Patent Number: 6,333,232

Title: Semiconductor device and method of manufacturing the same

Abstract: Before forming a trench in a silicon substrate through a patterned siliconnitride film serving as a mask, etching is executed until the main surfaceof the silicon substrate is exposed. Thereafter exposed side walls of asilicon dioxide film and a polysilicon film and the exposed surface of thesilicon substrate are oxynitrided thereby forming an silicon oxynitridefilm. Thereafter the trench is formed, then a silicon dioxide film isformed on its inner wall, and thereafter the trench is filled with aninsulation. In the process of forming the silicon dioxide film on theinner wall, a bird's beak is formed on the side walls of the silicondioxide film and the polysilicon film. The silicon oxynitride filmsuppresses excessive growth of the bird's beak and prevents the bird'sbeak from formation of a depressed part. Thus, reduction of the area of anactive region caused by the bird's beak is suppressed without nodepression part formed on the upper end of an STI structure.

Inventors: Kunikiyo; Tatsuya (Tokyo, JP)

Assignee:

International Classification: H01L 21/762 (20060101); H01L 21/70 (20060101); H01L 021/336 (); H01L 021/76 ()

Expiration Date: 12/25/2014