LAUSR

Abstract Hermetic sealing devices are produced with Au-20Sn solder at different oxygen content levels to study the reliability of the seal joints. Cross section of Au-20Sn solder joints processed with different oxygen content were examined by SEM, which shows that the microstructure displayed an obvious deterioration with the increase of oxygen content. It was found that bonding at 16 ppm oxygen content level, an uniform bonding interface with void-free was obtained with good hermeticity. However, when the oxygen content reached 55 ppm, voids and cracks were generated along the seal joint and the helium leak rate was higher than 5 × 10−8 atm cm3/s, which is the rejected limit value of MIL-STD-883 K. According to the reliability test results, we believe that the hermeticity deterioration is attributed to voids and cracks with the extension of aging time. In addition, samples with poor hermeticity were analyzed to know the failure mechanism of the seal joints and the feasible methods were proposed for improving hermeticity.