TY - GEN
T1 - Influence of Sb addition on microstructural evolution of Sn-Ag solder
AU - Lee, Hwa Teng
AU - Chen, Ming Hung
AU - Hu, Shuen Yuan
AU - Li, Cheng Shyan
N1 - Publisher Copyright:
© 2002 IEEE.
PY - 2002
Y1 - 2002
N2 - This paper investigates the influence of various levels of Sb addition on the microstructure of Sn-Ag hypoeutectic solder. To be precise, the microstructural evolution and the characteristics of Sn2.58Ag solder are studied for Sb additions of 1.75, 4.75 and 8.78wt%. The experimental results indicate that part of the Sb addition solutes into the β-Sn matrix, while the remainder reacts with the Ag and Sn atoms to form ϵ-Ag3(Sb,Sn) and SbSn compounds. It is noted that Ag3(Sb,Sn) is readily formed even when the level of Sb addition is low (1.75%). This suggests that the Sb atoms are quite active in substituting some of the Sn atoms in the Ag3Sn compound to form a nonstoichiometry compound, i.e. Ag3(Sb,Sn). In contrast, the SbSn phase is only identified when the Sb content exceeds 4.75%. After a process of deep etching, it is observed that the morphology of the Ag3(Sb,Sn) phase in the as-soldered condition possesses a long-strip-like appearance. However, it is shown that if the cooling rate is sufficiently slow, then the β-Sn matrix and the Ag3(Sb,Sn) compound tend to solidify simultaneously in the as-cast condition. A coarse laminated structure is observed and the Ag3(Sb,Sn) phase appears platelike. This results in a substantial reduction in the strength and ductility of the solder joint. Finally, it is shown that the size of the SbSn phase remains at a constant value of ca.30 μm for the two cooling rate conditions considered in the present investigation.
AB - This paper investigates the influence of various levels of Sb addition on the microstructure of Sn-Ag hypoeutectic solder. To be precise, the microstructural evolution and the characteristics of Sn2.58Ag solder are studied for Sb additions of 1.75, 4.75 and 8.78wt%. The experimental results indicate that part of the Sb addition solutes into the β-Sn matrix, while the remainder reacts with the Ag and Sn atoms to form ϵ-Ag3(Sb,Sn) and SbSn compounds. It is noted that Ag3(Sb,Sn) is readily formed even when the level of Sb addition is low (1.75%). This suggests that the Sb atoms are quite active in substituting some of the Sn atoms in the Ag3Sn compound to form a nonstoichiometry compound, i.e. Ag3(Sb,Sn). In contrast, the SbSn phase is only identified when the Sb content exceeds 4.75%. After a process of deep etching, it is observed that the morphology of the Ag3(Sb,Sn) phase in the as-soldered condition possesses a long-strip-like appearance. However, it is shown that if the cooling rate is sufficiently slow, then the β-Sn matrix and the Ag3(Sb,Sn) compound tend to solidify simultaneously in the as-cast condition. A coarse laminated structure is observed and the Ag3(Sb,Sn) phase appears platelike. This results in a substantial reduction in the strength and ductility of the solder joint. Finally, it is shown that the size of the SbSn phase remains at a constant value of ca.30 μm for the two cooling rate conditions considered in the present investigation.
UR - http://www.scopus.com/inward/record.url?scp=84966546576&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84966546576&partnerID=8YFLogxK
U2 - 10.1109/EMAP.2002.1188827
DO - 10.1109/EMAP.2002.1188827
M3 - Conference contribution
AN - SCOPUS:84966546576
T3 - Proceedings of the 4th International Symposium on Electronic Materials and Packaging, EMAP 2002
SP - 139
EP - 144
BT - Proceedings of the 4th International Symposium on Electronic Materials and Packaging, EMAP 2002
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 4th International Symposium on Electronic Materials and Packaging, EMAP 2002
Y2 - 4 December 2002 through 6 December 2002
ER -