Abstract
The rapid development of nanotechnologies and sciences has led to the great demand for novel lithography methods allowing large area, low cost and high resolution nano fabrications. Characterized by unique sub-diffraction optical features like propagation with an ultra-short wavelength and great field enhancement in subwavelength regions, surface plasmon polaritons (SPPs), including surface plasmon waves, bulk plasmon polaritons (BPPs) and localized surface plasmons (LSPs), have become potentially promising candidates for nano lithography. In this paper, investigations into plasmonic lithography in the manner of point-to-point writing, interference and imaging were reviewed in detail. Theoretical simulations and experiments have demonstrated plasmonic lithography resolution far beyond the conventional diffraction limit, even with ultraviolet light sources and single exposure performances. Half-pitch resolution as high as 22 nm (~1/17 light wavelength) was observed in plasmonic lens imaging lithography. Moreover, not only the overview of state-of-the-art results, but also the physics behind them and future research suggestions are discussed as well.
Highlights
Since its invention in about 1960, optical lithography has made a large contribution to the present integrated circuits industry, and has been widely employed in investigations spanning electronics, micro optics, photonics, medical and biology, new materials, etc
Light sources with a shorter wavelength are employed in advanced optical lithography, including deep ultraviolet (DUV) of 248 and 193 nm, and even extreme ultraviolet (EUV) of about 13.5 nm [1]
For alternate metal/dielectric multilayer coupling the bulk plasmon polaritons (BPPs) mode, the transmitted light is effectively restricted in specific kx wave vector window of hyperbolic metamaterial, outside of which the light transmission drops to zero
Summary
Since its invention in about 1960, optical lithography has made a large contribution to the present integrated circuits industry, and has been widely employed in investigations spanning electronics, micro optics, photonics, medical and biology, new materials, etc. It is worth notifying that the short exposure depth issue in conventional near-field lithography could be considerably relived in this case, with the help of evanescent waves amplification and resolution-enhanced technologies by engineering the wave front of SPPs in the imaging process [25] This point is very important from the viewpoint of practical applications, as separating the operational manner could be supported in plasmonic imaging lens lithography. Nano patterns could be fabricated by only employing low-cost, long-wavelength light sources like mercury lamps and He-Cd lasers, etc., fully commercialized and developed materials of resists and no complex optics, just simple illumination of plasmonic lithography structures. The remaining problems and outlooks of further investigations of plasmonic lithography will be given in the end
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