Onium salt, chemically amplified resist composition, and pattern forming process

Abstract

The present invention addresses the use of onium salts in photolithography using high-energy rays. These onium salts exhibit excellent solvent solubility, high sensitivity, high contrast, and superior photolithography properties such as EL, LWR, CDU, MEF, EL, and DOF. The invention also provides chemical amplification inhibitor compositions containing the onium salt as photoacid generators, and a patterning method using the chemical amplification inhibitor composition. The solution of the present invention is an onium salt composed of an anion represented by formula (1A) and a cation represented by formula (1B).

Description

Technical Field

[0001] This invention relates to onium salts, chemical amplification inhibitor compositions, and patterns forming methods. Prior 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 have been regarded as promising next-generation microfabrication technologies.

[0003] ArF lithography, using ArF excimer laser light, was partially used starting with 130nm node devices and became the main lithography technology from the 90nm node onwards. As a next-generation lithography technology for the 45nm node, lithography using the 157nm F2 laser was initially considered promising, but development was delayed due to various problems. Therefore, 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, the aperture number (NA) of the projection lens could be designed to be 1.0 or higher, enabling the rapid development of high-resolution ArF immersion lithography systems (Non-Patent Document 1), which is now in the practical application stage. In this immersion lithography, a resist composition that is not easily dissolved in water is required.

[0004] In ArF lithography, to prevent the degradation of delicate and expensive optical materials, it is necessary to seek resist components with high sensitivity that can achieve sufficient resolution with low exposure. Regarding methods to achieve this, selecting components with high transparency at a wavelength of 193 nm is the most common approach. For example, regarding the base polymer, some have proposed polyacrylic acid and its derivatives, norbornene-maleic anhydride alternating polymers, polynorbornene, ring-opening metathesis polymers, and hydrides of ring-opening metathesis polymers, etc., which, considering the idea of ​​increasing the transparency of the resin monomers, can achieve some success.

[0005] In recent years, along with positive tone resists developed with alkaline aqueous solutions, negative tone resists developed with organic solvents have also attracted attention. To resolve extremely fine aperture patterns that cannot be achieved with positive tone using negative tone exposure, researchers have used high-resolution positive resist compositions and developed them with organic solvents to form negative patterns. 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, conventional positive ArF resist compositions can be used, and the pattern formation methods using these compositions are described in Patent Documents 1-3.

[0006] To adapt to the rapid miniaturization in recent years, the development of photoresist components has also progressed with the advancement of process technology. Various studies have been conducted on photoacid generators, generally using strontium salts composed of triphenylstrontium cations and perfluoroalkyl sulfonic acid anions. However, the generated acid, namely perfluoroalkyl sulfonic acids, especially perfluorooctanoic acid (PFOS), raises concerns about its poor biocompatibility, bioconcentration potential, and toxicity, making its application in photoresist components strictly controlled. Currently, photoacid generators that produce perfluorobutanesulfonic acid are used. However, if used in photoresist components, the resulting acid diffuses significantly, making it difficult to achieve high resolution. In response to this problem, various developments have been made regarding partially fluorinated alkyl sulfonic acids and their salts. For example, Patent Document 1, in accordance with prior art, describes a photoacid generator that produces α,α-difluoroalkyl sulfonic acid upon exposure. Specifically, it is a photoacid generator that produces bis(4-tert-butylphenyl)monazine-1,1-difluoro-2-(1-naphthyl)ethane sulfonate and α,α,β,β-tetrafluoroalkyl sulfonic acid. However, although their fluorine substitution rates are all reduced, the lack of decomposable substituents such as ester structures makes the environmental safety considerations regarding easy decomposition insufficient. Furthermore, there are limitations in the molecular design for varying the size of alkyl sulfonic acids, and the high cost of starting materials containing fluorine atoms.

[0007] Furthermore, with the shrinking of circuit linewidths, the contrast degradation caused by acid diffusion in resist compositions becomes more severe. This is because the pattern size is close to the diffusion length of the acid, leading to a larger dimensional deviation on the wafer (mask error factor (MEF)) relative to the mask dimensional deviation, resulting in reduced mask fidelity and deterioration of pattern rectangularity. Therefore, to fully realize the benefits of shorter wavelengths and higher NA of the light source, it is necessary to go beyond conventional methods of increasing material solubility contrast or suppressing acid diffusion. As one improvement method, lowering the baking temperature reduces acid diffusion, which improves MEF, but inevitably results in lower sensitivity.

[0008] Introducing high-bulky substituents and polar groups into photoacid generators is effective in inhibiting acid diffusion. Patent Document 4 describes a photoacid generator containing 2-acryloxy-1,1,3,3,3-pentafluoropropane-1-sulfonic acid, which exhibits excellent solubility and stability in solvents and allows for flexible molecular design. In particular, the photoacid generator containing 2-(1-adamantoxy)-1,1,3,3,3-pentafluoropropane-1-sulfonic acid, which incorporates high-bulky substituents, exhibits low acid diffusion. Furthermore, Patent Documents 5-7 describe photoacid generators formed by introducing condensed ring lactones, sulfonyl lactones, and thiolactones as polar groups. Although it has been confirmed that the acid diffusion inhibition effect caused by the introduction of polar groups results in a certain degree of performance improvement, the control of acid diffusion to a high degree is still insufficient. Considering MEF, pattern shape, sensitivity, etc., the lithography performance is still unsatisfactory.

[0009] Introducing polar groups into the anion of a photoacid generator is effective in inhibiting acid diffusion, but it is disadvantageous from the perspective of solvent solubility. In Patent Documents 8 and 9, experiments were conducted to improve solvent solubility by introducing alicyclic groups into the cationic portion of the photoacid generator to ensure solvent solubility; specifically, cyclohexane and adamantane rings were introduced. Although solubility is improved by introducing such alicyclic groups, a certain number of carbon atoms is required to ensure solubility. As a result, the molecular structure of the photoacid generator becomes larger, and the lithography properties such as linewidth roughness (LWR) and dimensional uniformity (CDU) deteriorate when forming fine patterns.

[0010] Furthermore, Patent Document 10 describes a photoacid generator that produces fluoroalkyl sulfonic acid with an aromatic condensation ring derived from anthracene in the anion. While this may confirm some improvement in lithography performance, the alkyl sulfonic acid structure lacks rigidity and has been restricted in recent years as an organofluorine compound targeted by PFAS. Therefore, concerns remain regarding its impact on the environment and human health.

[0011] Iodine atoms have very high absorption at a wavelength of 13.5 nm in EUV, thus confirming their ability to generate secondary electrons during exposure, which has attracted attention in EUV lithography. Patent Document 11 describes a photoacid generator formed by introducing iodine atoms into anions, and Patent Document 12 describes a photoacid generator containing polymeric groups formed by introducing iodine atoms into anions. Patent Document 13 describes a photoacid generator formed by introducing iodine atoms into both cations and anions. This confirms a certain degree of improvement in lithography performance, but the increased solubility of iodine atoms in organic solvents raises the risk of precipitation in the solvent.

[0012] Patent document 14 describes a photoacid generator in which multiple fluorine atoms are introduced into a cation. By introducing multiple fluorine atoms, the solvent solubility of the photoacid generator is improved, but it is still insufficient considering EUV absorption, and there is still room for improvement.

[0013] Patent documents 15-19 describe photoacid generators and quenchers (acid diffusion control agents) containing iodine and fluorine atoms in cations. Through these developments, improvements in the performance of these materials as resistive agents have been confirmed. However, the current viewpoint on acid diffusion control is still unsatisfactory, and there is a search for the development of resistive materials that are more useful in the formation of fine patterns. [Previous Technical Documents] [Patent Literature]

[0014] [Patent Document 1] Japanese Patent Application Publication No. 2008-281974 [Patent Document 2] Japanese Patent Application Publication No. 2008-281975 [Patent Document 3] Japanese Patent No. 4554665 [Patent Document 4] Japanese Patent Application Publication No. 2007-145797 [Patent Document 5] Japanese Patent No. 5061484 [Patent Document 6] Japanese Patent Application Publication No. 2016-147879 [Patent Document 7] Japanese Patent Application Publication No. 2015-63472 [Patent Document 8] Japanese Patent No. 5573098 [Patent Document 9] Japanese Patent No. 6461919 [Patent Document 10] Japanese Patent No. 7109178 [Patent Document 11] Japanese Patent No. 6720926 [Patent Document 12] Japanese Patent No. 6973274 [Patent Document 13] Japanese Patent No. 7041204 [Patent Document 14] Japanese Patent No. 7389562 [Patent Document 15] Japanese Patent Application Publication No. 2021-123579 [Patent Document 16] Japanese Patent Application Publication No. 2021-123580 [Patent Document 17] Japanese Patent Application Publication No. 2022-123839 [Patent Document 18] Japanese Patent Application Publication No. 2023-88869 [Patent Document 19] Japanese Patent Application Publication No. 2023-88870 [Non-patent literature]

[0015] [Non-patent literature 1] Journal of Photopolymer Science and Technology, Vol. 17, No. 4, p. 587-601 (2004) Summary of the Invention

[0016] [The problem that the invention aims to solve] In response to the high resolution requirements of resist patterns in recent years, resist systems using conventional onium salt-type photoacid generators cannot adequately suppress acid diffusion. As a result, there is a possibility of degradation in lithography performance such as contrast, LWR, CDU, MEF, exposure margin (EL), and depth of focus (DOF).

[0017] The present invention is made in view of the foregoing circumstances, and aims to provide an onium salt for use in chemical amplification resist compositions, particularly in photolithography using high-energy rays such as KrF excimer laser, ArF excimer laser, electron beam (EB), and EUV, which exhibits excellent solvent solubility, high sensitivity, high contrast, and excellent photolithography performance such as exposure margin (EL), LWR, CDU, MEF, EL, and DOF; a chemical amplification resist composition containing the onium salt as a photoacid generator; and a patterning method using the chemical amplification resist composition. [Methods for solving problems]

[0018] To achieve the aforementioned objectives, the inventors of this invention conducted repeated and dedicated research, and as a result, discovered that onium salts composed of aromatic sulfonic acid anions substituted with hydrocarbon groups containing at least one aromatic ring and triarylstrom cations containing iodine and fluorine atoms have excellent solvent solubility. Chemical amplification inhibitors used as photoacid generators exhibit high sensitivity and high contrast, are extremely effective in acid diffusion suppression systems, and have excellent photolithography properties such as LWR, CDU, MEF, EL, and DOF. They are also extremely effective in forming fine patterns, thus leading to the completion of this invention.

[0019] That is, the present invention provides the following onium salt, chemical amplification inhibitor composition and pattern formation method. 1. An onium salt, comprising an anion represented by formula (1A) and a cation represented by formula (1B). [Chemistry 1] In the formula, n1 is 0 or 1; n2 is an integer from 0 to 4; n3 is an integer from 0 to 4; but when n1 is 0, 0 ≤ n2 + n3 ≤ 4, and when n1 is 1, 0 ≤ n2 + n3 ≤ 6; n4 is 0 or 1; W is a hydrocarbon group containing at least one aromatic ring with 6 to 40 carbon atoms; this hydrocarbon group may also contain heteroatoms. RF1 is a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms; R1 can be a halogen atom other than fluorine, a nitro 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 n3 is 2, 3, or 4, each R1 can be the same or different, and multiple R1s can also bond to each other and form a ring together with the carbon atoms they are bonded to; LA1 and LB1 are each independently a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond; XL1 is a single bond, or may contain a heteroatom-containing alkyl group with 1 to 40 carbon atoms; [Chemistry 2] In the formula, m1 is 0 or 1; m2 is 0 or 1; m3 is 0 or 1; m4 is an integer from 0 to 4; m5 is an integer from 0 to 4; m6 is an integer from 0 to 6; m7 is an integer from 0 to 6; m8 is an integer from 0 to 2; m9 is an integer from 0 to 2; m10 is an integer from 0 to 2; m11 is 0 or 1; m12 is an integer from 0 to 4; m13 is an integer from 0 to 2; m14 is an integer from 0 to 2; but when m1 is 0, 0 ≤ m6 + m When m1 is 1, the system is 0≦m6+m9≦6; when m2 is 0, the system is 0≦m7+m10≦4; when m2 is 1, the system is 0≦m7+m10≦6; when m3 is 0, the system is 1≦m4+m5+m8+m14≦4; when m3 is 1, the system is 1≦m4+m5+m8+m14≦6; when m11 is 0, the system is 0≦m12+m13≦4; when m11 is 1, the system is 0≦m12+m13≦6; and m4+m12≧1; RF2 to RF4 are each independently a fluorine atom, a fluorinated saturated hydrocarbon group with 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group with 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group with 1 to 6 carbon atoms; when m5 is 2 or more, each RF2 can be the same or different from each other; when m6 is 2 or more, each RF3 can be the same or different from each other; when m7 is 2 or more, each RF4 can be the same or different from each other. R11~R14 can be halogen atoms other than iodine and fluorine atoms, nitro, cyano, or may contain hydrocarbon groups with 1~20 carbon atoms (heteroatomic), hydroxyl groups with 1~20 carbon atoms (heteroatomic), or thiol groups with 1~20 carbon atoms (heteroatomic); when m8 is 2, the two R11s can be the same or different, and the two R11s can also bond to each other and form a ring with the carbon atoms they are bonded to; when m9 is 2, the two R12s can be the same or different, and the two R12s can also bond to each other and form a ring with the carbon atoms they are bonded to; when m10 is 2, the two R13s can be the same or different, and the two R13s can also bond to each other and form a ring with the carbon atoms they are bonded to; when m13 is 2, the two R14s can be the same or different, and the two R14s can also bond to each other and form a ring with the carbon atoms they are bonded to. Furthermore, the aromatic rings of S+ directly bonded to the strontium cation can also bond with each other to form rings together with S+; LA2 and LB2 are each independently a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond; XL2 is a single bond, or may contain a heteroatom of 1 to 40 carbon atoms in an alkyl group. 2. As in 1, the onium salt, where W is represented by the following formula (W-1) or (W-2). [Chemistry 3] In the formula, n5 is 0 or 1; n6 is an integer from 0 to 4; n7 is an integer from 1 to 4; n8 is 0 or 1; n9 is 0 or 1; n10 is an integer from 0 to 4; n11 is an integer from 0 to 4; R2 can be a halogen atom other than hydrogen or iodine, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; R3 and R4 are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms; R5 to R9 are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group with 1 to 40 carbon atoms that may contain heteroatoms; The dashed lines represent atomic bonds with LA1. 3. Onium salts such as 1 or 2, wherein the anion is represented by the following formula (1A-1). [Chemistry 4] In the formula, n1~n4, W, RF1, R1 and LA1 are the same as those mentioned above. 4. An onium salt of any one of 1 to 3, wherein the cation is represented by the following formula (1B-1). [Chemistry 5] In the formula, m4~m10, m12~m14, RF2~RF4, R11~R14, LA2, LB2 and XL2 are the same as those mentioned above. 5. Onium salts as in 4, wherein the cation is represented by the following formula (1B-2). [Chemistry 6] In the formula, m4~m10, RF2~RF4 and R11~R13 are the same as those mentioned above. 6. A photoacid generator, comprising an onium salt of any one of 1 to 5. 7. A chemical amplification inhibitor composition comprising a photoacid generator such as 6. 8. The chemical amplification inhibitor composition of 7 further comprises a base polymer containing repeating units represented by formula (a1) or (a2). [Chemistry 7] In the formula, RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; X1 is a single bond, an phenyl group, a naphthyl group, or *-C(=O)-O-X11-. This phenyl or naphthyl group may also be substituted with 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 oxygen group with 1 to 10 carbon atoms containing a fluorine atom, or a halogen atom. X11 is a saturated hydrocarbon group with 1 to 10 carbon atoms, an phenyl group, or a naphthyl group. This saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. X2 represents a single bond or *-C(=O)-O-; * indicates an atomic bond with a carbon atom in the main chain; R21 can be a halogen atom, cyano, hydroxyl, nitro, or may contain a hydrocarbon group with 1 to 20 carbon atoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms, a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms, or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms. AL1 and AL2 are each independently acid-labile groups; a is an integer from 0 to 4. 9. A chemical amplification inhibitor composition as described in 8, wherein the base polymer comprises a repeating unit represented by the following formula (a3). [Chemistry 8] In the formula, b1 is 0 or 1; b2 is an integer from 0 to 3 when b1 is 0, and an integer from 0 to 5 when b1 is 1; RA can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; X3 represents a single bond, *-C(=O)-O-, or *-C(=O)-NH-; * indicates an atomic bond with a carbon atom in the main chain; X4 is a single bond, an aliphatic hydrocarbon group with 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining them; X5 and X6 are each independently oxygen or sulfur atoms; however, X4 and X6 are carbon atoms bonded to adjacent aromatic rings. R22 and R23 are each independently hydrogen atoms, or may contain heteroatoms and be hydrocarbon groups with 1 to 20 carbon atoms; furthermore, R22 and R23 may also bond to each other and form a ring together with the carbon atoms they are bonded to. R24 can be a halogen atom, hydroxyl group, cyano group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms containing heteroatoms, or -N(R24A)(R24B); R24A and R24B are each independently a hydrogen atom or a hydrocarbon group with 1 to 6 carbon atoms; when b2 is 2 or more, the multiple R24s can also bond to each other and form a ring together with the carbon atoms of the aromatic rings they are bonded to. 10. A chemical amplification inhibitor composition as in 8 or 9, wherein the base polymer comprises repeating units represented by formula (b1) or (b2). [Chemistry 9] In the formula, RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Y1 represents a single bond or *-C(=O)-O-; * indicates an atomic bond with a carbon atom in the main chain; R31 is a hydrogen atom, or a group with 1 to 20 carbon atoms containing at least one of the following: 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)-). R32 can be a halogen atom, hydroxyl group, carboxyl group, nitro group, cyano group, or may contain a hydrocarbon group with 1 to 20 carbon atoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms, a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms. b is an integer from 1 to 4; c is an integer from 0 to 4; but 1 ≦ b + c ≦ 5. 11. A chemical amplification inhibitor composition as described in any one of 8 to 10, wherein the base polymer comprises 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). [Chemistry 10] In the formula, d1 and d2 are each independently 0, 1, 2 or 3; e1 is 0 or 1; e2 is an integer from 0 to 4; e3 is an integer from 0 to 4; but when e1 is 0, 0 ≦ e2 + e3 ≦ 4, and when e1 is 1, 0 ≦ e2 + e3 ≦ 6; Each of RA can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Z1 is a single bond or may also have substituents; Z2 can be a single bond, **-C(=O)-O-Z21-, **-C(=O)-NH-Z21-, or **-O-Z21-; Z21 can be an aliphatic alkyl group with 1 to 6 carbon atoms, an alkyl phenyl group, or a divalent group obtained by combining them, and may also contain halogen atoms, carbonyl groups, ester bonds, ether bonds, or hydroxyl groups; Z3 can be a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond; Z4 is a single bond, or an aliphatic alkyl group with 1 to 6 carbon atoms, an alkylphenyl group, or a divalent group obtained by combining them; it may also contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z5 is a single bond, or may contain substituents such as phenyl, naphthyl, or *-C(=O)-O-Z51-; Z51 is an aliphatic alkyl group, phenyl, or naphthyl group with 1 to 10 carbon atoms, which may also contain halogen atoms, hydroxyl groups, ether bonds, ester bonds, or lactone rings; Z6 can be a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond; Z7 can be a single bond, ***-Z71-C(=O)-O-, ***-C(=O)-NH-Z71-, or ***-O-Z71-; Z71 can also be an alkyl group with 1 to 20 carbon atoms containing heteroatoms; Z8 can be a single bond, ****-Z81-C(=O)-O-, ****-C(=O)-NH-Z81-, or ****-O-Z81-; Z81 can also be a alkyl group with 1 to 20 carbon atoms and may contain heteroatoms. Z9 can be a single bond, methylene, ethyl, phenyl, fluorinated phenyl, trifluoromethyl-substituted phenyl, *-C(=O)-O-Z91-, *-C(=O)-N(H)-Z91-, or *-O-Z91-; Z91 can be an aliphatic phenyl group with 1 to 6 carbon atoms, phenyl, fluorinated phenyl, or trifluoromethyl-substituted phenyl, 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 Z1; *** indicates an atomic bond with Z6; **** indicates an atomic bond with Z7; L1 can be a single bond, ether bond, ester bond, carbonyl group, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond; Rf1 and Rf2 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Rf3 and Rf4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Rf5 and Rf6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; however, not all of Rf5 and Rf6 are simultaneously hydrogen atoms. Rf7 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 alkyl thio group having 1 to 6 carbon atoms; R41 and R42 are each independently hydrocarbon groups with 1 to 20 carbon atoms, and may also contain heteroatoms; furthermore, R41 and R42 can also bond with each other to form a ring together with the sulfur atoms they are bonded to. R43 can be a halogen atom other than fluorine, or it can be a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; when e3 is 2, 3 or 4, multiple R43 atoms can also bond with each other to form a ring with the carbon atoms they are bonded to; M- is a non-nucleophilic relative ion; A+ is an onium cation. 12. Any chemical amplification inhibitor composition as described in any of items 7 to 11 further contains an organic solvent. 13. Any chemical amplification inhibitor composition, such as that in any of 7 to 12, further includes a quencher. 14. The chemical amplification inhibitor composition of any one of 7 to 13 further includes a photoacid generating agent other than the photoacid generating agent of 6. 15. Any chemical amplification inhibitor composition as described in any of 7 to 14 further includes a surfactant. 16. A method for forming a pattern, comprising the following steps: A resist film is formed on the substrate using a chemically amplified resist composition such as any one of 7 to 15; The resist film was exposed to high-energy radiation. The exposed resist film was developed using a developer. 17. The pattern forming method of 16, wherein the high-energy ray is KrF excimer laser, ArF excimer laser, EB, or EUV with a wavelength of 3~15nm. [Effects of the Invention]

[0020] When patterning is performed using a chemical amplification resist composition containing the onium salt of the present invention as a photoacid generator, it exhibits high sensitivity and excellent acid diffusion suppression performance. The lithography properties of LWR, CDU, MEF, EL, DOF, etc., are improved, and the collapse of the resist pattern during the formation of fine patterns can be suppressed. Implementation

[0021] The present invention will now be described in detail. Furthermore, in the following description, depending on the structure represented by the chemical formula, there may be mirror-image isomers and non-mirror-image isomers due to the presence of asymmetric carbon. However, in this case, one chemical formula is used to represent these isomers. These isomers may be used individually or in mixtures of two or more.

[0022] [Salt] The onium salt system of the present invention includes anions represented by the following formula (1A). [Chemistry 11]

[0023] In equation (1A), n1 is 0 or 1. When n1 is 0, it is a benzene ring; when n1 is 1, it is a naphthalene ring. However, considering solvent solubility, a benzene ring with n1 of 0 is more ideal. n2 is an integer from 0 to 4. Considering raw material supply, when n1 is 1, n2 of 4 is more ideal. n3 is an integer from 0 to 4. However, when n1 is 0, 0 ≤ n2 + n3 ≤ 4; when n1 is 1, 0 ≤ n2 + n3 ≤ 6. n4 is 0 or 1. Considering acid diffusion control, n4 of 1 is more ideal.

[0024] In formula (1A), RF1 is a fluorine atom, a fluorinated saturated hydrocarbon group with 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group with 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group with 1 to 6 carbon atoms. For RF1, a fluorine atom, trifluoromethyl, difluoromethyl, trifluoromethoxy, difluoromethoxy, trifluoromethylthio, or difluoromethylthio is more ideal, while a fluorine atom, trifluoromethyl, or trifluoromethoxy is even more ideal. By using substituents containing or having fluorine atoms, the acid strength of the resulting acid is increased due to electron attraction, thus the deprotection reactions of unstable acid groups such as tertiary esters and tertiary ethers described later will proceed smoothly. When n2 is 2, 3, or 4, each RF1 can be the same or different.

[0025] In formula (1A), R1 can be a halogen atom other than fluorine, a nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms containing heteroatoms. Examples of halogen atoms other than fluorine include chlorine, bromine, and iodine atoms, with iodine being the most desirable. The hydrocarbon group 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, dibutyl, tributyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornel, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclounsaturated cycloalkyl 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. Among these, aryl is the most ideal. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, the -CH2- group in the aforementioned hydrocarbon group can also be replaced by a group containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, it may contain hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone, sulfonate, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups. When n3 is 2, 3, or 4, each R1 can be the same or different. Also, when n3 is 2, 3, or 4, the multiple R1s can bond to each other and form a ring together with the carbon atoms they bond to. Regarding the aforementioned rings, 5- to 8-membered rings are more ideal.

[0026] In formula (1A), W is a hydrocarbon group with 6 to 40 carbon atoms containing at least one aromatic ring, and the hydrocarbon group may also contain heteroatoms.

[0027] In equation (1A), for W, it is more ideal to use the basis expressed by the following equations (W-1) or (W-2). [Chemistry 12] In the formula, the dashed lines represent atomic bonds with LA1.

[0028] In formula (W-1), n5 is 0 or 1. When n5 is 0, it is a benzene ring; when n5 is 1, it is a naphthalene ring. However, considering solvent solubility, a benzene ring with n5 of 0 is more ideal. n6 is an integer from 0 to 4. When n5 is 0, n6 of 2, 3, or 4 is more ideal. Considering EUV light absorption, n6 of 3 or 4 is more ideal. n7 is an integer from 1 to 4. Considering raw material supply, n7 of 1 to 3 is more ideal. Considering acid diffusion control, n7 of 2 or 3 is more ideal.

[0029] In formula (W-1), R2 can be independently a halogen atom other than a hydrogen atom or an iodine atom, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms. Examples of halogen atoms other than iodine atoms include fluorine, chlorine, and bromine atoms, but fluorine atoms are preferred from the perspective of solvent solubility. Furthermore, specific examples of hydrocarbon groups with 1 to 20 carbon atoms that may contain heteroatoms include those similar to those exemplified in the description of R1 in formula (1A), but are not limited to these. For R2, a group with a branched or cyclic structure is preferred.

[0030] In formula (W-1), it is ideal for at least one of the R2 and iodine atoms to be bonded to a carbon atom adjacent to the carbon atom bonded to LA1. In this way, the rotation between the aromatic rings bonded to by them and the aromatic rings bonded to by the sulfonic acid group is suppressed around the -LA1-XL1-LB1- bond axis due to steric hindrance, which can reduce acid diffusion.

[0031] In formula (W-2), n8 is 0 or 1. When n8 is 0, it is a benzene ring; when n8 is 1, it is a naphthalene ring. Considering solvent solubility, a benzene ring with n8 of 0 is more ideal. n9 is 0 or 1. When n9 is 0, it is a benzene ring; when n9 is 1, it is a naphthalene ring. Considering solvent solubility, a benzene ring with n9 of 0 is more ideal. n10 is an integer from 0 to 4. Considering raw material supply, n10 being 0, 1, or 2 is more ideal. n11 is an integer from 0 to 4. Considering raw material supply, n11 being 0, 1, or 2 is more ideal.

[0032] In formula (W-2), R3 and R4 are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms. Regarding the aforementioned halogen atom, examples include fluorine, chlorine, bromine, and iodine atoms, with fluorine and iodine atoms being more ideal. Furthermore, regarding specific examples of hydrocarbon groups with 1 to 20 carbon atoms that may contain heteroatoms, examples can be those identical to those exemplified in the description of R1 in formula (1A), but are not limited to these. For R3 and R4, groups with branched or cyclic structures are more ideal.

[0033] In formula (W-2), R5 to R9 are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group with 1 to 40 carbon atoms that may contain heteroatoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine, but fluorine and iodine are preferred. Specific examples of hydrocarbon groups with 1 to 20 carbon atoms that may contain heteroatoms include those similar to those exemplified in the description of R1 in formula (1A), but are not limited to these. For R5 to R9, groups with branched or cyclic structures are preferred.

[0034] In formula (W-2), any two of R5 to R9 can bond with each other to form a ring together with the carbon atoms they bond to. As for the aforementioned rings, 5 to 8-membered rings are more ideal.

[0035] In formula (1A), LA1 and LB1 are each independently a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond. Among these, single bonds, ether bonds, or ester bonds are more ideal.

[0036] In formula (1A), XL1 is a single bond, or may contain a heteroatom and be a carbon group with 1 to 40 carbon atoms. The aforementioned heteroatom can be linear, branched, or cyclic; specific examples include alkyldiyl, cyclic saturated heteroatom, and heteroaryl. Specific examples of the aforementioned heteroatom include oxygen, nitrogen, and sulfur atoms.

[0037] Specific examples of XL1, which may contain heteroatoms and carbon atoms of 1 to 40, such as those shown below, are given, but are not limited to these. Furthermore, in the following formulas, * denotes the atomic bonds with LA1 and LB1, respectively. [Chemistry 13]

[0038] [Chemistry 14]

[0039] [Chemistry 15]

[0040] [Chemistry 16]

[0041] Among these, XL-0~XL-22 and XL-47~XL-58 are more ideal.

[0042] For anions represented by formula (1A), the one represented by formula (1A-1) is more ideal. [Chemistry 17] In the formula, n1~n4, W, RF1, R1 and LA1 are the same as those mentioned above.

[0043] Specific examples of anions represented by formula (1A) can be listed as shown below, but are not limited to these. Additionally, in the following formula, Me is a methyl group. [Chemistry 18]

[0044] [Chemistry 19]

[0045] [Chemistry 20]

[0046] [Chemistry 21]

[0047] [Chemistry 22]

[0048] [Chemistry 23]

[0049] [Chemistry 24]

[0050] [Chemistry 25]

[0051] [Chemistry 26]

[0052] [Chemistry 27]

[0053] [Chemistry 28]

[0054] [Chemistry 29]

[0055] [Chemistry 30]

[0056] [Chemistry 31]

[0057] [Chemistry 32]

[0058] [Chemistry 33]

[0059] [Chemistry 34]

[0060] [Chemistry 35]

[0061] [Chemistry 36]

[0062] [Chemistry 37]

[0063] [Chemistry 38]

[0064] [Chemistry 39]

[0065] [Chemistry 40]

[0066] [Chemistry 41]

[0067] [Chemistry 42]

[0068] [Chemistry 43]

[0069] [Chemistry 44]

[0070] [Chemistry 45]

[0071] [Chemistry 46]

[0072] [Chemistry 47]

[0073] [Chemistry 48]

[0074] [Chemistry 49]

[0075] [Transformation 50]

[0076] [Chemistry 51]

[0077] [Chemistry 52]

[0078] [Chemistry 53]

[0079] [Chemistry 54]

[0080] [Chemistry 55]

[0081] [Chemistry 56]

[0082] [Chemistry 57]

[0083] [Chem.58]

[0084] [Chemistry 59]

[0085] [Transformation 60]

[0086] [Chemistry 61]

[0087] [Chemistry 62]

[0088] [Chemistry 63]

[0089] [Chemistry 64]

[0090] [Chemistry 65]

[0091] [Chemistry 66]

[0092] [Chemistry 67]

[0093] [Chemistry 68]

[0094] [Chemistry 69]

[0095] [Chemistry 70]

[0096] [Chemistry 71]

[0097] [Chemistry 72]

[0098] [Chemistry 73]

[0099] [Chemistry 74]

[0100] [Chemistry 75]

[0101] [Chemistry 76]

[0102] [Chemistry 77]

[0103] [Chemistry 78]

[0104] [Chemistry 79]

[0105] [Chemistry 80]

[0106] [Chemistry 81]

[0107] [Chemistry 82]

[0108] [Chemistry 83]

[0109] [Chemistry 84]

[0110] [Chemistry 85]

[0111] [Chemistry 86]

[0112] [Chemistry 87]

[0113] [Chemistry 88]

[0114] [Chemistry 89]

[0115] [Chemistry 90]

[0116] [Chemistry 91]

[0117] [Chemistry 92]

[0118] [Chemistry 93]

[0119] [Chemistry 94]

[0120] [Chemistry 95]

[0121] [Chemistry 96]

[0122] [Chemistry 97]

[0123] [Chem. 98]

[0124] [Chemistry 99]

[0125] [Chemistry 100]

[0126] [Chemistry 101]

[0127] [Chemistry 102]

[0128] [Chemistry 103]

[0129] [Chemistry 104]

[0130] [Chemistry 105]

[0131] [Chemistry 106]

[0132] [Chemistry 107]

[0133] [Chemistry 108]

[0134] [Chemistry 109]

[0135] [Chemical 110]

[0136] [Chemistry 111]

[0137] [Chemistry 112]

[0138] [Chemistry 113]

[0139] [Chemistry 114]

[0140] [Chemistry 115]

[0141] [Chemistry 116]

[0142] [Chemistry 117]

[0143] [Chemistry 118]

[0144] [Chemistry 119]

[0145] [Chemistry 120]

[0146] [Chemistry 121]

[0147] [Chemistry 122]

[0148] [Chemistry 123]

[0149] [Chemistry 124]

[0150] [Chemistry 125]

[0151] [Chemistry 126]

[0152] [Chemistry 127]

[0153] [Chemistry 128]

[0154] [Chemistry 129]

[0155] [Chemistry 130]

[0156] [Chemistry 131]

[0157] [Chemistry 132]

[0158] [Chemistry 133]

[0159] [Chemistry 134]

[0160] [Chemistry 135]

[0161] [Chemistry 136]

[0162] [Chemistry 137]

[0163] [Chemistry 138]

[0164] [Chemistry 139]

[0165] [Chemistry 140]

[0166] [Chemistry 141]

[0167] [Chemistry 142]

[0168] [Chemistry 143]

[0169] [Chemistry 144]

[0170] [Chemistry 145]

[0171] [Chemistry 146]

[0172] [Chemistry 147]

[0173] [Chemistry 148]

[0174] [Chemistry 149]

[0175] [Chemistry 150]

[0176] [Chemistry 151]

[0177] [Chemistry 152]

[0178] [Chemistry 153]

[0179] [Chemistry 154]

[0180] [Chemistry 155]

[0181] [Chemistry 156]

[0182] [Chemistry 157]

[0183] [Chemistry 158]

[0184] [Chemistry 159]

[0185] [Chemistry 160]

[0186] [Chemistry 161]

[0187] [Chemistry 162]

[0188] [Chemistry 163]

[0189] [Chemistry 164]

[0190] [Chemistry 165]

[0191] [Chemistry 166]

[0192] [Chemistry 167]

[0193] [Chemistry 168]

[0194] [Chemistry 169]

[0195] [Chemistry 170]

[0196] [Chemistry 171]

[0197] [Chemistry 172]

[0198] [Chemistry 173]

[0199] [Chemistry 174]

[0200] [Chemistry 175]

[0201] [Chemistry 176]

[0202] [Chemistry 177]

[0203] [Chemistry 178]

[0204] [Chemistry 179]

[0205] [Chemistry 180]

[0206] [Chemistry 181]

[0207] [Chemistry 182]

[0208] [Chemistry 183]

[0209] [Chemistry 184]

[0210] [Chemistry 185]

[0211] [Chemistry 186]

[0212] [Chemistry 187]

[0213] [Chemistry 188]

[0214] [Chemistry 189]

[0215] [Chemistry 190]

[0216] [Chemistry 191]

[0217] [Chemistry 192]

[0218] [Chemistry 193]

[0219] [Chemistry 194]

[0220] [Chemistry 195]

[0221] [Chemistry 196]

[0222] [Chemistry 197]

[0223] [Chemistry 198]

[0224] [Chemistry 199]

[0225] [Chem.200]

[0226] [Chemical Engineering 201]

[0227] [Chemical Engineering 202]

[0228] [Chemical Engineering 203]

[0229] [Chemical 204]

[0230] [Chemical Engineering 205]

[0231] [Chemical Engineering 206]

[0232] [Chemical 207]

[0233] [Chemical Engineering 208]

[0234] [Chemical Engineering 209]

[0235] [Chemical 210]

[0236] [Chemistry 211]

[0237] [Chemistry 212]

[0238] [Chemistry 213]

[0239] [Chemistry 214]

[0240] [Chemical 215]

[0241] [Chemistry 216]

[0242] [Chemistry 217]

[0243] [Chemistry 218]

[0244] [Chemistry 219]

[0245] [Chem.220]

[0246] [Chemistry 221]

[0247] [Chemistry 222]

[0248] [Chemistry 223]

[0249] [Chemistry 224]

[0250] [Chemistry 225]

[0251] [Chemistry 226]

[0252] [Chemistry 227]

[0253] [Chemistry 228]

[0254] [Chemistry 229]

[0255] [Chemistry 230]

[0256] [Chemistry 231]

[0257] [Chemistry 232]

[0258] [Chemistry 233]

[0259] [Chemistry 234]

[0260] [Chemistry 235]

[0261] [Chemistry 236]

[0262] [Chemistry 237]

[0263] [Chemistry 238]

[0264] [Chemistry 239]

[0265] [Chemistry 240]

[0266] [Chemistry 241]

[0267] [Chemistry 242]

[0268] [Chemistry 243]

[0269] [Chemistry 244]

[0270] [Chemistry 245]

[0271] [Chemistry 246]

[0272] [Chemistry 247]

[0273] [Chemistry 248]

[0274] [Chemistry 249]

[0275] [Chemistry 250]

[0276] [Chemistry 251]

[0277] [Chemistry 252]

[0278] [Chemistry 253]

[0279] [Chemistry 254]

[0280] [Chemistry 255]

[0281] [Chemistry 256]

[0282] [Chemistry 257]

[0283] [Chemistry 258]

[0284] [Chemistry 259]

[0285] [Chemistry 260]

[0286] [Chemistry 261]

[0287] [Chemistry 262]

[0288] [Chemistry 263]

[0289] [Chemistry 264]

[0290] [Chemistry 265]

[0291] [Chemistry 266]

[0292] [Chemistry 267]

[0293] [Chemistry 268]

[0294] [Chemistry 269]

[0295] [Chemistry 270]

[0296] [Chemistry 271]

[0297] [Chemistry 272]

[0298] [Chemistry 273]

[0299] [Chemistry 274]

[0300] [Chemistry 275]

[0301] [Chemistry 276]

[0302] [Chemistry 277]

[0303] [Chemistry 278]

[0304] [Chemistry 279]

[0305] [Chemistry 280]

[0306] [Chemistry 281]

[0307] [Chemistry 282]

[0308] [Chemistry 283]

[0309] [Chemistry 284]

[0310] [Chemistry 285]

[0311] [Chemistry 286]

[0312] [Chemistry 287]

[0313] [Chemistry 288]

[0314] [Chemistry 289]

[0315] [Chemistry 290]

[0316] The onium salt of the present invention comprises a cation represented by the following formula (1B). [Chemistry 291]

[0317] In formula (1B), m1 is 0 or 1. When m1 is 0, it is a benzene ring; when m1 is 1, it is a naphthalene ring. However, considering solvent solubility, a benzene ring with m1 = 0 is more ideal. m2 is 0 or 1. When m2 is 0, it is a benzene ring; when m2 is 1, it is a naphthalene ring. However, considering solvent solubility, a benzene ring with m2 = 0 is more ideal. m3 is 0 or 1. When m3 is 0, it is a benzene ring; when m3 is 1, it is a naphthalene ring. However, considering solvent solubility, a benzene ring with m3 = 0 is more ideal.

[0318] In formula (1B), m4 is an integer from 0 to 4. The more iodine atoms in the cation structure, the higher the absorption of EUV, but the poorer the solvent solubility, which raises concerns about precipitation in the inhibitor composition. Therefore, m4 of 0, 1, 2 or 3 is more ideal, and 0, 1 or 2 is even more ideal.

[0319] In equation (1B), m5 is an integer from 0 to 4. Considering raw material supply, m5 being 0, 1, 2, or 3 is more ideal, with 0, 1, or 2 being even more ideal. m6 is an integer from 0 to 6. Considering raw material supply, m6 being 0, 1, 2, or 3 is more ideal, with 0, 1, or 2 being even more ideal. m7 is an integer from 0 to 6. Considering raw material supply, m7 being 0, 1, 2, or 3 is more ideal, with 0, 1, or 2 being even more ideal.

[0320] In equation (1B), m8 is an integer from 0 to 2. Considering the supply of raw materials, m8 being 0 or 1 is more ideal. m9 is an integer from 0 to 2. Considering the supply of raw materials, m9 being 0 or 1 is more ideal. m10 is an integer from 0 to 2. Considering the supply of raw materials, m10 being 0 or 1 is more ideal.

[0321] In formula (1B), m11 is 0 or 1. When m11 is 0, it is a benzene ring; when m11 is 1, it is a naphthalene ring. However, considering the solvent solubility, a benzene ring with m11 of 0 is more ideal.

[0322] In formula (1B), m12 is an integer from 0 to 4. The more iodine atoms in the cation structure, the higher the absorption of EUV, but the solvent solubility will become poor, and there is a concern about precipitation in the inhibitor composition. Therefore, m12 of 0, 1, 2 or 3 is more ideal, and 0, 1 or 2 is even more ideal.

[0323] In equation (1B), m13 is an integer from 0 to 2. From the perspective of raw material supply, it is more ideal for m13 to be 0 or 1. m14 is an integer from 0 to 2. From the perspective of synthesis, it is more ideal for m14 to be 0 or 1.

[0324] 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.

[0325] In formula (1B), RF2 to RF4 are each independently a fluorine atom, a fluorinated saturated hydrocarbon group with 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group with 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group with 1 to 6 carbon atoms. Among these, trifluoromethyl, trifluoromethoxy, and trifluorothiomethoxy are more ideal. When m5 is 2 or more, each RF2 can be the same or different from each other; when m6 is 2, each RF3 can be the same or different from each other; when m7 is 2, each RF4 can be the same or different from each other.

[0326] In formula (1B), R11 to R14 are halogen atoms other than iodine and fluorine atoms, nitro, cyano, or hydrocarbon groups with 1 to 20 carbon atoms containing heteroatoms, or hydrocarbon oxy groups with 1 to 20 carbon atoms containing heteroatoms, or hydrocarbon thio groups with 1 to 20 carbon atoms containing heteroatoms. The hydrocarbon groups, hydrocarbon oxy groups, and hydrocarbon thio groups mentioned above can be saturated or unsaturated, and can be linear, branched, or cyclic. For specific examples, those that are the same as those exemplified in the description of formula (1A) for the hydrocarbon group represented by R1 can be listed. Furthermore, some or all of the hydrogen atoms in the hydrocarbon group, hydrocarbon oxygen group, and hydrocarbon sulfur group mentioned above can be replaced by a group containing heteroatoms such as oxygen atom, sulfur atom, nitrogen atom, and halogen atom. The -CH2- part of the aforementioned hydrocarbon group can also be replaced by a group containing heteroatoms such as oxygen atom, sulfur atom, and nitrogen atom. As a result, it may contain hydroxyl group, cyano group, fluorine atom, chlorine atom, bromine atom, iodine atom, carbonyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulfonolactone ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl group, etc.

[0327] Furthermore, when m8 is 2, the two R11 atoms can be identical or different, and they can also bond together to form a ring with the carbon atoms they are bonded to. When m9 is 2, the two R12 atoms can be identical or different, and they can also bond together to form a ring with the carbon atoms they are bonded to. When m10 is 2, the two R13 atoms can be identical or different, and they can also bond together to form a ring with the carbon atoms they are bonded to. When m13 is 2, the two R14 atoms can be identical or different, and they can also bond together to form a ring with the carbon atoms they are bonded to. Specific examples of the rings formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norcamphene rings, and adamantane rings. Furthermore, some or all of the hydrogen atoms in the aforementioned ring can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. Similarly, some of the -CH2- groups in the aforementioned ring can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, the ring 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, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0328] Furthermore, the aromatic rings directly bonded to S+ in the strontium cation represented by formula (1B) can also bond to each other and form a ring together with S+. In this case, specific examples of the aforementioned ring structures can be represented by the following formulas. [Chemistry 292] In the formula, the dashed lines represent atomic bonds.

[0329] In formula (1B), LA2 and LB2 are each independently a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond. Among these, for LA2, a single bond, ether bond, ester bond, or sulfonate bond is more ideal, and an ester bond or sulfonate bond is even more ideal. For LB2, a single bond, ether bond, or ester bond is more ideal, and a single bond is even more ideal.

[0330] In formula (1B), XL2 is a single bond, or may contain a heteroatom and a carbon group with 1 to 40 carbon atoms. Examples of the aforementioned carbon groups with 1 to 40 carbon atoms that may also contain heteroatoms can be listed as those exemplified in the examples of carbon groups with 1 to 40 carbon atoms represented by XL1, but are not limited to these.

[0331] For strontium cations represented by formula (1B), the following formula (1B-1) is more ideal. [Chemistry 293] In the formula, m4~m10, m12~m14, RF2~RF4, R11~R14, LA2, LB2 and XL2 are the same as those mentioned above.

[0332] For cations represented by formula (1B-1), those represented by formula (1B-2) are more ideal. [Chemistry 294] In the formula, m4~m10, RF2~RF4 and R11~R13 are the same as those mentioned above.

[0333] Specific examples of strontium cations represented by formula (1B) are shown below, but are not limited to these. Additionally, in the following formula, Me is a methyl group. [Chemistry 295]

[0334] [Chemistry 296]

[0335] [Chemistry 297]

[0336] [Chemistry 298]

[0337] [Chemistry 299]

[0338] [Chemical 300]

[0339] [Chemical Engineering 301]

[0340] [Chemical 302]

[0341] [Chemical 303]

[0342] [Chemical 304]

[0343] [Chemical 305]

[0344] [Chemical 306]

[0345] [Chemical 307]

[0346] [Chemical 308]

[0347] [Chemical 309]

[0348] [Chemical 310]

[0349] [Chemistry 311]

[0350] [Chemistry 312]

[0351] [Chemistry 313]

[0352] [Chemical 314]

[0353] [Chemical 315]

[0354] [Chemistry 316]

[0355] [Chemistry 317]

[0356] [Chemistry 318]

[0357] [Chemistry 319]

[0358] [Chemistry 320]

[0359] [Chemistry 321]

[0360] [Chemistry 322]

[0361] In particular, any combination of anions and cations as described above can be cited as examples of the onium salts of the present invention.

[0362] Regarding the synthesis method of the onium salt of the present invention, methods described in Japanese Patent Application Publication No. 2010-155824 and Japanese Patent No. 7067271 can be cited, but the aforementioned manufacturing methods are only examples, and the manufacturing method of the onium salt of the present invention is not limited to these.

[0363] Regarding the structural features of the onium salt of the present invention, examples include: an aromatic sulfonic acid anion substituted with a hydrocarbon group containing at least one aromatic ring, and a triarylstrom cation containing iodine and fluorine atoms. The aforementioned triarylstrom cation containing iodine and fluorine atoms exhibits particularly high EUV absorption due to the iodine atom in 13.5 nm EUV lithography, resulting in the generation of secondary electrons from the iodine atom during exposure. Furthermore, the electron attraction effect of the fluorine atom lowers the energy level of the lowest unoccupied molecular orbital (LUMO) in Frontier orbital theory, making it more receptive to the generated secondary electrons. Therefore, the decomposition of the cation is promoted, leading to efficient acid production. On the other hand, the aforementioned hydrocarbon group containing at least one aromatic ring, excluding large substituents, functions as a large substituent, effectively suppressing the diffusion of the generated acid. In particular, this effect is easily obtained when the aforementioned hydrocarbon group containing at least one aromatic ring is a substituent aromatic ring structure as represented by formula (W-1) or a substituent condensed ring structure as represented by formula (W-2). Furthermore, because it is resistant to alkaline developing solutions, film loss in unexposed areas is reduced. On the other hand, the structure of the acid generated by the aromatic sulfonic acid structure is rigid, exhibiting an effect of inhibiting acid diffusion. In the aromatic ring forming the aromatic sulfonic acid structure, sulfonate bonds with fluorine atoms or electron-attracting linkages are ideal, thereby increasing the acidity of the generated acid and efficiently deprotecting the acid-unstable groups of the base polymer. Furthermore, although fluorine atoms are less abundant than iodine atoms, they are elements with high EUV light absorption; therefore, by increasing the number of fluorine atoms, the generation of secondary electrons increases, promoting cation decomposition and contributing to high sensitivity. While Japanese Patent No. 7109178 discloses alkylsulfonic acid-type photoacid generators with 2 to 4 fluorine atoms, these alkylsulfonic acids exhibit greater acid diffusion and poor solvent solubility, raising concerns about development defects. Through these synergistic effects, the onium salt inhibitor composition of this invention possesses high sensitivity and low acid diffusion, thereby enabling the formation of excellent line pattern LWR, hole pattern CDU, and patterns with strong resistance to pattern collapse, making it ideal for forming fine patterns.

[0364] The aforementioned onium salts are ideally suited for use as photoacid generators.

[0365] [Chemical Amplification Inhibitor Composition] [(A) Photoacid generator] The chemical amplification inhibitor composition of the present invention includes (A) a photoacid generator composed of onium salts represented by formulas (1A) and (1B) as an essential component.

[0366] In the chemical amplification inhibitor composition of the present invention, the content of the photoacid generator composed of onium salt in component (A) is ideally 0.1 to 40 parts by mass relative to 80 parts by mass of the base polymer described later, and more ideally 0.5 to 30 parts by mass. If the content of component (A) falls within the aforementioned range, the sensitivity and resolution are good, and there is no risk of foreign matter problems arising after development or peeling of the inhibitor film, which is therefore ideal. The photoacid generator (A) can be used alone or in combination of two or more.

[0367] [(B) Basic Polymer] The chemical amplification inhibitor composition of the present invention may also contain a base polymer as component (B). The base polymer (B) comprises 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.). [Chemistry 323]

[0368] In formulas (a1) and (a2), RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0369] In formula (a1), X1 is a single bond, an phenyl group, a naphthyl group, or *-C(=O)-O-X11-. This phenyl or naphthyl group may be substituted with a saturated hydrocarbon group containing 1 to 10 carbon atoms (including hydroxyl, nitro, cyano, or fluorine atoms), a saturated hydrocarbon oxygen group containing 1 to 10 carbon atoms, or a halogen atom. X11 is a saturated hydrocarbon group containing 1 to 10 carbon atoms, an phenyl group, or a naphthyl group. This saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. * indicates an atomic bond with a carbon atom in the main chain.

[0370] In formula (a2), X2 is a single bond or *-C(=O)-O-. * indicates an atomic bond with a carbon atom in the main chain. R21 is a halogen atom, cyano group, hydroxyl group, nitro group, or may contain a hydrocarbon group with 1-20 carbon atoms, a hydrocarbon oxygen group with 1-20 carbon atoms, a hydrocarbon carbonyl group with 2-20 carbon atoms, a hydrocarbon carbonyl oxygen group with 2-20 carbon atoms, or a hydrocarbon oxygen carbonyl group with 2-20 carbon atoms. a is an integer from 0 to 4, ideally 0 or 1.

[0371] In formulas (a1) and (a2), AL1 and AL2 are each independently acid-indestructible groups. Specific examples of the aforementioned acid-indestructible groups can be cited in Japanese Patent Application Publication Nos. 2013-80033 and 2013-83821.

[0372] In terms of representativeness, specific examples of the aforementioned unstable acid groups can be listed as those represented by formulas (AL-1) to (AL-3). [Chemistry 324] In the formula, the dashed lines represent atomic bonds.

[0373] In formulas (AL-1) and (AL-2), RL1 and RL2 are each independently a hydrocarbon group with 1 to 40 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. Among the aforementioned hydrocarbon groups, those with 1 to 20 carbon atoms are more ideal.

[0374] In equation (AL-1), a1 is an integer from 0 to 10, and it is more ideal to be an integer from 1 to 5.

[0375] In formula (AL-2), RL3 and RL4 are each independently a hydrogen atom or a hydrocarbon group with 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. Among the aforementioned hydrocarbon groups, those with 1 to 20 carbon atoms are preferred. Furthermore, any two of RL2, RL3, and RL4 can bond with each other to form a ring with 3 to 20 carbon atoms, together with the carbon atoms they bond to, or with carbon and oxygen atoms. Among the aforementioned rings, rings with 4 to 16 carbon atoms are preferred, especially alicyclic rings.

[0376] In formula (AL-3), RL5, RL6, and RL7 are each independently a hydrocarbon group with 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. Among the aforementioned hydrocarbon groups, those with 1 to 20 carbon atoms are preferred. Furthermore, any two of RL5, RL6, and RL7 can bond with each other to form a ring with 3 to 20 carbon atoms. Among the aforementioned rings, rings with 4 to 16 carbon atoms are preferred, especially alicyclic rings.

[0377] Specific examples of the repeating unit a1 can be listed as shown below, but are not limited to these. Furthermore, in the following formula, RA and AL1 are the same as those described above. [Chemistry 325]

[0378] [Chemistry 326]

[0379] [Chemistry 327]

[0380] [Chemistry 328]

[0381] Specific examples of the repeating unit a2 can be listed as shown below, but are not limited to these. Furthermore, in the following formula, RA and AL2 are the same as those described above. [Chemistry 329]

[0382] [Chemistry 330]

[0383] [Chemistry 331]

[0384] The aforementioned polymer may also contain repeating units represented by the following formula (a3) ​​(hereinafter also referred to as repeating unit a3). [Chemistry 332]

[0385] In formula (a3), b1 is 0 or 1. When b1 is 0, it represents a benzene ring; when b1 is 1, it represents a naphthalene ring. Considering solvent solubility, a benzene ring with b1 being 0 is more ideal. b2 is an integer from 0 to 3 when b1 is 0, and an integer from 0 to 5 when b1 is 1. Considering raw material supply, b2 being 0, 1, 2, or 3 is more ideal, with 0, 1, or 2 being even more ideal.

[0386] In formula (a3), RA can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, hydrogen atom and methyl group are more ideal, and hydrogen atom is even more ideal.

[0387] In formula (a3), X3 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond with a carbon atom in the main chain. Among these, a single bond or *-C(=O)-O- is more ideal, and a single bond is even more ideal.

[0388] In formula (a3), X4 is a single bond, an aliphatic hydrocarbon 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 more ideal; considering the polar group generated after the reaction, a single bond or a carbonyl group is more ideal.

[0389] In formula (a3), X5 and X6 are each independently an oxygen atom or a sulfur atom. However, X4 and X6 are carbon atoms bonded to adjacent aromatic rings. X5 and X6 can be the same or different; considering reactivity, it is more ideal for X5 and X6 to be both oxygen atoms.

[0390] In formula (a3), R22 and R23 are each independently hydrogen atoms, or may contain hydrocarbon groups with 1 to 20 carbon atoms containing 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, dibutyl, tributyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norcamphenyl, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclohexenyl groups with 3 to 20 carbon atoms; 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 a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. Similarly, the -CH2- part of the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may also 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.

[0391] Furthermore, R22 and R23 can also bond to each other and form rings together with the carbon atoms they bond to. Specific examples of rings formed in this way include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, and adamantane rings. Also, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, the -CH2- group in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the rings 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)-), and haloalkyl groups.

[0392] In formula (a3), R24 can be a halogen atom, hydroxyl group, cyano group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxycarbonyl group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms containing heteroatoms, or -N(R24A)(R24B). R24A and R24B are each independently a hydrogen atom or a hydrocarbon group with 1 to 6 carbon atoms. It is preferable that the aforementioned halogen atom is a fluorine atom, chlorine atom, bromine atom, or iodine atom, with fluorine or iodine atom being more ideal. The hydrocarbon groups, hydrocarbon oxygen groups, hydrocarbon oxycarbonyl groups, and hydrocarbon thio groups can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be given as those exemplified with respect to the hydrocarbon groups represented by R22 and R23. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, the -CH2- group in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, it may contain hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonate ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc. When b2 is 2 or more, each R24 can be the same or different.

[0393] Furthermore, when b2 is 2 or more, the complex R24 groups can also bond with each other and form a ring together with the carbon atoms of the aromatic rings they are bonded to. Specific examples of the rings formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, and adamantane rings. Also, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, some of the -CH2- groups in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the rings 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)-), and haloalkyl groups.

[0394] Specific examples of the repeating unit a3 can be listed as shown below, but are not limited to these. Furthermore, in the following formula, RA is the same as described above, and Me is methyl. Also, the bonding positions of the various substituents on the aromatic ring can be interchanged. [Chemistry 333]

[0395] [Chemistry 334]

[0396] [Chemistry 335]

[0397] [Chemistry 336]

[0398] [Chemistry 337]

[0399] [Chemistry 338]

[0400] [Chemistry 339]

[0401] [Transformation 340]

[0402] [Chemistry 341]

[0403] [Chemistry 342]

[0404] [Chemistry 343]

[0405] [Chemistry 344]

[0406] [Chemistry 345]

[0407] [Chemistry 346]

[0408] [Chemistry 347]

[0409] [Chemistry 348]

[0410] [Chemistry 349]

[0411] [Chemical 350]

[0412] [Chemistry 351]

[0413] [Chemistry 352]

[0414] [Chemistry 353]

[0415] [Chemistry 354]

[0416] [Chemical 355]

[0417] [Chemical 356]

[0418] [Chemical 357]

[0419] [Chemical 358]

[0420] [Chemical 359]

[0421] [Chemical 360]

[0422] [Chemical 361]

[0423] [Chemical 362]

[0424] [Chemical 363]

[0425] [Chemical 364]

[0426] [Chemical 365]

[0427] [Chemical 366]

[0428] [Chemical 367]

[0429] [Chemical 368]

[0430] [Chemistry 369]

[0431] [Transformation 370]

[0432] [Chemistry 371]

[0433] [Chemistry 372]

[0434] [Chemistry 373]

[0435] [Chemistry 374]

[0436] [Chemistry 375]

[0437] [Chemistry 376]

[0438] [Chemistry 377]

[0439] [Chemistry 378]

[0440] [Chemistry 379]

[0441] [Chemistry 380]

[0442] [Chemistry 381]

[0443] [Chemistry 382]

[0444] Ideally, the aforementioned base polymer should contain 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.). [Chemistry 383]

[0445] In formulas (b1) and (b2), RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y1 is a single bond or *-C(=O)-O-. * indicates an atomic bond with a carbon atom in the main chain. R31 is a hydrogen atom, or a group with 1 to 20 carbon atoms containing at least one of the following: hydroxyl group other than a 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)-). R32 can be a halogen atom, hydroxyl group, carboxyl group, nitro group, cyano group, or may contain a hydrocarbon group with 1-20 carbon atoms, a hydrocarbon oxygen group with 1-20 carbon atoms, a hydrocarbon carbonyl group with 2-20 carbon atoms, a hydrocarbon carbonyl oxygen group with 2-20 carbon atoms, or a hydrocarbon oxygen carbonyl group with 2-20 carbon atoms. b is an integer from 1 to 4. c is an integer from 0 to 4. However, 1 ≤ b + c ≤ 5.

[0446] Specific examples of repeating unit b1 can be listed as shown below, but are not limited to these. Furthermore, in the following formula, RA is the same as described above. [Chem. 384]

[0447] [Chem. 385]

[0448] [Chemistry 386]

[0449] [Chemistry 387]

[0450] [Chem.388]

[0451] [Chemistry 389]

[0452] [Chemistry 390]

[0453] [Chemistry 391]

[0454] [Chemistry 392]

[0455] [Chemistry 393]

[0456] [Chem. 394]

[0457] [Chemistry 395]

[0458] [Chemistry 396]

[0459] [Chemistry 397]

[0460] [Chemistry 398]

[0461] [Chemistry 399]

[0462] Specific examples of the repeated unit b2 can be listed as shown below, but are not limited to these. Furthermore, in the following formula, RA is the same as described above. [Chemical 400]

[0463] [Chemical Engineering 401]

[0464] [Chemical 402]

[0465] [Chemical 403]

[0466] [Chemical 404]

[0467] Regarding repeating units b1 or b2, in ArF lithography, those with lactone rings as polar groups are more ideal, while in KrF lithography, EB lithography, and EUV lithography, those with phenolic sites are more ideal.

[0468] The aforementioned base polymer may further contain at least one of the repeating units selected from the following formula (c1) (hereinafter also referred to as repeating unit c1.), repeating units selected from the following formula (c2) (hereinafter also referred to as repeating unit c2.), repeating units selected from the following formula (c3) (hereinafter also referred to as repeating unit c3.), repeating units selected from the following formula (c4) (hereinafter also referred to as repeating unit c4.), and repeating units selected from the following formula (c5) (hereinafter also referred to as repeating unit c5.). [Chemical 405]

[0469] In formulas (c1) to (c5), RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z1 is a single bond or may be a phenyl group with substituents. Z2 is a single bond, **-C(=O)-O-Z21-, **-C(=O)-NH-Z21-, or **-O-Z21-. Z21 is an aliphatic phenyl group with 1 to 6 carbon atoms, a phenyl 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. Z3 is a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond. Z4 is a single bond, or an aliphatic alkyl group with 1 to 6 carbon atoms, an alkylphenyl group, or a divalent group obtained by combining them; it may also contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z5 is independently a single bond, or may contain a substituent such as an alkylphenyl group, an alkylnaphthyl group, or *-C(=O)-O-Z51-. Z51 is an aliphatic alkyl group with 1 to 10 carbon atoms, an alkylphenyl group, or an alkylnaphthyl group; this aliphatic alkyl group may also contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or a lactone ring. Z6 is a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond. Z7 can be a single bond, ***-Z71-C(=O)-O-, ***-C(=O)-NH-Z71-, or ***-O-Z71-. Z71 can also be a alkyl group with 1 to 20 carbon atoms containing heteroatoms. Z8 can be a single bond, ****-Z81-C(=O)-O-, ****-C(=O)-NH-Z81-, or ****-O-Z81-. Z81 can also be a alkyl group with 1 to 20 carbon atoms containing heteroatoms. Z9 can be a single bond, methylene, ethyl, phenyl, fluorinated phenyl, trifluoromethyl-substituted phenyl, *-C(=O)-O-Z91-, *-C(=O)-N(H)-Z91-, or *-O-Z91-. Z91 is an aliphatic phenyl group, phenylene oxide, fluorinated phenylene oxide, or phenylene oxide substituted with trifluoromethyl group, having 1 to 6 carbon atoms. It 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 Z1. *** indicates an atomic bond with Z6. **** indicates an atomic bond with Z7.

[0470] The aliphatic alkyl groups represented by Z21, Z51, and Z91 can be straight-chain, 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.

[0471] Z71 and Z81 can also contain heteroatoms, and the extended hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed as shown below, but are not limited to these. [Chemical 406] In the formula, the dashed lines represent atomic bonds.

[0472] In formula (c1), R41 and R42 are each independently a hydrocarbon group with 1 to 20 carbon atoms, which may also 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, dibutyl, and tributyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornel, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclohexenyl groups with 3 to 20 carbon atoms; aryl groups with 6 to 20 carbon atoms, such as phenyl, naphthyl, and thiophene; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them, but aryl is preferred. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, the -CH2- part of the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, it may contain hydroxyl, fluorine, chlorine, bromine, iodine, cyano, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonate ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc.

[0473] Furthermore, R41 and R42 can also bond to each other to form a ring together with the sulfur atoms they are bonded to. In this case, specific examples of the aforementioned rings can be listed as follows. [Chemical 407] In the formula, the dashed lines represent atomic bonds with Z4.

[0474] Specific examples of the cation in repeating unit c1 can be listed as shown below, but are not limited to these. Furthermore, in the following formula, RA is the same as described above. [Chemical 408]

[0475] [Chemical 409]

[0476] [Chemical 410]

[0477] [Chemistry 411]

[0478] [Chemistry 412]

[0479] [Chemistry 413]

[0480] [Chemistry 414]

[0481] [Chemical 415]

[0482] [Chemistry 416]

[0483] [Chemistry 417]

[0484] In formula (c1), M- represents a non-nucleophilic relative ion. Among the aforementioned non-nucleophilic relative ions, halide ions, sulfonic acid anions, acetylinic acid anions, and methylated acid anions are ideal. Specific examples of halide ions include chloride ions and bromide ions. Specific examples of sulfonic acid anions (sulfonate ions) include fluoroalkyl sulfonate ions such as trifluoromethanesulfonate ion, 1,1,1-trifluoroethanesulfonate ion, and nonafluorobutanesulfonate ion; aryl sulfonate ions such as toluenesulfonate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, and 1,2,3,4,5-pentafluorobenzenesulfonate ion; and alkyl sulfonate ions such as methanesulfonate ion and butanesulfonate ion. Specific examples of the aforementioned amide acid anions (amide ions) include bis(trifluoromethylsulfonyl)amide ions, bis(perfluoroethylsulfonyl)amide ions, and bis(perfluorobutylsulfonyl)amide ions. Specific examples of the aforementioned methylated acid anions (methylated ions) include trifluoromethylsulfonyl methylated ions and trifluoroethylsulfonyl methylated ions.

[0485] For other examples of the aforementioned non-nucleophilic relative ions, anions represented by any of the following formulas (c1-1) to (c1-4) can be listed. [Chemistry 418]

[0486] In formula (c1-1), Rfa is a fluorine atom, or a hydrocarbon group with 1 to 40 carbon atoms containing heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. For specific examples, those that are the same as those exemplified by the hydrocarbon group represented by Rfa1 in formula (c1-1-1) described later can be listed.

[0487] For anions represented by formula (c1-1), the one represented by formula (c1-1-1) is more ideal. [Chemistry 419]

[0488] In formula (c1-1-1), Q1 and Q2 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group with 1 to 6 carbon atoms. However, for the purpose of improving solvent solubility, at least one of them being trifluoromethyl is more ideal. m is an integer from 0 to 4, with 1 being particularly ideal. Rfa1 is a hydrocarbon group with 1 to 35 carbon atoms that may also contain heteroatoms. Regarding the aforementioned heteroatoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc., are more ideal, with oxygen atoms being even more ideal. Regarding the aforementioned hydrocarbon groups, considering the viewpoint of obtaining high resolution in the formation of fine patterns, those with 6 to 30 carbon atoms are particularly ideal.

[0489] In formula (c1-1-1), Rfa1 represents a hydrocarbon group with 1 to 35 carbon atoms, which can be saturated or unsaturated, and can be linear, branched, or cyclic. In specific examples, more ideally, alkyl groups with 1 to 35 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecanyl, and eicosyl; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norcamphenyl, norcamphenylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated aliphatic alkyl groups with 2 to 35 carbon atoms include allyl and 3-cyclohexenyl; aryl groups with 6 to 35 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, and 9-enyl; aralkyl groups with 7 to 35 carbon atoms include benzyl and diphenylmethyl; and groups obtained by combining these.

[0490] Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, the -CH2- part of the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, it may contain hydroxyl, fluorine, chlorine, bromine, iodine, cyano, nitro, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulopentalide ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc. Specific examples of hydrocarbon groups containing heteroatoms include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetaminomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-sideoxypropyl, 4-sideoxy-1-adamantyl, 3-sideoxycyclohexyl, etc.

[0491] In formula (c1-1-1), La1 can be a single bond, ether bond, ester bond, sulfonate bond, carbonate bond or carbamate bond. However, from a synthetic point of view, an ether bond or an ester bond is more ideal, and an ester bond is even more ideal.

[0492] Specific examples of anions represented by formula (c1-1) are shown below, but are not limited to these. Furthermore, in the following formula, Q1 is the same as described above, and Ac is acetyl. [Chemistry 420]

[0493] [Chemistry 421]

[0494] [Chemistry 422]

[0495] [Chemistry 423]

[0496] [Chemistry 424]

[0497] [Chemical 425]

[0498] [Chemistry 426]

[0499] [Chemistry 427]

[0500] [Chemistry 428]

[0501] [Chemistry 429]

[0502] In formula (c1-2), Rfb1 and Rfb2 are each independently a fluorine atom, or may contain heteroatoms and be a hydrocarbon group with 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 as those exemplified in formula (c1-1-1) for the hydrocarbon group represented by Rfa1. Ideally, Rfb1 and Rfb2 should be fluorine atoms or linear fluorinated alkyl groups with 1 to 4 carbon atoms. Furthermore, Rfb1 and Rfb2 can also bond to each other and form a ring with the group they are bonded to (-CF2-SO2-N--SO2-CF2-). In this case, the group obtained by the mutual bonding of Rfb1 and Rfb2 should ideally be fluorinated ethyl or fluorinated propyl.

[0503] In formula (c1-3), Rfc1, Rfc2, and Rfc3 are each independently a fluorine atom, or may contain heteroatoms and be a hydrocarbon group with 1 to 40 carbon atoms. The aforementioned hydrocarbon groups can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed as those exemplified in formula (c1-1-1) for the hydrocarbon group represented by Rfa1. For Rfc1, Rfc2, and Rfc3, it is ideal to be a fluorine atom or a linear fluorinated alkyl group with 1 to 4 carbon atoms. Furthermore, Rfc1 and Rfc2 can also bond to each other to form a ring with the group they are bonded to (-CF2-SO2-C--SO2-CF2-). In this case, the group obtained by the mutual bonding of Rfc1 and Rfc2 is preferably a fluorinated ethyl or fluorinated propyl group.

[0504] In formula (c1-4), Rfd is a hydrocarbon group with 1 to 40 carbon atoms, which may also contain heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. For specific examples, those that are the same as those exemplified by the hydrocarbon group represented by Rfa1 in formula (c1-1-1) can be listed.

[0505] Specific examples of anions represented by formula (c1-4) can be listed as shown below, but are not limited to these. [Chemistry 430]

[0506] [Chemistry 431]

[0507] Regarding the aforementioned examples of non-nucleophilic relative ions, further examples include anions having aromatic rings substituted with iodine or bromine atoms. Specific examples of such anions can be represented by the following formula (c1-5). [Chemistry 432]

[0508] 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. Ideally, y should be an integer satisfying 1 ≤ y ≤ 3, and 2 or 3 would be even more ideal. Ideally, z should be an integer satisfying 0 ≤ z ≤ 2.

[0509] In formula (c1-5), XBI is an iodine atom or a bromine atom, and when x and / or y are 2 or more, they can be the same or different.

[0510] In formula (c1-5), L1 is a single bond, ether bond, or ester bond, or may contain a saturated alkyl group with 1 to 6 carbon atoms that is an ether bond or ester bond. The aforementioned saturated alkyl group may be linear, branched, or cyclic.

[0511] In formula (c1-5), L2 is a single bond or a divalent linker with 1 to 20 carbon atoms when x is 1, and a (x+1) valent linker with 1 to 20 carbon atoms when x is 2 or 3. The linker may also contain oxygen, sulfur or nitrogen atoms.

[0512] In formula (c1-5), Rfe is a hydroxyl, carboxyl, fluorine, chlorine, bromine, or amino group, or may contain a 1-20 carbon-1 hydrocarbon group, a 1-20 carbon-1 hydrocarbon oxygen group, a 2-20 carbon-2 hydrocarbon carbonyl group, a 2-20 carbon-2 hydrocarbon oxycarbonyl group, a 2-20 carbon-2 hydrocarbon carbonyl oxygen group, or a 1-20 carbon-1 hydrocarbon sulfonyl oxygen group, or -N(RfeA)(RfeB), -N(RfeC)-C(=O)-RfeD or -N(RfeC)-C(=O)-O-RfeD. RfeA and RfeB are each independently a hydrogen atom or a 1-6 carbon-1 saturated hydrocarbon group. RfeC is a hydrogen atom or a saturated hydrocarbon group with 1 to 6 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxygen group with 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group with 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl group with 2 to 6 carbon atoms. RfeD 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 oxygen group with 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group with 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl group with 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. The aforementioned hydrocarbon groups, hydrocarbon oxygen groups, hydrocarbon carbonyl groups, hydrocarbon oxycarbonyl groups, hydrocarbon carbonyl groups, and hydrocarbon sulfonyl groups may be linear, branched, or cyclic. When x and / or z are 2 or more, each Rfe may be the same or different.

[0513] Among these, for Rfe, hydroxyl, -N(RfeC)-C(=O)-RfeD, -N(RfeC)-C(=O)-O-RfeD, fluorine atom, chlorine atom, bromine atom, methyl, methoxy, etc. are more ideal.

[0514] In formula (c1-5), Rf11 to Rf14 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of them is a fluorine atom or a trifluoromethyl group. Furthermore, Rf11 and Rf12 can also combine to form a carbonyl group. Ideally, both Rf13 and Rf14 should be fluorine atoms.

[0515] Specific examples of anions represented by formula (c1-5) can be listed as shown below, but are not limited to these. Furthermore, in the following formula, XBI is the same as described above. [Chemistry 433]

[0516] [Chemistry 434]

[0517] [Chemistry 435]

[0518] [Chemistry 436]

[0519] [Chemistry 437]

[0520] [Chemistry 438]

[0521] [Chemistry 439]

[0522] [Chemistry 440]

[0523] [Chemistry 441]

[0524] [Chemistry 442]

[0525] [Chemistry 443]

[0526] [Chemistry 444]

[0527] [Chemistry 445]

[0528] [Chemistry 446]

[0529] [Chemistry 447]

[0530] [Chemistry 448]

[0531] [Chemistry 449]

[0532] [Chemistry 450]

[0533] [Chemistry 451]

[0534] [Chemistry 452]

[0535] [Chemistry 453]

[0536] [Chemistry 454]

[0537] [Chemistry 455]

[0538] Regarding the aforementioned non-nucleophilic relative ions, the following can also be used: the fluorobenzenesulfonic acid anion bonded to an aromatic group containing an iodine atom as described in Japanese Patent No. 6648726; the anion with a mechanism of decomposition by acid as described in International Publication No. 2021 / 200056 and Japanese Patent Application Publication No. 2021-70692; the anion with a cyclic ether group as described in Japanese Patent Application Publication No. 2018-180525 and Japanese Patent Application Publication No. 2021-35935; and the anion as described in Japanese Patent Application Publication No. 2018-92159.

[0539] Regarding the aforementioned non-nucleophilic relative ions, the anions of fluorine-free, bulky benzenesulfonic acid derivatives described in Japanese Patent Application Publication No. 2006-276759, Japanese Patent Application Publication No. 2015-117200, Japanese Patent Application Publication No. 2016-65016 and Japanese Patent Application Publication No. 2019-202974, as well as the fluorine-free benzenesulfonic acid anions and alkylsulfonic acid anions bonded to an aromatic group containing an iodine atom described in Japanese Patent No. 6645464, may also be used.

[0540] Regarding the aforementioned non-nucleophilic relative ions, the anions of disulfonic acid described in Japanese Patent Application Publication No. 2015-206932, the anions of sulfonamide and sulfenimine described in International Patent Application Publication No. 2020 / 158366 which are sulfonic acid on one side and different from it on the other side, and the anions of carboxylic acid on one side described in Japanese Patent Application Publication No. 2015-24989, which are sulfonic acid on one side and carboxylic acid on the other side, can also be used.

[0541] In equations (c2) and (c3), d1 and d2 are each independently 0, 1, 2 or 3, but 1 is more ideal.

[0542] In equation (c4), e1 is 0 or 1. e2 is an integer from 0 to 4. e3 is an integer from 0 to 4. However, when e1 is 0, 0 ≦ e2 + e3 ≦ 4, and when e1 is 1, 0 ≦ e2 + e3 ≦ 6.

[0543] In formulas (c2), (c3), and (c4), L1 can be a single bond, ether bond, ester bond, carbonyl group, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. From a synthetic perspective, ether bonds, ester bonds, and carbonyl groups are more ideal, with ester bonds and carbonyl groups being even more ideal.

[0544] In formula (c2), Rf1 and Rf2 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Among these, for Rf1 and Rf2, it is more desirable for them to be fluorine atoms in order to improve the acid strength of the resulting acid. Rf3 and Rf4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Among these, it is more desirable for at least one of Rf3 and Rf4 to be trifluoromethyl in order to improve solvent solubility.

[0545] In formula (c3), Rf5 and Rf6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. However, not all of Rf5 and Rf6 are hydrogen atoms simultaneously. Among these, it is more ideal for at least one of Rf5 and Rf6 to be trifluoromethyl for improved solvent solubility.

[0546] In formula (c4), Rf7 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 alkyl thio group having 1 to 6 carbon atoms. Ideally, Rf7 should be a fluorine atom, trifluoromethyl, difluoromethyl, trifluoromethoxy, difluoromethoxy, trifluoromethylthio, or difluoromethylthio, with fluorine atom, trifluoromethyl, or trifluoromethoxy being more ideal. When f is 2, 3, or 4, each Rf7 can be the same or different.

[0547] In formula (c4), R43 is a halogen atom other than fluorine, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed as those exemplified in the description of formula (1A) for hydrocarbon groups represented by R1, but are not limited to these. Furthermore, when e3 is 2, 3, or 4, each R43 can be the same or different.

[0548] Furthermore, when e3 is 2, 3, or 4, the complex R43 can also bond with each other to form a ring together with the carbon atoms they bond to. Specific examples of the rings formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, and adamantane rings. Also, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, some of the -CH2- groups in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the rings 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)-), and haloalkyl groups.

[0549] Specific examples of the anion in repeating unit c2 can be listed as shown below, but are not limited to these. Furthermore, in the following formula, RA is the same as described above, and Me is a methyl group. [Chemistry 456]

[0550] [Chemistry 457]

[0551] [Chemistry 458]

[0552] [Chemistry 459]

[0553] [Chemistry 460]

[0554] [Chemistry 461]

[0555] [Chemistry 462]

[0556] [Chemistry 463]

[0557] [Chemistry 464]

[0558] Specific examples of the anion in repeating unit c3 can be listed as shown below, but are not limited to these. Furthermore, in the following formula, RA is the same as described above. [Chemistry 465]

[0559] [Chemistry 466]

[0560] [Chemistry 467]

[0561] [Chemistry 468]

[0562] [Chemistry 469]

[0563] [Chemistry 470]

[0564] [Chemistry 471]

[0565] [Chemistry 472]

[0566] Specific examples of the anion in repeating unit c4 can be listed as shown below, but are not limited to these. Furthermore, in the following formula, RA is the same as described above. [Chemistry 473]

[0567] [Chemistry 474]

[0568] [Chemistry 475]

[0569] [Chemistry 476]

[0570] [Chemistry 477]

[0571] [Chemistry 478]

[0572] [Chemistry 479]

[0573] [Chemistry 480]

[0574] [Chemistry 481]

[0575] [Chemistry 482]

[0576] [Chemistry 483]

[0577] [Chemistry 484]

[0578] [Chemistry 485]

[0579] Specific examples of anions in the repeating unit c5 can be listed as shown below, but are not limited to these. Furthermore, in the following formula, RA is the same as described above. [Chemistry 486]

[0580] In formulas (c2) to (c5), A+ is an onium cation. Examples of onium cations include strontium cations, ferrophosphate cations, and ammonium cations, but strontium cations and ferrophosphate cations are preferred. Specific examples of strontium cations include those described in paragraphs

[0102] to

[0125] of Japanese Patent Application Publication No. 2024-003744, those described in paragraphs

[0070] to

[0085] of Japanese Patent Application Publication No. 2023-169812, and those represented by formula (1B), but are not limited to these. Specific examples of ferrophosphate cations include those described in paragraph

[0181] of Japanese Patent Application Publication No. 2024-000259, but are not limited to these. Regarding the specific examples of the aforementioned ammonium cations, examples that are the same as those exemplified below in the form of ammonium cations represented by formula (am-1) may be listed, but are not limited to these.

[0581] Regarding the specific structure of the repeating units c1 to c5, any combination of anions and cations as described above can be listed.

[0582] Among the repeating units c1 to c5, considering the control of acid diffusion, repeating units c2 to c5 are more ideal; considering the acid strength of the produced acid, repeating units c2, c4, and c5 are more ideal; and considering the solvent solubility, repeating unit c2 is more ideal.

[0583] The aforementioned basic 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 is no particular limitation as long as they have a structure in which one or two or more hydroxyl groups are protected and the protecting groups decompose and generate hydroxyl groups due to the action of acid. It is more ideal for them to be represented by the following formula (d1). [Chemistry 487]

[0584] In formula (d1), the RA group is the same as described above. R51 is a (f+1) valence hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. R52 is an acid-labile group. f is an integer from 1 to 4.

[0585] In formula (d1), the acid-labile group represented by R52 may be any group that can be deprotected by the action of an acid to generate a hydroxyl group. The structure of R52 is not particularly limited, and an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (d2), etc. are preferable, and an alkoxymethyl group represented by the following formula (d2) is particularly preferable. [Chemical formula 488] In the formula, * represents an atomic bond. R53 is a hydrocarbon group having 1 to 15 carbon atoms.

[0586] Specific examples of the acid-labile group represented by R52, the alkoxymethyl group represented by formula (d2), and the repeating unit d may be the same as those exemplified in the description of the repeating unit d in Japanese Patent Application Laid-Open No. 2020-111564.

[0587] The aforementioned base polymer may further contain a repeating unit e derived from indene, benzofuran, benzothiophene, acenaphthene, chromone, coumarin, norbornadiene, or their derivatives. Specific examples of the monomer that provides the repeating unit e may be as shown below, but are not limited thereto. [Chemical formula 489]

[0588] The aforementioned base polymer may further contain a repeating unit f derived from indan, vinylpyridine, or vinylcarbazole.

[0589] 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 + c5 + d + e + f ≤ 1.0.

[0590] Ideally, the weight-average molecular weight (Mw) of the aforementioned polymer should be between 1,000 and 500,000, with 3,000 to 100,000 being even more ideal. If Mw falls within this range, sufficient etching resistance can be obtained, and there is no risk of reduced resolution due to the difference in dissolution rates before and after exposure. Furthermore, in this invention, Mw is a polystyrene-converted value determined using a gel permeation chromatography (GPC) system employing THF or N,N-dimethylformamide (DMF) as solvents.

[0591] Then, regarding the aforementioned molecular weight distribution (Mw / Mn) of the polymer, as the pattern regularity becomes finer, the influence of Mw / Mn tends to increase. Therefore, in order to obtain a resist composition that can be ideally used in fine pattern sizes, a narrow dispersion of Mw / Mn of 1.0 to 2.0 is more desirable. Within this range, there are fewer low-molecular-weight and high-molecular-weight polymers, and there is no risk of foreign matter being found on the pattern or the shape of the pattern deteriorating after exposure.

[0592] In the synthesis of the aforementioned polymer, for example, the monomer that provides the aforementioned repeating unit can be added to an organic solvent with a free radical polymerization initiator and heated to carry out polymerization.

[0593] Specific examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, dialkylene, 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 lauryl peroxide. The ideal amount of these initiators relative to the total monomers used in polymerization is 0.01–25 mol%. The ideal reaction temperature is 50–150 °C, and more ideally 60–100 °C. A reaction time of 2 to 24 hours is ideal, but from the perspective of production efficiency, 2 to 12 hours is even more ideal.

[0594] The aforementioned polymerization initiator can be added to the monomer solution and then supplied to the reactor, or a separate initiator solution can be prepared and supplied to the reactor independently. During the standby time, there is a possibility that polymerization may occur due to free radicals generated by the initiator, resulting in the formation of ultrapolymers. Therefore, from a quality management perspective, it is ideal to prepare the monomer solution and initiator solution independently and add them dropwise. Acid-labile groups can be used directly as introduced into the monomer, or they can be used for post-polymerization protection or partial protection. Furthermore, for molecular weight adjustment, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can be used. In this case, the amount of these chain transfer agents added relative to the total amount of monomers used for polymerization is ideally 0.01~20 mol%.

[0595] 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. Then, deprotection can be carried out by weak acid and water after polymerization. Alternatively, they can be replaced with acetyl, methyl, trimethylacetyl, etc., and then alkaline hydrolysis can be carried out after polymerization.

[0596] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene can be copolymerized with other monomers in an organic solvent by adding a free radical polymerization initiator and heating. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene can be used, and the acetoxy group can be deprotected by alkaline hydrolysis after polymerization to produce polyhydroxystyrene or hydroxyvinylnaphthalene.

[0597] For the alkali used in alkaline hydrolysis, ammonia, triethylamine, etc., can be used. Furthermore, the ideal reaction temperature is -20~100℃, and even more ideally 0~60℃. The ideal reaction time is 0.2~100 hours, and even more ideally 0.5~20 hours.

[0598] In addition, the amount of each monomer in the aforementioned monomer solution can be appropriately set, for example, in a manner that would constitute a preferred content ratio for the aforementioned repeating unit.

[0599] The polymer obtained by the aforementioned manufacturing method can be used as the final product by the reaction solution obtained through the polymerization reaction, or the polymer solution can be added to a lean solvent and the powder obtained through refining steps such as reprecipitation to obtain powder can be used as the final product. However, considering the perspective of work efficiency and quality stability, it is more ideal to use the polymer solution obtained by dissolving the powder obtained through the refining step in the solvent as the final product.

[0600] Specific examples of solvents used at this time include ketones such as cyclohexanone and methyl-2-n-pentyl ketone, as described in paragraphs

[0144] to

[0145] of Japanese Patent Application Publication No. 2008-111103; 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, tributyl acetate, tributyl propionate, and propylene glycol monobutyl 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.

[0601] In the aforementioned polymer solution, a polymer concentration of 0.01 to 30% by mass is ideal, and 0.1 to 20% by mass is even more ideal.

[0602] The aforementioned reaction solutions and polymer solutions are ideally filtered using filter media. By using filter media, foreign matter and gel that could cause defects can be removed, which is effective in ensuring quality stability.

[0603] Regarding the materials used in the aforementioned filter media filtration, examples include fluorocarbon, cellulose, nylon, polyester, and hydrocarbon-based materials. However, in the filtration step involving inhibitor components, filter media formed from fluorocarbons (such as Teflon, a registered trademark), polyethylene, polypropylene, or nylon are more ideal. The pore size of the filter media can be appropriately selected according to the target cleanliness level, ideally below 100 nm, and even more ideally below 20 nm. Furthermore, these filter media can be used individually or in combination. Regarding the filtration method, the solution can be filtered only once, but circulating the solution for multiple filtrations is more ideal. The filtration steps can be performed in any order and number of times during the polymer manufacturing process; filtering the reaction solution, polymer solution, or both after the polymerization reaction is more ideal.

[0604] (B) A single base polymer may be used alone, or two or more polymers with different composition ratios, Mw and / or Mw / Mn ratios may be used in combination. Furthermore, (B) the base polymer may contain hydrides of ring-opening metathesis polymers in addition to the aforementioned polymers; in this regard, those described in Japanese Patent Application Publication No. 2003-66612 may be used.

[0605] [(C) Organic solvent] The chemical amplification inhibitor composition of the present invention may also contain an organic solvent as component (C). As for the organic solvent (C), there is no particular limitation as long as it can dissolve the aforementioned components and the components described below. Specific examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; 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, tributyl acetate, tributyl propionate, and propylene glycol monotertyl ether acetate; lactones such as GBL; and mixed solvents thereof.

[0606] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and their mixed solvents are particularly ideal as they have excellent solubility for the base polymer of component (B).

[0607] In the chemical amplification inhibitor composition of this invention, the content of (C) organic solvent is ideally 200-5000 parts by mass relative to 80 parts by mass of (B) base polymer, and even more ideally 400-3500 parts by mass. (C) Organic solvent can be used alone or in combination of two or more.

[0608] [(D) Quenching agent] The chemical amplification inhibitor composition of the present invention may also contain a quencher as component (D). In addition, the quencher referred to in the present invention is a material used to capture the acid generated by the photoacid generator in the chemical amplification inhibitor composition, thereby preventing it from diffusing to the unexposed area and forming the desired pattern.

[0609] Regarding (D) quenchers, examples of onium salts represented by formulas (2) or (3) can be listed below. [Chemistry 490]

[0610] In formula (2), Rq1 is a hydrogen atom, or may contain a hydrocarbon group with 1 to 40 carbon atoms containing heteroatoms, except where the hydrogen atom at the α-position of the sulfonic acid group is replaced by a fluorine atom or a fluoroalkyl group. In formula (3), Rq2 is a hydrogen atom, or may contain a hydrocarbon group with 1 to 40 carbon atoms containing heteroatoms.

[0611] Specifically, the hydrocarbon groups with 1 to 40 carbon atoms represented by Rq1 can be exemplified by alkyl groups with 1 to 40 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, tripentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norcamphenyl, tricyclo[5.2.1.02,6]decyl, and adamantylalkyl; and 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 group can be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, the -CH2- part of the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, it may contain hydroxyl, fluorine, chlorine, bromine, iodine, cyano, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonate ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc.

[0612] Regarding the specific hydrocarbon group represented by Rq2, in addition to the substituents exemplified in the specific example of Rq1, fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl can also be listed.

[0613] Specific examples of onium salt anions represented by equation (2) can be listed as shown below, but are not limited to these. [Chemistry 491]

[0614] [Chemistry 492]

[0615] [Chemistry 493]

[0616] [Chemistry 494]

[0617] [Chemistry 495]

[0618] Specific examples of onium salt anions represented by equation (3) can be listed as shown below, but are not limited to these. [Chemistry 496]

[0619] [Chemistry 497]

[0620] [Chemistry 498]

[0621] [Chemistry 499]

[0622] [Chemical 500]

[0623] In equations (2) and (3), Mq+ represents an onium cation. Examples of onium cations include strontium cations, ferrophosphate cations, and ammonium cations. Specific examples of strontium and ferrophosphate cations include those identical to those exemplified in the descriptions of equations (c2) to (c5) for strontium and ferrophosphate cations represented by A+, but are not limited to these. Specific examples of ammonium cations include those represented by the following equation (am-1). [Chemical 501]

[0624] In formula (am-1), Rq11 to Rq14 are each independently a hydrocarbon group with 1 to 40 carbon atoms, which may also contain heteroatoms. Furthermore, Rq11 and Rq12 may also bond to each other and form a ring together with the nitrogen atoms they are bonded to. Specific examples of the aforementioned hydrocarbon groups can be listed as those identical to those exemplified in the description of the hydrocarbon group represented by R1 in formula (1A).

[0625] Specific examples of ammonium cations represented by formula (am-1) can be listed as shown below, but are not limited to these. [Chemical 502]

[0626] For specific examples of onium salts represented by formula (2) or (3), any combination of anions and cations as described above can be listed. Furthermore, these onium salts can be readily prepared by ion exchange reactions using known organic chemical methods. Regarding ion exchange reactions, Japanese Patent Application Publication No. 2007-145797 can be referenced, for example.

[0627] The onium salts represented by formula (2) or (3) function as quenchers in the chemical amplification inhibitor composition of the present invention. This is because the relative anions of the aforementioned onium salts are conjugate bases of weak acids. Here, a weak acid is defined as an acidity that cannot deprotect the acid-instable groups of units containing acid-instable groups used in the base polymer. When the onium salts represented by formula (2) or (3) are used in combination with a conjugate base of a strong acid, such as an α-fluorinated sulfonic acid, as a relative anion of an onium salt-type photoacid generator, they function as quenchers. In other words, when onium salts that produce strong acids like α-fluorinated sulfonic acid are mixed with onium salts that produce weak acids like unfluorinated sulfonic acid and carboxylic acid, if the strong acid generated from the photoacid generator due to high-energy radiation reacts with the onium salt containing unreacted weak acid anions, the weak acid will be released through salt exchange, generating an onium salt containing strong acid anions. Through this process, the strong acid is exchanged for a weaker acid with lower catalytic energy, so the acid appears to be deactivated, allowing for controlled acid diffusion.

[0628] Furthermore, regarding the quencher (D), the onium salt having strontium cation and benzene oxide anion sites in the same molecule as described in Japanese Patent No. 6848776, the onium salt having strontium cation and carboxylic acid ester anion sites in the same molecule as described in Japanese Patent No. 6583136 and Japanese Patent Application Publication No. 2020-200311, and the onium salt having monium cation and carboxylic acid ester anion sites in the same molecule as described in Japanese Patent No. 6274755 are also applicable.

[0629] Here, when the photoacid generator that produces a strong acid is an onium salt, as mentioned above, the strong acid generated by high-energy ray irradiation will exchange into a weak acid. However, on the other hand, it is believed that the weak acid generated by high-energy ray irradiation is not likely to react with the unreacted onium salt that produces a strong acid and undergo salt exchange. This is because onium cations readily form ion pairs with the anions of stronger acids.

[0630] When the chemical amplification inhibitor composition of the present invention includes an onium salt represented by formula (2) or (3) as the quencher of (D), its content is ideally 0.1 to 20 parts by mass relative to 80 parts by mass of the base polymer of (B), and even more ideally 0.1 to 10 parts by mass. If the onium salt type quencher of component (D) falls within the aforementioned range, the resolution is good and there is no risk of significant reduction in sensitivity, which is therefore ideal. The onium salt represented by formula (2) or (3) can be used alone or in combination of two or more.

[0631] The chemical amplification inhibitor composition of the present invention may also contain a nitrogen-containing compound as a (D) quencher. Regarding the nitrogen-containing compound of the (D) component, examples include first-, second-, or third-order amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Publication No. 2008-111103, particularly amine compounds having hydroxyl groups, ether bonds, ester bonds, lactone rings, cyano groups, or sulfonate bonds. Furthermore, compounds formed by protecting a first- or second-order amine with a carbamate group, as described in Japanese Patent No. 3790649, may also be cited.

[0632] Furthermore, regarding nitrogen-containing compounds, strontium sulfonate salts with nitrogen-containing substituents can also be used. This type of compound functions as a quencher in the unexposed area, while in the exposed area, it loses its quencher properties due to neutralization with the acid it generates, and functions as a so-called photodegrading base. By using a photodegrading base, the contrast between the exposed and unexposed areas can be enhanced. For example, Japanese Patent Application Laid-Open Nos. 2009-109595 and 2012-46501 can be referenced regarding photodegrading bases.

[0633] When the chemical amplification inhibitor composition of the present invention contains a nitrogen-containing compound as a (D) quencher, its content is ideally 0.001 to 12 parts by mass relative to 80 parts by mass of the (B) base polymer, and even more ideally 0.01 to 8 parts by mass. The aforementioned nitrogen-containing compound can be used alone or in combination of two or more.

[0634] [(E) Other photoacid generating agents] The chemical amplification inhibitor 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). As for other photoacid generators, there is no particular limitation as long as they are compounds that can generate acid when irradiated by high-energy rays. Ideal other photoacid generators can be represented by the following formulas (4) or (5). [Chemical 503]

[0635] In formula (4), R101 to R105 are each independently a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. Furthermore, any two of R101, R102 and R103 may bond to each other and form a ring together with the sulfur atoms they are bonded to.

[0636] Regarding specific examples of strontium salt cations represented by formula (4) and ferrous salt cations represented by formula (5), examples that are the same as those exemplified in the descriptions of formulas (c2) to (c5) for strontium cations and ferrous cations represented by A+ can be listed, but are not limited to these.

[0637] In equations (4) and (5), Xa- is the anion of a strong acid. As for the aforementioned anions of strong acids, any of the ones represented in equations (c1-1) to (c1-5) can be listed.

[0638] Furthermore, for other photoacid generators of component (E), those represented by the following formula (6) are also more ideal. [Chemical 504]

[0639] In formula (6), R201 and R202 are each independently a hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. R203 is an extended hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. Furthermore, any two of R201, R202 and R203 may bond to each other and form a ring together with the sulfur atoms they are bonded to.

[0640] R201 and R202 represent hydrocarbon groups with 1 to 30 carbon atoms, which 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, dibutyl, tributyl, tripentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornel, oxanorbornel, and tricyclic [5.2.1.02]. [6] Decyl, adamantyl, and other cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms; phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, dibutylphenyl, tributylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, dibutylnaphthyl, tributylnaphthyl, anthracene, and other aryl groups with 6 to 30 carbon atoms; and groups obtained by combining them. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, the -CH2- group in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, it may contain hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulopentalide ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc.

[0641] R203 indicates that the carbon groups (1-30) 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; cyclopentanediyl, cyclohexanediyl, norcamphenediyl, adamantanediyl, and other cyclic saturated alkyl groups with 3 to 30 carbon atoms; and aryl groups such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, dibutylphenylene, tributylphenylene, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, dibutylnaphthyl, and tributylnaphthyl. Furthermore, some or all of the hydrogen atoms in the aforementioned alkyl group can be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, the -CH2- portion of the aforementioned alkyl group can be replaced by a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, it can contain hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonate ring, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups. Regarding the aforementioned heteroatoms, oxygen atoms are most ideal.

[0642] In formula (6), LA is a single bond, an ether bond, or may contain a heteroatom of 1 to 20 carbon atoms in an extended hydrocarbon group. The aforementioned extended hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. For specific examples, examples that are the same as those exemplified with respect to the extended hydrocarbon group represented by R203 can be listed.

[0643] In formula (6), Xa, Xb, Xc and Xd are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl atom. However, at least one of Xa, Xb, Xc and Xd is a fluorine atom or a trifluoromethyl atom.

[0644] Regarding the photoacid generator represented by formula (6), the one represented by formula (6') is more ideal. [Chemical 505]

[0645] In formula (6'), LA is the same as described above. Xe is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R301, R302, and R303 are each independently hydrogen atoms, or may contain heteroatoms of 1 to 20 carbon atoms in a hydrocarbon group. The aforementioned hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. For specific examples, those identical to those exemplified in formula (c1-1-1) for the hydrocarbon group represented by Rfa1 can be listed. p and q are each independently integers from 0 to 5, and r is an integer from 0 to 4.

[0646] Regarding the photoacid generator represented by formula (6), examples can be listed that are the same as those exemplified in Japanese Patent Application Publication No. 2017-26980, which represents the photoacid generator represented by formula (2).

[0647] 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 ideal. Furthermore, those represented by formula (6') exhibit extremely low acid diffusion, making them particularly ideal.

[0648] When the chemical amplification inhibitor composition of this invention includes other photoacid generating agents (E), their content is ideally 0.1 to 40 parts by mass relative to 80 parts by mass of the base polymer (B), and more ideally 0.5 to 20 parts by mass. If the amount of photoacid generating agent added in component (E) falls within the aforementioned range, the resolution is good, and there is no risk of foreign matter problems arising after development or peeling of the inhibitor film, which is therefore ideal. Other photoacid generating agents (E) can be used alone or in combination of two or more.

[0649] (F) Surfactants The chemical amplification inhibitor composition of the present invention may further contain a surfactant as component (F). Regarding the surfactant (F), it is preferable to have 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.

[0650] Regarding surfactants that are insoluble or poorly soluble in water and alkaline developing solutions, among the surfactants described in the aforementioned publication, FC-4430 (manufactured by 3M), Surflon (registered trademark) S-381 (manufactured by AGC SEIMI CHEMICAL), Olfine (registered trademark) E1004 (manufactured by Nissin Chemical Industry), KH-20, KH-30 (manufactured by AGC SEIMI CHEMICAL), and the oxane ring-opening polymer represented by the following formula (surf-1) are particularly ideal. [Chemical 506]

[0651] Here, R, Rf, A, B, C, m, and n are not related to the aforementioned descriptions, but only apply to formula (surf-1). R is an aliphatic group with 2 to 5 carbon atoms in a 2 to 4-valent configuration. Regarding the aforementioned aliphatic groups, examples of 2-valent groups include ethylenyl, 1,4-butylenyl, 1,2-propylenyl, 2,2-dimethyl-1,3-propylenyl, and 1,5-pentylenyl, while examples of 3- or 4-valent groups include the following. [Chem. 507] In the formula, the dashed lines represent atomic bonds, each of which is a secondary structure derived from glycerol, trimethylolethane, trimethylolpropane, and neopentyl tertrol.

[0652] Among these, 1,4-endobutyl and 2,2-dimethyl-1,3-endopropyl are more ideal.

[0653] Rf is trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. m is an integer from 0 to 3, n is an integer from 1 to 4, and the sum of n and m is the valence of R, which is an integer from 2 to 4. A is 1. B is an integer from 2 to 25, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. Furthermore, the arrangement of the constituent units in formula (surf-1) is not limited; they can be block-bonded or random-bonded. For details on the manufacture of surfactants in partially fluorinated oxyheterocyclic butane ring-opening polymer systems, please refer to the specification of US Patent No. 5650483, etc.

[0654] Surfactants that are insoluble or sparingly soluble in water but soluble in alkaline developing solutions are useful when ArF wet photolithography is performed without a resist protective film. They reduce water penetration and leaching by aligning to the surface of the resist film. Therefore, they are useful for inhibiting the leaching of water-soluble components from the resist film and reducing damage to the exposure equipment. Furthermore, they are useful because they dissolve in alkaline aqueous solutions after exposure or post-exposure baking (PEB) and do not easily form foreign matter that could cause defects. These surfactants, which are insoluble or sparingly soluble in water but soluble in alkaline developing solutions, are polymeric surfactants, also known as hydrophobic resins. Those with high water-repellent properties and improved hydrophobicity are particularly desirable.

[0655] Specific examples of such polymeric surfactants include those containing at least one repeating unit selected from any of the following formulas (7A) to (7E). [Chem.508]

[0656] In formulas (7A) to (7E), RB is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. W1 is -CH2-, -CH2CH2-, -O-, or two separate -H groups. Rs1 is each independently a hydrogen atom or a hydrocarbon group with 1 to 10 carbon atoms. Rs2 is a single bond or a straight-chain or branched hydrocarbon group with 1 to 5 carbon atoms. Rs3 is each independently a hydrogen atom, a hydrocarbon group with 1 to 15 carbon atoms, a fluorinated hydrocarbon group, or an acid-unstable group. When Rs3 is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may also be present between the carbon-carbon bonds. Rs4 is a (u+1) valence hydrocarbon group or a fluorinated hydrocarbon group with 1 to 20 carbon atoms. u is an integer from 1 to 3. Rs5 is each independently a hydrogen atom or a group represented by -C(=O)-O-Rsa. Rsa is a fluorinated hydrocarbon group with 1 to 20 carbon atoms. Rs6 is a hydrocarbon group or fluorinated hydrocarbon group with 1 to 15 carbon atoms, and its carbon-carbon bonds may be separated by ether bonds or carbonyl groups.

[0657] Rs1 represents a hydrocarbon group with 1 to 10 carbon atoms, ideally a saturated hydrocarbon group, which 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, dibutyl, tributyl, 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, 1 to 6 carbon atoms are preferred.

[0658] Ideally, the alkyl group represented by Rs2 should be a saturated alkyl group, which can be linear, branched, or cyclic. Specific examples include methylene, ethyl alkyl, propyl alkyl, butyl alkyl, and pentyl alkyl.

[0659] The hydrocarbon groups represented by Rs3 or Rs6 can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include aliphatic unsaturated hydrocarbon groups such as saturated hydrocarbon groups, alkenyl groups, and alkynyl groups, but saturated hydrocarbon groups are preferred. Regarding the aforementioned saturated hydrocarbon groups, in addition to those exemplified by the hydrocarbon groups represented by Rs1, examples include undecyl, dodecyl, tridecyl, tetradecyl, and pentadecyl. Regarding the fluorinated hydrocarbon groups represented by Rs3 or Rs6, examples include groups where 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, these carbon-carbon bonds can also be separated by ether bonds or carbonyl groups.

[0660] Specific examples of acid-instable groups represented by Rs3 include groups represented by the aforementioned formulas (AL-3) to (AL-5), trialkylsilyl groups in which each alkyl group has 1 to 6 carbon atoms, and alkyl groups containing side oxygen atoms in which each alkyl group has 4 to 20 carbon atoms.

[0661] Rs4 represents (u+1) valence hydrocarbon groups or fluorinated hydrocarbon groups, which can be straight-chain, branched, or cyclic. For specific examples, groups obtained by removing u hydrogen atoms from the aforementioned hydrocarbon groups or fluorinated hydrocarbon groups can be listed.

[0662] Ideally, the fluorinated hydrocarbon group represented by Rsa should be saturated, and it can be linear, branched, or cyclic. Specific examples include those in which some or all of the hydrogen atoms in the aforementioned hydrocarbon group are replaced by fluorine atoms. Specific examples include trifluoromethyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoro-1-propyl, 3,3,3-trifluoro-2-propyl, 2,2,3,3-tetrafluoropropyl, 1,1,1,3,3,3-hexafluoroisopropyl, 2,2,3,3,4,4,4-heptafluorobutyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 2,2,3,3,4,4,5,5,6,6,7,7-dodecylheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, 2-(perfluorodecyl)ethyl, etc.

[0663] Specific examples of repeating units represented by any of the equations (7A) to (7E) can be listed as shown below, but are not limited to these. In addition, RB in the following equations are the same as those mentioned above. [Chemical 509]

[0664] [Chem.510]

[0665] [Chem.511]

[0666] [Chem.512]

[0667] [Chem.513]

[0668] [Chem.514]

[0669] The aforementioned polymeric surfactants may also contain repeating units other than those represented by formulas (7A) to (7E). Examples of such repeating units include those derived from methacrylic acid, α-trifluoromethacrylic acid derivatives, etc. In polymeric surfactants, it is ideal for the content of repeating units represented by formulas (7A) to (7E) to be 20 mol% or more, more ideally 60 mol% or more, and even more ideally 100 mol%.

[0670] For the aforementioned polymeric surfactants, an Mw of 1,000 to 500,000 is more ideal, and an Mw of 3,000 to 100,000 is even more ideal. An Mw / Mn ratio of 1.0 to 2.0 is more ideal, and an Mw / Mn ratio of 1.0 to 1.6 is even more ideal.

[0671] Regarding methods for synthesizing the aforementioned polymeric surfactants, examples include monomers containing unsaturated bonds, provided with repeating units represented by formulas (7A) to (7E) and other repeating units as needed, are polymerized by adding a free radical initiator to an organic solvent and heating. Examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, and dialkylene. Examples of polymerization initiators include AIBN, 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauryl peroxide. A reaction temperature of 50–100°C is ideal. A reaction time of 4–24 hours is ideal. Acid-labile groups can be used directly as introduced into the monomer, or they can be protected or partially protected after polymerization.

[0672] In the synthesis of the aforementioned polymeric surfactants, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can be used to adjust the molecular weight. In this case, the amount of these chain transfer agents added is ideally 0.01 to 10 mol% relative to the total moles of the monomers used for polymerization.

[0673] When the chemical amplification inhibitor composition of this invention includes surfactant (F), its content is ideally 0.1 to 50 parts by mass relative to 80 parts by mass of the base polymer (B), and more ideally 0.5 to 10 parts by mass. If the content of surfactant (F) is 0.1 parts by mass or more, the receding contact angle between the inhibitor film surface and water will be sufficiently improved; if it is less than 50 parts by mass, the dissolution rate of the developer relative to the inhibitor film surface will be low, thus ensuring the height of the formed fine pattern. Surfactant (F) can be used alone or in combination of two or more.

[0674] [(G) Other ingredients] The chemical amplification inhibitor composition of this invention, regarding other components (G), may also contain compounds that decompose due to acid and produce acid (acid amplification compounds), organic acid derivatives, fluorinated alcohols, and compounds with a solubility of Mw3000 or less that change due to acid (dissolution inhibitors). For the aforementioned acid amplification compounds, refer to the compounds described in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608. When containing the aforementioned acid amplification compounds, their content is ideally 0-5 parts by mass relative to 80 parts by mass of the base polymer (B), and more ideally 0-3 parts by mass. If the content is too high, acid diffusion control becomes difficult, potentially leading to degradation of resolution and pattern shape. For the aforementioned organic acid derivatives, fluorinated alcohols and dissolution inhibitors, refer to the compounds described in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608.

[0675] [Pattern Formation Method] The pattern forming method of the present invention includes the following steps: forming a resist film on a substrate using the aforementioned chemical amplification resist composition; exposing the aforementioned resist film to high-energy rays; and developing the aforementioned exposed resist film using a developing solution.

[0676] Regarding the aforementioned substrate, substrates used for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective film, etc.) or substrates used for masking circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) can be used.

[0677] The resist film can be formed by coating the aforementioned chemical amplification resist composition onto a substrate with a film thickness of 0.05 to 2 μm using methods such as spin coating, and then pre-baking it on a heating plate at a temperature of 60 to 150°C for 1 to 10 minutes, or more preferably 80 to 140°C for 1 to 5 minutes.

[0678] Regarding the high-energy rays used in the exposure of resist films, examples 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, a mask used to form the desired pattern can be used, and irradiation can be performed at an exposure dose of 1-200 mJ / cm², or more ideally 10-100 mJ / cm². When using EB, a mask used to form the desired pattern can be used, or irradiation can be performed directly at an exposure dose of 1-300 μC / cm², or more ideally 10-200 μC / cm².

[0679] In addition to the usual exposure method, exposure can also be achieved by immersion, where a liquid with a refractive index of 1.0 or higher is placed between the resist film and the projection lens. In this case, a protective film that is insoluble in water can also be used.

[0680] The aforementioned water-insoluble protective film, used to prevent precipitates from the resist film and improve the hydrophobicity of the film surface, can be broadly categorized into two types. One type is an organic solvent-stripping type, which must be peeled off with an organic solvent that does not dissolve the resist film before alkaline aqueous development. The other type is an alkaline aqueous solution-soluble type, which is soluble in alkaline developing solution and removes the protective film simultaneously with the removal of the soluble portion of the resist film. The latter is particularly ideally based on a polymer containing 1,1,1,3,3,3-hexafluoro-2-propanol residues that are water-insoluble but soluble in alkaline developing solution, and dissolved in alcohol solvents with 4 or more carbon atoms, ether solvents with 8 to 12 carbon atoms, or mixtures thereof. Alternatively, a material can be prepared 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.

[0681] After exposure, PEB can also be performed. PEB can be performed, for example, by heating on a hot plate at a temperature of 60-150°C for 1-5 minutes, or even more ideally at 80-140°C for 1-3 minutes.

[0682] Development is performed using a developer solution containing, for example, 0.1-5% by mass, or more preferably 2-3% by mass, of an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH), and by conventional methods such as dip, immersion, or spraying for 0.1-3 minutes, or more preferably 0.5-2 minutes, thereby dissolving the exposed portion and forming the desired pattern on the substrate.

[0683] 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 after exposure to remove residual water from the film.

[0684] Then, pattern formation can also be achieved using a dual-patterning method. Examples of dual-patterning methods include: a trenching method where a 1:3 trench pattern substrate is processed by first exposure and etching, and then offset, and a 1:3 trench pattern is formed by a second exposure to create a 1:1 pattern; and a line method where a 1:3 isolation pattern first substrate is processed by first exposure and etching, and then offset, and a 1:3 isolation pattern is formed under the first substrate by a second exposure to create a second substrate, thus forming a 1:1 pattern with a pitch of half.

[0685] In the pattern forming method of the present invention, an organic solvent can also be used instead of the aforementioned alkaline aqueous solution as the developing solution to dissolve the unexposed areas in a negative tone development method.

[0686] In the aforementioned organic solvent development, the developer 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, etc. 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 phenyl acetate, ethyl phenyl acetate, benzyl formate, phenyl ethyl formate, methyl 3-phenylpropionate, benzyl propionate, 2-phenylethyl acetate, etc. These organic solvents can be used alone or in combination. [Example]

[0687] The following describes the invention in detail with examples of synthesis, embodiments, and comparative examples, but the invention is not limited to the following embodiments. Furthermore, the apparatus used is as follows. MALDI TOF-MS: S3000 manufactured by Nippon Electronics Co., Ltd.

[0688] [1] Synthesis of onion salts [Example 1-1] Synthesis of onium salt PAG-1 [Chem.515]

[0689] (1) Synthesis of intermediate In-1 Under nitrogen atmosphere, starting materials SM-1 (6.3 g), SM-2 (10.4 g), DMAP (0.3 g), and dichloromethane (50 g) were added to a reaction vessel and cooled in an ice bath. While maintaining the temperature inside the reaction vessel below 20°C, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (5.8 g) was added in powder form. After addition, the temperature was raised to room temperature and allowed to mature for 12 hours. After maturation, water was added to stop the reaction, and a standard aqueous work-up was performed. After distilling off the solvent, diisopropyl ether was added to wash away the residue, thereby obtaining intermediate In-1 20.4 g (92% yield) in oil form.

[0690] (2) Synthesis of PAG-1 Under nitrogen atmosphere, intermediate In-1 (14.4 g), raw material SM-3 (12.6 g), dichloromethane (50 g), and water (30 g) were added. After stirring for 15 minutes, the organic layer was separated, sampled, and washed with water, followed by vacuum concentration. Methyl isobutyl ketone (50 g) was added to the concentrate for azeotropic dehydration, and then diisopropyl ether was added for crystallization, thereby obtaining 20.3 g (94% yield) of the target compound PAG-1 as white crystals.

[0691] MALDI TOF-MS: POSITIVE M+461 (equivalent to C18H10F4IS+) NEGATIVE M-477 (equivalent to C23H13F4O5S-)

[0692] [Examples 1-2~1-9] Synthesis of onium salts PAG-2~PAG-9 Using the corresponding raw materials and known organic synthesis reactions, onium salts PAG-2 to PAG-9 represented by the following formulas were synthesized. [Chem.516]

[0693] [Chem.517]

[0694] [Chem.518]

[0695] [2] Synthesis of basic polymers [Synthetic Example] Synthesis of basic polymers (P-1~P-5) The monomers were combined and copolymerized in MEK solvent. The reaction solution was then added to hexane, and the precipitated solid was washed with hexane, isolated, and dried to obtain the base polymers (P-1 to P-5) with the compositions shown below. The composition of the obtained base polymers was confirmed by 1H-NMR, and Mw and Mw / Mn were confirmed by GPC (solvent: THF, standard: polystyrene). [Chem.519]

[0696] [Chem.520]

[0697] [3] Preparation of chemical amplification inhibitor composition [Examples 2-1 to 2-30, Comparative Examples 1-1 to 1-20] 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), as shown in Tables 1 and 2 below, were dissolved in a solvent containing 0.01% by mass of surfactant A (Omnova Corporation) to prepare a solution. The solution was then filtered through a 0.2 μm Teflon (registered trademark) type filter media to prepare chemical amplification inhibitor compositions (R-1 to R-30 and CR-1 to CR-20).

[0698] [Table 1] inhibitor Composition Basic polymers (parts by weight) Photoacid generator (parts by weight) other Photoacid generator (parts by weight) Quenching agent (parts by weight) Solvent 1 (parts by weight) Solvent 2 (parts by weight) Example 2-1 R-1 P-1(80) PAG-1(28) - Q-1(8.0) PGMEA(2200) DAA(900) Example 2-2 R-2 P-1(80) PAG-2(28) - Q-1(7.8) PGMEA(2200) DAA(900) Example 2-3 R-3 P-1(80) PAG-3(29) - Q-1(7.4) PGMEA(2200) DAA(900) Examples 2-4 R-4 P-1(80) PAG-4(27) - Q-1(8.0) PGMEA(2200) DAA(900) Examples 2-5 R-5 P-1(80) PAG-5(15) PAG-X(10) Q-1(8.0) PGMEA(2200) DAA(900) Examples 2-6 R-6 P-1(80) PAG-6(28) - Q-1(8.0) PGMEA(2200) DAA(900) Examples 2-7 R-7 P-1(80) PAG-7(28) - Q-1(7.8) PGMEA(2200) DAA(900) Examples 2-8 R-8 P-1(80) PAG-8(29) - Q-1(7.4) PGMEA(2200) DAA(900) Examples 2-9 R-9 P-1(80) PAG-9(15) PAG-Y(8) Q-1(8.0) PGMEA(2200) DAA(900) Example 2-10 R-10 P-2(80) PAG-1(29) - Q-1(8.0) PGMEA(2200) DAA(900) Example 2-11 R-11 P-2(80) PAG-2(30) - Q-3(7.8) PGMEA(2200) DAA(900) Example 2-12 R-12 P-2(80) PAG-4(28) - Q-1(8.0) PGMEA(2200) DAA(900) Example 2-13 R-13 P-2(80) PAG-5(18) PAG-Y(7) Q-1(8.0) PGMEA(2200) DAA(900) Example 2-14 R-14 P-2(80) PAG-7(28) - Q-2(4.0) Q-4(4.0) PGMEA(2200) DAA(900) Example 2-15 R-15 P-3(80) PAG-1(10) - Q-1(8.0) PGMEA(2200) DAA(900) Example 2-16 R-16 P-3(80) PAG-2(9) - Q-3(7.6) PGMEA(2200) DAA(900) Example 2-17 R-17 P-3(80) PAG-5(8) PAG-Y(4) Q-1(7.8) PGMEA(2200) DAA(900) Example 2-18 R-18 P-3(80) PAG-7(9) - Q-3 (8.0) PGMEA(2200) DAA(900) Example 2-19 R-19 P-3(80) PAG-9(8) PAG-X(4) Q-2(8.0) PGMEA(2200) DAA(900) Example 2-20 R-20 P-4(80) PAG-1(10) - Q-1(8.0) PGMEA(2200) DAA(900) Example 2-21 R-21 P-4(80) PAG-3(10) - Q-1(7.6) PGMEA(2200) DAA(900) Example 2-22 R-22 P-4(80) PAG-4(8) PAG-X(4) Q-3 (8.0) PGMEA(2200) DAA(900) Example 2-23 R-23 P-4(80) PAG-6(10) - Q-2(8.0) PGMEA(2200) DAA(900) Example 2-24 R-24 P-4(80) PAG-8(8) - Q-3(4.0) Q-4(4.0) PGMEA(2200) DAA(900) Example 2-25 R-25 P-5(80) PAG-1(10) - Q-1(8.0) PGMEA(2200) DAA(900) Example 2-26 R-26 P-5(80) PAG-2(8) - Q-2(8.0) PGMEA(2200) DAA(900) Example 2-27 R-27 P-5(80) PAG-4(8) - Q-3(7.8) PGMEA(2200) DAA(900) Example 2-28 R-28 P-5(80) PAG-6(10) - Q-1(4.0) Q-4(4.0) PGMEA(2200) DAA(900) Example 2-29 R-29 P-5(80) PAG-7(10) - Q-3 (8.0) PGMEA(2200) DAA(900) Examples 2-30 R-30 P-5(80) PAG-9(8) PAG-Y(4) Q-2(7.6) PGMEA(2200) DAA(900)

[0699] [Table 2] inhibitor Composition Basic polymers (parts by weight) Photoacid generator (parts by weight) other Photoacid generator (parts by weight) Quenching agent (parts by weight) Solvent 1 (parts by weight) Solvent 2 (parts by weight) Comparative Example 1-1 CR-1 P-1(80) PAG-A(28) - Q-1(8.0) PGMEA(2200) DAA(900) Comparative Examples 1-2 CR-2 P-1(80) PAG-B(28) - Q-1(7.8) PGMEA(2200) DAA(900) Comparative Examples 1-3 CR-3 P-1(80) PAG-C(29) - Q-1(7.8) PGMEA(2200) DAA(900) Comparative Examples 1-4 CR-4 P-1(80) PAG-D(27) - Q-1(8.2) PGMEA(2200) DAA(900) Comparative Examples 1-5 CR-5 P-1(80) PAG-E(15) PAG-X(10) Q-1(8.2) PGMEA(2200) DAA(900) Comparative Examples 1-6 CR-6 P-2(80) PAG-A(27) - Q-2(8.0) PGMEA(2200) DAA(900) Comparative Examples 1-7 CR-7 P-2(80) PAG-B(25) - Q-1(8.0) PGMEA(2200) DAA(900) Comparative Examples 1-8 CR-8 P-2(80) PAG-E(18) PAG-Y(7) Q-1(8.0) PGMEA(2200) DAA(900) Comparative Examples 1-9 CR-9 P-3(80) PAG-A(10) - Q-1(7.8) PGMEA(2200) DAA(900) Comparative Examples 1-10 CR-10 P-3(80) PAG-B(9) - Q-3 (8.0) PGMEA(2200) DAA(900) Comparative Examples 1-11 CR-11 P-3(80) PAG-C(10) - Q-1(4.0) Q-4(4.0) PGMEA(2200) DAA(900) Comparative Examples 1-12 CR-12 P-3(80) PAG-D(8) - Q-2(7.6) PGMEA(2200) DAA(900) Comparative Examples 1-13 CR-13 P-4(80) PAG-A(10) - Q-1(7.8) PGMEA(2200) DAA(900) Comparative Examples 1-14 CR-14 P-4(80) PAG-B(10) - Q-2(8.0) PGMEA(2200) DAA(900) Comparative Examples 1-15 CR-15 P-4(80) PAG-C(10) - Q-3(4.0) Q-4(4.0) PGMEA(2200) DAA(900) Comparative Examples 1-16 CR-16 P-4(80) PAG-E(8) PAG-X(4) Q-1(8.0) PGMEA(2200) DAA(900) Comparative Examples 1-17 CR-17 P-5(80) PAG-A(10) - Q-1(8.0) PGMEA(2200) DAA(900) Comparative Examples 1-18 CR-18 P-5(80) PAG-B(10) - Q-3(7.6) PGMEA(2200) DAA(900) Comparative Examples 1-19 CR-19 P-5(80) PAG-C(8) - Q-1(4.0) Q-4(4.0) PGMEA(2200) DAA(900) Comparative Examples 1-20 CR-20 P-5(80) PAG-E(8) PAG-Y(4) Q-2(8.0) PGMEA(2200) DAA(900)

[0700] 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 as follows. Solvent: PGMEA (Propylene Glycol Monomethyl Ether Acetate) DAA (diacetone alcohol)

[0701] Other photoacid generators: PAG-X, PAG-Y [Chem.521]

[0702] • Comparison of photoacid generating agents: PAG-A~PAG-E [Chem.522]

[0703] Quenching agents: Q-1~Q-4 [Chem.523]

[0704] Surfactant A: 3-methyl-3-(2,2,2-trifluoroethoxymethyl)oxetane-tetrahydrofuran-2,2-dimethyl-1,3-propanediol copolymer (manufactured by Omnova). [Chem.524] a:(b+b'):(c+c')=1:4~7:0.01~1 (Morbies) Mw=1500

[0705] [4] Evaluation of EUV lithography (1) [Examples 3-1 to 3-30, Comparative Examples 2-1 to 2-20] The chemical amplification resist compositions (R-1~R-30, CR-1~CR-20) shown in Tables 1 and 2 were spin-coated onto a Si substrate with a silicon spin-coated hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd., with a film thickness of 20 nm. The substrate was pre-baked at 100°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. The resist film was then exposed to an LS pattern with a wafer size of 18 nm and a pitch of 36 nm using an ASML EUV scanning lithography machine NXE3400 (NA 0.33, σ 0.9 / 0.6, dipole illumination) while varying the exposure amount and focal length (exposure pitch: 1 mJ / cm2, focal point pitch: 0.020 μm). After exposure, a PEB was performed at the temperatures shown in Tables 3 and 4 for 60 seconds. Subsequently, the sample was immersed in a 2.38% TMAH aqueous solution for 30 seconds for development, rinsed with a rinsing material containing surfactants, and then vortexed to obtain a positive pattern. The obtained LS patterns were observed using a Hitachi Advanced CD-SEM (CG6300), and the sensitivity, EL, LWR, depth of focus (DOF), and collapse limit were evaluated using the following methods. The results are shown in Tables 3 and 4.

[0706] [Sensitivity Evaluation] The optimal exposure value Eop (mJ / cm2) for obtaining an LS pattern with a linewidth of 18nm and a pitch of 36nm is determined and used as the sensitivity. The smaller the value, the higher the sensitivity.

[0707] [EL Review] Based on the exposure amount formed within ±10% (16.2~19.8nm) of the 18nm interval width in the aforementioned LS pattern, the EL (unit: %) is calculated using the following formula. The larger this value, the better the performance. EL(%) = (|E1-E2| / Eop) × 100 E1: Provides optimal exposure for LS patterns with a linewidth of 16.2nm and a pitch of 36nm. E2: Provides optimal exposure for LS patterns with a linewidth of 19.8nm and a pitch of 36nm. Eop: Provides optimal exposure for LS patterns with a linewidth of 18nm and a pitch of 36nm.

[0708] [LWR Evaluation] For the LS pattern obtained by Eop irradiation, the dimensions at 10 points along the long side of the line are measured, and the standard deviation (σ) is calculated as 3 times the value (3σ) as the LWR. The smaller the value, the smaller the roughness, and a pattern with uniform line width can be obtained.

[0709] [DOF Rating] In terms of depth of focus evaluation, the focal length range formed within ±10% (16.2~19.8nm) of the 18nm size in the aforementioned LS pattern is determined. The larger the value, the wider the depth of focus.

[0710] [Collapse Limit Assessment of Line Patterns] The line dimensions of each exposure at the optimal focal length for 10 of the aforementioned LS patterns were measured along the long side. The finest line dimension that could be obtained without collapse was taken as the collapse limit dimension. The smaller the value, the better the collapse limit.

[0711] [Table 3] inhibitor Composition PEB temperature (°C) Optimal exposure (mJ / cm2) EL (%) LWR (nm) DOF (nm) Collapse Limit (nm) Example 3-1 R-1 100 33 19 2.4 120 10.5 Example 3-2 R-2 100 34 18 2.5 120 10.7 Example 3-3 R-3 95 34 17 2.5 120 10.6 Examples 3-4 R-4 105 33 17 2.6 110 10.6 Examples 3-5 R-5 105 34 18 2.5 100 10.5 Examples 3-6 R-6 95 35 19 2.6 110 11.3 Examples 3-7 R-7 105 34 17 2.5 120 11.1 Examples 3-8 R-8 105 35 18 2.6 120 11.2 Examples 3-9 R-9 100 34 18 2.5 120 10.7 Examples 3-10 R-10 95 35 17 2.7 120 10.9 Example 3-11 R-11 100 35 18 2.6 100 10.7 Example 3-12 R-12 105 34 19 2.6 110 11.4 Example 3-13 R-13 105 36 18 2.5 110 10.7 Example 3-14 R-14 100 34 19 2.6 110 11.4 Example 3-15 R-15 100 33 18 2.4 120 10.9 Example 3-16 R-16 100 34 17 2.5 120 10.7 Example 3-17 R-17 105 35 18 2.6 110 11.4 Example 3-18 R-18 95 34 18 2.5 120 10.9 Example 3-19 R-19 100 35 17 2.5 110 10.8 Example 3-20 R-20 105 35 18 2.7 100 11.5 Example 3-21 R-21 95 34 17 2.5 120 11.1 Example 3-22 R-22 100 36 19 2.4 110 10.9 Example 3-23 R-23 105 35 18 2.5 120 11.2 Example 3-24 R-24 95 34 18 2.6 120 11.2 Example 3-25 R-25 100 35 18 2.5 110 10.7 Example 3-26 R-26 95 34 19 2.5 120 10.9 Example 3-27 R-27 100 35 18 2.6 100 10.9 Example 3-28 R-28 100 34 17 2.5 120 11.0 Example 3-29 R-29 100 35 17 2.6 110 11.3 Examples 3-30 R-30 95 34 19 2.5 110 11.1

[0712] [Table 4] inhibitor Composition PEB temperature (°C) Optimal exposure (mJ / cm2) EL (%) LWR (nm) DOF (nm) Collapse Limit (nm) Comparative Example 2-1 CR-1 100 38 14 3.1 80 11.9 Comparative Example 2-2 CR-2 100 39 14 3.5 90 12.3 Comparative Examples 2-3 CR-3 105 41 15 3.0 100 12.2 Comparative Examples 2-4 CR-4 100 43 15 3.2 80 12.4 Comparative Examples 2-5 CR-5 100 42 14 3.1 70 12.1 Comparative Examples 2-6 CR-6 100 38 13 3.3 80 12.3 Comparative Examples 2-7 CR-7 100 39 15 3.1 90 12.2 Comparative Examples 2-8 CR-8 105 38 14 3.3 80 12.5 Comparative Examples 2-9 CR-9 100 42 13 3.0 100 12.3 Comparative Example 2-10 CR-10 100 43 13 3.1 90 12.2 Comparative Example 2-11 CR-11 95 41 14 3.2 80 12.4 Comparative Example 2-12 CR-12 100 39 15 3.4 80 12.1 Comparative Example 2-13 CR-13 100 40 16 3.0 70 12.0 Comparative Example 2-14 CR-14 100 39 15 2.9 90 11.8 Comparative Example 2-15 CR-15 100 42 14 3.3 80 12.3 Comparative Example 2-16 CR-16 95 41 15 3.1 90 11.8 Comparative Example 2-17 CR-17 100 39 13 3.4 80 12.4 Comparative Example 2-18 CR-18 105 38 15 3.1 80 11.9 Comparative Example 2-19 CR-19 100 38 14 3.3 90 11.7 Comparative Example 2-20 CR-20 100 40 15 3.2 80 12.4

[0713] Based on the results shown in Tables 3 and 4, it can be understood that the chemical amplification inhibitor 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 was confirmed that the collapse limit value is small, and the pattern's resistance to collapse is also strong during the formation of fine patterns. Therefore, it is shown that the chemical amplification inhibitor composition of the present invention is ideal as a material for EUV lithography.

[0714] [5] Evaluation of EUV lithography (2) [Examples 4-1 to 4-30, Comparative Examples 3-1 to 3-20] The chemical amplification resist compositions (R-1~R-30, CR-1~CR-20) shown in Tables 1 and 2 were spin-coated onto a Si substrate with a silicon spin-coating hard mask SHB-A940 (silicon content 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 create a resist film with a thickness of 50 nm. The resist film was then exposed using an ASML NXE3400 EUV scanning exposure machine (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask with a wafer-sized hole pattern of 46 nm pitch and +20% deviation). The substrate was then subjected to PEB treatment at the temperatures recorded in Tables 5 and 6 for 60 seconds 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. Using a Hitachi Advanced CD-SEM (CG6300), the exposure was measured when the aperture size was 23 nm, and this was used as the sensitivity. Furthermore, the size of 50 apertures at this time was measured, and three times the standard deviation (σ) calculated from the results (3σ) was taken as the CDU. The results are shown in Tables 5 and 6.

[0715] [Table 5] inhibitor composition PEB temperature (°C) Optimal exposure (mJ / cm2) CDU (nm) Example 4-1 R-1 95 twenty two 2.2 Example 4-2 R-2 95 twenty three 2.3 Example 4-3 R-3 95 twenty four 2.4 Example 4-4 R-4 90 twenty four 2.3 Examples 4-5 R-5 90 twenty two 2.5 Examples 4-6 R-6 95 25 2.4 Examples 4-7 R-7 90 twenty four 2.5 Examples 4-8 R-8 95 twenty four 2.2 Examples 4-9 R-9 90 twenty three 2.3 Examples 4-10 R-10 95 25 2.5 Example 4-11 R-11 90 25 2.3 Example 4-12 R-12 90 twenty four 2.3 Example 4-13 R-13 95 twenty four 2.5 Example 4-14 R-14 95 twenty three 2.5 Examples 4-15 R-15 95 twenty three 2.6 Example 4-16 R-16 95 25 2.4 Example 4-17 R-17 90 twenty two 2.4 Example 4-18 R-18 90 twenty four 2.3 Example 4-19 R-19 95 twenty four 2.3 Example 4-20 R-20 90 twenty three 2.4 Example 4-21 R-21 95 twenty four 2.6 Example 4-22 R-22 90 25 2.4 Example 4-23 R-23 95 twenty three 2.3 Example 4-24 R-24 90 twenty three 2.5 Example 4-25 R-25 95 twenty two 2.4 Example 4-26 R-26 90 25 2.4 Example 4-27 R-27 95 twenty four 2.5 Example 4-28 R-28 90 25 2.2 Example 4-29 R-29 90 25 2.4 Example 4-30 R-30 95 twenty four 2.6

[0716] [Table 6] inhibitor composition PEB temperature (°C) Optimal exposure (mJ / cm2) CDU (nm) Comparative Example 3-1 CR-1 90 27 2.9 Comparative Example 3-2 CR-2 90 28 2.7 Comparative Example 3-3 CR-3 85 27 2.8 Comparative Examples 3-4 CR-4 90 28 2.9 Comparative Examples 3-5 CR-5 95 29 3.3 Comparative Examples 3-6 CR-6 90 29 3.1 Comparative Examples 3-7 CR-7 85 28 2.8 Comparative Examples 3-8 CR-8 90 29 3.1 Comparative Examples 3-9 CR-9 90 28 2.8 Comparative Example 3-10 CR-10 90 29 2.8 Comparative Example 3-11 CR-11 85 30 3.2 Comparative Example 3-12 CR-12 90 29 3.3 Comparative Example 3-13 CR-13 90 31 3.0 Comparative Example 3-14 CR-14 90 32 3.1 Comparative Example 3-15 CR-15 90 28 2.9 Comparative Example 3-16 CR-16 85 28 2.8 Comparative Example 3-17 CR-17 95 29 2.9 Comparative Example 3-18 CR-18 90 28 2.8 Comparative Example 3-19 CR-19 90 29 2.8 Comparative Example 3-20 CR-20 90 30 3.0

[0717] Based on the results shown in Tables 5 and 6, it was confirmed that the chemical amplification inhibitor composition containing the photoacid generator composed of the onium salt of the present invention has good sensitivity and excellent CDU.

Claims

1. An onium salt, comprising an anion represented by formula (1A) and a cation represented by formula (1B); wherein n1 is 0 or 1; n2 is an integer from 0 to 4; n3 is an integer from 0 to 4; but when n1 is 0, 0 ≤ n2 + n3 ≤ 4, and when n1 is 1, 0 ≤ n2 + n3 ≤ 6; n4 is 1; W is represented by formula (W-2); wherein n8 is 0 or 1; n9 is 0 or 1; n10 is an integer from 0 to 4; n11 is an integer from 0 to 4; R3 and R4 are each independently hydrogen atoms, halogen atoms, or may contain heteroatoms of 1 to 20 carbon atoms in a hydrocarbon group; R5 to R9 are each independently hydrogen atoms, halogen atoms, or may contain heteroatoms of 1 to 40 carbon atoms in a hydrocarbon group; the dashed lines represent atomic bonds with LA1; RF1 is a fluorine atom, a fluorinated saturated hydrocarbon group with 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group with 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group with 1 to 6 carbon atoms; R1 is a halogen atom other than fluorine, a nitro 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 n3 is 2, 3, or 4, each R1 can be the same or different, and multiple R1s can also bond to each other and form a ring together with the carbon atoms they are bonded to; LA1 and LB1 are each independently a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond; XL1 is a single bond, or may contain a hydrocarbon group with 1 to 40 carbon atoms containing heteroatoms; In the formula, m1 is 0 or 1; m2 is 0 or 1; m3 is 0 or 1; m4 is an integer from 0 to 4; m5 is an integer from 0 to 4; m6 is an integer from 0 to 6; m7 is an integer from 0 to 6; m8 is an integer from 0 to 2; m9 is an integer from 0 to 2; m10 is an integer from 0 to 2; m11 is 0 or 1; m12 is an integer from 0 to 4; m13 is an integer from 0 to 2; m14 is an integer from 0 to 2; but when m1 is 0, 0 ≤ m6 + m 9≦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; Each of RF2 to RF4 is independently a fluorine atom, a fluorinated saturated hydrocarbon group with 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group with 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group with 1 to 6 carbon atoms; when m5 is 2 or more, each RF2 can be the same or different from each other; when m6 is 2 or more, each RF3 can be the same or different from each other; when m7 is 2 or more, each RF4 can be the same or different from each other.R11~R14 can be halogen atoms other than iodine and fluorine atoms, nitro, cyano, or hydrocarbon groups with 1~20 carbon atoms containing heteroatoms, hydrocarbon oxygen groups with 1~20 carbon atoms containing heteroatoms, or hydrocarbon thio groups with 1~20 carbon atoms containing heteroatoms; when m8 is 2, the two R11s can be the same or different, and the two R11s can also bond to each other and form a ring together with the carbon atoms they bond to; when m9 is 2, the two R12s can be the same or different, and the two R12s can also bond to each other and form a ring together with the carbon atoms they bond to; when m10 is 2, the two R13s can be the same or different, and the two R13s can also bond to each other and form a ring together with the carbon atoms they bond to; when m13 is 2, the two R14s can be the same or different, and the two R14s can also bond to each other and form a ring together with the carbon atoms they bond to; Furthermore, the aromatic rings of S+ directly bonded to the strontium cation can also bond with each other to form rings together with S+; LA2 and LB2 are each independently a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond; XL2 is a single bond, or may also contain a heteroatom with 1 to 40 carbon atoms.

2. As in request item 1, the onium salt, where, The anion is represented by the following formula (1A-1); where n1~n4, W, RF1, R1 and LA1 are the same as those mentioned above.

3. As in request item 1, the onium salt, where, The cation is represented by the following formula (1B-1); in which m4~m10, m12~m14, RF2~RF4, R11~R14, LA2, LB2 and XL2 are the same as those mentioned above.

4. As in request item 3, the onium salt, wherein, The cation is represented by the following formula (1B-2); in which m4~m10, RF2~RF4 and R11~R13 are the same as those mentioned above.

5. A photoacid generator comprising a bellium salt of any one of claims 1 to 4.

6. A chemical amplification inhibitor composition comprising the photoacid generator as claimed in claim 5.

7. The chemical amplification inhibitor composition of claim 6 further comprises a base polymer containing repeating units represented by formula (a1) or (a2); wherein RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; X1 is a single bond, phenyl, naphthyl, or *-C(=O)-O-X11-, which may also be substituted with hydroxyl, nitro, cyano, a saturated hydrocarbon group containing 1 to 10 carbon atoms with fluorine atoms, or a saturated hydrocarbon oxygen group containing 1 to 10 carbon atoms with fluorine atoms or a halogen atom; X11 is a saturated hydrocarbon group containing 1 to 10 carbon atoms, phenyl, or naphthyl, which may also contain hydroxyl, ether bond, ester bond, or lactone ring; X2 is a single bond or *-C(=O)-O-; * indicates an atomic bond with a carbon atom of the main chain; R21 can be a halogen atom, cyano, hydroxyl, nitro, or may contain a hydrocarbon group with 1 to 20 carbon atoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms, a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms; AL1 and AL2 are each independently acid-labile groups; a is an integer from 0 to 4.

8. The chemical amplification inhibitor composition as claimed in claim 7, wherein, The basic polymer contains repeating units represented by the following formula (a3); where b1 is 0 or 1; b2 is an integer from 0 to 3 when b1 is 0, and an integer from 0 to 5 when b1 is 1; RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; X3 is a single bond, *-C(=O)-O- or *-C(=O)-NH-; * indicates an atomic bond with a carbon atom of the main chain; X4 is a single bond, an aliphatic hydrocarbon group with 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining them; X5 and X6 are each independently an oxygen atom or a sulfur atom; however, X4 and X6 are carbon atoms bonded to adjacent aromatic rings; R22 and R23 are each independently a hydrogen atom, or may also contain hydrocarbon groups with 1 to 20 carbon atoms containing heteroatoms; furthermore, R22 and R23 may also bond to each other and form a ring together with the carbon atoms they bond to; R24 can be a halogen atom, hydroxyl group, cyano group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms containing heteroatoms, or -N(R24A)(R24B); R24A and R24B are each independently a hydrogen atom or a hydrocarbon group with 1 to 6 carbon atoms; when b2 is 2 or more, the multiple R24s can also bond to each other and form a ring together with the carbon atoms of the aromatic rings they are bonded to.

9. The chemical amplification inhibitor composition as claimed in claim 7, wherein, The basic polymer contains repeating units represented by formula (b1) or (b2); where RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Y1 is a single bond or *-C(=O)-O-; * represents an atomic bond with a carbon atom of the main chain; R31 is a hydrogen atom, or a group with 1 to 20 carbon atoms containing at least one of the following: 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)-); R32 can be a halogen atom, hydroxyl group, carboxyl group, nitro group, cyano group, or a hydrocarbon group with 1 to 20 carbon atoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms; b is an integer from 1 to 4; c is an integer from 0 to 4; but 1 ≤ b + c ≤ 5.

10. The chemical amplification inhibitor composition as claimed in claim 7, wherein, The basic polymer comprises 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); wherein d1 and d2 are each independently 0, 1, 2, or 3; e1 is 0 or 1; e2 is an integer from 0 to 4; e3 is an integer from 0 to 4; but when e1 is 0, 0 ≤ e2 + e3 ≤ 4, and when e1 is 1, 0 ≤ e2 + e3 ≤ 6; RA are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Z1 is a single bond or may also have substituents, such as a phenyl group; Z2 is a single bond, **-C(=O)-O-Z21-, **-C(=O)-NH-Z21-, or **-O-Z21-; Z21 is an aliphatic alkyl group, phenyl group, or a divalent group obtained by combining them with 1 to 6 carbon atoms, and may also contain a halogen atom, carbonyl group, ester bond, ether bond, or hydroxyl group; Z3 is a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond; Z4 is a single bond, or an aliphatic alkyl group, phenyl group, or a divalent group obtained by combining them with 1 to 6 carbon atoms, and may also contain a halogen atom, carbonyl group, ester bond, ether bond, or hydroxyl group; Z5 is independently a single bond, or may contain substituents such as phenyl, naphthyl, or *-C(=O)-O-Z51-; Z51 is an aliphatic alkyl group, phenyl, or naphthyl with 1 to 10 carbon atoms, which may also contain halogen atoms, hydroxyl groups, ether bonds, ester bonds, or lactone rings; Z6 is a single bond, ether bond, ester bond, sulfonate bond, amide bond, sulfonamide bond, carbonate bond, or carbamate bond; Z7 is independently a single bond, ***-Z71-C(=O)-O-, ***-C(=O)-NH-Z71-, or ***-O-Z71-; Z71 may also contain heteroatoms and is an alkyl group with 1 to 20 carbon atoms; Z8 can be a single bond, ****-Z81-C(=O)-O-, ****-C(=O)-NH-Z81-, or ****-O-Z81-; Z81 can be a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms; Z9 can be a single bond, methylene, ethyl, phenyl, fluorinated phenyl, trifluoromethyl-substituted phenyl, *-C(=O)-O-Z91-, *-C(=O)-N(H)-Z91-, or *-O-Z91-; Z91 can be an aliphatic hydrocarbon group with 1 to 6 carbon atoms, phenyl, fluorinated phenyl, or trifluoromethyl-substituted phenyl, which may also contain carbonyl, ester, ether, or hydroxyl groups; * indicates an atomic bond with a carbon atom in the main chain; ** indicates an atomic bond with Z1; *** indicates an atomic bond with Z6; **** indicates an atomic bond with Z7; L1 can be a single bond, ether bond, ester bond, carbonyl group, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond; Rf1 and Rf2 can each be independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms;Rf3 and Rf4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Rf5 and Rf6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; however, Rf5 and Rf6 are not all simultaneously hydrogen atoms; Rf7 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 alkyl thio group having 1 to 6 carbon atoms; R41 and R42 are each independently a hydrocarbon group having 1 to 20 carbon atoms, which may also contain heteroatoms; furthermore, R41 and R42 may also bond to each other and form a ring together with the sulfur atoms they are bonded to; R43 is a halogen atom other than a fluorine atom, or a hydrocarbon group having 1 to 20 carbon atoms, which may also contain heteroatoms; when e3 is 2, 3, or 4, multiple R43s may also bond to each other and form a ring together with the carbon atoms they are bonded to; M- is a non-nucleophilic relative ion; A+ is an onium cation. ; 11. The chemical amplification inhibitor composition as described in claim 6 further includes an organic solvent.

12. The chemical amplification inhibitor composition of claim 6 further includes a quencher.

13. The chemical amplification inhibitor composition of claim 6 further includes photoacid generating agents other than the photoacid generating agent of claim 5.

14. The chemical amplification inhibitor composition of claim 6 further includes a surfactant.

15. A pattern forming method comprising the following steps: forming a resist film on a substrate using a chemical amplifying resist composition as claimed in claim 6; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developing solution.

16. The pattern forming method as described in claim 15, wherein, This high-energy ray system includes KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light with wavelengths of 3-15 nm.