Studies on inkjet-printed conducting lines for electronic devices

Inkjet printing is considered one of the most promising methods for patterning and materials deposition. The feasibility of employing inkjet technology for the creation of conductive pathways on printed circuit boards is addressed herein. Prediction of the width, length, and thickness of printed lines as a function of the dot diameter, resolution, and volume fraction of the particles in the ink is presented. Surface treatment of the substrate to promote desirable adhesion and wetting properties as well as the adjustment of the curing process to reduce the surface roughness of the printed traces were studied. In a sintering study, samples sintered at 250 degrees C for 20 min showed a resistivity of 4.2 mu ohm cm, which is approximately 2.6 times that of bulk silver. A low-temperature sintering method through the reduction of a metal salt is presented. The resistivity of printed samples sintered at 140 degrees C for 30 min in the presence of silver nitrate with N,N-dimethylformamide showed a resistivity of 22.5 mu ohm cm.