New thick-film copper paste for ultra-fine-line circuits

Key technologies for processing of a thick-film copper conductor applicable to photolithographic techniques are described. A flexo printer was used to obtain a film of less than 2-μm thickness on a substrate. Using photolithographic techniques, fine-line circuits with 40-μm-wide copper conductor lines were realized using copper pastes doped with chalcogens. Dense thin films and good adhesion to the substrate were achieved by doping chalcogens from 0.01 to 0.05 wt.%. Characteristics of these conductor films satisfied the standard requirements for hybrid ICs