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Proceedings Paper

Improvement of total quality on EUV mask blanks toward volume production
Author(s): Tsutomu Shoki; Masaru Mitsui; Minoru Sakamoto; Noriyuki Sakaya; Masato Ootsuka; Tasuto Asakawa; Takeyuki Yamada; Hideaki Mitsui
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Paper Abstract

Total quality on EUV mask blanks have to be improved toward future volume production. In this paper, progress in EUV blank development and improvement in flatness, bow and ML blank defects as critical issues on EUV blanks were reported. Steadily progress in flatness improvement was made in the past five years by improving polishing processes. A LTE substrate with a high flatness of 78 nm PV in 142 mm square area was achieved in average. Annealing process was developed to make small bow of less than 600 nm after ML coating. It was confirmed that annealed ML blank has stable performance in bow and centroid wavelength values through mask making process. Small bow of less than 300 nm was successfully demonstrated using annealing process and a CrN back side film with high compressive stress. Low defects of 0.05 defects/cm2 at 70 nm SiO2 sensitivity inspected by a Lasertec M1350 was demonstrated on a multilayer (ML) blank with a LTE substrate as best. Small defects over 50 nm in a M7360 were effectively reduced by improvement of polishing process consisting of local polish, touch polish and cleaning.

Paper Details

Date Published: 20 March 2010
PDF: 8 pages
Proc. SPIE 7636, Extreme Ultraviolet (EUV) Lithography, 76360U (20 March 2010); doi: 10.1117/12.849363
Show Author Affiliations
Tsutomu Shoki, HOYA Corp. (Japan)
Masaru Mitsui, HOYA Corp. (Japan)
Minoru Sakamoto, HOYA Corp. (Japan)
Noriyuki Sakaya, HOYA Corp. (Japan)
Masato Ootsuka, HOYA Corp. (Japan)
Tasuto Asakawa, HOYA Corp. (Japan)
Takeyuki Yamada, HOYA Corp. (Japan)
Hideaki Mitsui, HOYA Corp. (Japan)

Published in SPIE Proceedings Vol. 7636:
Extreme Ultraviolet (EUV) Lithography
Bruno M. La Fontaine, Editor(s)

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