Abstract: An activated substrate surface suitable for electronics and microsystems preparation is prepare by contacting the surface with a surface activation compound, e.g. organometallic based on palladium, platinum, rhodium or iridium. The photo labile ligand has an optical absorption band which overlaps with the wavelength of the UV. A UV lamp is used, in combination with a mask, to selectively irradiate the contacted surface. Irradiation of the surface with light of a suitable wavelength decomposes the organometallic compound to the activating metal. The surface is then ready for electroless plating with the desired conducting material. The mask is patterned to delineate areas where surface activation is not to occur. The organometallic compound absorbs ultraviolet radiation in the wavelength range 210-260 nm, or in the wavelength range 290-330 nm, in the solid state if the compound exists as a solid at 25° C. or in the liquid state if the compound exists as a liquid at 25° C.