| 摘要 |
Production of multi-layered electrical circuit boards which have closely spaced circuit elements is accomplished by applying a solder-resistant lacquer coating to the outside surfaces of a plurality of conductor plates affixed together in juxtaposed relationship, producing bores through the plurality of circuit boards in a predetermined relationship to their circuitry placed thereon, depositing a first copper layer by currentless means upon the bore wall and the solder-resistant lacquer coated surface, applying a galvanic-proof coating to the copper metal layer in predetermined areas leaving soldering eyes free of the galvanic-proof coating, galvanically coating the bores inclusive of the soldering eyes with a second copper reinforcing layer, applying an etch-proof metal layer on the surface of said copper reinforcing layer, removing the galvanic-proof lacquer layer and the first copper layer by etching on the places not covered by the etch-proof metal layer. |
