Polymer production method and polymer

Abstract

The present invention provides a polymer production method comprising: (1) a step in which a monomer starting material including a prescribed monomer is polymerized by living radical polymerization using a radical initiator and a RAFT agent to obtain a polymer P-1 having a terminal structure that includes, at a terminal of the main chain thereof, a sulfur atom derived from the RAFT agent; (2) a step in which, subsequent to step (1), a radical generator and a thiol compound are added to a solution including the polymer P-1 and the same is heated to remove the terminal structure from the main chain of the polymer P-1; and (3) a step in which, subsequent to step (2), the solution including the polymer P-1 with the terminal structure removed therefrom is mixed with a poor solvent to precipitate the polymer as a solid and purify the same.

Description

Polymer manufacturing method and polymer

[0001] The present invention relates to a method for producing a polymer and the polymer.

[0002] As LSIs become more highly integrated and faster, miniaturization is progressing rapidly. The most advanced miniaturization technology is ArF immersion lithography, which involves inserting a liquid such as water between the projection lens and the substrate for exposure, and the application of multiple exposures (multi-patterning) of ArF lithography and extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm is also progressing.

[0003] The base polymer of a chemically amplified resist composition used in EUV lithography is typically one that uses a vinylphenol-based repeating unit such as 4-hydroxystyrene as its structural unit for the purpose of controlling resist sensitivity and dissolution of the resist film. Furthermore, base polymers containing an acid generator unit have an acid-generating moiety in the polymer side chain, which can suppress acid diffusion and enable the formation of high-resolution patterns, making them extremely useful in EUV lithography. Examples of polymers for such resist compositions that have been investigated include those described in Patent Documents 1 to 4.

[0004] The mainstream method for producing a polymer for a base polymer for an EUV resist composition is random polymerization using a radical initiator, which has been commonly used in the production of base polymers for ArF resist compositions. In random polymerization, a drop polymerization method is particularly preferred, in which the radical initiator and the monomer are prepared as a single solution or as separate solutions, and then dropped into a heated solution. A highly accurate production method has been established, covering everything from the polymerization reaction to a method for obtaining a highly pure polymer solution (Patent Document 5).

[0005] With the recent development of EUV lithography, there are increasingly stringent demands for improved performance from resist materials, such as high resolution, low roughness, and high etching selectivity between exposed and unexposed patterns. To meet these performance requirements, it is necessary to narrow the molecular weight and polydispersity of the polymer as much as possible and form a resist pattern using a composition containing a homogeneous base polymer with little variation. Similarly, for base polymers containing acid generator units, which have been confirmed to be useful in EUV lithography, further improvements in resist performance are expected by using polymers with uniform molecular weight and polydispersity.

[0006] Broadly speaking, there are two approaches commonly used to narrow the polydispersity of polymers: one is a purification method in which polymers with a low degree of polymerization and unreacted monomers are removed from polymers obtained by random polymerization through a reprecipitation process, and the other is a method in which the degree of polymerization is controlled uniformly during the polymerization reaction to obtain a narrow polydispersity polymer.

[0007] A purification method in which components with a low degree of polymerization and unreacted monomers contained in a polymer obtained by random polymerization are removed by reprecipitation or liquid-liquid fractionation is a commonly used method. However, in the case of a base polymer containing an acid generator unit, the usefulness of which has been confirmed in EUV lithography, the acid-generating monomer has a salt structure consisting of a pair of an organic acid anion and an organic cation, and therefore generally has low solubility in a solvent, making it extremely difficult to remove the polymer with a low degree of polymerization and the unreacted acid generator monomer, and therefore there is a limit to how narrowly dispersed the polymer can be achieved by strengthening the purification method.

[0008] As a method for obtaining a polymer with a narrow dispersity as a base polymer for a resist composition through a reaction process, living radical polymerization, particularly a method using a reversible addition-fragmentation chain transfer agent (hereinafter also referred to as a RAFT agent), has been proposed (Patent Documents 6, 7, and 8).

[0009] The researchers also proposed methods for narrowing the dispersion of polymers used as base polymers in resist compositions and for removing sulfur atoms from dithioester terminals, trithiocarbonate terminals, and other residues derived from RAFT agents generated during the living radical polymerization process. However, there were several issues to be resolved before these methods could be used as mass production techniques for base polymers.

[0010] As an example of a problem with living radical polymerization using a RAFT agent according to the prior art, Example 4 described in Patent Document 7 shows that the terminal conversion rate after the step of adding thiol to remove polymer terminal groups containing sulfur atoms derived from the RAFT agent is as low as 63%. Even if the polymer is purified by reprecipitation, terminal groups containing sulfur atoms, which are considered unstable, remain, raising concerns about coloration and decomposition over time. None of the examples in Patent Document 7 achieve a terminal removal rate of more than 90%, making it difficult to describe the method as an excellent one. Furthermore, Example 1 of Patent Document 8 adds a thermal radical generator in an amount 10 times the amount of the RAFT agent used during polymerization to reduce thiocarbonylthio terminal groups derived from the RAFT agent, but none of the examples demonstrate complete removal of terminal groups containing sulfur atoms.

[0011] Another issue is the difficulty in applying conventional techniques to the production of base polymers for advanced EUV lithography. Specifically, there is a problem with concentration during living radical polymerization using a RAFT agent. Taking Example 4 of Patent Document 7 as an example again, the concentration of a solution in which all monomers are dissolved in 1-methoxy-2-propanol, the polymerization solvent, at the start of polymerization is 77% by mass. Even at the end of the polymerization when all the initiator solution has been added, the reaction system remains at a very high concentration of approximately 60% by mass. This is presumably done for the purpose of increasing the concentration of the reaction system in order to polymerize and consume the monomers as efficiently as possible in the shortest possible time. However, units having an acid generator structure with a salt structure, as mentioned above, may have poor solubility in some solvents commonly used in polymerization. Even if a solvent with excellent solubility is selected, problems are expected to occur when preparing a solution containing a monomer that generates acid at a high concentration exceeding 60% by mass.

[0012] JP 2011-070033 A JP 2012-048075 A WO 2013 / 111667 JP 2011-033839 A JP 2020-070399 A JP 2005-156725 A WO 2019 / 189276 WO 2012 / 165473

[0013] Narrowing the polydispersity of polymers is expected to be essential for designing base polymers for resist compositions that meet the demands for improved performance, such as high resolution, low roughness, and high etching selectivity. However, with respect to base polymers for resist compositions that contain acid generator units, there are limitations to the extent to which acid generator monomers with low solvent solubility and polymers with low degrees of polymerization can be removed by purification. On the other hand, an excellent production method has not yet been established that combines narrowing the polydispersity through living radical polymerization using a RAFT agent with an appropriate method for removing sulfur-containing terminal groups with the aim of improving stability over time.

[0014] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a polymer containing an acid generator unit obtained by living radical polymerization using a RAFT agent, wherein the polymer has a small amount of residual monomer, is narrowly dispersed, and has a high purity, by which terminal groups containing sulfur atoms derived from the RAFT agent are removed with high efficiency.

[0015] As a result of extensive investigations to achieve the above object, the present inventors have found that, by going through the steps (1) to (13) described below, living radical polymerization proceeds with high efficiency, which was insufficient in the living radical polymerization and terminal treatment methods using a RAFT agent proposed in the prior art, terminal groups derived from the RAFT agent containing sulfur atoms can be removed simply and with high efficiency, and a highly pure polymer can be obtained by further purifying the polymer from which the terminal groups have been removed, thereby completing the present invention.

[0016] That is, the present invention provides the following polymer production method and polymer: 1. A method for producing a polymer comprising a repeating unit (A) derived from a monomer (A) having a structure that generates acid upon exposure, represented by any one of the following formulae (A1) to (A6), a repeating unit (B) derived from a monomer (B) having a phenolic hydroxy group, represented by the following formula (B1), and a repeating unit (C) derived from a monomer (C) that decomposes under the action of an acid, the method comprising: (1) polymerizing raw material monomers including the monomer (A), the monomer (B), and the monomer (C) in a solution by living radical polymerization using a radical initiator and a reversible addition-fragmentation chain transfer agent (RAFT agent) to obtain a polymer P-1 having, at an end of its main chain, a terminal structure selected from a structure derived from the RAFT agent and represented by the following formula (X-1) and a structure represented by the following formula (X-2); (2) after step (1), adding a radical generator and a thiol compound to a solution containing the polymer P-1 and heating the solution to remove the terminal structure from the main chain of the polymer P-1, thereby obtaining a polymer P; (3) after step (2), mixing the solution containing the polymer P with a poor solvent to precipitate the polymer P as a solid and purify it. (In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 , R 2 and R 3 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 1 and R 2 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 1 are each independently a single bond or a phenylene group. 2 are each independently *-C(=O)-O-X 21 -, *-C(=O)-NH-X 21 - or *-O-X 21 - is. X 21X is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain at least one selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. 3 each independently represents a single bond, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, or *-C(=O)-O-X 31 - is. X 31 X is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. 4 are each independently a single bond, -X 41 -C(=O)-O- or -O-X 41 -O-C(=O)-. X 41 X is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, *-C(=O)-O-X 51 -, *-C(=O)-N(H)-X 51 - or *-O-X 51 - is. X 51 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. * represents a bond to a carbon atom in the main chain. X 6 represents a single bond, a methylene group, an ethylene group, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, *-C(=O)-O-X 61-, *-C(=O)-N(H)-X 61 - or *-O-X 61 - is. X 61 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. * represents a bond to a carbon atom in the main chain. L A1 Rf each independently represents a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond, or a carbamate bond. 1 and Rf 2 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. 5 and Rf 6 and cannot simultaneously become hydrogen atoms. - are each independently a non-nucleophilic counter ion. + are each independently an onium cation; a and b are each independently 0, 1, 2, or 3. (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 11 is a saturated hydrocarbyl group having 1 to 6 carbon atoms which may contain at least one selected from a halogen atom, an ether bond, and a carbonyl group. B1 is a single bond, a carbonyloxy group, or an amide group. B2is a single bond, or an alkanediyl group having 1 to 7 carbon atoms which may contain at least one bond selected from an ether bond and a carbonyl group. c1 is an integer which satisfies 0≦c1≦5+2(c3)−c2. c2 is 1, 2, 3, 4, or 5. c3 is 0, 1, or 2. (In the formula, R X1 and R X2 are each independently a saturated hydrocarbyl group having 2 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, which may contain a heteroatom. The dashed lines represent bonds to carbon atoms in the polymer main chain. 2. The method for producing a polymer according to 1, wherein in step (1), the amounts of monomer (A), monomer (B), and monomer (C) remaining in the polymer P-1 solution obtained are less than 2 mass%, less than 1 mass%, and less than 2 mass%, respectively, relative to the total mass of all the charged monomers. 3. The method for producing a polymer according to 1 or 2, wherein the thiol compound used in step (2) is a compound represented by the following formula (SH-1) or (SH-2): (In the formula, R SH1 is a hydrocarbylene group having 1 to 3 carbon atoms. SH2 R is an aliphatic hydrocarbyl group having 4 to 8 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, or an aryl group having 6 to 18 carbon atoms, which may contain a heteroatom. SH3is a saturated hydrocarbyl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, or an aryl group having 6 to 18 carbon atoms, which may contain a heteroatom. 4. A method for producing a polymer according to any of 1 to 3, wherein in step (2), the amounts of monomer (A), monomer (B), and monomer (C) remaining in the polymer solution obtained are less than 0.05 mass%, less than 0.01 mass%, and less than 0.05 mass%, respectively, relative to the total mass of all the charged monomers. 5. A method for producing a polymer according to any of 1 to 4, wherein the molar ratios of structures selected from the structure represented by formula (X-1) and the structure represented by formula (X-2) contained in the polymer are each less than 1%. 6. A method for producing a polymer according to any of 1 to 5, wherein in step (1), monomer (A), monomer (B), monomer (C), a radical initiator, and a RAFT agent are mixed to form a single solution, and then heated to carry out living radical polymerization. 7. 7. A method for producing a polymer according to any one of 1 to 6, wherein in step (1), the monomer (A), the monomer (B), the monomer (C) and the radical initiator are prepared as one or separate solutions, and the solutions are added to a preheated RAFT agent solution to carry out living radical polymerization. 8. A method for producing a polymer according to any one of 1 to 7, wherein in step (1), the amount of radical initiator charged is 0.5 to 5 mol and the amount of RAFT agent charged is 0.5 to 20 mol, relative to 100 mol of the total amount of monomers charged. 9. A method for producing a polymer solution, comprising dissolving the polymer obtained by any one of methods 1 to 8 in a solvent containing at least propylene glycol monomethyl ether acetate, and then filtering the resulting solution using a filter. 10. A polymer comprising: a repeating unit (A) derived from a monomer (A) having a structure that generates acid upon exposure, the repeating unit (A) being represented by any of the following formulas (A1) to (A6); a repeating unit (B) derived from a monomer (B) having a phenolic hydroxy group, the repeating unit (B) being represented by the following formula (B1); and a repeating unit (C) derived from a monomer (C) that decomposes under the action of an acid, wherein the residual amount of the monomer (A) contained in the polymer is 0.05% by mass or less, the residual amount of the monomer (B) is 0.01% by mass or less, and the residual amount of the monomer (C) that decomposes under the action of an acid is 0.05% by mass or less, and the polydispersity is 1.50 or less. (In the formula, R Aare each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 , R 2 and R 3 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 1 and R 2 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 1 are each independently a single bond or a phenylene group. 2 are each independently *-C(=O)-O-X 21 -, *-C(=O)-NH-X 21 - or *-O-X 21 - is. X 21 X is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain at least one selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. 3 each independently represents a single bond, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, or *-C(=O)-O-X 31 - is. X 31 X is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. 4 are each independently a single bond, -X 41 -C(=O)-O- or -O-X 41 -O-C(=O)-. X 41 X is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom. 5represents a single bond, a methylene group, an ethylene group, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, *-C(=O)-O-X 51 -, *-C(=O)-N(H)-X 51 - or *-O-X 51 - is. X 51 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. * represents a bond to a carbon atom in the main chain. X 6 represents a single bond, a methylene group, an ethylene group, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, *-C(=O)-O-X 61 -, *-C(=O)-N(H)-X 61 - or *-O-X 61 - is. X 61 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. * represents a bond to a carbon atom in the main chain. L A1 Rf each independently represents a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond, or a carbamate bond. 1 and Rf 2 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. 5 and Rf 6and cannot simultaneously become hydrogen atoms. - are each independently a non-nucleophilic counter ion. + are each independently an onium cation; a and b are each independently 0, 1, 2, or 3. (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 11 is a saturated hydrocarbyl group having 1 to 6 carbon atoms which may contain at least one selected from a halogen atom, an ether bond, and a carbonyl group. B1 is a single bond, a carbonyloxy group, or an amide group. B2 is a single bond, or an alkanediyl group having 1 to 7 carbon atoms which may contain at least one bond selected from an ether bond and a carbonyl group. c1 is an integer which satisfies 0≦c1≦5+2(c3)−c2. c2 is 1, 2, 3, 4, or 5. c3 is 0, 1, or 2.

[0017] The polymer production method of the present invention makes it possible to obtain a polymer having a small amount of residual monomer and a uniform molecular weight and dispersity, which is particularly suitable for EB lithography and EUV lithography. A resist composition using the polymer as a base polymer is expected to exhibit improved performance, such as high resolution, low roughness, and high etching selectivity.

[0018] 1 shows the results of HPLC analysis after completion of each step in Examples 1-3.

[0019] The present invention will be described in detail below. In the following chemical formulae, some enantiomers or diastereomers may exist due to their chemical structures, but unless otherwise specified, each chemical formula represents all of these stereoisomers. These stereoisomers may be used alone or as a mixture.

[0020] The method for producing a polymer of the present invention is a method for producing a polymer (hereinafter also referred to as polymer P) containing a repeating unit (A) derived from a monomer (A) having a structure that generates an acid upon exposure, a repeating unit (B) derived from a monomer (B) having a phenolic hydroxy group, and a repeating unit (C) derived from a monomer (C) that decomposes under the action of an acid, and includes the following steps (1) to (3): (1) a step of polymerizing raw material monomers including monomer (A), monomer (B), and monomer (C) in a solution by living radical polymerization using a radical initiator and a reversible addition-fragmentation chain transfer agent (RAFT agent) to obtain a polymer P-1 having, at an end of its main chain, a terminal structure selected from the structure represented by formula (X-1) and the structure represented by formula (X-2) derived from the RAFT agent; (2) after step (1), a step of adding a radical generator and a thiol compound to a solution containing polymer P-1 and heating the solution to remove the terminal structure from the main chain of polymer P-1 to obtain polymer P; and (3) after step (2), a step of mixing the solution containing polymer P with a poor solvent to precipitate polymer P as a solid and purify it.

[0021] Living radical polymerization using a radical initiator and a RAFT agent can be carried out with reference to methods described in Japanese Patent No. 3639859, JP 2006-002096 A, Patent Documents 6 and 7, etc. However, as mentioned above, all of the production methods proposed in the prior art have had many problems, particularly when the aim is to obtain a polymer composed of repeating units that generate acid upon exposure with high efficiency and high purity. The inventors have now made extensive studies and have found that suitable conditions for each of steps (1) to (3) and combinations of these steps are particularly effective, and therefore steps (1) to (3) will be described in detail below in this order.

[0022] [Step (1)] Step (1) is a step of polymerizing raw material monomers including monomer (A), monomer (B), and monomer (C) in a solution by living radical polymerization using a radical initiator and a reversible addition-fragmentation chain transfer agent (RAFT agent) to obtain a polymer P-1 having, at the end of its main chain, a terminal structure selected from the structure represented by formula (X-1) and the structure represented by formula (X-2) derived from the RAFT agent.

[0023] <Monomer> The monomer (A) is represented by any one of formulas (A1) to (A6).

[0024] In formulas (A1) to (A6), R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0025] In formulas (A1) and (A2), R 1 , R 2 and R 3 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; saturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; unsaturated cyclic aliphatic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and thienyl; and aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl. Of these, aryl groups are preferred. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, or a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom may be present between carbon atoms of the hydrocarbyl group, resulting in the hydrocarbyl group containing a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. 1 and R 2may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0026] In formulas (A1) and (A2), X 1 are each independently a single bond or a phenylene group.

[0027] In formulas (A1) and (A2), X 2 are each independently *-C(=O)-O-X 21 -, *-C(=O)-NH-X 21 - or *-O-X 21 - is. X 21 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain at least one selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group.

[0028] In formulas (A3) and (A4), X 3 each independently represents a single bond, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, or *-C(=O)-O-X 31 - is. X 31 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring.

[0029] In formulas (A3) and (A4), X 4 are each independently a single bond, -X 41 -C(=O)-O- or -O-X 41 -O-C(=O)-. X 41 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom.

[0030] In formula (A5), X 5represents a single bond, a methylene group, an ethylene group, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, *-C(=O)-O-X 51 -, *-C(=O)-N(H)-X 51 - or *-O-X 51 - is. X 51 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. * represents a bond to a carbon atom in the main chain.

[0031] In formula (A6), X 6 represents a single bond, a methylene group, an ethylene group, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, *-C(=O)-O-X 61 -, *-C(=O)-N(H)-X 61 - or *-O-X 61 - is. X 61 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. * represents a bond to a carbon atom in the main chain.

[0032] In formulas (A3) and (A4), L A1 are each independently a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond, or a carbamate bond.

[0033] In formulae (A3) and (A4), a and b each independently represent 0, 1, 2, or 3. a is preferably 0 or 1, and b is preferably 1.

[0034] In formula (A3), Rf 1 and Rf 2are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms.

[0035] In formula (A4), Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. 5 and Rf 6 cannot simultaneously become a hydrogen atom.

[0036] Specific examples of the cation of the monomer represented by formula (A1) include, but are not limited to, those represented by the following formulas: A is the same as above.

[0037]

[0038] Specific examples of the cation of the monomer represented by formula (A2) include, but are not limited to, those represented by the following formulas: A is the same as above.

[0039] Specific examples of the anion of the monomer represented by formula (A3) include, but are not limited to, those represented by the following formulas: A is the same as above.

[0040]

[0041]

[0042] Specific examples of the anion of the monomer represented by formula (A4) include, but are not limited to, those represented by the following formulas: A is the same as above.

[0043] Specific examples of the anion of the monomer represented by formula (A5) include, but are not limited to, those represented by the following formulas: A is the same as above.

[0044] Specific examples of the anion of the monomer represented by formula (A6) include, but are not limited to, those represented by the following formulas: A is the same as above.

[0045]

[0046] In formulas (A1) and (A2), M - is a non-nucleophilic counter ion. The non-nucleophilic counter ion is preferably one represented by any one of the following formulae (M-1) to (M-6).

[0047] In formula (M-1), Q 11 and Q 12 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. fa1 is a hydrocarbyl group having 1 to 35 carbon atoms which may contain a heteroatom; and x is an integer of 0 to 4.

[0048] In formula (M-2), R fb1 and R fb2 are each independently a fluorine atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, and R fb1 and R fb2 are bonded to each other and form a bonded group (-CF2-SO2-N - It may form a ring together with —SO2—CF2—.

[0049] In formula (M-3), R fc1 , R fc2 and R fc3 are each independently a fluorine atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, and R fc1 and R fc2 are bonded to each other and form a bonded group (-CF2-SO2-C -It may form a ring together with —SO2—CF2—.

[0050] In formula (M-4), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom.

[0051] In formula (M-5), R fe1 represents an aliphatic hydrocarbylene group having 1 to 30 carbon atoms, a phenylene group which may be substituted with a fluorine atom or an iodine atom, or a naphthylene group which may be substituted with a fluorine atom or an iodine atom, and may contain at least one selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring, and some of the hydrogen atoms constituting the carbylene group may be substituted with a fluorine atom or a fluoroalkyl group.

[0052] In formula (M-6), R fe2 represents an aliphatic hydrocarbylene group having 1 to 30 carbon atoms, a phenylene group which may be substituted with a fluorine atom or an iodine atom, or a naphthylene group which may be substituted with a fluorine atom or an iodine atom, and may contain at least one selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring, and some of the hydrogen atoms constituting the carbylene group may be substituted with a fluorine atom or a fluoroalkyl group.

[0053] Specific examples of the non-nucleophilic counter ion include, but are not limited to, those represented by the following formulae:

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] In formulas (A3) to (A6), A +is an onium cation. Examples of the onium cation include a sulfonium cation, an iodonium cation, and an ammonium cation, and the sulfonium cation or the iodonium cation is preferred.

[0060] As the onium cation, a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2) is particularly preferred.

[0061] In formulas (cation-1) and (cation-2), R ct1 ~R ct5 R are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. ct1 ~R ct5 Specific examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. ct1 ~R ct5 The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those represented by R 1 ~R 3 In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, so that the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, or the like.

[0062] Also, R ct1 and R ct2However, they may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, specific examples of the ring structure include those represented by the following formulas. (wherein the dashed line represents R ct3 It is a bond with

[0063] Specific examples of the onium cation include, but are not limited to, the following:

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070] The monomer (B) is represented by the following formula (B1).

[0071] In formula (B1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 11 L is a saturated hydrocarbyl group having 1 to 6 carbon atoms which may contain at least one selected from a halogen atom, an ether bond, and a carbonyl group. B1 is a single bond, a carbonyloxy group, or an amide group. B2 is a single bond, or an alkanediyl group having 1 to 7 carbon atoms which may contain at least one bond selected from an ether bond and a carbonyl group. c1 is an integer satisfying the condition 0≦c1≦5+2(c3)−c2. c2 is 1, 2, 3, 4, or 5. c3 is 0, 1, or 2. When c1 is 2 or more, each R 11 may be the same as or different from each other.

[0072] In formula (B1), R 11Examples of the hydrocarbyl group having 1 to 6 carbon atoms and optionally containing at least one selected from an ether bond and a carbonyl group include, but are not limited to, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, and groups shown below. (In the formula, the dashed lines represent bonds.)

[0073] In formula (B1), L B2 Examples of the alkanediyl group having 1 to 7 carbon atoms and optionally containing at least one selected from an ether bond represented by the following formula and a carbonyl group include, but are not limited to, a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, and the following: (In the formula, the dashed lines represent bonds.)

[0074] Examples of the monomer represented by formula (B1) include, but are not limited to, the following: A is the same as above.

[0075]

[0076]

[0077] The monomer (C) preferably has an acid labile group, and is particularly preferably one represented by the following formula (C1), (C2) or (C3).

[0078] In formulas (C1), (C2) and (C3), R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. AL are each independently an acid labile group. 21 and R 22are each independently a halogen atom or a halogen atom of a saturated hydrocarbyl group having 1 to 6 carbon atoms which may contain at least one selected from an ether bond and a carbonyl group. C1 are each independently a single bond, a carbonyloxy group, or an amide group. C2 are each independently a single bond, or an alkanediyl group having 1 to 7 carbon atoms which may contain an ether bond or a carbonyl group. d1 is an integer which satisfies 0≦d1≦5+2(d3)−d2. d2 is 1, 2, 3, 4, or 5. d3 is 0, 1, or 2. e1 is an integer which satisfies 0≦e1≦5+2(e3)−e2. e2 is 1, 2, 3, 4, or 5. e3 is 0, 1, or 2. When d1 is 2 or more, each R 21 may be the same or different, and when e1 is 2 or more, each R 22 may be the same as or different from each other.

[0079] R 21 and R 22 Examples of saturated hydrocarbyl groups having 1 to 6 carbon atoms and optionally containing an ether bond and a carbonyl group, as represented by the formula (I), include, but are not limited to, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a cyclopentyl group, and a cyclohexyl group. (In the formula, the dashed lines represent bonds.)

[0080] L C2 Examples of the alkanediyl group having 1 to 7 carbon atoms and optionally containing an ether bond or a carbonyl group, represented by the formula (I), include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, and the following groups, but are not limited to these. (In the formula, the dashed lines represent bonds.)

[0081] A polymer containing a repeating unit derived from a monomer represented by formula (C1), (C2) or (C3) is decomposed by the action of an acid to produce a carboxy group or a phenolic hydroxy group, and becomes alkali-soluble. A Various groups can be used as the alkyl group, and specific examples include groups represented by the following formulas (L1) to (L9), tertiary hydrocarbyl groups having 4 to 20, preferably 4 to 15, carbon atoms, trihydrocarbylsilyl groups in which each hydrocarbyl group has 1 to 6 carbon atoms, carbonyl groups, and hydrocarbyl groups having 4 to 20 carbon atoms and containing an ether bond or an ester bond. (In the formula, the dashed lines represent bonds.)

[0082] In formula (L1), R L01 and R L02 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10. The alkyl saturated hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 18 carbon atoms, such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, 2-ethylhexyl group, and n-octyl group; and cyclic saturated hydrocarbyl groups having 3 to 18 carbon atoms, such as a cyclopentyl group, cyclohexyl group, norbornyl group, tricyclodecanyl group, tetracyclododecanyl group, and adamantyl group.

[0083] In formula (L1), R L03 is a hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, which may contain a heteroatom. Examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic, but a saturated hydrocarbyl group is preferred. In addition, some of the hydrogen atoms of the saturated hydrocarbyl group may be substituted with a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, an oxo group, an amino group, a saturated hydrocarbylamino group, or the like, and some of the -CH2- of the saturated hydrocarbyl group may be substituted with a heteroatom-containing group such as an oxygen atom. Examples of the saturated hydrocarbyl group include R L01 and RL02 Examples of the substituted saturated hydrocarbyl group include the same as those exemplified above. Furthermore, examples of the substituted saturated hydrocarbyl group include the groups shown below.

[0084] R L01 , R L02 and R L03 Any two of may be bonded to each other to form a ring together with the carbon atom to which they are bonded or together with the carbon atom and oxygen atom to which they are bonded. When a ring is formed, the group formed by bonding these is preferably an alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms.

[0085] In formula (L2), R L04 is a tertiary hydrocarbyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, a trihydrocarbylsilyl group in which each hydrocarbyl group is a hydrocarbyl group having 1 to 6 carbon atoms, a carbonyl group, a saturated hydrocarbyl group having 4 to 20 carbon atoms containing an ether bond or an ester bond, or a group represented by formula (L1). k is an integer of 0 to 6.

[0086] R L04The tertiary hydrocarbyl group represented by the formula (I) may be branched or cyclic, and specific examples thereof include tert-butyl, tert-pentyl, 1,1-diethylpropyl, 2-cyclopentylpropan-2-yl, 2-cyclohexylpropan-2-yl, 2-(bicyclo[2.2.1]heptan-2-yl)propan-2-yl, 2-(adamantan-1-yl)propan-2-yl, 1-ethylcyclopentyl, 1-butylcyclopentyl, 1-ethylcyclohexyl, 1-butylcyclohexyl, 1-ethyl-2-cyclopentenyl, 1-ethyl-2-cyclohexenyl, 2-methyl-2-adamantyl, and 2-ethyl-2-adamantyl. Examples of the trihydrocarbylsilyl group include trimethylsilyl, triethylsilyl, and dimethyl-tert-butylsilyl. Examples of the saturated hydrocarbyl group containing a carbonyl group, an ether bond, or an ester bond include a 3-oxocyclohexyl group, a 4-methyl-2-oxooxan-4-yl group, and a 5-methyl-2-oxooxolan-5-yl group.

[0087] In formula (L3), R L05is a saturated hydrocarbyl group having 1 to 8 carbon atoms which may contain a heteroatom, or an aryl group having 6 to 20 carbon atoms which may contain a heteroatom. The saturated hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, and n-hexyl; and cyclic saturated hydrocarbyl groups such as cyclopentyl and cyclohexyl. In addition, some of the hydrogen atoms of the saturated hydrocarbyl group may be substituted with a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, a carboxy group, a saturated hydrocarbyloxycarbonyl group having 1 to 8 carbon atoms, an oxo group, an amino group, a saturated hydrocarbylamino group having 1 to 8 carbon atoms, a cyano group, a mercapto group, a saturated hydrocarbylthio group having 1 to 8 carbon atoms, a sulfo group, or the like. Examples of the aryl group include a phenyl group, a methylphenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a pyrenyl group, etc. Some of the hydrogen atoms of the aryl group may be substituted with a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, a carboxy group, a saturated hydrocarbylcarbonyl group having 1 to 8 carbon atoms, an oxo group, an amino group, a saturated hydrocarbylamino group having 1 to 8 carbon atoms, a cyano group, a mercapto group, a saturated hydrocarbylthio group having 1 to 8 carbon atoms, a sulfo group, etc.

[0088] In formula (L3), m is 0 or 1, n is 0, 1, 2 or 3, and 2m+n=2 or 3.

[0089] In formula (L4), R L06 is a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, or an aryl group having 6 to 20 carbon atoms which may contain a heteroatom. Specific examples of the saturated hydrocarbyl group and the aryl group include R L05 Examples of the saturated hydrocarbyl group and aryl group represented by the following formula include the same as those exemplified above.

[0090] In formula (L4), R L07 ~R L16are each independently a hydrogen atom or a hydrocarbyl group having 1 to 15 carbon atoms. The hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic, but is preferably a saturated hydrocarbyl group. Specific examples of the hydrocarbyl group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, n-nonyl, and n-decyl; and cyclic saturated hydrocarbyl groups such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, and cyclohexylbutyl. In addition, some of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, a carboxy group, a saturated hydrocarbyloxycarbonyl group having 1 to 8 carbon atoms, an oxo group, an amino group, a saturated hydrocarbylamino group having 1 to 8 carbon atoms, a cyano group, a mercapto group, a saturated hydrocarbylthio group having 1 to 8 carbon atoms, a sulfo group, or the like. L07 ~R L16 Two selected from these may be bonded to each other to form a ring together with the carbon atoms to which they are bonded (for example, R L07 and R L08 , R L07 and R L09 , R L08 and R L10 , R L09 and R L10 , R L11 and R L12 , R L13 and R L14 In this case, the group participating in the ring formation is a hydrocarbylene group having 1 to 15 carbon atoms. Examples of the hydrocarbylene group include those obtained by removing one hydrogen atom from the hydrocarbyl groups exemplified above. L07 ~R L16 may bond to adjacent carbon atoms without any intervening bond to form a double bond (for example, R L07 and R L09 , R L09 and R L15, R L13 and R L15 etc.).

[0091] In formula (L5), R L17 ~R L19 are each independently a hydroxy group, a halogen atom, an alkyl group having 1 to 15 carbon atoms which may contain a heteroatom, or an aryl group having 6 to 15 carbon atoms which may contain a heteroatom. The saturated hydrocarbyl group may be linear, branched, or cyclic, and specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-ethylhexyl, and n-octyl; and cyclic saturated hydrocarbyl groups such as cyclopentyl, cyclohexyl, 1-adamantyl, and 2-adamantyl. Examples of the aryl group include a phenyl group and a naphthyl group. The aryl group may contain a hydroxy group, a halogen atom, or the like.

[0092] In formula (L6), R L20 is a cyclic saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, or an aryl group having 6 to 20 carbon atoms which may contain a heteroatom. Specific examples of the cyclic saturated hydrocarbyl group and the aryl group include R L05 Examples of the saturated hydrocarbyl group and aryl group represented by the following formula include the same as those exemplified above.

[0093] In formula (L7), R L21 is a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, or an aryl group having 6 to 20 carbon atoms which may contain a heteroatom. Specific examples of the saturated hydrocarbyl group and the aryl group include R L05 Examples of the saturated hydrocarbyl group and aryl group represented by R L22 and R L23 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R L07 ~R L16Examples of the hydrocarbyl group represented by R L22 and R L23 may be bonded to each other to form a substituted or unsubstituted cyclopentane ring or a substituted or unsubstituted cyclohexane ring together with the carbon atoms to which they are attached. L24 is a divalent group which, together with the carbon atom to which it is attached, forms a substituted or unsubstituted cyclopentane ring, a substituted or unsubstituted cyclohexane ring, or a substituted or unsubstituted norbornane ring.

[0094] In formula (L8), R L25 is a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, or an aryl group having 6 to 20 carbon atoms which may contain a heteroatom. Specific examples of the saturated hydrocarbyl group and the aryl group include R L05 Examples of the saturated hydrocarbyl group and aryl group represented by R L26 and R L27 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R L07 ~R L16 Examples of the hydrocarbyl group represented by R L26 and R L27 may be bonded to each other to form a substituted or unsubstituted cyclopentane ring or a substituted or unsubstituted cyclohexane ring together with the carbon atoms to which they are attached. L28 is a divalent group which, together with the carbon atom to which it is attached, forms a substituted or unsubstituted cyclopentane ring, a substituted or unsubstituted cyclohexane ring, or a substituted or unsubstituted norbornane ring.

[0095] In formula (L9), R L29 is a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, or an aryl group having 6 to 20 carbon atoms which may contain a heteroatom. Specific examples of the saturated hydrocarbyl group and the aryl group include RL05 Examples of the saturated hydrocarbyl group and aryl group represented by R L30 and R L31 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R L07 ~R L16 Examples of the hydrocarbyl group represented by R L30 and R L31 may be bonded to each other to form a substituted or unsubstituted cyclopentane ring or a substituted or unsubstituted cyclohexane ring together with the carbon atoms to which they are attached. L32 is a divalent group which, together with the carbon atom to which it is attached, forms a substituted or unsubstituted cyclopentane ring, a substituted or unsubstituted cyclohexane ring, or a substituted or unsubstituted norbornane ring.

[0096] Among the acid labile groups represented by formula (L1), linear or branched groups include, but are not limited to, those shown below.

[0097] Among the acid labile groups represented by formula (L1), examples of cyclic groups include tetrahydrofuran-2-yl, 2-methyltetrahydrofuran-2-yl, tetrahydropyran-2-yl, and 2-methyltetrahydropyran-2-yl.

[0098] Examples of the acid labile group represented by formula (L2) include a tert-butoxycarbonyl group, a tert-butoxycarbonylmethyl group, a tert-pentyloxycarbonyl group, a tert-pentyloxycarbonylmethyl group, a 1,1-diethylpropyloxycarbonyl group, a 1,1-diethylpropyloxycarbonylmethyl group, a 1-ethylcyclopentyloxycarbonyl group, a 1-ethylcyclopentyloxycarbonylmethyl group, a 1-ethyl-2-cyclopentenyloxycarbonyl group, a 1-ethyl-2-cyclopentenyloxycarbonylmethyl group, a 1-ethoxyethoxycarbonylmethyl group, a 2-tetrahydropyranyloxycarbonylmethyl group, and a 2-tetrahydrofuranyloxycarbonylmethyl group.

[0099] Examples of the acid labile group represented by formula (L3) include a 1-methylcyclopentyl group, a 1-ethylcyclopentyl group, a 1-n-propylcyclopentyl group, a 1-isopropylcyclopentyl group, a 1-n-butylcyclopentyl group, a 1-sec-butylcyclopentyl group, a 1-tert-butylcyclopentyl group, a 1-cyclohexylcyclopentyl group, a 1-(4-methoxy-n-butyl)cyclopentyl group, a 1-methylcyclohexyl group, a 1-ethylcyclohexyl group, a 3-methyl-1-cyclopenten-3-yl group, a 3-ethyl-1-cyclopenten-3-yl group, a 3-methyl-1-cyclohexen-3-yl group, and a 3-ethyl-1-cyclohexen-3-yl group.

[0100] As the acid labile group represented by formula (L4), groups represented by the following formulae (L4-1) to (L4-4) are particularly preferred.

[0101] In formulas (L4-1) to (L4-4), the dashed lines represent the bonding positions and bonding directions. L41are each independently a hydrocarbyl group having 1 to 10 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic, but is preferably a saturated hydrocarbyl group. Specific examples of the hydrocarbyl group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, and n-hexyl; and cyclic saturated hydrocarbyl groups such as cyclopentyl and cyclohexyl.

[0102] The groups represented by formulae (L4-1) to (L4-4) may have stereoisomers (enantiomers or diastereomers), and formulae (L4-1) to (L4-4) represent all of these stereoisomers. When the acid labile group is a group represented by formula (L4), it may contain multiple stereoisomers.

[0103] For example, formula (L4-3) represents one or a mixture of two selected from groups represented by the following formulae (L4-3-1) and (L4-3-2). (In the formula, R L41 The dashed lines represent the bond positions and bond directions.

[0104] Furthermore, formula (L4-4) represents one or a mixture of two or more selected from groups represented by the following formulae (L4-4-1) to (L4-4-4). (In the formula, R L41 The dashed lines represent the bond positions and bond directions.

[0105] Formulas (L4-1) to (L4-4), (L4-3-1), (L4-3-2) and formulas (L4-4-1) to (L4-4-4) also represent their enantiomers and mixtures of enantiomers.

[0106] High reactivity in an acid-catalyzed elimination reaction is achieved by bonding the groups represented by formulae (L4-1) to (L4-4), (L4-3-1), (L4-3-2), and (L4-4-1) to (L4-4-4) in the exo direction relative to the bicyclo[2.2.1]heptane ring (see JP 2000-336121 A). In the production of a monomer having a bicyclo[2.2.1]heptane skeleton and a tertiary exo-saturated hydrocarbyl group as a substituent, a monomer substituted with an endo-saturated hydrocarbyl group represented by the following formulae (L4-1-endo) to (L4-4-endo) may be included. To achieve good reactivity, the exo ratio is preferably 50 mol % or more, and more preferably 80 mol % or more. (In the formula, R L41 The dashed lines represent the bond positions and bond directions.

[0107] Examples of the acid labile group represented by formula (L4) include, but are not limited to, the groups shown below. (In the formula, the dashed lines represent bonds.)

[0108] Examples of the acid labile group represented by formula (L5) include, but are not limited to, a tert-butyl group, a tert-pentyl group, and the groups shown below. (In the formula, the dashed lines represent bonds.)

[0109] Examples of the acid labile group represented by formula (L6) include, but are not limited to, the groups shown below. (In the formula, the dashed lines represent bonds.)

[0110] Examples of the acid labile group represented by formula (L7) include, but are not limited to, the groups shown below. (In the formula, the dashed lines represent bonds.)

[0111] Examples of the acid labile group represented by formula (L8) include, but are not limited to, the groups shown below. (In the formula, the dashed lines represent bonds.)

[0112] Examples of the acid labile group represented by formula (L9) include, but are not limited to, the groups shown below. (In the formula, the dashed lines represent bonds.)

[0113] Specific examples of the monomer represented by formula (C1) include, but are not limited to, those shown below. A is the same as above.

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120] Specific examples of the monomer represented by formula (C2) include, but are not limited to, those shown below. A is the same as above.

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128] Specific examples of the monomer represented by formula (C3) include, but are not limited to, those shown below. A is the same as above.

[0129]

[0130] Also, R ALAmong the acid labile groups represented by the formula (I), the tertiary alkyl group having 4 to 20 carbon atoms, the trialkylsilyl group in which each alkyl group has 1 to 6 carbon atoms, and the oxoalkyl group having 4 to 20 carbon atoms are each represented by the formula (I), (II), (III), (IV), (IV), (IV), (VI), (VII ... L04 Examples of the above-mentioned methods are the same as those described above.

[0131] In addition to the monomers (A) to (C), the raw material may contain, as necessary, at least one repeating unit selected from a monomer represented by the following formula (D) (hereinafter also referred to as monomer (D)), a monomer represented by the following formula (E) (hereinafter also referred to as monomer (E)), and a monomer represented by the following formula (F) (hereinafter also referred to as monomer (F)):

[0132] In formulas (D) to (F), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 31 and R 32 are each independently a hydrogen atom or a hydroxy group. 33 is a substituent having a lactone structure or a substituent having a sultone structure. 34 is a hydrogen atom, a monovalent fluorinated hydrocarbon group having 1 to 15 carbon atoms, or a monovalent fluoroalcohol-containing substituent having 1 to 15 carbon atoms.

[0133] Specific examples of the monomer (D) include, but are not limited to, the following: A is the same as above.

[0134] Specific examples of the monomer (E) include, but are not limited to, the following: A is the same as above.

[0135]

[0136]

[0137]

[0138]

[0139] Specific examples of the monomer (F) include, but are not limited to, the following: A is the same as above.

[0140] The raw materials may further contain, as necessary, monomers having a carbon-carbon double bond other than those mentioned above, for example, substituted acrylic esters such as methyl methacrylate, methyl crotonate, dimethyl maleate, and dimethyl itaconate; unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid; norbornene, norbornene derivatives, tetracyclo[4.4.0.1] 2,5 .17 7,1 0 ]Other monomers such as cyclic olefins such as dodecene derivatives; unsaturated acid anhydrides such as itaconic anhydride; α-methylene-γ-butyrolactones; and α-methylstyrenes may also be included.

[0141] In step (1), the preferred proportions of each monomer used can be, for example, within the following ranges (mol %), but are not limited thereto: (I) Monomer (A) 1 to 50 mol %, preferably 1 to 30 mol %, more preferably 1 to 20 mol %, based on the total amount of monomers; (II) Monomer (B) 1 to 98 mol % or less, preferably 1 to 80 mol %, more preferably 10 to 70 mol %, based on the total amount of monomers; (III) Monomer (C) 1 to 98 mol %, preferably 1 to 80 mol %, more preferably 10 to 70 mol %, based on the total amount of monomers; (IV) One or more monomers other than monomers (A) to (C) 0 to 97 mol %, preferably 0 to 70 mol %, more preferably 0 to 50 mol %, based on the total amount of monomers.

[0142] <RAFT Agent> The RAFT agent introduces a structure represented by the following formula (X-1) or (X-2) into the terminal of a polymer.

[0143] In formulas (X-1) and (X-2), R X1 and R X2 are each independently a saturated hydrocarbyl group having 2 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, which may contain a heteroatom. The dashed line represents a bond to a carbon atom in the polymer main chain.

[0144] R X1 and R X2 The saturated hydrocarbyl group having 2 to 20 carbon atoms and represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, an n-tetradecyl group, an n-hexadecyl group, an n-octadecyl group, and an n-eicosanyl group; and cyclic saturated hydrocarbyl groups such as a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a cyclodecyl group, a cyclododecyl group, a 1-adamantyl group, a 2-adamantyl group, a 1-methylcyclopentyl group, a 1-isopropylcyclopentyl group, a 1-methylcyclohexyl group, a 1-isopropylcyclohexyl group, a 1-methyladamantyl group, and a 1-ethyladamantyl group.

[0145] R X1 and R X2 Specific examples of the aralkyl group having 7 to 20 carbon atoms represented by the formula (R) include a benzyl group, a phenethyl group, a 4-methoxybenzyl group, and a 9-anthracenylmethyl group. X1 and R X2 Specific examples of the aryl group having 6 to 20 carbon atoms represented by the formula (I) include a phenyl group, a naphthyl group, a 4-methoxyphenyl group, a 2-anthracenyl group, and a 9-anthracenyl group.

[0146] As the RAFT agent, a (meth)acrylate type monomer or an aromatic vinyl type monomer such as styrene is used, and therefore a compound represented by the following formula (CTA-1) or (CTA-2) is preferred.

[0147] In formulas (CTA-1) and (CTA-2), R X1 and R X2 are each independently a saturated hydrocarbyl group having 2 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, which may contain a heteroatom. 1 and Z 2each independently represents a saturated hydrocarbylthio group having 3 to 20 carbon atoms, an aralkylthio group having 7 to 20 carbon atoms, a heterocyclyl group having 5 to 20 carbon atoms, -N(Z A )(Z B ), -COOZ A , -OCOZ A , -CON(Z A )(Z B ), -P(=O)(OZ A )2 or -O-P(=O)(Z A )(Z B ) is. Z A and Z B are each independently a saturated hydrocarbyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms; Z 1 and Z 2 may have some or all of the hydrogen atoms bonded to the carbon atoms substituted with a cyano group, a carboxy group, or the like.

[0148] The RAFT agents (CTA-1) and (CTA-2) are a trithiocarbonate compound and a dithioester compound, respectively. Specific examples of the trithiocarbonate compound include 2-cyano-2-propyldodecyltrithiocarbonate, 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid, cyanomethyldodecyltrithiocarbonate, and 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid. Specific examples of the dithioester compound include 1-ethoxycarbonyl-1-phenylmethylbenzodithioate, 2-phenyl-2-propylbenzodithioate, 4-cyano-4-(phenylthiocarbonylthio)pentanoic acid, and 2-cyano-2-propylbenzodithioate.

[0149] Among the RAFT agents, it is preferable to use 2-cyano-2-propyldodecyltrithiocarbonate as a trithiocarbonate compound and 1-ethoxycarbonyl-1-phenylmethylbenzodithioate as a dithioester compound, from the viewpoint of easy availability.

[0150] The amount of the RAFT agent used in step (1) is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, per 100 parts by mass of the total monomers. The upper limit of the amount used is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, per 100 parts by mass of the total monomers. The RAFT agents may be used alone or in combination of two or more.

[0151] <Polymerization initiator> Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, etc. The amount of the polymerization initiator used is preferably 0.01 to 25 mol % based on the total amount of the monomers to be polymerized.

[0152] <Polymerization Solvent> In step (1), the living radical polymerization reaction is preferably carried out by solution polymerization for the purpose of supplying various monomers homogeneously to the reaction system. The solvent (S) used in the polymerization reaction is preferably one containing at least one selected from the group consisting of those represented by the following formula (S-1) and those represented by the following formula (S-2):

[0153] In formulas (S-1) and (S-2), R s1 is a hydrogen atom, a hydroxy group, or an optionally substituted saturated hydrocarbyl group having 1 to 8 carbon atoms. s2 ~R s4 are each independently a hydrogen atom, an optionally substituted saturated hydrocarbyl group having 1 to 8 carbon atoms, or an optionally substituted saturated hydrocarbyl carbonyl group having 2 to 9 carbon atoms. p is 1, 2, or 3. q is 0, 1, or 2. r is 1, 2, or 3.

[0154] R s1 ~R s4 and R s2 ~R s4The saturated hydrocarbyl moiety of the optionally substituted saturated hydrocarbyl carbonyl group having 2 to 9 carbon atoms, represented by the formula (I), may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, and octyl; cyclic saturated hydrocarbyl groups such as cyclopentyl and cyclohexyl; and groups in which some of the hydrogen atoms of these groups have been substituted with hydroxy groups or the like.

[0155] Examples of the solvent represented by formula (S-1) include, but are not limited to, the following.

[0156] Examples of the solvent represented by formula (S-2) include, but are not limited to, the following.

[0157] The amount of solvent (S) used is preferably 1 to 100% by mass, more preferably 10 to 100% by mass, and even more preferably 20 to 100% by mass, of the total solvent used in the polymerization. By using solvent (S), the monomer (A) can be dissolved at a high concentration, making it possible to increase the monomer concentration of the monomer solution compared to conventional methods. In particular, when a solvent represented by formula (S-1) is used, the monomer (A) can be dissolved at a high concentration. This facilitates an increase in the monomer conversion rate in the polymerization reaction, and reduces the amount of residual monomer after the polymerization reaction.

[0158] Other organic solvents that can be used during polymerization include, in addition to those exemplified as the solvent (S), toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, methyl ethyl ketone (MEK), etc., which may be used in combination with the solvent (S). If necessary, a step of removing dissolved oxygen in the solvent from the system by bubbling with a nitrogen stream or reducing the pressure may be carried out before the polymerization reaction.

[0159] In step (1), the monomer concentration in the monomer solution is preferably 30 to 60% by mass. By carrying out the living radical polymerization reaction in this manner, the monomer is sufficiently consumed within a reaction time that does not impair production efficiency, and it becomes possible to keep the amount of residual monomer after polymerization and purification low.

[0160] The living radical polymerization reaction can be carried out by an appropriate method selected from the following: (1) a method in which all of the monomers, polymerization initiator, and RAFT agent are added to and dissolved in solvent (S) at once in a reactor, and the reactor is then heated to initiate the reaction; (2) a method in which a solution of the monomers, polymerization initiator, and RAFT agent in solvent (S) is supplied to a reactor that has been charged with a portion of solvent (S) and heated in advance, and the reaction is initiated; or (3) a method in which a solution of the monomers and polymerization initiator in solvent (S) is supplied to a reactor that has been charged with a RAFT agent and a portion of solvent (S) and heated in advance, and the reaction is initiated. In the cases of methods (2) and (3), the solutions of the monomers, initiator, and RAFT agent may be prepared by preparing independent solutions and supplying them to the reactor. During the waiting time, radicals generated from the initiator may cause the polymerization reaction to proceed, resulting in the production of ultra-high molecular weight polymers. From the viewpoint of quality control, it is preferable to prepare at least the monomer solution and the initiator solution independently and then add them dropwise.

[0161] In the living radical polymerization reaction, the reaction temperature is preferably 50 to 150°C, more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, more preferably 2 to 12 hours from the viewpoint of production efficiency. Furthermore, the amounts of the monomers (A) to (C) remaining in the reaction solution containing polymer P-1 after the living radical polymerization reaction are preferably less than 2.0% by mass, less than 1.0% by mass, and less than 2.0% by mass, respectively. Generally, in living radical polymerization with a repeating unit (B) having a phenolic hydroxy group, such as hydroxystyrene, the active species are deactivated, making it difficult to increase the living nature of the polymerization reaction and the consumption rate of each monomer. However, the polymerization conditions of the present invention maintain high living nature and enable the consumption rate of each monomer to be increased in a short period of time. The amount of remaining monomer can be quantified primarily by high-performance liquid chromatography.

[0162] After the living radical polymerization reaction step, a purification step may be included, as necessary, in which the reaction solution is added to a poor solvent and reprecipitation or the like is carried out. The poor solvent used here can be appropriately selected depending on the type of polymer, and representative examples include, but are not limited to, hydrocarbons such as toluene, xylene, hexane, and heptane; ethers such as diethyl ether, tetrahydrofuran, and dibutyl ether; ketones such as acetone and 2-butanone; esters such as ether acetate and butyl acetate; and water. These solvents may be used alone or in combination of two or more.

[0163] [Step (2)] The subsequent step (2) is a step in which a radical generator and a thiol compound are added to a solution containing the polymer P-1 obtained in step (1), and the mixture is heated to remove the terminal structure from the main chain of the polymer P-1, thereby obtaining a polymer P. This operation replaces the terminal structure possessed by the polymer P-1 with a hydrogen atom. Note that, although undecomposed radical generator may remain among the radical generators used in step (1), in order to replace the terminal structure with a hydrogen atom highly efficiently in a short period of time, it is preferable to add an additional radical generator at the same time as adding the thiol compound.

[0164] The radical generator used in step (2) can be appropriately selected from the same radical generators as those exemplified in step (1). The amount of the radical initiator used is preferably 0.5 to 10 mol, more preferably 0.5 to 2 mol, per mol of the RAFT agent used in step (1).

[0165] In the present invention, the thiol compound used in step (2) is preferably a compound represented by the following formula (SH-1) or (SH-2).

[0166] In formula (SH-1), R SH1is a hydrocarbylene group having 1 to 3 carbon atoms. Specific examples of the hydrocarbylene group include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, and a propane-2,2-diyl group.

[0167] In formula (SH-1), R SH2 is an aliphatic hydrocarbyl group having 4 to 8 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, or an aryl group having 6 to 18 carbon atoms, which may contain a heteroatom. Examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.

[0168] R SH2 The aliphatic hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include linear or branched aliphatic hydrocarbyl groups such as n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-pentyl, isopentyl, sec-pentyl, 3-pentyl, tert-pentyl, neopentyl, n-hexyl, 3-methylpentan-3-yl, 2,3-dimethylbutan-2-yl, n-heptyl, 2,3,4-trimethylpentan-3-yl, n-octyl, tetradecyl, hexadecyl, and octadecyl groups. cycloaliphatic hydrocarbyl groups such as a cyclopentyl group, a 1-methylcyclopentyl group, a 1-ethylcyclopentyl group, a 1-vinylcyclopentyl group, a cyclohexyl group, a 1-methylcyclohexyl group, a 1-ethylcyclohexyl group, a 1-vinylcyclohexyl group, a norbornyl group, a 1-methylnorbornyl group, a cyclooctyl group, a cyclodecyl group, a cyclododecyl group, a 1-adamantyl group, a 2-adamantyl group, a 1-methyladamantyl group, and a 1-ethyladamantyl group.

[0169] R SH2 Specific examples of the aralkyl group having 7 to 18 carbon atoms represented by the formula (R) include a benzyl group, a phenethyl group, a 4-methoxybenzyl group, and a 9-anthracenylmethyl group. SH2Specific examples of the aryl group having 6 to 18 carbon atoms represented by the formula (I) include a phenyl group, a naphthyl group, a 4-methoxyphenyl group, a 2-anthracenyl group, and a 9-anthracenyl group.

[0170] In formula (SH-2), R SH3 is a saturated hydrocarbyl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, or an aryl group having 6 to 18 carbon atoms, which may contain a heteroatom.

[0171] R SH3 The saturated hydrocarbyl group represented by the formula (I) may be linear, branched or cyclic, and specific examples thereof include an n-hexyl group, a 3-methylpentyl group, an n-heptyl group, an n-octyl group, a 1-ethylhexyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, a 2,2,4,6,6-pentamethylheptan-4-yl group, an n-tetradecyl group, an n-hexadecyl group, an n-octadecyl group, an n-eicosanyl group, and a 2,3,3,4,4,5-pentamethylhexan-2-yl group.

[0172] R SH3 Specific examples of the aralkyl group having 7 to 18 carbon atoms represented by the formula (R) include a benzyl group, a phenethyl group, a 4-methoxybenzyl group, and a 9-anthracenylmethyl group. SH2 Specific examples of the aryl group having 6 to 18 carbon atoms represented by the formula (I) include a phenyl group, a naphthyl group, a 4-methoxyphenyl group, a 2-anthracenyl group, and a 9-anthracenyl group.

[0173] When a radical initiator is simultaneously present, the thiol compound acts on the terminals of the polymer P-1 obtained in step (1) and quickly replaces the terminals with hydrogen atoms. This mechanism is described in detail in JP 2006-2096 A. During this process, the RAFT agent is regenerated in the reaction system, and an active species derived from the initiator (active species I) and a thio radical (active species S) are generated after releasing a hydrogen radical. Below, an example is shown in which the terminals of the polymer P-1 are derived from trithiocarbonate, the radical initiator is dimethyl 2,2'-azobisisobutyrate, and the thiol is a compound represented by formula (SH-2).

[0174] After step (1), the solution containing polymer P-1 contains unreacted residual monomers, including monomers (A) to (C), although at low concentrations. The present inventors have confirmed, by analyzing and comparing the polymer solutions from steps (1) and (2), that as a side reaction during step (2), the active species I, active species S, and the regenerated RAFT agent act to continue the radical polymerization reaction between the residual monomers, thereby further reducing the amount of residual monomer.

[0175] When living radical polymerization is allowed to proceed sufficiently according to the method of step (1), the concentration of remaining monomers is extremely low relative to the concentrations of active species I derived from the initiator added in step (2), active species S generated from thiols after substituting the ends of polymer P-1 with hydrogen atoms, and the regenerated RAFT agent. Therefore, it is thought that the polymerization reaction between remaining monomers that proceeds in step (2) does not produce high-molecular-weight polymers, but mainly produces oligomers.

[0176] The polymer P-1X produced by the side reaction in step (2) has a low molecular weight and is therefore easily removed when the subsequent step (3) is carried out. However, due to the mechanism thereof, an active species S derived from a thiol is incorporated into the terminal of the polymer during polymerization of the remaining monomers. Therefore, the substituent of the thiol compound (SH-1) or (SH-2) is preferably a group that is highly soluble in an organic solvent and allows easy removal of the polymer in the polymer purification step.

[0177] As the compound represented by formula (SH-1), the following are preferred.

[0178]

[0179] As the compound represented by formula (SH-2), the following are preferred.

[0180] The amount of the thiol compound used in step (2) is preferably 1 to 20 mol, more preferably 1 to 4 mol, per mol of the RAFT agent used in step (1). The radical initiator and thiol compound added in step (2) may be added independently to a solution containing polymer P-1, or they may be mixed and added simultaneously to a solution containing polymer P-1. From the viewpoint of operational efficiency, it is preferable to simultaneously mix and dissolve the initiator and thiol compound in the aforementioned solvent (S) and add the resulting mixture to the P-1 solution. It is more preferable to subsequently add a mixed solution of the initiator and thiol to the reaction solution in which the living radical polymerization in step (1) has been carried out in solvent (S).

[0181] The reaction temperature in step (2) is preferably 50 to 150°C, more preferably 60 to 100°C. The reaction time in step (2) is preferably 2 to 24 hours, more preferably 2 to 5 hours from the viewpoint of production efficiency. The solution containing polymer P obtained in step (2) preferably has residual amounts of monomer (A), monomer (B), and monomer (C) remaining in the solution of less than 0.05% by mass, less than 0.01% by mass, and less than 0.05% by mass, respectively.

[0182] In step (2), the conversion efficiency of the terminal structure derived from the RAFT agent to a hydrogen atom (hereinafter also referred to as "terminal conversion efficiency") is preferably 95% or more, more preferably 98% or more, and even more preferably 100%. The terminal conversion efficiency (%) is 1 The terminal conversion efficiency is a value calculated using H-NMR measurement data and is represented by the following formula (Z): Terminal conversion efficiency=100−[{(A1 / R1) / (A2 / R2)}×100] (Z) (In formula (Z), A1 is the integral value of the peak derived from the terminal groups after contact of polymer T with the thiol group-containing compound, A2 is the integral value of the peak derived from the terminal groups before contact of polymer P-1 with the thiol group-containing compound, R1 is the peak integral value of the entire polymer excluding the terminal groups after contact of polymer P-1 with the thiol group-containing compound, and R2 is the peak integral value of the entire polymer excluding the terminal groups before contact of polymer P-1 with the thiol group-containing compound.)

[0183] [Step (3)] The subsequent step (3) is a step of purifying the polymer P by mixing the solution containing the polymer P obtained in step (2) with a poor solvent to precipitate the polymer P as a solid.

[0184] The method for obtaining the polymer as a solid can be appropriately selected from any of the following: (A) a method in which a solution containing polymer P is directly added from the reaction solution after step (2) to a poor solvent to obtain a solid (powder); (B) a method in which the solvent (S) used in steps (1) and (2) is removed by distillation under reduced pressure, while the polymer is dissolved in another solvent and the resulting solution is added to a poor solvent to obtain a solid (powder); (C) a method in which another solvent is added to the polymer solution, and then water is added to separate the polymer solution into an upper layer and a mixed solution of solvent (S) and water into a lower layer, and after removing the lower layer, the polymer solution whose concentration has been adjusted is added to a poor solvent to obtain a solid (powder); and (D) a method in which a solution containing polymer P is added to water to obtain a powder precipitated as a solid, and the powder is then collected by filtration, dissolved in another solvent, and added to a poor solvent to obtain a solid (powder).

[0185] Among these, methods (A) and (C) are particularly preferred in terms of process time and accuracy.

[0186] The poor solvent can be appropriately selected depending on the type of polymer, and typical examples include, but are not limited to, hydrocarbons such as toluene, xylene, hexane, and heptane; ethers such as diethyl ether, tetrahydrofuran, diisopropyl ether, and dibutyl ether; ketones such as acetone and 2-butanone; esters such as ethyl acetate and butyl acetate; water, etc. These solvents may be used alone or in combination of two or more.

[0187] The purification method of adding a polymer solution to a poor solvent to obtain a powder is carried out for the purpose of removing the low-molecular-weight polymer produced through steps (1) and (2) and the unreacted monomer. If necessary, the obtained powder can be prepared again in a solution, and the same purification can be repeated.

[0188] The polymer obtained by the method of the present invention preferably contains 0.05% by mass or less of the residual monomer (A), 0.01% by mass or less of the residual monomer (B), and 0.05% by mass or less of the residual monomer (C) that is decomposed by the action of an acid.

[0189] The weight average molecular weight (Mw) of the polymer obtained by the method of the present invention is preferably 1,000 to 30,000, and more preferably 3,000 to 20,000. In the present invention, Mw is a value measured by gel permeation chromatography (GPC) in terms of polystyrene. The polydispersity (Mw / Mn) of the polymer obtained by the method of the present invention is preferably 1.0 to 1.5, and more preferably 1.0 to 1.35.

[0190] [Method for Producing Polymer Solution] The polymer P obtained by the above method is preferably dissolved in a solvent to prepare a polymer solution (hereinafter also referred to as polymer solution PS) which is handled as a final product. The solvent contains at least propylene glycol monomethyl ether acetate (PGMEA). The solvent may further contain other solvents in addition to PGMEA. Specific examples thereof include ketones such as cyclohexanone and methyl-2-n-amyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol, as described in paragraphs

[0144] and

[0145] of JP 2008-111103 A; propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether; and diethylene glycol monomethyl ether (DMBE). Examples of the other solvent include ethers such as ethylene glycol dimethyl ether; esters such as propylene glycol monoethyl ether acetate, lactic acid ether, pyruvate ether, butyl acetate, methyl 3-methoxypropionate, 3-ethoxypropionic acid ether, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; lactones such as γ-butyrolactone (GBL); alcohols such as diacetone alcohol; and high-boiling alcohol solvents such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol. The other solvents may be used alone or in combination of two or more. When the solvent contains other solvents, the content of PGMEA is preferably 25 to 80% by mass, and more preferably 30 to 70% by mass, of the total solvent.

[0191] The polymer P is dissolved in a solvent and then filtered to obtain a polymer solution PS. Filtering can remove foreign matter and gels that may cause defects, and is effective in stabilizing quality.

[0192] The filter material used for the filter filtration may be a fluorocarbon, cellulose, nylon, polyester, or hydrocarbon material, but in the resist composition filtration process, a filter made of a fluorocarbon material known as Teflon (registered trademark), a hydrocarbon material such as polyethylene or polypropylene, or nylon is preferred. The pore size of the filter can be selected appropriately according to the target cleanliness, but is preferably 100 nm or less, more preferably 20 nm or less. Furthermore, these filters may be used alone or in combination.

[0193] The filtration method may be to pass the solution through a filter only once, but it is more preferable to circulate the solution and perform filtration multiple times. The filtration step can be performed in any order and any number of times in the polymer production process, but it is preferable to filter the reaction solution after the polymerization reaction, the polymer solution PS, or both.

[0194] The concentration of the polymer P in the polymer solution PS is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0195] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. Note that Mw is a polystyrene-equivalent value measured by gel permeation chromatography (GPC) using N,N-dimethylformamide as a solvent.

[0196] The reagents used in the examples are as follows: CTA-1: 2-cyano-2-propyl benzodithioate CTA-2: 2-cyano-2-propyl dodecyl trithiocarbonate I-1: 2,2'-azobisisobutyric acid dimethyl I-2: 2,2'-azobisisobutyronitrile SH-1: 1-dodecanethiol SH-2: tert-butyl thioglycolate SH-3: tert-dodecyl mercaptan

[0197] The monomers MA-1 to MA-12, MB-1 to MB-7 and MC-1 to MC-7 used in the examples are as follows:

[0198]

[0199]

[0200]

[0201] [1] Preparation of Polymers [Example 1-1] Preparation of Polymer P-1 Under a nitrogen atmosphere, 11.5 g of MA-1, 20.2 g of MB-2 (50% by mass PGMEA solution), 12.3 g of MC-1, and 6.1 g of MC-2 were dissolved in 21 g of GBL, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution A. Separately, 0.97 g of dimethyl 2,2'-azobisisobutyrate (I-1) was dissolved in 9.0 g of GBL to prepare Solution B, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution B. Furthermore, 2.79 g of CTA-1 was dissolved in 20.0 g of GBL, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution C, and then the reactor for Solution C was heated to a temperature of 80°C inside the reactor. Solution A and Solution B were added dropwise to the reaction solution of step RM-1 over a period of 2 hours, each independently, using a syringe pump. After completion of the dropwise addition, the polymerization solution was stirred for 6 hours while maintaining the temperature at 80°C, and then cooled to room temperature (the process up to this point is referred to as step RM-1). The solids concentration of the reaction solution of step RM-1 up to this point was 40% by mass. Next, 2.90 g of I-1 and 5.10 g of SH-1 were dissolved in 33.3 g of GBL, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare solution D. Solution D was added dropwise to the reaction solution of step RM-1 over a period of 5 minutes using a syringe pump. After completion of the dropwise addition, the temperature inside the reactor was again heated to 80°C, and the mixture was stirred for 2 hours while maintaining the temperature at 80°C, and then cooled to room temperature (the process up to this point is referred to as step RM-2). The solution from step RM-2 was then diluted with 250 g of methyl isobutyl ketone, mixed with 400 g of ultrapure water, and transferred to a separatory funnel. The lower layer separated into two layers was discarded, and the upper layer was recovered and concentrated at 40°C to prepare 160 g of a solution. The resulting solution was added dropwise to 1,000 g of diisopropyl ether, and the precipitated solid was filtered off and vacuum dried at 50°C for 20 hours to obtain polymer P-1 as a white solid (yield: 35 g, 88%). The Mw of polymer P-1 was 9,500, and the Mw / Mn was 1.32. The amount of residual MA-1 in step RM-1 was 0.85% by mass, the amount of residual MB-2 was 0.46% by mass, the amount of residual MC-1 was 1.05% by mass, and the amount of residual MC-2 was 0.90% by mass.In step RM-2, the amount of residual MA-1 was 0.03% by mass, the amount of residual MB-2 was less than the lower limit of quantitation (less than 0.01% by mass), the amount of residual MC-1 was 0.04% by mass, the amount of residual MC-2 was 0.02% by mass, and the terminal conversion efficiency was 100%. After reprecipitation, the amount of residual MA-1 in polymer P-1 was 0.01% by mass, the amount of residual MB-2 was less than the lower limit of quantitation (less than 0.01% by mass), the amount of residual MC-1 was less than the lower limit of quantitation (less than 0.01% by mass), and the amount of residual MC-2 was less than the lower limit of quantitation (less than 0.01% by mass).

[0202] Example 1-2: Preparation of Polymer P-2 Under a nitrogen atmosphere, 17.2 g of MA-2, 9.7 g of MB-1, 13.1 g of MC-1, and 3.23 g of CTA-2 were dissolved in 30.0 g of GBL in a reactor to prepare Solution A, and the reactor was heated to a temperature of 70°C. Separately, 0.51 g of I-2 was dissolved in 10.0 g of GBL, and solution B was prepared by degassing under reduced pressure for 20 minutes and replacing with nitrogen three times. Solution B was added dropwise to Solution A over 2 hours using a syringe pump. After the addition, the polymerization solution was stirred for 6 hours while maintaining the temperature at 70°C and then cooled to room temperature (the process up to this point is referred to as Step RM-1). The reaction solid concentration in Step RM-1 up to this point was 50% by mass. Next, 1.53 g of I-2 and 2.79 g of SH-2 were dissolved in 20.0 g of GBL, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare solution C. Solution C was added dropwise to the reaction solution from step RM-1 over 5 minutes using a syringe pump. After the dropwise addition was completed, the temperature inside the reactor was again heated to 70°C, stirred for 2 hours while maintaining the temperature at 70°C, and then cooled to room temperature (the process up to this point is referred to as step RM-2). Thereafter, the RM-2 solution was diluted with 250 g of methyl isobutyl ketone, mixed with 400 g of ultrapure water, and transferred to a separatory funnel. The lower layer, which separated into two layers, was discarded, and the upper layer was recovered and concentrated at 40°C to prepare 200 g of solution. The resulting solution was added dropwise to 1,000 g of diisopropyl ether, and the precipitated solid was filtered off and dried in vacuo at 50°C for 20 hours to obtain polymer P-2 as a white solid (yield: 37 g, 93%). The Mw of polymer P-2 was 10,000, and Mw / Mn was 1.31. The amount of residual MA-2 in step RM-1 was 0.95% by mass, the amount of residual MB-1 was 0.40% by mass, and the amount of residual MC-1 was 1.00% by mass. The amount of residual MA-2 in step RM-2 was 0.04% by mass, the amount of residual MB-1 was less than the lower limit of quantitation (less than 0.01% by mass), and the amount of residual MC-1 was 0.03% by mass, and the terminal conversion efficiency was 100%. After reprecipitation, the amount of residual MA-2 in polymer P-2 was 0.01% by mass, the amount of residual MB-1 was less than the lower limit of quantitation (less than 0.01% by mass), and the amount of residual MC-1 was less than the lower limit of quantitation (less than 0.01% by mass).

[0203] Example 1-3: Preparation of Polymer P-3 Under a nitrogen atmosphere, 17.7 g of MA-5, 6.9 g of MB-3, 15.4 g of MC-4, and 3.14 g of CTA-1 were dissolved in 48.9 g of GBL in a reactor. Degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution A. 0.50 g of I-2 was added to Solution A, and after confirming dissolution at room temperature, the reactor was heated to a temperature of 70°C. The polymerization solution was stirred for 8 hours while maintaining the temperature at 70°C and then cooled to room temperature (this process is referred to as Step RM-1). The solids concentration in the reaction solution of Step RM-1 up to this point was 45% by mass. Next, 1.49 g of I-1 and 2.71 g of SH-2 were dissolved in 25.4 g of PGME, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution B. Solution B. Using a syringe pump, the solution was added dropwise to the reaction solution from step RM-1 over 5 minutes. After completion of the addition, the temperature inside the reactor was again heated to 70°C, stirred for 2 hours while maintaining the temperature at 70°C, and cooled to room temperature (the process up to this point is referred to as step RM-2). Thereafter, the solution from step RM-2 was diluted with 36.8 g of PGME and added dropwise to 1,000 g of diisopropyl ether. The precipitated solid was filtered and dried in vacuo at 50°C for 20 hours to obtain polymer P-3 as a white solid (yield: 33 g, 83%). The Mw of polymer P-3 was 10,500, and the Mw / Mn was 1.28. The amount of residual MA-5 in step RM-1 was 0.98% by mass, the amount of residual MB-3 was 0.30% by mass, and the amount of residual MC-4 was 1.05% by mass. The amount of residual MA-5 in step RM-2 was 0.02% by mass, the amount of residual MB-3 was less than the lower limit of quantitation (less than 0.01% by mass), the amount of residual MC-4 was 0.01% by mass, and the terminal conversion efficiency was 100%. After reprecipitation, the amount of residual MA-5 in polymer P-1 was less than the lower limit of quantitation (less than 0.01% by mass), the amount of residual MB-3 was less than the lower limit of quantitation (less than 0.01% by mass), and the amount of residual MC-4 was less than the lower limit of quantitation (less than 0.01% by mass).

[0204] Comparative Example 1-1: Investigation of Production Conditions for Polymer P-3 -1 An attempt was made to prepare a monomer solution having the same composition as in Example 1-3 at the concentrations described in Example 4 of Patent Document 7. Specifically, 14.6 g of MA-5, 5.7 g of MB-3, and 12.7 g of MC-4 were mixed with 9.8 g of propylene glycol monomethyl ether, but the monomer MA-5 could not be dissolved.

[0205] Comparative Example 1-2: Investigation of Production Conditions for Polymer P-3 - 2 An attempt was made to prepare a monomer solution having the same composition as in Example 1-3 at the concentrations described in Example 4 of Patent Document 7. Specifically, 14.6 g of MA-5, 5.7 g of MB-3, and 12.7 g of MC-4 were mixed with 9.8 g of GBL, but the monomer MA-5 could not be dissolved.

[0206] Comparative Example 1-3: Preparation of Polymer CP-1 Under a nitrogen atmosphere, 17.7 g of MA-5, 6.9 g of MB-3, 15.4 g of MC-4, and 3.14 g of CTA-2 were dissolved in 42.8 g of GBL, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution A. Subsequently, 0.50 g of I-2 was dissolved in 6.1 g of GBL, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution B. The procedure thereafter was carried out with reference to the method described in Example 4 of Patent Document 7. That is, 3.5 g of Solution B was added to the reactor containing Solution A at room temperature, and then the flask temperature was raised to 80°C to initiate polymerization. The temperature inside the reactor was maintained at 80°C for three hours, and the remaining 3.1 g of Solution B was added, and the reaction was continued at 80°C for an additional three hours, after which the polymerization solution was cooled (the process up to this point is referred to as Step RM-1). Up to this point, the solids concentration in the reaction solution of step RM-1 was 45% by mass. Subsequently, 3.03 g of SH-3 was added, and the reaction was carried out at 80°C for 3 hours, after which the reaction solution was cooled (the process up to this point is referred to as step RM-2). Thereafter, the solution of step RM-2 was diluted with 36.8 g of PGME and added dropwise to 1,000 g of diisopropyl ether. The precipitated solid was separated by filtration and dried in vacuo at 50°C for 20 hours to obtain polymer CP-1 as an orange-yellow solid (yield: 28 g, 70%). The Mw of polymer CP-1 was 9,500, and the Mw / Mn was 1.52. The amount of residual MA-5 in step RM-1 was 1.90% by mass, the amount of residual MB-3 was 0.78% by mass, and the amount of residual MC-4 was 1.28% by mass. In step RM-2, the amount of residual MA-5 was 1.52% by mass, the amount of residual MB-3 was 0.26% by mass, and the amount of residual MC-4 was 0.78% by mass, resulting in a terminal conversion efficiency of 72%. After reprecipitation, the amount of residual MA-5 in polymer P-3 was 1.30% by mass, the amount of residual MB-3 was 0.10% by mass, and the amount of residual MC-4 was 0.48% by mass, resulting in a terminal conversion efficiency of 88% for solid polymer CP-1.

[0207] Comparative Example 1-4: Preparation of Polymer CP-2 Under a nitrogen atmosphere, 11.5 g of MA-1, 20.2 g of MB-2 (50% PGMEA solution), 12.3 g of MC-1, 6.1 g of MC-2, and 2.79 g of CTA-1 were dissolved in 30.0 g of GBL in a reactor, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution A. Separately, 0.97 g of I-1 was dissolved in 19.9 g of GBL, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution B. The temperature inside the reactor containing Solution A was heated to 80°C, and the subsequent steps were carried out with reference to the method described in Example 1 of Patent Document 8. Specifically, Solution B was supplied to the reactor containing Solution A, which was maintained at 80°C, over 5 minutes using a syringe pump, and the mixture was stirred for 5 hours while maintaining the temperature (the process up to this point is referred to as Step RM-1). Next, solution C, in which 28.97 g of I-1 was dissolved in 50 g of GBL, was added, and the mixture was stirred for 2 hours while maintaining the temperature at 80°C, and then cooled to room temperature (the process up to this point is referred to as step RM-2). The solution from step RM-2 was then diluted with 250 g of methyl isobutyl ketone, mixed with 400 g of ultrapure water, and transferred to a separatory funnel. The lower layer separated into two layers, and discarded, while the upper layer was recovered and concentrated at 40°C to prepare 160 g of solution. The resulting solution was added dropwise to 1,000 g of diisopropyl ether, and the precipitated solid was filtered and dried in vacuo at 50°C for 20 hours to obtain polymer CP-2 as a white solid (yield: 38 g, 95%). The Mw of polymer CP-2 was 9,300, and the Mw / Mn was 1.45. In step RM-1, the amount of residual MA-1 was 1.20% by mass, the amount of residual MB-2 was 0.78% by mass, the amount of residual MC-1 was 1.25% by mass, and the amount of residual MC-2 was 1.00% by mass. In step RM-2, the amount of residual MA-1 was 0.03% by mass, the amount of residual MB-2 was less than the lower limit of quantitation (less than 0.01% by mass), the amount of residual MC-1 was 0.04% by mass, and the amount of residual MC-2 was 0.02% by mass, resulting in a terminal conversion efficiency of 90%. After reprecipitation, the amount of residual MA-1 in polymer CP-2 was 0.01% by mass, the amount of residual MB-2 was less than the lower limit of quantitation (less than 0.01% by mass), the amount of residual MC-1 was less than the lower limit of quantitation (less than 0.01% by mass), and the amount of residual MC-2 was less than the lower limit of quantitation (less than 0.01% by mass), resulting in a terminal conversion efficiency of 94% for solid polymer CP-2.

[0208] Comparative Example 1-5: Preparation of Polymer CP-3 Under a nitrogen atmosphere, 17.7 g of MA-5, 6.9 g of MB-3, and 15.4 g of MC-4 were dissolved in 39.5 g of GBL, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution A. Separately, 4.96 g of 2,2'-azobisisobutyronitrile was dissolved in 20.0 g of GBL, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times to prepare Solution B. 24.8 g of GBL was charged into a reactor, and degassing under reduced pressure for 20 minutes and nitrogen substitution were repeated three times, after which the temperature inside the reactor was heated to 80°C. Solutions A and B were added dropwise to the reactor using syringe pumps, independently, over a period of 4 hours. The polymerization solution was stirred for 4 hours while maintaining the temperature at 80°C, and then cooled to room temperature (the process up to this point is referred to as Step RM-1). Thereafter, the solution from step RM-1 was diluted with 250 g of methyl isobutyl ketone, mixed with 400 g of ultrapure water, and transferred to a separatory funnel. The lower layer separated into two layers was discarded, and the upper layer was recovered and concentrated at 40°C to prepare 160 g of a solution. The resulting solution was added dropwise to 1,000 g of diisopropyl ether, and the precipitated solid was separated by filtration and dried in vacuo at 50°C for 20 hours to obtain polymer CP-3 in the form of a white solid (yield: 36 g, 90%). The Mw of polymer CP-3 was 10,000, and the Mw / Mn was 1.64. The amount of residual MA-5 in step RM-1 was 1.20% by mass, the amount of residual MB-3 was 0.37% by mass, and the amount of residual MC-4 was 0.78% by mass. After reprecipitation, the amount of residual MA-5 in polymer P-3 was 0.96% by mass, the amount of residual MB-3 was 0.18% by mass, and the amount of residual MC-4 was 0.24% by mass.

[0209] [Examples 1-4 to 1-10] Polymers P-4 to P-10 were produced according to the methods of the above examples, while changing the monomers and composition ratios. Table 1 shows the raw materials and post-treatment conditions for the polymers produced in the examples and comparative examples, and Table 2 shows the analytical values ​​during the process, the terminal conversion efficiency, Mw, and Mw / Mn.

[0210]

[0211]

[0212] [2] Preparation of Polymer Solution [Example 2-1] The production process was carried out according to the method of Example 1-3, and the mixture was added dropwise to diisopropyl ether. The precipitated solid was filtered off to obtain polymer P-3 as a wet powder. The obtained wet powder was placed in a flask, and PGME was added to dissolve the wet powder. The mixture was then concentrated under reduced pressure at 40°C to remove diisopropyl ether. After concentration, the PGME content was determined by gas chromatography, and an appropriate amount of PGMEA was added to obtain a PGME / PGMEA solution of polymer P-3 (polymer concentration 10% by mass, PGME:PGMEA = 70:30 (mass ratio)). The solution was passed through a pipe connected in this order to a nylon filter (pore size 5 nm) and a polyethylene filter (pore size 1 nm), and filtered to obtain a solution.

[0213] Comparative Example 2-1 The production process was carried out according to the method of Comparative Example 1-4, and polymer CP-2 was obtained as a wet powder by adding dropwise to diisopropyl ether and filtering off the precipitated solid. The obtained wet powder was placed in a flask, and PGME was added to dissolve the wet powder. The solution was then concentrated under reduced pressure at 40°C to remove the diisopropyl ether. After concentration, the PGME content was determined by gas chromatography, and an appropriate amount of PGMEA was added to obtain a PGME / PGMEEA solution of polymer CP-2 (polymer concentration 10% by mass, PGME:PGMEA = 70:30 (mass ratio)). This solution was passed through a pipe connected in this order to a nylon filter (pore size 5 nm) and a polyethylene filter (pore size 1 nm), and filtered to obtain a solution.

[0214] Examples 2-2 to 2-4, Comparative Examples 2-2 to 2-4 Various polymer solutions were prepared according to the methods of the above examples, while changing the polymer and solvent. The compositions of the prepared polymer solutions are summarized in Table 3.

[0215] [Measurement of particle concentration in polymer solution] The particle number concentration (counts / mL) of particles with a particle size of 0.15 μm or more in each prepared polymer solution was compared. The measuring device used was a KS-41A manufactured by Rion Co., Ltd. The smaller the counts, the fewer particles there were in the polymer solution, indicating a higher degree of solution cleanliness. The results are also shown in Table 3.

[0216]

[0217] The results shown in Tables 1 and 2 indicate that the production method of the present invention yielded extremely low levels of residual monomers, complete removal of terminal groups derived from the RAFT agent, and narrowly dispersed polymers. It was confirmed that the polymer production method of the present invention is an effective polymer production method that overcomes both the complete removal of terminal groups and the reduction of acid-generating monomers, which were insufficient in previously proposed living radical polymerization methods. Furthermore, the results shown in Table 3 indicate that the polymer solution obtained by the production method of the present invention had a low particle number concentration in the solution and was a homogeneous, clean solution. The polymer obtained by the method of the present invention is expected to be a base polymer for resist compositions, a material with a lower risk of defects.

[0218] [3] Evaluation of Temporal Stability of Polymer Solutions The polymer solutions of Examples 2-3 and 2-4 and Comparative Examples 2-3 and 2-4 were filled into two brown glass bottles, and one bottle was stored at 5°C and the other at 40°C for two weeks. The polymer solutions stored at each temperature were then allowed to stand for 8 hours in a 23°C environment. Using a Cleantrac Lithius Pro Z manufactured by Tokyo Electron Limited, the polymer solution was coated onto a 12-inch silicon wafer substrate and baked on a hot plate at 130°C for 60 seconds to form a polymer film. The film thickness was measured using a VM-3500 optical interference film thickness measurement system manufactured by SCREEN Semiconductor Solutions Co., Ltd. Furthermore, after film thickness measurement, the wafer was developed for a total of 30 seconds by discharging a 2.38% by mass aqueous solution of tetramethylammonium hydroxide onto the wafer while rotating it using a Cleantrac Lithius Pro Z. The alkaline solution was then rinsed off with water, and the wafer was spun at high speed to remove the water. The film thickness of the polymer film after development was then measured, and the film thickness variation before and after development was observed. The film thickness results are shown in Table 4.

[0219]

[0220] For the polymers of the Examples with high terminal conversion efficiencies, the difference in film thickness before and after development did not change even when the storage temperature was 40°C, but for the polymers of the Comparative Examples with low terminal conversion efficiencies, the difference in film thickness was large when stored at 40°C. In the polymer solution stored at 40°C, dissociation accompanied by decomposition of functional groups derived from the RAFT terminals progressed from the polymer terminals, generating organic acid components in the polymer solution. These components likely decomposed the acid-labile groups of the polymer, promoting its solubility in the alkaline developer. The results shown in Table 4 confirm that polymers with high terminal conversion efficiencies have excellent stability over time.

[0221] FIG. 1 shows the results of HPLC analysis after completion of each step in Examples 1-3. The bottom row in FIG. 1 is a chromatogram obtained by calculating the detection sensitivity ratio of each monomer by HPLC (column: ODS, mobile phase: water / acetonitrile 80:20→1:99, UV 220 nm detector) of a standard sample prepared by mixing 0.20 g of monomer MA-5, 0.20 g of monomer MB-4, and 0.10 g of MC-3 used in the polymer production of Examples 1-3, and 0.20 g of 3-hydroxy-1-adamantyl methacrylate as an internal standard. The second row from the bottom is a chromatogram obtained by HPLC analysis of the polymerization solution after completion of the reaction in step (1) in the polymer production method of the present invention, to which the internal standard was added in an amount equivalent to 200 ppm relative to the total amount of all charged monomers. The second chromatogram from the top is a chromatogram obtained by HPLC analysis of a polymer solution obtained after completion of the reaction in step (2) in the method for producing a polymer of the present invention, to which the internal standard substance was added in an amount equivalent to 200 ppm relative to the total amount of all charged monomers. The top chromatogram is a chromatogram obtained by HPLC analysis of a powder sample of the polymer obtained after crystallization purification in step 3 in the method for producing a polymer of the present invention, to which the internal standard substance was added in an amount equivalent to 200 ppm relative to the powder.

Claims

A method for producing a polymer comprising a repeating unit (A) derived from a monomer (A) having a structure that generates an acid upon exposure, represented by any one of the following formulas (A1) to (A6), a repeating unit (B) derived from a monomer (B) having a phenolic hydroxy group, represented by the following formula (B1), and a repeating unit (C) derived from a monomer (C) that decomposes under the action of an acid, (1) A step of polymerizing raw material monomers including monomer (A), monomer (B), and monomer (C) in a solution by living radical polymerization using a radical initiator and a reversible addition-fragmentation chain transfer agent (RAFT agent) to obtain a polymer P-1 having, at the end of its main chain, a terminal structure selected from a structure represented by the following formula (X-1) and a structure represented by the following formula (X-2) derived from the RAFT agent: (2) after the step (1), a radical generator and a thiol compound are added to a solution containing the polymer P-1, and the mixture is heated to remove the terminal structure from the main chain of the polymer P-1, thereby obtaining the polymer P; and (3) After step (2), a step of purifying the polymer P by precipitating the polymer P as a solid by mixing the solution containing the polymer P with a poor solvent. A manufacturing method comprising: (In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 1 , R 2 and R 3 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 1 and R 2 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. X 1 are each independently a single bond or a phenylene group. X 2 are each independently *-C(=O)-O-X 21 -, *-C(=O)-NH-X 21 - or *-O-X 21 - is. X 21 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain at least one selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. X 3 each independently represents a single bond, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, or *-C(=O)-O-X 31 - is. X 31 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. X 4 are each independently a single bond, -X 41 -C(=O)-O- or -O-X 41 -O-C(=O)-. X 41 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom. X 5 represents a single bond, a methylene group, an ethylene group, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, *-C(=O)-O-X 51 -, *-C(=O)-N(H)-X 51 - or *-O-X 51 - is. X 51 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. * represents a bond to a carbon atom in the main chain. X 6 represents a single bond, a methylene group, an ethylene group, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, *-C(=O)-O-X 61 -, *-C(=O)-N(H)-X 61 - or *-O-X 61 - is. X 61 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. * indicates a bond to a carbon atom in the main chain. L A1 are each independently a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond, or a carbamate bond. Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. 5 and Rf 6 cannot simultaneously become a hydrogen atom. M - are each independently a non-nucleophilic counterion. A + are each independently an onium cation. 　 a and b are each independently 0, 1, 2, or 3. (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 11 is a saturated hydrocarbyl group having 1 to 6 carbon atoms which may contain a halogen atom or at least one selected from an ether bond and a carbonyl group. L B1 is a single bond, a carbonyloxy group, or an amide group. L B2 is a single bond, or an alkanediyl group having 1 to 7 carbon atoms which may contain at least one bond selected from an ether bond and a carbonyl group. c1 is an integer that satisfies 0≦c1≦5+2(c3)−c2. 　 c2 is 1, 2, 3, 4 or 5. 　 c3 is 0, 1 or 2. (In the formula, R X1 and R X2 are each independently a saturated hydrocarbyl group having 2 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, which may contain a heteroatom. The dashed line represents a bond to a carbon atom in the polymer main chain.

2. The method for producing a polymer according to claim 1, wherein in step (1), the amounts of the monomer (A), the monomer (B), and the monomer (C) remaining in the obtained polymer P-1 solution are less than 2% by mass, less than 1% by mass, and less than 2% by mass, respectively, based on the total mass of all the charged monomers.

2. The method for producing a polymer according to claim 1, wherein the thiol compound used in the step (2) is a compound represented by the following formula (SH-1) or (SH-2): (In the formula, R SH1 is a hydrocarbylene group having 1 to 3 carbon atoms. R SH2 is an aliphatic hydrocarbyl group having 4 to 8 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, or an aryl group having 6 to 18 carbon atoms, which may contain a heteroatom. R SH3 is a saturated hydrocarbyl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, or an aryl group having 6 to 18 carbon atoms, which may contain a heteroatom.

2. The method for producing a polymer according to claim 1, wherein in step (2), the amounts of the monomer (A), the monomer (B), and the monomer (C) remaining in the polymer solution obtained are less than 0.05% by mass, less than 0.01% by mass, and less than 0.05% by mass, respectively, based on the total mass of all the charged monomers.

2. The method for producing a polymer according to claim 1, wherein the molar ratio of the structure selected from the structure represented by formula (X-1) and the structure represented by formula (X-2) contained in the polymer is each less than 1%.

2. The method for producing a polymer according to claim 1, wherein in step (1), the monomer (A), the monomer (B), the monomer (C), the radical initiator, and the RAFT agent are mixed to form a single solution, and then the resulting solution is heated to carry out living radical polymerization.

2. The method for producing a polymer according to claim 1, wherein in step (1), the monomer (A), the monomer (B), the monomer (C) and the radical initiator are prepared as one or each of independent solutions, and the resulting solution is added to a preheated RAFT agent solution to carry out living radical polymerization.

2. The method for producing a polymer according to claim 1, wherein in step (1), the amount of the radical initiator charged is 0.5 to 5 mol and the amount of the RAFT agent charged is 0.5 to 20 mol, relative to 100 mol of the total amount of the monomers charged. A method for producing a polymer solution, comprising dissolving the polymer obtained by the method according to any one of claims 1 to 8 in a solvent containing at least propylene glycol monomethyl ether acetate, and then filtering the resulting solution using a filter. 　 A polymer comprising a repeating unit (A) derived from a monomer (A) having a structure that generates acid upon exposure, which is represented by any of the following formulas (A1) to (A6), a repeating unit (B) derived from a monomer (B) having a phenolic hydroxy group, which is represented by the following formula (B1), and a repeating unit (C) derived from a monomer (C) that decomposes under the action of an acid, A polymer in which the residual amount of monomer (A) contained in the polymer is 0.05% by mass or less, the residual amount of monomer (B) is 0.01% by mass or less, the residual amount of monomer (C) that decomposes under the action of acid is 0.05% by mass or less, and the polydispersity is 1.5 or less. (In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 1 , R 2 and R 3 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 1 and R 2 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. X 1 are each independently a single bond or a phenylene group. X 2 are each independently *-C(=O)-O-X 21 -, *-C(=O)-NH-X 21 - or *-O-X 21 - is. X 21 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain at least one selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. X 3 each independently represents a single bond, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, or *-C(=O)-O-X 31 - is. X 31 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. X 4 are each independently a single bond, -X 41 -C(=O)-O- or -O-X 41 -O-C(=O)-. X 41 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom. X 5 represents a single bond, a methylene group, an ethylene group, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, *-C(=O)-O-X 51 -, *-C(=O)-N(H)-X 51 - or *-O-X 51 - is. X 51 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. * represents a bond to a carbon atom in the main chain. X 6 represents a single bond, a methylene group, an ethylene group, a phenylene group which may be substituted with a halogen atom, a naphthylene group which may be substituted with a halogen atom, *-C(=O)-O-X 61 -, *-C(=O)-N(H)-X 61 - or *-O-X 61 - is. X 61 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group which may be substituted with a halogen atom, or a naphthylene group which may be substituted with a halogen atom, and the aliphatic hydrocarbylene group may contain at least one bond selected from a carbonyl group, an ester bond, an ether bond, and a hydroxy group. * indicates a bond to a carbon atom in the main chain. L A1 are each independently a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond, or a carbamate bond. Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. 5 and Rf 6 cannot simultaneously become a hydrogen atom. M - are each independently a non-nucleophilic counterion. A + are each independently an onium cation. 　 a and b are each independently 0, 1, 2, or 3. (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 11 is a saturated hydrocarbyl group having 1 to 6 carbon atoms which may contain a halogen atom or at least one selected from an ether bond and a carbonyl group. L B1 is a single bond, a carbonyloxy group, or an amide group. L B2 is a single bond, or an alkanediyl group having 1 to 7 carbon atoms which may contain at least one bond selected from an ether bond and a carbonyl group. c1 is an integer that satisfies 0≦c1≦5+2(c3)−c2. 　 c2 is 1, 2, 3, 4 or 5. 　 c3 is 0, 1 or 2.

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