Systems and methods for metastable activated radical selective strip and etch using dual plenum showerhead

A gas distribution device for a substrate processing system, comprising:

• an annular side wall;
• a flange extending radially outwardly from one end of the annular side wall;
• a dual gas plenum extending between and enclosing an opposite end of the annular side wall and including a plasma-exposed side and a substrate-facing side;
• a first gas channel arranged around a periphery of the dual gas plenum;
• a plurality of connecting gas channels extending through the dual gas plenum between opposite sides of the first gas channel;
• a second gas channel extending horizontally from a radially outer surface of the flange into the flange;
• a third gas channel extending vertically through the annular side wall and including:
• a first end in fluid communication with a first end of the second gas channel;
• and
• a second end in fluid communication with the first gas channel;
• a first plurality of through holes extending from the plurality of connecting gas channels through the substrate-facing side of the dual gas plenum;
• and
• a second plurality of through holes extending from the plasma-exposed side of the dual gas plenum to the substrate-facing side of the dual gas plenum.