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
1998-06-24
2003-10-28
Baxter, Janet (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
C430S287100, C430S905000, C430S326000, C430S914000
Reexamination Certificate
active
06638683
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive photoresist composition for use in the production of semiconductor IC elements, masks for IC production, printed circuit boards, liquid-crystal panels, etc.
BACKGROUND OF THE INVENTION
Conventional resists comprising a novolak and a naphthoquinonediazide compound are unsuitable for use in pattern formation by lithography using far ultraviolet rays or excimer laser beams, because the novolak and the naphthoquinonediazide show intense absorption in the far ultraviolet region to render the light less apt to reach the resist bottom. Thus, the resist has low sensitivity to give only a tapered pattern.
One means for eliminating the above problem is the chemically amplified resist composition described in, e.g., U.S. Pat. No. 4,491,628 and European Patent 29,139. A chemically amplified positive resist composition is a pattern-forming material in which an acid generates in exposed areas upon irradiation with a radiation such as far ultraviolet rays and this acid catalyzes a reaction that makes the areas irradiated with the actinic rays and the unirradiated areas to differ in solubility in a developing solution to thereby form a pattern on a substrate.
Examples thereof include combinations of a compound which generates an acid upon photodecomposition with an acetal or O,N-acetal compound (see JP-A-48-89003; the term “JP-A” as used herein means an “unexamined published Japanese patent application”), with an orthoester or amidoacetal compound (see JP-A-51-120714), with a polymer having acetal or ketal groups in the backbone (see JP-A-53-133429), with an enol ether compound (see JP-A-55-12995), with an N-acyliminocarbonic acid compound (see JP-A-55-126236), with a polymer having orthoester groups in the backbone (see JP-A-56-17345), with a tertiary alkyl ester compound (see JP-A-60-3625), with a silyl ester compound (see JP-A-60-10247), and with a silyl ether compound (see JP-A-60-37549 and JP-A-60-121446). These combinations show high photosensitivity since they have a quantum efficiency exceeding 1 as the principle.
Another means for eliminating the problem described hereinabove is a system which is stable over long at room temperature but decomposes upon heating in the presence of an acid to become alkali-soluble. Examples thereof include systems comprising a combination of a compound which generates an acid upon exposure to light with an ester having a tertiary or secondary carbon (e.g., t-butyl or 2-cyclohexenyl) or with a carbonic ester compound, as described in, e.g., JP-A-59-45439, JP-A-60-3625, JP-A-62-229242, JP-A-63-27829, JP-A-63-36240, JP-A-63-250642;
Polym. Eng. Sce.,
Vol. 23, p. 12 (1983);
ACS. Sym.,
Vol. 242, p. 11 (1984);
Semiconductor World,
November 1987 issue, p. 91;
Macromolecules,
Vol. 21, p. 1475 (1988); and
SPIE,
Vol. 920, p. 42 (1988). Since these systems also have high sensitivity and show reduced absorption in the deep UV region as compared with the naphthoquinonediazide
ovolak resin systems, they can be effective systems for coping with the utilization of the light source having shorter wavelength.
The chemically amplified positive resist compositions described above are roughly divided into three groups: three-component systems comprising an alkali-soluble resin, a compound which generates an acid upon exposure to a radiation (photo-acid generator), and a dissolution inhibitive compound for the alkali-soluble resin which has acid-decomposable groups; two-component systems comprising a resin having groups which decompose upon reaction with an acid to render the resin alkali-soluble and a photo-acid generator; and hybrid systems comprising a resin having groups which decompose upon reaction with an acid to render the resin alkali-soluble, a low-molecular dissolution inhibitive compound having an acid-decomposable group, and a photo-acid generator.
In JP-A-2-19847 is disclosed a resist composition characterized by containing a resin obtained from poly(p-hydroxystyrene) by protecting all or part of the phenolic hydroxyl groups each with a tetrahydropyranyl group.
In JP-A-4-219757 is disclosed a resist composition characterized by containing a resin obtained likewise from poly(p-hydroxystyrene) by replacing from 20 to 70% of the phenolic hydroxyl groups each with an acetal group.
Moreover, JP-A-5-249682 discloses a photoresist composition containing a similar resin protected with an acetal. In JP-A-8-123032 is disclosed a photoresist composition containing a terpolymer having groups substituted with acetal groups.
Furthermore, JP-A-8-253534 discloses a photoresist composition containing a partly crosslinked polymer having groups substituted with acetal groups.
JP-A-8-15864 discloses a positive resist composition comprising a mixture comprising as a resin component polyhydroxystyrene in which 10 to 60 mol % of hydroxy groups were replaced with t-butoxycarbonyloxy groups and polyhydroxystyrene in which 10 to 60 mol % of hydroxy groups were replaced with ethoxyethoxy groups.
However, these compositions have some problems such as unsatisfactory dimensional reproducibility of isolated patterns and generation of scum at lower parts of patterns after development. Solution of these problems has been desired.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an excellent, chemically amplified positive photoresist composition which has high resolution and improved dimensional reproducibility of isolated patterns.
Another object of the present invention is to provide an excellent, chemically amplified positive photoresist composition which is prevented from generating a scum after development and has high resolution.
As a result of intensive investigations made by the present inventor under these circumstances, it has been found that a positive photoresist composition comprising a combination of two alkali-soluble resin binders each having a substituent having a different specific structure from each other, a compound which generates an acid upon irradiation with actinic rays or a radiation, and a solvent (first photoresist composition) shows high resolution and is effective in eliminating the above-described problem concerning the dimensional reproducibility of isolated patterns, and a positive photoresist composition comprising a combination of an alkali-soluble resin binder substituted with substituents of a specific structure and a nonpolymeric dissolution inhibitive compound having specific functional groups, a compound which generates an acid upon irradiation with actinic rays or a radiation, and a solvent (second photoresist composition) shows high resolution and is effective in eliminating the problem of scum generation described above. The present invention has been completed based on these findings.
(1) The first positive photoresist composition comprises:
(a) Resin A obtained from an alkali-soluble resin containing phenolic hydroxyl groups by replacing from 10 to 80% of the phenolic hydroxyl groups each with a group represented by the following formula (I); (b) Resin B obtained from an alkali-soluble resin containing phenolic hydroxyl groups by replacing from 10 to 80% of the phenolic hydroxyl groups each with a group represented by the following formula (II) or (III); (c) a compound which generates an acid upon irradiation with actinic rays or a radiation; and (d) a solvent,
wherein R
1
represents a substituent selected from alkyl groups having 1 to 4 carbon atoms; W represents either an organic residue containing at least one atom selected from oxygen, nitrogen, sulfur, phosphorus, and silicon atoms or an atomic group selected from the group consisting of an amino group, an ammonium group, and a mercapto group;
n represents a natural number of from 1 to 4; and
R
4
represents a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms.
(2) The second positive photoresist composition comprises:
(a) Resin A obtained from an alkali-soluble resin containing phenolic hydroxyl groups by replacing from 10 to 80% of the phenolic hydroxyl groups each wit
Aoai Toshiaki
Fujimori Toru
Tan Shiro
Baxter Janet
Fuji Photo Film Co. , Ltd.
Lee Sin J.
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