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US 4,353,777 AGranted
Selective plasma polysilicon etching
AssigneeLFE Corporation
InventorAdir Jacob
Life of this patent
Estimating the term…
Abstract
A process for etching polysilicon material preferentially over silicon oxide. The process is anisotropic and employs a moderate to low pressure of Freon 11 (CFCl.sub.3) in an RF plasma discharge. In a second embodiment helium is mixed with the Freon 11 to inhibit degradation of the photoresist mask.
Claims6
Process for selectively etching polysilicon material comprising the steps of:
- (a) placing polysilicon material within a reactor chamber, and
- (b) exposing said polysilicon material within the chamber to a gas plasma at a pressure between 50 and 150 microns Hg for etching, wherein said gas plasma consists essentially of RF discharge CFCl.sub.3.
A process for fabrication of a semiconductor device having a polysilicon layer and a silicon oxide layer including the step of preferential etching of said polysilicon layer, where said preferential etching of said polysilicon layer comprises the steps of,
- (a) placing said semiconductor device within a reactor chamber,
- (b) exposing said semiconductor device within said reaction chamber to etchant gas consisting essentially of CFCl.sub.3 at a pressure between 50 and 150 microns Hg.
Dependencies are inferred from the claim text.