The purpose of this study is that the effects of surface mount technology (SMT) assembly process on the product lifetime of fine-pitch printed circuit boards (PCBs) were investigated under biased highly accelerated stress testing (HAST).,SMT assembly from a semiconductor SMT assembly process was replicated to test PCBs under the same conditions as SMT-assembled PCBs. The median lives µ and standard deviation s of the test PCBs were calculated from the log-normal distribution. The failure analysis of current leakages was conducted by the focused ion beam, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Using the inverse power law and modified Peck-H’s relationship, the PCB lives at accelerated (by SMT assembly stress) and user conditions were calculated.,The failure analysis demonstrated that SiO2 and BaSO4 fillers added for stiffening organic materials promote current leakage failure. Therefore, the hydrophobicity of these fillers is believed to be necessary to suppress the current leakage failure under biased HAST. The inverse power law model indicates that the acceleration life model with SMT assembly stress can be given as follows: L(V) = 271.9(S)−0.5031. From modified Peck-H’s relationship, after the third SMT assembly, the time required to attain 0.96 per cent failures at 35°C/60 per cent RH/1.9 V and 130°C/85 per cent RH/3.5 V are 129 y and 69.5 h, respectively. The biased HAST at 130°C/85 per cent/3.5 V after the third SMT assembly for 69.5 h on 238 samples could be recommended as an early quality-monitoring procedure.,In the future, the failure modes in an early stage of a bathtub should be analyzed and the life prediction model should be studied accordingly.,Through this study, the lifetime prediction model and early quality-monitoring procedure for organic substrates because of SMT assembly stress were obtained.

中文翻译：

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SMT 组装对有机基板寿命降低的影响

本研究的目的是在偏置高加速应力测试 (HAST) 下研究表面贴装技术 (SMT) 组装工艺对细间距印刷电路板 (PCB) 产品寿命的影响。, 来自半导体的 SMT 组装复制 SMT 组装过程以在与 SMT 组装 PCB 相同的条件下测试 PCB。测试 PCB 的中值寿命 µ 和标准偏差 s 由对数正态分布计算得出。通过聚焦离子束、扫描电子显微镜和能量色散X射线光谱仪对电流泄漏进行故障分析。使用逆幂律和修正的 Peck-H 关系，PCB 寿命在加速（由 SMT 组装应力）和用户条件下计算。失效分析表明，为加强有机材料而添加的 SiO2 和 BaSO4 填料会促进漏电失效。因此，这些填料的疏水性被认为是抑制偏置 HAST 下电流泄漏故障所必需的。逆幂律模型表明，具有 SMT 装配应力的加速寿命模型可以给出如下： L(V) = 271.9(S)-0.5031。根据修正的 Peck-H 关系，在第三次 SMT 组装后，在 35°C/60% RH/1.9 V 和 130°C/85% RH/3.5 V 下达到 0.96% 失效所需的时间为 129 y 和分别为 69.5 小时。在对 238 个样品进行第三次 SMT 组装 69.5 小时后，130°C/85%/3.5 V 的偏置 HAST 可被推荐作为早期质量监控程序。,在未来，