A novel PMMA/NEB bilayer process for sub-20nm gold nanoslits by a selective electron beam lithography and dry etch

A novel electron beam lithography process using PMMA/NEB bilayer was successfully developed for the generation of ultrafine slits as well as broad trenches in a thick gold film. Slit-widths from micrometers down to sub-20nm as the minimum feature size have been achieved. Electron beam lithography on the bilayer of PMMA/NEB with opposite tones between the top and the bottom layer was carefully studied by the contrast curve method. The processing parameters in both electron beam lithography and dry-etch were optimized for achieving ultrafine PMMA/NEB lines as the templates for forming nanoslits in Au films by the subsequent metallization and lift-off. The developed process is not only capable of replicating nano-trenches in Au film, but also applicable for manufacturing concave nanostructures in metals as a whole. Display Omitted A PMMA/NEB bilayer process is studied for nanoslits with the widths range from 100nm to 12nm in 100nm gold film.The width of the gold nanoslits is determined by the thickness of PMMA and the line width of NEB.Advantages of PMMA/NEB bilayer process over single layer process are discussed.