Patent ID: 8471326

Claim:
A semiconductor memory device comprising: a semiconductor substrate in which a cell region and a peripheral circuit region are provided; a first dielectric film that is formed on the semiconductor substrate in the cell region and the peripheral circuit region; a first conductive film that is formed on the first dielectric film in the cell region and the peripheral circuit region; a first inter-conductive-film dielectric film that is formed on the first conductive film in the cell region; a second inter-conductive-film dielectric film that is formed on the first conductive film in the peripheral circuit region and whose film thickness is larger than the first inter-conductive-film dielectric film; and a second conductive film that is formed on the first inter-conductive-film dielectric film in the cell region and the second inter-conductive-film dielectric film in the peripheral circuit region, wherein the second inter-conductive-film dielectric film includes the first inter-conductive-film dielectric film and a third inter-conductive-film dielectric film below the first inter-conductive-film dielectric film, and wherein the third inter-conductive-film dielectric film is a silicon oxide and wherein the first inter-conductive-film dielectric film includes a nitride film that is in contact with the first conductive film, and the second inter-conductive-film dielectric film includes an oxide film or an oxynitride film in which a composition ratio of oxygen to nitrogen is larger than the nitride film and which is in contact with the first conductive film.