Patent ID: 7813103

Claim:
A reactor for processing a workpiece, comprising: a vacuum chamber including an RF grounded chamber wall; an electrostatic chuck provided in said chamber and comprising: (a) a cathode electrode insulated from ground and a chucking electrode overlying and insulated from said cathode electrode; (b) a dielectric layer overlying said chucking electrode, said dielectric layer having a top surface for supporting a workpiece to be processed; and (c) a lift pin apparatus; a D.C. chucking voltage supply coupled to said chucking electrode and an RF impedance match and an RF power generator coupled through said RF impedance match to said cathode electrode; a voltage sensing apparatus coupled to said chucking electrode and to said cathode electrode; and a controller programmed to enable said lift pin apparatus whenever said voltage sensing apparatus detects equal voltages simultaneously on said chucking and cathode electrodes.