Joule heating enhanced phase coarsening in Sn37Pb and Sn3.5Ag0.5Cu solder joints during current stressing

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Detail(s)

Original languageEnglish
Pages (from-to)469-476
Journal / PublicationJournal of Electronic Materials
Volume37
Issue number4
Publication statusPublished - Apr 2008

Abstract

This paper investigated the effect of Joule heating on the phase coarsening in Sn37Pb and Sn3.5Ag0.5Cu ball grid array (BGA) solder joints stressed at -5°C and 125°C with a 6.0 × 10 2A/cm 2 electric current. The phase growth under current stressing was also compared with those under aging at 125°C. It was found that the current stressing produced a substantial Joule heating in the solder joints and conductive traces. Hence, the solder joints underwent a considerable temperature rise by 30-35°C when stressed at -5°C and 125°C in this study. Coarsening of Pb-rich and Ag-rich phases was confirmed to be accelerated by the current stressing as a result of enhanced diffusion at elevated temperature and atomic stimulation due to numerous collisions between electrons and atoms. Different controlling kinetics were suggested for the cases stressed or aged at different temperatures. © 2008 TMS.

Research Area(s)

  • Ball grid array (BGA) solder joints, Current stressing, Diffusion, Joule heating, Phase coarsening