Study of electromigration void nucleation time in Cu interconnects with doping elements
This study shows that in Cu interconnects with different doping elements (e.g., Al, Co, Mn) electromigration failure times may be significantly increased because of an incubation time prior to the usual void formation. The presence of a significant incubation time provides a change from the common value of 1 to a value of 2 of the current exponent of Blacks equation, mostly used for lifetime extrapolation at use conditions. Moreover, an increase of the activation energy up to 1.4eV has been experimentally obtained. This gives additional room for reliability lifetime extension.
electromigration void nucleation cu interconnects void growth