Effects of Ag addition and Ag3Sn formation on the mechanical reliability of Ni/Sn solder joints

초록

Formation of intermetallic compounds (IMCs) in solder joints is closely associated with the mechanical reliability of the system. Though internal voids formed in Ni/Sn solder joints are known to be related to the formation of Ni3Sn4IMC, a detailed study on the mechanical reliability has not yet been reported. In this study, the mechanical reliability of Ni/Sn joints was investigated using two different soldering systems: Ni/Ag-Ag/Sn/Ni bilayers and Ni/Sn/Ag-Ag/Sn/Ni sandwich structures. The failure mode was found to be closely related to the formation and growth of an Ag3Sn phase. Filling of the voids with Ag3Sn IMC resulted in maximum shear strength, with a failure locus through Ni3Sn4 and Ag3Sn. However, formation of a large amount of Ag3Sn decreased the shear strength once again. (C) 2017 Elsevier Ltd. All rights reserved.

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