Realization of MEMS flush-mounted integration using Through Silicon Vias on thermal micro-sensors designed for aeronautics

This paper reports the realization of Through Silicon Vias (TSV) filled with electrodeposited copper (Cu) for the fabrication of aeronautics dedicated thermal MEMS (Micro Electro-Mechanical Systems) sensors. The micro-sensors are designed to measure the skin friction of the airflow on a structure. For testing in real conditions on an aircraft, a solid integration is required. Therefore, a production batch was realized with TSV process developed and added to the sensor manufacturing process. The TSV process is composed of several steps including the realization of the metal membrane based electrode for the electrodeposition, deep silicon dry etching, copper filling and polishing. The sensors process followed the TSV process and the TSV equipped sensors chip were successfully fabricated. The electro-thermal characterizations of the TSV sensors chip demonstrated the same performances as the chips without TSV. Then, the micro-sensors were packaged allowing a flush-mounted integration on objects. A first test was done in wind tunnel before testing on flight.