Patent ID: 6952871

Claim:
A manufacturing process for printed circuit boards of the type comprising the following steps: making a first selective engraving over a first face ( 10 a ) of a panel ( 10 ) of electro-conducting material to form reliefs ( 12 ) corresponding to future tracks and depressions ( 14 ) corresponding to future intermediate tracks; applying by injection moulding a dielectric material 20 over said first face ( 10 a ) of the panel ( 10 ) of electro-conducting material, covering said reliefs ( 12 ) and filling said depressions ( 14 ); and, making a second selective engraving over a second phase ( 10 b ) opposite to the first one of the mentioned panel ( 10 ) of electro-conducting material to eliminate the material thereof, corresponding to said future intermediate tracks, so that some finished tracks ( 16 ) remain, isolated from each other, separated by intermediate tracks ( 18 ) and partially embedded over a face of said dielectric material ( 20 ), characterised in that, after the first engraving stage and before said injection moulding stage, it also comprises the following stages: subjecting said previously engraved first face ( 10 a ) of the panel ( 10 ) of electro-conducting material to a surface treatment improving the joining capacity which comprises a black oxide operation consisting of placing said first face ( 10 a ) of the panel ( 10 ) of electro-conducting material in contact with an aqueous solution of sodium hydroxide and sodium hypochlorite producing a chemical micro-attack to provide a determined surface roughness; and applying a layer of adhesive material ( 30 ) over said engraved and superficially treated first face ( 10 a ) of the panel ( 10 ) of electro-conducting material.