Hermetic integration of liquids in MEMS by room temperature, high-speed plugging of liquid-filled cavities at wafer level

This paper reports a novel room temperature hermetic liquid sealing process based on wire bonded “plugs” over the access ports of liquid-filled cavities. The method enables liquids to be integrated already at the fabrication stage. Test vehicles were manufactured and used to investigate the mechanical and hermetic properties of the seals. A helium leak rate of better than 10^-10 mbarL/s was measured on the successfully sealed structures. The bond strength of the “plugs” were similar to standard wire bonds on flat surfaces.