Wafer level hermetic package and device testing of a SOI-MEMS switch for biomedical applications

We have designed a wafer level chip scale package for a bi-stable SOI-MEMS dc switch using a silicon-glass hermetic seal with through the lid feedthroughs. Bonded at 365 °C, 230 V and 250 kg, they pass the fine/gross leak test after thermal cycling and mechanical shock/vibration according to MIL-STD-833, fulfilling the requirements for biomedical applications. The measured shear strength is 114 ± 26 N in correspondence with the theoretically expected 100 N. Ruthenium microcontacts are a factor of 100 more robust than gold microcontacts, being stable over 106 cycles measured in a N2 atmosphere inside the package presented here. Future work will include a more extensive bond quality assessment and continued microcontact reliability measurements.