Non-Destructive Orientation Mapping with X-ray Diffraction for Electronic Packaging Applications

The degradation of lead-free solder is caused by the multiplication of dislocations and the formation of subgrain boundaries. Although crystallographic orientation microscopy (OM) using electron backscatter diffraction (EBSD) is sensitive to dislocation density and subgrain boundaries, destructive EBSD-OM cannot allow us to track dislocation multiplication and subgrain-boundary formations in thermo-mechanical fatigue processes. In this study, we propose a non-destructive OM method using X-ray diffraction (XRD), which is based on a three-dimensional X-ray diffraction (3DXRD) technique. Difficulty in applying 3DXRD to plate-like specimens is solved by introducing the geometry of X-ray laminography to 3DXRD. We tested this laminographic 3DXRD for electronic packaging applications at SPring-8. We successfully demonstrated non-destructive orientation mapping for a solder ball and a plate-like specimen. The non-destructive XRD-OM method will facilitate the development of reliable electronic packaging by quantitatively evaluating the degradation of lead-free solder inside the packages.