| 摘要 |
PURPOSE: A sound sensor and a manufacturing method thereof are provided to prevent the sensitivity of a sound sensor from being reduced due to parasitic capacitance by forming the parasitic capacitance of an anchor to be small. CONSTITUTION: A first sacrificial layer(48), which consists of polysilicon, is formed in the upper side of a silicon substrate(32). The crossbeam unit(36a) of a diaphragm(33), which consists of the polysilicon, is formed in the upper unit of a directing unit(48a) on a first sacrificial layer through a second sacrificial layer(47) which consists of a silicon oxide film. The directing unit is formed under an area except for the tip-end unit of the crossbeam unit. A cavity(50) is formed under the area except for the tip-end unit of the crossbeam unit by etching the directing unit from a back chamber which is prepared in the silicon substrate. The second sacrificial layer is removed by etching. An anchor is formed in the lower side of the tip-end unit of the crossbeam unit with the second sacrificial layer.
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