Lead-free 96.5Sn-3.5Ag flip chip solder joint reliability analysis

Lead-free 96.5Sn/3.5Ag flip chip solder joints were subjected to both thermal shock (-55/spl deg/C to 125/spl deg/C) and thermal cycling (-40/spl deg/C to 125/spl deg/C) reliability tests respectively. Two-parameter Weibull distribution plots, the Mean Time to Failure (MTTF) life are compared. Scanning electron microscopy (SEM) examination was performed on the cross-section surface of failed samples to observe the failure sites and modes. Finite element modeling and simulation of the thermal cycling and thermal shock tests were simulated. An elastic-plastic-creep analysis model was implemented to simulate time independent plasticity and time dependent creep deformations in the solder joints. Solder joint fatigue models were used for life prediction analysis employing the inelastic strain parameters derived from the finite element results.