Impact of underfill filler particles on reliability of flip-chip interconnects

Parametric analytical studies are conducted to investigate whether the reliability of flip-chip solder interconnects are affected by inhomogeneities in the underfill, such as settling of the filler particles. The property gradation caused by filler settling is modeled with a micromechanics formulation. The predicted property gradients are then utilized in a finite element simulation of the flip-chip assembly, to assess the impact on solder interconnect reliability.