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 46.9nm, 1.5ns 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 42nm and a vertical modulation of 5nm 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 20nm and a height of up to 60nm. The results can be of considerable interest for the development of a complete high-resolution lithographic process operating with the 47nm laser wavelength.

Extreme ultraviolet lithography with table top lasers

“…Table top EUV lasers in combination with a Lloyd's interferometer were also used to print lines and two dimensional arrays of holes and pillars in different photoresists [51,[80][81][82]. Both beams converge at the edge of the mirror on the sample to give rise to a sinusoidal intensity pattern of period d, defined by the wavelength of the light l and the incidence angle y according to Eq.…”

Fabrication of aperiodic subwavelength nanostructures by Grayscale Interference Lithography (GIL)

“…IL is based on interference between two or more coherent laser beams in a Lloyd's mirror interferometer [6] and Mach-Zehnder interferometer [7]. Because of the nature of interference, periodicity is guaranteed if the beam wavefront quality and uniformity are sufficiently good over the required surface area of overlap.…”

Extreme ultraviolet interference lithography at the Paul Scherrer Institut

“…After early interference lithography experiments performed in the vacuum UV 1 and EUV regions, 2 dedicated EUV-IL tools have been set up using synchrotron 3,4 and laser sources. 5 Such tools using plasmabased EUV sources are also being considered. 6 In most reported EUV-IL work, the wavelength of choice has been 13.4 nm.…”