Sep 9, 2009
Polymer trenches preserve pattern resolution
Solution printing methods such as ink-jet printing, screen printing and microcontact printing have gained considerable attention as a way of fabricating metallic wires at the microscale. They do not require expensive high-vacuum systems and thanks to the direct nature of the patterning process, they also use less organic solvent and less toxic material than conventional microfabrication methods based on photolithography.
Unfortunately, the ink-like solutions of metallic nanoparticles can diffuse or spread over the substrate surface, which makes fine pattern resolution more difficult to achieve.
To overcome this problem, researchers from the Advanced Lithography for Integrated Systems Lab. (ALIS) at Gwangju Institute of Science and Technology (GIST) have come up with an alternative approach for fabricating metallic wires at the nanoscale. Their method involves using a nanoparticle solution in combination with nanoimprint lithography.
Nanoimprint lithography was chosen due to the ease of preparation of polymer templates at the nanoscale. The nanoimprinted polymer templates provide a physical reservoir for confining the ink and prevent the mixture from diffusing across the substrate as mentioned above.
A simple spin-coating method is used to fill the polymer trenches with a solution of metal nanoparticles, which is then annealed to improve the conductivity of the metallic wire after lift off.
All of the fabrication steps are achieved at a low temperature and at atmospheric pressure, which opens up further possibilities for the processing of plastic electronics.
The researchers presented their work in Nanotechnology.
About the authors
This research was partially supported by the Korea Research Foundation funded by the Korean government and the Program for Integrated System (PIMS) at GIST. Eun-UK Kim was a masters degree student and is currently working for the Kolon central research park as a researcher. Professor Gun-Young Jung is leading the ALIS group, which is implementing lithography techniques into active devices such as semiconducting light emitting diodes, solar cells, and nonvolatile memory devices. The team has already demonstrated 17 nm half-pitch metal nanowires using nanoimprint lithography techniques.