Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
1999-11-08
2002-01-08
Ashton, Rosemary (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S914000
Reexamination Certificate
active
06337171
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a radiation-sensitive resin composition useful for microfabrication using various types of radiation, in particular, such as far ultraviolet rays represented by a KrF excimer laser, charged particle rays such as electron beams, and X-rays such as synchrotron radiation.
2. Description of Background Art
As a resist applicable to far ultraviolet rays such as a KrF excimer laser, charged particle rays such as electron beams, and X-rays such as synchrotron radiation, a chemically-amplified resist comprising a photoacid generator which can increase the sensitivity by the catalytic action of an acid formed by the photoacid generator upon irradiation with radioactive rays (hereinafter called “exposure”) has been proposed.
The following problem has been pointed out for conventional chemically-amplified resists. Specifically, because of the time delay from exposure to heating after exposure (hereinafter referred to as “PED”), the line width of the resist pattern varies or the resist pattern changes into a T-shape. In recent years, various chemically-amplified resists which can be applied to the manufacture of semiconductor devices have been proposed. For example, Japanese Patent Application Laid-open No. 209868/1995 has disclosed a chemically-amplified radiation-sensitive resin composition comprising a polymer which comprises a hydroxystyrene recurring unit, a t-butyl (meth)acrylate recurring unit, and a recurring unit which reduces the solubility of the polymer in an alkaline developer after exposure.
However, as the design dimensions of the devices become more minute such as half micron or less, the chemically amplified resist exhibits defects during development (“defective development”) such as development failure in the minute pattern, fall down of the pattern, and changes in the line width due to unevenness in the solubility of the exposed area in the developer to decrease the yield.
In view of the above situation of the conventional technology, an object of the present invention is to provide a radiation-sensitive resin composition useful as a chemically-amplified resist which exhibits no defective development, and does not cause the line width to change nor the resist pattern to change into a T-shape due to PED. Another object of the present invention is to provide a radiation-sensitive resin composition which exhibits high sensitivity to various radiations such as far ultraviolet rays such as a KrF excimer laser, charged particle rays such as electron beams, and X-rays such as synchrotron radiation and exhibits superior resolution.
SUMMARY OF THE INVENTION
According to the present invention, the above objects can be achieved by a radiation-sensitive resin composition comprising:
(A) a resin which comprises a recurring unit (1) shown by the following formula (1) and either or both of a recurring unit (2) shown by the following formula (2) and a recurring unit (3) shown by the following formula (3):
wherein R
1
represents a hydrogen atom or a methyl group;
wherein R
2
represents a hydrogen atom or a methyl group and R
3
represents a tertiary alkyl group having 4-10 carbon atoms or a 1,1-dimethyl-3-oxobutyl group;
wherein R
4
represents a hydrogen atom or a methyl group and R
5
represents a t-butyl group or acetyl group; and
(B) a photoacid generator shown by the following formula
wherein (a) R
6
-R
11
individually represent a hydrogen atom or a monovalent organic group having 1-6 carbon atoms, provided that at least one of R
6
-R
11
represents a group other than a hydrogen atom; provided further that, (b) two among R
6
-R
8
may form a 3-8 membered cyclic structure together with the carbon atoms of the benzene ring to which these groups are bonded, (c) R
9
-R
11
may form a 3-8 membered cyclic structure together with the carbon atoms in the benzene ring to which these groups are bonded, or (d) two among R
6
-R
8
may form a 3-8 membered cyclic structure together with the carbon atoms of the benzene ring to which these groups are bonded and two among R
9
-R
11
may form a 3-8 membered cyclic structure together with the carbon atoms in the benzene ring to which these groups are bonded.
Other objects, features and advantages of the invention will hereinafter become more readily apparent from the following description.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENT
The present invention will be described in detail.
(A) Resin
The component (A) of the present invention is a resin comprising the recurring unit (1) and either the recurring unit (2) or the recurring unit (3), or both (hereinafter referred to as “resin (A)”).
As the recurring unit (1), units derived from p-hydroxystyrene and the like are particularly preferable.
In the formula (2) which shows the recurring unit (2), examples of a tertiary alkyl group having 4-10 carbon atoms represented by R
3
include a t-butyl group, 1,1-dimethylpropyl group, 1-methyl-1-ethylpropyl group, 1,1-diethylpropyl group, 1,1-dimethylbutyl group, 1-methyl-1-ethylbutyl group, 1,1-diethylbutyl group, 1,1-dimethylpentyl group, 1-methyl-1-ethylpentyl group, 1,1-diethylpentyl group, 1,1-dimethylhexyl group, 1-methyl-1-ethylhexyl group, 1,1-diethylhexyl group, 1,1-dimethylheptyl group, 1-methyl-1-ethylheptyl group, 1,1-dimethyloctyl group, and the like.
A t-butyl group, 1,1-dimethylpropyl group, 1,1-dimethyl-3-oxobutyl group (—C (CH
3
)
2
CH
2
C(═O) CH
3
), and the like are particularly preferable as R
3
.
As the recurring unit (3), units derived from p-t-butoxystyrene, p-acetyloxystyrene, and the like are preferable. P-t-butoxystyrene is particularly preferable.
In the resin (A), various types of groups for the recurring units (1), (2), and (3) mentioned above may be used either individually or in combinations of two or more.
The resin (A) can comprise at least one recurring unit other than the recurring units (1), (2), and (3) (hereinafter referred to as “other recurring units”).
Among monomers which can be used as the other recurring units, examples of monofunctional monomers having one polymerizable unsaturated group in the molecule include vinyl aromatic compounds such as styrene, &agr;-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-methoxystyrene, m-methoxystyrene, and p-methoxystyrene; unsaturated carboxylic acids or acid anhydrides thereof such as (meth)acrylic acid, maleic acid, fumaric acid, crotonic acid, mesaconic acid, citraconic acid, itaconic acid, maleic anhydride, and citraconic anhydride; esters such as methyl ester, ethyl ester, n-propyl ester, i-propyl ester, n-butyl ester, i-butyl ester, sec-butyl ester, t-butyl ester (excluding t-butyl (meth)acrylate), N-amyl ester, n-hexyl ester, cyclohexyl ester, 2-hydroxyethyl ester, 2-hydroxypropyl ester, 3-hydroxypropyl ester, 2,2-dimethyl-3-hydroxypropyl ester, benzyl ester, isobornyl ester, tricyclodecanyl ester, and 1-adamantyl ester of the above unsaturated carboxylic acids; unsaturated nitriles such as (meth)acrylonitrile, maleinitrile, fumarnitrile, mesaconitrile, citraconitrile, and itaconitrile; unsaturated amides such as (meth)acrylamide, crotonamide, maleinamide, fumaramide, mesaconamide, citraconamide, and itaconamide; unsaturated imides such as maleimide, N-phenylmaleimide, and N-cyclohexylmaleimide; unsaturated alcohols such as (meth)allyl alcohol; N-vinylaniline, vinylpyridines, N-vinyl-&egr;-caprolactam, N-vinylpyrrolidone, N-vinylimidazole, N-vinylcarbazole; and the like.
Of these monofunctional monomers, vinyl aromatic compounds and esters of unsaturated carboxylic acids are preferable. Styrene, methyl (meth)acrylate, and the like are particularly preferable.
Among monomers which can be used as the other recurring units, examples of polyfunctional monomers having two or more polymerizable unsaturated groups in the molecule include esters of a compound having two or more hydroxyl groups in the molecule (such as polyhydric alcohols, polyether diol, and polyester diol) and (meth)acrylic acid; addition products of a compound having two or mor
Kobayashi Eiichi
Nishimura Yukio
Shioya Takeo
Ashton Rosemary
JSR Corporation
Kelber Steven B.
Marbury Piper
Rudnick & Wolfe LLP
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