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

Abstract

The present invention provides: an actinic ray-sensitive or radiation-sensitive resin composition including a resin (X) containing repeating units represented by general formula (1) described in the specification and repeating units having interactive groups, an ionic compound (A) that interacts with the interactive groups in the resin (X) and has a non-decomposable organic cation that does not decompose upon irradiation with actinic rays or radiation, an onium salt compound (B) that generates acid upon irradiation with actinic rays or radiation, and a solvent; a resist film; a pattern formation method; and an electronic device manufacturing method including the pattern formation method.

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, an actinic ray-sensitive or radiation-sensitive film, a pattern forming method, and a method for producing an electronic device.

[0002] Since the development of resists for KrF excimer lasers (248 nm), pattern formation methods utilizing chemical amplification have been used to compensate for the loss of sensitivity due to light absorption. For example, in positive-tone chemical amplification methods, a photoacid generator contained in the exposed area decomposes upon light irradiation to generate acid. Then, during a post-exposure bake (PEB) process, the catalytic action of the generated acid changes the alkali-insoluble groups of the resin contained in the actinic ray-sensitive or radiation-sensitive resin composition to alkali-soluble groups, thereby changing the solubility in the developer. Development is then performed, for example, using a basic aqueous solution. This removes the exposed areas to obtain the desired pattern. To achieve miniaturization of semiconductor elements, the wavelength of exposure light sources has become shorter and the numerical aperture (NA) of projection lenses has become higher. Currently, exposure machines using an ArF excimer laser with a wavelength of 193 nm as a light source have been developed. Recently, pattern formation methods using extreme ultraviolet (EUV) light and electron beam (EB) light sources have also been studied. Under these circumstances, various configurations have been proposed as actinic ray-sensitive or radiation-sensitive resin compositions, and recently, compositions containing a resin whose main chain is decomposed or cleaved by exposure have been studied as compositions that can achieve ultra-fine patterns.

[0003] For example, Patent Document 1 describes a positive resist composition containing an ionic compound and a resin that has a repeating unit having an interactive group that interacts with the ionic group in the ionic compound, and whose main chain is decomposed when irradiated with X-rays, electron beams, or extreme ultraviolet rays.

[0004] International Publication No. 2021 / 153466

[0005] In recent years, progress has been made in miniaturizing patterns formed using EUV or electron beams, and further improvements in the performance of resist compositions are required, particularly in terms of resolution and critical dimension uniformity (CDU), which indicates the uniformity of pattern dimensions within a wafer surface during pattern formation.

[0006] An object of the present invention is to provide an actinic ray-sensitive or radiation-sensitive resin composition that is capable of forming a pattern with excellent resolution and CDU in the formation of an ultrafine pattern (for example, a line-and-space pattern with a line width of 25 nm or less, a contact hole pattern with a half pitch of 25 nm or less, etc.) Another object of the present invention is to provide a resist film formed using the actinic ray-sensitive or radiation-sensitive resin composition, a pattern formation method, and a method for manufacturing an electronic device.

[0007] The present inventors have found that the above problems can be solved by the following configuration.

[0008] [1] An actinic ray-sensitive or radiation-sensitive resin composition comprising: a resin (X) containing a repeating unit represented by the following general formula (1) and a repeating unit having an interactive group; an ionic compound (A) having a non-decomposable organic cation that interacts with the interactive group in the resin (X) and is not decomposed by irradiation with actinic rays or radiation; an onium salt compound (B) that generates an acid by irradiation with actinic rays or radiation; and a solvent, wherein the acidity of the conjugate acid of the anion of the ionic compound (A) is different from the acidity of the conjugate acid of the onium salt compound (B).

[0009]

[0010] In the general formula (1), X represents a halogen atom, a fluorinated alkyl group, or a fluorinated cycloalkyl group. ０ represents a hydrogen atom or a monovalent organic group. １ represents a monovalent substituent. ０ and R １ may be bonded to form a ring.

[0011] [2] The actinic ray-sensitive or radiation-sensitive resin composition according to [1], wherein the conjugate acid of the anion of the onium salt compound (B) is stronger than the conjugate acid of the anion of the ionic compound (A). [3] The actinic ray-sensitive or radiation-sensitive resin composition according to [1] or [2], further comprising an onium salt compound (C) that, upon irradiation with actinic rays or radiation, generates an acid weaker than the conjugate acid of the anion of the onium salt compound (B). [4] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [3], wherein the non-decomposable organic cation of the ionic compound (A) is an ammonium cation, a pyridinium cation, an imidazolium cation, or a phosphonium cation.

[0012] [5] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [4], wherein the conjugate acid of the anion of the onium salt compound (B) is an inorganic acid or organic acid stronger than tetrafluoroboric acid. [6] The actinic ray-sensitive or radiation-sensitive resin composition according to [3], wherein the conjugate acid of the anion of the onium salt compound (C) is tetrafluoroboric acid or an inorganic acid or organic acid weaker than tetrafluoroboric acid. [7] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [6], wherein the conjugate acid of the anion of the onium salt compound (B) is hexafluorophosphoric acid, fluoroantimonic acid, a fluorinated alkylsulfonimide, or a fluorinated alkylsulfonic acid.

[0013] [8] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [7], wherein the cation of the onium salt compound (B) is a sulfonium cation or an iodonium cation. [9] The actinic ray-sensitive or radiation-sensitive resin composition according to [3], wherein the conjugate acid of the anion of the onium salt compound (C) is a boric acid compound having an aryl group or a heteroaryl group.

[10] The actinic ray-sensitive or radiation-sensitive resin composition according to [3], wherein the cation of the onium salt compound (C) is a sulfonium cation or an iodonium cation.

[0014]

[11] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to

[10] , wherein the resin (X) has a repeating unit represented by the following general formula (2):

[0015]

[0016] In general formula (2), R ３ represents a hydrogen atom or a monovalent organic group. ４ represents 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. ３ may be bonded to each other to form a ring.

[0017]

[12] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to

[11] , wherein the interactive group in the repeating unit having the interactive group is a phenolic hydroxyl group.

[13] A resist film formed from the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to

[12] .

[0018]

[14] 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

[12] ; exposing the resist film to light; and developing the exposed resist film using a developer.

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

[14] .

[0019] According to the present invention, there is provided an actinic ray-sensitive or radiation-sensitive resin composition that is capable of forming a pattern excellent in resolution and CDU in the formation of an ultrafine pattern (for example, a line-and-space pattern having a line width of 25 nm or less, a contact hole pattern having a half pitch of 25 nm or less, etc.). Furthermore, according to the present invention, there are provided a resist film, a pattern forming method, and a method for manufacturing an electronic device, which use the actinic ray-sensitive or radiation-sensitive resin composition.

[0020] The present invention will be described in detail below. The following description of the constituent elements may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In the present specification, when a group (atomic group) is designated 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. In this specification, "actinic rays" or "radiation" refers to, for example, the emission line spectrum of a mercury lamp, far ultraviolet light typified by excimer lasers, extreme ultraviolet light (EUV: Extreme Ultraviolet), X-rays, and electron beams (EB: Electron Beam). In this specification, "light" refers to actinic rays or radiation. Unless otherwise specified, the term "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, and EUV light, but also drawing using particle beams such as electron beams and ion beams. In this specification, the term "to" is used to mean that the numerical values ​​before and after it are included as the lower and upper limits. The bonding direction of divalent groups expressed 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-. Furthermore, the above compound may be "X-CO-O-Z" or "X-O-CO-Z".

[0021] 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).

[0022] In this specification, the magnitude relationship of the acid strength for the conjugate acids of the anions of the ionic compound (A), onium salt compound (B), and onium salt compound (C) described later can be expressed by category as follows: Inorganic super strong acids, HI > HBr > electron-withdrawing group-substituted sulfonimides > electron-withdrawing group-substituted sulfonic acids > tetrafluoroboric acid > HCl > sulfonic acids > electron-withdrawing group-substituted carboxylic acids, HF > carboxylic acids > boric acid compounds having an aryl group or heteroaryl group > electron-withdrawing group-substituted sulfonamides > electron-withdrawing group-substituted phenolic hydroxyl group-containing compounds > sulfonamides > phenolic hydroxyl group-containing compounds

[0023] In this specification, examples of the electron-withdrawing group include a group selected from the group consisting of a halogen atom (preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), a halogenated hydrocarbon group, an acyl group, an acyloxy group, a cyano group, a nitro group, and a heterocyclic group, and an aryl group substituted with a group selected from the above group.

[0024] The electron-withdrawing group is preferably an electron-withdrawing group having a Hammett's substituent constant σp value of 0.05 or more, more preferably a halogen atom, a halogenated hydrocarbon group, a cyano group, or a nitro group, even more preferably a fluorine atom, a fluorinated hydrocarbon group, a cyano group, or a nitro group, still more preferably a fluorine atom or a fluorinated hydrocarbon group (preferably a fluoroalkyl group having 1 to 10 carbon atoms), and particularly preferably a fluorine atom or a perfluoroalkyl group.

[0025] Here, the Hammett substituent constant σ value is a numerical representation of the effect of a substituent on the acid dissociation equilibrium constant of a substituted benzoic acid, and is a parameter indicating the strength of the electron-withdrawing and electron-donating properties of the substituent. The Hammett substituent constant σp value (hereinafter also simply referred to as "σp value") in this specification means the substituent constant σ when the substituent is located at the para position of the benzoic acid. The σp value of each group in this specification is the value described in the literature "Hansch et al., Chemical Reviews, 1991, Vol. 91, No. 2, 165-195." For groups for which the σp value is not shown in the above literature, the σp value can be calculated using the software "ACD / ChemSketch (ACD / Labs 8.00 Release Product Version: 8.08)" based on the difference between the pKa of benzoic acid and the pKa of a benzoic acid derivative having a substituent at the para position.

[0026] Examples of acids included in each of the above categories are given below. Examples of inorganic super acids include HPF ６ , HSbF ６ , HClO ４ etc.

[0027] Examples of the electron-withdrawing group-substituted sulfonimide include acids having a partial structure represented by the following formula (H-1).

[0028]

[0029] In formula (H-1), R ＸＦ２ represents an electron-withdrawing group, and is preferably a fluorine atom or a perfluoroalkyl group. ＸＦ２ may be bonded to another group of the acid to form a ring. * represents a bond.

[0030] Examples of acids having the partial structure represented by the above formula (H-1) include the following acids.

[0031]

[0032] Examples of the electron-withdrawing group-substituted sulfonic acid include acids having a partial structure represented by the following formula (H-2-1) or formula (H-2-2).

[0033]

[0034] In formula (H-2-1), R ＸＦ１ represents a hydrogen atom or a substituent, provided that two R ＸＦ１ At least one of the two R in formula (H-2-1) represents an electron-withdrawing group. ＸＦ１ may be the same or different. ＸＦ３ represents a hydrogen atom or a substituent. ＸＦ３ may be the same or different, provided that R ＸＦ３ At least one of the groups represents an electron-withdrawing group. * represents a bond.

[0035] R ＸＦ１ , R ＸＦ３ The substituent is not particularly limited, and examples thereof include an electron-withdrawing group, an alkyl group (which may be linear or branched, and preferably has 1 to 15 carbon atoms), an alkoxy 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), an aryl group (which may be monocyclic or polycyclic, and preferably has 6 to 20 carbon atoms), and a hydroxy group.

[0036] Examples of acids having a partial structure represented by the above formula (H-2-1) or (H-2-2) include the following acids.

[0037]

[0038] Examples of sulfonic acids include acids having a partial structure represented by the following formula (H-3-1) or formula (H-3-2).

[0039]

[0040] In formula (H-3-1), R Ｘ２ Each of the two R in formula (H-3-1) independently represents a hydrogen atom or a substituent other than an electron-withdrawing group. Ｘ２ may be the same or different. Ｘ３ represents a hydrogen atom or a substituent other than an electron-withdrawing group. Ｘ３may be the same or different. * represents a bond.

[0041] R Ｘ２ Examples of the substituent other than the electron-withdrawing group represented by the formula (I) include an alkyl group not containing a fluorine atom (which may be linear or branched, and preferably has 1 to 15 carbon atoms) and a cycloalkyl group not containing a fluorine atom (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms).

[0042] R Ｘ３ Examples of the substituent other than the electron-withdrawing group represented by the formula (I) include an alkyl group not containing a fluorine atom (which may be linear or branched, and preferably has 1 to 15 carbon atoms), a cycloalkyl group not containing a fluorine atom (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms), a hydroxy group, and an alkoxy group (which may be linear or branched, and preferably has 1 to 15 carbon atoms).

[0043] Examples of acids having a partial structure represented by the above formula (H-3-1) or (H-3-2) include the following acids.

[0044]

[0045] Examples of the electron-withdrawing group-substituted carboxylic acid include acids having a partial structure represented by the following formula (H-4-1) or formula (H-4-2).

[0046]

[0047] In formula (H-4-1), R ＸＦ１ represents a hydrogen atom or a substituent, provided that two R ＸＦ１ At least one of the two R in formula (H-4-1) represents an electron-withdrawing group. ＸＦ１ may be the same or different. ＸＦ３ represents a hydrogen atom or a substituent. ＸＦ３ may be the same or different, provided that R ＸＦ３ At least one of these represents an electron-withdrawing group. * represents a bond. R ＸＦ１ , R ＸＦ３The substituent is not particularly limited, and examples thereof include an electron-withdrawing group, an alkyl group (which may be linear or branched, and preferably has 1 to 15 carbon atoms), an alkoxy 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), an aryl group (which may be monocyclic or polycyclic, and preferably has 6 to 20 carbon atoms), and a hydroxy group.

[0048] Examples of acids having a partial structure represented by the above formula (H-4-1) or (H-4-2) include the following acids.

[0049]

[0050] Examples of the carboxylic acid include acids having a partial structure represented by the following formula (H-5-1) or formula (H-5-2).

[0051]

[0052] In formula (H-5-1), R Ｘ２ Each of the two R in formula (H-5-1) independently represents a hydrogen atom or a substituent other than an electron-withdrawing group. Ｘ２ may be the same or different. Ｘ３ represents a hydrogen atom or a substituent other than an electron-withdrawing group. Ｘ３ may be the same or different. * represents a bond.

[0053] R Ｘ２ The substituents other than the electron-withdrawing group in R are not particularly limited, but examples thereof include an alkyl group not containing a fluorine atom (which may be linear or branched, and preferably has 1 to 15 carbon atoms) and a cycloalkyl group not containing a fluorine atom (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms). Ｘ３The substituent other than the electron-withdrawing group is not particularly limited, and examples thereof include an alkyl group not containing a fluorine atom (which may be linear or branched, and preferably has 1 to 15 carbon atoms), a cycloalkyl group not containing a fluorine atom (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms), a hydroxy group, and an alkoxy group (which may be linear or branched, and preferably has 1 to 15 carbon atoms).

[0054] Examples of acids having a partial structure represented by the above formula (H-5-1) or (H-5-2) include the following acids.

[0055]

[0056] Examples of the boric acid compound having an aryl group or a heteroaryl group include tetraphenylborate, tetraimidazolylborate, tetrafuranylborate, etc. Also included are conjugate acids of the anions represented by formula (B10) described below as the anions of the boric acid compound having an aryl group or a heteroaryl group.

[0057] Examples of the electron-withdrawing group-substituted sulfonamide include acids having a partial structure represented by the following formula (H-6-1) or (H-6-2).

[0058]

[0059] In formula (H-6-1) and formula (H-6-2), R ＸＦ２ R each independently represents an electron-withdrawing group. ＸＦ２ may be bonded to another group of the acid to form a ring. * represents a bond.

[0060] Examples of acids having a partial structure represented by the above formula (H-6-1) or (H-6-2) include the following acids.

[0061]

[0062] Examples of the electron-withdrawing group-substituted phenolic hydroxyl group-containing compound include acids having a partial structure represented by the following formula (H-7).

[0063]

[0064] In formula (H-7), R ＸＦ３ represents a hydrogen atom or a substituent. ＸＦ３ may be the same or different, provided that R ＸＦ３ At least one of these represents an electron-withdrawing group. * represents a bond. R ＸＦ３ The substituent is not particularly limited, and examples thereof include an electron-withdrawing group, an alkyl group (which may be linear or branched, and preferably has 1 to 15 carbon atoms), an alkoxy 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), an aryl group (which may be monocyclic or polycyclic, and preferably has 6 to 20 carbon atoms), and a hydroxy group.

[0065] Examples of acids having a partial structure represented by the above formula (H-7) include the following acids.

[0066]

[0067] Examples of sulfonamides include acids having a partial structure represented by the following formula (H-8-1) or formula (H-8-2).

[0068]

[0069] In formula (H-8-1) and formula (H-8-2), R Ｘ１ R each independently represents a substituent other than an electron-withdrawing group. Ｘ１ may be bonded to another group of the acid to form a ring. * represents a bond.

[0070] R Ｘ１ The substituent other than the electron-withdrawing group is not particularly limited, and examples thereof include an alkyl group not containing a fluorine atom (which may be linear or branched, and preferably has 1 to 15 carbon atoms) and a cycloalkyl group not containing a fluorine atom (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms).

[0071] Examples of acids having a partial structure represented by the above formula (H-8-1) or (H-8-2) include the following acids.

[0072]

[0073] Examples of the phenolic hydroxyl group-containing compound include acids having a partial structure represented by the following formula (H-9).

[0074]

[0075] In formula (H-9), R Ｘ３ represents a hydrogen atom or a substituent other than an electron-withdrawing group. Ｘ３ may be the same or different. * represents a bond.

[0076] R Ｘ３ The substituent other than the electron-withdrawing group is not particularly limited, and examples thereof include an alkyl group not containing a fluorine atom (which may be linear or branched, and preferably has 1 to 15 carbon atoms) and a cycloalkyl group not containing a fluorine atom (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms).

[0077] Examples of acids having a partial structure represented by the above formula (H-9) include the following acids.

[0078]

[0079] When an acid compound has a plurality of acidic groups, the acid strength of the acidic group having the stronger acid strength is compared with that of other acids.

[0080] The above magnitude relationship is set based on data in the following publicly known documents.

[0081] Organic Chemistry Data Collection: Acid Constants in Aqueous Solutions <http: / / organodata.wiki.fc2.com / wiki / > (hereinafter simply referred to as "Organic Chemistry Data Collection") Hans Reich, April 11, 2022, ACS Division of Organic Chemistry, <https: / / organicchemistrydata.org / hansreich / resources / pka / pka_data / pka-compilation-reich-bordwell.pdf> (hereinafter simply referred to as "Bordwell pKa Table") https: / / ja. wikipedia.org / wiki / %E9%85%B8%E8%A7%A3%E9%9B%A2%E5%AE%9A%E6%95%B0 (hereinafter also referred to simply as "wikipedia / acid dissociation constant")

[0082] Furthermore, the magnitude relationship of the acid strength of multiple acids in the same category can also be determined by comparing their acid dissociation constants (pKa) in aqueous solution. Specifically, the pKa in aqueous solution is a value determined by calculation using the following software package 1 based on a database of Hammett's substituent constants and publicly known literature values. All pKa values ​​described in this specification are values ​​determined by calculation using this software package.

[0083] Software package 1: Advanced Chemistry Development (ACD / Labs) Software V8.14 for Solaris (1994-2007 ACD / Labs).

[0084] 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.

[0085] When it is not possible to calculate values ​​based on a database of Hammett's substituent constants and publicly known literature values ​​using Software Package 1, values ​​obtained by Gaussian 16 based on DFT (density functional theory) are used. Furthermore, when it is not possible to calculate pKa in aqueous solution, "pKa in dimethyl sulfoxide (DMSO) solution" is used.

[0086] In this specification, the magnitude relationship of acid strength will be referred to in the following order (1) to (3) ((1) has the first priority, and (2) has the second priority): (1) "Definition of magnitude relationship by category" mentioned above (2) Software package 1 (3) Molecular orbital calculation method

[0087] Note that values ​​are not compared between different values ​​in (1) to (3) above (for example, values ​​are compared using values ​​determined in (2) and (3)). Each category can be determined by (1) above (defining the magnitude relationship for each category), and for each category, the magnitude relationship of acids can be determined by, for example, (2) (software package 1).

[0088] In this specification, examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0089] 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.

[0090] [Actinic ray- or radiation-sensitive resin composition] The actinic ray- or radiation-sensitive resin composition (hereinafter also referred to as "resist composition") of the present invention comprises: a resin (X) containing a repeating unit represented by the following general formula (1) and a repeating unit having an interactive group; an ionic compound (A) having a non-decomposable organic cation that interacts with the interactive group in the resin (X) and is not decomposed by irradiation with actinic rays or radiation; an onium salt compound (B) that generates an acid by irradiation with actinic rays or radiation; and a solvent, wherein the acidity of the conjugate acid of the anion of the ionic compound (A) is different from the acidity of the conjugate acid of the onium salt compound (B).

[0091]

[0092] In the general formula (1), X represents a halogen atom, a fluorinated alkyl group, or a fluorinated cycloalkyl group. ０ represents a hydrogen atom or a monovalent organic group. １ represents a monovalent substituent. ０ and R １ may be bonded to form a ring.

[0093] The resist composition of the present invention, having the above-described structure, is capable of forming an ultrafine pattern that exhibits excellent resolution and CDU. The reason for this is not fully understood, but the inventors speculate as follows.

[0094] The resin (X) contained in the resist composition of the present invention is a resin whose main chain decomposes upon irradiation with actinic rays or radiation. This is due to the fact that the resin (X) has a repeating unit represented by the general formula (1) above. When a resist film is formed using the resist composition of the present invention and irradiated with actinic rays or radiation, the main chain is cleaved in the exposed areas, resulting in a lower molecular weight and increased solubility in a developer. In other words, a difference in dissolution rate in a developer (so-called dissolution contrast) occurs between the unexposed and exposed areas. Because the resin (X) is lowered in molecular weight, it is believed that the solubility in an alkaline developer and the solubility in an organic developer are increased in the exposed areas.

[0095] Furthermore, the resin (X) has a repeating unit having an interactive group. The ionic compound (A) contained in the resist composition of the present invention has a group (ionic group) that interacts with the interactive group and also has a non-decomposable organic cation. In a resist film formed using the resist composition of the present invention, before exposure, the ionic group and the interactive group are thought to interact to form an association structure similar to a salt, resulting in poor solubility in a developer. Upon irradiation with actinic rays or radiation, the onium salt compound (B) contained in the resist composition of the present invention decomposes in the exposed areas to generate an acid. The generated acid acts on the ionic compound (A), weakening the interaction between the ionic group and the interactive group, thereby dissolving the association structure and increasing the solubility of the exposed areas in the developer. In other words, a further solubility contrast is created between the unexposed and exposed areas. It is thought that the solubility of the exposed areas increases in both alkaline and organic developers.

[0096] In the present invention, the weakening of the interaction is achieved not by the exposure light but by the action of the acid generated by exposure, which prevents unintended weakening of the interaction due to slight leakage of exposure light in the unexposed area adjacent to the exposed area, thereby making it easier to achieve dissolution contrast at the boundary between the exposed and unexposed areas.

[0097] In this way, by containing the resin (X), the ionic compound (A), and the onium salt compound (B), the resist composition of the present invention is able to significantly improve the dissolution contrast between exposed and unexposed areas, and is thought to be able to form patterns that have excellent resolution and CDU, even when forming ultrafine patterns. Hereinafter, the term "excellent effects of the present invention" refers to a pattern formed from a resist composition having better resolution and / or a pattern formed from a resist composition having better CDU.

[0098] First, the various components contained in the resist composition will be described below.

[0099] [Resin (X)] The resist composition of the present invention contains a resin (hereinafter also referred to as resin (X)) that contains a repeating unit represented by the following general formula (1) and a repeating unit having an interactive group.

[0100] Resin (X) is a so-called main chain scission polymer, the main chain of which is decomposed (the main chain is scissioned) upon irradiation with actinic rays or radiation. Resin (X) is preferably a polymer whose main chain is decomposed upon irradiation with X-rays, electron beams, or extreme ultraviolet rays, and more preferably a polymer whose main chain is decomposed upon irradiation with electron beams or extreme ultraviolet rays.

[0101] Resin (X) is preferably a copolymer containing a repeating unit represented by the following general formula (1), which is a repeating unit that enables Resin (X) to function as a main-chain scission polymer, and a repeating unit represented by the below-described general formula (2). Resin (X) may be a random copolymer, a block copolymer, or an alternating copolymer, and is more preferably an alternating copolymer.

[0102] <Repeating Unit Having an Interactive Group> The resin (X) has a repeating unit having an interactive group. The interactive group acts as a group that interacts with the ionic group in the ionic compound (A) described below. Examples of the interactive group include a hydroxy group (such as an alcoholic hydroxy group and a phenolic hydroxy group), a carboxyl group, a sulfonic acid group, an amide group, and a sulfonamide group. The phenolic hydroxy group refers to a hydroxy group substituted on a ring atom of an aromatic ring (aromatic hydrocarbon ring and aromatic heterocycle). The amide group is not particularly limited, and examples thereof include -C(=O)-NHR Ｐ (R Ｐ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

[0103] The aromatic ring to which the hydroxyl group in the phenolic hydroxyl group is bonded is not particularly limited, and may be an aromatic hydrocarbon ring or an aromatic heterocycle. The aromatic ring may be a monocycle or a polycycle. Specific examples include the groups exemplified as aromatic rings in the aromatic ring group possessed by Ar in the general formula (2) described below.

[0104] The interactive group is preferably at least one group selected from a phenolic hydroxyl group, a carboxyl group, a sulfonamide group, and a sulfonic acid group, more preferably at least one group selected from a phenolic hydroxyl group and a carboxyl group, and even more preferably a phenolic hydroxyl group.

[0105] The repeating unit having an interactive group may be a repeating unit represented by the general formula (1) described below, a repeating unit represented by the general formula (2), or a repeating unit other than the general formulas (1) and (2), but is preferably at least one of the repeating unit represented by the general formula (1) and the repeating unit represented by the general formula (2), and more preferably the repeating unit represented by the general formula (2). The specific structure of the repeating unit will be described later.

[0106] In resin (X), the content of the repeating unit having an interactive group is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 40 mol% or more, based on the total repeating units. The upper limit is, for example, preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 80 mol% or less, and particularly preferably 60 mol% or less, based on the total repeating units. Resin (X) may contain one type of repeating unit having an interactive group, or two or more types. When two or more types are contained, the total content is preferably within the above-mentioned preferred content range.

[0107] <Repeating unit represented by general formula (1)>

[0108]

[0109] In the general formula (1), X represents a halogen atom, a fluorinated alkyl group, or a fluorinated cycloalkyl group. ０ represents a hydrogen atom or a monovalent organic group. １ represents a monovalent substituent. ０ and R １ may be bonded to form a ring.

[0110] In the general formula (1), X represents a halogen atom, a fluorinated alkyl group, or a fluorinated cycloalkyl group.

[0111] Examples of the halogen atom represented by X 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.

[0112] The alkyl group in the fluorinated alkyl group represented by X may be a linear or branched alkyl group having 1 to 6 carbon atoms, with methyl and ethyl groups being preferred.

[0113] The cycloalkyl group in the fluorinated cycloalkyl group represented by X may be a monocyclic or polycyclic cycloalkyl group having 5 to 20 carbon atoms, preferably 5 to 15 carbon atoms.

[0114] The above group represented by X may further have a substituent, if possible. Examples of the substituent include the substituent T described below.

[0115] From the viewpoint of usefulness as a main chain decomposition-type resin contained in an actinic ray-sensitive or radiation-sensitive resin composition, X preferably represents a halogen atom, more preferably a chlorine atom, a bromine atom, or an iodine atom, and even more preferably a chlorine atom.

[0116] In general formula (1), R ０ represents a hydrogen atom or a monovalent organic group. ０ The monovalent organic group is not particularly limited, but may be, for example, an alkyl group. The alkyl group may be either linear or branched, and may be, for example, an alkyl group having 1 to 20 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. ０ preferably represents a hydrogen atom.

[0117] In general formula (1), R １ represents a monovalent substituent. １ is preferably a group represented by the following general formula (1a): １ -R ２ (1a) In general formula (1a), L １ is —O— or —NRＸ - represents. Ｘ represents a hydrogen atom or a monovalent organic group. ２ represents a monovalent organic group.

[0118] R Ｘ The monovalent organic group is not particularly limited, but examples thereof include monovalent organic groups having 1 to 20 carbon atoms. As the monovalent organic group, an alkyl group or a cycloalkyl group is preferred. 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. The cycloalkyl group may be monocyclic or polycyclic, and is preferably a cycloalkyl group having 5 to 20 carbon atoms, and more preferably a cycloalkyl group having 5 to 15 carbon atoms. Furthermore, each of the above groups may further have a substituent, if possible. R Ｘ preferably represents a hydrogen atom.

[0119] R ２ represents a monovalent organic group. ２ The monovalent organic group represented by the formula (I) is not particularly limited, and examples thereof include the groups exemplified as the organic group W below.

[0120] (Organic Group W) Examples of the organic group W include alkyl groups, cycloalkyl groups, alkenyl groups, cycloalkenyl groups, alkynyl groups, cycloalkynyl groups, aryl groups, heteroaryl groups, aralkyl groups, cyano groups, alkoxy groups, aryloxy groups, heterocyclic oxy groups, acyl groups (alkylcarbonyl groups or arylcarbonyl groups), acyloxy groups (alkylcarbonyloxy groups or arylcarbonyloxy groups), carbamoyloxy groups, alkoxycarbonyloxy groups, aryloxycarbonyloxy groups, alkylthio groups, arylthio groups, heterocyclic thio groups, alkyl or arylsulfinyl groups, alkyl or arylsulfonyl groups, aryloxycarbonyl groups, alkoxycarbonyl groups, aryl or heterocyclic azo groups, sulfonamide groups, imide groups, acylamino groups, carbamoyl groups, and lactone groups.In addition, each of the above groups may further have a substituent, if possible.For example, an alkyl group that may have a substituent is also included as one form of the organic group W. The substituent is not particularly limited, and examples thereof include one or more of the groups exemplified above as the organic group W, a halogen atom, a nitro group, a primary to tertiary amino group, a phosphino group, a phosphinyl group, a phosphinyloxy group, a phosphinylamino group, a phosphono group, a silyl group, a hydroxy group, a carboxy group, a sulfonic acid group, and a phosphate group (hereinafter, these are referred to as "substituents T"). The number of carbon atoms contained in the organic group W is, for example, 1 to 20. The number of atoms other than hydrogen atoms contained in the organic group W is, for example, 1 to 30.

[0121] The number of carbon atoms in the alkyl group exemplified as the organic group W is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6. The alkyl group may be either linear or branched. Examples of the alkyl group include linear or branched alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a t-butyl group, and an n-hexyl group. In the alkyl group which may have a substituent, the substituent which the alkyl group may have is not particularly limited, and examples thereof include the groups exemplified above for the substituent T. It is also preferable that the alkyl group has the above-mentioned interactive group as a substituent.

[0122] The alkyl group moiety in the alkoxy group (including the alkoxy group moiety in a substituent containing an alkoxy group (for example, an alkoxycarbonyloxy group)) exemplified in the organic group W, the alkyl group moiety in the aralkyl group, the alkyl group moiety in the alkylcarbonyl group, the alkyl group moiety in the alkylcarbonyloxy group, the alkyl group moiety in the alkylthio group, the alkyl group moiety in the alkylsulfinyl group, and the alkyl group moiety in the alkylsulfonyl group are preferably the above-mentioned alkyl groups. Furthermore, in the alkoxy group which may have a substituent, the aralkyl group which may have a substituent, the alkylcarbonyloxy group which may have a substituent, the alkylthio group which may have a substituent, the alkylsulfinyl group which may have a substituent, and the alkylsulfonyl group which may have a substituent, examples of the substituent that the alkoxy group, aralkyl group, alkylcarbonyloxy group, alkylthio group, alkylsulfinyl group, and alkylsulfonyl group may have include the same examples as the substituent in the alkyl group which may have a substituent.

[0123] Examples of the cycloalkyl group exemplified in the organic group W 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. The number of carbon atoms in the cycloalkyl group is preferably 5 to 20, and more preferably 5 to 15. In the cycloalkyl group which may have a substituent, examples of the substituent which the cycloalkyl group may have include the same as the examples of the substituent in the alkyl group which may have a substituent.

[0124] The alkenyl group exemplified in the organic group W may be either linear or branched. The number of carbon atoms in the alkenyl group is preferably 2 to 20. In the optionally substituted alkenyl group, examples of the substituent that the alkenyl group may have include the same examples as the substituents in the optionally substituted alkyl group. The number of carbon atoms in the cycloalkenyl group exemplified in the organic group W is preferably 5 to 20. In the optionally substituted cycloalkenyl group, examples of the substituent that the cycloalkenyl group may have include the same examples as the substituents in the optionally substituted alkyl group.

[0125] The alkynyl group exemplified in the organic group W may be either linear or branched. The number of carbon atoms in the alkynyl group is preferably 2 to 20. In the alkynyl group which may have a substituent, examples of the substituent that the alkynyl group may have include the same as the substituents in the alkyl group which may have a substituent. The number of carbon atoms in the cycloalkynyl group exemplified in the organic group W is preferably 5 to 20. In the cycloalkynyl group which may have a substituent, examples of the substituent that the cycloalkynyl group may have include the same as the substituents in the alkyl group which may have a substituent.

[0126] The aryl group exemplified in the organic group W may be either a monocyclic or polycyclic (e.g., 2 to 6 rings, etc.) unless otherwise specified. The number of ring atoms in the aryl group is preferably 6 to 15, more preferably 6 to 10. The aryl group is preferably a phenyl group, a naphthyl group, or an anthryl group, and more preferably a phenyl group. In the aryl group which may have a substituent, examples of the substituent which the aryl group may have include the same examples as the substituent in the alkyl group which may have a substituent. Furthermore, among the groups exemplified in the organic group W, examples of the aryl group moiety in the substituent containing an aryl group (e.g., an aryloxy group) include the same examples as the aryl group exemplified in the organic group W.

[0127] The heteroaryl group exemplified as the organic group W may be either a monocyclic or polycyclic (e.g., 2 to 6 rings, etc.) unless otherwise specified. The number of heteroatoms contained in the heteroaryl group as ring atoms is, for example, 1 to 10. Examples of the heteroatom include a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom. The number of ring atoms in the heteroaryl group is preferably 5 to 15. In the heteroaryl group which may have a substituent, examples of the substituent which the heteroaryl group may have include the same as the substituents in the alkyl group which may have a substituent.

[0128] The heterocycle exemplified in the organic group W intends a ring containing a heteroatom as a ring member atom, and unless otherwise specified, may be either an aromatic heterocycle or an aliphatic heterocycle, and may be either a monocycle or a polycycle (e.g., 2-6 rings, etc.). The number of heteroatoms contained in the heterocycle as ring member atoms is, for example, 1 to 10. Examples of the heteroatom include a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom. The number of ring member atoms in the heterocycle is preferably 5 to 15. In the heterocycle which may have a substituent, examples of the substituent which the heterocycle may have include the same as the substituents in the alkyl group which may have a substituent.

[0129] The lactone group exemplified as the organic group W is preferably a 5- to 7-membered lactone group, and more preferably a 5- to 7-membered lactone ring to which another ring structure is condensed so as to form a bicyclo structure or a spiro structure. In the lactone group which may have a substituent, examples of the substituent which the lactone group may have are the same as those of the substituent in the alkyl group which may have a substituent.

[0130] R ２ Among these, alkyl groups, cycloalkyl groups, and aryl groups are preferred, and alkyl groups having 1 to 6 carbon atoms, cyclohexyl groups, and phenyl groups are more preferred.

[0131] R ０ and R １may be bonded to each other to form a ring. ０ and R １ The ring formed by bonding together is not particularly limited and may be either a monocyclic ring or a polycyclic ring. The ring may contain heteroatoms such as oxygen atoms, nitrogen atoms, and sulfur atoms, and / or carbonyl carbon atoms as ring member atoms. Among these, the ring is preferably a 5- or 6-membered ring.

[0132] The repeating unit represented by the above general formula (1) is preferably represented by the following general formula (1-1), and more preferably represented by the following general formula (1-2).

[0133]

[0134] In the general formula (1-1), X represents a halogen atom, a fluorinated alkyl group, or a fluorinated cycloalkyl group. ０ represents a hydrogen atom or a monovalent organic group. １ is —O— or —NR Ｘ - represents. Ｘ represents a hydrogen atom or a monovalent organic group. ２ represents a monovalent organic group. ０ and R ２ may be bonded to form a ring.

[0135] X and R ０ represents X and R in general formula (1). ０ The same applies to preferred examples. １ and R ２ represents L in general formula (1a). １ and R ２ The same applies to preferred examples.

[0136]

[0137] In general formula (1-2), X １ represents a halogen atom, R ２ represents a monovalent organic group.

[0138] X １ Examples of the halogen atom represented by R include the halogen atom represented by X in general formula (1), and preferred examples are also the same. ２represents R in general formula (1a). ２ The same applies to preferred examples.

[0139] Specific examples of the monomers constituting the repeating unit represented by formula (1) are listed below, but the present invention is not limited to these.

[0140]

[0141]

[0142]

[0143] The repeating unit represented by general formula (1) may be used alone or in combination of two or more. The content of the repeating unit represented by general formula (1) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 40 mol% or more, relative to the total repeating units constituting the resin (X). The upper limit is, for example, preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 80 mol% or less, and particularly preferably 60 mol% or less. As described above, the repeating unit represented by general formula (1) may be used alone or in combination of two or more. When two or more types are used, it is preferable that the total content is within the above-mentioned preferred content range.

[0144] <Repeating unit represented by general formula (2)> From the viewpoint of etching resistance, the resin (X) preferably has a repeating unit represented by the following general formula (2) in addition to the repeating unit represented by the above-mentioned general formula (1).

[0145]

[0146] In general formula (2), R ３ represents a hydrogen atom or a monovalent organic group. ４ represents 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. ３ may be bonded to each other to form a ring.

[0147] In general formula (2), R ３ represents a hydrogen atom or a monovalent organic group. ３ The monovalent organic group represented by is not particularly limited, but can be, for example, an alkyl group. The alkyl group may be either linear or branched, and can be, for example, an alkyl group having 1 to 20 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. ３ preferably represents a hydrogen atom.

[0148] In general formula (2), R ４ represents 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.

[0149] R ４ 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.

[0150] R ４ 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.

[0151] R ４ 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.

[0152] R ４ 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.

[0153] R ４ 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.

[0154] R ４ 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.

[0155] R ４ 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.

[0156] R ４ 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.

[0157] R ４ is preferably an alkyl group, more preferably a methyl group.

[0158] In the general formula (2), 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.

[0159] 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.

[0160] 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.

[0161] The aromatic ring group of Ar may further have a substituent. The substituent is not particularly limited, but may be any of the above-mentioned substituent T, the above-mentioned interactive group, and R in the general formula (2-1) described later.５ Examples of the group include a group represented by the following formula:

[0162] Ar and R ３ Ar and R may be bonded to each other to form a ring. ３ The ring formed by bonding together is not particularly limited and may be either a monocyclic ring or a polycyclic ring (excluding Ar itself). The ring may contain heteroatoms such as oxygen atoms, nitrogen atoms, and sulfur atoms, and / or carbonyl carbon atoms as ring member atoms. Among these, the ring is preferably a 5- or 6-membered ring.

[0163] The repeating unit represented by the above general formula (2) is preferably represented by the following general formula (2-1).

[0164]

[0165] In general formula (2-1), R ３ represents a hydrogen atom or a monovalent organic group. ４ represents 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. １ represents an aromatic ring group. ５ represents an alkyl group, an alkoxy group, an acyloxy group, a halogen atom, a hydroxy group, a carboxy group, or a halogenated alkyl group. p is an integer of 0 to 5. ５ When a plurality of R are present, they may be the same or different. ５ and R ３ may be bonded to each other to form a ring.

[0166] R ３ , and R ４ is R in general formula (2) ３ , and R ４ The same applies to preferred examples.

[0167] In general formula (2-1), Ar １ represents an aromatic ring group. １ The aromatic ring in the aromatic ring group may be an aromatic hydrocarbon ring or an aromatic heterocyclic ring.

[0168] 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.

[0169] 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.

[0170] In general formula (2-1), R ５ represents an alkyl group, an alkoxy group, an acyloxy group, a halogen atom, a hydroxy group, a carboxy group, or a halogenated alkyl group.

[0171] R ５ Examples of the alkyl group and alkoxy group represented by R include the alkyl group and alkoxy group described above as the organic group W, and preferred examples are also the same. ５ Examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is more preferred. ５ Examples of the alkyl group in the acyloxy group (alkylcarbonyloxy group or arylcarbonyloxy group) represented by the formula (I) include the alkyl groups described above as the organic group W, and preferred examples are also the same. Examples of the aryl group include the alkyl groups described above as the organic group W, and preferred examples are also the same. ５ The alkyl group in the halogenated alkyl group represented by R ４ 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, with a chlorine atom being more preferred.

[0172] R ５The above group represented by the formula (I) may further have a substituent, if possible. Examples of the substituent include the above-mentioned substituent T. It is also preferable that the above-mentioned interactive group be included as a substituent.

[0173] R ５ is preferably a hydroxy group, a carboxy group, or an alkoxy group having 1 to 6 carbon atoms, and from the viewpoint of the interactivity with the ionic group in the ionic compound (A), is more preferably a hydroxy group or a carboxy group, and is even more preferably a hydroxy group.

[0174] In the general formula (2-1), p is an integer of 0 or more and 5 or less, preferably an integer of 0 to 3, and more preferably an integer of 1 or 2.

[0175] R ５ and R ３ may be bonded to each other to form a ring. ５ and R ３ The ring formed by bonding together is not particularly limited and may be either a monocyclic ring or a polycyclic ring. The ring may contain heteroatoms such as oxygen atoms, nitrogen atoms, and sulfur atoms, and / or carbonyl carbon atoms as ring member atoms. Among these, the ring is preferably a 5- or 6-membered ring.

[0176] The repeating unit represented by the above general formula (2) is preferably represented by the following general formula (2-2).

[0177]

[0178] In general formula (2-2), R ３ represents a hydrogen atom or a monovalent organic group. ４ represents 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. ５ represents an alkyl group, an alkoxy group, an acyloxy group, a halogen atom, a hydroxy group, a carboxy group, or a halogenated alkyl group. p is an integer of 0 to 5. ５ When a plurality of R are present, they may be the same or different. ５ and R ３may be bonded to each other to form a ring.

[0179] R ３ , R ４ , R ５ and p is R in general formula (2-1). ３ , R ４ , R ５ and p have the same meanings, and preferred examples are also the same.

[0180] Specific examples of the monomer that constitutes the repeating unit represented by formula (2) are listed below, but are not limited to these: Me represents a methyl group.

[0181]

[0182]

[0183] The repeating unit represented by general formula (2) may be used alone or in combination of two or more. The content of the repeating unit represented by general formula (2) is preferably 30 mol% or more, more preferably 40 mol% or more, and even more preferably 45 mol% or more, based on the total repeating units constituting resin (X). The upper limit is, for example, preferably 70 mol% or less, more preferably 60 mol% or less, even more preferably 55 mol% or less, and particularly preferably 53 mol% or less. As described above, the repeating unit represented by general formula (2) may be used alone or in combination of two or more. When two or more types are used, the total content is preferably within the above-mentioned preferred content range.

[0184] <Other Repeating Units> The resin (X) may contain repeating units other than the repeating units described above, as long as the effects of the present invention are not impaired. Specifically, for example, the resin (X) may contain a repeating unit represented by the following general formula (3):

[0185]

[0186] In general formula (3), R ６ represents a hydrogen atom or a monovalent organic group. ７represents a hydrogen atom, an alkyl group, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, or an alkyl ester group. ８ represents a monovalent substituent. ６ and R ８ may be bonded to form a ring.

[0187] In general formula (3), R ６ represents a hydrogen atom or a monovalent organic group. ６ The monovalent organic group represented by R in general formula (1) ０ The same applies to the preferred examples of R ６ preferably represents a hydrogen atom.

[0188] In general formula (3), R ７ represents a hydrogen atom, an alkyl group, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, or an alkyl ester group. ７ The alkyl group, alkylsulfonyl group, alkoxy group, acyl group, and alkyl ester group represented by R ４ Examples of the alkyl group include an alkyl group, an alkylsulfonyl group, an alkoxy group, an acyl group, and an alkyl ester group, and preferred examples are also the same.

[0189] R ７ is preferably an alkyl group, more preferably a methyl group.

[0190] In general formula (3), R ８ represents a monovalent substituent. ８ The monovalent substituent represented by is R in general formula (1). １ Preferred examples are also the same.

[0191] The repeating unit represented by the above general formula (3) is preferably represented by the following general formula (3-1), and more preferably represented by the following general formula (3-2).

[0192]

[0193] In general formula (3-1), R ６ and R ７ is R in general formula (3)６ and R ７ The same applies to preferred examples. ２ is —O— or —NR Ｘ - represents. Ｘ represents a hydrogen atom or a monovalent organic group. ９ represents a monovalent organic group. ６ and R ９ may be bonded to form a ring.

[0194] L ２ and R ９ respectively represent L in general formula (1a). １ and R ２ The same applies to preferred examples.

[0195]

[0196] In general formula (3-2), R ７ is R in general formula (3) ７ The same applies to preferred examples. ９ represents a monovalent organic group.

[0197] R ９ represents R in general formula (1a). ２ The same applies to preferred examples.

[0198] Specific examples of the monomer that constitutes the repeating unit represented by formula (3) are listed below, but the present invention is not limited to these.

[0199]

[0200] When the resin (X) contains other repeating units, the content thereof is preferably 30 mol % or less, more preferably 20 mol % or less, based on the total repeating units.

[0201] Resin (X) preferably contains a repeating unit represented by general formula (2) above in addition to the repeating unit represented by general formula (1), and more preferably contains a repeating unit represented by general formula (1-2) above and a repeating unit represented by general formula (2-2) above.

[0202] The weight-average molecular weight of resin (X) is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 20,000 or more. Furthermore, the weight-average molecular weight of resin (X) is preferably 200,000 or less, more preferably 150,000 or less, even more preferably 100,000 or less, and particularly preferably 85,000 or less. The weight-average molecular weight value is determined as a polystyrene equivalent value by GPC. The dispersity (molecular weight distribution) of resin (X) is usually 1.0 to 3.0, preferably 1.0 to 2.0, more preferably 1.0 to 1.8, and even more preferably 1.0 to 1.6. When the dispersity is within the above range, the resolution and resist shape tend to be more excellent.

[0203] Resin (X) can be synthesized by a conventional method (for example, radical polymerization), and details of the synthesis example will be shown in the Examples.

[0204] In the resist composition of the present invention, the content of resin (X) is preferably 50.0% by mass or more, more preferably 60.0% by mass or more, and even more preferably 70.0% by mass or more, based on the total solid content of the composition. The upper limit is 100% by mass or less, preferably 99.9% by mass or less. Resin (X) 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.

[0205] [Ionic Compound (A)] The resist composition of the present invention contains an ionic compound (A) (hereinafter also referred to as "compound (A)") that interacts with the interactive group in the resin (X) and has a non-decomposable organic cation that does not decompose when exposed to actinic rays or radiation.

[0206] The compound (A) is typically a compound having an ionic group capable of interacting with the interactive group in the resin (X). More specific examples include a compound having a cation having a cationic group as the ionic group and a counter anion, and a compound having an anion having an anionic group as the ionic group and a counter cation.

[0207] Compound (A) has a non-decomposable organic cation that does not decompose upon irradiation with actinic rays or radiation, i.e., compound (A) is not a compound that generates an acid upon irradiation with actinic rays or radiation, or X-rays, electron beams, or extreme ultraviolet rays.

[0208] The non-decomposable organic cation is not particularly limited as long as it is an organic cation that does not decompose when irradiated with actinic rays or radiation, and examples thereof include ammonium cation, pyridinium cation, imidazolium cation, phosphonium cation, carbocation, etc. From the viewpoint of interactivity, the ammonium cation, pyridinium cation, imidazolium cation, or phosphonium cation is preferred.

[0209] The ammonium cation is preferably a cation represented by the following general formula (A1).

[0210]

[0211] In general formula (A1), R ａ１ ~R ａ４ R each independently represents an alkyl group or an alkoxy group. ａ１ ~R ａ４ The alkyl group represented by R is preferably a linear or branched alkyl group having 1 to 8 carbon atoms, more preferably a methyl group, an ethyl group, or a butyl group, and even more preferably a methyl group. ａ１ ~R ａ４ The alkoxy group represented by is not particularly limited, but is preferably a straight or branched alkoxy group having 1 to 8 carbon atoms, such as a methoxy group.

[0212] R ａ１ ~R ａ４ may further have a substituent.

[0213] R ａ１ ~R ａ４ are preferably all alkyl groups having 1 to 4 carbon atoms, and more preferably all methyl groups.

[0214] The pyridinium cation is preferably a cation represented by the following general formula (A2).

[0215]

[0216] In general formula (A2), R ａ５ represents a hydrogen atom, an alkyl group, or an alkynyl group. ａ６ represents an alkyl group or an alkynyl group. p1 represents an integer of 0 to 5. When p1 represents an integer of 2 to 5, a plurality of R ａ６ may be the same or different.

[0217] R ａ５ and R ａ６ The alkyl group represented by is R ａ１ ~R ａ４ and R ａ５ and R ａ６ The alkynyl group represented by the formula (I) includes an alkynyl group having 2 to 6 carbon atoms.

[0218] R ａ５ and R ａ６ may further have a substituent.

[0219] R ａ５ is preferably an alkyl group having 1 to 8 carbon atoms, and more preferably a methyl group. ａ６ is preferably an alkyl group having 1 to 4 carbon atoms.

[0220] p1 represents an integer of 0 to 5, preferably an integer of 0 to 2, and more preferably 0.

[0221] The imidazolium cation is preferably a cation represented by the following general formula (A3).

[0222]

[0223] In general formula (A3), R ａ７ and R ａ８ R each independently represents a hydrogen atom, an alkyl group, or an alkoxy group. ａ９ represents an alkyl group or an alkoxy group. p2 represents an integer of 0 to 3. When p2 represents an integer of 2 or 3, a plurality of R ａ９ may be the same or different.

[0224] R ａ７ ~R ａ９ The alkyl group and alkoxy group represented by R in the above general formula (A1) are ａ１ ~R ａ４ The preferred examples are also the same.

[0225] R ａ７ ~R ａ９ may further have a substituent.

[0226] R ａ７ and R ａ８ is preferably an alkyl group having 1 to 8 carbon atoms, and more preferably a methyl group. ａ９ is preferably an alkyl group having 1 to 4 carbon atoms.

[0227] p2 represents an integer of 0 to 4, preferably an integer of 0 to 2, and more preferably 0.

[0228] The phosphonium cation is preferably a cation represented by the following general formula (A4).

[0229]

[0230] In general formula (A4), R ａ１０ ~R ａ１３ R each independently represents an alkyl group or an alkoxy group. ａ１０ ~R ａ１３ The alkyl group and alkoxy group represented by R in the above general formula (A1) are ａ１ ~R ａ４ Examples of the alkyl group and alkoxy group include those represented by the following formula:

[0231] R ａ１０ ~R ａ１３ may further have a substituent.

[0232] R ａ１０ ~R ａ１３ are preferably all alkyl groups having 1 to 8 carbon atoms, and more preferably all ethyl groups.

[0233] Examples of non-decomposable organic cations contained in compound (A) are listed below, but the present invention is not limited to these.

[0234]

[0235] The anion contained in the compound (A) is preferably an anion whose conjugate acid is HCl, HF, a carboxylic acid, an electron-withdrawing-group-substituted carboxylic acid, an electron-withdrawing-group-substituted phenolic hydroxyl group-containing compound, or a boric acid compound having an aryl group or a heteroaryl group, from the viewpoint of causing the compound (A) to strongly interact with the resin (X) when not exposed to light to form an association structure and reducing the solubility of the resin (X) in a developer, and more preferably an anion whose conjugate acid is HCl, HF, a carboxylic acid, or a boric acid compound having an aryl group or a heteroaryl group.

[0236] Examples of the carboxylate anion include an anion whose conjugate acid has a partial structure represented by the above formula (H-5-1) or formula (H-5-2), and for example, an anion represented by the following formula (B5) is preferred.

[0237]

[0238] In formula (B5), A ５ － represents an anionic group represented by the following formula (b-5-1) or formula (b-5-2): ａ１ represents a hydrogen atom or a monovalent organic group. ａ１ represents a single bond or a divalent linking group.

[0239] A ５ － represents an anionic group represented by the following formula (b-5-1) or formula (b-5-2):

[0240]

[0241] In formula (b-5-1), R Ｘ２ Each of the two R in formula (b-5-1) independently represents a hydrogen atom or a substituent other than an electron-withdrawing group. Ｘ２ may be the same or different. Ｘ３ represents a hydrogen atom or a substituent other than an electron-withdrawing group. Ｘ３ may be the same or different. * represents a bond.

[0242] R Ｘ２ Examples of the substituent other than the electron-withdrawing group represented by the formula (I) include an alkyl group not containing a fluorine atom (which may be linear or branched, and preferably has 1 to 15 carbon atoms) and a cycloalkyl group not containing a fluorine atom (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms).

[0243] R Ｘ３ Examples of the substituent other than the electron-withdrawing group represented by the formula (I) include an alkyl group not containing a fluorine atom (which may be linear or branched, and preferably has 1 to 15 carbon atoms), a cycloalkyl group not containing a fluorine atom (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms), a hydroxy group, and an alkoxy group (which may be linear or branched, and preferably has 1 to 15 carbon atoms).

[0244] In formula (B5), 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 The monovalent organic group is preferably an alkyl group, a cycloalkyl group, or an aryl group.

[0245] 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.

[0246] 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, an oxygen atom, and the like. 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. Examples of the substituent include, but are not limited to, a halogen atom.

[0247] L ａ１ The divalent linking group represented by is not particularly limited, but represents an alkylene group, a cycloalkylene group, an aromatic group, -O-, -CO-, -COO-, or a group 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, preferably an aromatic group having 6 to 20 carbon atoms, more preferably an aromatic group having 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, specifically, 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, 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. ａ１ Preferably, represents a single bond.

[0248] Examples of the electron-withdrawing group-substituted carboxylic acid anion include an anion whose conjugate acid has a partial structure represented by the above formula (H-4-1) or formula (H-4-2), and for example, an anion represented by the following formula (B4) is preferred.

[0249]

[0250] In formula (B4), A ４ －represents an anionic group represented by the following formula (b-4-1) or formula (b-4-2): ａ２ represents a hydrogen atom, a fluorine atom or a monovalent organic group. ａ２ represents a single bond or a divalent linking group.

[0251] A ４ － represents an anionic group represented by the following formula (b-4-1) or formula (b-4-2):

[0252]

[0253] In formula (b-4-1), R ＸＦ１ represents a hydrogen atom or a substituent, provided that two R ＸＦ１ At least one of the two R in formula (b-4-1) represents an electron-withdrawing group. ＸＦ１ may be the same or different. ＸＦ３ represents a hydrogen atom or a substituent. ＸＦ３ may be the same or different, provided that R ＸＦ３ At least one of the groups represents an electron-withdrawing group. * represents a bond.

[0254] R ＸＦ１ , R ＸＦ３ The substituent is not particularly limited, and examples thereof include an electron-withdrawing group, an alkyl group (which may be linear or branched, and preferably has 1 to 15 carbon atoms), an alkoxy 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), an aryl group (which may be monocyclic or polycyclic, and preferably has 6 to 20 carbon atoms), and a hydroxy group.

[0255] R ＸＦ１ When R is a perfluoroalkyl group, the number of carbon atoms in the perfluoroalkyl group is preferably 1 to 15, more preferably 1 to 10, and even more preferably 1 to 6. ＸＦ１ Preferably, all of the groups represent a fluorine atom or a perfluoroalkyl group, and more preferably, all of the groups represent a fluorine atom.

[0256] R ＸＦ３When R is a halogen atom, examples thereof include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and among these, a fluorine atom is preferred. ＸＦ３ When R is a perfluoroalkyl group, the number of carbon atoms in the perfluoroalkyl group is preferably 1 to 15, more preferably 1 to 10, and even more preferably 1 to 6. ＸＦ３ Preferably, all of the groups represent a fluorine atom or a perfluoroalkyl group, and more preferably, all of the groups represent a fluorine atom.

[0257] In formula (B4), R ａ２ is a monovalent organic group represented by R ａ１ Among them, a perfluoroalkyl group is preferred.

[0258] In formula (B4), L ａ２ is a divalent linking group represented by L in formula (B5). ａ１ and preferably represents a single bond.

[0259] Examples of the anion of the electron-withdrawing-group-substituted phenolic hydroxyl group-containing compound include an anion whose conjugate acid has a partial structure represented by formula (H-7) above, and for example, an anion represented by formula (B7) below is preferred.

[0260]

[0261] In formula (B7), A ７ － represents an anionic group represented by the following formula (b-7): ａ２ represents a hydrogen atom, a fluorine atom or a monovalent organic group. ａ２ represents a single bond or a divalent linking group.

[0262] A ７ － represents an anionic group represented by the following formula (b-7).

[0263]

[0264] In formula (b-7), R ＸＦ３ represents a hydrogen atom or a substituent. ＸＦ３ may be the same or different, provided that RＸＦ３ At least one of the groups represents an electron-withdrawing group. * represents a bond.

[0265] R ＸＦ３ is R in formula (b-4-2) ＸＦ３ The same applies to preferred examples. ａ２ , L ａ２ is R in formula (B4). ａ２ , L ａ２ The same applies to preferred examples.

[0266] The anion of the boric acid compound having an aryl group or a heteroaryl group is preferably, for example, an anion represented by the following formula (B10).

[0267]

[0268] In formula (B10), R ｂ１ ~R ｂ４ each independently represents a substituent. ｂ１ ~R ｂ４ At least one of represents an aryl group or a heteroaryl group.

[0269] R ｂ１ ~R ｂ４ The substituent represented by the formula (I) is not particularly limited, and examples thereof include an aryl group, a heteroaryl group, a halogen atom (preferably a fluorine atom), and a cyano group.

[0270] R ｂ１ ~R ｂ４The aryl group and the heteroaryl group represented by at least one of the above 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, a pyridine ring, an imidazolyl ring, an indole ring, a benzofuran ring, a benzothiazole ring, and a benzothiophene ring.

[0271] The aryl group and heteroaryl group may further have a substituent. The substituent is not particularly limited, and examples thereof include the groups exemplified as the substituent T above.

[0272] In addition, R ｂ１ ~R ｂ４ 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.

[0273] R ｂ１ ~R ｂ４ The substituents represented by R may all be the same or different. ｂ１ ~R ｂ４ When the substituents represented by R ｂ１ ~R ｂ３ The substituents represented by R ｂ４ is a substituent represented by R ｂ１ ~R ｂ３ or an embodiment in which the substituent is different from the substituent represented by R ｂ１ ~R ｂ２ The substituents represented by Rｂ３ ~R ｂ４ is a substituent represented by R ｂ１ ~R ｂ２ It is also preferable that the substituent is different from the substituent represented by the following formula:

[0274] Also, R ｂ１ ~R ｂ４ When the substituents represented by R ｂ１ ~R ｂ３ and R ｂ４ is a substituent represented by R ｂ１ ~R ｂ３ and is a heteroaryl group which may have a substituent (preferably a heteroaryl group containing a nitrogen atom which may have a substituent), which is different from the substituent represented by R ｂ１ ~R ｂ３ and R ｂ４ is a substituent represented by R ｂ１ ~R ｂ３ and is an aryl group having an unsubstituted or substituted amino group as a substituent.

[0275] Also, R ｂ１ ~R ｂ４ When the substituents represented by R ｂ１ ~R ｂ２ and R ｂ３ ~R ｂ４ is a substituent represented by R ｂ１ ~R ｂ２ and is a heteroaryl group which may have a substituent (preferably a heteroaryl group containing a nitrogen atom which may have a substituent).

[0276] R ｂ１ ~R ｂ４ are preferably all aryl groups, and more preferably all phenyl groups.

[0277] Examples of the anion possessed by compound (A) are given below, but the present invention is not limited to these.

[0278]

[0279] In the resist composition of the present invention, the content of the ionic compound (A) is preferably 0.1 to 20% by mass, based on the total solids content of the resist composition. If the content is 0.1% by mass or more, the dissolution contrast between the unexposed and exposed areas, which occurs depending on whether or not an association structure with the resin (X) is formed, is enhanced, making it easier to achieve the effects of the present invention. The lower limit of the content is more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and particularly preferably 2.0% by mass or more. Furthermore, if the content is 20% by mass or less, the unexposed areas have appropriate solubility, resulting in better sensitivity, making it easier to achieve the effects of the present invention. The upper limit of the content is more preferably 10.0% by mass or less, even more preferably 5.0% by mass or less. The ionic compound (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 be within the above-mentioned preferred content range.

[0280] [Onium Salt Compound (B)] The resist composition of the present invention contains an onium salt compound (B) that generates an acid upon irradiation with actinic rays or radiation. That is, the onium salt compound (B) is a photodecomposable onium salt compound. The conjugate acid of the anion of the ionic compound (A) and the conjugate acid of the onium salt compound (B) have different acidities. The conjugate acid of the anion of the ionic compound (A) and the conjugate acid of the onium salt compound (B) have different acid strengths. The conjugate acid of the anion of the onium salt compound (B) may be a stronger acid than the conjugate acid of the anion of the ionic compound (A), or the conjugate acid of the anion of the onium salt compound (B) may be a weaker acid than the conjugate acid of the anion of the ionic compound (A).

[0281] An example of a preferred embodiment of the onium salt compound (B) is "M Ｂ ＋ X Ｂ －", which generates an inorganic acid or an organic acid when irradiated with actinic rays or radiation. Ｂ ＋ X Ｂ － In the compound represented by the formula ", M Ｂ ＋ represents an organic cation, and X Ｂ － represents an inorganic anion or an organic anion.

[0282] M Ｂ ＋ Examples of the organic cation represented by formula (ZaI) include a sulfonium cation, an iodonium cation, and a pyridinium cation, and the sulfonium cation or the iodonium cation is preferred. Among these, the organic cation represented by formula (ZaI) (cation (ZaI)) or the organic cation represented by formula (ZaII) (cation (ZaII)) is preferred.

[0283]

[0284] In the above formula (ZaI), R ２０１ , R ２０２ , and R ２０３ R each independently represents an organic group. ２０１ , R ２０２ , and R ２０３ The number of carbon atoms in the organic group represented by R is usually 1 to 30, and preferably 1 to 20. ２０１ ~R ２０３ Two of these 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 groups formed by combining two of these include alkylene groups (e.g., butylene and pentylene groups) and —CH ２ -CH ２ -O-CH ２ -CH ２ - are listed.

[0285] Suitable embodiments of the organic cation in formula (ZaI) include cation (ZaI-1), cation (ZaI-2), an organic cation represented by formula (ZaI-3b) (cation (ZaI-3b)), and an organic cation represented by formula (ZaI-4b) (cation (ZaI-4b)), which will be described later.

[0286] First, the cation (ZaI-1) will be described. The cation (ZaI-1) is R in the above formula (ZaI). ２０１ ~R ２０３ is an arylsulfonium cation, in which at least one of R is an aryl group. ２０１ ~R ２０３ may all be aryl groups, or R ２０１ ~R ２０３ A part of R may be an aryl group, and the rest may be an alkyl group or a cycloalkyl group. ２０１ ~R ２０３ is an aryl group, and R ２０１ ~R ２０３ The remaining two of R 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 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 Examples of the arylsulfonium cation include triarylsulfonium cation, diarylalkylsulfonium cation, aryldialkylsulfonium cation, diarylcycloalkylsulfonium cation, and aryldicycloalkylsulfonium cation.

[0287] The aryl group contained in the arylsulfonium cation is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure containing an oxygen atom, a nitrogen atom, or a sulfur atom. Examples of heterocyclic structures include pyrrole residues, furan residues, thiophene residues, indole residues, benzofuran residues, and benzothiophene residues. When the arylsulfonium cation has two or more aryl groups, the two or more aryl groups may be the same or different. The alkyl group or cycloalkyl group optionally contained in the arylsulfonium cation is preferably a linear alkyl group having 1 to 15 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, or a cycloalkyl group having 3 to 15 carbon atoms, and more preferably, for example, a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, or a cyclohexyl group.

[0288] R ２０１ ~R ２０３ Preferred substituents that the aryl group, alkyl group, and cycloalkyl group may have are each independently an alkyl group (e.g., having 1 to 15 carbon atoms), a cycloalkyl group (e.g., having 3 to 15 carbon atoms), an aryl group (e.g., having 6 to 14 carbon atoms), an alkoxy group (e.g., having 1 to 15 carbon atoms), a cycloalkylalkoxy group (e.g., having 1 to 15 carbon atoms), a halogen atom (e.g., fluorine, iodine), a hydroxyl group, a carboxyl group, an ester group, a sulfinyl group, a sulfonyl group, an alkylthio group, and a phenylthio group. The above substituents may further have a substituent if possible; for example, it is also preferred that the above alkyl group has a halogen atom as a substituent to form a halogenated alkyl group such as a trifluoromethyl group.

[0289] Next, the cation (ZaI-2) will be described. The cation (ZaI-2) is a cation represented by the formula (ZaI) R ２０１ ~R ２０３ are each independently a cation representing an organic group that does not have an aromatic ring. Here, the aromatic ring also includes an aromatic ring containing a heteroatom. ２０１ ~R ２０３The organic group having no aromatic ring as R generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. ２０１ ~R ２０３ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or an alkoxycarbonylmethyl group, and still more preferably a linear or branched 2-oxoalkyl group.

[0290] R ２０１ ~R ２０３ Examples of the alkyl and cycloalkyl groups include linear alkyl groups having 1 to 10 carbon atoms or branched alkyl groups having 3 to 10 carbon atoms (e.g., methyl, ethyl, propyl, butyl, and pentyl groups), and cycloalkyl groups having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, and norbornyl groups). ２０１ ~R ２０３ may be further substituted with a halogen atom, an alkoxy group (eg, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

[0291] Next, the cation (ZaI-3b) will be described. The cation (ZaI-3b) is a cation represented by the following formula (ZaI-3b).

[0292]

[0293] In formula (ZaI-3b), R １ｃ ~R ５ｃ R each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitro group, an alkylthio group, or an arylthio group. ６ｃ and R ７ｃ R each independently represents a hydrogen atom, an alkyl group (such as a t-butyl group), a cycloalkyl group, a halogen atom, a cyano group, or an aryl group. ｘ and R ｙeach independently represents an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group, or a vinyl group.

[0294] 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 each of these rings may independently contain an oxygen atom, a sulfur atom, a ketone group, an ester bond, or an amide bond. Examples of the ring include aromatic or non-aromatic hydrocarbon rings, aromatic or non-aromatic heterocycles, and polycyclic fused rings formed by combining two or more of these rings. Examples of the ring include 3- to 10-membered rings, preferably 4- to 8-membered rings, and more preferably 5- or 6-membered rings.

[0295] 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. A 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.

[0296] R １ｃ ~R ５ｃ , R ６ｃ , R ７ｃ , R ｘ , R ｙ , and R １ｃ ~R ５ｃ Two or more of the following, R ５ｃ and R ６ｃ , R ６ｃand R ７ｃ , R ５ｃ and R ｘ , and R ｘ and R ｙ The ring formed by bonding together may have a substituent.

[0297] Next, the cation (ZaI-4b) will be described. The cation (ZaI-4b) is a cation represented by the following formula (ZaI-4b).

[0298]

[0299] In formula (ZaI-4b), l represents an integer of 0 to 2. r represents an integer of 0 to 8. １３ represents a hydrogen atom, a halogen atom (e.g., a fluorine atom, an iodine atom, etc.), a hydroxyl group, an alkyl group, a halogenated alkyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, or a group having a cycloalkyl group (which may be a cycloalkyl group itself or a group containing a cycloalkyl group as a part). These groups may have a substituent. R １４ represents a hydroxyl group, a halogen atom (e.g., a fluorine atom, an iodine atom, etc.), an alkyl group, a halogenated alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group, or a group having a cycloalkyl group (which may be a cycloalkyl group itself or a group containing a cycloalkyl group as a part). These groups may have a substituent. R １４ When a plurality of R are present, each independently represents the above group such as a hydroxyl group. １５ each independently represents an alkyl group, a cycloalkyl group, or a naphthyl group. 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 bonded to each other to form a ring structure. １５The ring formed by bonding together may have a substituent.

[0300] In formula (ZaI-4b), R １３ , R １４ , and R １５ The alkyl group is preferably linear or branched, and the number of carbon atoms in the alkyl group is preferably 1 to 10. The alkyl group is more preferably a methyl group, an ethyl group, an n-butyl group, a t-butyl group, or the like.

[0301] Next, formula (ZaII) will be described. In formula (ZaII), R ２０４ and R ２０５ R each independently represents an aryl group, an alkyl group, or a cycloalkyl group. ２０４ and R ２０５ The aryl group in R is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. ２０４ and R ２０５ The aryl group in R may be an aryl group having a heterocycle containing an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Examples of the skeleton of the aryl group having a heterocycle include pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene. ２０４ and R ２０５ The alkyl group and cycloalkyl group are preferably a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (e.g., methyl, ethyl, propyl, butyl, or pentyl), or a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, or norbornyl).

[0302] R ２０４ and R ２０５ The aryl group, alkyl group, and cycloalkyl group in R may each independently have a substituent. ２０４ and R ２０５Examples of the substituent that the aryl group, alkyl group, and cycloalkyl group may have include an alkyl group (e.g., having 1 to 15 carbon atoms), a cycloalkyl group (e.g., having 3 to 15 carbon atoms), an aryl 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.

[0303] The pyridinium cation is preferably a cation represented by the following general formula (A5).

[0304]

[0305] In general formula (A5), R ａ１４ represents an alkoxy group. ａ１５ represents an alkyl group or an aryl group. p3 represents an integer of 0 to 5. When p3 represents an integer of 2 to 5, a plurality of R ａ１５ may be the same or different.

[0306] R ａ１４ The alkyl group in the alkoxy group represented by is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0307] R ａ１５ The alkyl group represented by R is preferably a linear or branched alkyl group having 1 to 8 carbon atoms, more preferably a methyl group, an ethyl group, or a butyl group, and even more preferably a methyl group. ａ１５ The aryl group represented by is preferably an aryl group having 6 to 15 carbon atoms, more preferably a phenyl group.

[0308] R ａ１４ and R ａ１５ may further have a substituent.

[0309] p3 represents an integer of 0 to 5, preferably an integer of 0 to 2.

[0310] M Ｂ ＋ The organic cations represented by the following formulae are exemplified, but the present invention is not limited thereto.

[0311]

[0312] X Ｂ － represents an inorganic anion or an organic anion. The acid generated from the onium salt compound (B) upon irradiation with actinic rays or radiation, i.e., the anion (X Ｂ － The conjugate acid of the ionic compound (A) is preferably an acid stronger than the conjugate acid of the anion of the ionic compound (A). Examples of the conjugate acid include inorganic super acids, HI, HBr, electron-withdrawing group-substituted sulfonimides, electron-withdrawing group-substituted sulfonic acids, tetrafluoroboric acid, HCl, and sulfonic acids. The conjugate acid is preferably an inorganic acid or organic acid stronger than tetrafluoroboric acid, and more preferably an inorganic super acid, HI, HBr, electron-withdrawing group-substituted sulfonimides, or electron-withdrawing group-substituted sulfonic acids.

[0313] The inorganic superacid anion is hexafluorophosphate anion (PF ６ － ), fluoroantimonate anion (SbF ６ － ), perchlorate anion (ClO ４ － ) and the like, with hexafluorophosphate anion and fluoroantimonate anion being preferred.

[0314] Examples of the electron-withdrawing group-substituted sulfonimide anion include an anion whose conjugate acid has a partial structure represented by the above formula (H-1), and for example, an anion represented by the following formula (B1) is preferred:

[0315]

[0316] In formula (B1), A １ － represents an anionic group represented by the following formula (b-1): ａ２ represents a hydrogen atom, a fluorine atom or a monovalent organic group. ａ２ represents a single bond or a divalent linking group.

[0317] A １ － represents an anionic group represented by the following formula (b-1).

[0318]

[0319] In formula (b-1), R ＸＦ２ represents an electron-withdrawing group. * represents a bond.

[0320] R ＸＦ２ When is a perfluoroalkyl group, the perfluoroalkyl group preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms.

[0321] In formula (B1), R ａ２ , L ａ２ is R in formula (B4). ａ２ , L ａ２ The same applies to preferred examples. １ － and R ａ２ may be bonded to each other to form a ring.

[0322] The electron-withdrawing group-substituted sulfonimide anion is preferably an anion whose conjugate acid is a fluorinated alkylsulfonimide, and R ＸＦ２ is preferably an anion representing a perfluoroalkyl group.

[0323] Examples of the electron-withdrawing group-substituted sulfonate anion include an anion whose conjugate acid has a partial structure represented by the above formula (H-2-1) or formula (H-2-2), and for example, an anion represented by the following formula (B2) is preferred:

[0324]

[0325] In formula (B2), A ２ － represents an anionic group represented by the following formula (b-2-1) or formula (b-2-2): ａ２ represents a hydrogen atom, a fluorine atom or a monovalent organic group. ａ２ represents a single bond or a divalent linking group.

[0326] A ２ － represents an anionic group represented by the following formula (b-2-1) or formula (b-2-2).

[0327]

[0328] In formula (b-2-1), R ＸＦ１ represents a hydrogen atom or a substituent, provided that two R ＸＦ１ At least one of the two R in formula (b-2-1) represents an electron-withdrawing group. ＸＦ１ may be the same or different. ＸＦ３ represents a hydrogen atom or a substituent. ＸＦ３ may be the same or different, provided that R ＸＦ３ At least one of the groups represents an electron-withdrawing group. * represents a bond.

[0329] R ＸＦ１ is R in formula (b-4-1) ＸＦ１ The same applies to preferred examples. ＸＦ３ is R in formula (b-4-2) ＸＦ３ The same applies to preferred examples. ａ２ and L ａ２ respectively represent R in formula (B4). ａ２ and L ａ２ The same applies to preferred examples.

[0330] The electron-withdrawing group-substituted sulfonate anion is preferably an anion whose conjugate acid is a fluorinated alkylsulfonic acid. ２ － is preferably an anionic group represented by the above formula (b-2-1).

[0331] Examples of sulfonate anions include anions whose conjugate acid has a partial structure represented by the above formula (H-3-1) or formula (H-3-2), and for example, an anion represented by the following formula (B3) is preferred.

[0332]

[0333] In formula (B3), A ３ － represents an anionic group represented by the following formula (b-3-1) or formula (b-3-2): ａ１ represents a hydrogen atom or a monovalent organic group. ａ１ represents a single bond or a divalent linking group.

[0334] A ３ － represents an anionic group represented by the following formula (b-3-1) or formula (b-3-2):

[0335]

[0336] In formula (b-3-1), R Ｘ２ Each of the two R in formula (b-3-1) independently represents a hydrogen atom or a substituent other than an electron-withdrawing group. Ｘ２ may be the same or different. Ｘ３ represents a hydrogen atom or a substituent other than an electron-withdrawing group. Ｘ３ may be the same or different. * represents a bond.

[0337] R Ｘ２ is R in formula (b-5-1) Ｘ２ The same applies to preferred examples. Ｘ３ is R in formula (b-5-2) Ｘ３ The same applies to preferred examples. ａ１ and L ａ１ are R in formula (B5), respectively. ａ１ and L ａ１ The same applies to preferred examples.

[0338] In a preferred embodiment, the acid generated from the onium salt compound (B) upon irradiation with actinic rays or radiation, i.e., the anion (X Ｂ － The conjugate acid of the anion (X) of the ionic compound (A) is preferably weaker than the conjugate acid of the anion of the ionic compound (A). For example, Ｂ － Preferably, the conjugate acid of is HCl.

[0339] The anion (X Ｂ － The conjugate acid of (I) is particularly preferably hexafluorophosphoric acid, fluoroantimonic acid, fluorinated alkylsulfonimide, or fluorinated alkylsulfonic acid.

[0340] X Ｂ － The anions represented by the formula (I) are exemplified below, but the present invention is not limited thereto.

[0341]

[0342] The organic acid generated from the onium salt compound (B) by the action of exposure to light may be a polyacid having two or more acid groups.

[0343] As the onium salt compound (B), 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.

[0344] In the resist composition of the present invention, the content of the onium salt compound (B) is preferably 0.1 to 20% by mass, based on the total solids content of the resist composition. If the content is 0.1% by mass or more, the acid generated by exposure acts on the ionic compound (A) and dissolves the association structure between the ionic compound (A) and the resin (X), thereby increasing the dissolution contrast between the unexposed and exposed areas, making it easier to achieve the effects of the present invention. The lower limit of the content is more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and particularly preferably 2.0% by mass or more. Furthermore, if the content is 20% by mass or less, the unexposed areas will have appropriate solubility, resulting in better sensitivity and making it easier to achieve the effects of the present invention. The upper limit of the content is more preferably 10.0% by mass or less, even more preferably 5.0% by mass or less. The onium salt compound (B) 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 be within the above-mentioned preferred content range.

[0345] [Onium Salt Compound (C)] The resist composition of the present invention may further contain an onium salt compound (C) that generates an acid weaker than the conjugate acid of the anion of the onium salt compound (B) upon irradiation with actinic rays or radiation. That is, the onium salt compound (C) is also a photodegradable onium salt compound. The onium salt compound (C) traps the acid generated from the onium salt compound (B) or the like upon exposure, and acts as a quencher that suppresses the dissolution of the association structure between the resin (X) and the ionic compound (A) in the unexposed areas due to the excess acid generated. Furthermore, from the viewpoint of the ability to dissolve the association structure between the resin (X) and the ionic compound (A) in the exposed areas, the onium salt compound (C) is preferably an onium salt compound that generates an acid stronger than the conjugate acid of the anion of the ionic compound (A) but weaker than the conjugate acid of the anion of the onium salt compound (B).

[0346] An example of a preferred embodiment of the onium salt compound (C) is "M Ｃ ＋ X Ｃ － ", which generates an inorganic acid or an organic acid when irradiated with actinic rays or radiation. Ｃ ＋ X Ｃ － In the compound represented by the formula ", M Ｃ ＋ represents an organic cation, and X Ｃ － represents an inorganic anion or an organic anion.

[0347] M Ｃ ＋ Examples of the organic cation represented by formula (ZaI) include a sulfonium cation, an iodonium cation, a pyridinium cation, etc., and the sulfonium cation or the iodonium cation is preferred. Among these, the organic cation represented by formula (ZaI) (cation (ZaI)) or the organic cation represented by formula (ZaII) (cation (ZaII)) is preferred.

[0348] X Ｃ －represents an inorganic anion or an organic anion. The acid generated from the onium salt compound (C) by the action of exposure, i.e., the anion (X Ｃ － The conjugate acid of is preferably tetrafluoroboric acid or an inorganic acid or organic acid weaker than tetrafluoroboric acid, more preferably tetrafluoroboric acid, HCl, sulfonic acid, an electron-withdrawing group-substituted carboxylic acid, HF, carboxylic acid, a boric acid compound having an aryl group or a heteroaryl group, an electron-withdrawing group-substituted sulfonamide, an electron-withdrawing group-substituted phenolic hydroxyl group-containing compound, sulfonamide, or a phenolic hydroxyl group-containing compound. Among these, a boric acid compound having an aryl group or a heteroaryl group, or a sulfonic acid is more preferred, and a boric acid compound having an aryl group or a heteroaryl group is particularly preferred.

[0349] Examples of sulfonate anions include anions whose conjugate acid has a partial structure represented by the above formula (H-3-1) or formula (H-3-2), and for example, an anion represented by the above formula (B3) is preferred.

[0350] Examples of the electron-withdrawing group-substituted carboxylate anion include an anion whose conjugate acid has a partial structure represented by the above formula (H-4-1) or formula (H-4-2), and for example, an anion represented by the above formula (B4) is preferred.

[0351] Examples of the carboxylate anion include an anion whose conjugate acid has a partial structure represented by the above formula (H-5-1) or formula (H-5-2), and for example, an anion represented by the above formula (B5) is preferred.

[0352] The anion of the boric acid compound having an aryl group or a heteroaryl group is preferably an anion represented by the above formula (B10).

[0353] Examples of the electron-withdrawing group-substituted sulfonamide anion include an anion whose conjugate acid has a partial structure represented by the above formula (H-6-1) or formula (H-6-2), and for example, an anion represented by the following formula (B6) is preferred.

[0354]

[0355] In formula (B6), A ６ － represents an anionic group represented by the following formula (b-6-1) or formula (b-6-2): ａ２ represents a hydrogen atom or a monovalent organic group. ａ２ represents a single bond or a divalent linking group.

[0356] A ６ － represents an anionic group represented by the following formula (b-6-1) or formula (b-6-2).

[0357]

[0358] In formula (b-6-1) and formula (b-6-2), R ＸＦ２ each independently represents an electron-withdrawing group. * represents a bond.

[0359] R ＸＦ２ represents R in formula (b-1). ＸＦ２ The same applies to preferred examples. ａ２ , L ａ２ is R in formula (B4). ａ２ , L ａ２ The same applies to preferred examples. ６ － and R ａ２ may be bonded to each other to form a ring.

[0360] Examples of the anion of the electron-withdrawing-group-substituted phenolic hydroxyl group-containing compound include an anion whose conjugate acid has a partial structure represented by the above formula (H-7), and for example, an anion represented by the above formula (B7) is preferred.

[0361] Examples of sulfonamide anions include anions whose conjugate acid has a partial structure represented by the above formula (H-8-1) or formula (H-8-2), and for example, an anion represented by the following formula (B8) is preferred.

[0362]

[0363] In formula (B8), A ８－ represents an anionic group represented by the following formula (b-8-1) or formula (b-8-2): ａ１ represents a hydrogen atom or a monovalent organic group. ａ１ represents a single bond or a divalent linking group.

[0364] A ８ － represents an anionic group represented by the following formula (b-8-1) or formula (b-8-2):

[0365]

[0366] In formula (b-8-1) and formula (b-8-2), R Ｘ１ each independently represents a substituent other than an electron-withdrawing group. * represents a bond.

[0367] R Ｘ１ The substituent other than the electron-withdrawing group is not particularly limited, and examples thereof include an alkyl group not containing a fluorine atom (which may be linear or branched, and preferably has 1 to 15 carbon atoms) and a cycloalkyl group not containing a fluorine atom (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms).

[0368] R ａ１ and L ａ１ are R in formula (B5), respectively. ａ１ and L ａ１ The same applies to preferred examples. ８ － and R ａ１ may be bonded to each other to form a ring.

[0369] Examples of the anion of the phenolic hydroxyl group-containing compound include an anion whose conjugate acid has a partial structure represented by formula (H-9) above, and for example, an anion represented by formula (B9) below is preferred.

[0370]

[0371] In formula (B9), A ９ － represents an anionic group represented by the following formula (b-9): ａ１ represents a hydrogen atom or a monovalent organic group. ａ１represents a single bond or a divalent linking group.

[0372] A ９ － represents an anionic group represented by the following formula (b-9).

[0373]

[0374] In formula (b-9), R Ｘ３ represents a hydrogen atom or a substituent other than an electron-withdrawing group. Ｘ３ may be the same or different. * represents a bond.

[0375] R Ｘ３ is R in formula (b-5-1) Ｘ２ The same applies to preferred examples. ａ１ and L ａ１ are R in formula (B5), respectively. ａ１ and L ａ１ The same applies to preferred examples.

[0376] X Ｃ － The anions represented by the formula (I) are exemplified below, but the present invention is not limited thereto.

[0377]

[0378]

[0379] The organic acid generated from the onium salt compound (C) by the action of exposure to light may be a polyacid having two or more acid groups.

[0380] In the resist composition of the present invention, the content of the onium salt compound (C) is preferably 0.1 to 20% by mass, based on the total solids content of the resist composition. A content of 0.1% by mass or more is effective in trapping acid generated from the onium salt compound (B) and the like, and in suppressing dissolution of the association structure between the resin (X) and the ionic compound (A) in the unexposed areas due to excess acid generated. The lower limit of the content is more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and particularly preferably 2.0% by mass or more. Furthermore, a content of 20% by mass or less ensures appropriate solubility in the unexposed areas, resulting in superior sensitivity, and also making it easier to achieve the effects of the present invention. The upper limit of the content is more preferably 10.0% by mass or less, even more preferably 5.0% by mass or less. The onium salt compound (C) 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 be within the above-mentioned preferred content range.

[0381] [Solvent] The resist composition of the present invention 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, and alkylene carbonate. Note that this solvent may further contain components other than components (M1) and (M2).

[0382] When such a solvent is used in combination with resin (X), the coatability of the resist composition is improved and a pattern with fewer development defects is easily formed. This is presumably because these solvents have an excellent balance of solubility, boiling point, and viscosity for resin (X), and therefore can suppress unevenness in the film thickness of the resist film, which is a composition film of the resist composition, and the occurrence of precipitates during spin coating.

[0383] As the component (M1), at least one selected from the group consisting of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether propionate, and propylene glycol monoethyl ether acetate is preferred, and propylene glycol monomethyl ether acetate (PGMEA) is more preferred.

[0384] The following are preferred as component (M2). As the propylene glycol monoalkyl ether, propylene glycol monomethyl ether (PGME) and propylene glycol monoethyl ether (PGEE) are preferred. As the lactate ester, ethyl lactate, butyl lactate, or propyl lactate is preferred. As the acetate ester, methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, isoamyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, or 3-methoxybutyl acetate is preferred. Butyl butyrate is also preferred. The alkoxypropionic acid ester is preferably methyl 3-methoxypropionate (MMP) or ethyl 3-ethoxypropionate (EEP). The chain ketone is preferably 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 2-heptanone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, or methyl amyl ketone. The cyclic ketone is preferably methylcyclohexanone, isophorone, cyclopentanone, or cyclohexanone. The lactone is preferably γ-butyrolactone, and the alkylene carbonate is preferably propylene carbonate.

[0385] As the component (M2), propylene glycol monomethyl ether (PGME), ethyl lactate, ethyl 3-ethoxypropionate, methyl amyl ketone, cyclohexanone, butyl acetate, pentyl acetate, γ-butyrolactone, or propylene carbonate is more preferred.

[0386] In addition to the above-mentioned components, the solvent preferably contains an ester-based solvent having 7 or more carbon atoms (preferably 7 to 14, more preferably 7 to 12, and even more preferably 7 to 10) and 2 or less heteroatoms. Preferred ester-based solvents having 7 or more carbon atoms and 2 or less heteroatoms include amyl acetate, 2-methylbutyl acetate, 1-methylbutyl acetate, hexyl acetate, pentyl propionate, hexyl propionate, butyl propionate, isobutyl isobutyrate, heptyl propionate, and butyl butanoate, and isoamyl acetate is more preferred.

[0387] Component (M2) preferably has a flash point (hereinafter also referred to as fp) of 37°C or higher. Examples of such component (M2) include propylene glycol monomethyl ether (fp: 47°C), ethyl lactate (fp: 53°C), ethyl 3-ethoxypropionate (fp: 49°C), methyl amyl ketone (fp: 42°C), cyclohexanone (fp: 44°C), pentyl acetate (fp: 45°C), methyl 2-hydroxyisobutyrate (fp: 45°C), γ-butyrolactone (fp: 101°C), and propylene carbonate (fp: 132°C). Among these, propylene glycol monoethyl ether, ethyl lactate, pentyl acetate, and cyclohexanone are more preferred, and propylene glycol monoethyl ether and ethyl lactate are even more preferred. The term "flash point" used herein refers to the value listed in the reagent catalogs of Tokyo Chemical Industry Co., Ltd. or Sigma-Aldrich Corporation.

[0388] The solvent preferably contains component (M1). It is more preferable that the solvent consists essentially of component (M1) alone, or is a mixed solvent of component (M1) with other components. In the latter case, it is even more preferable that the solvent contains both component (M1) and component (M2). The mass ratio (M1 / M2) of component (M1) to component (M2) is preferably within the range of 100 / 0 to 15 / 85, more preferably within the range of 100 / 0 to 40 / 60, and even more preferably within the range of 100 / 0 to 60 / 40. In other words, it is preferable that the solvent consists solely of component (M1) or contains both component (M1) and component (M2), and that the mass ratio between them is as follows: That is, in the latter case, the mass ratio of component (M1) to component (M2) is preferably 15 / 85 or more, more preferably 40 / 60 or more, and even more preferably 60 / 40 or more. By adopting such a configuration, it is possible to further reduce the number of development defects.

[0389] When the solvent contains both the component (M1) and the component (M2), the mass ratio of the component (M1) to the component (M2) is, for example, 99 / 1 or less.

[0390] 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.

[0391] The content of the solvent in the resist composition of the present invention is preferably determined so that the solids concentration is 0.5 to 30 mass %, and more preferably 1 to 20 mass %, in order to achieve better coatability.

[0392] [Surfactant] The resist composition of the present invention may contain a surfactant. When a surfactant is contained, a pattern with better adhesion and fewer development defects can be formed. 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.

[0393] These surfactants may be used alone or in combination of two or more.

[0394] When the resist composition of the present invention contains a surfactant, the content of the surfactant is preferably from 0.0001 to 2 mass %, and more preferably from 0.0005 to 1 mass %, based on the total solid content of the composition.

[0395] [Resist Film and Pattern Forming Method] The present invention also relates to a resist film formed from the above-mentioned actinic ray-sensitive or radiation-sensitive resin composition. The present invention also relates to a pattern forming method comprising the steps of forming a resist film on a substrate using the above-mentioned actinic ray-sensitive or radiation-sensitive resin composition, exposing the resist film to light, and developing the exposed resist film using a developer.

[0396] The procedure for the pattern formation method using the resist composition is not particularly limited, but preferably includes the following steps: Step 1: Forming a resist film on a substrate using the resist composition, Step 2: Exposing the resist film to light, and Step 3: Developing the exposed resist film using a developer. The procedure for each of the above steps will now be described in detail.

[0397] <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.

[0398] 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.

[0399] 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.

[0400] 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.

[0401] 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 and EB exposure are used, the thickness of the resist film is more preferably 10 to 65 nm, and even more preferably 15 to 50 nm. Furthermore, 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.

[0402] 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 2013-061648 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.

[0403] <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 far ultraviolet light with a wavelength of 250 nm or less, more preferably 220 nm or less, and particularly preferably 1 to 200 nm, specifically KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ２ These include excimer laser (157 nm), EUV (13 nm), X-ray, and electron beam.

[0404] After exposure, it is preferable to perform post-exposure heat treatment (also referred to as post-exposure baking) before development. Post-exposure heat treatment promotes the reaction of the exposed area, 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.

[0405] <Step 3: Development Step> Step 3 is a step of developing the exposed resist film using a developer to form a pattern. The developer is preferably a developer containing an organic solvent (hereinafter also referred to as an organic developer).

[0406] 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 then left stationary 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). 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.

[0407] 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.

[0408] 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.

[0409] <Other Steps> The pattern formation method preferably includes, after step 3, a step of cleaning with a rinse liquid.

[0410] The rinse liquid used in the rinse step after the development step using an organic developer is not particularly limited as long as it does not dissolve the pattern, and a solution containing a general organic solvent can be used. The rinse liquid is preferably a rinse liquid containing at least one organic solvent selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents.

[0411] 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 surface of the substrate (spray method). The pattern formation method of the present invention 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).

[0412] 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.

[0413] The resist composition and various materials used in the pattern formation method of the present invention (e.g., solvent, developer, rinse, anti-reflective coating composition, top coat 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. 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.

[0414] 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.

[0415] 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).

[0416] 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.

[0417] The resist composition may also contain water as an impurity. When water is contained as an impurity, the lower the content of water, the more preferable, but the resist composition may contain 1 to 30,000 ppm by mass of water relative to the entire resist composition. The resist composition may also contain residual monomers as impurities (for example, monomers derived from the raw material monomers used in the synthesis of resin (X)). When residual monomers are contained as impurities, the lower the content of residual monomers, the more preferable, but the resist composition may contain 1 to 30,000 ppm by mass of water relative to the entire solid content of the resist composition.

[0418] 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, and more preferably 5% by mass or less. 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, polyethylene, polypropylene, or fluororesin (such as polytetrafluoroethylene or perfluoroalkoxy resin) that have been antistatically treated can be used.

[0419] [Method for Manufacturing Electronic Device] The present invention 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. The electronic device of the present invention is suitable for installation in electrical and electronic equipment (such as home appliances, office automation (OA), media-related equipment, optical equipment, and communication equipment).

[0420] 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.

[0421] [Various Components of Actinic Ray-Sensitive or Radiation-Sensitive Resin Composition] [Resin (X)] The resins (X-1 to X-8 and RX-1 to RX-2) shown in Table 2 are shown below. Resin X-5 was synthesized by the synthesis method (Synthesis Example 1) described below. Resins X-1 to 4, X-6 to X-8, and RX-1 to RX-2 were synthesized according to Synthesis Example 1 or by known methods. Resins RX-1 to RX-2 correspond to comparative resins. Table 1 shows the compositions of resins X-1 to X-8 and RX-1 to RX-2 (types of raw material monomers, composition ratios (mol %) of repeating units, weight average molecular weights (Mw), and dispersities (Mw / Mn)). The weight average molecular weight (Mw) and dispersity (Mw / Mn) of Resins X-1 to X-8 and RX-1 to RX-2 were measured by GPC (carrier: tetrahydrofuran (THF)) (in terms of polystyrene). The composition ratios (mol % ratios) of the resins were as follows: １３ Measurement was performed by C-NMR (Nuclear Magnetic Resonance).

[0422]

[0423] In the resins X-1 to X-8 and RX-1 to RX-2 in Table 1, the raw material monomers are as follows. The raw material monomer for repeating unit 1 in Table 1 is a raw material monomer for the repeating unit represented by general formula (2) above, selected from monomers M-1 to M-5 below. The raw material monomer for repeating unit 2 in Table 1 is a raw material monomer for the repeating unit represented by general formula (1) above, selected from monomers Ma-1 to Ma-4 below. The raw material monomer for repeating unit 3 in Table 1 is a monomer selected from monomers N-1 and N-2 below. The monomers M-1 to M-3, M-5, Ma-1, Ma-4, and N-1 also correspond to raw material monomers for repeating units having an interactive group. Me represents a methyl group.

[0424]

[0425]

[0426]

[0427] <Synthesis Example 1: Synthesis of Resin X-5>

[0428]

[0429] Under a nitrogen stream, 5.33 g of cyclohexanone was placed in a three-necked flask and heated to 85 ° C. Next, into the three-necked flask, 11.92 g of monomer M-3, 6.08 g of monomer Ma-3, 0.58 g of a 20 mass% cyclohexanone solution of polymerization initiator V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and a mixed solution of 21.1 g of cyclohexanone were added dropwise over 4 hours, and after completion of the dropwise addition, the reaction was continued for another 2 hours at 85 ° C. After completion of the reaction, the reaction solution was allowed to cool. Next, the reaction solution after cooling was added dropwise to 300 g of stirred heptane / ethyl acetate (9 / 1), and the powder precipitated by the dropwise addition was collected by filtration and dried to obtain resin X-5 (7.5 g).

[0430] Regarding the above resin X-5, １３ The composition ratio (molar ratio) of the repeating units determined by C-NMR (nuclear magnetic resonance) was: repeating units derived from monomer M-3 / repeating units derived from monomer Ma-3 = 47 / 53. The weight average molecular weight of the resulting resin X-5 measured by GPC was 43,000 in terms of standard polystyrene, and the polydispersity (Mw / Mn) was 1.83.

[0431] [Ionic Compound (A)] The structures of the ionic compounds (A-1 to A-14) shown in Table 2 are shown below. － is CH ３ COO － Represents a group.

[0432]

[0433] [Onium Salt Compound (B)] The structures of the onium salt compounds (B-1 to B-11) shown in Table 2 are shown below. All of the onium salt compounds (B-1 to B-11) are photodecomposable onium salt compounds.

[0434]

[0435]

[0436] [Onium Salt Compound (C)] The structures of the onium salt compounds (C-1 to C-6) shown in Table 2 are shown below.

[0437]

[0438] [Solvents] The solvents shown in Table 2 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 (EL) D-5: γ-butyrolactone (GBL) D-6: Diacetone alcohol

[0439] [Preparation of actinic ray- or radiation-sensitive resin composition] 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 a resist composition. Here, the solids refer to all components other than the solvent. The resulting resist composition was used in the examples and comparative examples.

[0440]

[0441] [Pattern Formation and Evaluation] [Pattern Formation and Evaluation by EUV Exposure: Examples 1-1 to 1-30, Comparative Examples 1-1 to 1-4] <Pattern Formation> 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 Table 3 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 device (manufactured by Exitech, Micro Exposure Tool, NA 0.3, Quadrupol, outer sigma 0.68, inner sigma 0.36). The reticle used was a hexagonal contact hole mask with a pitch of 38 nm and opening dimensions of 22 nm. The exposed resist film was baked at 90° C. for 60 seconds, developed for 30 seconds with a developer shown in Table 3, rinsed with a rinse solution shown in Table 3, and then rotated at 4000 rpm for 30 seconds to obtain a contact hole pattern with a pitch of 38 nm.

[0442] [Resolution Evaluation (Limiting Resolution Evaluation)] Using a critical dimension scanning electron microscope (SEM: Scanning Electron Microscope (CG6300 manufactured by Hitachi High-Technologies Corporation)), 2,000 random holes were observed at each exposure dose, and the average hole diameter and pattern quality were evaluated. The average hole diameter at the minimum exposure dose that satisfied the condition that no unopened holes occurred among the 2,000 observed holes was defined as the limiting resolution. The smaller this value, the better the resolution and performance. The smaller the resolution value, the finer the pattern that can be resolved, indicating high resolution. More specifically, the resolution is preferably 19 nm or less, more preferably 17 nm or less, and even more preferably 16 nm or less. The results are shown in Table 3.

[0443] <CDU Evaluation> The half pitch of 2,000 contact holes was measured at an exposure dose that resulted in a half pitch of 19 nm for the contact hole pattern. The average standard deviation (σ) calculated from the measurement results was tripled (3σ) to evaluate the in-plane hole diameter uniformity (CDU) (nm). The smaller the 3σ value, the higher the in-plane CDU of the diameter of each hole formed in the resist film. A CDU (nm) expressed as 3σ is practical if it is 5.2 nm or less, but 4.8 nm or less is preferred, 4.5 nm or less is more preferred, 4.2 nm or less is even more preferred, and 4.0 nm or less is most preferred. The results are shown in Table 3.

[0444]

[0445] [Developer and Rinse Solution] The solvents shown in Tables 3 and 4 are as follows: E-1: butyl acetate E-2: isopropyl acetate E-3: butyl acetate:n-undecane = 90:10 (mass ratio) E-4: cyclopentanone:n-undecane = 70:30 (mass ratio)

[0446] [Pattern Formation and Evaluation by EB Exposure: Examples 2-1 to 2-30, Comparative Examples 2-1 to 2-4] <Pattern Formation> 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 Table 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 with a resist film. The silicon wafer with 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). A hexagonal array contact hole mask with a pitch of 38 nm and opening dimensions of 22 nm was used as the reticle. The exposed resist film was baked at 90° C. for 60 seconds, developed for 30 seconds with the developer shown in Table 4, rinsed with the rinse solution shown in Table 4, and then spin-dried to obtain a pattern.

[0447] [Evaluation] The resolution and CDU were evaluated using the same method as described above. More specifically, the resolution is preferably 21 nm or less, more preferably 19 nm or less, and even more preferably 18 nm or less. Furthermore, the CDU (nm) expressed as 3σ is practical if it is 5.7 nm or less, but is preferably 5.3 nm or less, more preferably 5.0 nm or less, even more preferably 4.8 nm or less, and most preferably 4.6 nm or less. The results are shown in Table 4.

[0448]

[0449] From the results shown in Tables 3 and 4, it is clear that the resist compositions of the examples are capable of forming patterns with excellent resolution and CDU.

[0450] According to the present invention, there is provided an actinic ray-sensitive or radiation-sensitive resin composition that is capable of forming a pattern excellent in resolution and CDU in the formation of an ultrafine pattern (for example, a line-and-space pattern having a line width of 25 nm or less, a contact hole pattern having a half pitch of 25 nm or less, etc.). Furthermore, according to the present invention, there are provided a resist film, a pattern forming method, and a method for manufacturing an electronic device, which use the actinic ray-sensitive or radiation-sensitive resin composition.

[0451] 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. 2023-170257) filed on September 29, 2023, the contents of which are incorporated herein by reference.

Claims

1. An actinic ray- or radiation-sensitive resin composition comprising: a resin (X) containing a repeating unit represented by the following general formula (1) and a repeating unit having an interactive group; an ionic compound (A) having a non-decomposable organic cation that interacts with the interactive group in the resin (X) and is not decomposed by exposure to actinic rays or radiation; an onium salt compound (B) that generates an acid by exposure to actinic rays or radiation; and a solvent, wherein the acidity of the conjugate acid of the anion of the ionic compound (A) is different from that of the conjugate acid of the onium salt compound (B). In the general formula (1), X represents a halogen atom, a fluorinated alkyl group, or a fluorinated cycloalkyl group. ０ represents a hydrogen atom or a monovalent organic group. １ represents a monovalent substituent. ０ and R １ may be bonded to form a ring.

2. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein the conjugate acid of the anion of the onium salt compound (B) is a stronger acid than the conjugate acid of the anion of the ionic compound (A).

3. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, further comprising an onium salt compound (C) which generates an acid weaker than the conjugate acid of the anion of the onium salt compound (B) upon exposure to actinic rays or radiation.

4. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the non-decomposable organic cation of the ionic compound (A) is an ammonium cation, a pyridinium cation, an imidazolium cation, or a phosphonium cation.

5. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the conjugate acid of the anion of the onium salt compound (B) is an inorganic acid or an organic acid stronger than tetrafluoroboric acid.

6. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 3, wherein the conjugate acid of the anion of the onium salt compound (C) is tetrafluoroboric acid or an inorganic or organic acid weaker than tetrafluoroboric acid.

7. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the conjugate acid of the anion of the onium salt compound (B) is hexafluorophosphoric acid, fluoroantimonic acid, a fluorinated alkylsulfonimide, or a fluorinated alkylsulfonic acid.

8. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the cation of the onium salt compound (B) is a sulfonium cation or an iodonium cation.

9. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 3, wherein the conjugate acid of the anion of the onium salt compound (C) is a boric acid compound having an aryl group or a heteroaryl group.

10. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 3, wherein the cation of the onium salt compound (C) is a sulfonium cation or an iodonium cation.

11. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the resin (X) has a repeating unit represented by the following general formula (2): In general formula (2), R ３ represents a hydrogen atom or a monovalent organic group. ４ represents 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. ３ may be bonded to each other to form a ring.

12. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1 or 2, wherein the interactive group in the repeating unit having an interactive group is a phenolic hydroxyl group.

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

14. 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 using a developer.

15. A method for manufacturing an electronic device, comprising the pattern formation method according to claim 14.

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