Patent ID: 8542851
Filing Date: 2013-09-24
Classification: H04R

Abstract:
1. An acoustic sensor comprising: a semiconductor substrate comprising a back chamber; a conductive diaphragm arranged on an upper side of the semiconductor substrate; an insulating fixed film fixed on an upper surface of the semiconductor substrate to cover the conductive diaphragm with a gap; a conductive fixed electrode film arranged on the insulating fixed film at a position facing the conductive diaphragm; an extraction wiring extracted from the conductive fixed electrode film; and an electrode pad, to which the extraction wiring is connected, wherein the acoustic sensor converts an acoustic vibration to change electrostatic capacitance between the conductive diaphragm and the conductive fixed electrode film, wherein a plurality of acoustic perforations are opened in a back plate comprising the insulating fixed film and the conductive fixed electrode film, and wherein an opening rate of the plurality of acoustic perforations is smaller in the extraction wiring and a region in the vicinity thereof than in other regions.