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

A method for operating a substrate processing system to etch a substrate arranged on a substrate support, comprising:

• providing a first chamber above a second chamber, wherein the second chamber includes a substrate support and wherein a dual gas plenum is arranged between the first chamber and the second chamber;
• supplying an inert gas species selected from a group consisting of helium, argon, neon, krypton, and xenon to the first chamber;
• generating plasma including a metastable species in the first chamber, wherein an upper surface of the dual gas plenum is directly exposed to the plasma;
• supplying a reactive gas species selected from a group consisting of molecular oxygen, molecular nitrogen, molecular hydrogen, nitrogen trifluoride, and carbon tetrafluoride to the dual gas plenum;
• and
• separately distributing and delivering the metastable species and the reactive gas species to the second chamber to etch the substrate.