(383f) Capillary-Based Liquid Micro/Nano Deposition
Micro/Nanolithography is a creation of micro/nano features on the substrate. Several lithography techniques have been recently developed, including dip-pen nanolithography, nano-imprint lithography, electron-beam lithography, and photolithography. However, all these techniques possess some limitations due to a direct contact with the substrate. This paper proposes a new capillary-based lithography method that is non-invasive to substrate. The application of the pressure from one side of capillary causes the liquid meniscus to form at the capillary outlet. Touching the substrate with the meniscus only causes the liquid deposition on the substrate. Theoretical modeling reveals two possible regimes: stable liquid bridge formation – “good” bridge; and unstable liquid bridge formation – “bad” bridge. The size of deposited liquid droplet is in the range of 15% of inner diameter of the capillary and weekly depends on capillary retraction speed. Glycerol was chosen as trial liquid of deposition, because glycerol rate of evaporation is low in comparison with other liquids. Deposition of glycerol-water mixture was done in micro-scale for various diameters of the capillary and fluid viscosity. Numerical Boundary Element Method code was developed to simulate liquid bridge dynamics during capillary retraction. Comparison of theoretical results with experimental data is shown and discussed. To scale this method down to nanoscale the gold-coated nanocapillary attached to the Scanning Tunneling Microscope was used. This research brings a better understanding of the physics and mechanics of liquid deposition and has the potential of finding application in biotechnology. This material is based on research sponsored by the Defense Microelectronics Activity (DMEA) under agreement H94003-09-2-0905, North Dakota EPSCoR and National Science Foundation grant number EPS-0814442.