JPH1130865A - Radiation-sensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin compsn. which can be used for various solvents for a resist and which especially shows extremely excellent sensitivity and excellent resolution, pattern profile and scum by incorporating a specified copolymer and a specified radiation-sensitive acid producing agent. SOLUTION: This compsn. contains a copolymer expressed by formula I and one kind of radiation-sensitive acid producing agent expressed by formula II or the like. In formula I, R<1> , R<2> and R<3> are independently hydrogen atoms or methyl groups, R<4> is 1 to 6C alkyl group or phenyl group, R<5> is 1 to 10C alkyl group, 6 to 10C aryl group, etc., Y is 6 to 20C aryl group, etc., a, b, c represent proportions of the respective repeating units satisfying a>0, b>0, c>0 and a+b+c=1. In formula II, R<6> is 1 to 6C alkyl group or phenyl group and three of R<6> may be same or different, R<7> is 1 to 10C alkyl group, 1 to 10C perfluoroalkyl group, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical amplification containing a specific copolymer and a specific radiation-sensitive acid generator and useful for fine processing using various radiations including far ultraviolet rays such as an excimer laser. The present invention relates to a radiation-sensitive resin composition useful as a positive resist.

[0002]

2. Description of the Related Art In the field of microfabrication represented by the manufacture of integrated circuit elements, the processing size in lithography has been reduced in order to obtain a higher degree of integration. There is a need for a technique capable of performing fine processing with good reproducibility. Therefore, even in resists used for microfabrication, 0.5 μm
It is necessary to form a pattern with a size of 0.5 m or less with high precision, but in the conventional method using visible light (wavelength 800 to 400 nm) or near ultraviolet light (wavelength 400 to 300 nm), a fine pattern of 0.5 μm or less can be formed with high precision. Is extremely difficult to form. Therefore, a shorter wavelength (wavelength 3
The use of radiation (less than 00 nm) is being studied earnestly.
Examples of such short-wavelength radiation include X-rays such as far-ultraviolet rays and synchrotron radiation typified by the emission line spectrum of a mercury lamp (wavelength 254 nm), KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), and the like. Examples include charged particle beams such as electron beams and electron beams. Of these, lithography using an excimer laser has attracted attention especially because of its high output and high efficiency characteristics. For this reason, resists used for lithography are required to be able to form fine patterns of 0.5 μm or less with high sensitivity, high resolution, and high reproducibility by excimer laser. As a resist suitable for deep ultraviolet rays such as excimer laser, a radiation-sensitive acid generator that generates an acid by irradiation with radiation (hereinafter referred to as “exposure”) is used, and the sensitivity of the resist is increased by the catalytic action of the acid. An improved “chemically amplified resist” has been proposed. Examples of such a chemically amplified resist include, for example, JP-A-59-45439.
JP-A-60-52845 discloses a combination of a resin protected with a t-butyl group or a t-butoxycarbonyl group and a radiation-sensitive acid generator, and JP-A-60-52845 discloses a combination of a resin protected with a silyl group. Combinations with radiation-sensitive acid generators are each disclosed. In addition, many reports have been made on chemically amplified resists, such as resists containing an acetal group-containing resin and a radiation-sensitive acid generator (Japanese Patent Laid-Open No. 25850/1990). The resins used in these chemically amplified resists have a structure in which some or all of the hydroxyl groups of polyhydroxystyrene have been modified with the above functional groups, and the acid generated from the radiation-sensitive acid generator upon exposure to light. Utilizing a change in the solubility of the resin in an alkaline developer before and after exposure due to a phenomenon in which the functional group is decomposed by the action and a modified hydroxyl group in the resin is regenerated. However, it is often a problem that the solubility of polyhydroxystyrene in an alkali developing solution is too high. For example, there is a disadvantage that resolution is insufficient and pattern shape is deteriorated. Examples of the radiation-sensitive acid generator used in the chemically amplified resist include onium salts such as triphenylsulfonium trifluoromethanesulfonate, sulfonic acid esters of 2,6-dinitrobenzyl, and tris (methanesulfonyloxy). ) Benzene, bis (cyclohexylsulfonyl) diazomethane and the like are used. However,
Various problems have been pointed out with these radiation-sensitive acid generators. For example, onium salts generally have low solubility in resist solvents, so that careful attention is required when preparing the resist, and there is a problem that a great deal of labor is required for quality control. Residue (scum) may occur, and the rectangular shape of the head of the resist pattern is also insufficient, which is not practically satisfactory. In addition, 2,6-dinitrobenzyl sulfonic acid ester, tris (methanesulfonyloxy) benzene and bis (cyclohexylsulfonyl) diazomethane have good solubility in resist solvents but low sensitivity.
It is not suitable as a photosensitive agent for a chemically amplified resist. Incidentally, the sensitivity of the resist is preferably such that the exposure amount required for pattern formation is in the range of 10 to 100 mJ / cm ² ,
More preferably, it is in the range of 15 to 70 mJ / cm ² . If the amount of exposure required for pattern formation is too large, the productivity of the device will decrease. Conversely, if the amount of exposure is too small, it will be difficult to control the amount of exposure and control the line width of the resist pattern. Under these circumstances, the development of radiation-sensitive acid generators that not only can provide excellent resist performance (high resolution, good pattern shape, good sensitivity, etc.) but also have excellent solubility in resist solvents has been strongly developed. Is desired.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to use various resist solvents, and in particular, the sensitivity is extremely excellent.
Another object is to provide a radiation-sensitive resin composition useful as a chemically amplified positive resist excellent in resolution, pattern shape, scum, and the like.

[0004]

According to the present invention, the object is to provide: (A) a copolymer represented by the following formula (1); and (B) a copolymer represented by the following formulas (2), (3) and (3). This is achieved by a radiation-sensitive resin composition containing at least one radiation-sensitive acid generator represented by (4) or (5).

[0005]

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In the formula (1), R ¹ , R ² and R
³ represents a hydrogen atom or a methyl group independently of one another, R ⁴
Represents an alkyl group having 1 to 6 carbon atoms or a phenyl group,
R ⁵ is 6 alkyl or carbon number of 1 to 10 carbon atoms
Y represents an aryl group having 6 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, or R ⁴ and R ⁵ are bonded to each other to form a 5- to 7-membered cyclic structure. OZ group (where Z is an alkyl group having 1 to 10 carbon atoms, 6 to 10 carbon atoms)
Or an aralkyl group having 7 to 10 carbon atoms. ), A, b and c indicate the abundance ratio of each repeating unit, and when a> 0, b> 0, c> 0, a + b + c = 1
It is. ]

[0007]

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[In the formula (2), R ⁶ has 1 to 6 carbon atoms.
And three R ^{6 s} may be the same or different from each other, and R ⁷ is an alkyl group having 1 to 10 carbon atoms, a perfluoroalkyl group having 1 to 10 carbon atoms, and 6 carbon atoms. An aryl group having from 10 to 10; an aralkyl group having from 7 to 10 carbon atoms; or a group having an alicyclic skeleton having from 4 to 12 carbon atoms. )

[0009]

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[In the formula (3), R ⁷ has 1 to 1 carbon atoms.
An alkyl group having 0, a perfluoroalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or a group having an alicyclic skeleton having 4 to 12 carbon atoms, R ⁸ and R ⁹ represents a hydroxyl group or an alkoxyl group having 1 to 6 carbon atoms independently of one another, R ¹⁰ and R
¹¹ independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; d is an integer of 0 to 4; e is an integer of 0 to 3;
Is an integer of 4 to 7, and a plurality of R ⁸ , R ⁹ , R ¹⁰
Alternatively, R ¹¹ may be mutually the same or different. ]

[0011]

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[In the formula (4), R ¹² and R ¹³ each independently represent a monovalent acyclic hydrocarbon group having 1 to 10 carbon atoms;
Cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, a monovalent other organic group having an aralkyl group or a hetero atom having 7 to 20 carbon atoms, X ¹ and X
² is independently a hydrogen atom, a halogen atom, a carbon number of 1
Represents an alkyl group having 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms, g is an integer of 2 to 10, and a plurality of X ¹ and X ² are mutually the same or different. You may. ]

[0013]

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[In the formula (5), R ⁷ has 1 to 1 carbon atoms.
An alkyl group having 0, a perfluoroalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or a group having an alicyclic skeleton having 4 to 12 carbon atoms, R ¹⁴ and R ¹⁵ each independently have 1 to 1 carbon atoms.
6 represents an alkyl group. ]

Hereinafter, the present invention will be described in detail. (A) Component The (A) component in the present invention comprises a copolymer represented by the formula (1) (hereinafter, referred to as “copolymer (A)”). The copolymer (A) may be a random copolymer or a block copolymer. In the formula (1), the carbon number of R ⁴ is 1
The alkyl groups 6 to 6 may be linear, branched or cyclic, and include, for example, methyl, ethyl, n
-Propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, cyclopentyl group, cyclohexyl group and the like. be able to. R ⁴
As the alkyl group and phenyl group of the above, a methyl group, an ethyl group and a cyclohexyl group are preferable.

The alkyl group having 1 to 10 carbon atoms of R ⁵ may be linear, branched or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group and an i-
Propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-pentyl, neopentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-decyl , A cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and the like. The aryl group having 6 to 10 carbon atoms may be unsubstituted or substituted, and examples thereof include a phenyl group, an o-methylphenyl group, m-methylphenyl group, p-methylphenyl group,
p-ethylphenyl group, o-methoxyphenyl group, m-
Methoxyphenyl group, p-methoxyphenyl group, p-ethoxyphenyl group, pn-propoxyphenyl group, p
-N-butoxyphenyl group, pt-butoxyphenyl group, 1-naphthyl group, 2-naphthyl group and the like. As the alkyl group and the aryl group of R ⁵ ,
An ethyl group, a t-butyl group, a cyclohexyl group, and a phenyl group are preferred. Examples of the 5- to 7-membered cyclic structure in which R ⁴ and R ⁵ are bonded include a tetrahydrofuranyl group and a tetrahydropyranyl group.

The aryl group having 6 to 20 carbon atoms of Y may be unsubstituted or substituted, and examples thereof include a phenyl group, an o-methylphenyl group, an m-methylphenyl group and a p-methylphenyl. Group, p-ethylphenyl group, o
-Methoxyphenyl group, m-methoxyphenyl group, p-
Methoxyphenyl group, p-ethoxyphenyl group, pn
-Propoxyphenyl group, pn-butoxyphenyl group, pt-butoxyphenyl group, 1-naphthyl group, 2
-Naphthyl group, 1-anthranyl group, 9-anthranyl group, 9-phenanthryl group and the like. Y
As the aryl group, a phenyl group, a p-ethylphenyl group and a 1-naphthyl group are preferable. In addition, -C of Y (=
O) In the OZ group, the alkyl group having 1 to 10 carbon atoms of Z may be linear, branched or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, and an i-type group.
-Propyl group, n-butyl group, i-butyl group, sec-
Butyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-decyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group, and the like. Yes, Z
May be unsubstituted or substituted, and examples thereof include a phenyl group, an o-methylphenyl group, an m-methylphenyl group, a p-methylphenyl group, and a p-ethylphenyl. Group, o-methoxyphenyl group, m-methoxyphenyl group, p-methoxyphenyl group, p-ethoxyphenyl group, pn-propoxyphenyl group, pn-butoxyphenyl group, pt-butoxyphenyl group, Examples thereof include a 1-naphthyl group and a 2-naphthyl group. The aralkyl group having 7 to 10 carbon atoms in Z may be unsubstituted or substituted, and examples thereof include a benzyl group and a p-methylbenzyl group. A p-ethylbenzyl group, a 1-phenylethyl group, a 1- (p-methylphenyl) ethyl group, a 2-phenylethyl group, a 2- (p-methylphenyl) ethyl group, - phenylpropyl group, 2-
Phenylpropyl group, 2-phenyl-2-propyl group,
Examples include a 3-phenylpropyl group. Examples of the alkyl group, aryl group and aralkyl group of Z include:
A t-butyl group, a cyclohexyl group, a benzyl group, and a 1-phenylethyl group are preferred. In the formula (1), R ⁴ ,
One or more of R ⁵ and Y can each be present.

A in the formula (1) is preferably 0.1 to 0.8, more preferably 0.2 to 0.7, particularly preferably 0.3 to 0.7, and b is Preferably 0.03-0.5, more preferably 0.05-0.
4, particularly preferably 0.1 to 0.3, and c is preferably 0.05 to 0.6, more preferably 0.1 to 0.3.
0.5, particularly preferably 0.1 to 0.4. In this case, if a is less than 0.1, the adhesion of the composition to the substrate tends to decrease, and if it exceeds 0.8, the amount of film loss during development of the composition tends to increase. B is 0.03
If it is less than 0.5, the effect of improving the resolution as a resist tends to decrease. If it exceeds 0.5, the adhesion of the composition to the substrate tends to decrease. If c is less than 0.05, the effect of improving the resolution as a resist and the effect of improving the pattern shape tend to decrease, and if it exceeds 0.6, the sensitivity as a resist tends to decrease.

The copolymer (A) can be produced, for example, by the following methods. at least one of p-hydroxystyrene and p-isopropenylphenol, at least one of styrene and α-methylstyrene, and at least one of 1-alkoxyalkylstyrene and 1-alkoxyalkyl-α-methylstyrene, Copolymerization method. A part of the phenolic hydroxyl group in a copolymer of at least one of p-hydroxystyrene and p-isopropenylphenol and at least one of styrene and α-methylstyrene is converted to, for example, ethyl vinyl ether, vinyl phenyl ether. And an addition reaction with an unsaturated compound such as 2,3-dihydropyran. A part of the phenolic hydroxyl group in a copolymer of at least one of p-hydroxystyrene and p-isopropenylphenol and at least one of styrene and α-methylstyrene is converted to, for example, a compound represented by the formula Cl—CH (R ⁴ )
OR ⁵ method of etherification with (however, R ⁴ and R ⁵ are the same as each ^of R ⁴ and R ⁵ in the formula (1).) A compound represented by. The phenolic hydroxyl group-containing copolymer used in the above method and the above method is, for example, copolymerizing at least one kind of p-hydroxystyrene and p-isopropenylphenol with at least one kind of styrene and α-methylstyrene. P-protected phenolic hydroxyl group with a suitable protecting group
After copolymerizing at least one of hydroxystyrene and p-isopropenylphenol in which a phenolic hydroxyl group is protected with an appropriate protecting group and at least one of styrene and α-methylstyrene, the protecting group is removed to form a hydroxyl group. Can be synthesized by a method of reproducing the same. Gel permeation chromatography of the copolymer (A) (hereinafter referred to as “GP
C ". )), The weight average molecular weight in terms of polystyrene (hereinafter, referred to as “Mw”) is usually 1,000 to 1
00,000, preferably 3,000-40,000,
More preferably, it is 5,000 to 30,000. In this case, if Mw is less than 1,000, the resolution and heat resistance of the resist tend to decrease,
If it exceeds 00, the sensitivity as a resist tends to decrease.

Component (B) The component (B) in the present invention comprises at least one of the compounds represented by the formulas (2), (3), (4) and (5), and is exposed to light. Causing a chemical change,
It is a radiation-sensitive acid generator that generates an acid (hereinafter, referred to as “acid generator (B)”). First, in the acid generator (B) represented by the formula (2) (hereinafter referred to as “acid generator (B1)”), the alkyl group having 1 to ⁶ carbon atoms of R ⁶ is
It may be linear, branched or cyclic, and examples include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, Examples include a t-butyl group, an n-pentyl group, a neopentyl group, an n-hexyl group, a cyclopentyl group, and a cyclohexyl group. As the alkyl group and phenyl group for R ⁶ , a methyl group and an ethyl group are preferable.

The alkyl group having 1 to 10 carbon atoms of R ⁷ may be linear or branched, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group, neopentyl group,
Examples thereof include an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, and an n-decyl group.
The perfluoroalkyl group of 0 may be linear, branched or cyclic, and examples thereof include a trifluoromethyl group, a pentafluoroethyl group, and a perfluoro-n- group.
Propyl, perfluoro-i-propyl, perfluoro-n-butyl, perfluoro-i-butyl, perfluoro-sec-butyl, perfluoro-t-butyl, perfluoro-n-pentyl Perfluoroneopentyl group, perfluoro-n-hexyl group, perfluoro-n-octyl group, perfluoro-2-ethylhexyl group, perfluoro-n-decyl group, perfluorocyclopentyl group, perfluorocyclohexyl group,
Perfluorocyclooctyl group and the like,
The aryl group having 6 to 10 carbon atoms may be unsubstituted or substituted, and examples thereof include a phenyl group, an o-methylphenyl group, an m-methylphenyl group, a p-methylphenyl group, and a p-ethylphenyl group. , O-methoxyphenyl group,
m-methoxyphenyl group, p-methoxyphenyl group, p
-Ethoxyphenyl group, pn-propoxyphenyl group, pn-butoxyphenyl group, pt-butoxyphenyl group, 1-naphthyl group, 2-naphthyl group and the like, and having 7 to 10 carbon atoms. May be unsubstituted or substituted, and examples thereof include a benzyl group, a p-methylbenzyl group, a p-ethylbenzyl group,
-Phenylethyl group, 1- (p-methylphenyl) ethyl group, 2-phenylethyl group, 2- (p-methylphenyl) ethyl group, 1-phenylpropyl group, 2-phenylpropyl group, 2-phenyl-2 -Propyl group, 3-phenylpropyl group and the like, having 4 to 12 carbon atoms.
Examples of the group having an alicyclic skeleton include a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a norbornyl group, a camphanyl group, and the like. Examples of the alkyl group, perfluoroalkyl group, aryl group, aralkyl group, and group having an alicyclic skeleton having 4 to 12 carbon atoms of R ⁷ include an n-butyl group, an n-hexyl group, an n-octyl group, and a cyclohexyl group. , A trifluoromethyl group, a pentafluoroethyl group, a perfluoro-n-propyl group, a perfluoro-n-butyl group, a phenyl group, a p-methylphenyl group, and a camphanyl group.

Next, the acid generator (B) represented by the formula (3)
(Hereinafter referred to as “acid generator (B2)”).
⁷ alkyl groups having 1 to 10 carbon atoms, perfluoroalkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 10 carbon atoms,
Examples of the group having an aralkyl group having 7 to 10 carbon atoms and an alicyclic skeleton having 4 to 12 carbon atoms include the same groups as those exemplified for R ^{7 in the} acid generator (1). . R ⁷ alkyl group, perfluoroalkyl group, aryl group, aralkyl group and C 4-12
Groups having an alicyclic skeleton of n-butyl group, n-
Hexyl group, n-octyl group, cyclohexyl group, trifluoromethyl group, pentafluoroethyl group, perfluoro-n-propyl group, perfluoro-n-butyl group,
A phenyl group, a p-methylphenyl group and a camphanyl group are preferred. Further, the alkoxyl group having 1 to 6 carbon atoms of R ⁸ and R ⁹ can be linear, branched or cyclic, and examples thereof include a methoxy group, an ethoxy group and an n-
Propoxy group, i-propoxy group, n-butoxy group, i
-Butoxy group, sec-butoxy group, t-butoxy group,
Examples thereof include an n-pentyloxy group, an n-hexyloxy group, a cyclopentyloxy group, and a cyclohexyloxy group. The hydroxyl group and the alkoxyl group of R ⁸ and R ⁹ include a hydroxyl group, a methoxy group, an ethoxy group, and n
-A propoxy group, an n-butoxy group and a t-butoxy group are preferred. Examples of the alkyl group having 1 to 4 carbon atoms for R ¹⁰ and R ¹¹ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and a sec-butyl group. And a t-butyl group. As the hydrogen atom and the alkyl group for R ¹⁰ and R ¹¹ , a hydrogen atom, a methyl group, and an ethyl group are preferable.

Next, the acid generator (B) represented by the formula (4)
(Hereinafter referred to as “acid generator (B3)”).
The monovalent acyclic hydrocarbon radical having 1 to 10 carbon atoms ¹² and R ^13, for example, an alkyl group, an alkenyl group, and alkadienyl group. The carbon number 1
Among the 10 monovalent acyclic hydrocarbon groups, examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group,
Isopropyl group, n-butyl group, sec-butyl group, t
-Butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group and the like.Examples of the alkenyl group include CH ₂ = CH-, CH ₂ = CHCH _2- , CH ₂ = C (CH
₃ )-, CH ₂ = CHCH ₂ CH _2- , CH ₂ = C (CH ₃ ) CH _2- , CH ₃ CH = CHCH
_2- , CH ₂ = CH ₂ CH ₂ CH ₂ CH _2- , CH ₂ = C (CH ₃ ) CH ₂ CH _2- , CH ₂ = CH
₂ CH ₂ CH ₂ CH ₂ CH _2- and the like.Examples of the alkadienyl group include, for example, CH ₂ = CHCH = CH-, CH ₂ = CHCH = CHCH _{2-.
, CH 2 = C (CH 3} ) CH = CH-, CH 2 = CHCH 2 CH = CH-, CH 2 = CHCH = CH
CH ₂ CH _2- and the like can be mentioned. Also, R ¹² and R
Examples of the ¹³ cycloalkyl group having 3 to 10 carbon atoms include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Further, R ¹² and R ¹³ have 6 to 20 carbon atoms.
May be unsubstituted or substituted, and examples thereof include a phenyl group, a p-methylphenyl group and a p-methylphenyl group.
Examples thereof include a t-butylphenyl group, a biphenylyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a 9-anthryl group, and a 9-phenanthryl group.
Further, the aralkyl group having 7 to 20 carbon atoms of R ¹² and R ¹³ may be unsubstituted or substituted, and examples thereof include:
Benzyl group, p-methylbenzyl group, p-ethylbenzyl group, diphenylmethyl group, 3,5-diphenylbenzyl group, 1-phenylethyl group, 1- (p-methylphenyl) ethyl group, 2-phenylethyl group, 2- (p-methylphenyl) ethyl group, 1-phenylpropyl group, 2-
Phenylpropyl group, 2-phenyl-2-propyl group,
3-phenylpropyl group, 1-naphthylmethyl group, 2-
Examples include a naphthylmethyl group, a 1-anthranylmethyl group, and a 9-anthranylmethyl group. Also, R
1 to 10 carbon atoms having a heteroatom of ¹² and R ¹³
Examples of other organic groups having a valence include a camphanyl group, a cyano group, a dimethylaminocarbonyl group, a 4-bromobenzoyl group, a 2-pyridinyl group, and a 4-pyridinyl group. Examples of the monovalent acyclic hydrocarbon group, cycloalkyl group, aryl group, aralkyl group and other monovalent organic groups represented by R ¹² and R ¹³ include a methyl group, an ethyl group, a t-butyl group, a cyclohexyl group, Phenyl group, p
-Methylphenyl group, pt-butylphenyl group, 1-
A naphthyl group and a benzyl group are preferred.

Examples of the halogen atom for X ¹ and X ² include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. X ¹ and X ²
The alkyl group having 1 to 10 carbon atoms may be linear, branched or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, i-butyl group, sec-butyl group, t-butyl group,
n-pentyl group, neopentyl group, n-hexyl group, n
-Octyl group, 2-ethylhexyl group, n-decyl group,
Examples thereof include a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. The aryl group having 6 to 10 carbon atoms may be unsubstituted or substituted.
Phenyl group, o-methylphenyl group, m-methylphenyl group, p-methylphenyl group, p-ethylphenyl group,
o-methoxyphenyl group, m-methoxyphenyl group, p
-Methoxyphenyl group, p-ethoxyphenyl group, p-
n-propoxyphenyl group, pn-butoxyphenyl group, pt-butoxyphenyl group, 1-naphthyl group, 2
And an aralkyl group having 7 to 10 carbon atoms may be unsubstituted or substituted. Examples thereof include a benzyl group, a p-methylbenzyl group, and a p-methyl aralkyl group.
Ethylbenzyl group, 1-phenylethyl group, 1- (p-
Methylphenyl) ethyl group, 2-phenylethyl group, 2
-(P-methylphenyl) ethyl group, 1-phenylpropyl group, 2-phenylpropyl group, 2-phenyl-2-
Examples thereof include a propyl group and a 3-phenylpropyl group. Examples of the hydrogen atom, halogen atom, alkyl group, aryl group and aralkyl group of X ¹ and X ² include a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, an ethyl group,
A phenyl group and a benzyl group are preferred. In addition, g in the acid generator (B3) is preferably an integer of 3 to 6.

Next, the acid generator (B) represented by the formula (5)
(Hereinafter referred to as “acid generator (B4)”).
⁷ alkyl groups having 1 to 10 carbon atoms, perfluoroalkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 10 carbon atoms,
Examples of the group having an aralkyl group having 7 to 10 carbon atoms and an alicyclic skeleton having 4 to 12 carbon atoms include the same groups as those exemplified for R ^{7 in the} acid generator (1). . R ⁷ alkyl group, perfluoroalkyl group, aryl group, aralkyl group and C 4-12
Groups having an alicyclic skeleton of n-butyl group, n-
Hexyl group, n-octyl group, cyclohexyl group, trifluoromethyl group, pentafluoroethyl group, perfluoro-n-propyl group, perfluoro-n-butyl group,
A phenyl group, a p-methylphenyl group and a camphanyl group are preferred. Further, the alkyl group having 1 to 6 carbon atoms of R ¹⁴ and R ¹⁵ can be linear, branched or cyclic,
Examples include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s
Examples include an ec-butyl group, a t-butyl group, an n-pentyl group, a neopentyl group, an n-hexyl group, a cyclopentyl group, a cyclohexyl group, and the like. R ¹⁴ and R ¹⁵
As the alkyl group having 1 to 10 carbon atoms, a methyl group, an ethyl group, and a t-butyl group are preferable.

The amount of the acid generator (B) used in the present invention is usually 0.1 parts per 100 parts by weight of the copolymer (A).
-30 parts by weight, preferably 0.5-20 parts by weight, more preferably 1-15 parts by weight. In this case, if the amount of the acid generator (B) used is less than 0.1 part by weight, the sensitivity tends to decrease, and if it exceeds 30 parts by weight, the pattern shape tends to deteriorate.

Acid Diffusion Control Agent In the present invention, the action of controlling the diffusion phenomenon of the acid generated from the acid generator (B) by exposure in the resist film, and suppressing the undesired chemical reaction in the unexposed area, etc. It is preferable to add an acid diffusion controller having the same. By using such an acid diffusion controlling agent, the resolution as a resist can be further improved, and a temporal change of a resist pattern can be suppressed, so that a composition having extremely excellent process stability can be obtained. The acid diffusion controller is not particularly limited as long as it has the above-mentioned action, but is preferably a nitrogen-containing organic compound whose basicity does not change by exposure or baking. As such a nitrogen-containing organic compound, for example, the following formula (6) R ¹⁶ R ¹⁷ R ¹⁸ N... (6) [In the formula (6), R ¹⁶ , R ¹⁷ and R ¹⁸ are mutually independent. Represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group. (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)"), and a nitrogen atom Having three or more (hereinafter, referred to as
It is called "nitrogen-containing compound (III)". ), Amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds and the like.

Examples of the nitrogen-containing compound (I) include, for example, n
Monoalkylamines such as hexylamine, n-heptylamine, n-octylamine, n-nonylamine and n-decylamine; di-n-butylamine, di-n-pentylamine, di-n-hexylamine, di- dialkylamines such as n-heptylamine, di-n-octylamine, di-n-nonylamine and di-n-decylamine; tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-pentylamine Trialkylamines such as -n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine; aniline, N-methylaniline, N, N-dimethyl Aniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-
Aromatic amines such as nitroaniline, diphenylamine, triphenylamine and naphthylamine can be mentioned. Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane,
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,
Examples thereof include 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene and 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene. Examples of the nitrogen-containing compound (III) include a polymer 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,
Examples thereof include 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, and tributylthiourea. Examples of the nitrogen-containing heterocyclic compound include imidazoles such as imidazole, benzimidazole, 4-methylimidazole and 4-methyl-2-phenylimidazole; pyridine, 2-methylpyridine, 4-methylpyridine and 2-ethylpyridine , 4-ethylpyridine, 2-phenylpyridine, 4-
In addition to pyridines such as phenylpyridine, N-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 8-oxyquinoline, and acridine, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, Morpholine, 4
-Methylmorpholine, piperazine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, and the like. Among these nitrogen-containing organic compounds, a nitrogen-containing compound (I), a nitrogen-containing heterocyclic compound and the like are preferable. Further, among the nitrogen-containing compounds (I), trialkylamines are particularly preferable, and among the nitrogen-containing heterocyclic compounds, pyridines are particularly preferable.

In the present invention, the acid diffusion controlling agents can be used alone or in combination of two or more. The amount of the acid diffusion controller to be used is generally 5 parts by weight or less, preferably 0.001 to 3 parts by weight, more preferably 0.005 to 2 parts by weight, per 100 parts by weight of the copolymer (A).
In this case, if the amount of the acid diffusion controller exceeds 5 parts by weight, the sensitivity and developability as a resist tend to decrease. If the amount of the acid diffusion controller is less than 0.001, the effect of improving the resolution and process stability as a resist may be insufficient.

[0030] In the alkali-soluble resin present invention, it can be optionally added an alkali-soluble resin other than the copolymer (A). The alkali-soluble resin is a resin that is soluble in an alkali developing solution and has at least one functional group having an affinity for an aqueous alkali solution, such as a phenolic hydroxyl group or a carboxyl group. By using such an alkali-soluble resin, it becomes easy to control the dissolution rate of a resist coating formed from the radiation-sensitive resin composition of the present invention in an alkali developer, thereby further improving developability. Can be. The alkali-soluble resin is not particularly limited as long as it is soluble in an alkali developer, but preferred alkali-soluble resins include, for example, hydroxystyrenes, isopropenylphenols, vinylbenzoic acids, carboxymethylstyrenes, Polymerizable double bonds of monomers having acidic functional groups such as carboxymethoxystyrenes, (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and cinnamic acid are cleaved. And the like. Addition polymerization resins containing at least one repeating unit described above can be mentioned. The alkali-soluble resin composed of the addition polymerization resin may be composed of only a repeating unit in which the polymerizable double bond of the monomer having the acidic functional group is cleaved, but the produced resin is alkali-soluble. Insofar as it is, one or more other repeating units may be contained. Such other repeating units include, for example, styrene, α-methylstyrene, vinyl toluene, maleic anhydride, (meth) acrylonitrile, crotonitrile, maleinitrile, fumaronitrile, mesaconitrile, citraconitrile, itaconitrile, ( Polymerizable double bonds of monomers such as (meth) acrylamide, crotonamide, maleamide, fumaramide, mesaconamide, citraconamide, itaconamide, vinylaniline, vinylpyridine, vinyl-ε-caprolactam, vinylpyrrolidone, and vinylimidazole are cleaved. And the repeating unit described above. Among the addition-polymer resins, poly (hydroxystyrene) s and isopropenylphenol copolymers are particularly preferable from the viewpoint of high radiation permeability when formed into a resist film and excellent dry etching resistance. These alkali-soluble resins can be used alone or in combination of two or more. Mw of the alkali-soluble resin is usually 1,000 to 150,
000, preferably 3,000 to 100,000. The amount of the alkali-soluble resin used is the copolymer (A) 1
It is usually 200 parts by weight or less per 100 parts by weight.

Various Additives In the present invention, various additives such as a surfactant and a sensitizer can be added, if necessary. The surfactant, the coating properties and striation of the composition,
It has the effect of improving the developability of the resist. Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol dilaurate, and polyethylene glycol dilaurate. In addition to stearate, the following brand names are used as F Top EF301, EF
303, EF352 (manufactured by Tochem Products), Megafac F171, F173 (manufactured by Dainippon Ink and Chemicals, Inc.), Florado FC430, FC431 (manufactured by Sumitomo 3M Limited), Asahi Guard AG710, Surflon S-382 SC-101, SC-102, SC
-103, SC-104, SC-105, SC-106
(Made by Asahi Glass Co., Ltd.), KP341 (Shin-Etsu Chemical Co., Ltd.)
Manufactured by Polyflow No. 75, no. 95 (manufactured by Kyoeisha Yushi Kagaku Kogyo KK) and the like. These surfactants can be used alone or in combination of two or more. The amount of the surfactant used is usually 2 parts by weight or less per 100 parts by weight of the copolymer (A). Further, the sensitizer absorbs radiation energy and transmits the energy to the acid generator (B), thereby increasing the amount of acid generated by exposure, and has an apparent sensitivity as a resist. Has the effect of improving Preferred sensitizers include, for example, benzophenones, rose bengals, anthracenes and the like. These sensitizers can be used alone or in combination of two or more. The amount of the sensitizer to be added is usually 30 parts by weight or less per 100 parts by weight of the copolymer (A). Further, the radiation-sensitive resin composition of the present invention,
By blending a dye and / or a pigment, the latent image in the exposed area can be visualized to reduce the effect of halation at the time of exposure, and further improving the adhesiveness to the substrate by blending an adhesion aid. Can be. Further, 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 added.

Solvent The radiation-sensitive resin composition of the present invention comprises
The composition is dissolved uniformly in a solvent so that the concentration of the total solid content is, for example, 3 to 50% by weight, preferably 10 to 40% by weight, and then filtered through a filter having a pore size of about 0.2 μm. Prepared as a solution. As the solvent used for preparing the composition solution, for example, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate,
Ethylene glycol monoalkyl ether acetates, such as ethylene glycol mono-n-butyl ether acetate; propylene glycol mono, such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, and propylene glycol mono-n-butyl ether Alkyl ethers; propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether,
Propylene glycol dialkyl ethers such as propylene glycol di-n-butyl ether; propylene such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, and propylene glycol mono-n-butyl ether acetate; Glycol monoalkyl ether acetates; lactate esters such as methyl lactate, ethyl lactate, n-propyl lactate and i-propyl lactate; n-amyl formate;
I-amyl formate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-amyl acetate, i-amyl acetate, n-propyl propionate, i-propyl propionate Carboxylic acid esters such as n-butyl propionate and i-butyl propionate; ethyl hydroxyacetate, 2-hydroxy-2-
Ethyl methyl propionate, 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-methoxybutyl propionate,
Other esters such as 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate and ethyl pyruvate; aromatic hydrocarbons such as toluene and xylene; methyl ethyl ketone and methyl n
Ketones such as -propyl ketone, methyl n-butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone and cyclohexanone; N-methylformamide, N, N
-Dimethylformamide, N-methylacetamide,
Amides such as N, N-dimethylacetamide and N-methylpyrrolidone; lactones such as γ-butyrolactone; These solvents can be used alone or
A mixture of more than one species is used.

Method for Forming Resist Pattern When forming a resist pattern from the radiation-sensitive resin composition of the present invention, the composition solution prepared as described above is spin-coated, cast-coated, roll-coated, etc. For example, a resist film is formed by applying the composition onto a substrate such as a silicon wafer or a wafer coated with aluminum by a suitable application means, and a heat treatment (hereinafter, referred to as “pre-bake”) is performed in advance in some cases. Thereafter, exposure is performed through a predetermined mask pattern. Depending on the type of the acid generator (B), for example, ultraviolet rays such as i-ray (wavelength 365 nm), ArF excimer laser (wavelength 193 nm), KrF excimer laser (wavelength 248 nm), etc. X-rays such as far ultraviolet rays and synchrotron radiation, and charged particle beams such as electron beams are appropriately selected and used, and a KrF excimer laser is particularly preferable. Exposure conditions such as the amount of exposure are appropriately selected according to the composition of the composition, the type of each additive, and the like. In the present invention, in order to improve the apparent sensitivity of the resist film, it is preferable to perform heat treatment after exposure (hereinafter, referred to as “post-exposure bake”). The heating conditions vary depending on the composition of the composition, the type of each additive and the like, but are usually 30 to 200 ° C, preferably 40 to 150 ° C.
It is. Next, a predetermined resist pattern is formed by developing the exposed resist film with an alkaline developer. The processing conditions for this alkali development are usually 10
30 to 200 seconds at ５０50 ° C. Examples of the alkali developer include alkali metal hydroxides; aqueous ammonia; mono-, di- or tri-alkylamines; mono-, di- or tri-alkanolamines; heterocyclic amines; Ammonium hydroxides, choline, 1,8-diazabicyclo- [5,4,
0] -7-undecene, 1,5-diazabicyclo-
Usually, at least one kind of alkaline compound such as [4,3,0] -5-nonene is used in an amount of 1 to 10% by weight, preferably 1 to 10% by weight.
An alkaline aqueous solution dissolved to a concentration of about 5% by weight is used. In addition, an appropriate amount of a water-soluble organic solvent such as methanol or ethanol or a surfactant can be added to the developer composed of the alkaline aqueous solution. When a developer composed of an alkaline aqueous solution is used, washing is generally performed after development. When forming the resist pattern, a protective film may be provided on the resist film in order to prevent the influence of basic impurities and the like contained in the environmental atmosphere.

[0034]

Embodiments of the present invention will be described below more specifically with reference to examples. However, the present invention is not limited to these embodiments. Here, the measurement of the polystyrene-equivalent weight average molecular weight (hereinafter, referred to as “Mn”) by Mw and GPC and the evaluation of each resist were carried out in the following manner. Mw and Mn GPC columns manufactured by Tosoh Corporation (2 G2000H _XL , G
The measurement was performed by GPC using monodisperse polystyrene as a standard under the analysis conditions of 1.0 mL / min flow rate, elution solvent tetrahydrofuran, and column temperature of 40 ° C. using one 3000H _{XL and} one G4000H _XL ). When a sensitivity resist pattern was formed, an exposure amount for forming a line-and-space pattern (1L1S) having a line width of 0.26 μm in a one-to-one line width was defined as an optimum exposure amount, and the sensitivity was evaluated based on the optimum exposure amount. . Resolution The minimum dimension (μm) of the line-and-space pattern (1L1S) resolved when exposure was performed at the optimum exposure amount was defined as the resolution. In a line-and-space pattern (1L1S) having a pattern shape line width of 0.26 μm, the cross section of the pattern is scanned with a scanning electron microscope
Using a mirror , measure the line width at the top of the cross section of the pattern as La,
Assuming that the lower line width is Lb, 0.9 <La / Lb <
In the case of 1.1, the pattern shape was determined to be “good” and 0.9.
In the case of ≧ La / Lb, the pattern shape was evaluated as “round top”, and in the case of La / Lb ≧ 1.1, the pattern shape was evaluated as “T-type”.

[0035]

【Example】

Synthesis Example 1 (1) After dissolving 1408 g (8 mol) of pt-butoxystyrene and 208 g (2 mol) of styrene in 2000 g of propylene glycol monomethyl ether, 20 g of azobisisobutyronitrile was added, and 75 g of azobisisobutyronitrile was added.
Polymerization was carried out at 8 ° C. for 8 hours. Next, the reaction solution was diluted with 7000 g of propylene glycol monomethyl ether, and 500 g of a 10% by weight aqueous sulfuric acid solution was added.
The reaction was carried out for a time to convert the t-butoxy group in the polymer to a hydroxyl group. Next, the reaction solution was added to a large amount of vigorously stirred water, and the produced powdery copolymer was filtered, washed with water, and dried in a vacuum dryer at 50 ° C. overnight. When the obtained copolymer was measured by GPC, Mw = 1
6,000, Mw / Mn = 1.53. When ¹³ C-NMR of this copolymer was measured, it was found that the copolymer was p-hydroxystyrene: styrene = 80: 20 (molar ratio). This copolymer is referred to as a copolymer (α). (2) After dissolving 117 g of the copolymer (α) in 480 g of dry propylene glycol monomethyl ether acetate, pyridinium p-toluenesulfonate.
8 g was added and stirred. Next, while keeping this solution at room temperature, 17.3 g of ethyl vinyl ether was added dropwise,
After stirring for an hour, the reaction solution was dropped into 5 liters of a 0.1% by weight aqueous ammonia solution with vigorous stirring. Next, the resulting powdery copolymer was filtered, washed with water, and dried overnight in a vacuum dryer at 30 ° C. When the obtained copolymer was measured by GPC, Mw = 18,5
00, Mw / Mn = 1.51. When ¹³ C-NMR of this copolymer was measured, the copolymer (α) was obtained.
26% of the phenolic hydroxyl groups therein were chemically modified with 1-ethoxyethyl groups. This copolymer is referred to as a copolymer (A-i).

Synthesis Example 2 117 g of the copolymer (α) obtained in (1) of Synthesis Example 1 was dissolved in 480 g of dry propylene glycol monomethyl ether acetate, and 1.8 g of pyridinium p-toluenesulfonate was added. Stirred. Then, while keeping this solution at room temperature, 2,3-dihydropyran.
5 g was added dropwise, and the mixture was stirred for 8 hours.
The mixture was added dropwise to 5 liters of a 5% by weight aqueous ammonia solution with vigorous stirring. Next, the resulting powdery copolymer was filtered, washed with water, and dried overnight in a vacuum dryer at 30 ° C. When the obtained copolymer was measured by GPC,
Mw = 19,000 and Mw / Mn = 1.55.
When ¹³ C-NMR of this copolymer was measured,
25% of phenolic hydroxyl acid groups in the copolymer (alpha) 2-
It was chemically modified with a tetrahydropyranyl group. This copolymer is referred to as a copolymer (A-B).

Synthesis Example 3 (1) 1297.5 g (8 mol) of p-acetoxystyrene and 324.4 g (2 mol) of benzyl acrylate were mixed with propylene glycol monomethyl ether 20
Azobisisobutyronitrile 2
0 g was added and polymerization was carried out at 75 ° C. for 8 hours. Next, the reaction solution was treated with propylene glycol monomethyl ether 700
After dilution with 0 g, 500 g of a 10% by weight aqueous solution of triethylamine was added and reacted at 90 ° C. for 5 hours to convert an acetoxy group in the copolymer into a hydroxyl group. Next, the reaction solution was added to a large amount of vigorously stirred water, and the produced powdery copolymer was filtered, washed with water, and dried in a vacuum dryer at 50 ° C. overnight. When the obtained copolymer was measured by GPC, Mw = 21,000, Mw / Mn =
It was 1.45. In addition, ¹³ C-NMR of this copolymer
Was a copolymer of p-hydroxystyrene: benzyl acrylate = 79: 21 (molar ratio). This copolymer is referred to as a copolymer (β). (2) After dissolving 129 g of the copolymer (β) in 480 g of dry propylene glycol monomethyl ether acetate, pyridinium p-toluenesulfonate was dissolved in 1.48 g of pyridinium p-toluenesulfonic acid.
8 g was added and stirred. Next, while keeping this solution at room temperature, 17.3 g of ethyl vinyl ether was added dropwise,
After stirring for an hour, the reaction solution was dropped into 5 liters of a 0.1% by weight aqueous ammonia solution with vigorous stirring. Next, the resulting powdery copolymer was filtered, washed with water, and dried overnight in a vacuum dryer at 30 ° C. When the obtained copolymer was measured by GPC, Mw = 23.5
00, Mw / Mn = 1.47. When ¹³ C-NMR of this copolymer was measured, it was found that the copolymer (β)
22% of the phenolic hydroxyl groups therein were chemically modified with 1-ethoxyethyl groups. This copolymer is referred to as a copolymer (A-C).

Comparative Synthesis Example 1 (1) 176 g (1 mol) of pt-butoxystyrene
To 200 g of propylene glycol monomethyl ether
And 2 g of azobisisobutyronitrile was added, followed by polymerization at 75 ° C. for 8 hours. Next, the reaction solution was diluted with 700 g of propylene glycol monomethyl ether, and 50 g of a 10% by weight aqueous sulfuric acid solution was added.
For 5 hours to convert the t-butoxy group in the polymer into a hydroxyl group. Then, the reaction solution was added to a large amount of vigorously stirred water, and the resulting powdery polymer was filtered, washed with water, and then dried in a vacuum dryer at 50 ° C. overnight. When the obtained polymer was measured by GPC, Mw = 1
4,000, Mw / Mn = 1.48. When ¹³ C-NMR of this polymer was measured, poly (p-
Hydroxystyrene). This polymer is referred to as a polymer (γ). (2) After dissolving 120 g of the polymer (γ) in 480 g of dry propylene glycol monomethyl ether acetate, pyridinium p-toluenesulfonate 2.2
g was added and stirred. Next, while maintaining this solution at room temperature, 21.6 g of ethyl vinyl ether was added dropwise, and the mixture was stirred for 8 hours. Then, the reaction solution was added dropwise to 5 liters of a 0.1% by weight aqueous ammonia solution with vigorous stirring. Then, the resulting powdery polymer is filtered, washed with water,
Dry overnight in a vacuum oven at 30 ° C. When the obtained polymer was measured by GPC, Mw = 16,600,
Mw / Mn = 1.50. In addition, ^{13 of} this polymer
When the C-NMR was measured, 28% of the phenolic hydroxyl groups in the polymer (γ) were chemically modified with 1-ethoxyethyl groups. This polymer is referred to as a polymer (a).

Example 1 The copolymer (A-i) obtained in Synthesis Example 1, tris (p-methoxyphenyl) sulfonium trifluoromethanesulfonate as an acid generator (B), and tris as an acid diffusion controller Using -n-octylamine and mixing at a ratio shown in Table 1 (where parts are based on weight) to obtain a uniform solution, the mixture is filtered through a membrane filter having a pore size of 0.2 μm to prepare a composition solution. did. Next, after spin-coating this composition solution onto a silicone wafer,
Was performed for 90 seconds to form a resist film having a thickness of 0.7 μm. Then, on this resist coating,
After exposure using a Nikon KrF excimer laser stepper (trade name: NSR-2005EX8A), 1
A post-exposure bake was performed at 10 ° C. for 90 seconds. Then, 2.
After performing paddle development at 23 ° C. for 1 minute using a 38% by weight aqueous solution of tetramethylammonium hydroxide, the resultant was washed with pure water and dried to form a resist pattern, which was evaluated. Table 2 shows the evaluation results.

Examples 2 to 7 Preparation of a composition solution, formation of a resist pattern, and evaluation were performed in the same manner as in Example 1 except that the components shown in Table 1 were used. Table 2 shows the evaluation results.

Comparative Examples 1-3 Preparation of a composition solution, formation of a resist pattern, and evaluation were performed in the same manner as in Example 1 except that the components shown in Table 1 were used. Table 2 shows the evaluation results. The acid generators shown in Table 1 and (B) other acid generators, acid diffusion controllers and solvents are as follows. Acid generator (B)

B-A:

Embedded image

B-B:

Embedded image

B-C:

Embedded image

B-d:

Embedded image

Other acid generators

B-a:

Embedded image

B-b:

Embedded image

Acid diffusion controller C-1: tri-n-octylamine C-2: 4-phenylpyridine solvent PGMEA: propylene glycol monomethyl ether acetate EL: ethyl lactate EEP: ethyl 1-ethoxy-2-propionate MAK: Methyl n-amyl ketone

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

The radiation-sensitive resin composition of the present invention can use various resist solvents by using a specific resin and a specific radiation-sensitive acid generator, and is particularly excellent in sensitivity and resolution. Also excellent in pattern shape, scum, etc. Moreover, the radiation-sensitive resin composition of the present invention can effectively respond to various radiations such as ultraviolet rays, far ultraviolet rays, X-rays, and charged particle beams. Therefore, the radiation-sensitive resin composition of the present invention is extremely useful as a chemically amplified positive resist for manufacturing semiconductor devices, which is expected to be further miniaturized in the future.

Continuation of the front page (72) Inventor Shinichiro Iwanaga 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside Nippon Gosei Rubber Co., Ltd.

Claims (1)

[Claims] (1) A copolymer represented by the following formula (1) and (B) a copolymer represented by the following formula (2), (3), (4) or (5): A radiation-sensitive resin composition comprising at least one radiation-sensitive acid generator. Embedded image [In the formula (1), R ¹ , R ² and R ³ independently represent a hydrogen atom or a methyl group, and R ⁴ has 1 to 1 carbon atoms.
And R ⁵ represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms, or a 5- to 7-membered ring wherein R ⁴ and R ⁵ are bonded to each other. Wherein Y is an aryl group having 6 to 20 carbon atoms or a —C (＝ O) OZ group (where Z is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms) Or an aralkyl group having 7 to 10 carbon atoms).
a, b and c indicate the abundance ratio of each repeating unit, and a>
0, b> 0, c> 0, and a + b + c = 1. [Chemical formula 2] [In the formula (2), R ⁶ represents an alkyl group having 1 to ⁶ carbon atoms or a phenyl group, and three R ⁶ may be the same or different from each other, and R ⁷ is an alkyl group having 1 to 10 carbon atoms. ,
C1-C10 perfluoroalkyl group, C6-C
It represents a 10-aryl group, an aralkyl group having 7 to 10 carbon atoms, or a group having an alicyclic skeleton having 4 to 12 carbon atoms. ) [In the formula (3), R ⁷ is an alkyl group having 1 to 10 carbon atoms, a perfluoroalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or a carbon number. A group having 4 to 12 alicyclic skeletons,
R ⁸ and R ⁹ are each independently a hydroxyl group or a C 1 -C 1
6 represents an alkoxyl group; R ¹⁰ and R ¹¹ independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms;
d is an integer of 0 to 4, e is an integer of 0 to 3, f is an integer of 4 to 7, and a plurality of R ⁸ , R ⁹ , R ¹⁰ or R ¹¹
May be the same or different from each other. [Formula 4] [In the formula (4), R ¹² and R ¹³ are each independently a monovalent acyclic hydrocarbon group having 1 to 10 carbon atoms, and 3 to 1 carbon atoms.
A cycloalkyl group of 0, an aryl group having 6 to 20 carbon atoms,
X represents an aralkyl group having 7 to 20 carbon atoms or another monovalent other organic group having 1 to 10 carbon atoms having a hetero atom, and X ¹ and X ² each independently represent a hydrogen atom, a halogen atom, Represents an alkyl group, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms, and g is 2 to 1
It is an integer of 0, and a plurality of X ¹ and X ² may be mutually the same or different. [Chemical formula 5] [In the formula (5), R ⁷ is an alkyl group having 1 to 10 carbon atoms, a perfluoroalkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or a carbon number. A group having 4 to 12 alicyclic skeletons,
R ¹⁴ and R ¹⁵ each independently represent an alkyl group having 1 to 6 carbon atoms. ]