An investigation on thermal reliability of underfilled PBGA solder joints
An investigation on thermal reliability of underfilled PBGA solder joints
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底部填充PBGA焊点热可靠性研究
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
W. Kempe
中科院分区：
文献类型：
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作者：
Zhang Liji;Wang Li;Xie Xiaoming;W. Kempe
介绍了两组 PBGA 样品（带/不带底部填充）在 -40/spl square/-125/spl square/ 范围内的热冲击时的失效机制以及失效周期。实验表明，没有底部填充的样品中的焊球在500次循环后出现裂纹，而底部填充的样品在2700次循环后也没有发现裂纹。然而，芯片附着层在 500 次循环后分层，并且长时间循环后底部填充样品中的 PCB 破裂。 C-SAM 用于研究底部填充样品中的分层。本文讨论了BGA元件与PCB之间的CTE不匹配引起的高度集中的应力应变、粗化晶粒以及回流和热循环过程中形成的两种金属间化合物(Ni/sub 3/Sn/sub 2//NiSn/sub 4/)及其对焊点可靠性的影响。本文还介绍了裂纹的萌生及其扩展。通过染料渗透测试，作者揭示了焊球阵列中微裂纹的分布情况。此外，本文还给出了仿真结果，进一步验证了其结论。
The failure mechanism, as well as cycles to failure, of two groups of PBGA samples (with/without underfill) for thermal shock in the range of -40/spl square/-125/spl square/ were presented. The experiment shows that the solder ball in the samples without underfill cracked after 500 times cycle, while no crack was found in the underfilled samples even after 2700 cycles. However, the die attach layer delaminated after 500 cycles and the PCB cracked in the underfilled samples after long time cycling. C-SAM is employed to investigate the delamination in the underfilled samples. Highly concentrated stress-strain induced by the CTE mismatch between the BGA component and the PCB, coarsened grain and two kinds of intermetallic compounds (Ni/sub 3/Sn/sub 2//NiSn/sub 4/) which formed during reflow and thermal cycling and their impact on the reliability of solder joints are discussed in this paper. The initiation of the crack and its propagation are also presented in this paper. By means of dye penetrant test, the authors reveal the distribution of microcracks in the solder ball array. In addition, this paper includes results of simulation, which further verified its conclusions.