Integration of Infrared Sensor and Pressure/Humidity/Temperature CMOS-MEMS Environmental Sensing Hub by Local Vacuum Packaging

This research presents the integrated infrared sensor (thermopile), pressure sensor, humidity sensor and thermometer to implement an environmental sensing hub. This sensing hub is developed based on the commercial CMOS-MEMS platform (TSMC 0.18μm 1P6M) and low temperature die-level bonding process. Features of the proposed design are: (1) monolithically integrated 4 kinds of sensing units on CMOS chip including thermopile, pressure sensor, humidity sensor and thermometer, (2) micro packaging providing local vacuum chamber for thermopile to avoid environment influence, (3) vertically integrated thermopile and silicon cap to filter out visible light. Measurements show the thermopile with responsivity of 1.1μV/K, pressure sensor with sensitivity of 0.061fF/Torr, and the sealing chamber with vacuum level about 520Torr, humidity sensor with sensitivity of 1.29fF/%RH, and thermometer with sensitivity of 0.72mV/°C.