Onium salt, photoacid generator, polymer, resist composition, and method for producing device using the resist composition

Abstract

To provide a compound suitably used as a photoacid generator in a resist composition with high sensitivity to active energy such as EB and EUV, excellent lithographic resolution, and the capability to reduce LWR in fine patterns, and to provide a resist composition formed using the compound.SOLUTION: The compound suitably used as a photoacid generator is an onium salt, and specifically, for example, the following compound A-2 is illustrated.SELECTED DRAWING: None

Description

[Technical field]

[0001] One aspect of the present invention relates to a photoacid generator, more specifically to a photoacid generator suitable for use in a resist composition for lithography. Some aspects of the present invention also relate to a resist composition containing the photoacid generator, and a method for manufacturing a device using the resist composition. [Background technology]

[0002] In recent years, photolithography technology using photoresists has been actively used to manufacture display devices such as liquid crystal displays (LCDs) and organic light-emitting diode displays (OLEDs), as well as to form semiconductor elements. For the packaging of the above electronic components and products, active energy rays such as i-rays with a wavelength of 365 nm, and longer wavelengths such as h-rays (405 nm) and g-rays (436 nm) are widely used.

[0003] As the integration of devices becomes more advanced, there is an increasing demand for finer lithography technology, and there is a tendency for high-energy rays such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), extreme ultraviolet light (hereinafter also referred to as "EUV", wavelength 13.5 nm), and electron beam (hereinafter also referred to as "EB") to be used for exposure. Lithography techniques using these short-wavelength lights, particularly electron beam (EB) or extreme ultraviolet light (EUV), enable production with single patterning, so it is believed that the need for resist compositions that exhibit high sensitivity to electron beam (EB) or extreme ultraviolet light (EUV) will further increase in the future.

[0004] As exposure light sources become shorter in wavelength, resist compositions are required to have improved properties such as high sensitivity to the exposure light source and the reproducibility of fine dimensional patterns. A chemically amplified resist using a photoacid generator is known as a resist composition that satisfies such requirements (Patent Document 1). However, with the rapid miniaturization, in chemically amplified resists using photoacid generators, the acid generated by exposure diffuses in the resist film, which has a significant effect on lithography performance and reduces the contrast and line width roughness (LWR) characteristics of the line pattern. Onium salts with bulky anionic structures have been proposed for the purpose of appropriately controlling the diffusion of the acid generated from the photoacid generator (Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 6-287174 [Patent Document 2] JP 2018-92159 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the current situation where the miniaturization of resist patterns has progressed to a level of line width of 40 nm or less, there is a demand for resist compositions that exhibit pattern performance such as sensitivity and LWR. However, it is difficult for conventional chemically amplified resist compositions to simultaneously satisfy the characteristics of pattern performance such as sensitivity to electron beam (EB) or extreme ultraviolet (EUV) and line width roughness (LWR). It is considered that general photoacid generators have problems in terms of sensitivity to electron beam (EB) or extreme ultraviolet (EUV) and LWR.

[0007] An object of one aspect of the present invention is to provide an onium salt for use in a resist composition that is excellent in pattern performance characteristics such as sensitivity to electron beam (EB) or extreme ultraviolet (EUV) radiation, and LWR. Another object of one embodiment of the present invention is to provide a photoacid generator containing the above-described onium salt, a resist composition containing the photoacid generator, and a method for manufacturing a device using the resist composition. [Means for solving the problem]

[0008] As a result of intensive investigations aimed at solving the above-mentioned problems, the present inventors have found that by incorporating an onium salt having a specific structure in formula (1) below as a photoacid generator in a resist composition, it is possible to improve pattern performance characteristics against electron beams (EB), extreme ultraviolet rays (EUV), and the like, and have completed several aspects of the present invention.

[0009] That is, one embodiment of the present invention is an onium salt represented by the following formula (1).

[0010] [ka]

[0011] In the above formula (1), A - is a sulfonate or carboxylate anion. Q is any one selected from the group consisting of a hydrogen atom; a fluorine atom; and a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms which may have a substituent. r is an integer from 0 to 4. The multiple Q's may be the same or different. T is at least one selected from the group consisting of a single bond; a linear, branched or cyclic alkylene group having 1 to 30 carbon atoms which may have a substituent; a linear, branched or cyclic alkenylene group having 2 to 30 carbon atoms which may have a substituent; an arylene group having 5 to 30 carbon atoms which may have a substituent; and a heteroarylene group having 3 to 30 carbon atoms which may have a substituent. At least one methylene group in the above T may be substituted with a divalent heteroatom-containing group. L is a single bond or a divalent heteroatom-containing group. Z is a group represented by the following formula (2), and bonds to the above L in place of at least one hydrogen atom in the formula (2). M + is a monovalent onium cation.

[0012] [ka]

[0013] In the above formula (2), G is -CO- or -S(O)2-. R 1 ~R 3 is any one selected from the group consisting of a hydrogen atom; a halogen atom; a hydroxy group; a mercapto group; a carboxyl group; a sulfonate group; a phosphate group; an optionally substituted diaryl phosphate group having 5 to 30 carbon atoms; an optionally substituted dialkyl phosphate group having 1 to 30 carbon atoms; an optionally substituted alkylaryl phosphate group having 6 to 30 carbon atoms; an optionally substituted amino group; an optionally substituted linear, branched or cyclic alkyl group having 1 to 30 carbon atoms; an optionally substituted linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms; an optionally substituted aryl group having 5 to 30 carbon atoms; and an optionally substituted heteroaryl group having 3 to 30 carbon atoms. Above R 1 ~R 3 When there are two or more, R 1 ~R 3 two of them may be bonded to each other directly via a single bond or via at least one selected from the group consisting of a divalent heteroatom-containing group and a linear, branched or cyclic alkylene group having 1 to 30 carbon atoms which may have a substituent to form a ring structure. The aromatic ring and R in the above formula (2) 1 ~R 3 may be bonded via a divalent heteroatom-containing group. The two aromatic rings in the above formula (2) may form a ring with the quaternary carbon via a single bond or a divalent heteroatom-containing group. Above R 1 ~R 3 When there are two or more, multiple R 1 ~R 3 may be the same or different. Above R 1 ~R 3 At least one methylene group therein may be substituted with a divalent heteroatom-containing group. "l" is an integer of 0 to 4; "m" is an integer of 0 to 5; and "n" is an integer of 0 to 5.

[0014] Further, another aspect of the present invention is a photoacid generator containing the above-mentioned onium salt, a polymer containing the above-mentioned onium salt as a repeating unit, and a resist composition containing the photoacid generator or the polymer. In another embodiment of the present invention, the resist composition further contains an acid-reactive compound.

[0015] In another aspect of the present invention, the acid-reactive compound is at least one selected from the group consisting of a compound having a protecting group that is deprotected by an acid, a compound having a polymerizable group that is polymerized by an acid, and a crosslinking agent that has a crosslinking action by an acid.

[0016] Furthermore, another aspect of the present invention is a method for manufacturing a device, comprising the steps of forming a resist film on a substrate using the resist composition, exposing the resist film to active energy rays, and developing the exposed resist film.

[0017] Various aspects of the present invention are exemplified below. Each of the following aspects is mutually applicable to the other aspects. [1] An onium salt represented by the following formula (1): [ka] (In the above formula (1), A - is a sulfonate or carboxylate anion, Q is any one selected from the group consisting of a hydrogen atom; a fluorine atom; and a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms which may have a substituent; r is an integer from 0 to 4; Multiple Q's may be the same or different, T is at least one selected from the group consisting of a single bond; a linear, branched or cyclic alkylene group having 1 to 30 carbon atoms which may have a substituent; a linear, branched or cyclic alkenylene group having 2 to 30 carbon atoms which may have a substituent; an arylene group having 5 to 30 carbon atoms which may have a substituent; and a heteroarylene group having 3 to 30 carbon atoms which may have a substituent; At least one methylene group in T may be substituted with a divalent heteroatom-containing group; L is a single bond or a divalent heteroatom-containing group; Z is a group represented by the following formula (2), which is bonded to L in place of at least one hydrogen atom in the formula (2): M + is a monovalent onium cation. [ka] (In the formula (2), G is -CO- or -S(O)2-, R 1 ~R 3 is any one selected from the group consisting of a hydrogen atom; a halogen atom; a hydroxy group; a mercapto group; a carboxyl group; a sulfonate group; a phosphate group; an optionally substituted diaryl phosphate group having 5 to 30 carbon atoms; an optionally substituted dialkyl phosphate group having 1 to 30 carbon atoms; an optionally substituted alkylaryl phosphate group having 6 to 30 carbon atoms; an optionally substituted amino group; an optionally substituted linear, branched or cyclic alkyl group having 1 to 30 carbon atoms; an optionally substituted linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms; an optionally substituted aryl group having 5 to 30 carbon atoms; and an optionally substituted heteroaryl group having 3 to 30 carbon atoms; R 1 ~R 3 When there are two or more, R 1 ~R 3two of the may be bonded to each other directly via a single bond or via at least one selected from the group consisting of a divalent heteroatom-containing group and a linear, branched or cyclic alkylene group having 1 to 30 carbon atoms which may have a substituent to form a ring structure, The aromatic ring and R in the formula (2) 1 ~R 3 may be bonded via a divalent heteroatom-containing group, The two aromatic rings in the formula (2) may form a ring with a quaternary carbon via a single bond or a divalent heteroatom-containing group, R 1 ~R 3 When there are two or more, multiple R 1 ~R 3 may be the same or different, R 1 ~R 3 at least one methylene group may be substituted with a divalent heteroatom-containing group; "l" is an integer of 0 to 4; "m" is an integer of 0 to 5; and "n" is an integer of 0 to 5. [2] The onium salt according to [1], wherein L is any one selected from the group consisting of -O-, -CO-, -COO-, -OCO-, -O-CO-O-, -NHCO-, -CONH-, -NH-CO-O-, -O-CO-NH-, -O-CO-CH2-CO-O-, -CO-CO-O-, -CH2-O-CO-, -CH2-O-, -CH2-O-CO-O-, -S-, -SO-, -S(O)2-, and -CO-O-CH2-CO-O-. [3] R in the above formula (2) 1 ~R 3 3. The onium salt according to claim 1, wherein at least one of the following is an iodine atom: [4] Said M + is a sulfonium cation or an iodonium cation. [5] A photoacid generator comprising the onium salt according to any one of [1] to [4]. [6] A polymer comprising a repeating unit having the onium salt according to any one of [1] to [5]. [7] A resist composition comprising the photoacid generator according to [5] or the polymer according to [6]. [8] The resist composition according to [7], further comprising an acid-reactive compound. [9] The resist composition according to [8], wherein the acid-reactive compound is at least one selected from the group consisting of a compound having a protecting group that can be deprotected by an acid, a compound having a polymerizable group that can be polymerized by an acid, and a crosslinking agent that has a crosslinking action when exposed to an acid.

[10] The resist composition according to any one of [7] to [9], further comprising an acid diffusion controller.

[11] The resist composition according to any one of [7] to

[10] , further comprising a water-repellent compound.

[12] forming a resist film on a substrate using the resist composition according to any one of [7] to

[11] ; exposing the resist film to active energy rays; and developing the exposed resist film.

[13] The method for manufacturing a device according to

[12] , wherein the active energy rays are extreme ultraviolet rays or electron beams. Effect of the Invention

[0018] The photoacid generator according to one embodiment of the present invention contains an onium salt having a specific anion structure, and thus has excellent sensitivity and patterning performance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Several aspects of the present invention will now be described. <1> Onium salts One aspect of the invention features onium salts having a particular structure. Several aspects of the present invention will be specifically described below, but the present invention is not limited thereto.

[0020] <1-1> Anion of onium salt The anion of the onium salt in one embodiment of the present invention is represented by the above formula (1). A - is a sulfonate or carboxylate anion.

[0021] Q represents a hydrogen atom; a fluorine atom; or a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms which may have a substituent.

[0022] Examples of the linear alkyl group having 1 to 30 carbon atoms, which may have a substituent, as Q include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-dodecyl group, a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexyl group, and other perfluoroalkyl groups.

[0023] Examples of the branched alkyl group having 1 to 30 carbon atoms which may have a substituent as Q include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a tert-pentyl group, a 2-ethyloctyl group, and a 2-ethyldecyl group.

[0024] Examples of the cyclic alkyl group having 1 to 30 carbon atoms, which may have a substituent, as Q include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a decahydronaphthyl group.

[0025] The linear, branched or cyclic alkyl group having 1 to 30 carbon atoms represented by Q may have a substituent (hereinafter also referred to as a "first substituent"). The first substituent is an aryl group (Ar Sp ); A linear, branched or cyclic alkyl group (R Sp); a linear or cyclic alkenyl group; the alkyl group (R Sp an alkyl group having a divalent heteroatom-containing group in its skeleton in place of at least one methylene group of the above alkenyl group; an alkenyl group having a divalent heteroatom-containing group in its skeleton in place of at least one methylene group of the above alkenyl group; an aryl group (Ar Sp ); a heteroaryl group which may contain a divalent heteroatom instead of a carbon atom in the ring structure of the aryl group; a hydroxy group; a mercapto group; a carboxyl group; a cyano group; a formyl group; and a halogen atom. In the present invention, the divalent heteroatom-containing group is -O-, -CO-, -COO-, -OCO-, -O-CO-O-, -NHCO-, -CONH-, -NH-CO-O-, -O-CO-NH-, -N(R Sp )2-, -N(Ar Sp Among the divalent heteroatom-containing groups, -NHCO-, -CONH-, -NH-CO-O- and -O-CO-NH- each independently represent a hydrogen atom, and R Sp Or Ar Sp may be substituted. Examples of the halogen atom as the first substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. A preferred example of the halogen atom is a fluorine atom.

[0026] The first substituent may be further substituted with a first substituent. When the first substituent has a further first substituent, these substituents may be the same or different within the range of the first substituent options.

[0027] Above R Sp Examples of the linear alkyl group having 1 to 30 carbon atoms as the alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, and an n-dodecyl group. In addition, the linear alkyl group may be an alkenyl group in which at least one carbon-carbon single bond in the linear alkyl group is replaced with a carbon-carbon double bond.

[0028] RSp Examples of the branched alkyl group having 1 to 30 carbon atoms as the alkyl group include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a tert-pentyl group, a 2-ethyloctyl group, and a 2-ethyldecyl group. In addition, the branched alkyl group may be an alkenyl group in which at least one carbon-carbon single bond in the branched alkyl group is replaced with a carbon-carbon double bond.

[0029] R Sp Examples of the cyclic alkyl group having 1 to 30 carbon atoms as the substituent include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a decahydronaphthyl group. Other examples of the cyclic alkyl group include spiro-type cyclic alkyl groups such as spiro[3,4]octyl and spirobicyclopentyl groups; bridged cyclic alkyl groups such as norbornyl, tricyclodecanyl, tetracyclododecanyl and adamantyl groups; and condensed cyclic alkyl groups having decalin and steroid skeletons.

[0030] Ar Sp Examples of the aryl group having 5 to 30 carbon atoms include a cyclopentadienyl group, a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, and an azulenyl group.

[0031] When Q is a linear, branched, or cyclic alkyl group having 1 to 30 carbon atoms and has a first substituent, the total number of carbon atoms of Q, including the substituent, is preferably the above number of carbon atoms. The total number of carbon atoms of Q is preferably 1 to 30, more preferably 4 to 20, and even more preferably 4 to 12. The multiple Q's may be the same or different.

[0032] r is an integer from 0 to 4.

[0033] T is at least one selected from the group consisting of a single bond, a linear, branched or cyclic alkylene group having 1 to 30 carbon atoms which may have a substituent, a linear, branched or cyclic alkenylene group having 2 to 30 carbon atoms which may have a substituent, an arylene group having 5 to 30 carbon atoms which may have a substituent, and a heteroarylene group having 3 to 30 carbon atoms which may have a substituent. At least one methylene group in the above T may be substituted with the above divalent heteroatom-containing group.

[0034] Examples of the linear alkylene group having 1 to 30 carbon atoms as T include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an n-octylene group, and an n-dodecylene group. T may also be an alkenylene group in which at least one of the carbon-carbon single bonds in the linear alkylene group is replaced with a carbon-carbon double bond.

[0035] Examples of the branched alkylene group having 1 to 30 carbon atoms as T include a methylbutylene group, a methylpropylene group, a dimethylethylene group, a dimethylpentylene group, a 2-ethyloctylene group, and a 2-ethyldecylene group. T may also be an alkenylene group in which at least one of the carbon-carbon single bonds in the branched alkylene group is replaced with a carbon-carbon double bond.

[0036] Examples of the cyclic alkylene group having 1 to 30 carbon atoms as T include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cyclooctylene group, and a decahydronaphthylene group. Other examples of the cyclic alkylene group include spiro-type cyclic alkylene groups such as spiro[3,4]octyl and spirobicyclopentyl groups, bridged cyclic alkylene groups such as norbornylene, tricyclodecanylene, tetracyclododecanylene and adamantylene groups, and condensed cyclic alkylene groups having decalin and a steroid skeleton, etc. Furthermore, T may be an alkenylene group in which at least one carbon-carbon single bond in the branched alkyl group is replaced with a carbon-carbon double bond.

[0037] In addition, instead of at least one methylene group of these alkylene groups, the above divalent heteroatom-containing group may be included. Among the above divalent heteroatom-containing groups, the divalent heteroatom-containing group in T is preferably at least one selected from the group consisting of -O-, -S-, -S(O)2-, -CO-, etc. When the alkylene group has two or more divalent heteroatom-containing groups, they may be included in appropriate combination. In addition, these substituents may be included in a ring structure. However, it is preferable that there is no continuous connection of heteroatoms such as -OO-, -SS-, and -OS-. Examples of the alkylene group containing a divalent heteroatom-containing group include alkoxy groups; alkylcarbonyloxy groups; and alkylene groups having a heterocyclic structure such as a lactone structure, a sultone structure, and a lactam structure.

[0038] Examples of the arylene group having 5 to 30 carbon atoms as T include a cyclopentadienylene group, a phenylene group, a naphthylene group, an anthracenylene group, a phenanthrenylene group, and an azulenylene group.

[0039] Examples of the heteroarylene group having 3 to 30 carbon atoms as T include divalent heteroarylene groups having a skeleton such as furan, thiophene, imidazole, pyran, chromene, thianthrene, dibenzothiophene, and xanthene, and aryl imide groups such as a benzimide group. The alkylene group, alkenylene group, arylene group and heteroarylene group represented by T may have a substituent (hereinafter also referred to as a "second substituent"). Examples of the second substituent include the same as the first substituent.

[0040] The second substituent may be further substituted with a second substituent. When the second substituent has a second substituent, these substituents may be the same or different within the range of the second substituent options.

[0041] When the alkylene group, alkenylene group, arylene group, and heteroarylene group represented by T has a second substituent, the total number of carbon atoms of T, including the substituent, is preferably the above number of carbon atoms. When the alkylene group represented by T has a second substituent, T has a total of 1 to 30 carbon atoms, preferably 4 to 20 carbon atoms, and more preferably 4 to 12 carbon atoms. When the alkenylene group represented by T has a second substituent, T has a total of 2 to 30 carbon atoms, preferably 5 to 20 carbon atoms, and more preferably 6 to 12 carbon atoms. When the arylene group represented by T has a second substituent, T has a total of 5 to 30 carbon atoms, preferably 6 to 14 carbon atoms, and more preferably 6 to 11 carbon atoms. When the heteroarylene group represented by T has a second substituent, T has a total of 3 to 30 carbon atoms, preferably 4 to 13 carbon atoms, and more preferably 5 to 10 carbon atoms.

[0042] When a plurality of T's are selected, T is preferably represented by -T1-T2- or -T1-T2-T3-, and T1, T2 and T3 are preferably selected from the same options as T. The total number of carbon atoms in -T1-T2- or -T1-T2-T3- is preferably the same as the total number of carbon atoms in T. It is preferable that T1 and T2 or T1, T2 and T3 are not bonded to the same options.

[0043] L is a single bond or the above divalent heteroatom-containing group. The divalent heteroatom-containing group represented by L is preferably -COO- or -OCO-.

[0044] Z is a group represented by the following formula (2), and the hydrogen atom in Z and R 1 ~R 3 At least one of the hydrogen atoms of the above R is substituted with the above L. 1 ~R 3 If there are multiple, multiple R 1 ~R 3 The hydrogen atom of may be substituted with the above L.

[0045] [ka]

[0046] G is -CO- or -S(O)2-.

[0047] R 1 ~R 3 is any one selected from the group consisting of a hydrogen atom; a halogen atom; a hydroxy group; a mercapto group; a carboxyl group; a sulfonate group; a phosphate group; an optionally substituted diaryl phosphate group having 5 to 30 carbon atoms; an optionally substituted dialkyl phosphate group having 1 to 30 carbon atoms; an optionally substituted alkylaryl phosphate group having 6 to 30 carbon atoms; an optionally substituted amino group; an optionally substituted linear, branched or cyclic alkyl group having 1 to 30 carbon atoms; an optionally substituted linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms; an optionally substituted aryl group having 5 to 30 carbon atoms; and an optionally substituted heteroaryl group having 3 to 30 carbon atoms.

[0048] Above R 1 ~R 3 When there are two or more, R 1 ~R 3 Two of the may be bonded to each other directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, and an alkylene group to form a ring structure.

[0049] Above R 1 ~R 3 At least one methylene group therein may be substituted with a divalent heteroatom-containing group.

[0050] Above R 1 ~R 3 When there are two or more, multiple R 1 ~R 3 may be the same or different.

[0051] R1 ~R 3 The diaryl phosphate group, dialkyl phosphate group, alkylaryl phosphate group, amino group, alkyl group, alkenyl group, aryl group and heteroaryl group as the above may have a substituent (hereinafter also referred to as a "third substituent").

[0052] R 1 ~R 3 The number of carbon atoms of the alkyl group, alkenyl group, aryl group and heteroaryl group as mentioned above is preferably the total number of carbon atoms including the third substituent. R 1 ~R 3 When the amino group as the substituent has a third substituent, the third substituent preferably has 1 to 30 carbon atoms in total.

[0053] Examples of the third substituent include the same as the first substituent.

[0054] The third substituent may be further substituted with a third substituent. When the third substituent has a third substituent, these substituents may be the same or different within the range of the third substituent options.

[0055] R 1 ~R 3 Examples of the linear alkyl group having 1 to 30 carbon atoms as R include linear alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, and an n-dodecyl group. 1 ~R 3 may be an alkenyl group in which at least one of the carbon-carbon single bonds in the linear alkyl group is replaced with a carbon-carbon double bond.

[0056] R 1 ~R 3Examples of the branched alkyl group having 1 to 30 carbon atoms as R include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a tert-pentyl group, a 2-ethyloctyl group, and a 2-ethyldecyl group. 1 ~R 3 may be an alkenyl group in which at least one of the carbon-carbon single bonds in the branched alkyl group is replaced with a carbon-carbon double bond.

[0057] R 1 ~R 3 Examples of the cyclic alkyl group having 1 to 30 carbon atoms as the substituent include a cyclic alkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a decahydronaphthyl group. Other examples of the cyclic alkyl group include spiro-type cyclic alkyl groups such as spiro[3,4]octyl and spirobicyclopentyl groups, bridged cyclic alkyl groups such as norbornyl, tricyclodecanyl, tetracyclododecanyl and adamantyl groups, and condensed cyclic alkyl groups having decalin and steroid skeletons, etc. Also, the branched alkyl group may be an alkenyl group in which at least one carbon-carbon single bond in the branched alkyl group is replaced with a carbon-carbon double bond.

[0058] R 1 ~R 3 Examples of the diaryl phosphate group which may have a substituent as the substituent include a diphenyl phosphate group, a ditolyl phosphate group, and a dixylenyl phosphate group.

[0059] R 1 ~R 3 Examples of the optionally substituted dialkyl phosphate group as the substituent include a dimethyl phosphate group, a diethyl phosphate group, and a diisopropyl phosphate group.

[0060] R 1 ~R 3Examples of the alkylaryl phosphate group which may have a substituent as the substituent include a methylphenyl phosphate group, an ethylphenyl phosphate group, and a propylphenyl phosphate group.

[0061] R 1 ~R 3 Examples of the amino group which may have a substituent as the substituent include a methylamino group, an ethylamino group, an n-butylamino group, an isobutylamino group, a tert-butylamino group, a cyclohexylamino group, a phenylamino group, a 4-iodophenylamino group, a dimethylamino group, a diethylamino group, a di-n-butylamino group, a dicyclohexylamino group, a diphenylamino group, a di-4-iodophenylamino group, a methyl(phenyl)amino group, an ethyl(phenyl)amino group, a methyl(naphthyl)amino group, an isopropyl(phenyl)amino group, and a cyclohexyl(phenyl)amino group.

[0062] Also, R 1 ~R 3 In place of at least one methylene group of the alkyl group in the alkyl group, the divalent heteroatom-containing group may be included. The divalent heteroatom-containing groups may be included in appropriate combination. These substituents may be included in a ring structure. However, it is preferable that the heteroatoms such as -OO-, -SS-, and -OS- are not continuously connected. Examples of the alkyl group containing a divalent heteroatom-containing group include alkoxy groups; alkylcarbonyloxy groups; and alkyl groups having a heterocyclic structure such as a lactone structure, a sultone structure, and a lactam structure.

[0063] R 1 ~R 3 Examples of the aryl group having 5 to 30 carbon atoms include a cyclopentadienyl group, a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, and an azulenyl group.

[0064] R 1 ~R 3Examples of the heteroaryl group having 3 to 30 carbon atoms as the substituent include monovalent heteroaryl groups having a skeleton such as furan, thiophene, imidazole, pyran, chromene, thianthrene, dibenzothiophene, and xanthene.

[0065] The Two R's 1 ~R 3 They may be bonded to each other directly through a single bond; or through at least one selected from the group consisting of a divalent heteroatom-containing group and a linear, branched or cyclic alkylene group having 1 to 30 carbon atoms, which may have a substituent; to form a ring structure. Examples of the ring structure include cyclic alkyl such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane and cyclobutane; cyclic heteroalkyl such as tetrahydrofuran, tetrahydrothiophene, sulfolane, succinimide, γ-lactam, δ-lactam, γ-lactone, δ-lactone, 1,4-dioxane, 1,4-thioxane and 1,4-cyclohexanedione; cyclic heteroalkyl such as pyridine, pyrazine, thiirane, thiazine and 1,3-dioxolan-2-one, aryl such as phenyl and naphthyl; and heteroaryl such as pyridine and thiirane. The ring structure may have a third substituent.

[0066] and l is an integer from 0 to 4. m is an integer from 0 to 5. n is an integer from 0 to 5.

[0067] The two aromatic rings in the above formula (2) may form a ring with a quaternary carbon via a single bond or a divalent heteroatom-containing group. Examples of the ring structure include the following structures, but the present invention is not limited thereto. 1 ~R 3 , G and l are R in the above formula (2). 1 ~R 3 , G, and 1. In the structures below, n′ and m′ are integers of 0 to 4.

[0068] [ka]

[0069] R in Z above 1 ~R 3 and the third substituent may have a halogen atom. 1 ~R 3 And when the third substituent has a halogen atom, the halogen atom is preferably a bromine atom or an iodine atom. From the viewpoint of increasing sensitivity to EUV and EB, the number of bromine atoms or iodine atoms in Z is preferably 1 or more, and the number of bromine atoms or iodine atoms in Z is more preferably 2 or more, and even more preferably 3 or more. From the viewpoint of solubility in the solvent in the resist composition, the number of bromine atoms or iodine atoms in Z is preferably 12 or less, and even more preferably 4 or less.

[0070] It is preferable because the acid diffusibility can be appropriately controlled by the structure represented by the above formula (2) and the atomic radius of the bromine atom or iodine atom. It is also preferable that L in the above formula (1) has an oxygen atom and T is an alkylene group. This is preferable because the solubility of the onium salt in the resist composition is excellent.

[0071] One embodiment of the present invention may be a polymer containing a unit that becomes a repeating unit having the above onium salt.

[0072] The unit that becomes the repeating unit having the onium salt is preferably bonded to the polymer main chain as a side chain of the polymer at at least any arbitrary position selected from the group consisting of the T substituent and the Z substituent.

[0073] Specific examples of the anion of the onium salt represented by the above formula (1) include compound group A and compound group B shown below.

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] <1-2> Cation of onium salt M + is a monovalent onium cation. + is preferably an onium cation having any atom selected from the group consisting of sulfur (S), iodine (I), selenium (Se) and tellurium (Te). + is more preferably a sulfonium cation or an iodonium cation.

[0081] Examples of onium cations having a sulfur (S) atom include the sulfonium cations shown below.

[0082] [ka]

[0083] In the above formula, R a1 ~R a3each independently includes a linear, branched or cyclic alkyl group which may have a substituent (hereinafter referred to as a "fourth substituent"), a linear, branched or cyclic alkenyl group which may have a fourth substituent, an aryl group which may have a fourth substituent, and a heteroaryl group which may have a fourth substituent. R a1 ~R a3 The alkyl group, alkenyl group, aryl group and heteroaryl group are defined as R 1 ~R 3 Preferred examples of the alkyl group, alkenyl group, aryl group and heteroaryl group are the same as those of R. a1 ~R a3 Any two of the above may form a ring structure together with the sulfur atom to which they are bonded, either directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen-containing group, and a methylene group.

[0084] The divalent nitrogen atom-containing group includes, among the divalent heteroatom-containing groups, those containing a nitrogen atom, specifically, -NHCO-, -CONH-, -NH-CO-O-, -O-CO-NH-, -NH-, -N(R Sp )- and -N(Ar Sp )-, etc. are preferred. Sp and Ar Sp is the R of the first substituent Sp and Ar Sp It is the same as R a1 , R a2 and R a3 R when the alkyl group, alkenyl group, aryl group, or heteroaryl group has a fourth substituent a1 , R a2 and R a3 The total number of carbon atoms in the fourth substituent is preferably the above number.

[0085] In the above formula, R a1 ~R a3 When the group is an alkyl group, it preferably has 1 to 15 carbon atoms, and more preferably has 2 to 10 carbon atoms. Above R a1~R a3 Examples of the straight-chain, branched or cyclic alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a tert-pentyl group, a 2-ethylhexyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group.

[0086] In the above formula, R a1 ~R a3 When it is an alkenyl group, it preferably has 2 to 15 carbon atoms, and more preferably has 2 to 10 carbon atoms. Above R a1 ~R a3 Examples of the linear, branched or cyclic alkenyl group include those in which at least one carbon-carbon single bond of the linear alkyl group, branched alkyl group and cyclic alkyl group shown above is replaced with a carbon-carbon double bond. Also, R a1 ~R a3 The alkyl group and alkenyl group may be fluorinated alkyl group and fluorinated alkenyl group in which at least one hydrogen atom in the alkyl group and alkenyl group is substituted with a fluorine atom. All hydrogen atoms may be substituted with the fourth substituent. As the fluorinated alkyl group, a trifluoromethyl group and the like are preferable.

[0087] In the above formula, R a1 ~R a3 When the group is an aryl group, it preferably has 5 to 14 carbon atoms, and more preferably has 5 to 10 carbon atoms.

[0088] In the above formula, R a1 ~R a3 When is a heteroaryl group, it preferably has 3 to 13 carbon atoms, and more preferably has 3 to 10 carbon atoms. Above R a1 ~R a3Examples of the heteroaryl group include monovalent groups having a skeleton such as furan, thiophene, pyrrole, imidazole, pyran, pyridine, pyrimidine, pyrazine, indole, purine, quinoline, isoquinoline, chromene, thianthrene, dibenzothiophene, phenothiazine, phenoxazine, xanthene, acridine, phenazine, and carbazole.

[0089] Examples of the fourth substituent include the same as the first substituent.

[0090] Examples of the onium cation having an iodine (I) atom include the iodonium cations shown below.

[0091] [ka]

[0092] In the above formula, R a4 ~R a5 is the above R a1 ~R a3 The same can be mentioned.

[0093] Examples of onium cations having a selenium (Se) atom include the selenium cations shown below.

[0094] [ka]

[0095] In the above formula, R a6 ~R a8 is the above R a1 ~R a3 The same can be mentioned.

[0096] An example of an onium cation having a tellurium (Te) atom is the tellurium cation shown below.

[0097] [ka]

[0098] In the above formula, R a9 ~R a11 is the above R a1 ~R a3 The same can be mentioned.

[0099] <1-3> Onium salt The onium salt represented by the above formula (1) is a compound having a specific structure represented by the above formula (2) as Z of the anion portion, and is therefore useful as a photoacid generator that efficiently decomposes and generates an acid having a suitable diffusion distance when irradiated with active energy rays such as KrF excimer laser light, ArF excimer laser light, F2 excimer laser light, electron beam (EB), X-rays, and extreme ultraviolet rays (EUV). The onium salt represented by the above formula (1) has the effect of increasing the solubility in a developer by the ring-opening reaction of G in the above formula (2). In addition, the structure represented by the above formula (2) can control the acid diffusibility, and therefore has the effect of reducing the acid diffusion length. Therefore, when used as a photoacid generator for a resist composition, it has excellent resolution in lithography and the effect of reducing LWR (Line width roughness) in fine patterns.

[0100] In some embodiments of the present invention, the development is not limited to aqueous development using an alkaline developer, and aqueous development using a neutral developer, or organic solvent development using an organic solvent developer, etc., may also be used.

[0101] The onium salt is preferably a compound having a molecular weight of 300 to less than 2,000.

[0102] For example, the compound of formula (1) above can be produced by the following method. In addition, M in the following synthesis examples + , A - , Q., T., G., R. 1 ~R 3 , r, n and l are M in the above formula (1). + , A - , Q., T., G., R. 1 ~R 3It is preferable that m' is an integer of 0 to 4. Also, M' + is preferably at least one selected from the group consisting of ammonium cations, alkali metal cations, and alkaline earth metal cations. X1 is preferably at least one selected from the group consisting of chlorine, bromine, iodine, a methanesulfonyl group, a p-toluenesulfonyl group, a trifluoromethanesulfonyl group, and the like. X2 - Or X2 2- represents a monovalent or divalent anion different from the anions of the following formulae (a-1) and (a-11), and is preferably at least one selected from the group consisting of a chloride anion, a bromide anion, a methylsulfate anion, a methanesulfonate anion, a carbonate anion, a sulfonate anion, and the like. R 1 ~R 3 is preferably any one selected from the group consisting of a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms which may have a first substituent, an aryl group having 5 to 30 carbon atoms which may have a substituent, and a heteroaryl group having 3 to 30 carbon atoms which may have a substituent. J is preferably any one selected from the group consisting of an oxygen atom, a sulfur atom, and a hydrogen atom or a nitrogen atom having a substituent.

[0103] [ka]

[0104] [ka]

[0105] [ka]

[0106] The above formula (a-1) and M in Synthesis Example 1-1 + X2 - Or (M + )2X2 2-and react with each other to obtain the above formula (a-2). The above salt exchange reaction is preferably carried out in a solvent. The above formula (a-2) obtained in the above Synthesis Example 1-2-1 or 1-2-2 is reacted with the above formula (a-3) or the above formula (a-5) to obtain the above formula (a-4) or the above formula (a-6).

[0107] [ka]

[0108] The above formula (a-7) or (a-8) and M + X2 - Or (M + )2X2 2- and react with each other to obtain the above formula (a-9) or (a-10). The above salt exchange reaction is preferably carried out in a solvent.

[0109] [ka]

[0110] [ka]

[0111] The above formula (a-3) or (a-5) in the above Synthesis Example 3-1 or 3-2 is reacted with the above formula (a-13) or (a-14) to obtain the above formula (a-11) or (a-15). + X2 - Or (M + )2X2 2- and reacting with the compound of formula (a-12) or (a-16) to obtain the compound of formula (a-16). The salt exchange reaction is preferably carried out in a solvent.

[0112] <2> Photoacid generator One embodiment of the present invention is a photoacid generator containing the above-mentioned onium salt. The photoacid generator contains an onium salt having a specific anion structure, which can improve the characteristics of sensitivity and pattern performance. More specifically, the photoacid generator is characterized by having an anion structure represented by the above formula (1). Specifically, the specific anion structure is that Z in the above formula (1) has a structure represented by the above formula (2). By having the above anion structure, when the developer is alkaline, the solubility in the developer is excellent due to a ring-opening reaction, and the acid diffusibility can be appropriately controlled by the steric effect of Z. In addition, when used in combination with another specific photoacid generator, it can act as a photodegradable base (PDB), which can further improve the characteristics of sensitivity and pattern performance. More specifically, the photoacid generator in some embodiments of the present invention preferably has a pKa of −2 to 6. The pKa is a value obtained by analysis using ACD labs (manufactured by Fujitsu Ltd.).

[0113] <3> polymer One embodiment of the present invention may be a polymer containing a unit that is a repeating unit having the onium salt. That is, the structure is such that the onium salt is bonded to a unit that is a repeating unit (hereinafter, the unit that is a repeating unit may be simply referred to as a unit). Specifically, the onium salt may be bonded to the * portion of the following formula (A) in place of any one of the hydrogen atoms of the onium salt represented by the above formula (1) to form a monomer, and the monomer may be polymerized to form a polymer. For example, the anion structure of the above compound group A and compound group B or M + may be bonded to W in the following formula (A) in place of any one hydrogen atom in the cation structure to form a monomer.

[0114] [ka]

[0115] R in the above formula (A) a is preferably a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms. R aExamples of the linear alkyl group having 1 to 5 carbon atoms as the substituent include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. D is preferably a single bond or the above divalent heteroatom-containing group.

[0116] W is preferably any one selected from the group consisting of a linear, branched or cyclic alkylene group having 1 to 30 carbon atoms which may have a substituent; a linear, branched or cyclic alkenylene group having 2 to 30 carbon atoms which may have a substituent; an arylene group having 5 to 30 carbon atoms which may have a substituent; and a heteroarylene group having 3 to 30 carbon atoms which may have a substituent. The alkylene group, alkenylene group, arylene group and heteroarylene group represented by W may have a substituent (hereinafter also referred to as a "fifth substituent"). Examples of the fifth substituent include the same as the first substituent.

[0117] Examples of the linear alkylene group having 1 to 30 carbon atoms as W include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an n-octylene group, and an n-dodecylene group. The linear alkylene group may be an alkenylene group in which at least one of the carbon-carbon single bonds is replaced with a carbon-carbon double bond.

[0118] Examples of the branched alkylene group having 1 to 30 carbon atoms as W include a methylbutylene group, a methylpropylene group, a dimethylethylene group, a dimethylpentylene group, a 2-ethyloctylene group, and a 2-ethyldecylene group. The branched alkylene group may be an alkenylene group in which at least one of the carbon-carbon single bonds is replaced with a carbon-carbon double bond.

[0119] Examples of the cyclic alkyl group having 1 to 30 carbon atoms as W include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cyclooctylene group, and a decahydronaphthylene group. Other examples of the cyclic alkylene group include spiro-type cyclic alkylene groups such as spiro[3,4]octyl and spirobicyclopentyl groups, bridged cyclic alkylene groups such as norbornyl, tricyclodecanyl, tetracyclododecanyl and adamantyl groups, and condensed cyclic alkylene groups having decalin and steroid skeletons, etc. The branched alkyl group may also be an alkenylene group in which at least one carbon-carbon single bond in the branched alkyl group is replaced with a carbon-carbon double bond.

[0120] In addition, instead of at least one methylene group of these alkylene groups, a divalent heteroatom-containing group may be included. The above divalent heteroatom-containing groups may be included in appropriate combination. Furthermore, these substituents may be included in a ring structure. However, it is preferable that there is no continuous connection of heteroatoms such as -OO-, -SS-, and -OS-. Examples of the alkylene group containing a divalent heteroatom-containing group include alkoxy groups; alkylcarbonyloxy groups; and alkylene groups having a heterocyclic structure such as a lactone structure, a sultone structure, and a lactam structure.

[0121] Examples of the arylene group having 5 to 30 carbon atoms as W include a cyclopentadienyl group, a phenylene group, a naphthylene group, an anthracenylene group, a phenanthrenylene group, and an azulenylene group.

[0122] Examples of the heteroarylene group having 3 to 30 carbon atoms as W include divalent heteroarylene groups having a skeleton such as furan, thiophene, imidazole, pyran, chromene, thianthrene, dibenzothiophene, and xanthene.

[0123] When the alkylene group, alkenylene group, arylene group, or heteroarylene group represented by W has a fifth substituent, the total number of carbon atoms of W, including the substituent, is preferably the above number of carbon atoms.

[0124] The onium salt according to one embodiment of the present invention is preferably added to a resist composition. When the substituent of the onium salt is a polymerizable group, the onium salt may be polymerized to form a polymer containing the onium salt as a unit having an onium salt structure. When the onium salt is a polymer, the M + The total number of carbon atoms in the substituent of , the substituent of T and the substituent of Z is preferably 1 to 30, excluding the number of carbon atoms in the polymer main chain. The above polymer containing an onium salt structure is preferably a polymer having a molecular weight of 2,000 to 100,000.

[0125] The polymer containing the unit having the onium salt according to one embodiment of the present invention may be a homopolymer as long as it contains a unit that functions as a photoacid generator, or may be a copolymer containing other units. In the case of a copolymer, the other units preferably include those that act as an acid-reactive compound and hydroxyaryl group-containing units. The above-mentioned compounds that act as acid-reactive compounds and hydroxyaryl group-containing units will be described later.

[0126] <4> Resist Composition One embodiment of the present invention relates to a resist composition containing a photoacid generator according to some embodiments of the present invention (hereinafter also referred to as a "first photoacid generator").

[0127] The first photoacid generator is decomposed by exposure to active energy rays. Therefore, a resist composition containing the first photoacid generator may be used as a photoresist. In addition, a resist composition containing the first photoacid generator of one embodiment of the present invention as a photodecomposable base, which is one of the acid diffusion controllers, and further containing another specific photoacid generator (hereinafter also referred to as "second photoacid generator") may be used as a photoresist. When the photodecomposable base is contained, the photodecomposable base is decomposed in the exposed area, losing the acid diffusion controllability, and secondary electrons generated by the decomposition act on other photoacid generators, thereby improving the acid generation from the second photoacid generator. On the other hand, in the unexposed area, the photodecomposable base is a salt having a conjugate base weaker than that of the second photoacid generator, so that it can react with the acid generated from the second photoacid generator to inactivate the acid derived from the other photoacid generator, and can act as an acid diffusion controller. Therefore, when the first photoacid generator is used as a photodegradable base in a resist composition, a resist composition that has excellent sensitivity and pattern forming ability properties can be obtained.

[0128] The content of the first photoacid generator in the resist composition according to one embodiment of the present invention is preferably 0.5 to 30 parts by mass, more preferably 1 to 20 parts by mass, and even more preferably 10 to 20 parts by mass, relative to 100 parts by mass of the acid-reactive compound described below. Furthermore, when the first photoacid generator is used as a photodegradable base, i.e., when the resist composition contains a second photoacid generator, the content of the first photoacid generator in the resist composition is preferably 1 to 100 parts by mass, and more preferably 3 to 75 parts by mass, per 100 parts by mass of the second photoacid generator. By containing the first photoacid generator in the resist composition within the above range, it is possible to obtain excellent properties in terms of sensitivity and pattern forming ability. In calculating the content, the organic solvent is not included in the resist composition components. Furthermore, when the first photoacid generator and the second photoacid generator are bonded to a polymer, i.e., when the first photoacid generator or the second photoacid generator is bonded to a unit, the mass is based on the mass excluding the polymer main chain.

[0129] Each component contained in the resist composition will now be described. <4-1> Second photoacid generator The resist composition in some embodiments of the present invention preferably contains a second photoacid generator. The second photoacid generator is not particularly limited as long as it is one that is used in a normal resist composition, and examples thereof include onium salts such as sulfonium salts and iodonium salts, N-sulfonyloxyimide compounds, oxime sulfonate compounds, organic halogen compounds, sulfonyldiazomethane compounds, etc. These may be used alone or in combination of two or more. Examples of sulfonium salts include those described in WO2011 / 093139 and WO2021 / 095356. However, the present invention is not limited thereto.

[0130] As described above, it is preferable to use an anion in the second photoacid generator that has a greater acid strength than the anion in the onium salt of the first photoacid generator. More specifically, the second photoacid generator preferably has a pKa of −3 or less. Examples of such an anion include fluorine atom-substituted sulfonic acid.

[0131] The second photoacid generator may be contained in the resist composition, or may be contained as a unit bound to the polymer. That is, the second photoacid generator may be contained in the polymer as a unit bound to the polymer main chain at any position of the second photoacid generator. For example, when the second photoacid generator is a sulfonium salt, it is preferable that the second photoacid generator has a bond bound to the polymer main chain directly or via a linking group instead of one H of the substituent in the sulfonium salt.

[0132] The content of the second photoacid generator in the resist composition according to one embodiment of the present invention is preferably 1 to 50 parts by mass, more preferably 3 to 50 parts by mass, and even more preferably 5 to 45 parts by mass, relative to 100 parts by mass of the acid-reactive compound described below. When the second photoacid generator is bonded to a polymer, the mass is based on the mass excluding the polymer main chain.

[0133] <4-2> Acid-reactive compounds The resist composition in some aspects of the present invention preferably contains an acid-reactive compound.

[0134] The resist composition containing an acid-reactive compound includes the following I to IV. I: A resist composition containing the above onium salt and an acid-reactive compound. II: A resist composition comprising the above polymer containing a unit having an onium salt, and the above polymer containing a unit having an acid-reactive compound. III: A resist composition comprising a polymer containing a unit having the above onium salt and a unit having the above acid-reactive compound. IV: A resist composition according to the above II or III, further comprising the above onium salt.

[0135] The acid-reactive compound preferably has a protecting group that is deprotected by an acid, is polymerized by an acid, or is crosslinked by an acid. That is, the acid-reactive compound is preferably at least one selected from the group consisting of a compound having a protecting group that is deprotected by an acid, a compound having a polymerizable group that is polymerized by an acid, and a crosslinking agent that has a crosslinking action by an acid.

[0136] The compound having a protecting group that can be deprotected by an acid is a compound that generates a polar group by deprotecting the protecting group by an acid, and changes its solubility in a developer. For example, in the case of aqueous development using an alkaline developer, the compound having a protecting group that can be deprotected by an acid is a compound that is insoluble in an alkaline developer, but becomes soluble in an alkaline developer by deprotecting the protecting group from the compound in an exposed area by the acid generated from the photoacid generator upon exposure.

[0137] In some embodiments of the present invention, the developer is not limited to an alkaline developer, and may be a neutral developer or an organic solvent developer. Therefore, when an organic solvent developer is used, the compound having a protecting group that can be deprotected by an acid is a compound in which the protecting group is deprotected from the compound by the acid generated from the photoacid generator upon exposure to generate a polar group in the exposed area, and the solubility in the organic solvent developer is reduced.

[0138] Examples of the polar group of the acid-reactive compound include a hydroxy group, a carboxy group, an amino group, and a sulfo group. The protecting group to be deprotected with an acid is a group in which the hydrogen atom of the polar group is protected with a protecting group.Specific examples of the protecting group include a tertiary alkyl ester group, an acetal group, a tetrahydropyranyl group, a carbonate group, a siloxy group, and a benzyloxy group.As a compound having the protecting group, a compound having a styrene skeleton, a methacrylate or an acrylate skeleton with these protecting groups pendant thereon is preferably used. The compound having a protecting group that can be deprotected by an acid may be a protecting group-containing low molecular weight compound or a protecting group-containing polymer. In some embodiments of the present invention, the low molecular weight compound has a weight average molecular weight of less than 2,000, and the polymer has a weight average molecular weight of 2,000 or more.

[0139] The compound having a polymerizable group that is polymerized by acid is a compound that changes its solubility in a developer by being polymerized by acid.For example, in the case of aqueous development, it acts on a compound that is soluble in an aqueous developer, and reduces the solubility of the compound in an aqueous developer after polymerization.Specific examples include compounds having an epoxy group, a vinyloxy group, and an oxetanyl group. The compound having a polymerizable group that is polymerizable by an acid may be a polymerizable low molecular weight compound or a polymerizable polymer.

[0140] A crosslinking agent having a crosslinking action by an acid is a compound that changes the solubility in a developer by crosslinking with an acid. For example, in the case of aqueous development, it acts on a compound that is soluble in an aqueous developer, and reduces the solubility of the compound in an aqueous developer after polymerization or crosslinking. Specifically, crosslinking agents having an epoxy group, a vinyloxy group, a 1-alkoxyamino group, an oxetanyl group, etc. can be mentioned. When the compound is a crosslinking agent having a crosslinking action, a compound that reacts with the compound to be crosslinked, that is, the crosslinking agent, and changes the solubility in a developer can be a compound having a phenolic hydroxyl group, etc. The compound capable of crosslinking by an acid may be a polymerizable low molecular weight compound or a polymerizable polymer.

[0141] When the acid-reactive compound is a polymer, in addition to the unit to which the reactive compound is bonded, other units that are usually used in resist compositions may be contained in the polymer. Examples of the other units include a unit (I) having at least one selected from the group consisting of a lactone moiety, a sultone moiety, and a lactam moiety; a unit (II) having at least one selected from the group consisting of a group having an ether bond, an ester bond, an acetal structure, and a hydroxyl group; a hydroxyaryl group-containing unit (III); and the like. Furthermore, the polymer may contain a unit (IV) to which the first photoacid generator is bonded and a unit (V) to which the second photoacid generator is bonded.

[0142] In some embodiments of the present invention, the ratio of each unit of the polymer is not particularly limited, but when the unit to which the acid-reactive compound is bonded is contained as a unit of the same polymer together with other units, the unit to which the acid-reactive compound is bonded preferably accounts for 10 to 70 mol %, more preferably 15 to 65 mol %, and even more preferably 20 to 60 mol %, of all units of the polymer.

[0143] The above unit (I) is preferably 0 to 60 mol%, more preferably 10 to 60 mol%, and even more preferably 20 to 60 mol% of the total. The above unit (II) is preferably 0 to 70 mol%, more preferably 5 to 70 mol%, and even more preferably 10 to 60 mol% of the total. The above unit (III) is preferably 0 to 90 mol%, and even more preferably 10 to 80 mol% of the total. The above unit (IV) is preferably 0 to 30 mol%, more preferably 1 to 30 mol%, and even more preferably 3 to 20 mol%. The above unit (V) is preferably 0 to 30 mol%, more preferably 1 to 30 mol%, and even more preferably 3 to 20 mol%.

[0144] <4-3> Acid diffusion control agent The resist composition according to one embodiment of the present invention may contain an acid diffusion controller. The acid diffusion controller may be the first photoacid generator or the second photoacid generator described above used as a photodegradable base. Further, the acid diffusion controller may be a basic nitrogen-containing organic compound.

[0145] The acid diffusion controller controls the diffusion phenomenon of the acid generated from the photoacid generator in the resist film, and has the effect of controlling undesirable chemical reactions in the non-exposed region. Therefore, the storage stability of the resist composition obtained is further improved, and the pattern properties such as sensitivity and LWR as a resist are further improved, and the line width change of the resist pattern due to the fluctuation of the delay time from exposure to development processing can be suppressed, and a resist composition with excellent process stability can be obtained.

[0146] Examples of the basic nitrogen-containing organic compound include a compound having one nitrogen atom in the same molecule, a compound having two nitrogen atoms, a compound having three nitrogen atoms, an amide group-containing compound, a urea compound, a nitrogen-containing heterocyclic compound, and the like.

[0147] Examples of the nitrogen-containing organic compound include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N,N-dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, amine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, 2,2'-methylenebisaniline, imidazole, 4 Preferred examples of the aryloxy group include 4,4'-methylimidazole, pyridine, 4-methylpyridine, 1,2-di(2-pyridyl)ethane, 1,2-di(4-pyridyl)ethane, 1,2-di(2-pyridyl)ethene, 1,2-di(4-pyridyl)ethene, 1,3-di(4-pyridyl)propane, 1,2-di(4-pyridyloxy)ethane, di(2-pyridyl)ketone, 4,4'-dipyridyl sulfide, 4,4'-dipyridyl disulfide, 2,2'-dipyridylamine, 2,2'-dipicolylamine, and bipyridine.

[0148] As the photodegradable base, a photodegradable base other than the onium salt according to one embodiment of the present invention, which is photosensitive to light upon exposure and generates a weak acid, may be used.Specific examples of the photodegradable base include compounds described in Japanese Patent No. 3577743, JP-A No. 2001-215689, JP-A No. 2001-166476, JP-A No. 2008-102383, JP-A No. 2010-243773, JP-A No. 2011-37835, and JP-A No. 2012-173505.

[0149] When the acid diffusion controller is included, the content thereof is preferably 0.01 to 20 parts by mass, more preferably 0.03 to 15 parts by mass, and even more preferably 0.05 to 10 parts by mass, relative to 100 parts by mass of the acid reactive compound. The above content does not include the first photoacid generator of one embodiment of the present invention.

[0150] <4-4>Water repellent compound The resist composition according to one embodiment of the present invention may contain a water-repellent compound. The water-repellent compound is not particularly limited, but may be one that is commonly used in an immersion lithography process, and preferably has a higher fluorine atom content than the polymer. This allows the water-repellent compound to be unevenly distributed on the surface of the resist film when a resist film is formed using the resist composition due to the water repellency of the water-repellent compound.

[0151] Regarding the fluorine content of the water-repellent compound, it is preferable that 25% or more, and more preferably 50% or more, of the hydrogen atoms in the hydrocarbon groups in the water-repellent compound are fluorinated.

[0152] The content of the water-repellent compound in the resist composition is preferably 0.5 to 10 parts by mass per 100 parts by mass of the above-mentioned polymer (not containing the water-repellent compound) in one embodiment of the present invention, from the viewpoint of improving the hydrophobicity of the resist film. The water-repellent compound may be used alone or in combination of two or more kinds.

[0153] <4-5> Other ingredients In addition to the above-mentioned components, the resist composition of one embodiment of the present invention may contain, as necessary, as optional components, any combination of organic solvents, surfactants, organic carboxylic acids, dissolution inhibitors, stabilizers, dyes, and sensitizing compounds that are typically used in resist compositions.

[0154] Examples of the organic solvent include ethylene glycol monoethyl ether acetate, cyclohexanone, 2-heptanone, propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl β-methoxyisobutyrate, ethyl butyrate, propyl butyrate, methyl isobutyl ketone, ethyl acetate, isoamyl acetate, ethyl lactate, toluene, xylene, cyclohexyl acetate, diacetone alcohol, N-methylpyrrolidone, N,N-dimethylformamide, γ-butyrolactone, N,N-dimethylacetamide, propylene carbonate, ethylene carbonate, etc. These organic solvents are used alone or in combination.

[0155] The surfactant is preferably used to improve the coating property. Examples of the surfactant include nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene polyoxypropylene block copolymers, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters, fluorine-based surfactants, and organosiloxane polymers. The content of the surfactant is preferably 0.0001 to 2 parts by mass, and more preferably 0.0005 to 1 part by mass, relative to 100 parts by mass of the acid-reactive compound.

[0156] Examples of the organic carboxylic acid include aliphatic carboxylic acids, alicyclic carboxylic acids, unsaturated aliphatic carboxylic acids, oxycarboxylic acids, alkoxycarboxylic acids, ketocarboxylic acids, benzoic acid derivatives, phthalic acid, terephthalic acid, isophthalic acid, 2-naphthoic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-3-naphthoic acid, etc. When electron beam exposure is performed under vacuum, there is a risk of the organic carboxylic acid volatilizing from the surface of the resist film and contaminating the inside of the drawing chamber, and therefore preferred organic carboxylic acids are aromatic organic carboxylic acids, and among these, for example, benzoic acid, 1-hydroxy-2-naphthoic acid, and 2-hydroxy-3-naphthoic acid are suitable. The content of the organic carboxylic acid is preferably from 0.01 to 10 parts by mass, more preferably from 0.01 to 5 parts by mass, and even more preferably from 0.01 to 3 parts by mass, based on 100 parts by mass of the acid-reactive compound. The resist composition components are dissolved in the above organic solvent so that the solid content concentration is preferably from 1 to 40 mass %, more preferably from 1 to 30 mass %, and even more preferably from 3 to 20 mass %.

[0157] When the resist composition according to one embodiment of the present invention contains a polymer, the polymer preferably has a weight average molecular weight of 2,000 to 200,000, more preferably 2,000 to 50,000, and even more preferably 2,000 to 15,000. From the viewpoint of sensitivity, the polydispersity (molecular weight distribution) (Mw / Mn) of the polymer is preferably 1.0 to 1.7, and more preferably 1.0 to 1.2. In some embodiments of the present invention, the weight average molecular weight and dispersity of the polymer are defined as polystyrene equivalent values ​​measured by GPC.

[0158] The composition of one embodiment of the present invention can be obtained by mixing the components of the above-mentioned composition, and the mixing method is not particularly limited.

[0159] <5> Device manufacturing methods One aspect of the present invention is a method for manufacturing a device, comprising the steps of forming a resist film by, for example, applying the resist composition onto a substrate, exposing the resist film to light, and developing the exposed resist film. One aspect of the present invention may be a method for manufacturing a substrate having a pattern prior to obtaining individual chips, the method including the steps of forming a resist film using the resist composition, exposing the resist film, and developing the exposed resist film.

[0160] The active energy rays used for exposure in the step of exposing the resist film may be any light that can activate the onium salt of one embodiment of the present invention to generate an acid, and include KrF excimer laser light, ArF excimer laser light, F2 excimer laser light, UV, visible light, X-rays, electron beams, ion beams, i-rays, EUV, and the like. In one embodiment of the present invention, preferred examples of the active energy ray used for exposure in the photolithography process include an electron beam (EB) and extreme ultraviolet ray (EUV).

[0161] The amount of light irradiation varies depending on the type and mixing ratio of each component in the photocurable composition, the thickness of the coating film, etc., but is generally in the range of 1 to 1000 mJ / cm 2 Or 1 to 1000μC / cm 2 It is preferable that: When the resist composition contains the sensitizing compound or contains a corresponding sensitizing compound as a sensitizing unit in a polymer, it is also preferable to carry out a second exposure to ultraviolet light or the like after irradiation with active energy rays. EXAMPLES

[0162] Some aspects of the present invention will be described below based on examples, but the present invention is not limited to these examples in any way.

[0163] <Synthesis of onium salt> <Synthesis of sulfonium salt A-1> 18.1g of sodium 1,1,2-trifluoro-4-tosyloxybutane-1-sulfonate and 19.6g (49.5mmol) of tris(4-fluorophenyl)sulfonium bromide are added with 100g of dichloromethane and 50g of pure water, stirred at room temperature for 2 hours, and then separated. The organic layer is washed with pure water, and the solvent is removed using a rotary evaporator to obtain tris(4-fluorophenyl)sulfonium 1,1,2-trifluoro-4-tosyloxybutane-1-sulfonate in a yield of 94%. 15.0 g of phenolphthalein (Tokyo Chemical Industry Co., Ltd.) and 7.7 g of cesium carbonate are dissolved in 30 g of N-methyl-2-pyrrolidone (NMP), and 21.3 g (31.4 mmol) of tris(4-fluorophenyl)sulfonium 1,1,2-trifluoro-4-tosyloxybutane-1-sulfonate are added. After stirring at 50-55°C for 24 hours, 100 g of dichloromethane and 50 g of 0.01% aqueous hydrochloric acid are added to stop the reaction. The organic layer is washed with pure water, and the solvent is removed using a rotary evaporator to obtain a crude product. The crude product is purified by silica gel chromatography to obtain 22 g (yield 85%) of the target product (sulfonium salt A-1).

[0164] [ka]

[0165] <Synthesis of sulfonium salt A-2> The target product (sulfonium salt A-2) is obtained by carrying out the same operations as in the synthesis of sulfonium salt A-1, except that fluorescein is used instead of phenolphthalein, sodium carbonate is used instead of cesium carbonate, and dioxane is used instead of NMP.

[0166] [ka]

[0167] <Synthesis of sulfonium salt A-3> The target product (sulfonium salt A-3) is obtained by carrying out the same operations as in the synthesis of sulfonium salt A-1, except that 3',3'',5',5''-tetraiodophenolphthalein (Tokyo Chemical Industry Co., Ltd.) is used instead of phenolphthalein and dimethylformamide (DMF) is used instead of NMP.

[0168] [ka]

[0169] <Synthesis of sulfonium salt A-4> The target product (sulfonium salt A-4) is obtained by carrying out the same operations as in the synthesis of sulfonium salt A-1, except that erythrosine B (manufactured by Tokyo Chemical Industry Co., Ltd.) is used instead of phenolphthalein, potassium carbonate is used instead of cesium carbonate, and dimethyl sulfoxide (DMSO) is used instead of NMP.

[0170] [ka]

[0171] <Synthesis of sulfonium salt A-5> The target product (sulfonium salt A-5) is obtained by carrying out the same operations as in the synthesis of sulfonium salt A-1, except that phenolsulfophthalein (manufactured by Tokyo Chemical Industry Co., Ltd.) is used instead of phenolphthalein and sodium hydrogen carbonate is used instead of cesium carbonate.

[0172] [ka]

[0173] <Synthesis of sulfonium salt A-6> Intermediate A-6' is synthesized by using phenylbis[4-(trifluoromethyl)phenyl]sulfonium bromide instead of tris(4-fluorophenyl)sulfonium bromide, and the target product (sulfonium salt A-6) is obtained by carrying out the same operations as in the synthesis of sulfonium salt A-1, except that 3',3'',5',5''-tetraiodophenolphthalein is used instead of phenolphthalein and dimethylformamide (DMF) is used instead of NMP.

[0174] [ka]

[0175] <Synthesis of sulfonium salt A-7> The target product (sulfonium salt A-7) is obtained by carrying out the same operations as in the synthesis of sulfonium salt A-6, except that 4-iodophenylbis[4-(trifluoromethyl)phenyl]sulfonium chloride is used instead of phenylbis[4-(trifluoromethyl)phenyl]sulfonium bromide.

[0176] [ka]

[0177] <Synthesis of sulfonium salt A-8> The target product (sulfonium salt A-8) is obtained by carrying out the same operations as in the synthesis of sulfonium salt A-6, except that triphenylsulfonium methylsulfonate is used instead of phenylbis[4-(trifluoromethyl)phenyl]sulfonium bromide.

[0178] [ka]

[0179] <Synthesis of sulfonium salt A-9> Dissolve 5.00g (6.06mmol) of sulfonium salt A-1 in 30g of acetonitrile, and add 0.51g (6.06mmol) of sodium bicarbonate. Then, add 5g of acetonitrile solution of 1.17g (6.06mmol) of 2-ethylhexyl bromide dropwise over 20 minutes. After stirring at 40°C for 24 hours, add 50g of 1% by mass hydrochloric acid and 60g of dichloromethane to stop the reaction. After separation, wash the organic layer with pure water until it becomes neutral, and then distill off the solvent with a rotary evaporator to obtain a crude product. The crude product is purified by silica gel column chromatography to obtain 4.88g (86% yield) of sulfonium salt A-9.

[0180] [ka]

[0181] <Synthesis of sulfonium salt A-10> The target product (sulfonium salt A-10) is obtained by carrying out the same operations as in the synthesis of sulfonium salt A-9, except that sulfonium salt A-3 is used instead of sulfonium salt A-1, NMP is used instead of acetonitrile, and cesium carbonate is used instead of sodium bicarbonate.

[0182] [ka]

[0183] <Synthesis of sulfonium salt A-11> The target product (sulfonium salt A-11) is obtained by carrying out the same procedure as in the synthesis of sulfonium salt A-10, except that sulfonium salt A-7 is used instead of sulfonium salt A-3.

[0184] [ka]

[0185] <Synthesis of sulfonium salt A-12> Intermediate A-12' was synthesized by carrying out the same procedure as in the synthesis of sulfonium salt A-1, except that tris(4-fluorophenyl)sulfonium 1,1,2-tetrafluoro-6-chlorohexane-1-sulfonate was used instead of tris(4-fluorophenyl)sulfonium 1,1,2-trifluoro-4-tosyloxybutane-1-sulfonate and 3',3'',5',5''-tetraiodophenolphthalein was used instead of phenolphthalein.

[0186] [ka]

[0187] Thereafter, the same procedure as in the synthesis of the sulfonium salt A-10 is carried out except that the intermediate A-12' is used instead of the sulfonium salt A-3, to obtain the target product (sulfonium salt A-12).

[0188] [ka]

[0189] <Synthesis of iodonium salt A-13> Intermediate A-13' was synthesized by carrying out the same procedure as in the synthesis of sulfonium salt A-1, except that diphenyliodonium 1,1,2-trifluoro-4-tosyloxybutane-1-sulfonate was used instead of tris(4-fluorophenyl)sulfonium 1,1,2-trifluoro-4-tosyloxybutane-1-sulfonate and 3',3'',5',5''-tetraiodophenolphthalein was used instead of phenolphthalein.

[0190] [ka]

[0191] Thereafter, the same procedure as in the synthesis of the sulfonium salt A-10 is carried out except that the intermediate A-13' is used instead of the sulfonium salt A-3, to obtain the target product (sulfonium salt A-13).

[0192] [ka]

[0193] <Synthesis of sulfonium salt B-1> 10 g (31.4 mmol) of phenolphthalein and 2.6 g (31.4 mmol) of sodium hydrogen carbonate are added to 40 g of acetonitrile, 2.9 g (15.0 mmol) of 2-ethylhexyl bromide is added, and the mixture is reacted for 20 hours at 50-55° C. 100 g of dichloromethane and 50 g of 0.5% by mass aqueous hydrochloric acid are added to stop the reaction, and then the organic layer is washed with pure water and the solvent is removed using a rotary evaporator to obtain a crude product.

[0194] The crude product is purified by silica gel chromatography, and the resulting organic matter is stirred in 20 g of acetone with 2.3 g (15.0 mmol) of ethyl 4-chlorobutyrate, 1.0 g (7.5 mmol), and 0.8 g (5.0 mmol) of sodium iodide at 40-45°C for 24 hours. 40 g of dichloromethane and 20 g of 0.5% by mass aqueous hydrochloric acid are added to the reaction solution to stop the reaction. The organic layer is washed with pure water, and then 20 g of 1% aqueous hydrochloric acid is added and stirred at 40°C for 17 hours. The organic layer is washed with pure water, and 6.0 g (15.0 mmol) of tris(4-fluorophenyl)sulfonium bromide and 0.8 g (7.5 mmol) of sodium carbonate are added. After stirring at room temperature for 2 hours, the organic layer is separated and washed with pure water. The solvent is then removed using a rotary evaporator, and the product is purified by silica gel chromatography to obtain 10.0 g (80% yield) of the target product (sulfonium salt B-1).

[0195] [ka]

[0196] <Synthesis of sulfonium salt B-2> The target product (sulfonium salt B-2) is obtained by carrying out the same operations as in the synthesis of sulfonium salt B-1, except that 3',3'',5',5''-tetraiodophenolphthalein is used instead of phenolphthalein, cesium carbonate is used instead of sodium bicarbonate, and NMP is used instead of acetonitrile.

[0197] [ka]

[0198] <Synthesis of sulfonium salt B-3> 5.0g (13.3mmol) of 6-carboxyfluorescein (Tokyo Chemical Industry Co., Ltd.) is dissolved in 20g of acetonitrile, 2.2g, 26.6mmol of sodium bicarbonate and 5.2g, 26.6mmol of 2-ethylhexyl bromide are added, and the mixture is reacted at 50-55℃ for 20 hours. After the reaction, the organic layer is concentrated with a rotary evaporator, and 30g of tetrahydrofuran and 10g of 5% by mass aqueous sodium hydroxide are added. After stirring at 50℃ for 6 hours, 20g of 5% by mass aqueous hydrochloric acid and 50g of dichloromethane are added to stop the reaction. The obtained organic layer is washed with pure water, and then 0.7g (6.7mmol) of sodium carbonate and 20g of pure water are added, and 5.3g (13.3mmol) of tris(4-fluorophenyl)sulfonium bromide is added. After stirring at room temperature for 2 hours, the mixture is separated, and the obtained organic layer is washed with pure water. The solvent is then removed using a rotary evaporator to obtain a crude product, which is then purified by silica gel chromatography to obtain 8.8 g (yield 82%) of the target product (sulfonium salt B-3).

[0199] [ka]

[0200] <Synthesis of sulfonium salt B-4> 10.0 g (12.2 mmol) of 3',3'',5',5''-tetraiodophenolphthalein, 2.0 g (6.1 mmol) of cesium carbonate, and 2.8 g (14.6 mmol) of 2-ethylhexyl bromide are added to 50 g of NMP, and the mixture is reacted at 50-55°C for 20 hours. Then, 150 g of 0.5% by mass aqueous hydrochloric acid is added to terminate the reaction. The resulting precipitate is then filtered off, and the solid is vacuum dried to obtain a crude product. The crude product and 3.8 g (48.7 mmol) of pyridine are dissolved in 40 g of NMP, and 2.4 g (11.0 mmol) of hexafluoroglutaric anhydride (Tokyo Chemical Industry Co., Ltd.) are added dropwise under ice cooling. After stirring for 18 hours at 5-10°C, 100 g of pure water is added under ice cooling to terminate the reaction, and the precipitate is filtered off and washed with pure water to obtain a solid. The solid is then added to 50 g of dichloromethane and 20 g of pure water, followed by the addition of 4.5 g (10.4 mmol) of tris(4-fluorophenyl)sulfonium methyl sulfate. After stirring at room temperature for 2 hours, the liquids are separated, and the resulting organic layer is washed with pure water. The solvent is then removed using a rotary evaporator, and the resulting crude product is purified by silica gel chromatography to obtain 13.3 g (73% yield) of the target product (sulfonium salt B-4).

[0201] [ka]

[0202] <Synthesis of sulfonium salt B-5> 5g (14.4mmol) of 5-aminofluorescein and 4.6g (57.6mmol) of pyridine are dissolved in 25g of NMP, and 3.2g (14.4mmol) of hexafluoroglutaric anhydride is added dropwise under ice cooling. After stirring for 12 hours at 5-10°C, 60g of pure water is added under ice cooling to stop the reaction, and the precipitate is filtered and washed with pure water to obtain a solid. Then, the solid is added to 60g of dichloromethane and 30g of pure water, followed by the addition of 6.2g (14.4mmol) of tris(4-fluorophenyl)sulfonium methyl sulfate. After stirring for 2 hours at room temperature, the liquids are separated, and the organic layer is washed with pure water. Then, the solvent is removed using a rotary evaporator, and the resulting crude product is purified by silica gel chromatography to obtain 12.1g (yield 90%) of the target product (sulfonium salt B-5).

[0203] [ka]

[0204] <Synthesis of iodonium salt B-6> The target product (iodonium salt B-6) is obtained by carrying out the same operations as in the synthesis of sulfonium salt B-1 above, except that diphenyliodonium chloride is used instead of tris(4-fluorophenyl)sulfonium bromide.

[0205] [ka]

[0206] <Synthesis of sulfonium salt C-1> The target product (sulfonium salt C-1) is obtained by carrying out the same operations as in the synthesis of sulfonium salt A-1 above, except that bisphenol A is used instead of phenolphthalein and potassium carbonate is used instead of cesium carbonate.

[0207] [ka]

[0208] <Synthesis of sulfonium salt C-2> Intermediate C-2' was synthesized in the same manner as in the synthesis of sulfonium salt A-1, except that tetraiodobisphenol A was used instead of tetraiodophenolphthalein.

[0209] [ka]

[0210] Thereafter, the same procedure as in the synthesis of sulfonium salt A-9 is carried out except that intermediate C-2' is used instead of sulfonium salt A-1 to obtain the target product (sulfonium salt C-2).

[0211] [ka]

[0212] <Synthesis of sulfonium salt C-3> The target product (sulfonium salt C-3) is obtained by carrying out the same operation as in the synthesis of sulfonium salt C-1, except that 2,4,6-triiodophenol is used instead of bisphenol A.

[0213] [ka]

[0214] <Synthesis of sulfonium salt C-4> 12.5g (54.2mmol) of sodium 1,1,2-trifluoro-4-hydroxybutane-1-sulfonate and 19.6g (49.3mmol) of tris(4-fluorophenyl)sulfonium bromide are added with 100g of dichloromethane and 50g of pure water, and the mixture is stirred at room temperature for 2 hours, and then the layers are separated. The resulting organic layer is washed with pure water, and the solvent is removed using a rotary evaporator to obtain 23.8g (92% yield) of tris(4-fluorophenyl)sulfonium 1,1,2-trifluoro-4-hydroxybutane-1-sulfonate.

[0215] The obtained tris(4-fluorophenyl)sulfonium = 1,1,2-trifluoro-4-hydroxybutane-1-sulfonate 20.0g (38.1mmol), N,N-dimethyl-4-aminopyridine 0.44g (3.6mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride 7.3g (38.1mmol) are added to dichloromethane 100g and cooled, and then 1-adamantanecarboxylic acid 6.5g (36.2mmol) is added. After heating to room temperature and stirring for 24 hours, 0.5 mass% hydrochloric acid aqueous solution 35g is added to stop the reaction. The organic layer is washed with pure water, and the solvent is distilled off with a rotary evaporator to obtain a crude product. The crude product is purified by silica gel chromatography to obtain 22.6g (yield 93%) of the target product (sulfonium salt C-4).

[0216] [ka]

[0217] <Synthesis of sulfonium salt C-5> The target product (sulfonium salt C-5) is obtained by carrying out the same operations as in the synthesis of sulfonium salt C-1, except that 7-hydroxycoumarin is used instead of bisphenol A.

[0218] [ka]

[0219] <Synthesis of sulfonium salt D-1> Add 10.0g (72.4mmol) of salicylic acid and 6.1g (72.4mmol) of sodium bicarbonate to pure water and stir for 10 minutes, then add 21.6g (72.4mmol) of triphenylsulfonium chloride. After stirring at room temperature for 1 hour, separate the layers and wash the resulting organic layer with pure water. The solvent is then removed using a rotary evaporator to obtain a crude product. The resulting crude product is purified by silica gel chromatography to obtain 27.2g (yield 94%) of the target product (sulfonium salt D-1).

[0220] [ka]

[0221] <Synthesis of sulfonium salt D-2> The target product (sulfonium salt D-2) is obtained by carrying out the same operation as in the synthesis of sulfonium salt C-1, except that tris(4-fluorophenyl)sulfonium = 1,1,2-trifluoro-4-tosyloxybutane-1-sulfonate is replaced by tris(4-fluorophenyl)sulfonium = 4-chlorobutane-1-acetate.

[0222] [ka]

[0223] Amine D-3 manufactured by Tokyo Chemical Industry Co., Ltd. is used, but the present invention is not limited thereto.

[0224] [ka]

[0225] <Synthesis of Polymer A> 8.0 g of polyhydroxystyrene (weight average molecular weight 8,000) and 0.010 g of 35% by mass aqueous hydrochloric acid solution are dissolved in 28 g of dehydrated dioxane. A solution of 2.73 g of cyclohexyl vinyl ether dissolved in 2.80 g of dehydrated dioxane is dropped into the polyhydroxystyrene solution over 30 minutes. After dropping, the mixture is stirred at 40°C for 2 hours. After stirring and cooling, 0.014 g of dimethylaminopyridine is added to obtain a polymer solution. The polymer solution is then dropped into 260 g of pure water to precipitate the polymer. The solid obtained by separating the polymer through reduced pressure filtration is washed twice with 300 g of pure water, and then vacuum dried to obtain 9.2 g of polymer A shown below as a white solid. The monomer ratio of the polymer unit in the present invention is not limited to the following.

[0226] [ka]

[0227] [Examples 1 to 21 and Comparative Examples 1 to 5] <Electron beam sensitivity evaluation> A sample of the resist composition used in Example 1 is prepared by adding 400 mg of the polymer A resin, 80 mg of the sulfonium salt A-1 synthesized above as a photoacid generator (PAG), and 16 mg of the sulfonium salt D-1 synthesized above as an acid diffusion controller to 5,000 mg of cyclohexanone. The resist compositions used in Examples 2 to 21 and Comparative Examples 1 to 5 are prepared by adding the same amount of polymer A as in Example 1, the same molar amount of photoacid generator as in Example 1, and the same molar amount of acid diffusion controller as in Example 1 to the same amount of cyclohexanone as in Example 1 using each sulfonium salt shown in Table 1. The photoacid generators (PAGs) used in Examples 2 to 21 and Comparative Examples 1 to 5 are the sulfonium salts A-1, A-3, A-4, A-8 to 11, and A-13 and the sulfonium salts C-1 to C-5 obtained above, and the acid diffusion controllers are the sulfonium salts B-1 to B-4, and B-6, the sulfonium salts D-1 to D-2, and the amine D-3 synthesized above.

[0228] The electron beam sensitivity evaluation is carried out as follows. The above resist composition sample is spin-coated onto a silicon wafer pre-modified with hexamethyl disilazane. By pre-baking this on a hot plate at 110 °C for 1 minute, a substrate with a coating film having a thickness of 200 nm is obtained. With respect to the coating film of the substrate, using an electron beam lithography apparatus, exposure is performed while changing the exposure dose so that a 1:1 line and space pattern of 100 nm is formed by an electron beam of 30 keV. The substrate after electron beam irradiation is heated on a hot plate at 110 °C for 1 minute. Then, development is carried out for 1 minute using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide, and then rinsing with pure water gives a 100 nm line and space pattern. The sensitivity by electron beam irradiation is determined with the electron beam irradiation dose at this time being Esize [μC / cm 2 . Also, the obtained pattern is observed and LWR [nm] is measured. For the above other samples, sensitivity evaluation and LWR measurement are also carried out in the same manner as above. The sample compositions and results are shown in Table 1.

[0229] In Table 1, the sensitivity and LWR of each sample are calculated as relative values based on the evaluation results of the samples (Examples 1 to 21 and Comparative Examples 2 to 5) with respect to the sensitivity of Comparative Example 1 (photoacid generator: sulfonium salt C-1, acid diffusion controller: comparative sulfonium salt D-1) being 100 and the LWR being 1. A smaller numerical value for sensitivity and LWR indicates a more excellent effect.

[0230] [Examples 22 to 24 and Comparative Example 6] [EUV Sensitivity Evaluation] Samples of the resist compositions used in Examples 22 to 24 and Comparative Example 6 are prepared by the same method as the electron beam sensitivity evaluation.

[0231] EUV sensitivity evaluation is performed as follows. The resist composition sample is spin-coated onto a silicon wafer that has been previously modified with hexamethylenedisilazane. This is pre-baked on a hot plate at 110°C for 1 minute to obtain a substrate on which a coating film with a thickness of 200 nm has been formed. The coating film on the substrate is irradiated with an EUV exposure device (Energetiq EQ-10m) at various exposure doses. After EUV exposure, the substrate is heated on a hot plate at 110°C for 1 minute. It is then developed for 1 minute using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide, and then rinsed with pure water to obtain a 1 x 1 cm 2 The obtained pattern is subjected to thickness measurement using a contact type thickness meter, and a sensitivity curve is created to obtain the sensitivity Esize [mJ / cm 2 ] is calculated. Esize at this time is the exposure dose when the film thickness becomes 50% of the maximum film thickness. The sample composition and results are shown in Table 2.

[0232] In Table 2, the sensitivity of each sample is calculated as a relative value to the sensitivity of Comparative Example 6 (photoacid generator: sulfonium salt C-1, acid diffusion controller: sulfonium salt D-1) which is set at 100, and the evaluation results of the samples (Examples 22 to 24) relative thereto. A smaller sensitivity value indicates a more excellent effect.

[0233] The onium salts used as the photoacid generators (PAGs) (A-1, A-3, A-4, A-8 to A-11, and A-13 above) and the onium salts used as the photodegradable bases (B-1 to B-4 and B-6 above) are shown below.

[0234] [ka]

[0235] [ka]

[0236] As the acid diffusion controller, comparative sulfonium salts C-1 to C-4, comparative sulfonium salts D-1 and D-2, and amine D-3 are shown below.

[0237] [ka]

[0238] [ka]

[0239] [Table 1]

[0240] [Table 2]

[0241] It can be seen that Examples 4 to 6, 8 to 17, 20, and 21 in Table 1 tend to have better sensitivity than Comparative Examples 1, 4, and 5. From this result, it is presumed that the onium salt in one embodiment of the present invention has a structure having iodine in the phthalein or fluorescein skeleton, and thus has high sensitivity to electron beams, efficiently absorbs active energy rays, and efficiently generates acid. In addition, the resist composition containing the onium salt of Examples 1 to 17 as an acid generator tends to be able to reduce LWR in fine patterns compared to Comparative Examples 1 to 5. This is thought to be because, when an onium salt is contained as an acid generator, the anion structure has a bulky phthalein or fluorescein skeleton, which suppresses acid diffusion, thereby reducing LWR. By containing iodine, which has a large volume and atomic weight, in the skeleton, acid diffusion is further suppressed, and the reduction effect tends to be greater. In addition, the lactone moiety of the phthalein or fluorescein skeleton is hydrolyzed by an alkaline developer, which can improve solubility in the developer, and therefore is thought to play a part in the LWR reduction effect.

[0242] Furthermore, in Examples 12 to 21, the combination of onium salt A-10, onium salt A-13, comparative sulfonium salt C-1, and comparative sulfonium salt C-2 as an acid generator and any one of onium salts B-1 to B-4 and onium salt B-6 as an acid diffusion controller showed improved sensitivity and LWR compared to Comparative Example 1. These results show that the onium salt of one embodiment of the present invention can effectively function as an acid diffusion controller by controlling the diffusion of acid by changing the anion, and that the inclusion of iodine in the structure further increases the sensitivity.

[0243] It can be seen from Table 2 that Examples 22 to 24 tend to have superior sensitivity compared to Comparative Example 6. From these results, it is presumed that the onium salt in one embodiment of the present invention has a structure having iodine in the phthalein or fluorescein skeleton, and thus has high sensitivity to EUV and efficiently generates acid.

[0244] In the above Examples 1 to 24, polymer A was used as the copolymer, but the sulfonium salt of one embodiment of the present invention also tends to have excellent sensitivity and lithography properties such as LWR when combined with a copolymer other than the above polymer A.

[0245] In addition, even if the compound is not an example, as long as it has the structure of the above formula (1), it has a superior effect on sensitivity and LWR compared to the comparative example compounds, similar to the example compounds. Examples of the compound other than the example include the cation (M + ) is selenium or tellurium, or a compound having the anion structure in the above formula (1). Specific examples include the above compound group A and the above compound group B. [Industrial Applicability]

[0246] The onium salt according to one embodiment of the present invention has an anion portion having a moderately bulky phthalein skeleton, and therefore when used in a resist composition, it can moderately control the diffusion of acid, and when the developer is alkaline, the ring-opening reaction of the phthalein skeleton results in excellent solubility in the developer. In addition, when the onium salt is used in a resist composition as a photodecomposable base, which is one of the acid diffusion control agents, the undecomposed onium salt acts as an acid diffusion control agent in the unexposed and exposed areas, and is ionized in the exposed area to generate secondary electrons, which can improve the generation of acid from the photoacid generator, thereby reducing LWR (Line width roughness) in fine patterns in lithography.

Claims

1. An onium salt represented by the following formula (1): 【Chemistry 1】 (In the above formula (1), A － is a sulfonate or carboxylate anion, Q is any one selected from the group consisting of a hydrogen atom; a fluorine atom; and a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms which may have a substituent; r is an integer from 0 to 4; Multiple Q's may be the same or different, T is at least one selected from the group consisting of a single bond; a linear, branched or cyclic alkylene group having 1 to 30 carbon atoms which may have a substituent; a linear, branched or cyclic alkenylene group having 2 to 30 carbon atoms which may have a substituent; an arylene group having 5 to 30 carbon atoms which may have a substituent; and a heteroarylene group having 3 to 30 carbon atoms which may have a substituent; At least one methylene group in T may be substituted with a divalent heteroatom-containing group; L is a single bond or a divalent heteroatom-containing group; Z is a group represented by the following formula (2), which is bonded to L in place of at least one hydrogen atom in the formula (2): M ＋ is a monovalent onium cation. 【Chemistry 2】 (In the formula (2), G is -CO- or -S(O) ２ - and R １ ~R ３ is any one selected from the group consisting of a hydrogen atom; a halogen atom; a hydroxy group; a mercapto group; a carboxyl group; a sulfonate group; a phosphate group; an optionally substituted diaryl phosphate group having 5 to 30 carbon atoms; an optionally substituted dialkyl phosphate group having 1 to 30 carbon atoms; an optionally substituted alkylaryl phosphate group having 6 to 30 carbon atoms; an optionally substituted amino group; an optionally substituted linear, branched or cyclic alkyl group having 1 to 30 carbon atoms; an optionally substituted linear, branched or cyclic alkenyl group having 2 to 30 carbon atoms; an optionally substituted aryl group having 5 to 30 carbon atoms; and an optionally substituted heteroaryl group having 3 to 30 carbon atoms; The R １ ~R ３ When there are two or more, R １ ~R ３ two of the may be bonded to each other directly via a single bond to form a ring structure; or via at least one selected from the group consisting of a divalent heteroatom-containing group and a linear, branched or cyclic alkylene group having 1 to 30 carbon atoms which may have a substituent; The aromatic ring and R in the formula (2) １ ~R ３ may be bonded via a divalent heteroatom-containing group, The two aromatic rings in the formula (2) may form a ring with a quaternary carbon via a single bond or a divalent heteroatom-containing group, The R １ ~R ３ When there are two or more, multiple R １ ~R ３ may be the same or different, The R １ ~R ３ at least one methylene group may be substituted with a divalent heteroatom-containing group; l is an integer from 0 to 4, m is an integer from 0 to 5, and n is an integer from 0 to 5.

2. The above L is -O-, -CO-, -COO-, -OCO-, -O-CO-O-, -NHCO-, -CONH-, -NH-CO-O-, -O-CO-NH-, -O-CO-CH ２ -CO-O-, -CO-CO-O-, -CH ２ -O-CO-, -CH ２ -O-, -CH ２ -O-CO-O-, -S-, -SO-, -S(O) ２ - and -CO-O-CH ２ The onium salt according to claim 1, which is any one selected from the group consisting of --CO--O--.

3. R in the formula (2) １ ~R ３ 3. The onium salt according to claim 1, wherein at least one of the above is an iodine atom.

4. Said M ＋ The onium salt according to any one of claims 1 to 3, wherein is a sulfonium cation or an iodonium cation.

5. A photoacid generator comprising the onium salt according to any one of claims 1 to 4.

6. A polymer comprising a repeating unit having an onium salt according to any one of claims 1 to 4.

7. A resist composition comprising the photoacid generator according to claim 5 or the polymer according to claim 6.

8. The resist composition according to claim 7, further comprising an acid-reactive compound.

9. 9. The resist composition according to claim 8, wherein the acid-reactive compound is at least one selected from the group consisting of a compound having a protecting group which is deprotected by an acid, a compound having a polymerizable group which is polymerized by an acid, and a crosslinking agent which has a crosslinking action by an acid.

10. 10. The resist composition according to claim 7, further comprising an acid diffusion controller.

11. The resist composition according to any one of claims 7 to 10, further comprising a water-repellent compound.

12. forming a resist film on a substrate using the resist composition according to any one of claims 7 to 11; exposing the resist film to active energy rays; and developing the exposed resist film.

13. The method for producing a device according to claim 12, wherein the active energy rays are extreme ultraviolet rays or electron beams.

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