Micrometer to 15 nm Printing of Metallic Inks with Fountain Pen Nanolithography

The field of printed electronics is continually trying to reduce the dimensions of the electrical components. Here, a method of printing metallic lines with widths as small as 15 nm and up to a few µm using Fountain Pen Nanolithography (FPN) is shown. The FPN technique is based on a bent nanopipette with atomic force feedback that acts similar to a nanopen. The geometry of the nanopen allows for rapid placement accuracy of the printing tip, on any desired location, with the highest of optical sub-micrometer resolution. Using this nanopen, investigations of various inks were undertaken together with instrumental and script-tool development that allows accurate printing of multiple layers. This has 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 the method can be applied to substrates of various materials with minimal effect on the dimension of the line. The line widths are varied by using nanopens with different orifices or by tailoring the 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.