Polymer compound production method

Abstract

Provided is a method for producing a polymer compound which has more uniform solubility in a developer and is useful as a polymer for a photoresist. This method for producing a polymer compound is a liquid-liquid extraction method, involving a polymerization step for polymerizing a monomer composition that includes a monomer, a polymerization solvent, and a polymerization initiator to obtain a polymerization reaction product including the polymer compound, and a recovery step for extracting and separating the polymer compound using a plurality of solvents, and recovering same, wherein a solvent A and a solvent B are used in the recovery step; the solvent A is an organic solvent having a Hansen solubility parameter (HSP) value in which δD = 10-20, 0 ≤ δP < 2, and δH = 0-4; the solvent B is an organic solvent having an HSP value in which δD = 10-20, δP = 5-15, and δH = 4-40; and in the recovery step, the polymer compound is extracted into the solvent B phase, a low molecular component in the polymerization reaction product is extracted into the solvent A phase, and the solvent B phase is separated and recovered.

Description

Method for producing polymer compounds

[0001] The present invention relates to a method for producing a polymer compound. This application claims priority based on Japanese Patent Application No. 2024-106765, filed on July 2, 2024, the contents of which are incorporated herein by reference.

[0002] Photoresist polymers used in forming fine circuit patterns in semiconductors are produced by polymerizing monomers and then purifying them to remove unreacted monomers, polymerization initiators, etc. A common purification method is reprecipitation purification, in which the polymerization reaction solution after polymerization or a solution of the resulting polymer dissolved in a good solvent is mixed with a poor solvent to precipitate the target polymer and perform solid-liquid separation. Reprecipitation purification is useful as a method for removing low-molecular-weight compounds such as unreacted monomers and polymerization initiators that are also soluble in the poor solvent.

[0003] Patent Document 1 discloses a method for producing a photoresist polymer, which includes a polymerization step of solution-polymerizing a monomer in a solvent, and a reprecipitation step of reprecipitating and purifying the polymer by adding dropwise a solution containing the polymer after polymerization to a reprecipitation solvent consisting of water and methanol.

[0004] Japanese Patent Application Laid-Open No. 2005-320444

[0005] In recent years, advances in lithography technology have led to rapid advances in miniaturization. Accordingly, in order to achieve more uniform solubility in developers, polymers for photoresists with smaller molecular weights, simpler structures, and narrower molecular weight distributions are required. However, because polymers with small molecular weights and simpler structures have high solubility in solvents, it is difficult to stably recover the polymers by reprecipitation purification while sufficiently narrowing the molecular weight distribution and sufficiently removing unreacted monomers, polymerization initiators, etc., and there are issues with uniformity of purification.

[0006] A primary object of the present invention is to provide a method for producing a polymeric compound which has more uniform solubility in a developer and is useful as a photoresist polymer.

[0007] The present invention includes the following aspects: [1] A method for producing a polymer compound, comprising: a polymerization step of polymerizing a monomer composition containing a monomer, a polymerization solvent, and a polymerization initiator to obtain a polymerization reaction product containing a polymer compound; and a recovery step of extracting, separating, and recovering the polymer compound using a plurality of solvents, wherein the recovery step is a liquid-liquid extraction method using solvent A and solvent B, wherein solvent A is an organic solvent having Hansen Solubility Parameters (hereinafter referred to as HSP), which are expressed in three terms of δD, δP, and δH, such that δD = 10 to 20, 0≦δP < 2, and δH = 0 to 4, and solvent B is an organic solvent having HSP values ​​of δD = 10 to 20, δP = 5 to 15, and δH = 4 to 40, and wherein the recovery step distributes the polymer compound into the solvent B phase, distributes low-molecular-weight components in the polymerization reaction product into the solvent A phase, and separates and recovers the solvent B phase. [2] The method for producing a polymer compound according to [1], wherein the recovery step uses a combination of solvent B1 and solvent B2 as solvent B, wherein solvent B1 is an organic solvent having HSP values ​​of δD = 10 to 20, δP = 5 to 15, and δH = 11 to 40, and solvent B2 is an organic solvent having HSP values ​​of δD = 10 to 20, δP = 5 to 15, and δH = 4 to 10. [3] The method for producing a polymer compound according to [1] or [2], wherein the recovery step further uses solvent C, wherein solvent C is an organic solvent having HSP values ​​of δD = 10 to 20, 2≦δP<5, and δH = 3 to 10. [4] The method for producing a polymer compound according to any of [1] to [3], further comprising a reprecipitation purification step of performing reprecipitation purification on the polymerization reaction product or the polymer compound before or after the recovery step. [5] The method for producing a polymer compound according to any one of [1] to [4], further comprising a solvent substitution step of adding a solvent D having a boiling point higher than that of solvent B to solvent B in which the polymer compound has been dissolved after the recovery step, and partially evaporating the solvent from the solution containing the polymer compound by distillation under reduced pressure to obtain a solution of the polymer compound containing solvent D. [6] The method for producing a polymer compound according to any one of [1] to [5], further comprising repeating the extraction and separation operation of the polymer compound by the liquid-liquid extraction method two or more times in the recovery step.[7] The method for producing a polymer compound according to any one of [1] to [6], wherein the polymer compound has a phenolic hydroxyl group. [8] The method for producing a polymer compound according to [1] to [7], wherein the polymer compound has an acid-leaving group. [9] The method for producing a polymer compound according to [1] to [8], wherein the polymer compound is used as a photoresist polymer.

[0008] According to the present invention, there is provided a method for producing a polymer compound which has more uniform solubility in a developer and is useful as a photoresist polymer.

[0009] The definitions of terms used in this specification are as follows. The Hansen solubility parameter (HSP) is a parameter divided into three components: a dispersion term δD, a polar term δP, and a hydrogen bonding term δH, and expressed in three-dimensional space. The dispersion term δD represents the energy derived from dispersion forces, the polar term δP represents the energy derived from dipole-dipole forces, and the hydrogen bonding term δH represents the energy derived from hydrogen bonding forces. The HSP [δD, δP, δH] of a solvent can be easily estimated from its chemical structure, for example, by using computer software Hansen Solubility Parameters in Practice (HSPiP). In the present invention, for solvents registered in the HSPiP version 5.4.08 database, the value is used, and for solvents not in the database, the value estimated by HSPiP version 5.4.08 is used. The weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of a polymer compound are values ​​determined by gel permeation chromatography in terms of polystyrene. A "structural unit" refers to a unit (atomic group) formed from one molecule of a monomer. An "acid-leaving group" refers to a group having a bond that is cleaved by acid, and a part or all of the acid-leaving group is cleaved from the main chain of the polymer upon cleavage of the bond. "(Meth)acrylic acid" refers to acrylic acid or methacrylic acid. "(Meth)acrylate" refers to acrylate or methacrylate. "(Meth)acryloyloxy" refers to acryloyloxy or methacryloyloxy. A numerical range indicated by "to" means that the values ​​before and after it are included as the lower and upper limits.

[0010] [Polymer Compound] First, a polymer compound (hereinafter also referred to as "polymer compound (P)") produced by the polymer compound production method according to the embodiment will be described. The polymer compound (P) has a narrow molecular weight distribution and uniform solubility in a developer. Furthermore, the polymer compound (P) is highly uniformly purified and contains few impurities other than the polymer compound (P), such as unreacted monomers and polymerization initiators. Therefore, it is useful as a photoresist polymer, and is particularly suitable for use as an EUV photoresist polymer, i.e., a photoresist polymer used in EUV (wavelength: 13.5 nm) lithography technology. The polymer compound (P) can also be used as an ArF photoresist polymer, i.e., a photoresist polymer used in ArF excimer laser (wavelength: 193 nm) lithography technology. The polymer compound (P) is particularly useful as a photoresist polymer for EUV applications, in which the resist pattern width is narrow.

[0011] Since the larger the molecular weight of the polymer compound contained in the resist, the more improved the solubility contrast during development, the Mw of the polymer compound (P) is preferably 3,000 or more, more preferably 3,500 or more. Furthermore, since the smaller the molecular weight of the polymer compound contained in the resist, the more improved the solubility in the developer, the Mw of the polymer compound (P) is preferably 15,000 or less, more preferably 14,000 or less. The lower and upper limits of the Mw of the polymer compound (P) can be arbitrarily combined, and for example, are preferably 3,000 or more and 15,000 or less, more preferably 3,500 or more and 14,000 or less.

[0012] Since the smaller the Mw / Mn, the more uniform the solubility in the developer, the Mw / Mn of the polymer compound (P) is preferably 2.00 or less, and more preferably 1.90 or less. The lower limit of the Mw / Mn of the polymer compound (P) is not particularly limited, but may be, for example, 1.05 or more, or 1.10 or more. The lower and upper limits of the Mw / Mn of the polymer compound (P) can be arbitrarily combined, and for example, 1.05 or more and 2.00 or less are preferred, and 1.10 or more and 1.90 or less are more preferred. The Mw and Mw / Mn of the polymer compound (P) are the Mw and Mw / Mn of the polymer compound (P) after the recovery step described below.

[0013] The polymer compound (P) preferably has a phenolic hydroxyl group in the molecule. The polymer compound (P) also preferably has an acid-leaving group. The presence of a phenolic hydroxyl group in the molecule results in excellent solubility of the resist film in a developer and excellent etching resistance. The presence of an acid-leaving group results in excellent sensitivity and resolution of the resist film. A suitable example of the polymer compound (P) is a polymer having a structural unit based on a monomer having a phenolic hydroxyl group, and more preferably a polymer having a structural unit based on a monomer having an acid-leaving group and a structural unit based on a monomer having a phenolic hydroxyl group. The polymer may have a structural unit based on a monomer other than the monomer having the acid-leaving group and the monomer having the phenolic hydroxyl group.

[0014] Examples of the monomer having an acid-leaving group include a (meth)acrylic acid ester having an acid-leaving group, and a compound having an acid-leaving group and an ethylenic double bond (excluding (meth)acrylic acid esters). Examples of the acid-leaving group include acetal types and tertiary ester types, but the monomer having an acid-leaving group preferably includes a compound represented by the following formula (m1) (hereinafter also referred to as "compound (m1)") because of its excellent acid-leaving property.

[0015]

[0016] However, in formula (m1), R １ represents a hydrogen atom or a methyl group, R ２ ~R ４ R each independently represents a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, aralkyl group or alkenyl group which may have a heteroatom such as an oxygen atom or a sulfur atom or a halogen atom. ３ and R ４ may be bonded to each other to form a ring. １ represents a substituted or unsubstituted divalent chain hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted divalent cyclic hydrocarbon group having 3 to 20 carbon atoms which may have a heteroatom or a halogen atom, or a single bond; X ２represents a divalent chain hydrocarbon group having 1 to 12 carbon atoms, and n1 is an integer of 0 to 3.

[0017] R ２ ~R ４ The alkyl group of R may be a straight chain or a branched chain. ２ ~R ４ The number of carbon atoms in the alkyl groups R is preferably 1 to 10, and more preferably 1 to 6. ２ ~R ４ Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a hexyl group, an octyl group, a decyl group, etc. At least one carbon atom or hydrogen atom in the alkyl group may be substituted with an oxygen atom, a sulfur atom, a halogen atom, etc.

[0018] R ２ ~R ４ The cycloalkyl group may be monocyclic or polycyclic. Preferred monocyclic groups are cycloalkyl groups having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, and cyclodecyl. Preferred polycyclic groups are cycloalkyl groups having 6 to 20 carbon atoms, such as adamantyl, norbornyl, isobornyl, camphanyl, dicyclopentyl, α-pinel, tricyclodecanyl, tetracyclododecyl, and androstanyl. At least one carbon atom or hydrogen atom in the cycloalkyl group may be substituted with an oxygen atom, sulfur atom, halogen atom, or the like.

[0019] R ２ ~R ４ The aryl group in R is preferably an aryl group having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, an anthryl group, or a fluorenyl group. At least one carbon atom or hydrogen atom in the aryl group may be substituted with an oxygen atom, a sulfur atom, a halogen atom, or the like. ２ ~R ４ The aralkyl group of R is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group.２ ~R ４ The alkenyl group is preferably an alkenyl group having 2 to 10 carbon atoms, such as a vinyl group, an allyl group, a butenyl group, or a cyclohexenyl group.

[0020] R ３ and R ４ When R are bonded to each other to form a ring, the ring is a monocyclic or polycyclic alicyclic group which may have an etheric oxygen atom between the carbon-carbon bonds. ３ and R ４ The number of carbon atoms constituting the ring is preferably 3 to 10, more preferably 4 to 10, and even more preferably 5 or 6, and the ring is preferably a cycloalkyl group (monocyclic or polycyclic). Examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group.

[0021] R ２ ~R ４ Examples of the substituent that the alkyl group, cycloalkyl group, aryl group, aralkyl group or alkenyl group may have include a halogen atom, a hydroxyl group, a cyano group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, a halogenated alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a thioether group having 1 to 12 carbon atoms, and an ester group having 1 to 12 carbon atoms.

[0022] X １ The divalent chain hydrocarbon group X may be a straight chain or a branched chain. １ The divalent chain hydrocarbon group preferably has 1 to 16 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 1 to 8 carbon atoms. １ The divalent chain hydrocarbon group may be an alkylene group or an alkenylene group. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, and a hexylene group. Examples of the alkenylene group include -CH=CH-, -CH=CH-CH ２ -, -CH ２ -CH=CH-CH ２- etc.

[0023] X １ The divalent cyclic hydrocarbon group may be a monocyclic or polycyclic group. １ The divalent cyclic hydrocarbon group may be a group consisting of a saturated hydrocarbon or a group consisting of an unsaturated hydrocarbon. As the monocyclic type, a cycloalkylene group having 3 to 10 carbon atoms is preferred, and examples thereof include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cyclooctylene group, and a cyclodecylene group. As the polycyclic type, a cycloalkylene group having 6 to 20 carbon atoms is preferred, and examples thereof include an adamantylene group and a norbornylene group. X １ The divalent cyclic hydrocarbon group may be an arylene group such as a phenylene group or a naphthylene group, in which at least one carbon atom or hydrogen atom may be substituted with an oxygen atom, a sulfur atom, a halogen atom, or the like.

[0024] X １ Examples of the substituent that the chain hydrocarbon group or cyclic hydrocarbon group may have include a halogen atom, a hydroxyl group, a cyano group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, a halogenated alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a thioether group having 1 to 12 carbon atoms, and an ester group having 1 to 12 carbon atoms.

[0025] X １ As the alkyl group, a single bond, an alkylene group, a cycloalkylene group, or an arylene group is preferable, a single bond, an alkylene group, or an arylene group is more preferable, and a single bond is particularly preferable.

[0026] X ２ The divalent chain hydrocarbon group X may be a straight chain or a branched chain. ２ The carbon number of the divalent chain hydrocarbon group is preferably 1 to 8, and more preferably 1 to 6. ２The divalent chain hydrocarbon group may be an alkylene group or an alkenylene group. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, and a hexylene group. Examples of the alkenylene group include -CH=CH-, -CH=CH-CH ２ -, -CH ２ -CH=CH-CH ２ -, etc. In addition, X ２ At least one carbon atom or hydrogen atom in the divalent chain hydrocarbon group may be substituted with an oxygen atom, sulfur atom, halogen atom, or the like.

[0027] X ２ Examples of the substituent that the chain hydrocarbon group may have include a halogen atom, a hydroxyl group, a cyano group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, a halogenated alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a thioether group having 1 to 12 carbon atoms, and an ester group having 1 to 12 carbon atoms.

[0028] n1 is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.

[0029] Examples of the compound (m1) include 1-methylcyclopentyl (meth)acrylate, 1-ethylcyclopentyl (meth)acrylate, 1-isopropylcyclopentyl (meth)acrylate, 1-tert-butyl-1-cyclopentyl (meth)acrylate, 1-phenylcyclopentyl (meth)acrylate, 1-vinylcyclopentyl (meth)acrylate, 1-methylcyclohexyl (meth)acrylate, and 1-ethylcyclohexyl (meth)acrylate. Examples of the compound (m1) include 1-methylcyclopentyl methacrylate, 1-ethylcyclopentyl (meth)acrylate, 1-isopropylcyclohexyl (meth)acrylate, 1-tert-butyl-1-cyclohexyl (meth)acrylate, 1-phenylcyclohexyl (meth)acrylate, 1-vinylcyclohexyl (meth)acrylate, 1-methyl-1-phenylethyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, and isopropyladamantyl (meth)acrylate. 1-methylcyclopentyl methacrylate, 1-ethylcyclopentyl (meth)acrylate, 1-isopropylcyclopentyl (meth)acrylate, and 1-tert-butyl-1-cyclopentyl (meth)acrylate are preferred as the compound (m1) because they have excellent lithography properties.

[0030] As the monomer having an acid-dissociable group, a compound represented by the following formula (m2) (hereinafter also referred to as "compound (m2)") may be used.

[0031]

[0032] However, in formula (m2), R ５ represents a hydrogen atom or a methyl group, Y １ represents a substituted or unsubstituted divalent chain hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted divalent cyclic hydrocarbon group having 3 to 20 carbon atoms which may have a heteroatom or a halogen atom, or a linking group containing a single bond or an ester bond; R ６ ~R ８R each independently represents a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, aralkyl group or alkenyl group which may have a heteroatom such as an oxygen atom or a sulfur atom or a halogen atom. ７ and R ８ may be bonded to each other to form a ring. n2 is an integer of 0 to 11. Ring Z may be a substituted or unsubstituted ring made of a saturated or unsaturated hydrocarbon, and at least one carbon atom or hydrogen atom may be substituted with an oxygen atom, a sulfur atom, a halogen atom, or the like.

[0033] Y １ Examples of Y include -C(=O)O-. １ is preferably a single bond. ６ ~R ８ The alkyl group of R may be a straight chain or a branched chain. ６ ~R ８ The number of carbon atoms in the alkyl groups R is preferably 1 to 10, and more preferably 1 to 6. ６ ~R ８ Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a hexyl group, an octyl group, a decyl group, etc. At least one carbon atom or hydrogen atom in the alkyl group may be substituted with an oxygen atom, a sulfur atom, a halogen atom, etc.

[0034] R ６ ~R ８The cycloalkyl group may be monocyclic or polycyclic. Preferred monocyclic groups are cycloalkyl groups having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, and cyclodecyl. Preferred polycyclic groups are cycloalkyl groups having 6 to 20 carbon atoms, such as adamantyl, norbornyl, isobornyl, camphanyl, dicyclopentyl, α-pinel, tricyclodecanyl, tetracyclododecyl, and androstanyl. At least one carbon atom or hydrogen atom in the cycloalkyl group may be substituted with oxygen, sulfur, a halogen atom, or the like.

[0035] R ６ ~R ８ The aryl group in R is preferably an aryl group having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, an anthryl group, or a fluorenyl group. At least one carbon atom or hydrogen atom in the aryl group may be substituted with an oxygen atom, a sulfur atom, a halogen atom, or the like. ６ ~R ８ The aralkyl group of R is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group. ６ ~R ８ The alkenyl group is preferably an alkenyl group having 2 to 10 carbon atoms, such as a vinyl group, an allyl group, a butenyl group, or a cyclohexenyl group.

[0036] R ７ and R ８ may be bonded to each other to form a ring. ７ and R ８ When R are bonded to each other to form a ring, the ring is a monocyclic or polycyclic alicyclic group which may have an etheric oxygen atom between the carbon-carbon bonds. ７ and R ８ The number of carbon atoms constituting the ring is preferably 3 to 10, more preferably 4 to 10, and even more preferably 5 or 6.

[0037] n2 is preferably an integer of 2 to 10, and more preferably an integer of 3 to 9. Ring Z is a ring having 3 to 14 carbon atoms, and may be a ring made of a saturated hydrocarbon or a ring made of an unsaturated hydrocarbon, and may be a monocyclic or polycyclic ring. Examples of monocyclic rings include a cyclopentylene group and a cyclohexylene group. Examples of polycyclic rings include a norbornylene group and an adamantylene group. Examples of arylene groups include a phenylene group and a naphthylene group. At least one carbon atom or hydrogen atom in ring Z may be substituted with an oxygen atom, a sulfur atom, a halogen atom, or the like. Ring Z is preferably an aryl group such as a phenyl group or a naphthyl group.

[0038] Examples of the compound (m2) include tert-butyl styrene-4-carboxylate and tert-amyl styrene-4-carboxylate.

[0039] The monomer having an acid-dissociable group may be used alone or in combination of two or more kinds.

[0040] The structural unit based on a monomer having a phenolic hydroxyl group has a hydroxyl group which is both a "polar group" and a "hydrophilic group," contributing to the solubility of the resist film in a developer. In addition, the structural unit has an aromatic ring, contributing to the etching resistance of the resist film.

[0041] The monomer having a phenolic hydroxyl group may be a compound having a phenolic hydroxyl group and a polymerizable unsaturated bond, and is preferably a compound having a phenolic hydroxyl group and an ethylenic double bond. Because of its excellent solubility in a developer and etching resistance, the monomer having a phenolic hydroxyl group preferably includes a compound represented by the following formula (m3) (hereinafter also referred to as "compound (m3)"):

[0042]

[0043] However, in formula (m3), R ９ represents a hydrogen atom or a methyl group, Y ２ represents a linking group containing a single bond or an ester bond; k represents an integer of 1 to 5;

[0044] Y ２Examples of Y include -C(=O)O-. ２ k is preferably an integer of 1 to 3, and more preferably an integer of 1 to 2.

[0045] Examples of compound (m3) include p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, 1,2-dihydroxystyrene, 3,4-dihydroxystyrene, 3,5-dihydroxystyrene, 2,3,4-trihydroxystyrene, 4-hydroxyphenyl (meth)acrylate, 3-hydroxyphenyl (meth)acrylate, 2-hydroxyphenyl (meth)acrylate, and 3,4-dihydroxyphenyl (meth)acrylate. Because of their excellent solubility in a developer and etching resistance, p-hydroxystyrene and m-hydroxystyrene are preferred as compound (m2). The monomer having a phenolic hydroxyl group may be used alone or in combination of two or more.

[0046] Other monomers are monomers that do not fall into either the category of monomers having an acid-leaving group or monomers having a phenolic hydroxyl group, such as monomers having a polar group (excluding monomers having a phenolic hydroxyl group), monomers having a hydrophilic group (excluding monomers having a phenolic hydroxyl group), and monomers having a photoacid-generating group. The structural unit based on a monomer having a polar group contributes to adhesion to a substrate, etc. The structural unit based on a monomer having a hydrophilic group contributes to solubility in a developer.

[0047] The polar group is a functional group having polarity or a group having a polar atomic group, and examples thereof include a hydroxyl group (excluding phenolic hydroxyl groups), a cyano group, an alkoxy group, a carboxyl group, an amino group, a carbonyl group, a group containing a fluorine atom, a group containing a sulfur atom, a group having a lactone skeleton, a group having a sultone skeleton, a group containing an acetal structure, and a group containing an ether bond. Examples of the hydrophilic group include -C(CF ３ ) ２Examples of such groups include —OH, a hydroxyl group (excluding phenolic hydroxyl groups), a cyano group, a methoxy group, a carboxyl group, a sulfo group, and an amino group. The hydroxyl group, the cyano group, the methoxy group, the carboxyl group, the sulfo group, and the amino group are polar groups and hydrophilic groups.

[0048] In terms of excellent adhesion to a substrate, etc., the other monomer is preferably a group having a lactone skeleton or a group having a sultone skeleton. In terms of excellent solubility of the polymer compound (P) in a developer, it is preferable that the other monomer has a hydroxyl group (excluding phenolic hydroxyl groups) or a cyano group, and it is more preferable that the other monomer has a hydroxyl group.

[0049] Examples of the lactone skeleton include lactone skeletons having a 4- to 20-membered ring. The lactone skeleton may be a monocyclic lactone ring, or may be a lactone ring condensed with an aliphatic or aromatic carbon ring or heterocyclic ring. Examples of the monomer having a lactone skeleton include compounds having a lactone skeleton and a polymerizable unsaturated bond, preferably compounds having a lactone skeleton and an ethylenic double bond, and more preferably (meth)acrylic acid esters having a lactone skeleton.

[0050] The monomer having a lactone skeleton is preferably a (meth)acrylic acid ester having a substituted or unsubstituted δ-valerolactone ring, a (meth)acrylic acid ester having a substituted or unsubstituted γ-butyrolactone ring, or a (meth)acrylic acid ester having a norbornane lactone ring, from the viewpoint of an excellent effect of improving adhesion to a substrate or the like. Examples of monomers having a lactone skeleton include β-(meth)acryloyloxy-β-methyl-δ-valerolactone, 4,4-dimethyl-2-methylene-γ-butyrolactone, β-(meth)acryloyloxy-γ-butyrolactone, β-(meth)acryloyloxy-β-methyl-γ-butyrolactone, α-(meth)acryloyloxy-γ-butyrolactone, 2-(1-(meth)acryloyloxy)ethyl-4-butanolide, (meth)acrylic acid pantoyl lactone, 5-(meth)acryloyloxy-2,6-norbornane carbolactone, 8-methacryloxy-4-oxatricyclo[5.2.1.02,6]decan-3-one, and 9-methacryloxy-4-oxatricyclo[5.2.1.02,6]decan-3-one. As the monomer having a lactone skeleton, α-(meth)acryloyloxy-γ-butyrolactone and β-(meth)acryloyloxy-γ-butyrolactone are preferred, and α-methacryloyloxy-γ-butyrolactone and β-methacryloyloxy-γ-butyrolactone are more preferred. The monomer having a lactone skeleton may be used alone or in combination of two or more.

[0051] Examples of the sultone skeleton include a 4- to 20-membered sultone (cyclic sulfonate ester) skeleton. The sultone skeleton may be a monocyclic sultone ring, or may be a sultone ring condensed with an aliphatic or aromatic carbon ring or heterocycle. Examples of monomers having a sultone skeleton include compounds having a sultone skeleton and a polymerizable unsaturated bond, preferably compounds having a sultone skeleton and an ethylenic double bond, and more preferably (meth)acrylic acid esters having a sultone skeleton.

[0052] As the monomer having a sultone skeleton, a (meth)acrylic acid ester having a norbornane sultone ring is preferred from the viewpoint of excellent adhesion to substrates, etc. Examples of the monomer having a sultone skeleton include β-(meth)acryloyloxy-β-methyl-δ-valerosultone, 4,4-dimethyl-2-methylene-γ-butylosultone, β-(meth)acryloyloxy-γ-butylosultone, β-(meth)acryloyloxy-β-methyl-γ-butylosultone, α-(meth)acryloyloxy-γ-butylosultone, (meth)acrylic acid pantoyl sultone, 5-(meth)acryloyloxy-2,6-norbornanecarbosultone, and 2-methacryloyloxyacetoxy-4,5-oxathiatricyclo[4.2.1.03,7]nonane=5,5-dioxide. The monomer having a sultone skeleton may be used alone or in combination of two or more kinds.

[0053] The structural unit based on other monomers preferably includes a structural unit based on a monomer having a hydrophilic group (excluding phenolic hydroxyl groups). Examples of the monomer having a hydrophilic group include compounds having a hydrophilic group and a polymerizable unsaturated bond, and preferred are compounds having a hydrophilic group and an ethylenic double bond. As the monomer having a hydrophilic group, in terms of excellent solubility in a developer, preferred are (meth)acrylic acid esters having a terminal hydroxyl group; derivatives having a substituent such as an alkyl group, a hydroxyl group, or a carboxyl group on the hydrophilic group of the monomer; and compounds of (meth)acrylic acid esters having a cyclic hydrocarbon group and a hydrophilic group such as a hydroxyl group or a carboxyl group as a substituent.

[0054] Examples of the (meth)acrylic acid ester having a cyclic hydrocarbon group include cyclohexyl (meth)acrylate, 1-isobornyl (meth)acrylate, adamantyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dicyclopentyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate.

[0055] Examples of monomers having a hydrophilic group include (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-n-propyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-hydroxyadamantyl (meth)acrylate, 2- or 3-cyano-5-norbornyl (meth)acrylate, and 2-cyanomethyl-2-adamantyl (meth)acrylate. In terms of excellent adhesion to substrates and the like, 3-hydroxyadamantyl (meth)acrylate, 3,5-dihydroxyadamantyl (meth)acrylate, 2- or 3-cyano-5-norbornyl (meth)acrylate, and 2-cyanomethyl-2-adamantyl (meth)acrylate are preferred, with 3-hydroxyadamantyl (meth)acrylate being more preferred. One type of monomer having a hydrophilic group may be used alone, or two or more types may be used in combination.

[0056] The structural units based on other monomers may include structural units based on monomers having a photoacid generating group, where the "photoacid generating group" is a group that forms an acid group such as a carboxylic acid group or a sulfonic acid group upon irradiation with light.

[0057] Examples of the monomer having a photoacid generating group include a compound represented by the following formula (m4) (hereinafter also referred to as "compound (m4)").

[0058]

[0059] However, in formula (m4), R １０ represents a hydrogen atom or a methyl group, L １ and L ２ each independently represents a single bond, an ether group, an ester group, a carbonate ester group, -L ３ -Ar-L ４ represents a linking group represented by -. ３ and L ４ each independently represents one or more linking groups selected from the group consisting of a single bond, an ether group, a thioether group, an ester group, and a carbonate ester group. Ar represents an arylene group which may have a substituent. A １ and A ２each independently represents a hydrocarbon group having 1 to 24 carbon atoms which may have a substituent, and a methylene group contained in the hydrocarbon group may be substituted with an ether group, a thioether group, a carbonyl group, or a sulfonyl group. n3 represents an integer of 0 to 2. B １ and B ２ each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms; A ＋ represents an organic counter ion.

[0060] L １ and L ２ At least one of the following is -L ３ -Ar-L ４ When L is a linking group represented by -, ３ and L ４ L each independently represents one or more linking groups selected from the group consisting of a single bond, an ether group, a thioether group, an ester group, and a carbonate ester group. ３ and L ４ When either one of the groups is a single bond, the other is preferably one or more selected from the group consisting of an ether group, a thioether group, an ester group, and a carbonate ester group. Ar represents an arylene group which may have a substituent, such as a phenyl group, a naphthalene group, a biphenyl group, or a fluorene group. Examples of the substituent include a halogen atom, a hydroxyl group, a cyano group, a fluorinated alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. The number of substituents may be one or more, and when there are more than one, they may be the same or different.

[0061] A １ and A ２ A each independently represents a hydrocarbon group having 1 to 24 carbon atoms which may have a substituent, and examples thereof include a chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a linking group which is a combination of two or more of these groups. １ and A ２Examples of the chain hydrocarbon group include an alkyl group or an alkenyl group. The alkyl group may be linear or branched, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a hexyl group, an octyl group, and a decyl group. The number of carbon atoms in the chain hydrocarbon group is preferably 1 to 20, more preferably 1 to 14, and even more preferably 1 to 10.

[0062] A １ and A ２ Examples of the alicyclic hydrocarbon group include monocyclic and polycyclic cycloalkyl groups. As the monocyclic group, a cycloalkyl group having 3 to 10 carbon atoms is preferred, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a cyclodecyl group. As the polycyclic group, a cycloalkyl group having 6 to 20 carbon atoms is preferred, and examples thereof include an adamantyl group, a norbornyl group, an isobornyl group, a camphanyl group, a dicyclopentyl group, an α-pinel group, a tricyclodecanyl group, a tetracyclododecyl group, and an androstanyl group. A １ and A ２ Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, a biphenyl group, and a fluorene group. The number of carbon atoms in the aromatic hydrocarbon group is preferably 5 to 14, and more preferably 5 to 10. １ and A ２ Examples of the substituent that the hydrocarbon group may have include a halogen atom, a hydroxyl group, a cyano group, and an alkoxy group.

[0063] B １ and B ２ The perfluoroalkyl group may be linear or branched. １ and B ２ are each independently preferably a fluorine atom or a trifluoromethyl group, and particularly preferably a fluorine atom.

[0064] A ＋The organic counter ion in the formula (I) is preferably an onium cation. Examples of the onium cation include a sulfonium cation, an iodonium cation, an ammonium cation, a benzothiazolium cation, and a phosphonium cation. Among these, a sulfonium cation and an iodonium cation are preferred, a sulfonium cation is more preferred, and an arylsulfonium cation is even more preferred. Examples of the aryl group contained in the arylsulfonium cation include a phenyl group, a naphthalene group, a biphenyl group, a phenyloxyphenyl group, and a fluorene group, with a phenyl group being particularly preferred. The hydrogen atom contained in the arylsulfonium cation may be substituted with a halogen atom, a hydroxyl group, a cyano group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, a fluorinated alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a thioether group having 1 to 12 carbon atoms, an ester group having 1 to 12 carbon atoms, or the like.

[0065] Specific examples of the compound (m4) include CH ２ = CHR １０ -C(=O)-O-CH ２ -CF ２ -SO ３ － S (C ６ H ５ ) ３ ＋ The monomer having a photoacid generating group may be used alone or in combination of two or more kinds.

[0066] The proportion of structural units based on monomers having an acid-leaving group in the polymer compound (P) is preferably 20 mol% or more, more preferably 25 mol% or more, and preferably 80 mol% or less, more preferably 70 mol% or less, relative to all structural units constituting the polymer compound (P). When the proportion of structural units based on monomers having an acid-leaving group is equal to or greater than the aforementioned lower limit, the sensitivity and resolution of the resist film are excellent. When the proportion of structural units based on monomers having an acid-leaving group is equal to or less than the aforementioned upper limit, the properties of structural units other than structural units based on monomers having an acid-leaving group are excellent, and the resist film has excellent adhesion to substrates and solubility in developers. The lower and upper limits of the proportion of structural units based on monomers having an acid-leaving group can be arbitrarily combined; for example, 20 to 80 mol% is preferred, and 25 to 70 mol% is more preferred.

[0067] The proportion of structural units based on monomers having phenolic hydroxyl groups in the polymer compound (P) is preferably 10 mol% or more, more preferably 15 mol% or more, and even more preferably 20 mol% or more, and is preferably 80 mol% or less, more preferably 70 mol% or less, and even more preferably 60 mol% or less, relative to all structural units constituting the polymer compound (P). When the proportion of structural units based on monomers having phenolic hydroxyl groups is equal to or greater than the aforementioned lower limit, etching resistance is excellent. When the proportion of structural units based on monomers having phenolic hydroxyl groups is equal to or less than the aforementioned upper limit, the properties of structural units other than structural units based on monomers having phenolic hydroxyl groups are excellent. The lower and upper limits of the proportion of structural units based on monomers having phenolic hydroxyl groups can be arbitrarily combined; for example, 10 to 80 mol% is preferred, 15 to 70 mol% is more preferred, and 20 to 60 mol% is even more preferred.

[0068] The total proportion of the structural units based on the monomer having an acid-leaving group and the structural units based on the monomer having a phenolic hydroxyl group in the polymer compound (P) is preferably 40 mol% or more, more preferably 50 mol% or more, and even more preferably 60 mol% or more, and is 100 mol% or less, preferably 95 mol% or less, and more preferably 90 mol% or less, relative to all structural units constituting the polymer compound (P). The lower and upper limits of this total proportion can be arbitrarily combined, and are, for example, preferably 40 to 100 mol%, more preferably 50 to 95 mol%, and even more preferably 60 to 90 mol%.

[0069] The proportion of structural units based on monomers having a lactone skeleton or a sultone skeleton in the polymer compound (P) is preferably 0 to 60 mol %, more preferably 0 to 50 mol %, and even more preferably 0 to 40 mol %, relative to all structural units constituting the polymer compound (P). When the proportion of structural units based on monomers having a lactone skeleton or a sultone skeleton is not more than the above upper limit, the properties of structural units other than these structural units are excellent.

[0070] The proportion of structural units based on monomers having a hydrophilic group (excluding phenolic hydroxyl groups) in the polymer compound (P) is preferably 0 to 40 mol %, more preferably 0 to 30 mol %, and even more preferably 0 to 20 mol %, relative to all structural units constituting the polymer compound (P). When the proportion of structural units based on monomers having a hydrophilic group is not more than the upper limit mentioned above, the properties of structural units other than these structural units are excellent.

[0071] The proportion of the structural units based on the monomer having a photoacid generating group in the polymer compound (P) is preferably 0 to 40 mol %, more preferably 0 to 30 mol %, and even more preferably 0 to 20 mol %, based on all structural units constituting the polymer compound (P). When the proportion of structural units based on the monomer having a photoacid generating group is not more than the upper limit mentioned above, the properties of structural units other than the structural units are excellent.

[0072] [Method for Producing Polymer Compound] The method for producing a polymer compound according to the embodiment includes the following polymerization step and recovery step. Polymerization step: A monomer composition containing a monomer, a polymerization solvent, and a polymerization initiator is polymerized to obtain a polymerization reaction product containing a polymer compound (P). Recovery step: The polymer compound (P) is extracted, separated, and recovered using multiple solvents. In the recovery step, a liquid-liquid extraction method using solvent A and solvent B is employed, and the polymer compound (P) is distributed into the solvent B phase, and low-molecular-weight components in the polymerization reaction product are distributed into the solvent A phase, and the solvent B phase is separated and recovered.

[0073] The method for producing a polymer compound according to the embodiment may further include the following reprecipitation purification step before or after the recovery step, as necessary, or may further include the following solvent substitution step after the recovery step. Reprecipitation purification step: The polymerization reaction product or the polymer compound (P) after the recovery step is subjected to reprecipitation purification. Solvent substitution step: Solvent D, which has a higher boiling point than solvent B, is added to solvent B in which polymer compound (P) after the recovery step has been dissolved, and the solvent from the solution containing the polymer compound is partially evaporated under reduced pressure to obtain a solution of polymer compound (P) containing solvent D.

[0074] (Polymerization Step) The polymerization method is not particularly limited, and examples thereof include radical polymerization methods such as bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization. Among these, solution polymerization is preferred. In solution polymerization, a polymerization reaction solution is obtained by radically polymerizing a monomer using a polymerization initiator in the presence of a polymerization solvent. In solution polymerization, the monomer and polymerization initiator may be continuously or dropwise supplied to a polymerization vessel. Dropping polymerization, in which the monomer and polymerization initiator are dropped into a polymerization vessel, is preferred because it minimizes variations in average molecular weight, molecular weight distribution, etc. due to differences in production lots and allows for the easy production of reproducible polymers. In dropping polymerization, the polymerization vessel is heated to a predetermined polymerization temperature, and then the monomer and polymerization initiator are dropped into the polymerization vessel, either independently or in any combination. The monomer may be dropped alone, or a monomer solution in which the monomer is dissolved in a polymerization solvent. The polymerization solvent and / or the monomers may be charged in advance into the polymerization vessel.

[0075] The polymerization initiator may be dissolved directly in the monomer, in the monomer solution, or in the polymerization solvent alone. The monomer and the polymerization initiator may be mixed in the same storage tank and then dropped into the polymerization vessel; they may be dropped into the polymerization vessel from separate storage tanks; or they may be mixed from separate storage tanks just before being fed into the polymerization vessel and then dropped into the polymerization vessel. One of the monomer and the polymerization initiator may be dropped first, and then the other may be dropped later, or both may be dropped at the same time.

[0076] The dropping rate may be constant until the end of the dropping, or may be changed in multiple stages depending on the consumption rate of the monomer or polymerization initiator. The dropping may be carried out continuously or intermittently.

[0077] The polymerization temperature is preferably 50 to 150°C. At a polymerization temperature of 50°C or higher, radicals can be generated from the initiator, such as an organic peroxide or an azo compound, to obtain the desired polymer compound. The polymerization temperature is more preferably 60°C or higher, and even more preferably 70°C or higher. Furthermore, at a polymerization temperature of 150°C or lower, excessive radical generation can be suppressed, allowing a polymer compound with the desired composition ratio and molecular weight to be obtained. The polymerization temperature is more preferably 100°C or lower, and even more preferably 90°C or lower. After the polymerization reaction is carried out for a predetermined time at a predetermined polymerization temperature, the polymerization reaction is terminated to obtain a polymerization reaction solution. The polymerization reaction is generally terminated by cooling the reaction solution, but it can also be terminated by adding a radical scavenger.

[0078] The polymerization reaction of the monomers is preferably carried out in an atmosphere in which the oxygen concentration in the gas phase in the reactor is 1% by volume or less. When the oxygen concentration is 1% by volume or less, the inhibitory effect on the polymerization reaction is small. The oxygen concentration is more preferably 0.1% by volume or less, even more preferably 0.01% by volume or less, and may be 0% by volume. In a suitable example, before the start of the polymerization reaction, the gas phase in the reactor is substituted with an inert gas having an oxygen concentration of 1% by volume or less. Examples of inert gases include nitrogen and rare gases. Nitrogen and argon are preferred, and nitrogen is more preferred, because they are inert to radicals and are commonly used industrially.

[0079] Examples of polymerization solvents include ethers, esters, ketones, amides, sulfoxides, aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons. Examples of ethers include linear ethers such as diethyl ether and propylene glycol monomethyl ether, and cyclic ethers such as tetrahydrofuran and 1,4-dioxane. Examples of esters include methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, propylene glycol monomethyl ether acetate, γ-butyrolactone, and methyl 2-hydroxyisobutyrate. Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Examples of amides include N,N-dimethylacetamide and N,N-dimethylformamide. Examples of sulfoxides include dimethyl sulfoxide. Examples of aromatic hydrocarbons include benzene, toluene, and xylene. Examples of aliphatic hydrocarbons include hexane. Examples of alicyclic hydrocarbons include cyclohexane. As the polymerization solvent, one type may be used alone, or two or more types may be used in combination.

[0080] The polymerization initiator is preferably one that efficiently generates radicals when exposed to heat, and examples thereof include azo compounds such as 2,2'-azobisisobutyronitrile, dimethyl-2,2'-azobisisobutyrate, and 2,2'-azobis[2-(2-imidazolin-2-yl)propane], and organic peroxides such as 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and di(4-tert-butylcyclohexyl)peroxydicarbonate. The optimum temperature range for use depending on the decomposition temperature of these polymerization initiators is 50 to 150°C. One type of polymerization initiator may be used alone, or two or more types may be used in combination.

[0081] In the radical polymerization, a chain transfer agent can be used for the purpose of controlling the weight average molecular weight of the polymer compound (P). Examples of the chain transfer agent include butanethiol, octanethiol, decanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, cyclohexyl mercaptan, thiophenol, octyl thioglycolate, octyl 2-mercaptopropionate, octyl 3-mercaptopropionate, 2-ethylhexyl mercaptopropionate, 2-ethylhexyl thioglycolate, butyl-3-mercaptopropionate, mercaptopropyltrimethoxysilane, methyl-3-mercaptopropionate, 2,2-( Examples of the chain transfer agent include (ethylenedioxy)diethanethiol, ethanethiol, 4-methylbenzenethiol, octanoic acid 2-mercaptoethyl ester, 1,8-dimercapto-3,6-dioxaoctane, decane trithiol, dodecyl mercaptan, diphenyl sulfoxide, dibenzyl sulfide, 2,3-dimethylcapto-1-propanol, mercaptoethanol, thiosalicylic acid, thioglycerol, thioglycolic acid, 3-mercaptopropionic acid, thiomalic acid, mercaptoacetic acid, mercaptosuccinic acid, and 2-mercaptoethanesulfonic acid. One type of chain transfer agent may be used alone, or two or more types may be used in combination.

[0082] When a chain transfer agent is used, the amount of the chain transfer agent used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 15 parts by weight, and even more preferably 1 to 10 parts by weight, per 100 parts by weight of the total of the raw material monomers.

[0083] In the polymerization step, living radical polymerization may be employed. The living radical polymerization method is not particularly limited, and examples thereof include nitroxide-mediated polymerization (NMP) method, atom-transfer radical polymerization (ATRP) method, and reversible addition-fragmentation chain-transfer polymerization (RAFT) method.

[0084] For the living radical polymerization, a known chain transfer agent for living radical polymerization can be used. Examples of the chain transfer agent for living radical polymerization include TEMPO derivatives such as 2,2,6,6-tetramethyl-1-piperidinyloxy (hereinafter also referred to as "TEMPO"), 4-amino-TEMPO, 4-hydroxy-TEMPO, and 4-oxo-TEMPO, stable free radicals such as 4,4-dimethyl-3-oxazolinyloxy and derivatives thereof, 2,2,5,5-tetramethyl-1-pyrrolidinyloxy and derivatives thereof, phenyl-t-butyl nitroxide, and 2,2-di(4-t-octylphenyl)-1-picrylhydrazyl (DPPH), and compounds having a thiocarbonylthio structure (-S-C(=S)-), with compounds having a thiocarbonylthio structure being preferred.

[0085] Examples of compounds having a thiocarbonylthio structure include benzyl dithiobenzoate, 1-phenylethyl dithiobenzoate, cumyl dithiobenzoate, 1-acetoxylethyl dithiobenzoate, 1-(4-methoxyphenyl)ethyl dithiobenzoate, ethoxycarbonylmethyl dithiobenzoate, 2-(ethoxycarbonyl)prop-2-yl dithiobenzoate, 2-cyanoprop-2-yl dithiobenzoate, t-butyl dithiobenzoate, 2,4,4-trimethylpent-2-yl dithiobenzoate, benzyl dithioacetate, 1-phenylethyl dithioacetate, cumyl dithioacetate, 1-acetoxylethyl dithioacetate, 1-(4-methoxyphenyl)ethyl dithioacetate, ethoxycarbonylmethyl dithioacetate, 2-(ethoxycarbonyl)prop-2-yl dithioacetate, 2-methyl- ... -cyanoprop-2-yl, t-butyl dithioacetate, 2,4,4-trimethylpent-2-yl dithioacetate, 2-(4-chlorophenyl)prop-2-yl dithiobenzoate, 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentane, 2-cyano-2-[(dodecylsulfanylthiocarbonyl)sulfanyl]propane, S,S-dibenzyltrithiocarbonic acid, methyl 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoate, benzyl 4-methoxybenzodithioate, 2-cyanopropan-2-yl benzodithioate, 2-cyanopropan-2-yl benzodithioate, 4-cyano-4-[(thiobenzoyl)sulfanyl]pentanoic acid, 1-ethoxycarbonyl-1-phenylmethyl benzodithioate. The chain transfer agents for living radical polymerization may be used alone or in combination of two or more.

[0086] (Reprecipitation Purification Step) In the method for producing a polymer compound according to the embodiment, a reprecipitation purification step may be carried out before the recovery step, if necessary. A known method can be used for the reprecipitation purification. For example, the polymerization reaction solution after the polymerization step is added to a poor solvent to precipitate the polymer compound in the polymerization reaction solution, and the precipitate in the poor solvent is then filtered and dried. This results in a powder containing the polymer compound (P) from which the unreacted monomer and polymerization initiator contained in the polymerization reaction solution have been removed.

[0087] In the reprecipitation purification step, the wet powder obtained by filtering the precipitate in the poor solvent may be dispersed again in the poor solvent to obtain a polymer dispersion, which may then be filtered off. This procedure can further reduce impurities such as unreacted monomers and polymerization initiators remaining in the wet powder.

[0088] Examples of poor solvents include isopropyl ether, heptane, hexane, cyclohexane, toluene, and water. The poor solvent used in the reprecipitation purification may be one type or a mixed solvent of two or more types.

[0089] (Recovery Step) In the recovery step, the polymer compound (P) is extracted, separated, and recovered from the polymerization reaction product after the polymerization step by a liquid-liquid extraction method using the following solvents A and B. Solvent A: An organic solvent having HSP values ​​of δD = 10 to 20, 0 ≦ δP < 2, and δH = 0 to 4. The values ​​of each HSP term of solvent A are preferably δD = 12 to 19, more preferably 13 to 18. δP is preferably 0 to 1.5, more preferably 0 to 1.0. δH is preferably 0 to 3.5, more preferably 0 to 3.3. Solvent B: An organic solvent having HSP values ​​of δD = 10 to 20, δP = 5 to 15, and δH = 4 to 40. The values ​​of each HSP term of solvent B are preferably δD = 12 to 19, more preferably 13 to 18. δP is preferably 5.1 to 14, more preferably 5.3 to 13. δH is preferably 4 to 35, and more preferably 4 to 30.

[0090] The polymer compound (P) according to the embodiment has low solubility in solvent A and high solubility in solvent B. The mechanism by which the effects of the present invention are obtained is not clear, but it is presumed that by setting the HSP values ​​of solvent A and solvent B within the above-mentioned ranges, impurities such as unreacted monomers, polymerization initiators, and low-molecular-weight components, which are difficult to dissolve in solvent A alone, are mixed appropriately with solvent B, which is easy to dissolve in solvent A, and the HSP value of the entire solvent system changes, causing impurities such as low-molecular-weight components to be distributed into solvent A, enabling them to be extracted, separated, and recovered.

[0091] When the reprecipitation purification step is not performed, for example, solvent A and solvent B are added to the polymerization reaction solution after the polymerization step to perform liquid-liquid extraction. When the reprecipitation purification step is performed, for example, solvent B is added to the powder after the reprecipitation purification, and then solvent A is added to perform liquid-liquid extraction. After solvent A and solvent B are added to the polymerization reaction solution after the polymerization step to perform liquid-liquid extraction, reprecipitation purification may be performed.

[0092] Examples of solvent A include linear hydrocarbon solvents such as pentane, hexane, heptane, octane, nonane, and decane; aromatic hydrocarbon solvents such as benzene, toluene, o-xylene, and p-xylene; and cyclic hydrocarbon solvents such as cyclopentane, cyclohexane, and methylcyclohexane. Solvent A having a boiling point higher than a certain level stabilizes the extraction behavior and allows the desired molecular weight fraction to be achieved. Furthermore, solvent A having a boiling point lower than a certain level facilitates removal in downstream processes and is therefore easily removably from the final product. Therefore, preferred solvents are hexane, heptane, octane, benzene, toluene, o-xylene, p-xylene, cyclopentane, and cyclohexane. Solvent A may be used alone or in combination with two or more solvents. When two or more solvents are used in combination, they can be used in a mixing ratio such that the HSP of the resulting mixture satisfies δD = 10 to 20, 0≦δP < 2, and δH = 0 to 4.

[0093] Examples of solvent B include alcohol-based solvents such as methanol, ethanol, 1-butanol, 1-propanol, 2-propanol (hereinafter referred to as IPA), and propylene glycol monomethyl ether; aqueous solutions of the aforementioned solvents; ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester-based solvents such as propylene glycol monomethyl ether acetate and ethyl acetate; and ether-based solvents such as tetrahydrofuran and tetrahydropyran. Since solvent B must be easily separated from solvent A and easily removed in a subsequent process, methanol, ethanol, IPA, ethyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and tetrahydrofuran are preferred. As solvent B, one solvent may be used alone, or two or more solvents may be used in combination. When two or more solvents are used in combination, they can be used in a mixing ratio such that the HSP of the mixture has values ​​of δD = 10 to 20, δP = 5 to 15, and δH = 4 to 40. When an aqueous solution of an alcohol-based solvent is used as solvent B, the mass ratio of alcohol-based solvent / water is preferably 99 / 1 to 85 / 15, and more preferably 95 / 5 to 90 / 10.

[0094] In the recovery step, it is preferable to use a combination of solvents B1 and B2 as solvent B. The combined use of solvents B1 and B2 allows for more precise control of the distribution of each component. Solvent B1: An organic solvent having HSP values ​​of δD = 10 to 20, δP = 5 to 15, and δH = 11 to 40. Regarding the values ​​of each HSP term of solvent B1, δD is preferably 12 to 19, more preferably 13 to 18. δP is preferably 5.1 to 14, more preferably 5.3 to 13. δH is preferably 12 to 35, more preferably 13 to 30. When the values ​​of each HSP term of solvent B1 are within the above ranges, the viscosity of the solvent B phase containing the polymer compound (P) is reduced, ensuring process passability without concerns about pipe clogging, etc. Solvent B2: An organic solvent having HSP values ​​of δD = 10 to 20, δP = 5 to 15, and δH = 4 to 10. With regard to the values ​​of the HSP terms of solvent B2, δD is preferably 12 to 19, and more preferably 13 to 18. δP is preferably 5 to 13, and more preferably 5 to 9. δH is preferably 4 to 9, and more preferably 4 to 7.5. When the values ​​of the HSP terms of solvent B2 are within the above ranges, it is easy to obtain a polymer compound (P) from which low-molecular-weight components have been sufficiently removed, without a relatively large decrease in recovery rate.

[0095] Examples of solvent B1 include alcohol-based solvents from among the organic solvents exemplified for solvent B. Preferred examples of solvent B1 include methanol, ethanol, IPA, and propylene glycol monomethyl ether. As solvent B1, one type may be used alone, or two or more types may be used in combination. Preferred examples of solvent B2 include ketone-based solvents, ester-based solvents, and ether-based solvents from among the organic solvents exemplified for solvent B. Preferred examples of solvent B2 include ethyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, and tetrahydrofuran, and more preferred examples are ethyl acetate and methyl isobutyl ketone. Preferred examples of solvent B2 include one type alone, or two or more types may be used in combination.

[0096] When solvent B1 and solvent B2 are used as solvent B, the mass ratio (B1 / B2) of solvent B1 to solvent B2 is preferably 1 / 5 to 5 / 1, more preferably 1 / 4 to 4 / 1, and even more preferably 1 / 3 to 3 / 1. When the mass ratio (B1 / B2) is within the above range, a polymer compound (P) from which low-molecular-weight components have been sufficiently removed is likely to be obtained.

[0097] In the recovery step, solvent A and solvent B are added to the polymerization reaction product after the polymerization step, mixed, and then allowed to stand, resulting in continuous or intermittent distribution in the liquid depending on the specific gravity, polarity, etc. Solvent B tends to have a higher specific gravity than solvent A, and typically the solvent B phase is the lower phase and the solvent A phase is the upper phase. Note that, depending on the combination of solvent A and solvent B, the solvent A phase may be the lower phase and the solvent B phase may be the upper phase. In the recovery step, the polymer compound (P) is distributed into the solvent B phase, and low-molecular-weight components in the polymerization reaction product are distributed into the solvent A phase, and the solvent B phase is separated and recovered. This results in a polymer compound (P) with a narrow molecular weight distribution, from which low-molecular-weight components such as oligomers with low degrees of polymerization present in the polymerization reaction product have been separated.

[0098] In the recovery step, an extraction solvent containing the following solvent C in addition to solvent A and solvent B may be used. Adjusting the blending ratio of solvent C allows for more precise control of the distribution of each component. When solvent C is used, it is preferable that solvent B contains solvent B1. That is, the combination of solvent C and solvent B is preferably a combination of solvent C and solvent B1, or a combination of solvent C, solvent B1, and solvent B2. Solvent C: An organic solvent having HSP values ​​of δD = 10 to 20, 2 ≦ δP < 5, and δH = 3 to 10. Regarding the values ​​of each HSP term of solvent C, δD is preferably 12 to 19, more preferably 13 to 18. δP is preferably 3.1 to 4.5, more preferably 3.2 to 4.0. δH is preferably 3.1 to 9, more preferably 3.2 to 8.

[0099] The solubility of the polymerization reaction product in the solvents generally increases in the order of solvent A, solvent C, and solvent B. When solvent C is added, only low-molecular-weight components in the polymerization reaction product tend to be distributed into the solvent A phase. Therefore, by adding an appropriate amount of solvent C, it is possible to promote the distribution of low-molecular-weight components in the polymerization reaction product into the solvent A phase and the distribution of the polymer compound (P) into the solvent B phase.

[0100] Examples of solvent C include diisopropyl ether (hereinafter referred to as IPE), cyclopentyl methyl ether, n-propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, and isoamyl acetate. Since it is necessary for solvent C to be miscible with both solvents A and B while dissolving a highly polar polymer to some extent, IPE, cyclopentyl methyl ether, n-propyl acetate, isopropyl acetate, butyl acetate, and isobutyl acetate are preferred as solvent C. One type of solvent C may be used alone, or two or more types may be used in combination. One type of solvent C may be used alone, or two or more types may be used in combination.

[0101] As a specific operation, when liquid-liquid extraction is performed on the polymerization reaction solution after the polymerization step without performing the reprecipitation purification step, for example, solvent A and solvent B are added to the polymerization reaction solution after the polymerization step, mixed, and then allowed to stand. The order in which solvent A and solvent B are added is not particularly limited, and they may be added in the order of solvent A and solvent B, or solvent B and solvent A, or solvent A and solvent B may be added simultaneously. When liquid-liquid extraction is performed after performing the reprecipitation purification step, it is preferable, but not limited to, to dissolve the powder after the reprecipitation purification in solvent B, add solvent A, mix, and then allow to stand. When liquid-liquid extraction is repeated two or more times, solvent A is added to a solution in which the polymer compound (P) is dissolved in solvent B, mix, and then allow to stand.

[0102] The timing of adding solvent C is not particularly limited, and it may be added simultaneously with solvent A, or simultaneously with solvent B, or separately from solvents A and B. After standing, the solvent B phase into which the polymer compound (P) has been distributed is separated and recovered from the solvent A phase and the solvent B phase.

[0103] The amount of solvent A used is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, even more preferably 200 parts by mass or more, particularly preferably 300 parts by mass or more, and preferably 3500 parts by mass or less, more preferably 3000 parts by mass or less, even more preferably 2500 parts by mass or less, and particularly preferably 2000 parts by mass or less, relative to 100 parts by mass of the polymerization reaction product to be subjected to liquid-liquid extraction. When the amount of solvent A used is equal to or greater than the above-mentioned lower limit, the target molecular weight fraction can be achieved. When the amount of solvent A used is equal to or less than the above-mentioned upper limit, liquid-liquid extraction can be performed without polymer precipitation, and the target molecular weight fraction can be achieved. The lower and upper limits of the amount of solvent A used can be arbitrarily combined. For example, 50 to 3500 parts by mass is preferred, 100 to 3000 parts by mass is more preferred, 200 to 2500 parts by mass is more preferred, and 300 to 2000 parts by mass is particularly preferred.

[0104] The amount of solvent B used is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, even more preferably 150 parts by mass or more, particularly preferably 200 parts by mass or more, and preferably 2000 parts by mass or less, more preferably 1500 parts by mass or less, even more preferably 1250 parts by mass or less, and particularly preferably 1000 parts by mass or less, relative to 100 parts by mass of the solids content of the polymerization reaction product to be subjected to liquid-liquid extraction. When the amount of solvent B used is equal to or greater than the above-mentioned lower limit, the polymer can be dissolved in the solvent and subjected to liquid-liquid extraction. When the amount of solvent B used is equal to or less than the above-mentioned upper limit, the target molecular weight fraction can be achieved with high yield. The lower and upper limits of the amount of solvent B used can be arbitrarily combined; for example, 50 to 2000 parts by mass is preferred, 100 to 1500 parts by mass is more preferred, 150 to 1250 parts by mass is more preferred, and 200 to 1000 parts by mass is particularly preferred.

[0105] The amount of solvent C used is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, even more preferably 150 parts by mass or more, particularly preferably 200 parts by mass or more, and is preferably 2000 parts by mass or less, more preferably 1500 parts by mass or less, even more preferably 1250 parts by mass or less, particularly preferably 1000 parts by mass or less, per 100 parts by mass of the solids content of the polymerization reaction product to be subjected to liquid-liquid extraction. When the amount of solvent C used is equal to or greater than the lower limit, low-molecular-weight components are easily distributed into the solvent A phase, and the efficiency of removal from the polymer compound (P) is increased. When the amount of solvent C used is equal to or less than the upper limit, the polymer compound (P) is less likely to be distributed into the solvent A phase, and the recovery efficiency of the polymer compound (P) is improved. The lower and upper limits of the amount of solvent C used can be arbitrarily combined, and are, for example, preferably 50 to 2000 parts by mass, more preferably 100 to 1500 parts by mass, even more preferably 150 to 1250 parts by mass, and particularly preferably 200 to 1000 parts by mass.

[0106] In the method for producing a polymer compound according to the embodiment, the extraction and separation operation of the polymer compound (P) by liquid-liquid extraction may be repeated two or more times in the recovery step. By repeating the extraction and separation operation, a polymer compound (P) having a narrower molecular weight distribution and from which low-molecular-weight components have been more efficiently removed can be obtained. The number of times the extraction and separation operation is repeated is not particularly limited, and can be, for example, 0 to 1 time, 1 to 2 times, 2 to 3 times, or 3 to 4 times.

[0107] In the recovery step, low-molecular-weight components present in the polymerization reaction product after the polymerization step are separated, i.e., low-polymerization oligomers that constitute a portion of the low-molecular-weight side of the molecular weight distribution of the unpurified polymer after polymerization are separated, resulting in a narrower molecular weight distribution of the polymer compound (P) than the unpurified polymer. When the molecular weight dispersity (Mw / Mn) of the polymer compound (P) after the recovery step (after purification) is Pa and the molecular weight dispersity (Mw / Mn) of the unpurified polymer after the polymerization reaction (the polymerization reaction product before the reprecipitation purification step and recovery step) is Pb, the value expressed by Pa / Pb is preferably 0.90 or less, and may be 0.89 or less, or 0.85 or less. The lower limit of Pa / Pb is not particularly limited and may be 0.30 or more, 0.40 or more, or 0.50 or more. The value expressed by Pa / Pb is preferably 0.30 to 0.90, and may be 0.40 to 0.89, or 0.50 to 0.85.

[0108] (Solvent Replacement Step) A solvent D having a boiling point higher than that of solvent B is added to the solution of polymer compound (P) dissolved in solvent B recovered in the recovery step, and solvent B is distilled off under reduced pressure to obtain a solution of polymer compound (P) dissolved in solvent D. This allows the type and concentration of the solvent in which the recovered polymer compound (P) is dissolved to be appropriately adjusted depending on the application.

[0109] The solvent D can be appropriately selected depending on the application from those capable of dissolving the polymer compound (P), and examples thereof include PGMEA, propylene glycol monomethyl ether, gamma butyrolactone, and ethyl lactate. As the solvent D, one type may be used alone, or two or more types may be used in combination.

[0110] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following descriptions.

[0111] The following measurement methods were used: <Measurement of Weight Average Molecular Weight> The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of a polymer were determined in terms of polystyrene by gel permeation chromatography under the following conditions (GPC conditions).

[0112] [GPC conditions] Apparatus: Tosoh high-speed GPC apparatus HLC-8320GPC (trade name), manufactured by Tosoh Corporation; Separation column: Three Shodex GPC K-805L (trade name), manufactured by Showa Denko K.K., connected in series; Measurement temperature: 40°C; Eluent: Tetrahydrofuran (THF); Sample: A solution prepared by dissolving approximately 20 mg of polymer in 5 mL of THF and filtering through a 0.5 μm membrane filter; Flow rate: 1 mL / min; Injection volume: 0.1 mL; Detector: Differential refractometer. Calibration curve I: A solution prepared by dissolving approximately 20 mg of standard polystyrene in 5 mL of THF and filtering through a 0.5 μm membrane filter was injected into the separation column under the above conditions, and the relationship between elution time and molecular weight was determined. The standard polystyrenes used were the following standard polystyrenes manufactured by Tosoh Corporation (all trade names): F-80 (Mw = 706,000), F-20 (Mw = 190,000), F-4 (Mw = 37,900), F-1 (Mw = 10,200), A-2500 (Mw = 2,630), A-500 (Mixture of Mw = 682, 578, 474, 370, 260).

[0113] In the following examples and comparative examples, monomers represented by the following formulae (m1-1) to (m1-4), (m2-1), (m3-1), (m3-2), (m4-1), and (m5-1) were used.

[0114]

[0115]

[0116]

[0117]

[0118] In the following examples and comparative examples, the following chain transfer agents E1 and E2 were used: E1: 1-butanethiol E2: 2-cyanopropan-2-yl benzodithioate

[0119] In the following Examples and Comparative Examples, the following solvents were used in the polymer recovery process: (Solvent A): δD = 10-20, 0≦δP<2, δH = 0-4 Heptane (δD = 15.3, δP = 0, δH = 0) Octane (δD = 15.5, δP = 0, δH = 0) Toluene (δD = 18.0, δP = 1.4, δH = 2.0) HEP: Toluene = 43 / 57 (v / v) (δD = 16.8, δP = 0.8, δH = 1.1) (Solvent B): δD = 10-20, 5≦δP≦15, δH = 4-40 Methanol (δD = 14.7, δP = 12.3, δH = 22.3) Ethanol (δD = 15.8, δP = 8.8, δH = 19.4) IPA / water = 90 / 10 (v / v) (δD = 16.0, δP = 7.1, δH = 19.0) Ethyl acetate (δD = 15.8, δP = 5.3, δH = 7.2) PGMEA (δD = 15.6, δP = 5.6, δH = 9.8) PGME (δD=17.4, δP=5.3, δH=11.5) Acetone (δD=15.5, δP=10.4, δH=7) MEK (δD=16, δP=9, δH=5.1) MIBK (δD=15.3, δP=6.1, δH=4.1) THF (δD=16.8, δP=5.7, δH=8) MeOH:EA = 29 / 71 (v / v) (δD = 15.5, δP = 7.3, δH = 11.6) MeOH:PGMEA = 33 / 67 (v / v) (δD = 15.3, δP = 7.8, δH = 13.9) (Solvent C); δD = 10-20, 2 ≦ δP < 5, δH = 3-10 IPE (δD = 15.1, δP = 3.2, δH = 3.2) n-Propyl acetate (δD = 17.3, δP = 4.3, δH = 7.6) Isopropyl acetate (δD = 17.3, δP = 4.5, δH = 8.2) n-Butyl acetate (δD = 15.8, δP = 3.7, δH = 6.3) (Other solvents) Gamma butyrolactone (hereinafter referred to as GBL) (δD = 17.3, δP = 16.6, δH = 7.4) Acetonitrile (δD = 17.3, δP = 18.0, δH = 6.1)

[0120] Example 1: A flask equipped with a nitrogen inlet, a stirrer, a condenser, and a thermometer was charged with 136.0 parts by mass of PGMEA under a nitrogen atmosphere, and the temperature of the water bath was raised to 85°C while stirring. Subsequently, the following mixture 1 was added dropwise to the flask from a dropping funnel over 5 hours, and the temperature was maintained at 85°C for an additional 3 hours to obtain a polymerization reaction solution (polymer a). (Composition of mixture 1): 65.34 parts by mass (50 mol%) of monomer (m3-1), 93.32 parts by mass (50 mol%) of monomer (m1-1), 158.66 parts by mass of PGMEA solvent, and 30.36 parts by mass of polymerization initiator: dimethyl-2,2'-azobisisobutyrate (V601 (product name), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). The resulting polymerization reaction solution was mixed with 12 times the mass of heptane, precipitated, and then solid-liquid separated and dried under reduced pressure to obtain 155 parts by mass of a white solid. 100 parts by mass of the resulting white solid was dissolved in 700 parts by mass of solvent B (methanol:ethyl acetate = 29:71 (v / v)), and 600 parts by mass of solvent A (heptane) was added and stirred. After stirring was stopped, the separated lower phase liquid was recovered. PGMEA was added to the recovered lower phase liquid, and the low-boiling point solvent was removed by distillation under reduced pressure to perform solvent replacement, yielding a PGMEA solution of the polymer compound. The weight average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) determined by analyzing this solution by gel permeation chromatography are shown in Table 2.

[0121] Examples 2 to 7 A recovery step was carried out using 100 parts by mass of the white solid obtained in the same manner as in Example 1, using parts by mass of solvent A, solvent B, or solvent C shown in Table 2, and a solvent substitution step was carried out to obtain a PGMEA solution of the polymer compound. The weight average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) determined by analyzing this solution by gel permeation chromatography are shown in Table 2.

[0122] Example 8 PGMEA was added to the polymerization reaction solution obtained in the same manner as in Example 1 to prepare a 20% PGMEA solution. 200 parts by mass of methanol (solvent B) and 600 parts by mass of heptane (solvent A) were added to this 20% PGMEA solution and stirred. After stirring was stopped, the separated lower phase liquid was recovered. 200 parts by mass of methanol and 600 parts by mass of heptane were added to the recovered lower phase liquid and stirred. The procedure of recovering the separated lower phase liquid after stirring was repeated. Further PGMEA was added to the recovered lower phase liquid, and the low-boiling point solvent was removed by distillation under reduced pressure to perform solvent replacement, yielding a PGMEA solution of a polymer compound. The weight-average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) determined by analyzing this solution by gel permeation chromatography are shown in Table 2.

[0123] Examples 9 to 29 Polymerization reaction solutions (polymers b to m) were obtained in the same manner as in Example 1, except that the monomers shown in Table 1 were used, and the resulting white solid was subjected to solid-liquid separation and dried under reduced pressure. 100 parts by mass of the resulting white solid was subjected to a recovery step using parts by mass of solvent A, solvent B, or solvent C shown in Tables 2 to 4, and a solvent substitution step was carried out to obtain PGMEA solutions of polymer compounds. The weight average molecular weights (Mw) and molecular weight dispersities (Mw / Mn) determined by analyzing these solutions by gel permeation chromatography are shown in Tables 2 to 4.

[0124] Comparative Examples 1 to 6 A recovery step was carried out using 100 parts by mass of the white solid obtained in the same manner as in Example 1, using parts by mass of Solvent A, Solvent B, Solvent C, or other solvents shown in Table 5, followed by a solvent substitution step to obtain a PGMEA solution of the polymer compound. The weight average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) determined by analyzing this solution by gel permeation chromatography are shown in Table 5.

[0125] [Comparative Examples 7 to 10] 100 parts by mass of the white solid obtained in the same manner as in Example 1 was mixed with the solvents listed in Table 6, and the mixture was stirred to form a reslurry, followed by solid-liquid separation. PGMEA was added to the resulting wet powder and redissolved, and the low-boiling point solvent was then removed by distillation under reduced pressure to perform solvent replacement, yielding a PGMEA solution of the polymer compound. The weight-average molecular weight (Mw) and molecular weight dispersity (Mw / Mn) determined by analyzing this solution using gel permeation chromatography are shown in Table 6. In Comparative Examples 8, 9, and 10, the wet powder fused after solid-liquid separation, making it impossible to stably recover it as a wet powder, and therefore the solvent replacement step was discontinued. Table 6 indicates whether or not the product could be obtained in powder form after solid-liquid separation.

[0126]

[0127] Tables 2 to 5 show values ​​expressed by the following formula (1): Pa / Pb Formula (1) Pa: molecular weight dispersity (Mw / Mn) of the polymer compound after purification (after the recovery step) Pb: molecular weight dispersity (Mw / Mn) of the unpurified polymer after the polymerization reaction

[0128]

[0129]

[0130]

[0131]

[0132] The abbreviations in Tables 2 to 5 have the following meanings: HEP: heptane, OCT: octane, Tol: toluene, IPE: diisopropyl ether, MeOH: methanol, EtOH: ethanol, IPA: isopropyl alcohol, Pw: pure water, EA: ethyl acetate, MEK: methyl ethyl ketone, MIBK: methyl isobutyl ketone, THF: tetrahydrofuran, PnAc: n-propyl acetate, PiAc: isopropyl acetate, PGME: propylene glycol-1-monomethyl ether, PGMEA: propylene glycol-1-monomethyl ether-2-acetate, GBL: γ-butyrolactone, AeN: acetonitrile, BA: n-butyl acetate

[0133]

[0134] The polymer compounds of Examples 1 to 29 have a value represented by formula (1) of 0.9 or less, have a sufficiently narrow molecular weight distribution, and have more uniform solubility in a developer, making them useful as photoresist polymers. On the other hand, the polymer compounds of Comparative Examples 1 to 10 have a value represented by formula (1) of greater than 0.9, and have variable solubility in a developer, resulting in poor pattern shapes.

Claims

1. A method for producing a polymer compound, comprising: a polymerization step of polymerizing a monomer composition containing a monomer, a polymerization solvent, and a polymerization initiator to obtain a polymerization reaction product containing a polymer compound; and a recovery step of extracting, separating, and recovering the polymer compound using multiple solvents, wherein the recovery step is a liquid-liquid extraction method using solvent A and solvent B, wherein solvent A is an organic solvent having the Hansen Solubility Parameter (HSP) values ​​of δD = 10-20, 0 < δP < 2, and δH = 0-4, expressed in three terms of δD, δP, and δH, and solvent B is an organic solvent having the HSP values ​​of δD = 10-20, δP = 5-15, and δH = 4-40, and wherein the recovery step distributes the polymer compound into the solvent B phase, distributes low molecular weight components in the polymerization reaction product into the solvent A phase, and separates and recovers the solvent B phase.

2. The method for producing a polymer compound according to claim 1, wherein in the recovery step, a combination of solvent B1 and solvent B2 is used as solvent B, solvent B1 is an organic solvent having HSP values ​​of δD=10-20, δP=5-15, and δH=11-40, and solvent B2 is an organic solvent having HSP values ​​of δD=10-20, δP=5-15, and δH=4-10.

3. The method for producing a polymer compound according to claim 1, wherein a solvent C is further used in the recovery step, and the solvent C is an organic solvent having HSP values ​​of δD = 10 to 20, 2≦δP < 5, and δH = 3 to 10.

4. The method for producing a polymer compound according to claim 1, further comprising a reprecipitation purification step of subjecting the polymerization reaction product or the polymer compound to reprecipitation purification before or after the recovery step.

5. The method for producing a polymer compound according to claim 1, further comprising a solvent substitution step of adding solvent D having a boiling point higher than that of solvent B to solvent B in which the polymer compound has been dissolved after the recovery step, and partially evaporating the solvent from the solution containing the polymer compound under reduced pressure to obtain a solution of the polymer compound containing solvent D.

6. The method for producing a polymer compound according to claim 1, wherein the extraction and separation operation of the polymer compound by the liquid-liquid extraction method is repeated two or more times in the recovery step.

7. The method for producing a polymer compound according to claim 1, wherein the polymer compound has a phenolic hydroxyl group.

8. The method for producing a polymer compound according to claim 1, wherein the polymer compound has an acid-dissociable group.

9. The method for producing a polymer compound according to claim 1, wherein the polymer compound is used as a photoresist polymer.

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