Method and measuring device for determining a position of a test object

Abstract

Proposed is a method for determining a position of a test object (12), comprising the following steps: determining the position of the test object in at least one translational degree of freedom (19-1; 19-2) transverse to a first measurement beam, by means of a translational measurement in which a measurement edge (18-1; 18-2) of a measurement element (16-1; 16-1'; 16-2; 16-2') assigned to the test object is measured by way of a relative translational movement (38) with respect to the first measurement beam (22-1) through a cross-section (53) of the first measurement beam and, at a plurality of positions of the translational movement, an intensity of the first measurement beam is measured at a measurement location (23) situated downstream of the measurement element; and determining the position of the test object in at least one rotational degree of freedom (20-1; 20-2) with respect to an axis of rotation oriented transversely to the first measurement beam, by means of a tilt measurement in which at least one beam interruption element (70-1; 70-2; 71-1; 72-2) assigned to the test object is moved by way of a tilting movement (79), relative to a further measurement beam (22-2) irradiated transversely to the axis of rotation (78) of the rotational degree of freedom, such that an interruption state of the further measurement beam is changed, and an intensity of a radiation component of the further measurement beam which passes through the beam interruption element is measured at different positions (80-1, 80-0, 80+1) of the tilting movement, wherein the first measurement beam and the further measurement beam are generated by different light beams or by a uniform light beam in different orientations with respect to the test object.

Description

Method and measuring device for determining the position of a test object The present application claims priority from German patent application 102025 111 171.5 dated March 24, 2025. The entire disclosure of that patent application is incorporated by reference into the present description. Background of the invention The invention relates to a method and a measuring device for determining the position of a test object, in particular an optical element, and a reflectometer for determining the reflectance of a test object using such a measuring device. Various industrial applications require precise position measurement of an optical element, particularly when determining its reflectance using a reflectometer. Reflectometers are commonly defined as measuring devices used to determine the reflectance of a test object with respect to electromagnetic radiation. For this purpose, the test object is scanned with a measuring beam. The reflectance, also called reflectivity, is the ratio between the intensity of the reflected electromagnetic radiation and the intensity of the incident electromagnetic radiation. For highly accurate reflectance measurements using a reflectometer, the test object's position relative to the measuring beam must be determined as precisely as possible. German patent DE 102017201 794 B4 describes a testing device for measuring the absolute position of an object in a reflectometer relative to the beam position of a light beam. This allows the device to determine the absolute position of the object when the absolute beam position of the light beam is known. The position measurement is performed in one translational degree of freedom and one rotational degree of freedom by moving an edge region of the object into the light beam in various swivel orientations. The translational degree of freedom measured corresponds to the direction of movement of the edge region (e.g., the x-coordinate direction). The light beam travels in the z-coordinate direction, and thus, in a cross-sectional view, along the x-z plane in the direction of the edge region. This is the case for each of the aforementioned swivel orientations relative to the z-axis.The measured rotational degree of freedom relates to a rotational axis aligned parallel to the z-axis and thus parallel to the direction of the edge region in the aforementioned sectional view. Furthermore, the aforementioned publication describes the possibility of measuring three objects on one measuring table, which also allows the translational degree of freedom in the y-direction to be measured. The edge area measurement described in DE 102017201 794 B4 does not, however, allow the determination of the rotational degrees of freedom with respect to the x-axis or the y-axis, i.e., a rotational degree of freedom with respect to a rotational axis that is oriented perpendicular to the measuring edge in the aforementioned sectional view. Therefore, the accuracy of the position measurement remains limited. Underlying task It is an object of the invention to provide a method and a measuring device of the type mentioned above, which solves the aforementioned problems and preferably enables position determination in at least one further rigid body degree of freedom with high accuracy. Inventive solution The aforementioned problem can be solved according to the invention, for example, by a method for determining the position of a test object. The method comprises the step of determining the position of the test object in at least one translational degree of freedom, in particular in two translational degrees of freedom, transverse to a first measuring beam by means of a translational measurement in which a measuring edge of a measuring element associated with the test object is moved by means of a relative translational movement with respect to the first measuring beam through a cross-section of the first measuring beam and an intensity of the first measuring beam is measured at several positions of the translational movement at a measuring location downstream of the measuring element. Furthermore, the method comprises the step of determining the position of the test object in at least one rotational degree of freedom, in particular in two further rotational degrees of freedom, with respect to an axis of rotation.which is oriented perpendicular to the first measuring beam, by means of a tilt measurement, in which at least one beam interruption element assigned to the test object is moved by means of a tilting movement relative to a further measuring beam emitted perpendicular to the rotational axis of the rotational degree of freedom such that an interruption state of the further measuring beam is changed, and an intensity of a radiation component of the further measuring beam which passes the beam interruption element is measured at different positions of the tilting movement, wherein the first measuring beam and the further measuring beam are generated by different light beams or by a uniform light beam in different orientations with respect to the test object. Under the specification that the rotational axis of the rotational degree of freedom is oriented perpendicular to the first measuring beam, an arrangement with an angular deviation of at least 30°, at least 60°, or approximately 90° is suitable. The position measurement is performed specifically with respect to the respective measuring beam. If the respective positions of the measuring beams are known, the measured position of the test object is absolute. The wavelength of the first and second measuring beams can, for example, be in the EUV or DUV wavelength range. As stated above, the measuring edge is moved through the cross-section of the first measuring beam. This can be achieved, for example, by moving the measuring edge into or out of the measuring beam. The measuring edge can also be moved from a state partially inserted into the cross-section to a state more fully inserted into the cross-section, and vice versa.In particular, the measuring edge can also be moved completely through the cross-section. Measuring the intensity of the first measuring beam at a measurement point downstream of the measuring element means measuring at a location that is downstream of the measuring element in the path of the first measuring beam. This means, for example, that the measurement can be performed by measuring the intensity of a portion of the radiation reflected from the first measuring beam when the measuring edge is partially engaged in the first measuring beam. For this purpose, a detector could be positioned at a suitable point in the path of the reflected radiation. Alternatively, the measurement can also be performed by measuring the intensity of the portion of the radiation that passes the measuring element along the measuring edge in the aforementioned state, i.e., that is not blocked by the measuring element. In this case, a detector could also be positioned at a suitable point in the path of the radiation passing the measuring element. The additional measuring beam, directed transversely to the axis of rotation of the rotational degree of freedom, is preferably tilted at least 20°, at least 50°, at least 80°, at least 85° or exactly 90° relative to the axis of rotation. The relative translational movement of the measuring edge to the first measuring beam includes the following variants: translational movement of the measuring edge with the first measuring beam in a fixed position, translational movement of the first measuring beam with the measuring edge in a fixed position, and coordinated translational movements of the measuring edge and the first measuring beam. The measuring element associated with the test object preferably refers to a measuring element with a known positional relationship to the test object; that is, the position of the measuring element relative to the test object is known. For example, the measuring element can be arranged on a support object rigidly connected to the test object, such as a measuring table, or even on the test object itself. Alternatively, the positional relationship can also be known based on a position measurement between the test object and the measuring element.Similarly, the beam interruption element is preferably also an element with a known positional relationship to the test object. According to one embodiment, during translational measurement, the measuring edge undergoes translational movement while maintaining a constant rotational position. In another embodiment, the test object also undergoes translational movement while maintaining a constant rotational position. The rotational movement used in rotational measurement is advantageously a continuous rotational movement, i.e., a rotational movement that is not interrupted by a translational movement with subsequent intensity measurements. A rotational movement that is only briefly interrupted once or several times by a standstill, or that changes its direction of rotation, is still considered a continuous rotational movement in this context. According to a further embodiment, the measuring edge forms an upper edge of a measuring aperture integrated into the measuring element and the first measuring beam runs in a sectional view in the direction of the measuring aperture, in particular essentially parallel to the measuring aperture. The combination of the tilt measurement described above with the translation measurement according to the invention makes it possible to measure the position of the test object with high accuracy not only in the at least one translational degree of freedom, but also in at least one rotational degree of freedom with respect to a rotational axis which is oriented transversely to the measuring edge in the sectional view. Thus, the determined position is available in more degrees of freedom and therefore exhibits higher accuracy and usefulness overall. According to one embodiment, by combining the tilt measurement with the translation measurement, the position of the test object can even be determined in all six rigid body degrees of freedom, i.e., in all three translational degrees of freedom and all three rotational degrees of freedom. According to one embodiment, the test object is an optical element, in particular an optical element for microlithography, such as an optical element for a microlithographic projection exposure system, which is designed, for example, for operation in the DUV or EUV wavelength range. According to a further embodiment, the test object is assigned a further measuring element with an additional measuring edge. The translational measurement further comprises a measurement at the additional measuring edge, and the position of the test object in a further rotational degree of freedom is determined by means of the translational measurement. Preferably, the axis of rotation of the additional rotational degree of freedom determined by means of the translational measurement runs in the direction of the first measuring beam, advantageously essentially parallel to the first measuring beam. According to another embodiment, the measuring edge of the measuring element is designed in an arc shape. According to a further embodiment, during translational measurement, the measuring edge is moved with several relative translational movements to the first measuring beam such that a respective path of the first measuring beam, traversed in the plane of the measuring element during the various translational movements, intersects the measuring edge at a specific location. According to one embodiment variant, the various translational movements are parallel and / or perpendicular to each other. In particular, the translational movements can comprise a set of translational movements aligned parallel to each other, as well as a set of further translational movements that are also aligned parallel to each other and perpendicular to the translational movements of the first set. According to a further embodiment, the coordinates of several intersection points of the measuring edge with a path traveled by the measuring beam in the plane of the measuring element are determined from the intensity values ​​measured during the translation measurement, a mathematical description of the course of the measuring edge is fitted to the determined coordinates, wherein a fitting result includes a geometric center of gravity of the course of the measuring edge, and the position of the test object in two translational degrees of freedom is determined from a deviation of the geometric center of gravity from a target position. According to one design variant, the measuring edge has a circular profile and the geometric center of gravity encompassed by the fitting result is the center of the circle of the measuring edge profile. According to another variant, the mathematical description of the measuring edge's path includes a modified circle equation that takes into account deviations from the ideal circle equation due to the angle of incidence of the first measuring beam with respect to the plane of the test object. The angle of incidence is defined as the angle between the incident measuring beam and the perpendicular to the plane of the test object (the normal of incidence). According to a further embodiment, the first measuring beam and the subsequent measuring beam are generated by a single light beam in different orientations relative to the test object. According to another embodiment, the test object is attached to the test object using a mounting tool. This involves first attaching the mounting tool to the test object and then using the mounting tool to engage the test object with a holding element of the test object. The mounting tool can be attached, for example, by means of a plug connection between the mounting tool and a recess in the test object. That is, the first measuring beam is formed by the light beam of a first orientation, while the subsequent measuring beam is formed by the light beam of a different orientation. According to a further embodiment, an additional translational degree of freedom is determined by means of the tilt measurement, wherein the additional translational degree of freedom determined by means of the tilt measurement advantageously extends in the direction of the first measuring beam, preferably substantially parallel to the first measuring beam. That is, the position of the test object is determined by means of the tilt measurement in the at least one rotational degree of freedom as well as in an additional translational degree of freedom. According to a further embodiment, during tilt measurement, a pair of beam interruption elements are arranged on opposite sides of the test object. During the tilting movement, one of the beam interruption elements is moved out of the measuring beam, and at a later time, the other beam interruption element is moved into the measuring beam. This allows the aforementioned additional translational degree of freedom to be determined by means of the tilt measurement. According to a further embodiment, the tilting movement includes a tilting base position in which the additional measuring beam passes the two beam interruption elements at the same distance. After the intensity measurements during the tilting movement, the distance in the tilting base position is changed, and further intensity measurements are carried out during a further tilting movement with the changed distance. This allows the additional translational degree of freedom to be determined with higher accuracy. According to a further embodiment, the intensity measurements in the tilt measurement include a measurement of the intensity of a radiation component of the further measuring beam passing through both radiation interruption elements, wherein the passing radiation component is generated at positions of the tilting movement where one of the two beam interruption elements partially blocks the further measuring beam. According to a further embodiment, during tilt measurement, another pair of beam interruption elements is arranged on opposite sides of the test object such that a connecting line between the beam interruption elements of the further pair is tilted relative to a connecting line between the beam interruption elements of the first pair, in particular by at least 50° or at least 70°, for example by about 90°. The tilt measurement determines the position of the test object in two further rotational degrees of freedom. In other words, the position of the test object is measured in one rotational degree of freedom by means of translation measurement and in two further rotational degrees of freedom by means of tilt measurement. According to a further embodiment, the method also includes a rotation measurement in which a third measuring beam is reflected from a reflective surface of the test object, the test object is moved by means of a rotational movement about an axis of rotation oriented transversely to the reflective surface, and for the various positions of the rotational movement, the impact position of the reflected measuring beam on a detector is measured. The rotation measurement can be used to verify the result of the position measurement with respect to the rotational degrees of freedom and / or to determine the position of the test object in a second and third rotational degree of freedom. The third measuring beam can be generated by the same light beam as the first measuring beam and / or the other measuring beam.The third measuring beam can have a different orientation and / or a different positioning than the first or subsequent measuring beams with respect to the test object. The axis of rotation can be tilted, in particular, by at least 1° and at most 89°, preferably by at least 1° and at most 30°, and, in the case of reflection at a grazing angle of incidence, preferably by at least 60° and at most 70° relative to the reflective surface of the test object. According to another embodiment, the position of the test object in at least one rotational degree of freedom is determined from the measured values ​​of the impact positions by fitting the measured values ​​to expected impact positions, wherein the at least one rotational degree of freedom is defined as a fitting variable. Furthermore, according to the invention, a measuring device for determining the position of a test object is provided, which comprises a measuring table for holding the test object as well as a measuring element with a measuring edge and at least one beam interruption element. Furthermore, the measuring device comprises a measurement beam generation module for generating a first measurement beam and a second measurement beam from different light beams or a single, uniform light beam in different orientations relative to the test object, and a positioning system for the relative positioning of the measuring element and the first measurement beam to each other, as well as the beam interruption element and the second measurement beam to each other. The positioning system is configured to move the measuring edge through a cross-section of the first measurement beam by means of a relative translational movement, and to move the beam interruption element relative to the second measurement beam by means of a tilting movement such that the interruption state of the second measurement beam is changed.Furthermore, the measuring device comprises a detection module for measuring the intensity of the first measuring beam at several positions along the translation at a measurement location downstream of the measuring element, as well as for measuring the intensity of a radiation component of the subsequent measuring beam, which passes through the beam interruption element, at various positions along the tilting movement. The measuring device also comprises an evaluation module configured to determine the position of the test object in at least one translational degree of freedom from the measured intensities of the first measuring beam, and to determine the position of the test object in at least one rotational degree of freedom arranged transversely to the direction of incidence of the subsequent measuring beam from the intensities measured at the various positions along the tilting movement. The measuring element can be arranged on the measuring table, i.e., connected to the measuring table independently of the test object. Alternatively, the measuring element can be arranged above the test object on the measuring table, i.e., it can be, for example, part of the test object and thus only be arranged on the measuring table during the measurement process. Preferably, a relative positioning between the beam interruption element and the measuring table is known; advantageously, the beam interruption element is arranged on the measuring table, i.e., connected to the measuring table independently of the test object. Furthermore, according to the invention, a reflectometer for determining a reflection property of a test object is provided, which includes a measuring device in one of the embodiments or variants described above for determining a position of the test object. The measurement of the reflection property, for example the reflectance, of the test object is advantageously carried out with a measuring beam whose position is known in relation to the respective position of the measuring beams used for position measurement of the measuring device, so that the position of the test object determined by means of the measuring device is known in any case in relation to the measuring beam used for measuring the reflectance. According to one embodiment, the reflection of the additional measuring beam occurs at the reflective surface in the region of the axis of rotation. In other words, the point of reflection deviates only slightly from the intersection of the axis of rotation with the reflective surface. "Slightly" here means, for example, at most 1% or at most 20% of the dimensions of the test object perpendicular to the additional measuring beam. According to another embodiment, the reflective surface at which the further measuring beam is reflected is a central area of ​​a mirror surface of the test object (the test object can in particular be designed as a mirror for microlithography). According to another embodiment, the position of the test object in two rotational degrees of freedom perpendicular to the axis of rotation is determined from the measured impact positions. For this purpose, for example, the measured values ​​of the impact positions are fitted to expected impact positions, whereby the rotational degrees of freedom are defined as variables of the fitting procedure. According to a further embodiment, after measuring the impact positions for the various positions of the rotational movement, the angle of incidence of the further measuring beam on the reflective surface is changed, and impact positions for various positions of a further rotational movement are measured with the changed angle of incidence. The position of the test object is then determined in a further translational degree of freedom by means of the rotational measurement. Alternatively, the further translational degree of freedom can be measured by means of a separate height scan of the test object. The features specified with regard to the aforementioned embodiments, exemplary embodiments, or variants, etc., of the method according to the invention can be transferred accordingly to the measuring device according to the invention, and vice versa.These and other features of the embodiments according to the invention are explained in the description of the figures and the claims. The individual features can be implemented either separately or in combination as embodiments of the invention. Furthermore, they can describe advantageous embodiments that are independently patentable and whose protection may be claimed only during or after the filing of the application. Brief description of the drawings The foregoing, as well as further advantageous features of the invention, are illustrated in the following detailed description of exemplary embodiments or embodiments or variants of the invention with reference to the accompanying schematic drawings. These show: Fig. 1 shows a measuring device for determining the position of a test object in all six rigid body degrees of freedom in an illustration of a translational measurement to determine two translational degrees of freedom and one rotational degree of freedom. Fig. 2 shows the function of evaluating measured values ​​in translational measurement. Fig. 3 shows the measuring device according to Fig. 1 in an illustration of a tilt measurement for determining two rotational degrees of freedom and one translational degree of freedom; Fig. 4 shows a top view of a measuring table of the measuring device according to Fig. 1 and Fig. 3. Fig. 5 shows a sectional view of a mounting tool for attaching a measuring element used for translation measurement to the test object. Fig. 6 shows the measuring device according to Fig. 1 in an illustration of a rotation measurement for determining one translational degree of freedom as well as two rotational degrees of freedom, Fig. 7 Beam paths of a measuring radiation for different rotational positions of the test object during the rotational measurement, as well as Fig. 8 shows an embodiment of a reflectometer with the measuring device according to Fig. 1. Detailed description of embodiments according to the invention In the exemplary embodiments or embodiments described below, functionally or structurally similar elements are, as far as possible, provided with the same or similar reference numerals. Therefore, to understand the features of the individual elements of a particular exemplary embodiment, reference should be made to the description of other exemplary embodiments or to the general description of the invention. To facilitate description, a Cartesian xyz coordinate system is shown in the drawing, from which the respective positional relationships of the components depicted in the figures can be derived. In Fig. 1, the y-direction runs perpendicular to the drawing plane and into it, the x-direction to the right, and the z-direction upwards. Fig. 1 shows a measuring device 10 for determining the position of a test object 12 in all six rigid body degrees of freedom, i.e., three translational degrees of freedom 19 and three rotational degrees of freedom 20. In the illustrated embodiment, the test object 12 is an optical element for microlithography in the form of a mirror with a reflective surface 13, for example, for a microlithographic projection exposure system. The projection exposure system can be designed, for example, for operation in the DUV or EUV wavelength range. While operation in the DUV wavelength range can take place, for example, at approximately 365 nm, approximately 248 nm, or approximately 193 nm, the EUV wavelength range extends to wavelengths below 100 nm and particularly concerns wavelengths of approximately 13.5 nm or approximately 6.8 nm. The measuring device 10 can be part of a reflectometer 200, shown by way of example in Fig. 8, for determining the reflectance of the test object 12. As explained in detail below with reference to Fig. 8, the precise position determination of the test object 12 by means of the measuring device enables a precise determination of the positioning of a measuring beam 222 of the reflectometer 200 with respect to the test object 12 during the reflectometric measurement. The measuring device 10 according to Fig. 1 comprises a measuring table 14 for holding the test object 12. Two measuring elements 16-1 and 16-2 are arranged on the measuring table 14 on different sides of the test object 12 for performing a translational measurement. Furthermore, the measuring table 14 has two pairs of beam interruption elements 70-1 and 70-2 as well as 72-1 and 72-2, the first pair of which, 70-1 and 70-2, is shown with dashed lines in Fig. 1. The measuring elements 16-1 and 16-2 are each designed in the shape of a cylinder, with the cylindrical surface being designated as the measuring aperture 17-1 and 17-2, respectively, and the circular upper edge of the cylindrical surface, which forms the transition to the cylinder's top surface (see reference numeral 21), being designated as the measuring edge 18-1 and 18-2, respectively. Figure 4, which illustrates a top view of the measuring table 14, shows the circular measuring edges 18-1 and 18-2 of the measuring elements 16-1 and 16-2. The measuring elements 16-1 and 16-2 can also be referred to as circular cutting apertures. The respective surface 21 of the measuring elements 16-1 and 16-2 (see Figure 1), which is formed by their respective cylindrical surfaces, is reflective to a measuring radiation. The measuring radiation, in the form of a first measuring beam 22-1, is directed successively onto each of the two measuring elements 16-1 and 16-2. Figure 1 shows the radiation directed onto the first measuring element 16-1. The measuring method will therefore also be described below, initially with reference to the first measuring element 16-1. The measuring beam 22-1 is generated by a measuring beam generation module 23. The measuring beam 222 of the reflectometer 200 according to Figure 8 can serve as the measuring beam 22-1; thus, the measuring beam generation module 23 can be a part of the reflectometer 200 that serves to generate the measuring beam 222. The measuring device 10 further comprises a positioning system 24 for the relative positioning of the measuring element 16-1 and the first measuring beam 22-1 to each other. In the illustrated embodiment, the positioning system 24 consists of a positioning module for positioning the measuring table 14 in all three translational degrees of freedom (translation 26 in the direction of the x-axis or translation 28 in the direction of the y-axis, as shown in Fig. 1, and translation 30 in the direction of the z-axis, as shown in Fig. 3) and at least two rotational axes (tilt 32 with respect to the y-axis, as shown in Fig. 1, or rotation 34 with respect to the z-axis, as shown in Fig. 3). The positioning system 24 can alternatively or additionally include a measuring beam positioning module for the measuring table 14 for the corresponding positioning of the measuring beam 22-1, if necessary without changing the positioning of the measuring table 14.As mentioned above, the measuring device 10 is configured to perform a so-called translational measurement according to Fig. 1 and a so-called tilt measurement according to Fig. 3. During the translational measurement, the measuring edge 18-1 is moved with several relative translational movements to the first measuring beam 22-1. In the embodiment according to Fig. 1, this is initially achieved by several translational movements 36 of the measuring table 14 in the negative x-direction (thus, the measuring beam 22-1 effectively performs a translational movement 38 in the positive x-direction). The translational movements 36 of the measuring table 14 in the x-direction occur at different y-positions. Thus, the measuring beam 22-1 traces several mutually parallel paths 42 in the plane of the measuring element 16-1 in the form of parallel lines, which the measuring edge 18-1 intersects at two different locations, as illustrated in the inset drawing 40.In the drawing inset 40, the two points of intersection with the circular measuring edge 18-1 are shown for one of the paths 42 extending in the x-direction, namely a front intersection point 44v and a rear intersection point 44h. Similarly, the measuring edge 18-1 is then moved in the negative y-direction at different x-positions by several translational movements 36 of the measuring table 14, whereby the corresponding paths 42 of the measuring beam 22-1 intersect the measuring edge 18-1 at two points 44v and 44h. The measuring beam 22-1 is directed onto the measuring element 16-1 such that, in the sectional view illustrated in Fig. 1, which runs along a section plane (xz-plane) oriented radially to the circular measuring edge 18-1, it is transverse to the measuring edge 18-1 and parallel to the measuring aperture 17-1. Thus, the directed measuring beam 22-1 is aligned parallel to the z-direction and therefore perpendicular to the x-axis for the path 42 running centrally in the x-direction according to the drawing inset 40. In the tangential direction to the circular measuring edge 18-1, the measuring beam 22-1 is directed at an angle of incidence. <t>(Reference symbol 41) is irradiated with respect to the plane of the test object 12 (xy-plane) or to the surface 21 of the measurement object 18-1. The angle of incidence <t>is defined as the angle of deviation from the perpendicular incidence of the radiation on the surface in question. Furthermore, the angle of incidence corresponds to... <t>the intermediate angle between the measuring edge 18-1 and the incident measuring beam 22-1 in a section plane parallel to the measuring edge 18-1 (see representation in the yz plane according to drawing inset 48). According to one embodiment, the angle of incidence <t>In a first measurement step, the angle is set to 1.5°, as illustrated in drawing inset 48 for the central path running in the x-direction. A radiation component 22-1 r of the measuring beam 22-1 is reflected at the surface 21 of the measuring element 16-1 at a corresponding angle. The measuring device 10 further comprises a detection module 46, which is arranged above the measuring table 14, specifically in the beam path of the reflected radiation component 22-1 r, i.e., at a measuring point downstream of the first measuring beam 22-1. According to an alternative embodiment, in which the measuring table 14 is configured to be transparent to the radiation of the measuring beam 22-1, the detection module 46 can also be arranged below the measuring table 14 in the beam path of the radiation component passing through the measuring table 14. According to an embodiment in which the measuring device 10 is integrated into the reflectometer 200 according to Fig. 8, the detection module 46 can correspond to the detection module 246 of the reflectometer 200. Alternatively, a separate detection module can be provided for this purpose. Preferably, the detection module 46 is attached to a positioning system (not shown in the drawing) configured to position the detection module 46 in a suitable position in the beam path of the reflected radiation component 22-1 r. The detection module 46 according to Fig. 1 records the intensity of the reflected radiation component 22-1 r during the individual translational movements (in the x and y directions) as a function of the x and y position of the measuring table 14, as exemplified in an intensity diagram 50 in Fig. 1. The surface of the measuring table 14 is preferably designed to be substantially non-reflective or only minimally reflective to the radiation of the measuring beam 22-1. As can be seen in the intensity diagram 50, the reflected intensity increases from an initial value to a maximum value when the measuring beam 22-1 enters the measuring element 16-1 in the region of the measuring edge 18-1 (left region of the measuring edge according to Fig. 1) and then decreases back to the initial value when it exits the measuring element, also in the region of the measuring edge 18-1 (right region of the measuring edge according to Fig. 1). An inset drawing 52 in Fig. 1 illustrates the state in which the measuring beam 22-1 is approximately halfway through its cross-section 53 into the measuring edge 18-1. In this state, approximately half of the cross-section of the measuring beam 22-1 is reflected at the surface of the measuring element 16-1, while the other half of the cross-section continues along the measuring edge 18-1 towards the measuring table 14. In this state, approximately 50% of the intensity of the maximum reflectable light of the incoming measuring beam 22-1 is reflected to the detection module 46. From the intensity diagram 50 recorded by the detection module 46 for the central path 42 running in the x-direction (see drawing inset 40), the x-positions for the front intersection point 44v and the rear intersection point 44h with path 42 are determined. From the previously known y-coordinate of path 42, the coordinates (x,y)i are thus obtained. KB1 and (x,y)2 KB1 Two intersection points 44 of a measuring beam path with the first measuring edge 18-1 (KB1) are measured. Similarly, the respective intersection points 44 of the further paths 42 extending in the x-direction and the paths extending in the y-direction are measured. In total, the coordinates (x,y)i are thus determined. KB1 The intersection points of 44 of all measured paths with the first measuring edge 18-1 are determined. The above measuring method is used for at least one further angle of incidence. <t>The procedure is carried out. According to one embodiment, a value such as 70° is chosen for this angle, at which the reflection of the measurement radiation occurs at grazing incidence (also known as the grazing incidence angle). Analogously, the second measurement edge 18-2 (KB2) is measured, whereby the coordinates (x,y)i are determined. KB2 the corresponding intersection points are determined. The entirety of all coordinates (x,y)i KB1 and (x,y)i KB2 are denoted in Fig. 1 by (x,y)i (reference numeral 54). The measuring device 10 further comprises an evaluation module 56. This evaluates the coordinates (x,y)i and thereby determines the position of the test object 12 in the translational degrees of freedom X and Y as well as the rotational degree of freedom 0. Z , which specifies the rotational position of the test object 12 with respect to the z-axis. As shown in Fig. 1, the evaluation module 56 comprises a first evaluation unit 58, which is configured to provide a mathematical description 60 of the course of the respective measuring edge 18-1 or 18-2 to the determined intersection point coordinates (x,y)i. KB1 (reference 54-1) or (x,y)i KB2 (reference symbol 54-2). The mathematical description 60 concerns a modified circle equation, which reads as follows: 2 R 2 = (x - (M x + AR • sin(e) ■ FZ)) 2 + (y - (M y - AR • COS( E) • FZ)} where FZ = sgn ; wrapToPi '■ atan2 . y - M y> x - M y ; - E )) Here, R denotes the circle radius, x and y the variables of the relation, Mx and M y The center coordinates of the circle, and AR a deviation of the circle radius R from a target value. The parameter s is a fit parameter, which is necessary because the coordinate system of the measuring elements 16-1 and 16-2, in which the intersection coordinates (x,y) are specified, is not always the same with respect to the rotation axis 0. Z is aligned. “wrapToPi (arg)” refers to the function known to experts from mathematical calculation programs, which corresponds to the function mod (arg+rr, 2TT) - TT. The modified circle equation takes into account deviations from the ideal circle equation. In the embodiment shown in Fig. 2, the modified circle 62 represented by the modified circle equation differs from the corresponding ideal circle 64 by bulges in both directions around the angle of incidence. <t>Longitudinal axis tilted relative to the x-axis. The angle of incidence <t>enters the equation of the circle via AR. Fig. 2 shows, as an example, the intersection point coordinates 54-1 determined for the measuring edge 18-1 during the translation measurement according to Fig. 1. The evaluation unit 58 uses a fitting procedure to adjust the modified circle equation for each of the measured angles of incidence. <t>by varying the parameters Mx, M y as well as AR at the intersection coordinates 54-1. For each angle of incidence <t>This results in an xy-coordinate of the circle's center (Mx, Mx). From this, the evaluation unit 58 determines a measurement result (M). x ,M y ) KB1 of the circle center of the first measuring edge 18-1 and thus the measured geometric centroid (66-1) as a fitting result. The parameter AR, which was also determined, can be used for verification purposes with respect to the previously known circle radius R of the measuring edge 18-1. Analogously, the measured circle center (Mx, M) y ) KB2 the second measuring edge 18-2 determined (reference numeral 66-2). From a deviation of the determined circle centers (Mx, M y ) KB1 and (Mx, M y ) KB2 A second evaluation unit 59 determines the X-translational degree of freedom (reference numeral 19-1), the Y-translational degree of freedom (reference numeral 19-2), and the rotational degree of freedom 0 from the measuring edges 18-1 and 18-2 of a respective target position of the respective circle center. Z (Reference symbol 20-3) of the position of the test object 12. As mentioned above, Fig. 4 shows a top view of the measuring table 14 with the measuring elements 16-1 and 16-2 arranged laterally to the test object 12. According to a further embodiment, the measuring elements can also be arranged in the edge region of the reflective surface 13 of the test object 12 (reference numerals 16-T and 16-2'). According to one embodiment, the measuring elements 16-T and 16-2' can be attached to the test object 12 by means of a mounting tool 84, as illustrated in Fig. 5 for the measuring element 16-1'. Fig. 5 shows a sectional view of the test object 12 along line VV in Fig. 4 in the area of ​​the measuring element 16-T. The test object 12 has a circular mounting recess 86 on its reflective surface 13 for mounting the measuring element 16-1', which has an insertion element in the center serving as a retaining element 88. The measuring element 16-T has a recess 90 for receiving the retaining element 88, so that the measuring element 16-1' can be placed onto the retaining element 88 and thus the test object 12 can be brought into engagement with the retaining element 88. The measuring element 16-1' is attached using the mounting tool 84.For this purpose, the measuring element 16-T is first placed in a recess of the mounting tool 84, and then the mounting tool 84 is inserted into the mounting recess 86 of the test object 12, i.e., the mounting tool 84 is secured by means of a plug connection between the mounting tool 84 and the mounting recess 86. Subsequently, an actuating button 92 is pressed, which is connected via a spring 94 to a sliding element 96, which places the measuring element 16-T onto the holding element 88. According to an alternative embodiment, the translational measurement shown in Figures 1 and 2 can also be performed using straight measuring edges as cutting apertures. With respect to a measuring edge, this can be achieved by inserting the measuring edge into the measuring beam 22-1 in various rotational positions relative to the z-axis, transverse to the measuring edge. By evaluating the edge positions measured in this way, the position of the test object 12 can be determined in one translational degree of freedom (in the insertion direction of the measuring edge) and one rotational degree of freedom (rotation relative to the z-axis). When measuring three straight measuring edges arranged at different locations on the measuring table 12, of which, for example, two have the same rotational position and the third is oriented transversely, in particular orthogonally, to them, the X-translational degree of freedom, the Y-translational degree of freedom, and the rotational degree of freedom can also be determined. Z Determine the position of the test object 12. More detailed information on the exemplary procedure for measuring straight measuring edges as cutting apertures can be found in DE 102017201 794 B4. Fig. 3 illustrates an embodiment of the aforementioned tilt measurement, which serves to determine at least one of the remaining rotational degrees of freedom 0 X and 0 y , preferably all remaining degrees of freedom of the position of the test object 12, namely the Z-translation degree of freedom (reference numeral 19-3), as well as the rotation degrees of freedom 0 X (Reference 20-1) and 0 y (Reference numeral 20-2) to be measured. The rotational degrees of freedom 0 X and 0 y Each relates to an axis of rotation which, in the xz section view according to Fig. 1, is aligned transversely to the measuring edge 18-1, which in turn runs parallel to the z-direction in the aforementioned section view. The beam interruption elements 70-1 and 70-2, already mentioned with reference to Fig. 1, are arranged on two opposite sides of the test object 12 on the measuring table 14. As can be seen in the top view of the measuring table 14 according to Fig. 4, in the illustrated embodiment these are arranged such that a connecting line 71 between the beam interruption elements 70-1 and 70-2 runs essentially through a center point of the test object 12. The second pair of beam interruption elements 72-1 and 72-2 is arranged such that their connecting line 73 is pivoted by 90° relative to the connecting line 71. The beam-interrupting elements 70-1 and 70-2 constitute a sighting arrangement in the form of a so-called "front and rear sight arrangement". Each of the beam-interrupting elements 70-1 and 70-2 represents a tower-like object comprising a cuboid 74 and a triangular prism 75 mounted on it, as illustrated in Fig. 3. The upper edge 76 of the triangular prism runs perpendicular to the connecting line 71 between the beam interruption elements 70-1 and 70-2, which is shown in Fig. 3 at the level of the edges 76. In the tilt measurement according to Fig. 3, the measuring table 14 is positioned relative to another measuring beam 22-2 such that the measuring beam 22-2 is arranged at a distance Az (reference numeral 77) above the connecting line 71 between the tips of the beam interruption elements 70-1 and 70-2 formed by the edges 76. The measuring beam 22-2 can be formed by the same light beam as the measuring beam 22-1 or by a different light beam.In the case where the two measuring beams 22-1 and 22-2 are generated by a single light beam, the relative orientation of the light beam generated by the measuring beam generation module 23 with respect to the measuring table 14 is changed compared to the translational measurement in order to perform the tilt measurement. This can be achieved by tilting the measuring beam generation module 23 and / or by tilting and correspondingly moving the measuring table 14 using the positioning system 24. In tilt measurement, the measuring table 14 is arranged in different tilt positions relative to the measuring beam 22-2, between which a tilt angle is determined by a tilting movement 79. <p bezüglich einer auf der Verbindungslinie 71 zwischen den Spitzen der Strahlunterbrechungselemente 70-1 und 70-2 liegenden Kippachse 78 variiert werden kann. Die Kippachse 78 ist in der dargestellten Ausführungsform parallel zur y-Achse ausgerichtet. Die Kippstellung, bei welcher der Messstrahl 22-1 den gleichen Abstand Az von den Kanten 76 der beiden Strahlunterbrechungselemente 70-1 und 70-2 aufweist, wird als Verkippungsgrundstellung 80-0 bezeichnet (cp= (po). Das Detektionsmodul 46 ist im Strahlengang des Messstrahls 22-1 an einem Messort angeordnet, der im Verlauf des Messstrahls 22-2 nach Passieren beider Strahlunterbrechungselemente 70-1 und 70-2 positioniert ist. Figure 3 shows two further tilting positions 80-1 and 80+1, namely a clockwise tilted position 80-1 and a counterclockwise tilted position 80+1. In position 80-1 (cp= <p-i) ist das linksseitige Strahlunterbrechungselement 70-1 mit seiner Spitze (Kante 76) derart in den Quer-schnitt des Messstrahls 22-2 eingefahren, dass 50% der Intensität des Messstrahls 22-1 vom Strahlunterbrechungselement 70-1 blockiert wird. Das heißt, das Detektionsmodul 46 detektiert in der Stellung 80-1 lediglich 50% der in der Verkippungsgrundstellung 80-0 gemessenen Maximalintensität. Analog dazu ist in der Stellung 80+1 (cp= epi ) das rechtsseitige Strahlunterbrechungselement 70-2 mit seiner Spitze (Kante 76) derart in den Querschnitt des Messstrahls 22-2, dass 50% seiner Intensität blockiert wird. Mit anderen Worten blockiert in den Verkippungsstellungen 80-1 und 80+1 jeweils eine der beiden Strahlunterbrechungselemente 70-1 bzw.70-2 partially affects the measuring beam 22-2 and the intensity measurement in the tilting positions 80-1 and 80+1 each concerns the radiation component of the measuring beam 22-2 which passes through both beam interruption elements 70-1 and 70-2. In the tilt measurement, a tilting movement 79 is performed in a first measurement process, in which the tilt angle cp is determined, starting from a tilted position with <p < cp-i , bei der die Intensität des Messstrahls 22-2 vollständig vom Strahlunterbrechungselement 70-1 blockiert wird, bis zu einer Kippstellung cp> cp-i, in which the intensity of the measuring beam 22-2 is completely blocked by the beam interruption element 70-2, is continuously changed. That is, during the tilting movement 79, the beam interruption element 70-1 is first moved out of the measuring beam 22-2 and at a later time the beam interruption element 70-2 is moved into the measuring beam 22-2.In other words, the two beam interruption elements 70-1 and 70-2 are moved by means of the tilting movement 79 such that an interruption state of the measuring beam 22-2 is first changed by the beam interruption element 70-1 and then by the beam interruption element 70-2. During the tilting movement 79, the respective intensity is recorded by the detector module 46 (see intensity diagram 82). The evaluation module 56 analyzes the edge profiles of the recorded intensity diagram 82 and determines the tilt angles cp-i and cp-i from this. <pi . Der Mittelwert der beiden Kippwinkel cp-i und <pi ergibt den Winkel (po in der Verkippungsgrundstellung 80-0, woraussich wiederum die Kippposition des Messtischs 14 in Bezug auf die y-Achse und damit der Rotationsfreiheitsgrad 0 y the position of the test object 12. Since the measuring beam 22-2 runs parallel to the x-axis, the measuring beam 22-2 is perpendicular to the rotational axis (y-axis) of the rotational degree of freedom 0 determined in the described measurement process. y irradiated. From the distance Acp between the tilt angles cp-i and epi, which is linear to the distance Az, the evaluation module 56 determines the translational degree of freedom Z of the position of the test object 12. In a further measurement process, the measuring table 14 is rotated by 90° with respect to the z-axis, so that the second pair of beam interruption elements 72-1 and 72-2 according to Fig. 4 is arranged in the measuring position according to Fig. 3 below the measuring beam 22-2. Subsequently, the tilt angles cp-i and epi for the beam interruption elements 72-1 and 72-2 are measured analogously to the first measurement process described above, and the mean value of cp-i and epi is used to calculate the angle of incidence. <pi wird der Rotationsfreiheitsgrad 0 X The position of the test object 12 is determined. In the subsequent measurement process, the measuring beam 22-2 is also directed perpendicular to the rotational axis (x-axis) of the rotational degree of freedom 0 determined in this way. X The distance Acp between the tilt angles cp-i and epi resulting from this measurement process can be used to validate the distance Az determined in the first measurement process, thus increasing the measurement accuracy of the translational degree of freedom Z. Each of the two measurement processes can be repeated with the measuring table 14 rotated by 180° with respect to the z-axis to improve measurement accuracy. That is, the respective measurement process is repeated with the beam interruption elements 70-1 and 70-2 or 72-1 and 72-2 in reverse order. According to one implementation variant, in each of the two measurement processes, the distance Az in the tilting base position 80-0 is changed. The tilting movement 79 is then performed again, and the corresponding tilt angles cp-i and epi are determined again. This is done for a plurality of distances Az. The additional consideration of the intensity curves determined in this way allows the determination of the degrees of freedom 0. X , 0y and Z with higher accuracy. Fig. 6 illustrates an optional rotation measurement, which, according to one embodiment, can be performed in addition to the translation measurement according to Fig. 1 and the tilt measurement according to Fig. 3. The rotation measurement allows the result of the tilt measurement to be compared with respect to the rotational degrees of freedom 0x and 0. y and possibly also checked with regard to the translational degree of freedom Z, or the result of the tilt measurement supplemented, for example if not all of the mentioned degrees of freedom were measured during the tilt measurement. X , 0y and Z are measured. According to another embodiment, the rotation measurement can also replace the tilt measurement; the measuring method then only uses the translation measurement and the rotation measurement. In the rotation measurement, the test object 12 is first adjusted based on the position values ​​determined during the translation measurement and, if applicable, the tilt measurement. These are also referred to below as adjustment values. According to one embodiment, the test object 12 is adjusted based on the position values ​​determined during the translation measurement for the degrees of freedom X, Y, and O. Z determined values ​​and advantageously additionally based on the degrees of freedom Z, 0 obtained during the tilt measurement X and 0 y The determined values ​​were adjusted. After adjustment, a third measuring beam 22-3 is directed onto a measuring point 97 in a central region of the reflective surface 13 of the test object 12, and the reflected radiation component (reflected measuring beam 22-3r) is detected by the detection module 46. According to one embodiment, the central region of the reflective surface 13 is understood to be an area at the center of the reflective surface 13 which comprises less than 30%, in particular less than 10%, of the area of ​​the reflective surface 13. Alternatively, the central region can be defined, for example, by a circle around the geometric center of the reflective surface 13 with a radius of less than 50%, in particular less than 30%, of the radius of the reflective surface 13 in the case of a substantially circular reflective surface.According to a further embodiment, the central area is understood to be an area in the center of the reflective surface 13 in which the mirror curvature is low enough that reflected measuring beams 22-3r generated at the different points of the central area do not deviate from each other by more than 0.5°, in particular not by more than 0.05°. The measuring beam 22-3 can be formed by the same light beam as the measuring beams 22-1 and / or 22-2, or by a different light beam. If the two measuring beams 22-1 and 22-3 are generated by a single light beam, the light beam generated by the measuring beam generation module 23 is repositioned relative to the measuring table 14 for the rotation measurement compared to the translation measurement. This can be achieved by means of the measuring beam generation module 23 and / or the measuring table 14 using the positioning system 24. During rotation measurement, the angle of incidence is measured. <t>(Reference numeral 41) for a first measurement is initially set to a first value of less than 5°, for example 1.5°. Analogous to the above explanation with reference to Fig. 1, the angle of incidence <t>the deviation angle of the incoming measuring beam 22-3 from the perpendicular incidence on the reflective surface 13 is defined. The detection module 46 is positioned in the beam path of the measuring beam 22-3r reflected from the reflective surface 13. The measuring table 14, and thus also the test object 12, is then rotated about a rotation axis 98 that is aligned parallel to the z-axis, i.e., tilted at approximately 90° to the reflective surface 13 of the test object 12. A rotational movement is thus performed, during which an impact position 100 of the reflected measuring beam 22-3r is measured at various positions i of the rotational movement (i.e., different rotation angles p) on a two-dimensional detection surface 47 of the detection module 46, and the position coordinates (xDet,yoet)i of the impact positions 100 on the detection surface 47 are thereby determined. The axis of rotation 98 preferably passes through the point of impact or measuring point 97 of the measuring beam 22-3 on the reflective surface 13. In the present example, the respective measurement of the impact position is carried out in 30° increments of the rotational movement, i.e., for example, at rotational positions of p = 0°, 30°, 60°, etc. The measurements are carried out for further angles of incidence. <t>, in the present case for the angles of incidence 10° and 20°, repeated. Thus, for each rotation position, three measured values ​​102 of the impact position 100 are available. The aforementioned exemplary angles of incidence <t>These values ​​apply when test object 12 is configured as a normal incidence mirror. In the case of a mirror operated at grazing incidence (also known as a grazing incidence mirror), the following values ​​apply to the angle of incidence: <t>Values ​​between 50° and 89° are used. Fig. 6 shows, in a drawing inset 104, the measured values ​​102 determined for the various rotation positions. These are distributed circularly around the origin (0 mm, 0 mm) of the detection surface 47. For illustrative purposes, Fig. 7 shows the beam paths of the measuring radiation 22-4, which form the basis for the x-coordinates of the measured values ​​102-0, 102-90, 102-180, and 102-270 in the drawing inset 104 of Fig. 6 for the rotation positions p = 0°, 90°, 180°, and 270° in the x-z plane. A tilting of the test element 12 in the rotation position p = 0° is shown. X (i.e., tilting about the x-axis) is assumed with respect to a reference plane. In rotation positions p = 0° and p = 180°, the reflected measuring beam 22-3r strikes approximately the center of the detection surface 47 with respect to the x-coordinate axis, i.e., at XDet = 0 mm (see measured values ​​102-0 and 102-180 according to Fig. 6). In rotation positions p = 90° and p = 270°, however, the point of impact of the reflected measuring beam 22-3r on the detection surface 47 is shifted by approximately 1 mm in the +x direction and -x direction, respectively, in the illustrated example (see measured values ​​102-90 and 102-270 according to Fig. 6). The totality of the determined measured values ​​102, i.e. the position coordinates (xDet,yDet)i of the impact positions 100 at all i measured rotation positions as well as all measured angles of incidence <t>are fitted at impact positions which are to be expected with an optimally adjusted test object 12 (in the present case the coordinate origin (0mm, 0mm) of the detection surface 47), whereby the two rotational degrees of freedom 0 X and 0 y and the translational degree of freedom Z serve as fitting variables. As a result of the fitting process, the position of the test object 12 in the rotational degrees of freedom 0 are thus determined. X and 0 y as well as the translational degree of freedom Z. If the test specimen is now adjusted based on the determined degrees of freedom, the corrected measured values ​​108 shown in the drawing inset 104 are obtained when the impact positions 100 are measured again. Preferably, the adjustment values ​​set at the beginning of the rotation measurement are taken into account in the fitting procedure. According to one embodiment, the measuring beam 22-3 is directed onto further measuring points 97 in the central area of ​​the reflective surface 13 described above, and the measurement described above is performed. According to another embodiment, all measuring points used for this purpose have the same distance from the axis of rotation 98, or a distance from the axis of rotation 98 that varies by a maximum of 10%. This would allow the degrees of freedom 0 X , 0 y and Z can be measured with higher accuracy. According to an alternative embodiment, the measured values ​​of the impact positions 100 are only recorded for one angle of incidence. <t>measured. The fitting evaluation then only yields 0 rotational degrees of freedom. X and 0 y For the translational degree of freedom Z, the result of the tilt measurement according to Fig. 3 can then be used, or a so-called height scan can be performed. Such a height scan is known to those skilled in the art, for example, from paragraph

[0018] known from DE 102017201 794 B4 (method of height adjustment). Figure 8 schematically illustrates an exemplary embodiment of a reflectometer 200 for measuring a reflection property of the test object 12, into which the measuring device 10 according to Figure 1 is integrated. The exact configuration of the reflectometer 200 is to be understood as exemplary; other configurations are possible. The reflectometer 200 is configured to detect a reflectance at a variety of wavelengths in the EUV spectral range, for example, at wavelengths of approximately 13.5 nm or approximately 6.8 nm. Furthermore, the reflectometer 200 is designed to set a predetermined angle of incidence of the EUV radiation onto the reflective surface 13. The test object 12 is, for example, a mirror for a projection exposure system for EUV microlithography. The reflectometer 200 includes a measuring beam generation module 223 for generating a measuring beam 222, which can be identical to the measuring beam generation module 23 of the measuring device 10 according to Fig. 1. The measuring beam generation module 223 includes a radiation source 216 for electromagnetic radiation in the EUV spectral range. The radiation source 216 comprises, for example, a laser-produced plasma (LPP) source with a pulsed laser 218, whose laser beam 220 generates a plasma on a gold target 224. The plasma emits a quasi-continuous spectrum of electromagnetic radiation as an emission spot in the EUV range, hereinafter referred to as EUV radiation 226. Furthermore, the measurement beam generation module 223 includes a monochromator 227 for adjusting or selecting the wavelength of the measurement beam 222 directed at the test object 12. A portion of the EUV radiation 226 emitted by the emission spot passes through an entrance aperture 228 of the monochromator 227 and strikes a front plane-elliptical mirror 230. Plano-elliptical mirrors are defined as mirrors with a reflecting surface that is planar in one direction and elliptical in a substantially perpendicular direction. The front mirror 230 directs the EUV radiation 226 onto a reflection grating 232 and is configured such that the emission volume of the radiation source 216 is imaged onto the test object 12 with respect to a first plane of the EUV radiation 226 in the y-direction. This preferably results in an enlargement of the emission spot and a reduction of the beam divergence. The reflection grating 232 has a truss structure with a concave circular cylindrical surface. The surface is thus planar in one direction and circular in an essentially orthogonal direction. The truss structure is provided with grating lines of a constant line density, e.g., 1600 line pairs per mm. When a light beam is diffracted, it is focused along a focal line parallel to the planar direction or the y-axis. The reflection grating 232 diffractes and reflects the EUV radiation 226 in a wavelength-dependent manner such that, in the beam path in front of a rear plano-elliptical mirror 234, a wavelength-dependent intermediate focus is located with respect to a second plane parallel to the xz-plane. An exit slit 236 is arranged at this intermediate focus, which allows only a very small wavelength range of the EUV radiation 226 to pass through. The slit width of the exit slit 236 is adjustable and determines the measurement spot size on the test object 12 and the spectral resolution. The rear mirror 234 is configured and arranged such that the exit slit is imaged perpendicular to the y-axis onto the test object 12. Preferably, the rear mirror 234 is configured such that the exit slit is also magnified and imaged onto the test object 12 with reduced beam divergence. The EUV radiation 226 emitted from the rear mirror 234 onto the surface of the test object 13 is referred to as the measurement beam 222 mentioned above. The intensity of the radiation 238 of the measuring beam 222 reflected by the test object 12 is detected by a detection module 246, which can be identical to the detection module 46 of the measuring device 10 described with reference to Fig. 1. A small portion of the radiation of the measuring beam 222 is directed by a beam splitter 242, located in the beam path upstream of the test object 12, onto a reference detector 244. Using the detected intensities of the incident measuring beam 222 and the reflected radiation 238, the reflectance of the test object 12 is determined with respect to a set angle and location of incidence on the test object 12, as a function of the wavelength of the measuring beam 222 defined by the monochromator 227. The reflectometer 200 is arranged in a vacuum chamber (not shown in the drawing). The entire EUV beam path from the radiation source 216 to the detection module 246 thus runs within a vacuum of, for example, approximately 2 x 10⁻⁶ arcminutes. 6 mbar. The test object 12 is also located in the vacuum chamber and is attached to the measuring table 14. As already explained above with reference to Fig. 1, the measuring table 14 can be positioned in all six rigid body degrees of freedom. The measuring device 10 enables the precise adjustment of the positioning of the measuring table 14 and thus of the test object 12. The measuring table 14 therefore allows the adjustment of the point and angle of incidence of the measuring beam 22 for the reflectometer measurement. The foregoing description of exemplary embodiments, embodiments, or variants is to be understood as illustrative. The disclosure thereby enables the person skilled in the art, on the one hand, to understand the present invention and its associated advantages, and, on the other hand, also encompasses, in the understanding of the person skilled in the art, obvious modifications and alterations of the described structures and methods. Therefore, all such modifications and alterations, insofar as they fall within the scope of the invention as defined in the appended claims, as well as equivalents, are to be covered by the protection of the claims. List of reference numerals 10 Measuring device 12 test objects 13 reflective surface 14 Measuring table 16-1, 16-2 measuring elements 16-T, 16-2' measuring elements 17-1, 17-2 Measuring apertures 18-1,18-2 measuring edges 19 translational degrees of freedom 20 rotational degrees of freedom 21 surface 22-1 Measuring beam 22-1 r reflected radiation fraction 22-2 Measuring beam 22-3 Measuring beam 22-3r reflected measuring beam 23 Measuring beam generation module 24 Positioning system 26 x-translation 28 y-translation 30 z-translation 32 Tilt with respect to the y-axis 34 Rotation with respect to the z-axis 36 Translational movement of the measuring table 38 Effective translational movement of the measuring beam 40 Drawing insert 41 Angle of incidence 42 Path of the measuring beam 44v front intersection 44h rear intersection point 46 detection module 47 detection area 48 Drawing insert 50 Intensity diagram 52 Drawing insert 53 Cross-section of the measuring beam 54-1, 54-2 Intersection coordinates 56 Evaluation module 58 first evaluation unit 59 second evaluation unit 60 mathematical description 62 modified circle 64 determined circle center 66-1, 66-2 geometric center of gravity 68 Target position 70-1, 70-2 first pair of beam interruption elements 71 connecting line 72-1, 72-2 second pair of beam interruption elements 73 connecting line 74 cuboids 75 Triangular prism 76 edge 77 distance 78 tipping axle 80-0 Tilt basic position 80-1 Tilting position 80+1 tilt position 82 Intensity diagram 84 Assembly tools 86 Mounting recess 88 retaining element 90 Recess 92 Actuating button 94 springs 96 Shear element 97 measuring point 98 Rotation axis 100 impact position 102 Measurements of the impact point 102-0 Measurements for p = 0° 102-90 Measurements for p = 90° 102-180 Measurements for p = 180° 102-270 Measurements for p = 270° 104 Drawing insert 106 Reference plane 108 corrected measurements 200 reflectometers 216 Radiation source 218 pulsed laser 220 laser beam 222 Measuring beam 223 Measuring beam generation module 224 Gold target 226 EUV radiation 227 Monochromator 228 Entrance aperture 230 plane elliptical mirrors 232 Reflection gratings 234 plane elliptical mirror 236 Exit gap 238 reflected radiation 242 beam splitters 244 Reference detector 246 Detection module< / t> < / t> < / t> < / t> < / t> < / t> < / t> < / t> < / t> < / t> < / t> < / t> < / t> < / t> < / t> < / t>

Claims

Claims 1. Procedure for determining the position of a test object (12) comprising the steps: - Determining the position of the test object in at least one translational degree of freedom (19-1; 19-2) transverse to a first measuring beam by means of a translational measurement in which a measuring edge (18-1; 18-2) of a measuring element (16-1; 16-T; 16-2; 16-2') associated with the test object is moved by means of a relative translational movement (38) with respect to the first measuring beam (22-1) through a cross-section (53) of the first measuring beam and at several positions of the translational movement an intensity of the first measuring beam is measured at a measuring location (23) downstream of the measuring element, as well as - Determining the position of the test object in at least one rotational degree of freedom (20-1; 20-2) with respect to an axis of rotation which is oriented transversely to the first measuring beam, by means of a tilt measurement, in which at least one beam interruption element (70-1; 70-2; 71-1; 72-2) associated with the test object is moved by means of a tilting movement (79) relative to a further measuring beam (22-2) directed transversely to the axis of rotation (78) of the rotational degree of freedom such that an interruption state of the further measuring beam is changed, and an intensity of a radiation component of the further measuring beam which passes the beam interruption element is measured at different positions (80-1, 80-0, 80+1) of the tilting movement, wherein the first measuring beam and the further measuring beam are generated by different light beams or by a uniform light beam in different orientations with respect to the test object.

2. Method according to claim 1 , where the test object (12) is an optical element.

3. Method according to claim 1 or 2, wherein the test object (12) is assigned a further measuring element (16-2; 16-2') with a further measuring edge (18-2), the translation measurement further includes a measurement at the further measuring edge and the position of the test object in a further rotational degree of freedom is determined by means of the translation measurement.

4. Method according to any of the preceding claims, where the measuring edge (18-1; 18-2) of the measuring element is curved.

5. Method according to any of the preceding claims, in which, during translational measurement, the measuring edge (18-1; 18-2) is moved with several relative translational movements to the first measuring beam such that a respective path (42) of the first measuring beam traveled in the plane of the measuring element during the different translational movements intersects the measuring edge at a respective location (44).

6. Method according to claim 5, in which the various translational movements (36) run parallel and / or perpendicular to each other.

7. Method according to any of the preceding claims, in which the coordinates (54-1 ; 54-2) of several intersection points (44) of the measuring edge with a path (42) traveled by the measuring beam in the plane of the measuring element are determined from the intensity values ​​(50) measured during the translation measurement, a mathematical description (60) of the course of the measuring edge is fitted to the determined coordinates, wherein a fitting result includes a geometric center of gravity (66) of the course of the measuring edge, and the position of the test object in two translational degrees of freedom is determined from a deviation of the geometric center of gravity from a target position (68).

8. Method according to claim 7, wherein the measuring edge has a circular profile and the geometric center of gravity encompassed by the fitting result is the center of the circle (66) of the profile of the measuring edge.

9. Method according to claim 7 or 8, in which the mathematical description of the course of the measuring edge includes a modified circle equation (60) in which deviations from the ideal circle equation due to an angle of incidence (41) of the first measuring beam with respect to the plane of the test object are taken into account.

10. Method according to any of the preceding claims, in which the first measuring beam (22-1) and the further measuring beam (22-2) are generated by a uniform light beam in different orientations with respect to the test object (12).

11. Procedure according to any of the preceding claims, in which the object being measured is attached to the test object (12) by means of a mounting tool (84), by first attaching the mounting tool to the test object and then engaging the test object with a holding element (88) of the test object by means of the mounting tool.

12. Method according to any of the preceding claims, in which a further translational degree of freedom (19-3) is determined by means of the tilt measurement.

13. Method according to any of the preceding claims, in which, during the tilt measurement, a pair of beam interruption elements (70-1, 70-2; 72-1, 72-2) are arranged on opposite sides of the test object and, during the tilting movement (79), one of the beam interruption elements (70-1; 72-1) is moved out of the further measuring beam (22-2) and, at another time, the other of the beam interruption elements (70-2; 72-2) is moved into the further measuring beam.

14. Method according to one of claim 13, in which the tilting movement (79) includes a tilting base position (80-0) in which the further measuring beam (22-2) passes the two beam interruption elements (70-1, 70-2; 72-1, 72-2) at the same distance (77), after the intensity measurements during the tilting movement the distance in the tilting base position is changed and further intensity measurements are carried out during a further tilting movement with the changed distance.

15. Method according to claim 13 or 14, wherein the intensity measurements in the tilt measurement comprise a measurement of an intensity of a radiation component of the further measuring beam (22-2) passing through both radiation interruption elements (70-1, 70-2; 72-1, 72-2), wherein the passing radiation component is generated at positions of the tilting movement (79) where one of the two beam interruption elements partially blocks the further measuring beam.

16. Method according to any one of claims 12 to 14, in which, during the tilt measurement, a further pair of beam interruption elements (72-1, 72-2) are arranged on opposite sides of the test object such that a connecting line (73) between the beam interruption elements (72-1, 72-2) of the further pair is pivoted relative to a connecting line (71) between the beam interruption elements (70-1, 70-2) of the first pair, and wherein the position of the test object in two further rotational degrees of freedom (20-1, 20-2) is measured by means of the tilt measurement.

17. Method according to any of the preceding claims, which further includes a rotation measurement in which a third measuring beam (22-3) is reflected at a reflective surface (13) of the test object (12), the test object is moved by means of a rotational movement (34) about a rotational axis (98) oriented transversely to the reflective surface and for the different positions of the rotational movement an impact position (100) of the reflected measuring beam on a detector is measured.

18. Method according to claim 17, in which the position of the test object in the at least one rotational degree of freedom (20-1; 20-2) is determined from the measured values ​​(102) of the impact positions by fitting the measured values ​​to expected impact positions, wherein the at least one rotational degree of freedom is defined as the fitting variable.

19. Measuring device (10) for determining the position of a test object (12) with: - a measuring table (14) for holding the test object and a measuring element (16-1; 16-T; 16-2; 16-2') with a measuring edge (18-1 ; 18-2) and at least one beam interruption element (70-1; 70-2; 71-1; 72-2), - a measurement beam generation module (23) for generating a first measurement beam (22-1) and a further measurement beam (22-2) from different light beams or a uniform light beam in different orientations with respect to the test object, - a positioning system (24) for the relative positioning of the measuring element and the first measuring beam to each other and of the beam interruption element and the second measuring beam to each other, wherein the positioning system is configured to, to move the measuring edge by means of a relative translational movement (38) to the first measuring beam through a cross-section (53) of the first measuring beam, as well as to move the beam interruption element relative to the further measuring beam by means of a tilting movement (79) such that an interruption state of the further measuring beam is changed, - a detection module (46) for measuring an intensity (50) of the first measuring beam at several positions of the translation at a measuring location downstream of the measuring element, as well as for measuring an intensity (82) of a radiation component of the further measuring beam which passes the beam interruption element, at different positions (80-1, 80-0, 80+1) of the tilting movement, as well as - an evaluation module (56) configured to determine the position of the test object in at least one translational degree of freedom (19-1; 19-2) from the measured intensities of the first measuring beam and to determine the position of the test object in at least one rotational degree of freedom (20-1; 20-2) arranged transversely to the direction of entry of the further measuring beam from the intensities measured at the different positions of the tilting movement.

20. Reflectometer (200) for determining a reflection property of a test object (12) with a measuring device (10) according to claim 19 for determining a position of the test object.

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