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Journal of Micro/Nanolithography, MEMS, and MOEMS

Toward defect-free fabrication of extreme ultraviolet photomasks
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Paper Abstract

Defect-free fabrication of extreme ultraviolet (EUV) masks relies on the appropriate detection of native defects and subsequent strategies for their elimination. Commercial unavailability of actinic mask-blank inspection systems motivates the identification of an optical inspection methodology most suitable for finding relevant EUV blank defects. Studies showed that 193-nm wavelength inspection found the greatest number of printable defects as compared with rival higher-wavelength systems, establishing deep ultraviolet inspections as the blank defectivity baseline for subsequent mitigation strategies. Next, defect avoidance via pattern shifting was explored using representative 7-nm node metal/contact layer designs and 193-nm mask-blank inspection results. It was found that a significant percentage of native defects could be avoided only when the design was limited to active patterns (i.e., layouts without dummy fill). Total pattern-defect overlap remained ≤5 when metal layer blanks were chosen from the top 35% least defective substrates, while the majority of blanks remained suitable for contacts layers due to a lower active pattern density. Finally, nanomachining was used to address remaining native/multilayer defects. Native catastrophic defects were shown to recover 40% to 70% of target critical dimension after nanomachining, demonstrating the enormous potential for compensating multilayer defects.

Paper Details

Date Published: 12 April 2016
PDF: 7 pages
J. Micro/Nanolith. MEMS MOEMS 15(2) 023502 doi: 10.1117/1.JMM.15.2.023502
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 15, Issue 2
Show Author Affiliations
Zhengqing John Qi, GLOBALFOUNDRIES Inc. (United States)
Jed H. Rankin, GLOBALFOUNDRIES Inc. (United States)
Mark Lawliss, GLOBALFOUNDRIES Inc. (United States)
Karen D. Badger, GLOBALFOUNDRIES Inc. (United States)
Christina Turley, GLOBALFOUNDRIES Inc. (United States)

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