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Journal of the Optical Society of America A

Journal of the Optical Society of America A


  • Editor: Stephen A. Burns
  • Vol. 23, Iss. 4 — Apr. 1, 2006
  • pp: 821–828

Incorporating mask topography edge diffraction in photolithography simulations

Jaione Tirapu-Azpiroz and Eli Yablonovitch  »View Author Affiliations

JOSA A, Vol. 23, Issue 4, pp. 821-828 (2006)

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In deep ultraviolet lithography simulations, conventional application of Kirchhoff’s boundary conditions on the mask surface provides the so-called “thin-mask” approximation of the object field. Current subwavelength lithographic operation, however, places a serious limitation on this approximation, which fails to account for the topographical, or “thick-mask,” effects. In this paper, a new simulation model is proposed that is theoretically founded on the well-established physical theory of diffraction. This model relies on the key result that diffraction effects can be interpreted as an intrinsic edge property, and modeled with just two fixed parameters: width and transmission coefficient of a locally determined boundary layer applied to each chrome edge. The proposed model accurately accounts for thick-mask effects of the fields on the mask, greatly improving the accuracy of aerial image simulations in photolithography, while maintaining a reasonable computational cost.

© 2006 Optical Society of America

OCIS Codes
(110.3960) Imaging systems : Microlithography
(260.1960) Physical optics : Diffraction theory
(260.2110) Physical optics : Electromagnetic optics

ToC Category:
Imaging Systems

Original Manuscript: April 19, 2005
Revised Manuscript: July 16, 2005
Manuscript Accepted: August 24, 2005

Jaione Tirapu-Azpiroz and Eli Yablonovitch, "Incorporating mask topography edge diffraction in photolithography simulations," J. Opt. Soc. Am. A 23, 821-828 (2006)

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