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
2000-12-21
2002-12-17
Chu, John S. (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
C430S910000
Reexamination Certificate
active
06495306
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a chemical amplifying type positive resist composition used in the minute processing of a semiconductor.
In general, a lithography process using a resist composition has been adopted in the minute processing of a semiconductor. In lithography, the resolution can be improved with a decrease in wavelength of exposure light in principle as expressed by the equation of Rayleigh's diffraction limited. A g-line with a wavelength of 436 nm. an i-line with a wavelength of 365 nm, and a KrF excimer laser with a wavelength of 248 nm have been adopted as exposure light sources for lithography used in the manufacture of a semiconductor. Thus, the wavelength has become shorter year by year. An ArF excimer laser having a wavelength of 193 nm is considered to be promising as a next-generation exposure light source.
A lens used in an ArF excimer laser exposure machine or an exposure machine using a light-source of shorter wave-length has a shorter lifetime as compared with lenses for conventional exposure light sources. Accordingly, the shorter time required for exposure to ArF excimer laser light is desirable. For this reason, it is necessary to enhance the sensitivity of a resist. Consequently, there has been used a so-called chemical amplifying type resist, which utilizes the catalytic action of an acid generated due to exposure, and contains a resin having a group cleavable by the acid.
It is known that, desirably, resins used in a resist for ArF excimer laser exposure have no aromatic ring in order to ensure the transmittance of the resist, but have an alicyclic ring in place of an aromatic ring in order to impart a dry etching resistance thereto.
It is known that, desirably, resins used in a resist for ArF excimer laser exposure have no aromatic ring in order to ensure the transmittance of the resist, but have an alicyclic ring in place of an aromatic ring in order to impart a dry etching resistance thereto. Various kinds of resins such as those described in Journal of Photopolymer Science and Technology, Vol. 9, No.. 3, pages 387-398 (1996) by D. C. Hofer, are heretofore known as such resins. However, conventionally known resins have a problem that peeling of f of a pattern tends to occur due to insufficient adhesion at development especially when the polarity is insufficient.
Journal of Photopolymer Science and Technology, Vol. 9, No. 3, pages 475-487 (1996) by S. Takechi et al., and JP-A-9-73173 reported that when a polymer or copolymer of 2-methyl-2-adamantyl methacrylate is used as a resin of a chemical amplifying type, 2-methyl-2-adamantyl is cleaved by the action of an acid to act as a positive type, and high dry etching resistance and high resolution as well as good adhesion to a substrate can be attained .
Generally, a resin having an alicyclic ring exhibits a high hydrophobicity and hence does not have a favorable affinity with a developer, which is an aqueous alkali. When the affinity with such a developer is unsatisfactory, uniform development cannot be achieved with the result that the dimensional uniformity of a resulting pattern is affected or a defective development occurs.
An object of the present invention is to provide a chemically amplified positive resist composition containing a resin component and an acid generating agent which is suitable for use in excimer laser lithography utilizing ArF, KrF or the like, and is satisfactory in various resist performance characteristics such as sensitivity, resolution, and adhesion to a substrate while exhibiting an excellent affinity (wettability) with respect to an alkali developer.
JP-A-10-274852 has reported that the use of a resin having a butyrolactone residue in part of a polymeric unit thereof for a chemically amplified positive resist composition improves the adherence of the resist composition to a substrate. Also, JP-A-11-305444 has reported that the use of a resin having polymeric units derived from 2-alkyl-2-adamantyl (meth)acrylate and from maleic anhydride, respectively, for a chemically amplified resist composition improves the adherence of the resist composition to a substrate.
The inventors of the present invention have discovered the fact that the adhesion of a chemically amplified positive resist composition to a substrate is improved also by the use of a polymer having a polymeric unit derived from 2-alkyl-2-adamantyl (meth)acrylate and a polymeric unit derived from 3-hydroxy-1-adamantyl (meth)acrylate as a resin in the resist composition, and have filed Japanese Patent Application No. 11-238542. The inventors have further discovered the fact that the use of a resin including a polymeric unit derived from hydroxystyrene and a polymeric unit derived from 3-hydroxy-1-adamantyl methacrylate improves the resolution and exposure latitude of the resulting resist composition, and have filed Japanese Patent Application No.11-28895. As a result of further study based on these discoveries and knowledge, the inventors of the present invention has further discovered the fact that a resist composition is obtained which is superior in resist performance characteristics such as sensitivity, resolution and adhesion to a substrate while exhibiting an improved hydrophillicity, hence, an improved wettability with an alkali developer by using a resin containing a polymeric unit of high polarity having a specified adamantane structure in the resist composition. The present invention has been completed based on this discovery.
SUMMARY OF THE INVENTION
The present invention provides a chemically amplified positive resist composition comprising
a resin (X) which has a polymeric unit (a) derived from dihydroxy-1-adamantyl (meth)acrylate and a polymeric unit (b) derived from 2-alkyl-2-adamantyl (meth)acrylate, and which, per se, is insoluble or slightly soluble in alkali but becomes soluble in alkali due to an action of acid; and an acid generating agent (Y).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The resin (X), per se, is insoluble or slightly soluble in alkali but becomes soluble in alkali when subjected to an action of acid. The resin (X) contains a polymeric unit(a) derived from dihydroxy-1-adamantyl (meth)acrylate and a polymeric unit(b) derived from 2-alkyl-2-adamantyl (meth)acrylate. The polymeric unit(a) derived from dihydroxy-1-adamantyl (meth)acrylate is represented by the following formula (I):
where R
1
represents hydrogen or methyl. Representative examples of this polymeric unit include a polymeric unit derived from 3,5-dihydroxy-1-adamantyl (meth)acrylate represented by the following formula (Ia):
wherein R
1
is as defined above.
3,5-Dihydroxy-1-adamantyl (meth)acrylate, from which the polymeric unit of the formula (Ia) is derived, is commercially available but may be prepared by hydrolyzing 1,3,5-tribromoadamantane into 1,3,5-trihydroxyamadantane which is then reacting with acrylic acid, methacrylic acid, or their halide.
The resin (X) has the polymeric unit(b) derived from 2-alkyl-2-adamantyl (meth)acrylate along with the polymeric unit(a) derived from dihydroxy-1-adamantyl (meth)acrylate. In general, resins for use in chemically amplified positive resists are, per se, insoluble or slightly soluble in alkali but become soluble in alkali after a group forming part of such a resin has been cleaved due to an action of acid. In the present invention, the group which is cleavable due to an action of acid is 2-alkyl-2-adamantyl, and the polymeric unit(b) derived from 2-alkyl-2-adamantyl (meth)acrylate is a polymeric unit having an acid unstable group.
The polymeric unit derived from 2-alkyl-2-adamantyl (meth)acrylate can be represented by the following formula (II):
wherein R
2
represents hydrogen or methyl, and R
3
represents an alkyl.
Since 2-alkyl-2-adamantyl in the polymeric unit of the formula (II) derived from 2-alkyl-2-adamantyl (meth)acrylate is cleavable due to an action of acid, this unit contributes to an enhancement in the solubility in alkali of a film of the resist having undergone exposure, and the resist containing a resin h
No affiliations
Birch & Stewart Kolasch & Birch, LLP
Chu John S.
LandOfFree
Chemically amplified positive resist composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Chemically amplified positive resist composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chemically amplified positive resist composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2957194