Corona Treatment for High-Throughput, Layer-by-Layer Nano-Transfer Molding
Michael Deagan, Edwin Chan, Linda S. Schadler, Chaitanya Ullal
Corona discharge treatment offers a facile, robust, and scalable technique for adhesion promotion in nano-transfer molding. In contrast to conventional plasma treatment, which requires vacuum operation, corona treatment at ambient pressure enabled patterning of woodpile structures of PDMS with smaller feature dimensions (70 nm linewidth) and across a wider range of treatment doses. We correlated plasma and corona treatments as batch and continuous processes, respectively, by evaluating the spatiotemporal evolution of wettability through dyne tests. Both types of treatment formed surface films of oxidized PDMS that were characterized by uniaxial compressive buckling of the PDMS-oxide bilayer. Corona treatment, by forming a thinner oxide film, extends the range of treatment doses and feature sizes that lead to successful pattern transfer. Reduction in adhesion at high treatment dose is attributed to a weak boundary layer at the bondedinterface. Demolding peel tests and AFM analysis revealed that both plasma and corona treatment etch the stamp material (PFPE), underscoring the benefits of low treatment dose for process throughput as well as stamp lifetime. While both treatments displayed comparable etch rates as a function of dose, microscopic bumps on corona- etched stamps suggest a higher surface temperature compared to plasma-etched stamps. By optimizing adhesion for nano-transfer molding with a surface treatment well-suited to continuous processing, corona treatment provides a practical and economical approach to layer-by-layer additive manufacturing at the nanoscale.
, Chan, E.
, Schadler, L.
and Ullal, C.
Corona Treatment for High-Throughput, Layer-by-Layer Nano-Transfer Molding, ACS Applied Materials and Interfaces, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=927364
(Accessed May 28, 2023)