Abstract Properly assessing the underlying physics of failure is critical in predicting the long term reliability of electronic packages in their intended field applications, yet traditional reliability demonstration methods are complicated by time and cost considerations as well as deterministic inadequacies when considering thermomechanical failures. In this work, an alternative reliability testing apparatus and associated protocol were utilized to provide clarity and insight to solder fatigue mechanisms at the device scale; targeting rapid testing times with minimal cost while preserving fatigue life prediction accuracy. A test stand was developed to allow for bi-directional application of shear stress at elevated steady-state temperatures. Utilizing the mechanical force of springs to apply shear loads to solder interconnects within the devices, the reliability of a given device to withstand repeated cycling was studied using in situ resistance monitoring techniques to detect the number of cycles-to-failure (CTF) based on a 30% resistance increase criterion. A mathematical method for quantifying the plastic work density (amount of damage) sustained by the solder interconnects prior to failure was developed relying on the relationship between Hooke's Law for springs and damage deflection to accurately assess the mechanical strength of tested devices.

中文翻译：

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等温焊料互连中的加速机械低周疲劳

摘要 正确评估故障的基本物理原理对于预测电子封装在预期现场应用中的长期可靠性至关重要，但传统的可靠性演示方法因时间和成本考虑以及在考虑热机械故障时确定性的不足而变得复杂。在这项工作中，使用了替代可靠性测试设备和相关协议，以提供对器件规模的焊料疲劳机制的清晰和洞察力；以最低的成本实现快速测试，同时保持疲劳寿命预测的准确性。开发了一个测试台，以允许在升高的稳态温度下双向应用剪切应力。利用弹簧的机械力对器件内的焊接互连施加剪切载荷，使用原位电阻监测技术来研究给定设备承受重复循环的可靠性，以检测基于 30% 电阻增加标准的失效循环数 (CTF)。开发了一种用于量化失效前焊料互连承受的塑性工作密度（损坏量）的数学方法，该方法依赖于弹簧的胡克定律与损坏挠度之间的关系，以准确评估测试设备的机械强度。