A bias sputter coating apparatus is provided with a cathode target assembly having a central electrode which is maintainable at an adjustable voltage level which is negative with respect to the chamber anode but positive with respect to the cathode voltage and the bias voltage on the substrate. The apparatus...http://www.google.de/patents/US5080772?utm_source=gb-gplus-sharePatent US5080772 - Method of improving ion flux distribution uniformity on a substrate
