Study on the performance of silver paste sintered sealing joints for hermetic packaging

The traditional hermetic packaging methods, which require high temperatures and high voltages, would have adverse effects on electronics devices. Based on current-assisted sintering technology, we proposed a new hermetic packaging method using silver paste. Comparing the microstructure of the joints sintered with different currents, we found that with the increasing sintering current from 4.7 kA to 5.3 kA, the density of the joint increases, which improves the hermeticity and bonding strength of the joints. The results of thermal cycling tests showed that the sealing joints sintered at 4.7 kA with larger porosity are more prone to fail because pores tend to be sources of defects under thermal cycling. After 250 ℃ high thermal storage, there is the coarsening of the pores and the delamination near the Ag/Au interface, degrading the sealing performance of the sintered joint. Besides, the sealing joints sintered at 5.3 kA exhibit superior reliability when exposed to high temperatures.