A kind of mems microphone structure and manufacturing method thereof

Abstract

The invention discloses an MEMS microphone structure which comprises a substrate, a first dielectric layer, a lower electrode layer, an upper electrode structure, an air gap and a release hole. The substrate includes a cavity; the first dielectric layer includes a through hole communicated with the cavity; the lower electrode layer comprises a backplate and a first leading-out portion which are connected with each other, and the backplate is placed over the through hole; the upper electrode structure comprises a diaphragm formed by an upper electrode layer, a second leading-out portion connected with the diaphragm, and an annular groove filled with an insulating layer; the bottom of the annular groove is supported by the lower electrode layer and placed in areas beyond the backplate; the insulating layer extends horizontally inwardly from the upper end of the inner sidewall of the annular groove to position under the diaphragm so that the diaphragm is hung over the backplate via the annular groove; the air gap is formed between the diaphragm and the backplate; and the release hole is formed in the backplate and communicated with the air gap and the through hole. According to the invention, the backplate and diaphragm can be avoided from damage or falling off in the release process.

Description

technical field [0001] The invention relates to the technical field of micro-electro-mechanical systems, in particular to a MEMS microphone structure and a manufacturing method thereof. Background technique [0002] Microphones are divided into dynamic microphones and condenser microphones. The traditional dynamic microphone consists of a coil, a diaphragm and a permanent magnet. It is based on the principle that the movement of the coil in a magnetic field generates an induced current; while the main structure of a capacitive microphone is two capacitive plates, namely the diaphragm (Diaphragm ) and the back electrode (Backplate), its working principle is that the sound pressure causes the deformation of the vibrating membrane, resulting in a change in the capacitance value, which is converted into an electrical signal output. [0003] MEMS microphones are by far one of the most successful MEMS products. MEMS microphone is a microphone manufactured by surface processing o...

AI Technical Summary

Problems solved by technology

A problem with this method is that when the release process is performed to remove the dielectric layer between the vibrating membrane and the back electrode and between the back electrode and the substrate to form an air gap, the release process time needs to be strictly controlled. Long time will completely remove the dielectric layer under the back electrode and cause the back electrode to fall off

Images