In typical service environments, high current densities pass through the interconnection leads of solder joints. The electromigration reliability of solder joints is thus of great significance. The microstructure, crystal orientation, and electromigration reliability of Sn-0.3Ag-0.7Cu-1.6Bi-0.2In solder were studied in this work. The results showed that the melting point of Sn-0.3Ag-0.7Cu-1.6Bi-0.2In solder is 212.3°C, with good wettability. The addition of Bi and In reduced the melting point and undercooling of the solder, with improved solder wettability. Compared with Sn-3.0Ag-0.5Cu solder, the microstructure of the remelted solder was well distributed with fine grains. Compounds formed by substituting Sn atoms with In atoms. Among the linear solder joints, those made of Sn-0.3Ag-0.7Cu-1.6Bi-0.2In showed easier formation of polycrystalline structure, and the c-axis orientation of β-Sn grains was more disordered. The addition of Bi and In to form Sn-0.3Ag-0.7Cu-1.6Bi-0.2In affected the formation and growth of intermetallic compounds and improved the electromigration reliability of solder joints.

在典型的服务环境中，高电流密度会通过焊点的互连引线。因此，焊点的电迁移可靠性非常重要。本文研究了Sn-0.3Ag-0.7Cu-1.6Bi-0.2In焊料的微观结构，晶体取向和电迁移可靠性。结果表明，Sn-0.3Ag-0.7Cu-1.6Bi-0.2In焊料的熔点为212.3°C，润湿性良好。Bi和In的添加降低了焊料的熔点和过冷，并改善了焊料的润湿性。与Sn-3.0Ag-0.5Cu焊料相比，重熔焊料的微观结构分布均匀，晶粒细密。用Sn原子取代Sn原子形成的化合物。在线性焊点中，由Sn-0.3Ag-0.7Cu-1.6Bi-0制成的焊点。β-Sn晶粒的c轴取向更加无序。Bi和In的添加形成Sn-0.3Ag-0.7Cu-1.6Bi-0.2In影响了金属间化合物的形成和生长，并提高了焊点的电迁移可靠性。