Ultralow-k dielectrics are mainly porous and pose reliability issues as copper barrier integrity is compromised on porous surfaces. No work is reported on use of self-assembled monolayers (SAMs) as Cu diffusion barrier or to seal pores for ultralow-k dielectrics. We attached SAMs to ultralow-k film and confirmed by analytical techniques such as Auger and X-ray photoelectron spectroscopic analysis. We report reduction of leakage current and enhancement of dielectric breakdown voltage of the ultralow-k p-SiLK film after SAM attachment showing it to be a promising barrier material for prevention of Cu diffusion. H-2/N-2 plasma treated p-SiLK film showed early breakdown and high leakage in spite of SAM attachment. (c) 2006 The Electrochemical Society.