A tunable range/sensitivity CMOS-MEMS capacitive tactile sensor with polymer fill-in technique

This paper presents a capacitive type CMOS-MEMS tactile-sensor containing a sensing gap filled with polymer. The fabrication process allows the changing of polymer material easily. In application, the tactile-sensor and sensing circuits have been designed and implemented using TSMC 0.35 mum 2P4M CMOS process, and in-house post-CMOS releasing and polymer-filling processes. Measurement results demonstrate the sensitivity and sensing range of CMOS-MEMS tactile-sensor are easily tuned by changing the polymer materials. The experiment results show that the sensitivity of the tactile sensor increases from 18.38 to 69.36 mV/mN by varying the PDMS filling. Moreover, the maximum sensing load is also increased.