Patent ID: 7018906

Claim:
A method of chemical-mechanical polishing for forming a shallow trench isolation, wherein a substrate having a plurality of active regions, including a plurality of relatively large active regions and a plurality of relatively small active regions, is provided, comprising: forming a silicon nitride layer on the substrate; forming a plurality of shallow trenches between the active regions; forming an oxide layer over the substrate, so that the shallow trenches are filled therewith, forming a partial reverse active mask on the oxide layer, wherein the partial reverse active mask has an opening at a central part of each relatively large active region, wherein the opening exposes a portion of the oxide layer, and wherein the opening has at least a dummy pattern; removing the oxide layer on the central part of each large active region to expose the silicon nitride layer therewithin; removing the partial reverse active mask; and planarizing the oxide layer to expose the silicon nitride layer.