Effects of different temperature profile on solder joints in PBGA packages

With the current trend of cheaper, faster, and better electronic equipment, it has become increasingly important to evaluate the package and system performance very early in the design cycle using simulation tools [1]. Many studies have shown that the profile of temperature has a great impact on solder joint reliability. Undergoing the different temperature profile will get a different solder joint fatigue life. There is an acceleration model which consists of three variables: the maxtemperature, frequency and arrange of temperature, for lead free (SAC) solder joint reliability under thermal cycling. However, there is a different fatigue life undergoing the temperature profile with the same max-temperature, frequency and arrange of temperature, the ratio of dwelling time/ramp time has a great influence on the fatigue life of lead free solder. In this paper, a parameterized finite element model is presented and used to analyze the change in accumulated inelastic energy density in the solder joint with different ratio of dwelling time/ramp time. By compared the results of each case, it will be shown that the ratio of dwelling time/ramp time has a significant influence on the reliability of solder joints.