Production of units with metallic spare gates

A method of polishing a plurality of dielectric layers for the formation of structures with metallic spare gates comprise a first chemical mechanical polishing step to remove excess material and planarizing an uppermost layer so as to leave a planarized thickness over a gate structure. A second chemical mechanical polishing step includes removing the thickness to expose an underlying covered surface of a dielectric of the gate structure with a polishing agent, which is configured for the top layer and polishing the underlying surface covered substantially uniformly to to achieve a flat topography. A third chemical mechanical polishing step is used to remove the dielectric from the gate structure and expose a gate conductor.