Polarity effect of electromigration on kinetics of intermetallic compound formation in Pb-free solder V-groove samples
Polarity effect of electromigration on kinetics of intermetallic compound formation in Pb-free solder V-groove samples
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DOI：
10.1063/1.1861151
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发表时间：
2005-03-15
影响因子：
3.2
通讯作者：
Tu, KN
中科院分区：
文献类型：
--
作者：
Gan, H;Tu, KN
金属间化合物（IMC）的形成对微电子互连的可靠性至关重要，特别是对于倒装芯片焊点。在这篇文章中，我们研究的极性效应的电迁移的IMC形成的动力学在阳极和阴极的焊料V形槽样品。我们使用V型槽焊料线样品，宽度为100 μ m，长度为500 - 700 μ m，研究在不同的电流密度和温度设置下，Cu电极和Sn-3.8Ag-0.7Cu（wt %）焊料之间的界面IMC生长。电流密度在10（3）至10（4）A/cm（2）的范围内，温度设置为120、150和180 ℃。虽然相同类型的IMC，Cu6Sn5和Cu3Sn，形成在焊料/Cu界面独立的电流的通道，IMC层的生长已被增强的电流在阳极和抑制在阴极，与无电流的情况下相比。我们提出了一个动力学模型，在样品中的Cu的质量传输的基础上，来解释在阳极和阴极的IMC的生长速率。IMC在阳极的生长遵循抛物线生长规律，我们认为IMC中诱导的背应力起着重要的作用。该模型与实验数据吻合较好。讨论了电流作用下化学力和电场力对IMC生长的影响，以及二者的联合作用对IMC生长的影响。(C)2005年美国物理学会。
Intermetallic compound (IMC) formation is critical for the reliability of microelectronic interconnections, especially for flip chip solder joints. In this article, we investigate the polarity effect of electromigration on kinetics of IMC formation at the anode and the cathode in solder V-groove samples. We use V-groove solder line samples, with width of 100 mu m and length of 500-700 mu m, to study interfacial IMC growth between Cu electrodes and Sn-3.8Ag-0.7Cu (in wt %) solder under different current density and temperature settings. The current densities are in the range of 10(3) to 10(4) A/cm(2) and the temperature settings are 120, 150, and 180 degrees C. While the same types of IMCs, Cu6Sn5 and Cu3Sn, form at the solder/Cu interfaces independent of the passage of electric current, the growth of the IMC layer has been enhanced by electric current at the anode and inhibited at the cathode, in comparison with the no-current case. We present a kinetic model, based on the Cu mass transport in the sample, to explain the growth rate of IMC at the anode and cathode. The growth of IMC at the anode follows a parabolic growth rule, and we propose that the back stress induced in the IMC plays a significant role. The model is in good agreement with our experimental data. We then discuss the influence of both chemical force and electrical force, and their combined effect on the IMC growth with electric current. (C) 2005 American Institute of Physics.