Long-term evaluation of hermetically glass frit sealed silicon to Pyrex wafers with feedthroughs

The reliability of bonding silicon to Pyrex wafers using a reflowed glass frit seal is examined in this paper. The Pyrex wafers have metal feedthroughs, which are used to actuate and capacitively sense a single-crystal, silicon resonator. Long-term, high-temperature storage conditions for chips with and without getters are examined. The reflowed glass seal is demonstrated to be hermetic for years at high temperature using both diaphragm deflection and the Q and frequency of resonators as a vacuum indicator. The use of a thin film getter is found to eliminate Q hysteresis due to gas desorption and adsorption, observed in other resonators studies.