KR20200088459A - Resist pattern formation method - Google Patents

Abstract

(식 (a10-1) 중, R 은 수소 원자, 알킬기 또는 할로겐화알킬기이다. Ya^x1 은 단결합 또는 2 가의 연결기이다. Wa^x1 은 (n_ax1 ＋ 1) 가의 방향족 탄화수소기이다. n_ax1 은 1 ∼ 3 의 정수이다).On the support, there is a process of forming a resist film having a thickness of 7 µm or more using a resist composition, a process of exposing a resist film, and a process of developing a resist film after exposure to form a resist pattern, wherein the resist composition is represented by the general formula (a10 Formation of a resist pattern containing a resin component having a structural unit represented by -1), a structural unit containing an acid non-aliphatic aliphatic cyclic group, and a structural unit containing an acid decomposable group whose polarity increases by the action of an acid. Way

(In formula (a10-1), R is a hydrogen atom, an alkyl group, or a halogenated alkyl group. Ya ^x1 is a single bond or a divalent linking group. Wa ^x1 is (n _ax1 + 1) valent aromatic hydrocarbon group. n _ax1 is 1 It is an integer of 3).

Description

Resist pattern formation method

The present invention relates to a method for forming a resist pattern.

This application claims priority based on Japanese Patent Application No. 2017-254871 for which it applied to Japan on December 28, 2017, and uses the content here.

In the lithography technique, for example, forming a resist film made of a resist material on a substrate, subjecting the resist film to selective exposure and developing, thereby forming a resist pattern of a predetermined shape on the resist film. This is carried out. A resist material in which the exposed portion of the resist film changes to a property that dissolves in the developer solution is positive, and a resist material in which the exposed portion of the resist film changes to a property that does not dissolve in the developer solution is called a negative type.

In recent years, in the manufacture of semiconductor devices and liquid crystal display devices, pattern refinement has been progressed by advances in lithography technology. As a method of miniaturization, short wavelength (high energy) of the exposure light source is generally performed. Specifically, conventionally, ultraviolet rays represented by g-line and i-line have been used. Currently, mass production of semiconductor devices using KrF excimer lasers or ArF excimer lasers has been carried out. In addition, studies have been conducted on EUV (extreme extreme ultraviolet), EB (electron beam), X-rays, etc. with shorter wavelengths (higher energy) than these excimer lasers.

The resist material is required to have lithography properties such as sensitivity to these exposure light sources and resolution capable of reproducing fine-dimensional patterns.

As a resist material that satisfies such a demand, conventionally, a chemically amplified resist composition containing a base component whose solubility in a developer is changed by the action of an acid and an acid generator component generating an acid by exposure is used. have.

For example, when the developer is an alkali developer (alkali developing process), as a positive type chemically amplified resist composition, a resin component (base resin) and an acid generator that increase solubility in an alkali developer by the action of an acid Ingredients containing those are generally used. When the resist film formed using such a resist composition is selectively exposed at the time of forming the resist pattern, acid is generated from the acid generator component in the exposed portion, and the polarity of the base resin increases due to the action of the acid. The exposed portion of the resist film is soluble in the alkali developer. Therefore, by developing alkali, a positive pattern in which the unexposed portion of the resist film remains as a pattern is formed.

On the other hand, when such a chemically amplified resist composition is applied to a solvent developing process using a developing solution (organic developing solution) containing an organic solvent, as the polarity of the base resin increases, solubility in the organic developing solution decreases relatively. The unexposed portion of the resist film is dissolved and removed by an organic developer, thereby forming a negative resist pattern in which the exposed portion of the resist film remains as a pattern. In this way, the solvent developing process for forming the negative resist pattern is sometimes referred to as a negative developing process.

So far, as the base resin of the chemically amplified resist composition, for example, a resin protected by a polyhydroxystyrene (PHS) having high transparency to a KrF excimer laser (248 nm) or an acid dissociable, dissolution inhibiting group. (PHS-based resin) has been used. Further, for example, for the ArF excimer laser (193 nm), a resin ((meth)acrylic resin) having a hydroxyl group in the carboxyl group of (meth)acrylic acid protected by an acid dissociable, dissolution inhibiting agent has been used (for example, , See Patent Document 1).

Examples of the acid dissociable, dissolution inhibiting group include so-called acetal groups such as chain ether groups represented by 1-ethoxyethyl groups or cyclic ether groups represented by tetrahydropyranyl groups, tertiary alkyl groups represented by tert-butyl groups, Tert-butoxycarbonyl group represented by tertiary alkoxycarbonyl group and the like are mainly used.

Further, as the acid generator component used in the chemically amplified resist composition, various types have been proposed so far, for example, onium salt-based acid generators such as iodonium salts and sulfonium salts, and oxime sulfonate series Acid generators, diazomethane acid generators, nitrobenzylsulfonate acid generators, iminosulfonate acid generators, disulfone acid generators, and the like are known.

Among these, onium salt-based acid generators are widely used, and those having onium ions such as triphenylsulfonium are mainly used in the cation moiety. As the anion portion of the onium salt-based acid generator, an alkylsulfonic acid ion or a fluorinated alkylsulfonic acid ion in which part or all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms is generally used.

By the way, currently, with high integration of LSI and high speed of communication, an increase in memory capacity is required, and further miniaturization of patterns is rapidly progressing. However, in lithography using electron beams or EUVs, the goal is to form a fine pattern of several tens of nm, but there are still many problems such as low productivity, and there is a limit to the technology by micromachining.

On the other hand, in addition to miniaturization, the development of a three-dimensional structure device that promotes a large-capacity memory by stacking cells is stacked.

Japanese Patent Application Publication No. 2003-241385

In the production of the three-dimensional structure device, a step of forming a thick film resist film having a higher film thickness, for example, a film thickness of 7 µm or more, on the surface of the workpiece, and forming a resist pattern to perform etching, etc. Have When a chemically amplified resist composition is used here, the thicker the film thickness of the resist, the more difficult it is to maintain sensitivity during exposure. When an attempt is made to form a thick film resist film using a conventional chemically amplified resist composition, there is a problem that a large amount of exposure is required and sensitivity is lowered. In addition, there is also a problem that resolution against development is lowered, and it is difficult to obtain a desired resist pattern shape.

The present invention has been made in view of the above circumstances, and provides a method for forming a resist pattern that exhibits high sensitivity and can form a pattern of good shape even when a thick film resist film having a film thickness of 7 µm or more is formed. The task is to do it.

In order to solve the said subject, this invention employs the following structures.

That is, in the method for forming a resist pattern according to one aspect of the present invention, a step (i) of forming a resist film having a film thickness of 7 µm or more using a resist composition on a support, and a step of exposing the resist film (ii) ) And the step (iii) of forming a resist pattern by developing the resist film after exposure, wherein the resist composition generates acid by exposure, and the solubility in the developer changes by the action of the acid. The structural unit (a10) represented by the following general formula (a10-1), the structural unit (a4) containing an acid non-aliphatic aliphatic cyclic group, and an acid-decomposable group whose polarity increases by the action of an acid are included. It is characterized by containing the resin component (A1) which has the structural unit (a1) mentioned above.

[Formula 1]

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Ya ^x1 is a single bond or a divalent linking group. Wa ^x1 is a (n _ax1 + 1) valent aromatic hydrocarbon group. n _ax1 is an integer of 1-3.]

According to the present invention, even when a thick film resist film having a film thickness of 7 µm or more is formed, it is possible to provide a resist pattern forming method that exhibits high sensitivity and can form a pattern with a good shape.

In the present specification and the claims, "aliphatic" is defined as a concept relative to aromatic, meaning a group, a compound, etc. that does not have aromaticity.

The "alkyl group" is intended to contain a monovalent saturated hydrocarbon group of a straight chain, branched chain, and cyclic form, unless otherwise specified. The alkyl group in the alkoxy group is also the same.

The "alkylene group" is intended to contain a divalent saturated hydrocarbon group of a straight chain, branched chain, and cyclic type, unless otherwise specified.

The "halogenated alkyl group" is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with halogen atoms, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The "fluorinated alkyl group" or "fluorinated alkylene group" refers to a group in which a part or all of the hydrogen atoms of the alkyl group or alkylene group are substituted with fluorine atoms.

The "constituent unit" means a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).

When describing "you may have a substituent", both the case where a hydrogen atom (-H) is substituted with a monovalent group, and the case where a methylene group (-CH ₂ -) is substituted with a divalent group are included.

"Exposure" is a concept that includes the entire irradiation of radiation.

The "constituent unit derived from an acrylic acid ester" means a structural unit constituted by cleavage of an ethylenic double bond of an acrylic acid ester.

"Acrylic acid ester" is a compound in which the hydrogen atom at the terminal of the carboxyl group of acrylic acid (CH ₂ =CH-COOH) is substituted with an organic group.

In the acrylic acid ester, a hydrogen atom bonded to a carbon atom at the α position may be substituted with a substituent. The substituent (R ^α0 ) for substituting a hydrogen atom bonded to a carbon atom at the α position is an atom or group other than a hydrogen atom, and examples thereof include an alkyl group having 1 to 5 carbon atoms, an alkyl halide group having 1 to 5 carbon atoms, and the like. have. In addition, it also includes an itaconic acid diester in which the substituent (R ^α0 ) is substituted with a substituent containing an ester bond, or α hydroxyacrylic ester in which the substituent (R ^α0 ) is substituted with a hydroxyalkyl group or a group modified with the hydroxyl group thereof. do. Further, the carbon atom at the α position of the acrylic acid ester is a carbon atom to which the carbonyl group of acrylic acid is bonded unless otherwise specified.

Hereinafter, the acrylic acid ester in which the hydrogen atom bonded to the carbon atom at the α position is substituted with a substituent may be referred to as an α-substituted acrylic acid ester. Moreover, an acrylic acid ester and an alpha substituted acrylic acid ester are collectively called "(alpha substituted) acrylic acid ester." Moreover, the acrylic acid in which the hydrogen atom bonded to the carbon atom at the α position is substituted with a substituent may be referred to as α-substituted acrylic acid. In addition, acrylic acid and α-substituted acrylic acid may be collectively referred to as “(α-substituted) acrylic acid”.

"Structural unit derived from acrylamide" means a structural unit formed by cleaving the ethylenic double bond of acrylamide.

In acrylamide, the hydrogen atom bonded to the carbon atom at the α position may be substituted with a substituent, or one or both hydrogen atoms of the amino group of acrylamide may be substituted with a substituent. In addition, the carbon atom in the α position of acrylamide is a carbon atom to which the carbonyl group of acrylamide is bonded unless otherwise specified.

As a substituent which substitutes the hydrogen atom couple|bonded with the carbon atom of the alpha position of acrylamide, the thing same as what was given as the substituent of the alpha position (substituent (R ^{alpha 0} )) in the said alpha substituted acrylic acid ester.

The "constituent unit derived from hydroxystyrene" means a structural unit formed by cleavage of the ethylenic double bond of hydroxystyrene. The "constituent unit derived from a hydroxystyrene derivative" means a structural unit formed by cleavage of an ethylenic double bond of a hydroxystyrene derivative.

The term "hydroxystyrene derivative" refers to a concept in which the hydrogen atom at the α position of hydroxystyrene is substituted with another substituent such as an alkyl group or a halogenated alkyl group, and derivatives thereof. As their derivatives, the hydrogen atom in the hydroxyl group of the hydroxystyrene which may be substituted with a substituent at the hydrogen atom at the α position is an organic group; The thing in which the substituent other than a hydroxyl group couple|bonded with the benzene ring of the hydroxystyrene which the hydrogen atom of the alpha position may be substituted with the substituent is mentioned. Note that the α position (the carbon atom at the α position) refers to a carbon atom to which the benzene ring is attached, unless otherwise specified.

As a substituent which substitutes the hydrogen atom of the alpha position of hydroxystyrene, the thing similar to what was mentioned as the substituent of the alpha position in the said alpha substituted acrylic acid ester is mentioned.

"Constituent unit derived from vinylbenzoic acid or vinylbenzoic acid derivative" means a structural unit formed by cleavage of an ethylenic double bond of vinylbenzoic acid or vinylbenzoic acid derivative.

The "vinyl benzoic acid derivative" is a concept including a hydrogen atom at the α position of vinyl benzoic acid substituted with another substituent such as an alkyl group or a halogenated alkyl group, and derivatives thereof. As their derivatives, the hydrogen atom at the carboxyl group of vinylbenzoic acid in which the hydrogen atom at the α position may be substituted with a substituent is an organic group; The thing which the substituent other than a hydroxyl group and a carboxy group couple|bonded with the benzene ring of the vinylbenzoic acid in which the hydrogen atom of the alpha position may be substituted with the substituent etc. is mentioned. Note that the α position (the carbon atom at the α position) refers to a carbon atom to which the benzene ring is attached, unless otherwise specified.

The alkyl group as the substituent at the α position is preferably a linear or branched chain alkyl group, specifically, an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, iso And butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group) and the like.

Moreover, the halogenated alkyl group as a substituent of the α position specifically, a group in which a part or all of the hydrogen atoms of the “alkyl group as a substituent of the α position” is substituted with a halogen atom. 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.

Moreover, the hydroxyalkyl group as a substituent of the alpha position specifically, group which substituted some or all of the hydrogen atom of the said "alkyl group as a substituent of the alpha position" with a hydroxyl group is mentioned. 1-5 are preferable and, as for the number of hydroxyl groups in the hydroxyalkyl group, 1 is the most preferable.

In the present specification and claims, depending on the structure represented by the formula, there may be sub-carbon, and there may be an enantiomer or a diastereomer, but in that case, in one formula They represent isomers. These isomers may be used alone or as a mixture.

(How to form a resist pattern)

In the method for forming a resist pattern of the present embodiment, a step (i) of forming a resist film having a thickness of 7 µm or more using a resist composition on a support, (ii) exposing the resist film, and developing the resist film after the exposure are developed. And a step (iii) of forming a resist pattern. In the method for forming a resist pattern of this aspect, in step (i), a specific resist composition is selected.

The method for forming a resist pattern according to this aspect can be carried out, for example, as follows.

Process (i):

First, on the support, a specific resist composition to be described later is coated with a spinner or the like, and the bake (post-applied bake (PAB)) treatment is, for example, 80 to 150°C, preferably 100 to 150°C (more preferred) It is carried out for 40 to 120 seconds, preferably 60 to 120 seconds (more preferably 80 to 100 seconds) under a temperature condition of more than 100°C and more than 150°C) to form a resist film having a thickness of 7 µm or more.

Process (ii):

Next, the resist film is subjected to selective exposure by exposure or the like through a mask (mask pattern) on which a predetermined pattern is formed, for example, using an exposure apparatus or the like, followed by baking (post exposure bake (PEB)) treatment For example, it is carried out for 40 to 120 seconds, preferably 60 to 100 seconds, at a temperature condition of 80 to 150°C, preferably 90 to 130°C.

Process (iii):

Next, the resist film after the exposure is developed. The developing treatment is performed using an alkali developing solution in the case of an alkali developing process, and a developing solution (organic developing solution) containing an organic solvent in the case of a solvent developing process.

After the developing treatment, rinsing treatment is preferably performed. For the rinse treatment, in the case of the alkali developing process, water rinsing using pure water is preferable, and in the case of the solvent developing process, it is preferable to use a rinse liquid containing an organic solvent.

In the case of the solvent developing process, after the developing treatment or the rinsing treatment, a treatment in which the developing solution or the rinsing liquid attached to the pattern is removed with a supercritical fluid may be performed.

After developing treatment or rinsing treatment, drying is performed. In addition, in some cases, a baking treatment (post baking) may be performed after the developing treatment.

In this way, a resist pattern can be formed.

It does not specifically limit as a support body, A conventionally well-known thing can be used, For example, the board|substrate for electronic components, the thing in which a predetermined wiring pattern was formed in this, etc. are mentioned. More specifically, a silicon wafer, a metal substrate such as copper, chromium, iron, aluminum, or a glass substrate can be cited. As the material of the wiring pattern, copper, aluminum, nickel, gold, or the like can be used, for example.

Further, as the support, an inorganic and/or organic film may be formed on the substrate as described above. An inorganic antireflection film (inorganic BARC) is mentioned as an inorganic film. Examples of the organic film include organic antireflection films (organic BARC) and organic films such as lower layer organic films in the multilayer resist method.

Here, with the multilayer resist method, at least one layer of an organic film (lower layer organic film) and at least one layer of a resist film (upper layer resist film) are formed on a substrate, and a resist pattern formed on the upper layer resist film is used as a mask. This is a method of patterning the lower organic film, and it is said that a pattern with a high aspect ratio can be formed. That is, according to the multilayer resist method, since the required thickness can be ensured by the lower organic film, the resist film can be thinned, and fine pattern formation with a high aspect ratio can be achieved.

In the multilayer resist method, basically, a method of forming a two-layer structure of an upper resist film and a lower organic film (two-layer resist method) and one or more intermediate layers (metal thin film, etc.) are formed between the upper resist film and the lower organic film. It is divided into a method having a multi-layer structure of three or more layers (three-layer resist method).

The resist pattern forming method of this aspect is a useful method when forming a resist film having a high film thickness, and the film thickness of the resist film formed in the step (i) is 7 µm or more.

The film thickness of the resist film formed in the step (i) is more preferably 8 µm or more, particularly preferably 10 µm or more, and the upper limit of the film thickness is substantially 30 µm or less.

The wavelength used for exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. It can be carried out using radiation.

The method for forming a resist pattern according to this aspect is a particularly preferable method in the step (ii), when the KrF excimer laser light is irradiated to the resist film.

The exposure method of the resist film may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or liquid immersion lithography.

The immersion exposure is an exposure method in which the resist film and the lens at the lowest position of the exposure apparatus are previously filled with a solvent (immersion medium) having a refractive index greater than the refractive index of air, and exposure (immersion exposure) is performed in that state.

As the immersion medium, a solvent having a refractive index larger than that of air and smaller than that of the resist film to be exposed 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, fluorine-based inert liquids, silicon-based solvents, and hydrocarbon-based solvents.

Specific examples of the fluorine-based inert liquid include liquids containing fluorine-based compounds 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. The boiling point is preferably 70 to 180°C, and more preferably 80 to 160°C. If the fluorine-based inert liquid has a boiling point in the above range, it is preferable from the point that the medium used for immersion can be removed by an easy method after completion of exposure.

As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are replaced with fluorine atoms is particularly preferable. As a perfluoroalkyl compound, a perfluoroalkyl ether compound and a perfluoroalkylamine compound are specifically, mentioned.

Further, specifically, as the perfluoroalkyl ether compound, perfluoro (2-butyl-tetrahydrofuran) (boiling point 102 deg. C) may be mentioned. As the perfluoroalkylamine compound, perfluoro Rotributylamine (boiling point 174°C).

As the immersion medium, water is preferably used from the viewpoints of cost, safety, environmental problems, and versatility.

As an alkali developing solution used for image development process in an alkali developing process, 0.1-10 mass% tetramethylammonium hydroxide (TMAH) aqueous solution is mentioned, for example.

As the organic solvent contained in the organic developing solution used for the developing treatment in the solvent developing process, any component (A) (the component (A) before exposure) may be dissolved, and it can be appropriately selected from known organic solvents. Specifically, polar solvents, such as a ketone solvent, an ester solvent, an alcohol solvent, a nitrile solvent, an amide solvent, and an ether solvent, a hydrocarbon solvent, etc. are mentioned.

The ketone-based solvent is an organic solvent containing C-C(=O)-C in the structure. The ester solvent is an organic solvent containing C-C(=O)-O-C in the structure. The alcohol-based solvent is an organic solvent containing an alcoholic hydroxyl group in the structure. "Alcoholic hydroxyl group" means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. The nitrile-based solvent is an organic solvent containing a nitrile group in the structure. The amide-based solvent is an organic solvent containing an amide group in the structure. The ether-based solvent is an organic solvent containing C-O-C in the structure.

Among the organic solvents, there are also organic solvents containing plural kinds of functional groups that characterize the respective solvents in the structure, but in that case, it is also applicable to any solvent species containing functional groups of the organic solvents. For example, diethylene glycol monomethyl ether shall be applicable to either the alcohol-based solvent or the ether-based solvent in the above classification.

The hydrocarbon-based solvent is a hydrocarbon solvent composed of hydrocarbons which may be halogenated and does not have a substituent other than a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.

As the organic solvent contained in the organic developer, a polar solvent is preferred, and a ketone solvent, an ester solvent, a nitrile solvent, etc. are preferable.

As a ketone solvent, for example, 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl Ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methylethylketone, methylisobutylketone, acetylacetone, acetonyl acetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methylnaphthyl ketone, Isophorone, propylene carbonate, γ-butyrolactone, methyl amyl ketone (2-heptanone), and the like. Among these, methyl amyl ketone (2-heptanone) is preferable as the ketone solvent.

Examples of the ester solvent include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxy acetate, ethyl ethoxy acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol Monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate , Diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl Acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate , 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4- Methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, Propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, methyl 2-hydroxypropionate, methyl-3-methoxypropionate , Ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, and the like. Among these, butyl acetate is preferable as the ester solvent.

Examples of the nitrile solvent include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

Known additives can be added to the organic developer, if necessary. Examples of the additives include surfactants. Although it does not specifically limit as surfactant, For example, ionic or nonionic fluorine type and/or silicone type surfactant, etc. can be used. As the surfactant, a nonionic surfactant is preferable, and a nonionic fluorine-based surfactant or nonionic silicone-based surfactant is more preferable.

When a surfactant is blended, the blending amount is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass relative to the total amount of the organic developer.

The developing treatment can be carried out by a known developing method, for example, a method of immersing the support in a developer for a certain time (dip method), a method of stopping the developer by a surface tension on the surface of the support for a fixed time (puddle) Method), a method of spraying a developer on the surface of a support (spray method), a method of continuously drawing a developer while scanning a nozzle for developing a developer at a constant speed on a support rotating at a constant speed (dynamic dispensing method), and the like. .

As the organic solvent contained in the rinse liquid used for the rinse treatment after the developing treatment in the solvent developing process, for example, among the organic solvents used as the organic solvent used for the organic developer, a resist pattern that is difficult to dissolve is suitably selected and used. Can. Usually, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents and ether solvents is used. Among them, at least one selected from hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, alcohol-based solvents and amide-based solvents is preferable, and at least one selected from alcohol-based solvents and ester-based solvents is more preferred, and alcohol-based solvents are preferred. Solvents are particularly preferred.

The alcohol-based solvent used for the rinse liquid is preferably a monohydric alcohol having 6 to 8 carbon atoms, and the monohydric alcohol may be any of linear, branched or cyclic. Specifically, 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4 -Octanol, benzyl alcohol, and the like. Among these, 1-hexanol, 2-heptanol, and 2-hexanol are preferable, and 1-hexanol and 2-hexanol are more preferable.

Any one of these organic solvents may be used alone, or two or more of them may be used in combination. Moreover, you may use it, mixing with the organic solvent other than the above and water. However, considering the development characteristics, the blending amount of water in the rinse liquid is preferably 30% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, 3 Particularly preferred is mass% or less.

Known additives can be added to the rinse liquid as necessary. Examples of the additives include surfactants. As the surfactant, the same ones described above can be mentioned, and nonionic surfactants are preferred, and nonionic fluorine-based surfactants or nonionic silicone-based surfactants are more preferred.

When a surfactant is blended, the blending amount is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass relative to the total amount of the rinse liquid.

The rinse treatment (washing treatment) using a rinse liquid can be performed by a known rinse method. As a method of the rinsing treatment, for example, a method of continuously drawing a rinse liquid on a support rotating at a constant speed (rotation coating method), a method of immersing the support in a rinse liquid for a certain time (dip method), on the surface of the support The method of spraying a rinse liquid (spray method), etc. are mentioned.

<resist composition>

In the method for forming a resist pattern of the present embodiment described above, in step (i), a specific resist composition is used.

In such a specific resist composition, an acid is generated by exposure, and solubility in a developer is changed by the action of an acid. As this resist composition, the embodiment containing the base component (A) (it is also hereafter referred to as "(A) component") whose solubility in a developer is changed by the action of an acid is exemplified.

The resist composition of this embodiment is suitable for forming a resist pattern that exposes KrF excimer laser light.

Moreover, the resist composition of this embodiment is useful as a resist agent for forming a resist film having a high film thickness on a support, and is suitable for forming a resist film having a film thickness of 7 µm or more.

When a resist film is formed using the resist composition of the present embodiment, and the resist film is selectively exposed, acid is generated in the exposed portion of the resist film, and the action of the acid (A) solubility of the component in the developer solution On the other hand, since the solubility of the component (A) in the unexposed portion of the resist film does not change in the unexposed portion of the resist film, a difference in solubility to the developer occurs between the exposed portion of the resist film and the unexposed portion. Therefore, when the resist film is developed, when the resist composition is positive, the resist film exposed portion is dissolved and removed to form a positive resist pattern, and when the resist composition is negative, the resist film unexposed portion is dissolved and removed to be negative. A resist pattern of the mold is formed.

In the present specification, a resist composition in which the exposed portion of the resist film is dissolved and removed to form a positive resist pattern is referred to as a positive resist composition, and a resist composition in which the unexposed portion of the resist film is dissolved and removed to form a negative resist pattern is negative. It is called a mold resist composition.

The resist composition of the present embodiment may be either a positive resist composition or a negative resist composition.

Further, the resist composition of the present embodiment may be for an alkali developing process using an alkali developer for developing processing at the time of forming a resist pattern, and a solvent developing process using a developing solution (organic developer) containing an organic solvent for the developing process. It may be a dragon.

In short, the resist composition of the present embodiment is a "positive-type resist composition for an alkali developing process" that forms a positive resist pattern in an alkali developing process, and a "solvent developing process" that forms a negative resist pattern in a solvent developing process. Dragon Negative Resist Composition”.

The resist composition of the present embodiment has an acid generating ability to generate an acid by exposure, and the component (A) may generate an acid by exposure, and an additive component formulated separately from the component (A) is used for exposure. You may generate an acid by.

Specifically, the resist composition of the embodiment may include (1) an acid generator component (B) (hereinafter referred to as "(B) component") that generates an acid by exposure; (2) The component (A) may be a component that generates an acid by exposure; (3) The component (A) is a component that generates acid upon exposure, and may further contain a component (B).

That is, in the case of the above (2) or (3), the component (A) becomes "a base component that generates an acid by exposure and the solubility in a developer is changed by the action of the acid." (A) When a component is a base component which generates an acid by exposure and the solubility in a developer solution changes by the action of an acid, the component (A1) described later generates an acid by exposure, and further, It is preferable that it is a high molecular compound whose solubility in a developer is changed by the action of an acid. As such a polymer compound, a copolymer having a structural unit that generates an acid by exposure can be used.

As a structural unit which generates an acid by exposure, a well-known thing is mentioned, for example.

It is particularly preferable that the resist composition of the present embodiment is the case of (1) above.

≪(A) component≫

The component (A) is a base component whose solubility in a developing solution changes by the action of an acid.

In the present embodiment, the "base component" 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 it is easy to form a nano-level resist pattern.

Organic compounds used as the base component are largely divided 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, in the case of a "low molecular compound", a non-polymer having a molecular weight of 500 or more and less than 4000 is shown.

As the polymer, one having a molecular weight of 1000 or more is usually used. Hereinafter, in the case of "resin", "polymer compound" or "polymer", a polymer having a molecular weight of 1000 or more is represented.

As the molecular weight of the polymer, it is assumed that a weight average molecular weight in terms of polystyrene by GPC (gel permeation chromatography) is used.

The component (A) in the resist composition of the present embodiment includes a resin component (A1) (hereinafter also referred to as “(A1) component”) in which solubility in a developer is changed by the action of an acid.

As the component (A), at least the component (A1) is used, and other polymer compounds and/or low molecular compounds may be used in combination with the component (A1).

(A1) component in this embodiment, the structural unit (a10) represented by general formula (a10-1) mentioned later, the structural unit (a4) containing an acid non-aliphatic aliphatic cyclic group, and the action of an acid It has a structural unit (a1) containing an acid-decomposable group whose polarity increases. In addition to the structural unit (a10), the structural unit (a4), and the structural unit (a1), the component (A1) may have other structural units as necessary.

In the resist composition of the present embodiment, since the structural unit (a1) contains an acid dissociable group, the polarity of the resin component changes before and after exposure by using the component (A1), and not only the alkali developing process, but also solvent development. Even in the process, good development contrast can be obtained between the exposed portion of the resist film and the unexposed portion.

When the alkali developing process is applied, the component (A1) is poorly soluble in the alkali developer before exposure. For example, when acid is generated from the component (B) by exposure, the polarity increases due to the action of the acid. Thus, the solubility in the alkali developer increases. Therefore, in forming a resist pattern, when the resist composition is selectively exposed to a resist film obtained by applying the resist composition on a support, the resist film exposure section changes from poorly soluble to soluble in an alkali developer, while the resist film is minus Since the light portion is hardly soluble in alkali and does not change, a positive resist pattern is formed by alkali development.

On the other hand, when the solvent developing process is applied, the component (A1) has high solubility in an organic developer before exposure, for example, when acid is generated from the component (B) by exposure, polarity is caused by the action of the acid. This increases, solubility in organic developer decreases. Therefore, in forming a resist pattern, when the resist composition obtained by coating the resist composition on a support is selectively exposed, the resist film exposed portion changes from soluble to poorly soluble in an organic developer, while the resist film is minus Since the light portion does not change while being soluble, a negative resist pattern is formed by developing with an organic developer.

About the structural unit (a10):

The structural unit (a10) is a structural unit represented by the following general formula (a10-1).

[Formula 2]

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Ya ^x1 is a single bond or a divalent linking group. Wa ^x1 is a (n _ax1 + 1) valent aromatic hydrocarbon group. n _ax1 is an integer of 1-3.]

In said formula (a10-1), R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group.

The alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched chain alkyl group having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl Group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. The halogenated alkyl group having 1 to 5 carbon atoms in R is a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. 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.

As R, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms is preferable, and from the ease of industrial availability, a hydrogen atom or a methyl group is most preferred.

In the formula (a10-1), Ya ^x1 is a single bond or a divalent linking group.

Examples of the divalent linking group in Ya ^x1 include, for example, a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

Divalent hydrocarbon group which may have a substituent:

When Ya ^x1 is a divalent hydrocarbon group which may have a substituent, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

・The aliphatic hydrocarbon group in Ya ^x1

The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is preferably saturated.

Examples of the aliphatic hydrocarbon group include a straight-chain or branched-chain aliphatic hydrocarbon group, or an aliphatic hydrocarbon group containing a ring in the structure.

A straight-chain or branched-chain aliphatic hydrocarbon group

The straight-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms.

As a linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specifically, a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) ₂ -], a trimethylene group [-( And CH ₂ ) ₃ -], tetramethylene group [-(CH ₂ ) ₄ -], and pentamethylene group [-(CH ₂ ) ₅ -].

The branched-chain aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms.

As the branched-chain aliphatic hydrocarbon group, a branched-chain alkylene group is preferable, and specifically, -CH(CH ₃ )-, -CH(CH ₂ CH ₃ )-, -C(CH ₃ ) ₂ -,- Alkyl methylene groups such as C(CH ₃ )(CH ₂ CH ₃ )-, -C(CH ₃ )(CH ₂ CH ₂ CH ₃ )-, -C(CH ₂ CH ₃ ) _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 -, -C(CH ₂ CH ₃ ) alkyl ethylene groups such as ₂ -CH ₂ -; Alkyltrimethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ -; And an alkylalkylene group such as an alkyltetramethylene group such as -CH(CH ₃ )CH ₂ CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ CH ₂ -, and the like. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

The said linear or branched-chain aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a C1-C5 fluorinated alkyl group substituted with a fluorine atom, a carbonyl group, and the like.

An aliphatic hydrocarbon group containing a ring in the structure

As the aliphatic hydrocarbon group containing a ring in the structure, a cyclic aliphatic hydrocarbon group (a group in which two hydrogen atoms are removed from an aliphatic hydrocarbon ring) which may include a substituent containing a hetero atom in the ring structure, the cyclic aliphatic The group which the hydrocarbon group couple|bonded to the terminal of the linear or branched-chain aliphatic hydrocarbon group, the group etc. which the said cyclic aliphatic hydrocarbon group interposed in the middle of a linear or branched-chain aliphatic hydrocarbon group etc. are mentioned. The thing similar to the above is mentioned as said linear or branched-chain 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 alicyclic hydrocarbon group, a group in which two hydrogen atoms are removed from monocycloalkane is preferable. As the monocycloalkane, those having 3 to 6 carbon atoms are preferable, and specific examples thereof include cyclopentane and cyclohexane. As the polycyclic alicyclic hydrocarbon group, a group in which two hydrogen atoms are removed from polycycloalkane is preferable, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, And isobornane, tricyclodecane, and tetracyclododecane.

The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and a carbonyl group.

The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, ethyl group, propyl group, n-butyl group or tert-butyl group.

The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, Time, an ethoxy group is most preferable.

Examples of the halogen atom as the substituent 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 include a group in which part or all of the hydrogen atoms of the alkyl group are substituted with the halogen atom.

The cyclic aliphatic hydrocarbon group may be partially substituted with a substituent containing a hetero atom in a part of the carbon atoms constituting the ring structure. As a substituent containing the hetero atom, -O-, -C(=O)-O-, -S-, -S(=O) ₂ -, -S(=O) ₂ -O- are preferable. .

Aromatic hydrocarbon group in Ya ^x1

The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring.

The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4 n + 2 π electrons, and may be monocyclic or polycyclic. It is preferable that carbon number of an aromatic ring is 5-30, 5-20 are more preferable, 6-15 are still more preferable, and 6-12 are especially preferable. However, it is assumed that the carbon number in the substituent is not included in the carbon number. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene and phenanthrene; And aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. As a hetero atom in an aromatic heterocycle, an oxygen atom, a sulfur atom, a nitrogen atom, etc. are mentioned.

A pyridine ring, a thiophene ring, etc. are mentioned specifically, as an aromatic heterocycle.

Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms are removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene group or heteroarylene group); A group in which two hydrogen atoms are removed from an aromatic compound (eg, biphenyl, fluorene, etc.) containing two or more aromatic rings; A group in which one of the hydrogen atoms of a group (aryl group or heteroaryl group) in which one hydrogen atom is removed from the aromatic hydrocarbon ring or aromatic hetero ring is substituted with an alkylene group (for example, a benzyl group, a phenethyl group, 1-naph And a group in which one hydrogen atom is further removed from an aryl group in an arylalkyl group such as a tilmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, and a 2-naphthylethyl group). The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

The aromatic hydrocarbon group may have a hydrogen atom of the aromatic hydrocarbon group substituted with a substituent. For example, the hydrogen atom bonded to the aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group.

The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, ethyl group, propyl group, n-butyl group or tert-butyl group.

As an alkoxy group, a halogen atom, and a halogenated alkyl group as said substituent, what was illustrated as a substituent which substitutes the hydrogen atom which the said cyclic aliphatic hydrocarbon group has is mentioned.

Divalent linking group containing a hetero atom:

When Ya ^x1 is a divalent linking group containing a hetero atom, preferred as the linking group are -O-, -C(=O)-O-, -C(=O)-, -OC(=O)-O -, -C(=O)-NH-, -NH-, -NH-C(=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-, general formula -Y ²¹ -OY ²² -, -Y ²¹ -O-, -Y ²¹ -C(=O)-O-, -C( =O)-OY ²¹ -, -[Y ²¹ -C(=O)-O] _m" -Y ²² -, -Y ²¹ -OC(=O)-Y ²² -or -Y ²¹ -S(=O ) Group represented by ₂ -OY ^22- [wherein, Y ²¹ and Y ²² are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m" is an integer from 0 to 3.] And the like.

The divalent linking group containing the hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, -NH-C(=NH)- In that case, the H may be substituted with a substituent such as an alkyl group or an acyl group. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.

General formula -Y ²¹ -OY ²² -, -Y ²¹ -O-, -Y ²¹ -C(=O)-O-, -C(=O)-OY ²¹ -, -[Y ²¹ -C(=O )-O] _m" -Y ²² -, -Y ²¹ -OC(=O)-Y ²² -or -Y ²¹ -S(=O) ₂ -OY ²² -among, Y ²¹ and Y ²² are each independently It is a divalent hydrocarbon group which may have a substituent, and the bivalent hydrocarbon group is the same as the one described in the description as the divalent linking group (a divalent hydrocarbon group which may have a substituent).

As Y ²¹ , a straight-chain aliphatic hydrocarbon group is preferable, a straight-chain alkylene group is more preferable, and a C1-C5 straight-chain alkylene group is more preferable, and a methylene group or ethylene group is particularly preferable.

As Y ²² , a straight-chain or branched-chain aliphatic hydrocarbon group is preferable, and a methylene group, an ethylene group, or an alkylmethylene group is more preferable. 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.

In the group represented by the formula -[Y ²¹ -C(=O)-O] _m" -Y ²² -, m" is an integer from 0 to 3, preferably an integer from 0 to 2, and 0 or 1 is more Preferred, 1 is particularly preferred. That is, as the group represented by the formula -[Y ²¹ -C(=O)-O] _m" -Y ²² -, the group represented by the formula -Y ²¹ -C(=O)-OY ²² -is particularly preferred. , The group represented by the formula -(CH ₂ ) _a'- C(=O)-O-(CH ₂ ) _b' -is preferable, wherein a'is an integer of 1 to 10, and is 1 to 8 An integer is preferred, an integer from 1 to 5 is more preferred, 1 or 2 is more preferred, and 1 is most preferred, b'is an integer from 1 to 10, an integer from 1 to 8 is preferred, 1 The integer of -5 is more preferable, 1 or 2 is still more preferable, and 1 is the most preferable.

As Ya ^x1 , a single bond, an ester bond [-C(=O)-O-], an ether bond (-O-), -C(=O)-NH-, a straight chain or branched chain alkylene group, Or it is preferable that it is a combination of these, and a single bond is especially more preferable among them.

In the formula (a10-1), Wa ^x1 is a (n _ax1 + 1) valent aromatic hydrocarbon group.

The aromatic hydrocarbon group for Wa ^x1 includes a group in which (n _ax1 + 1) hydrogen atoms are removed from the aromatic ring. The aromatic ring here is not particularly limited as long as it is a cyclic conjugate system having 4n + 2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, further preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene and phenanthrene; And aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. As a hetero atom in an aromatic heterocycle, an oxygen atom, a sulfur atom, a nitrogen atom, etc. are mentioned. A pyridine ring, a thiophene ring, etc. are mentioned specifically, as an aromatic heterocycle.

In the formula (a10-1), n _ax1 is an integer of 1 to 3, 1 or 2 is preferable, and 1 is more preferable.

Below, the specific example of the structural unit represented by said general formula (a10-1) is shown.

In the following formulae, R ^α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

The structural unit (a10) of the component (A1) may be one type or two or more types.

Among the above, the structural unit (a10) is preferably a structural unit containing a hydroxystyrene skeleton, and particularly preferably a structural unit represented by the following general formula (a10-1-0).

[Formula 7]

[In the formula, R ^st represents a hydrogen atom or a methyl group. m ₀₁ represents the integer of 1-3.]

In the component (A1), the proportion of the structural unit (a10) is preferably 40 to 80 mol%, and 45 to 75 mol%, based on the total (100 mol%) of all the constituent units constituting the component (A1). Is more preferable, and 50 to 70 mol% is particularly preferable.

By setting the proportion of the structural unit (a10) to be more than the lower limit of the preferred range, the sensitivity, development characteristics, and the effect of suppressing the occurrence of defects are further improved. On the other hand, by setting the ratio to the upper limit of the preferred range or less, dimensional uniformity, etc. The lithography characteristics of are further improved.

・About the structural unit (a4):

The structural unit (a4) is a structural unit containing an acid non-aliphatic aliphatic cyclic group.

When the component (A1) has a structural unit (a4), the light transmittance of the resist film is increased as compared to the case where the component has a structural unit containing an aromatic cyclic group. Moreover, the dry etching resistance of the resist pattern to be formed improves, and the hydrophobicity of the component (A) increases. The improvement in hydrophobicity contributes to improvement in resolution, resist pattern shape, and the like, especially in the case of resist pattern formation by a solvent development process.

The "acid non-cyclic cyclic group" in the structural unit (a4) acts when an acid is generated in the resist composition (e.g., when an acid is generated from the component (B) described later) by exposure. It is a cyclic group remaining in the structural unit without dissociation even if it is dissociated.

The acid non-aliphatic aliphatic cyclic group in the structural unit (a4) may be a monocyclic group or a polycyclic group, and is preferably a monocyclic group.

As the monocyclic group here, a group in which one or more hydrogen atoms are removed from monocycloalkane is preferable. As the monocycloalkane, those having 3 to 8 carbon atoms are more preferable, those having 5 to 8 carbon atoms are more preferable, and specific examples thereof include cyclopentane, cyclohexane, and cyclooctane. As the polycyclic group here, a group in which one or more hydrogen atoms are removed from polycycloalkane is preferable, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, and iso And bornan, tricyclodecane, and tetracyclododecane.

The monocyclic group and the polycyclic group may each have, for example, a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.

Examples of the structural unit (a4) include a structural unit derived from an acrylic acid ester in which a hydrogen atom bonded to a carbon atom at the α position may be substituted with a substituent, a structural unit derived from acrylamide, and the like, bonded to a carbon atom at the α position The structural unit derived from the acrylic acid ester in which the hydrogen atom may be substituted with a substituent is preferable.

Below, the specific example of a structural unit (a4) is shown.

In the following formulae, R ^α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[Formula 8]

(A1) The structural unit (a4) which a component has may be 1 type, or 2 or more types may be sufficient as it.

Among the above, the structural unit (a4) is preferably an acid non-reactive and structural unit containing a monocyclic aliphatic cyclic group, and is composed of structural units represented by any of the formulas (a4-7) to (a4-10). Preference is given to at least one species selected from the group.

In the component (A1), the proportion of the structural unit (a4) is preferably 1 to 50 mol%, and 2 to 50 mol, with respect to the total (100 mol%) of the total constituent units constituting the component (A1). % Is more preferable, and 5 to 45 mol% is more preferable.

By making the ratio of the structural unit (a4) more than the lower limit of the above-described preferred range, the light transmittance of the resist film is further increased, and high sensitivity and resolution can be improved. On the other hand, when it is below the upper limit of the preferable range, it becomes easy to balance with other structural units.

・About the structural unit (a1):

The structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity increases by the action of an acid.

The "acid-decomposable group" is a group having an acid-decomposable property capable of cleaving at least a part of the structure of the acid-decomposable group under the action of an acid.

Examples of the acid-decomposable group in which the polarity increases by the action of an acid include groups that decompose under the action of an acid to produce a polar group.

As a polar group, a carboxy group, a hydroxyl group, an amino group, a sulfo group (-SO ₃ H) etc. are mentioned, for example. Among these, a polar group containing -OH in the structure (hereinafter sometimes referred to as "OH-containing polar group") is preferable, a carboxy group or a hydroxyl group is more preferable, and a carboxy group is particularly preferable.

More specifically, an acid-decomposable group includes a group in which the polar group is protected by an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected by an acid-dissociable group).

Here, the term "acid dissociable group" means (i) a group having acid dissociation property that can cause the bond between the acid dissociable group and the atom adjacent to the acid dissociable group to cleave under the action of an acid, or (ii) an acid. It refers to both of the groups capable of cleaving the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group by further decarbonization reaction after partial bond cleavage by the action of.

The acid-dissociable group constituting the acid-decomposable group needs to be a group having a lower polarity than the polar group produced by the dissociation of the acid-dissociable group, whereby, when the acid-dissociable group is dissociated by the action of an acid, the acid-dissociable group A polar group with a higher polarity is formed, thereby increasing polarity. As a result, the polarity of the entire component (A1) increases. As the polarity increases, solubility in the developer is relatively changed, solubility increases when the developer is an alkali developer, and solubility decreases when the developer is an organic developer.

As an acid dissociable group, what has hitherto been proposed as an acid dissociable group of a base resin for a chemically amplified resist composition is mentioned.

As an acid dissociable group of the base resin for a chemically amplified resist composition, specifically, "acetal type acid dissociable group", "tertiary alkyl ester type acid dissociable group" described below, "class 3" And alkyloxycarbonyl acid dissociative groups.

· Acetal acid dissociation period:

As the acid dissociable group protecting the carboxyl group or hydroxyl group among the polar groups, for example, an acid dissociable group represented by the following general formula (a1-r-1) (hereinafter sometimes referred to as an "acetal acid dissociable group"). Can be mentioned.

[Formula 9]

[In the formula, Ra' ¹ and Ra' ² are hydrogen atoms or an alkyl group, Ra' ³ is a hydrocarbon group, and Ra' ³ may combine with any of Ra' ¹ and Ra' ² to form a ring.]

In the formula (a1-r-1), at least one of Ra' ¹ and Ra' ² is preferably a hydrogen atom, and more preferably both are hydrogen atoms.

When Ra' ¹ or Ra' ² is an alkyl group, in the description of the α-substituted acrylic acid ester, examples of the alkyl group include the same alkyl groups as the substituents which may be bonded to the carbon atom at the α position, and have 1 to 1 carbon atoms. The alkyl group of 5 is preferable. Specifically, a linear or branched chain alkyl group is preferably mentioned. More specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, etc. may be mentioned, and methyl group or ethyl group It is more preferable, and a methyl group is particularly preferable.

In the formula (a1-r-1), examples of the hydrocarbon group of Ra' ³ include a linear or branched chain alkyl group or a cyclic hydrocarbon group.

The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specifically, a methyl group, an ethyl group, n-propyl group, n-butyl group, n-pentyl group, etc. are mentioned. Among these, methyl group, ethyl group or n-butyl group is preferable, and methyl group or ethyl group is more preferable.

The branched chain alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specifically, isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group, 1,1-diethylpropyl group, 2,2-dimethylbutyl group, etc. are mentioned, and it is an isopropyl group It is preferred.

When Ra' ³ is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, or may be a polycyclic group or a monocyclic group.

As the aliphatic hydrocarbon group which is a monocyclic group, a group in which one hydrogen atom is removed from monocycloalkane is preferable. As the monocycloalkane, those having 3 to 6 carbon atoms are preferable, and specific examples thereof include cyclopentane and cyclohexane.

As an aliphatic hydrocarbon group which is a polycyclic group, a group in which one hydrogen atom is removed from polycycloalkane is preferable, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, and iso And bornan, tricyclodecane, and tetracyclododecane.

When the cyclic hydrocarbon group of Ra' ³ becomes an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring.

The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4 n + 2 π electrons, and may be monocyclic or polycyclic. It is preferable that carbon number of an aromatic ring is 5-30, 5-20 are more preferable, 6-15 are still more preferable, and 6-12 are especially preferable.

Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene and phenanthrene; And aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. As a hetero atom in an aromatic heterocycle, an oxygen atom, a sulfur atom, a nitrogen atom, etc. are mentioned. A pyridine ring, a thiophene ring, etc. are mentioned specifically, as an aromatic heterocycle.

Specifically as the aromatic hydrocarbon group for Ra' ³ , a group in which one hydrogen atom is removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group); A group in which one hydrogen atom is removed from an aromatic compound (eg, biphenyl, fluorene, etc.) containing two or more aromatic rings; A group in which one of the hydrogen atoms of the aromatic hydrocarbon ring or aromatic hetero ring is substituted with an alkylene group (for example, a benzyl group, a phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2 -Aryl alkyl groups, such as a naphthyl ethyl group, etc.) etc. are mentioned. The number of carbon atoms of the alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

When Ra' ³ combines with any one of Ra' ¹ and Ra' ² to form a ring, a 4- to 7-membered ring is preferable as the cyclic group, and a 4- to 6-membered ring is more preferable. A tetrahydropyranyl group, a tetrahydrofuranyl group, etc. are mentioned as a specific example of this cyclic group.

· Tertiary alkyl ester type acid dissociable groups:

Among the polar groups, examples of the acid-dissociable group protecting the carboxyl group include an acid-dissociable group represented by the following general formula (a1-r-2).

Moreover, among the acid dissociable groups represented by the following formula (a1-r-2), what is composed of an alkyl group is sometimes referred to as “third alkyl ester type acid dissociable group” for convenience.

[Formula 10]

[In the formula, Ra' ⁴ to Ra' ⁶ are each a hydrocarbon group, and Ra' ⁵ and Ra' ⁶ may combine with each other to form a ring.]

Hydrocarbon groups of Ra ^'4 ~ Ra' ^6, there may be mentioned the same ones as the Ra ^'3.

Ra ^'4 is preferably an alkyl group having 1 to 5 carbon atoms. When Ra' ⁵ and Ra' ⁶ combine with each other to form a ring, groups represented by the following general formula (a1-r2-1) can be mentioned. On the other hand, Ra ^'4 ~ Ra' ⁶ are not bonded to each other, and to, if an independent hydrocarbon group include groups represented by general formula (a1-r2-2).

[Formula 11]

[Wherein, Ra' ¹⁰ is an alkyl group having 1 to 10 carbon atoms, Ra' ¹¹ is a group forming an aliphatic cyclic group together with the carbon atom to which Ra' ¹⁰ is bonded, and Ra' ¹² to Ra' ¹⁴ are each independently a hydrocarbon group. Shows.]

In formula (a1-r2-1), the alkyl group having 1 to 10 carbon atoms in Ra' ¹⁰ is preferably a group raised as a straight or branched chain alkyl group of Ra' ³ in formula (a1-r-1). Do.

In the formula (a1-r2-1), the aliphatic cyclic group formed together with the carbon atom to which Ra' ¹¹ and Ra' ¹⁰ are bonded is a monocyclic group of Ra' ^{3 in} the formula (a1-r-1) or The group held as an aliphatic hydrocarbon group which is a cyclic group is preferable, and the group taken as aliphatic hydrocarbon group which is a monocyclic group is more preferable.

In formula (a1-r2-2), Ra' ¹² and Ra' ¹⁴ are preferably each independently an alkyl group having 1 to 10 carbon atoms, and the alkyl group is Ra' in formula (a1-r-1). ³ as a linear or branched alkyl group in all groups, and more preferably, be a linear alkyl group of 1 to 5 carbon atoms, and more preferably, particularly preferably methyl or ethyl.

In formula (a1-r2-2), Ra' ¹³ is a linear or branched chain alkyl group, monocyclic group, or polycyclic group exemplified as a hydrocarbon group of Ra' ³ in formula (a1-r-1). It is preferable that it is an aliphatic hydrocarbon group. Among these, a monocyclic or polycyclic group sentence aliphatic hydrocarbon group of Ra ^'3 is more preferably any group.

The specific example of the group represented by said formula (a1-r2-1) is given below. * Represents a bonding hand (hereinafter the same in this specification).

[Formula 12]

[Formula 13]

The specific example of the group represented by said formula (a1-r2-2) is given below.

[Formula 14]

· Tertiary alkyloxycarbonyl acid dissociative group:

As the acid dissociable group protecting the hydroxyl group among the polar groups, for example, an acid dissociable group represented by the following general formula (a1-r-3) (hereinafter referred to as "tertiary alkyloxycarbonyl acid dissociable group" for convenience) There are).

[Formula 15]

[In the formula, Ra' ⁷ to Ra' ⁹ are each alkyl groups.]

In the formulas (a1-r-3), Ra' ⁷ to Ra' ⁹ are preferably alkyl groups having 1 to 5 carbon atoms, and more preferably 1 to 3 carbon atoms.

Moreover, the total carbon number of each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4.

Among the above, the acid-decomposable group in the structural unit (a1) is preferably a group containing an aliphatic cyclic group, and a polar group (carboxy group) , Hydroxyl group, amino group, sulfo group, and the like) are more preferable. Among these, the acid-decomposable group in the structural unit (a1) contains an acid-dissociable group represented by the general formula (a1-r2-1) in that resolution is improved and a pattern having a better shape is easily formed. The group to be said is preferable, and the group containing the acid dissociable group represented by the following general formula (a1-r2-11) is more preferable.

[Formula 16]

[In the formula, Ra ^'10 is a hydrocarbon group of 1 to 10 carbon atoms. Ra" ¹¹ is a group forming a monocyclic aliphatic cyclic group together with the carbon atom to which Ra' ¹⁰ is bonded. * is a bonding hand.]

In the formula (a1-r2-11), the alkyl group having 1 to 10 carbon atoms in Ra' ¹⁰ is preferably a group raised as a straight or branched chain alkyl group of Ra' ³ in formula (a1-r-1). Do.

The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specifically, a methyl group, an ethyl group, n-propyl group, n-butyl group, n-pentyl group, etc. are mentioned. Among these, methyl group, ethyl group or n-butyl group is preferable, and methyl group or ethyl group is more preferable.

The branched chain alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specifically, isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group, 1,1-diethylpropyl group, 2,2-dimethylbutyl group, etc. are mentioned, and it is an isopropyl group It is preferred.

In the formula (a1-r2-11), the aliphatic cyclic group formed together with the carbon atom to which Ra" ¹¹ and Ra' ¹⁰ are bonded is an aliphatic hydrocarbon that is a monocyclic group of Ra' ^{3 in} the formula (a1-r-1). Groups raised as groups are preferred.

As the aliphatic hydrocarbon group which is a monocyclic group, a group in which one hydrogen atom is removed from monocycloalkane is preferable. As the monocycloalkane, those having 3 to 8 carbon atoms are preferable, those having 3 to 6 carbon atoms are more preferable, and specific examples thereof include cyclopentane and cyclohexane.

As the structural unit (a1), a hydrogen atom bonded to a carbon atom at the α position may be substituted with a substituent, a structural unit derived from an acrylic acid ester, a structural unit derived from acrylamide, or a component derived from hydroxystyrene or a hydroxystyrene derivative At least a part of the hydrogen atom in the -C(=O)-OH of a structural unit derived from a vinylbenzoic acid or a vinylbenzoic acid derivative in which at least a part of the hydrogen atom in the hydroxyl group of the unit is protected by an acid dissociable group And structural units protected by an acid-dissociable group.

As the structural unit (a1), among the above, a structural unit derived from an acrylic acid ester in which a hydrogen atom bonded to a carbon atom at the α position may be substituted with a substituent is preferable.

As a preferable specific example of such a structural unit (a1), the structural unit represented by the following general formula (a1-1) or general formula (a1-2) is mentioned.

[Formula 17]

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Va ¹ is a divalent hydrocarbon group which may have an ether bond, n _a1 is 0 to 2, and Ra ¹ is an acid dissociable group represented by the formulas (a1-r-1) or (a1-r-2). Wa ¹ is n _a2 + monovalent hydrocarbon group, n _a2 is 1 to 3, Ra ² is an acid dissociable group represented by the formula (a1-r-1) or (a1-r-3).]

In the formula (a1-1), the alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched chain alkyl group having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl Group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. 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.

As R, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms is preferable, and from the ease of industrial availability, a hydrogen atom or a methyl group is most preferred.

In the formula (a1-1), the divalent hydrocarbon group in Va ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

The aliphatic hydrocarbon group as the divalent hydrocarbon group in Va ¹ may be saturated or unsaturated, and is preferably saturated.

As the aliphatic hydrocarbon group, more specifically, a straight-chain or branched-chain aliphatic hydrocarbon group, or an aliphatic hydrocarbon group containing a ring in the structure can be given.

The straight-chain or branched-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, more preferably 1 to 4, and most preferably 1 to 3.

As a linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specifically, a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) ₂ -], a trimethylene group [-( And CH ₂ ) ₃ -], tetramethylene group [-(CH ₂ ) ₄ -], and pentamethylene group [-(CH ₂ ) ₅ -].

As a branched-chain aliphatic hydrocarbon group, a branched-chain alkylene group is preferable, and specifically, -CH(CH ₃ )-, -CH(CH ₂ CH ₃ )-, -C(CH ₃ ) ₂ -, Alkyl methylene groups such as -C(CH ₃ )(CH ₂ CH ₃ )-, -C(CH ₃ )(CH ₂ CH ₂ CH ₃ )-, -C(CH ₂ CH ₃ ) _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 -, -C(CH ₂ CH ₃ ) alkyl ethylene groups such as ₂ -CH ₂ -; Alkyltrimethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ -; And an alkylalkylene group such as an alkyltetramethylene group such as -CH(CH ₃ )CH ₂ CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ CH ₂ -, and the like. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

As the aliphatic hydrocarbon group containing a ring in the above structure, an alicyclic hydrocarbon group (a group in which two hydrogen atoms are removed from an aliphatic hydrocarbon ring) and an alicyclic hydrocarbon group are bonded to the ends of a straight-chain or branched-chain aliphatic hydrocarbon group. And a group interposed in the middle of a linear or branched aliphatic hydrocarbon group of an alicyclic hydrocarbon group. Examples of the linear or branched-chain aliphatic hydrocarbon group include the same as the straight-chain aliphatic hydrocarbon group or the branched-chain aliphatic hydrocarbon group.

The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms.

The alicyclic hydrocarbon group may be polycyclic or monocyclic. As the monocyclic alicyclic hydrocarbon group, a group in which two hydrogen atoms are removed from monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. As the polycyclic alicyclic hydrocarbon group, a group in which two hydrogen atoms are removed from polycycloalkane is preferable, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, and iso And bornan, tricyclodecane, and tetracyclododecane.

The aromatic hydrocarbon group as a divalent hydrocarbon group in Va ¹ is a hydrocarbon group having an aromatic ring.

The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, still more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. However, it is assumed that the carbon number in the substituent is not included in the carbon number.

As an aromatic ring which an aromatic hydrocarbon group has, specifically, aromatic hydrocarbon rings, such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; And aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. As a hetero atom in an aromatic heterocycle, an oxygen atom, a sulfur atom, a nitrogen atom, etc. are mentioned.

Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms are removed from the aromatic hydrocarbon ring (arylene group); A group in which one of the hydrogen atoms of the group (aryl group) in which one hydrogen atom is removed from the aromatic hydrocarbon ring is substituted with an alkylene group (for example, a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group) , A group in which one additional hydrogen atom has been removed from an aryl group in an arylalkyl group such as 1-naphthylethyl group and 2-naphthylethyl group). The number of carbon atoms of the alkylene group (alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

In the formula (a1-2), the n _a2 + monovalent hydrocarbon group in Wa ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity, and may be saturated, unsaturated, or usually saturated. The aliphatic hydrocarbon group is a combination of a straight chain or branched chain aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, or a straight chain or branched chain aliphatic hydrocarbon group and a aliphatic hydrocarbon group containing a ring in the structure. One can be lifted.

As for the said _a2 +1 value, 2-4 valence is preferable, and 2 or 3 valence is more preferable.

The specific example of the structural unit represented by said Formula (a1-1) is shown below. In the formulas below, R ^α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[Formula 18]

[Formula 19]

[Formula 20]

[Formula 21]

[Formula 22]

Below, the specific example of the structural unit represented by said Formula (a1-2) is shown.

[Formula 23]

Roneun structural unit (a1), among them, the structural units represented by formula (a1-1), and more preferably, among these, a structural unit represented by formula (a1-1), Ra ¹ is the formula (a1 The structural unit which is an acid dissociable group represented by -r2-11) is particularly preferable.

(A1) The structural unit (a1) which a component has may be 1 type, or 2 or more types may be sufficient as it.

The proportion of the structural unit (a1) in the component (A1) is preferably 5 to 20 mol%, more preferably 7 to 20 mol%, relative to the total structural unit (100 mol%) constituting the component (A1), 10-20 mol% is more preferable.

By setting the ratio of the structural unit (a1) to the lower limit or higher in the above-described preferred range, a resist pattern can be easily obtained, resolution is further improved, and a pattern having a good shape is easily formed. Moreover, by setting below an upper limit, it can balance with other structural units.

・For other components:

In addition to the structural unit (a10), the structural unit (a4), and the structural unit (a1), the component (A1) may have other structural units as necessary.

Other structural units may be, for example, a lactone-containing cyclic group, -SO ₂ - the structural unit (a2) containing a cyclic group containing or a carbonate-containing cyclic group; Structural unit (a3) containing a polar group-containing aliphatic hydrocarbon group (however, except for the structural unit (a1) or structural unit (a2)); And structural units derived from styrene or derivatives thereof.

·Constituent unit (a2)

The component (A1) is, in addition to the structural unit (a10), the structural unit (a4), and the structural unit (a1), if necessary, a lactone-containing cyclic group, a -SO ₂ -containing cyclic group, or a carbonate-containing cyclic group. You may have the structural unit (a2) containing the.

The lactone-containing cyclic group, -SO ₂ -containing cyclic group, or carbonate-containing cyclic group of the structural unit (a2) is effective in increasing the adhesion of the resist film to the substrate when the component (A1) is used for forming the resist film. will be. In addition, by having the structural unit (a2), in the alkali developing process, the solubility of the resist film in the alkali developing solution increases during development.

The "lactone-containing cyclic group" refers to a cyclic group containing a ring (lactone ring) containing -O-C(=O)- in the ring skeleton. The lactone ring is counted as the first ring, and if it is only a lactone ring, it is referred to as a monocyclic group, and when having another ring structure, it is referred to as a polycyclic group regardless of its structure. The lactone-containing cyclic group may be either a monocyclic group or a polycyclic group.

As the lactone-containing cyclic group in the structural unit (a2), any one can be used without particular limitation. Specifically, groups represented by the following general formulas (a2-r-1) to (a2-r-7) are listed.

[Formula 24]

[Wherein, Ra 'is ^21, each independently, a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR ", -OC (= O ) R", hydroxy group or cyano group; R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a -SO ₂ -containing cyclic group. A" may contain an oxygen atom (-O-) or a sulfur atom (-S-) It is a C1-C5 alkylene group, an oxygen atom, or a sulfur atom. n'is an integer from 0 to 2, and m'is 0 or 1.]

In the formulas (a2-r-1) to (a2-r-7), as the alkyl group for Ra' ²¹ , an alkyl group having 1 to 6 carbon atoms is preferable. It is preferable that the alkyl group is linear or branched chain. Specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group and the like can be mentioned. Among these, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.

Ra 'The alkoxy group in ²¹ is preferably an alkoxy group having 1 to 6 carbon atoms.

It is preferable that the alkoxy group is linear or branched chain. Specific examples include an alkyl group and is either an oxygen atom (-O-) in the alkyl group as the Ra ^'21 is connected.

Ra 'is a halogen atom in the ^21, and a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a fluorine atom is preferable.

Ra 'with a halogenated alkyl group in the ^21, wherein Ra' may be a group in which some or all of the hydrogen atoms of the alkyl group in ²¹ with the halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferable, and a perfluoroalkyl group is particularly preferable.

In the ^{Ra '21 -COOR ", -OC (} = O) R" in, R "is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or -SO ₂ - containing a cyclic group.

The alkyl group for R" may be either a straight chain, a branched chain, or a cyclic, and preferably 1 to 15 carbon atoms.

When R" is a linear or branched chain alkyl group, it is preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group.

When R" is a cyclic alkyl group, it is preferably 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and even more preferably 5 to 10 carbon atoms. Specifically, substitution with a fluorine atom or a fluorinated alkyl group A group in which one or more hydrogen atoms are removed from monocycloalkanes which may or may not be used; groups in which one or more hydrogen atoms are removed from polycycloalkanes such as bicycloalkane, tricycloalkane and tetracycloalkane, etc. More specifically, groups in which one or more hydrogen atoms are removed from monocycloalkanes such as cyclopentane and cyclohexane; adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc. And groups in which one or more hydrogen atoms have been removed from polycycloalkane.

Examples of the lactone-containing cyclic group for R" include the same groups as the groups represented by the general formulas (a2-r-1) to (a2-r-7).

The carbonate-containing cyclic group in R" is the same as the carbonate-containing cyclic group described later, specifically, groups represented by general formulas (ax3-r-1) to (ax3-r-3).

R "-SO ₂ of the-containing cyclic group, which will be described later -SO ₂ - containing cyclic group with the same and, specifically, each by the formula (a5-r-1) ~ (a5-r-4) The group represented is mentioned.

Ra 'hydroxy group in ²¹ is preferably a carbon number of 1 to 6, and specifically, the Ra' at least one of the hydrogen atoms of the alkyl group in ²¹ is may be a group substituted with a hydroxyl group.

In the general formulas (a2-r-2), (a2-r-3) and (a2-r-5), the alkylene group having 1 to 5 carbon atoms in A" is a straight chain or branched chain. The alkylene group is preferable, and examples thereof include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, etc. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include the alkylene group. And a group in which -O- or -S- is interposed between the terminal or carbon atom of, for example, -O-CH ₂ -, -CH ₂ -O-CH ₂ -, -S-CH ₂ -,- CH ₂ -S-CH ₂ -etc. As A", an alkylene group having 1 to 5 carbon atoms or -O- is preferable, an alkylene group having 1 to 5 carbon atoms is more preferable, and a methylene group is most preferred. .

Below, specific examples of groups represented by the general formulas (a2-r-1) to (a2-r-7) are given.

[Formula 25]

[Formula 26]

The "-SO ₂ -containing cyclic group" refers to a cyclic group containing a ring containing -SO ₂ -in its ring skeleton, specifically, the sulfur atom (S) in -SO ₂ -is a cyclic group It is a cyclic group forming part of the ring skeleton. -SO ₂ -in the ring skeleton The ring to be included is counted as the first ring, and if it is only the ring, it is referred to as a monocyclic group, and when having another ring structure, it is referred to as a polycyclic group regardless of the structure. The -SO ₂ -containing cyclic group may be either a monocyclic group or a polycyclic group.

-SO ₂ - containing cyclic group are, in particular, the -O-SO ₂ in the ring skeleton-containing cyclic group, i.e., -O-SO ₂ - sultone (-OS- sultone to form a part of a ring in the skeleton ) It is preferable that it is a cyclic group containing a ring.

As the -SO ₂ -containing cyclic group, more specifically, groups represented by the following general formulas (a5-r-1) to (a5-r-4) are exemplified.

[Formula 27]

[Wherein, Ra' ⁵¹ is each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group or a cyano group. R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a -SO ₂ -containing cyclic group. A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, oxygen It is an atom or a sulfur atom.

n'is an integer from 0 to 2.]

In the general formulas (a5-r-1) to (a5-r-2), A" is the general formulas (a2-r-2), (a2-r-3), (a2-r-5) It is the same as A" in.

As the alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR", -OC(=O)R" and hydroxyalkyl group for Ra' ⁵¹ , the above-mentioned general formulas (a2-r-1) to (a2), respectively. The same thing as described in the description of Ra' ²¹ in -r-7) can be mentioned.

Below, specific examples of the groups represented by general formulas (a5-r-1) to (a5-r-4) are given. "Ac" in the formula represents an acetyl group.

[Formula 28]

[Formula 29]

[Formula 30]

The "carbonate-containing cyclic group" refers to a cyclic group containing a ring (carbonate ring) containing -O-C(=O)-O- in the ring skeleton. The carbonate ring is counted as the first ring, and if it is only a carbonate ring, it is referred to as a monocyclic group, and when having another ring structure, it is referred to as a polycyclic group regardless of its structure. The carbonate-containing cyclic group may be either a monocyclic group or a polycyclic group.

As the cyclic group containing a carbonate ring, any one can be used without particular limitation. Specifically, groups represented by the following general formulas (ax3-r-1) to (ax3-r-3) are listed.

[Formula 31]

[In formula, ^Ra'x31 is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group, respectively. R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a -SO ₂ -containing cyclic group. A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, It is an oxygen atom or a sulfur atom. p'is an integer from 0 to 3, and q'is 0 or 1.]

In the general formulas (ax3-r-2) to (ax3-r-3), A" is the general formulas (a2-r-2), (a2-r-3), (a2-r-5) It is the same as A" in.

Ra ^'31 alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, -COOR in ", -OC (= O) R ", a hydroxyl group, each of the above general formula (a2-r-1) ~ (a2 The same thing as described in the description of Ra' ²¹ in -r-7) can be mentioned.

Below, specific examples of the groups represented by the general formulas (ax3-r-1) to (ax3-r-3) are given.

[Formula 32]

As the structural unit (a2), a structural unit derived from an acrylic acid ester in which a hydrogen atom bonded to a carbon atom at the α position may be substituted with a substituent is particularly preferable.

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

[Formula 33]

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Ya ²¹ is a single bond or a divalent linking group. La ²¹ is -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, and R'represents a hydrogen atom or a methyl group. However, when La ²¹ is -O-, Ya ²¹ does not become -CO-. Ra ²¹ is a lactone-containing cyclic group, -SO ₂ -containing cyclic group or carbonate-containing cyclic group.]

In the formula (a2-1), R is as defined above.

As R, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms is preferable, and from the ease of industrial availability, a hydrogen atom or a methyl group is particularly preferable.

In the formula (a2-1), the divalent linking group of Ya ²¹ is not particularly limited, and examples thereof include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and the like.

As a divalent hydrocarbon group in Ya ²¹ , the same thing as the group mentioned in the description of the divalent hydrocarbon group in Va ¹ in the formula (a1-1) described above can be mentioned. Examples of the substituent which the divalent hydrocarbon group in Ya ²¹ may have include a C 1 to C 5 alkyl group, an alkoxy group, a halogen atom, a C 1 to C 5 halogenated alkyl group, a hydroxyl group, and a carbonyl group.

Preferred divalent linking groups containing a hetero atom in Ya ²¹ are, for example, -O-, -C(=O)-O-, -C(=O)-, -OC(=O )-O-, -C(=O)-NH-, -NH-, -NH-C(=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-, general formula -Y ²¹ -OY ²² -, -Y ²¹ -O-, -Y ²¹ -C(=O)-O-, -C(=O)-OY ²¹ -, -[Y ²¹ -C(=O)-O] _m" -Y ²² -, -Y ²¹ -OC(=O)-Y ²² -or -Y ²¹ -S (=O) A group represented by ₂ -OY ^22- [wherein Y ²¹ and Y ²² are bivalent hydrocarbon groups each independently having a substituent, O is an oxygen atom, and m" is an integer from 0 to 3 Etc.].

The divalent linking group containing the hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, -NH-C(=NH)- In that case, the H may be substituted with a substituent such as an alkyl group or an acyl group. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.

General formula -Y ²¹ -OY ²² -, -Y ²¹ -O-, -Y ²¹ -C(=O)-O-, -C(=O)-OY ²¹ -, -[Y ²¹ -C(=O )-O] _m" -Y ²² -, -Y ²¹ -OC(=O)-Y ²² -or -Y ²¹ -S(=O) ₂ -OY ²² -among, Y ²¹ and Y ²² are each independently It is a divalent hydrocarbon group which may have a substituent, and the bivalent hydrocarbon group is the same as the one described in the description as the divalent linking group (a divalent hydrocarbon group which may have a substituent).

As Y ²¹ , a straight-chain aliphatic hydrocarbon group is preferable, a straight-chain alkylene group is more preferable, and a C1-C5 straight-chain alkylene group is more preferable, and a methylene group or ethylene group is particularly preferable.

As Y ²² , a straight-chain or branched-chain aliphatic hydrocarbon group is preferable, and a methylene group, an ethylene group, or an alkylmethylene group is more preferable. 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.

In the group represented by the formula -[Y ²¹ -C(=O)-O] _m" -Y ²² -, m" is an integer from 0 to 3, preferably an integer from 0 to 2, more preferably 0 or 1 And 1 is particularly preferable. That is, as the group represented by the formula -[Y ²¹ -C(=O)-O] _m" -Y ²² -, the group represented by the formula -Y ²¹ -C(=O)-OY ²² -is particularly preferred. , The group represented by the formula -(CH ₂ ) _a'- C(=O)-O-(CH ₂ ) _b' -is preferable, wherein a'is an integer of 1 to 10, and is 1 to 8 An integer is preferred, an integer from 1 to 5 is more preferred, 1 or 2 is more preferred, and 1 is most preferred, b'is an integer from 1 to 10, an integer from 1 to 8 is preferred, 1 The integer of -5 is more preferable, 1 or 2 is still more preferable, and 1 is the most preferable.

Ya ²¹ is preferably a single bond, an ester bond [-C(=O)-O-], an ether bond (-O-), a linear or branched alkylene group, or a combination thereof.

In the formula (a2-1), La ²¹ is -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-.

R'represents a hydrogen atom or a methyl group.

However, when La ²¹ is -O-, Ya ²¹ does not become -CO-.

In the formula (a2-1), Ra ²¹ is a lactone-containing cyclic group, -SO ₂ -containing cyclic group, or carbonate-containing cyclic group.

The lactone-containing cyclic group, -SO ₂ -containing cyclic group, and carbonate-containing cyclic group in Ra ²¹ are each represented by the general formulas (a2-r-1) to (a2-r-7) described above, respectively. Groups, groups represented by formulas (a5-r-1) to (a5-r-4), and groups represented by formulas (ax3-r-1) to (ax3-r-3), respectively, are preferably mentioned. .

Among them, Ra ²¹ is preferably a lactone-containing cyclic group or a -SO ₂ -containing cyclic group, and the general formulas (a2-r-1), (a2-r-2), (a2-r-6) or The group represented by (a5-r-1) each is more preferable. Specifically, the above formulas (r-lc-1-1) to (r-lc-1-7), (r-lc-2-1) to (r-lc-2-18), (r-lc -6-1), (r-sl-1-1), (r-sl-1-18) Each group represented by each is more preferable.

(A1) The structural unit (a2) which a component has may be 1 type, or 2 or more types may be sufficient as it.

When the component (A1) has a structural unit (a2), the proportion of the structural unit (a2) is 1 to 80 mol% with respect to the total (100 mol%) of the total structural units constituting the component (A1) It is preferable, it is more preferable that it is 3 to 70 mol%, it is more preferable that it is 5 to 60 mol%, and it is still more preferable that it is 10 to 50 mol%.

If the ratio of the structural unit (a2) is equal to or more than the lower limit of the preferred range, the effect by containing the structural unit (a2) is sufficiently obtained. On the other hand, if it is equal to or less than the upper limit of the preferred range, balance with other structural units is obtained. It can be grasped, and various lithography characteristics and pattern shapes are improved.

·Constituent unit (a3)

The component (A1) may have, in addition to the structural unit (a10), the structural unit (a4), and the structural unit (a1), if necessary, a structural unit (a3) containing a polar group-containing aliphatic hydrocarbon group ((1)). However, any of the above-mentioned structural units (a0), structural units (a1), and structural units (a2) is excluded).

When the component (A1) has a structural unit (a3), the hydrophilicity of the component (A) is increased, contributing to the improvement of resolution.

Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, a hydroxyalkyl group in which a part of the hydrogen atoms of the alkyl group are substituted with fluorine atoms, and a hydroxyl group is particularly preferable.

Examples of the aliphatic hydrocarbon group include a straight-chain or branched-chain hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a cyclic aliphatic hydrocarbon group (cyclic group). As the cyclic group, a monocyclic group or a polycyclic group may be used, and for example, a resin for a resist composition for an ArF excimer laser can be appropriately selected and used. The cyclic group is preferably a polycyclic group, and more preferably 7 to 30 carbon atoms.

Especially, the structural unit derived from the acrylic acid ester containing the aliphatic polycyclic group containing the hydroxyalkyl group in which a part of the hydrogen atom of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with the 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, or the like. Specifically, groups in which two or more hydrogen atoms have been removed from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane are mentioned. Among these polycyclic groups, a group in which two or more hydrogen atoms are removed from adamantane, a group in which two or more hydrogen atoms are removed from norbornane, and a group in which two or more hydrogen atoms are removed from tetracyclododecane are industrially preferred.

As a structural unit (a3), if it contains a polar group containing aliphatic hydrocarbon group, arbitrary thing can be used without being specifically limited.

As a structural unit (a3), the hydrogen atom couple|bonded with the carbon atom of the (alpha) position is a structural unit derived from the acrylic acid ester which may be substituted with the substituent, and the structural unit containing a polar group-containing aliphatic hydrocarbon group is preferable.

As a structural unit (a3), when the hydrocarbon group in a polar group-containing aliphatic hydrocarbon group is a C1-C10 linear or branched chain hydrocarbon group, the structural unit derived from hydroxyethyl ester of acrylic acid is preferable, When the hydrocarbon group is a polycyclic group, structural units represented by the following formula (a3-1), structural units represented by the formula (a3-2), and structural units represented by the formula (a3-3) are exemplified.

[Formula 34]

[Wherein, R is the same as above, j is an integer from 1 to 3, k is an integer from 1 to 3, t'is an integer from 1 to 3, l is an integer from 1 to 5, and s is It is an integer of 1-3.]

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 positions 3 and 5 of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the adamantyl group at the 3 position.

It is preferable that j is 1, and it is especially preferable that a hydroxyl group couple|bonds with the 3 position of adamantyl group.

In formula (a3-2), it is preferable that k is 1. It is preferable that the cyano group is bonded to the 5 or 6 position of the norbornyl group.

In formula (a3-3), t'is preferably 1. It is preferable that l is 1. It is preferable that s is 1. It is preferable that a 2-norbornyl group or a 3-norbornyl group is bonded to the terminal of the carboxyl group of acrylic acid. It is preferable that the fluorinated alkyl alcohol is bonded to the 5 or 6 position of the norbornyl group.

(A1) The structural unit (a3) which a component has may be 1 type, or 2 or more types may be sufficient as it.

(A1) When a component has a structural unit (a3), the ratio of the structural unit (a3) is 1-50 mol% with respect to the total (100 mol%) of all the structural units which comprise the said (A1) component. It is preferable, it is more preferable that it is 3-40 mol%, it is more preferable that it is 5-30 mol%, and 10-30 mol% is especially preferable.

When the ratio of the structural unit (a3) is equal to or more than a preferable lower limit, resolution in forming a resist pattern becomes higher. On the other hand, by setting it below a preferable upper limit, it becomes easy to balance with other structural units.

Structural unit derived from styrene or its derivatives (structural unit (st))

"Styrene" is a concept including styrene and those in which the hydrogen atom at the α-position of styrene is substituted with a substituent such as an alkyl group or a halogenated alkyl group. The alkyl group as a substituent here includes an alkyl group having 1 to 5 carbon atoms, and the halogenated alkyl group as the substituent group includes a halogenated alkyl group having 1 to 5 carbon atoms.

Examples of the "styrene derivative" include a substituent bonded to a benzene ring of styrene in which the hydrogen atom at the α position may be substituted with a substituent.

Note that the α position (the carbon atom at the α position) refers to a carbon atom to which the benzene ring is attached, unless otherwise specified.

"Structural units derived from styrene" and "structural units derived from styrene derivatives" refer to structural units formed by cleavage of ethylenic double bonds of styrene or styrene derivatives.

The structural unit (st) possessed by the component (A1) may be one type or two or more types.

(A1) When a component has a structural unit (st), the ratio of the structural unit (st) is 1-30 mol% with respect to the total (100 mol%) of all the structural units which comprise the (A1) component It is preferable, and it is more preferable that it is 3 to 20 mol%.

In the resist composition of the present embodiment, the resin component that is the component (A1) has a structural unit (a10), a structural unit (a4), and a structural unit (a1), and one type of polymer may be used alone, You may use 2 or more types together.

As a preferable (A1) component, the copolymer which has a structural unit (a10), a structural unit (a4), and a structural unit (a1) is mentioned, Especially, a structural unit (a10), a structural unit (a4), and a structural unit The copolymer composed of (a1) is particularly preferred.

The weight average molecular weight (Mw) of the component (A1) (based on polystyrene conversion by gel permeation chromatography (GPC)) is preferably 5000 to 30000, more preferably 6000 to 25000, and even more preferably 10000 to 20000 .

When the Mw of the component (A1) is equal to or less than the upper limit of the preferred range, it becomes easy to suppress the viscosity of the resist composition from becoming too high. Moreover, if it has solubility in a resist solvent sufficient for use as a resist, and is at least the lower limit of the preferred range, a resist film having a high film thickness is easily formed. Moreover, the dry etching resistance and the cross-sectional shape of the resist pattern become better.

The dispersion degree (Mw/Mn) of the component (A1) is not particularly limited, and 1.0 to 4.0 is preferable, 1.0 to 3.0 is more preferable, and 1.5 to 2.5 is particularly preferable. In addition, Mn represents the number average molecular weight.

The component (A1) includes, for example, a monomer that induces the structural unit (a10) (a monomer in which at least a part of a hydrogen atom in a hydroxyl group bonded to a benzene ring is protected), and a monomer that induces the structural unit (a4). , A monomer inducing the structural unit (a1) and, if necessary, a monomer inducing the other structural unit in a polymerization solvent, wherein, for example, azobisisobutyronitrile (AIBN), azobisisobutyric acid dimethyl (For example, V-601, etc.) It can manufacture by adding and polymerizing a radical polymerization initiator, and then performing a deprotection reaction.

Further, during polymerization, for example, by using a chain transfer agent such as HS-CH ₂ -CH ₂ -CH ₂ -C(CF ₃ ) ₂ -OH in combination, -C(CF ₃ ) ₂ -OH at the terminal. You may introduce a flag. As described above, the copolymer in which a hydroxyalkyl group in which a part of the hydrogen atom of the alkyl group is substituted with a fluorine atom is introduced is effective in reducing development defects and reducing LER (line edge roughness: uneven irregularities on the line sidewalls).

As the component (A1) contained in the resist composition, one type may be used alone, or two or more types may be used in combination.

The proportion of the component (A1) in the component (A) is preferably 25% by mass or more, more preferably 50% by mass or more, even more preferably 75% by mass or more, based on the total mass of the component (A), 100 It may be mass%. When the proportion of the component (A1) is greater than or equal to the lower limit of the above-mentioned preferred range, a resist pattern of good shape, which is excellent in high sensitivity, resolution, dimensional uniformity (CDU) in the support surface (Shot), and other lithography characteristics, is easily formed. .

The component (A) in the resist composition of the present embodiment is a resin component whose solubility in a developer is changed by the action of an acid, and may contain resin components other than the component (A1).

In the resist composition of the present embodiment, the content of the component (A) may be appropriately adjusted depending on the thickness of the resist film to be formed or the like.

≪Other ingredients≫

The resist composition of the present embodiment may further contain components other than the component (A) in addition to the component (A) described above. As other components, (B) component, (D) component, (E) component, (F) component, (S) component, etc. which are shown below are mentioned, for example.

About the acid generator component (B)

The resist composition of the present embodiment may further contain an acid generator component (hereinafter referred to as "(B) component") in addition to the component (A).

(B) As a component, it is not specifically limited, So far, what has been proposed as an acid generator for chemically amplified resist can be used.

Examples of such an acid generator include an onium salt acid generator such as an iodonium salt or a sulfonium salt, and an oxime sulfonate acid generator; Diazomethane-based acid generators such as bisalkyl or bisarylsulfonyldiazomethanes and poly(bissulfonyl)diazomethanes; And nitrobenzyl sulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators. Among them, it is preferable to use an onium salt-based acid generator.

As an onium salt-based acid generator, for example, a compound represented by the following general formula (b-1) (hereinafter also referred to as a "(b-1) component"), a compound represented by the general formula (b-2) (hereinafter "( b-2) component” or a compound represented by general formula (b-3) (hereinafter also referred to as “(b-3) component”) can be used.

[Formula 35]

[Wherein, R ¹⁰¹ , R ¹⁰⁴ to R ¹⁰⁸ are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. R ¹⁰⁴ and R ¹⁰⁵ may be bonded to each other to form a ring.

R ¹⁰² is a fluorine atom or a C1-C5 fluorinated alkyl group. Y ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom. V ¹⁰¹ to V ¹⁰³ are each independently a single bond, an alkylene group, or a fluorinated alkylene group. L ¹⁰¹ to L ¹⁰² are each independently a single bond or an oxygen atom. L ¹⁰³ to L ¹⁰⁵ are each independently a single bond, -CO- or -SO ₂ -. m is an integer of 1 or more, and M'm ⁺ is an onium cation of m value.]

{Noonbu}

・(B-1) Anion part of component

In formula (b-1), R ¹⁰¹ is a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain-type alkenyl group which may have a substituent.

A cyclic group which may have a substituent:

The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity. Moreover, an aliphatic hydrocarbon group may be saturated or unsaturated, and it is preferable that it is usually saturated.

The aromatic hydrocarbon group for R ¹⁰¹ is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. . However, it is assumed that the carbon number in the substituent is not included in the carbon number.

As an aromatic ring of the aromatic hydrocarbon group in R ¹⁰¹ , specifically, benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, or an aromatic heterocycle in which a part of the carbon atoms constituting these aromatic rings is substituted with a hetero atom And the like. As a hetero atom in an aromatic heterocycle, an oxygen atom, a sulfur atom, a nitrogen atom, etc. are mentioned.

Specifically as an aromatic hydrocarbon group for R ¹⁰¹ , a group in which one hydrogen atom is removed from the aromatic ring (aryl group: for example, a phenyl group, a naphthyl group, etc.), and one of the hydrogen atoms in the aromatic ring is substituted with an alkylene group And an aryl alkyl group such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, and the like. The number of carbon atoms of the alkylene group (alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

The cyclic aliphatic hydrocarbon group for R ¹⁰¹ includes an aliphatic hydrocarbon group containing a ring in the structure.

As the aliphatic hydrocarbon group containing a ring in this structure, an alicyclic hydrocarbon group (a group in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring) and an alicyclic hydrocarbon group bonded to the terminal of a straight-chain or branched-chain aliphatic hydrocarbon group And a group interposed in the middle of a linear or branched aliphatic hydrocarbon group of an alicyclic hydrocarbon group.

The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms.

The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic alicyclic hydrocarbon group, a group in which one or more hydrogen atoms are removed from monocycloalkane is preferable. As the monocycloalkane, those having 3 to 6 carbon atoms are preferable, and specific examples thereof include cyclopentane and cyclohexane. As the polycyclic alicyclic hydrocarbon group, a group in which one or more hydrogen atoms are removed from polycycloalkane is preferable, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among them, as the polycycloalkane, polycycloalkane having a polycyclic skeleton of a crosslinked ring system such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane; A polycycloalkane having a condensed cyclic polycyclic skeleton such as a cyclic group having a steroid skeleton is more preferable.

Especially, as the cyclic aliphatic hydrocarbon group for R ¹⁰¹ , a group in which one or more hydrogen atoms are removed from monocycloalkane or polycycloalkane is preferable, and a group in which one hydrogen atom is removed from polycycloalkane is more preferable, and Adama A til group and a norbornyl group are particularly preferred, and an adamantyl group is most preferred.

The straight-chain or branched-chain aliphatic hydrocarbon group, which may be bonded to an alicyclic hydrocarbon group, preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, and more preferably 1 carbon atom. -3 is particularly preferable.

As a linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specifically, a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) ₂ -], a trimethylene group [-( And CH ₂ ) ₃ -], tetramethylene group [-(CH ₂ ) ₄ -], and pentamethylene group [-(CH ₂ ) ₅ -].

As a branched-chain aliphatic hydrocarbon group, a branched-chain alkylene group is preferable, and specifically, -CH(CH ₃ )-, -CH(CH ₂ CH ₃ )-, -C(CH ₃ ) ₂ -, Alkyl methylene groups such as -C(CH ₃ )(CH ₂ CH ₃ )-, -C(CH ₃ )(CH ₂ CH ₂ CH ₃ )-, -C(CH ₂ CH ₃ ) _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 -, -C(CH ₂ CH ₃ ) alkyl ethylene groups such as ₂ -CH ₂ -; Alkyltrimethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ -; And an alkylalkylene group such as an alkyltetramethylene group such as -CH(CH ₃ )CH ₂ CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ CH ₂ -, and the like. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

Moreover, the cyclic hydrocarbon group in R ¹⁰¹ may contain a hetero atom like a heterocycle. Specifically, each of the lactone-containing cyclic groups represented by the general formulas (a2-r-1) to (a2-r-7), and the general formulas (a5-r-1) to (a5-r-4), respectively. And -SO ₂ -containing cyclic groups represented, and other heterocyclic groups represented by the following formulas (r-hr-1) to (r-hr-16).

[Formula 36]

As a substituent in the cyclic group of R ¹⁰¹ , an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, etc. are mentioned, for example.

As the alkyl group as the substituent, an alkyl group having 1 to 5 carbon atoms is preferable, and a methyl group, ethyl group, propyl group, n-butyl group and tert-butyl group are most preferred.

As the alkoxy group as a substituent, an alkoxy group having 1 to 5 carbon atoms is preferable, a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group are more preferable, and a methoxy group , Ethoxy group is most preferred.

A fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned as a halogen atom as a substituent, and a fluorine atom is preferable.

Examples of the halogenated alkyl group as a substituent include an alkyl group having 1 to 5 carbon atoms, for example, a group in which part or all of the hydrogen atoms such as methyl group, ethyl group, propyl group, n-butyl group and tert-butyl group are substituted with the halogen atom. have.

The carbonyl group as a substituent is a group that substitutes a methylene group (-CH ₂ -) constituting a cyclic hydrocarbon group.

Chain type alkyl group which may have a substituent:

The chain alkyl group of R ¹⁰¹ may be either straight chain or branched chain.

As a linear alkyl group, it is preferable that carbon number is 1-20, it is more preferable that it is 1-15 carbon atoms, and carbon number 1-10 is most preferable. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decanyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group , Tetradecyl group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henicosyl group, docosyl group and the like.

The branched chain 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, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, and the like.

Chain alkenyl group which may have a substituent:

The chain alkenyl group of R ¹⁰¹ may be either a straight chain or a branched chain, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, and even more preferably 2 to 4 carbon atoms. And 3 carbon atoms is particularly preferable. As a linear alkenyl group, vinyl group, propenyl group (allyl group), butynyl group etc. are mentioned, for example. Examples of the branched chain alkenyl group include 1-methylvinyl group, 2-methylvinyl group, 1-methylpropenyl group, 2-methylpropenyl group, and the like.

As the chain-type alkenyl group, among the above, a straight-chain alkenyl group is preferable, a vinyl group and a propenyl group are more preferable, and a vinyl group is particularly preferable.

Examples of the substituent in the chained alkyl group or alkenyl group of R ¹⁰¹ include, for example, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and a cyclic group in R ¹⁰¹ above. Can.

Especially, R ¹⁰¹ is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, for example, a group in which one or more hydrogen atoms are removed from a phenyl group, a naphthyl group, or polycycloalkane; Lactone-containing cyclic groups represented by the general formulas (a2-r-1) to (a2-r-7), respectively; The -SO ₂ -containing cyclic groups represented by the general formulas (a5-r-1) to (a5-r-4), respectively, are preferred.

In the formula (b-1), Y ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom.

If the Y ¹⁰¹ 2-valent connecting group containing an oxygen atom, and Y is ^101, it may contain an atom other than an oxygen atom. As an atom other than an oxygen atom, a carbon atom, a hydrogen atom, a sulfur atom, a nitrogen atom, etc. are mentioned, for example.

As a divalent linking group containing an oxygen atom, for example, an oxygen atom (ether bond: -O-), ester bond (-C(=O)-O-), oxycarbonyl group (-OC(=O)- ), amide bond (-C(=O)-NH-), carbonyl group (-C(=O)-), carbonate bond (-OC(=O)-O-), etc. ; And combinations of the non-hydrocarbon-based oxygen atom-containing linking group with an alkylene group. A sulfonyl group (-SO ₂ -) may be further connected to this combination. Examples of the divalent linking group containing such an oxygen atom include linking groups represented by the following general formulas (y-al-1) to (y-al-7), respectively.

[Formula 37]

Wherein, V ^'101 is a single bond or an alkylene group having a carbon number of 1 to 5, V' ¹⁰² is a divalent saturated hydrocarbon group having a carbon number of 1 to 30.]

V 'group is a divalent saturated hydrocarbon group of the ^102, preferably an alkylene group of 1 to 30 carbon atoms, more preferably an alkylene group of 1 to 10 carbon atoms, more preferably an alkylene group of 1 to 5 carbon atoms.

V alkylene group in the ^'101 and V' is ^102, and the contribution of the linear alkylene is alkylene contribution of the branched, is preferably an alkylene group of a linear.

V as an alkylene group in the ^"101 and V" ^102, specifically, 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 Alkyl methylene groups such as CH ₂ CH ₃ )- and -C(CH ₂ CH ₃ ) ₂ -; Ethylene group [-CH ₂ CH ₂ -]; Alkyl ethylene 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- ; Trimethylene group (n-propylene group) [-CH ₂ CH ₂ CH ₂ -]; Alkyltrimethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ -; Tetramethylene group [-CH ₂ CH ₂ CH ₂ CH ₂ -]; Alkyl tetramethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ CH ₂ -; And a pentamethylene group [-CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -].

In addition, or may V 'or ¹⁰¹ V' ¹⁰² portion of the methylene groups in the alkylene groups of the, optionally substituted by a divalent aliphatic cyclic group with a carbon number of 5-10. The said aliphatic cyclic group further removed one hydrogen atom from the cyclic aliphatic hydrocarbon group (monocyclic alicyclic hydrocarbon group, polycyclic alicyclic hydrocarbon group) in R ¹⁰¹ in said formula (b-1). A divalent group is preferable, and a cyclohexylene group, 1,5-adamantylene group or 2,6-adamantylene group is more preferable.

As Y ¹⁰¹ , a divalent linking group containing an ester bond or a divalent linking group containing an ether bond is preferable, and the linking groups represented by the formulas (y-al-1) to (y-al-5) are more preferable. Do.

In formula (b-1), V ¹⁰¹ is a single bond, an alkylene group, or a fluorinated alkylene group. It is preferable that the alkylene group and fluorinated alkylene group in V ¹⁰¹ have 1 to 4 carbon atoms. A fluorinated alkylene group in the V ¹⁰¹ is, a part or all of the hydrogen atoms of the alkylene group of the ¹⁰¹ V may be substituted with a fluorine atom. Among these, V ¹⁰¹ is preferably a single bond, or a fluorinated alkylene group having from 1 to 4 carbon atoms.

In formula (b-1), R ¹⁰² is a fluorine atom or a C1-C5 fluorinated alkyl group. R ¹⁰² is preferably a fluorine atom or a C 1 to C 5 perfluoroalkyl group, and more preferably a fluorine atom.

(b-1) As a specific example of the anion part of a component, when Y ¹⁰¹ becomes a single bond, fluorinated alkyl sulfo, such as trifluoromethanesulfonate anion and perfluorobutanesulfonate anion, for example Nate anion; When Y ¹⁰¹ is a divalent linking group containing an oxygen atom, anions represented by any of the following formulas (an-1) to (an-3) can be exemplified.

[Formula 38]

[Wherein, R" ¹⁰¹ is an aliphatic cyclic group which may have a substituent, a group represented by each of the formulas (r-hr-1) to (r-hr-6), or a chain alkyl group which may have a substituent. R<^102> is an aliphatic cyclic group which may have a substituent, a lactone-containing cyclic group represented by the general formulas (a2-r-1) to (a2-r-7), or the general formula (a5-r). -1) to -SO ₂ -containing cyclic groups each represented by (a5-r-4); R" ¹⁰³ is an aromatic cyclic group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkenyl group which may have a substituent; v" is an integer of 0 to 3 each independently, q "Is each independently an integer of 1 to 20, t" is an integer of 1 to 3, and n" is 0 or 1.]

R ^"101, R" ¹⁰² and R "aliphatic cyclic group which may have a ¹⁰³ substituent group is a group exemplified as the aliphatic hydrocarbon group of annular in said R ¹⁰¹ is preferably In the above substituents, R ¹⁰¹ The same thing as the substituent which may substitute for the cyclic aliphatic hydrocarbon group in the above is mentioned.

R "aromatic cyclic group which may have a substituent in the ¹⁰³ is preferably a group exemplified as the aromatic hydrocarbon group in groups hydrocarbons, cyclic in the above-mentioned R ^101. As the substituent of the R ¹⁰¹ The same thing as the substituent which may substitute the aromatic hydrocarbon group is mentioned.

The chain-like alkyl group which may have a substituent in R" ¹⁰¹ is preferably a group exemplified as the chain-like alkyl group in R ^101. Chain-like eggs which may have a substituent in R" ¹⁰³ It is preferable that a kenyl group is the group illustrated as the chain alkenyl group in said R ¹⁰¹ .

・(B-2) Anion part of component

In formula (b-2), R ¹⁰⁴ and R ¹⁰⁵ are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, The same thing as R ¹⁰¹ in Formula (b-1) is mentioned, respectively. However, R ¹⁰⁴ and R ¹⁰⁵ may be bonded to each other to form a ring.

R ¹⁰⁴ and R ¹⁰⁵ are preferably a chain-type alkyl group which may have a substituent, and more preferably a straight-chain or branched-chain alkyl group or a straight-chain or branched-chain fluorinated alkyl group.

The chain-like alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 7, and more preferably 1 to 3 carbon atoms. The carbon number of the chain alkyl group of R ¹⁰⁴ and R ¹⁰⁵ is preferably as small as possible, for the reason that the solubility in the solvent for resist is good within the range of the carbon number. Further, in the chain alkyl groups of R ¹⁰⁴ and R ^105, the more hydrogen atoms substituted with fluorine atoms, the stronger the strength of the acid, and the higher the transparency to high energy light and electron beams of 200 nm or less. desirable.

The proportion of fluorine atoms in the chain-type alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably, a perfluoroalkyl group in which all hydrogen atoms are replaced with fluorine atoms. to be.

In formula (b-2), V ¹⁰² and V ¹⁰³ are each independently a single bond, an alkylene group, or a fluorinated alkylene group, and the same ones as V ¹⁰¹ in formula (b-1) can be mentioned.

In formula (b-2), L ¹⁰¹ and L ¹⁰² are each independently a single bond or an oxygen atom.

・(B-3) Anion part of component

In formula (b-3), R ¹⁰⁶ to R ¹⁰⁸ are each independently a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, The same thing as R ¹⁰¹ in Formula (b-1) is mentioned, respectively.

L ¹⁰³ to L ¹⁰⁵ are each independently a single bond, -CO- or -SO ₂ -.

{Cation}

In formulas (b-1), (b-2) and (b-3), m is an integer of 1 or more, M'm ⁺ is an m-valent onium cation, and sulfonium cation and iodonium cation are preferred. Can be lifted. For example, it is particularly preferable that M'm ⁺ is an organic cation represented by the following general formulas (ca-1) to (ca-5), respectively.

[Formula 39]

[Wherein, R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² each independently represent an aryl group, an alkyl group or an alkenyl group which may have a substituent, and R ²⁰¹ to R ²⁰³ , R ²⁰⁶ to R ²⁰⁷ , R ²¹¹ R ²¹² may combine with each other to form a ring together with the sulfur atom in the formula. R ²⁰⁸ to R ²⁰⁹ each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ²¹⁰ is an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or -SO ₂ -which may have a substituent. It is a cyclic group containing, L ²⁰¹ represents -C(=O)- or -C(=O)-O-, Y ²⁰¹ each independently represents an arylene group, an alkylene group or an alkenylene group, and x is 1 Or 2, and W ²⁰¹ represents a (x + 1) valent linking group.]

Examples of the aryl group for R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² include an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group and a naphthyl group are preferable.

The alkyl group for R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² is a chain or cyclic alkyl group, and preferably has 1 to 30 carbon atoms.

The alkenyl groups in R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² preferably have 2 to 10 carbon atoms.

As the substituent which R ²⁰¹ to R ²⁰⁷ and R ²¹⁰ to R ²¹² may have, for example, an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, the following formula (ca-r-1) )-(Ca-r-8).

[Formula 40]

[In the formula, ^R'201 is each independently a hydrogen atom, a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.]

R 'cyclic group which may have a substituent group ^201, alkyl group of chain which may have a substituent, or an alkenyl chain which may have a substituent group, the same thing and R ¹⁰¹ in the above-described formula (b-1) In addition to the above, examples of the cyclic group which may have a substituent or the chain-like alkyl group which may have a substituent include the same acid-dissociable group represented by the formula (a1-r-2) described above.

When R ²⁰¹ to R ²⁰³ , R ²⁰⁶ to R ²⁰⁷ and R ²¹¹ to R ²¹² are bonded to each other to form a ring together with the sulfur atom in the formula, a hetero atom such as a sulfur atom, an oxygen atom, or a nitrogen atom, a carbonyl group, -SO-, -SO ₂ -, -SO ₃ -, -COO-, -CONH- or -N(R _N )- (The R _N is an alkyl group having 1 to 5 carbon atoms.) You may do it. As the ring to be formed, it is preferable that one ring containing a sulfur atom in the formula in the ring skeleton is a 3-10 membered ring, including a sulfur atom, and particularly preferably a 5-7 membered ring. Specific examples of the formed ring include, for example, thiophene ring, thiazole ring, benzothiophene ring, thiantrene ring, benzothiophene ring, dibenzothiophene ring, 9H-thioxanthene ring, and thioxanthone Rings, thiantrene rings, phenoxatine rings, tetrahydrothiophenium rings, tetrahydrothiopyranium rings, and the like.

R ²⁰⁸ to R ²⁰⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when forming an alkyl group, they may combine with each other to form a ring.

R ²¹⁰ is an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or a -SO ₂ -containing cyclic group which may have a substituent.

The alkyl group for R ²¹⁰ is a chain or cyclic alkyl group, and preferably has 1 to 30 carbon atoms.

The alkenyl group for R ²¹⁰ is preferably 2 to 10 carbon atoms.

In R ^210, -SO _2, which may have a substituent-containing cyclic group, the formula (a5-r-1) ~ -SO 2 each represent a (a5-r-4) - containing cyclic group and may include the same, among the "-SO ₂ - containing the cyclic group" is more preferably a group represented by as preferred, and the formula (a5-r-1).

In the formulas (ca-4) and (ca-5), Y ²⁰¹ each independently represents an arylene group, an alkylene group, or an alkenylene group.

The arylene group in Y ²⁰¹ includes a group in which one hydrogen atom is removed from the aryl group exemplified as the aromatic hydrocarbon group in R ¹⁰¹ in the formula (b-1) described above.

Examples of the alkylene group and the alkenylene group for Y ²⁰¹ include a group obtained by removing one hydrogen atom from the group exemplified as the chain alkyl group and the chain alkenyl group in R ¹⁰¹ in the formula (b-1) described above. .

In said Formula (ca-4) and Formula (ca-5), x is 1 or 2.

W ²⁰¹ is a (x + 1) value, that is, a bivalent or trivalent linking group.

As the divalent linking group in W ²⁰¹ , a divalent hydrocarbon group which may have a substituent is preferable, and a divalent hydrocarbon group which may have a substituent similar to Ya ²¹ in the general formula (a2-1) described above is exemplified. Can. The divalent linking group in W ²⁰¹ may be any of a straight chain, a branched chain, and a cyclic form, and is preferably cyclic. Especially, a group in which two carbonyl groups are combined at both ends of an arylene group is preferable. A phenylene group, a naphthylene group, etc. are mentioned as an arylene group, and a phenylene group is especially preferable.

Connection of the trivalent group is ²⁰¹ W, and ²⁰¹ W the group 1 to remove the hydrogen atom from the divalent linking group in, in addition to the divalent linking group, and the like which combines the divalent connecting group. As the trivalent linking group in W ²⁰¹ , a group in which two carbonyl groups are bonded to an arylene group is preferable.

As a preferable cation represented by said formula (ca-1), cation represented by following formula (ca-1-1)-(ca-1-129) specifically, is mentioned.

[Formula 41]

[Formula 42]

[Formula 43]

[In the formula, g1, g2, and g3 represent repeating numbers, g1 is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 20.]

[Formula 44]

[Formula 45]

[Formula 46]

[Formula 47]

[In the formula, R" ²⁰¹ is a hydrogen atom or a substituent, and the substituents are the same as those given as the substituents that R ²⁰¹ to R ²⁰⁷ and R ²¹⁰ to R ²¹² may have.]

[Formula 48]

[Formula 49]

As a preferable cation represented by said formula (ca-2), diphenyl iodonium cation, bis(4-tert-butylphenyl) iodium cation etc. are mentioned specifically,.

As a preferable cation represented by said formula (ca-3), cation represented by following formula (ca-3-1)-(ca-3-5) specifically, is mentioned.

[Formula 50]

As a preferable cation represented by said formula (ca-4), cation represented by following formula (ca-4-1)-(ca-4-2) specifically, is mentioned.

[Formula 51]

Moreover, as a cation represented by said formula (ca-5), the cation temperature represented by the following general formulas (ca-5-1)-(ca-5-3) is preferable.

[Formula 52]

Among these, the cation moiety [(M' ^m+ ) _1/m ] is preferably a cation represented by the general formula (ca-1), and more preferably a monophenyl type cation.

Moreover, as a preferable cation part [(M'm ⁺ ) _1/m ], the monophenyl type cation represented by the following general formula (ca-1-0) is mentioned.

[Formula 53]

[In formula, R ^b1 is an aryl group which may have a substituent. R ^b2 and R ^b3 are each independently an aliphatic hydrocarbon group. R ^b2 and R ^b3 may be bonded to each other to form a ring structure. L ^b1 , L ^b2 and L ^b3 are each independently a divalent linking group or a single bond.]

In the formula (ca-1-0), R ^b1 is an aryl group which may have a substituent, and in R ²⁰¹ to R ²⁰³ is the same as the aryl group which may have a substituent. That is, the aryl group in R ^b1 includes an aryl group having 6 to 20 carbon atoms, and a phenyl group and a naphthyl group are preferable. As a substituent which R ^b1 may have, for example, an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and the above formulas (ca-r-1) to (ca-r-8) Each group is mentioned.

In the formula (ca-1-0), R ^b2 and R ^b3 are each independently an aliphatic hydrocarbon group. The aliphatic hydrocarbon group for R ^b2 and R ^b3 may be a chain type, a cyclic type, or a chain or cyclic alkyl group or an alkenyl group.

The chain or cyclic alkyl group here is preferably 1 to 30 carbon atoms.

As an alkenyl group here, it is preferable that carbon number is 2-10.

R ^b2 and R ^b3 may be bonded to each other to form a ring structure. When combined with each other to form a ring together with the sulfur atom in the formula, a hetero atom such as a sulfur atom, an oxygen atom, or a nitrogen atom, or a carbonyl group, -SO-, -SO ₂ -, -SO ₃ -, -COO-,- You may combine via functional groups, such as CONH- or -N(R _N )- (The R _N is a C1-C5 alkyl group.). As the ring to be formed, it is preferable that one ring containing a sulfur atom in the formula in the ring skeleton is a 3-10 membered ring, including a sulfur atom, and particularly preferably a 5-7 membered ring. Specific examples of the formed ring include, for example, thiophene ring, thiazole ring, benzothiophene ring, thiantrene ring, benzothiophene ring, dibenzothiophene ring, 9H-thioxanthene ring, and thioxanthone Rings, thiantrene rings, phenoxatine rings, tetrahydrothiophenium rings, tetrahydrothiopyranium rings, and the like.

In the formula (ca-1-0), L ^b1 , L ^b2 and L ^b3 are each independently a divalent linking group or a single bond.

The divalent linking groups in L ^b1 , L ^b2 and L ^b3 are each independently -C(=O)-, -C(=O)-O-, -OC(=O)-, arylene group, An alkylene group or an alkenylene group etc. are mentioned.

The arylene group in L ^b1 , L ^b2 and L ^b3 includes a group in which one hydrogen atom is further removed from the aryl group exemplified as the aromatic hydrocarbon group for R ¹⁰¹ in the formula (b-1) described above. That is, a group in which two hydrogen atoms are removed from an aromatic ring (benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, or an aromatic heterocyclic ring in which some of the carbon atoms constituting these aromatic rings are substituted with hetero atoms) Can.

The alkylene group or alkenylene group in L ^b1 , L ^b2 and L ^b3 is a hydrogen atom from the groups exemplified as the chain alkyl group and the chain alkenyl group in R ¹⁰¹ in the formula (b-1) described above. The group which removed one more can be mentioned. That is, a group in which one hydrogen atom is further removed from a straight chain alkyl group having 1 to 20 carbon atoms, and a group in which one hydrogen atom is further removed from a branched chain alkyl group having 3 to 20 carbon atoms can be mentioned.

It is preferable that L ^b1 is a single bond, since the acid generation efficiency by exposure is higher.

(B) As a cation part of a component, cation represented by the following general formula (ca-1-01) or cation represented by general formula (ca-1-02) is more preferable. Especially preferably, it is a cation represented by general formula (ca-1-01).

[Formula 54]

[ ^Wherein , R ^b11 and R ^b12 are each independently an aryl group which may have a substituent. L ^b11 is -C(=O)- or -C(=O)-O-. R ^b121 and R ^b122 are each independently a hydrogen atom or a C1-C5 alkyl group. nb1 is an integer of 1-3. nb2 is an integer of 1-3.]

In the formula, R ^b11 and R ^b12 are the same as R ^b1 in the formula (ca-1-0), respectively. Especially, it is an unsubstituted aryl group preferably. As a preferable aryl group, a phenyl group and a naphthyl group are mentioned.

R ^b121 and R ^b122 are each a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom, a methyl group or an ethyl group, and more preferably a hydrogen atom.

nb1 is an integer of 1 to 3, preferably 1 or 2, more preferably 2.

nb2 is an integer of 1 to 3, preferably 1 or 2, more preferably 1.

As the cation represented by the general formula (ca-1-01), the cation represented by the formulas (ca-1-104) to (ca-1-129) are preferable, and among them, the formula (ca-1) -104) Cation represented by the formula (ca-1-105) (R" ²⁰¹ is a hydrogen atom) is more preferable.

The cation represented by the general formula (ca-1-02) is preferably a cation represented by the formula (ca-1-102) or a cation represented by the formula (ca-1-103).

(B) As a component, you may use the above-mentioned acid generator individually by 1 type, and may use it in combination of 2 or more type.

As a component (B) in this embodiment, the compound represented by the following general formula (b-1-0) is especially preferable.

[Formula 55]

[Wherein, R ^101, Y ^101, V ¹⁰¹ and R ¹⁰² is each is the same as the formula (b-1) of the R ^101, Y ^101, V ¹⁰¹ and R ^102. R ^b11 and is nb1, respectively, is the same as R nb1 and ^b11 in the above formula (ca-1-01).]

When the resist composition contains the component (B), the content of the component (B) is preferably 0.5 to 7 parts by mass, more preferably 1 to 4 parts by mass, and 1 to 3 parts by mass relative to 100 parts by mass of the component (A). Addition is more preferred.

(B) By making content of a component into the said range, pattern formation is fully implemented. Moreover, since each component of the resist composition is dissolved in an organic solvent, a uniform solution is easily obtained, and storage stability as a resist composition becomes favorable, which is preferable. Moreover, when content of (B) component is made into more than the lower limit of the said preferable range, the light transmittance of a resist film is easy to become high, and it becomes easy to achieve high sensitivity.

About the acid diffusion control agent component (D)

The resist composition of this embodiment is an acid diffusion control agent component (hereinafter referred to as "(D) component") in addition to (A) component or (A) component and (B) component. It may contain. The component (D) acts as a trap (acid diffusion control agent) for trapping the acid generated by exposure in the resist composition.

The component (D) may be a photodegradable base (D1) (which is hereinafter referred to as "(D1) component") that decomposes by exposure and loses acid diffusion controllability. Nitrogen-containing nitrogen that does not correspond to the component (D1) The organic compound (D2) (hereinafter referred to as "(D2) component") may be used.

About the (D1) component

By using the resist composition containing the component (D1), when forming a resist pattern, the contrast between the exposed portion and the unexposed portion of the resist film can be improved.

The component (D1) is not particularly limited as long as it is decomposed by exposure and loses acid diffusion control properties, and is a compound represented by the following general formula (d1-1) (hereinafter referred to as "(d1-1) component"), The compound represented by the following general formula (d1-2) (hereinafter referred to as the "(d1-2) component") and the compound represented by the following general formula (d1-3) (hereinafter referred to as the "(d1-3) component". ) Is preferably at least one compound selected from the group consisting of.

The components (d1-1) to (d1-3) do not act as a target because they decompose in the exposed portion of the resist film and lose acid diffusion control (basic), and act as a target in the unexposed portion. .

[Formula 56]

[Wherein, Rd ¹ to Rd ⁴ are cyclic groups which may have a substituent, chained alkyl groups which may have a substituent, or chained alkenyl groups which may have a substituent. However, in Rd ² in Formula (d1-2), the fluorine atom is not bound to the carbon atom adjacent to the S atom. Yd ¹ is a single bond or a divalent linking group. m is an integer of 1 or more, and M ^m+ are each independently an m-valent organic cation.]

{Component (d1-1)}

···Anion

In formula (d1-1), Rd ¹ is a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each of the above formula (b-1) The same thing as R ¹⁰¹ in the above can be mentioned.

Among these, Rd ¹ is preferably an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkyl group which may have a substituent. As the substituent which these groups may have, a hydroxyl group, an oxo group, an alkyl group, an aryl group, a fluorine atom, a fluorinated alkyl group, and lactone-containing cyclic groups represented by the general formulas (a2-r-1) to (a2-r-7), respectively. , Ether bonds, ester bonds, or combinations thereof. When an ether bond or an ester bond is included as a substituent, an alkylene group may be interposed, and as the substituent in this case, a linking group represented by the formulas (y-al-1) to (y-al-5), respectively, is preferable. Do.

The aromatic hydrocarbon group is more preferably a phenyl group or a naphthyl group.

The aliphatic cyclic group is more preferably a group obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

The chain-type alkyl group preferably has 1 to 10 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, etc. Straight-chain alkyl group; 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-methyl And branched chain alkyl groups such as pentyl group, 2-methylpentyl group, 3-methylpentyl group, and 4-methylpentyl group.

When the chain-like alkyl group is a fluorine atom or a fluorinated alkyl group having a fluorinated alkyl group as a substituent, the number of carbon atoms of the fluorinated alkyl group is preferably 1 to 11, more preferably 1 to 8 carbon atoms, and even more preferably 1 to 4 carbon atoms. . The fluorinated alkyl group may contain atoms other than the fluorine atom. As an atom other than a fluorine atom, an oxygen atom, a sulfur atom, a nitrogen atom, etc. are mentioned, for example.

As Rd ¹ , it is preferable that some or all of the hydrogen atoms constituting the linear alkyl group are fluorinated alkyl groups substituted with fluorine atoms, and all of the hydrogen atoms constituting the linear alkyl group are fluorinated alkyl groups substituted with fluorine atoms. It is particularly preferable to be a (linear perfluoroalkyl group).

Preferred specific examples of the anion portion of the component (d1-1) are shown below.

[Formula 57]

···Cation

In formula (d1-1), M ^m+ is an m-valent organic cation.

As the organic cation of M ^{m+, those similar to} the cations represented by the general formulas (ca-1) to (ca-5) are preferably mentioned, and the cation represented by the general formula (ca-1) is More preferably, cations represented by the formulas (ca-1-1) to (ca-1-129), respectively, are more preferable.

(d1-1) A component may be used individually by 1 type, or may be used in combination of 2 or more type.

{(d1-2) component}

···Anion

In formula (d1-2), Rd ² is a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and the formula (b-1) The same thing as R ¹⁰¹ in the above can be mentioned.

However, in Rd ² , the fluorine atom is not bound to the carbon atom adjacent to the S atom (not fluorine substituted). Thereby, the anion of the (d1-2) component becomes a moderately weak anion, and the ?? performance as the (D) component is improved.

As Rd ² , it is preferable that it is a chain alkyl group which may have a substituent or an aliphatic cyclic group which may have a substituent. The chain alkyl group is preferably 1 to 10 carbon atoms, and more preferably 3 to 10 carbon atoms. Examples of the aliphatic cyclic group include a group obtained by removing one or more hydrogen atoms from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane and the like (may have a substituent); It is more preferable that the group is one or more hydrogen atoms removed from a camper or the like.

The hydrocarbon group of Rd ² may have a substituent, and as the substituent, the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, chain alkyl group) in Rd ¹ of the formula (d1-1) may have And the same.

Preferred specific examples of the anion portion of the (d1-2) component are shown below.

[Formula 58]

···Cation

In formula (d1-2), M ^m+ is an m-valent organic cation, and is the same as M ^m+ in formula (d1-1).

(d1-2) A component may be used individually by 1 type, and may be used in combination of 2 or more type.

{(d1-3) component}

···Anion

In formula (d1-3), Rd ³ is a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and in the formula (b-1) The same thing as R ^{101 is mentioned,} and it is preferable that it is a cyclic group containing a fluorine atom, a chain alkyl group, or a chain alkenyl group. Especially, a fluorinated alkyl group is preferable, and the same thing as the fluorinated alkyl group of Rd ¹ is more preferable.

In formula (d1-3), Rd ⁴ is a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and the formula (b-1) The same thing as R ¹⁰¹ in the above can be mentioned.

Especially, it is preferable that it is an alkyl group, an alkoxy group, an alkenyl group, and a cyclic group which may have a substituent.

The alkyl group for Rd ⁴ is preferably a linear or branched chain alkyl group having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. A part of the hydrogen atom of the alkyl group of Rd ⁴ may be substituted with a hydroxyl group, a cyano group, or the like.

The alkoxy group for Rd ⁴ is preferably an alkoxy group having 1 to 5 carbon atoms, and specifically, an alkoxy group having 1 to 5 carbon atoms, specifically, a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, and an n- And a butoxy group and a tert-butoxy group. Especially, a methoxy group and an ethoxy group are preferable.

The alkenyl group in Rd ⁴ includes the same ones as R ¹⁰¹ in the formula (b-1), and vinyl groups, propenyl groups (allyl groups), 1-methylpropenyl groups, and 2-methylpropenyl groups are preferred. . These groups may also have, as substituents, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms.

The cyclic group in Rd ⁴ includes the same ones as R ¹⁰¹ in the formula (b-1), and cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, and tetracyclo An alicyclic group in which one or more hydrogen atoms are removed from cycloalkanes such as dodecane or an aromatic group such as a phenyl group or a naphthyl group is preferable. When Rd ⁴ is an alicyclic group, the resist composition is favorably dissolved in an organic solvent, whereby lithography properties are improved. Also, Rd is ⁴ when an aromatic group, and that a resist composition excellent in light-absorbing efficiency, it is excellent in sensitivity and the lithographic properties.

In formula (d1-3), Yd ¹ is a single bond or a divalent linking group.

Group connection divalent in Yd ¹ is not particularly limited, there may be mentioned a divalent hydrocarbon group which may have a substituent (the aliphatic hydrocarbon group, an aromatic hydrocarbon group), a divalent connecting group, such as containing a hetero atom. Among these, in the description of the divalent linking group in Ya ²¹ in the formula (a2-1), the same may be mentioned as the divalent hydrocarbon group which may have a substituent, or a divalent linking group containing a hetero atom.

Yd ¹ is preferably a carbonyl group, an ester bond, an amide bond, an alkylene group, or a combination thereof. The alkylene group is more preferably a straight chain or branched chain alkylene group, and more preferably a methylene group or an ethylene group.

Preferred specific examples of the anion portion of the (d1-3) component are shown below.

[Formula 59]

[Formula 60]

···Cation

In Formula (d1-3), M ^m+ is an m-valent organic cation, and is the same as M ^m+ in Formula (d1-1).

(d1-3) A component may be used individually by 1 type, or may be used in combination of 2 or more type.

As the component (D1), any one of the components (d1-1) to (d1-3) may be used, or two or more of them may be used in combination.

When the resist composition contains the component (D1), the content of the component (D1) is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, based on 100 parts by mass of the component (A), 1 It is more preferable that it is 8 mass parts.

When the content of the component (D1) is greater than or equal to a preferable lower limit, particularly good lithography properties and resist pattern shapes are likely to be obtained. On the other hand, if it is less than or equal to the upper limit, sensitivity can be maintained satisfactorily and throughput is excellent.

(D1) Preparation method of ingredients:

The manufacturing method of the said (d1-1) component and (d1-2) component is not specifically limited, It can be manufactured by a well-known method.

Moreover, the manufacturing method of (d1-3) component is not specifically limited, For example, it manufactures by carrying out similarly to the method described in US2012-0149916.

・About (D2) ingredient

As the acid diffusion control agent component, a nitrogen-containing organic compound component (hereinafter referred to as "(D2) component") that does not correspond to the above (D1) component may be contained.

(D2) As a component, it acts as an acid-diffusion control agent, and if it does not correspond to the (D1) component, it will not specifically limit, You may use arbitrarily from a well-known thing. Among them, aliphatic amines are preferred, and among them, secondary aliphatic amines and tertiary aliphatic amines are more preferable.

The aliphatic amine is an amine having at least one aliphatic group, and the aliphatic group preferably has 1 to 12 carbon atoms.

Examples of the aliphatic amine include amines (alkylamines or alkylalcoholamines) or cyclic amines in which at least one of the hydrogen atoms of ammonia NH ₃ is substituted with an alkyl group or a hydroxyalkyl group having 12 or less carbon atoms.

Specific examples of the alkylamine and alkylalcoholamine include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; Dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; Trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri trialkylamines such as -n-nonylamine, tri-n-decylamine, and tri-n-dodecylamine; And alkyl alcohol amines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine. Among these, trialkylamines having 5 to 10 carbon atoms are more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

As a cyclic amine, the heterocyclic compound containing a nitrogen atom as a hetero atom is mentioned, for example. The heterocyclic compound may be a monocyclic (aliphatic monocyclic amine) or a polycyclic (aliphatic polycyclic amine).

Specific examples of the aliphatic monocyclic amines include piperidine and piperazine.

The aliphatic polycyclic amine preferably has 6 to 10 carbon atoms, and specifically, 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0] And -7-undecene, hexamethylenetetramine, and 1,4-diazabicyclo[2.2.2]octane.

As other aliphatic amines, tris(2-methoxymethoxyethyl)amine, tris{2-(2-methoxyethoxy)ethyl}amine, tris{2-(2-methoxyethoxymethoxy)ethyl} Amine, tris{2-(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine, tris{2-(1-ethoxypropoxy)ethyl}amine, Tris[2-{2-(2-hydroxyethoxy)ethoxy}ethyl]amine, triethanolamine triacetate, and the like, and triethanolamine triacetate is preferred.

Moreover, you may use an aromatic amine as (D2) component.

As aromatic amine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxycarbonylpyrrolidine, etc. Can be heard.

(D2) A component may be used individually and may be used in combination of 2 or more type.

When the resist composition contains the component (D2), the component (D2) is usually used in the range of 0.01 to 5 parts by mass relative to 100 parts by mass of the component (A). By setting it as the said range, the shape of a resist pattern, delayed time-lapse stability, etc. improve.

-For at least one compound (E) selected from the group consisting of organic carboxylic acids and phosphorus oxo acids and derivatives thereof

In the resist composition of the present embodiment, for the purpose of preventing deterioration of sensitivity, improving resist pattern shape, delayed time-lapse stability, etc., a group consisting of organic carboxylic acid and oxo acid of phosphorus and derivatives thereof as an optional component At least one compound (E) selected from (hereinafter referred to as "(E) component") 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 preferred.

As the oxo acid of phosphorus, phosphoric acid, phosphonic acid, phosphinic acid, etc. are mentioned, and among these, phosphonic acid is particularly preferable.

Examples of the derivative of oxo acid of phosphorus include, for example, an ester in which the hydrogen atom of the oxo acid is substituted with a hydrocarbon group, and examples of the hydrocarbon group include an alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 15 carbon atoms, and the like. Can be heard.

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.

As a derivative of phosphinic acid, a phosphinic acid ester, phenylphosphinic acid, etc. are mentioned.

(E) As a component, you may use individually by 1 type and may use 2 or more types together.

When the resist composition contains the component (E), the component (E) is usually used in a range of 0.01 to 5 parts by mass relative to 100 parts by mass of the component (A).

About the fluorine additive component (F)

The resist composition of the present embodiment may contain a fluorine additive component (hereinafter referred to as "(F) component") in order to impart water repellency to the resist film.

As the component (F), for example, Japanese Patent Application Publication No. 2010-002870, Japanese Patent Application Publication No. 2010-032994, Japanese Patent Application Publication No. 2010-277043, Japanese Patent Application Publication No. 2011-13569, Japanese Patent Application The fluorine-containing polymer compound described in Publication No. 2011-128226 can be used.

More specifically, as the component (F), a polymer having a structural unit (f1) represented by the following formula (f1-1) is exemplified. As said polymer, Polymer (homopolymer) which consists only of the structural unit (f1) represented by following formula (f1-1); A copolymer of a structural unit (a1) and an structural unit (f1) containing an acid-decomposable group whose polarity increases by the action of an acid; The structural unit (f1), the structural unit derived from acrylic acid or methacrylic acid, and the copolymer of the structural unit (a1) are preferred. Here, as a preferable thing of the said structural unit (a1) copolymerized with the structural unit (f1), For example, the structural unit derived from 1-ethyl-1-cyclooctyl (meth)acrylate, 1-methyl-1 -The structural unit derived from adamantyl (meth)acrylate is mentioned.

[Formula 61]

[Wherein, R is as defined above, Rf ¹⁰² and Rf ¹⁰³ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and Rf ¹⁰² and Rf ¹⁰³ are the same It may be different. nf ¹ is an integer from 1 to 5, and Rf ¹⁰¹ is an organic group containing a fluorine atom.]

In formula (f1-1), R bonded to the carbon atom at the α position is the same as described above. As R, a hydrogen atom or a methyl group is preferable.

In the formula (f1-1), examples of the halogen atom for Rf ¹⁰² and Rf ¹⁰³ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. Examples of the alkyl group having 1 to 5 carbon atoms for Rf ¹⁰² and Rf ^{103 include} the same as the alkyl group having 1 to 5 carbon atoms for R, and a methyl group or an ethyl group is preferable. Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms of Rf ¹⁰² and Rf ¹⁰³ include groups in which part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms.

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. Especially, as Rf ¹⁰² and Rf ¹⁰³ , a hydrogen atom, a fluorine atom, or a C1-C5 alkyl group is preferable, and a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group is preferable.

In formula (f1-1), nf ¹ is an integer of 1 to 5, preferably an integer of 1 to 3, more preferably 1 or 2.

In formula (f1-1), Rf ¹⁰¹ is an organic group containing a fluorine atom, and preferably a hydrocarbon group containing a fluorine atom.

The hydrocarbon group containing a fluorine atom may be any of a straight chain, branched chain, or cyclic, preferably 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and 1 to 10 carbon atoms. Especially preferred.

Moreover, it is preferable that 25% or more of the hydrogen atom in the said hydrocarbon group is fluorinated, it is more preferable that 50% or more is fluorinated, and 60% or more of the hydrocarbon group containing a fluorine atom is fluorinated, It is particularly preferable from the viewpoint of increasing the hydrophobicity of the resist film during immersion exposure.

Among them, Rf ¹⁰¹ is more preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, a trifluoromethyl group, -CH ₂ -CF ₃ , -CH ₂ -CF ₂ -CF ₃ , -CH(CF ₃ ) ₂ ,- CH ₂ -CH ₂ -CF ₃ , -CH ₂ -CH ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₃ are particularly preferred.

The weight average molecular weight (Mw) of the component (F) (based on polystyrene conversion by gel permeation chromatography) is preferably 1000 to 50000, more preferably 5000 to 40000, and most preferably 10000 to 30000. If it is less than or equal to the upper limit of this range, sufficient solubility in a solvent for resist is used for use as a resist, and if it is equal to or greater than the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.

The dispersion degree (Mw/Mn) of the component (F) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5.

(F) As a component, you may use individually by 1 type and may use 2 or more types together.

When the resist composition contains the component (F), the component (F) is usually used in a proportion of 0.5 to 10 parts by mass relative to 100 parts by mass of the component (A).

・About organic solvent component (S)

The resist composition of this embodiment can be produced by dissolving the resist material in an organic solvent component (hereinafter sometimes referred to as "(S) component").

As the component (S), any component to be used may be used as long as it dissolves each component to be a uniform solution, and any of those known as a solvent for a chemically amplified resist composition can be appropriately selected and used.

For example, as (S) component, lactones, such as γ-butyrolactone; Ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; 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 of the polyhydric alcohols or compounds having the ester bond, Derivatives of polyhydric alcohols such as monoalkyl ethers such as monopropyl ether and monobutyl ether or compounds having ether bonds such as monophenyl ether [among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) is preferable]; Cyclic ethers such as dioxane, esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate and ethyl ethoxypropionate; Anisole, ethylbenzyl ether, cresylmethyl ether, diphenyl ether, dibenzyl ether, phenitol, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cement, mesitylene, etc. And aromatic organic solvents, dimethyl sulfoxide (DMSO), and the like.

(S) A component may be used individually and may be used as two or more types of mixed solvents.

Among them, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferred.

Moreover, a mixed solvent in which PGMEA and a polar solvent are mixed is also preferable. The compounding ratio (mass ratio) may be appropriately determined in consideration of compatibility of PGMEA and a polar solvent, but is preferably in the range of 1:9 to 9:1, more preferably 2:8 to 8:2. desirable.

More specifically, when blending EL or cyclohexanone as a polar solvent, the mass ratio of PGMEA:EL or cyclohexanone 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 is preferably 1:9-9:1, More preferably 2:8-8:2, More preferably 3:7- It is 7:3. Also, a mixed solvent of PGMEA, PGME and cyclohexanone is preferred.

Moreover, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, as the mixing ratio, the mass ratio of the former and the latter is preferably 70:30 to 95:5.

The amount of the (S) component is not particularly limited, and is appropriately set depending on the thickness of the coating film at a concentration applicable to a substrate or the like. In general, the (S) component is used so that the solid content concentration of the resist composition is in the range of 20 to 55 mass%, preferably 30 to 45 mass%.

In the resist composition of the present embodiment, additionally miscible additives, for example, additional resins for improving the performance of the resist film, surfactants (for example, fluorine-based surfactants, etc.), dissolution inhibitors, Plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be appropriately added.

The method for forming a resist pattern according to the present embodiment described above is a method useful for forming a resist film having a high film thickness of 7 µm or more, and is performed using a specific resist composition.

By using a specific resist composition, that is, a resist composition containing a resin component (A1) having a structural unit (a10), a structural unit (a4), and a structural unit (a1), light transmittance of the resist film having a high film thickness is increased. Thereby, even when a resist film of a high film thickness having a film thickness of 7 µm or more is formed, high sensitivity and resolution are improved, and a resist pattern having a good shape can be formed.

Moreover, according to such a resist pattern formation method, the solubility to a developer is improved by using the specific resist composition. Thereby, generation|occurrence|production of defect can be suppressed and stability of a pattern dimension can be raised. Further, according to such a resist pattern forming method, sufficient etching resistance is maintained.

Such a resist pattern forming method is useful for manufacturing a three-dimensional structural device, and is a preferred method for applications (overlapping, etc.) for processing a multi-stage staircase structure. By applying the method for forming a resist pattern of the present embodiment, it is possible to realize a high-precision stacking of memory films (three-dimensionalization, production of a large capacity memory).

Example

Hereinafter, the present invention will be described in more detail by examples, but the present invention is not limited by these examples.

<Preparation of resist composition>

Each component shown in Table 1 was mixed and dissolved to prepare resist compositions (1) to (6) (all solid content concentrations of 40 mass%), respectively.

In Table 1, each symbol has the following meaning. The value in [] is the compounding quantity (part by mass).

(A)-1: A polymer compound represented by the following formula (A1)-1. The weight average molecular weight (Mw) of standard polystyrene conversion calculated by GPC measurement is 10000, and molecular weight dispersion degree (Mw/Mn) is 2.5. ^The copolymerization composition ratio (ratio of each structural unit in the structural formula (molar ratio)) obtained by ¹³ C-NMR is a structural unit (a101)/a structural unit (a41)/a structural unit (a11) = 50/35/15.

(A)-2: A polymer compound represented by the following formula (A1)-1. The weight average molecular weight (Mw) of standard polystyrene conversion calculated by GPC measurement is 10000, and molecular weight dispersion degree (Mw/Mn) is 2.5. ^The copolymerization composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) obtained by ¹³ C-NMR is the structural unit (a101)/structural unit (a41)/structural unit (a11) = 65/20/15.

(A)-3: A polymer compound represented by the following formula (A1)-1. The weight average molecular weight (Mw) of standard polystyrene conversion calculated by GPC measurement is 10000, and molecular weight dispersion degree (Mw/Mn) is 2.5. ^The copolymerization composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) obtained by ¹³ C-NMR is the structural unit (a101)/structural unit (a41)/structural unit (a11) = 70/15/15.

(A)-4: A polymer compound represented by the following formula (A1)-1. The weight average molecular weight (Mw) of standard polystyrene conversion calculated by GPC measurement is 10000, and molecular weight dispersion degree (Mw/Mn) is 2.5. ^The copolymerization composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) obtained by ¹³ C-NMR is the structural unit (a101)/structural unit (a41)/structural unit (a11) = 40/45/15.

(A)-5: A polymer compound represented by the following formula (A1)-1. The weight average molecular weight (Mw) of standard polystyrene conversion calculated by GPC measurement is 10000, and molecular weight dispersion degree (Mw/Mn) is 2.5. ^The copolymerization composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) obtained by ¹³ C-NMR is the structural unit (a101)/structural unit (a41)/structural unit (a11) = 80/5/15.

(A)-6: A polymer compound represented by the following formula (A2)-1. The weight average molecular weight (Mw) of standard polystyrene conversion calculated by GPC measurement is 10000, and molecular weight dispersion degree (Mw/Mn) is 2.5. ^The copolymerization composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) obtained by ¹³ C-NMR is the structural unit (a101)/structural unit (st1)/structural unit (a12) = 65/20/15.

[Formula 62]

(B)-1: An acid generator comprising the compound represented by the following formula (B)-1.

[Formula 63]

(D)-1: Tri-n-pentylamine.

(E)-1: Phenylphosphonic acid.

(Add)-1: Fluorine surfactant, trade name "R-40" manufactured by DIC Corporation.

(S)-1: Propylene glycol monomethyl ether acetate/propylene glycol monomethyl ether = 5/5 (mass ratio).

<Formation of resist pattern (I)>

(Examples 1-3)

Process (i):

On the 8-inch silicon wafer, the resist compositions (1) to (3) were respectively applied using a coater, and subjected to pre-baking (PAB) treatment at 130°C for 90 seconds on a hot plate, followed by drying. A resist film having a film thickness of 15 µm was formed.

Process (ii):

Next, for the resist film, KrF excimer laser (248 nm) was masked (6% halftone) by a KrF exposure apparatus NSR-S203B (manufactured by Nikon; NA (number of apertures) = 0.68, σ = 0.40). ).

Subsequently, heating (PEB) treatment was performed at 110° C. for 90 seconds after exposure.

Process (iii):

Subsequently, a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-3" (trade name, manufactured by Tokyo Oka Industry Co., Ltd.) was used as the developer, and alkali development was carried out at 23°C for 60 seconds.

Thereafter, water was rinsed for 30 seconds using pure water, and shaken to dry.

(Comparative Example 1)

A resist pattern was formed in the same manner as in Examples 1 to 3, except that the resist composition (6) was used.

As a result of the formation (I) of the above-described resist pattern, in any of the examples, an isolated line pattern (hereinafter referred to as an “IS pattern”) having a space width of 5 μm was formed in the resist film.

[Sensitivity]

The optimum exposure dose Eop (mJ/cm 2) when the IS pattern of the target size was formed by the above-described formation of the resist pattern (I) was determined and used as sensitivity. This was shown in Table 2 as "Eop (mJ/cm2)".

[Shape of resist pattern]

The shape of the IS pattern formed by the above-described formation of the resist pattern (I) was observed by a lengthwise SEM (scanning electron microscope, acceleration voltage 800 V, product name: SU-8000, manufactured by Hitachi High-Technologies), and the following According to the evaluation criteria, the evaluation results are shown in Table 2 as "shape".

Evaluation criteria A: Tapered shape B: Top-round phase

From the results shown in Table 2, according to the resist pattern forming methods of Examples 1 to 3, even when a resist film having a film thickness of 15 µm was formed, it exhibited high sensitivity and was able to form a pattern of good shape. Is admitted.

On the other hand, in the resist pattern forming method of Comparative Example 1, the sensitivity was low and the shape was also poor.

<Formation of resist pattern (II)>

(Examples 4 to 8)

Process (i):

By coating the resist compositions (1) to (5) on an 8-inch silicon wafer, respectively, using a coater, pre-baking (PAB) treatment at 130° C. for 90 seconds on a hot plate, and drying, A resist film having a film thickness of 15 µm was formed.

Process (ii):

Next, for the resist film, KrF excimer laser (248 nm) was masked (6% halftone) by a KrF exposure apparatus NSR-S203B (manufactured by Nikon; NA (number of apertures) = 0.68, σ = 0.40). ).

Subsequently, heating (PEB) treatment was performed at 110° C. for 90 seconds after exposure.

Process (iii):

Subsequently, a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-3" (trade name, manufactured by Tokyo Oka Industry Co., Ltd.) was used as the developer, and alkali development was carried out at 23°C for 60 seconds.

Thereafter, water was rinsed for 30 seconds using pure water, and shaken to dry.

As a result of the formation (II) of the above-described resist pattern, in any of the examples, an isolated line pattern (hereinafter referred to as an “IS pattern”) having a space width of 3 μm was formed in the resist film.

[Defect (defect function)]

About the IS pattern formed by the formation (II) of the above-described resist pattern, the total number of defects (total number of defects) in the wafer was measured using a surface defect observation device (manufactured by KLA Tencor, product name: KLA2371). .

The wafers provided for these measurements were set to 2 sheets for each example, and the average number of defects (total number of defects) in the wafer was adopted. Then, according to the following evaluation criteria, the evaluation results are shown in Table 3 as "Defect".

Evaluation standard

A: 200 defects or less

B: More than 200 defects and less than 300 defects

C: 300 defects or more

[Dimension Uniformity in Wafer Surface (CDU)]

For the IS pattern formed by the above-described formation of the resist pattern (II), the IS pattern is measured by SEM (scanning electron microscope, acceleration voltage 300 V, trade name: S-9380, manufactured by Hitachi High-Technologies Corporation). (7×15 shot) was observed from above, and the space width of the IS pattern (38 points in the shot) was measured. Three batches (3σ) of standard deviation (σ) calculated from the measurement results were determined. The smaller the value of 3σ obtained in this way means that the uniformity of the dimension (CD) of the space width formed in the resist film is high.

Then, according to the following evaluation criteria, the evaluation results are shown in Table 3 as "CDU".

Evaluation standard

A: The value of 3σ is 60 nm or less

B: The value of 3σ is greater than 60 nm and less than 70 nm

C: The value of 3σ is 70 nm or more

From the results shown in Table 3, according to the resist pattern forming methods of Examples 4 to 8, it was recognized that the occurrence of defects was reduced and the dimension (CD) uniformity was also high. In particular, it is recognized that these effects are higher when the resist compositions (1), (2), and (3) are used (especially when the resist composition (2) is used).

The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other changes to the configuration are possible without departing from the spirit of the present invention. The present invention is not limited by the above description, but only by the scope of the attached claims.

Claims (6)

Step (i) of forming a resist film having a thickness of 7 µm or more using a resist composition on the support, step (ii) of exposing the resist film, and step (iii) of developing the resist film after exposure to form a resist pattern As a method of forming a resist pattern,
The resist composition generates an acid by exposure, and the solubility in a developer is changed by the action of an acid, and the structural unit (a10) represented by the following general formula (a10-1) and an acid non-aliphatic aliphatic ring A method for forming a resist pattern comprising a resin component (A1) having a structural unit (a4) containing a mold group and a structural unit (a1) containing an acid decomposable group whose polarity increases by the action of an acid.

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Ya ^x1 is a single bond or a divalent linking group. Wa ^x1 is a (n _ax1 + 1) valent aromatic hydrocarbon group. n _ax1 is an integer of 1-3.] According to claim 1,
The acid decomposable group in the said structural unit (a1) contains an aliphatic cyclic group, The resist pattern formation method. According to claim 2,
The acid decomposable group in the structural unit (a1) includes an acid dissociable group represented by the following general formula (a1-r2-11).

[In the formula, Ra ^'10 is a hydrocarbon group of 1 to 10 carbon atoms. Ra" ¹¹ is a group forming a monocyclic aliphatic cyclic group together with the carbon atom to which Ra' ¹⁰ is bonded. * is a bonding hand.] The method according to any one of claims 1 to 3,
The content ratio of the said structural unit (a10) is 45-75 mol% with respect to the total structural unit (100 mol%) which comprises the said resin component (A1), The resist pattern formation method. The method according to any one of claims 1 to 4,
The content ratio of the said structural unit (a1) is 5-20 mol% with respect to the total structural unit (100 mol%) which comprises the said resin component (A1), The resist pattern formation method. The method according to any one of claims 1 to 5,
In the said step (ii), the resist film is irradiated with KrF excimer laser light, The resist pattern formation method.