Patent ID: 7767511

Claim:
A method of manufacturing a semiconductor device, comprising: forming an NMOS gate structure and a PMOS gate structure over a semiconductor substrate, the NMOS and PMOS gate structures including respective patterned NMOS and PMOS polysilicon gate electrodes, and the semiconductor substrate including respective NMOS and PMOS source/drain regions adjacent the NMOS and PMOS gate structures; forming a protective layer over the NMOS and PMOS source/drain regions and over the NMOS and PMOS gate structures; forming a chemical/mechanical polishing (CMP) layer over the protective layer, over the NMOS and PMOS source/drain regions and over the NMOS and PMOS gate structures; using chemical/mechanical polishing, removing a portion of the CMP layer down to a portion of the protective layer over the NMOS and PMOS gate structures; etching the portion of the protective layer over the NMOS and PMOS gate structures to expose portions of the NMOS and PMOS gate electrodes, leaving remaining portions of the CMP layer and the protective layer over the NMOS and PMOS source/drain regions and over other portions of the NMOS and PMOS gate electrodes; following the etching, forming and patterning a first mask over the remaining portions of the CMP layer and the protective layer to leave exposed the exposed portion of one of the NMOS and PMOS gate electrodes, and to cover the exposed portion of the other of the other of the NMOS and PMOS gate electrodes; in a first implant through the patterned first mask, doping the exposed portion of the one of the NMOS and PMOS gate electrodes; following the first implant, forming and patterning a second mask over the remaining portions of the CMP layer and the protective layer to leave exposed the exposed portion of the other of the NMOS and PMOS gate electrodes, and to cover the exposed portion of the one of the NMOS and PMOS gate electrodes; and in a second implant through the patterned second mask, doping the exposed portion of the other of the NMOS and PMOS gate electrodes.