Patent ID: 7709348

Claim:
A method for manufacturing a semiconductor device, the method comprising: preparing a substrate having a quartz support substrate having a first main surface and a second main surface opposite to the first main surface, and a silicon layer provided over the first main surface; setting to the substrate, a chip forming area including element forming areas and an element isolation area lying outside the element forming areas, and a chip non-forming area lying outside the chip forming area and including a ring-shaped circumferential area set inwardly out of a circumferential end face of the substrate and a peripheral area which surrounds the chip forming area inwardly from the circumferential area; forming a substrate silicon oxide film over the entire upper surface of the silicon layer; forming a silicon nitride film over the entire upper surface of the substrate silicon oxide film by a plasma CVD method; patterning the silicon nitride film to form a mask pattern having a circumferential exposure portion that exposes the substrate silicon oxide film in the circumferential area, a first opening pattern that exposes the substrate silicon oxide film of the element isolation area in the chip forming area, and a second opening pattern that exposes the substrate silicon oxide film within the peripheral area; thermally oxidizing the substrate using the mask pattern as a mask thereby to form an element isolation structure portion in the silicon layer of the element isolation area; and eliminating the mask pattern and the substrate silicon oxide film.