Patent ID: 6821913
Filing Date: 2004-11-23
Classification: H01L

Abstract:
A method of forming dual oxide layers at the bottom of a trench, the method comprising:providing a substrate having a trench which includes a bottom and a sidewall; forming a first oxide layer on the sidewall and the bottom of the trench of the substrate; forming a photoresist layer on the substrate, the photoresist layer filling the trench of the substrate; partially etching back the photoresist layer to leave a remaining photoresist layer in the trench, the height of the remaining photoresist layer being lower than the depth of the trench; performing a curing treatment of the remaining photoresist layer; removing a portion of the first oxide layer to leave a remaining first oxide layer at the bottom of the trench; removing the remaining photoresist layer; and forming a second oxide layer on the substrate covering at least the remaining first oxide layer.