Patent ID: 6191003
Filing Date: 2001-02-20
Classification: H01L

Abstract:
A method for planarizing a polycrystalline silicon layer deposited on a trench, which is formed on a semiconductor substrate, comprising the following steps:depositing a polycrystalline silicon layer on the surface of said semiconductor substrate to overfill said trench, wherein at least one dimple is formed on said polycrystalline silicon layer;forming an oxide layer on said polycrystalline silicon layer, wherein said oxide layer has an enough thickness so as to overfill said at least one dimple;partially oxidizing said polycrystalline silicon layer in such a way that the upper portion of said polycrystalline silicon layer is transformed into a polysilicon oxide layer whose bottom surface is higher than the opening of said trench and substantially planar; andremoving said oxide layer and said polysilicon oxide layer to expose a non-oxidized portion of said polycrystalline silicon layer.