Hermetic integration of liquids using high-speed stud bump bonding for cavity sealing at the wafer level

摘要

This paper reports a novel room-temperature hermetic liquid sealing process where the access ports of liquid-filled cavities are sealed with wire-bonded stud bumps. This process enables liquids to be integrated at the fabrication stage. Evaluation cavities were manufactured and used to investigate the mechanical and hermetic properties of the seals. Measurements on the successfully sealed structures show a helium leak rate of better than 10~(-10) mbarL s~(-1), in addition to a zero liquid loss over two months during storage near boiling temperature. The bond strength of the plugs was similar to standard wire bonds on flat surfaces.