Electromigration in the flip chip solder joint of Sn-8Zn-3Bi on copper pads

W. H. Lin, Albert T. Wu, S. Z. Lin, T. H. Chuang, K. N. Tu

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Electromigration in Sn-8Zn-3Bi flip chip solder bumps on Cu pads has been studied at 120°C with an average current density of 4 × 10 3 A/cm 2 and 4.5 × 10 4 A/cm 2. Due to the polarity effect, the thickness of the intermetallic compound Cu-Zn (γ-phase) formed at the anode is much greater than that at the cathode. The solder joint fails after 117 h of stressing at 4.5 × 10 4 A/cm 2, and void formation at the cathode can clearly be seen after polishing. However, it is the melting at the edge of the bump that causes the solder joint to fail. A simulation of the current density distribution indicates that the current density is not distributed uniformly, and current crowding occurs inside the bump. The results indicate that the increase of current density associated with Joule heating has affected melting and enhanced damage in the solder joint during electromigration.

Original languageEnglish
Pages (from-to)753-759
Number of pages7
JournalJournal of Electronic Materials
Issue number7
StatePublished - Jul 2007


  • Current crowding
  • Electromigration
  • Flip chip
  • Joule heating
  • Sn-8Zn-3Bi


Dive into the research topics of 'Electromigration in the flip chip solder joint of Sn-8Zn-3Bi on copper pads'. Together they form a unique fingerprint.

Cite this