Patent ID: 7196896

Claim:
Apparatus for facilitating dechucking a workpiece from an electrostatic chuck in a vacuum plasma processor including a vacuum plasma processor chamber, the processor chamber including an electrostatic chuck for chucking the workpiece, the chuck including an electrode responsive to a DC chucking voltage source, the DC chucking voltage source being arranged to derive a chucking voltage having a value for producing a chucking force to hold the workpiece on the chuck, the apparatus comprising a monitor for monitoring electric current flowing in the chuck as the workpiece is being removed from the chuck, a controller for controlling the DC voltage applied to the electrode, the controller being arranged for (a) reversing the voltage applied to the electrode as processing of the workpiece is being completed and (b) controlling the reverse voltage applied to the chuck in response to the monitored current for at least one workpiece processed subsequently to the workpiece which resulted in the current being monitored.