热循环条件下Sn基钎料接头电迁移行为研究

Study of electromigration behavior on Sn-based solder joints under thermal cycling

通过电迁移和热疲劳循环实验,研究了热循环和高电流密度耦合作用下Sn58Bi和Sn3.0Ag0.5Cu钎料焊接接头的失效形式。实验结果表明,在通电和高低温冲击的耦合作用下,两种钎料接头的失效都发生在升温阶段。热循环导致接头内部裂纹的萌生和扩展,导致局部电流密度持续增大,加速了电迁移的发生,最终导致焊点失效。在热电耦合作用下,Sn58Bi钎料接头的使用寿命要长于Sn3.0Ag0.5Cu钎料接头的使用寿命。

By tests of electromigration and thermal fatigue cycle, the failure mechanisms of solder joints of Sn58Bi and Sn3.0Ag0.5Cu were studied under the coupling effect of thermal cycle and high current density. Test results indicate, under the coupling conditions, the failures both occur at heating stage; thermal cycling contributes to cracks nucleation and propagation so as to raise the current density on portions of solder joints, which further accelerates electromigration and induces final failure appearance. Sn58Bi solder joint has a longer life than that of Sn3.0Ag0.5Cu under coupling circumstance.