Thermal Fatigue Life Prediction Of Solder Joints Using Stress Analysis

Abstract

The fatigue life prediction of solder joints has become one of the most important research areas in the development of reliable electronic components. In this study. elastic-creep stress analysis proposed in previous papers was carried out for the solder joints of a recently developed LSI package (ball grid array package). The results of fatigue life estimation agreed well with those of the actual thermal cycle tests (TCT). The acceleration factor, which serves as the quantitative correlat,ion between the TCT condition and field conditions, was determined from the analytical results using the Coffin-Manson equation. It was clear that temperature hold-time under field conditions had a noticeable effect on the fatigue life. Thus, careful consideration of field conditions is essential in the reliability design. From the results of this study it was concluded that the fatigue life estimation of solder joints based on the present method is satisfactory for engineering purposes.