Electromigration in Bi-crystal pure Sn solder joints: Elucidating the role of grain orientation

Marion Branch Kelly, Sridhar Niverty, Nikhilesh Chawla

Research output: Contribution to journalArticle

Abstract

Intermetallic compound (IMC) and void growth are electromigration (EM) damage mechanisms that are controlled by the anisotropic diffusion of Cu in β-tetragonal Sn solder joints. Single crystal fast diffusion, slow diffusion, and bicrystal solder joints were fabricated and tested under thermal aging and EM conditions to investigate the effect of grain orientation on microstructure evolution including IMC growth, void growth and grain structure. Sample and testing geometry ensured there were no effects from current crowding or joule heating so that crystallographic effects could be isolated. Microstructure characterization by scanning electron microscope (SEM), electron backscatter diffraction (EBSD) and X-ray microtomography revealed interface-nucleated and bulk-nucleated IMC growth, particle stimulated nucleation (PSN) of recrystallized grains, and two unique voiding behaviors, void faceting and void burrowing. The relationship between these features and β-Sn grain orientation and implications for EM damage mitigation are discussed.

Original languageEnglish (US)
Article number152918
JournalJournal of Alloys and Compounds
DOIs
StateAccepted/In press - Jan 1 2019
Externally publishedYes

Keywords

  • Anisotropy
  • Crystal structure
  • Diffusion
  • Intermetallics
  • Semiconductors

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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