Fabrication of replacement metal gate devices

A method for polishing replacement metal gate structures to planarize oxide layers and expose underlying nitride and polysilicon covered areas, comprising:

• a first chemical mechanical polish step to remove overburden and planarize oxide layers leaving 300 to 600 Å of oxide remaining;
• a second chemical mechanical polish step including removal of the oxide layers and exposing underlying nitride and polysilicon covered surfaces with an oxide:nitride:polysilicon selectivity of about 1:1:1 to about 2:1:1 to provide planar topography;
• a third chemical mechanical polish step to remove the nitride layers and expose the polysilicon layers;
• and
• replacing at least a portion of the polysilicon layer with a metal layer to form the metal gate structure.