Highly Uniform Plasmonic Interference Lithography Assisted by Hyperbolic Multilayer Graphene
- PDF / 1,989,832 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 62 Downloads / 259 Views
Highly Uniform Plasmonic Interference Lithography Assisted by Hyperbolic Multilayer Graphene Yongyue Qian 1 & Biao Li 1 & Lei Min 1 & Weiguang Liu 1 & Juan Liu 1 & Bin Hu 1 Received: 5 July 2019 / Accepted: 3 November 2019 # Springer Science+Business Media, LLC, part of Springer Nature 2019
Abstract Plasmonic interference lithography (PIL) is able to break the diffraction limit, realizing deep-subwavelength resolution in a large area. However, because the energy of surface plasmon polariton (SPP) wave is mainly confined on the surface of the metallic layer, the interference patterns in the photoresist layer often suffer from shallowness and nonuniformity. In this work, a PIL structure with highly uniform patterns is proposed, working in the wavelength of 193 nm. The structure consists of a silicon substrate and a photoresist sandwiched by two multilayer graphene films. Due to the hyperbolic property of the multilayer graphene, a slot SPP mode which is weakly dependent on the photoresist thickness is stimulated through volume plasmon polaritons in the hyperbolic multilayer graphene. A uniform periodic pattern with a half-pitch resolution of 29 nm (λ/6.7) maintains even the photoresist thickness that is larger than 80 nm. Our findings may provide a new method to realize robust PIL patterns. Keywords Lithography . Plasmonics . Graphene . Hyperbolic material
Introduction Photolithography, which is a process removing specific patterns from wafer surfaces, is now widely used in the fields of semiconductor and microelectronic industries. However, due to the diffraction limit, which means a light beam is hardly focused in a space with a lateral size smaller than half of the wavelength [1, 2], conventional photolithography techniques have not been able to meet the requirements of integrated device fabrication with ultra-high density. Essentially, the diffraction limit comes from the fact that the subwavelength information is carried only by the evanescent waves existing in the near field [3]. Therefore, one way to push the resolution of photolithography to deep subwavelength scale is utilizing the evanescent waves. Surface plasmon polaritons (SPPs) are evanescent waves that confined on the interface of a metal and a dielectric. Because the wavelength of a SPP wave is smaller than that of the wave in free space and can be engineered by the structure, plasmonic lithography based on the interference
* Bin Hu [email protected] 1
School of Optics and Photonics, Beijing Engineering Research Center for Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081, China
of SPPs has demonstrated its great application potentials in fabricating periodic nanostructures recently [4–17]. The PIL system was originally composed of a photoresist (PR) layer and a metallic grating mask [4, 5] or a prism [6, 7] to stimulate SPP waves. The feature size was in the order of ~λ/4. Then the resolution was improved by a metallic film as a superlens [8] or a reflector [9, 10]. In order to further enhance the resolution, hyp
Data Loading...
