| abstract |
A method for making a thin film printed board precursor containing a laminate of a controlled-flow dielectric thermosetting resin film layer and a heat and electrically conductive metal foil layer in direct adhesive bonding with a side of the resin film, optionally containing a supporting layer comprising one or more of fiber, fabric and thermoplastic polymer in contact with the other side of the resin layer, wherein the dielectric thermosetting resin layer has an unimpeded thickness that is at least equal to that of the foil layer bonded to it. The method comprises adhesively bonding an electrically conductive metal foil layer to a dielectric thermosetting resin film layer that has said unimpeded thickness. The laminate may be debossed through the metal foil layer and into the dielectric thermosetting resin film layer with a tool containing a raised electrical circuit pattern thereon. This step involves impressing the tool onto the foil layer surface thereby causing the foil layer to impress into the unimpeded thickness of the thermosetting resin layer and retaining one or more of a debossed and embossed pattern in the metal foil and the attached resin film that is complementary to the raised electrical circuit pattern on the tool. The debossed laminate is subjected to conditions that effect one of near-gelation, gelation and cure of the attached resin film and fixes the retained pattern in the metal foil layer and the resin layer of the laminate. |