Detailed Investigations of Inner Cavity Pressure of MEMS Devices Sealed by Wafer Bonding

摘要

Hermetic sealing is important regarding functionality and reliability for MEMS components. Typically this sealing is done at the wafer level using wafer bonding, which simultaneously also provides mechanical protective caps. An existing test structure for inner cavity pressure measurement, utilizing the pressure dependence of heat transfer in gasses, is used for detailed investigations of factors, which influence the inner cavity pressure in the wafer pre-processing and wafer bonding step itself. These investigations ultimately allowed optimized wafer processing, improved process control and reliability investigation.