FIELD OXIDE FILM FORMING METHOD OF SEMICONDUCTOR DEVICE

摘要

The method of forming field oxide film comprises the steps of : forming a first oxidation-preventing film(3) for preventing the oxidation of a semiconductor substrate(1); etching the first oxidation-preventing film(3) by a selective dry etching process, and forming a first trench(6) by etching the exposed substrate; forming a second oxidation-preventing film(8) on the entire top surface of the wafer; forming a spacer second oxidation-preventing film(8') by anisotropic blanket etching of the second oxidation-preventing film(8), and forming a second trench(6') by overetching the bottom of the first trench(6); forming a field oxide film(9) by thermal oxidation; and removing the first oxidation-preventing film(3) and the spacer second oxidation-preventing film(8').