Abstract: A method of activating a non-conductive substrate for use in electroless deposition is proposed, in which an aqueous solution containing nanoparticles of noble metals and their alloys is used as an activation solution in an electroless plating process, so as to electrolessly deposit a conductive metal deposition on the substrate and into micrometer-sized trenches formed on the substrate. By using this method with provision of a solution of a copper or nickel salt, copper or nickel can be deposited on the non-conductive substrate, allowing high aspect-ratio trenches on the substrate to be filled with copper or nickel for subsequent use in fabrication of integrated circuit interconnection.