Laser and hot air reflow soldering of PBGA solder ball was investigated. Experimental results showed that surface quality and shear strength of solder bump reflowed by laser was superior than the solder bump by hot ai...Laser and hot air reflow soldering of PBGA solder ball was investigated. Experimental results showed that surface quality and shear strength of solder bump reflowed by laser was superior than the solder bump by hot air, and the microstructure within the solder bump reflowed by laser was much finer. Analysis on interfacial reaction showed that eutectic solder reacted with Au/Ni/Cu pad shortly after the solder was melted. Interface of solder bump reflowed by laser consists of a continuous AuSn 4 layer and remnant Au element. Needle like AuSn 4 grew sidewise from interface, and then spread out to the entire interface region. A thin layer of Ni 3Sn 4 intermetallic compound was found at the interface of solder bump reflowed by hot air, and AuSn 4 particles distributed within the whole solder bump randomly. The combination effect of the continuous AuSn 4 layer and finer eutectic microstructure contributes to the higher shear strength of solder bump reflowed by laser.展开更多
Nanoindentation test is performed on study the plastic and creep properties of the Sn-Ag-Cu （SAC） lead-free ball grid array （ BGA ） solder joints. The dynamic hardness of two kinds of solder joints decreases with ...Nanoindentation test is performed on study the plastic and creep properties of the Sn-Ag-Cu （SAC） lead-free ball grid array （ BGA ） solder joints. The dynamic hardness of two kinds of solder joints decreases with indentation depth increase. SACO705 BiNi/ Cu exhibits a higher ultimate dynamic hardness and a smaller indentation depth than SAC305/ Cu. Then the strain hardening phenomenon of SAC305/ Cu is more obvious compared to that of SACO705 BiNi/ Cu. The indentation creep of SACO705BiNi/ Cu solder joint is lower than that of SAC305/ Cu solder joint before and after thermal shock. The creep rate sensitive index of SACBiNi/Cu solder joint is lower than that of solder joint. SACO705BiNi/Cu solder joint is superior to SAC305/Cu solder joint in the anti-creep property. The plasticity of SACOTOSBiNi/Cu and SAC305/Cu solder joints are similar. Compared with SAC305 solder, the SACO705 BiNi solder pe^forms higher hardness and solder creep resistance and still maintains a good plasticity.展开更多
文摘Laser and hot air reflow soldering of PBGA solder ball was investigated. Experimental results showed that surface quality and shear strength of solder bump reflowed by laser was superior than the solder bump by hot air, and the microstructure within the solder bump reflowed by laser was much finer. Analysis on interfacial reaction showed that eutectic solder reacted with Au/Ni/Cu pad shortly after the solder was melted. Interface of solder bump reflowed by laser consists of a continuous AuSn 4 layer and remnant Au element. Needle like AuSn 4 grew sidewise from interface, and then spread out to the entire interface region. A thin layer of Ni 3Sn 4 intermetallic compound was found at the interface of solder bump reflowed by hot air, and AuSn 4 particles distributed within the whole solder bump randomly. The combination effect of the continuous AuSn 4 layer and finer eutectic microstructure contributes to the higher shear strength of solder bump reflowed by laser.
基金This work was supported by National Natural Science Foundation of China （ Grant No. 51174069 and 51075107） and Research Special Funds for Technology Creative Talents of Harbin （Grant No. 2013RFQXJ166）.
文摘Nanoindentation test is performed on study the plastic and creep properties of the Sn-Ag-Cu （SAC） lead-free ball grid array （ BGA ） solder joints. The dynamic hardness of two kinds of solder joints decreases with indentation depth increase. SACO705 BiNi/ Cu exhibits a higher ultimate dynamic hardness and a smaller indentation depth than SAC305/ Cu. Then the strain hardening phenomenon of SAC305/ Cu is more obvious compared to that of SACO705 BiNi/ Cu. The indentation creep of SACO705BiNi/ Cu solder joint is lower than that of SAC305/ Cu solder joint before and after thermal shock. The creep rate sensitive index of SACBiNi/Cu solder joint is lower than that of solder joint. SACO705BiNi/Cu solder joint is superior to SAC305/Cu solder joint in the anti-creep property. The plasticity of SACOTOSBiNi/Cu and SAC305/Cu solder joints are similar. Compared with SAC305 solder, the SACO705 BiNi solder pe^forms higher hardness and solder creep resistance and still maintains a good plasticity.
