PURPOSE: To prevent the generation of protrusions of a capacitor insulating film in a contact hole, and eliminate the disconnection of an aluminum wiring for a bit line, by transforming the capacitor insulating film exposed on the inner wall surface of the contact hole into an oxide film by implanting oxygen ions.

CONSTITUTION: After a cell plate 92 having a desired pattern is formed on a capacitor insulating film 8 composed of a nitride film formed on a first layer insulating film 6, an SiO2 film of practically uniform thickness is formed on the whole surfaces of the capacitor insulating film 8 and the cell plate 92 is formed by, e.g. CVD method. Oxygen ions 16 are implanted through the SiO2 film, and the part of the capacitor insulating film 8 which is not covered with the cell plate 92 is exchanged for an insulating film 84; a second layer insulating film 83 is formed by forming further an insulating film on the wafer whole surface; a contact hole 11 is formed so as to penetrate the first and the second layer insulating films and reach a silicon substrate 1; an aluminum wiring 14 for a bit line is formed in the contact hole and on the second interlayer insulating film.