Kollmorgen Technologies Corporation

Fritz Stahl

Horst Steffen

The present invention relates to a semi-additive or full-additive process for producing printed circuit or conductor boards having improved electrical resistance in which the coating of adhesive medium exposed between the trains of conductors is removed or partially removed without corroding the base material or copper of the conductor trains by a treatment with an alkaline permanganate or chromic acid solution and suitable washing steps carried out subsequently.

Method of producing printed circuit boards

A method for producing printed circuit boards with holes having walls provided with a metal coating on base material provided with an adhesive layer which, in turn, is covered by a masking foil composed of plastic material or metal. Following the preparation of the pattern of holes and prior to the removal of the masking foil, the layer of adhesive coating is removed at the edges of the holes by chemical action, so that an annular zone free of adhesive is formed underneath the masking foil. The masking foil is subsequently removed and the metallization of the pattern of conductors and walls of the holes is produced by currentless deposition alone or combined with galvanic precipitation.

Method for producing printed circuit boards with punched holes having

Metal-complex compounds suitable for use in the electroless deposition of said metal are formed in aqueous solution by a method which comprises providing an aqueous solution of the complexing agent, immersing in the solution at least one anode comprising the metal to be deposited and at least one cathode, the anode and cathode being connected to an adjustable current source, applying a current to the anode and cathode to create a voltage difference therebetween which is sufficient to dissolve metal from the anode into the aqueous solution of the complexing agent and thereby form a compound of the metal and complexing agent, and depositing a lesser amount of metal from solution onto the cathode to enrich the solution in the metal-complex compound. In other embodiments of the invention, devices for carrying out the process are also provided.

Process and device for the production of metal-complex compounds

There is provided an improvement in the method of preparing printed circuit boards by chemically catalyzing the surface of an insulating material, electrolessly depositing a layer of copper thereon, masking selected areas of the copper layer not correspnding to the desired pattern of conductor lines, electrolytically depositing additional copper on the unmasked areas, removing the masking material and etching away the copper from the previously masked areas. The improvement comprises the steps of forming an etch-resistant protective layer of oxide on the surface of the electrolytically deposited copper layer before removing the masking material, then removing the masking material and etching away the electrolessly deposited copper from the previously masked areas.

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Am Kehn, Germany

Fritz Stahl