Actinic ray-sensitive or radiation-sensitive resin composition, resist film, pattern formation method, and electronic device production method

Abstract

The present invention provides an actinic ray-sensitive or radiation-sensitive resin composition containing: a resin (A) that has an acid-decomposable group and includes a repeating unit derived from a compound having a styrene skeleton in which the positive charge area of radical cation bodies is less than 150 Å2; an onium salt compound (B) that includes an anion and a cation having at least one fluorine atom, and that generates an acid when being irradiated with actinic rays or radiation; and a boron-containing compound (C).

Description

Actinic ray-sensitive or radiation-sensitive resin composition, resist film, pattern forming method, and method for manufacturing electronic device

[0001] The present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition, a resist film, a pattern forming method, and a method for producing an electronic device.

[0002] Conventionally, in the manufacturing process of semiconductor devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration), microfabrication is performed by lithography using resist compositions. In recent years, with the increasing integration density of integrated circuits, there has been a demand for ultrafine pattern formation in the submicron or quarter-micron range. Accordingly, there has been a trend toward shorter exposure wavelengths, from g-line to i-line and then to KrF excimer laser light, and currently, exposure machines using ArF excimer lasers with a wavelength of 193 nm as a light source have been developed. Furthermore, as a technique for further improving resolution, the so-called immersion method, in which a high refractive index liquid (hereinafter also referred to as "immersion liquid") is filled between the projection lens and the sample, has been developed.

[0003] Currently, in addition to excimer laser light, lithography using electron beams (EB), X-rays, extreme ultraviolet rays (EUV), etc. is also being developed. Accordingly, resist compositions that are effectively sensitive to various types of actinic rays or radiation have been developed.

[0004] Various additives are used in actinic ray-sensitive or radiation-sensitive resin compositions for the purpose of improving performance. For example, Patent Document 1 discloses a resist composition containing a boron-containing compound.

[0005] Japanese Patent Application Publication No. 2011-81358

[0006] In recent years, for example, in pattern formation using EUV or electron beams, as patterns are formed with finer features, further improvements in various performances are required. In particular, there is room for improvement in resolution and roughness performance. In the case of line and space patterns, roughness performance includes, for example, line width roughness (LWR) performance.

[0007] An object of the present invention is to provide an actinic ray-sensitive or radiation-sensitive resin composition that is excellent in resolution and roughness performance in forming ultrafine patterns (for example, a line-and-space pattern with a line width of 20 nm or less, or a hole pattern with a hole diameter of 20 nm or less), a resist film formed from the actinic ray-sensitive or radiation-sensitive resin composition, a pattern formation method that uses the actinic ray-sensitive or radiation-sensitive resin composition, and a method for manufacturing an electronic device.

[0008] The present inventors have found that the above problems can be solved by the following configuration.

[0009] [1] The positive charge area of ​​the radical cation is 150 Å ２ an actinic ray-sensitive or radiation-sensitive resin composition comprising: a resin (A) having an acid-decomposable group and including a repeating unit derived from a compound having a styrene skeleton of less than 100; an onium salt compound (B) having a cation having at least one fluorine atom and an anion, the onium salt compound generating an acid upon irradiation with actinic rays or radiation; and a boron-containing compound (C).

[0010] [2] The actinic ray-sensitive or radiation-sensitive resin composition according to [1], wherein the repeating unit derived from the compound having a styrene skeleton is a repeating unit derived from a compound represented by the following general formula (1):

[0011]

[0012] In the general formula (1), Rb represents a hydrogen atom or a monovalent organic group. ３represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group, or a halogenated alkyl group. Ar represents an aromatic ring group. R １ represents a hydroxy group or a carboxy group. ２ represents a substituent other than a hydroxy group or a carboxy group. p is an integer of 1 or more and 9 or less. q is an integer of 0 or more and 8 or less. R １ , R ２ When a plurality of R are present, they may be the same or different. ２ and Rb may be bonded to each other to form a ring.

[0013] [3] The actinic ray-sensitive or radiation-sensitive resin composition according to [1] or [2], wherein the resin (A) contains 30 mass% or more of repeating units derived from the compound having a styrene skeleton, based on all repeating units. [4] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [3], wherein the boron-containing compound (C) is a compound represented by the following general formula (2C):

[0014]

[0015] In general formula (2C), R ５ｃ ~R ８ｃ each independently represents an alkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group. ＋ represents an organic cation or an inorganic cation. m represents an integer of 1 or more. When m represents an integer of 2 or more, a plurality of R ５ｃ When m is an integer of 2 or more, a plurality of R ６ｃ When m is an integer of 2 or more, a plurality of R ７ｃ When m is an integer of 2 or more, a plurality of R ８ｃ When m is an integer of 2 or more, a plurality of Y ＋ may be the same or different.

[0016] [5] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [4], wherein the boron-containing compound (C) is a compound represented by the following general formula (3C):

[0017]

[0018] In general formula (3C), R ９ｃ ~R １３ｃ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom. ＋ represents an organic cation or an inorganic cation. m represents an integer of 1 or more. ９ｃ may be the same or different. １０ｃ may be the same or different. １１ｃ may be the same or different. １２ｃ may be the same or different. １３ｃ When m is an integer of 2 or more, a plurality of Y ＋ may be the same or different.

[0019] [6] Y ＋ [7] The actinic ray-sensitive or radiation-sensitive resin composition according to [4] or [5], wherein Y is a sulfonium cation or an iodonium cation. ＋ [8] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [7], wherein is a triarylsulfonium cation or a diaryliodonium cation. [9] A resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [7].

[0020] [9] A pattern forming method comprising the steps of: forming a resist film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [7]; exposing the resist film to light; and developing the exposed resist film with a developer to form a pattern.

[10] A method for producing an electronic device, comprising the pattern forming method according to [9].

[0021] According to the present invention, it is possible to provide an actinic ray-sensitive or radiation-sensitive resin composition that is excellent in resolution and roughness performance in forming an ultrafine pattern (for example, a line-and-space pattern with a line width of 20 nm or less, a hole pattern with a hole diameter of 20 nm or less, etc.), a resist film formed from the actinic ray-sensitive or radiation-sensitive resin composition, a pattern formation method that uses the actinic ray-sensitive or radiation-sensitive resin composition, and a method for manufacturing an electronic device.

[0022] The present invention will be described in detail below. The following description of the components may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.

[0023] As used herein, "actinic rays" or "radiation" refers to, for example, the bright line spectrum of a mercury lamp, far ultraviolet rays typified by excimer lasers, extreme ultraviolet rays (EUV), X-rays, electron beams (EB), etc. As used herein, "light" refers to actinic rays or radiation.

[0024] Unless otherwise specified, "exposure" in this specification includes not only exposure using the bright line spectrum of a mercury lamp, far ultraviolet light typified by an excimer laser, extreme ultraviolet light, X-rays, EUV light, etc., but also drawing using particle beams such as electron beams and ion beams. In this specification, the word "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0025] In the present specification, when a group (atomic group) is referred to without specifying whether it is substituted or unsubstituted, it encompasses both unsubstituted and substituted groups, unless it is contrary to the spirit of the present invention. For example, the term "alkyl group" encompasses not only unsubstituted alkyl groups (unsubstituted alkyl groups) but also substituted alkyl groups (substituted alkyl groups). Furthermore, the term "organic group" in this specification refers to a group containing at least one carbon atom. Unless otherwise specified, the substituent is preferably a monovalent substituent. Examples of the substituent include monovalent nonmetallic atomic groups excluding hydrogen atoms, which can be selected, for example, from the following substituents T:

[0026] (Substituent T) The substituent T is a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; an alkoxy group such as a methoxy group, an ethoxy group, or a tert-butoxy group; a cycloalkoxy group; an aryloxy group such as a phenoxy group or a p-tolyloxy group; an alkoxycarbonyl group such as a methoxycarbonyl group, a butoxycarbonyl group, or a phenoxycarbonyl group; an acyloxy group such as an acetoxy group, a propionyloxy group, or a benzoyloxy group; an acyl group such as an acetyl group, a benzoyl group, an isobutyryl group, an acryloyl group, a methacryloyl group, or a methoxalyl group; Examples of the alkyl group include alkylsulfanyl groups such as phenylsulfanyl and p-tolylsulfanyl; arylsulfanyl groups such as phenylsulfanyl and p-tolylsulfanyl; alkyl groups; cycloalkyl groups; aryl groups; heteroaryl groups; hydroxyl groups; carboxy groups; formyl groups; sulfo groups; cyano groups; alkylaminocarbonyl groups; arylaminocarbonyl groups; sulfonamide groups; silyl groups; amino groups; imino groups; monoalkylamino groups; dialkylamino groups; arylamino groups, nitro groups; formyl groups; thiol groups; thioether groups; and combinations thereof. The alkyl groups may be either linear or branched. Furthermore, when the alkyl group contains a fluorine atom, it may be a perfluoroalkyl group. Furthermore, the cycloalkyl groups, aryl groups, and heteroaryl groups may be either monocyclic or polycyclic.

[0027] The bonding direction of divalent groups represented in this specification is not limited unless otherwise specified. For example, when Y is -COO- in a compound represented by the formula "X-Y-Z", Y may be -CO-O- or -O-CO-. In addition, the compound may be "X-CO-O-Z" or "X-O-CO-Z".

[0028] In this specification, the weight average molecular weight (Mw), number average molecular weight (Mn), and dispersity (also referred to as molecular weight distribution) (Mw / Mn) of a resin are defined as polystyrene-equivalent values ​​measured by gel permeation chromatography (GPC) using a GPC apparatus (HLC-8120GPC manufactured by Tosoh Corporation) (solvent: tetrahydrofuran, flow rate (sample injection amount): 10 μL, column: TSK gel Multipore HXL-M manufactured by Tosoh Corporation, column temperature: 40° C., flow rate: 1.0 mL / min, detector: differential refractive index detector).

[0029] In this specification, the acid dissociation constant (pKa) refers to the pKa in an aqueous solution, and specifically, is a value determined by calculation based on a database of Hammett's substituent constants and known literature values ​​using the following software package 1. All pKa values ​​described in this specification are values ​​determined by calculation using this software package.

[0030] Software package 1: Advanced Chemistry Development (ACD / Labs) Software V8.14 for Solaris (1994-2007 ACD / Labs).

[0031] On the other hand, pKa can also be determined by molecular orbital calculation. A specific method for this is to calculate the pKa of H in an aqueous solution based on the thermodynamic cycle. ＋ One method is to calculate the dissociation free energy. ＋The dissociation free energy can be calculated by, for example, DFT (density functional theory), but various other methods have been reported in the literature, and the method is not limited to these. There are several software programs that can perform DFT, and Gaussian 16 is an example.

[0032] As described above, the pKa in this specification refers to a value calculated using software package 1 based on a database of Hammett's substituent constants and publicly known literature values, but if the pKa cannot be calculated by this method, a value obtained by Gaussian 16 based on DFT (density functional theory) will be used. Furthermore, as described above, the pKa in this specification refers to "pKa in aqueous solution," but if the pKa in aqueous solution cannot be calculated, "pKa in dimethyl sulfoxide (DMSO) solution" will be used.

[0033] In this specification, examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0034] In this specification, the term "solid content" refers to components that form a resist film and does not include solvents. Furthermore, any component that forms a resist film is considered to be a solid content even if it is in a liquid state.

[0035] [Actinic Ray- or Radiation-Sensitive Resin Composition] The actinic ray- or radiation-sensitive resin composition of the present invention (also referred to as "resist composition") has a radical cation form having a positive charge area of ​​150 Å. ２ The actinic ray-sensitive or radiation-sensitive resin composition comprises: a resin (A) having an acid-decomposable group and containing a repeating unit derived from a compound having a styrene skeleton of less than 1000; an onium salt compound (B) containing a cation having at least one fluorine atom and an anion, and generating an acid upon irradiation with actinic rays or radiation; and a boron-containing compound (C).

[0036] The reason why the resist composition provides excellent resolution and roughness performance in the formation of ultrafine patterns (for example, line and space patterns with line widths of 20 nm or less, and hole patterns with hole diameters of 20 nm or less) is not necessarily clear, but the inventors of the present invention speculate as follows.

[0037] When a film (resist film) formed from the resist composition of the present invention is irradiated with actinic rays or radiation, a large number of radical cations and electrons of the resin (A) are generated in the film, and electrons may transfer from the orbital of the highly electron-donating boron-containing compound (C) to the radical cation of the resin (A). As a result, the radical cation of the resin (A) becomes a neutral radical, and electrons generated during irradiation with actinic rays or radiation and present in the system are transferred to this neutral radical of the resin (A), generating a radical anion of the resin (A). In other words, in the resist film formed from the resist composition, the presence of the boron-containing compound results in excellent generation efficiency of the radical anion of the resin (A). Furthermore, since the resin (A) contains a repeating unit derived from a compound having a styrene skeleton in which the positive charge area of ​​the radical cation is less than a predetermined value, coupling between the radical cation and the radical anion of the resin (A) is less likely to occur, and electron deactivation is suppressed. Therefore, it is presumed that electron transfer from the radical anion of the resin (A) to the photoacid generator is facilitated, accelerating the decomposition of the photoacid generator and the generation of generated acid in the exposed area. As a result, the difference in dissolution rate in the developer between the unexposed area and the exposed area (so-called dissolution contrast) increases, and resolution and roughness performance are improved. Furthermore, since the onium salt compound (B), which generates acid upon irradiation with actinic rays or radiation, contains a cation having at least one fluorine atom, the photodecomposition property of the onium salt is improved, and therefore resolution and roughness performance are further improved.

[0038] The various components contained in the resist composition will now be described.

[0039] [Resin (A)] The resist composition contains a radical cation having a positive charge area of ​​150 Å. ２The resin (A) contains a repeating unit derived from a compound having a styrene skeleton of less than 1 / 2 and has an acid-decomposable group. The resin (A) is a resin having a group (acid-decomposable group) that decomposes under the action of an acid to generate a polar group, and is preferably a resin containing a repeating unit having an acid-decomposable group. The acid-decomposable resin is typically a resin that decomposes under the action of an acid to increase its polarity. The acid-decomposable resin's polarity increases under the action of an acid, increasing its solubility in an alkaline developer and decreasing its solubility in an organic solvent. In other words, when pattern formation is carried out using an acid-decomposable resin, typically, a positive pattern is preferably formed when an alkaline developer is used as the developer, and a negative pattern is preferably formed when an organic solvent-based developer is used as the developer.

[0040] <Positive charge area of ​​radical cation is 150 Å ２ The resin (A) contains a repeating unit derived from a compound having a styrene skeleton in which the positive charge area of ​​the radical cation form is less than 150 Å. ２ In this specification, the compound having a styrene skeleton means, in addition to styrene, a compound in which any hydrogen atom in styrene is substituted with a substituent, a compound having another aromatic ring in place of the benzene ring in styrene, and a compound in which any hydrogen atom in styrene is substituted with a substituent and has another aromatic ring in place of the benzene ring in styrene.

[0041] The positive charge area of ​​the radical cation of the compound having a styrene skeleton is 150 Å ２ From the viewpoint of enhancing the effect of the present invention, the positive charge area of ​​the radical cation is less than 120 Å. ２ Preferably, it is 100 Å or less. ２ More preferably, 90 Å or less ２ The lower limit of the positive charge area of ​​the radical cation is not particularly limited, but is usually 50 Å. ２ or more, and ２ It may be 70 Å or more. ２It may be more than that.

[0042] The positive charge area of ​​a radical cation of a compound having a styrene skeleton can be calculated as follows. An optimization calculation is performed on the structure of the compound having a styrene skeleton after releasing one electron (radical cation), and the surface charge density of the optimized structure is calculated by the Conductor-Like Screening Model for Realistic Solvation method (COSMO-RS method). The positive charge area is calculated when the surface charge density per unit area is −0.015 e / Å. ２ ~-0.025e / Å ２ Each calculation is performed using Gaussian 16 software under the conditions of B3LYP / 6-31+G(d,p). At this time, the solvent effect of water is taken into account using the Integral Equation Formalism Polarizable Continuum Model (IEFPCM method).

[0043] The positive charge area of ​​the radical cation of a compound having a styrene skeleton can be adjusted by the type and number of substituents and the type of aromatic ring. For example, when the substituent has an alkoxy group, a trialkylsilyl group, an alkenyl group, an alkynyl group, or the like, the positive charge area tends to be smaller. On the other hand, when the substituent has a hydroxy group, a carboxy group, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a thiol group, an alkylthio group, an alkoxycarbonyl group, a cyano group, a halogen, or the like, the positive charge area tends to be larger. In addition, when a polycyclic ring such as a naphthalene ring is used instead of the benzene ring in styrene, the positive charge area tends to be larger.

[0044] The repeating unit derived from the compound having a styrene skeleton is preferably a repeating unit derived from a compound represented by the following general formula (1).

[0045]

[0046] In the general formula (1), Rb represents a hydrogen atom or a monovalent organic group. ３represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group, or a halogenated alkyl group. Ar represents an aromatic ring group. R １ represents a hydroxy group or a carboxy group. ２ represents a substituent other than a hydroxy group or a carboxy group. p is an integer of 1 or more and 9 or less. q is an integer of 0 or more and 8 or less. R １ , R ２ When a plurality of R are present, they may be the same or different. ２ and Rb may be bonded to each other to form a ring.

[0047] In general formula (1), Rb represents a hydrogen atom or a monovalent organic group. The monovalent organic group represented by Rb is not particularly limited, but examples thereof include alkyl groups. The alkyl group may be either linear or branched, and examples thereof include alkyl groups having 1 to 20 carbon atoms, preferably alkyl groups having 1 to 10 carbon atoms, and more preferably alkyl groups having 1 to 6 carbon atoms. Rb preferably represents a hydrogen atom.

[0048] In general formula (1), R ３ represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group or a halogenated alkyl group.

[0049] R ３ Examples of the alkyl group represented by the formula (I) include linear or branched alkyl groups having 1 to 4 carbon atoms, and a methyl group is preferred.

[0050] R ３ Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a chlorine atom, a bromine atom, or an iodine atom being preferred, and a chlorine atom being more preferred.

[0051] R ３ The alkyl group in the alkylsulfonyl group represented by the formula: is a linear or branched alkyl group having 1 to 6 carbon atoms, and a methyl group or an ethyl group is preferred.

[0052] R ３ Examples of the alkyl group in the alkoxy group represented by the formula (I) include the alkyl groups in the alkylsulfonyl group described above, and preferred examples are also the same.

[0053] R ３ Examples of the alkyl group in the acyl group (alkylcarbonyl group or arylcarbonyl group) represented by the formula (I) include the alkyl group in the alkylsulfonyl group described above, and preferred examples are also the same. Examples of the aryl group include aryl groups having 6 to 12 carbon atoms, and a phenyl group is preferred.

[0054] R ３ Examples of the alkyl group in the alkyl ester group (alkylcarbonyloxy group) represented by the formula: include the alkyl groups in the alkylsulfonyl group described above, and preferred examples are also the same.

[0055] R ３ Examples of the alkyl group in the halogenated alkyl group represented by the formula (I) include the alkyl group in the alkylsulfonyl group described above, and preferred examples are also the same. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is more preferred.

[0056] R ３ The above group represented by the following formula (I) may further have a substituent, if possible. Examples of the substituent include the above-mentioned substituent T.

[0057] R ３ is more preferably a hydrogen atom.

[0058] In the general formula (1), Ar represents an aromatic ring group. The aromatic ring in the aromatic ring group of Ar may be an aromatic hydrocarbon ring or an aromatic heterocyclic ring.

[0059] The aromatic hydrocarbon ring may be a monocyclic ring or a polycyclic ring. The number of ring atoms is preferably 6 to 15, more preferably 6 to 10. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring. Of these, a benzene ring or a naphthalene ring is preferred, and a benzene ring is more preferred.

[0060] The aromatic heterocycle may be a monocycle or a polycycle. The number of ring atoms is preferably 5 to 15. Examples of the heterocycle having aromaticity include a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, a pyridine ring, an indole ring, a benzodiazole ring, and a carbazole ring.

[0061] Ar is a group obtained by removing (p+q+1) hydrogen atoms from an aromatic ring. Ar is preferably a group obtained by removing (p+q+1) hydrogen atoms from a benzene ring.

[0062] In general formula (1), R １ represents a hydroxy group or a carboxy group, and is preferably a hydroxy group. In general formula (1), p represents an integer of 1 to 9, and is preferably 1. In other words, the compound represented by general formula (1) is preferably a compound having one hydroxy group.

[0063] In general formula (1), R ２ represents a substituent other than a hydroxy group and a carboxy group. Examples of the substituent other than a hydroxy group and a carboxy group include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a thiol group, an alkylthio group, an alkoxycarbonyl group, a halogen atom, an alkoxy group, and a trialkylsilyl group.

[0064] R ２ Examples of the alkyl group represented by the formula (I) include linear or branched alkyl groups having 1 to 4 carbon atoms, and a methyl group is preferred.

[0065] R ２ The alkenyl group represented by the formula (I) includes a straight-chain or branched-chain alkenyl group having 2 to 4 carbon atoms.

[0066] R ２ The alkynyl group represented by the formula (I) includes a straight-chain or branched-chain alkynyl group having 2 to 4 carbon atoms.

[0067] R ２ The aryl group represented by the formula (I) includes an aryl group having 6 to 12 carbon atoms, and a phenyl group is preferred.

[0068] R ２ Examples of the alkyl group in the alkylthio group represented by the formula: include the alkyl groups described above, and the preferred examples are also the same.

[0069] R ２ Examples of the alkyl group in the alkoxycarbonyl group represented by the formula: include the alkyl groups described above, and the preferred examples are also the same.

[0070] R ２ Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a bromine atom being preferred.

[0071] R ２ Examples of the alkyl group in the alkoxy group represented by the formula (I) include the alkyl groups described above, and the preferred examples are also the same.

[0072] R ２ Examples of the alkyl group in the trialkylsilyl group represented by the formula: include the alkyl groups described above, and the preferred examples are also the same.

[0073] In general formula (1), q is an integer of 0 or more and 8 or less, preferably an integer of 0 to 4, and more preferably an integer of 0 to 2.

[0074] The repeating unit derived from the compound represented by the above general formula (1) is preferably a repeating unit derived from a compound represented by the following general formula (2).

[0075]

[0076] In general formula (2), Ar １ represents a benzene ring group or a naphthalene ring group. ２ represents a substituent other than a hydroxy group or a carboxy group, and r is an integer of 0 or more and 2 or less.

[0077] R in general formula (2) ２ represents R in general formula (1). ２ The same applies to preferred examples.

[0078] The positive charge area of ​​the radical cation is 150 Å. ２Examples of compounds having a styrene skeleton of less than 1000 mJ / mol are listed below, but are not limited thereto. Me represents a methyl group.

[0079]

[0080] The content of the specific repeating unit is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, based on the total repeating units in the resin (A), and the upper limit thereof is preferably 60% by mass or less, more preferably 50% by mass or less, based on the total repeating units in the resin (A).

[0081] <Repeating unit having acid-decomposable group> The acid-decomposable group preferably has a structure in which a polar group is protected with a leaving group that is eliminated by the action of an acid. Hereinafter, the acid-decomposable group will be described, and then the repeating unit having the acid-decomposable group will be described.

[0082] (Acid-decomposable group) The acid-decomposable group refers to a group that decomposes under the action of an acid to generate a polar group. The acid-decomposable group preferably has a structure in which the polar group is protected by a leaving group that is released under the action of an acid. The acid-decomposable group can decompose under the action of an acid to generate a polar group. The polar group is preferably an alkali-soluble group, and examples thereof include acidic groups such as a carboxyl group, a phenolic hydroxyl group, a fluorinated alcohol group, a sulfonic acid group, a phosphate group, a sulfonamide group, a sulfonylimide group, a (alkylsulfonyl) (alkylcarbonyl) methylene group, a (alkylsulfonyl) (alkylcarbonyl) imide group, a bis(alkylcarbonyl) methylene group, a bis(alkylcarbonyl) imide group, a bis(alkylsulfonyl) methylene group, a bis(alkylsulfonyl) imide group, a tris(alkylcarbonyl) methylene group, and a tris(alkylsulfonyl) methylene group, as well as an alcoholic hydroxyl group. Of these, the polar group is preferably a carboxyl group, a phenolic hydroxyl group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), or a sulfonic acid group.

[0083] Examples of the leaving group that is eliminated by the action of an acid include groups represented by formulae (Y1) to (Y4). Formula (Y1): —C(Rx １) (Rx ２ ) (Rx ３ ) Formula (Y2): -C(=O)OC(Rx １ ) (Rx ２ ) (Rx ３ ) Formula (Y3): -C(R ３６ ) (R ３７ ) (OR ３８ ) Formula (Y4): -C(Rn)(H)(Ar)

[0084] In formula (Y1) and formula (Y2), Rx １ ~Rx ３ Each of Rx independently represents a linear or branched alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group. １ ~Rx ３ may be bonded to form a ring.

[0085] In addition, Rx １ ~Rx ３ When all of Rx are linear or branched alkyl groups, １ ~Rx ３ At least two of Rx are preferably methyl groups. １ ~Rx ３ As the alkyl group, a linear or branched alkyl group is preferred, and a linear alkyl group is more preferred.

[0086] Rx １ ~Rx ３ The linear or branched alkyl group represented by Rx is preferably a linear alkyl group. １ ~Rx ３ The number of carbon atoms in the linear or branched alkyl group represented by the formula (I) is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3. １ ~Rx ３ Specific examples of the linear or branched alkyl group represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.

[0087] Rx １ ~Rx ３ The cycloalkyl group represented by the formula (I) may be either a monocyclic or polycyclic group. １~Rx ３ The number of carbon atoms in the cycloalkyl group represented by Rx is preferably 6 to 15, and more preferably 6 to 10. １ ~Rx ３ Specific examples of the cycloalkyl group represented by the formula (I) include monocyclic cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group; and polycyclic cycloalkyl groups such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group.

[0088] Rx １ ~Rx ３ The alkenyl group is preferably a vinyl group.

[0089] Rx １ ~Rx ３ The aryl group is preferably an aryl group having 6 to 10 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthryl group.

[0090] Also, Rx １ ~Rx ３ may be bonded to form a ring. The ring may be either a monocyclic or polycyclic ring. The ring is preferably a cycloalkyl group, more preferably a 5- or 6-membered monocyclic cycloalkyl group. Specific examples of the ring include monocyclic cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group; and polycyclic cycloalkyl groups such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group. Rx １ ~Rx ３ In the cycloalkyl group formed by bonding these two, for example, one of the methylene groups constituting the ring may be replaced with a heteroatom such as an oxygen atom, a group having a heteroatom such as a carbonyl group, or a vinylidene group. Furthermore, in these cycloalkyl groups, one or more of the ethylene groups constituting the cycloalkane ring may be replaced with a vinylene group. The group represented by formula (Y1) or formula (Y2) can be, for example, Rx １ is a methyl group or an ethyl group, and Rx ２ and Rx ３and Rx are preferably bonded to form the above-described cycloalkyl group. When the resist composition is, for example, a resist composition for EUV exposure, １ ~Rx ３ and Rx １ ~Rx ３ The ring formed by combining these two groups preferably further has a fluorine atom or an iodine atom as a substituent.

[0091] In formula (Y3), R ３６ ~R ３８ R each independently represents a hydrogen atom or a monovalent organic group. ３７ and R ３８ may be bonded to each other to form a ring. ３６ is also preferably a hydrogen atom. Examples of the monovalent organic group include a linear or branched alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group. One or more methylene groups in the linear or branched alkyl group, cycloalkyl group, aryl group, and aralkyl group may be substituted with a group selected from the group consisting of heteroatoms such as oxygen atoms and atomic groups having heteroatoms such as carbonyl groups. In other words, the linear or branched alkyl group, cycloalkyl group, aryl group, and aralkyl group may contain atomic groups having heteroatoms such as oxygen atoms and atomic groups having heteroatoms such as carbonyl groups. In addition, in the repeating unit having an acid-decomposable group described later, R ３８ may bond with another substituent on the main chain of the repeating unit to form a ring. ３８ The group formed by bonding together R and another substituent on the main chain of the repeating unit is preferably an alkylene group such as a methylene group. ３６ ~R ３８ and a monovalent organic group represented by R ３７ and R ３８ The ring formed by bonding these groups together preferably further has a fluorine atom or an iodine atom as a substituent.

[0092] Formula (Y3) is preferably a group represented by the following formula (Y3-1).

[0093]

[0094] Here, L １ and L ２ Each independently represents a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group, an aryl group, or a group combining these (for example, a group combining a linear or branched alkyl group and an aryl group). M represents a single bond or a divalent linking group. Q represents a linear or branched alkyl group that may contain heteroatoms, a cycloalkyl group that may contain heteroatoms, an aryl group that may contain heteroatoms, an amino group, an ammonium group, a mercapto group, a cyano group, an aldehyde group, or a group combining these (for example, a group combining a linear or branched alkyl group and a cycloalkyl group). In the linear or branched alkyl group and cycloalkyl group, for example, one of the methylene groups may be replaced with a group selected from heteroatoms such as oxygen atoms and atomic groups having heteroatoms such as carbonyl groups. It should be noted that L １ and L ２ It is preferred that one of Q, M, and L is a hydrogen atom, and the other is a linear or branched alkyl group, a cycloalkyl group, an aryl group, or a group in which an alkylene group and an aryl group are combined. １ At least two of the groups may be bonded to form a ring (preferably a 5- or 6-membered ring). ２ is preferably a secondary or tertiary alkyl group, and more preferably a tertiary alkyl group. Examples of secondary alkyl groups include an isopropyl group, a cyclohexyl group, and a norbornyl group, and examples of tertiary alkyl groups include a tert-butyl group and an adamantane group. In these embodiments, the Tg (glass transition temperature) and activation energy of the resin (A) are increased in the repeating unit having an acid-decomposable group, which will be described later, and therefore, in addition to ensuring film strength, fogging can be suppressed.

[0095] When the resist composition is, for example, a resist composition for EUV exposure, L １ and L ２ It is also preferred that the linear or branched alkyl group, cycloalkyl group, aryl group, and combinations thereof represented by the formula (I) further have a fluorine atom or an iodine atom as a substituent. Furthermore, it is also preferred that the linear or branched alkyl group, cycloalkyl group, aryl group, and aralkyl group have one methylene group replaced with a group selected from heteroatoms such as oxygen atoms and atomic groups containing heteroatoms such as carbonyl groups. Furthermore, when the resist composition is, for example, a resist composition for EUV exposure, it is also preferred that the heteroatom in the linear or branched alkyl group which may contain a heteroatom, cycloalkyl group which may contain a heteroatom, aryl group which may contain a heteroatom, amino group, ammonium group, mercapto group, cyano group, aldehyde group, and combinations thereof represented by Q be a heteroatom selected from the group consisting of fluorine atom, iodine atom, and oxygen atom.

[0096] In formula (Y4), Ar represents an aromatic ring group. Rn represents a linear or branched alkyl group, a cycloalkyl group, or an aryl group. Rn and Ar may be bonded to each other to form a non-aromatic ring. Ar is more preferably an aryl group. When the resist composition is, for example, a resist composition for EUV exposure, the aromatic ring group represented by Ar and the linear or branched alkyl group, cycloalkyl group, and aryl group represented by Rn preferably have a fluorine atom and an iodine atom as a substituent.

[0097] In terms of further improving acid decomposability, when a non-aromatic ring is directly bonded to the polar group (or a residue thereof) in the leaving group protecting the polar group, it is also preferable that the ring atom in the non-aromatic ring adjacent to the ring atom directly bonded to the polar group (or a residue thereof) does not have a halogen atom such as a fluorine atom as a substituent.

[0098] The leaving group that is eliminated by the action of an acid may also be a 2-cyclopentenyl group having a substituent (such as an alkyl group), such as a 3-methyl-2-cyclopentenyl group, or a cyclohexyl group having a substituent (such as an alkyl group), such as a 1,1,4,4-tetramethylcyclohexyl group.

[0099] (Repeating unit containing an acid-decomposable group) Next, a repeating unit containing an acid-decomposable group that the resin (A) may contain will be described. The repeating unit containing an acid-decomposable group may be a repeating unit corresponding to the specific repeating unit described above, or may be a different repeating unit, but is preferably a repeating unit different from the specific repeating unit. As the repeating unit containing an acid-decomposable group, in addition to the repeating units containing an acid-decomposable group described above, a repeating unit represented by the following formula (A) is also preferred.

[0100]

[0101] L １ represents a divalent linking group which may have a fluorine atom or an iodine atom. １ represents a hydrogen atom, a fluorine atom, an iodine atom, an alkyl group which may have a fluorine atom or an iodine atom, or an aryl group which may have a fluorine atom or an iodine atom. ２ represents a leaving group which is eliminated by the action of an acid and which may have a fluorine atom or an iodine atom. １ , R １ , and R ２ At least one of L preferably has a fluorine atom or an iodine atom. １ represents a divalent linking group which may have a fluorine atom or an iodine atom. Examples of the divalent linking group which may have a fluorine atom or an iodine atom include -CO-, -O-, -S-, -SO-, and -SO ２ -, hydrocarbon groups which may have a fluorine atom or an iodine atom (for example, linear or branched alkylene groups, cycloalkylene groups, alkenylene groups, arylene groups, etc.), and linking groups in which a plurality of these groups are linked together. １As the arylene group, -CO-, an arylene group, or -arylene group-straight-chain or branched-chain alkylene group having a fluorine atom or an iodine atom- is preferred, and -CO- or -arylene group-straight-chain or branched-chain alkylene group having a fluorine atom or an iodine atom- is more preferred. As the arylene group, a phenylene group is preferred. The number of carbon atoms in the straight-chain or branched-chain alkylene group is not particularly limited, but is preferably 1 to 10, more preferably 1 to 3. The total number of fluorine atoms and iodine atoms contained in the straight-chain or branched-chain alkylene group having a fluorine atom or an iodine atom is not particularly limited, but is preferably 2 or more, more preferably 2 to 10, and even more preferably 3 to 6.

[0102] R １ represents a hydrogen atom, a fluorine atom, an iodine atom, a straight-chain or branched-chain alkyl group which may have a fluorine atom or an iodine atom, or an aryl group which may have a fluorine atom or an iodine atom. The number of carbon atoms in the straight-chain or branched-chain alkyl group is not particularly limited, but is preferably 1 to 10, and more preferably 1 to 3. The total number of fluorine atoms and iodine atoms contained in the straight-chain or branched-chain alkyl group which has a fluorine atom or an iodine atom is not particularly limited, but is preferably 1 or more, more preferably 1 to 5, and even more preferably 1 to 3. The straight-chain or branched-chain alkyl group which has a fluorine atom or an iodine atom may contain a heteroatom other than a halogen atom, such as an oxygen atom.

[0103] R ２ represents a leaving group which is eliminated by the action of an acid and which may have a fluorine atom or an iodine atom. Examples of the leaving group which may have a fluorine atom or an iodine atom include the leaving groups represented by the above formulae (Y1) to (Y4) and leaving groups which are represented by the above formulae (Y1) to (Y4) and which have a fluorine atom or an iodine atom, and preferred embodiments are also the same.

[0104] Furthermore, the repeating unit having an acid-decomposable group is preferably a repeating unit represented by formula (AI).

[0105]

[0106] In formula (AI), Xa １ represents a hydrogen atom or an alkyl group which may have a substituent. T represents a single bond or a divalent linking group. Rx １ ~Rx ３ Each of Rx independently represents a linear or branched alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group. １ ~Rx ３ may be bonded to form a ring.

[0107] In addition, Rx １ ~Rx ３ When all of Rx are linear or branched alkyl groups, １ ~Rx ３ At least two of Rx are preferably methyl groups. １ ~Rx ３ As the alkyl group, a linear or branched alkyl group is preferred, and a linear alkyl group is more preferred.

[0108] Xa １ Examples of the alkyl group represented by the formula (I) which may have a substituent include a methyl group or a —CH ２ -R １１ Examples of the group include a group represented by R １１ represents a halogen atom (such as a fluorine atom), a hydroxyl group, or a monovalent organic group, and examples thereof include an alkyl group having 5 or less carbon atoms which may be substituted with a halogen atom, an acyl group having 5 or less carbon atoms which may be substituted with a halogen atom, and an alkoxy group having 5 or less carbon atoms which may be substituted with a halogen atom, and an alkyl group having 3 or less carbon atoms is preferred, and a methyl group is more preferred. １ is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

[0109] Examples of the divalent linking group represented by T include an alkylene group, an aromatic ring group, a -COO-Rt- group, and a -O-Rt- group. In the formula, Rt represents a linear or branched alkylene group or a cycloalkylene group. T is preferably a single bond or a -COO-Rt- group. When T represents a -COO-Rt- group, Rt is preferably an alkylene group having 1 to 5 carbon atoms, and is preferably a -CH２ -, -(CH ２ ) ２ - or -(CH ２ ) ３ - is more preferable.

[0110] Rx １ ~Rx ３ The linear or branched alkyl group represented by Rx is preferably a linear alkyl group. １ ~Rx ３ The number of carbon atoms in the linear or branched alkyl group represented by the formula (I) is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3. １ ~Rx ３ Specific examples of the linear or branched alkyl group represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.

[0111] Rx １ ~Rx ３ The cycloalkyl group represented by the formula (I) may be either a monocyclic or polycyclic group. １ ~Rx ３ The number of carbon atoms in the cycloalkyl group represented by Rx is preferably 6 to 15, and more preferably 6 to 10. １ ~Rx ３ Specific examples of the cycloalkyl group represented by the formula (I) include monocyclic cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group; and polycyclic cycloalkyl groups such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group.

[0112] Rx １ ~Rx ３ The alkenyl group is preferably a vinyl group.

[0113] Rx １ ~Rx ３ The aryl group is preferably an aryl group having 6 to 10 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthryl group.

[0114] Also, Rx １ ~Rx ３may be bonded to form a ring. The ring may be either a monocyclic or polycyclic ring. The ring is preferably a cycloalkyl group, more preferably a 5- or 6-membered monocyclic cycloalkyl group. Specific examples of the ring include monocyclic cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group; and polycyclic cycloalkyl groups such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group. Rx １ ~Rx ３ In the cycloalkyl group formed by bonding these two, for example, one of the methylene groups constituting the ring may be replaced with a heteroatom such as an oxygen atom, a group having a heteroatom such as a carbonyl group, or a vinylidene group. Furthermore, in these cycloalkyl groups, one or more of the ethylene groups constituting the cycloalkane ring may be replaced with a vinylene group.

[0115] The repeating unit represented by formula (AI) is, for example, Rx １ is a methyl group or an ethyl group, and Rx ２ and Rx ３ and are preferably bonded to form the above-mentioned cycloalkyl group.

[0116] When each of the above groups has a substituent, examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), a carboxyl group, and an alkoxycarbonyl group (having 2 to 6 carbon atoms).

[0117] The repeating unit represented by formula (AI) is preferably an acid-decomposable (meth)acrylic acid tertiary alkyl ester repeating unit (Xa １ represents a hydrogen atom or a methyl group, and T represents a single bond).

[0118] (Repeating unit having an acid-decomposable group containing an unsaturated bond) The resin (A) preferably has a repeating unit having an acid-decomposable group containing an unsaturated bond as a repeating unit having an acid-decomposable group. As the repeating unit having an acid-decomposable group containing an unsaturated bond, a repeating unit represented by formula (B) is preferred.

[0119]

[0120] In formula (B), Xb represents a hydrogen atom, a halogen atom, or an alkyl group which may have a substituent. L represents a single bond or a divalent linking group which may have a substituent. Ry １ ~Ry ３ each independently represents a hydrogen atom, a linear or branched alkyl group, a monocyclic or polycyclic cycloalkyl group, an alkenyl group, an alkynyl group, or a monocyclic or polycyclic aryl group. １ ~Ry ３ Any two of Ry may be bonded to form a monocyclic or polycyclic ring (for example, a monocyclic or polycyclic cycloalkyl group or cycloalkenyl group). １ ~Ry ３ At least one of R represents an alkenyl group, an alkynyl group, a monocyclic or polycyclic cycloalkenyl group, or a monocyclic or polycyclic aryl group, or R １ ~Ry ３ Any two of Ry bond to each other to form a monocyclic or polycyclic alicyclic ring (for example, a monocyclic or polycyclic cycloalkyl group or cycloalkenyl group). １ ~Ry ３ Two or more of Ry are not hydrogen atoms. １ ~Ry ３ When any one of R represents a hydrogen atom, R １ ~Ry ３ two other groups bond to each other to form a ring having one or more vinylene groups in the ring structure, and at least one of the vinylene groups is １ ~Ry ３ A hydrogen atom represented by any one of the following is present adjacent to the carbon atom to which it is bonded.

[0121] Ry １ ~Ry ３ The alkyl group of Ry is preferably an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a t-butyl group. １ ~Ry ３The cycloalkyl group of Ry is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group. １ ~Ry ３ The aryl group in Ry is preferably an aryl group having 6 to 15 carbon atoms, more preferably an aryl group having 6 to 10 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthryl group. １ ~Ry ３ The alkenyl group in Ry is preferably a vinyl group. １ ~Ry ３ The alkynyl group in Ry is preferably an ethynyl group. １ ~Ry ３ The cycloalkenyl group of Ry is preferably a structure containing a double bond in a part of a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group. １ ~Ry ３ The cycloalkyl group formed by combining the above two is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, and is also preferably a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group. Of these, a monocyclic cycloalkyl group having 5 to 6 carbon atoms is preferred. １ ~Ry ３ The cycloalkyl group and cycloalkenyl group formed by bonding two of the above are, for example, those in which one of the methylene groups constituting the ring is substituted with a heteroatom such as an oxygen atom, a carbonyl group, or —SO ２ - group, and -SO ３ These cycloalkyl groups and cycloalkenyl groups may have one or more ethylene groups constituting the cycloalkane ring and cycloalkene ring replaced with a vinylene group. １ ~Ry ３ A preferred embodiment of the combination is, for example, Ry １is a methyl group, an ethyl group, a vinyl group, an allyl group, or an aryl group, and Ry ２ and Rx ３ and R are bonded to form the above-mentioned cycloalkyl group or cycloalkenyl group, and １ is a hydrogen atom, and Ry ２ and Ry ３ are bonded to each other to form a ring having one or more vinylene groups in the ring structure, and at least one of the vinylene groups is Ry １ and a hydrogen atom represented by the formula (I) is present adjacent to the carbon atom to which the hydrogen atom is bonded.

[0122] Ry １ ~Ry ３ When further having a substituent, examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), a carboxyl group, and an alkoxycarbonyl group (having 2 to 6 carbon atoms).

[0123] The alkyl group represented by Xb, which may have a substituent, is, for example, a methyl group or —CH ２ -R １１ Examples of the group include a group represented by the following formula: １１ represents a halogen atom (such as a fluorine atom), a hydroxyl group, or a monovalent organic group, and examples thereof include an alkyl group having 5 or less carbon atoms which may be substituted with a halogen atom, an acyl group having 5 or less carbon atoms which may be substituted with a halogen atom, and an alkoxy group having 5 or less carbon atoms which may be substituted with a halogen atom, and an alkyl group having 3 or less carbon atoms is preferred, and a methyl group is more preferred. Xb is preferably a hydrogen atom, a fluorine atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

[0124] Examples of the divalent linking group represented by L include a -Rt- group, a -CO- group, a -COO-Rt- group, a -COO-Rt-CO- group, a -Rt-CO- group, and a -O-Rt- group, with a -Rt- group, a -CO- group, a -COO-Rt-CO- group, or a -Rt-CO- group being preferred. Rt represents a linear or branched alkylene group, a cycloalkylene group, or an aromatic ring group, with an aromatic ring group being preferred. The aromatic ring group may have a substituent such as a halogen atom, a hydroxyl group, or an alkoxy group.

[0125] When each of the groups in formula (B) has a substituent, examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), a carboxyl group, and an alkoxycarbonyl group (having 2 to 6 carbon atoms).

[0126] The repeating unit represented by formula (B) is preferably an acid-decomposable (meth)acrylic acid tertiary ester repeating unit (a repeating unit in which Xb represents a hydrogen atom or a methyl group and L represents a —CO— group), an acid-decomposable hydroxystyrene tertiary alkyl ether repeating unit (a repeating unit in which Xb represents a hydrogen atom or a methyl group and L represents a phenyl group), or an acid-decomposable styrene carboxylic acid tertiary ester repeating unit (a repeating unit in which Xb represents a hydrogen atom or a methyl group and L represents a —Rt—CO— group (Rt is an aromatic group)).

[0127] Specific examples of repeating units having an acid-decomposable group containing an unsaturated bond include the repeating units described in paragraphs

[0067] to

[0071] of WO 2022 / 024928.

[0128] The content of the repeating unit having an acid-decomposable group in the resin (A) is preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass, based on the total repeating units in the resin (A), and the upper limit thereof is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less.

[0129] The resin (A) may contain other repeating units in addition to the repeating units described above. Examples of other repeating units include at least one repeating unit selected from the group consisting of Group A below. Group A: A group consisting of the following repeating units (20) to (26). (20) A repeating unit having an acid group, as described below. (21) A repeating unit having a fluorine atom or an iodine atom and having neither an acid-decomposable group nor an acid group, as described below. (22) A repeating unit having a lactone group, a sultone group, or a carbonate group, as described below. (23) A repeating unit having a photoacid-generating group, as described below. (24) A repeating unit represented by formula (V-1) or the following formula (V-2), as described below. (25) A repeating unit for reducing the mobility of the main chain. (26) A repeating unit having an alicyclic hydrocarbon structure and not exhibiting acid decomposability, as described below.

[0130] When the resist composition is used as a resist composition for EUV exposure, it is preferable that the resin (A) has at least one repeating unit selected from the group consisting of Group A. Furthermore, when the resist composition is used as a resist composition for EUV exposure, it is preferable that the resin (A) has at least one of a fluorine atom and an iodine atom. When the resin (A) contains both a fluorine atom and an iodine atom, the resin (A) may have one repeating unit containing both a fluorine atom and an iodine atom, or the resin (A) may have two repeating units: a repeating unit containing a fluorine atom and a repeating unit containing an iodine atom. Furthermore, when the resist composition is used as a resist composition for EUV exposure, it is also preferable that the resin (A) has a repeating unit containing an aromatic group.

[0131] <Repeating Unit Having an Acid Group> The resin (A) may have a repeating unit having an acid group that does not correspond to the specific repeating units described above. The acid group is preferably an acid group having a pKa of 13 or less. As described above, the acid dissociation constant of the acid group is preferably 13 or less, more preferably 3 to 13, and even more preferably 5 to 10. When the resin (A) has an acid group having a pKa of 13 or less, the content of the acid group in the resin (A) is not particularly limited, but is often 0.2 to 6.0 mmol / g. Of these, 0.8 to 6.0 mmol / g is preferred, 1.2 to 5.0 mmol / g is more preferred, and 1.6 to 4.0 mmol / g is even more preferred. When the content of the acid group is within the above range, development proceeds smoothly, and the formed pattern shape is excellent, and resolution is also excellent. Preferred examples of the acid group include a carboxyl group, a hydroxyl group, a phenolic hydroxyl group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), a sulfonic acid group, a sulfonamide group, or an isopropanol group, with a phenolic hydroxyl group being more preferred. The phenolic hydroxyl group refers to a hydroxyl group substituted on a ring atom of an aromatic ring. In addition, one or more fluorine atoms (preferably one to two) of the hexafluoroisopropanol group may be substituted with a group other than a fluorine atom (such as an alkoxycarbonyl group). The -C(CF) thus formed may be ３ )(OH)—CF ２ - is also preferred as an acid group. In addition, one or more fluorine atoms may be substituted with a group other than a fluorine atom to form -C(CF ３ )(OH)—CF ２ The repeating unit having an acid group is preferably a repeating unit different from the repeating unit having a structure in which a polar group is protected with a leaving group that is eliminated by the action of an acid, and a repeating unit having a lactone group, a sultone group, or a carbonate group, which will be described later. The repeating unit having an acid group may have a fluorine atom or an iodine atom.

[0132] As the repeating unit having an acid group, a repeating unit having a phenolic hydroxyl group is preferable in terms of achieving the effects of the present invention more excellently. Examples of the repeating unit having a phenolic hydroxyl group include a repeating unit represented by the following formula (1):

[0133]

[0134] In formula (1), A represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, or a cyano group. R represents a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkenyl group, an aralkyl group, an alkoxy group, an alkylcarbonyloxy group, an alkylsulfonyloxy group, an alkyloxycarbonyl group, or an aryloxycarbonyl group, and when there are multiple Rs, they may be the same or different. When there are multiple Rs, they may combine with each other to form a ring. R is preferably a hydrogen atom. a represents an integer of 1 to 3. b represents an integer of 0 to (5-a).

[0135] Specific examples of repeating units having a phenolic hydroxyl group include the following repeating units: wherein a represents 1 or 2.

[0136]

[0137] Other specific examples of repeating units having an acid group can be found in, for example, paragraphs

[0088] to

[0089] and

[0103] to

[0110] of WO 2022 / 024928.

[0138] The content of repeating units having an acid group that do not correspond to the above-mentioned specific repeating units is preferably 20% by mass or more, more preferably 30% by mass or more, based on the total repeating units in the resin (A), and the upper limit thereof is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, based on the total repeating units in the resin (A).

[0139] <Repeating units that have neither an acid-decomposable group nor an acid group, but have a fluorine atom or an iodine atom> In addition to the above-mentioned <specific repeating units>, <repeating units having an acid-decomposable group>, and <repeating units having an acid group>, the resin (A) may have a repeating unit that has a fluorine atom or an iodine atom (hereinafter also referred to as unit X). Furthermore, the <repeating units that have a fluorine atom or an iodine atom> here is preferably different from other types of repeating units belonging to Group A, such as the <repeating units that have a lactone group, a sultone group, or a carbonate group> and the <repeating units that have a photoacid-generating group> described below.

[0140] The unit X is preferably a repeating unit represented by formula (C).

[0141]

[0142] L ５ represents a single bond or an ester group. ９ represents a hydrogen atom or an alkyl group which may have a fluorine atom or an iodine atom. １０ represents a hydrogen atom, an alkyl group which may have a fluorine atom or an iodine atom, a cycloalkyl group which may have a fluorine atom or an iodine atom, an aryl group which may have a fluorine atom or an iodine atom, or a group which is a combination of these.

[0143] The content of units X is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, based on the total repeating units in resin (A), and the upper limit is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less.

[0144] Among the repeating units of the resin (A), the total content of repeating units containing at least one of a fluorine atom and an iodine atom is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and particularly preferably 40% by mass or more, based on the total repeating units of the resin (A). The upper limit is not particularly limited, but is, for example, 70% by mass or less. Examples of repeating units containing at least one of a fluorine atom and an iodine atom include repeating units having a fluorine atom or an iodine atom and an acid-decomposable group, repeating units having a fluorine atom or an iodine atom and an acid group, and repeating units having a fluorine atom or an iodine atom.

[0145] <Repeating unit having a lactone group, a sultone group, or a carbonate group> From the viewpoint of improving the effects of the present invention, it is also preferable that the resin (A) has a repeating unit having at least one selected from the group consisting of a lactone group, a sultone group, and a carbonate group (hereinafter also referred to as "unit Y"). It is also preferable that the unit Y does not have a hydroxyl group or an acid group such as a hexafluoropropanol group.

[0146] The lactone group or sultone group may have a lactone structure or a sultone structure. The lactone structure or sultone structure is preferably a 5- to 7-membered lactone structure or a 5- to 7-membered sultone structure. Among these, a 5- to 7-membered lactone structure to which another ring structure is fused, forming a bicyclo or spiro structure, or a 5- to 7-membered sultone structure to which another ring structure is fused, forming a bicyclo or spiro structure, is more preferred. Resin (A) preferably has a repeating unit having a lactone group or sultone group formed by abstracting one or more hydrogen atoms from a ring atom of a lactone structure represented by any one of formulas (LC1-1) to (LC1-21) below, or a sultone structure represented by any one of formulas (SL1-1) to (SL1-3) below. Furthermore, the lactone group or sultone group may be directly bonded to the main chain. For example, the ring atom of the lactone group or sultone group may constitute the main chain of resin (A).

[0147]

[0148] The lactone structure or sultone structure portion may have a substituent (Rb ２ ) may have a preferable substituent (Rb ２ ) includes an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, a carboxyl group, a halogen atom, a cyano group, and an acid-decomposable group. n2 represents an integer of 0 to 4. When n2 is 2 or more, a plurality of Rb ２ may be different, and multiple Rb ２ They may be bonded to each other to form a ring.

[0149] Examples of repeating units having a group having a lactone structure represented by any one of formulas (LC1-1) to (LC1-21) or a sultone structure represented by any one of formulas (SL1-1) to (SL1-3) include repeating units represented by the following formula (AI):

[0150]

[0151] In formula (AI), Rb ０ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. ０ Preferred substituents that the alkyl group of Rb may have include a hydroxyl group and a halogen atom. ０ Examples of the halogen atom in Rb include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. ０ is preferably a hydrogen atom or a methyl group. Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent group formed by combining these. Among these, a single bond or -Ab １ -CO ２ A linking group represented by - is preferred. １is a linear or branched alkylene group, or a monocyclic or polycyclic cycloalkylene group, and is preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group, or a norbornylene group. V is a group obtained by removing one hydrogen atom from a ring member atom of a lactone structure represented by any of formulas (LC1-1) to (LC1-21), or a group obtained by removing one hydrogen atom from a ring member atom of a sultone structure represented by any of formulas (SL1-1) to (SL1-3).

[0152] When optical isomers exist in the repeating unit having a lactone group or a sultone group, any optical isomer may be used. One optical isomer may be used alone, or multiple optical isomers may be used in combination. When one optical isomer is primarily used, its optical purity (ee) is preferably 90 or more, more preferably 95 or more.

[0153] The carbonate group is preferably a cyclic carbonate ester group. Examples of repeating units having a cyclic carbonate ester group include the repeating units described in paragraphs

[0127] to

[0133] of WO 2022 / 024928.

[0154] The content of the unit Y is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, based on all repeating units in the resin (A), and the upper limit thereof is preferably 85% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, and particularly preferably 60% by mass or less, based on all repeating units in the resin (A).

[0155] <Repeating unit having a photoacid generating group> As described below, the resin (A) may be integrated with a photoacid generator. That is, the resin (A) may have a structure in which the photoacid generator is integrated with the resin (A). When the photoacid generator is integrated with the resin (A), the resin (A) contains a repeating unit having a photoacid generating group. Examples of such repeating units include repeating units represented by the following formula (4):

[0156]

[0157] R ４１represents a hydrogen atom or a methyl group. ４１ represents a single bond or a divalent linking group. ４２ represents a divalent linking group. ４０ represents a photoacid generating group. ４０ The photoacid generating group represented by the formula (I) is preferably a group obtained by removing one hydrogen atom from a photoacid generator described later, and more preferably a group obtained by removing one hydrogen atom from the anion moiety of a photoacid generator having an onium salt structure described later.

[0158] Other examples of the repeating unit represented by formula (4) include the repeating units described in paragraphs

[0094] to

[0105] of JP 2014-041327 A and the repeating unit described in paragraph

[0094] of WO 2018 / 193954 A.

[0159] The content of the repeating unit having a photoacid generating group is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total repeating units in the resin (A), and the upper limit thereof is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less.

[0160] <Repeating unit represented by formula (V-1) or the following formula (V-2)> The resin (A) may have a repeating unit represented by the following formula (V-1) or the following formula (V-2). The repeating units represented by the following formula (V-1) and the following formula (V-2) are preferably repeating units different from the above-mentioned repeating units.

[0161]

[0162] In the formula, R ６ and R ７each independently represents a hydrogen atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an acyloxy group, a cyano group, a nitro group, an amino group, a halogen atom, an ester group (-OCOR or -COOR: R is an alkyl group or a fluorinated alkyl group having 1 to 6 carbon atoms), or a carboxyl group. The alkyl group is preferably a linear or branched alkyl group having 1 to 10 carbon atoms. The cycloalkyl group may be monocyclic or polycyclic, and is preferably a cycloalkyl group having 3 to 10 carbon atoms. n ３ represents an integer of 0 to 6. ４ represents an integer of 0 to 4. ４ is a methylene group, an oxygen atom, or a sulfur atom. Examples of repeating units represented by formula (V-1) or (V-2) are shown below. Examples of repeating units represented by formula (V-1) or (V-2) include the repeating units described in paragraph

[0100] of WO 2018 / 193954.

[0163] Resin (A) may also use the "repeating units for reducing the mobility of the main chain" described in paragraphs

[0292] to

[0308] of WO 2023 / 106171.

[0164] <Repeating Unit Having Alicyclic Hydrocarbon Structure and Not Exhibiting Acid Decomposability> The resin (A) may have a repeating unit having an alicyclic hydrocarbon structure and not exhibiting acid decomposability. Examples of such repeating units include repeating units derived from 1-adamantyl (meth)acrylate, diamantyl (meth)acrylate, tricyclodecanyl (meth)acrylate, or cyclohexyl (meth)acrylate.

[0165] In addition, the alicyclic hydrocarbon structure is preferably substituted with a hydroxyl group or a cyano group, in order to improve substrate adhesion and developer affinity. Specific examples of repeating units having an alicyclic hydrocarbon structure having a hydroxyl group or a cyano group include those described in paragraphs

[0081] to

[0084] of JP 2014-098921 A.

[0166] <Other Repeating Units> Furthermore, the resin (A) may have a repeating unit other than the repeating units described above. For example, the resin (A) may have a repeating unit selected from the group consisting of a repeating unit having an oxathiane ring group, a repeating unit having an oxazolone ring group, a repeating unit having a dioxane ring group, and a repeating unit having a hydantoin ring group. Examples of such repeating units are shown below.

[0167]

[0168] In addition to the repeating structural units described above, the resin (A) may have various repeating structural units for the purpose of adjusting dry etching resistance, suitability for a standard developer, substrate adhesion, resist profile, resolution, heat resistance, sensitivity, and the like.

[0169] Resin (A) can be synthesized according to a conventional method (e.g., radical polymerization). The weight average molecular weight of resin (A), as measured by GPC in terms of polystyrene, is preferably 30,000 or less, more preferably 1,000 to 30,000, even more preferably 3,000 to 30,000, and particularly preferably 5,000 to 15,000. The dispersity (molecular weight distribution) of resin (A) is preferably 1 to 5, more preferably 1 to 3, even more preferably 1.2 to 3.0, and particularly preferably 1.2 to 2.0. The smaller the dispersity, the better the resolution and resist shape, and furthermore, the smoother the sidewalls of the resist pattern and the better the roughness.

[0170] In the resist composition, the lower limit of the content of resin (A) is preferably 35.0 mass% or more, more preferably 40.0 mass% or more, and even more preferably 45.0 mass% or more, based on the total solid content of the resist composition. The upper limit of the content of resin (A) is preferably 99.9 mass% or less, more preferably 90.0 mass% or less, and even more preferably 80.0 mass% or less, based on the total solid content of the resist composition. Resin (A) may be used alone, or two or more types may be used in combination. Resin (A) may be used alone, or two or more types may be used. When two or more types are used, it is preferable that the total content is within the above-mentioned suitable content range.

[0171] [Boron-Containing Compound (C)] The resist composition contains a boron-containing compound (C). The boron-containing compound (C) is not particularly limited as long as it contains a boron atom. However, compounds having a borate anion (salt compounds) are more preferred because they provide superior effects of the present invention. Among compounds having a borate anion, onium salt compounds are preferred, and sulfonium salt compounds, iodonium salt compounds, quaternary ammonium salt compounds, or quaternary phosphonium salt compounds are more preferred. The compound having a borate anion may be either a low-molecular-weight compound or a high-molecular-weight compound, but low-molecular-weight compounds are preferred. The molecular weight of the compound having a borate anion is preferably 1,200 or less, more preferably 1,000 or less, and even more preferably 800 or less. While there is no particular lower limit, a molecular weight of 400 or more is preferred. Among compounds having a borate anion, compounds represented by the following general formula (1C) are more preferred.

[0172] <Compound represented by the following general formula (1C)>

[0173]

[0174] In general formula (1C), R １Ｃ ~R ４Ｃ Each of Y independently represents a substituent. ＋ represents an organic cation or an inorganic cation. m represents an integer of 1 or more. When m represents an integer of 2 or more, a plurality of R １ｃ When m is an integer of 2 or more, a plurality of R ２ｃ When m is an integer of 2 or more, a plurality of R ３ｃ When m is an integer of 2 or more, a plurality of R ４ｃ When m is an integer of 2 or more, a plurality of Y ＋ may be the same or different.

[0175] In general formula (1C), R １Ｃ ~R ４ＣR each independently represents a substituent. １Ｃ ~R ４Ｃ The substituent represented by the formula (I) is not particularly limited, and examples thereof include the groups exemplified as the substituent T above.

[0176] R １Ｃ ~R ４Ｃ Examples of the substituent represented by the formula (I) include an alkyl group, an aryl group, a heteroaryl group, an aryloxy group, a halogen atom (preferably a fluorine atom), a hydroxyl group, and a cyano group. The alkyl group may be either linear or branched. The number of carbon atoms in the alkyl group is, for example, preferably 1 to 20, and more preferably 1 to 15. Preferred examples of the alkyl group include linear alkyl groups having 1 to 15 carbon atoms and branched alkyl groups having 3 to 15 carbon atoms. The aryl group and the heteroaryl group may be either monocyclic or polycyclic. The number of carbon atoms in the aryl group is, for example, preferably 6 to 20, and more preferably 6 to 10. Specific examples of the aryl group include a phenyl group or a naphthyl group, and more preferably a phenyl group. The type of heteroatom contained in the heteroaryl group is not particularly limited, and examples include an oxygen atom, a nitrogen atom, and a sulfur atom. The number of carbon atoms in the heteroaryl group is, for example, preferably 3 to 15, and more preferably 3 to 10. Specific examples of the ring constituting the heteroaryl group include a pyrrole ring, a furan ring, a thiophene ring, an indole ring, a benzofuran ring, and a benzothiophene ring.

[0177] The aryl group in the aryloxy group is the same as the above-mentioned aryl group, and the preferred range is also the same.

[0178] The alkyl group, aryl group, heteroaryl group, and aryloxy group may have a substituent. The substituent that the alkyl group, aryl group, heteroaryl group, and aryloxy group may have is not particularly limited, and examples thereof include the groups exemplified above as the substituent T. Examples of the substituent include alkyl groups (e.g., linear alkyl groups having 1 to 15 carbon atoms and branched alkyl groups having 3 to 15 carbon atoms), cycloalkyl groups (e.g., cyclic alkyl groups having 3 to 15 carbon atoms), aryl groups (which may be either monocyclic or polycyclic, preferably having 6 to 20 carbon atoms, more preferably having 6 to 10 carbon atoms), heteroaryl groups (which may be either monocyclic or polycyclic, preferably having 3 to 15 carbon atoms, more preferably having 3 to 10 carbon atoms), alkoxy groups (e.g., linear alkoxy groups having 1 to 15 carbon atoms, branched alkoxy groups having 1 to 15 carbon atoms), cycloalkoxy groups (e.g., cyclic alkoxy groups having 3 to 15 carbon atoms), halogen atoms (e.g., fluorine atoms, chlorine atoms, iodine atoms), hydroxyl groups, cyano groups, and nitro groups. The substituents may further have other substituents. For example, the alkyl groups may have halogen atoms as substituents to form halogenated alkyl groups such as trifluoromethyl groups.

[0179] In addition, R １Ｃ ~R ４Ｃ Among these, adjacent ones may be bonded to each other to form a ring. The ring formed by bonding adjacent ones to each other is not particularly limited and may be either a monocycle or a polycycle. The ring may contain heteroatoms such as oxygen atoms, nitrogen atoms, and sulfur atoms, and / or carbonyl carbon as ring member atoms. In addition, the ring may be either an aromatic ring or an alicyclic ring.

[0180] Y ＋ represents an organic cation or an inorganic cation. m represents an integer of 1 or more. m is not particularly limited as long as it is an integer of 1 or more, and is, for example, preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. When m represents an integer of 2 or more, a plurality of Y ＋may be bonded via a linking group or without a linking group.

[0181] Y ＋ The organic cation represented by the formula (ZaI) is not particularly limited, and examples thereof include quaternary ammonium cations and quaternary phosphonium cations such as an organic cation represented by the formula (ZaI) below (cation (ZaI)), an organic cation represented by the formula (ZaII) below (cation (ZaII)), an organic cation represented by the formula (ZaIII) below (cation (ZaIII)), and an organic cation represented by the formula (ZaIV) below (cation (ZaIV)).

[0182]

[0183] In the formula (ZaI), R ２０１ ~R ２０３ R each independently represents an organic group. ２０１ ~R ２０３ The number of carbon atoms in the organic group represented by R is preferably 1 to 30, and more preferably 1 to 20. ２０１ ~R ２０３ Two of the organic groups represented by the formula (I) may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester group, an amide group, or a carbonyl group. ２０１ ~R ２０３ Examples of the group formed by bonding two of the organic groups represented by the formula (I) include an alkylene group (e.g., a butylene group and a pentylene group), and —CH ２ -CH ２ -O-CH ２ -CH ２ - are listed.

[0184] Of the above-mentioned cations (ZaI), cations (ZaI-1), (ZaI-2), organic cations represented by formula (ZaI-3b) (cations (ZaI-3b)), or organic cations represented by formula (ZaI-4b) (cations (ZaI-4b)) are preferred.

[0185] First, the cation (ZaI-1) will be described. In the cation (ZaI-1), R ２０１ ~R ２０３At least one of R represents a monovalent aromatic ring group which may have a substituent. ２０１ ~R ２０３ may all be monovalent aromatic ring groups, or R ２０１ ~R ２０３ A part of R may be a monovalent aromatic ring group, and the rest may be an alkyl group or a cycloalkyl group which may have a substituent. ２０１ ~R ２０３ one of which is a monovalent aromatic ring group, and R ２０１ ~R ２０３ The remaining two of R may be bonded to form a ring structure, and the formed ring may contain an oxygen atom, a sulfur atom, an ester group, an amide group, or a carbonyl group. ２０１ ~R ２０３ Examples of the group formed by combining two of the above include an alkylene group in which one or more methylene groups may be substituted with an oxygen atom, a sulfur atom, an ester group, an amide group, and / or a carbonyl group (e.g., a butylene group, a pentylene group, or a -CH ２ -CH ２ -O-CH ２ -CH ２ -) are listed.

[0186] In the cation (ZaI-1), examples of the monovalent aromatic ring group include an aryl group and a heteroaryl group. The aryl group and the heteroaryl group may be either monocyclic or polycyclic. The number of carbon atoms in the aryl group is, for example, preferably 6 to 20, more preferably 6 to 10. Specific examples of the aryl group are preferably a phenyl group or a naphthyl group, more preferably a phenyl group. The type of heteroatom contained in the heteroaryl group is not particularly limited, and examples include an oxygen atom, a nitrogen atom, and a sulfur atom. The number of carbon atoms in the heteroaryl group is, for example, preferably 3 to 15, more preferably 3 to 10. Specific examples of the ring constituting the heteroaryl group include a pyrrole ring, a furan ring, a thiophene ring, an indole ring, a benzofuran ring, and a benzothiophene ring. In the cation (ZaI-1), R ２０１ ~R ２０３When two or more of the above are monovalent aromatic ring groups, the two or more monovalent aromatic ring groups may be the same or different.

[0187] In the cation (ZaI-1), the alkyl group is preferably a linear alkyl group having 1 to 15 carbon atoms or a branched alkyl group having 3 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, and a t-butyl group. The cycloalkyl group may be either monocyclic or polycyclic, and is preferably a cycloalkyl group having 3 to 15 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

[0188] R ２０１ ~R ２０３ The monovalent aromatic ring group, alkyl group, and cycloalkyl group may each independently have a substituent, such as an alkyl group (e.g., a linear alkyl group having 1 to 15 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, etc.), a cycloalkyl group (e.g., a cycloalkyl group having 3 to 15 carbon atoms, etc.), an aryl group (which may be either a monocyclic or polycyclic group. The number of carbon atoms is preferably 6 to 20, and more preferably 6 to 10), a heteroaryl group (which may be either a monocyclic or polycyclic group. The number of carbon atoms is preferably 3 to 15, and more preferably 3 to 10), an alkoxy group (e.g., a linear alkoxy group having 1 to 15 carbon atoms, a branched alkoxy group having 1 to 15 carbon atoms), a cycloalkoxy group (which may be either a monocyclic or polycyclic group. The number of carbon atoms is preferably 3 to 15, and more preferably 3 to 10), a halogen atom (e.g., a fluorine atom, a chlorine atom, an iodine atom, etc.), a hydroxyl group, a cyano group, and a nitro group. The above substituents may further have other substituents. For example, the above alkyl groups may have a halogen atom as a substituent to form halogenated alkyl groups such as trifluoromethyl groups.

[0189] Examples of the cation (ZaI-1) include an optionally substituted triarylsulfonium cation, an optionally substituted diarylalkylsulfonium cation, and an optionally substituted aryldialkylsulfonium cation. Among these, an optionally substituted triarylsulfonium cation is preferred in terms of achieving the effects of the present invention more excellently.

[0190] Next, the cation (ZaI-2) will be described. In the cation (ZaI-2), R ２０１ ~R ２０３ Each of R independently represents an organic group that does not have an aromatic ring. ２０１ ~R ２０３ The organic group having no aromatic ring represented by the formula (I) generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. ２０１ ~R ２０３ The organic group having no aromatic ring represented by the formula (I) is preferably an alkyl group, a cycloalkyl group, an allyl group, a vinyl group, a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or an alkoxycarbonylmethyl group, and more preferably a linear or branched 2-oxoalkyl group.

[0191] In the cation (ZaI-2), examples of the alkyl group include a linear alkyl group having 1 to 15 carbon atoms (preferably 1 to 10 carbon atoms) and a branched alkyl group having 3 to 15 carbon atoms (preferably 3 to 10 carbon atoms). The cycloalkyl group may be either monocyclic or polycyclic, and is preferably a cycloalkyl group having 3 to 15 carbon atoms (preferably 3 to 10 carbon atoms). In the cation (ZaI-2), the number of carbon atoms in the linear or branched 2-oxoalkyl group is, for example, preferably 2 to 15, more preferably 2 to 10. In the cation (ZaI-2), the number of carbon atoms in the 2-oxocycloalkyl group is, for example, preferably 4 to 15, more preferably 4 to 10. In the cation (ZaI-2), the number of carbon atoms in the alkoxycarbonylmethyl group is, for example, preferably 3 to 15, more preferably 3 to 10. Note that, in the case of R ２０１ ~R ２０３Each of the above groups represented by the formula (I) may further have a substituent, such as a halogen atom, an alkoxy group (e.g., having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

[0192] Next, the cation (ZaI-3b) will be described.

[0193]

[0194] In formula (ZaI-3b), R １ｃ ~R ５ｃ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a monovalent aromatic ring group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitro group, an alkylthio group, or an arylthio group.

[0195] R １ｃ ~R ５ｃ The alkyl group represented by the formula (I) is preferably a linear alkyl group having 1 to 15 carbon atoms or a branched alkyl group having 3 to 15 carbon atoms. The cycloalkyl group may be either monocyclic or polycyclic, and is preferably a cycloalkyl group having 3 to 15 carbon atoms (preferably 3 to 10 carbon atoms). The alkyl group and cycloalkyl group may further have a substituent. Examples of the substituent include a halogen atom, an alkoxy group (e.g., having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, and a nitro group.

[0196] R １ｃ ~R ５ｃ The alkyl group moiety in the alkoxy group, alkoxycarbonyloxy group, and alkylthio group represented by the formula (I) is preferably a linear alkyl group having 1 to 15 carbon atoms or a branched alkyl group having 3 to 15 carbon atoms. １ｃ ~R ５ｃ The alkyl group moiety in the alkoxy group, alkoxycarbonyloxy group, and alkylthio group represented by the formula (I) may further have a substituent, such as a halogen atom, an alkoxy group (e.g., having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

[0197] R １ｃ ~R ５ｃExamples of the monovalent aromatic ring group represented by the formula (I) include an aryl group and a heteroaryl group. The aryl group and the heteroaryl group may be either monocyclic or polycyclic. The number of carbon atoms in the aryl group is, for example, preferably 6 to 20, and more preferably 6 to 10. Specific examples of the aryl group include a phenyl group or a naphthyl group, and more preferably a phenyl group. The type of heteroatom contained in the heteroaryl group is not particularly limited, and examples include an oxygen atom, a nitrogen atom, and a sulfur atom. The number of carbon atoms in the heteroaryl group is, for example, preferably 3 to 15, and more preferably 3 to 10. Specific examples of the ring constituting the heteroaryl group include a pyrrole ring, a furan ring, a thiophene ring, an indole ring, a benzofuran ring, and a benzothiophene ring. The substituent that the aryl group and the heteroaryl group may have is not particularly limited, and examples thereof include the groups exemplified above as the substituent T. Examples of the substituent include alkyl groups (e.g., linear alkyl groups having 1 to 15 carbon atoms, branched alkyl groups having 3 to 15 carbon atoms, etc.), cycloalkyl groups (which may be either monocyclic or polycyclic, for example, cycloalkyl groups having 3 to 15 carbon atoms, etc.), aryl groups (which may be either monocyclic or polycyclic, preferably having 6 to 20 carbon atoms, more preferably 6 to 10 carbon atoms), heteroaryl groups (which may be either monocyclic or polycyclic, preferably having 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms), alkoxy groups (e.g., linear alkoxy groups having 1 to 15 carbon atoms, branched alkoxy groups having 1 to 15 carbon atoms, etc.), cycloalkoxy groups (which may be either monocyclic or polycyclic, such as cycloalkoxy groups having 3 to 15 carbon atoms), halogen atoms (e.g., fluorine atoms, chlorine atoms, iodine atoms, etc.), hydroxyl groups, cyano groups, and nitro groups. The substituents may further have other substituents. For example, the alkyl groups may have halogen atoms as substituents, forming halogenated alkyl groups such as trifluoromethyl groups.

[0198] R １ｃ ~R ５ｃEach aryl group moiety in the aryloxy group and arylthio group represented by the formula (I) may be either a monocyclic or polycyclic ring. The number of carbon atoms in the aryl group moiety is, for example, preferably 6 to 20, more preferably 6 to 10. Specific examples of the aryl group moiety include a phenyl group or a naphthyl group, and more preferably a phenyl group. R １ｃ ~R ５ｃ The aryl group moiety of the aryloxy group and arylthio group represented by the following formula may further have a substituent. １ｃ ~R ５ｃ The same substituents as those which the monovalent aromatic ring group represented by the following formula (I) may have are listed, and the preferred embodiments are also the same.

[0199] In formula (ZaI-3b), R ６ｃ and R ７ｃ R each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group, or an aryl group. ６ｃ and R ７ｃ Examples of the alkyl group represented by the formula (ZaI-3b) include R １ｃ ~R ５ｃ The meaning and preferred embodiments are the same as those of the alkyl group represented by the formula R ６ｃ and R ７ｃ Examples of the cycloalkyl group represented by the formula (ZaI-3b) include R １ｃ ~R ５ｃ The meaning and preferred embodiments are also the same as those of the cycloalkyl group represented by R ６ｃ and R ７ｃ The aryl group represented by the formula (ZaI-3b) includes R １ｃ ~R ５ｃ The meaning and preferred embodiments are also the same as those of the aryl group represented by the following formula:

[0200] In formula (ZaI-3b), R ｘ and R ｙ R each independently represents an alkyl group, a cycloalkyl group, a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group, or a vinyl group. ｘ and R ｙ Examples of the alkyl group represented by the formula (ZaI-3b) include R１ｃ ~R ５ｃ The meaning and preferred embodiments are the same as those of the alkyl group represented by the formula R ｘ and R ｙ Examples of the cycloalkyl group represented by the formula (ZaI-3b) include R １ｃ ~R ５ｃ The meaning and preferred embodiments are also the same as those of the cycloalkyl group represented by R ｘ and R ｙ The number of carbon atoms in the linear or branched 2-oxoalkyl group represented by R is, for example, preferably 2 to 15, and more preferably 2 to 10. ｘ and R ｙ The number of carbon atoms in the 2-oxocycloalkyl group represented by R is preferably 4 to 15, and more preferably 4 to 10. ｘ and R ｙ The number of carbon atoms in the alkoxycarbonylmethyl group represented by the formula (I) is preferably 3 to 15, more preferably 3 to 10. ｘ and R ｙ Each of the above groups represented by the formula (I) may further have a substituent, such as a halogen atom, an alkoxy group (e.g., having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

[0201] In formula (ZaI-3b), R １ｃ ~R ５ｃ Two or more of the following, R ５ｃ and R ６ｃ , R ６ｃ and R ７ｃ , R ５ｃ and R ｘ , and R ｘ and R ｙ may be bonded to each other to form a ring, and the formed rings may each independently contain an oxygen atom, a sulfur atom, a ketone group, an ester group, or an amide bond. Examples of the ring include an aromatic or non-aromatic monocyclic (preferably a 3- to 10-membered ring, more preferably a 4- to 8-membered ring, and even more preferably a 5- or 6-membered ring) hydrocarbon ring, an aromatic or non-aromatic monocyclic (preferably a 3- to 10-membered ring, more preferably a 4- to 8-membered ring, and even more preferably a 5- or 6-membered ring) heterocycle, and a polycyclic fused ring formed by combining two or more of these monocyclic rings.

[0202] R １ｃ ~R ５ｃ Two or more of the following, R ６ｃ and R ７ｃ , and R ｘ and R ｙ Examples of the group formed by bonding of R include alkylene groups such as butylene and pentylene. The methylene group in this alkylene group may be substituted with a heteroatom such as an oxygen atom. ５ｃ and R ６ｃ , and R ５ｃ and R ｘ The group formed by bonding is preferably a single bond or an alkylene group. Examples of the alkylene group include a methylene group and an ethylene group.

[0203] Next, the cation (ZaI-4b) will be described.

[0204]

[0205] In formula (ZaI-4b), l represents an integer of 0 to 2, and r represents an integer of 0 to 8. １３ represents a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, or an alkoxycarbonyl group. １３ The alkyl group represented by the formula (I) is preferably a linear alkyl group having 1 to 15 carbon atoms or a branched alkyl group having 3 to 15 carbon atoms. １３ The cycloalkyl group represented by the formula (I) may be either monocyclic or polycyclic, and is preferably a cycloalkyl group having 3 to 15 carbon atoms. The alkyl group and cycloalkyl group may further have a substituent. Examples of the substituent include a halogen atom, an alkoxy group (e.g., having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, and a nitro group.

[0206] R １３ The alkyl group moiety in the alkoxy group and alkoxycarbonyl group represented by the formula (I) is preferably a linear alkyl group having 1 to 15 carbon atoms or a branched alkyl group having 3 to 15 carbon atoms. １３Each alkyl group in the alkoxy group and alkoxycarbonyl group represented by the formula (I) may further have a substituent, which may include a halogen atom, an alkoxy group (e.g., having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, and a nitro group.

[0207] R １４ represents a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, or an alkylsulfonyl group. １４ The alkyl group represented by the formula (I) is preferably a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms. １４ The cycloalkyl group represented by the formula (R) may be either a monocyclic or polycyclic group, and is preferably a cycloalkyl group having 3 to 15 carbon atoms. The alkyl group and cycloalkyl group may further have a substituent. Examples of the substituent include a halogen atom, an alkoxy group (e.g., having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, and a nitro group. １４ The alkyl group moiety in the alkoxy group, alkoxycarbonyl group, alkylcarbonyl group, and alkylsulfonyl group represented by the formula (I) is preferably a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms. １４ Each alkyl group moiety in the alkoxy group, alkoxycarbonyl group, alkylcarbonyl group, and alkylsulfonyl group represented by the formula (I) may further have a substituent, such as a halogen atom, an alkoxy group (e.g., having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

[0208] R １５ R each independently represents an alkyl group, a cycloalkyl group, or a naphthyl group. １５ The alkyl group represented by R may be either linear or branched. The number of carbon atoms in the alkyl group is preferably 1 to 10. The alkyl group is preferably a methyl group, an ethyl group, an n-butyl group, or a t-butyl group. １５ The cycloalkyl group represented by the formula (I) may be either a monocyclic or polycyclic group, and is preferably a cycloalkyl group having 3 to 15 carbon atoms. １５The alkyl group, cycloalkyl group, and naphthyl group represented by the formula (I) may further have a substituent. The substituent is not particularly limited, and examples thereof include the groups exemplified above as the substituent T. １５ may be bonded to each other to form a ring. １５ When two R are bonded to each other to form a ring, the ring skeleton may contain a heteroatom such as an oxygen atom or a nitrogen atom. １５ are preferably alkylene groups and are bonded to each other to form an aliphatic hydrocarbon ring structure.

[0209] Next, the cation (ZaII) will be described. In formula (ZaII), R ２０４ and R ２０５ each independently represents a monovalent aromatic ring group which may have a substituent, an alkyl group which may have a substituent, or a cycloalkyl group which may have a substituent, and a monovalent aromatic ring group is preferred in that the effects of the present invention are more excellent.

[0210] R ２０４ and R ２０５ Examples of the monovalent aromatic ring group include an aryl group and a heteroaryl group. The aryl group is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The heteroaryl group has a heteroatom such as an oxygen atom, a nitrogen atom, or a sulfur atom. Examples of the ring constituting the heteroaryl group include a pyrrole ring, a furan ring, a thiophene ring, an indole ring, a benzofuran ring, and a benzothiophene ring. R ２０４ and R ２０５ The alkyl group in R is preferably a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group). ２０４ and R ２０５ The cycloalkyl group may be either monocyclic or polycyclic, and is preferably a cycloalkyl group having 3 to 10 carbon atoms (for example, a cyclopentyl group, a cyclohexyl group, and a norbornyl group).

[0211] R ２０４ and R ２０５The monovalent aromatic ring group, alkyl group, and cycloalkyl group may further have another substituent, and examples of the other substituent include an alkyl group (e.g., having 1 to 15 carbon atoms), a monovalent aromatic ring group (e.g., having 6 to 15 carbon atoms), an alkoxy group (e.g., having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group.

[0212] In formula (ZaII), R ２０４ and R ２０５ Preferably, each independently represents an optionally substituted monovalent aromatic ring group or an optionally substituted alkyl group, and a monovalent aromatic ring group is preferred in terms of achieving better effects of the present invention. As the cation (ZaII), for example, an optionally substituted diaryl iodonium cation is preferred.

[0213] Next, the cation (ZaIII) will be described. The cation (ZaIII) corresponds to a quaternary ammonium cation or a quaternary phosphonium cation.

[0214]

[0215] In formula (ZaIII), X ３０１ represents a nitrogen atom or a phosphorus atom. ３０１ ~R ３０４ Each independently represents a monovalent aromatic ring group which may have a substituent, an alkyl group which may have a substituent, or a cycloalkyl group which may have a substituent. ３０１ The nitrogen atom or phosphorus atom represented by the formula: is cationized.

[0216] R ３０１ ~R ３０４ The alkyl group represented by the formula (I) may be either linear or branched, but linear is more preferred. The number of carbon atoms in the alkyl group is preferably 1 to 20, more preferably 4 to 18, and even more preferably 6 to 12. The substituent that the alkyl group may have is not particularly limited, and examples thereof include the groups exemplified for the substituent T above. R ３０１ ~R ３０４The cycloalkyl group represented by the formula (I) may be either monocyclic or polycyclic. The number of carbon atoms in the cycloalkyl group is preferably 3 to 20, more preferably 4 to 18, and even more preferably 6 to 12. The substituent that the cycloalkyl group may have is not particularly limited, and examples thereof include the groups exemplified above for the substituent T.

[0217] R ３０１ ~R ３０４Examples of the monovalent aromatic ring group represented by the formula (I) include an aryl group and a heteroaryl group. The aryl group and the heteroaryl group may be either monocyclic or polycyclic. The number of carbon atoms in the aryl group is, for example, preferably 6 to 20, and more preferably 6 to 10. Specific examples of the aryl group include a phenyl group or a naphthyl group, and more preferably a phenyl group. The type of heteroatom contained in the heteroaryl group is not particularly limited, and examples include an oxygen atom, a nitrogen atom, and a sulfur atom. The number of carbon atoms in the heteroaryl group is, for example, preferably 3 to 15, and more preferably 3 to 10. Specific examples of the ring constituting the heteroaryl group include a pyrrole ring, a furan ring, a thiophene ring, an indole ring, a benzofuran ring, and a benzothiophene ring. The substituent that the aryl group and the heteroaryl group may have is not particularly limited, and examples thereof include the groups exemplified above as the substituent T. Examples of the substituent include alkyl groups (e.g., linear alkyl groups having 1 to 15 carbon atoms, branched alkyl groups having 3 to 15 carbon atoms, etc.), cycloalkyl groups (which may be either monocyclic or polycyclic, for example, a cycloalkyl group having 3 to 15 carbon atoms, etc.), aryl groups (which may be either monocyclic or polycyclic, preferably having 6 to 20 carbon atoms, more preferably 6 to 10 carbon atoms), heteroaryl groups (which may be either monocyclic or polycyclic, preferably having 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms), alkoxy groups (e.g., linear alkoxy groups having 1 to 15 carbon atoms, branched alkoxy groups having 1 to 15 carbon atoms, etc.), cycloalkoxy groups (which may be either monocyclic or polycyclic, for example, a cycloalkoxy group having 3 to 15 carbon atoms, etc.), halogen atoms (e.g., fluorine atom, chlorine atom, iodine atom, etc.), hydroxyl groups, cyano groups, nitro groups, etc. The above substituents may further have other substituents. For example, the above alkyl groups may have a halogen atom as a substituent to form halogenated alkyl groups such as trifluoromethyl groups.

[0218] In formula (ZaIII), R ３０１ ~R ３０４may be bonded to each other to form an alicyclic ring. The alicyclic ring may have, as ring member atoms, X as specified in the formula. ３０１ The alicyclic ring may contain a heteroatom other than the nitrogen atom or phosphorus atom (for example, an oxygen atom, a nitrogen atom, an oxygen atom, etc.). Furthermore, a ring member atom may be substituted with a carbonyl carbon (>C=O). The alicyclic ring may be monocyclic or polycyclic. The number of ring member atoms of the alicyclic ring is preferably 5 to 15, more preferably 5 to 10, and even more preferably 5 or 6. The alicyclic ring may further have a substituent. Examples of the substituent include the groups exemplified as the substituent T above.

[0219] Next, the cation (ZaIV) will be described. The cation (ZaIV) corresponds to a quaternary ammonium cation or a quaternary phosphonium cation.

[0220]

[0221] In formula (ZaIV), X ３０２ represents a nitrogen atom or a phosphorus atom. ３０５ represents an alkyl group which may have a substituent or a cycloalkyl group which may have a substituent; W ３０１ has X as a ring member atom ３０２ The cation (ZaIV) represents an aromatic ring containing a nitrogen atom or a phosphorus atom represented by the formula: ３０２ The nitrogen atom or phosphorus atom represented by the formula: is cationized.

[0222] R ３０５ Examples of the alkyl group which may have a substituent represented by the formula (ZaIII) include R ３０１ ~R ３０４ The meaning and preferred embodiments are the same as those of the alkyl group optionally having a substituent represented by the following formula: ３０５ Examples of the cycloalkyl group which may have a substituent represented by the formula (ZaIII) include R ３０１ ~R ３０４ The meaning and preferred embodiments are also the same as those of the cycloalkyl group optionally having a substituent represented by the following formula: ３０１ The aromatic ring represented by the formula (I) may be either a monocyclic ring or a polycyclic ring.３０１ The aromatic ring represented by the formula may contain, as a ring member atom, a heteroatom other than the nitrogen atom or phosphorus atom specified in the formula (for example, an oxygen atom, a nitrogen atom, an oxygen atom, etc.). ３０１ The number of ring atoms in the aromatic ring represented by the formula (I) is preferably 5 to 15, more preferably 5 to 10, and even more preferably 5 or 6. ３０１ The aromatic ring represented by the formula (I) may further have a substituent. Examples of the substituent include the groups exemplified as the substituent T above. Examples of the substituent include alkyl groups (e.g., linear alkyl groups having 1 to 15 carbon atoms, branched alkyl groups having 3 to 15 carbon atoms, etc.), cycloalkyl groups (which may be either monocyclic or polycyclic, for example, a cycloalkyl group having 3 to 15 carbon atoms), aryl groups (which may be either monocyclic or polycyclic, preferably having 6 to 20 carbon atoms, more preferably 6 to 10 carbon atoms), heteroaryl groups (which may be either monocyclic or polycyclic, preferably having 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms), alkoxy groups (e.g., linear alkoxy groups having 1 to 15 carbon atoms, branched alkoxy groups having 1 to 15 carbon atoms), cycloalkoxy groups (which may be either monocyclic or polycyclic, for example, a cycloalkoxy group having 3 to 15 carbon atoms), halogen atoms (e.g., fluorine atoms, chlorine atoms, iodine atoms, etc.), hydroxyl groups, cyano groups, nitro groups, etc. Specific examples of the aromatic ring include a pyridinium cation.

[0223] In general formula (1C), Y ＋ The inorganic cation represented by the formula (I) is not particularly limited, and examples thereof include alkali metal ions such as lithium ion, potassium ion, sodium ion, rubidium ion, and cesium ion, and alkaline earth metal ions such as magnesium ion and calcium ion.

[0224] In general formula (1C), Y ＋ As the cation, an organic cation is preferred, a sulfonium cation or an iodonium cation is more preferred, the above-mentioned cation (ZaI) or cation (ZaII) is further preferred, and a triarylsulfonium cation or a diaryliodonium cation is particularly preferred.

[0225] The boron-containing compound (C) is also preferably a compound in which the atom at the bonding position to the boron atom in the atomic group bonding to the boron atom is selected from a carbon atom, an oxygen atom, or a nitrogen atom, in terms of the effects of the present invention being more excellent.

[0226] The boron-containing compound (C) is preferably a compound represented by the following general formula (2C).

[0227]

[0228] In general formula (2C), R ５ｃ ~R ８ｃ each independently represents an alkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group. ＋ represents an organic cation or an inorganic cation. m represents an integer of 1 or more. When m represents an integer of 2 or more, a plurality of R ５ｃ When m is an integer of 2 or more, a plurality of R ６ｃ When m is an integer of 2 or more, a plurality of R ７ｃ When m is an integer of 2 or more, a plurality of R ８ｃ When m is an integer of 2 or more, a plurality of Y ＋ may be the same or different.

[0229] In general formula (2C), R ５ｃ ~R ８ｃ R each independently represents an alkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group. ５ｃ ~R ８ｃThe alkyl group represented by may be either linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 15, and more preferably 1 to 10. For example, when the alkyl group is a linear alkyl group, the number of carbon atoms in the alkyl group is preferably 1 to 15, and when the alkyl group is a branched alkyl group, the number of carbon atoms in the alkyl group is preferably 3 to 15. Specific examples of the alkyl group include a methyl group, an isopropyl group, and a t-butyl group. R ５ｃ ~R ８ｃ The cycloalkyl group represented by may be either monocyclic or polycyclic. The number of carbon atoms in the cycloalkyl group is preferably, for example, 3 to 15. A specific example of the cycloalkyl group is preferably a cyclohexyl group.

[0230] R ５ｃ ~R ８ｃ The aryl group and heteroaryl group represented by may be either monocyclic or polycyclic. The number of carbon atoms in the aryl group is, for example, preferably 6 to 20, and more preferably 6 to 10. Specific examples of the aryl group include a phenyl group or a naphthyl group, and more preferably a phenyl group. The type of heteroatom contained in the heteroaryl group is not particularly limited, and examples include an oxygen atom, a nitrogen atom, and a sulfur atom. The number of carbon atoms in the heteroaryl group is, for example, preferably 3 to 15, and more preferably 3 to 10. Specific examples of the ring constituting the heteroaryl group include a pyrrole ring, a furan ring, a thiophene ring, an indole ring, a benzofuran ring, and a benzothiophene ring.

[0231] The alkyl group, cycloalkyl group, aryl group, and heteroaryl group may have a substituent. The substituent that the alkyl group, aryl group, and heteroaryl group may have is not particularly limited, and examples thereof include the groups exemplified above as the substituent T.

[0232] Y in general formula (2C) ＋ , and m is Y in general formula (1C). ＋ , and m, and preferred examples thereof are also the same.

[0233] The boron-containing compound (C) is more preferably a compound represented by the following general formula (3C).

[0234]

[0235] In general formula (3C), R ９ｃ ~R １３ｃ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, or a halogen atom. ＋ represents an organic cation or an inorganic cation. m represents an integer of 1 or more. ９ｃ may be the same or different. １０ｃ may be the same or different. １１ｃ may be the same or different. １２ｃ may be the same or different. １３ｃ When m is an integer of 2 or more, a plurality of Y ＋ may be the same or different.

[0236] R ９ｃ ~R １３ｃ The alkyl group represented by may be either linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 15, and more preferably 1 to 10. For example, when the alkyl group is a linear alkyl group, the number of carbon atoms in the alkyl group is preferably 1 to 15, and when the alkyl group is a branched alkyl group, the number of carbon atoms in the alkyl group is preferably 3 to 15. Specific examples of the alkyl group that are preferred are a methyl group, an isopropyl group, and a t-butyl group.

[0237] R ９ｃ ~R １３ｃ The cycloalkyl group represented by may be either monocyclic or polycyclic. The number of carbon atoms in the cycloalkyl group is preferably, for example, 3 to 15. A specific example of the cycloalkyl group is preferably a cyclohexyl group.

[0238] R ９ｃ ~R １３ｃThe alkoxy group represented by may be either linear or branched. The alkyl group in the alkoxy group may be any of the alkyl groups represented by the above-mentioned R ９ｃ ~R １３ｃ Examples of the alkyl group include those represented by the following formula:

[0239] R ９ｃ ~R １３ｃ Examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0240] The alkyl group, cycloalkyl group, and alkoxy group may have a substituent. The substituent that the alkyl group and alkoxy group may have is not particularly limited, and examples thereof include the groups exemplified above as the substituent T.

[0241] Y in general formula (3C) ＋ , and m is Y in general formula (1C). ＋ , and m, and preferred examples thereof are also the same.

[0242] The boron-containing compound (C) preferably contains at least one of a fluorine atom and an iodine atom, in that the effects of the present invention are more excellent.

[0243] Specific examples of the boron-containing compound (C) are listed below, but the present invention is not limited to these.

[0244]

[0245]

[0246] In the resist composition, the content of the boron-containing compound (C) is preferably 1.0 mass% or more, more preferably 2.0 mass% or more, and even more preferably 4.0 mass% or more, based on the total solid content of the resist composition. The upper limit is preferably 30.0 mass% or less, more preferably 25.0 mass% or less, even more preferably 20.0 mass% or less, and particularly preferably 10.0 mass% or less. The boron-containing compound (C) may be used alone or in combination. When two or more types are used, the total content thereof is preferably within the above-mentioned preferred content range.

[0247] [Onium Salt Compound (B)] The resist composition contains an onium salt compound (B) (hereinafter simply referred to as "onium salt compound (B)" or "photoacid generator (B)") that contains a cation having at least one fluorine atom and an anion and generates an acid upon irradiation with actinic rays or radiation. The photoacid generator (B) is a compound that generates an acid upon irradiation with actinic rays or radiation. The photoacid generator (B) may be in the form of a low molecular weight compound or a polymer. Examples of the polymeric form of the photoacid generator (B) include a form in which the photoacid generator is incorporated into a part of the above-mentioned resin (A) (acid-decomposable resin), and more specifically, a form in which the photoacid generator and the above-mentioned resin (A) (acid-decomposable resin) are linked by a covalent bond. Note that a photoacid generator in the form of a low molecular weight compound and a photoacid generator in the form of a polymer (for example, a form in which the photoacid generator is incorporated into a part of the above-mentioned resin (A) (acid-decomposable resin)) may be used in combination. When the photoacid generator (B) is in the form of a low molecular weight compound, the molecular weight of the photoacid generator is preferably 3,000 or less, more preferably 2,000 or less, and even more preferably 1,000 or less. There is no particular lower limit, but a molecular weight of 100 or more is preferred. When the photoacid generator (B) is in the form of being incorporated into a part of a polymer, it may be incorporated into a part of the resin (A) or into a resin different from the resin (A). In this specification, the photoacid generator (B) is preferably in the form of a low molecular weight compound. The photoacid generator (B) is an onium salt compound, and as described below, a sulfonium salt compound or an iodonium salt compound is preferred.

[0248] <Photoacid Generator PG1> An example of a preferred embodiment of the photoacid generator (B) is "M ＋ X － " which generates an organic acid upon exposure to light (hereinafter also referred to as "photoacid generator PG1"). ＋ X － In the compound represented by the formula ", M ＋ represents an organic cation, and X － represents an organic anion. ＋has at least one fluorine atom. Examples of the organic acid include sulfonic acids (aliphatic sulfonic acids, aromatic sulfonic acids, camphorsulfonic acids, etc.), carboxylic acids (aliphatic carboxylic acids, aromatic carboxylic acids, aralkyl carboxylic acids, etc.), carbonylsulfonylimido acids, bis(alkylsulfonyl)imido acids, and tris(alkylsulfonyl)methide acids. The pKa of the organic acid is preferably 2.0 or less, more preferably less than 0. The lower limit of the acid dissociation constant a1 is preferably -20.0 or more. The photoacid generator PG1 will be described below.

[0249] "M ＋ X － In the compound represented by the formula ", M ＋ represents an organic cation having at least one fluorine atom. The organic cation is not particularly limited as long as it has at least one fluorine atom. The valence of the organic cation may be monovalent or divalent or higher. Specific examples of the organic cation include cations having at least one fluorine atom in the cations (ZaI), (ZaII), (ZaIII), and (ZaIV) that may be contained in the above-mentioned boron-containing compound, and preferred embodiments are also the same as long as they have at least one fluorine atom.

[0250] Specifically, R in the above formula (ZaI) ２０１ ~R ２０３ an embodiment in which at least one of R in formula (ZaII) has a substituent having a fluorine atom; ２０４ and R ２０５ an embodiment in which at least one of R in formula (ZaIII) has a substituent having a fluorine atom; ３０１ ~R ３０４ an embodiment in which at least one of the following has a substituent having a fluorine atom; ３０１ and R ３０５ At least one of the above may have a substituent having a fluorine atom.

[0251] Examples of the substituent having a fluorine atom include a fluorine atom, an alkyl group having a fluorine atom as a substituent (for example, a linear alkyl group having 1 to 15 carbon atoms, and a branched alkyl group having 3 to 15 carbon atoms), a cycloalkyl group having a fluorine atom as a substituent (for example, a cycloalkyl group having 3 to 15 carbon atoms), and an alkoxy group having a fluorine atom as a substituent (for example, a linear alkoxy group having 1 to 15 carbon atoms, and a branched alkoxy group having 1 to 15 carbon atoms). Among these, a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group, and the like are preferred.

[0252] "M ＋ X － In the compound represented by the formula "X － represents an organic anion. The organic anion is not particularly limited, and examples thereof include monovalent or divalent or higher organic anions. As the organic anion, an anion having a significantly low ability to cause a nucleophilic reaction is preferred, and a non-nucleophilic anion is more preferred.

[0253] Examples of non-nucleophilic anions include sulfonate anions (aliphatic sulfonate anions, aromatic sulfonate anions, camphorsulfonate anions, etc.), carboxylate anions (aliphatic carboxylate anions, aromatic carboxylate anions, aralkyl carboxylate anions, etc.), sulfonylimide anions, bis(alkylsulfonyl)imide anions, and tris(alkylsulfonyl)methide anions.

[0254] The organic anion is preferably, for example, an organic anion represented by the following formula (DA).

[0255]

[0256] In formula (DA), A ３１－ represents an anionic group. ａ１ represents a hydrogen atom or a monovalent organic group. ａ１ represents a single bond or a divalent linking group.

[0257] A ３１－ represents an anionic group. ３１－The anionic group represented by the formula (B-1) is not particularly limited, but is preferably a group selected from the group consisting of groups represented by the formulas (B-1) to (B-14).

[0258]

[0259] *-O － Formula (B-14)

[0260] In formulas (B-1) to (B-14), * represents a bonding position. Ｘ１ Each independently represents a monovalent organic group. Ｘ２ Each of the two R in formula (B-7) independently represents a hydrogen atom or a substituent other than a fluorine atom or a perfluoroalkyl group. Ｘ２ may be the same or different. ＸＦ１ represents a hydrogen atom, a fluorine atom, or a perfluoroalkyl group, provided that two R ＸＦ１ At least one of the two R in formula (B-8) represents a fluorine atom or a perfluoroalkyl group. ＸＦ１ may be the same or different. Ｘ３ represents a hydrogen atom, a halogen atom, or a monovalent organic group. n1 represents an integer of 0 to 4. When n1 represents an integer of 2 to 4, a plurality of R Ｘ３ may be the same or different. ＸＦ２ represents a fluorine atom or a perfluoroalkyl group. The bond to the bonding position represented by * in formula (B-14) is preferably a phenylene group which may have a substituent. Examples of the substituent which the phenylene group may have include a halogen atom.

[0261] In formulas (B-1) to (B-5) and (B-12), R Ｘ１ R each independently represents a monovalent organic group. Ｘ１As the R, an alkyl group (which may be linear or branched, and preferably has 1 to 15 carbon atoms), a cycloalkyl group (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms), or an aryl group (which may be monocyclic or polycyclic, and preferably has 6 to 20 carbon atoms) is preferred. Ｘ１ The above group represented by the formula (B-5) may have a substituent. Ｘ１ The atom directly bonded to N- in -CO- and -SO ２ It is also preferred that neither of the sulfur atoms in - is present.

[0262] R Ｘ１ The cycloalkyl group in R may be monocyclic or polycyclic. Ｘ１ Examples of the cycloalkyl group in the formula include a norbornyl group and an adamantyl group.

[0263] R Ｘ１ The substituent that the cycloalkyl group in R may have is not particularly limited, but is preferably an alkyl group (which may be linear or branched, and preferably has 1 to 5 carbon atoms). Ｘ１ One or more of the carbon atoms which are ring members of the cycloalkyl group in the formula (I) may be replaced by a carbonyl carbon atom.

[0264] R Ｘ１ The alkyl group in R preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms. Ｘ１ The substituent that the alkyl group in R may have is not particularly limited, but is preferably, for example, a cycloalkyl group, a fluorine atom, or a cyano group. Examples of the cycloalkyl group as the substituent include R Ｘ１ The same cycloalkyl groups as those described above when R is a cycloalkyl group are exemplified. Ｘ１ When the alkyl group in R has a fluorine atom as the substituent, the alkyl group may be a perfluoroalkyl group. Ｘ１ The alkyl group in ２ - may be substituted with a carbonyl group.

[0265] R Ｘ１The aryl group in R is preferably a benzene ring group. Ｘ１ The substituent that the aryl group in R may have is not particularly limited, but is preferably an alkyl group, a fluorine atom, or a cyano group. Ｘ１ The alkyl groups described above when is an alkyl group are also included.

[0266] In formulas (B-7) and (B-11), R Ｘ２ each independently represents a hydrogen atom or a substituent other than a fluorine atom or a perfluoroalkyl group (for example, an alkyl group not containing a fluorine atom and a cycloalkyl group not containing a fluorine atom). Ｘ２ may be the same or different.

[0267] In formula (B-8), R ＸＦ１ represents a hydrogen atom, a fluorine atom, or a perfluoroalkyl group. ＸＦ１ At least one of the two R in formula (B-8) represents a fluorine atom or a perfluoroalkyl group. ＸＦ１ may be the same or different. ＸＦ１ The perfluoroalkyl group represented by the formula (I) preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms.

[0268] In formula (B-9), R Ｘ３ represents a hydrogen atom, a halogen atom, or a monovalent organic group. Ｘ３ Examples of the halogen atom as R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and among these, a fluorine atom is preferred. Ｘ３ The monovalent organic group as R Ｘ１ n1 represents an integer of 0 to 4. n1 is preferably an integer of 0 to 2, and more preferably 0 or 1. When n1 represents an integer of 2 to 4, a plurality of R Ｘ３ may be the same or different.

[0269] In formula (B-10), R ＸＦ２ represents a fluorine atom or a perfluoroalkyl group.ＸＦ２ The perfluoroalkyl group represented by the formula (I) preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms.

[0270] In formula (DA), R ａ１ The monovalent organic group R is not particularly limited, but generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. ａ１ is preferably an alkyl group, a cycloalkyl group, or an aryl group.

[0271] The alkyl group may be linear or branched, and is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and even more preferably an alkyl group having 1 to 10 carbon atoms. The cycloalkyl group may be monocyclic or polycyclic, and is preferably a cycloalkyl group having 3 to 20 carbon atoms, more preferably a cycloalkyl group having 3 to 15 carbon atoms, and even more preferably a cycloalkyl group having 3 to 10 carbon atoms. The aryl group may be monocyclic or polycyclic, and is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms, and even more preferably an aryl group having 6 to 10 carbon atoms.

[0272] The cycloalkyl group may contain a heteroatom as a ring member atom. Examples of the heteroatom include, but are not limited to, a nitrogen atom and an oxygen atom. The cycloalkyl group may also contain a carbonyl bond (>C=O) as a ring member atom. The alkyl group, cycloalkyl group, and aryl group may further have a substituent.

[0273] L ａ１ The divalent linking group as is not particularly limited, and may be an alkylene group, a cycloalkylene group, an aromatic group, —O—, —CO—, —SO—, —SO ２-, and groups formed by combining two or more of these. The alkylene group may be linear or branched, and preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms. The cycloalkylene group may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms. The aromatic group is a divalent aromatic group, and preferably has 6 to 20 carbon atoms, and more preferably has 6 to 15 carbon atoms. The aromatic ring constituting the aromatic group is not particularly limited, but examples include aromatic rings having 6 to 20 carbon atoms, and specific examples include a benzene ring, a naphthalene ring, an anthracene ring, and a thiophene ring. The aromatic ring constituting the aromatic group is preferably a benzene ring or a naphthalene ring, and more preferably a benzene ring. The alkylene group, cycloalkylene group, and aromatic group may further have a substituent, and the substituent is preferably a halogen atom. In addition, A ３１－ and R ａ１ may be bonded to each other to form a ring.

[0274] As the photoacid generator PG1, it is also preferable to use, for example, the photoacid generators disclosed in paragraphs

[0135] to

[0171] of WO 2018 / 193954, paragraphs

[0077] to

[0116] of WO 2020 / 066824, and paragraphs

[0018] to

[0075] and

[0334] to

[0335] of WO 2017 / 154345.

[0275] The molecular weight of the photoacid generator PG1 is preferably 3,000 or less, more preferably 2,000 or less, and even more preferably 1,000 or less.

[0276] <Photoacid generator PG2> Another suitable example of the photoacid generator (B) is the following compound (I) (hereinafter also referred to as "photoacid generator PG2"). Photoacid generator PG2 is a compound that has two or more of the above-mentioned salt structure moieties and generates a polyvalent organic acid upon exposure to light. Photoacid generator PG2 will be described below.

[0277] (Compound (I)) Compound (I) is a compound having one or more structural moieties X and one or more structural moieties Y, which generates an acid containing the first acidic moiety derived from the structural moiety X and the second acidic moiety derived from the structural moiety Y when irradiated with actinic rays or radiation. Structural moiety X: Anionic moiety A １ － and the cationic moiety M １ ＋ and HA is produced by irradiation with actinic rays or radiation. １ Structural moiety Y: anionic moiety A, which forms a first acidic moiety represented by the formula: ２ － and the cationic moiety M ２ ＋ and HA is produced by irradiation with actinic rays or radiation. ２ A structural moiety forming a second acidic moiety represented by the following formula (I):

[0278] Condition I: In the compound (I), the cationic moiety M in the structural moiety X １ ＋ and the cationic moiety M in the structural moiety Y ２ ＋ H ＋ The compound PI in which the cation moiety M in the structural moiety X is replaced by １ ＋ H ＋ HA is replaced by １ and the cationic moiety M in the structural moiety Y. ２ ＋ H ＋ HA is replaced by ２ and the acid dissociation constant a2 is greater than the acid dissociation constant a1.

[0279] One embodiment of compound (I) is an embodiment having two structural moieties X and one structural moiety Y.

[0280] For example, when compound (I) is a compound having two structural moieties X and one structural moiety Y (i.e., an acid-generating compound having two of the first acidic moieties derived from the structural moiety X and one of the second acidic moieties derived from the structural moiety Y), compound PI is a compound having "two HAs" １ and one HA ２ When the acid dissociation constant of compound PI is calculated, compound PI corresponds to "a compound having one A １ － and one HA １ and one HA ２ and the acid dissociation constant when "a compound having one A １ － and one HA １ and one HA ２ "Compound having two A １ － and one HA ２ The acid dissociation constant when the compound is a compound having two A's corresponds to the acid dissociation constant a1 described above. １ － and one HA ２ "Compound having two A １ － and A ２ － In other words, in the case of compound PI, the acid dissociation constant when the compound becomes a compound having the cation moiety M in the structural moiety X corresponds to the acid dissociation constant a2. １ ＋ H ＋ HA is replaced by １ When the compound PI has a plurality of acid dissociation constants derived from the acidic moiety represented by the formula (I), the value of the acid dissociation constant a2 is larger than the largest value of the plurality of acid dissociation constants a1. １ － and one HA １ and one HA ２ The acid dissociation constant when the compound is aa is defined as "a compound having one A １ － and one HA １ and one HA ２ "Compound having two A １ － and one HA２ When the acid dissociation constant when the compound becomes "a compound having the formula (I)" is ab, the relationship between aa and ab satisfies aa<ab.

[0281] The acid dissociation constants a1 and a2 can be determined by the above-mentioned method for measuring an acid dissociation constant. The compound PI corresponds to the acid generated when compound (I) is irradiated with actinic rays or radiation.

[0282] In the compound PI, the difference (absolute value) between the acid dissociation constant a1 (the maximum value when there are multiple acid dissociation constants a1) and the acid dissociation constant a2 is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 1.0 or more. The upper limit of the difference (absolute value) between the acid dissociation constant a1 (the maximum value when there are multiple acid dissociation constants a1) and the acid dissociation constant a2 is not particularly limited, but is, for example, 16 or less.

[0283] In the compound PI, the acid dissociation constant a2 is preferably 20 or less, and more preferably 15 or less. The lower limit of the acid dissociation constant a2 is preferably −4.0 or more, more preferably −1.0 or more, even more preferably 0 or more, and most preferably 0.5 or more.

[0284] In the compound PI, the acid dissociation constant a1 is preferably 2.0 or less, and more preferably less than 0. The lower limit of the acid dissociation constant a1 is preferably −20.0 or more.

[0285] When compound (I) has two or more structural moieties X, the structural moieties X may be the same or different from each other. １ － , and two or more of the above M １ ＋ may be the same or different. １ － and the above A ２ － , and the above M １ ＋ and the above M ２ ＋ may be the same or different, but １ － and the above A２ － are preferably different from each other.

[0286] Anion site A １ － and anionic moiety A ２ － is a structural moiety containing a negatively charged atom or atomic group, and examples thereof include structural moieties selected from the group consisting of formulae (AA-1) to (AA-3) and formulae (BB-1) to (BB-6) shown below. １ － As the anionic moiety A, those capable of forming an acidic moiety with a small acid dissociation constant are preferred, and among these, any of formulas (AA-1) to (AA-3) is more preferred, and any of formulas (AA-1) and (AA-3) is even more preferred. ２ － As the anion moiety A １ － Preferably, it is one that can form an acidic site with a larger acid dissociation constant than the above, more preferably any of formulas (BB-1) to (BB-6), and even more preferably any of formulas (BB-1) and (BB-4). In the following formulas (AA-1) to (AA-3) and formulas (BB-1) to (BB-6), * represents a bonding position. In formula (AA-2), R Ａ represents a monovalent organic group. Ａ The monovalent organic group represented by the formula (I) is not particularly limited, but examples thereof include a cyano group, a trifluoromethyl group, and a methanesulfonyl group.

[0287]

[0288]

[0289] Cationic moiety M １ ＋ and cationic moiety M ２ ＋ is a structural moiety containing a positively charged atom or atomic group, and examples thereof include monovalent organic cations. Specific examples of the organic cations include the above-mentioned M ＋ Specific examples are given in the above, and preferred embodiments are also the same. The organic cation contains a fluorine atom.

[0290] The molecular weight of the photoacid generator PG2 is preferably 100 to 10,000, more preferably 100 to 2,500, and even more preferably 100 to 1,500.

[0291] Examples of the photoacid generator PG2 include the compounds exemplified in paragraphs

[0023] to

[0078] of WO 2020 / 158313.

[0292] The content of the photoacid generator (B) in the resist composition is not particularly limited, but from the viewpoint of improving the resolution and roughness performance of the formed pattern, it is preferably 0.5% by mass or more, more preferably 5.0% by mass or more, even more preferably 10.0% by mass or more, and particularly preferably 20.0% by mass or more, based on the total solid content of the resist composition. The content is preferably 50.0% by mass or less, more preferably 45.0% by mass or less, and even more preferably 40.0% by mass or less, based on the total solid content of the resist composition. The photoacid generator may be used alone, or two or more types may be used. When two or more types are used, it is preferable that the total content is within the above-mentioned suitable content range.

[0293] The resist composition may further contain another photoacid generator that generates an acid upon irradiation with actinic rays or radiation and is different from the photoacid generator (B). The content of the other photoacid generator in the resist composition is not particularly limited, but is preferably 0.5% by mass or more, more preferably 5.0% by mass or more, even more preferably 10.0% by mass or more, and particularly preferably 20.0% by mass or more, relative to the total solids content of the resist composition. The content is preferably 50.0% by mass or less, more preferably 45.0% by mass or less, and even more preferably 40.0% by mass or less, relative to the total solids content of the resist composition.

[0294] [Acid Diffusion Controller] The resist composition preferably contains an acid diffusion controller. The acid diffusion controller traps the acid generated from the photoacid generator or the like during exposure, and acts as a quencher that suppresses the reaction of the acid-decomposable resin in unexposed areas due to excess generated acid. The type of acid diffusion controller is not particularly limited, and examples include basic compounds (DA), compounds (DB) whose basicity is reduced or eliminated by irradiation with actinic rays or radiation, low-molecular-weight compounds (DC) having a group that is cleaved by the action of an acid, and onium salt compounds (DD) that generate an acid that is weaker than the photoacid generator. Specific examples of the basic compound (DA) include those described in paragraphs

[0132] to

[0136] of WO 2020 / 066824. Specific examples of the basic compound (DB) whose basicity is reduced or eliminated by irradiation with actinic rays or radiation include those described in paragraphs

[0137] to

[0155] of WO 2020 / 066824. Specific examples of the low molecular weight compound (DC) having a group that leaves under the action of an acid include those described in paragraphs

[0156] to

[0163] of WO 2020 / 066824. Specific examples of the onium salt compound (DD) that generates an acid that is relatively weakly acidic to the photoacid generator include those described in paragraph

[0164] of WO 2020 / 066824. Specific examples of the onium salt compound (DD) that generates an acid that is weaker than the photoacid generator include those described in paragraphs

[0305] to

[0314] of WO 2020 / 158337.

[0295] In addition to the above, for example, known compounds disclosed in paragraphs

[0627] to

[0664] of U.S. Patent Application Publication No. 2016 / 0070167A1, paragraphs

[0095] to

[0187] of U.S. Patent Application Publication No. 2015 / 0004544A1, paragraphs

[0403] to

[0423] of U.S. Patent Application Publication No. 2016 / 0237190A1, and paragraphs

[0259] to

[0328] of U.S. Patent Application Publication No. 2016 / 0274458A1 can be suitably used as the acid diffusion controller.

[0296] When the acid diffusion controller is an onium salt compound (DD) that generates an acid that is weaker than the photoacid generator, the acid dissociation constant of the generated acid is preferably 20 or less, more preferably 15 or less. The lower limit of the acid dissociation constant is preferably −4.0 or more, more preferably −1.0 or more, even more preferably 0 or more, and most preferably 0.5 or more. The onium salt compound is preferably a sulfonium salt compound or an iodonium salt compound.

[0297] When the resist composition contains an acid diffusion controller, the content of the acid diffusion controller (or the total content if multiple types are present) is preferably 0.1 to 20.0 mass%, more preferably 0.1 to 15.0 mass%, and even more preferably 1.0 to 15.0 mass%, relative to the total solids content of the resist composition. In the resist composition, one type of acid diffusion controller may be used alone, or two or more types may be used in combination. When two or more types are used, the total content thereof preferably falls within the above-mentioned preferred content range.

[0298] [Surfactant] The resist composition may contain a surfactant. When the resist composition contains a surfactant, it is possible to form a pattern with better adhesion and fewer development defects. The surfactant is preferably a fluorine-based and / or silicon-based surfactant. Examples of the fluorine-based and / or silicon-based surfactant include the surfactants disclosed in paragraphs

[0218] and

[0219] of WO 2018 / 193954.

[0299] These surfactants may be used alone or in combination of two or more.

[0300] When the resist composition contains a surfactant, the content of the surfactant is preferably from 0.0001 to 2.0 mass%, more preferably from 0.0005 to 1.0 mass%, and even more preferably from 0.1 to 1.0 mass%, relative to the total solids content of the resist composition. When two or more surfactants are used, the total content thereof preferably falls within the above-mentioned preferred content range.

[0301] [Hydrophobic Resin] The resist composition may further contain a hydrophobic resin different from the resin (A). The hydrophobic resin is preferably designed so as to be unevenly distributed on the surface of the resist film, but unlike surfactants, it does not necessarily have to have a hydrophilic group in its molecule, and it does not necessarily have to contribute to uniform mixing of polar and non-polar substances. The effects of adding a hydrophobic resin include controlling the static and dynamic contact angles of the resist film surface with water, and suppressing outgassing.

[0302] The hydrophobic resin contains fluorine atoms, silicon atoms, and CH atoms contained in the side chain portion of the resin in order to be unevenly distributed on the surface layer of the film. ３ It is preferable to have one or more of the partial structures, and more preferably two or more. The hydrophobic resin preferably has a hydrocarbon group having 5 or more carbon atoms. These groups may be present in the main chain of the resin or may be substituted on a side chain. Examples of hydrophobic resins include the compounds described in paragraphs

[0275] to

[0279] of WO 2020 / 004306.

[0303] When the resist composition contains a hydrophobic resin, the content of the hydrophobic resin is preferably 0.01 to 20.0 mass%, and more preferably 0.1 to 15.0 mass%, relative to the total solids content of the resist composition. In the resist composition, one hydrophobic resin may be used alone, or two or more hydrophobic resins may be used in combination. When two or more hydrophobic resins are used, the total content thereof preferably falls within the above-mentioned preferred content range.

[0304] [Solvent] The resist composition preferably contains a solvent. The solvent preferably contains (M1) propylene glycol monoalkyl ether carboxylate and (M2) at least one selected from the group consisting of propylene glycol monoalkyl ether, lactate ester, acetate ester, alkoxypropionate ester, chain ketone, cyclic ketone, lactone (e.g., γ-butyrolactone), and alkylene carbonate. The solvent may further contain components other than components (M1) and (M2).

[0305] Combining the above-mentioned solvent with the above-mentioned resin is preferable in terms of improving the coatability of the resist composition and reducing the number of development defects in the pattern. The above-mentioned solvent has a good balance of the solubility, boiling point, and viscosity of the above-mentioned resin, and can therefore suppress unevenness in the film thickness of the resist film and the occurrence of precipitates during spin coating. Details of component (M1) and component (M2) are described in paragraphs

[0218] to

[0226] of WO 2020 / 004306, the contents of which are incorporated herein by reference.

[0306] When the solvent further contains components other than the components (M1) and (M2), the content of the components other than the components (M1) and (M2) is preferably 5 to 30 mass % based on the total amount of the solvent.

[0307] The content of the solvent in the resist composition is preferably determined so that the solids concentration is 0.5 to 30 mass %, and more preferably 1 to 20 mass %, which further improves the coatability of the resist composition.

[0308] [Other Additives] The resist composition may further contain a dissolution inhibiting compound, a dye, a plasticizer, a photosensitizer, a light absorber, and / or a compound that promotes solubility in a developer (for example, a phenol compound having a molecular weight of 1,000 or less, or an alicyclic or aliphatic compound containing a carboxyl group).

[0309] The "dissolution inhibiting compound" is a compound having a molecular weight of 3,000 or less that is decomposed by the action of an acid and has a reduced solubility in an organic solvent-based developer.

[0310] The resist composition is suitable for use as a photosensitive composition for EUV exposure. EUV has a wavelength of 13.5 nm, which is shorter than ArF (wavelength 193 nm) light and the like, and therefore the number of incident photons is smaller when exposed at the same sensitivity. As a result, the effect of "photon shot noise," in which the number of photons varies stochastically, is significant, leading to worsening of line edge roughness (LER) and bridge defects. One way to reduce photon shot noise is to increase the exposure dose to increase the number of incident photons, but this comes at a trade-off with the demand for higher sensitivity.

[0311] When the value A calculated by the following formula (1) is high, the resist film formed from the resist composition has a high absorption efficiency for EUV and electron beams, which is effective in reducing photon shot noise. The value A represents the mass ratio of the resist film to the absorption efficiency for EUV and electron beams. Formula (1): A = ([H] x 0.04 + [C] x 1.0 + [N] x 2.1 + [O] x 3.6 + [F] x 5.6 + [S] x 1.5 + [I] x 39.5) / ([H] x 1 + [C] x 12 + [N] x 14 + [O] x 16 + [F] x 19 + [S] x 32 + [I] x 127). The value A is preferably 0.120 or greater. There is no particular upper limit to the A value, but if the A value is too large, the EUV and electron beam transmittance of the resist film decreases, the optical image profile in the resist film deteriorates, and as a result, it becomes difficult to obtain a good pattern shape. Therefore, the A value is preferably 0.240 or less, and more preferably 0.220 or less.

[0312] In formula (1), [H] represents the molar ratio of hydrogen atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition, [C] represents the molar ratio of carbon atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition, [N] represents the molar ratio of nitrogen atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition, and [O] represents the molar ratio of nitrogen atoms derived from all solids to all atoms in all solids in the actinic ray-sensitive or radiation-sensitive resin composition. [F] represents the molar ratio of oxygen atoms derived from all solids to all atoms in all solids, [F] represents the molar ratio of fluorine atoms derived from all solids to all atoms in all solids in the actinic ray- or radiation-sensitive resin composition, [S] represents the molar ratio of sulfur atoms derived from all solids to all atoms in all solids in the actinic ray- or radiation-sensitive resin composition, and [I] represents the molar ratio of iodine atoms derived from all solids to all atoms in all solids in the actinic ray- or radiation-sensitive resin composition. For example, when a resist composition contains an acid-decomposable resin, a photoacid generator, an acid diffusion controller, and a solvent, the acid-decomposable resin, the photoacid generator, and the acid diffusion controller correspond to the solids. In other words, the total atoms in all solids correspond to the sum of all atoms derived from the resin, all atoms derived from the photoacid generator, and all atoms derived from the acid diffusion controller. For example, [H] represents the molar ratio of hydrogen atoms derived from all solids to all atoms in all solids. Explaining based on the above example, [H] represents the molar ratio of the sum of hydrogen atoms derived from the acid-decomposable resin, the photoacid generator, and the acid diffusion controller to the sum of all atoms derived from the acid-decomposable resin, the photoacid generator, and the acid diffusion controller.

[0313] The A value can be calculated by calculating the atomic ratio of the components contained in the resist composition when the structures and contents of the components of the total solid content of the resist composition are known. Even when the components are unknown, the atomic ratio of the components can be calculated by analytical techniques such as elemental analysis of a resist film obtained by evaporating the solvent component of the resist composition.

[0314] [Method of forming a resist film and a pattern] The procedure of the method of forming a pattern using the resist composition is not particularly limited, but it is preferable that the method include the following steps: Step 1: forming a resist film on a substrate using the resist composition Step 2: exposing the resist film to light Step 3: developing the exposed resist film using a developer The procedure of each of the above steps will be described in detail below.

[0315] <Step 1: Resist Film Forming Step> Step 1 is a step of forming a resist film on a substrate using a resist composition. The definition of the resist composition is as described above.

[0316] A method for forming a resist film on a substrate using a resist composition includes, for example, applying the resist composition to the substrate. It is preferable to filter the resist composition before application, if necessary. The pore size of the filter is preferably 0.1 μm or less, more preferably 0.05 μm or less, and even more preferably 0.03 μm or less. The filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon.

[0317] The resist composition can be applied onto a substrate (e.g., silicon, silicon dioxide coated) such as those used in the manufacture of integrated circuit elements by an appropriate application method such as a spinner or coater. Spin application using a spinner is preferred. The rotation speed when spin application using a spinner is preferably 1000 to 3000 rpm. After application of the resist composition, the substrate may be dried to form a resist film. If necessary, various undercoating films (inorganic film, organic film, anti-reflective film) may be formed below the resist film.

[0318] An example of a drying method is a method of drying by heating. Heating can be performed by means provided in a normal exposure machine and / or developing machine, and may also be performed using a hot plate or the like. The heating temperature is preferably 80 to 150°C, more preferably 80 to 140°C, and even more preferably 80 to 130°C. The heating time is preferably 30 to 1,000 seconds, more preferably 60 to 800 seconds, and even more preferably 60 to 600 seconds.

[0319] The thickness of the resist film is not particularly limited, but is preferably 10 to 120 nm from the viewpoint of forming a finer pattern with higher precision. In particular, when EUV exposure is used, the thickness of the resist film is more preferably 10 to 65 nm, and even more preferably 15 to 50 nm. When ArF immersion exposure is used, the thickness of the resist film is more preferably 10 to 120 nm, and even more preferably 15 to 90 nm.

[0320] A top coat may be formed on the resist film using a top coat composition. It is preferable that the top coat composition does not mix with the resist film and can be uniformly applied to the resist film. The top coat is not particularly limited, and a conventionally known top coat can be formed by a conventionally known method. For example, a top coat can be formed based on the description in paragraphs

[0072] to

[0082] of JP 2014-059543 A. For example, a top coat containing a basic compound such as that described in JP 2013-61648 A is preferably formed on the resist film. Specific examples of basic compounds that may be contained in the top coat include basic compounds that may be contained in the resist composition. It is also preferable that the top coat contain a compound containing at least one group or bond selected from the group consisting of an ether bond, a thioether bond, a hydroxyl group, a thiol group, a carbonyl bond, and an ester bond.

[0321] <Step 2: Exposure Step> Step 2 is a step of exposing the resist film. Examples of exposure methods include irradiating the formed resist film with actinic rays or radiation through a predetermined mask. Examples of actinic rays or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-rays, and electron beams, and preferably have a wavelength of 250 nm or less, more preferably 220 nm or less, and far ultraviolet light having a wavelength of 1 to 200 nm, specifically, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ２ Excimer laser (157 nm), EUV (13.5 nm), X-ray, and electron beam are particularly preferred.

[0322] After exposure, it is preferable to bake (heat) the film before developing. Baking promotes the reaction of the exposed areas, resulting in better sensitivity and pattern shape. The heating temperature is preferably 80 to 150°C, more preferably 80 to 140°C, and even more preferably 80 to 130°C. The heating time is preferably 10 to 1,000 seconds, more preferably 10 to 180 seconds, and even more preferably 30 to 120 seconds. Heating can be performed using means provided in a typical exposure machine and / or development machine, and may also be performed using a hot plate or the like. This process is also called post-exposure baking.

[0323] <Step 3: Development Step> Step 3 is a step of developing the exposed resist film with a developer to form a pattern. The developer may be either an organic solvent-based developer (a developer containing an organic solvent) or an alkaline developer, but an organic solvent-based developer is preferred.

[0324] Examples of development methods include a method in which a substrate is immersed in a tank filled with a developer for a certain period of time (dip method), a method in which a developer is piled up on the surface of a substrate by surface tension and left to stand for a certain period of time for development (puddle method), a method in which a developer is sprayed onto the surface of the substrate (spray method), and a method in which a developer is continuously dispensed onto a substrate rotating at a constant speed while a developer dispense nozzle is scanned at a constant speed (dynamic dispense method). Furthermore, after the development step, a step of stopping development while replacing the solvent with another solvent may be carried out. The development time is not particularly limited as long as it is long enough to sufficiently dissolve the resin in the unexposed areas, and is preferably 10 to 300 seconds, more preferably 20 to 120 seconds. The temperature of the developer is preferably 0 to 50°C, more preferably 15 to 35°C.

[0325] The alkaline developer is preferably an aqueous alkaline solution containing an alkali. The type of alkaline aqueous solution is not particularly limited, but examples include aqueous alkaline solutions containing a quaternary ammonium salt, such as tetramethylammonium hydroxide, an inorganic alkali, a primary amine, a secondary amine, a tertiary amine, an alcohol amine, or a cyclic amine. Of these, the alkaline developer is preferably an aqueous solution of a quaternary ammonium salt, such as tetramethylammonium hydroxide (TMAH). Appropriate amounts of alcohols, surfactants, and the like may be added to the alkaline developer. The alkaline concentration of the alkaline developer is usually preferably 0.1 to 20% by mass. The pH of the alkaline developer is usually preferably 10.0 to 15.0.

[0326] The organic developer is preferably a developer containing at least one organic solvent selected from the group consisting of ketone-based solvents, ester-based solvents, alcohol-based solvents, amide-based solvents, ether-based solvents, and hydrocarbon-based solvents.

[0327] The above-mentioned solvents may be mixed in plural, or may be mixed with a solvent other than the above or water. The water content of the developer as a whole is preferably less than 50% by mass, more preferably less than 20% by mass, even more preferably less than 10% by mass, and particularly preferably substantially free of water. The content of the organic solvent in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, and particularly preferably 95% by mass or more and 100% by mass or less, based on the total amount of the developer.

[0328] Preferred embodiments of the organic developer include the following embodiments (OD1) and (OD2). (OD1) An embodiment in which the organic developer is n-butyl acetate. (OD2) An embodiment in which the organic developer is a mixed solvent of n-butyl acetate and a hydrocarbon having 11 or more carbon atoms. The mixed solvent of (OD2) above is also referred to as mixed solvent (OD2). The hydrocarbon having 11 or more carbon atoms in mixed solvent (OD2) is preferably an alkane, more preferably an alkane having 11 to 15 carbon atoms, even more preferably an alkane having 11 to 13 carbon atoms, particularly preferably undecane or dodecane, and most preferably undecane. Note that when structural isomers exist, such as undecane and dodecane, the hydrocarbon having 11 or more carbon atoms may contain the structural isomer. The hydrocarbon having 11 or more carbon atoms contained in mixed solvent (OD2) may be one type or two or more types. The content of hydrocarbons having 11 or more carbon atoms in the mixed solvent (OD2) (the total amount when multiple hydrocarbons having 11 or more carbon atoms are contained) is preferably 1% by mass or more and 35% by mass or less, more preferably 5% by mass or more and 30% by mass or less, and even more preferably 10% by mass or more and 25% by mass or less, based on 100% by mass of the entire mixed solvent (OD2).

[0329] The content of n-butyl acetate in the mixed solvent (OD2) is preferably 65% ​​by mass or more and 99% by mass or less, more preferably 70% by mass or more and 95% by mass or less, and even more preferably 75% by mass or more and 90% by mass or less, with the entire mixed solvent (OD2) being 100% by mass.

[0330] A particularly preferred embodiment of the mixed solvent (OD2) is one containing n-butyl acetate and undecane, with the mass ratio of "n-butyl acetate / undecane" being "90 / 10".

[0331] The developer may contain other components in addition to the components described above. Examples of other components include surfactants, antioxidants, basic compounds, etc. The content of other components in the developer is preferably 0% by mass or more and 5% by mass or less, more preferably 0% by mass or more and 1% by mass or less, even more preferably 0% by mass or more and 0.5% by mass or less, based on 100% by mass of the entire developer, and particularly preferably 0% by mass (i.e., no other components are contained).

[0332] <Other Steps> The pattern formation method preferably includes, after step 3, a step of cleaning with a rinse liquid.

[0333] The rinse liquid used in the rinse step after the development step using an organic solvent-based developer is preferably an organic solvent-based rinse liquid. The organic solvent contained in the rinse liquid is preferably at least one organic solvent selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents.

[0334] The rinse liquid used in the rinse step after the development step using an alkaline developer can be, for example, pure water. A suitable amount of surfactant may be added to the pure water. A suitable amount of surfactant may be added to the rinse liquid.

[0335] The method for the rinsing step is not particularly limited, and examples include a method in which a rinsing solution is continuously discharged onto a substrate rotating at a constant speed (spin coating method), a method in which a substrate is immersed in a tank filled with the rinsing solution for a certain period of time (dipping method), and a method in which the rinsing solution is sprayed onto the substrate surface (spray method). The pattern formation method may also include a heating step (post-bake) after the rinsing step. This step removes the developer and rinsing solution remaining between and within the pattern by baking. This step also has the effect of annealing the resist pattern and improving the surface roughness of the pattern. The heating step after the rinsing step is typically performed at 40 to 250°C (preferably 90 to 200°C) for typically 10 seconds to 3 minutes (preferably 30 to 120 seconds).

[0336] Alternatively, the substrate may be etched using the formed pattern as a mask. That is, the substrate (or the underlayer film and the substrate) may be processed using the pattern formed in step 3 as a mask to form a pattern on the substrate. The method for processing the substrate (or the underlayer film and the substrate) is not particularly limited, but a method of forming a pattern on the substrate by dry etching the substrate (or the underlayer film and the substrate) using the pattern formed in step 3 as a mask is preferred. The dry etching is preferably oxygen plasma etching.

[0337] The resist composition and various materials used in the pattern formation method of the present specification (e.g., solvent, developer, rinse, anti-reflective coating-forming composition, top coat-forming composition, etc.) preferably do not contain impurities such as metals. The content of impurities contained in these materials is preferably 1 mass ppm or less, more preferably 10 mass ppb or less, even more preferably 100 mass ppt or less, particularly preferably 10 mass ppt or less, and most preferably 1 mass ppt or less. There is no particular lower limit, and 0 mass ppt or more is preferred. Here, examples of metal impurities include Na, K, Ca, Fe, Cu, Mg, Al, Li, Cr, Ni, Sn, Ag, As, Au, Ba, Cd, Co, Pb, Ti, V, W, and Zn.

[0338] Examples of methods for removing impurities such as metals from various materials include filtration using a filter. Details of filtration using a filter are described in paragraph

[0321] of WO 2020 / 004306.

[0339] Methods for reducing impurities such as metals contained in various materials include, for example, selecting raw materials with a low metal content as raw materials for the various materials, filtering the raw materials for the various materials, and performing distillation under conditions that minimize contamination as much as possible, for example by lining the inside of the apparatus with Teflon (registered trademark).

[0340] In addition to filter filtration, impurities may be removed using an adsorbent, or a combination of filter filtration and an adsorbent may be used. Known adsorbents can be used as the adsorbent, including inorganic adsorbents such as silica gel and zeolite, and organic adsorbents such as activated carbon. In order to reduce impurities such as metals contained in the various materials, it is necessary to prevent the incorporation of metal impurities during the manufacturing process. Whether metal impurities have been sufficiently removed from the manufacturing equipment can be confirmed by measuring the content of metal components contained in the cleaning solution used to clean the manufacturing equipment. The content of metal components contained in the used cleaning solution is preferably 100 parts per trillion (ppt) by mass or less, more preferably 10 ppt by mass or less, and even more preferably 1 ppt by mass or less. There is no particular lower limit, and 0 ppt by mass or more is preferred.

[0341] A conductive compound may be added to an organic processing liquid such as a rinse solution to prevent breakdown of the chemical solution piping and various parts (filters, O-rings, tubes, etc.) due to static charging and subsequent electrostatic discharge. The conductive compound is not particularly limited, but examples include methanol. The amount added is not particularly limited, but in order to maintain favorable development or rinsing characteristics, it is preferably 10% by mass or less, more preferably 5% by mass or less. There is no particular lower limit, but 0.01% by mass or more is preferred. For the chemical solution piping, for example, stainless steel (SUS), or various piping coated with antistatically treated polyethylene, polypropylene, or fluororesin (such as polytetrafluoroethylene or perfluoroalkoxy resin), can be used. Similarly, for the filters and O-rings, antistatically treated polyethylene, polypropylene, or fluororesin (such as polytetrafluoroethylene or perfluoroalkoxy resin), can be used.

[0342] [Method for Manufacturing an Electronic Device] The present specification also relates to a method for manufacturing an electronic device, including the above-mentioned pattern formation method, and an electronic device manufactured by this manufacturing method. Preferred embodiments of the electronic device of the present specification include those installed in electrical and electronic devices (such as home appliances, office automation (OA), media-related devices, optical devices, and communication devices).

[0343] The present invention will be described in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below.

[0344] [Various Components of Actinic Ray-Sensitive or Radiation-Sensitive Resin Composition] [Resin (A)] The resins shown in Table 2 below (Resins P-1 to P-21 and HP-1 to HP-2) are shown below. The resins used were synthesized according to the synthesis method for Resin A-1 (Synthesis Example 1) described below and known methods. Table 1 shows the compositions of Resins P-1 to P-21 and HP-1 to HP-2 (type of repeating unit, composition ratio of repeating units (mass %), weight average molecular weight (Mw), and dispersity (Mw / Mn)). The weight average molecular weight (Mw), number average molecular weight (Mn), and polydispersity (Mw / Mn) of resins P-1 to P-21 and HP-1 to HP-2 were measured as polystyrene equivalent values ​​using a Gel Permeation Chromatography (GPC) apparatus (Tosoh Corporation, HLC-8120GPC) (solvent: tetrahydrofuran, flow rate (sample injection amount): 10 μL, column: Tosoh Corporation TSK gel Multipore HXL-M, column temperature: 40 ° C., flow rate: 1.0 mL / min, detector: differential refractive index detector). The composition ratio (mass %) of the resins was measured as １３ The molar composition ratio was determined by C-NMR (Nuclear Magnetic Resonance), and was then converted into a mass ratio using the Mw of the monomers used.

[0345] The monomer corresponding to repeating unit 1 in Table 1 is a compound having a styrene skeleton, and the positive charge area of ​​the radical cation form is also shown in Table 1. The positive charge area of ​​the radical cation form was determined by carrying out an optimization calculation on the structure of the compound having a styrene skeleton after releasing one electron (radical cation form), and calculating the surface charge density of the optimized structure using the COSMO-RS method. The positive charge area was determined when the surface charge density per unit area was -0.015 e / Å. ２ ~-0.025e / Å ２ The number of regions was summed up. Each calculation was performed using Gaussian 16 as calculation software under the conditions of B3LYP / 6-31+G(d,p). At this time, the solvent effect of water was taken into account by the IEFPCM method.

[0346]

[0347] The structures of the monomers M-1 to M-16, Ma-1 to Ma-3, Mb-1 to Mb-3, Mr-1, and Mr-2 corresponding to the repeating units constituting the resins shown in Table 1 are shown below.

[0348]

[0349]

[0350] Synthesis Example 1 Synthesis of Resin P-4 Cyclohexanone (11.68 g) was placed in a three-neck flask under a nitrogen stream and heated to 85°C. To this was added dropwise over 6 hours: parahydroxystyrene (M-4) (9.77 g), 2-oxohexahydro-2H-3,5-methanocyclopenta[b]furan-6-yl methacrylate 5-methacryloyloxy-2,6-norbornane carbolactone (Mb-1) (5.00 g), 1-methylcyclopentyl methacrylate (Ma-1) (10.0 g), and a solution prepared by mixing 4.5 g of a 20% by mass cyclohexanone solution of polymerization initiator V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 2.17 g) and cyclohexanone (39.63 g). After completion of the dropwise addition, the mixture was allowed to react at 85°C for an additional 2 hours. After cooling, the reaction mixture was added dropwise to a mixture of methanol and water over 20 minutes, and the precipitate was collected by filtration and dried to obtain Resin P-4 (8.76 g).

[0351] [Photoacid Generator (B)] The structures of the photoacid generators (S-1 to S-10, SH-1) shown in Table 2 below are shown below. SH-1 is a comparative compound. Me represents a methyl group.

[0352]

[0353]

[0354]

[0355] [Boron-Containing Compound (C)] The structures of the boron-containing compounds (B-1 to B-9) shown in Table 2 below are shown below.

[0356]

[0357]

[0358] [Acid Diffusion Controller] The structures of the acid diffusion controllers (Q-1 to Q-7) shown in Table 2 below are shown below.

[0359]

[0360]

[0361] [Solvents] The solvents (solvents D-1 to D-6) shown in Table 2 below are as follows: D-1: Propylene glycol monomethyl ether acetate (PGMEA) D-2: Propylene glycol monomethyl ether (PGME) D-3: Cyclohexanone D-4: Ethyl lactate D-5: γ-butyrolactone D-6: Diacetone alcohol

[0362] [Preparation of Resist Compositions] The components shown in Table 2 were mixed to a solids concentration of 1.3% by mass. The resulting mixture was then filtered through a polyethylene filter with a pore size of 0.03 μm to prepare resist compositions (Re-1 to Re-37, Hre-1 to Hre-4). The solids refer to all components other than the solvent. The resulting resist compositions were used in the examples and comparative examples. In the table, the "Content" column indicates the content (% by mass) of each component relative to the total solids in the resist composition. The resin mixing ratio refers to the proportion (mass ratio) of each resin when the total resin is taken as 100. The solvent mixing ratio refers to the proportion (mass ratio) of each solvent when the total solvent is taken as 100.

[0363]

[0364]

[0365] [Pattern Formation and Evaluation (1)] [EUV Exposure, Organic Solvent Development] An underlayer film-forming composition SHB-A940 (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to a silicon wafer and baked at 205°C for 60 seconds to form an underlayer film with a thickness of 20 nm. A resist composition shown in Tables 3 and 4 was applied thereon and baked at 100°C for 60 seconds to form a resist film with a thickness of 30 nm. This resulted in a silicon wafer having a resist film. The silicon wafer having the resist film obtained by the above procedure was subjected to pattern exposure using an EUV exposure apparatus (manufactured by Exitech, Micro Exposure Tool, NA 0.3, Quadrupol, outer sigma 0.68, inner sigma 0.36). A mask with a line:space ratio of 1:1 was used as the reticle. The exposed resist film was baked at 90° C. for 60 seconds, and then developed for 30 seconds with the developer shown in Tables 3 and 4, followed by spin drying to obtain a pattern.

[0366] [Evaluation] <Resolution> The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope (S-9380II manufactured by Hitachi, Ltd.). Under the exposure and development conditions for forming the resist pattern, the exposure dose required to reproduce a mask pattern with a line width of 20 nm was defined as the optimal exposure dose, and when the line width of the line-and-space pattern formed was narrowed by further increasing the exposure dose from the optimal exposure dose, the minimum line width at which the pattern could be resolved without line breaks was defined as the value (nm) indicating resolution. A smaller value indicating resolution indicates that a finer pattern can be resolved, indicating higher resolving power. More specifically, the resolution is preferably 18 nm or less, more preferably 16 nm or less, and even more preferably 14 nm or less.

[0367] <Roughness Performance> Roughness performance was evaluated by line width roughness (LWR performance, nm). The pattern obtained by the above method was observed from above the pattern using a critical dimension scanning electron microscope (SEM (Hitachi, Ltd. S-9380II)). The line width of the pattern was observed at 250 points, and its standard deviation (σ) was determined. The measurement variation in line width was evaluated using 3σ, and the value of 3σ was taken as LWR (nm). The smaller the LWR value, the better the LWR performance. The LWR performance (nm) is preferably 4.2 nm or less, more preferably 4.0 nm or less, even more preferably 3.8 nm or less, even more preferably 3.6 nm or less, particularly preferably 3.4 nm or less, and most preferably 3.2 nm or less.

[0368] The evaluation results are shown in Tables 3 and 4.

[0369]

[0370]

[0371] The developers in Tables 3 and 4 are as follows: K-1: n-butyl acetate K-2: n-butyl acetate / undecane mixed solution (mass ratio: n-butyl acetate / undecane=90 / 10)

[0372] As shown in Tables 3 and 4 above, the resist compositions of the present invention were confirmed to be excellent in resolution and LWR performance. On the other hand, the resist compositions of the comparative examples were insufficient in these respects.

[0373] [Pattern Formation and Evaluation (2)] [EB Exposure, Organic Solvent Development] An underlayer film-forming composition SHB-A940 (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to a silicon wafer and baked at 205°C for 60 seconds to form an underlayer film with a thickness of 20 nm. A resist composition shown in Tables 5 and 6 was applied thereon and baked at 100°C for 60 seconds to form a resist film with a thickness of 30 nm. This resulted in a silicon wafer having a resist film. The silicon wafer having the resist film obtained by the above procedure was subjected to pattern irradiation using an electron beam lithography system (manufactured by Advantest Corporation; F7000S, acceleration voltage 50 keV). The patterning was performed so as to form a 1:1 line and space pattern. The exposed resist film was baked at 90°C for 60 seconds, then developed with the developer shown in Tables 5 and 6 for 30 seconds, and spin-dried to obtain a pattern.

[0374] [Evaluation] The resolution and LWR were evaluated in the same manner as described above.

[0375] The evaluation results are shown in Tables 5 and 6.

[0376]

[0377]

[0378] As shown in Tables 5 and 6, the resist compositions of the present invention were confirmed to have excellent resolution and LWR performance. On the other hand, the resist compositions of the comparative examples were insufficient in these respects.

[0379] According to the present invention, it is possible to provide an actinic ray-sensitive or radiation-sensitive resin composition that is excellent in resolution and roughness performance in forming an ultrafine pattern (for example, a line-and-space pattern with a line width of 20 nm or less, a hole pattern with a hole diameter of 20 nm or less, etc.), a resist film formed from the actinic ray-sensitive or radiation-sensitive resin composition, a pattern formation method that uses the actinic ray-sensitive or radiation-sensitive resin composition, and a method for manufacturing an electronic device.

[0380] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2024-032267) filed on March 4, 2024, the contents of which are incorporated herein by reference.

Claims

1. The positive charge area of ​​the radical cation is 150 Å ２ an actinic ray-sensitive or radiation-sensitive resin composition comprising: a resin (A) having an acid-decomposable group and including a repeating unit derived from a compound having a styrene skeleton of less than 100; an onium salt compound (B) having a cation having at least one fluorine atom and an anion, the onium salt compound generating an acid upon irradiation with actinic rays or radiation; and a boron-containing compound (C).

2. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein the repeating unit derived from the compound having a styrene skeleton is a repeating unit derived from a compound represented by the following general formula (1): In the general formula (1), Rb represents a hydrogen atom or a monovalent organic group. ３ represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group, or a halogenated alkyl group. Ar represents an aromatic ring group. R １ represents a hydroxy group or a carboxy group. ２ represents a substituent other than a hydroxy group or a carboxy group. p is an integer of 1 or more and 9 or less. q is an integer of 0 or more and 8 or less. R １ , R ２ When a plurality of R are present, they may be the same or different. ２ and Rb may be bonded to each other to form a ring.

3. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the resin (A) contains 30 mass% or more of repeating units derived from the compound having a styrene skeleton, based on the total repeating units.

4. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein the boron-containing compound (C) is a compound represented by the following general formula (2C): In general formula (2C), R ５ｃ ~R ８ｃ each independently represents an alkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group. ＋ represents an organic cation or an inorganic cation. m represents an integer of 1 or more. When m represents an integer of 2 or more, a plurality of R ５ｃ may be the same or different. When m is an integer of 2 or more, a plurality of R ６ｃ may be the same or different. When m is an integer of 2 or more, a plurality of R ７ｃ may be the same or different. When m is an integer of 2 or more, a plurality of R ８ｃ may be the same or different. When m is an integer of 2 or more, a plurality of Y ＋ may be the same or different.

5. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein the boron-containing compound (C) is a compound represented by the following general formula (3C): In general formula (3C), R ９ｃ ~R １３ｃ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom. ＋ represents an organic cation or an inorganic cation. m represents an integer of 1 or more. ９ｃ may be the same or different. １０ｃ may be the same or different. １１ｃ may be the same or different. １２ｃ may be the same or different. １３ｃ may be the same or different. When m is an integer of 2 or more, a plurality of Y ＋ may be the same or different.

6. Y ＋ The actinic ray-sensitive or radiation-sensitive resin composition according to claim 4 or 5, wherein is a sulfonium cation or an iodonium cation.

7. Y ＋ The actinic ray-sensitive or radiation-sensitive resin composition according to claim 4 or 5, wherein is a triarylsulfonium cation or a diaryliodonium cation.

8. A resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2.

9. A pattern forming method comprising the steps of: forming a resist film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2; exposing the resist film to light; and developing the exposed resist film with a developer to form a pattern.

10. A method for manufacturing an electronic device, comprising the pattern formation method according to claim 9.