Process for the partial metallization of substrate surfaces

In a process for the manufacture of printed circuit by electrolessly partially metallising of a substrate surface wherein

• (a) the substrate surface is wetted with a solution or a grinding paste of silver(I) compounds which are photosensitive in the solid state said solution or grinding paste being essentially free of film-forming and other polymeric substances,
• (b) the solvent is removed,
• (c) the silver(I) compounds remaining on the substrate surface are partially exposed,
• (d) the unexposed silver(I) compounds are detached from the substrate surfaces and
• (e) the thus obtained substrate surface is treated with an electroless metallising bath containing nickel salts, cobalt salts or copper salts the improvement wherein said silver(I) compounds are sparingly soluble in said solvent and are converted into a soluble form by means of complexing agents, the surfaces to be partially metallised are wetted with the solution of the latter and the complex compounds left behind on the surface are split up again into the photosensitive sparingly soluble compounds and wherein said sparingly soluble compounds and wherein said sparingly soluble silver(I) compounds are silver salts of an acid selected from the group consisting of formic acid, acetic acid, propionic acid, glycolic acid, lactic acid, oxalic acid, malonic acid, citric acid, adipic acid, benzoic acid, salicyclic acid, hippuric acid, pyroterebic acid, phenols, enols sulphonic acids and sulphinic acids.