Patent ID: 8313665

Claim:
A method of controlling plasma etching, comprising: supplying process gas to a plasma etching chamber through a showerhead electrode assembly comprising: a showerhead electrode mounted in an interior of the plasma etching chamber and powered by radio frequency (RF) energy; a backing plate attached to the showerhead electrode; a thermal control plate attached to the backing plate via a plurality of fasteners at multiple contact points across the backing plate; and at least one thermally and electrically conductive gasket separating the backing plate and the thermal control plate at the contact points, the process gas flowing into a gap between the showerhead electrode and a bottom electrode on which a semiconductor substrate is supported; and etching a semiconductor substrate in the plasma etching chamber by applying RF power to the showerhead electrode and energizing the process gas into a plasma state, wherein the temperature of the showerhead electrode is controlled by the thermal control plate via enhanced thermal conduction through the at least one thermally and electrically conductive gasket.