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采用热疲劳试验分析了表面封装焊点的可靠性。讨论了不同的元器件及基片镀层工艺对焊点可靠性的影响，初步探讨了热疲劳过程中位错亚结构的变化及焊点的失效机理。结果表明：金属间化合物对焊点失效有重要影响．镀Ａｕ焊点热疲劳裂纹萌生于ＡｕＳｎ４金属间化合物并在其中扩展，镀Ｎｉ／Ａｕ焊点热疲劳过程中位错在ＡｕＳｎ４粒子处塞积，引起ＡｕＳｎ４／β－Ｓｎ界面应力集中，导致热疲劳裂纹沿ＡｕＳｎ４／β－Ｓｎ界面萌生，萌生后的裂纹在β－Ｓｎ相中扩展，ＴＥＭ观察也证明β－Ｓｎ相中位错密度较高。
The thermal fatigue test is used to analyze the reliability of surface mount solder joints. The influence of different components and substrate plating process on the reliability of the solder joint is discussed. The change of the dislocation substructure and the failure mechanism of the solder joint during thermal fatigue are discussed. The results show that the intermetallic compounds have an important influence on the solder joint failure. The thermal fatigue crack of the Au-plated solder joint sprouted and expanded in the AuSn4 intermetallic compound. During the thermal fatigue of the Ni / Au solder joint, the dislocations were plugged in the AuSn4 particles, causing the stress concentration in the AuSn4 / β-Sn interface, resulting in thermal fatigue The crack initiated along the AuSn4 / β-Sn interface, and the cracks after the initiation were expanded in the β-Sn phase. The TEM observation also showed that the dislocation density was higher in the β-Sn phase.