Nanoprinting of Metallic Conductive Inks with Fountain Pen Nanolithography

Printing of conductive metallic lines with widths as small as 15 nm can be controlled up to a few µm by using Fountain Pen Nanolithography (FPN). The FPN technique is based on a force sensing bent nanopipette and the printing with force feedback is similar to a pen in the nano regime. The geometry of the nanopen and atomic force microscopy system used allows the placement of the printing tip with the highest of optical resolutions. Any desired location can be rapidly accessed with sub-micrometer precision. Using this nanopen, investigations of various inks were undertaken together with instrumental and script-tool development. This led to the printing of conductive lines using inks composed of silver nanoparticles and salt solutions of silver and copper. In addition, it is shown that printing over structures with varying heights and material characteristics is achievable without changing the line dimensions. The line widths are varied by using nanopens with different orifices or by tailoring wetting properties of the ink on the substrate. Metallic interconnections of conducting lines are reported with a conductivity of up to 0.45% of bulk silver. The results demonstrate both conductive lines and electrical interconnections can be printed at scales presently not being addressed.