MANUFACTURE OF SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To suppress degradation in the characteristic of a transistor having a thin gate oxide film when transistors having a variety of gate oxide film thicknesses are formed in a single semiconductor device. SOLUTION: The method comprises the steps of: forming a silicon oxide film 8 by a CVD method on a silicon substrate 1 wherein a device isolation region for dividing a first region from a second region is formed by a localized oxidation method; removing the film 8 formed on the first region by the CVD method; and thermally oxidizing the substrate 1 to form a first silicon oxide film 10 on the first region and form second silicon oxide films 8 and 10 thicker than the film 10 on the second region.