METHODS FOR FABRICATING ARRAYS OF HOLES USING INTERFERENCE LITHOGRAPHY

Optical interference lithography provides a robust patterning technolo gy 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 allow s holes as small as 0.1 mu m to be patterned. Next, we present an anal ysis of the multiple-beam approach for patterning holes. This techniqu e offers a potentially higher throughput process compared to other tec hniques. We demonstrate that, while the formation of higher contrast i ntensity profiles is possible by interfering four or more beams, the s hape and modulation depth of such profiles are sensitive to relative p hase variations. This dependence complicates the application of multip le-beam techniques for patterning large uniform arrays of resist struc tures. (C) 1997 American Vacuum Society.