RF plasma reactor with cleaning electrode for cleaning during processing of semiconductor wafers

The invention is carried out in a plasma reactor for processing a semiconductor wafer, the plasma reactor having a chamber for containing a processing gas and having a conductor connected to an RF power source for coupling RF power into the reactor chamber to generate from the processing gas a plasma inside the chamber, the chamber containing at least one surface exposed toward the plasma and susceptible to contamination by particles produced during processing of the wafer, the invention being carried out by promoting, during processing of the wafer, bombarding of particles from the plasma onto the one surface to remove therefrom contaminants deposited during processing of the wafer. Such promoting of bombarding is carried out by providing an RF power supply and coupling, during processing of the wafer, RF power from the supply to the one surface. The coupling may be performed by a capacitive cleaning electrode adjacent the one surface, the capacitive cleaning electrode connected to the RF power supply. The capacitive cleaning electrode preferably is disposed on a side of the one surface opposite the plasma so as to be protected from contact with the plasma. Alternatively, the coupling may be carried out by a direct electrical connection from the RF power supply to the one surface.