| 摘要 |
<p>A substrate 20 is prepared. "A piezoelectric material layer 32a which has not been fired" and which will become a piezoelectric membrane is formed above a first principal surface 20a of the substrate 20. A first mask 131 is formed above the piezoelectric material layer 32a. "The piezoelectric material layer 32a existing within a portion where the first mask 131 does not exist" is eliminated by injecting a blast media including at least one of abrasive grains or an organic solvent onto the first principal surface 20a of the substrate 20. Thereafter, the first mask 131 is eliminated, and the piezoelectric material layer 32a is fired. The substrate has a hollow portion, however, it does not necessarily have the hollow portion.</p> |
