Systems and methods for suppressing parasitic plasma and reducing within-wafer non-uniformity

摘要

A substrate processing system includes: a processing chamber defining a reaction volume; a showerhead including: a stem portion having one end connected adjacent to an upper surface of the processing chamber; and a base portion connected to an opposite end of the stem portion and extending radially outwardly from the stem portion, where the showerhead is configured to introduce gas into the reaction volume; a plasma generator configured to selectively generate RF plasma in the reaction volume; and a collar arranged around the stem portion of the showerhead between the base portion of the showerhead and the upper surface of the processing chamber. The collar includes one or more holes to supply purge gas from an inner cavity of the collar to between the base portion of the showerhead and the upper surface of the processing chamber.