Ni Interdiffusion Coefficient and Activation Energy in Cu6Sn5

作者:Huang Kuan Chih*; Shieu Fuh Sheng; Hsiao Y H; Liu C Y
来源:Journal of Electronic Materials, 2012, 41(1): 172-175.
DOI:10.1007/s11664-011-1821-8

摘要

Ni diffusion in Cu6Sn5 intermetallic compound was investigated. First, we successfully fabricated preferred-orientation Cu6Sn5 crystal by liquid-phase electroepitaxy (LPEE). Then, Ni/Cu6Sn5 diffusion couples were produced by sputtering from a Ni thin film onto the Cu6Sn5 crystal. Ni/Cu6Sn5 diffusion couples were annealed at different temperatures of 120A degrees C, 160A degrees C, 200A degrees C, 255A degrees C, 290A degrees C, and 320A degrees C for 2 h in a vacuum. The Ni atomic profile across the Ni/Cu6Sn5 interface was obtained by electron spectroscopy for chemical analysis (ESCA). From the Ni atomic profiles, the Matano method was used to evaluate the Ni interdiffusion coefficients ((D) over tilde (Ni)) in the Cu6Sn5 crystal obtained with different annealing temperatures, which then yields the activation energy for Ni diffusion in the Cu6Sn5 crystal at a particular Ni content. We found that, as Ni diffuses in the ternary Cu6-x Ni (x) Sn-5 compound phase, the activation energy of Ni interdiffusion decreases with the Ni content.