Methods of discouraging poreseal deposition on metal (e.g. copper) at the bottom of a via during a poresealing process are described. A self-assembled monolayer (SAM) is selectively formed on the exposed metal surface and prevents or discourages formation of poreseal on the metal. The SAM is selectively formed by exposing a patterned substrate to a SAM molecule which preferentially binds to exposed metal surfaces rather than exposed dielectric surfaces. The selected SAM molecules tend to not bind to low-k films. The SAM and SAM molecule are also chosen so the SAM tolerates subsequent processing at relatively high processing temperatures above 140° C. or 160° C. Aliphatic or aromatic SAM molecules with thiol head moieties may be used to form the SAM.