Method of etching polysilicon using a thin oxide mask formed on the polysilicon while doping
AssigneeYamaha Corporation
InventorSuguru Tabara
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Abstract
A polysilicon layer is deposited on a gate insulating film covering the surface of a semiconductor substrate, and thereafter the polysilicon layer is subjected to an impurity doping process in an oxidization atmosphere with heating, to reduce the resistance of the polysilicon layer, and to oxidize the surface of the polysilicon layer and form a silicon oxide film. The silicon oxide film is selectively etched to leave an etching mask. Thereafter, the polysilicon layer is selectively etched to leave an electrode layer or wiring layer by using etching gas not containing carbon and fluorine and using the etching mask. It is possible to obtain a high etching selection ratio with simple processes.
Claims16
A method of manufacturing a semiconductor device comprising the steps of:
- (a) forming a polysilicon layer on an insulative surface of a substrate;
- (b) doping an impurity into said polysilicon layer in an oxidization atmosphere with heating, to reduce a resistance of said polysilicon layer and to oxidize a surface of said polysilicon layer and form a particle-less silicon oxide film thereon;
- and
- (c) selectively etching said silicon oxide film to form an etching mask consisting solely of a remaining silicon oxide film formed in said step (b), and selectively etching said polysilicon layer through said etching mask to leave an electrode layer or wiring layer by using a carbon-free and fluorine-free etching gas.
A method of manufacturing a semiconductor device comprising the steps of:
- (a) providing a substrate;
- (b) forming a polysilicon layer on the substrate;
- (c) doping an impurity into the polysilicon layer;
- (d) concurrently with the step (c), forming a particle-less silicon oxide film on the polysilicon layer;
- (e) forming a patterned mask consisting solely of the remaining silicon oxide film formed in step (d);
- and
- (f) etching the polysilicon layer through the patterned mask of the silicon oxide film.
A method of manufacturing a semiconductor device comprising the steps of:
- (a) forming a polysilicon layer on a surface of a substrate;
- (b) doping an impurity into said polysilicon layer in an oxidization atmosphere with heating so that a surface of said polysilicon layer is oxidized to form a silicon oxide film;
- and
- (c) selectively etching said silicon oxide film to form a silicon oxide etching mask consisting solely of the remaining silicon oxide film formed in step (b) and selectively etching said polysilicon layer through said silicon oxide etching mask using a carbon-free and fluorine-free etching gas to leave an electrode layer or wiring layer.
Dependencies are inferred from the claim text.