Aberration control for advanced step-and-scan systems using pupil plane engineering

Harry Sewell; Daniel R. Cote; Andrew Guzman; Carlo Lafiandra; Tim O'Neil

doi:10.1117/12.435756

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14 September 2001 Aberration control for advanced step-and-scan systems using pupil plane engineering

Harry Sewell, Daniel R. Cote, Andrew Guzman, Carlo Lafiandra, Tim O'Neil

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Proceedings Volume 4346, Optical Microlithography XIV; (2001) https://doi.org/10.1117/12.435756
Event: 26th Annual International Symposium on Microlithography, 2001, Santa Clara, CA, United States

Abstract

This paper examines the control of optical aberrations in an advanced step-and-scan system that uses catadioptric projection optics. Optical lithography will be required to print pattern features down to the 50 nm range. To achieve 50 nm, optical lithography will need to operate at K-factors approaching 0.25 using 193 nm and 157 nm wavelengths with extremely high numerical apertures. Controlling aberrations in the optics will be critical to advanced lithography tools. The significant advantages of catadioptric compared with refractive optics are highlighted. In a catadioptric system, the pupil plane of the optics can be close to a mirror plane; this allows the unique capability to directly access the pupil plane for aberration measurement and adjustment. This paper demonstrates how a catadioptric step-and-scan system uses pupil-plane engineering to reduce aberrations to new levels, lower levels than ever possible before. The aberration control is demonstrated for the advanced optical techniques that are required to support K-factors approaching 0.25. Aberration control for 100 nm lithography on a 0.75NA 193 nm system is reviewed, and pupil-plane engineering is demonstrated. Pupil planes are mapped, and the aberration sensitivities are indicated. This paper concludes that wavefront engineering is the shape of things to come in the world of advanced lithography and system matching.

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Harry Sewell, Daniel R. Cote, Andrew Guzman, Carlo Lafiandra, and Tim O'Neil "Aberration control for advanced step-and-scan systems using pupil plane engineering", Proc. SPIE 4346, Optical Microlithography XIV, (14 September 2001); https://doi.org/10.1117/12.435756

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