Reliable and compact extreme ultraviolet (EUV) laboratory sources are strongly required for in-house characterization
of optical components and for the precise calibration of EUV diagnostic instruments. The EUV tube, based on the
transfer of advanced microfocus x-ray tube technology into the EUV spectral range around 13.5 nm, is an important
tool for these applications. Great benefits of this source are a compact and flexible design, debris-free operation, and
high temporal and spatial long-term stability. Detailed characteristics of the source performance are reported and
different examples for at-wavelength metrology are presented.
Extreme ultraviolet lithography (EUVL) is the leading technology for patterning at the 32 nm technology node and be-yond. EUVL light at 13.5 nm is used to print circuits. This light is produced by heating fuel (Xe, Sn) in EUV sources to a very high temperature by using either magnetic compression or laser irradiation. Today EUV source power remains the number one concern for implementation of EUVL in high volume manufacturing. Over the last few years, much pro-gress has been made in EUV source performance and availability. Today, alpha level high power (~10 W) EUV sources have been integrated in alpha level EUVL scanners. Medium and low power EUV sources are used for in-house metrol-ogy and performance studies on EUV mask blanks, EUV masks, photoresists, and optical elements. These compact dis-charge sources with medium power in the range of 10-100 mW/sr/2% bandwidth and low power EUV tubes are being used by various R&D labs for development of mask, optics, and resists. Previously, development of EUVL was mostly located at beamlines; today, these low power EUV sources are instrumental in allowing in-house R&D projects. In this paper, the latest status of high power EUV sources, low and medium power metrology sources, and some of their appli-cations are described.
Reliable and compact extreme ultraviolet (EUV) laboratory sources are strongly required for in-house characterization
of optical components and for the precise calibration of EUV diagnostic instruments. The EUV tube, based on the
transfer of advanced microfocus x-ray tube technology into the EUV spectral range around 13.5 nm, is an important
tool for these applications. Great benefits of this source are a compact and flexible design, debris-free operation, and
high temporal and spatial long-term stability. Detailed characteristics of the source performance are reported and
different examples for at-wavelength metrology are presented.
For the precise characterization, optimization, and quality control of multilayer mirrors, masks, and other optical components for extreme ultraviolet (EUV) lithography, compact and flexible metrology tools are strongly required. At present, the characterization of EUV optics is carried out at synchrotron facilities. Usually this is a very expensive and time-consuming procedure. Therefore, compact, cheap, and easy-to-operate tools and systems are needed for a fast and reliable in-house at-wavelength reflectivity control.
In this presentation we will provide an update on our commercial compact EUV source for in-house at-wavelength metrology. This source, called EUV tube, is based on electron-induced characteristic emission from solid targets. The EUV tube is debris-free, has excellent long-term temporal and spatial stability, and very low running costs. All source parameters are computer-controlled and the source size can be adjusted down to 10 μm. Recent improvements on EUV power scaling will be presented. Different applications in the field of at-wavelength metrology will be highlighted. New results on EUV reflectometry of multilayer mirrors and grazing incidence optics will be demonstrated and compared with measurements obtained at synchrotron and plasma-based facilities.
In EUV lithography, extreme ultraviolet radiation of 13.5 nm wavelength is used to print feature with resolutions consis-tent with the requirements of the 45 nm technology node or below. EUV is produced by heating xenon, tin, or other ele-ments to a plasma state, using either magnetic compression or laser irradiation. The key concerns-identified at the third EUV-Symposium-are the ability to supply defect-free masks and to increase source component lifetimes to meet the wafer throughput requirements for high volume manufacturing. Source availability and performance, however, made steady progress within the last years on two lines of actions: High power sources for high volume production and medium and low power sources for allowing in-house metrology and performance studies on EUV-mask-blanks, EUV-Masks, photoresists and optical elements.
For "volume production sources" 50 W of collected EUV powers are already available by various suppliers. Compact discharge sources of medium power in the range of 10-100 mW / sr / 2% bandwidth and low power EUV-tubes of low-est cost of ownership and superior stability are ideal for peripheral metrology on components for EUV-Lithography. These low power sources supplement beamlines at storage rings by transferring EUV-applications to individual R&D labs. Proceeding integration of those EUV sources into tools for technology development like open frame and micro-exposers, and in tools for actinic metrology is the best proof of the progress. As of today, the first EUV sources and measurement equipment are available to be used for EUV system, mask, optics and component as well as lithography process development. With the commercial availability of EUV-plasma sources other applications using short wave-length, XUV-radiation will be feasible in a laboratory environment. Some examples of XUV applications are discussed.
Compact extreme ultraviolet (EUV) laboratory sources are strongly required for the fast on-site characterization of optical components and for the precise calibration of EUV diagnostic instruments. The "EUV tube" promises to become an important tool for these applications. This source is based on the transfer of advanced microfocus x-ray tube technology into the EUV spectral range. This allows the realization of a flexible, debris-free, and long-term stable EUV source. Silicon targets are used to generate radiation at 13.5 nm. Detailed characteristics of the source performance are reported and different examples for off-synchrotron at-wavelength metrology are presented.
Two applications of an electron-based EUV-tube are presented: the set up of a grazing incidence EUV reflectometer with high reproducibility and accuracy, and our works towards the realization and application of a Schwarzschild objective for EUV imaging. Both applications benefit form the use of the table-top EUV-source, which is debris-free, long-term stable, and compact.
Recently, an electron-based ultrashort hard-x-ray source has been developed at the Laser Zentrum Hannover e.V. In this source x-ray pulses are produced by combining femtosecond laser technology with a specially designed x-ray diode. At first, ultrashort electron pulses are generated by photoemission from a photocathode. Then, these electron pulses are accelerated over a short distance towards a high-Z anode. Hard-x-rays are produced via Bremsstrahlung and characteristic line emission. Now detailed measurements of the hard-x-ray pulse duration have been performed using an advanced streak camera. The streak camera has a sub-picosecond time resolution in the keV range. With this camera hard-x-ray pulse durations of less than 5 ps were observed for electron pulse charges of the order of several pC. In this contribution we present our results on the x-ray pulse duration measurements and their dependence on different experimental parameters. A comparison with theoretical simulations is given.
Recently, an electron-based ultrashort hard-x-ray source has been developed at the Laser Zentrum Hannover e.V. In this source x-ray pulses are produced by combining femtosecond laser technology with a specially designed x-ray diode. At first, ultrashort electron pulses are generated by photoemission from a photocathode. Then, these electron pulses are accelerated over a short distance towards a high-Z anode. Hard-x-rays are produced via Bremsstrahlung and characteristic line emission.
Now detailed measurements of the hard-x-ray pulse duration have been performed using an advanced streak camera. The streak camera has a sub-picosecond time resolution in the keV range. With this camera hard-x-ray pulse durations of less than 10 ps were observed for electron pulse charges of the order of several pC.
In this contribution we present our results on the x-ray pulse duration measurements and their dependence on different experimental parameters. A comparison with theoretical simulations is given.
A compact electron-based microfocus EUV/soft-x-ray source for applications in metrology and microscopy is developed. The source concept is based on the transfer of advanced microfocus x-ray tube technology into the EUV/soft-x-ray spectral range. This allows the realization of a flexible, debris-free, and long-term stable source. Detailed characteristics of the source performance are reported and different applications of the soft-x-ray tube in the field of at-wavelength metrology are presented.
A compact electron-based extreme ultraviolet (EUV) source for advanced at-wavelength mirror metrology is developed. The source concept is based on the transfer of advanced microfocus x-ray tube technology into the EUV spectral range. This allows the realization of a flexible, debris-free, and long-term stable EUV source. In the EUV tube, silicon targets are used to generate radiation at 13.5 nm. Detailed characteristics of the source performance are reported and different applications of the EUV tube in the field of at-wavelength mirror metrology are presented.
A compact electron-based extreme ultraviolet (EUV) source for at-wavelength metrology is developed. The source concept is based on the transfer of advanced microfocus x-ray tube technology into the EUV spectral range. This allows the realization of a flexible, debris-free, and long-term stable EUV source. In the EUV tube, silicon targets are used to generate radiation at 13.5 nm. Detailed characteristics of the source performance are reported and different applications of the EUV tube in the field of at-wavelength metrology are presented.
A commercial extreme ultraviolet (EUV) source for at-wavelength metrology is developed. The source concept is based
on the transfer of advanced microfocus x-ray tube technology into the EUV spectral range. This concept allows the
realization of a compact, debris-free, and long-term stable EUV source. In the EUV tube, silicon targets are used to
generate radiation at 13.5 nm. Detailed characteristics of the source performance are reported and different applications
of the source in the field of at-wavelength metrology are presented.
The development of suitable radiation sources for extreme ultraviolet lithography (EUVL) is a major challenge. For the optimization of these sources and for the determination of the parameters needed for the system design and the system integration these sources have to be characterized in terms of the absolute in-band power, the spectral distribution in the EUV spectral region and the out-of-band spectral regions, the spatial distribution of the emitting volume and the angular distribution of the emission. For improving the lifetime of such sources, generally accepted as one key risk with EUVL, another task, the debris emitted from sources under development has to be investigated. Therefore, JENOPTIK Mikrotechnik GmbH is co-operating with the Laser Laboratorium Goettingen, the Physikalisch-Technische Bundesanstalt (PTB) and the AIXUV GmbH in developing ready-for-use metrology tools for EUVL source characterization and optimization. The set of the tools employed for EUV-source characterization is presented in detail as well as concepts for calibration and measurement procedures.
A review of our progress in the realization of an ultrashort-pulse laser-driven hard-x-ray source based on the combination of a femtosecond laser system with an x-ray diode is given. New results on the development of electron-based compact EUV sources for "at-wavelength" metrology are presented. Detailed investigations of spectral, spatial, and temporal characteristics of both sources are performed and possible applications are discussed.
A compact extreme ultraviolet (EUV) source for metrology is developed. This source is based on an extension of conventional x-ray tube technology into the EUV spectral range. As in an ordinary x-ray tube, electrons are generated by a filament, accelerated in a high-voltage electric field toward an anode, and focused onto a solid target. In this "EUV tube" silicon targets are used to generate radiation at 13.5 nm. Absolute conversion efficiencies from electrons into EUV photons are measured. Illustrations of spectral and spatial properties are given and investigations of the long-term stability of the EUV emission are performed. Possibilities for a power scaling into the milliwatt range are discussed.
Recent progress in the development of a compact, high-repetition rate, ultrashort-pulse laser-driven hard-x-ray source based on the combination of a femtosecond laser system with an x-ray diode is reported. The x-ray source is characterized in terms of spectral and spatial properties. Hard-x-ray fluxes exceeding 2x1010 photons/s (emitted in 4π sr) are realized at a repetition rate of 250 kHz. A comparison with available laser-plasma hard-x-ray sources is presented. Numerical modeling is performed which proves that picosecond and sub-picosecond hard-x-ray pulses can be produced with this source. Further prospects and possible applications of the femtosecond laser-driven x-ray diode are outlined.
Generation of extreme ultraviolet (EUV) radiation from solid targets is studied and a compact EUV source for small-scale lithographic applications and EUV metrology is development. This source is based on a transfer of conventional x-ray tube technology into the EUV spectral range. As in an ordinary x-ray tube, electrons are generated by a tungesten filament and accelerated in a high-voltage electric field towards a solid target. In the demonstrated "EUV tube" beryllium and silicon targets are used to generate radiation at 11.4 nm and 13.5 nm, respectively. The absolute converstion efficiencies into EUV photons are measured. At 13.5 nm an EUV power of 34μW or 2×1012 photon/s (in 2% bandwidth and a solid angle of 2π sr) is demonstrated. Prospects for a further power scaling of the EUV source are discussed.
Generation of extreme ultraviolet (EUV) radiation from solid targets is studied and a compact EUV source for small-scale lithographic applications and EUV metrology is developed. This source is based on a transfer of conventional x-ray tube technology into the EUV spectral range. As in an ordinary x-ray tube, electrons are generated by a tungsten filament and accelerated in a high-voltage electric field toward a solid target. In the demonstrated "EUV tube" beryllium and silicon targets are used to generate radiation at 11.4 and 13.5 nm, respectively. The absolute conversion efficiencies into EUV photons at 13.5 nm are measured. Prospects for a further power scaling of the EUV source are discussed.
A compact, high-repetition rate, ultrashort-pulse laser-driven hard-x-ray source based on the combination of a femtosecond laser system with an x-ray diode is demonstrated. A comparison with available laser-plasma hard-x-ray sources is presented. Hard-x-ray fluxes exceeding 1010 photons/s (emitted in 4π) are realized at a repetition rate of 250 kHz. Numerical modeling is performed which proves that picosecond and sub-picosecond hard-x-ray pulses can be produced with this source.
A compact indirect laser-driven ultrashort electron and hard-x-ray source based on the combination of a high-repetition rate femtosecond laser system with a conventional x-ray tube is demonstrated. The influence of laser parameters on thermionic electron emission and on the hard-x-ray generation efficiency is studied. This source has an outstanding performance in terms of average power, simplicity, handling, and applicability as compared to the sources based on high-power laser-produced plasmas.
Collisional X-UV lasers are now currently produced world-wide. The LSAI team has developed at LULI an efficient, high brightness laser at 21.2 nm, using neonlike zinc. Beside the effort aimed at improvement of efficiency of the neonlike X-UV lasers, the LSAI recent activity has covered scaling the collisional scheme down to shorter wavelengths, as well as development of applications. In this paper we present results of applications of the 21.2 nm laser in atomic physics, solid state physics, and X-UV interferometry of surfaces. The emphasized message is that the characteristics of the existing X-UV lasers render possible applications in many research areas nowadays.
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