Design and implementation of an extremely large proof-mass CMOS-MEMS capacitive tilt sensor for sensitivity and resolution improvement

This study employs the low temperature UV-glue dispensing and curing processes to bond a bulk block on a suspended CMOS MEMS stage to increase the proof-mass of tilt sensor. Thus, the sensitivity and resolution of CMOS MEMS capacitive-type tilt sensor are significantly improved. Such simple post-CMOS process inherits from the mature technology for packaging. In application, this study successfully demonstrates the bonding of a bulk solder ball with a tilt sensor fabricated using the standard TSMC 0.35μm 2P4M CMOS process. Measurements show the sensitivity is increased for 3.4-fold, and the resolution is improved from 1° to 0.1v, after adding the solder ball. Note that the sensitivity can be further improved by reducing the parasitic capacitance and the mismatch of sensing fingers caused by solder ball.