| Due to the environment and health problems causing by the use of lead, lead-freeelectronic packaging has come into the manufacturing for modern electronic products. Thekey problem of lead-free electronic packaging is the lead-free soldering process. And thelead-free solder materials play a crucial role in the lead-free soldering process. SAClead-free solder is recognized as the alternative to take place of the traditional tin-leadeutectic solder. And the SAC305solder is recommended as the best choice. But due to thehigh content of Ag, the cost increases nearly3times compared to tin-lead eutectic solder.To reduce the cost of solder, low-silver lead-free solder comes into people’s vision.SAC105is a kind of low-silver lead-free solder with a composition of98.5%Sn,1.0%Ag, and0.5%Cu. This paper focuses on the performance of SAC105solder throughthe designed experiments and tests.Studies have shown that: the microstructure and inter metallic compounds ofSAC105are similar to SAC305; the reduce of Ag content increases the solder’s meltingpoints, and the melting temperature range of SAC105is215-231°C nearly5°C higher thanSAC305; SAC105alloys possess lower tensile strength and higher elongation ratio thanSAC305, but in the solder joint shear strength tests, SAC105and SAC305show almostthe same shear strength; the wetting angle of SAC105/Cu is31°and is about to achievethe excellent evaluation of wetting criteria(below30°); in the high temperature storageexperiments, the SAC105/Cu IMC grows a little bit faster than SAC305and shows similarchanges in morphology to SAC305, after2000hours storage the SAC105joint shearstrength decreases about13%and is close to SAC305.As can be seen, the low-silver lead-free solder SAC105shows similar performance tothe recommended lead-free solder SAC305, while providing much lower cost. Proper useof low-silver lead-free solder can reduce the cost significantly. We do think that thelow-silver lead-free solder SAC105is very promising. |
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