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Proceedings Paper

Development status of a 157-nm full-field scanner
Author(s): Hitoshi Nakano; Hideo Hata; Hideki Nogawa; Nobuyoshi Deguchi; Michio Kohno; Yuji Chiba
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Paper Abstract

157 nm lithography has made further progress over the past year, steadily advancing towards the realization of the 65 nm era. In particular, exposure tools have moved on to the assembly phase, with new functions and performance now under evaluation. This paper presents our technical progress in our 157nm full field exposure tool, focusing on two key technologies: projection optics and environmental control with highly purified gasses. The high NA projection optics were designed to meet accelerating demands for smaller geometries. A catadioptric system with a line-selected laser was chosen to solve the problem of chromatic aberrations. The birefringence effect caused by CaF2 has been reduced to acceptable levels by clocking and combining <111> and <100> oriented crystals. Polishing and optical coatings consisting of glass materials were completed at targeted accuracy. At the present time, assembly and tuning of the projection optics is being performed. A simulation based on the inspection data from each production step predicts that the desired image performance will be attained. The total efficiency of the exposure system is expected to be higher than previously announced, due to the improvement of both CaF2 transmittance and AR/HR coatings. One of two keys issues in environmental control is to purge the projection optics which are permanently sealed. Purging performance was tested using a mockup of the projection optics. The second issue is to purge the areas around reticles and wafers which are continually carried into and out of the exposure system. Using the actual platform, the wafer and reticle purging performance was evaluated. It has been demonstrated that both of our purging systems are effective in keeping the environment at minimum contamination levels. This contributes to the increase of throughput.

Paper Details

Date Published: 26 June 2003
PDF: 9 pages
Proc. SPIE 5040, Optical Microlithography XVI, (26 June 2003); doi: 10.1117/12.485509
Show Author Affiliations
Hitoshi Nakano, Canon Inc. (Japan)
Hideo Hata, Canon Inc. (Japan)
Hideki Nogawa, Canon Inc. (Japan)
Nobuyoshi Deguchi, Canon Inc. (Japan)
Michio Kohno, Canon Inc. (Japan)
Yuji Chiba, Canon Inc. (Japan)

Published in SPIE Proceedings Vol. 5040:
Optical Microlithography XVI
Anthony Yen, Editor(s)

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