APPARATUS AND METHODS FOR PLASMA ETCHING

摘要

Apparatus and methods for plasma etching are disclosed. In one embodiment, an apparatus for etching a plurality of features on a wafer comprises a chamber (146), a feature plate (148) disposed in the chamber for holding the wafer, a gas channel (106) configured to receive a plasma source gas, an anode (142) disposed above the feature plate, a cathode (143) disposed below the feature plate, a radio frequency power source (144) configured to provide a radio frequency voltage between the anode and the cathode so as to generate plasma ions from the plasma source gas, and a clamp (250) configured to clamp the wafer against the feature plate. The clamp includes at least one measurement hole (251) for passing a portion of the plasma ions to measure a DC bias of the feature plate.