JPWO2006043597A1 - Radiation sensitive resin composition - Google Patents

Abstract

It becomes a water-stable film during immersion exposure and satisfies the depth of focus margin. A radiation-sensitive resin composition used for immersion exposure in which water is irradiated between a lens and a photoresist film through water, the resin component comprising a resin component and an acid generator, wherein the resin component is a hydroxystyrene unit and It is a polymer containing a repeating unit containing an acid dissociable group-containing component, and the hydroxystyrene unit is contained in an amount of 5 to 65 mol% based on all repeating units constituting the polymer, and the hydroxystyrene unit is represented by the following formula: It is represented by (1). R1 represents a hydrogen atom or a methyl group, R2 represents a hydrogen atom or a monovalent organic group, k and l are each an integer of 1 to 3, and k + 1 = 5.

Description

  The present invention relates to a radiation-sensitive resin composition, and particularly to a radiation-sensitive resin composition used for immersion exposure used for lithography miniaturization.

Stepper-type or step-and-scan type projection exposure apparatus that transfers a reticle pattern as a photomask to each shot area on a wafer coated with a photoresist via a projection optical system when manufacturing a semiconductor element or the like Is used.
The resolution of the projection optical system provided in the projection exposure apparatus becomes higher as the exposure wavelength used is shorter and the numerical aperture of the projection optical system is larger. For this reason, with the miniaturization of integrated circuits, the exposure wavelength, which is the wavelength of radiation used in the projection exposure apparatus, has become shorter year by year, and the numerical aperture of the projection optical system has also increased.
Further, when performing exposure, the depth of focus is important as well as the resolution. The resolution R and the depth of focus δ are each expressed by the following equations.
R = k1 · λ / NA (i)
δ = k ² · λ / NA ² (ii)
Here, λ is the exposure wavelength, NA is the numerical aperture of the projection optical system, and k1 and k2 are process coefficients. In order to obtain the same resolution R, a larger depth of focus δ can be obtained by using radiation having a short wavelength.

In this case, a photoresist film is formed on the exposed wafer surface, and the pattern is transferred to the photoresist film. In the conventional projection exposure apparatus, the space in which the wafer is placed is filled with air or nitrogen. At this time, when the space between the wafer and the lens of the projection exposure apparatus is filled with a medium having a refractive index n, the resolution R and the depth of focus δ are expressed by the following equations.
R = k1 · (λ / n) / NA (iii)
δ = k2 · nλ / NA ² (iv)
For example, in the KrF process, when water is used as the medium, the refractive index n = 1.44 of light having a wavelength of 248 nm is used, and the resolution R is 69.compared to the exposure using air or nitrogen as the medium. 4% (R = k1 · (λ / 1.44) / NA) and the focal depth is 144% (δ = k2 · 1.44λ / NA ² ).
A projection exposure method capable of shortening the wavelength of radiation for exposure and transferring a finer pattern is called immersion exposure, which is an essential technique for miniaturization of lithography, particularly lithography of several tens of nanometers. The projection exposure apparatus is also known (see Patent Document 1).
In the immersion exposure method, a photoresist film formed by applying a radiation-sensitive resin composition on a wafer and a lens of a projection exposure apparatus are in contact with water. Therefore, water may penetrate into the photoresist film and the resolution of the photoresist may be reduced. In addition, there is a problem such as contamination of the lens surface due to elution of the constituent components of the photoresist into water.
For this reason, the photoresist film is required to have film properties that maintain a water-stable film without being eluted in water during immersion exposure and that can be easily dissolved in an alkaline solution as a developer.
In addition, as the miniaturization of the photolithography process proceeds rapidly, the characteristic requirements required for photoresists are becoming increasingly severe. In addition to the improvement of the conventional resolution performance and the line edge roughness, the improvement of the depth of focus margin (process margin) is also demanded.
However, a radiation-sensitive resin composition for forming a photoresist film that becomes a water-stable film at the time of immersion exposure and that satisfies excellent resolution performance and depth of focus margin has not been obtained.
Japanese Patent Laid-Open No. 11-176727

  The present invention has been made to cope with such problems, and provides a radiation-sensitive resin composition that becomes a water-stable film during immersion exposure and satisfies excellent resolution performance and depth of focus margin. Objective.

式（１）において、Ｒ^１は水素原子またはメチル基を表し、Ｒ^２は水素原子または１価の有機基を表し、ｋおよびｌはそれぞれ１〜３の整数であり、かつｋ＋ｌ＝５である。
また、上記酸解離性基含有成分を含む繰返し単位が下記式（２）で表されることを特徴とする。

式（２）において、Ｒ^３は水素原子またはメチル基を表し、Ｒ^４、Ｒ^５およびＲ^６はそれぞれ炭素数１〜４の飽和炭化水素基を表す。The radiation-sensitive resin composition of the present invention is a radiation-sensitive resin composition that is used for immersion exposure in which radiation is irradiated between water between a lens and a photoresist film, and includes a resin component and an acid generator. The resin component is a polymer containing a repeating unit containing a hydroxystyrene unit and an acid dissociable group-containing component, and the hydroxystyrene unit is 5 to 65 with respect to all repeating units constituting the polymer. It is characterized by containing mol%.
The hydroxystyrene unit is represented by the following formula (1).

In the formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a monovalent organic group, k and l are each an integer of 1 to 3, and k + 1 = 5 .
Moreover, the repeating unit containing the said acid dissociable group containing component is represented by following formula (2), It is characterized by the above-mentioned.

In Formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ , R ^5, and R ⁶ each represent a saturated hydrocarbon group having 1 to 4 carbon atoms.

The acid generator contained in the radiation-sensitive resin composition of the present invention contains at least one acid generator selected from a nonionic acid generator and an onium salt compound containing a fluorine atom.
The nonionic acid generator has a solubility in water at 25 ° C. of 1 g / 100 ml H ₂ O or less.
The nonionic acid generator is at least one compound selected from a sulfonimide compound and a disulfonyldiazomethane compound.
The acid generator is an onium salt compound containing the nonionic acid generator and a fluorine atom, and 50 wt% of the onium salt containing a fluorine atom with respect to 100 parts by weight of the nonionic acid generator. It is characterized by including the following parts.
Another radiation-sensitive resin composition of the present invention is used in immersion exposure in which radiation is irradiated between water between a lens and a photoresist film, and includes a resin component and an acid generator. The acid generator includes a nonionic acid generator having a solubility in water at 25 ° C. of 1 g / 100 ml H ₂ O or less.
And

Since the radiation-sensitive resin composition for immersion exposure according to the present invention contains 5 to 65 mol% of hydroxystyrene units as a resin component, the affinity for water is reduced when a resist film is formed. Therefore, it becomes a water-stable resist film at the time of immersion exposure, there is no variation in film thickness, and the focus depth margin is excellent. Further, by using a stepper type or step-and-scan projection exposure apparatus using a KrF excimer laser, the photolithography process can be further miniaturized.
Further, the acid generator includes at least one acid generator selected from a nonionic acid generator and an onium salt compound containing a fluorine atom, and the nonionic acid generator has a solubility in water at 25 ° C. of 1 g / since in 100 ml H 2 _O or less, it is possible to increase the hydrophobicity can be provided a radiation-sensitive resin composition excellent in resolution and immersion resistance.

The resin component of this invention contains 5-65 mol% of hydroxy styrene units with respect to all the repeating units which comprise a resin component. In the present invention, the hydroxystyrene unit is a unit obtained from hydroxystyrene and a hydroxystyrene derivative, and is a repeating unit represented by the above formula (1).
In the formula (1), R ² represents a hydrogen atom or a monovalent organic group. Examples of the monovalent organic group include carbon number such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, and t-butyl group. 1-12 linear or branched alkyl groups; methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy A linear or branched alkoxyl group having 1 to 12 carbon atoms such as a group; a linear or branched alkyl halide group having 1 to 12 carbon atoms; a linear or branched group having 1 to 12 carbon atoms And halogenated alkoxyl groups. Among these, a methyl group, an ethyl group, an n-butyl group, and a t-butyl group are preferable.
The repeating unit represented by the formula (1) can be obtained by using the corresponding hydroxystyrene derivative as a monomer.
Examples of preferable monomers that generate the repeating unit represented by the formula (1) include o-hydroxystyrene, m-hydroxystyrene, 4-hydroxystyrene, 2-methyl-3-hydroxy. Styrene, 4-methyl-3-hydroxystyrene, 5-methyl-3-hydroxystyrene, 2-methyl-4-hydroxystyrene, 3-methyl-4-hydroxystyrene, 3,4-dihydroxystyrene, 2,4,6 -Trihydroxystyrene etc. are mentioned. Of these, 4-hydroxystyrene is preferred.
The repeating unit represented by the formula (1) can be present alone or in combination of two or more.

The resin component of this invention contains the repeating unit containing an acid dissociable group containing component with a hydroxystyrene unit.
The acid-dissociable group-containing component can be used as long as it is insoluble in alkali or hardly soluble in alkali and imparts a property that becomes easily soluble in alkali by the action of an acid to the resin component. A suitable acid-dissociable group-containing component is a repeating unit represented by the above formula (2).
In the formula (2), R ⁴ , R ⁵ and R ⁶ each represent a saturated hydrocarbon group having 1 to 4 carbon atoms. Examples of the saturated hydrocarbon group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, and t-butyl group. Is mentioned.
The repeating unit represented by the formula (2) can be obtained by using the corresponding hydroxystyrene derivative as a monomer.
Examples of preferred monomers that generate the repeating unit represented by the formula (2) include 4-t-butoxystyrene, 4-t-butoxy-α-methylstyrene, 4- (2 -Ethyl-2-propoxy) styrene, 4- (2-ethyl-2-propoxy) -α-methylstyrene and the like. Of these, 4-t-butoxystyrene is preferred.
The repeating unit represented by the formula (2) can be present alone or in combination of two or more.

The resin component of the present invention can further contain other repeating units shown below.
Other repeating units include, for example, i-propyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, cyclopentyl (meth) acrylate, 1-methylcyclopentyl (meth) acrylate, 1- Ethylcyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, 1-methylcyclohexyl (meth) acrylate, 1-ethylcyclohexyl (meth) acrylate, benzyl (meth) acrylate, norbornyl (meth) acrylate, isonorbornyl (meth) acrylate, tri Cyclodecanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, adamantane-1-yl (meth) acrylate, 2-methyladamantan-2-yl (meth) acrylate (Meth) acrylic acid ester-based units in which polymerizable unsaturated bonds such as 2-ethyladamantan-2-yl (meth) acrylate, tetrahydrofuranyl (meth) acrylate, and tetrahydropyranyl (meth) acrylate are cleaved; t-butoxy Polymerizable unsaturated bonds such as carbonyloxystyrene, 4-t-butoxycarbonylmethyloxystyrene, 4- (2-t-butoxycarbonylethyloxy) styrene, 4-tetrahydrofuranyloxystyrene, 4-tetrahydropyranyloxystyrene, etc. In addition to units containing acid-dissociable groups such as cleaved vinyl aromatic units,

  Styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, 4-methyl styrene, o-hydroxy-α-methyl styrene, m-hydroxy-α-methyl styrene, 4-hydroxy-α-methyl styrene, o -Vinyl aromatic compounds such as methoxystyrene, m-methoxystyrene, 4-methoxystyrene; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, i- Butyl (meth) acrylate, n-pentyl (meth) acrylate, neopentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl ( (Meth) acrylate, - hydroxypropyl (meth) acrylate, adamantylmethyl (meth) acrylate, phenyl (meth) acrylate, phenethyl (meth) acrylate,

（式中ｎは１〜６の整数を表す）Monomers represented by the following formulas (3) to (5),

(Wherein n represents an integer of 1 to 6)

（式（６）において、Ｒ^７は水素原子またはメチル基を表し、Ｒ^８は相互に独立に水素原子または炭素数１〜４の飽和炭化水素基を表す。）
不飽和アミド化合物の具体例としては、Ｎ，Ｎ’−ジメチル（メタ）アクリルアミド、Ｎ，Ｎ’−ジエチル（メタ）アクリルアミド等が挙げられる。An unsaturated amide compound represented by the following formula (6):

(In Formula (6), R ⁷ represents a hydrogen atom or a methyl group, and R ⁸ independently represents a hydrogen atom or a saturated hydrocarbon group having 1 to 4 carbon atoms.)
Specific examples of the unsaturated amide compound include N, N′-dimethyl (meth) acrylamide, N, N′-diethyl (meth) acrylamide and the like.

In addition, unsaturated carboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid and cinnamic acid; unsaturated polycarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; (meth) acrylic Carboxyalkyl esters of unsaturated carboxylic acids such as 2-carboxyethyl acid, 2-carboxypropyl (meth) acrylate, 3-carboxypropyl (meth) acrylate; (meth) acrylonitrile, α-chloroacrylonitrile, crotonnitrile, Unsaturated nitrile compounds such as malein nitrile and fumaronitrile; unsaturated imide compounds such as maleimide, N-phenylmaleimide and N-cyclohexylmaleimide; N-vinyl-ε-caprolactam, N-vinylpyrrolidone, 2-vinylpyridine, 3-vinylpyridine 4-vinyl pyridine, 2-vinyl Examples thereof include a unit in which a polymerizable unsaturated bond is cleaved, such as other nitrogen-containing vinyl compounds such as ruimidazole and 4-vinylimidazole.
Among these other repeating units, a unit in which a polymerizable unsaturated bond such as styrene, α-methylstyrene, or a monomer represented by the above formulas (3) and (6) is cleaved is preferable. These other repeating units can be used alone or in admixture of two or more.

The resin component constituting the radiation-sensitive resin composition for immersion exposure of the present invention contains a repeating unit including a hydroxystyrene unit and an acid-dissociable group-containing component. A hydroxystyrene unit is 5-65 mol% with respect to all the repeating units which comprise a resin component, Preferably it is 10-65 mol%, More preferably, it is 15-65 mol%. Within this range, the value (a / b) for evaluating the immersion resistance described later tends to be 0.9 to 1.1.
The repeating unit containing an acid dissociable group-containing component is 75 mol% or less based on all repeating units constituting the resin component. If it exceeds 75 mol%, the immersion resistance described later tends to deteriorate. Further, the repeating unit represented by the formula (2) is preferably 20 mol% or more in order to improve the resolution.

For example, the polymer may be a mixture of monomers that generate each repeating unit, using radical polymerization initiators such as hydroperoxides, dialkyl peroxides, diacyl peroxides, and azo compounds, if necessary. In the presence of a chain transfer agent in a suitable solvent. Examples of the solvent used for the polymerization include cycloalkanes such as cyclohexane and cycloheptane; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate, and propylene glycol monomethyl ether acetate. Alkyl lactones such as γ-butyrolactone; ethers such as tetrahydrofuran, dimethoxyethanes and diethoxyethanes; alkyl ketones such as 2-butanone, 2-heptanone and methyl isobutyl ketone; cycloalkyl ketones such as cyclohexanone And alcohols such as 2-propanol and propylene glycol monomethyl ether. These solvents can be used alone or in admixture of two or more.
Moreover, the reaction temperature in the said superposition | polymerization is 40-120 degreeC normally, Preferably it is 50-100 degreeC, and reaction time is 1-48 hours normally, Preferably it is 1-24 hours.

The polystyrene-converted weight average molecular weight (hereinafter also referred to as “Mw”) of each polymer measured by gel permeation chromatography (GPC) is preferably 1,000 to 150,000, more preferably 3,000 to 100. The ratio (Mw / Mn) of Mw and the polystyrene-equivalent number average molecular weight (hereinafter also referred to as “Mn”) measured by GPC is usually 1 to 5.
The polymer can be used as a resin component constituting a radiation-sensitive resin composition for immersion exposure that is insoluble in alkali or hardly soluble in alkali and easily soluble in alkali by the action of an acid.

上記式（７）において、Ｒ^１０は１価の有機基を表し、Ｒ^９は２価の有機基を表す。
１価の有機基としては、置換もしくは非置換の直鎖または分岐アルキル基、置換もしくは非置換の環式アルキル基、置換もしくは非置換のアリール基、パーフルオロアルキル基等が、２価の有機基としては、置換もしくは非置換のアルキレン基、置換もしくは非置換のアルケニレン基、置換もしくは非置換のフェニレン基等が挙げられる。The acid generator that can be used in the radiation-sensitive resin composition of the present invention is a radiation-sensitive acid generator that generates an acid upon exposure. Examples of the acid generator include (1) sulfonimide compound, (2) disulfonylmethane compound, (3) sulfone compound, (4) sulfonic acid ester compound, (5) disulfonyldiazomethane compound, (6) onium salt compound, and the like. Is mentioned.
Examples of these acid generators are shown below.
(1) Sulfonimide compound As a sulfonimide compound, it represents with following formula (7), for example.

In the above formula (7), R ¹⁰ represents a monovalent organic group, and R ⁹ 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- (4-toluenesulfonyloxy) succinimide, N- (4-toluenesulfonyloxy) bicyclo [ 2.2.1] Hept-5-ene-2,3-dicarboximide, N- (4-trifluoro) Methylbenzenesulfonyloxy) 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- (nonafluorobutyl Sulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (perfluorooctanesulfonyloxy) succinimide, N- (perfluorooctanesulfonyloxy) bicyclo [2.2 .1] Hept-5-ene-2,3-di Ruboxyimide, N- (benzenesulfonyloxy) 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) sulfonyl And oxy} succinimide.

  Among the sulfonamides, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (10-camphorsulfonyloxy) succinimide, N -(4-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.

式中、Ｒ^１１およびＲ^１２は相互に独立に直鎖状もしくは分岐状の１価の脂肪族炭化水素基、シクロアルキル基、アリール基、アラルキル基またはヘテロ原子を有する１価の他の有機基を表し、ＸおよびＹは相互に独立にアリール基、水素原子、直鎖状もしくは分岐状の１価の脂肪族炭化水素基またはヘテロ原子を有する１価の他の有機基を表し、かつＸおよびＹの少なくとも一方がアリール基であるか、もしくはＸとＹが相互に連結して少なくとも１個の不飽和結合を有する単環または多環を形成しているか、もしくはＸとＹが相互に連結して下記式（８−１）で表される基を形成している。

ただし、Ｘ’およびＹ’は相互に独立に水素原子、ハロゲン原子、直鎖状もしくは分岐状のアルキル基、シクロアルキル基、アリール基またはアラルキル基を示すか、もしくは同一のもしくは異なる炭素原子に結合したＸ’とＹ’が相互に連結して炭素単環構造を形成しており、複数存在するＸ’およびＹ’はそれぞれ相互に同一でも異なってもよく、ｒは２〜１０の整数である。(2) As a disulfonylmethane compound, it represents with following formula (8), for example.

In the formula, R ¹¹ and R ¹² 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 (8-1) 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) 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.

(4) 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.

式中、Ｒ^１３およびＲ^１４は相互に独立にアルキル基、アリール基、ハロゲン置換アルキル基、ハロゲン置換アリール基等の１価の基を示す。(5) Disulfonyldiazomethane compound Examples of the disulfonyldiazomethane compound include a compound represented by the following formula (9).

In the formula, R ¹³ and R ¹⁴ 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 the disulfonyldiazomethane compound include bis (trifluoromethanesulfonyl) diazomethane, bis (cyclohexanesulfonyl) diazomethane, bis (benzenesulfonyl) diazomethane, bis (4-toluenesulfonyl) diazomethane, methanesulfonyl-4-toluenesulfonyldiazomethane, Cyclohexanesulfonyl-1,1-dimethylethylsulfonyldiazomethane, bis (1,1-dimethylethanesulfonyl) diazomethane, bis (3,3-dimethyl-1,5-dioxaspiro [5.5] dodecan-8-sulfonyl) diazomethane, Bis (1,4-dioxaspiro [4.5] decan-7-sulfonyl) diazomethane, bis (t-butylsulfonyl) diazomethane, and the like can be given.

(6) Onium salt compound Examples of the onium salt compound include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, ammonium salts, pyridinium salts, and the like.
In the present invention, among the onium salt compounds, fluorine atom-containing onium salts are preferred.
Examples of the fluorine atom-containing onium salt include compounds containing a fluorine atom in the molecular structure such as the iodonium salt. The fluorine atom may be contained in the cation part of the onium salt, in the anion part, or in both the cation part and the anion part.

Ｒｆはフッ素原子、パーフルオロアリール基またはパーフルオロアルキル基を表す。パーフルオロアリール基またはパーフルオロアルキル基としては、炭素数１〜６のパーフルオロアルキル基、炭素数６〜１０のパーフルオロシクロアルキル基、炭素数６〜１０のパーフルオロアリール基が挙げられ、具体的には、トリフルオロメチル基、ノナフルオロブチル基、またはパーフルオロシクロヘキシル基、パーフルオロフェニル基が例示できる。Ｒはフッ素原子を含まない１価の有機基を表す。１価の有機基としては、直鎖状または分岐状のアルキル基、置換または非置換のアリール基、アラルキル基、または環状のアルキル基が挙げられる。好ましい基としては、シクロヘキシル基、シクロペンチル基、ノルボルニル基、トリシクロデカニル基、テトラシクロドデシル基または１０−カンホロイル基が挙げられる。The anion portion of the onium salt containing a fluorine atom is represented by the following formula (10) or formula (11).

Rf represents a fluorine atom, a perfluoroaryl group or a perfluoroalkyl group. Examples of the perfluoroaryl group or perfluoroalkyl group include a C 1-6 perfluoroalkyl group, a C 6-10 perfluorocycloalkyl group, and a C 6-10 perfluoroaryl group. Specifically, a trifluoromethyl group, a nonafluorobutyl group, a perfluorocyclohexyl group, and a perfluorophenyl group can be exemplified. R represents a monovalent organic group containing no fluorine atom. Examples of the monovalent organic group include a linear or branched alkyl group, a substituted or unsubstituted aryl group, an aralkyl group, and a cyclic alkyl group. Preferable groups include a cyclohexyl group, a cyclopentyl group, a norbornyl group, a tricyclodecanyl group, a tetracyclododecyl group, or a 10-camphoroyl group.

  The cation moiety of the onium salt containing a fluorine atom contains at least one fluorine atom. Examples of the cation moiety include cation moieties such as the sulfonium salt, iodonium salt, phosphonium salt, diazonium salt, ammonium salt, pyridinium salt compound, etc., and the fluorine atom replaces the hydrogen atom of these hydrocarbon groups, or is aromatic. It is directly bonded to an aromatic ring or alicyclic ring.

  Examples of fluorine atom-containing onium salt compounds include triphenylsulfonium nonafluorobutanesulfonate, tris (4-fluorophenyl) sulfonium 10-camphorsulfonate, triphenylsulfonium 2- (2-norbornyl) 1,1,2,2-tetrafluoro. Ethyl sulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium perfluorooctane sulfonate, triphenylsulfonium 4-trifluoromethylbenzenesulfonate, triphenylsulfonium perfluorobenzenesulfonate, triphenylsulfonium 2,4-difluorobenzenesulfonate, 4- Hydroxyphenyl diphenylsulfonium trifluoromethanesulfonate, tri (4-methoxy Enyl) sulfonium nonafluorobutanesulfonate, tri (4-methoxyphenyl) sulfonium trifluoromethanesulfonate, tri (4-methoxyphenyl) sulfonium perfluorooctanesulfonate, tri (4-methoxyphenyl) sulfonium 4-toluenesulfonate, tri (4- Methoxyphenyl) sulfonium benzenesulfonate, tris (4-fluorophenyl) sulfonium trifluoromethanesulfonate, tris (4-fluorophenyl) sulfonium 4-toluenesulfonate, (4-fluorophenyl) diphenylsulfonium trifluoromethanesulfonate, bis (4-fluorophenyl) ) Iodonium 1,1,2,2-tetrafluoroethyl sulfonate, bis (4-t-butylphenyl) Iodonium nonafluorobutanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium perfluorooctanesulfonate, 4-trifluoromethylbenzenesulfonate, bis (4-t-butyl) Phenyl) iodonium perfluorobenzenesulfonate, diphenyliodonium nonafluorobutanesulfonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium perfluorooctanesulfonate, (4-fluorophenyl) (phenyl) iodonium trifluoromethanesulfonate, 2,4,6-trimethylphenyl Diphenylsulfonium 4-trifluoromethylbenzenesulfonate, 2,4,6- Examples include trimethylphenyldiphenylsulfonium 2,4-difluorobenzenesulfonate.

  Among the fluorine atom-containing onium salt compounds, triphenylsulfonium 2 (2-norbornyl) 1,1,2,2 may be used as the onium salt compound containing an anion moiety represented by formula (10) or formula (11). Tetrafluoroethyl sulfonate, triphenylsulfonium 2,4-difluorobenzene sulfonate, or bis (4-fluorophenyl) iodonium 1,1,2,2-tetrafluoroethyl sulfonate, 2,4,6-trimethylphenyl diphenylsulfonium 4 -Trifluoromethylbenzenesulfonate, 2,4,6-trimethylphenyldiphenylsulfonium 2,4-difluorobenzenesulfonate are preferred.

  Examples of onium salt compounds other than fluorine atom-containing onium salt compounds include bis (4-tert-butylphenyl) iodonium 4-toluenesulfonate, bis (4-tert-butylphenyl) iodonium 10-camphor sulfonate, and diphenyliodonium 4-toluenesulfonate. , Diphenyliodonium benzenesulfonate, diphenyliodonium 10-camphorsulfonate, triphenylsulfonium 4-toluenesulfonate, triphenylsulfoniumbenzenesulfonate, triphenylsulfonium 10-camphorsulfonate, tri (4-methoxyphenyl) sulfonium 4-toluenesulfonate, tri ( 4-methoxyphenyl) sulfonium benzenesulfonate, tri (4-methoxyphenyl) sulfonium 1 - camphorsulfonate, and the like.

Among the acid generators, the nonionic acid generator has a solubility in water at 25 ° C. of 1 g / 100 ml H ₂ O or less. When the solubility exceeds 1 g / 100 ml H ₂ O, the hydrophobicity during immersion exposure is poor.
Examples of the nonionic acid generator include the sulfonimide compound, the disulfonylmethane compound, the sulfone compound, the sulfonic acid ester compound, and the disulfonyldiazomethane compound.
Among these nonionic acid generators, a sulfonimide compound, a disulfonyldiazomethane compound, or a mixture of a sulfonimide compound and a disulfonyldiazomethane compound is preferable. These acid generators can form a water-stable film during immersion exposure.
In the present invention, a fluorine atom-containing onium salt can be used alone or as a mixed acid generator as an acid generator.

When the mixed acid generator is used, it is preferable that the nonionic acid generator exceeds 50 mol% in the mixed acid generator, and the sulfonimide compound in the whole nonionic acid generator. The disulfonyldiazomethane compound or the mixture of the sulfonimide compound and the disulfonyldiazomethane compound is preferably contained in an amount of 50 mol% or more.
Moreover, the acid generator containing a fluorine atom containing onium salt can be used with the said nonionic acid generator. The fluorine atom-containing onium salt is contained in an amount of 50 parts by weight or less, preferably 5 to 50 parts by weight, based on 100 parts by weight of the nonionic acid generator.

In the present invention, the amount of the acid generator used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 15 parts by weight, and further preferably 1 to 15 parts by weight with respect to 100 parts by weight of the resin component. Part by weight is added. When the addition amount is 0.1 parts by weight or less, the effect of the present invention tends to hardly appear, and when the addition amount exceeds 20 parts by weight, the heat resistance as the radiation-sensitive resin composition tends to decrease.
In the present invention, two or more acid generators can be mixed and used.

式中、Ｒ^１５は、相互に同一でも異なってもよく、水素原子、アルキル基、アリール基またはアラルキル基（アルキル基、アリール基、アラルキル基等の水素原子が、例えば、ヒドロキシ基など、官能基で置換されている場合を含む。The radiation-sensitive resin composition of the present invention can contain an acid diffusion controller and other additives.
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.
Examples of such a nitrogen-containing organic compound include a compound represented by the following formula (12) (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 ¹⁵ may be the same as or different from each other, and a hydrogen atom such as a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group (an alkyl group, an aryl group, an aralkyl group, etc. is a functional group such as a hydroxy group, for example). Including the case where it is replaced with.

  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 Ruanirin, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, aromatic amines such as 1-naphthylamine, and the like.

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-bis [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 the urea compound 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.

式（１３）において、各Ｒ^１６は、相互に独立に１価の有機基を表すか、あるいは２つのＲ^１６が相互に結合して式中の窒素原子と共に環を形成している。
具体的にはＮ−（ｔ−ブトキシカルボニル）ピペリジン、Ｎ−（ｔ−ブトキシカルボニル）イミダゾール、Ｎ−（ｔ−ブトキシカルボニル）ベンズイミダゾール、Ｎ−（ｔ−ブトキシカルボニル）２−フェニルベンズイミダゾール、Ｎ−（ｔ−ブトキシカルボニル）ジオクチルアミン、Ｎ−（ｔ−ブトキシカルボニル）ジエタノールアミン、Ｎ−（ｔ−ブトキシカルボニル）ジシクロヘキシルアミン、Ｎ−（ｔ−ブトキシカルボニル）ジフェニルアミン等が挙げられる。As the acid diffusion controller, a base precursor having an acid dissociable group represented by the following formula (13) can also be used.

In the formula (13), each R ¹⁶ independently represents a monovalent organic group, or two R ¹⁶ are bonded to each other to form a ring together with the nitrogen atom in the formula.
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 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. In addition, if the compounding quantity of an acid diffusion control agent is less than 0.001 weight part, there exists a possibility that the pattern shape and dimension fidelity as a resist may fall depending on 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 developability 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. Commercially available products include, for example, 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.), made KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.).
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.

The radiation-sensitive resin composition of the present invention is used after being uniformly dissolved in a solvent so that the total solid content is, for example, 0.1 to 50% by weight, preferably 1 to 40% by weight. For example, it is prepared as a composition solution by filtering with a filter having a pore diameter of about 200 nm.
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 ethers 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-butyrolactone 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 in some cases, a heat treatment (hereinafter referred to as “PB”) is performed at a temperature of about 70 ° C. to 160 ° C. in advance. . Thereafter, the resist film or an upper protective film formed as necessary is irradiated with radiation through a mask having a predetermined pattern using water as a medium, and then developed. The water filled between the lens and the resist film can also adjust the pH. In particular, pure water is preferred.
The radiation used for immersion exposure depends on the resist film used, for example, visible rays; ultraviolet rays such as g rays and i rays; far ultraviolet rays such as excimer lasers; X rays such as synchrotron radiation; Various types of radiation such as charged particle beams can be selectively used. In the present invention, far ultraviolet rays such as KrF excimer laser (wavelength 248 nm) are preferably used.
In order to improve the resolution, pattern shape, developability, etc. of the resist film, it is preferable to perform baking (hereinafter referred to as “PEB”) after exposure. The baking temperature is appropriately adjusted depending on the resist used and the like, but is usually about 30 to 200 ° C, preferably 50 to 150 ° C.
Next, the photoresist film is developed with an alkali developer and washed to form a desired resist pattern.
As an alkaline developer, for example, an alkaline compound such as a tetraalkylammonium hydroxide is usually dissolved in a concentration of 1 to 10% by weight, preferably 1 to 5% by weight, particularly preferably 1 to 3% by weight. Alkaline aqueous solution 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.

Measurement of Mw and Mn of the acid-dissociable group-containing resin obtained by the following Synthesis Examples are, Tosoh Co., Ltd. GPC column (G2000H _XL 2 present, one G3000H _XL, G4000H _XL one) was used, the flow rate 1 Measurement was performed by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under the analysis conditions of 0.0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C.

Synthesis example 1
After dissolving 47 g of 4-acetoxystyrene, 108 g of 4-t-butoxystyrene, 6 g of azobisisobutyronitrile (hereinafter abbreviated as AIBN) and 1 g of t-dodecyl mercaptan in 160 g of propylene glycol monomethyl ether, the mixture was dissolved in a nitrogen atmosphere. The polymerization was carried out for 16 hours 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 resin. Next, 150 g of propylene glycol monomethyl ether was added to the purified resin, 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 resulting resin was dissolved in acetone and then dropped into 2000 g of water to solidify. The resulting white powder was filtered and dried at 50 ° C. under reduced pressure overnight. did.
The obtained resin had Mw of 15,000 and Mw / Mn of 1.6. As a result of ¹³ C-NMR analysis, the copolymerization molar ratio of 4-hydroxystyrene and 4-t-butoxystyrene was 28. : 72. This resin is referred to as “acid-labile group-containing resin (A-1)”.

Synthesis example 2
After dissolving 101 g of 4-acetoxystyrene, 50 g of 4-t-butoxystyrene, 6 g of AIBN and 1.3 g of t-dodecyl mercaptan in 160 g of propylene glycol monomethyl ether, the reaction temperature is maintained at 70 ° C. for 16 hours under a nitrogen atmosphere. Polymerized. After the polymerization, the reaction solution was dropped into 20,000 g of n-hexane to coagulate and purify the resulting resin. Next, 150 g of propylene glycol monomethyl ether was added to the purified resin, 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 resulting resin was dissolved in acetone, then dropped into a large amount of water to solidify, and the resulting white powder was filtered and dried at 50 ° C. under reduced pressure overnight. did.
The obtained resin had Mw of 16,000 and Mw / Mn of 1.7. As a result of ¹³ C-NMR analysis, the copolymerization molar ratio of 4-hydroxystyrene and 4-t-butoxystyrene was 72. : 28. This resin is referred to as “acid-labile group-containing resin (A-2)”.

Synthesis example 3
168 g of 4-acetoxystyrene, 8.3 g of styrene, 84 g of 4-t-butoxystyrene, 10.5 g of AIBN and 1.3 g of t-dodecyl mercaptan are dissolved in 260 g of propylene glycol monomethyl ether, and the reaction temperature is 70 ° C. in a nitrogen atmosphere. And polymerized for 16 hours. After the polymerization, the reaction solution was dropped into 2,000 g of n-hexane to solidify and purify the produced resin, and the resulting purified resin was dried at 50 ° C. under reduced pressure for 3 hours.
Next, 215 g of this purified resin was dissolved again in 260 g of propylene glycol monomethyl ether, and then 300 g of methanol, 80 g of triethylamine and 15 g of water were 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 resulting resin was redissolved in acetone so that the solid content concentration was 20% by weight, and then dropped into 2,000 g of water to coagulate to form a white The powder was filtered and dried overnight at 50 ° C. under reduced pressure. The obtained resin has Mw of 15,500 and Mw / Mn of 1.7. As a result of ¹³ C-NMR analysis, the copolymerization molar ratio of 4-hydroxystyrene, styrene, and 4-t-butoxystyrene is The copolymer was 65: 5: 30. This resin is referred to as “acid-labile group-containing resin (A-3)”.

Synthesis example 4
154 g of 4-acetoxystyrene, 7 g of styrene, 53 g of 4-t-butoxystyrene, 9 g of azobisisobutyronitrile and 1 g of t-dodecyl mercaptan are dissolved in 260 g of propylene glycol monomethyl ether, and the reaction temperature is 70 ° C. in a nitrogen atmosphere. And polymerized for 16 hours. After the polymerization, the reaction solution was dropped into 2,000 g of n-hexane to solidify and purify the produced resin, and the resulting purified resin was dried at 50 ° C. under reduced pressure for 3 hours.
Next, 215 g of this purified resin was dissolved again in 260 g of propylene glycol monomethyl ether, and then 300 g of methanol, 80 g of triethylamine and 15 g of water were 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 resulting resin was redissolved in acetone so that the solid content concentration was 20% by weight, and then dropped into 2,000 g of water to coagulate to form a white The powder was filtered and dried overnight at 50 ° C. under reduced pressure. The obtained resin has Mw of 16,000 and Mw / Mn of 1.7. As a result of ¹³ C-NMR analysis, the copolymerization molar ratio of 4-hydroxystyrene, styrene, and 4-t-butoxystyrene is The copolymer was 72: 5: 23. This resin is referred to as “acid-labile group-containing resin (A-4)”.

Examples 1 to 10 and Comparative Examples 1 to 3
The components shown in Table 1 (where parts are based on weight) were mixed in the amounts shown in Table 1 to obtain a homogeneous solution, and then filtered through a membrane filter having a pore size of 200 nm to prepare a radiation-sensitive resin composition. did.
The acid generator (B), acid diffusion controller (C) and solvent (D) in Table 1 are as follows.
Acid generator (B):
B-1: Triphenylsulfonium 10-camphorsulfonate (solubility in water at 25 ° C., 1 g / 100 ml H ₂ O or less)
B-2: Dicyclohexylsulfonyldiazomethane (solubility in water at 25 ° C., 1 g / 100 ml H ₂ O or less)
B-3: n-trifluoromethanesulfonyloxy-5-norbornene-2,3-dicarboximide (solubility in water at 25 ° C., 1 g / 100 ml H ₂ O or less)
B-4: Tris (4-fluorophenyl) sulfonium trifluoromethanesulfonate (solubility in water at 25 ° C., 1 g / 100 ml H ₂ O or less)
B-5: 2,4,6-trimethylphenyldiphenylsulfonium 4-trifluoromethanebenzenesulfonate (solubility in water at 25 ° C., 1 g / 100 ml H ₂ O or less)
B-6: Diphenyliodonium trifluoromethanesulfonate (solubility in water at 25 ° C., 1 g / 100 ml H ₂ O or less)
Acid diffusion controller (C):
C-1: Tri-n-octylamine C-2: N- (t-butoxycarbonyl) 2-phenylbenzimidazole solvent (D):
D-1: Ethyl lactate D-2: Propylene glycol monomethyl ether acetate

The obtained radiation-sensitive resin composition was evaluated by the immersion resistance, optimum exposure amount, resolution, and depth of focus margin described below. The results are shown in Table 1.
Immersion resistance and sensitivity:
After spin-coating the radiation sensitive resin composition shown in Table 1 on an 8-inch silicon wafer using a clean track MARK8 manufactured by Tokyo Electron, PB is performed under the conditions shown in Table 1 to form a resist having a film thickness of 500 nm. A film was formed.
Next, while maintaining the temperature at 23 ° C., rinsing with ultrapure water for 90 seconds while rotating the silicon wafer at 2000 rpm, and shaking off the rinse solution at 4000 rpm for 15 seconds, followed by KrF excimer laser stepper NSR2205EX12B manufactured by Nikon Corporation. Using a numerical aperture of 0.55, a 180 nm line and space pattern was exposed, and the exposure amount at which the line width was 180 nm was determined as the optimum exposure amount (sensitivity). PEB was performed under the conditions shown in Table 1. Thereafter, a 2.38 wt% tetramethylammonium hydroxide aqueous solution was used and developed by the paddle method at 23 ° C. for 1 minute, and then washed with pure water and dried to form a resist pattern. The type of the cross-sectional shape of the obtained resist pattern is shown in FIG. In FIG. 1, when the width of the upper side of the pattern shape is a and the width of the lower side is b, when a / b> 1.1, it is “T-top shape defect”, and a / b <0.9. Is “round defect”, and when 0.9 ≦ a / b ≦ 1.1, “pattern shape is good”. In addition, a and b measured the point represented by FIG. 1, and made the average value which measured 10 points | pieces randomly within the wafer as the value of a and b.
resolution:
The minimum dimension that can be resolved at the optimum exposure amount is defined as the resolution.
Depth of focus margin (DOF):
When the focus was changed from −1.0 μm to +1.0 μm at the optimum exposure amount, the range of the line width from 162 nm to 198 nm was defined as the focus depth margin.

  The radiation-sensitive resin composition for immersion exposure according to the present invention is a resist film that is stable to water during immersion exposure because the resist film reduces the affinity for water, there is no variation in film thickness, and a depth of focus margin, Excellent resolution. Therefore, it can be used very suitably for the manufacture of semiconductor devices that are expected to be further miniaturized in the future.

It is a figure showing the cross-sectional shape of a resist pattern.

Explanation of symbols

a Width of the upper side of the pattern shape b Width of the lower side of the pattern shape

Claims (9)

A radiation-sensitive resin composition used for immersion exposure in which radiation is irradiated through water between a lens and a photoresist film, the resin component comprising a resin component and an acid generator, wherein the resin component is a hydroxystyrene unit and A radiation-sensitive polymer comprising a repeating unit containing an acid-dissociable group-containing component, wherein the hydroxystyrene unit is contained in an amount of 5 to 65 mol% based on all repeating units constituting the polymer. Resin composition. The radiation sensitive resin composition according to claim 1, wherein the hydroxystyrene unit is represented by the following formula (1).

(In Formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a monovalent organic group, k and l are each an integer of 1 to 3, and k + 1 = 5) is there.) The radiation-sensitive resin composition according to claim 1, wherein the repeating unit containing the acid-dissociable group-containing component is represented by the following formula (2).

(In Formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ , R ^5, and R ⁶ each represent a saturated hydrocarbon group having 1 to 4 carbon atoms.) The radiation-sensitive resin composition according to claim 1, wherein the repeating unit constituting the resin component is a repeating unit containing a hydroxystyrene unit and an acid-dissociable group-containing component. The radiation-sensitive resin composition according to claim 1, wherein the acid generator contains at least one acid generator selected from a nonionic acid generator and an onium salt compound containing a fluorine atom. The radiation-sensitive resin composition according to claim 5, wherein the nonionic acid generator has a solubility in water at 25 ° C of 1 g / 100 ml H ₂ O or less. The radiation-sensitive resin composition according to claim 6, wherein the nonionic acid generator is at least one compound selected from a sulfonimide compound and a disulfonyldiazomethane compound. The acid generator is an onium salt compound containing the nonionic acid generator and the fluorine atom, and 50 parts by weight of the onium salt containing the fluorine atom with respect to 100 parts by weight of the nonionic acid generator. The radiation-sensitive resin composition according to claim 5, comprising: A radiation-sensitive resin composition used for immersion exposure in which radiation is irradiated between water between a lens and a photoresist film via water, the resin composition including a resin component and an acid generator, wherein the acid generator is 25 ° C. the radiation-sensitive resin composition characterized by the solubility of in water comprises a non-ionic acid generators is 1 g / 100 ml H 2 _O or less.

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