Abstract: Adhesion of copper to a resin layer is improved by reducing a copper oxide layer with an aqueous aldehyde solution (a) while applying a potential of -1000 mV to -400 mV to the copper oxide layer, (b) after contacting with a metal piece made of copper or a metal nobler than copper, or (c) after contacting with an aqueous solution of alkali borohydride.

Abstract: Crystallized glass roughened by using a roughening solution having a larger dissolving rate as to a non-crystalline phase compared with a crystalline phase, followed by metallizing by electroless plating shows strong adhesive strength between the crystallized glass substrate and the plated film.

Abstract: A metallic film can be formed on a ceramic surface with high adhesive strength by roughening the ceramic surface by (a) dissolving and removing a vitreous substance and (b) roughening a substance constituting mainly a first surface layer, followed by conventional electroless plating.

Abstract: A process for treating a surface of a metal such as copper with a liquid composition comprising (I) copper ions, a complexing agent, a reducing agent, a pH adjusting agent, water, and (II) a nitrogen-containing organic compound such as heterocyclic compound or containing --N.dbd. and --NH.sub.2 and/or --OH groups in its molecule can give multilayer printed wiring boards having excellent adhesive strength and line definition of inner layer copper conductors with long shelf life.

Abstract: An electroless copper plating solution comprising cupric ions, a complexing agent, a reducing agent, a pH adjuster, a perfluoropolyether, a cyanide and/or .alpha.,.alpha.'-dipyridyl and/or 1,10-phenanthroline or a derivative thereof is capable of forming a deposited film with high elongation.

Abstract: An electroless copper deposition solution comprising (a) cupric ions, a complexing agent for cupric ions, a reducing agent and a pH adjusting agent, (b) a polyoxyethylene ether and (c) at least one member selected from the group consisting of an inorganic cyanide and .alpha.,.alpha.'-dipyridyl can give a deposited film with high elongation.

Abstract: A method of improving adhesion between the surface of a substrate and a metal deposit electrolessly plated thereon by forming a novel adhesive material layer comprising (A) a rubber material and (B) a thermosetting resin which is present in a proportion defined by the formula 20.ltoreq.(B)/(A)+(B).ltoreq.85 volume %. In the adhesive layer the thermosetting resin is dispersed, in the form of substantially spherical particles of 0.5 to 15.mu., in the continuous phase of the rubber material. The method is useful for producing printed circuit boards having a high precision and high accuracy pattern circuit. Further, the method is extremely advantageous when it is applied to the so-called photo-forming process since disappearance of the catalyst nuclei on the circuit pattern image can be eliminated.