Optimal combination of soldering conditions of BGA for halogen-free and lead-free SMT-green processes

As from July 1, 2006, the European Union officially enforced prohibition of the use of six designated hazardous substances under the restriction of hazardous substances (RoHSs), including lead, cadmium and others. In addition, as from 2008, the requirements of green products had been made stricter by adding prevented use of halogen as the standard. When confronted with the two harsh lead-free and halogen-free conditions, the customary input settings of soldering manufacturing process by using surface mount technology (SMT) faces tremendously challenged. Therefore, to improve the reliability of electronic products in the entire lead-free and halogen-free SMT-green process, this study performs comprehensive experiments and employs analysis and improvement methods including the experimental design, analysis of variance, and statistical process control to determine the optimal combination of soldering conditions for the integrated-circuit solder ball of ball grid array (BGA). The results conclude aspects of the utilization method of solder paste, setting of parameters for solder printer, the temperature profile for the reflow oven, the proportion of pad to solder paste amount, and brand selection of the solder paste. Overall, the average soldering strength improves from 165.5 to 298.3gf, which is 80.24% increase. In general, this study allows electronic industry to consider environmental concerns along with the traditionally evaluated parameters of reliability and cost.