Patent ID: 8119489
Filing Date: 2012-02-21
Classification: H01L

Abstract:
1. A method of forming a shallow trench isolation (STI) structure, the method comprising: providing a substrate; forming a masking layer over the substrate; patterning the masking layer; forming a plurality of trenches in the substrate; forming an insulation layer over the substrate to fill the plurality of trenches in the substrate; performing a first planarization process to the insulation layer until a surface of the masking layer is exposed; after performing the first planarization process performing an etching back process to the planarized insulation layer, so that a surface of the planarized insulation layer is lower than a surface of the masking layer but higher than a substrate surface; forming a polysilicon layer over the substrate to cover the patterned masking layer and the insulation layer; after forming the polysilicon layer performing a second planarization process to the polysilicon layer until the surface of the patterned masking layer is exposed for forming a polysilicon cap so that the polysilicon cap is disposed to cover a whole surface of the insulation layer in each of the plurality of trenches; and removing the patterned masking layer.