Measurement of acceleration factor for lead-free solder (SnAg3.8Cu0.7) in thermal cycling test of BGA components and calibration of lead-free solder joint model for life prediction by finite element analyses

Lead-free solder is taken into use in the electronics industry and there is a lack of data which shows how much thermal cycling tests accelerate the failure mechanisms compared to the real use conditions for the lead-free alloy. In this paper, a methodology on how to estimate the acceleration factor (AF) is described. The AF-experiments give an indication that the AF between the tests carried out at -40 - +125 °C and 30 - 80 °C is approximately 10 to 13. The test results have also been used to create a solder joint fatigue model for lead-free soldered BGA components. The model can be used to predict solder joint life by using finite element analyses in other environments.