Patent ID: 6074932
Filing Date: 2000-06-13
Classification: H01L

Abstract:
A method of forming a trench region in a semiconductor substrate, said method comprising the steps of:forming a first pad layer over said semiconductor substrate;forming a stacked layer over said first pad layer;defining an opening to said semiconductor substrate in said first pad layer and said stacked layer;removing a portion of said first pad layer to have an undercut region under said stacked layer around said opening;forming a second pad layer on an exposed portion of said semiconductor substrate under said opening and said undercut region;forming a buffer layer within said undercut region and a sidewall structure on said stacked layer;removing a portion of said second pad layer uncovered by said sidewall structure;removing a portion of said semiconductor substrate uncovered by said stacked layer and said second pad layer to form a trench; andforming a first insulator layer over said trench and within said undercut region.