Effect of electromigration induced joule heating and strain on microstructural recrystallization in eutectic SnPb flip chip solder joints

Fan Yi Ouyang*, King-Ning Tu, Yi Shao Lai

*Corresponding author for this work

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

A refinement of the lamellar microstructure was observed in eutectic SnPb solder joints in electromigration. Electromigration has both atomic flux and electron flow. The latter generated joule heating and the former caused strain. The formation of nanoscale lamellar microstructure spent a large amount of interfacial energy, and we proposed that the driving force comes from the strain induced by electromigration under a high current density. Kinetically, refinement of the lamellar microstructure required fast atomic diffusion at a high homologous temperature. The joule heating mainly from the on-chip Al interconnect lines tremendously increased the temperature of solder bumps and enabled fast atomic diffusion. The strain induced by electromigration, when combined with a high homologous temperature, could lead to recrystallization in the sample to form the nanoscale lamellae. Highlights: A refinement of the lamellar microstructure was observed after electromigration. The strain induced by electromigration under a high current density is estimated. A possible mechanism on the formation of nano-scale lamellae is proposed. Electromigration induced two extreme microstructure changes is compared.

Original languageEnglish
Pages (from-to)210-218
Number of pages9
JournalMaterials Chemistry and Physics
Volume136
Issue number1
DOIs
StatePublished - 14 Sep 2012

Keywords

  • Alloys
  • Electron microscopy
  • Microstructure
  • Recrystallization

Fingerprint Dive into the research topics of 'Effect of electromigration induced joule heating and strain on microstructural recrystallization in eutectic SnPb flip chip solder joints'. Together they form a unique fingerprint.

  • Cite this