Fabrication of Masters for Extreme Precision NanoImprinting of Optical Gratings

University Of Louisville Research Foundation Inc, Louisville KY

Investigators

Abstract

Thin film deposition processes are capable of nanometer and even atomically precise fabrication of layered structures. While the capabilities of deposition are well developed to the point of routine use by the optics and semiconductor devices manufacturers, application of deposition methods to extreme precision patterning and lithographic fabrication has received, at best, limited consideration. This degree of precision is especially needed in the fabrication of sub-wavelength diffractive optics. This study is aimed at a preliminary evaluation of the potential of multilayer stacks to be fabricated and processed into three dimensional master stampers for molding or casting high aspect ratio, nanoscale features in polymers. The vertical dimension of the pattern is produced by cleaving the material, polishing the cleaved surface as required, and chemically etching back selected layers of one material type to produce a bi-level topography. Not only can stamps for one-dimensional bragg-type gratings be produced by deposition, but curved stamps (used to mold sub-wavelength lenses) can be produced by deposition onto curved surfaces (e.g. optical fibers or anisotrpically etched silicon.) Layers of from 5 to 200 nanometers will be deposited using and extending our recent electroplating methods that are noted for increased mechanical strength, reduced grain size and the potential for producing films on the order of one nanometer roughness. One of the most significant outcomes of this study would be the successful demonstration of electrodeposition to fabricate precisely controlled layers as an alternative to the more traditional, but much more expensive, physical deposition methods of sputtering and evaporation.