Method for producing polymer, and method for producing radiation-sensitive or actinic ray-sensitive resin composition

Abstract

To provide: a method for producing a polymer that enables the production of a desired polymer with high purity and high efficiency, which, when applied to a radiation-sensitive or actinic ray-sensitive resin composition, realizes a composition excellent in resolution and LWR performance particularly in the formation of ultra-fine patterns (e.g., with a line width or space width of 25 nm or less); and a method for producing a radiation-sensitive or actinic ray-sensitive resin composition.SOLUTION: A method for producing a polymer comprises a step of polymerizing a monomer (a) represented by general formula (I) described in the specification and a monomer (b) different from the monomer (a), where, in the polymerization step, a polymerization inhibitor is included in an amount from 10 mass ppm to 10000 mass ppm inclusive base on the mass of the monomer (a) in the reaction solution. Also provided is a method for producing a radiation-sensitive or actinic ray-sensitive resin composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a polymer, and a method for producing an actinic ray-sensitive or radiation-sensitive resin composition. [Background technology]

[0002] After resists for KrF excimer laser (248 nm), a pattern formation method using chemical amplification has been used to compensate for the decrease in sensitivity due to light absorption. For example, in a positive-type chemical amplification method, a photoacid generator contained in an exposed portion is decomposed by light irradiation to generate an acid. Then, in a post-exposure bake (PEB) process or the like, the generated acid catalyzes the alkali-insoluble group of the resin contained in the actinic ray-sensitive or radiation-sensitive resin composition to an alkali-soluble group, thereby changing the solubility in a developer. Then, development is performed using, for example, a basic aqueous solution. This removes the exposed portion to obtain a desired pattern. In order to miniaturize semiconductor elements, the wavelength of exposure light sources has become shorter and the numerical aperture (NA) of projection lenses has become higher, and currently, exposure machines using an ArF excimer laser with a wavelength of 193 nm as a light source have been developed. In addition, pattern formation methods using extreme ultraviolet light (EUV light: Extreme Ultraviolet) and electron beams (EB: Electron Beam) as light sources are also being considered in recent years. Under these circumstances, various configurations have been proposed as actinic ray-sensitive or radiation-sensitive resin compositions. Recently, resin compositions containing a resin whose main chain is decomposed or cleaved by exposure to light have become known as compositions capable of achieving ultrafine patterns, and efficient methods for producing such resins whose main chain is decomposed or cleaved have also been investigated.

[0003] For example, Patent Document 1 describes a method for producing a copolymer having an α-alkylstyrene unit content of 30 mol % or more and 70 mol % or less and an α-chloroacrylic acid ester unit content of 30 mol % or more and 70 mol % or less, the method including a step of solution polymerizing a monomer composition containing an α-alkylstyrene and an α-chloroacrylic acid ester, and using a ketone as a polymerization solvent for the solution polymerization. Furthermore, as an example of a resin composition containing a resin whose main chain is decomposed or cleaved by exposure to light, Patent Document 2 describes an organic resin composition that contains a polymer whose main chain is cleaved by absorbing deep ultraviolet light, and a polymerization inhibitor, the content of the polymerization inhibitor being 0.07 parts by mass or more and 0.60 parts by mass or less per 100 parts by mass of the polymer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-171822 A [Patent Document 2] JP 2020-045471 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the miniaturization of patterns formed using EUV or electron beams has progressed, and further improvement in the performance of actinic ray- or radiation-sensitive resin compositions is required. In particular, improvement in resolution and line width roughness (LWR) performance is strongly required. LWR performance refers to the ability to reduce the LWR of a pattern.

[0006] However, as a result of the investigations by the present inventors, in the method for producing a copolymer described in Patent Document 1, when a monomer containing an α-alkylstyrene and an α-chloroacrylic acid ester is copolymerized, homopolymerization of the α-chloroacrylic acid ester tends to proceed, making it difficult to stably produce a desired copolymer. As a result, it was found that further improvements in resolution and LWR performance are expected, particularly when an ultrafine pattern is to be formed using an actinic ray- or radiation-sensitive resin composition containing the obtained copolymer. Patent Document 2 does not provide a detailed description of a method for producing the polymer used in the organic resin composition.

[0007] Therefore, an object of the present invention is to provide a method for producing a polymer, which is capable of producing a desired polymer with high purity and high efficiency, and which, when applied to an actinic ray-sensitive or radiation-sensitive resin composition, can provide a composition having excellent resolution and LWR performance, particularly in the formation of an ultrafine pattern (e.g., a line width or space width of 25 nm or less). [Means for solving the problem]

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

[0009] [1] A method for producing a polymer, comprising a step of polymerizing a monomer (a) represented by the following general formula (I) with a monomer (b) different from the above monomer, The method for producing a polymer, wherein the polymerization step comprises containing from 10 ppm by mass to 10,000 ppm by mass of a polymerization inhibitor relative to the monomer (a) in the reaction liquid.

[0010] [ka]

[0011] In general formula (I), X represents a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group or a halogenated alkyl group. L 1 is -O- or -NR X - stands for R X represents a hydrogen atom or a monovalent organic group. R 1 represents a monovalent organic group. Ra represents a hydrogen atom or a monovalent organic group. 1 and Ra may be bonded to each other to form a ring.

[0012] [2] The method for producing a polymer according to [1], wherein the monomer (b) is represented by the following general formula (II):

[0013] [ka]

[0014] In general formula (II), Rb represents a hydrogen atom or a monovalent organic group. R 2 represents an alkyl group, a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group or a halogenated alkyl group. Ar represents an aromatic ring group. R 3 represents an alkyl group, an alkoxy group, an acyloxy group, a halogen atom, a hydroxy group, a carboxy group, or a halogenated alkyl group. p is an integer between 0 and 5. 3 When multiple R are present, they may be the same or different. 3 and Rb may be bonded to each other to form a ring.

[0015] [3] The method for producing a polymer according to [1] or [2], wherein the polymerization step further comprises a polymerization initiator in the reaction solution. [4] The method for producing a polymer according to any one of [1] to [3], wherein in the polymerization step, the reaction liquid contains at least one solvent selected from the group consisting of ketones, esters, and ethers. [5] The method for producing a polymer according to any one of [1] to [4], wherein, in the polymerization step, the reaction liquid contains an aqueous surfactant solution.

[0016] [6] The method for producing a polymer according to any one of [1] to [5], wherein, in the above general formula (I), X is a chlorine atom. [7] In the above general formula (II), R 2 wherein the group is an alkyl group. [8] The method for producing a polymer according to any one of [1] to [7], wherein the polymerization step is carried out at a polymerization temperature of 10° C. or higher and 90° C. or lower.

[0017] [9] The method for producing a polymer according to any one of [1] to [8], wherein the polymer has a weight average molecular weight of 5,000 or more and 1,000,000 or less.

[10] The method for producing a polymer according to any one of [1] to [9], wherein the amount of the polymerization initiator is 5 mass % or less based on the total amount of the monomers.

[11] The method for producing a polymer according to any one of [1] to

[10] , wherein the polymer is a polymer for use in an actinic ray-sensitive or radiation-sensitive resin composition.

[0018]

[12] A step of producing a polymer by the production method according to any one of [1] to

[10] ; A method for producing an actinic ray-sensitive or radiation-sensitive resin composition, comprising the step of mixing the above polymer with a solvent.

[13] The method for producing an actinic ray-sensitive or radiation-sensitive resin composition according to

[12] , wherein at least one ionic compound is further mixed in the mixing step.

[14] The method for producing an actinic ray-sensitive or radiation-sensitive resin composition according to

[13] , wherein the ionic compound is at least one selected from a sulfonium salt and an iodonium salt. Effect of the Invention

[0019] According to the present invention, it is possible to provide a method for producing a polymer, which is capable of producing a desired polymer with high purity and high efficiency, and which, when applied to an actinic ray-sensitive or radiation-sensitive resin composition, can give a composition excellent in resolution and LWR performance, particularly in the formation of an ultrafine pattern (for example, a line width or space width of 25 nm or less). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The present invention will be described in detail below. The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In the present specification, the notation of groups (atomic groups) that does not indicate whether they are substituted or unsubstituted includes both unsubstituted and substituted groups, unless it is contrary to the spirit of the present invention. For example, an "alkyl group" includes not only an alkyl group that does not have a substituent (unsubstituted alkyl group), but also an alkyl group that has a substituent (substituted alkyl group). In addition, an "organic group" in the present specification refers to a group that contains at least one carbon atom. Unless otherwise specified, the substituent is preferably a monovalent substituent. In this specification, "actinic rays" or "radiation" refers to, for example, the bright line spectrum of a mercury lamp, far ultraviolet rays represented by excimer lasers, extreme ultraviolet rays (EUV: Extreme Ultraviolet), X-rays, and electron beams (EB: Electron Beam), etc. In this specification, "light" refers to actinic rays or radiation. In this specification, unless otherwise specified, "exposure" includes not only exposure to the emission line spectrum of a mercury lamp, far ultraviolet light represented by an excimer laser, extreme ultraviolet light (EUV light: Extreme Ultraviolet), X-rays, and the like, but also drawing with particle beams such as electron beams (EB) and ion beams. In this specification, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit. The bonding direction of the divalent group described in this specification is not limited unless otherwise specified. For example, when Y is -COO- in a compound represented by the formula "XYZ", Y may be -CO-O- or -O-CO-. In addition, the above compound may be "X-CO-OZ" or "XO-CO-Z".

[0021] In this specification, the weight average molecular weight (Mw), number average molecular weight (Mn), and dispersity (also referred to as molecular weight distribution) (Mw / Mn) of a resin are defined as polystyrene-equivalent values ​​measured using a Gel Permeation Chromatography (GPC) apparatus (HLC-8120GPC manufactured by Tosoh Corporation) (solvent: tetrahydrofuran, flow rate (sample injection amount): 10 μL, column: TSK gel Multipore HXL-M manufactured by Tosoh Corporation, column temperature: 40° C., flow rate: 1.0 mL / min, detector: refractive index detector).

[0022] In this specification, the acid dissociation constant (pKa) refers to the pKa in an aqueous solution, and specifically, is a value calculated based on a database of Hammett's substituent constants and known literature values ​​using the following software package 1. All pKa values ​​described in this specification are values ​​calculated using this software package.

[0023] Software package 1: Advanced Chemistry Development (ACD / Labs) Software V8.14 for Solaris (1994-2007 ACD / Labs).

[0024] On the other hand, pKa can also be calculated by molecular orbital calculations. A specific method for this is to calculate the pKa of H in aqueous solution based on the thermodynamic cycle. + One method is to calculate the dissociation free energy. + The method of calculating the dissociation free energy can be, for example, calculated by DFT (density functional theory), but various other methods have been reported in the literature, and the method is not limited to these. There are several software programs that can perform DFT, such as Gaussian16.

[0025] As described above, the pKa in this specification refers to a value calculated using the software package 1 based on the database of Hammett's substituent constants and known literature values. However, when the pKa cannot be calculated by this method, a value obtained by Gaussian 16 based on DFT (density functional theory) is used. In addition, the pKa in this specification refers to the "pKa in an aqueous solution" as described above, but when the pKa in an aqueous solution cannot be calculated, the "pKa in a dimethyl sulfoxide (DMSO) solution" will be used.

[0026] In this specification, examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0027] In this specification, the term "solid content" refers to components that form an actinic ray-sensitive or radiation-sensitive film and does not include solvents. In addition, any component that forms an actinic ray-sensitive or radiation-sensitive film is considered to be a solid content even if it is in a liquid state.

[0028] [Polymer manufacturing method] The method for producing a polymer of the present invention is a method for producing a polymer, comprising a step of polymerizing a monomer (a) represented by the following general formula (I) and a monomer (b) different from the above monomer, In the polymerization step, the reaction liquid contains 10 ppm by mass or more and 10,000 ppm by mass or less of a polymerization inhibitor relative to the monomer (a) in the reaction liquid.

[0029] [ka]

[0030] In general formula (I), X represents a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group or a halogenated alkyl group. L 1 is -O- or -NR X - stands for R X represents a hydrogen atom or a monovalent organic group. R 1 represents a monovalent organic group. Ra represents a hydrogen atom or a monovalent organic group. 1 and Ra may be bonded to each other to form a ring.

[0031] The present inventors presume that the reason why the method for producing a polymer of the present invention enables a desired polymer to be produced with high purity and high efficiency is as follows. First, the present inventors have found, as a result of intensive research, that the monomer (a) represented by the above general formula (I) is a compound with very high polymerization reactivity due to the presence of the group represented by X, and that in the process of copolymerization of the monomer (a) represented by the general formula (I) with a monomer (b) different from the monomer (a), polymerization between the monomers (a) may be facilitated. It was then presumed that the generation of a homopolymer of the monomer (a) in the finally obtained polymerization product leads to a decrease in the purity of the copolymer having the desired copolymerization ratio. In the present invention, as described above, in the copolymerization of the monomer (a) represented by the general formula (I) and the monomer (b) different from the monomer (a), the polymerization inhibitor is intentionally made to exist in the reaction solution in the above-mentioned predetermined amount range. As a result, the desired copolymer can be obtained with high purity without inhibiting the polymerization of the copolymer, and further, such a copolymer can be produced with high efficiency. Furthermore, when the polymer obtained by the method for producing a polymer of the present invention was applied to an actinic ray- or radiation-sensitive resin composition, it was surprisingly found that the resolution and LWR performance were very excellent, particularly in the formation of ultrafine patterns (e.g., line width or space width of 25 nm or less). This is believed to be because the presence of a polymerization inhibitor in the reaction system suppresses the production of a homopolymer of monomer (a), increasing the purity of the desired copolymer in the final polymerization product, and therefore suppressing the inclusion of the homopolymer of monomer (a) as an impurity in the actinic ray- or radiation-sensitive resin composition.

[0032] [Polymerization process] First, the process for producing the polymer of the present invention will be described. The method for producing a polymer of the present invention is a method for producing a polymer, comprising a step of polymerizing a monomer (a) represented by the above general formula (I) and a monomer (b) different from the above monomer, In the polymerization step, the reaction solution contains a polymerization inhibitor in an amount of 10 ppm by mass or more and 10,000 ppm by mass or less relative to the monomer (a) in the reaction solution.

[0033] <Monomer> The monomers (a) and (b) used in the polymerization step will be described below.

[0034] (Monomer (a)) The monomer (a) is represented by the above general formula (I).

[0035] In the above general formula (I), X represents a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group or a halogenated alkyl group.

[0036] Examples of the halogen atom represented by X include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a chlorine atom, a bromine atom, or an iodine atom being preferred, and a chlorine atom being more preferred.

[0037] The alkyl group in the alkylsulfonyl group represented by X includes linear or branched alkyl groups having 1 to 6 carbon atoms, and a methyl group or an ethyl group is preferable.

[0038] Examples of the alkyl group in the alkoxy group represented by X include the alkyl groups in the alkylsulfonyl group described above, and preferred examples are the same.

[0039] Examples of the alkyl group in the alkyl ester group (alkylcarbonyloxy group) represented by X include the alkyl groups in the alkylsulfonyl group described above, and preferred examples are the same.

[0040] Examples of the alkyl group in the halogenated alkyl group represented by X include the alkyl group in the alkylsulfonyl group described above, and the preferred examples are the same. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is more preferred.

[0041] Examples of the alkyl group in the acyl group (alkylcarbonyl group or arylcarbonyl group) represented by X include the alkyl groups in the alkylsulfonyl group described above, and preferred examples are also the same. Examples of the aryl group include aryl groups having 6 to 12 carbon atoms, and a phenyl group is preferred.

[0042] If possible, the above group represented by X may further have a substituent. Examples of the substituent include the substituent T described below.

[0043] From the viewpoint of efficiently obtaining a copolymer useful as a main-chain decomposition-type resin contained in an actinic ray-sensitive or radiation-sensitive resin composition, X preferably represents a halogen atom, more preferably a chlorine atom, a bromine atom, or an iodine atom, and further preferably a chlorine atom.

[0044] R X The monovalent organic group is not particularly limited, and examples thereof include monovalent organic groups having a carbon number of 1 to 20. As the monovalent organic group, an alkyl group or a cycloalkyl group is preferable. The alkyl group may be either linear or branched, and examples thereof include alkyl groups having 1 to 20 carbon atoms, preferably alkyl groups having 1 to 10 carbon atoms, and more preferably alkyl groups having 1 to 6 carbon atoms. The cycloalkyl group may be monocyclic or polycyclic, and is preferably a cycloalkyl group having 5 to 20 carbon atoms, more preferably a cycloalkyl group having 5 to 15 carbon atoms. Furthermore, each of the above groups may further have a substituent, if possible. R X preferably represents a hydrogen atom.

[0045] In the above general formula (I), R 1 R represents a monovalent organic group. 1 The monovalent organic group represented by the formula (I) is not particularly limited, and examples thereof include the groups exemplified as the organic group W below.

[0046] (Organic group W) Examples of the organic group W include an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a cycloalkynyl group, an aryl group, a heteroaryl group, an aralkyl group, a cyano group, an alkoxy group, an aryloxy group, a heterocyclic oxy group, an acyl group (an alkylcarbonyl group or an arylcarbonyl group), an acyloxy group (an alkylcarbonyloxy group or an arylcarbonyloxy group), a carbamoyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, an alkyl or arylsulfinyl group, an alkyl or arylsulfonyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, an aryl or heterocyclic azo group, a sulfonamide group, an imido group, an acylamino group, a carbamoyl group, and a lactone group. In addition, each of the above groups may further have a substituent, if possible. For example, an alkyl group which may have a substituent is also included as one form of the organic group W. The above-mentioned substituent is not particularly limited, and examples thereof include one or more groups among the groups shown as the above-mentioned organic group W, a halogen atom, a nitro group, a primary to tertiary amino group, a phosphino group, a phosphinyl group, a phosphinyloxy group, a phosphinylamino group, a phosphono group, a silyl group, a hydroxy group, a carboxy group, a sulfonic acid group, and a phosphoric acid group (hereinafter, these are referred to as "substituents T"). The organic group W has 1 to 20 carbon atoms, for example. The organic group W has 1 to 30 atoms other than hydrogen atoms, for example.

[0047] The alkyl group exemplified as the organic group W preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms. The alkyl group may be either linear or branched. Examples of the alkyl group include linear or branched alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a t-butyl group, and an n-hexyl group. In the alkyl group which may have a substituent, the substituent which the alkyl group may have is not particularly limited, and examples thereof include the groups exemplified for the substituent T above. In addition, in order to improve the interactivity with ionic compounds (e.g., photodecomposable onium salt compounds) which may be contained in the actinic ray-sensitive or radiation-sensitive resin composition and which will be described later, and to thereby improve the effects of the present invention, it is also preferable for the compound to have, as a substituent, a group which interacts with ionic compounds described later (hereinafter referred to as an "interactive group"), such as a hydroxy group (an alcoholic hydroxy group, a phenolic hydroxy group, etc.), a carboxyl group, a sulfonic acid group, an amide group, and a sulfonamide group. The phenolic hydroxyl group refers to a hydroxyl group substituted on a ring atom of an aromatic ring (aromatic hydrocarbon ring or aromatic heterocycle). The amide group is not particularly limited, but examples thereof include -C(=O)-NHR P (R P represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

[0048] As the alkyl group portion in the alkoxy group (including the alkoxy group portion in a substituent containing an alkoxy group (for example, an alkoxycarbonyloxy group)), the alkyl group portion in the aralkyl group, the alkyl group portion in the alkylcarbonyl group, the alkyl group portion in the alkylcarbonyloxy group, the alkyl group portion in the alkylthio group, the alkyl group portion in the alkylsulfinyl group, and the alkyl group portion in the alkylsulfonyl group, which are exemplified in the organic group W, the above-mentioned alkyl groups are preferable. In addition, in the alkoxy group which may have a substituent, the aralkyl group which may have a substituent, the alkylcarbonyloxy group which may have a substituent, the alkylthio group which may have a substituent, the alkylsulfinyl group which may have a substituent, and the alkylsulfonyl group which may have a substituent, examples of the substituent that the alkoxy group, the aralkyl group, the alkylcarbonyloxy group, the alkylthio group, the alkylsulfinyl group, and the alkylsulfonyl group may have include the same examples as the substituent in the alkyl group which may have a substituent.

[0049] Examples of the cycloalkyl group in the organic group W include monocyclic cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group, and polycyclic cycloalkyl groups such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group. The number of carbon atoms in the cycloalkyl group is preferably 5 to 20, and more preferably 5 to 15. In the cycloalkyl group which may have a substituent, examples of the substituent which the cycloalkyl group may have include the same as those of the substituent in the alkyl group which may have a substituent.

[0050] The alkenyl group exemplified in the organic group W may be either linear or branched. The number of carbon atoms in the alkenyl group is preferably 2 to 20. In the alkenyl group which may have a substituent, examples of the substituent which the alkenyl group may have include the same examples as the substituent in the alkyl group which may have a substituent. The number of carbon atoms in the cycloalkenyl group exemplified in the organic group W is preferably 5 to 20. In the cycloalkenyl group which may have a substituent, examples of the substituent which the cycloalkenyl group may have include the same examples as the substituent in the alkyl group which may have a substituent.

[0051] The alkynyl group exemplified in the organic group W may be either linear or branched. The number of carbon atoms in the alkynyl group is preferably 2 to 20. In the alkynyl group which may have a substituent, examples of the substituent which the alkynyl group may have include the same examples as the substituent in the alkyl group which may have a substituent. The number of carbon atoms in the cycloalkynyl group exemplified in the organic group W is preferably 5 to 20. In the cycloalkynyl group which may have a substituent, examples of the substituent which the cycloalkynyl group may have include the same examples as the substituent in the alkyl group which may have a substituent.

[0052] The aryl group exemplified as the organic group W may be either a monocyclic or polycyclic (eg, 2 to 6 rings) group, unless otherwise specified. The aryl group preferably has 6 to 15 ring atoms, and more preferably has 6 to 10 ring atoms. The aryl group is preferably a phenyl group, a naphthyl group, or an anthryl group, and more preferably a phenyl group. In the aryl group which may have a substituent, examples of the substituent which the aryl group may have include the same substituents as those in the alkyl group which may have a substituent. Among the groups exemplified for the organic group W, the aryl group moiety in a substituent containing an aryl group (for example, an aryloxy group) includes the same examples as the aryl groups exemplified for the organic group W above.

[0053] The heteroaryl group exemplified as the organic group W may be either a monocyclic or polycyclic (eg, 2 to 6 rings) group, unless otherwise specified. The number of heteroatoms contained as ring members in the heteroaryl group is, for example, 1 to 10. Examples of the heteroatom include a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom. The heteroaryl group preferably has 5 to 15 ring atoms. In the heteroaryl group which may have a substituent, examples of the substituent which the heteroaryl group may have include the same substituents as those in the alkyl group which may have a substituent.

[0054] The heterocycle exemplified in the organic group W is intended to mean a ring containing a heteroatom as a ring member atom, and unless otherwise specified, may be either an aromatic heterocycle or an aliphatic heterocycle, and may be either a monocycle or a polycycle (e.g., 2 to 6 rings, etc.). The number of heteroatoms contained in the heterocycle as ring member atoms is, for example, 1 to 10. Examples of the heteroatom include a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom. The heterocycle preferably has 5 to 15 ring atoms. In the hetero ring which may have a substituent, examples of the substituent which the hetero ring may have include the same substituents as those in the alkyl group which may have a substituent.

[0055] The lactone group exemplified as the organic group W is preferably a 5- to 7-membered lactone group, and more preferably a 5- to 7-membered lactone ring to which another ring structure is condensed to form a bicyclo structure or a spiro structure. In the lactone group which may have a substituent, examples of the substituent which the lactone group may have include the same substituents as those in the alkyl group which may have a substituent.

[0056] R 1 Among these, an alkyl group, a cycloalkyl group, or an aryl group is preferable, and an alkyl group having 1 to 6 carbon atoms, a cyclohexyl group, or a phenyl group is more preferable.

[0057] The monovalent organic group of Ra is not particularly limited, but may be, for example, an alkyl group. The alkyl group may be either linear or branched, and examples thereof include alkyl groups having 1 to 20 carbon atoms, preferably alkyl groups having 1 to 10 carbon atoms, and more preferably alkyl groups having 1 to 6 carbon atoms. Ra preferably represents a hydrogen atom.

[0058] R 1 and Ra may be bonded to each other to form a ring. R 1 The ring formed by bonding with Ra is not particularly limited, and may be either a monocyclic ring or a polycyclic ring. The ring may contain heteroatoms such as oxygen atoms, nitrogen atoms, and sulfur atoms, and / or carbonyl carbon atoms as ring members. Of these, the ring is preferably a 5- or 6-membered ring.

[0059] From the viewpoint of usefulness as a resin contained in the actinic ray-sensitive or radiation-sensitive resin composition, the monomer (a) is preferably represented by the following general formula (I-1).

[0060] [ka]

[0061] In general formula (I-1), X 1 represents a halogen atom, R 1 represents a monovalent organic group.

[0062] X 1 Examples of the halogen atom represented by include the halogen atom represented by X in the general formula (I), and preferred examples are also the same. R 1 R in general formula (I) 1 The same applies to preferred examples.

[0063] Specific examples of the monomer (a) represented by general formula (I) are given below, but the monomer (a) is not limited thereto.

[0064] [ka]

[0065] [ka]

[0066] The monomer (a) may be used alone or in combination of two or more kinds. The content of the monomer (a) used in the polymerization step is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 40 mol% or more, based on the total amount of the monomers. The upper limit is, for example, preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 80 mol% or less, and particularly preferably 60 mol% or less, based on the total amount of the monomers. As described above, the monomer (a) may be used alone or in combination of two or more. When two or more types are used, the total content is preferably within the above-mentioned preferred content range.

[0067] <Monomer (b)> The monomer (b) is a compound different from the above monomer (a). The monomer (b) is preferably a compound having a lower polymerization reactivity than the monomer (a).

[0068] The monomer (b) is not particularly limited, but one of the preferred embodiments is represented by the following general formula (II).

[0069] [ka]

[0070] In general formula (II), Rb represents a hydrogen atom or a monovalent organic group. R 2 represents an alkyl group, a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group or a halogenated alkyl group. Ar represents an aromatic ring group. R 3 represents an alkyl group, an alkoxy group, an acyloxy group, a halogen atom, a hydroxy group, a carboxy group, or a halogenated alkyl group. p is an integer between 0 and 5. 3 When multiple R are present, they may be the same or different. 3 and Rb may be bonded to each other to form a ring.

[0071] The substituent of Rb is not particularly limited, but examples thereof include an alkyl group. The alkyl group may be either linear or branched, and examples thereof include alkyl groups having 1 to 20 carbon atoms, preferably alkyl groups having 1 to 10 carbon atoms, and more preferably alkyl groups having 1 to 6 carbon atoms. Rb preferably represents a hydrogen atom.

[0072] In general formula (II), R 2represents an alkyl group, a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group or a halogenated alkyl group.

[0073] R 2 Examples of the alkyl group represented by the formula (I) include linear or branched alkyl groups having 1 to 4 carbon atoms, and a methyl group is preferred. R 2 Examples of the halogen atom, cyano group, alkylsulfonyl group, alkoxy group, nitro group, acyl group, alkyl ester group, and halogenated alkyl group represented by the formula (I) above include the halogen atom, cyano group, alkylsulfonyl group, alkoxy group, nitro group, acyl group, alkyl ester group, and halogenated alkyl group represented by the formula (I) above, and preferred examples are also the same.

[0074] R 2 The above group represented by the following formula (1) may further have a substituent, if possible. Examples of the substituent include the above-mentioned substituent T.

[0075] R 2 is preferably an alkyl group, more preferably a methyl group.

[0076] The aromatic ring in the aromatic ring group of Ar includes an aromatic hydrocarbon ring or an aromatic heterocycle.

[0077] The aromatic hydrocarbon ring may be a monocyclic ring or a polycyclic ring, and preferably has 6 to 15 ring atoms, more preferably 6 to 10 ring atoms. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, etc. Among these, a benzene ring or a naphthalene ring is preferable, and a benzene ring is more preferable.

[0078] The aromatic heterocycle may be a monocycle or a polycycle, and preferably has 5 to 15 ring atoms. Examples of the heterocyclic ring having aromaticity include a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, a pyridine ring, an indole ring, a benzodiazole ring, and a carbazole ring.

[0079] The aromatic ring group of Ar is R 3 It may have a substituent other than the above.

[0080] In general formula (II), R 3 represents an alkyl group, an alkoxy group, an acyloxy group, a halogen atom, a hydroxy group, a carboxy group, or a halogenated alkyl group.

[0081] R 3 Examples of the alkyl group and alkoxy group represented by the formula (I) include the alkyl group and alkoxy group as the organic group W described above, and preferred examples are also the same. R 3 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is more preferable. R 3 Examples of the alkyl group in the acyloxy group (alkylcarbonyloxy group or arylcarbonyloxy group) represented by the formula (I) include the alkyl groups described above as the organic group W, and preferred examples are the same. Examples of the aryl group include the alkyl groups described above as the organic group W, and preferred examples are the same. R 3 The alkyl group in the halogenated alkyl group represented by the formula: 3 Preferred examples are also the same. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is more preferred.

[0082] R 3 The above group represented by the following formula (1) may further have a substituent, if possible. Examples of the substituent include the above-mentioned substituent T.

[0083] R 3is preferably a hydroxy group, a carboxy group, or an alkoxy group having 1 to 6 carbon atoms, and is more preferably a hydroxy group or a carboxy group from the viewpoint of improving the interactivity with an ionic compound (e.g., a photodecomposable onium salt compound) which may be contained in the actinic ray-sensitive or radiation-sensitive resin composition and which will be described later.

[0084] In formula (II), p is an integer of 0 or more and 5 or less, an integer of 0 to 3 is preferable, and an integer of 1 to 2 is more preferable.

[0085] R 3 and Rb may be bonded to each other to form a ring. R 3 The ring formed by bonding R to Rb is not particularly limited and may be either a monocyclic ring or a polycyclic ring. The ring may contain, as a ring member atom, a heteroatom such as an oxygen atom, a nitrogen atom, or a sulfur atom, and / or a carbonyl carbon. Of these, the ring is preferably a 5- or 6-membered ring.

[0086] In one preferred embodiment, the monomer (b) is represented by the following general formula (II-a):

[0087] [ka]

[0088] In general formula (II-a), Rb represents a hydrogen atom or a monovalent organic group. R 2 represents an alkyl group, a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group, or a halogenated alkyl group. Ar 1 represents an aromatic ring group. R 3a represents an alkyl group, an alkoxy group, a halogen atom, a hydroxy group, a carboxy group, or a halogenated alkyl group. R 4 represents an acyl group. pa is an integer between 0 and 4. 3a When multiple are present, they may be the same or different. pb is an integer between 1 and 5. 4 When multiple are present, they may be the same or different. The sum of pa and pb is 1 to 5. R 3a and Rb may be bonded to each other to form a ring.

[0089] In general formula (II-a), Rb, R 2 respectively represent Rb and R in general formula (II). 2 The same applies to preferred examples.

[0090] Ar 1 The aromatic ring in the aromatic ring group includes an aromatic hydrocarbon ring or an aromatic heterocycle. The aromatic hydrocarbon ring may be a monocyclic ring or a polycyclic ring, and preferably has 6 to 15 ring atoms, more preferably 6 to 10 ring atoms. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, etc. Among these, a benzene ring or a naphthalene ring is preferable, and a benzene ring is more preferable.

[0091] The aromatic heterocycle may be a monocycle or a polycycle, and preferably has 5 to 15 ring atoms. Examples of the heterocyclic ring having aromaticity include a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, a pyridine ring, an indole ring, a benzodiazole ring, and a carbazole ring.

[0092] R 3a The alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as have the same meaning as the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group in general formula (II), and preferred examples are also the same.

[0093] pa is an integer of 0 or more and 4 or less. pa is preferably an integer of 0 or more and 2 or less. pb is an integer of 1 or more and 5 or less. pb is preferably an integer of 1 or more and 2 or less. The sum of pa and pb is 1 or more and 5 or less. The sum of pa and pb is preferably 1 or more and 3 or less.

[0094] R 3a and Rb may be bonded to each other to form a ring. R 3a The ring formed by bonding R to Rb is not particularly limited and may be either a monocyclic ring or a polycyclic ring. The ring may contain, as a ring member atom, a heteroatom such as an oxygen atom, a nitrogen atom, or a sulfur atom, and / or a carbonyl carbon. Of these, the ring is preferably a 5- or 6-membered ring.

[0095] Specific examples of the monomer (b) are given below, but are not limited thereto, in which Me represents a methyl group and Ac represents an acetyl group.

[0096] [ka]

[0097] [ka]

[0098] [ka]

[0099] The monomer (b) may be used alone or in combination of two or more kinds.

[0100] <Polymerization inhibitor (B)> In the polymerization step, the reaction liquid contains 10 mass ppm to 10,000 mass ppm of a polymerization inhibitor (hereinafter also referred to as polymerization inhibitor (B)) relative to the monomer (a) (when multiple types are used, the total amount). In the method for producing a polymer of the present invention, the polymerization inhibitor (B) is added for the purpose of suppressing polymerization of monomers (a) having high polymerization activity with each other.

[0101] Polymerization inhibitors are compounds that are added to substances that are susceptible to polymerization reactions due to the effects of light or heat to inhibit the polymerization reaction. Polymerization inhibitors are classified into two types based on their structure. 1) Compounds that exist as stable radicals 2) Compounds that easily react with radicals present in the polymerization system to turn into stable radicals.

[0102] Representative compounds of 1) include free radical compounds such as TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl, O-radical) and 1,1-Diphenyl-2-picrylhydrazyl Free Radical (N-radical). Representative compounds of 2) include hydroquinone (HQ), methoxyhydroquinone (MEHQ), phenolic compounds such as bisphenol A and dibutylhydroxytoluene (BHT), amine compounds such as phenothiazine, nitro compounds, and nitroso compounds. The nitro compounds and nitroso compounds are preferably aromatic nitro compounds and aromatic nitroso compounds. The aromatic ring contained in the aromatic nitro compounds and aromatic nitroso compounds is preferably an aromatic hydrocarbon ring. The number of carbon atoms in the ring of the aromatic ring is preferably 6 to 20, more preferably 6 to 15. The aromatic ring may have a substituent, and examples of the substituent include an alkyl group, a cycloalkyl group, and a hydroxyl group. Specific examples include 3,5-dinitrotoluene and 2,4-dinitrosoresorcinol.

[0103] The polymerization inhibitor (B) used in the production method of the present invention is preferably at least one selected from the group consisting of free radical compounds, phenolic compounds, amine compounds, nitro compounds and nitroso compounds, and more preferably at least one selected from the group consisting of free radical compounds and phenolic compounds.

[0104] As the free radical compound, TEMPO, or a TEMPO derivative such as 4-hydroxyTEMPO, 4-benzoylTEMPO, or 1,1-diphenyl-2-picrylhydrazyl free radical is preferred, with TEMPO or 4-hydroxyTEMPO being more preferred. Examples of the phenol compound include monohydric phenol derivatives such as hydroquinone (HQ), methoxyhydroquinone (MEHQ), dibutylhydroxytoluene (BHT), etc., polyhydric phenol derivatives such as t-butylcatechol, benzoquinone derivatives such as benzoquinone (BQ), which is an oxidized form of hydroquinone, and amine derivatives such as phenothiazine, among which monohydric / polyhydric phenol derivatives are more preferred, monohydric / dihydric phenol derivatives are even more preferred, and HQ, MEHQ, or BHT are particularly preferred.

[0105] The amount of the polymerization inhibitor (B) added is 10 mass ppm or more relative to the monomer (a). If it is less than 10 mass ppm, the effect of suppressing the polymerization of the monomers (a) cannot be sufficiently obtained. The amount added is preferably 100 mass ppm or more relative to the monomer (a), more preferably 500 mass ppm or more, and even more preferably 1000 mass ppm or more. The amount of the polymerization inhibitor (B) added is 10,000 ppm by mass or less relative to the monomer (a). If it exceeds 10,000 ppm by mass, the resulting copolymer may be inhibited from being made high molecular weight. The amount added is preferably 8,000 ppm by mass or less relative to the monomer (a), more preferably 6,000 ppm by mass or less, and even more preferably 4,000 ppm by mass or less. It is most preferably 1,000 ppm or more and 4,000 ppm or less.

[0106] The polymerization reaction in the polymerization step is typically radical polymerization, and may be, for example, solution polymerization, bulk polymerization, dispersion polymerization, or emulsion polymerization.

[0107] <Polymerization initiator> In the reaction in the above polymerization step, a polymerization initiator is usually further used. That is, the reaction system further contains a polymerization initiator. As the polymerization initiator, for example, a radical initiator such as an azo initiator and a peroxide is used to initiate polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. As the preferred initiator, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate), etc. are mentioned. As the peroxide, potassium persulfate, di-tert-butyl peroxide, etc. are mentioned. If desired, the initiator may be added in several portions.

[0108] In the polymerization step, the amount of the polymerization initiator is preferably 5% by mass or less relative to the total amount of the monomer. If the amount of the polymerization initiator is 5% by mass or less, the molecular weight can be extended to a desired range. The amount of the polymerization initiator is more preferably 3% by mass or less, and even more preferably 1% by mass or less. The lower limit is not particularly limited, but is usually 0.01% by mass or more.

[0109] <Solvent> When the reaction in the polymerization step is a solution polymerization, the reaction liquid in the polymerization step further contains a solvent. The solvent is not particularly limited as long as it dissolves each component, but it is preferable that the solvent contains at least one selected from the group consisting of ketones, esters, ethers, and alcohols.

[0110] Examples of ketones include methyl ethyl ketone, cyclopentanone (Cp), and cyclohexanone (XAN). Examples of esters include propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate (EL), and gamma butyrolactone (GBL). An example of the ethers is tetrahydrofuran. An example of the alcohols is propylene glycol monomethyl ether (PGME).

[0111] Of these, the solvent used in the solution polymerization is preferably cyclopentanone, cyclohexanone, PGMEA, or PGME, and more preferably cyclopentanone, PGME, or PGMEA.

[0112] These solvents may be used alone or in combination of two or more.

[0113] <Surfactant solution> When the reaction in the polymerization step is emulsion polymerization, the reaction liquid in the polymerization step preferably contains an aqueous solution of a surfactant.

[0114] Here, the surfactant used in the aqueous surfactant solution is not particularly limited, and for example, a surfactant that contains a hydrophilic group and a lipophilic group and can form micelles for emulsion polymerization can be used. Specifically, a nonionic surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant, etc. can be used.

[0115] Examples of nonionic surfactants include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene alkyl ether, polyoxyethylene myristyl ether, polyoxyethylene octyldodecyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene derivatives, polyoxyethylene polyoxypropylene glycol, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tri ... areate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tetraoleate, glycerol monostearate, glycerol monooleate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan sesquioleate, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyethylene glycol monooleate, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkylamines, alkyl alkanolamides, stearic acid monoglyceride, polyoxyethylene-polyoxypropylene block polymers, and the like.

[0116] Examples of cationic surfactants include coconut amine acetate, stearylamine acetate, lauryl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, distearyl dimethyl ammonium chloride, alkyl benzyl dimethyl ammonium chloride, hydrochlorides of primary amines such as monomethylamine, monoethylamine, and monostearylamine; hydrochlorides of secondary amines such as dimethylamine, diethylamine, and distearylamine; hydrochlorides of tertiary amines such as trimethylamine, triethylamine, and stearyl dimethylamine; hydrochlorides of ethanolamines such as monoethanolamine, diethanolamine, and triethanolamine; hydrochlorides of polyethylene polyamines such as ethylene diamine and diethylene triamine; and hydrochlorides of amines such as pyridine, morpholine, and hydrazine.

[0117] Examples of anionic surfactants include mixed fatty acid soda soap, semi-hardened beef tallow fatty acid soda soap, sodium stearate soap, semi-hardened beef tallow fatty acid potassium soap, potassium oleate soap, castor oil potassium soap, sodium lauryl sulfate, sodium higher alcohol sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium alkyl naphthalene sulfonate, sodium dialkyl sulfosuccinate, sodium alkyl diphenyl ether disulfonate, potassium alkyl phosphate, sodium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene alkyl ether sulfate, triethanolamine polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium alkane sulfonate, sodium salt of β-naphthalene sulfonic acid formalin condensate, alkoxyalkyl phosphate, alkyl phosphate, diethanolamine alkyl phosphate, sodium alkyl sulfonate special aromatic sulfonic acid formalin condensate, and special carboxylic acid surfactant.

[0118] Examples of amphoteric surfactants include lauryl betaine, stearyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, lauryl dimethylamine oxide, alkyl dimethylamine oxide, and alkyl carboxy betaine.

[0119] Here, the surfactant aqueous solution can be prepared by mixing the above-mentioned surfactant with water by a known method. In this case, the concentration of the surfactant in the surfactant aqueous solution is not particularly limited, and can be, for example, 0.1% by mass or more and 30% by mass or less, and preferably 0.5% by mass or more and 20% by mass or less. The concentration of the surfactant can be from 1% by mass to 10% by mass, and is preferably from 2% by mass to 8% by mass, based on the total solid content contained in the reaction liquid.

[0120] The above polymerization reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen or argon, etc. If necessary, the polymerization may be carried out in the presence of a chain transfer agent (e.g., alkyl mercaptan, etc.).

[0121] The monomer concentration (polymerization concentration) in the reaction system is preferably 20 to 90% by mass, and more preferably 30 to 70% by mass.

[0122] The polymerization temperature is preferably 10°C or higher, more preferably 25°C or higher, and even more preferably 30°C or higher. Also, it is preferably 90°C or lower, more preferably 80°C or lower, and even more preferably 70°C or lower. If the polymerization temperature is 10°C or higher, freezing of the monomer can be prevented, and the reaction efficiency can be increased. Also, if the polymerization temperature is 90°C or lower, the balance between the reaction efficiency and the molecular weight of the obtained polymer can be improved. That is, it is preferable to carry out the polymerization step at a polymerization temperature of 10°C or higher and 90°C or lower.

[0123] The reaction time is usually 1 to 48 hours, preferably 1 to 24 hours, and more preferably 1 to 12 hours.

[0124] In a preferred embodiment, the polymer obtained by the method for producing a polymer of the present invention is a polymer obtained by the above-mentioned polymerization step. If necessary, the polymer may be subjected to a further reaction, such as a decomposition reaction or a substitution reaction, in the presence of an acid or a base, to thereby effect structural transformation. When at least one selected from the group consisting of the above-mentioned monomer (a) and monomer (b) has a group in which a hydroxy group is protected with an acyl group (acyloxy group), the method for producing a polymer of the present invention may further include a deprotection step described below, depending on the desired polymer.

[0125] [Deprotection process] In the method for producing the polymer of the present invention, when polymerization is carried out using the monomer (a) and the monomer (b) in the above polymerization step, a deprotection step of decomposing the acyloxy group may be provided after the polymerization step depending on the desired polymer. In the deprotection step, the acyloxy groups in the polymer obtained in the above polymerization step are decomposed by the action of a base, thereby converting them to -OH groups (hydroxy groups).

[0126] An acyloxy group is a group that decomposes when acted upon by a base. Examples of the base include triethylamine, diisopropylethylamine, diazabicycloundecene, etc. The amount of the base added in the deprotection step is preferably 10 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the polymer. The polymer refers to a polymer obtained in a polymerization process.

[0127] The acyloxy group may be present in the monomer (a) represented by the general formula (I) or may be present in the monomer (b), where the acyloxy group is as described above.

[0128] In a preferred embodiment, a monomer represented by the general formula (II-a) is used as the monomer (b) in the polymerization step, and after the polymerization step, -OR contained in the repeating unit derived from the monomer represented by the general formula (II-a) is 4 It is preferable to further include a deprotection step of converting the group into an --OH group by decomposing it with the action of a base.

[0129] The deprotection reaction can be carried out by heating and mixing the polymer recovered in the polymerization step, a solvent such as cyclohexanone or methanol, and a solution containing the basic compound. The reaction temperature is usually 0°C to 100°C, and may be 20°C to 80°C. The reaction time is usually 12 to 48 hours, and may be 16 to 24 hours.

[0130] In the method for producing the polymer of the present invention, a purification step may be provided after the polymerization step or after the deprotection step. The purification method in the purification step is not particularly limited, and known purification methods such as reprecipitation and column chromatography may be used. The purification of the polymer may be repeated several times.

[0131] [Polymer (A)] The polymer (hereinafter, also referred to as polymer (A) or resin (A)) obtained by the method for producing a polymer of the present invention will be described below.

[0132] One of the preferred aspects of the polymer (A) is a polymer for an actinic ray-sensitive or radiation-sensitive resin composition. From the viewpoint of usefulness as a polymer contained in an actinic ray-sensitive or radiation-sensitive resin composition, the polymer (A) is preferably a so-called main chain decomposition type polymer in which the main chain is decomposed (the main chain is cut) by exposure. When the polymer (A) is a main chain decomposition type polymer, the main chain decomposition may occur due to the structure of the repeating unit derived from the monomer (a), or may occur due to the structure of the repeating unit derived from the monomer (b), but it is preferable that the main chain decomposition occurs due to the structure of the repeating unit derived from the monomer (a).

[0133] The polymer (A) has a repeating unit derived from the monomer (a) represented by the above general formula (I). For the explanation of the monomer (a), the explanation of the monomer (a) in the above-mentioned polymerization steps can be directly applied. In the polymer (A), the content of the repeating units derived from the monomer (a) represented by the general formula (I) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 40 mol% or more, based on the total repeating units. The upper limit is, for example, preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 80 mol% or less, and particularly preferably 60 mol% or less, based on the total repeating units. In the polymer (A), the repeating unit derived from the monomer (a) represented by the general formula (I) may be one type alone or two or more types. When two or more types are contained, the total content is preferably within the above-mentioned suitable content range.

[0134] The polymer (A) has a repeating unit derived from a monomer (b) different from the monomer (a). For the explanation of the monomer (b), the explanation of the monomer (b) in the above-mentioned polymerization steps can be directly applied. As described above, the polymer (A) may or may not be one in which main chain decomposition occurs due to the structure of the repeating unit derived from the monomer (b).

[0135] In a preferred embodiment, the repeating unit derived from the monomer (b) is a repeating unit derived from a monomer represented by the above general formula (II).

[0136] In the polymer (A), the content of the repeating units derived from the monomer represented by the above general formula (II) as the monomer (b) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 40 mol% or more, based on the total repeating units. The upper limit is preferably 90 mol% or less, more preferably 80 mol% or less, even more preferably 70 mol% or less, and particularly preferably 60 mol% or less, based on the total repeating units. In the polymer (A), the repeating unit derived from the monomer (b) may be one type alone or two or more types may be contained. When two or more types are contained, it is preferable that the total content is within the above-mentioned suitable content range.

[0137] The polymer (A) is preferably a copolymer containing a repeating unit derived from the monomer (a) represented by the above general formula (I) and a repeating unit derived from the monomer (monomer (b)) represented by the above general formula (II), and more preferably a copolymer containing a repeating unit derived from the monomer (monomer (a)) represented by the above general formula (I-1) and a repeating unit derived from the monomer (monomer (b)) represented by the above general formula (II). The polymer (A) may be a random copolymer, a block copolymer, or an alternating copolymer, and is more preferably an alternating copolymer.

[0138] In the polymer (A), the total content of the repeating units derived from the monomer represented by the general formula (I) and the repeating units derived from the monomer represented by the general formula (II) (monomer (b)) is preferably 90 mol % or more, more preferably 95 mol % or more, based on the total repeating units. The upper limit is preferably 100 mol % or less.

[0139] The weight average molecular weight (Mw) of the polymer (A) is preferably 5000 or more, more preferably 10000 or more, and even more preferably 20000 or more. When the Mw of the polymer (A) is 5000 or more, the polymer in the unexposed area becomes less soluble, and a dissolution contrast between the unexposed area and the exposed area is easily achieved, which is preferable. Furthermore, the Mw of the polymer (A) is preferably 1,000,000 or less, more preferably 200,000 or less, even more preferably 100,000 or less, and particularly preferably 80,000 or less. When the Mw of the polymer (A) is 1,000,000 or less, the exposed area is easily dissolved, and a dissolution contrast between the unexposed area and the exposed area is easily achieved, which is preferable. That is, the weight average molecular weight of the polymer (A) is preferably 5,000 or more and 1,000,000 or less. The weight average molecular weight is determined by GPC in terms of polystyrene.

[0140] The polymer (A) preferably has a single peak in the molecular weight distribution curve measured by the GPC method. The dispersity (molecular weight distribution) is usually 1.0 to 3.0, preferably 1.0 to 2.0, more preferably 1.0 to 1.9, and even more preferably 1.0 to 1.8. When the dispersity is within the above range, the resolution and resist shape are more likely to be excellent.

[0141] As described above, one of the preferred embodiments of the polymer (A) is a polymer for an actinic ray-sensitive or radiation-sensitive resin composition, and the polymer (A) can be suitably used in an actinic ray-sensitive or radiation-sensitive resin composition.

[0142] The present invention also relates to an actinic ray- or radiation-sensitive resin composition. The actinic ray-sensitive or radiation-sensitive resin composition (hereinafter also referred to as "the composition of the present invention" or "composition A") will be described below. Various components contained in the actinic ray-sensitive or radiation-sensitive resin composition will now be described.

[0143] 〔resin〕 The actinic ray-sensitive or radiation-sensitive resin composition contains, as a resin, a polymer (A) (also referred to as "resin (A)" or "resin") produced by the above-mentioned production method. The polymer (A) is preferably a resin whose main chain decomposes upon exposure to light (hereinafter also referred to as "specific resin"). The resin is preferably a resin whose main chain is decomposed by irradiation with X-rays, an electron beam (EB) or extreme ultraviolet light (EUV light), more preferably a resin whose main chain is decomposed by irradiation with an electron beam or extreme ultraviolet light, and even more preferably a resin whose main chain is decomposed by irradiation with extreme ultraviolet light. The exposure light source is not particularly limited, but examples thereof include the bright line spectrum of a mercury lamp, far ultraviolet light represented by an excimer laser, extreme ultraviolet light, X-rays, and electron beams (EB). Among these, X-rays, electron beams, or EUV light are preferred, electron beams or EUV light are more preferred, and EUV light is even more preferred.

[0144] The resin preferably comprises a copolymer containing a repeating unit derived from the monomer (a) represented by the general formula (I) above and a repeating unit derived from the monomer (monomer (b)) represented by the general formula (II) above, and more preferably a copolymer containing a repeating unit derived from the monomer (monomer (a)) represented by the general formula (I-1) above and a repeating unit derived from the monomer (monomer (b)) represented by the general formula (II) above.

[0145] In the actinic ray- or radiation-sensitive resin composition of the present invention, the content of the resin (preferably the specific resin) is preferably 50.0% by mass or more, more preferably 60.0% by mass or more, and even more preferably 70.0% by mass or more, based on the total solid content of the composition. The upper limit is 100% by mass or less, and preferably 99.9% by mass or less. The resins may be used alone or in combination. When two or more resins are used, the total content is preferably within the above-mentioned suitable content range.

[0146] <Ionic compounds> The actinic ray-sensitive or radiation-sensitive resin composition preferably contains an ionic compound. The ionic compound is more preferably a compound having an onium salt structure that generates an acid upon exposure to light (photodecomposable onium salt compound). When the actinic ray-sensitive or radiation-sensitive resin composition contains an ionic compound such as a photodegradable onium salt compound, the resin whose main chain is decomposed by exposure is likely to aggregate with the ionic compound through an interactive group that may be contained in the resin in the unexposed portion. On the other hand, when exposed to light, the ionic compound dissociates from the interactive group or the photodegradable onium salt compound is cleaved, which may release the aggregated structure. In other words, the dissolution contrast between the unexposed and exposed portions of the actinic ray-sensitive or radiation-sensitive film is further increased by the above action, and the effect of the present invention is more likely to be excellent. In addition, when the actinic ray-sensitive or radiation-sensitive resin composition contains an ionic compound such as a photodecomposable onium salt compound, the resin contained in the actinic ray-sensitive or radiation-sensitive resin composition, the main chain of which is decomposed by exposure, preferably has an interactive group. Examples of the interactive group include the above-mentioned hydroxy group (alcoholic hydroxy group, phenolic hydroxy group, etc.), carboxyl group, sulfonic acid group, amide group, and sulfonamide group.

[0147] The photodecomposable onium salt compound will now be described. The photodecomposable onium salt compound is preferably a compound that has at least one salt structure moiety composed of an anion moiety and a cation moiety, and that decomposes upon exposure to generate an acid (preferably an organic acid). The above-mentioned salt structure portion of the photodecomposable onium salt compound is preferably composed of an organic cation portion and an organic anion portion having extremely low nucleophilicity, because it is easily decomposable upon exposure to light and has excellent organic acid generation properties. The salt structure moiety may be a part or the whole of the photodegradable onium salt compound. The case where the salt structure moiety is a part of the photodegradable onium salt compound corresponds to, for example, a structure in which two or more salt structure moieties are linked together, such as the photodegradable onium salt PG2 described below. The number of salt structure moieties in the photodecomposable onium salt is not particularly limited, but is preferably 1 to 10, more preferably 1 to 6, and further preferably 1 to 3.

[0148] Examples of the organic acid generated from the photodecomposable onium salt compound by the action of exposure to light include sulfonic acids (aliphatic sulfonic acids, aromatic sulfonic acids, camphorsulfonic acids, etc.), carboxylic acids (aliphatic carboxylic acids, aromatic carboxylic acids, aralkyl carboxylic acids, etc.), carbonylsulfonylimide acids, bis(alkylsulfonyl)imide acids, and tris(alkylsulfonyl)methide acids. The organic acid generated from the photodegradable onium salt compound by the action of exposure may be a polyvalent acid having two or more acid groups. For example, when the photodegradable onium salt compound is the photodegradable onium salt compound PG2 described later, the organic acid generated by decomposition of the photodegradable onium salt compound by exposure is a polyvalent acid having two or more acid groups.

[0149] In the photodecomposable onium salt compound, the cationic moiety constituting the salt structure moiety is preferably an organic cationic moiety, and among these, an organic cation represented by formula (ZaI) (cation (ZaI)) or an organic cation represented by formula (ZaII) (cation (ZaII)) described later is preferred. The ionic compound is preferably at least one selected from sulfonium salts and iodonium salts.

[0150] (Photodecomposable onium salt compound PG1) An example of a suitable embodiment of the photodecomposable onium salt compound is "M + X - and a compound which generates an organic acid upon exposure to light (hereinafter also referred to as "photodecomposable onium salt compound PG1"). "M + X - In the compound represented by the formula "M + represents an organic cation, and X - represents an organic anion. The photodecomposable onium salt compound PG1 will be described below.

[0151] M in the photodegradable onium salt compound PG1 + The organic cation represented by the formula (ZaI) (cation (ZaI)), an organic cation represented by the formula (ZaII) (cation (ZaII)), or an ammonium cation is preferred.

[0152] [ka]

[0153] In the above formula (ZaI), R 201 , R 202 , and R 203 each independently represents an organic group. R 201 , R 202 , and R 203 The carbon number of the organic group represented by R is usually 1 to 30, and preferably 1 to 20. 201 ~R 203 Two of these may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester group, an amide group, or a carbonyl group. 201 ~R 203Examples of groups formed by combining two of these include alkylene groups (such as butylene and pentylene groups) and -CH2-CH2-O-CH2-CH2-.

[0154] Suitable embodiments of the organic cation in formula (ZaI) include the cation (ZaI-1), cation (ZaI-2), an organic cation represented by formula (ZaI-3b) (cation (ZaI-3b)), and an organic cation represented by formula (ZaI-4b) (cation (ZaI-4b)), which will be described later.

[0155] First, the cation (ZaI-1) will be described. The cation (ZaI-1) is R 201 ~R 203 is an arylsulfonium cation, in which at least one of the groups is an aryl group. The arylsulfonium cation is R 201 ~R 203 may all be aryl groups, or R 201 ~R 203 A part of the group may be an aryl group, and the remainder may be an alkyl group or a cycloalkyl group. Also, R 201 ~R 203 is an aryl group, and R 201 ~R 203 The remaining two of R may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester group, an amide group, or a carbonyl group. 201 ~R 203 Examples of groups formed by combining two of these groups include alkylene groups in which one or more methylene groups may be substituted with oxygen atoms, sulfur atoms, ester groups, amide groups, and / or carbonyl groups (e.g., butylene groups, pentylene groups, or -CH2-CH2-O-CH2-CH2-). Examples of arylsulfonium cations include triarylsulfonium cations, diarylalkylsulfonium cations, aryldialkylsulfonium cations, diarylcycloalkylsulfonium cations, and aryldicycloalkylsulfonium cations.

[0156] The aryl group contained in the arylsulfonium cation is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure with an oxygen atom, a nitrogen atom, or a sulfur atom. Examples of the heterocyclic structure include a pyrrole residue, a furan residue, a thiophene residue, an indole residue, a benzofuran residue, and a benzothiophene residue. When the arylsulfonium cation has two or more aryl groups, the two or more aryl groups may be the same or different. The alkyl group or cycloalkyl group that the arylsulfonium cation has as necessary is preferably a linear alkyl group having 1 to 15 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, or a cycloalkyl group having 3 to 15 carbon atoms, and more preferably, for example, a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, or a cyclohexyl group.

[0157] R 201 ~R 203 Preferred examples of the substituent that the aryl group, alkyl group, and cycloalkyl group may have are each independently an alkyl group (e.g., having 1 to 15 carbon atoms), a cycloalkyl group (e.g., having 3 to 15 carbon atoms), an aryl group (e.g., having 6 to 14 carbon atoms), an alkoxy group (e.g., having 1 to 15 carbon atoms), a cycloalkylalkoxy group (e.g., having 1 to 15 carbon atoms), a halogen atom (e.g., fluorine, iodine), a hydroxyl group, a carboxyl group, an ester group, a sulfinyl group, a sulfonyl group, an alkylthio group, a phenylthio group, and the like. The above-mentioned substituent may further have a substituent if possible. For example, it is also preferred that the above-mentioned alkyl group has a halogen atom as a substituent to form a halogenated alkyl group such as a trifluoromethyl group.

[0158] Next, the cation (ZaI-2) will be described. The cation (ZaI-2) is R in formula (ZaI). 201 ~R 203 are each independently a cation representing an organic group having no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom. R 201 ~R 203 The organic group having no aromatic ring as the aromatic ring generally has 1 to 30 carbon atoms, and preferably has 1 to 20 carbon atoms. R 201 ~R 203 are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or an alkoxycarbonylmethyl group, and further preferably a linear or branched 2-oxoalkyl group.

[0159] R 201 ~R 203 Examples of the alkyl group and cycloalkyl group include linear alkyl groups having 1 to 10 carbon atoms or branched alkyl groups having 3 to 10 carbon atoms (e.g., methyl, ethyl, propyl, butyl, and pentyl groups), and cycloalkyl groups having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, and norbornyl groups). R 201 ~R 203 may be further substituted with a halogen atom, an alkoxy group (eg, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

[0160] Next, the cation (ZaI-3b) will be described. The cation (ZaI-3b) is a cation represented by the following formula (ZaI-3b).

[0161] [ka]

[0162] In the formula (ZaI-3b), R 1c ~R 5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitro group, an alkylthio group, or an arylthio group. R 6c and R 7c each independently represents a hydrogen atom, an alkyl group (such as a t-butyl group), a cycloalkyl group, a halogen atom, a cyano group, or an aryl group. R x and R y each independently represents an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group, or a vinyl group.

[0163] R 1c ~R 5c Any two or more of the following, R 5c and R 6c , R 6c and R 7c , R 5c and R x , and R x and R y may be bonded to each other to form a ring, and each of these rings may independently contain an oxygen atom, a sulfur atom, a ketone group, an ester bond, or an amide bond. Examples of the ring include aromatic or non-aromatic hydrocarbon rings, aromatic or non-aromatic heterocycles, and polycyclic condensed rings formed by combining two or more of these rings. Examples of the ring include 3- to 10-membered rings, preferably 4- to 8-membered rings, and more preferably 5- or 6-membered rings.

[0164] R 1c ~R 5c Any two or more of the following, R6c and R 7c , and R x and R y Examples of the group formed by bonding include alkylene groups such as butylene and pentylene, in which the methylene group may be substituted with a heteroatom such as an oxygen atom. R 5c and R 6c , and R 5c and R x The group formed by bonding is preferably a single bond or an alkylene group. Examples of the alkylene group include a methylene group and an ethylene group.

[0165] R 1c ~R 5c , R 6c , R 7c , R x , R y , and R 1c ~R 5c Any two or more of the following, R 5c and R 6c , R 6c and R 7c , R 5c and R x , and R x and R y The ring formed by bonding with each other may have a substituent.

[0166] Next, the cation (ZaI-4b) will be described. The cation (ZaI-4b) is a cation represented by the following formula (ZaI-4b).

[0167] [ka]

[0168] In the formula (ZaI-4b), l represents an integer of 0 to 2. r represents an integer of 0 to 8. R 13 is a hydrogen atom, a halogen atom (e.g., a fluorine atom, an iodine atom, etc.), a hydroxyl group, It represents a group having an alkyl group, a halogenated alkyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, or a cycloalkyl group (which may be a cycloalkyl group itself or a group containing a cycloalkyl group as a part). These groups may have a substituent. R 14 represents a hydroxyl group, a halogen atom (e.g., a fluorine atom, an iodine atom, etc.), an alkyl group, R represents a halogenated alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group, or a group having a cycloalkyl group (which may be a cycloalkyl group itself or a group containing a cycloalkyl group as a part). These groups may have a substituent. 14 When a plurality of these are present, each independently represents the above group such as a hydroxyl group. R 15 Each of R independently represents an alkyl group, a cycloalkyl group, or a naphthyl group. 15 may be bonded to each other to form a ring. 15 When two R are bonded to each other to form a ring, the ring structure may contain a heteroatom such as an oxygen atom or a nitrogen atom. 15 are preferably alkylene groups and bonded to each other to form a ring structure. 15 The ring formed by bonding with each other may have a substituent.

[0169] In formula (ZaI-4b), R 13 , R 14 , and R 15 The alkyl group is preferably linear or branched. The number of carbon atoms in the alkyl group is preferably 1 to 10. The alkyl group is more preferably a methyl group, an ethyl group, an n-butyl group, a t-butyl group, or the like.

[0170] Next, formula (ZaII) will be described. In formula (ZaII), R 204 and R 205each independently represents an aryl group, an alkyl group, or a cycloalkyl group. R 204 and R 205 The aryl group of R is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. 204 and R 205 The aryl group may be an aryl group having a heterocycle containing an oxygen atom, a nitrogen atom, a sulfur atom, etc. Examples of the skeleton of the aryl group having a heterocycle include pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene. R 204 and R 205 The alkyl group and cycloalkyl group are preferably a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 10 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group), or a cycloalkyl group having 3 to 10 carbon atoms (for example, a cyclopentyl group, a cyclohexyl group, or a norbornyl group).

[0171] R 204 and R 205 The aryl group, alkyl group, and cycloalkyl group in R may each independently have a substituent. 204 and R 205 Examples of the substituent that the aryl group, alkyl group, and cycloalkyl group may have include an alkyl group (e.g., having 1 to 15 carbon atoms), a cycloalkyl group (e.g., having 3 to 15 carbon atoms), an aryl group (e.g., having 6 to 15 carbon atoms), an alkoxy group (e.g., having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group.

[0172] The ammonium cation is not particularly limited, but may be, for example, N + (R 301 ) 4 is an example of an ammonium cation. R 301 each independently represents an alkyl group (for example, having a carbon number of 1 to 15). The alkyl group may have a substituent.

[0173] X in the photodegradable onium salt compound PG1 - The organic anion represented by the formula (I) is preferably a non-nucleophilic anion (an anion having an extremely low ability to cause a nucleophilic reaction). Examples of non-nucleophilic anions include sulfonate anions (aliphatic sulfonate anions, aromatic sulfonate anions, camphorsulfonate anions, etc.), carboxylate anions (aliphatic carboxylate anions, aromatic carboxylate anions, aralkyl carboxylate anions, etc.), sulfonylimide anions, bis(alkylsulfonyl)imide anions, and tris(alkylsulfonyl)methide anions.

[0174] The organic anion is preferably, for example, an organic anion represented by the following formula (DA).

[0175] [ka]

[0176] In formula (DA), A 31 - R represents an anionic group. a1 represents a hydrogen atom or a monovalent organic group. a1 represents a single bond or a divalent linking group.

[0177] A 31 - represents an anionic group. 31 - The anionic group represented by the formula (B-1) is not particularly limited, but is preferably a group selected from the group consisting of groups represented by formulas (B-1) to (B-14), and among them, formula (B-1), formula (B-2), formula (B-3), formula (B-4), formula (B-5), formula (B-6), formula (B-10), formula (B-12), formula (B-13), or formula (B-14) is more preferable.

[0178] [ka]

[0179] *-O - Formula (B-14)

[0180] In the formulae (B-1) to (B-14), * represents a bonding position. In formulas (B-1) to (B-5) and (B-12), R X1 each independently represents a monovalent organic group. In formula (B-7) and formula (B-11), R X2 Each of R independently represents a hydrogen atom or a substituent other than a fluorine atom or a perfluoroalkyl group. X2 may be the same or different. In formula (B-8), R XF1 represents a hydrogen atom, a fluorine atom, or a perfluoroalkyl group. XF1 At least one of the two R in formula (B-8) represents a fluorine atom or a perfluoroalkyl group. XF1 may be the same or different. In formula (B-9), R X3 represents a hydrogen atom, a halogen atom, or a monovalent organic group. n1 represents an integer of 0 to 4. When n1 represents an integer of 2 to 4, a plurality of R X3 may be the same or different. In formula (B-10), R XF2 represents a fluorine atom or a perfluoroalkyl group. The bond to the bonding position represented by * in formula (B-14) is preferably a phenylene group which may have a substituent. Examples of the substituent which the phenylene group may have include a halogen atom.

[0181] In formulas (B-1) to (B-5) and (B-12), R X1 each independently represents a monovalent organic group. R X1As R, an alkyl group (which may be linear or branched, and preferably has 1 to 15 carbon atoms), a cycloalkyl group (which may be monocyclic or polycyclic, and preferably has 3 to 20 carbon atoms), or an aryl group (which may be monocyclic or polycyclic, and preferably has 6 to 20 carbon atoms) is preferable. X1 The above group represented by the following formula may have a substituent. In addition, in formula (B-5), R X1 It is also preferable that the atom directly bonded to N- in is neither a carbon atom in -CO- nor a sulfur atom in -SO2-.

[0182] R X1 The cycloalkyl group in may be monocyclic or polycyclic. R X1 Examples of the cycloalkyl group in the above formula include a norbornyl group and an adamantyl group.

[0183] R X1 The substituent that the cycloalkyl group in R may have is not particularly limited, but is preferably an alkyl group (which may be linear or branched, and preferably has 1 to 5 carbon atoms). X1 One or more of the carbon atoms which are ring members of the cycloalkyl group in the formula (I) may be replaced by a carbonyl carbon atom.

[0184] R X1 The alkyl group in the formula (I) preferably has 1 to 10 carbon atoms, and more preferably has 1 to 5 carbon atoms. R X1 The substituent that the alkyl group in the formula (I) may have is not particularly limited, but is preferably, for example, a cycloalkyl group, a fluorine atom, or a cyano group. Examples of the cycloalkyl group as the above-mentioned substituent include R X1 The same cycloalkyl groups as those described above when R is a cycloalkyl group are included. R X1 When the alkyl group in the formula (I) has a fluorine atom as the substituent, the alkyl group may be a perfluoroalkyl group. Also, R X1In the alkyl group, one or more -CH2- may be substituted with a carbonyl group.

[0185] R X1 The aryl group in is preferably a benzene ring group. R X1 The substituent that the aryl group in R may have is not particularly limited, but is preferably an alkyl group, a fluorine atom, or a cyano group. Examples of the alkyl group as the substituent include R X1 In the case where is an alkyl group, the alkyl groups described above can be mentioned similarly.

[0186] In formulas (B-7) and (B-11), R X2 Each of R independently represents a hydrogen atom or a substituent other than a fluorine atom or a perfluoroalkyl group (for example, an alkyl group not containing a fluorine atom and a cycloalkyl group not containing a fluorine atom). X2 may be the same or different.

[0187] In formula (B-8), R XF1 represents a hydrogen atom, a fluorine atom, or a perfluoroalkyl group. XF1 At least one of the two R in formula (B-8) represents a fluorine atom or a perfluoroalkyl group. XF1 may be the same or different. XF1 The perfluoroalkyl group represented by the following formula (1) preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and further preferably 1 to 6 carbon atoms.

[0188] In formula (B-9), R X3 R represents a hydrogen atom, a halogen atom, or a monovalent organic group. X3 Examples of the halogen atom as include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and among these, a fluorine atom is preferable. R X3 The monovalent organic group as R X1 This is the same as the monovalent organic group described above. n1 represents an integer of 0 to 4. n1 is preferably an integer of 0 to 2, and more preferably 0 or 1. When n1 represents an integer of 2 to 4, a plurality of R X3 may be the same or different.

[0189] In formula (B-10), R XF2 represents a fluorine atom or a perfluoroalkyl group. R XF2 The perfluoroalkyl group represented by the following formula (1) preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and further preferably 1 to 6 carbon atoms.

[0190] In formula (DA), R a1 The monovalent organic group is not particularly limited, but generally has 1 to 30 carbon atoms, and preferably has 1 to 20 carbon atoms. R a1 is preferably an alkyl group, a cycloalkyl group, or an aryl group.

[0191] The alkyl group may be linear or branched, and is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and further preferably an alkyl group having 1 to 10 carbon atoms. The cycloalkyl group may be monocyclic or polycyclic, and is preferably a cycloalkyl group having 3 to 20 carbon atoms, more preferably a cycloalkyl group having 3 to 15 carbon atoms, and even more preferably a cycloalkyl group having 3 to 10 carbon atoms. The aryl group may be monocyclic or polycyclic and is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms, and even more preferably an aryl group having 6 to 10 carbon atoms.

[0192] The cycloalkyl group may contain heteroatoms as ring members. The heteroatom is not particularly limited, but examples thereof include a nitrogen atom and an oxygen atom. Additionally, the cycloalkyl group may contain a carbonyl bond (>C=O) as a ring member atom. The alkyl group, cycloalkyl group and aryl group may further have a substituent. Also, A31- and R a1 may be bonded to each other to form a ring.

[0193] L a1 The divalent linking group as is not particularly limited, and represents an alkylene group, a cycloalkylene group, an aromatic group, -O-, -CO-, -COO-, or a group formed by combining two or more of these. The alkylene group may be linear or branched and preferably has 1 to 20 carbon atoms, and more preferably has 1 to 10 carbon atoms. The cycloalkylene group may be monocyclic or polycyclic and preferably has 3 to 20 carbon atoms, and more preferably has 3 to 10 carbon atoms. The aromatic group is a divalent aromatic group, preferably an aromatic group having 6 to 20 carbon atoms, and more preferably an aromatic group having 6 to 15 carbon atoms. The aromatic ring constituting the aromatic group is not particularly limited, and examples thereof include aromatic rings having 6 to 20 carbon atoms, specifically, benzene ring, naphthalene ring, anthracene ring, thiophene ring, etc. As the aromatic ring constituting the aromatic group, a benzene ring or a naphthalene ring is preferable, and a benzene ring is more preferable. The alkylene group, cycloalkylene group and aromatic group may further have a substituent, and the substituent is preferably a halogen atom. L a1 Preferably, represents a single bond.

[0194] As the photodecomposable onium salt compound PG1, it is also preferable to use, for example, the photoacid generators disclosed in paragraphs

[0135] to

[0171] of WO 2018 / 193954, paragraphs

[0077] to

[0116] of WO 2020 / 066824, and paragraphs

[0018] to

[0075] and

[0334] to

[0335] of WO 2017 / 154345.

[0195] The molecular weight of the photodegradable onium salt compound PG1 is preferably 3,000 or less, more preferably 2,000 or less, and even more preferably 1,000 or less.

[0196] (Photodecomposition type onium salt compound PG2) Another example of a suitable embodiment of the photodecomposable onium salt compound includes the following compound (I) and compound (II) (hereinafter, "compound (I) and compound (II)" are also referred to as "photodecomposable onium salt compound PG2"). The photodecomposable onium salt compound PG2 has two or more of the above-mentioned salt structure moieties and generates a polyvalent organic acid upon exposure to light. The photodecomposable onium salt compound PG2 will now be described.

[0197] <<Compound (I)>> Compound (I) is a compound having one or more structural moieties X and one or more structural moieties Y, which generates an acid containing a first acidic moiety derived from the structural moiety X and a second acidic moiety derived from the structural moiety Y when irradiated with actinic rays or radiation. Structural part X: Anion part A1 - and cationic moiety M1 + and a structural portion that forms a first acidic site represented by HA1 upon irradiation with actinic rays or radiation. Structural site Y: Anionic site A2 - and cationic moiety M2 + and a structural portion that forms a second acidic site represented by HA2 upon exposure to actinic rays or radiation. However, compound (I) satisfies the following condition I.

[0198] Condition I: In the compound (I), the cationic moiety M1 in the structural moiety X + and the cationic moiety M2 in the structural moiety Y. + H + The compound PI, which is replaced by the cationic moiety M1 in the structural moiety X, + H + The acid dissociation constant a1 derived from the acidic moiety represented by HA1, which is replaced by the cationic moiety M2 in the structural moiety Y + H +and the acid dissociation constant a2 is greater than the acid dissociation constant a1. The compound PI corresponds to an acid generated when compound (I) is irradiated with actinic rays or radiation.

[0199] When compound (I) has two or more structural moieties X, the structural moieties X may be the same or different. - , and two or more of the above M1 + may be the same or different. In addition, in the compound (I), the above A1 - and A2 above - , and the above M1 + and M2 above + may be the same or different, but the above A1 - and A2 above - are preferably different from each other.

[0200] Anion site A1 - and anion site A2 - is a structural moiety containing a negatively charged atom or atomic group, and examples thereof include structural moieties selected from the group consisting of the following formulae (AA-1) to (AA-3) and (BB-1) to (BB-6). In the following formulae (AA-1) to (AA-3) and (BB-1) to (BB-6), * represents a bonding position. In addition, R A R represents a monovalent organic group. A Examples of the monovalent organic group represented by the formula (I) include a cyano group, a trifluoromethyl group, and a methanesulfonyl group.

[0201] [ka]

[0202] In addition, the cationic moiety M1 + and cationic moiety M2 +is a structural moiety containing a positively charged atom or atomic group, and examples thereof include an organic cation having a monovalent charge. The organic cation is not particularly limited, but is preferably an organic cation represented by the above formula (ZaI) (cation (ZaI)) or an organic cation represented by the above formula (ZaII) (cation (ZaII)).

[0203] <<Compound (II)>> Compound (II) is a compound having two or more of the above structural moieties X and one or more of the below-mentioned structural moieties Z, and is a compound that generates an acid containing two or more of the first acidic moieties derived from the structural moiety X and the structural moiety Z when irradiated with actinic rays or radiation. Structural site Z: A non-ionic site capable of neutralizing an acid

[0204] The compound (II) is irradiated with actinic rays or radiation to convert the cationic moiety M1 in the structural moiety X into a cation moiety M2. + H + In other words, the compound PII represents a compound having an acidic site represented by HA1 and a structural site Z which is a nonionic site capable of neutralizing the acid. In addition, in compound (II), the definition of the structural portion X and A1 - and M1 + The definition of the structural moiety X in the compound (I) and A1 - and M1 + The definition and preferred embodiments are also the same as those of the above. The two or more structural moieties X may be the same or different. - , and two or more of the above M1 + may be the same or different.

[0205] The nonionic moiety capable of neutralizing an acid in the structural moiety Z is not particularly limited, and is preferably, for example, a moiety containing a functional group having an electron or a group capable of electrostatically interacting with a proton. Examples of functional groups having a group or electrons capable of electrostatically interacting with a proton include functional groups having a macrocyclic structure such as cyclic polyether, or functional groups having a nitrogen atom having an unshared electron pair that does not contribute to π conjugation. The nitrogen atom having an unshared electron pair that does not contribute to π conjugation is, for example, a nitrogen atom having a partial structure shown in the following formula:

[0206] [ka]

[0207] Examples of the partial structure of the functional group having a group or electron capable of electrostatically interacting with a proton include a crown ether structure, an azacrown ether structure, a primary to tertiary amine structure, a pyridine structure, an imidazole structure, and a pyrazine structure. Among these, a primary to tertiary amine structure is preferable.

[0208] The molecular weight of the photodegradable onium salt compound PG2 is preferably 100 to 10,000, more preferably 100 to 2,500, and even more preferably 100 to 1,500.

[0209] As the photodecomposable onium salt compound PG2, the compounds exemplified in paragraphs

[0023] to

[0095] of International Publication No. 2020 / 158313 can be cited.

[0210] Examples of moieties other than cations that the photodecomposable onium salt compound PG2 may have are shown below.

[0211] [ka]

[0212] [ka]

[0213] In the actinic ray-sensitive or radiation-sensitive resin composition of the present invention, the content of the ionic compound is not particularly limited, but is preferably 0.1 to 20 mass% based on the total solid content of the actinic ray-sensitive or radiation-sensitive resin composition. The lower limit of the content is more preferably 0.5 mass% or more, even more preferably 1.0 mass% or more, and particularly preferably 2.0 mass% or more. The upper limit of the content is more preferably 15.0 mass% or less, and even more preferably 10.0 mass% or less. The ionic compound may be used alone or in combination of two or more. When two or more types are used, the total content is preferably within the above-mentioned suitable content range.

[0214] 〔solvent〕 The actinic ray-sensitive or radiation-sensitive resin composition of the present invention preferably contains a solvent. The solvent preferably contains (M1) propylene glycol monoalkyl ether carboxylate and (M2) at least one selected from the group consisting of propylene glycol monoalkyl ether, lactate ester, acetate ester, alkoxypropionate ester, linear ketone, cyclic ketone, lactone, and alkylene carbonate. The solvent may further contain components other than the components (M1) and (M2).

[0215] When such a solvent is used in combination with the above-mentioned resin whose main chain decomposes upon exposure, the coatability of the actinic ray-sensitive or radiation-sensitive resin composition is improved and a pattern with fewer development defects is easily formed. This is presumably because these solvents have an excellent balance of the solubility, boiling point, and viscosity of the above-mentioned resin whose main chain decomposes upon exposure, and therefore can suppress unevenness in the film thickness of the actinic ray-sensitive or radiation-sensitive film, which is a composition film of the actinic ray-sensitive or radiation-sensitive resin composition, and the occurrence of precipitates during spin coating.

[0216] The component (M1) is preferably at least one selected from the group consisting of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether propionate, and propylene glycol monoethyl ether acetate, and more preferably propylene glycol monomethyl ether acetate (PGMEA).

[0217] As the component (M2), the following are preferred. As the propylene glycol monoalkyl ether, propylene glycol monomethyl ether (PGME) and propylene glycol monoethyl ether (PGEE) are preferable. The lactate ester is preferably ethyl lactate, butyl lactate, or propyl lactate. The acetate ester is preferably methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, isoamyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, or 3-methoxybutyl acetate. Also preferred is butyl butyrate. As the alkoxypropionate, methyl 3-methoxypropionate (MMP) or ethyl 3-ethoxypropionate (EEP) is preferable. As the chain ketone, 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 2-heptanone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, or methyl amyl ketone is preferred. The cyclic ketone is preferably methylcyclohexanone, isophorone, cyclopentanone, or cyclohexanone. The lactone is preferably γ-butyrolactone. As the alkylene carbonate, propylene carbonate is preferred.

[0218] As the component (M2), propylene glycol monomethyl ether (PGME), ethyl lactate, ethyl 3-ethoxypropionate, methyl amyl ketone, cyclohexanone, butyl acetate, pentyl acetate, γ-butyrolactone, or propylene carbonate is more preferable.

[0219] In addition to the above-mentioned components, the solvent preferably contains an ester-based solvent having 7 or more carbon atoms (preferably 7 to 14, more preferably 7 to 12, and even more preferably 7 to 10) and 2 or less heteroatoms. As the ester-based solvent having 7 or more carbon atoms and 2 or less heteroatoms, amyl acetate, 2-methylbutyl acetate, 1-methylbutyl acetate, hexyl acetate, pentyl propionate, hexyl propionate, butyl propionate, isobutyl isobutyrate, heptyl propionate, or butyl butanoate is preferred, and isoamyl acetate is more preferred.

[0220] As the component (M2), those having a flash point (hereinafter also referred to as fp) of 37°C or more are preferred. As such a component (M2), propylene glycol monomethyl ether (fp: 47°C), ethyl lactate (fp: 53°C), ethyl 3-ethoxypropionate (fp: 49°C), methyl amyl ketone (fp: 42°C), cyclohexanone (fp: 44°C), pentyl acetate (fp: 45°C), methyl 2-hydroxyisobutyrate (fp: 45°C), γ-butyrolactone (fp: 101°C), or propylene carbonate (fp: 132°C) are preferred. Among these, propylene glycol monoethyl ether, ethyl lactate, pentyl acetate, or cyclohexanone are more preferred, and propylene glycol monoethyl ether or ethyl lactate are even more preferred. The "flash point" used herein means the value listed in the reagent catalog of Tokyo Chemical Industry Co., Ltd. or Sigma-Aldrich Co.

[0221] The solvent preferably contains component (M1). More preferably, the solvent consists essentially of component (M1) alone, or is a mixed solvent of component (M1) and other components. In the latter case, the solvent further preferably contains both component (M1) and component (M2). The mass ratio (M1 / M2) of the component (M1) to the component (M2) is preferably in the range of "100 / 0" to "15 / 85", more preferably in the range of "100 / 0" to "40 / 60", and even more preferably in the range of "100 / 0" to "60 / 40". That is, the solvent is preferably composed of only the component (M1) or contains both the component (M1) and the component (M2), and the mass ratio thereof is as follows. That is, in the latter case, the mass ratio of the component (M1) to the component (M2) is preferably 15 / 85 or more, more preferably 40 / 60 or more, and even more preferably 60 / 40 or more. By adopting such a configuration, it is possible to further reduce the number of development defects.

[0222] When the solvent contains both the component (M1) and the component (M2), the mass ratio of the component (M1) to the component (M2) is, for example, 99 / 1 or less.

[0223] When the solvent further contains components other than the components (M1) and (M2), the content of the components other than the components (M1) and (M2) is preferably 5 to 30 mass % based on the total amount of the solvent.

[0224] The content of the solvent in the actinic ray-sensitive or radiation-sensitive resin composition of the present invention is preferably determined so that the solid content concentration is 0.5 to 30 mass%, and more preferably 1 to 20 mass%, in terms of better coatability.

[0225] [Surfactant] The actinic ray-sensitive or radiation-sensitive resin composition of the present invention may contain a surfactant. When the composition contains a surfactant, a pattern having excellent adhesion and fewer development defects can be formed. The surfactant is preferably a fluorine-based and / or silicon-based surfactant. Examples of fluorine-based and / or silicone-based surfactants include the surfactants disclosed in paragraphs

[0218] and

[0219] of WO 2018 / 193954.

[0226] These surfactants may be used alone or in combination of two or more.

[0227] When the actinic ray-sensitive or radiation-sensitive resin composition of the present invention contains a surfactant, the content of the surfactant is preferably from 0.0001 to 2 mass %, more preferably from 0.0005 to 1 mass %, based on the total solid content of the composition.

[0228] The present invention also relates to a method for producing an actinic ray-sensitive or radiation-sensitive resin composition, the method for producing the composition comprising the steps of: A step of producing a polymer by the polymer production method of the present invention; The method includes a step of mixing the polymer (also referred to as "resin") with a solvent, A method for producing an actinic ray-sensitive or radiation-sensitive resin composition.

[0229] The method for producing the polymer of the present invention is as described above.

[0230] The method for producing the composition includes a step of mixing the polymer with a solvent. The mixing step is not particularly limited. The solvent is the same as the solvent in the composition of the present invention described above, and the preferred range is also the same.

[0231] It is preferable that the composition produced by the above-mentioned method for producing a composition further includes at least one ionic compound mixed therein in the above-mentioned mixing step. The ionic compound is the same as the ionic compound in the composition of the present invention described above, and the preferred range is also the same. In a preferred embodiment, the ionic compound is at least one selected from a sulfonium salt and an iodonium salt. When other components are contained in addition to the ionic compound and the solvent, the other components may be mixed in addition to the resin, the ionic compound, and the solvent, or the other components may be added to the mixture after the step of mixing the polymer, the ionic compound, and the solvent.

[0232] [Actinic ray- or radiation-sensitive film, pattern formation method] The present invention also relates to an actinic ray-sensitive or radiation-sensitive film (preferably a resist film) formed using the actinic ray-sensitive or radiation-sensitive resin composition. The present invention also relates to a pattern forming method, comprising the steps of forming an actinic ray-sensitive or radiation-sensitive film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition, exposing the actinic ray-sensitive or radiation-sensitive film, and developing the exposed actinic ray-sensitive or radiation-sensitive film with a developer.

[0233] The procedure for the pattern formation method using the actinic ray-sensitive or radiation-sensitive resin composition is not particularly limited, but it is preferable that the method comprises the following steps. Step 1: A step of forming an actinic ray-sensitive or radiation-sensitive film on a substrate using an actinic ray-sensitive or radiation-sensitive resin composition. Step 2: Exposing the actinic ray- or radiation-sensitive film to light Step 3: A step of developing the exposed actinic ray- or radiation-sensitive film with a developer. The procedures for each of the above steps will be described in detail below.

[0234] <Step 1: Actinic ray-sensitive or radiation-sensitive film formation step> Step 1 is a step of forming an actinic ray-sensitive or radiation-sensitive film on a substrate using an actinic ray-sensitive or radiation-sensitive resin composition.

[0235] Examples of a method for forming an actinic ray-sensitive or radiation-sensitive film on a substrate using the actinic ray-sensitive or radiation-sensitive resin composition include a method of coating the actinic ray-sensitive or radiation-sensitive resin composition on a substrate. In addition, it is preferable to filter the actinic ray-sensitive or radiation-sensitive resin composition as necessary before coating. The pore size of the filter is preferably 0.1 μm or less, more preferably 0.05 μm or less, and even more preferably 0.03 μm or less. In addition, the filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon.

[0236] The actinic ray-sensitive or radiation-sensitive resin composition can be applied onto a substrate (e.g., silicon, silicon coated with silicon dioxide) such as that used in the manufacture of integrated circuit elements by a suitable application method such as a spinner or coater. The application method is preferably spin application using a spinner. The rotation speed when spin application using a spinner is preferably 1000 to 3000 rpm. After coating the actinic ray-sensitive or radiation-sensitive resin composition, the substrate may be dried to form an actinic ray-sensitive or radiation-sensitive film. If necessary, various undercoats (inorganic films, organic films, anti-reflection films) may be formed under the actinic ray-sensitive or radiation-sensitive film.

[0237] An example of a drying method is a method of drying by heating. Heating can be performed by a means provided in a normal exposure machine and / or a developing machine, and may be performed using a hot plate or the like. The heating temperature is preferably 80 to 150° C., more preferably 80 to 140° C., and even more preferably 80 to 130° C. The heating time is preferably 30 to 1000 seconds, more preferably 60 to 800 seconds, and even more preferably 60 to 600 seconds.

[0238] The thickness of the actinic ray-sensitive or radiation-sensitive film is not particularly limited, but is preferably 10 to 120 nm in terms of forming a fine pattern with higher accuracy. In particular, in the case of EUV exposure and EB exposure, the thickness of the actinic ray-sensitive or radiation-sensitive film is more preferably 10 to 65 nm, and even more preferably 15 to 50 nm. In addition, in the case of ArF immersion exposure, the thickness of the resist film is more preferably 10 to 120 nm, and even more preferably 15 to 90 nm.

[0239] A top coat may be formed on the actinic ray-sensitive or radiation-sensitive film by using a top coat composition. It is preferable that the top coat composition does not mix with the actinic ray-sensitive or radiation-sensitive film, and can be uniformly applied on the actinic ray-sensitive or radiation-sensitive film. The top coat is not particularly limited, and a conventionally known top coat can be formed by a conventionally known method, for example, a top coat can be formed based on the description in paragraphs

[0072] to

[0082] of JP2014-059543A. For example, it is preferable to form a top coat containing a basic compound such as that described in JP 2013-061648 A on the actinic ray-sensitive or radiation-sensitive film. Specific examples of the basic compound that the top coat may contain include basic compounds that may be contained in the actinic ray-sensitive or radiation-sensitive resin composition. The top coat also preferably contains a compound containing at least one group or bond selected from the group consisting of an ether bond, a thioether bond, a hydroxyl group, a thiol group, a carbonyl bond, and an ester bond.

[0240] <Step 2: Exposure step> Step 2 is a step of exposing the actinic ray- or radiation-sensitive film to light. The exposure method may be a method in which the formed actinic ray-sensitive or radiation-sensitive film is irradiated with actinic rays or radiation through a predetermined mask. Examples of actinic rays or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-rays, and electron beams, preferably far ultraviolet light having a wavelength of 250 nm or less, more preferably 220 nm or less, and particularly preferably 1 to 200 nm, specifically, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F2 excimer laser (157 nm), EUV (13 nm), X-rays, and electron beams.

[0241] After exposure, it is preferable to carry out a post-exposure heat treatment (also called post-exposure bake) before development, which promotes the reaction of the exposed area and improves the sensitivity and pattern shape. The heating temperature is preferably from 80 to 150°C, more preferably from 80 to 140°C, and even more preferably from 80 to 130°C. The heating time is preferably from 10 to 1000 seconds, more preferably from 10 to 180 seconds, and further preferably from 30 to 120 seconds. Heating can be carried out by a means provided in a normal exposure machine and / or developing machine, and may also be carried out using a hot plate or the like.

[0242] <Process 3: Development process> Step 3 is a step of developing the exposed actinic ray- or radiation-sensitive film with a developer to form a pattern. The developer is preferably a developer containing an organic solvent (hereinafter, also referred to as an organic developer).

[0243] Examples of development methods include a method in which a substrate is immersed in a tank filled with developer for a certain period of time (dip method), a method in which developer is piled up on the substrate surface by surface tension and left stationary for a certain period of time for development (paddle method), a method in which developer is sprayed onto the substrate surface (spray method), and a method in which developer is continuously dispensed while a developer dispensing nozzle is scanned at a constant speed onto a substrate rotating at a constant speed (dynamic dispense method). After the developing step, a step of stopping the development while replacing the solvent with another solvent may be carried out. The development time is not particularly limited as long as the resin in the unexposed area is sufficiently dissolved, and is preferably from 10 to 300 seconds, more preferably from 20 to 120 seconds. The temperature of the developer is preferably from 0 to 50°C, and more preferably from 15 to 35°C.

[0244] The organic developer is preferably a developer containing at least one organic solvent selected from the group consisting of ketone-based solvents, ester-based solvents, alcohol-based solvents, amide-based solvents, ether-based solvents, and hydrocarbon-based solvents.

[0245] The above solvents may be mixed in combination, or may be mixed with a solvent other than the above or with water. The water content of the developer as a whole is preferably less than 50% by mass, more preferably less than 20% by mass, even more preferably less than 10% by mass, and particularly preferably substantially free of water. The content of the organic solvent in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, still more preferably 90% by mass or more and 100% by mass or less, and particularly preferably 95% by mass or more and 100% by mass or less, based on the total amount of the developer.

[0246] <Other processes> The above pattern formation method preferably includes, after step 3, a step of washing with a rinsing liquid.

[0247] The rinse liquid used in the rinse step after the development step using an organic developer is not particularly limited as long as it does not dissolve the pattern, and a solution containing a general organic solvent can be used. The rinse liquid is preferably a rinse liquid containing at least one organic solvent selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents.

[0248] The method of the rinsing step is not particularly limited, and examples thereof include a method of continuously discharging a rinsing liquid onto a substrate rotating at a constant speed (spin coating method), a method of immersing a substrate in a tank filled with the rinsing liquid for a certain period of time (dip method), and a method of spraying the rinsing liquid onto the substrate surface (spray method). The pattern forming method of the present invention may also include a heating step (Post Bake) after the rinsing step. This step removes the developer and rinsing solution remaining between and inside the patterns due to baking. This step also has the effect of annealing the resist pattern and improving the surface roughness of the pattern. The heating step after the rinsing step is usually performed at 40 to 250°C (preferably 90 to 200°C) for usually 10 seconds to 3 minutes (preferably 30 seconds to 120 seconds).

[0249] Furthermore, the substrate may be etched using the formed pattern as a mask. That is, the substrate (or the underlayer film and the substrate) may be processed using the pattern formed in step 3 as a mask to form a pattern on the substrate. Although the method for processing the substrate (or the underlayer film and the substrate) is not particularly limited, a method for forming a pattern on the substrate is preferable by performing dry etching on the substrate (or the underlayer film and the substrate) using the pattern formed in step 3 as a mask. The dry etching is preferably oxygen plasma etching.

[0250] The actinic ray- or radiation-sensitive resin composition and various materials used in the pattern forming method of the present invention (e.g., solvent, developer, rinse, anti-reflective film forming composition, top coat forming composition, etc.) preferably do not contain impurities such as metals. The content of impurities contained in these materials is preferably 1 mass ppm or less, more preferably 10 mass ppb or less, even more preferably 100 mass ppt or less, particularly preferably 10 mass ppt or less, and most preferably 1 mass ppt or less. Here, examples of metal impurities include Na, K, Ca, Fe, Cu, Mg, Al, Li, Cr, Ni, Sn, Ag, As, Au, Ba, Cd, Co, Pb, Ti, V, W, and Zn.

[0251] Examples of methods for removing impurities such as metals from various materials include filtration using a filter. Details of filtration using a filter are described in paragraph

[0321] of International Publication No. WO 2020 / 004306.

[0252] Methods for reducing impurities such as metals contained in various materials include, for example, selecting raw materials with a low metal content as the raw materials constituting the various materials, filtering the raw materials constituting the various materials, and performing distillation under conditions that suppress contamination as much as possible, for example by lining the inside of the apparatus with Teflon (registered trademark).

[0253] In addition to the filter filtration, the impurities may be removed by an adsorbent, or the filter filtration and the adsorbent may be used in combination. As the adsorbent, a known adsorbent may be used, for example, an inorganic adsorbent such as silica gel and zeolite, and an organic adsorbent such as activated carbon. In order to reduce impurities such as metals contained in the above various materials, it is necessary to prevent the incorporation of metal impurities in the manufacturing process. Whether or not metal impurities have been sufficiently removed from the manufacturing equipment can be confirmed by measuring the content of metal components contained in the cleaning solution used to clean the manufacturing equipment. The content of metal components contained in the cleaning solution after use is preferably 100 parts per trillion (ppt) by mass or less, more preferably 10 ppt by mass or less, and even more preferably 1 ppt by mass or less.

[0254] The actinic ray-sensitive or radiation-sensitive resin composition may contain water as an impurity. When water is contained as an impurity, the smaller the content of water, the more preferable, but the water may be contained in an amount of 1 to 30,000 ppm by mass based on the entire actinic ray-sensitive or radiation-sensitive resin composition. The actinic ray-sensitive or radiation-sensitive resin composition may also contain residual monomers as impurities (for example, monomers derived from raw material monomers used in the synthesis of a specific resin). When the residual monomers are contained as impurities, the smaller the content of the residual monomers, the more preferable, but the content of the residual monomers may be 1 to 30,000 ppm by mass relative to the total solid content of the resist composition.

[0255] A conductive compound may be added to an organic processing liquid such as a rinse liquid in order to prevent breakdown of chemical piping and various parts (filters, O-rings, tubes, etc.) due to static electricity buildup and subsequent static electricity discharge. The conductive compound is not particularly limited, but an example thereof is methanol. The amount added is not particularly limited, but in terms of maintaining favorable development characteristics or rinsing characteristics, it is preferably 10% by mass or less, more preferably 5% by mass or less. For example, SUS (stainless steel), or various pipes coated with antistatic polyethylene, polypropylene, or fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.) can be used as the chemical liquid pipe. Similarly, for the filter and O-ring, antistatic polyethylene, polypropylene, or fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.) can be used.

[0256] [Electronic device manufacturing method] The present invention also relates to a method for manufacturing an electronic device, which includes the above-mentioned pattern formation method, and an electronic device manufactured by this manufacturing method. The electronic device of the present invention is suitably mounted in electric and electronic equipment (such as home appliances, OA (Office Automation), media-related equipment, optical equipment, and communication equipment). EXAMPLES

[0257] The present invention will be described in more detail below based on examples. The materials, amounts, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following examples.

[0258] <Synthesis Example 1: Synthesis of Resin A-2>

[0259] [ka]

[0260] <Preparation of Monomer> Under a nitrogen stream, 100 g of acetic anhydride and monomer Mb-2 (30 g) were placed in a three-neck flask and heated to 120°C. After one hour, the reaction was stopped and the acetic anhydride was removed using an evaporator. 100 g of diisopropyl ether was added thereto and stirred at room temperature for one hour. The resulting powder was filtered to obtain monomer Mb-2a (25.8 g). In the above structural formula, Ac represents an acetyl group.

[0261] Monomer Ma-2 (50 g) and TEMPO (1 g) were placed in a three-neck flask under a nitrogen stream, and vacuum distillation was carried out at 30 torr / 85° C. Note that 1 torr = approximately 133.322 Pa. To 30 g of the obtained liquid, 990 mg of MEHQ (methoxyhydroquinone) was added to prepare monomer Ma-2 having an MEHQ concentration of 3,300 ppm by mass relative to monomer Ma-2.

[0262] <Polymerization process> Under a nitrogen stream, 5.33 g of cyclohexanone was placed in a three-neck flask and heated to 80 ° C. Then, in the three-neck flask, 11.54 g of monomer Ma-2, 8.73 g of monomer Mb-2a, 0.58 g of a 20 mass% cyclohexanone solution of polymerization initiator V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and a mixed solution of 21.1 g of cyclohexanone were dropped over 4 hours, and after the dropwise addition, the reaction was allowed to continue for 2 hours at 80 ° C. After the reaction was completed, the reaction liquid was allowed to cool. After adding 60 g of cyclohexanone to the obtained reaction liquid, the mixture was dropped into 700 g of methanol, and the powder precipitated by the dropwise addition was filtered and dried to obtain resin A-2a.

[0263] Next, under a nitrogen stream, 30 g of cyclohexanone, 30 g of methanol, 10 g of triethylamine, and Resin A-2a were placed in a three-neck flask, which was then heated to 80° C., and the reaction was stopped after 24 hours. To the resulting solution, 100 g of ethyl acetate was added, and the solution was separated with 300 ml of 1N hydrochloric acid, 300 ml of 0.1N hydrochloric acid, and 500 ml of water three times. The resulting solution was concentrated in an evaporator, and 40 g of methanol was added to dissolve the product. The obtained solution was added dropwise to 600 ml of water, and the powder precipitated by the addition was collected by filtration and dried to obtain Resin A-2.

[0264] Regarding the above resin A-2, C 13 The composition ratio (molar ratio) of the repeating units determined by the NMR (Nuclear Magnetic Resonance) method was 55 / 45 (repeating units derived from monomer Ma-2 / repeating units derived from monomer Mb-2). The weight average molecular weight of the obtained resin A-2 measured by GPC was 32000 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.67. The monomer Mb-2 is as described below.

[0265] <Synthesis Example 2: Synthesis of Resin A-1> Under a nitrogen stream, 5.33 g of cyclohexanone was placed in a three-neck flask and heated to 80°C. Next, a mixed solution of 14.85 g of α-methylstyrene, 15.15 g of α-methyl acrylate, 0.87 g of a 10% by mass solution of polymerization initiator V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 1.4 g of cyclohexanone was dropped into the three-neck flask over 4 hours, and after the dropwise addition, the mixture was further reacted at 80°C for 2 hours. After the reaction, the reaction liquid was allowed to cool. After adding 60 g of cyclohexanone to the obtained reaction liquid, the mixture was dropped into 700 g of methanol, and the powder precipitated by the dropwise addition was filtered and dried to obtain resin A-1.

[0266] <Synthesis Example 3: Synthesis of Resin A-24> Under a nitrogen stream, 10 g of water was placed in a three-neck flask and heated to 80° C. Next, a mixed solution containing 15.15 g of methyl α-chloroacrylate, 14.85 g of α-methylstyrene, 6.7 g of an aqueous solution of semi-hardened beef tallow fatty acid potassium soap with a solid content of 18% as an aqueous surfactant solution, 1.2 g of potassium persulfate, and 13.3 g of ion-exchanged water was added dropwise over 4 hours, and after the dropwise addition was completed, the mixture was allowed to react at 80° C. for a further 24 hours. Then, 10 g of tetrahydrofuran as a good solvent was added to the obtained polymer solution, and the polymer solution to which the good solvent was added was dropped into 400 g of methanol as a poor solvent to precipitate a copolymer. The precipitated powder was then filtered and dried to obtain Resin A-24.

[0267] [Various components of actinic ray- or radiation-sensitive resin composition] [Resin (A)] The resins shown in Table 2 (A-1 to A-31 and H-1 to H-3) are shown below. A-2 was synthesized by the above-mentioned synthesis method (Synthesis Example 1). A-2 to A-21, A-23, A-27, A-28, and A-29 were synthesized according to Synthesis Example 1 under the polymerization conditions shown in Table 1. A-1 was synthesized by the above-mentioned synthesis method (Synthesis Example 2). A-22, A-25, A-26, A-30, and A-31 were synthesized according to Synthesis Example 2 under the polymerization conditions shown in Table 1. A-24 was used which was synthesized by the above-mentioned synthesis method (Synthesis Example 3). H-1 was synthesized in the same manner as in the above-mentioned synthesis method (Synthesis Example 2) except that MEHQ was not added. H-2 to H-3 were synthesized in the same manner as in the above-mentioned synthesis method (Synthesis Example 2) except that the amount of MEHQ was changed to the value shown in Table 1 and were used.

[0268] Table 1 shows the polymerization conditions, products, and compositions (types of monomers (a) and (b), composition ratios of repeating units (mol % ratios, corresponding to repeating units derived from monomer (a) and repeating units derived from monomer (b) from the left), weight average molecular weights (Mw), and polydispersity (PDI: Mw / Mn)) of resins A-1 to A-31 and H-1 to H-3. The weight average molecular weight (Mw) and dispersity (Mw / Mn) of resins A-1 to A-31, as well as the Mw of resins H-1 to H-3 and the dispersity (Mw / Mn) of resin H-2 were measured by GPC (carrier: tetrahydrofuran (THF)) (polystyrene equivalent). The composition ratios (mol %) of the resins are as follows: 13 Measurements were performed using C-NMR (Nuclear Magnetic Resonance).

[0269] The repeating units derived from the monomer (a) in each of the resulting resins (products) are shown in Table 1 as "monomer (a)". The repeating units derived from the monomer (b) in each of the obtained resins (products) are shown in Table 1 as "monomer (b)".

[0270] In Table 1, the following were used as polymerization solvents. Cp: ​​Cyclopentanone PGMEA: Propylene glycol monomethyl ether acetate PGME: Propylene glycol monomethyl ether XAN: Cyclohexanone

[0271] As the polymerization inhibitors shown in Table 1, TEMPO, MEHQ, HQ, BHT, and BQ are as described above. The amount of the polymerization inhibitor (B) added is the amount added relative to the monomer (a). The amount of surfactant added in Table 1 is the amount added relative to the total solid content contained in the reaction liquid.

[0272] [Table 1]

[0273] [Table 2]

[0274] [Table 3]

[0275] [Table 4]

[0276] The monomers (a) and (b) in Table 1 above are as follows: Me represents a methyl group, and Ac represents an acetyl group.

[0277] [ka]

[0278] [ka]

[0279] [ka] TIFF2025043125000029.tif39166

[0280] [ka]

[0281] [Ionic Compounds] The structures of the ionic compounds (C-1 to C-10) shown in Table 2 are shown below. All of the onium salt compounds (C-1 to C-10) are photodecomposable onium salt compounds.

[0282] [ka]

[0283] 〔solvent〕 The solvents shown in Table 2 are as follows: D-1: Propylene glycol monomethyl ether acetate (PGMEA) D-2: Propylene glycol monomethyl ether (PGME) D-3: Cyclohexanone D-4: Ethyl lactate D-5: γ-butyrolactone D-6: Diacetone alcohol

[0284] [Preparation of resist composition] The components other than the solvent shown in Table 2 were mixed so that the solid content concentration was 1.3 mass %. The resulting mixture was then filtered through a polyethylene filter having a pore size of 0.03 μm to prepare resist compositions (Re-1 to Re-31, and CRe-1 to CRe-3). Here, the solid content refers to all components other than the solvent. The resulting resist compositions were used in the examples and comparative examples. The contents (mass %) of the resin and ionic compound in Table 2 indicate the contents in the total solid content of the composition.

[0285]

Table 5

[0286] [Pattern Formation Method (1): EUV Exposure, Organic Solvent Development] The resist composition was applied onto a silicon wafer and then baked at 120 °C for 60 seconds to form a resist film. The film thickness of the resist film at this time was adjusted to 40 nm. Pattern irradiation was performed on the silicon wafer having the resist film obtained by the above procedure using an EUV exposure apparatus (manufactured by Exitech, Micro Exposure Tool, NA0.3, Quadrupol, Outer Sigma 0.68, Inner Sigma 0.36). Note that as the reticle, a mask with a line:space = 1:1 was used. After baking the exposed resist film at 90 °C for 60 seconds, it was developed with the developer described in Table 3 for 30 seconds. As long as there is a description, the rinse liquid described in Table 3 was poured for 10 seconds while rotating the wafer at a rotation speed of 1000 rpm for rinsing, and this was spin-dried to obtain a line and space pattern (line:space = 1:1) with a pitch of 40 nm.

[0287] [Evaluation] <Resolution> The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope (S-9380II manufactured by Hitachi, Ltd.). The optimum exposure dose when resolving a resist pattern of 1:1 line and space with a line width of 20 nm was defined as the sensitivity (Eopt) (mJ / cm 2 ), and the limit resolution (the minimum line width at which the line and space (line:space = 1:1) are resolved separately) at the exposure dose showing the above sensitivity (Eop) was defined as the resolution (nm). The smaller this value is, the higher the resolution.

[0288] <LWR (line width roughness) Performance> A 20 nm (1:1) line and space pattern resolved at an exposure dose showing the above sensitivity (Eopt) was observed from above using a critical dimension scanning electron microscope (SEM (S-9380II, manufactured by Hitachi, Ltd.)). The line width of the pattern was observed at 100 random points, the standard deviation (σ) was calculated, and the measurement variation of the line width was evaluated at 3σ (nm). The smaller the value, the better the performance.

[0289] The resist compositions used and the results are shown in Table 3 below.

[0290] [Table 6]

[0291] The developing solution and rinsing solution in Table 3 are described below. E-1: Butyl acetate E-2: Isopropyl acetate E-3: Butyl acetate:n-undecane=90:10 (mass ratio) E-4: Cyclopentanone:n-undecane=70:30 (mass ratio)

[0292] [Pattern formation method (2): EB exposure, organic solvent development] The resist composition was applied onto a silicon wafer and then baked at 120° C. for 60 seconds to form a resist film, the thickness of which was adjusted to 40 nm. The silicon wafer having the resist film obtained by the above-mentioned procedure was subjected to pattern irradiation using an electron beam lithography system (Advantest Corporation; F7000S, acceleration voltage 50 keV). At this time, lithography was performed so as to form a 1:1 line and space. After electron beam writing, the resist film was baked at 90°C for 60 seconds, and then developed for 30 seconds with the developer shown in Table 4. Only when otherwise specified, the wafer was rinsed by pouring the rinse solution shown in Table 4 over it for 10 seconds while rotating the wafer at 1000 rpm, and then spin-dried to obtain a line and space pattern with a pitch of 40 nm (line:space = 1:1).

[0293] [Evaluation] [Resolution] The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope (S-9380II manufactured by Hitachi, Ltd.). The optimum exposure dose when resolving a resist pattern of 1:1 line and space with a line width of 20 nm was defined as the sensitivity (Eopt) (μC / cm 2 ), and the limit resolution (the minimum line width at which the line and space (line:space = 1:1) are resolved separately) at the exposure dose showing the above sensitivity (Eop) was defined as the resolution (nm). The smaller this value, the higher the resolution.

[0294] [LWR (line width roughness) performance] For a 20 nm (1:1) line and space pattern resolved at the exposure dose showing the above sensitivity (Eopt), observation was made from the top of the pattern using a length-measuring scanning electron microscope (SEM (S-9380II manufactured by Hitachi, Ltd.)). The line width of the pattern was observed at 100 arbitrary points, the standard deviation (σ) was determined, and the measurement variation of the line width was evaluated by 3σ (nm). A smaller value indicates better performance.

[0295] The resist compositions used and the results are shown in Table 4 below.

[0296]

Table 7

[0297] According to Table 1, it can be seen that according to the method for producing the resin of the present invention, a desired polymer can be produced with high purity and high efficiency. Also, from the results shown in Table 3 and Table 4, it can be seen that according to the photoactive ray-sensitive or radiation-sensitive resin composition containing the resin obtained by the method for producing the above resin according to the examples, excellent resolution can be obtained in ultrafine pattern formation, and the LWR performance is excellent.

Claims

1. A method for producing a polymer, comprising a step of polymerizing a monomer (a) represented by the following general formula (I) with a monomer (b) different from the monomer (a), The method for producing a polymer, wherein the polymerization step comprises containing from 10 ppm by mass to 10,000 ppm by mass of a polymerization inhibitor relative to the monomer (a) in the reaction liquid. 【Chemistry 1】 In general formula (I), X represents a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group or a halogenated alkyl group. L １ is -O- or -NR Ｘ - represents. Ｘ represents a hydrogen atom or a monovalent organic group. R １ represents a monovalent organic group. Ra represents a hydrogen atom or a monovalent organic group. １ and Ra may be bonded to each other to form a ring.

2. The method for producing a polymer according to claim 1 , wherein the monomer (b) is represented by the following general formula (II): 【Chemistry 2】 In general formula (II), Rb represents a hydrogen atom or a monovalent organic group. R ２ represents an alkyl group, a halogen atom, a cyano group, an alkylsulfonyl group, an alkoxy group, a nitro group, an acyl group, an alkyl ester group or a halogenated alkyl group. Ar represents an aromatic ring group. R ３ represents an alkyl group, an alkoxy group, an acyloxy group, a halogen atom, a hydroxy group, a carboxy group, or a halogenated alkyl group. p is an integer of 0 to 5. ３ When a plurality of R are present, they may be the same or different. ３ and Rb may be bonded to each other to form a ring.

3. The method for producing a polymer according to claim 1 , wherein in the polymerization step, a polymerization initiator is further contained in the reaction liquid.

4. The method for producing a polymer according to claim 1 , wherein in the polymerization step, the reaction liquid contains at least one solvent selected from the group consisting of ketones, esters, and ethers.

5. The method for producing a polymer according to claim 1 , wherein in the polymerization step, a reaction liquid contains an aqueous solution of a surfactant.

6. The method for producing a polymer according to claim 1, wherein, in the general formula (I), X is a chlorine atom.

7. In the general formula (II), R ２ The method for producing a polymer according to claim 2 , wherein is an alkyl group.

8. The method for producing a polymer according to claim 1 , wherein the polymerization step is carried out at a polymerization temperature of 10° C. or higher and 90° C. or lower.

9. The method for producing a polymer according to claim 1, wherein the weight average molecular weight of the polymer is 5,000 or more and 1,000,000 or less.

10. The method for producing a polymer according to claim 3 , wherein the amount of the polymerization initiator is 5 mass % or less based on the total amount of the monomers.

11. The method for producing a polymer according to any one of claims 1 to 10, wherein the polymer is a polymer for an actinic ray-sensitive or radiation-sensitive resin composition.

12. A step of producing a polymer by the production method according to any one of claims 1 to 10; and mixing the polymer with a solvent.

13. The method for producing an actinic ray-sensitive or radiation-sensitive resin composition according to claim 12, wherein at least one ionic compound is further mixed in the mixing step.

14. The method for producing an actinic ray-sensitive or radiation-sensitive resin composition according to claim 13, wherein the ionic compound is at least one selected from the group consisting of a sulfonium salt and an iodonium salt.

Images