Patent ID: 6984288

Claim:
A vacuum plasma chamber for processing a workpiece, the chamber including: a first electrode for electrical coupling with gas in the chamber and for connection to a first relatively high frequency RF source, a second electrode for carrying the workpiece and electrical coupling with gas in the chamber and for connection to a second relatively low frequency RF source, an exterior wall at a reference potential, and a plasma excitation region for confining the plasma, the region being spaced from the exterior wall, wherein the plasma excitation region including (a) louvers spaced from the wall, the plasma excitation region being arranged so that the gas flows into the plasma excitation region through the first electrode and out of the plasma excitation region between the louvers, and (b) first and second surfaces at the reference potential, the first surface being located between the louvers and the electrode for carrying the workpiece, the second surface being located between the louvers and the first electrode.