The Use of Gravure Offset Printing in the Realisation of Fine Line Thick Film Conductors

Abstract

ABSTRACTThe use of gravure offset printing to transfer film patterns from an inked plate to the substrate by a silicone rubber pad has been shown to have promising advantages in fine line and multilayer production. The technology is now moving into the field of electronics manufacturing. By optimising the printing parameters and ink characteristics in the gravure offset technique, lines and spaces as narrow as 50 μtm were achieved and even finer lines are possible. Commercially available fine line thick film Au and Ag pastes were modified for this purpose. The thickness of sintered conductors ranged from about 2 to 11 μtm depending on ink viscosity, control of printing equipment and repetition of prints. When compared with films deposited by conventional thick film technology, the conductivity and adhesion on alumina were similr. The small interconnections between conductors through the insulator layer necessary in multilayer techniques were realised using gravure offset printing to coat excimer laser drilled vias. Interconnection diameters of less than 100 μtm were achieved.