Assembly for feeding in HF current for tubular cathodes

摘要

An arrangement is provided for feeding in HF current for rotatable tubular cathodes in a vacuum chamber of a plasma coating system as well as a high frequency current source. Located inside the tubular cathode is a magnet arrangement that extends along said tubular cathode for generating a magnetic field. The arrangement enables a low loss infeed of HF current, so that a particularly homogeneous sputter removal from the tubular cathode is guaranteed. The HF current source is coupled to the tubular cathode inside the vacuum chamber by a capacitive infeed of HF current in the form of a coupling capacitor. The coupling capacitor includes a part of the surface of the tubular cathode and a metal plate or metal film that surrounds the tubular cathode, at least partially, at a specified distance.

主权项

1. An arrangement for feeding in HF current for a rotatable tubular cathode serving as a sputtering target in a vacuum chamber of a plasma coating system, the rotatable tubular target comprising a support tube supporting a target shell, the target shell comprising target material to be removed during sputtering and deposited on a substrate, in combination with a high frequency current source and a matching network and, located inside said tubular cathode, a stationary magnet arrangement that extends along said tubular cathode, wherein the HF current source is coupled via the matching network to the tubular cathode inside the vacuum chamber by a coupling capacitor, the coupling capacitor consisting of a part of a surface of the tubular cathode and a metal plate or metal film surrounding approximately half of the rotatable tubular cathode at a specified distance from said surface, wherein the metal plate or metal film extends substantially over an entire free length of the tubular cathode inside the vacuum chamber, and wherein the metal plate or metal film is located diametrically opposite the stationary magnet arrangement so as not to impede sputtering of the target material of the target shell, and wherein the coupling capacitor serves as a capacitor of the matching network or the coupling capacitor replaces a capacitor of the matching network at the same time as serving as a capacitive infeed of HF current to the rotatable tubular cathode, and wherein the specified distance is readjusted during sputtering as a function of decreasing diameter of the tubular cathode due to removal of target material from the target shell.