JP2005314571A - Radial ray sensitive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radial ray sensitive resin having high resolution and line-end foreshortening resistance and provide a copolymer that can be used in this radial ray sensitive resin composition. <P>SOLUTION: This resin composition includes repeating units individually represented by formula (1), formula (2) and formula (3) and has a weight-average molecular weight of 3,000 to 100,000 calculated as polystyrene. In formulas (1), (2) and (3), R<SP>1</SP>and R<SP>3</SP>are each H or methyl; R<SP>2</SP>is a monovalent organic group; R<SP>4</SP>is an acid-dissociating group including a tricyclodecanyl or a tetracyclododecenyl group which may be substituted, R<SP>5</SP>and R<SP>6</SP>are each H, a hydroxy group, a hydroxyalkyl group which may be substituted or a halogen atom; q is an integer of 1 to 3, p is an integer of 0 to 2 and t is an integer of 0 to 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a copolymer and a radiation-sensitive resin composition comprising the copolymer as an acid-dissociable group-containing resin, and particularly (extreme) far ultraviolet rays such as KrF excimer laser, ArF excimer laser, F ₂ excimer laser, EUV and the like. The present invention relates to a radiation-sensitive resin composition used as a chemically amplified resist suitable for microfabrication by various types of radiation such as X-rays such as synchrotron radiation and charged particle beams such as electron beams.

In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, a photolithography technique capable of microfabrication at a level of about 200 nm or less is required.
The use of short-wavelength radiation capable of microfabrication at a level of about 200 nm or less has been studied. Examples of such short-wavelength radiation include a far-ray ultraviolet ray such as an emission line spectrum of a mercury lamp, an excimer laser, and an X-ray. And electron beam. Of these, KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), EUV (wavelength 13 nm, etc., extreme ultraviolet rays), electron beams, and the like are attracting attention.
As a radiation-sensitive resin composition suitable for short-wave radiation, the chemistry between a component having an acid-dissociable functional group and a radiation-sensitive acid generator that generates an acid upon irradiation (hereinafter referred to as “exposure”) Many radiation-sensitive compositions utilizing the amplification effect have been proposed.
As the chemically amplified radiation-sensitive composition, for example, a composition containing a resin having a t-butyl ester group of carboxylic acid or a t-butyl carbonate group of phenol and a radiation-sensitive acid generator has been proposed. (Patent Document 1). In this composition, a t-butyl ester group or t-butyl carbonate group existing in the resin is dissociated by the action of an acid generated by exposure, and the resin has an acidic group composed of a carboxyl group or a phenolic hydroxyl group. As a result, it utilizes the phenomenon that the exposed area of the resist film becomes readily soluble in an alkali developer.

By the way, as the miniaturization of the photolithography process proceeds rapidly, the characteristic requirements required for the photoresist are becoming increasingly severe. Therefore, as a resist having not only high transparency to excimer light but also excellent dry etching resistance, a copolymer containing a specific alicyclic hydrocarbon group in the side chain (Patent Document 2), at least Copolymer excellent in resolution containing a repeating unit containing a tertiary ester alicyclic group having a molecular volume of about 125 cubic angstroms and a repeating unit of a phenol group (Patent Document 3), a specific aliphatic cyclic hydrocarbon group There is known a copolymer (Patent Document 4) in which a plurality of repeating units each having a side chain are combined. As resists having high sensitivity and high resolution, there are known copolymers containing in-molecule repeating units in which an indene derivative constitutes the main chain (Patent Documents 5 and 6).
However, as the photolithographic process is further miniaturized, so-called optical proximity is used to correct the mask pattern shape and prevent deformation of the resist pattern due to the influence of other exposure areas when exposing a fine area resist. It has become difficult to perform effect correction. That is, it is difficult to correct the systematic distortion generated in the manufacturing process by performing geometric correction of the pattern layout due to the miniaturization of the pattern.
For example, there is a change in pattern shape called line end foreshortening, but this phenomenon has a problem that it is difficult to cope with optical proximity correction.
An example of a line pattern is shown in FIG. FIG. 1A is a plan view of the pattern, and FIG. 1B is a cross-sectional view taken along the line BB. A phenomenon in which the thickness t of the resist pattern 2 formed on the substrate 1 becomes thinner in the direction of the tip 2a of the pattern is line end foreshortening. This phenomenon can be determined by measuring the threshold value of the length a shown in FIG. When this defect occurs, the etching becomes defective and the processing accuracy becomes unstable, and there is a possibility of a broken line. Conventionally, it can be dealt with by geometric correction of the pattern layout such as the shape of the hammerhead, but it has become difficult to deal with by miniaturization of the pattern.
JP-B-2-27660 JP-A-10-161313 JP 2001-194792 A JP 2002-303978 A JP 2002-202610 A JP 2003-84440 A

The present invention has been made to cope with such problems. For example, as a chemically amplified resist sensitive to far ultraviolet rays typified by KrF excimer laser, ArF excimer laser or F ₂ excimer laser, resolution and line end are proposed. It aims at providing the radiation sensitive resin composition excellent in foreshortening tolerance, and the copolymer which can be used for this radiation sensitive resin composition.

The copolymer of the present invention contains repeating units represented by the following formula (1), formula (2) and formula (3), respectively, and has a polystyrene-reduced weight average molecular weight measured by gel permeation chromatography of 3,000. ~ 100,000.
In Formula (1), Formula (2), and Formula (3), R ¹ and R ³ represent a hydrogen atom or a methyl group, R ² represents a monovalent organic group, and R ⁴ has a substituent. Represents an acid-dissociable group containing a tricyclodecanyl group or the same tetracyclododecenyl group, wherein R ⁵ and R ⁶ are a hydrogen atom, a hydroxy group, a substituted hydroxyalkyl group, linear or branched Represents an alkyl group, a substituted alkoxyl group, or a halogen atom, q is an integer of 1 to 3, p is an integer of 0 to 2, and t is an integer of 0 to 4.

The radiation-sensitive resin composition of the present invention comprises an acid-dissociable group-containing resin (A) that is insoluble or hardly soluble in alkali and easily soluble in alkali by the action of an acid, and a radiation-sensitive acid generator (B). In terms of polystyrene measured by gel permeation chromatography, wherein the acid-dissociable group-containing resin (A) contains repeating units represented by the following formulas (1), (2) and (3), respectively. The weight average molecular weight is 3,000 to 100,000.
The radiation sensitive acid generator (B) is at least one compound selected from a diazomethane compound and a sulfonium salt.

  Since the copolymer of the present invention contains repeating units represented by formula (1), formula (2), and formula (3), respectively, in a resist using this copolymer as a resin, the tip portion of the line pattern The resist dissolution rate caused by the difference in exposure intensity can be adjusted. Therefore, the resolution is excellent and the line end foreshortening phenomenon can be suppressed.

In the formula (1), examples of the monovalent organic group represented by R ² include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, and a 1-methylpropyl group. A straight-chain or branched alkyl group having 1 to 12 carbon atoms such as a group, t-butyl group; methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group A linear or branched alkoxyl group having 1 to 12 carbon atoms such as a group, 1-methylpropoxy group, t-butoxy group and the like. Of these, methyl, ethyl, n-butyl and t-butyl are preferred.
Moreover, q in Formula (1) is an integer of 1 to 3, preferably 1, and p is an integer of 0 to 2, preferably 0.

In the formula (2), R ⁴ represents an acid-dissociable group containing a tricyclodecanyl group or tetracyclododecenyl group which may have a substituent.
In order to become an acid dissociable group, a carbon atom forming a ring of a tricyclodecanyl group or a tetracyclododecenyl group bonded to an oxygen atom is a quaternary carbon atom having a substituent on the carbon atom. It is. As a substituent for forming a quaternary carbon atom, a linear or branched monovalent alkyl group having 1 to 8 carbon atoms is preferable.
Examples of the monovalent alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n- A heptyl group, n-hexyl group, n-octyl group, etc. are mentioned.
In the present invention, examples of the monovalent alkyl group suitable for improving the resolution and improving the line end foreshortening resistance include a methyl group, an ethyl group, and an i-propyl group.
The tricyclodecanyl group or tetracyclododecenyl group may have a substituent, and examples of the substituent include a methyl group and an ethyl group.

In the formula (3), R ⁵ and R ⁶ each independently represent a hydrogen atom, a hydroxy group, a substituted hydroxyalkyl group, a linear or branched alkyl group, a substituted alkoxyl group, or a halogen atom.
Examples of the replaceable hydroxyalkyl group include a hydroxymethyl group, a trifluoromethylated hydroxymethyl group, a ditrifluoromethylated hydroxymethyl group, and a hydroxyethyl group.
Examples of the linear or branched alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group, and a t-butyl group. Examples thereof include a linear or branched alkyl group having 1 to 12 carbon atoms such as a group, and an n-octyl group.
Examples of the substituted alkoxyl group include a methoxy group, an ethoxy group, an isopropoxy group, an n-propoxy group, an n-butoxy group, and a t-butoxy group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Moreover, t in Formula (3) is an integer of 0 to 4, preferably 0.

In the copolymer of the present invention, the repeating unit represented by the formula (1) is a single amount of a compound obtained by using a corresponding hydroxystyrene derivative as a monomer or hydrolyzing to obtain a hydroxystyrene derivative. By using as a body, the repeating unit represented by the formula (2) uses the corresponding acrylic acid derivative as a monomer, and the repeating unit represented by the formula (3) It can be obtained by using as a polymer.
Examples of preferable monomers that generate the repeating unit represented by the formula (1) include p-acetoxystyrene and p- (1-ethoxyethoxy) styrene. These monomers After forming a copolymer, a repeating unit represented by the formula (1) is generated by a side chain hydrolysis reaction.
The following formula (2-1) to formula (2-4) may be mentioned as preferable monomers among the monomers that generate the repeating unit represented by formula (2).
Examples of preferable monomers among the monomers that generate the repeating unit represented by the formula (3) include indene, hydroxyindene, and 1-methylindene.

In the copolymer of the present invention, the copolymer obtained using only the monomer that generates the formula (1), the formula (2), and the formula (3) improves the sensitivity and suppresses the line end foreshortening phenomenon. This is a preferred copolymer.
In the copolymer, the proportion of the repeating units represented by formula (1), formula (2) and formula (3) is such that the number of repeating units represented by formula (1) is 20 with respect to the total of all repeating units. To 90 mol%, preferably 30 to 90 mol%, more preferably 50 to 90 mol%, and the repeating unit represented by the formula (2) is 1 to 50 mol%, preferably 1 to 40 mol%, Preferably it is 5-30 mol%, and the repeating unit represented by Formula (3) is 1-40 mol%, Preferably it is 1-30 mol%, More preferably, it is 1-20 mol%.
When the repeating unit represented by the formula (1) is less than 20 mol%, the substrate adhesion may be insufficient, and when it exceeds 90 mol%, the contrast of the resist film after development may be inferior. If the repeating unit represented by the formula (2) is less than 1 mol%, the line end foreshortening performance may not be sufficiently obtained, and if it exceeds 50 mol%, the dry etching resistance may be insufficient. . If the repeating unit represented by formula (3) is less than 1 mol%, the dry etching resistance may be insufficient, and if it exceeds 40 mol%, the resolution may deteriorate.

The copolymer of the present invention can further contain a repeating unit derived from a non-acid dissociable compound. Examples of the non-acid dissociable compound include styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, isobornyl acrylate, tricyclodecanyl (meth) acrylate, and tetracyclodode. Examples include senyl (meth) acrylate. Of these, styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, and tricyclodecanyl acrylate are preferable.
The repeating unit derived from these non-acid dissociable compounds is usually 20 mol% or less in consideration of the balance between resolution performance and dry etching resistance.

  The method for synthesizing the copolymer is not particularly limited, and can be obtained, for example, by known radical polymerization or anionic polymerization. Further, the side chain hydroxystyrene unit is obtained by hydrolyzing an acetoxy group or the like in the presence of a base or an acid in an organic solvent to obtain a copolymer having each repeating unit. .

  The radical polymerization can be performed as follows, for example. The reaction is carried out by heating the monomer and, if necessary, another monomer, for example, to 50 ° C. to 200 ° C. with stirring in a suitable organic solvent in a nitrogen atmosphere in the presence of a radical polymerization initiator. As the radical polymerization initiator, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobis- (4-methoxy-2) , 4-Dimethylvaleronitrile) 2,2′-azobismethylbutyronitrile, 2,2′-azobiscyclohexanecarbonitrile, cyanomethylethylazoformamide, 2,2′-azobis (2,4-dimethylpropionic acid) Methyl), azo compounds such as 2,2′-azobiscyanovaleric acid; benzoyl peroxide, lauroyl peroxide, 1,1′-bis- (t-butylperoxy) cyclohexane, 3,5,5-trimethylhexanoyl Examples include peroxides, organic peroxides such as t-butylperoxy-2-ethylhexanoate, and hydrogen peroxide. Further, 2,2,6,6-tetramethyl-1-piperidinyloxy, iodine, mercaptan, styrene dimer or the like can be added as a polymerization aid.

Moreover, anionic polymerization can be implemented as follows, for example. It is carried out by maintaining the monomer under stirring in a suitable organic solvent in the presence of an anionic polymerization initiator at a temperature of, for example, -100 ° C to 50 ° C. Examples of the anionic polymerization initiator include organic compounds such as n-butyllithium, s-butyllithium, t-butyllithium, ethyllithium, ethylsodium, 1,1-diphenylhexyllithium, 1,1-diphenyl-3-methylpentyllithium, etc. Alkali metals are used.
Furthermore, in the synthesis of the above polymer, it is possible to carry out a polymerization reaction by heating without using a polymerization initiator and to carry out cationic polymerization.

Hydroxystyrene units can be introduced by hydrolyzing the side chain of the obtained polymer. Examples of the acid used in the hydrolysis reaction include p-toluenesulfonic acid and its hydrate, methanesulfonic acid, trifluoromethanesulfonic acid, malonic acid, succinic acid, and 1,1,1-fluoroacetic acid. Acids; inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, hydrobromic acid; or salts such as pyridinium p-toluenesulfonate, ammonium p-toluenesulfonate, 4-methylpyridinium p-toluenesulfonate.
Furthermore, examples of the base include inorganic bases such as potassium hydroxide, sodium hydroxide, sodium carbonate and potassium carbonate; organic bases such as triethylamine, N-methyl-2-pyrrolidone, piperidine and tetramethylammonium hydroxide.

  Suitable organic solvents used for the polymerization and hydrolysis include ketones such as acetone, methyl ethyl ketone, and methyl amyl ketone; ethers such as diethyl ether and tetrahydrofuran (THF); alcohols such as methanol, ethanol, propanol, and the like; Aliphatic hydrocarbons such as hexane, heptane and octane; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated alkyls such as chloroform, bromoform, methylene chloride, methylene bromide and carbon tetrachloride; ethyl acetate, Esters such as butyl acetate, ethyl lactate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cellosolves; non-prototypes such as dimethylformamide, dimethyl sulfoxide, hexamethylphosphoramide Sex polar solvent such like. Among these, particularly preferred are acetone, methyl amyl ketone, methyl ethyl ketone, tetrahydrofuran, methanol, ethanol, propanol, ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and the like. .

The reaction temperature in the polymerization varies depending on the type of initiator. When alkyl lithium is used in the anionic polymerization, it is preferably -100 ° C to 50 ° C, more preferably -78 ° C to 30 ° C. In the case of using an azo initiator or peroxide initiator in radical polymerization, a temperature at which the initiator half-life is about 10 minutes to about 30 hours is preferable, and more preferably, the initiator half-life is about 30 minutes to about 10 hours. Temperature.
The reaction time varies depending on the type of initiator and the reaction temperature, but the reaction time during which 50% or more of the initiator is consumed is desirable, and in many cases, about 0.5 to 24 hours.

The polystyrene-reduced weight average molecular weight (hereinafter also referred to as “Mw”) of the copolymer measured by gel permeation chromatography (GPC) is preferably 3,000 to 100,000, more preferably 5,000 to 60. The ratio (Mw / Mn) between Mw and polystyrene-equivalent number average molecular weight (hereinafter also referred to as “Mn”) measured by GPC is usually 1 ~ 5.
The copolymer can be used as an acid-dissociable group-containing resin which is insoluble in alkali or hardly soluble in alkali and easily soluble in alkali by the action of an acid.

Radiation-sensitive acid generators (hereinafter referred to as “acid generators”) that generate acids upon exposure include (1) sulfonimide compounds, (2) disulfonylmethane compounds, (3) onium salt compounds, (4) Examples include sulfone compounds, (5) sulfonic acid ester compounds, and (6) diazomethane compounds.
Examples of these acid generators are shown below.
(1) Sulfonimide compound As a sulfonimide compound, it represents with following formula (4), for example.
In the above formula (4), R ⁸ represents a monovalent organic group, and R ⁷ represents a divalent organic group.
Examples of the monovalent organic group include a divalent organic group such as a substituted or unsubstituted linear or branched alkyl group, a substituted or unsubstituted cyclic alkyl group, a substituted or unsubstituted aryl group, and a perfluoroalkyl group. Examples thereof include a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkenylene group, a substituted or unsubstituted phenylene group, and the like.

  Specific examples of the sulfonimide compound include N- (trifluoromethylsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide. N- (10-camphorsulfonyloxy) succinimide, N- (10-camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (10-camphorsulfonyl) Oxy) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (p-toluenesulfonyloxy) succinimide, N- (p-toluenesulfonyloxy) bicyclo [ 2.2.1] Hept-5-ene-2,3-dicarboximide, N- (4-trifluoromethylbenzene) Sulfonyloxy) succinimide, N- (4-trifluoromethylbenzenesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (perfluorobenzenesulfonyloxy) succinimide, N -(Perfluorobenzenesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluorobutylsulfonyloxy) succinimide, N- (nonafluorobutylsulfonyloxy) Bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (perfluorooctanesulfonyloxy) succinimide, N- (perfluorooctanesulfonyloxy) bicyclo [2.2.1] Hept-5-ene-2,3-dicarboximide, N- (benzene Sulfonyloxy) succinimide, N- (benzenesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (benzenesulfonyloxy) -7-oxabicyclo [2.2. 1] hept-5-ene-2,3-dicarboximide, N-{(5-methyl-5-carboxymethanebicyclo [2.2.1] hept-2-yl) sulfonyloxy} succinimide and the like. .

  Among the sulfonamides, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (10-camphorsulfonyloxy) succinimide, N -(P-toluenesulfonyloxy) succinimide, N- (nonafluorobutylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (benzenesulfonyloxy) bicyclo [ 2.2.1] Hept-5-ene-2,3-dicarboximide, N-{(5-methyl-5-carboxymethanebicyclo [2.2.1] hept-2-yl) sulfonyloxy} succinimide Is preferred.

(2) As a disulfonylmethane compound, it represents with following formula (5), for example.
In the formula, R ⁹ and R ¹⁰ are each independently a linear or branched monovalent aliphatic hydrocarbon group, cycloalkyl group, aryl group, aralkyl group or other monovalent organic group having a hetero atom. X and Y each independently represent an aryl group, a hydrogen atom, a linear or branched monovalent aliphatic hydrocarbon group or another monovalent organic group having a hetero atom, and X and At least one of Y is an aryl group, or X and Y are connected to each other to form a monocyclic or polycyclic ring having at least one unsaturated bond, or X and Y are connected to each other; Thus, a group represented by the following formula (5-1) is formed.
X ′ and Y ′ each independently represent a hydrogen atom, a halogen atom, a linear or branched alkyl group, a cycloalkyl group, an aryl group or an aralkyl group, or bonded to the same or different carbon atoms. X ′ and Y ′ are connected to each other to form a carbon monocyclic structure, and a plurality of X ′ and Y ′ may be the same or different from each other, and r is an integer of 2 to 10. .

(3) Onium salt compound Examples of the onium salt compound include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, ammonium salts, and pyridinium salts.
Specific examples of the onium salt compound include bis (4-t-butylphenyl) iodonium nonafluorobutanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, and bis (4-t-butylphenyl) iodonium perfluoro. Octanesulfonate, bis (4-t-butylphenyl) iodonium p-toluenesulfonate, bis (4-t-butylphenyl) iodonium 10-camphorsulfonate, 4-trifluoromethylbenzenesulfonate, bis (4-t-butylphenyl) Iodonium perfluorobenzenesulfonate, diphenyliodonium nonafluorobutanesulfonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium perfluoroocta Sulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodoniumbenzenesulfonate, diphenyliodonium10-camphorsulfonate, diphenyliodonium4-trifluoromethylbenzenesulfonate, diphenyliodonium perfluorobenzenesulfonate, triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfoniumtrifluoro Lomethanesulfonate, triphenylsulfonium perfluorooctanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfoniumbenzenesulfonate, triphenylsulfonium 10-camphorsulfonate, triphenylsulfonium 4-trifluoromethylbenzenesulfonate , Triphenylsulfonium perfluorobenzenesulfonate, 4-hydroxyphenyl diphenylsulfonium trifluoromethanesulfonate, tri (p-methoxyphenyl) sulfonium nonafluorobutanesulfonate, tri (p-methoxyphenyl) sulfonium trifluoromethanesulfonate, tri (p-methoxy) Phenyl) sulfonium perfluorooctanesulfonate, tri (p-methoxyphenyl) sulfonium p-toluenesulfonate, tri (p-methoxyphenyl) sulfoniumbenzenesulfonate, tri (p-methoxyphenyl) sulfonium 10-camphorsulfonate, bis (p-fluoro) Phenyl) iodonium trifluoromethanesulfonate, bis (p-fluorophenyl) iodonium Nonafluoromethanesulfonate, bis (p-fluorophenyl) iodonium camphorsulfonate, (p-fluorophenyl) (phenyl) iodonium trifluoromethanesulfonate, tris (p-fluorophenyl) sulfonium trifluoromethanesulfonate, tris (p-fluorophenyl) sulfonium Examples include p-toluenesulfonate, (p-fluorophenyl) diphenylsulfonium trifluoromethanesulfonate, and the like.

(4) Sulfone Compound Examples of the sulfone compound include β-ketosulfone, β-sulfonylsulfone, and α-diazo compounds thereof.
Specific examples of the sulfone compound include phenacylphenylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane, 4-trisphenacylsulfone, and the like.

(5) Sulfonic acid ester compound Examples of the sulfonic acid ester compound include alkyl sulfonic acid esters, haloalkyl sulfonic acid esters, aryl sulfonic acid esters, and imino sulfonates.
Specific examples of the sulfonate compound include benzoin tosylate, pyrogallol tris (trifluoromethanesulfonate), pyrogallol tris (nonafluoro-n-butanesulfonate), pyrogallol tris (methanesulfonate), nitrobenzyl-9,10-diethoxyanthracene. -2-sulfonate, α-methylol benzoin tosylate, α-methylol benzoin n-octane sulfonate, α-methylol benzoin trifluoromethane sulfonate, α-methylol benzoin n-dodecane sulfonate, and the like.

(6) Diazomethane compound As a diazomethane compound, the compound represented by following formula (6) is mentioned, for example.
In the formula, R ¹¹ and R ¹² each independently represent a monovalent group such as an alkyl group, an aryl group, a halogen-substituted alkyl group, or a halogen-substituted aryl group.

  Specific examples of diazomethane compounds include bis (trifluoromethanesulfonyl) diazomethane, bis (cyclohexanesulfonyl) diazomethane, bis (benzenesulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, methanesulfonyl-p-toluenesulfonyldiazomethane, cyclohexanesulfonyl -1,1-dimethylethylsulfonyldiazomethane, bis (1,1-dimethylethanesulfonyl) diazomethane, bis (3,3-dimethyl-1,5-dioxaspiro [5.5] dodecane-8-sulfonyl) diazomethane, bis ( 1,4-dioxaspiro [4.5] undecan-7-sulfonyl) diazomethane, bis (t-butylsulfonyl) diazomethane, and the like.

Among the acid generators, preferred acid generators are exemplified below.
Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium p-toluenesulfonate, bis (4 -T-butylphenyl) iodonium 10-camphorsulfonate, bis (4-t-butylphenyl) iodonium 2-trifluoromethylbenzenesulfonate, bis (4-t-butylphenyl) iodonium 4-trifluoromethylbenzenesulfonate, bis ( 4-t-butylphenyl) iodonium 2,4-difluorobenzenesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium perfluoro-n-butanesulfonate, Riphenylsulfonium p-toluenesulfonate, triphenylsulfonium 10-camphorsulfonate, triphenylsulfonium 2-trifluoromethylbenzenesulfonate, triphenylsulfonium 4-trifluorobenzenesulfonate, triphenylsulfonium 2,4-difluoromethylbenzenesulfonate, N -(Trifluoromethanesulfonyloxy) succinimide, N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (10-camphorsulfonyloxy) succinimide, N- (10-camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide and N-{(5-methyl-5-carboxy) Boxymethanebicyclo [2.2.1] hept-2-yl) sulfonyloxy} succinimide, bis (4-tert-butylphenyl) iodonium perfluorooctane sulfonate, diphenyliodonium nonafluorobutanesulfonate, diphenyliodonium trifluoromethanesulfonate, Diphenyliodonium perfluorooctanesulfonate, diphenyliodonium 10-camphorsulfonate, triphenylsulfonium perfluorooctanesulfonate, tri (p-methoxyphenyl) sulfonium trifluoromethanesulfonate, tri (p-methoxyphenyl) sulfonium 10-camphorsulfonate, bis (p -Fluorophenyl) iodonium trifluoromethanesulfonate, bis (p-fluoro Rophenyl) iodonium nonafluoromethanesulfonate, bis (p-fluorophenyl) iodonium camphorsulfonate, (p-fluorophenyl) (phenyl) iodonium trifluoromethanesulfonate, tris (p-fluorophenyl) sulfonium trifluoromethanesulfonate, tris (p-fluoro) Phenyl) sulfonium p-toluenesulfonate, (p-fluorophenyl) diphenylsulfonium trifluoromethanesulfonate, N-{(5-methyl-5-carboxymethanebicyclo [2.2.1] hept-2-yl) sulfonyloxy} succinimide N- (nonafluorobutylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (p-toluenesulfonyl) Oxy) succinimide, N- (benzenesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, bis (cyclohexanesulfonyl) diazomethane, bis (3,3-dimethyl-1, At least selected from the group of 5-dioxaspiro [5.5] dodecan-8-sulfonyl) diazomethane, bis (1,4-dioxaspiro [4.5] undecan-7-sulfonyl) diazomethane, bis (t-butylsulfonyl) diazomethane One type is preferably used.

In the present invention, for the copolymer containing repeating units represented by formula (1), formula (2) and formula (3), among the acid generators, a diazomethane compound, a sulfonium salt, or Use of these mixtures is particularly preferable because sensitivity and line end foreshortening resistance can be improved.
In this invention, the usage-amount of an acid generator becomes like this. Preferably it is 0.1-20 weight part with respect to 100 weight part of resin components, More preferably, it is 0.5-15 weight part. In the present invention, two or more acid generators can be mixed and used.

The radiation-sensitive resin composition of the present invention can contain an alkali-soluble resin, an acid diffusion controller, and other additives.
Examples of the alkali-soluble resin include poly (p-hydroxystyrene), partially hydrogenated poly (p-hydroxystyrene), poly (m-hydroxystyrene), poly (m-hydroxystyrene), and (p-hydroxystyrene) ( m-hydroxystyrene) copolymer, (p-hydroxystyrene) (styrene) copolymer, novolac resin, polyvinyl alcohol, polyacrylic acid, and the like. The Mw of these resins is preferably 1,000 to 1,000,000, more preferably 2,000 to 100,000. These alkali-soluble resins can be used alone or in admixture of two or more.
The blending amount of the alkali-soluble resin is preferably 30 parts by weight or less per 100 parts by weight of the polymer component (A).

The acid diffusion control agent controls the diffusion phenomenon in the resist film of the acid generated from the acid generator by exposure, and has an action of suppressing an undesirable chemical reaction in the non-exposed region. By using such an acid diffusion control agent, the storage stability of the composition is improved, the resolution of the resist is improved, and the change of the line width of the resist pattern due to the fluctuation of PED can be suppressed, thereby stabilizing the process. It is extremely excellent in properties.
As the acid diffusion controller, a nitrogen-containing organic compound whose basicity is not changed by exposure or heat treatment in the resist pattern forming step is preferable.
As such a nitrogen-containing organic compound, for example, a compound represented by the following formula (7) (hereinafter referred to as “nitrogen-containing compound (I)”), a diamino compound having two nitrogen atoms in the same molecule ( Hereinafter referred to as “nitrogen-containing compound (II)”, diamino polymer having 3 or more nitrogen atoms (hereinafter referred to as “nitrogen-containing compound (III)”), amide group-containing compound, urea compound, nitrogen-containing heterocyclic compound Etc.
In the formula, R ¹³ may be the same as or different from each other, and represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group (the hydrogen atom such as an alkyl group, an aryl group or an aralkyl group is, for example, a hydroxy group, Including the case where it is substituted with a functional group).

  Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; di-n-butylamine, di-n- Dialkylamines such as pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine; triethylamine, tri-n-propylamine, Trialkylamines such as tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine Aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methyl Aromatic amines such as ruaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, 1-naphthylamine, alkanolamines such as N-ethyldiethanolamine, triisopropanolamine, ethanolamine, diethanolamine, triethanolamine, etc. Is mentioned.

Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, tetramethylenediamine, Hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 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- The [1- (4-aminophenyl) -1-methylethyl] benzene, and the like.
Examples of the nitrogen-containing compound (III) include polymers of polyethyleneimine, polyallylamine, dimethylaminoethylacrylamide, and the like.

Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like. Can be mentioned.
Examples of urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tributylthiourea and the like. .
Examples of the nitrogen-containing heterocyclic compound include imidazoles such as imidazole, benzimidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, 2-phenylbenzimidazole; pyridine, 2-methylpyridine, 4-methylpyridine. Pyridine such as 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, N-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 8-oxyquinoline, acridine In addition to the above, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, morpholine, 4-methylmorpholine, piperazine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, etc. It is done.

  A base precursor having an acid dissociable group can also be used as the acid diffusion controller. Specifically, N- (t-butoxycarbonyl) piperidine, N- (t-butoxycarbonyl) imidazole, N- (t-butoxycarbonyl) benzimidazole, N- (t-butoxycarbonyl) 2-phenylbenzimidazole, N -(T-Butoxycarbonyl) dioctylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxycarbonyl) diphenylamine and the like can be mentioned.

Of these nitrogen-containing organic compounds, nitrogen-containing compounds (I) and nitrogen-containing heterocyclic compounds are preferred. Further, among the nitrogen-containing compounds (I), trialkylamines and alkanolamines are particularly preferable, and among the nitrogen-containing heterocyclic compounds, imidazoles are particularly preferable.
The acid diffusion control agents can be used alone or in admixture of two or more.
The compounding amount of the acid diffusion controller is 15 parts by weight or less, preferably 0.001 to 10 parts by weight, and more preferably 0.005 to 5 parts by weight with respect to 100 parts by weight of the resin. In this case, when the compounding amount of the acid diffusion controller exceeds 15 parts by weight, the sensitivity as a resist and the developability of the exposed part tend to be lowered. If the blending 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 lowered depending on the process conditions.

In the radiation sensitive resin composition of the present invention, a surfactant exhibiting an effect of improving the coating property and striation of the composition, the developing property as a resist, and the like can be blended.
Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, polyethylene glycol dilaurate, and polyethylene glycol distearate. Examples of commercially available products include F-top EF301, EF303, EF352 (manufactured by Tochem Products), Megafax F171, F173 (manufactured by Dainippon Ink & Chemicals, Inc.), Florard FC430, FC431 ( Manufactured by Sumitomo 3M Limited), Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (Asahi Glass Co., Ltd.), KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, No. 95 (Kyoeisha Chemical Co., Ltd.) and the like.
The compounding amount of the surfactant is preferably 2 parts by weight or less with respect to 100 parts by weight of the acid dissociable group-containing resin.
Further, other sensitizers can be blended. Examples of preferred sensitizers include carbazoles, benzophenones, rose bengals, anthracenes and the like.
The blending amount of the sensitizer is preferably 50 parts by weight or less with respect to 100 parts by weight of the acid dissociable group-containing resin.
In addition, by blending dyes and / or pigments, the latent image of the exposed area can be visualized, and the influence of halation during exposure can be mitigated. By blending an adhesion aid, adhesion to the substrate is further improved. can do.
Furthermore, as other additives, an antihalation agent such as 4-hydroxy-4′-methylchalcone, a shape improver, a storage stabilizer, an antifoaming agent, and the like can be blended.

When the radiation-sensitive resin composition of the present invention is used, the total solid content is, for example, 0. It is prepared as a composition solution by uniformly dissolving in a solvent so as to be ˜50 wt%, preferably 1 to 40 wt%, and then filtering through a filter having a pore size of about 200 nm, for example.
Examples of the solvent used for the preparation of the composition solution include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, ethylene glycol mono-n-butyl ether acetate and the like. Glycol monoalkyl ether acetates; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether; propylene glycol dimethyl ether, propylene glycol diethyl Ether, propylene glycol di-n-propyl ether, propylene Propylene glycol dialkyl ethers such as recall di-n-butyl ether; propylene glycol monoalkyl such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-n-butyl ether acetate Ether acetates; lactate esters such as methyl lactate, ethyl lactate, n-propyl lactate, i-propyl lactate; n-amyl formate, i-amyl formate, ethyl acetate, n-propyl acetate, i-propyl acetate, Aliphatic carboxylates such as n-butyl acetate, i-butyl acetate, n-amyl acetate, i-amyl acetate, i-propyl propionate, n-butyl propionate and i-butyl propionate Ethyl hydroxyacetate, ethyl 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, Methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, 3-methyl-3-methoxybutyl Other esters such as butyrate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate, ethyl pyruvate; aromatic hydrocarbons such as toluene, xylene; methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4 Ketones such as heptanone and cyclohexanone; amides such as N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide and N-methylpyrrolidone; lactones such as γ-butyrolacun Can be mentioned.
These solvents can be used alone or in admixture of two or more.

When forming a resist pattern from the radiation-sensitive resin composition of the present invention, the composition solution prepared as described above is applied by appropriate coating means such as spin coating, cast coating, roll coating, etc. A resist film is formed by coating on a substrate such as a silicon wafer or a wafer coated with aluminum, and a heat treatment (hereinafter referred to as “PB”) is performed at a temperature of about 70 ° C. to 160 ° C. in some cases. After that, exposure is performed through a predetermined mask pattern. The radiation used in this case depends on the type of the acid generator, for example, far ultraviolet rays such as F ₂ excimer laser (wavelength 157 nm), ArF excimer laser (wavelength 193 nm), KrF excimer laser (wavelength 248 nm), and synchrotron. X-rays such as radiation, and charged particle beams such as electron beams are appropriately selected and used. Moreover, exposure conditions, such as exposure amount, are suitably selected according to the compounding composition of a radiation sensitive resin composition, the kind of each additive, etc. In the present invention, far ultraviolet rays such as KrF excimer laser (wavelength 248 nm) are preferably used.

In the present invention, in order to stably form a high-precision fine pattern, it is preferable to perform heat treatment (hereinafter referred to as “PEB”) for 30 seconds or more at a temperature of 70 ° C. to 160 ° C. after exposure. In this case, if the post-exposure baking temperature is less than 70 ° C., the sensitivity variation due to the type of substrate may spread.
Thereafter, development is performed with an alkali developer at 10 ° C. to 50 ° C., 10 seconds to 200 seconds, preferably 15 ° C. to 30 ° C., 15 seconds to 100 seconds, particularly preferably 20 ° C. to 25 ° C., 15 seconds to 90 seconds. As a result, a predetermined resist pattern is formed.
As the alkaline developer, for example, an alkaline compound such as tetraalkylammonium hydroxide is usually used at a concentration of 1% by weight to 10% by weight, preferably 1% by weight to 5% by weight, particularly preferably 1 to 3% by weight. An alkaline aqueous solution dissolved so as to be used is used.
In addition, a water-soluble organic solvent such as methanol or ethanol or a surfactant can be appropriately added to the developer composed of the alkaline aqueous solution. In forming the resist pattern, a protective film can be provided on the resist film in order to prevent the influence of basic impurities contained in the environmental atmosphere.

Example 1
After dissolving 104 g of p-acetoxystyrene, 22 g of 8-ethyl-8-tricyclodecyl acrylate, 25 g of indene, 6 g of azobisisobutyronitrile and 1 g of t-dodecyl mercaptan in 160 g of propylene glycol monomethyl ether, The reaction temperature was kept at 70 ° C. and polymerization was carried out for 16 hours. After the polymerization, the reaction solution was dropped into a large amount of n-hexane to coagulate and purify the resulting copolymer.
Next, 150 g of propylene glycol monomethyl ether was added to the copolymer, and then 300 g of methanol, 80 g of triethylamine, and 15 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in acetone, then dripped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.

The obtained copolymer had Mw of 11,000 and Mw / Mn of 2.0. As a result of ¹³ C-NMR analysis, p-hydroxystyrene and 8-ethyl represented by the following formula (A-1) were obtained. The copolymerization molar ratio of -8-tricyclodecyl acrylate and indene was 82: 12: 6. This copolymer is referred to as “resin (A-1)”. Hereinafter, in the indications of resin (A-1) to resin (A-8), the subscript represents the molar ratio of repeating units, and the copolymer has these repeating units bonded to each other in a random or block form. Represents that you are doing.
Measurement of Mw and Mn of the respective Examples and the resin obtained in Reference Synthesis Example uses a Tosoh Co., Ltd. GPC column (G2000H _XL 2 present, one G3000H _XL, one G4000H _XL), flow rate 1. It was measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under the analysis conditions of 0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C.

Example 2
104 g of p-acetoxystyrene, 53 g of 8-methyl-8-tricyclodecyl acrylate, 90 g of indene, 6 g of azobisisobutyronitrile and 1 g of t-dodecyl mercaptan are dissolved in 230 g of propylene glycol monomethyl ether and reacted in a nitrogen atmosphere. Polymerization was carried out for 16 hours while maintaining the temperature at 70 ° C. After the polymerization, the reaction solution was dropped into a large amount of hexane to coagulate and purify the resulting copolymer. Next, 150 g of propylene glycol monomethyl ether was added to the purified copolymer, and then 300 g of methanol, 80 g of triethylamine and 15 g of water were further added, and a hydrolysis reaction was carried out for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in acetone, then dripped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.
The obtained copolymer had Mw of 11,500 and Mw / Mn of 1.9. As a result of ¹³ C-NMR analysis, p-hydroxystyrene and 8-methylstyrene represented by the following formula (A-2) were used. The copolymerization molar ratio of -8-tricyclodecyl acrylate and indene was 60:23:17. This copolymer is referred to as “resin (A-2)”.

Example 3
After dissolving 104 g of p-acetoxystyrene, 52 g of 3-methyl-3-tetracyclododecenyl acrylate, 25 g of indene, 6 g of azobisisobutyronitrile and 0.9 g of t-dodecyl mercaptan in 160 g of propylene glycol monomethyl ether The polymerization was carried out for 16 hours under a nitrogen atmosphere while maintaining the reaction temperature at 70 ° C. After the polymerization, the reaction solution was dropped into a large amount of n-hexane to coagulate and purify the resulting copolymer.
Next, 150 g of propylene glycol monomethyl ether was added to the copolymer, and then 300 g of methanol, 80 g of triethylamine, and 15 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in acetone, then dripped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.
The obtained copolymer had Mw of 15,000 and Mw / Mn of 2.0, and as a result of ¹³ C-NMR analysis, p-hydroxystyrene and 3-methyl represented by the following formula (A-3) The copolymerization molar ratio of -3-tetracyclododecenyl acrylate and indene was 72: 23: 5. This copolymer is referred to as “resin (A-3)”. The indene was mixed in an excessive amount with respect to the production ratio of the copolymer.

Example 4
After dissolving 104 g of p-acetoxystyrene, 26 g of 3-ethyltetracyclododecenyl methacrylate, 25 g of indene, 6 g of azobisisobutyronitrile and 1 g of t-dodecyl mercaptan in 160 g of propylene glycol monomethyl ether, The reaction temperature was kept at 70 ° C. and polymerization was carried out for 16 hours. After the polymerization, the reaction solution was dropped into a large amount of n-hexane to coagulate and purify the resulting copolymer.
Next, 150 g of propylene glycol monomethyl ether was added to the copolymer, and then 300 g of methanol, 80 g of triethylamine, and 15 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in acetone, then dripped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.
The obtained copolymer had Mw of 11,000 and Mw / Mn of 2.0. As a result of ¹³ C-NMR analysis, p-hydroxystyrene and 3-ethyl represented by the following formula (A-4) were obtained. The copolymerization molar ratio of -3-tetracyclododecenyl methacrylate and indene was 82: 12: 6. This copolymer is referred to as “resin (A-4)”.

Reference synthesis example 1
100 g of p-acetoxystyrene, 25 g of t-butyl acrylate, 18 g of styrene, 6 g of azobisisobutyronitrile and 1 g of t-dodecyl mercaptan are dissolved in 230 g of propylene glycol monomethyl ether, and the reaction temperature is set to 70 ° C. in a nitrogen atmosphere. The polymerization was continued for 16 hours. After the polymerization, the reaction solution was dropped into a large amount of n-hexane to coagulate and purify the resulting copolymer. Next, 150 g of propylene glycol monomethyl ether was added to the purified copolymer, and then 300 g of methanol, 80 g of triethylamine and 15 g of water were further added, and a hydrolysis reaction was carried out for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in acetone, then dripped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.
The obtained copolymer had Mw of 11,500 and Mw / Mn of 1.6. As a result of ¹³ C-NMR analysis, p-hydroxystyrene and acrylic acid t represented by the following formula (A-5) were obtained. -The copolymerization molar ratio of butyl and styrene was 61:19:20. This copolymer is referred to as “resin (A-5)”.

Reference synthesis example 2
After 106 g of p-acetoxystyrene, 42 g of pt-butoxystyrene, 5 g of styrene, 6 g of azobisisobutyronitrile and 1 g of t-dodecyl mercaptan were dissolved in 160 g of propylene glycol monomethyl ether, the reaction temperature was 70 under a nitrogen atmosphere. The polymerization was carried out for 16 hours while maintaining the temperature. After the polymerization, the reaction solution was dropped into a large amount of n-hexane to coagulate and purify the resulting copolymer.
Next, 150 g of propylene glycol monomethyl ether was added to the copolymer, and then 300 g of methanol, 80 g of triethylamine, and 15 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in acetone, then dripped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.
The obtained copolymer had Mw of 16,000 and Mw / Mn of 1.7. As a result of ¹³ C-NMR analysis, p-hydroxystyrene and p-t represented by the following formula (A-6) were obtained. -The copolymerization molar ratio of butoxystyrene and styrene was 72: 23: 5. This copolymer is referred to as “resin (A-6)”.

Reference synthesis example 3
After 106 g of pt-butoxystyrene, 4 g of azobisisobutyronitrile and 0.6 g of t-dodecyl mercaptan were dissolved in 110 g of propylene glycol monomethyl ether, the reaction temperature was maintained at 70 ° C. in a nitrogen atmosphere. Polymerized for hours. After the polymerization, the reaction solution was dropped into a large amount of n-hexane, and the resulting polymer was coagulated and purified. The obtained polymer was dissolved in acetone, dropped into a large amount of water to solidify, and the resulting white powder was filtered and dried overnight at 50 ° C. under reduced pressure. The obtained polymer had Mw of 13,000 and Mw / Mn of 1.8.
Next, this poly (pt-butoxystyrene) was dissolved in 600 g of dioxane, diluted hydrochloric acid was added, and a hydrolysis reaction was carried out at 70 ° C. for 2 hours. Coalescence was obtained. Thereafter, this polymer was dissolved in acetone and the operation of coagulating in a large amount of water was repeated, and then the produced white powder was filtered and dried overnight at 50 ° C. under reduced pressure.
Next, 25 g of the obtained poly (p-hydroxystyrene) was dissolved in 100 g of n-butyl acetate, bubbled with nitrogen gas for 30 minutes, 3.4 g of ethyl vinyl ether was added, and pyridinium p-toluenesulfonate as a catalyst. 1 g of salt was added and reacted at room temperature for 12 hours. Thereafter, the reaction solution was dropped into a 1 wt% aqueous ammonia solution to solidify the polymer, filtered, and dried overnight at 50 ° C. under reduced pressure.
As a result of ¹ H-NMR analysis, the obtained polymer is represented by the following formula (A-7). 20 mol% of the hydrogen atoms of the phenolic hydroxyl group in poly (p-hydroxystyrene) are ethoxyxyethyl groups. It had a substituted structure. This copolymer is referred to as “resin (A-7)”.

Reference synthesis example 4
25 g of a 90:10 molar ratio of p-hydroxystyrene and pt-butoxystyrene copolymer (Nippon Soda VPT1503S) was dissolved in 100 g of n-butyl acetate and bubbled with nitrogen gas for 30 minutes. Ethyl vinyl ether (3.3 g) was added, and 1 g of p-toluenesulfonic acid pyridinium salt was added as a catalyst, followed by reaction at room temperature for 12 hours. Thereafter, the reaction solution was dropped into a 1 wt% aqueous ammonia solution to precipitate the resin, filtered, and dried overnight in a vacuum dryer at 50 ° C.
The obtained resin had Mw of 13,000 and Mw / Mn of 1.01, and as a result of ¹³ C-NMR analysis, poly (p-hydroxystyrene) represented by the following formula (A-8) was 67 mol. %, A copolymer in which the hydrogen atom of the phenolic hydroxyl group was substituted by 23 mol% and pt-butoxystyrene was 10 mol%. This copolymer is referred to as “resin (A-8)”.

Reference synthesis example 5
After dissolving 104 g of p-acetoxystyrene, 42 g of 1-ethylcyclopentyl methacrylate, 90 g of indene, 6 g of azobisisobutyronitrile and 1 g of t-dodecyl mercaptan in 160 g of propylene glycol monomethyl ether, the reaction temperature is 70 ° C. in a nitrogen atmosphere. And polymerized for 16 hours. After the polymerization, the reaction solution was dropped into a large amount of n-hexane to coagulate and purify the resulting copolymer.
Next, 150 g of propylene glycol monomethyl ether was added to the copolymer, and then 300 g of methanol, 80 g of triethylamine, and 15 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in acetone, then dripped into a large amount of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight.
The obtained copolymer had an Mw of 11,000 and an Mw / Mn of 2.0. As a result of ¹³ C-NMR analysis, a copolymerization molar ratio of p-hydroxystyrene, 1-ethylcyclopentyl methacrylate and indene was obtained. Was 60:23:17. This copolymer is referred to as “resin (A-9)”.

Examples 5 to 12 and Comparative Example 1
The components shown in Table 1 (where parts are based on weight) were mixed in the amounts shown in Table 1 to obtain a uniform solution, and then filtered through a membrane filter having a pore size of 200 nm to prepare a composition solution. The following operations were performed in a clean truck ACT-8 manufactured by Tokyo Electron. The composition solution was spin-coated on a silicon wafer spin-coated with Nissan Chemical Co. DUV42 at 60 nm and baked at 190 ° C. for 60 seconds, and then PB was performed under the conditions shown in Table 2 to obtain a film thickness. A 270 nm resist film was formed.
Next, using a Nikon scanner NSR-S203B (numerical aperture 0.68, σ 0.75, 2/3 annular illumination), using an 8% halftone mask, the conditions shown in Table 2 were obtained. PEB was performed. Thereafter, a 2.38 wt% tetramethylammonium hydroxide aqueous solution was used and developed by a paddle method using an E3 nozzle at 23 ° C. for 30 seconds, followed by washing with pure water and drying to form a resist pattern. Table 2 shows the evaluation results of each resist.

The acid generator (B), acid diffusion controller (C) and solvent (D) in Table 1 are as follows.
Acid generator (B):
B-1: Diphenyliodonium 10-camphorsulfonate B-2: Diphenyliodonium trifluoromethanesulfonate B-3: N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-di Carboximide B-4: Bis (cyclohexylsulfonyl) diazomethane B-5: Bis (t-butylsulfonyl) diazomethane B-6: Triphenylsulfonium trifluoromethanesulfonate diffusion control agent (C):
C-1: tri-n-octylamine C-2: triethanolamine C-3: 2-phenylpyridine C-4: 2-phenylbenzimidazole solvent (D):
D-1: Ethyl lactate D-2: Ethyl 3-ethoxypropionate D-3: Propylene glycol monomethyl ether acetate

Here, each resist was evaluated in the following manner.
(1) Sensitivity:
The resist film formed on the silicon wafer is exposed to light, immediately subjected to PEB, then developed with alkali, washed with water and dried to form a resist pattern. When a resist pattern is formed, a line width of 160 nm, a line and space pattern (1L1S) The exposure amount for forming a line width of 1: 1 was set as the optimum exposure amount, and the sensitivity was evaluated based on the optimum exposure amount.
(2) Resolution:
The minimum dimension (nm) of the line and space pattern (1L1S) resolved when exposed at the optimum exposure amount was defined as the resolution.
(3) Line end foreshortening (LEF):
A 116 nm line and space pattern (1L1S) was exposed with an optimal exposure amount, and observed with a scanning electron microscope. The observation results are shown in FIG. The length (a) of the white portion at the tip was measured, and the average value of the center of the 25 lines was taken as the LEF value.

The radiation-sensitive resin composition of the present invention is a chemically amplified resist that is sensitive to actinic radiation such as KrF excimer laser, ArF excimer laser, or F ₂ excimer laser, and has high resolution and line end foreshortening resistance. An excellent radiation-sensitive resin composition can be provided, and can be used very suitably in the field of microfabrication represented by the manufacture of integrated circuit elements that are expected to become increasingly finer in the future.

It is a schematic diagram of a line pattern. It is a scanning electron micrograph of a line pattern.

Explanation of symbols

1 Substrate 2 Resist pattern

Claims (3)

The weight average molecular weight in terms of polystyrene measured by gel permeation chromatography is 3,000 to 100,000, including repeating units represented by the following formula (1), formula (2) and formula (3), respectively. A featured copolymer.
(In Formula (1), Formula (2) and Formula (3), R ¹ and R ³ represent a hydrogen atom or a methyl group, R ² represents a monovalent organic group, and R ⁴ has a substituent. Represents an acid-dissociable group containing a tricyclodecanyl group or the same tetracyclododecenyl group, and R ⁵ and R ⁶ are a hydrogen atom, a hydroxy group, a substituted hydroxyalkyl group, linear or branched Represents an alkyl group, a substituted alkoxyl group, or a halogen atom, q is an integer of 1 to 3, p is an integer of 0 to 2, and t is an integer of 0 to 4.) A radiation-sensitive resin composition comprising an acid-dissociable group-containing resin (A) that is insoluble in alkali or hardly soluble in alkali and easily soluble in alkali by the action of an acid, and a radiation-sensitive acid generator (B). And
The radiation-sensitive resin composition, wherein the acid-dissociable group-containing resin (A) is the copolymer according to claim 1. The radiation sensitive resin composition according to claim 2, wherein the radiation sensitive acid generator (B) is at least one compound selected from a diazomethane compound and a sulfonium salt.