A predictive methodology for BGA solder joint formation and assembly defects

The successful formation of defect-free solder joints (SJs) during the BGA package surface-mount process is increasingly difficult to guarantee with increasing package body sizes and complex packaging architectures. Commonly used industry standards for surface-mount (SMT) requirements do not guarantee reliable SMT yield. This is because standards capture only a subset of parameters that influence SJ formation, rather than the full range of complex interactions between package/PCB design and SMT process parameters. In this work, a computational methodology has been developed to predict SJ defect formation risk for surface-mounted BGA package assemblies. Design-specific warpage limits that account for the interactions between package/PCB design, warpage, externally applied forces, and SMT process parameters are demonstrated. This methodology enables optimization of designs spanning the package, PCBA, and SMT process to predict and mitigate the risk of SJ defects during the assembly process.