Computational analyses on the effects of irregular conditions during accelerated thermal cycling tests on board level solder joint reliability

This study is intended to investigate the effects of irregular conditions on the board level solder joint reliability during accelerated thermal cycling tests. In a previous research, the thermal fatigue lives of PBGA solder joints have been estimated using a 2-dimensional finite element model. The computational results agreed very well with the experimental data. In the present study, with the previously developed finite element model, three cases of parametric studies are performed. In actual thermal cycling tests, it is usually quite difficult to achieve the ideal temperature profile in four linear segments as ramp-up, high temperature dwell, ramp-down, and low temperature dwell. The first case of the present study is to investigate the effect of imperfect temperature profile on the thermal fatigue life of PBGA solder joints. The second case under investigation is the effect of service interruption of the thermal cycling machine during the test. A certain time period of constant room temperature is inserted in the middle of the original temperature profile to simulate the breakdown of thermal cycling machine. In the third case, different starting temperatures are specified in order to simulate the effect of different stress free temperatures. The results of various computational analyses are compared and discussed in details