Extending a GTD-based image formation technique to EUV lithography

Andrew Khoh, Donis Flagello, Thomas D Milster, Byoung Il Choi, Ganesh S. Samudra, Yihong Wu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


An image formation technique based on the Geometrical Theory of Diffraction was presented last conference. The technique is a scalar technique and is applicable to infinitely thin and perfectly conducting mask. We explore in this paper the extension of the technique to 1D Extreme Ultra-Violet(EUV) Lithography mask, taking into consideration both the material property and the topography of the mask. Vectorial nature of light is incorporated in the treatment. Results obtained are promising and encouraging. Computation time is relatively much shorter and the technique could simulate irradiance profile for any illumination angle. The technique is simple and elegant and lends understanding to image formation. We conclude that the asymmetry-through-focus characteristic usually found in EUV and Phase Mask imaging is an imaging phenomenon. We also conclude that corrections for proximity effect and pattern infidelity will be needed when EUV Lithography is introduced at the 32 nm node, assuming a system NA of 0.25. Lastly, for a partially coherent illumination, it appears necessary to compute the irradiance corresponding to each illumination point individually.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsR.L. Engelstad
Number of pages8
Volume5037 II
Publication statusPublished - 2003
EventEmerging Lithography Technologies VII - Santa Clara, CA, United States
Duration: Feb 25 2003Feb 27 2003


OtherEmerging Lithography Technologies VII
CountryUnited States
CitySanta Clara, CA



  • DER
  • EUV lithography
  • GTD
  • Image formation technique
  • OPC

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Khoh, A., Flagello, D., Milster, T. D., Choi, B. I., Samudra, G. S., & Wu, Y. (2003). Extending a GTD-based image formation technique to EUV lithography. In R. L. Engelstad (Ed.), Proceedings of SPIE - The International Society for Optical Engineering (Vol. 5037 II, pp. 682-689) https://doi.org/10.1117/12.485501