| 摘要 |
PURPOSE: To increase breakdown pressure of a rear diaphragm, by forming a diaphragm adjacent to a second surface, by anisotropically etching a cavity into a substrate, from a first surface side of the substrate having the first and the second surfaces which face each other. CONSTITUTION: A substrate 12 having a first surface and a second surface which face each other is formed. A diaphragm 16 adjacent to the second surface is formed by anisotropically etching a cavity 14 into the substrate 12 from the first surface side. By isotropically etching the cavity 14, the breakdown pressure of the diaphragm 16 to a pressure which is to be applied to the first surface is increased. That is, the diaphragm 16 which has been anisotropically etched is further isotropically thinned. Thereby the rear (cavity side) diaphragm breakdown pressure can be increased. |
