MEMS MIC with front sound cavity and rear sound cavity

Abstract

The invention discloses an MEMS MIC with a front sound cavity and a rear sound cavity. The appearance structure is kept unchanged. An expanded rear sound cavity communicated with the rear sound cavityis formed by adding a cavity plate on a PCB. The MEMS MIC internal structure is changed. The industry common problem that the rear sound cavity of the advancing MEMS MIC is small is fundamentally solved. The utilization rate of the internal space of the MIC is maximized. The rear sound cavity volume is maximized. The problem that the volume of a traditional rear sound cavity completely depends onthe size of an MEMS sound pressure sensor chip is thoroughly solved. The current situation that the rear sound cavity volume is too small and the front and rear sound cavity volumes are not matched can be effectively improved. The size of the rear sound cavity is increased, so that the amplitude of the MEMS chip is increased. The pickup sensitivity is remarkably improved. The product sensitivityis remarkably improved under the condition that the appearance structure and the overall size are kept unchanged. The product voice is clear, natural and easy to identify, and the product tone qualityis remarkably improved.

Description

technical field [0001] The invention relates to the field of MEMS MICs, in particular to a MEMS MIC with front and rear sound chambers. Background technique [0002] MEMS MIC is a microphone based on MEMS technology, consisting of MEMS sound pressure sensor chip, ASIC chip, front and rear sound chambers and RF suppression circuit. The MEMS sound pressure sensor is a miniature capacitor composed of a silicon diaphragm and a silicon back plate, which can convert the change of sound pressure into a change of capacitance, and then the ASIC chip converts the change of capacitance into an electrical signal to realize "sound-to-electricity" conversion . Among them, the MEMS chip divides the cavity formed by the MEMS shell into a front sound cavity and a rear sound cavity. The rear sound cavity of the forward-sounding MEMS MIC is mainly formed by bonding the MEMS chip and the PCB through glue. In this way, the volume of the rear sound cavity depends on the volume of the back cavit...

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Problems solved by technology

In this way, the volume of the rear sound cavity depends on the volume of the back cavity of the MEMS chip, and the adjustable range is limited. The size of the MEMS MIC rear sound cavity is very limited. The small volume of the rear sound cavity limits the sound pickup performance of the MEMS chip, making it difficult to further improve the sensitivity of the MEMS MIC with the current structure.

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