A high-sensitivity piezoelectric microphone and its manufacturing method

Abstract

The invention discloses a piezoelectric microphone with high sensitivity as well as a production method. The piezoelectric microphone comprises a base provided with a cavity and a piezoelectric stacking structure arranged on the base, the cavity in the base is a vacuum vibration cavity, the piezoelectric stacking structure sequentially comprises a bottom electrode, a piezoelectric film and a top electrode, and the base comprises a base bottom layer, a base intermediate layer and a base top layer. The production method comprises the following steps: firstly etching the cavity in the base bottomlayer, then depositing the base intermediate layer, then bonding the base top layer on the base intermediate layer in a vacuum environment, so as to form a vibration cavity, then etching an annular groove on the base top layer, depositing a sacrificial layer in the annular groove, then sequentially depositing the bottom electrode, the piezoelectric film and the top electrode on the base top layer, forming a corrosion hole in the top electrode, and corroding off the sacrificial layer, so that production of the piezoelectric microphone is completed. The piezoelectric microphone disclosed by theinvention can guarantee a vacuum state inside the cavity, air resistance does not exist, strain stress of the piezoelectric film is greatly improved, and a stronger electrical signal is output.

Description

technical field [0001] The invention relates to the technical field of high-sensitivity MEMS sensors, in particular to a microphone, in particular to a high-sensitivity piezoelectric microphone and a manufacturing method. Background technique [0002] A microphone is an energy conversion device that converts sound signals into electrical signals, also known as microphones and microphones. At present, it has been widely used in various electronic fields, military fields, medical fields, etc. In the next ten years, voice interaction will become the main interaction interface of the Internet and devices in consumers' homes. To this end, it is necessary to use MEMS microphone arrays to achieve accurate speech recognition in ambient noise. The existing capacitive MEMS microphone solution is subject to the design of the double-layer film, and the anti-fouling, dust-proof, and waterproof capabilities are limited to a certain extent. In addition, the air interference makes the sig...

AI Technical Summary

Problems solved by technology

The cavity etched in this way is filled with air. When the piezoelectric film starts to vibrate, the air inside the cavity has a certain pressure, which will form air resistance, thereby reducing the pressure difference between the upper and lower piezoelectric films and generating damping. Reduced strain on the piezo film, which ultimately leads to reduced sensitivity

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