Patent ID: 6368941
Filing Date: 2002-04-09
Classification: H01L

Abstract:
A method of fabricating an STI, the method comprising:providing a silicon substrate; for lifting a patterned hardmask on the silicon substrate, wherein the patterned hard mask is a laminated layer comprising a pad oxide and a silicon nitride layer, and exposes a portion of the surface of the silicon substrate; etching the exposed surface of the silicon substrate not covered by the hardmask to form a trench in the silicon substrate; wet etching a portion of the pad oxide layer around the STI edge to expose a portion of the top surface of the silicon substrate located beneath the silicon nitride layer surrounding the periphery of the trench; synchronously oxidizing both the interior surface of the trench and the exposed portion of the top surface of the silicon substrate surrounding the periphery of the trench by a high-density oxygen plasma oxidation process at both a low temperature and a low pressure, to form a liner oxide layer having a first thickness on the interior surface of the trench and a thicker oxide layer having a second thickness, greater than the first thickness, on the STI edge; and filling in the trench by a dielectric layer; wherein an electrical field is applied to the oxygen plasma so that ions created by the plasma has a low ion bombardment energy; wherein the high-density oxygen plasma oxidation process is independent of the surface orientation of silicon.