Method for manufacturing semiconductor device

摘要

A method for manufacturing a semiconductor device enables the formation of a well optimized for a fine MOS transistor and a well formed deep with a relatively low concentration for a high voltage MOS transistor without increasing the number of manufacturing steps. The method for manufacturing a semiconductor device includes the steps of: forming a first ion implantation expendable film and an etching mask film on a first conductive type semiconductor substrate; patterning the etching mask film into a shape of an active and field region; introducing dopant into the substrate; forming a trench groove on the substrate; forming an insulation film in the trench groove; forming a first well; flattening the insulation film; removing the etching mask film; removing the expendable film; forming a second ion implantation expendable film on the substrate; forming a mask pattern; and forming a second well by introducing dopant into the substrate.