Patent ID: 6251746
Filing Date: 2001-06-26
Classification: H01L

Abstract:
A method of forming a trench isolation region, comprising the steps of:forming a trench masking layer comprising a first material, on a semiconductor substrate;etching a trench in the semiconductor substrate, using the trench masking layer as etching mask;forming a trench oxide layer on a sidewall of the trench and on a sidewall of the trench masking layer; thenforming a trench nitride layer comprising a second material different from the first material on the trench oxide layer so that the trench nitride layer extends opposite the sidewall of the trench and opposite the sidewall of the trench masking layer; thenfilling the trench with a trench insulating material;removing the trench masking layer to expose an outer sidewall of the trench oxide layer, by selectively etching the trench masking layer with an etchant that selectively etches the first material at a higher rate than the second material; andetching back the trench insulating material, the trench oxide layer and the trench nitride layer, to define the trench isolation region.