Patent ID: 7319073

Claim:
A method of reducing silicon damage around laser marking region of wafers in shallow trench isolation (STI) chemical mechanical polishing (CMP) process, comprising: providing a wafer having thereon a plurality of integrated circuit die areas, scribe line that surrounding each of the integrated circuit die areas, and a laser marking region having therein a laser marking feature, wherein the laser marking region is disposed at wafer edge and is adjacent to the scribe line; forming a pad oxide layer on the wafer; forming a pad nitride layer on the pad oxide layer; forming an active area (AA) photoresist pattern on the pad nitride layer, the AA photoresist pattern comprises trench openings that expose STI trench areas within the integrated circuit die areas to be etched into a substrate of the wafer, and dummy openings that merely expose a transitioning region of the laser-marking region; using the AA photoresist pattern as etching hard mask, etching the pad nitride layer, the pad oxide layer and the substrate through the trench openings and dummy openings, so as to form STI trenches within the integrated circuit die areas and dummy trenches in the transitioning region of the laser-marking region; removing the AA photoresist pattern; depositing a trench fill dielectric over the wafer the trench fill dielectric filling the STI trenches and the dummy trenches; forming a reverse mask having an opening exposing the laser-marking region except the transitioning region; etching the trench fill dielectric though the opening of the reverse mask to reduce thickness of the trench fill dielectric above the laser marking feature; removing the reverse mask; and using the pad nitride layer as a polish stop layer, chemical mechanical polishing the trench fill dielectric.