Electromigration-induced Kirkendall voids at the Cu/Cu3Sn interface in flip-chip Cu/Sn/Cu joints

C. Y. Liu, J. T. Chen, Y. C. Chuang, Lin Ke, S. J. Wang

Research output: Contribution to journalArticlepeer-review

67 Scopus citations


Polarity void formation has been observed at the Cu3 SnCu interfaces in current-stressed CuSnCu flip-chip joints. Electromigration voids were observed at the Cu3 SnCu anode interface, but no voids were found at the Cu3 SnCu cathode interface. The backstress in the anode's Cu trace line caused a vacancy backflow toward the Cu3 SnCu anode interface, which led to serious void formation. In the opposite Cu3 SnCu cathode interface, Cu atoms in the cathode's Cu trace line electromigrated toward the Cu3 SnCu cathode interface, which alleviated or healed possible Kirkendall void formation due to the normal annealing process.

Original languageEnglish
Article number112114
JournalApplied Physics Letters
Issue number11
StatePublished - 2007


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