5.7 A MEMS Coriolis Mass Flow Sensor with 300 μ g/h/√Hz Resolution and ± 0.8mg/h Zero Stability

Precision flow sensors are widely used in the pharmaceutical, food, and semiconductor industries to measure small amounts (<1 gram/hour) of liquids and gases. MEMS thermal flow sensors currently achieve state-of-the-art performance in terms of resolution, size, and power consumption [1, 3]. However, they only measure volumetric flow, and so must be calibrated for use with specific liquids [1] or gases [2, 3]. In contrast, Coriolis flow sensors measure mass flow and thus do not need calibration for specific fluids. Furthermore, their resonance frequency can be used as a measure of fluid density. These features enable significant size, cost, and complexity reductions in low-flow microfluidic systems. Although much progress has been made, miniature [4] and MEMS [5– 7] Coriolis mass flow sensors are still outperformed by their thermal counterparts, especially in terms of resolution and long-term stability.