The practical and widespread implementation of nanotechnology requires precise three-dimensional arrangement of functional materials. There is significant demand for an inkjet printer that can print structures with complex topologies. To meet this demand Japan’s National Institute of Advanced Industrial Science and Technology (AIST) has successfully developed a super-fine inkjet printer, which can discharge micro ink droplets, far smaller than those of normal inkjet printers. To allow widespread use of this technology, AIST has designed a portable unit that is about 600 times smaller than the first generation SIJ printer and fits in the palm of a hand. By using this ultra-small SIJ units, micrometer scale patterning or precise material deposition in the femtoliter order is feasible. Mask-less patterning, such as micrometer scale circuit pattern can be achieved without the photolithographic process.
Photo: AIST Palm Sized Superfine Inkjet Printer and Original Superfine Inkjet Printer
Credit AIST
Superfine inkjet technology developed at AIST’s Nanotechnology Research Institute is being commercialized by SIJ Technology, Inc, an AIST spin-off company. The technology allows the ejection of super-fine liquid droplets smaller than the conventional droplets ejected by a home-use conventional inkjet printer. The revolutionary autonomous ink-jet method developed by Dr. K.Murata, NRI, AIST allows production and arrangements of dots with a minimum size of less than one micron, which corresponds to sub-femtoliter units in volume. This volume corresponds to a 1/1000 of the volume of the dots dispensed using the ink-jet devices currently on the market, which places this technology at the top of circuit printing technologies in the world
The super-fine inkjet technology developed by the Nanotechnology Research Institute of AIST allows the ejection of super-fine droplets much smaller than the conventional droplets ejected by a conventional inkjet printer-at least 1/10 smaller in size and 1/1000 smaller in volume.
Credit: SIJ Technology Inc.
SIJ Technology, Inc. is engaged in the research and development with AIST and Harima Chemical to commericialize super-fine inkjet technology. Using this newly developed technology, the team has confirmed that diverse materials such as nanotubes, electroconductive polymers and ceramics can be used as solutes for the ink. At the same time, tests using NanoPaste®, stable dispersion of metal particles developed by Harima Chemicals, have been carried out, resulting in successful circuit printing on diverse substrates such as glass or polyimide. This result shows that it is possible to directly print ultrafine metallic wire of only a few microns in width.
Figure: Using NanoPaste® to Draw a Super-Fine Wiring Pattern
Credit: SIJ Technology Inc.
This technology can be applied not only to surface mounting related technologies but also to innovative applications in other nanotechnology fields such as biotechnology, optical and ultrafine processing technologies. Harima and AIST have filed U.S. Patent Application 20060286301 to protect NanoPaste® compositions and superfine inkjet technology.
An interesting aspect to metals is that for particles smaller than 20 nm in diameter, the effective melting point decreases dramatically. For example, the melting point of a super-fine silver particle may be as low as room temperature, whereas a micron sized particle of silver melts at 961ºC.
Using a solution with these nano-size particles as ink, with out novel printer, enables maskless patterning with a line width of several microns, which is comparable to the photolithographic methods, but at room temperature and normal atmospheric pressure.
Because super-fine liquid droplets dry very quickly, the droplets can be accumulated to form a three-dimensional structure by shooting them at a fixed target.
Figure: Forming a three-dimensional structure.
Credit SIJ Technology Inc.
Credit: AIST
