Patent ID: 7838962

Claim:
A method for manufacturing a semiconductor device comprising: forming a capacitor, a transistor and a diffusion resistor in a p-type silicon substrate having a (111)-plane orientation and an off-set angle in a range between 3 degrees and 4 degrees; forming a junction separation layer for separating each of the capacitor, the transistor and the diffusion resistor in the substrate; forming a thermal oxide film over the substrate; forming a first opening in the thermal oxide film to expose the substrate; forming a CVD oxide film over the thermal oxide film and the exposed substrate; forming a second opening corresponding to the first opening in the CVD oxide film to expose the substrate; forming a first silicon oxide film by thermal oxidation over the exposed portion of the substrate via the second opening; forming a first silicon nitride film by low pressure CVD over the CVD oxide film, the first silicon oxide film and a sidewall of the second opening, and over the junction separation layer via the thermal oxide film and the CVD oxide film; removing a portion of the first silicon nitride film in the second opening to expose the first silicon oxide film; forming a third opening in the first silicon nitride film to expose the CVD oxide film over the junction separation layer together with the removing the portion of the first silicon nitride film; forming a second silicon oxide film by low pressure CVD over the exposed portion of the first silicon oxide film, the first silicon nitride film and in the third opening; etching a region of the first silicon oxide film and the second silicon oxide film, the region in which the first silicon oxide film and the second silicon oxide film are directly contacted, so that a contact hole to reach the substrate is formed; forming a wiring including aluminum in the contact hole; and forming a second silicon nitride film by plasma CVD as a protecting film over the wiring, wherein a thickness of each of the first silicon oxide film, the first silicon nitride film and the second silicon oxide film is smaller than a thickness of each of the thermal oxide film and the CVD oxide film.