Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-08-26
2001-05-29
Lipman, Bernard (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S326800, C525S326900, C525S327400, C525S327500, C525S327600, C525S328800, C525S340000, C525S341000, C525S343000, C525S348000, C525S351000, C526S270000, C526S281000
Reexamination Certificate
active
06239231
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a chemical amplifying type positive resist composition used in the minute processing of a semiconductor.
PRIOR ART
A lithography process using a resist composition has been adopted in the minute processing of a semiconductor. In the lithography processing, the resolution can be improved with a decrease in wavelength of exposure light in principle as expressed by the expression 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 of the exposure light source 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 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 in the lithography process is desirable, and, for reducing the exposure time, higher sensitivity of a resist has been desired. 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 action of an acid.
It is desirable that 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 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 known for the resins usable in a resist for ArF excimer laser exposure. However, conventionally known resins have a problem that peeling off of a pattern tends to occur due to insufficient adhesion at development.
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 high dry etching resistance and high resolution as well as good adhesion to a substrate can be attained by using a chemical amplifying type resist comprising a polymer or copolymer of 2-methyl-2-adamantyl methacrylate as the resin, in which 2-methyl-2-adamantyl is cleaved by the action of an acid to act as an positive type.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a chemical amplifying type positive resist composition which comprises a resin component and an acid generator, and is suitable for excimer laser lithography of ArF, KrF, or the like, wherein various resist performances such as sensitivity and resolution are good and especially the adhesion to a substrate is excellent.
The present inventors have previously discovered that the adhesion to a substrate is improved by using a chemical amplifying type positive resist composition comprising a resin having a butyrolactone residue in a part of its polymerization unit, or a resin having a polymerization unit of 2-alkyl-2-adamantyl (meth)acrylate and a polymerization unit of maleic anhydride, and have filed patent applications as JP-A-10-12406 and JP-A-10-191559. The present inventors have further conducted a study, and, as a result, have found that resins having a polymerization unit of a specific structure of adamantane series and a certain high polarity polymerization unit are effective for improving the adhesion to a substrate. Thus, the present invention was completed.
The present invention provides a chemical amplifying type positive resist composition which comprises a resin(1) having a polymerization unit of 2-alkyl-2-adamantyl (meth)acrylate, and a polymerization unit of a monomer selected from 3-hydroxy-1-adamantyl (meth)acrylate and (meth)acrylonitrile; and an acid generator.
The polymerization unit of 2-alkyl-2-adamantyl (meth)acrylate herein cited means a unit in the polymer formed by the polymerization of 2-alkyl-2-adamantyl acrylate or 2-alkyl-2-adamantyl methacrylate. The polymerization unit of 3-hydroxy-1-adamantyl (meth)acrylate means a unit in the polymer formed by the polymerization of 3-hydroxy-1-adamantyl acrylate or 3-hydroxy-1-adamantyl methacrylate. Further, the polymerization unit of (meth)acrylonitrile means a unit in the polymer formed by the polymerization of acrylonitrile or methacrylonitrile. These units are represented by the following formulae (I) to (III), respectively:
wherein R
1
represents hydrogen or methyl, and R
2
represents alkyl.
wherein R
3
represents hydrogen or methyl.
wherein R
4
represents hydrogen or methyl.
Therefore, the resin(1) has the unit of the above-described formula (I), and one or both of the units of the above-described formulae (II) and (III). The resin(1) may also have a polymerization unit of &agr;-methacryloyloxy-&ggr;-butyrolactone or a polymerization unit of maleic anhydride. The polymerization unit of &agr;-methacryloyloxy-&ggr;-butyrolactone herein cited means a unit in the polymer formed by the polymerization of &agr;-methacryloyloxy-&ggr;-butyrolactone. The polymerization unit of maleic anhydride means a unit in the polymer formed by the polymerization of maleic anhydride. These units are represented by the following formulae (IV) and (V), respectively:
Among the polymerization units of 2-alkyl-2-adamantyl (meth)acrylate represented by the formula (I), the polymerization unit in which R
1
is methyl, and R
2
is ethyl, i.e., the polymerization unit of 2-ethyl-2-adamantyl methacrylate represented by the following formula (Ia) is important.
This polymerization unit of 2-ethyl-2-adamantyl methacrylate of formula (Ia) can be combined with at least one of the polymerization units selected from the polymerization unit of 3-hydroxy-1-adamantyl (meth)acrylate represented by the above-described formula (II), the polymerization unit of (meth)acrylonitrile represented by the above-described formula (III), the polymerization unit of &agr;-methacryloyloxy-&ggr;-butyrolactone represented by the above-described formula (IV), and the polymerization unit of maleic anhydride represented by the above-described formula (V) to form a resin usable in a chemical amplifying type positive resist. Therefore, the present invention also provides a chemical amplifying type positive resist composition which comprises a resin(2) having a polymerization unit of 2-ethyl-2-adamantyl methacrylate, and a polymerization unit of a monomer selected from 3-hydroxy-1-adamantyl (meth)acrylate, (meth)acrylonitrile, &agr;-methacryloyloxy-&ggr;-butyrolactone, and maleic anhydride; and an acid generator. That is, the resin(2) has the unit of the formula (Ia), and one or a plurality of the units of the formulae (II), (III), (IV), and (V).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The resin(1) has the polymerization unit of 2-alkyl-2-adamantyl (meth)acrylate represented by the formula (I), and one or both of the polymerization unit of 3-hydroxy-1-adamantyl (meth)acrylate represented by the formula (II) and the polymerization unit of (meth)acrylonitrile represented by the formula (III). The resin(1) may optionally have the polymerization unit of &agr;-methacryloyloxy-&ggr;-butyrolactone represented by the formula (IV) and/or the polymerization unit of maleic anhydride represented by the formula (V). Therefore, the resin(1) can be produced by conducting a copolymerization of 2-alkyl-2-adamantyl (meth)acrylate, and one or both of 3-hydroxy-1-adamantyl (meth)acrylate and (meth)acrylonitrile, and optionally &agr;-methacryloyloxy-&ggr;-butyrolactone and/or maleic anhydride.
Among these monomers, 2-alkyl-2-adamantyl (meth)acrylate can generally be produced by the reaction of 2-alkyl-2-adamantanol or a metallic salt thereof and acrylic acid halide or methacrylic acid halide. 3-Hydroxy-1-adamantyl (meth)acrylate can be produced by hydrolyzing 1,3-dibromoadamantane to prepare 1,3-dihy
Araki Karou
Fujishima Hiroaki
Uetani Yasunori
Birch & Stewart Kolasch & Birch, LLP
Lipman Bernard
Sumitomo Chemical Company Limited
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