Laser produced plasma light source for EUVL

Fomenkov, Igor V.; Ershov, Alex I.; Partlo, William N.; Myers, David W.; Brown, Daniel J.; Sandstrom, Richard L.; Fontaine, Bruno La; Bykanov, Alexander N.; Vaschenko, G.; Khodykin, Oleh V.; Böwering, N.; Das, Palash; Fleurov, Vladimir B.; Zhang, Kevin; Srivastava, Shailendra N.; Ahmad, Imtiaz; Rajyaguru, Chirag; Dea, Silvia De; Hou, Richard R.; Dunstan, Wayne J.; Baumgart, P.; Ishihara, Toshihiko; Simmons, Rod D.; Jacques, Robert N.; Bergstedt, Robert; Brandt, David C.

doi:10.1117/12.882210

Cited by 8 publications

(5 citation statements)

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“…Current EUV source operations reflect the results of these measurements, however, as liters of buffer gas per minute are now injected into the source, and chamber pressures are held upwards of 1 Torr. 5…”

Section: Resultsmentioning

confidence: 99%

“…Because 13.5-nm light is readily absorbed at atmospheric gas pressures and by nearly all materials, it is necessary to maintain a low-pressure hydrogen (used for its low absorption of EUV radiation) gas environment, as well as to get rid of the pellicle currently placed between the DUV light source and the collector optics. [4][5][6] Getting rid of the pellicle consequently requires alternative methods to prevent the energetic ions and neutrals (up to 50 keV) from damaging the collector optics used to focus EUV photons onto the intermediate focus (IF). Such efforts seek to extend the lifetime of the collector optics and reduce the cost of ownership of a tool.…”

Section: Introductionmentioning

confidence: 99%

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Debris transport analysis at the intermediate focus of an extreme ultraviolet light source

Sporre

Ruzic

2012

J. Micro/Nanolith. MEMS MOEMS

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As extreme ultraviolet light lithography matures, critical deficits in the technology are being resolved. Research has largely focused on solving the debris issue caused by using warm (Te ∼ 30 eV) and dense (n e ∼ 10 20 cm −3) plasma to create 13.5-nm light. This research has been largely focused on the mitigation of the debris between the plasma and the collector optics. The next step of debris mitigation is investigated, namely the effect of debris mitigation on the transport of undesired contaminants to the intermediate focus (IF). In order to investigate emissions from the IF, the Center for Plasma-Material Interactions at the University of Illinois at Urbana-Champaign has developed the Sn intermediate focus flux emission detector. The effects of a secondary RF-plasma, buffer gas flow rate, chamber pressure, and charged plate deflection are investigated. By increasing the chamber pressure to 10 mTorr, flowing 1000 sccm Ar buffer gas, and utilizing charged particle deflection, it is possible to reduce the measured number of post-IF species by greater than 99%. Furthermore, it is shown that typical debris mitigation techniques lead to the development of a plasma near the IF that can be detrimental to post-IF optics.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Debris transport analysis at the intermediate focus of an extreme ultraviolet light source

Sporre

Ruzic

2012

J. Micro/Nanolith. MEMS MOEMS

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“…Lenses – there has been redesign of the lenses utilising multi‐layer mirrors, still it is reported to absorb 30% of the light; gases – vacuum has to be maintained for entire light path to further avoid any dissipation. The power at which the LPP system can continuously run affects the high‐volume manufacturing targets [11, 12].…”

Section: Illumination Opticsmentioning

confidence: 99%

Lithography technology for advanced devices and introduction to integrated CAD analysis for hotspot detection

Vikram

Agarwal

2017

IET Circuits, Devices & Systems

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Optical projection lithography has been the workhorse of the integrate circuit (IC) manufacturing industry to transfer the computer-aided design (CAD) to semiconducting material wafers. The resolution limit of the 193 nm wavelength lithography which was initially targeted for the 90 nm design rule has been further extended to realise ∼10-20 nm devices with ingenious interventions. The three-dimensional fin-shaped field-effect transistor device structure now realise the <20 nm design rule still using 193 nm projection lithography as the widely accepted solution. The extreme ultraviolet wavelength source systems are still in development and testing phases with some recent success reported, but still falling short of supporting volume production requirements. This study reviews the current trends in lithography and the associated resolution enhancement techniques with brief introduction to an integrated CAD analysis for hotspot detection.

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“…In this letter we propose a novel pre-pulse scheme consisting of a picosecond pulse pair at 1064 nm, which decreases the amount of undesirable fast ions, avoids back-reflections to the lasers and enables one to tailor the target shape.In the past two decades a large number of theoretical and experimental studies have been conducted on possible light sources for EUV lithography, including synchrotron radiation [2, 3], free-electron lasers [4,5], plasma sources [6-10] and high-harmonic generation [11]. From the aforementioned solutions, a tin-based laser-produced plasma source received the most attention due to its high conversion efficiency, robustness and scalability [12,13], resulting in a first commercial machine launched in 2010. In such an LPP source, narrowband radiation around 13.5 nm comes from multiple ionic states, Sn 8+ to Sn 14+ [14,15], collisionally excited by plasma electrons heated through interaction with a powerful CO2 laser.…”

mentioning

confidence: 99%

Controlling ion kinetic energy distributions in laser produced plasma sources by means of a picosecond pulse pair

Stodolna

Pinto

Ali

et al. 2018

Journal of Applied Physics

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The next generation of lithography machines uses extreme ultraviolet (EUV) light originating from laser-produced plasma (LPP) sources, where a small tin droplet is ionized by an intense laser pulse to emit the requested light at 13.5 nm. Numerous irradiation schemes have been explored to increase conversion efficiency (CE), out of which a double-pulse approach comprising a weak picosecond Nd:YAG pre-pulse followed by a powerful pulse is considered to be very promising [1]. Nevertheless, even for such CE-optimized schemes, ion debris ejected from the plasma with kinetic energies up to several keV remain a factor that hampers the maximum performance of LPP sources. In this letter we propose a novel pre-pulse scheme consisting of a picosecond pulse pair at 1064 nm, which decreases the amount of undesirable fast ions, avoids back-reflections to the lasers and enables one to tailor the target shape.In the past two decades a large number of theoretical and experimental studies have been conducted on possible light sources for EUV lithography, including synchrotron radiation [2, 3], free-electron lasers [4,5], plasma sources [6-10] and high-harmonic generation [11]. From the aforementioned solutions, a tin-based laser-produced plasma source received the most attention due to its high conversion efficiency, robustness and scalability [12,13], resulting in a first commercial machine launched in 2010. In such an LPP source, narrowband radiation around 13.5 nm comes from multiple ionic states, Sn 8+ to Sn 14+ [14,15], collisionally excited by plasma electrons heated through interaction with a powerful CO2 laser. An effective coupling between laser light and plasma occurs near the critical density, which for CO2-laser-driven plasma is around 10 19 cm -3 , meaning that a mass-limited tin target should be expanded to reduce its density. At the same time the size of the EUV source cannot be too large to match the requirements for the maximum etendue [16]. The precise control of the target shape is thus crucial for the production of EUV light in an industrial setting.

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Laser produced plasma light source for EUVL

Cited by 8 publications

References 0 publications

Debris transport analysis at the intermediate focus of an extreme ultraviolet light source

Debris transport analysis at the intermediate focus of an extreme ultraviolet light source

Lithography technology for advanced devices and introduction to integrated CAD analysis for hotspot detection

Controlling ion kinetic energy distributions in laser produced plasma sources by means of a picosecond pulse pair

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