Yield Study of Inline Package on Package (PoP) Assembly

This study is focused on the correlation between warpage of ball grid array (BGA) components and the yield of package-on-package (PoP) assembly on printed circuit board (PCB). Gap analysis and modeling have been employed to address the solder joint "open" defects. Warpage measurements for BGAs were performed under simulated reflow conditions. A yield prediction model is proposed based on modeling of the gap using Monte Carlo simulation. The root causes for yield loss have been identified from this study and recommendations are made to enhance the inline assembly yield for PoP.