A Capacitive Pressure Sensor Using Hybrid Silicon-Glass Structure for Hermetic Wafer Level Packaging

A design of barometric capacitive pressure sensor is presented in this paper, which is compatible with the standard CMOS process, and a new wafer level packaging is used to seal the vacuum cavity with a glass-silicon hybrid wafer which has a certain pattern. The electrodes of the sensor are leaded out by through silicon via (TSV) technology from back side of the silicon substrate. Mechanical characteristics of the sensor are analyzed by ANSYS. The initial gap of both electrodes formed the capacitor is 2 mu m, and the size of the square membrane is 700 mu m. The simulation results show the sensitivity of the sensor is 2.84fF/hPa, and the nonlinearity of the device is less than 1.1% over a dynamic range 700-1100 hPa. It is shown that the device is suitable to be used in measuring the barometric pressure.