Models correlation and comparison for solder joint reliability

In this paper, the solder joint life prediction under thermal cycling with different material constitutive relation is examined. A three-dimensional nonlinear finite element model is introduced by using the ANSYS APDL technique to be connected with the FORTRAN user defined subroutines of nonlinear material constitutive models. In addition, several other modeling related issues are explored with respect to the crack growth correlations. To better evaluate the solder joint structure integrity, a new constitutive model of the solder joint material is discussed by integrating a power law and Darveaux's constitutive model, then the correlating material model parameters are calculated through the combination of MATLAB tool with the routines of genetic algorithms. Impact of different meshes to the solder joint reliability is also discussed. Finally, an example of solder joint failure analysis under thermal loading conditions for CSP type BGA is investigated; its fatigue life is predicted using the new material model as well as power law and Darveaux's model. The simulation results exhibit a good correlation among different material models and test results.