Cushman Darby & Cushman IP Group of Pillsbury Madison & Sutro LLP
Semiconductor physical-quantity sensor and method for manufacturing same
 A polysilicon thin film is formed on a silicon substrate by LPCVD technique. At this time, by a performing film formation at a low temperature of approximately 620.degree. C., for example, an irregularities portion is formed on the surface thereof. A silicon oxide film that serves as a sacrificial layer is formed thereon and, on this sacrificial layer, a polysilicon thin film that serves as a movable portion forming thin film is formed. Then, the silicon oxide film beneath this polysilicon thin film is removed by wet etching to thereby form a movable portion. As a result, the movable portion of a beam structure that is composed of the thin film is disposed over the silicon substrate at a prescribed distance therefrom. Although an etchant-replacing liquid enters between the movable portion and the substrate whereby the movable portion is attracted toward the substrate, the movable portion is prevented from adhering to the substrate by means of the irregularities portion. 
Nippondenso Co., Ltd.
G G G B
G01P G01P G01P B81B
inventional additional inventional inventional
Yukihiro Yoshitaka Makiko
Takeuchi Gotoh Fujita