Patent ID: 6322634
Filing Date: 2001-11-27
Classification: H01L

Abstract:
A precursor to a semiconductor device structure including a shallow trench isolation structure having a substantially flat surface and an integral ledge which extends laterally outward from a trench formed in a semiconductor device layered structure including a semiconductor substrate so as to contact only an area of an active surface of the semiconductor substrate adjacent the trench, the precursor including a buffer film layer over the semiconductor substrate, the precursor formed by the method comprising:disposing a first oxide layer on the active surface of the semiconductor substrate;disposing the buffer film layer of substantially oxidation resistant and selectively etchable material on said first oxide layer;exposing at least one portion of said active surface through the buffer film layer and through said first oxide layer;removing at least one portion of the semiconductor substrate to form the trench;forming a second oxide layer on exposed portions of said semiconductor substrate within the trench;selectively etching a portion of the buffer film layer to expose at least one trench edge at a juncture of the trench and the active surface of the semiconductor substrate;applying a layer of isolation material over the buffer film layer to fill the trench;removing a portion of said layer of isolation material above the buffer film layer; anddensifying the isolation material.