| dc.description.abstract | To study the kinetics of Cu dissolution induced by electromigration,we produce a flip chip structure by connecting two Cu foil with a solder
bump. Three different Sn-Cu solders are studied which are Sn, Sn0.7Cu,and Sn3.0Cu. The solder bumps are stressed by current density of
104(amp/cm2) at three elevated temperatures, which are 155 ºC, 180 ºC,and 200ºC.
The result shows that electromigration will cause the consumption in the cathode Cu pad. It is because that once Cu atoms dissolve into Sn,
they are transported to the anode interface quickly. Hence, the solubility of Cu in Sn near the interface between IMC and Sn at the cathode side is always maintain unsaturated. We conclude that the dissolution process of Cu into Sn controls the Cu foil consumption.
The activation energy of EM-induced Cu consumption of three
solders, Sn, Sn0.7Cu, Sn3.0Cu, is about 0.68eV, 0.72eV,and 0.73eV
respectively. Adding Cu into Sn solder can reduce electromigration
effect.
By the way, a critical temperature that can distinguish two type
electromigration failure modes is about 55.3oC. At higher the critical
temperature, Cu dissolution induced by electromigration occur the
cathode side; at lower critical temperature, voids will form at the cathode
side | en_US |