Published online by Cambridge University Press: 10 February 2011
We describe a new technique for making copper lines by printing a precursor pattern that is converted to copper, at a maximum process temperature of 200°C. We formed copper metallization patterns on 80 μm thick Coming 0211 glass substrates by jet printing. Continuous lines of copper with resistivity of 10 μΩcm have been obtained. We successfully applied this technique to the direct printing of copper source and drain contacts for amorphous silicon thinfilm transistors. The TFTs are bottom gate back-channel etched structures, with the silicon stack made by RF excited PE-CVD. The TFT process uses only printing for all masking steps, by employing laser-printed toner etch masks, and using the printed copper as the mask for the back channel etch. The transistor ON/OFF current ratio is 105. The process for copper printing represents a further step toward an all-printed TFT technology.