The primary requirement for the development of tools extreme ultraviolet lithography (EUVL) has been identification and optimization suitable sources. These sources must be capable producing hundreds watts (EUV) radiation within a wavelength bandwidth 2% centred on 13.5 nm, based availability Mo/Si multilayer mirrors (MLMs) with reflectivity ∼70% at this wavelength. Since, exception large scale facilities, such as free electron lasers, is only emitted from plasmas containing moderately to...

We have demonstrated a laser-produced plasma extreme ultraviolet source operating in the 6.5–6.7 nm region based on rare-earth targets of Gd and Tb coupled with Mo/B4C multilayer mirror. Multiply charged ions produce strong resonance emission lines, which combine to yield an intense unresolved transition array. The spectra these resonant lines around 6.7 (in-band: ±1%) suggest that in-band increases increased volume by suppressing hydrodynamic expansion loss at electron temperature about 50...

We demonstrate a table-top broadband emission water window source based on laser-produced high-Z plasmas. Resonance from multiply charged ions merges to produce intense unresolved transition arrays (UTAs) in the 2–4 nm region, extending below carbon K edge (4.37 nm). Arrays resulting n=4-n=4 transitions are overlaid with n=4-n=5 and shift shorter wavelength increasing atomic number. An outline of microscope design for single-shot live cell imaging is proposed bismuth plasma UTA source,...

We demonstrate an efficient extreme ultraviolet (EUV) source for operation at λ = 6.7 nm by optimizing the optical thickness of gadolinium (Gd) plasmas. Using low initial density Gd targets and dual laser pulse irradiation, we observed a maximum EUV conversion efficiency (CE) 0.54% 0.6% bandwidth (BW) (1.8% 2% BW), which is 1.6 times larger than 0.33% (0.6% BW) CE produced from solid target. Enhancement use low-density plasma attributed to reduction self-absorption effects.

An examination of the influence target composition and viewing angle on extreme ultraviolet spectra laser produced plasmas formed from tin doped planar targets is reported. Spectra have been recorded in 9–17nm region created by a 700mJ, 15ns full width at half maximum intensity, 1064nm Nd:YAG pulse using an absolutely calibrated 0.25m grazing incidence vacuum spectrograph. The absorption ions (SnI–SnX) plasma clearly seen shape peak feature 13.5nm, while density also to level radiation region.

Extreme ultraviolet lithography requires a light source at 13.5nm to match the proposed multilayer optics reflectivity. The impact of wavelength and power density on ion distribution electron temperature in laser-produced plasma is calculated for Nd:YAG CO2 lasers. A steady-state figure merit, optimize emission as function laser wavelength, shows an increase with laser. influence reduced considered one-dimensional radiation transport model, where more than twofold conversion efficiency over...

We have demonstrated an efficient extreme ultraviolet (EUV) source at 6.7 nm by irradiating Gd targets with 0.8 and 1.06 μm laser pulses of 140 fs to 10 ns duration. Maximum conversion efficiency 0.4% was observed within a 0.6% bandwidth. A Faraday cup ion yield time flight signals for ions from plasmas generated each laser. Ion kinetic energy lower shorter pulse durations, which yielded higher electron temperatures required EUV emission, due intensity. Picosecond were found be the best...

We characterize extreme ultraviolet (EUV) emission from mid-infrared (mid-IR) laser-produced plasmas (LPPs) of the rare-earth element Gd. The energy conversion efficiency (CE) and spectral purity in mid-IR LPPs at λL = 10.6 μm were higher than for solid-state 1.06 μm, because plasma produced is optically thin due to lower critical density, resulting a CE 0.7%. peak wavelength remained fixed 6.76 nm all laser intensities studied. Plasma parameters intensity 1.3×10(11) W/cm(2) was also...

Bright narrow band emission observed in optically thin plasmas of high-Z elements the extreme ultraviolet spectral region follows a quasi-Moseley's law. The peak wavelength can be expressed as λ=(21.86±12.09)×R∞−1×(Z−(23.23±2.87))−(1.52±0.12), where R∞ is Rydberg constant. varies from 13.5 nm to 4.0 atomic number, Z, increases Z = 50 83. range wavelengths available hot permits development bright laboratory-scale sources for applications including x-ray microscopy and absorption fine...

The photoabsorption spectrum of In II has been recorded in the 18-33 eV region using dual laser plasma (DLP) technique. Transitions from 4d105s2 ground state dominate with some contribution metastable 3P2, 3P1 and 3P0 levels excited 4d105s5p configuration also observed. were identified by comparison values obtained multiconfiguration Hartree-Fock calculations.

One key aspect in the drive to optimize radiative output of a laser-produced plasma for extreme ultraviolet lithography is radiation transport through plasma. In tin-based plasmas, 2% bandwidth at 13.5 nm predominantly due 4d-4f and 4p-4d transitions from range tin ions (Sn7+ Sn12+). The complexity configurations involved these such that line-by-line analysis is, computationally, extremely intensive. This work seeks model emission profiles each ion by treating transition arrays...

We have investigated the dependence of spectral behavior and conversion efficiencies rare-earth plasma extreme ultraviolet sources with peak emission at 6.7 nm on laser wavelength initial target density. The maximum efficiency was 1.3% a intensity 1.6×1012 W/cm2 an operating 1064 nm, when self-absorption reduced by use low density target. Moreover, lower-density results in narrower spectrum therefore improved purity. It is shown to be important and/or produce electron plasmas for efficient...

The photoabsorption spectrum of a tin laser-produced plasma has been recorded in the 23-33 eV region using dual laser technique. 4d→5p transitions from 4d105s25p ground state Sn II and 4d105s2 4d105s5p excited states III were observed new features identified with aid multiconfiguration Hartree-Fock calculations. relative intensities indicate departure local thermodynamic equilibrium conditions absorbing plasma.

Recent work on multilayer mirror development for beyond extreme ultraviolet lithography indicates that their optimum reflectivity occurs at either 6.63 nm or 6.66 which may be too short a wavelength Gd-based plasma sources. Calculations performed Tb12+ to Tb28+ ions show if the is fixed one of these values, Tb better source, though Gd capable providing greater intensity full reflection curve mirrors exploited. Theoretical simulation shows emission peaks close 6.51 an electron temperature 120 eV.

Lithography tools are being built and shipped to semiconductor manufacturers for high volume manufacturing using extreme ultraviolet lithography (EUVL) at a wavelength of 13.5 nm. This is based on the availability Mo/Si multilayer mirrors (MLMs) with reflectivity ∼70% this wavelength. Moreover, primary tool manufacturer, ASML, has identified 6.x nm, where x∼7, as choice so-called Beyond EUVL, La/B4C MLMs, theoretical reflectance approaching 80% The optimum sources have been laser produced...

Plasmas containing gadolinium have been proposed as sources for next generation lithography at 6.x nm. To determine the optimum plasma conditions, atomic structure calculations performed Gd11+ to Gd27+ ions which showed that n = 4 − resonance transitions overlap in 6.5–7.0 nm region. Plasma modeling calculations, assuming collisional-radiative equilibrium, predict temperature an optically thin is close 110 eV and maximum intensity occurs 6.76 under these conditions. The agreement between...

We report on the identification of optimum plasma conditions for a laser-produced source efficient coupling with multilayer mirrors at 6.x nm beyond extreme ultraviolet lithography. A small shift to lower energies peak emission Nd:YAG gadolinium plasmas was observed increasing laser power density. Charge-defined spectra were in electron beam ion trap (EBIT) studies and charge states responsible identified by use flexible atomic code (FAC). The EBIT displayed larger systematic wavelength...

Current research on sources for extreme ultraviolet lithography (EUVL) has converged the use of discharge or laser produced plasmas containing xenon, tin, lithium with tin showing by far most promise. Because their density, radiation transport from these is a major issue and accurate photoabsorption cross sections are required development plasma models needed to optimize conditions source operation. The relative EUV photoionization Sn I through IV have been measured comparison results many...

Efficiency optimization of a stable and debris free plasma source at 13.5 nm, is the forefront current extreme ultraviolet lithographic (EUVL) research efforts. To date, 1–2.5% soft x-ray conversion efficiencies (CEs) within 2% bandwidth (BW) around nm into 2π steradians have been attained experimentally for laser-produced plasmas containing Sn power densities 0.5–5 × 1011 W cm−2. In order to complement these experimental endeavours, we undertaken study CE, given wavelength regime, in...

Extreme ultraviolet spectra from a tin laser produced plasma have been recorded over range of angles between 20° and 90° the target normal. Absolute intensity measurements are presented both 2% band centered on 13.5nm total radiation emitted by 10 18nm. The in-band is seen to be relatively constant out an angle 60° normal, beyond which it drops off quite steeply. at wavelengths greater than strongly influenced self-absorption ions ranging 6+ 10+.

Development of laser-produced plasma “water window” sources poses a major challenge in x-ray research and most effort has focused on line for use with zone plate optics. Here, comparison carbon nitrogen emission that from both 3d – 4f 4d unresolved transition arrays shows that, at power densities available “table-top” solid-state lasers, zirconium plasmas is intense, calculations show an imaging system based multilayer mirrors, reflectance bandwidths >1% superior performance than...

We demonstrate efficient enhancement of soft X-ray (SXR) emission from molybdenum plasmas produced using dual pulse irradiation, in which 10-ns and 150-ps pre-pulses were followed by a main pulse. The number photons was observed to be 5.3 × 1016 photons/sr, corresponded conversion efficiency 1.5%/sr λ = 2.34–4.38 nm region at separation time 1 ns with the pre-pulse. became 1.3 times as large that single results indicate advantage irradiation sub-ns pre-and pulses produce bright required for...

The unresolved transition arrays (UTAs) emitted from laser produced bismuth (Bi) plasma sources show potential for single-shot live cell imaging. We have measured extreme ultraviolet spectra plasmas in the 1–7 nm region using a λ = 1064 Nd:YAG with pulse duration of 150 ps. Comparison obtained under different power densities calculations Hartree–Fock configuration interaction Cowan suite codes and UTA formalism, as well consideration previous predictions isoelectronic trends, are employed to...

A flat-field grazing incidence spectrometer operating on the spectral region from 1 to 10 nm was built for research physics of high temperature and energy density plasmas. It consists a grating with 2400 lines/mm as dispersing element an x-ray charged coupled device (CCD) camera detector. The diffraction efficiency sensitivity CCD were directly measured by use synchrotron radiation at BL-11D beamline Photon Factory (PF). influence contamination also characterized. This result enables us...

Spectra from xenon ions have been recorded at the NIST EBIT and emission into a 2% bandwidth 13.5 nm arising 4d_5p transitions compared with that 4d_4f 4p_4d in Xe XI also obtained unresolved transition array (UTA) observed to peak just below 11 nm.It was found an improvement of factor five could be gained photon yield using UTA rather than emission.The results are atomic structure calculations imply significant gain efficiency should tin, which comes similar UTA, as EUVL source material.