Rapid Formation of High-Strength Sintered Silver Joints with High Reliability

High operating temperatures of wide bandgap (WBG) devices can lead to the remelting of conventional tin-based solders, resulting in serious reliability problems. In this context, silver sintering technology, providing sintered silver joints with excellent electrical and thermal conductivity and high-temperature stability, has been intensively developed in recent years. Although sintered silver joints are formed at low temperatures, they demonstrate a high melting point close to bulk silver, allowing them to operate steadily at the high temperatures required for WBG devices. In this study, we improved the sintering performance of micron-silver paste by introducing appropriate sintering aids to achieve rapid sintering. The addition of suitable organic anhydrides/acids, such as malic acid, could effectively improve the sintering performance of micron-silver paste and form high-strength sintered silver joints (59.38 MPa) in a short sintering time (2 min). In addition, the pre-drying form greatly affected the final microstructure of sintered silver joints, and an open-face convective drying (OVectDry) form can effectively prevent the formation of voids in the sintered silver joints. Finally, we systematically investigated the reliability of the sintered silver joints and the evolution of the microstructure of the sintered silver joints during different reliability tests, such as high-temperature storage test (HST), temperature cycling test (TCT), thermal shock test (TST). We think that the introduction of sintering aids and the improved sintering process are effective ways to improve the sintering performance of micron-silver paste, and this work could draw more attention of researchers and engineers to sintering aids and sintering process, which can promote the development of silver sintering technology.