Field condition reliability assessment for SnPb and SnAgCu solder joints in power cycling including mini cycles

Actual field conditions that computer components such as microprocessors experience are different from the accelerated thermal cycling tests typically used to perform reliability assessment. Field conditions can include longer dwell times, different temperature ramp rates driven by power ON/OFF events, and temperature fluctuations during the power ON state due to workload patterns. Series of numerical simulations have been performed to study the effect of the field conditions on the solder joint fatigue life of electronic packaging. The simulation results show that SnPb and SnAgCu solders respond differently with respect to dwell time and mini cycles. Without considering the effect of mini-cycles, it is possible that SnAgCu may fail earlier than SnPb with very long dwell time. However, it is important to note if mini-cycles contribute to damage as seen in this analysis, the SnPb solder will probably still fail before SnAgCu solder.