Effect of Sn Grain Orientation on Electromigration Degradation Mechanism in High Sn-Based Pb-free Solders

Copyright © (2008) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics

Electromigration induced damage is strongly depend on Sn-grain orientation in Pb-free solders. Rapid depletion of intermetallic-compounds and Under-Bump-Metallurgy led to significant damages are caused by fast diffusion of Cu and Ni along the c-axis of Sn crystals. When c-axis of Sn-grain is not aligned with the current direction, electromigration damage is dominated by Sn self-diffusion, which takes longer to occur. This is a direct proof of the highly anisotropic diffusion behavior in Sn. Due to the presence of twin structures and stable Ag3Sn network, SnAg(Cu) solders are less susceptible to grain orientation effects and showed better electromigration performance than SnCu solders.

By: Minhua Lu; Da-Yuan Shih; Paul Lauro; Charles Goldsmith; Donald W. Henderson

Published in: Applied Physics Letters, volume 92, (no 21), pages Art. No. 211909 in 2008


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