Journal of Electronic Materials

, Volume 36, Issue 2, pp 168–172

Electromigration-Induced Bi Segregation in Eutectic SnBi Solder Joint

Regular Issue Paper

DOI: 10.1007/s11664-006-0025-0

Cite this article as:
Chen, CM., Chen, LT. & Lin, YS. Journal of Elec Materi (2007) 36: 168. doi:10.1007/s11664-006-0025-0

Effects of current stressing of 6.5 × 103 A/cm2 on the eutectic SnBi solder joint at 70°C were investigated. The Bi segregation at the anode side was found, and the Bi segregation layer grew with the increasing stressing time. The Bi segregation may result in the strength reduction and the more serious Joule heating due to the brittleness and the higher resistivity of Bi, respectively. Effects of the solder microstructure and the current density on the Bi segregation were also investigated. By preannealing the solder joint at 120°C for 192 h to 360 h before current stressing, the growth rate of the Bi segregation layer was significantly reduced due to the reduction of the density of the interphase boundary. The layer growth rate was also greatly reduced by reducing the current density from 6.5 × 103 A/cm2 to 5 × 103 A/cm2.

Keywords

Electromigration solder segregation 

Copyright information

© TMS 2007

Authors and Affiliations

  1. 1.Department of Chemical EngineeringNational Chung-Hsing UniversityTaichungTaiwan, Republic of China

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