Triangular Profile Imprint Molds in Nanograting Fabrication

We have developed a technique based on nanoimprint lithography for the fabrication of nanogratings with controllable line widths and smooth edges. A wet chemical etching process is employed during mold preparation to achieve smooth line edges and a triangle-shaped grating profile. Oblique angle coating (shadow evaporation) of the imprinted resist pattern determines the grating line width. Grating duty cycles can be easily tuned from 30% to 70% of the grating period by simply changing the angle of incidence for shadow evaporation. This technique also enables us to fabricate gratings with highly smooth edges that are not easily achievable by other fabrication methods.