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Journal of the Optical Society of America A

Journal of the Optical Society of America A


  • Vol. 18, Iss. 5 — May. 1, 2001
  • pp: 1093–1100

Numerical feasibility study of the fabrication of subwavelength structure by mask lithography

Hiroyuki Ichikawa and Hisao Kikuta  »View Author Affiliations

JOSA A, Vol. 18, Issue 5, pp. 1093-1100 (2001)

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Electromagnetic diffraction of a light wave by a single aperture of subwavelength width and subsequent propagation in a lossy medium are numerically investigated. This diffraction problem simulates exposure of a resist with an amplitude mask. It is found that there is the possibility of fabricating a λ/2 structure on a resist of λ/4 thickness, where λ is the wavelength of the exposing light in vacuum, by conventional contact or by proximity lithography. It is also found that an air gap between a mask and a resist of up to λ/2 does not have a significant effect on resolution. This approach permits easy and cost-effective fabrication of subwavelength structures and leads to wide availability of diffractive optical elements in the nonscalar domain.

© 2001 Optical Society of America

OCIS Codes
(050.1220) Diffraction and gratings : Apertures
(050.1380) Diffraction and gratings : Binary optics
(050.1970) Diffraction and gratings : Diffractive optics
(220.3740) Optical design and fabrication : Lithography
(220.4000) Optical design and fabrication : Microstructure fabrication

Original Manuscript: July 28, 2000
Revised Manuscript: October 23, 2000
Manuscript Accepted: November 1, 2000
Published: May 1, 2001

Hiroyuki Ichikawa and Hisao Kikuta, "Numerical feasibility study of the fabrication of subwavelength structure by mask lithography," J. Opt. Soc. Am. A 18, 1093-1100 (2001)

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  27. A thick resist is employed for Fig. 6, because the purpose here is to observe a typical intensity gradient, particularly in the xdirection, inside the resist. In fact, there is little difference between intensity profiles for thick (d=500 nm) and thin (d=100 nm) resist layers near the incident plane (x=0 nm).
  28. Strictly speaking, in particular when the intensity distribution contains abrupt changes in the x direction, the field extension for an unpolarized light source should be obtained by use of the sum of the intensities for TE and TM waves at each z position.
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  32. For example, such as explained in J. Hargreaves, “Liquid phase silylation of a bilayer resist system,” Microelectron. Eng. 45, 329–349 (1999). [CrossRef]

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