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WO2010094658A1 - Contrôle de miroirs pivotants - Google Patents

Contrôle de miroirs pivotants Download PDF

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Publication number
WO2010094658A1
WO2010094658A1 PCT/EP2010/051876 EP2010051876W WO2010094658A1 WO 2010094658 A1 WO2010094658 A1 WO 2010094658A1 EP 2010051876 W EP2010051876 W EP 2010051876W WO 2010094658 A1 WO2010094658 A1 WO 2010094658A1
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WO
WIPO (PCT)
Prior art keywords
pattern
mirror
light
mirrors
detection
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2010/051876
Other languages
German (de)
English (en)
Inventor
Jan Horn
András G. MAJOR
Christian Kempter
Ulrich Bihr
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Carl Zeiss SMT GmbH
Original Assignee
Carl Zeiss SMT GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Carl Zeiss SMT GmbH filed Critical Carl Zeiss SMT GmbH
Publication of WO2010094658A1 publication Critical patent/WO2010094658A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
    • G03F7/7085—Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
    • G02B26/0833—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70058—Mask illumination systems
    • G03F7/70091—Illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane; On-axis or off-axis settings, e.g. annular, dipole or quadrupole settings; Partial coherence control, i.e. sigma or numerical aperture [NA]
    • G03F7/70116—Off-axis setting using a programmable means, e.g. liquid crystal display [LCD], digital micromirror device [DMD] or pupil facets
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70425—Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating lithography- or non-lithography errors, e.g. proximity correction, mix-and-match, stitching or double patterning

Definitions

  • the present invention relates to a device and a method for monitoring or determining the orientation or positioning of at least one mirror, in particular a plurality of mirrors with a detection device for detecting the reflected light from the mirror or mirrors and a projection exposure apparatus in which such a device and a corresponding method can be used.
  • microlithography projection exposure systems systems requiring light wavelengths in the vacuum ultraviolet (VUV) or extreme ultraviolet (EUV) range are being increasingly developed due to the required resolution of increasingly smaller structures.
  • VUV vacuum ultraviolet
  • EUV extreme ultraviolet
  • These systems contemplate the use of so-called Micro Mirror Arrays MMA's (Micro Mirror Panels) having a plurality of small tiltable mirrors with a number of up to several million mirrors for setting flexible illumination.
  • Micromechanical or microelectromechanical units with adjustable mirrors are also used in projection exposure systems which use other wavelengths of light.
  • the required measurement time plays an essential role for the effective monitoring of the mirror positions in order to be able to form rapidly switchable and dynamic systems.
  • the device and the corresponding method should ensure sufficient accuracy of the position detection.
  • the present invention is unlike the previous approaches, which perform only an analysis and evaluation of the reflected light to determine the position of the mirror, to provide already on the lighting side no homogeneous illumination of the mirror or mirrors, but to provide a pattern which or the mirror is imaged into a corresponding detection device.
  • the pattern can be spatial and / or temporally variable light sources, so that in particular with knowledge of the original pattern, a comparison of the mirrored light with the original pattern and / or the detection and evaluation of the light reflected on the mirrors or the light of the pattern allows conclusions about the orientation of the mirror.
  • the pattern source providing the corresponding pattern can be realized in different ways.
  • the pattern is printed on a sheet of paper or other support, such as a screen, or displayed on a screen or monitor, such as a TFT screen or the like.
  • a plurality of individual separate bulbs in a corresponding arrangement produce a pattern.
  • LED arrays light emitting diode arrays
  • the pattern may be formed by active light sources and / or by passive light sources, in which illumination light is reflected only correspondingly.
  • the term light source is any single point of a surface-extending pattern which emits light to be reflected on the mirror (s) to be monitored.
  • the emitted light intensity can also drop to or at least near a zero value, so that no light is reflected.
  • the term light is generally used as a term for electromagnetic radiation.
  • the patterns used in the present invention have different light sources over the pattern surface, so that correspondingly spatially variable or different light sources result, which ultimately produce the corresponding pattern.
  • the basic principle of the present invention is that due to the given pattern corresponding to the mirror position different, mirrored images or Light intensities of the mirrored pattern in a detection device for detecting the reflected light from the mirror are detectable. Due to the dependence of the detected, reflected by the mirror light from the mirror position, can be deduced in particular with knowledge of the output pattern on the mirror position. Alternatively, a corresponding pattern also gives the possibility to monitor mirror movements based on changes in the detected light and to deduce the position and / or orientation of the mirror from the tracking of the mirror movement. By mirroring a pattern, the evaluation of the reflected light becomes easier or more effective and the position and / or orientation of the mirror can be more accurately determined compared to homogeneous illumination methods.
  • position, orientation and orientation are used interchangeably and generally define that the unique three-dimensional determination of the arrangement at a maximum of 6 degrees of freedom of movement is meant.
  • degrees of freedom of movement for example the possibility of tilting only about one axis, only the tilt angle is accordingly meant, so that this too is used interchangeably for position and orientation.
  • a corresponding evaluation unit in particular a plurality of automated evaluation units, preferably based on electronic data processing, can be provided for the analysis or evaluation of the reflected light, which information is acquired from the information about the original pattern to be mirrored and / or the information collected by the detection device , reflected light can determine an absolute or relative position of the mirror or mirrors.
  • the detection device can be formed by or include various devices, such as one or more black-and-white cameras with or without color filters, one or more color cameras or sensors based on these digital cameras, such as charge coupled device CCDs, CMOS (Complementary metal oxide semiconductor) sensors (complementary metal oxide semiconductor sensors) or photodiodes in general.
  • CCDs charge coupled device
  • CMOS Complementary metal oxide semiconductor
  • sensors complementary metal oxide semiconductor sensors
  • photodiodes in general.
  • the selection of a corresponding detection device depends on the exact configuration of the corresponding measuring device and the measuring method.
  • the pattern-based monitoring method or system can be configured so that only the light intensities differ.
  • the light sources of the pattern with respect to one or more specific mirrors are evaluated to determine an absolute position of the mirror or mirrors.
  • the detection device for example in the form of a camera, may have an optical system that is prepared so that the mirror or mirrors to be monitored are imaged sharply into the image area of the detection device, ie the camera is focused on the mirrors. Accordingly, the defined image from mirror to detection device is achieved, in particular, by focusing a camera on the mirrors so that the mirror or mirrors are clearly imaged in the detection device. This ensures that each mirror is assigned a defined image area of the camera.
  • one or more pixels of a corresponding image sensor defined are associated with a mirror of, for example, a plurality of mirrors of a mirror field.
  • the corresponding absolute position of the mirror can be determined. For example, a plurality of light sources of a pattern area, which is mirrored by a mirror onto a defined image area of the detection device, can illuminate successively. This means that the spatially different light sources of the pattern with constant mirror orientation in the predetermined image area of the detection device generate different light intensities due to the different geometrical conditions, even if the spatially different light sources have the same light intensities. From these measured values, the orientation of the mirror can then be determined at least with respect to the tilt about two axes of rotation.
  • spatially different light sources with the same wavelength of light or same wavelength range and same or different radiation intensity which are only switched sequentially, find a pattern in which are used as spatially different light sources with different wavelengths of light or wavelength ranges.
  • light-emitting diodes can be used in a light-emitting diode array which emit light in the green light wavelength range, in the blue light wavelength range and in the red light wavelength range.
  • the corresponding intensities in the detection device can be determined for the differently colored light sources, so that again distinguishable measured values are present.
  • they can be for the locally different light sources determine the data collected by the detection device for the reflected light and thus calculate the mirror position.
  • a direct pattern matching can also take place.
  • a detection device such as a camera, can be set with the corresponding optics so that the pattern can be sharply imaged.
  • the detection device may be configured such that only one detection point of the detection device, that is, for example, a pixel of the camera, is assigned to a mirror, so that the detection point for the respective mirror detects the reflected light.
  • the presented monitoring system is well suited for monitoring a plurality of mirrors, since the number of mirrors to be monitored is limited only by the number of pixels of the detector or in a simple manner, a high number of mirrors can be monitored.
  • the term pixel will be used interchangeably for a corresponding detection point of the detection device.
  • each mirror it is also possible for each mirror to have a plurality of pixels associated with the detection device, for example at least 9 pixels, preferably at least 16 pixels or most preferably 25 pixels.
  • the corresponding resolution can be increased or certain patterns or pattern matching methods can be used.
  • the patterns provided by the pattern source and the corresponding pattern matching methods may be of different types.
  • the patterns can have light sources with light of different wavelengths or wavelength ranges or light sources with light of the same wavelengths of light.
  • the corresponding light sources may be associated with certain positions in the pattern or evenly distributed throughout the pattern.
  • the radiation intensity of the light sources can vary over the pattern, with continuous or stepwise variation of the intensity being possible.
  • the light sources can also be combined into corresponding groups together and in this case arranged in a sectoral manner in the pattern.
  • a periodic, grid-like arrangement is conceivable. With a periodic arrangement of the light sources, an arrangement in accordance with a sine wave can be provided.
  • the corresponding design of the pattern with regard to the light intensity may relate to light sources with light of a single wavelength of light or of a range of light wavelengths (white light) or may be provided in each case for light sources of different wavelengths of light or wavelengths of light.
  • the changes of the pattern along the x and y directions of the pattern surface can be provided for one light wavelength or one light wavelength range, respectively.
  • the light intensity of a first wavelength for example in the red frequency range
  • a second wavelength range for example of green light
  • the change here can be either a continuous or incremental increase or decrease in the light intensity or a periodic change, such as corresponding to a standing sine wave.
  • a periodic change such as corresponding to a standing sine wave.
  • corresponding patterns that vary with time can also be used to realize corresponding waves that propagate through the pattern.
  • phase-measuring deflectometry in which the phase of a periodic pattern, for example a sinusoidal or cosinusoidal intensity or brightness curve, in connection with the local and / or or temporal variation of the pattern is used to infer the angle of reflection and thus the orientation and orientation of a mirror used to mirror the pattern.
  • the principle here is based on the fact that, depending on the tilt angle of the mirror, there is another reflection angle below which a region of the pattern is imaged in a detection device, for example a camera.
  • a temporal and / or local change of the pattern or of the detection device in the case of a plurality of measured values (acquisitions) or images in which the reflected pattern is detected, it is possible to calculate back what tilt orientation of the mirror is present.
  • a one-dimensional periodic gray scale profile for example in a sine or cosine form, is sufficient. This can be generated in the pattern, for example by a TFT screen, first as an X-directional wave to determine an orientation or tilt of the mirror in the X direction, and then the periodic pattern in the Y direction can be displayed to determine a tilt in the Y direction.
  • a two-dimensional phase-measuring deflectometry can be applied, in which, for example, a gray scale profile is present, in each case a sine wave or cosine patterns in the X and Y directions are superposed with each other.
  • the periodic patterns such as sine and cosine curves
  • the periodic patterns can also be generated with different wavelengths of light, so that, for example, in the X direction periodic pattern with green light and in Y-direction a periodic pattern with red light is generated.
  • a second parameter can be selected that covers the different phases in the second spatial direction , that represents the y-direction.
  • the parameters in a suitable manner. For example, it is advantageous to select the number of images (acquisitions) higher than the minimum value in order to compensate for deviations introduced during the measurements due to inaccuracies in the pattern or the detection device.
  • a multiplier ie in particular in the range less than or equal to 10 or less than or equal to 3.
  • the theoretical minimum of the acquisitions is three images, for example, 4, 6, 8 or 12 images could be selected.
  • a larger number of images such as 8, 10, 16, or the like could be selected.
  • the second parameter can then be selected as a fraction of the first parameter, the value of the first parameter being present in the numerator and a corresponding integer in the denominator.
  • phase deconvolution may also be used, in which a plurality of periodic patterns, for example cosine patterns, are superimposed.
  • the phase-measuring deflectometry can also be used if the pattern is fixed in time, ie no corresponding wave runs over the pattern surface.
  • a temporally invariable pattern can be used, which in turn has a one-dimensional or two-dimensional periodic pattern, but this time fixed.
  • a plurality of locally differently arranged detection means are used, so that the different detection means the different phases in different areas of the periodic pattern can be detected according to the orientation of the mirror.
  • phase-shifting patterns can also be effected by the sequentially switched and / or superimposed representation of patterns.
  • overlaid patterns that are not self-variable in time, e.g. suitable overlays of slide projections or the like can be used to generate corresponding phase-shifting patterns.
  • the corresponding patterns can also be imaged, for example, with different colors firmly on a substrate and switched by irradiation with special light, such as complementary colors, polarized light or the like.
  • corresponding patterns with corresponding illuminant fields that is to say a number of lamps, in particular LEDs or the like, which can generate a phase characteristic by suitable switching of corresponding groups of the luminous means.
  • Another possibility is to illuminate a grid or a perforated plate or mask with a plurality of light sources, so that a corresponding pattern is formed on a diffuser arranged in front of the perforated plate or the grating or mask. By appropriate Switching the different light sources can then be generated on the diffuser again a phase-shifting pattern.
  • the method can be refined accordingly, so that the ambiguity of a phase determination can be resolved via the color code and can be used, for example, for the coarse determination of the positioning of the mirror.
  • a pattern generating device can have a plurality of light sources with masks assigned to each light source, wherein the masks have corresponding patterns that are imaged by the light sources and any optics onto a projection screen or luminescent screen. Due to the superimposition and / or successive switching of the different patterns, correspondingly time-varying patterns can be generated on the projection screen or fluorescent screen.
  • Such an arrangement may be particularly advantageous in projection exposure equipment in which the pattern should be placed in a vacuum chamber, since the generation of the pattern in a vacuum could be problematic and mirroring of an externally applied pattern through vacuum partitions is difficult to achieve.
  • the optics or parts thereof may be provided in the vacuum chamber partition so that the pattern per se with the projection screen is simply provided in the vacuum chamber can and mirror elements in vacuum chambers can be measured accordingly.
  • binary masks can also be used in connection with defocused imaging optics in order to generate patterns with, for example, sinusoidal or cosinusoidal progressions.
  • the position of the mirror is determined by monitoring the change in the mirror position, in which the displacement of the periodic pattern associated with mirror tilting in the detector is determined on the basis of the passing periods. telt.
  • the absolute positions may also be determined by such methods.
  • the pattern may also be an arbitrary noise pattern or a randomly generated pattern, in particular for the second embodiment variant with a pattern recognition, such as surface areas of components in the vicinity of the mirrors to be monitored, e.g. painted or textured surfaces of the housing of a projection exposure system or the like.
  • adjacent groups can be switched so that they are not switched simultaneously in order to avoid mutual interference or interference.
  • additional illumination in particular only temporary illumination for the time of the measurement acquisition, e.g. be provided by flashing lights or the like.
  • the patterns can also be imaged by imaging devices in the vicinity of the mirror to be monitored, if this makes it necessary, for example, lack of space.
  • d. H The comparison of the pattern imaged in the detection device with the original pattern can be carried out using different methods of image or pattern recognition or comparable methods, in particular correlative methods.
  • a gradient-based motion estimation can also be used for the measurement, that is to say for comparison of the mapped and original pattern, eg. When using noise patterns.
  • Gradient-based motion estimation is described in addition to correlative methods eg in Jahne: Digital Image Processing, 4th Edition, Chapter 13, Springer Verlag.
  • a translatory movement or an offset of the mirrors can lead to a measurement error that can be compensated by a second camera.
  • the curvature of the mirrors can also be used to compensate for such translatory movements.
  • a simple thought model is, for example, the modeling of a curved mirror as two plane mirrors at a fixed angle to each other. For both plane mirrors, the tilt angles can now be determined in each case except for a translational ambiguity. The fixed and known position of the two mirrors can be used, for example, to resolve the translational ambiguities.
  • This idea model can be extended if a curved mirror is modeled as a concatenation of many tilted plane mirrors.
  • the arrangement according to the first embodiment variant of the invention can be provided in the form of an inverted beam path, such that a translatory movement or an offset of the mirrors, in particular perpendicular to the mirror surface (z offset) is automatically compensated.
  • the method and the device for monitoring or for monitoring a first multiple mirror arrangement can be used, which are arranged in a field level of a lighting system as field facets. These direct the light onto a second multi-mirror arrangement in a pupil plane, the so-called pupil facets or a field-defining element (field-defining element FDE). If now the monitoring device with the pattern instead of the pupil facets and the detection device, for example in the form of the camera, instead of the virtual light source, then corresponding translational movements of the first multiple mirror array (field facets) are automatically compensated.
  • the device for monitoring the mirrors is of course not arranged in the same plane of the beam path as the working light, but tilted about the optical axis, in particular by 90 °, so that no disturbance of the working light beam path takes place.
  • the pattern to be mirrored may also have a structure that corresponds to the structure of the pupil facets, for example with regard to the arrangement of the light sources.
  • Figure 1 is a perspective view of a structure of an apparatus for monitoring tiltable mirror according to the invention
  • Figure 2 is a plan view of a fiction, contemporary arrangement for monitoring tiltable mirrors that can be used in a projection exposure;
  • FIG. 3 shows a part of a lighting system of a projection exposure apparatus
  • Figure 4 is an illustration of a projection exposure system in which a corresponding monitoring system is used
  • Figure 5 shows the representation of a pattern for use in the inventive method and the inventive device
  • Figure 6 is an illustration of another pattern for use in the method and apparatus of the invention.
  • FIG. 7 is an illustration of the mirrored pattern of FIG. 6;
  • FIG. 8 shows a detailed representation of the mirrored image from FIG. 7 for the green channel;
  • FIG. 9 shows a detailed representation of the mirrored image from FIG. 7 for the red channel
  • FIG. 10 shows a further example of a sample for use in the method according to the invention and the device according to the invention.
  • FIG. 11 is an illustration of the mirrored pattern of Figure 10
  • FIG. 12 shows an illustration of a time-varying pattern with four successive partial images for measuring the tilting of a mirror in the x direction;
  • FIG. 13 is an illustration of a time-varying pattern according to FIG. 12 for measuring the tilt in the y-direction;
  • Figure 14 is a representation of the operation of a mirror tilt on the detected imaging range of the pattern;
  • FIG. 15 shows a further illustration of a time-varying pattern with a sinusoidal or cosinusoidal pattern in the x direction at three successive points in time;
  • 16 shows an illustration of an arrangement for phase-measuring deflectometry with a time-invariant, two-dimensionally periodic, in particular sinusoidal or cosinusoidal, pattern with a plurality of detection devices (cameras);
  • FIG. 17 shows the illustration of the pattern from FIG. 16 with the detection areas of the individual cameras
  • FIG. 18 shows an alternative embodiment to the arrangement from FIG. 16 with only one detection device and a plurality of detection regions of the detection device;
  • FIG. 19 shows an arrangement for producing a pattern on a projection screen using a plurality of transmission masks
  • FIG. 20 is an illustration of the control of the individual light sources in the arrangement of FIG. 19 for generating a pattern superimposed on the subpatterns of the individual masks;
  • FIG. 21 is an illustration of the operation of binary masks
  • FIG. 22 shows an illustration of a lamp arrangement for producing a two-dimensional pattern with 17 lamps for 5 evaluation images in partial image a) and 29 lamps for 8 evaluation images in partial image b);
  • FIG. 23 shows a representation of a further pattern generation device.
  • FIG. 1 shows a first embodiment of an arrangement according to the invention for monitoring tiltable mirrors.
  • the arrangement comprises a camera 1 which captures an image detail 5 of a pattern 3 which is imaged via one or more mirrors 4 of a so-called mirror array (mirror field).
  • the pattern 3 can be realized in different ways, as will be described in more detail below.
  • the pattern 3 can be displayed on any screen 2, printed on paper, on a monitor, a surrounding housing or otherwise. It only matters that the area of the pattern 3 spanned in accordance with the coordinate system x s and y s represents a multiplicity of light sources, which results in at least one image detail 5 being reflected in the direction of the detection device (camera 1) via the mirrors 4 so that the camera 1 can detect the light of the plurality of light sources of the pattern 3.
  • the camera 1 can be a digital camera according to CCD or CMOS technology, which is capable of taking corresponding pictures at a specific frequency, wherein the picture rate also determines the temporal sampling rate of the measurement.
  • the image or sensor data ascertained with the camera 1 are transmitted via an appropriate data line 8 to an evaluation unit 7, which determines the orientation of the mirrors 4 of the mirror array by comparing the image determined with the camera 1 on the basis of the knowledge of the pattern 3 6 can perform.
  • the evaluation unit 7 can perform image recognition by corresponding pattern matching, so that the orientation and orientation of a corresponding mirror 4 can be determined by finding the image detail 5 of the pattern 3 recorded in the camera 1 for the mirror 4.
  • the corresponding assignment of the imaged pattern to the individual mirror must also take place. This could be done, for example, by the camera 1 only ever detecting only a single mirror 4 and sequentially detecting all the mirrors 4 of the mirror array 6.
  • the camera optics of the camera 1 be chosen so that a corresponding depth of field can be achieved, in which both the mirrored pattern 3 and the mirror are detected sharp.
  • a defined area is assigned to each mirror in the image of the camera 1, although different image sections of the mirrored pattern 3 are present depending on the tilt orientation of the corresponding mirror in the assigned image area.
  • the optics of the camera 1 can also be focused on a region between the pattern 3 or the screen 2 and the mirrors 4. If each individual mirror 4 is detected individually by the camera 1, it is possible to focus on the pattern 3 or the screen 2, thus providing a good resolution for the pattern recognition, ie for the comparison between the pattern picked up by the camera 1 and the screen 2 originally produced pattern 3 to be obtained, which is carried out in the evaluation unit 7.
  • This variant of the monitoring is advantageous due to the possibility of using any desired pattern, wherein it merely has to be ensured that the pattern does not repeat periodically, so that ambiguities arise, or that these are taken into account in the evaluation.
  • Focusing the camera 1 on the pattern 3, d. H. a sharp image of the mirror image of the pattern in the image region of the detection device, can also be made if the mirror 4 have a sufficient distance or there is no overlap of the corresponding image areas for each mirror in the camera image.
  • the pattern 30 is formed by a plurality of light sources, e.g. Example, by an LED array (a field of light-emitting diodes) 20 or a corresponding representation on a monitor or the like.
  • the pattern 30 is reflected via a mirror array 60 with individual mirrors 40 in the direction of a camera 10, the camera 10 in the present case being focused on all the mirrors 40 of the mirror array 60, so that each mirror 40 of the mirror array 60 has an image area in it associated with the camera 10.
  • a multiplicity of micro mirrors in extreme cases one pixel each of the corresponding sensor of the camera 10 can be associated with a mirror 40 of the mirror array.
  • the orientation of the respective mirror 40 from the light intensities measured by the camera 10 can be determined from various measurements. If, for example, the LED light sources 31 forming the pattern 30 are activated individually or in groups one after the other, so that light radiation is generated at different locations of the pattern 30, which is mirrored into the detection device via a common mirror, then at least three measurements can be made per mirror the absolute orientation of the mirror can be determined. Due to the temporally and spatially variable light intensity of the pattern 30, d. H. with differently connected LED light sources at different measuring times, the orientation of the corresponding mirror 40 can be determined.
  • the light-emitting diode array 20 may be configured such that a plurality of groups of LEDs are arranged in rows and columns next to each other, each group of LEDs being arranged for imaging through a single mirror in a square, which are switched one after the other.
  • LEDs can be used which emit light with the same wavelength or a similar wavelength range, and as a camera 10 can serve a black and white camera.
  • Acceleration of the measurement can be achieved by using light emitting diodes emitting light of different wavelengths.
  • the reflected light of differently colored and locally distributed LEDs 31 can be separated from the light emitting diode array 20 of the camera with only one measurement per mirror and according to the different mirror conditions of light with different wavelengths Orientation of the corresponding mirror can be determined.
  • an overlap of several light emitting diodes for a given mirror may occur, ie the light of several adjacent groups of light emitting diodes is reflected by a mirror.
  • the groups can also be operated separately, for example in the manner of a checkerboard pattern, so that no adjacent groups are operated simultaneously and interfere with each other.
  • Such a construction of a corresponding monitoring system can in particular be designed such that it represents an inverted beam path of a beam path of an illumination system in a projection exposure apparatus, in particular an EUV illumination system of an EUV projection exposure apparatus.
  • FIG. 3 shows a portion of an EUV illumination system in which the light of a light source 100 is applied to a mirror assembly 110 in a field plane, i. H. on so-called field facets, on a multi-mirror arrangement 120 in a pupil plane, the so-called pupil facets, is directed.
  • a continuous surface of a so-called Field Defining Element FDE field-shaping element
  • the mirror assembly 110 will now be monitored or measured according to the invention so that the mirror assembly 110 corresponds to the mirror assembly 60 of FIG.
  • the LEDs 31 of the LED array 20 may be distributed or grouped according to the arrangement of the pupil facets 120. By increasing the number of light-emitting diodes per group, the measurement accuracy can be increased, but when using light-emitting diodes of the same wavelength by the Nacheinan-betuschigen the individual LEDs, the measurement time is extended.
  • a periodic arrangement for. B. a square or hexagonal grid can be provided.
  • FIG. 4 shows how corresponding arrangements according to the invention for monitoring tiltable mirrors, as shown in FIGS. 1 and 2, can be used in a projection exposure apparatus.
  • the projection exposure apparatus 150 in the embodiment of an EUV projection exposure apparatus comprises a light shaping unit 151, an illumination system 152 and a projection objective 154.
  • the light from the light shaping unit 151 which is shown schematically as a beam path in FIG. 4, is applied to field facets of the illumination system 152, for example Directed multiple mirror array 110, which reflect the light on pupil facets of a multi-mirror assembly 120.
  • a reticle 153 is illuminated and the reflected light is directed onto the substrate 155 in the projection objective 154, so that the structure contained in the reticle 153 is reduced in size on the substrate 155.
  • FIGS. 2 and 20 schematically show the screen or the light-emitting diode array of a pattern source adjacent to the multi-mirror arrangement 110 to be monitored, the beam path of the monitoring system being perpendicular to the image plane, while the beam path of the working light of the illumination system 152 is substantially in the image plane , So that the two beam paths are tilted by about 90 ° to each other and thus no mutual interference occurs.
  • the ring system outside the beam path of the working light of the illumination system 152 ensures that the monitoring system does not disturb the projection exposure apparatus 150.
  • FIG. 5 shows a first embodiment of a pattern in which a square area is designed in such a way that the intensity of the light of a first wavelength, for example light in the red wavelength range, increases in a Cartesian coordinate system in the x-direction, while along the second coordinate axis of the Cartesian coordinate system, ie the y-direction increases the intensity of the light of a second wavelength, so for example light in the green wavelength range.
  • a different light source results for each point, which differs in its red or green component.
  • a strong red intensity and a strong green intensity while in the diagonally opposite corner only a low green intensity and a low red intensity are observed.
  • the pattern of FIG. 5 stored in the evaluation unit 7 can be used are compared with the image section 5 shown by the respective mirror 4 and a clear assignment of the image section 5, which is mirrored by a corresponding mirror 4 in the image of the camera 1, are made.
  • the red-green pattern can additionally be configured as an RGB pattern with a blue component, the blue component being uniformly distributed uniformly over the surface in order to be able to determine illumination inhomogeneities with this blue component as the third color component by means of a corresponding normalization and to be able to account for this accordingly.
  • a color camera is used for this purpose.
  • the use of two or three black-and-white cameras with corresponding color filters may be considered, depending on the number of colors used.
  • averaging can be carried out for the corresponding pixels.
  • the use of multiple pixels for one mirror can increase the resolution of the tilt measurements and thus improve the association of the image area imaged in the camera with the default pattern. Accordingly, with the illustrated embodiment, monitoring of a plurality of tiltable mirrors in a mirror field, for example in a micromirror array (MMA), can be carried out in a simple manner, which can be used, for example, for illumination adjustment in projection illumination systems for microlithography.
  • MMA micromirror array
  • FIG. 6 shows a further embodiment of a pattern which can be used with the arrangement of FIG.
  • This pattern is a periodic representation of light sources with different wavelengths, for example a white light. lenin in the red wavelength range and a wavelength in the green wavelength range, wherein the periodicity of the radiation power of the light sources or the intensity of the light radiation in the specific wavelength.
  • the intensity of the light radiation over the region predetermined by the xy surface of the pattern can have a sinusoidal profile in each case in the x and y directions.
  • the sinusoidal curve for the red wavelength range can be arranged in the direction of the x-axis, while the sinusoidal profile of the intensity in the green wavelength range extends along the y-axis. This results in a checkerboard-like pattern with intensity maxima with high light intensity of the green and red light radiation and intensity minima with low red and green light intensity.
  • the detection device can accordingly be formed by a color camera, so that the corresponding sensor can determine the color components of the reflected pattern or two black-and-white cameras with corresponding color filters, that is to say a red filter and a green filter in the example chosen, can be used to add the corresponding color components measure up.
  • the tilt angle around the first tilt axis can be determined in each case in the first color channel by a phase determination.
  • the second tilt angle can be determined.
  • the background is that the strip or sine pattern in the first color channel of the camera image shifts due to a tilting about a first tilting axis (phase change).
  • the stripe or sinusoidal pattern shifts in the second color channel.
  • at least nine pixels, ie detection points per mirror are accordingly required.
  • more pixels or detection points per mirror for example 16 or 25.
  • the phase measurement can be ambiguous, ie it is not directly detect the absolute mirror position or the Spiegelkipps perform, but only a detection of the relative position or the relative tilt.
  • tracking the mirror movement can nevertheless realize a measuring system, which provides the Spiegelkipp or the mirror position.
  • Prerequisite for the applicability of a tracking is often that the Frame rate of the camera (equal sampling rate of the measurement) is high compared to the time constant of the mirror dynamics. That is, the mirror moves slowly compared to the temporal sampling rate.
  • FIGS. 7 to 9 show an example of a corresponding image produced by a mirror of the pattern of FIG. 6 in the camera 1.
  • FIG. 7 shows partial images for three juxtaposed mirrors 50, 51, 52, in which, according to FIGS. 8 and 9, the images of the red channel and the green channel are provided in the associated pixel region of the camera.
  • the rectangle shown in FIG. 7 for the mirrors 50, 51, 52 respectively corresponds to the left partial images of FIGS. 8 and 9, wherein in FIGS. 8 and 9 the green and red partial image and the correspondingly depicted sinusoidal pattern respectively are shown.
  • the sine pattern with wavelengths in the green light range there is a section of slightly more than one period, while for the red channel, ie the light in the wavelength range of the red light, slightly more than two periods of the sine pattern are detected ( see right part of Figs. 8 and 9). If there is a tilting of the corresponding mirror about the x- or y-axis, then the detected sine curve of the green or red light changes and the change in the tilt angle can be detected by changing the phase of the sinusoidal curve. However, as soon as the tilt angle leads to a shift of the sine signal by more than one period, a tracking of the movement of the mirror must be performed (see also below incremental measurement) in order to continue to maintain an absolute localization in the periodic pattern ,
  • This pattern is a random signal, or a noise pattern, in which it is assumed that the probability that repeating pattern areas are found in the surface area of the x-y area of the pattern is extremely small.
  • the pattern of FIG. 10 may also be present as an expression or as a representation on a screen, for example a TFT monitor.
  • a corresponding noise signal can be used for display.
  • a corresponding pattern by a lacquered or structured by other surface treatment surface within the projection exposure system for example, be given a corresponding housing wall.
  • the assignment of the determined mirror image which in turn is shown in FIG. 11, for example, for three mirrors 50, 51, 52 arranged next to one another, takes place, for example, via correlative methods which allow the image and pattern to be associated.
  • FIGS. 12 and 13 each show four partial images, which have been taken in succession from the pattern. It can be seen here that there is a time-varying pattern in which, for example, a sine wave passes through the pattern surface, both in the x direction and in the y direction for measuring the x tilt angle and the y tilt angle. Contrary to the pattern from FIG. 6, this is therefore not a standing sine wave, but a sine wave passing through in time, so that a periodic change in the radiation of the light sources occurs at all locations of the pattern over time.
  • the phase of the time signal can be determined, which is a measure of the tilt of a mirror in the x- or y-axis.
  • Such a phase shifting method as used, for example, for the defect detection of painted parts in the automotive industry, can thus also be used for determining the orientation of a mirror and in particular a plurality of mirrors in a mirror array.
  • the rate of the pattern change in the MHz range can be selected, in particular light emitting diode arrays can be used, which can be switched very quickly.
  • the use of light-emitting diodes with two different wavelength ranges of the light can be realized again, wherein by rapidly switching the corresponding lighting diodes of a first wavelength range, for example in red color, the continuous sine wave in the x-direction and switching the LEDs with the second wavelength range, the generation of the continuous sine wave in the y-direction can be generated.
  • a filter may be provided to realize, for example, an optical low-pass filter, for example in the form of a frosted glass.
  • the corresponding mirrored pattern is recorded with at least three images per mirror position or Spiegelkipp from a color camera or two black and white cameras with color filter also high frame rate, so that the tilt angle of the mirror can be determined by a corresponding evaluation.
  • a photodiode array for detection is also conceivable. With such an approach, it is in principle also possible that only one pixel or a detection point, for example a photodiode per mirror, is provided.
  • FIG. 14 again shows in a schematic representation details of the reflection conditions between the pattern 302, which in the exemplary embodiment shown is provided by a TFT display, the mirror 304 to be measured, whose position is to be determined, and the camera or detection device 301 As clearly shown by the dashed representation of the tilting mirror 304, a different tilting position of the mirror 304, another area of the pattern 302 is detected by the detection device 301 in the form of the camera. This provides the basis for the phase-measuring deflectometry used in one embodiment of the present invention.
  • FIG. 15 shows three snapshots of a temporally and locally changeable pattern, as it is displayed on the TFT display 302 at different times.
  • the tilt in the x and y directions can follow simultaneously, with either different wavelengths being used for the x and y directions, for example for x Direction green and red for the y direction, or a corresponding superimposed gray gradient through sine or cosine curves in the x and y directions.
  • the parameters n and m can be selected appropriately.
  • the parameter n which indicates the number of images used for the evaluation and thus the
  • Phase measurement represented in a first direction must be integer
  • the parameters n and m can be selected appropriately.
  • the parameter n that is to say the number of images to be used for the evaluation (measured value captures) may be in the range between three and twelve images, in particular four to twelve images, preferably six to twelve images.
  • the parameter m is then chosen as a fraction of the parameter n, the denominator again being of the order of magnitude of three to eight, in particular in the range of three to five.
  • other values are conceivable.
  • the accuracy of the phase measuring deflectometry can be increased when a multi-stage method is used.
  • the pattern for the first stage of the method may include a cosine period to roughly determine the positioning and orientation of the mirror.
  • the second stage several periods of the cosine signal (pattern) may be superimposed to perform the fine positioning. Due to the superimposition of a plurality of cosine signals, in the case of an ambiguity, that tilt angle or that positioning which comes closest to the coarse positioning from the first stage can be selected.
  • Such a superposed pattern method is also called phase unfolding.
  • phase-measuring deflectometry with phase unfolding with superimposed images for determining the position of mirrors and, in particular, for determining the tilt angles about an x and ay axis.
  • the phase unfolding process can be implemented in a single step, in addition to a multi-step process with separate images in the different stages for determining fine and coarse positioning, when all of the cosine signals are additively superimposed to produce the pattern.
  • the intensity is thus:
  • the parameters ⁇ , m, n, o and p can be selected for the evaluation or setting of the pattern.
  • the number of images (acquisitions) m can be a minimum of nine in order to solve the system of equations for the nine unknowns.
  • suitably suitable parameters can be used.
  • ⁇ which indicates the number of periods for the fine measurement, a value can be selected equal to 31, whereby it must be ensured that the coarse measurement and fine measurement are adapted to each other, so that incorrect measurements are not assigned to each other.
  • a temporally invariable pattern in which case several detection devices (cameras) are used for the use of phase-measuring deflectometry.
  • the pattern 402 points, for example, in x and y Direction a sinusoidal light-dark course (gray shading), which is periodically continued and shown in Figure 17.
  • FIG. 17 also shows, with the rectangles drawn in, the areas S1 to S5 which the cameras 401a, 401b, 401c, 401d and 401e (detectors) can detect from the pattern 402.
  • a different spatial phase of the temporally invariable pattern 402 is detected by changing the position of the cameras 401a to 40e, so that in turn the tilting of the mirror 404 can be determined.
  • the detection ranges S1 to S5 drawn in FIG. 17 show that, given a resolution of one pixel for a mirror, a multiplicity of mirrors in a mirror field can be measured simultaneously.
  • this procedure has the advantage that the various detection devices 401a to 40e can take a picture exactly at the same instant when they are connected to one another, for example via a trigger line.
  • This has the advantage that the mirror does not necessarily have to be constant during recording.
  • FIG. 16 A further modification of a corresponding arrangement or the corresponding method is shown in FIG.
  • a detection device (camera) 501 is provided in this arrangement, which provides different detection regions, wherein different mirrors 505 to 509 place the different regions of the temporally immutable pattern 502 into the different detection regions map the detection device 501.
  • the division of the detection range of the camera 501 can be done in any manner z. In 4, 6, 8, 9, 12 or 16 areas.
  • the excess detection range can be used for a determination of the mirror tilt over an absolute gray value or the like, so that mixing or combination methods can be realized, for example, the phase-measuring deflectometry and other methods for determining the tilt of a mirror can be used simultaneously.
  • other methods for coarse determination of mirror tilting can also be used for two-stage methods be used to make the fine determination with the phase-measuring deflectometry or vice versa or make other combinations.
  • the different detection ranges of the camera 501 it is also possible to use the different detection ranges of the camera 501 to apply the two-dimensional, phase-measuring deflectometry twice, for. Once with 5 detection areas (images) for the coarse position determination and on the other with 7 detection areas (images) for the fine positioning. In this case, several cosine periods can be provided in the pattern. Due to the higher resolution of the first two-dimensional, phase-measuring deflectometry, 20 cosine periods in the pattern for the second phase-measuring deflectometry are readily conceivable.
  • FIG. 19 shows an embodiment of a pattern generation device in which a pattern is formed on a projection screen 602.
  • a plurality of light sources 630, 631, 633 are provided, which irradiate a corresponding number of masks 620, 621, 623 in the direction of the projection screen 602, so that the patterns of the masks 620, 621, 623 on the projection screen.
  • a control unit 640 it is possible to switch the light sources 630, 631, 633 in a targeted manner one after the other and / or to change their intensity continuously so that the mask pattern on the projection screen 602 and / or its superimposition result in a corresponding pattern as a result of the successive imaging the projection screen 602 leads.
  • the light sources shown schematically projection devices such as or slide or beamer or the like can be used.
  • the advantage of such a pattern-generating device lies in the fact that the projection screen can be arranged relatively easily in a space under vacuum, while the light sources with the masks and the control unit can be provided outside the vacuum space.
  • the optics 610, 611, 613 or parts thereof can serve here as parts of the vacuum partition wall, so that such a pattern generation device can be used in particular in projection exposure systems with vacuum areas.
  • the projection devices with the numbers 0 to 3 then generate the following image:
  • x, y are the location coordinates, and X is the period of the pattern.
  • the total intensity I (x, y) on the projection screen results from an addition of the partial intensities Ii I 2, 1 3, 1 4 . If this is not the case with a specific structure (eg non-linear characteristic of the projection screen), this can be achieved by a corresponding transformation of the activation intensities i 1; Correct i 2> i 3 and i 4 .
  • the goal is the generation of a sine pattern with period X with adjustable phase ⁇ .
  • the light sources are controlled such that i 1; i 2 i 3 and i 4 represent cosine signals with additive constant displaced by 90 ° phases in each case:
  • a cosine signal having an adjustable phase ⁇ is produced on the projection screen as desired.
  • the phase can be set continuously (i.e., not quantized) by a corresponding control of the intensities of the light sources.
  • the phase ⁇ of the pattern can also be made comparatively quickly, so that fast controllable light sources, such. As LEDs, can be used. This allows a high temporal sampling rate in the measurement of Spiegelkippwinkeln achieve.
  • the continuous adjustment of the brightness of the light sources I 1 can be done via pulse width modulation (PWM).
  • PWM pulse width modulation
  • the pulse width modulation control has the advantage that no digital-to-analog converter are required and the light sources need only be switchable.
  • phase-shifting patterns For generating phase-shifting patterns (time-varying patterns), various methods can continue to be used.
  • the superposition of the individual patterns can take place here in the form of overlaid slide projections or the like.
  • the patterns are firmly imaged with different colors on a corresponding background and with special light, such as light from complementary colors, polarized light, etc., are illuminated, so that with the respective color or the light of certain polarization only the that pattern provides an intensity contribution which is associated with the corresponding light color or light polarization.
  • the corresponding method for generating the phase-shifted intensity curve can also be used for two-dimensional pattern, then at least six patterns should be provided, since the phase offset in the corresponding spatial directions, so x and y direction must be different in size.
  • the intensity profile can be set as follows:
  • Another way to create a corresponding pattern is to appropriately switch on and off light sources, such as simple lamps or LEDs (Light Emitting Diodes).
  • LEDs Light Emitting Diodes
  • FIG. 22 In the partial image a) of FIG. 22, corresponding illuminants, for example LEDs, are arranged at the locations where the numerals are shown. In sub-picture a), these are 17 LEDs, which are switched one after the other according to the numbering, resulting in five sample pictures.
  • the area inside the dashed inner square represents the effectively used pattern area, while the outer illuminants located in the intermediate area between the inner square and the outer square serve to provide the correct intensity distribution in the inner square caused by the corresponding intensity dispersion external light source is realized.
  • each lamp provided an intensity distribution of a cosine curve with the period length of the inner square, then an ideal phase-shifted cosine pattern would be given in two dimensions.
  • the lamps have a luminous characteristic similar to a Gaussian bell curve.
  • n and m for a two-dimensional, phase-measuring deflectometry with two superimposed periodic patterns, eg a cosine pattern in the x-direction and a cosine pattern in the y-direction (see above). , be made. Accordingly, for example, the value for the parameter n (number of images) could be set to eight, and the value for the parameter m could be set to 8/3.
  • FIG. 22 A corresponding arrangement of light sources is shown in FIG. 22 in the partial image b).
  • the numbers indicate again the position of the lamps and the corresponding turning on the lamps to produce the various patterns, so the digit 0, the position of the bulb 0, which is turned on for the pattern 0, the numeral 1, the position for the bulbs, the Pattern 1 are turned on, etc.
  • the light sources in the form of lamps, LEDs or so-called Gaussian spots can also be multiplied, for example by mirror assemblies, optical fibers or specially ground lens arrays in order to reduce the number of lamps or LEDs or the like.
  • n lamps that is to say as many lamps or Gaussian spots as the number of required pictures (detections) (see inner square area in FIG. 22).
  • n lamps that is to say as many lamps or Gaussian spots as the number of required pictures (detections) (see inner square area in FIG. 22).
  • n-3 bulbs or spots For the measurement with one period we recommend 4 * n-3 bulbs or spots.
  • Another possibility for producing a pattern and in particular a temporally and / or locally variable, that is moving pattern is to illuminate a corresponding mask or a perforated plate with different light sources, so that a corresponding pattern is produced on a diffusing screen.
  • This is shown, for example, in FIG. 23 in which three light sources, which can be switched individually, illuminate a perforated plate from three different positions, so that correspondingly different intensity maxima are produced on the diffusing screen, resulting in a shifting cosine profile. While only the generation is shown in one dimension in FIG. 23, it goes without saying that corresponding light sources perpendicular to the image plane can also be provided so that a two-dimensional pattern can be generated.
  • corresponding color filters can be provided in the various holes of the perforated plate, so that with the help of color cameras, a corresponding evaluation can be made.
  • the various methods presented can be combined with one another in order, for example, to enable different accuracies of the positioning determination and then to combine these together.
  • the coarse determination of the positioning could be carried out via a color code
  • the fine determination of the positioning takes place via two-dimensional lamp arrangements, so-called Gaussian spots.
  • optical incremental sensors for determining the mirror positioning.
  • the optical incremental sensors whether they pursue an interferential measuring principle or an imaging principle, have in common that the movement of a scale to a scanning element two signals offset by 90 degrees, namely a cosine and a sine wave, so on the basis of the Measurement determined signal variation, the position change and the position direction is made possible by comparing the signals offset by 90 degrees to each other.
  • a marking of a signal period a so-called index signal, is additionally provided. In other words, by counting the passing periods of the signals and comparing the waveforms of the signals offset by 90 degrees, the positional change can be determined and the absolute position is defined by the index signal.
  • This principle can generally also be used in determining the position of a mirror, for example by generating a pattern in which the red color component of the pattern has a sine curve, the green color component of the pattern has a cosine curve and a blue index signal is provided is.
  • the corresponding pattern which has been mirrored on the mirrors, can then be detected in order to determine the position by means of a corresponding evaluation of the red, green and blue components.
  • the incremental position determination according to the principle of optical incremental sensors can be used not only for the determination of the tilt about an axis of rotation, but also for the determination of the tilt angle about two independent axes of rotation. In this case, two patterns and two cameras should be provided accordingly.
  • each case only one mirror is moved out of the group of mirrors which are assigned to a camera pixel. Since the other mirrors show no change in position, the change detected in the camera pixel, for example, of the red and green components is attributable only to the one mirror, so that its positional change can be determined. For a corresponding Heydemann correction, however, should be tilted by at least one signal period.
  • the second possibility to measure several mirrors with one camera pixel is that all but one mirror are placed in such a way that they do not contribute to the camera pixel, thus for example reflecting a black background or border area in the camera pixels.
  • the light intensities detected by the camera or light intensities generally detected by a detection device can only be attributed to the remaining mirror, and this can be exactly determined in its position.
  • the measuring channels of the individual mirrors are largely decoupled, ie in most variants of the illustrated measuring methods / arrangements there is no crosstalk between the measuring channels for individual mirrors. The measured value of a mirror is then completely independent of the tilt angles or measured values of other mirrors.
  • An apparatus for monitoring the orientation of at least one mirror (4, 40) with detection means (1, 10) for detecting the light reflected from the mirror wherein a pattern source (2, 20) is provided having a pattern (3, 30) ) with spatially and temporally or temporally variable light sources (31), which is mirrored by the at least one mirror onto the detection device or that a pattern source (2, 20) is provided, which spatially and / or spatially intersperses a pattern (3, 30).
  • the detection device is designed such that the mirror or mirrors are imaged in a defined manner on the detection device and exactly one detection region of the detection device is associated with each mirror , or that a pattern source (2, 20) is provided, which has a pattern (3, 30) with spatially and / or temporally variable light intensity 31), which is mirrored by the at least one mirror onto the detection device, wherein the detection device is designed such that it detects changes in the detected pattern over time.
  • the device comprises an evaluation unit (7) which determines an absolute or relative position of the mirror or mirrors from the pattern to be mirrored and the detected, reflected light.
  • the detection means (1,10) comprises at least one element of the group, the Black and white cameras, black and white cameras with color filters, color cameras, charge coupled device (CCD) sensors, CMOS (complementary metal oxide semiconductor) sensors and photodiodes.
  • the detection device (1,10) comprises at least one optics, which is prepared so that can be focused on the pattern to be mirrored and / or on the mirror or mirrors and / or an area between them ,
  • the detection means (1,10) comprises a plurality of independent pixels for locally separated light detection, wherein each mirror is associated with at least one pixel.
  • each mirror (4, 40) is associated with at least 9 pixels.
  • each mirror (4, 40) is associated with at least 16 pixels.
  • each mirror is associated with at least 25 pixels.
  • Detection device (1,10) and pattern source (2,20) are so arranged relative to the one or more mirrors (4,40) that they do not interfere with one or more working beam paths of the mirror or mirrors. 11. Device according to one of the preceding features, wherein at least two detection devices are arranged.
  • a plurality of detection means are arranged side by side so that with respect to a mirror different reflection angle with respect to a fixed-time, locally periodic and / or sinusoidal or cosinus-shaped pattern are given, so that different areas of the Pattern in the various recording devices.
  • the detection device is designed so that over a period of time, continuously or at intervals, the pattern reflected by a mirror can be detected.
  • the pattern source (2,20) comprises at least one element of the group comprising a monitor, a TFT screen, a light field with and without filter, a light-emitting diode array, a structured surface, a painted surface , any textured or textured surface and a pattern image with and without illumination.
  • the pattern source (20) is prepared such that a pattern can be generated or present in at least one direction and / or in independent spatial directions (x, y direction) at least one periodic and / or sine or cosine pattern and / or multiple overlaid periodic and / or sine or cosine patterns
  • the pattern source (2, 20) comprises light sources of different wavelengths of light, the light of particular wavelengths being associated with particular positions in the pattern and / or varying in intensity over the pattern.
  • the pattern represents an area in which the intensity of the light of a first wavelength is continuously or stepwise changed in one direction and in another direction, the intensity of the light of a second wavelength is also changed.
  • the pattern source (20) can generate temporally variable patterns (30).
  • the pattern source (20) is prepared such that the phase of a periodic pattern and / or a sine or cosine pattern can be varied over time.
  • the pattern source (20) is prepared such that the pattern in at least one direction and / or in independent spatial directions (x, y direction) temporally successively or simultaneously and / or with light of different Wavelength can have time-variable periodic and / or sine or cosine patterns.
  • the pattern source (20) is prepared such that the temporally variable pattern is generated by temporally successive or temporally variable superimposition of different, temporally immutable pattern.
  • the pattern represents an area in which a randomly generated or any noise pattern is present.
  • pattern of the pattern source comprises a periodic grid or discrete areas with one or more light sources.
  • the pattern source comprises at least one light source, preferably a plurality of light sources whose radiation intensity is continuously or stepwise and / or periodically, in particular modulated by a pulse width modulated control.
  • the pattern source comprises a plurality of light sources, which are switchable in groups.
  • the pattern source comprises at least one mask which has a pattern and which is irradiated by at least one light source in the transmission mode or in the reflection mode.
  • the pattern source comprises a plurality of light sources which comprise a grid or a mask of illuminate different positions simultaneously, in groups and / or in succession or wherein each light source is associated with a mask for generating a pattern, wherein the patterns of multiple masks are superimposed and / or temporally successively generated.
  • the pattern source comprises at least one mask from the group comprising binary masks, grayscale masks, and color masks.
  • the pattern source comprises at least one luminescent screen on which the pattern can be generated.
  • the pattern source comprises at least one optic with which at least one pattern can be imaged.
  • the detection device (1, 10) is arranged and / or comprises optics, so that the detection device is focused on the mirror (s) and / or on the provided pattern or on an area therebetween, and or the mirror (s), and / or the pattern provided, or an area therebetween, are imaged onto the detector.
  • a parameter pair (n, m) can be selected, which with a first parameter (n) represents the number of acquisitions and corresponding to the different phases in a spatial direction and with a second parameter (m) representing the different phases in a different spatial direction, the second parameter (m) being a fraction of the first parameter (n) with the first parameter (n) in the numerator and an integer denominator.
  • Method according to one of features 35 to 51 wherein the pattern is arranged in at least one direction and / or in independent spatial directions (x, y direction) successively or simultaneously and / or with light of different wavelengths corresponding to periodic and / or sinusoidal or cosine pattern is varied over time.
  • a first multiple-mirror arrangement (110) is arranged in a lighting system (152) in a field plane, which directs the working light onto a field-defining element (FDE) or a second multiple-mirror arrangement (120) in a pupil plane wherein for monitoring the first multi-mirror arrangement, a device according to one of the features 1 to 19 is arranged such that detection means and pattern source corresponding to an inverted beam path of the working light from virtual light source to the pupil plane of the field-defining element or the second multi-mirror array are arranged.
  • a projection exposure apparatus according to claim 63 or 64, wherein the pattern of the pattern source in the arrangement of the light sources corresponds to the structure of the second multi-mirror array.
  • Projection exposure system according to one of the features 63 to 65, wherein at least part of an optical system of the pattern source and / or an optical system of the detection device serves as a component of a gas-tight separation, in particular a vacuum partition wall.

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Abstract

L'invention concerne un dispositif et un procédé correspondant de contrôle de l'orientation d'au moins un miroir (4), notamment d'une pluralité de miroirs dans un champ de miroirs tel qu'utilisé par exemple dans un système d'éclairage par projection pour la microlithographie. Selon l'invention, un dispositif de détection (1) est prévu pour détecter la lumière réfléchie par le miroir, et une source de motif (2) fournit un motif (3) au moyen de sources de lumière variables dans l'espace et/ou dans le temps, le motif étant réfléchi par le ou les miroirs sur le dispositif de détection. L'orientation du miroir peut être déterminée à partir de l'image réfléchie détectée par le dispositif de détection.
PCT/EP2010/051876 2009-02-18 2010-02-15 Contrôle de miroirs pivotants Ceased WO2010094658A1 (fr)

Applications Claiming Priority (2)

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DE102009009372.9 2009-02-18
DE200910009372 DE102009009372A1 (de) 2009-02-18 2009-02-18 Monitoring von kippbaren Spiegeln

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WO2010094658A1 true WO2010094658A1 (fr) 2010-08-26

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Cited By (10)

* Cited by examiner, † Cited by third party
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DE102013201506A1 (de) 2012-02-17 2013-08-22 Carl Zeiss Smt Gmbh Optisches Bauelement
WO2014053659A1 (fr) 2012-10-05 2014-04-10 Carl Zeiss Smt Gmbh Procédé et composant de régulation de l'inclinaison d'un élément de miroir
DE102014210383A1 (de) 2014-06-03 2014-08-07 Carl Zeiss Smt Gmbh Mit filter optimiertes monitoring von kippbaren spiegeln
DE102013217260A1 (de) 2013-08-29 2014-09-25 Carl Zeiss Smt Gmbh Messung des Kippwinkels von kippbaren Spiegeln mit einer Messlichtanordnung
DE102013217655A1 (de) 2013-09-04 2014-10-02 Carl Zeiss Smt Gmbh Spiegelmonitoring unter Verwendung einer Graustufenblende
DE102013222935A1 (de) 2013-11-11 2015-05-13 Carl Zeiss Smt Gmbh Vorrichtung zum Ermitteln eines Kippwinkels wenigstens eines Spiegels einer Lithographieanlage sowie Verfahren
DE102016226084A1 (de) 2016-12-22 2017-03-02 Carl Zeiss Smt Gmbh Vorrichtung zur überwachung mindestens einer kippstellung mindestens eines spiegels
KR20180010226A (ko) * 2015-05-20 2018-01-30 칼 짜이스 에스엠테 게엠베하 리소그래피 시스템의 적어도 하나의 미러의 위치를 결정하기 위한 위치 센서 디바이스 및 방법
KR20200017497A (ko) * 2017-06-20 2020-02-18 칼 짜이스 에스엠테 게엠베하 공간 내의 가동 대상체의 위치를 결정하기 위한 시스템, 방법 및 마커

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DE102012218221A1 (de) * 2012-10-05 2014-04-10 Carl Zeiss Smt Gmbh Monitorsystem zum Bestimmen von Orientierungen von Spiegelelementen und EUV-Lithographiesystem
DE102013204015A1 (de) 2013-03-08 2014-09-11 Carl Zeiss Smt Gmbh Spektralzerlegung zur Mikrospiegelkippwinkelbestimmung
DE102014207865A1 (de) 2014-04-25 2014-07-24 Carl Zeiss Smt Gmbh Kippspiegelüberwachung
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Cited By (21)

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WO2013120926A1 (fr) 2012-02-17 2013-08-22 Carl Zeiss Smt Gmbh Composant optique
DE102013201509A1 (de) 2012-02-17 2013-08-22 Carl Zeiss Smt Gmbh Optisches Bauelement
DE102013201506A1 (de) 2012-02-17 2013-08-22 Carl Zeiss Smt Gmbh Optisches Bauelement
WO2013120927A2 (fr) 2012-02-17 2013-08-22 Carl Zeiss Smt Gmbh Composant optique
US10078271B2 (en) 2012-02-17 2018-09-18 Carl Zeiss Smt Gmbh Optical component
US9804501B2 (en) 2012-02-17 2017-10-31 Carl Zeiss Smt Gmbh Optical component
WO2014053659A1 (fr) 2012-10-05 2014-04-10 Carl Zeiss Smt Gmbh Procédé et composant de régulation de l'inclinaison d'un élément de miroir
DE102012218219A1 (de) 2012-10-05 2014-04-10 Carl Zeiss Smt Gmbh Verfahren zur Regelung der Verkippung eines Spiegelelements
DE102013217260A1 (de) 2013-08-29 2014-09-25 Carl Zeiss Smt Gmbh Messung des Kippwinkels von kippbaren Spiegeln mit einer Messlichtanordnung
DE102013217655A1 (de) 2013-09-04 2014-10-02 Carl Zeiss Smt Gmbh Spiegelmonitoring unter Verwendung einer Graustufenblende
WO2015067442A1 (fr) 2013-11-11 2015-05-14 Carl Zeiss Smt Gmbh Dispositif permettant de déterminer un angle d'inclinaison d'au moins un miroir d'un système de lithographie
JP2016539386A (ja) * 2013-11-11 2016-12-15 カール・ツァイス・エスエムティー・ゲーエムベーハー リソグラフィーシステムの少なくとも１つのミラーの傾斜角を測定する装置及び方法
DE102013222935A1 (de) 2013-11-11 2015-05-13 Carl Zeiss Smt Gmbh Vorrichtung zum Ermitteln eines Kippwinkels wenigstens eines Spiegels einer Lithographieanlage sowie Verfahren
US10007195B2 (en) 2013-11-11 2018-06-26 Carl Zeiss Smt Gmbh Device for determining a tilt angle of at least one mirror of a lithography system, and method
DE102014210383A1 (de) 2014-06-03 2014-08-07 Carl Zeiss Smt Gmbh Mit filter optimiertes monitoring von kippbaren spiegeln
KR20180010226A (ko) * 2015-05-20 2018-01-30 칼 짜이스 에스엠테 게엠베하 리소그래피 시스템의 적어도 하나의 미러의 위치를 결정하기 위한 위치 센서 디바이스 및 방법
KR102600797B1 (ko) 2015-05-20 2023-11-10 칼 짜이스 에스엠테 게엠베하 리소그래피 시스템의 적어도 하나의 미러의 위치를 결정하기 위한 위치 센서 디바이스 및 방법
DE102016226084A1 (de) 2016-12-22 2017-03-02 Carl Zeiss Smt Gmbh Vorrichtung zur überwachung mindestens einer kippstellung mindestens eines spiegels
DE102017221023A1 (de) 2016-12-22 2018-06-28 Carl Zeiss Smt Gmbh Vorrichtung zur überwachung mindestens einer kippstellung mindestens eines spiegels
KR20200017497A (ko) * 2017-06-20 2020-02-18 칼 짜이스 에스엠테 게엠베하 공간 내의 가동 대상체의 위치를 결정하기 위한 시스템, 방법 및 마커
KR102559963B1 (ko) 2017-06-20 2023-07-26 칼 짜이스 에스엠테 게엠베하 공간 내의 가동 대상체의 위치를 결정하기 위한 시스템, 방법 및 마커

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