Diffusion barrier properties of carboxyl- and amine-terminated molecular nanolayers

Molecular nanolayers are attractive for preserving the integrity of Cu-dielectric interface in sub-50nm interconnect structures. Here, we demonstrate the use of carboxyl- and amine-terminated self-assembled molecular layers (SAMs) to immobilize Cu at the Cu∕SiO2 interface. Amine-terminated SAMs at the Cu∕SiO2 interface increase the Cu diffusion-induced device failure time by a factor of 3 compared to interfaces without a barrier. Carboxyl-terminated SAMs obtained by grafting succinyl chloride onto the amine-terminated SAM show more than an additional factor of 4 increase in failure time. Coordination complex formation though strong interactions between COOH and Cu+ at the Cu∕SAM interface is the likely reason for the effective immobilization of Cu.