Abstract: A process is disclosed for forming resistors on a printed circuit substrate. The method includes the step of applying a photoresist layer onto substrate, and forming openings in the photoresist layer to expose the preselected regions for resistors, such that polymer thick resist pastes as well as resistive metallic films can be applied onto the substrate through these openings with precise geometry. The process according to the invention has higher accuracy and greater processing flexibility than the prior art processes where the resistor pastes are directly applied onto the substrate by screen printing.

Abstract: Polymer thick film resistor pastes with dimensionally stability and excellent processibility, such as coating, printing, and extruding, are disclosed. The resistor paste composition in accordance with the present invention comprises a low-k cycloaliphatic epoxy resin vehicle loaded with electrically conductive particles, a cationic photoinitiator, a thermal catalyst, and optionally a reactive diluent.