Patent ID: 7291541

Claim:
A method for manufacturing an isolation trench in a semiconductor device, said method comprising the steps of: providing a substrate for said semiconductor device; etching a trench in said substrate; growing a silicon dioxide liner in said trench; filling said trench with polysilicon material; depositing polysilicon material on top of said filled trench to protect said silicon dioxide liner; etching the deposited polysilicon material so as to leave a portion of the deposited polysilicon material that is over the trench and that extends laterally over at least one edge of the trench, wherein the portion of the deposited polysilicon material comprises a top and a side, the side extending from the top of the portion of the deposited polysilicon material to one of: the silicon dioxide liner and the substrate; and placing a layer of oxidation material over the portion of the deposited polysilicon material during a subsequent oxidation process, wherein the layer of oxidation material contacts the top and the side of the portion of the deposited polysilicon material.