Method for the manufacture of high quality gravure plates for printing fine line electrical circuits

Electrical thick film circuits have, up to now, been printed with screen printing. This technology and PCB-processing technology are well known and widely used in commercial production. In conventional screen printing and PCB-technology, the accuracy limit is at about 150 microns. The tendency towards higher packing densities requires smaller dimensions to be printed. Therefore, a gravure offset printing process for electronic circuitry is under development. One important task in printing process development is the requirement for high quality and accurate gravure plates. In conventional pad printing, etching, laser engraving and photopolymer methods are the processes mainly used for gravure plate making. For the production of high quality and accurate gravure plates, a new process has been developed. A grooved gravure plate is electrodeposited on a substrate upon which a photoresist pattern has been formed. After electrodeposition, the plate is peeled from the substrate. There are several advantages over the existing process. The surfaces of the grooves so formed are smooth. The depth of the grooves can be accurately controlled because it is the same as the thickness of the applied resist layer. Grooves deep enough to transfer sufficient ink needed for the electrical circuit patterns may be realised.