2 February 2016 Viability of pattern shift for defect-free extreme ultraviolet lithography photomasks
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J. of Micro/Nanolithography, MEMS, and MOEMS, 15(2), 021005 (2016). doi:10.1117/1.JMM.15.2.021005
Several challenges hinder extreme ultraviolet lithography (EUVL) photomask fabrication and its readiness for high-volume manufacturing (HVM). The lack in availability of pristine defect-free blanks as well as the absence of a robust mask repair technique mandates defect mitigation through pattern shift for the production of defect-free photomasks. By using known defect locations on a blank, the mask design can be intentionally shifted to avoid patterning directly over a defect. The work presented here provides a comprehensive look at pattern shift implementation to intersect EUV HVM for the 7-nm technology node (N7). An empirical error budget to compensate for various measurement errors, based on the latest HVM inspection and write tool capabilities, is first established and then verified postpatterning. The validated error budget is applied to 20 representative EUV blanks and pattern shift is performed using fully functional N7 chip designs that were recently used to fabricate working silicon–germanium devices. Probability of defect-free masks are explored for various N7 photomask levels, including metal, contact, and gate cut layers. From these results, an assessment is made on the current viability of defect-free EUV masks and what is required to construct a complete defect-free EUV mask set.
© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
Zhengqing John Qi, Jed Rankin, Eisuke Narita, Masayuki Kagawa, "Viability of pattern shift for defect-free extreme ultraviolet lithography photomasks," Journal of Micro/Nanolithography, MEMS, and MOEMS 15(2), 021005 (2 February 2016). https://doi.org/10.1117/1.JMM.15.2.021005

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