Semiconductor device manufacturing: process – Coating of substrate containing semiconductor region or of... – Insulative material deposited upon semiconductive substrate
Reexamination Certificate
2000-03-29
2001-11-20
Wilczewski, Mary (Department: 2822)
Semiconductor device manufacturing: process
Coating of substrate containing semiconductor region or of...
Insulative material deposited upon semiconductive substrate
C438S781000, C430S312000, C430S313000, C430S325000, C430S330000
Reexamination Certificate
active
06319853
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device wherein minutely isolated resist patterns are formed and the side walls thereof are roughened. More concretely, the present invention relates to a method of forming minutely isolated resist patterns in which a space between patterns and the size of a hole are reduced. The present invention further relates to a method of roughening the side walls of the minutely isolated resist patterns after etching.
2. Background Art
The width of an interconnection runner and the space between interconnection runners required to manufacture a semiconductor device are greatly reduced as the degree of integration of a semiconductor device is increased. Minute patterns are usually formed by forming a resist pattern through use of photolithography and by etching various thin films beneath the resist pattern while using the resist pattern as a mask.
For this reason, photolithography becomes very important in forming a minute pattern. Photolithography comprises a resist coating process, a mask alignment process, an exposure process, and a development process. There is a restriction on the wavelength of light used for exposure, imposing a limitation on miniaturization of the pattern.
Methods described in Japanese Patent Application Laid-open Nos. 6-250379 and 7-134422 have already been proposed as methods of forming minute resist patterns smaller than the limit of wavelength of light for exposure purposes used by the existing photolithography. The methods utilize counter diffusion of resin components contained in first and second resists. Under these methods, the second resist is made of a material which is soluble in an organic solvent capable of dissolving the first resist, resulting in the first resist patterns being deformed.
Under a method used for removing the second resist, the second resist is removed and dissolved through use of a developer capable of generating an acid and dissolving the second resist upon exposure to light [e.g., TMAH (tetra-methyl-ammonium hydroxide)]. When the second resist is exposed to light, the first resist patterns beneath the second resist are also exposed to light and sometimes becomes solubilized. The thus-solubilized first resist patterns can be dissolved in a solution capable of dissolving the second resist. Therefore, there is a high risk of the first resist patterns being dissolved at the time of dissolving and removing the second resist, resulting in a small margin of error in the manufacturing process.
In a case where polyvinyl alcohol disclosed in Japanese Patent Application Laid-open No. 6-250379 is used as a second resist, several problems arise such as a small effect of the second resist or the poor topography of resist patterns produced after treatment. Further, since the second resist is developed through use of only water, the resist is not sufficiently rinsed, thus resulting in development residues, such as specks, being apt to arise in the pattern. Such development residues will cause defects to appear in resist patterns during a subsequent etching process.
As mentioned previously, it has been very difficult to form minute resist patterns smaller than the limit of wavelength of light for exposure purposes used for the existing photolithography, using the existing photolithography.
Although another technique has also been proposed which enables formation of resist patterns smaller than the limit of wavelength of light for exposure purposes, the technique suffers several problems, and hence it is difficult to apply the technique to actual manufacture of a semiconductor device.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a technique of manufacturing minutely isolated resist patterns which enables formation of a minutely isolated or holed pattern smaller than the limit of wavelength of light for exposure purposes.
Another object of the present invention is to provide a method of forming a considerably clean pattern which is free from residues such as specks and which has superior geometry.
Still another object of the present invention is to provide a semiconductor device manufactured through use of the foregoing technique of manufacturing minutely-isolated resist patterns.
According to one aspect of the present invention, in a method of manufacturing a semiconductor device, a first resist pattern is formed which is capable of supplying an acid on a semiconductor substrate by growing a first resist and by forming a pattern on the first resist. A second resist is formed on the first resist pattern, and the second resist is incapable of dissolving the first resist pattern and capable of causing a crosslinking reaction in the presence of an acid. A crosslinked film is formed along the boundary surface between the first resist pattern and the second resist adjoining the first resist pattern by means of the acid supplied from the first resist pattern. A second resist pattern is formed through multi-step processing, wherein non-crosslinked portions of the second resist are developed through use of a solution of high solubility incapable of dissolving the first resist patterns but capable of dissolving the second resist and wherein the substrate is rinsed with a solution of low solubility. Finally, the semiconductor substrate is etched using the second resist patterns as masks.
In another aspect of the present invention, in the semiconductor device manufacturing method, the solution of high solubility is preferably a mixed solution formed by mixing water with alcohol or a water-soluble organic solvent to such an extent as not to dissolve the first resist, and the solution of low solubility is water.
In another aspect, the solution of high solubility contains a surfactant.
In another aspect, the first resist produces an acid upon exposure to light or when subjected to a heat treatment.
In another aspect, the first resist diffuses an acid included therein when subjected to a heat treatment to cause crosslinking reaction at an interface with said second resist.
In another aspect, the first resist produces an acid when exposed to light and when subjected to a heat treatment.
In another aspect, the first resist contains an acid.
In another aspect, the surface of the first resist pattern is processed through use of an acidic liquid or an acidic gas.
In another aspect, the crosslinked film is formed along the surface of a predetermined area of the first resist pattern by selectively exposing the predetermined area to light and by heating the thus-exposed area.
In another aspect, the crosslinked film is formed along the surface of a predetermined area of the first resist pattern by selectively exposing the predetermined area to an electron beam.
In another aspect, the first resist is formed from a mixture composed of novolac resin and a naphthoquinonediazide-based photosensitive agent.
In another aspect, the first resist is a chemically amplified resist which uses a mechanism of producing an acid when the resist is exposed to UV-rays, an electron beam, or X-rays.
In another aspect, the second resist is selected from a group consisting of water-soluble resin, water-soluble resin which causes a crosslinking reaction in the presence of an acid, a water-soluble crosslinking agent, and mixtures thereof.
In another aspect, the water-soluble resin is selected from the group consisting of a polyacrylic acid, polyvinyl acetal, polyvinylpyrrolidone, polyvinyl alcohol, polyethyleneimine, sytrene-maleic anhydride copolymer, polyvinylamine, polyallylamine, oxazoline group-containing water-soluble resins, water-soluble urethane, water-soluble phenol, water-soluble epoxy, water-soluble melamine resins, water-soluble urea resins, alkyd resins, sulfonamide, one type of salt thereof, and a mixture of two or more types of thereof.
In another aspect, the water-soluble crosslinking agent is one type of material or two or more types of materials selected from the group consisting of melamine-based crosslinking age
Ishibashi Takeo
Katayama Keiichi
Toyoshima Toshiyuki
Yasuda Naoki
McDermott & Will & Emery
Mitsubishi Denki & Kabushiki Kaisha
Wilczewski Mary
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