Interfacial Segregation of Bi during Current Stressing of Sn-Bi/Cu Solder Interconnect

Authors: Yang, Q.L.; Shang, J.K.

Source: Journal of Electronic Materials, Volume 34, Number 11, November 2005 , pp. 1363-1367(5)

Publisher: Springer

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Abstract:

Effect of electromigration on the interfacial structure of solder interconnects was examined in a Sn-Bi/Cu interconnect system. At current densities above 10⁴ A/cm², Bi migrated along the direction of the electron flow in the solder alloy. A continuous Bi layer was found at the solder interface on the anode side, while a Sn-rich region formed at the cathode side of the electrical connection. The presence of the Bi layer inhibited further growth of Cu-Sn intermetallic phase at the interface by acting as a diffusion barrier to the reacting species.

Keywords: ELECTROMIGRATION; SOLDER; INTERCONNECT; INTERFACE

Document Type: Regular paper

Publication date: 2005-11-01