Design, fabrication and comparison of lead-free/eutectic solder joint reliability of flip chip package

This investigation presents a detailed design procedure for a lead-free flip chip BGA package which includes solder bump profile prediction, FEM simulation, test vehicle design/fabrication and accelerated thermal cycle (ATC) testing to study the reliability issues of the flip chip packages. The solder joint reliability of a flip chip package depends on the solder materials and the solder geometry. Therefore, this study is divided into two main topics: one is the effect of solder joint material (eutectic 63Sn/37Pb solder and lead-free 96.5Sn/3.5Ag solder) on the solder joint reliability, and the other is the effect of the geometry on the Sn/Ag solder joint reliability. The trends of the ATC testing coincide with the FE analysis results, thus confirming that this analysis-fabrication procedure is feasible for the solder joint geometry and material design of a flip chip BGA package.