Patent ID: 8089026
Filing Date: 2012-01-03
Classification: B23K,H01J

Abstract:
1. A method for DC-plasma processing comprising: supplying power to a plasma vessel with a power supply, to ignite a plasma in the plasma vessel; measuring current across a resonant circuit that is in electrical communication with an output of the power supply; measuring voltage across the resonant circuit; detecting that a plasma arc is imminent prior to arc initiation by determining that a linear voltage drop has occurred over a time duration for which current is substantially constant based on the measured current and measured voltage; and controlling a switch in parallel with the output of the power supply to shunt current away from the plasma prior to arc initiation to increase energy stored in the resonant circuit to extinguish the plasma in response to conditions leading to an arc, and controlling the switch to direct the energy stored in the resonant circuit to the input of the power supply when the conditions leading to an arc are stopped, wherein energy stored in the resonant circuit from shunting current away from the plasma can reignite the plasma after the plasma is extinguished.