Evaluation of Capacitive Humidity Sensor with Polyimide as Sensing Material

In this paper, capacitive humidity sensor was fabricated on 200mm CMOS Al Back End of Line (BEOL). Al interconnect layer with metal FORK structure was used as electrode of the capacitor, and polyimide was used as sensing material which was filled into metal FORK electrode structure. After fabrication, its humidity sensing performance was evaluated and compared with standard sensor, including IV curve, capacitance variation with different relative humidity (RH%), recovery time, etc. Based on the measured data, the humidity sensor device based on polyimide material can well meet the humidity measurement requirements.