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Title: Reverse-absorbance-modulation-optical lithography for optical nanopatterning at low light levels

Abstract

Absorbance-Modulation-Optical Lithography (AMOL) has been previously demonstrated to be able to confine light to deep sub-wavelength dimensions and thereby, enable patterning of features beyond the diffraction limit. In AMOL, a thin photochromic layer that converts between two states via light exposure is placed on top of the photoresist layer. The long wavelength photons render the photochromic layer opaque, while the short-wavelength photons render it transparent. By simultaneously illuminating a ring-shaped spot at the long wavelength and a round spot at the short wavelength, the photochromic layer transmits only a highly confined beam at the short wavelength, which then exposes the underlying photoresist. Many photochromic molecules suffer from a giant mismatch in quantum yields for the opposing reactions such that the reaction initiated by the absorption of the short-wavelength photon is orders of magnitude more efficient than that initiated by the absorption of the long-wavelength photon. As a result, large intensities in the ring-shaped spot are required for deep sub-wavelength nanopatterning. In this article, we overcome this problem by using the long-wavelength photons to expose the photoresist, and the short-wavelength photons to confine the “exposing” beam. Thereby, we demonstrate the patterning of features as thin as λ/4.7 (137 nm for λmore » = 647 nm) using extremely low intensities (4-30 W/m{sup 2}, which is 34 times lower than that required in conventional AMOL). We further apply a rigorous model to explain our experiments and discuss the scope of the reverse-AMOL process.« less

Authors:
; ; ;  [1]; ;  [2];  [3]
  1. Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States)
  2. Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
  3. Mulhouse Institute for Material Sciences, CNRS LRC 7228, BP2488, Mulhouse 68200 (France)
Publication Date:
OSTI Identifier:
22611568
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 6; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; BEAMS; DIFFRACTION; LAYERS; MODULATION; MOLECULES; PHOTONS; VISIBLE RADIATION; WAVELENGTHS

Citation Formats

Majumder, Apratim, E-mail: apratim.majumder@utah.edu, Wan, Xiaowen, Masid, Farhana, Menon, Rajesh, Pollock, Benjamin J., Andrew, Trisha L., and Soppera, Olivier. Reverse-absorbance-modulation-optical lithography for optical nanopatterning at low light levels. United States: N. p., 2016. Web. doi:10.1063/1.4954178.
Majumder, Apratim, E-mail: apratim.majumder@utah.edu, Wan, Xiaowen, Masid, Farhana, Menon, Rajesh, Pollock, Benjamin J., Andrew, Trisha L., & Soppera, Olivier. Reverse-absorbance-modulation-optical lithography for optical nanopatterning at low light levels. United States. doi:10.1063/1.4954178.
Majumder, Apratim, E-mail: apratim.majumder@utah.edu, Wan, Xiaowen, Masid, Farhana, Menon, Rajesh, Pollock, Benjamin J., Andrew, Trisha L., and Soppera, Olivier. Wed . "Reverse-absorbance-modulation-optical lithography for optical nanopatterning at low light levels". United States. doi:10.1063/1.4954178.
@article{osti_22611568,
title = {Reverse-absorbance-modulation-optical lithography for optical nanopatterning at low light levels},
author = {Majumder, Apratim, E-mail: apratim.majumder@utah.edu and Wan, Xiaowen and Masid, Farhana and Menon, Rajesh and Pollock, Benjamin J. and Andrew, Trisha L. and Soppera, Olivier},
abstractNote = {Absorbance-Modulation-Optical Lithography (AMOL) has been previously demonstrated to be able to confine light to deep sub-wavelength dimensions and thereby, enable patterning of features beyond the diffraction limit. In AMOL, a thin photochromic layer that converts between two states via light exposure is placed on top of the photoresist layer. The long wavelength photons render the photochromic layer opaque, while the short-wavelength photons render it transparent. By simultaneously illuminating a ring-shaped spot at the long wavelength and a round spot at the short wavelength, the photochromic layer transmits only a highly confined beam at the short wavelength, which then exposes the underlying photoresist. Many photochromic molecules suffer from a giant mismatch in quantum yields for the opposing reactions such that the reaction initiated by the absorption of the short-wavelength photon is orders of magnitude more efficient than that initiated by the absorption of the long-wavelength photon. As a result, large intensities in the ring-shaped spot are required for deep sub-wavelength nanopatterning. In this article, we overcome this problem by using the long-wavelength photons to expose the photoresist, and the short-wavelength photons to confine the “exposing” beam. Thereby, we demonstrate the patterning of features as thin as λ/4.7 (137 nm for λ = 647 nm) using extremely low intensities (4-30 W/m{sup 2}, which is 34 times lower than that required in conventional AMOL). We further apply a rigorous model to explain our experiments and discuss the scope of the reverse-AMOL process.},
doi = {10.1063/1.4954178},
journal = {AIP Advances},
number = 6,
volume = 6,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}