Ultra Low Leak Rate Measurement for MEMS Resonant Devices Based on Constant Vibration Control

This paper proposed an ultra-low leak rate measurement method for MEMS resonant devices, which monitors the internal pressure change of the encapsulated cavity via the drive voltage under constant vibration control. Compared with the conventional He gas leak detection$\left(10^{-9} \sim 10^{-10} ~\text{Pa} \cdot ~\mathrm{m}^{3} / \mathrm{s}\right)$, the minimum detectable leakage rate of this approach features$6 \sim 7$orders of magnitude decreasing. By calibrating the Pressure-Drive voltage ($\mathrm{P}-\mathrm{V}$) curve of an unpackaged microstructure, the leak rate of the devices in the same batch can be measured at wafer-level before product packaging.