Effect of mild aging on package drop performance for lead free solders

There have been tremendous demands on portable electronic devices since last decade and board level drop performance has become one of the major concerns in microelectronic ball grid array (BGA) package. Most studies focused on material selection of solder joints to improve drop performance. However, the risk for early failure in drop impact reliability still exists because it is sensitive to several factors such as substrate supplier, reflow conditions, loading condition and aging. In this paper, mild aging effect on drop performance was investigated to reduce early failure risk for lead free solder joints. From this study, for the case of relatively poor performance and interface dominant failure mode, mild aging could improve initial drop life with brittle-to-ductile transition.