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
2002-04-10
2004-08-17
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
C430S905000, C430S914000, C430S921000, C430S925000, C430S927000, C430S909000, C430S325000, C430S326000, C430S313000
Reexamination Certificate
active
06777161
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a lower layer resist for a silicon-containing two-layer resist which is used for exposure by an energy ray such as ultraviolet ray, far ultraviolet ray, X ray, electron beam, molecular ray and &ggr; ray, more specifically, the present invention relates to a lower layer resist for a silicon-containing two-layer resist for fine working which is used in the production process of a semiconductor such as IC, for example, at the production of a circuit board or the like.
BACKGROUND OF THE INVENTION
Accompanying higher integration of LSI, the resolution attainable by a conventional single layer resist is limited and there has been proposed a method of forming a fine pattern having a large film thickness and a high form ratio by constructing a resist not in a single layer structure but in a multilayer structure. More specifically, an organic polymer thick film is formed as the first layer and a thin film resist material layer is formed as the second layer thereon. A high energy ray is irradiated on the resist material of the second layer and using the pattern obtained after the development as a mask, the organic polymer of the first layer is anisotropically etched by oxygen plasma etching (O2-RIE) to obtain a pattern having a high rectangular shape property (see, Lin,
Solid State Technology
, Vol. 24, page 73 (1981)). This method is generally called a two-layer resist process and since the second resist layer is a thin film, the obtained lithography performance is expected to surpass that by an ordinary single layer resist.
In this case, since the second resist layer (hereinafter simply referred to as an “upper layer”) must have high resistance against O2-RIE, a silicon-containing polymer is usually used therefor. Many silicon-containing photosensitive compositions using such a polymer have been proposed.
As for the first resist layer (hereinafter simply referred to as a “lower layer”), a method of processing a novolak resin or the like at a high temperature and then curing it is widely employed so as to attain good adhesion to the substrate, good film forming property, high resistance against dry etching, incompatibility with and good adhesion to the upper layer, high light absorption property for the exposure wavelength, and the like. However, since a reaction at a high temperature for a long period of time is necessary, not only the throughput is extremely reduced but also a decomposed material is produced by the high-temperature long-term processing to cause contamination of the apparatus. In order to solve these problems, a method of using the polymer in combination with a thermal acid generator and a crosslinking agent in the lower layer has been proposed. WO00/53645 discloses a combination of a sulfonic acid ester-type thermal acid generator and a crosslinking agent having an epoxy structure and WO00/54105 discloses a combination of a sulfonic acid ester-type thermal acid generator and a crosslinking agent having a melamine skeleton structure. These can be cured within a relatively short time but are disadvantageously poor in the dry etching resistance.
Also, JP-A-2000-321776 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) discloses a combination of a thermal acid generator having a sulfonic acid ester or onium salt structure and a crosslinking agent having a cresol skeleton, however, this composition has a problem in that the film after heat curing is non-uniform in the density and poor in the film thickness uniformity. Thus, improvement is strongly demanded.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a lower layer resist for a silicon-containing two-layer resist used for exposure by an energy ray such as ultraviolet ray, far ultraviolet ray, X ray, electron beam, molecular ray and &ggr; ray, particularly, a lower layer resist for a silicon-containing two-layer resist, which can cope with exposure in the far ultraviolet region at the production of a semiconductor device.
Another object of the present invention is to provide a lower layer resist for a silicon-containing two-layer resist, having excellent dry etching resistance.
Still another object of the present invention is to provide a lower layer resist for a silicon-containing two-layer resist, having excellent film thickness uniformity.
As a result of extensive investigations by taking notice of the above-described various properties, the present inventors have accomplished the present invention. More specifically, the objects of the present invention can be attained by the following constructions:
(1) a lower layer resist composition for a silicon-containing two-layer resist, comprising (a) a phenol-based polymer, (b) a compound capable of generating a sulfonic acid at a temperature of 100° C. or more, (c) a phenol-based acid crosslinking agent having two or more benzene rings and capable of crosslinking with the polymer under the action of an acid, and (d) a solvent;
(2) the lower layer resist composition for a silicon-containing two-layer resist as described in (1), wherein the phenol-based polymer is at least one member selected from a novolak resin and a homopolymer or copolymer having a polyvinyl phenol site;
(3) the lower layer resist composition for a silicon-containing two-layer resist as described in (1) or (2), wherein the phenol-based polymer is a copolymer having a polyvinyl phenol site and at a side chain at least one group selected from the group consisting of a chain hydrocarbon group, an alicyclic hydrocarbon group and a bridged alicyclic hydrocarbon group;
(4) the lower layer resist composition for a silicon-containing two-layer resist as described in any one of (1) to (3), wherein the phenol-based acid crosslinked agent has from 3 to 5 benzene rings;
(5) the lower layer resist composition for a silicon-containing two-layer resist as described in any one of (1) to (4), wherein the compound capable of generating a sulfonic acid is at least one member selected from a secondary or tertiary alcohol ester of sulfonic acid and an iodonium salt of sulfonic acid;
(6) the lower layer resist composition for a silicon-containing two-layer resist as described in any one of (1) to (5), which further contains a nitrogen-containing compound;
(7) the lower layer resist composition for a silicon-containing two-layer resist as described in any one of (1) to (6), which further contains a surfactant;
(8) A pattern-forming method which comprises steps: coating on a substrate a lower layer resist composition for a silicon-containing two-layer resist, comprising (a) a phenol-based polymer, (b) a compound capable of generating a sulfonic acid at a temperature of 100° C. or more, (c) a phenol-based acid crosslinking agent having two or more benzene rings and capable of crosslinking with the polymer under the action of an acid, and (d) a solvent to form a lower (layer) resist layer;
forming on the lower (layer) resist layer an upper layer resist composition to from an upper layer resist layer; and irradiating a high energy ray to form a pattern;
(9) the pattern-forming method as described in (8), wherein the phenol-based polymer is at least one member selected from a novolak resin and a homopolymer or copolymer having a polyvinyl phenol site;
(10) the pattern-forming method as described in (8) or (9), wherein the phenol-based polymer is a copolymer having a polyvinyl phenol site and at a side chain at least one group selected from the group consisting of a chain hydrocarbon group, an alicyclic hydrocarbon group and a bridged alicyclic hydrocarbon group;
(11) the pattern-forming method as described in any one of (8) to (10), wherein the phenol-based acid crosslinked agent has from 3 to 5 benzene rings;
(12) the pattern-forming method as described in any one of (8) to (11), wherein the compound capable of generating a sulfonic acid is at least one member selected from a secondary or tertiary alcohol ester of sulfonic acid and an iodonium salt of sulfonic acid;
(13) the pattern-forming method as descr
Mizutani Kazuyoshi
Yasunami Shoichiro
Ashton Rosemary
Fuji Photo Film Co. , Ltd.
Lee Sin J.
Sughrue & Mion, PLLC
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