High-index fluoride materials for 193 nm immersion lithography

Teruhiko Nawata, Yoji Inui, Isao Masada, Eiichi Nishijima, Toshiro Mabuchi, Naoto Mochizuki, Hiroki Satoh, Tsuguo Fukuda

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Citations (Scopus)


BaLiF3 single crystal has been studied as the lens material for the candidate 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 might fulfill the requirement, and intrinsic birefringence is relatively lower than other candidate materials. It is estimated that the cause of scattering in the BaLiF3 crystal is aggregation of excess LiF component. The special annealing process to eliminate excess LiF component was applied to improve the transparency. The internal transparency was improved to more than 97%/cm by optimizing growth conditions and annealing conditions.

Original languageEnglish
Title of host publicationOptical Microlithography XX
EditionPART 2
Publication statusPublished - 2007
EventOptical Microlithography XX - San Jose, CA, United States
Duration: 2007 Feb 272007 Mar 2

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
NumberPART 2
ISSN (Print)0277-786X


ConferenceOptical Microlithography XX
Country/TerritoryUnited States
CitySan Jose, CA


  • BaLiF
  • Czochralski
  • High index
  • Immersion lithography
  • Single crystal


Dive into the research topics of 'High-index fluoride materials for 193 nm immersion lithography'. Together they form a unique fingerprint.

Cite this