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:
Aug. 11, 1981
Filed:
May. 02, 1979
Friedrich W Thomas, Hasselroth, DE;
Konrad Priess, Hahl am Main, DE;
Leybold-Heraeus, Cologne, DE;
Abstract
The invention relates to a method and a circuit for the regulation of the discharge process in a cathode sputtering apparatus equipped with current, voltage and pressure regulators for controlling the sputtering process. A temperature rise in the discharge area in the course of operation is unavoidable, and, if constant pressure were maintained, this would result in a reduction of the charge carrier density and hence in a reduction of the discharge current, resulting simultaneously in a change in the rate of deposition. The invention resides in regulating to a programmed or constant value, not the pressure but the discharge current, doing so by varying the pressure within certain limits. For this purpose, while the sputtering voltage is maintained constant, a current reference level is given with which the actual current of the discharge is compared. Any current deviations are used for the purpose of operating the pressure regulator such that the current is maintained constant in the discharge area. This can be accomplished in an especially simple manner by operating the metering valve for the feeding of the sputtering gas in a current-related manner.