Atomistic Simulation of Stress-Induced Grain Boundary Diffusion: For Tin-Whisker Problem

Abstract:

The problem of whisker formation in tin (Sn) wiring in small electronic devices has become an important issue with the requirement of lead-free wiring, because doping of Pb to reduce whisker formation cannot be applied. It is therefore urged to better understand stress migration in tin, which is suspected to play a key role in whisker growth. We aim to study grain boundary diffusion in tin by atomistic simulation. After constructing an efficient interatomic potential suitable for diffusion of atoms using the genetic algorithm (GA), we perform molecular dynamics (MD) simulation of grain boundary diffusion in Sn under stress. We find that the magnitude of stress effect on diffusion depends on the boundary structure. Moreover, we examine the effect of impurities on vacancy migration by ab initio calculation to find atom doping that has potential to suppress diffusion.

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 1545-1549
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.1545
• Online since: January 2012
• Authors: Yoshitaka Umeno, Jun Negami
• Keywords: Grain Boundary Diffusion, Molecular Dynamic (MD), Stress Migration, TiN Whisker

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