Current-assisted low-temperature silver sinter bonding to silicon carbide by utilizing ion migration

Sinter bonding using fine metal particles has attracted significant attention as a promising technology for next- generation power devices. However, achieving high-strength joints between semiconductor materials and metal substrates remains challenging due to the low interfacial bonding ratios, leading to interfacial fractures that weaken the joint. Herein, we demonstrate a current-assisted low-temperature Ag sinter bonding process for SiC, utilizing ion migration within the bonding layer. The process significantly improved the joint strength by enhancing the interfacial bonding properties via Ag precipitation on the SiC surface. The precipitation, facilitated by the current-driven migration of Ag ions derived from the decomposition of compounds, effectively increased the density and interfacial bonding ratio of the sintered Ag layer, thereby mitigating interfacial fracture. Based on these findings, we successfully achieved current-assisted sinter bonding, notably at room temperature. Furthermore, the current-driven migration of the generated Ag ions was sufficiently induced even with a minimal amount of Ag compounds. Accordingly, the joint properties were further enhanced by suppressing localized vulnerability in the sintered Ag layer through the optimization of the Ag2O mixture ratio in the bonding paste. This current-assisted process plays a crucial role in achieving reliable low-temperature sinter bonding, essential for advanced electronics packaging.