Understanding EUV-induced plasma and application to particle contamination control in EUV scanners

Kerkhof, Mark van de; Yakunin, A. M.; Kvon, Vladimir; Wetering, Ferdi van de; Cats, Selwyn; Heijmans, Luuk; Nikipelov, Andrey; Lassise, Adam; Banine, VY Vadim

doi:10.1117/12.2551020

Cited by 19 publications

(13 citation statements)

References 7 publications

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“…Assuming typical values for the plasma of = 1•10 20 ions/m 2 s, = 10 eV, and R = 5, the cleaning rate may be estimated from equation 1 at 7 nm/min, while the heat load may be estimated from equation 2 to be 0.5 kW/m 2 . It should be noted that in general ion energies should not exceed values in order of 20 eV to avoid sputtering damage to the substrate to be cleaned [12]. Table 1 shows a comparison between plasma and HRG.…”

Section: Introductionmentioning

confidence: 99%

Miniature plasma source for in situ extreme ultraviolet lithographic scanner cleaning

Kerkhof

Osorio

Krivtsun

et al. 2022

Journal of Vacuum Science &Amp; Technology B

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Extreme ultraviolet (EUV) lithography is the technology of choice for high-volume manufacturing of sub-10nm lithography. One of the challenges is to enable in situ cleaning of functional surfaces, such as sensors, fiducials and interferometer mirrors, without opening the scanner tool. Thermally created hydrogen radicals have been successfully used for this purpose. These sources have limited cleaning speed and a relatively high thermal load to the surface being cleaned. Here, we present an alternative plasma-based technique to simultaneously create hydrogen radicals and hydrogen ions. This results in significantly improved cleaning speed while simultaneously reducing the overall thermal load. As an additional benefit, this plasma source has a minimized and flexible building volume to allow easy integration into various locations in the EUV lithographic scanner.

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Section: Introductionmentioning

confidence: 99%

Miniature plasma source for in situ extreme ultraviolet lithographic scanner cleaning

Kerkhof

Osorio

Krivtsun

et al. 2022

Journal of Vacuum Science &Amp; Technology B

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“…Among various methods to protect the EUV mask from aerosol contaminants [7][8][9][10][11][12], shielding with a pellicle is considered to be one of the most efficient. The EUV pellicle is a membrane with low absorption around 13 nm, high mechanical and chemical stability [13,14].…”

Section: Introductionmentioning

confidence: 99%

Renewable Single-Walled Carbon Nanotube Membranes for Extreme Ultraviolet Pellicle Applications

Benavides¹,

Krasnikov²,

Gubarev³

et al. 2022

SSRN Journal

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“…It was found that the EUV-induced plasma in the scanner can be a major factor in releasing and transporting particles via electrostatic release and under-etching 9 . This plasma is the result of ionization of the protective hydrogen background gas in the scanner 10 . Besides direct impact on particles, the EUV-induced plasma can also interact with electrostatics in several ways: it can e.g.…”

Section: Introductionmentioning

confidence: 99%

Plasma-assisted discharges and charging in EUV-induced plasma

Kerkhof

Yakunin

Kvon

et al. 2021

J. Micro/Nanopattern. Mats. Metro.

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In the past years, EUV lithography scanner systems have entered High-Volume Manufacturing for state-of-the-art Integrated Circuits (IC), with critical dimensions down to 10 nm. This technology uses 13.5 nm EUV radiation, which is transmitted through a near-vacuum H2 background gas, imaging the pattern of a reticle onto a wafer. The energetic EUV photons excite the background gas into a low-density H2 plasma. The resulting plasma will locally change the near-vacuum into a conducting medium, and can charge floating surfaces and particles, also away from the direct EUV beam. This paper will discuss the interaction between EUV-induced plasma and electrostatics, by modeling and experiments. We show that the EUV-induced plasma can trigger discharges well below the classical Paschen limit. Furthermore, we demonstrate the charging effect of the EUV plasma on both particles and surfaces. Uncontrolled, this can lead to unacceptably high voltages on the reticle backside and the generation and transport of particles. We demonstrate a special unloading sequence to use the EUV-induced plasma to actively solve the charging and defectivity challenges.

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Understanding EUV-induced plasma and application to particle contamination control in EUV scanners

Cited by 19 publications

References 7 publications

Miniature plasma source for in situ extreme ultraviolet lithographic scanner cleaning

Miniature plasma source for in situ extreme ultraviolet lithographic scanner cleaning

Renewable Single-Walled Carbon Nanotube Membranes for Extreme Ultraviolet Pellicle Applications

Plasma-assisted discharges and charging in EUV-induced plasma

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