In this work, the effects of extreme thermal fluctuations on the reliability of solder joints were investigated. For this purpose, the solder joints in insulated-gate bipolar transistor (IGBT) devices were exposed to the conventional thermal cycling and the thermal shock cycling (TSC) tests. The finite element method (FEM) simulation results indicated that the accumulated creep energy in solder layer is much higher under the TSC process. Moreover, the stress triaxiality, as the indicator of damage initiation, is more concentrated in the TSC-exposed sample. It is believed that the higher heating and cooling rates along with the higher peak temperatures lead to the damage susceptibility of solder joints under TSC process. The experimental results confirm that the void formation and growth significantly increases in the TSC-exposed sample, which is consistent with the simulation outcomes. Moreover, the shear test reveals that the ultimate strength of sample under the thermal shocking severely decreases which is due to the void growth and the intensified elemental heterogeneity.

中文翻译：

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极端热波动下电子设备中焊点的可靠性评估

在这项工作中，研究了极端温度波动对焊点可靠性的影响。为此，绝缘栅双极晶体管（IGBT）器件中的焊点要经受常规的热循环和热冲击循环（TSC）测试。有限元方法（FEM）的仿真结果表明，在TSC工艺下，焊料层中的累积蠕变能量要高得多。此外，应力三轴性作为破坏开始的指标，更集中在暴露于TSC的样品中。可以认为，较高的加热和冷却速率以及较高的峰值温度会导致TSC工艺下焊点的易损性。实验结果证实，暴露于TSC的样品中空隙的形成和生长显着增加，与仿真结果一致。此外，剪切试验表明，由于空洞的增长和元素异质性的增强，样品在热冲击下的极限强度会大大降低。