Electromigration study on Cu-Sn interconnections

This research concerns the influence of electron current on the diffusion of Sn and Cu in simple Cu-Sn and Cu-Sn-Cu diffusion couples. The diffusion couples are designed to permit in situ studies of the progress of diffusion. Initial tests were done in 60/spl deg/C air with a current density of 1 /spl times/ 10/sup 4/A/cm/sup 2/. The results showed Cu movement into Sn in the direction of the electron current. With accompanying grain boundary sliding of the Sn grains. There is also evidence for Sn flow in the direction opposite the electron current.