected from the group consisting of a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-), 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, b1 is an integer from 1 to 4, b2 is an integer from 0 to 4, but 1≤b1+b2≤5.

7. The polymer according to claim 4, further comprising 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 is a divalent group obtained by an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a combination thereof, and may 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, wherein the aliphatic alkylene group may 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 a hetero atom, 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 a hetero atom, 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 contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group, * indicates the atomic bond between the carbon atoms in the main chain, and ** indicates the bond between Z 1 Atomic bonds, *** indicates and Z 3 Atomic bonds, **** indicates and Z 4 The atomic bonds R 31 and R 32 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and R 31 and R 32 They can also bond to each other and to the sulfur atoms to which they are bonded to form a ring. L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond, R 1 and Rf 2 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, R 3 and Rf 4 are each 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, but not all Rf 5 and Rf 6 At the same time, it becomes a hydrogen atom, M - is a non-nucleophilic counter ion, A + is an onium cation, c1 and c2 are each independently an integer of 0-3. 8 . A chemically amplified resist composition comprising a base polymer containing the polymer according to claim 4 , and an organic solvent. 9 . The chemically amplified resist composition according to claim 8 , further comprising a quencher. 10 . The chemically amplified resist composition according to claim 8 , further comprising a photoacid generator.

11. The chemically amplified resist composition according to claim 8, further comprising a surfactant.

12. A pattern forming method comprising the following steps: forming a resist film on a substrate using the chemically amplified resist composition according to claim 8, exposing the resist film to high energy radiation, and The exposed resist film is developed using a developer.

13. The pattern forming method according to claim 12, wherein: The high-energy radiation is KrF excimer laser, ArF excimer laser, electron beam or extreme ultraviolet radiation having a wavelength of 3 to 15 nm.

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