锌对共晶锡铋合金的电迁移可靠性的影响

本文选取了应用最为广泛的无铅钎料之一的共晶锡铋合金进行研究,对其进行锌的掺杂,以期透彻的了解锌对无铅钎料在电迁移作用下的行为。研究结果显示,在钎焊结束之后,电流加载之前,掺入的锌会通过促进合金晶粒粗化在一定程度上降低焊点的抗拉强度。但是对焊点进行电流密度为104 A/cm2的电流加载100h后,锌的掺入可以避免锡铋合金中锡相与铋相晶粒之间形成缝隙,从而对焊点的可靠性有显著的提升。

Effect of Zn Element on Electromigration Reliability of Eutectic SnBi Alloy

In order to thoroughly understand the effect of Zn on the behavior of lead-free solder under electromigra- tion, we chose eutectic SnBi alloy, one of the mostly used lead-free solders, as our study item. The results indicate that at as-reflowed state, Zn doping will aggravate the grain coarsening process, which would degrade the mechani- cal strength of solder joint to a certain degree. However, when the samples were stressed under the current density of 104 A/cmz up to 100 hours, Zn doping could prevent the Sn phase and Bi phase from separating, which will en- hance the mechanical strength of solder joint significantly.