Fluoride single crystals for the next generation lithography

Teruhiko Nawata, Yoji Inui, Toshiro Mabuchi, Naoto Mochizuki, Isao Masada, Eiichi Nishijinia, Hiroki Sato, Tsuguo Fukuda

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

4 Citations (Scopus)


BaLiF3 single crystal has been studied as the candidate for the last lens material of the next generation high index immersion lithography system. Although the refractive index of BaLiF3 is 1.64 at 193nm which is not sufficient for the requirement, other optical properties such as 193nm transparency and laser durability fulfill the requirement. It is estimated that the cause of both high SBR part and inhomogeneity of refractive index of BaLiF3 seems to present along the faces of slip planes which are observed by crossed Nicol observation. As a result of comparative study of various direction perpendiculars to the growth axis, good crystallinity with less slip planes has been obtained by shifting the growth axis from 〈100〉 which is adequate for the last lens production. MgF2 single crystal studied as the polarizer material for high power ArF laser oscillator, and crystal with excellent laser durability and large diameter (> 100mm) has been developed by CZ technique. In addition crystals oriented along both c-axis and a-axis were successfully grown.

Original languageEnglish
Title of host publicationOptical Microlithography XXI
Publication statusPublished - 2008 Jun 25
EventOptical Microlithography XXI - San Jose, CA, United States
Duration: 2008 Feb 262008 Feb 29

Publication series

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


ConferenceOptical Microlithography XXI
Country/TerritoryUnited States
CitySan Jose, CA


  • BaLiF
  • Czochralski
  • High index
  • Last lens
  • MgF
  • Single crystal

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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