PURPOSE: To enable manufacture at a low cost with high accuracy in the thickness dimension of a diaphragm by letting an epitaxial growth layer grow on the surface of an SOI wafer, and performing selective polishing with a silicon oxide film, formed thereon, as a stopper.
CONSTITUTION: Etching is applied to silicon and silicon oxide 203 at the required places of an SOI wafer 201, and an epitaxial growth layer 205 is let grow on the surface. A silicon oxide film 206 is then formed on the surface, and after etching the required place, epitaxial growth 207 of the specified thickness is let grow. After performing selective polishing with the silicon oxide film 206 as a stopper, the silicon oxide film 206 is removed by etching, and a recessed part 208 is formed on the surface of the growth layer 205 by etching or selective oxidation. A hole for etching the silicon oxide 203 is formed at the growth layer 205 by etching, and then the silicon oxide 203 is etched by hydrogen fluoride. Lastly, the wafer 201 is anode-jointed to a supporting board.
NAGAI KOJI
TSUKAMOTO HIDEO
