CPC B81B 1/002 (2013.01) [B81C 1/00047 (2013.01); B81B 2203/0315 (2013.01); B81C 2201/0132 (2013.01); B81C 2203/036 (2013.01)] | 2 Claims |
2. A cavity SOI substrate comprising:
a first silicon substrate having a first surface with a cavity and a second surface opposite the first surface;
a first silicon oxide film having a thickness d1 on the first surface;
a second silicon oxide film having a thickness d2 on a bottom of the cavity;
a third silicon oxide film having a thickness d3 on the second surface; and
a second silicon substrate bonded to the first silicon substrate such that the first silicon oxide film is between the first silicon substrate and the second silicon substrate,
wherein d1≤d3 and d1<d2.
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