Ag/Sn/Cu 瞬时液相连接过程中界面反应的研究

Transient liquid phase (TLP) bonding is a promising electronic packaging technology to satisfy the needs of operating at high temperatures due to the increasing power density of power electronic devices. More and more power chips are finished with Ni/Ag metallization, while the top metal is Cu in direct bonded copper. However, interfacial reactions in Cu/Sn/Ag system were rarely studied. In order to explore the intermetallic reaction kinetics between solder and substrate in Cu/Sn/Ag system, this study investigated the effect of different reflow temperatures (250–350 °C) and time (30–960 s) on the microstructure evolution of the interfaces of three different TLP systems (Cu/Sn, Ag/Sn and Cu/Sn/Ag), and the growth kinetics of two intermetallic compounds (IMCs) Cu 6 Sn 5 and Ag 3 Sn. The results indicate that the activation energy of Cu 6 Sn 5 in Cu/Sn/Ag TLP increases by 42.8% compared to Cu/Sn TLP, and the activation energy of Ag 3 Sn increases by 34.1% compared to Ag/Sn TLP. During the solid–liquid process of Ag/Sn/Cu TLP, Ag atoms from the Ag substrate side will cross through the molten Sn layer to form Ag 3 Sn on the surface of Cu 6 Sn 5 IMCs on the Cu substrate side. Meanwhile, Cu atoms from the Cu substrate side will reach Ag substrate side to form Cu 6 Sn 5 on the surface of Ag 3 Sn IMCs. Heterogeneous IMCs at the interface hinder the grain boundary/melting channel for the diffusion of substrate atoms, increasing the activation energy and inhibiting their growth.