Electromigration induced growth behaviors of tin whisker on tin coating

In this paper, the effect of electromigration on growth behaviors of tin whisker on the tin coating with a thickness of 6.5 μm was investigated, the current density was 0.3×10⁴ A/cm², and electromigration loading time was 0 h, 48 h, 144 h and 240 h respectively. The results show that electromigration accelerate the tin whisker formation and growth on the electroplated tin coating, and the length of the tin whiskers increases with the increasing of electromigration time. In addition, voids occur firstly at the cathode after current loading. With longer loading time, voids are observed at both anode and cathode, and cracks are also found at the cathode. The length of tin whiskers increases with the increasing of current density. The average maximum crack width is close to 9.2 μm with the current density of 0.5×10⁴ A/cm².