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Optical Engineering

Improved four-mirror optical system for deep-ultraviolet submicrometer lithography
Author(s): Jong-Tae Kim; Hong-Jin Kong; Sang-Soo Lee
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Paper Abstract

The design for a rotationally symmetric four-mirror optical system with reduction magnification 5 x for deep UV (λ = 248 nm of a KrF excimer laser) submicrometer lithography is developed. Initially by using the paraxial quantities, numerical solutions are found for the system, which is free from the four off-axial third-order aberrations-coma, astigmatism, field curvature, and distortion. Aspherization is carried out to the spherical mirror surfaces to reduce the axial and residual off-axial higher order aberrations. The numerical aperture of the final system is as large as 0.38, which gives a Rayleigh resolution of 0.4 μm and hence is useful in submicrometer lithographic applications.

Paper Details

Date Published: 1 March 1993
PDF: 6 pages
Opt. Eng. 32(3) doi: 10.1117/12.61056
Published in: Optical Engineering Volume 32, Issue 3
Show Author Affiliations
Jong-Tae Kim, Korea Advanced Inst. of Science and Technology (South Korea)
Hong-Jin Kong, Korea Advanced Institute of Science and Technology (South Korea)
Sang-Soo Lee, Korea Advanced Institute of Science & Technology (South Korea)

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