Preferred orientation relationship between Cu6Sn5 scallop-type grains and Cu substrate in reactions between molten Sn-based solders and Cu

Abstract

A strong crystallographic orientation relationship between the Cu6Sn5 scallop-type grains and their Cu substrate has been found by synchrotron micro-x-ray diffraction study. Even though the crystal structures of Cu6Sn5 (monoclinic) and Cu (face-centered-cubic) are very different, angular distributions of crystallographic directions between Cu6Sn5 and Cu revealed a strong orientation relationship. Both SnPb solder and pure Sn showed the same result, indicating that this is general behavior between Sn-based solders and Cu. The strong orientation relation suggests that Cu6Sn5 forms prior to Cu3Sn in the wetting reactions. A total of six different orientation relationships were found. In all the cases, the [1¯01] direction of Cu6Sn5 preferred to be parallel to the [110] direction of Cu with a misfit of 0.24%. Due to pseudohexagonal structure of the Cu6Sn5, the six relationships can be categorized into two groups. From the orientation distribution, one group was found to be less rigid then the other group.

Growth mechanisms of Cu3Sn on polycrystalline and single crystalline Cu substrates

“…Therefore, the orientation relationship between the IMC and Cu can only be summarized as different groups. For example, according to synchrotron micro-X-ray diffraction there are six groups of orientation relationships between Cu 6 Sn 5 and Cu [20], while according to the electron backscattered diffraction method there are four groups of parallel planes and five groups of parallel directions between Cu 6 Sn 5 and Cu [12]. The orientation relationship between Cu 3 Sn and Cu has not been studied systematically before.…”

Anisotropic Crystal Plasticity Finite Element Modeling of the Effect of Crystal Orientation and Solder Joint Geometry on Deformation after Temperature Change

“…5 for all three tin crystal orientations used in this analysis, the internal energy is slightly lower for the model having isotropic properties, but this is insignificant compared with the effect of tin orientation. It is known that the copper texture affects the orientation and morphology of Cu 6 Sn 5 that forms in the interface, 67 but from this analysis it is clear that elastic anisotropy of the substrate is not likely to have a large influence on the deformation of tin. Figure 6 shows the von Mises stress distribution for the shear lap model and four different tin orientations.…”

TEM Observations of the Growth of Intermetallic Compounds at the SnBi/Cu Interface

“…2a), direct connection between Cu 6 Sn 5 and Cu could be found in some areas, where the orientation relationship can be determined. The growth relationship between Cu and Cu 6 Sn 5 has been studied by Suh et al 16 and Zou et al 10 by using synchrotron micro x-ray diffraction and electron backscatter diffraction (EBSD) methods, respectively. Here this is also verified by the corresponding selected-area electron diffraction (SAED) pattern of the Cu/Cu 6 Sn 5 interface in Fig.…”