Patent ID: 6221785
Filing Date: 2001-04-24
Classification: H01L

Abstract:
A method for forming shallow trench isolations, comprising the steps of:defining a wafer substrate;forming a first insulating layer on said substrate;depositing a second insulating layer on said first insulating layer, said first insulating layer being a different material than said second insulating layer;forming at least one trench in said substrate through said first and second insulating layers;depositing a third insulating layer over said second insulating layer and in said trench, said third insulating layer being the same material as said first insulating layer;removing portions of said third insulating layer deposited over said second insulating layer to obtain a planar surface on said second insulating layer;anisotropically etching said third insulating layer such that said third insulating layer inside said trench has sidewalls contiguous with said second insulating layer;isotropically etching to remove said sidewalls such that said third insulating layer in said trench is planar with said first insulating layer; andremoving said second insulating layer.