EUVL mask inspection at Hydrogen Lyman Alpha

Thiago S. Jota, Tom D. Milster

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


Mask inspection is an outstanding challenge for Extreme Ultra-Violet Lithography (EUVL). The purpose of this investigation is to compare imaging characteristics of ArF and KrF inspection sources to imaging characteristics using a source at the Lyman-alpha line of Hydrogen at 121.6nm (HLA). HLA provides a raw resolution improvement of 37% to ArF and 51% to KrF, based on proportional wavelength scaling. The HLA wavelength is in an atmospheric transmission window, so a vacuum environment is not required. Our comparison uses rigorous vector imaging techniques to simulate partially coherent illumination schemes and reasonably accurate mask material properties and dimensions. Contrast is evaluated for representative spatial frequencies. Imaging and detection of defects are also considered with NILS and MEEF. The goal is high throughput inspection with maximum resolution, contrast, and sensitivity.

Original languageEnglish (US)
Title of host publicationPhotomask Technology 2012
EditorsFrank E. Abboud, Thomas B. Faure
ISBN (Electronic)9780819492609
StatePublished - 2012
EventSPIE Conference on Photomask Technology 2012 - Monterey, United States
Duration: Sep 11 2012Sep 13 2012

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSPIE Conference on Photomask Technology 2012
Country/TerritoryUnited States


  • EUV
  • Inspection
  • Lithography
  • Lyman alpha

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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