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:
Jan. 07, 1997
Filed:
Dec. 22, 1994
Virinder S Grewal, Fishkill, NY (US);
Siemens Aktiengesellschaft, Munich, DE;
Abstract
A method of plasma etching a gate stack on silicon with a chlorine-containing plasma precursor gas in a vacuum chamber fitted with an electrically conductive planar coil disposed outside the chamber and adjacent to a dielectric window mounted in a wall of the chamber, the conductive planar coil coupled to a first radiofrequency source that matches the impedance of the source to the coil, and a second radiofrequency source coupled to a substrate support mounted in the chamber in a direction parallel to the planar coil which comprises limiting the power during etching to 0-200 watts from the first radiofrequency source and to 50-200 watts from the second radiofrequency source. The resultant etch is anisotropic, and avoids charging of the substrate to be etched. When the gate stack comprises conductive polysilicon, the preferred plasma precursor etch gas is a mixture of hydrogen chloride and chlorine, when a highly selective etch is obtained.