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:
Jul. 12, 1983
Filed:
Nov. 12, 1981
David J Harra, Santa Cruz, CA (US);
Varian Associates, Inc., Palo Alto, CA (US);
Abstract
A method for etching a semiconductor wafer on an RF etch table employs a succession of different biases on an extension member positioned adjacent the periphery of the table. The extension member is electrically conductive, but is insulated from the etch table. The extension member is positioned with respect to the periphery of the table in a manner such that the plasma sheath induced above the etch table is continued beyond the periphery of the table, thereby eliminating the focusing of ions on the edges of an item being etched on the table. As different bias voltages are applied to the extension member, different etch profiles are experienced on the semiconductor wafer. The aggregation of etch profiles produces a more uniform overall etch.