A self-packaged self-heated thermal wind sensor with high reliability and low power consumption

Abstract

A self-packaged self-heated thermal wind sensor was designed, fabricated and measured for the first time in this paper. To achieve a low power and reliable sensor, a newtype silicon-in-glass (SIG) substrate with anisotropic thermal conductivity was introduced. In this substrate, the embedded vertical silicon vias are used to realize the thermal interconnections between the sensor and the wind, while the horizontal thermal conduction between the thermistors is isolated effectively by the glass. The substrate is based on a glass reflow process and the sensor was fabricated on this substrate by using a lift-off process. The whole process only need three masks. At last, we performed a wind tunnel test in constant voltage (CV) mode, and the measurement results show that the thermal wind sensor can measure wind speeds up to 17.5 m/s, and the measured sensitivities of the sensor with different applied voltages of 0.8 V, 0.9 V, and 1 V are respectively 6.3 mV/(m/s), 9.52 mV/(m/s), and 14.17 mV/(m/s) at zero-flow point. The corresponding power consumption of the sensor with different voltages are respectively 12.3 mW, 15.57 mW and 19.23 mW. Measurement results also show that wind direction in a full range of 360° with an error less than 6° could be obtained.