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Fe Ni合金与无铅焊料反应速率低,生成的金属间化合物(IMC)较薄,有望作为圆片级封装(WLP)凸点下金属(UBM)层材料。对两种Fe Ni UBM以及一种Cu UBM圆片级封装样品进行回流、湿热以及预处理实验,并通过推球的方法,对其焊点进行剪切测试。通过断面与截面分析,研究其在不同处理条件下的金属间化合物生长情况,分析其断裂模式。结果表明,Fe Ni UBM焊点剪切力高于Cu UBM。Fe47Ni UBM与焊料反应生成的金属间化合物较薄,对于剪切力影响较小,而Fe64Ni UBM与焊料反应生成离散的Cu Ni Sn金属间化合物,对于其焊点强度有提高作用,Cu UBM与焊料反应生成较厚的金属间化合物,会明显降低焊点的剪切力。断面分析表明,Cu UBM会随焊球发生断裂,其强度明显小于Fe Ni UBM。
Fe Ni alloy has low reaction rate with lead-free solder and low IMC, which is expected to be the material of WLP bump metal (UBM). The Fe Ni UBM and a Cu UBM wafer-level package samples were tested for reflow, heat and humidity, and pretreatment. The solder joints were sheared and tested by a push ball method. Through the section and section analysis, the growth of intermetallic compounds under different treatment conditions was studied, and the fracture mode was analyzed. The results show that the shear force of Fe Ni UBM solder joint is higher than that of Cu UBM. Fe47Ni UBM and the solder reaction of the intermetallic compounds thin, little impact on the shear force, and Fe64Ni UBM react with the solder to generate discrete Cu Ni Sn intermetallic compounds, for its solder strength, Cu UBM and solder Reaction to generate thick intermetallic compounds, will significantly reduce the shear force of solder joints. The cross-section analysis shows that Cu UBM will fracture with the solder ball and its strength is obviously less than Fe Ni UBM.