Sensitivity analysis of technological fabrication tolerances on the lifetime of flip-chip solder joints

In this paper we discuss the influence of solder joint geometry on the lifetime of a flip chip assembly. Geometry variations caused by variations of solder volume, pad configuration, and pad size on the printed circuit board (PCB) were taken into account. Typically these parameters vary due to technological fabrication tolerances. Consequently, the influence of such design aspects on system reliability was studied in detail by using finite element analysis (FEA) models. Selected solder joint geometry variations were assembled and tested in a thermal cycling chamber. Simulation and experimental results were compared and some advice is given regarding their evaluation.