Manufacturing conductive patterns on polymeric substrates: development of a microcontact printing process

Abstract

The integration of high-resolution conductive structures into polymer devices using a low-cost, rapid, and accurate manufacturing technique is important for the future of the microfluidic, photovoltaic, flexible printing, and organic electronics industries. In this study, the microcontact printing (μCP) of high-resolution conductive patterns on polymer substrates using silver nanoparticle inks and a roll-based printing equipment was empirically investigated. A process model was developed to predict the quality of the printed patterns (defined as thickness and coverage ratio) from known printing parameters, based on the statistical analysis of a set of carefully designed experiments that were informed by theoretical understanding of the μCP process. The statistically relevant variables in the process model for the pattern thickness were ink solids loading, ink viscosity, stamp feature size, and the surface energy ratio of ink to substrate. For the coverage model, the key inputs were ink solids loading, ink viscosity, stamp feature size, and inkpad thickness. The effects of these variables on the thickness and coverage of the printed patterns were quantified by a linear model derived from an orthogonal, fractional factorial experimental design with five input factors and two outputs. The extension of the process model to predict the printing behavior of other inks and substrates, and the successful printing of conductive features on polymer substrates with 5 μm resolution, were demonstrated.