TY - GEN
T1 - Influence of lanthanum addition on microstructure and Properties of Sn-3.5Ag solder system
AU - Lee, Hwa Teng
AU - Chen, Yin Fa
AU - Hong, Ting Fu
AU - Huang, Yu Jing
PY - 2008
Y1 - 2008
N2 - The goal of this research is to evaluate the effects of La addition on the microstructure and microhardness of Sn-Ag based solders. Sn3.5Ag-xLa ternary alloy solder were prepared by adding 0-1.0wt% La into a Sn-3.5Ag alloy. Copper substrates were then dipped into these solders and aged at 150°C for up to 625 hours. The microstructure and microhardness of the as solidified solder and the aged solder/copper couples were investigated. Experimental results show that Sn-3.5Ag-xLa solders are composed of -Sn, Ag3Sn and LaSn3 phases, and their microstructure is refined with La addition. After isothermal aging, Ag3Sn and IMC layer can be effectively depressed by adding a small amount of La element, and the size and amount of LaSn3 compounds did not change perceptibly with storage time. The addition of La increased the microhardness of the Sn-Ag solder due to the refining effect of Ag3Sn particles in eutectic and increased formation of LaSn3 compound. After isothermal storage, the microhardness of solders was decreased with the increasing coarsening of Ag3Sn compounds as aging time was increased. However, coarsening of Ag3Sn compounds was retarded by La addition as revealed in this study. Therefore, La addition helped to improve the microhardness and thermal resistance ofthe solder joints.
AB - The goal of this research is to evaluate the effects of La addition on the microstructure and microhardness of Sn-Ag based solders. Sn3.5Ag-xLa ternary alloy solder were prepared by adding 0-1.0wt% La into a Sn-3.5Ag alloy. Copper substrates were then dipped into these solders and aged at 150°C for up to 625 hours. The microstructure and microhardness of the as solidified solder and the aged solder/copper couples were investigated. Experimental results show that Sn-3.5Ag-xLa solders are composed of -Sn, Ag3Sn and LaSn3 phases, and their microstructure is refined with La addition. After isothermal aging, Ag3Sn and IMC layer can be effectively depressed by adding a small amount of La element, and the size and amount of LaSn3 compounds did not change perceptibly with storage time. The addition of La increased the microhardness of the Sn-Ag solder due to the refining effect of Ag3Sn particles in eutectic and increased formation of LaSn3 compound. After isothermal storage, the microhardness of solders was decreased with the increasing coarsening of Ag3Sn compounds as aging time was increased. However, coarsening of Ag3Sn compounds was retarded by La addition as revealed in this study. Therefore, La addition helped to improve the microhardness and thermal resistance ofthe solder joints.
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U2 - 10.1109/EMAP.2008.4784259
DO - 10.1109/EMAP.2008.4784259
M3 - Conference contribution
AN - SCOPUS:64049105541
SN - 9781424436217
T3 - 2008 10th International Conference on Electronic Materials and Packaging, EMAP 2008
SP - 183
EP - 186
BT - 2008 10th International Conference on Electronic Materials and Packaging, EMAP 2008
T2 - 2008 10th International Conference on Electronic Materials and Packaging, EMAP 2008
Y2 - 22 October 2008 through 24 October 2008
ER -