MEMS process and device
First Claim
1. A micro-electrical-mechanical system (MEMS) capacitive microphone comprising:
- first and second electrodes;
a membrane that it is mechanically coupled to the first electrode; and
a back plate that it is mechanically coupled to the second electrode;
wherein the second electrode comprises one or more openings.
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Accused Products
Abstract
A MEMS device comprising a flexible membrane that is free to move in response to pressure differences generated by sound waves. A first electrode mechanically coupled to the flexible membrane, and together form a first capacitive plate. A second electrode mechanically coupled to a generally rigid structural layer or back-plate, which together form a second capacitive plate. A back-volume is provided below the membrane. A first cavity located directly below the membrane. Interposed between the first and second electrodes is a second cavity. A plurality of bleed holes connected the first cavity and the second cavity. Acoustic holes are arranged in the back-plate so as to allow free movement of air molecules, such that the sound waves can enter the second cavity. The first and second cavities in association with the back-volume allow the membrane to move in response to the sound waves entering via the acoustic holes in the back-plate.
137 Citations
40 Claims
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1. A micro-electrical-mechanical system (MEMS) capacitive microphone comprising:
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first and second electrodes; a membrane that it is mechanically coupled to the first electrode; and a back plate that it is mechanically coupled to the second electrode; wherein the second electrode comprises one or more openings. - View Dependent Claims (2, 3, 4, 5)
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6. A micro-electrical-mechanical system (MEMS) capacitive microphone comprising:
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first and second electrodes; a membrane that it is mechanically coupled to the first electrode; and a back plate that it is mechanically coupled to the second electrode; wherein the first and second electrodes each have a diameter that is different to the diameter of the membrane. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A micro-electrical-mechanical system (MEMS) microphone comprising:
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a substrate; first and second electrodes; a membrane that it is mechanically coupled to the first electrode; and a back plate that it is mechanically coupled to the second electrode; and further comprising; a first cavity beneath the membrane, the first cavity formed using a first sacrificial layer; and a second cavity between the first and second electrodes, the second cavity formed using a second sacrificial layer. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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Specification