Optical Design and Engineering

Illumination system with freeform fly’s eye to generate pixelated pupil prescribed by source-mask optimization in extreme ultraviolet lithography

[+] Author Affiliations
Jiahua Jiang, Qiuli Mei, Yanqiu Li, Yan Liu

Beijing Institute of Technology, Key Laboratory of Photoelectron Imaging Technology and System of Ministry of Education, School of Optoelectronics, Beijing, China

Opt. Eng. 56(6), 065101 (Jun 16, 2017). doi:10.1117/1.OE.56.6.065101
History: Received January 21, 2017; Accepted May 30, 2017
Text Size: A A A

Abstract.  Source-mask optimization (SMO) has emerged as a key technique for 7-nm node and beyond in extreme ultraviolet (EUV) lithography. The pupil required by SMO is usually pixelated, with a free choice of intensity per pixel. However, due to the discrete nature of the EUV illumination system, pupil intensity in current EUV SMO must also be discretized. An illumination system with a freeform fly’s eye that is able to generate the pixelated pupil is proposed. Clear apertures of the field facets in the fly’s eye are different from each other so that the intensity of each pixel on the pupil can meet the requirements of SMO. Each of the field facets is constructed with a freeform surface to get the required arc-shaped illuminated area on the reticle. A method integrated with a numerical method and an optimization process is used to design the freeform surface of the field facets. The simulation result of the design for a prescribed freeform pixelated pupil shows that the uniformity on the reticle is 96.4%, and the pupil intensity error is approximated to be 0.035. The results indicate that the system is effective in generating the required freeform pixelated pupil and reducing the restrictions imposed on the SMO process in EUV lithography.

Figures in this Article
© 2017 Society of Photo-Optical Instrumentation Engineers

Citation

Jiahua Jiang ; Qiuli Mei ; Yanqiu Li and Yan Liu
"Illumination system with freeform fly’s eye to generate pixelated pupil prescribed by source-mask optimization in extreme ultraviolet lithography", Opt. Eng. 56(6), 065101 (Jun 16, 2017). ; http://dx.doi.org/10.1117/1.OE.56.6.065101


Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Related Book Chapters

Topic Collections

Advertisement
  • Don't have an account?
  • Subscribe to the SPIE Digital Library
  • Create a FREE account to sign up for Digital Library content alerts and gain access to institutional subscriptions remotely.
Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).
Access This Proceeding
Sign in or Create a personal account to Buy this article ($15 for members, $18 for non-members).
Access This Chapter

Access to SPIE eBooks is limited to subscribing institutions and is not available as part of a personal subscription. Print or electronic versions of individual SPIE books may be purchased via SPIE.org.