The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 27, 2001
Filed:
Mar. 11, 1999
Pascal Costaganna, Chailly en Biere, FR;
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method of plasma etching a Si3N4 masked tungsten silicide layer down to an underlying doped polysilicon layer in the gate conductor stack formation process is disclosed. The method is performed in a plasma etcher and the etching mixture contains C12, HCl and O2 wherein the C12/HCl ratio is approximately equal to 4.7 and the oxygen flow varies between 20 and 30 sccm, 25 sccm being the optimal value. A slight overetching of the underlying doped polysilicon layer with this mixture is recommended. The etching method of the present invention preserves the thickness and integrity of the top Si3N4 masking layer that are essential elements for the successful completion of the remaining steps of the gate conductor stack formation process.