DE102004012161B3 - Imaging Ellipsometer with Synchronized Sample Feed and Ellipsometric Measurement - Google Patents

Abstract

A method of imaging, ellipsometric detection of a mainly flat extended sample assembly (10), the DOLLAR A - the sample arrangement at least partially illuminated by means of a lighting arrangement with illumination light adjustable polarization properties under a sample normal tilted illumination angle (phi), DOLLAR A - of illuminated areas of Sample (10) reflected detection light in a, under a suitable, normal to the sample inclined angle of illumination (phi) arranged polarization sensitive detection device on a controlled readable detector (12) having a plurality of ordered, photosensitive detector elements, DOLLAR A - parameters of mapping of sample areas the detector (12) are varied and DOLLAR A - at least one read-out region (12a; 12b) of the detector (12) in a synchronous manner to the variation of the imaging parameters for the generation of sample areas is read out images, wherein DOLLAR A - the sample arrangement (10) is moved by motor relative to the detection arrangement, wherein successively different sample areas (10a; 10b) are imaged onto the same detector read-out area (12a), DOLLAR A - the detector read-out area (12a) is read in synchronism with the movement of the sample (10) and DOLLAR A - successively read from the detector read-out area (12a). Partial images (15a-15f, 15x, 15y) to a result image (14) are composed.

Description

• – die Probenanordnung wenigstens bereichsweise mittels einer Beleuchtungsanordnung mit Beleuchtungslicht einstellbarer Polarisationseigenschaften unter einem zur Probennormalen geneigten Beleuchtungswinkel beleuchtet wird,
• – von beleuchteten Bereichen der Probe reflektiertes Detektionslicht in einer unter einem geeigneten, zur Probennormalen geneigten Beleuchtungswinkel angeordneten, polarisationssensitiven Detektionsanordnung auf einen gesteuert auslesbaren Detektor mit einer Mehrzahl geordneter, photosensitiver Detektorelemente abgebildet wird,
• – die Probenanordnung relativ zu der Detektionsanordnung motorisch bewegt wird und
• – wenigstens ein Detektor-Auslesebereich, auf den nacheinander unterschiedliche Probenbereiche abgebildet werden, zeitlich korreliert zu der Bewegung der Probenanordnung zur Erzeugung von Probenbereiche repräsentierenden Bildern ausgelesen wird.

The invention relates to a method for imaging, ellipsometric detection of a mainly flat extended sample arrangement, in which

• The sample arrangement is illuminated at least in regions by means of a lighting arrangement with illumination light of adjustable polarization properties under a lighting angle inclined to the sample normal,
• Detecting light reflected from illuminated areas of the sample in a polarization-sensitive detection arrangement arranged under a suitable illumination angle inclined to the sample normal to a control-readable detector with a plurality of ordered, photosensitive detector elements,
• - The sample assembly is moved relative to the detection device by motor and
• At least one detector read-out region, onto which successively different sample regions are imaged, is read out in time-correlated manner with respect to the movement of the sample arrangement for generating images representing sample regions.

• – eine Beleuchtungsanordnung zur wenigstens bereichsweisen Beleuchtung der Probe mit Beleuchtungslicht wählbarer Polarisationseigenschaften unter einem zur Probennormalen geneigten Beleuchtungswinkel,
• – eine unter einem geeigneten, zu der Probennormalen geneigten Detektionswinkel angeordnete Detektionsanordnung zur polarisationssensitiven, abbildenden Detektion von Detektionslicht, welches von beleuchteten Bereichen der Probe reflektiert wird, umfassend einen gesteuert auslesbaren Detektor mit einer Mehrzahl von photosensitiven, geordneten Detektorelementen,
• – einen verfahrbaren Probenträger, mit welchem die Probe bewegbar ist, dass auf denselben Detektor-Auslesebereich abgebildet werden,
• – Steuermittel zur Steuerung des Auslesens wenigstens eines Detektor-Auslesebereichs, auf den nacheinander unterschiedliche Probenbereiche abgebildet werden, in zeitlich korrelierter weise zu der Bewegung der Probe.

The invention further relates to an imaging ellipsometer for imaging, ellipsometric detection of a mainly flat-extended sample comprising

• A lighting arrangement for at least partial illumination of the sample with illumination light of selectable polarization properties below a lighting angle inclined to the sample normal,
• A detection arrangement arranged below a suitable detection angle which is inclined to the sample normal for the purpose of polarization-sensitive, imaging detection of detection light which is reflected by illuminated areas of the sample, comprising a controllably readable detector having a plurality of photosensitive, ordered detector elements,
• A movable sample carrier, with which the sample can be moved, that is imaged onto the same detector read-out region,
• - Control means for controlling the readout of at least one detector read-out region, are sequentially displayed on the different sample areas, in time-correlated manner to the movement of the sample.

The The invention finally relates on a quality assurance module for detecting manufacturing defects in a product manufacturing device.

For the imaging of very thin and especially transparent samples, ellipsometry has established itself as a powerful measuring principle. The basic principle of well-known ellipsometric methods can be most easily understood from the schematic sketch of 1 explain. A light source L with associated optics generates a light beam that illuminates a sample arrangement at least in regions at an angle φ. The angle φ is usually measured against the sample standards and is selectable in conventional devices. In addition to the light source and a suitable light-guiding optics, for example, a suitable lens and / or mirror system, the illumination arrangement comprises polarization-relevant elements with which the polarization properties of the illumination light can be modified. In the illustrated scheme, a polarizer P and a compensator C, which may be formed for example as quarter-wave plate, are used. The sample arrangement is therefore illuminated at least in regions with illumination light of known polarization properties. Also at an angle to the sample normal, a detection arrangement for detecting detection light is provided. Since light used as detection light is generally used by the illuminated sample areas, the angle of the detection arrangement to the sample normal, following the law of reflection of the ray optics, generally also corresponds to the angle φ. A suitable light-conducting optics and other polarization-relevant elements (in the illustrated scheme, an analyzer A) detection light is directed to a photosensitive detector D. The intensity detected on the detector D is inter alia dependent on the relative adjustment of the polarization-relevant elements to each other. The choice of the angle φ also influences the detected intensity.

It are imaging and non-imaging applications of ellipsometry known. While at non-imaging ellipsometry optics and detector on the Illumination of a single point or the detection of reflection light from this point are aligned in the imaging Ellipsometry larger sample areas illuminated simultaneously and an imaging optics O is provided, which correspond to individual points of the illuminated area assigns photosensitive detector elements, which make up the detector is structured in an orderly manner.

To carry out an ellipsometric measurement, in particular two basic principles are known. For example, multiple individual measurements with different relative setting of the polarization-relevant elements to each other and / or different settings of the Angle φ performed and values of interest are derived according to the physical relationships known in the art from the resulting sequence of measurement units (individual readings in non-imaging or single images in imaging application). In contrast, in the so-called null ellipsometry, which is used in particular in imaging applications, the polarization-relevant elements are adjusted relative to one another such that certain characteristic values of a result image, for example a contrast between two imaged sample areas, assumes a particular value. For example, in the inspection of so-called microarrays or biochips in which the quality of the application of a pattern of biomolecules on a carrier substrate is to be checked, the polarization-relevant elements are adjusted relative to one another such that the effectively usable contrast between molecule-occupied regions and free Areas of the carrier substrate is maximized. Faulty forms of molecule-occupied areas are then particularly simple and in particular recognizable without performing a complex, multi-step process.

There the sample arrangement in all ellipsometric methods under illuminated an angle deviating from the sample normal and is observed, the unavoidable in imaging applications Difficulty that adjacent sample areas simultaneously illuminated and simultaneously detected by the detector, different distances to the detector. To make a "sharp" image of all areas on the detector to enable would have to be in the detection device used imaging optics with extreme depth of field become. This leaves not in a general way with the other demands for light intensity, higher spatial resolution and flexible choice of viewing angle. Man bypasses this difficulty therefore usually in that successively several, mutually adjacent readout areas of the detector for generating result fields be, where before each reading of a partial image, the imaging optics refocused, so that in each case on the sample area is "armed", the on the next one is read out to be read detector read range. this has the disadvantage that the corresponding imaging optics mechanically elaborately executed must become. Also lets This approach is bad for Automate the acquisition of larger sample areas.

Out WO 96/24034 A1 discloses a method according to the preamble of claim 1 and a device according to the preamble of claim 8, which serve the imaging ellipsometry. there is a particular oscillating movement of the sample during the Integration time of the imaging detector provided to a Averaging a speckle pattern caused by interference from at the Sample scattered partial beams of the illumination light with each other arises, to reach. In this respect there is a temporal correlation between the movement of the sample and the reading of the detector. However, the known device and the known method are not suitable, the above explained Problems of automatically recording large image areas with the same staying high image sharpness to solve. On the contrary, it comes through the sample movement during the integration time of Detector to a strong "blurring" of the generated image and thus to a significant decrease in image sharpness.

DE 694 15 641 T2 ( EP 0 652 415 B1 ) discloses a scanning ellipsometry device in which an illumination beam is guided by beam deflectors over the sample to be examined. The disadvantage here is the high mechanical complexity which is to be driven for an exact beam deflection, as well as the high optical complexity required for the correct focusing of the illumination beam moving over the sample and for the "sharp" imaging of the likewise moving, reflected beam onto a two-dimensional one Detector is required.

US 6,052,188 discloses a non-imaging, ellipsometric spectral analysis apparatus that utilizes a two-dimensional detector to acquire polarimetric and spectrometrically resolved result arrays for a single sample point.

It It is an object of the present invention to provide a generic method in such a way that an automation, in particular for industrial application, simple and inexpensive possible.

It It is another object of the present invention to provide a generic device in such a way that the total result images constructed from partial images be generated in an automated manner, in particular, if the surface to be imaged exceeds the field of view of the detector.

• – der Detektor-Auslesebereich (12a) synchron zu der Bewegung der Probe (10) ausgelesen wird, und
• – nacheinander aus dem Detektor-Auslesebereich (12a) ausgelesene Ergebnis-Teilbilder (15a-15f, 15x, 15y) zu einem Ergebnisbild (14) zusammengesetzt werden.

The first object is achieved in conjunction with the features of the preamble of claim 1, characterized in that

• The detector readout area ( 12a ) in synchronism with the movement of the sample ( 10 ), and
• - one after the other from the detector read-out area ( 12a ) read result fields ( 15a - 15f . 15x . 15y ) to a result image ( 14 ).

This inventive method principle dissolves completely from the hitherto pursued idea of "sharpening" different image areas. Instead of of which the sample itself becomes synchronous with the readout of the detector Way proceed. This has the advantage that the imaging optics correspondingly simple and with respect to visually relevant boundary conditions Optimized can be configured.

conveniently, the sample arrangement becomes linear and perpendicular to the sample normal and moved parallel to the plane of incidence of the illumination light. The movement can take place continuously or stepwise. A continuous movement of the sample arrangement is useful Applications in which the time factor is critical. It is only feasible if the lighting conditions a sufficiently short Allow integration time of the detector, so that despite the continuous Movement the generation of sufficiently sharp fields is possible. A gradual movement of the sample arrangement, however, allows longer Integrationszeiten of the detector without the danger of "smearing" of partial images.

Especially the polarization properties of the illumination light are preferred and the polarization sensitive detection device at the beginning of the Method relative to each other adjusted such that a result image a reference sample arrangement with respect to at least one image characteristic shows an extreme value. This image characteristic is preferably a Contrast between two selected sample areas. This embodiment the method according to the invention may find particular application in the so-called null-ellipsometry. in this connection can For example, the settings are made so that between two adjacent areas of the reference sample no or a minimum Contrast is apparent, allowing the appearance of a contrast between equivalent areas a measured sample of a deviation from a target value. On the other hand, the adjustment can be made such that between two sample areas of a reference sample a maximum contrast arises, so that in the actual measurement, for example, certain Forms of sample areas are particularly well recognizable. conveniently, forms the result image, which preferably the user via a Display device is displayed, a kind of continuous window. This means that a result image constructed from result sub-images each of the previously constructed result image without the first read out Result-frame and added to a newly read result field, equivalent. If the resulting sequence of result images, which can also be stored digitally and / or analogously, gives the impression of an observation window through which the sample is passed through.

The Synchronization of motor sample feed and readout of the Detector range can be ensured in different ways. In the simplest case known motion data, e.g. Speed, Duration of a movement step, feed distance during a movement step etc. used to control the detector readout suitable. cheaper although technically a little more elaborate, it may be out of the actual Sample movement over Suitable sensors Trigger signals for the control of the detector readout to generate. The problem with both variants may be that the readout control only on mechanical motion parameters based. However, it may be that, for example due to bumps of the substrate, undesirable added optical aberrations. For example, one would have Wave in the substrate a change of the reflection angle result, which is due to lack of appropriate Adjustment of the detection beam path in a shift of the imaging area the sample would precipitate on the detector.

• – in einem Referenzbild anhand von Bildinformationsparametern eine Interessenregion (ROI: region of interest) definiert und deren Position und/oder Form in einem ersten Teilbild bestimmt wird,
• – in einem zweiten Teilbild nach einer Verschiebung der Probe die Position und/oder Form der ROI anhand der gleichen Bildinformationsparameter ermittelt wird,
• – das zweite Teilbild wenigstens ausschnittweise durch Translation, Rotation, Stauchung und/oder Streckung derart korrigiert wird, dass die Position und/oder Form der ROI in dem zweiten Teilbild mit der Position und oder Form der ROI in dem ersten Teilbild übereinstimmt, und
• – positions- und/oder formkorrigierte Teilbilder bzw. Ausschnitte davon zum Aufbau des Ergebnisbildes verwendet werden.

In a particularly favorable embodiment of the method according to the invention it is therefore provided that

• In a reference image on the basis of image information parameters a region of interest (ROI) is defined and its position and / or shape determined in a first partial image,
• In a second partial image after a displacement of the sample, the position and / or shape of the ROI is determined on the basis of the same image information parameters,
• The second partial image is at least partially corrected by translation, rotation, compression and / or extension in such a way that the position and / or shape of the ROI in the second partial image coincides with the position and / or shape of the ROI in the first partial image, and
• - Position- and / or shape-corrected partial images or sections thereof used to construct the result image.

This measure has the consequence that the individual partial images or sections thereof can be corrected out of themselves, ie from image information contained in them, so that the above-mentioned optical errors are compensated for in a result image constructed from them. The synchronization between reading and sample movement can therefore be based on be known or measured purely mechanical parameters. The image information parameters used for correction may include contrast, intensity, color and / or shape information. For example, certain markings on the substrate whose nominal values (eg position, shape, size, etc.) are known can be used as correction markers. Structures of the sample itself can also be used as correction markers. In particular, the structure of the illumination light, for example an intensity maximum of a laser beam, can also be used for the correction. As relevant excerpts of individual partial images, the ROIs in particular come into question. The reference image used to define the ROI may be the same as the first partial image or a separately captured image.

A particularly preferred application of the method according to the invention is in the range quality assurance, especially in the production of micro-arrays or biochips. It is preferably provided that with the detection of sample areas future Prepared to be detected sample areas be subjected to automated or visual inspection and in the case of deviations from predetermined setpoints Parameters of the sample preparation be varied accordingly. In the case of the production of micro-arrays or biochips, which is given here purely by way of example and in no way restrictive, For example, this can be done by adding substrates that be mechanically coated with patterns of biomolecules, comparatively short term after her preparation one for implementation the method according to the invention fed to suitable device become. The resulting result images can then be inspected by a human quality controller or automatically by using suitable image processing algorithms (e.g., pattern recognition algorithms) having predetermined setpoints (e.g. Shape, contrast, intensity etc.). Deviations from the setpoints on errors during sample preparation shut down. these can for those Samples being prepared be corrected manually or automatically. The success of Correction can then be checked shortly afterwards if then the test method according to the invention explained above for these samples is applied. The shorter the time interval between sample preparation and inspection is the lower the committee can be held.

is a correction of faulty samples due to the specific production process not possible or too costly, exists due to the described ellipsometric Analysis the possibility to determine a correction factor that is in the intended use considered the sample and thereby improve the quality of the results. In case of Micro-arrays could do this For example, the specification of a surface occupancy factor For example, in a fluorometric analysis as Weighting factor is received. An incompletely biomolecule-occupied element a micro-array would have accordingly e.g. a weighting factor between 0 and 1, while an oversized Element a weighting factor> 1 would be assigned.

• – die Steuermittel derart eingerichtet sind, dass der Detektor-Auslesebereich (12a) synchron zu der Bewegung der Probe (10) auslesbar ist, und
• – Bildverarbeitungsmittel vorgesehen und derart eingerichtet sind, dass nacheinander aus dem Detektor-Auslesebereich (12a) ausgelesene Ergebnis-Teilbilder (15a-15f, 15x, 15y) zu einem Ergebnisbild (14) zusammensetzbar sind.

The second object mentioned above is achieved in conjunction with the features of the preamble of claim 8, characterized in that

• - The control means are arranged such that the detector read-out area ( 12a ) in synchronism with the movement of the sample ( 10 ) is readable, and
• Image processing means are provided and are arranged such that successively from the detector read-out area ( 12a ) read result sub-images ( 15a - 15f . 15x . 15y ) to a result image ( 14 ) are composable.

to Avoiding repetitions will be regarding the effects and benefits of these measures to the effects and advantages of the corresponding ones discussed above Referred to procedural measures.

conveniently, a sensor is provided via which the control means information regarding the current positioning obtained the sample. Such information can be used to generate trigger signals for the Detector readout and thus for the synchronization of sample movement and detector readout be used. As sensors are optical, mechanical, magnetic and / or electrical sensors in question.

Prefers is the motorized sample carrier as a conveyor belt formed, which the sample perpendicular to the sample normal and move linearly parallel to the plane of incidence of the illumination light can be continuous or gradual. Such a conveyor belt, this is designed as a real band, but also as a grid, net, chain or the like can be, is particularly suitable for use in larger devices where samples are prepared in one area and in another area, with the help of the conveyor belt supplied be checked for quality.

at an alternative embodiment is the sample carrier formed as a rotation table, which normalizes the sample azimuthal to the sample can move and also continuously or step by step.

Conveniently, the Beleuchtungsa Arrangement beam shaping means to match the shape of the illumination light to the shape of the sample areas of interest. Adjacent sample areas, from which disturbing reflection light could be imaged on the same detector area, are not illuminated, so that no stray light can arise. Another advantage of this embodiment is that also the radiation load of the sample can be reduced or the achievable image contrast can be improved. Sample areas which are not focused on the detector at one time are also not illuminated, so that the illumination of the sample area of interest can be optimized, ie usually maximized, with respect to the achievable contrast, without others, possibly later to be measured Sample areas would be affected by the irradiation.

in the Case of a desired strip-shaped lighting this can be a cylindrical lens or a corresponding mirror optics, through which the illumination light onto a strip-shaped sample area is conductive, in particular perpendicular to the plane of incidence of the illumination light lies. As is known to those skilled in the field of optics, has a cylindrical lens or a corresponding mirror optics instead of a focal point on a focal line. It is therefore related with the device according to the invention suitable, the illuminated sample area on a narrow strip perpendicular to the direction of motion. Within this Can strip high intensities (and thus high image contrast) can be achieved without others Sample areas unnecessarily through Irradiation be charged. Usually forbids However, the use of cylindrical lenses or corresponding mirror optics for imaging. In combination with the sample movement according to the invention and the Synchronization with the detector readout, however, can take advantage of precise Lighting through the cylinder optics also in the context of an imaging Procedure be used.

Especially Cheap it is when the detector as a perpendicular to the direction of movement the sample is extended line detector, wherein a plurality of adjacent detector elements as a strip-shaped detector readout area are definable. Because namely due to the cylinder optics only a narrow strip illuminated can also be the corresponding detector readout area as a narrow strip be educated. The orientation of the line detector is preferred perpendicular to the deflection plane of the detection light or, in the case of Deflection optics in the detection arrangement, adjusted accordingly.

It but it is also possible the detector as area detector of which a perpendicular to the direction of movement of the Sample extending, strip-shaped Range of adjustable width or adjustable length and Width is defined as a detector readout range. For such Design results in significant relief regarding the focus of the system as well as advantages in the flexibility of the selection of the selection area. In addition, increased at simultaneous evaluation of several lines the sensitivity of the system by a correspondingly possible prolonged exposure time.

better Way, the cylinder optics is arranged such that the illumination light has a beam waist in the sample plane. This is special Cheap, if a laser beam with Gaussian beam profile is used as the source of the illumination light we, then in the sample plane, a substantially flat wavefront is realized.

Preferably it is provided that the lighting arrangement is a light source and arranged in front of the cylinder optics beam expansion means for Producing an expanded, parallel light beam. For example can be used as a light source, a laser whose narrow beam first through a radially symmetric beam expansion optics in both dimensions expanded perpendicular to the beam direction and then through the Cylinder optics is focused in one of these dimensions, while the Expansion in the other dimension is preserved. However, it is also possible, as Beam widening means to use another cylinder optics which expands the beam of the light source in only one dimension. This expansion is maintained by the focusing cylinder optics while vertical for this purpose the beam rejuvenation according to the invention takes place. In this case, the focusing cylinder optics preferably a long focal length.

at an advantageous embodiment The invention has the illumination arrangement polarization-influencing Light guide, e.g. a polarizer and a compensator, like about a quarter-wave plate, on the between the beam expander and the cylinder optics are arranged. In this way, the polarization properties of the illumination light to be set very precisely because subsequent disorders the polarization properties by the beam expansion optics excluded are. On the other hand, the polarization-influencing Elements in this embodiment a sufficiently large diameter have to let pass through the expanded beam. Polarisatorkristalle huge Diameter are relatively expensive.

In an alternative embodiment Therefore, it is provided that the illumination arrangement comprises polarization-influencing light-conducting means which are arranged between the light source and the beam widening means. These need only have a small diameter and are therefore relatively cheap. However, the subsequent beam expansion optics should then be selected very carefully to minimize the above-mentioned polarization property perturbations.

Further Features and advantages of the device according to the invention and of the method according to the invention result from the following specific description as well the drawings in which

1 1 shows a schematic sketch of the structure of a prior art imaging ellipsometer,

2 2 shows a schematic sketch of the detection beam path of a prior art ellipsometer,

3 FIG. 2 shows a schematic sketch of the detection beam path of an ellipsometer according to the invention, FIG.

4 schematically shows the structure according to the invention of a result image of partial result images and

5 shows the schematic structure of a particularly preferred embodiment of an ellipsometer according to the invention.

6 1 shows a schematic representation of the beam paths of an embodiment of an ellipsometer with cylindrical lens according to the invention,

7 a schematic top and side view of the illumination beam path of the ellipsometer of 6 shows,

8th shows a schematic representation of the superimposition of desired and interfering reflections of adjacent beams,

9 a schematic representation of a beam overlay upon incidence of a parallel beam and shows

10 shows a schematic representation of a beam overlay upon incidence of a beam with beam waist in the sample plane.

The basic structure of an ellipsometer was based on 1 already explained in the general part of this description. To avoid repetition, a re-description of 1 waived.

2 schematically illustrates the structure of the detection beam path of an ellipsometer according to the prior art. It should be noted that was omitted to simplify the figure to a representation of the polarization-relevant optical elements, such as an analyzer. Shown is a sample 10 of which reflected light by means of optics 11 on an imaging surface detector 12 is shown. Due to the angle φ at which the optical axis of the detection beam path is inclined relative to the sample normal, different regions of the sample have 10 different distances to the detector 12 , It is therefore not possible to use the imaging optics 11 while maintaining essential optical properties, such as the light intensity to be adjusted so that all areas of the sample 10 "Sharp" on the detector 12 be imaged. The known from the photograph Scheinflug'sche arrangement is only suitable for low magnifications, as for the frequently required high resolution and magnification extreme tilting of the detector and thus distortion of the image occurs. Usually one makes do with the fact that the imaging optics 11 initially adjusted so that a first sample area 10a on the assigned area 12a of the detector 12 is focused. With this setting, the remaining sample areas are "blurred" onto the other detector areas, which are used to read out a first image from the detector and then readjust the optics 11 (shown in phantom as imaging optics 11 ' so that a second sample area 10b to a second detector area 12b is shown sharply. Then again an image is read from the detector. This is done as often as necessary to focus all sample areas at least once sharply on a corresponding detector area. Afterwards, the respective "sharp" sections have to be cut out of the recorded sequence of single frames and put together to form a result picture.

As in 3 is shown schematically while maintaining the reference numerals, is provided according to the invention, after an initial adjustment of the imaging optics 11 such that a sample area 10a , the sample 10 "Sharp" on the corresponding detector area 12a no further adjustments are made to the imaging optics 11 be made. This can be optimized according to simple or with respect to other optical parameters than the adjustability or depth of field. After a single readout of the detector according to the invention, the sample 10 for example in the direction of the movement arrow 13 postponed, so that one the sample area 10a adjacent sample area "sharp" on the same detector area 12a is shown. Will the detector area 12a , where the "sharp image" is initially defined, cutting out the "sharp" portions of the resulting frames and assembling them into a larger area result image can be automated, and it is even better to have only the detector area recognized as a "sharp" image area read alone and to dispense with reading the remaining detector areas. This can speed up data acquisition and reduce the amount of data to be stored.

4 schematically represents the composition of a result image 14 from a plurality of sub-images 15a to 15f dar. The drawing files 15a to 15f each correspond to the from the "sharp" detector area 12a read data. In the exemplary embodiment shown, each partial image comprises only a single row of pixels. Of course, other definitions or partial image dimensions are possible.

In particular, when using the device according to the invention in a quality assurance device with visual monitoring, the result image 14 displayed immediately after its construction eg on a monitor. As in 4 Likewise indicated, the result image structure can be "continuous." Thus, each illustrated result image 14 each have the same dimensions, ie be composed of the same number of fields. The result picture 14 contributing submaps can, as in 4 in each case corresponding to those partial images which contributed to the structure of the preceding result image, but without the oldest partial image 15x and adds a recently added partial image 15y , In this way, the viewer gets the impression of a continuous result image 14 ,

5 shows a particularly favorable embodiment of an ellipsometer according to the invention. As a sample 10 schematically a so-called micro-array or a biochip is indicated. The detection beam path essentially corresponds to that in FIG 3 indicated beam path, which was omitted here to simplify the drawing on the representation of the polarization-relevant optical elements. As a special feature of in 5 illustrated embodiment is the detector 12 formed as a line detector. Of the illumination beam path of the ellipsometer is only an illumination optics 16 shown. Even in the illumination beam path has been dispensed with the representation of the polarization-relevant elements, such as polarizer and compensator and on the representation of the light source. As a special feature of in 5 illustrated embodiment is the illumination optics 16 represented as a cylindrical lens. An expanded parallel laser beam with Gaussian beam profile is preferably coupled into this cylindrical lens. Since the cylindrical lens has a focal line instead of a focal point, this arrangement leads to a strip-shaped illumination of the sample 10 , The illuminated sample area is as a sample area 10a shown. Conveniently, the cylindrical lens 16 so selected and arranged that, as in 5 indicated, the illumination beam in the sample plane having a beam waist. This leads to plane wavefronts in the sample plane and thus to a uniform distribution of the polarization properties of the illumination light. According to the invention, the sample, as by the movement arrow 13 indicated, moved by motor, so that successively lit all the sample areas and the detector 12 be imaged. As in 5 shown, the sample becomes 10 favorably moved perpendicular to the longitudinal extent of the strip-shaped illumination area.

6 represents the particularly favorable embodiment of an ellipsometer according to the invention with cylindrical lens of 5 The detection beam path, ie the elements between the light source 21 and the sample arrangement 45 are in 7 shown again, where 7a a plan view of the beam path shows and 7b a side view as in 6 , The light source 21 , which is preferably designed as a laser, emits an illumination beam 40 which preferably has a Gaussian beam profile. By means of a beam widening optical system, which in the embodiment shown consists of two cylindrical lenses 23 . 24 is constructed, the beam becomes 40 perpendicular to its plane of incidence on the substrate 50 (Paper level in 6 ) on widened (see 7a ). By means of an analyzer 25 and a compensator 26 are the polarization properties of the illumination beam 40 adjustable. Another cylindrical lens 27 which are perpendicular to the expansion lenses 23 . 24 aligned, focuses the illumination beam 40 to the test, preferably so that it forms a beam waist in the sample plane. This leads to a strip-like illumination of the sample, as in the rectangular field in FIG 6 indicated, which is a schematic plan view of the sample arrangement 50 represents. The reflected light 40 ' is by means of an imaging optics 28 , which may have a common radial symmetry, to an imaging detector 30 displayed. For performing ellipsometric measurements is also in the detection beam path an analyzer 29 arranged. The motion arrow 60 indicates the sample movement according to the invention synchronized with the reading of the detector.

8th poses the problem of the superposition of neighboring beams, with large areas This problem can be circumvented by the illumination described above by means of cylindrical lens. The sample arrangement, of which in 8th only a transparent carrier substrate 50 is shown with a lighting beam 40 illuminated, which illuminates a large sample area in parallel according to conventional technology. In 8th are from the lighting bundle 40 adjacent parallel partial beams 41 . 42 . 43 . 44 . 45 shown. A part of every ray 41 - 45 is on an upper surface 51 of the substrate 50 (or on the actual sample, if this, for example as a thin biomolecule layer, on the surface 51 applied) directly as a reflection beam 41 ' - 45 ' reflected in the direction of the detector. Another part of each ray 41 - 45 penetrates the upper surface 51 of the substrate 50 and gets to the bottom surface 52 of the substrate 50 (or on the actual sample, if this on the surface 52 is applied) ( 41 '' - 45 '' ). After renewed passage through the upper surface 51 of the substrate 50 this light runs as indirectly reflected rays 41 ''' - 45 ''' also to the detector too. At the same time the indirectly reflected rays are superimposed 41 ''' - 45 ''' with the respective adjacent directly reflected rays 41 ' - 45 ' , On the detector, the overlapping steels fall onto the same detector elements so that they contribute indistinguishably to the resulting signal. Depending on which of the surfaces 51 . 52 of the substrate 50 the sample layer to be measured is applied, the directly reflected parts must 41 ' - 45 ' or the indirectly reflected shares 41 ''' - 45 ''' be regarded as a desired signal or as a noise component.

9 shows the case that the transparent carrier substrate 50 is formed so thin that, despite inventive lighting on a cylinder optics, an overlap area 46 results in the directly and indirectly reflected light incident on the same detector elements, although in other areas a clear separation is possible. The overlap area 46 is in 9 hatched shown. 9 assumes the case that the illumination of the sample takes place with a substantially parallel light beam.

10 shows the case of particularly advantageous illumination of the sample with a beam of light with a pronounced beam waist in the sample plane. Such lighting can be, for example, with the arrangement of 6 realize. By the expansion of a beam, in particular with Gaussian beam profile, and subsequent focusing in the sample plane by means of a cylindrical lens, an effective beam taper in one dimension in the sample plane can be achieved. This has the effect that there is no overlap of directly and indirectly reflected light in the sample plane. The hatched area of overlap 37 is, on the other hand, harmless, since the beams overlapping one another here have different directions, so that they can be separated from the imaging optics and directed to different areas of the detector.

Of course they are those shown in the figures and in the special part of Description explained embodiments the invention merely illustrative examples. In particular with regard to the concrete sequence of measurement and evaluation steps and the concrete design of the individual components of the device according to the invention the expert has a wide range of possible variations to disposal.

Claims (20)

Method for the imaging, ellipsometric detection of a mainly flat extended sample arrangement ( 10 ), in which - the sample arrangement is illuminated at least in regions by means of a lighting arrangement with illumination light of adjustable polarization properties under an illumination angle (φ) inclined to the sample normal, - of illuminated areas of the sample ( 10 ) reflected detection light in a under a suitable, normal to the sample normal inclined illumination angle (φ) arranged, polarization-sensitive detection arrangement on a controlled readable detector ( 12 ) is imaged with a plurality of ordered, photosensitive detector elements, - the sample arrangement ( 10 ) is moved by a motor relative to the detection arrangement, and - at least one detector read-out area ( 12a ), on the successively different sample areas ( 10a ; 10b ), is read in time correlation with the movement of the sample arrangement for generating images representing sample areas - characterized in that - the detector read-out area ( 12a ) in synchronism with the movement of the sample ( 10 ), and - one after the other from the detector read-out area ( 12a ) read result sub-images ( 15a - 15f . 15x . 15y ) to a result image ( 14 ). Method according to claim 1, characterized in that the sample ( 10 ) is moved linearly perpendicular to the sample normal and parallel to the plane of incidence of the illumination light, namely continuously or stepwise. Method according to one of the preceding claims, characterized in that the polarization properties of the illumination light and polarization-sensitive elements (A) of the detection Anord tion at the beginning of a process section relative to each other are set such that a result image of a reference sample arrangement with respect to at least one image characteristic value shows an extreme value. Method according to claim 3, characterized the relevant image characteristic is a contrast between two selected sample regions. Method according to one of the preceding claims, characterized in that a result image constructed from result partial images each of the previously constructed result image without the first read out Result field and added to a newly read result sub-picture corresponds. Method according to one of the preceding claims, characterized marked that - in a reference image based on image information parameters a region of interest (ROI: region of interest) and their position and / or Shape is determined in a first field, - in one second sub-picture the position and / or shape of the ROI based on the same Image information parameter is determined - the second field at least partially by translation, rotation, compression and / or extension is corrected so that the position and / or shape of the ROI in the second partial image with the position and / or shape of the ROI in matches the first part, and - positional and / or shape-corrected partial images or sections thereof for construction of the result image. Method according to one of the preceding claims, characterized characterized in that with the detection of sample areas in the future too prepared sample areas be subjected to automated or visual inspection and in the case of deviations from predetermined setpoints Parameters of the sample preparation be varied accordingly. Imaging ellipsometer for imaging, ellipsometric detection of a mainly flat extended sample ( 10 ), comprising - a lighting arrangement for at least partial illumination of the sample ( 10 ) with illumination light of selectable polarization properties under an illumination angle (φ) inclined to the sample normal, a detection arrangement arranged below a suitable detection angle (φ) inclined to the sample normal for the polarization-sensitive, imaging detection of detection light, which differs from illuminated areas of the sample ( 10 ), comprising a controlled readable detector ( 12 ) with a plurality of photosensitive, ordered detector elements, - a movable sample carrier, with which the sample is movable, so that different sample areas on the same detector read-out area ( 12a ), control means for controlling the reading out of at least one detector read-out area ( 12a ), on which successively different sample areas are imaged, in a time-correlated manner to the movement of the sample, characterized in that - the control means are set up in such a way that the detector read-out area ( 12a ) in synchronism with the movement of the sample ( 10 ), and - image processing means are provided and are set up such that successively from the detector read-out region ( 12a ) read result sub-images ( 15a - 15f . 15x . 15y ) to a result image ( 14 ) are composable. Ellipsometer according to claim 8, characterized that at least one sensor is provided, via which the control means Information regarding the current one. Positioning of the sample obtained. Ellipsometer according to one of claims 8 or 9, characterized that the motorized sample carrier as a conveyor belt is formed, which the sample perpendicular to the sample normal and move linearly parallel to the plane of incidence of the illumination light can be continuous or gradual. Ellipsometer according to one of claims 8 or 9, characterized in that the motor-movable sample carrier as Rotation table is formed, which is the sample azimuthal to the sample normal can move, either continuously or step by step. Ellipsometer according to one of claims 8 to 11, characterized in that the illumination arrangement beam shaping means for the proper lighting of interest sample areas includes. Ellipsometer according to claim 12, characterized in that the illumination arrangement is a cylindrical lens ( 16 ; 27 ) or a corresponding mirror optics, by means of which the illumination light is directed onto a strip-shaped sample area ( 10a ) is conductive. Ellipsometer according to one of claims 8 to 13, characterized in that the detector ( 12 ; 30 ) is formed as a perpendicular to the direction of movement of the sample extended line detector, in which a plurality of adjacent detectors elements as a strip-shaped detector readout region ( 12a ) are definable. Ellipsometer according to one of claims 13 or 14, characterized in that the cylinder optics ( 27 ) is arranged such that the illumination light ( 40 ) has a beam waist in the sample plane. Ellipsometer according to one of claims 13 or 15, characterized in that the illumination arrangement is a light source ( 21 ) and arranged in front of the cylinder optics beam expansion means ( 23 . 24 ) for generating a widened, parallel light beam. Ellipsometer according to one of claims 13 or 16, characterized in that the illumination arrangement polarization-influencing light guide ( 25 . 26 ), which between the beam widening means ( 23 . 24 ) and the cylinder optics ( 27 ) are arranged. Ellipsometer according to one of claims 13 or 17, characterized in that the illumination arrangement polarization-influencing light guide ( 25 . 26 ) located between the light source ( 21 ) and the beam widening means ( 23 . 24 ) are arranged. Ellipsometer according to one of claims 8 to 18, characterized in that the detector is designed as an area detector, of which a sample area of interest corresponds Detector selectable range is definable. Quality assurance module for detecting manufacturing defects in a product manufacturing device comprising an ellipsometer according to one of claims 8 to 19 and suitable for execution A method according to any one of claims 1 to 7.