Abstract
This study demonstrates the capacitive type humidity sensor design with novel fringe-effect sensing electrodes and polyimide-pillar array, as shown in Fig. 1. The sensor is implemented by the TSMC 0.18m 1P6M CMOS platform and also monolithically integrated with thermometer and micro heater for performance enhancement. The presented humidity sensing unit has two major merits: (1) polyimide-pillar array: to enhance water vapor absorption and improve the response time; (2) fringe capacitive sensing electrodes: for easy integration with the polyimide-pillars and also to prevent the cross-talk from heater; and the proposed design also features with: (3) vertical integration of micro heater: to prevent water vapor condensation; (4) backside silicon etching: for thermal isolation; (5) monolithic integration of thermometer: for signal calibration. Measurements show the response time of proposed humidity sensor have 43% enhance after plasma etching, and also demonstrate the performances of heater and thermometer. Simulations further indicate a 1.5-fold sensing signal enhancement compared with parallel electrodes.