SEMICONDUCTOR DEVICE SEPARATED BY TRENCH, AND FORMING METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a forming method of a semiconductor device having a trench element isolation film. SOLUTION: The method includes a step for successively forming a buffer insulating film and a hard mask film on a semiconductor substrate. The hard mask film and buffer insulating film are patterned continuously for forming an opening for exposing a specific region on the semiconductor substrate. The exposed semiconductor substrate is selectively etched for forming a trench, and a lower element separation film having a groove is formed on a sidewall at the upper section in the trench. An upper element isolation film for filling the groove and trench is formed on the lower element separation film, and the hard mask film and buffer insulating film are etched until the semiconductor substrate is exposed for removal. At this time, the groove has a specific depth from the surface of the semiconductor substrate. COPYRIGHT: (C)2004,JPO