| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a BAW resonance device capable of improving crystallinity of a piezoelectric layer, improving the mechanical quality index and being reduced in size and made rugged, and to provide a method of manufacturing the device. <P>SOLUTION: In this BAW resonance device, resonators 3, each having a piezoelectric layer 32 between a lower electrode 31 and an upper electrode 33, are formed on one surface side of a support substrate 1, and cavities 1a for exposing surfaces of the lower electrodes 31 of the resonators 3 on the support substrate 1 side are formed on the support substrate 1; the piezoelectric material of the piezoelectric layer 32 is a PZT-based material, and the entire region, in plan view of the piezoelectric layer 32, is formed on the lower electrode 31; the support substrate 1 has a laminated structure for an upper-layer substrate 11 and a lower-layer substrate 12, having thicknesses that differ mutually; and the upper-layer substrate 11 is formed of a single-crystal MgO substrate and thinner than the lower-layer substrate 12, wherein each cavity 1a is formed with a cross-sectionally-trapezoidal opening 11a bored in the thickness direction of the upper-layer substrate 11 by wet anisotropic etching, by using the crystal orientation dependence of the etching speed. <P>COPYRIGHT: (C)2010,JPO&INPIT |
