The research project investigates a new process for the low-temperature printing and curing of thin gold lines, using nanoparticle slurry microdeposition (printing) and laser heating (curing). This hybrid microprinting and laser curing method will be used for the fabrication of conductors in electronic circuits. The main physical phenomena involve nanoparticle melting and bonding in the presence of the liquid carrier evaporation under the influence of laser radiation. The process is mediated by the spreading of the printed droplets on the substrate and by the dynamic evolution of the capillary flow. A methodology will be developed for writing high electrical conductivity microlines on flexible polymer substrates. On-line diagnostics will be implemented for monitoring and optimizing the dynamic evolution of the process. Theoretical analysis and numerical computations of the thermophysical transport in the droplet spreading, of the solvent evaporation and nanoparticle bonding will be conducted. The mechanics of the nanoparticle bonding will be investigated by time-resolved, near-field-optical scanning microscopy (NSOM) experimental diagnostics.
The research will establish the scientific basis for a host of novel technologies utilizing the unique thermophysical properties of nanoparticle materials. Specifically, the complex thermofluidic transport phenomena in the microprinting, the laser-assisted curing of nanoparticle suspensions and nanoparticle bonding processes will be understood via an array of new experiments coupled with detailed computations.
The technology developed in this project will be utilized to build interconnections in electronics on flexible substrates, including the manufacture of flat panel displays, crossover conductors, capacitors and antennae. Fine features for the fabrication of functional micro-components will be achieved by applying highly localized and pulsed laser radiation. The direct writing of three-dimensional conducting microstructures, as well as rapid prototyping and microfabrication processes that take advantage of this technology will be pursued. The research findings will be incorporated into coursework, a formal seminar and a workshop.
This research has been jointly funded by the Thermal Transport and Thermal Processing Program of the Division of Chemical and Transport Processes and the Nanomanufacturing Program of the Division of Design, Manufacturing and Industrial Innovation.
