Low melting temperature solders are becoming a hot topic in Pb-free solder studies. Among these solders, SnBi has attracted more attention because it can not only reduce the energy for reflow, but more importantly, increase the reliability of joints by minimizing warpage. In this study, the board-level reliability of the assembly of BGA components was investigated. Three types of assemblies are compared: mixed (hybrid) Sn-Bi/SAC305 assembly, which is made by soldering BGAs with SAC305 solder balls using eutectic SnBi solder pastes so that the low reflow temperature avoids the SAC305 solder joints from being molten; homogeneous eutectic SnBi assembly, which is made with solder balls and pastes that are both eutectic Sn-Bi; and homogenous SAC305 assembly as a control group. An accelerated thermal cycling test shows that homogeneous eutectic SnBi assembly exhibits the best cycling reliability while the mixed assembly has the shortest fatigue life. The failure mechanism of the mixed assembly is also different from the other two types. Based on the experimental fatigue life results, the parameters of constitutive equation of eutectic SnBi are calculated to evaluate the fatigue life of the solder joints. The study shows the better thermal cycling reliability of eutectic SnBi assembly and help predict the fatigue life of different assemblies.

低熔点焊料正成为无铅焊料研究中的热门话题。在这些焊料中，Sn Bi不仅引起减少回流的能量，而且更重要的是，通过最大程度地减少翘曲来提高接头的可靠性，因此引起了更多关注。在这项研究中，对BGA组件组装的板级可靠性进行了研究。比较了三种类型的组件：混合（混合）Sn-Bi / SAC305组件，该组件是通过使用共晶Sn Bi焊膏将BGA与SAC305焊球焊接而制成的，这样低的回流温度可避免SAC305焊点熔化。均匀共晶锡Bi组件，由共晶Sn-Bi的焊球和焊膏制成；均质的SAC305组件作为对照组。加速热循环试验表明，均匀的共晶锡铋组件表现出最佳的循环可靠性，​​而混合组件的疲劳寿命最短。混合组件的故障机理也不同于其他两种类型。根据实验疲劳寿命结果，计算出共晶锡铋的本构方程参数，以评价焊点的疲劳寿命。研究表明，共晶锡铋组件具有更好的热循环可靠性，有助于预测不同组件的疲劳寿命。