Fujitsu Corporation

Masaki Ishidao

Masahiro Kobayashi

Masatoshi Fukuda

A polysilicon film and the like are patterned to form ndiffusion layers on a silicon substrate. Subsequently, an outer edge of an AlOfilm is made retreat to be smaller than that of a gate electrode by performing isotropic etching of the AlOfilm, using a solution of sulfuric acid with hydrogen peroxide. A silicon oxide film, a silicon nitride film, the polysilicon film and the like are hardly removed although the solution of sulfuric acid with hydrogen peroxide exhibits higher etching rate to the AlOfilm, enabling almost exclusive etching of the AlOfilm at a high selectivity ratio. Subsequently, another polysilicon film is formed so as to fill spaces formed after the retreat of the AlOfilm under the silicon oxide film. Subsequently, a sidewall insulating film is formed by remaining portions of the later polysilicon film in the spaces by performing RIE, oxidation, or the like of the later polysilicon film.

Growing community of inventors

Atsugi, Japan

Masaki Ishidao