电迁移对低银无铅微尺度焊点力学行为的影响

Influence of electromigration on mechanical behaviors of low-Ag lead-free microscale solder joints

研究了电迁移条件下不同电流密度（0.63～1.0×10^4A/cm^2）和通电时间（0～48 h）对低银无铅Sn-Ag-Cu微尺度焊点的拉伸力学行为的影响.结果表明,电迁移导致了低银无铅微尺度焊点的抗拉强度显著降低,并且随着电流密度的增加或通电时间的延长,焊点的抗拉强度均呈下降趋势;同时电迁移还导致焊点的拉伸断裂模式发生明显变化,在经历高电流密度或长时间通电的电迁移后,焊点在服役条件下会发生由韧性断裂向脆性断裂的转变.此外含银量高的微尺度焊点的抗电迁移性能更强.

The influence of electromigration on tensile mechanical behaviors of low-Ag lead-free microscale solder joints was characterized under different current densities( 0. 63 ~ 1. 0× 104 A / cm2) and holding time( 0 ~ 48 hours). The experiment results show that tensile strength of low-Ag lead-free microscale solder joints is obviously degraded by electromigration,and the increase in both current density and holding time leads to a decrease of tensile strength of the microscale solder joints. In addition,electromigration induces fracture mode transition phenomena at the cathode interface of the solder joints,that is,from ductile fracture in the solder joints without electromigration to brittle fracture for those after strong electromigration using high current density and long holding time. Also,higher Ag content in the low-Ag lead-free microscale solder joints will improve electromigration resistance.