Paper
17 October 2008 Benchmarking EUV mask inspection beyond 0.25 NA
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Abstract
The SEMATECH Berkeley Actinic Inspection Tool (AIT) is an EUV zoneplate microscope dedicated to photomask research. Recent upgrades have given the AIT imaging system selectable numerical aperture values of 0.25, 0.30, and 0.35 (4 equivalent). The highest of which provides resolution beyond the current generation of EUV lithography research tools, giving above 75% contrast for dense-line features with 100-nm half-pitch on the mask, and above 70% for 88-nm half-pitch. To improve the imaging system alignment, we used through-focus images of small contacts to extract aberration magnitudes and compare with modeling. The astigmatism magnitude reached a low value of 0.08 waves RMS. We present the results of performance benchmarking and repeatability tests including contrast, and line width measurements.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kenneth A. Goldberg, Iacopo Mochi, Patrick P. Naulleau, Hakseung Han, and Sungmin Huh "Benchmarking EUV mask inspection beyond 0.25 NA", Proc. SPIE 7122, Photomask Technology 2008, 71222E (17 October 2008); https://doi.org/10.1117/12.801529
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Cited by 15 scholarly publications.
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KEYWORDS
Photomasks

Extreme ultraviolet

Monochromatic aberrations

Inspection

Imaging systems

Contrast transfer function

Extreme ultraviolet lithography

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