This article describes the results of complex studies of the mechanism of sensitization and activation processes before electroless plating of piezo and dielectric materials. The results of electroless metallization investigation are presented which enable us to carry out the microminiaturization of electronic devices and to increase their reliability. Principal results of the studies aimed at revealing the process of adsorption of tin and palladium ions have been obtained using the methods of radioactive isotopes and X-ray photoelectron spectroscopy. The mechanism of sensitization and activation is established The developed technologies are used in space and computer engineering, electronics, and as a result, the use of gold and silver has been adequately substituted by alloys of non-precious metals, and toxic electrolytes are eliminated. The proposed method is much more advantageous and simple than other expensive and complicated methods of condensation at vacuum-thermal evaporation, sputtering, deposition from vapour gas mixtures and high-temperature burning of metal-containing pastes. The elaborated technological process of microfabrication and new construction of selectively semitransparent photomasks avoid problems of contact photolithography, guarantee the high alignment precision and have many advantages.