A solid state silicon-based electret condenser microphone Comprising a silicon transducer chip. The transducer chip includes a back plate and a diaphragm arranged substantialy parallel to each other with a small air gap in between, thereby forming an electrical capacitor. The diaphragm is movable relative to the back plate in response to incident sound.
An integrated qin yi electronic electronic circuit chip or ASIC is an electrically coupled to the transducer chip. An intermediate layer fixes the transducer chip to the integrated electronic circuit chip with the transducer chip has a first side of the intermediate layer and the integrated electronic circuit chip on a second side of the intermediate layer opposite the first side. The intermediate layer has a sound inlet on the same side as the ASIC giving access of sound to the diaphragm.
In the hearing instruments industry one of the primary goals is to make hearing instruments of small size while still Maintaining good electro acoustic performance and Operability giving good user friendliness and satisfaction. Technical performance data compris such as sensitivity, stability, compactness, robustness and insensitivity to electromagnetic interference and to other external and environmental conditions. In the past, several Attempts have been made to make Smaller microphones while still Maintaining good technical performance data.
EP 561 566 discloses a solid state condenser microphone having a transducer chip and, on the same chip, an electronic circuit and a cavity forming an opening or sound inlet for the transducer. The techniques and processes for manufacturing such electronic circuitry are quite different from the techniques and processes used in manufacturing the transducer elements. Consequently a chip having Bothan an electronic circuit and an opening therein requires two (or Possibly more) separate stages of production, Usually at different facilities.