組織変化を考慮したBGAパッケージはんだ接合部の熱疲労寿命予測

抄録

A method to predict thermal fatigue life of BGA solder joint in semiconductor packages with consideration of microstructural coarsening was proposed, and thermal fatigue life was predicted by using the method. In this study, dispersion strengthening type creep constitutive equation that depends on radius of dispersoids was adopted for finite element analysis of the thermal fatigue of solder alloy in a BGA type semiconductor package. As a result, the thermal fatigue life of BGA solder joint with consideration of microstructural coarsening of solder was decreased compared to that with the use of the property of the initial microstructure, since the creep strain energy density range was continuously increased due to the growth of the dispersoids during thermal cycles. In particular, the decrease in the life in the field condition was remarkable, and the life was decreased by 54% compared to the case without the microstructural considering. Thus, consideration of microstructural coarsening is necessary for thermal fatigue life prediction of BGA solder joint.