JP2011215429A - Radiation-sensitive resin composition and polymer used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation sensitive resin composition nearly free from development defect and to provide a polymer used therefor.SOLUTION: The radiation sensitive resin composition contains a polymer (A)having a carbonyl group on at least one terminal of a molecular chain, having weight average molecular weight in terms of polystyrene by gel permeation chromatography of ≥11,000 and decomposed by action of an acid and increasing solubility in an alkali developer and a radiation-sensitive acid generator (B).

Description

The present invention relates to a radiation-sensitive resin composition for obtaining a positive photoresist film for microfabrication such as a semiconductor element and a polymer used therefor.

  The chemically amplified radiation-sensitive resin composition generates an acid in an exposed portion by irradiation with far ultraviolet rays or electron beams typified by a KrF excimer laser or an ArF excimer laser, and is exposed by a chemical reaction using this acid as a catalyst. It is a composition that causes a difference in the dissolution rate of the part and the unexposed part in the developer to form a resist pattern on the substrate.

  For example, when a KrF excimer laser (wavelength 248 nm) is used as a light source, a polymer having a basic skeleton of poly (hydroxystyrene) (hereinafter sometimes referred to as “PHS”) that has low absorption in the 248 nm region. A chemically amplified radiation-sensitive resin composition containing as a constituent is used. According to this composition, high sensitivity, high resolution, and good pattern formation can be realized.

  However, when a shorter wavelength light source, for example, an ArF excimer laser (wavelength 193 nm) is used as a light source for the purpose of further microfabrication, an aromatic compound such as PHS having a large absorption in the 193 nm region should be used. There was a problem that was difficult.

  Therefore, as a lithographic material using an ArF excimer laser as a light source, a resin composition containing a polymer having an alicyclic hydrocarbon that does not have large absorption in the 193 nm region in its skeleton is used.

  As the radiation sensitive resin composition as described above, for example, a radiation sensitive resin composition containing a polymer having an adamantane skeleton, a norbornane skeleton or a cyclohexane skeleton in its repeating unit is disclosed ( (See Patent Documents 1 to 4).

JP 2003-277446 A JP 2002-303978 A JP 2002-372784 A Japanese Patent Laid-Open No. 2004-126013

  The radiation-sensitive resin composition shown in Patent Documents 1 to 4 has an alkali-insoluble or hardly-soluble alkali-soluble polymer that becomes alkali-soluble by the action of an acid and a lactone skeleton in its repeating unit. It has been found that the resolution performance is dramatically improved. However, there is a problem that development defects still occur, and further improvement is required.

  The present invention has been made in view of such problems of the prior art, and provides a radiation-sensitive resin composition with few development defects.

  The present invention provides the following radiation-sensitive resin composition and a polymer used therefor.

[1] (A) A carbonyl group at least at one end of the molecular chain, and a polystyrene-reduced weight average molecular weight by gel permeation chromatography of 11,000 or more, which is decomposed by the action of an acid and is soluble in an alkali developer. Containing a polymer (hereinafter also referred to as “polymer (A)”) and (B) a radiation-sensitive acid generator (hereinafter also referred to as “acid generator (B)”). A radiation-sensitive resin composition.
[2] The radiation sensitive resin composition according to [1], wherein the polymer (A) further includes at least one selected from a repeating unit having a lactone structure and a repeating unit having a cyclic carbonate structure.
[3] It has a carbonyl group at at least one end of the molecular chain and has a polystyrene-equivalent weight average molecular weight of 11,000 or more by gel permeation chromatography, which is decomposed by the action of an acid and increases the solubility in an alkali developer. Polymer.

According to the present invention, a radiation-sensitive resin composition with few development defects and a polymer used therefor can be provided.

  Hereinafter, although the form for implementing this invention is demonstrated, this invention is not limited to the following embodiment.

<Radiation sensitive resin composition>
The radiation-sensitive resin composition of the present invention has a carbonyl group at least at one end of a molecular chain (main chain), and has a polystyrene-reduced weight average molecular weight of 11,000 or more by gel permeation chromatography. The polymer (A) which decomposes | disassembles and the solubility with respect to an alkali developing solution increases, and an acid generator (B) are contained.
The polymer (A) is a polymer that exhibits alkali insolubility or alkali insolubility before the action of an acid, and is readily soluble in alkali by dissociation of an acid dissociable group by the action of an acid. It is thought that the radiation sensitive resin composition with few development defects can be obtained because the polymer (A) contains a carbonyl group at the end of the molecular chain and is a high molecular weight product.

As used herein, “alkali-insoluble or alkali-insoluble” refers to a resist film under the alkali development conditions employed when a resist pattern is formed from a resist film formed from the radiation-sensitive resin composition. In the case where a film using only the polymer of the component [A] is developed instead of the above, it means that 50% or more of the initial film thickness of the film remains after development. The “radiation” of the “radiation-sensitive resin composition” and “radiation-sensitive acid generator” in the present specification is a concept including visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams, and the like. is there.
Hereinafter, each component will be described in detail.

Polymer (A):
The polymer (A) used in the radiation-sensitive resin composition of the present invention is the polymer of the present invention and has a carbonyl group at least at one end of the molecular chain. The “molecular chain” referred to here indicates a polymer main chain. That is, the polymer (A) has a structure represented by the following general formula (a), for example. The main chain of the polymer (A) may be linear or branched.

(In the general formula (a), A ^1, A ² and A ⁿ represents a respective structural units in the polymer, X and Y represents a monovalent organic group. However, at least one of X and Y, fat (It is an organic group having a cyclic hydrocarbon group.)

A polymer having a carbonyl group at the end of the polymer can be obtained, for example, by any of the following methods.
(1) A method of polymerizing using a radical polymerization initiator having a carbonyl group.
(2) A method of polymerizing in the presence of a chain transfer agent having a carbonyl group.
(3) A method using a radical terminator having a carbonyl group.
(4) A method of polymerizing using an anionic polymerization initiator having a carboxylic acid ester group, terminating the polymerization with an alcohol, and hydrolyzing the resulting polymer.
(5) A method in which, after anionic polymerization, polymerization is terminated using a polymerization terminator having a carboxylic acid ester group or carbon dioxide, and the resulting polymer is hydrolyzed.
(6) A method of hydrolyzing the polymer obtained after group transfer polymerization using an enolate initiator in which two hydroxyl groups are protected with a trialkylsilyl group.
(7) A method of introducing a carboxyl group by a polymer reaction after obtaining a polymer having a hydroxyl group, an amino group or the like at the polymer terminal.
Of these, the method (1) or (2) is particularly preferably used.

  Examples of the radical polymerization initiator include compounds represented by the following formulas (a1) to (a3).

  Examples of the chain transfer agent include mercaptoacetic acid, mercaptopropionic acid, and thiosalicylic acid.

  Examples of other radical polymerization initiators that can be used for the polymerization of the polymer (A) of the present invention include known ones. Specifically, 2,2′-azobis (4-methoxy -2,4-dimethylvaleronitrile), 2,2'-azobis (2-cyclopropylpropionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), and the like. These can be used alone or in combination of two or more. These radical polymerization initiators can be used in combination with the above-described radical polymerization initiator having a carbonyl group, and can be used as a radical polymerization initiator when the above-described chain transfer agent is used.

  As a method for synthesizing the polymer (A), it can be synthesized according to a conventional method of radical polymerization. For example, (1) a method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction; (2) a solution containing the monomer and a radical A method in which a solution containing an initiator is dropped into a reaction solvent or a solution containing a monomer separately to cause a polymerization reaction; (3) a plurality of types of solutions containing each monomer, and radical initiation A method in which a solution containing an agent is separately added to a reaction solvent or a solution containing a monomer to cause a polymerization reaction; (4) a solution containing a monomer, a radical initiator, and a chain transfer agent is reacted. It is preferable to synthesize by a method such as a method of dropping a solvent or a monomer-containing solution to cause a polymerization reaction.

  In addition, when the monomer solution is dropped and reacted with respect to the monomer solution, the monomer amount in the dropped monomer solution is 30 mol with respect to the total amount of monomers used for polymerization. % Or more, more preferably 50 mol% or more, and particularly preferably 70 mol% or more.

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species. Usually, it is 30-180 degreeC, 40-160 degreeC is preferable and 50-140 degreeC is still more preferable. Although dripping time changes with conditions, such as reaction temperature, the kind of initiator, and the monomer made to react, it is 30 minutes-8 hours normally, 45 minutes-6 hours are preferable, and 1-5 hours are still more preferable. Further, the total reaction time including the dropping time varies depending on the conditions as well as the dropping time, but is usually 30 minutes to 8 hours, preferably 45 minutes to 7 hours, and more preferably 1 to 6 hours.

The amount of radical initiator used is preferably 0.1 mol% to 30 mol% or less, more preferably 0.1 mol% to 25 mol% or less, particularly preferably 0.1 mol%, based on the total amount of monomers. ˜20 mol% or less. The amount of the chain transfer agent used is preferably 70 mol% or less, particularly preferably 50% or less, based on the initiator amount. By setting it as such a range, the polystyrene conversion weight average molecular weight (henceforth "Mw") by the gel permeation chromatography (GPC) of a polymer will be 11,000 or more. If the Mw of the polymer is less than 11,000, the effect of reducing development defects may not be obtained. Mw is more preferably 11,000 to 200,000, and particularly preferably 11,000 to 50,000.

  As a polymerization solvent, a solvent other than a solvent that inhibits polymerization (nitrobenzene having a polymerization inhibiting effect, mercapto compound having a chain transfer effect, or the like) and a solvent that can dissolve the monomer may be used. it can. Examples thereof include alcohols, ethers, ketones, amides, esters / lactones, nitriles, and mixed solvents thereof. These solvents can be used alone or in admixture of two or more.

  The resin obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after the polymerization reaction is completed, the target resin is recovered as a powder by putting the polymerization solution into a reprecipitation solvent. As a reprecipitation solvent, the solvent illustrated as the said polymerization solvent can be used individually or in mixture of 2 or more types. In addition to the reprecipitation method, the resin can be recovered by removing low molecular components such as monomers and oligomers by a liquid separation operation. That is, after completion of the polymerization reaction, the polymerization solution is appropriately concentrated, for example, a solvent system that separates into two liquids such as methanol / heptane is selected and added, and the low molecular components are removed from the resin solution, and the necessary solvent system ( And the desired resin is recovered as a solution.

  In addition, although the polymer (A) contains a low molecular weight component derived from a monomer, the content thereof is 0.1% by mass or less with respect to the total amount (100% by mass) of the polymer (A). It is preferable that it is 0.07 mass% or less, and it is especially preferable that it is 0.05 mass% or less.

  When the content of this low molecular weight component is 0.1% by mass or less, a resist film is prepared using this polymer (A), and the water in contact with the resist film is subjected to immersion exposure. It is possible to reduce the amount of eluate in Furthermore, no foreign matter is deposited in the resist during resist storage, and coating unevenness does not occur during resist application. Therefore, it is possible to sufficiently suppress the occurrence of defects when forming a resist pattern.

  In the present specification, when the term “low molecular weight component” derived from a monomer is used, the polystyrene-reduced weight average molecular weight (hereinafter sometimes referred to as “Mw”) by gel permeation chromatography (GPC) is Mw500. It shall mean the following ingredients. Specifically, it is a component such as a monomer, dimer, trimer or oligomer. This “low molecular weight component” can be removed by, for example, chemical purification methods such as washing with water, liquid-liquid extraction, and the like, and chemical purification methods combined with physical purification methods such as ultrafiltration and centrifugation. it can.

  The low molecular weight component can be quantified by analyzing the polymer (A) by high performance liquid chromatography (HPLC). In addition to the low molecular weight component, the polymer (A) is preferably as low as possible impurities such as halogen and metal, thereby further improving the sensitivity, resolution, process stability, pattern shape, etc. when used as a resist. Can do.

  The polymer (A) preferably has a repeating unit (1) represented by the following general formula (1).

(In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 4 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, R ³ and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or R ³ and R ⁴ are bonded to each other And a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms formed together with the carbon atom to which both are bonded.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ² , R ³ and R ^{4 in the} general formula (1) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, An i-butyl group can be exemplified, and among them, a methyl group, an ethyl group, and an i-propyl group are preferable. Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ² , R ³ and R ⁴ include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a norbornyl group, and a tricyclodecyl group. , Tetracyclododecyl group, adamantyl group and the like. Furthermore, R ³ and R ⁴ are bonded to each other, and the divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms formed together with the carbon atom to which both are bonded includes the above monovalent alicyclic ring. And a group obtained by removing one hydrogen atom from the formula hydrocarbon group.

As the repeating unit (1), repeating units represented by the following general formulas (1-1) to (1-20) are particularly preferable. These may be used alone or in combination of two or more.

(In the formula, the definition of R ¹ is the same as in the above formula (1).)

  The content of the repeating unit (1) is preferably 1 mol% or more and 80 mol% or less, more preferably 1 mol% or more and 70 mol% or less, based on all repeating units constituting the polymer [A]. % To 70 mol% is particularly preferable. When the content of the repeating unit (1) is in the above range, the radiation-sensitive resin composition can exhibit resist characteristics in which resolution, MEEF, and LWR are highly balanced. When the amount is less than 1 mol% or exceeds 80 mol%, the resolution performance as a resist may deteriorate.

The polymer (A) preferably contains at least one selected from repeating units having a lactone skeleton and repeating units having a cyclic carbonate skeleton (hereinafter also referred to as “repeating unit (2)”). As the repeating unit (2), a repeating unit represented by the following formula is preferred.

(In the above general formula, R ⁵ and R ⁶ each independently represent hydrogen or a methyl group, R ⁷ represents a hydrogen atom or a methoxy group, R ⁸ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a cyano group. Represents a group, A represents a single bond or methylene, B represents methylene or oxygen, and l and m are integers of 0 or 1.)

  As the repeating unit (2), a repeating unit represented by the following formula is particularly preferable.

  In the polymer (A), the content of the repeating unit (2) is such that the total amount of the repeating unit (2) is 10 to 70 mol% with respect to all the repeating units constituting the polymer (A). Preferably, it is 20-60 mol%, and it is still more preferable. By setting it as such a content rate, the developability as a resist, defect property, low LWR, low PEB temperature dependence, etc. can be improved. On the other hand, if it exceeds 70 mol%, the resolution as a resist and LWR may be lowered.

  Moreover, a polymer (A) may contain 1 or more types of repeating units which have a polar group represented by a following formula.

Furthermore, the polymer (A) includes methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylic acid-bicyclo [2.2.1] heptyl ester, (meth) acrylic acid-cyclohexyl ester, (meth) acrylic acid-bicyclo [4.4.0] decanyl ester, (meth) acrylic acid-bicyclo [2.2.2] ] Octyl ester, (meth) acrylic acid-tricyclo [5.2.1.0 ^2,6 ] decanyl ester, (meth) acrylic acid-adamantyl, (meth) acrylic acid-tricyclo [3.3.1.1] ^3,7 ] It may contain a repeating unit derived from an alkyl (meth) acrylate such as decanyl ester.

  In the radiation-sensitive resin composition of the present invention, the polymer (A) may be used alone or in combination of two or more. Moreover, you may mix and use a polymer (A) and the other polymer which does not contain an alicyclic hydrocarbon skeleton at the terminal of a molecular chain. In this case, the ratio of the polymer (A) in the total polymer is 5% by mass or more, preferably 10% by mass or more, and particularly preferably 15% by mass or more. If it is less than 5% by mass, there is a possibility that resist characteristics in which resolution, MEEF and LWR are highly balanced cannot be exhibited.

Solvent (B):
The radiation sensitive resin composition of the present invention contains a solvent. The solvent is not particularly limited as long as it can dissolve at least the polymer (A) and optional components. Examples thereof include alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents, and mixed solvents thereof.

Examples of alcohol solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, and 2-methylbutanol. , Sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethyl Hexanol, sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, se - heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methyl cyclohexanol, 3,3,5-trimethyl cyclohexanol, benzyl alcohol, mono-alcohol solvents such as diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n. -Hexyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, 2-hexanone, methylcyclohexanone, 2,4-pentanedione, acetonyl acetone, diacetone alcohol, Examples include ketone solvents such as acetophenone and fenchon.

Examples of the amide solvent include N, N-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone and the like can be mentioned.

Examples of ether solvents include ethyl ether, iso-propyl ether, n-butyl ether, n-hexyl ether, 2-ethylhexyl ether, dioxolane, 4-methyldioxolane, dioxane, dimethyldioxane, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether. , Ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-n-hexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, ethylene glycol dibutyl ether, diethylene glycol Monomethyl ether, diethylene glycol dimethyl ether, diethylene Recall monoethyl ether, diethylene glycol diethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol di-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol di-n-butyl ether, propylene glycol monomethyl ether, propylene Examples include glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, diphenyl ether, and anisole.

Examples of the ester solvent include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, and acetic acid. sec-butyl, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, aceto Methyl acetate, ethyl acetoacetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene acetate Recall mono-n-butyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, diacetic acid Glycol, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate , Diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of other solvents include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, and cyclohexane. , Aliphatic hydrocarbon solvents such as methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propyl benzene, iso-propyl benzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propyl benzene, n-amylnaphthalene Group hydrocarbon solvents;
Mention may be made of halogen-containing solvents such as dichloromethane, chloroform, freon, chlorobenzene and dichlorobenzene.

Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, γ-butyrolactone, and ethyl lactate are preferable. These solvents can be used alone or in combination of two or more. When these solvents are used, the resist coating properties, the storage stability, and the residual solvent ratio in the resist film after forming the resist film are balanced.

Optional component In addition to the polymer (A) and the solvent (B), the radiation-sensitive resin composition of the present invention includes, as an optional component, an acid generator, fluorine, as long as the effects of the present invention are not impaired. Containing resin, alicyclic skeleton containing compound, surfactant, acid diffusion controller, sensitizer and the like can be contained. The compounding quantity of an arbitrary component can be suitably determined according to the purpose.

(Acid generator)
The acid generator is a component that generates an acid upon exposure. The acid dissociable group present in the polymer (A) is dissociated by the acid, and as a result, the polymer (A) becomes readily soluble in an alkali developer. As the inclusion form in the radiation sensitive resin composition of the acid generator, either in the form of a free compound as described later, in the form incorporated as part of the polymer (A) or the other polymer described above, Both of these forms may be used.

  Examples of the acid generator include onium salt compounds, sulfonimide compounds, halogen-containing compounds, diazoketone compounds, and the like. Of these acid generators, onium salt compounds are preferred.

  Examples of the onium salt compounds include sulfonium salts (including tetrahydrothiophenium salts), iodonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like. Of these onium salt compounds, sulfonium salts are preferred.

  Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept. 2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium camphorsulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4- Cyclohexylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenyl Rusulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium camphorsulfonate, 4-methanesulfonylphenyldiphenylsulfonium trifluoromethanesulfonate 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept- 2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium camphorsulfonate, etc. It is. Of these, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate and triphenylsulfonium perfluoro-n-butanesulfonate are preferable, and triphenylsulfonium perfluoro-n-butanesulfonate is more preferable.

  Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium. Nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothio Phenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium camphor Sulfonate, 1- (6-n-butoxynaphthalen-2-yl) Tetrahydrothiophenium trifluoromethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothio Phenium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2, 2-tetrafluoroethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium camphorsulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl- -Hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl -4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4- Hydroxyphenyl) tetrahydrothiophenium camphorsulfonate and the like. Of these tetrahydrothiophenium salts, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) Tetrahydrothiophenium perfluoro-n-octane sulfonate and 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butane sulfonate are preferred.

  Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl. -1,1,2,2-tetrafluoroethanesulfonate, diphenyliodonium camphorsulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate Bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2. .1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t- butylphenyl) iodonium camphorsulfonate, and the like. Of these iodonium salts, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate is preferred.

  Examples of the sulfonimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy) bicyclo. [2.2.1] Hept-5-ene-2,3-dicarboximide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3 -Dicarboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept-5 Ene-2,3-dicarboximide, N- (2- (3-tetracyclo [4.4.0.12,5.17,10] dodecanyl) -1,1-difluoroethanesulfonyl Xyl) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-di Carboximide etc. can be mentioned. Of these sulfonimide compounds, N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide is preferred.

  The acid generator can be used alone or in combination of two or more. The amount used in the case of using the acid generator is usually 0.1 parts by mass or more and 10 parts by mass or less, preferably 100 parts by mass or less, with respect to 100 parts by mass of the polymer (A), from the viewpoint of ensuring sensitivity and developability as a resist. Is 0.5 parts by mass or more and 9 parts by mass or less. In this case, if the amount of the acid generator used is less than 0.1 parts by mass, the sensitivity and developability tend to decrease. On the other hand, if it exceeds 10 parts by mass, the transparency to radiation decreases and a rectangular resist pattern. Tends to be difficult to obtain.

(Acid diffusion controller)
The acid diffusion controller is a component that controls the diffusion phenomenon of the acid generated from the acid generator upon exposure in the resist film. Specifically, it has the effect of suppressing undesirable chemical reactions in the non-exposed areas, and as a result, the storage stability of the resulting radiation-sensitive resin composition is further improved, and the resolution as a resist is further improved. Thus, a change in the line width of the resist pattern due to a change in the holding time from exposure to development processing can be suppressed, and a composition having excellent process stability can be obtained. The inclusion form of the acid diffusion controller in the radiation-sensitive resin composition may be either a free compound form or a form incorporated as part of the polymer (A) or the other polymer mentioned above. It may be a form.

As the acid diffusion controller, a compound showing basicity in a non-exposed region is generally used. Specifically, a nitrogen-containing basic compound such as a tertiary amine compound or a quaternary ammonium hydroxide compound; a compound having a structure in which a —COOR group (where R represents an acid-dissociable group) is bonded to a nitrogen atom; Examples include onium salts that lose basicity by generating weak acids upon exposure.
The acid diffusion inhibitor can be used alone or in combination of two or more. The content ratio of the low-molecular acid diffusion controller is preferably less than 5 parts by mass, more preferably less than 1 part by mass with respect to 100 parts by mass of the total polymer. When the total amount used exceeds 5 parts by mass, the sensitivity as a resist tends to be remarkably lowered.

(Fluorine-containing resin)
The fluorine-containing resin exhibits an action of developing water repellency on the resist film surface particularly in immersion exposure. In addition, it has the effect of suppressing elution of components from the resist film to the immersion liquid, and even when immersion exposure is performed by high-speed scanning, it does not leave droplets, resulting in immersion-derived defects such as watermark defects. There is an effect to suppress.

As the structure of the fluorine-containing resin, for example,
A fluorine-containing resin which itself is insoluble in a developer and becomes alkali-soluble by the action of an acid;
A fluorine-containing resin which is itself soluble in a developer and whose alkali solubility is increased by the action of an acid;
A fluorine-containing resin which itself is insoluble in a developer and becomes alkali-soluble by the action of alkali;
Examples thereof include a fluorine-containing resin which is itself soluble in a developer and whose alkali solubility is increased by the action of an alkali.

As the fluorine-containing resin, a polymer having a fluorine-containing repeating unit is preferable. Examples of the monomer that gives a fluorine-containing repeating unit include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, Perfluoro n-propyl (meth) acrylic acid ester, perfluoro i-propyl (meth) acrylic acid ester, perfluoro n-butyl (meth) acrylic acid ester, perfluoro i-butyl (meth) acrylic acid ester, perfluoro t-butyl (meth) acrylic acid ester, 2- (1,1,1,3,3,3-hexafluoropropyl) (meth) acrylic acid ester, 1- (2,2,3,3,4,4 , 5,5-octafluoropentyl) (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) ) Acrylic acid ester, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylic acid ester, 1- (3,3,4,4,5,5,6,6,7, 7,8,8,9,9,10,10,10-heptadecafluorodecyl) (meth) acrylic acid ester, 1- (5-trifluoromethyl-3,3,4,4,5,6,6 , 6-octafluorohexyl) (meth) acrylic acid ester and the like.

As a fluorine-containing resin, the copolymer etc. which have the said fluorine-containing repeating unit and the repeating unit which comprises a polymer (A) are preferable, for example. These fluorine-containing resins can be used alone or in combination of two or more.

(Alicyclic skeleton-containing compound)
The alicyclic skeleton-containing compound has an effect of improving dry etching resistance, pattern shape, adhesion to the substrate, and the like.

Examples of the alicyclic skeleton-containing compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylate t-butyl;
Deoxycholic acid esters such as t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholic acid, 2-ethoxyethyl deoxycholic acid;
Lithocholic acid esters such as t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid;
3- [2-hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.12,5.17,10] dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo- 4-oxa-tricyclo [4.2.1.03,7] nonane and the like can be mentioned. These alicyclic skeleton-containing compounds can be used alone or in combination of two or more.

(Surfactant)
Surfactants have the effect of improving coatability, striation, developability, and the like.

Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol In addition to nonionic surfactants such as distearate, KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (Kyoeisha Chemical Co., Ltd.), Ftop EF301 (Tochem Products), Ftop EF303 (Tochem Products), Ftop EF352 (Tochem Products), MegaFuck F171 (Dainippon Ink and Chemicals), Mega Fax F173 (Dainippon Ink and Chemicals), Florard FC430 (Sumitomo 3M), Florard FC431 (Sumitomo 3M), Asahi Guard AG710, Surflon S-382 (Asahi Glass Industry), Surflon SC-101 (Asahi Glass Industry) Surflon SC-102 (Asahi Glass Industrial Co., Ltd.), Surflon SC-103 (Asahi Glass Industrial Co., Ltd.), Surflon SC-104 (Asahi Glass Industrial Co., Ltd.), Surflon SC-105 (Asahi Glass Industrial Co., Ltd.), Surflon SC-106 (Asahi Glass Industrial Co., Ltd.) Etc. These surfactants can be used alone or in combination of two or more.

(Sensitizer)
The sensitizer absorbs energy other than the energy of the radiation absorbed by the acid generator and transmits the energy to the acid generator in the form of electrons or radicals, thereby increasing the amount of acid produced. And has the effect of improving the “apparent sensitivity” of the radiation-sensitive resin composition.

Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, and phenothiazines. These sensitizers can be used alone or in combination of two or more.

(Other optional ingredients)
Other optional components include, for example, dyes, pigments, adhesion aids, alkali-soluble resins, low-molecular alkali solubility control agents having acid-dissociable protecting groups, antihalation agents, storage stabilizers, antifoaming agents. Etc. Among these, for example, when a dye or a pigment is blended, the latent image in the exposed area can be visualized and the influence of halation during exposure can be reduced. Further, when an adhesion assistant is blended, the adhesion to the substrate can be improved. These other optional components can be used alone or in combination of two or more.

(Photoresist pattern formation method)
As a method for forming a photoresist pattern, for example, the following method is generally used. Using the radiation-sensitive resin composition, a step of forming a photoresist film on the substrate (hereinafter also referred to as step (i)), the formed photoresist film through an immersion medium as necessary, It is also referred to as a step of exposing by exposure to radiation through a mask having a predetermined pattern (hereinafter also referred to as step (ii)) and a step of heating the substrate (exposed photoresist film) (hereinafter referred to as step (iii)). ) And a development step (hereinafter also referred to as step (iv)), a photoresist pattern can be formed.

In the step (i), a radiation sensitive resin composition or a composition solution obtained by dissolving it in a solvent is applied to a substrate (silicon wafer, silicon dioxide) by a coating means such as spin coating, cast coating, roll coating or the like. A photoresist film is formed by applying a resin composition solution to a predetermined film thickness on a wafer coated with an antireflection film, etc., and then pre-baking to volatilize the solvent in the coating film. To do.

In step (ii), the photoresist film formed in step (i) is irradiated with radiation (possibly through an immersion medium such as water) and exposed. At this time, radiation is irradiated through a mask having a predetermined pattern. As the radiation, irradiation is performed by appropriately selecting from visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams and the like according to the line width of the target pattern. Far ultraviolet rays represented by ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm) are preferable, and ArF excimer laser is more preferable.

Step (iii) is called PEB and is a step in which the acid generated from the acid generator [B] deprotects the polymer in the exposed portion of the photoresist film in step (ii). PEB is usually carried out by appropriately selecting in the range of 50 ° C to 180 ° C.

In step (iv), the exposed photoresist film is developed with a developer to form a predetermined photoresist pattern. After development, it is common to wash with water and dry. Examples of the developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, Ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4.3.0 An alkaline aqueous solution in which at least one alkaline compound such as -5-nonene is dissolved is preferable.

In addition, when performing immersion exposure, before the step (ii), in order to protect the direct contact between the immersion liquid and the resist film, an immersion liquid insoluble immersion protective film is formed on the resist film. It may be provided. Examples of the immersion protective film include a solvent-peelable protective film (see, for example, JP-A-2006-227632) that is peeled off by a solvent before the step (iv), and a development that peels off simultaneously with the development in the step (iv). Any of liquid-removable protective films (see, for example, WO2005-069096 and WO2006-035790) may be used. However, from the viewpoint of throughput, it is preferable to use a developer peeling type immersion protective film.

  The resist pattern thus obtained is suitable for fine processing using a lithography technique because the top loss is prevented, the rectangularity is good, and the LWR and pattern collapse are suppressed.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are shown below.

  [Weight average molecular weight (Mw) and number average molecular weight (Mn)]: GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, flow rate: 1.0 ml / min, elution solvent: tetrahydrofuran, column temperature : Measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under analysis conditions of 40 ° C. The degree of dispersion (Mw / Mn) was calculated from the measurement results.

[ ¹³ C-NMR analysis]: The ¹³ C-NMR analysis was measured using “JNM-EX270” manufactured by JEOL Ltd.

  Hereinafter, synthesis examples of the resin (A) will be described. In addition, the kind of monomer used for the synthesis | combination of resin (A) is shown below as Formula (M-1)-(M-12).

(Synthesis Example 1 Preparation of Resin (A-1))
13.0 g (50 mol%) of a monomer represented by the formula (M-1) (hereinafter also referred to as “monomer (M-1)”), a monomer represented by the formula (M-7) (Hereinafter also referred to as “monomer (M-7)”) 2.9 g (10 mol%) and a monomer represented by formula (M-11) (hereinafter “monomer (M-9)”) (Also called) 10.3 g (30 mol%) is dissolved in 60 g of 2-butanone, and 0.36 g of a polymerization initiator “V-601” manufactured by Wako Pure Chemical Industries, Ltd. having the structure of the above formula (a3) is further added. A charged monomer solution was prepared. On the other hand, a monomer represented by the formula (M-5) (hereinafter also referred to as “monomer (M-5)”) 3.8 g (10 mol%) dissolved in 30 g of 2-butanone The body solution was put into a 200 ml three-necked flask and purged with nitrogen for 30 minutes, and then the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was dropped over 3 hours using a dropping funnel. . The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After the completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or less, poured into 600 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 150 g of methanol in the form of a slurry and then filtered again and dried at 50 ° C. for 17 hours to obtain a white powder copolymer. Mw of the obtained copolymer was 18000, Mw / Mn was 1.74, the yield was 82.4%, and the ratio of repeating units derived from each monomer in the copolymer ( The monomer (M-1) / monomer (M-5) / monomer (M-7) / monomer (M-11)) are mol%, 49.0 / 9.2 / 10. 1 / 31.6. This copolymer is referred to as “resin (A-1)”. Table 1 shows the types of monomers used in Synthesis Example 1 and the formulation. In addition, Table 2 shows the measurement results of Mw, Mw / Mn, yield, and the ratio of repeating units derived from each monomer in the copolymer.

(Synthesis Examples 2 to 20 Synthesis of Resins (A-2) to (A-20))
A copolymer was prepared in the same manner as in Synthesis Example 1 except that the types of monomers and initiators shown in Table 1 were used in the formulation shown in Table 1. The description of the polymerization initiator in the table is as follows: “V-501” is an initiator made by Wako Pure Chemicals having the structure of the above formula (a2); It is a manufacturing initiator. In addition, Table 2 shows the measurement results of Mw, Mw / Mn, yield of the obtained copolymer, and the ratio of the repeating unit derived from each monomer in the copolymer. Let each copolymer be resin (A-2)-(A-20).

(Example 1 Preparation of radiation-sensitive resin composition)
Resin (A-1) 100 parts prepared in Synthesis Example 1, acid generator (B-1) 3.6 parts, acid generator (B-2) 10.6 parts, acid diffusion inhibitor (C) 1. 7 parts, 0.02 part of additive (D), 1700 parts of solvent (E-1), 700 parts of solvent (E-2), and 30 parts of solvent (E-3) are mixed to produce a radiation sensitive resin composition. Was prepared.

(Examples 2 to 11 and Comparative Examples 1 to 9 Preparation of radiation-sensitive resin composition)
A radiation sensitive resin composition was prepared in the same manner as in Example 1 except that the formulation shown in Table 3 was used.

  Details of the acid generator (B), the acid diffusion inhibitor (C), the additive (D), and the solvent (E) are shown below.

  Acid generator (B)

(B-1): Triphenylsulfonium 2- (adamantan-1-yl) -1,1-difluoroethane-1-sulfonate (B-2): Triphenylsulfonium 2- (adamantanecarbonyloxy) -1,1,2 , 2-Tetrafluorohexane-1-sulfonate

Acid diffusion inhibitor (C)
(C): Nt-butoxycarbonyl-4-hydroxypiperidine

Additive (D)
(D): DAINAFLOW (manufactured by Neos)

Solvent (E)
(E-1): Propylene glycol monomethyl ether acetate (E-2): Cyclohexanone (E-3): γ-butyrolactone

Evaluation of Radiation Sensitive Resin Composition The radiation sensitive resin compositions of Examples 1 to 11 and Comparative Examples 1 to 9 were subjected to various evaluations as follows. These evaluation results are shown in Table 4.

[Development defects]:
First, a film having a film thickness of 110 nm is formed from a radiation-sensitive resin composition on a 12-inch silicon wafer on which an underlayer antireflection film (“ARC66”, manufactured by Nissan Chemical Co., Ltd.) is formed. Soft bake (SB) was performed for 2 seconds. Next, this film is exposed through a mask pattern using an ArF excimer laser immersion exposure apparatus (“NSR S610C”, manufactured by NIKON) under the conditions of NA = 1.3, ratio = 0.800, Dipole. did. After the exposure, post-baking (PEB) was performed at 95 ° C. or 120 ° C. for 60 seconds. Thereafter, the resist film was developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution, washed with water, and dried to form a positive resist pattern. At this time, the exposure amount for forming a line and space having a width of 45 nm was determined as the optimum exposure amount. With this optimum exposure amount, a line and space having a line width of 45 nm was formed on the entire surface of the wafer to obtain a defect inspection wafer. A scanning electron microscope (“CC-4000”, manufactured by Hitachi High-Technologies Corporation) was used for length measurement.

Thereafter, the number of defects on the defect inspection wafer was measured using “KLA2810” manufactured by KLA-Tencor. Furthermore, the defects measured by “KLA2810” were classified into those judged to be resist-derived and foreign matters derived from the outside. After classification, when the total number of defects (number of defects) determined to be derived from the resist film was less than 500 / wafer, it was judged as “good”, and when it was 500 or more and less than 1000, “somewhat good”, 1000 When it exceeded the number of pieces / wafer, it was determined as “bad”.

  As can be seen from Table 4, it was confirmed that the radiation-sensitive resin composition of the present invention had fewer development defects than Comparative Examples 1-9.

  The radiation-sensitive resin composition of the present invention can be suitably used for photoresists that require increasingly finer line widths of resist patterns in the future.

Claims (3)

(A) It has a carbonyl group at at least one end of the molecular chain, and has a polystyrene-reduced weight average molecular weight of 11,000 or more by gel permeation chromatography, and is decomposed by the action of an acid to increase the solubility in an alkali developer. A radiation-sensitive resin composition comprising a polymer and (B) a radiation-sensitive acid generator. The radiation sensitive resin composition according to claim 1, wherein the polymer (A) further has at least one selected from a repeating unit having a lactone structure and a repeating unit having a cyclic carbonate structure. A polymer having a carbonyl group at at least one end of a molecular chain and having a polystyrene-reduced weight average molecular weight of 11,000 or more by gel permeation chromatography, which is decomposed by the action of an acid and increases the solubility in an alkali developer.