MANUFACTURE OF SEMICONDUCTOR DEVICE

PURPOSE:To enable a pattern to be sharply lessened in dimensional error so as to obtain a polycrystalline silicon gate element of high accuracy by a method wherein a thin silicon oxide film formed at a low temperature is used as an etching mask. CONSTITUTION:In a method of manufacturing a semiconductor device, where an amorphous silicon film 53 is deposited on a substrate 51 and then selectively etched using a mask pattern formed on the film 52, and the substrate 51 is thermally treated to turn the amorphous silicon film 53 polycrystalline, a thin silicon oxide film 54 which is formed at a low temperature at which an amorphous silicon film is not turned polycrystalline is used as the mask pattern formed on the amorphous silicon film 53.