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
2000-12-20
2001-11-27
Ashton, Rosemary E. (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
C430S921000, C430S927000
Reexamination Certificate
active
06322949
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to a positive-tone or negative-tone radiation sensitive resin composition which contains a specific photoacid generator and is useful as a resist suitable for use in precision machining utilizing various types of radiation such as ultraviolet light, deep ultraviolet light, X-rays, or charged particle rays.
2. Description of the Background Art
There is an increasing demand for miniaturization, requiring reduced processing sizes in lithography, in fields requiring fine work such as manufacture of integrated circuits (ICs) in order to achieve high integrity in ICs. Technologies capable of fine processing, even of a size of 0.5 mm or smaller, in a stable manner have become necessary in recent years. Because of this, resists used in such a technology must be capable of forming patterns smaller than 0.5 mm at high precision. It is extremely difficult to produce a minute pattern smaller than 0.5 mm at a high precision by conventional methods using visible light (wavelength 800-400 nm) or near ultraviolet light (wavelength 400-300 nm). Because of this, the use of short wavelength radiation (wavelength 300 nm or less) has been studied.
Given as examples of such a short wavelength radiation are deep ultraviolet rays, such as a bright line spectrum of a mercury lamp (wavelength 254 nm), a KrF excimer laser (wavelength 248 nm), and an ArF excimer laser (wavelength 193 nm); X-rays such as synchrotron radiation; and charged particle rays such as an electron beam. Lithography using an excimer laser among these is attracting a great attention due to its high output and high efficiency. For this reason, the resists used in lithography also must produce minute patterns of 0.5 mm or less with high sensitivity and high resolution by excimer laser with good reproducibility.
A chemically amplified resist using a radiation sensitive acid generator which generates an acid by being exposed to radiation (hereinafter referred to as “exposure”) and in which the sensitivity of resist is increased by the catalytic action of the acid has been proposed as a resist applicable for use with deep ultraviolet light such as from an excimer laser.
As examples of such chemically amplified resists, a combination of a resin protected by a t-butyl group or t-butoxy carbonyl group and a photoacid generator is disclosed in Japanese Patent Application Laid-open No. 45439/1984. Japanese Patent Application Laid-open No. 52845/1985 discloses a combination of a resin protected by a silyl group and a photoacid generator. Beside these, there are many reports relating to chemically amplified resists such as, for example, a resist which contains a resin having an acetal group and a photoacid generator (Japanese Patent Application Laid-open No. 25850/1990).
Given as examples of the photoacid generator used in these chemically amplified resists are onium salts, such as triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium naphthalenesulfonate, cyclohexylmethyl(2-oxocyclohexyl) sulfonium trifluoromethanesulfonate; sulfonate of 2,6-dinitrobenzyl, tris(methanesulfonyloxy)benzene, and bis(cyclohexylsulfonyl)diazomethane. These conventional photoacid generators are generally unsatisfactory in their sensitivity. Some photoacid generators have relatively high sensitivity, but their overall resist performance, such as resolution and pattern configuration, is not necessarily sufficient.
In view of this situation, there has been a strong desire for the development of a photoacid generator exhibiting high sensitivity and high resolution, and capable of producing fine pattern configuration.
An object of the present invention is therefore to provide a positive tone or negative tone radiation sensitive resin composition capable of producing a superior resist pattern with high sensitivity, high resolution, excellent pattern configuration.
SUMMARY OF THE INVENTION
This object can be achieved in the present invention by a positive-tone radiation sensitive resin composition comprising:
(A) a photoacid generator represented by the following formula (1-1):
wherein R
1
and R
2
may be either same or different and each individually represents an alkyl group containing 1-4 carbon atoms, R
3
represents a hydroxyl group or —OR
4
(wherein R
4
is an organic group having 1-6 carbon atoms), A
1
−
indicates a monovalent anion, a denotes an integer of 4-7, and b is an integer of 0-7; or formula (1-2):
wherein R
5
and R
6
may be either same or different and each individually represents an alkyl group containing 1-4 carbon atoms, R
7
represents a hydroxyl group or —OR
8
(wherein R
8
is an organic group having 1-6 carbon atoms), A
2
−
indicates a monovalent anion, c denotes an integer of 4-7, and d is an integer of 0-7;
(B1) An acid-cleavable group-containing resin which is insoluble or scarcely soluble in alkali, but becomes soluble in alkali when the acid-cleavable group is cleaved; and
(B2) an alkali-soluble resin and an alkali solubility control agent.
The above object can also be achieved in the present invention by a negative-tone radiation sensitive resin composition comprising:
(A) a photoacid generator which is shown by the above formulas (1-1) or (1-2);
(C) an alkali-soluble resin;
(D) a compound capable of cross-linkable the alkali-soluble resin in the presence of an acid.
Other and further objects, features and advantages of the present invention will appear more fully from the following description.
DETAIL DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
The present invention will now be described in detail. Photoacid generator
The photoacid generator (hereinafter referred to as photoacid generator (A)) used in the positive tone or negative radiation sensitive resin composition of the present invention is a compound represented by the above formulas (1-1) or (1-2). This compound chemically change on being irradiated.
In formulas (1-1) and (1-2), as examples of the alkyl group having 1-4 carbon atoms represented by R
1
, R
2
, R
5
, or R
6
, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, and t-butyl group can be given.
As examples of —OR
4
representing R
3
or R
7
representing —OR
8
, alkoxyl groups such as methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, sec-butoxy group, and t-butoxy group; alkoxyalkoxyl groups such as methoxymethoxy group, ethoxymethoxy group, n-propoxymethoxy group, i-propoxymethoxy group, 1-methoxyethoxy group, 1-ethoxyethoxy group, 1-n-propoxyethoxy group, 1-i-propoxyethoxy group, 2-methoxyethoxy group, 2-ethoxyethoxy group, 2-n-propoxyethoxy group, 2-i-propoxyethoxy group, 1-methoxypropoxy group, 2-methoxypropoxy group, 3-methoxypropoxy group, 1-ethoxypropoxy group, 2-ethoxypropoxy group, and 3-ethoxypropoxy group; alkoxy carbonyloxy groups such as methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, i-propoxycarbonyloxy group, n-butoxycarbonyloxy group, i-butoxycarbonyloxy group, sec-butoxycarbonyloxy group, and t-butoxycarbonyloxy group; cyclic acetal group such as 2-tetrahydrofuranyloxy group and 2-tetrahydropyranyloxy group; (substituted)benzyloxy groups such as benzyloxy group, o-methylbenzyloxy group, m-methylbenzyloxy group, p-methylbenzyloxy group, p-t-butylbenzyloxy group, and p-methoxybenzyloxy group; and alkoxy carbonylmethyl groups such as methoxycarbonylmethyl group, ethoxycarbonylmethyl group, n-propoxycarbonylmethyl group, i-propoxycarbonylmethyl group, n-butoxycarbonylmethyl group, i-butoxycarbonylmethyl group, sec-butoxycarbonylmethyl group, and t-butoxycarbonylmethyl group.
As examples of the monovalent anion represented by A
1
−
or A
2
−
, inaddition to sulfonic acid anions originating from sulfonic acid such as trifluoromethanesulfonic acid, nonafluorobutanesulfonic acid, dodecaylbenzenesulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, pyrenesulfonicacid, andcamphorsulfonicacid, BF
4
Iwanaga Shin-ichiro
Iwasawa Haruo
Kajita Toru
Suwa Mitsuhito
Ashton Rosemary E.
Japan Synthetic Rubber Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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