Nanopatterning with interferometric lithography using a compact /spl lambda/=46.9-nm laser

Abstract

We report the imprinting of nanometer-scale gratings by interferometric lithography at = 46 9 nm using an Ne-like Ar capillary discharge laser. Gratings with periods as small as 55 nm were imprinted on poly-methyl methacrylate using a Lloyd's mirror interferometer. This first demonstration of nanopatterning using an extreme ultraviolet (EUV) laser illustrates the potential of compact EUV lasers in nanotechnology applications.Index Terms-Nanotechnology, photolithography, X-ray lasers, X-ray lithography.T HE increasing activity in nanotechnology and nanoscience fuels the need to realize fabrics of periodic structures in the nanometer range. Along this path, table-top extreme ultraviolet (EUV) sources offer exciting new opportunities to demonstrate novel fabrication tools capable of reaching nanometer resolution in small laboratory environments. High repetition rate table-top EUV lasers provide a useful way to record nanoscale features, particularly when the pattern can be created by interference effects that take advantage of the coherence of this type of compact EUV sources. Such maskless scheme, known as interferometric lithography (IL), is capable of producing regular patterns of lines or dots with features approaching over large areas [1]- [6].IL has been previously demonstrated with ultraviolet (UV) and vacuum-ultraviolet (VUV) laser light illumination at 157 nm [7], 193 nm [6], and 257 nm [8], and with 13-nm synchrotron radiation [2], [3]. With VUV lasers, sub-100-nm gratings and grids have been printed using different optical Manuscript

Nanopatterning in a compact setup using table top extreme ultraviolet lasers

“…Another factor that can reduce the intensity in the reflected beam is scattering at the mirror's surface. Detailed analysis of these factors in a former experiment indicated that the loss in contrast due to polarization and angle dependence is only important at incidence angles è > 7°that corresponds to patterns period below 200 nm [26]. Also at these larger incidence angles the scattering in the reflecting surface degrades the reflectivity of the beam and the interference contrast.…”

Multi-Beam Interference Advances and Applications: Nano-Electronics, Photonic Crystals, Metamaterials, Subwavelength Structures, Optical Trapping, and Biomedical Structures

“…Two decades later, multiple MBIL exposures were proposed to generate more complex 2D patterns in a photoresist [138]. Since then, a wide range of structures have been recorded via MBIL using near-infrared [129,[139][140][141][142], visible light [18,31,32,62,88,[143][144][145][146][147][148][149][150][151][152][153], ultraviolet (UV) [62,77,78,99,115,[154][155][156][157][158][159][160], deep-UV [92,101,142,[161][162][163], and extreme-UV sources [164][165][166][167].…”

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.…”

“…These newly developed laser sources open new possibilities to realize efficient nanopatterning in compact (table top size) setups with similar capabilities to systems now only accessible with synchrotron sources [46][47][48]. The development of EUV and soft X-ray lasers that can easily fit on an optical table facilitated the demonstration of a large number of applications including photolithography, interferometry, microscopy, holography, nano-machining, high resolution mass spectroscopy and nano-ablation [49][50][51][52][53][54][55][56][57][58][59][60][61].…”