Influence of solder volume and interfacial reaction on the undercooling and solidification microstructure of BGA structure Cu/Sn-3.0Ag-0.5Cu/Cu joints
The solder joints volume and interfacial reaction during the soldering significantly affect its solidification behavior and microstructure feature; further,the microstructure of the solder matrix and the intermetallic compounds(IMC)have a direct impact on the performance and reliability of the solder joint.In this study,the effects of the solder volume and interfacial reaction on the undercooling behavior and solidification microstructure of ball grid array(BGA)structure Sn-3.0Ag-0.5Cu/Cu(SAC/Cu)single-sided and Cu/Sn-3.0Ag-0.5Cu/Cu(Cu/SAC/Cu)double-sided joints with different solder diameters(0.76,0.50 and 0.30 mm)were investigated by reflow soldering process using a differential scanning calorimeter(DSC).DSC reflow results show that the undercooling of both SAC/Cu single-sided and Cu/SAC/Cu double-sided joints decreases with the increase of solder ball diameter.However,there is no big difference in undercooling value between SAC/Cu and Cu/SAC/Cu joints with the same joint size(or solder ball size).Microstructural analysis shows that the primary solidification phase of 0.30-mm-diameter double-sided solder joints is Ag3Sn,instead of Cu6Sn5 in the solder joints with diameter of 0.50 and 0.76 mm,which leads to decrease of the undercooling of 0.30 mm solder joints to a value only a little higher than the undercooling of 0.50 mm solder joints.The undercooling of solder joints is influenced by several factors,mainly including the type of substrate material(UBM),solder dimension and primary solidification phase.
Lead-free solder Size effect Interfacial reaction Undercooling Microstructure
Lang Zhang Min-Bo Zhou Xin-Ping Zhang
Lab of Smart Materials and Electronic Packaging(SMEP)School of Materials Science and Engineering,South China University of Technology Guangzhou 510640,China
国际会议
The 15th International Conference on Electronic Packaging Technology (ICEPT 2014) ) (第十五届电子封装技术国际会议)
成都
英文
251-255
2014-08-12（万方平台首次上网日期，不代表论文的发表时间）