Direct imprint of conductive silver patterns using nanosilver particles and UV curable resin

The direct nanoimprinting of device patterns on functional resist has attracted increasing attention since it has the potential to extend nanoimprinting applications and improve productivity. Considerations of device-oriented functional resins are currently limited to optical or optoelectronic applications where the optical properties of the imprint resin can be selectively controlled. Either nanosilver particle dispersions or conductive polymers are candidate resins for the direct imprinting of electrode line patterns. In this paper, we describe direct ultraviolet (UV) imprinting using acrylate-based resin incorporating nanosilver colloid, with optimized post-imprinting steps involving heat treatment and wet etching. Resin mixtures with 40, 50, and 60 wt% of nanosilver loading were prepared, and UV imprinting was performed on the dispensed resin mixtures, followed by heat treatment to sinter the nanosilver particles and wet etching of the imprint residues. The pattern shrinkage that occurred during the post-imprinting steps reached 25-35%, and was strongly dependant on the nanosilver concentration. The electrical resistivity for 60 wt% Ag loading was roughly 2.5 times higher than that of bulk silver. In addition, surface texturing effects on the imprinted patterns were investigated using selective oxygen plasma etching. (C) 2009 Elsevier B.V. All rights reserved.