Patent ID: 7157781

Claim:
A method for manufacturing a semiconductor device including a semiconductor substrate and a membrane, wherein a cavity is located between an active surface of the semiconductor substrate and the membrane and hermetically sealed, the method comprising: forming a sacrificial layer at a position where a cavity is to he formed on an active surface of a semiconductor substrate; forming a first film, a part of which is to be a part of a membrane, to cover the sacrificial layer; forming a through hole, which extends through the first film; forming a reflow layer, which is made of a material that becomes viscous when heated, to cover the first film such that the through hole are plugged by the reflow layer; forming an etching hole, which permits the sacrificial layer to be exposed to an outside, such that the etching hole is located at a position corresponding to the through hole; etching the sacrificial layer through the etching hole to form a cavity; and reflowing the reflow layer by heating to form a second film, a part of which is to be a part of the membrane, wherein the etching hole and the through hole are plugged by the second film when the reflow layer is reflowed.