AVS 47th International Symposium
    Processing at the Nanoscale/NANO 6 Thursday Sessions
       Session NS+NANO6-ThM

Paper NS+NANO6-ThM6
Ultraflat Nanosphere Lithography

Thursday, October 5, 2000, 10:00 am, Room 302

Session: Nanostructured Materials
Presenter: W. Frey, Duke University
Authors: W. Frey, Duke University
A. Chilkoti, Duke University
Correspondent: Click to Email
Easy fabrication of periodic features on the submicron scale is needed for many applications ranging from surface-enhanced spectroscopy to quantum structures and nanostructured biofunctional surfaces. For example, biosensors require nanopatterns to be stably bonded to the substrate in solvents, as well as capable of subsequent functionalization by self-assembly chemistry. Additionally, for the study of cell surface-interactions, the nanopatterned surface should have minimal height variation in order to decouple physico-chemical and topographical effects on cell behavior. We have therefore designed a new method, ultraflat nanosphere lithography (UNSL), to create periodic nanopatterned surfaces of well-defined size and minimal topography for different materials that are also stably bonded and are capable of self-assembly chemistry. UNSL is based on nanosphere lithography@footnote 1@ and ultraflat template stripping.@footnote 2@ Nanospheres are self-assembled into close packed hexagonal arrays on mica. Material M1 is evaporated through the mask formed by the self-assembled spheres. After the spheres have been lifted off the substrate, evaporation of material M2 embeds the nanopattern in a much thicker matrix. A silicon or glass substrate is glued to the surface for mechanical support. Finally, the mica is stripped off, revealing an ultraflat pattern of nanotriangles of M1 embedded in M2. In order to demonstrate the feasibility of UNSL, we have chosen pairs of materials M1 (Au, Ag) and M2 (Al, SiO) so that each can be independently functionalized by orthogonal self-assembly, and transparent samples as well as insulator-conductor pairs can be created. We have visualized the nanopatterns fabricated by UNSL using AFM, SEM and Auger electron imaging, and demonstrate that the surface roughness is below 1 nm (rms) over areas of several hundred µm@super 2@. @FootnoteText@ @footnote 1@Deckman, et.al.: Appl. Phys. Lett. 41, 377 (1982)@footnote 2@Hegner, et.al.: Surf. Sci. 291, 39 (1993)