Magnetic field ion mitigation for EUV light sources

Komori, Hiroshi; Imai, Yousuke; Soumagne, Georg; Abe, Tamotsu; Suganuma, Takashi; Endo, Akira

doi:10.1117/12.600360

Cited by 21 publications

(7 citation statements)

References 11 publications

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“…16 The effectiveness of the magnetic field ion mitigation was evaluated by measuring the erosion rate with a quartz crystal microbalance. 21 A significant decrease of the Faraday cup (FC) signal was monitored by applying a magnetic field of 0.6 T. Target size dependence on magnetic field effectiveness was observed, measured erosion rate was reduced to less than 10% by applying 0.6 T magnetic field in the case of 10-lm Xe jet and 300-mJ Nd:YAG laser irradiation. 21 It was shown that with Nd:YAG laser and Sn rod target the fast ion signal decreased to <0.1% with 1 T magnetic flux density.…”

Section: Introductionmentioning

confidence: 98%

“…21 A significant decrease of the Faraday cup (FC) signal was monitored by applying a magnetic field of 0.6 T. Target size dependence on magnetic field effectiveness was observed, measured erosion rate was reduced to less than 10% by applying 0.6 T magnetic field in the case of 10-lm Xe jet and 300-mJ Nd:YAG laser irradiation. 21 It was shown that with Nd:YAG laser and Sn rod target the fast ion signal decreased to <0.1% with 1 T magnetic flux density. 22 Experiments with Nd:YAG laser irradiation on Tin target showed that the kinetic energies of the plume species were considerably reduced even at short distances with a modest perpendicular magnetic field of 0.64 T. 23 Confinement and dynamics of laser-produced plasma expanding across a transverse magnetic field has been studied by many authors, [24][25][26][27][28][29] however, there are a very few a) Electronic addresses: roy@fzu.cz and aroy@barc.gov.in reports available for dynamics of plasma expanding along the direction of the magnetic field.…”

Section: Introductionmentioning

confidence: 98%

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Extreme ultraviolet emission and confinement of tin plasmas in the presence of a magnetic field

et al. 2014

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We investigated the role of a guiding magnetic field on extreme ultraviolet (EUV) and ion emission from a laser produced Sn plasma for various laser pulse duration and intensity. For producing plasmas, planar slabs of pure Sn were irradiated with 1064 nm, Nd:YAG laser pulses with varying pulse duration (5–15 ns) and intensity. A magnetic trap was fabricated with the use of two neodymium permanent magnets which provided a magnetic field strength ∼0.5 T along the plume expansion direction. Our results indicate that the EUV conversion efficiency do not depend significantly on applied axial magnetic field. Faraday Cup ion analysis of Sn plasma show that the ion flux reduces by a factor of ∼5 with the application of an axial magnetic field. It was found that the plasma plume expand in the lateral direction with peak velocity measured to be ∼1.2 cm/μs and reduced to ∼0.75 cm/μs with the application of an axial magnetic field. The plume expansion features recorded using fast photography in the presence and absence of 0.5 T axial magnetic field are simulated using particle-in-cell code. Our simulation results qualitatively predict the plasma behavior.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Extreme ultraviolet emission and confinement of tin plasmas in the presence of a magnetic field

et al. 2014

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“…13 Several studies have been conducted to devise new or to improve upon existing schemes to mitigate and/or decrease debris emission such as: mass-limited targets, 18,19 ambient gases, 20,21 and magnetic confinement. 19,22 Currently radiation from both Nd:YAG and CO 2 lasers are considered to be promising excitation sources for producing Sn plasmas and hence significant efforts are going into optimizing laser and target parameters to develop efficient and clean EUV light source. Hence it is imperative to have a detailed account of ion and neutral particle emission from these plasmas for developing efficient debris mitigation schemes.…”

Section: Introductionmentioning

confidence: 99%

The effect of laser wavelength on emission and particle dynamics of Sn plasma

Campos

Harilal

Hassanein

2010

Journal of Applied Physics

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We investigated the effects of laser wavelength on the atomic, ionic, and radiative emission from laser-produced tin plasmas. For generating plasmas, planar tin targets were excited using either high intensity neodymium-doped yttrium aluminum garnet ͑Nd:YAG, 1.06 m͒ or carbon dioxide ͑CO 2 , 10.6 m͒ laser pulses; both are considered to be potential excitation lasers for an extreme ultraviolet ͑EUV͒ lithography laser-produced plasma light source. Various diagnostic tools were utilized for investigating ionic, neutral, and radiative emission from Sn plasmas including Faraday cup, witness plate in conjunction with x-ray photoelectron spectroscopy ͑XPS͒, EUV, and visible emission spectroscopy and photography. Atomic and ionic analysis showed that the amount of debris emitted by the Nd:YAG generated plasmas was considerably higher than the CO 2 laser-produced plasmas. The angular distributions of both atomic and ionic debris were found to be more forward-centric for the 1.06 m generated plasma while being much more uniform for the 10.6 m heated plasma. EUV and visible emission images of the plasma also showed a forward-centric appearance for 1.06 m heated plasmas. The strength of excited neutral emission was considerably lower for the case of the 10.6 m plasma while the kinetic energies of ions debris were found to be much higher for CO 2 generated plasmas. Surface analysis of the craters created by the lasers showed that the mass ablation rate is 3.6 times higher for Nd:YAG laser generated plasmas compared to CO 2 generated plasmas at maximum EUV emission.

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“…Therefore, mitigation of the debris is of importance for the development of a practical EUV lithography system. Although several methods have been developed for the debris mitigation [5][6][7], the fundamental and general approach is the use of a minimum amount of Sn that can still provide a sufficient EUV power. This type of Sn target is called a mass-limited or a minimum-mass target [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Ablation dynamics of tin micro-droplet irradiated by double pulse laser used for extreme ultraviolet lithography source

Nakamura¹,

Akiyama²,

Okazaki³

et al. 2008

J. Phys. D: Appl. Phys.

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The ablation dynamics of a tin (Sn) micro-droplet by double pulse laser irradiation for the development of an extreme ultraviolet lithography source was investigated. The solid state Sn droplet target with a diameter of 30 µm was irradiated by double laser pulses from a Q-switched Nd : YAG laser and a CO2 laser, and the kinetic behaviour of debris such as Sn atoms, ions and of the dense particles from the droplet was investigated by the laser-induced fluorescence imaging method, Faraday cups and high-speed imaging, respectively. After the pre-pulse irradiation of the Nd : YAG laser, the ions were emitted towards the laser incident direction with an average kinetic energy of 3–6 keV and the dense particle cloud moved in the direction opposite to the laser incident direction with expansion by a reaction force due to the plasma expansion at a speed of approximately 500 m s−1. On the other hand, the Sn atoms were ejected in all directions from the target with a speed as fast as 20 km s−1. The expanding target was subsequently irradiated by the main pulse of the CO2 laser with a delay of 800 ns and the dense cloud almost disappeared due to main-pulse irradiation.

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Magnetic field ion mitigation for EUV light sources

Cited by 21 publications

References 11 publications

Extreme ultraviolet emission and confinement of tin plasmas in the presence of a magnetic field

Extreme ultraviolet emission and confinement of tin plasmas in the presence of a magnetic field

The effect of laser wavelength on emission and particle dynamics of Sn plasma

Ablation dynamics of tin micro-droplet irradiated by double pulse laser used for extreme ultraviolet lithography source

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