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Journal of Micro/Nanolithography, MEMS, and MOEMS • Open Access

Designing projection objectives for 11-nm node of extreme ultraviolet lithography
Author(s): Zhen Cao; Yanqiu Li; Fei Liu

Paper Abstract

Extreme ultraviolet (EUV) lithography is a promising candidate for next-generation lithography. To achieve an 11-nm node, a six-mirror EUV projection objective with a numerical aperture (NA) of 0.5 is designed with the grouping design method. In this design, pupil obscuration is introduced to decrease the angular spread on the mirrors, which still makes the six-mirror objective with aspheric surfaces sufficient for aberration correction. The grouping design allocates the complexity of designing a whole system to each of the mirror groups and could compatibly apply to designing EUV projection objectives with obscuration. The ×8 reduction design serves as an example for illustrating the grouping design principles for this type of system. In addition, the specific design forms with different reductions are presented and discussed. Design of these six-mirror objective systems provides potential solutions for 11-nm node EUV lithography.

Paper Details

Date Published: 9 September 2014
PDF: 7 pages
J. Micro/Nanolith. 13(3) 033014 doi: 10.1117/1.JMM.13.3.033014
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 13, Issue 3
Show Author Affiliations
Zhen Cao, Beijing Institute of Technology (China)
Yanqiu Li, Beijing Institute of Technology (China)
Fei Liu, Beijing Institute of Technology (China)

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