Maskless photolithography based on the digital micromirror device (DMD), a two-dimensional micromirror array, is considered the next-generation low-cost lithographic technology. However, the DMD-based digital photolithography has been implemented only for micrometre-scale pattern generation, whereas sophisticated photonic devices require the feature sizes of approximately 100 nm. In this study, a high-magnification objective lens (200×) is adopted for a custom-built digital photolithography system to generate submicron-scale patterns. Techniques augmenting the digital photolithography, pattern tilting and greyscale exposure, are also improvised. Photonic crystal band-edge lasers of various lattice structures and periods are demonstrated as quality-assessment testbeds.
Authors: Minsu Kang, Changhyun Han, and Heonsu Jeon* (Seoul National University)
Journal: Optica 7 (12) 1788-1795 (2020)
Publication date: 20 December 2020
Link: http://doi.org/10.1364/OPTICA.406304
