Fabrication of replacement metal gate devices

摘要

Methods for polishing multiple dielectric layers to form replacement metal gate structures include a first chemical mechanical polish step to remove overburden and planarize a top layer to leave a planarized thickness over a gate structure. A second chemical mechanical polish step includes removal of the thickness to expose an underlying covered surface of a dielectric of the gate structure with a slurry configured to polish the top layer and the underlying covered surface substantially equally to accomplish a planar topography. A third chemical mechanical polish step is employed to remove the dielectric of the gate structure and expose a gate conductor.