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Proceedings Paper

Evaluation of aperture mask degradation in electron-beam lithography using line edge roughness of resist patterns
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Paper Abstract

Line edge roughness (LER) of resist patterns in electron beam (EB) lithography was measured to evaluate aperture mask degradation. LER was quantified using a scanning electron microscope (SEM) and the influence of SEM resolution on measured LER value was investigated. Degrading the SEM resolution reduced the measured LER value of an identical line pattern because smaller ripple at pattern edge cannot be detected from inferior SEM image. Cross-sectional SEM observation revealed that 90-days EB irradiation deposited carbon-based contamination on the mask surface, which increased LER from 4.7 nm to 6.4 nm and aggravated the resolution limit from 74 nm to 81 nm. The increase ratio in LER of the left edge of a line pattern was larger than that of the right edge, indicating that the degradation of bottom aperture located at the lower part of an EB direct writer was severer. 95-days EB exposure caused no degradation of the aperture mask. It was concluded that the electrification of the contamination affecting aerial-image quality increased LER.

Paper Details

Date Published: 5 September 2001
PDF: 8 pages
Proc. SPIE 4409, Photomask and Next-Generation Lithography Mask Technology VIII, (5 September 2001); doi: 10.1117/12.438366
Show Author Affiliations
Masaki Yoshizawa, Sony Corp. (Japan)
Shigeru Moriya, Sony Corp. (Japan)

Published in SPIE Proceedings Vol. 4409:
Photomask and Next-Generation Lithography Mask Technology VIII
Hiroichi Kawahira, Editor(s)

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