| 摘要 |
PURPOSE:To reduce breakdowns of diaphragms and to improve the yield by providing a dielectric thin film over a substrate where a piezoelectric thin film and electrodes are formed, and then carrying out an anisotropic etching treatment. CONSTITUTION:The lower electrode 23, piezoelectric thin film 24, and upper electrode 25 are formed successively on one surface 20a of the substrate including a silicon wafer 20. Then, the dielectric thin film 26 which is not corroded by an anisotropic etchant is formed covering the piezoelectric thin film 24 and electrodes 23 and 25. The other surface 20b of the wafer 20 is etched on anisotropic basis after the formation of the dielectric thin film to form a recessed part 27. Thus, the diaphragm is formed, so aftertreatments following the diaphragm formation are reduced. Consequently, breakdowns of the diaphragms are reduced to improve the yield. |
