TEM investigation of interfacial microstructure and fracture mode of the Sn-Ag-Cu/Ni joint system

Autor: P.T. Lee, M.K. Lu, Cheng-En Ho, Y.H. Huang, W.L. Chou
Rok vydání: 2017
Předmět:
Zdroj: Materials Science and Engineering: A. 706:269-278
ISSN: 0921-5093
DOI: 10.1016/j.msea.2017.08.116
Popis: The effects of Cu concentration ( x ) on the interfacial microstructure between a molten Sn-3Ag- x Cu alloy and an electrolytic Au/Ni/Cu multilayer and its mechanical reliability were investigated via transmission electron microscopy (TEM) and high-speed ball shear (HSBS) testing. The x values were 0, 0.3, 0.4, 0.5, 0.7, and 1.0 (wt%). An increase in x caused an interfacial intermetallic compound (IMC) transition from a dense (Ni,Cu) 3 Sn 4 layer ( x = 0 and 0.3) to the coexistence of (Ni,Cu) 3 Sn 4 and (Cu,Ni) 6 Sn 5 ( x = 0.4 and 0.5), and to a dense (Cu,Ni) 6 Sn 5 layer ( x = 0.7 and 1.0) after soldering reaction at 250 °C for 2 min. An increase in the reaction time enhanced the IMC growth and induced the nucleation of a (Ni,Cu) 3 Sn 4 nanolayer beneath (Cu,Ni) 6 Sn 5 in the high x case. The TEM and HSBS characterizations showed that a single, thin (Ni,Cu) 3 Sn 4 layer grown at the interface possessed better shear resistance than a single (Cu,Ni) 6 Sn 5 layer, and the presence of a dual layer structure of (Cu,Ni) 6 Sn 5 /(Ni,Cu) 3 Sn 4 substantially degraded the mechanical properties of the joint interface. These observations indicated that the Cu concentration in Sn-3Ag- x Cu alloy plays a crucial role in the interfacial reaction, which, in turn, dominates the mechanical reliability of microelectronic joints.
Databáze: OpenAIRE
Externí odkaz: