Abstract: We have developed a gas distribution showerhead assembly, for use in a semiconductor processing chamber, which can be easily cleaned, with minimal chamber downtime. The gas distribution showerhead assembly includes an electrode having openings therethrough, and a gas distribution plate which includes a plurality of through-holes for delivering processing gases into the semiconductor processing chamber. The gas distribution plate is bonded to a first, lower major surface of the electrode. A removable insert which fits into an opening in the electrode through which gas flows. Spacing between surfaces of the removable insert and surfaces of the electrode is adequate to permit gas flow, but inadequate for plasma ignition within the opening. The removable insert can be easily removed during cleaning of the gas distribution showerhead, permitting the holes in the gas distribution plate to be easily accessed from both sides of the gas distribution plate.