Characteristic Evaluation of Silicon-Based MEMS Acoustic/Acceleration Sensor

Due to its smallness in size and economic-saving in batch fabrication, the acoustic micro sensor shows many potential applications in the field of manufacturing and machining monitoring system if it can help to pick up information of sound and vibration signals at specific range. In this paper, brief discussion for the design of the micro-sensor and its fabrication issue will be made. Fundamental frequency testing results by the piezo-electric shaker and acoustic measurement within the water tank are given. A 6-inch silicon wafer fabrication process and sensor design having resonant frequency in the range of 20k–60k Hz are presented and discussed. By selecting appropriate thickness of the structure layer on a SOI wafer, it is possible to customer-make a micro-sensor to sense within a given-range of interest and to apply it in a manufacturing monitoring system.