Electret condenser microphone and manufacturing method thereof

Abstract

PROBLEM TO BE SOLVED: To achieve prevention of leakage of the charges stored in electrets to the outside, in an electret condenser microphone.

SOLUTION: An electret condenser microphone includes a membrane 2 (lower electrode) provided with an electret 4 and an upper electrode 1 opposed to the membrane 2 with an air gap 3 interposed. In manufacture of the electret condenser microphone, degasification is performed prior to performing water repellent finishing on the inside of the air gap 3.

COPYRIGHT: (C)2008,JPO&INPIT

Description

technical field [0001] The present invention relates to a manufacturing method of an acoustic detection mechanism, in particular to an electret condenser microphone formed by using Micro Electro Mechanical Systems (MEMS: Micro Electro Mechanical Systems) technology and a manufacturing method thereof. Background technique [0002] An electret condenser microphone is an ultra-small microphone with a parallel plate capacitor. Its working principle is that if one electrode of the capacitor vibrates in response to a change in sound pressure, the electrostatic capacitance of the capacitor will change, and the change will eventually be converted into a voltage signal. [0003] There are two types of electret condenser microphones, one is a bonded electret condenser microphone made by bonding multiple parts together, and the other is the use of semiconductor technology, that is, MEMS technology to make the entire microphone All-in-one integrated electret condenser microphone. [00...

AI Technical Summary

Problems solved by technology

[0015] However, since the electret condenser microphone has a structure in which the electret film passes through the sound transmission hole and is exposed to the air outside the cylinder, when the electret condenser microphone is used between a high-temperature and humid environment and a low-temperature and low-humidity environment, In other words, when the electret condenser microphone is used in an adverse environment of condensation water droplets, the inside of the gap with a small area of ​​the opening (sound transmission hole and sound leakage hole) communicating with the outside air becomes particularly prone to condensation. Unfavorable environment for water droplets

As a result, the vibrating membrane and the fixed membrane are tightly pressed together due to condensation droplets, and the charge accumulated in the electret can easily leak into the air outside the cylinder, which is a potential problem.

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