Vertical Integration of Force Transmission Structure on Capacitive Cmos-Mems Tactile Force Sensor for Sensitivity Improvement

This study extends the capacitive tactile force sensor array to develop a novel force transmission structure for sensitivity enhancement (Fig. 1). The sensor is designed and implemented using the commercial TSMC 1P6M CMOS process. Merits of the proposed design include: (1) Pillar-array force transmission structure: integrate with capacitive sensing array vertically to effectively transmit the load to each sensing elements to enhance the sensitivity; (2) Rigid force contact interface (i.e. glass bump): can be employed to further enhance the sensitivity. Measurements show that the sensitivity of proposed design with rigid glass bump is 5.04 fF/N (sensing range:5N). Compare with reference design having the same bump size, the sensitivity is increased for 2-fold.