Patent ID: 6682985
Filing Date: 2004-01-27
Classification: H01L

Abstract:
A method of manufacturing a semiconductor device comprising the steps of:forming a multilayer film, which includes a silicon oxide layer, a polycrystalline silicon layer having a thickness, above the silicon oxide layer and a silicon nitride layer having a first thickness, above the polycrystalline silicon layer, on a main surface of a silicon substrate; patterning said multilayer film and etching a trench for element separation in said silicon substrate; forming an inner wall silicon oxide film at a thickness which covers inner walls of said trench by oxidizing the inner wall surfaces which include sidewalls of said multilayer film; forming a trench oxide layer so as to fill in the trench which is covered with said inner wall silicon oxide film and so as to contact a top surface of said silicon nitride layer; polishing said trench oxide layer and said silicon nitride layer through CMP polishing reducing the first thickness of said silicon nitride layer to a second thickness leaving an upper surface of the silicon nitride layer exposed and forming a recess in the trench oxide layer such that an upper surface of the trench oxide is below the upper surface of the silicon nitride layer; etching the trench oxide layer after, CMP polishing to reduce the height by an amount no greater than the thickness of said inner wall silicon oxide film for the purpose of height adjustment of a trench separation band.