Perstorp Ab

Jiri K Konicek

Hans R Malm

Kjell A Cederberg

Peter J Nilsson

In a process for the production of a multilayer printed board built up by starting from a desired number of insulating bases clad on both sides with an unpatterned metal layer, the improvement consisting in that the metal layers, whereout conductive patterns are to be etched and which layers are to be hidden inside the finished multilayer printed board, are coated with a plating resist in the shape of a negative of the desired conductive pattern, that the remaining visible parts of the metal layers, which are to form the conductive patterns, are coated by electroplating with a thin, rough, adhesion-promoting metal layer comprising copper, zinc, nickel, tin or any one of their alloys, that an etch resist layer of nickel, tin or any one of their alloys is electroplated on top of the adhesion-promoting layer, if the latter consists of copper, zinc or any one of their alloys, that the negative plating resist is removed, that the parts of the metal layers thus uncovered are etched away and that the insulating bases provided with conductive patterns are laminated to a multilayer printed board.

Process in the production of a multilayer printed board

A method for the production of through holes in a laminate comprising an insulating base provided with a thin metal layer on at least one side, said laminate being intended for printed wiring. The method is characterized in that the thin metal layer is provided with a firmly adhering and protective foil or layer of a material being chemically different from the thin metal layer and that so-called burrs in the thin metal layer obtained during a mechanical machining of the holes are removed by dissolution whereupon the protective foil or layer can be removed.

Method for the production of through holes in a laminate

A method for the production of a material for printed circuits is disclosed. A temporary base is coated by electroplating with a thin, unbroken and unpatterned metallic layer having a thickness less than 17.mu.m and the free surface of said metallic layer is bonded to a final insulating base. The temporary base is thereafter removed and the desired wiring pattern is produced by a process comprising etching of the metal layer. A material for use in production of printed circuits is also disclosed comprising a temporary base which is coated by electroplating with a thin, unbroken and unpatterned metal layer having a thickness less than 17.mu.m. Said material can comprise a final, insulating base bonded to the free surface of the thin metal layer.

Method for the production of material for printed circuits

A method for the production of a material for printed circuits is disclosed. A temporary base is coated by electroplating with a thin, unbroken and unpatterned metallic layer having a thickness less than 17 .mu.m and the free surface of said metallic layer is bonded to a final insulating base. The temporary base is thereafter removed and the desired wiring pattern is produced by a process comprising etching of the metal layer. A material for use in production of printed circuits is also disclosed comprising a temporary base which is coated by electroplating with a thin, unbroken and unpatterned metal layer having a thickness less than 17 .mu.m. Said material can comprise a final, insulating base bonded to the free surface of the thin metal layer. The temporary base may be comprised of an aluminum foil coated with a layer of zinc or an aluminum foil to which has been applied zinc and which has the zinc replaced electrochemically by half or partly, by a layer of a metal which is more electro-positive than the metal zinc. In electroplating a thin, unbroken and unpatterned metallic layer onto the temporary base the electroplating takes place in a solution containing copper, pryophosphate and an acid, the pK-value of which is at least 0.8 at 20.degree.C.

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Perstorp, Sweden

Jiri K Konicek