Understanding the ion beam in EUV mask blank production

Patrick Kearney, Vibhu Jindal, Alfred Weaver, Pat Teora, John Sporre, David N Ruzic, Frank Goodwin

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


One of the major technical hurdles to be overcome before EUV lithography can enter high volume manufacturing is the amount of defects in EUV mask blanks, many of which occur during the EUV reflector deposition process. The technology currently used to deposit this reflector is ion beam sputter deposition. Understanding the properties of the ion beam and the nature of the plasma in the deposition chamber is therefore critical to understanding defect production mechanisms and subsequently eliminating them. In this work, we have studied how the source parameters influence ion beam divergence, its footprint on the target, and the amount of beam that misses the target and hits the shielding. By optimizing the source parameters, we can modulate certain target- and shield-specific defect types. We have compared our data with models of source performance and found general agreement, enabling the theory to be fine-tuned based on the results of the measurements. Models are being developed to better describe actual source performance. We have also investigated the plasma conditions the ion beam creates in the tool, which is crucial to understanding the transport of defects from their source to the mask. A well characterized ion beam and plasma will lead to process and tool changes that will ultimately reduce defect levels in EUV mask blanks.

Original languageEnglish (US)
Title of host publicationExtreme Ultraviolet (EUV) Lithography III
StatePublished - 2012
EventExtreme Ultraviolet (EUV) Lithography III - San Jose, CA, United States
Duration: Feb 13 2012Feb 16 2012


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


  • Defects
  • EUVL
  • Ion beam sputtering
  • Mask blank deposition

ASJC Scopus subject areas

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


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