Photosensitive composition, resist film, pattern forming method, and method for manufacturing electronic device

Abstract

The present invention addresses the problem of providing a photosensitive composition with which it is possible to form a pattern having a small LCDU. A photosensitive composition according to the present invention contains a resin that has a repeating unit which is derived from a monomer containing an onium base that is composed of an anionic group and a cation. The resin has an organometallic structure, or the photosensitive composition comprises an organometallic compound that is different from the resin. The acid dissociation constant of a compound that is obtained by replacing the cation with a proton in the monomer is -1.0 or less. The cation has a structure that is changeable by the action of an acid. When the cation before the structure is changed by the action of an acid is defined as a cation X, and the cation after the structure is changed by the action of the acid is defined as a cation Y, the integrated value of the molar absorption coefficients of the cation Y at wavelengths of 200-450 nm is larger than the integrated value of the molar absorption coefficients of the cation X at wavelengths of 200-450 nm, and the onium base that is composed of the anionic group and the cation Y generates an acid when irradiated with light having a wavelength of 200-450 nm.

Description

Photosensitive composition, resist film, pattern forming method, and method for manufacturing electronic device

[0001] The present invention relates to a photosensitive composition, a resist film, a pattern forming method, and a method for manufacturing 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 is first decomposed by light irradiation to generate an acid. Then, during a post-exposure bake (PEB) process or the like, 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 a developer. Development is then performed, for example, using a basic aqueous solution. This removes the exposed areas to obtain the desired pattern. In order to miniaturize semiconductor elements, lithography methods using light of various wavelengths, such as ultraviolet light, extreme ultraviolet (EUV) light, and electron beam (EB), have been developed in recent years.

[0003] For example, Patent Document 1 proposes a method of forming a pattern by multi-stage exposure using light with a short wavelength such as EUV light and light with a longer wavelength.

[0004] Patent No. 6820233

[0005] In recent years, there has been a demand for a higher level of improvement in local critical dimension uniformity (LCDU). When the present inventors applied the composition described in the above document to the above process, they found that there is room for further investigation in terms of the LCDU.

[0006] Therefore, an object of the present invention is to provide a photosensitive composition that can form a pattern with a small LCDU. Another object of the present invention is to provide a pattern formation method and an electronic device manufacturing method that involve the photosensitive composition.

[0007] As a result of extensive research into solving the above problems, the present inventors have found that the problems can be solved by the following configuration.

[0008] [1] A photosensitive composition comprising a resin having a repeating unit derived from a monomer containing an onium salt group composed of an anionic group and a cation, as represented by formula (1) described below, wherein the resin has an organometallic structure, or the photosensitive composition contains an organometallic compound different from the resin, wherein the compound in the monomer, obtained by substituting the cation in formula (1) with a proton, has an acid dissociation constant of −1.0 or less, the cation is a cation whose structure changes under the action of an acid, and wherein the cation before its structure changes under the action of an acid is defined as cation X and the cation after its structure changes under the action of an acid is defined as cation Y, the integrated value of the molar absorption coefficient of the cation Y in a wavelength range of 200 to 450 nm is larger than the integrated value of the molar absorption coefficient of the cation X in a wavelength range of 200 to 450 nm, and the onium salt group composed of the anionic group and the cation Y generates an acid when irradiated with light having a wavelength of 200 to 450 nm. [2] The photosensitive composition according to [1], which satisfies at least one of requirements Q1 and Q2. Requirement Q1: The photosensitive composition contains an acid diffusion controller different from the resin. Requirement Q2: The resin has a repeating unit that has acid diffusion control properties. [3] The photosensitive composition according to [1] or [2], in which the cation X is a cation that undergoes a structural change under the action of an acid to form a multiple bond. [4] The photosensitive composition according to any one of [1] to [3], in which the cation X includes at least one selected from the group consisting of cations represented by formula (CT-1) and formula (CT-2) described below. [5] The photosensitive composition according to any one of [1] to [4], in which the metal atom in the organometallic structure and the organometallic compound is at least one selected from the group consisting of Sn, Bi, Ge, Si, As, Se, Sb, Te, Pb, and Po. [6] The photosensitive composition according to any one of [1] to [5], wherein the repeating unit derived from a monomer containing an onium salt group composed of an anionic group and a cation, represented by formula (1), is a repeating unit represented by formula (UA-1) described below.[7] The photosensitive composition according to any one of [1] to [6], wherein the organometallic structure and the organometallic compound have a partial structure represented by formula (2) described below. [8] A resist film formed using the photosensitive composition according to any one of [1] to [7]. [9] A pattern formation method comprising the steps of: forming a resist film on a substrate using the photosensitive composition according to any one of [1] to [7]; irradiating the resist film with light having a wavelength of less than 200 nm to perform patternwise exposure; exposing the patternwise exposed resist film with light having a wavelength of 200 to 450 nm; and developing the exposed resist film using a developer.

[10] The pattern formation method according to [9], wherein an acid is generated by irradiation with the light having a wavelength of less than 200 nm, and the acid changes the structure of the cation X to generate the cation Y, and an acid is generated from an onium salt group consisting of the anionic group and the cation Y by irradiation with the light having a wavelength of 200 to 450 nm.

[11] The pattern forming method according to [9] or

[10] , wherein the developer is an organic solvent-based developer.

[12] A method for manufacturing an electronic device, comprising the pattern forming method according to any one of [9] to

[11] .

[0009] According to the present invention, a photosensitive composition capable of forming a pattern with a small LCDU can be provided. The present invention also provides a pattern formation method and an electronic device manufacturing method related to the photosensitive composition.

[0010] The present invention will be described in detail below. The following description of the components may be based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.

[0011] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. Furthermore, in this specification, when two or more types of a certain component are present, the "content" of that component means the total content of those two or more components. In this specification, in a numerical range described in stages, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in a numerical range described in this specification, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the Examples. In this specification, a combination of two or more preferred embodiments is a more preferred embodiment.

[0012] In this specification, "actinic rays" or "radiation" refers to, for example, the bright line spectrum of a mercury lamp, far ultraviolet rays typified by excimer lasers, extreme ultraviolet rays (EUV light), X-rays, and electron beams (EB). In this specification, "light" refers to actinic rays or radiation. In this specification, "exposure" refers to not only exposure using the bright line spectrum of a mercury lamp, far ultraviolet rays typified by excimer lasers, extreme ultraviolet rays (EUV), and X-rays, but also drawing using particle beams such as electron beams and ion beams, unless otherwise specified.

[0013] In this specification, "ppm" means "parts-per-million (10 －６ ) and "ppb" stands for "parts-per-billion (10 －９ ) and "ppt" stands for "parts-per-trillion (10 －１２ In this specification, 1 Å means 1×10 －１０ m.

[0014] In this specification, the weight average molecular weight (Mw), number average molecular weight (Mn), and polydispersity index (also referred to as "PDI") (Mw / Mn) are defined as polystyrene equivalent values ​​measured by Gel Permeation Chromatography (GPC) measurement 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).

[0015] In this specification, unless otherwise specified, the boiling point means the boiling point at 1 atmosphere (760 mmHg).

[0016] In this specification, "(meth)acrylic acid" is a concept that encompasses both acrylic acid and methacrylic acid, "(meth)acryloyl group" is a concept that encompasses both acryloyl group and methacryloyl group, "(meth)acrylate" is a concept that encompasses both acrylate and methacrylate, and "(meth)acrylamide group" is a concept that encompasses both acrylamide group and methacrylamide group.

[0017] In this specification, when there are a plurality of substituents, linking groups, etc. (hereinafter referred to as "substituents, etc.") represented by a specific symbol, or when a plurality of substituents, etc. are simultaneously specified, it means that the respective substituents, etc. may be the same or different from each other. This also applies to the specification of the number of substituents, etc.

[0018] In this specification, the bonding direction of a divalent linking group 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-. That is, the compound may be either "X-CO-O-Z" or "X-O-CO-Z".

[0019] "Solid content" refers to the components that form the resist film, and does not include solvents. In addition, any component that forms the resist film is considered to be a solid content even if it is in liquid form.

[0020] [Photosensitive Composition] The photosensitive composition of the present invention (hereinafter also simply referred to as "photosensitive composition") will be described in detail below. The photosensitive composition of the present invention is a photosensitive composition containing a resin having a repeating unit derived from a monomer containing an onium salt group consisting of an anionic group and a cation, represented by the following formula (1) (hereinafter also simply referred to as "the onium salt group represented by formula (1)"), wherein the resin has an organometallic structure, or the photosensitive composition contains an organometallic compound different from the resin, the acid dissociation constant of a compound in the monomer obtained by substituting the cation in formula (1) with a proton is -1.0 or less, the cation is a cation whose structure changes under the action of an acid, and when the cation before the structure changes under the action of an acid is represented by cation X and the cation after the structure changes under the action of an acid is represented by cation Y, the integrated value of the molar absorption coefficient of the cation Y at a wavelength of 200 to 450 nm is larger than the integrated value of the molar absorption coefficient of the cation X at a wavelength of 200 to 450 nm, The photosensitive composition is one in which an onium salt group consisting of the anionic group and the cation Y generates an acid when irradiated with light having a wavelength of 200 to 450 nm.

[0021] While the reason why the photosensitive composition having the above configuration can solve the problems of the present invention is not entirely clear, the inventors speculate as follows. The following speculation does not limit the mechanism by which the effect is obtained. In other words, even if the effect is obtained by a mechanism other than the one described below, it is still within the scope of the present invention. The resin in the photosensitive composition of the present invention (hereinafter also referred to as the "specific resin") contains a cation X that undergoes a structural change under the action of an acid, thereby increasing the molar absorption coefficient for light with a wavelength of 200 to 450 nm. Therefore, when acid is generated in a specific region of the system by, for example, patterned exposure with short-wavelength light, the structure of the cation X changes under the action of the acid, thereby exhibiting photosensitivity to light with a wavelength of 200 to 450 nm. Furthermore, when light with a wavelength of 200 to 450 nm is irradiated, an acid is generated from an onium base containing the structurally changed cation Y, and the acid multiplies by chemical amplification. At this time, decomposition of the cation Y converts the ionic substance into a nonionic substance, thereby reducing polarity. Furthermore, the hydrophilic acid groups derived from the onium salt group in the resin thus generated react with the organometallic structure or organometallic compound in the photosensitive composition, thereby hydrophobizing the resin. This action reduces the polarity of the photosensitive composition in the exposed area, resulting in a polarity contrast. In the photosensitive composition of the present invention, the resin supports the onium salt group represented by formula (1), suppressing acid diffusion and resulting in a pronounced polarity contrast. Furthermore, the onium salt group represented by formula (1) has a low acid dissociation constant and generates an acid that can react efficiently with the organometallic structure or organometallic compound, resulting in excellent sensitivity. As a result, it is believed that the photosensitive composition of the present invention can form a pattern with a small LCDU. The photosensitive composition of the present invention exhibits excellent effects, particularly in a pattern formation method using a multi-step exposure method in which the photosensitive composition is pattern-exposed with light having a wavelength of less than 200 nm and then irradiated with light having a wavelength of 200 to 450 nm. Hereinafter, the ability to form a pattern with a smaller LCDU using the photosensitive composition will also be simply referred to as "the effect of the present invention being superior." The constitution of the photosensitive composition will be described in detail below.

[0022] [Specific Resin] The photosensitive composition contains a specific resin, which has a repeating unit (hereinafter also referred to as "repeating unit U1") derived from a monomer containing an onium salt group (hereinafter also referred to as "onium salt group X") represented by formula (1) consisting of an anionic group and a cation (corresponding to cation X described below).

[0023] <Repeating Unit U1> The specific resin has a repeating unit U1 derived from a monomer containing an onium salt group X represented by formula (1). The polymerizable group contained in the monomer containing an onium salt group X is preferably a radically polymerizable group, and more preferably an ethylenic double bond-containing group. Examples of the ethylenic double bond-containing group include a (meth)acryloyl group, a (meth)acrylamide group, a vinyl group, a styryl group, an allyl group, and a vinyl ether group, and a (meth)acryloyl group, a vinyl group, or a styryl group is preferred.

[0024] Formula (1) *-A － C ＋ In formula (1), A － represents an anionic group, C ＋ represents a cation, and * represents a bonding site.

[0025] In formula (1), A － Examples of the anionic group represented by the formula (I) include a sulfonate anionic group, a carboxylate anionic group, a phosphonate anionic group, a phosphate anionic group, a sulfonimide anionic group, a sulfonamide anionic group, and a methide anionic group. The sulfonate anionic group (—SO ３ － ) is preferred.

[0026] C in formula (1) of the monomer containing the onium base X ＋The acid dissociation constant (pKa) of the compound in which the cation represented by the formula (I) is replaced with a proton is -1.0 or less. If the pKa exceeds -1.0, the acid group (-AH) derived from the onium base X is less likely to react with the organometallic structure or organometallic compound described below, which is undesirable as it deteriorates the LCDU. The pKa is preferably -1.5 or less, more preferably -2.0 or less, in order to achieve better effects of the present invention. There is no particular lower limit, but it is often -10.0 or more, and -6.0 or more is more preferred. In this specification, pKa refers to the pKa in an aqueous solution, and specifically refers to a value calculated using the following software package 1 based on a database of Hammett's substituent constants and known literature values. All pKa values ​​described in this specification are values ​​calculated using this software package. Software package 1: Advanced Chemistry Development (ACD / Labs) Software V8.14 for Solaris (1994-2007 ACD / Labs). If the pKa in aqueous solution cannot be calculated, the "pKa in dimethyl sulfoxide (DMSO) solution" is used. If the pKa cannot be calculated using the above method, the value obtained by molecular orbital calculation is used. As a specific method using molecular orbital calculation, the value obtained using Gaussian 16 based on DFT is used. If the compound has multiple pKas, it is sufficient that at least one pKa satisfies the above requirements, and it is preferable that all pKas satisfy the above requirements.

[0027] In formula (2), C ＋ represents a cation. ＋ is a cation whose structure changes under the action of an acid. When the cation before its structure changes under the action of an acid is designated as cation X and the cation after its structure changes under the action of an acid is designated as cation Y, the integrated value of the molar absorption coefficient of cation Y at a wavelength of 200 to 450 nm (integrated value FY) is greater than the integrated value of the molar absorption coefficient of cation X at a wavelength of 200 to 450 nm (integrated value FX). In other words, when the value of (integrated value FY - integrated value FX) is 0 L mol －１・cm －１ The above value (integrated value FY - integrated value FX) is 500,000 L mol －１ ・cm －１ Preferably, 1,000,000 L / mol or more. －１ ・cm －１ More preferably, 3,000,000 L mol or more. －１ ・cm －１ The upper limit is not particularly limited, but is preferably 8,000,000 L mol －１ ・cm －１ In most cases, it is less than 5,000,000 L / mol. －１ ・cm －１ The integrated value FY is preferably 1,500,000 to 9,000,000 L·mol. －１ ・cm －１ is preferred, and 2,000,000 to 8,000,000 L mol －１ ・cm －１ The integrated value FX is more preferably 500,000 to 6,000,000 L·mol. －１ ・cm －１ is preferred, and 1,000,000 to 4,000,000 L mol －１ ・cm －１ is more preferred.

[0028] The integrated value of the molar absorption coefficient of each cation is determined by the following method. The peak area of ​​the absorption spectrum of the cation in the wavelength range of 200 to 450 nm is calculated as the integrated value of the molar absorption coefficient at wavelengths of 200 to 450 nm. The absorption spectrum and peak area are determined by TD-DFT calculation using the electronic state calculation software Gaussian 16 provided by Gaussian under B3LYP / 6-31+G(d), IEFPCM method, and acetonitrile solvent conditions, and by UV-Vis spectrum calculation using the calculation software GaussView under conditions of a half-width of 0.2 eV and an output wavelength interval of 1 nm.

[0029] Structural changes from the cation X to the cation Y include the formation of a multiple bond, substitution of a substituent, and hydrolysis, with the formation of a multiple bond being preferred. That is, the cation X is preferably a cation that undergoes a structural change under the action of an acid to form a multiple bond. Examples of the multiple bond include carbon-carbon multiple bonds such as a carbon-carbon double bond (C═C) and a carbon-carbon triple bond (C≡C), a carbon-oxygen double bond (C═O), and a carbon-sulfur double bond (C═S). In terms of achieving superior effects of the present invention, a carbon-carbon multiple bond is preferred, and a carbon-carbon double bond (C═C) is more preferred. It is preferable that the multiple bond is not contained in a ring structure or is contained in an aliphatic ring. In other words, it is preferable that the multiple bond does not constitute part of an aromatic ring.

[0030] In view of the superior effects of the present invention, it is preferable that the ClogP value of cation Y is larger than the ClogP value of cation X. The difference ΔClogP between the ClogP values ​​of cation Y and cation X (ClogP value of cation Y - ClogP value of cation X) is preferably 0.5 or more, more preferably 1.0 or more, and even more preferably 1.2 or more. There is no particular upper limit, but it is often 5.0 or less. In this specification, the ClogP value refers to the value obtained by calculating the common logarithm logP of the partition coefficient P between 1-octanol and water. Known methods and software can be used to calculate the ClogP value, but unless otherwise specified, in the present invention, the structure is drawn using ChemDraw Professional (version 22.2.0.3300) manufactured by PerkinElmer, and the value calculated using the above software is used. For example, the ClogP value of a cation is calculated by drawing the structure of the cation using the software. The ClogP value of cation X is preferably 2.0 to 10.0, more preferably 3.0 to 9.0, and even more preferably 4.0 to 8.0. The ClogP value of cation Y is preferably 3.0 to 13.0, more preferably 4.0 to 12.0, and even more preferably 5.0 to 11.0.

[0031] The onium base X is preferably a group that generates an acid when irradiated with light having a wavelength of less than 200 nm. In this case, pattern exposure with a wavelength of less than 200 nm can cause the cation X to undergo a structural change to a cation Y due to the action of the acid derived from the onium base X. Examples of the light having a wavelength of less than 200 nm include electron beams (EB), extreme ultraviolet light (EUV), ArF excimer lasers, and F ２ Examples include excimer lasers and X-rays. When the onium base X does not generate an acid when irradiated with light having a wavelength of less than 200 nm, the photosensitive composition preferably contains a photoacid generator, which will be described later.

[0032] The cations X and Y will be described in detail below.

[0033] (Cation X) As described above, the cation X is a cation that changes into the cation Y under the action of an acid, and is represented by C in formula (1). ＋ The cation X has the same meaning as the cation represented by the formula (S-1) below. The cation X has a moiety whose structure changes when acted upon by an acid. Preferred embodiments of the structural change are as described above. Examples of the structural change moiety include groups represented by the following formulas (S-1) to (S-3).

[0034]

[0035] In formulas (S-1) to (S-3), R Ｓ１ ~R Ｓ４each independently represents a hydrocarbon group having 1 to 20 carbon atoms, which may have a hydrogen atom or a heteroatom. The hydrocarbon group has 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. The heteroatom that the hydrocarbon group may have is not particularly limited, but is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, or a metal atom. Examples of the metal atom include metal atoms in the organometallic structures described below, and the same applies to preferred embodiments. The hydrocarbon group that may have a heteroatom is preferably an aliphatic hydrocarbon group that may have a substituent, or an aromatic ring group that may have a substituent. The aliphatic hydrocarbon group may be linear, branched, or cyclic. The aliphatic hydrocarbon group preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms. The aromatic ring group may be either monocyclic or polycyclic. Furthermore, it may be either an aromatic hydrocarbon group or an aromatic heterocyclic group. The aromatic ring group preferably has 3 to 12 carbon atoms, more preferably 5 to 10 carbon atoms. Examples of the substituents that the aliphatic hydrocarbon group and aromatic ring group may have include alkyl groups (e.g., having 1 to 15 carbon atoms), aryl groups (e.g., having 6 to 14 carbon atoms), heteroaryl groups (e.g., having 2 to 10 carbon atoms), alkoxy groups (e.g., having 1 to 15 carbon atoms), aryloxy groups (e.g., having 6 to 14 carbon atoms), acyl groups (e.g., having 2 to 15 carbon atoms), alkylthio groups (e.g., having 1 to 15 carbon atoms), arylthio groups (e.g., having 6 to 14 carbon atoms), ester groups (-OCOR' or -COOR': R' is a hydrocarbon group (preferably having 1 to 6 carbon atoms) that may have a substituent), lactone groups, carboxy groups, hydroxy groups, mercapto groups, amino groups, amido groups, nitro groups, phosphino groups, halogen atoms, cyano groups, and organometallic groups. The above-mentioned substituents may further have a substituent, if possible. For example, the alkyl group or aryl group in the substituent may have a halogen atom as a substituent, forming a halogenated alkyl group or a halogenated aryl group such as a perfluoroalkyl group. The above-mentioned organometallic groups include -M-(R) ｍExamples of the metal atom represented by M include a metal atom, R includes a substituent, and m includes the valence of the metal minus 1. Examples of the metal atom represented by M include metal atoms in the organometallic structures and organometallic compounds described below, and the preferred embodiments are also the same. Examples of the substituent represented by R include the substituent represented by R in the group represented by formula (2) described below, and the preferred embodiments are also the same.

[0036] R Ｓ１ and R Ｓ２ may be bonded to each other via a single bond or a divalent linking group to form a ring, R Ｓ３ and R Ｓ４ may be bonded to each other via a single bond or a divalent linking group to form a ring. Examples of the divalent linking group include -O-, -S-, -CO-, -NR Ｎ -, -SO-, -SO ２ -, alkylene groups (preferably having 1 to 3 carbon atoms), arylene groups (preferably having 6 to 10 carbon atoms), and combinations thereof. Ｎ represents a hydrogen atom or a hydrocarbon group (preferably having 1 to 6 carbon atoms). The ring is preferably an aliphatic heterocycle containing at least an oxygen atom or a sulfur atom.

[0037] In formulas (S-1) to (S-3), R Ｓ５ and R Ｓ６ R each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom. Ｓ５ and R Ｓ６ The definition and preferred embodiments of the hydrocarbon group having 1 to 20 carbon atoms which may have a hetero atom and is represented by R Ｓ１ ~R Ｓ４ The hydrocarbon group is the same as the hydrocarbon group having 1 to 20 carbon atoms which may have a hetero atom and is represented by the following formula:

[0038] R Ｓ５ and R Ｓ６ may be bonded to each other via a single bond or a divalent linking group to form a ring. Examples of the divalent linking group include R Ｓ１ and R Ｓ２Examples of the divalent linking group when the groups bond to each other include the groups exemplified above. The ring is preferably an aliphatic heterocycle containing at least an oxygen atom or a sulfur atom.

[0039] In formulas (S-1) to (S-3), X Ｓ１ and X Ｓ２ each independently represents an oxygen atom or a sulfur atom, and preferably an oxygen atom.

[0040] In formulas (S-1) to (S-3), Y Ｓ１ and Y Ｓ２ each independently represents a hydrocarbon group having 1 to 20 carbon atoms and containing a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom. However, a heteroatom is located at the linking site of the hydrocarbon group having 1 to 20 carbon atoms and containing a heteroatom. The heteroatom at the linking site of the hydrocarbon group having a heteroatom is preferably an oxygen atom or a sulfur atom, and more preferably an oxygen atom. The linking site is the Y Ｓ１ or Y Ｓ２ The hydrocarbon group having a hetero atom may further have a hetero atom in addition to the linking portion. The hydrocarbon group having a hetero atom includes, for example, -X Ｓ３ -L Ｓ１ -R Ｓ７ A group represented by the following formula is preferred. X Ｓ３ represents an oxygen atom or a sulfur atom, and an oxygen atom is preferred. Ｓ１ is a single bond, -SO ２ represents -, -CO-, or -CO-O-. Ｓ７ represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Ｓ７ The definition and preferred embodiments of the group represented by R Ｓ５ and R Ｓ６ is the same as the group represented by Ｓ１ and Y Ｓ２ Among them, -X Ｓ３ -L Ｓ１ -R Ｓ７ A group represented by the following formula (I), a hydroxy group, or a mercapto group is preferred.

[0041] The groups represented by formulae (S-1) to (S-3) are preferably groups whose structure changes to groups represented by formulae (S-1') to (S-3') by the action of an acid, respectively.

[0042]

[0043] In formulas (S-1') to (S-3'), R Ｓ１ ~R Ｓ４ is the same as each group in formulas (S-1) to (S-3). Ｓ３ represents an oxygen atom or a sulfur atom.

[0044] Cations Represented by Formula (CT-1) and Cations Represented by Formula (CT-2) Cation X is preferably a sulfonium cation or an iodonium cation. The sulfonium cation is preferably a cation represented by Formula (CT-1). The iodonium cation is preferably a cation represented by Formula (CT-2).

[0045]

[0046] In formula (CT-1), R １ and R ２ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom. １ represents a single bond or a divalent linking group. １ represents a divalent aromatic ring group, and a represents an integer of 0 or more. ３ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom. ３ may be bonded to each other via a single bond or a divalent linking group to form a ring. ＋ Two or more groups directly bonded to L may be bonded to each other via a single bond or a divalent linking group to form a ring. ２ represents a single bond, an ethenylene group, an ethynylene group, a carbonyl group, a sulfinyl group, or a sulfonyl group. １represents a group represented by any one of formulas (S-1) to (S-3). b represents 0 or 1. T １ represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, or a group represented by formula (T1). １ and T １ and may be bonded to each other via a single bond or a divalent linking group to form a ring. Ｔ１ represents a single bond, an ethenylene group, an ethynylene group, a carbonyl group, a sulfinyl group, or a sulfonyl group. Ｔ１ represents an aromatic ring group having a valence of e+f+1, and e represents an integer of 0 or more. Ｔ１ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom. Ｔ１ may be bonded to each other via a single bond or a divalent linking group to form a ring. Ｔ１ R each independently represents a group represented by any one of the above formulas (S-1) to (S-3). Ｔ２ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a hydrogen atom or a heteroatom, and f represents an integer of 0 to 4, provided that b+f is an integer of 1 to 4. In formula (CT-2), R ４ represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom. ３ represents a single bond or a divalent linking group. ２ represents a c+2-valent aromatic ring group, and c represents an integer of 0 or more. ５ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom. ５ may be bonded to each other to form a ring. ５ They may be bonded to each other via a single bond or a divalent linking group. ＋The two groups directly bonded to L may be bonded to each other via a single bond or a divalent linking group to form a ring. ４ represents a single bond, an ethenylene group, an ethynylene group, a carbonyl group, a sulfinyl group, or a sulfonyl group. ２ represents a group represented by any one of the above formulas (S-1) to (S-3). ２ represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, or a group represented by the above formula (T1). ２ and T ２ and may be bonded to each other via a single bond or a divalent linking group to form a ring. d represents 0 or 1, provided that d+f is an integer of 1 to 4.

[0047] In formula (CT-1), R １ and R ２each independently represents a hydrocarbon group having 1 to 20 carbon atoms, which may have a heteroatom. The hydrocarbon group preferably has 1 to 14 carbon atoms, and more preferably 3 to 10 carbon atoms. The heteroatom that the hydrocarbon group may have is not particularly limited, but is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, or a metal atom. Examples of the metal atom include metal atoms in the organometallic structures described below, and the same applies to preferred embodiments. The hydrocarbon group that may have a heteroatom is preferably an aromatic ring group that may have a substituent or an aliphatic hydrocarbon group that may have a substituent, and more preferably an aromatic ring group that may have a substituent. That is, the hydrocarbon group that has 1 to 20 carbon atoms, which may have a heteroatom, is preferably an aromatic ring group that has 1 to 20 carbon atoms, which may have a substituent. The aromatic ring group may be either monocyclic or polycyclic, and is preferably monocyclic. The aromatic ring group may be any of aromatic hydrocarbon groups such as phenyl, naphthyl, and anthryl groups, and aromatic heterocyclic groups such as pyrrole, pyridine, furan, thiophene, indole, benzofuran, and benzothiophene ring groups, with aromatic hydrocarbon groups being preferred, and phenyl being more preferred. The aliphatic hydrocarbon group may be linear, branched, or cyclic. Substituents that the aliphatic hydrocarbon group and aromatic ring group may have include the R Ｓ１ ~R Ｓ４ Examples of the substituent include the groups exemplified as the substituent that the aliphatic hydrocarbon group and aromatic ring group represented by the formula (I) may have, and an alkyl group, an alkoxy group, a halogen atom, or an organometallic group is preferred. The details of the organometallic group are as described above.

[0048] In formula (CT-1), L １ represents a single bond or a divalent linking group. Examples of the divalent linking group include —O—, —CO—, —NR Ｎ -, -S-, -SO ２ -, and combinations thereof, as well as divalent hydrocarbon groups having 1 to 20 carbon atoms which may have a heteroatom. Ｎrepresents a hydrogen atom or a hydrocarbon group (preferably having 1 to 6 carbon atoms). The divalent hydrocarbon group having 1 to 20 carbon atoms which may have a hetero atom includes R １ and R ２ Examples of such groups include groups obtained by removing one hydrogen atom from a hydrocarbon group having 1 to 20 carbon atoms and optionally having a hetero atom, represented by the following formula: １ is preferably a single bond.

[0049] In formula (CT-1), Ar １ represents an (a+2) valent aromatic ring group. The aromatic ring group is a group formed by removing (a+2) hydrogen atoms from an aromatic ring. The aromatic ring may be either a monocyclic or polycyclic ring, with a monocyclic ring being preferred. The aromatic ring group preferably has 5 to 12 ring-member atoms, more preferably 6 to 10. Examples of the aromatic ring include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, and an anthracene ring, and aromatic heterocycles such as a pyridine ring, a pyridazine ring, a pyridine ring, a furan ring, a thiophene ring, an indole ring, a benzofuran ring, and a benzothiophene ring, with an aromatic hydrocarbon ring being preferred, and a benzene ring being more preferred.

[0050] In formula (CT-1), a represents an integer of 0 or more, preferably an integer of 0 to 4, and more preferably an integer of 0 to 2.

[0051] In formula (CT-1), R ３ R each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a hetero atom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom. ３ The definition and preferred embodiments of the hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, represented by R Ｓ１ ~R Ｓ４ When a is an integer of 2 or more, a plurality of R ３ They may be bonded to each other via a single bond or a divalent linking group to form a ring. Examples of the divalent linking group include -O-, -S-, -CO-, -NR Ｎ -, -S-, -SO ２-, an alkylene group (preferably having 1 to 3 carbon atoms), an arylene group, and a combination thereof. Ｎ represents a hydrogen atom or a hydrocarbon group (preferably having 1 to 6 carbon atoms). The ring is preferably an aliphatic ring which may have a hetero atom.

[0052] S ＋ Two or more groups directly bonded to L may be bonded to each other via a single bond or a divalent linking group to form a ring. １ represents a divalent linking group, R １ , R ２ , and L １ two or more groups selected from the group consisting of may be bonded to each other via a single bond or a divalent linking group to form a ring, and L １ When represents a single bond, R １ , R ２ , and Ar １ Two or more groups selected from the group consisting of may be bonded to each other via a single bond or a divalent linking group to form a ring. ３ Examples of the divalent linking group that bonds to each other include the groups exemplified above.

[0053] In formula (CT-1), L ２ represents a single bond, an ethenylene group, an ethynylene group, a carbonyl group, a sulfinyl group, or a sulfonyl group, and is preferably a single bond.

[0054] In formula (CT-1), S １ represents a group represented by any one of the above formulas (S-1) to (S-3), and is preferably a group represented by formula (S-1) or (S-2) in that the effects of the present invention are more excellent.

[0055] In formula (CT-1), b represents 0 or 1, and is preferably 1.

[0056] In formula (CT-1), T １ represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, or a group represented by formula (T1) described below. １ The definition and preferred embodiments of the hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, represented by R１ and R ２ The hydrocarbon group is the same as the hydrocarbon group having 1 to 20 carbon atoms which may have a hetero atom and is represented by the following formula: １ As the group, an aromatic ring group having 1 to 20 carbon atoms, which may have a substituent, is preferred.

[0057] Ar １ and T １ and may be bonded to each other via a single bond or a divalent linking group to form a ring. １ represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, Ar １ and T １ and may be bonded to each other via a single bond or a divalent linking group to form a ring. １ represents a group represented by formula (T1) described later, Ar １ and any group in formula (T1) may be bonded to each other via a single bond or a divalent linking group to form a ring. Examples of the divalent linking group include R ３ Examples of the divalent linking group that can be used to bond the rings to each other include the groups exemplified above. The ring is preferably an aliphatic ring.

[0058] In formula (T1), L Ｔ１ represents a single bond, an ethenylene group, an ethynylene group, a carbonyl group, a sulfinyl group, or a sulfonyl group, and is preferably a single bond.

[0059] In formula (T1), Ar Ｔ１ represents an e+f+1 valent aromatic ring group. The e+f+1 valent aromatic ring group is a group obtained by removing e+f+1 hydrogen atoms from an aromatic ring. The definition and preferred embodiments of the aromatic ring are as follows: Ar １ The aromatic ring is the same as the aromatic ring constituting the aromatic ring group represented by the formula:

[0060] In formula (T1), e represents an integer of 0 or more, preferably an integer of 0 to 4, and more preferably an integer of 0 to 2.

[0061] In formula (T1), R Ｔ１each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom. Ｔ１ R may be bonded to each other via a single bond or a divalent linking group to form a ring. Ｔ１ and a group represented by R Ｔ１ The definition and preferred embodiment of the embodiment in which R ３ and a group represented by R ３ This is the same as when they bond to each other to form a ring.

[0062] In formula (T1), S Ｔ１ each independently represents a group represented by any one of the above formulas (S-1) to (S-3), and a group represented by formula (S-1) or a group represented by formula (S-2) is preferred in terms of better effects of the present invention.

[0063] In formula (T1), R Ｔ２ R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom. Ｔ２ The definition and preferred embodiments of the hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, represented by the following formula, are as follows: １ The hydrocarbon group is the same as the hydrocarbon group having 1 to 20 carbon atoms which may have a hetero atom and is represented by the following formula:

[0064] In formula (T1), f represents an integer of 0 to 4, and is preferably 0 or 1.

[0065] In formula (CT-1), b+f is an integer of 1 to 4. That is, when b is 1, f is an integer of 0 to 3, and when b is 0, f is an integer of 1 to 4. b+f is preferably 1 or 2, and more preferably 1. In formula (CT-1), T １ represents a hydrocarbon group having 1 to 20 carbon atoms which may have a hydrogen atom or a hetero atom, and f is 0.

[0066] In formula (CT-2), R ４ , L ３ , L ４, c, S ２ , and T ２ The definition and preferred embodiments of the group represented by the formula (CT-1) are respectively １ , L １ , L ２ , a, S １ , and T １ is the same as the group represented by

[0067] In formula (CT-2), Ar ２ represents a c+2 valent aromatic ring group. The c+2 valent aromatic ring group is a group obtained by removing c+2 hydrogen atoms from an aromatic ring. The definition and preferred embodiments of the aromatic ring are as follows: Ar １ The aromatic ring is the same as the aromatic ring constituting the aromatic ring group represented by the formula:

[0068] I ＋ Two or more groups directly bonded to L may be bonded to each other via a single bond or a divalent linking group to form a ring. ３ represents a divalent linking group, R ４ and L ３ and may be bonded to each other via a single bond or a divalent linking group to form a ring, ３ When represents a single bond, R ４ and Ar ２ and may be bonded to each other via a single bond or a divalent linking group to form a ring. Examples of the divalent linking group include R ３ Examples of the divalent linking group that bonds to each other include the groups exemplified above.

[0069] In formula (CT-2), R ５ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom. ５ R may be bonded to each other via a single bond or a divalent linking group to form a ring. ５ and a group represented by R ５ The definition and preferred embodiment of the embodiment in which R ３ and a group represented by R ３This is the same as when they bond to each other to form a ring.

[0070] Ar ２ and T ２ and may be bonded to each other via a single bond or a divalent linking group to form a ring. ２ represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, Ar ２ and T ２ and may be bonded to each other via a single bond or a divalent linking group to form a ring. ２ represents a group represented by formula (T1), Ar ２ and any of the groups in the formula (T1) may be bonded to each other via a single bond or a divalent linking group to form a ring. ３ Examples of the divalent linking group that can be used to bond the rings to each other include the groups exemplified above. The ring is preferably an aliphatic ring.

[0071] In formula (CT-2), d represents 0 or 1, and is preferably 1.

[0072] In formula (CT-2), d+f is an integer of 1 to 4. That is, when d is 1, f is an integer of 0 to 3, and when d is 0, f is an integer of 1 to 4. d+f is preferably 1 or 2, and more preferably 1. In formula (CT-2), T ２ represents a hydrocarbon group having 1 to 20 carbon atoms which may have a hydrogen atom or a hetero atom, and f is 0.

[0073] The cation represented by formula (CT-1) is preferably a cation represented by formula (CT-11), more preferably a cation represented by formula (CT-12). The cation represented by formula (CT-2) is preferably a cation represented by formula (CT-21).

[0074]

[0075] In formula (CT-11) and formula (CT-21), Ar １１ , Ar １２ , Ar １５ , Ar １６ , and Ar１９ each independently represents an aromatic ring group having 1 to 20 carbon atoms, which may have a substituent. The number of carbon atoms in the aromatic ring group, which may have a substituent, is preferably 4 to 15, more preferably 4 to 12, and even more preferably 5 to 10. The aromatic ring group may be either a monocyclic or polycyclic ring, with a monocyclic ring being preferred. The aromatic ring group may be any of aromatic hydrocarbon groups such as a phenyl group, a naphthyl group, and an anthryl group, and aromatic heterocyclic groups such as a pyrrole ring group, a pyridine ring group, a furan ring group, a thiophene ring group, an indole ring group, a benzofuran ring group, and a benzothiophene ring group, with an aromatic hydrocarbon group being preferred, and a phenyl group being more preferred. Examples of substituents that the aromatic ring group may have include R １ and R ２ Examples of the substituents include those exemplified as the substituents that the aromatic ring group and the aliphatic hydrocarbon group may have, and an alkyl group, an alkoxy group, a halogen atom, or an organometallic group is preferred.

[0076] In formula (CT-11) and formula (CT-21), Ar １３ , Ar １４ , Ar １７ , and Ar １８ are each independently a divalent aromatic ring group which may have a substituent. The aromatic ring may be either a monocyclic or polycyclic ring, with a monocyclic ring being preferred. The divalent aromatic ring group preferably has 5 to 12 ring-member atoms, more preferably 6 to 10. Examples of aromatic rings constituting the divalent aromatic ring group include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, and an anthracene ring, and aromatic heterocycles such as a pyridine ring, a pyridazine ring, a pyridine ring, a furan ring, a thiophene ring, an indole ring, a benzofuran ring, and a benzothiophene ring, with an aromatic hydrocarbon ring being preferred, and a benzene ring being more preferred. Examples of substituents that the aromatic ring group may have include R １ and R ２ Examples of the substituent include those exemplified as the substituent that the aromatic ring group and the aliphatic hydrocarbon group may have, and an alkyl group which may have a halogen atom, an alkoxy group, a halogen atom, or an organometallic group is preferred.

[0077] In formula (CT-11), Ar １１ and Ar １３ , or Ar １１ and Ar １２ may be bonded to each other via a single bond or a divalent linking group to form a ring, and Ar １１ and Ar １２ and are preferably bonded to each other via a single bond to form a ring. １６ and Ar １７ and may be bonded to each other via a single bond or a divalent linking group to form a ring. ３ Examples of the divalent linking group that bonds to each other include the groups exemplified above.

[0078] In formula (CT-11) and formula (CT-21), S １１ and S １２ each independently represents a group represented by any one of the above formulas (S-1) to (S-3), and a group represented by formula (S-1) or a group represented by formula (S-2) is preferred in terms of better effects of the present invention.

[0079] In formula (CT-11) and formula (CT-21), g and h each independently represent 0 or 1, with 0 being preferred.

[0080] When g is 0, Ar １３ and Ar １５ and may be bonded to each other via a single bond or a divalent linking group to form a ring. １３ and Ar １４ may be bonded to each other via a single bond or a divalent linking group to form a ring, and Ar １４ and Ar １５ and may be bonded to each other via a single bond or a divalent linking group to form a ring. １７ and Ar １９ and may be bonded to each other via a single bond or a divalent linking group to form a ring. １７ and Ar １８ may be bonded to each other via a single bond or a divalent linking group to form a ring, and Ar １８ and Ar １９and may be bonded to each other via a single bond or a divalent linking group to form a ring. ３ Examples of the divalent linking group that bonds to each other include the groups exemplified above.

[0081] In formula (CT-12), Ar １１ , Ar １２ , Ar １３ , S １１ , S １２ and g are the same as the respective groups in formula (CT-11).

[0082] Specific examples of the cation X include, but are not limited to, cations having the following structures:

[0083]

[0084] (Cation Y) Cation Y is a cation obtained by changing the structure of cation X due to the action of an acid. An onium base consisting of cation Y and an anionic group (hereinafter also referred to as "onium base Y") generates an acid when irradiated with light having a wavelength of 200 to 450 nm. Due to the above-mentioned properties, an acid may be generated from the onium base Y by exposure in step 3 described below, and the acid may multiply. The onium base Y preferably generates an acid when irradiated with light having a wavelength of 250 to 400 nm. More specifically, it preferably generates an acid when irradiated with light having at least one wavelength selected from 280 nm, 365 nm, and 395 nm.

[0085] The molar absorption coefficient of the bromide salt of cation Y (a salt composed of cation Y and bromide ion) at a wavelength of 280 nm, 365 nm, or 395 nm is 500 L mol －１ ・cm －１ More than 1,000 L / mol is preferable. －１ ・cm －１ More preferably, 2,000 L / mol or more －１ ・cm －１ More preferably, 3,000 L / mol or more －１ ・cm －１The upper limit of the molar absorption coefficient at the wavelength of 280 nm, 365 nm, or 395 nm is not particularly limited, but is preferably 200,000 L mol －１ ・cm －１ It is preferable that the above-mentioned preferred range is satisfied at at least one of the wavelengths of 280 nm, 365 nm, and 395 nm. In addition, the bromide salt of the cation Y has a long-wavelength absorption (molar absorption coefficient of 100 L mol －１ ・cm －１ The molar absorption coefficient of the bromide salt of cation Y is preferably 700 nm or less, more preferably 600 nm or less, and even more preferably 550 nm or less. The molar absorption coefficient of the bromide salt of cation Y is measured by the following method. 12.5 mg of the bromide salt of cation Y is precisely weighed and placed in a 100 mL volumetric flask. Acetonitrile is added to the bromide salt to completely dissolve it. 2 mL of this solution is taken with a volumetric pipette and made up to a volume of 25 mL in a volumetric flask. This is used as the measurement sample. The measurement sample is placed in a 5 mL quartz glass cell, 1 cm square, and the absorbance is measured in air to calculate the molar absorption coefficient. Examples of measurement devices include an ultraviolet-visible-near-infrared spectrophotometer (UH4150, manufactured by Hitachi High-Tech Corporation).

[0086] Cation Y preferably has a multiple bond as a structure resulting from a structural change of cation X due to the action of an acid. Suitable embodiments of the multiple bond are as described above. In cation Y, the multiple bond is preferably not contained in a ring structure or is contained in an aliphatic ring. In other words, it is preferable that the multiple bond does not constitute part of an aromatic ring. Cation Y preferably has a structure resulting from a structural change of cation X due to the action of an acid, in which the groups represented by formulas (S-1) to (S-3) contained in cation X have undergone structural change, and more preferably has groups represented by formulas (S-1') to (S-3') described above. Among these, cation Y is preferably a cation having a structure resulting from a structural change of the groups represented by formulas (S-1) to (S-3) of the cation represented by formula (CT-1) or formula (CT-2) described above, in which the groups represented by formulas (S-1') to (S-3') have undergone structural change.

[0087] (Repeating Unit Represented by Formula (UA-1)) The repeating unit U1 is preferably a repeating unit represented by formula (UA-1).

[0088]

[0089] In formula (UA-1), R ａ１ ~R ａ３ each independently represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, or an alkoxycarbonyl group. The alkyl group may be linear, branched, or cyclic, and is preferably linear or branched. The alkyl group preferably has 1 to 6 carbon atoms, more preferably 1 to 3, and even more preferably 1. The alkoxycarbonyl group preferably has 2 to 7 carbon atoms, more preferably 2 to 4, and even more preferably 2 to 3. R ａ１ is preferably a hydrogen atom, an alkyl group, or a halogen atom. ａ２ and R ａ３ is preferably a hydrogen atom.

[0090] L ａ１ represents a single bond or a divalent linking group. Examples of the divalent linking group include —O—, —CO—, —NR Ｎ -, -SO ２ -, a divalent aliphatic hydrocarbon group which may have a substituent, a divalent aromatic ring group which may have a substituent, and a group formed by combining these. Ｎrepresents a hydrogen atom or an alkyl group. Examples of the divalent aliphatic hydrocarbon group include an alkylene group, an alkenylene group, and an alkynylene group, with an alkylene group being preferred. The divalent aliphatic hydrocarbon group may be linear, branched, or cyclic. The divalent aliphatic hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 2 to 15 carbon atoms. The divalent aromatic ring group may be either a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group, with a divalent aromatic hydrocarbon group being preferred. The aromatic ring group may be either a monocyclic or polycyclic group, with a monocyclic group being preferred. Examples of substituents that the aliphatic hydrocarbon group and aromatic ring group may have include a hydrocarbon group having 1 to 20 carbon atoms, which may have a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, and a halogen atom.

[0091] As the divalent linking group, from the viewpoint of the above-mentioned pKa, ａ１ -L ａ２ -L ａ３ -* ａ２ A group represented by the following formula is preferred. ａ１ indicates the bonding position with the main chain. ａ２ A － represents the bonding position with ａ２ represents a single bond, —O—, —COO—, or —CONR Ｎ L represents an alkylene group, an arylene group, or a group formed by combining these. The alkylene group may be linear, branched, or cyclic. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 2 to 6 carbon atoms. The arylene group is preferably a naphthylene group or a phenylene group, and more preferably a phenylene group. ａ３represents an alkylene group having a substituent selected from a fluorine atom and a perfluoroalkyl group, or an arylene group having a substituent selected from a fluorine atom and a perfluoroalkyl group. The alkylene group may be linear, branched, or cyclic, with linear being preferred. The alkylene group preferably has 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms. The arylene group may be monocyclic or polycyclic, with monocyclic being preferred. The arylene group is preferably a naphthylene group or a phenylene group, more preferably a phenylene group. "Having a substituent selected from a fluorine atom and a perfluoroalkyl group" means that some or all of the hydrogen atoms of the alkylene group and arylene group are substituted with a substituent selected from a fluorine atom and a perfluoroalkyl group. In terms of better effects of the present invention, it is more preferred that all of the hydrogen atoms are substituted with the substituent. The perfluoroalkyl group preferably has 1 to 3 carbon atoms. Among these, a perfluoromethyl group is preferred as the perfluoroalkyl group.

[0092] In formula (UA-1), A － represents an anionic group, C ＋ represents a cation. － and C ＋ The definition and preferred embodiment of A in the above formula (1) － and C ＋ is the same as

[0093] Specific examples of the repeating unit U1 include, but are not limited to, the repeating units shown below.

[0094]

[0095] The repeating unit U1 may be used alone or in combination of two or more. The content of the repeating unit U1 is preferably 1 to 100 mol %, more preferably 5 to 100 mol %, and even more preferably 10 to 100 mol %, based on the total repeating units of the specific resin.

[0096] The specific resin may have a repeating unit other than the repeating unit U1. Examples of repeating units other than the repeating unit U1 include a repeating unit M1 having an organometallic structure, which will be described later, and a repeating unit Q1 having acid diffusion controllability, which will be described later. In terms of achieving better effects of the present invention, the specific resin preferably contains the repeating unit U1 and the repeating unit M1. The total content of the repeating unit U1 and the repeating unit M1 is preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more, based on the repeating units of the specific resin. The upper limit may be 100 mol%.

[0097] Further, other repeating units other than the above-described repeating units may be contained within a range that does not impair the effects of the present invention. Examples of other repeating units include repeating units having an acid-decomposable group described in paragraphs

[0053] to

[0057] of WO 2020 / 158467, repeating units having an acid group described in paragraphs

[0081] to

[0086] of WO 2020 / 158467, repeating units having a lactone structure or a sultone structure described in paragraphs

[0094] to

[0107] of WO 2016 / 136354, repeating units having a carbonate structure described in paragraphs

[0106] to

[0108] of WO 2019 / 054311, repeating units having a fluorine atom or an iodine atom, and repeating units having neither an acid-decomposable group nor a polar group.

[0098] The specific resin can be synthesized according to a conventional method (e.g., radical polymerization). The weight average molecular weight (Mw) of the specific resin is preferably 2,000 or more, more preferably 3,000 or more, and even more preferably 4,000 or more. The upper limit is, for example, preferably 12,000 or less, more preferably 10,000 or less, and even more preferably 8,000 or less. The polydispersity index (PDI, Mw / Mn) of the specific resin is not particularly limited, but is preferably 2.0 or less, more preferably 1.8 or less, and even more preferably 1.6 or less. The lower limit is 1.0 or more.

[0099] The specific resin may be used alone or in combination of two or more. The content of the specific resin is preferably 40% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more, based on the total solid content of the photosensitive composition. The upper limit may be 100% by mass.

[0100] [Organometallic Structure and Organometallic Compound] In the photosensitive composition, the specific resin has an organometallic structure, or the photosensitive composition has an organometallic compound different from the specific resin. The organometallic structure is a structure including an organometallic bond in which a metal is bonded to an organic group. The organometallic compound has an organometallic bond and is a compound different from the specific resin described above. In terms of achieving better effects of the present invention, it is preferable that the specific resin has an organometallic structure. Note that the specific resin may have an organometallic structure, and the photosensitive composition may further include an organometallic compound different from the specific resin.

[0101] The metal atoms in the organometallic structure and organometallic compound are not particularly limited, and examples thereof include B, Al, Si, As, Ti, Zr, Mo, Se, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, and At. In terms of the effects of the present invention being more excellent, the metal atom is preferably at least one selected from the group consisting of Sn, Bi, Ge, Si, As, Se, Sb, Te, Pb, and Po, more preferably at least one selected from the group consisting of Sn, Bi, and Ge, and even more preferably at least one selected from the group consisting of Sn and Bi. In this specification, metalloid atoms such as Si and Ge are metal atoms.

[0102] (Partial Structure Represented by Formula (2)) In view of achieving superior effects of the present invention, it is preferable that the organometallic structure and the organometallic compound have a partial structure represented by formula (2). In other words, when the specific resin contains an organometallic structure, it is preferable that the specific resin has a partial structure represented by formula (2), and when the photosensitive composition contains an organometallic compound, it is preferable that the organometallic compound has a partial structure represented by formula (2). The partial structure represented by formula (2) is preferable in that the bond between M-Ar is decomposed by the action of an acid derived from the onium salt group represented by formula (1), forming a bond (A-M) between the anionic group and the metal atom in formula (1), and thus polarity contrast is likely to be generated.

[0103] Formula (2) (R) ｎ -M-Ar

[0104] In formula (2), M represents a metal atom. Preferred embodiments of the metal atom represented by M are as described above.

[0105] In formula (2), Ar represents an aromatic ring. Examples of the aromatic ring include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, and an anthracene ring, and aromatic heterocycles such as a pyridine ring, a pyridazine ring, a pyridine ring, a furan ring, a thiophene ring, an indole ring, a benzofuran ring, and a benzothiophene ring, with an aromatic hydrocarbon ring being preferred, and a benzene ring being more preferred. The aromatic ring group preferably has 5 to 12 ring-member atoms, more preferably 6 to 10. The aromatic ring may be either a monocyclic or polycyclic ring, with a monocyclic ring being preferred. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring, with a benzene ring being preferred.

[0106] In formula (2), n represents the valence of the metal atom minus 1. The valence of the metal atom varies depending on the metal atom, but n is often 1 to 6, and more often 2 to 4.

[0107] In formula (2), each R independently represents a substituent. The substituent is preferably a monovalent organic group. Examples of the monovalent organic group include an aliphatic hydrocarbon group (preferably having 1 to 6 carbon atoms), an aromatic ring group (preferably having 5 to 12 carbon atoms), an alkoxy group (preferably having 1 to 6 carbon atoms), an aryloxy group (preferably having 5 to 12 carbon atoms), an alkylcarbonyloxy group (preferably having 2 to 7 carbon atoms), an arylcarbonyloxy group (preferably having 6 to 13 carbon atoms), an alkylthio group (preferably having 1 to 6 carbon atoms), and an arylthio group (preferably having 5 to 12 carbon atoms). The above group may have the above group as a substituent, or may have a hydroxy group or a halogen atom as a substituent. The monovalent organic group is preferably an aliphatic hydrocarbon group which may have a substituent, an alkylcarbonyloxy group which may have a substituent, or an arylcarbonyloxy group which may have a substituent.

[0108] Hereinafter, an embodiment in which the specific resin has an organometallic structure and an embodiment in which the photosensitive composition contains an organometallic compound will be described in detail.

[0109] <Aspects in which the specific resin has an organometallic structure> When the specific resin has an organometallic structure, the specific resin preferably has a repeating unit containing an organometallic structure. When the specific resin has an organometallic structure, the repeating unit U1 may contain an organometallic structure, or the specific resin may have a repeating unit containing an organometallic structure (hereinafter also referred to as "repeating unit M1") that is different from the repeating unit U1. Note that the repeating unit U1 may contain an organometallic structure, and the specific resin may have the repeating unit M1.

[0110] The repeating unit U1 may include an organometallic structure in any suitable form. For example, the repeating unit U1 may include an organometallic structure as part of the linking group between the main chain of the resin and the onium base represented by formula (1). The cation X in formula (1) may include an organometallic structure, and it is preferred that the cation X includes an organometallic structure. Examples of the form in which the cation X includes an organometallic structure include a form in which the cation represented by formula (CT-1) or formula (CT-2) includes an organometallic group. In particular, the R １ ~R ５ , T １ , R Ｔ１ , and R Ｔ２ It is preferable that at least one of R in formula (CT-1) and R in formula (CT-2) has an organometallic group. １ ~R ５ , T １ , R Ｔ１ , and R Ｔ２ It is more preferable that at least one of them contains a partial structure represented by formula (2).

[0111] (Repeating unit M1) The repeating unit M1 is a repeating unit different from the repeating unit U1, and is not particularly limited as long as it is a repeating unit containing an organometallic structure, but is preferably a repeating unit containing the partial structure represented by the above formula (2). In particular, as the repeating unit M1, a repeating unit represented by formula (UM-1) is more preferable.

[0112]

[0113] In formula (UM-1), R ａ１ ~R ａ３ are the same as the respective groups in formula (UA-1), M, R, and n are the same as the respective groups in formula (2).

[0114] In formula (UM-1), L ｍ１ is a single bond or a divalent linking group. Examples of the divalent linking group include L ａ１ Examples of the divalent linking group represented by the formula: ｍ１is preferably a single bond, -COO-, -arylene group -O-, or -arylene group -COO-, and more preferably a single bond.

[0115] Ar ｍ１ represents a divalent aromatic ring group which may have a substituent. The aromatic ring constituting the divalent aromatic ring group is preferably the aromatic ring represented by Ar in formula (2). Examples of substituents which the aromatic ring group may have include alkyl groups (e.g., having 1 to 15 carbon atoms), aryl groups (e.g., having 6 to 14 carbon atoms), alkoxy groups (e.g., having 1 to 15 carbon atoms), aryloxy groups (e.g., having 6 to 14 carbon atoms), acyl groups (e.g., having 2 to 15 carbon atoms), alkylthio groups (e.g., having 1 to 15 carbon atoms), arylthio groups (e.g., having 6 to 14 carbon atoms), carboxy groups, hydroxy groups, mercapto groups, amino groups, nitro groups, phosphino groups, halogen atoms, and cyano groups. The substituents may further have a substituent if possible. The substituent is preferably a halogen atom or an alkyl group having a halogen atom, more preferably a fluorine atom or a perfluoroalkyl group, and even more preferably a fluorine atom. When the aromatic ring has a substituent, the number of substituents is preferably 1 to 8, more preferably 1 to 4. Ar ｍ１ When has a halogen atom or an alkyl group having a halogen atom as a substituent, it is also preferable that all of the substituents on the divalent aromatic ring group are substituted with the above-mentioned substituents.

[0116] Examples of the monomer that provides the repeating unit M1 include, but are not limited to, the repeating units shown below.

[0117]

[0118] The repeating unit M1 may be used alone or in combination of two or more. The content of the repeating unit M1 is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more, based on the total repeating units of the specific resin. The upper limit is less than 100 mol%, preferably 99 mol% or less, more preferably 95 mol% or less, and even more preferably 90 mol% or less.

[0119] <Embodiment in which the photosensitive composition contains an organometallic compound> The organometallic compound may be either a low molecular weight compound or a high molecular weight compound. When the organometallic compound is a low molecular weight compound, the molecular weight is preferably 3,000 or less, more preferably 2,000 or less, and even more preferably 1,000 or less. There is no particular lower limit, but a molecular weight of 100 or more is preferred. Examples of organometallic compounds that are high molecular weight compounds include resins that do not have a repeating unit U1 but have a repeating unit M1.

[0120] As the organometallic compound which is a low molecular weight compound, a low molecular weight compound having a partial structure represented by formula (2) is preferred, and a compound represented by formula (M-1) is more preferred.

[0121] Formula (M-1) (R) ｎ -M-Ar ｍ２ - (R ｍ１ ) ｎ２

[0122] In formula (M-1), R, n, and M are the same as the respective groups in formula (2) above. ｍ２ represents an aromatic ring group having a valence of n2+1. The definition and preferred embodiments of the aromatic ring constituting the aromatic ring group are the same as those of the aromatic ring represented by Ar in formula (2). ｍ１ represents a substituent. In formula (UM-1), Ar ｍ１ n2 represents an integer of 0 or more, preferably an integer of 0 to 8, and more preferably an integer of 0 to 4.

[0123] The organometallic compounds may be used singly or in combination of two or more. When the photosensitive composition contains an organometallic compound, the content of the organometallic compound is preferably 10 to 80 mass %, more preferably 30 to 70 mass %, based on the total solid content of the photosensitive composition.

[0124] [Acid Diffusion Controller and Repeating Unit Having Acid Diffusion Controlling Properties] The photosensitive composition preferably satisfies at least one of the following requirements Q1 and Q2, and more preferably satisfies requirement Q1. Requirement Q1: The photosensitive composition contains an acid diffusion controller that is different from the specific resin. Requirement Q2: The specific resin has a repeating unit that has acid diffusion controlling properties. Below, aspects that satisfy each requirement will be described in detail.

[0125] <Requirement Q1> The acid diffusion controller traps the acid generated upon exposure and acts as a quencher to suppress reactions in unexposed areas caused by excess generated acid. Examples of the generated acid include acids derived from onium bases represented by the above-mentioned formula (1) and acids derived from other photoacid generators. The type of acid diffusion controller is not particularly limited, and examples include basic compounds (DA), compounds (DB) whose basicity is reduced or eliminated upon irradiation with actinic rays or radiation, low-molecular-weight compounds (DC) having a group that leaves under the action of an acid, and onium salt compounds (DD) that generate an acid that is weaker than the generated acid. The acid diffusion controller may be either a low-molecular-weight compound or a high-molecular-weight compound. When the acid diffusion controller is a low-molecular-weight compound, the molecular weight is preferably 3,000 or less, more preferably 2,000 or less, and even more preferably 1,000 or less. The lower limit is not particularly limited, but a molecular weight of 100 or more is preferred. An embodiment in which the acid diffusion controller is a polymer compound includes a resin in which the acid diffusion controller is incorporated into a part of the resin, and specifically includes a resin that does not have the repeating unit U1 described above but has a repeating unit having acid diffusion controllability (preferably the repeating unit Q1 described below). Note that an acid diffusion controller in the form of a low molecular weight compound and an acid diffusion controller in the form of a polymer compound may be used in combination.

[0126] Specific examples of the basic compound (DA) include those described in paragraphs

[0132] to

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

[0137] to

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

[0156] to

[0163] of WO 2020 / 066824. Specific examples of the onium salt compound (DD) that generates an acid that is weaker than the generated acid include those described in paragraphs

[0164] of WO 2020 / 066824 and paragraphs

[0305] to

[0314] of WO 2020 / 158337.

[0127] In addition to the above, for example, known compounds disclosed in paragraphs

[0627] to

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

[0095] to

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

[0403] to

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

[0259] to

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

[0128] When the acid diffusion controller is an onium salt compound (DD) that generates an acid that is weaker than the generated acid, the acid dissociation constant of the generated acid is preferably 20 or less, more preferably 15 or less. The lower limit of the acid dissociation constant is preferably greater than -1.0, more preferably 0 or more, and even more preferably 0.5 or more. The onium salt compound is preferably a sulfonium salt compound or an iodonium salt compound. The cation in the onium salt compound is preferably a sulfonium cation or an iodonium cation. The cation may be the above-mentioned cation X or cation Y. The anion in the onium salt compound is preferably a carboxylate anion.

[0129] The acid diffusion controller may be used alone or in combination of two or more. When the photosensitive composition contains an acid diffusion controller, the content of the acid diffusion controller is preferably 0.1 to 20 mass %, more preferably 0.1 to 15 mass %, and still more preferably 1.0 to 15 mass %, based on the total solid content of the photosensitive composition.

[0130] <Requirement Q2> When requirement Q2 is satisfied, the specific resin preferably has a repeating unit (hereinafter also referred to as "repeating unit Q1") that has acid diffusion control properties and is different from the repeating unit U1 and the repeating unit M1 described above.

[0131] The repeating unit Q1 preferably has an acid diffusion control group that has the same effect as the acid diffusion controller described above. Specific examples of the acid diffusion control group include a basic group (DA'), a group (DB') whose basicity decreases or disappears upon irradiation with actinic rays or radiation, a group (DC') that is cleaved by the action of an acid, and an onium base (DD') that generates an acid that is weaker than the generated acid described above. Examples of the acid diffusion control group include the structures described in paragraphs

[0165] to

[0170] of JP 2017-167371 A. Groups obtained by removing one or more hydrogen atoms from the acid diffusion controller described above can also be used. When the repeating unit Q1 has an onium base (DD') that generates an acid that is weaker than the generated acid described above, the acid dissociation constant of the generated acid generated from the monomer that gives the repeating unit having the onium base (DD') is preferably 20 or less, more preferably 15 or less. The lower limit of the acid dissociation constant is preferably greater than -1.0, more preferably equal to or greater than 0, and even more preferably equal to or greater than 0.5. The onium base is preferably a sulfonium base or an iodonium base. The cation in the onium base is preferably a sulfonium cation or an iodonium cation. The cation may be the above-mentioned cation X or cation Y. The anion in the onium base is preferably a carboxylate anion.

[0132] The repeating unit Q1 may be used singly or in combination of two or more. When the resin A1 has the repeating unit Q1, the content of the repeating unit Q1 is preferably 0.1 to 20 mol %, more preferably 0.1 to 15 mol %, and still more preferably 1.0 to 15 mol %, based on the total repeating units of the resin A1.

[0133] [Photoacid Generator] The photosensitive composition may contain a photoacid generator. When the onium salt X is a group that does not generate an acid when irradiated with light having a wavelength of less than 200 nm, the photosensitive composition preferably contains a photoacid generator that generates an acid when irradiated with light having a wavelength of less than 200 nm. In terms of achieving better effects of the present invention, it is also preferable that the photosensitive composition does not contain a photoacid generator different from the specific resin.

[0134] The photoacid generator may be in the form of a low molecular weight compound or a polymeric compound. When the photoacid generator is in the form of a low molecular weight compound, the molecular weight of the photoacid generator is preferably 5,000 or less, more preferably 4,000 or less, and even more preferably 3,000 or less. There is no particular lower limit, but a molecular weight of 100 or more is preferred. An embodiment in which the photoacid generator is a polymeric compound includes a form in which the photoacid generator is incorporated into a part of a resin, specifically a resin covalently bonded to the photoacid generator. A photoacid generator in the form of a polymeric compound and a photoacid generator in the form of a polymer may be used in combination. The resin is preferably a resin different from the specific resin. The photoacid generator is preferably an onium salt compound, and more preferably a sulfonium salt compound or an iodonium salt compound. The cation of the onium salt compound serving as the photoacid generator may be the cation X or cation Y described above.

[0135] Examples of photoacid generators that can be used include 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, and the compounds exemplified in paragraphs

[0023] to

[0078] of WO 2020 / 158313, the contents of which are incorporated herein by reference.

[0136] The photoacid generator may be used singly or in combination of two or more. When the photosensitive composition contains a photoacid generator, the content of the photoacid generator is preferably 0.1 to 50 mass %, more preferably 0.1 to 40 mass %, and still more preferably 1.0 to 30 mass %, based on the total solid content of the photosensitive composition.

[0137] [Other Components] The photosensitive composition may contain other components in addition to the components described above.

[0138] <Surfactant> The photosensitive composition may contain a surfactant. The surfactant is preferably a fluorine-based and / or silicone-based surfactant. Examples of the fluorine-based and / or silicone-based surfactant include the surfactants disclosed in paragraphs

[0218] and

[0219] of WO 2018 / 193954.

[0139] The surfactant may be used alone or in combination of two or more. When the photosensitive composition contains a surfactant, the content of the surfactant is preferably 0.0001 to 2 mass %, more preferably 0.0005 to 1 mass %, based on the total solid content of the photosensitive composition.

[0140] <Hydrophobic Resin> The photosensitive composition may contain a hydrophobic resin as a resin different from the specific resin described above. The hydrophobic resin is preferably designed to be unevenly distributed on the surface of the resist film formed by the photosensitive composition, but unlike surfactants, it does not necessarily have to have a hydrophilic group in the molecule and does not necessarily have to contribute to uniform mixing of polar and non-polar substances. The effects of adding a hydrophobic resin include controlling the static and dynamic contact angles of the resist film surface with water and suppressing outgassing.

[0141] The hydrophobic resin contains fluorine atoms, silicon atoms, and CH atoms contained in the side chain portion of the resin in order to be unevenly distributed on the surface layer of the film. ３It is preferable to have one or more of the partial structures, and more preferably two or more. The hydrophobic resin preferably has a hydrocarbon group having 5 or more carbon atoms. These groups may be present in the main chain of the resin or may be substituted on a side chain. Examples of hydrophobic resins include the compounds described in paragraphs

[0275] to

[0279] of WO 2020 / 004306.

[0142] The hydrophobic resin may be used singly or in combination of two or more. When the photosensitive composition contains a hydrophobic resin, the content of the hydrophobic resin is preferably 0.01 to 20.0 mass %, more preferably 0.1 to 15.0 mass %, based on the total solid content of the photosensitive composition.

[0143] <Solvent> The photosensitive composition may contain a solvent. The solvent preferably contains (M1) propylene glycol monoalkyl ether carboxylate and (M2) at least one selected from the group consisting of propylene glycol monoalkyl ether, lactate ester, acetate ester, alkoxypropionate ester, chain ketone, cyclic ketone, lactone (e.g., γ-butyrolactone), and alkylene carbonate. The solvent may further contain a component other than components (M1) and (M2).

[0144] The use of the above-mentioned solvent in combination with the specific resin is preferable in that it improves the coatability of the photosensitive composition and reduces the number of development defects in the pattern. The above-mentioned solvent has a good balance of the solubility, boiling point, and viscosity of the specific resin, and therefore can suppress unevenness in the film thickness of the resist film and the occurrence of precipitates during spin coating. Details of component (M1) and component (M2) are as described in paragraphs

[0218] to

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

[0145] 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.

[0146] The content of the solvent is preferably determined so that the solid content concentration is 0.5 to 30% by mass, more preferably 1 to 20% by mass, from the viewpoint of the coatability of the photosensitive composition.

[0147] The photosensitive composition may contain additives other than those described above, provided that the effects of the present invention are not impaired. Examples of such additives include sensitizers, dissolution-inhibiting compounds, dyes, plasticizers, and compounds that promote solubility in the developer (e.g., phenolic compounds having a molecular weight of 1,000 or less, and alicyclic or aliphatic compounds containing a carboxylic acid group).

[0148] [Resist Film] The resist film of the present invention is a film formed using the photosensitive composition of the present invention. The resist film may be a coating film of the photosensitive composition, or may be a film formed by drying a coating film of the photosensitive composition. The thickness of the resist film is not particularly limited, but is preferably 10 to 120 nm from the viewpoint of being able to form a fine pattern with higher precision. In particular, when pattern exposure is performed using EUV or EB, the thickness of the resist film is more preferably 10 to 90 nm, and even more preferably 15 to 70 nm.

[0149] [Pattern Forming Method] The pattern forming method of the present invention (hereinafter also referred to as "this pattern forming method") is not particularly limited as long as it is a method of forming a pattern using the photosensitive composition of the present invention, but preferably includes the following steps: Step 1: A step of forming a resist film on a substrate using the photosensitive composition Step 2: A step of irradiating the resist film with light having a wavelength of less than 200 nm to perform pattern exposure Step 3: A step of irradiating the pattern-exposed resist film with light having a wavelength of 200 to 450 nm to perform exposure Step 4: A step of developing the exposed resist film with a developer to form a pattern Each step will be described in detail below.

[0150] [Step 1: Resist Film Forming Step] Step 1 is a step of forming a resist film on a substrate using a photosensitive composition. The definition and preferred embodiments of the photosensitive composition are as described above.

[0151] A method for forming a resist film on a substrate using a photosensitive composition includes, for example, applying the photosensitive composition to the substrate. It is preferable to filter the photosensitive composition as needed before application. 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.

[0152] The photosensitive composition can be applied to a substrate (e.g., silicon, silicon dioxide coated) such as those used in the manufacture of integrated circuit elements by a suitable 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. If necessary, various undercoating films (inorganic film, organic film, anti-reflective film) may be formed under the resist film.

[0153] After coating the photosensitive composition, the substrate may be dried to form a resist film. Drying methods include, for example, heating. Heating can be performed using a means provided in a typical 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.

[0154] The thickness of the resist film is not particularly limited, but from the viewpoint of forming a finer pattern with higher precision, the thickness is preferably 10 to 120 nm, more preferably 10 to 90 nm, and even more preferably 15 to 70 nm.

[0155] A top coat may be formed on the upper layer of 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 upper layer of the resist film. The top coat can be formed by a conventionally known method, for example, based on the description in paragraphs

[0072] to

[0082] of JP 2014-059543 A. A top coat containing a basic compound, such as that described in JP 2013-061648 A, is preferred. Specific examples of basic compounds that may be contained in the top coat include basic compounds that may be contained in the photosensitive 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 mercapto group, a carbonyl bond, and an ester bond.

[0156] [Step 2: Patternwise Exposure Step] Step 2 is a step of irradiating the resist film with light having a wavelength of less than 200 nm to perform patternwise exposure. It is preferred that step 2 generates an acid in the exposed region of the resist film, and that the cation X undergoes a structural change due to the action of the acid to generate a cation Y. The acid is preferably an acid derived from an onium base X. In such a case, it is preferred that the exposure decomposes a portion of the cation X to generate an acid, and that some or all of the remaining cations X undergo a structural change to form a cation Y. It is preferred that the exposure dose in step 2 is adjusted so that only a portion of the cation X decomposes.

[0157] The exposure method includes irradiating the formed resist film with actinic rays or radiation having a wavelength of less than 200 nm through a predetermined mask. The exposure light containing light having a wavelength of less than 200 nm is preferably far ultraviolet light having a wavelength of less than 200 nm, and specifically, for example, ArF excimer laser (193 nm), F ２ Examples of actinic rays or radiation include excimer laser (157 nm), EUV (13 nm), X-rays, and electron beams (EB). Of these, EUV or electron beams are preferred as actinic rays or radiation.

[0158] [Step 3: Exposure Step] Step 3 is a step of exposing the pattern-exposed resist film by irradiating it with light having a wavelength of 200 to 450 nm. In Step 3, an acid is preferably generated from the onium base Y generated in Step 2. This allows the acid to grow in a chemically amplified manner in the exposed region of Step 2. Furthermore, a reaction between the acid and the organometallic structure or organometallic compound described above may proceed, resulting in a change in the polarity of the specific resin. As a result, a dissolution contrast of the resist film in the developer in Step 4 is created, allowing a pattern to be formed.

[0159] In terms of exposure efficiency, step 3 is preferably flood exposure (full surface exposure). The exposure light in step 3 is light having a wavelength of 200 to 450 nm, and specifically, light having at least one wavelength selected from wavelengths of 280 nm, 365 nm, and 395 nm is preferred. The exposure light preferably has a wavelength of 280 nm or more, more preferably 320 nm or more. Examples of the exposure light include infrared light, visible light, and near-ultraviolet light, with near-ultraviolet light being preferred. The exposure dose is preferably 0.1 to 5000 mJ, more preferably 0.1 to 3000 mJ.

[0160] The exposure in the above-described steps 2 and 3 is preferably carried out in air, a reduced pressure atmosphere, or an inert atmosphere, and more preferably in a reduced pressure atmosphere or an inert atmosphere containing nitrogen or argon.

[0161] [Step 4: Development Step] Step 4 is a step of developing the exposed resist film using a developer to form a pattern. The developer may be either an organic solvent-based developer (a developer containing an organic solvent) or an alkaline developer, with an organic solvent-based developer being preferred in terms of achieving better effects of the present invention. By using an organic solvent-based developer as the developer, the resist film in the exposed areas can be removed. That is, a positive pattern can be formed using the photosensitive composition. By using an alkaline developer as the developer, the resist film in the unexposed areas can be removed. That is, a negative pattern can be formed using the photosensitive composition.

[0162] Examples of development methods include a method in which a substrate is immersed in a tank filled with a developer for a certain period of time (dip method), a method in which a developer is piled up on the surface of a substrate by surface tension and left to stand for a certain period of time for development (puddle method), a method in which a developer is sprayed onto the surface of the substrate (spray method), and a method in which a developer is continuously dispensed onto a substrate rotating at a constant speed while a developer dispense nozzle is scanned at a constant speed (dynamic dispense method). Furthermore, after the development step, a step of stopping development while replacing the solvent with another solvent may be carried out. The development time is not particularly limited as long as it is long enough to sufficiently dissolve the resin in the unexposed areas, and is preferably 10 to 300 seconds, more preferably 20 to 120 seconds. The temperature of the developer is preferably 0 to 50°C, more preferably 15 to 35°C.

[0163] The organic solvent-based developer preferably contains 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, and more preferably contains at least one organic solvent selected from the group consisting of ketone-based solvents, ester-based solvents, and hydrocarbon-based solvents.

[0164] The ClogP value of the organic solvent contained in the organic solvent-based developer is not particularly limited, but is preferably 0.00 or more, and more preferably 1.00 or more. When two or more organic solvents are contained, the ClogP value of the mixed solvent thereof preferably falls within the above range.

[0165] Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 2-heptanone (methyl amyl ketone), 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, isophorone, and propylene carbonate.

[0166] Examples of ester-based solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, pentyl acetate, isopentyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl-3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, butyl butanoate, methyl 2-hydroxyisobutyrate, isoamyl acetate, isobutyl isobutyrate, and butyl propionate.

[0167] As the alcohol-based solvent, the amide-based solvent, the ether-based solvent, and the hydrocarbon-based solvent, for example, the solvents disclosed in paragraphs

[0715] to

[0718] of the specification of U.S. Patent Application Publication No. 2016 / 0070167 can be used.

[0168] The above solvents may be mixed in combination, or may be mixed with a solvent other than those listed above or with 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 solvent-based developer is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and particularly preferably 95 to 100% by mass, based on the total amount of the developer.

[0169] In order to achieve more excellent effects of the present invention, it is preferable that the organic solvent-based developer contains a first organic solvent and a second organic solvent. In order to achieve more excellent effects of the present invention, it is more preferable that the boiling point of the first organic solvent is higher than the boiling point of the second organic solvent and that the ClogP value of the first organic solvent is higher than the ClogP value of the second organic solvent. In order to achieve more excellent effects of the present invention, it is preferable that the evaporation rate of the second organic solvent is faster than the evaporation rate of the first organic solvent. In particular, the greater the difference in evaporation rate between the second organic solvent and the first organic solvent, the more preferable. One indicator of the evaporation rate of an organic solvent is its vapor pressure at 20°C, and it is preferable that the vapor pressure of the second organic solvent is higher than that of the first organic solvent. Specifically, the difference in vapor pressure between the second organic solvent and the first organic solvent is preferably 0.2 kPa or more, more preferably 0.5 kPa or more, even more preferably 0.8 kPa or more, and particularly preferably 1.0 kPa or more. Although the mechanism of action of the organic solvent-based developer having the above composition is not clear, it is presumed that the use of the organic solvent-based developer having the above composition suppresses swelling of the resist pattern due to the developer.

[0170] In order to obtain better effects of the present invention, the mass ratio of the content of the first organic solvent to the content of the second organic solvent is preferably 10 / 90 to 50 / 50, and more preferably 10 / 90 to 30 / 70.

[0171] As the second organic solvent, the ketone solvents or the ester solvents are preferred, more preferably ester solvents, still more preferably ester solvents having 6 or less carbon atoms, and particularly preferably butyl acetate, in terms of the superior effects of the present invention. Furthermore, the first organic solvent is not particularly limited, but is preferably an organic solvent having a ClogP value of 3.00 or more, and more preferably a hydrocarbon solvent (preferably a hydrocarbon solvent having 10 or more carbon atoms, such as undecane).

[0172] Among them, the organic solvent-based developer preferably contains a hydrocarbon solvent and an ester solvent having 6 or less carbon atoms, and the mass ratio of the hydrocarbon solvent to the ester solvent having 6 or less carbon atoms is preferably 10 / 90 to 50 / 50, more preferably 10 / 90 to 30 / 70, and even more preferably 10 / 90 to 25 / 75.

[0173] The alkaline developer is preferably an aqueous alkaline solution containing an alkali. The type of alkaline aqueous solution is not particularly limited, but examples include aqueous alkaline solutions containing a quaternary ammonium salt, such as tetramethylammonium hydroxide, an inorganic alkali, a primary amine, a secondary amine, a tertiary amine, an alcohol amine, or a cyclic amine. Of these, the alkaline developer is preferably an aqueous solution of a quaternary ammonium salt, such as tetramethylammonium hydroxide (TMAH). Appropriate amounts of alcohols, surfactants, and the like may be added to the alkaline developer. The alkaline concentration of the alkaline developer is usually preferably 0.1 to 20% by mass. The pH of the alkaline developer is usually preferably 10.0 to 15.0.

[0174] [Step 2-A: Heating Step] The present pattern formation method preferably includes, after step 2 and before step 3, step 2-A (PEB: Post Exposure Bake) of heating the pattern-exposed resist film obtained in step 2. This step promotes the reaction in the exposed region in step 2 (specifically, the structural change from cation X to cation Y due to the action of acid), thereby further enhancing the effects of the present invention.

[0175] The heating temperature is preferably 30 to 150°C, more preferably 50 to 140°C, and even more preferably 60 to 120°C. The heating time is preferably 5 to 1000 seconds, more preferably 10 to 180 seconds, and even more preferably 10 to 120 seconds. Heating can be carried out by means provided in a normal exposure machine and / or developing machine, and may also be carried out using a hot plate or the like. The heating step is also preferably carried out in a humidity-controlled environment.

[0176] [Step 3-A: Heating Step] The present pattern formation method also preferably includes, after step 3 and before step 4, step 3-A (PEB) of heating the exposed resist film obtained in step 3. This step promotes the reaction in the exposed region in step 2 (specifically, the reaction between the acid derived from the onium base Y and the organometallic structure or the organometallic compound), thereby further improving the effects of the present invention.

[0177] The heating temperature is preferably 30 to 150°C, more preferably 60 to 140°C, and even more preferably 60 to 120°C. The heating time is preferably 5 to 1000 seconds, more preferably 10 to 180 seconds, and even more preferably 10 to 120 seconds. Heating can be carried out by means provided in a normal exposure machine and / or developing machine, and may also be carried out using a hot plate or the like. The heating step is also preferably carried out in a humidity-controlled environment.

[0178] [Step 5: Rinsing Step] The pattern forming method preferably includes, after step 4, step 5 of rinsing the developed resist film obtained in step 4 with a rinse liquid.

[0179] Examples of rinsing methods include the same methods as the developing method in step 4 above (dipping, puddling, spraying, dynamic dispensing, etc.). The processing time is preferably 10 to 300 seconds, more preferably 10 to 120 seconds, still more preferably 10 to 100 seconds, and particularly preferably 10 to 60 seconds. The temperature of the rinse solution is preferably 0 to 50°C, more preferably 15 to 35°C.

[0180] When the developer is an organic solvent-based developer, the rinse liquid is preferably an organic solvent-based rinse liquid. The type and preferred embodiments of the organic solvent contained in the organic solvent-based rinse liquid are the same as those of the organic solvent contained in the organic solvent-based developer described above.

[0181] In terms of achieving better effects of the present invention, the organic solvent-based rinse solution preferably contains a first organic solvent and a second organic solvent, and more preferably the boiling point of the first organic solvent is higher than the boiling point of the second organic solvent and the ClogP value of the first organic solvent is higher than the ClogP value of the second organic solvent.

[0182] In order to obtain better effects of the present invention, the mass ratio of the content of the first organic solvent to the content of the second organic solvent is preferably 10 / 90 to 50 / 50, and more preferably 10 / 90 to 30 / 70.

[0183] The second organic solvent is preferably the ketone solvent or the ester solvent, more preferably an ester solvent, and even more preferably butyl acetate or isoamyl butyrate, in terms of the superior effects of the present invention. The first organic solvent is not particularly limited, but is preferably an organic solvent having a ClogP value of 3.00 or more, and more preferably a hydrocarbon solvent (preferably a hydrocarbon solvent having 10 or more carbon atoms, such as undecane).

[0184] When the developer is an alkaline developer, the rinse liquid is preferably pure water, to which an appropriate amount of surfactant may be added.

[0185] A suitable amount of a surfactant may be added to the rinse solution.

[0186] This pattern formation method may include a heating step (post-bake) after the rinsing step. This step removes the developer and rinsing solution remaining between and inside the pattern. 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 usually performed at 40 to 250°C (preferably 90 to 200°C) for usually 10 seconds to 3 minutes (preferably 30 to 120 seconds).

[0187] [Other Steps] The pattern formation method may further include other steps in addition to those described above.

[0188] <Etching step> 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 4 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 4 as a mask is preferred. The dry etching is preferably oxygen plasma etching.

[0189] <Purification step> The pattern formation method may include a purification step of purifying the photosensitive composition, developer, rinse, and / or other various components (for example, an anti-reflective film-forming composition and a top coat-forming composition) used in the pattern formation method. Examples of various purification methods include filtration using a filter and a method using an adsorbent. Examples of filtration using a filter include the method described in paragraph

[0321] of WO 2020 / 004306.

[0190] The photosensitive composition, developer, and other various components preferably do not contain impurities. Furthermore, the various components preferably do not contain metal components (hereinafter also referred to as "metal impurities") that are not derived from the organometallic structure or organometallic compound described above. Methods for reducing impurities such as metals contained in the 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 lining the inside of the apparatus with Teflon (registered trademark) to perform distillation under conditions that minimize contamination.

[0191] In addition to filter filtration, impurities may be removed using an adsorbent, or a combination of filter filtration and an adsorbent may be used. Known adsorbents can be used as the adsorbent, including inorganic adsorbents such as silica gel and zeolite, and organic adsorbents such as activated carbon. In order to reduce impurities such as metals contained in the various materials, it is necessary to prevent the incorporation of metal impurities during the manufacturing process. Whether metal impurities have been sufficiently removed from the manufacturing equipment can be confirmed by measuring the content of metal components contained in the cleaning solution used to clean the manufacturing equipment. The content of metal components contained in the used cleaning solution is preferably 100 parts per trillion (ppt) by mass or less, more preferably 10 ppt by mass or less, and even more preferably 1 ppt by mass or less. There is no particular lower limit, and 0 ppt by mass or more is preferred.

[0192] A conductive compound may be added to an organic processing liquid such as a rinse solution to prevent breakdown of the chemical solution piping and various parts (filters, O-rings, tubes, etc.) due to static charging and subsequent electrostatic discharge. The conductive compound is not particularly limited, but examples include methanol. The amount added is not particularly limited, but in order to maintain favorable development or rinsing characteristics, it is preferably 10% by mass or less, more preferably 5% by mass or less. There is no particular lower limit, but 0.01% by mass or more is preferred. For the chemical solution piping, for example, stainless steel (SUS), or various piping coated with antistatically treated polyethylene, polypropylene, or fluororesin (such as polytetrafluoroethylene or perfluoroalkoxy resin), can be used. Similarly, for the filters and O-rings, antistatically treated polyethylene, polypropylene, or fluororesin (such as polytetrafluoroethylene or perfluoroalkoxy resin), can be used.

[0193] [Method for Manufacturing an Electronic Device] The method for manufacturing an electronic device of the present invention includes the above-described pattern formation method. Examples of the electronic device in this specification include those installed in electrical and electronic devices (such as home appliances, OA (Office Automation), media-related devices, optical devices, and communication devices).

[0194] The present invention will be described in more detail below with reference to the following examples. The materials, amounts used, ratios, treatment details, and treatment procedures 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 following examples.

[0195] [Various Components of Photosensitive Composition] The various components used in preparing the photosensitive composition or materials used in the evaluation are listed below.

[0196] [Specific Resins and Comparative Resins] Table 1 shows the structure of the monomer (M-PAG) having an onium salt group represented by formula (1) used in the synthesis of the resin. The monomer having an onium salt group represented by formula (1) is composed of the anion and cation shown in Table 1 below. For example, M-PAG-1 is a monomer composed of the cation CT-01 and the anion AN-01. In Table 1, Δε represents the value of the above-mentioned integrated value FY - integrated value FX. The ΔClogP value represents the difference between the ClogP value of cation Y and the ClogP value of cation X. The pKa represents the pKa of a compound obtained by replacing the cation of each monomer with a proton. For example, the pKa of M-PAG-01 is the pKa of a compound composed of the anion AN-01 and a proton. The integrated value FY - integrated value FX, pKa, and ClogP value were calculated using the methods described above. It should be noted that the cation CT-04 has an organometallic structure, that is, M-PAG-04 has an organometallic structure.

[0197]

[0198] The structures of the cations and anions constituting each of the above monomers are shown below.

[0199]

[0200]

[0201] <Synthesis of M-PAG-03> (CT-03-BF ４ Salt synthesis) BF of CT-03 was synthesized according to the synthesis method of compound 5a described in Organic & Biomolecular Chemistry (2020), 18(31), 6140-6146. ４ Salt (CT-03-BF ４ ) was synthesized.

[0202] (Synthesis of M-PAG-03) M-PAG-03 was synthesized according to the following scheme.

[0203]

[0204] p-Hydroxystyrene (15.0 g), isobutyl 2,3,4,5,6-pentafluorobenzenesulfonate (39.4 g), and cesium carbonate (60.3 g) were dissolved in acetonitrile (330 g) and stirred at room temperature (23°C) for 1 hour. Ethyl acetate (400 mL) was added to the resulting mixture, and the mixture was washed three times with water (300 mL). The solvent in the organic layer was then distilled off to obtain AN-01-IB. AN-01-IB and sodium iodide (20.3 g) were dissolved in acetonitrile (470 g) and stirred at 60°C for 1 hour. The resulting mixture was cooled to room temperature and filtered to obtain AN-01-Na. 100 g of a 1:9 water / methanol mixture was added to AN-01-Na to prepare solution A. CT-03-BF ４ Solution B was prepared by adding 100 g of a 1:9 water / methanol mixed solution to the salt (42.0 g). Solution B was slowly added dropwise to solution A, and the mixture was stirred at 25°C for approximately 2 hours. After stirring, the precipitate was filtered. The precipitate was dissolved in methylene chloride (200 mL) and washed with 0.1 mol / L hydrochloric acid (200 mL) and water (200 mL). The solvent was distilled off to obtain M-PAG-03 (58.1 g) (yield: 92%).

[0205] M-PAGs other than those mentioned above were synthesized according to the synthesis method for M-PAG-03.

[0206] The structures of the monomers other than M-PAG used in the synthesis of the resins are shown below: M-MT-01 to M-MT-03 have organometallic structures.

[0207]

[0208] <Synthesis of M-MT-01> M-MT-01 was synthesized according to the synthesis method for compound C3 in JP-A-2023-122060.

[0209] Monomers (M-MT) having organometallic structures other than those mentioned above were synthesized according to the synthesis method for M-MT-01.

[0210] Table 2 shows the compositions of the specific resins and comparative resins PL-01 to PL-13 used in the examples and comparative examples. The content of each repeating unit is the mass ratio (mol %) of each repeating unit to all repeating units. The type of each repeating unit is shown by the type of monomer corresponding to each repeating unit. The table also shows the weight average molecular weight (Mw) and polydispersity index (PDI) of each resin. Mw and PDI were measured by GPC (carrier: tetrahydrofuran (THF)) (in terms of polystyrene). The content of each repeating unit in the resin is １３ Measurement was performed by C-NMR (Nuclear Magnetic Resonance).

[0211]

[0212] <Synthesis of Resin PL-03> Cyclohexanone (8 g) was heated to 80°C under a nitrogen stream. While stirring this solution, a mixed solution of M-PAG-03 (4.1 g), M-MT-01 (1.4 g), cyclohexanone (32 g), and dimethyl 2,2'-azobisisobutyrate [V-601, Fujifilm Wako Pure Chemical Industries, Ltd.] (0.5 g) was added dropwise over 6 hours to obtain a reaction solution. After completion of the dropwise addition, the reaction solution was stirred at 80°C for an additional 2 hours. The resulting reaction solution was allowed to cool and then reprecipitated with a large amount of ethyl acetate / heptane (mass ratio 6 / 4), followed by filtration. The resulting solid was vacuum dried to obtain 3.3 g of PL-03.

[0213] Resins other than resin PL-03 were synthesized according to the above method.

[0214] [Other solid contents] PAG-01: photoacid generator, an onium salt compound consisting of the above CT-01 and the below-mentioned AN-04 PDQ-01: acid diffusion controller, an onium salt compound consisting of the above CT-01 and the below-mentioned AN-05

[0215]

[0216] [Solvents] SL-01: Propylene glycol monomethyl ether acetate (PGMEA) SL-02: Propylene glycol monomethyl ether (PGME) SL-03: Cyclohexanone SL-04: γ-butyrolactone SL-05: Ethyl lactate SL-06: Diacetone alcohol MSL-01 to 06: Mixed solvents with the compositions shown in the table below. In the table, the numbers for each component represent the content (mass%) of each solvent. For example, MSL-01 is a mixed solvent of 60 mass% SL-01 (PGMEA) and 40 mass% SL-02 (PGME).

[0217]

[0218] [Developer and Rinse Solution] D-01: 2.38% by mass tetramethylammonium hydroxide aqueous solution D-02: Pure water D-03: Butyl acetate D-04: n-undecane D-05: 2-heptanone MD-01 to MD-03: Mixed solvents with the compositions shown in the table below. In the table, the numbers for each component indicate the content (% by mass) of each solvent. For example, MD-01 is a mixed solvent of 90% by mass of D-03 (butyl acetate) and 10% by mass of D-04 (n-undecane).

[0219]

[0220] [Preparation of Photosensitive Compositions] The resins shown in Table 5 below, and, unless otherwise specified, the photoacid generators and acid diffusion controllers, were used in the amounts shown in Table 5 and mixed with the solvents shown in Table 3 to achieve the solids concentrations shown in Table 5. The resulting mixtures were then filtered, in this order, first through a polyethylene filter with a pore size of 50 nm, then through a nylon filter with a pore size of 10 nm, and finally through a polyethylene filter with a pore size of 5 nm, to prepare photosensitive compositions (PR-1 to PR-13). In the photosensitive compositions, the solids refer to all components other than the solvent. In Table 5, the content (mass%) of each component other than the solvent indicates the content (mass%) of each component relative to the total solids in the photosensitive composition.

[0221]

[0222] [Evaluation] <Pattern Formation> An underlayer film-forming composition AL412 (manufactured by Brewer Science) was applied to a silicon wafer with a diameter of 300 mm and baked at 205°C for 60 seconds to form an underlayer film with a thickness of 20 nm. A photosensitive composition shown in Table 6 below was applied to the underlayer film, followed by a pre-exposure bake (Post Applied Bake; PAB) at 120°C to form a resist film with a thickness of 50 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 while varying the exposure dose using an EUV scanner NXE3400 (NA 0.33) manufactured by ASML. A hexagonal array contact hole mask (dark field mask) with a pitch of 36 nm and an opening size of 20 nm was used as the reticle. Thereafter, unless otherwise specified, a 60-second post-exposure bake (PEB) was performed at the temperature shown in Table 6 (in the table below, the PEB after patterned exposure is referred to as "PEB1"). The wafer was then flood-exposed (full-surface exposure) using a UV exposure device at the exposure wavelength and exposure dose shown in Table 6, and unless otherwise specified, a 60-second PEB was performed at the temperature shown in Table 6 (in the table below, the PEB after flood exposure is referred to as "PEB2"). The wafer was then developed for 30 seconds with the developer shown in Table 6, and, unless otherwise specified, rinsed by pouring the rinse solution shown in Table 6 for 10 seconds while rotating the wafer at 1000 rpm, followed by rotating the wafer at 4000 rpm for 30 seconds, thereby obtaining a positive-tone contact hole pattern with a pitch of 36 nm.

[0223] <LCDU Evaluation> Using a scanning electron microscope (SEM, CG6300 manufactured by Hitachi High-Technologies Corporation), 2000 holes were observed, and the CD (critical dimension) variation of holes with an average hole CD of 18 nm was defined as LCDU (unit: nm). The smaller the LCDU value, the better.

[0224] [Results] Table 6 below shows the photosensitive compositions used, the pattern formation conditions, and the LCDU values.

[0225]

[0226] From the results shown in the above table, it was confirmed that the photosensitive composition of the present invention can form a pattern with a small LCDU.

[0227] Comparison of Examples 1 to 5 confirmed that the effects of the present invention are more excellent when cation X is a cation that changes structure by the action of an acid to form a carbon-carbon multiple bond. Comparison of Examples 1 to 5 confirmed that the effects of the present invention are more excellent when the ΔClogP value is 1.2 or more, and even more excellent when the ΔClogP value is 2.0 or more. Comparison of Examples 1 and 6 confirmed that the effects of the present invention are more excellent when the C in the monomer having an onium salt group represented by formula (1) ＋ It was confirmed that the effects of the present invention are more excellent when the pKa of the compound obtained by replacing the cation represented by the formula (I) with a proton is −3.0 or less. A comparison of Examples 1, 7, and 8 confirmed that the effects of the present invention are more excellent when the metal atom of the organometallic structure and the organometallic compound is at least one selected from the group consisting of Sn and Bi.

Claims

1. A photosensitive composition comprising a resin having repeating units derived from a monomer containing an onium salt group represented by formula (1) and consisting of an anionic group and a cation, wherein the resin has an organometallic structure or the photosensitive composition contains an organometallic compound different from the resin, wherein the compound in the monomer, in which the cation in formula (1) is replaced with a proton, has an acid dissociation constant of -1.0 or less, wherein the cation is a cation whose structure changes under the action of acid, and wherein the cation before its structure changes under the action of acid is designated as cation X and the cation after its structure changes under the action of acid is designated as cation Y, the integrated value of the molar absorption coefficients of cation Y at wavelengths of 200 to 450 nm is greater than the integrated value of the molar absorption coefficients of cation X at wavelengths of 200 to 450 nm, and the onium salt group consisting of the anionic group and the cation Y generates an acid when irradiated with light of any wavelength between 200 and 450 nm. Formula (1) *-A － C ＋ In formula (1), A － represents an anionic group, C ＋ represents a cation, and * represents a bonding site.

2. The photosensitive composition according to claim 1, which satisfies at least one of requirements Q1 and Q2. Requirement Q1: The photosensitive composition contains an acid diffusion controller different from the resin. Requirement Q2: The resin has a repeating unit that has acid diffusion control properties.

3. The photosensitive composition according to claim 1, wherein the cation X is a cation whose structure changes when acted upon by an acid to form a multiple bond.

4. The photosensitive composition according to claim 1, wherein the cation X comprises at least one selected from the group consisting of cations represented by formula (CT-1) and cations represented by formula (CT-2). In formula (CT-1), R １ and R ２ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom. １ represents a single bond or a divalent linking group. １ represents a divalent aromatic ring group, and a represents an integer of 0 or more. ３ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom. ３ may be bonded to each other via a single bond or a divalent linking group to form a ring. ＋ Two or more groups directly bonded to L may be bonded to each other via a single bond or a divalent linking group to form a ring. ２ represents a single bond, an ethenylene group, an ethynylene group, a carbonyl group, a sulfinyl group, or a sulfonyl group. １ represents a group represented by any one of formulas (S-1) to (S-3). b represents 0 or 1. T １ represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, or a group represented by formula (T1). １ and T １ and may be bonded to each other via a single bond or a divalent linking group to form a ring. Ｓ１ ~R Ｓ４ R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom. Ｓ１ and R Ｓ２ may be bonded to each other via a single bond or a divalent linking group to form a ring, R Ｓ３ and R Ｓ４ may be bonded to each other via a single bond or a divalent linking group to form a ring. Ｓ５ and R Ｓ６ R each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom. Ｓ５ and R Ｓ６ may be bonded to each other via a single bond or a divalent linking group to form a ring. Ｓ１ and X Ｓ２ each independently represents an oxygen atom or a sulfur atom. Ｓ１ and Y Ｓ２ each independently represents a hydrocarbon group having 1 to 20 carbon atoms and a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom, provided that the heteroatom is located at the linking site of the hydrocarbon group having 1 to 20 carbon atoms and a heteroatom. Ｔ１ represents a single bond, an ethenylene group, an ethynylene group, a carbonyl group, a sulfinyl group, or a sulfonyl group. Ｔ１ represents an aromatic ring group having a valence of e+f+1, and e represents an integer of 0 or more. Ｔ１ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom. Ｔ１ may be bonded to each other via a single bond or a divalent linking group to form a ring. Ｔ１ R each independently represents a group represented by any one of the formulas (S-1) to (S-3). Ｔ２ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a hydrogen atom or a heteroatom, and f represents an integer of 0 to 4, provided that b+f is an integer of 1 to 4. In formula (CT-2), R ４ represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom. ３ represents a single bond or a divalent linking group. ２ represents a c+2-valent aromatic ring group, and c represents an integer of 0 or more. ５ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, a hydroxy group, a mercapto group, an amino group, a nitro group, a phosphino group, a silyl group, or a halogen atom. ５ may be bonded to each other via a single bond or a divalent linking group to form a ring. ＋ The two groups directly bonded to L may be bonded to each other via a single bond or a divalent linking group to form a ring. ４ represents a single bond, an ethenylene group, an ethynylene group, a carbonyl group, a sulfinyl group, or a sulfonyl group. ２ represents a group represented by any one of the formulas (S-1) to (S-3). ２ represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms which may have a heteroatom, or a group represented by the formula (T1). ２ and T ２ and may be bonded to each other via a single bond or a divalent linking group to form a ring. d represents 0 or 1, provided that d+f is an integer of 1 to 4.

5. The photosensitive composition according to claim 1, wherein the metal atom in the organometallic structure and the organometallic compound is at least one selected from the group consisting of Sn, Bi, Ge, Si, As, Se, Sb, Te, Pb, and Po.

6. The photosensitive composition according to claim 1, wherein the repeating unit derived from a monomer containing an onium salt group composed of an anionic group and a cation, represented by formula (1), is a repeating unit represented by formula (UA-1). In formula (UA-1), R ａ１ ~R ａ３ each independently represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, or an alkoxycarbonyl group. ａ１ represents a single bond or a divalent linking group. － represents an anionic group. ＋ represents a cation.

7. The photosensitive composition according to claim 1, wherein the organometallic structure and the organometallic compound have a partial structure represented by formula (2): Formula (2) (R) ｎ -M-Ar In formula (2), M represents a metal atom, Ar represents an aromatic ring, n represents the valence of the metal atom minus 1, and each R independently represents a substituent.

8. A resist film formed using the photosensitive composition according to any one of claims 1 to 7.

9. A pattern formation method comprising the steps of: forming a resist film on a substrate using the photosensitive composition according to any one of claims 1 to 7; irradiating the resist film with light having a wavelength of less than 200 nm to perform pattern exposure; exposing the pattern-exposed resist film by irradiating it with light having a wavelength of 200 to 450 nm; and developing the exposed resist film using a developer.

10. The pattern formation method according to claim 9, wherein an acid is generated by irradiation with light having a wavelength of less than 200 nm, the acid changes the structure of the cation X to generate the cation Y, and an acid is generated from an onium salt group consisting of the anionic group and the cation Y by irradiation with light having a wavelength of any one of 200 to 450 nm.

11. The pattern forming method according to claim 9, wherein the developer is an organic solvent-based developer.

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

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