Microcontact printing, polymer pen lithography, and their variations have attracted interests from a broad spectrum of research fields as a result of the feasibility of defining patterns in micro- and nanoscales. In this work, we have proposed and demonstrated a novel lithography method, named plasma-assisted microcontact printing (PA-μCP). Unlike the previous printing methods, where a direct contact is normally required for the transport of liquid-phase inks, plasma-deposited fluorocarbon (FC) has been employed in PA-μCP as the ink material, which can be transferred from the stamp to substrates through a thermal evaporation process. The geometry of the patterns can be modified by adjusting the design of stamp patterns and the contact time, and transferred FC patterns can be used directly as an etch mask to create microstructures in the substrate materials. We have demonstrated the possibility of performing multi-patterning with PA-μCP, where FC patterns can be generated conformally on structured substrates. Because the height of FC patterns is closely related to the local pattern designs, PA-μCP can be used for grayscale patterning. As a proof of concept, Fabry-Perot planar cavities are fabricated with grayscale PA-μCP for structure color printing. We believe PA-μCP is distinguished from conventional techniques by its printing mechanism, which can pave the way for convenient fabrication of photonic, electronic, and biological devices.
Keywords: fluorocarbon; grayscale lithography; microcontact printing; plasma treatment; structural colors.