Electromigration performance of Pb-free solder joints in terms of solder composition and joining path
Electromigration performance of Pb-free solder joints in terms of solder composition and joining path
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DOI：
10.1007/s11837-010-0104-9
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发表时间：
2010-07
期刊：
影响因子：
2.6
通讯作者：
S. Seo;Sung K. Kang;M. Cho;Hyuck-Mo Lee
中科院分区：
文献类型：
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作者：
S. Seo;Sung K. Kang;M. Cho;Hyuck-Mo Lee
研究了无铅焊点在凸点金属化(UBM)下的电迁移(EM)性能，包括焊料成分(Sn0.5Cuvs.Sn1.8Ag)和连接路径。在Ni(P)/焊料/铜双面焊点中，焊料成分和连接路径对焊点组织和界面金属间化合物(IMC)层有显著影响。与连接路径无关，Sn-0.5Cu接头的回流组织由细小的柱状晶组成，在两个UBM界面处都有较薄的IMC层，而在先与Ni(P)UBM连接时，有少量大颗粒的小角度晶界，具有较厚的IMC层，而在首先与CuUBM连接时，有少数60°孪晶，具有较薄的IMC层。在150°C大电流密度下的电磁应力测试表明，与锡-0.5Cu接头相比，锡-1.8Ag接头具有更高的寿命。此外，在所考察的四组焊点中，先在Ni(P)UBM上回流的锡-1.8Ag焊点的电磁寿命最长。
The electromigration (EM) performance of Pb-free solder joints is investigated in terms of solder composition (Sn-0.5Cu vs. Sn-1.8Ag) and joining path to Cu vs. Ni(P) under bump metallization (UBM). In the double-sided joints of Ni(P)/solder/Cu, the micro-structure of solder joints and the interfacial intermetallic compound (IMC) layers are significantly affected by solder composition and joining path. The as-reflowed microstructure of Sn-0.5Cu joints consists of small columnar grains with thin IMC layers at both UBM interfaces, independent of the joining path, while Sn-1.8Ag joints have a few large grains of low-angle grain boundaries with thick IMC layers when joined first to Ni(P) UBM, but a few 60° twins with thin IMC layers when joined first to Cu UBM. The EM stressing under high current densities at 150°C reveals that Sn-1.8Ag joints have a superior lifetime compared to Sn-0.5Cu joints. In addition, the EM lifetime of Sn-1.8Ag joints reflowed first on Ni(P) UBM is the longest among four groups of the solder joints examined.