Onium salt, chemically amplified resist composition and pattern forming method

Abstract

The invention relates to an onium salt, a chemically amplified resist composition and a pattern forming method. The present invention addresses the problem of providing a novel onium salt, a chemically amplified resist composition, and a pattern forming method, which are used in a chemically amplified resist composition that, in optical lithography using high-energy rays, has high sensitivity regardless of the positive type or the negative type, has excellent resolution, and can improve various lithography performance and suppress collapse of a resist pattern. The solution of the present invention is an onium salt containing an onium cation and an aromatic carboxylic acid anion containing an iodine atom and a cyclic ether structure in a part of the structure.

Description

Technical Field

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

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern patterns is progressing rapidly. With the increasing popularity of 5G high-speed communications and artificial intelligence (AI), high-performance devices are becoming increasingly essential. Among the most advanced miniaturization technologies, mass production of 5nm node devices using extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm has already begun. Furthermore, research is underway to use EUV lithography in devices for the next-generation 3nm node and the next-generation 2nm node.

[0003] As miniaturization progresses, image blurring caused by acid diffusion becomes a problem. To ensure resolution in fine patterns larger than 45 nm, it has been proposed that controlling acid diffusion is important, in addition to improving dissolution contrast, as previously proposed (Non-Patent Document 1). However, chemically amplified resist materials enhance sensitivity and contrast through acid diffusion. Therefore, attempting to minimize acid diffusion by lowering the post-exposure bake (PEB) temperature and shortening the time can significantly reduce sensitivity and contrast.

[0004] There is a triangular trade-off between sensitivity, resolution, and edge roughness (LWR). To improve resolution, it is necessary to suppress acid diffusion, but if the acid diffusion distance is shortened, sensitivity will decrease.

[0005] Adding an acid generator that generates a bulky acid is effective in inhibiting acid diffusion. To address this, some have proposed incorporating repeating units derived from an onium salt having a polymerizable unsaturated bond into the polymer. In this case, the polymer also functions as an acid generator (polymer-bonded acid generator). Patent Document 1 proposes specific sulfonium salts and iodonium salts having a polymerizable unsaturated bond that generate sulfonic acid. Patent Document 2 proposes a sulfonium salt in which the sulfonic acid is directly bonded to the main chain.

[0006] The acid-labile groups used in (meth)acrylate polymers used in ArF resist compositions undergo a deprotection reaction using an acid generator that generates a sulfonic acid with a fluorine atom substituted at the α-position. However, this deprotection reaction does not occur with an acid generator that generates a sulfonic acid or carboxylic acid without a fluorine atom substituted at the α-position. If a sulfonium salt or iodonium salt that generates a sulfonic acid with a fluorine atom substituted at the α-position is mixed with a sulfonium salt or iodonium salt that generates a sulfonic acid without a fluorine atom substituted at the α-position, the sulfonium salt or iodonium salt that generates the sulfonic acid without a fluorine atom substituted at the α-position undergoes ion exchange with the sulfonic acid with a fluorine atom substituted at the α-position. The sulfonic acid with a fluorine atom substituted at the α-position generated by light is converted back to the sulfonium salt or iodonium salt through ion exchange, allowing the sulfonium salt or iodonium salt of the sulfonic acid or carboxylic acid without a fluorine atom substituted at the α-position to function as a quencher. A resist composition using a sulfonium salt or iodonium salt that generates a carboxylic acid as a quencher has been proposed (Patent Document 3).

[0007] Sulfonium salt-type quenchers that generate carboxylic acids have been proposed. For example, sulfonium salts of salicylic acid, β-hydroxycarboxylic acid (Patent Document 4), salicylic acid derivatives (Patent Documents 5 and 6), fluorosalicylic acid (Patent Document 7), hydroxynaphthoic acid (Patent Document 8), salicylic acid with an iodine-containing aromatic substituent (Patent Document 9), and salicylic acid with a cyclic acetal structure (Patent Document 10) have been proposed. Salicylic acid is particularly effective in inhibiting acid diffusion due to intramolecular hydrogen bonding between the carboxyl and hydroxyl groups.

[0008] It has been criticized that the dimensional uniformity (CDU) of the resist pattern is reduced due to the aggregation of the quencher. It is expected that preventing the aggregation of the quencher in the resist film and making the distribution uniform will improve the dimensional uniformity of the pattern after development.

[0009] The demand for further miniaturization has led to challenges, particularly in alkaline development of positive resists, such as swelling caused by the developer and pattern collapse during fine pattern formation. To address these miniaturization challenges, the development of novel materials for resist compositions is crucial. The development of onium salt-based quenchers that offer excellent sensitivity, well-controlled acid diffusion, excellent solvent solubility, and are effective in suppressing pattern collapse is highly anticipated.

[0010] Prior art literature

[0011] Patent Literature

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-45311

[0013] [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-178317

[0014] [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-114431

[0015] [Patent Document 4] International Publication No. 2018 / 159560

[0016] [Patent Document 5] Japanese Patent Application Laid-Open No. 2020-203984

[0017] [Patent Document 6] Japanese Patent Application Laid-Open No. 2020-91404

[0018] [Patent Document 7] Japanese Patent Application Laid-Open No. 2020-91312

[0019] [Patent Document 8] Japanese Patent Application Laid-Open No. 2019-120760

[0020] [Patent Document 9] Japanese Patent Application Laid-Open No. 2022-77505

[0021] [Patent Document 10] International Publication No. 2023 / 189502

[0022] Non-patent literature

[0023] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) Summary of the Invention

[0024] [Problems to be Solved by the Invention]

[0025] In response to recent demands for high-resolution resist patterns, conventional resist compositions using sulfonium salt-type acid generators and quenchers have been unable to adequately suppress acid diffusion, resulting in degradation of lithographic performance, including contrast, exposure margin (EL), LWR, CDU, and depth of focus (DOF). Furthermore, these compositions can cause pattern collapse due to swelling during fine pattern formation.

[0026] The present invention has been made in view of the above-mentioned circumstances, and its object is to provide a novel onium salt for use in a chemically amplified resist composition, a chemically amplified resist composition, and a pattern forming method that have high sensitivity and excellent resolution in both positive and negative working modes, can improve lithography performance such as EL, LWR, CDU, and DOF, and can suppress the collapse of the resist pattern in optical lithography using high-energy radiation such as extreme ultraviolet rays, electron beams (EB), and EUV.

[0027] [Methods for solving the problem]

[0028] The inventors of the present application have conducted intensive research to achieve the aforementioned objectives and have discovered that an onium salt comprising an aromatic carboxylate anion and an onium cation having an iodine atom and a cyclic ether structure in a partial structure has excellent solvent solubility. A chemically amplified resist composition using this salt as a quencher exhibits high sensitivity and high contrast, as well as excellent lithographic properties such as EL, LWR, CDU, and DOF. This salt is extremely effective in suppressing pattern collapse during fine pattern formation, leading to the completion of the present invention.

[0029] That is, the present invention provides the following onium salt, chemically amplified resist composition, and pattern forming method.

[0030] An onium salt comprising an aromatic carboxylic acid anion having an iodine atom and a cyclic ether structure in a partial structure and an onium cation.

[0031] 2. The onium salt according to 1 is represented by the following formula (1).

[0032] [Chemistry 1]

[0033]

[0034] Wherein, n1 is 0 or 1; n2 is an integer from 1 to 4; n3 is an integer from 1 to 4; n4 is an integer from 0 to 3; but when n1 is 0, 2≤n2+n3+n4≤5, and when n1 is 1, 2≤n2+n3+n4≤7;

[0035] W A is a group containing a cyclic ether structure having 2 to 10 carbon atoms;

[0036] R 1 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. 1 They may also be bonded to each other and to form a ring together with the carbon atoms on the aromatic ring to which they are bonded, and a portion of the -CH2- of the ring may also be substituted by -O- or -S-;

[0037] L A and L B are each independently a single bond, an ether bond, a thioether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond, or a carbamate bond;

[0038] X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain heteroatoms;

[0039] Z + Onium cation.

[0040] 3. The onium salt of 2, wherein L A It is an ether bond or a thioether bond.

[0041] 4. The onium salt of 2 or 3, wherein W A It is an oxirane ring which may have a substituent, an oxetane ring which may have a substituent, a tetrahydrofuran ring which may have a substituent, or a tetrahydropyran ring which may have a substituent.

[0042] 5. The onium salt according to any one of items 2 to 4, wherein Z + It is a sulfonium cation represented by the following formula (cation-1), an iodonium cation represented by the following formula (cation-2), or an ammonium cation represented by the following formula (cation-3).

[0043] [Chemistry 2]

[0044]

[0045] Where R ct1 ~R ct9 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 ~R ct3 Any two of them may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, R ct6 ~R ct9 Any two of them may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded.

[0046] 6. A quencher consisting of the onium salt according to any one of 1 to 5.

[0047] 7. A chemically amplified resist composition comprising the quencher according to 6.

[0048] 8. The chemically amplified resist composition according to 7, comprising a base polymer containing a repeating unit represented by the following formula (a1).

[0049] [Chemistry 3]

[0050]

[0051] Where R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0052] X 1 is a single bond, phenylene, naphthylene or *-C(=O)-OX 11 -, and the phenylene or naphthylene group may be substituted by an alkoxy group having 1 to 10 carbon atoms or a halogen atom which may also contain a fluorine 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; * represents an atomic bond to a carbon atom of the main chain;

[0053] AL1 It is an acid-labile group.

[0054] 9. The chemically amplified resist composition according to 8, wherein the base polymer comprises a repeating unit represented by the following formula (a2).

[0055] [Chemistry 4]

[0056]

[0057] Where R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0058] X 2 is a single bond or *-C(=O)-O-; * represents an atomic bond to a carbon atom of the main chain;

[0059] 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;

[0060] AL 2 It is an acid-labile group;

[0061] a is an integer from 0 to 4.

[0062] 10. The chemically amplified resist composition according to 8 or 9, wherein the base polymer comprises a repeating unit represented by the following formula (b1) or (b2).

[0063] [Chemistry 5]

[0064]

[0065] Where R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0066] Y 1 is a single bond or *-C(=O)-O-; * represents an atomic bond to a carbon atom of the main chain;

[0067] R 21 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)-);

[0068] R 22is a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom;

[0069] b is an integer from 1 to 4; c is an integer from 0 to 4; but 1≤b+c≤5.

[0070] 11. The chemically amplified resist composition according to any one of 8 to 10, wherein the base polymer comprises at least one selected from the group consisting of a repeating unit represented by the following formula (c1), a repeating unit represented by the following formula (c2), a repeating unit represented by the following formula (c3), and a repeating unit represented by the following formula (c4).

[0071] [Chemistry 6]

[0072]

[0073] Where R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0074] Z 1 is a single bond or a phenylene group which may have a substituent;

[0075] Z 2 is a single bond, **-C(=O)-OZ 21 -, **-C(=O)-NH-Z 21 -or**-OZ 21 -;Z 21 An aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may also contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group;

[0076] Z 3 is a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond;

[0077] Z 4 is a single bond, an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may also contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group;

[0078] Z 5 Each independently represents a single bond, and optionally substituted phenylene, naphthylene or *-C(=O)-OZ 51 -;Z 51 is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the aliphatic alkylene group may also contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or a lactone ring;

[0079] Z 6 is a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond;

[0080] Z 7 Each is independently a single bond, ***-Z 71 -C(=O)-O-、***-C(=O)-NH-Z 71 -or***-OZ 71 -;Z 71 is an alkylene group having 1 to 20 carbon atoms which may also contain heteroatoms;

[0081] Z 8 Each is independently a single bond, ****-Z 81 -C(=O)-O-、****-C(=O)-NH-Z 81 -or ****-OZ 81 -;Z 81 is an alkylene group having 1 to 20 carbon atoms which may also contain heteroatoms;

[0082] Z 9 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 91 -, *-C(=O)-N(H)-Z 91 -or*-OZ 91 -;Z 91 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group;

[0083] * indicates the atomic bond with the carbon atom of the main chain; ** indicates the atomic bond with Z 1 *** indicates atomic bond with Z 6 **** indicates the atomic bond with Z 7 atomic bonds;

[0084] R 31 and R 32 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom; and R 31 and R 32 They may also bond to each other and form a ring together with the sulfur atom to which they are bonded;

[0085] L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond, or a carbamate bond;

[0086] Rf 1 and Rf 2Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms;

[0087] Rf 3 and Rf 4 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms;

[0088] Rf 5 and Rf 6 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; however, Rf 5 and Rf 6 They will not all be hydrogen atoms at the same time;

[0089] M - It is a non-nucleophilic relative ion;

[0090] A + is an onium cation;

[0091] d is 0, 1, 2 or 3.

[0092] 12. The chemically amplified resist composition according to any one of 7 to 11, further comprising an organic solvent.

[0093] 13. The chemically amplified resist composition according to any one of items 7 to 12, further comprising a photoacid generator that generates a strong acid.

[0094] 14. The chemically amplified resist composition according to any one of 7 to 13, further comprising a quencher other than the quencher according to 6.

[0095] 15. The chemically amplified resist composition according to any one of 7 to 14, further comprising a surfactant.

[0096] 16. A pattern forming method comprising the following steps:

[0097] forming a resist film on a substrate using the chemically amplified resist composition according to any one of items 7 to 15;

[0098] exposing the resist film to high-energy radiation; and

[0099] The exposed resist film is developed using a developer.

[0100] 17. The pattern forming method according to 16, wherein the high-energy ray is KrF excimer laser, ArF excimer laser, electron beam (EB) or EUV with a wavelength of 3 to 15 nm.

[0101] [Effects of the Invention]

[0102] When a chemically amplified resist composition containing the onium salt of the present invention as a quencher is used for pattern formation, a resist pattern having high contrast and good sensitivity and excellent lithographic properties such as EL, LWR, CDU, and DOF can be formed. DETAILED DESCRIPTION

[0103] [Onium salt]

[0104] The onium salt of the present invention is characterized by comprising an aromatic carboxylic acid anion and an onium cation having an iodine atom and a cyclic ether structure in a partial structure.

[0105] The onium salt is preferably represented by the following formula (1).

[0106] [Chemistry 7]

[0107]

[0108] In formula (1), n1 is 0 or 1. When n1 is 0, it is a benzene ring, and when n1 is 1, it is a naphthalene ring. However, from the perspective of solvent solubility, n1 is preferably a benzene ring of 0. n2 is an integer from 1 to 4. From the perspective of raw material supply, 1, 2, or 3 is more preferably, and 1 or 2 is more preferably. n3 is an integer from 1 to 4. From the perspective of raw material supply, 1, 2, or 3 is more preferably, and from the perspective of solvent solubility, 1 or 2 is more preferably. n4 is an integer from 0 to 3. However, when n1 is 0, 2≤n2+n3+n4≤5, and when n1 is 1, 2≤n2+n3+n4≤7.

[0109] In formula (1), W A A group containing a cyclic ether structure having 2 to 10 carbon atoms. The group containing a cyclic ether structure is preferably an oxirane ring which may have a substituent, an oxetane ring which may have a substituent, a tetrahydrofuran ring which may have a substituent, or a tetrahydropyran ring which may have a substituent. An oxirane ring which may have a substituent or an oxetane ring which may have a substituent is more preferred. The substituent is preferably a saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methyl group, an ethyl group, or the like.

[0110] In formula (1), R 1It is a halogen atom other than an iodine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. As for the halogen atom other than an iodine atom, fluorine atom, chlorine atom and bromine atom are mentioned, and fluorine atom is more preferable. The hydrocarbon group having 1 to 20 carbon atoms may be saturated or unsaturated, and may be linear, branched or cyclic. As specific examples thereof, alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl may be mentioned; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, norbornylmethyl, adamantyl, adamantylmethyl, tricyclo[5.2.1.0 2,6 ]Decyl, Tetracyclic [6.2.1.1 3,6 .0 2 ,7 Cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as dodecyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, pentenyl, and hexenyl; alkynyl groups having 2 to 20 carbon atoms, such as ethynyl, propynyl, butynyl, pentynyl, and hexynyl; cyclic unsaturated aliphatic hydrocarbon groups having 3 to 12 carbon atoms, such as cyclopentenyl and cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and indanyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups derived from combinations thereof. Furthermore, the aforementioned hydrocarbon groups may contain heteroatoms, specifically, halogen atoms, oxygen atoms, sulfur atoms, and the like.

[0111] Moreover, when n4 is 2 or 3, the complex number R 1 They may also be bonded to each other to form a ring together with the carbon atoms on the aromatic ring to which they are bonded, and a portion of the -CH2- of the ring may be substituted by -O- or -S-. Specific examples of the ring formed in this case include cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclooctane ring, norbornane ring, adamantane ring, tricyclic [5.2.1.0 2,6 ]Decane ring, tetracyclic [6.2.1.1 3,6 .0 2,7 ] dodecane rings, wherein a portion of -CH2- in these rings is substituted by -O- or -S-.

[0112] In formula (1), L A and L B Each independently represents a single bond, an ether bond, a thioether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond, or a carbamate bond. A As for L, it is preferably a single bond, an ether bond, a thioether bond or an ester bond, and is more preferably an ether bond or a thioether bond. BIn terms of alkyl, it is preferably a single bond, an ether bond, a thioether bond, or an ester bond, and more preferably a single bond, an ether bond, or an ester bond.

[0113] In formula (1), X L A alkylene group having 1 to 40 carbon atoms, which is a single bond or may contain heteroatoms. The alkylene group may be linear, branched, or cyclic. Specific examples thereof include alkanediyl, cyclic saturated alkylene, and arylene groups. Specific examples of the heteroatoms include oxygen, nitrogen, and sulfur atoms.

[0114] Just X L Specific examples of the alkylene group having 1 to 40 carbon atoms which may contain heteroatoms include the following, but are not limited to these. A and L B atomic bonds.

[0115] [Chemistry 8]

[0116]

[0117] [Chemistry 9]

[0118]

[0119] [Chemistry 10]

[0120]

[0121] [Chemistry 11]

[0122]

[0123] Among these, X L -0~X L -22 and X L -47~X L -58 is ideal.

[0124] Specific examples of the anion of the onium salt represented by formula (1) include those shown below, but are not limited to these.

[0125] [Chemistry 12]

[0126]

[0127] [Chemistry 13]

[0128]

[0129] [Chemistry 14]

[0130]

[0131] [Chemistry 15]

[0132]

[0133] [Chemistry 16]

[0134]

[0135] [Chemistry 17]

[0136]

[0137] [Chemistry 18]

[0138]

[0139] [Chemistry 19]

[0140]

[0141] [Chemistry 20]

[0142]

[0143] [Chemistry 21]

[0144]

[0145] [Chemistry 22]

[0146]

[0147] [Chemistry 23]

[0148]

[0149] [Chemistry 24]

[0150]

[0151] [Chemistry 25]

[0152]

[0153] [Chemistry 26]

[0154]

[0155] [Chemistry 27]

[0156]

[0157] [Chemistry 28]

[0158]

[0159] [Chemistry 29]

[0160]

[0161] [Chemistry 30]

[0162]

[0163] [Chemistry 31]

[0164]

[0165] [Chemistry 32]

[0166]

[0167] [Chemistry 33]

[0168]

[0169] [Chemistry 34]

[0170]

[0171] [Chemistry 35]

[0172]

[0173] [Chemistry 36]

[0174]

[0175] [Chemistry 37]

[0176]

[0177] [Chemistry 38]

[0178]

[0179] [Chemistry 39]

[0180]

[0181] [Chemistry 40]

[0182]

[0183] [Chemistry 41]

[0184]

[0185] [Chemistry 42]

[0186]

[0187] [Chemistry 43]

[0188]

[0189] [Chemistry 44]

[0190]

[0191] [Chemistry 45]

[0192]

[0193] [Chemistry 46]

[0194]

[0195] [Chemistry 47]

[0196]

[0197] [Chemistry 48]

[0198]

[0199] [Chemistry 49]

[0200]

[0201] [Chemistry 50]

[0202]

[0203] [Chemistry 51]

[0204]

[0205] [Chemistry 52]

[0206]

[0207] [Chemistry 53]

[0208]

[0209] [Chemistry 54]

[0210]

[0211] [Chemistry 55]

[0212]

[0213] [Chemistry 56]

[0214]

[0215] [Chemistry 57]

[0216]

[0217] [Chemistry 58]

[0218]

[0219] [Chemistry 59]

[0220]

[0221] [Chemistry 60]

[0222]

[0223] [Chemistry 61]

[0224]

[0225] [Chemistry 62]

[0226]

[0227] [Chemistry 63]

[0228]

[0229] [Chemistry 64]

[0230]

[0231] [Chemistry 65]

[0232]

[0233] [Chemistry 66]

[0234]

[0235] [Chemistry 67]

[0236]

[0237] [Chemistry 68]

[0238]

[0239] [Chemistry 69]

[0240]

[0241] [Chemistry 70]

[0242]

[0243] [Chemistry 71]

[0244]

[0245] [Chemistry 72]

[0246]

[0247] [Chemistry 73]

[0248]

[0249] [Chemistry 74]

[0250]

[0251] [Chemistry 75]

[0252]

[0253] [Chemistry 76]

[0254]

[0255] [Chemistry 77]

[0256]

[0257] [Chemistry 78]

[0258]

[0259] [Chemistry 79]

[0260]

[0261] [Chemistry 80]

[0262]

[0263] [Chemistry 81]

[0264]

[0265] [Chemistry 82]

[0266]

[0267] [Chemistry 83]

[0268]

[0269] [Chemistry 84]

[0270]

[0271] [Chemistry 85]

[0272]

[0273] [Chemistry 86]

[0274]

[0275] [Chemistry 87]

[0276]

[0277] [Chemistry 88]

[0278]

[0279] [Chemistry 89]

[0280]

[0281] [Chemistry 90]

[0282]

[0283] [Chemistry 91]

[0284]

[0285] [Chemistry 92]

[0286]

[0287] [Chemistry 93]

[0288]

[0289] [Chemistry 94]

[0290]

[0291] [Chemistry 95]

[0292]

[0293] [Chemistry 96]

[0294]

[0295] [Chemistry 97]

[0296]

[0297] [Chemistry 98]

[0298]

[0299] [Chemistry 99]

[0300]

[0301] [Chemistry 100]

[0302]

[0303] [Chemistry 101]

[0304]

[0305] [Chemistry 102]

[0306]

[0307] [Chemistry 103]

[0308]

[0309] [Chemistry 104]

[0310]

[0311] [Chemistry 105]

[0312]

[0313] [Chemistry 106]

[0314]

[0315] [Chemistry 107]

[0316]

[0317] [Chemistry 108]

[0318]

[0319] In formula (1), Z + The onium cation is preferably a sulfonium cation represented by the following formula (cation-1), an iodonium cation represented by the following formula (cation-2), or an ammonium cation represented by the following formula (cation-3).

[0320] [Chemistry 109]

[0321]

[0322] In formulas (cation-1) to (cation-3), R ct1 ~R ct9 Each is independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom.

[0323] Just R ct1 ~R ct9Specific examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0324] R ct1 ~R ct9 The hydrocarbon group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples 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 combinations thereof. 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.

[0325] Again, R ct1 ~R ct3 Any two of them may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, specific examples of the structure of the ring include those represented by the following formula.

[0326] [Chemistry 110]

[0327]

[0328] In the formula, the dotted line represents the ct3 atomic bonds.

[0329] Then, R ct6 ~R ct9 Any two of them may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded.

[0330] Specific examples of the sulfonium cation represented by formula (cation-1) include those shown below, but are not limited to these.

[0331] [Chemistry 111]

[0332]

[0333] [Chemistry 112]

[0334]

[0335] [Chemistry 113]

[0336]

[0337] [Chemistry 114]

[0338]

[0339] [Chemistry 115]

[0340]

[0341] [Chemistry 116]

[0342]

[0343] [Chemistry 117]

[0344]

[0345] [Chemistry 118]

[0346]

[0347] [Chemistry 119]

[0348]

[0349] [Chemistry 120]

[0350]

[0351] [Chemistry 121]

[0352]

[0353] [Chemistry 122]

[0354]

[0355] [Chemistry 123]

[0356]

[0357] [Chemistry 124]

[0358]

[0359] [Chemistry 125]

[0360]

[0361] [Chemistry 126]

[0362]

[0363] [Chemistry 127]

[0364]

[0365] [Chemistry 128]

[0366]

[0367] [Chemistry 129]

[0368]

[0369] [Chemistry 130]

[0370]

[0371] [Chemistry 131]

[0372]

[0373] [Chemistry 132]

[0374]

[0375] [Chemistry 133]

[0376]

[0377] [Chemistry 134]

[0378]

[0379] [Chemistry 135]

[0380]

[0381] [Chemistry 136]

[0382]

[0383] [Chemistry 137]

[0384]

[0385] Specific examples of the iodonium cation represented by formula (cation-2) include those shown below, but are not limited to these.

[0386] [Chemistry 138]

[0387]

[0388] [Chemistry 139]

[0389]

[0390] Specific examples of the ammonium cation represented by formula (cation-3) include those shown below, but are not limited to these.

[0391] [Chemistry 140]

[0392]

[0393] Specific examples of the onium salt of the present invention include any combination of the aforementioned anions and cations.

[0394] The onium salt of the present invention can be synthesized by a known method. As an example, a method for producing an onium salt represented by the following formula (PDQ-1-ex) will be described.

[0395] [Chemistry 141]

[0396]

[0397] Where n1~n4, W A 、R 1 、L A 、X L and Z + Same as above. X It is a group that forms a primary or secondary ester together with the adjacent carbonyloxy group. Y is a leaving group such as a chlorine atom, a bromine atom, an iodine atom, a p-toluenesulfonyl group, a methanesulfonyl group, or a trifluoromethanesulfonyl group. - is the relative anion.

[0398] In the first step, a commercially available product or a raw material SM-1 that can be synthesized by a known synthesis method is reacted with a raw material SM-2 to obtain an intermediate In-1. The reaction can be carried out by a known organic synthesis method. Specifically, the raw material SM-1 is dissolved in an aprotic polar solvent such as acetone, acetonitrile, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), a base is added, and the raw material SM-2 is added dropwise to react. For the specific example of the base used, hydroxides such as sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, carbonates such as potassium carbonate, sodium bicarbonate, etc. can be listed. These bases can be used alone or in combination of two or more. It can also be heated as needed. With regard to the reaction temperature, it can be carried out from room temperature to the boiling point of the solvent used, but it is more ideal to carry out the reaction smoothly under heating conditions. In addition, the reaction can be accelerated by adding an alkali metal iodide as a catalyst. For its example, sodium iodide and potassium iodide can be listed. Considering the yield, the reaction time is preferably monitored by silica gel thin-layer chromatography (TLC) until completion, typically about 4 to 12 hours. The reaction is then quenched with water, the desired compound is extracted from the reaction mixture, and a standard aqueous workup is performed to obtain the intermediate In-1-ex. If necessary, the obtained intermediate In-1-ex can be purified using standard methods such as chromatography and recrystallization.

[0399] Step 2: -CO2R in the intermediate In-1-ex x The primary or secondary ester bond of Z is hydrolyzed by alkali and then reacted with + X - The step of obtaining the onium salt PDQ-1-ex by salt exchange with the onium salt represented by PDQ-1-ex. The reaction can be carried out by a known organic synthesis method. Specifically, the step of alkaline hydrolysis is to suspend the intermediate In-1-ex in an ether solvent such as water or tetrahydrofuran (THF), and add a base to carry out hydrolysis. As for the base used, an alkali metal hydroxide such as sodium hydroxide and potassium hydroxide is more ideal. As for the reaction temperature, it is carried out at room temperature to the boiling point of the solvent used. It is more ideal to carry out the reaction under heating conditions so that the reaction can proceed smoothly. The reaction time, considering the yield point, is expected to be terminated by tracking the reaction with TLC, and is usually about 4 to 12 hours. Afterwards, the hydrolysis product can be separated from the reaction solution, or it can be separated without separation and mixed with Z + X - The onium salt represented by X is subjected to salt exchange. A solvent such as dichloromethane is added to the solution after alkaline hydrolysis, and the two-layer system is stirred to carry out a salt exchange reaction. -Chloride, bromide, iodide, or methylsulfate anions are preferred because the exchange reaction proceeds easily and quantitatively. The progress of the reaction should be confirmed by TLC to assess yield. The onium salt (PDQ-1-ex) can be obtained from the reaction mixture by conventional aqueous workup. If necessary, purification can be performed using standard methods such as chromatography and recrystallization.

[0400] The above-mentioned production method is merely an example, and the production method of the onium salt of the present invention is not limited thereto.

[0401] As for the structural characteristics of the onium salt of the present invention, examples include the inclusion of iodine atoms and cyclic ether structures in the partial structure of the aromatic carboxylic acid anion. Because the iodine atom has a strong absorption of EUV at a wavelength of 13.5nm, secondary electrons are generated during exposure, and the energy transfer of the secondary electrons in the photoacid generator promotes decomposition, thereby achieving high sensitivity. Then, the iodine atom has a moderate dissolution inhibition energy, and in particular, it will suppress the pattern collapse of the unexposed part in response to alkaline developer. On the other hand, the cyclic ether structure functions as an acid diffusion inhibition group, and the hydrogen bond between the ether oxygen atom and the acid generated from the photoacid generator will suppress excessive acid diffusion. The onium salt of the present invention has a strong alkalinity because it has an aromatic carboxylic acid anion, and it will effectively capture the strong acid generated from the photoacid generator. Due to these multiplying effects, when using the onium salt of the present invention, a pattern with high dissolution contrast, excellent LWR of the line pattern, excellent CDU of the hole pattern, and strong resistance to pattern collapse can be formed, so it is suitable as a material for positive resist composition.

[0402] The onium salt of the present invention can be ideally used as a quencher. In addition, in the present invention, the so-called quencher refers to a material that can form a desired pattern by capturing the strong acid generated from the photoacid generator to prevent it from diffusing to the unexposed part. The so-called photoacid generator is a compound that generates a strong acid due to high-energy radiation irradiation, and the so-called strong acid is a compound with sufficient acidity to trigger the deprotection reaction of the acid-labile group. In the case where the acid-labile group of the aforementioned aromatic carboxylic acid is a tertiary ester or tertiary ether, since it does not have an acidity sufficient to trigger the deprotection reaction, it is effective to add a photoacid generator of a sulfonic acid, imidic acid or methylated acid that is fluorinated at the α-position and generates a strong acid, as described later. In addition, the photoacid generator that generates a sulfonic acid, imidic acid or methylated acid that is fluorinated at the α-position can be of an additive type or a polymer-bonded type bonded to the base polymer.

[0403] If the aforementioned onium salt that produces aromatic carboxylic acids is mixed with a photoacid generator that produces superacidic perfluoroalkylsulfonic acids and then irradiated with light, aromatic carboxylic acids and perfluoroalkylsulfonic acids will be produced. Not all photoacid generators decompose, so undecomposed photoacid generators may remain nearby. Here, if the onium salt that produces aromatic carboxylic acids coexists with perfluoroalkylsulfonic acids, the perfluoroalkylsulfonic acid will initially undergo ion exchange with the onium salt that produces aromatic carboxylic acids, producing the onium perfluoroalkylsulfonate salt, and the aromatic carboxylic acids will be released. This is because perfluoroalkylsulfonates, being strong acids, are relatively stable. On the other hand, even if the onium perfluoroalkylsulfonate salt and aromatic carboxylic acids are present, ion exchange does not occur. In addition to perfluoroalkylsulfonic acids, similar ion exchange also occurs with aromatic hydrocarbon sulfonic acids, alkylsulfonic acids, imidic acids, methylated acids, and the like, which have higher acid strengths than the aromatic carboxylic acids produced from the onium salts of the present invention.

[0404] [Chemically amplified resist composition]

[0405] [(A) Quencher]

[0406] The chemically amplified resist composition of the present invention contains (A) a quencher composed of an onium salt represented by formula (1) as an essential component.

[0407] In the chemically amplified resist composition of the present invention, the content of the quencher (A) is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 30 parts by mass, relative to 80 parts by mass of the base polymer described below. A content of the quencher (A) within the aforementioned range is preferred because it provides excellent sensitivity and resolution, and eliminates the risk of foreign matter generation after development or during stripping of the resist film. The quenchers (A) may be used alone or in combination of two or more.

[0408] [(B) Base polymer]

[0409] The chemically amplified resist composition of the present invention may also contain a base polymer as component (B). The base polymer (B) is a polymer containing a repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1).

[0410] [Chemistry 142]

[0411]

[0412] In formula (a1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0413] In formula (a1), X 1 is a single bond, phenylene, naphthylene or *-C(=O)-OX 11-, the phenylene group or naphthylene group may be substituted with an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom or a halogen atom. 11 It is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group. The saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. * represents an atomic bond to a carbon atom of the main chain.

[0414] In formula (a1), AL 1 Specific examples of the acid-labile group include those described in JP-A-2013-80033 and JP-A-2013-83821.

[0415] Representative examples of the acid-labile group include those represented by the following formulae (AL-1) to (AL-3).

[0416] [Chemistry 143]

[0417]

[0418] In the formula, the dotted lines represent atomic bonds.

[0419] 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, sulfur, nitrogen, and fluorine atoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbon group preferably has 1 to 20 carbon atoms.

[0420] In formula (AL-1), k is an integer of 0 to 10, preferably an integer of 1 to 5.

[0421] 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 also contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The aforementioned hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. L2 、R L3 and R L4 Any two of them may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. The above-mentioned ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0422] In formula (AL-3), R L5 、R L6 and R L7Each is independently a hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. L5 、R L6 and R L7 Any two of the above may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded. The above ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0423] Specific examples of the repeating unit a1 include those shown below, but are not limited to these. A and AL 1 Same as above.

[0424] [Chemistry 144]

[0425]

[0426] [Chemistry 145]

[0427]

[0428] [Chemistry 146]

[0429]

[0430] [Chemistry 147]

[0431]

[0432] The base polymer may further contain a repeating unit represented by the following formula (a2) (hereinafter also referred to as repeating unit a2).

[0433] [Chemistry 148]

[0434]

[0435] In formula (a2), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 2 It is a single bond or *-C(=O)-O-. * represents an atomic bond to a carbon atom of the main chain. 11 AL is a halogen atom, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom. 2 For example, the acid-labile group is an acid-labile group. 1The acid-labile groups represented by are the same as those exemplified above. a is an integer of 0 to 4, and is preferably 0 or 1.

[0436] Specific examples of the repeating unit a2 include those shown below, but are not limited to these. A and AL 2 Same as above.

[0437] [Chemistry 149]

[0438]

[0439] [Chemistry 150]

[0440]

[0441] The base polymer preferably further includes a repeating unit represented by the following formula (b1) (hereinafter also referred to as repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit b2).

[0442] [Chemistry 151]

[0443]

[0444] In formulas (b1) and (b2), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 It is a single bond or *-C(=O)-O-. * represents an atomic bond to a carbon atom of the main chain. 21 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)-). 22 The group may be a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. b is an integer from 1 to 4. c is an integer from 0 to 4. However, 1 ≤ b + c ≤ 5.

[0445] Specific examples of the repeating unit b1 include those shown below, but are not limited to these. A Same as above.

[0446] [Chemistry 152]

[0447]

[0448] [Chemistry 153]

[0449]

[0450] [Chemistry 154]

[0451]

[0452] [Chemistry 155]

[0453]

[0454] [Chemistry 156]

[0455]

[0456] [Chemistry 157]

[0457]

[0458] [Chemistry 158]

[0459]

[0460] [Chemistry 159]

[0461]

[0462] [Chemistry 160]

[0463]

[0464] [Chemistry 161]

[0465]

[0466] [Chemistry 162]

[0467]

[0468] [Chemistry 163]

[0469]

[0470] [Chemistry 164]

[0471]

[0472] [Chemistry 165]

[0473]

[0474] [Chemistry 166]

[0475]

[0476] [Chemistry 167]

[0477]

[0478] Specific examples of the repeating unit b2 include those shown below, but are not limited to these. A Same as above.

[0479] [Chemistry 168]

[0480]

[0481] [Chemistry 169]

[0482]

[0483] [Chemistry 170]

[0484]

[0485] [Chemistry 171]

[0486]

[0487] [Chemistry 172]

[0488]

[0489] As for the repeating unit b1 or b2, in ArF lithography, those having a lactone ring as a polar group are more preferred, and in KrF lithography, EB lithography, and EUV lithography, those having a phenol moiety are more preferred.

[0490] The aforementioned base polymer may further contain at least one selected from the repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit c1), the repeating unit represented by the following formula (c2) (hereinafter also referred to as repeating unit c2), the repeating unit represented by the following formula (c3) (hereinafter also referred to as repeating unit c3) and the repeating unit represented by the following formula (c4) (hereinafter also referred to as repeating unit c4).

[0491] [Chemistry 173]

[0492]

[0493] In formulas (c1) to (c4), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 is a single bond or a phenylene group which may have a substituent. 2 is a single bond, **-C(=O)-OZ 21 -、

[0494] **-C(=O)-NH-Z 21 -or**-OZ 21 -.Z 21 It is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group.

[0495] Z 3 is a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond. 4 It is a single bond, an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 5 Each independently represents a single bond, and optionally substituted phenylene, naphthylene or *-C(=O)-OZ 51 -.Z 51 Z is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may contain a halogen atom, a hydroxyl group, an ether bond, an ester bond or a lactone ring. 6 is a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond. 7 Each is independently a single bond, ***-Z 71 -C(=O)-O-,

[0496] ***-C(=O)-NH-Z 71 -or***-OZ 71 -.Z 71 It is a C1-20 alkylene group which may contain a heteroatom. 8 Each is independently a single bond, ****-Z 81 -C(=O)-O-、****-C(=O)-NH-Z 81 -or ****-OZ 81 -.Z 81 It is a C1-20 alkylene group which may contain a heteroatom. 9 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 91 -, *-C(=O)-N(H)-Z 91 -or*-OZ 91 -.Z 91 It is an aliphatic alkylene group, phenylene group, fluorinated phenylene group or phenylene group substituted with trifluoromethyl group having 1 to 6 carbon atoms, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group. * indicates an atomic bond to a carbon atom of the main chain. ** indicates an atomic bond to Z 1 *** indicates atomic bond with Z 6**** indicates the atomic bond with Z 7 atomic bonds.

[0497] Z 21 , Z 51 and Z 91 The aliphatic alkylene group represented may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups such as methane-1,1-diyl, ethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-2,2-diyl, butane-1,1-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-2,3-diyl, butane-1,4-diyl, 1,1-dimethylethane-1,2-diyl, pentane-1,5-diyl, 2-methylbutane-1,2-diyl, and hexane-1,6-diyl; cycloalkanediyl groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining these groups.

[0498] Z 71 and Z 81 The alkylene group which may contain a heteroatom may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those shown below, but are not limited to these.

[0499] [Chemistry 174]

[0500]

[0501] In the formula, the dotted lines represent atomic bonds.

[0502] In formula (c1), R 31 and R 32Each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these. Aryl groups are more preferred. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing 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 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.

[0503] Again, R 31 and R 32 They may also be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, as specific examples of the aforementioned ring, there can be cited the same as in the description of formula (cation-1) with respect to R ct1 and R ct2 The rings that can be formed by bonding with the sulfur atom to which they are bonded are the same as those exemplified.

[0504] Specific examples of the cation of the repeating unit c1 include those shown below, but are not limited to these. A Same as above.

[0505] [Chemistry 175]

[0506]

[0507] [Chemistry 176]

[0508]

[0509] [Chemistry 177]

[0510]

[0511] [Chemistry 178]

[0512]

[0513] [Chemistry 179]

[0514]

[0515] [Chemistry 180]

[0516]

[0517] [Chemistry 181]

[0518]

[0519] [Chemistry 182]

[0520]

[0521] [Chemistry 183]

[0522]

[0523] [Chemistry 184]

[0524]

[0525] In formula (c1), M - It is a non-nucleophilic counter ion. As for the aforementioned non-nucleophilic counter ions, halide ions, sulfonic acid anions, imidic acid anions and methylated acid anions are more ideal. Specific examples of the aforementioned halide ions include chloride ions and bromide ions. Specific examples of the aforementioned sulfonic acid anions (sulfonate ions) include fluoroalkylsulfonate ions such as trifluoromethanesulfonate ion, 1,1,1-trifluoroethanesulfonate ion, and nonafluorobutanesulfonate ion; arylsulfonate ions such as toluenesulfonate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, and 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as methanesulfonate ion and butanesulfonate ion; and the like. Specific examples of the aforementioned imidic acid anions (imide ions) include bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, and bis(perfluorobutylsulfonyl)imide ions. Specific examples of the aforementioned methylated acid anions (methide ions) include imide ions such as bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, and bis(perfluorobutylsulfonyl)imide ions; and tris(trifluoromethylsulfonyl)methide ions and tris(perfluoroethylsulfonyl)methide ions.

[0526] Other examples of the non-nucleophilic counter ion include anions represented by any one of the following formulae (c1-1) to (c1-4).

[0527] [Chemistry 185]

[0528]

[0529] In formula (c1-1), R fa is a fluorine atom or 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 the following: fa1 The hydrocarbon groups represented by are the same as those exemplified above.

[0530] The anion represented by the formula (c1-1) is preferably represented by the following formula (c1-1-1).

[0531] [Chemistry 186]

[0532]

[0533] In formula (c1-1-1), Q 1 and Q 2 Each of them is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. In order to improve the solubility in solvents, at least one of them is preferably a trifluoromethyl group. m is an integer of 0 to 4, and is particularly preferably 1. fa1 The hydrocarbon group may contain 1 to 35 carbon atoms and may contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, or a halogen atom, with an oxygen atom being more preferred. The hydrocarbon group is preferably one having 6 to 30 carbon atoms, in order to achieve high resolution in fine pattern formation.

[0534] In formula (c1-1-1), R fa1 The hydrocarbon group having 1 to 35 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 35 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and eicosyl; cyclic saturated hydrocarbon groups having 3 to 35 carbon atoms, such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated aliphatic hydrocarbon groups having 2 to 35 carbon atoms, such as allyl and 3-cyclohexenyl; aryl groups having 6 to 35 carbon atoms, such as phenyl, 1-naphthyl, 2-naphthyl, and 9-fluorenyl; aralkyl groups having 7 to 35 carbon atoms, such as benzyl and diphenylmethyl; and groups obtained by combining these.

[0535] Furthermore, some or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. A portion of the -CH2- group of the aforementioned hydrocarbon group may be substituted with groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. Consequently, the hydrocarbon group 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, and the like. Specific examples of hydrocarbon groups containing heteroatoms include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, and 3-oxocyclohexyl.

[0536] In formula (c1-1-1), L a1 It is a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond. From the viewpoint of synthesis, an ether bond or an ester bond is more preferable, and an ester bond is more preferable.

[0537] Specific examples of the anion represented by formula (c1-1) include those shown below, but are not limited to these. 1 Same as above, Ac is acetyl.

[0538] [Chemistry 187]

[0539]

[0540] [Chemistry 188]

[0541]

[0542] [Chemistry 189]

[0543]

[0544] [Chemistry 190]

[0545]

[0546] [Chemistry 191]

[0547]

[0548] [Chemistry 192]

[0549]

[0550] [Chemistry 193]

[0551]

[0552] [Chemistry 194]

[0553]

[0554] [Chemistry 195]

[0555]

[0556] [Chemistry 196]

[0557]

[0558] In formula (c1-2), R fb1 and R fb2 Each is independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are the same as those exemplified above. fb1 and R fb2 In particular, it is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 They can also be bonded to each other and to the groups they bond to (-CF2-SO2-N - -SO2-CF2-) together to form a ring, at this time, R fb1 and R fb2 As the groups that can be bonded to each other, fluorinated ethylene groups or fluorinated propylene groups are preferred.

[0559] In formula (c1-3), R fc1 、R fc2 and R fc3 Each is independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are the same as those exemplified above. fc1 、R fc2 and R fc3 In particular, it is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 They can also be bonded to each other and to the groups bonded to them (-CF2-SO2-C - -SO2-CF2-) together to form a ring, at this time, R fc1 and R fc2 As the groups that can be bonded to each other, fluorinated ethylene groups or fluorinated propylene groups are preferred.

[0560] In formula (c1-4), R fd is a hydrocarbon group having 1 to 40 carbon atoms which may contain heteroatoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are the same as those exemplified above.

[0561] Specific examples of the anion represented by formula (c1-4) include those shown below, but are not limited to these.

[0562] [Chemistry 197]

[0563]

[0564] [Chemistry 198]

[0565]

[0566] Examples of the aforementioned non-nucleophilic counterions include anions having an aromatic ring substituted with an iodine atom or a bromine atom. Specific examples of such anions include those represented by the following formula (c1-5).

[0567] [Chemistry 199]

[0568]

[0569] In formula (c1-5), x is an integer satisfying 1≤x≤3. y and z are integers satisfying 1≤y≤5, 0≤z≤3, and 1≤y+z≤5. y is preferably an integer satisfying 1≤y≤3, more preferably 2 or 3. z is preferably an integer satisfying 0≤z≤2.

[0570] In formula (c1-5), X BI is an iodine atom or a bromine atom, and when x and / or y is 2 or more, they may be the same as or different from each other.

[0571] In formula (c1-5), L 1 It is a saturated alkylene group having 1 to 6 carbon atoms and which may contain a single bond, an ether bond, or an ester bond. The saturated alkylene group may be linear, branched, or cyclic.

[0572] In formula (c1-5), L 2 When x is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms. When x is 2 or 3, it is a (x+1)-valent linking group having 1 to 20 carbon atoms. The linking group may also contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0573] In formula (c1-5), R feis a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbonoxy group having 1 to 20 carbon atoms, a hydrocarboncarbonyl group having 2 to 20 carbon atoms, a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms, or a hydrocarbonsulfonyloxy group having 1 to 20 carbon atoms, which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group, or an ether bond, or -N(R feA )(R feB )、-N(R feC )-C(=O)-R feD or -N(R feC )-C(=O)-OR feD . R feA and R feB Each independently represents a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. feC R is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbonoxy group having 1 to 6 carbon atoms, a saturated hydrocarboncarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarboncarbonyloxy group having 2 to 6 carbon atoms. feD It is an aliphatic hydrocarbon group having 1 to 16 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbonoxy 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, hydrocarbonoxycarbonyl group, hydrocarbon carbonyloxy group, and hydrocarbon sulfonyloxy group may be straight-chain, branched, or cyclic. When x and / or z are 2 or more, each R fe They can be the same or different from each other.

[0574] Among these, R fe For hydroxyl, -N(R feC )-C(=O)-R feD 、

[0575] -N(R feC )-C(=O)-OR feD , fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group and the like are preferred.

[0576] In formula (c1-5), Rf 11 ~Rf 14 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them is a fluorine atom or a trifluoromethyl group. 11 With Rf 12 They may also be combined to form a carbonyl group. In particular, Rf 13 and Rf 14 It is preferable that they are all fluorine atoms.

[0577] Specific examples of the anion represented by formula (c1-5) include those shown below, but are not limited to these. BI Same as above.

[0578] [Chemistry 200]

[0579]

[0580] [Chemistry 201]

[0581]

[0582] [Chemistry 202]

[0583]

[0584] [Chemistry 203]

[0585]

[0586] [Chemistry 204]

[0587]

[0588] [Chemistry 205]

[0589]

[0590] [Chemistry 206]

[0591]

[0592] [Chemistry 207]

[0593]

[0594] [Chemistry 208]

[0595]

[0596] [Chemistry 209]

[0597]

[0598] [Chemistry 210]

[0599]

[0600] [Chemistry 211]

[0601]

[0602] [Chemistry 212]

[0603]

[0604] [Chemistry 213]

[0605]

[0606] [Chemistry 214]

[0607]

[0608] [Chemistry 215]

[0609]

[0610] [Chemistry 216]

[0611]

[0612] [Chemistry 217]

[0613]

[0614] [Chemistry 218]

[0615]

[0616] [Chemistry 219]

[0617]

[0618] [Chemistry 220]

[0619]

[0620] [Chemistry 221]

[0621]

[0622] [Chemistry 222]

[0623]

[0624] As for the aforementioned non-nucleophilic counter ion, a fluorobenzenesulfonic acid anion bonded to an aromatic group containing an iodine atom described in Patent No. 6648726, anions having a mechanism of being fully decomposed by acid described in International Publication No. 2021 / 200056 and Japanese Patent Application Laid-Open No. 2021-70692, anions having a cyclic ether group described in Japanese Patent Application Laid-Open No. 2018-180525 and Japanese Patent Application Laid-Open No. 2021-35935, and anions described in Japanese Patent Application Laid-Open No. 2018-92159 can also be used.

[0625] As for the aforementioned non-nucleophilic counterions, anions of fluorine-free, highly sterically hindered (bulky) benzenesulfonic acid derivatives described in Japanese Patent Application Publication Nos. 2006-276759, 2015-117200, 2016-65016, and 2019-202974, and fluorine-free benzenesulfonic acid anions and alkylsulfonic acid anions bound to an aromatic group containing an iodine atom described in Japanese Patent Application No. 6645464 can also be used.

[0626] As for the aforementioned non-nucleophilic counter ions, the anions of disulfonic acid described in JP-A-2015-206932, the anions of sulfonic acid on one side and a different sulfonamide or sulfonylimide on the other side described in WO2020 / 158366, and the anions of sulfonic acid on one side and carboxylic acid on the other side described in JP-A-2015-24989 can also be used.

[0627] In formulas (c2) and (c3), L 1 It is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond, or a carbamate bond. Among these, an ether bond, an ester bond, or a carbonyl group is preferred from the viewpoint of synthesis, and an ester bond or a carbonyl group is more preferred.

[0628] In formula (c2), Rf 1 and Rf 2 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 1 and Rf 2 In order to increase the acid strength of the generated acid, it is more ideal that all of them are fluorine atoms. 3 and Rf 4 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 3 and Rf 4 It is preferred that at least one of the groups is a trifluoromethyl group.

[0629] In formula (c3), Rf 5 and Rf 6 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 5 and Rf 6 Among these, Rf 5 and Rf 6 It is preferred that at least one of the groups is a trifluoromethyl group.

[0630] In formulae (c2) and (c3), d is 0, 1, 2 or 3, and preferably 1.

[0631] Specific examples of the anion of the repeating unit c2 include those shown below, but are not limited to these. A Same as above.

[0632] [Chemistry 223]

[0633]

[0634] [Chemistry 224]

[0635]

[0636] [Chemistry 225]

[0637]

[0638] [Chemistry 226]

[0639]

[0640] [Chemistry 227]

[0641]

[0642] [Chemistry 228]

[0643]

[0644] [Chemistry 229]

[0645]

[0646] Specific examples of the anion of the repeating unit c3 include those shown below, but are not limited to these. A Same as above.

[0647] [Chemistry 230]

[0648]

[0649] [Chemistry 231]

[0650]

[0651] [Chemistry 232]

[0652]

[0653] [Chemistry 233]

[0654]

[0655] [Chemistry 234]

[0656]

[0657] [Chemistry 235]

[0658]

[0659] [Chemistry 236]

[0660]

[0661] [Chemistry 237]

[0662]

[0663] [Chemistry 238]

[0664]

[0665] Specific examples of the anion of the repeating unit represented by formula (c4) include those shown below, but are not limited to these. A Same as above.

[0666] [Chemistry 239]

[0667]

[0668] In formulas (c2) to (c4), A + is an onium cation. Examples of the onium cation include ammonium cations, sulfonium cations, and iodonium cations, with sulfonium cations and iodonium cations being preferred. Specific examples thereof include the same ones as those exemplified for the sulfonium cation represented by formula (cation-1), the iodonium cation represented by formula (cation-2), and the ammonium cation represented by formula (cation-3).

[0669] As specific structures of the repeating units c1 to c4, there can be mentioned any combination of anions and cations as described above.

[0670] Among repeating units c1 to c4, repeating units c2, c3, and c4 are more ideal from the perspective of controlling acid diffusion, repeating units c2 and c4 are more ideal from the perspective of the acid strength of the generated acid, and repeating unit c2 is even more ideal from the perspective of solvent solubility.

[0671] The base polymer may further contain a repeating unit having a structure in which a hydroxyl group is protected by an acid-labile group (hereinafter also referred to as repeating unit d). The repeating unit d is not particularly limited as long as it has a structure in which one or more hydroxyl groups are protected and the protecting group decomposes upon the action of an acid to generate a hydroxyl group. However, the repeating unit d is preferably represented by the following formula (d1).

[0672] [Chemistry 240]

[0673]

[0674] In formula (d1), R A Same as above. 41 It is a (e+1)-valent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. 42 is an acid-labile group. e is an integer of 1 to 4.

[0675] In formula (d1), R 42 The acid-labile group represented by R may be any one that is deprotected by the action of an acid and generates a hydroxyl group. 42 The structure of is not particularly limited, and is preferably an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (d2), or the like, and particularly preferably an alkoxymethyl group represented by the following formula (d2).

[0676] [Chemistry 241]

[0677]

[0678] In the formula, * represents an atomic bond. 43 It is a hydrocarbon group having 1 to 15 carbon atoms.

[0679] R 42 Specific examples of the acid-labile group represented by the alkoxymethyl group and the repeating unit d represented by formula (d2) include the same ones as exemplified in the description of the repeating unit d described in JP-A-2020-111564.

[0680] The base polymer may further contain a repeating unit e derived from indene, benzofuran, benzothiophene, acenaphthene, chromone, coumarin, norbornadiene, or a derivative thereof. Specific examples of monomers providing the repeating unit e include those shown below, but are not limited thereto.

[0681] [Chemistry 242]

[0682]

[0683] The aforementioned base polymer may further contain repeating units f derived from dihydroindane, vinylpyridine or vinylcarbazole.

[0684] In the polymer of the present invention, the content ratios of the repeating units a1, a2, b1, b2, c1, c2, c3, c4, d, e, and f are preferably 0 < a1 ≤ 0.8, 0 ≤ a2 ≤ 0.8, 0 ≤ b1 ≤ 0.6, 0 ≤ b2 ≤ 0.6, 0 ≤ c1 ≤ 0.4, 0 ≤ c2 ≤ 0.4, 0 ≤ c3 ≤ 0.4, 0 ≤ c4 ≤ 0.4, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.3, and 0 ≤ f ≤ 0.3, and more preferably 0 < a1 ≤ 0.7, 0 ≤ a2 ≤ 0.7, 0 ≤ b1 ≤ 0.5, 0 ≤ b2 ≤ 0.5, 0 ≤ c1 ≤ 0.3, 0 ≤ c2 ≤ 0.3, 0 ≤ c3 ≤ 0.3, 0 ≤ c4 ≤ 0.3, 0 ≤ d ≤ 0.3, 0 ≤ e ≤ 0.3, and 0 ≤ f ≤ 0.3. However, a1 + a2 + b1 + b2 + c1 + c2 + c3 + c4 + d + e + f ≤ 1.0.

[0685] 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 risk of reduced resolution due to the inability to ensure the difference in dissolution rate before and after exposure. In addition, in the present invention, Mw is a polystyrene conversion measurement value obtained by gel permeation chromatography (GPC) using THF or N,N-dimethylformamide (DMF) as a solvent.

[0686] Then, regarding the molecular weight distribution (Mw / Mn) of the aforementioned polymer, as the pattern rule becomes finer, the influence of Mw / Mn tends to become larger. In order to obtain a resist composition that can be ideally used for fine pattern sizes, a narrow distribution with Mw / Mn of 1.0 to 2.0 is preferable. If it is within the above range, there are fewer low-molecular-weight and high-molecular-weight polymers, and there is no risk of foreign substances occurring on the pattern or deterioration of the pattern shape after exposure.

[0687] When synthesizing the aforementioned polymer, for example, monomers providing the aforementioned repeating units can be added with a radical polymerization initiator in an organic solvent and heated to carry out polymerization.

[0688] Specific examples of organic solvents used during polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyrolactone (GBL). Specific examples of the 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, and lauroyl peroxide. The amount of these initiators added is preferably 0.01 to 25 mol% relative to the total amount of the monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and from the perspective of production efficiency, 2 to 12 hours is more preferably.

[0689] The aforementioned polymerization initiator can also be added to the aforementioned monomer solution and supplied to the reactor, or an initiator solution can be prepared separately from the aforementioned monomer solution and supplied to the reactor independently. Because there is a possibility that the polymerization reaction will proceed and generate ultra-high molecular weight bodies due to the free radicals generated by the initiator during the standby time, it is ideal to prepare the monomer solution and the initiator solution independently and add them dropwise from the perspective of quality management. The acid-labile group can also be used in its original state and introduced into the monomer, or it can be protected or partially protected after polymerization. In addition, for the purpose of adjusting the molecular weight, a well-known chain transfer agent such as dodecanethiol or 2-mercaptoethanol can also be used in combination. At this time, the amount of these chain transfer agents added is preferably 0.01 to 20 mol% relative to the total amount of the monomers to be polymerized.

[0690] In the case of monomers containing hydroxyl groups, the hydroxyl groups can be replaced with acetal groups such as ethoxyethoxy groups that are easily deprotected by acid during polymerization, and then deprotected by weak acid and water after polymerization. Alternatively, the hydroxyl groups can be replaced with acetyl groups, formyl groups, pivaloyl groups, etc., and then alkaline hydrolysis can be performed after polymerization.

[0691] When copolymerizing hydroxystyrene and hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers may be added with a free radical polymerization initiator in an organic solvent and heated for polymerization. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene may be used, and after polymerization, the acetoxy group may be deprotected by alkaline hydrolysis to obtain polyhydroxystyrene or hydroxyvinylnaphthalene.

[0692] The base used in the alkaline hydrolysis may be aqueous ammonia, triethylamine, or the like. 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.

[0693] The amount of each monomer in the monomer solution can be appropriately set, for example, so as to achieve a preferred content ratio of the repeating unit.

[0694] The polymer obtained by the aforementioned production method can be made into a final product by a polymerization reaction of the obtained reaction solution, or the polymerization solution can be added to a poor solvent and subjected to a purification step such as a reprecipitation method to obtain a powder, and then the obtained powder is processed into the final product. However, considering the viewpoints of operating efficiency and quality stability, it is more ideal to process the powder obtained by the purification step into a polymer solution dissolved in a solvent as the final product.

[0695] 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, and the like. Ethers such as ether, diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; lactones such as GBL; alcohols such as diacetone alcohol (DAA); high-boiling point alcohol solvents such as diethylene glycol, propylene glycol, glycerol, 1,4-butanediol, and 1,3-butanediol; and mixed solvents thereof.

[0696] The concentration of the polymer in the polymer solution is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0697] The reaction solution and polymer solution are preferably filtered through a filter medium. Filtering through a filter medium can remove foreign matter and gel that may cause defects, which is effective in terms of quality stability.

[0698] With regard to the material of the filter material used in the aforementioned filter material filtration, materials such as fluorocarbon, cellulose, nylon, polyester, hydrocarbon can be cited. In the filtering step of the resist composition, it is more ideal to use a filter material formed by hydrocarbons such as fluorocarbon, polyethylene, polypropylene, or nylon, which are called so-called Teflon (registered trademark). The pore size of the filter material can be appropriately selected in accordance with the set target of the cleanliness, and is more ideally less than 100nm, and more ideally less than 20nm. In addition, these filter materials can be used alone or in combination. The filtering method can make the solution pass only once, but it is more ideal to circulate the solution and filter several times. The filtering step can be carried out in any order and number of times in the manufacturing step of the polymer, but it is more ideal to filter the reaction solution after the polymerization reaction, the polymer solution, or both thereof.

[0699] The base polymer (B) may be used alone or in combination of two or more polymers having different composition ratios, Mw, and / or Mw / Mn. Furthermore, the base polymer (B) may contain, in addition to the aforementioned polymers, a hydrogenated ring-opening metathesis polymer. In this regard, the polymers described in Japanese Patent Application Laid-Opening No. 2003-66612 may be used.

[0700] [(C) Organic solvent]

[0701] The chemically amplified resist composition of the present invention may also contain an organic solvent as component (C). The organic solvent (C) 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; ketoalcohols such as DAA; ethers such as PGME, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; lactones such as GBL; and mixed solvents thereof.

[0702] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixed solvents thereof are particularly preferred because they have excellent solubility in the base polymer of the component (B).

[0703] In the chemically amplified resist composition of the present invention, the content of the organic solvent (C) is preferably 200 to 5000 parts by mass, and more preferably 400 to 3500 parts by mass, relative to 80 parts by mass of the base polymer (B). The organic solvent (C) may be used alone or in combination of two or more.

[0704] [(D) Photoacid generator]

[0705] The chemically amplified resist composition of the present invention may also contain a photoacid generator as component (D). The photoacid generator is not particularly limited as long as it generates an acid stronger than the sulfonic acid generated by the quencher (component (A)) upon irradiation with high-energy radiation.

[0706] Preferable photoacid generators include those represented by the following formula (2) or (3).

[0707] [Chemistry 243]

[0708]

[0709] In formula (2), R 101 ~R 105 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. 101 、R 102 and R 103 Any two of them may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Specific examples of the aforementioned hydrocarbon groups include those described in the formulas (cation-1) and (cation-2) with respect to R ct1 ~R ct5 The hydrocarbon groups represented by are the same as those exemplified above.

[0710] Specific examples of the cation of the sulfonium salt represented by formula (2) include the same ones as those exemplified for the sulfonium cation represented by formula (cation-1). Specific examples of the cation of the iodonium salt represented by formula (3) include the same ones as those exemplified for the iodonium cation represented by formula (cation-2).

[0711] In formulas (2) and (3), Xa - Specific examples of the anion of the strong acid include those represented by any one of formulae (c1-1) to (c1-5).

[0712] Furthermore, the photoacid generator of the component (D) is preferably represented by the following formula (4).

[0713] [Chemistry 244]

[0714]

[0715] In formula (4), R 201 and R 202 Each independently represents a hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. 203 is a C1-30 alkylene group which may contain a hetero atom. 201 、R 202 and R 203 Any two of them may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

[0716] R 201 and R 202 The hydrocarbon group having 1 to 30 carbon atoms represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6 ] Cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, such as decyl and adamantyl; aryl groups having 6 to 30 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl and anthracenyl; groups derived from combinations thereof, etc. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing 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 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.

[0717] R 203The alkylene group having 1 to 30 carbon atoms may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, and octane-1,20-diyl. Alkanediyl groups having 1 to 30 carbon atoms, such as heptadecane-1,17-diyl, etc.; cyclic saturated alkylene groups having 3 to 30 carbon atoms, such as cyclopentanediyl, cyclohexanediyl, norbornanediyl, and adamantanediyl; arylene groups, such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, and tert-butylnaphthylene; and the like. Furthermore, some or all of the hydrogen atoms of the aforementioned hydrocarbylene group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms. Furthermore, some of the -CH2- groups of the aforementioned hydrocarbylene group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms. Consequently, the hydrocarbylene 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, or the like. The aforementioned heteroatom is preferably an oxygen atom.

[0718] In formula (4), L 11 is a single bond, an ether bond, or an alkylene group having 1 to 20 carbon atoms and which may contain heteroatoms. The aforementioned alkylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: 203 The alkylene groups exemplified are the same as those exemplified above.

[0719] 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.

[0720] The photoacid generator represented by formula (4) is preferably represented by the following formula (4').

[0721] [Chemistry 245]

[0722]

[0723] In formula (4'), L 11 Same as above. X e R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 、R 302 and R 303 Each is independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain 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 by are the same as those exemplified above. p and q are each independently an integer of 0 to 5, and r is an integer of 0 to 4.

[0724] Specific examples of the photo-acid generator represented by formula (4) include the same ones as exemplified for the photo-acid generator represented by formula (2) in JP-A-2017-26980.

[0725] Among the aforementioned photoacid generators, those containing anions represented by formula (c1-1-1) or (c1-4) are particularly preferred because they have low acid diffusion and excellent solubility in solvents. Furthermore, those represented by formula (4') are particularly preferred because they have extremely low acid diffusion.

[0726] When the chemically amplified resist composition of the present invention includes a photoacid generator (D), its content is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass, relative to 80 parts by mass of the base polymer (B). When the amount of the photoacid generator (D) added falls within the aforementioned range, resolution is improved and there is no risk of foreign matter issues occurring after development or during stripping of the resist film. The photoacid generators (D) may be used alone or in combination of two or more.

[0727] [(E) Other quenchers]

[0728] The chemically amplified resist composition of the present invention may contain a quencher other than the component (A) (hereinafter also referred to as other quencher) as the component (E).

[0729] Specific examples of other quenchers of the component (E) include onium salts represented by the following formula (5).

[0730] [Chemistry 246]

[0731]

[0732] In formula (5), R401 It is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom.

[0733] Just R 401 Specific examples of the hydrocarbon group having 1 to 40 carbon atoms include alkyl groups having 1 to 40 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbon groups having 3 to 40 carbon atoms, such as decyl and adamantyl; aryl groups having 6 to 40 carbon atoms, such as phenyl, naphthyl, anthracenyl, etc. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and part of the -CH2- of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. 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 acid anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may also be contained. In addition, with respect to R 401 Examples of the fluorinated saturated hydrocarbon groups include trifluoromethyl and trifluoroethyl groups, and fluorinated aryl groups include pentafluorophenyl and 4-trifluoromethylphenyl groups.

[0734] Specific examples of the anion of the onium salt represented by formula (5) include those shown below, but are not limited to these.

[0735] [Chemistry 247]

[0736]

[0737] [Chemistry 248]

[0738]

[0739] [Chemistry 249]

[0740]

[0741] In formula (5), Mq + The onium cation is preferably a sulfonium cation represented by the above formula (cation-1), an iodonium cation represented by the above formula (cation-2), or an ammonium cation represented by the above formula (cation-3).

[0742] Specific examples of the onium salt represented by formula (5) include any combination of the aforementioned anions and cations. Furthermore, these onium salts can be readily prepared by ion exchange reactions using known organic chemical methods. For ion exchange reactions, for example, Japanese Patent Application Publication No. 2007-145797 can be used as a reference.

[0743] The onium salt represented by formula (5) functions as a quencher in the chemically amplified resist composition of the present invention. This is because each counter anion of the onium salt is a conjugate base of a weak acid. Here, a weak acid refers to an acid that exhibits insufficient acidity to deprotect the acid-labile group of the unit containing the acid-labile group used in the base polymer. The onium salt represented by formula (5) functions as a quencher when used in combination with an onium salt-type photoacid generator having a conjugate base of a strong acid such as sulfonic acid as a counter anion. That is, when an onium salt that generates a strong acid such as sulfonic acid and an onium salt that generates a weak acid such as carboxylic acid are mixed and used, if the strong acid generated from the photoacid generator due to irradiation with high-energy radiation collides with the onium salt having unreacted weak acid anions, the weak acid is released due to salt exchange, and an onium salt having a strong acid anion is generated. Through this process, the strong acid is exchanged for a weak acid with lower catalytic energy, so the acid is apparently deactivated and the acid diffusion can be controlled.

[0744] In addition, as for other quenchers of component (E), onium salts having a sulfonium cation and a phenoxide anion site in the same molecule as described in Japanese Patent No. 6848776, onium salts having a sulfonium cation and a carboxylate anion site in the same molecule as described in Japanese Patent No. 6583136 and Japanese Patent Application Laid-Open No. 2020-200311, and onium salts having an iodonium cation and a carboxylate anion site in the same molecule as described in Japanese Patent No. 6274755 can also be used.

[0745] Here, when the photoacid generator that generates a strong acid is an onium salt, as described above, the generated strong acid can be exchanged for a weak acid by irradiation with high-energy radiation. However, it is believed that the weak acid generated by irradiation with high-energy radiation is less likely to collide with the onium salt that generates the unreacted strong acid, leading to salt exchange. This is because the onium cation is more likely to form an ion pair with the anion of the stronger acid.

[0746] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (5) as component (E), i.e., an additional quencher, its content is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, relative to 80 parts by mass of the base polymer (B). When the content of the onium salt quencher falls within the aforementioned range, resolution is excellent and sensitivity is not significantly reduced, which is preferable. The onium salt represented by formula (5) can be used alone or in combination of two or more.

[0747] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as component (E), i.e., another quencher. Specific examples of such nitrogen-containing compounds include primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate bond. Furthermore, compounds described in JP-A-3790649, and compounds in which primary or secondary amines are protected with carbamate groups, are also included.

[0748] Alternatively, a sulfonium sulfonate salt with a nitrogen-containing substituent can be used as the nitrogen-containing compound. This compound functions as a quencher in the unexposed area, but loses its quenching properties in the exposed area due to neutralization with the acid generated by the compound itself, and functions as a so-called photodestructive base. The use of a photodestructive base can enhance the contrast between the exposed and unexposed areas. For example, Japanese Patent Application Publication No. 2009-109595 and Japanese Patent Application Publication No. 2012-46501 can be used as reference for photodestructive bases.

[0749] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as component (E), i.e., an additional quencher, its content is preferably 0.001 to 12 parts by mass, and more preferably 0.01 to 8 parts by mass, relative to 80 parts by mass of the base polymer (B). The nitrogen-containing compound may be used alone or in combination of two or more.

[0750] [(F) Surfactant]

[0751] The chemically amplified resist composition of the present invention may further contain a surfactant as component (F). The surfactant of component (F) is preferably a surfactant that is insoluble or poorly soluble in water but soluble in an alkaline developer, or a surfactant that is insoluble or poorly soluble in both water and an alkaline developer. Such surfactants can be found in Japanese Patent Application Publication Nos. 2010-215608 and 2011-16746.

[0752] As for surfactants that are insoluble or poorly soluble in water and alkaline developers, among the surfactants described in the aforementioned publications, FC-4430 (manufactured by 3M Co., Ltd.), Surflon (registered trademark) S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Olfine (registered trademark) E1004 (manufactured by Nissin Chemical Co., Ltd.), KH-20 and KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and oxetane ring-opening polymers represented by the following formula (surf-1) are preferable.

[0753] [Chemistry 250]

[0754]

[0755] Here, R, Rf, A, B, C, m, and n are not related to the above description and are used only in formula (surf-1). R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. Examples of the divalent aliphatic groups include ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, and 1,5-pentylene. Examples of the trivalent and tetravalent aliphatic groups include the following.

[0756] [Chemistry 251]

[0757]

[0758] In the formula, the dotted lines represent atomic bonds, and each is a partial structure derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0759] Among them, 1,4-butylene group and 2,2-dimethyl-1,3-propylene group are particularly preferred.

[0760] Rf is a trifluoromethyl group or a pentafluoroethyl group, and is preferably a trifluoromethyl group. m is an integer from 0 to 3, n is an integer from 1 to 4, and the sum of n and m is the valence of R, which is an integer from 2 to 4. A is 1. B is an integer from 2 to 25, and is preferably an integer from 4 to 20. C is an integer from 0 to 10, and is 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 production of surfactants based on partially fluorinated oxetane ring-opening polymers, see the specification of U.S. Patent No. 5,650,483.

[0761] Surfactants that are insoluble or poorly soluble in water but soluble in alkaline developers have the function of reducing water penetration and leaching by aligning to the surface of the resist film when a resist overcoat is not used in ArF immersion lithography. Therefore, they are useful for suppressing the dissolution of water-soluble components from the resist film, thereby reducing damage to the exposure apparatus. Furthermore, they are solubilized during aqueous alkaline development after exposure or post-exposure baking (PEB), making them less likely to form foreign matter that can cause defects. This type of surfactant, which is insoluble or poorly soluble in water but soluble in alkaline developers, is a polymeric surfactant, also known as a hydrophobic resin. Those with high water repellency and improved water slip properties are particularly desirable.

[0762] Specific examples of such polymeric surfactants include those containing at least one repeating unit selected from the group consisting of repeating units represented by any one of the following formulae (6A) to (6E).

[0763] [Chemistry 252]

[0764]

[0765] In formulas (6A) to (6E), R B W is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 It is -CH2-, -CH2CH2-, -O- or two -H separated from each other. s1 Each independently represents 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, the carbon-carbon bonds may be separated by ether bonds or carbonyl groups. 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 The group represented by R 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 the carbon-carbon bonds thereof may be separated by ether bonds or carbonyl groups.

[0766] R s1 The hydrocarbon group having 1 to 10 carbon atoms represented by is preferably a saturated hydrocarbon group, and may be linear, branched, or cyclic. Specific examples 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. Of these, those having 1 to 6 carbon atoms are particularly preferred.

[0767] R s2 The alkylene group represented by is preferably a saturated alkylene group, and may be linear, branched, or cyclic. Specific examples thereof include methylene, ethylene, propylene, butylene, and pentylene.

[0768] R s3 or R s6 The hydrocarbon group represented by may be saturated or unsaturated, and may be straight chain, branched, or cyclic. Specific examples thereof include saturated hydrocarbon groups, alkenyl groups, alkynyl groups, and other aliphatic unsaturated hydrocarbon groups, and saturated hydrocarbon groups are more preferred. s1In addition to the hydrocarbon groups exemplified above, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl and the like can be mentioned. s3 or R s6 As for the fluorinated hydrocarbon groups represented by , some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon groups are substituted with fluorine atoms. As mentioned above, these carbon-carbon bonds may be separated by ether bonds or carbonyl groups.

[0769] Just R s3 Specific examples of the acid-labile group include groups represented by the aforementioned 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 and 4 to 20 carbon atoms.

[0770] R s4 The (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group represented by may be linear, branched, or cyclic. Specific examples thereof include groups obtained by removing u hydrogen atoms from the aforementioned hydrocarbon group or fluorinated hydrocarbon group.

[0771] R sa The fluorinated hydrocarbon group represented by is preferably saturated and may be linear, branched, or cyclic. Specific examples thereof include those in which some or all of the hydrogen atoms of the aforementioned hydrocarbon groups are substituted with fluorine atoms, such as trifluoromethyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoro-1-propyl, 3,3,3-trifluoro-2-propyl, 2,2,3,3-tetrafluoropropyl, 1,1,1,3,3,3-hexafluoroisopropyl, 2,2,3,3,4,4,4-heptafluorobutyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, and 2-(perfluorodecyl)ethyl.

[0772] Specific examples of the repeating unit represented by any one of formulae (6A) to (6E) include those shown below, but are not limited thereto. B Same as above.

[0773] [Chemistry 253]

[0774]

[0775] [Chemistry 254]

[0776]

[0777] [Chemistry 255]

[0778]

[0779] [Chemistry 256]

[0780]

[0781] [Chemistry 257]

[0782]

[0783] [Chemistry 258]

[0784]

[0785] The aforementioned polymeric surfactant may further contain repeating units other than the repeating units represented by formulae (6A) to (6E). Specific examples of such repeating units include repeating units derived from methacrylic acid and α-trifluoromethylacrylic acid derivatives. In the polymeric surfactant, the content of the repeating units represented by formulae (6A) to (6E) is preferably 20 mol% or more, more preferably 60 mol% or more, and even more preferably 100 mol% of the total repeating units.

[0786] The polymer surfactant preferably has an Mw of 1,000 to 500,000, more preferably 3,000 to 100,000, and an Mw / Mn of 1.0 to 2.0, more preferably 1.0 to 1.6.

[0787] Methods for synthesizing the aforementioned polymeric surfactants include, for example, a method in which a monomer containing an unsaturated bond that provides a repeating unit represented by formulas (6A) to (6E), and optionally other repeating units, is placed in an organic solvent, a free radical initiator is added, and the mixture is heated to polymerize. Specific examples of organic solvents used in the polymerization include toluene, benzene, THF, diethyl ether, and dioxane. Specific examples of polymerization initiators include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The reaction temperature is preferably 50-100°C. The reaction time is preferably 4-24 hours. Acid-labile groups may be directly introduced into the monomer, or they may be protected or partially protected after polymerization.

[0788] When synthesizing the aforementioned polymeric surfactant, a known chain transfer agent such as dodecanethiol or 2-mercaptoethanol may be used to adjust the molecular weight. In this case, the amount of such chain transfer agent added is preferably 0.01 to 10 mol % relative to the total molar number of the monomers to be polymerized.

[0789] When the chemically amplified resist composition of the present invention includes a surfactant (F), 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 base polymer (B). When the surfactant (F) content is 0.1 parts by mass or greater, the receding contact angle of the resist film surface with water is sufficiently improved. When the surfactant (F) content is 50 parts by mass or less, the dissolution rate of the resist film surface in the developer is slow, thereby ensuring sufficient height of the formed fine pattern. The surfactant (F) can be used alone or in combination of two or more.

[0790] [(G) Other ingredients]

[0791] The chemically amplified resist composition of the present invention may also contain, as (G) other components, compounds that decompose and generate acid (acid-proliferating compounds), organic acid derivatives, fluorinated alcohols, and compounds with an Mw of 3,000 or less whose solubility in a developer changes due to the action of acid (dissolution inhibitors). The acid-proliferating compounds described in Japanese Patent Application Laid-Open No. 2009-269953 or Japanese Patent Application Laid-Open No. 2010-215608 can be referenced. When the acid-proliferating compound is included, its content is preferably 0 to 5 parts by mass, and more preferably 0 to 3 parts by mass, relative to 80 parts by mass of the base polymer (B). Excessive content makes it difficult to control acid diffusion, potentially leading to degradation of resolution and pattern shape. The organic acid derivatives, fluorinated alcohols, and dissolution inhibitors described in Japanese Patent Application Laid-Open No. 2009-269953 or Japanese Patent Application Laid-Open No. 2010-215608 can be referenced.

[0792] [Pattern Formation Method]

[0793] The pattern forming method of the present invention comprises the steps of forming a resist film on a substrate using the chemically amplified resist composition, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0794] As for the aforementioned substrate, a substrate for integrated circuit manufacturing (Si, SiO2, SIn, SiON, TIn, WSi, BPSG, SOG, organic anti-reflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) can be used.

[0795] The resist film can be formed by, for example, applying the chemically amplified resist composition described above onto a substrate by spin coating or the like to a film thickness of preferably 0.05 to 2 μm, and pre-baking the film on a hot plate at preferably 60 to 150° C. for 1 to 10 minutes, more preferably 80 to 140° C. for 1 to 5 minutes.

[0796] Examples of high-energy radiation used for exposure of the resist film include KrF excimer laser, ArF excimer laser, EB, and EUV. When KrF excimer laser, ArF excimer laser, or EUV is used for exposure, a mask for forming a target pattern is used and the exposure dose is preferably 1 to 200 mJ / cm 2 , more ideally 10 to 100 mJ / cm 2 When using EB, a mask for forming the target pattern or directly using an exposure dose of 1 to 300 μC / cm is ideal. 2 , more ideally 10 to 200 μC / cm 2 irradiation in the manner of .

[0797] In addition to the usual exposure method, an immersion method in which a liquid with a refractive index of 1.0 or higher is placed between the resist film and the projection lens may be used for exposure. In this case, a protective film insoluble in water may also be used.

[0798] The aforementioned water-insoluble protective film is used to prevent the incorporation of eluted products from the resist film and improve the water slip properties of the film surface. It can be broadly divided into two types. One is an organic solvent stripper, which must be removed prior to alkaline aqueous development using an organic solvent that does not dissolve the resist film. The other is an alkaline aqueous solution-soluble type, which is soluble in an alkaline developer and removes the protective film simultaneously with the removal of the soluble portion of the resist film. The latter is particularly preferably based on a water-insoluble but alkaline developer-soluble polymer containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue, which is soluble in alcohols with 4 or more carbon atoms, ethers with 8 to 12 carbon atoms, or mixtures thereof. Alternatively, the aforementioned water-insoluble but alkaline developer-soluble surfactant can be dissolved in an alcohol with 4 or more carbon atoms, an ether with 8 to 12 carbon atoms, or mixtures thereof.

[0799] After exposure, PEB can be performed, for example, by heating on a hot plate at preferably 60-150° C. for 1-5 minutes, more preferably 80-140° C. for 1-3 minutes.

[0800] Development is performed, for example, using a developer containing an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) preferably at 0.1 to 5% by mass, more preferably at 2 to 3% by mass, by a general method such as a dip method, a puddle method, or a spray method for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, thereby dissolving the exposed portion and forming a desired pattern on the substrate.

[0801] After the resist film is formed, pure water rinsing may be performed to extract an acid generator or the like from the film surface or to wash away particles. Rinsing may also be performed to remove water remaining on the film after exposure.

[0802] Then, patterning can also be performed using a double patterning method. Examples of the double patterning method include a trench method in which a substrate with a 1:3 trench pattern is processed using a first exposure and etching process, and then a second exposure is performed after shifting the position to form a 1:3 trench pattern and a 1:1 pattern. A line method in which a first substrate with a 1:3 isolation pattern is processed using a first exposure and etching process, and then a second substrate with a 1:3 isolation pattern formed under the first substrate is processed using a second exposure process after shifting the position to form a 1:1 pattern with half the pitch is formed.

[0803] In the pattern forming method of the present invention, a negative tone development method in which an organic solvent is used as a developer to dissolve the unexposed portion may be used.

[0804] In the above-mentioned organic solvent development, as a developer, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, Ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0805] Example

[0806] Hereinafter, the present invention will be described in detail with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples.

[0807] MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0808] [1] Synthesis of onium salts

[0809] [Example 1-1] Synthesis of Onium Salt PDQ-1

[0810] [Chemistry 259]

[0811]

[0812] (1) Synthesis of intermediate In-1

[0813] Under a nitrogen environment, raw material SM-1 (50.0 g), potassium carbonate (27.4 g), and sodium iodide (2.7 g) were dissolved in DMF (300 g) in a reaction vessel and heated to an internal temperature of 45°C. Afterwards, raw material SM-2 (23.9 g) was added dropwise. After the addition, the temperature was raised to an internal temperature of 65°C and matured for 18 hours. After maturation, the reaction solution was cooled in an ice bath, and water (300 g) was added dropwise to stop the reaction. Ethyl acetate (250 mL) and toluene (150 ml) were added to extract the target product, and a conventional aqueous work-up was performed. The solvent was distilled off to obtain 61.6 g (yield 95%) of intermediate In-1 as an oil.

[0814] (2) Synthesis of onium salt PDQ-1

[0815] Under a nitrogen environment, the intermediate In-1 (10.9 g) was dissolved in THF (50 g) in a reaction vessel and the temperature was raised to 45°C. After that, a 25% by mass aqueous sodium hydroxide solution (6.2 g) was added dropwise. After the addition, the mixture was matured for 13 hours while maintaining the internal temperature at 45°C. After confirming the disappearance of the intermediate In-1 by thin layer chromatography, the reaction solution was cooled to room temperature. After cooling, raw material SM-3 (14.3 g) and methyl isobutyl ketone (100 g) and water (50 g) were added and stirred at room temperature for 30 minutes. After stirring, the organic layer was separated and sampled, washed with water, and then concentrated under reduced pressure. The concentrate was refined by silica gel chromatography to obtain 16.7 g (yield 84%) of the target onium salt PDQ-1 in the form of an oily substance.

[0816] The results of TOF-MS of PDQ-1 are shown below.

[0817] MALDI TOF-MS:POSITIVE M + 317 (equivalent to C 18 H 12 F3S + )

[0818] NEGATIVE M - 347 (equivalent to C 12 H 12 IO4 - )

[0819] [Examples 1-2 to 1-7] Synthesis of Onium Salts PDQ-2 to PDQ-7

[0820] Onium salts PDQ-2 to PDQ-7 represented by the following formulae were synthesized using corresponding raw materials and known organic chemical reactions.

[0821] [Chemistry 260]

[0822]

[0823] [Synthesis Example] Synthesis of base polymers (polymers P-1 to P-5)

[0824] The monomers were combined and copolymerized in MEK as a solvent, and then added to hexane. The precipitated solid was washed with hexane, separated, and dried to obtain base polymers (polymers P-1 to P-5) with the following compositions. 1 The product was confirmed by H-NMR, and Mw and Mw / Mn were confirmed by GPC (solvent: DMF, standard: polystyrene).

[0825] [Chemistry 261]

[0826]

[0827] [3] Preparation of chemically amplified resist compositions

[0828] [Examples 2-1 to 2-30, Comparative Examples 1-1 to 1-20]

[0829] The quenchers of the present invention (PDQ-1 to PDQ-7), comparative quenchers (PDQ-A to PDQ-D), photoacid generators (PAG-X, PAG-Y), base polymers (P-1 to P-5), and other quenchers (AQ-1, AQ-2) having the compositions shown in Tables 1 and 2 below were dissolved in a solvent containing 0.01 mass % of surfactant A (Omnova) to prepare solutions. These solutions were then filtered through a 0.2 μm Teflon (registered trademark) filter to prepare chemically amplified resist compositions (R-1 to R-30 and CR-1 to CR-20).

[0830] [Table 1]

[0831]

[0832] [Table 2]

[0833]

[0834]

[0835] In Tables 1 and 2, the solvent, photoacid generators PAG-X and PAG-Y, comparative quenchers PDQ-A to PDQ-D, other quenchers AQ-1 and AQ-2, and surfactant A are as follows.

[0836] Solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0837] DAA (Diacetone Alcohol)

[0838] Photoacid generators: PAG-X, PAG-Y

[0839] [Chemistry 262]

[0840]

[0841] Comparative quenchers: PDQ-A to PDQ-D

[0842] [Chemistry 263]

[0843]

[0844] Other quenchers: AQ-1, AQ-2

[0845] [Chemistry 264]

[0846]

[0847] Surfactant A: 3-methyl-3-(2,2,2-trifluoroethoxymethyl)oxetane, tetrahydrofuran, and 2,2-dimethyl-1,3-propanediol copolymer (manufactured by Omnova)

[0848] [Chemistry 265]

[0849]

[0850] a:(b+b'):(c+c')=1:4~7:0.01~1 (molar ratio)

[0851] Mw=1500

[0852] [4]EUV lithography evaluation (1)

[0853] [Examples 3-1 to 3-30, Comparative Examples 2-1 to 2-20]

[0854] Each chemically amplified resist composition (R-1 to R-30, CR-1 to CR-20) was spin-coated onto a Si substrate on which a 20 nm thick silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed. The film was pre-baked at 100°C for 60 seconds using a hot plate to form a 50 nm thick resist film. The resist film was exposed to light using an EUV scanner NXE3400 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, dipole illumination) while varying the exposure dose and focus (exposure dose pitch: 1 mJ / cm 2 While exposing an LS pattern with a size of 18 nm and a pitch of 36 nm on the wafer (with a focal pitch of 0.020 μm), PEB was performed for 60 seconds at the temperatures shown in Tables 3 and 4. This was followed by immersion development for 30 seconds in a 2.38 mass% TMAH aqueous solution, rinsing with a rinse material containing a surfactant, and spin drying to obtain a positive pattern.

[0855] The obtained LS pattern was observed using a CD-SEM (CG6300) manufactured by Hitachi Advanced Technologies Co., Ltd., and the sensitivity, EL, LWR, depth of focus (DOF), and collapse limit were evaluated according to the following methods. The results are shown in Tables 3 and 4.

[0856] [Sensitivity evaluation]

[0857] Determine the optimal exposure E to obtain an LS pattern with a line width of 18 nm and a pitch of 36 nm. op (mJ / cm 2 ) as the sensitivity. The smaller the value, the higher the sensitivity.

[0858] [EL evaluation]

[0859] The EL (unit: %) was calculated from the following formula for the exposure dose formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm interval width in the LS pattern. The larger the value, the better the performance.

[0860] EL(%)=(|E1-E2| / E op )×100

[0861] E1: Provides the optimal exposure for LS patterns with a line width of 16.2nm and a pitch of 36nm

[0862] E2: Provides the optimal exposure for LS patterns with a line width of 19.8nm and a pitch of 36nm

[0863] E op :Provides the optimal exposure for LS patterns with a line width of 18nm and a pitch of 36nm

[0864] [LWR evaluation]

[0865] Will be E op The LS pattern obtained by irradiation was measured at 10 locations along the longitudinal direction of the line. From the results, the value (3σ) tripled from the standard deviation (σ) was calculated as LWR. The smaller the value, the less roughness and more uniform the line width of the pattern.

[0866] [DOF evaluation]

[0867] The focal length range formed by the range of ±10% (16.2 to 19.8 nm) of the 18 nm size in the LS pattern was determined as the depth of focus. The larger the value, the wider the depth of focus.

[0868] [Evaluation of Collapse Limit of Line Pattern]

[0869] The line size of each exposure dose at the optimal focal length of the LS pattern was measured at 10 locations in the longitudinal direction. The thinnest line size that could be obtained without collapse was defined as the collapse limit size. The smaller the value, the better the collapse limit.

[0870] [Table 3]

[0871]

[0872]

[0873] [Table 4]

[0874]

[0875] The results shown in Tables 3 and 4 demonstrate that the chemically amplified resist composition containing the quencher of the present invention exhibits good sensitivity and excellent EL, LWR, and DOF. Furthermore, the collapse threshold is low, demonstrating strong resistance to pattern collapse even in fine pattern formation. Therefore, the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[0876] [5]EUV lithography evaluation (2)

[0877] [Examples 4-1 to 4-30, Comparative Examples 3-1 to 3-20]

[0878] Each chemically amplified resist composition (R-1 to R-30, CR-1 to CR-20) was spin-coated onto a 20 nm thick Si substrate with a Shin-Etsu Chemical Co., Ltd. silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass). Prebaking was performed using a hot plate at 105°C for 60 seconds to produce a 50 nm thick resist film. The resist film was exposed using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, and a mask with a hole pattern with a 46 nm pitch and +20% deviation on the wafer). PEB was performed using a hot plate for 60 seconds at the temperatures listed in Tables 5 and 6, followed by development with a 2.38% by mass TMAH aqueous solution for 30 seconds to form a hole pattern with a size of 23 nm.

[0879] Using a CD-SEM (CG6300) manufactured by Hitachi Advanced Technologies Co., Ltd., the exposure dose when forming a hole with a size of 23 nm was measured and used as the sensitivity. Furthermore, the dimensions of 50 holes were measured at this time, and the value (3σ) tripled from the standard deviation (σ) calculated from the results was used as the dimension deviation (CDU). The results are shown in Tables 5 and 6.

[0880] [Table 5]

[0881]

[0882]

[0883] [Table 6]

[0884]

[0885] From the results shown in Tables 5 and 6, it was confirmed that the chemically amplified resist composition of the present invention had good sensitivity and excellent CDU.

Claims

An onium salt comprising an aromatic carboxylic acid anion having an iodine atom and a cyclic ether structure in a partial structure and an onium cation.

2. The onium salt according to claim 1, represented by the following formula (1); Wherein, n1 is 0 or 1; n2 is an integer from 1 to 4; n3 is an integer from 1 to 4; n4 is an integer from 0 to 3; but when n1 is 0, 2≤n2+n3+n4≤5, and when n1 is 1, 2≤n2+n3+n4≤7; W A is a group containing a cyclic ether structure having 2 to 10 carbon atoms; R 1 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 or 3, the multiple R 1 They may also be bonded to each other and to form a ring together with the carbon atoms on the aromatic ring to which they are bonded, and a portion of the -CH2- of the ring may also be substituted by -O- or -S-; L A and L B are each independently a single bond, an ether bond, a thioether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond, or a carbamate bond; X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain heteroatoms; Z + Onium cation.

3. The onium salt according to claim 2, wherein L A It is an ether bond or a thioether bond.

4. The onium salt according to claim 2, wherein W A It is an oxirane ring which may have a substituent, an oxetane ring which may have a substituent, a tetrahydrofuran ring which may have a substituent, or a tetrahydropyran ring which may have a substituent.

5. The onium salt according to claim 2, wherein Z + It is a sulfonium cation represented by the following formula (cation-1), an iodonium cation represented by the following formula (cation-2), or an ammonium cation represented by the following formula (cation-3); Where R ct1 ~R ct9 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 ~R ct3 Any two of them may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, R ct6 ~R ct9 Any two of them may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded. A quencher comprising the onium salt according to any one of claims 1 to 5. 7 . A chemically amplified resist composition comprising the quencher according to claim 6 .

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

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

10. The chemically amplified resist composition according to claim 8, wherein The base polymer comprises a repeating unit represented by the following formula (b1) or (b2); Where R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; Y 1 is a single bond or *-C(=O)-O-; * represents an atomic bond to a carbon atom of the main chain; R 21 A group having 1 to 20 carbon atoms, 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)-); R 22 is a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom; b is an integer from 1 to 4; c is an integer from 0 to 4; but 1≤b+c≤5.

11. The chemically amplified resist composition according to claim 8, wherein The base polymer comprises at least one selected from the group consisting of a repeating unit represented by the following formula (c1), a repeating unit represented by the following formula (c2), a repeating unit represented by the following formula (c3), and a repeating unit represented by the following formula (c4); Where R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; Z 1 is a single bond or a phenylene group which may have a substituent; Z 2 is a single bond, **-C(=O)-OZ 21 -, **-C(=O)-NH-Z 21 -or**-OZ 21 -;Z 21 An aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may also contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group; Z 3 is a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond; Z 4 is a single bond, an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may also contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group; Z 5 Each independently represents a single bond, and optionally substituted phenylene, naphthylene or *-C(=O)-OZ 51 -;Z 51 is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the aliphatic alkylene group may also contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or a lactone ring; Z 6 is a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond; Z 7 Each is independently a single bond, ***-Z 71 -C(=O)-O-、***-C(=O)-NH-Z 71 -or ***-OZ 71 -;Z 71 is an alkylene group having 1 to 20 carbon atoms which may also contain heteroatoms; Z 8 Each is independently a single bond, ****-Z 81 -C(=O)-O-、****-C(=O)-NH-Z 81 -or ****-OZ 81 -;Z 81 is an alkylene group having 1 to 20 carbon atoms which may also contain heteroatoms; Z 9 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 91 -, *-C(=O)-N(H)-Z 91 -or*-OZ 91 -;Z 91 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group; * indicates the atomic bond with the carbon atom of the main chain; ** indicates the atomic bond with Z 1 *** indicates atomic bond with Z 6 **** indicates the atomic bond with Z 7 atomic bonds; R 31 and R 32 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom; and R 31 and R 32 They may also bond to each other and form a ring together with the sulfur atom to which they are bonded; L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond, or a carbamate bond; Rf 1 and Rf 2 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Rf 3 and Rf 4 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Rf 5 and Rf 6 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; however, Rf 5 and Rf 6 They will not all be hydrogen atoms at the same time; M - It is a non-nucleophilic relative ion; A + is an onium cation; d is 0, 1, 2 or 3.

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

13. The chemically amplified resist composition according to claim 7, further comprising a photoacid generator that generates a strong acid.

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

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

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

17. The pattern forming method according to claim 16, wherein: The high-energy ray is KrF excimer laser, ArF excimer laser, electron beam or extreme ultraviolet ray with a wavelength of 3 to 15 nm.

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