Method and manufacturing a device separation film in a semiconductor device

Abstract

A method of manufacturing a device separation film in a semiconductor device is disclosed. In a process technology in which a trench is formed in a silicon substrate, silicon is grown at the bottom of the trench by SEG method in order to lower the aspect ratio and the trench is then filled with an insulating material so that voids are not generated. In order for silicon to be normally grown, a thermal oxide film formed at the bottom of the trench must be removed without removing the oxide film from the sides of the trench. The disclosed method reduces the speed of forming a thermal oxide film at the bottom of the trench, by plasma process using CF4 and O2 gas after forming the trench. Thereby facilitating the removal of the thermal oxide film at the bottom of the trench while minimizing loss of the thermal oxide film at the sidewall of the trench.

Dependencies are inferred from the claim text.