A Novel Piezoresitive Microphone MEMS Sensor For Aerospace Applications

In this paper we present a microphone sensor for aerospace applications. The novel microphones can be integrated into large arrays for measuring unsteady pressure fluctuations underneath the turbulent boundary layer (TBL), which can be applied to predict the cabin noise excitation. The microphone array has a high spatial resolution due to the small distance between its microphone elements. The microphone sensor is featuring a very thin membrane created by a special technology combining SOI wafer bonding and thinning and TSV (Through Silicon Vias) for contacting from the backside. The membrane thickness is about $4 \mu \mathrm{m}$. The membrane has a small hole in the middle (diameter about $7 \mu \mathrm{m})$ drilled by using laser technique. The TSVs are etched in the carrier wafer or interposer by using a KOH or DRIE/BOSCH process.