Method of manufacturing a membrane sensor
First Claim
1. A method of manufacturing a membrane sensor, comprisingselecting into use a layer-structured preform comprising a first layer, a second layer made of conductive material, and an insulating layer between the first and second layers;
- removing material from the first layer by etching a cavity in the first layer, the cavity extending through the first layer as far as to the insulating layer;
growing a membrane of conductive material on the insulating layer through the cavity formed in the first layer, the membrane joining to the walls of the cavity, forming a dense wall in the cavity;
removing material from the second conductive layer by etching perforations in the second conductive layer, the perforations extending through the second conductive layer as far as to the insulating layer and being situated in a finished membrane sensor at the point of the cavity but on the side opposite to the insulating layer; and
removing the insulating layer from the area between the perforations and the cavity.
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Accused Products
Abstract
This invention relates to a differential pressure sensor, one embodiment of which is a microphone. The differential pressure sensor comprises: a flexible membrane (7) made of conductive material, which membrane forms a first electrode of the differential pressure sensor, and a perforated plate (6) made of conductive material, which plate is essentially more rigid than said membrane (7), which plate is arranged at a distance from the membrane, and which plate forms a second electrode of the differential pressure sensor. In order to provide a differential pressure sensor with as good properties as possible, the differential pressure sensor comprises a substrate (4), a cavity (10) extending through the substrate, the walls of which cavity are formed of said substrate (4). The membrane (7) is closely connected to the walls of the cavity (10), whereby the membrane forms a dense wall in said cavity, and said perforated plate (6, 6′) has been attached to the substrate with an insulating layer (5).
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Citations
18 Claims
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1. A method of manufacturing a membrane sensor, comprising
selecting into use a layer-structured preform comprising a first layer, a second layer made of conductive material, and an insulating layer between the first and second layers; -
removing material from the first layer by etching a cavity in the first layer, the cavity extending through the first layer as far as to the insulating layer;
growing a membrane of conductive material on the insulating layer through the cavity formed in the first layer, the membrane joining to the walls of the cavity, forming a dense wall in the cavity;
removing material from the second conductive layer by etching perforations in the second conductive layer, the perforations extending through the second conductive layer as far as to the insulating layer and being situated in a finished membrane sensor at the point of the cavity but on the side opposite to the insulating layer; and
removing the insulating layer from the area between the perforations and the cavity. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A differential pressure sensor comprising
a flexible membrane made of conductive material, which membrane forms a first electrode of the differential pressure sensor; - and
a perforated plate made of conductive material, which plate is essentially more rigid than said membrane, which plate is arranged at a distance from the membrane, and which plate forms a second electrode of the differential pressure sensor, wherein the differential pressure sensor also comprises a substrate, a cavity extending through the substrate, the walls of which cavity are formed of said substrate;
the membrane is closely joined to the walls of the cavity, whereby the membrane forms a dense wall in said cavity, and said perforated plate is attached to the substrate with an insulating layer. - View Dependent Claims (9, 10, 11, 12)
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13. A microphone comprising:
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a flexible membrane made of conductive material, which membrane forms a first electrode of the microphone; and
a perforated plate made of conductive material, which plate is essentially more rigid than said membrane, which plate is arranged at a distance from the membrane, and which plate forms a second electrode of the microphone, wherein the microphone further comprises a substrate, a cavity extending through the substrate, the walls of which cavity are formed of said substrate;
the membrane is closely joined to the walls of the cavity, whereby the membrane forms a wall in said cavity; and
said perforated plate has been attached to the substrate with an insulating layer. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification