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
2001-04-03
2003-03-11
Dawson, Robert (Department: 1712)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C528S012000, C528S036000, C528S037000, C528S038000, C556S460000, C556S479000, C556S458000, C525S100000
Reexamination Certificate
active
06531260
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a polysiloxane and a method of preparing the same, a silicon-containing alicyclic compound, and a radiation-sensitive resin composition containing the polysiloxane suitable for use in microfabrication utilizing radiation.
2. Description of the Background Art
A recent strong demand for high density and highly integrated LSIs accelerates miniaturization of wiring patterns.
Using short wave rays in a lithographic process is one method for miniaturizing wiring patterns. In recent years, deep ultraviolet rays typified by a KrF excimer laser (wavelength: 248 nm) or an ArF excimer laser (wavelength: 193 nm), electron beams, X rays, and the like are being used in place of ultraviolet rays such as g-line (wavelength: 436 nm), 1-line (wavelength: 365 nm), etc. Use of an F2 excimer laser (wavelength: 157 nm) is also being studied.
Novolac resins, poly(vinylphenol), and the like have been used as resin components for conventional resist compositions. However, because these resins exhibit strong absorbance at a wavelength of 193 nm due to inclusion of aromatic rings in the structure, a lithographic process by an ArF excimer laser, for example, using these resins cannot provide high accuracy corresponding to high photosensitivity, high resolution, and a high aspect ratio.
Therefore, a resin for use in a resist, transparent to a wavelength of 193 nm or less, particularly to a wavelength of 157 nm, and exhibiting excellent dry etching resistance equivalent to or better than aromatic rings has been desired. A polysiloxane is one such a polymer. R. R. Kunz at al. of the MIT have reported their research results showing excellent transparency of a polysiloxane at a wavelength of 193 nmor less, particularly at 157 nm, commenting on superiority of this polymer as a resist in a lithographic process using radiation with a wavelength of 193 nmor less (J. Photopolym. Sci. Technol., Vol. 12, No.4, 1999). Moreover, polysiloxanes are known to exhibit excellent dry etching properties. In particular, a resist containing polyorganosilsesquioxane having a ladder structure is known to possess high plasma resistance.
Several resist materials using a siloxane polymer have also been reported. For example, Japanese Patent Publication No. 323611/1993 discloses a radiation-sensitive resin composition comprising a polysiloxane having an acid-dissociable group such as a carboxylic acid group, phenol ether group, etc., on the side chain, bonded to a silicon atom via one or more carbon atoms. Japanese Patent Application Laid-open No. 160623/1996 discloses a positive tone resist using poly(2-carboxyethylsiloxane) in which the carboxyl group is protected with an acid-dissociable group such as a t-butyl group. Japanese Patent Application Laid-open No. 60733/1999 discloses a resist resin composition in which a polyorganosilsesquioxane providing an acid-decomposable ester group is used. However, resist materials using these conventional siloxane polymers containing an acid-dissociable group have not been satisfactory in producing basic properties in a resist such as transparency to radiation, resolution, developability, and the like.
Japanese Patent Publication No. 302382/1999 discloses a siloxane polymer having a non-aromatic monocyclic or polycyclic hydrocarbon group or a bridged cyclic hydrocarbon group containing a carboxyl group on the side chain, at least part of the carboxyl group being replaced by a group unstable to an acid, and a resist material containing such a polymer. This resist material exhibits small absorbance of a KrF excimer laser (wavelength: 248 nm) or an ArF excimer laser (wavelength: 193 nm), produces fine pattern configuration, and excels in properties such as sensitivity, resolution, dry etching resistance, etc. However, even if the above-mentioned siloxane polymer is considered, there are few siloxane polymer useful as a resin component of a resist material. A new siloxane polymer which can provide a resist material effectively sensing radiation with a short wavelength, exhibiting high transparency to radiation and superior anti-dryetching properties, and excelling in basic resist properties, and a silicon compound which can produce such a siloxane polymer are important subjects of development in view of the fast advance in microprocessing technologies for semiconductors.
Therefore, an object of the present invention is to provide a novel polysiloxane useful as a resin component for a resist material effectively sensing radiation with a short wavelength, typified by a KrF excimer laser (wavelength: 248 nm), and an ArF excimer laser (wavelength: 193 nm), and an F2 excimer laser (wavelength: 157 nm), exhibiting high transparency to radiation and superior dry etching properties, and excelling in basic resist properties required for resist materials such as high sensitivity, resolution, developability, etc.; a method of preparing such a polysiloxane; a silicon-containing alicyclic compound providing this polysiloxane; and a radiation-sensitive resin composition comprising this polysiloxane.
Therefore, an object of the present invention is to provide a novel polysiloxane useful as a resin component for a resist material effectively sensing radiation with a short wavelength, typified by a KrF excimer laser (wavelength: 248 nm), and an ArF excimer laser (wavelength: 193 nm), and an F2 excimer laser (wavelength: 157 nm), exhibiting high transparency to radiation and superior dry etching properties, and excelling in basic resist properties required for resist materials such as high sensitivity, resolution, developability, etc.; a method of preparing such a polysiloxane; a silicon-containing alicyclic compound providing this polysiloxane; and a radiation-sensitive resin composition comprising this polysiloxane.
SUMMARY OF THE INVENTION
The present invention provides a polysiloxane having the structural unit (I) and/or structural unit (II) and structural unit (III), shown in the following formula (1), and having a polystyrene-reduced weight average molecular weight determined by gel permeation chromatography (GPC) in the range of 500-1,000,000 (this polysiloxane is hereinafter referred to as “polysiloxane (1)”),
wherein A
1
and A
2
individually represent a monovalent organic group having an acid-dissociable group which dissociates by an action of an acid; R
1
represents a hydrogen atom, a monovalent hydrocarbon group having 1-20 carbon atoms, a monovalent halogenated hydrocarbon group having 1-20 carbon atoms, a halogen atom, or a primary, secondary, or tertiary amino group; and R
2
represents a monovalent hydrocarbon group having 1-20 carbon atoms, a monovalent halogenated hydrocarbon group having 1-20 carbon atoms, a halogen atom, or a primary, secondary, or tertiary amino group.
The present invention further provides a radiation-sensitive resin composition comprising: (a) a resin which comprises an alkali soluble or alkali low soluble polysiloxane copolymer, having the above structural unit (I) and/or structural unit (II) and structural unit (III), having a polystyrene-reduced weight average molecular weight determined by gel permeation chromatography (GPC) in the range of 500-1,000,000, and becoming soluble in alkali when an acid-dissociable group dissociates, and (b) a photoacid generator.
The present invention further provides a silicon-containing alicyclic compound represented by the following formula (2-A) or (2-B) (hereinafter referred to as “silicon-containing alicyclic compound (2)”),
wherein R individually represents a hydrogen atom or a methyl group; R
1
individually represents a hydrogen atom, a monovalent hydrocarbon group having 1-20 carbon atoms, a monovalent halogenated hydrocarbon group having 1-20 carbon atoms, a halogen atom, or a primary, secondary, or tertiary amino group; and R
3
individually represents a monovalent hydrocarbon group having 1-20 carbon atoms, a monovalent halogenated hydrocarbon group having 1-20 carbon atoms, or the group of the following formula (i),
wherein X individuall
Hayashi Akihiro
Iwasawa Haruo
Nishiyama Satoru
Shimokawa Tsutomu
Dawson Robert
JSR Corporation
Kelber Steven B.
Peng Kuo Liang
Piper Rudnick LLP
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