Suppression of suprathermal ions from a colloidal microjet target containing SnO2 nanoparticles by using double laser pulses

Higashiguchi, Takeshi; Kaku, Masanori; Katto, Masahito; Kubodera, Shoichi

doi:10.1063/1.2799175

Cited by 21 publications

(25 citation statements)

References 16 publications

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“…The Sn-3d intensities linearly increased with the increase of the laser pulses as expected. They represent similar values each other regardless of the irradiation modes, which showed a contrast to the ionic debris that was well suppressed by the double pulse irradiation [9]. These are unexpected results, indicating that ionic debris amount was very limited among the deposited debris amount.…”

Section: Introductionsupporting

confidence: 72%

“…As a result, the EUV conversion efficiency of 1.2% at 13.5 nm was achieved [8], which was almost equal to that of using a planar tin target. By employing the double pulse irradiation, the kinetic energy and intensity of emitted ionic debris were both decreased [9]. This observation was important to construct practical EUV sources, since low-energy ionic debris could be screened out by using a static electric-and/or magneticfield shielding [10].…”

Section: Introductionmentioning

confidence: 98%

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EUV and debris characteristics of a laser-plasma tin dioxide nano-particle colloidal jet target

et al. 2008

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Debris characteristics and its reduction have been investigated for a laser-produced plasma (LPP) extreme ultraviolet (EUV) source using a colloidal jet target containing tin dioxide nano-particles. Dominant deposited debris on a witness plate was found to have a form of oxidized tin (SnO x ) originated from nano-particles. Quantitative debris amounts were determined by total laser energy irradiated onto a target, not by laser irradiation modes, such as single or double pulse irradiation. In-situ low-temperature (100 °C) heating of a plate was effective to reduce the deposited debris amount, since colloidal debris was easily vaporized by the heat. Another approach to remove the deposited debris was roomtemperature photon processing using incoherent vacuum ultraviolet (VUV) emission at 126 nm. X-ray photoelectron spectroscopy (XPS) analysis has shown that the deposited SnO x debris layer was deoxidized by the 126 nm VUV photon energy.

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Section: Introductionsupporting

confidence: 72%

Section: Introductionmentioning

confidence: 98%

EUV and debris characteristics of a laser-plasma tin dioxide nano-particle colloidal jet target

et al. 2008

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“…22 It was also shown that LPPs exhibit preferential emission close to target normal; the energy of the ions emitted close to the target normal were also higher than that of ions emitted at larger angles. 23 Higashiguchi et al 24 demonstrated suppression of suprathermal ions from a colloidal microjet target plasma containing tin-dioxide (SnO 2 ) nanoparticles irradiated by double laser pulses. As a result, the peak energy of the singly ionized tin ions was reduced from 9 to 3 keV.…”

mentioning

confidence: 99%

“…As a result, the peak energy of the singly ionized tin ions was reduced from 9 to 3 keV. 24 The optimized EUV productions need plasma with appropriate ion populations, which depend strongly on plasma density and temperature. The average charge state Z of an LPP is related to ion kinetic energy (E) and plasma temperature (T e ).…”

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confidence: 99%

Influence of laser pulse duration on extreme ultraviolet and ion emission features from tin plasmas

et al. 2014

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We investigated the role of laser pulse duration and intensity on extreme ultraviolet (EUV) generation and ion emission from a laser produced Sn plasma. For producing plasmas, planar slabs of pure Sn were irradiated with 1064 nm Nd:YAG laser pulses with varying pulse duration (5–20 ns) and intensity. Experimental results performed at CMUXE indicate that the conversion efficiency (CE) of the EUV radiation strongly depend on laser pulse width and intensity, with a maximum CE of ∼2.0% measured for the shortest laser pulse width used (5 ns). Faraday Cup ion analysis of Sn plasma showed that the ion flux kinetic profiles are shifted to higher energy side with the reduction in laser pulse duration and narrower ion kinetic profiles are obtained for the longest pulse width used. However, our initial results showed that at a constant laser energy, the ion flux is more or less constant regardless of the excitation laser pulse width. The enhanced EUV emission obtained at shortest laser pulse duration studied is related to efficient laser-plasma reheating supported by presence of higher energy ions at these pulse durations.

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“…We believe that the shape of the Sn target is crucial [8][9][10][11][12]. To realize this, a double-laser irradiation process is utilized in our system.…”

Section: Double-pulse Laser Irradiation When a Sn Droplet Target Is mentioning

confidence: 99%

Development of Laser-Produced Tin Plasma-Based EUV Light Source Technology for HVM EUV Lithography

Fujimoto¹,

Hori²,

Yanagida³

et al. 2012

Physics Research International

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Since 2002, we have been developing a carbon dioxide (CO 2 ) laser-produced tin (Sn) plasma (LPP) extreme ultraviolet (EUV) light source, which is the most promising solution because of the 13.5 nm wavelength high power (>200 W) light source for high volume manufacturing. EUV lithography is used for its high efficiency, power scalability, and spatial freedom around plasma. We believe that the LPP scheme is the most feasible candidate for the EUV light source for industrial use. We have several engineering data from our test tools, which include 93% Sn ionization rate, 98% Sn debris mitigation by a magnetic field, and 68% CO 2 laser energy absorption rate. The way of dispersion of Sn by prepulse laser is key to improve conversion efficiency (CE). We focus on prepulsed laser pulsed duration. When we have optimized pulse duration from nanosecond to picosecond, we have obtained maximum 4.7% CE

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Suppression of suprathermal ions from a colloidal microjet target containing SnO2 nanoparticles by using double laser pulses

Cited by 21 publications

References 16 publications

EUV and debris characteristics of a laser-plasma tin dioxide nano-particle colloidal jet target

EUV and debris characteristics of a laser-plasma tin dioxide nano-particle colloidal jet target

Influence of laser pulse duration on extreme ultraviolet and ion emission features from tin plasmas

Development of Laser-Produced Tin Plasma-Based EUV Light Source Technology for HVM EUV Lithography

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