Quantitative X-ray microtomography study of 3-D void growth induced by electromigration in eutectic SnPb flip-chip solder joints

Vacancy flux in eutectic flip-chip SnPb solder joints driven by electromigration was studied using synchrotron radiation X-ray microtomography technique. The change in void volume and shape in three-dimensional images was measured quantitatively and the product of diffusivity and effective charge number of electromigration in eutectic SnPb alloy was calculated to be 3.3 × 10−9 and 9.5 × 10−9 cm2 s−1 at 100 and 120 °C, respectively. The activation energy of the effective self-diffusivity in SnPb alloy was measured to be 0.66 eV.