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The phenomenon of electromigration in Pb-free Sn-Ag-Cu solder joint specimen subject to high current density was characterized. Electromigration measurements in the direction of the electron flux, via Cu metal lines, ENIG metallization, and Sn-Ag-Cu solder joint is documented. The consequence of this migration phenomenon causes void formation and the significant accumulation of voiding is a serious reliability concern. Digital image speckle analysis (DISA) was used to measure the in-situ micro-deformation of a cross sectioned solder joints, which is subject to electromigration with a current density of 5*103A/cm2 under a constant temperature of 150°C. The deformation and strain field of the solder joint were analyzed by a digital image correlation software. After 120hrs thermal-current test, higher strain near large voids was detected. The IMC growth behavior with/without current are compared. It was noted that IMC layer growth on anode interface is faster than cathode interface, and both are faster than isothermal aging.