Interference lithography by a soft x-ray laser beam: Nanopatterning on photoresists

Abstract

We have studied the feasibility of high-resolution laser interference lithography using a tabletop 46.9 nm, 1.5 ns Ar laser, combined with two different optical configurations based on a Lloyd's mirror interferometer. Using one of these schemes we have encoded periodic grating structures with a half pitch of 42 nm and a vertical modulation of 5 nm on a commercial PMMA photoresist. Experiments performed with larger half-pitch structures and detailed theoretical calculations demonstrate the potentiality of producing periodic structures with a half-pitch resolution down to 20 nm and a height of up to 60 nm. The results can be of considerable interest for the development of a complete high-resolution lithographic process operating with the 47 nm laser wavelength. © 2007 American Institute of Physics.