Size Effect On The Electron Wind Force For Electromigration At The Top Metal-Dielectric Interface In Nanoscale Interconnects

We report a classical model on the size effect of the electron wind force on a metal atom at the metal-dielectric interface in nanoscale interconnects. The effect is expressed as a size factor S for the effective charge Z*e. It is found that the size factor decreases with scaling due to reduced electron drift momentum as a result of scattering at interfaces and grain boundaries. The electron wind force on the metal atoms at the top metal-dielectric interface is enhanced by the interface scattering. This force enhancement is partially mitigated by the grain boundary scattering. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4750067]