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Proceedings Paper

Application and influence of aspheric surfaces in lithographic objectives design
Author(s): Bin Ma; Lin Li; Yifan Huang; Chang Jun; Baolin Du; Xing Han
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Paper Abstract

In semiconductor industry, exposure tools have been improved in resolution. 193 nm lithography is one of the promising technologies for the fabrication of critical dimension from 100 to 32 nm. The optical performance of projection lens is the key factor to realize high resolution pattern. This paper presents the design process of a refractive lithography projection lens utilizing aspheric surfaces. The objective, as built, has a numerical aperture of 0.75, a maximum astigmatism of 30 nm and a total focal plane deviation of 45 nm. With the assistant of resolution enhancement technology, image resolution can reach 90 nm. Aspheric surfaces can be used to correct aberrations, to make optical systems more compact, and in some cases to reduce cost. Systems with and without aspheric surfaces are compared in the paper so as to find their differences in aberrations and configuration. We found that aspheric surfaces dramatically decrease the RMS wavefront error from 3 nm to 1 nm. Differ in position of aspheres can be used to correct aperture dependent aberrations (spherical aberration), and to correct field dependent aberrations (distortion and field curvature). We explored the connection between position of aspheres and different aberrations by APS (Aspheric surfaces selecting factor). Aspheric surfaces also make the system more applicable by reducing the system volume and leaving proper edge thickness for mechanical structure.

Paper Details

Date Published: 22 October 2010
PDF: 7 pages
Proc. SPIE 7657, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Design, Manufacturing, and Testing of Micro- and Nano-Optical Devices and Systems, 76570A (22 October 2010); doi: 10.1117/12.866022
Show Author Affiliations
Bin Ma, Beijing Institute of Technology (China)
Lin Li, Beijing Institute of Technology (China)
Yifan Huang, Beijing Institute of Technology (China)
Chang Jun, Beijing Institute of Technology (China)
Baolin Du, Beijing Institute of Technology (China)
Xing Han, Beijing Institute of Technology (China)


Published in SPIE Proceedings Vol. 7657:
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Design, Manufacturing, and Testing of Micro- and Nano-Optical Devices and Systems

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