Comparative Study of Interfacial Reactions of High-Sn Lead-free Solders on Single Crystal Cu and on Polycrystalline Cu
This work compared the interfacial reactions of single crystal Cu and polycrystalline Cu with the high-Sn solders. The morphology aspects of Cu6Sn5 intermetallic compound (IMC) grains formed between (001) single crystal Cu and high-Sn solder bath (pure Sn, Sn-0.7Cu, Sn-3Cu) at 250℃ and 300℃ for different durations ranging from 10 s to 10 min were investigated. The Cu6Sn5 grains formed in all solder baths at 250℃ displayed common scallop-type, while those formed in pure Sn and Sn-0.7Cu baths at 300℃ displayed rooftop-type in early stage of the interfacial reaction (less than 10 min). Both the top-view morphology and cross-section morphology of the interfacial Cu6Sn5 IMC formed on single crystal Cu at 300℃ are different from those formed on polycrystalline Cu. From the top-view, the rooftop-type Cu6Sn5 grains formed on (001) single crystal Cu are elongated along two perpendicular directions; from the cross-section view, the IMC layers present a relatively planar intermetallic structure. Furthermore, Cu6Sn5 grains formed between Sn-0.7Cu/(001)Cu partly changed from rooftop-type to scalloptype when the reaction time is up to 10 min; Cu6Sn5 grains formed between pure Sn/(001)Cu remained rooftop-type even after the reaction for up to 10 min. It is considered that reaction temperature and Cu concentration in the solder bath have an effect on the formation of rooftop-type Cu6Sn5 grains. The dissolution rate of single crystal Cu in the high-Sn solder is higher than polycrystalline Cu in solder bath at 300℃, which indicated that the morphology of Cu6Sn5 affects the dissolution of substrate Cu.
Yipeng Cui Mingliang Huang
Electronic Packaging Materials Laboratory, School of Materials Science & Engineering, Dalian Univers Electronic Packaging Materials Laboratory, School of Materials Science & Engineering, Dalian Univers
国际会议
北京
英文
593-596
2009-08-10（万方平台首次上网日期，不代表论文的发表时间）