Acoustic methods for detection of specific failure modes in capacitive MEMS microphones

Abstract

Capacitive MEMS microphones are found today in the majority of mobile phones. Methods to detect failures easily and non-invasively during the manufacturing or usage of microphones, and to maintain microphones performance have become of critical importance to microphones and mobile phones manufacturers. This article provides four new methods, based solely on acoustic measurements to measure pull-in voltage and snapback voltage ranges, and to identify the states of electrostatic capture for single membrane capacitive MEMS microphones. 100% success rate in detecting membrane capture events is demonstrated for this type of device.