A 6.7-nm beyond EUV source as a future lithography source

Takamitsu Otsuka, Bowen Li, Colm O'Gorman, Thomas Cummins, Deirdre Kilbane, Takeshi Higashiguchi, Noboru Yugami, Weihua Jiang, Akira Endo, Padraig Dunne, Gerry O'Sullivan

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

12 Citations (Scopus)


We demonstrate an efficient extreme ultraviolet (EUV) source for operation at λ?= 6.7 nm by optimizing the optical thickness of gadolinium (Gd) plasmas. Using low initial density Gd targets and dual laser pulse irradiation, we observed a maximum EUV conversion efficiency (CE) of 0.54% for 0.6% bandwidth (BW) (1.8% for 2%BW), which is 1.6 times larger than the 0.33% (0.6%BW) CE produced from a solid density target. Enhancement of the EUV CE by use of a low-density plasma is attributed to the reduction of self-absorption effects.

Original languageEnglish
Title of host publicationExtreme Ultraviolet (EUV) Lithography III
Publication statusPublished - 2012
Externally publishedYes
EventExtreme Ultraviolet (EUV) Lithography III - San Jose, CA, United States
Duration: 13 Feb 201216 Feb 2012

Publication series

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


ConferenceExtreme Ultraviolet (EUV) Lithography III
Country/TerritoryUnited States
CitySan Jose, CA


  • Beyond extreme ultraviolet (BEUV)
  • Gd
  • Laser-produced plasmas
  • Rare-earth
  • Tb


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