JP2004300403A - (meth) acrylic polymer and radiation-sensitive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a resin composition having high transparency for radiation rays, excellent in basic physical properties as a resist such as sensitivity, resolution, dry etching resistance, a pattern shape and the like, and reduced in line edge roughness of the pattern after development. <P>SOLUTION: The (meth)acrylic polymer comprises at least one repeating unit selected from repeating units expressed by from formula (1) and formula (2) (wherein R expresses H or methyl; R<SP>1</SP>expresses H, a 1-7C alkyl which may have a substituent; R<SP>2</SP>expresses a 3-7C straight chain or branched alkyl. an alicyclic alkyl; X expresses methylene or ethylene). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radiation-sensitive resin composition, and particularly to fine processing using various radiations such as X-rays such as KrF excimer laser or ArF excimer laser, X-rays such as synchrotron radiation, and electron beams. The present invention relates to a (meth) acrylic polymer which becomes a chemically amplified resist material useful for the present invention, and a radiation-sensitive resin composition using the polymer.

In field of microfabrication represented by fabrication of integrated circuit devices, in order to achieve a higher degree of integration, ArF excimer laser (wavelength 193 nm) has recently, F ₂ excimer laser (wavelength 157 nm) or less 200nm about using such There is a need for a lithography technology capable of microfabrication at a level. Such a radiation-sensitive resin composition suitable for irradiation with an excimer laser is a chemistry utilizing a chemical amplification effect of a component having an acid-dissociable functional group and an acid generator which is a component that generates an acid upon irradiation with radiation. Many amplified radiation-sensitive compositions have been proposed. For example, as resin components, 8-acryloxy-4-oxatricyclo [5.2.1.0 ^2,6 ] decane-3-one and 9-acryloxy-4-oxatricyclo [5.2.1. A polymer compound for a photoresist using a mixture of [ ^2,6 ] decane-3-one as a monomer is known (see Patent Document 1).
JP-A-2002-275215 (paragraphs [0130] to [0133])

  However, in the field of semiconductors, when a higher degree of integration than before has been required, a radiation-sensitive resin composition as a resist has been required to have better resolution. At the same time, with further miniaturization, there have been many cases in which minute defects generated during development become fatal defects in device design. In order to cope with such a situation, development to improve the process margin such as the resolution and the exposure amount dependency as a resist is naturally proceeding.However, it is considered that minute defects generated during development are caused by the resin as a component. In consideration of this, it is also urgently required to increase the solubility in a resist solvent or the like. At present, the (meth) acrylic resin generally used has a rigid main chain grafted with a rigid side chain, and is extremely resistant to a general organic solvent-based resist solvent used for a resist. It is believed that the solubility is low. For this reason, there is a problem that there is no radiation-sensitive resin composition corresponding to a high degree of integration in recent years.

  The present invention has been made to address such a problem, and by using a (meth) acrylic polymer having a specific structure and this polymer, the transparency to radiation is high, and the sensitivity and resolution are high. It has excellent basic physical properties as a resist such as dry etching resistance and pattern shape, and is particularly useful for a radiation-sensitive resin composition which has excellent solubility in a resist solvent and reduces line edge roughness of a pattern after development ( An object of the present invention is to provide a (meth) acrylic polymer and a radiation-sensitive resin composition using the polymer.

式（１）および式（２）において、Ｒは水素原子またはメチル基を表し、Ｒ¹は水素原子または炭素数１〜７の置換基を有していてもよいアルキル基、または、アルコキシ基を表し、Ｒ²は炭素数３〜７の直鎖状もしくは分岐状のアルキル基、または脂環式のアルキル基を表し、Ｘはメチレン基またはエチレン基を表す。
また、上記式（１）または式（２）とともに、下記式（３）で表される繰り返し単位を含むことを特徴とする。

式（３）において、Ｒは水素原子またはメチル基を表し、Ｒ³は相互に独立に炭素数４〜２０の１価の脂環式炭化水素基もしくはその誘導体または１〜４の直鎖状もしくは分岐状のアルキル基を表し、かつＲ³の少なくとも１つが該脂環式炭化水素基もしくはその誘導体であるか、あるいは何れか２つのＲ³が相互に結合して、それぞれが結合している炭素原子とともに炭素数４〜２０の２価の脂環式炭化水素基もしくはその誘導体を形成し、残りのＲ³が炭素数１〜４の直鎖状もしくは分岐状のアルキル基または炭素数４〜２０の１価の脂環式炭化水素基もしくはその誘導体を表す。 The (meth) acrylic polymer of the present invention is characterized by containing at least one repeating unit selected from the repeating units represented by the following formulas (1) and (2).

In the formulas (1) and (2), R represents a hydrogen atom or a methyl group, and R ¹ represents a hydrogen atom or an alkyl group which may have a substituent having 1 to 7 carbon atoms, or an alkoxy group. R ² represents a linear or branched alkyl group having 3 to 7 carbon atoms or an alicyclic alkyl group, and X represents a methylene group or an ethylene group.
Further, it is characterized by containing a repeating unit represented by the following formula (3) together with the above formula (1) or (2).

In the formula (3), R represents a hydrogen atom or a methyl group, and R ³ independently of each other, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or linear 1 to 4 carbon atom. Represents a branched alkyl group, and at least one of R ³ is the alicyclic hydrocarbon group or a derivative thereof, or any two R ³ are bonded to each other to form a carbon to which each is bonded. Forming a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof together with the atoms, and the remaining R ³ is a linear or branched alkyl group having 1 to 4 carbon atoms or 4 to 20 carbon atoms; Represents a monovalent alicyclic hydrocarbon group or a derivative thereof.

  The radiation-sensitive resin composition of the present invention is a radiation-sensitive resin containing an acid-dissociable group-containing resin that is alkali-insoluble or hardly soluble in alkali and becomes easily alkali-soluble by the action of an acid, and a radiation-sensitive acid generator. A resin composition, wherein the acid-dissociable group-containing resin contains the (meth) acrylic polymer.

Since the radiation-sensitive resin composition of the present invention is a (meth) acrylic resin containing a repeating unit represented by the formula (1) and / or the formula (2), the rigidity of the side chain may be inhibited. The solubility in a solvent is improved. Further, since R ¹ and R ² are predetermined substituents, the solubility in the resist solvent and the developing solution can be set in an optimum range, and the line edge roughness can be reduced. As a result, as a chemically amplified resist that is sensitive to actinic radiation, in particular, far ultraviolet rays typified by ArF excimer laser (wavelength 193 nm), it has high transparency to radiation and good sensitivity, resolution, dry etching resistance, and pattern shape. Not only does it have basic performance as a resist, but firstly, it has extremely high solubility in resist solvents, and secondly, it is possible to reduce pattern line edge roughness after development. .

As the pattern miniaturization in lithography technology progresses, there have been many cases in which minute defects generated during development become fatal defects in device design. When the cause was studied, it was found that the solubility of the resin component constituting the radiation-sensitive resin composition as a resist in a solvent such as propylene glycol monomethyl ether acetate was caused. When the solubility in a resist solvent is improved, the solubility in an aqueous developer tends to decrease. Therefore, it is important to improve the solubility in the resist solvent and not to lower the solubility in the developer. It turned out to be.
The (meth) acrylic resin used as a resin component is considered to have extremely low solubility because a rigid side chain is formed in a rigid main chain, but the formula (1) and / or the formula (1) By using a (meth) acrylic resin containing the repeating unit represented by (2), the rigidity of the side chain can be inhibited. As a result, the solubility in the solvent is improved. Further, by setting R ¹ and R ² to predetermined substituents, the solubility in a resist solvent and a developing solution can be set in an optimum range, and line edge roughness can be reduced.

式（１−１）および式（２−１）におけるＲは水素原子またはメチル基を表し、Ｘはメチレン基またはエチレン基を表す。 As a monomer that forms a repeating unit represented by the formula (1) that forms a polymer main chain, a (meth) acrylate represented by the formula (1-1) is represented by the formula (2). Examples of the monomer that generates the repeating unit include (meth) acrylic acid esters represented by the formula (2-1).

In the formulas (1-1) and (2-1), R represents a hydrogen atom or a methyl group, and X represents a methylene group or an ethylene group.

R ¹ in the above formulas (1-1) and (2-1) represents a hydrogen atom or an alkyl group which may have a substituent having 1 to 7 carbon atoms or an alkoxy group, and an alkyl group As methyl, ethyl, n-propyl, i-propyl, n-butyl, 2-methylpropyl, 1-methylpropyl, t-butyl, pentyl, hexyl, heptyl, etc. And a monocyclic alicyclic alkyl group such as a linear or branched alkyl group and a cyclohexyl group.
Examples of the alkoxy group include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, 2-methylpropoxy, 1-methylpropoxy, t-butoxy, pentyloxy, hexyl. Examples thereof include a linear or branched alkyloxy group such as an oxy group and a heptyloxy group, and a monocyclic alicyclic alkyloxy group such as a cyclohexyloxy group.
R ² in the above formulas (1-1) and (2-1) represents a linear or branched alkyl group having 3 to 7 carbon atoms or an alicyclic alkyl group, Examples of the branched alkyl group include n-propyl, i-propyl, n-butyl, 2-methylpropyl, 1-methylpropyl, t-butyl, pentyl, hexyl, and heptyl. Monocyclic alicyclic alkyl groups such as linear or branched alkyl groups and cyclohexyl groups are exemplified.
Preferred (meth) acrylates represented by the formula (1-1) or (2-1) are represented by the following formula (1-1-a) or (2-1-a) ( (Meth) acrylates. Here, X, R, R ¹ and R ² are the same as those in the above formulas (1-1) and (2-1).

Specific examples of the monomers represented by the formulas (1-1) and (2-1) are shown below. R represents a hydrogen atom or a methyl group.

The monomer represented by the formula (1-1) or the formula (2-1) is obtained by preparing a 1,3-diene having a substituent corresponding to R ¹ or R ² at the 1,4-position and maleic anhydride. Is subjected to a Diels-Alder reaction to selectively reduce, for example, 1,4-dialkyl-5-norbornene-2,3-dicarboxylic anhydride and the like. It can be produced by (meth) acrylic esterification.
The method of reducing the Diels-Alder addition product of 1,3-diene and maleic anhydride to olefin lactone is not particularly limited, but usually, as a reducing agent, for example, lithium aluminum hydride or a part of its hydrogen atom is converted to an alcoholate. A reduction method using a substituted one, or a reducing agent in which sodium borohydride or a part of its hydrogen atom is replaced by an alcoholate, may be mentioned. The reduction reaction is preferably performed in an ether solvent such as ethyl ether or tetrahydrofuran. The reducing agent is preferably used in a stoichiometric or excess amount. The reduction reaction can be generally carried out at -100 ° C to 100 ° C. However, when lithium aluminum hydride or a part of its alcoholate is used, it is preferably carried out at -78 ° C to -20 ° C. When a part of alcoholate is used, it is preferably carried out at -20 ° C to 100 ° C. After completion of the reaction, an acid is added to decompose the reducing agent or its oxidized product, and then the desired product is obtained by extraction and washing with water, and can be subjected to the above-mentioned reaction with a carboxylic acid. Of course, if desired, purification can be carried out by conventional means such as distillation, crystallization and chromatography.
The method for hydrating the carbon-carbon double bond of the obtained lactone is not particularly limited, and examples thereof include (i) a method of oxidative hydrolysis after water boration, and (ii) an acid catalyst such as trifluoromethanesulfonic acid. Preferably, a method of hydrolyzing an ester obtained by adding a lower carboxylic acid such as formic acid in the presence of is used. The alcohol obtained in this way is (meth) acryl-esterified to obtain a monomer represented by the above formula (1-1) or (2-1). The monomer represented by the formula (1-1) or the formula (2-1) depends on which carbonyl group of the acid anhydride group is reduced in the reduction reaction of the Diels-Alder addition product, respectively. Generate. As a method of (meth) acrylic esterification, for example, (meth) acrylic acid halide, (meth) acrylic anhydride, (meth) acrylic acid, or (meth) acrylic acid ester is reacted with alcohol to form an ester. Method.

In the formula (3), R ^{3 is} a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or at least one is an alicyclic hydrocarbon group or a derivative thereof, or any two of them. Examples of the bivalent alicyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atoms to which R ³ is bonded together and the carbon atoms to which each is bonded or a derivative thereof include bicyclo [2.2.1] heptane, Tricyclo [5.2.1.0 ^2,6 ] decane, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] a group consisting of alicyclic rings derived from cycloalkanes such as dodecane, cyclobutane, cyclopentane, cyclohexane and the like; groups consisting of these alicyclic rings include, for example, methyl group, ethyl group, n-propyl One kind of a linear, branched or cyclic alkyl group having 1 to 4 carbon atoms such as a group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, etc. Examples of the group include one or more or one or more substituted groups.

Examples of the derivative of a monovalent or divalent alicyclic hydrocarbon group of R ³ include a hydroxyl group; a carboxyl group; an oxo group (that is, an 即 ち O group); a hydroxymethyl group, a 1-hydroxyethyl group, C1-C4 hydroxy such as 2-hydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl, 3-hydroxybutyl, and 4-hydroxybutyl; Alkyl group; C1-C4 alkoxyl group such as methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy group. A cyano group; a cyano group having 2 to 5 carbon atoms such as a cyanomethyl group, a 2-cyanomethyl group, a 3-cyanopropyl group, and a 4-cyanobutyl group; A group having a substituent such as alkyl group one or more or one or more. Among these substituents, a hydroxyl group, a carboxyl group, a hydroxymethyl group, a cyano group, a cyanomethyl group and the like are preferable.
Examples of the linear or branched alkyl group having 1 to 4 carbon atoms for R ³ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group and a 2-methylpropyl group. Group, 1-methylpropyl group, t-butyl group and the like. Among these alkyl groups, a methyl group, an ethyl group, an n-propyl group, and an i-propyl group are preferred.

Preferred examples of the functional group side chain forming —C (R ³ ) ₃ in the formula (3) include 1-methyl-1-cyclopentyl, 1-ethyl-1-cyclopentyl, and 1-methyl-1. -Cyclohexyl group, 1-ethyl-1-cyclohexyl group, 2-methyladamantan-2-yl group, 2-methyl-3-hydroxyadamantan-2-yl group, 2-ethyltiladamantan-2-yl group, 2- An ethyl-3-hydroxyadamantan-2-yl group, a 2-n-propyladamantan-2-yl group, a 2-n-propyl-3-hydroxyadamantan-2-yl group, a 2-isopropyladamantan-2-yl group, 2-isopropyl-3-hydroxyadamantan-2-yl group, 2-methylbicyclo [2.2.1] hept-2-yl group, 2-ethylbicyclo [ .2.1] hept-2-yl group, 8-methyltricyclo [5.2.1.0 ^{2, 6]} dec-8-yl group, 8-ethyl-tricyclo [5.2.1.0 ^{2 , 6} ] dec-8-yl group, 4-methyl-tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodec-4-yl group, 4-ethyl-tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodec-4-yl group, 1- (bicyclo [2.2.1] hept-2-yl) -1-methylethyl group, 1- (tricyclo [5.2.1.0 ^{2, 6]} dec-8-yl) -1-methylethyl group, 1- (tetracyclo [6.2.1.1 ^3,6 .0 ^2,7] dec-4-yl) -1-methylethyl group, 1 -(Adamantan-1-yl) -1-methylethyl group, 1- (3-hydroxyadamantan-1-yl) -1-methylethyl group, 1,1-dicyclohexylethyl group, 1,1-di (bicyclo [ 2.2.1] Hept-2-yl) ethyl group, 1,1-di (tricyclo [5.2.1.0 ^2,6 ] dec-8-yl) ethyl group, 1,1-di (tetracyclo [6.2.1.1 ^3,6 .0 ^2,7] dodeca-4-yl) ethyl group, 1,1-di (adamantan-1-yl) ethyl group, And the like.

Preferred examples of the monomer that generates the repeating unit represented by the formula (3) that forms the polymer main chain are shown below.
1-methyl-1-cyclopentyl (meth) acrylate, 1-ethyl-1-cyclopentyl (meth) acrylate, 1-methyl-1-cyclohexyl (meth) acrylate, 1-ethyl (meth) acrylate -1-cyclohexyl ester, 2-methyladamantan-2-yl (meth) acrylate, 2-methyl3-hydroxyadamantan-2-yl (meth) acrylate, 2-ethyladamantane-2 (meth) acrylate -Yl ester, 2-ethyl 3-hydroxyadamantan-2-yl (meth) acrylate, 2-n-propyl-adamantan-2-yl (meth) acrylate, 2-n-propyl (meth) acrylate 3-hydroxyadamantan-2-yl ester, (meth) acrylic acid -Isopropyladamantan-2-yl ester, 2-isopropyl-3-hydroxyadamantan-2-yl (meth) acrylate, 2-methyladamantan-2-yl (meth) acrylate, 2-methyl (meth) acrylate Bicyclo [2.2.1] hept-2-yl ester, 2-ethyl (meth) acrylatebicyclo [2.2.1] hept-2-yl ester, 8-methyltricyclo [5 (meth) acrylate 2.2.1.0 ^2,6 ] dec-8-yl ester, 8-ethyltricyclo [5.2.1.0 ^2,6 ] deca-8-yl (meth) acrylate, (meth) acrylic acid 4-Methyltetracyclo acid [6.2.1.1 ^3,6 . 0 ^2,7 ] dodec-4-yl ester, 4-ethyltetracyclo (meth) acrylate [6.2.1.1 ^3,6 . 0 ^2,7 ] dodec-4-yl ester, (meth) acrylic acid 1- (bicyclo [2.2.1] hept-2-yl) -1-methyl ester, (meth) acrylic acid 1- (tricyclo [ 5.2.1.0 ^{2, 6]} dec-8-yl) -1-methyl ester, (meth) acrylic acid 1- (tetracyclo [6.2.1.1 ^3,6 .0 ^2,7] dodeca -4-yl) -1-methylethyl ester, 1- (adamantan-1-yl) -1-methylethyl (meth) acrylate, 1- (3-hydroxyadamantan-1-yl) (meth) acrylate -1-methylethyl ester, 1,1-dicyclohexylethyl (meth) acrylate, 1,1-di (bicyclo [2.2.1] hept-2-yl) ethyl (meth) acrylate, (meth) acrylate ) 1,1-di (acrylic acid) Cyclo [5.2.1.0 ^{2, 6]} dec-8-yl) ethyl ester, (meth) acrylic acid 1,1-di (tetracyclo [6.2.1.1 ^3,6 .0 ^2,7 ] Dodec-4-yl) ethyl ester and (meth) acrylic acid 1,1-di (adamantan-1-yl) ethyl ester.

  Among the monomers that produce the repeating unit represented by the formula (3) that forms the polymer main chain, particularly preferred monomers include 1-methyl-1-cyclopentyl (meth) acrylate. 1-ethyl-1-cyclopentyl (meth) acrylate, 1-methyl-1-cyclohexyl (meth) acrylate, 1-ethyl-1-cyclohexyl (meth) acrylate, 2- (meth) acrylate Methyl adamantane-2-yl ester, 2-ethyl adamantan-2-yl (meth) acrylate, 2-n-probyl adamantan-2-yl (meth) acrylate, 2-isopropyl (meth) acrylate Adamantane-2-yl ester, 1- (adamantan-1-yl) -1-methylethyl (meth) acrylate is It is below. These can be used alone or in combination.

The (meth) acrylic polymer of the present invention comprises a monomer represented by the following formula (4-1) and a (meth) acrylic acid-monomer as a monomer that generates a repeating unit forming a polymer main chain. 4-oxo-adamantan-1-yl ester, 2- (meth) acryloyloxy-5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonane, 2- (meth) acryloyloxy- 9-methoxycarbonyl-5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonane, 4- (meth) acryloyloxy-7-oxo-6-oxabicyclo [3.2.1] Octane, 4- (meth) acryloyloxy-2-methoxycarbonyl-7-oxo-6-oxabicyclo [3.2.1] octane, 8 (9)-(meth) acryloyloxy-3-oxo-4- Oxatricik B [5.2.1.0 ^2,6 ] decane or 5- (1,1,1 trifluoro-2-trifluoromethyl-2-hydroxypropyl) -norbornen-2-yl (meth) acrylate (Hereinafter, these monomers are collectively referred to as “(IV) monomer”).

式（４−１）において、Ｒは水素原子またはメチル基を表し、Ｘは単結合または炭素数１〜３の２価の有機基を表し、Ｙは相互に独立に単結合または炭素数１〜３の２価の有機基を表し、Ｒ⁴は相互に独立に水素原子、水酸基、シアノ基、または−ＣＯＯＲ⁵基を表し、Ｒ⁵が水素原子あるいは炭素数１〜４の直鎖状もしくは分岐状のアルキル基、または炭素数３〜２０の脂環式のアルキル基を表す。
式（４−１）におけるＸおよびＹで表される炭素数１〜３の２価の有機基としては、メチレン基、エチレン基、プロピレン基が挙げられる。
Ｒ⁵における、炭素数１〜４の直鎖状もしくは分岐状のアルキル基としては、メチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基、ｎ−ブチル基、２−メチルプロピル基、１−メチルプロピル基、ｔ−ブチル基を例示できる。
また、上記炭素数３〜２０の脂環式のアルキル基としては、−Ｃ_ｎＨ_２ｎ−１（ｎは３〜２０の整数）で表されるシクロアルキル基、例えば、シクロプロピル基、シクロブチル基、シクロペンチル基、シクロヘキシル基、シクロヘプチル基、シクロオクチル基等が、また、多環型脂環式アルキル基、例えばビシクロ［２．２．１］ヘプチル基、トリシクロ［５．２．１．０^2,6］デシル基、テトラシクロ［６．２．１^3,6．０^2,7］ドデカニル基、アダマンチル基等、または、直鎖状、分岐状または環状のアルキル基の１種以上あるいは１個以上でシクロアルキル基または多環型脂環式アルキル基の一部を置換した基等が挙げられる。
式（４−１）において、３つのＲ⁴のうち少なくとも１つは水酸基、シアノ基または−ＣＯＯＲ⁵基であるのが好ましい。また、式（４−１）において、Ｘが単結合のときは、３つのＹのうち少なくとも１つは炭素数１〜３の２価の有機基であり、かつ、３つのＲ⁴のうち少なくとも１つは水酸基、シアノ基または−ＣＯＯＲ⁵基であることが好ましい。

In the formula (4-1), R represents a hydrogen atom or a methyl group, X represents a single bond or a divalent organic group having 1 to 3 carbon atoms, and Y is independently a single bond or 1 to 3 carbon atoms. 3 represents a divalent organic group, R ⁴ independently represents a hydrogen atom, a hydroxyl group, a cyano group, or a —COOR ⁵ group; and R ⁵ represents a hydrogen atom or a linear or branched C 1-4 carbon atom. Represents an alicyclic alkyl group or an alicyclic alkyl group having 3 to 20 carbon atoms.
Examples of the divalent organic group having 1 to 3 carbon atoms represented by X and Y in Formula (4-1) include a methylene group, an ethylene group, and a propylene group.
Examples of the linear or branched alkyl group having 1 to 4 carbon atoms for R ⁵ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, -Methylpropyl group and t-butyl group.
Examples of the alicyclic alkyl groups of said 3 to 20 carbon _atoms, -C _{n H 2n-1} cycloalkyl group (n is an integer of 3 to 20) represented by, for example, cyclopropyl group, cyclobutyl group , A cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group and the like, and a polycyclic alicyclic alkyl group such as a bicyclo [2.2.1] heptyl group, a tricyclo [5.2.1.0 ^{2 , 6} ] decyl group, tetracyclo [6.2.1 ^3,6 . 0 ^2,7 ] dodecanyl group, adamantyl group, etc., or one or more linear, branched or cyclic alkyl groups or a part of a cycloalkyl group or a polycyclic alicyclic alkyl group. Substituted groups and the like can be mentioned.
In the formula (4-1), at least one of the three R ⁴ is preferably a hydroxyl group, a cyano group or a —COOR ⁵ group. In the formula (4-1), when X is a single bond, at least one of the three Ys is a divalent organic group having 1 to 3 carbon atoms, and at least one of the three R ⁴ . One is preferably a hydroxyl group, a cyano group or a —COOR ⁵ group.

Preferred monomers among the monomers represented by the formula (4-1) are shown below.
3-Hydroxyadamantan-1-yl (meth) acrylate, 3,5-dihydroxyadamantan-1-yl (meth) acrylate, 3-hydroxy-5-cyanoadamantan-1-yl (meth) acrylate 3-hydroxy-5-carboxyl adamantane-1-yl (meth) acrylate, 3-hydroxy-5-methoxycarbonyl adamantane-1-yl (meth) acrylate, 3-hydroxymethyl adamantane (meth) acrylate -1-yl ester, (meth) acrylic acid 3,5-dihydroxymethyladamantan-1-yl ester, (meth) acrylic acid 3-hydroxy-5-hydroxymethyladamantan-1-yl ester, (meth) acrylic acid 3 -Cyano-5-hydroxymethylada Tan-1-yl ester, 3-hydroxymethyl-5-carboxyladamantan-1-yl (meth) acrylate, 3-hydroxymethyl-5-methoxycarbonyladamantan-1-yl (meth) acrylate, (meth) acrylate ) Acrylic acid 3-cyanoadamantan-1-yl ester, (meth) acrylic acid 3,5-dicyanoadamantan-1-yl ester, (meth) acrylic acid 3-cyano-5-carboxyladamantan-1-yl ester, (Meth) acrylic acid 3-cyano-5-methoxycarbonyladamantan-1-yl ester, (meth) acrylic acid 3-carboxyladamantan-1-yl ester, (meth) acrylic acid 3,5-dicarboxyladamantan-1-yl Ester, 3- (meth) acrylic acid -5-methoxycarbonyl-adamantan-1-yl ester, (meth) acrylic acid 3-methoxycarbonyl 1-yl ester, (meth) acrylic acid 3,5-dimethoxy carbonyl 1-yl ester,

(Meth) acrylic acid 3-hydroxy-5-methyladamantan-1-yl ester, (meth) acrylic acid 3,5-dihydroxy-7-methyladamantan-1-yl ester, (meth) acrylic acid 3-hydroxy-5 -Cyano-7-methyladamantan-1-yl ester, (meth) acrylic acid 3-hydroxy-5-carboxyl-7-methyladamantan-1-yl ester, (meth) acrylic acid 3-hydroxy-5-methoxycarbonyl- 7-methyladamantan-1-yl ester, 3-hydroxymethyl-5-methyladamantan-1-yl (meth) acrylate, 3,5-dihydroxymethyl-7-methyladamantan-1-yl (meth) acrylate Ester, 3-hydroxy-5-hydroxymethyl (meth) acrylate- -Methyladamantan-1-yl ester, 3-cyano-5-hydroxymethyl-7-methyladamantan-1-yl (meth) acrylate, 3-hydroxymethyl-5-carboxyl-7-methyl (meth) acrylate Adamantane-1-yl ester, 3-hydroxymethyl-5-methoxycarbonyl-7-methyladamantan-1-yl (meth) acrylate, 3-cyano-5-methyladamantan-1-yl (meth) acrylate 3,5-dicyano-7-methyladamantan-1-yl (meth) acrylate, 3-cyano-5-carboxyl-7-methyladamantan-1-yl (meth) acrylate, (meth) acrylic acid 3-cyano-5-methoxycarbonyl-7-methyladamantan-1-i Ester, (meth) acrylic acid 3-carboxyl-5-methyladamantan-1-yl ester, (meth) acrylic acid 3,5-dicarboxyl-7-methyladamantan-1-yl ester, (meth) acrylic acid 3- Carboxyl-5-methoxycarbonyl-7-methyladamantan-1-yl ester, (meth) acrylic acid 3-methoxycarbonyl-5-methyladamantan-1-yl ester, (meth) acrylic acid 3,5-dimethoxycarbonyl-7 -Methyl adamantane-1-yl ester,

  3-hydroxy-5,7-dimethyladamantan-1-yl (meth) acrylate, 3-hydroxymethyl-5,7-dimethyladamantan-1-yl (meth) acrylate, 3- (meth) acrylate Cyano-5,7-dimethyladamantan-1-yl ester, 3-carboxyl-5- (meth) acrylic acid-5,7-dimethyladamantan-1-yl ester, 3-methoxycarbonyl-5,7-dimethyl (meth) acrylate Adamantane-1-yl ester and the like can be mentioned.

  Among the monomers represented by the formula (4-1), particularly preferable monomers include (meth) acrylic acid 3-hydroxyadamantan-1-yl ester and (meth) acrylic acid 3,5-dihydroxyadamantane -1-yl ester, 3-cyanoadamantan-1-yl (meth) acrylate, 3-carboxyladamantan-1-yl (meth) acrylate, 3-hydroxy-5-methyladamantane (meth) acrylate 1-yl ester, (meth) acrylic acid 3,5-dihydroxy-7-methyladamantan-1-yl ester, (meth) acrylic acid 3-hydroxy-5,7-dimethyladamantan-1-yl ester, (meth) Acrylic acid 3-carboxyl-5,7-dimethyladamantan-1-yl ester and the like can be mentioned.

  The (meth) acrylic polymer of the present invention further comprises a monomer that produces the above formula (1-1), the above formula (2-1), the above formula (3) or the above (IV) monomer. Other monomers can be included. Examples of other monomers include (meth) acrylic esters having no bridged hydrocarbon skeleton, such as (meth) acrylic acid, methyl (meth) acrylate, and ethyl (meth) acrylate, and (meth) acrylates. ) (Meth) acrylic esters having a bridged hydrocarbon skeleton such as norbornyl acrylate and isonorbornyl (meth) acrylate, unsaturated nitrile compounds such as (meth) acrylonitrile, (meth) acrylamide, N, N-dimethyl Unsaturated amide compounds such as (meth) acrylamide, other nitrogen-containing compounds such as N- (meth) acryloylmorpholine, N-vinylpyrrolidone, vinylpyridine, vinylimidazole, α- (meth) acryloyloxy-γ-butyrolactone, β -(Meth) acryloyloxy-γ-butyrolactone, α- (meth) acryloyloxy Such as -β, β-dimethyl-γ-butyrolactone, δ- (meth) acryloyloxy-β, β-dimethyl-γ-valerolactone, and β- (meth) acryloyloxy-β-methyl-δ-valerolactone; ) Monofunctional monomers such as acryloyloxylactone compounds.

The (meth) acrylic polymer of the present invention is a copolymer containing a monomer represented by the formula (1-1) and / or the formula (2-1), and preferably the formula (1-1) And / or a copolymer containing at least a monomer represented by the formula (2-1) and a monomer generating a repeating unit represented by the formula (3), and more preferably a copolymer represented by the formula (1) -1) and / or a copolymer containing at least a monomer represented by the formula (2-1), a monomer represented by the formula (3), and a (IV) monomer.
The proportion of the copolymer is such that the monomer represented by the formula (1-1) and / or the formula (2-1) is 20 to 70 mol%, preferably 30 to 60 mol%, based on the whole copolymer. Mol%. If the amount is less than 20 mol%, the developability as a resist tends to decrease, and if it exceeds 70 mol%, the resolution tends to deteriorate and the solubility in a resist solvent tends to decrease.
When it contains a monomer that produces a repeating unit represented by the formula (3), the amount is 20 to 75 mol%, preferably 30 to 70 mol%, based on the whole copolymer. If the amount is less than 20 mol%, the resolution tends to deteriorate, and if it exceeds 75 mol%, the developability tends to decrease and a pattern tends not to be obtained.
(IV) When a monomer is contained, its compounding ratio is 5 to 55 mol%, preferably 8 to 55 mol%, based on the whole copolymer. When the amount is less than 5 mol%, the resolution as a resist tends to deteriorate, and when the amount exceeds 55 mol%, the developability as a resist tends to decrease.

The (meth) acrylic polymer is obtained by, for example, using a mixture of monomers corresponding to each repeating unit with a radical polymerization initiator such as hydroperoxides, dialkyl peroxides, diacyl peroxides, and azo compounds. It can be produced by polymerizing in an appropriate solvent in the presence of a chain transfer agent if necessary.
Examples of the solvent used in the polymerization include cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane; ethyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate, propylene glycol monomethyl ether Saturated carboxylic acid esters such as acetate; alkyl lactones such as γ-butyrolactone; alkyl ketones such as 2-butanone, 2-heptanone and methyl isobutyl ketone; cycloalkyl ketones such as cyclohexanone; 2-propanol and propylene glycol monomethyl Examples include alcohols such as ether.
These solvents can be used alone or in combination of two or more.
The reaction temperature in the above polymerization is usually 40 to 120 ° C, preferably 50 to 100 ° C, and the reaction time is usually 1 to 48 hours, preferably 1 to 24 hours.

The (meth) acrylic polymer of the present invention naturally has a small amount of impurities such as halogens and metals, and the residual monomer and oligomer components are below a predetermined value, for example, 0.1% by weight by HPLC. It is preferable to obtain a radiation-sensitive composition which can not only further improve the sensitivity, resolution, process stability, pattern shape, and the like as a resist but also can be used as a resist that does not change with time due to foreign substances in liquid or sensitivity. Can be
Examples of the method for purifying the (meth) acrylic polymer include the following methods. As a method for removing impurities such as metals, a method of adsorbing metals in a resin solution using a zeta potential filter or removing the metals in a chelated state by washing the resin solution with an acidic aqueous solution such as oxalic acid or sulfonic acid And the like. In addition, as a method of removing the residual monomer or oligomer component to a specified value or less, a liquid-liquid extraction method of removing the residual monomer or oligomer component by washing with water or combining an appropriate solvent, a method of a specific molecular weight or less. A purification method in a solution state such as ultrafiltration for extracting and removing only a monomer, and a residual monomer etc. by coagulating the polymer in a poor solvent by dropping a (meth) acrylic polymer solution into a poor solvent. And a purification method in a solid state such as washing the polymer slurry filtered off with a poor solvent. Also, these methods can be combined. The poor solvent used in the above-mentioned reprecipitation method depends on the physical properties of the (meth) acrylic polymer to be purified and cannot be unequivocally exemplified. The poor solvent is appropriately selected.

The weight average molecular weight (hereinafter abbreviated as “Mw”) of the (meth) acrylic polymer in terms of polystyrene measured by gel permeation chromatography (GPC) is generally 1,000 to 300,000, preferably 2,000 to 200. And more preferably from 3,000 to 100,000. In this case, if the Mw of the (meth) acrylic polymer is less than 1,000, the heat resistance as a resist tends to decrease, while if it exceeds 300,000, the developability as a resist tends to decrease. .
The ratio (Mw / Mn) of the Mw of the (meth) acrylic polymer to the number average molecular weight in terms of polystyrene by gel permeation chromatography (GPC) (hereinafter abbreviated as “Mn”) is usually 1 to 5 , Preferably 1-3.

In the present invention, the (meth) acrylic polymer can be used alone or in combination of two or more.
The (meth) acrylic polymer is insoluble in alkali or hardly soluble in alkali, but becomes easily soluble in alkali by the action of an acid. Therefore, it is suitable as an acid-dissociable group-containing resin used in the radiation-sensitive resin composition.
The (meth) acrylic polymer containing a repeating unit represented by the formula (1) and / or the formula (2) is a repeating unit containing an acid dissociable group, for example, represented by the formula (3). Including repeat units.

A radiation-sensitive resin composition can be obtained by using the (meth) acrylic polymer as an acid-dissociable group-containing resin and combining it with an acid generator, which is a component that generates an acid upon irradiation with radiation.
Examples of the acid generator include onium salts such as sulfonium salts and iodonium salts, organic halogen compounds, and sulfone compounds such as disulfones and diazomethane sulfones.
Preferred examples of the acid generator include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, and triphenylsulfonium 2-bicyclo [2.2.1]. ] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2- (3-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] dodecanyl) -1 , 1-difluoroethanesulfonate, triphenylsulfonium N, N'-bis (nonafluoro-n-butanesulfonyl) imidate, triphenylsulfonium camphorsulfonate and other triphenylsulfonium salt compounds;

4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2. 2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexyl-phenyl diphenyl sulfonium 2- (3-tetracyclo [4.4.0.1 ^2,5 .1 ^{7, 10} ] dodecanyl) -1,1-difluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium N, N'-bis (nonafluoro-n-butanesulfonyl) imidate, 4-cyclo 4-cyclohexylphenyldiphenylsulfonium salt compounds such as hexylphenyldiphenylsulfonium camphorsulfonate;

4-tert-butylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-tert-butylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-tert-butylphenyl Diphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-t-butylphenyldiphenylsulfonium 2- (3-tetracyclo [4.4. 0.1 ^2,5 .1 ^7,10 ] dodecanyl) -1,1-difluoroethanesulfonate, 4-t-butylphenyldiphenylsulfonium N, N'-bis (nonafluoro-n-butanesulfonyl) imidate, 4-t- Butylphenyldiphenyls 4-t-butylphenyldiphenylsulfonium salt compound such as ruphonium camphorsulfonate;

Tri (4-t-butylphenyl) sulfonium trifluoromethanesulfonate, tri (4-t-butylphenyl) sulfonium nonafluoro-n-butanesulfonate, tri (4-t-butylphenyl) sulfonium perfluoro-n-octanesulfonate, Tri (4-t-butylphenyl) sulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, tri (4-t-butylphenyl) sulfonium 2 - (3-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanyl) -1,1-difluoroethanesulfonate, tri (4-t- butylphenyl) sulfonium N, N'-bis (nonafluoro -N-butanesulfonyl) imidate, tri (4-t-butylphenyl) sulfonium can Tri (4-t-butylphenyl) sulfonium salt compound such as fursulfonate;

Diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2 2-tetrafluoroethane sulfonate, diphenyliodonium 2- (3-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanyl) -1,1-difluoroethanesulfonate, diphenyliodonium N, N'-bis Diphenyliodonium salt compounds such as (nonafluoro-n-butanesulfonyl) imidate and 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 [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium 2 - (3-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanyl) -1,1-difluoroethanesulfonate, bis (4-t- butylphenyl) iodonium N, N'-bis (nonafluoro -N-butanesulfonyl) imidate, bis (4-t-butylphenyl) iodonium can Bis (4-t-butylphenyl) iodonium salt compound such as fursulfonate;

1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiopheniumnonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium 2-bicyclo [2.2. 1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium 2- (3-tetracyclo [4.4. 0.1 ^2,5 .1 ^7,10] dodecanyl) -1,1-difluoroethanesulfonate, 1- (4- -Butoxynaphthalen-1-yl) tetrahydrothiophenium N, N'-bis (nonafluoro-n-butanesulfonyl) imidate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium camphorsulfonate, etc. 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium salt compound;

1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, (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 2- (3-tetracyclo [4.4. 0.1 ^2,5 .1 ^7,10] dodecanyl) -1,1-difluoroethanesulfinate , 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium N, N′-bis (nonafluoro-n-butanesulfonyl) imidate, 1- (3,5-dimethyl-4-hydroxyphenyl) 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium salt compound such as tetrahydrothiophenium camphorsulfonate;

N- (trifluoromethanesulfonyloxy) succinimide, N- (nonafluoro-n-butanesulfonyloxy) succinimide, N- (perfluoro-n-octanesulfonyloxy) succinimide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethane sulfonyloxy) succinimide, N- (2- (3- tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanyl) Succinimide compounds such as -1,1-difluoroethanesulfonyloxy) succinimide and N- (camphorsulfonyloxy) succinimide;

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-dicarboxy imide, N- (2- (3- tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanyl) -1,1-difluoroethane-sulfonyloxy) bicyclo [2.2.1] hept -5 −En Bicyclo [2.2.1] hept-5 such as 2,3-dicarboximide, N- (camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide Ene-2,3-dicarboximide compounds and the like.

  In the present invention, the acid generators can be used alone or in combination of two or more. The amount of the acid generator used is usually 0.1 to 30 parts by weight, preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the (meth) acrylic polymer, from the viewpoint of securing the sensitivity and developability as a resist. -20 parts by weight. In this case, if the amount of the acid generator used is less than 0.1 part by weight, the sensitivity and developability tend to decrease, while if it exceeds 30 parts by weight, the transparency to radiation decreases and the rectangular resist pattern is reduced. Tends to be difficult to obtain.

In the radiation-sensitive resin composition of the present invention, if necessary, an acid diffusion controller, an alicyclic additive having an acid-dissociable group, an alicyclic additive having no acid-dissociable group, a surfactant And various additives such as sensitizers.
The acid diffusion controller is a component having a function of controlling a diffusion phenomenon of an acid generated from an acid generator by irradiation in a resist film and suppressing an undesirable chemical reaction in a non-irradiated region.
By blending such an acid diffusion controller, the storage stability of the resulting radiation-sensitive resin composition is improved, the resolution as a resist is further improved, and the delay time from irradiation to development processing ( Variations in the line width of the resist pattern due to variations in PED) can be suppressed, and a composition with extremely excellent process stability can be obtained.
As the acid diffusion controlling agent, a nitrogen-containing organic compound whose basicity does not change by irradiation or heat treatment during the resist pattern forming step is preferable.

Examples of such nitrogen-containing organic compounds include “tertiary amine compounds”, “amide group-containing compounds”, “quaternary ammonium hydroxide compounds”, and “nitrogen-containing heterocyclic compounds”.
Examples of the “tertiary amine compound” include, for example, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n Tri (cyclo) alkylamines such as -octylamine, tri-n-nonylamine, tri-n-decylamine, cyclohexyldimethylamine, dicyclohexylmethylamine and tricyclohexylamine; aniline, N-methylaniline, N, N-dimethylaniline Aromatic amines such as, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, 2,6-dimethylaniline, 2,6-diisopropylaniline, diphenylamine, triphenylamine and naphthylamine; Ethanolamine, Alkanolamines such as ethanolaniline; N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- ( 4-aminophenyl) -1-methylethyl] benzenetetramethylenediamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2- (4-hydroxyphenyl) propane, 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene, bis (2-dimethylamino) Chill) ether, bis (2-diethylaminoethyl) ether.

  As the "amide group-containing compound", for example, Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, N- t-butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine, N, N -Di-t-butoxycarbonyl-1-adamantylamine, N, N-di-tert-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4'-diaminodiphenylmethane, N, N'-di-t-butoxycarbonylhexamethylenediamine, N, N, ', N'-tetra-t-butoxycarbonylhexamethylenediamine, N, N'-di-t-butoxycarbonyl-1,7-diaminoheptane, N, N'-di-t-butoxycarbonyl-1,8- Diaminooctane, N, N'-di-tert-butoxycarbonyl-1,9-diaminononane, N, N'-di-tert-butoxycarbonyl-1,10-diaminodecane, N, N'-di-tert-butoxy Carbonyl-1,12-diaminododecane, N, N′-di-tert-butoxycarbonyl-4,4′-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole , Nt-butoxycarbonyl-2-phenylbenzimidazole, Nt-butoxycarbonyl-pyrrolidine, Nt-butoxy Nt-butoxycarbonyl group-containing amino compounds such as carbonyl-4-hydroxy-1-piperidine and Nt-butoxycarbonyl-morpholine, as well as formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N -Methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine, N-acetyl-2-adamantylamine and the like.

Examples of the “quaternary ammonium hydroxide compound” include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylammonium hydroxide, tetra-n-butylammonium hydroxide and the like.
Examples of the “nitrogen-containing heterocyclic compound” include, for example, imidazoles such as imidazole, 4-methylimidazole, 1-benzyl-2-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole and 2-phenylbenzimidazole; Pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, Pyridines such as quinoline, 4-hydroxyquinoline, 8-oxyquinoline and acridine; piperazines such as piperazine and 1- (2-hydroxyethyl) piperazine; and pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, 3 Piperidino-1,2-propanediol, morpholine, 4-methylmorpholine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane.

  Among the above nitrogen-containing heterocyclic compounds, tertiary amine compounds, amide group-containing compounds, and nitrogen-containing heterocyclic compounds are preferable, and among the amide group-containing compounds, Nt-butoxycarbonyl group-containing amino compounds are preferable. Among nitrogen heterocyclic compounds, imidazoles are preferred.

  The acid diffusion controllers can be used alone or in combination of two or more. The amount of the acid diffusion controller is usually 15 parts by weight or less, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, based on 100 parts by weight of the (meth) acrylic polymer. In this case, if the amount of the acid diffusion controller exceeds 15 parts by weight, the sensitivity as a resist and the developability of a radiation-irradiated portion tend to decrease. If the amount of the acid diffusion controller is less than 0.001 part by weight, the pattern shape and dimensional fidelity as a resist may be reduced depending on the process conditions.

In addition, an alicyclic additive having an acid-dissociable group or an alicyclic additive having no acid-dissociable group is a component having an effect of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. It is.
Examples of such alicyclic additives include t-butyl 1-adamantanecarboxylate, t-butoxycarbonylmethyl 1-adamantanecarboxylate, α-butyrolactone 1-adamantanecarboxylate, and 1,3-adamantanedicarboxylate. -T-butyl, t-butyl 1-adamantane acetate, t-butoxycarbonylmethyl 1-adamantane acetate, di-t-butyl 1,3-adamantanediacetate, 2,5-dimethyl-2,5-di (adamantylcarbonyl Adamantane derivatives such as oxy) hexane; t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholate, 2-ethoxyethyl deoxycholate, 2-cyclohexyloxyethyl deoxycholate, 3-oxocyclohexyl deoxycholate; Deoxycol Deoxycholates such as tetrahydropyranyl and mevalonolactone deoxycholate; t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid, 2-cyclohexyloxyethyl lithocholic acid, lithocholic acid Lithocholates such as 3-oxocyclohexyl, tetrahydropyranyl lithocholic acid, mevalonolactone lithocholic acid; dimethyl adipate, diethyl adipate, dipropyl adipate, di-n-butyl adipate, di-t-butyl adipate and the like And the like.
These alicyclic additives can be used alone or in combination of two or more. The amount of the alicyclic additive is usually 50 parts by weight or less, preferably 30 parts by weight or less, based on 100 parts by weight of the (meth) acrylic polymer. In this case, if the amount of the alicyclic additive exceeds 50 parts by weight, the heat resistance of the resist tends to decrease.

Further, a surfactant as an additive is a component having an effect of improving coatability, striation, developability, and the like.
Examples of such a surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, and polyethylene glycol dilaurate. In addition to nonionic surfactants such as polyethylene glycol distearate, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.) and Polyflow No. No. 75, the same No. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, and EF352 (manufactured by Tochem Products), Megafax F171 and F173 (manufactured by Dainippon Ink and Chemicals, Inc.), Florard FC430, FC431 (manufactured by Sumitomo 3M Limited), Asahigard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 ( (Made by Asahi Glass Co., Ltd.).
These surfactants can be used alone or in combination of two or more. The amount of the surfactant is usually 2 parts by weight or less based on 100 parts by weight of the (meth) acrylic polymer.

The sensitizer as an additive absorbs radiation energy and transmits the energy to an acid generator, thereby exhibiting an action of increasing the amount of acid generated. It has the effect of improving the apparent sensitivity.
Examples of such a sensitizer include carbazoles, benzophenones, rose bengals, anthracenes, phenols, and the like.
These sensitizers can be used alone or in combination of two or more. The compounding amount of the sensitizer is preferably 50 parts by weight or less based on 100 parts by weight of the (meth) acrylic polymer.
Further, additives other than the above include an antihalation agent, an adhesion aid, a storage stabilizer, and an antifoaming agent.

The radiation-sensitive resin composition of the present invention is usually dissolved in a solvent so that the total solid content concentration is usually 3 to 50% by weight, preferably 5 to 25% by weight when used. The solution is filtered through a filter having a pore size of about 0.2 μm to prepare a composition solution.
Examples of the solvent used for preparing the composition solution include linear or branched ketones such as 2-pentanone, 2-hexanone, 2-heptanone and 2-octanone; and cyclopentanone and cyclohexanone. Cyclic ketones; propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate; alkyl 2-hydroxypropionates such as methyl 2-hydroxypropionate and ethyl 2-hydroxypropionate; In addition to alkyl 3-alkoxypropionates such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-ethoxypropionate,

  Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, n-butyl acetate, methyl pyruvate , Ethyl pyruvate, N-methylpyrrolidone, γ-butyrolactone and the like.

  These solvents can be used alone or as a mixture of two or more. Propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, 2-heptanone, cyclohexanone, γ-butyrolactone, ethyl 2-hydroxypropionate, 3-ethoxy It is preferable to contain at least one selected from ethyl propionate.

The radiation-sensitive resin composition of the present invention is particularly useful as a chemically amplified resist. In particular, it is useful as a resist capable of reducing the line edge roughness of a pattern after development.
In chemically amplified resists, the acid dissociable groups in the resin are dissociated by the action of the acid generated from the acid generator by irradiation, resulting in the formation of a carboxyl group. The solubility is increased, and the irradiated portion is dissolved and removed by an alkali developer to obtain a positive resist pattern.
When forming a resist pattern from the radiation-sensitive resin composition of the present invention, the composition solution is coated with an appropriate coating means such as spin coating, casting coating, roll coating, for example, a silicon wafer, coated with aluminum. A resist film is formed by applying it on a substrate such as a wafer which has been subjected to a heat treatment (hereinafter referred to as “PB”) in some cases, and then the resist film is formed so as to form a predetermined resist pattern. Irradiate. The radiation used at that time is, for example, ultraviolet light, KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), EUV (extreme ultraviolet light, wavelength 13 nm, etc.). Far-ultraviolet rays, charged particle beams such as electron beams, X-rays such as synchrotron radiation and the like can be appropriately selected and used. Of these, far-ultraviolet rays and electron beams are preferable. The irradiation conditions such as the irradiation amount are appropriately selected depending on the composition of the radiation-sensitive resin composition, the type of each additive, and the like.
In the present invention, in order to stably form a high-precision fine pattern, it is preferable to perform a heat treatment (hereinafter, referred to as “PEB”) after the irradiation. By this PEB, the dissociation reaction of the acid-dissociable organic group in the (meth) acrylic polymer proceeds smoothly. The heating conditions for PEB vary depending on the composition of the radiation-sensitive resin composition, but are usually 30 to 200 ° C, preferably 50 to 170 ° C.

In the present invention, in order to maximize the potential of the radiation-sensitive resin composition, as disclosed in, for example, Japanese Patent Publication No. 6-12452, an organic or inorganic resin is used on a substrate to be used. An anti-reflection film may be formed, and in order to prevent the influence of basic impurities and the like contained in the environmental atmosphere, a resist coating may be formed on the resist film as disclosed in, for example, JP-A-5-188598. Can be provided with a protective film, or these techniques can be used in combination.
Next, a predetermined resist pattern is formed by developing the irradiated resist film using an alkaline developer.
As the alkali developer, for example, an alkaline aqueous solution in which tetramethylammonium hydroxide is dissolved is preferable.
The concentration of the alkaline aqueous solution is usually 10% by weight or less. In this case, if the concentration of the alkaline aqueous solution exceeds 10% by weight, the non-irradiated portion may be dissolved in the developer, which is not preferable.
Further, an appropriate amount of a surfactant or the like can be added to the alkaline aqueous solution. After development with an alkali developing solution, it is generally washed with water and dried.

化合物（５−１）５０．５１ｇ（４５ｍｏｌ％）、化合物（５−２）１３．５０ｇ（１５ｍｏｌ％）、化合物（５−３）３５．９９ｇ（４０ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）３．７０ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌ の三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのメタノールへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのメタノールにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（７５ｇ、収率７５％）。この重合体はＭｗが１０,３００であり、¹³Ｃ−ＮＭＲ分析の結果、化合物（５−１）、化合物（５−２）、化合物（５−３）による繰り返し単位、各繰り返し単位の含有率が４７．６：１４．２：３８．２（ｍｏｌ％）の共重合体であった。この重合体を（メタ）アクリル系重合体（Ａ−１）とする。
本発明において、Ｍｗは東ソー（株）製ＧＰＣカラム（Ｇ２０００ＨＸＬ ２本、Ｇ３０００ＨＸＬ １本、Ｇ４０００ＨＸＬ １本）を用い、流量１．０ｍｌ ／分、溶出溶媒テトラヒドロフラン、カラム温度４０℃の分析条件で、単分散ポリスチレンを標準とするゲルパーミエーションクロマトグラフィ（ＧＰＣ）により測定した。 Example 1

50.51 g (45 mol%) of the compound (5-1), 13.50 g (15 mol%) of the compound (5-2), and 35.99 g (40 mol%) of the compound (5-3) were dissolved in 200 g of 2-butanone. Further, a monomer solution charged with 3.70 g of dimethyl 2,2′-azobis (2-methylpropionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of methanol, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of methanol on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powder polymer (75 g, yield: 75%). . This polymer has a Mw of 10,300. As a result of ¹³ C-NMR analysis, the repeating units of the compound (5-1), the compound (5-2), and the compound (5-3), and the content of each repeating unit Was a copolymer of 47.6: 14.2: 38.2 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-1).
In the present invention, Mw was measured using a GPC column (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation under the analysis conditions of a flow rate of 1.0 ml / min, an elution solvent of tetrahydrofuran, and a column temperature of 40 ° C. It was measured by gel permeation chromatography (GPC) using dispersed polystyrene as a standard.

化合物（６−１）４９．６４ｇ（４５ｍｏｌ％）、化合物（６−２）１３．２１ｇ（１５ｍｏｌ％）、化合物（６−３）３７．１５ｇ（４０ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）３．６１ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌの三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのイソプロピルアルコールへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのイソプロピルアルコールにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（７６ｇ、収率７６％）。この重合体はＭｗが８,２００であり、¹³Ｃ−ＮＭＲ分析の結果、化合物（６−１）、化合物（６−２）、化合物（６−３）による繰り返し単位、各繰り返し単位の含有率が４６．４：１５．５：３８．１（ｍｏｌ％）の共重合体であった。この重合体を（メタ）アクリル系重合体（Ａ−２）とする。 Example 2

Compound (6-1) 49.64 g (45 mol%), compound (6-2) 13.21 g (15 mol%), and compound (6-3) 37.15 g (40 mol%) were dissolved in 2-butanone 200 g, Further, a monomer solution charged with 3.61 g of dimethyl 2,2′-azobis (2-methylpropionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of isopropyl alcohol, and the precipitated white powder is filtered. The filtered white powder was washed twice with 400 g of isopropyl alcohol on the slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (76 g, yield 76%). ). This polymer had a Mw of 8,200. As a result of ¹³ C-NMR analysis, the repeating units of compound (6-1), compound (6-2) and compound (6-3), and the content of each repeating unit Was a copolymer of 46.4: 15.5: 38.1 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-2).

化合物（５−１）５６．１５ｇ（４５ｍｏｌ％）、化合物（５−２）１５．１３ｇ（１５ｍｏｌ％）、化合物（７−１）２８．７２ｇ（４０ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）３．５９ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌの三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのヘプタンへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのヘプタンにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（７７ｇ、収率７７％）。この重合体はＭｗが９,１００であり、¹³Ｃ−ＮＭＲ分析の結果、化合物（５−１）、化合物（５−２）、化合物（７−１）による繰り返し単位、各繰り返し単位の含有率が４８．６：１４．１：３７．３（ｍｏｌ％）の共重合体であった。この重合体を（メタ）アクリル系重合体（Ａ−３）とする。 Example 3

56.15 g (45 mol%) of the compound (5-1), 15.13 g (15 mol%) of the compound (5-2), and 28.72 g (40 mol%) of the compound (7-1) were dissolved in 200 g of 2-butanone. Further, a monomer solution charged with 3.59 g of dimethyl 2,2′-azobis (2-methylpropionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of heptane, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of heptane on the slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (77 g, yield 77%). . This polymer has a Mw of 9,100. As a result of ¹³ C-NMR analysis, the repeating units of the compound (5-1), the compound (5-2), and the compound (7-1), and the content of each repeating unit Was 48.6: 14.1: 37.3 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-3).

化合物（５−１）６０．６４ｇ（５５ｍｏｌ％）、化合物（８−１）３９．６０ｇ（４５ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）３．４６ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌの三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのメタノールへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのメタノールにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（７０ｇ、収率７０％）。この重合体はＭｗが９,８００であり、¹³Ｃ−ＮＭＲ分析の結果、化合物（５−１）、化合物（８−１）による繰り返し単位、各繰り返し単位の含有率が５８．８：４１．２（ｍｏｌ％）の共重合体であった。この重合体を（メタ）アクリル系重合体（Ａ−４）とする。 Example 4

60.64 g (55 mol%) of the compound (5-1) and 39.60 g (45 mol%) of the compound (8-1) were dissolved in 200 g of 2-butanone, and further dissolved in dimethyl 2,2′-azobis (2-methylpropionate). A monomer solution charged with 3.46 g) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of methanol, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of methanol on the slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (70 g, yield 70%). . This polymer had a Mw of 9,800. As a result of ¹³ C-NMR analysis, the repeating units of compound (5-1) and compound (8-1), and the content of each repeating unit was 58.8: 41. The copolymer was 2 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-4).

化合物（５−１）５４．９２ｇ（５０ｍｏｌ％）、化合物（９−１）２６．４１ｇ（３０ｍｏｌ％）、化合物（９−２）１８．６６ｇ（２０ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）３．４６ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌの三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのメタノールへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのメタノールにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（６８ｇ、収率６８％）。この重合体はＭｗが８,９００であり、¹³Ｃ−ＮＭＲ分析の結果、化合物（５−１）、化合物（９−１）、化合物（９−２）による繰り返し単位、各繰り返し単位の含有率が５５．８：２９．１：１５．１（ｍｏｌ％）の共重合体であった。この重合体を（メタ）アクリル系重合体（Ａ−５）とする。 Example 5

Compound (5-1) 54.92 g (50 mol%), compound (9-1) 26.41 g (30 mol%), and compound (9-2) 18.66 g (20 mol%) were dissolved in 2-butanone 200 g, Further, a monomer solution charged with 3.46 g of dimethyl 2,2′-azobis (2-methylpropionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of methanol, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of methanol on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powder polymer (68 g, yield 68%). . This polymer has a Mw of 8,900. As a result of ¹³ C-NMR analysis, the repeating units of the compound (5-1), the compound (9-1) and the compound (9-2), and the content of each repeating unit Was 55.8: 29.1: 15.1 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-5).

化合物（１０−１）５３．６９ｇ（５５ｍｏｌ％）と、化合物（５−３）４６．３１ｇ（４５ｍｏｌ％）とを２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）４．０４ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌの三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのメタノールへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのメタノールにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（６３ｇ、収率６３％）。この重合体はＭｗが９,７００であり、¹³Ｃ−ＮＭＲ分析の結果、化合物（１０−１）、化合物（５−３）による繰り返し単位、各繰り返し単位の含有率が５９．６：４０．４（ｍｏｌ％）の共重合体であった。この重合体を（メタ）アクリル系重合体（Ａ−６）とする。 Comparative Example 1

53.69 g (55 mol%) of the compound (10-1) and 46.31 g (45 mol%) of the compound (5-3) were dissolved in 200 g of 2-butanone, and further dissolved in dimethyl 2,2′-azobis (2-methyl). A monomer solution charged with 4.04 g of propionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of methanol, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of methanol on the slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (63 g, yield 63%). . This polymer had a Mw of 9,700. As a result of ¹³ C-NMR analysis, the repeating units of the compound (10-1) and the compound (5-3) had a content of 59.6: 40. The copolymer was 4 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-6).

化合物（５−１）３９．９９ｇ（５０ｍｏｌ％）、化合物（８−１）２０．３９ｇ（２０ｍｏｌ％）、化合物（１１−１）３９．６２ｇ（３０ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）６．００ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌ の三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのヘプタンヘ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのヘプタンにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（６０ｇ、収率６０％）。この重合体はＭｗが５，３００であり、化合物（５−１）、化合物（８−１）、化合物（１１−１）で表される繰り返し単位、各繰り返し単位の含有率が３５．８：１７．１：４７．０（ｍｏｌ％）の共重合体であった。この重合体を（メタ）アクリル系重合体（Ａ−７）とする。 Example 6

39.99 g (50 mol%) of the compound (5-1), 20.39 g (20 mol%) of the compound (8-1), and 39.62 g (30 mol%) of the compound (11-1) were dissolved in 200 g of 2-butanone. Further, a monomer solution charged with 6.00 g of dimethyl 2,2'-azobis (2-methylpropionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After the completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by cooling with water, poured into 2,000 g of heptane, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of heptane on the slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (60 g, yield 60%). . This polymer has a Mw of 5,300, and has a repeating unit represented by the compound (5-1), the compound (8-1) or the compound (11-1), and the content of each repeating unit is 35.8: 17.1: 47.0 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-7).

化合物（５−１）４０．８３ｇ（３０ｍｏｌ％）、化合物（１１−１）４４．４９ｇ（５５ｍｏｌ％）、化合物（１２−１）１４．６８ｇ（１５ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）６．１４ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌの三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのヘプタンへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのヘプタンにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（６９ｇ、収率６９％）。この重合体はＭｗが５，８００であり、化合物（５−１）、化合物（１１−１）、化合物（１２−１）で表される繰り返し単位、各繰り返し単位の含有率が３３．９：４９．２：１６．９（ｍｏｌ％）の共重合体であった。この重合体を（メタ）アクリル系重合体（Ａ−８）とする。 Example 7

40.83 g (30 mol%) of the compound (5-1), 44.49 g (55 mol%) of the compound (11-1), and 14.68 g (15 mol%) of the compound (12-1) were dissolved in 200 g of 2-butanone. Further, a monomer solution charged with 6.14 g of dimethyl 2,2′-azobis (2-methylpropionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of heptane, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of heptane on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powder polymer (69 g, yield 69%). . This polymer has a Mw of 5,800, and has a repeating unit represented by the compound (5-1), the compound (11-1) and the compound (12-1), and a content of each repeating unit of 33.9: 49.2: 16.9 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-8).

化合物（５−１）３６．０４ｇ（３０ｍｏｌ％）、化合物（１１−１）３５．７１ｇ（５０ｍｏｌ％）、化合物（１３−１）２８．２５ｇ（２０ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）３．５９ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌの三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのヘプタンへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのヘプタンにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（６９ｇ、収率６９％）。この重合体はＭｗが７，１００であり、化合物（５−１）、化合物（１１−１）、化合物（１３−１）で表される繰り返し単位、各繰り返し単位の含有率が３４．５：４７．１：１８．４（ｍｏｌ％）の共重合体であった。この重合体を(メタ)アクリル系重合体（Ａ−９）とする。 Example 8

36.04 g (30 mol%) of the compound (5-1), 35.71 g (50 mol%) of the compound (11-1) and 28.25 g (20 mol%) of the compound (13-1) were dissolved in 200 g of 2-butanone, Further, a monomer solution charged with 3.59 g of dimethyl 2,2′-azobis (2-methylpropionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of heptane, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of heptane on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powder polymer (69 g, yield 69%). . This polymer has Mw of 7,100, and has a repeating unit represented by compound (5-1), compound (11-1), and compound (13-1), and a content of each repeating unit of 34.5: 47.1: 18.4 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-9).

化合物（１４−１）４６．２８ｇ（３５ｍｏｌ％）、化合物（８−１）３２．２４ｇ（３５ｍｏｌ％）、化合物（１１−１）２１．４８ｇ（３０ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）５．４５ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌの三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのヘプタンへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのヘプタンにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（５５ｇ、収率５５％）。この重合体はＭｗが７，５００であり、化合物（１４−１）、化合物（８−１）、化合物（１１−１）で表される繰り返し単位、各繰り返し単位の含有率が３２．５：３５．２：３２．２（ｍｏｌ％）の共重合体であった。この重合体を(メタ)アクリル系重合体（Ａ−１０）とする。 Example 9

Compound (14-1) 46.28 g (35 mol%), compound (8-1) 32.24 g (35 mol%), and compound (11-1) 21.48 g (30 mol%) were dissolved in 2-butanone 200 g, Further, a monomer solution charged with 5.45 g of dimethyl 2,2′-azobis (2-methylpropionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of heptane, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of heptane on the slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (55 g, yield 55%). . This polymer has a Mw of 7,500, and has a repeating unit represented by the compound (14-1), the compound (8-1) or the compound (11-1), and a content of each repeating unit of 32.5: 35.2: 32.2 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-10).

化合物（１４−１）４３．６８ｇ（３５ｍｏｌ％）、化合物（１２−１）１３．６６ｇ（１５ｍｏｌ％）、化合物（１１−１）３７．６５ｇ（５０ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）３．５９ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌの三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのヘプタンへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのヘプタンにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（６０ｇ、収率６０％）。この重合体はＭｗが７，９００であり、化合物（１４−１）、化合物（１２−１）、化合物（１１−１）で表される繰り返し単位、各繰り返し単位の含有率が４９．３：１７．３：３３．４（ｍｏｌ％）の共重合体であった。この重合体を(メタ)アクリル系重合体（Ａ−１１）とする。 Example 10

43.68 g (35 mol%) of the compound (14-1), 13.66 g (15 mol%) of the compound (12-1), and 37.65 g (50 mol%) of the compound (11-1) were dissolved in 200 g of 2-butanone. Further, a monomer solution charged with 3.59 g of dimethyl 2,2′-azobis (2-methylpropionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of heptane, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of heptane on the slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (60 g, yield 60%). . This polymer has a Mw of 7,900, and has a repeating unit represented by the compound (14-1), the compound (12-1) and the compound (11-1), and a content of each repeating unit of 49.3: 17.3: 33.4 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-11).

化合物（５−１）１４．２８ｇ（１０ｍｏｌ％）、化合物（１０−１）５１．７８ｇ（５０ｍｏｌ％）、化合物（１１−１）３３．９５ｇ（４０ｍｏｌ％）を２−ブタノン２００ｇに溶解し、さらにジメチル２，２'−アゾビス（２−メチルプロピオネート）６．４３ｇを投入した単量体溶液を準備し、１００ｇの２−ブタノンを投入した１０００ｍｌの三口フラスコを３０分窒素パージする。窒素パージの後、反応釜を攪拌しながら８０℃に加熱し、事前に準備した上記単量体溶液を滴下漏斗を用いて３時間かけて滴下した。滴下開始を重合開始時間とし、重合反応を６時間実施した。重合終了後、重合溶液は水冷することにより３０℃以下に冷却し、２０００ｇのヘプタンへ投入し、析出した白色粉末をろ別する。ろ別された白色粉末を２度４００ｇのヘプタンにてスラリー上で洗浄した後、ろ別し、５０℃にて１７時間乾燥し、白色粉末の重合体を得た（７４ｇ、収率７４％）。この重合体はＭｗが５，７００であり、化合物（５−１）、化合物（１０−１）、化合物（１１−１）で表される繰り返し単位、各繰り返し単位の含有率が８．４：５２．６：３９．０（ｍｏｌ％）の共重合体であった。この重合体を(メタ)アクリル系重合体（Ａ−１２）とする。 Example 11

14.28 g (10 mol%) of compound (5-1), 51.78 g (50 mol%) of compound (10-1), and 33.95 g (40 mol%) of compound (11-1) were dissolved in 200 g of 2-butanone, Further, a monomer solution charged with 6.43 g of dimethyl 2,2′-azobis (2-methylpropionate) is prepared, and a 1000 ml three-necked flask charged with 100 g of 2-butanone is purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction vessel was heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours, with the start of the dropwise addition as the polymerization start time. After completion of the polymerization, the polymerization solution is cooled to 30 ° C. or lower by water cooling, poured into 2,000 g of heptane, and the precipitated white powder is separated by filtration. The filtered white powder was washed twice with 400 g of heptane on the slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (74 g, yield 74%). . This polymer has Mw of 5,700, and has a repeating unit represented by compound (5-1), compound (10-1), and compound (11-1), and a content of each repeating unit of 8.4: 52.6: 39.0 (mol%). This polymer is referred to as a (meth) acrylic polymer (A-12).

The solubility of each (meth) acrylic polymer obtained in Examples 1 to 11 and Comparative Example 1 in a propylene glycol monomethyl ether acetate solvent was evaluated. In the evaluation method, 5, 10, and 15% by weight of propylene glycol monomethyl ether acetate solutions of each polymer were prepared, and the solubility was visually confirmed. The case where it was transparent visually was evaluated as “good”, and the case where a precipitate was observed was evaluated as “bad”. Table 1 shows the results.

Examples 12 to 22, Comparative Example 2
Each radiation-sensitive resin composition was prepared by blending each of the polymers obtained in Examples 1 to 11 and Comparative Example 1, an acid generator shown below, and other components at a ratio shown in Table 2. A solution was obtained. Various evaluations were performed on the obtained radiation-sensitive resin composition solution. Table 3 shows the film forming conditions, and Table 4 shows the evaluation results. Here, parts are by weight unless otherwise specified.
Acid generator (B)
(B-1): Triphenylsulfonium nonafluoro-n-butanesulfonate acid diffusion controller (C)
(C-1): Triethanolamine solvent (D)
(D-1): Propylene glycol monomethyl ether acetate (D-2): Cyclohexanone evaluation method (1) Sensitivity:
When exposure is performed using an ArF light source, a silicon wafer (ARC29) having an ARC29 (manufactured by Brewer Science) film having a thickness of 780 Å on the wafer surface is used, and each composition solution is spin-coated on a substrate. A resist pattern having a thickness of 0.34 μm, which was formed by applying PB on a hot plate under the conditions shown in Table 3 on a hot plate, was subjected to a mask pattern using a Nikon ArF excimer laser exposure apparatus (numerical aperture: 0.55). Exposure via Thereafter, PEB was performed under the conditions shown in Table 3, and then developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide at 25 ° C. for 60 seconds, washed with water, and dried to form a positive resist pattern. did. At this time, an exposure amount for forming a line-and-space pattern (1L1S) having a line width of 0.16 μm with a line width of 1: 1 was set as an optimum exposure amount, and this optimum exposure amount was set as a sensitivity.
(2) Resolution:
The size of the smallest line-and-space pattern resolved at the optimum exposure was defined as the resolution.
(3) Radiation transmittance:
A resist solution having a thickness of 0.34 μm formed by spin coating the composition solution on quartz glass and performing PB on a hot plate maintained at the temperature conditions shown in Table 3 for the conditions shown in Table 3. , The radiation transmittance was calculated from the absorbance at a wavelength of 193 nm and used as a measure of the transparency in the far ultraviolet region.
(4) Line edge roughness (LER):
When observing the 160nm 1L / 1S pattern resolved at the optimal exposure dose, when observing from above the pattern with Hitachi measuring SEM: S92220, observe the line width at any point and express the measurement variation in 3 sigma In this case, the case where the value was 10 nm or more was regarded as bad, and the case where the value was less than 10 nm was regarded as good.

  The radiation-sensitive resin composition of the present invention has extremely high solubility in a resist solvent, can reduce pattern line edge roughness after development, and is expected to be further miniaturized in the future. It can be used very suitably for production.

Claims (3)

A (meth) acrylic polymer comprising at least one repeating unit selected from the repeating units represented by the following formulas (1) and (2).

(In the formulas (1) and (2), R represents a hydrogen atom or a methyl group, and R ¹ represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms which may have a substituent, or an alkoxy group. R ² represents a linear or branched alkyl group having 3 to 7 carbon atoms or an alicyclic alkyl group, and X represents a methylene group or an ethylene group.) The (meth) acrylic polymer according to claim 1, comprising a repeating unit represented by the following formula (3) together with the formula (1) or the formula (2).

(In the formula (3), R represents a hydrogen atom or a methyl group, and R ³ independently of each other, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear linear group having 1 to 4 carbon atoms. Or, it represents a branched alkyl group, and at least one of R ³ is the alicyclic hydrocarbon group or a derivative thereof, or any two R ³ are bonded to each other, and each is bonded. Forming a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof together with the carbon atom, and the remaining R ³ is a linear or branched alkyl group having 1 to 4 carbon atoms or a C 4 to C 4 alkyl group; 20 represents a monovalent alicyclic hydrocarbon group or a derivative thereof.)   An acid-dissociable group-containing resin which is alkali-insoluble or hardly soluble in alkali and becomes easily alkali-soluble by the action of an acid, and a radiation-sensitive resin composition containing a radiation-sensitive acid generator, 3. A radiation-sensitive resin composition, wherein the group-containing resin contains the (meth) acrylic polymer according to claim 1 or 2.