| 摘要 |
This method for manufacturing a diaphragm-type resonant MEMS device comprises: a lamination step wherein a first silicon oxide film that is formed by thermal oxidation or a process comprising a heat treatment at 900°C or more, a second silicon oxide film that has a stress having an absolute value of 100 or less [MPa], a lower electrode, a piezoelectric film and an upper electrode are sequentially laminated in this order on a first surface of a silicon substrate; and an etching step wherein a surface of the silicon substrate, said surface being on the reverse side of the first surface, is etched by deep reactive ion etching until the first silicon oxide film is exposed, thereby forming a recessed portion. If t1 is the film thickness of the first silicon oxide film, t2 is the film thickness of the second silicon oxide film and R2 is t2/(t1 + t2), namely the ratio of the film thickness of the second silicon oxide film relative to the sum of the film thickness of the first silicon oxide film and the film thickness of the second silicon oxide film, t1, t2 and R2 satisfy relational expressions 0.10 [μm] ≤ t1 ≤ 2.00 [μm] and R2 ≥ 0.70. |
