Solid state devices formed by differential plasma etching of resists
AssigneeBell Telephone Laboratories, Incorporated
InventorGary N. Taylor
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Abstract
A process of dry etching to form negative resist patterns is described. A host polymer is mixed with one or more monomers capable of being locked into place by electromagnetic radiation and is deposited as a film on a substrate. The film is then selectively irradiated, and then fixed by heating, or vacuum, or both, and etched by means of an oxygen plasma. The rate of removal is higher in the unirradiated region than in the irradiated region, yielding a negative resist pattern. A sensitizer may be added to allow use of various radiation wavelengths. The desirable properties of monomer and host polymer materials are discussed, and specific compositions given of aromatic monomers, silicon containing monomers, and chlorinated polymers.
Claims34
A method of producing a solid state device including at least one pattern delineation step by steps comprising:
- (a) selectively irradiating a resist film on a substrate with actinic radiation;
- (b) treating said film to fix the pattern;
- and
- (c) exposing said film to a plasma to produce a negative resist pattern;
- the invention characterized in that said film comprises a polymer and at least one type of monomer, and characterized further in that the step of selectively irradiating the film locks the monomer or monomers in the portions of the film that are selectively irradiated, the step of treating the film reduces the amount of unlocked monomer or monomers in the film, and the step of exposing the film to a plasma removes the unirradiated portion of the film at a faster rate than the irradiated portion due to the presence of the locked monomer or monomers in the irradiated portion of the film, so that the differential etch ratio is at least 1.05.
A method of producing a solid state device including at least one pattern delineation step by steps comprising:
- (a) selectively irradiating a resist film on a substrate with actinic X-ray radiation;
- (b) treating said film to fix the pattern;
- and
- (c) exposing said film to a plasma comprising oxygen to produce a negative resist pattern;
- the invention characterized in that said film comprises a chlorinated acrylic or methacrylic polymer and at least one type of aromatic monomer having one or more unsaturated polymerizable functional groups, and characterized further in that the step of selectively irradiating the film locks the monomer or monomers into said polymer in those portions of the film that are selectively irradiated, the step of treating the film reduces the amount of unlocked monomer or monomers in the film, and the step of exposing the film to a plasma comprising oxygen removes the unirradiated portion of the film at a faster rate than the irradiated portion due to the presence of the locked monomer or monomers in the irradiated portion of the film, so that the differential etch ratio is at least 1.05.
Dependencies are inferred from the claim text.