Paper
1 July 2002 EUVL masks: requirements and potential solutions
Author Affiliations +
Abstract
Significant progress has been made in developing mask fabrication processes for extreme ultraviolet lithography (EUVL). The mask blank for EUVL consists of a low thermal expansion material substrate having a square photomask form factor that is coated with Mo/Si multilayers. A SEMI standard is now available for mask substrates. SEMI standards are also being developed for mask mounting, for mask blank multilayers and absorbers and for mask handling and storage. Several commercial suppliers are developing polishing processes for LTEM substrates, and they are progressing toward meeting the requirements for flatness, surface roughness, and defects. Significant progress has been made in developing mask blank multilayer coating processes with low added defect density. Besides lowering added defect density, methods to reduce defect printability are being developed to effectively enable repair of many defect types. Calculations of EUVL mask cost indicate that defect repair processes could increase yield of EUV mask blanks and allow initial defect density targets for mask blanks to be relaxed. The mask patterning process for EUVL is nearly the same as that for conventional binary optical lithography masks. Eight absorbers have been evaluated, and two absorbers-TaN and Cr--will probably meet the requirements after some further development.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Scott Daniel Hector "EUVL masks: requirements and potential solutions", Proc. SPIE 4688, Emerging Lithographic Technologies VI, (1 July 2002); https://doi.org/10.1117/12.472284
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Cited by 31 scholarly publications.
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KEYWORDS
Photomasks

Multilayers

Extreme ultraviolet lithography

Coating

Inspection

Reflectivity

Extreme ultraviolet

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