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
1998-07-16
2001-07-31
Ashton, Rosemary E. (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
C430S325000, C430S327000
Reexamination Certificate
active
06268108
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a composition for forming an antireflective coating film and a method for forming a resist pattern using same. More particularly, the present invention relates to a composition for forming an antireflective coating film for preventing the reflection of light from a semiconductor substrate and a method for forming a resist pattern using the composition for forming an antireflective coating film.
BACKGROUND OF THE INVENTION
In the preparation of semiconductor devices such as IC and LSI, it has heretofore been a common practice that various steps such as photolithographic step using a photoresist composition, etching step, impurity diffusion step and wiring step are repeated several times. In the foregoing photolithographic step, a photoresist composition is applied to a semiconductor substrate to form a thin film thereon. The thin film is irradiated with actinic rays through a mask pattern, and then developed to form a resist pattern. As the actinic rays there have been used g-line (436 nm), i-line (365 nm), etc. However, with the enhancement of integration of semiconductor devices, light rays having a shorter wavelength such as far ultraviolet rays and exima laser have been used more and more. The shorter the wavelength of the actinic light rays used, the more light is reflected from the substrate. This causes a great problem that the resist pattern is liable to local strain (notching) or deterioration of dimensional accuracy due to reflected light. Thus, the interposition of an antireflective coating film between the substrate and the resist layer for the purpose of inhibiting the reflection of light has been noted (see JP-B-3-67261 (The term “JP-B” as used herein means an “examined Japanese patent publication”)).
With the reduction of the wavelength of the actinic light rays used, emphasis has been placed on resists having a high resolution more and more. These resists have been extensively studied. However, if a resist composition having a high resolution is applied to a substrate having an antireflective coating film formed thereon, a so-called intermixed layer can be easily formed at the interface of the resist composition layer with the antireflective coating film, causing the lower part of the resist pattern to be bitten or expanded and hence making it impossible to form a resist pattern having an excellent section shape. Thus, good semiconductor devices can be hardly produced. This disadvantage becomes remarkable particularly with a chemically-sensitized resist composition capable of forming a resist pattern having an excellent dimensional accuracy and resolution. In order to eliminate these difficulties, an approach involving heat treatment at temperatures higher than 180° C. has been proposed. However, this approach is disadvantageous in that the dye in the antireflective coating film can be easily sublimated, causing stain in the apparatus and other troubles. Thus, this approach is of no practical use.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a composition for forming an antireflective coating film which is not liable to formation of an intermixed layer between the resist composition layer and the antireflective coating layer.
It is another object of the present invention to provide a method for forming a resist pattern having an excellent dimensional accuracy and section shape using the foregoing composition for forming an antireflective coating film. These and other objects of the present invention will become more apparent from the following detailed description and examples.
The inventors made extensive studies of solution to the foregoing problems. As a result, it was found that the use of a composition for forming an antireflective coating film comprising a compound which produces an acid upon irradiation with actinic rays, a compound which undergoes crosslinking reaction in the presence of an acid and a dye makes it possible to form an antireflective coating film without the necessity of high temperature treatment and inhibit the formation of an intermixed layer, enabling the formation of a resist pattern having an excellent dimensional accuracy and section shape free from bite and expansion of the lower part of the resist pattern by the resist pattern.
Namely, the foregoing objects are accomplished with a composition for forming an antireflective coating film comprising (A) a compound which produces an acid upon irradiation with actinic rays, (B) a compound which undergoes crosslinking reaction in the presence of an acid and (C) a dye and a method for forming a resist pattern which comprises applying the above-specified composition for forming an antireflective coating film to a semiconductor substrate, drying the applied composition, irradiating the entire surface of the dried composition with actinic rays so that the composition undergoes crosslinking reaction to form an antireflective coating film, applying a resist composition to the antireflective coating film, drying the applied resist composition, and then subjecting the resist composition to lithographic processing to form a resist pattern.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be further described hereinafter.
As the compound which produces an acid upon irradiation with actinic rays to be used as the component (A) (hereinafter referred to as “acid generator”) there may be used a known acid generator without any special restriction. Specific examples of such an acid generator include (a) bissulfonyldiazomethanes such as bis(p-toluenesulfonyl)diazomethane, methylsulfonyl-p-toluenesulfonyldiazomethane, 1-cyclohexylsulfonyl-1-(1,1-dimethylethylsulfonyl)diazomethane, bis(1,1-dimethylethylsulfonyl)diazomethane, bis(1-methylethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(2,4-dimethylphenylsulfonyl)diazomethane, bis(4-ethylphenylsulfonyl)diazomethane, bis(3-methylphenylsulfonyl)diazomethane, bis(4-methoxyphenylsulfonyl)diazomethane, bis(4-fluorophenylsulfonyl)diazomethane, bis(4-chlorophenylsulfonyl)diazomethane and bis(4-tert-butylphenylsulfonyl)diazomethane, (b) nitrobenzyl derivatives such as p-toluenesulfonic acid 2-nitrobenzyl, p-toluenesulfonic acid-2,6-dinitrobenzyl and p-trifluoromethyl benzenesulfonic acid-2,4-dinitrobenzyl, (c) aliphatic or aromatic sulfonic acid esters of polyhydroxy compound such as methanesulfonic acid ester of pyrogallol (pyrogalloltrimesylate), benzenesulfonic acid ester of pyrogallol, p-toluenesulfonic acid ester of pyrogallol, p-methoxybenzenesulfonic acid ester of pyrogallol, mesitylenesulfonic acid ester of pyrogallol, benzylsulfonic acid ester of pyrogallol, methanesulfonic acid ester of alkyl gallate, benzenesulfonic acid ester of alkyl gallate, p-toluenesulfonic acid ester of alkyl gallate, p-methoxybenzenesulfonic acid ester of alkyl gallate, mesitylenesulfonic acid ester of alkyl gallate and benzylsulfonic acid ester of alkyl gallate, (d) onium salts such as diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium trifluoromethanesulfonate, (4-methoxyphenyl)phenyliodonium hexafluoroantimonate, (4-methoxyphenyl)phenyliodonium trifluoromethanesulfonate, bis(p-tert-butylphenyl)iodonium tetrafluoroborate, bis(p-tert-butylphenyl)iodonium hexafluorophosphate, bis(p-tert-butylphenyl)iodonium hexafluoroantimonate, bis(p-tert-butylphenyl)iodonium trifluoromethanesulfonate, triphenyl sulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate and triphenylsulfonium trifluoromethanesulfonate, (e) sulfoniuncarbonylalkanes such as 2-methyl-2-(p-toluenesulfonyl)propiophenone, 2-(cyclohexylcarbonyl)-2-(p-toluenesulfonyl)propane, 2-methanesulfonyl-2-methyl-(4-methylthio)propiophenone and 2,4-dimethyl-2-(p-toluenesulfonyl)pentane-3-one, (f) sulfonylcarbonyldiazomethanes such as 1-p-toluenesulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1-methylsulfonyl-4-phenyl-2-butanone, 1-cyclohexylsulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1-cyclohexylsulf
Iguchi Etsuko
Kobayashi Masakazu
Komano Hiroshi
Nakayama Toshimasa
Ashton Rosemary E.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Tokyo Ohka Kogyo Co. Ltd.
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