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Journal of Micro/Nanolithography, MEMS, and MOEMS • Open Access

Impact of B4C capping layer for extreme ultraviolet mask on the sensitivity of patterned mask inspection using a projection electron microscope

Paper Abstract

The inspection sensitivity of a patterned extreme ultraviolet mask with B4C-capped multilayer (ML) was investigated using a simulated projection electron microscope (PEM) image. Extrusion and intrusion defects with 16-nm size were detected with their intensity of >10 times the standard deviation of the background level on a half-pitch 64-nm line-and-space pattern. The defect detection sensitivity in this case was higher than that of a Ru-capped ML sample and has a potential to meet the requirement for beyond 16-nm node generation from the standpoint of patterned mask inspection using the PEM technique. These results indicate that the B4C capping layer, besides its good durability, has an advantage for high sensitivity of patterned mask inspection. The optimal condition of the incident beam energy was found to be 500 and 1,000 eV for the samples of B4C-capped ML and B4C-buffered Ru-capped ML, respectively. The sensitivity of defect detection was strongly affected by the difference of secondary electron emission coefficients (SEECs) between the absorber layer and capping layer. However, the small incident beam energy was found to be preferable when the SEEC difference was relatively high.

Paper Details

Date Published: 11 December 2014
PDF: 7 pages
J. Micro/Nanolith. 13(4) 043015 doi: 10.1117/1.JMM.13.4.043015
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 13, Issue 4
Show Author Affiliations
Susumu Iida, EUVL Infrastructure Development Ctr., Inc. (Japan)
Ryoichi Hirano, EUVL Infrastructure Development Ctr., Inc. (Japan)
Tsuyoshi Amano, EUVL Infrastructure Development Ctr., Inc. (Japan)
Hidehiro Watanabe, EUVL Infrastructure Development Ctr., Inc. (Japan)


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