Process and material effects on BGA board level solder joint reliability

This paper investigates the material, process and design influences on the reliability of BGA solder joints. The used methodology is a design of experiments. Factors are pad finish, type of solder paste, peak temperature, storage condition, the number of soldering cycles, the applied solder volume, and the land pad diameter. The reliability criterion is the number of failures after a thermo cycle test has been applied (5000TC). Failures have been detected using an electrical online measurements system. The effects on several process quality control variables and the target variable was evaluated. Results show that design parameters of the PCB affect the reliability significantly. Also material decisions have an impact on reliability. However, the assessed process variables do not show significant influences on reliability.