Methods for fabricating arrays of holes using interference lithography

Optical interference lithography provides a robust patterning technology capable of achieving deep submicron resolution over extremely large field sizes (similar to 1 m(2)). Here, we compare two approaches for fabricating arrays of holes using interferometric techniques. We first show that, by applying an image reversal process to standard two-beam interference lithography, arrays of high aspect ratio holes (2:1) can be generated. This process scales well to submicron periods and allows holes as small as 0.1 mu m to be patterned. Next, we present an analysis of the multiple-beam approach for patterning holes. This technique offers a potentially higher throughput process compared to other techniques. We demonstrate that, while the formation of higher contrast intensity profiles is possible by interfering four or more beams, the shape and modulation depth of such profiles are sensitive to relative phase variations. This dependence complicates the application of multiple-beam techniques for patterning large uniform arrays of resist structures. (C) 1997 American Vacuum Society.