A Novel 2-D Capacitive Silicon Flow Sensor

A novel 2-D capacitive silicon flow sensor which can detect both air flow velocity and direction is presented in this paper. The sensor has a sensing disk that is connected with the anchor by "spring-like beam". The flow induced drag force makes the disk shift, and eventually changes the capacitance. The influences of the flow on the structure are analyzed by FEA. A fascination process based on anodic bonding and ICP (Inductive Coupled Plasma) etch is proved to be a valid one. The fabricated sensor is 4.8 mm in diameter and 0.12 mm in height, with 2.4 pF of initial capacitance in each quadrant. Wind flow velocity from 1 m/s to 10 m/s and flow direction angle of 360 degrees can be measured successfully. The experiment results show a reasonable agreement with the simulation.