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 invention provides a photolithography using high-energy rays. The present invention relates to an onium salt used in a chemically amplified resist composition having excellent solvent solubility, high sensitivity, high contrast, and excellent lithography performance such as LWR, CDU, MEF, EL, and DOF, a chemically amplified resist composition containing the onium salt as a photoacid generator, and a pattern forming method using the chemically amplified resist composition. The onium salt is represented by formula (1).

Description

Technical Field

[0001] This invention relates to onium salts, chemically amplified resist compositions, and patterning methods. Background Technology

[0002] In recent years, with the increasing integration and speed of LSI, there is a demand for miniaturized and regular patterns. As the next generation of microfabrication technology, far-ultraviolet lithography and extreme ultraviolet (EUV) lithography are considered promising.

[0003] ArF lithography, using an ArF excimer laser, was partially adopted starting with the fabrication of devices at the 130nm node and became the dominant lithography technology from the 90nm node onwards. As the next-generation lithography technology for the 45nm node, lithography using the 157nm F2 laser was initially considered promising, but development delays due to various problems were criticized. Therefore, ArF immersion lithography, which achieves high resolution by inserting a liquid with a higher refractive index than air (such as water, ethylene glycol, or glycerol) between the projection lens and the wafer, allows for the design of the numerical aperture (NA) of the projection lens to be greater than 1.0, and has rapidly developed (Non-Patent Document 1) and is now in the practical application stage. In this immersion lithography, a resist composition that is not easily dissolved in water is required.

[0004] In ArF lithography, to prevent the degradation of delicate and expensive optical system materials, a highly sensitive resist composition capable of achieving sufficient resolution with low exposure is required. The most common method to achieve this is to select components that are highly transparent at 193 nm. For example, regarding base polymers, polyacrylic acid and its derivatives, norcamphene-maleic anhydride alternating polymers, polynorcamphene, ring-opening shift polymers, and ring-opening shift polymer hydrides have been proposed, achieving some success in improving the transparency of the resin monomers.

[0005] In recent years, along with positive resists developed using alkaline aqueous solutions, negative resists developed using organic solvents have also attracted attention. To resolve extremely fine aperture patterns that cannot be achieved with positive toning through negative exposure, a high-resolution positive resist composition is used, and development with an organic solvent is employed to form a negative pattern. Furthermore, research has been conducted on achieving twice the resolution by combining alkaline aqueous solution development and organic solvent development. Known positive ArF resist compositions can be used as negative-tone development compositions using organic solvents, and pattern formation methods using these compositions are described in Patent Documents 1-3.

[0006] To adapt to the rapid miniaturization in recent years, the development of photoresist compositions has advanced alongside processing technologies. Various studies have been conducted on photoacid generators, typically using sulfonium salts composed of triphenylsulfonium cations and perfluoroalkyl sulfonate anions. However, perfluoroalkyl sulfonates, especially perfluorooctanoic acid (PFOS), which are the generated acids, have concerns regarding their poor biocompatibility, bioconcentration potential, and toxicological effects, leading to strict limitations in their application in photoresist compositions. Currently, photoacid generators that generate perfluorobutanesulfonate are used. However, when used in photoresist compositions, the generated acid diffuses significantly, making it difficult to achieve high resolution. To address this issue, various partially fluorinated alkyl sulfonates and their salts have been developed. For example, Patent Document 1, as background technology, discloses photoacid generators that generate α,α-difluoroalkyl sulfonate by exposure, specifically 1,1-difluoro-2-(1-naphthyl)ethanesulfonic acid di(4-tert-butylphenyl)monazine, and photoacid generators that generate α,α,β,β-tetrafluoroalkyl sulfonate. However, although they all reduce the fluorine substitution rate, they are insufficient from the perspective of environmental safety due to their lack of decomposable substituents such as ester structures. Consequently, there are limitations in the molecular design for changing the size of alkyl sulfonic acids. In addition, there are problems such as the high cost of starting materials containing fluorine atoms.

[0007] Furthermore, as circuit linewidths shrink, the contrast degradation caused by acid diffusion in the resist composition becomes more severe. This is because the pattern size approaches the acid diffusion length, increasing the dimensional offset on the wafer relative to the shielding dimensional offset (masking error factor (MEF)). This leads to reduced shielding fidelity and deterioration of pattern rectangularity. Therefore, to fully realize the benefits of shorter wavelengths and higher photoluminescence (NA) of the light source, it is necessary to increase the dissolution contrast or suppress acid diffusion more than known materials. As one improvement measure, lowering the baking temperature reduces acid diffusion, which can improve MEF, but inevitably leads to lower sensitivity.

[0008] Introducing bulky substituents and polar groups into photoacid generators is effective in suppressing acid diffusion. Patent Document 4 describes a photoacid generator containing 2-acyloxy-1,1,3,3,3-pentafluoropropane-1-sulfonic acid, which exhibits excellent solvent solubility and stability and allows for extensive molecular design. In particular, the photoacid generator containing 2-(1-adamantoxy)-1,1,3,3,3-pentafluoropropane-1-sulfonic acid with bulky substituents exhibits low acid diffusion. Furthermore, Patent Documents 5-7 describe photoacid generators incorporating condensed ring lactones, sulfonyl lactones, and thiolactones as polar groups. While some performance improvement has been confirmed through the acid diffusion suppression effect brought about by the introduction of polar groups, the control over the degree of acid diffusion remains insufficient. Considering factors such as MEF, pattern shape, and sensitivity, the photolithography performance is not satisfactory.

[0009] To suppress the diffusion of acid generated by photoacid generators, onium salts with a betaine structure containing both onium cation and anion sites within the same molecule have been proposed. Patent documents 8-10 describe betaine-type onium salts containing fluoroalkyl sulfonic acid anion and sulfonium cation sites, and their use in ArF and EUV lithography. Furthermore, Patent documents 11 and 12 propose polar-reversed betaine-type onium salts obtained by introducing acetal protecting groups into these betaine-type onium salts. While this improves lithography performance, there is still room for further improvement.

[0010] Iodine atoms exhibit very high absorption at the 13.5 nm EUV wavelength, confirming their ability to generate secondary electrons during exposure, thus gaining importance in EUV lithography. Patent documents 13 and 14 describe photoacid generators incorporating iodine atoms into anions, while patent document 15 describes a photoacid generator with polymerizable groups incorporating iodine atoms into anions. Patent document 16 describes a photoacid generator incorporating iodine atoms into both cations and anions. While this confirms some improvement in lithography performance, the low solubility of iodine atoms in organic solvents raises concerns about their precipitation. To meet the demands of further miniaturization, the development of new photoacid generators is crucial, with the aim of developing photoacid generators that offer excellent control over acid diffusion, superior solvent solubility, and effective suppression of pattern collapse.

[0011] Existing technical documents

[0012] Patent documents

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

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

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

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

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

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

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

[0020] [Patent Document 8] Japanese Patent No. 5387181

[0021] [Patent Document 9] Japanese Patent No. 5865725

[0022] [Patent Document 10] Japanese Patent No. 6237428

[0023] [Patent Document 11] Japanese Patent No. 6950357

[0024] [Patent Document 12] Japanese Patent No. 7111047

[0025] [Patent Document 13] Japanese Patent No. 6720926

[0026] [Patent Document 14] International Publication No. 2024 / 057701

[0027] [Patent Document 15] Japanese Patent No. 6973274

[0028] [Patent Document 16] Japanese Patent No. 7041204

[0029] Non-patent literature

[0030] [Non-patent literature 1] Journal of Photopolymer Science and Technology, Vol.17, No.4, pp.587-601 (2004) Summary of the Invention

[0031] [The problem the invention aims to solve]

[0032] In response to the increasing demand for high-resolution resist patterns in recent years, resist compositions using known onium salt-type photoacid generators cannot adequately suppress acid diffusion. As a result, photolithographic properties such as contrast, LWR, CDU, MEF, exposure margin (EL), and depth of focus (DOF) are degraded. Furthermore, during the formation of fine patterns, there is a problem of pattern collapse due to swelling.

[0033] The present invention was made in view of the above circumstances, and its object is to provide an ononium salt used in a chemical amplifying resist composition, particularly in optical lithography using high-energy rays such as KrF excimer lasers, ArF excimer lasers, electron beams (EB), and EUV, which has excellent solvent solubility, high sensitivity, high contrast, and excellent lithography performance such as LWR, CDU, MEF, EL, and DOF; a chemical amplifying resist composition containing the ononium salt as a photoacid generator; and a pattern formation method using the chemical amplifying resist composition.

[0034] [Methods used to solve problems]

[0035] To achieve the above objectives, the inventors conducted repeated and in-depth research and discovered that betaine-type onium salts, which have aromatic sulfonic acid anionic sites and sulfonium cation sites with iodine-substituted aromatic rings within the same molecule, exhibit excellent solvent solubility. Chemical amplification resist compositions using betaine-type onium salts as photoacid generators have high sensitivity and high contrast, and excellent photolithography performance in LWR, CDU, MEF, EL, and DOF formats. They are also extremely effective in suppressing pattern collapse during the formation of fine patterns, thus completing this invention.

[0036] That is, the following onium salt, chemically amplified resist composition and pattern formation method are provided.

[0037] 1. An onium salt, represented by the following formula (1),

[0038] [Chemistry 1]

[0039]

[0040] In the formula, n1 is 0 or 1, n2 is 1, 2, 3 or 4, n3 is 0, 1 or 2, but when n1 is 0, 1≤n2+n3≤4, when n1 is 1, 1≤n2+n3≤6, n4 is 0 or 1, and n5 is 0, 1, 2, 3 or 4.

[0041] R a The radical can be a halogen atom other than an iodine atom, a nitro group, a cyano group, a hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. When n3 is 2, there are 2 R radicals. a They can be the same or different, 2 Rs a They can bond to each other and form rings together with the carbon atoms they are bonded to.

[0042] R b The R group can be a halogen atom, nitro group, cyano group, hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms containing heteroatoms. When n5 is 2, 3, or 4, each R group... b They can be the same or different, multiple Rs b They can bond to each other and form rings together with the carbon atoms they are bonded to.

[0043] R 1 and R 2 Each is an independent hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. Additionally, R... 1 R 2 and S in the formula + Any two atoms in a bonded aromatic ring can bond to each other and form a ring together with the sulfur atoms they are bonded to.

[0044] L A and L B Each bond can be independently a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond.

[0045] X L1 It is a single bond, or may contain heteroatoms and a hydrocarbon group with 1 to 40 carbon atoms.

[0046] 2. Onium salts as in 1. are represented by the following formula (1A),

[0047] [Chemistry 2]

[0048]

[0049] In the formula, n1~n5, R a R b L A L B X L1 Same as above,

[0050] n6 can be 0 or 1, n7 can be 0, 1 or 2, n8 can be 0, 1, 2, 3 or 4, n9 can be 0 or 1, n10 can be 0, 1 or 2, and n11 can be 0, 1, 2, 3 or 4. However, when n6 is 0, 0 ≤ n7 + n8 ≤ 5; when n6 is 1, 0 ≤ n7 + n8 ≤ 7. Also, when n9 is 0, 0 ≤ n10 + n11 ≤ 5; when n9 is 1, 0 ≤ n10 + n11 ≤ 7.

[0051] R c The radical can be a halogen atom other than fluorine, a nitro group, a cyano group, a hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. When n7 is 2, there are 2 R radicals. c They can be the same or different, 2 Rs c They can bond to each other and form rings together with the carbon atoms they are bonded to.

[0052] R d The radical can be a halogen atom other than fluorine, a nitro group, a cyano group, a hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. When n10 is 2, there are 2 R radicals. d They can be the same or different, 2 Rs d They can bond to each other and form rings together with the carbon atoms they are bonded to.

[0053] R F1 and R F2Each R is independently a fluorine atom, a pentafluorosulfur group, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon sulfur group having 1 to 6 carbon atoms. When n8 is 2 or more, each R F1 They can be the same or different. When n11 is 2 or more, each R F2 They can be the same or different.

[0054] 3. The onium salts of 2. are represented by the following formula (1B),

[0055] [Chemistry 3]

[0056]

[0057] In the formula, n1~n11, R a R b R c R d R F1 R F2 and L A Same as above.

[0058] 4. A photoacid generator, comprising an onium salt of any one of 1. to 3.

[0059] 5. A chemically amplified resist composition comprising a photoacid generator as described in 4.

[0060] 6. The chemically amplified resist composition of 5. further contains a base polymer, the base polymer containing at least one repeating unit selected from the repeating units represented by formula (a1), formula (a2), and formula (a3) ​​below.

[0061] [Chemistry 4]

[0062]

[0063] In the formula, R A Each is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0064] X 1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -or *-C(=O)-NH-X 11 - The phenylene or naphthylene group may also be substituted by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group containing fluorine atoms with 1 to 10 carbon atoms, a saturated hydrocarbon oxygen group containing fluorine atoms with 1 to 10 carbon atoms, or a halogen atom. X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group having 1 to 10 carbon atoms. The saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring.

[0065] X2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-.

[0066] * indicates an atomic bond with a carbon atom in the main chain.

[0067] R 11 The radical can be a halogen atom, cyano group, hydroxyl group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon oxygen group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms containing heteroatoms. When a1 is 2, 3, or 4, each R... 11 They can be the same or different.

[0068] AL 1 and AL 2 Each is an independent acid-labile group.

[0069] a1 is 0, 1, 2, 3, or 4.

[0070] [Chemistry 5]

[0071]

[0072] In the formula, b1 is 0 or 1, and b2 is 0, 1, 2 or 3 when b1 is 0, and 0, 1, 2, 3, 4 or 5 when b1 is 1.

[0073] R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0074] X 3 These are single bonds, *-C(=O)-O-, or *-C(=O)-NH-, where * indicates an atomic bond with a carbon atom in the main chain.

[0075] X 4 It is a single bond, an aliphatic hydrocarbon group, carbonyl group, sulfonyl group, or a combination thereof, consisting of 1 to 4 carbon atoms.

[0076] X 5 and X 6 Each can be independently an oxygen atom or a sulfur atom, but X 4 and X 6 Bonded to adjacent carbon atoms of the aromatic ring,

[0077] R 12 and R 13 Each is an independent hydrocarbon group consisting of 1 to 20 carbon atoms, or may contain heteroatoms. Additionally, R... 12 and R 13 They can also bond to each other and form rings together with the carbon atoms they are bonded to.

[0078] R 14 It may contain halogen atoms, hydroxyl groups, cyano groups, nitro groups, or hydrocarbon groups with 1 to 20 carbon atoms containing heteroatoms; hydrocarbon oxy groups with 1 to 20 carbon atoms containing heteroatoms; hydrocarbon oxycarbonyl groups with 2 to 20 carbon atoms containing heteroatoms; or hydrocarbon thio groups with 1 to 20 carbon atoms containing heteroatoms, or -N(R) groups. 14A (R) 14B ), R 14A and R 14B Each is independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms; when b2 is 2 or more, each R 14 They can be the same or different, multiple Rs 14 They can bond to each other and form rings together with the carbon atoms of the aromatic rings they are bonded to.

[0079] 7. A chemically amplified resist composition as described in 6, wherein the base polymer comprises at least one repeating unit selected from repeating units represented by formula (b1) and repeating units represented by formula (b2).

[0080] [Chemistry 6]

[0081]

[0082] In the formula, R A Each is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0083] Y 1 It represents a single bond or *-C(=O)-O-, where * indicates an atomic bond with a carbon atom in the main chain.

[0084] R 21 It is a hydrogen atom, or a group containing at least one of the following structures with 1 to 20 carbon atoms: hydroxyl group (other than phenolic hydroxyl group), cyano group, carbonyl group, carboxyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulcinolone ring, and carboxylic anhydride (-C(=O)-OC(=O)-).

[0085] R 22 The group can be a halogen atom, hydroxyl group, carboxyl group, nitro group, cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon oxygen group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms containing heteroatoms. When c2 is 2, 3, or 4, each R... 22 They can be the same or different.

[0086] c1 can be 1, 2, 3 or 4, and c2 can be 0, 1, 2, 3 or 4, but 1≤c1+c2≤5.

[0087] 8. A chemically amplified resist composition as described in 6 or 7, wherein the base polymer comprises at least one repeating unit selected from the following formula (c1), repeating units represented by the following formula (c2), repeating units represented by the following formula (c3), repeating units represented by the following formula (c4), and repeating units represented by the following formula (c5).

[0088] [Chemistry 7]

[0089]

[0090] In the formula, d1 and d2 are each independently 0, 1, 2, or 3; e1 is 0 or 1; e2 is 0, 1, 2, 3, or 4; and e3 is 0, 1, 2, 3, or 4. However, when e1 is 0, 0 ≤ e2 + e3 ≤ 4; and when e1 is 1, 0 ≤ e2 + e3 ≤ 6.

[0091] R A Each is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0092] Z 1 It can be a single bond or may have substituents, phenylene

[0093] Z 2 Indicates a single bond, **-C(=O)-OZ 21 -、**-C(=O)-NH-Z 21 -or**-OZ 21 -, Z 21 It is a divalent group consisting of an aliphatic hydrocarbon group, a phenylene group, or a combination thereof, having 1 to 6 carbon atoms, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group.

[0094] Z 3 The bonds can be single bonds, ether bonds, ester bonds, amide bonds, sulfonate bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds.

[0095] Z 4 It is a single bond, or 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.

[0096] Z 5 Each can be a single bond, or may have substituents such as phenylene, naphthylene, or *-C(=O)-OZ. 51 -, Z 51 It is an aliphatic hydrocarbon group, phenylene, or naphthylene group having 1 to 10 carbon atoms. The aliphatic hydrocarbon group may also contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or a lactone ring.

[0097] Z 6The bonds can be single bonds, ether bonds, ester bonds, amide bonds, sulfonate bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds.

[0098] Z 7 Each is independently a single bond, ***-Z 71 -C(=O)-O-、***-C(=O)-NH-Z 71 -or ***-OZ 71 -, Z 71 It may also contain a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms.

[0099] Z 8 Each is independently a single key, ****-Z 81 -C(=O)-O-、****-C(=O)-NH-Z 81 -or ****-OZ 81 -, Z 81 It may also contain a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms.

[0100] Z 9 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, fluorinated phenylene, or phenylene substituted with trifluoromethyl, having 1 to 6 carbon atoms, and may contain a carbonyl group, ester bond, ether bond, or hydroxyl group.

[0101] * indicates an atomic bond with a carbon atom in the main chain, ** indicates an atomic bond with a Z atom. 1 atomic bonds, *** indicates the relationship with Z 6 atomic bonds, **** indicates the relationship with Z 7 atomic bonds,

[0102] L 1 The bonds can be single bonds, ether bonds, ester bonds, carbonyl groups, sulfonate bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds.

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

[0104] 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.

[0105] Rf 5 and Rf 6Each is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; however, all Rf 5 and Rf 6 They are not both hydrogen atoms.

[0106] Rf 7 It is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated alkylthio group having 1 to 6 carbon atoms.

[0107] R 31 and R 32 Each can be an independent hydrocarbon group with 1 to 20 carbon atoms, and may also contain heteroatoms. Additionally, R... 31 and R 32 They can also bond to each other and form rings together with the sulfur atoms they are bonded to.

[0108] R 33 When e3 is 2, 3, or 4, each R... 33 They can be the same or different, multiple Rs 33 They can bond to each other and form rings together with the carbon atoms they are bonded to.

[0109] M - It is a non-nucleophilic relative ion.

[0110] Z + It is a ium cation.

[0111] 9. Chemically amplified resist compositions, such as those in any of 5 to 8, further contain organic solvents.

[0112] 10. Chemically amplified resist compositions such as those in 5. to 9, further contain quenching agents.

[0113] 11. The chemically amplified resist composition of any one of 5 to 10, further contains a photoacid generating agent other than the photoacid generating agent of 4.

[0114] 12. Any chemically amplified resist composition as described in any of items 5 to 11, further contains a surfactant.

[0115] 13. A method for forming a pattern, comprising the following steps:

[0116] A resist film is formed on a substrate using a chemically amplified resist composition as described in any of 5 to 12; the resist film is exposed to high-energy rays; and the exposed resist film is developed using a developer.

[0117] 14. The pattern forming method as in 13, wherein the high-energy ray is a KrF excimer laser, an ArF excimer laser, an electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

[0118] [The effects of the invention]

[0119] When patterning is performed using a chemically amplified resist composition containing the onium salt of the present invention as a photoacid generator, it is possible to form resist patterns with high contrast and good sensitivity, excellent photolithography performance such as LWR, CDU, MEF, EL, and DOF, and suppressed pattern collapse. Detailed Implementation

[0120] [Salt]

[0121] The onium salt of the present invention is represented by the following formula (1).

[0122] [Chemistry 8]

[0123]

[0124] In formula (1), n1 is 0 or 1. When n1 is 0, it is a benzene ring; when n1 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with n1 of 0 is more ideal. n2 is 1, 2, 3, or 4. From the viewpoint of solvent solubility, n2 is preferably 1, 2, or 3. n3 is 0, 1, or 2. From the viewpoint of raw material supply, n3 is preferably 0 or 1. However, when n1 is 0, 1 ≤ n2 + n3 ≤ 4; when n1 is 1, 1 ≤ n2 + n3 ≤ 6. n4 is 0 or 1. When n4 is 0, it is a benzene ring; when n4 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with n4 of 0 is more ideal. n5 is 0, 1, 2, 3, or 4. From the viewpoint of raw material supply, n5 is preferably 0, 1, 2, or 3, and 0 or 1 is even better.

[0125] In equation (1), R aThe halogen atom can be a halogen atom other than iodine, a nitro group, a cyano group, a hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms containing heteroatoms. Examples of halogen atoms other than iodine include fluorine, chlorine, and bromine atoms, with fluorine being preferred. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples include: alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl; cyclic saturated hydrocarbon groups with 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornel, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups with 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these. Among these, aryl is preferred. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, a portion of the -CH2- group in the aforementioned hydrocarbon groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, groups such as hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonyl lactone ring, carboxylic anhydride (-C(=O)-OC(=O)-), and haloalkyl groups can be present. When n3 is 2, each R... a They can be the same or different. Additionally, when n3 is 2, there are 2 R... a They can bond to each other and form rings together with the carbon atoms they are bonded to. Preferably, these rings are 5- to 8-membered rings.

[0126] In equation (1), R b The halogen atom can be a nitro group, a cyano group, a hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine, with fluorine or iodine atoms being preferred. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples include R... a The groups represented by the hydrocarbon groups are the same as those shown. When n5 is 2, 3, or 4, each R b They can be the same or different. Additionally, when n₄ is 2, 3, or 4, multiple R₁ can... bThey can bond to each other and form rings together with the carbon atoms they are bonded to. Preferably, these rings are 5- to 8-membered rings.

[0127] In equation (1), R 1 and R 2 Each is an independent hydrocarbon group consisting of halogen atoms or may contain heteroatoms, and has 1 to 30 carbon atoms.

[0128] R 1 and R 2 Specific examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms.

[0129] R 1 and R 2 The represented hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples include alkyl groups with 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornel, and adamantyl; alkenyl groups with 2 to 30 carbon atoms such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups with 3 to 30 carbon atoms such as cyclohexenyl; aryl groups with 6 to 30 carbon atoms such as phenyl, naphthyl, and thiophene; aralkyl groups with 7 to 30 carbon atoms such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these, but aryl is preferred. In addition, some or all of the hydrogen atoms in the above-mentioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. A portion of the -CH2- in the above-mentioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it can 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, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0130] Additionally, R 1 R 2 and S in the formula + Any two atoms in a bonded aromatic ring can bond to each other and together with the sulfur atoms they are bonded to form a ring. Specific examples of the aforementioned ring structure include the structures shown below.

[0131] [Chemistry 9]

[0132]

[0133] In the formula, the dashed line represents the intersection with R. ct3 Atomic bonds.

[0134] In equation (1), LA and L B Each bond can be independently a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond. Among these, single bonds, ether bonds, or ester bonds are preferred.

[0135] In equation (1), X L1 It is a hydrocarbon group with 1 to 40 carbon atoms, which may be a single bond or contain heteroatoms. The aforementioned hydrocarbon group can be straight-chain, branched, or cyclic, and specific examples include alkyldiyl, divalent saturated cyclic hydrocarbon group, aryl, etc. Examples of heteroatoms include oxygen, nitrogen, sulfur, etc.

[0136] X L1 The indicated group may contain a heteroatom and have 1 to 40 carbon atoms, preferably the group shown below. Furthermore, in the following formulas, * indicates a group related to L. A and L B The key.

[0137] [Chemistry 10]

[0138]

[0139] [Chemistry 11]

[0140]

[0141] [Chemistry 12]

[0142]

[0143] [Chemistry 13]

[0144]

[0145] Among them, X L -0~X L -22, X L -29~X L -34 and X L -47~X L -58 is better.

[0146] The onium salt shown in formula (1) is preferably the onium salt shown in formula (1A) below.

[0147] [Chemistry 14]

[0148]

[0149] In the formula, n1~n5, R a R b L A L B X L1 Same as above.

[0150] In formula (1A), n6 is 0 or 1. When n6 is 0, it is a benzene ring; when n6 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with n6 of 0 is preferred. n7 is 0, 1, or 2. From the viewpoint of raw material supply, n7 is preferably 0 or 1. n8 is 0, 1, 2, 3, or 4. From the viewpoint of ensuring solvent solubility and reactivity, n8 is preferably 1, 2, or 3. However, when n6 is 0, 0 ≤ n7 + n8 ≤ 5; when n6 is 1, 0 ≤ n7 + n8 ≤ 7. n9 is 0 or 1. When n9 is 0, it is a benzene ring; when n9 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with n9 of 0 is preferred. n10 is 0, 1, or 2. From the viewpoint of raw material supply, n10 is preferably 0 or 1. n11 is 0, 1, 2, 3, or 4. From the viewpoint of ensuring solvent solubility and reactivity, n11 is preferably 1, 2, or 3. However, when n9 is 0, 0 ≤ n10 + n11 ≤ 5, and when n9 is 1, 0 ≤ n10 + n11 ≤ 7.

[0151] In equation (1A), R c The halogen atom can be a halogen atom other than fluorine, a nitro group, a cyano group, a hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. Examples of halogen atoms other than fluorine include chlorine atoms, bromine atoms, and iodine atoms, with iodine atoms being preferred. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples can be listed and described in the explanation of formula (1) regarding R. a The groups represented by the hydrocarbon groups are the same groups. When n7 is 2, each R c They can be the same or different. Additionally, when n7 is 2, there are 2 R... c They can bond to each other and form rings together with the carbon atoms they are bonded to. Preferably, these rings are 5- to 8-membered rings.

[0152] In equation (1A), R d The halogen atom can be a nitro group, cyano group, hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms containing heteroatoms. Examples of halogen atoms other than fluorine atoms include chlorine atoms, bromine atoms, and iodine atoms, with iodine atoms being preferred. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. As a specific example, R is mentioned in the description of formula (1). a The groups represented by the hydrocarbon groups are the same groups. When n10 is 2, each R d They can be the same or different. Additionally, when n10 is 2, there are 2 R... dThey can bond to each other and form rings together with the carbon atoms they are bonded to. Preferably, these rings are 5- to 8-membered rings.

[0153] In equation (1A), R F1 and R F2 Each is independently a fluorine atom, a pentafluorothio group, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms. As R F1 and R F2 Preferably, the substituent is a fluorine atom, pentafluorothio, trifluoromethyl, difluoromethyl, trifluoromethoxy, difluoromethoxy, trifluoromethylthio, or difluoromethylthio, and more preferably a fluorine atom, pentafluorothio, trifluoromethyl, or trifluoromethoxy. By utilizing these substituents containing or having a fluorine atom, the acid strength is increased through electron-withdrawing effects, thus facilitating the deprotection reactions of unstable acid groups such as tertiary esters or tertiary ethers described later. When n10 is 2, 3, or 4, each R... F1 They can be the same or different. When n11 is 2, 3, or 4, each R... F2 They can be the same or different.

[0154] Furthermore, when n6 or n9 is 0 (i.e., a benzene ring), R is bonded to each aromatic ring. F1 and R F2 In the case of S bonded to sulfonium cations + The bonded carbon atom is preferably located in the meta position. By bonding at this position, the electron-withdrawing effect from the fluorine atom takes effect effectively, reducing the LUMO in the frontier molecular orbital theory of the sulfonium cation, thereby promoting the decomposition of the sulfonium cation and effectively generating acid, thus increasing sensitivity.

[0155] The onium salt represented by formula (1A) is preferably the onium salt represented by formula (1B) below.

[0156] [Chemistry 15]

[0157]

[0158] In the formula, n1~n11, R a R b R c R d R F1 R F2 and L A Same as above.

[0159] Specific examples of onium salts represented by equation (1) can be listed below, but are not limited to these.

[0160] [Chemistry 16]

[0161]

[0162] [Chemistry 17]

[0163]

[0164] [Chemistry 18]

[0165]

[0166] [Chemistry 19]

[0167]

[0168] [Chemistry 20]

[0169]

[0170] [Chemistry 21]

[0171]

[0172] [Chemistry 22]

[0173]

[0174] [Chemistry 23]

[0175]

[0176] [Chemistry 24]

[0177]

[0178] [Chemistry 25]

[0179]

[0180] [Chemistry 26]

[0181]

[0182] [Chemistry 27]

[0183]

[0184] [Chemistry 28]

[0185]

[0186] [Chemistry 29]

[0187]

[0188] [Chemistry 30]

[0189]

[0190] [Chemistry 31]

[0191]

[0192] [Chemistry 32]

[0193]

[0194] [Chemistry 33]

[0195]

[0196] [Chemistry 34]

[0197]

[0198] [Chemistry 35]

[0199]

[0200] [Chemistry 36]

[0201]

[0202] [Chemistry 37]

[0203]

[0204] [Chemistry 38]

[0205]

[0206] [Chemistry 39]

[0207]

[0208] [Chemistry 40]

[0209]

[0210] [Chemistry 41]

[0211]

[0212] [Chemistry 42]

[0213]

[0214] [Chemistry 43]

[0215]

[0216] [Chemistry 44]

[0217]

[0218] [Chemistry 45]

[0219]

[0220] [Chemistry 46]

[0221]

[0222] [Chemistry 47]

[0223]

[0224] [Chemistry 48]

[0225]

[0226] [Chemistry 49]

[0227]

[0228] [Transformation 50]

[0229]

[0230] [Chemistry 51]

[0231]

[0232] [Chemistry 52]

[0233]

[0234] [Chemistry 53]

[0235]

[0236] [Chemistry 54]

[0237]

[0238] [Chemistry 55]

[0239]

[0240] [Chemistry 56]

[0241]

[0242] [Chemistry 57]

[0243]

[0244] [Chem.58]

[0245]

[0246] [Chemistry 59]

[0247]

[0248] [Transformation 60]

[0249]

[0250] [Chemistry 61]

[0251]

[0252] [Chemistry 62]

[0253]

[0254] [Chemistry 63]

[0255]

[0256] [Chemistry 64]

[0257]

[0258] [Chemistry 65]

[0259]

[0260] The onium salt of the present invention can be synthesized using known methods. Specifically, it can be synthesized using the corresponding aromatic sulfonic acid anion, according to the methods described in Japanese Patent Nos. 6237428

[0084] to

[0088] . Furthermore, the above-described manufacturing method is merely one example, and the manufacturing method of the onium salt of the present invention is not limited thereto.

[0261] As a structural feature of the onium salt of the present invention, a betaine-type structure can be cited as an example, in which an aromatic sulfonic acid anion site having an iodine-substituted aromatic ring is bonded to a sulfonium cation site via a linking group. Since the iodine atom is a high molecular weight element, it can be used as a group to inhibit acid diffusion. Furthermore, particularly in 13.5 nm EUV lithography, the EUV absorption of the iodine atom is very large, thus generating secondary electrons from the iodine atom during exposure. Furthermore, due to its moderate electron-withdrawing property, the acidity of the generated acid is increased, promoting the deprotection reaction of the base polymer. In addition, the S in the sulfonium cation... +When the aromatic ring of the bond has a fluorine atom or a substituent containing a fluorine atom, the solvent solubility of the onium salt itself can be improved. Furthermore, the electron-withdrawing effect reduces the frontier molecular orbital (LUMO) of the sulfonium cation site, making it easier to accept electrons. Since the onium salt molecule contains an iodine atom, the spatial distance between the sulfonium cation site and the iodine atom becomes closer, and the resulting secondary electrons are accepted by the LUMO, thereby decomposing the cation site and effectively generating acid. In addition, since the onium salt of the present invention has a betaine-type structure, it is foreseeable that the onium salts will approach each other through electrostatic interactions, resulting in a structure with a molecular weight that is approximately twice that of the original. This suppresses excessive acid diffusion. Due to their synergistic effect, the resist composition containing the onium salt of the present invention exhibits good solvent solubility, high sensitivity, and low acid diffusion, thus enabling the formation of excellent line pattern LWR, hole pattern CDU, and pattern collapse resistant patterns, making it suitable for forming fine patterns.

[0262] [Photoacid Generator]

[0263] The above-mentioned onium salts are suitable for use as photoacid generators.

[0264] [Chemical amplification resist composition]

[0265] The chemically amplified resist composition of the present invention comprises (A) a photoacid generator consisting of an onium salt represented by formula (1).

[0266] In the chemically amplified resist composition of the present invention, the content of the photoacid generator composed of the ononium salt represented by formula (1) in component (A) is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 30 parts by mass, relative to 80 parts by mass of the base polymer described later. If the content of component (A) is within the above range, the sensitivity and resolution are good, and there is no concern about the generation of impurities after development or stripping of the resist film, which is therefore ideal. The photoacid generator (A) can be used alone or in combination of two or more.

[0267] [(B) Basic Polymer]

[0268] The chemically amplified resist composition of the present invention may contain a base polymer as component (B). Examples of base polymers (B) include polymers containing repeating units represented by formula (a1) (hereinafter also referred to as repeating unit a1.) or repeating units represented by formula (a2) (hereinafter also referred to as repeating unit a2.).

[0269] [Chemistry 66]

[0270]

[0271] In equations (a1) and (a2), R AEach can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0272] In equation (a1), X 1 Indicates single bond, phenylene, naphthylene, *-C(=O)-OX 11 -or *-C(=O)-NH-X 11 - The phenylene or naphthylene group may also be substituted by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group containing fluorine atoms with 1 to 10 carbon atoms, a saturated hydrocarbon oxygen group containing fluorine atoms with 1 to 10 carbon atoms, or a halogen atom. X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group having 1 to 10 carbon atoms. The saturated hydrocarbon group may also contain hydroxyl groups, ether bonds, ester bonds, or lactone rings. * indicates an atomic bond with a carbon atom in the main chain.

[0273] In equation (a2), X 2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-.

[0274] * indicates an atomic bond with a carbon atom in the main chain. R 11 It may contain a halogen atom, a cyano group, a hydroxyl group, a nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms. a1 is 0, 1, 2, 3, or 4, preferably 0 or 1.

[0275] In equations (a1) and (a2), AL 1 and AL 2 Each of these groups is an acid-indestructible group. Specific examples of the aforementioned acid-indestructible groups include those described in Japanese Patent Application Publication Nos. 2013-80033 and 2013-83821.

[0276] Typically, specific examples of the aforementioned acid-instable groups can be represented by the following formulas (AL-3) to (AL-5).

[0277] [Chemistry 67]

[0278]

[0279] In the formula, * represents an atomic bond.

[0280] In equations (AL-3) and (AL-4), R L11 and R L12Each hydrocarbon group is independently composed of 1 to 40 carbon atoms and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The aforementioned hydrocarbon groups may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Preferably, the hydrocarbon group is composed of 1 to 20 carbon atoms.

[0281] In formula (AL-3), a2 is an integer from 0 to 10, preferably 1, 2, 3, 4 or 5.

[0282] In equation (AL-4), R L13 and R L14 Each group is independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The aforementioned hydrocarbon groups may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Preferably, the hydrocarbon group has 1 to 20 carbon atoms. Additionally, R... L12 R L13 and R L14 Any two atoms in the ring can bond to each other and together with the carbon atoms they are bonded to, or carbon atoms and oxygen atoms, form a ring with 3 to 20 carbon atoms. Preferably, the ring has 4 to 16 carbon atoms, and more preferably, it is an alicyclic ring.

[0283] In equation (AL-5), R L15 R L16 and R L17 Each hydrocarbon group is independently a hydrocarbon group having 1 to 20 carbon atoms and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The aforementioned hydrocarbon groups may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Preferably, the hydrocarbon group has 1 to 20 carbon atoms. Additionally, R... L15 R L16 and R L17 Any two of the atoms in the ring can bond to each other and together with the carbon atoms they are bonded to form a ring with 3 to 20 carbon atoms. Preferably, the ring has 4 to 16 carbon atoms, and more preferably, it is an alicyclic ring.

[0284] As specific examples of repeating unit a1, the following repeating units can be cited, but are not limited to these. Furthermore, in the following formula, R... A and AL 1 Same as above.

[0285] [Chemistry 68]

[0286]

[0287] [Chemistry 69]

[0288]

[0289] [Chemistry 70]

[0290]

[0291] [Chemistry 71]

[0292]

[0293] As specific examples of repeating unit a2, the following repeating units can be cited, but are not limited to these. Furthermore, in the following formula, R... A and AL 2 Same as above.

[0294] [Chemistry 72]

[0295]

[0296] [Chemistry 73]

[0297]

[0298] [Chemistry 74]

[0299]

[0300] The aforementioned basic polymer may contain repeating units represented by the following formula (a3) ​​(hereinafter also referred to as repeating unit a3).

[0301] [Chemistry 75]

[0302]

[0303] In formula (a3), b1 is 0 or 1. When b1 is 0, it is a benzene ring; when b1 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with b1 of 0 is preferred. b2 is 0, 1, 2, or 3 when b1 is 0, and 0, 1, 2, 3, 4, or 5 when b1 is 1. From the viewpoint of raw material supply, b2 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0304] In equation (a3), R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, hydrogen atoms and methyl groups are preferred, and hydrogen atoms are even more preferred.

[0305] In equation (a3), X 3 It is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond with a carbon atom in the main chain. Among these, a single bond, *-C(=O)-O-, and even more preferably a single bond are preferred.

[0306] In equation (a3), X 4The group is a single bond, an aliphatic alkylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a combination thereof. Among these, from the viewpoint of raw material supply, a single bond, a carbonyl group, or a sulfonyl group is preferred, and from the viewpoint of the polar group generated after the reaction, a single bond or a carbonyl group is more preferred.

[0307] In equation (a3), X 5 and X 6 Each can be independently an oxygen atom or a sulfur atom. However, X 4 and X 6 It is bonded to an adjacent carbon atom in the aromatic ring. X 5 and X 6 They can be the same or different; from a reactivity point of view, X 5 and X 6 Ideally, all atoms should be oxygen atoms.

[0308] In equation (a3), R 12 and R 13 Each hydrocarbon group consists of 1 to 20 carbon atoms, which may be hydrogen atoms or may contain heteroatoms. The aforementioned hydrocarbon groups may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples include alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl; cyclic saturated hydrocarbon groups with 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornel, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups with 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them. In addition, some or all of the hydrogen atoms in the above-mentioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. A portion of the -CH2- in the above-mentioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it can contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0309] Additionally, R 12 and R 13These atoms can bond to each other to form rings with the carbon atoms they are bonded to. Specific examples of rings formed in this way include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, and adamantane rings. Furthermore, some or all of the hydrogen atoms in the above rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, a portion of the -CH2- group in the above rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the rings may also contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentalide rings, carboxylic anhydrides (-C(=O)-OC(=O)-), and haloalkyl groups.

[0310] In equation (a3), R 14 This indicates a halogen atom, hydroxyl group, cyano group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms; a hydrocarbon oxygen group with 1 to 20 carbon atoms that may contain heteroatoms; a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms that may contain heteroatoms; or a hydrocarbon thio group or -N(R) group with 1 to 20 carbon atoms. 14A (R) 14B R 14A and R 14B Each halogen atom is independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. The aforementioned halogen atom is preferably a fluorine, chlorine, bromine, or iodine atom, more preferably a fluorine or iodine atom. The hydrocarbon group, as well as the hydrocarbon group of the aforementioned hydrocarbon group, hydrocarbon oxy group, hydrocarbon oxycarbonyl group, and hydrocarbon thio group, can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples can be given and described with respect to R. 12 and R 13 The groups exemplified by the hydrocarbon group are the same groups. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and a portion of the -CH2- group in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, groups such as hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulopentalide ring, carboxylic anhydride (-C(=O)-OC(=O)-), and haloalkyl groups can be included. When b2 is 2 or more, each R... 14 They can be the same or different.

[0311] Additionally, when b2 is 2 or more, multiple R 14These rings can bond to each other and form rings together with the carbon atoms of the aromatic rings they are bonded to. Specific examples of rings formed in this way include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, and adamantane rings. Furthermore, some or all of the hydrogen atoms in the above rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. A portion of the -CH2- group in the above rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the rings may also contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentalide rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0312] As specific examples of repeating unit a3, the following repeating units can be cited, but are not limited to these. Furthermore, in the following formula, R... A As above, Me is methyl. Furthermore, the bonding positions of the various substituents on the aromatic ring can be interchanged.

[0313] [Chemistry 76]

[0314]

[0315] [Chemistry 77]

[0316]

[0317] [Chemistry 78]

[0318]

[0319] [Chemistry 79]

[0320]

[0321] [Chemistry 80]

[0322]

[0323] [Chemistry 81]

[0324]

[0325] [Chemistry 82]

[0326]

[0327] [Chemistry 83]

[0328]

[0329] [Chemistry 84]

[0330]

[0331] [Chemistry 85]

[0332]

[0333] [Chemistry 86]

[0334]

[0335] [Chemistry 87]

[0336]

[0337] [Chemistry 88]

[0338]

[0339] [Chemistry 89]

[0340]

[0341] [Chemistry 90]

[0342]

[0343] [Chemistry 91]

[0344]

[0345] [Chemistry 92]

[0346]

[0347] [Chemistry 93]

[0348]

[0349] [Chemistry 94]

[0350]

[0351] [Chem. 95]

[0352]

[0353] [Chemistry 96]

[0354]

[0355] [Chemistry 97]

[0356]

[0357] [Chem. 98]

[0358]

[0359] [Chemistry 99]

[0360]

[0361] [Chemistry 100]

[0362]

[0363] [Chemistry 101]

[0364]

[0365] [Chemistry 102]

[0366]

[0367] [Chemistry 103]

[0368]

[0369] [Chemistry 104]

[0370]

[0371] [Chemistry 105]

[0372]

[0373] [Chemistry 106]

[0374]

[0375] [Chemistry 107]

[0376]

[0377] [Chemistry 108]

[0378]

[0379] [Chemistry 109]

[0380]

[0381] [Chemical 110]

[0382]

[0383] [Chemistry 111]

[0384]

[0385] [Chemistry 112]

[0386]

[0387] [Chemistry 113]

[0388]

[0389] [Chemistry 114]

[0390]

[0391] [Chemistry 115]

[0392]

[0393] [Chemistry 116]

[0394]

[0395] [Chemistry 117]

[0396]

[0397] [Chemistry 118]

[0398]

[0399] [Chemistry 119]

[0400]

[0401] [Chemistry 120]

[0402]

[0403] [Chemistry 121]

[0404]

[0405] [Chemistry 122]

[0406]

[0407] [Chemistry 123]

[0408]

[0409] [Chemistry 124]

[0410]

[0411] [Chemistry 125]

[0412]

[0413] The aforementioned base polymer preferably further comprises at least one selected from repeating units represented by formula (b1) below (hereinafter also referred to as repeating unit b1.) and repeating units represented by formula (b2) below (hereinafter also referred to as repeating unit b2.).

[0414] [Chemistry 126]

[0415]

[0416] In equations (b1) and (b2), R A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 It represents a single bond or *-C(=O)-O-. * indicates an atomic bond with a carbon atom in the main chain. R 21 It is a hydrogen atom, or a group having at least one structure containing 1 to 20 carbon atoms selected from hydroxyl groups other than phenolic hydroxyl groups, cyano groups, carbonyl groups, carboxyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulcinolone rings, and carboxylic anhydrides (-C(=O)-OC(=O)-). R 22 The radical can be a halogen atom, hydroxyl group, carboxyl group, nitro group, cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms. c1 is 1, 2, 3, or 4. c2 is 0, 1, 2, 3, or 4. However, 1 ≤ c1 + c2 ≤ 5. When c2 is 2, 3, or 4, each R 22 They can be the same or different.

[0417] As specific examples of repeating unit b1, the following repeating units can be cited, but are not limited to these. Furthermore, in the following formula, R... A Same as above.

[0418] [Chemistry 127]

[0419]

[0420] [Chemistry 128]

[0421]

[0422] [Chemistry 129]

[0423]

[0424] [Chemistry 130]

[0425]

[0426] [Chemistry 131]

[0427]

[0428] [Chemistry 132]

[0429]

[0430] [Chemistry 133]

[0431]

[0432] [Chemistry 134]

[0433]

[0434] [Chemistry 135]

[0435]

[0436] [Chemistry 136]

[0437]

[0438] [Chemistry 137]

[0439]

[0440] [Chemistry 138]

[0441]

[0442] [Chemistry 139]

[0443]

[0444] [Chemistry 140]

[0445]

[0446] [Chemistry 141]

[0447]

[0448] [Chemistry 142]

[0449]

[0450] As specific examples of repeating unit b2, the following repeating units can be cited, but are not limited to these. Furthermore, in the following formula, R... A Same as above.

[0451] [Chemistry 143]

[0452]

[0453] [Chemistry 144]

[0454]

[0455] [Chemistry 145]

[0456]

[0457] [Chemistry 146]

[0458]

[0459] [Chemistry 147]

[0460]

[0461] As repeating units b1 or b2, in ArF lithography, repeating units with lactone rings as polar groups are particularly preferred, while in KrF lithography, EB lithography and EUV lithography, repeating units with phenolic sites are more preferred.

[0462] The aforementioned base polymer may further comprise at least one selected from the following formula (c1) (hereinafter also referred to as repeating unit c1.), the following formula (c2) (hereinafter also referred to as repeating unit c2.), the following formula (c3) (hereinafter also referred to as repeating unit c3.), the following formula (c4) (hereinafter also referred to as repeating unit c4.), and the following formula (c5) (hereinafter also referred to as repeating unit c5.).

[0463] [Chemistry 148]

[0464]

[0465] In equations (c1) to (c5), R A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 It is a single bond or may have substituents. Z 2 For single bonds, **-C(=O)-OZ 21 -、**-C(=O)-NH-Z 21 -or**-OZ 21 -. Z 21 It is a divalent group consisting of an aliphatic hydrocarbon group, a phenylene group, or a combination thereof, having 1 to 6 carbon atoms, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 3 It can be a single bond, ether bond, ester bond, amide bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. 4It is a single bond, or 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 can be a single bond, or may have substituents such as phenylene, naphthylene, or *-C(=O)-OZ. 51 -. Z 51 It is an aliphatic alkylene group, phenylene group, or naphthylene group having 1 to 10 carbon atoms. This aliphatic alkylene group may also contain a halogen atom, hydroxyl group, ether bond, ester bond, or lactone ring. 6 It can be a single bond, ether bond, ester bond, amide bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. 7 Each is independently a single bond, ***-Z 71 -C(=O)-O-、***-C(=O)-NH-Z 71 -or ***-OZ 71 -. Z 71 It can also contain heteroatoms and is a hydrocarbon group with 1 to 20 carbon atoms. Z 8 Each is independently a single key, ****-Z 81 -C(=O)-O-、****-C(=O)-NH-Z 81 -or ****-OZ 81 -. Z 81 It can also contain heteroatoms and is a hydrocarbon group with 1 to 20 carbon atoms. Z 9 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, fluorinated phenylene, or phenylene substituted with trifluoromethyl, having 1 to 6 carbon atoms, and may contain a carbonyl group, ester bond, ether bond, or hydroxyl group. * indicates an atomic bond with a carbon atom in the main chain. ** indicates an atomic bond with Z. 1 Atomic bonds. *** indicates the relationship with Z. 6 Atomic bonds. **** indicates the relationship with Z. 7 Atomic bonds.

[0466] Z 21 Z 51 and Z 91The aliphatic alkylene group can be any of the following: straight-chain, branched, or cyclic. Specific examples include alkyl alkylene groups such as methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-2,2-diyl, butane-1,1-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-2,3-diyl, butane-1,4-diyl, 1,1-dimethylethane-1,2-diyl, pentane-1,5-diyl, 2-methylbutane-1,2-diyl, and hexane-1,6-diyl; cycloalkyl alkylene groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining them.

[0467] Z 71 and Z 81 The heteroatomic alkyl group represented may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples include the groups shown below, but are not limited to these.

[0468] [Chemistry 149]

[0469]

[0470] In the formula, the dashed lines represent atomic bonds.

[0471] In equation (c1), R 31 and R 32Each of the aforementioned hydrocarbon groups is independently a hydrocarbon group with 1 to 20 carbon atoms, and may also contain heteroatoms. The aforementioned hydrocarbon groups may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples include alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups with 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norcamphenyl, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups with 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups with 6 to 20 carbon atoms, such as phenyl, naphthyl, and thiophene; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them, but aryl is preferred. In addition, some or all of the hydrogen atoms in the above-mentioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. A portion of the -CH2- in the above-mentioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it can contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0472] Additionally, R 31 and R 32 They can bond to each other and form rings together with the sulfur atoms they are bonded to. Specific examples of the aforementioned rings include rings as shown in the following formula.

[0473] [Chemistry 150]

[0474]

[0475] In the formula, the dashed line represents the intersection with Z. 4 Atomic bonds.

[0476] Specific examples of cations that are repeating unit c1 include the cations shown below, but are not limited to these. Furthermore, in the following formula, R... A Same as above.

[0477] [Chemistry 151]

[0478]

[0479] [Chemistry 152]

[0480]

[0481] [Chemistry 153]

[0482]

[0483] [Chemistry 154]

[0484]

[0485] [Chemistry 155]

[0486]

[0487] [Chemistry 156]

[0488]

[0489] [Chemistry 157]

[0490]

[0491] [Chemistry 158]

[0492]

[0493] [Chemistry 159]

[0494]

[0495] [Chemistry 160]

[0496]

[0497] In equation (c1), M - The ion is a non-nucleophilic relative ion. Preferably, the non-nucleophilic relative ion is a halide ion, a sulfonic acid anion, an imide acid anion, or a methyl acid anion. Specific examples of halide ions include chloride ions and bromide ions. Specific examples of sulfonic acid anions (sulfonate ions) include fluoroalkyl sulfonate ions such as trifluoromethanesulfonate ion, 1,1,1-trifluoroethanesulfonate ion, and nonafluorobutanesulfonate ion; aryl sulfonate ions such as toluenesulfonate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, and 1,2,3,4,5-pentafluorobenzenesulfonate ion; and alkyl sulfonate ions such as methanesulfonate ion and butanesulfonate ion. Specific examples of imide acid anions (imide ions) include bis(trifluoromethanesulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, and bis(perfluorobutylsulfonyl)imide ion. Specific examples of the aforementioned methylated acid anions (methylated ions) include tris(trifluoromethanesulfonyl) methylated ions and tris(perfluoroethylsulfonyl) methylated ions.

[0498] Other examples of the aforementioned non-nucleophilic relative ions include anions represented by any of the formulas (c1-1) to (c1-4) below.

[0499] [Chemistry 161]

[0500]

[0501] In equation (c1-1), R fa It is a hydrocarbon group with 1 to 40 carbon atoms, which may contain fluorine atoms or heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. As a specific example, R in the following formula (c1-1-1) can be cited. fa1 The hydrocarbon group is the same group as the exemplified group.

[0502] The anion represented by formula (c1-1) is preferably the anion represented by the following formula (c1-1-1).

[0503] [Chemistry 162]

[0504]

[0505] In equation (c-1-1), Q 1 and Q 2 Each atom is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, but to improve solvent solubility, at least one atom is preferably a trifluoromethyl group. m is 0, 1, 2, 3, or 4, and particularly preferably 1. R fa1 The hydrocarbon group may contain heteroatoms and has 1 to 35 carbon atoms. The aforementioned heteroatoms are preferably oxygen, nitrogen, sulfur, or halogen atoms, and more preferably oxygen. From the viewpoint of obtaining high resolution in the formation of fine patterns, the hydrocarbon group has 6 to 30 carbon atoms.

[0506] In equation (c-1-1), R fa1 The hydrocarbon groups represented by carbon numbers 1 to 35 can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples include alkyl groups with 1 to 35 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecanyl, and eicosyl; cyclic saturated hydrocarbon groups with 3 to 35 carbon atoms, such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norcamphenyl, norcamphenylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated aliphatic hydrocarbon groups with 2 to 35 carbon atoms, such as 2-propenyl and 3-cyclohexenyl; aryl groups with 6 to 35 carbon atoms, such as phenyl, 1-naphthyl, 2-naphthyl, and 9-fluorenyl; aralkyl groups with 7 to 35 carbon atoms, such as benzyl and diphenylmethyl; and groups obtained by combining them.

[0507] Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, a portion of the -CH2- group in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, it can contain hydroxyl, fluorine, chlorine, bromine, iodine, cyano, nitro, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulopentalide ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc. Specific examples of hydrocarbon groups containing heteroatoms include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamoxymethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, 3-oxocyclohexyl, etc.

[0508] In equation (c-1-1), L a1 The bonds can be single bonds, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, or carbamate bonds. From a synthetic point of view, ether bonds or ester bonds are preferred, and ester bonds are even more preferred.

[0509] Specific examples of anions represented by formula (c1-1) can be given as shown below, but are not limited to these. Furthermore, in the following formula, Q... 1 As above, Ac is an acetyl group.

[0510] [Chemistry 163]

[0511]

[0512] [Chemistry 164]

[0513]

[0514] [Chemistry 165]

[0515]

[0516] [Chemistry 166]

[0517]

[0518] [Chemistry 167]

[0519]

[0520] [Chemistry 168]

[0521]

[0522] [Chemistry 169]

[0523]

[0524] [Chemistry 170]

[0525]

[0526] [Chemistry 171]

[0527]

[0528] [Chemistry 172]

[0529]

[0530] In equation (c1-2), R fb1 and R fb2 Each is independently a fluorine atom or a hydrocarbon group with 1 to 40 carbon atoms, which may contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. As a specific example, R in formula (c1-1-1) can be cited. fa1 The hydrocarbon group represented is the same group as the exemplified group. R fb1 and R fb2 Preferably, it is a fluorine atom or a straight-chain fluorinated alkyl group having 1 to 4 carbon atoms. Additionally, R... fb1 and R fb2 They can also bond to each other and to the groups they are bonded to (-CF2-SO2-N). - -SO2-CF2-) together form a ring, in which case, as R fb1 and R fb2 The groups obtained by mutual bonding are preferably fluorinated ethylidene or fluorinated propylene.

[0531] In equation (c1-3), R fc1 R fc2 and R fc3 Each is independently a fluorine atom or a hydrocarbon group with 1 to 40 carbon atoms, which may contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. As a specific example, R in formula (c1-1-1) can be cited. fa1 The hydrocarbon group represented is the same group as the exemplified group. R fc1 R fc2 and R fc3 Preferably, it is a fluorine atom or a straight-chain fluorinated alkyl group having 1 to 4 carbon atoms. Additionally, R... fc1 and R fc2 They can also bond to each other and to the groups they are bonded to (-CF2-SO2-C). - -SO2-CF2-) together form a ring, in which case, R fc1 and R fc2 The groups obtained by mutual bonding are preferably fluorinated ethylidene or fluorinated propylene.

[0532] In equation (c1-4), R fd It can be a hydrocarbon group with 1 to 40 carbon atoms, which may also contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. As a specific example, R in formula (c1-1-1) can be cited. fa1 The hydrocarbon group is the same group as the exemplified group.

[0533] As specific examples of anions represented by formula (c1-4), the following anions can be cited, but are not limited to these.

[0534] [Chemistry 173]

[0535]

[0536] [Chemistry 174]

[0537]

[0538] Examples of the aforementioned non-nucleophilic relative ions include anions having an aromatic ring substituted with iodine or bromine atoms. Specific examples of such anions include the anions represented by the following formulas (c1-5).

[0539] [Chemistry 175]

[0540]

[0541] In equation (c1-5), x is 1, 2, or 3. y is 1, 2, 3, 4, or 5. z is 0, 1, 2, or 3. However, 1 ≤ y + z ≤ 5. y is preferably 1, 2, or 3, more preferably 2 or 3. z is preferably 0, 1, or 2.

[0542] In equation (c1-5), X BI When x and / or y are 2 or more, they can be the same or different from each other.

[0543] In equation (c1-5), L 11 It is a saturated hydrocarbon group with 1 to 6 carbon atoms, which can be a single bond, ether bond, or ester bond, or may contain an ether bond or ester bond. The above-mentioned saturated hydrocarbon group can be any of the following: straight-chain, branched, or cyclic.

[0544] In equation (c1-5), L 12 When x is 1, it is a single bond or a divalent linker with 1 to 20 carbon atoms; when x is 2 or 3, it is a (x+1) valent linker with 1 to 20 carbon atoms. This linker may contain oxygen, sulfur, or nitrogen atoms.

[0545] In equation (c1-5), R feThis represents a hydroxyl group, carboxyl group, fluorine atom, chlorine atom, bromine atom, or amino group, or may contain a fluorine atom, chlorine atom, bromine atom, hydroxyl group, amino group, or ether bond of a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon oxygen group having 1 to 20 carbon atoms, a hydrocarbon carbonyl group having 2 to 20 carbon atoms, a hydrocarbon carbonyl group having 2 to 20 carbon atoms, or a hydrocarbon sulfonyl oxygen group having 1 to 20 carbon atoms, 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 is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. R feC It is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxygen group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl oxygen group having 2 to 6 carbon atoms. R 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 contain a halogen atom, a hydroxyl group, a saturated alkyloxy group having 1 to 6 carbon atoms, a saturated alkylcarbonyl group having 2 to 6 carbon atoms, or a saturated alkylcarbonyloxy 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, alkyloxy group, alkylcarbonyl group, alkyloxycarbonyl group, alkylcarbonyloxy group, and alkylsulfonyloxy group may be straight-chain, branched, or cyclic. When x and / or z is 2 or more, each R fe They can be the same or different.

[0546] Among them, as R fe hydroxyl group, -N(R) feC )-C(=O)-R feD -N(R) feC )-C(=O)-OR feD Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, and methoxy groups are preferred.

[0547] In equation (c1-5), Rf 11 ~Rf 14 Each is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, with at least one of them being a fluorine atom or a trifluoromethyl group. Additionally, Rf 11 and Rf 12 They can combine to form carbonyl groups. Specifically, Rf... 13 and Rf 14 Ideally, all atoms should be fluorine atoms.

[0548] Specific examples of anions represented by formula (c1-5) can be given as shown below, but are not limited to these. Furthermore, in the following formulas, X... BI Same as above.

[0549] [Chemistry 176]

[0550]

[0551] [Chemistry 177]

[0552]

[0553] [Chemistry 178]

[0554]

[0555] [Chemistry 179]

[0556]

[0557] [Chemistry 180]

[0558]

[0559] [Chemistry 181]

[0560]

[0561] [Chemistry 182]

[0562]

[0563] [Chemistry 183]

[0564]

[0565] [Chemistry 184]

[0566]

[0567] [Chemistry 185]

[0568]

[0569] [Chemistry 186]

[0570]

[0571] [Chemistry 187]

[0572]

[0573] [Chemistry 188]

[0574]

[0575] [Chemistry 189]

[0576]

[0577] [Chemistry 190]

[0578]

[0579] [Chemistry 191]

[0580]

[0581] [Chemistry 192]

[0582]

[0583] [Chemistry 193]

[0584]

[0585] [Chemistry 194]

[0586]

[0587] [Chemistry 195]

[0588]

[0589] [Chemistry 196]

[0590]

[0591] [Chemistry 197]

[0592]

[0593] [Chemistry 198]

[0594]

[0595] As the aforementioned non-nucleophilic relative ion, the following can also be used: the fluorobenzenesulfonic acid anion bonded to an aromatic group containing an iodine atom as described in Japanese Patent No. 6648726; the anion with a mechanism of decomposition by acid as described in International Publication No. 2021 / 200056 and Japanese Patent Application Publication No. 2021-70692; the anion with a cyclic ether group as described in Japanese Patent Application Publication No. 2018-180525 and Japanese Patent Application Publication No. 2021-35935; and the anion as described in Japanese Patent Application Publication No. 2018-92159.

[0596] As the aforementioned non-nucleophilic relative ions, the following can also be used: the anion of a bulky benzenesulfonic acid derivative without fluorine atoms as described in Japanese Patent Application Publication No. 2006-276759, Japanese Patent Application Publication No. 2015-117200, Japanese Patent Application Publication No. 2016-65016 and Japanese Patent Application Publication No. 2019-202974; the benzenesulfonic acid anion without fluorine atoms bonded to an aromatic group containing an iodine atom as described in Japanese Patent No. 6645464; and the alkylsulfonic acid anion.

[0597] As the aforementioned non-nucleophilic relative ions, the anions of disulfonic acid described in Japanese Patent Application Publication No. 2015-206932, the anions of sulfonamides and sulfonylimides with one side being sulfonic acid and the other side being different, as described in International Publication No. 2020 / 158366, and the anions of sulfonic acid and carboxylic acid as described in Japanese Patent Application Publication No. 2015-24989, can also be used.

[0598] In equations (c2) and (c3), d1 and d2 are each independently 0, 1, 2 or 3, preferably 1.

[0599] In equation (c4), e1 is 0 or 1. e2 is 0, 1, 2, 3 or 4. e3 is 0, 1, 2, 3 or 4. However, when e1 is 0, 0 ≤ e2 + e3 ≤ 4, and when e1 is 1, 0 ≤ e2 + e3 ≤ 6.

[0600] In equations (c2), (c3), and (c4), L 1 The bonds can be single bonds, ether bonds, ester bonds, carbonyl groups, sulfonate bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. From a synthetic point of view, ether bonds, ester bonds, and carbonyl groups are preferred, with ester bonds and carbonyl groups being even more preferred.

[0601] In equation (c2), Rf 1 and Rf 2 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. However, Rf 1 and Rf 2 To increase the acid strength of the generated acid, it is preferable that all atoms are fluorine 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. Among these, Rf is used to improve solvent solubility. 3 and Rf 4 At least one of them is preferably trifluoromethyl.

[0602] In equation (c3), Rf 5 and Rf 6 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. However, all Rf 5 and Rf6 They are not all hydrogen atoms at the same time. Among these, Rf is used to improve solvent solubility. 5 and Rf 6 At least one of them is preferably trifluoromethyl.

[0603] In equation (c4), Rf 7 It is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated alkylthio group having 1 to 6 carbon atoms. Rf 7 Preferably, it is a fluorine atom, trifluoromethyl, difluoromethyl, trifluoromethoxy, difluoromethoxy, trifluoromethylthio, or difluoromethylthio; more preferably, it is a fluorine atom, trifluoromethyl, or trifluoromethoxy. When f is 2, 3, or 4, each Rf 7 They can be the same or different.

[0604] In equation (c4), R 33 It is a halogen atom other than fluorine or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. As a specific example, for instance, R is described in the explanation of formula (1). 1 The groups represented by the hydrocarbon groups are the same as those shown, but are not limited to these. Additionally, when e3 is 2, 3, or 4, each R... 33 They can be the same or different.

[0605] Additionally, when e3 is 2, 3, or 4, multiple R 33 These atoms can bond to each other and form rings together with the carbon atoms they are bonded to. Specific examples of rings formed in this way include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, and adamantane rings. Furthermore, some or all of the hydrogen atoms in the above rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, a portion of the -CH2- group in the above rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the rings may also contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentalide rings, carboxylic anhydrides (-C(=O)-OC(=O)-), and haloalkyl groups.

[0606] Specific examples of anions for the repeating unit c2 include the anions shown below, but are not limited to these. Furthermore, R in the following formula... A As above, Me is a methyl group.

[0607] [Chemistry 199]

[0608]

[0609] [Chem.200]

[0610]

[0611] [Chemical Engineering 201]

[0612]

[0613] [Chemical Engineering 202]

[0614]

[0615] [Chemical Engineering 203]

[0616]

[0617] [Chemical 204]

[0618]

[0619] [Chemical Engineering 205]

[0620]

[0621] [Chemical Engineering 206]

[0622]

[0623] [Chemical 207]

[0624]

[0625] [Chemical Engineering 208]

[0626]

[0627] [Chemical Engineering 209]

[0628]

[0629] [Chemical 210]

[0630]

[0631] [Chemistry 211]

[0632]

[0633] Specific examples of the anion in repeating unit c3 can be listed below, but are not limited to these. Furthermore, in the following formula, R... A Same as above.

[0634] [Chemistry 212]

[0635]

[0636] [Chemistry 213]

[0637]

[0638] [Chemistry 214]

[0639]

[0640] [Chemical 215]

[0641]

[0642] [Chemistry 216]

[0643]

[0644] [Chemistry 217]

[0645]

[0646] [Chemistry 218]

[0647]

[0648] [Chemistry 219]

[0649]

[0650] [Chem.220]

[0651]

[0652] [Chemistry 221]

[0653]

[0654] [Chemistry 222]

[0655]

[0656] Specific examples of anions that are repeating unit c4 can be listed below, but are not limited to these. Furthermore, in the following formula, R... A Same as above.

[0657] [Chemistry 223]

[0658]

[0659] [Chemistry 224]

[0660]

[0661] [Chemistry 225]

[0662]

[0663] [Chemistry 226]

[0664]

[0665] [Chemistry 227]

[0666]

[0667] [Chemistry 228]

[0668]

[0669] [Chemistry 229]

[0670]

[0671] [Chemistry 230]

[0672]

[0673] [Chemistry 231]

[0674]

[0675] [Chemistry 232]

[0676]

[0677] [Chemistry 233]

[0678]

[0679] [Chemistry 234]

[0680]

[0681] [Chemistry 235]

[0682]

[0683] [Chemistry 236]

[0684]

[0685] [Chemistry 237]

[0686]

[0687] [Chemistry 238]

[0688]

[0689] [Chemistry 239]

[0690]

[0691] Specific examples of anions for the repeating unit c5 include the anions shown below, but are not limited to these. Furthermore, in the following formula, R... A Same as above.

[0692] [Chemistry 240]

[0693]

[0694] In equations (c2) to (c5), Z + The cation is a sulfonium cation. Preferably, the sulfonium cation is represented by formula (Z-1) or the sulfonium cation is represented by formula (Z-2).

[0695] [Chemistry 241]

[0696]

[0697] In equations (Z-1) and (Z-2), R ct1 ~R ct5 Each is an independent hydrocarbon group consisting of halogen atoms or may contain heteroatoms, and has 1 to 30 carbon atoms.

[0698] R ct1 ~R ct5 Specific examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms.

[0699] R ct1 ~R ct5 The represented hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples include alkyl groups with 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornel, and adamantyl; alkenyl groups with 2 to 30 carbon atoms such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups with 3 to 30 carbon atoms such as cyclohexenyl; aryl groups with 6 to 30 carbon atoms such as phenyl, naphthyl, and thiophene; aralkyl groups with 7 to 30 carbon atoms such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these, but aryl is preferred. In addition, some or all of the hydrogen atoms in the above-mentioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. A portion of the -CH2- in the above-mentioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it can 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, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0700] Additionally, R ct1 and R ct2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to. In this case, specific examples of the aforementioned ring structures can be listed, such as the structures shown in the following formulas.

[0701] [Chemistry 242]

[0702]

[0703] In the formula, the dashed line represents the intersection with R. ct3 Atomic bonds.

[0704] Specific examples of sulfonium cations represented by formula (Z-1) include those described in Japanese Patent Application Publication No. 2024-003744 in

[0102] to

[0125] , but are not limited to these.

[0705] As a specific example of a citric acid represented by formula (Z-2), the citric acid described in Japanese Patent Application Publication No. 2024-000259

[0181] can be cited, but it is not limited to these.

[0706] Z + The onium cation represented is preferably a sulfonium cation represented by the following formula (Z-3).

[0707] [Chemistry 243]

[0708]

[0709] In formula (Z-3), m1 is 0 or 1. When m1 is 0, it is a benzene ring; when m1 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, it is preferable that m1 is 0, which represents a benzene ring. m2 is 0 or 1. When m2 is 0, it is a benzene ring; when m2 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, it is preferable that m2 is 0, which represents a benzene ring. m3 is 0 or 1. When m3 is 0, it is a benzene ring; when m3 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, it is preferable that m3 is 0, which represents a benzene ring.

[0710] In formula (Z-3), m4 is 0, 1, 2, 3, or 4. The more iodine atoms in the cationic structure, the higher the absorption of EUV, but the solvent solubility is insufficient, and it may precipitate in the resist composition. Therefore, m4 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0711] In formula (Z-3), m5 is 0, 1, 2, 3, or 4. From the viewpoint of raw material supply, m5 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. m6 is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material supply, m6 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. m7 is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material supply, m7 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0712] In formula (Z-3), m8 is 0, 1, or 2. From the perspective of raw material supply, m8 is preferably 0 or 1. m9 is 0, 1, or 2. From the perspective of raw material supply, m9 is preferably 0 or 1. m10 is 0, 1, or 2. From the perspective of raw material supply, m10 is preferably 0 or 1.

[0713] In formula (Z-3), m11 is 0 or 1. When m11 is 0, it is a benzene ring; when m11 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, it is preferable to have a benzene ring with m11 of 0.

[0714] In formula (Z-3), m12 is 0, 1, 2, 3, or 4. The more iodine atoms in the cationic structure, the higher the absorption of EUV, but the solvent solubility becomes insufficient, and it may precipitate in the resist composition. Therefore, m12 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0715] In formula (Z-3), m13 is 0, 1, or 2. From the viewpoint of raw material supply, m13 is preferably 0 or 1. m14 is 0, 1, or 2. From the viewpoint of synthesis, m14 is preferably 0 or 1.

[0716] However, when m1 is 0, 0 ≤ m6 + m9 ≤ 4; when m1 is 1, 0 ≤ m6 + m9 ≤ 6. When m2 is 0, 0 ≤ m7 + m10 ≤ 4; when m2 is 1, 0 ≤ m7 + m10 ≤ 6. When m3 is 0, 0 ≤ m4 + m5 + m8 + m14 ≤ 4; when m3 is 1, 1 ≤ m4 + m5 + m8 + m14 ≤ 6. When m11 is 0, 0 ≤ m12 + m13 ≤ 4; when m11 is 1, 0 ≤ m12 + m13 ≤ 6. Additionally, m4 + m12 ≥ 1.

[0717] In equation (Z-3), R F3 ~R F5 Each R is independently a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms. Among these, trifluoromethyl, trifluoromethoxy, and trifluorothiomethoxy are preferred. When m5 is 2 or more, each R... F3 They can be the same or different. When m6 is 2 or more, each R F4 They can be the same or different. When m7 is 2 or more, each RF5 They can be the same as or different from each other.

[0718] In equation (Z-3), R ct6 ~R ct9 The halogen atom other than iodine and fluorine atoms, nitro, cyano, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms, an alkyloxy group with 1 to 20 carbon atoms that may contain heteroatoms, or an alkylthio group with 1 to 20 carbon atoms that may contain heteroatoms. The hydrocarbon group, alkyloxy group, and alkylthio group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. As a specific example, R can be listed and described in the explanation of formula (1). 1 The groups exemplified by the hydrocarbon group are the same groups. In addition, part or all of the hydrogen atoms in the hydrocarbon group, alkyloxy group, and alkylsulfonyl group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. Part of the -CH2- of the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it can contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulfonolactone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0719] Additionally, when m8 is 2, there are 2 R... ct6 They can be the same or different, 2 Rs ct6 They can bond to each other and form rings together with the carbon atoms they are bonded to. When m9 is 2, there are 2 R atoms. ct7 They can be the same or different, 2 Rs ct7 They can bond to each other and form rings together with the carbon atoms they are bonded to. When m10 is 2, there are 2 R atoms. ct8 They can be the same or different, 2 Rs ct8 They can bond to each other and form rings together with the carbon atoms they are bonded to. When m13 is 2, there are 2 R atoms. ct9 They can be the same or different, 2 Rs ct9 These atoms can bond to each other and form rings together with the carbon atoms they are bonded to. Specific examples of rings formed in this way include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, and adamantane rings. Furthermore, some or all of the hydrogen atoms in the above rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, a portion of the -CH2- group in the above rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the rings may also contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentalide rings, carboxylic anhydrides (-C(=O)-OC(=O)-), and haloalkyl groups.

[0720] In addition, the S in the sulfonium cation shown in formula (Z-3) + Directly bonded aromatic rings can bond with each other and S + Together they form a ring. Specific examples of the aforementioned ring structure can be given by structures such as those shown in the following formula.

[0721] [Chemistry 244]

[0722]

[0723] In the formula, the dashed lines represent atomic bonds.

[0724] In equation (Z-3), L C and L D Each bond can be independently a single bond, ether bond, ester bond, amide bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. Among them, L... C Preferably, it is a single bond, ether bond, ester bond, or sulfonate bond; more preferably, it is an ester bond or sulfonate bond. D Preferred to be a single bond, ether bond, or ester bond, with a single bond being more preferred.

[0725] In equation (Z-3), X L2 It is a single-bonded or heteroatom-containing hydrocarbon group with 1 to 40 carbon atoms. The aforementioned hydrocarbon group can be straight-chain, branched, or cyclic, and specific examples include alkyldiyl, cyclic saturated hydrocarbon group, aryl, etc. Specific examples of the aforementioned heteroatom include oxygen atoms, nitrogen atoms, sulfur atoms, etc.

[0726] X L2 Specific examples of hydrocarbon groups containing 1 to 40 carbon atoms, which may also contain heteroatoms, can be listed in the description of formula (1) regarding X. L1 The examples shown may include alkylene groups with 1 to 40 carbon atoms containing heteroatoms, but are not limited to these groups. L -0~X L X in -58 L2 X L -0~X L -22, X L -29~X L -34 and X L -47~X L -58 is better.

[0727] The sulfonium cation represented by formula (Z-3) is preferably the sulfonium cation represented by formula (Z-3-1) below.

[0728] [Chemistry 245]

[0729]

[0730] In the formula, m4~m10, m12~m14, R F3 ~R F5 R ct6 ~R ct9 L C L D and X L Same as above.

[0731] The sulfonium cation represented by formula (Z-3-1) is preferably the sulfonium cation represented by formula (Z-3-2) below.

[0732] [Chemistry 246]

[0733]

[0734] In the formula, m4~m10, R F3 ~R F5 and R ct6 ~R ct8 Same as above.

[0735] Specific examples of sulfonium cations represented by formula (Z-3) are shown below, but are not limited to these. Furthermore, in the following formulas, Me is a methyl group.

[0736] [Chemistry 247]

[0737]

[0738] [Chemistry 248]

[0739]

[0740] [Chemistry 249]

[0741]

[0742] [Chemistry 250]

[0743]

[0744] [Chemistry 251]

[0745]

[0746] [Chemistry 252]

[0747]

[0748] [Chemistry 253]

[0749]

[0750] [Chemistry 254]

[0751]

[0752] [Chemistry 255]

[0753]

[0754] [Chemistry 256]

[0755]

[0756] [Chemistry 257]

[0757]

[0758] [Chemistry 258]

[0759]

[0760] [Chemistry 259]

[0761]

[0762] [Chemistry 260]

[0763]

[0764] [Chemistry 261]

[0765]

[0766] [Chemistry 262]

[0767]

[0768] [Chemistry 263]

[0769]

[0770] [Chemistry 264]

[0771]

[0772] [Chemistry 265]

[0773]

[0774] [Chemistry 266]

[0775]

[0776] [Chemistry 267]

[0777]

[0778] [Chemistry 268]

[0779]

[0780] [Chemistry 269]

[0781]

[0782] [Chemistry 270]

[0783]

[0784] [Chemistry 271]

[0785]

[0786] [Chemistry 272]

[0787]

[0788] [Chemistry 273]

[0789]

[0790] [Chemistry 274]

[0791]

[0792] As specific structures of repeating units c1 to c5, any combination of the above-mentioned anions and cations can be cited.

[0793] Of the repeating units c1 to c5, repeating units c2 to c5 are preferred from the viewpoint of controlling acid diffusion; repeating units c2, c4 and c5 are further preferred from the viewpoint of the acid strength of the generated acid; and repeating unit c2 is more preferred from the viewpoint of solvent solubility.

[0794] The aforementioned base polymer may further include repeating units (hereinafter also referred to as repeating units d) having a structure in which hydroxyl groups are protected by acid-indestructible groups. As a repeating unit d, there is no particular limitation as long as it has a structure in which one or more hydroxyl groups are protected and the protecting group is decomposed by the action of an acid to generate hydroxyl groups, but it is preferably a repeating unit shown in the following formula (d1).

[0795] [Chemistry 275]

[0796]

[0797] In equation (d1), R A Same as above. R 41 It can also contain heteroatoms and be a (f+1) valence hydrocarbon group with 1 to 30 carbon atoms. R 42 It is an acid-labile group. f can be 1, 2, 3, or 4.

[0798] In equation (d1), R42 The acid-labile group shown may be any group that is deprotected by the action of an acid to generate a hydroxyl group. R 42 The structure of R is not particularly limited, and preferably is an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (d2), etc., and particularly preferably an alkoxymethyl group represented by the following formula (d2).

[0799] [Chemical formula 276]

[0800]

[0801] In the formula, * represents an atomic bond. R 43 is a hydrocarbon group having 1 to 15 carbon atoms.

[0802] R 42 Specific examples of the acid-labile group represented, the alkoxymethyl group represented by the formula (d2), and the repeating unit d may include the same substances as those exemplified in the description of the repeating unit d described in Japanese Patent Application Laid-Open No. 2020-111564.

[0803] The aforementioned base polymer may further contain a repeating unit e derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or their derivatives. Specific examples of the monomer that provides the repeating unit e may include the monomers shown below, but are not limited thereto.

[0804] [Chemical formula 277]

[0805]

[0806] The above base polymer may further contain a repeating unit f derived from indan, vinylpyridine or vinylcarbazole.

[0807] In the polymer of the present invention, the content ratios of the repeating units a1, a2, a3, b1, b2, c1 to c5, d, e and f are preferably 0 < a1 ≤ 0.8, 0 ≤ a2 ≤ 0.8, 0 ≤ a3 ≤ 0.6, 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 ≤ c5 ≤ 0.4, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.3 and 0 ≤ f ≤ 0.3, more preferably 0 < a1 ≤ 0.7, 0 ≤ a2 ≤ 0.7, 0 ≤ a3 ≤ 0.5, 0 ≤ b1 ≤ 0.5, 0 ≤ b2 ≤ 0.5, 0 ≤ c1 ≤ 0.3, 0 ≤ c2 ≤ 0.3, 0 ≤ c3 ≤ 0.3, 0 ≤ c4 ≤ 0.3, 0 ≤ c5 ≤ 0.3, 0 ≤ d ≤ 0.3, 0 ≤ e ≤ 0.3 and 0 ≤ f ≤ 0.3. However, a1 + a2 + a3 + b1 + b2 + c1 + c2 + c3 + c4 + d + e + f ≤ 1.0.

[0808] The weight-average molecular weight (Mw) of the aforementioned polymer is preferably between 1,000 and 500,000, more preferably between 3,000 and 100,000. If Mw is within this range, sufficient etch resistance can be obtained, and there is no concern about reduced resolution due to the inability to ensure the difference in dissolution rates before and after exposure. Furthermore, in this invention, Mw is a polystyrene equivalent value obtained by gel permeation chromatography (GPC) using THF or N,N-dimethylformamide (DMF) as a solvent.

[0809] Furthermore, regarding the aforementioned molecular weight distribution (Mw / Mn) of the polymer, as the pattern regularity becomes finer, the influence of Mw / Mn tends to increase. Therefore, in order to obtain a resist composition suitable for fine pattern sizes, Mw / Mn is preferably a narrow dispersion of 1.0 to 2.0. If it is within the above range, there are fewer low-molecular-weight and high-molecular-weight polymers, and after exposure, there will be no risk of foreign matter being seen on the pattern or the shape of the pattern deteriorating.

[0810] To synthesize the above polymer, for example, the monomer that provides the repeating unit can be polymerized by adding a free radical polymerization initiator to an organic solvent and heating.

[0811] Specific examples of organic solvents used in 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 polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl 2,2-azobis(2-methylpropionic acid), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of these initiators added relative to the total amount of monomers to be polymerized is preferably 0.01 to 25 mol%. 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 viewpoint of production efficiency, more preferably 2 to 12 hours.

[0812] The polymerization initiator described above can be added to the monomer solution and supplied to the reactor, or the initiator solution can be prepared separately from the monomer solution and supplied to the reactor independently. Since polymerization may occur during standby time due to free radicals generated from the initiator, resulting in ultra-high molecular weight polymers, from a quality management perspective, it is preferable to prepare the monomer solution and initiator solution independently and add them dropwise. Acid-labile groups can be directly used from groups introduced into the monomer, or they can be protected or partially protected after polymerization. Furthermore, to adjust the molecular weight, known chain transfer agents such as dodecyl mercaptan or 2-mercaptoethanol can be used in conjunction. In this case, the amount of these chain transfer agents added relative to the total amount of monomers to be polymerized is preferably 0.01 to 20 mol%.

[0813] In the case of monomers containing hydroxyl groups, the hydroxyl groups can be replaced with acetal groups such as ethoxyethoxy that are easily deprotected by acids during polymerization, and deprotection can be carried out using weak acids and water after polymerization. Alternatively, they can be replaced with acetyl, formyl, trimethylacetyl, etc. beforehand, and alkaline hydrolysis can be carried out after polymerization.

[0814] In the case of copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene can be polymerized with other monomers in an organic solvent by adding a free radical polymerization initiator and heating. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene can be used, and after polymerization, the acetoxy groups can be deprotected by alkaline hydrolysis to produce polyhydroxystyrene or hydroxyvinylnaphthalene.

[0815] Ammonia, triethylamine, etc., can be used as the base during alkaline hydrolysis. The preferred reaction temperature is -20 to 100°C, more preferably 0 to 60°C. The preferred reaction time is 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0816] Furthermore, the amount of each monomer in the above monomer solution can be appropriately set, for example, in a manner that forms a preferred content ratio for the above repeating units.

[0817] For the polymer obtained by the above manufacturing method, the reaction solution obtained by the polymerization reaction can be used as the final product, or the powder obtained by purification steps such as adding the polymer solution to a poor solvent and then reprecipitating the powder can be used as the final product. From the point of view of work efficiency and quality stabilization, it is preferable to use the polymer solution obtained by dissolving the powder obtained by the purification step in a solvent as the final product.

[0818] Specific examples of solvents used at this time include ketones such as cyclohexanone and methyl-2-n-pentyl ketone as described in Japanese Patent Application Publication No. 2008-111103

[0144] to

[0145] ; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; and propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethyl ether. Ethers such as dimethyl glycol ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate (EL), ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as GBL; 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 their mixed solvents.

[0819] In the above polymer solution, the polymer concentration is preferably 0.01–30% by mass, more preferably 0.1–20% by mass.

[0820] The above-mentioned reaction solution or polymer solution is preferably filtered. By filtering, foreign matter and gel that may cause defects can be removed, which is effective in stabilizing the quality.

[0821] Filter materials used in the aforementioned filtration processes include fluorocarbon, cellulose, nylon, polyester, and hydrocarbon-based filters. In the filtration step involving the resist composition, filters made of fluorocarbon (such as Teflon, a registered trademark), polyethylene, polypropylene, or nylon are preferred. The filter pore size can be appropriately selected based on the target cleanliness level, preferably below 100 nm, and more preferably below 20 nm. Furthermore, one type of filter can be used alone, or multiple filters can be used in combination. The filtration method can involve passing the liquid only once, but more preferably, multiple filtrations involving liquid circulation. The filtration steps can be performed in any order and number of times during the polymer manufacturing process, preferably filtering the reaction solution, polymer solution, or both after the polymerization reaction.

[0822] (B) The base polymer may be used alone or in combination with two or more polymers having different composition ratios, Mw and / or Mw / Mn. In addition, (B) the base polymer may contain hydrides of ring-opening shift polymers in addition to the polymers mentioned above. In this regard, the substances described in Japanese Patent Application Publication No. 2003-66612 may be used.

[0823] [(C) Organic solvent]

[0824] The chemically amplified resist composition of the present invention may include an organic solvent as component (C). There are no particular limitations on the organic solvent (C), as long as it can dissolve the aforementioned components and the components described later. 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; ketols 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, EL, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as GBL; and mixtures thereof.

[0825] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, EL, DAA and mixtures thereof are preferred as having particularly excellent solubility in the base polymer of component (B).

[0826] In the chemically amplified resist composition of the present invention, the content of (C) organic solvent is preferably 200 to 8000 parts by mass relative to 80 parts by mass of (B) base polymer, more preferably 400 to 6000 parts by mass. (C) organic solvent may be used alone or in combination of two or more.

[0827] [(D) Quenching agent]

[0828] The chemically amplified resist composition of the present invention may include a quencher as a component (D). Furthermore, in the present invention, a quencher refers to a material used to prevent the diffusion of acid generated by the photoacid generator in the chemically amplified resist composition into the unexposed area, thereby forming a desired pattern.

[0829] As a (D) quencher, examples include onium salts represented by the following formulas (2) or (3).

[0830] [Chemistry 278]

[0831]

[0832] In equation (2), R q1 It is a hydrocarbon group with 1 to 40 carbon atoms, which may contain hydrogen atoms or heteroatoms, except where the hydrogen atom at the α-position of the sulfonic acid group is substituted with a fluorine atom or a fluoroalkyl group. In formula (3), R q2 Hydrocarbon groups consisting of 1 to 40 carbon atoms, which may also contain heteroatoms.

[0833] R q1The hydrocarbon groups representing 1 to 40 carbon atoms include, specifically: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, and other alkyl groups with 1 to 40 carbon atoms; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norcamphenyl, tricyclic [5.2.1.0] 2,6 Cyclic saturated hydrocarbon groups with 3 to 40 carbon atoms, such as decyl and adamantyl; aryl groups with 6 to 40 carbon atoms, such as phenyl, naphthyl, and anthracene. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. A portion of the -CH2- group in the aforementioned hydrocarbon groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, groups that can include hydroxyl, fluorine, chlorine, bromine, iodine, cyano, carbonyl, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentalide rings, carboxylic anhydrides (-C(=O)-OC(=O)-), and haloalkyl groups, etc.

[0834] R q2 The hydrocarbon group represented, specifically, includes those that can be listed as R q1 In addition to the substituents exemplified in the specific examples, other examples include fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl.

[0835] Specific examples of onium salt anions represented by formula (2) can be listed below, but are not limited to these.

[0836] [Chemistry 279]

[0837]

[0838] [Chemistry 280]

[0839]

[0840] [Chemistry 281]

[0841]

[0842] [Chemistry 282]

[0843]

[0844] [Chemistry 283]

[0845]

[0846] Specific examples of onium salt anions represented by formula (3) can be listed below, but are not limited to these.

[0847] [Chemistry 284]

[0848]

[0849] [Chemistry 285]

[0850]

[0851] [Chemistry 286]

[0852]

[0853] [Chemistry 287]

[0854]

[0855] [Chemistry 288]

[0856]

[0857] In equations (2) and (3), Mq + The cation is an onium cation. Examples of onium cations include sulfonium cations, ferrophosphate cations, and ammonium cations. Specific examples of the aforementioned sulfonium cations and ferrophosphate cations can be listed and described in the explanations of formulas (c2) to (c5). + The examples of sulfonium cations and monium cations are similar to those shown, but are not limited to these. As specific examples of the aforementioned ammonium cations, those represented by the following formula (am-1) can be cited.

[0858] [Chemistry 289]

[0859]

[0860] In equation (am-1), R q11 ~R q14 Each can be an independent hydrocarbon group with 1 to 40 carbon atoms, and may also contain heteroatoms. Additionally, R... q11 and R q12 They can bond to each other and form rings together with the nitrogen atoms to which they are bonded. Specific examples of the aforementioned hydrocarbon groups can be listed and described in the explanation of formula (1A) regarding R. 1 The hydrocarbon group is the same group as the exemplified group.

[0861] Specific examples of ammonium cations represented by formula (am-1) can be given as shown below, but are not limited to these.

[0862] [Chemistry 290]

[0863]

[0864] As specific examples of onium salts represented by formula (2) or formula (3), any combination of the aforementioned anions and cations can be listed. Furthermore, these onium salts can be easily prepared by ion exchange reactions using known organic chemical methods. For example, Japanese Patent Application Publication No. 2007-145797 can be consulted regarding ion exchange reactions.

[0865] The onium salts represented by formula (2) or (3) function as quenchers in the chemically amplified resist composition of the present invention. This is because the relative anions of the aforementioned onium salts are conjugate bases of weak acids. The weak acid referred to here is a substance that exhibits an acidity that cannot deprotect the acid-instable groups of units containing acid-instable groups used in the base polymer. The onium salts represented by formula (2) or (3) function as quenchers when used in combination with the conjugate base of a strong acid such as sulfonic acid with fluorinated α-position as an onium salt-type photoacid generator with a relative anion. That is, when an onium salt that generates a strong acid such as sulfonic acid with fluorinated α-position is used in combination with an onium salt that generates a weak acid such as unfluorinated sulfonic acid or carboxylic acid, if the strong acid generated by the photoacid generator by high-energy ray irradiation collides with the unreacted onium salt with a weak acid anion, the weak acid is released through salt exchange, and an onium salt with a strong acid anion is generated. In this process, the strong acid is exchanged for a weaker acid with lower catalytic activity. Therefore, the acid appears to be deactivated, and acid diffusion can be controlled.

[0866] Alternatively, as a (D) quencher, onium salts having sulfonium cations and phenolic anions within the same molecule as described in Japanese Patent No. 6848776, onium salts having sulfonium cations and carboxylate anions within the same molecule as described in Japanese Patent No. 6583136 and Japanese Patent Application Publication No. 2020-200311, and onium salts having uranium cations and carboxylate anions within the same molecule as described in Japanese Patent No. 6274755 may also be used.

[0867] Here, it is argued that when the photoacid generator producing a strong acid is an onium salt, as mentioned above, the strong acid generated by high-energy ray irradiation can be exchanged for a weak acid. However, on the other hand, the weak acid generated by high-energy ray irradiation is difficult to exchange with the unreacted onium salt that generates the strong acid. This is because onium cations more readily form ion pairs with the anions of strong acids.

[0868] When the chemically amplified resist composition of the present invention includes an onium salt represented by formula (2) or (3) as the (D) quencher, its content is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, relative to 80 parts by mass of the (B) base polymer. If the onium salt type quencher of component (D) is within the above range, the resolution is good and the sensitivity is not significantly reduced, which is therefore ideal. The onium salt represented by formula (2) or (3) can be used alone or in combination of two or more.

[0869] The chemically amplified resist composition of the present invention may contain a nitrogen-containing compound as a (D) quencher. Examples of nitrogen-containing compounds as the (D) component include primary, secondary, or tertiary amine compounds described in Japanese Patent Application Publication No. 2008-111103

[0146] to

[0164] , particularly amine compounds having hydroxyl, ether, ester, lactone ring, cyano, or sulfonate groups. Furthermore, compounds that protect primary or secondary amines with urethane groups, such as those described in Japanese Patent No. 3790649, can also be cited.

[0870] Alternatively, sulfonate sulfonates with nitrogen-containing substituents can be used as nitrogen-containing compounds. Such compounds function as quenchers in the unexposed areas, while the exposed areas lose their quenching ability through neutralization with the acid they generate, functioning as so-called photodegradable bases. By using photodegradable bases, the contrast between the exposed and unexposed areas can be further enhanced. Examples of photodegradable bases can be found in, for example, Japanese Patent Application Laid-Open Nos. 2009-109595 and 2012-46501.

[0871] When the chemically amplified resist composition of the present invention includes a nitrogen-containing compound as a quencher (D), its content relative to 80 parts by mass of the base polymer (B) is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass. The aforementioned nitrogen-containing compound may be used alone or in combination of two or more.

[0872] [(E) Other photoacid generating agents]

[0873] The chemically amplified resist composition of the present invention may include a photoacid generator (hereinafter also referred to as other photoacid generators) other than component (A) as component (E). As other photoacid generators, there are no particular limitations as long as they are photoacid generators that generate acid by irradiation with high-energy rays. As preferred other photoacid generators, photoacid generators shown in formula (4) or (5) below can be cited.

[0874] [Chemistry 291]

[0875]

[0876] In equation (4), R 101 ~R 105 Each can be an independent hydrocarbon group with 1 to 20 carbon atoms, and may also contain heteroatoms. Additionally, R... 101 R 102 and R 103 Any two of them can bond together and form a ring with the sulfur atoms they are bonded to.

[0877] Specific examples of the cations of the sulfonium salt shown in formula (4) and the cations of the sulfonium salt shown in formula (5) include, for example, those mentioned in the descriptions of formulas (c2) to (c5). + The examples of sulfonium cations and monazine cations are the same as those shown, but are not limited to these.

[0878] In equations (4) and (5), Xa - It is the anion of a strong acid. The anions of the aforementioned strong acids can be listed as any of the anions represented by formulas (c1-1) to (c1-5).

[0879] In addition, other photoacid generating agents as component (E) are preferably substances shown in the following formula (6).

[0880] [Chemistry 292]

[0881]

[0882] In equation (6), R 201 and R 202 Each can be an independent hydrocarbon group with 1 to 30 carbon atoms, and may also contain heteroatoms. R 203 It can also contain a hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. Additionally, R... 201 R 202 and R 203 Any two of them can bond together and form a ring with the sulfur atoms they are bonded to.

[0883] R 201 and R 202 The hydrocarbon group representing 1 to 30 carbon atoms can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples include alkyl groups with 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, norbornel, oxanorbornel, and tricyclic [5.2.1.0]. 2,6] Decyl, adamantyl, and other cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms; 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, anthracene, and other aryl groups with 6 to 30 carbon atoms; groups obtained by combining them, etc. In addition, some or all of the hydrogen atoms in the above-mentioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. A portion of the -CH2- in the above-mentioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it can contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0884] R 203 The alkylene groups representing carbon atoms from 1 to 30 can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples 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, and hexadecane-1,16-diyl. Dialkyl groups with 1 to 30 carbon atoms, such as heptadecanyl-1,17-dialkyl; cyclopentanediyl, cyclohexanediyl, norcamphenediyl, adamantanediyl, etc., with 3 to 30 carbon atoms; and aryl 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, tert-butylnaphthylene, etc. Furthermore, some or all of the hydrogen atoms in the aforementioned alkylene group can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and a portion of the -CH2- group in the aforementioned alkylene group can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the group may contain hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulopentalide ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc. Oxygen atoms are preferred as the aforementioned heteroatoms.

[0885] In equation (6), L21 It is a single bond, an ether bond, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples include R... 203 The group represented by the alkylene group is the same group as the one exemplified by the alkylene group.

[0886] In equation (6), X a X b X c and X d Each can be independently a hydrogen atom, a fluorine atom, or a trifluoromethyl atom. However, X a X b X c and X d At least one of them is a fluorine atom or a trifluoromethyl atom.

[0887] As the photoacid generator shown in formula (6), it is preferred to be the photoacid generator shown in formula (6') below.

[0888] [Chemistry 293]

[0889]

[0890] In equation (6'), L 21 Same as above. X e It can be a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 301 R 302 and R 303 Each hydrocarbon group consists independently of a hydrogen atom or may contain heteroatoms and has 1 to 20 carbon atoms. These hydrocarbon groups can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples include R in formula (c1-1-1). fa1 The alkyl group is the same group as the exemplified group. p and q are each independently 0, 1, 2, 3, 4 or 5, and r is 0, 1, 2, 3 or 4.

[0891] As the photoacid generator shown in formula (6), the same photoacid generator as the photoacid generator shown in formula (2) of Japanese Patent Application Publication No. 2017-26980 can be cited.

[0892] Among the other photoacid generators mentioned above, those containing anions represented by formula (c1-1-1) or (c1-4) exhibit low acid diffusivity and excellent solubility in solvents, making them particularly desirable. Furthermore, the photoacid generator represented by formula (6') exhibits extremely low acid diffusivity, making it particularly desirable.

[0893] When the chemically amplified resist composition of the present invention includes (E) other photoacid generating agents, the content of these agents is preferably 0.1 to 40 parts by weight, and more preferably 0.5 to 20 parts by weight, relative to 80 parts by weight of the (B) base polymer. If the amount of (E) photoacid generating agent added is within the above range, the resolution is good, and there is no risk of foreign matter generation after development or during stripping of the resist film, which is therefore ideal. (E) Other photoacid generating agents can be used alone or in combination of two or more.

[0894] [(F) Surfactant]

[0895] The chemically amplified resist composition of the present invention may further include a surfactant as component (F). Preferably, the surfactant (F) is a surfactant that is insoluble or poorly soluble in water but soluble in alkaline developing solution, or a surfactant that is insoluble or poorly soluble in both water and alkaline developing solution. Such surfactants can be referred to in Japanese Patent Application Publication Nos. 2010-215608 and 2011-16746.

[0896] As surfactants that are insoluble or poorly soluble in water and alkaline developing solutions, the surfactants described in the above-mentioned announcement are preferably FC-4430 (manufactured by 3M Corporation), SURFLON (registered trademark) S-381 (manufactured by AGC SEIMI CHEMICAL CO., LTD.), OLFINE (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC SEIMI CHEMICAL Co., Ltd.), and the oxetane ring-opening polymer shown in the following formula (surf-1).

[0897] [Chemistry 294]

[0898]

[0899] Here, R, Rf, A, B, C, m, and n are irrelevant to the aforementioned descriptions and apply only to formula (surf-1). R is an aliphatic group with 2 to 5 carbon atoms in a 2 to 4-valent configuration. Examples of the aforementioned aliphatic groups that are divalent include ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, and 1,5-pentylene; examples of groups that are trivalent or tetravalent include the following.

[0900] [Chemistry 295]

[0901]

[0902] In the formula, the dashed lines represent atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and neopentyl tertrol, respectively.

[0903] However, 1,4-butylene, 2,2-dimethyl-1,3-propylene, etc. are preferred.

[0904] Rf is trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. 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, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. Furthermore, the arrangement of the structural units in formula (surf-1) is not predetermined; they can be block-bonded or randomly bonded. The manufacture of surfactants based on partially fluorinated oxyheterocyclic butane ring-opening polymer systems is described in detail in U.S. Patent No. 5,650,483, etc.

[0905] In ArF immersion lithography, where no resist protective film is used, surfactants that are insoluble or sparingly soluble in water but soluble in alkaline developer can reduce water penetration and leaching by aligning with the surface of the resist film. Therefore, they can be used to reduce damage to the exposure apparatus by inhibiting the dissolution of water-soluble components from the resist film, and are useful because they dissolve in alkaline aqueous solutions after exposure or post-exposure baking (PEB) and are unlikely to become foreign matter causing defects. Such surfactants, which are insoluble or sparingly soluble in water but soluble in alkaline developer, are polymeric surfactants, also known as hydrophobic resins, and are particularly preferred as surfactants with high water repellency and improved hydrophobicity.

[0906] As a specific example of such polymeric surfactants, those comprising at least one repeating unit selected from any of the following formulas (7A) to (7E) can be cited.

[0907] [Chemistry 296]

[0908]

[0909] In equations (7A) to (7E), R B It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. W 1 It can be -CH2-, -CH2CH2-, -O-, or two separate -H. R s1 Each is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R s2 It is a single bond or a straight-chain or branched alkylene group with 1 to 5 carbon atoms. R s3 Each is independently a hydrogen atom, a hydrocarbon group with 1 to 15 carbon atoms, a fluorinated hydrocarbon group, or an acid-labile group. R s3 In the case of a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group can be inserted between the carbon-carbon bonds. R s4 It is a (u+1) valence hydrocarbon group or a fluorinated hydrocarbon group with 1 to 20 carbon atoms. u can be 1, 2, or 3. Rs5 Each is independently a hydrogen atom, or -C(=O)-OR sa The group indicated by R. sa It is a fluorinated hydrocarbon group with 1 to 20 carbon atoms. R s6 It is a hydrocarbon group or fluorinated hydrocarbon group with 1 to 15 carbon atoms, and an ether bond or carbonyl group may be inserted between its carbon-carbon bonds.

[0910] R s1 The hydrocarbon group representing 1 to 10 carbon atoms is preferably a saturated hydrocarbon group, and can be straight-chain, branched, or cyclic. Specific examples include alkyl groups with 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 with 3 to 10 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornel. Among these, those with 1 to 6 carbon atoms are preferred.

[0911] R s2 The represented hydrocarbon group is preferably a saturated hydrocarbon group, and can be straight-chain, branched, or cyclic. Specific examples include methylene, ethylene, propylene, butylene, and pentylene.

[0912] R s3 or R s6 The hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples include aliphatic unsaturated hydrocarbon groups such as saturated hydrocarbon groups, alkenyl groups, and alkynyl groups, with saturated hydrocarbon groups being preferred. As an example of the aforementioned saturated hydrocarbon group, R... s1 Examples of hydrocarbon groups to be represented include undecyl, dodecyl, tridecyl, tetradecyl, and pentadecyl. As R s3 or R s6 The term "fluorinated hydrocarbon group" refers to a group in which some or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon group are replaced by fluorine atoms. As mentioned above, ether bonds or carbonyl groups may be inserted between these carbon-carbon bonds.

[0913] R s3 Specific examples of acid-instable groups include groups represented by formulas (AL-3) to (AL-5), trialkylsilyl groups where each alkyl group has 1 to 6 carbon atoms, and alkyl groups containing oxy groups with 4 to 20 carbon atoms.

[0914] R s4 The (u+1) valence hydrocarbon group or fluorinated hydrocarbon group can be any of the straight-chain, branched, or cyclic forms. As a specific example, groups obtained by further removing u hydrogen atoms from the above-mentioned hydrocarbon group or fluorinated hydrocarbon group can be given.

[0915] R saThe fluorinated hydrocarbon group is preferably saturated and can be straight-chain, branched, or cyclic. Specific examples include groups in which some or all of the hydrogen atoms of the aforementioned hydrocarbon group are replaced by fluorine atoms. Examples include trifluoromethyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoro-1-propyl, 3,3,3-trifluoro-2-propyl, 2,2,3,3-tetrafluoropropyl, 1,1,1,3,3,3-hexafluoroisopropyl, 2,2,3,3,4,4,4-heptafluorobutyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 2,2,3,3,4,4,5,5,6,6,7,7-dodecylfluoroheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, 2-(perfluorodecyl)ethyl, etc.

[0916] Specific examples of repeating units represented by any of equations (7A) to (7E) can be listed below, but are not limited to these. Furthermore, in the following equations, R... B Same as above.

[0917] [Chemistry 297]

[0918]

[0919] [Chemistry 298]

[0920]

[0921] [Chemistry 299]

[0922]

[0923] [Chemical 300]

[0924]

[0925] [Chemical Engineering 301]

[0926]

[0927] [Chemical 302]

[0928]

[0929] The aforementioned polymeric surfactant may also contain repeating units other than those represented by formulas (7A) to (7E). Examples of other repeating units include repeating units obtained from methacrylic acid, α-trifluoromethacrylic acid derivatives, etc. In the polymeric surfactant, the content of the repeating units represented by formulas (7A) to (7E) is preferably 20 mol% or more, more preferably 60 mol% or more, and even more preferably 100 mol% of all repeating units.

[0930] The Mw of the aforementioned polymeric surfactant is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. The Mw / Mn ratio is preferably 1.0 to 2.0, more preferably 1.0 to 1.6.

[0931] One method for synthesizing the aforementioned polymeric surfactants is as follows: A monomer containing unsaturated bonds, providing repeating units represented by formulas (7A) to (7E) and other repeating units as needed, is polymerized in an organic solvent by adding a free radical initiator and heating. Examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, and dioxane. Examples of polymerization initiators include AIBN, 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl 2,2-azobis(2-methylpropionic acid), benzoyl peroxide, and lauroyl peroxide. The preferred reaction temperature is 50–100°C. The preferred reaction time is 4–24 hours. Acid-insecure groups can be directly introduced into the monomer, or they can be protected or partially protected after polymerization.

[0932] In synthesizing the aforementioned polymeric surfactants, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can be used to adjust the molecular weight. In this case, the amount of these chain transfer agents added is preferably 0.01 to 10 mol% relative to the total molar number of the monomers being polymerized.

[0933] When the chemically amplified resist composition of the present invention includes surfactant (F), its content is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the base polymer (B). If the content of surfactant (F) is 0.1 parts by mass or more, the receding contact angle between the resist film surface and water is sufficiently increased; if it is 50 parts by mass or less, the dissolution rate of the resist film surface relative to the developer is low, thus sufficiently maintaining the height of the formed fine pattern. Surfactant (F) can be used alone or in combination of two or more.

[0934] [(G) Other ingredients]

[0935] The chemically amplified resist composition of the present invention may contain (G) other components, such as: compounds that decompose to produce acid under the action of acid (acid-increasing compounds), organic acid derivatives, fluorinated alcohols, and compounds with a solubility of Mw3000 or less in the developer that changes due to the action of acid (dissolution inhibitors). As the aforementioned acid-increasing compounds, the compounds described in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608 can be referred to. When containing the aforementioned acid-increasing compounds, their content is preferably 0 to 5 parts by mass relative to 80 parts by mass of the (B) base polymer, more preferably 0 to 3 parts by mass. If the content is too high, it is difficult to control acid diffusion, and sometimes it may cause degradation of resolution and pattern shape. As the aforementioned organic acid derivatives, fluorinated alcohols, and dissolution inhibitors, the compounds described in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608 can be referred to.

[0936] [Pattern Formation Method]

[0937] The pattern forming method of the present invention includes the steps of forming a resist film on a substrate using the aforementioned chemically amplified resist composition; exposing the aforementioned resist film to high-energy rays; and developing the aforementioned exposed resist film using a developer.

[0938] Examples of substrates used in the aforementioned manufacturing process include substrates for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective film, etc.) or substrates for shielding circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.).

[0939] The resist film can be formed, for example, by applying the aforementioned chemically amplified resist composition onto a substrate using a spin coating method with a film thickness preferably of 0.05 to 2 μm, and pre-baking it on a hot plate at a temperature preferably of 60°C to 150°C for 1 to 10 minutes, more preferably of 80°C to 140°C for 1 to 5 minutes.

[0940] Examples of high-energy rays used for exposure of resist films include KrF excimer lasers, ArF excimer lasers, EB, and EUV at 3–15 nm. Regarding exposure, when using KrF excimer lasers, ArF excimer lasers, or EUV, a shielding method for forming the target pattern should be used, with an exposure dose preferably between 1 and 200 mJ / cm². 2 The optimal value is 10–100 mJ / cm³. 2 Irradiation is performed in the following manner. When using EB, exposure is performed using a shield to form the target pattern or directly, with an exposure dose preferably of 1–300 μC / cm. 2The optimal value is 10–200 μC / cm. 2 Irradiation is performed in this manner.

[0941] In addition to the usual exposure method, an immersion method can also be used, in which a liquid with a refractive index of 1.0 or higher is placed between the resist film and the projection lens. In this case, a water-insoluble protective film can also be used.

[0942] The aforementioned water-insoluble protective film is used to prevent leaching from the resist film and improve the hydrophobicity of the film surface. It is broadly classified into two types. One type is an organic solvent-stripping type, which requires stripping with an organic solvent that does not dissolve the resist film before alkaline aqueous solution development. The other type is an alkaline aqueous solution-soluble type, which is soluble in alkaline developing solution and removes the protective film while removing the soluble portion of the resist film. The latter is particularly preferably a material based on a polymer containing 1,1,1,3,3,3-hexafluoro-2-propanol residues that is insoluble in water but soluble in alkaline developing solution, dissolved in an alcohol solvent with 4 or more carbon atoms, an ether solvent with 8 to 12 carbon atoms, or a mixture thereof. Alternatively, a material can be prepared by dissolving the aforementioned water-insoluble surfactant that is soluble in alkaline developing solution in an alcohol solvent with 4 or more carbon atoms, an ether solvent with 8 to 12 carbon atoms, or a mixture thereof.

[0943] After exposure, PEB can be performed. PEB can be performed, for example, by heating on a hot plate at a temperature of 60–150°C for 1–5 minutes, more preferably at a temperature of 80–140°C for 1–3 minutes.

[0944] Developing is performed, for example, using an alkaline aqueous solution of tetramethylammonium hydroxide (TMAH) at a concentration of 0.1-5% by mass, more preferably 2-3% by mass, for a duration of 0.1-3 minutes, more preferably 0.5-2 minutes, by conventional methods such as dip, immersion, or spraying, thereby dissolving the exposed portion and forming the target pattern on the substrate.

[0945] In addition, after the resist film is formed, it can be rinsed with pure water to extract acid-generating agents or particles from the film surface, or it can be rinsed after exposure to remove water remaining on the film.

[0946] Furthermore, patterns can also be formed using a double patterning method. Examples of double patterning methods include: the trench method, which processes a substrate with a 1:3 trench pattern by first exposure and etching, and then forms a 1:3 trench pattern by a second exposure at a staggered position, thereby forming a 1:1 pattern; and the line method, which processes a first substrate with a 1:3 isolated residual pattern by first exposure and etching, and then processes a second substrate with a 1:3 isolated residual pattern formed under the first substrate by a second exposure at a staggered position, thereby forming a 1:1 pattern with a pitch of half.

[0947] In the pattern forming method of the present invention, a negative tone development method can also be used, that is, an organic solvent is used instead of the aforementioned alkaline aqueous solution as the developer to dissolve the unexposed area.

[0948] In the above-mentioned organic solvent development, the developing solution may include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl valerate, and methyl butenoate. These organic solvents include ethyl butenoate, 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 phenyl acetate, ethyl formate, phenyl ethyl formate, methyl 3-phenylpropionate, benzyl propionate, and 2-phenylethyl acetate. These organic solvents can be used alone or in mixtures of two or more.

[0949] Example

[0950] The present invention will now be specifically described with reference to synthetic examples, embodiments, and comparative examples, but the present invention is not limited to the embodiments described below. Furthermore, the apparatus used is as follows.

[0951] • MALDITOF-MS: S3000 manufactured by Nippon Electronics Co., Ltd.

[0952] [1] Synthesis of onium salts

[0953] [Example 1-1] Synthesis of PAG-1

[0954] [Chemical 303]

[0955]

[0956] (1) Synthesis of PAG-1

[0957] Under nitrogen atmosphere, 15.6 g of starting material SM-1, 3.0 g of potassium carbonate, and 30 g of DMF were added to a reaction vessel, and the mixture was stirred at an internal temperature of 60 °C for 6 hours. After stirring, the reaction solution was cooled in an ice bath, and water (30 g) was added to stop the reaction. After extraction with dichloromethane (100 g), the mixture was washed with water and concentrated under reduced pressure. Diisopropyl ether was added to the concentrate for recrystallization, thereby yielding 13.0 g of PAG-1 (86% yield) as the target compound in the form of white crystals.

[0958] The following shows the TOF-MS results for PAG-1.

[0959] MALDI TOF-MS: POSITIVE M + 759 (equivalent to C) 24 H 13 F4I2O4S2 + )

[0960] [Examples 1-2 to 1-10] Synthesis of PAG-2 to PAG-10

[0961] Various onium salts are synthesized using appropriate raw materials and various organic synthesis reactions. The structures of onium salts used in chemically amplified resist compositions are shown below.

[0962] [Chemical 304]

[0963]

[0964] [2] Synthesis of basic polymers

[0965] [Synthetic Example] Synthesis of basic polymers (P-1 to P-5)

[0966] The monomers were combined and copolymerized in MEK as a solvent. The reaction solution was then added to hexane, and the precipitated solid was washed with hexane, isolated, and dried to obtain the base polymers (P-1 to P-5) with the compositions shown below. The composition of the obtained base polymers was determined by... 1 The results were confirmed by H-NMR, and Mw and Mw / Mn were confirmed by GPC (solvent: THF, standard: polystyrene).

[0967] [Chemical 305]

[0968]

[0969] [Chemical 306]

[0970]

[0971] [3] Preparation of chemically amplified resist composition

[0972] [Examples 2-1 to 2-32, Comparative Examples 1-1 to 1-21]

[0973] The sulfonium salts (PAG-1 to PAG-10), comparative photoacid generators (PAG-A to PAG-D), other photoacid generators (PAG-X, PAG-Y), base polymers (P-1 to P-5), and quenchers (Q-1 to Q-4) of the present invention were dissolved in a solvent containing 0.01% by mass of surfactant A (Omnova) to prepare a solution. The solution was then filtered using a 0.2 μm Teflon (registered trademark) type filter to prepare chemically amplified resist compositions (R-1 to R-32, CR-1 to CR-21).

[0974] [Table 1]

[0975]

[0976]

[0977] [Table 2]

[0978]

[0979] In Tables 1 and 2, the solvents, other photoacid generators PAG-X and PAG-Y, comparative photoacid generators PAG-A to PAG-D, and quenchers Q-1 to Q-4 are as follows.

[0980] Solvent: PGMEA (Propylene Glycol Monomethyl Ether Acetate)

[0981] EL (ethyl lactate)

[0982] DAA (diacetone alcohol)

[0983] Other photoacid generators: PAG-X, PAG-Y

[0984] [Chemical 307]

[0985]

[0986] • Comparison of photoacid generating agents: PAG-A to PAG-D

[0987] [Chemical 308]

[0988]

[0989] Quenching agents: Q-1 to Q-4

[0990] [Chemical 309]

[0991]

[0992] [4] Evaluation of EUV lithography (1)

[0993] [Examples 3-1 to 3-35, Comparative Examples 2-1 to 2-21]

[0994] The chemically amplified resist compositions (R-1 to R-32, CR-1 to CR-21) shown in Tables 1 and 2 were spin-coated onto a Si substrate with a 20 nm thick silicon spin-coated hard shielding material (SHB-A940, 43% by mass, manufactured by Shin-Etsu Chemical Industries, Ltd.). The substrate was pre-baked at 100°C for 60 seconds using a hot plate to create a 50 nm thick resist film. For the aforementioned resist film, an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, dipole illumination) was used, with varying exposure and focal length (exposure pitch: 1 mJ / cm). 2 Simultaneously, an LS pattern with a size of 18 nm and a pitch of 36 nm was exposed on the chip (focusing pitch: 0.020 μm). After exposure, PEB was performed for 60 seconds at the temperatures shown in Tables 3 and 4. Then, immersion development was performed for 30 seconds with a 2.38% by mass TMAH aqueous solution, followed by rinsing with a rinsing material containing surfactant and spin drying to obtain a positive pattern.

[0995] The LS pattern obtained by observation using a Hitachi Advanced Technology Co., Ltd. measuring SEM (CG6300) was evaluated for sensitivity, EL, LWR, depth of focus (DOF), and collapse limit according to the following methods. The results are shown in Tables 3 and 4.

[0996] [Sensitivity Evaluation]

[0997] Find the optimal exposure Eop (mJ / cm) for obtaining an LS pattern with a linewidth of 18nm and a pitch of 36nm. 2 This value is used as the sensitivity. The smaller the value, the higher the sensitivity.

[0998] [EL Review]

[0999] The EL (in %) is calculated using the following formula, based on the exposure within ±10% (16.2–19.8 nm) of the 18 nm pitch width in the aforementioned LS pattern. The larger this value, the better the performance.

[1000] EL(%)=(|E1-E2| / Eop)×100

[1001] E1: Provides optimal exposure for LS patterns with a linewidth of 16.2nm and a pitch of 36nm.

[1002] E2: Provides optimal exposure for LS patterns with a linewidth of 19.8nm and a pitch of 36nm.

[1003] Eop: Provides optimal exposure for LS patterns with a linewidth of 18nm and a pitch of 36nm.

[1004] [LWR Evaluation]

[1005] For an LS pattern obtained by Eop irradiation, the dimensions of 10 locations along the length of the line are measured, and the standard deviation (σ) is calculated as three times the value of the result (3σ) as the LWR. The smaller this value, the smaller the roughness and the more uniform the line width of the pattern.

[1006] [DOF Rating]

[1007] As an evaluation of depth of focus, the focal range formed within ±10% (16.2–19.8 nm) of the 18 nm size in the aforementioned LS pattern is determined. The larger this value, the wider the depth of focus.

[1008] [Collapse Limit Assessment of Line Patterns]

[1009] The line dimensions of the optimal focal point for each exposure of the above-mentioned LS pattern were measured at 10 locations along the length direction. The finest line dimension obtained without collapse was taken as the collapse limit dimension. The smaller this value, the better the collapse limit.

[1010] [Table 3]

[1011]

[1012] [Table 4]

[1013]

[1014] As shown in Tables 3 and 4, the chemically amplified resist composition containing the onium salt of the present invention exhibits good sensitivity, and excellent EL, LWR, and DOF. Furthermore, it was confirmed that the collapse limit value is small, indicating resistance to pattern collapse during fine pattern formation. Therefore, the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[1015] [5] Evaluation of EUV lithography (2)

[1016] [Examples 4-1 to 4-35, Comparative Examples 3-1 to 3-21]

[1017] The chemically amplified resist compositions (R-1 to R-32, CR-1 to CR-21) shown in Tables 1 and 2 were spin-coated onto a Si substrate with a 20 nm thick silicon-containing spin-coated hard shielding material (SHB-A940, 43% by mass) manufactured by Shin-Etsu Chemical Industry Co., Ltd. The substrate was pre-baked at 105°C for 60 seconds using a hot plate to create a 50 nm thick resist film. The resist film was then exposed using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, shielding of a 46 nm pitch hole pattern with +20% tolerance on the wafer). PEB was performed for 60 seconds at the temperatures described in Tables 5 and 6 using a hot plate, followed by 30 seconds of development with a 2.38% by mass TMAH aqueous solution to form a 23 nm hole pattern.

[1018] Using a Hitachi Advanced Technologies (AG) CG6300 length-measuring SEM, the exposure was measured at a hole size of 23 nm, and this was used as the sensitivity. In addition, the size of 50 holes at this time was measured, and three times the standard deviation (σ) calculated from the results (3σ) was used as the CDU. The results are shown in Tables 5 and 6.

[1019] [Table 5]

[1020]

[1021] [Table 6]

[1022]

[1023] The results shown in Tables 5 and 6 confirm that the chemically amplified resist composition containing the onium salt of the present invention exhibits good sensitivity and excellent CDU.

Claims

1. An onium salt, represented by the following formula (1), In the formula, n1 is 0 or 1, n2 is 1, 2, 3 or 4, n3 is 0, 1 or 2, but when n1 is 0, 1≤n2+n3≤4, when n1 is 1, 1≤n2+n3≤6, n4 is 0 or 1, and n5 is 0, 1, 2, 3 or 4. R a The radical can be a halogen atom other than an iodine atom, a nitro group, a cyano group, a hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. When n3 is 2, there are 2 R radicals. a They can be the same or different, 2 Rs a They can bond to each other and form rings together with the carbon atoms they are bonded to. R b The R group can be a halogen atom, nitro group, cyano group, hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms containing heteroatoms. When n5 is 2, 3, or 4, each R group... b They can be the same or different, multiple Rs b They can bond to each other and form rings together with the carbon atoms they are bonded to. R 1 and R 2 Each is an independent hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. Additionally, R... 1 R 2 and the S bonded in the formula + Any two atoms in an aromatic ring can bond to each other and form a ring together with the sulfur atoms they are bonded to. L A and L B Each bond can be independently a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond. X L1 It is a single bond, or may contain heteroatoms and a hydrocarbon group with 1 to 40 carbon atoms.

2. The onium salt according to claim 1, represented by the following formula (1A), In the formula, n1~n5, R a R b L A L B X L1 Same as above, n6 can be 0 or 1, n7 can be 0, 1 or 2, n8 can be 0, 1, 2, 3 or 4, n9 can be 0 or 1, n10 can be 0, 1 or 2, and n11 can be 0, 1, 2, 3 or 4. However, when n6 is 0, 0 ≤ n7 + n8 ≤ 5; when n6 is 1, 0 ≤ n7 + n8 ≤ 7. Also, when n9 is 0, 0 ≤ n10 + n11 ≤ 5; when n9 is 1, 0 ≤ n10 + n11 ≤ 7. R c The radical can be a halogen atom other than fluorine, a nitro group, a cyano group, a hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. When n7 is 2, there are 2 R radicals. c They can be the same or different, 2 Rs c They can bond to each other and form rings together with the carbon atoms they are bonded to. R d The radical can be a halogen atom other than fluorine, a nitro group, a cyano group, a hydroxyl group, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. When n10 is 2, there are 2 R radicals. d They can be the same or different, 2 Rs d They can bond to each other and form rings together with the carbon atoms they are bonded to. R F1 and R F2 Each of the following is independently a fluorine atom, a pentafluorosulfur group, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon sulfur group having 1 to 6 carbon atoms. When n8 is 2 or more, each R F1 They can be the same or different. When n11 is 2 or more, each R F2 They can be the same or different.

3. The onium salt according to claim 2, represented by the following formula (1B), In the formula, n1~n11, R a R b R c R d R F1 R F2 and L A Same as above.

4. A photoacid generator comprising an onium salt according to any one of claims 1 to 3.

5. A chemically amplified resist composition comprising the photoacid generator according to claim 4.

6. The chemically amplified resist composition according to claim 5 further comprises a base polymer containing at least one repeating unit selected from the repeating units represented by formula (a1), formula (a2), and formula (a3). In the formula, R A Each is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -or *-C(=O)-NH-X 11 - The phenylene or naphthylene group may also be substituted by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group containing fluorine atoms with 1 to 10 carbon atoms, a saturated hydrocarbon oxygen group containing fluorine atoms with 1 to 10 carbon atoms, or a halogen atom. X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group having 1 to 10 carbon atoms. The saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. X 2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * indicates an atomic bond with a carbon atom in the main chain. R 11 The radical can be a halogen atom, cyano group, hydroxyl group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon oxygen group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms containing heteroatoms. When a1 is 2, 3, or 4, each R... 11 They can be the same or different. AL 1 and AL 2 Each is an independent acid-labile group. a1 is 0, 1, 2, 3, or 4. In the formula, b1 is 0 or 1, and b2 is 0, 1, 2 or 3 when b1 is 0, and 0, 1, 2, 3, 4 or 5 when b1 is 1. R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 3 These are single bonds, *-C(=O)-O-, or *-C(=O)-NH-, where * indicates an atomic bond with a carbon atom in the main chain. X 4 It is a single bond, an aliphatic alkylene group, carbonyl group, sulfonyl group, or a combination thereof, consisting of 1 to 4 carbon atoms. X 5 and X 6 Each can be independently an oxygen atom or a sulfur atom, but X 4 and X 6 Bonded to adjacent carbon atoms of the aromatic ring, R 12 and R 13 Each is an independent hydrocarbon group consisting of 1 to 20 carbon atoms, or may contain heteroatoms. Additionally, R... 12 and R 13 They can also bond to each other and form rings together with the carbon atoms they are bonded to. R 14 It may contain halogen atoms, hydroxyl groups, cyano groups, nitro groups, or hydrocarbon groups with 1 to 20 carbon atoms containing heteroatoms; hydrocarbon oxy groups with 1 to 20 carbon atoms containing heteroatoms; hydrocarbon oxycarbonyl groups with 2 to 20 carbon atoms containing heteroatoms; or hydrocarbon thio groups with 1 to 20 carbon atoms containing heteroatoms, or -N(R) groups. 14A (R) 14B ), R 14A and R 14B Each is independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms; when b2 is 2 or more, each R 14 They can be the same or different, multiple Rs 14 They can bond to each other and form rings together with the carbon atoms of the aromatic rings they are bonded to.

7. The chemically amplified resist composition according to claim 6, wherein, The base polymer comprises at least one repeating unit selected from the repeating units represented by formula (b1) and formula (b2) below. In the formula, R A Each is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y 1 It represents a single bond or *-C(=O)-O-, where * indicates an atomic bond with a carbon atom in the main chain. R 21 It is a hydrogen atom, or a group containing at least one of the following structures with 1 to 20 carbon atoms: hydroxyl group (other than phenolic hydroxyl group), cyano group, carbonyl group, carboxyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulcinolone ring, and carboxylic anhydride (-C(=O)-OC(=O)-). R 22 The group can be a halogen atom, hydroxyl group, carboxyl group, nitro group, cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon oxygen group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms containing heteroatoms. When c2 is 2, 3, or 4, each R... 22 They can be the same or different. c1 can be 1, 2, 3 or 4, and c2 can be 0, 1, 2, 3 or 4, but 1≤c1+c2≤5.

8. The chemically amplified resist composition according to claim 6, wherein, The base polymer comprises at least one repeating unit selected from the following formula (c1), repeating unit represented by the following formula (c2), repeating unit represented by the following formula (c3), repeating unit represented by the following formula (c4), and repeating unit represented by the following formula (c5). In the formula, d1 and d2 are each independently 0, 1, 2, or 3; e1 is 0 or 1; e2 is 0, 1, 2, 3, or 4; and e3 is 0, 1, 2, 3, or 4. However, when e1 is 0, 0 ≤ e2 + e3 ≤ 4; and when e1 is 1, 0 ≤ e2 + e3 ≤ 6. R A Each is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z 1 It can be a single bond or may have substituents, phenylene Z 2 Indicates a single bond, **-C(=O)-OZ 21 -、**-C(=O)-NH-Z 21 -or**-OZ 21 -, Z 21 It is a divalent group consisting of an aliphatic hydrocarbon group, a phenylene group, or a combination thereof, having 1 to 6 carbon atoms, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z 3 The bonds can be single bonds, ether bonds, ester bonds, amide bonds, sulfonate bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Z 4 It is a single bond, or 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. Z 5 Each can be a single bond, or may have substituents such as phenylene, naphthylene, or *-C(=O)-OZ. 51 -, Z 51 It is an aliphatic hydrocarbon group, phenylene, or naphthylene group having 1 to 10 carbon atoms. The aliphatic hydrocarbon group may also contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or a lactone ring. Z 6 The bonds can be single bonds, ether bonds, ester bonds, amide bonds, sulfonate bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Z 7 Each is independently a single bond, ***-Z 71 -C(=O)-O-、***-C(=O)-NH-Z 71 -or ***-OZ 71 -, Z 71 It may also contain a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. Z 8 Each is independently a single key, ****-Z 81 -C(=O)-O-、****-C(=O)-NH-Z 81 -or ****-OZ 81 -, Z 81 It may also contain a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. Z 9 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, fluorinated phenylene, or phenylene substituted with trifluoromethyl, having 1 to 6 carbon atoms, and may contain a carbonyl group, ester bond, ether bond, or hydroxyl group. * indicates an atomic bond with a carbon atom in the main chain, ** indicates an atomic bond with a Z atom. 1 atomic bonds, *** indicates the relationship with Z 6 atomic bonds, **** indicates the relationship with Z 7 atomic bonds, L 1 The bonds can be single bonds, ether bonds, ester bonds, carbonyl groups, sulfonate bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Rf 1 and Rf 2 Each is independently 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 is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; however, all Rf 5 and Rf 6 They are not both hydrogen atoms. Rf 7 It is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated alkylthio group having 1 to 6 carbon atoms. R 31 and R 32 Each can be an independent hydrocarbon group with 1 to 20 carbon atoms, and may also contain heteroatoms. Additionally, R... 31 and R 32 They can also bond to each other and form rings together with the sulfur atoms they are bonded to. R 33 When e3 is 2, 3, or 4, each R... 33 They can be the same or different, multiple Rs 33 They can bond to each other and form rings together with the carbon atoms they are bonded to. M - It is a non-nucleophilic relative ion. Z + It is a ium cation.

9. The chemically amplified resist composition according to claim 5 further contains an organic solvent.

10. The chemically amplified resist composition according to claim 5, further comprising a quenching agent.

11. The chemically amplified resist composition according to claim 5, further comprising a photoacid generating agent other than the photoacid generating agent according to claim 4.

12. The chemically amplified resist composition according to claim 5 further comprises a surfactant.

13. A method for forming a pattern, comprising the following steps: A resist film is formed on a substrate using the chemically amplified resist composition according to claim 5; the resist film is exposed to high-energy rays; and the exposed resist film is developed using a developer.

14. The pattern forming method according to claim 13, wherein, The high-energy rays are KrF excimer lasers, ArF excimer lasers, electron beams, or extreme ultraviolet rays with wavelengths of 3–15 nm.

Images