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Proceedings Paper

Aberration analysis using reconstructed aerial images of isolated contacts on attenuated phase-shift masks
Author(s): Franz X. Zach; Chieh-yu Lin; Joseph P. Kirk
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Paper Abstract

A technique for the evaluation of scanner lens aberration is described and analyzed. The method is based on the reconstruction of aerial image distribution using a double exposure technique: A first exposure of the mask feature of interest is followed by uniform background exposure. The topdown images in resist at increasing background exposure dose are analyzed using suitable threshold algorithms to obtain a set of aerial image intensity contour lines. This technique has been applied to the analysis of aerial images formed by isolated contacts using an attenuated PSM. Of particular interest in this case is the aerial image intensity present on the first sidelobe and its angular dependence. In the absence of lens aberrations the sidelobe intensity has no angular dependence whereas the presence of aberrations in the lens generally results in a non-uniform angular sidelobe intensity distributions. A detailed theoretical analysis of the capabilities of this method is being presented: Linearity, zero response and expected results in the presence of various Zernike terms have been studied. We were not only able to separate Zernike terms based on their angular dependence but we also propose a method to assess the order of the radial component.

Paper Details

Date Published: 14 September 2001
PDF: 7 pages
Proc. SPIE 4346, Optical Microlithography XIV, (14 September 2001); doi: 10.1117/12.435674
Show Author Affiliations
Franz X. Zach, IBM Microelectronics Div. (United States)
Chieh-yu Lin, Infineon Technologies Corp. (United States)
Joseph P. Kirk, IBM Microelectronics Div. (United States)

Published in SPIE Proceedings Vol. 4346:
Optical Microlithography XIV
Christopher J. Progler, Editor(s)

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