Source Of Extreme Ultraviolet Radiation Research Articles

Prospects of extreme ultraviolet radiation sources based on microwave discharge for high-resolution lithography

In this paper, inspired by the success of recent experiments, we discuss a new possible type of sources of extreme ultraviolet radiation for the semiconductor industry, based on the radiating plasma with multiply charged ions supported in a mirror magnetic trap by high-power microwaves. We propose a simple theory that describes the main features of such source, perform modeling for a wide range of plasma parameters and magnetic configurations, compare the results to the existing experimental data, and study the prospects of the new scheme in present technological circumstances.

Droplet-based, high-brightness extreme ultraviolet laser plasma source for metrology

We report on the development of a high brightness source of extreme ultraviolet radiation (EUV) with a working wavelength of 13.5 nm. The source is based on a laser-produced plasma driven by pulsed radiation of a Nd:YAG laser system. Liquid droplets of Sn-In eutectic alloy were used as the source fuel. The droplets were created by a droplet generator operating in the jet break-up regime. The EUV emission properties of the plasma, including the emission spectrum, time profile, and conversion efficiency of laser radiation into useful 13.5 nm photons, have been characterized. Using the shadowgraphy technique, we demonstrated the production of corpuscular debris by the plasma source and the influence of the plasma on the neighboring droplet targets. The high-frequency laser operation was simulated by usage of the dual pulse regime. Based on the experimental results, we discuss the physical phenomena that could affect the source operation at high repetition rates. Finally, we estimate that an average source br...

Investigations on the emission in the extreme ultraviolet of a pseudospark based discharge light source

A new concept of a discharge based extreme ultraviolet radiation source is presented. This concept is based on an electrode system that consists of two consecutive pseudospark discharge stages. The first stage is used to create a pinch plasma as emitter in the extreme ultraviolet and soft X-ray range and the second stage is used as a high current switch between the storage capacity and the first stage. First results on the emission characteristics for the working gases nitrogen, krypton, and xenon, with focus on the emission at 2.88 nm, 6–7 nm, and around 13.5 nm, respectively, are disclosed under the aspect of the access to a larger discharge parameter range. It is shown that this increased range opens a path to a higher spectral peak brightness.

Discriminating between the Role of Phase Matching and that of the Single-Atom Response in Resonance Plasma-Plume High-Order Harmonic Generation.

Resonance enhancement of high-order harmonic generation has recently been found in the interaction of intense ultrashort laser pulses with laser ablated plasma plumes. It is a promising route towards the production of an intense and coherent extreme ultraviolet radiation source. However, the mechanism of this resonance enhancement is still not clear. There are two possible explanations; one relies on a better recombination cross section through an autoionization state in the single-atom response. The other relies on improved phase matching conditions around the resonance. Here, we try to discriminate between these two conjectures by measuring coherence lengths of the harmonics, both on resonance and off resonance. Our findings support the single-atom response hypothesis.

A point-like source of extreme ultraviolet radiation based on a discharge in a non-uniform gas flow, sustained by powerful gyrotron radiation of terahertz frequency band

The possibility and prospects of extreme ultraviolet (UV) point-like source development are discussed in the present paper. The UV source is based on the discharge sustained by powerful gyrotron radiation of terahertz (THz) frequency band in non-uniform gas flow injected into vacuum volume through a nozzle with diameter less than 1 mm. Recent developments of THz-band gyrotrons with appropriate power level made such discharges possible. First experimental results on a point-like plasma creation by 100 kW radiation of 0.67 THz gyrotron are presented. The possibility of discharge localization within the area less than 1 mm is demonstrated. The discharge emission within the wavelength range from 112 nm to 650 nm was studied. The measured power of light emission in the range of 112–180 nm was measured to be up to 10 kW.

Cancer cell classification with coherent diffraction imaging using an extreme ultraviolet radiation source.

In cancer treatment, it is highly desirable to classify single cancer cells in real time. The standard method is polymerase chain reaction requiring a substantial amount of resources and time. Here, we present an innovative approach for rapidly classifying different cell types: we measure the diffraction pattern of a single cell illuminated with coherent extreme ultraviolet (XUV) laser-generated radiation. These patterns allow distinguishing different breast cancer cell types in a subsequent step. Moreover, the morphology of the object can be retrieved from the diffraction pattern with submicron resolution. In a proof-of-principle experiment, we prepared single MCF7 and SKBR3 breast cancer cells on gold-coated silica slides. The output of a laser-driven XUV light source is focused onto a single unstained and unlabeled cancer cell. With the resulting diffraction pattern, we could clearly identify the different cell types. With an improved setup, it will not only be feasible to classify circulating tumor cells with a high throughput, but also to identify smaller objects such as bacteria or even viruses.

Conceptual designs of a laser plasma accelerator-based EUV-FEL and an all-optical Gamma-beam source

Abstract Recently, intense research into laser plasma accelerators has achieved great progress in the production of high-energy, high-quality electron beams with GeV-level energies in a cm-scale plasma. These electron beams open the door for broad applications in fundamental, medical, and industrial sciences. Here we present conceptual designs of an extreme ultraviolet radiation source for next-generation lithography and a laser Compton Gamma-beam source for nuclear physics research on a table-top scale.

Spectral characterization of laser-driven solid-based high harmonics in the coherent wake emission regime

Laser-produced surface high-harmonic generation is an attractive source of extreme ultraviolet radiation due to its coherent properties and high peak power. By operating at subrelativistic laser intensities in the coherent wake emission regime, the harmonic spectrum was experimentally studied versus laser properties. At higher laser intensities (>10(17) W/cm(2)) a higher spectral cutoff was observed, with accompanying blueshifting and spectral broadening of the individual orders. A model based on an expanding critical surface provides qualitative agreement with the observations.

A laser plasma source of EUV radiation for projection nanolithography

A laboratory laser plasma source of extreme ultraviolet radiation optimized for use on a nanolithography test bench at a wavelength of 13.5 nm is described. The key characteristics of the source are presented. When operating with a molybdenum target, the measured ratio of laser pulse energy conversion into radiation with a central wavelength of 13.5 nm into the half-space and in the 2% spectral band is 0.03%.

Errata: RZLINE code modeling of distributed tin targets for laser-produced plasma sources of extreme ultraviolet radiation

Errata: RZLINE code modeling of distributed tin targets for laser-produced plasma sources of extreme ultraviolet radiation

RZLINE code modeling of distributed tin targets for laser-produced plasma sources of extreme ultraviolet radiation

An integrated model is developed to describe the hydrodynamics, atomic, and radiation processes that take place in extreme ultraviolet (EUV) radiation sources based on a laser-produced plasma with a distributed tin target. The modeling was performed using the return-to-zero line code-a numerical code for the simulation of EUV emission by hot dense plasmas. The purpose of the simulation is to evaluate the spectral characteristics of the radiation source, conversion efficiency, source size, evaporation rate of the target, energetic, and space distribution of debris (nanoparticles, neutrals, and ions). The advantages of a distributed target in comparison with a single droplet target are also discussed.

System for illumination of an EUV-nanolithograph mask

The system for illuminating a mask of the nanolithograph for EUV lithography at the 13.5 nm wavelength is considered. The basic elements of the system are a source of extreme ultraviolet radiation, a spherical mirror-collector, and a compound mirror (homogenizer) that consists of 25 minimirrors and provides uniform exposure of the required area of the mask. Numerical computations of minimirror parameters are given in comparison to experiments, and reflection factors of minimirrors in the vicinity of λ = 13.5 nm are presented.

An extreme ultraviolet radiation source based on plasma heated by millimeter range radiation

An extreme ultraviolet (EUV) radiation source based on a low-pressure discharge sustained in a magnetic trap by high-power electromagnetic radiation at a frequency of 75 GHz is discussed. The experimental radiation power in the wavelength range of 13.5 nm ±1% was as high as 50 W. The conversion of microwave radiation into EUV radiation was about 1%.

Ground-state configurations and unresolved transition arrays in extreme ultraviolet spectra of lanthanide ions

Theoretical ground-state configurations of lanthanide ions calculated with the Cowan suite of codes are presented. Theoretical $4d$-$4f$ and $4p$-$4d$ spectra of Pd-like to Rb-like lanthanide ions calculated using the relativistic flexible atomic code are also shown. The effects of configuration interaction are investigated, and the results compare favorably with experiments in which, for increasing nuclear charge, strong emission peaks are observed to move toward shorter wavelength. The application of these strong emitters as extreme ultraviolet radiation sources, a topic of emerging interest, is discussed.

Nonclassical hydrodynamic behavior of Sn plasma irradiated with a long duration CO2 laser pulse

It was found that the electron density scale length of Sn plasma irradiated with a long duration CO2 laser pulse is much shorter than that predicted by the classical isothermal model. The experimentally observed small dominant region of in-band (2% bandwidth) 13.5-nm extreme ultraviolet (EUV) emission coincides with this constrained hydrodynamic behavior. The lower hydrodynamic efficiency may come from the strongly inhibited ablation mass and makes a CO2-laser-produced Sn plasma suitable as an EUV radiation source.

Tunable Enhancement of High Harmonic Emission from Laser Solid Interactions

Coherent wake emission is a unique source of extreme ultraviolet radiation and has been recently shown to provide the basis for intense attosecond light. Here we present a novel scheme, supported by particle-in-cell simulations, demonstrating that enhancement and spectral control of the coherent wake emission signal can be achieved by modifying the interaction plasma density ramp. Significant tunable enhancement of harmonic emission is verified experimentally, with factors of >50 in relative signal increase achieved in a narrow band of harmonics at the cutoff frequency.

Operation of a free-electron laser from the extreme ultraviolet to the water window

We report results on the performance of a free-electron laser operating at a wavelength of 13.7 nm where unprecedented peak and average powers for a coherent extreme-ultraviolet radiation source have been measured. In the saturation regime, the peak energy approached 170 µJ for individual pulses, and the average energy per pulse reached 70 µJ. The pulse duration was in the region of 10 fs, and peak powers of 10 GW were achieved. At a pulse repetition frequency of 700 pulses per second, the average extreme-ultraviolet power reached 20 mW. The output beam also contained a significant contribution from odd harmonics of approximately 0.6% and 0.03% for the 3rd (4.6 nm) and the 5th (2.75 nm) harmonics, respectively. At 2.75 nm the 5th harmonic of the radiation reaches deep into the water window, a wavelength range that is crucially important for the investigation of biological samples.

Extreme ultraviolet source radiated from pinch plasma for semiconductor manufacturing

Plasma extreme ultraviolet (EUV) source is regarded as the most promising source of EUV radiation as intensive research is underway over the world. A top priority issue for implementing EUV lithography is to upgrade the EUV power extensively. In the development of Z-pinch plasma EUV source, xenon gas is used for the target. The Z-pinch plasma was driven by pulsed current with an amplitude of 30 kA and pulse duration of 100 ns. Pinhole imaging, EUV spectrograph and an in-band EUV energy monitor were used to characterise the EUV emission from the Z-pinch discharge plasma. In order to improve the conversion efficiency (CE) from input electric energy to EUV radiation, a solid tin rod was also used as target material. The experimental analyses have demonstrated that the CE was as high as 1.5%.

A Trend in Pulse-Powered Plasma Radiation Source

Recent progress of semiconductor power devices has shifted our interests on pulsed-power energy driver from a huge energetic system to a high-average-power compact generator. Intense extreme ultraviolet radiation sources have been developed using those devices. It is considered that they can be the light sources for microscopy and the next generation microlithography. A trend and a prospect for the pulse powered radiation sources are briefly described.

A novel-type tunable and narrowband extreme ultraviolet radiation source based on high-harmonic conversion of picosecond laser pulses

At the Laser Centre Vrije Universiteit a table-top size, tunable and narrowband laser-based source of extreme ultraviolet radiation was developed using high-harmonic generation of powerful laser pulses of 300 ps duration and Fourier-transform limited bandwidth. The generated radiation has unprecedented spectral purity of λ / Δ λ > 2.5 × 1 0 5 at wavelengths covering the entire tunability range of 40–100 nm. The process of high-order harmonic generation was investigated in different gases (Ar, Kr, Xe, N 2) uncovering resonance phenomena for the conversion efficiency of specific harmonic orders.