Analysis of Mid-Spatial Frequency Surface Errors Effects on Local Flare in Lithographic Projection Lens

Wang, 杨旺 Yang; Wei, 黄玮 Huang; Weicai, 许伟才 Xu; Hongbo, 尚红波 Shang

doi:10.3788/aos201333.0922001

Cited by 3 publications

(1 citation statement)

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“…The machining of aspherical surfaces is easier to accumulate mid-spatial frequency errors, especially. The mid-spatial frequency surface errors cause small-angle divergence of the beam energy, which causes short-range stray light [6] , thus affecting the penumbra width of the illumination field.…”

Section: Introductionmentioning

confidence: 99%

Effects of mid-spatial frequency errors of optical surface on the penumbra width of photolithography relay lens

Liu,

Zhang,

Huang

2023

AOPC 2023: Optical Design and Manufacturing

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Section: Introductionmentioning

confidence: 99%

Effects of mid-spatial frequency errors of optical surface on the penumbra width of photolithography relay lens

Liu,

Zhang,

Huang

2023

AOPC 2023: Optical Design and Manufacturing

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Dynamic budget analysis of multiple parameters in a lithography system based on the superposition of light intensity fluctuations

Wang,

Su,

Dong

et al. 2024

Opt. Express

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Lithography is one of the most critical processes in the manufacturing of micro- and nano-devices. As device critical dimensions continue to shrink, variations in system parameters during the lithography process often result in heavy deviations from the intended targets, making control of these parameters crucial to ensure that lithography results meet process requirements. Gaining a thorough comprehension of how various parameters interact and contribute to lithography errors is significant, and it is equally important to offer precise suggestions for managing these parameters in extreme ultraviolet lithography (EUVL) scanners. This paper analyzes the key physical factors in the light source, illumination system and projection system of EUVL scanners and proposes what we believe to be a new methodology of budget analysis utilizing the superposition of light intensity fluctuations. Then the corresponding characteristics of light intensity fluctuations are analyzed when these parameters have fluctuated through theoretical formula derivation. A mapping model was established between parameter fluctuations and imaging outcomes through the distribution of light intensity. The yield requirements for critical dimension and pattern shift in EUVL are used to determine the exact budget range for each parameter in the proposed methodology. By controlling the parameters according to the budget analysis method proposed in this paper, the deviation between the experimental results from the yield requirements is no more than 0.1% in average. This approach allows for dynamic updating of the control range of relevant parameters based on their distinct characteristics to accommodate the unique fingerprints of various EUVL scanners. Furthermore, based on this adaptive budget range of multiple parameters, it can offer distinct direction for the development of lithography equipment or serve as a clear indication for parameter monitoring.

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Method of controlling optical surface roughness based on stray light requirements

Song¹,

Yang²,

Fu³

et al. 2017

Acta Phys. Sin.

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Scattering introduced by optical surface fabrication errors could degrade optical performance severely. Therefore, the optical designers are required to provide a roughness index for describing the specific surface or even all surfaces to ensure the final imaging performance. The surface root-mean-square (RMS) roughness is a common index to quantify surface topography. And there are also some available methods to acquire the surface RMS roughness based on bidirectional scattering distribution function theory or the angle spread function theory. However, the influence of the optical surface scattering on the optical system cannot be accurately revealed by the surface RMS roughness determined by these methods. On the one hand, the RMS roughness corresponds to an excessively wide spatial frequency range from 0 to 1/, where is the wavelength of the light. Consequently, it is difficult to measure the RMS roughness during manufacture. On the other hand, what really worsens the stray light performance of the system is only the surface profile located within a certain subinterval of the aforementioned frequency range, to put it in another way, the surface RMS roughness identified by the methods above is incompetent to quantify the amount of the energy that is surfacescattered to the detector. To address the issues above, in this paper we propose a novel approach to identifying the surface roughness. This method seeks to deduce the relation between optical surface RMS roughness and the stray light requirement of the system by dint of partial integrated scattering (PIS). In contrast to total integrated scattering, PIS counts the scattering light energy that could reach the detector. Hence, the RMS roughness identified in this way corresponds to the effective spatial frequency range that contributes to the stray light in the system. Firstly, the effective frequency range concerned with the system stray light level is identified through the analysis of the propagation path of the scattered light. Then, the surface RMS roughness would be measured within the established range according to the stray light requirement of the system and used to control the surface roughness as the roughness index during the optical manufacture process. The method not only considers the scattering as the surface characteristic, but also takes into account the influence of scattering on the system. Taking the solar magnetic field telescope (MFT) for example, the validity of the method is verified by comparing with the traditional methods. As manifested in the outcome, the effective frequency range of primary mirror is from 0 to 18 mm-1, and the surface RMS roughness identified in such a new way can stage the stray light performance of MFT in a more precise manner, which is more reliable to serve as a surface roughness index.

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Analysis of Mid-Spatial Frequency Surface Errors Effects on Local Flare in Lithographic Projection Lens

Cited by 3 publications

References 0 publications

Effects of mid-spatial frequency errors of optical surface on the penumbra width of photolithography relay lens

Effects of mid-spatial frequency errors of optical surface on the penumbra width of photolithography relay lens

Dynamic budget analysis of multiple parameters in a lithography system based on the superposition of light intensity fluctuations

Method of controlling optical surface roughness based on stray light requirements

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