PURPOSE: To etch the first polycrystalline silicon film at the drive element region of a semiconductor storage device without etching a semiconductor substrate by not eliminating a third silicon oxide film of the drive element of the semiconductor storage device until the etching process of a first polycrystalline silicon film.

CONSTITUTION: A third silicon oxide film 103 of the drive element of a semiconductor storage device is not eliminated until the etching process of a first polycrystalline silicon film 106 at a region to serve as the drive element of the semiconductor storage device, thus etching the first polycrystalline silicon film 106 of the drive element region of the semiconductor storage device without etching a semiconductor substrate 101. Therefore, the third silicon oxide film 103 of the region to serve as the drive element of the semiconductor device is eliminated by the photoetching method, thus manufacturing the drive element of the semiconductor storage device successively.