Patent ID: 8791001

Claim:
A method for making metal gate stacks of a semiconductor device comprising: forming a first metal layer on a substrate; forming a conductive material layer on the first metal layer; forming a patterned photoresist layer on the conductive material layer, the patterned photoresist layer defining openings to expose the conductive material layer; applying a first etching process to the conductive material layer to remove the conductive material layer within the openings of the patterned photoresist layer to expose the first metal layer within the openings of the patterned photoresist layer; applying a second etching process to the first metal layer to remove the first metal layer within the openings of the patterned photoresist layer resulting in a first metal gate, the second etching process being different than the first etching process, wherein applying the second etching process includes implementing a fluorine-containing plasma to remove the first metal layer within the openings of the patterned photoresist layer; applying a nitrogen-containing plasma to the substrate to remove the patterned photoresist layer; and thereafter removing the first metal layer and conductive layer from the first metal gate.