Abstract: A vibrating electrode plate 24 that senses a sound pressure faces a counter electrode plate 25 to form a capacitance type acoustic sensor. Acoustic perforations are opened in the counter electrode plate 25 in order to allow vibration to pass through. The acoustic perforations opened in the counter electrode plate 25 include plural acoustic perforations 31 having a relatively small opening area and one acoustic perforation 36 having a relatively large opening area. The acoustic perforations 31 and 36 are disposed into a lattice shape at equal intervals. Assuming that L is a width of a diaphragm 28, in the counter electrode plate 25, the acoustic perforation 36 having the large opening area is provided within a circular region a having a radius r=L/4 around a position facing a center of the diaphragm 28.

Abstract: A method for manufacturing a vibration sensor including forming a sacrifice layer at one part of a front surface of a semiconductor substrate of monocrystalline silicon with a material isotropically etched by an etchant for etching the semiconductor substrate, forming a thin film protective film with a material having resistance to the etchant on the sacrifice layer and the front surface of the semiconductor substrate at a periphery of the sacrifice layer, forming a thin film of monocrystalline silicon, polycrystalline silicon, or amorphous silicon on an upper side of the sacrifice layer, opening a backside etching window in a back surface protective film having resistance to the etchant for etching the semiconductor substrate formed on a back surface of the semiconductor substrate, forming a through-hole in the semiconductor substrate by etching the semiconductor substrate anisotropically by using crystal-oriented etching by applying the etchant from the back surface window, then etching the sacrifice layer

Abstract: A vibration electrode plate 112 is formed on the upper face of a silicon substrate 32 with an insulating coat film 35 interposed in between. An opposing electrode plate 113 is placed on the vibration electrode plate 112 with an insulating coat film interposed in between, and acoustic holes 40 are opened through the opposing electrode plate 113. Etching holes 36 and 104, each having a semi-elliptical shape, are opened through the vibration electrode plate 112 and the opposing electrode plate 113 so as to face each other longitudinally. A concave section 37 having a truncated pyramid shape is formed in the upper face of the silicon substrate 32, by carrying out an etching process through the etching holes 36 and 104. The vibration electrode plate 112 is held in the silicon substrate 32 by a holding portion 112 placed between the etching holes 36.

Abstract: A vibrating electrode plate 24 that senses a sound pressure faces a counter electrode plate 25 to constitute a capacitance type acoustic sensor. In the counter electrode plate 25, acoustic perforations 31 are opened in order to pass vibration, and plural projections 36 are provided on a surface facing the vibrating electrode plate 24. An interval between the projections 36 is decreased in a region where the vibrating electrode plate 24 has high flexibility to easily generate local sticking with the counter electrode plate 25. The interval between the projections 36 is increased in a region where the vibrating electrode plate 24 has low flexibility to hardly generate local sticking with the counter electrode plate 25. The projections thus arranged prevent firm fixing of the vibrating electrode plate to the counter electrode plate and interruption of vibration of the vibrating electrode plate.

Abstract: A method for manufacturing a vibration sensor including forming a sacrifice layer at one part of a front surface of a semiconductor substrate of monocrystalline silicon with a material isotropically etched by an etchant for etching the semiconductor substrate, forming a thin film protective film with a material having resistance to the etchant on the sacrifice layer and the front surface of the semiconductor substrate at a periphery of the sacrifice layer, forming a thin film of monocrystalline silicon, polycrystalline silicon, or amorphous silicon on an upper side of the sacrifice layer, opening a backside etching window in a back surface protective film having resistance to the etchant for etching the semiconductor substrate formed on a back surface of the semiconductor substrate, forming a through-hole in the semiconductor substrate by etching the semiconductor substrate anisotropically by using crystal-oriented etching by applying the etchant from the back surface window, then etching the sacrifice layer

Abstract: A vibration electrode plate 112 is formed on the upper face of a silicon substrate 32 with an insulating coat film 35 interposed in between. An opposing electrode plate 113 is placed on the vibration electrode plate 112 with an insulating coat film interposed in between, and acoustic holes 40 are opened through the opposing electrode plate 113. Etching holes 36 and 104, each having a semi-elliptical shape, are opened through the vibration electrode plate 112 and the opposing electrode plate 113 so as to face each other longitudinally. A concave section 37 having a truncated pyramid shape is formed in the upper face of the silicon substrate 32, by carrying out an etching process through the etching holes 36 and 104. The vibration electrode plate 112 is held in the silicon substrate 32 by a holding portion 112 placed between the etching holes 36.