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:
May. 09, 2000
Filed:
Jun. 18, 1999
Brett C Richardson, San Ramon, CA (US);
Tuan Ngo, Milpitas, CA (US);
Lam Research Corporation, Fremont, CA (US);
Abstract
Variable reactances of a matching network connected between an r.f. source and a plasma load of a vacuum plasma chamber processing a workpiece are varied so a tendency of the plasma to change in an unstable manner which can adversely affect processing of the workpiece is avoided while matching is approached. The plasma tendency to change in an unstable manner is detected by monitoring an electrical parameter resulting from r.f. current flowing between the source and load via the network. The parameter can be (1) statistically based, e.g. variance of percent delivered power, or (2) amplitude modulation in one or both of the 2-20 kHz and 50-200 kHz ranges.