Variable reactances in an impedance-matching box for an RF coil, in a plasma deposition system for depositing a film of sputtered target material on a substrate, can be varied during the deposition process so that the RF coil and substrate heating, and the film deposition, are more uniform due to "time-averaging"...http://www.google.com/patents/US6652717?utm_source=gb-gplus-sharePatent US6652717 - Use of variable impedance to control coil sputter distribution
