Lithography has been a key driver behind the increasing functionality of digital electronic devices. The patterning of features whose dimensions have been shrinking over time has been facilitated by decreases in the wavelength of the light used for imaging circuit patterns. Further reductions in wavelength are not expected beyond 157 nm, and non- optical methods of lithography will be needed to continue the progression to smaller feature sizes. Realization of the full potential of optical lithography will require many advanced techniques, such as optical proximity corrections and phase shifting masks. The cost of lithography also needs to be given consideration as new technologies are developed.

In this paper we present results related to the development of an alternative and non-destructive method for determining and mapping the etch pits density, in real time, by using digital imaging processing in association with an optical system. The density and distribution of the dislocation etch pits were obtained by the specular reflection produced by either a He-Ne laser or a white light on an etched semiconductor material surface. As the pits related to dislocations have a typical geometric form according to crystallographic plane of the surface they become more evident than other defects and, as a consequence this allows to reach selectivity for this specific defect by the system. The efficiency of the suggested method was accomplished by comparing the results obtained with conventional analysis done by optical microscopy. The proposed automated system demonstrated to be capable of covering large surface areas very rapidly, if compared to a traditional method in view of the fact that by using optical microscopy the density and distribution of defects can be determined only in the small regions which makes the mapping of the entire sample laborious. Furthermore, this system can be easily adapted to a line production providing direct qualitative and quantitative information on the substrate quality.

This paper addresses the possibilities and recent achievements in increasing significantly the resolution of optical microscopy for wafer and mask inspection and metrology. DUV microscopes operating at 248 nm wavelength already offer a feature size resolution down to 0.08 micrometers . Photon tunneling microscopy (solid immersion optics) allows to apply the higher resolution of immersion optics without bringing the immersion into contact with the specimen. First results are shown. A special illumination mode in laser confocal microscopy, the so called doughnut illumination, appears to have the potential for increasing the resolution by about 30% compared to classical laser confocal microscopy. It is shown that in the combination of these three methods an ultimate feature size resolution of about 25nm may be achieved- at least theoretically. The future will show if what seems to be physically feasible can be transformed to technical solutions.

A new method of doping profile reconstruction, starting from infrared spectroscopic measurements, is presented and numerically analyzed. We have developed, relying on the scattering integral equations, a new formulation allowing to directly relate the optical reflected intensity to the free carriers concentration. This formulation has been used to develop an iterative algorithm for dopant profiling. The main advantage of our approach is that the unknown dopant file is modeled by a finite series of basic functions. As the series expansion allows to describe a wide class of profiles, it is not necessary to choose a priori the functional form of the doping profile (e.g. exponential function, gaussian function, error function etc.). This allows to reconstruct the actual profile, regardless of its similarity with the expected one.

We present a technique in which atomic force microscopy (AFM) at ultrasonic frequencies is used to measure the contact stiffness between an AFM tip and thin films on silicon substrates. In this method, the resonance frequencies of the cantilever flexural modes are used to determine the tip-sample contact stiffness. We present experimental results, showing that the contact stiffness is highly sensitive to the thickness of thin metal and polymer films. These results are compared with those from out theoretical model, which we call the Contact Stiffness Algorithm (CSA), that may be used to calculate the contact stiffness between an AFM tip and an arbitrarily layered sample. Unlike transmission electron microscopy (TEM) or scanning electron microscopy (SEM) on a cross-section of the sample, this film thickness measurement technique is non- destructive. It is also capable of high lateral spatial resolution, provided that a sharp AFM tip is used. We present images of a photoresist film on silicon with contrast resulting from the elastic properties of the sample.

In this paper, a testing method for optical polished surface in level instrumentation and supersmooth surface in soft x- ray system using Atomic Force Microscope (AFM) is presented, and some testing results reached to nanometer RMS are listed. In the paper it is indicated that, different size of polished platforms are formed as difference of optical polished method and period. Important applications of AFM testing method for improving optical polished technology and obtaining supersmooth surface are introduced in the paper.

Optical scattering is a fundamental loss mechanism in high power laser applications, especially for optical systems in the DUV/VUV spectral range. For recording of total optical scattering (TS) several standardized measurement procedures which are optimized for the UV/VIS/NIR spectral range, are already existing. In this study, the problems of total scatter measurement techniques in the DUV/VUV will be discussed in respect to their practicability. In addition improvements for the standardized measurement procedures will be presented. TS measurements on selected coated laser components for 157nm and 193nm will be discussed in view of the loss mechanisms in thermally evaporated dielectric multilayer coating systems. The change or rms surface roughness of the components in dependence of the physical thickness of coated thin films will be described with the help of TS measurements. Also, the TS results for bare substrates in VUV and VIS will be compared and considered in relation to applications in short wavelength ranges.

This paper reports on an instrument designed to measure the total backward and forward scattering of optical components down to the DUV/VUV spectral region. The system is based on a Coblentz sphere imaging the light scattered into the backward or forward hemispheres within an angular range from 2 degree(s) to 85 degree(s) onto the detector according to ISO/DIS 13696. The equipment divides into two set-ups, one operating in air at several wavelengths from 10.6 micrometers to 193 nm, the other one working in a vacuum/nitrogen at 157 nm and 193 nm. The system is fully automated and capable of scanning large sample areas. Both a deuterium lamp and an excimer laser can be used as radiation sources at 193 nm and 157 nm. Results of measurements on fluoride multilayer coatings and CaF₂ substrates are presented.

The control and measure of losses phenomena is a crucial point for high quality thin film optical components. The knowledge of the statistical and spatial distributions of optical absorption and scattering can give precious information about the structure, the size, the origin and the event frequency of the defects which may play an important role in laser damage for example. The non uniformity of losses, the existence of local defects have led us to perform simultaneous absorptance and scattering mappings. Today, an uplifted set up and original protocols are capable of providing simultaneous mappings of absorption and partial scattering for optical coating s with different spatial resolutions. A micronic spatial resolution is reached, studies and controlled using contrast in absorption targets specially designed for that check by Ion implantation in bulk fused silica substrates. The detectivity threshold is brought down to 0.1 ppm for absorption and 0.01 ppm for partial scattering mapping. The spatial windows investigated can range between micronic area for the study micro of defects as well as centimetric areas in order to check the uniformity of losses. Furthermore, we have developed different processes and numerical tools in the aim to accurately evaluate and study specific parameters: simulation of measurement processes, statistical values of both absorptance and partial scattering over the desired area, tracking down of local defects and estimation of its density, measurement of losses level inside these defects and outside thanks to a mapping zoom technique.

The potentialities of the x-ray scattering methods (XRS) for quantitative testing of supersmooth surfaces, thin films, and multilayer structures are discussed. The results of the surface roughness study with the use of XRS technique in hard and sort x-ray spectral regions are compared with independent measurements of the roughness by atomic force microscopy (AFM). It is demonstrated that the results obtained by XRS and AFM are in a very good agreement in spite of different physical principles and underlying the methods. XRS technique is applied for the roughness study of thin films which are used in applications for x-ray and UV optics. The XRS method is demonstrated to enable quantitative evaluation of PSD functions of both the film interfaces and the correlation between the substrate and film roughnesses. X-ray investigations of the correlation of the roughnesses of short-period multilayer structures are discussed as well. The use of the whispering gallery effect is demonstrated to extend the XRS method to control of the concave surface roughness.

For the roughness characterization of optical surfaces a new procedure based on the analysis of their power spectral density (PSD) functions has been developed. The method consists of the fitting of the PSD obtained from Atomic Force Microscopy measurements at different scan sizes to mathematical models. With this procedure the micro- structural properties of optical surfaces and coatings can be represented by a reduced set of numbers that correspond to the characteristic parameters of the mathematical models. For optical coatings this method allows a separate study of the influence of the substrate and layers on the overall sample roughness. As an example, the method is applied to MgF₂ and LaF₃ films for VUV applications. We investigated a set of single layers deposited onto superpolished Caf₂, fused silica and Si substrates. The samples were deposited by ion beam sputtering, boat and e- beam evaporation. A comparison of the influence of the substrate on the development of the roughnesses and lateral structures has been performed, as well as a study of the dependence of the roughness properties of the coatings on the deposition process. Complementary investigations of roughness-related scattering consisting of measurements of Total Scatter at 193 nm and 633 nm and calculation of expected scattering based on the theory are presented.

In many advanced fields of optical technology, progresses are extremely dependent on reliable characterization procedures employed for quality assessment in volume manufacturing as well as for the optimization of high performance optical components. With the rapid development of laser technology and modern optics, especially optical metrology gained of importance for the quality management in the industrial production environment and also for research in optical components. Besides absorption and scatter losses, the spectral characteristics and laser induced damage thresholds are considered nowadays as common quality factors, which are often indicated in optics catalogues and are considered by the customers for the design of optical systems. As a consequence of this trend, standardization of measurement procedures for the characterization of optical components became a crucial point for the optics industry and for critical applications of optical components in laser systems as well as conventional optical devices. During the last decade, adapted standard measurement techniques have been elaborated and discussed in the Technical Committee ISO/TC 172 of the International Organization for Standardization (ISO) resulting in practical International Standards or Draft Standards for the measurement of optical absorption, scattering, reflectance and laser induced damage thresholds. In this paper, the current state of standardized characterization techniques for optical components is summarized. Selected standards for the measurement of absorption (ISO 11551), scattering (ISO/DIS 13696) and laser induced damage thresholds (ISO/DIS 11254, Parts 1 and 2) will be described and discussed in view of recent trends in laser technology and its applications in semiconductor lithography.

The optical characterization of materials in thin film phase is a standard task in the field of coating technology. One typical problem is the optical characterization of a single layer of material deposited on a well-known substrate. Provided the physical model considered for the modeling is correct and the available experimental date (usually spectrophotometric or ellipsometric spectra) are accurate, a precise optical characterization is quite straightforward. However, there are experimental circumstances where several samples have been coated under very well defined conditions. As when they have been obtained in the same coating run, so that no differences are expected due to the positions of each individual sample inside the chamber during the deposition process. The aim of this work is to present an improved procedure for the optical characterization of the material deposited under the very well controlled conditions explained above. The basis of our method is to use the a priori information about the identical nature of all the samples, introducing all the spectrophotometric and/or ellipsometric data available from optical properties of the layers, as compared with the separate (individual) characterization of the samples. We will illustrate our procedures for MgF₂ films in the range 200-800 nm.

We present an extremely simple and powerful test set-up for measuring the position and the focal line straightness (lateral) and flatness (longitudinal) of cylindrical lenses, in particular of very long cylindrical lenses. Measurement results are presented for 330 mm and 650 mm long plano- convex cylindrical lenses with a focal length f approximately equals 48 mm, showing that a (lateral) straightness measurement accuracy of about +/- 1 micrometers is achieved easily with a set-up using not much more than a laser, a simple beam deflector from a barcode scanner, a PSD (position-sensitive photo diode) with associated electronics and a translation stage. A fully automated cylindrical lens test set-up version, using a PC for control and data processing will be explained. For the 330 mm long cylindrical lenses, the lateral straightness showed better than between 3 and 10 micrometers (peak to peak) and the longitudinal flatness between 20 and 80 micrometers (peak to peak) without corrective bending. It will be demonstrated that the aberration coefficients, as measured by this physical ray tracing approach, are in accordance with the results from numerical simulation by means of a commercially available ray-tracing program.

The problem of measuring the slope and figure of large, slightly non-flat or steep complex surfaces with nanometer and sub-nanometer accuracy has not been generally solved. Existing systems such as interferometers, three-coordinate measuring machines and slope measuring facilities do not fulfil the requirements for very high accuracy: related topics will be discussed: intrinsically two-dimensional methods vs. scanning methods, external references and their influences, the kind of measurements signal, errors of scanning stages and their influences, whole-body movements of the artifact and their influences, long-time stability of the facility. Very recently, particular measurement principles have been proposed, which focus on the principles of traceability and avoidance of error influences and are intended for determining slope and figure with ultra- precision. These methods are based on the direct measurement of slope difference and curvature, and in contrast to other methods, are directly traced back to the base units. They do not depend on external references and offer the advantage that the errors of the stages and whole- body movement of the artifact do not influence the accuracy of measurement. Application of these methods eliminates the influences of the first- and second-order errors of the facility. In addition, absolute measurements are traced back to relative measurements and long-time stability is achieved by constant recalibration of the sensor. The question which remains to be answered and which will be discussed is that of the basic or natural limits of systems intended for measuring slope and figure.

A special calibration tool has been developed for a CCD camera based vision system in an automatic assembly machine. The machine is used to attach orifice plates onto a silicon wafer in a production process. The center locations of the positioning circular holes on the plate must be controlled accurately to coincide with those on the wafer die before they are attached together by UV curing. Although CCD camera based vision systems are widely used for accurate positioning and dimensional measurements in precision engineering, electronics and semiconductor industry, their calibrations are normally done by artefacts with plane patterns. These artefacts are therefore restricted to only two dimensional measurements. The calibration tool we developed was to check the positioning accuracy of circular objects in a two-layered structure. It can also be used to determine parallax errors, non-linearity and spatial non- uniformity errors as well as repeatability of the vision system with an uncertainty at sub-micrometer level. The design, calibration and performance of the tool are described in detail in this paper.

Interference microscopy is the primary tool used in the Data Storage industry for air bearing surface (ABS) and pole tip recession (PTR) measurements. ABS parameters include crown, camber and twist (CCT), and affect the behavior of the magnetic head as it flies above the spinning disk. PTR parameters describe the relative height of the writing poles and reading shield. The roadmap for several types of measurements will be discussed in this paper.

Colossal Storage Inc. has patents on new ways of non-contact reading and writing with non destructive reading of information to a ferroelectric molecule. These methods will be used to develop the worlds first 3D volume holographic mass storage device, only 2D concepts are discussed in abstracts as 3D is under confidential research.

Ellipsometry is a sensitive optical technique for non- invasive in-situ (in any optically transparent environment) and ex-situ (in air) characterization of surfaces, interfaces, and thin films which is based on measurement of the polarization of light before and after reflection from a given sample at different angles of incidence and as a function of wavelength. The spectral range of spectroscopic ellipsometry (SE) -typically 1-6eV of photon energy- has been extended to the mid and far IR on one side and to the VUV, EUV, and X-ray region on the other. Significant advances and sophistication of available instrumentation and supportive software have resulted in extensive use of ellipsometry in biology, chemistry, physics, materials science and engineering, and industrial applications over the past two decades. Fast ellipsometers are used for real- time on-line monitoring and feedback process control of various thin films and for the fabrication of pre-engineered multilayer and graded-composition structures. As a metrology tool, ellipsometry yields information on dielectric functions of layered optically isotropic or anisotropic materials, film thicknesses, interface roughnesses, and compositions (void and alloy fractions) and depth profiles of inhomogeneous thin films.

Optical properties of thin films and bulk materials at short wavelengths, including 157 nm and shorter, are needed for development of new lithographic processes, new fundamental science, and new metrology in the semiconductor, optical and data storage industries. Variable angle spectroscopic ellipsometry offers non-destructive and precise measurement of thin film thickness and refractive index in the wavelength range from 140 nm to 1700 nm (0.73 eV to 8.9 eV). The addition of short wavelengths allows analysis of multilayer dielectric stacks, often difficult to do using visible spectroscopy alone. Another major application is in study of wide bandgap materials such as SiC and GaN related compound semiconductors for blue lasers and detectors. This paper reviews the present status of spectroscopic ellipsometry applications in the vacuum ultraviolet.

Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multi layers. Instrumentation for the next generation of UV lithography at 157nm requires special optical set-up since O₂ and H₂O are extremely absorbing below 190nm. The new system works into a purged glove box to reduce the oxygen and water contamination in the part per million range. The optical set-up includes a premonochromator in the polarizer arm to avoid photo bleaching. The system works in rotating analyzer configuration to minimize the parasitic polarizations. Ellipsometric and photometric measurement versus wavelength from 145 up to 630 nm and angle of incidence can be performed. The proposed paper will present in details the new system with some first experimental results in the field of micro lithography. Results are compared to those obtained with more standard UV ellipsometers and correlated to other measurements obtained with grazing x-ray reflectance technique.

In situ spectroscopic ellipsometry is a useful tool for characterizing the kinetics of aluminum oxide growth. Thin aluminum films were deposited on thermally oxidized silicon wafers and dosed with oxygen. Real-time in situ ellipsometry was used to monitor both natural and UV oxidation processes using different oxygen pressures. The raw data was subsequently fit to an optical multi-layer model. The ellipsometric data was sensitive to changes in the oxide layer thickness of much less than a monolayer. With the time scale of our data acquisition two different growth regimes were seen in the fitted data in agreement with the Mott-Cabrera model of oxidation. The growth rate became larger with the assistance of light from the UV lamp.

High-k gate dielectric films with equivalent oxide thickness (EOT) of 3 nm or less are becoming the main theme of research and development in ultra-large-scale integrated circuits industry with device dimensions scaled down to less than 130 nm. Among the high-k gate dielectric materials hafnium dioxide (HfO₂) is very promising with its high dielectric constant (approximately 30) and stability in contact with Si. The samples were prepared with a DC magnetron-reactive sputtering method and subsequently annealed in the furnace with a temperature range of 500- 850 degree(s)C. The thickness of the HfO₂ varied from 3.5- 18nm with a hafnium silicate interface layer of approximately 1 nm. The electrical measurement showed that the breakdown voltage is inversely proportional to the physical thickness, suggesting the breakdown process occur at the HfO₂ thin film rather than in the interface layer. To measure the physical thickness of hafnium dioxide and hafnium silicate interface simultaneously, a research grade bench top rotating compensator spectroscopic ellipsometry (RCSE) in the wavelength range of 195-915 nm was used. The dispersion of HfO₂ film was characterized with a two-peak critical point (CP) model and the dispersion of the interface layer of hafnium silicate was characterized with a five-peak CP model. An interface layer thickness of 0.7-2 nm was found for all hafnium dioxide films on Si, depending on the process conditions such as annealing temperature and oxygen flow rate. The same wafers measured by RCSE were later studied by transmission electron microscopy (TEM). The thickness of hafnium dioxide and hafnium silicate determined by TEM is in good agreement with the noninvasive RCSE method.

Solid immersion microscopy, an optical method with the capability for super-resolution has received a considerable amount of attention in the literature in the past few years. The main targets of the technique are lithography, pattern inspection (including critical dimension measurement) and data storage. The classical theory predicts a resolution gain proportional to the refraction index of the solid immersion lens. The intent of the paper is to prove this prediction by means of simulations and to find optimum measuring conditions. To this end, we present a very efficient, rigorous modeling method. By means of this method, we show that the inclusion of evanescent waves is crucial for the resolution gain. This is detailed with different excitation and detection schemes. Further more, we investigate the impact of polarization and different sample types.

Tantalum oxynitride (TaO_xN_y) thin films were prepared in a RF magnetron sputtering system. The film properties with various sputtering parameters such as RF power, gases ratio, and substrate temperatures were investigated. In comparison with tantalum oxide films, the film properties are strongly affected by the nitrogen content. The microstructure studied by XRD and TEM revealed amorphous. When the nitrogen content varied from 20% to 80%, the deposition rates increase from 5.5 to 11.8 nm/min. Because of the stronger affinity of oxygen to Ta than nitrogen does, the oxygen content of the films is always higher than nitrogen content, even if the partial pressure of nitrogen is higher than that of oxygen. The highest refractive index (n) of the tantalum oxynitride film is 2.29 and the extinction coefficient (k) is nearly zero. The refractive index is inversely proportional to the substrate temperature. The mean square surface roughnesses measured by SPM (scanning probe microscopy) for as-deposited at room temperature and 300 degree(s)C were 0.56 nm and 0.17 nm, respectively. By way of a micro-electro-mechanical system (MEMs) technique- the cantilever beam method, the films show a compressive residual-stress state and the coefficient of thermal expansion (CTE) is also measured. The thermal properties were deeply affected by the nitrogen. Thus, TaO_xN_y films with suitable x,y values are good candidate dielectric materials for optical or magneto- optical purposes.

The purpose of this paper is to improve the metallic wire diameter measurement. The size of some thin wires and slits has been achieved using the spectrogoniometer which represents good alternative system of detection. The fact that, the technique of measurement may be regarded as bringing more calibrated diameter. Since it provides wide range of detection, possibility to control the output signal readjusting a minimum of points per fringe and few image error to deal with comparing to other measurement techniques. The target-arm of detection rotated and drifted by a stepping motor of high resolution. As we know the diffraction of the thin wires using Fraunhofer technique is very suitable for an automatic control in the process of fabrication. Whereas, the more precise diameter we want the more deeper study is required (both theory and experiment). Concerning the physical approach of the phenomena, we fit our data to a polynomial of the third order. The error of each coefficient is given. The odd term presented in the polynomial function may be due to the deviations from the ideal properties of the components. Once the measurements are made, a special care of the experimental data is required in order to deduce the right diameter confining us only to the minima of the diffraction pattern. The wire diameter accuracy depends not only how good is our signal but as well how good our analysis of data.

It is demonstrated that the simplest model of a surface, assuming step-like variation of the dielectric permeability at a vacuum-matter interface, does not permit the quantitative description of all the features of x-rays reflection and scattering observed in experiment, even though the effects of the surface roughness are taken into consideration accurately. These features are much more pronounced for metals having a large number of the conductivity electrons which are bound slightly with individual atoms. Evidently, the wave function of the electron gas of a metal cannot abrupt sharply at a surface but decreases gradually into vacuum at a distance of several angstroms. To validate or disprove the hypothesis for the presence of a near surface transition layer of the electron density in metals, a set of experiments is performed. Reflection and scattering of hard and soft x-rays, and cold neutrons (which are sensitive to nuclear density distribution and insensitive to the electron one) from metal samples are measured. The independent measurements of the surface micro-topography are performed with the use of atomic force microscopy. The results obtained demonstrate the presence of a near surface layer, which is caused by gradual change of electron density, with a thickness of several angstroms.

We discuss principles of optical surface quality assessment. The micro topography of well polished fused silica, CaF₂ and Si surfaces was examined locally and by covering large sample areas. Power Spectral Densities (PSD) were used for consistent roughness description. Subsurface damage was detected by a modified white light interferometer technique and total scattering measurement.

The intrinsic absorption of fluoride coating materials tends to higher values in the DUV/VUV spectral range. In respect to applications of this material class for DUV/VUV multilayer systems, like high reflecting mirrors and anti- reflective coatings, the control of absorption is essential for further improvement of the coating quality. However, the reliable determination of absorption losses by photometric techniques has to overcome various obstacles caused by light absorption in air, scattering effects of the coating, and absorption related to contamination of the employed fluoride material. In this contribution spectrophotometric measurements for the characterization of optical data of MgF₂ and LaF₃ single layers and multi layer systems are presented. An advanced VUV/DUV-spectrophotometer, which has been developed at the Laser Zentrum Hannover for the optimization of thin film production processes, is described. The subsequent optical data evaluation for fluoride single layer coatings is reported and the optical data, n and k, of MgF₂ and LaF₃ for the spectral range from 130 to 660 nm are presented. Transmittance and reflectance measurements of multilayer coating systems are compared to theoretical calculations for these systems on the basis of the evaluated optical data of the single layers. Observed deviations are discussed under respect of contaminations of the fluoride layer systems.

In the course of the rapid progress of DUV/VUV lasers and their employment in semiconductor lithography, micro material processing, and medical surgery systems, the characterization of optical components in this spectral region gains of increasing importance. The precise determination of the optical properties, such as reflectance (R) and transmittance (T), is essential for further progresses of the components. Currently, standardized procedures for measurement of R&T are described in the international standard draft ISO/WD 15368, which is optimized for the whole wavelength range above DUV. In the DUV/VUV spectral range, scatter losses caused by the surface and bulk of the components increase with decreasing wavelengths. This effect is not considered in the standardized measurement procedures for T and R. In this study, a spectral photometer device, which has been developed at Laser Zentrum Hannover, will be presented. The set-up allows measurements of total reflectance for a defined acceptance angle range. In the current state, the DUV.VUV-photometer covers a spectral range from 115nm up to 300nm. Investigations on the scatter behavior of optics for this spectral range indicate a need for precise separation between ordinary reflected or transmitted beam and scattered radiation on the test samples. The dependence of the R and T values on the collection angles will be illustrated.

New particle scanner capabilities are needed to meet requirements for the next generation of devices in the semiconductor industry. Among these, defect identification and sizing are very important. This paper shows the key role of accurate scanner calibration to achieving these advances in scanner capability. An example, using modeled results from a hypothetical scanner geometry, analyzes the ability to discriminate surface pits from silicon particles for differing levels uncertainty in the PSL calibration spheres.

We present an ellipsometric measurement set up designed for fast surface mapping. The system consists of a HeNE laser, a linear polarizer, a recently developed grating polarimeter and a translation stage for moving the sample. The system allows the spatially resolved measurement of the ellipsometric angles (Delta) and (Psi) . For transparent single layer coating, refractive index and film thickness from the measured values can be calculated. For multilayer coatings where the determination of all the optical properties is not possible, information on the coating homogeneity can be gained.