1 April 2006 Progress in the fabrication of low-defect density mask blanks for extreme ultraviolet lithography
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J. of Micro/Nanolithography, MEMS, and MOEMS, 5(2), 023003 (2006). doi:10.1117/1.2198853
Extreme ultraviolet lithography (EUVL) is the leading next-generation lithography (NGL) technology to succeed optical lithography at the 32-nm node and beyond. The technology uses a multilayer-based reflective optical system, and the development of suitable, defect-free mask blanks is the greatest challenge facing the commercialization of EUVL. We describe recent progress toward the development of a commercial tool and process for the production of EUVL mask blanks. Using the resources at Mask Blank Development Center at SEMATECH-North in Albany, New York, we are able to decrease the mean multilayer-coating-added defect density on 6-in. square quartz substrates by almost an order of magnitude, from ~0.5 defects/cm2 to ~0.055 defects/cm2 for particles ≥80 nm in size (polystyrene latex equivalent). We also obtain a "champion" mask blank with an added defect density of only ~0.005 defects/cm2. This advance is due primarily to a compositional analysis of the particles using focused ion beam and energy dispersive analysis of x-rays (EDX) followed by tool and procedural upgrades based on best engineering practices and judgment. Another important specification for masks blanks is the coating uniformity, and we have simultaneously achieved a centroid wavelength uniformity of 0.4% and a coating-added defect density of 0.06 def/cm2.
Rajul V. Randive, Andy Ma, Patrick A. Kearney, David Krick, Ira Reiss, Paul B. Mirkarimi, Eberhard Adolf Spiller, "Progress in the fabrication of low-defect density mask blanks for extreme ultraviolet lithography," Journal of Micro/Nanolithography, MEMS, and MOEMS 5(2), 023003 (1 April 2006). http://dx.doi.org/10.1117/1.2198853


Extreme ultraviolet lithography






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