| 摘要 |
A semiconductor microphone chip is provided to form a condenser structure composed of a vibration layer and a back electret by including a vibration layer with a beam structure of a predetermined wavelength type. A periphery of a vibration layer(21) is connected to an edge frame and a support part(22) through a beam of a water mark type. A micro concave surface and a small hole are aligned in the periphery of the vibration layer. The micro concave surface protrudes downward to form an interval with the upper surface of a back electret(23). When a voltage is applied to a condenser structure composed of the vibration layer and the back electret, the micro concave surface is prevented from being connected to the vibration layer and the back electret and the sound leaking to the beam portion is reduced. When a microphone chip is fabricated, a sacrificial layer originally existing between the vibration layer and the back electret is discharged through a small hole and a sound hole(26) on the back electret. The substrate is silicon as a semiconductor material. The support part is an insulation material. The insulation material is a silicon oxide.
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