Nonuniform and negative marker displacements induced by current crowding during electromigration in flip-chip Sn-0.7Cu solder joints

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • S. W. Liang
  • Hsiang-Yao Hsiao
  • Chih Chen
  • Luhua Xu
  • Yi-Shao Lai

Detail(s)

Original languageEnglish
Pages (from-to)2443-2448
Journal / PublicationJournal of Electronic Materials
Volume38
Issue number12
Publication statusPublished - Dec 2009
Externally publishedYes

Abstract

A quantitative analysis of the nonuniform distribution of current density and nonuniform rate of electromigration has been carried out by measuring the movement of an array of diffusion markers. Tiny marker arrays were fabricated by focused ion beam on the polished surface of flip-chip solder joints near the anode to measure the electromigration rate. The marker velocity at the current-crowding region was found to be at least five times larger than at locations far from the region. Some of the markers in the low-current-density region possess negative velocities, indicating that backflow occurs during the electromigration. The backflow, in which the atomic flow is against the electron flow, is explained by a constant-volume model as well as the back-stress induced by electromigration. © 2009 TMS.

Research Area(s)

  • Electromigration, Pb-free solder

Bibliographic Note

Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to lbscholars@cityu.edu.hk.

Citation Format(s)

Nonuniform and negative marker displacements induced by current crowding during electromigration in flip-chip Sn-0.7Cu solder joints. / Liang, S. W.; Hsiao, Hsiang-Yao; Chen, Chih et al.
In: Journal of Electronic Materials, Vol. 38, No. 12, 12.2009, p. 2443-2448.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review