Evaluation of material nonlinearity of Cu/Sn IMCs based on FEA of shear test using copper-solder joints
Evaluation of material nonlinearity of Cu/Sn IMCs based on FEA of shear test using copper-solder joints
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DOI：
10.2207/qjjws.38.429
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
K. Kurosawa;K. Ohguchi;K. Fukuchi;A. Takita
中科院分区：
文献类型：
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作者：
K. Kurosawa;K. Ohguchi;K. Fukuchi;A. Takita
超高密度封装焊点的有限元分析（FEA）必须准确了解Cu/Sn金属间化合物（IMC）：Cu 3 Sn和Cu 6 Sn 5的变形特性。因此，作者在以前的工作中提出了一种方法来估计这些IMC的拉伸特性。该方法提供了两个新的发现。一个是Cu/Sn IMC的断裂伸长率约为1.4%。二是Cu/Sn金属间化合物的应力-应变关系呈非线性。由于Cu/Sn金属间化合物长期以来被认为是弹性材料，后一种发现应该以某种方式得到验证艾德。然后，在这项研究中，我们进行了有限元分析，模拟剪切试验使用的铜焊点试样，其焊点有铜/锡IMC层。以两种不同的方式进行加载条件的FEA;即，采用弹性本构模型和弹塑性本构模型描述了不同加载条件下金属间化合物的变形行为。在与有限元分析相同的加载条件下进行了实际剪切试验。通过与实际测试结果的比较，我们讨论了Cu/Sn金属间化合物材料非线性的存在与否。结果表明，Cu/Sn金属间化合物具有材料非线性。
Finite-element analysis (FEA) of solder joints for ultrahigh-density packages must be conducted with an accurate understanding of the deformation characteristics of the Cu/Sn intermetallic compounds (IMCs): Cu 3 Sn and Cu 6 Sn 5 . Therefore, the authors proposed a method to estimate the tensile characteristics of these IMCs in the previous work. The method provided two new findings. One is that the breaking elongation of the Cu/Sn IMCs is approximately 1.4%. The other is that the stress-strain relation of the Cu/Sn IMCs shows nonlinearity. Since the Cu/Sn IMCs have been regarded as elastic materials for a long time, the latter finding should be verified in some way. Then, in this study, we conducted FEAs which simulate the shear tests using the copper-solder joint specimen whose solder joint has the Cu/Sn IMCs layers. The FEA for a loading condition was conducted in two different ways; i.e., two different constitutive models of an elastic model and an elastic-plastic model were employed to describe the deformation behavior of the IMCs for a loading condition. Actual shear tests were also conducted in the same loading conditions as the FEAs. Comparing the FEAs with the actual tests, we discussed the presence or absence of the material nonlinearity of the Cu/Sn IMCs. The result suggested that the Cu/Sn IMCs should have material nonlinearity.