Abstract: A sound detecting mechanism capable of forming a diaphragm and a back electrode on a substrate by a simple process includes acoustic holes corresponding to perforations formed on a front surface of a substrate. A second protective film, a sacrificial layer and a metal film are laminated on the front surface in a portion corresponding to the acoustic holes. The substrate is etched from the back surface thereof to a depth reaching the acoustic holes to form an acoustic opening. Subsequently, by effecting an etching from the back surface of the substrate through the acoustic holes, the sacrificial layer is removed and a void area is formed between the diaphragm made of the metal film, the substrate and the formed perforations. The sacrificial layer that remains after the etching is used as a spacer for maintaining a gap between the back electrode and the diaphragm.

Abstract: A sound detecting mechanism is provided which forms a diaphragm with a required thickness by thickness control and yet restrains distortion of the diaphragm to provide high sensitivity. The sound detecting mechanism comprises a pair of electrodes forming a capacitor on a substrate A in which one of the electrodes is a back electrode C forming perforations Ca therein corresponding to acoustic holes and the other of the electrodes is a diaphragm B. The diaphragm B is mounted on the substrate A while the back electrode C is mounted in a position opposed to the diaphragm B across a void F to be supported by the substrate A, the back electrode C being formed by polycrystal silicon of 5 ?m to 20 ?m in thickness.

Abstract: A sound detecting mechanism capable of forming a diaphragm and a back electrode on a substrate by a simple process includes acoustic holes corresponding to perforations formed on a front surface of a substrate. A second protective film, a sacrificial layer and a metal film are laminated on the front surface in a portion corresponding to the acoustic holes. The substrate is etched from the back surface thereof to a depth reaching the acoustic holes to form an acoustic opening. Subsequently, by effecting an etching from the back surface of the substrate through the acoustic holes, the sacrificial layer is removed and a void area is formed between the diaphragm made of the metal film, the substrate and the formed perforations. The sacrificial layer that remains after the etching is used as a spacer for maintaining a gap between the back electrodes and the diaphragm.

Abstract: A sound detecting mechanism is provided which forms a diaphragm with a required thickness by thickness control and yet restrains distortion of the diaphragm to provide high sensitivity. The sound detecting mechanism comprises a pair of electrodes forming a capacitor on a substrate A in which one of the electrodes is a back electrode C forming perforations Ca therein corresponding to acoustic holes and the other of the electrodes is a diaphragm B. The diaphragm B is mounted on the substrate A while the back electrode C is mounted in a position opposed to the diaphragm B across a void F to be supported by the substrate A, the back electrode C being formed by polycrystal silicon of 5 ?m to 20 ?m in thickness.

Abstract: A sound detecting mechanism is provided which forms a diaphragm with a required thickness and yet restraining distortion of the diaphragm to provide high sensitivity. The sound detecting mechanism comprises a pair of electrodes forming a capacitor on a substrate A in which one of the electrodes is a back electrode C forming perforations Ca therein corresponding to acoustic holes and the other of the electrodes is a diaphragm B. A silicon nitride film 303 is provided on the side adjacent a base of the substrate A with respect to a membrane acting as the diaphragm B formed on the substrate A.