Onium salt, chemically amplified resist composition and pattern forming method

Abstract

The invention relates to an onium salt, a chemically amplified resist composition and a pattern forming method. The present invention addresses the problem of providing: a photolithographic film which has excellent solvent solubility, high sensitivity, and excellent photolithographic properties in optical lithography using high-energy rays; the present invention relates to an onium salt for use in a chemically amplified resist composition having excellent photolithography properties such as exposure latitude (EL) and LWR, having a high contrast, a chemically amplified resist composition containing the onium salt as a photoacid generator, and a method for forming a pattern using the chemically amplified resist composition. The onium salt is represented by the following formula (1).

Description

Technical Field

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

[0002] In recent years, with the increasing integration and speed of LSI and the pursuit of miniaturization of pattern regularity, far-ultraviolet lithography and extreme ultraviolet (EUV) lithography are regarded as the promising next-generation microfabrication technology.

[0003] ArF lithography, using an ArF excimer laser, was partially used starting with the fabrication of devices at the 130nm node and became the primary lithography technology from the 90nm node onwards. Regarding the next 45nm node lithography technology, lithography using the 157nm F2 laser was initially considered promising, but development was delayed due to numerous issues. Therefore, ArF immersion lithography, which allows for a high-resolution projection lens aperture (NA) of 1.0 or higher 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, quickly emerged (Non-Patent Document 1) and entered the practical application stage. This immersion lithography requires a resist composition that is not easily dissolved in water.

[0004] ArF lithography requires highly sensitive resist compositions that achieve sufficient resolution with minimal exposure to prevent degradation of delicate and expensive optical system materials. The most common method for achieving this is to select components with high transparency at a wavelength of 193 nm. For example, for the base polymer, some researchers have proposed polyacrylic acid and its derivatives, nobornene-maleic anhydride alternating polymers, polynobornene, ring-opening metathesis polymers, and ring-opening metathesis polymer hydrides, which have achieved some success in improving the transparency of the resin monomers.

[0005] In recent years, along with positive tone resists developed using alkaline aqueous solutions, negative tone resists developed using organic solvents have also attracted attention. To resolve extremely fine hole patterns that cannot be achieved with positive tone using negative tone exposure, negative patterns are formed by using high-resolution positive resist compositions and developing with organic solvents. Furthermore, research is underway to achieve twice the resolution through a combination of alkaline aqueous solution development and organic solvent development. Regarding ArF resist compositions used for negative tone development with organic solvents, known positive ArF resist compositions and pattern formation methods using them are described in Patent Documents 1-3.

[0006] To adapt to the rapid miniaturization in recent years, the development of process technologies and resist compositions is also progressing rapidly. Various explorations are underway regarding photoacid generators, typically using sulfonium salts composed of triphenylsulfonium cations and perfluoroalkyl sulfonate anions. However, regarding perfluoroalkyl sulfonic acids as the generated acid, perfluorooctane sulfonic acid (PFOS) has concerns about its poor biocompatibility, bioconcentration potential, and toxicity, making its use in resist compositions more stringent. Currently, photoacid generators that produce perfluorobutane sulfonic acid are used. However, when used in resist compositions, the resulting acid diffuses significantly, making it difficult to achieve high resolution. To address this issue, various partially fluorinated alkylsulfonic acids and their salts have been developed. For example, Patent Document 1 describes photoacid generators that produce α,α-difluoroalkylsulfonic acid using exposure as a current technology. Specifically, it describes photoacid generators that produce bis(4-tert-butylphenyl)zimonium 1,1-difluoro-2-(1-naphthyl)ethanesulfonate and α,α,β,β-tetrafluoroalkylsulfonic acid. However, although their fluorine substitution rates are reduced, the lack of decomposable substituents such as ester structures makes consideration of environmental safety due to easy decomposition insufficient. Furthermore, there are limitations in the molecular design for varying the size of alkylsulfonic acids, and the starting materials containing fluorine atoms have high valence.

[0007] Furthermore, with the shrinking of circuit linewidths, the contrast degradation caused by acid diffusion in the resist composition becomes more severe. This is because the pattern size is close to the diffusion length of the acid, leading to a decrease in mask fidelity and a deterioration in pattern rectangularity due to the increased dimensional offset on the wafer relative to the mask dimensional offset (mask error factor (MEF)). Therefore, to fully realize the benefits of shorter wavelength and higher photosensitive element (NA) of the light source, it is necessary to increase the dissolution contrast of the known materials or suppress acid diffusion. As one improvement measure, reducing the baking temperature will reduce acid diffusion, which may improve the MEF, but will inevitably reduce its sensitivity.

[0008] Introducing bulky substituents and polar groups into photoacid generators is effective in suppressing acid diffusion. Patent Document 4 describes a photoacid generator with 2-acyloxy-1,1,3,3,3-pentafluoropropane-1-sulfonic acid, which exhibits excellent solvent solubility and stability and allows for flexible molecular design. In particular, the photoacid generator with 2-(1-adamantoxy)-1,1,3,3,3-pentafluoropropane-1-sulfonic acid, which incorporates 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. Although it has been confirmed that the introduction of polar groups leads to a certain degree of performance improvement in acid diffusion suppression, the degree of acid diffusion control remains insufficient to date. Considering factors such as MEF, pattern shape, and sensitivity, the photolithography performance is not satisfactory.

[0009] Introducing polar groups into the anion of the photoacid generator is effective in suppressing acid diffusion, but it is disadvantageous from the viewpoint of solvent solubility. Patent documents 8 and 9 have attempted to improve solvent solubility by introducing alicyclic groups into the cationic portion of the photoacid generator, specifically cyclohexane and adamantane rings. While the introduction of such alicyclic groups improves solubility, a certain number of carbon atoms is required to ensure solubility, resulting in a larger molecular structure of the photoacid generator. Consequently, when forming fine patterns, photolithographic properties such as linewidth roughness (LWR) and dimensional uniformity (CDU) deteriorate.

[0010] Furthermore, Patent Document 10 describes a photoacid generator that produces fluoroalkyl sulfonic acid by having an aromatic condensation ring derived from anthracene in the anion. While this has been confirmed to improve photolithography performance to some extent, the alkyl sulfonic acid structure lacks rigidity, and there are concerns about the environmental and human health effects due to the increasing regulatory restrictions on organofluorine compounds that are targets of PFAS in recent years.

[0011] Iodine atoms exhibit significant absorption at a wavelength of 13.5 nm in EUV, thus it has been confirmed that they generate secondary electrons during exposure, attracting attention in EUV lithography. Patent documents 11 and 12 describe photoacid generators with anionicly introduced iodine atoms, while patent document 13 describes a photoacid generator containing polymerizable groups with anionicly introduced iodine atoms. Patent document 14 describes a photoacid generator with both cationic and anionic introduced iodine atoms. While these methods have been shown to improve lithography performance to some extent, the organic solvent solubility of iodine atoms is not high, raising concerns about precipitation in solvents.

[0012] Patent document 15 describes a photoacid generator in which multiple fluorine atoms are introduced into the cation. Although the introduction of multiple fluorine atoms improves the solvent solubility of the photoacid generator, it is still insufficient from the perspective of EUV absorption, leaving room for improvement.

[0013] Patent documents 16-20 describe photoacid generators and quenchers (acid diffusion control agents) containing iodine and fluorine atoms in their cationic forms. While these developments have confirmed improvements in the performance of photoresist materials, the viewpoint on acid diffusion control remains unsatisfactory, and there is a demand for developing photoresist materials that are more useful in the formation of fine patterns.

[0014] Existing technical documents

[0015] Patent documents

[0016] [Patent Document 1] Japanese Patent Application Publication No. 2008-281974

[0017] [Patent Document 2] Japanese Patent Application Publication No. 2008-281975

[0018] [Patent Document 3] Japanese Patent No. 4554665

[0019] [Patent Document 4] Japanese Patent Application Publication No. 2007-145797

[0020] [Patent Document 5] Japanese Patent No. 5061484

[0021] [Patent Document 6] Japanese Patent Application Publication No. 2016-147879

[0022] [Patent Document 7] Japanese Patent Application Publication No. 2015-63472

[0023] [Patent Document 8] Japanese Patent No. 5573098

[0024] [Patent Document 9] Japanese Patent No. 6461919

[0025] [Patent Document 10] Japanese Patent No. 7109178

[0026] [Patent Document 11] Japanese Patent No. 6720926

[0027] [Patent Document 12] International Publication No. 2024 / 057701

[0028] [Patent Document 13] Japanese Patent No. 6973274

[0029] [Patent Document 14] Japanese Patent No. 7041204

[0030] [Patent Document 15] Japanese Patent No. 7389562

[0031] [Patent Document 16] Japanese Patent Application Publication No. 2021-123579

[0032] [Patent Document 17] Japanese Patent Application Publication No. 2021-123580

[0033] [Patent Document 18] Japanese Patent Application Publication No. 2022-123839

[0034] [Patent Document 19] Japanese Patent Application Publication No. 2023-88869

[0035] [Patent Document 20] Japanese Patent Application Publication No. 2023-88870

[0036] Non-patent literature

[0037] [Non-patent literature 1] Journal of Photopolymer Science and Technology, Vol.17, No.4, pp.587-601 (2004) Summary of the Invention

[0038] [The problem that the invention aims to solve]

[0039] In response to the high resolution requirements of resist patterns in recent years, resist compositions using known onium salt-type photoacid generators cannot adequately suppress acid diffusion, resulting in deterioration of lithographic performance such as contrast, LWR, CDU, MEF, exposure latitude (EL), and depth of focus (DOF).

[0040] The present invention was made in view of the foregoing circumstances, and aims to provide an onium salt used in a chemical amplifying resist composition that exhibits excellent solvent solubility, high sensitivity, high contrast, and excellent lithographic performance such as LWR, CDU, MEF, EL, and DOF, particularly in optical lithography using high-energy rays such as KrF excimer lasers, ArF excimer lasers, electron beams (EB), and EUV; a chemical amplifying resist composition containing the onium salt as a photoacid generator; and a pattern formation method using the chemical amplifying resist composition.

[0041] [Methods for solving the problem]

[0042] The inventors of this application, through repeated and in-depth exploration in order to achieve the aforementioned objectives, have obtained the following insights, and thus completed this invention: Onion salts having an aromatic sulfonate anion with an acid-instable group and an iodine atom on an aromatic ring but without a fluorine atom have excellent solvent solubility, and chemical amplification resist compositions using them as photoacid generators have high sensitivity and high contrast, are extremely effective in suppressing acid diffusion, and have excellent photolithography properties such as LWR, CDU, MEF, EL, and DOF, and are extremely effective in forming fine patterns.

[0043] That is, the present invention provides the following onium salt, chemically amplified resist composition and pattern formation method.

[0044] 1. A kind of onium salt, represented by the following formula (1).

[0045] [Chemistry 1]

[0046]

[0047] In the formula, n1 is 0 or 1. n2 is 1, 2, 3 or 4. n3 is 1 or 2. n4 is 0, 1 or 2. However, when n1 is 0, 2≤n2+n3+n4≤5, and when n1 is 1, 2≤n2+n3+n4≤7.

[0048] LA It is an ether bond or an ester bond.

[0049] R AL It is an acid-labile group.

[0050] R 1 It can be a halogen atom other than fluorine and iodine atoms, a nitro group, 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, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. When n4 is 2, there are 2 R groups. 1 They can be the same or different, and there are 2 Rs. 1 They can also bond to each other and form rings together with the carbon atoms they are bonded to.

[0051] Z + It is a ium cation.

[0052] 2. Onium salts as in 1, wherein R AL It is an acid-instable group represented by the following formula (AL-1) or (AL-2).

[0053] [Chemistry 2]

[0054]

[0055] In the formula, R L1 R L2 and R L3 Each group is independently a hydrocarbon group having 1 to 12 carbon atoms, and a portion of the -CH2- group may be substituted with -O- or -S-. When the hydrocarbon group contains an aromatic ring or multiple bonds, a portion or all of the hydrogen atoms in the aromatic ring or multiple bonds may be substituted with a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 4 carbon atoms that may also contain a halogen atom, or an alkoxy group having 1 to 4 carbon atoms that may also contain a halogen atom. Furthermore, R... L1 and R L2 They can also bond with each other to form a ring, and a portion of the -CH2- in this ring can be replaced by -O- or -S-. However, R L3 When R does not contain any of the following: alicyclic structure, aromatic ring, or multiple bonds, L1 and R L2 They bond together to form a ring, and a portion of the -CH2- in the ring can be replaced by -O- or -S-.

[0056] R L4 and R L5 Each can be independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R L6 It is a hydrocarbon group with 1 to 20 carbon atoms, and part of the -CH2- group can be replaced by -O- or -S-. Also, R L5 and R L6 They can also bond to each other and to the carbon atoms and L atoms they are bonded to.B Together they form a heterocyclic group with 3 to 20 carbon atoms, and part of the -CH2- of the heterocyclic group can also be replaced by -O- or -S-.

[0057] L B It can be either -O- or -S-.

[0058] * indicates an atomic bond with an adjacent oxygen atom.

[0059] 3. Onium salts such as 1. or 2, which are represented by the following formula (1A).

[0060] [Chemistry 3]

[0061]

[0062] In the formula, n2, n4, L A R AL R 1 and Z + Same as above.

[0063] 4. Onium salts such as any one of 1. to 3, where Z + It is a sulfonium cation represented by formula (Z-1) or a monazine cation represented by formula (Z-2).

[0064] [Chemistry 4]

[0065]

[0066] In the formula, R ct1 ~R ct5 Each group is a hydrocarbon group with 1 to 30 carbon atoms, which may be independently composed of halogen atoms or may also contain heteroatoms. Also, R ct1 and R ct2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to.

[0067] 5. An onium salt as described in any of 1. to 3, wherein Z + The sulfonium cation is represented by the following formula (Z-3).

[0068] [Chemistry 5]

[0069]

[0070] In the formula, m1 is 0 or 1. m2 is 0 or 1. m3 is 0 or 1. m4 is 0, 1, 2, 3, or 4. m5 is 0, 1, 2, 3, or 4. m6 is 0, 1, 2, 3, 4, 5, or 6. m7 is 0, 1, 2, 3, 4, 5, or 6. m8 is 0, 1, or 2. m9 is 0, 1, or 2. m10 is 0, 1, or 2. m11 is 0 or 1. m12 is 0, 1, 2, 3, or 4. m13 is 0, 1, or 2. m14 is 0, 1, or 2. 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, 1 ≤ 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. Also, m4 + m12 ≥ 1.

[0071] R F1 ~R F3 Each R is independently a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms with an oxygen atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms with a thio group. When m5 is 2 or more, each R F1 They can be the same or different. When m6 is 2 or more, each R... F2 They can be the same or different. When m7 is 2 or more, each R... F3 They can be the same or different.

[0072] R ct6 ~R ct9 It can be a halogen atom other than iodine and fluorine atoms, a nitro group, a cyano 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 m8 is 2, there are 2 R groups. ct6 They can be the same or different, and there are 2 Rs. ct6 They can also 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, and there are 2 Rs. ct7 They can also bond to each other and form rings together with the carbon atoms they are bonded to. When m10 is 2, the two R atoms... ct8 They can be the same or different, and there are 2 Rs. ct8 They can also 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, and there are 2 Rs. ct9 They can also bond to each other and form rings together with the carbon atoms they are bonded to.

[0073] Furthermore, S directly bonded to the sulfonium cation +The aromatic rings can also bond with each other and with S + Together they form a ring.

[0074] 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.

[0075] X L It is a single bond, or may contain a heteroatom and a hydrocarbon group with 1 to 40 carbon atoms.

[0076] 6. Onium salts as in 5, wherein the sulfonium cation represented by formula (Z-3) is represented by formula (Z-3-1).

[0077] [Chemistry 6]

[0078]

[0079] In the formula, m4~m10, m12~m14, R F1 ~R F3 R ct6 ~R ct9 L C L D and X L Same as above.

[0080] 7. Onium salts as in 6, wherein the sulfonium cation represented by formula (Z-3-1) is represented by formula (Z-3-2).

[0081] [Chemistry 7]

[0082]

[0083] In the formula, m4~m10, R F1 ~R F3 and R ct6 ~R ct8 Same as above.

[0084] 8. A photoacid generator, comprising an onium salt of any one of 1. to 7.

[0085] 9. A chemically amplified resist composition containing a photoacid generator such as 8.

[0086] 10. The chemically amplified resist composition of 9. further contains a base polymer containing repeating units represented by the following formula (a1) or (a2).

[0087] [Chemistry 8]

[0088]

[0089] In the formula, RA Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0090] X 1 It is a single bond, phenylene, naphthylene, or *-C(=O)-OX 11 - and the phenylene or naphthylene group may also be replaced by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group with 1 to 10 carbon atoms containing a fluorine atom, or a saturated hydrocarbon group with 1 to 10 carbon atoms containing a fluorine atom, or a halogen atom. X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring.

[0091] X 2 It is a single bond or *-C(=O)-O-.

[0092] * indicates an atomic bond with a carbon atom in the main chain.

[0093] R 11 It 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 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. When a1 is 2, 3, or 4, each R 11 They can be the same or different.

[0094] AL 1 and AL 2 Each is an acid-labile group.

[0095] a1 can be 0, 1, 2, 3 or 4.

[0096] 11. A chemically amplified resist composition as described in 10, wherein the aforementioned base polymer contains repeating units represented by the following formula (a3).

[0097] [Chemistry 9]

[0098]

[0099] In the formula, b1 is 0 or 1. b2 is 0, 1, 2 or 3 when b1 is 0, and 0, 1, 2, 3, 4 or 5 when b1 is 1.

[0100] R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0101] X 3 It represents a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond with a carbon atom in the main chain.

[0102] X 4 It is a single bond, an aliphatic alkylene group, carbonyl group, sulfonyl group, or a combination thereof, having 1 to 4 carbon atoms.

[0103] 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 the adjacent carbon atom of the aromatic ring.

[0104] R 12 and R 13 Each group consists independently of a hydrogen atom, or may contain heteroatoms, and is a hydrocarbon group with 1 to 20 carbon atoms. Also, R 12 and R 13 They can also bond to each other and form rings together with the carbon atoms they are bonded to.

[0105] R 14 It can be a halogen atom, hydroxyl group, cyano group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; it can also be a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms; it can also be a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon thio group or -N(R) group with 1 to 20 carbon atoms containing heteroatoms. 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 Multiple Rs can be the same or different. 14 They can also bond to each other and form rings together with the carbon atoms of the aromatic rings they are bonded to.

[0106] 12. A chemically amplified resist composition as in 10 or 11, wherein the aforementioned base polymer contains repeating units represented by formula (b1) or (b2).

[0107] [Chemistry 10]

[0108]

[0109] In the formula, R A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0110] Y 1 It represents a single bond or *-C(=O)-O-. * indicates an atomic bond with a carbon atom in the main chain.

[0111] R 21It 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)-).

[0112] R 22 It 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. When c2 is 2, 3, or 4, each R 22 They can be the same or different.

[0113] c1 can be 1, 2, 3, or 4. c2 can be 0, 1, 2, 3, or 4. However, 1 ≤ c1 + c2 ≤ 5.

[0114] 13. A chemically amplified resist composition as described in any one of 10 to 12, wherein the aforementioned base polymer contains at least one repeating unit selected from the following formula (c1), the following formula (c2), the following formula (c3), the following formula (c4), and the following formula (c5).

[0115] [Chemistry 11]

[0116]

[0117] In the formula, d1 and d2 are 0, 1, 2 or 3 independently, respectively.

[0118] 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.

[0119] R A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0120] Z 1 It is a single bond or may have substituents.

[0121] Z 2 For single bonds, **-C(=O)-OZ 21 -、**-C(=O)-NH-Z 21 -or**-OZ 21 -. Z 21It is an aliphatic alkylene group, phenylene group, or a divalent group obtained by combining them, having 1 to 6 carbon atoms, and may also contain halogen atoms, carbonyl groups, ester bonds, ether bonds, or hydroxyl groups.

[0122] Z 3 It can be a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond.

[0123] Z 4 It is a single bond, or an aliphatic alkylene group with 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may also contain halogen atoms, carbonyl groups, ester bonds, ether bonds, or hydroxyl groups.

[0124] 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 alkylene group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the aliphatic alkylene group may also contain halogen atoms, hydroxyl groups, ether bonds, ester bonds, or lactone rings.

[0125] Z 6 It can be a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond.

[0126] 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 heteroatoms and alkylene groups with 1 to 20 carbon atoms.

[0127] Z 8 Each is independently a single bond, ****-Z 81 -C(=O)-O-、****-C(=O)-NH-Z 81 -or ****-OZ 81 -. Z 81 It may also contain heteroatoms and alkylene groups with 1 to 20 carbon atoms.

[0128] 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 91It is an aliphatic alkylene group, phenylene, fluorinated phenylene, or phenylene substituted with trifluoromethyl, having 1 to 6 carbon atoms, and may also contain a carbonyl group, ester bond, ether bond, or hydroxyl group.

[0129] * indicates an atomic bond with a carbon atom in the main chain. ** indicates an atomic bond with Z. 1 The atomic bonds. *** indicates the relationship between Z and 6 Atomic bonds. **** represents the bond between Z and Z. 7 Atomic bonds.

[0130] L 1 It can be a single bond, ether bond, ester bond, carbonyl group, sulfonate bond, sulfonamide bond, carbonate bond or carbamate bond.

[0131] Rf 1 and Rf 2 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0132] 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.

[0133] Rf 5 and Rf 6 Each can be 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 It cannot be both hydrogen atoms at the same time.

[0134] 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 alkoxy group having 1 to 6 carbon atoms.

[0135] R 31 and R 32 Each can be independently a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. Also, R 31 and R 32 They can also bond to each other and form rings together with the sulfur atoms they are bonded to.

[0136] R 33 It is a halogen atom other than fluorine, or may contain a hydrocarbon group with 1 to 20 carbon atoms and heteroatoms. When e3 is 2, 3, or 4, each R 33 Multiple Rs can be the same or different. 33 They can also bond to each other and form rings together with the carbon atoms they are bonded to.

[0137] M - It is a non-nucleophilic relative ion.

[0138] A + It is a ium cation.

[0139] 14. Any chemically amplified resist composition as described in any of items 9 to 13, further contains organic solvents.

[0140] 15. Any chemically amplified resist composition as described in any of items 9 to 14, further contains a quenching agent.

[0141] 16. The chemically amplified resist composition of any one of 9 to 15, further contains a photoacid generating agent other than the photoacid generating agent of 8.

[0142] 17. Any chemically amplified resist composition as described in any of 9 to 16, further contains a surfactant.

[0143] 18. A method for forming a pattern, comprising the following steps:

[0144] A resist film is formed on a substrate using a chemically amplified resist composition as described in any one of 9. to 17, and the aforementioned resist film is exposed to high-energy radiation.

[0145] The previously exposed resist film was developed using a developer.

[0146] 19. The pattern forming method as in 18, wherein the aforementioned high-energy rays are KrF excimer lasers, ArF excimer lasers, EB, or EUV with a wavelength of 3 to 15 nm.

[0147] [The effects of the invention]

[0148] When patterning is performed using a chemically amplified resist composition containing the onium salt of the present invention as a photoacid generator, it exhibits high sensitivity, excellent acid diffusion suppression capability, and can improve the lithography performance of LWR, CDU, MEF, EL, DOF, etc., and can suppress the collapse of resist patterns during the formation of fine patterns. Detailed Implementation

[0149] The present invention will now be described in detail. Furthermore, in the following description, the structure represented by the chemical formula may contain asymmetric carbon, and mirror-image isomers and non-mirror-image isomers may exist; in such cases, each isomer is represented by a single formula. These isomers may be used individually or in mixtures of two or more.

[0150] [Salt]

[0151] The onium salt of the present invention is represented by the following formula (1).

[0152] [Chemistry 12]

[0153]

[0154] 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. Considering solvent solubility, it is preferable to have a benzene ring with n1 = 0. n2 is 1, 2, 3, or 4. n3 is 1 or 2. Considering the availability of raw materials, n3 is preferably 1. n4 is 0, 1, or 2. Considering the availability of raw materials, n4 is preferably 0 or 1, with 0 being better. However, when n1 is 0, 2 ≤ n2 + n3 + n4 ≤ 5; when n1 is 1, 2 ≤ n2 + n3 + n4 ≤ 7.

[0155] In equation (1), L A The R group is considered to be an ether or ester bond, and is an acid-labile group. AL The viewpoint on the affinity of the departing polar groups for alkaline developing solutions, L A It should be an ester bond.

[0156] In equation (1), R 1 The halogen atom other than fluorine and iodine atoms, a nitro group, a hydrocarbon group with 1 to 20 carbon atoms (which may also contain heteroatoms), a hydrocarbon group with 1 to 20 carbon atoms (which may also contain heteroatoms), or a hydrocarbon group with 1 to 20 carbon atoms (which may also contain heteroatoms) or a hydrocarbon group with 1 to 20 carbon atoms (which may also contain heteroatoms) or a thio group. Examples of halogen atoms other than fluorine and iodine atoms include chlorine atoms and bromine atoms. The aforementioned hydrocarbon groups can be saturated or unsaturated, and can be linear, 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 these. Among these, aryl groups are preferred. 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 also be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. This can result in the presence of hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone, sulfonate, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc. When n4 is 2, there are 2 R groups. 1 They can be the same or different. Also, when n4 is 2, there are 2 R... 1They can also bond to each other and form rings together with the carbon atoms they are bonded to. The aforementioned rings are preferably 5- to 8-membered rings.

[0157] In equation (1), R AL It is an acid-indestructible group. The aforementioned acid-indestructible group should preferably be represented by the following formula (AL-1) or (AL-2).

[0158] [Chemistry 13]

[0159]

[0160] In the formula, * represents an atomic bond with an adjacent oxygen atom.

[0161] In equation (AL-1), R L1 R L2 and R L3 Each is independently a hydrocarbon group having 1 to 12 carbon atoms, and a portion of the -CH2- group may be replaced by -O- or -S-. When the hydrocarbon group contains an aromatic ring or multiple bonds, a portion or all of the hydrogen atoms of the aromatic ring or multiple bonds may be replaced by a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 4 carbon atoms that may also contain a halogen atom, or an alkoxy group having 1 to 4 carbon atoms that may also contain a halogen atom.

[0162] R L1 R L2 and R L3 The hydrocarbon groups representing 1 to 12 carbon atoms can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, etc., alkyl groups representing 1 to 12 carbon atoms; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornel, norbornelmethyl, adamantyl, adamantylmethyl, tricyclic [5.2.1.0] 2,6 ] decyl, tetracyclic [6.2.1.1 3,6 .0 2,7 Cyclic saturated hydrocarbon groups with 3 to 12 carbon atoms, such as dodecyl; alkenyl groups with 2 to 12 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, pentenyl, and hexenyl; alkynyl groups with 2 to 12 carbon atoms, such as ethynyl, propynyl, butynyl, pentynyl, and hexynyl; cyclic unsaturated aliphatic hydrocarbon groups with 3 to 12 carbon atoms, such as cyclopentenyl and cyclohexenyl; aryl groups with 6 to 12 carbon atoms, such as phenyl, naphthyl, and dihydroindenyl; aralkyl groups with 7 to 12 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these groups.

[0163] Also, R L1 and RL2 They can also bond with each other to form a ring, and a portion of the -CH2- in this ring can be replaced by -O- or -S-. However, R L3 When R does not contain any of the following: alicyclic structure, aromatic ring, or multiple bonds, L1 and R L2 They bond together to form a ring, and part of the -CH2- in this ring can be replaced by -O- or -S-. Examples of rings formed include: cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclooctane ring, norbornene ring, adamantane ring, and tricyclic rings [5.2.1.0]. 2,6 Decane ring, tetracyclic ring [6.2.1.1] 3,6 .0 2,7 Dodecane ring, etc. Furthermore, a portion of the -CH2- group in the aforementioned rings can also be replaced by -O- or -S-.

[0164] In equation (AL-2), R L4 and R L5 Each can be independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R L4 and R L5 The hydrocarbon group representing 1 to 10 carbon atoms can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be given as R. L1 R L2 and R L3 The hydrocarbon group represents those with 1 to 10 carbon atoms.

[0165] In equation (AL-2), R L6 It is a hydrocarbon group with 1 to 20 carbon atoms, and part of the -CH2- of this hydrocarbon group may be replaced by -O- or -S-. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include: 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, eicosyl, etc., alkyl groups with 1 to 20 carbon atoms; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornel, norbornelmethyl, adamantyl, adamantylmethyl, tricyclic [5.2.1.0] 2,6 ] decyl, tetracyclic [6.2.1.1 3,6 .0 2,7[Cyclic saturated hydrocarbon groups with 3 to 20 carbon atoms, such as dodecyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, propynyl, butenyl, pentenyl, and hexenyl; alkynyl groups with 2 to 20 carbon atoms, such as ethynyl, propynyl, butynyl, pentynyl, and hexynyl; cyclic unsaturated aliphatic hydrocarbon groups with 3 to 20 carbon atoms, such as cyclopentenyl, cyclohexenyl, and norcamphenyl; aryl groups with 6 to 20 carbon atoms, such as phenyl, tolyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butenaphthyl, isobutenaphthyl, sec-butenaphthyl, and tert-butenaphthyl; aralkyl groups with 7 to 20 carbon atoms, such as benzyl and phenethyl; and groups formed by combining these groups. Also, R] L5 and R L6 They can also bond to each other and to the carbon atoms and L atoms they are bonded to. B Together they form a heterocyclic group with 3 to 20 carbon atoms, and part of the -CH2- of the heterocyclic group can also be replaced by -O- or -S-.

[0166] In equation (AL-2), L B It can be either -O- or -S-.

[0167] The unstable acid groups represented by formula (AL-1) can be listed below, but are not limited to. Additionally, in the following formula, * indicates an atomic bond with an adjacent oxygen atom.

[0168] [Chemistry 14]

[0169]

[0170] [Chemistry 15]

[0171]

[0172] [Chemistry 16]

[0173]

[0174] [Chemistry 17]

[0175]

[0176] [Chemistry 18]

[0177]

[0178] [Chemistry 19]

[0179]

[0180] [Chemistry 20]

[0181]

[0182] [Chemistry 21]

[0183]

[0184] [Chemistry 22]

[0185]

[0186] [Chemistry 23]

[0187]

[0188] [Chemistry 24]

[0189]

[0190] The acid-instable groups represented by formula (AL-2) can be listed below, but are not limited to. Additionally, in the following formula, * indicates an atomic bond with an adjacent -O-.

[0191] [Chemistry 25]

[0192]

[0193] [Chemistry 26]

[0194]

[0195] The onium salt represented by formula (1) should preferably be represented by the following formula (1A).

[0196] [Chemistry 27]

[0197]

[0198] In the formula, n2, n4, L A R AL R 1 and Z + Same as above.

[0199] Specific examples of the anions of onium salts represented by formula (1) are shown below, but are not limited thereto. In addition, Me is a methyl group in the following formula.

[0200] [Chemistry 28]

[0201]

[0202] [Chemistry 29]

[0203]

[0204] [Chemistry 30]

[0205]

[0206] [Chemistry 31]

[0207]

[0208] [Chemistry 32]

[0209]

[0210] [Chemistry 33]

[0211]

[0212] [Chemistry 34]

[0213]

[0214] [Chemistry 35]

[0215]

[0216] [Chemistry 36]

[0217]

[0218] [Chemistry 37]

[0219]

[0220] [Chemistry 38]

[0221]

[0222] [Chemistry 39]

[0223]

[0224] [Chemistry 40]

[0225]

[0226] [Chemistry 41]

[0227]

[0228] [Chemistry 42]

[0229]

[0230] [Chemistry 43]

[0231]

[0232] [Chemistry 44]

[0233]

[0234] [Chemistry 45]

[0235]

[0236] [Chemistry 46]

[0237]

[0238] [Chemistry 47]

[0239]

[0240] [Chemistry 48]

[0241]

[0242] [Chemistry 49]

[0243]

[0244] [Transformation 50]

[0245]

[0246] [Chemistry 51]

[0247]

[0248] [Chemistry 52]

[0249]

[0250] [Chemistry 53]

[0251]

[0252] [Chemistry 54]

[0253]

[0254] [Chemistry 55]

[0255]

[0256] [Chemistry 56]

[0257]

[0258] [Chemistry 57]

[0259]

[0260] [Chem.58]

[0261]

[0262] [Chemistry 59]

[0263]

[0264] [Transformation 60]

[0265]

[0266] [Chemistry 61]

[0267]

[0268] [Chemistry 62]

[0269]

[0270] [Chemistry 63]

[0271]

[0272] [Chemistry 64]

[0273]

[0274] [Chemistry 65]

[0275]

[0276] [Chemistry 66]

[0277]

[0278] [Chemistry 67]

[0279]

[0280] [Chemistry 68]

[0281]

[0282] [Chemistry 69]

[0283]

[0284] [Chemistry 70]

[0285]

[0286] [Chemistry 71]

[0287]

[0288] [Chemistry 72]

[0289]

[0290] [Chemistry 73]

[0291]

[0292] [Chemistry 74]

[0293]

[0294] [Chemistry 75]

[0295]

[0296] [Chemistry 76]

[0297]

[0298] [Chemistry 77]

[0299]

[0300] [Chemistry 78]

[0301]

[0302] [Chemistry 79]

[0303]

[0304] [Chemistry 80]

[0305]

[0306] [Chemistry 81]

[0307]

[0308] [Chemistry 82]

[0309]

[0310] [Chemistry 83]

[0311]

[0312] [Chemistry 84]

[0313]

[0314] [Chemistry 85]

[0315]

[0316] [Chemistry 86]

[0317]

[0318] [Chemistry 87]

[0319]

[0320] [Chemistry 88]

[0321]

[0322] [Chemistry 89]

[0323]

[0324] [Chemistry 90]

[0325]

[0326] [Chemistry 91]

[0327]

[0328] [Chemistry 92]

[0329]

[0330] [Chemistry 93]

[0331]

[0332] [Chemistry 94]

[0333]

[0334] [Chemistry 95]

[0335]

[0336] [Chemistry 96]

[0337]

[0338] [Chemistry 97]

[0339]

[0340] [Chem. 98]

[0341]

[0342] [Chemistry 99]

[0343]

[0344] [Chemistry 100]

[0345]

[0346] [Chemistry 101]

[0347]

[0348] [Chemistry 102]

[0349]

[0350] [Chemistry 103]

[0351]

[0352] [Chemistry 104]

[0353]

[0354] [Chemistry 105]

[0355]

[0356] [Chemistry 106]

[0357]

[0358] [Chemistry 107]

[0359]

[0360] [Chemistry 108]

[0361]

[0362] [Chemistry 109]

[0363]

[0364] [Chemical 110]

[0365]

[0366] [Chemistry 111]

[0367]

[0368] [Chemistry 112]

[0369]

[0370] [Chemistry 113]

[0371]

[0372] [Chemistry 114]

[0373]

[0374] [Chemistry 115]

[0375]

[0376] [Chemistry 116]

[0377]

[0378] [Chemistry 117]

[0379]

[0380] [Chemistry 118]

[0381]

[0382] [Chemistry 119]

[0383]

[0384] [Chemistry 120]

[0385]

[0386] [Chemistry 121]

[0387]

[0388] [Chemistry 122]

[0389]

[0390] [Chemistry 123]

[0391]

[0392] [Chemistry 124]

[0393]

[0394] [Chemistry 125]

[0395]

[0396] [Chemistry 126]

[0397]

[0398] [Chemistry 127]

[0399]

[0400] [Chemistry 128]

[0401]

[0402] [Chemistry 129]

[0403]

[0404] [Chemistry 130]

[0405]

[0406] [Chemistry 131]

[0407]

[0408] [Chemistry 132]

[0409]

[0410] [Chemistry 133]

[0411]

[0412] In equation (1), Z + The aforementioned onium cation is preferably a sulfonium cation represented by formula (Z-1) or a sulfonium cation represented by formula (Z-2).

[0413] [Chemistry 134]

[0414]

[0415] In equations (Z-1) and (Z-2), R ct1 ~R ct5 Each is a hydrocarbon group with 1 to 30 carbon atoms, which may be independently composed of halogen atoms or may contain heteroatoms.

[0416] R ct1 ~R ct5 Specific examples of halogen atoms that can be represented include: fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.

[0417] R ct1 ~R ct5The hydrocarbon group represented can be saturated or unsaturated, and can be linear, 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, norcamphenyl, 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 groups, which should preferably be aryl. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group may be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- in the aforementioned hydrocarbon group may also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0418] Also, R ct1 and R ct2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to. Specific examples of the aforementioned ring structures can be shown in the following formulas, etc.

[0419] [Chemistry 135]

[0420]

[0421] In the formula, the dashed line represents R. ct3 Atomic bonds.

[0422] Specific examples of sulfonium cations represented by formula (Z-1) can be found in paragraphs

[0102] to

[0125] of Japanese Patent Application Publication No. 2024-003744, but are not limited thereto.

[0423] Specific examples of citric acid represented by formula (Z-2) can be found in paragraph

[0181] of Japanese Patent Application Publication No. 2024-000259, but are not limited thereto.

[0424] Z + The onium cation represented should also be the sulfonium cation represented by the following formula (Z-3).

[0425] [Chemistry 136]

[0426]

[0427] 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. Considering solvent solubility, it is preferable to have a benzene ring with m1 = 0. m2 is 0 or 1. When m2 is 0, it is a benzene ring; when m2 is 1, it is a naphthalene ring. Considering solvent solubility, it is preferable to have a benzene ring with m2 = 0. m3 is 0 or 1. When m3 is 0, it is a benzene ring; when m3 is 1, it is a naphthalene ring. Considering solvent solubility, it is preferable to have a benzene ring with m3 = 0.

[0428] 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, especially. However, due to concerns about precipitation in the resist composition due to insufficient solvent solubility, m4 is preferably 0, 1, 2, or 3, with 0, 1, or 2 being more desirable.

[0429] In formula (Z-3), m5 can be 0, 1, 2, 3, or 4. Considering the availability of raw materials, m5 is preferably 0, 1, 2, or 3, with 0, 1, or 2 being more preferred. m6 can be 0, 1, 2, 3, 4, 5, or 6. Considering the availability of raw materials, m6 is preferably 0, 1, 2, or 3, with 0, 1, or 2 being more preferred. m7 can be 0, 1, 2, 3, 4, 5, or 6. Considering the availability of raw materials, m7 is preferably 0, 1, 2, or 3, with 0, 1, or 2 being more preferred.

[0430] In formula (Z-3), m8 is 0, 1, or 2. Considering the availability of raw materials, m8 should preferably be 0 or 1. m9 is 0, 1, or 2. Considering the availability of raw materials, m9 should preferably be 0 or 1. m10 is 0, 1, or 2. Considering the availability of raw materials, m10 should preferably be 0 or 1.

[0431] 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. Considering solvent solubility, it is preferable to have a benzene ring with m11 of 0.

[0432] 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, especially. However, due to concerns about precipitation in the resist composition due to insufficient solvent solubility, m12 is preferably 0, 1, 2, or 3, with 0, 1, or 2 being more preferred.

[0433] In equation (Z-3), m13 is 0, 1, or 2. From the perspective of raw material availability, m13 should preferably be 0 or 1. m14 is 0, 1, or 2. From a synthetic perspective, m14 should preferably be 0 or 1.

[0434] 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, 1 ≤ 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. Also, m4 + m12 ≥ 1.

[0435] In equation (Z-3), R F1 ~R F3 Each R is independently a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Among these, trifluoromethyl, trifluoromethoxy, and trifluorothiomethoxy are preferred. When m5 is 2 or more, each R... F1 They can be the same or different. When m6 is 2 or more, each R... F2 They can be the same or different. When m7 is 2 or more, each R... F3 They can be the same or different.

[0436] In equation (Z-3), R ct6 ~R ct9 The hydroxyl group can be a halogen atom other than iodine or fluorine, a nitro group, a cyano group, 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, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. The hydrocarbon group, hydrocarbon oxygen group, and hydrocarbon thio group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed and illustrated in the description of formula (1) as R. 1 The same example applies to the hydrocarbon group. Furthermore, some or all of the hydrogen atoms in the hydrocarbon group, hydrocarbon oxygen group, and hydrocarbon sulfide group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. Also, a portion of the -CH2- group in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may 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.

[0437] Also, when m8 is 2, there are 2 Rs. ct6 They can be the same or different, and there are 2 Rs. ct6 They can also 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, and there are 2 Rs. ct7They can also bond to each other and form rings together with the carbon atoms they are bonded to. When m10 is 2, the two R atoms... ct8 They can be the same or different, and there are 2 Rs. ct8 They can also 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, and there are 2 Rs. ct9 They can also bond with each other and form rings together with the carbon atoms they are bonded to. Specific examples of rings formed in this case include: cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the -CH2- in the aforementioned rings can also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, they may 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.

[0438] Furthermore, formula (Z-3) represents the S directly bonded to the sulfonium cation. + The aromatic rings can also bond with each other and with S + Together they form a ring. Specific examples of the aforementioned ring structure can be exemplified by the following formulas, etc.

[0439] [Chemistry 137]

[0440]

[0441] In the formula, the dashed lines represent atomic bonds.

[0442] In equation (Z-3), L C and L D These can be independently identified as single bonds, ether bonds, ester bonds, amide bonds, sulfonate bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Among them, L... C The bonds should ideally be single bonds, ether bonds, ester bonds, or sulfonate bonds, with ester bonds or sulfonate bonds being more preferred. D It is preferable to have a single bond, ether bond, or ester bond, with a single bond being better.

[0443] In equation (Z-3), X L It is a single bond, or may contain heteroatoms, of carbon atoms ranging from 1 to 40. The aforementioned alkylene group can be linear, branched, or cyclic; specific examples include alkyldiyl, cyclic saturated alkylene groups, and arylene groups. Specific examples of the aforementioned heteroatoms include oxygen atoms, nitrogen atoms, and sulfur atoms.

[0444] X LExamples of hydrocarbon groups containing 1 to 40 carbon atoms that may also contain heteroatoms are shown below, but are not limited to these. Additionally, in the following formula, * indicates that they are related to L... C and L D Atomic bonds.

[0445] [Chemistry 138]

[0446]

[0447] [Chemistry 139]

[0448]

[0449] [Chemistry 140]

[0450]

[0451] [Chemistry 141]

[0452]

[0453] Among them, X is the most suitable. L -0~X L -22, X L -29~X L -34, and X L -47~X L -58.

[0454] The sulfonium cation represented by formula (Z-3) should preferably be represented by the following formula (Z-3-1).

[0455] [Chemistry 142]

[0456]

[0457] In the formula, m4~m10, m12~m14, R F1 ~R F3 R ct6 ~R ct9 L C L D and X L Same as above. The sulfonium cation represented by formula (Z-3-1) should preferably be represented by formula (Z-3-2).

[0458] [Chemistry 143]

[0459]

[0460] In the formula, m4~m10, R F1 ~R F3 and R ct6 ~R ct8 Same as above.

[0461] Specific examples of sulfonium cations represented by formula (Z-3) are shown below, but are not limited thereto. Additionally, in the following formula, Me is a methyl group.

[0462] [Chemistry 144]

[0463]

[0464] [Chemistry 145]

[0465]

[0466] [Chemistry 146]

[0467]

[0468] [Chemistry 147]

[0469]

[0470] [Chemistry 148]

[0471]

[0472] [Chemistry 149]

[0473]

[0474] [Chemistry 150]

[0475]

[0476] [Chemistry 151]

[0477]

[0478] [Chemistry 152]

[0479]

[0480] [Chemistry 153]

[0481]

[0482] [Chemistry 154]

[0483]

[0484] [Chemistry 155]

[0485]

[0486] [Chemistry 156]

[0487]

[0488] [Chemistry 157]

[0489]

[0490] [Chemistry 158]

[0491]

[0492] [Chemistry 159]

[0493]

[0494] [Chemistry 160]

[0495]

[0496] [Chemistry 161]

[0497]

[0498] [Chemistry 162]

[0499]

[0500] [Chemistry 163]

[0501]

[0502] [Chemistry 164]

[0503]

[0504] [Chemistry 165]

[0505]

[0506] [Chemistry 166]

[0507]

[0508] [Chemistry 167]

[0509]

[0510] [Chemistry 168]

[0511]

[0512] [Chemistry 169]

[0513]

[0514] [Chemistry 170]

[0515]

[0516] [Chemistry 171]

[0517]

[0518] Specific examples of the onium salts of the present invention can be listed as any combination of the aforementioned anions and cations.

[0519] The ononium salts of the present invention can be synthesized using known methods. For example, a method for manufacturing an ononium salt represented by the following formula (PAG-1-ex) will be described, but the synthesis method is not limited thereto.

[0520] [Chemistry 172]

[0521]

[0522] In the formula, R 1 R L1 R L2 R L3 n1, n2, n4 and Z + Same as above. M + It is an alkali metal cation or an alkaline earth metal cation. A - For anions.

[0523] Step 1 involves reacting commercially available or known synthetic starting material SM-1 with starting material SM-2 to obtain intermediate In-1. Intermediate In-1 is synthesized by a ring-opening reaction using the hydroxyl group of starting material SM-2, targeting the anhydrides of the formic acid and sulfonic acid dehydration structures of starting material SM-1. During the ring-opening reaction, since starting material SM-2 is a tertiary alcohol, it is advisable to convert it to the corresponding metal alkoxide beforehand to improve reactivity. The metal alkoxide is prepared by reacting M... + H - Metal alkoxides are prepared by suspending alkali metal or alkaline earth metal hydrides in solvents such as THF and adding dropwise an alcoholic solution of the starting material SM-2. Examples of metal hydrides used include sodium hydride, potassium hydride, and calcium hydride, and other germinal reagents such as methyl magnesium chloride and ethyl magnesium chloride can be used for the preparation of metal alkoxides. For efficient preparation of metal alkoxides, the solvent temperature should be appropriately heated from approximately 50°C to the solvent's boiling point. After obtaining the metal alkoxide, the starting material SM-1 is added, and the reaction can be carried out by heating as needed. Ideally, the reaction time should be monitored by silica gel thin-layer chromatography (TLC) until completion, typically for about 4–12 hours, from a yield perspective. The intermediate In-1 can be obtained from the reaction mixture using a conventional aqueous work-up, and can be purified by conventional methods such as chromatography and recrystallization if necessary.

[0524] The second step is to make the obtained intermediates In-1 and Z + A - The step involves salt exchange of the indicated onium salt (raw material SM-3) to obtain the onium salt (PAG-1-ex). Additionally, A... - Considering the ease of quantitative exchange reactions, chloride, bromide, iodide, or methyl sulfate anions are preferred. Ideally, the reaction time should be monitored by TLC until completion, typically around 4–12 hours, for yield purposes. The onium salt (PAG-1-ex) can be obtained from the reaction mixture using a conventional aqueous work-up. Purification can be performed using common methods such as chromatography and recrystallization if necessary.

[0525] In the aforementioned process, the ion exchange in step 2 can be easily implemented using known methods, for example, Japanese Patent Application Publication No. 2007-145797.

[0526] Furthermore, the aforementioned manufacturing method is at most one example, and the manufacturing method of the onium salt of the present invention is not limited thereto.

[0527] The structural features of the onium salt of the present invention can be exemplified by the presence of an aromatic sulfonic acid structure with an iodine atom and an acid-indestabilized group on the aromatic ring. The iodine atom, being a large atomic weight element, can be used as a group to suppress acid diffusion. Furthermore, especially in EUV lithography at a wavelength of 13.5 nm, the iodine atom exhibits very high absorption of EUV, thus generating secondary electrons during exposure. In addition, due to its appropriate electron-withdrawing properties, the acidity of the generated acid is improved, promoting the deprotection reaction of the base polymer. On the other hand, the acid-indestabilized group undergoes a deprotection reaction due to the acid, generating a polar group composed of aromatic alcohols or aromatic carboxylic acids. By utilizing the deprotection reaction of the acid-indestabilized group on the onium salt after exposure, and combining it with the deprotection reaction of the base polymer, the solubility contrast can be improved. Iodine atoms are known to have low solvent solubility, but in the presence of acid-labile groups before exposure, they exhibit good solvent solubility due to their high lipid solubility. Furthermore, when the exposed area is developed with an alkaline developer after exposure, sulfonyl groups and the aforementioned polar groups are generated, resulting in good solubility in the alkaline developer and suppressing development defects in the exposed area. The unexposed area exhibits appropriate solubility inhibition due to the iodine atoms, thus showing resistance to alkaline developer and reducing resist pattern loss in the unexposed area, while also suppressing collapse. Utilizing these synergistic effects, the resist composition containing the onium salt of this invention has high sensitivity and low acid diffusion, resulting in excellent line pattern LWR, hole pattern CDU, and the formation of patterns with strong resistance to pattern collapse, making it ideal for fine pattern formation.

[0528] The aforementioned onium salts are ideally suited for use as photoacid generators.

[0529] [Chemical amplification resist composition]

[0530] [(A) Photoacid generator]

[0531] The chemically amplified resist composition of the present invention contains (A) a photoacid generator composed of an onium salt represented by formula (1) as an essential component.

[0532] In the chemically amplified resist composition of the present invention, the content of the photoacid generating agent composed of onium salt 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 aforementioned range, the sensitivity and resolution are good, and there is no concern about the generation of foreign matter in the resist film after development or during peeling, which is therefore ideal. One type of photoacid generating agent (A) can be used alone, or two or more can be used in combination.

[0533] [(B) Basic Polymer]

[0534] The chemically amplified resist composition of the present invention may also contain a base polymer as component (B). The base polymer (B) is a repeating unit represented by formula (a1) (hereinafter also referred to as repeating unit a1) or a repeating unit represented by formula (a2) (hereinafter also referred to as repeating unit a2).

[0535] [Chemistry 173]

[0536]

[0537] In equations (a1) and (a2), R A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0538] In equation (a1), X 1 It is a single bond, phenylene, naphthylene, or *-C(=O)-OX 11 - and the phenylene or naphthylene group may also be replaced by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group with 1 to 10 carbon atoms containing a fluorine atom, or a saturated hydrocarbon group with 1 to 10 carbon atoms containing a fluorine atom, or a halogen atom. X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group having 1 to 10 carbon atoms, and the saturated hydrocarbon group may also contain a hydroxyl group, ether bond, ester bond, or lactone ring. * indicates an atomic bond with a carbon atom in the main chain.

[0539] In equation (a2), X 2 It represents a single bond or *-C(=O)-O-. * indicates an atomic bond with a carbon atom in the main chain. R 11It 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 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. When a1 is 2, 3, or 4, each R 11 They can be the same or different. a1 can be 0, 1, 2, 3 or 4, and should preferably be 0 or 1.

[0540] In equations (a1) and (a2), AL 1 and AL 2 Each of these groups is an acid-indestructible group independently. Specific examples of the aforementioned acid-indestructible groups can be cited, for example, those described in Japanese Patent Application Publication No. 2013-80033 and Japanese Patent Application Publication No. 2013-83821.

[0541] For representativeness, specific examples of the aforementioned acid-instable groups can be listed as those represented by formulas (AL-3) to (AL-5).

[0542] [Chemistry 174]

[0543]

[0544] In the formula, * represents an atomic bond.

[0545] In equations (AL-3) and (AL-4), R L11 and R L12 Each hydrocarbon group is independently composed of 1 to 40 carbon atoms and may also contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The aforementioned hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. Preferably, the aforementioned hydrocarbon groups have 1 to 20 carbon atoms.

[0546] In formula (AL-3), a2 is an integer from 0 to 10, preferably 1, 2, 3, 4 or 5.

[0547] In equation (AL-4), R L13 and R L14 Each group is independently composed of a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and may also contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine. The aforementioned hydrocarbon groups can be saturated or unsaturated, and can be linear, branched, or cyclic. Furthermore, R... L12 R L13 and R L14 Any two atoms in the ring can also 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. The aforementioned ring is preferably a ring with 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0548] In equation (AL-5), R L15R L16 and R L17 Each group is an independent hydrocarbon group having 1 to 20 carbon atoms, and may also contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The aforementioned hydrocarbon groups can be saturated or unsaturated, and can be linear, branched, or cyclic. Furthermore, R... L15 R L16 and R L17 Any two atoms in the ring can also bond to each other and together with the carbon atoms they are bonded to form a ring with 3 to 20 carbon atoms. The aforementioned ring is preferably a ring with 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0549] Specific examples of repeated unit a1 can be listed below, but are not limited to these. Additionally, in the following formula, R... A and AL 1 Same as above.

[0550] [Chemistry 175]

[0551]

[0552] [Chemistry 176]

[0553]

[0554] [Chemistry 177]

[0555]

[0556] [Chemistry 178]

[0557]

[0558] Specific examples of repeated unit a2 can be listed below, but are not limited to these. Additionally, in the following formula, R... A and AL 2 Same as above.

[0559] [Chemistry 179]

[0560]

[0561] [Chemistry 180]

[0562]

[0563] [Chemistry 181]

[0564]

[0565] The aforementioned polymer may also contain repeating units represented by the following formula (a3) ​​(hereinafter also referred to as repeating unit a3).

[0566] [Chemistry 182]

[0567]

[0568] 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. Considering solvent solubility, it is preferable to have a benzene ring with b1 = 0. b2 is 0, 1, 2, or 3 when b1 is 0, and 0, 1, 2, 3, 4, or 5 when b1 is 1. Considering the availability of raw materials, b2 is preferably 0, 1, 2, or 3, with 0, 1, or 2 being more desirable.

[0569] In equation (a3), R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, hydrogen atom or methyl group are preferred, with hydrogen atom being even more desirable.

[0570] In equation (a3), X 3 The bonds are single bonds, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond with a carbon atom in the main chain. Among these, single bonds and *-C(=O)-O- are preferred, with single bonds being even better.

[0571] In equation (a3), X 4 It can be a single bond, an aliphatic alkylene group with 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a combination thereof. Among these, considering the availability of raw materials, a single bond, a carbonyl group, or a sulfonyl group is preferable; considering the polar groups formed after the reaction, a single bond or a carbonyl group is more preferred.

[0572] 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 Bonded to an adjacent carbon atom in the aromatic ring. X 5 and X 6 They can be the same or different; considering the perspective of reactivity, X 5 and X 6 All of them should be oxygen atoms.

[0573] In equation (a3), R 12 and R 13Each 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 linear, 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, 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 and naphthyl; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- in the aforementioned hydrocarbon group can also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may 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.

[0574] Also, R 12 and R 13 They can also bond with each other and form rings together with the carbon atoms they are bonded to. Specific examples of rings formed in this case include: cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the -CH2- in the aforementioned rings can also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, they may 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.

[0575] In equation (a3), R 14 It can be a halogen atom, hydroxyl group, cyano group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; it can also be a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms; it can also be a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon thio group or -N(R) group with 1 to 20 carbon atoms containing heteroatoms. 14A (R) 14B R 14Aand 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, with fluorine or iodine being more preferred. The hydrocarbon group, as well as the hydrocarbon oxy group, hydrocarbon oxycarbonyl group, and hydrocarbon thio group, can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed and illustrated as R. 12 and R 13 The same example applies to hydrocarbon 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, or halogen atoms, and a portion of the -CH2- group in the aforementioned hydrocarbon group can also be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. This results in the possible inclusion of hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone, sulopentazone, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc. When b2 is 2 or more, each R... 14 They can be the same or different.

[0576] Furthermore, when b2 is 2 or more, multiple R 14 They can also bond with 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 case include: cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the -CH2- in the aforementioned rings can also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, they may 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.

[0577] Specific examples of repeated unit a3 can be listed below, but are not limited to these. Additionally, in the following formula, R... A As mentioned above, Me is methyl. Furthermore, the bonding positions of the various substituents on the aromatic ring can be interchanged.

[0578] [Chemistry 183]

[0579]

[0580] [Chemistry 184]

[0581]

[0582] [Chemistry 185]

[0583]

[0584] [Chemistry 186]

[0585]

[0586] [Chemistry 187]

[0587]

[0588] [Chemistry 188]

[0589]

[0590] [Chemistry 189]

[0591]

[0592] [Chemistry 190]

[0593]

[0594] [Chemistry 191]

[0595]

[0596] [Chemistry 192]

[0597]

[0598] [Chemistry 193]

[0599]

[0600] [Chemistry 194]

[0601]

[0602] [Chemistry 195]

[0603]

[0604] [Chemistry 196]

[0605]

[0606] [Chemistry 197]

[0607]

[0608] [Chemistry 198]

[0609]

[0610] [Chemistry 199]

[0611]

[0612] [Chem.200]

[0613]

[0614] [Chemical Engineering 201]

[0615]

[0616] [Chemical Engineering 202]

[0617]

[0618] [Chemical Engineering 203]

[0619]

[0620] [Chemical 204]

[0621]

[0622] [Chemical Engineering 205]

[0623]

[0624] [Chemical Engineering 206]

[0625]

[0626] [Chemical 207]

[0627]

[0628] [Chemical Engineering 208]

[0629]

[0630] [Chemical Engineering 209]

[0631]

[0632] [Chemical 210]

[0633]

[0634] [Chemistry 211]

[0635]

[0636] [Chemistry 212]

[0637]

[0638] [Chemistry 213]

[0639]

[0640] [Chemistry 214]

[0641]

[0642] [Chemical 215]

[0643]

[0644] [Chemistry 216]

[0645]

[0646] [Chemistry 217]

[0647]

[0648] [Chemistry 218]

[0649]

[0650] [Chemistry 219]

[0651]

[0652] [Chem.220]

[0653]

[0654] [Chemistry 221]

[0655]

[0656] [Chemistry 222]

[0657]

[0658] [Chemistry 223]

[0659]

[0660] [Chemistry 224]

[0661]

[0662] [Chemistry 225]

[0663]

[0664] [Chemistry 226]

[0665]

[0666] [Chemistry 227]

[0667]

[0668] [Chemistry 228]

[0669]

[0670] [Chemistry 229]

[0671]

[0672] [Chemistry 230]

[0673]

[0674] [Chemistry 231]

[0675]

[0676] [Chemistry 232]

[0677]

[0678] The aforementioned base polymer preferably contains repeating units represented by formula (b1) (hereinafter also referred to as repeating unit b1) or repeating units represented by formula (b2) (hereinafter also referred to as repeating unit b2).

[0679] [Chemistry 233]

[0680]

[0681] 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 containing at least one of the following structures: hydroxyl group (other than phenolic hydroxyl), 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 It 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. 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. c2 can be 0, 1, 2, 3 or 4. However, 1 ≤ c1 + c2 ≤ 5.

[0682] Specific examples of repeating unit b1 can be listed below, but are not limited to these. Additionally, in the following formula, R... A Same as above.

[0683] [Chemistry 234]

[0684]

[0685] [Chemistry 235]

[0686]

[0687] [Chemistry 236]

[0688]

[0689] [Chemistry 237]

[0690]

[0691] [Chemistry 238]

[0692]

[0693] [Chemistry 239]

[0694]

[0695] [Chemistry 240]

[0696]

[0697] [Chemistry 241]

[0698]

[0699] [Chemistry 242]

[0700]

[0701] [Chemistry 243]

[0702]

[0703] [Chemistry 244]

[0704]

[0705] [Chemistry 245]

[0706]

[0707] [Chemistry 246]

[0708]

[0709] [Chemistry 247]

[0710]

[0711] [Chemistry 248]

[0712]

[0713] [Chemistry 249]

[0714]

[0715] Specific examples of repeated unit b2 can be listed below, but are not limited to these. Additionally, in the following formula, R... A Same as above.

[0716] [Chemistry 250]

[0717]

[0718] [Chemistry 251]

[0719]

[0720] [Chemistry 252]

[0721]

[0722] [Chemistry 253]

[0723]

[0724] [Chemistry 254]

[0725]

[0726] Regarding repeating units b1 or b2, in ArF lithography, those with lactone rings as polar groups are particularly preferred, while in KrF lithography, EB lithography, and EUV lithography, those with phenolic sites are preferable.

[0727] The aforementioned base polymer may further contain at least one of the following: repeating units represented by formula (c1) (hereinafter also referred to as repeating unit c1), repeating units represented by formula (c2) (hereinafter also referred to as repeating unit c2), repeating units represented by formula (c3) (hereinafter also referred to as repeating unit c3), repeating units represented by formula (c4) (hereinafter also referred to as repeating unit c4), and repeating units represented by formula (c5) (hereinafter also referred to as repeating unit c5).

[0728] [Chemistry 255]

[0729]

[0730] In equations (c1) to (c5), RA Each can be independently composed of 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 also 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, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond. 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 also 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 hydrocarbon group, phenylene group, or naphthylene group having 1 to 10 carbon atoms, and the aliphatic hydrocarbon group may also contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or an lactone ring. 6 It can be a single bond, ether bond, ester bond, sulfonate bond, amide 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 alkylene groups with 1 to 20 carbon atoms, which may also contain heteroatoms. Z 8 Each is independently a single bond, ****-Z 81 -C(=O)-O-、****-C(=O)-NH-Z 81 -or ****-OZ 81 -. Z 81 It can also contain alkylene groups 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 91It is an aliphatic alkylene group, phenylene, fluorinated phenylene, or phenylene substituted with trifluoromethyl, having 1 to 6 carbon atoms, and may also contain a carbonyl group, ester bond, ether bond, or hydroxyl group. * indicates an atomic bond with the carbon atom of the main chain. ** indicates a bond with Z. 1 The atomic bonds. *** indicates the relationship between Z and 6 Atomic bonds. **** represents the bond between Z and Z. 7 Atomic bonds.

[0731] Z 21 Z 51 and Z 91 The aliphatic alkyl sub-group can be any of the following: linear, branched, or cyclic. Specific examples include: methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-2,2-diyl, butane-1,1-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-2,3-diyl, butane-1,4-diyl, 1,1-dimethylethane-1,2-diyl, pentane-1,5-diyl, 2-methylbutane-1,2-diyl, hexane-1,6-diyl, etc.; cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, cyclohexanediyl, etc.; and groups obtained by combining them.

[0732] Z 71 and Z 81 The sub-hydrocarbon group represented may contain heteroatoms and can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples are listed below, but are not limited to these.

[0733] [Chemistry 256]

[0734]

[0735] In the formula, the dashed lines represent atomic bonds.

[0736] In equation (c1), R 31 and R 32Each of the above-mentioned hydrocarbon groups can be independently a hydrocarbon group with 1 to 20 carbon atoms, and may also contain heteroatoms. The aforementioned hydrocarbon groups can be saturated or unsaturated, and can be linear, 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, which are preferably aryl groups. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group may be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- in the aforementioned hydrocarbon group may also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may 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, sulfonolactone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0737] Also, R 31 and R 32 They can also bond to each other and form rings together with the sulfur atoms they are bonded to. Specific examples of the aforementioned rings can be shown in the following formulas, etc.

[0738] [Chemistry 257]

[0739]

[0740] In the formula, the dashed line represents Z. 4 Atomic bonds.

[0741] Specific examples of the cation in repeating unit c1 can be listed below, but are not limited to these. Additionally, in the following formula, R... A Same as above.

[0742] [Chemistry 258]

[0743]

[0744] [Chemistry 259]

[0745]

[0746] [Chemistry 260]

[0747]

[0748] [Chemistry 261]

[0749]

[0750] [Chemistry 262]

[0751]

[0752] [Chemistry 263]

[0753]

[0754] [Chemistry 264]

[0755]

[0756] [Chemistry 265]

[0757]

[0758] [Chemistry 266]

[0759]

[0760] [Chemistry 267]

[0761]

[0762] In equation (c1), M - These are non-nucleophilic relative ions. The aforementioned non-nucleophilic relative ions are preferably halide ions, sulfonate anions, imide anions, and methylated acid anions. Specific examples of the aforementioned halide ions include chloride ions and bromide ions. Specific examples of the aforementioned sulfonate anions include: trifluoromethanesulfonate ions, 1,1,1-trifluoroethanesulfonate ions, nonafluorobutanesulfonate ions, and other fluoroalkyl sulfonate ions; toluenesulfonate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, 1,2,3,4,5-pentafluorobenzenesulfonate ions, and other aryl sulfonate ions; methanesulfonate ions, butanesulfonate ions, and other alkyl sulfonate ions, etc. Specific examples of the aforementioned imide anions (imide ions) include: bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, bis(perfluorobutylsulfonyl)imide ion, etc. Specific examples of the aforementioned methylated anions (methylated ions) include: tris(trifluoromethylsulfonyl)methylated ion, tris(perfluoroethylsulfonyl)methylated ion, etc.

[0763] Other examples of the aforementioned non-nucleophilic relative ions can be listed as anions represented by any of the formulas (c1-1) to (c1-4).

[0764] [Chemistry 268]

[0765]

[0766] 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 can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed and illustrated later as R in formula (c1-1-1). fa1 The same example represents hydrocarbon groups.

[0767] The anion represented by formula (c1-1) should preferably be represented by the following formula (c1-1-1).

[0768] [Chemistry 269]

[0769]

[0770] In equation (c1-1-1), Q 1 and Q 2 Each of the following is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; to improve solvent solubility, at least one of these is preferably trifluoromethyl. m is 0, 1, 2, 3, or 4, with 1 being particularly preferred. 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, with oxygen atoms being more preferred. Considering the high resolution achieved in the formation of fine patterns, hydrocarbon groups with 6 to 30 carbon atoms are particularly preferred.

[0771] In equation (c1-1-1), R fa1 The hydrocarbon group represented by carbon number 1 to 35 can be saturated or unsaturated, and can be linear, 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.

[0772] 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. This can result in the presence of 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, acetamidemethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, 3-oxocyclohexyl, etc.

[0773] In equation (c1-1-1), 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, with ester bonds being even better.

[0774] Specific examples of anions represented by equation (c1-1) are shown below, but are not limited to these. Additionally, in the following equation, Q... 1 As mentioned above, Ac is an acetyl group.

[0775] [Chemistry 270]

[0776]

[0777] [Chemistry 271]

[0778]

[0779] [Chemistry 272]

[0780]

[0781] [Chemistry 273]

[0782]

[0783] [Chemistry 274]

[0784]

[0785] [Chemistry 275]

[0786]

[0787] [Chemistry 276]

[0788]

[0789] [Chemistry 277]

[0790]

[0791] [Chemistry 278]

[0792]

[0793] [Chemistry 279]

[0794]

[0795] In equation (c1-2), R fb1 and R fb2 Each hydrocarbon group consists independently of a fluorine atom or may contain heteroatoms and has 1 to 40 carbon atoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed and illustrated as R in formula (c1-1-1). fa1 The same example represents a hydrocarbon group. R fb1 and R fb2 It should preferably be a fluorine atom or a straight-chain fluorinated alkyl group having 1 to 4 carbon atoms. Also, 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, at which point R fb1 and R fb2 The groups formed by mutual bonding should preferably be fluorinated ethylidene or fluorinated propyleneide.

[0796] In equation (c1-3), R fc1 R fc2 and R fc3 Each hydrocarbon group consists independently of a fluorine atom or may contain heteroatoms and has 1 to 40 carbon atoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed and illustrated as R in formula (c1-1-1). fa1 The same example represents a hydrocarbon group. R fc1 R fc2 and R fc3 It should preferably be a fluorine atom or a straight-chain fluorinated alkyl group having 1 to 4 carbon atoms. Also, 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, at which point R fc1 and R fc2 The groups formed by mutual bonding should preferably be fluorinated ethylidene or fluorinated propyleneide.

[0797] In equation (c1-4), Rfd 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 linear, branched, or cyclic. Specific examples can be listed and illustrated as R in formula (c1-1-1). fa1 The same example represents hydrocarbon groups.

[0798] Specific examples of anions represented by formula (c1-4) are listed below, but are not limited to these.

[0799] [Chemistry 280]

[0800]

[0801] [Chemistry 281]

[0802]

[0803] The aforementioned examples of non-nucleophilic relative ions can be further illustrated by anions having aromatic rings substituted with iodine or bromine atoms. Specific examples of such anions can be represented by the following formula (c1-5).

[0804] [Chemistry 282]

[0805]

[0806] In equation (c1-5), x is an integer satisfying 1 ≤ x ≤ 3. y and z are integers satisfying 1 ≤ y ≤ 5, 0 ≤ z ≤ 3, and 1 ≤ y + z ≤ 5. y should preferably be an integer satisfying 1 ≤ y ≤ 3, preferably 2 or 3. z should preferably be an integer satisfying 0 ≤ z ≤ 2.

[0807] In equation (c1-5), X BI When x and / or y are 2 or more, they can be the same or different.

[0808] In equation (c1-5), L 11 It is a saturated hydrocarbon group with 1 to 6 carbon atoms, consisting of a single bond, ether bond, or ester bond, or may also contain ether or ester bonds. The aforementioned saturated hydrocarbon group can be linear, branched, or cyclic.

[0809] 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, and the linker may also contain oxygen, sulfur or nitrogen atoms.

[0810] In equation (c1-5), R feThe carbon group may be a hydroxyl, carboxyl, fluorine, chlorine, bromine, or amino group, or may contain a fluorine, chlorine, bromine, hydroxyl, amino, or ether bond, and may be a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon oxy group having 1 to 20 carbon atoms, a hydrocarbon carbonyl group having 2 to 20 carbon atoms, a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms, or a hydrocarbon sulfonyl oxy 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 can be 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 also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms. R feD It is an aliphatic hydrocarbon group with 1 to 16 carbon atoms, an aryl group with 6 to 12 carbon atoms, or an aralkyl group with 7 to 15 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group with 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group with 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl oxy group with 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. The aforementioned hydrocarbon group, hydrocarbon oxy group, hydrocarbon carbonyl group, hydrocarbon oxycarbonyl group, hydrocarbon carbonyl oxy group, and hydrocarbon sulfonyl oxy group can be straight-chain, branched, or cyclic. When x and / or z are 2 or more, each R fe They can be the same or different.

[0811] Among them, R fe It is advisable to use hydroxyl groups, -N(R) feC )-C(=O)-R feD -N(R) feC )-C(=O)-OR feD Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc.

[0812] In equation (c1-5), Rf 11 ~Rf 14 Each of these atoms can be independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of them must be a fluorine atom or a trifluoromethyl group. Also, Rf 11 With Rf 12 They can also combine to form carbonyl groups. Rf 13 and Rf 14 All of them are fluorine atoms, which is of excellent quality.

[0813] Specific examples of anions represented by equation (c1-5) are shown below, but are not limited to these. Additionally, in the following equation, X... BI Same as above.

[0814] [Chemistry 283]

[0815]

[0816] [Chemistry 284]

[0817]

[0818] [Chemistry 285]

[0819]

[0820] [Chemistry 286]

[0821]

[0822] [Chemistry 287]

[0823]

[0824] [Chemistry 288]

[0825]

[0826] [Chemistry 289]

[0827]

[0828] [Chemistry 290]

[0829]

[0830] [Chemistry 291]

[0831]

[0832] [Chemistry 292]

[0833]

[0834] [Chemistry 293]

[0835]

[0836] [Chemistry 294]

[0837]

[0838] [Chemistry 295]

[0839]

[0840] [Chemistry 296]

[0841]

[0842] [Chemistry 297]

[0843]

[0844] [Chemistry 298]

[0845]

[0846] [Chemistry 299]

[0847]

[0848] [Chemical 300]

[0849]

[0850] [Chemical Engineering 301]

[0851]

[0852] [Chemical 302]

[0853]

[0854] [Chemical 303]

[0855]

[0856] [Chemical 304]

[0857]

[0858] [Chemical 305]

[0859]

[0860] The aforementioned non-nucleophilic relative ions may also include the fluorobenzenesulfonate anion bonded to an aromatic group containing an iodine atom as described in Japanese Patent No. 6648726, the anion with a mechanism of decomposition due to acid as described in International Publication No. 2021 / 200056 or Japanese Patent Application Publication No. 2021-70692, the anion with a cyclic ether group as described in Japanese Patent Application Publication No. 2018-180525 or Japanese Patent Application Publication No. 2021-35935, and the anion described in Japanese Patent Application Publication No. 2018-92159.

[0861] The aforementioned non-nucleophilic relative ions can also be further described in Japanese Patent Application Publication Nos. 2006-276759, 2015-117200, 2016-65016 and 2019-202974 as bulky benzenesulfonic acid derivatives without fluorine atoms, or in Japanese Patent Application Publication No. 6645464 as benzenesulfonate anions and alkylsulfonate anions bonded to aromatic groups containing iodine atoms without fluorine atoms.

[0862] The aforementioned non-nucleophilic relative ions may also be the anions of disulfonic acid described in Japanese Patent Application Publication No. 2015-206932, the anions of sulfonic acid on one side and sulfonamide or sulfonylimide on the other side as described in International Publication No. 2020 / 158366, and the anions of sulfonic acid on one side and carboxylic acid on the other side as described in Japanese Patent Application Publication No. 2015-24989.

[0863] In equations (c2) and (c3), d1 and d2 are independently 0, 1, 2 or 3, and should preferably be 1.

[0864] 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.

[0865] In equations (c2), (c3) and (c4), L 1 The bonds can be single bonds, ether bonds, ester bonds, carbonyl bonds, sulfonate bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. From a synthetic point of view, ether bonds, ester bonds, and carbonyl bonds are preferred, with ester bonds and carbonyl bonds being even more desirable.

[0866] 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. Among them, Rf 1 and Rf 2 To increase the acid strength of the produced acid, it is preferable that all atoms be 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 them, Rf is used to improve solvent solubility. 3 and Rf 4 At least one of them should preferably be trifluoromethyl.

[0867] In equation (c3), Rf 5 and Rf 6 Each can be 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 cannot all be hydrogen atoms simultaneously. Among them, Rf is used to improve solvent solubility. 5 and Rf 6 At least one of them should preferably be trifluoromethyl.

[0868] 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 It is preferable to have a fluorine atom, trifluoromethyl, difluoromethyl, trifluoromethoxy, difluoromethoxy, trifluoromethylthio, or difluoromethylthio, with fluorine, trifluoromethyl, or trifluoromethoxy being more preferred. When f is 2, 3, or 4, each Rf 7 They can be the same or different.

[0869] 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 linear, branched, or cyclic. Specific examples can be listed and illustrated in the description of formula (1) as R. 1 Examples of hydrocarbon groups are similar, but not limited to these. Also, when e3 is 2, 3, or 4, each R... 33 They can be the same or different.

[0870] Furthermore, when e3 is 2, 3, or 4, multiple R... 33 They can also bond with each other and form rings together with the carbon atoms they are bonded to. Specific examples of rings formed in this case include: cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the -CH2- in the aforementioned rings can also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, they may 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.

[0871] Specific examples of the anion in repeating unit c2 can be listed below, but are not limited to these. Additionally, in the following formula, R... A As mentioned above, Me is a methyl group.

[0872] [Chemical 306]

[0873]

[0874] [Chemical 307]

[0875]

[0876] [Chemical 308]

[0877]

[0878] [Chemical 309]

[0879]

[0880] [Chemical 310]

[0881]

[0882] [Chemistry 311]

[0883]

[0884] [Chemistry 312]

[0885]

[0886] [Chemistry 313]

[0887]

[0888] [Chemical 314]

[0889]

[0890] Specific examples of the anion in repeating unit c3 can be listed below, but are not limited to these. Additionally, in the following formula, R... A Same as above.

[0891] [Chemical 315]

[0892]

[0893] [Chemistry 316]

[0894]

[0895] [Chemistry 317]

[0896]

[0897] [Chemistry 318]

[0898]

[0899] [Chemistry 319]

[0900]

[0901] [Chem.320]

[0902]

[0903] [Chemistry 321]

[0904]

[0905] [Chemistry 322]

[0906]

[0907] Specific examples of the anion in repeating unit c4 can be listed below, but are not limited to these. Additionally, in the following formula, R... A Same as above.

[0908] [Chemistry 323]

[0909]

[0910] [Chemistry 324]

[0911]

[0912] [Chemistry 325]

[0913]

[0914] [Chemistry 326]

[0915]

[0916] [Chemistry 327]

[0917]

[0918] [Chemistry 328]

[0919]

[0920] [Chemistry 329]

[0921]

[0922] [Chemistry 330]

[0923]

[0924] [Chemistry 331]

[0925]

[0926] [Chemistry 332]

[0927]

[0928] [Chemistry 333]

[0929]

[0930] [Chemistry 334]

[0931]

[0932] [Chemistry 335]

[0933]

[0934] Specific examples of the anion in repeating unit c5 can be listed below, but are not limited to these. Additionally, in the following formula, R... A Same as above.

[0935] [Chemistry 336]

[0936]

[0937] In equations (c2) to (c5), A + The aforementioned onion cations include: sulfonium cations, monium cations, ammonium cations, etc., and preferably sulfonium cations or monium cations. Specific examples of the aforementioned sulfonium cations include those represented by formula (Z-1), those described in paragraphs

[0102] to

[0125] of Japanese Patent Application Publication No. 2024-3744, those described in paragraphs

[0070] to

[0085] of Japanese Patent Application Publication No. 2023-169812, and those represented by formula (Z-3), but are not limited thereto. Specific examples of the aforementioned monium cations include: those represented by formula (Z-2), those described in paragraph

[0181] of Japanese Patent Application Publication No. 2024-259, but are not limited thereto. Specific examples of the aforementioned ammonium cations include the same examples as those shown below as ammonium cations represented by formula (am-1), but are not limited thereto.

[0938] The specific structures of repeating units c1 to c5 can be listed as any combination of the aforementioned anions and cations.

[0939] Among the repeating units c1 to c5, considering the control of acid diffusion, repeating units c2 to c5 are preferable; considering the acid strength of the generated acid, repeating units c2, c4, and c5 are even better; and considering the solvent solubility, repeating unit c2 is even better.

[0940] The aforementioned base polymer may also contain repeating units (hereinafter also referred to as repeating units d) with a structure in which hydroxyl groups are protected by acid-indestructible groups. As for repeating units d, there are no particular restrictions if they have a structure in which one or more hydroxyl groups are protected, and the protecting groups can decompose and generate hydroxyl groups due to the action of acid, and they are preferably represented by the following formula (d1).

[0941] [Chemistry 337]

[0942]

[0943] 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.

[0944] In equation (d1), R 42 The acid-unstable group indicated can be one that deprotects and forms a hydroxyl group due to the action of an acid. R 42 There are no particular restrictions on the structure, and it is preferable to have an acetal structure, a ketal structure, an alkoxy carbonyl group, or an alkoxy methyl group represented by the following formula (d2), with an alkoxy methyl group represented by the following formula (d2) being particularly preferred.

[0945] [Chemistry 338]

[0946]

[0947] In the formula, * represents an atomic bond. R 43 It consists of hydrocarbon groups with 1 to 15 carbon atoms.

[0948] R 42 Specific examples of the acid-unstable group represented by formula (d2), the alkoxymethyl group represented by formula (d2), and the repeating unit d can be given as examples similar to those exemplified in the description of the repeating unit d described in Japanese Patent Application Publication No. 2020-111564.

[0949] The aforementioned base polymer may also contain repeating units e derived from indene, benzofuran, benzothiophene, acenaphthene, crromone, coumarin, norcamphediene, or derivatives thereof. Specific examples of monomers providing repeating units e are listed below, but are not limited thereto.

[0950] [Chemistry 339]

[0951]

[0952] The aforementioned base polymer may also contain repeating units f derived from dihydroindene, vinylpyridine, or vinylcarbazole.

[0953] 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, and 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.

[0954] The weight average molecular weight (Mw) of the aforementioned polymer is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no concern about a decrease in resolution caused by the inability to ensure the difference in dissolution rate before and after exposure. In addition, in the present invention, Mw is a polystyrene conversion measurement value obtained by gel permeation chromatography (GPC) using THF or N,N-dimethylformamide (DMF) as a solvent.

[0955] Furthermore, regarding the molecular weight distribution (Mw / Mn) of the aforementioned polymer, as the pattern rule is miniaturized, the influence of Mw / Mn tends to become larger. Therefore, in order to obtain a resist composition that can be ideally used for fine pattern sizes, Mw / Mn is preferably a narrow distribution of 1.0 to 2.0. If it is within the above range, there are few low molecular weight and high molecular weight polymers, and there is no concern about observing foreign substances on the pattern or deterioration of the pattern shape after exposure.

[0956] When synthesizing the aforementioned polymer, for example, monomers providing the aforementioned repeating units can be added with a radical polymerization initiator in an organic solvent and heated to carry out polymerization.

[0957] 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-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of these initiators added relative to the total monomers used in polymerization should preferably be 0.01–25 mol%. The reaction temperature should preferably be 50–150 °C, preferably 60–100 °C. The reaction time should preferably be 2–24 hours, but considering production efficiency, 2–12 hours is preferred.

[0958] The aforementioned polymerization initiator can be added to the monomer solution to supply the reactor, or a different initiator solution can be prepared and supplied to the reactor separately. Since there is a possibility that free radicals generated from the initiator may lead to polymerization and the formation of ultra-high molecular weight polymers during standby time, from a quality control perspective, the monomer solution and initiator solution should preferably be prepared separately and added dropwise. Acid-labile groups can be used directly 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 and 2-mercaptoethanol can be used in combination. In this case, the amount of these chain transfer agents added relative to the total amount of monomers used to polymerize should preferably be 0.01–20 mol%.

[0959] In the case of monomers containing hydroxyl groups, the hydroxyl groups can be replaced with acetal groups such as ethoxy-ethoxy, which are easily deprotected by acids, during polymerization. After polymerization, deprotection can be carried out using weak acids and water. Alternatively, acetyl groups, formyl groups, trimethylacetyl groups, etc., can be used for replacement first, and alkaline hydrolysis can be carried out after polymerization.

[0960] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene can be copolymerized with other monomers in an organic solvent with the addition of a free radical polymerization initiator and heated. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene can be used, and after polymerization, the acetoxy groups can be deprotected by alkaline hydrolysis to obtain polyhydroxystyrene or hydroxyvinylnaphthalene.

[0961] The alkali used in alkaline hydrolysis can be ammonia, triethylamine, etc. Furthermore, the reaction temperature should preferably be -20 to 100℃, with 0 to 60℃ being more ideal. The reaction time should preferably be 0.2 to 100 hours, with 0.5 to 20 hours being more ideal.

[0962] In addition, the amount of each monomer in the aforementioned monomer solution can be appropriately set, for example, in a manner that makes it an ideal content ratio for the aforementioned repeating units.

[0963] Regarding the polymer obtained by the aforementioned 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 to obtain the powder can be used as the final product. Considering the viewpoints of work efficiency and quality stabilization, it is advisable to use the polymer solution obtained by dissolving the powder obtained by the purification step into a solvent as the final product.

[0964] Specific examples of solvents used at this time can be cited from paragraphs

[0144] to

[0145] of Japanese Patent Application Publication No. 2008-111103, including ketones such as 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; and propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, and propylene glycol dimethyl ether. Ethers such as diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, 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.

[0965] In the aforementioned polymer solution, the polymer concentration is preferably 0.01–30% by mass, and more preferably 0.1–20% by mass.

[0966] The aforementioned reaction solutions and polymer solutions should be filtered. Filtering removes foreign matter and gels that could cause defects, effectively stabilizing the quality.

[0967] The materials used in the aforementioned filters include: fluorocarbon, cellulose, nylon, polyester, and hydrocarbon-based materials. For filtration steps involving corrosion inhibitors, filters made of fluorocarbons such as Teflon (a registered trademark), polyethylene, polypropylene, or nylon are preferable. The pore size of the filter can be appropriately selected according to the target cleanliness level, preferably below 100 nm, and even better, below 20 nm. Furthermore, these filters can be used individually or in combination. The filtration method can involve passing the solution only once, but circulating the solution and performing multiple filtrations is preferable. The filtration steps can be performed during the polymer manufacturing process, in any order and number of times, preferably filtering the reaction solution after the polymerization reaction, the polymer solution, or both.

[0968] (B) A single base polymer may be used alone, or two or more polymers with different composition ratios, Mw and / or Mw / Mn may be used in combination. Furthermore, (B) in addition to the aforementioned polymers, the base polymer may also contain hydrides of ring-opening metathesis polymers, for which the polymers described in Japanese Patent Application Publication No. 2003-66612 may be used.

[0969] [(C) Organic solvent]

[0970] The chemically amplified resist composition of the present invention may also contain an organic solvent as component (C). There are no particular limitations on whether the organic solvent in (C) is capable of dissolving the aforementioned components and the components described below. Specific examples of such organic solvents include: ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; 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, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as GBL; and mixtures thereof.

[0971] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and their mixed solvents are particularly suitable for the solubility of the base polymer of component (B).

[0972] In the chemically amplified resist composition of the present invention, the content of (C) organic solvent relative to 80 parts by mass of (B) base polymer is preferably 200 to 5000 parts by mass, and more preferably 400 to 3500 parts by mass. (C) organic solvent may be used alone or in combination of two or more.

[0973] [(D) Quenching agent]

[0974] The chemically amplified resist composition of the present invention may also contain a quencher as component (D). Furthermore, in the present invention, the quencher refers to a material used to prevent the acid generated from the photoacid generator in the chemically amplified resist composition from diffusing towards the unexposed area and forming a desired pattern by capturing the acid.

[0975] (D) Quenching agents can be listed as onion salts represented by formula (2) or (3).

[0976] [Transformation 340]

[0977]

[0978] In equation (2), R q1 It is a hydrocarbon group with 1 to 40 carbon atoms, which may contain hydrogen atoms or heteroatoms, but excludes those in which the hydrogen atom at the α-position of the sulfonate group is replaced by 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.

[0979] R q1 The hydrocarbon groups representing carbon numbers from 1 to 40 can be specifically listed as follows: 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, etc., alkyl groups with carbon numbers from 1 to 40; 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 may be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and a portion of the -CH2- group in the aforementioned hydrocarbon groups may also be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, these groups may contain hydroxyl, fluorine, chlorine, bromine, iodine, cyano, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonyl lactone ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc.]

[0980] R q2 The hydrocarbon group represented can be specifically exemplified as R. q1 In addition to the specific examples of substituents, examples include: fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, or fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl.

[0981] Specific examples of the anions of onium salts represented by equation (2) are listed below, but are not limited thereto.

[0982] [Chemistry 341]

[0983]

[0984] [Chemistry 342]

[0985]

[0986] [Chemistry 343]

[0987]

[0988] [Chemistry 344]

[0989]

[0990] [Chemistry 345]

[0991]

[0992] Specific examples of the anions of onium salts represented by equation (3) are listed below, but are not limited thereto.

[0993] [Chemistry 346]

[0994]

[0995] [Chemistry 347]

[0996]

[0997] [Chemistry 348]

[0998]

[0999] [Chemistry 349]

[1000]

[1001] [Chemical 350]

[1002]

[1003] In equations (2) and (3), Mq + The cation is an onium cation. Examples of onium cations include: sulfonium cation, ferrophosphate cation, ammonium cation, etc. Specific examples of the aforementioned sulfonium cation and ferrophosphate cation can be listed and illustrated in the descriptions of formulas (c2) to (c5) as A. + The specific examples of sulfonium cations and monium cations represented are similar, but not limited to, those described above. Specific examples of the aforementioned ammonium cations can be exemplified by those represented by the following formula (am-1).

[1004] [Chemistry 351]

[1005]

[1006] In equation (am-1), R q11 ~R q14 Each can be independently a hydrocarbon group with 1 to 40 carbon atoms, which may also contain heteroatoms. Also, R q11 and R q12 They can also bond to each other and form rings together with the nitrogen atoms they are bonded to. Specific examples of the aforementioned hydrocarbon groups can be listed and illustrated in the description of formula (1) as R. 1 The same example represents hydrocarbon groups.

[1007] Specific examples of ammonium cations represented by formula (am-1) are listed below, but are not limited thereto.

[1008] [Chemistry 352]

[1009]

[1010] Specific examples of onium salts represented by formula (2) or (3) can be listed as any combination of the aforementioned anions and cations. Furthermore, these onium salts can be readily prepared using ion exchange reactions employing known organic chemical methods. For example, Japanese Patent Application Publication No. 2007-145797 can be consulted regarding ion exchange reactions.

[1011] 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. Here, "weak acid" means an acidity that cannot deprotect the acid-instable groups of the 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 onium salt-type photoacid generators that have a conjugate base of a strong acid, such as sulfonic acid with fluorinated α-position, as a relative anion. That is, when onium salts that produce strong acids, such as sulfonic acid with fluorinated α-position, are mixed with onium salts that produce weak acids, such as unfluorinated sulfonic acid or carboxylic acid, if the strong acid generated from the photoacid generator due to high-energy ray irradiation collides with the 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. During this process, strong acids are exchanged for weak acids with low catalytic activity, thus the acid appears to be deactivated and acid diffusion can be controlled.

[1012] Furthermore, (D) the quencher may also be an onium salt having a sulfonium cation and a benzene oxide anion site within the same molecule as described in Japanese Patent No. 6848776, or an onium salt having a sulfonium cation and a carboxylate anion site within the same molecule as described in Japanese Patent No. 6583136, Japanese Patent Application Publication No. 2020-200311, or an onium salt having a monazine cation and a carboxylate anion site within the same molecule as described in Japanese Patent No. 6274755.

[1013] Here, it is believed that when the photoacid generator that produces strong acids is an onium salt, as mentioned above, the strong acid generated by high-energy ray irradiation can be exchanged for a weak acid. On the other hand, the weak acid generated by high-energy ray irradiation is not easily exchanged with the unreacted onium salt that produces strong acids. This is because onium cations more readily form ion pairs with the anions of strong acids.

[1014] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (2) or (3) as a quencher in (D), its content relative to 80 parts by mass of the base polymer in (B) is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass. If the onium salt type quencher in component (D) is within the aforementioned range, the resolution is good and there is no significant reduction in sensitivity, which is ideal. The onium salt represented by formula (2) or (3) can be used alone or in combination of two or more.

[1015] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as a (D) quencher. Examples of nitrogen-containing compounds for the (D) component include: first-, second-, or third-order amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Publication No. 2008-111103, and particularly include: amine compounds having hydroxyl groups, ether bonds, ester bonds, lactone rings, cyano groups, or sulfonate bonds. Also, compounds formed by protecting first- or second-order amines with urethane groups, as described in Japanese Patent No. 3790649, may also be included.

[1016] Alternatively, sulfonate sulfonates with nitrogen-containing substituents can be used as nitrogen-containing compounds. Such compounds function as quenchers in the unexposed areas, but lose their quenching ability in the exposed areas due to neutralization with the acid they generate, thus functioning as so-called photodegrading bases. By using photodegrading bases, the contrast between the exposed and unexposed areas can be enhanced. For example, Japanese Patent Application Publication No. 2009-109595 and Japanese Patent Application Publication No. 2012-46501 can be referenced for photodegrading bases.

[1017] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as a (D) quencher, its content relative to 80 parts by mass of the (B) base polymer is preferably 0.001 to 12 parts by mass, and 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.

[1018] [(E) Other photoacid generating agents]

[1019] The chemically amplified resist composition of the present invention may also contain a photoacid generator (hereinafter also referred to as other photoacid generators) other than component (A) as component (E). There are no particular limitations on other photoacid generators if they are compounds that generate acid when irradiated by high-energy rays. Ideal other photoacid generators can be represented by the following formulas (4) or (5).

[1020] [Chemistry 353]

[1021]

[1022] In equation (4), R 101 ~R 105Each can be independently a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. Also, R 101 R 102 and R 103 Any two of them can also bond to each other and form a ring together with the sulfur atoms they are bonded to.

[1023] Specific examples of the cations of sulfonium salts represented by formula (4) and ferrous salts represented by formula (5) can be listed and illustrated in the descriptions of formulas (c2) to (c5) as A. + The specific examples of sulfonium cations and monazine cations represented are similar, but not limited to these.

[1024] In equations (4) and (5), Xa - It is the anion of a strong acid. Examples of the anions of the aforementioned strong acids can be represented by any of the formulas (c1-1) to (c1-5).

[1025] Furthermore, other photoacid generating agents of component (E) should also be represented by the following formula (6).

[1026] [Chemistry 354]

[1027]

[1028] In equation (6), R 201 and R 202 Each can be independently a hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. R 203 It can also contain a hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. Also, R 201 R 202 and R 203 Any two of them can also bond to each other and form a ring together with the sulfur atoms they are bonded to.

[1029] R 201 and R 202 The hydrocarbon groups representing 1 to 30 carbon atoms can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, etc., alkyl groups with 1 to 30 carbon atoms; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornel, oxanorbornel, tricyclic [5.2.1.0] 2,6[Cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms, such as decyl and adamantyl; aryl groups with 6 to 30 carbon atoms, such as phenyl, tolyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl, and anthracene; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups may be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- group in the aforementioned hydrocarbon groups may also be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, groups may contain hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulopentalide ring, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups.]

[1030] R 203 The alkylene groups representing carbon atoms from 1 to 30 can be saturated or unsaturated, and can be linear, 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. Alkyl groups with 1 to 30 carbon atoms, such as heptadecanyl-1,17-diyl; cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms, such as cyclopentanediyl, cyclohexanediyl, norcamphenediyl, and adamantanediyl; 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, and tert-butylnaphthylene. 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, or halogen atoms, and a portion of the -CH2- group in the aforementioned alkylene group can also be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. This can result in the presence of hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone, sulfonate ring, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups. The aforementioned heteroatoms should preferably be oxygen atoms.

[1031] In equation (6), L EIt is a hydrocarbon group with 1 to 20 carbon atoms, which can be a single bond, an ether bond, or may contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed and illustrated as R. 203 The same example represents the subhydrocarbon group.

[1032] 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 group. However, X a X b X c and X d At least one of them is a fluorine atom or a trifluoromethyl atom.

[1033] The photoacid generator represented by formula (6) should preferably be represented by the following formula (6').

[1034] [Chemistry 355]

[1035]

[1036] In equation (6'), L E 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. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed and illustrated as R in formula (c1-1-1). fa1 The same example represents hydrocarbon groups. p and q are independently 0, 1, 2, 3, 4 or 5, and r is 0, 1, 2, 3 or 4.

[1037] The photoacid generator represented by formula (6) can be exemplified by the same example as the photoacid generator represented by formula (2) shown in Japanese Patent Application Publication No. 2017-26980.

[1038] Among the aforementioned photoacid generators, those containing anions represented by formula (c1-1-1) or (c1-4) exhibit low acid diffusion and excellent solvent solubility, making them particularly desirable. Furthermore, those represented by formula (6') exhibit extremely low acid diffusion, making them particularly desirable.

[1039] When the chemically amplified resist composition of the present invention contains other photoacid generating agents (E), their content relative to 80 parts by weight of the base polymer (B) is preferably 0.1 to 40 parts by weight, and more preferably 0.5 to 20 parts by weight. If the amount of photoacid generating agent (E) added is within the aforementioned range, the resolution is good, and there is no concern about foreign matter forming in the resist film after development or during peeling, which is ideal. Other photoacid generating agents (E) can be used alone or in combination of two or more.

[1040] [(F) Surfactant]

[1041] The chemically amplified resist composition of the present invention may further contain a surfactant as component (F). The surfactant (F) is preferably a surfactant that is insoluble or sparingly soluble in water but soluble in alkaline developing solution, or a surfactant that is insoluble or sparingly 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.

[1042] Surfactants that are insoluble or poorly soluble in water and alkaline developing solutions, among those listed in the aforementioned announcement, are preferably FC-4430 (manufactured by 3M Corporation), SURFLON (registered trademark) S-381 (manufactured by AGC SEIMI CHEMICAL), OLFINE (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC SEIMI CHEMICAL), and oxane ring-opening polymers represented by the following formula (surf-1).

[1043] [Chemistry 356]

[1044]

[1045] Here, R, Rf, A, B, C, m, and n are irrelevant to the foregoing description and apply only to formula (surf-1). R is an aliphatic group with 2 to 5 carbon atoms, ranging from 2 to 4 valences. Examples of the aforementioned aliphatic groups, for those with 2 valences, include: ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentane, etc.; examples of those with 3 or 4 valences include the following.

[1046] [Chemistry 357]

[1047]

[1048] In the formula, the dashed lines represent atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and neopentyl tertrol, respectively.

[1049] Among them, 1,4-butylene, 2,2-dimethyl-1,3-propylene, etc. are preferred.

[1050] Rf is trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. m is an integer from 0 to 3, n is an integer from 1 to 4, the sum of n and m is the valence of R, and 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 constituent units in formula (surf-1) is not specified; they can be block-bonded or randomly bonded. For details on the manufacture of surfactants based on partially fluorinated oxyheterocyclic butane ring-opening polymer systems, please refer to the specification of US Patent No. 5,650,483, etc.

[1051] Surfactants that are insoluble or sparingly soluble in water but soluble in alkaline developing solutions are useful in ArF immersion lithography when no resist film is used. They reduce water penetration and leaching by aligning with the surface of the resist film. Therefore, they are useful for suppressing the leaching of water-soluble components from the resist film and reducing damage to the exposure equipment. Furthermore, they are useful as soluble foreign matter that is unlikely to cause defects during alkaline development after exposure or post-exposure baking (PEB). Such surfactants, which are insoluble or sparingly soluble in water but soluble in alkaline developing solutions, are polymeric surfactants, also known as hydrophobic resins, and are particularly desirable for their high water repellency and improved hydrophobic properties.

[1052] Specific examples of such polymeric surfactants include those containing at least one repeating unit selected from any of the following formulas (7A) to (7E).

[1053] [Chemistry 358]

[1054]

[1055] 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 groups. R s1 Each can be 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 hydrocarbon group with 1 to 5 carbon atoms. R s3 Each can be independently a hydrogen atom, a hydrocarbon group having 1 to 15 carbon atoms, a fluorinated hydrocarbon group, or an acid-labile group. R s3 When the group is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group can also 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. R s5Each can be 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 a fluorinated hydrocarbon group with 1 to 15 carbon atoms, and it may also insert an ether bond or a carbonyl group between carbon bonds.

[1056] R s1 The hydrocarbon group representing 1 to 10 carbon atoms should preferably be a saturated hydrocarbon group, and can be linear, 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.

[1057] R s2 The alkylene group represented should preferably be a saturated alkylene group, and can be linear, branched, or cyclic. Specific examples include: methylene, ethylene, propylene, butylene, and pentylene.

[1058] R s3 or R s6 The hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include: saturated hydrocarbon groups; aliphatic unsaturated hydrocarbon groups such as alkenyl and alkynyl groups, which are preferably saturated hydrocarbon groups. The aforementioned saturated hydrocarbon groups can be exemplified as R... s1 In addition to those representing hydrocarbon groups, other examples include: undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, etc. R s3 or R s6 The fluorinated hydrocarbon groups can be categorized as groups in which some or all of the hydrogen atoms of the carbon atoms bonded to the aforementioned hydrocarbon groups are replaced by fluorine atoms. As mentioned above, ether bonds or carbonyl groups may also be inserted between their carbon-carbon bonds.

[1059] R s3 Specific examples of acid-instable groups can be listed as follows: groups represented by the aforementioned formulas (AL-3) to (AL-5), trialkylsilyl groups with alkyl groups having 1 to 6 carbon atoms, and alkyl groups containing oxygen groups having 4 to 20 carbon atoms.

[1060] R s4 The (u+1) valence hydrocarbon group or fluorinated hydrocarbon group can be any of the following: straight chain, branched, or cyclic. Specific examples can be listed as groups obtained by further removing u hydrogen atoms from the aforementioned hydrocarbon group or fluorinated hydrocarbon group.

[1061] R saThe fluorinated hydrocarbon group represented should preferably be saturated and can be linear, branched, or cyclic. Specific examples include those in which some or all of the hydrogen atoms of the aforementioned hydrocarbon group are replaced by fluorine atoms, such as: trifluoromethyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoro-1-propyl, 3,3,3-trifluoro-2-propyl, 2,2,3,3-tetrafluoropropyl, 1,1,1,3,3,3-hexafluoroisopropyl, 2,2,3,3,4,4,4-heptafluorobutyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 2,2,3,3,4,4,5,5,6,6,7,7-dodecylfluoroheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, 2-(perfluorodecyl)ethyl, etc.

[1062] Specific examples of repeating units represented by any of equations (7A) to (7E) can be listed below, but are not limited thereto. Additionally, in the following equation, R... B Same as above.

[1063] [Chemistry 359]

[1064]

[1065] [Hua360]

[1066]

[1067] [Chemistry 361]

[1068]

[1069] [Chemistry 362]

[1070]

[1071] [Chem.363]

[1072]

[1073] [Chem.364]

[1074]

[1075] The aforementioned polymeric surfactants may also contain repeating units other than those represented by formulas (7A) to (7E). Examples of other repeating units include repeating units derived from methacrylic acid, α-trifluoromethacrylic acid derivatives, etc. In polymeric surfactants, the content of 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.

[1076] The Mw of the aforementioned polymeric surfactant is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. The Mw / Mn ratio is preferably 1.0 to 2.0, and more preferably 1.0 to 1.6.

[1077] Methods for synthesizing the aforementioned polymeric surfactants include: providing repeating units represented by formulas (7A) to (7E), and monomers containing unsaturated bonds as needed, in an organic solvent, adding a free radical initiator, and heating to polymerize them. Examples of organic solvents used in polymerization include: toluene, benzene, THF, diethyl ether, dioxane, etc. Examples of polymerization initiators include: AIBN, 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl 2,2-azobis(2-methylpropionic acid), benzoyl peroxide, lauroyl peroxide, etc. The reaction temperature should preferably be 50–100°C. The reaction time should preferably be 4–24 hours. Acid-labile groups can be directly introduced into the monomer, or they can be protected or partially protected after polymerization.

[1078] When 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 relative to the total molar number of monomers used to polymerize them should preferably be 0.01–10 mol%.

[1079] When the chemically amplified resist composition of the present invention contains surfactant (F), its content relative to 80 parts by weight of the base polymer (B) is preferably 0.1 to 50 parts by weight, and more preferably 0.5 to 10 parts by weight. If the content of surfactant (F) is 0.1 parts by weight or more, it will sufficiently improve the receding contact angle between the resist film surface and water; if it is 50 parts by weight or less, the dissolution rate of the resist film surface to the developer is low, and the height of the formed fine pattern is sufficiently maintained. Surfactant (F) can be used alone or in combination of two or more.

[1080] [(G) Other ingredients]

[1081] The chemically amplified resist composition of the present invention may also contain compounds that decompose due to acid and produce acid (acid-increasing compounds), organic acid derivatives, fluorinated alcohols, and compounds with a Mw of 3000 or less whose solubility in the developer changes due to acid (dissolution inhibitors) as other components (G). The aforementioned acid-increasing compounds can be referred to in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608. When containing the aforementioned acid-increasing compounds, their content relative to 80 parts by mass of the base polymer (B) is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass. Excessive content may sometimes make acid diffusion control difficult, leading to degradation of resolution and pattern shape. The aforementioned organic acid derivatives, fluorinated alcohols, and dissolution inhibitors can be referred to in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608.

[1082] [Pattern Formation Method]

[1083] The pattern forming method of the present invention includes the following steps:

[1084] A resist film is formed on the substrate using the aforementioned chemically amplified resist composition.

[1085] The aforementioned resist film was exposed to high-energy rays, and

[1086] The previously exposed resist film was developed using a developer.

[1087] The aforementioned substrates may be, for example, substrates used in integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) or substrates used in mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.).

[1088] The resist film can be formed, for example, by using spin coating or other methods to coat the aforementioned chemically amplified resist composition onto a substrate with a film thickness preferably of 0.05 to 2 μm, and then pre-baking it on a hot plate at a temperature preferably of 60 to 150°C for 1 to 10 minutes, more preferably at 80 to 140°C for 1 to 5 minutes.

[1089] High-energy rays used for photoresist film exposure include: KrF excimer laser, ArF excimer laser, EB, and EUV with wavelengths of 3–15 nm. When using KrF excimer laser, ArF excimer laser, or EUV for exposure, a mask for forming the desired pattern can be used, and the exposure dose should preferably be 1–200 mJ / cm². 2 And preferably, it should be 10–100 mJ / cm 2The process is carried out by irradiation. When using EB, a mask is used to form the desired pattern, or the exposure dose should be 1–300 μC / cm. 2 And preferably, it should be 10–200 μC / cm 2 Irradiation is performed in this manner.

[1090] In addition to the conventional exposure method, exposure can also be performed using an immersion method, in which a liquid with a refractive index of 1.0 or higher is inserted between the resist film and the projection lens. In this case, a water-insoluble protective film can also be used.

[1091] The aforementioned water-insoluble protective film is used to prevent leaching from the resist film and to improve the hydrophobicity of the film surface. It is broadly classified into two types. One type is an organic solvent-stripping type, which must be stripped using 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 preferred because it is 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, and is dissolved in alcohol solvents with 4 or more carbon atoms, ether solvents with 8 to 12 carbon atoms, or mixtures thereof. It is also possible to produce a material by dissolving the aforementioned water-insoluble but alkaline developing solution-soluble surfactant in alcohol solvents with 4 or more carbon atoms, ether solvents with 8 to 12 carbon atoms, or mixtures thereof.

[1092] PEB can also be performed after exposure. 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 80–140°C for 1–3 minutes.

[1093] For example, a developing solution containing 0.1 to 5% by mass, preferably 2 to 3% by mass, such as tetramethylammonium hydroxide (TMAH), can be used. Common methods such as dip, immersion, and spray can be employed for 0.1 to 3 minutes, preferably 0.5 to 2 minutes. This allows the exposed areas to dissolve and form the desired pattern on the substrate.

[1094] Furthermore, after the resist film is formed, it can be rinsed with pure water to extract acid-generating agents or wash away particulate matter from the film surface. It can also be rinsed to remove water remaining on the film after exposure.

[1095] In addition, a double patterning method can also be used to form patterns. Examples of double patterning methods include: a trench method that uses a first exposure and etching to process a 1:3 trench pattern substrate, then offsets the position and uses a second exposure to form a 1:3 trench pattern, thus forming a 1:1 pattern; and a line method that uses a first exposure and etching to process a 1:3 isolated residual pattern on a first substrate, then offsets the position and uses a second exposure under the first substrate to form a 1:3 isolated residual pattern, and then processes this second substrate to form a 1:1 pattern with a pitch of half.

[1096] In the pattern forming method of the present invention, a negative tone development method can also be used, in which the aforementioned alkaline aqueous solution is replaced with an organic solvent as the developer to dissolve the unexposed portion.

[1097] In the aforementioned 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, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, methyl valerate, methyl valerate, methyl crotonate. Ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, 2-phenylethyl acetate, etc. These organic solvents can be used alone or in combination of two or more.

[1098] Example

[1099] The present invention will be specifically described below with examples of synthesis, embodiments, and comparative examples, but the present invention is not limited to the following embodiments. Furthermore, the apparatus used is described below.

[1100] MALDI TOF-MS: S3000 manufactured by Nippon Electronics Co., Ltd.

[1101] [1] Synthesis of onium salts

[1102] [Example 1-1] Synthesis of onium salt PAG-1

[1103] [Chem365]

[1104]

[1105] (1) Synthesis of intermediate In-1

[1106] Under a nitrogen atmosphere, sodium hydride (55% by mass, 1.4 g) was suspended in THF (100 g) in a reaction vessel. The internal temperature was raised to 50 °C, and a solution composed of starting material SM-2 (4.0 g) and THF (10 g) was added dropwise. After the dropwise addition, heating under reflux was carried out for 5 hours. Thereafter, the reaction solution was cooled to an internal temperature of 40 °C, and starting material SM-1 (20.6 g) was added little by little successively. After the addition, the internal temperature was raised to 50 °C and aged for 12 hours. After aging, water was added to stop the reaction, and dichloromethane (100 g) was added to extract the target substance. Thereafter, a usual aqueous work-up was carried out. After distilling off the solvent, diisopropyl ether was added to wash the residue, whereby 21.5 g of intermediate In-1 was obtained in the form of an oil (yield 87%).

[1107] (2) Synthesis of PAG-1

[1108] Under a nitrogen atmosphere, intermediate In-1 (21.5 g), starting material SM-3 (14.3 g), dichloromethane (80 g), and water (40 g) were added. After stirring for 15 minutes, the organic layer was separated and washed with water, and then concentrated under reduced pressure. Methyl isobutyl ketone (100 g) was added to the concentrated solution for azeotropic dehydration, and then diisopropyl ether was added for crystallization, whereby 30.3 g of the target substance PAG-1 was obtained in the form of white crystals (yield 92%).

[1109] MALDI TOF-MS: POSITIVE M + [[ID=eleven]]461 (corresponding to C 18 H 10 F4IS + )

[1110] NEGATIVE M - 800 (corresponding to C 14 H 13 I4O5S - )

[1111] [Examples 1-2 to 1-9] Synthesis of onium salts PAG-2 to PAG-9

[1112] Using the corresponding starting materials and known organic synthesis reactions, onium salts PAG-2 to PAG-9 represented by the following formula were synthesized.

[1113] [Chemical formula 366]

[1114]

[1115] [Chemical formula 367]

[1116]

[1117] [2] Synthesis of basic polymers

[1118] [Synthetic Example] Synthesis of basic polymers (P-1 to P-5)

[1119] 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, separated, 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 utilized... 1 The results were confirmed by H-NMR, and Mw and Mw / Mn were confirmed using GPC (solvent: THF, standard: polystyrene).

[1120] [Chem.368]

[1121]

[1122] [Chemistry 369]

[1123]

[1124] [3] Preparation of chemically amplified resist composition

[1125] [Examples 2-1 to 2-30, Comparative Examples 1-1 to 1-20]

[1126] The photoacid generators (PAG-1 to PAG-9) composed of the onium salts of the present invention, the comparative photoacid generators (PAG-A to PAG-E), other photoacid generators (PAG-X, PAG-Y), the base polymers (P-1 to P-5), and the quenchers (Q-1 to Q-4) were dissolved in a solvent containing 0.01% by mass of surfactant A (OMNOVA) to prepare a solution. The solution was filtered through a 0.2 μm Teflon (registered trademark) type filter to obtain the chemically amplified resist compositions (R-1 to R-30 and CR-1 to CR-20).

[1127] [Table 1]

[1128]

[1129] [Table 2]

[1130]

[1131]

[1132] In Tables 1 and 2, the solvent, other photoacid generators PAG-X and PAG-Y, comparative photoacid generators PAG-A to PAG-E, quenchers Q-1 to Q-4, and surfactant A are described below.

[1133] Solvent: PGMEA (Propylene Glycol Monomethyl Ether Acetate)

[1134] DAA (diacetone alcohol)

[1135] Other photoacid generators: PAG-X, PAG-Y

[1136] [Transformation 370]

[1137]

[1138] • Comparison of photoacid generating agents: PAG-A to PAG-E

[1139] [Chemistry 371]

[1140]

[1141] Quenching agents: Q-1 to Q-4

[1142] [Chemistry 372]

[1143]

[1144] Surfactant A: 3-methyl-3-(2,2,2-trifluoroethoxymethyl)oxetane-tetrahydrofuran-2,2-dimethyl-1,3-propanediol copolymer (manufactured by OMNOVA).

[1145] [Chemistry 373]

[1146]

[1147] a : (b + b') : (c + c') = 1 : 4 ~ 7 : 0.01 ~ 1 (molar ratio)

[1148] Mw = 1500

[1149] [4] Evaluation of EUV lithography (1)

[1150] [Examples 3-1 to 3-30, Comparative Examples 2-1 to 2-20]

[1151] The chemically amplified resist compositions (R-1 to R-30, CR-1 to CR-20) shown in Tables 1 and 2 were spin-coated onto a Si substrate with a silicon-containing spin-coating hard mask SHB-A940 (43% by mass) manufactured by Shin-Etsu Chemical Industry Co., Ltd., forming a film thickness of 20 nm. The substrate was pre-baked at 100°C for 60 seconds using a hot plate to obtain a resist film with a thickness of 50 nm. The aforementioned resist film was then subjected to exposure using an ASML EUV scanning exposure machine NXE3400 (NA 0.33, σ 0.9 / 0.6, dipole illumination), with variations in exposure amount and focus (exposure interval: 1 mJ / cm).2 An LS pattern with a size of 18 nm and a pitch of 36 nm was exposed on the wafer (focal spacing: 0.020 μm). After exposure, PEB was performed at the temperatures shown in Tables 3 and 4 for 60 seconds. Subsequently, immersion development was performed for 30 seconds with a 2.38% (w / w) TMAH aqueous solution, followed by rinsing with a surfactant-containing rinsing material and spin drying to obtain a positive pattern.

[1152] The LS pattern was observed using a Hitachi Advanced Technology Co., Ltd. (HIT) CG6300 measuring SEM, and the sensitivity, EL, LWR, depth of focus (DOF), and collapse limit were evaluated according to the following methods. The results are shown in Tables 3 and 4.

[1153] [Sensitivity Evaluation]

[1154] Calculate the optimal exposure Eop (mJ / cm) for obtaining an LS pattern with a linewidth of 18nm and a pitch of 36nm. 2 ), and let it be the sensitivity. The smaller the value, the higher the sensitivity.

[1155] [EL Review]

[1156] The EL (in %) is calculated using the following formula, based on the exposure within ±10% (16.2–19.8 nm) of the 18 nm spacing width in the aforementioned LS pattern. The larger this value, the better the performance.

[1157] EL(%)=(|E1-E2| / Eop)×100

[1158] E1: Provides optimal exposure for LS patterns with a linewidth of 16.2nm and a pitch of 36nm.

[1159] E2: Provides optimal exposure for LS patterns with a linewidth of 19.8nm and a pitch of 36nm.

[1160] Eop: Provides optimal exposure for LS patterns with a linewidth of 18nm and a pitch of 36nm.

[1161] [LWR Evaluation]

[1162] The dimensions at 10 points along the length of the line obtained by Eop irradiation of the LS pattern are measured, and the standard deviation (σ) of the result is calculated as 3 times the value (3σ) as the LWR. The smaller this value, the more uniform the line width and roughness of the pattern can be obtained.

[1163] [DOF Rating]

[1164] The focal depth is evaluated by determining the focal range formed within ±10% (16.2–19.8 nm) of the 18 nm dimension in the aforementioned LS pattern. The larger this value, the wider the focal depth.

[1165] [Collapse Limit Assessment of Line Patterns]

[1166] The line dimensions of the aforementioned LS pattern at various exposures were measured 10 times along its length for the optimal focal point. The finest line dimension that could be obtained without collapse was taken as the collapse limit dimension. The smaller this value, the better the collapse limit.

[1167] [Table 3]

[1168]

[1169]

[1170] [Table 4]

[1171]

[1172]

[1173] As shown in Tables 3 and 4, the chemically amplified resist composition containing the photoacid generator composed of the onium salt of the present invention exhibits good sensitivity and excellent EL, LWR, and DOF. Furthermore, it is confirmed that the collapse limit value is small, and the resistance to pattern collapse remains strong during the formation of fine patterns. Therefore, it is indicated that the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[1174] [5] Evaluation of EUV lithography (2)

[1175] [Examples 4-1 to 4-30, Comparative Examples 3-1 to 3-20]

[1176] The chemically amplified resist compositions (R-1 to R-30, CR-1 to CR-20) shown in Tables 1 and 2 were spin-coated onto a Si substrate with a silicon-containing spin-coating hard mask SHB-A940 (43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd., with a film thickness of 20 nm. The substrate was pre-baked at 105°C for 60 seconds using a hot plate to obtain a resist film with a thickness of 50 nm. The resist film was exposed using an ASML EUV scanning exposure machine NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, wafer-scale hole pattern with a pitch of 46 nm and a deviation of +20%). The resist film was then subjected to PEB for 60 seconds at the temperatures recorded in Tables 5 and 6 using a hot plate, followed by development with a 2.38% by mass TMAH aqueous solution for 30 seconds to form a hole pattern with a size of 23 nm.

[1177] Using a Hitachi Advanced Technologies (AG) CG6300 length measuring SEM, the exposure was measured when the hole size was formed at 23 nm, and this was set as the sensitivity. Furthermore, the size of 50 holes at this time was measured, and the standard deviation (σ) obtained from the results was set to three times the value (3σ) as the CDU. The results are shown in Tables 5 and 6.

[1178] [Table 5]

[1179]

[1180] [Table 6]

[1181]

[1182] The results shown in Tables 5 and 6 confirm that the chemically amplified resist composition containing the photoacid generator composed of the onium salt of the present invention has good sensitivity and excellent CDU.

Claims

1. A kind of 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 1 or 2; n4 is 0, 1 or 2; however, when n1 is 0, 2≤n2+n3+n4≤5, and when n1 is 1, 2≤n2+n3+n4≤7. L A It is an ether bond or an ester bond; R AL It is an acid-labile group; R 1 It can be a halogen atom other than fluorine and iodine atoms, a nitro group, 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, or a hydrocarbon thio group with 1 to 20 carbon atoms that may contain heteroatoms. When n4 is 2, there are 2 R groups. 1 They can be the same or different, and there are 2 Rs. 1 They can also bond to each other and form rings together with the carbon atoms they are bonded to; Z + It is a ium cation.

2. The onium salt according to claim 1, wherein, R AL It is an acid-instable group represented by the following formula (AL-1) or (AL-2); In the formula, R L1 R L2 and R L3 Each is independently a hydrocarbon group having 1 to 12 carbon atoms, and a portion of the -CH2- group may be substituted with -O- or -S-. When the hydrocarbon group contains an aromatic ring or multiple bonds, a portion or all of the hydrogen atoms in the aromatic ring or multiple bonds may be substituted with a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 4 carbon atoms that may also contain a halogen atom, or an alkoxy group having 1 to 4 carbon atoms that may also contain a halogen atom; furthermore, R L1 and R L2 They can also bond with each other to form a ring, and a portion of the -CH2- in this ring can be replaced by -O- or -S-; however, R L3 When R does not contain any of the following: alicyclic structure, aromatic ring, or multiple bonds, L1 and R L2 They bond together to form a ring, and a portion of the -CH2- in the ring can be replaced by -O- or -S-. R L4 and R L5 Each is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; R L6 It is a hydrocarbon group with 1 to 20 carbon atoms, and part of the -CH2- of this hydrocarbon group can also be replaced by -O- or -S-; also, R L5 and R L6 They can also bond to each other and to the carbon atoms and L atoms they are bonded to. B Together they form a heterocyclic group with 3 to 20 carbon atoms, and part of the -CH2- of the heterocyclic group can also be replaced by -O- or -S-; L B It can be -O- or -S-; * indicates an atomic bond with an adjacent oxygen atom.

3. The onium salt according to claim 1, wherein it is represented by the following formula (1A); In the formula, n2, n4, L A R AL R 1 and Z + Same as above.

4. The onium salt according to claim 1, wherein, Z + It is a sulfonium cation represented by formula (Z-1) or a monazine cation represented by formula (Z-2); In the formula, R ct1 ~R ct5 Each is an independent hydrocarbon group consisting of halogen atoms or may contain heteroatoms, having 1 to 30 carbon atoms; also, R ct1 and R ct2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to.

5. The onium salt according to claim 1, wherein, Z + The sulfonium cation is represented by the following formula (Z-3); In the formula, m1 is 0 or 1; m2 is 0 or 1; m3 is 0 or 1; m4 is 0, 1, 2, 3 or 4; m5 is 0, 1, 2, 3 or 4; m6 is 0, 1, 2, 3, 4, 5 or 6; m7 is 0, 1, 2, 3, 4, 5 or 6; m8 is 0, 1 or 2; m9 is 0, 1 or 2; m10 is 0, 1 or 2; m11 is 0 or 1; m12 is 0, 1, 2, 3 or 4; m13 is 0, 1 or 2; m14 is 0, 1 or 2. 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, 1 ≤ 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; and m4 + m12 ≥ 1. R F1 ~R F3 Each R is independently a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms with an oxygen atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; when m5 is 2 or more, each R F1 They can be the same or different. When m6 is 2 or more, each R... F2 They can be the same or different. When m7 is 2 or more, each R... F3 They can be the same or different; R ct6 ~R ct9 It can be a halogen atom other than iodine and fluorine atoms, a nitro group, a cyano 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 m8 is 2, there are 2 R groups. ct6 They can be the same or different, and there are 2 Rs. ct6 They can also 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, and there are 2 Rs. ct7 They can also bond to each other and form rings together with the carbon atoms they are bonded to. When m10 is 2, the two R atoms... ct8 They can be the same or different, and there are 2 Rs. ct8 They can also 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, and there are 2 Rs. ct9 They can also bond to each other and form rings together with the carbon atoms they are bonded to; Furthermore, S directly bonded to the sulfonium cation + The aromatic rings can also bond with each other and with S + Together they form a ring; 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; X L It is a single bond, or may contain a heteroatom and a hydrocarbon group with 1 to 40 carbon atoms.

6. The onium salt according to claim 5, wherein, The sulfonium cation represented by formula (Z-3) is represented by the following formula (Z-3-1); In the formula, m4~m10, m12~m14, R F1 ~R F3 R ct6 ~R ct9 L C L D and X L Same as above.

7. The onium salt according to claim 6, wherein, The sulfonium cation represented by formula (Z-3-1) is represented by the following formula (Z-3-2); In the formula, m4~m10, R F1 ~R F3 and R ct6 ~R ct8 Same as above.

8. A photoacid generator comprising an onium salt according to any one of claims 1 to 7.

9. A chemically amplified resist composition comprising the photoacid generator according to claim 8.

10. The chemically amplified resist composition according to claim 9 further comprises a base polymer containing repeating units represented by formula (a1) or (a2); In the formula, R A Each can be independently composed of a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; X 1 It is a single bond, phenylene, naphthylene, or *-C(=O)-OX 11 - and the phenylene or naphthylene group may also be replaced by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group with 1 to 10 carbon atoms containing a fluorine atom, or a saturated hydrocarbon group with 1 to 10 carbon atoms containing a fluorine atom, or a halogen atom; X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring; X 2 It is a single bond or *-C(=O)-O-; * indicates an atomic bond with a carbon atom in the main chain; R 11 It 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 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; 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 acid-labile group; a1 can be 0, 1, 2, 3 or 4.

11. The chemically amplified resist composition according to claim 10, wherein, The basic polymer contains repeating units represented by the following formula (a3); In the formula, b1 is 0 or 1; 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 consists of hydrogen atoms, fluorine atoms, methyl groups, or trifluoromethyl groups; X 3 For single bonds, *-C(=O)-O- or *-C(=O)-NH-; * indicates an atomic bond with a carbon atom in the main chain; X 4 It is a single bond, an aliphatic alkylene group, a carbonyl group, a sulfonyl group, or a combination thereof, having 1 to 4 carbon atoms; X 5 and X 6 Each can be independently an oxygen atom or a sulfur atom; however, X 4 and X 6 Bonded to adjacent carbon atoms in the aromatic ring; R 12 and R 13 Each of the following groups consists independently of a hydrogen atom, or may contain heteroatoms, and comprises a hydrocarbon group having 1 to 20 carbon atoms; furthermore, 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 can be a halogen atom, hydroxyl group, cyano group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; it can also be a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms; it can also be a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon thio group or -N(R) group with 1 to 20 carbon atoms containing heteroatoms. 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, and there are multiple Rs. 14 They can also bond to each other and form rings together with the carbon atoms of the aromatic rings they are bonded to.

12. The chemically amplified resist composition according to claim 10, wherein, The base polymer contains repeating units represented by formula (b1) or (b2); In the formula, R A Each can be independently composed of a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Y 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 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; it can also be a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms; it can also be a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; it can also be a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms; or it can be a hydrocarbon oxy 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; c2 can be 0, 1, 2, 3 or 4; however, 1≤c1+c2≤5.

13. The chemically amplified resist composition according to claim 10, wherein, The base polymer contains at least one of the repeating units represented by formula (c1), formula (c2), formula (c3), formula (c4), and formula (c5). In the formula, d1 and d2 are 0, 1, 2 or 3 independently, respectively; 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. R A Each can be independently composed of a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Z 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 an aliphatic alkylene group, phenylene group, or a divalent group obtained by combining them with 1 to 6 carbon atoms, and may also contain halogen atoms, carbonyl groups, ester bonds, ether bonds or hydroxyl groups; Z 3 It can be a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond; Z 4 It is a single bond, or an aliphatic alkylene group with 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may also contain halogen atoms, carbonyl groups, ester bonds, ether bonds, or hydroxyl groups; 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 alkylene group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the aliphatic alkylene group may also contain a halogen atom, hydroxyl group, ether bond, ester bond, or lactone ring; Z 6 It can be a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond; Z 7 Each is independently a single bond, ***-Z 71 -C(=O)-O-、***-C(=O)-NH-Z 71 -or ***-OZ 71 -;Z 71 It may also contain a hydrocarbon group with 1 to 20 carbon atoms; Z 8 Each is independently a single bond, ****-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; 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 also 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 and Z 6 atomic bonds; **** represents the bond between Z and Z. 7 atomic bonds; L 1 It can be a single bond, ether bond, ester bond, carbonyl group, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond; 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 It cannot simultaneously be a hydrogen atom; 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 alkoxy group having 1 to 6 carbon atoms; R 31 and R 32 Each can be independently a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms; also, 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 It can be a halogen atom other than fluorine, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms; when e3 is 2, 3 or 4, each R 33 Multiple Rs can be the same or different. 33 They can also bond to each other and form rings together with the carbon atoms they are bonded to; M - It is a non-nucleophilic relative ion; A + It is a ium cation.

14. The chemically amplified resist composition according to claim 9 further comprises an organic solvent.

15. The chemically amplified resist composition according to claim 9, further comprising a quenching agent.

16. The chemically amplified resist composition according to claim 7, further comprising a photoacid generator other than the photoacid generator according to claim 8.

17. The chemically amplified resist composition according to claim 9, further comprising a surfactant.

18. 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 9. The resist film was exposed to high-energy rays, and The exposed resist film was developed using a developer.

19. The pattern forming method according to claim 18, wherein, The high-energy rays are KrF excimer lasers, ArF excimer lasers, electron beams, or extreme ultraviolet rays with wavelengths of 3–15 nm.

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