The first observation of p-type electromigration failure in full ruthenium interconnects

We show the first electromigration (EM) failures of full ruthenium interconnects with a cross sectional area of 60nm
²
. The void is observed at the anode, which demonstrates that in p-type metals, such as Ru, the electromigration force acts in the direction of the electric field. The conventional representation of electromigration as electrons transferring their momentum onto the metal ions, thus has to be adapted for such metals. Moreover, we find that diffusion at the Ru-SiO
2
interface is the dominant diffusion mechanism for EM failure in these specific Ru lines.