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:
Apr. 07, 1998
Filed:
Oct. 17, 1996
Richard Raymond Mett, Santa Clara, CA (US);
Mahmoud Dahimene, Sunnyvale, CA (US);
Paul E Luscher, Sunnyvale, CA (US);
Siamak Salimian, Sunnyvale, CA (US);
Mark Steven Contreras, Sunnyvale, CA (US);
Applied Materials, Inc., Santa Clara, CA (US);
Abstract
A method and apparatus for actively controlling the DC cathode potential of a wafer support pedestal within a semiconductor wafer processing system. The apparatus contains a variable DC power supply coupled through an RF filter to a cathode pedestal. The variable DC power supply is actively controlled by a control signal generated by a cathode bias control unit, e.g., a computer or other control circuitry. The cathode bias control unit can be as simple as an operator adjustable control signal, e.g., a rheostat. However, for more accurate control of the DC power supply, a feedback circuit is used that generates a control signal that is proportional to the peak-to-peak voltage on a cathode pedestal. The application of the DC bias to the pedestal reduces the DC potential difference between the wafer and the cathode and, thereby avoids arcing from the wafer to the pedestal.