The development of suitable radiation sources is a major challenge for extreme ultraviolet lithography (EUVL). 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-band spectral regions, the spatial distribution of the emitting volume and the angular distribution of the emission. Also the source debris has to be investigated. Therefore, JENOPTIK Mikrotechnik GmbH is co-operating with the Laser Laboratorium Göttingen, 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 of for calibration and measurement procedures.

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Compact, flexible laboratory sources offer advanced flexibility in developing components for EUV-lithography by supplementing beamlines at storage rings. Hence, they are the basis for transferring EUV-metrology and technology to individual, industrial and university R&D labs. Laboratory sources have features similar to the sources planned for EUVL production on one hand and offer high flexibility like storage ring beamlines on the other hand. Discharge based EUV sources offer some flexibility, which allow for tuning of the spectral and spatial characteristics of their emission. Depending on the system complexity sources can be supplied in various forms ranging from low budget semi-manual systems over OEM components to fully automatic stand-alone sources. As power scaling has been demonstrated by just adding higher power generators and cooling, these sources can be matched to various levels of flux requirements. AIXUV's discharge based EUV-sources have been used as beaml ine supplement for tasks closely connected with the development of EUV-Lithography. Examples are: development of tools for EUV source characterization (prototype testing, qualification and calibration), "in-band-EUV" open frame resist exposure, reflectometry of EUV mask blanks and EUV mirrors and for basic research using XUV radiation as thin film analytics and EUV microscopy

In EUV lithography, extreme ultraviolet radiation of 13.5 nm wavelength is used to print feature with resolutions consistent with the requirements of the 45 nm technology node or below. EUV is produced by heating xenon, tin, or other elements 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 lowest 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 microexposers, 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 wavelength, XUV-radiation will be feasible in a laboratory environment. Some examples of XUV applications are discussed.

A prototype of a reflectometer for masks and mask blanks has been set-up in autumn 2003 for in-house quality check of EUV mask blanks at Schott Lithotec. The target specifications are those under discussion as SEMI standard for EUV mask blank reflectometry. Additionally, the identified demands for semiconductor capital investment for future actinic EUV metrology, high throughputs and small measuring spots, were taken into account for the tool development. Effective use of the emission from a laboratory discharge source is achieved by using polychromatic reflectometry, which has been shown to deliver results about a factor of 100 faster with the same source power and needs less mechanical overhead than a monochromatic reflectometer. The hardware concept, first results and discussion of a test of the performance with respect to resolution, uncertainty and reproducibility will be represented. Jointly with the Physikalisch-Technische Bundesanstalt's laboratory for radiometr y at BESSY II the traceability to storage ring metrology, the calibration and the validation of the concepts will be assessed