Supercritical metalens at h-line for high-resolution direct laser writing
h线超临界金属用于高分辨率直接激光写入
h線超臨界金属による高分解能直接レーザ書込み
H선 초임계 금속은 고해상도 직접 레이저 쓰기에 사용
Metales supercríticos de línea h para escritura láser directa de alta resolución
Métal supercritique H - line pour écriture laser directe haute résolution
H - проводной сверхкритический металл для прямой лазерной записи с высоким разрешением
Jichao Fu ¹, Mengting Jiang ¹, Zeng Wang ¹, Yi Fan Chen ¹, Yuanda Liu ¹, Qing Yang Steve Wu ¹, Ai Jia Sim ¹, Jiang Wang ¹ ², Mingxi Chen ¹, Ziyu Wang ¹, Jie Deng ¹, Xiao Song Eric Tang ¹, Kun Huang 黄坤 ³, Hong Liu ¹, Jinghua Teng 滕京华 ¹
¹ Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Singapore
² School of Microelectronics, Hefei University of Technology, Hefei 230009, China
中国 合肥 合肥工业大学微电子学院
³ Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
中国 合肥 中国科学技术大学 光学与光学工程系
Supercritical lens (SCL) can break the diffraction limit in the far field and has been demonstrated for high-resolution scanning confocal imaging. Its capability in sharper focusing and needle-like long focal depth should allow high-resolution lithography at violet or ultraviolet (UV) wavelength, however, this has never been experimentally demonstrated.
As a proof of concept, in this paper SCLs operating at 405 nm (h-line) wavelength with smaller full-width-at-half-maximum focal spot and longer depth of focus than conventional Fresnel zone lens while maintaining controlled side lobes are designed for direct laser writing (DLW) lithography. Aluminum nitride (AlN) with a high refractive index and low loss in UV-visible range is used to fabricate nanopillar-based metasurfaces structure for the metalens.
Grating arrays with improved pitch resolution are fabricated using the SCLs with sub-diffraction-limit focusing capability. The AlN-based metasurface for SCLs at short wavelength for DLW could extend further to UV or deep UV lithography and might be of great interest to both the research and industry applications.
