Characteristics and prevention of pattern collapse in EUV lithography

Chang, Wook; Kim, Eun Jin; Kang, Young-Min; Park, Seung-Wook; Lim, Chang-Moon; Won, Kitak; Kim, Jaisoon; Oh, Hye−Keun

doi:10.1117/12.712469

Cited by 2 publications

(3 citation statements)

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“…In this unified graph, each datapoint represents the averaged results of 50 images with the different number of frames (4, 8, 16, 32, and 64) for both the SOG and UL. In this graph, we observe two effects: (1) an increased dependence of uLWR on SNR when reducing the resist FT and (2) a characteristic response curve for each resist FT, where uLWR increases when reducing the resist FT.…”

Section: Snr and Frame Variationmentioning

confidence: 98%

“…To accomplish this, the semiconductor industry has witnessed the transition from contact and proximity printing in the 1970s to a range of projection lithography techniques. The drastic resolution improvement in projection lithography has been enabled by three main factors: (1) the reduction of imaging source wavelength λ, (2) the increase in the lens numerical aperture (NA), and (3) the reduction of the process-related k 1 -factor, that are summarized in the Rayleigh equation, where HP represents the smallest possible half-pitch: *Address all correspondence to Joren Severi, joren.severi@imec.be…”

Section: Introductionmentioning

confidence: 99%

“…These large aspect ratios would otherwise cause pattern collapse during the development of the exposed resist lines due to capillary forces during the rinse process. 1 The further instrumental development toward smaller feature sizes in EUV lithography (EUVL) is based on the implementation of a larger NA. 2 This NA relates to the range of angles that the lens or mirror can accept: E Q -T A R G E T ; t e m p : i n t r a l i n k -; e 0 0 2 ; 1 1 6 ; 5 8 0 NA ¼ n sinðθÞ:…”

Section: Introductionmentioning

confidence: 99%

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Chemically amplified resist CDSEM metrology exploration for high NA EUV lithography

Severi

Lorusso

Simone

et al. 2022

J. Micro/Nanopattern. Mats. Metro.

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Background: The chemically amplified resist (CAR) has been the workhorse of lithography for the past few decades. During the evolution of projection lithography to extreme ultraviolet lithography (EUVL), a continuous reduction in feature size is observed. Also, a reduction in resist film thickness (FT) is required to prevent large aspect ratios that lead to pattern collapse. A further reduction in resist FT, into an ultrathin film regime (<30 nm resist FT), is expected when advancing to high NA EUVL. This brings along associated challenges with (1) resist critical dimension scanning electron microscope (CDSEM) metrology and (2) resist patterning performance.Aim: Assessment of metrology challenges and patterning limits of a CAR working in this ultrathin film regime. Deconvoluting the metrology and patterning effect on the determination of the unbiased line width roughness (uLWR).Approach: Patterning a CAR at different nominal resist FTs on two different underlayers to quantify the changes in CDSEM image quality and resist patterning performance with the resulting uLWR changes. Results:The CDSEM image signal-to-noise ratio (SNR) depends on resist FT and the underlayer. The uLWR increases with a reduction in resist FT but scales differently on the two underlayers.Conclusions: A relationship between CDSEM image SNR and uLWR is found. The SNR and uLWR scaling difference on the two underlayers, as well as the uLWR dependency on SNR was determined to be a metrology effect. The general uLWR increase for a reduced resist FT was determined to be a patterning effect.

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Section: Snr and Frame Variationmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Chemically amplified resist CDSEM metrology exploration for high NA EUV lithography

Severi

Lorusso

Simone

et al. 2022

J. Micro/Nanopattern. Mats. Metro.

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e-beam metrology of thin resist for high NA EUVL

Lorusso

Simone

zidan

et al. 2023

Jpn. J. Appl. Phys.

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One of the many constrains of High Numerical Aperture Extreme Ultraviolet Lithography (High NA EUVL) is related to resist thickness. In fact, a critical consequence of moving from current 0.33NA to 0.55NA (High NA) is Depth of Focus (DOF) reduction. The question we seek to answer in the present work is how the resist thickness reduction impacts the e-beam metrology needed to characterize the process. The impact of film thickness on e-beam metrology was first investigated by Critical Dimension Scanning Electron Microscope (CD SEM) using our current Best-Known Methods (BKM’s). Optimized settings minimizing such an impact were then investigated using CD SEM as well as Low Voltage SEM (LV SEM). Atomic Force Microscopy (AFM) was used to accurately characterize the samples thickness. Our results indicates that alternative operating conditions and BKM’s are sometimes needed to meet the metrology requirements. However, even in the case of materials showing a large sensitivity to resist thinning, we were able to identify e-beam imaging conditions able to meet metrology specifications.

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Characteristics and prevention of pattern collapse in EUV lithography

Cited by 2 publications

References 0 publications

Chemically amplified resist CDSEM metrology exploration for high NA EUV lithography

Chemically amplified resist CDSEM metrology exploration for high NA EUV lithography

e-beam metrology of thin resist for high NA EUVL

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