JP5764297B2 - Resist pattern forming method and resin purification method - Google Patents

Description

  The present invention relates to a resist pattern forming method in which patterning is performed twice or more, and a method for purifying a resin used therefor.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to light such as light or an electron beam through a mask on which a predetermined pattern is formed. And a development process is performed to form a resist pattern having a predetermined shape on the resist film. A resist material in which the exposed portion changes to a property that dissolves in the developer is referred to as a positive type, and a resist material that changes to a property in which the exposed portion does not dissolve in the developer is referred to as a negative type.
In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has been rapidly progressing due to advances in lithography technology.
As a technique for miniaturization, the exposure light source is generally shortened in wavelength (increased energy). Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but at present, mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has started. Further, studies have been made on electron beams having shorter wavelengths (higher energy) than these excimer lasers, EUV (extreme ultraviolet rays), X-rays, and the like.

  Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions. As a resist material satisfying such requirements, a chemically amplified resist composition containing a base resin whose solubility in an alkaline developer is changed by the action of an acid, an acid generator that generates an acid upon exposure, and an organic solvent. Is used. For example, a positive-type chemically amplified resist composition is formed by dissolving a resin whose solubility in an alkali developer increases as a base resin due to the action of an acid and an acid generator in an organic solvent. Sometimes, when an acid is generated from the acid generator by exposure, the exposed portion becomes soluble in an alkaline developer.

Up to now, as a base resin used in a chemically amplified resist, polyhydroxystyrene (PHS) having high transparency with respect to a KrF excimer laser (248 nm) and a resin (PHS) whose hydroxyl group is protected with an acid dissociable, dissolution inhibiting group. Based resins) have been used. However, since the PHS resin has an aromatic ring such as a benzene ring, the transparency to light having a wavelength shorter than 248 nm, for example, 193 nm, is not sufficient. For this reason, a chemically amplified resist having a PHS resin as a base resin component has drawbacks such as low resolution in a process using 193 nm light, for example.
Therefore, as a resist base resin currently used in ArF excimer laser lithography and the like, since it has excellent transparency near 193 nm, a resin (acrylic resin) having a structural unit derived from (meth) acrylic ester is used. Resin) is mainly used (for example, see Patent Document 1).

A wide variety of acid generators used in chemically amplified resists have been proposed. For example, onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, diazomethane series, and the like. Acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like are known.
Currently, an onium salt acid generator having an onium ion such as triphenylsulfonium in the cation moiety is used as the acid generator. The anion moiety of the onium salt acid generator is generally an alkyl sulfonate ion or a fluorinated alkyl sulfonate ion in which some or all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms.

  In addition, as the chemically amplified resist used in ArF excimer laser lithography and the like, the acrylic resin and the acid generator are mixed with propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone (CH). A resist composition dissolved in an organic solvent such as 2-heptanone or ethyl lactate (EL) is often used.

As one of the methods for further improving the resolution of the resist pattern, exposure is performed by interposing a liquid (immersion medium) having a refractive index higher than that of air between the objective lens of the exposure machine and the sample ( A lithography method for performing immersion exposure), so-called liquid immersion lithography (hereinafter sometimes referred to as “immersion exposure”) is known (for example, see Non-Patent Document 1).
According to immersion exposure, even when a light source having the same exposure wavelength is used, the same high resolution as when using a light source with a shorter wavelength or using a high NA lens can be achieved, and the depth of focus can be reduced. It is said that there is no decline. In addition, immersion exposure can be performed by applying an existing exposure apparatus. For this reason, immersion exposure is expected to be able to form resist patterns with low cost, high resolution, and excellent depth of focus. In particular, in terms of lithography characteristics such as resolution, the semiconductor industry is attracting a great deal of attention.
Immersion exposure is effective in forming all pattern shapes, and can be combined with super-resolution techniques such as the phase shift method and the modified illumination method that are currently being studied. Currently, as an immersion exposure technique, a technique mainly using an ArF excimer laser as a light source is being actively researched. Currently, water is mainly studied as an immersion medium.

  In immersion exposure, in addition to normal lithography characteristics (sensitivity, resolution, etching resistance, etc.), a resist material having characteristics corresponding to the immersion exposure technique is required. For example, in immersion exposure, when the resist film and the immersion solvent come into contact with each other, elution of the substance in the resist film into the immersion solvent (substance elution) occurs. Since the amount of this substance elution is affected by the characteristics (for example, hydrophilicity / hydrophobicity) of the resist film surface, for example, the elution of the substance can be reduced by increasing the hydrophobicity of the resist film surface.

Further, as a recently proposed lithography technique, there is a double patterning process in which patterning is performed twice or more to form a resist pattern (see, for example, Non-Patent Documents 2 to 3).
In this double patterning process, for example, a first resist film is formed on a support, a plurality of resist patterns are formed by patterning the first resist film, and then a second resist material is formed thereon. By applying, forming a second resist film between the plurality of resist patterns, and patterning the second resist film, a resist pattern having higher resolution than a resist pattern formed by one patterning Can be formed.

JP 2003-241385 A

Proceedings of SPIE, 5754, 119-128 (2005). Proceedings of SPIE, 5256, 985-994 (2003). Proceedings of SPIE, 6153, 615301-1-19 (2006).

However, in the double patterning process as described above, for example, there is a problem that the first resist pattern is easily damaged when the second patterning is performed. Specifically, for example, the film thickness is decreased, the resist film thickness is decreased, the shape of the first resist pattern is changed, the line width of the line pattern is decreased (pattern thinning), the roughness is generated, the first There is a problem that the resist pattern itself disappears.
This problem occurs due to the influence of the organic solvent used for the second resist material or the influence of exposure in the second patterning. Such a problem is more likely to occur as the first resist film becomes thinner or as the size of the resist pattern to be formed on the first resist film becomes smaller.

There is a technique for protecting the first resist pattern using, for example, a freezing agent after the first patterning in order to prevent the resist pattern shape defect as described above. However, this technique is not preferable in terms of throughput improvement.
Therefore, in the formation of a resist pattern by double patterning, for example, the second chemically amplified resist composition is directly applied onto the first resist pattern formed using the first chemically amplified resist composition. When the second resist film is formed and the second resist patterning is performed to form a fine resist pattern, it is necessary to suppress damage to the first resist pattern.

  The present invention has been made in view of the above circumstances, and in a double patterning process, a resist pattern forming method capable of forming a resist pattern that is not easily affected by the second and subsequent patterning, and a method for purifying a resin used therefor. The issue is to provide.

In order to solve the above problems, the present invention employs the following configuration.
That is, the resist pattern forming method of the present invention contains a resin (A1) and an organic solvent (S1) that dissolves the resin (A1) on a support, and the solubility in an alkali developer changes upon exposure. Applying a first resist material to form a first resist film, selectively exposing the first resist film, and performing alkali development to form a first resist pattern; On the support on which the resist pattern is formed, the resin (A2) and an organic solvent (S2) that dissolves the resin (A2) and does not dissolve the resin (A1) are contained. Forming a second resist film by applying a second resist material whose solubility in the liquid is changed, selectively exposing the second resist film, and performing alkali development to form a resist pattern; including A resist pattern forming method, the resin organic solvent which dissolves the (A1) (S4) to the resin (A1) is dissolved resin (A1) solution (excluding the polymerization solution of the resin (A1)) , the resin (A1) which was purified by washing with a washing solution containing an organic solvent (W) to dissolve and the resin does not dissolve the resin (A1) (A2), the first resist material It is characterized by blending.

The method for purifying a resin of the present invention comprises a resin (A1) and an organic solvent (S1) for dissolving the resin (A1) on a support, and the solubility in an alkali developer is changed by exposure. Applying a first resist material to form a first resist film, selectively exposing the first resist film, and performing alkali development to form a first resist pattern; On the support on which the resist pattern is formed, the resin (A2) and an organic solvent (S2) that dissolves the resin (A2) and does not dissolve the resin (A1) are contained. Forming a second resist film by applying a second resist material whose solubility in the liquid is changed, selectively exposing the second resist film, and performing alkali development to form a resist pattern; Including resist putter The resin (A1) is purified by a forming method, and a resin (A1) solution in which the resin (A1) is dissolved in an organic solvent (S4) that dissolves the resin (A1) (however, the resin (A1 At least one selected from the group consisting of a fluorine- based organic solvent, an ether-based organic solvent having no hydroxyl group , and an alcohol-based organic solvent having a boiling point of 80 to 250 ° C. under normal pressure. It is characterized by washing with an organic solvent containing

In the present specification and claims, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
Unless otherwise specified, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups.
The “lower alkyl group” is an alkyl group having 1 to 5 carbon atoms.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
“Aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, etc. that do not have aromaticity.
“Structural unit” means a monomer unit (monomer unit) constituting a polymer compound (polymer, copolymer).
“Exposure” is a concept including general irradiation of radiation.

“(Meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position.
“(Meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.
“(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.

  ADVANTAGE OF THE INVENTION According to this invention, in the double patterning process, the resist pattern formation method which can form the resist pattern which is hard to be influenced by the patterning of the 2nd time or later, and the purification method of resin used for this can be provided.

It is a figure which shows the chromatogram measured by the gel permeation chromatography (GPC) about the high molecular compound of the comparative example 1, and the high molecular compound which performed the purification method of Example 1,2.

≪Resist pattern formation method≫
The method for forming a resist pattern of the present invention comprises a resin (A1) and an organic solvent (S1) for dissolving the resin (A1) on a support, and the solubility in an alkaline developer is changed by exposure. A step of applying a resist material to form a first resist film, selectively exposing the first resist film, and performing alkali development to form a first resist pattern (hereinafter referred to as “patterning step (1) And the organic solvent (S2) that dissolves the resin (A2) and the resin (A2) and does not dissolve the resin (A1) on the support on which the first resist pattern is formed. ), A second resist material whose solubility in an alkali developer is changed by exposure is applied to form a second resist film, and the second resist film is selectively exposed to alkali development. And resist Forming a turn (hereinafter referred to as "patterning step (2)".) And the method comprising.
Hereinafter, the resist pattern forming method of the present invention will be described in more detail.

In the resist pattern forming method of the present invention, a first resist material and a second resist material are used.
The first resist material contains a resin (A1) and an organic solvent (S1) that dissolves the resin (A1) (hereinafter also referred to as “component (S1)”), and is dissolved in an alkaline developer by exposure. Sex changes.
The second resist material contains a resin (A2) and an organic solvent (S2) (hereinafter also referred to as “component (S2)”) that dissolves the resin (A2) and does not dissolve the resin (A1). However, the solubility in an alkaline developer is changed by exposure.
In the resist pattern forming method, the first resist material, which is selected so as to satisfy the above relationship, is blended with the resin (A1) and the organic solvent (S1), and the resin (A2) and the organic solvent (S2), respectively. And a second resist material.
Specific examples of compounding components in the first resist material and the second resist material will be described in detail later.

  In the present invention, the resin (A1) is a cleaning liquid containing an organic solvent (W) that does not dissolve the resin (A1) and dissolves the resin (A2) (hereinafter also referred to as “component (W)”). It refine | purifies by washing | cleaning and mix | blends with a 1st resist material, and a 1st resist pattern is formed using the 1st resist material by a patterning process (1).

(Cleaning solution)
The cleaning liquid contains the organic solvent (W).
The component (W) may be any component that does not dissolve the resin (A1) and dissolves the resin (A2), and may be the same as or different from the organic solvent (S2) described later.
In the present invention, “resin (A1) is not dissolved and resin (A2) is dissolved” in component (W) means that resin (A1) is dissolved in 100 g of component (W) under the condition of 25 ° C. It indicates that the amount is 3 g or less and the amount of the resin (A2) dissolved is 10 g or more.
Among these, as the component (W), an alcohol organic solvent, a fluorine organic solvent, a resist pattern that is not easily affected by the second and subsequent patterning can be easily formed by using the resin (A1) for purification. And at least one selected from the group consisting of ether-based organic solvents having no hydroxyl group. Among them, an alcohol-based organic solvent is preferable since the resin (A1) can be purified well and the resin (A2) has good solubility.

Here, the “alcohol-based organic solvent” is a compound in which at least one of the hydrogen atoms of the aliphatic hydrocarbon is substituted with a hydroxyl group, and is a compound that is liquid at normal temperature and normal pressure. The structure of the main chain constituting the aliphatic hydrocarbon may be a chain structure, may be a cyclic structure, may have a cyclic structure in the chain structure, The chain structure may contain an ether bond.
The “fluorine-based organic solvent” is a compound containing a fluorine atom and is a liquid at normal temperature and normal pressure.
The “ether-based organic solvent having no hydroxyl group” is a compound that has an ether bond (C—O—C) in its structure, does not have a hydroxyl group, and is liquid at normal temperature and pressure. The ether organic solvent having no hydroxyl group preferably further has no carbonyl group in addition to the hydroxyl group.

As the alcohol organic solvent, monohydric alcohols, dihydric alcohols, derivatives of dihydric alcohols, and the like are preferable.
As the monohydric alcohol, although depending on the number of carbon atoms, a primary or secondary monohydric alcohol is preferable, and a primary monohydric alcohol is most preferable.
Here, the monohydric alcohol means a compound in which one of the hydrogen atoms of a hydrocarbon compound composed only of carbon atoms and hydrogen atoms is substituted with a hydroxyl group, and does not include dihydric or higher polyhydric alcohol derivatives. . The hydrocarbon compound may have a chain structure or a cyclic structure.
The dihydric alcohol means a compound in which two hydrogen atoms of the hydrocarbon compound are substituted with a hydroxyl group, and does not include a trihydric or higher polyhydric alcohol derivative.
Examples of the dihydric alcohol derivative include compounds in which one of the hydroxyl groups of the dihydric alcohol is substituted with a substituent (such as an alkoxy group or an alkoxyalkyloxy group).

The boiling point (under normal pressure) of the alcohol-based organic solvent is preferably 80 to 250 ° C., more preferably 90 to 220 ° C., and preferably 100 to 200 ° C. from the viewpoint of solvent removal after purification. Particularly preferred.
Specific examples of the alcohol-based organic solvent include propylene glycol (PG); 1-butoxy-2-propanol (PGB), n-hexanol, 2-heptanol, 3-heptanol, and 1-heptanol as those having a chain structure. 5-methyl-1-hexanol, 6-methyl-2-heptanol, 1-octanol, 2-octanol, 3-octanol, 4-octanol, 2-ethyl-1-hexanol, 2- (2-butoxyethoxy) ethanol , N-pentyl alcohol, s-pentyl alcohol, t-pentyl alcohol, isopentyl alcohol, isobutanol (also referred to as isobutyl alcohol or 2-methyl-1-propanol, IBA), isopropyl alcohol, 2-ethylbutanol, neopentyl Alcoa , N- butanol, s- butanol, t-butanol, 1-propanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 4-methyl-2-pentanol (MIBC), and the like.
In addition, as those having a cyclic structure, cyclopentanemethanol, 1-cyclopentylethanol, cyclohexanol, cyclohexanemethanol (CM), cyclohexaneethanol, 1,2,3,6-tetrahydrobenzyl alcohol, exo-norbornol, 2-methyl Examples include cyclohexanol, cycloheptanol, 3,5-dimethylcyclohexanol, and benzyl alcohol.

  Among alcohol-based organic solvents, chain-structured monohydric alcohols or dihydric alcohol derivatives are preferred, such as 1-butoxy-2-propanol (PGB); isobutanol (also called isobutyl alcohol or 2-methyl-1-propanol). IBA.), 4-methyl-2-pentanol (MIBC) and n-butanol are preferred, and isobutanol (2-methyl-1-propanol) and 1-butoxy-2-propanol (PGB) are most preferred.

Examples of the fluorine-based organic solvent include fluorine atom-containing alcohol-based organic solvents such as C ₄ F ₉ CH ₂ CH ₂ OH, C ₃ F ₇ CH ₂ OH; CHF ₂ CF ₂ —CH ₂ —O—CF ₂ CHF ₂ , (C ₃ F ₇ ) (C ₂ F ₅ ) CH—O—CH _{3 and} other fluorine atom-containing ether organic solvents; CHF ₂ (CF ₂ ) ₆ C (═O) OCH ₃ , CHF ₂ (CF ₂ ) _And fluorine atom-containing alkyl ester solvents such as ₃ C (═O) OCH ₃ .

As an ether type organic solvent which does not have a hydroxyl group, the compound represented by the following general formula (s-1) is mentioned as a suitable thing, for example.
R ⁴⁰ —O—R ³⁰ (s-1)
[Wherein, R ⁴⁰ and R ³⁰ each independently represent a monovalent hydrocarbon group, and R ⁴⁰ and R ³⁰ may be bonded to form a ring. -O- represents an ether bond. ]

In the above formula, examples of the hydrocarbon group for R ⁴⁰ and R ³⁰ include an alkyl group and an aryl group, and an alkyl group is preferred. Among ^them, it is preferable that any of R ^{40, R 30} is an alkyl ^group, and ^{R 40} and ^{R 30} is more preferably the same alkyl group.
As each of the alkyl groups of R ^40, R ^30, not particularly limited, for example, straight, branched or cyclic alkyl group, and the like. In the alkyl group, part or all of the hydrogen atoms may or may not be substituted with a halogen atom or the like.
The alkyl group preferably has 1 to 15 carbon atoms, and more preferably 1 to 10 carbon atoms, for example, for easy control to a desired boiling point. Specific examples include an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a cyclopentyl group, and a hexyl group, and an n-butyl group and an isopentyl group are particularly preferable. .
The halogen atom that may be substituted for the hydrogen atom of the alkyl group is preferably a fluorine atom.
Each aryl group for R ⁴⁰ and R ³⁰ is not particularly limited, and is, for example, an aryl group having 6 to 12 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups, It may or may not be substituted with a halogen atom or the like.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specifically, a phenyl group, a benzyl group, a naphthyl group, etc. are mentioned, for example.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Is more preferable.
As the alkoxy group which may substitute the hydrogen atom of the said aryl group, a C1-C5 alkoxy group is preferable and a methoxy group and an ethoxy group are more preferable.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
In the above formula, R ⁴⁰ and R ³⁰ may be bonded to form a ring.
R ⁴⁰ and R ³⁰ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 10 carbon atoms), and the terminal of R ⁴⁰ is bonded to the terminal of R ^30. To form a ring. In addition, the carbon atom of the alkylene group may be substituted with an oxygen atom.
Specific examples of the ether organic solvent include 1,8-cineol, tetrahydrofuran, dioxane and the like.

  The boiling point (under normal pressure) of the ether-based organic solvent having no hydroxyl group is preferably 30 to 300 ° C, more preferably 100 to 200 ° C, and further preferably 140 to 180 ° C. By making the boiling point within the above range, purification can be easily performed. Moreover, the removal efficiency of the residual solvent after refinement | purification improves by being below an upper limit.

Specific examples of the ether organic solvent having no hydroxyl group include, for example, 1,8-cineol (boiling point 176 ° C.), dibutyl ether (boiling point 142 ° C.), diisopentyl ether (boiling point 171 ° C .; DIAE), dioxane (boiling point). 101 ° C), anisole (boiling point 155 ° C), ethyl benzyl ether (boiling point 189 ° C), diphenyl ether (boiling point 259 ° C), dibenzyl ether (boiling point 297 ° C), phenetole (boiling point 170 ° C), butylphenyl ether, tetrahydrofuran (boiling point) 66 ° C), ethyl propyl ether (boiling point 63 ° C), diisopropyl ether (boiling point 69 ° C), dihexyl ether (boiling point 226 ° C), dipropyl ether (boiling point 91 ° C), and the like.
The ether organic solvent having no hydroxyl group is preferably a cyclic or chain ether organic solvent, and is selected from the group consisting of 1,8-cineol, dibutyl ether and diisopentyl ether (DIAE). At least one of the above is preferred.

(W) component used for a washing | cleaning liquid may be single 1 type, and may use 2 or more types together.
The content of the component (W) in the cleaning liquid is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and may be 100% by mass.
When the content of the component (W) is equal to or higher than the lower limit, the resin (A1) can be purified well, and a resist pattern that is less susceptible to the second and subsequent patterning can be more easily formed.

The cleaning liquid may contain other components other than the component (W).
Examples of the other components include the organic solvent (S1).

The organic solvent (S1) is not particularly limited as long as it dissolves the resin (A1), and one or more kinds of organic solvents (S1) are conventionally appropriately selected from the known organic solvents for chemically amplified resist compositions. Can be used.
Suitable organic solvents (S1) that may be used in the cleaning liquid include, for example, lactones such as γ-butyrolactone; acetone, methyl ethyl ketone, cyclohexanone (CH), methyl n-pentyl ketone, methyl isopentyl ketone, 2-heptanone. Ketones such as: Polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol; Compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate or dipropylene glycol monoacetate , Monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether of the polyhydric alcohol or the compound having an ester bond, etc. Derivatives of polyhydric alcohols such as compounds having an ether bond such as monoalkyl ether or monophenyl ether, among which propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred]; methyl lactate Esters such as ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, Aromatic organic solvents such as xylene, cymene, and mesitylene are listed.
Among the above, derivatives of polyhydric alcohols such as ketones and compounds having an ether bond are particularly preferable.
In the cleaning liquid, the organic solvent (S1) may be used alone or in combination of two or more.

Examples of the method (purification method) for washing the resin (A1) with the washing liquid include the following methods.
Purification method (1): A method in which a resin (A1) solution in which a resin (A1) is dissolved in an organic solvent (S1) is mixed with a cleaning liquid consisting only of the organic solvent (W).
Purification method (2): A method in which the resin (A1) solution is mixed with a cleaning liquid composed of a mixed solvent of an organic solvent (W) and an organic solvent (S1).
Purification method (3): A method in which the resin (A1) is directly mixed with a mixed solvent of the organic solvent (W) and the organic solvent (S1).

[Purification method (1)]
As organic solvent (S1), since solubility of resin (A1) is high, ketones are preferable and methyl ethyl ketone is especially preferable.
In the resin (A1) solution, the content of the resin (A1) is preferably 50% by mass or less, more preferably 45% by mass or less, and further preferably 15 to 40% by mass from the viewpoint of polymer solubility.
The method of mixing the resin (A1) solution with the cleaning liquid is not particularly limited, and examples thereof include a method of dropping the resin (A1) solution into the cleaning liquid (organic solvent (W)).
As for the temperature conditions at the time of mixing, 0-60 degreeC is preferable, 10-50 degreeC is more preferable, and 15-40 degreeC is further more preferable.
The mixing ratio of the resin (A1) solution and the cleaning liquid is preferably 1 to 30 parts by mass, more preferably 1 to 20 parts by mass of the resin (A1) with respect to 100 parts by mass of the cleaning liquid. More preferably, it is 15 parts by mass.
By setting the ratio of the resin (A1) within the above range, the yield and the degree of purification can be further optimized.
In the purification method (1), a white precipitate is obtained by mixing the resin (A1) solution with a washing liquid (only the organic solvent (W)), and the white precipitate is filtered off by filtration and dried. Thus, a purified product of the resin (A1) is prepared.

[Purification method (2)]
The purification method (2) is the same as the purification method (1) except that the cleaning liquid consisting only of the organic solvent (W) is changed to a cleaning liquid consisting of a mixed solvent of the organic solvent (W) and the organic solvent (S1). It is.
As the organic solvent (S1) in the cleaning liquid, it can be easily used for the first resist material and is expected to increase the resistance to the second resist material. Derivatives of polyhydric alcohols are preferred, and PGMEA is particularly preferred.
In the mixed solvent, the mixing ratio of the organic solvent (W) and the organic solvent (S1) is a mass ratio represented by (W) / (S1), and (W) / (S1) = 99 / 1-60 / 40 is preferable, 99/1 to 70/30 is more preferable, and 95/5 to 80/20 is further more preferable.
By making the mass ratio represented by (W) / (S1) within the above range, the yield and the degree of purification can be further optimized.
In the purification method (2), a white precipitate is obtained by mixing the resin (A1) solution with a cleaning liquid (a mixed solvent of an organic solvent (W) and an organic solvent (S1)), and the white precipitate is filtered. A purified product of the resin (A1) is prepared by filtering and drying by treatment.

[Purification method (3)]
The time for directly mixing the resin (A1) with the mixed solvent is preferably 1 to 120 minutes, more preferably 15 to 90 minutes, and even more preferably 30 to 60 minutes.
As for the temperature conditions at the time of mixing, 0-60 degreeC is preferable, 10-50 degreeC is more preferable, and 15-40 degreeC is further more preferable.
The mixing ratio of the resin (A1) and the cleaning liquid is preferably 1 to 30 parts by mass, more preferably 1 to 20 parts by mass, and more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the cleaning liquid. More preferably, it is part by mass.
By setting the ratio of the resin (A1) within the above range, the yield and the degree of purification can be further optimized.
In the mixed solvent, the mixing ratio of the organic solvent (W) and the organic solvent (S1) is a mass ratio represented by (W) / (S1), and (W) / (S1) = 99 / 1-60 / 40 is preferable, 99/1 to 70/30 is more preferable, and 95/5 to 80/20 is further more preferable.
By making the mass ratio represented by (W) / (S1) within the above range, the yield and the degree of purification can be further optimized.
The organic solvent (S1) in the cleaning liquid is preferably a derivative of a polyhydric alcohol such as a ketone or a compound having an ether bond, and particularly preferably methyl ethyl ketone or PGMEA because the degree of purification is improved. In addition, since the degree of purification of the organic solvent (S1) is further improved, it is also preferable to use ketones and a derivative of a polyhydric alcohol such as a compound having an ether bond in combination. The ratio is preferably (ketones) / (derivative of polyhydric alcohol) = 1/99 to 99/1, more preferably 10/90 to 90/10, 20/80 to 80 / More preferably, it is 20.
In the purification method (3), a resin (A1) is directly mixed with a mixed solvent to obtain a white dispersion. The white dispersion is filtered off by filtration and dried to obtain a resin (A1). A refined product is prepared.

In the purification methods (1) to (3) described above, since the resin (A1) can be more uniformly washed and a resist pattern that is less likely to cause film loss can be easily formed, the purification methods (1) and (2) are preferable.
Moreover, since there is no process of preparing a resin (A1) solution and it is a simple method, the purification method (3) is preferable.
In the present invention, the purified product of the resin (A1) treated by the method (purification method) of washing the resin (A1) with the washing liquid is blended with the first resist material.

[Patterning process (1)]
The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC) and a lower layer film in a multilayer resist method. In particular, it is preferable to provide an organic film because a pattern with a high aspect ratio can be formed on the substrate, which is useful in manufacturing semiconductors.
Here, the multilayer resist method is a method in which at least one organic film (lower film) and at least one resist film are provided on a substrate, and the lower layer is patterned using the resist pattern formed on the upper resist film as a mask. It is said that a high aspect ratio pattern can be formed. In the multilayer resist method, basically, a method having a two-layer structure of an upper layer resist film and a lower layer film, and one or more intermediate layers (metal thin film, etc.) are provided between these resist film and lower layer film. It is divided into a method of providing a multilayer structure of three or more layers provided. According to the multilayer resist method, by securing a required thickness with the lower layer film, the resist film can be thinned and a fine pattern with a high aspect ratio can be formed.
The inorganic film can be formed, for example, by applying an inorganic antireflective film composition such as a silicon-based material on a substrate and baking it.
The organic film is formed by, for example, applying an organic film forming material in which a resin component or the like constituting the film is dissolved in an organic solvent on a substrate with a spinner or the like, preferably 200 to 300 ° C., preferably 30 to 300 seconds. More preferably, it can be formed by baking under heating conditions of 60 to 180 seconds.

The method of forming the first resist film by applying the first resist material on the support using the first resist material containing the resin (A1) purified by the purification method described above is particularly limited. Instead, a conventionally known method can be used.
Specifically, for example, a chemically amplified resist composition or the like as a first resist material is applied onto a support by a conventionally known method using a spinner or the like, and is baked at a temperature of 80 to 150 ° C. Pre-baking) is performed for 40 to 120 seconds, preferably 60 to 90 seconds, and the first resist film can be formed by volatilizing the organic solvent.
The thickness of the first resist film is preferably 30 to 500 nm, more preferably 40 to 400 nm, and still more preferably 50 to 200 nm. By setting it within this range, there are effects that a resist pattern can be formed with high resolution and sufficient resistance to etching can be obtained.

Next, the first resist film is selectively exposed and alkali developed to form a first resist pattern.
Specifically, for example, the first resist film formed as described above is selectively exposed through a photomask, preferably subjected to a post-exposure heating (PEB) treatment, and alkali-developed to form a first resist film. A resist pattern is formed.

The wavelength used for the exposure is not particularly limited, and includes KrF excimer laser, ArF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be done using radiation.
As the photomask, for example, a binary mask (Binary-Mask) in which the transmittance of the light shielding portion is 0% or a halftone phase shift mask (HT-Mask) in which the transmittance of the light shielding portion is 6% can be used.
In general, the binary mask is formed by forming a chromium film, a chromium oxide film or the like as a light shielding portion on a quartz glass substrate.
As the halftone phase shift mask, generally, a quartz glass substrate on which a MoSi (molybdenum silicide) film, a chromium film, a chromium oxide film, a silicon oxynitride film, or the like is formed as a light shielding portion is used. .
Note that selective exposure may be performed by exposure without using a photomask, for example, drawing by EB or the like.

The selective exposure of the first resist film may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or immersion exposure.
In immersion exposure, as described above, the portion between the lens, which has been conventionally filled with an inert gas such as air or nitrogen, and the resist film on the wafer is refracted larger than the refractive index of air. Exposure is performed in a state filled with a solvent (immersion medium) having a high rate.
More specifically, the immersion exposure is a solvent (immersion medium) having a refractive index larger than the refractive index of air between the resist film obtained as described above and the lowermost lens of the exposure apparatus. And in that state, exposure (immersion exposure) is performed through a desired photomask.
As the immersion medium, a solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the first resist film exposed by the immersion exposure is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorine-based inert liquid include a fluorine-based compound such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as a main component. Examples thereof include liquids, and those having a boiling point of 70 to 180 ° C are preferable, and those having a boiling point of 80 to 160 ° C are more preferable. It is preferable that the fluorine-based inert liquid has a boiling point in the above range since the medium used for immersion can be removed by a simple method after the exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound.
More specifically, examples of the perfluoroalkyl ether compound include perfluoro (2-butyl-tetrahydrofuran) (boiling point: 102 ° C.). Examples of the perfluoroalkylamine compound include perfluorotributylamine ( Boiling point of 174 ° C.).
As the immersion medium, water is preferably used from the viewpoints of cost, safety, environmental problems, versatility, and the like.

The PEB treatment is performed at a baking temperature that can change (increase / decrease) the solubility of the first resist film in an alkaline developer.
That is, the first resist film, for example, a resist film formed using a chemically amplified resist composition or the like, is subjected to PEB treatment after exposure within the resist film of the acid generated from the acid generator. And the change (increase / decrease) in the solubility of the resist film in the alkaline developer by the action of the acid proceeds.
Specifically, for example, after selectively exposing the first resist film through a photomask having a predetermined pattern formed, PEB treatment is performed for 40 to 120 seconds under a temperature condition of 80 to 150 ° C., preferably It is applied for 60 to 90 seconds.

After the PEB treatment, alkali development is performed to form a first resist pattern.
The alkali development can be carried out by a known method using an aqueous alkali solution, for example, an aqueous tetramethylammonium hydroxide (TMAH) solution having a concentration of 0.1 to 10% by mass. By such alkali development, the exposed portion (when using a positive resist composition) or the unexposed portion (when using a negative resist composition) of the first resist film is removed to form a first resist pattern. Is done.
After the alkali development, a rinse treatment with water or the like may be performed.
Further, after the alkali development, a baking process (post-bake) may be further performed. Post-baking is usually performed under conditions of about 100 ° C. (because it is performed for the purpose of removing water after alkali development and rinsing), and the processing time is preferably 30 to 90 seconds.

[Patterning process (2)]
Next, a second resist material is applied on the support on which the first resist pattern is formed to form a second resist film.
For example, when the first resist pattern is a line-and-space resist pattern (hereinafter referred to as “L / S pattern”), the first resist pattern is filled with a space portion between a plurality of resist patterns in the L / S pattern. Similar to the first resist film, the second resist film can be formed by a conventionally known method.
The film thickness of the second resist film is preferably at least the same as or higher than the height of the first resist pattern. That is, when the support is viewed from the second resist film side, the surface is preferably flat.

Next, the second resist film is selectively exposed and alkali developed to form a resist pattern.
Specifically, for example, the second resist film is selectively exposed through a photomask at a position different from the position where the plurality of resist patterns are formed, subjected to PEB treatment, and subjected to alkali development to form a resist. Form a pattern.
As a result, when the second resist material is positive, the exposed portion of the second resist film is removed, and when the second resist material is negative, the unexposed portion is removed. In the L / S pattern, a plurality of resists are removed. A plurality of resist patterns are newly formed between the patterns. As a result, a resist pattern including a plurality of resist patterns and a plurality of resist patterns newly formed on the second resist film is formed on the support.
Here, in the present invention, except for the case where it completely coincides with the first resist pattern, all are “positions different from the position where the first resist pattern is formed”, and there are no overlaps and some Including duplicate cases.
In the present invention, for example, when the L / S pattern is finally formed, it is preferable that the position where the first resist pattern is formed and the position selectively exposed in the patterning step (2) do not overlap at all. . Thereby, it is possible to form a narrow pitch pattern in which the pattern interval (pitch) is narrower than the first resist pattern formed in the patterning step (1).

The selective exposure of the second resist film can be performed, for example, by slightly shifting the exposure position of the photomask used in the patterning step (1). At this time, a photomask different from the photomask used in the patterning step (1) may be used.
The position of the resist pattern formed from the second resist film may not overlap at all with the position of the first resist pattern, and may partially overlap with the position of the first resist pattern. It is preferable that the position of the resist pattern formed from the second resist film and the position of the first resist pattern do not overlap at all. Thus, a narrow pitch resist pattern having a pattern interval (pitch) narrower than that of the first resist pattern formed in the patterning step (1) is obtained.

For example, in the case of forming an L / S pattern, for example, in the patterning step (1), after forming an L / S pattern using a line and space photomask in which a plurality of lines are arranged at a constant pitch In the patterning step (2), the position of the photomask is changed, and a line pattern is formed at an intermediate position between the line pattern and the line pattern formed in the patterning step (1). An L / S pattern (dense pattern) having a narrower pitch than the S pattern (sparse pattern) is formed.
As the “sparse pattern”, in the L / S pattern, an L / S pattern having a wider space width than line width: space width = 1: 2 is preferable.

After exposure, PEB processing is performed.
The PEB process can be performed by the same method as the PEB process in the patterning step (1).
After the PEB treatment, alkali development of the second resist film is performed. The alkali development can be carried out by a known method using an aqueous alkali solution, for example, an aqueous tetramethylammonium hydroxide (TMAH) solution having a concentration of 0.1 to 10% by mass. By such alkali development, when the second resist material is a positive type, an exposed portion of the second resist film is removed, and when it is a negative type, an unexposed portion is removed to form a resist pattern.
After the alkali development, a rinse treatment with water or the like may be performed.
Further, after the alkali development, a baking process (post-bake) may be further performed. Post-baking is usually performed under conditions of about 100 ° C. (because it is performed for the purpose of removing water after alkali development and rinsing), and the processing time is preferably 30 to 90 seconds.

In the resist pattern forming method of the present invention, it is preferable that the first resist pattern is an L / S pattern because a dense L / S pattern with a narrow pitch can be easily formed.
Specifically, for example, after forming an L / S pattern (sparse pattern) having a line width of 100 nm and a line width: space width = 1: 3, the photomask is translated by 200 nm in a direction perpendicular to the line direction. Then, an L / S pattern having a line width of 100 nm and a line width: space width = 1: 3 is formed. As a result, an L / S pattern (dense pattern) having a line width of 100 nm and a line width: space width = 1: 1 can be formed.

  Further, the photomask used in the patterning step (1) is rotated or moved, or a photomask different from the photomask used in the patterning step (1) (for example, a line-and-space photomask or patterning in the patterning step (1)). By using a hole photomask or the like in step (2), a fine resist pattern and / or resist patterns having various shapes can be formed.

For example, a hole-like or lattice-like resist pattern is formed by exposing and developing in a crossing relationship with the first L / S pattern obtained in the patterning step (1), that is, by performing cross-line patterning. You can also When performing cross-line patterning, the ratio of line width: space width and the crossing angle of each pattern in each line-and-space resist pattern match the shape of the finally obtained hole-shaped or lattice-shaped resist pattern. It may be appropriately controlled. For example, the intersecting angle may be made orthogonal or obliquely (less than 90 °) depending on the target pattern.
Thus, the formation of a hole-like (or lattice-like) pattern from the first and second L / S patterns occurs due to exposure during the formation of the second resist pattern in addition to the process factors. This is considered to be due to non-uniformity in the acid diffusion direction (for example, in the direction where the first L / S pattern exists, acid diffusion can be controlled (compared to the direction where the first L / S pattern does not exist)).

In the resist pattern forming method of the present invention, after the patterning step (2), the same operation as the above-described patterning step (2) may be repeated a plurality of times. That is, a third resist material is applied on the support on which the resist pattern has been formed in the patterning step (2) to form a resist film, the resist film is selectively exposed, and alkali-developed to form a resist. You may perform the operation which forms a pattern in multiple times. Thereby, a denser pattern with a narrower pitch or a pattern with a complicated shape can be formed.
In such a case, the resin (A1) washed (purified) with both the organic solvent (S2) compounded in the second resist material and the organic solvent (S3) compounded in the third resist material is used as the first resist. While blended with the material, it is preferable to blend the resin (A2) washed (purified) with the organic solvent (S3) blended with the third resist material into the second resist material. Accordingly, it is possible to form the first resist pattern that is not easily influenced by the second and third patterning and the second resist pattern that is not easily influenced by the third patterning.

In the resist pattern forming method of the present invention, after the patterning step (2), the support may be etched using the formed resist pattern as a mask. Thus, a semiconductor device etc. can be manufactured by etching a support body.
As the etching method, a known dry or wet etching method can be used. For example, the etching of the organic film (resist pattern, organic antireflection film, etc.) is preferably dry etching. In particular, oxygen plasma etching or etching using CF ₄ gas or CHF ₃ gas is preferable, and oxygen plasma etching is particularly preferable.
Etching of the substrate and the inorganic antireflection film is preferably performed using a halogen gas, more preferably using a fluorocarbon gas, and particularly preferably using a CF ₄ gas or a CHF ₃ gas.

(First resist material)
The first resist material contains a resin (A1) and an organic solvent (S1) that dissolves the resin (A1) (hereinafter also referred to as “component (S1)”), and is dissolved in an alkaline developer by exposure. Sex changes.
The first resist material is preferably a chemically amplified resist composition containing an acid generator that generates an acid upon exposure. Specifically, the resin (A1) (hereinafter referred to as “component (A1)”). A resin whose solubility in an alkaline developer is changed by the action of an acid generated from the acid generator, an organic solvent (S1) (component (S1)) that dissolves the component (A1), and What contains an acid generator (B) (henceforth "(B) component") is mentioned as a suitable thing.
When the resist film formed using the first resist material on the support is selectively exposed during the formation of the resist pattern, an acid is generated from the component (B), and the acid is a component of the component (A1). Change the solubility in an alkaline developer. As a result, while the solubility of the exposed portion of the resist film in the alkali developer changes, the solubility of the unexposed portion in the alkali developer does not change. However, in the case of the negative type, the unexposed portion is dissolved and removed to form a resist pattern.
The first resist material may be a negative resist composition or a positive resist composition.

<(A1) component>
The component (A1) is a polymer compound that dissolves in the organic solvent (S1) and does not dissolve in the organic solvent (S2), and has been used as a base material component for chemically amplified resists so far. (Resin) can be used alone or in admixture of two or more.
The “base material component” here is an organic compound having a film forming ability, and an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved and a nano-level resist pattern is easily formed.
“Organic compounds having a molecular weight of 500 or more” used as the base component are roughly classified into non-polymers and polymers.
As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, a nonpolymer having a molecular weight of 500 or more and less than 4000 is referred to as a low molecular compound.
As the polymer, those having a molecular weight of 1000 or more are usually used. Hereinafter, a polymer having a molecular weight of 1000 or more is referred to as a polymer compound. In the case of a polymer compound, the “molecular weight” is a polystyrene-reduced mass average molecular weight measured by GPC (gel permeation chromatography). Hereinafter, the polymer compound may be simply referred to as “resin”.
In the present invention, the component (A1) is preferably an acrylic resin.

When the first resist material in the present invention is a “positive chemically amplified resist composition”, the component (A1) is a resin (hereinafter referred to as “(A1-)” whose solubility in an alkaline developer is increased by the action of an acid. 1) Component ")) is used.
The component (A1-1) is hardly soluble in an alkali developer before exposure, and when an acid is generated from the component (B) by exposure, the solubility in the alkali developer is increased by the action of the acid. . Therefore, in the formation of the resist pattern, when the resist film obtained by applying the positive chemically amplified resist composition on the support is selectively exposed, the exposed portion is hardly soluble in an alkali developer. However, since the unexposed area remains hardly soluble in alkali and does not change, a resist pattern can be formed by alkali development.

The component (A1) in the first resist material is preferably a resin ((A1-1) component) whose solubility in an alkaline developer is increased by the action of an acid. That is, the first resist material in the present invention is preferably a positive chemically amplified resist composition.
When the first resist material is a “positive chemically amplified resist composition”, as a base material component, in addition to the component (A1-1), the solubility in an alkaline developer is increased due to the action of an acid. Molecular compound components may be used.

[(A1-1) component]
As the component (A1-1), a resin component (base resin) that is usually used as a base component for a chemically amplified resist can be used singly or in combination of two or more. .
As the component (A1-1), those having a structural unit derived from an acrylate ester are preferable.

Here, in the present specification and claims, the “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include those in which a hydrogen atom is bonded to the carbon atom at the α-position, and those in which a substituent (atom or group other than a hydrogen atom) is bonded to the carbon atom in the α-position. Include concepts. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms and a halogenated alkyl group having 1 to 5 carbon atoms.
Note that the α-position (α-position carbon atom) of a structural unit derived from an acrylate ester means a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
In the acrylic ester, the alkyl group having 1 to 5 carbon atoms as the substituent at the α-position, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl And a lower linear or branched alkyl group such as a group, a pentyl group, an isopentyl group and a neopentyl group.
Further, as the halogenated alkyl group having 1 to 5 carbon atoms, specifically, a part or all of the hydrogen atoms in the above-mentioned “alkyl group having 1 to 5 carbon atoms as a substituent at the α-position” are substituted with halogen atoms. Group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
In the present invention, the α-position of the acrylate ester is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. It is more preferably a C 1-5 alkyl group or a C 1-5 fluorinated alkyl group, and most preferably a hydrogen atom or a methyl group in terms of industrial availability.

Especially, it is preferable as (A1-1) component to have a structural unit (a1) induced | guided | derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
In addition to the structural unit (a1), the component (A1-1) preferably further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.
In addition to the structural unit (a1) or the structural unit (a1) and the structural unit (a2), the component (A1-1) is further an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. It is preferable to have a structural unit (a3) derived from
In addition to the structural unit (a1), the component (A1-1) is added to the structural unit (a1) and the structural unit (a3), in addition to the structural unit (a1) and the structural unit (a2), or In addition to the structural units (a1) to (a3), other structural units may be included.

(Structural unit (a1))
The structural unit (a1) is a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire component (A1-1) difficult to dissolve in an alkali developer before dissociation, and dissociates with an acid. A1-1) This increases the solubility of the entire component in an alkaline developer, and those proposed so far as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists can be used. . In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. .

Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (═O ) -O-) shows a structure in which the tertiary carbon atom of the chain-like or cyclic alkyl group is bonded to the terminal oxygen atom. In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.

Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.
Here, the term “aliphatic branched” in the claims and the specification means having a branched structure having no aromaticity.
The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group.
The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
As the aliphatic branched acid dissociable, dissolution inhibiting group, a tertiary alkyl group having 4 to 8 carbon atoms is preferable, and specific examples include a tert-butyl group, a tert-pentyl group, and a tert-heptyl group. .

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a lower alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O) and the like.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group.
The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated. The “aliphatic cyclic group” is preferably a polycyclic group.
Examples of the aliphatic cyclic group include a monocycloalkane which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group; bicycloalkane, tricycloalkane, tetracycloalkane. And groups obtained by removing one or more hydrogen atoms from a polycycloalkane. More specifically, monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane are exemplified. .

  Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include a group having a tertiary carbon atom on the ring skeleton of a cyclic alkyl group. Specifically, 2-methyl-2 -Adamantyl group, 2-ethyl-2-adamantyl group, etc. are mentioned. Alternatively, in the structural units represented by the following general formulas (a1 ″ -1) to (a1 ″ -6), an adamantyl group such as a group bonded to an oxygen atom of a carbonyloxy group (—C (O) —O—) A group having an aliphatic cyclic group such as a cyclohexyl group, a cyclopentyl group, a norbornyl group, a tricyclodecyl group, or a tetracyclododecyl group and a branched alkylene group having a tertiary carbon atom bonded thereto. Can be mentioned.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｒ^１５、Ｒ^１６はアルキル基（直鎖状、分岐鎖状のいずれでもよく、好ましくは炭素数１〜５である）を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; R ¹⁵ and R ^{16 each} represents an alkyl group (which may be linear or branched, and preferably has 1 to 5 carbon atoms. Is). ]

  In the general formulas (a1 ″ -1) to (a1 ″ -6), the lower alkyl group or halogenated lower alkyl group of R is a lower alkyl group or halogenated lower alkyl which may be bonded to the α-position of the acrylate ester. It is the same as the alkyl group.

The “acetal-type acid dissociable, dissolution inhibiting group” is generally bonded to an oxygen atom by substituting a hydrogen atom at the terminal of an alkali-soluble group such as a carboxy group or a hydroxyl group. When an acid is generated by exposure, the acid acts to break the bond between the acetal acid dissociable, dissolution inhibiting group and the oxygen atom to which the acetal acid dissociable, dissolution inhibiting group is bonded.
Examples of the acetal type acid dissociable, dissolution inhibiting group include a group represented by the following general formula (p1).

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または低級アルキル基を表し、ｎは０〜３の整数を表し、Ｙは低級アルキル基または脂肪族環式基を表す。］

[Wherein, R ¹ ′ and R ² ′ each independently represents a hydrogen atom or a lower alkyl group, n represents an integer of 0 to 3, and Y represents a lower alkyl group or an aliphatic cyclic group. ]

In the above formula, n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the lower alkyl group for R ¹ ′ and R ² ′ include the same lower alkyl groups as those described above for R. A methyl group or an ethyl group is preferable, and a methyl group is most preferable.
Of these, at least one of R ¹ ′ and R ² ′ is preferably a hydrogen atom. That is, the acid dissociable, dissolution inhibiting group (p1) is preferably a group represented by the following general formula (p1-1).

［式中、Ｒ^１’、ｎ、Ｙは上記と同様である。］

[Wherein R ¹ ′, n and Y are the same as described above. ]

Examples of the lower alkyl group for Y include the same lower alkyl groups as those described above for R.
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups that have been proposed in a number of conventional ArF resists. For example, the above “aliphatic ring” Examples thereof are the same as those in the formula group.

  Examples of the acetal type acid dissociable, dissolution inhibiting group also include a group represented by the following general formula (p2).

［式中、Ｒ^１７、Ｒ^１８はそれぞれ独立して直鎖状または分岐鎖状のアルキル基または水素原子であり、Ｒ^１９は直鎖状、分岐鎖状または環状のアルキル基である。または、Ｒ^１７およびＲ^１９がそれぞれ独立に直鎖状または分岐鎖状のアルキレン基であって、Ｒ^１７の末端とＲ^１９の末端とが結合して環を形成していてもよい。］

[Wherein, R ¹⁷ and R ¹⁸ each independently represent a linear or branched alkyl group or a hydrogen atom, and R ¹⁹ represents a linear, branched or cyclic alkyl group. Alternatively, R ¹⁷ and R ¹⁹ may be each independently a linear or branched alkylene group, and the end of R ^{17 and} the end of R ¹⁹ may be bonded to form a ring. ]

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group. In particular, it is preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a monocycloalkane which may or may not be substituted with a fluorine atom or a fluorinated alkyl group; one or more polycycloalkanes such as bicycloalkane, tricycloalkane and tetracycloalkane. Examples include a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula, R ¹⁷ and R ¹⁹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon atoms), and the end of R ^{19 and} the end of R ¹⁷ And may be combined.
In this case, a cyclic group is formed by R ¹⁷ , R ¹⁹ , the oxygen atom to which R ¹⁹ is bonded, and the carbon atom to which the oxygen atom and R ¹⁷ are bonded. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  As the structural unit (a1), one or more selected from the group consisting of structural units represented by the following general formula (a1-0-1) and structural units represented by the following general formula (a1-0-2): Is preferably used.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^１は酸解離性溶解抑制基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; and X ¹ represents an acid dissociable, dissolution inhibiting group. ]

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^２は酸解離性溶解抑制基を示し；Ｙ^２は２価の連結基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; X ² represents an acid dissociable, dissolution inhibiting group; Y ² represents a divalent linking group. ]

In general formula (a1-0-1), the lower alkyl group or halogenated lower alkyl group for R is the same as the lower alkyl group or halogenated lower alkyl group that may be bonded to the α-position of the acrylate ester. .
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. And tertiary alkyl ester type acid dissociable, dissolution inhibiting groups are preferred.

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).

Examples of the divalent linking group for Y ² include an alkylene group, a divalent aliphatic cyclic group, and a divalent linking group containing a hetero atom.
As the aliphatic cyclic group, those similar to the explanation of the “aliphatic cyclic group” can be used except that a group in which two or more hydrogen atoms are removed is used.
When Y ² is an alkylene group, it is preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and 1 to 3 carbon atoms. Most preferably it is.
When Y ² is a divalent aliphatic cyclic group, a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane, or tetracyclododecane is particularly preferable. .
When Y ² is a divalent linking group containing a hetero atom, examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O—, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group or an acyl group), —S—. , —S (═O) ₂ —, —S (═O) ₂ —O—, “—AO (oxygen atom) —B— (wherein A and B each independently have a substituent) A divalent hydrocarbon group that may be present.) ”And the like.

When Y ² is —NH—, the substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. It is particularly preferred that
When Y ² is “A—O—B”, A and B are each independently a divalent hydrocarbon group which may have a substituent.
The hydrocarbon group having “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.

  The hydrocarbon group in A may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.

The aliphatic hydrocarbon group for A may be saturated or unsaturated, and is usually preferably saturated.
Specific examples of the aliphatic hydrocarbon group for A include a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in the structure.

The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 2 to 5, and most preferably 2.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group, an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [— (CH ₂ ) ₃ -], tetramethylene group _{[- (CH 2) 4 -} ], a pentamethylene group _{[- (CH 2) 5 -} ] , and the like.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ). _{2 -, - C (CH 3} ) (CH 2 CH 3) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as - Alkylethylene groups such as CH (CH ₃ ) CH ₂ —, —CH (CH ₃ ) CH (CH ₃ ) —, —C (CH ₃ ) ₂ CH ₂ —, —CH (CH ₂ CH ₃ ) CH ₂ —; Alkyl trimethylene groups such as —CH (CH ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) CH ₂ —; —CH (CH ₃ ) CH ₂ CH ₂ CH ₂ —, —CH ₂ CH (CH _{3) CH} 2 CH ₂ - alkyl, such as alkyl tetramethylene group such as Such as an alkylene group, and the like. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (═O).

Examples of the aliphatic hydrocarbon group containing a ring include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and the cyclic aliphatic hydrocarbon group described above as a chain-like aliphatic group. And a group bonded to the terminal of the aromatic hydrocarbon group or interposed in the middle of the chain-like aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms have been removed from a monocycloalkane having 3 to 6 carbon atoms is preferable, and examples of the monocycloalkane include cyclopentane and cyclohexane.
As the polycyclic group, a group in which two hydrogen atoms have been removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, tetra And cyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.

  A is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 2 to 5 carbon atoms, and most preferably an ethylene group.

Examples of the aromatic hydrocarbon group in A include a monovalent aromatic hydrocarbon group such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. A divalent aromatic hydrocarbon group obtained by further removing one hydrogen atom from the nucleus of the aromatic hydrocarbon; a part of carbon atoms constituting the ring of the divalent aromatic hydrocarbon group is an oxygen atom, a sulfur atom, Aromatic hydrocarbon groups substituted with heteroatoms such as nitrogen atoms; arylalkyl groups such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl, 2-naphthylethyl and the like And an aromatic hydrocarbon group obtained by removing one hydrogen atom from the nucleus of the aromatic hydrocarbon.
The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the hydrocarbon group for B include the same divalent hydrocarbon groups as those described above for A.
B is preferably a linear or branched aliphatic hydrocarbon group, particularly preferably a methylene group or an alkylmethylene group.
The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

  More specifically, examples of the structural unit (a1) include structural units represented by the following general formulas (a1-1) to (a1-4).

［式中、Ｘ’は第３級アルキルエステル型酸解離性溶解抑制基を表し、Ｙは炭素数１〜５の低級アルキル基、または脂肪族環式基を表し；ｎは０〜３の整数を表し；Ｙ^２は２価の連結基を表し；Ｒは前記と同じであり、Ｒ^１’、Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５の低級アルキル基を表す。］

[Wherein, X ′ represents a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, Y represents a lower alkyl group having 1 to 5 carbon atoms, or an aliphatic cyclic group; n represents an integer of 0 to 3] Y ² represents a divalent linking group; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. ]

In the formula, X 'include the same tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups as those described above for X ^{1.
R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable, dissolution inhibiting group" described above ^{(p1) ', R 2'} , n, Y The same thing is mentioned.
The Y ^2, the same groups as those described above for ^{Y 2} in the general formula (a1-0-2).

Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
Among these, the structural unit represented by the general formula (a1-1) or (a1-3) is preferable, and specifically, the formulas (a1-1-1) to (a1-1-4) and the formula (a1) -1-16) to (a1-1-17), formulas (a1-1-20) to (a1-1-23), formula (a1-1-26), formulas (a1-1-32) to ( It is more preferable to use at least one selected from the group consisting of a1-1-33) and formulas (a1-3-25) to (a1-3-28).
Furthermore, as the structural unit (a1), in particular, the following general formula (a1-1-1-) which includes structural units of the formulas (a1-1-1) to (a1-1-3) and the formula (a1-1-26) 01); formulas (a1-1-16) to (a1-1-17), formulas (a1-1-20) to (a1-1-23) and formula (a1-1-32) Represented by the following general formula (a1-1-02) including structural units of (a1-1-33); structural units of formulas (a1-3-25) to (a1-3-26) What is represented by the following general formula (a1-3-01), or the following general formula (a1-3-02) that includes structural units of the formulas (a1-3-27) to (a1-3-28) ) Is also preferred.

（式中、Ｒは水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基を示し、Ｒ^１１は炭素数１〜５のアルキル基を示す。）

(In the formula, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ¹¹ represents an alkyl group having 1 to 5 carbon atoms.)

（式中、Ｒは水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基を示し、Ｒ^１２は炭素数１〜５のアルキル基を示す。ｎ’は１〜６の整数を表す。）

(In the formula, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, R ¹² represents an alkyl group having 1 to 5 carbon atoms. Represents an integer of 6.)

In general formula (a1-1-01), R is the same as defined above.
Alkyl group of 1 to 5 carbon atoms for R ¹¹ is the same as the alkyl group having 1 to 5 carbon atoms for R, a methyl group or an ethyl group is preferred.

In general formula (a1-1-02), R is the same as defined above.
The alkyl group having 1 to 5 carbon atoms of R ¹² is the same as the alkyl group having 1 to 5 carbon atoms in R, preferably a methyl group or an ethyl group, and most preferably an ethyl group.
n ′ is preferably 1 or 2.

（式中、Ｒは水素原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基を示し；Ｒ^１４は炭素数１〜５のアルキル基であり、Ｒ^１３は水素原子またはメチル基であり、ａ０は１〜１０の整数である。）

(In the formula, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; R ¹⁴ represents an alkyl group having 1 to 5 carbon atoms, and R ¹³ represents hydrogen. An atom or a methyl group, and a0 is an integer of 1 to 10.)

（式中、Ｒは水素原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基を示し；Ｒ^１４は炭素数１〜５のアルキル基であり、Ｒ^１３は水素原子またはメチル基であり、ａ０は１〜１０の整数であり、ｎ’は１〜６の整数である。）

(In the formula, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; R ¹⁴ represents an alkyl group having 1 to 5 carbon atoms, and R ¹³ represents hydrogen. An atom or a methyl group, a0 is an integer of 1 to 10, and n ′ is an integer of 1 to 6.)

In the general formula (a1-3-01) or (a1-3-02), R is the same as described above.
R ¹³ is preferably a hydrogen atom.
Alkyl group of 1 to 5 carbon atoms for R ¹⁴ is the same as the alkyl group having 1 to 5 carbon atoms for R, a methyl group or an ethyl group is preferred.
a0 is preferably an integer of 1 to 8, particularly preferably an integer of 2 to 5, and most preferably 2.
n ′ is the same as above, and is preferably 1 or 2.

  In the component (A1-1), the proportion of the structural unit (a1) is preferably 10 to 80 mol%, more preferably 20 to 70 mol%, based on the total of all structural units constituting the component (A1-1). More preferably, it is 25-60 mol%. By setting it to the lower limit value or more, a pattern can be easily obtained when the resist composition is used, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

(Structural unit (a2))
The structural unit (a2) is a structural unit derived from an acrylate ester containing a lactone-containing cyclic group.
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing a —O—C (═O) — structure. The lactone ring is counted as the first ring, and when it is only the lactone ring, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure.
The lactone cyclic group of the structural unit (a2) has an affinity for a developer containing water or improving the adhesion of the resist film to the substrate when the component (A1-1) is used for forming a resist film. It is effective in enhancing the sex.

As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, the lactone-containing monocyclic group is a group obtained by removing one hydrogen atom from a 4- to 6-membered ring lactone, such as a group obtained by removing one hydrogen atom from β-propionolactone, or γ-butyrolactone. Examples thereof include a group in which one hydrogen atom has been removed, and a group in which one hydrogen atom has been removed from δ-valerolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.

  More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基であり；Ｒ’はそれぞれ独立に水素原子、炭素数１〜５のアルキル基、炭素数１〜５のアルコキシ基または−ＣＯＯＲ”であり、Ｒ”は水素原子またはアルキル基であり；Ｒ^２９は単結合または２価の連結基であり、ｓ”は０または１〜２の整数であり；Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり；ｍは０または１の整数である。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; R ′ each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or —COOR; R "is a hydrogen atom or an alkyl group; R ²⁹ is a single bond or a divalent linking group; s" is 0 or an integer of 1 to 2; A "is an oxygen atom or a sulfur atom. An alkylene group having 1 to 5 carbon atoms, an oxygen atom or a sulfur atom, and m is an integer of 0 or 1. ]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a1).
Examples of the alkyl group having 1 to 5 carbon atoms of R ′ include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkoxy group having 1 to 5 carbon atoms of R ′ include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group.
R ′ is preferably a hydrogen atom in view of industrial availability.
R ″ is preferably a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 15 carbon atoms.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Or a monocycloalkane which may or may not be substituted with a fluorinated alkyl group; a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as a bicycloalkane, tricycloalkane or tetracycloalkane Specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Etc.
A ″ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.
R ²⁹ is a single bond or a divalent linking group. The divalent linking group is the same as the divalent linking group described for Y ² in the general formula (a1-0-2), and among them, an alkylene group and an ester bond (—C (═O ) -O-) or a combination thereof. The alkylene group as the divalent linking group for R ²⁹ is more preferably a linear or branched alkylene group. Specifically, the same as the linear alkylene group and the branched alkylene group mentioned as the aliphatic hydrocarbon group for A in Y ² can be used.
s ″ is preferably an integer of 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are illustrated below.
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

In the component (A1-1), as the structural unit (a2), one type of structural unit may be used alone, or two or more types may be used in combination.
As the structural unit (a2), at least one selected from the group consisting of structural units represented by the general formulas (a2-1) to (a2-5) is preferable, and the general formulas (a2-1) to ( At least one selected from the group consisting of structural units represented by a2-3) is more preferred. Among them, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-7), (a2-3-1) and (a2-3-5) It is preferable to use at least one selected from the group consisting of structural units represented by

  The proportion of the structural unit (a2) in the component (A1-1) is preferably 5 to 60 mol%, more preferably 10 to 50 mol%, based on the total of all the structural units constituting the component (A1-1). Preferably, 20-50 mol% is more preferable. By setting it to the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

(Structural unit (a3))
The structural unit (a3) is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.
When the component (A1-1) has the structural unit (a3), the hydrophilicity of the component (A1-1) is increased, the affinity with the developer is increased, and the alkali solubility in the exposed area is improved. Contributes to improved resolution.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom. A hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a cyclic aliphatic hydrocarbon group (cyclic group). The cyclic group may be a monocyclic group or a polycyclic group. For example, a resin for a resist composition for an ArF excimer laser can be appropriately selected from those proposed. The cyclic group is preferably a polycyclic group, and more preferably 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom Is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.

  The structural unit (a3) is derived from a hydroxyethyl ester of acrylic acid when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms. When the hydrocarbon group is a polycyclic group, the structural unit represented by the following formula (a3-1), the structural unit represented by the formula (a3-2), the formula ( The structural unit represented by a3-3) is preferred.

（式中、Ｒは前記と同じであり、ｊは１〜３の整数であり、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。）

(In the formula, R is the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t 'is an integer of 1 to 3, and l is an integer of 1 to 5) And s is an integer of 1 to 3.)

In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
j is preferably 1, and a hydroxyl group bonded to the 3rd position of the adamantyl group is particularly preferred.

  In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.

  In formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1. In these, a 2-norbornyl group or a 3-norbornyl group is preferably bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
In the component (A1-1), the proportion of the structural unit (a3) is preferably 5 to 50 mol% with respect to the total of all the structural units constituting the component (A1-1), and 10 to 40 mol. % Is more preferable. By setting it to the lower limit value or more, the effect of containing the structural unit (a3) is sufficiently obtained, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

(Other structural units)
The component (A1-1) may contain other structural units other than the structural units (a1) to (a3).
Such other structural unit is not particularly limited as long as it is a structural unit not classified into the above structural units (a1) to (a3), and is used for resist resins for ArF excimer laser, KrF excimer laser, and the like. Many things conventionally known as a thing can be used.
The other structural unit is preferably a structural unit derived from a compound copolymerizable with the compound that derives the structural units (a1) to (a3), and includes, for example, an acid non-dissociable aliphatic polycyclic group. And a structural unit derived from an acrylate ester (hereinafter this structural unit is referred to as “structural unit (a4)”).

Structural Unit (a4) The structural unit (a4) is a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic polycyclic group.
When the component (A1-1) has the structural unit (a4), lithography characteristics such as a depth of focus (DOF), resolution, and exposure margin (EL margin) are improved. In addition, the etching resistance is improved by the improvement of the carbon density.
Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and for ArF excimer laser and KrF excimer laser (preferably for ArF excimer laser). A number of hitherto known materials can be used as the resin component of the resist composition.
In particular, at least one selected from a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include those represented by the following general formulas (a4-1) to (a4-5).

（式中、Ｒは前記と同じである。）

(In the formula, R is as defined above.)

As the structural unit (a4), one type may be used alone, or two or more types may be used in combination.
When the component (A1-1) has the structural unit (a4), the proportion of the structural unit (a4) is 1 to 30 mol% with respect to the total of all the structural units constituting the component (A1-1). It is preferably 5 to 20 mol%. By setting it to the lower limit value or more, the effect of containing the structural unit (a4) is sufficiently obtained, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

In the first resist material, the component (A1-1) is preferably a polymer compound having the structural unit (a1).
Examples of the component (A1-1) include a copolymer composed of the structural units (a1), (a2) and (a3); and a structural unit (a1), (a2), (a3) and (a4). A copolymer etc. can be illustrated.

(A1-1) A component may be used individually by 1 type and may use 2 or more types together.
As the component (A1-1), a copolymer containing the following combination of structural units is particularly preferable.

［式中、Ｒは前記と同じである。複数のＲはそれぞれ同じであっても異なっていてもよい。Ｒ^１１は上記式（ａ１−１−０１）におけるＲ^１１と同じである。］

[Wherein, R is the same as defined above. A plurality of R may be the same or different. R ¹¹ is the same as ^{R 11} in the formula (a1-1-01). ]

In the above formula, R is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom or a methyl group.
R ¹¹ is preferably a methyl group or an ethyl group, and more preferably a methyl group.

The component (A1-1) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN). it can.
For the component (A1-1), a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination in the polymerization. it may be introduced -C _{(CF 3)} 2 -OH group at the terminal. As described above, a copolymer introduced with a hydroxyalkyl group in which a part of hydrogen atoms of the alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing

The mass average molecular weight (Mw) of the component (A1-1) before purification (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, preferably 1000 to 50000, more preferably 1500 to 30000, and more preferably 2000 to 20000. Is most preferred. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) of the component (A1-1) before purification is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. preferable. In addition, Mn shows that it is a number average molecular weight.

When a low molecular compound component whose solubility in an alkali developer is increased by the action of an acid in addition to the component (A1-1) as the base component in the first resist material, the low molecular compound component has a molecular weight It is preferable to use a low molecular compound having an acid dissociable, dissolution inhibiting group and a hydrophilic group as exemplified in the description of the component (A1-1). Specifically, a compound in which a part of hydrogen atoms of a hydroxyl group of a compound having a plurality of phenol skeletons is substituted with the acid dissociable, dissolution inhibiting group can be mentioned.
For example, the low molecular compound component is a sensitizer in a non-chemically amplified g-line or i-line resist, or a part of the hydrogen atom of the hydroxyl group of a low molecular weight phenol compound known as a heat resistance improver. Those substituted with a dissociable, dissolution inhibiting group are preferred and can be arbitrarily used.
Examples of such low molecular weight phenol compounds include bis (4-hydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, 2- (4-hydroxyphenyl) -2- (4′-hydroxyphenyl). ) Propane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ′, 3 ′, 4′-trihydroxyphenyl) propane, tris (4-hydroxyphenyl) methane, bis (4-hydroxy-) 3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3, 4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyph Phenylmethane, bis (4-hydroxy-3-methylphenyl) -3,4-dihydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl- 4-hydroxy-6-methylphenyl) -3,4-dihydroxyphenylmethane, 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, Examples include 2, 3, 4 nuclei of formalin condensates of phenols such as phenol, m-cresol, p-cresol or xylenol. Of course, it is not limited to these.
The acid dissociable, dissolution inhibiting group is not particularly limited, and examples thereof include those described above.
The low molecular compound component may be used alone or in combination of two or more.

[(A1-2) component]
When the first resist material is a “negative chemically amplified resist composition”, the component (A1) is a resin soluble in an alkali developer (hereinafter referred to as an alkali-soluble resin used for the first resist material). Is referred to as “(A1-2) component”).
In such a negative chemically amplified resist composition, in addition to using the component (A1-2) as a base material component, a crosslinking agent component (C) (hereinafter referred to as “component (C)”) is further used. It is preferable to use it.
In the negative chemically amplified resist composition, when an acid is generated from the component (B) upon exposure, the acid acts to cause crosslinking between the component (A1-2) and the component (C). Changes to poorly soluble in developer. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the negative chemically amplified resist composition on the substrate is selectively exposed, the exposed portion turns into poorly soluble in an alkaline developer. Since the unexposed area remains soluble in the alkali developer, the resist pattern can be formed by alkali development.

The component (A1-2) is, for example, α- (hydroxyalkyl) acrylic acid or an alkyl ester of α- (hydroxyalkyl) acrylic acid (preferably having 1 carbon atom) disclosed in JP-A-2000-206694. Resin having a unit derived from at least one selected from alkyl ester of ˜5; (meth) acrylic resin or polycycloolefin resin having sulfonamide group disclosed in US Pat. No. 6,949,325; US Pat. (Meth) acrylic resin containing a fluorinated alcohol disclosed in Japanese Patent No. 6949325, Japanese Patent Application Laid-Open No. 2005-336452, and Japanese Patent Application Laid-Open No. 2006-317803; Polycycloolefin resin having fluorinated alcohol However, a good resist pattern with less swelling can be formed, which is preferable.
The α- (hydroxyalkyl) acrylic acid is composed of acrylic acid in which a hydrogen atom is bonded to the α-position carbon atom to which the carboxy group is bonded, and a hydroxyalkyl group (preferably having a carbon number) in the α-position carbon atom. One or both of α-hydroxyalkylacrylic acid to which 1-5 hydroxyalkyl groups) are bonded.

  In the first resist material, the content of the component (A1) may be adjusted according to the resist film thickness to be formed.

<(S1) component>
As the component (S1), any component capable of dissolving the component (A1) and capable of preparing the first resist material as a uniform solution may be used, and conventionally known as a solvent for chemically amplified resists. Any one or two or more of them can be appropriately selected and used.
Preferred examples of the component (S1) include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; ethylene Polyhydric alcohols such as glycol, diethylene glycol, propylene glycol, dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, the polyhydric alcohols Or monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether, and monobutyl ether of the compound having an ester bond. Or derivatives of polyhydric alcohols such as compounds having an ether bond such as monophenyl ether [in these, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred]; methyl lactate, ethyl lactate (EL), esters such as methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene , Aromatic organic solvents such as mesitylene, tetrahydrofuran and the like.

(S1) A component may be used independently and may be used as 2 or more types of mixed solvents.
Of these, γ-butyrolactone, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and ethyl lactate (EL) are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is also preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, and is preferably in the range of 1: 9 to 9: 1. 2: 8 to 8: A range of 2 is more preferable.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S1), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.

  The amount of the component (S1) used is not particularly limited, is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. In general, the solid content concentration of the first resist material Is used in a range of 0.5 to 20% by mass, preferably 1 to 15% by mass.

<(B) component>
In the first resist material, the component (B) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used.
Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, poly (bissulfonyl) diazomethanes, and the like. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.
As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、アリール基またはアルキル基を表し；式（ｂ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか２つが相互に結合して式中のイオウ原子と共に環を形成してもよく；Ｒ^４”は、置換基を有していてもよいアルキル基、ハロゲン化アルキル基、アリール基、またはアルケニル基を表し；Ｒ^１”〜Ｒ^３”のうち少なくとも１つはアリール基を表し、Ｒ^５”〜Ｒ^６”のうち少なくとも１つはアリール基を表す。］

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group; among R ¹ ″ to R ³ ″ in formula (b-1), Any two may be bonded to each other to form a ring together with the sulfur atom in the formula; R ⁴ ″ may be an optionally substituted alkyl group, halogenated alkyl group, aryl group, or alkenyl group; And at least one of R ¹ ″ to R ³ ″ represents an aryl group, and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. In addition, any two of R ¹ ″ to R ³ ″ in formula (b-1) may be bonded to each other to form a ring together with the sulfur atom in the formula.
Further, at least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably R ¹ ″ to R ³ ″ are all aryl groups.

The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups It may be substituted with a group, a halogen atom, a hydroxyl group or the like, or may not be substituted.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Is most preferred.
As the alkoxy group that may be substituted for the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, A tert-butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
The halogen atom that may be substituted with the hydrogen atom of the aryl group is preferably a fluorine atom.

The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.

When any two of R ¹ ″ to R ³ ″ in the formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, a 3 to 10 membered ring including the sulfur atom is formed. It is preferable that a 5- to 7-membered ring is formed.
When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, the remaining one may be an aryl group preferable. Examples of the aryl group include the same aryl groups as those described above for R ¹ ″ to R ³ ″.

  Preferred examples of the cation moiety of the compound represented by the formula (b-1) include cations represented by the following formulas (I-1-1) to (I-1-8) having a triphenylmethane skeleton. Can be mentioned.

Moreover, as a cation part of an onium salt type | system | group acid generator, the cation represented by following formula (I-1-9)-(I-1-10) is also preferable.
In the following formulas (I-1-9) to (I-1-10), R ²⁷ and R ³⁹ are each independently a phenyl group, a naphthyl group, or a carbon number of 1 to 5 which may have a substituent. An alkyl group, an alkoxy group, and a hydroxyl group.
v is an integer of 1 to 3, and 1 or 2 is most preferable.

R ⁴ ″ represents an alkyl group, a halogenated alkyl group, an aryl group, or an alkenyl group which may have a substituent.
The alkyl group for R ⁴ ″ may be linear, branched or cyclic.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
Examples of the halogenated alkyl group for R ⁴ ″ include groups in which part or all of the hydrogen atoms of the linear, branched, or cyclic alkyl group have been substituted with halogen atoms. A fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
In the halogenated alkyl group, the ratio of the number of halogen atoms to the total number of halogen atoms and hydrogen atoms contained in the halogenated alkyl group (halogenation rate (%)) is preferably 10 to 100%. 50 to 100% is preferable, and 100% is most preferable. The higher the halogenation rate, the better the acid strength.
The aryl group for R ⁴ ″ is preferably an aryl group having 6 to 20 carbon atoms.
The alkenyl group in R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.
In the above R ⁴ ″, “optionally substituted” means one of hydrogen atoms in the linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl group. It means that part or all may be substituted with a substituent (an atom or group other than a hydrogen atom).
The number of substituents in R ⁴ ″ may be one, or two or more.

Examples of the substituent include a halogen atom, a hetero atom, an alkyl group, and a formula: XQ ^1- [wherein Q ¹ is a divalent linking group containing an oxygen atom, and X has a substituent. And a hydrocarbon group having 3 to 30 carbon atoms. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described as the halogen atom and alkyl group in the halogenated alkyl group in R ⁴ ″.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

X-Q 1 ^- In the group represented by, Q ¹ represents a divalent linking group containing an oxygen atom.
Q ¹ may contain an atom other than an oxygen atom. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, and nitrogen atoms.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond; —O—), an ester bond (—C (═O) —O—), and an amide bond (—C (═O) —NH. -), A carbonyl group (-C (= O)-), a non-hydrocarbon oxygen atom-containing linking group such as a carbonate bond (-O-C (= O) -O-); the non-hydrocarbon oxygen atom Examples include a combination of a containing linking group and an alkylene group.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —O—C (═O) — , R ^{91 to} R ⁹³ are each independently an alkylene group.) And the like.
The alkylene group for R ^{91 to} R ⁹³ is preferably a linear or branched alkylene group, and the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. preferable.
Specific examples of the alkylene group include a methylene group [—CH ₂ —]; —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ) ₂ —, —C ( _{CH 3) (CH 2 CH 3} ) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _[-CH 2 CH _2— ]; —CH (CH ₃ ) CH ₂ —, —CH (CH ₃ ) CH (CH ₃ ) —, —C (CH ₃ ) ₂ CH ₂ —, —CH (CH ₂ CH ₃ ) CH ₂ — and the like. Alkylethylene groups; trimethylene groups (n-propylene groups) [—CH ₂ CH ₂ CH ₂ —]; alkyls such as —CH (CH ₃ ) CH ₂ CH ₂ — and —CH ₂ CH (CH ₃ ) CH ₂ — trimethylene; tetramethylene group _[-CH 2 _CH 2 C _{2 CH 2 -]; - CH} (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - alkyl tetramethylene group and the like; pentamethylene group _[-CH 2 _CH 2 CH ₂ CH ₂ CH ₂ —] and the like.
Q ¹ is preferably a divalent linking group containing an ester bond or an ether bond, and in particular, —R ⁹¹ —O—, —R ⁹² —O—C (═O) — or —C (═O) — O—R ⁹³ —O—C (═O) — is preferred.

In the group represented by XQ ^1- , the hydrocarbon group of X may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.

The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms in the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups. Examples include heteroarylalkyl groups in which some of the carbon atoms constituting the ring are substituted with the above heteroatoms.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The aliphatic hydrocarbon group for X may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X, the aliphatic hydrocarbon group may have a part of the carbon atoms constituting the aliphatic hydrocarbon group substituted by a substituent containing a hetero atom, and the hydrogen atom constituting the aliphatic hydrocarbon group May be substituted with a substituent containing a hetero atom.
The “heteroatom” in X is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed of only the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of the carbon atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. —, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group, an acyl group, etc.), —S—, —S (═O) ₂ —, — S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms are removed from a monocycloalkane; a group in which one or more hydrogen atoms are removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and has one or more hydrogen atoms from the polycycloalkane. Excluded groups are preferred, and most preferred are groups in which one or more hydrogen atoms have been removed from adamantane.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include groups represented by the following formulas (L1) to (L5) and (S1) to (S4).

［式中、Ｑ”は炭素数１〜５のアルキレン基、−Ｏ−、−Ｓ−、−Ｏ−Ｒ^９４−または−Ｓ−Ｒ^９５−であり、Ｒ^９４およびＲ^９５はそれぞれ独立に炭素数１〜５のアルキレン基であり、ｍは０または１の整数である。］

[Wherein, Q ″ is an alkylene group having 1 to 5 carbon atoms, —O—, —S—, —O—R ⁹⁴ — or —S—R ⁹⁵ —, and R ⁹⁴ and R ⁹⁵ are each independently carbon. An alkylene group of 1 to 5 and m is an integer of 0 or 1.]

In the formula, examples of the alkylene group for Q ″, R ⁹⁴ and R ⁹⁵ include the same alkylene groups as those described above for R ^{91 to} R ⁹³ .
In these aliphatic cyclic groups, a part of hydrogen atoms bonded to carbon atoms constituting the ring structure may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
As said alkyl group, a C1-C5 alkyl group is preferable, and it is especially preferable that they are a methyl group, an ethyl group, a propyl group, n-butyl group, and a tert- butyl group.
Examples of the alkoxy group and the halogen atom are the same as those exemplified as the substituent for substituting part or all of the hydrogen atoms.

Among the above, X is preferably a cyclic group which may have a substituent. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. It is preferably an aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. Examples of the polycyclic aliphatic cyclic group include groups obtained by removing one or more hydrogen atoms from the polycycloalkane, groups represented by the above (L2) to (L5) and (S3) to (S4). Etc. are preferred.

Further, X is particularly preferably one having a polar site because the lithography properties and the resist pattern shape are further improved.
As what has a polar site | part, the carbon atom which comprises the aliphatic cyclic group of X mentioned above, for example, the substituent in which a hetero atom contains, ie, -O-, -C (= O) -O-. , —C (═O) —, —O—C (═O) —O—, —C (═O) —NH—, —NH— (H is substituted with a substituent such as an alkyl group or an acyl group) may _{be), - S -, - S} (= O) 2 -, - S (= O) 2 -O- , etc., in include those substituted.

R ⁴ "is, ^{X-Q 1} - as a substituent preferably has the case, ^{R 4."} The, ^{X-Q 1} -Y 1 - in the Formula, ^{Q 1} and X are the same as defined above , Y ¹ is an optionally substituted alkylene group having 1 to 4 carbon atoms or an optionally substituted fluorinated alkylene group having 1 to 4 carbon atoms. ] Is preferable.
In the group represented by XQ ¹ -Y ^1- , the alkylene group for Y ¹ includes the same alkylene groups as those described above for Q ¹ having 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group for Y ¹ include groups in which some or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.
As Y ^1, _{specifically, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF (CF 2 CF 3) -, _{-C (CF 3) 2 -,} - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF ₃ ) —, —C (CF ₃ ) ₂ CF ₂ —, —CF (CF ₂ CF ₃ ) CF ₂ —, —CF (CF ₂ CF ₂ CF ₃ ) —, —C (CF ₃ ) (CF _{2 CF 3) -; - CHF} -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 -, - CH (CF 2 _{CF 3) -, - C (} CH 3) (CF 3) -, - CH 2 CH 2 CH 2 CF 2 -, - C H ₂ CH ₂ CF ₂ CF ₂ —, —CH (CF ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CF ₃ ) CH ₂ —, —CH (CF ₃ ) CH (CF ₃ ) —, —C ( _{CF 3) 2 CH 2 -;} - CH 2 -, - CH 2 CH 2 -, - CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 -, - CH (CH 2 CH 3) -, - _{C (CH 3) 2 -,} - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH (CH 3) CH _{(CH 3) -, - C} (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH 2 CH 3) -, - C (CH 3) (CH 2 CH ₃ ) — and the like.

Y ¹ is preferably a fluorinated alkylene group, and particularly preferably a fluorinated alkylene group in which the carbon atom bonded to the adjacent sulfur atom is fluorinated. Examples of such fluorinated alkylene _{group, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF 2 CF 2 CF 2 CF 2 _{-, - CF (CF 3)} CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, _{-CF (CF 2 CF 3) CF} 2 -; - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -; - CH 2 CH 2 CH 2 CF 2 -, - CH ₂ CH ₂ CF ₂ CF ₂ —, —CH ₂ CF ₂ CF ₂ CF ₂ — and the like can be mentioned.
Of _{these, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is _{preferable, -CF 2 -, - CF 2} CF 2 - or -CF ₂ CF ₂ CF ₂ - is more preferable, -CF ₂ - is particularly preferred.

The alkylene group or fluorinated alkylene group may have a substituent. An alkylene group or a fluorinated alkylene group has a “substituent” means that part or all of the hydrogen atom or fluorine atom in the alkylene group or fluorinated alkylene group is substituted with an atom or group other than a hydrogen atom and a fluorine atom. Means that
Examples of the substituent that the alkylene group or fluorinated alkylene group may have include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxyl group.

In the formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. It is preferable that all of R ⁵ ″ to R ⁶ ″ are aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that R ⁵ ″ to R ⁶ ″ are all phenyl groups.
"The, ^{R 4} in the above formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

  Specific examples of the onium salt acid generators represented by formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. Trifluoromethane sulfonate or nonafluorobutane sulfonate, triphenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its Nonafluorobutanesulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of monophenyldimethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of diphenylmonomethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate , Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate, di (1-naphthyl) phenyl sulphonium trifluoromethane sulphonate, its heptafluoropropane sulphonate or its nonafluorobutane sulphonate; 1-phenyltetrahydrothiophenium trifluoromethane sulphonate, its heptafluoropropane sulphonate Or nonafluorobutanesulfonate thereof; 1- (4-methylphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonaflu 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1-phenyltetrahydrothiopyranium trifluoromethanesulfonate , Its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-hydroxyphenyl) tetrahydrothiopyranium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl -4-Hydroxyphenyl) tetrahydrothiopyranium trifluoromethanesulfonate, its heptafluoropropanes Honeto or nonafluorobutanesulfonate; 1- (4-methylphenyl) trifluoromethanesulfonate tetrahydrothiophenium Pila chloride, heptafluoropropane sulfonate or its nonafluorobutane sulfonate, and the like.

  In addition, the anion portion of these onium salts may be substituted with methanesulfonate, n-propanesulfonate, n-butanesulfonate, n-octanesulfonate, 1-adamantansulfonate, 2-norbornanesulfonate, or the like; d-camphor-10-sulfonate Further, onium salts substituted with sulfonates such as benzenesulfonate, perfluorobenzenesulfonate, and p-toluenesulfonate can also be used.

  Moreover, the onium salt which replaced the anion part of these onium salts by the anion represented by either of following formula (b1)-(b8) can also be used.

［式中、ｙは１〜３の整数であり、ｑ１〜ｑ２はそれぞれ独立に１〜５の整数であり、ｑ３は１〜１２の整数であり、ｔ３は１〜３の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｊは１〜２０の整数であり、Ｒ^５０は置換基であり、ｍ１〜ｍ５はそれぞれ独立に０または１であり、ｖ０〜ｖ５はそれぞれ独立に０〜３の整数であり、ｗ１〜ｗ５はそれぞれ独立に０〜３の整数であり、Ｑ”は前記と同じである。］

[Wherein y is an integer of 1 to 3, q1 and q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, t3 is an integer of 1 to 3, and r1 ~r2 are each independently an integer of 0 to 3, j is an integer from 1 to ^{20, R 50} is a substituent, m1 to m5 are each independently 0 or 1, v0~v5 each Each independently represents an integer of 0 to 3, w1 to w5 are each independently an integer of 0 to 3, and Q ″ is the same as defined above.]

Examples of the substituent for R ⁵⁰ are the same as those described above as the substituent that the aliphatic hydrocarbon group may have and the substituent that the aromatic hydrocarbon group may have in X. Can be mentioned.
Code (r1 and r2, w1 to w5) attached to R ⁵⁰ when it is 2 or more integer, a plurality of ^{R 50} in the compound may be the same, respectively, it may be different.

As the onium salt-based acid generator, in the general formula (b-1) or (b-2), the anion moiety ^(R 4 "SO ₃ ^-) of the following general formula (b-3) or (b- An onium salt acid generator substituted with the anion represented by 4) can also be used (the cation moiety is the same as the cation moiety in the formula (b-1) or (b-2)).

［式中、Ｘ”は、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙ”、Ｚ”は、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。］

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms and substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Most preferably, it has 3 carbon atoms.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably Has 1 to 7 carbon atoms, more preferably 1 to 3 carbon atoms.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, as the number of hydrogen atoms substituted with fluorine atoms increases, the strength of the acid increases, and high-energy light or electron beam of 200 nm or less This is preferable because the transparency to the surface is improved.
The proportion of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all hydrogen atoms are substituted with fluorine atoms. A perfluoroalkylene group or a perfluoroalkyl group.

As the onium salt-based acid generator, in the general formula (b-1) or (b-2), anion ^{- a, R a -COO (R 4 "} SO 3) - [ wherein, ^{R a} Is an alkyl group or a fluorinated alkyl group.] An onium salt-based acid generator substituted with a cation moiety can also be used (the cation moiety is the same as the cation moiety in the formula (b-1) or (b-2)).
In the above formula, as R ^{a, the same} as R ⁴ ″ can be mentioned.
Specific examples of the “R ^a —COO ⁻ ” include trifluoroacetate ions, acetate ions, 1-adamantanecarboxylate ions and the like.

  Moreover, the sulfonium salt which has a cation part represented by the following general formula (b-5) or (b-6) can also be used as an onium salt type | system | group acid generator.

［式中、Ｒ^８１〜Ｒ^８６はそれぞれ独立してアルキル基、アセチル基、アルコキシ基、カルボキシ基、水酸基またはヒドロキシアルキル基であり；ｎ_１〜ｎ_５はそれぞれ独立して０〜３の整数であり、ｎ_６は０〜２の整数である。］

[Wherein R ^{81 to} R ⁸⁶ are each independently an alkyl group, acetyl group, alkoxy group, carboxy group, hydroxyl group or hydroxyalkyl group; n _{1 to} n ₅ are each independently an integer of 0 to 3; There, _{n 6} is an integer of 0-2. ]

In R ^{81 to} R ⁸⁶ , the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group, and a methyl group, an ethyl group, a propyl group, an isopropyl group, n A butyl group or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{1 to} n ₆ attached to R ^{81 to} R ⁸⁶ are integers of 2 or more, the plurality of R ^{81 to} R ⁸⁶ may be the same or different.
n ₁ is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
n ₂ and n ₃ are preferably each independently 0 or 1, more preferably 0.
n ₄ is preferably 0 to 2, more preferably 0 or 1.
n ₅ is preferably 0 or 1, more preferably 0.
n ₆ is preferably 0 or 1, more preferably 1.

The anion part of the sulfonium salt having a cation part represented by the formula (b-5) or (b-6) is not particularly limited, and is the same as the anion part of the onium salt acid generators proposed so far. It may be a thing. Examples of the anion moiety include fluorinated alkyl sulfonate ions such as the anion moiety (R ⁴ ″ SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2). An anion represented by the above general formula (b-3) or (b-4).

  In this specification, the oxime sulfonate acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation (exposure) of radiation. It is what you have. Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

(In formula (B-1), R ³¹ and R ³² each independently represents an organic group.)

The organic groups of R ³¹ and R ³² are groups containing carbon atoms, and atoms other than carbon atoms (for example, hydrogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms (fluorine atoms, chlorine atoms, etc.), etc.) You may have.
As the organic group for R ^31, a linear, branched, or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned. Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable. The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ³¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms having no substituent or a fluorinated alkyl group having 1 to 4 carbon atoms.
As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

  More preferable examples of the oxime sulfonate-based acid generator include compounds represented by the following general formula (B-2) or (B-3).

［式（Ｂ−２）中、Ｒ^３３は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３４はアリール基である。Ｒ^３５は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³³ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁴ is an aryl group. R ³⁵ represents an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３６はシアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３７は２または３価の芳香族炭化水素基である。Ｒ^３８は置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐ”は２または３である。］

[In Formula (B-3), R ³⁶ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁷ is a divalent or trivalent aromatic hydrocarbon group. ^R38 is an alkyl group having no substituent or a halogenated alkyl group. p ″ is 2 or 3.]

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and carbon atoms. Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred.
As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.
The alkyl group or halogenated alkyl group having no substituent of R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁶ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^33. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁷ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³⁴ .
Examples of the alkyl group or halogenated alkyl group having no substituent of R ³⁸ include the same alkyl groups or halogenated alkyl groups as those having no substituent of R ³⁵ .
p ″ is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope Nthenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), pamphlet of International Publication No. 04/074242, An oxime sulfonate-based acid generator disclosed in Examples 1 to 40) on pages 65 to 85 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Further, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can also be suitably used.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane and 1,4-bis (phenylsulfonyldiazo) disclosed in JP-A-11-322707. Methylsulfonyl) butane, 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3 -Bis (cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane, etc. Door can be.

As the component (B), one type of acid generator described above may be used alone, or two or more types may be used in combination.
Among these, as the component (B), the anion moiety (R ⁴ ″ SO ₃ ⁻ ) in the formula (b-1) and the onium salt acid having an anion represented by the formula (b-3) in the anion moiety are used. It is preferable to use a generator.
In the first resist material, the content of the component (B) is preferably 0.5 to 50 parts by mass and more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the component (A1). By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<Optional component>
[Component (C)]
When the first resist material is a “negative type chemically amplified resist composition”, the first resist material contains the component (A1-2) as a base material component, and further contains a crosslinking agent component (( C) component) is preferably contained.
The component (C) is not particularly limited, and can be arbitrarily selected from cross-linking agents used in chemically amplified negative resist compositions known so far.
Specifically, for example, 2,3-dihydroxy-5-hydroxymethylnorbornane, 2-hydroxy-5,6-bis (hydroxymethyl) norbornane, cyclohexanedimethanol, 3,4,8 (or 9) -trihydroxytri Aliphatic cyclic carbonization having a hydroxyl group or a hydroxyalkyl group or both such as cyclodecane, 2-methyl-2-adamantanol, 1,4-dioxane-2,3-diol, 1,3,5-trihydroxycyclohexane Examples thereof include hydrogen and oxygen-containing derivatives thereof.

In addition, amino group-containing compounds such as melamine, acetoguanamine, benzoguanamine, urea, ethylene urea, propylene urea, glycoluril are reacted with formaldehyde or formaldehyde and lower alcohol, and the hydrogen atom of the amino group is hydroxymethyl group or lower alkoxymethyl. And a compound substituted with a group and a compound having an epoxy group.
Of these, those using melamine are melamine-based crosslinking agents, those using urea are urea-based crosslinking agents, those using alkylene ureas such as ethylene urea and propylene urea are alkylene urea-based crosslinking agents, and glycoluril is used. What was used was a glycoluril-based crosslinking agent, and what used an epoxy group-containing compound was called an epoxy-based crosslinking agent.
The component (C) is preferably at least one selected from the group consisting of melamine crosslinking agents, urea crosslinking agents, alkylene urea crosslinking agents, glycoluril crosslinking agents, and epoxy crosslinking agents. A glycoluril-based crosslinking agent is preferred.

  Melamine-based crosslinking agents include compounds in which melamine and formaldehyde are reacted to replace the amino group hydrogen atom with a hydroxymethyl group, and melamine, formaldehyde and lower alcohol are reacted to convert the amino group hydrogen atom into a lower alkoxy group. Examples include compounds substituted with a methyl group. Specific examples include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxybutyl melamine, and the like, among which hexamethoxymethyl melamine is preferable.

  Urea-based crosslinking agents include compounds in which urea and formaldehyde are reacted to replace amino group hydrogen atoms with hydroxymethyl groups, and urea, formaldehyde and lower alcohols are reacted to convert amino group hydrogen atoms into lower alkoxy groups. Examples include compounds substituted with a methyl group. Specific examples include bismethoxymethylurea, bisethoxymethylurea, bispropoxymethylurea, bisbutoxymethylurea, etc. Among them, bismethoxymethylurea is preferable.

  As an alkylene urea type crosslinking agent, the compound represented by the following general formula (C-1) is mentioned.

［式（Ｃ−１）中、Ｒ^５’とＲ^６’はそれぞれ独立に水酸基又は低級アルコキシ基であり、Ｒ^３’とＲ^４’はそれぞれ独立に水素原子、水酸基又は低級アルコキシ基であり、ｗは０又は１〜２の整数である。］

[In the formula (C-1), R ⁵ ′ and R ⁶ ′ are each independently a hydroxyl group or a lower alkoxy group, and R ³ ′ and R ⁴ ′ are each independently a hydrogen atom, a hydroxyl group or a lower alkoxy group, w is 0 or an integer of 1-2. ]

When R ⁵ ′ and R ⁶ ′ are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. R ⁵ ′ and R ⁶ ′ may be the same or different from each other. More preferably, they are the same.
When R ³ ′ and R ⁴ ′ are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. R ³ ′ and R ⁴ ′ may be the same or different from each other. More preferably, they are the same.
w is 0 or an integer of 1 to 2, preferably 0 or 1.
As the alkylene urea crosslinking agent, a compound in which w is 0 (ethylene urea crosslinking agent) and / or a compound in which w is 1 (propylene urea crosslinking agent) are particularly preferable.

  The compound represented by the general formula (C-1) can be obtained by a condensation reaction of alkylene urea and formalin, and by reacting this product with a lower alcohol.

  Specific examples of the alkylene urea crosslinking agent include, for example, mono and / or dihydroxymethylated ethylene urea, mono and / or dimethoxymethylated ethylene urea, mono and / or diethoxymethylated ethylene urea, mono and / or dipropoxy Ethylene urea-based crosslinking agents such as methylated ethylene urea, mono and / or dibutoxymethylated ethylene urea; mono and / or dihydroxymethylated propylene urea, mono and / or dimethoxymethylated propylene urea, mono and / or diethoxymethyl Propylene urea-based crosslinkers such as propylene urea, mono and / or dipropoxymethylated propylene urea, mono and / or dibutoxymethylated propylene urea; 1,3-di (methoxymethyl) 4,5-dihydroxy-2- Imidazolidinone, 1,3-di (Metoki Like, etc.) -4,5-dimethoxy-2-imidazolidinone.

Examples of the glycoluril-based crosslinking agent include glycoluril derivatives in which the N position is substituted with one or both of a hydroxyalkyl group and an alkoxyalkyl group having 1 to 4 carbon atoms. Such a glycoluril derivative can be obtained by a condensation reaction of glycoluril and formalin and by reacting this product with a lower alcohol.
Specific examples of the glycoluril-based crosslinking agent include, for example, mono, di, tri and / or tetrahydroxymethylated glycoluril; mono, di, tri and / or tetramethoxymethylated glycoluril; mono, di, tri and / or Tetraethoxymethylated glycoluril; mono, di, tri and / or tetrapropoxymethylated glycoluril; mono, di, tri and / or tetrabutoxymethylated glycoluril.

The epoxy-based crosslinking agent is not particularly limited as long as it has an epoxy group, and can be arbitrarily selected and used. Among them, those having two or more epoxy groups are preferable. By having two or more epoxy groups, crosslinking reactivity is improved.
The number of epoxy groups is preferably 2 or more, more preferably 2 to 4, and most preferably 2.
The following are suitable as the epoxy-based crosslinking agent.

As the component (C), one type may be used alone, or two or more types may be used in combination.
In the first resist material, the content of the component (C) is preferably 1 to 50 parts by weight, more preferably 3 to 30 parts by weight, and more preferably 3 to 15 parts by weight with respect to 100 parts by weight of the component (A1). Part is more preferable, and 5 to 10 parts by mass is most preferable. When the content of the component (C) is at least the lower limit value, crosslinking formation proceeds sufficiently and a good resist pattern with little swelling is obtained. Moreover, when it is less than or equal to this upper limit value, the storage stability of the resist coating solution is good and the deterioration of sensitivity over time is suppressed.

[(D) component]
The first resist material preferably further contains a nitrogen-containing organic compound component (D) (hereinafter referred to as “component (D)”) as an optional component.
The component (D) is not particularly limited as long as it acts as an acid diffusion control agent, that is, a quencher that traps the acid generated from the component (B) by exposure, and a wide variety of components have already been proposed. Therefore, any known one may be used. Of these, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are preferred.
An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkyl amine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms.
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine , Trialkylamines such as tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, Li isopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a trialkylamine having 5 to 10 carbon atoms is more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.

(D) A component may be used independently and may be used in combination of 2 or more type.
In the first resist material, the component (D) is usually used in the range of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the component (A1). By setting the content in the above range, the resist pattern shape, the stability over time, and the like are improved.

[(E) component]
The first resist material is a group consisting of organic carboxylic acid, phosphorus oxo acid and derivatives thereof as optional components for the purpose of preventing sensitivity deterioration and improving the resist pattern shape and stability with time. At least one compound (E) selected from (hereinafter referred to as “component (E)”) can be contained.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of phosphorus oxo acids include phosphoric acid, phosphonic acid, and phosphinic acid. Among these, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include esters in which the hydrogen atom of the oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. 15 aryl groups and the like.
Examples of phosphoric acid derivatives include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of phosphonic acid derivatives include phosphonic acid esters such as phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of the phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
(E) A component may be used individually by 1 type and may use 2 or more types together.
As the component (E), an organic carboxylic acid is preferable, and salicylic acid is particularly preferable.
In the first resist material, the component (E) is used in a proportion of 0.01 to 5.0 parts by mass per 100 parts by mass of the component (A1).

  The first resist material further includes miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coating properties, dissolution inhibitors, plasticizers, Stabilizers, colorants, antihalation agents, dyes, and the like can be added as appropriate.

  Dissolution of the component to be blended in the first resist material into the component (S1) can be carried out, for example, by simply mixing and stirring the above components by a usual method, and, if necessary, a dissolver or homogenizer You may disperse and mix using dispersers, such as a 3 roll mill. Moreover, after mixing, you may further filter using a mesh, a membrane filter, etc.

(Second resist material)
The second resist material contains a resin (A2) and an organic solvent (S2) (hereinafter also referred to as “component (S2)”) that dissolves the resin (A2) and does not dissolve the resin (A1). However, the solubility in an alkaline developer is changed by exposure.
The second resist material is preferably a chemically amplified resist composition containing an acid generator that generates an acid upon exposure. Specifically, the resin (A2) (hereinafter referred to as “component (A2)”). And the organic solvent (S2) which dissolves the resin (A2) and does not dissolve the resin (A1), and a resin whose solubility in an alkaline developer is changed by the action of an acid generated from the acid generator. What contains ((S2) component) and the said acid generator is mentioned as a suitable thing.
In addition to the (A2) component, the (S2) component and the acid generator, the second resist material includes, as optional components, a crosslinking agent component ((C) component), a nitrogen-containing organic compound component ((D) component); An organic carboxylic acid and at least one compound selected from the group consisting of phosphorus oxo acids and derivatives thereof (component (E)) may be contained.
Examples of the acid generator, (C) component, (D) component, and (E) component that may be contained in the second resist material include the (B) component, (C) component, and (D) in the first resist material. The thing similar to what was illustrated by description about a component and (E) component is mentioned.
The second resist material may be a negative resist composition or a positive resist composition. Whether the second resist material is a negative type or a positive type may be appropriately determined in view of a desired pattern shape, a combination with the first resist material, and the like.

<(A2) component>
The component (A2) is soluble in both the organic solvent (S2) and the organic solvent (W), and a polymer compound (resin) that has been used as a base material component for a chemically amplified resist so far. One kind can be used alone, or two or more kinds can be mixed and used.

When the second resist material in the present invention is a “positive chemically amplified resist composition”, the component (A2) is a resin (hereinafter referred to as “(A2-)” whose solubility in an alkaline developer is increased by the action of acid. 1) Component ")) is used.
The component (A2-1) is hardly soluble in an alkali developer before exposure, and when an acid is generated from the acid generator upon exposure, the solubility in the alkali developer is increased by the action of the acid. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the positive chemically amplified resist composition on the support is selectively exposed, the exposed portion is hardly soluble in an alkali developer. However, since the unexposed area remains hardly soluble in alkali and does not change, a resist pattern can be formed by alkali development.

  When the second resist material is a “positive chemically amplified resist composition”, the low molecular compound component described above may be used as the base material component in addition to the component (A2-1).

[(A2-1) component]
As the component (A2-1), a resin component (base resin) usually used as a base component for a chemically amplified resist can be used alone or in combination of two or more. .
Among the components (A2-1), preferred are those having a structural unit derived from an acrylate ester and those having a structural unit derived from hydroxystyrene, which are derived from an acrylate ester. What has a structural unit is more preferable.
Examples of the structural unit derived from the acrylate ester include the structural units (a1) to (a4) and the structural unit (a5) described later.
Examples of the structural unit derived from hydroxystyrene include the structural unit (a6) described later.
Moreover, you may have the structural unit (for example, below-mentioned structural unit (a7)) induced | guided | derived from styrene.

Here, in the present specification and claims, the “structural unit derived from hydroxystyrene” means a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene.
“Hydroxystyrene” is a concept including hydroxystyrene, and those in which the α-position hydrogen atom of hydroxystyrene is substituted with another substituent such as an alkyl group, and derivatives thereof. Note that the α-position (α-position carbon atom) of a structural unit derived from hydroxystyrene means a carbon atom to which a benzene ring is bonded, unless otherwise specified.
Specific examples of the alkyl group as a substituent at the α-position in hydroxystyrene include an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, and an isobutyl group. And a linear or branched alkyl group such as tert-butyl group, pentyl group, isopentyl group and neopentyl group.
“Structural unit derived from styrene” means a structural unit formed by cleavage of an ethylenic double bond of styrene.
In this specification, “styrene” refers to styrene and those in which the hydrogen atom at the α-position of styrene is substituted with another substituent such as an alkyl group, and derivatives thereof (excluding the above-mentioned hydroxystyrene). Include concepts. Moreover, what substituted the hydrogen atom of the phenyl group with substituents, such as a C1-C5 alkyl group, etc. shall also be included.

(Structural units (a1) to (a4))
The structural units (a1) to (a4) are the same as the structural units (a1) to (a4) in the component (A1-1) described above. Moreover, the preferable thing of each structural unit, and the content rate of each structural unit in (A2-1) component are also the same as that of the case in (A1-1) component, respectively.

(Structural unit (a5))
The structural unit (a5) is a structural unit represented by the following general formula (a5-1).

［式（ａ５−１）中、Ｒは水素原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基であり；Ｙ^５は置換基を有していてもよい脂肪族炭化水素基であり、Ｚは１価の有機基であり；ａは１〜３の整数であり、ｂは０〜２の整数であり、かつ、ａ＋ｂ＝１〜３であり；ｃ、ｄ、ｅはそれぞれ独立して０〜３の整数である。］

[In formula (a5-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; Y ⁵ may have a substituent. A hydrocarbon group, Z is a monovalent organic group; a is an integer of 1 to 3, b is an integer of 0 to 2, and a + b = 1 to 3; c, d , E are each independently an integer of 0-3. ]

  In formula (a5-1), the same as R in the structural unit (a1). Of these, R is preferably a hydrogen atom or a methyl group.

In formula (a5-1), Y ⁵ is an optionally substituted aliphatic hydrocarbon group.
The aliphatic hydrocarbon group for Y ⁵ may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
Here, in the present specification and claims, the “aliphatic hydrocarbon group” indicates an aliphatic hydrocarbon group having no aromaticity.
Further, “may have a substituent” means that a part of carbon atoms constituting the aliphatic hydrocarbon group may be substituted with a substituent containing a hetero atom, and the aliphatic hydrocarbon It means that part or all of the hydrogen atoms constituting the group may be substituted with a substituent containing a hetero atom.
The “heteroatom” in Y ⁵ is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may consist of only the hetero atom, or may be a group containing the hetero atom and a group or atom other than the hetero atom. Specifically, for example, —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O—, —C (═O) —NH—, -NH- (H is an alkyl group, may be substituted with a substituent such as an acyl _{group), - S -, - S} (= O) 2 -, - S (= O) 2 -O- and the like can be mentioned It is done. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms constituting the aliphatic hydrocarbon group include, for example, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (= O), cyano Group, alkyl group and the like.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.
As said alkyl group, a C1-C5 alkyl group (lower alkyl group), for example, a methyl group, an ethyl group, a propyl group, n-butyl group, a tert-butyl group etc. are mentioned.

Y ⁵ is linear, if a branched aliphatic hydrocarbon group, the carbon number 1 to 10 are preferred, more preferably 1 to 5, 1 to 3 being most preferred. Specifically, a chain alkylene group is preferable.

When Y ⁵ is a cyclic aliphatic hydrocarbon group (aliphatic cyclic group), the structure of the basic ring (aliphatic ring) excluding the substituent of the aliphatic cyclic group is a ring composed of carbon and hydrogen. It is not limited to being a (hydrocarbon ring), and a hetero atom such as an oxygen atom may be included in the structure of the ring (aliphatic ring). The “hydrocarbon ring” may be either saturated or unsaturated, but is usually preferably saturated.
The aliphatic cyclic group may be either a polycyclic group or a monocyclic group. Examples of the aliphatic cyclic group include a monocycloalkane which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group; a bicycloalkane, a tricycloalkane, or a tetracycloalkane. Groups obtained by removing two or more hydrogen atoms from polycycloalkanes and the like. More specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing two or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. .
Examples of the aliphatic cyclic group include two or more hydrogen atoms from tetrahydrofuran or tetrahydropyran which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group. Examples include groups other than.
The aliphatic cyclic group in the structural unit (a5) is preferably a polycyclic group, and particularly preferably a group obtained by removing two or more hydrogen atoms from adamantane.

In the general formula (a5-1), Z is a monovalent organic group.
Here, in the present specification and claims, the “organic group” means a group containing a carbon atom, and an atom other than a carbon atom (for example, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom) (A fluorine atom, a chlorine atom, etc.)).
Examples of the organic group represented by Z include an aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a formula -Q ⁵ -R ^5. Group (wherein Q ⁵ is a divalent linking group, and R ⁵ is an aliphatic hydrocarbon group which may have a substituent or an aromatic hydrocarbon group which may have a substituent). Is mentioned.

  In the organic group of Z, the aliphatic hydrocarbon group is, for example, a linear, branched or cyclic saturated hydrocarbon group having 1 to 20 carbon atoms, or a linear or branched chain having 2 to 20 carbon atoms. And an aliphatic unsaturated hydrocarbon group.

Examples of the linear saturated hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group.
Examples of the branched saturated hydrocarbon group include 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group. 2-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

The linear or branched alkyl group may have a substituent. Examples of the substituent include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), a cyano group, and a carboxy group.
As the alkoxy group as a substituent of the linear or branched alkyl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n- A butoxy group and a tert-butoxy group are preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent of the linear or branched alkyl group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
The halogenated alkyl group as a substituent for the aromatic group is a hydrogen atom of an alkyl group having 1 to 5 carbon atoms (preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc.). Examples thereof include a group in which part or all of the atoms are substituted with the halogen atom.

The cyclic saturated hydrocarbon group may be either a polycyclic group or a monocyclic group, and examples thereof include a cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, such as monocycloalkane; bicycloalkane, tricyclo And groups obtained by removing one hydrogen atom from polycycloalkane such as alkane and tetracycloalkane. More specifically, one hydrogen atom was removed from a monocycloalkane such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Group and the like.
The cyclic alkyl group may have a substituent. For example, part of the carbon atoms constituting the ring of the cyclic alkyl group may be substituted with a heteroatom, or the hydrogen atom bonded to the ring of the cyclic alkyl group may be substituted with a substituent. Good.
Examples of the former include one or more hydrogen atoms from a heterocycloalkane in which a part of the carbon atoms constituting the ring of the monocycloalkane or polycycloalkane is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Examples include groups other than atoms. The ring structure may have an ester bond (—C (═O) —O—). Specifically, a lactone-containing monocyclic group such as a group obtained by removing one hydrogen atom from γ-butyrolactone, or a group obtained by removing one hydrogen atom from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring. And other lactone-containing polycyclic groups.
Examples of the substituent in the latter example include the same as those exemplified as the substituent that the linear or branched alkyl group may have, an alkyl group having 1 to 5 carbon atoms, and the like.

Examples of the linear unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group.
Examples of the branched unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
The linear or branched unsaturated hydrocarbon group may have a substituent. Examples of the substituent include the same ones as those exemplified as the substituent which the linear or branched alkyl group may have.

In the organic group of Z, the aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
The aromatic organic group may have an aromatic hydrocarbon ring in which the ring skeleton of the aromatic ring is composed only of carbon atoms, and the aromatic ring group includes aromatic atoms containing hetero atoms other than carbon atoms. It may have a heterocyclic ring.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. A heteroaryl group in which a part of carbon atoms constituting the ring of these aryl groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom; a benzyl group, a phenethyl group, 1 -Arylalkyl groups such as naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, and the like. The number of carbon atoms in the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include a heteroaryl group in which a part of carbon atoms constituting the ring of the aryl group is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, or a carbon constituting the ring of the arylalkyl group. Examples include heteroarylalkyl groups in which a part of the atoms is substituted with the heteroatom.
Examples of the substituent of the aromatic group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and an acetyl group.
Examples of the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent of the aromatic group include those mentioned as the substituent that the linear or branched alkyl group may have. The same thing and a C1-C5 alkyl group are mentioned.

In the group represented by the formula -Q ⁵ -R ⁵ , Q ⁵ is a divalent linking group, and R ⁵ has an aliphatic hydrocarbon group or a substituent which may have a substituent. An aromatic hydrocarbon group that may be present.
Examples of the divalent linking group for Q ⁵ include the same groups as those exemplified in the description of Y ² in the above formula (a1-0-2).
R ⁵ may be the same as those exemplified in the description of the aliphatic hydrocarbon group and aromatic hydrocarbon group in Z above.

Among the above, the organic group of Z is a group containing an aliphatic hydrocarbon group which may have a substituent since the solubility in an organic solvent is further improved when a resist composition is formed. Preferably, the group represented by the formula -Q ⁵ -R ⁸ ′ (wherein Q ⁵ is a divalent linking group, and R ⁸ ′ is an aliphatic carbon which may have a substituent. It is more preferably a hydrogen group. Specifically, a tertiary alkyl group-containing group or an alkoxyalkyl group is preferable.

(Tertiary alkyl group-containing group)
Here, in the present specification and claims, the “tertiary alkyl group” refers to an alkyl group having a tertiary carbon atom. As described above, the “alkyl group” represents a monovalent saturated hydrocarbon group, and includes a chain (straight chain or branched chain) alkyl group and an alkyl group having a cyclic structure.
The “tertiary alkyl group-containing group” refers to a group containing a tertiary alkyl group in its structure. The tertiary alkyl group-containing group may be composed only of a tertiary alkyl group, or may be composed of a tertiary alkyl group and another atom or group other than the tertiary alkyl group. .
Examples of the “atom or group other than the tertiary alkyl group” that constitutes the tertiary alkyl group-containing group together with the tertiary alkyl group include a carbonyloxy group, a carbonyl group, an alkylene group, an oxygen atom, and the like. .

Examples of the tertiary alkyl group-containing group for Z include a tertiary alkyl group-containing group having no cyclic structure, a tertiary alkyl group-containing group having a cyclic structure, and the like.
A tertiary alkyl group-containing group having no cyclic structure is a group containing a branched tertiary alkyl group as the tertiary alkyl group and having no cyclic structure in the structure.
Examples of the branched tertiary alkyl group include groups represented by the following general formula (I).

In formula (I), R ^{21 to} R ²³ are each independently a linear or branched alkyl group. 1-5 are preferable and, as for carbon number of this alkyl group, 1-3 are more preferable.
Moreover, it is preferable that the total carbon number of group represented by general formula (I) is 4-7, it is more preferable that it is 4-6, and it is most preferable that it is 4-5.
Preferred examples of the group represented by the general formula (I) include a tert-butyl group and a tert-pentyl group, and a tert-butyl group is more preferable.

Examples of the tertiary alkyl group-containing group that does not have a cyclic structure include the above-described branched tertiary alkyl group; the above-described branched tertiary alkyl group is a linear or branched alkylene group A tertiary alkyl group-containing chain alkyl group bonded to the above; a tertiary alkyloxycarbonyl group having the branched tertiary alkyl group described above as the tertiary alkyl group; And tertiary alkyloxycarbonylalkyl groups having a branched tertiary alkyl group.
The alkylene group in the tertiary alkyl group-containing chain alkyl group is preferably an alkylene group having 1 to 5 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms, and further preferably an alkylene group having 2 to 2 carbon atoms.
Examples of the chain-like tertiary alkyloxycarbonyl group include a group represented by the following general formula (II). ^R 21 ^{to R 23} in the formula (II) is the same as ^R 21 ^{to R 23} in general formula (I). The chain-like tertiary alkyloxycarbonyl group is preferably a tert-butyloxycarbonyl group (t-boc) or a tert-pentyloxycarbonyl group.

Examples of the chain-like tertiary alkyloxycarbonylalkyl group include a group represented by the following general formula (III). ^R 21 ^{to R 23} in the formula (III) are the same as ^R 21 ^{to R 23} in general formula (I). f is an integer of 1 to 3, and 1 or 2 is preferable. As the chain-like tertiary alkyloxycarbonylalkyl group, a tert-butyloxycarbonylmethyl group and a tert-butyloxycarbonylethyl group are preferable.
Of these, the tertiary alkyl group-containing group having no cyclic structure is preferably a tertiary alkyloxycarbonyl group or a tertiary alkyloxycarbonylalkyl group, more preferably a tertiary alkyloxycarbonyl group. A tert-butyloxycarbonyl group (t-boc) is most preferred.

The tertiary alkyl group-containing group having a cyclic structure is a group having a tertiary carbon atom and a cyclic structure in the structure.
In the tertiary alkyl group-containing group having a cyclic structure, the cyclic structure preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and more preferably 6 to 10 carbon atoms constituting the ring. Most preferred. Examples of the cyclic structure include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. Preferable examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

Examples of the tertiary alkyl group-containing group having a cyclic structure include a group having the following group (1) or (2) as a tertiary alkyl group.
(1) A group in which a linear or branched alkyl group is bonded to a carbon atom constituting a ring of a cyclic alkyl group (cycloalkyl group), and the carbon atom is a tertiary carbon atom.
(2) A group in which an alkylene group having a tertiary carbon atom (branched alkylene group) is bonded to the carbon atom constituting the ring of the cycloalkyl group.

The linear or branched alkyl group in the group (1) preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. .
Examples of the group (1) include a 2-methyl-2-adamantyl group, a 2-ethyl-2-adamantyl group, a 1-methyl-1-cycloalkyl group, and a 1-ethyl-1-cycloalkyl group.

In the above (2), the cycloalkyl group to which the branched alkylene group is bonded may have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.
Examples of the group (2) include groups represented by the following chemical formula (IV).

In the formula (IV), R ²⁴ is a cycloalkyl group which may or may not have a substituent. Examples of the substituent that the cycloalkyl group may have include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (═O).
R ²⁵ and R ²⁶ are each independently a linear or branched alkyl group, and the alkyl group is the same as the alkyl group of R ^{21 to} R ²³ in the formula (I). Can be mentioned.

(Alkoxyalkyl group)
Examples of the alkoxyalkyl group for Z include groups represented by the following general formula (V).

In the formula, R ⁴¹ is a linear, branched or cyclic alkyl group.
When R ⁴¹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ⁴¹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. For example, one or more hydrogen atoms from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group And the like except for. More specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. . Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
^R42 is a linear or branched alkylene group. The alkylene group preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and still more preferably 1 to 2 carbon atoms.
As the alkoxyalkyl group for Z, a group represented by the following general formula (VI) is particularly preferable.

In the formula (VI), R ⁴¹ is the same as described above, and R ⁴³ and R ⁴⁴ are each independently a linear or branched alkyl group or a hydrogen atom.
In R ⁴³ and R ⁴⁴ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group. In particular, it is preferable that one of R ⁴³ and R ⁴⁴ is a hydrogen atom and the other is a methyl group.

  Among these, as Z, a tertiary alkyl group-containing group is preferable, a group represented by the general formula (II) is more preferable, and a tert-butyloxycarbonyl group (t-boc) is most preferable.

In the general formula (a5-1), a is an integer of 1 to 3, b is an integer of 0 to 2, and a + b = 1 to 3.
a is preferably 1.
b is preferably 0.
a + b is preferably 1.
c is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.
d is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.
e is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.

  As the structural unit (a5), a structural unit represented by general formula (a5-1-1) or (a5-1-2) shown below is particularly desirable.

［式中、Ｒ，Ｚ，ｂ，ｃ，ｄ，ｅはそれぞれ前記と同じである。］

[Wherein R, Z, b, c, d and e are the same as defined above. ]

［式中、Ｒ，Ｚ，ａ，ｂ，ｃ，ｄ，ｅはそれぞれ前記と同じである。ｃ”は１〜３の整数である。］

[Wherein R, Z, a, b, c, d and e are the same as defined above. c ″ is an integer of 1 to 3.]

In the formula (a5-1-2), c ″ is an integer of 1 to 3, preferably 1 or 2, and more preferably 1.
When c in the formula (a5-1-2) is 0, the oxygen atom at the terminal of the carbonyloxy group (—C (═O) —O—) of the acrylate ester is bonded to the oxygen atom in the cyclic group. It is preferable that it is not bonded to the carbon atom. That is, when c is 0, there are two or more carbon atoms between the terminal oxygen atom and the oxygen atom in the cyclic group (the number of carbon atoms is 1 (that is, acetal bond and It is preferable that the above is excluded).

  The monomer for deriving the structural unit (a5) is, for example, a compound represented by the following general formula (a5-1 ′) (an acrylate ester containing an aliphatic cyclic group having 1 to 3 alcoholic hydroxyl groups). It can be synthesized by protecting a part or all of the hydroxyl groups with an organic group (preferably a tertiary alkyl group-containing group or an alkoxyalkyl group) using a known method.

［式中、Ｒ，Ｙ^５，ａ，ｂ，ｃ，ｄ，ｅはそれぞれ前記と同じである。］

[Wherein, R, Y ⁵ , a, b, c, d and e are the same as defined above. ]

As the structural unit (a5), one type of structural unit may be used alone, or two or more types of structural units may be used in combination.
The proportion of the structural unit (a5) in the component (A2-1) is preferably 1 to 45 mol%, and preferably 5 to 45 mol%, based on the total of all structural units constituting the component (A2-1). Is more preferably 5 to 40 mol%, and most preferably 5 to 35 mol%. By setting it as more than a lower limit, the solubility with respect to the organic solvent (S2) of a (A2-1) component improves, and the balance with another structural unit is favorable in it being below an upper limit.

(Structural unit (a6))
The structural unit (a6) is a structural unit represented by the following general formula (a6-1).

［式中、Ｒ^２０は水素原子又は炭素数１〜５のアルキル基であり；Ｒ^９は炭素数１〜５のアルキル基であり；ｉは１〜３の整数であり；ｚは０〜２の整数である。］

[Wherein, R ²⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; R ⁹ is an alkyl group having 1 to 5 carbon atoms; i is an integer of 1 to 3; z is 0 to 2] Is an integer. ]

In the formula (a6-1), as the alkyl group having 1 to 5 carbon atoms in R ²⁰ , specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl And linear or branched alkyl groups such as a group, a pentyl group, an isopentyl group, and a neopentyl group.
R ²⁰ is particularly preferably a hydrogen atom or a methyl group.

i is an integer of 1 to 3, preferably 1.
The bonding position of the hydroxyl group may be any of the o-position, m-position and p-position of the phenyl group. When i is 1, the p-position is preferred because it is readily available and inexpensive. When i is 2 or 3, arbitrary substitution positions can be combined.

z is an integer of 0-2. Of these, z is preferably 0 or 1, and particularly preferably 0 from an industrial viewpoint.
As the alkyl group for R ^9, the same alkyl groups as those for R ²⁰ can be used.
When z is 1, the substitution position of R ⁹ may be any of the o-position, m-position, and p-position. When z is 2, arbitrary substitution positions can be combined. At this time, the plurality of R ⁹ may be the same or different.

As the structural unit (a6), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a6) in the component (A2-1) is preferably 50 to 90 mol% with respect to the total of all the structural units constituting the component (A2-1), and is 55 to 85 mol%. More preferably, it is 60-80 mol%.
When the proportion of the structural unit (a6) is not less than the lower limit value of the range, the solubility of the component (A2-1) in the component (S2) is good, and when it is not more than the upper limit value of the range, other structural units And the balance is good.

(Structural unit (a7))
The structural unit (a7) is a structural unit represented by the following general formula (a7-1).

［式中、Ｒ^２０は前記と同じであり、Ｒ^７は炭素数１〜５のアルキル基であり、ｘは０〜３の整数である。］

[Wherein, R ²⁰ is the same as described above, R ⁷ is an alkyl group having 1 to 5 carbon atoms, and x is an integer of 0 to 3. ]

In the general formula ^{(A7-1), R 20} is the same as ^{R 20} in the general formula (a6-1).
In the formula (a7-1), examples of the alkyl group for R ⁷ include the same as the alkyl group for R ⁹ in the general formula (a6-1).
x is an integer of 0 to 3, preferably 0 or 1, and industrially particularly preferably 0.
When x is 1, the substitution position of R ⁷ may be any of the o-position, m-position and p-position of the phenyl group. When x is 2 or 3, any substitution position can be combined. At this time, the plurality of R ⁷ may be the same or different.
As the structural unit (a7), one type of structural unit may be used alone, or two or more types of structural units may be used in combination.
When the component (A2-1) has the structural unit (a7), the proportion of the structural unit (a7) is 10 to 50 mol% with respect to the total of all the structural units constituting the component (A2-1). It is preferably 15 to 45 mol%, more preferably 20 to 40 mol%.
When the proportion of the structural unit (a7) is not less than the lower limit of the range, the solubility of the component (A2-1) in the component (S2) can be controlled. Further, when a resist film is used, heat resistance and dry etching resistance are improved. When the amount is not more than the upper limit of the range, the balance with other structural units is good.

In the second resist material, the component (A2-1) is preferably a polymer compound having the structural unit (a1) and the structural unit (a5).
Examples of the component (A2-1) include a copolymer composed of the structural units (a1), (a2), (a3) and (a5).

As the component (A2-1), one type may be used alone, or two or more types may be used in combination.
As the component (A2-1), a copolymer containing the following combination of structural units is particularly preferable.

［式中、Ｒは上記と同じであり、複数のＲは相互に同じであっても異なっていてもよい。Ｒ^１１は式（ａ１−１−０１）におけるＲ^１１と同じである。Ｒ^２１〜Ｒ^２３は上記式（ＩＩ）におけるＲ^２１〜Ｒ^２３とそれぞれ同じであり、ｅは上記式（ａ５−１）におけるｅと同じである。］

[Wherein, R is the same as above, and a plurality of R may be the same or different from each other. R ¹¹ is the same as ^{R 11} in formula (a1-1-01). R ^{21 to} R ²³ are the same as R ^{21 to} R ²³ in the formula (II), respectively, and e is the same as e in the formula (a5-1). ]

The component (A2-1) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN). it can.
For the component (A2-1), a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination in the above polymerization. it may be introduced -C _{(CF 3)} 2 -OH group at the terminal. As described above, a copolymer introduced with a hydroxyalkyl group in which a part of hydrogen atoms of the alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing

The mass average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) in the component (A2-1) before purification is not particularly limited, preferably 1000 to 50000, more preferably 1500 to 30000, and 2000 to 20000. Is most preferred. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) in the component (A2-1) before purification is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. preferable.

[(A2-2) component]
When the second resist material is a “negative chemically amplified resist composition”, the component (A2) is a resin that is soluble in an alkali developer (hereinafter referred to as an alkali-soluble resin used in the second resist material). Is referred to as “(A2-2) component”).
In such a negative chemically amplified resist composition, it is preferable to use a crosslinking agent component (C) (component (C)) in addition to the component (A2-2) as a base component.
In the negative chemically amplified resist composition, when an acid is generated from an acid generator upon exposure, the acid acts to cause crosslinking between the component (A2-2) and the component (C), thereby causing alkali development. Changes to slightly soluble in liquid. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the negative chemically amplified resist composition on the substrate is selectively exposed, the exposed portion turns into poorly soluble in an alkaline developer. Since the unexposed area remains soluble in the alkali developer, the resist pattern can be formed by alkali development.

As a suitable component (A2-2), since it is excellent in solubility in the organic solvent (S2), for example, it is fluorinated represented by the general formula (a1-1-1) described later. Examples include alkali-soluble resins having a hydroxyalkyl group.
Specific examples of the alkali-soluble resin having a fluorinated hydroxyalkyl group include, for example, a structural unit (a1 ′) having an aliphatic cyclic group having a fluorinated hydroxyalkyl group in the main chain, and preferably And a polymer compound (A2-2-10) having a structural unit (a2 ′) having a hydroxyalkyl group (hereinafter referred to as “component (A2-2-10)”).
Examples of the alkali-soluble resin having a fluorinated hydroxyalkyl group include, for example, a structural unit (a1 ″) containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group, A constitutional unit (a2 ″) derived from an acrylic ester containing a hydroxyl group-containing aliphatic cyclic group and / or a constitution derived from acrylic acid having no cyclic structure and having an alcoholic hydroxyl group in the side chain And a polymer compound (A2-2-20) containing a unit (a3 ″) (hereinafter referred to as “component (A2-2-20)”).

.. About polymer compound (A2-2-10) The component (A2-2-10) has a structural unit (a1 ′) having an aliphatic cyclic group having a fluorinated hydroxyalkyl group in the main chain. .
In addition to the structural unit (a1 ′), the component (A2-2-10) further includes a structural unit (a2 ′) having a hydroxyalkyl group (hereinafter abbreviated as “structural unit (a2 ′)”). It is preferable to have.

... Constituent unit (a1 ') The component (A2-2-10) has a constituent unit (a1') having an aliphatic cyclic group having a fluorinated hydroxyalkyl group in the main chain.
In the structural unit (a1 ′), the “aliphatic cyclic group having a fluorinated hydroxyalkyl group” means that a fluorinated hydroxyalkyl group is bonded to the carbon atom constituting the ring of the aliphatic cyclic group. It means a bonded group.
Further, “having an aliphatic cyclic group in the main chain” means that at least one, preferably two or more carbon atoms on the ring of the aliphatic cyclic group are the component (A2-2-10) It means to constitute the main chain.
When the component (A2-2) contains the component (A2-2-10) having the structural unit (a1 ′), the solubility of the resist film in the alkaline developer is increased, and the resolution, resist pattern shape, Lithographic properties such as line edge roughness (LER) are improved. Further, by having an aliphatic cyclic group (for example, a structure of norbornane or tetracyclododecane) in the main chain, the carbon density is increased and the etching resistance is also improved.

Here, the “fluorinated hydroxyalkyl group” is a hydroxyalkyl group in which part of the hydrogen atoms of the alkyl group is substituted with a hydroxy group, and part or all of the remaining hydrogen atoms in the hydroxyalkyl group are It is substituted by a fluorine atom.
In the fluorinated hydroxyalkyl group, the hydrogen atom of the hydroxy group is easily released by fluorination.
In the fluorinated hydroxyalkyl group, the alkyl group is preferably a linear or branched alkyl group.
The number of carbon atoms of the alkyl group is not particularly limited, preferably 1 to 20, more preferably 4 to 16, and most preferably 4 to 12.
The number of hydroxy groups is not particularly limited, and is preferably one.
As the fluorinated hydroxyalkyl group, in particular, a fluorinated alkyl group and / or a fluorine atom is bonded to a carbon atom to which the hydroxy group is bonded (here, the α-position carbon atom of the hydroxyalkyl group). Is preferred.
Here, in the fluorinated alkyl group bonded to the α-position, it is preferable that all hydrogen atoms of the alkyl group are substituted with fluorine atoms. Moreover, as an alkyl group of this fluorinated alkyl group, a C1-C5 linear or branched alkyl group is preferable, and it is more preferable that it is C1.

“Aliphatic” in “aliphatic cyclic group having a fluorinated hydroxyalkyl group” is a relative concept with respect to aromaticity, and means a group or compound having no aromaticity. It is defined as The aliphatic cyclic group may be monocyclic or polycyclic.
“Monocyclic aliphatic cyclic group” means a monocyclic group having no aromaticity, and “polycyclic aliphatic cyclic group” means a polycyclic group having no aromaticity. Means a group.
In the structural unit (a1 ′), the aliphatic cyclic group is preferably polycyclic because it is excellent in etching resistance and the like.
An aliphatic cyclic group is a hydrocarbon group composed of carbon and hydrogen (alicyclic group), and a part of the carbon atoms constituting the ring of the alicyclic group is heterogeneous such as an oxygen atom, a nitrogen atom, a sulfur atom Heterocyclic groups and the like substituted with atoms are included. These aliphatic cyclic groups may have a substituent, and examples of the substituent include an alkyl group having 1 to 5 carbon atoms.
Here, “having a substituent” means that part or all of the hydrogen atoms bonded to the carbon atoms constituting the ring of the aliphatic cyclic group are substituted with a substituent (atom or group other than a hydrogen atom). Means that The aliphatic cyclic group is preferably an alicyclic group.
The aliphatic cyclic group may be either saturated or unsaturated, but is preferably saturated because it is highly transparent to ArF excimer laser and the like, and has excellent resolution and depth of focus (DOF). .
It is preferable that carbon number of an aliphatic cyclic group is 5-15.

Specific examples of the aliphatic cyclic group include the following.
Examples of the monocyclic group include groups in which two or more hydrogen atoms have been removed from cycloalkane. More specifically, groups obtained by removing two or more hydrogen atoms from cyclopentane and cyclohexane are exemplified.
Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane or the like. More specifically, a group in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like.
Such an aliphatic cyclic group can be appropriately selected and used from among many proposed resins for photoresist compositions for ArF excimer laser processes, for example.
Among these, a group obtained by removing two or more hydrogen atoms from cyclopentane, cyclohexane, adamantane, norbornane, and tetracyclododecane is preferable because it is easily available from an industrial viewpoint.
Among these exemplified alicyclic groups, a group obtained by removing three hydrogen atoms from norbornane or tetracyclododecane is preferable, as in the structural unit (a1′-1) described later, and in particular, three hydrogen atoms from norbornane. Groups other than are preferred.

  Preferred examples of the structural unit (a1 ′) include the structural unit (a1′-1) represented by the following general formula (a1′-1). By including the structural unit (a1′-1), solubility in an alkali developer is particularly improved. Also, lithography properties such as resolution are improved.

［式（ａ１’−１）中、Ｚ’はフッ素化されたヒドロキシアルキル基であり、ｒ”は０又は１である。］

[In the formula (a1′-1), Z ′ is a fluorinated hydroxyalkyl group, and r ″ is 0 or 1.]

  In formula (a1′-1), r ″ is 0 or 1, and is preferably 0 because it is easily available industrially.

In the formula (a1′-1), the “fluorinated hydroxyalkyl group” represented by Z ′ is the same as described above. Among them, Z ′ is particularly preferably a group represented by the following general formula (a1′-1-0) because it has excellent resist pattern shape and reduces line edge roughness (LER) and the like. .
“Line edge roughness (LER)” refers to uneven unevenness on the side wall of a line.

［式（ａ１’−１−０）中、Ｒ^１１”，Ｒ^１２”はそれぞれ独立して水素原子又は炭素原子数１〜５の低級アルキル基であり；ｍ”，ｎ”はそれぞれ独立して１〜５の整数であり、ｑは１〜５の整数である。］

[In formula (a1′-1-0), R ¹¹ ″ and R ¹² ″ each independently represents a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms; m ″ and n ″ each independently It is an integer of 1-5, q is an integer of 1-5. ]

In formula (a1′-1-0), R ¹¹ ″ and R ¹² ″ each independently represent a hydrogen atom or a lower alkyl group.
The lower alkyl group is preferably a linear or branched lower alkyl group having 5 or less carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a tert-butyl group. , A pentyl group, an isopentyl group, a neopentyl group, and the like, and a methyl group is preferable.
Among these, it is preferable that R ¹¹ ″ and R ¹² ″ are both hydrogen atoms.
q is an integer of 1 to 5, preferably an integer of 1 to 3, and most preferably 1.
m ″ and n ″ are each independently an integer of 1 to 5, preferably an integer of 1 to 3. In particular, it is preferable that m ″ and n ″ are both 1 because they are excellent in terms of synthesis.

As the structural unit (a1 ′), one type or a mixture of two or more types can be used.
The content ratio of the structural unit (a1 ′) in the component (A2-2-10) is preferably 50 to 90 mol% based on the total of all the structural units constituting the component (A2-2-10). -90 mol% is more preferable, and 60-80 mol% is further more preferable. By being more than the lower limit of the said range, the effect by containing a structural unit (a1 ') improves, and when it is below an upper limit, a balance with another structural unit becomes favorable.

... Constituent unit (a2 ') In addition to the constituent unit (a1'), the component (A2-2-10) preferably further comprises a constituent unit (a2 ') having a hydroxyalkyl group.
When the component (A2-2) has the component (A2-2-10) containing the structural unit (a2 ′), the solubility in an alkali developer is improved. In addition, the crosslinkability with the component (C) is increased, and the difference (contrast) in solubility between the exposed area and the unexposed area in the alkaline developer is increased, so that the negative resist can function more sufficiently.
Examples of the structural unit (a2 ′) include a structural unit (a210) having an aliphatic cyclic group having a hydroxyalkyl group in the main chain, and a structural unit (a220) derived from an acrylate ester having a hydroxyl group-containing alkyl group. Etc.) are preferably used.

... About structural unit (a210) A structural unit (a210) says the structural unit which has the aliphatic cyclic group which has a hydroxyalkyl group in a principal chain.
As the structural unit (a210), in the “fluorinated hydroxyalkyl group” of the structural unit (a1 ′), a non-fluorinated hydroxyalkyl group, that is, a part of hydrogen atoms of the alkyl group is substituted with a hydroxy group. The structural unit similar to the structural unit (a1 ′) is preferable except that the remaining hydrogen atom in the hydroxyalkyl group is not substituted by a fluorine atom.
Preferred examples of the structural unit (a210) include a structural unit represented by the following general formula (a2′-1) (hereinafter referred to as “structural unit (a2′-1)”). By including the structural unit (a2′-1), lithography properties such as resolution, resist pattern shape, and line width roughness (LWR) are improved. In addition, good contrast is easily obtained and etching resistance is improved.

［式（ａ２’−１）中、Ｒ^１３”、Ｒ^１４”はそれぞれ独立して水素原子又は炭素原子数１〜５の低級アルキル基であり、Ｙ’は水素原子又はヒドロキシアルキル基であり、ｒは０又は１であり、ｐは１〜３の整数である。］

[In the formula (a2′-1), R ¹³ ″ and R ¹⁴ ″ are each independently a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, Y ′ is a hydrogen atom or a hydroxyalkyl group, r is 0 or 1, and p is an integer of 1 to 3. ]

The structural unit (a2′-1) represented by the general formula (a2′-1) is a structural unit having a norbornane or tetracyclododecane structure having a hydroxyalkyl group in the main chain.
In formula (a2′-1), R ¹³ ″ and R ¹⁴ ″ each independently represent a hydrogen atom or a lower alkyl group. As the lower alkyl group, the same as the lower alkyl groups represented by R ¹¹ ″ and R ¹² ″ in formula (a1′-1-1) can be exemplified. Among these, it is preferable that R ¹³ ″ and R ¹⁴ ″ are both hydrogen atoms.
Y ′ is a hydrogen atom or a hydroxyalkyl group.
The hydroxyalkyl group is preferably a linear or branched hydroxyalkyl group having 10 or less carbon atoms, more preferably a linear or branched hydroxyalkyl group having 8 or less carbon atoms. Preferably, it is a C1-C3 linear lower hydroxyalkyl group.
The number of hydroxyl groups and the bonding position in the hydroxyalkyl group are not particularly limited and are usually one and preferably bonded to the terminal of the alkyl group.
Y ′ is particularly preferably a hydrogen atom.
r is 0 or 1, and 0 is preferable.
p is an integer of 1 to 3, preferably 1 or 2, and most preferably 1.

  Specific examples of the structural unit (a2′-1) include the following chemical formulas (a2′-1-1) to (a2′-1-7).

Among these, the above chemical formulas (a2′-1-1), (a2′-1-2), and (a2′-1-3) are preferable.
The structural unit (a210) can be used alone or in combination of two or more.
The content ratio of the structural unit (a210) in the component (A2-2-10) is preferably 10 to 50 mol% with respect to the total of all the structural units constituting the component (A2-2-10). 50 mol% is more preferable and 20-45 mol% is further more preferable. By being more than the lower limit of the above range, the effect of containing the structural unit (a210) such that alkali solubility is improved and good contrast is easily obtained is improved. On the other hand, the balance with other structural units becomes favorable by being below an upper limit.

··· Constituent Unit (a220) The constituent unit (a220) is a constituent unit derived from an acrylate ester having a hydroxyl group-containing alkyl group.

When the structural unit (a220) is a structural unit having a hydroxyl group-containing cyclic alkyl group (hereinafter, this structural unit is abbreviated as “structural unit (a221)”), the swelling suppression effect of the resist pattern is enhanced. Also, the resolution is improved. Furthermore, good contrast and etching resistance are easily obtained.
As the structural unit (a221), for example, description of “structural unit (a2 ″) derived from an acrylate ester containing a hydroxyl group-containing aliphatic cyclic group” that constitutes the component (A2-2-20) described later. Among the structural units exemplified in, those in which the aliphatic cyclic group is a saturated hydrocarbon group can be mentioned. Among them, the substituent bonded to the α-position of the acrylate ester is particularly preferably a fluorinated alkyl group, and most preferably a trifluoromethyl group (—CF ₃ ).

In the case where the structural unit (a220) is a structural unit having a hydroxyl group-containing chain alkyl group (hereinafter, this structural unit is abbreviated as “structural unit (a222)”), the hydrophilicity of the entire component (A2-2-10) Therefore, the solubility in an alkali developer is increased, and the resolution is improved. Further, the controllability of the crosslinking reaction during the formation of the resist pattern becomes good, and the pattern shape and resolution are improved. Further, the film density tends to be improved, whereby the film loss during etching can be suppressed and the heat resistance tends to be improved.
As the structural unit (a222), for example, a “constituent unit derived from acrylic acid having no cyclic structure and having an alcoholic hydroxyl group in the side chain” constitutes the component (A2-2-20) described later. Among the structural units exemplified in the description of (a3 ″) ”, those having a hydroxyalkyl group can be mentioned. Of these, those having a hydroxyalkyl group in the ester portion of the acrylate ester are preferred, and those in which the substituent bonded to the α-position of the acrylate ester is a fluorinated alkyl group are particularly preferred. Most preferred is the group (—CF ₃ ).

The structural unit (a220) can be used alone or in combination of two or more.
The content ratio of the structural unit (a220) in the component (A2-2-10) is preferably 10 to 80 mol% with respect to the total of all the structural units constituting the component (A2-2-10). 60 mol% is more preferable and 20-55 mol% is further more preferable. The effect by containing a structural unit (a220) is acquired by being more than the lower limit of the said range, and a balance with another structural unit becomes favorable by being below an upper limit.

In the case where the structural unit (a220) includes both the structural unit (a221) and the structural unit (a222), the mixing ratio of both is a molar ratio, that is, the structural unit (a221): the structural unit (a222) = It is preferably 9: 1 to 1: 9, more preferably 8: 2 to 2: 8, and even more preferably 6: 4 to 7: 3.
A good exposure margin can be obtained by blending the structural unit (a221) and the structural unit (a222) in a balanced manner at the mixing ratio. Moreover, a moderate contrast is obtained and the resolution is improved. Furthermore, etching resistance is also improved.

... Other structural units The component (A2-2-10) is a resin known as a conventional chemical amplification resist composition as a structural unit other than the structural units (a1 ′) and (a2 ′). The structural unit used for the component can be appropriately used.
Among them, the component (A2-2-10) is preferably a polymer compound having the structural unit (a1 ′) and the structural unit (a2 ′), and the structural units (a1 ′) and (a2 ′). It is more preferable that the polymer compound has a main component.

Here, the “principal component” means that the total ratio of the structural unit (a1 ′) and the structural unit (a2 ′) is 70 with respect to the total of all structural units constituting the component (A2-2-10). It means to occupy at least mol%, more preferably at least 80 mol%, and may be 100 mol%. Among them, the component (A2-2-10) is most preferably a polymer compound composed of the structural unit (a1 ′) and the structural unit (a2 ′).
The combination of the structural unit (a1 ′) and the structural unit (a2 ′) in the component (A2-2-10) is preferably a combination of the structural unit (a1 ′) and the structural unit (a210).
As (A2-2-10) component, what contains the combination of the structural unit represented, for example by following chemical formula (A2-2-11)-(A2-2-14) is mentioned preferably.

  Among the above, the component (A2-2-10) is at least one selected from the group consisting of combinations of structural units represented by the chemical formulas (A2-2-11) to (A2-2-14). The polymer compound containing the combination of these is preferable, and the polymer compound containing the combination of the structural unit represented by the said Chemical formula (A2-2-11) is the most preferable.

The mass average molecular weight (Mw; polystyrene conversion value by gel permeation chromatography) in the component (A2-2-10) before purification is preferably 2000 to 10,000, more preferably 3000 to 6000, and more preferably 3000 to 3,000. It is particularly preferably 5000.
A favorable contrast can be obtained by being more than the lower limit of the said range, and swelling of a resist pattern can be suppressed by being below an upper limit. As a result, the resolution is improved. Further, since the swelling of the pattern can be suppressed, the effect of improving the depth of focus (DOF) characteristic and the effect of suppressing the line edge roughness (LER) can be obtained. Moreover, it is preferable to make the said mass mean molecular weight into this range from the point that the swelling suppression effect of a resist pattern is also high. When the mass average molecular weight is lower within this range, good characteristics tend to be obtained.
Further, the dispersity (Mw / Mn) in the component (A2-2-10) before purification is preferably 1.0 to 5.0, and more preferably 1.0 to 2.5.

When the component (A2-2) is used, one or more of the above components (A2-2-10) can be mixed and used.
However, when the component (A2-2-10) is used, the proportion of the component (A2-2-10) contained in the component (A2-2) is preferably 40% by mass or more, and 50% by mass or more. It is more preferable that it is 60 mass% or more.

.. About polymer compound (A2-2-20) The component (A2-2-20) includes a structural unit (a1 ″) containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group.
In addition to the structural unit (a1 ″), the component (A2-2-20) further includes a structural unit (a2 ″) derived from an acrylate ester containing a hydroxyl group-containing aliphatic cyclic group. preferable.
In addition to the structural unit (a1 ″) or the structural unit (a1 ″) and the structural unit (a2 ″), the component (A2-2-20) does not have a cyclic structure. And a structural unit (a3 ″) derived from acrylic acid having an alcoholic hydroxyl group in the side chain.

... Structural Unit (a1 ") The structural unit (a1") is a structural unit containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group. By including the structural unit (a1 ″), solubility in an alkaline developer is improved. Further, swelling of the resist pattern is suppressed, and lithography properties such as resolution, pattern shape, and LWR are improved.

The aliphatic cyclic group having a fluorinated hydroxyalkyl group is the same as that exemplified in the description of the structural unit (a1 ′), and the aliphatic cyclic group (the fluorinated hydroxyalkyl group is bonded). Among these, a group in which two hydrogen atoms have been removed from cyclohexane, adamantane, norbornane, or tetracyclododecane is particularly preferable because it is easily available in the industry.
Of these exemplified monocyclic groups and polycyclic groups, groups in which two hydrogen atoms have been removed from norbornane are particularly preferred.

  The structural unit (a1 ″) is preferably a structural unit derived from acrylic acid, and in particular, an oxygen atom (—O— at the terminal of the carbonyloxy group [—C (═O) —O—] of the acrylate ester. A structure in which the aliphatic cyclic group is bonded to-) (a structure in which a hydrogen atom of a carboxy group of acrylic acid is substituted with the aliphatic cyclic group) is preferable.

  More specifically, the structural unit (a1 ″ -1) represented by the following general formula (1) is preferable as the structural unit (a1 ″).

［式（１）中、Ｒは水素原子、低級アルキル基、又はハロゲン化低級アルキル基であり；ｕ、ｔ、ｔ”はそれぞれ独立して１〜５の整数である。］

[In Formula (1), R is a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group; u, t, and t ″ are each independently an integer of 1 to 5.]

In formula (1), R is a hydrogen atom, a lower alkyl group, or a halogenated lower alkyl group.
The lower alkyl group or halogenated alkyl group of R is the same as the lower alkyl group or halogenated alkyl group that may be bonded to the α-position of the acrylate ester.
R is preferably a hydrogen atom or a lower alkyl group, and more preferably a hydrogen atom or a methyl group in terms of industrial availability.
u is each independently an integer of 1 to 5, preferably an integer of 1 to 3, and most preferably 1.
t is an integer of 1 to 5, preferably an integer of 1 to 3, and most preferably 1.
t ″ is an integer of 1 to 5, preferably an integer of 1 to 3, more preferably an integer of 1 to 2, and most preferably 1.
In the structural unit (a1 ″ -1) represented by the general formula (1), a 2-norbornyl group or a 3-norbornyl group is bonded to the carboxy group of (α-lower alkyl) acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

As the structural unit (a1 ″), one type or a mixture of two or more types can be used.
The content ratio of the structural unit (a1 ″) in the component (A2-2-20) is preferably 10 to 90 mol% based on the total of all the structural units constituting the component (A2-2-20). -90 mol% is more preferable, 40-90 mol% is especially preferable, and 45-85 mol% is the most preferable. By being more than the lower limit of the said range, the effect by containing a structural unit (a1 '') is obtained. By being obtained and being not more than the upper limit value, the balance with other structural units is good.

... Constituent unit (a2 ") In addition to the constituent unit (a1"), the component (A2-2-20) is a constituent unit derived from an acrylate ester further containing a hydroxyl group-containing aliphatic cyclic group ( a2 ″).
When the component (A2-2-20) containing the structural unit (a2 ″) is blended with the negative chemically amplified resist composition, the hydroxyl group (alcoholic hydroxyl group) of the structural unit (a2 ″) becomes the component (B). It reacts with the component (C) by the action of the acid generated from the component, whereby the component (A2-2-20) changes from a property soluble in an alkali developer to an insoluble property.

A “hydroxyl group-containing aliphatic cyclic group” is a group in which a hydroxyl group is bonded to an aliphatic cyclic group.
The number of hydroxyl groups bonded to the aliphatic cyclic group is preferably 1 to 3, and more preferably 1.
The aliphatic cyclic group may be monocyclic or polycyclic, but is preferably a polycyclic group. Moreover, it is preferable that it is an alicyclic hydrocarbon group. Moreover, it is preferable that it is saturated. Moreover, it is preferable that carbon number of an aliphatic cyclic group is 5-15.
Specific examples of the aliphatic cyclic group (the state before the hydroxyl group is bonded) include those similar to the aliphatic cyclic group of the structural unit (a1 ″).
As the aliphatic cyclic group of the structural unit (a2 ″), among them, a cyclohexyl group, an adamantyl group, a norbornyl group, and a tetracyclododecyl group are preferable because they are industrially available. Among them, a cyclohexyl group and an adamantyl group are preferable. A group is more preferable, and an adamantyl group is particularly preferable.
In addition to the hydroxyl group, a linear or branched alkyl group having 1 to 4 carbon atoms may be bonded to the aliphatic cyclic group.

In the structural unit (a2 ″), the hydroxyl group-containing aliphatic cyclic group is preferably bonded to the terminal oxygen atom of the ester group (—C (═O) —O—) of the acrylate ester.
In this case, in the structural unit (a2 ″), another substituent may be bonded to the α-position (α-position carbon atom) of the acrylate ester instead of the hydrogen atom. Preferably, a lower alkyl group or a halogenated lower alkyl group is used.
These explanations are the same as those of R in the general formula (1) of the structural unit (a1 ″), and among those which can be bonded to the α-position, preferred is a hydrogen atom or a lower alkyl group. In particular, a hydrogen atom or a methyl group is preferable.

  As a specific example of the structural unit (a2 ″), for example, a structural unit (a2 ″ -1) represented by the following general formula (2) is preferable.

［式（２）中、Ｒは前記と同じであり；Ｒ^６は水素原子、低級アルキル基、または炭素数１〜５のアルコキシ基であり；ｒ’は１〜３の整数である。］

[In Formula (2), R is the same as the above; R ⁶ is a hydrogen atom, a lower alkyl group, or an alkoxy group having 1 to 5 carbon atoms; and r ′ is an integer of 1 to 3. ]

R is the same as the description of R in the general formula (1).
The lower alkyl group for R ⁶ is the same as the lower alkyl group for R.
In the general formula (2), R and R ⁶ are most preferably hydrogen atoms.
r ′ is an integer of 1 to 3, and is preferably 1.
The bonding position of the hydroxyl group is not particularly limited, but is preferably bonded to the position of the 3rd position of the adamantyl group.

As the structural unit (a2 ″), one type or a mixture of two or more types can be used.
The proportion of the structural unit (a2 ″) in the component (A2-2-20) is preferably 10 to 70 mol% based on the total of all structural units constituting the component (A2-2-20). 50 mol% is more preferable, and 20-40 mol% is still more preferable. By being more than the lower limit of the said range, the effect by containing a structural unit (a2 '') will be acquired, and when it is below an upper limit. The balance with other structural units is good.

... About the structural unit (a3 ") In addition to the structural unit (a1"), or the component (A2-2-20), in addition to the structural unit (a1 ") and the structural unit (a2"), It preferably has a structural unit (a3 ″) derived from acrylic acid having no cyclic structure and having an alcoholic hydroxyl group in the side chain.
When the component (A2-2-20) containing the structural unit (a3 ″) is blended with the negative chemically amplified resist composition, the alcoholic hydroxyl group of the structural unit (a3 ″) becomes a component of the structural unit (a2 ″). Along with the hydroxyl group, it reacts with the component (C) by the action of the acid generated from the component (B).
Therefore, the component (A2-2-20) easily changes from a soluble property to an insoluble property with respect to an alkaline developer, and an effect of improving lithography properties such as resolution can be obtained. Moreover, film loss can be suppressed. Moreover, the controllability of the crosslinking reaction during pattern formation is improved. Furthermore, the film density tends to improve. Thereby, there exists a tendency for heat resistance to improve. Furthermore, etching resistance is also improved.

In the structural unit (a3 ″), “having no cyclic structure” means having no aliphatic cyclic group or aromatic group.
The structural unit (a3 ″) is clearly distinguished from the structural unit (a2 ″) by not having a cyclic structure.
Examples of the structural unit having an alcoholic hydroxyl group in the side chain include a structural unit having a hydroxyalkyl group.
Examples of the hydroxyalkyl group include those similar to the hydroxyalkyl group in the “fluorinated hydroxyalkyl group” of the structural unit (a1 ″).
For example, the hydroxyalkyl group may be directly bonded to the α-position carbon atom of the main chain (the portion where the ethylenic double bond of acrylic acid is cleaved), or may be substituted with the hydrogen atom of the carboxy group of acrylic acid. You may comprise ester.
In the structural unit (a3 ″), it is preferable that at least one or both of them be present.
When no hydroxyalkyl group is bonded to the α-position, a lower alkyl group or a halogenated lower alkyl group may be bonded to the α-position carbon atom instead of a hydrogen atom.
About these, it is the same as that of description of R in General formula (1).

  As the structural unit (a3 ″), structural units (a3 ″ -1) represented by the following general formula (3) are preferable.

［式（３）中、Ｒ^３は水素原子、低級アルキル基、ハロゲン化低級アルキル基、またはヒドロキシアルキル基であり；Ｒ^４は、水素原子、アルキル基、またはヒドロキシアルキル基であり、かつＲ^３、Ｒ^４の少なくとも一方はヒドロキシアルキル基である。］

[In Formula (3), R ³ is a hydrogen atom, a lower alkyl group, a halogenated lower alkyl group, or a hydroxyalkyl group; R ⁴ is a hydrogen atom, an alkyl group, or a hydroxyalkyl group, and R ³ , R ⁴ is a hydroxyalkyl group. ]

The hydroxyalkyl group in R ³ is preferably a hydroxyalkyl group having 10 or less carbon atoms, more preferably a linear or branched chain, and a hydroxyalkyl group having 2 to 8 carbon atoms. More preferred is a hydroxymethyl group or a hydroxyethyl group.
The number of hydroxyl groups and the bonding position are not particularly limited and are usually one and preferably bonded to the terminal of the alkyl group.
The lower alkyl group for R ³ is preferably an alkyl group having 10 or less carbon atoms, more preferably an alkyl group having 2 to 8 carbon atoms, and most preferably an ethyl group or a methyl group.
The halogenated lower alkyl group for R ³ is preferably a lower alkyl group having 5 or less carbon atoms (preferably an ethyl group or a methyl group), and part or all of the hydrogen atoms are halogen atoms (preferably fluorine atoms). A group substituted with
Examples of the alkyl group and hydroxyalkyl group in R ⁴ include the same as the lower alkyl group and hydroxyalkyl group of R ³ .

As the structural unit (a3 ″ -1) represented by the general formula (3), specifically, a structural unit derived from α- (hydroxyalkyl) acrylic acid (here, derived from an acrylate ester) A structural unit derived from an α- (hydroxyalkyl) acrylic acid alkyl ester, and a structural unit derived from an (α-alkyl) acrylic hydroxyalkyl ester.
Among these, when the structural unit (a3 ″) includes a structural unit derived from an α- (hydroxyalkyl) acrylic acid alkyl ester, it is preferable from the viewpoint of improving the film density, and among them, α- (hydroxymethyl)- Structural units derived from acrylic acid ethyl ester or α- (hydroxymethyl) -acrylic acid methyl ester are preferred.
In addition, it is preferable that the structural unit (a3 ″) includes a structural unit derived from (α-alkyl) acrylic acid hydroxyalkyl ester in terms of crosslinking efficiency. Among them, α-methyl-acrylic acid hydroxyethyl ester or α -Structural units derived from methyl-hydroxymethyl ester of acrylic acid are preferred.

As the structural unit (a3 ″), one type or a mixture of two or more types can be used.
The proportion of the structural unit (a3 ″) in the component (A2-2-20) is preferably 5 to 50 mol% with respect to the total of all structural units constituting the component (A2-2-20). 40 mol% is more preferable, 5 to 30 mol% is particularly preferable, and 10 to 25 mol% is most preferable. The effect by containing the structural unit (a3 ″) is obtained by being not less than the lower limit of the above range. Therefore, the balance with other structural units becomes good by being below the upper limit.

... Other structural units The component (A2-2-20) may have other structural units copolymerizable as structural units other than the structural units (a1 ″) to (a3 ″). Good.
As such other structural units, structural units conventionally used for known resin components for chemically amplified resist compositions can be used, for example, derived from acrylate esters containing a lactone-containing monocyclic or polycyclic group. Structural unit (a4 ″).
The structural unit (a4 ″) is not particularly limited, and any unit can be used. Specifically, as the lactone-containing monocyclic group, one hydrogen atom is removed from γ-butyrolactone. Examples of the lactone-containing polycyclic group include groups obtained by removing one hydrogen atom from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.
As the structural unit (a4 ″), one type or a mixture of two or more types can be used.
When the structural unit (a4 ″) is contained in the component (A2-2-20), the proportion of the structural unit (a4 ″) in the component (A2-2-20) is the component (A2-2-20). 10-70 mol% is preferable with respect to the sum total of all the structural units to perform, 10-40 mol% is more preferable, and 10-25 mol% is the most preferable. By being more than the lower limit of the said range, the effect by containing a structural unit (a4 '') will be acquired, and a balance with another structural unit will become favorable by being below an upper limit.

However, the component (A2-2-20) is particularly preferably a polymer compound containing the structural units (a1 ″) to (a3 ″) as main components.
The “main component” here means that the total of the structural units (a1 ″) to (a3 ″) occupies 50 mol% or more, preferably 70 mol% or more, more preferably 80 mol%. That's it. Most preferably, the component (A2-2-20) is a polymer compound composed of the structural unit (a1 ″), the structural unit (a2 ″) and the structural unit (a3 ″).

  As the component (A2-2-20), a component containing a combination of structural units such as the following formula (A2-2-21) is particularly preferable.

［式中、Ｒは前記と同じである。複数のＲはそれぞれ同じであっても異なっていてもよい。］

[Wherein, R is the same as defined above. A plurality of R may be the same or different. ]

The mass average molecular weight (Mw) in the component (A2-2-20) before purification is preferably 2000 to 30000, more preferably 2000 to 10000, and further preferably 3000 to 8000. By setting it within this range, a good dissolution rate in an alkaline developer can be obtained, which is preferable from the viewpoint of high resolution. When the mass average molecular weight is lower within this range, good characteristics tend to be obtained.
In addition, the dispersity (Mw / Mn) in the component (A2-2-20) before purification is preferably 1.0 to 5.0, and more preferably 1.0 to 2.5.

When the component (A2-2) is used, one or more of the above components (A2-2-20) can be mixed and used.
However, when the component (A2-2-20) is used, the proportion of the component (A2-2-20) contained in the component (A2-2) is preferably 40% by mass or more, and 50% by mass or more. It is more preferable that it is 60 mass% or more.

  Either the component (A2-2-10) or the component (A2-2-20) is radically polymerized by, for example, a method described in, for example, International Publication No. 2004/076495, a monomer for deriving each constituent unit by a conventional method. It can be synthesized by a method or the like.

(A2-2) A component may be used individually by 1 type and may use 2 or more types together.
In addition to the (A2-2-10) component and the (A2-2-20) component, the (A2-2) component includes other polymer compounds (hydroxystyrene) used in conventional negative resist compositions. Resin, novolac resin, acrylic resin, etc.) can also be used.

  In the second resist material, the content of the component (A2) may be adjusted according to the resist film thickness to be formed.

<(S2) component>
The component (S2) may be any component that dissolves the component (A2) and does not dissolve the component (A1), and can prepare the second resist material as a uniform solution. It is preferably at least one selected from the group consisting of alcohol-based organic solvents, fluorine-based organic solvents, and ether-based organic solvents that do not have a hydroxyl group. Alcohol-based organic solvents are particularly preferred because of their good stability.
(S2) Alcohol-based organic solvents, fluorine-based organic solvents, and ether-based organic solvents that do not have a hydroxyl group as the component are the alcohol-based organic solvent, fluorine-based organic solvent, and hydroxyl group in the description of the component (W). It is the same as the ether-based organic solvent that does not have any.
(S2) A component may be used independently and may be used as 2 or more types of mixed solvents.
The amount of the component (S2) used is not particularly limited, is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. In general, the solid content concentration of the second resist material Is used in a range of 0.5 to 20% by mass, preferably 1 to 15% by mass.

  The second resist material further includes miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coatability, dissolution inhibitors, plasticizers, Stabilizers, colorants, antihalation agents, dyes, and the like can be added as appropriate.

≪Resin purification method≫
The “resin purification method” of the present invention is a method of purifying the resin (A1) by the above-described resist pattern forming method of the present invention, and the resin (A1) blended in the first resist material, This is the same as the method of washing with a washing solution containing an organic solvent (W) that does not dissolve the resin (A1) and dissolves the resin (A2). Specifically, for example, the above-described purification methods (1) to (3) can be mentioned.

As shown in FIG. 1 described later, the purified product of the resin (A1) has a higher molecular weight than before purification. This is thought to be because impurities such as unreacted monomers and low molecular weight substances contained in the resin (A1) are removed by washing the resin (A1) with a washing solution containing an organic solvent (W). It is done.
In the double patterning process, when the second resist material is applied onto the support on which the first resist pattern is formed, the presence of the impurities contained in the first resist pattern Since the solubility of the first resist pattern in the organic solvent (S2) blended in is increased, the first resist pattern is reduced in film thickness and the like, and the resist pattern shape and lithography characteristics are deteriorated. Guessed.
In the present invention, since the impurities are previously removed from the resin (A1) by washing the resin (A1) with the cleaning liquid, the organic solvent mixed in the resist material used for the second and subsequent patterning is added to the organic solvent. One resist pattern is difficult to dissolve. Therefore, according to the resist pattern forming method of the present invention, it is possible to form a resist pattern that is not easily affected by the second and subsequent patterning. Thus, film loss is suppressed, and a resist pattern having a good resist pattern shape and lithography characteristics is formed.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

<Purification of resin>
The resins of Comparative Examples 1 and 2 are resins obtained by the following synthesis method.
The resins of Examples 1 to 4 are purified polymer compounds treated by the purification method shown below. However, Examples 3 and 4 are reference examples.

(Comparative Examples 1 and 2)
In a three-necked flask connected with a thermometer and a reflux tube, the following monomers (1) to (3) are dissolved in PGMEA, and further dimethyl azobisisobutyrate (V-601) is added and dissolved as a polymerization initiator. It was. This was dropped and polymerized in PGMEA heated to 80 ° C. over 1 hour in a nitrogen atmosphere, and then reprecipitation purification was performed using methanol to obtain a structure represented by the following chemical formula (A1-1-11). Resin (1) and Resin (2) were obtained.
Standard polystyrene equivalent weight average molecular weight (Mw), molecular weight dispersity (Mw / Mn) determined by GPC measurement, and copolymer composition ratio determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) (in the chemical formula) Table 1 below shows the ratio (molar ratio) of each structural unit.

Example 1
30 g of the resin (1) was dissolved in 90 g of methyl ethyl ketone (MEK). Subsequently, this MEK solution was added dropwise to 600 g of 1-butoxy-2-propanol (PGB). Thereafter, the precipitated white powder was filtered off and dried to obtain a purified polymer compound 1 as a target product.
With respect to this purified polymer compound 1, the weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 10500, and the molecular weight dispersity (Mw / Mn) was 1.44. The copolymer composition ratio (ratio of each structural unit in the chemical formula (molar ratio)) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) was a2 / a1 / a3 = 51.5 / 30. 7 / 17.8.

(Example 2)
30 g of the resin (1) was dissolved in 90 g of methyl ethyl ketone (MEK). Next, this MEK solution was added dropwise to a mixed solvent of 540 g of 1-butoxy-2-propanol (PGB) and 60 g of PGMEA. Thereafter, the precipitated white powder was filtered off and dried to obtain a purified polymer compound 2 as a target product.
With respect to this purified polymer compound 2, the standard polystyrene equivalent weight average molecular weight (Mw) determined by GPC measurement was 11000, and the molecular weight dispersity (Mw / Mn) was 1.44. The copolymer composition ratio (ratio of each structural unit in the chemical formula (molar ratio)) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is a2 / a1 / a3 = 52.5 / 29 8 / 17.7.

(Example 3)
To 30 g of the resin (1), 540 g of 1-butoxy-2-propanol (PGB) and 60 g of PGMEA were added and stirred for 30 minutes. Thereafter, the white powder was filtered off and dried to obtain the purified polymer compound 3 as the target product.
With respect to this purified polymer compound 3, the mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 7600, and the molecular weight dispersity (Mw / Mn) was 1.54. The copolymer composition ratio (ratio of each structural unit in the chemical formula (molar ratio)) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is a2 / a1 / a3 = 49.0 / 32 0.7 / 18.3.

Example 4
To 30 g of the resin (1), 540 g of 1-butoxy-2-propanol (PGB), 60 g of PGMEA, and 90 g of MEK were added and stirred for 30 minutes. Thereafter, the white powder was filtered and dried to obtain a purified polymer compound 4 which was the target product.
With respect to this purified polymer compound 4, the mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 8,000, and the molecular weight dispersity (Mw / Mn) was 1.55. Further, the copolymer composition ratio (ratio (molar ratio) of each structural unit in the chemical formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is a2 / a1 / a3 = 49.4 / 32 4 / 18.2.

Table 1 shows the proportion (molar ratio) of the structural units, the mass average molecular weight (Mw), and the molecular weight dispersity (Mw / Mn) in the resin of each example.
Moreover, the chromatogram measured by the gel permeation chromatography (GPC) about the high molecular compound of the comparative example 1 and the high molecular compound which performed the purification method of Example 1, 2 is shown in FIG.

From Table 1 and FIG. 1, it can be seen that the purified polymer compounds 1 and 2 purified by the purification method of Examples 1 and 2 are higher in molecular weight than the untreated resin (1) of Comparative Example 1. .
It can also be seen that the purified polymer compounds 3 and 4 purified by the purification methods of Examples 3 and 4 also have a higher molecular weight than the untreated resin (1) of Comparative Example 1.
From the comparison of Examples 1 to 4, the resin solution (liquid) once dissolved in the organic solvent (S1) was dropped into the organic solvent (W) and washed, and the resin itself (solid) was washed with the organic solvent (W). It can be seen that the polymer has a higher molecular weight than that obtained by dispersing and washing. This is considered because the resin solution (liquid) is more uniformly washed.

<Preparation of first resist material>
Each component shown in Table 2 was mixed and dissolved to prepare a positive chemically amplified resist composition as a first resist material.

Each abbreviation in Table 2 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(A1) -1: the resin (1).
(A1) -2: the resin (2).
(A1) -3: The purified polymer compound 1.
(A1) -4: The purified polymer compound 2.
(A1) -5: The purified polymer compound 3.
(A1) -6: The purified polymer compound 4.
(B) -1: An acid generator comprising a compound represented by the following chemical formula (B1).
(B) -2: An acid generator composed of a compound represented by the following chemical formula (B2).

(D) -1: tri-n-pentylamine.
(E) -1: salicylic acid.
(S) -1: Mixed solvent of PGMEA and PGME (PGMEA: PGME = 6: 4 (mass ratio)).

<Evaluation of film reduction with resist film>
The first resist material is applied onto an 8-inch silicon wafer using a spinner, hard-baked on a hot plate at 150 ° C. for 60 seconds, and dried to obtain a resist having a thickness of 90 nm. A film (first resist film) was formed.
Next, 3 g of 1-butoxy-2-propanol (PGB) was dropped on the entire surface of the first resist film and allowed to stand for 60 seconds.
Thereafter, spin-drying is performed by spin coating, and the film thickness of the first resist film is measured by using Nanospec 6100A (manufactured by Nanometrics), and film reduction evaluation in the resist film is performed based on the following criteria. Went. The results are shown in Table 3.
(Standard)
(Double-circle): The film reduction from the initial film thickness of 90 nm was hardly recognized.
A: The amount of film reduction from the initial film thickness of 90 nm was less than 3 nm.
X: The amount of film reduction from the initial film thickness of 90 nm was 3 nm or more.

From the results of Table 3, it was confirmed that in Test Examples 3 to 6 using the resist materials (3) to (6) containing a previously purified resin, the occurrence of film reduction was suppressed.
From the comparison between Test Example 2 and Test Examples 3 and 4, it can be seen that the occurrence of film reduction is not mainly due to the mass average molecular weight of the resin.
From the comparison of Test Examples 3 to 6, it can be seen that once the resin is dissolved and purified, the occurrence of film loss is further suppressed.

<Formation of resist pattern>
An organic antireflection film composition “ARC95” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto an 8-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to be dried. Thereby, an organic antireflection film having a thickness of 90 nm was formed.
On the organic antireflection film, the resist materials (1), (3) and (4) are respectively applied using a spinner, and pre-baked (PAB) at 120 ° C. for 60 seconds on a hot plate. By drying, a resist film (first resist film) having a film thickness of 100 nm was formed.
Next, a protective film-forming coating solution “TILC-057” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto each of the first resist films using a spinner, and is heated at 90 ° C. for 60 seconds. By heating, a top coat having a film thickness of 35 nm was formed.
Next, an ArF exposure apparatus NSR-S609B (Nikon Corp .; NA (numerical aperture) = 1.07, Dipole (0.78 / 0.97)) is applied to the first resist film on which the top coat is formed. The ArF excimer laser is applied to the first resist film through a photomask (6% halftone) targeting a line-and-space resist pattern (L / S pattern) with a line width of 50 nm / pitch of 100 nm. (193 nm) was selectively irradiated.
Then, a post-exposure heating (PEB) treatment was performed at 110 ° C. for 60 seconds, and a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution “NMD-3” (trade name, Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C. For 10 seconds.
As a result, an L / S pattern in which lines with a width of 50 nm were arranged at equal intervals (pitch of 100 nm) was formed on the first resist film. The optimum exposure dose Eop (mJ / cm ² , sensitivity) in forming the L / S pattern was determined. The results are shown in Table 4.

  The L / S pattern thus formed was evaluated for the remaining film amount, exposure margin (EL margin), line width roughness (LWR), and line edge roughness (LER). The results are shown in Table 4.

[Residual film amount]
The amount of remaining film was determined from a cross-sectional photograph of SEM (scanning electron microscope, acceleration voltage 800 V, trade name: S-9220, manufactured by Hitachi, Ltd.).

[Exposure margin (EL margin)]
In Eop, the exposure amount when the line of the L / S pattern is formed within a range of ± 5% (47.5 nm to 52.5 nm) of the target dimension (line width 50 nm) is obtained. (Unit:%) was determined.
EL margin (%) = (| E1-E2 | / Eop) × 100
E1: Exposure amount when an L / S pattern having a line width of 47.5 nm was formed (mJ / cm ² )
E2: exposure amount (mJ / cm ² ) when an L / S pattern having a line width of 52.5 nm was formed
Note that the larger the value of the EL margin, the smaller the change amount of the pattern size accompanying the change in the exposure amount.

[Line width roughness (LWR)]
In the L / S pattern with a line width of 50 nm and a pitch of 100 nm formed by the Eop, the line width was measured by a length measurement SEM (scanning electron microscope, acceleration voltage 800 V, trade name: S-9220, manufactured by Hitachi, Ltd.). 400 points are measured in the longitudinal direction of one line, and the standard deviation (s) is multiplied by 3 (3 s) from the result, and the average value of 3 s of 5 lines is calculated as LWR. Calculated as a measure of indication.
The smaller the value of 3s, the smaller the roughness of the line width, which means that an L / S pattern having a more uniform width is formed.

[Line edge roughness (LER)]
The dimensional variation for each line of the L / S pattern was evaluated.
Specifically, the line width of 16 lines was measured with a length measuring SEM (scanning electron microscope, acceleration voltage 800 V, trade name: S-9220, manufactured by Hitachi, Ltd.), and the standard deviation calculated from the results was measured. The triple value (3s) of (s) was determined.
3s obtained in this way means that the smaller the value is, the smaller the roughness is, and an L / S pattern having a uniform width is obtained.

From the results of Table 4, Test Examples 8 and 9 using the resist material (3) and (4) containing a previously purified resin are Test Example 7 using the resist material (1) containing an untreated resin. In comparison with, the amount of remaining film was large, so that film loss was suppressed, the EL margin was good, and it was confirmed that both LWR and LER were reduced.
When the same evaluation was performed on the resist material (6), the EL margin was as good as that of Test Examples 8 to 9, but both LWR and LER were inferior.
This is presumably because, in the resist materials (3) and (4), resins such as monomers and oligomers are removed by refining the resin and a resin having a low molecular weight dispersion is blended.

Claims (8)

A first resist material that contains a resin (A1) and an organic solvent (S1) that dissolves the resin (A1) and whose solubility in an alkali developer changes upon exposure is applied to the support. Forming a first resist film, selectively exposing the first resist film, and performing alkali development to form a first resist pattern;
Containing the resin (A2) and an organic solvent (S2) that dissolves the resin (A2) and does not dissolve the resin (A1) on the support on which the first resist pattern is formed; To apply a second resist material whose solubility in an alkaline developer is changed to form a second resist film, selectively expose the second resist film, and develop an alkali to form a resist pattern A resist pattern forming method comprising:
Resin (A1) solution in which the resin (A1) is dissolved in the organic solvent (S4) in which the resin (A1) is dissolved (excluding the polymerization solution of the resin (A1)) is dissolved in the resin (A1). And the resin (A1) purified by washing with a cleaning solution containing an organic solvent (W) that dissolves the resin (A2) is added to the first resist material. Pattern forming method.   The organic solvent (S2) and the organic solvent (W) are each at least one selected from the group consisting of an alcohol-based organic solvent, a fluorine-based organic solvent, and an ether-based organic solvent having no hydroxyl group. Item 2. A resist pattern forming method according to Item 1.   The first resist material is a chemically amplified resist composition containing an acid generator that generates an acid upon exposure, and an alkaline developer by the action of an acid generated from the acid generator as the resin (A1). The resist pattern formation method of Claim 1 or 2 containing resin which the solubility with respect to changes.   The resist pattern forming method according to claim 3, wherein the resin (A1) is an acrylic resin.   The resist pattern formation method according to claim 4, wherein the resin (A1) has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.   The resist pattern forming method according to claim 5, wherein the resin (A1) further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.   The resist pattern forming method according to claim 5 or 6, wherein the resin (A1) further has a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. A first resist material that contains a resin (A1) and an organic solvent (S1) that dissolves the resin (A1) and whose solubility in an alkali developer changes upon exposure is applied to the support. Forming a first resist film, selectively exposing the first resist film, and performing alkali development to form a first resist pattern;
Containing the resin (A2) and an organic solvent (S2) that dissolves the resin (A2) and does not dissolve the resin (A1) on the support on which the first resist pattern is formed; To apply a second resist material whose solubility in an alkaline developer is changed to form a second resist film, selectively expose the second resist film, and develop an alkali to form a resist pattern And refining the resin (A1) by a resist pattern forming method comprising:
A resin (A1) solution in which the resin (A1) is dissolved in the organic solvent (S4) in which the resin (A1) is dissolved (excluding the polymerization solution of the resin (A1)) , a fluorine- based organic solvent, and a hydroxyl group . Purification of a resin characterized by washing with an organic solvent containing at least one selected from the group consisting of an ether organic solvent that does not have an alcoholic organic solvent having a boiling point of 80 to 250 ° C. under normal pressure Method.

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