Pulsed Laser Deposition (PLD) is used for the preparation of Ni/C, W/C, and Mo/Si multilayers having X-ray optical quality. For the synthesis of layer stacks involving a uniform or a graded thickness distribution across 4"-wafers the conventional thin film deposition equipment of PLD has been modified. This modification provides a precise spatial control of the plasma plume orientation in the deposition chamber. With this arrangement the emission characteristic of the plasma source can be computer controlled and the desired coating profile can be tailored across an extended substrate via a stepper-motor-driven target manipulator. Thus film thickness uniformity (δts < 2%) is obtained on substrates up to 4" diameter even for smaller target-substrate distances. For laterally graded Ni and C individual layers linear thickness gradients of dts/dx = 3.2 × 10−8 were confirmed over the total substrate length by spectroscopic ellipsometry. The parameters deduced from single layer deposition were applied for the synthesis of laterally graded Ni/C multilayers. A mean value of the gradient of the stack period thickness dt/dx = 6.2 × 10−8 confirmed by X-ray reflectometry (nominal value: dt0 /dx = 6.4×10−8 ) characterizes precision and reproducibility of the coating process.

Mo/Si multilayer systems with boron carbide (B4C) diffusion barrier layers were deposited on sapphire and silicon substrates by DC magnetron sputtering. Samples were subsequently annealed in vacuum at temperatures between 100 and 800 °C for duration of between 20 min and 30 h. Thermally stimulated solid state reactions have been characterized by X-ray analysis methods. Mo/Si multilayers without barrier layers are stable up to 100 °C. Interdiffusion was observed to start by 150 °C. It was found that B4C diffusion barrier layers with thicknesses between 0.3 and 1.0 nm, depending on the stack sequence, give rise to an increase of the thermal stability up to 400 °C. The impact of thermal treatments, at various temperatures and annealing times, on thickness and composition of the interdiffusion layers was investigated by X-ray reflectometry, wide angle X-ray scattering, cross-sectional high resolution transmission electron microscopy and fluorescence extended X-ray absorption fine structure measurements in combination with excitation of X-ray standing waves. The last method was used to investigate the short-range order of Mo/Si multilayers depth-resolved.

AbstractFür die EUV‐Lithographie, die als aussichtsreichstes Verfahren für die Herstellung von Halbleiterstrukturen unterhalb von 50 nm gilt, kommen reflektierende Multischichten als optische Elemente zum Einsatz. Diese müssen eine möglichst hohe Reflektivität aufweisen, da diese die Effizienz des Verfahrens und damit den Durchsatz einer zukünftigen Chip‐Fabrik maßgeblich bestimmt.In dieser Arbeit werden Untersuchungen zur Grenzflächenbeschaffenheit von Mo/Si Multischichten, die mittels Magnetron Sputter Deposition hergestellt wurden, vorgestellt. Ausgehend vom zweikomponentigen Mo/Si‐System, bei dem vorrangig der Einfluss der Abscheidebedingungen auf die Grenzflächenrauhigkeit betrachtet wird, gelang es, durch den Einbau von dünnsten Barriereschichten auch die Grenzflächeninterdiffusion zu reduzieren.Im reinen Mo/Si System ist vor allem ein niedriger Ar‐Sputtergasdruck wichtig, um glatte Grenzflächen zu erzeugen. Die Verringerung der Interdiffusion der Mo‐ und Si‐Atome kann durch den Einbau von C‐ und B4C‐Barriereschichten geeigneter Dicke erreicht werden.Als Ergebnis der Untersuchungen wurden Mo/Si Multischichten mit momentan den weltweit höchsten EUV‐Reflektivitäten präpariert: REUV= 70.1 % (λ = 13.3 nm, α = 1.5°), REUV= 71.4 % (λ = 12.5 nm, α = 22.5°).

The quality assurance for production of optical components for EUV lithography strongly requires at-wavelength metrology. Presently, at-wavelength characterizations of mirrors and masks are done using the synchrotron radiation of electron storage rings, e.g. BESSY II. For the production process of EUV optics, however, the immediate access to metrology tools is necessary and availability of laboratory devices is mandatory. Within the last years a stand alone laboratory EUV reflectometer for large samples has been developed It consists of a laser produced plasma (LLP) radiation source, a monochromator and a large goniometer systme. The manipulation system of the reflectometer can handle samples with diameters of up to 500 mm, thicknesses of up to 200 mm and weights of up to 30 kg. The wavelength can be varied from 10 nm to 16 nm. The spot size on the sample surface is about 2mm. The angle of incidence can be varied from 3° to 60°. In this paper, we describe the laboratory reflectometer in detail and discuss the achieved performance. First measurements of 4 inch mirrors are presented and discussed in comparison to the results obtained at the PTB soft x-ray radiometry beamline at BESSY II.

This chapter contains sections titled: Interconnects for Microelectronics Introduction Metallization Layers Materials Science of Metallic Interconnects Function of Barrier and Nucleation Layers and Materials Selection Metallization Structures in Acoustoelectronics Introduction Fundamentals of Surface Acoustic Waves Interdigital Transducers (IDTs) Reflector Gratings Waveguides, Energy Trapping Multistrip Couplers Silicide Layers for Electronics Introduction The Basic Chemical and Physical Properties Preparation of Silicides Silicides with Metallic Conductivity Semiconducting Silicides Heterogeneously Disordered Silicide Films Complex Layered Systems for Magnetoelectronics Introduction Magnetism: A Primer Magnetic Coupling Phenomena Electric Transport in Layered Magnetic Systems Functional Thin Film Systems Multilayer and Single-Surface Reflectors for X-Ray Optics Introduction Refraction and Reflection at Single Boundaries BRAGG Reflection at 1D Lattice Systems Multilayer Preparation References

Mo/Si multilayers with and without diffusion barrier layers have been prepared by dc magnetron sputter deposition. The introduction of C and B4C barrier layers reduces the formation of the well-known MoSix intermixing zones on the interfaces and improves the optical contrast between absorber and spacer layers. Using these barriers the EUV reflectivity was increased from 68.7% (λ=13.46nm, α=1.5°) for pure Mo/Si multilayers to 69.9% (λ=13.5nm, α=1.5°) for Mo/B4C/Si/C multilayers. The microstructure of the layers has been investigated by HRTEM, X-ray diffractometry, Cu-Kα-and EUV-reflectometry. The introduction of thin C and B4C barrier layers (d=0.2-0.5nm) on the Mo-on-Si interface shifts the amorphous-to-crystalline transition to Mo layer thicknesses >2nm and reduces the size of the Mo crystallites. In multilayers with period thicknesses between 6.5nm and 7.0nm the optimum Mo layer thickness is close to the transition thickness. Therefore small changes of the ratio =dMo/dperiod result in amorphous or crystalline Mo layers. In both cases EUV reflectivities >69% are observed.

Pulsed laser deposition (PLD) and magnetron sputter deposition have been used to prepare different types of Mo/Si multilayers for the EUV spectral range, First of all, the pure Mo/Si system without any additional components has been investigated. The different growth mechanisms of the layers induced by the alternative deposition methods are discussed and the resulting reflectivities and microstructures are compared. Various materials (e.g. C, B/sub 4/C, Ag, W) were tested as barrier layers at the Mo-Si interface. We have investigated their influence on reflectivity and morphology of the resulting multilayer structures.

Die Beschichtung von Bauteilinnenflächen gewinnt mit den zunehmenden Anforderungen an Haltbarkeit und Leistungsfähigkeit der technischen Systeme immer mehr an Bedeutung. Beispiele hierfür sind der Wärme- und Oxidationsschutz in Brennkammern und Abgassystemen sowie der Verschleißschutz in durch Reibung beanspruchten Bauteilen wie Dämpferrohren oder Gießkokillen. Die zur Verfügung stehenden Verfahren weisen jedoch häufig Nachteile bezüglich der Homogenität der Beschichtung auf oder sind nur auf bestimmte Bauteilgeometrien anwendbar. Nachfolgend wird ein lasergestütztes Verfahren zur Innenbeschichtung von Bauteilen beschrieben, welches die Beschichtung komplexer Geometrien mit Durchmessern bis hinab in den mm-Bereich erlaubt. Die Kopplung der beiden Teilverfahren der Puls Laser Deposition (PLD), Laserablation und Laserverdampfung, ermöglicht dabei die Herstellung maßgeschneiderter Schichtsysteme hinsichtlich Mikrostruktur und Schichtdickenverteilung. Die Funktionsweise des Verfahrens wird anhand der Synthese von Wärmedämmschichten für Raketenbrennkammern erläutert. As the requirements on technical systems are growing in terms of durability and efficiency, coating of the inner walls of highly charged parts becomes more and more important. Well known examples are the protection of combustion chambers or exhaust systems against heat and oxidation as well as wear protection of friction loaded parts like shock-absorber tubes or casting moulds. The methods available for internal coating are often limited in the inner diameter of the systems to be coated and it has proven to be very difficult to deposit films homogeneously over a wide range. We present a method for coating of complex internal geometries with diameters down to several millimeters. The combination of classic Pulsed Laser Deposition (PLD) and laser evaporation enables synthesis of tailored film systems in terms of microstructure and distribution of single layer thickness. An example for the application of this method is given by means of the preparation of thermal barrier coatings in rocket combustion chambers.

In the past, the successful application of PLD for X-ray multilayer synthesis has already been demonstrated for C-spacer systems. Recently, the method has also been tested for Mo/Si layer stacks. A UHV-coating machine has been used to prepare X-ray mirrors on 4 in. substrates. The ablation of both Mo and Si targets was carried out by Nd:YAG laser irradiation using the third harmonic (λ=355 nm) with a pulse energy Ep=275 mJ and a pulse width τ=4…6 ns. Multilayers of 10…50 periods have been synthesized. Soft X-ray measurements in the EUV-range at near normal incidence show reflectivities Rs of typically 60%. From HRTEM, a high stack regularity and minimum interface roughness can be deduced. In contrast to conventional technologies (coating by sputtering or e-beam evaporation) the formation of a MoSix-interface layer happens only when depositing Mo on Si. Extremely sharp interface transitions from one individual layer to the other are observed and the total period is represented by a three-layer system. From TEM results, a structure model for PLD-prepared Mo/Si-multilayers has been deduced. The optical parameters of the layers were adapted by reflectivity curve fitting, so that the results measured in the EUV-range can be explained. Using this model, predictions of the ratio of the number of atoms NSi/NMo for the total stack were made and are in good agreement with results of RBS measurements. The use of the multilayers as X-ray optics requires an excellent homogeneity of the layer thickness across the entire mirror. It can be shown that the PLD technique is able to realize film uniformities with a standard deviation of the period thickness of less than 0.5%. This was confirmed by Cu–Kα-reflectometry and by near normal incidence measurements in the EUV range on 4 in. samples.

In the past, the successful application of PLD for X-ray multilayer synthesis has already been demonstrated for C-spacer systems. Recently, the method has also been tested for Mo/Si layer stacks. A UHV-coating machine has been used to prepare X-ray mirrors on 4 in. substrates. The ablation of both Mo and Si targets was carried out by Nd:YAG laser irradiation using the third harmonic (λ=355 nm) with a pulse energy Ep=275 mJ and a pulse width τ=4…6 ns. Multilayers of 10…50 periods have been synthesized. Soft X-ray measurements in the EUV-range at near normal incidence show reflectivities Rs of typically 60%. From HRTEM, a high stack regularity and minimum interface roughness can be deduced. In contrast to conventional technologies (coating by sputtering or e-beam evaporation) the formation of a MoSix-interface layer happens only when depositing Mo on Si. Extremely sharp interface transitions from one individual layer to the other are observed and the total period is represented by a three-layer system. From TEM results, a structure model for PLD-prepared Mo/Si-multilayers has been deduced. The optical parameters of the layers were adapted by reflectivity curve fitting, so that the results measured in the EUV-range can be explained. Using this model, predictions of the ratio of the number of atoms NSi/NMo for the total stack were made and are in good agreement with results of RBS measurements. The use of the multilayers as X-ray optics requires an excellent homogeneity of the layer thickness across the entire mirror. It can be shown that the PLD technique is able to realize film uniformities with a standard deviation of the period thickness of less than 0.5%. This was confirmed by Cu–Kα-reflectometry and by near normal incidence measurements in the EUV range on 4 in. samples.

Vakuum in Forschung und PraxisVolume 13, Issue 4 p. 222-231 Article Nanometer-Multischichtsysteme für die Röntgenanalytik Multilayer systems for X-ray analysisi R. Dietsch, R. Dietsch Fraunhofer Institut Werkstoff- und Strahltechnik, Winterbergstraße28, D-01277 Dresden, http://www.iws.fhg.deSearch for more papers by this authorTh. Holz, Th. Holz Fraunhofer Institut Werkstoff- und Strahltechnik, Winterbergstraße28, D-01277 Dresden, http://www.iws.fhg.deSearch for more papers by this authorA. Leson, A. Leson Fraunhofer Institut Werkstoff- und Strahltechnik, Winterbergstraße28, D-01277 Dresden, http://www.iws.fhg.deSearch for more papers by this authorH. Mai, H. Mai Fraunhofer Institut Werkstoff- und Strahltechnik, Winterbergstraße28, D-01277 Dresden, http://www.iws.fhg.deSearch for more papers by this authorD. Bahr, D. Bahr BRUKER AXS GmbH, Östliche Rheinbrückenstraße 50, D-76187 KarlsruheSearch for more papers by this authorL. Brügemann, L. Brügemann BRUKER AXS GmbH, Östliche Rheinbrückenstraße 50, D-76187 KarlsruheSearch for more papers by this authorJ. Lange, J. Lange BRUKER AXS GmbH, Östliche Rheinbrückenstraße 50, D-76187 KarlsruheSearch for more papers by this authorA. Hoffmann, A. Hoffmann PINK GmbH Vakuumtechnik, Am Kessler 06, D-97877 WertheimSearch for more papers by this authorF. Pink, F. Pink PINK GmbH Vakuumtechnik, Am Kessler 06, D-97877 WertheimSearch for more papers by this author R. Dietsch, R. Dietsch Fraunhofer Institut Werkstoff- und Strahltechnik, Winterbergstraße28, D-01277 Dresden, http://www.iws.fhg.deSearch for more papers by this authorTh. Holz, Th. Holz Fraunhofer Institut Werkstoff- und Strahltechnik, Winterbergstraße28, D-01277 Dresden, http://www.iws.fhg.deSearch for more papers by this authorA. Leson, A. Leson Fraunhofer Institut Werkstoff- und Strahltechnik, Winterbergstraße28, D-01277 Dresden, http://www.iws.fhg.deSearch for more papers by this authorH. Mai, H. Mai Fraunhofer Institut Werkstoff- und Strahltechnik, Winterbergstraße28, D-01277 Dresden, http://www.iws.fhg.deSearch for more papers by this authorD. Bahr, D. Bahr BRUKER AXS GmbH, Östliche Rheinbrückenstraße 50, D-76187 KarlsruheSearch for more papers by this authorL. Brügemann, L. Brügemann BRUKER AXS GmbH, Östliche Rheinbrückenstraße 50, D-76187 KarlsruheSearch for more papers by this authorJ. Lange, J. Lange BRUKER AXS GmbH, Östliche Rheinbrückenstraße 50, D-76187 KarlsruheSearch for more papers by this authorA. Hoffmann, A. Hoffmann PINK GmbH Vakuumtechnik, Am Kessler 06, D-97877 WertheimSearch for more papers by this authorF. Pink, F. Pink PINK GmbH Vakuumtechnik, Am Kessler 06, D-97877 WertheimSearch for more papers by this author First published: 15 August 2001 https://doi.org/10.1002/1522-2454(200108)13:4<222::AID-VIPR222>3.0.CO;2-JCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Die Abscheidung von Nanometer-Multischichtsystemen auf technisch relevanten Substraten stellt extreme Anforderungen an die jeweilige Beschichtungstechnologie hinsichtlich Präzision, Reproduzierbarkeit und Langzeitstabilität. Speziell für den Einsatz dieser Multischichten als röntgenoptisches Bauelement müssen eine Variation der Einzelschichtdicken im Bereich unterhalb σD = 0,1nm in einem Schichtstapel mit mehr als 150 Einzelschichten und eine Reproduzierbarkeit der mittleren Periodendicke zwischen zwei Abscheidezyklen von Δd ≤ 0,1nm bei der Beschichtung von Substraten mit bis zu 6“Durchmesser mit der jeweiligen Technologie realisiert werden. Zur Abscheidung solcher röntgenoptischer Nanometer-Multischichten haben sich die Magnetron-Sputtertechnik und die Elektronenstrahlverdampfung etabliert. Sowohl für spezielle Materialkombinationen als auch zur Erzielung vorgegebener Schichtdickenprofile stellt das Verfahren der Puls Laser Deposition (PLD) eine interessante Alternative zu den dominierenden Technologien dar. Dazu wurde im Fraunhofer-IWS Dresden eine spezielle PLD-Konfiguration zur Großflächenabscheidung von Nanometer-Multischichten für röntgenoptische Anwendungen entwickelt. Das Verfahren erzeugt durch Ablation auf der Mantelfläche zylinderförmiger Targets eine definierte Relativbewegung zwischen Plasmafackel und Substrat. Damit können Multischichtsysteme mit homogener Schichtdickenverteilung oder mit vorgegebenen Schichtdickengradienten in einem automatisierten Prozess abgeschieden werden. Diese Großflächentechnologie wurde zur Abscheidung von Metall/Kohlenstoff- und Kohlenstoff/Kohlenstoff- Nanometer-Multischichten für röntgenoptische Anwendungen entwickelt und auf die Beschichtung von Substraten bis 6“Durchmesser aufskaliert. Im Ergebnis der Aufskalierung dieser Technologie können Röntgenspiegel, bestehend aus Kohlenstoff- und Metallabsorbern (z.B. Ni, W, Mo) in Kombination mit geeigneten Spacermaterialien (z.B. C, B4C, Si) mit mehr als 150 Perioden in einem automatisierten Prozess auf Substraten bis 6“Durchmesser abgeschieden werden. Dabei werden unter Verwendung der Großflächen-PLD (LA-PLD) Schichtdickenhomogenitäten besser 1% über 6“ Substratlänge, eine mittlere Abweichung der Einzelschichtdicken im Gesamtstapel von σD ≤ 10pm und eine Reproduzierbarkeit der mittleren Periodendicke zwischen zwei Abscheidezyklen von Δd/d ≈0.6% erreicht. Auf Grund ihrer röntgenoptischen Eigenschaften sind diese Nanometer-Multischichten hervorragend geeignet zur Herstellung röntgenoptischer Komponenten und Baugruppen für die unterschiedlichsten Spektralbereiche. Sie finden als Analysatoren, Monochromatoren und als strahlformende Baugruppen einen zunehmenden Einsatz in der Röntgendiffraktometrie und -reflektometrie, der Röntgenspektroskopie und in der Röntgenastronomie. So können unter Einsatz parabolisch gekrümmter Gradientenmultischichten, den sogenannten Göbel-Spiegeln, in kommerziellen Laborröntgengeräten monochromatische Parallelstrahlbündel für die verschiedensten Wellenlängen (z.B. für Cu Kα-, Mo Kα-, Co Kα-Strahlung) erzeugt werden. Die damit erzielbaren Verbesserungen hinsichtlich z.B. Intensität und einfacher Bedienbarkeit stellen eine neue Qualität in der Röntgenreflektometrie und -diffraktometrie mit Laborröntgenger"ten dar. Citing Literature Volume13, Issue4August 2001Pages 222-231 RelatedInformation

Fe/Al multilayers with different composition were prepared by conventional, direct-pulsed laser deposition (DPLD) and crossed-beam pulsed laser deposition (CBPLD). Films were studied by means of X-ray reflectometry, wide-angle X-ray scattering and X-ray absorption fine structure experiments. Ballistic simulations of the deposition processes were performed. It is found that adjacent Fe and Al layers are partially intermixed during the deposition, forming Fe–Al transition layers of a few nm in thickness. Both DPLD and CBPLD multilayers have comparable interfaces. In Fe-rich layers, a b.c.c. solid solution is formed. Al-rich layers of approximately 5 nm in nominal thickness are amorphous. DPLD samples have a higher Al content and a significant number of incorporated Al droplets.

By periodic variation of the deposition conditions nanometer multilayers of amorphous carbon films of varying density are deposited. Such carbon-carbon multilayers can be used for the preparation of X-ray mirrors of extreme irradiation stability and the optimization of tribological carbon coatings. Combining these techniques with concepts demonstrated in the preparation of fullerenes and nanotubes leads to graphitic films of very high hardness. Potential applications involve such different fields as field emission cathodes for flat panel displays and low-friction wear-protecting films.

Performance of Ni/C, Ni/B4C, Mo/B4C and W/B4C multilayers in the energy range E > 8 keV is considered by simulation of x-ray reflectivity and resolution of 1st order Bragg reflection at three different photon energies. The results indicate, that Ni/C and Ni/B4C multilayers show highest theoretical reflectivities of R > 80% for Cu K(alpha) - radiation and also above the Mo K-edge (E equals 20.04 keV) at 30 keV. For Mo K(alpha) -radiation a reflectivity of R > 90% can be achieved by the use of Mo/B4C multilayers. For applications, where period thicknesses d < 3 nm and high reflectivities are required W/B4C multilayers can be used. Theoretical values are compared with X-ray reflectometry results, which were executed at 75 period Ni/C, Ni/B4C and Mo/B4C multilayers, fabricated by pulsed laser deposition (PLD) technology on Si substrates. Amorphous or nanocrystalline structures of single layers, smoothest interfaces and high reproducibility of single layer thickness across the entire layer stack are the results of this high precision PLD process.