Laser & Optoelectronics Progress, Volume. 52, Issue 12, 122207(2015)
Tolerance Analysis of High-Numerical Aperture Extreme Ultraviolet Lithographic Objective
High-numerical aperture (NA>0.45) extreme ultraviolet lithography is a promising candidate for 11 nm node lithography, and the tolerances of the objective system are rigorous due to high resolution image. The singular value decomposition (SVD) of the sensitivity matrix from sensitive mirrors is used to select efficient compensators for an extreme ultraviolet (EUV) lithographic objective with a numerical aperture of 0.50. The method requires that the amounts of configuration parameters is less than that of the aberration parameters, so the sensitive mirrors are confirmed and the sensitivity matrix is obtained by the configuration parameters of the sensitive mirrors. Then the sensitive and efficient compensators are selected to relax the other tolerances and compensate the worse of image quality by using the SVD of the sensitivity matrix. Using the above method, eight compensators are selected and other tolerances are assigned. Result shows that the RMS wavefront error of the objective system is less than 0.5 nm in the probability of 97.7% and the most rigorous tolerances are in the range of micron and microradian respectively.
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Sun Yuanyuan, Li Yanqiu, Cao Zhen. Tolerance Analysis of High-Numerical Aperture Extreme Ultraviolet Lithographic Objective[J]. Laser & Optoelectronics Progress, 2015, 52(12): 122207
Category: Optical Design and Fabrication
Received: Jul. 1, 2015
Accepted: --
Published Online: Dec. 8, 2015
The Author Email: Yuanyuan Sun (2120130566@bit.edu.cn)