Direct deposition of thick film pastes to form fine line patterns

Direct writing (DW) means a method used for direct deposition of thick film or polymer paste on a substrate to form electrical circuits together with their elements (conductors, inductors, or resistors such as shielding etc.). It is a non-vacuum process, fully compatible with standard thick film technology that enables us to create thick film patterns directly on the substrate without using a photoresistive process. The aim of this study is to examine and verify the possibility to construct a simple writing deposition equipment that would be able to provide repeatable and reliable process deposition. The developed equipment is controlled by a computer automated unit that enables precision printing of non-diluted screen printing pastes. The pattern is drawn on the substrate by a non-contact nozzle which is fixed in the dispensing unit. Its movement is controlled by x, y, z axis table. This procedure was chosen as a low cost alternative to deposition of fine line thick film pastes, e.g. in hybrid IC's, but especially in other nonconventional applications, such as the front sides of solar cells, biosensors etc. The pastes were deposited on Al₂O₃ substrate, fired and then various parameters were measured.