Three-dimensional placement rules of Cu6Sn5 textures formed on the (111)Cu and (001)Cu surfaces using electron backscattered diffraction. (15th March 2016) - Zhang, Zhihao
Abstract: In this work, the grain orientations and surface characteristics of Cu6Sn5 textures formed at the liquid-Sn0.7Cu |(111)Cu and liquid-Sn0.7Cu |(001)Cu joint interfaces were systematically investigated using the electron backscattered diffraction technique. The results showed that there were two dominant reasons for formation of the strong Cu6Sn5 textures on the (111)Cu and (001)Cu surfaces: (1) the low but not minimum lattice matches of Cu atoms between Cu6Sn5 and Cu phases in the in-plane orthogonal directions and (2) the axial growth behaviour of Cu6Sn5 phase. Based on these reasons, we proposed and verified two types of the three-dimensional placement rules of Cu6Sn5 textures to reveal the nucleation behaviour of Cu6Sn5 on Cu surfaces. In addition, the macroscopic shear strengths of Cu6Sn5 textures on the actual joint interfaces were also tested. Our study may help clarify the epitaxial growth mechanism of Cu6Sn5 phase on the (111)Cu and (001)Cu surfaces and provide a strong scientific basis of Cu6Sn5 orientation design for three-dimensional integrated circuit interconnect applications. Graphical abstract: Highlights: Regular arrays of Cu6 Sn5 textures on the (111)Cu and (001)Cu surfaces are studied by electron backscattered diffraction. 3D placement rules are proposed to explain the formation reason of Cu6 Sn5 textures on the (111)Cu and (001)Cu surfaces. Cu6 Sn5 textures on (111)Cu surfaces are more suitable for use as interfacial layers to resist shear failures in 3D-ICs.