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Proceedings Paper

A 3D numerical study of pinhole diffraction in visible-light point diffraction interferometry
Author(s): Tingwen Xing; Jiajun Xu; Fuchao Xu
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Paper Abstract

The projection objectives,used in modern projection lithography, such as deep-ultraviolet lithography (DUVL), or extreme-ultraviolet lithography (EUVL), desire very high-quality optics. It has placed stringent requirements on the accuracy of the interferometers used for optical metrology. Point diffraction interferometry, which generates a spherical reference wave front by pinhole diffraction, has been developed to meet this need. In order to estimate the measurement accuracy, several scalar wave diffraction methods have been used when the diameter of the pinhole is much larger than the wavelength. However, while the diameter keeps decreasing, ultimately to the order of the wavelength, it is obviously not appropriate to calculate in the same way. So, a three-dimensional (3-D) electromagnetic field simulation, based on Finite Element Method (FEM), is set up to study the propagation of the visible- light, 632.8 nm wavelength, through sub- 1000nm diameter pinholes in a chromium membrane. Deviations have been calculated to predict the accuracy, between perfect sphere and the wave front, diffracted by a series of pinholes with different diameters.

Paper Details

Date Published: 16 November 2011
PDF: 7 pages
Proc. SPIE 8321, Seventh International Symposium on Precision Engineering Measurements and Instrumentation, 83211O (16 November 2011); doi: 10.1117/12.904713
Show Author Affiliations
Tingwen Xing, Institute of Optics and Electronics (China)
Jiajun Xu, Institute of Optics and Electronics (China)
Graduate School of the Chinese Academy of Sciences (China)
Fuchao Xu, Institute of Optics and Electronics (China)
Graduate School of the Chinese Academy of Sciences (China)


Published in SPIE Proceedings Vol. 8321:
Seventh International Symposium on Precision Engineering Measurements and Instrumentation
Kuang-Chao Fan; Man Song; Rong-Sheng Lu, Editor(s)

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