Leybold-heraeus Gmbh

Konrad Priess

Friedrich W Thomas

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.

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Munich, Georgia

Konrad Priess