Printing Contractive Silver Conductive Inks Using Interface Interactions to Overcome Dewetting

Abstract

Surface energy incompatibility between ink and substrate is a significant obstacle for inkjet printing of electronic components, causing printed lines to dewet and break apart. In this paper, it was demonstrated that smooth, continuous silver lines could be printed via control of ink-substrate interactions, despite the tendency of the ink to dewet from the substrate. The silver lines were printed using drop-on-demand inkjet printing of silver nanoparticle ink onto non-crosslinked SU-8 coated polyethylene terephthalate (PET). The lines were subsequently heated to control dewetting and cause contraction from $60~\mu \text{m}$ to $14~\mu \text{m}$ . The SU-8 film underneath the silver line was dissolved and redistributed to form a ridged concave structure that prevented the lines from bulging and breaking apart. Additionally, photonic sintering was used to achieve low resistivity of $0.06~{\mu } {\Omega }\text{m}$ for the narrow printed lines.