Silicon microphone and processing method thereof

Abstract

The invention discloses a silicon microphone and a processing method thereof. The silicon microphone comprises a circuit board substrate, an MEMS sound pressure sensing chip and an ASIC chip. The circuit board substrate is provided with a sound inlet hole which is right opposite to an induction area of the MEMS sound pressure sensor chip, wherein the MEMS sound pressure sensing chip and the ASIC chip are in inverted interconnection with the circuit board substrate and are wrapped in the thermosetting plastic film layer, and the thermosetting plastic film layer is fixedly connected with the circuit board substrate and covers the chip mounting surface of the circuit board substrate. According to the scheme, the conventional thinking mode that the silicon microphone is packaged by the metal shell is changed; the MEMS sound pressure sensing chip and the ASIC chip are wrapped by a thermosetting plastic film. Compared with the prior art, the structure of a metal shell is omitted, the size of a device is greatly reduced, meanwhile, the connection stability of the thermosetting plastic film layer and the circuit board substrate is higher than that of a conventional conductive adhesive, welding operation is not needed, the problem of chip pollution possibly generated in the welding process is avoided, and the combination of the structural stability of a product and the improvement of the yield is effectively achieved.

Description

technical field [0001] The invention relates to the field of packaging of electronic products, in particular to a silicon microphone and a processing method thereof. Background technique [0002] As mobile phones, notebooks, hearing aids, headsets and other electronic products have smaller and smaller size requirements for internal parts, a large number of smaller and better quality silicon microphones are used. Silicon microphones, also known as MEMS microphones, are manufactured based on MEMS technology. Microphone, composed of MEMS boost sensor chip, ASIC chip, sound cavity 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 sound pressure change into a capacitance change, and then convert the ASIC chip capacitance change into an electrical signal to realize "sound-to-sound" conversion . [0003] Most existing silicon microphones include packages such as attac...

AI Technical Summary

Problems solved by technology

[0005] One is to directly use conductive adhesive to bond the metal shell and the circuit board substrate together. This technology can achieve better electrical connection, but the bonding strength of the conductive adhesive is not enough, which may easily lead to insufficient mechanical strength of the product.

[0006] Another way is to use conductive solder paste to weld the metal shell and the circuit board substrate together. This technology can achieve a better electrical connection, but during the soldering process, the solder paste is exposed to high temperature and flux in the solder paste. It is easy to splash under the action, and the solder slag generated by the splash may fall on the MEMS acoustic-electric conversion chip and damage the MEMS acoustic-electric conversion chip, which will eventually lead to the failure of the silicon microphone, which will cause a significant drop in the yield of the silicon microphone

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