A Time Frequency Domain Based Approach for Bga Solder Joint Fatigue Analysis Using Global Local Modeling Technique

The fatigue life prediction of the electronic packages under dynamic loading conditions is an increasingly important area of research, with direct application in packaging industries. Current life prediction methodologies are, in general, developed through a finite element (FE) model that is correlated using an experimental data measured through sweep sine testing. The frequency response curve (FRF) generated by using a sweep sine testing may suffer from leakage and windowing of the signal may not work correctly, which results in the shift in the amplitude and the resonance frequencies of the package. In consequence, there will be a significant deviation between the actual and the predicted natural frequencies and the amplitude of vibration response in the given excitation range, resulting in the longer time to fail the package during the laboratory based /virtual durability testing. Thus, it is necessary to develop a suitable validation technique in time/frequency domain to address this issue. In this paper, the step sine testing procedure is utilized to validate the FE model of a test vehicle consisting of a board level BGA chip package and the resonance based fatigue testing is performed in the FE based simulation. The global-local modeling approach is utilized to model the test vehicle and the volume average von Mises stress is used to predict the life of the solder joint. Following the numerical simulations, fatigue test is carried out in the test vehicle at the first resonance frequency obtained from the step sine test. Experimental results show that there are full openings of the corner balls in a very short interval of time. The results of the life prediction from the FE model and from experiments are comparable to each other thus validating the proposed methodology.