As EUV lithography is on its way into production stage, studies of optics contamination and cleaning under realistic conditions become more and more important. Due to this fact an Exposure Test Stand (ETS) has been constructed at XTREME technologies GmbH in collaboration with Fraunhofer IOF and with financial support of Intel Corporation. This test stand is equipped with a pulsed DPP source and allows for the simultaneous exposure of several samples. In the standard set-up four samples with an exposed area larger than 35 mm(2) per sample can be exposed at a homogeneous intensity of 0.25 mW/mm(2). A recent update of the ETS allows for simultaneous exposures of two samples with intensities up to 1.0 mW/mm(2). The first application of this alternative set-up was a comparative study of carbon contamination rates induced by EUV radiation from the pulsed source with contamination rates induced by quasi-continuous synchrotron radiation. A modified gas-inlet system allows for the introduction of a second gas to the exposure chamber. This possibility was applied to investigate the efficiency of EUV-induced cleaning with different gas mixtures. In particular the enhancement of EUV-induced cleaning by addition of a second gas to the cleaning gas was studied.

Comparative lifetime studies of Mo/Si multilayer mirrors have been conducted at the Exposure Test Stand (ETS) using a pulsed Xe-discharge EUV source at XTREME Technologies GmbH (Göttingen, Germany). Due to the large, homogeneous exposed sample area a multi-technique study of EUV induced carbon contamination and cleaning can be conducted using standard surface science techniques. EUV-reflectometry, X-ray photoelectron spectroscopy (XPS), small-angle X-ray reflectometry (SAXR), and Out-of-band (OOB) reflectometry (200 - 1000 nm) were applied to investigate exposed samples and study EUV-induced changes of the surface composition. With this approach the influence of EUV-dose, cleaning-gas pressure and composition, and capping-layer material of the Mo/Si multilayer samples on the degradation and cleaning mechanism can be studied.

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.

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.

Summary form only given. An alternative way to generate ultrashort hard-x-rays is to use low-intensity femtosecond laser pulses in combination with a specially designed "x-ray tube". The femtosecond laser pulses induce photoemission of electrons from a photocathode. The electron bunch is then accelerated towards a high-Z target material by applying an external high-voltage electric field. Hard-x-rays are produced by bremsstrahlung of accelerated electrons and characteristic line emission. In contrast to the existing laser-plasma x-ray sources which require high-power laser systems, for the realization of this novel x-ray source, low-energy, compact, high-repetition rate, commercially available femtosecond lasers can be used. In this presentation we report on our progress in the development and investigation of a femtosecond laser-driven x-ray tube. We demonstrate the influence of relevant parameters (e.g. laser fluence, wavelength, accelerating voltage) on the electron and hard-x-ray generation efficiency using different photocathode and x-ray target materials. The laser-driven hard-x-ray source is characterized in terms of brilliance, spectral properties, and pulse duration. The latter is performed using an ultrafast x-ray streak camera in combination with a laser-triggered accumulation system.

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.

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.