Onium salt type monomer, polymer, chemically amplified resist composition, and pattern forming method

Abstract

The invention relates to an onium salt type monomer, a polymer, a chemically amplified resist composition and a pattern forming method. Provided is an onium salt-type monomer that is used in a chemically amplified resist composition that has excellent solvent solubility, high sensitivity, high contrast, excellent lithography performance such as exposure margin (EL), LWR, CDU, and depth of focus (DOF) in optical lithography using high-energy rays, and that can be used in a chemically amplified resist composition that has excellent photolithography performance such as high-energy rays. Meanwhile, pattern collapse resistance and etching resistance are excellent when a fine pattern is formed. The invention also provides a polymer containing a repeating unit derived from the onium salt type monomer, a chemically amplified resist composition containing the polymer, and a pattern forming method using the chemically amplified resist composition. An onium salt type monomer represented by formula (a). # imgabs0 #

Description

Technical Field

[0001] The invention relates to an onium salt type 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. In particular, the expansion of the flash memory market and the increase in memory capacity are leading the miniaturization. As the most advanced miniaturization technology, mass production of 65nm node devices using ArF lithography has been carried out, and preparations for mass production of 45nm node devices using ArF immersion lithography for the next generation are underway. As the next generation of 32nm node devices, immersion lithography using ultra-high NA lenses that combines liquids with a higher refractive index than water and high refractive index lenses, high refractive index resist films, extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm, and double exposure (double patterning lithography) of ArF lithography are candidates and are being studied.

[0003] As miniaturization progresses and approaches the diffraction limit of light, the contrast of light gradually decreases. Due to the decrease in light contrast, the resolution of hole patterns and trench patterns and the focus latitude of the positive resist film decrease.

[0004] The miniaturization of patterns, the line width roughness (LWR) of line patterns, and the size uniformity (CDU) of hole patterns are considered to be problems. Some people point out the influence of the concentration of base polymers and acid generators, the influence of agglomeration, and the influence of acid diffusion. In addition, with the thinning of resist films, there is a tendency for LWR to increase, and the deterioration of LWR caused by the thinning accompanying miniaturization has become a serious problem.

[0005] EUV photolithography resist compositions must simultaneously achieve high sensitivity, high resolution, and low LWR. Shortening the acid diffusion distance reduces LWR but reduces sensitivity. For example, lowering the post-exposure bake (PEB) temperature will reduce LWR but reduce sensitivity. Increasing the amount of quencher added will also reduce LWR, but reduce sensitivity. The trade-off between sensitivity and LWR needs to be broken.

[0006] In order to suppress acid diffusion, a scheme of a resist compound containing a repeating unit of an onium salt of a sulfonic acid having a polymerizable unsaturated bond has been proposed (Patent Document 1). Such a so-called polymer-bonded acid generator has the characteristic of very short acid diffusion because it generates polymer-type sulfonic acid upon exposure. In addition, by increasing the ratio of the acid generator, the sensitivity can also be improved. If the additive acid generator is increased in amount, the sensitivity will increase, but in this case, the acid diffusion distance will also increase. The acid will diffuse unevenly, so if the acid diffusion increases, the LWR and CDU will deteriorate. In terms of the balance of sensitivity, LWR and CDU, it can be said that the polymer-type acid generator has high ability.

[0007] Iodine atoms have a very large absorption of EUV at a wavelength of 13.5 nm, so the effect of generating secondary electrons from iodine atoms during exposure has been confirmed, and it has attracted attention in EUV lithography. Patent Document 2 describes a photoacid generator in which iodine atoms are introduced into anions, and Patent Document 3 describes a photoacid generator containing a polymerizable group in which iodine atoms are introduced into anions. This can confirm that there is a certain degree of improvement in lithography performance, but the solubility of iodine atoms in organic solvents is not high, and there is a concern that they will precipitate in the solvent.

[0008] Prior art literature

[0009] Patent Literature

[0010] [Patent Document 1] Japanese Patent No. 4425776

[0011] [Patent Document 2] Japanese Patent No. 6720926

[0012] [Patent Document 3] Japanese Patent No. 6973274 Summary of the invention

[0013] [Problems to be solved by the invention]

[0014] In a chemically amplified resist composition using an acid as a catalyst, it is desired to develop a resist composition that has a higher sensitivity, can improve the LWR of lines and the CDU of holes, and also has excellent etching resistance after patterning.

[0015] In view of the above circumstances, the present invention aims to provide an onium salt monomer used in a chemically amplified resist composition, a polymer containing a repeating unit derived from the onium salt monomer, a chemically amplified resist composition containing the polymer, and a pattern forming method using the chemically amplified resist composition, which has excellent solvent solubility, high sensitivity, high contrast, and excellent lithography performance such as exposure margin (EL), LWR, CDU, and depth of focus (DOF), especially in optical lithography using high-energy rays such as KrF excimer laser, ArF excimer laser, electron beam (EB), and EUV, and is resistant to pattern collapse and excellent in etching resistance during fine pattern formation.

[0016] [Methods for solving problems]

[0017] The inventors of the present application have made great efforts to achieve the above-mentioned purpose and have found that a chemically amplified resist composition having high sensitivity, improved LWR and CDU, high contrast and high resolution, and excellent etching resistance can be obtained by using a polymer derived from a repeating unit containing the following onium salt as a polymer-bound acid generator, thereby completing the present invention. The onium salt has a styrene or vinylnaphthalene structure as a polymerizable group and contains a fluorosulfonic acid anion having an aromatic ring structure substituted with an iodine atom.

[0018] That is, the present invention provides the following onium salt type monomer, polymer, chemically amplified resist composition and pattern forming method.

[0019] 1. An onium salt type monomer represented by the following formula (a),

[0020] [Chemistry 1]

[0021]

[0022] In the formula, n1 is 0 or 1. n2 is 0 or 1. n3 is an integer of 0 to 4. n4 is an integer of 0 to 4. n5 is an integer of 1 to 6. However, when n2 is 0, 1≤n4+n5≤4, and when n2 is 1, 1≤n4+n5≤6. n6 is an integer of 0 to 4.

[0023] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0024] 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.

[0025] R 2 is a halogen atom other than an iodine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. When n4 is 2, 3 or 4, a plurality of R 2 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring.

[0026] L A , L B and L C Each is independently a single bond, an ether bond, an ester bond, a sulfonate bond, a sulfonamide 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] Q 1 and Q 2Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0029] Q 3 and Q 4 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0030] Z + It is an onium cation.

[0031] 2. The onium salt type monomer as in 1. is represented by the following formula (a1),

[0032] [Chemistry 2]

[0033]

[0034] In the formula, n1~n6, R A , R 1 , R 2 , L A , L C , Q 1 ~Q 4 and Z + Same as above.

[0035] 3. The onium salt type monomer as in 2. is represented by the following formula (a2),

[0036] [Chemistry 3]

[0037]

[0038] In the formula, n1~n6, R A , R 1 , R 2 , L A , Q 1 , Q 2 and Z + Same as above.

[0039] 4. The onium salt-type monomer according to any one of 1. to 3., wherein Z + is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2),

[0040] [Chemistry 4]

[0041]

[0042] In the formula, R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. ct1 and R ct2They may also bond to each other and to the sulfur atom to which they are bonded to form a ring.

[0043] 5. A polymer comprising a repeating unit derived from the onium salt type monomer according to any one of 1. to 4.

[0044] 6. The polymer of 5. further comprises a repeating unit represented by the following formula (b1) or (b2),

[0045] [Chemistry 5]

[0046]

[0047] In the formula, R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0048] 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.

[0049] X 2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-.

[0050] *Indicates atomic bonds to carbon atoms in the main chain.

[0051] AL 1 and AL 2 Each is independently an acid-labile group.

[0052] R 11 It is a halogen atom, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a 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.

[0053] a is an integer from 0 to 4.

[0054] 7. The polymer of 5. or 6. further comprises a repeating unit represented by the following formula (c1):

[0055] [Chemistry 6]

[0056]

[0057] In the formula, RA is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0058] Y 1 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond with a carbon atom of the main chain.

[0059] R 21 It is a halogen atom, a nitro group, 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.

[0060] c is an integer from 1 to 4. d is an integer from 0 to 3. However, 1≤c+d≤5.

[0061] 8. The polymer according to any one of 5. to 7., further comprising a repeating unit represented by the following formula (d1):

[0062] [Chemistry 7]

[0063]

[0064] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0065] Z 1 is a single bond, phenylene, naphthylene, *-C(=O)-OZ 11 - or *-C(=O)-NH-Z 11 -, or 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. * represents an atomic bond with a carbon atom of the main chain. Z 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.

[0066] R 31 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)-).

[0067] 9. A chemically amplified resist composition comprising (A) a base polymer comprising the polymer according to any one of 5. to 8.

[0068] 10. The chemically amplified resist composition of 9. further comprises (B) an organic solvent.

[0069] 11. The chemically amplified resist composition of 9. or 10. further comprises (C) a quencher.

[0070] 12. The chemically amplified resist composition according to any one of 9. to 11., further comprising (D) an acid generator.

[0071] 13. The chemically amplified resist composition according to any one of 9. to 12., further comprising (E) a surfactant.

[0072] 14. The chemically amplified resist composition according to any one of 9. to 13., further comprising (F) a dissolution inhibitor.

[0073] 15. A pattern forming method comprising the following steps:

[0074] Using the chemically amplified resist composition according to any one of 9. to 14., forming a resist film on a substrate,

[0075] exposing the resist film to high energy radiation, and

[0076] The exposed resist film is developed using a developer.

[0077] 16. The pattern forming method according to 15., wherein the high-energy radiation is an ArF excimer laser with a wavelength of 193 nm, a KrF excimer laser with a wavelength of 248 nm, an electron beam, or an extreme ultraviolet radiation with a wavelength of 3 to 15 nm.

[0078] [Effects of the Invention]

[0079] The resist film containing a polymer containing repeating units from an onium salt-type monomer represented by formula (a) has good solvent solubility and the atomic weight of the iodine atom is large, so it has the characteristic of small acid diffusion. Thereby, the reduction of resolution due to blurring due to acid diffusion can be prevented, and LWR and CDU can be improved. In addition, since the absorption of EUV with a wavelength of 13.5nm caused by iodine atoms is very large, secondary electrons are generated from iodine atoms during exposure and the sensitivity is improved. Thereby, the sensitivity is high, and a chemically amplified resist composition with improved LWR and CDU can be constructed. In addition, the aromatic ring can act as a good etching resistance group, which is suitable for fine pattern formation. DETAILED DESCRIPTION

[0080] [Onium salt type monomer]

[0081] The onium salt type monomer of the present invention is represented by the following formula (a).

[0082] [Chemistry 8]

[0083]

[0084] In formula (a), n1 is 0 or 1. When n1 is 0, it is a benzene ring, and when n1 is 1, it is a naphthalene ring. In view of solvent solubility, the benzene ring in which n1 is 0 is preferred. n2 is 0 or 1. When n2 is 0, it is a benzene ring, and when n2 is 1, it is a naphthalene ring. In view of solvent solubility, the benzene ring in which n2 is 0 is preferred. n3 is an integer of 0 to 4. In view of raw material scheduling, n3 is preferably 0, 1 or 2, and more preferably 0 or 1. n4 is an integer of 0 to 4, but 0, 1, 2 or 3 is preferred, 0, 1 or 2 is more preferred, and 0 or 1 is more preferred. n5 is an integer of 1 to 6. The more iodine atoms there are in the anion structure, the better the absorption, especially for EUV, but the solvent solubility is poor, and there is a concern of precipitation in the resist composition, so n5 is preferably 1, 2 or 3, and more preferably 1 or 2. However, when n2 is 0, 1≤n4+n5≤4, and when n2 is 1, 1≤n4+n5≤6. n6 is an integer of 0 to 4, preferably 0, 1, 2 or 3, and more preferably 1.

[0085] In formula (a), R A It is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Among them, a hydrogen atom and a methyl group are preferred, and a hydrogen atom is more preferred.

[0086] In formula (a), the iodine atom in the aromatic ring of the anion is preferably bonded to L B The ortho position of the carbon atom to which the bond is bonded is preferred. The iodine atom is an element with a large atomic radius, so the rotation of the bond axis between the aromatic ring to which the polymerizable group is bonded and the aromatic ring to which the iodine atom is bonded is suppressed, and the rigidity of the polymer is improved.

[0087] In formula (a), R 1is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and more preferably a fluorine atom or an iodine atom. The 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, allyl, propenyl, butenyl and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 2 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl and 2-phenylethyl; groups obtained by combining these groups, etc. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. may be contained. When n3 is 2, 3, or 4, each R 1 They may be the same as or different from each other.

[0088] When n3 is 2, 3 or 4, multiple R 1 They may also be bonded to each other and form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed in this case include cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, norbornane ring, adamantane ring, etc. In addition, part or all of the hydrogen atoms in the aforementioned ring may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and part of -CH2- in the aforementioned ring may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may also be contained.

[0089] In formula (a), R 2 is a halogen atom other than an iodine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Specific examples of the halogen atom other than the iodine atom are a fluorine atom, a chlorine atom, a bromine atom, etc. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include and1 The hydrocarbon groups represented are exemplified by the same examples, but are not limited thereto. When n4 is 2, 3 or 4, each R 2 They may be the same as or different from each other.

[0090] When n4 is 2, 3 or 4, multiple R 2 They may also be bonded to each other and to form a ring together with the carbon atom to which they are bonded. The aforementioned ring is preferably a 5- to 8-membered ring.

[0091] In formula (a), L A , L B and L C Each is independently a single bond, an ether bond, an ester bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond. A It is preferably a single bond, an ether bond, an ester bond or a sulfonate bond, and more preferably an ester bond or a sulfonate bond. B It is preferably a single bond, an ether bond or an ester bond, and more preferably a single bond. C It is preferably a single bond, an ether bond, an ester bond or a sulfonate bond, and more preferably an ether bond or an ester bond.

[0092] In formula (a), X L A alkylene group having 1 to 40 carbon atoms and a single bond or optionally containing a hetero atom. The alkylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl, cyclic saturated alkylene, and arylene. Specific examples of the hetero atom include oxygen, nitrogen, and sulfur atoms.

[0093] 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 L B of atomic bonds.

[0094] [Chemistry 9]

[0095]

[0096] [Chemistry 10]

[0097]

[0098] [Chemistry 11]

[0099]

[0100] [Chemistry 12]

[0101]

[0102] Among these, X L -0~X L -22, XL -29~X L -34, and X L -47~X L -58 is better.

[0103] Considering the rigidity of the obtained polymer, X L A single bond is preferred.

[0104] In formula (a), Q 1 and Q 2 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms is preferably a trifluoromethyl group.

[0105] In formula (a), Q 3 and Q 4 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms is preferably a trifluoromethyl group. 3 and Q 4 A fluorine atom is more preferred.

[0106] In formula (a), -[C(Q 1 )(Q 2 )] n4 -C(Q 3 )(Q 4 )-SO3 - Specific examples of the partial structure represented by are preferably shown below, but are not limited to these. In the following formula, * represents and L C of atomic bonds.

[0107] [Chemistry 13]

[0108]

[0109] Among these, Acid-1 to Acid-7 are preferred, and Acid-1 to Acid-3, Acid-6 and Acid-7 are more preferred.

[0110] The onium salt type monomer represented by the formula (a) is preferably represented by the following formula (a1).

[0111] [Chemistry 14]

[0112]

[0113] In the formula, n1~n6, R A , R 1 , R 2 , L A , L C , Q 1 ~Q 4 and Z +Same as above.

[0114] The onium salt type monomer represented by formula (a1) is preferably represented by the following formula (A2).

[0115] [Chemistry 15]

[0116]

[0117] In the formula, n1~n6, R A , R 1 , R 2 , L A , Q 1 , Q 2 and Z + Same as above.

[0118] Specific examples of anions of the onium salt-type monomers represented by formula (a) include the following, but are not limited thereto. A and Q 1 As mentioned above, Me is a methyl group. In addition, the bonding positions of various substituents on the aromatic ring may be interchanged.

[0119] [Chemistry 16]

[0120]

[0121] [Chemistry 17]

[0122]

[0123] [Chemistry 18]

[0124]

[0125] [Chemistry 19]

[0126]

[0127] [Chemistry 20]

[0128]

[0129] [Chemistry 21]

[0130]

[0131] [Chemistry 22]

[0132]

[0133] [Chemistry 23]

[0134]

[0135] [Chemistry 24]

[0136]

[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] [Chemistry 65]

[0218]

[0219] [Chemistry 66]

[0220]

[0221] [Chemistry 67]

[0222]

[0223] [Chemistry 68]

[0224]

[0225] [Chemistry 69]

[0226]

[0227] [Chemistry 70]

[0228]

[0229] [Chemistry 71]

[0230]

[0231] [Chemistry 72]

[0232]

[0233] In formula (1), Z + The onium cation is preferably a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2).

[0234] [Chemistry 73]

[0235]

[0236] 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.

[0237] R ct1 ~R ct5 Specific examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.

[0238] R ct1 ~R ct5The hydrocarbon group represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 30 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 30 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them, among which aryl groups are preferred. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, the hydrocarbon group may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0239] 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. Specific examples of the structure of the ring include those represented by the following formula.

[0240] [Chemistry 74]

[0241]

[0242] In the formula, the chain line is and R ct3 of atomic bonds.

[0243] Specific examples of the sulfonium cation represented by the formula (cation-1) include the following, but are not limited to these.

[0244] [Chemistry 75]

[0245]

[0246] [Chemistry 76]

[0247]

[0248] [Chemistry 77]

[0249]

[0250] [Chemistry 78]

[0251]

[0252] [Chemistry 79]

[0253]

[0254] [Chemistry 80]

[0255]

[0256] [Chemistry 81]

[0257]

[0258] [Chemistry 82]

[0259]

[0260] [Chemistry 83]

[0261]

[0262] [Chemistry 84]

[0263]

[0264] [Chemistry 85]

[0265]

[0266] [Chemistry 86]

[0267]

[0268] [Chemistry 87]

[0269]

[0270] [Chemistry 88]

[0271]

[0272] [Chemistry 89]

[0273]

[0274] [Chemistry 90]

[0275]

[0276] [Chemistry 91]

[0277]

[0278] [Chemistry 92]

[0279]

[0280] [Chemistry 93]

[0281]

[0282] [Chemistry 94]

[0283]

[0284] [Chemistry 95]

[0285]

[0286] [Chemistry 96]

[0287]

[0288] [Chemistry 97]

[0289]

[0290] [Chemistry 98]

[0291]

[0292] [Chemistry 99]

[0293]

[0294] [Chemical 100]

[0295]

[0296] [Chemistry 101]

[0297]

[0298] Specific examples of the iodonium cation represented by the formula (cation-2) include the following, but are not limited to these.

[0299] [Chemistry 102]

[0300]

[0301] [Chemistry 103]

[0302]

[0303] Specific examples of the onium salt-type monomer represented by formula (a) include any combination of the above-mentioned anions and cations.

[0304] The onium salt type monomer represented by formula (a) can be synthesized, for example, in the same manner as the sulfonium salt having a polymerizable anion described in Japanese Patent No. 5201363, but is not limited thereto.

[0305] [polymer]

[0306] The polymer of the present invention contains a repeating unit derived from an onium salt-type monomer represented by formula (a) (hereinafter also referred to as a repeating unit A).

[0307] The polymer of the present invention is a polymer-bonded photoacid generator that acts as a photoacid generator in a chemically amplified resist composition and also acts as a base polymer. The structural characteristics of the polymer of the present invention include, for example, a repeating unit having an onium salt structure, wherein the onium salt structure contains a fluorosulfonic acid anion having a benzene or naphthalene structure directly bonded to the main chain and having an aromatic ring structure substituted by an iodine atom, which is derived from the onium salt-type monomer of the present invention. Iodine atoms have a great absorption of EUV with a wavelength of 13.5 nm, so secondary electrons are generated during exposure, and the energy of the secondary electrons moves to the acid generator, thereby promoting decomposition and improving sensitivity. The polymerizable group composed of styrene and vinylnaphthalene structures is more rigid than polymerizable groups such as methacrylate, and increases the glass transition temperature (Tg) of the polymer. The aromatic rings within or between the base polymers are arranged in a correct order by interaction (π-π stacking effect), and it is believed that the base polymer will show resistance to pattern collapse in the developer when a fine pattern is formed. In addition, the etching step after the fine pattern is formed will show excellent etching resistance by having an aromatic ring directly bonded to the main chain. In the aromatic ring substituted with iodine atoms, the iodine atom is preferably substituted at the ortho position of the carbon atom bonded to the polymerizable group, thereby, it can be expected that the rotation of the bond axis between the aromatic ring of the polymerizable group and the aromatic ring substituted with iodine atoms is suppressed. Therefore, excessive acid diffusion of the generated acid can be suppressed, and a pattern with excellent LWR of the line pattern and CDU of the hole pattern and resistance to pattern collapse can be formed, so it is particularly suitable as a material for a chemically amplified positive resist composition.

[0308] The aforementioned polymer may further contain a repeating unit represented by the following formula (b1) (hereinafter also referred to as repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit b2).

[0309] [Chemistry 104]

[0310]

[0311] In formula (b1) and (b2), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0312] In formula (b1), 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. 11It is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group. The saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. * represents an atomic bond to a carbon atom of the main chain.

[0313] In formula (b2), X 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. a is an integer of 0 to 4, preferably 0 or 1.

[0314] In formula (b1) and (b2), AL 1 and AL 2 Each independently represents an acid-labile group. Specific examples of the acid-labile group include, but are not limited to, those described in Japanese Unexamined Patent Publication Nos. 2013-80033 and 2013-83821.

[0315] In general, specific examples of the acid-labile group are represented by the following formulae (AL-1) to (AL-3).

[0316] [Chemistry 105]

[0317]

[0318] In the formula, * is an atomic bond.

[0319] In formula (AL-1) and (AL-2), R L1 and R L2 Each is independently a hydrocarbon group having 1 to 40 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, fluorine atoms, and iodine atoms. The hydrocarbon group may be straight-chain, branched, or cyclic. The hydrocarbon group preferably has 1 to 20 carbon atoms.

[0320] In the formula (AL-1), b is an integer of 0 to 10, preferably an integer of 1 to 5.

[0321] In formula (AL-2), R L3 and R L4 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, fluorine atoms, and iodine atoms. The hydrocarbon group may be straight-chain, branched, or cyclic. L2 , R L3 and R L4Any 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.

[0322] In formula (AL-3), R L5 , R L6 and R L7 Each is independently a hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, fluorine atoms, and iodine atoms. The hydrocarbon group may be linear, branched, or cyclic. L5 , R L6 and R L7 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.

[0323] Specific examples of the repeating unit b1 include the following, but are not limited to these. A and AL 1 Same as above.

[0324] [Chemistry 106]

[0325]

[0326] [Chemistry 107]

[0327]

[0328] [Chemistry 108]

[0329]

[0330] [Chemistry 109]

[0331]

[0332] [Chemistry 110]

[0333]

[0334] [Chemistry 111]

[0335]

[0336] [Chemistry 112]

[0337]

[0338] Specific examples of the repeating unit b2 include the following, but are not limited to these. A and AL 2 Same as above.

[0339] [Chemistry 113]

[0340]

[0341] [Chemistry 114]

[0342]

[0343] [Chemistry 115]

[0344]

[0345] The base polymer preferably further contains a repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit c).

[0346] [Chemistry 116]

[0347]

[0348] In formula (c1), R A Y is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond with a carbon atom of the main chain. 21 is a halogen atom, a nitro group, 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. c is an integer of 1 to 4. d is an integer of 0 to 3. However, 1≤c+d≤5.

[0349] Specific examples of the repeating unit c are listed below, but are not limited to these. A Same as above.

[0350] [Chemistry 117]

[0351]

[0352] [Chemistry 118]

[0353]

[0354] [Chemistry 119]

[0355]

[0356] [Chemistry 120]

[0357]

[0358] [Chemistry 121]

[0359]

[0360] The base polymer preferably further contains a repeating unit represented by the following formula (d1) (hereinafter also referred to as repeating unit d).

[0361] [Chemistry 122]

[0362]

[0363] In formula (d1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 is a single bond, phenylene, naphthylene, *-C(=O)-OZ 11 - or *-C(=O)-NH-Z 11 -, or 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. * represents an atomic bond with a carbon atom of the main chain. Z 11 R 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. 31 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)-).

[0364] Specific examples of the repeating unit d are listed below, but are not limited to these. A Same as above.

[0365] [Chemistry 123]

[0366]

[0367] [Chemistry 124]

[0368]

[0369] [Chemistry 125]

[0370]

[0371] [Chemistry 126]

[0372]

[0373] [Chemistry 127]

[0374]

[0375] [Chemistry 128]

[0376]

[0377] [Chemistry 129]

[0378]

[0379] [Chemistry 130]

[0380]

[0381] [Chemistry 131]

[0382]

[0383] [Chemistry 132]

[0384]

[0385] [Chemistry 133]

[0386]

[0387] [Chemistry 134]

[0388]

[0389] [Chemistry 135]

[0390]

[0391] [Chemistry 136]

[0392]

[0393] [Chemistry 137]

[0394]

[0395] [Chemistry 138]

[0396]

[0397] As for the repeating unit c or d, those having a lactone ring are particularly preferred in ArF lithography, and those having a phenol moiety are preferred in KrF lithography, EB lithography, and EUV lithography.

[0398] The aforementioned 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 e). The repeating unit e 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, but the one represented by the following formula (e1) is preferred.

[0399] [Chemistry 139]

[0400]

[0401] In formula (e1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 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.

[0402] In formula (e1), 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 an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (e2), etc. are preferred, and an alkoxymethyl group represented by the following formula (e2) is particularly preferred.

[0403] [Chemistry 140]

[0404]

[0405] In the formula, * represents an atomic bond. 43 It is a hydrocarbon group having 1 to 15 carbon atoms.

[0406] R 42 Specific examples of the acid-labile group represented by the formula (e2), the alkoxymethyl group represented by the formula (e2), and the repeating unit e are the same as those exemplified in the description of the repeating unit d described in Japanese Patent Application Laid-Open No. 2020-111564.

[0407] The base polymer may further contain a repeating unit f derived from indene, benzofuran, benzothiophene, vinylnaphthalene, chromone, coumarin, norbornadiene or a derivative thereof. Specific examples of the monomer that gives the repeating unit f include the following, but are not limited thereto.

[0408] [Chemistry 141]

[0409]

[0410] The aforementioned base polymer may further contain a repeating unit g derived from styrene, indane, vinyl pyridine or vinyl carbazole.

[0411] In the polymer of the present invention, the content ratios of the repeating units a, b1, b2, c, d, e, f, and g are preferably 0 < a ≤ 0.4, 0 < b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 < c ≤ 0.6, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.3, 0 ≤ f ≤ 0.3, and 0 ≤ g ≤ 0.3, and more preferably 0 < a ≤ 0.3, 0 < b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 < c ≤ 0.5, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.2, 0 ≤ f ≤ 0.2, and 0 ≤ g ≤ 0.2. However, a + b1 + b2 + c + d + e + f + g ≤ 1.0.

[0412] The weight-average molecular weight (Mw) of the aforementioned polymer is preferably 1000 to 500000, and more preferably 3000 to 100000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no concern about a decrease in resolution due to the inability to ensure the difference in dissolution rates before and after exposure. Also, in the present invention, Mw is a polystyrene conversion measurement value obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent.

[0413] Furthermore, regarding the molecular weight distribution (Mw / Mn) of the aforementioned polymer, as the pattern rules are miniaturized, the influence of Mw / Mn tends to increase. Therefore, in order to obtain a resist composition suitable for use with fine pattern sizes, a narrow dispersion with Mw / Mn of 1.0 to 2.0 is preferred. If it is within the aforementioned range, there are fewer low-molecular-weight and high-molecular-weight polymers, and after exposure, there is no concern about foreign matter appearing on the pattern or the shape of the pattern deteriorating.

[0414] The synthesis method of the aforementioned polymer is, for example, a method of adding a radical polymerization initiator to monomers providing the aforementioned repeating units in an organic solvent and heating to polymerize them.

[0415] Specific examples of the organic solvent used during polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), etc. Specific examples of the aforementioned polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, etc. The addition amount of these initiators 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 more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the perspective of production efficiency.

[0416] The aforementioned polymerization initiator may be added to the aforementioned monomer solution and then supplied to the reactor, or the initiator solution may be prepared separately from the aforementioned monomer solution and each is independently supplied to the reactor. During the waiting time, the polymerization reaction may proceed and ultra-high molecular weight bodies may be generated due to the free radicals generated from the initiator, so from the perspective of quality management, it is better to prepare the monomer solution and the initiator solution independently and add them dropwise. The acid-labile group may be directly introduced into the monomer or may be protected or partially protected after polymerization. In addition, in order to adjust the molecular weight, a known chain transfer agent such as dodecyl mercaptan and 2-mercaptoethanol may also be used in combination. In this case, the amount of these chain transfer agents added is preferably 0.01 to 20 mol% relative to the total of the monomers to be polymerized.

[0417] In the case of a hydroxyl-containing monomer, 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.

[0418] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers can be added to an organic solvent, a free radical polymerization initiator is added and the mixture is heated for polymerization. Acetoxystyrene or acetoxyvinylnaphthalene can also be used, and after polymerization, the acetoxy group is deprotected by alkaline hydrolysis to form polyhydroxystyrene or hydroxyvinylnaphthalene.

[0419] Specific examples of the base used in the alkaline hydrolysis include 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.

[0420] 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.

[0421] The polymer obtained by the above-mentioned manufacturing method can be treated as the final product by the reaction solution obtained by the polymerization reaction, or by adding the polymerization solution to a poor solvent and treating the powder obtained as the final product through a purification step such as a reprecipitation method to obtain a powder. However, considering the operating efficiency and quality stabilization, it is better to treat the polymer solution obtained by dissolving the powder obtained by the purification step in a solvent as the final product.

[0422] Specific examples of the solvent used in this case include ketones such as cyclohexanone and methyl-2-n-pentyl ketone described in paragraphs

[0144] to

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

[0423] 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.

[0424] 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.

[0425] 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 the filtering step of the chemically amplified resist composition is preferably formed by a fluorocarbon called Teflon (registered trademark), a hydrocarbon such as polyethylene, polypropylene or a nylon. 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 pass the solution only 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, the polymer solution or both after the polymerization reaction.

[0426] [Chemically amplified resist composition]

[0427] [(A) Base polymer]

[0428] The chemically amplified resist composition of the present invention contains a base polymer including the above-mentioned polymer as component (A).

[0429] 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 ring-opening metathesis polymer in addition to the aforementioned polymers, and for this purpose, the polymers described in Japanese Patent Application Publication No. 2003-66612 may be used.

[0430] [(B) Organic solvent]

[0431] The chemically amplified resist composition of the present invention may also contain an organic solvent as component (B). The organic solvent (B) is not particularly limited as long as it can dissolve the aforementioned components and the components described below. Specific examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; 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, and mixed solvents thereof.

[0432] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixed solvents thereof are preferred, since they have particularly excellent solubility in the base polymer of the component (A).

[0433] 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.

[0434] [(C) Quencher]

[0435] 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 captures the acid generated by the photoacid generator in the chemically amplified resist composition and prevents the acid from diffusing to the unexposed area to form a desired pattern.

[0436] Specific examples of the quencher (C) include onium salts represented by the following formula (1) or (2).

[0437] [Chemistry 142]

[0438]

[0439] In formula (1), R q1is 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.

[0440] R q1 Specifically, the hydrocarbon group having 1 to 40 carbon atoms represented by the term "alkyl group" includes alkyl groups having 1 to 40 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbon groups having 3 to 40 carbon atoms, such as decyl and adamantyl; aryl groups having 6 to 40 carbon atoms, such as phenyl, naphthyl, anthracenyl, etc. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and part of -CH2- of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may be contained.

[0441] R q2 Specifically, for example, R q1 In addition to the substituents exemplified as specific examples, fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl may be mentioned.

[0442] Specific examples of the anion of the onium salt represented by the formula (1) include the following, but are not limited to these.

[0443] [Chemistry 143]

[0444]

[0445] [Chemistry 144]

[0446]

[0447] [Chemistry 145]

[0448]

[0449] Specific examples of the anion of the onium salt represented by the formula (2) include the following, but are not limited to these.

[0450] [Chemistry 146]

[0451]

[0452] [Chemistry 147]

[0453]

[0454] [Chemistry 148]

[0455]

[0456] In formula (1) and (2), 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).

[0457] [Chemistry 149]

[0458]

[0459] In formula (cation-3), R ct6 ~R ct9 are each independently a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. ct6 and R ct7 They may also be bonded to each other and to form a ring together with the nitrogen atom to which they are bonded. Specific examples of the aforementioned hydrocarbon groups are as described in the formulas (cation-1) and (cation-2). ct1 ~R ct5 The hydrocarbon groups represented are exemplified by the same examples.

[0460] Specific examples of the ammonium cation represented by the formula (cation-3) include the following, but are not limited to these.

[0461] [Chemistry 150]

[0462]

[0463] Specific examples of the onium salt represented by formula (1) or (2) 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 example, the ion exchange reaction can be referred to Japanese Patent Application Publication No. 2007-145797.

[0464] The onium salt represented by formula (1) or (2) acts as a quencher in the chemically amplified resist composition of the present invention. The reason is that each counter anion of the onium salt is a conjugate base of a weak acid. The so-called weak acid here refers to an acid that shows an acidity that cannot deprotect the acid-labile group of the unit containing the acid-labile group of the base polymer. The onium salt represented by formula (1) or (2) 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 α-fluorinated sulfonic acid as a counter anion. That is, when an onium salt that generates a strong acid such as α-fluorinated sulfonic acid is used in combination with an onium salt that generates a weak acid such as unfluorinated sulfonic acid or carboxylic acid, if the strong acid generated from the photoacid generator due to high-energy ray irradiation collides with the onium salt having an unreacted 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, strong acids are exchanged for weaker acids with lower catalytic capacity, so that the acid is deactivated macroscopically and the acid diffusion can be controlled.

[0465] In addition, as the quencher (C), 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 can also be used.

[0466] Here, when the photoacid generator that generates a strong acid is an onium salt, as described above, the strong acid generated by high-energy ray irradiation can be exchanged for a weak acid, but on the other hand, it is considered that salt exchange is not easy to proceed due to collision between the weak acid generated by high-energy ray irradiation and the unreacted onium salt that generates a strong acid. This is due to the phenomenon that the onium cation is more likely to form an ion pair with the anion of the strong acid.

[0467] In the chemically amplified resist composition of the present invention, when an onium salt represented by formula (1) or (2) is contained as the quencher (C), its content is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass relative to 80 parts by mass of the base polymer (A). If the onium salt type quencher of 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 (1) or (2) can be used alone or in combination of two or more.

[0468] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as (C) a quencher. Specific examples of the nitrogen-containing compound of the component (C) include primary, secondary or tertiary amine compounds described in paragraphs

[0146] to

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

[0469] 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.

[0470] 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.

[0471] [(D) Acid generator]

[0472] The chemically amplified resist composition of the present invention may also contain an acid generator within the range that does not impair the effect of the present invention. The aforementioned acid generator is, for example, a compound that generates acid by induction of active light or radiation (photoacid generator). The photoacid generator is not particularly limited as long as it is a compound that generates acid by irradiation with high-energy rays, and is preferably a compound that generates sulfonic acid, imidic acid or methylated acid. Ideal photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc. Specific examples of acid generators are described in paragraphs

[0122] to

[0142] of Japanese Patent Gazette No. 2008-111103.

[0473] Furthermore, as the photoacid generator, a sulfonium salt represented by the following formula (3-1) or an iodonium salt represented by the following formula (3-2) can also be preferably used.

[0474] [Chemistry 151]

[0475]

[0476] In formula (3-1) and (3-2), R 101 ~R 105Each is independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Specific examples of the halogen atom and the hydrocarbon group are as described in the description of formula (cation-1) and (cation-2). ct1 ~R ct5 The halogen atoms and hydrocarbon groups represented by are the same examples. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. In addition, R 101 and R 102 They may also be bonded to each other and to form a ring together with the sulfur atom to which they are bonded. Specific examples of the ring formed in this case are as follows: ct1 and R ct2 The same examples are exemplified for the rings that can be formed together with the sulfur atoms to which they are bonded.

[0477] Specific examples of the cation of the sulfonium salt represented by formula (3-1) 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 (4-2) are the same as those exemplified for the iodonium cation represented by formula (cation-2).

[0478] In formula (3-1) and (3-2), Xa - It is an anion selected from the following formulae (3A) to (3D).

[0479] [Chemistry 152]

[0480]

[0481] In formula (3A), R fa is a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the following R in the formula (3A') described below: fa1 The description exemplifies the same example.

[0482] The anion represented by the formula (3A) is preferably represented by the following formula (3A').

[0483] [Chemistry 153]

[0484]

[0485] In formula (3A'), R HF It is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0486] In formula (3A'), R fa1 It is a hydrocarbon group having 1 to 38 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.

[0487] R fa1 The hydrocarbon group having 1 to 38 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 38 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 38 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 38 carbon atoms, such as allyl and 3-cyclohexenyl; aryl groups having 6 to 38 carbon atoms, such as phenyl, 1-naphthyl and 2-naphthyl; aralkyl groups having 7 to 38 carbon atoms, such as benzyl and diphenylmethyl; groups obtained by combining these groups, etc.

[0488] Furthermore, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. may be contained. Furthermore, it is preferred that the aforementioned hetero atom is an oxygen atom. Specific examples of the hydrocarbon group containing a hetero atom include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, 3-oxocyclohexyl, etc.

[0489] For details on the synthesis of sulfonium salts containing anions represented by formula (3A'), see Japanese Patent Application Publication Nos. 2007-145797, 2008-106045, 2009-7327, 2009-258695, etc. Sulfonium salts described in Japanese Patent Application Publication Nos. 2010-215608, 2012-41320, 2012-106986, 2012-153644, etc. are also preferably used.

[0490] Specific examples of the anion represented by formula (3A) include the following, but are not limited thereto. In the following formula, Ac is an acetyl group.

[0491] [Chemistry 154]

[0492]

[0493] [Chemistry 155]

[0494]

[0495] [Chemistry 156]

[0496]

[0497] [Chemistry 157]

[0498]

[0499] In formula (3B), 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 include: 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 With R fb2 They can also bond to each other and to the groups to which they are bonded (-CF2-SO2-N - -SO2-CF2-) together to form a ring, at this time R fb1 With R fb2 The group obtained by bonding to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0500] In formula (3C), R fc1 , R fc2 and R fc3Each 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 include: 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 With R fc2 They can also bond to each other and to the groups to which they are bonded (-CF2-SO2-C - -SO2-CF2-) together to form a ring, at this time R fc1 With R fc2 The group obtained by bonding to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0501] In formula (3D), 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 include: fa1 The hydrocarbon groups represented are exemplified by the same examples.

[0502] For details on the synthesis of the sulfonium salt containing the anion represented by the formula (3D), see Japanese Patent Application Laid-Open Nos. 2010-215608 and 2014-133723.

[0503] Specific examples of the anion represented by formula (3D) include the following, but are not limited to these.

[0504] [Chemistry 158]

[0505]

[0506] [Chemistry 159]

[0507]

[0508] In addition, the photoacid generator containing the anion represented by formula (3D) has no fluorine atom at the α-position of the sulfonic group but has two trifluoromethyl groups at the β-position, and thus has sufficient acidity to cut off the acid-labile group in the base polymer. Therefore, it can also be used as a photoacid generator.

[0509] The photoacid generator represented by the following formula (4) is also preferably used.

[0510] [Chemistry 160]

[0511]

[0512] In formula (4), R201 and R 202 Each independently represents a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. 203 is a alkylene group having 1 to 30 carbon atoms which may contain a hetero atom. 201 , R 202 and R 203 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. In this case, a specific example of the aforementioned ring is, for example, the same as R in the description of formula (cation-1). ct1 and R ct2 The same examples are given for the rings that can be formed together with the sulfur atoms to which they are bonded.

[0513] 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, n-pentyl, tert-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; aromatic groups having 6 to 30 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl and anthracenyl; groups obtained by combinations thereof, etc. Furthermore, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0514] R 203The 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, heptane-1,17-diyl, and heptadecane-1,18-diyl. -an alkanediyl group having 1 to 30 carbon atoms, such as cyclopentanediyl, cyclohexanediyl, norbornanediyl, and adamantanediyl; a cyclic saturated alkylene group having 3 to 30 carbon atoms, such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, tert-butylnaphthylene; a group obtained by combining these groups, etc. Furthermore, part or all of the hydrogen atoms of the aforementioned alkylene group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned alkylene group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the group 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 aforementioned hetero atom is preferably an oxygen atom.

[0515] In formula (4), L A 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.

[0516] In formula (4), 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.

[0517] In formula (4), k is an integer from 0 to 3.

[0518] The photoacid generator represented by formula (4) is preferably represented by the following formula (4').

[0519] [Chemistry 161]

[0520]

[0521] In formula (4'), L A Same as above. HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 Each is independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are exemplified by the same examples. x and y are each independently an integer of 0 to 5. z is an integer of 0 to 4.

[0522] Specific examples of the photo-acid generator represented by formula (4) are the same as those exemplified for the photo-acid generator represented by formula (2) in JP-A-2017-26980.

[0523] Among the above-mentioned photoacid generators, those containing anions represented by formula (3A') or (3D) are particularly preferred because they have low acid diffusion and excellent solubility in solvents. Those represented by formula (4') are particularly preferred because they have extremely low acid diffusion.

[0524] Furthermore, as other acid generators, sulfonium salts and iodonium salts containing anions having an aromatic ring substituted with an iodine atom represented by the following formula (5-1) or (5-2) can also be used.

[0525] [Chemistry 162]

[0526]

[0527] In formula (5-1) and (5-2), p is 1, 2 or 3. q and r are integers satisfying 1≤q≤5, 0≤r≤3 and 1≤q+r≤5. q is preferably 1, 2 or 3, more preferably 2 or 3. r is preferably 0, 1 or 2.

[0528] In formula (5-1) and (5-2), L 1 It is a saturated alkylene group having 1 to 6 carbon atoms which may contain a single bond, an ether bond or an ester bond. The saturated alkylene group may be linear, branched or cyclic.

[0529] In formula (5-1) and (5-2), L 2When p is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms. When p is 2 or 3, it is a (p+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.

[0530] In formula (5-1) and (5-2), R 401 is a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbonoxy group having 1 to 20 carbon atoms, a hydrocarboncarbonyl group having 2 to 20 carbon atoms, a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms or a hydrocarbonsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group or an ether bond, or -N(R 401A )(R 401B )、-N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-OR 401D . R 401A and R 401B Each R is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. 401C 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. 401D It is an aliphatic hydrocarbon group having 1 to 16 carbon atoms, an aryl group having 6 to 14 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 p and / or r are 2 or more, each R 401 They may be the same as or different from each other.

[0531] Among these, R 401 Hydroxyl, -N(R 401C )-C(=O)-R 401D 、-N(R 401C )-C(=O)-OR 401D , fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group and the like are preferred.

[0532] In formula (5-1) and (5-2), 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 12They can also be combined to form a carbonyl group. 13 and Rf 14 All of them are preferably fluorine atoms.

[0533] In formula (5-1) and (5-2), R 402 ~R 406 Each is independently a halogen 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 described in the formula (cation-1) and (cation-2). ct1 ~R ct5 The hydrocarbon groups represented by are the same examples. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon groups may be substituted by hydroxyl groups, carboxyl groups, halogen atoms, cyano groups, nitro groups, mercapto groups, sultone rings, sulfonyl groups or groups containing sulfonium salts, and part of -CH2- of the aforementioned hydrocarbon groups may be substituted by ether bonds, ester bonds, carbonyl groups, amide bonds, carbonate bonds or sulfonate bonds. In addition, R 402 and R 403 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, specific examples of the aforementioned ring are as described in Formula (cation-1). ct1 and R ct2 The same examples are exemplified for the rings that can be formed together with the sulfur atoms to which they are bonded.

[0534] Specific examples of the cation of the sulfonium salt represented by formula (5-1) 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 (5-2) are the same as those exemplified for the iodonium cation represented by formula (cation-2).

[0535] Specific examples of the anion of the onium salt represented by the formula (5-1) or (5-2) include the following, but are not limited to these.

[0536] [Chemistry 163]

[0537]

[0538] [Chemistry 164]

[0539]

[0540] [Chemistry 165]

[0541]

[0542] [Chemistry 166]

[0543]

[0544] [Chemistry 167]

[0545]

[0546] [Chemistry 168]

[0547]

[0548] [Chemistry 169]

[0549]

[0550] [Chemistry 170]

[0551]

[0552] [Chemistry 171]

[0553]

[0554] [Chemistry 172]

[0555]

[0556] [Chemistry 173]

[0557]

[0558] [Chemistry 174]

[0559]

[0560] [Chemistry 175]

[0561]

[0562] [Chemistry 176]

[0563]

[0564] [Chemistry 177]

[0565]

[0566] [Chemistry 178]

[0567]

[0568] [Chemistry 179]

[0569]

[0570] [Chemistry 180]

[0571]

[0572] [Chemistry 181]

[0573]

[0574] [Chemistry 182]

[0575]

[0576] [Chemistry 183]

[0577]

[0578] [Chemistry 184]

[0579]

[0580] When the chemically amplified resist composition of the present invention contains an acid generator (D), the content thereof is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass, relative to 80 parts by mass of the base polymer (A). If the amount of the acid generator of the component (D) added is within the above range, resolution is good, and there is no concern of foreign matter generation after the resist film is developed or peeled off, so it is preferable. The acid generator (D) may be used alone or in combination of two or more.

[0581] [(E) Surfactant]

[0582] The chemically amplified resist composition of the present invention may further 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.

[0583] Among the surfactants described in the aforementioned bulletin, FC-4430 (manufactured by 3M Co., Ltd.), 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) are preferred as surfactants that are insoluble or poorly soluble in water and alkaline developer.

[0584] [Chemistry 185]

[0585]

[0586] Here, R, Rf, A, B, C, m, and n are not limited to the above descriptions and are applicable only to formula (surf-1). R is a 2- to 4-valent aliphatic group with 2 to 5 carbon atoms. The above-mentioned aliphatic group, for example, ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentylene, etc., for 2-valent, and for example, the following for 3- or 4-valent.

[0587] [Chemistry 186]

[0588]

[0589] In the formula, chain lines are atomic bonds, and each is a partial structure derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0590] Among these, 1,4-butylene group, 2,2-dimethyl-1,3-propylene group and the like are preferred.

[0591] 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, which is an integer of 2 to 4. A is 1. B is an integer of 2 to 25, preferably an integer of 4 to 20. C is an integer of 0 to 10, preferably 0 or 1. 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.

[0592] A surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer has the effect of reducing water penetration and leaching by aligning on the surface of the resist film when ArF immersion lithography does not use a resist protective film. Therefore, it is useful because it inhibits the dissolution of water-soluble components from the resist film and reduces damage to the exposure device. In addition, it becomes soluble 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, so it is useful. Such a surfactant is a polymer-type surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer, also known as a hydrophobic resin, and is particularly preferred because it has high water repellency and improves water sliding properties.

[0593] Specific examples of such polymeric surfactants include those containing at least one type of repeating units selected from the group consisting of repeating units represented by the following formulae (6A) to (6E).

[0594] [Chemistry 187]

[0595]

[0596] In formulas (6A) to (6E), R BW is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 It is -CH2-, -CH2CH2-, -O- or two -H separated from each other. s1 Each R is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. s2 is a single bond, or a linear or branched alkylene group having 1 to 5 carbon atoms. s3 Each R is independently a hydrogen atom, a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group. s3 When it is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between the carbon-carbon bonds. s4 is a (u+1)-valent hydrocarbon group or a fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer of 1 to 3. s5 are 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.

[0597] R s1 The hydrocarbon group having 1 to 10 carbon atoms represented by is preferably a saturated hydrocarbon group, and any of the straight chain, branched, and cyclic types may be used. 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.

[0598] R s2 The alkylene group represented by is preferably a saturated alkylene group, and may be any of a linear, branched, or cyclic type. Specific examples thereof include methylene, ethylene, propylene, butylene, and pentylene.

[0599] R s3 or R s6 The hydrocarbon group represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include saturated hydrocarbon groups, alkenyl groups, alkynyl groups, and other aliphatic unsaturated hydrocarbon groups, but saturated hydrocarbon groups are preferred. Specific examples of the aforementioned saturated hydrocarbon groups include R s1 Examples of the hydrocarbon group represented by include undecyl, dodecanyl, tridecanyl, tetradecyl, pentadecyl and the like. s3 or R s6 Specific examples of the fluorinated hydrocarbon groups represented by are groups in which a part or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon groups are replaced by fluorine atoms. As mentioned above, an ether bond or a carbonyl group may be inserted between these carbon-carbon bonds.

[0600] R s3 Specific examples of the acid-labile group represented by include groups represented by the above formulae (AL-3) to (AL-5), trialkylsilyl groups in which each alkyl group is an alkyl group having 1 to 6 carbon atoms, and alkyl groups having an oxo group having 4 to 20 carbon atoms.

[0601] R s4 The (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group represented by 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.

[0602] R sa The fluorinated hydrocarbon group represented is preferably saturated, and any of the straight chain, branched, and cyclic types are acceptable. Specific examples thereof include those in which some or all of the hydrogen atoms of the aforementioned hydrocarbon groups are substituted with fluorine atoms, specifically, for example, 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.

[0603] Specific examples of the repeating unit represented by any one of formulae (6A) to (6E) include the following, but are not limited thereto. B Same as above.

[0604] [Chemistry 188]

[0605]

[0606] [Chemistry 189]

[0607]

[0608] [Chemistry 190]

[0609]

[0610] [Chemistry 191]

[0611]

[0612] [Chemistry 192]

[0613]

[0614] The aforementioned polymeric surfactant may further contain other repeating units other than the repeating units represented by formulas (6A) to (6E). Specific examples of other repeating units include repeating units obtained from methacrylic acid, α-trifluoromethylacrylic acid derivatives, etc. In the polymeric surfactant, the content of the repeating units represented by formulas (6A) to (6E) is preferably 20 mol% or more of all the repeating units, more preferably 60 mol% or more, and more preferably 100 mol%.

[0615] 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.

[0616] A method for synthesizing the aforementioned polymer surfactant is, for example, a method in which a repeating unit represented by formula (6A) to (6E) and a monomer containing an unsaturated bond which optionally provides other repeating units are placed in an organic solvent, a free radical initiator is added, and the mixture is heated to polymerize the monomer. Specific examples of the organic solvent used in the polymerization include toluene, benzene, THF, diethyl ether, dioxane, etc. Specific examples of the polymerization initiator include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylpropionic acid) dimethyl ester, benzoyl peroxide, lauroyl peroxide, etc. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. The acid-labile group can be used directly to be introduced into the monomer, or it can be protected or partially protected after polymerization.

[0617] 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.

[0618] When the chemically amplified resist composition of the present invention contains (E) surfactant, its content is preferably 0.1 to 50 parts by mass, and more preferably 0.5 to 10 parts by mass relative to 80 parts by mass of the (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 will be sufficiently improved, and if it is 50 parts by mass or less, the dissolution rate of the resist film surface to the developer is low, and the height of the formed fine pattern can be fully maintained. (E) Surfactants can be used alone or in combination of two or more.

[0619] [(F) Dissolution inhibitor]

[0620] The chemically amplified resist composition of the present invention may further contain a dissolution inhibitor as component (F). When the chemically amplified resist composition of the present invention is positive type, by adding a dissolution inhibitor, the difference in dissolution rate between the exposed area and the unexposed area can be further increased, thereby further improving the resolution.

[0621] Specific examples of the dissolution inhibitor include, for example, a compound having a molecular weight of preferably 100 to 1000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule, wherein the hydrogen atoms of the phenolic hydroxyl groups are substituted by acid-labile groups at a ratio of 0 to 100 mol % overall, or a compound containing a carboxyl group in the molecule, wherein the hydrogen atoms of the carboxyl groups are substituted by acid-labile groups at an average ratio of 50 to 100 mol % overall. Specifically, for example, compounds in which the hydrogen atoms of the hydroxyl groups and carboxyl groups of bisphenol A, phenol, phenolphthalein, cresol novolac, naphthalenecarboxylic acid, adamantanecarboxylic acid, and bile acid are substituted by acid-labile groups, and the like, for example, those described in paragraphs

[0155] to

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

[0622] When the chemically amplified resist composition of the present invention contains (F) a dissolution inhibitor, the content thereof is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, based on 80 parts by mass of the (A) base polymer.

[0623] [(G) Other ingredients]

[0624] The chemically amplified resist composition of the present invention may also contain a compound that generates acid by acid decomposition (acid multiplication compound), an organic acid derivative, a fluorine-substituted alcohol, a water repellency enhancer, etc. as (G) other components. The aforementioned acid multiplication compound can refer to the compounds described in Japanese Patent Publication No. 2009-269953 or Japanese Patent Publication No. 2010-215608. When the aforementioned acid multiplication compound is contained, its content is preferably 0 to 5 parts by weight relative to 80 parts by weight of the (A) base polymer, and 0 to 3 parts by weight is more ideal. If the content is too much, it is difficult to control the diffusion of the acid, and sometimes the resolution and pattern shape may be degraded. The aforementioned organic acid derivative and fluorine-substituted alcohol can refer to the compounds described in Japanese Patent Publication No. 2009-269953 or Japanese Patent Publication No. 2010-215608.

[0625] The aforementioned water repellency enhancer can be used in immersion lithography without top coating. The aforementioned water repellency enhancer is preferably a polymer containing a fluorinated alkyl group, a polymer containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue of a specific structure, and the examples shown in Japanese Patent Publication No. 2007-297590 and Japanese Patent Publication No. 2008-111103 are more ideal. The aforementioned water repellency enhancer needs to be dissolved in an alkaline developer or an organic solvent developer. The aforementioned specific water repellency enhancer having a 1,1,1,3,3,3-hexafluoro-2-propanol residue has good solubility in the developer. As for the water repellency enhancer, a polymer containing a repeating unit containing an amino group or an amine salt has a high effect of preventing the acid in the PEB from evaporating and preventing poor opening of the hole pattern after development. When the chemically amplified resist composition of the present invention contains the water repellency enhancer, the content thereof is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, based on 80 parts by mass of the base polymer (A).

[0626] [Pattern Formation Method]

[0627] When the chemically amplified resist composition of the present invention is used in the manufacture of various integrated circuits, known photolithography techniques can be used. For example, a pattern forming method, for example, a method comprising the following steps: using the chemically amplified resist composition to form a resist film on a substrate, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0628] First, the chemically amplified resist composition of the present invention is coated on a substrate (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) for integrated circuit manufacturing or a substrate (Cr, CrO, CrON, MoSi2, SiO2, etc.) for mask circuit manufacturing by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or blade coating, so that the coating film thickness becomes 0.01 to 2.0 μm. It is pre-baked on a hot plate, preferably at 60 to 150° C. for 10 seconds to 30 minutes, more preferably at 80 to 120° C. for 30 seconds to 20 minutes, to form a resist film.

[0629] Next, the resist film is exposed to high-energy radiation. The high-energy radiation is, for example, ultraviolet radiation, far ultraviolet radiation, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer lasers, gamma rays, synchrotron radiation, etc. When ultraviolet radiation, far ultraviolet radiation, EUV, X-rays, soft X-rays, excimer lasers, gamma rays, synchrotron radiation, etc. are used, the exposure is preferably about 1 to 200 mJ / cm2 directly or through a mask for forming a target pattern. 2 , more preferably about 10 to 100 mJ / cm 2When EB is used as the high energy ray, the exposure is preferably about 0.1 to 100 μC / cm2, either directly or by using a mask to form a target pattern. 2 , preferably about 0.5 to 50 μC / cm 2 The chemically amplified resist composition of the present invention is particularly suitable for fine patterning using high-energy radiation such as ArF excimer laser with a wavelength of 193 nm, KrF excimer laser with a wavelength of 248 nm, EB, or EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, gamma rays, or synchrotron radiation.

[0630] After the exposure, PEB may be performed on a hot plate, preferably at 60 to 150° C. for 10 seconds to 30 minutes, more preferably at 80 to 120° C. for 30 seconds to 20 minutes.

[0631] After exposure or PEB, a developer containing 0.1 to 10% by mass, preferably 2 to 5% by mass, of an alkaline aqueous solution of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide or the like is used, and development is performed using conventional methods such as dipping, puddle, and spraying for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes. The exposed portion dissolves in the developer, while the unexposed portion does not dissolve, and a desired positive pattern can be formed on the substrate.

[0632] Instead of using the aforementioned aqueous alkali solution, an organic solvent developer may be used to obtain a negative pattern. Specific examples of the developer used in this case include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, and crotonic acid. ethyl ester, 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, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0633] At the end of the development, rinsing may be performed. The rinsing liquid is preferably a solvent that is miscible with the developer and does not dissolve the resist film. Such solvents are preferably alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms.

[0634] Specific examples of the alcohol having 3 to 10 carbon atoms include n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentanol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol.

[0635] Specific examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, and di-n-hexyl ether.

[0636] Specific examples of the aforementioned alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Specific examples of the aforementioned alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Specific examples of the aforementioned alkynes having 6 to 12 carbon atoms include hexyne, heptyne, octyne, etc.

[0637] Specific examples of the aromatic solvent include toluene, xylene, ethylbenzene, cumene, tert-butylbenzene, mesitylene, and the like.

[0638] By performing rinsing, the occurrence of resist pattern collapse and defects can be reduced. In addition, rinsing is not necessary, and by not performing rinsing, the amount of solvent used can be reduced.

[0639] The developed hole pattern and trench pattern can be shrunk by using heat flow, RELACS technology or DSA technology. A shrinking agent is coated on the hole pattern, and the shrinking agent is cross-linked on the surface of the resist film by diffusion of the acid catalyst from the resist film during baking, and the shrinking agent is attached to the side wall of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, so that the excess shrinking agent is removed and the hole pattern is shrunk.

[0640] Example

[0641] The present invention is specifically described below with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples. The apparatus used is as follows.

[0642] ·MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0643] [1] Synthesis of onium salt monomers

[0644] [Example 1-1] Synthesis of Onium Salt Monomer a-1

[0645] [Chemistry 193]

[0646]

[0647] (1) Synthesis of intermediate In-1

[0648] Under nitrogen environment, raw materials SM-1 (37.2 g), triethylamine (18.0 g) and 4-dimethylaminopyridine (1.50 g) are dissolved or suspended in THF (200 g) in a reaction container and cooled with an ice bath. Then, a solution of p-styrenesulfonyl chloride (16.4 g) dissolved in THF (50 g) is added dropwise. After the addition, the temperature in the reaction container is raised to 50°C and matured for 6 hours. Then, the reaction solution is cooled, saturated sodium bicarbonate water (100 g) is added and the reaction is stopped. The target product is extracted twice with ethyl acetate (200 g), and a usual aqueous work-up is performed. After the solvent is distilled off, it is purified by silica gel chromatography to obtain 45.8 g of the intermediate In-1 as an oil (yield 97%).

[0649] (2) Synthesis of intermediate In-2

[0650] Under nitrogen environment, the intermediate In-1 (45.8g) was dissolved in THF (200g). While cooling in an ice bath, a 25% sodium hydroxide aqueous solution (15.5g) was added dropwise. After the addition, the temperature in the reaction vessel was raised to 30°C and ripened for 12 hours. After ripening, the reaction solution was cooled, and 20% hydrochloric acid (18.2g) was added dropwise to stop the reaction. The target product was extracted twice with ethyl acetate (200g), and the usual aqueous work-up was performed. After the solvent was distilled off, it was recrystallized with hexane to obtain 37.5g of white crystalline intermediate In-2 (yield 90%).

[0651] (3) Synthesis of intermediate In-3

[0652] Under nitrogen environment, add intermediate In-2 (37.5g), raw material SM-2 (34.8g), 4-dimethylaminopyridine (1.1g) and dichloromethane (150g) to the reaction vessel and cool with an ice bath. While maintaining the temperature in the reaction vessel below 20°C, add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (20.1g) directly in a powder state. After addition, warm to room temperature and mature for 12 hours. After maturation, add water (100g) to stop the reaction, perform usual aqueous work-up, distill off the solvent, add diisopropyl ether and recrystallize to obtain 61.5g of oily intermediate In-3 (yield 89%).

[0653] (4) Synthesis of Onium Salt Monomer a-1

[0654] In a nitrogen atmosphere, the intermediate In-3 (61.5 g), the raw material SM-3 (31.8 g), dichloromethane (200 g) and water (150 g) were added to the reaction vessel, stirred for 30 minutes, and the organic layer was separated, washed with water, and then concentrated under reduced pressure. The concentrate was purified by silica gel chromatography to obtain 61.0 g of the target onium salt monomer a-1 as an oil (yield 87%).

[0655] MALDI TOF-MS: POSITIVE M + 261 (equivalent to C 18 H 13 S + )

[0656] NEGATIVE M - 766 (equivalent to C 18 H 10 F5I2O8S2 - )

[0657] [Examples 1-2 to 1-7] Synthesis of Onium Salt Monomers a-2 to a-10

[0658] Onium salt-type monomers a-2 to a-10 represented by the following formulae are synthesized using corresponding raw materials and known organic synthesis reactions.

[0659] [Chemistry 194]

[0660]

[0661] [Chemistry 195]

[0662]

[0663] [Comparative Examples 1-1 to 1-4] Comparative Synthesis of Onium Salt Monomers ca-1 to ca-4

[0664] Comparative onium salt-type monomers ca-1 to ca-4 represented by the following formulae were synthesized using corresponding raw materials and known organic synthesis reactions.

[0665] [Chemistry 196]

[0666]

[0667] [2] Synthesis of base polymer

[0668] Among the monomers used for synthesis of the base polymer, those other than the monomers a-1 to a-10 and the comparative monomers ca-1 to ca-4 are as follows.

[0669] [Chemistry 197]

[0670]

[0671] [Chemistry 198]

[0672]

[0673] [Chemistry 199]

[0674]

[0675] [Example 2-1] Synthesis of polymer P-1

[0676] Under nitrogen atmosphere, monomer a-1 (49.4 g), monomer b1-1 (39.3 g), monomer c-1 (11.5 g), 3.68 g of V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 139 g of MEK were weighed in a flask to prepare a monomer-polymerization initiator solution. MEK46 g was weighed in 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 3000 g of vigorously stirred hexane, and the precipitated polymer was filtered. The obtained polymer was washed twice with 600 g of hexane, and then vacuum dried at 50°C for 20 hours to obtain polymer P-1 in the form of white powder (yield 97.1 g, yield 97%). The Mw of polymer P-1 was 9400 and the Mw / Mn was 1.75. Mw is a polystyrene-equivalent measurement value obtained by GPC using DMF as a solvent.

[0677] [Chemistry 200]

[0678]

[0679] [Examples 2-2 to 2-23, Comparative Examples 2-1 to 2-10] Synthesis of Polymers P-2 to P-23, Comparative Polymers CP-1 to CP-10

[0680] The polymers shown in Tables 1 and 2 were produced in the same manner as in Synthesis Example 2-1 except that the types and blending ratios of the monomers were changed.

[0681] [Table 1]

[0682]

[0683] [Table 2]

[0684]

[0685] [3] Preparation of chemically amplified resist compositions

[0686] [Examples 3-1 to 3-26, Comparative Examples 3-1 to 3-10]

[0687] Predetermined components selected from the base polymers (P-1 to P-23) of the present invention, the base polymers for comparison (CP-1 to CP-10), the acid generators (PAG-1, PAG-2) and the quenchers (SQ-1 to SQ-3, AQ-1) were dissolved in a solvent containing 0.01 mass % of FC-4430 manufactured by 3M Company as a surfactant 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) type filter to prepare chemically amplified resist compositions (R-1 to R-26, CR-1 to CR-10).

[0688] [Table 3]

[0689]

[0690]

[0691] [Table 4]

[0692]

[0693] In Tables 3 and 4, the solvent, quencher (SQ-1 to SQ-4, AQ-1) and acid generator (PAG-1, PAG-2) are as follows.

[0694] Solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0695] DAA (Diacetone Alcohol)

[0696] Quenching agent: SQ-1~SQ-4, AQ-1

[0697] [Chemistry 201]

[0698]

[0699] Acid generator: PAG-1, PAG-2

[0700] [Chemistry 202]

[0701]

[0702] [4]EUV lithography evaluation (1)

[0703] [Examples 4-1 to 4-26, Comparative Examples 4-1 to 4-10]

[0704] Each chemically amplified resist composition (R-1 to R-26, CR-1 to CR-10) 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. The resist film was exposed to light using an EUV scanning exposure machine NXE3300 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, dipole illumination) while changing the exposure dose and focus (exposure dose 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.

[0705] The LS pattern was observed by Hitachi Advanced Technologies Co., Ltd.'s CG6300 SEM, and the sensitivity, EL, LWR, DOF, and collapse limit were evaluated by the following methods. The results are shown in Tables 5 and 6.

[0706] [Sensitivity evaluation]

[0707] Find the optimal exposure Eop (mJ / cm2) for obtaining a LS pattern with a line width of 18 nm and a pitch of 36 nm. 2 ), which is defined as sensitivity. The smaller this value is, the higher the sensitivity is.

[0708] [EL evaluation]

[0709] From the exposure amount formed in the range of ±10% (16.2 to 19.8 nm) of the pitch width of 18 nm in the above LS pattern, EL (unit: %) is calculated by the following formula. The larger this value is, the better the performance is.

[0710] EL(%)=(|E1-E2| / Eop)×100

[0711] E1: Optimal exposure for LS pattern with line width of 16.2nm and pitch of 36nm

[0712] E2: Optimal exposure for LS pattern with line width of 19.8nm and pitch of 36nm

[0713] Eop: Optimal exposure for LS pattern with line width of 18nm and pitch of 36nm

[0714] [LWR evaluation]

[0715] For the LS pattern obtained by Eop irradiation, the dimension of 10 points in the longitudinal direction of the line was measured, and the value (3σ) tripled by the standard deviation (σ) was calculated as LWR. The smaller this value is, the smaller the roughness is and the uniform line width pattern is obtained.

[0716] [DOF evaluation]

[0717] For focal depth evaluation, the focal range formed by the LS pattern in the range of ±10% (16.2 to 19.8 nm) of the size of 18 nm was determined. The larger this value, the wider the focal depth.

[0718] [Evaluation of Collapse Limit of Line Pattern]

[0719] 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.

[0720] [Table 5]

[0721]

[0722] [Table 6]

[0723]

[0724] From the results shown in Tables 5 and 6, it can be seen that the chemically amplified resist composition using the base polymer containing the repeating unit derived from the onium salt-type monomer 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, it is shown that the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[0725] [5]EUV lithography evaluation (2)

[0726] [Examples 5-1 to 5-26, Comparative Examples 5-1 to 5-10]

[0727] Each chemically amplified resist composition (R-1 to R-26, CR-1 to CR-10) 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 +20% deviation 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.

[0728] Using a Hitachi Advanced Technologies Co., Ltd. length measurement SEM (CG6300), the exposure amount when the hole size was formed at 23 nm was measured, and the sensitivity was defined. In addition, the hole sizes of 50 holes at this time were measured, and the value (3σ) three times the standard deviation (σ) was calculated from the results, and the size variation (CDU) was defined. The results are shown in Tables 7 and 8.

[0729] [Table 7]

[0730]

[0731] [Table 8]

[0732]

[0733] 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.

[0734] [6] Dry etching resistance evaluation

[0735] [Examples 6-1 to 6-23, Comparative Examples 6-1 to 6-10]

[0736] 2 g of each polymer shown in Tables 1 and 2 (polymers P-1 to P-23, comparative polymers CP-1 to CP-10) was dissolved in 10 g of cyclohexanone, and the polymer solution was filtered with a 0.2 μm filter. The polymer solution was spin-coated on a Si substrate to form a film with a thickness of 300 nm and evaluated under the following conditions.

[0737] Etching test using CHF3 / CF4 gas:

[0738] Using a dry etching apparatus TE-8500P manufactured by Tokyo Electron Co., Ltd., the difference in film thickness of the polymer film before and after etching was determined.

[0739] The etching conditions are as follows.

[0740]

[0741]

[0742] In this evaluation, a smaller film thickness difference, that is, a smaller reduction amount, indicates a higher etching resistance. The results of dry etching resistance are shown in Tables 9 and 10.

[0743] [Table 9]

[0744] polymer <![CDATA[Etching rate of CHF3 / CF4-based gas (nm / min)]]> Example 6-1 P-1 95 Example 6-2 P-2 96 Example 6-3 P-3 97 Example 6-4 P-4 95 Example 6-5 P-5 96 Example 6-6 P-6 96 Embodiment 6-7 P-7 97 Embodiment 6-8 P-8 95 Embodiment 6-9 P-9 94 Examples 6-10 P-10 95 Embodiment 6-11 P-11 97 Examples 6-12 P-12 96 Embodiment 6-13 P-13 95 Embodiment 6-14 P-14 98 Embodiment 6-15 P-15 96 Embodiment 6-16 P-16 95 Example 6-17 P-17 96 Example 6-18 P-18 96 Example 6-19 P-19 95 Example 6-20 P-20 96 Example 6-21 P-21 94 Example 6-22 P-22 95 Example 6-23 P-23 95

[0745] [Table 10]

[0746] polymer <![CDATA[Etching rate of CHF3 / CF4-based gas (nm / min)]]> Comparative Example 6-1 CP-1 114 Comparative Example 6-2 CP-2 118 Comparative Example 6-3 CP-3 101 Comparative Example 6-4 CP-4 100 Comparative Example 6-5 CP-5 112 Comparative Example 6-6 CP-6 115 Comparative Examples 6-7 CP-7 102 Comparative Examples 6-8 CP-8 100 Comparative Examples 6-9 CP-9 115 Comparative Examples 6-10 CP-10 103

[0747] From the results shown in Tables 9 and 10, it was confirmed that the polymer of the present invention has excellent dry etching resistance to CHF3 / CF4 system gas.

Claims

1. An onium salt type monomer represented by the following formula (a), In the formula, n1 is 0 or 1, n2 is 0 or 1, n3 is an integer of 0 to 4, n4 is an integer of 0 to 4, n5 is an integer of 1 to 6, but when n2 is 0, 1≤n4+n5≤4, when n2 is 1, 1≤n4+n5≤6, and n6 is an integer of 0 to 4, R A is 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, and when n3 is 2, 3 or 4, a plurality of R 1 They can also bond to each other and to the carbon atoms to which they are bonded to form rings. R 2 is a halogen atom other than an iodine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when n4 is 2, 3 or 4, a plurality of R 2 They can also bond to each other and to the carbon atoms to which they are bonded to form rings. L A , L B and L C are each independently a single bond, an ether bond, an ester bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond, X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom, Q 1 and Q 2 are each independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, Q 3 and Q 4 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, Z + It is an onium cation.

2. The onium salt type monomer according to claim 1, represented by the following formula (a1), In the formula, n1~n6, R A , R 1 , R 2 , L A , L C , Q 1 ~Q 4 and Z + Same as above.

3. The onium salt type monomer according to claim 2, represented by the following formula (a2), In the formula, n1~n6, R A , R 1 , R 2 , L A , Q 1 , Q 2 and Z + Same as above.

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

6. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (b1) or (b2), In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, 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, AL 1 and AL 2 are each independently an acid-labile group, 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, a is an integer from 0 to 4.

7. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (c1): In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * represents an atomic bond with a carbon atom of the main chain, R 21 is a halogen atom, a nitro group, 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, c is an integer from 1 to 4, d is an integer from 0 to 3, but 1≤c+d≤5.

8. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (d1): In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, Z 1 is a single bond, phenylene, naphthylene, *-C(=O)-OZ 11 - or *-C(=O)-NH-Z 11 -, or the phenylene 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, * represents an atomic bond to a carbon atom of the main chain, Z 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, R 31 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)-).

9. A chemically amplified resist composition comprising (A) a base polymer comprising the polymer according to claim 5. 10 . The chemically amplified resist composition according to claim 9 , further comprising (B) an organic solvent.

11. The chemically amplified resist composition according to claim 9, further comprising (C) a quencher. 12 . The chemically amplified resist composition according to claim 9 , further comprising (D) an acid generator.

13. The chemically amplified resist composition according to claim 9, further comprising (E) a surfactant.

14. The chemically amplified resist composition according to claim 9, further comprising (F) a dissolution inhibitor.

15. A pattern forming method comprising the following steps: forming a resist film on a substrate using the chemically amplified resist composition according to claim 9, exposing the resist film to high energy radiation, and The exposed resist film is developed using a developer. 16 . The pattern forming method according to claim 15 , wherein the high-energy ray is an ArF excimer laser with a wavelength of 193 nm, a KrF excimer laser with a wavelength of 248 nm, an electron beam, or an extreme ultraviolet ray with a wavelength of 3 to 15 nm.

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