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

Susumu Iida; Ryoichi Hirano; Tsuyoshi Amano; Hidehiro Watanabe

doi:10.1117/1.JMM.13.4.043015

11 December 2014 Impact of B₄C capping layer for extreme ultraviolet mask on the sensitivity of patterned mask inspection using a projection electron microscope

Susumu Iida, Ryoichi Hirano, Tsuyoshi Amano, Hidehiro Watanabe

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Journal of Micro/Nanolithography, MEMS, and MOEMS, Vol. 13, Issue 4, 043015 (December 2014). https://doi.org/10.1117/1.JMM.13.4.043015

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.

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Susumu Iida, Ryoichi Hirano, Tsuyoshi Amano, and Hidehiro Watanabe "Impact of B₄C capping layer for extreme ultraviolet mask on the sensitivity of patterned mask inspection using a projection electron microscope," Journal of Micro/Nanolithography, MEMS, and MOEMS 13(4), 043015 (11 December 2014). https://doi.org/10.1117/1.JMM.13.4.043015

Published: 11 December 2014

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