Patent ID: 8771536

Claim:
A method of etching a patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has an exposed silicon-and-carbon-containing region and an exposed silicon oxide region, the method comprising: flowing each of a fluorine-containing precursor and an oxygen-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the plasma region to produce plasma effluents; flowing the plasma effluents through an ion suppression element configured to suppress the migration of ionically-charged species out of the remote plasma region; and etching the exposed silicon-and-carbon-containing region by flowing the plasma effluents into the substrate processing region through through-holes in a showerhead, wherein the selectivity of the etching operation (silicon-and-carbon-containing region:silicon oxide region) is greater than or about 100:1.