Review of resist-based flare measurement methods for extreme ultraviolet lithography

Sun, Lei; Wood, O. R.; Verduijn, Erik; Singh, Mandeep; Wang, Wenhui; Kim, Ryoung-Han; Mangat, Pawitter J. S.; Koh, Hui Peng; Levinson, Harry

doi:10.1117/1.jmm.12.4.042001

Cited by 7 publications

(4 citation statements)

References 29 publications

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“…Although the EUV alpha-demo tool and beta tool (NXE:3100) suffered from more than 10% flare, NXE:3400 and newer tools exhibit much less flare. 18,19 This situation makes BF masks as a promising option for EUVL. BF masks were also evaluated in imec and found to benefit the lithographic process window.…”

Section: Bright-field Mask Studied At Imecmentioning

confidence: 99%

“…Flare values of EUV exposure systems have decreased for more than 20 years thanks to extreme efforts at removing optical component imperfections. Although the EUV alpha-demo tool and beta tool (NXE:3100) suffered from more than 10% flare, NXE:3400 and newer tools exhibit much less flare 18 , 19 . This situation makes BF masks as a promising option for EUVL.…”

Section: Introductionmentioning

confidence: 99%

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Mask absorber, mask tone, and wafer process impact on resist line-edge-roughness

Ohtomi,

Philipsen,

Welling

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

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.A high-numerical-aperture (NA) extreme ultraviolet lithography (EUVL) system has been highly desired and is now under construction at imec-ASML High NA Laboratory in Veldhoven. However, there are still many challenges to realizing high-volume manufacturing by High NA EUVL. Line edge roughness (LER) mitigation is one of the key elements. In our previous research, we studied how the normalized image log slope (NILS) and resist film thickness affect resist LER by exposure at NA 0.33 on NXE:3400 and S-Litho EUV. However, the mask absorber, mask tone, exposure dose, and postexposure bake (PEB) temperature were not the subject of previous investigations for decreasing LER. They have the potential to mitigate resist roughness such as illumination and resist thickness studied previously. Unbiased LER values of metal oxide resists (MOR) were experimentally measured on a half-pitch (hp) 14 nm line and space under several mask absorber/tonality, dose, and PEB temperature values. Per the mask absorber/tone, the NILS was varied using different illumination shapes. Low-n masks exhibited a higher NILS for the same illumination shape, which resulted in lower resist LER on the wafer. It was also found that the mask tone can contribute to LER mitigation. According to detailed investigations about the mask roughness, mask error enhancement factor, and flare by critical dimension scanning electron microscope (CD-SEM) measurements and S-Litho EUV, the most likely reason for the LER difference is a flare increase given by mask tone changes. From the dose and PEB temperature variation study, dose was apparently more dominant in resisting roughness than PEB temperature.

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Section: Bright-field Mask Studied At Imecmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mask absorber, mask tone, and wafer process impact on resist line-edge-roughness

Ohtomi,

Philipsen,

Welling

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

View full text Add to dashboard Cite

show abstract

“…Flare values of EUV exposure systems have been decreased for more than 20 years thanks to extreme efforts for removing imperfections of optical components. Whereas EUV alpha-demo tool and beta tool (NXE:3100) had been suffered from more than 10 % flare, NXE:3400 and newer ones indicated much less flare [17][18] . These days, BF masks were also evaluated in imec, which demonstrated its benefit on process window [7][8][9] .…”

Section: Bright-field (Bf) Mask Studied In Imecmentioning

confidence: 99%

Mask absorber/tone and process impact on resist line-edge-roughness

Ohtomi

Philipsen²,

Severi

et al. 2023

Optical and EUV Nanolithography XXXVI

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High numerical-aperture (NA) extreme ultraviolet lithography (EUVL) system has been highly desired [1-3] and is now under construction at imec-ASML high-NA laboratory in Veldhoven. However, there are still many challenges to realize high-volume manufacturing (HVM) by high-NA EUVL; Line edge roughness (LER) mitigation is one of the key elements. In our previous research, we studied how normalized image log slope (NILS) and resist film thickness (FT) affect resist LER by exposure at NA 0.33 on NXE:3400 and S-Litho EUV [4] . However, mask absorber/tone, exposure dose and postexposure bake (PEB) temperature were not focused on for decreasing LER. They have the potential to mitigate resist roughness as illumination and resist thickness also have. Unbiased LER (uLER) values of metal oxide resists (MOR) were experimentally measured on half pitch 14 nm line and space (L/S) under several mask absorber/tonality, dose and PEB temperature. Per mask absorber/tone the NILS was varied by using different illumination shapes. Low-n masks exhibited higher NILS for the same illumination shape, which resulted in lower resist LER on wafer. It was also found that mask tone can contribute to LER mitigation. According to detailed investigations about mask roughness, mask error enhancement factor (MEEF) and flare by CD-SEM measurements and S-Litho EUV, the most likely reason for LER difference is flare increase given by mask tone change. From dose and PEB temperature variation study, dose was apparently more dominant to resist roughness than PEB temperature.

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“…A typical projection system consists of 28 fused silica lenses, and 7 of them are aspherical lenses with a maximum diameter of 280 mm [46]. It should be noted that, in the case of lithography optics, the specification for surface roughness measurement is further subdivided into middle spatial frequency range (MSFR), high spatial frequency range (HSFR), and extended HSFR [47,48]. Carl Zeiss has investigated the influence of errors in different frequency bands on the performance of optical systems [49].…”

Section: State-of-the-art Precision Levelmentioning

confidence: 99%

Manufacturing technologies toward extreme precision

Zhang

Yan

Kuriyagawa

2019

Int. J. Extrem. Manuf.

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Precision is one of the most important aspects of manufacturing. High precision creates high quality, high performance, exchangeability, reliability, and added value for industrial products. Over the past decades, remarkable advances have been achieved in the area of high-precision manufacturing technologies, where the form accuracy approaches the nanometer level and surface roughness the atomic level. These extremely high precision manufacturing technologies enable the development of high-performance optical elements, semiconductor substrates, biomedical parts, and so on, thereby enhancing the ability of human beings to explore the macro- and microscopic mysteries and potentialities of the natural world. In this paper, state-of-the-art high-precision material removal manufacturing technologies, especially ultraprecision cutting, grinding, deterministic form correction polishing, and supersmooth polishing, are reviewed and compared with insights into their principles, methodologies, and applications. The key issues in extreme precision manufacturing that should be considered for future R&D are discussed.

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Review of resist-based flare measurement methods for extreme ultraviolet lithography

Cited by 7 publications

References 29 publications

Mask absorber, mask tone, and wafer process impact on resist line-edge-roughness

Mask absorber, mask tone, and wafer process impact on resist line-edge-roughness

Mask absorber/tone and process impact on resist line-edge-roughness

Manufacturing technologies toward extreme precision

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