| CPC B81B 3/0021 (2013.01) [H04R 31/006 (2013.01); B81B 2201/0257 (2013.01); B81B 2203/0127 (2013.01); B81B 2203/0315 (2013.01); H04R 2201/003 (2013.01)] | 9 Claims |

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1. A MEMS microphone comprising:
a substrate with a back cavity;
a capacitive system supported by the substrate, including a back plate and a vibration diaphragm fixed on the substrate at a side of the back plate close to the substrate; wherein
the back plate includes a middle part, a fixed part surrounding the middle part and being fixed to the substrate;
a thickness of the fixed part is greater than a thickness of the middle part;
the fixed part includes a first surface away from the substrate and a second surface opposite to the first surface; and
each of the first surface and the second surface includes a first arc connected to the middle part and protruding away from the substrate and a second arc connected to the first arc and protruding away from the substrate, both the first arc and the second arc on the second surface are spaced apart from the vibration diaphragm.
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