Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making electrical device
Reexamination Certificate
1999-08-10
2001-01-30
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making electrical device
C430S203000, C430S313000, C430S328000, C430S329000, C430S330000
Reexamination Certificate
active
06180320
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device having fine patterns and a semiconductor device manufactured by the method. More particularly, the present invention relates to a method of forming a resist pattern used for micro-processing of an LSI semiconductor element, a liquid crystal display panel, or the like. Further specifically, the present invention relates to a method of forming a highly-accurate fine resist pattern.
2. Background Art
FIG. 14
shows resist patterns which are formed on an underlying layer
21
according to a conventional method by exposing the layer to light through a mask held at an optimum focal point by a stepper. In
FIG. 14
, reference numeral
22
designates a resist pattern having a line width broader than the wavelength of exposing light from the light source of the stepper, and
23
designates a fine resist pattern having a line width narrower than the wavelength of exposing light from the light source of the stepper. As mentioned above, in a case where the underlying layer is exposed to light through the mask held at an optimum focal point, even the existing method enables a resist pattern to be formed substantially faithfully.
FIG. 15
shows resist patterns which are formed on the underlying layer
21
according to the existing method by exposing the layer to light through a mask held out of focus. In
FIG. 15
, reference numeral
22
′ designates a resist pattern having a line width broader than the wavelength of exposing light from the light source of the stepper, and reference numeral
23
′ designates a fine resist pattern having a line width narrower than the wavelength of exposing light from the light source of the stepper. In a case where the underlying layer is exposed to light through the mask held out of focus, no problems are encountered in the formation of the resist pattern
22
′ having a line width broader than the wavelength of exposing light from the light source of the stepper. In contrast, in a case where the fine resist pattern
23
′ having a line width narrower than the wavelength of exposing light from the light source is formed, there arises a problem that the line width of a resultant pattern becomes narrower.
FIG. 16
is a plot showing the relationship between the dimension of the resist pattern and defocus for the purpose of explaining the foregoing problem. As designated by line
22
a
shown in
FIG. 16
, in a case where a resist pattern of great size is formed, no dimensional variations arise even if the mask of the stepper is slightly defocused. In contrast, as designated by curved line
23
a
shown in
FIG. 16
, in a case where a fine resist pattern smaller than the wavelength of exposing light from the light source of the stepper is formed, and if the mask of the stepper is defocused, significant dimensional variations arise, resulting in a resist pattern of undesirable size.
As mentioned above, at the time of formation of a fine resist pattern, the existing photolithography technique has the disadvantage of being incapable of stably forming a resist pattern.
Accordingly, the object of the present invention is to stably form a fine resist pattern smaller than the limit of the wavelength of exposing light by processing photoresist through a chemical mechanism such as diffusion of an acid or decomposition of photoresist.
Another object of the present invention is to provide a method of manufacturing a semiconductor device which uses the thus-formed fine resist pattern, as well as a semiconductor device having the fine pattern manufactured by the method.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, in a method of manufacturing a semiconductor, a resist pattern is formed on a semiconductor underlying layer disposed on a semiconductor substrate through use of an acid catalyst chemically-amplified photoresist. An organic film organic film containing an acid component or a base component is formed on the surface of the semiconductor underlying layer including the resist pattern. The organic film is thermally-treated to diffuse the acidic component or the base component thereby rendering the surface layer of the resist pattern soluble in an alkaline developer. And, the thermally-treated organic film and the surface layer of the resist pattern is removed through use of the alkaline developer thereby reducing the resist pattern.
In the method, an acidic polymer or a base polymer may be preferably used to form the organic film containing the acidic component or the base component.
In another aspect of the present invention, in the semiconductor device manufacturing method, a polymer having an acidic component added thereto may be used as the organic film containing the acidic component. Alternatively, a polymer having an base component added thereto may be used as the organic film containing the base component.
According to another aspect of the present invention, in a method of manufacturing a semiconductor device, a resist pattern is formed on a semiconductor underlying layer disposed on a semiconductor substrate through use of an acid catalyst chemically-amplified photoresist. An organic film, which produces an acid or a base on exposure to light, is formed on the surface of the semiconductor underlying layer including the resist pattern. The organic film is exposed to light to produce an acid therein. The organic film is thermally-treated to diffuse the acid or the base thereby rendering the surface layer of the resist pattern soluble in an alkaline developer. And, the organic film and the surface layer of the resist pattern is removed through use of the alkaline developer thereby reducing the resist pattern.
In another aspect, in the method, the organic film which produces an acid or a base on exposure to light may be formed preferably by addition of an photosensitive acid generator or a photosensitive base generator to a polymer.
REFERENCES:
patent: Re. 35821 (1998-06-01), Niki et al.
patent: 5670299 (1997-09-01), Urano et al.
patent: 6054254 (2000-04-01), Sato et al.
patent: 4-139826 (1992-05-01), None
patent: 8-6256 (1996-01-01), None
Ishibashi Takeo
Miyagi Tadashi
Saito Takayuki
Sugino Kanji
Toyoshima Toshiyuki
McDermott & Will & Emery
Mitsubishi Denki & Kabushiki Kaisha
Schilling Richard L.
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