JP7747640B2 - Polymer, resist composition containing the polymer, member manufacturing method using the same, pattern forming method, and reverse pattern forming method - Google Patents

Description

Some aspects of the present invention relate to a polymer used in a resist composition. Some aspects of the present invention also relate to a resist composition containing the polymer, a method for manufacturing a member using the resist composition, a pattern formation method, and a method for forming a reverse pattern.

In recent years, photolithography technology using photoresists has been widely used to manufacture display devices such as liquid crystal displays (LCDs) and organic light-emitting diode (OLED) displays, as well as to form semiconductor devices. The packaging of the above electronic components and products widely uses active energy rays such as i-lines with a wavelength of 365 nm, and longer wavelengths such as h-lines (405 nm) and g-lines (436 nm).

As device integration continues to increase, demand for finer lithography techniques is growing, leading to a trend toward using very short-wavelength light for exposure, such as KrF excimer lasers (wavelength 248 nm), ArF excimer lasers (wavelength 193 nm), extreme ultraviolet (EUV, wavelength 13.5 nm), and electron beams (EB). Because lithography techniques using these short-wavelength light sources, particularly EUV or electron beams, enable single-patterning manufacturing, the need for resist compositions that exhibit high sensitivity to EUV or electron beams is expected to grow even further in the future.

As exposure light sources become shorter in wavelength, resist compositions are required to have improved lithography properties, such as sensitivity to the exposure light source and resolution capable of reproducing fine-dimensional patterns. Chemically amplified resists are known as resist compositions that satisfy such requirements (Patent Document 1).
However, with conventional chemically amplified resists, as the resolution line width of the resist becomes finer, it becomes difficult to sufficiently suppress resist pattern collapse and reduce line edge roughness (LWR) of the line pattern.

To achieve reduced LWR and higher resolution in resists, a method is known in which acid generators with bulky acid anions or acid anions bonded to polymers are used to reduce acid diffusion due to heat. (Patent Documents 2 and 3)

Increasing the crosslink density of negative chemically amplified resists has been proposed as a way to prevent resist pattern collapse. However, this can cause swelling during development, resulting in defects such as bridges, making it difficult to increase crosslink density at high sensitivity while maintaining resolution and pattern performance.

Japanese Patent Application Publication No. 9-90637 JP 2011-53622 A JP 2010-276910 A

Some aspects of the present invention have the objective of providing a polymer for use in a resist composition that exhibits excellent resolution and pattern performance characteristics by significantly suppressing acid diffusion, not only by utilizing an acid generated from an acid generator upon irradiation with a particle beam or electromagnetic wave, particularly an electron beam or EUV, but also by directly utilizing a reaction that occurs upon irradiation with an electron beam or EUV, etc., simultaneously with an acid-catalyzed reaction.
An object of some aspects of the present invention is to provide a resist composition containing the above polymer, a method for manufacturing a member using the resist composition, a method for forming a pattern, and a method for forming a reverse pattern.

As a result of intensive research conducted by the present inventors in order to solve the above-mentioned problems, they discovered that by using a polymer in a resist composition that includes a unit A having a specific onium salt structure in which the anion is a monovalent organic group that has at least one selected from the group consisting of a hydroxyl group and a sulfanyl group, and a unit B having a specific structure, it is possible to achieve high sensitivity and suppress line-wise roughness (LWR), and have completed several aspects of the present invention.
More specifically, the inventors have discovered that when a resist composition containing the polymer is irradiated with particle beams, electromagnetic waves, or the like, the following occurs: First, the unit A decomposes, causing a major polarity change from ionic to nonionic. At the same time, the decomposition of the unit A generates an acid, which then causes an intramolecular crosslinking reaction between the hydroxyl groups in the unit B and/or between the unit A and the unit B. When the anion of the onium salt structure contained in the unit A is an anion having an organic group containing a hydroxyl group or a sulfanyl group, a portion of the anion bonds with the hydroxyl group or sulfanyl group in the anion and the unit B via an acid-catalyzed reaction, becoming incorporated into the polymer and becoming an acid of the polymer anion. Therefore, a resist composition containing the polymer can suppress acid diffusion, exhibit high sensitivity, and suppress line-wise roughness (LWR).

One embodiment of the present invention that solves the above-mentioned problems is a polymer comprising: a unit A that has a specific onium salt structure having, as an anion, a monovalent organic group having at least one selected from the group consisting of a hydroxyl group and a sulfanyl group, and that generates an acid when irradiated with a particle beam or electromagnetic wave; and a unit B that has a structure that bonds via an acid-catalyzed reaction.
The unit A is represented by the following formula (1).

(In the above general formula (1), R ¹ is any one selected from the group consisting of a hydrogen atom; a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms; and a linear, branched, or cyclic alkenyl group having 1 to 6 carbon atoms; and at least one hydrogen atom in the alkyl group and alkenyl group in R ¹ may be substituted with a substituent,
L is any one selected from the group consisting of a direct bond, a carbonyloxy group, a carbonylamino group, a phenylenediyl group, a naphthalenediyl group, a phenylenediyloxy group, a naphthalenediyloxy group, a phenylenediylcarbonyloxy group, a naphthalenediylcarbonyloxy group, a phenylenediyloxycarbonyl group, and a naphthalenediyloxycarbonyl group;
Sp is any one of a direct bond; an optionally substituted linear, branched or cyclic alkylene group having 1 to 6 carbon atoms; and an optionally substituted linear, branched or cyclic alkenylene group having 1 to 6 carbon atoms, wherein at least one methylene group in Sp is optionally substituted with a divalent heteroatom-containing group,
M ⁺ is a sulfonium ion or an iodonium ion;
X ⁻ is a monovalent anion having a monovalent organic group in the anion, the monovalent organic group having at least one group selected from the group consisting of a hydroxyl group and a sulfanyl group.

One embodiment of the present invention is a resist composition containing the above polymer.
Another aspect of the present invention is a method for producing a member, the method comprising: a resist film formation step of forming a resist film on a substrate using the resist composition; a photolithography step of exposing the resist film to particle beams or electromagnetic waves; and a pattern formation step of developing the exposed resist film to obtain a photoresist pattern.

One aspect of the present invention is a pattern formation method comprising a resist film formation step of forming a resist film on a substrate using the resist composition, a photolithography step of exposing the resist film using particle beams or electromagnetic waves, and a pattern formation step of developing the exposed resist film to obtain a photoresist pattern.

One aspect of the present invention is a method for forming a reverse pattern, comprising: a resist film formation step of forming a resist film on a substrate using the resist composition; a photolithography step of exposing the resist film using particle beams or electromagnetic waves; a pattern formation step of developing the exposed resist film to obtain a photoresist pattern; a step of applying a reversal pattern composition to cover at least the recesses of the photoresist pattern, and etching the resulting coating to expose the surface of the photoresist pattern; and a step of removing the resist film from the exposed surface portion of the resist pattern to obtain a reverse pattern.

When used as a resist composition, the polymer according to some embodiments of the present invention decomposes upon irradiation with particle beams, electromagnetic waves, or the like, converting from ionic to nonionic, thereby causing a polarity change, and simultaneously generating an acid. The generated acid causes an intramolecular crosslinking reaction between the hydroxyl groups possessed by the unit B and/or between the unit A and the unit B. Furthermore, since the anion of the generated acid contains at least one of a hydroxyl group and a sulfanyl group, it reacts with the unit B in the polymer to become an acid of the polymer anion. Therefore, by utilizing the acid of this polymer anion, an intramolecular crosslinking reaction of the polymer with suppressed acid diffusion can be achieved without using a bulky anion.
As a result, when a pattern is formed using the polymer according to some aspects of the present invention, the sensitivity and line edge roughness (LWR) characteristics are excellent.

In the present invention, the term "particle beam or electromagnetic wave" includes not only electron beam and extreme ultraviolet ray but also ultraviolet ray and the like, but is preferably electron beam or extreme ultraviolet ray.
In the present invention, "particle beam or electromagnetic wave irradiation" refers to irradiating at least a portion of a polymer with particle beams or electromagnetic waves. When a portion of a polymer is irradiated with particle beams or electromagnetic waves, a specific portion of the polymer is excited or ionized, generating active species. The active species induces at least one secondary reaction, such as decomposition of a portion of the unit, addition of the active species to the unit, or elimination of hydrogen from the unit, thereby generating radicals or acids. Here, "active species" refers to radical cations, radicals, electrons, etc.
The present invention will be specifically described below, but the present invention is not limited thereto.

<1> Polymer The polymer according to some embodiments of the present invention is a polymer including a unit A that generates an acid and has a specific onium salt structure, and a unit B that has a structure that bonds via an acid-catalyzed reaction.

A polymer containing the unit A and the unit B is irradiated with particle beams or electromagnetic waves at least in part, whereby the unit A is reduced to generate anions and first radicals from the unit A. Some of the generated anions bond with protons to form acids. The acid acts as a catalyst to cause etherification or thioetherification between the units B and/or between the unit A and the unit B, which can result in a crosslinking reaction. Furthermore, when a unit other than the unit B has at least one of a hydroxyl group and a sulfanyl group, a crosslinking reaction can also occur between at least one of the hydroxyl group and the sulfanyl group of the unit and at least one of the hydroxyl group and the sulfanyl group of the unit B and/or the unit A.
A part of the generated acid anion or the anion of unit A can be bonded to at least one of the hydroxyl group and sulfanyl group of the anion and unit B by the acid to form a polymer acid.

Furthermore, the first radicals generated from unit A can form bonds between themselves and/or between themselves and second radicals generated when the polymer contains a radical-generating unit, potentially causing an intramolecular crosslinking reaction between the units A and/or between the unit A and a radical-generating unit (e.g., unit C, described below). The acid forms a bond between at least one of the hydroxyl group and sulfanyl group of the anion and unit B, thereby suppressing acid diffusion, and therefore the polymer has excellent LWR properties.

(Unit A)
The unit A has a specific onium salt structure. Specifically, the onium salt structure preferably undergoes polarity conversion upon irradiation of at least a portion of the polymer with particle beams or electromagnetic waves, and the anion portion of the onium salt preferably has an organic group containing at least one of a hydroxyl group and a sulfanyl group. That is, the onium salt structure is not particularly limited as long as it has at least one of a hydroxyl group and a sulfanyl group in the anion portion and generates an acid upon reduction of the onium salt. Specific examples include those represented by the following formula (1):
In the present invention, the term "polarity conversion" refers to a change in polarity from ionic to nonionic directly or indirectly due to irradiation with particle beams or electromagnetic waves.

In the above general formula (1), M ⁺ is a sulfonium ion or an iodonium ion, and X ⁻ is a monovalent anion having an organic group containing at least one selected from the group consisting of a hydroxyl group and a sulfanyl group.

L is not particularly limited as long as it can bond the main chain constituting the polymer with the onium salt structure, and examples thereof include any one selected from the group consisting of a direct bond, a carbonyloxy group, a carbonylamino group, a phenylenediyl group, a naphthalenediyl group, a phenylenediyloxy group, a naphthalenediyloxy group, a phenylenediylcarbonyloxy group, a naphthalenediylcarbonyloxy group, a phenylenediyloxycarbonyl group, and a naphthalenediyloxycarbonyl group.
As L, a carbonyloxy group or the like is preferred from the viewpoint of ease of synthesis.

Sp is not particularly limited as long as it can serve as a spacer between L and the onium salt, but may be, for example, a direct bond; an optionally substituted linear, branched, or cyclic alkylene group having 1 to 6 carbon atoms; or an optionally substituted linear, branched, or cyclic alkenylene group having 1 to 6 carbon atoms, and at least one methylene group in Sp may be substituted with a divalent heteroatom-containing group.

Examples of the linear alkylene group having 1 to 6 carbon atoms for Sp include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, and an n-hexylene group.
Examples of the branched alkylene group having 1 to 6 carbon atoms for Sp include an isopropylene group, an isobutylene group, a tert-butylene group, an isopentylene group, a tert-pentylene group, and a 2-ethylhexylene group.

Examples of the cyclic alkylene group having 1 to 6 carbon atoms for Sp include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group.
At least one methylene group in Sp may be substituted with a divalent heteroatom-containing group. Examples of the divalent heteroatom-containing group include groups selected from the group consisting of -O-, -CO-, -COO-, -OCO-, -O-CO-O-, -NHCO-, -CONH-, -NH-CO-O-, -O-CO-NH-, -NH-, -N(R ^Sp )-, -N(Ar ^Sp )-, -S-, -SO-, and -SO ₂ -. Examples of R ^Sp include linear, branched, or cyclic alkyl groups having 1 to 12 carbon atoms, and examples of Ar ^Sp include aryl groups having 12 or less carbon atoms, such as phenyl and naphthyl groups. The number of carbon atoms in the alkylene group in Sp does not include the number of carbon atoms of any substituents that Sp may have.

Examples of the substituent that Sp may have (hereinafter also referred to as "first substituent") include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; a hydroxy group; a linear or cyclic alkyl group having 1 to 12 carbon atoms; an alkyl group having in its skeleton one heteroatom-containing group selected from the group consisting of -O-, -CO-, -COO-, -OCO-, -O-CO-O-, -NHCO-, -CONH-, -NH-CO-O-, -O-CO-NH-, -NH-, -N(R ^Sp )-, -N(Ar ^Sp )-, -S-, -SO-, and -SO ₂ ^-, in place of at least one methylene group of the alkyl group; an aryl group; and a heteroaryl group.
Examples of the alkyl group and the alkyl group containing a heteroatom-containing group in the skeleton as the first substituent of Sp include alkyl groups in which the alkylene group of Sp is monovalent.
Examples of the aryl group as the first substituent of Sp include the same as those described above for Ar 1 ^Sp .
Examples of the heteroaryl group as the first substituent of Sp include groups having a skeleton such as furan, thiophene, pyrrole, imidazole, pyran, pyridine, pyrimidine, and pyrazine.
Sp may be a direct bond, but preferably forms a spacer structure to facilitate molecular movement, in consideration of the radical rebonding between units A and the crosslinking reaction between units B. Preferred examples include an alkylene group, an alkyleneoxy group, and an alkylenecarbonyloxy group.

R ¹ is any one selected from the group consisting of a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, and a linear, branched, or cyclic alkenyl group having 1 to 6 carbon atoms, and at least one hydrogen atom in the alkyl group and alkenyl group in R ¹ may be substituted with a substituent. Examples of the substituent ^that R 1 may have include the same as those for the first substituent.

Examples of the linear alkyl group having 1 to 6 carbon atoms for R ¹ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl group.
Examples of the branched alkyl group having 1 to 6 carbon atoms for R ¹ include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a tert-pentyl group, and a 2-ethylhexyl group.
Examples of the cyclic alkyl group having 1 to 6 carbon atoms for R ¹ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

Examples of the linear, branched, or cyclic alkenyl group having 1 to 6 carbon atoms for R ¹ include the linear alkyl groups, branched alkyl groups, and cyclic alkyl groups shown above in which at least one carbon-carbon single bond has been replaced with a carbon-carbon double bond.
Furthermore, ^R1 may be a fluorinated alkyl group or a fluorinated alkenyl group in which at least one hydrogen atom in the alkyl group or alkenyl group is substituted with a fluorine atom. All hydrogen atoms may be substituted with the first substituent. As the fluorinated alkyl group, a trifluoromethyl group or the like is preferred.

As the unit A, those in which R ¹ in the above formula (1) is a hydrogen atom or a linear alkyl group, and L is a carbonyloxy group, a carbonylamino group, or a phenylenediyl group are preferred.
Furthermore, as the unit A, a unit in which L is a carbonyloxy group or a carbonylamino group, Sp is a direct bond, and ^R1 is a methyl group, and the methyl group has at least one of an alkyl group having 1 to 4 carbon atoms, a halogen atom, and an aryl group among the first substituents, is preferred from the viewpoint of LWR. Particularly preferred examples of ^R1 having the first substituent include an ethyl group, an isopropyl group, a butyl group, a halogenated methyl group (e.g., a fluoromethyl group, a chloromethyl group, a bromomethyl group, an iodomethyl group), and a benzyl group.

M ⁺ is a sulfonium cation or iodonium cation having a bond bonded to Sp, and specific examples thereof include those represented by the following general formulae (a1) and (a2).

In the above general formula, R ^6a is any one selected from the group consisting of an optionally substituted linear, branched, or cyclic alkylene group having 1 to 6 carbon atoms; an optionally substituted linear, branched, or cyclic alkenylene group having 1 to 6 carbon atoms; an optionally substituted arylene group having 6 to 14 carbon atoms; an optionally substituted heteroarylene group having 4 to 12 carbon atoms; and a direct bond.
Examples of the linear, branched or cyclic alkylene group of R ^6a include the same alkylene groups as those of Sp.
Examples of the linear, branched or cyclic alkenylene group of R ^6a include the same alkenylene groups as those of Sp above.

Examples of the arylene group having 6 to 14 carbon atoms for R ^6a include a phenylene group and a naphthylene group.
Examples of the heteroarylene group having 4 to 12 carbon atoms for R ^6a include divalent groups having a skeleton such as furan, thiophene, pyrrole, imidazole, pyran, pyridine, pyrimidine, pyrazine, indole, purine, quinoline, isoquinoline, chromene, thianthrene, dibenzothiophene, phenothiazine, phenoxazine, xanthene, acridine, phenazine, and carbazole.
Examples of the alkyl group, alkenyl group, aryl group and heteroaryl group of R ^6b include the alkylene group, alkenylene group, arylene group and heteroarylene group of R ^6a that have become monovalent.

Examples of the substituents of R ^6a and R ^6b include the same substituents as the first substituent that may be possessed by the above-mentioned Sp.
In the above formula (a1), R ^6a and any two of the two R ^6b may form a ring structure together with the sulfur atom to which they are bonded, either directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen-containing group, and a methylene group.
Examples of the divalent nitrogen atom-containing group include those divalent hetero atom-containing groups that contain a nitrogen atom, and specific examples include -NHCO-, -CONH-, -NH-CO-O-, -O-CO-NH-, -NH-, -N(R ^Sp )-, and -N(Ar ^Sp )-.

Examples of the sulfonium cation represented by M ⁺ include those having the structure shown below and having a bond bonded to the Sp at any position. The compound shown below may have the same substituent as the first substituent at the positions corresponding to ^R6a and ^R6b .

X 1 ⁻ is a monovalent anion having an organic group containing at least one of a hydroxyl group and a sulfanyl group.
The hydroxyl group is preferably derived from any one selected from the group consisting of primary alcohols, secondary alcohols, and tertiary alcohols, and the sulfanyl group is preferably derived from any one selected from the group consisting of primary thiols, secondary thiols, and tertiary thiols.
From the steric viewpoint of bonding with the unit B, the hydroxyl group is more preferably derived from any one selected from the group consisting of a primary alcohol, a secondary alcohol, a primary thiol, and a secondary thiol.
In view of reactivity with unit B in the presence of an acid catalyst, it is preferable that the hydroxyl group is not a phenolic hydroxyl group.

X ⁻ is preferably any one selected from the group consisting of: an alkyl sulfate anion having at least one hydroxyl group and a sulfanyl group; an aryl sulfate anion having at least one hydroxyl group and a sulfanyl group; an alkylsulfonate anion having at least one hydroxyl group and a sulfanyl group; an arylsulfonate anion having at least one hydroxyl group and a sulfanyl group; an alkylcarboxylate anion having at least one hydroxyl group and a sulfanyl group; an arylcarboxylate anion having at least one hydroxyl group and a sulfanyl group; a dialkylsulfonylimide anion having at least one hydroxyl group and a sulfanyl group; and a trialkylsulfonate methide anion having at least one hydroxyl group and a sulfanyl group; and a tetrakisphenylborate anion having at least one hydroxyl group and a sulfanyl group.

In addition, at least one hydrogen atom of the alkyl group and aryl group in ^X- may be substituted with a fluorine atom and/or an iodine atom, but from the viewpoint of reactivity in bonding with the unit B, it is preferable that the number of fluorine and iodine atom substitutions is small.
^X- is more preferably either an alkylsulfonate anion having at least one hydroxyl group and one sulfanyl group or an arylsulfonate anion having at least one hydroxyl group and one sulfanyl group, wherein at least one hydrogen atom of the alkyl group of the alkylsulfonate anion or the aryl group of the arylsulfonate anion may be substituted with a fluorine atom.

The alkyl sulfate anion having at least one hydroxyl group preferably has 1 to 12 carbon atoms.
The alkyl sulfate anion having at least one sulfanyl group preferably has 1 to 12 carbon atoms.
The alkyl sulfate anion may have multiple hydroxyl groups and sulfanyl groups.

The aryl sulfate anion having at least one hydroxyl group preferably has 4 to 12 carbon atoms.
The aryl sulfate anion having at least one sulfanyl group preferably has 4 to 12 carbon atoms.
The aryl sulfate anion may have multiple hydroxyl groups and sulfanyl groups.

The alkylsulfonate anion having at least one hydroxyl group preferably has 1 to 12 carbon atoms.
The alkylsulfonate anion having at least one sulfanyl group preferably has 1 to 12 carbon atoms.
The alkylsulfonate anion may have a plurality of hydroxyl groups and sulfanyl groups.

The arylsulfonate anion having at least one hydroxyl group preferably has 4 to 12 carbon atoms.
The arylsulfonate anion having at least one sulfanyl group preferably has 4 to 12 carbon atoms.
The arylsulfonate anion may have a plurality of hydroxyl groups and sulfanyl groups.

The alkylcarboxylate anion having at least one hydroxyl group preferably has 2 to 12 carbon atoms.
The alkylcarboxylate anion having at least one sulfanyl group preferably has 2 to 12 carbon atoms.
The alkylcarboxylate anion may have multiple hydroxyl groups and sulfanyl groups.

The arylcarboxylate anion having at least one hydroxyl group preferably has 5 to 12 carbon atoms.
The arylcarboxylate anion having at least one sulfanyl group preferably has 5 to 12 carbon atoms.
The arylcarboxylate anion may have multiple hydroxyl groups and sulfanyl groups.

The dialkylsulfonylimide anion having at least one hydroxyl group preferably has 1 to 12 carbon atoms.
The dialkylsulfonylimide anion having at least one sulfanyl group preferably has 1 to 12 carbon atoms.
The dialkylsulfonylimide anion may have a plurality of hydroxyl groups and sulfanyl groups.

The trialkylsulfonate methide anion having at least one hydroxyl group preferably has 1 to 12 carbon atoms.
The trialkylsulfonate methide anion having at least one sulfanyl group preferably has 1 to 12 carbon atoms.
The trialkylsulfonate methide anion may have a plurality of hydroxyl groups and sulfanyl groups.

The tetrakisphenylborate anion having at least one hydroxyl group preferably has 25 to 30 carbon atoms.
The tetrakisphenylborate anion having at least one sulfanyl group preferably has 25 to 30 carbon atoms.
The tetrakisphenylborate anion may have a plurality of hydroxyl groups and sulfanyl groups.

Examples of the above X ⁻ include the following.

The above unit A is preferably represented by the following formula (3).

In the general formula (IV), L, Sp, and X 1 ^- are the same as L, Sp, and X 1 ^- in the general formula (1), respectively, and R ^6a and R ^6b are the same as R ^6a and R ^6b in the general formula (a1), respectively.

Furthermore, the polymer according to one embodiment of the present invention preferably includes a unit A in which M ⁺ X ⁻ in general formula (1) is an onium salt structure represented by either general formula (11) or general formula (12). When a polymer with this configuration is used in a resist composition, it is preferable to expose the resist composition to second active energy rays having lower energy than the first active energy rays after irradiation with the particle beam or electromagnetic wave (hereinafter also referred to as "first active energy rays"). The second active energy rays are preferably ultraviolet light or visible light. The resist composition includes a polymer that includes a unit A having a specific onium salt structure with an acetal moiety or a thioacetal moiety (hereinafter also referred to as "acetal moiety or thioacetal moiety"), and a unit B having a structure that bonds via an acid-catalyzed reaction. Irradiating the resist composition containing the polymer with the first active energy rays decomposes the onium salt structure of the unit A, thereby generating an acid. When the onium salt structure of the unit A in the composition irradiated with the first actinic energy ray using this acid as a catalyst has a (thio)acetal moiety, the structure is changed by the acid to convert it into a ketone derivative that absorbs the second actinic energy ray. By exposing the composition in which the ketone derivative has been generated to the second actinic energy ray, acid is generated with high efficiency, resulting in high sensitivity.

In the unit A related to the polymer that is one embodiment of the present invention, the onium salts of the general formulae (11) and (12) have a specific structure of a (thio)acetal moiety and a dibenzothiophenium skeleton, and therefore have high decomposition efficiency with respect to the first active energy ray and high absorption with respect to irradiation with the second active energy ray after irradiation with the first active energy ray.
Furthermore, when the onium salt structure of unit A in a polymer according to one embodiment of the present invention is an onium salt structure represented by the general formulas (11) and (12), unit A does not exhibit significant absorption of the second active energy ray, such as ultraviolet light or visible light. Meanwhile, the acid generated by the first active energy ray deprotects the (thio)acetal moiety of the onium salt structure, converting it to a ketone derivative without impairing the onium salt structure's function as a photoacid generator. The ketone derivative contains a dibenzothiophenium structure having a fused ring structure, which increases the conjugation length, thereby easily shifting the absorption wavelength to a longer wavelength and absorbing the second active energy ray. Since the ketone derivative is generated in the resist film in the exposed area irradiated with the first active energy ray, further irradiation with the second active energy ray can increase the amount of acid generated in the exposed area irradiated with the first active energy ray.
In the present invention, the second active energy ray is preferably ultraviolet light or visible light having a wavelength of 365 nm or more. The second active energy ray is more preferably 420 nm or less. The first active energy ray preferably has higher energy than the second active energy ray and is not particularly limited as long as it can generate an active species such as an acid from the onium salt of unit A. Preferred examples of the first active energy ray include KrF excimer laser light, ArF excimer laser light, electron beams, and extreme ultraviolet light (EUV).

In the formulas (11) and (12), each R ¹⁴ is independently any one selected from the group consisting of an alkyl group, a hydroxy group, a mercapto group, an alkoxy group, an aryloxycarbonyl group, a heteroaryloxycarbonyl group, an arylsulfanylcarbonyl group, a heteroarylsulfanylcarbonyl group, an arylsulfanyl group, a heteroarylsulfanyl group, an alkylsulfanyl group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, a (poly)alkyleneoxy group, an alkylamino group, and a dialkylamino group.
R ¹⁷ and R ¹⁸ are each independently any one selected from the group consisting of an alkyl group, a hydroxy group, a mercapto group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, a heteroarylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a heteroaryloxycarbonyl group, an arylsulfanylcarbonyl group, a heteroarylsulfanylcarbonyl group, an arylsulfanyl group, a heteroarylsulfanyl group, an alkylsulfanyl group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, an alkylsulfinyl group, an arylsulfinyl group, a heteroarylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a heteroarylsulfonyl group, an arylsulfonyl group, a heteroarylsulfonyl group, a (poly)alkyleneoxy group, an alkylamino group, a dialkylamino group, a nitro group, and a halogen atom.
When R ¹⁴ , R ¹⁷ and R ¹⁸ each have a carbon atom, the number of carbon atoms is 1 to 12, and when R ¹⁴ , R ¹⁷ and R ¹⁸ each have a hydrogen atom, the hydrogen atom may be substituted with a substituent (hereinafter also referred to as a "second substituent").

The alkyl group in R ¹⁴ , R ¹⁷ and R ¹⁸ may be linear, branched or cyclic, and specific examples thereof include the same as the alkyl group in R ^e as the second substituent described below. In addition, the alkyl group moiety such as an alkoxy group, an alkylcarbonyl group or an alkoxycarbonyl group in R ¹⁴ , R ¹⁷ and R ¹⁸ may also be the same as the alkyl group in R ¹ .
Examples of the aryl group and heteroaryl group in R ¹⁴ , R ¹⁷ , and R ¹⁸ include the same as the aryl group and heteroaryl group in R ^19. Examples of the aryl group moiety such as the arylcarbonyl group and aryloxycarbonyl group in R ¹⁷ and R ¹⁸ include the same as the aryl group in R ^19. Examples of the heteroaryl group moiety such as the heteroarylcarbonyl group and heteroaryloxycarbonyl group in ^R 17 and R ¹⁸ include the same as the heteroaryl group in R ^1. From the viewpoint of synthesis, it is preferable that R ¹⁷ and R ¹⁸ are substituents that do not have a heteroaryl group moiety such as the heteroarylcarbonyl group and heteroaryloxycarbonyl group.
When the onium salt structure represented by the above formula (11) or (12) has two or more R ¹⁴ , two of the R ¹⁴ may be linked to each other to form a ring structure.

Examples of the (poly)alkyleneoxy group in R ¹⁴ , R ¹⁷ and R ¹⁸ include a polyethyleneoxy group and a polypropyleneoxy group.
Examples of the halogen atom in R ¹⁷ and R ¹⁸ include a fluorine atom, a chlorine atom, and an iodine atom.

When R ¹⁴ , R ¹⁷ and R ¹⁸ each have carbon, the number of carbon atoms is preferably 1 to 12, and each may have a second substituent. In addition, the carbon-carbon single bond in the alkyl group of R ² , R ³ and R ⁴ may be replaced with a carbon-carbon double bond.
The second substituent that R ¹⁴ , R ¹⁷ and R ¹⁸ may have includes a hydroxy group, a cyano group, a mercapto group, a carboxy group, an alkyl group (—R ^e ), an alkoxy group (—OR ^e ), an acyl group (—COR ^e ), an alkoxycarbonyl group (—COOR ^e ), an aryl group (—Ar), an aryloxy group (—OAr), an amino group, an alkylamino group (—NHR ^e ), a dialkylamino group (—N(R ^e ) ₂ ), an arylamino group (—NHAr), a diarylamino group (—N(Ar) ₂ ), an N-alkyl-N-arylamino group (—NR ^e Ar), a phosphino group, a silyl group, a halogen atom, a trialkylsilyl group (—Si—(R ^e ) ₃ ), a silyl group in which at least one alkyl group of the trialkylsilyl group is substituted with Ar, an alkylsulfanyl group (—SR ^e ) and arylsulfanyl group (—SAr), but are not limited to these.
R ^e and Ar are described below.

The R ^e in the second substituent is preferably an alkyl group having 1 or more carbon atoms, and more preferably having 20 or less carbon atoms. Specific preferred examples of the alkyl group having one or more carbon atoms include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, and n-decyl groups; branched alkyl groups such as isopropyl, isobutyl, tert-butyl, isopentyl, tert-pentyl, and 2-ethylhexyl groups; alicyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantan-1-yl, adamantan-2-yl, norbornan-1-yl, and norbornan-2-yl groups; silyl-substituted alkyl groups in which one of the hydrogen atoms is substituted with a trialkylsilyl group such as trimethylsilyl, triethylsilyl, and dimethylethylsilyl groups; and alkyl groups in which at least one of the hydrogen atoms is substituted with a cyano group, a fluoro group, or the like. The carbon-carbon single bond in the alkyl group may be replaced with a carbon-carbon double bond.

In the second substituent, Ar is preferably an aryl group or a heteroaryl group. A heteroaryl group is an aryl group containing one or more heteroatoms in the ring structure. Specific examples of Ar preferably include those having 20 or less carbon atoms, such as a phenyl group, a biphenyl group, a terphenyl group, a quaterphenyl group, a naphthyl group, an anthryl group, a phenanthrenyl group, a pentalenyl group, an indenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a heptalenyl group, a naphthacenyl group, a pyrenyl group, a chrysenyl group, a tetracenyl group, a furanyl group, a thienyl group, a pyranyl group, a sulfanylpyranyl group, a pyrrolyl group, an imidazoyl group, an oxazolyl group, a thiazolyl group, a pyrazoyl group, a pyridyl group, an isobenzofuranyl group, a benzofuranyl group, an isochromenyl group, a chromenyl group, an indolyl group, an isoindolyl group, a benzimidazoyl group, a xanthenyl group, an aquadinyl group, and a carbazoyl group.

When R ¹⁴ , R ¹⁷ and R ¹⁸ have the second substituent, the number of carbon atoms of R ¹⁴ , R ¹⁷ and R ¹⁸ is preferably 1 to 12, including the number of carbon atoms of the second substituent.

The onium salt structure of the polymer according to one embodiment of the present invention preferably has at least one R ^14. Furthermore, it is preferable that at least one R ¹⁴ is a hydroxy group or an alkoxy group. Furthermore, it is preferable that R ¹⁴ is located at the ortho or para position relative to the bonding position of the (thio)acetal moiety. Having a hydroxy group or an alkoxy group at the ortho or para position as R ¹⁴ in the onium salt structure tends to increase the absorption of the second actinic energy ray when the ketone derivative is formed. In particular, a hydroxy group is more preferable because it improves the affinity for an alkaline developer and therefore improves the solubility of the onium salt during development.
Generally, when a substituent is added to the cation of the onium salt structure, the onium salt cation structure becomes three-dimensionally larger, which may improve hydrophobicity and cause a dissolution inhibition effect during development. Therefore, it is preferable to have a structure in which the absorption wavelength of the ketone derivative after deprotection of the (thio)acetal moiety is longer without having a hydrophobic substituent that tends to have a low affinity for alkaline developers, thereby increasing the absorption of the second actinic ray. Furthermore, since a basic substituent deactivates the generated acid and inhibits the decomposition of the acid-dissociable group, it is not preferable to introduce a basic substituent. For these reasons, it is preferable that the cation of the onium salt structure related to the polymer, which is one embodiment of the present invention, does not have a substituent containing an aromatic ring or an alicyclic structure in R ¹⁴ , R ¹⁷ , or R ¹⁸ , and does not have a basic group such as an amino group that reacts with the generated acid. Furthermore, it is preferable that the molecular weight of the cation portion of the onium salt structure is 500 or less. It is more preferable that the cation of the onium salt structure in the polymer which is one embodiment of the present invention does not have a basic group such as an amino group in R ¹⁷ and R ¹⁸ , including R ¹⁴ .
When there are multiple R ^14s , it is preferable that at least one of R ^14s is a hydroxy group or an alkoxy group and is located at the ortho or para position relative to the bonding position of the (thio)acetal moiety. Furthermore, when there are multiple R ^14s , as long as at least one of R ^14s is a hydroxy group or an alkoxy group, the other R ^4s do not have to be hydroxy groups or alkoxy groups. From the viewpoint of lengthening the absorption wavelength of the ketone derivative generated by the acid, it is more preferable that two or more R ^14s are substituents that donate electrons to the aromatic ring to which they are bonded. It is even more preferable that R ^14s are located at two or more positions that are ortho or para positions relative to the bonding position of the (thio)acetal moiety.

R ¹⁹ is any one selected from the group consisting of: an optionally substituted linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms; an optionally substituted linear, branched, or cyclic alkenyl group having 1 to 12 carbon atoms; an optionally substituted aryl group having 6 to 14 carbon atoms; and an optionally substituted heteroaryl group having 4 to 12 carbon atoms.

Specific examples of the linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms for R ¹⁹ include alkyl groups such as methyl, ethyl, n-propyl, n-butyl, isopropyl, t-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantan-1-yl, adamantan-2-yl, norbornan-1-yl, and norbornan-2-yl.

In the alkyl group of ^R19 , at least one methylene group may be substituted with a divalent heteroatom-containing group. The divalent heteroatom-containing group is a group containing at least one selected from the group consisting of -O-, -CO-, -COO-, -OCO-, -O-CO-O-, -NHCO-, -CONH-, -NH-CO-O-, -O-CO-NH-, -NH-, -N( ^{R e} )-, -N(Ar)-, -S-, -SO-, and -SO ₂ -. However, it is preferable that the sulfur atom (S ⁺ ) of the sulfonium group is not directly bonded to the heteroatom-containing group but is bonded to a divalent hydrocarbon group. R ^e and Ar will be described later.
The alkenyl group of R ¹⁹ includes the above alkyl groups in which at least one carbon-carbon single bond has been substituted with a carbon-carbon double bond.

Specific examples of the aryl group having 6 to 14 carbon atoms in R ¹⁹ which may have a substituent include monocyclic aromatic hydrocarbon groups and condensed polycyclic aromatic hydrocarbon groups in which at least two such monocyclic aromatic hydrocarbons are condensed. These aryl groups may have a substituent.
Examples of the monocyclic aromatic hydrocarbon group include groups having a skeleton such as benzene.
Examples of the condensed polycyclic aromatic hydrocarbon group include groups having a skeleton such as indene, naphthalene, azulene, anthracene, and phenanthrene.

Examples of the heteroaryl group having 4 to 12 carbon atoms for R ¹⁹ which may have a substituent include those which contain at least one atom selected from an oxygen atom, a nitrogen atom and a sulfur atom in the skeleton, instead of at least one carbon atom of the above aryl group.

Examples of the heteroaryl group include a monocyclic aromatic heterocyclic group and a fused polycyclic aromatic heterocyclic group in which at least one of the monocyclic aromatic heterocyclic rings is fused with the aromatic hydrocarbon group or aliphatic heterocyclic group, etc. These aromatic heterocyclic groups may have a substituent.
Examples of the monocyclic aromatic heterocyclic group include groups having a skeleton such as furan, pyrrole, imidazole, pyran, pyridine, pyrimidine, and pyrazine.

Fused polycyclic aromatic heterocyclic groups include groups having skeletons such as indole, purine, quinoline, isoquinoline, chromene, phenoxazine, xanthene, acridine, phenazine, and carbazole.

Examples of the substituent in R ¹⁹ (hereinafter also referred to as the "third substituent") include the same as those described above for the second substituent.

When the alkyl group or the like of R ¹⁹ has the third substituent and the onium salt is a low molecular weight compound, the number of carbon atoms of R ¹⁹ is preferably 1 to 20, including the number of carbon atoms of the third substituent.

R ¹⁹ and either the benzene ring to which R ² is bonded or the benzene ring to which R ³ is bonded may form a ring structure together with the sulfur atom to which they are bonded, either directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom-containing group and a methylene group;
Examples of the "nitrogen atom-containing group" include divalent groups containing a nitrogen atom, such as an aminodiyl group (-NH-), an alkylaminodiyl group (-NR ^e -), an arylaminodiyl group (-NAr-), etc. R ^e and Ar are the same as R ^e and Ar of the third substituent.

R ¹⁹ is preferably an aryl group from the viewpoint of improving stability.

The R ¹⁹ and either the benzene ring to which the R ¹⁸ is bonded or the benzene ring to which the R ¹⁷ is bonded may form a ring structure together with the sulfur atom to which they are bonded, either directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom-containing group and a methylene group.

When R ¹⁴ , R ¹⁷ , and R ¹⁸ each contain a methylene group, at least one of the methylene groups may be substituted with a divalent heteroatom-containing group. However, it is preferable that there is no continuous linkage of heteroatoms such as -O-O-, -S-S-, and -O-S-. Examples of R ¹⁴ , R ¹⁷ , and R ¹⁸ in which at least one methylene group may be substituted with a divalent heteroatom-containing group include polyalkyleneoxy groups such as a 2-methoxyethoxy group, a 2-ethoxyethoxy group, a 2-(2-methoxyethoxy)ethoxy group, a 2-(2-ethoxyethoxy)ethoxy group, a 2-methoxypropoxy group, and a 3-methoxypropoxy group; polyalkylenethio groups such as a 2-methylthioethylthio group and a 2-ethylthioethylthio group; and polyalkyleneoxythio groups such as a 2-methylthioethoxy group and a 2-ethoxyethylthio group. However, some aspects of the present invention are not so limited.

Preferably, R ¹⁵ and R ¹⁶ are each independently an optionally substituted linear, branched or cyclic alkyl group having 1 to 12 carbon atoms; an optionally substituted linear, branched or cyclic alkenyl group having 1 to 12 carbon atoms; an optionally substituted aryl group having 6 to 14 carbon atoms; or an optionally substituted heteroaryl group having 4 to 12 carbon atoms, and these are preferably selected from the same options as for R ¹⁹ .
Examples of the substituents as R ¹⁵ and R ¹⁶ (hereinafter also referred to as "fourth substituents") include the same as those listed above for the second substituent.
R ¹⁵ and R ¹⁶ may be bonded to each other directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, and an alkylene group to form a ring structure;
At least one methylene group in R ¹⁵ and R ¹⁶ may be substituted with a divalent heteroatom-containing group.
From the viewpoint of synthesis, it is preferred that R ¹⁵ and R ¹⁶ are the same.

^L3 is any one selected from the group consisting of a direct bond; a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms; an alkenylene group having 2 to 12 carbon atoms; a sulfinyl group, a sulfonyl group, and a carbonyl group.

Any one hydrogen atom among R ¹⁴ , R ¹⁸ and R ¹⁹ is replaced by a bond to Sp in the above general formula (1).

Y is an oxygen atom or a sulfur atom.

q is an integer of 0 to 4, f is an integer of 0 to 3, g is an integer of 1 to 5, j is an integer of 0 to 2, and k is an integer of 1 to 4.
However, when R ¹⁹ and either the benzene ring to which R ¹⁸ is bonded or the benzene ring to which R ¹⁷ is bonded together with the sulfur atom form a ring structure, in the general formula (11), q is 0 to 3 or j is 0 to 2, and in the general formula (12), q is 0 to 3 or j is 0 to 1.
At least one of the benzene rings in the general formulae (11) and (12) may be a 6-membered heteroaromatic ring having a heteroatom in the ring, and when the benzene ring bonded to R ¹⁴ in the general formulae (11) and (12) is the heteroaromatic ring, k may be 0 to 4.
When the general formulae (11) and (12) have two or more R ^{14 s} , two of the R ^{14 s} may be linked to each other to form a ring structure.
X ^{1 −} is selected from the same options as X 1 ⁻ in the general formula (1) above.

In some embodiments of the polymer of the present invention, the onium salt structure contained in unit A can be exemplified by one having the sulfonium cation shown below. The wavy line in the sulfonium cation shown below indicates the bonding site with Sp in formula (1) above, and when there are multiple wavy lines in the same structure, any one of them is bonded to the above Sp. However, some embodiments of the present invention are not limited to this.

The anion of the above unit A is preferably highly hydrophilic in order to improve contrast during photoresist pattern formation. Specific examples include alkyl sulfate anions, aryl sulfate anions, alkyl sulfonate anions, aryl sulfonate anions, alkyl carboxylate anions, and aryl carboxylate anions. These anions contain at least one hydroxyl group and one sulfanyl group.

The polymer according to one embodiment of the present invention may contain two or more types of the unit A. For example, it is preferable to use one unit as a photoacid generator unit A (hereinafter also referred to as "unit A1") and the other as a photodegradable base unit A (hereinafter also referred to as "unit A2"). ^X- in the photodegradable base unit A2 is preferably an alkyl carboxylate anion or an aryl carboxylate anion. The photodegradable base unit A2 is preferably used in combination with the photoacid generator unit A1. Incidentally, the polymer containing unit A2 has the effect of reducing LWR, and is therefore effective when high resolution is required.
When the polymer contains two or more types of the unit A, units having the same M ⁺ X ^- moiety but different substituents such as R ¹ and L may be used.

The onium salts related to the polymers that are some embodiments of the present invention preferably have a molar absorption coefficient at 365 nm of less than 1.0×10 ⁵ cm ² /mol, more preferably less than 1.0×10 ⁴ cm ² /mol.
Furthermore, the ketone derivative in which the (thio)acetal moiety of the onium salt according to some embodiments of the present invention is deprotected preferably has a molar absorption coefficient at 365 nm of 1.0 × 10 ⁵ cm ² /mol or more, more preferably 1.0 × 10 ⁶ cm ² /mol or more.
The molar absorption coefficient at 365 nm of the ketone derivative is preferably 5 times or more, more preferably 10 times or more, and even more preferably 20 times or more, the molar absorption coefficient at 365 nm of the onium salt related to the polymer that is some embodiment of the present invention.
To achieve the above properties, an onium salt represented by the above formula (11) or (12) may be used.

(Method for synthesizing monomer for unit A)
A method for synthesizing the sulfonium salt structure contained in unit A of the polymer, which is one embodiment of the present invention, will be described below, although the present invention is not limited thereto.

When the target sulfonium salt structure is a (meth)acrylate monomer that does not contain a (thio)acetal moiety, for example, the synthesis method shown below can be used. First, a diaryl sulfoxide having an R ^6b group and a benzene having a hydroxyl group (R ^6a group) are subjected to a Friedel-Crafts reaction using a Bronsted acid to obtain a hydroxyaryl diaryl sulfoxide. Next, the target sulfonium salt is obtained using a basic catalyst and (meth)acrylic acid chloride. In this case, even if the above R ¹ , R ^6a , and R ^6b are substituents other than those exemplified here, they can be similarly obtained as long as they are within the above-mentioned ranges for R ¹ , R ^6a , and R ^6b .

When the desired sulfonium salt structure is a vinyl or isopropenyl monomer that does not contain a (thio)acetal moiety, for example, the synthesis method shown below can be used. First, a diaryl sulfoxide optionally having an R ^6b group is reacted with a sulfoxide having an R ^6b group using a Grignard reagent (R ^6a group) having a vinyl or isopropenyl group to form a sulfonium salt structure, and then the desired sulfonium salt structure is obtained by salt exchange using a salt having a corresponding anion. In this case, even if the above R ¹ , R ^6a , and R ^6b are substituents other than those exemplified here, they can be similarly obtained as long as they are within the above-mentioned ranges for R ¹ , R ^6a , and R ^6b .

When the target sulfonium salt structure contains a (thio)acetal moiety, for example, the synthesis method shown below can be used. First, a dibenzothiophene having optional R ¹⁷ and R ¹⁸ groups and a benzoyl chloride (i = 1 in the following formula) having optional R ¹⁴ groups are subjected to a Friedel-Crafts reaction using a Lewis acid to obtain a benzophenone derivative. Next, the sulfide is oxidized to a sulfoxide, and then a benzene having a hydroxyl group is subjected to a Friedel-Crafts reaction with a Brønsted acid to obtain a sulfonium, and the carbonyl group is acetalized using an alcohol (R ¹⁵ OH) using an acid catalyst. Next, the target oninium salt is obtained using a basic catalyst and (meth)acrylic acid chloride. In this case, even if the above R ¹⁴ , R ¹⁵ , R ¹⁷ , and R ¹⁸ are substituents other than those exemplified here, they can be obtained in the same manner as long as they are within the above-mentioned ranges of R ¹⁴ , R ¹⁵ , R ¹⁷ , and R ¹⁸ .

When the desired sulfonium salt structure contains a (thio)acetal moiety, for example, the following synthesis method can be used. First, a dibenzothiophene having optional ^R17 and ^R18 groups and a benzoyl chloride (i = ¹ in the following formula) having optional R14 groups are subjected to a Friedel-Crafts reaction using a Lewis acid to obtain a benzophenone derivative. Next, the sulfide is oxidized to form a sulfoxide, and then a hydroxyl group-containing benzene and a Brønsted acid are subjected to a Friedel-Crafts reaction to form a sulfonium, after which the carbonyl group is acetalized using an alcohol ( ^R15OH ) using an acid catalyst. Next, a sulfonium salt structure is formed using a Grignard reagent, and then salt exchange is performed with a salt having the corresponding anion to obtain the desired sulfonium salt structure.

(Unit B)
The unit B is not particularly limited as long as it has a structure that allows two molecules to bond together by an acid-catalyzed reaction. For example, a unit in which a compound represented by general formula (I) or (II) is bonded to the Sp group of formula (1) at any position of the compound is preferred.
At least one of the compounds represented by the following general formula (I) or (II) is bonded at any position of the compound to the moiety * in the following formula (2) and contained in the polymer as unit B. When the polymer contains unit B, it becomes possible to improve sensitivity to particle beams or electromagnetic waves.

In the above formula (2), R ¹ , L and Sp are the same as those in the above general formula (1).

In the general formula (I), ^R2 and ^R3 are each independently any one selected from the group consisting of a hydrogen atom, an electron-donating group, and an electron-withdrawing group. It is preferable that at least one of ^R2 and ^R3 is an electron-donating group, as this improves acid reactivity.
E is preferably any one selected from the group consisting of a direct bond; an oxygen atom; a sulfur atom; and a methylene group.

ⁿ¹ is an integer of 0 or 1. ⁿ⁴ and ⁿ⁵ are each an integer of 1 to 2. ⁿ⁴ + ⁿ⁵ is an integer of 2 to 4.
When ⁿ⁴ is 1, ⁿ² is an integer of 0 to 4. When ⁿ⁴ is 2, ⁿ² is an integer of 0 to 6.
When ⁿ⁵ is 1, ⁿ³ is an integer of 0 to 4. When ⁿ⁵ is 2, ⁿ³ is an integer of 0 to 6.
When ⁿ² is 2 or greater and ^R2 is an electron-donating group or an electron-withdrawing group, two ^R2s may form a ring structure together directly by a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen-containing group, and a methylene group.
When ⁿ³ is 2 or more and ^R3 is an electron-donating group or an electron-withdrawing group, two ^R3s may form a ring structure together directly by a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen-containing group, and a methylene group.
In the above formula (I), examples of the divalent nitrogen atom-containing group for forming a ring structure include the same as the divalent nitrogen atom-containing group in the above formula (a1).

In the general formula (II), each ^R4 is independently any one selected from the group consisting of a hydrogen atom, an electron-donating group, and an electron-withdrawing group. At least one of ^R4 is preferably an electron-donating group, since this improves acid reactivity.
^R5 is any one selected from the group consisting of a hydrogen atom; an alkyl group which may have a substituent; and an alkenyl group which may have a substituent; and at least one methylene group in ^R5 may be substituted with a divalent heteroatom-containing group.
Furthermore, ^R5 may form a ring structure together with the benzene ring to which the hydroxymethylene group having ^R5 is bonded.

The alkyl group for ^R5 may be a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms. Specific examples include the same alkyl groups as those for ^R6b .
Examples of the substituent that R ⁵ has include the same as the first substituent that Sp has.

ⁿ⁶ is an integer from 0 to 7;
ⁿ⁷ is 1 or 2. When ⁿ⁷ is 1, n6 is an integer of 0 to 5. When ⁿ⁷ is 2, ⁿ⁶ is an integer of 0 to 7.

When ⁿ⁶ is 2 or more and ^R4 is an electron-donating group or an electron-withdrawing group, two ^R4s may form a ring structure together directly by a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen-containing group, and a methylene group.
In the formula (II), examples of the divalent nitrogen atom-containing group for forming a ring structure include the same as the divalent nitrogen atom-containing group in the formula (a1).

Examples of the electron-donating groups ^R2 , ^R3 , and ^R4 include alkyl groups ( ^-R13 ), alkenyl groups in which at least one carbon-carbon single bond of the alkyl group ( ^-R13 ) is replaced with a carbon-carbon double bond, and alkoxy groups ( ^-OR13 ) and alkylthio groups ( ^-SR13 ) bonded at the ortho or para position relative to the position of the aromatic ring to which the methine carbon atom to which the hydroxyl group is bonded is bonded.

R ¹³ is preferably an alkyl group having 1 or more carbon atoms. Specific examples of the alkyl group having 1 or more carbon atoms include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, and n-decyl groups; branched alkyl groups such as isopropyl, isobutyl, tert-butyl, isopentyl, tert-pentyl, and 2-ethylhexyl groups; cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantan-1-yl, and adamantane-2-yl groups; Preferred examples of R 13 include alicyclic alkyl groups such as norbornan-1-yl, norbornan-2-yl, and the like; silyl-substituted alkyl groups in which one of the hydrogen atoms in these groups is substituted with a trialkylsilyl group such as a trimethylsilyl group, a triethylsilyl group, and a dimethylethylsilyl group; and alkyl groups in which at least one hydrogen atom on a carbon atom that is not directly bonded to the aromatic ring in compound (I) or (II) is substituted with a cyano group, a fluoro group, or the like. Preferably, R ¹³ has 4 or less carbon atoms.

Examples of the electron-withdrawing group for R ² , R ³ and R ⁴ include —C(═O)R ^13a (R ^13a is a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms which may have a substituent); —C(═O)R ^13b (R ^13b is an aryl group having 6 to 14 carbon atoms which may have a substituent); —C(═O)OR ^13a ; —SO ₂ R ^13a ; —SO ₂ R ^13b ; a nitro group; a nitroso group, a trifluoromethyl group, —OR 13a substituted at the meta position relative to a hydroxyl group; —OR ^13b substituted at the meta position relative to a hydroxyl group; —SR ^13a substituted at the meta position relative to a hydroxyl group; ^{—SR 13b substituted} at the meta position relative to a hydroxyl group; and the above-mentioned —C(═O)R ^13a and —C(═O)OR ^13a , a group in which at least one of the carbon-carbon single bonds in —SO ₂ R ^13a and —SR ^13a is replaced with a carbon-carbon double bond or a group in which at least one of the carbon-carbon single bonds is replaced with a carbon-carbon triple bond; and the like.
Examples of the substituent that R ^13a and R ^13b may have include the same as the first substituent that Sp has.

Specific examples of compounds represented by the above general formula (I) or (II) include those shown below.

One embodiment of the polymer of the present invention is a polymer in which any of the compounds represented by the general formula (I) or (II) is contained in the polymer as unit B, which is bonded to the * moiety in formula (2) at any position of the compound. In this case, the position bonding to the * moiety in formula (2) is preferably any of ^R2 , ^R3 , and ^R4 . For example, in the case of a compound represented by general formula (I), it is preferable that one H in ^R2 is replaced with a bond bonding to the * moiety in formula (2).

As the unit B, preferred examples include those in which R ¹ in the above formula (2) is a hydrogen atom or a linear alkyl group, and L is a carbonyloxy group, a carbonylamino group, or a phenylenediyl group.
Furthermore, as the unit B, a unit in which L is a carbonyloxy group or a carbonylamino group, Sp is a direct bond, and R ¹ is a methyl group, and the methyl group has at least one of an alkyl group having 1 to 4 carbon atoms, a halogen atom, and an aryl group among the first substituents, is preferred from the viewpoint of LWR. Particularly preferred examples of R ¹ having the first substituent include an ethyl group, an isopropyl group, a butyl group, a halogenated methyl group (e.g., a fluoromethyl group, a chloromethyl group, a bromomethyl group, an iodomethyl group), and a benzyl group.
The polymer according to one embodiment of the present invention may have two or more types of the unit B in the polymer.

(Unit C)
The unit C is a unit having a radical-generating structure containing at least one multiple bond selected from the group consisting of a multiple bond between carbon atoms and a multiple bond between a carbon atom and a heteroatom, and is not particularly limited as long as it generates a second radical when at least a part of the polymer is irradiated with a particle beam or electromagnetic wave.
An intramolecular crosslinking reaction can occur between the unit A and the unit C by irradiation with particle beams, electromagnetic waves, or the like.
The multiple bond in the unit C is not particularly limited as long as it generates a radical cation under the influence of particle beams or electromagnetic waves and the radical cation decomposes into a second radical and a cation, but it is preferably not one contained in a benzene-based aromatic and at least one of the bonds shown below. Benzene-based aromatics include not only benzene but also aromatics having a benzene skeleton such as naphthalene and azulene. "Not a multiple bond contained in a benzene-based aromatic" means that it is not a multiple bond contained in these aromatics.

Specific examples of the radical-generating structure containing the multiple bond include units having any one selected from the group consisting of an alkylphenone skeleton, an acyloxime skeleton, and a benzil ketal. These skeletons may have any substituent, and examples of units having an alkylphenone skeleton include an α-aminoacetophenone skeleton. More specifically, preferred examples include those represented by at least one of the following general formulas (4):

In the general formula (4), R ¹ , L and Sp are the same as L and Sp in the general formula (1).
Each R ⁷ is independently any one selected from the group consisting of a hydrogen atom, a hydroxy group, -R ^a (R ^a is a linear, branched, or cyclic alkyl group of 1 to 12 carbon atoms which may have a substituent), -OR ^a , and a group in which at least one carbon-carbon single bond in R ^a is replaced with a carbon-carbon double bond, and -R ^b (R ^b is an aryl group of 6 to 14 carbon atoms which may have a substituent). Two or more R ³ may form a ring structure directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen atom-containing group, and a methylene group.
Examples of R ^a include the same alkyl groups as those of R ^{13 a} , and examples of R ^b include the same aryl groups as those of R ^{13 b} .

Examples of the substituents that R ^a and R ^b may have include the same as those that Sp may have.
However, in the above formula (4), it is preferable that three of ^R7 are not hydrogen atoms. Also, in the above formula (4), it is preferable that at least one of the three ^R7 is OH. By having OH as the above unit C, a crosslinking reaction can also occur between unit B and unit C.

R ⁸ is -R ^a ;-R ^b ;-OR ^a ;-SR ^a ;-OR ^b ;-SR ^b ;-OC(=O)R ^a ;-OC(=O)R ^b ;-C(=O)OR ^a ;-C(=O)OR ^b ;-OC(=O)OR ^a ;-OC(=O)OR ^b ;-NHC(=O)R ^a ;-NR ^a C(=O)R ^a ;-NHC(=O)R ^b ;-NR ^b C(=O)R ^b ;-NR ^a C(=O)R ^b ;-NR ^b C(=O)R ^a ;-N(R ^a ) ₂ ;-N(R ^b ) ₂ ;-N(R ^a )(R ^b _a group in _which at ^least one ^{carbon -} carbon single ^{bond in -R a is} _replaced with a carbon-carbon double bond; and a nitro group _.
In the above formula (4), when ^m1 is 2 or more, two ^R8s may form a ring structure directly by a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen atom-containing group, and a methylene group.

^m2 is an integer of 1 to 3; when ^m2 is 1, ^m1 is an integer of 0 to 4; when ^m2 is 2, ^m1 is an integer of 0 to 6; and when ^m2 is 3, ^m1 is an integer of 0 to 8.

As the unit C, those in which R ¹ in the above formula (4) is a hydrogen atom or a linear alkyl group, and L is a carbonyloxy group, a carbonylamino group, or a phenylenediyl group are preferred.
Furthermore, as the unit C, a unit in which L is a carbonyloxy group or a carbonylamino group, Sp is a direct bond, and R ¹ is a methyl group, and the methyl group has at least one of an alkyl group having 1 to 4 carbon atoms, a halogen atom, and an aryl group among the above-mentioned first substituents, is preferred from the viewpoint of LWR. Particularly preferred examples of R ¹ having the above-mentioned first substituent include an ethyl group, an isopropyl group, a butyl group, a halogenated methyl group (such as a fluoromethyl group, a chloromethyl group, a bromomethyl group, or an iodomethyl group), and a benzyl group.
The polymer according to one embodiment of the present invention may have two or more types of the unit C in the polymer.

(Unit D)
In one embodiment of the present invention, the polymer preferably further contains a unit having an aryloxy group (hereinafter also referred to as "unit D") in addition to the above units A to C. As the unit D, a unit in which a phenol structure is bonded to the * moiety in the above formula (2) at any position of the phenol structure is preferred.
There are no particular limitations on the unit D as long as it can improve the efficiency of generating the acid generated by the unit A. Specific examples include the units shown below.

In the above general formula, each R ¹¹ is preferably independently any one selected from the group consisting of a hydrogen atom and an alkyl group, and the alkyl group represented by R ¹¹ may have a substituent.
Examples of the alkyl group include linear or branched alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, isopropyl, n-isopropyl, sec-butyl, tert-butyl, n-butyl, and pentyl groups.
Examples of the substituent that the alkyl group may have include a hydroxy group, a sulfonyloxy group, an alkylcarbonyloxy group, an alkyloxycarbonyl group, a cyano group, a methoxy group, and an ethoxy group.
Examples of the substituent that R ¹¹ may have include the same as the first substituent that Sp may have.
In the above formula, when two or more R ^11s are not hydrogen atoms, the two R ^11s that are not hydrogen ^atoms may form a ring structure directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen atom-containing group, and a methylene group.
ⁿ⁸ is 4.

Specific examples of unit D include those composed of a monomer such as 4-hydroxyphenyl (meth)acrylate.
When the polymer contains the unit D, it becomes possible to improve the efficiency of acid generation.

As the unit D, there is preferably mentioned one in which in the above formula (2), R ¹ is a hydrogen atom or a linear alkyl group, and L is a carbonyloxy group or a phenylenediyl group.
Furthermore, as the unit D, a unit in which L is a carbonyloxy group or a carbonylamino group, Sp is a direct bond, and R ¹ is a methyl group, and the methyl group has at least one of an alkyl group having 1 to 4 carbon atoms, a halogen atom, and an aryl group among the above-mentioned first substituents, is preferred from the viewpoint of LWR. Particularly preferred examples of R ¹ having the above-mentioned first substituent include an ethyl group, an isopropyl group, a butyl group, a halogenated methyl group (e.g., a fluoromethyl group, a chloromethyl group, a bromomethyl group, an iodomethyl group), and a benzyl group.
The polymer according to one embodiment of the present invention may have two or more types of the unit D in the polymer.

(Unit E)
In one embodiment of the present invention, the polymer preferably further contains, in addition to the above units A to D, an organometallic compound-containing unit E (hereinafter also referred to as "unit E") having a metal atom selected from the group consisting of Sn, Sb, Ge, Bi, and Te.
The metal atom contained in the unit E is not particularly limited as long as it has high absorption for EUV or electron beams, and may be an atom of Groups 10 to 16 of the periodic table in addition to the above metal atoms.
The unit E is preferably a unit in which an alkyl and aryl tin, alkyl and aryl antimony, alkyl and aryl germane, or alkyl and aryl bismuthine structure is bonded to the * portion of formula (2) at any position of the structure.
Unit E has a high efficiency of generating secondary electrons due to EUV irradiation, and can increase the decomposition efficiency of the above-mentioned units A and B. There are no particular limitations on unit E as long as it contains the above-mentioned metal atom having high EUV absorption, and specific examples include the units shown below.

In the above general formula, each R ^12a is preferably independently any one selected from the group consisting of a hydrogen atom and an alkyl group, and the alkyl group represented by R ^12a may have a substituent.
Examples of the alkyl group include linear or branched alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, isopropyl, n-isopropyl, sec-butyl, tert-butyl, n-butyl, and pentyl groups.
Examples of the substituent that the alkyl group may have include a hydroxy group, a sulfonyloxy group, an alkylcarbonyloxy group, an alkyloxycarbonyl group, a cyano group, a methoxy group, and an ethoxy group.
In the above formula, when two or more R ^12a are not hydrogen atoms, the two R ^12a that are not hydrogen ^atoms may form a ring structure directly by a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen atom-containing group, and a methylene group.
In the above formula, two R ^12b may form a ring structure directly by a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen atom-containing group and a methylene group.
ⁿ⁹ is an integer from 0 to 4.

In the above general formula, R ^12b is any one selected from the group consisting of an optionally substituted linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms; an optionally substituted linear, branched, or cyclic alkenyl group having 1 to 6 carbon atoms; an optionally substituted aryl group having 6 to 14 carbon atoms; an optionally substituted heteroaryl group having 4 to 12 carbon atoms; and a direct bond.
Examples of the linear, branched or cyclic alkyl group of R ^12b include the same alkyl groups as those of R ^2b above.
Examples of the linear, branched or cyclic alkenyl group of R ^12b include the same alkenyl groups as those of R ^2b above.

Examples of the aryl group having 6 to 14 carbon atoms for R ^12b include the same as the aryl group for R ^2b above. Examples of the heteroaryl group having 4 to 12 carbon atoms for R ^12b include the same as the heteroaryl group for R ^2b above.
Two or more R ^12a may form a ring structure directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen atom-containing group, and a methylene group. Also, any two of three R ^12b may be bonded to each other to form a ring structure together with the metal atom to which they are bonded.
Examples of the substituent that R ^12a and R ^12b may have include the same as the first substituent that Sp has.

Specific examples of unit E include units constituted from monomers such as 4-vinylphenyl-triphenyltin, 4-vinylphenyl-tributyltin, 4-isopropenylphenyl-triphenyltin, 4-isopropenylphenyl-trimethyltin, trimethyltin acrylate, tributyltin acrylate, triphenyltin acrylate, trimethyltin methacrylate, tributyltin methacrylate, triphenyltin methacrylate, 4-vinylphenyl-diphenylantimony, 4-isopropenylphenyl-diphenylantimony, 4-vinylphenyl-triphenylgermane, 4-vinylphenyl-tributylgermane, 4-isopropenylphenyl-triphenylgermane, and 4-isopropenylphenyl-trimethylgermane.
When the polymer contains the unit E, it becomes possible to improve the efficiency of generating secondary electrons when irradiated with particle beams or electromagnetic waves.

As the unit E, there is preferably mentioned one in which in the above formula (2), R ¹ is a hydrogen atom or a linear alkyl group, and L is a carbonyloxy group or a phenylenediyl group.
Furthermore, as the unit E, a unit in which L is a carbonyloxy group or a carbonylamino group, Sp is a direct bond, and R ¹ is a methyl group, and the methyl group has at least one of an alkyl group having 1 to 4 carbon atoms, a halogen atom, and an aryl group among the above-mentioned first substituents, is preferred from the viewpoint of LWR. Particularly preferred as R ¹ having the above-mentioned first substituent are an ethyl group, an isopropyl group, a butyl group, a halogenated methyl group (e.g., a fluoromethyl group, a chloromethyl group, a bromomethyl group, an iodomethyl group), a benzyl group, etc.
The polymer according to one embodiment of the present invention may have two or more types of the unit E in the polymer.

(Unit F)
In one embodiment of the present invention, the polymer preferably further comprises a unit F having a halogen atom and represented by the following formula (7):

In the general formula (7), R ¹ , L and Sp are preferably selected from the same options as R ¹ , L and Sp in the general formula (2), respectively.
^Rh is any one selected from the group consisting of an optionally substituted linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms; an optionally substituted linear, branched, or cyclic alkyleneoxy group having 1 to 12 carbon atoms; an optionally substituted linear, branched, or cyclic alkenyl group having 1 to 12 carbon atoms; an optionally substituted linear, branched, or cyclic alkenyleneoxy group having 1 to 12 carbon atoms; an optionally substituted aryl group having 6 to 14 carbon atoms; and an optionally substituted heteroaryl group having 4 to 12 carbon atoms; and wherein some or all of the hydrogen atoms substituted on the carbon atoms are substituted with fluorine atoms or iodine atoms.
Examples of the alkyl group, alkenyl group, alkylene group of the alkyleneoxy group, alkenylene group of the alkenyleneoxy group, aryl group, and heteroaryl group of ^Rh are the same as those of Sp.
The substituents for these groups may be the same as those for Sp.

Specific examples of unit F include units obtained from the monomers shown below.

As the unit F, those represented by the formula (7) above in which R ¹ is a hydrogen atom or a linear alkyl group, and L is a carbonyloxy group, a carbonylamino group, or a phenylenediyl group are preferred.
Furthermore, as the unit F, a unit in which L is a carbonyloxy group or a carbonylamino group, Sp is a direct bond, and R ¹ is a methyl group, and the methyl group has at least one of an alkyl group having 1 to 4 carbon atoms, a halogen atom, and an aryl group among the above-mentioned first substituents, is preferred from the viewpoint of LWR. Particularly preferred examples of R ¹ having the above-mentioned first substituent include an ethyl group, an isopropyl group, a butyl group, a halogenated methyl group (such as a fluoromethyl group, a chloromethyl group, a bromomethyl group, or an iodomethyl group), and a benzyl group.
The polymer according to one embodiment of the present invention may have two or more types of the unit F in the polymer.

(Other units)
In one embodiment of the present invention, the polymer may contain, in addition to the above units A to F, units that are commonly used in resist compositions, as long as the effects of the present invention are not impaired.
For example, a unit (hereinafter also referred to as "unit G") having a skeleton containing an ether group, a lactone skeleton, an ester group, a hydroxy group, an epoxy group, a glycidyl group, an oxetanyl group, or the like at the * portion of formula (2) above may be mentioned.
Further, there is mentioned a unit (hereinafter also referred to as "unit H") having a skeleton containing an alcoholic hydroxy group at the position * in the above formula (2). The unit H is different from the above units A to G. The inclusion of the unit H in the above polymer is preferred because it tends to increase the rate of intramolecular crosslinking reactions.
A unit having a skeleton containing an epoxy group, a glycidyl group, an oxetanyl group, or the like is preferred because cationic polymerization can occur when a strong acid is generated from the unit A.

In one embodiment of the present invention, the polymer may have unit I represented by the following general formula (8). Unit I is a unit different from units A to H described above. In one embodiment of the present invention, the polymer has unit I, which makes it easier for the polymer main chain to be cleaved by the action of radicals generated by irradiation with particle beams or electromagnetic waves, thereby shortening the polymer chain at the exposure boundary and reducing the LWR.

In the above general formula (8), each substituent is preferably as follows.
R ¹⁰ is any one selected from the group consisting of a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms; and a linear, branched or cyclic alkenyl group having 1 to 6 carbon atoms; at least one hydrogen atom in the alkyl group and alkenyl group in R ¹⁰ may be substituted with a substituent, L ¹⁰ is a direct bond, and R ^c is an aryl group having 6 to 12 carbon atoms which may have the first substituent. The alkyl group having 1 to 6 carbon atoms and the alkenyl group having 1 to 6 carbon atoms of R ¹⁰ are selected from the same options as the alkyl group having 1 to 6 carbon atoms and the alkenyl group having 1 to 6 carbon atoms of R ¹ above.
Alternatively, R ¹⁰ is a methyl group, and the methyl group has at least one of an alkyl group having 1 to 4 carbon atoms, a halogen atom, and an aryl group among the first substituents; L is a carbonyloxy group or a carbonylamino group; and R ^c is a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms which may have the first substituent.
Alternatively, L is a carbonyloxy group or a carbonylamino group, ^Rc is a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, and ^R10 is a methyl group, which methyl group has at least one of the first substituents, an alkyl group having 1 to 4 carbon atoms, a halogen atom, and an aryl group. Particularly preferred examples of ^R10 having the first substituent include an ethyl group, an isopropyl group, a butyl group, a halogenated methyl group (such as a fluoromethyl group, a chloromethyl group, a bromomethyl group, or an iodomethyl group), and a benzyl group.
The above unit I is a different unit from the above units A to H.

Examples of the unit I include units derived from monomers such as α-methylstyrene derivatives, 2-ethylacrylic acid and ester derivatives thereof, 2-benzylacrylic acid and ester derivatives thereof, 2-propylacrylic acid and ester derivatives thereof, 2-isopropylacrylic acid and ester derivatives thereof, 2-butylacrylic acid and ester derivatives thereof, 2-sec-butylacrylic acid and ester derivatives thereof, 2-fluoromethylacrylic acid and ester derivatives thereof, 2-chloromethylacrylic acid and ester derivatives thereof, 2-bromomethylacrylic acid and ester derivatives thereof, and 2-iodomethylacrylic acid and ester derivatives thereof.
Specific examples of the unit I include those derived from the monomers shown below.

In one embodiment of the present invention, the polymer may have a unit J represented by the following general formula (9):

In the above formula (9), R ¹ , L and Sp are selected from the same options as R ¹ , L and Sp in the above general formula (2), respectively.
^Rd is selected from the group consisting of an optionally substituted linear, branched, or cyclic alkylsilyl group having 1 to 12 carbon atoms, an optionally substituted linear, branched, or cyclic alkyloxysilyl group having 1 to 12 carbon atoms, an optionally substituted linear, branched, or cyclic alkenylsilyl group having 1 to 12 carbon atoms, and an optionally substituted linear, branched, or cyclic alkenyloxysilyl group having 1 to 12 carbon atoms. Some of the carbon atoms may be substituted with silicon atoms and oxygen atoms, thereby forming a siloxane bond in which the bonding hydrogen or carbon is replaced with oxygen.
The unit J contains silicon, which can enhance the etching resistance to oxygen plasma.Furthermore, when the polymer has a silane structure as the unit J, the unit B reacts in the presence of an acid catalyst to generate water, which hydrolyzes the unit J to form silanol, which forms a siloxane bond and crosslinks, thereby improving sensitivity and substrate adhesion, which is preferable.
The unit J is a different unit from the units A to I.

Examples of the unit J include 4-trimethylsilylstyrene, 4-trimethoxysilylstyrene, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, 3-(3,5,7,9,11,13,15-heptaisobutylpentacyclic[9,5,1 ^3,9 ,1 ^5,15 ,1 ^7,13 ]octasiloxan-1-yl)propyl methacrylate, 3-acryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 8-acryloxyoctyltrimethoxysilane, 3-(3,5,7,9,11,13,15-heptaisobutylpentacyclic[9,5,1 ^3,9 ,1 ^5,15 ,1 ^7,13 ]octasiloxane-1-yl)propyl methacrylate.

The resist composition according to one embodiment of the present invention is characterized in that an intramolecular crosslinking reaction occurs upon irradiation with particle beams or electromagnetic waves. Therefore, the resist composition may contain a unit K having an onium salt structure other than unit A. Examples of unit K include units in which the anion ^X- in unit A is replaced with the following ^Y- . Here, ^Y- is a monovalent anion having an organic group that does not contain either a hydroxyl group or a sulfanyl group.

Y ⁻ is preferably any one selected from the group consisting of an alkyl sulfate anion, an aryl sulfate anion, an alkyl sulfonate anion, an aryl sulfonate anion, an alkyl carboxylate anion, an aryl carboxylate anion, a tetrafluoroborate anion, a hexafluorophosphonate anion, a dialkylsulfonylimide anion, a trialkylsulfonate methide anion, a tetrakisphenylborate anion, and a hexafluoroantimonate anion.
Y 1 ^- may be any one selected from the group consisting of monovalent metal oxonium anions and hydrogen acid anions containing the same. At least one hydrogen atom of the alkyl group and aryl group in Y 1 ^- may be substituted with a fluorine atom, and Y 1 - may have the first substituent described above (excluding hydroxyl groups). The number of carbon atoms in Y ^{1 -} , including the substituents, is preferably 1 to 6.
Examples of metal oxonium anions include NiO ₂ ^- and SbO ₃ ^- . Alternatively, divalent or trivalent anions such as VO ₄ ^3- , SeO ₃ ^2- , SeO ₄ ^2- , MoO ₄ ^2- , SnO ₃ ^2- , TeO ₃ ^2- , TeO ₄ ^2- , TaO ₃ ^2- and WO ₄ ^2- may be converted to monovalent anions by appropriately adding H ⁺ , a sulfonium ion, an iodonium ion, or a monovalent or divalent metal cation. The monovalent or divalent metal cation may be any conventional one, such as Na + , Sn ²⁺ , or Ni ²⁺ .

When a strong acid (Y- ^is _{CF3SO3- ,} etc.) is used as the acid generated from the unit K ^and an organic solvent aqueous solution is used as the developer, it is preferred that the polymer of the present invention does not contain a unit having an acid-dissociable group as another unit. The reason for this is that when the polymer of the present invention contains a unit having an acid-dissociable group as another unit, the action of the acid generated by decomposition of the unit K tends to increase the solubility of the polymer in an aqueous developer.

The unit K may be used as a photodegradable base (when the unit K is used as a photodegradable base, it is also referred to as "unit K2"). The anion of the unit K2 is preferably any one of ^Y- selected from the group consisting of an alkylcarboxylate anion and an arylcarboxylate anion. These are monovalent anions having an organic group that does not contain either a hydroxyl group or a sulfanyl group, and at least one hydrogen atom of the alkyl group of the alkylcarboxylate anion and the aryl group of the arylcarboxylate anion may be substituted with a fluorine atom. The polymer containing unit K2 has the effect of reducing the LWR, and is therefore effective when high resolution is required.

A polymer according to one embodiment of the present invention may have two or more types of the above unit K in the polymer.

In one embodiment of the present invention, the polymer preferably has, in molar ratios relative to 1 unit A, 0.2 to 5 unit B, 0 to 3 unit C, 0 to 2 unit D, 0 to 2 unit E, 0 to 2 unit F, 0 to 2 unit G, 0 to 2 unit H, 0 to 2 unit I, 0 to 0.5 unit J, 0 to 4 unit K, and 0 to 2 unit K.
When the polymer contains a unit A1 and at least one of a unit A2 and a unit K2 as a photodegradable base, the molar ratio of the total of the unit A2 and the unit K2 to the unit A1 is preferably 0.1 to 1.0, more preferably 0.3 to 0.6.
The polymer according to one embodiment of the present invention can be obtained by polymerizing the monomer components constituting the respective units described above as raw materials by a conventional method so as to achieve the above-mentioned blending ratio. Alternatively, a polymer containing a unit having an onium salt structure (referred to as a "precursor polymer") may be first synthesized, and the anion moiety of the onium salt structure in the precursor polymer may be salt-exchanged to obtain a polymer containing a unit A having the desired anion.
In one embodiment of the present invention, the molecular weight of the polymer is not particularly limited.

<2> Resist Composition A resist composition according to one embodiment of the present invention is characterized by containing the above-described polymer.
In addition to the above polymer, the composition may optionally contain components such as polysubstituted alcohol compounds, organometallic compounds, and organometallic complexes. Each component will be described below.
The blend amount of the above polymer in the resist composition is preferably 70 to 100% by mass based on the total solid content.
(Polysubstituted alcohol compounds)
The resist composition of one embodiment of the present invention may contain only the above-mentioned polymer, but may also contain, in addition to the above-mentioned polymer, other components such as compounds having two or more hydroxyl groups in the molecule, such as ethylene glycol, triethylene glycol, erythritol, arabitol, 1,4-benzenedimethanol, and 2,3,5,6-tetrafluoro-1,4-benzenedimethanol. By including these in the resist composition, the efficiency of the crosslinking reaction can be improved, and the sensitivity to particle beams or electromagnetic waves can be increased.

(Organometallic Compounds and Organometallic Complexes)
The resist composition according to one embodiment of the present invention preferably further contains either an organometallic compound or an organometallic complex.
The metal is preferably at least one selected from the group consisting of Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, I, Xe, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, At, Rn, and Ra, because this allows sensitization of the unit A and the unit B.

Examples of the organometallic compound include tetraaryltin, tetraalkyltin, and bis(alkylphosphine)platinum.
Examples of organometallic complexes include hafnium(IV) acrylate, zirconium(IV) acrylate, bismuth(III) acrylate, bismuth(III) acetate, and tin(II) oxalate.
The amount of the organometallic compound or organometallic complex blended in the resist composition is preferably 0 to 0.5 molar equivalents relative to the unit A.

(Other ingredients)
In any embodiment, the resist composition of one aspect of the present invention may contain other components within a range that does not impair the effects of the present invention. The components that can be added include at least one selected from known additives such as fluorine-containing water-repellent polymers, acid diffusion controllers, organic carboxylic acids, surfactants, fillers, pigments, antistatic agents, flame retardants, light stabilizers, antioxidants, ion scavengers, and organic solvents.
The fluorine-containing water-repellent polymer may be one that is commonly used in immersion lithography processes, and preferably has a fluorine atom content greater than that of the above-mentioned polymer. By doing so, when a resist film is formed using the resist composition, the water-repellent properties of the fluorine-containing water-repellent polymer can cause the fluorine-containing water-repellent polymer to be unevenly distributed on the surface of the resist film.

The acid diffusion controller controls the diffusion of acid generated from the photoacid generator within the resist film, thereby suppressing undesirable chemical reactions in unexposed areas. This further improves the storage stability of the resulting resist composition, further improving its resolution as a resist, and suppressing changes in the line width of the resist pattern due to variations in the exposure time between exposure and development, resulting in a resist composition with excellent process stability.

Examples of the acid diffusion controller include compounds having one nitrogen atom, two nitrogen atoms, or three nitrogen atoms in the same molecule, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, etc. The acid diffusion controller may be used as a monomer constituting a unit of the polymer and may be contained in the polymer.
Alternatively, a photodegradable base that is photosensitive to light upon exposure to generate a weak acid can be used as the acid diffusion controller. Examples of the photodegradable base include onium salt compounds and iodonium salt compounds that decompose upon exposure to light and lose their acid diffusion control properties.

Specific examples of acid diffusion control agents include compounds described in Japanese Patent No. 3577743, JP-A No. 2001-215689, JP-A No. 2001-166476, JP-A No. 2008-102383, JP-A No. 2010-243773, JP-A No. 2011-37835, and JP-A No. 2012-173505.

The content of the acid diffusion controller is preferably 0.01 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and even more preferably 1 to 10 parts by mass, per 100 parts by mass of the polymer component.
The surfactant is preferably used to improve the coating property. Examples of the surfactant include nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene polyoxypropylene block copolymers, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters, fluorine-containing surfactants, and organosiloxane polymers.
The content of the surfactant is preferably 0.0001 to 12 parts by mass, and more preferably 0.0005 to 1% by mass, per 100 parts by mass of the polymer component.

Preferred organic solvents include, for example, ethylene glycol monoethyl ether acetate, cyclohexanone, 2-heptanone, propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl β-methoxyisobutyrate, ethyl butyrate, propyl butyrate, methyl isobutyl ketone, ethyl acetate, isoamyl acetate, ethyl lactate, toluene, xylene, cyclohexyl acetate, diacetone alcohol, N-methylpyrrolidone, N,N-dimethylformamide, γ-butyrolactone, N,N-dimethylacetamide, propylene carbonate, and ethylene carbonate. These organic solvents may be used alone or in combination.

<3> Method for Preparing Resist Composition There are no particular restrictions on the method for preparing the resist composition of this embodiment of the present invention, and it can be prepared by any known method, such as mixing, dissolving, or kneading the above-mentioned polymer and other optional components.
The polymer can be synthesized by appropriately polymerizing the monomers constituting the units A and B and, if necessary, the monomers constituting other units, by a conventional method. However, the method for producing the polymer according to the present invention is not limited to this.

The resist composition components are preferably dissolved in the above organic solvent at a solids concentration of 1 to 40% by mass. More preferably, it is 1 to 30% by mass, and even more preferably, it is 3 to 20% by mass. By maintaining a solids concentration within this range, the above film thickness can be achieved.

A composition according to one embodiment of the present invention can be obtained by mixing the components of the above composition, and the mixing method is not particularly limited.

<4> Manufacturing Method of Member [0033] One aspect of the present invention is a manufacturing method of a member, including: a resist film formation step of forming a resist film on a substrate using the resist composition; a photolithography step of exposing the resist film in a pattern using particle beams or electromagnetic waves; and a pattern formation step of developing the exposed resist film to obtain a photoresist pattern.
Examples of the member include a device and a mask.

The particle beam or electromagnetic wave used for exposure in the photolithography process includes an electron beam and EUV, respectively.
The amount of light irradiation varies depending on the types and blending ratios of the components in the photocurable composition, the thickness of the coating film, etc., but is preferably 1 J/cm ² or less or 1000 μC/cm ² or less.
When the resist composition contains a sensitizing unit (unit C) in the polymer or a sensitizing compound, it is also preferable to carry out a second exposure with ultraviolet light or the like after irradiation with particle beams or electromagnetic waves.

Furthermore, one aspect of the present invention is a device manufacturing method that includes, in the photolithography process, a step of irradiating a second active energy ray having lower energy than the particle beam or electromagnetic wave after exposure to the particle beam or electromagnetic wave.

The first and second active energy rays are not particularly limited as long as the onium salt of the polymer according to some embodiments of the present invention does not significantly absorb the second active energy ray, but it is preferable that the wavelength of the first active energy ray is shorter than that of the second active energy ray, or that the energy of the photon or particle beam is higher. Examples of each active energy ray are shown below, but are not limited thereto as long as the wavelength of the first active energy ray is shorter than that of the second active energy ray, or the energy of the photon or particle beam is higher.
The first active energy ray is not particularly limited as long as it can generate active species such as an acid in the resist film after irradiation of the resist film. Preferred examples of the first active energy ray include KrF excimer laser light, ArF excimer laser light, electron beams, and extreme ultraviolet (EUV) rays.

The second actinic energy ray may be any light capable of activating a ketone derivative produced by deprotection of the (thio)acetal moiety of the onium salt according to some embodiments of the polymer of the present invention using an acid generated in the resist film after irradiation with the first actinic energy ray, thereby generating an active species such as an acid. Examples of the second actinic energy ray include KrF excimer laser light, UV light, and visible light, and it is particularly preferable to use UV light in the 365 nm (i-line) to 436 nm (g-line) region.

In one embodiment of the device manufacturing method of the present invention, it is preferable to include a heating step using an electric heating wire or laser between the step of irradiating the first active energy ray and the step of irradiating the second active energy ray. Including this step can improve the decomposition efficiency of the onium salt of unit A, leading to further improvement in sensitivity. The heating step can be performed using a hot plate or the like, and in the device manufacturing method, this step corresponds to pre-baking.

Preferably, the method for manufacturing a member according to one embodiment of the present invention further includes the steps of applying a reversal pattern composition so as to cover at least the recesses of the photoresist pattern, etching the resulting coating to expose the surface of the photoresist pattern, and removing the resist film from the exposed surface portion of the resist pattern to obtain a reversal pattern.
As the composition for forming a reverse pattern, a known composition for forming a reverse pattern can be used, and examples thereof include a composition containing a siloxane polymer described in International Publication WO2015/025665.

Another aspect of the present invention is a resist film forming step of forming a resist film on a substrate using the resist composition.
a photolithography step of exposing the resist film to particle beams or electromagnetic waves;
and a pattern forming step of developing the exposed resist film to obtain a photoresist pattern.

Another aspect of the present invention is a resist film forming step of forming a resist film on a substrate using the resist composition.
a photolithography step of exposing the resist film to particle beams or electromagnetic waves;
a pattern formation step of developing the exposed resist film to obtain a photoresist pattern;
a step of applying a reversal pattern composition so as to cover at least the recesses of the photoresist pattern, and etching the resulting coating to expose the surface of the photoresist pattern;
and removing the resist film from the exposed surface portion of the resist pattern to obtain a reverse pattern.
Apart from using the above resist composition, a normal method for forming a reverse pattern may be used.
Preferred examples of the substrate include inorganic substrates such as Si, _SiO2 , SiN, SiON, TiN, WSi, and BPSG (Boron Phosphorus Silicon Glass); for example, coated inorganic substrates such as SOG (Spin on Glass) to which an organic anti-reflective film or the like is applied are used in the device manufacturing method.
In the case of a method for manufacturing a mask, the substrate is preferably an inorganic substrate such as Cr, CrO, CrON, _MoSi2 , or _SiO2 , and more preferably has an EUV absorbing layer such as TaO on the inorganic substrate. The substrate for manufacturing the mask may have the same configuration as the substrate used for a normal mask, and for example, in the case of a transmission mask, it is preferably transparent to the transmitted light of the target, and in the case of a reflective mask, it is preferably high reflectivity for the target light (electromagnetic waves such as EUV).

For development in the pattern forming step, a conventional developer can be used, and examples of the developer include an alkaline developer, a neutral developer, and an organic solvent developer.
In addition to the above, a water-soluble developer containing a water-soluble organic solvent is also preferably used. Examples of the water-soluble organic solvent include organic compounds having one or more carbon atoms that are miscible with water in any ratio, such as methanol, ethanol, isopropyl alcohol, diacetone alcohol, ethylene glycol, ethylene glycol monomethyl ether, propylene glycol, propylene glycol monomethyl ether, triethylene glycol, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, diglyme, triglyme, acetonitrile, acetone, N,N-dimethylformamide, dimethyl sulfoxide, formic acid, acetic acid, and propionic acid.

The water-soluble developer may contain one or more water-soluble organic solvents to form an aqueous solution, and may further contain a non-water-soluble organic solvent. Examples of the non-water-soluble organic solvent include water-immiscible alcohols, water-immiscible ethers, water-immiscible nitriles, water-immiscible ketones, water-immiscible esters such as ethyl acetate, and organic halogen compounds such as methylene chloride.

The substrate is not particularly limited and may be any known substrate, such as a substrate made of a metal such as silicon, silicon nitride, titanium, tantalum, palladium, copper, chromium, or aluminum; a glass substrate; or the like.
In one embodiment of the present invention, preferred examples of active energy rays used for exposure in a photolithography process used to obtain an interlayer insulating film or the like for producing an LSI include UV, KrF excimer laser light, ArF excimer laser light, electron beams, and extreme ultraviolet (EUV) light.

The exposure dose of the first actinic energy ray varies depending on the types and blending ratios of the components in the photocurable composition, the thickness of the coating film, etc., but is preferably 1 J/cm ² or less or 1000 μC/cm ² or less.
In one embodiment of the present invention, the resist film formed from the resist composition preferably has a thickness of 10 to 200 nm. The resist composition is applied to a substrate by a suitable application method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, and then prebaked at 60 to 150°C for 1 to 20 minutes, preferably 80 to 120°C for 1 to 10 minutes, to form a thin film. The thickness of this applied film is 5 to 200 nm, and preferably 10 to 100 nm.

The following examples further illustrate some aspects of the present invention, but the present invention is not limited to these examples.

<Synthesis of Compound A1 Constituting Unit A>
(Synthesis Example 1) Synthesis of dibenzothiophene-9-oxide

7.0 g of dibenzothiophene is dissolved in 21.0 g of formic acid and the temperature is adjusted to 35°C. 4.1 g of 35% by mass hydrogen peroxide is added dropwise and the mixture is stirred at 25°C for 5 hours. After cooling, the reaction solution is added dropwise to 50 g of pure water to precipitate a solid. The precipitated solid is filtered, washed twice with 20 g of pure water, and then recrystallized using acetone. This is filtered and dried to obtain 7.6 g of dibenzothiophene-9-oxide.

(Synthesis Example 2) Synthesis of 9-(4-hydroxyphenyl)dibenzothiophenium iodide

4.0 g of dibenzothiophene-9-oxide obtained in Synthesis Example 1 above and 2.8 g of phenol are dissolved in 16 g of methanesulfonic acid and the temperature is adjusted to 25°C. 1.5 g of diphosphorus pentoxide is added and the mixture is stirred at room temperature for 15 hours. 60 g of purified water is then added and the mixture is stirred for an additional 5 minutes, after which the mixture is washed twice with 20 g of ethyl acetate. The mixture is separated, and 3.6 g of potassium iodide and 30 g of methylene chloride are added to the resulting aqueous layer and the mixture is stirred at room temperature for 2 hours. The mixture is then separated, and the resulting organic layer is washed four times with 40 g of purified water. The recovered organic layer is concentrated and added dropwise to 100 g of diisopropyl ether to precipitate a solid. The precipitated solid is filtered and dried to obtain 6.6 g of 9-(4-hydroxyphenyl)dibenzothiophenium iodide.

(Synthesis Example 3) Synthesis of 9-(4-hydroxyphenyl)dibenzothiophenium methyl sulfate

6.0 g of 9-(4-hydroxyphenyl)dibenzothiophenium iodide obtained in Synthesis Example 2 above and 2.3 g of dimethyl sulfate are dissolved in 15 g of methanol, brought to 25°C, and stirred at room temperature for 4 hours. 45 g of ethyl acetate is then added to precipitate a solid. The precipitated solid is filtered and dried to obtain 4.9 g of 9-(4-hydroxyphenyl)dibenzothiophenium methyl sulfate.

(Synthesis Example 4) Synthesis of 9-(4-methacryloxyphenyl)dibenzothiophenium methyl sulfate (compound a1)

4.0 g of 9-(4-hydroxyphenyl)dibenzothiophenium methyl sulfate obtained in Synthesis Example 3 above and 1.9 g of methacrylic acid chloride are dissolved in 25 g of methylene chloride and the temperature is adjusted to 25°C. A solution of 1.4 g of triethylamine dissolved in 7 g of methylene chloride is added dropwise to the solution and stirred at 25°C for 2 hours. After stirring, 20 g of pure water is added and stirred for an additional 10 minutes before separating the layers. The organic layer is washed twice with 20 g of pure water, and the recovered organic layer is concentrated and added dropwise to 60 g of diisopropyl ether to precipitate a solid. The precipitated solid is filtered and dried to obtain 3.0 g of 9-(4-methacryloxyphenyl)dibenzothiophenium methyl sulfate (compound a1).

(Synthesis Example 5) Synthesis of 9-(4-methacryloxyphenyl)dibenzothiophenium-1,1-difluoro-2-hydroxyethylsulfonate (Compound A1)

4.0 g of 9-(4-methacryloxyphenyl)dibenzothiophenium methyl sulfate obtained in Synthesis Example 4 above and 3.2 g of sodium 1,1-difluoro-2-hydroxyethanesulfonate are added to 25 g of methylene chloride and 20 g of pure water and stirred at 25°C for 1 hour. After stirring, the mixture is separated, and 1.6 g of sodium 1,1-difluoro-2-hydroxysulfonate and 20 g of pure water are added again and stirred at 25°C for 30 minutes. After stirring, the mixture is separated and the recovered organic layer is concentrated. The solvent is removed from the resulting organic layer and then purified by column chromatography (methylene chloride/methanol = 90/10 (volume ratio)) to obtain 3.0 g of 9-(4-methacryloxyphenyl)dibenzothiophenium-1,1-difluoro-2-hydroxyethylsulfonate (Compound A1).

<Synthesis of Compound A2 Constituting Unit A>
(Synthesis Example 6) Synthesis of (4-hydroxy)phenyldiphenylsulfonium iodide

By performing the same procedure as in Synthesis Example 2 above, except using diphenyl sulfoxide instead of dibenzothiophene-9-oxide, 5.9 g of (4-hydroxy)phenyldiphenylsulfonium iodide is obtained.

(Synthesis Example 7) Synthesis of (4-methacryloxy)phenyldiphenylsulfonium trifluoromethanesulfonate (compound a2)

By carrying out the same procedure as in Synthesis Example 4 above, except using (4-hydroxy)phenyldiphenylsulfonium-methylsulfate instead of 9-(4-hydroxyphenyl)dibenzothiophenium-methylsulfate and using silica gel column chromatography (methylene chloride/methanol = 9/1) instead of diisopropyl ether to precipitate the solid, 3.8 g of 9-(4-methacryloxyphenyl)dibenzothiophenium-methylsulfate (compound a2) is obtained.

(Synthesis Example 8) Synthesis of 9-(4-methacryloxyphenyl)diphenylsulfonium-1,1-difluoro-2-hydroxyethylsulfonate (Compound A2)

By carrying out the same procedure as in Synthesis Example 5 above, except using (4-methacryloxy)phenyldiphenylsulfonium-methylsulfate instead of 9-(4-methacryloxyphenyl)dibenzothiophenium-methylsulfate, 3.0 g of 9-(4-methacryloxyphenyl)diphenylsulfonium-1,1,difluoro-2-hydroxyethylsulfonate (Compound A2) is obtained.

<Synthesis of Compound A3 Constituting Unit A>
Synthesis Example 9: Synthesis of 9-(4-methacryloxyphenyl)diphenylsulfonium-1,1,2-trifluoro-3-hydroxypropylsulfonate (Compound A3)

By carrying out the same procedure as in Synthesis Example 5 above, except for using (4-methacryloxy)phenyldiphenylsulfonium-methylsulfate instead of 9-(4-methacryloxyphenyl)dibenzothiophenium-methylsulfate and using sodium 1,1,2-trifluoro-2-hydroxypropanesulfonate instead of sodium 1,1-difluoro-2-hydroxyethanesulfonate, 3.0 g of 9-(4-methacryloxyphenyl)diphenylsulfonium-1,1,2-trifluoro-3-hydroxypropylsulfonate (Compound A3) is obtained.

<Synthesis of Compound A4 Constituting Unit A>
Synthesis Example 10: Synthesis of 9-(4-methacryloxyphenyl)diphenylsulfonium-3-allyloxy-2-hydroxypropylsulfonate (Compound A4)

By carrying out the same procedure as in Synthesis Example 5 above, except for using (4-methacryloxy)phenyldiphenylsulfonium-methylsulfate instead of 9-(4-methacryloxyphenyl)dibenzothiophenium-methylsulfate and using sodium 3-allyloxy-2-hydroxypropanesulfonate instead of sodium 1,1-difluoro-2-hydroxyethanesulfonate, 3.0 g of 9-(4-methacryloxyphenyl)diphenylsulfonium 3-allyloxy-2-hydroxypropylsulfonate (Compound A4) is obtained.

<Synthesis of Compound A5 Constituting Unit A>
Synthesis Example 11: Synthesis of 9-(4-methacryloxyphenyl)diphenylsulfonium-3-mercaptopropylsulfonate (Compound A5)

By carrying out the same procedure as in Synthesis Example 5 above, except for using (4-methacryloxy)phenyldiphenylsulfonium-methylsulfate instead of 9-(4-methacryloxyphenyl)dibenzothiophenium-methylsulfate and using sodium 3-mercaptopropanesulfonate instead of sodium 1,1-difluoro-2-hydroxyethanesulfonate, 3.0 g of 9-(4-methacryloxyphenyl)diphenylsulfonium-3-mercaptopropylsulfonate (Compound A5) is obtained.

<Synthesis of Compound A6 Constituting Unit A>
Synthesis Example 12: Synthesis of 5-(4-hydroxynaphthyl)tetramethylenesulfonium-p-toluenesulfonate

By performing the same procedure as in Synthesis Example 2 above, except using tetramethylene sulfoxide instead of dibenzothiophene-9-oxide, 1-naphthol instead of phenol, and sodium p-toluenesulfonate instead of potassium iodide, 3.5 g of 5-(4-hydroxynaphthyl)tetramethylenesulfonium p-toluenesulfonate is obtained.

(Synthesis Example 13) Synthesis of 5-(4-methacryloxynaphthyl)tetramethylenesulfonium-p-toluenesulfonate

By carrying out the same procedure as in Synthesis Example 4 above, except using 5-(4-hydroxynaphthyl)tetramethylenesulfonium trifluoromethanesulfonate instead of 9-(4-hydroxyphenyl)dibenzothiophenium methylsulfate, 5.1 g of (5-(4-methacryloxynaphthyl)tetramethylenesulfonium p-toluenesulfonate is obtained.

(Synthesis Example 14) Synthesis of 5-(4-methacryloxynaphthyl)tetramethylenesulfonium-1,1-difluoro-2-hydroxyethylsulfonate (Compound A6)

By carrying out the same procedure as in Synthesis Example 5 above, except using (4-methacryloxy)phenyldiphenylsulfonium-methylsulfate instead of 9-(4-methacryloxyphenyl)dibenzothiophenium-methylsulfate, 3.0 g of 9-(4-methacryloxyphenyl)diphenylsulfonium-1,1-difluoro-2-hydroxyethylsulfonate (Compound A6) is obtained.

<Synthesis of Compound A7 Constituting Unit A>
Synthesis Example 15: Synthesis of 2-(4-methoxybenzoyl)dibenzothiophene

Add 5.0 g of aluminum chloride to 50 g of methylene chloride and bring the temperature to 0°C. Add 5 g of dibenzothiophene, then dissolve 4.6 g of 4-methoxybenzoyl chloride in 9.2 g of methylene chloride and add dropwise over 30 minutes. After addition, stir at 25°C for 1 hour, add 60 g of purified water, stir for an additional 5 minutes, and then wash twice with 20 g of toluene. Distill off the resulting organic layer. Purify the resulting residue by recrystallization using 30 g of acetone to obtain 6.1 g of 2-(4-methoxybenzoyl)dibenzothiophene.

(Synthesis Example 16) Synthesis of 2-(4-methoxybenzoyl)dibenzothiophene-5-oxide

6.0 g of 2-(4-methoxybenzoyl)dibenzothiophene obtained in Synthesis Example 15 above was dissolved in 30 g of formic acid, and 3.5 g of 35% by mass hydrogen peroxide solution was added dropwise to the solution while cooling on ice. The mixture was then warmed to room temperature and stirred for 5 hours. After stirring, 80 g of pure water was added dropwise to the reaction solution to precipitate a solid. The precipitated solid was filtered, washed three times with 10 g of pure water, and then dried to obtain crude crystals. The crude crystals were recrystallized using 100 g of acetone and 200 g of ethanol to obtain 4.3 g of 2-(4-methoxybenzoyl)dibenzothiophene-5-oxide.

(Synthesis Example 17) Synthesis of 2-[dimethoxy-(4-methoxyphenyl)methyldibenzothiophene-5-oxide

5.0 g of 2-(4-methoxybenzoyl)dibenzothiophene-5-oxide obtained in Synthesis Example 16 is added to 20 g of methanol, followed by the addition of 5.0 g of trimethyl orthoformate and 20 mg of concentrated sulfuric acid and stirring at 60°C for 3 hours. After stirring, the reaction solution is added to a mixed solution of 60 g of methylene chloride and 10 g of a 3% by mass aqueous solution of sodium bicarbonate, and the mixture is stirred for 10 minutes to recover the organic layer. The resulting organic layer is washed three times with water, and the methylene chloride is then distilled off to obtain 4.6 g of 2-[dimethoxy-(4-methoxyphenyl)methyldibenzothiophene-5-oxide.

(Synthesis Example 18) Synthesis of 4-vinylphenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium-1,1-difluoro-2-hydroxyethanesulfonate (Compound A7)

To a solution of 4.0 g of 2-[dimethoxy-(4-methoxyphenyl)methyldibenzothiophene-5-oxide obtained in Synthesis Example 17 above, 1.1 g of trimethylsilyl chloride, and 1.8 g of triethylamine dissolved in 15.5 g of methylene chloride, 15 ml of a 1.0 mol/L THF solution of 4-vinylphenylmagnesium bromide is added dropwise at 10°C or below, and the mixture is then stirred at 25°C for 1 hour. After stirring, 30 g of a 10% by weight aqueous ammonium chloride solution is added at 5°C or below and the mixture is stirred for an additional 10 minutes, after which 40 g of methylene chloride and 2.7 g of sodium 1,1-difluoro-2-hydroxyethanesulfonate are added and the mixture is stirred at 25°C for approximately 2 hours. The mixture is separated and washed three times with water, after which the methylene chloride is distilled off to obtain crude crystals. The crude crystals are purified by silica gel column chromatography (methylene chloride/methanol=90/10 (volume ratio)) to obtain 2.6 g of 4-vinylphenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium-1,1-difluoro-2-hydroxyethanesulfonate (compound A7).

<Synthesis of Compound A8 Constituting Unit A>
(Synthesis Example 19) Synthesis of 4-hydroxyphenyl-2-[(4-methoxy)benzoyl]dibenzothiophenium iodide

The same procedure as in Synthesis Example 2 was carried out except that 2-(4-methoxybenzoyl)dibenzothiophene-5-oxide was used instead of dibenzothiophene-9-oxide, to obtain 3.0 g of 4-hydroxyphenyl-2-[(4-methoxy)benzoyl]dibenzothiophenium iodide.

(Synthesis Example 20) Synthesis of 4-hydroxyphenyl-2-[(4-methoxy)benzoyl]dibenzothiophenium methyl sulfate

By carrying out the same procedure as in Synthesis Example 3 above, except using 4-hydroxyphenyl-2-[(4-methoxy)benzoyl]dibenzothiophenium-iodide obtained in Synthesis Example 19 above instead of 9-(4-hydroxyphenyl)dibenzothiophenium-iodide, 3.0 g of 4-hydroxyphenyl-2-[(4-methoxy)benzoyl]dibenzothiophenium-methylsulfate is obtained.

(Synthesis Example 21) Synthesis of 4-hydroxyphenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium methyl sulfate

By carrying out the same procedure as in Synthesis Example 17 above, except using 4-hydroxyphenyl-2-[(4-methoxy)benzoyl]dibenzothiophenium-methylsulfate obtained in Synthesis Example 20 above instead of 2-(4-methoxybenzoyl)dibenzothiophene-5-oxide, 3.0 g of 4-hydroxyphenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium-methylsulfate is obtained.

(Synthesis Example 22) Synthesis of 4-methacryloxyphenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium methyl sulfate

By carrying out the same procedure as in Synthesis Example 4 above, except using 4-hydroxyphenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium-methylsulfate obtained in Synthesis Example 21 above instead of 9-(4-methacryloxyphenyl)dibenzothiophenium-methylsulfate, 3.0 g of 4-methacryloxyphenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium-methylsulfate is obtained.

(Synthesis Example 23) Synthesis of 4-methacryloxyphenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium-1,1-difluoro-2-hydroxyethanesulfonate (Compound A8)

By carrying out the same procedure as in Synthesis Example 5 above, except using 4-methacryloxyphenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium-methylsulfate obtained in Synthesis Example 22 above instead of 9-(4-methacryloxyphenyl)dibenzothiophenium-methylsulfate, 3.0 g of 4-methacryloxyphenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium-1,1-difluoro-2-hydroxyethanesulfonate (Compound A8) is obtained.

<Synthesis of Compound A9 Constituting Unit A>
Synthesis Example 24: Synthesis of 2-[methoxyphenyl-[1,3]dioxepan-2-yl]dibenzothiophene-5-oxide

By performing the same procedure as in Synthesis Example 17 above, except using 1,4-butanediol instead of methanol, 3.0 g of 2-[methoxyphenyl-[1,3]dioxepan-2-yl]dibenzothiophene-5-oxide is obtained.

(Synthesis Example 25) Synthesis of 4-vinylphenyl-2-[methoxyphenyl-[1,3]dioxepan-2-yl]dibenzothiophenium-1,1-difluoro-2-hydroxyethanesulfonate (Compound A9)

By carrying out the same procedure as in Synthesis Example 18 above, except using 2-[methoxyphenyl-[1,3]dioxepan-2-yl]dibenzothiophene-5-oxide obtained in Synthesis Example 24 above instead of 2-[dimethoxy-(4-methoxyphenyl)methyldibenzothiophene-5-oxide methanol, 3.0 g of 4-vinylphenyl-2-[methoxyphenyl-[1,3]dioxepan-2-yl]dibenzothiophenium-1,1-difluoro-2-hydroxyethanesulfonate (Compound A9) is obtained.

<Synthesis of Compound A10 Constituting Unit A>
Synthesis Example 26: Synthesis of phenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium bromide

To a solution of 4.0 g of 2-[dimethoxy-(4-methoxyphenyl)methyldibenzothiophene-5-oxide obtained in Synthesis Example 17 above, 1.1 g of trimethylsilyl chloride, and 1.8 g of triethylamine dissolved in 15.5 g of methylene chloride, 15 ml of a 1.0 mol/L THF solution of 4-vinylphenylmagnesium bromide was added dropwise at 10°C or below, followed by stirring at 25°C for 1 hour. After stirring, 30 g of a 10% by weight aqueous ammonium chloride solution was added at 5°C or below, and the mixture was stirred for an additional 10 minutes. 40 g of methylene chloride was then added and the mixture was stirred at 25°C for approximately 2 hours. The mixture was separated and washed three times with water, after which the methylene chloride was distilled off to obtain crude crystals. The crude crystals were purified by silica gel column chromatography (methylene chloride/methanol = 90/10 (volume ratio)) to obtain 3.0 g of phenyl-2-[dimethoxy-(4-methoxyphenyl)methyl]dibenzothiophenium bromide.

(Synthesis Example 27) Synthesis of phenyl-2-(4-hydroxybenzoyl)dibenzothiophenium bromide

3.0 g of phenyl-2-[dimethoxy-(4-methoxyphenyl)]methyldibenzothiophenium bromide obtained in Synthesis Example 26 above is added to 30 ml of acetic acid and heated to 110°C, after which 2.2 g of 48% aqueous hydrobromic acid is added dropwise and stirred for 18 hours. After cooling to 25°C, 60 ml of purified water and 40 g of methylene chloride are added and stirred. The mixture is separated and washed three times with water, after which the methylene chloride is distilled off to obtain crude crystals. The crude crystals are purified by silica gel column chromatography (methylene chloride/methanol = 80/20 (volume ratio)) to obtain 1.4 g of phenyl-2-(4-hydroxybenzoyl)dibenzothiophenium bromide.

(Synthesis Example 28) Synthesis of phenyl-2-[dimethoxy-(4-hydroxyphenyl)]methyldibenzothiophenium bromide

1.5 g of phenyl-2-[dimethoxy-(4-hydroxyphenyl)]methyldibenzothiophenium bromide is obtained by performing the same procedure as in Synthesis Example 17 above, except that phenyl-2-(4-hydroxybenzoyl)dibenzothiophenium bromide obtained in Synthesis Example 27 above is used instead of 2-(4-methoxybenzoyl)dibenzothiophene-5-oxide.

(Synthesis Example 29) Synthesis of phenyl-2-{dimethoxy-[4-(3-methacryloxy)propyloxyphenyl]methyl}dibenzothiophenium-1,1-difluoro-2-hydroxyethanesulfonate (Compound A10)

1.5 g of phenyl-2-[dimethoxy-(4-hydroxyphenyl)]methyldibenzothiophenium bromide obtained in Synthesis Example 28 above and 1.10 g of 3-trifluoromethanesulfonylpropane methacrylate were dissolved in 10 ml of acetonitrile, followed by the addition of 2.1 g of potassium carbonate and stirring at 70°C for 3 hours. 30 ml of methylene chloride, 15 ml of purified water, and 1.3 g of sodium 1,1-difluoro-2-hydroxyethanesulfonate were then added and stirred. The resulting solution was separated and washed three times with water, after which the methylene chloride was distilled off to obtain crude crystals. The crude crystals were purified by silica gel column chromatography (methylene chloride/methanol = 80/20 (volume ratio)) to obtain 1.0 g of phenyl-2-{dimethoxy-[4-(1-ethoxyethyl)oxyphenyl]methyl}dibenzothiophenium nonafluorobutanesulfonate (Compound A10).

<Synthesis of Compound B1 Constituting Unit B>
(Synthesis Example 30) Synthesis of 2,4-dimethoxy-2'-hydroxybenzohydrol

6.0 g of 2,4-dimethoxy-4'-hydroxybenzophenone was dissolved in 32 g of THF, and 2.2 g of lithium aluminum hydride was added. The mixture was stirred at room temperature for 3 hours. 6 g of purified water was then added while checking for hydrogen generation, followed by stirring for an additional 10 minutes. A 5% by mass aqueous solution of sodium oxalate was added, and the mixture was stirred for 10 minutes. 30 g of ethyl acetate was then added and the mixture was separated. The mixture was washed three times with 10 g of water, and the collected organic layer was concentrated to obtain 5.9 g of 2,4-dimethoxy-2'-hydroxybenzohydrol.

(Synthesis Example 31) Synthesis of 2,4-dimethoxy-2'-methacryloxyhydroxybenzohydrol (Compound B1)

4.0 g of 2,4-dimethoxy-2'-hydroxybenzohydrol obtained in Synthesis Example 30 and 4.2 g of methacrylic anhydride are dissolved in 40 g of methylene chloride and the temperature is adjusted to 25°C. A solution of 2.8 g of triethylamine in 7 g of methylene chloride is added dropwise to the mixture and stirred at 25°C for 2 hours. After stirring, 20 g of pure water is added and the mixture is stirred for an additional 10 minutes before being separated into layers. The organic layer is washed twice with 20 g of pure water, and the recovered organic layer is concentrated. The solvent is distilled off from the resulting organic layer, which is then purified by column chromatography (ethyl acetate/hexane = 15/85 (volume ratio)) to obtain 2.6 g of 2,4-dimethoxy-2'-methacryloxyhydroxybenzohydrol (Compound B1).

<Synthesis of Compound B2 Constituting Unit B>
(Synthesis Example 32) Synthesis of 2-hydroxybenzohydrol

By performing the same procedure as in Synthesis Example 30 above, except using 2-hydroxybenzophenone instead of 2,4-dimethoxy-4'-hydroxybenzophenone, 3.5 g of 2-hydroxybenzohydrol is obtained.

(Synthesis Example 33) Synthesis of 2-methacryloxyhydroxybenzohydrol (Compound B2)

3.5 g of 2-methacryloxyhydroxybenzohydrol (compound B2) is obtained by carrying out the same procedure as in Synthesis Example 31 above, except that the 2-hydroxybenzohydrol obtained in Synthesis Example 32 is used instead of 2,4-dimethoxy-2'-hydroxybenzohydrol and the residue obtained after concentration is purified by column chromatography (ethyl acetate/hexane = 10/90 (volume ratio)).

<Synthesis of Compound B3 Constituting Unit B>
(Synthesis Example 34) Synthesis of 1-(4-hydroxyphenyl)ethanol

By performing the same procedure as in Synthesis Example 30 above, except using 4-hydroxyacetophenone instead of 2,4-dimethoxy-4'-hydroxybenzophenone, 2.7 g of 1-(4-hydroxyphenyl)ethanol is obtained.

(Synthesis Example 35) Synthesis of 1-(4-methacryloxyphenyl)ethanol (Compound B3)

3.5 g of 2-methacryloxyhydroxybenzhydrol (compound B3) is obtained by performing the same procedure as in Synthesis Example 31 above, except that the 2-hydroxybenzhydrol obtained in Synthesis Example 34 is used instead of 2,4-dimethoxy-2'-hydroxybenzhydrol and the residue obtained after concentration is purified by column chromatography (ethyl acetate/hexane = 10/90 (volume ratio)).

<Synthesis of Compound B4 Constituting Unit B>
(Synthesis Example 36) Synthesis of 2,4-dimethoxy-4'-(2-vinyloxy)ethoxybenzophenone

4.0 g of 2,4-dimethoxy-4'-hydroxybenzophenone, 4.8 g of 2-chloroethyl vinyl ether, and 6.4 g of potassium carbonate are dissolved in 24 g of dimethylformamide. The mixture is stirred at 110°C for 15 hours. The mixture is then cooled to 25°C, 60 g of water is added, and the mixture is further stirred. After that, it is extracted with 24 g of toluene and washed three times with 10 g of water. The recovered organic layer is concentrated, and the solvent is removed from the resulting organic layer. The organic layer is then purified by column chromatography (ethyl acetate/hexane = 10/90 (volume ratio)) to obtain 5.4 g of 2,4-dimethoxy-4'-(2-vinyloxy)ethoxybenzophenone.

(Synthesis Example 37) Synthesis of 2,4-dimethoxy-4'-(2-hydroxy)ethoxybenzophenone

5.4 g of 2,4-dimethoxy-4'-(2-vinyloxy)ethoxybenzophenone obtained in Synthesis Example 36, 0.42 g of pyridinium-p-toluenesulfonic acid, and 4.2 g of pure water are dissolved in 36 g of acetone. The mixture is stirred at 35°C for 12 hours. After adding a 3% by mass aqueous solution of sodium carbonate, the mixture is further stirred and extracted with 42 g of ethyl acetate. The organic layer is washed three times with 10 g of water and then concentrated to obtain 4.3 g of 2,4-dimethoxy-4'-(2-hydroxy)ethoxybenzophenone.

(Synthesis Example 38) Synthesis of 2,4-dimethoxy-4'-(2-hydroxy)ethoxybenzohydrol

By carrying out the same procedure as in Synthesis Example 30 above, except using 2,4-dimethoxy-4'-(2-hydroxy)ethoxybenzophenone obtained in Synthesis Example 37 instead of 2,4-dimethoxy-2'-hydroxybenzhydrol, 2.7 g of 2,4-dimethoxy-4'-(2-hydroxy)ethoxybenzohydrol is obtained.

(Synthesis Example 39) Synthesis of 2,4-dimethoxy-4'-(2-methacryloxy)ethoxybenzohydrol (Compound B4)

By carrying out the same procedure as in Synthesis Example 31 above, except for using 2,4-dimethoxy-4'-(2-hydroxy)ethoxybenzohydrol obtained in Synthesis Example 38 instead of 2,4-dimethoxy-2'-hydroxybenzhydrol and purifying the residue obtained by concentration by column chromatography (ethyl acetate/hexane = 10/90 (volume ratio)), 3.5 g of 2,4-dimethoxy-4'-(2-methacryloxy)ethoxybenzohydrol (compound B4) is obtained.

<Synthesis of Compound B5 Constituting Unit B>
(Synthesis Example 40) Synthesis of 1-(3-hydroxy-4-methoxyphenyl)methanol

By performing the same procedure as in Synthesis Example 30 above, except using 3-hydroxy-4-methoxybenzaldehyde instead of 2,4-dimethoxy-2'-hydroxybenzhydrol, 2.7 g of 1-(4-hydroxyphenyl)methanol is obtained.

(Synthesis Example 41) Synthesis of 1-(3-methacryloxy-4-methoxyphenyl)methanol (Compound B5)

By carrying out the same procedure as in Synthesis Example 31 above, except that 1-(4-hydroxyphenyl)methanol obtained in Synthesis Example 40 was used instead of 2,4-dimethoxy-2'-hydroxybenzhydrol and the residue obtained after concentration was purified by column chromatography (ethyl acetate/hexane = 10/90 (volume ratio)), 2.1 g of 1-(3-methacryloxy-4-methoxyphenyl)methanol (compound B5) was obtained.

<Synthesis of Compound B6 Constituting Unit B>
(Synthesis Example 42) Synthesis of 4-hydroxy-4'-methoxybenzohydrol

3.5 g of 4-hydroxy-4'-methoxybenzohydrol is obtained by performing the same procedure as in Synthesis Example 30 above, except using 4-hydroxy-4'-methoxybenzophenone instead of 2,4-dimethoxy-4'-hydroxybenzophenone.

(Synthesis Example 43) Synthesis of 4-methacryloxy-4'-methoxybenzohydrol (Compound B6)

By performing the same procedure as in Synthesis Example 31 above, except using 4-hydroxy-4'-methoxybenzohydrol obtained in Synthesis Example 42 instead of 4-hydroxybenzohydrol, 3.5 g of 4-methacryloxy-4'-methoxybenzohydrol (compound B6) is obtained.

<Synthesis of Compound C1 Constituting Unit C>
Synthesis Example 44: Synthesis of 1-[4-(2-methacryloxy)ethoxyphenyl]-2-hydroxy-2-methyl-1-propanone (Compound C1)

4.0 g of 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (Irgacure 2959) and 4.6 g of methacrylic anhydride were dissolved in 40 g of methylene chloride and the temperature was adjusted to 25°C. A solution of 3.0 g of triethylamine in 7 g of methylene chloride was added dropwise to the mixture and stirred at 25°C for 2 hours. After stirring, 20 g of purified water was added and the mixture was stirred for an additional 10 minutes before being separated. The organic layer was washed twice with 20 g of purified water, and the recovered organic layer was concentrated. The solvent was removed by distillation and the resulting organic layer was purified by column chromatography (ethyl acetate/hexane = 10/90 (volume ratio)) to obtain 4.9 g of 1-[4-(2-methacryloxy)ethoxyphenyl]-2-hydroxy-2-methyl-1-propanone (Compound C1).

<Synthesis of Compound C2 Constituting Unit C>
Synthesis Example 45: Synthesis of 1-(4-hydroxyphenyl)-2,2-dimethyl-1-propanone

2.0 g of magnesium and 10 g of THF are added to a flask from which moisture has been removed. A solution of 10.0 g of 4-(2-ethoxy)ethoxyphenyl bromide dissolved in 50.0 g of THF is added dropwise to this solution at room temperature over one hour. After the addition and stirring at room temperature for one hour, the resulting 4-(2-ethoxy)ethoxyphenyl magnesium bromide solution is added dropwise to a flask containing 9.8 g of pivaloyl chloride and 40 g of THF (prepared separately) over 30 minutes at 5°C. After the addition and stirring for 30 minutes, 150 g of 3% by weight hydrochloric acid is added and the mixture is stirred for an additional 10 minutes. The THF is then distilled off and the mixture is extracted with 150 g of ethyl acetate. The mixture is separated, and the resulting organic layer is washed three times with 60 g of pure water. Thereafter, the solvent is distilled off from the organic layer obtained by liquid separation, and the residue is purified by column chromatography (ethyl acetate/hexane=20/80 (volume ratio)) to obtain 5.8 g of 1-(4-hydroxyphenyl)-2,2-dimethyl-1-propanone.

(Synthesis Example 46) Synthesis of 1-(4-methacryloxyphenyl)-2,2-dimethyl-1-propanone (Compound C2)

4.0 g of 1-(4-hydroxyphenyl)-2,2-dimethyl-1-propanone obtained in Synthesis Example 45 above and 4.1 g of methacrylic anhydride are dissolved in 32 g of methylene chloride and the temperature is adjusted to 25°C. A solution of 2.7 g of triethylamine in 7 g of methylene chloride is added dropwise to the mixture and stirred at 25°C for 2 hours. After stirring, 20 g of pure water is added and stirred for an additional 10 minutes before separating the layers. The organic layer is washed twice with 20 g of pure water, and the recovered organic layer is concentrated. The solvent is distilled off from the resulting organic layer, which is then purified by column chromatography (ethyl acetate/hexane = 10/90 (volume ratio)) to obtain 4.6 g of 1-(4-methacryloxyphenyl)-2,2-dimethyl-1-propanone (Compound C2).

<Synthesis of Compound C3 Constituting Unit C>
Synthesis Example 47: Synthesis of 1-(4-acryloxyphenyl)-2,2-dimethyl-1-propanone (Compound C3)

By performing the same procedure as in Synthesis Example 46 above, except using acrylic acid chloride instead of methacrylic acid anhydride, 5.3 g of 1-(4-acryloxyphenyl)-2,2-dimethyl-1-propanone (compound C3) is obtained.

<Synthesis of Compound C4 Constituting Unit C>
(Synthesis Example 48) Synthesis of 1-(6-hydroxynaphthalen-2-yl)-2,2-dimethyl-1-propanone

By performing the same procedure as in Synthesis Example 45 above, except using 2-bromo-6-(2-ethoxy)ethoxynaphthalene instead of 4-(2-ethoxy)ethoxyphenyl bromide, 6.9 g of 1-(6-hydroxynaphthalen-2-yl)-2,2-dimethyl-1-propanone is obtained.

(Synthesis Example 49) Synthesis of 1-(6-methacryloxynaphthalen-2-yl)-2,2-dimethyl-1-propanone (Compound C4)

By performing the same procedure as in Synthesis Example 46 above, except using 1-(6-hydroxynaphthalen-2-yl)-2,2-dimethyl-1-propanone instead of 1-(4-hydroxyphenyl)-2,2-dimethyl-1-propanone, 5.3 g of 1-(6-methacryloxynaphthalen-2-yl)-2,2-dimethyl-1-propanone (compound C4) is obtained.

<Synthesis of Compound C5 Constituting Unit C>
Synthesis Example 50: Synthesis of 1-[4-(2-hydroxyethoxy)phenyl]-2,2-dimethyl-1-propanone

By performing the same procedure as in Synthesis Example 45 above, except using 4-(2-vinyloxy)ethoxyphenyl bromide instead of 4-(2-ethoxy)ethoxyphenyl bromide, 6.3 g of 1-[4-(2-hydroxyethoxy)phenyl]-2,2-dimethyl-1-propanone is obtained.

(Synthesis Example 51) Synthesis of 1-[4-(2-methacryloxy)ethoxyphenyl]-2,2-dimethyl-1-propanone (Compound C5)

By performing the same procedure as in Synthesis Example 46 above, except using 1-(2-hydroxyethoxyphenyl)-2,2-dimethyl-1-propanone instead of 1-(4-hydroxyphenyl)-2,2-dimethyl-1-propanone, 5.6 g of 1-[4-(2-methacryloxy)ethoxyphenyl]-2,2-dimethyl-1-propanone (compound C5) is obtained.

<Synthesis of Compound C6 Constituting Unit C>
(Synthesis Example 52) Synthesis of phenylglyoxylic acid chloride

5.0 g of phenylglyoxylic acid was dissolved in 35 g of anisole and the temperature was raised to 50°C. 5.1 g of oxalyl chloride was added dropwise over 10 minutes and stirred at 50°C for 2 hours. The temperature was then raised to 70°C and excess oxalyl chloride was removed by distillation. After that, the anisole was removed by distillation under reduced pressure and the mixture was concentrated, yielding 26.3 g of an anisole solution of phenylglyoxylic acid chloride.

(Synthesis Example 53) Synthesis of 1-(4-methoxyphenyl)-2-phenylethanedione

25.0 g of the anisole solution of phenylglyoxylic acid chloride obtained in Synthesis Example 52 is dissolved in 35 g of methylene chloride and the temperature is adjusted to 0°C. 4.3 g of aluminum chloride is added and stirred at 0°C for 2 hours. 35 g of purified water is added and stirred for 10 minutes, after which the layers are separated. The resulting organic layer is washed twice with 30 g of purified water, and the recovered organic layer is concentrated. The solvent is removed from the resulting organic layer and then purified by column chromatography (ethyl acetate/hexane = 10/90 (volume ratio)) to obtain 5.6 g of 1-(4-methoxyphenyl)-2-phenylethanedione.

(Synthesis Example 54) Synthesis of 1-(4-hydroxyphenyl)-2-phenylethanedione

5.0 g of 1-(4-methoxyphenyl)-2-phenylethanedione is dissolved in 95 ml of acetic acid. 33.2 g of 48% by mass HBr aqueous solution is added dropwise to this at 70°C over 10 minutes. After addition, the mixture is stirred at 110°C for 70 hours. 150 g of water is then added to cause crystallization. This is then filtered, and the crystals are washed with 250 g of water and dried to obtain 4.1 g of 1-(4-hydroxyphenyl)-2-phenylethanedione.

(Synthesis Example 55) Synthesis of 2,2-dimethoxy-1-(4-methacryloxyphenyl)ethan-1-one (Compound C6)

4.0 g of 1-(4-hydroxyphenyl)-2-phenylethanedione and 0.10 g of sulfuric acid were dissolved in 12 g of methanol and the temperature was adjusted to 25°C. 2.2 g of trimethyl orthoformate was added dropwise to the solution and stirred for 3 hours. 0.6 g of triethylamine was added at 30°C and stirred for 5 minutes, after which the solvent was distilled off. 25 g of acetonitrile, 4.5 g of triethylamine, and 0.11 g of dimethylaminopyridine were added to the resulting residue, and then 6.8 g of methacrylic anhydride diluted with 5.0 g of acetonitrile was added dropwise at room temperature. After the dropwise addition, the mixture was stirred at 25°C for 2 hours, after which 64 g of a 3% by mass aqueous solution of NaHCO ₃ was added and stirred for 5 minutes. Thereafter, the residue is extracted with 32 g of ethyl acetate, washed three times with 10 g of water, and the collected organic layer is concentrated. The resulting organic layer is evaporated and then purified by column chromatography (ethyl acetate/hexane=10/90 (volume ratio)), thereby obtaining 4.3 g of 2,2-dimethoxy-1-(4-methacryloxyphenyl)ethan-1-one (compound C6).

<Synthesis of Compound E1 Constituting Unit E>
(Synthesis Example 56) Synthesis of 4-vinylphenyl-triphenyltin (Compound E1)

1.2 g of magnesium and 6 g of THF are added to a flask from which moisture has been removed. A solution of 6.0 g of 4-vinylbromobenzene dissolved in 12.0 g of THF is added dropwise over one hour. After stirring for one hour, the resulting 4-vinylphenylmagnesium bromide solution is added dropwise over 30 minutes at 5°C to a flask containing 7.3 g of triphenyltin chloride and 36 g of THF (prepared separately). After stirring for 30 minutes, 600 g of 1% ammonium chloride aqueous solution is added and stirred for an additional 10 minutes. The THF is then distilled off, and the mixture is extracted with 60 g of toluene. The resulting organic layer is separated and washed three times with 60 g of pure water. The organic layer obtained by separation is then distilled off and purified by column chromatography (ethyl acetate/hexane = 5/95 (volume ratio)) to obtain 5.6 g of 4-vinylphenyl-triphenyltin (Compound E1).

<Synthesis of Compound E2 Constituting Unit E>
(Synthesis Example 57) Synthesis of 4-isopropenylphenyl-triphenyltin (Compound E2)

By performing the same procedure as in Synthesis Example 56 above, except using 4-isopropenylbromobenzene instead of 4-vinylbromobenzene, 7.1 g of 4-isopropenylphenyl-triphenyltin (compound E2) is obtained.

<Synthesis of Compound E3 Constituting Unit E>
(Synthesis Example 58) Synthesis of 4-vinylphenyl-tributyltin (Compound E3)

By performing the same procedure as in Synthesis Example 56 above, except using tributyltin chloride instead of triphenyltin chloride, 5.1 g of 4-vinylphenyl-tributyltin (compound E3) is obtained.

<Synthesis of Compound E4 Constituting Unit E>
(Synthesis Example 59) Synthesis of 4-vinylphenyl-triphenylgermane (Compound E4)

By performing the same procedure as in Synthesis Example 56 above, except using triphenylgermanium chloride instead of triphenyltin chloride, 3.1 g of 4-vinylphenyl-tributylgermane (compound E4) is obtained.

<Synthesis of Compound F1 Constituting Unit F>
(Synthesis Example 60) Synthesis of 1-trifluoromethyl-2-bromoethanol

6.0 g of 1-bromo-3,3,3-trifluoroacetone was dissolved in 28 g of THF, 0.3 g of lithium aluminum hydride was added, and the mixture was stirred at room temperature for 3 hours. 6 g of purified water was then added while checking for hydrogen generation, and the mixture was stirred for an additional 10 minutes. A 5% by mass aqueous solution of sodium oxalate was added, and the mixture was stirred for 10 minutes. 30 g of ethyl acetate was then added and the mixture was separated. The mixture was washed three times with 10 g of water, and the collected organic layer was concentrated to obtain 5.9 g of 1-trifluoromethyl-2-bromoethanol.

(Synthesis Example 61) Synthesis of 1-trifluoromethyl-2-methacryloxyethanol (Compound F1)

5.0 g of 1-trifluoromethyl-2-bromoethanol was dissolved in 20 g of DMF, to which 3.9 g of potassium carbonate and 3.3 g of methacrylic acid were added, followed by stirring at 80°C for 3 hours. 20 g of purified water was then added and the mixture was stirred for an additional 10 minutes. 30 g of ethyl acetate was added and the mixture was separated. After that, the mixture was washed with 10 g of 1% by mass aqueous hydrochloric acid, and then washed three times with 10 g of water. The recovered organic layer was concentrated and purified by column chromatography (ethyl acetate/hexane = 10/90 (volume ratio)) to obtain 4.2 g of 1-trifluoromethyl-2-methacryloxyethanol (compound F1).

<Synthesis of Compound F2 Constituting Unit F>
(Synthesis Example 62) Synthesis of 1,3,5-triiodophenyl methacrylate (Compound F2)

By performing the same procedure as in Synthesis Example 46 above, except using 1,3,5-triiodophenol instead of 1-(4-hydroxyphenyl)-2,2-dimethyl-1-propanone, 4.3 g of 1,3,5-triiodophenyl methacrylate (compound F2) is obtained.

<Synthesis of Polymer 1>
(Synthesis Example 63) Synthesis of polymer a1

3.0 g of compound a1 constituting unit A, 1.8 g of compound B1 constituting unit B, 2.1 g of compound E1 constituting unit E, and 0.71 g of dimethyl-2,2'-azobis(2-methylpropionate) and 0.15 g of α-thioglycerol as polymerization initiators were dissolved in a mixed solution of 9 g of cyclohexanone and 13 g of γ-butyrolactone and deoxygenated. This solution was added dropwise over 4 hours to a mixed solution of 4 g of γ-butyrolactone and 4 g of cyclohexanone preheated to 80°C. After the dropwise addition, the mixture was stirred for 2 hours and then cooled. After cooling, the mixture was added dropwise to 90 g of ethyl acetate to reprecipitate. After filtering, the mixture was stirred in 40 g of 20% by weight aqueous methanol solution for 10 minutes, filtered, and vacuum dried to obtain 5.3 g of the target polymer 1.
Although the unit ratios of the polymers are disclosed above and below, the polymers of some embodiments of the present invention are not limited thereto.

(Synthesis Example 64) Synthesis of Polymer 1

2.0 g of polymer a1 obtained in Synthesis Example 63 above and 1.0 g of sodium 2-hydroxysulfonate are added to a mixed solution of 30 g of methylene chloride and 10 g of pure water, and the mixture is stirred at 25°C for 1 hour. After stirring, the mixture is separated, and another 1.0 g of sodium 2-hydroxysulfonate and 10 g of pure water are added, followed by stirring at 25°C for 30 minutes. This process is repeated three times, after which the mixture is separated and the recovered organic layer is concentrated. The solvent is distilled off from the resulting organic layer, which is then dispersed and washed with isopropyl alcohol to obtain 1.5 g of polymer 1.

(Synthesis Example 65) Synthesis of Polymer 2

1.4 g of polymer 2 is obtained by performing the same procedure as in Synthesis Example 64 above, except using 2,3-dihydroxypropanesulfonic acid instead of 2-hydroxysulfonic acid.

(Synthesis Example 66) Synthesis of Polymer 3

1.6 g of polymer 3 is obtained by performing the same procedure as in Synthesis Example 48 above, except that 3-[N,N-bis(2-hydroxyethyl)amino]-2-hydroxypropanesulfonic acid is used instead of 2-hydroxysulfonic acid.

<Synthesis of Polymers 4 to 13 and Comparative Polymers 1 and 2>
Synthesis Example 67 Synthesis of Polymers 4 to 13 and Comparative Polymers 1 and 2 Following the procedure of Synthesis Example 46, polymers 4 to 13 and comparative polymers 1 and 2 were synthesized using compounds A1 to A5, a1, and a2 constituting unit A, compounds B1, B2, and B4 constituting unit B, compounds C1, C2, and C6 constituting unit C, compound D below constituting unit D, compounds E1 to E3 constituting unit E, and compounds F1 to F2 constituting unit F. Details of each synthesized polymer are shown in Table 1.
Compound D: 4-hydroxyphenyl methacrylate

<Preparation of Resist Composition>
Of the above polymers, 50 mg of either Polymers 1, 4 to 6, or 8, or Comparative Polymers 1 and 2, was dissolved in a solvent containing cyclohexanone, ethyl lactate, and γ-butyrolactone in a ratio of 5:5:1 to prepare resist composition samples 1 to 7 of Examples 1 to 5 and Comparative Examples 1 and 2. The polymers used are shown in Tables 2 and 3.

<Preparation of Developer>
The developer was prepared as follows.
(1) Resist composition samples 1 to 7, in which the above polymers 1, 4 to 6, and 8 and comparative polymers 1 and 2 were dissolved, were used to prepare films coated with the composition to a thickness of 100 nm by spin coating.
(2) An aqueous acetonitrile solution having an acetonitrile concentration of 0 to 80% by mass is prepared.
(3) Each film obtained in (1) above is immersed in each aqueous acetonitrile solution, and the minimum acetonitrile concentration in the aqueous acetonitrile solution at which the composition applied to the film is completely dissolved within 30 seconds is determined.
(4) The aqueous acetonitrile solution obtained in (3) above is used as the developer for each resist composition sample.

<Electron beam sensitivity evaluation>
The resist composition sample 1 was spin-coated onto a silicon wafer. This was pre-baked on a hot plate at 110°C for 1 minute to obtain a substrate with a 30 nm thick coating film. A 50 nm line pattern with a 160 nm pitch was written onto the coating film on the substrate using an electron beam lithography system (Elionix ELS-F100T) with a 125 keV electron beam. After electron beam irradiation, the substrate was post-exposure baked (PEB) for 1 minute on a hot plate at 90°C. The substrate was then developed for 1 minute using a patterning developer in which the acetonitrile concentration of the developer optimized for each polymer was increased by 5% by mass, followed by rinsing with pure water to obtain a 50 nm line pattern. The exposure dose at this time was defined as E _max [μC/cm ² ], and the sensitivity due to electron beam irradiation was determined. The resulting 50 nm line pattern is observed using a scanning electron microscope (SEM) (S-5500 manufactured by Hitachi High-Technologies Corporation) to measure the LWR.
The sensitivity and LWR were evaluated in the same manner as above for Samples 2 to 7. The sensitivity and LWR of each of Resist Composition Samples 2 to 7 were compared using the sensitivity and LWR of Resist Composition Sample 1 (Comparative Example 1) as the reference values, and the results obtained as relative sensitivity and relative LWR are shown in Table 2.

The results of Examples 1 and 2 show that both polymers have a hydroxyl group in the anion of unit A, allowing the hydroxyl group in the anion to react with unit B. As a result, Examples 1 and 2 improve reaction efficiency, achieving a sensitivity increase of 15% or more compared to Comparative Example 1. Furthermore, when a polymer having a hydroxyl group in the anion of unit A reacts with unit B, the acid anion becomes part of the polymer, significantly improving acid diffusion controllability and enabling a reduction in LWR of 30% or more compared to Comparative Example 1.

Examples 3 and 4 have the same cationic structure as Comparative Example 2, but are able to achieve a sensitivity increase of more than 15% compared to Comparative Example 2. Comparative Example 2 has higher sensitivity than Comparative Example 1, but also has a 20% higher LWR than Comparative Example 1. However, because Examples 3 and 4 use a polymer with a hydroxyl group in the anion of Unit A, they have better sensitivity than Comparative Example 1 and can achieve a lower LWR of more than 30%.

The results of Example 5 show that anions having thiols, like anions having hydroxyl groups, can improve sensitivity and reduce LWR compared to the reference example.

<Synthesis of Polymers 14 to 20>
Synthesis Example 68: Synthesis of Polymers 14 to 21
Polymers 14 to 21 were synthesized using the compounds B1, B2, and B4 constituting unit B, the compounds C1, C2, and C6 constituting unit C, the compound E1 constituting unit E, and the following compound K constituting unit K. Details of each synthesized polymer are shown in Table 3.
Compound K: 9-(4-methacryloxyphenyl)dibenzothiophenium-2,4,6-trifluorobenzoate

[Examples 6 to 13]
<Preparation of Resist Composition>
50 mg of any of the above polymers 4, and 14 to 21 was dissolved in a solvent containing cyclohexanone, ethyl lactate, and γ-butyrolactone in a ratio of 5:5:1 to prepare resist composition samples 8 to 16 of Examples 6 to 14. The polymers used are shown in Table 4.

<Preparation of Developer>
The developer was prepared as follows.
(1) Resist composition samples 8 to 15, in which the above polymers 4 and 14 to 20 were dissolved, were used to prepare films coated with the composition to a thickness of 100 nm by spin coating.
(2) An aqueous acetonitrile solution having an acetonitrile concentration of 0 to 80% by mass is prepared.
(3) Each film obtained in (1) above is immersed in each aqueous acetonitrile solution, and the minimum acetonitrile concentration in the aqueous acetonitrile solution at which the composition applied to the film is completely dissolved within 30 seconds is determined.
(4) The aqueous acetonitrile solution obtained in (3) above is used as the developer for each resist composition sample.

<Electron beam-UV sensitivity evaluation>
The resist composition sample 8 was spin-coated onto a silicon wafer. This was pre-baked on a hot plate at 110°C for 1 minute to obtain a substrate with a 30 nm thick coating film. A 50 nm line pattern with a 160 nm pitch was written onto the coating film on the substrate using an electron beam lithography system (Elionix ELS-F100T) with a 125 keV electron beam. After electron beam irradiation, the substrate was post-exposure baked (PEB) on a hot plate at 90°C for 1 minute. The entire surface was then irradiated with a 395 nm UV-LED at an exposure dose of 1000 mJ/ ^cm² . The wafer was then developed for 1 minute using a patterning developer optimized for each polymer, with the acetonitrile concentration increased by 5% by mass, followed by rinsing with pure water to obtain a 50 nm line pattern. The sensitivity to electron beam irradiation was calculated using the exposure dose E _max [μC/ ^cm² ]. The resulting 50 nm line pattern is observed using a scanning electron microscope (SEM) (S-5500 manufactured by Hitachi High-Technologies Corporation) to measure the LWR.
The sensitivity and LWR were evaluated in the same manner as above for Samples 9 to 16. The sensitivity and LWR of each of Resist Composition Samples 9 to 16 were compared using the sensitivity and LWR of Resist Composition Sample 8 as reference values, and the results obtained as relative sensitivity and relative LWR are shown in Table 4.

Example 6, which has the same composition ratio of units A, B, and E, was compared with Examples 7 to 10. The hydroxyl groups of the anions of compounds A7 to A10 contained in Examples 7 to 10 are bonded to unit B through an acid-catalyzed reaction with acid generated by electron beam irradiation. Unit B also bonds to each other through an acid-catalyzed reaction. Furthermore, the acetal moiety of the onium salt in unit A is hydrolyzed by water generated by the acid-catalyzed reaction to form a ketone derivative, shifting the light absorption wavelength to longer wavelengths, and the polymer changes to have UV absorption at 395 nm. Therefore, further acid generation by full-surface UV exposure after EB irradiation improves the sensitivity of Examples 7 to 10, even though they have the same composition as Example 6.

Comparing Example 6 with Examples 7 to 13, it is estimated that even though sensitivity to UV irradiation is improved, the impact of acid diffusion due to UV irradiation is negligible due to the good LWR. Comparing Example 6 with Examples 7 to 13, patterning is possible with a similar LWR, so there is no trade-off between sensitivity and LWR.

Comparing Example 8 and Example 14, it can be seen that adding Unit K reduces sensitivity by suppressing the action of the acid generated from Unit A, but also tends to reduce LWR by suppressing acid diffusion. This is effective when high resolution is required.

Some aspects of the present invention make it possible to provide a polymer that has high absorption efficiency for particle beams or electromagnetic waves such as EUV, and has excellent sensitivity, resolution, and pattern performance properties, as well as a resist composition containing the polymer.

Claims (28)

a unit A having an onium salt structure and generating an acid when irradiated with a particle beam or electromagnetic wave;
and a unit B having a structure that bonds via an acid-catalyzed reaction,
The unit A is a unit represented by the following formula (1):
(In the general formula (1),
R ¹ is any one selected from the group consisting of a hydrogen atom; a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms; and a linear, branched, or cyclic alkenyl group having 1 to 6 carbon atoms; and at least one hydrogen atom in the alkyl group and alkenyl group in R ¹ may be substituted with a substituent,
L is any one selected from the group consisting of a direct bond, a carbonyloxy group, a carbonylamino group, a phenylenediyl group, a naphthalenediyl group, a phenylenediyloxy group, a naphthalenediyloxy group, a phenylenediylcarbonyloxy group, a naphthalenediylcarbonyloxy group, a phenylenediyloxycarbonyl group, and a naphthalenediyloxycarbonyl group;
Sp is any one of a direct bond; an optionally substituted linear, branched or cyclic alkylene group having 1 to 6 carbon atoms; and an optionally substituted linear, branched or cyclic alkenylene group having 1 to 6 carbon atoms, wherein at least one methylene group in Sp is optionally substituted with a divalent heteroatom-containing group,
M ⁺ is a sulfonium ion or an iodonium ion;
X ⁻ is a monovalent anion having an organic group containing at least one selected from the group consisting of a hydroxyl group and a sulfanyl group.
The polymer wherein the unit B is a unit in which a compound represented by the following general formula (I) or (II) is bonded to an Sp group of the following formula (2) at any position of the compound:
(In the general formula (I),
R2 and R3 ^are each independently any one selected from the group consisting of a hydrogen atom; an electron-donating group; and an electron-withdrawing group ^;
E is any one selected from the group consisting of a direct bond; an oxygen atom; a sulfur atom; and a methylene group;
n1 is an integer of 0 or 1 ^;
n4 and n5 ^are each an integer of 1 to 2, and n4 ^{+ n5} is ^an integer of 2 to 4;
When n4 is 1, n2 ^{is an} integer from 0 to 4, and when n4 ^is 2, n2 ^is an integer from 0 to 6;
When n5 is 1, n3 ^{is an} integer of 0 to 4, and when n5 ^is 2, n3 ^is an integer of 0 to 6;
when n2 is 2 or greater and R2 ^{is an} electron-donating group or an electron-withdrawing group, two R2s ^may form a ring structure together directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen-containing group, and a methylene group,
When n3 is 2 or more and R3 ^{is an} electron-donating group or an electron-withdrawing group, two R3s ^may form a ring structure together directly by a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen-containing group, and a methylene group.
In the general formula (II),
R4 is independently any one selected from the group consisting of a hydrogen atom; an electron-donating group; and an electron-withdrawing group ^;
At least one of R4 is the electron-donating group ^;
R5 is any one selected from the group consisting of a hydrogen atom; an alkyl group which may have a substituent; and an alkenyl group which may have a substituent; at least one methylene group in R5 ^{may be} substituted with a divalent heteroatom-containing group, and R5 ^may form a ring structure together with the benzene ring to which the hydroxymethylene group having ^R5 is bonded,
n6 is an integer from 0 to 7 ^;
n7 is 1 or 2, and when n7 ^is 1, n6 ^{is an} integer of 0 to 5, and when n7 ^is 2, n6 ^is an integer of 0 to 7;
When n6 is 2 or more and R4 ^{is an} electron-donating group or an electron-withdrawing group, two R4s ^may form a ring structure together directly by a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen-containing group, and a methylene group.
(In the formula (2),
R ¹ , L and Sp are selected from the same options as R ¹ , L and Sp in general formula (1), respectively;
* indicates the bonding site with the compound represented by the general formula (I) or (II). at least one hydroxyl group of the organic group is derived from any one selected from the group consisting of primary alcohols, secondary alcohols, and tertiary alcohols;
2. The polymer according to claim 1, wherein the sulfanyl group of at least one of the organic groups is derived from any one selected from the group consisting of primary thiols, secondary thiols, and tertiary thiols. at least one hydroxyl group of the organic group is derived from a primary alcohol or a secondary alcohol;
3. The polymer according to claim 1, wherein the sulfanyl group of at least one of the organic groups is derived from a group selected from the group consisting of primary thiols and secondary thiols. X ⁻ is any one selected from the group consisting of an alkyl sulfate anion having at least one hydroxyl group and a sulfanyl group; an aryl sulfate anion having at least one hydroxyl group and a sulfanyl group; an alkylsulfonate anion having at least one hydroxyl group and a sulfanyl group; an arylsulfonate anion having at least one hydroxyl group and a sulfanyl group; an alkylcarboxylate anion having at least one hydroxyl group and a sulfanyl group; an arylcarboxylate anion having at least one hydroxyl group and a sulfanyl group; a dialkylsulfonylimide anion having at least one hydroxyl group and a sulfanyl group; a trialkylsulfonatemethide anion having at least one hydroxyl group and a sulfanyl group; and a tetrakisphenylborate anion having at least one hydroxyl group and a sulfanyl group;
4. The polymer according to claim 1, wherein at least one hydrogen atom of the alkyl group and aryl group in X ^{1 -} may be substituted with a fluorine atom. X ⁻ is either an alkylsulfonate anion having at least one hydroxyl group and one sulfanyl group, or an arylsulfonate anion having at least one hydroxyl group and one sulfanyl group;
5. The polymer according to claim 4, wherein at least one hydrogen atom of the alkyl group and aryl group in X ^{1 -} may be substituted with a fluorine atom. the polymer further comprises a unit C;
the unit C has a radical-generating structure containing at least one multiple bond selected from the group consisting of a multiple bond between carbon atoms and a multiple bond between a carbon atom and a heteroatom, and generates a second radical when irradiated with a particle beam or an electromagnetic wave,
6. The polymer according to claim 1 , wherein the multiple bond in the radical-generating structure is not a multiple bond contained in a benzene-based aromatic compound. The polymer according to claim 6 , wherein the multiple bond is at least one of the bonds shown below:
The polymer according to claim 6 or 7 , wherein the unit C has any one selected from the group consisting of an alkylphenone skeleton, an acyloxime skeleton, and a benzil ketal skeleton. The polymer according to any one of claims 1 to 8 , wherein the unit A is represented by the following formula (3):
(In the general formula (3),
R ¹ , L, Sp and X ⁻ are selected from the same options as R ¹ , L, Sp and X ⁻ in the general formula (1), respectively;
R ^6a is any one selected from the group consisting of an optionally substituted linear, branched or cyclic alkylene group having 1 to 6 carbon atoms; an optionally substituted linear, branched or cyclic alkenylene group having 1 to 6 carbon atoms; an optionally substituted arylene group having 6 to 14 carbon atoms; an optionally substituted heteroarylene group having 4 to 12 carbon atoms; and a direct bond; wherein at least one methylene group in R ^6a is optionally substituted with a divalent heteroatom-containing group,
R ^6b each independently represents any one selected from the group consisting of an optionally substituted linear, branched or cyclic alkyl group having 1 to 6 carbon atoms; an optionally substituted linear, branched or cyclic alkenyl group having 1 to 6 carbon atoms; an optionally substituted aryl group having 6 to 14 carbon atoms; and an optionally substituted heteroaryl group having 4 to 12 carbon atoms, wherein at least one methylene group in R ^6b is optionally substituted with a divalent heteroatom-containing group,
R ^6a and two of the two R ^6b may form a ring structure with the sulfur atom to which they are bonded directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen atom-containing group, and a methylene group. 9. The polymer according to claim 1 , wherein M ⁺ X ⁻ is represented by the following general formula (11) or the following formula (12):
(In the formulas (11) and (12),
R ¹⁴ is independently any one selected from the group consisting of an alkyl group, a hydroxy group, a mercapto group, an alkoxy group, an aryloxycarbonyl group, a heteroaryloxycarbonyl group, an arylsulfanylcarbonyl group, a heteroarylsulfanylcarbonyl group, an arylsulfanyl group, a heteroarylsulfanyl group, an alkylsulfanyl group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, a (poly)alkyleneoxy group, an alkylamino group, and a dialkylcyano group;
R ¹⁷ and R ¹⁸ are each independently any one selected from the group consisting of an alkyl group, a hydroxy group, a mercapto group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, a heteroarylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a heteroaryloxycarbonyl group, an arylsulfanylcarbonyl group, a heteroarylsulfanylcarbonyl group, an arylsulfanyl group, a heteroarylsulfanyl group, an alkylsulfanyl group, an aryl group, a heteroaryl group, an aryloxy group, a heteroaryloxy group, an alkylsulfinyl group, an arylsulfinyl group, a heteroarylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a heteroarylsulfonyl group, an arylsulfonyl group, a heteroarylsulfonyl group, a (poly)alkyleneoxy group, an alkylamino group, a dialkylamino group, a nitro group, and a halogen atom;
When R ¹⁴ , R ¹⁷ and R ¹⁸ each have a carbon atom, the number of carbon atoms is 1 to 12, and when R ¹⁴ , R ¹⁷ and R ¹⁸ each have a hydrogen atom, the hydrogen atom may be substituted with a substituent;
R ¹⁹ is any one selected from the group consisting of an optionally substituted linear, branched or cyclic alkyl group having 1 to 12 carbon atoms; an optionally substituted linear, branched or cyclic alkenyl group having 1 to 12 carbon atoms; an optionally substituted aryl group having 6 to 14 carbon atoms; and an optionally substituted heteroaryl group having 4 to 12 carbon atoms;
R ¹⁹ and either the benzene ring to which R ¹⁸ is bonded or the benzene ring to which R ¹⁷ is bonded may form a ring structure together with the sulfur atom to which they are bonded, either directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom-containing group and a methylene group;
When R ¹⁴ , R ¹⁷ and R ¹⁸ each have a methylene group, at least one of the methylene groups may be substituted with a divalent heteroatom-containing group;
R ¹⁵ and R ¹⁶ are each independently any one selected from the group consisting of an optionally substituted linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms; an optionally substituted linear, branched, or cyclic alkenyl group having 1 to 12 carbon atoms; an optionally substituted aryl group having 6 to 14 carbon atoms; and an optionally substituted heteroaryl group having 4 to 12 carbon atoms;
R ¹⁵ and R ¹⁶ may be bonded to each other directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, and an alkylene group to form a ring structure;
At least one methylene group in R ¹⁵ and R ¹⁶ may be substituted with a divalent heteroatom-containing group,
^L3 is any one selected from the group consisting of a direct bond; a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms; an alkenylene group having 2 to 12 carbon atoms; a sulfinyl group, a sulfonyl group, and a carbonyl group;
any one hydrogen atom among R ¹⁴ , R ¹⁸ and R ¹⁹ is replaced with a bond to Sp in the formula (1);
Y is an oxygen atom or a sulfur atom,
q is an integer from 0 to 4;
f is an integer from 0 to 3;
g is an integer from 1 to 5;
j is an integer from 0 to 2,
k is an integer from 1 to 4,
(However, when R ¹⁹ and either the benzene ring to which R ¹⁸ is bonded or the benzene ring to which R ¹⁷ is bonded together with the sulfur atom form a ring structure, in the formula (11), q is 0 to 3 or j is 0 to 2, and in the formula (12), q is 0 to 3 or j is 0 to 1.)
At least one of the benzene rings in the formulae (11) and (12) may be a 6-membered heteroaromatic ring having a heteroatom in the ring, and when the benzene ring bonded to R ¹⁴ in the formulae (11) and (12) is the heteroaromatic ring, k may be 0 to 4.
When two or more R ^14s are present in the formulae (11) and (12), two of the R ^14s may be bonded to each other to form a ring structure,
X ⁻ is selected from the same options as X ⁻ in formula (1). The polymer according to any one of claims 6 to 10 , wherein the unit C is represented by at least one of the following general formulas (4):
(In the general formula (4),
R ¹ , L, Sp and X ⁻ are selected from the same options as R ¹ , L, Sp and X ⁻ in the general formula (1), respectively;
R ⁷ is independently any one selected from the group consisting of a hydrogen atom; a hydroxy group; -R ^a (R ^a is a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms which may have a substituent, and at least ^one methylene group in R a may be substituted with a divalent heteroatom-containing group); -OR ^a ; and a group in which at least one carbon-carbon single bond in R ^a is substituted with a carbon-carbon double bond; and -R ^b (R ^b is an aryl group having 6 to 14 carbon atoms which may have a substituent or a heteroaryl group having 4 to 12 carbon atoms which may have a substituent);
two ^R7s may form a ring structure together directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen atom-containing group, and a methylene group;
R ⁸ is -R ^a ;-R ^b ;-OR ^a ;-SR ^a ;-OR ^b ;-SR ^b ;-OC(=O)R ^a ;-OC(=O)R ^b ;-C(=O)OR ^a ;-C(=O)OR ^b ;-OC(=O)OR ^a ;-OC(=O)OR ^b ;-NHC(=O)R ^a ;-NR ^a C(=O)R ^a ;-NHC(=O)R ^b ;-NR ^b C(=O)R ^b ;-NR ^a C(=O)R ^b ;-NR ^b C(=O)R ^a ;-N(R ^a ) ₂ ;-N(R ^b ) ₂ ;-N(R ^a )(R ^b _a group in which at _{least one} carbon-carbon single bond in -R ^a is replaced with ^a carbon-carbon double bond; and a nitro group; m 2 is an integer of 1 to 3, and when ^m 2 is 1 ^{, m 1} _is an integer of 0 ^to 4, when m ² is 2, m ¹ is an integer of 0 to 6, and when m ² is 3 ^, m ¹ is an integer of 0 to 8,
When ^m1 is 2 or more, two ^R8s may form a ring structure together directly via a single bond or via any one selected from the group consisting of an oxygen atom, a sulfur atom, a divalent nitrogen atom-containing group, and a methylene group. The polymer according to claim 11 , wherein the unit C is represented by the general formula (4), and at least one of ^R7 in the general formula (4) is a hydroxy group. The polymer according to any one of claims 1 to 12 , further comprising a unit D having an aryloxy group. The polymer according to any one of claims 1 to 13 , further comprising an organometallic compound-containing unit E having a metal atom selected from the group consisting of Sn, Sb, Ge, Bi and Te. The polymer according to any one of claims 1 to 14 , further comprising a unit F having a halogen atom and represented by the following formula (7):
(In the general formula (7),
R ¹ , L and Sp are selected from the same options as R ¹ , L and Sp in general formula (1), respectively;
^Rh is any one selected from the group consisting of an optionally substituted linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms; an optionally substituted linear, branched, or cyclic alkyleneoxy group having 1 to 12 carbon atoms; an optionally substituted linear, branched, or cyclic alkenyl group having 1 to 12 carbon atoms; an optionally substituted linear, branched, or cyclic alkenyleneoxy group having 1 to 12 carbon atoms; an optionally substituted aryl group having 6 to 14 carbon atoms; and an optionally substituted heteroaryl group having 4 to 12 carbon atoms;
In addition, some or all of the hydrogen atoms substituted on the carbon atoms are substituted with fluorine atoms or iodine atoms. A resist composition comprising the polymer according to any one of claims 1 to 15 . Further containing either an organometallic compound or an organometallic complex,
17. The resist composition according to claim 16, wherein the metal is at least one selected from the group consisting of Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, I, Xe, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, At, Rn, and Ra . a resist film forming step of forming a resist film on a substrate using the resist composition according to claim 16 or 17 ;
a photolithography step of exposing the resist film to particle beams or electromagnetic waves;
a pattern formation step of developing the exposed resist film to obtain a photoresist pattern;
A method for manufacturing a component comprising: The method for manufacturing a member according to claim 18 , wherein the development in the pattern formation step is carried out using an aqueous solution containing a water-soluble organic solvent. The method for manufacturing a member according to claim 18 or 19 , wherein in the photolithography step, after exposure to the particle beam or electromagnetic wave, irradiation with a second active energy ray having lower energy than the particle beam or electromagnetic wave is performed. a step of applying a reversal pattern composition so as to cover at least the recesses of the photoresist pattern, and etching the resulting coating to expose the surface of the photoresist pattern;
The method for manufacturing a member according to any one of claims 18 to 20 , further comprising the step of removing the resist film from the exposed surface portion of the resist pattern to obtain a reverse pattern. The method for manufacturing a member according to any one of claims 18 to 21 , wherein the particle beam is an electron beam and the electromagnetic wave is extreme ultraviolet radiation. a resist film forming step of forming a resist film on a substrate using the resist composition according to claim 16 or 17 ;
a photolithography step of exposing the resist film to particle beams or electromagnetic waves;
and a pattern forming step of developing the exposed resist film to obtain a photoresist pattern. 24. The pattern formation method according to claim 23 , wherein the development in the pattern formation step is carried out using an aqueous solution containing a water-soluble organic solvent. 25. The pattern formation method according to claim 23 , wherein in the photolithography step, after exposure to the particle beam or electromagnetic wave, irradiation with a second active energy ray having lower energy than the particle beam or electromagnetic wave is performed. a resist film forming step of forming a resist film on a substrate using the resist composition according to claim 16 or 17 ;
a photolithography step of exposing the resist film to particle beams or electromagnetic waves;
a pattern formation step of developing the exposed resist film to obtain a photoresist pattern;
a step of applying a reversal pattern composition so as to cover at least the recesses of the photoresist pattern, and etching the resulting coating to expose the surface of the photoresist pattern;
and removing the resist film from the exposed surface portion of the photoresist pattern to obtain a reverse pattern. 27. The method for forming a reversal pattern according to claim 26 , wherein the development in the pattern formation step is carried out using an aqueous solution containing a water-soluble organic solvent. 28. The method for forming a reversal pattern according to claim 26 , wherein in the photolithography step, after exposure to the particle beam or electromagnetic wave, a second active energy ray having lower energy than the particle beam or electromagnetic wave is irradiated.