High selectivity and residue free process for metal on thin dielectric gate etch application

Abstract

Methods for etching electrodes formed directly on gate dielectrics are provided. In one aspect, an etch process is provided which includes a main etch step, a soft landing step, and an over etch step. In another aspect, a method is described which includes performing a main etch having good etch rate uniformity and good profile uniformity, performing a soft landing step in which a metal/metal barrier interface can be determined, and performing an over etch step to selectively remove the metal barrier without negatively affecting the dielectric. In another aspect, a method is provided which includes a first non-selective etch chemistry for bulk removal of electrode material, a second intermediate selective etch chemistry with end point capability, and then a selective etch chemistry to stop on the gate dielectric.