Share Email Print

Proceedings Paper

Characterization and monitoring of photomask edge effects
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

An experimental technique for quantitatively characterizing edge effect contributions in transmission through thick photomasks is described and evaluated through electromagnetic simulation. The technique consists of comparing the 0th order transmission for various duty cycles to the expected experimental behavior from a thin mask model. The real electric field component from the edges is proportional to the shift in the position of the minimum energy in the 0th order field away from the expected thin mask location. The square root of the minimum 0th order diffraction energy normalized to a clear mask gives the imaginary edge contribution. The results indicate that Alternating Phase Shifting Masks (ALT-PSM) and Attenuating Phase Shifting Masks (ATT-PSM) technologies have significant edge effects on the order of 0.1λ to 0.2λ per edge respectively, as well as polarization dependence. For periods of 2 wavelengths and larger these edge contribution values are nearly independent of pitch. The existence of an imaginary (or quadrature) phase component is shown to result in an additive linear variation of line edge shortening through focus. This tilt can be interpreted as a focus shift of the normal parabolic behavior and is about 0.5 Rayleigh units (RU). This focus shift depends to some extent on the surrounding layout as well as the feature itself.

Paper Details

Date Published: 30 October 2007
PDF: 7 pages
Proc. SPIE 6730, Photomask Technology 2007, 67301U (30 October 2007); doi: 10.1117/12.746805
Show Author Affiliations
Marshal A. Miller, Univ. of California, Berkeley (United States)
Andrew R. Neureuther, Univ. of California, Berkeley (United States)
Daniel P. Ceperley, Univ. of California, Berkeley (United States)
Juliet Rubinstein, Univ. of California, Berkeley (United States)

Published in SPIE Proceedings Vol. 6730:
Photomask Technology 2007
Robert J. Naber; Hiroichi Kawahira, Editor(s)

© SPIE. Terms of Use
Back to Top