11 March 2002 Multilayer coating requirements for extreme ultraviolet lithography masks
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To meet critical dimension control error budgets for extreme UV lithography (EUVL) tools, the reflectivity bandpass of multilayers on the mask must be well matched to the bandpass of the optical system in the exposure tool. The reflectivity bandpass and peak reflectivity of the mask multilayers must also be highly uniform to minimize illumination uniformity errors in the exposure tool Calculations were performed to determine the required mask multilayer matching to exposure tool optics. Calculated ideal reflectivity curves and measured reflectivity versus wavelength values for typical masks made with ion beam sputtering and for the coating on the optics for the ETS were used. The impact on the mask coating requirements when using more than 6 multilayer- coated optics in production exposure tools was also quantified. To meet error budgets established for the ETS, the mask multilayer coating centroid wavelength at all points in the image field should be 13.334 +/- 0.040 nm, and peak reflectivity must be uniform to within +/- 0.5 percent absolute. A roadmap is proposed for mask multilayer reflectivity requirements for future industry roadmap nodes.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Scott Daniel Hector, Scott Daniel Hector, Eric M. Gullikson, Eric M. Gullikson, Paul B. Mirkarimi, Paul B. Mirkarimi, Eberhard Adolf Spiller, Eberhard Adolf Spiller, Patrick A. Kearney, Patrick A. Kearney, James A. Folta, James A. Folta, "Multilayer coating requirements for extreme ultraviolet lithography masks", Proc. SPIE 4562, 21st Annual BACUS Symposium on Photomask Technology, (11 March 2002); doi: 10.1117/12.458369; https://doi.org/10.1117/12.458369


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