Microstructure, chemistry and mechanical properties of the Ni/AgBiCuSn/Ni interconnections

摘要

The paper presents results of electron microscopy studies on the microstructure, chemical composition and mechanical properties of the Ni/AgBiCuSn/Ni interconnections obtained due to the conventional soldering. The scanning (SEM) and (TEM) transmission electron microscopy combined with an energy dispersive X-ray spectroscopy allowed to reveal the presence of two intermetallic phases (Ag_3Sn and Cu_6Sn_5) in the whole interconnection area for all the applied solders and soldering times. In the vicinity of Ni substrate both phases were modified with Ni (2-4.5 %at.). Some of Ag_3Sn precipitates took the elongated shape and they were located across whole interconnection width. The SEM examination after shear test showed that the joints ruptured in a ductile manner, as manifested by the dimples present on the fracture surfaces. The dimples prove also that the plastic deformation occurred along the loading direction.