Electromigration-Induced Surface Drift and Slit Propagation in Polycrystalline Interconnects: Insights from Phase-Field Simulations

Arnab Mukherjee, Kumar Ankit, Michael Selzer, Britta Nestler

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

We employ the phase-field method to assess electromigration (EM) damage in wide polycrystalline interconnects due to grain-boundary grooving. An interplay of surface and grain-boundary diffusion is shown to drastically influence the mode of progressive EM damage. Rapid atomic transport along the surface leads to shape-preserving surface drift reminiscent of Blech drift-velocity experiments. On the other hand, a comparatively faster grain-boundary transport localizes the damage, resulting in the proliferation of intergranular slits with a shape-preserving tip. At steady state, the two regimes exhibit exponents of 1 and 3/2, respectively, in Black's law. While surface drift obeys an inverse scaling with grain size, slits exhibit a direct relationship at small sizes, with the dependence becoming weaker at larger ones. Furthermore, we explain the influence of curvature- or EM-mediated healing fluxes running along the surface on groove replenishment. Insights derived from phase-field simulations of EM in bicrystals are extended to investigate the multiphysics of mixed-mode damage of a polycrystalline interconnect line that is characterized by a drift of small grain surfaces, slit propagation, and coarsening. The triple and quadruple junctions are identified as prominent sites of failure.

Original languageEnglish (US)
Article number044004
JournalPhysical Review Applied
Volume9
Issue number4
DOIs
StatePublished - Apr 4 2018

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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