Keun-Ho Kim
Ph.D. Candidate, Department of Mechanical Engineering, Northwestern University, USA
Advanced Tool for Dip-Pen Nanolithography - Nano-Fountain Pen
Novel atomic force microscopy (AFM) probes were developed to expand the
capability and applications of dip-pen nanolithography (DPN) technology.
Using AFM tips, chemical ink can be deposited by DPN with a line-width
resolution of less than 20 nm. However, in DPN techniques, inks need to be
replenished periodically, which requires dismounting the AFM probe. A new
novel AFM probe has been developed which can continuously feed ink without
interrupting the DPN process. This new probe has integrated microchannels
and reservoirs, which allow "fountain-pen" writing to enable fountain pen
nanolithography (FPN). Ink is transported from the reservoir through
embedded microchannels and eventually dispensed onto substrates via a
volcano-shape dispensing tip. Numerical simulations have been performed to
select optimal materials and suitable tip shapes providing stable fluid-air
interface in the writing tip. Microchannels and volcano tips have been
produced by surface micromachining technology, specifically, employing three
stacked layers of film. Fluid flow through the microchannels has been tested
using water-soluble fluorescence dye. Imaging capabilities comparable to
commercial AFM probes have been validated. Also, preliminary fountain-pen
mode writing has been examined. The proposed FPN device will be arrayed and
actively actuated to accomplish nanolithography in a massively parallel way.
