A Wafer-Level Encapsulated Cmos Mems Thermoresistive Calorimetric Flow Sensor With Integrated Packaging Design

In this paper, we presented a wafer-level encapsulated Thermoresistive Micro Calorimetric Flow (TMCF) sensor with the integrated packaging by using the proprietary InvenSense CMOS MEMS technology. For the nitrogen gas flow from -26m/s to 26m/s, the pulsed operated TMCF sensor (device size = 3.4mm(2)) under the Constant Temperature Difference (CTD) mode achieved a normalized sensitivity of 112.4 mu V/(m/s)/mW with respect to the input heating power. Besides, the measured TMCF sensor response time (tau(max)< 3.63ms) shows good agreement with a theoretical model. With the pulsed operation, the proposed low-power TMCF sensor will be a promising digital CMOS MEMS flow sensor for the Internet of Things (IoT), especially for smart building/home.