Fluorescence alignment simulation for atomic-scale position adjustment in ultraviolet nanoimprint lithography

Hiromasa Niinomi, Subaru Harada, Toshiaki Hayakawa, Masaru Nakagawa

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

The alignment process of ultraviolet (UV) nanoimprint lithography requires a further sophisticated method to detect infinitesimal misalignments between a synthetic quartz mold and a silicon substrate. Previously, we proposed a fluorescence-alignment method based on the analysis of the additive-type moiré fringes generated by the interferences of fluorescence emission from fluorescent UV-curable liquid filling the concave bar-mark arrays on a synthetic quartz mold and a silicon substrate. The proposed method significantly reduces the cost of mold fabrication and simplifies the in-liquid process compared to the conventional method based on multiplicative-type moiré fringes prevailing in the industry. This is because the fluorescence-alignment method is free from the problem of the refractive index matching between mold and UV-curable liquid materials. However, its position accuracy remains as large as sub-10 nm scales in principle. In this study, through simulation using image drawing and analysis software, we demonstrate that a sophisticated fluorescence alignment can realize atomic-scale precision for position accuracy by attempting the following concepts: (i) the application of the principle on position determination of a fluorescent single-molecule to that of an individual bar-mark fluorescence signal; (ii) effective use of high bit-depth of recent imaging devices; and (iii) accumulations of the information on the positions of multiple bar-marks with periodicities by fitting their fluorescence intensity profiles using a periodic function.

Original languageEnglish
Article number062602
JournalJournal of Vacuum Science and Technology B
Volume40
Issue number6
DOIs
Publication statusPublished - 2022 Dec 1

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