论文部分内容阅读
对热循环条件下SnAgCu/Cu焊点的热力疲劳行为进行了研究。基于热循环条件下实际倒装焊点的位移分析,设计了单焊点试样及其热力耦合加载装置。利用电阻应变测量法研究了–40~125℃热循环条件下焊点的变形行为。以电阻变化率为损伤参量,确定了焊点的损伤演变规律以及焊点热疲劳寿命。基于此,采用基于应变的Coffin-Manson模型确定了焊点寿命与非弹性应变之间的关系。结果表明焊点随加载应变范围的增大而出现加速破坏。最后,对热循环过程中SnAgCu/Cu焊点的微观组织演变进行了扫描电镜观察分析,旨在进一步揭示焊点失效的本质。
The thermal fatigue behavior of SnAgCu / Cu solder joints under thermal cycling was studied. Based on the displacement analysis of actual flip-chip solder joints under thermal cycling conditions, a single solder joint sample and its thermal coupling device were designed. Deformation behavior of solder joints under thermal cycling from -40 ℃ to 125 ℃ was investigated by resistance strain measurement. Taking the rate of resistance change as the damage parameter, the damage evolution law of the solder joint and the thermal fatigue life of the solder joint were determined. Based on this, the strain-dependent Coffin-Manson model was used to determine the relationship between solder joint life and inelastic strain. The results show that the welding spot accelerates with the increase of the loading strain range. Finally, the microstructure evolution of SnAgCu / Cu solder joints during the thermal cycling was observed by scanning electron microscopy to further reveal the nature of solder joint failure.