HALT環境を考慮した銅-ハンダ接合試験片による二軸強度試験

抄録

Recently, HALT (Highly accelerated limit test) is used for an accelerated test of electronic products to evaluate the reliability of the products. Solder joints are important parts in electronic devices. Therefore, clarification of the deformation behavior and fracture of the solder joints due to HALT is required. In this study, a series of biaxial loading tests using copper-solder joint specimens is carried out in order to reproduce the deformation and failure of solder joint in HALT condition. The authors are trying to construct a method for fatigue life estimation based on the biaxial ratcheting test of solder joints considering HALT. In this study, both the thermal cyclic and mechanical vibration load were simulated by the cyclic torsion load and small cyclic axial load in the biaxial ratcheting test. As a result, the ratcheting strain increment greatly increased with increase in the superposed stress. In addition, the vibration load increases the ratcheting strain. These results coincide with the tendency for solder joint to fracture earlier in the HALT condition. Moreover, linear relationship between the ratcheting strain rate and fatigue life was obtained by the single logarithmic plot. These results suggest that the ratcheting strain rate may be design parameter for estimating fatigue life of solder.