Silylation-based techniques are being actively investigated for dielectric recovery after plasma processing of porous ultralow dielectric constant (low k) dielectrics. A two-step pore sealing and dielectric recovery process was attempted on plasma damaged porous organosilicates (OSG). In the sealing step, an OSG low k monomer, phenyltrimethoxysilane, was used to form a thin low k sealant layer. Scanning transmission electron microscopy and transmission electron microscopy images indicated a much improved low k/barrier interface as a result of pore sealing. In the surface silylation step, two phenyl-containing agents, diphenyltetramethyldisilasane and phenyldimethylchlorosilane, were employed to restore surface hydrophobicity. The process was found to be capable of restoring surface hydrophobicity and partially blocking the pathway for moisture adsorption without much adverse effect on the subsequent atomic layer deposition of Cu barrier. (c) 2007 American Vacuum Society.