A kind of preparation method of mems structure

Abstract

The invention discloses a method for preparing a micro electro mechanical system (MEMS) structure, which comprises the following steps of etching a peripheral area on the front surface of a substrateto form a plurality of parallel second grooves, depositing and forming a piezoelectric composite vibration layer on the substrate, wherein the piezoelectric composite vibration layer formed at the bottoms and the side walls of the second grooves forms a first corrugated part; depositing and forming a mass block in the middle area of the piezoelectric composite vibration layer; etching the exposedsubstrate outside the piezoelectric composite vibration layer to form a first groove; etching the back surface of the substrate to form a cavity, wherein the first groove is adjacently arranged at theperiphery of the cavity, the piezoelectric composite vibration layer is formed right above the cavity, and part of the substrate located between the first groove and the cavity supports the piezoelectric composite vibration layer. According to the MEMS structure manufactured by the method, the displacement and the deformation of the piezoelectric composite vibration layer under the action of sound pressure are improved, the residual stress is reduced, and the sensitivity of the MEMS structure is further improved.

Description

technical field [0001] The present application relates to the field of semiconductor technology, in particular, to a method for preparing a MEMS (abbreviation for MicroelectroMechanical Systems, microelectromechanical systems) structure. Background technique [0002] MEMS microphones (microphones) mainly include two types: capacitive and piezoelectric. MEMS piezoelectric microphone is a microphone prepared by microelectromechanical system technology and piezoelectric thin film technology. Due to the use of semiconductor planar technology and bulk silicon processing technology, it has small size, small volume and good consistency. At the same time, compared with condenser microphones, there are advantages such as no need for bias voltage, wide operating temperature range, dustproof, waterproof, etc., but its sensitivity is relatively low, which restricts the development of MEMS piezoelectric microphones. Among them, the large residual stress of the vibrating membrane is an i...

AI Technical Summary

Problems solved by technology

At the same time, compared with condenser microphones, there are advantages such as no need for bias voltage, wide operating temperature range, dustproof, waterproof, etc., but its sensitivity is relatively low, which restricts the development of MEMS piezoelectric microphones.

Among them, the large residual stress of the vibrating membrane is an important reason for its low sensitivity.

[0003] There is no effective solution to the problem of how to reduce the residual stress of the piezoelectric MEMS structure and improve the deformation of the vibrating membrane in related technologies.

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