Self-planarized gapfilling for shallow trench isolation

摘要

A new method is disclosed to form a shallow trench isolation with a ozone-TEOS as a gapfilling material. The formation of the shallow trench isolation described herein includes a pad layer, a silicon nitride layer formed on a semiconductor substrate. A thermal oxide layer is subsequently formed on the silicon nitride layer. Then a shallow trench is created via photolithography and dry etching steps to etch the thermal oxide layer, the silicon nitride layer and the pad layer. After photoresist is removed, an ozone-TEOS layer is form in the shallow trench and on the top of the thermal oxide layer for the purpose of isolation. A CMP is perform to make the surface of the substrate with a planar surface. Then, a thermal annealing is used for densification of the ozone-TEOS layer and for forming a lining oxide to provide better isolation.