Ag Electromigration Against Electron Flow in Sn5Ag/Cu Solder Bump

作者:Tseng H W*; Yeh Y T; Lin K Y; Liu C Y
来源:Electrochemical and Solid-State Letters, 2009, 12(12): H445-H448.
DOI:10.1149/1.3236787

摘要

A phenomenon that can result in electromigration suppression in solder bumps on Cu pads is reported. Under certain current stressing conditions, Ag migrates against the electron flow and forms a Ag(3)Sn compound layer at the cathode Sn5Ag/Cu interface. This phenomenon implies that it is the electrostatic force rather than the typical wind force that is the dominant electromigration force acting on the Ag solute atoms in the Sn matrix. The Ag(3)Sn compound layer formed at the Sn5Ag/Cu joint interface could effectively retard electromigration-induced consumption on the Cu bump pad.