Patent ID: 8470713

Claim:
An etch method comprising: providing a substrate comprising a first region having a first plurality of gate structures and a second region having a second plurality of gate structures and at least one oxide containing material, wherein the at least one oxide containing material is not present in the first region of the substrate, the first plurality of gate structures in the first region being present in a greater density than the second plurality of gate structures in the second region of the substrate; depositing a layer of a nitride containing material over the first region and the second region of the substrate, wherein the layer of the nitride containing material is deposited having a first thickness over the first region that is less than a second thickness of the layer of the nitride containing material that is present in the second region of the substrate; forming openings through the layer of the nitride containing material to expose a portion of the at least one oxide containing material; and forming dielectric spacers from a remaining portion of the layer of the nitride containing material on the first plurality of gate structures and the second plurality of gate structures with a plasma etch, wherein the at least one oxide containing material introduces oxygen to in the plasma etch to increase etch rate of the nitride containing material to accelerate etching in the second region of the substrate to compensate for a difference in thickness of the first thickness of the layer of nitride containing material over the first region of the substrate and the second thickness of the layer of the nitride containing material over the second region of the substrate, so that the width of the dielectric spacers in the first region of the substrate is substantially equal to the width of the dielectric spacers in the second region of the substrate.