| AVS 61st International Symposium & Exhibition | |
| MEMS and NEMS | Wednesday Sessions |
| Session MN+PS-WeA |
| Session: | Emerging Materials and Fabrication Technologies for MEMS/NEMS |
| Presenter: | Edwin Burwell, Case Western Reserve University |
| Authors: | E. Burwell, Case Western Reserve University A.C. Barnes, Case Western Reserve University P.X.-L. Feng, Case Western Reserve University M. Sankaran, Case Western Reserve University C.A. Zorman, Case Western Reserve University |
| Correspondent: | Click to Email |
Patterning metal as a contact or interconnect is a critical processing step for device fabrication in a wide range of applications ranging from conventional electronics on silicon chips to implantable biosensors on flexible polymeric substrates. Traditionally, physical vapor deposition is combined with photolithography to deposit patterned metal films. Although this subtractive approach produces high pattern fidelity and conductivity, low throughput, materials wastage, and need for vacuum lead to high production costs and limited scalability. The emergence of flexible devices has stimulated the desire for additive approaches such as ink-jet printing for depositing patterned conductive materials. Ink-based printing is carried under ambient conditions and can be integrated with roll-to-roll systems for large-scale manufacturing. However, the inks can be expensive and the variety of materials that are available as printable inks is very small. In addition, the organic capping agents that are used to stabilize the particles are difficult to remove, which can compromise conductivity and mechanical integrity. Removal of the organics requires high annealing temperatures that limit the usage of certain polymers and other temperature-sensitive substrates. Adhesion of the printed structures to the substrates can also be a significant issue, especially in flexible applications.
In this paper, we describe a microplasma-based process to deposit patterned structures with micro- to nanoscale dimensions on rigid or flexible conducting and insulating substrates. This direct-write, additive process uses plasma-based sputtering to generate a physical vapor comprised of the material of interest. The plasma is generated within a small capillary tube that is capped with a micron-sized orifice. The sputtering target consisting of a micron-sized wire is positioned inside the capillary. Forced Ar flow aids in the ejection of the resulting physical vapor through the orifice, which is positioned in close proximity to the substrate. The process is performed at atmospheric pressure, thereby addressing the most significant limitation associated with conventional magnetron sputtering and thermal evaporation, and is low temperature, allowing deposition on temperature-sensitive substrates such as polymers and paper. To date, we have successfully deposited patterned Au structures that are submicron in thickness and 150 microns in width on glass substrates. Our presentation will detail the apparatus, the principal of operation, and the most current results in creating and characterizing micropatterned metal structures on insulating substrates.