Method of fabricating a shallow trench isolation structure

摘要

A method of fabricating a well-filled STI Structure in a semiconductor substrate. A trench is formed in the semiconductor substrate. A liner oxide and a liner nitride are formed on the bottom and sidewall of the trench subsequently. A HDP oxide layer is deposited in the trench conformally to fill a portion of the trench. A layer of poly-silicon is deposited over the HDP oxide layer conformally. The semiconductor substrate is subjected to a thermal treatment to oxidize the poly-silicon. The surface of the semiconductor substrate is planarized to form a shallow trench isolation structure. The trench is well filled by the oxidized poly-silicon and the HDP oxide without voids and seams.