Measuring assembly for determining the position of a component

Abstract

The invention relates to a measuring assembly (100) for determining the position of a movable component in a microlithography system, comprising at least one optical resonator (101) having a first optical element (102) which is designed to generate a standing wave with a second optical element (103) of the resonator (101), and having a reflector (104) which forms the measurement target of the component, is movably arranged in the beam path between the first optical element (102) and the second optical element (103), and has a first reflective surface (105) and a second reflective surface (106) which is inclined with respect to the first reflective surface (105). At least one of the two optical elements (102, 103) is toroidal or has at least one toroidal sub-surface (109).

Description

[0001] Measuring arrangement for determining the position of a component

[0002] The invention relates to a measuring arrangement for determining the position and / or distance of a movable component, in particular in a lithography system, for example in a photolithography system, comprising at least one optical resonator having a first optical element configured to generate a standing wave with a second optical element of the resonator. The resonator further comprises a reflector forming the measurement target of the component, which is movably arranged in the beam path between the first optical element and the second optical element and has a first reflection surface and a second reflection surface arranged at an angle to the first reflection surface.The invention further relates to a projection exposure system, an illumination system for the lithography system, a lithography system, an inspection system, in particular for masks or wafer stages, a measuring machine and a coordinate measuring machine.

[0003] Lithography systems are used to create extremely fine structures, particularly on semiconductor devices or other microstructured components. Microstructured components are understood to be components or devices with microstructures and / or nanostructures. These structures are produced using a projection exposure system. The operating principle of these systems is based on creating extremely fine structures down to the nanometer range by means of a generally reduced-size image of structures on a mask, a so-called reticle, on an element to be structured, a so-called wafer, which is provided with photosensitive material. The minimum dimensions of the created structures depend directly on the wavelength of the light used. This light is shaped in an illumination optics for optimal illumination of the reticle.In recent times, light sources with an emission wavelength in the range of a few nanometers, for example between 1 nm and 120 nm, and particularly in the range of 13.5 nm, have been increasingly used. This wavelength range is also referred to as the EUV range. In addition to systems operating in the EUV range, microstructured components are also manufactured using the market-established DUV systems with a wavelength between 100 nm and 300 nm, particularly 193 nm. With the demand for ever smaller structures, the requirements for optical correction in the systems have also increased. With each new generation of projection exposure systems in the EUV or DUV range, throughput is increased to improve cost-effectiveness.

[0004] In the operation of microlithographic projection exposure systems, in which the mask and wafer are usually moved relative to each other in a scanning process, the positions of the mirrors, some of which are movable in all six degrees of freedom, must be adjusted and maintained with high precision both to each other and to the mask or wafer in order to avoid or at least reduce aberrations and the associated impairments of the imaging result or shifts of the image.

[0005] Various approaches are known in the state of the art for measuring the position of individual mirrors, as well as the wafer or wafer stage and the reticle plane. In addition to interferometric measurement setups, frequency-based position measurement using an optical resonator is also known.

[0006] This is described, for example, in DE 10 2012 212 663 A1. This discloses a resonator in the form of a Fabry-Perot resonator with two resonator mirrors, of which the first resonator mirror is attached to a reference element in the form of a measuring frame firmly connected to the housing of the projection lens of the projection exposure system, and the second resonator mirror (as a "measurement target") is attached to a mirror whose position is to be measured. The actual distance measuring device comprises a radiation source whose optical frequency is tunable, which generates coupling radiation that passes through a beam splitter and is coupled into the optical resonator. The radiation source is controlled by a coupling device such that the optical frequency of the radiation source is tuned to the resonant frequency of the optical resonator and thus coupled to this resonant frequency.The input radiation coupled out via a beam splitter is analyzed using an optical frequency measuring device, which can, for example, include a frequency comb generator for highly accurate determination of the absolute frequency. If the position of the EUV mirror changes in the x-direction, the resonance frequency of the optical resonator changes along with the distance between the resonator mirrors, and thus - due to the coupling of the frequency of the tunable radiation source to the resonance frequency of the resonator - also the optical frequency of the input radiation, which in turn is directly recorded by the frequency measuring device. Alternatively, an ultrastable light source can be used instead of a tunable light source. The frequency of the laser is then adjusted using a frequency shifter, which acts as an electro-optical modulator (e.g.as an IQ modulator), shifted and tracked to the resonance frequency of the optical resonator by means of a control loop, in particular by means of the Pound Drever Hall method.

[0007] A key factor for the functionality of an optical resonator for distance measurement is, on the one hand, that the measuring beam can complete as many revolutions as possible within the optical resonator (without leaving the cavity formed by the resonator) so that eigenmodes can develop in the resonator. Another key factor is the ability to couple the external radiation field (“input coupling field”) present at the entrance to the resonator path to the mode field of the optical resonator (“resonator field”). The coupling efficiency characteristic of this coupling is defined by the overlap integral between the input coupling field and the resonator field, so that to achieve high coupling efficiency, the input coupling field and the resonator field must match as closely as possible in all relevant parameters.

[0008] In practice, when using an optical resonator for distance measurement when measuring the position of a component or a mirror, problems can arise because movements of the measuring target arranged on the mirror can occur not only along the actual measurement direction, but also in other of the six degrees of freedom. Such (parasitic) movements that do not occur along the measurement direction, e.g., intentional or unintentional tilting or lateral displacement of the measuring target, can lead to a "wandering" of the main beam, on which the resonator modes are "threaded," in position and angle, with the result that sufficient coupling of the resonator field to the coupling field is no longer ensured.

[0009] Given the high demands placed on the beam direction deviation, ensuring that tilts or lateral displacements of the measurement target do not become effective in frequency-based position determination represents a demanding challenge.

[0010] Furthermore, WO 2019 / 223968 A1 discloses various resonators for detecting the position of a moving component.

[0011] Furthermore, the German patent application filed under application number 102022210369.6 discloses a resonator with a parallel beam path and a multi-part retroreflector.

[0012] It is therefore the object of the present invention to provide a measuring arrangement, a projection exposure system, an illumination system, a lithography system, an inspection system, a measuring machine and a coordinate measuring machine which overcome or at least reduce the above-mentioned disadvantages.

[0013] The problem concerning the measuring arrangement is solved by a measuring arrangement according to the features of claim 1. The problem concerning the projection exposure system is solved by a projection exposure system with the features of claim 16. The problem concerning the illumination system is solved by an illumination system with the features of claim 17. The problem concerning the lithography system is solved by a lithography system with the features of claim 18. The problem concerning the inspection system is solved by an inspection system with the features of claim 19. The problem concerning the measuring machine is solved by the measuring machine with the features of claim 20. The problem concerning the coordinate measuring machine is solved by a coordinate measuring machine with the features of claim 21. Advantageous embodiments with expedient further developments are specified in the subclaims.

[0014] The measuring arrangement is characterized in particular by the fact that at least one of the two optical elements is toric or at least has a toric partial surface. The inventive design of the optical resonator enables stable coupling into the mode with a simultaneous lower number of reflections and lower complexity of the optics in the measuring arrangement. In addition, the resonator is less sensitive to tilting. The reflector is aligned in such a way as to direct the light beam from one of the optical elements to the other of the optical elements. The resonator is

[0015] In particular, it is provided that the resonator is designed in such a way that one complete revolution of the light beam in the resonator consists of exactly six reflections. This reduces the number of reflections required and thus the effort required for adjustment as well as the requirements for the reflectivity of the layers, while still maintaining a comparatively high insensitivity to tilting. One revolution of the resonator is understood to be the number of reflections necessary for the light to strike the coupling element again and be reflected there. In this case, the coupled-in light from the first optical element strikes the first reflective surface of the reflector. There it is reflected for the first time and then reflected for a second time on the second reflective surface of the reflector onto the second optical element. From the second optical element, the light beam is reflected for the third time onto the second reflective surface of the reflector.From the second reflection surface, it is reflected back to the first reflection surface for the fourth time. From the first reflection surface, the light beam is reflected back to the first optical element for the fifth time. Finally, the light beam is reflected back to the first reflection surface by the first optical element for the sixth time.

[0016] Furthermore, it is preferred if the first optical element is formed as a mirror. The mirror is preferably formed to be highly reflective with a reflection of over 95% and preferably has a highly reflective coating. In this context, it is particularly preferred if the first optical element is formed as a toric mirror or as a mirror with a toric partial surface. Thus, in one embodiment, at least the first optical element is formed as the optical element which is formed toric or has at least one toric partial surface. Alternatively, the first optical element can also have a plurality of toric partial surfaces, in particular a plurality of mutually differing optical partial surfaces.

[0017] The radius of the first optical element is preferably selected such that the beam cross-section on the first optical element in both propagation directions (the x and y directions) is at least approximately the same, or such that the deviation is less than 25%, preferably less than 20%, particularly preferably less than 10%. This enables simplified coupling of the light beam into the resonator, particularly when using an optical fiber.

[0018] Alternatively, it is advantageous if the first optical element is formed as a lens, in particular as a converging lens. In this context, the lens has a toric partial surface at least on one side of the lens. Furthermore, it is advantageous in this context if a surface or a partial surface of the lens is formed with a mirror coating, in particular with a high level of reflection. In particular, it is advantageous if the side of the lens has a toric partial surface that is mirrored or at least partially mirrored. However, alternatively or additionally, a surface of the lens formed without a mirror coating can also have a toric partial surface.

[0019] Furthermore, it is preferred if the second optical element is formed as a mirror. It is particularly advantageous if the second optical element is formed as a toric or as a cylindrical mirror. Thus, additionally or alternatively, the second optical element can be formed as the optical element which is formed toric or at least has a toric surface. Particularly preferably, both the first optical element and the second optical element are formed toric or have a toric surface. It is very particularly preferred if the first optical element is formed toric and the second optical element is formed cylindrical.To make the resonator even more insensitive to tilt, it is advantageous if the cylinder radius of the second optical element approximately corresponds to the distance between the second optical element and the measurement target, with the deviation being less than 20%, preferably less than 10%, and particularly preferably less than 5%. It is preferred that the center of curvature of the second optical element be located on the measurement target or at a distance of at most 20%, preferably less than 10%, and particularly preferably less than 5% of the distance between the second optical element and the measurement target.

[0020] At smaller measurement distances, a lateral offset of the measurement target can lead to an increasingly larger lateral offset of the mode on the first optical element. Therefore, it is particularly preferred if the first partial beam path arranged between the first optical element and the first reflection surface and the second partial beam path arranged between the second reflection surface and the second optical element run parallel, or if the deviation from parallelism of the partial beam paths is less than 15°, preferably less than 10°, and particularly preferably less than 5°.

[0021] Furthermore, the reflector is preferably formed as two plane mirrors spaced apart from one another and arranged at an angle to one another, with the first plane mirror having the first reflection surface and the second plane mirror having the second reflection surface. The plane mirrors can also form a roof edge mirror.

[0022] Alternatively, it is also possible that the reflector is formed as a prism and that the reflection surfaces are formed as totally reflecting surfaces of the prism.

[0023] Alternatively or additionally, in order to make the resonator less sensitive to tilting of the measurement target, it is advantageous if the second optical element is arranged concentrically or at least approximately concentrically with respect to one of its principal curvatures to a tilting point located on a tilting edge of the two reflecting surfaces. The tilting edge of the reflecting surfaces is the edge at which the two reflecting surfaces or plane mirrors aligned at an angle to one another meet, or would virtually meet, i.e. the (virtual) meeting edge of the two reflecting surfaces. The tilting point is any point on this edge, preferably a tilting point located centrally or approximately centrally on the edge. Approximately concentric means that a deviation from the concentricity is less than 20%, preferably less than 10%, particularly preferably less than 5%.Furthermore, it is advantageous if the second optical element is formed as a cylindrical mirror and is arranged such that an axis of curvature of the second optical element intersects the tilting edge of the reflection surfaces. It is advantageous if the distance between the axis of curvature of the second optical element and the tilting edge is less than 20%, preferably less than 15%, and particularly preferably less than 10% of the radius of curvature of the second optical element 103.

[0024] The projection exposure system of a lithography system according to the invention has at least one measuring arrangement according to the invention. The at least one measuring arrangement is configured to detect the position or distance of a component of the projection exposure system. The component can be, in particular, a movable or immovable optical element, but also any other component of a projection exposure system, for example, support structures or actuators. For this purpose, the at least one measuring arrangement is or can be connected directly or indirectly to the component to be measured. The advantages and embodiments mentioned for the measuring arrangement also apply to the projection exposure system comprising at least one measuring arrangement.

[0025] The measuring arrangement according to the invention can also be used for a projection lens for a projection exposure system, which has at least one measuring arrangement according to the invention. The at least one measuring arrangement is configured to detect the position or distance of a component of the projection lens. The component can in particular be a movable or immovable optical element, but also any other component of a projection lens, for example also support structures or actuators. For this purpose, the at least one measuring arrangement is or can be connected directly or indirectly to the component to be measured. The advantages and embodiments mentioned for the measuring arrangement also apply to the projection lens comprising at least one measuring arrangement. The illumination system according to the invention for a lithography system has at least one measuring arrangement according to the invention.This is designed to detect the position or distance of a component. The component can in particular be an optical element or a support structure. For this purpose, the at least one measuring arrangement is or can be connected directly or indirectly to the component to be measured. The illumination system of a lithography system comprises in particular a light source which is designed to generate light in an EUV or DUV wavelength range and a plurality of optical elements which are designed to redirect the light generated by the light source and couple it into the projection exposure system. The advantages and embodiments mentioned for the measuring arrangement also apply to the illumination system comprising at least one measuring arrangement.

[0026] The lithography system according to the invention has at least one measuring arrangement according to the invention. The at least one measuring arrangement is configured to detect a position or a distance of a movable or immovable component. The component can be an optical element, a support structure, an actuator, a wafer stage, or a mask. However, the component can also be any other component of a lithography system whose position or distance from a reference must be measured. For this purpose, the at least one measuring arrangement is or can be connected directly or indirectly to the component to be measured. In particular, it is preferred if several measuring arrangements are assigned to each component in order to detect the position or a distance along several degrees of freedom. The advantages and embodiments mentioned for the measuring arrangement also apply to the lithography system comprising at least one measuring arrangement.

[0027] The inspection system according to the invention for checking an optical element or a wafer stage or a mask has at least one measuring arrangement according to the invention. The measuring arrangement is designed to detect the position or distance of a component, for example an optical element of a wafer stage or a mask. An evaluation unit is preferably present which compares the detected positions or distances, in particular of structures of the component, with predetermined distances or positions of the structures or components and initiates measures in the event of a deviation by a predetermined limit value. For this purpose, the at least one measuring arrangement is or can be connected directly or indirectly to the component to be measured. The advantages and embodiments mentioned for the measuring arrangement also apply to the inspection system comprising at least one measuring arrangement.An example of such an inspection system for mask or wafer inspection (without the measuring system according to the invention) is known from the document DE 102012205181 A1, the entire content of which is incorporated into the present application by reference.

[0028] The measuring machine according to the invention for detecting the position, geometry, or shape of a component has at least one measuring arrangement according to the invention. The at least one measuring arrangement is preferably connected directly or indirectly to the component. The measuring machine can be used in particular in the context of manufacturing technology or industrial metrology in mechanical engineering, for example in the automotive industry or aerospace engineering. The at least one measuring arrangement is or can be connected directly or indirectly to the component to be measured. The advantages and embodiments mentioned for the measuring arrangement also apply to the measuring machine comprising at least one measuring arrangement.

[0029] The coordinate measuring machine according to the invention has at least one measuring arrangement according to the invention. Coordinate measuring machines are used for inspecting or measuring components, wherein the component is usually scanned and distances or positions are determined based on the scanning. For this purpose, an optical system and a movable frame structure and / or a high-precision positioning system are provided, which supports the component or object to be inspected. The measuring arrangement is preferably directly or indirectly connected to this movable component, i.e., frame structure or positioning system. By means of the at least one measuring arrangement, the position or distance of the movable component can be determined, whereby the scanning of the object can be controlled. Furthermore, a measuring arrangement can also be used to detect the distance or position of the component itself and thus to inspect it.The advantages and embodiments mentioned for the measuring arrangement also apply to the coordinate measuring machine comprising at least one measuring arrangement. An example of such a coordinate measuring machine (without the measuring arrangement according to the invention) is known from the publication DE10 2019 213 794A1, the entire content of which is incorporated by reference into the present application.

[0030] The invention can also be used in a measuring machine for detecting the position, geometry, or shape of a component. The measuring machine then has at least one measuring arrangement according to the invention. The at least one measuring arrangement is preferably connected directly or indirectly to the component. The measuring machine can be used in particular in the context of manufacturing technology or industrial metrology in mechanical engineering, for example in the automotive industry or aerospace engineering. The at least one measuring arrangement is or can be connected directly or indirectly to the component to be measured. The advantages and embodiments mentioned for the measuring arrangement also apply to the measuring machine comprising at least one measuring arrangement.

[0031] The coordinate measuring machine according to the invention has at least one measuring arrangement according to the invention. Coordinate measuring machines are used for inspecting or measuring components, wherein the component is usually scanned and distances or positions are determined based on the scanning. For this purpose, an optical system and a movable frame structure and / or a high-precision positioning system are provided, which supports the component or object to be inspected. The measuring arrangement is preferably directly or indirectly connected to this movable component, i.e., frame structure or positioning system. By means of the at least one measuring arrangement, the position or distance of the movable component can be determined, whereby the scanning of the object can be controlled. Furthermore, a measuring arrangement can also be used to detect the distance or position of the component itself and thus to inspect it.The advantages and embodiments mentioned for the measuring arrangement also apply to the coordinate measuring machine comprising at least one measuring arrangement. An example of such a coordinate measuring machine (without the measuring arrangement according to the invention) is known from the publication DE10 2019 213 794A1, the entire content of which is incorporated into the present application by reference.

[0032] Further features, properties, and advantages of the present invention are described in more detail below using embodiments with reference to the accompanying figures. All features described so far and below are advantageous both individually and in any combination. The embodiments described below are merely examples and do not limit the subject matter of the invention. They show:

[0033] Figure 1 a is a schematic representation of a microlithographic projection exposure system designed for operation in the EUV,

[0034] Figure 1 b is a schematic representation of a microlithographic projection exposure system designed for operation in DUV,

[0035] Figure 2 is a schematic representation of a first embodiment of a resonator,

[0036] Figure 3 is a schematic representation of a second embodiment of a resonator,

[0037] Figure 4 is a schematic representation of a first embodiment of a measuring arrangement,

[0038] Figure 5 is a schematic representation of a second embodiment of a measuring arrangement, and

[0039] Figure 6 shows a schematic representation of a third exemplary embodiment of a measuring arrangement. Figure 1a shows a schematic representation of an exemplary projection exposure system 600 designed for operation in the EUV range, in which the present invention can be implemented. However, the invention can also be used in other nanopositioning systems.

[0040] According to Fig. 1a, an illumination device in a projection exposure system 600 designed for EUV comprises a field facet mirror 603 and a pupil facet mirror 604. The light from a light source unit, which comprises a plasma light source 601 and a collector mirror 602, is directed onto the field facet mirror 603. A first telescopic mirror 605 and a second telescopic mirror 606 are arranged in the light path downstream of the pupil facet mirror 604. A deflection mirror 607 is arranged downstream in the light path, which deflects the radiation incident upon it onto an object field in the object plane of a projection objective comprising six mirrors 651-656. At the location of the object field, a reflective structure-bearing mask 621 is arranged on a mask table 620, which is imaged by means of the projection lens into an image plane in which a substrate 661 coated with a light-sensitive layer (photoresist) is located on a wafer table 660.

[0041] The invention can also be used in a DUV system, as shown in Figure 1b. A DUV system is essentially constructed like the EUV system described above in Figure 1a, whereby mirrors and lenses can be used as optical elements in a DUV system, and the light source of a DUV system emits useful radiation in a wavelength range from 100 nm to 300 nm.

[0042] The DUV lithography system 700 shown in Figure 1b has a DUV light source 701. An ArF excimer laser, for example, can be provided as the DUV light source 701, which emits radiation 702 in the DUV range at, for example, 193 nm. A beam shaping and illumination system 703 directs the DUV radiation 702 onto a photomask 704. The photomask 704 is designed as a transmissive optical element and can be arranged outside the systems 703. The photomask 704 has a structure which is imaged in a reduced size onto a wafer 706 or the like by means of the projection system 705. The projection system 705 has a plurality of lenses 707 and / or mirrors 708 for imaging the photomask 704 onto the wafer 706. Individual lenses 707 and / or mirrors 708 of the projection system 705 can be arranged symmetrically to the optical axis 709 of the projection system 705.It should be noted that the number of lenses 707 and mirrors 708 of the DUV lithography system 700 is not limited to the number shown. More or fewer lenses 707 and / or mirrors 708 can also be provided. In particular, the beam shaping and illumination system 703 of the DUV lithography system 700 has a plurality of lenses 707 and / or mirrors 708. Furthermore, the mirrors are usually curved at their front side for beam shaping. An air gap 710 between the last lens 707 and the wafer 706 can be replaced by a liquid medium having a refractive index > 1. The liquid medium can be, for example, ultrapure water. Such a setup is also referred to as immersion lithography and has an increased photolithographic resolution.

[0043] Figure 2 shows a first schematic representation of a resonator 101 for a measuring arrangement 100 for detecting the distance or position of a movable component (not shown in detail), in particular an optical element, for example a mirror or a lens, wherein the resonator 101 has a first optical element 102, which is configured to generate a standing wave with a second optical element 103 of the resonator 101. The resonator 101 also has a reflector 104 forming the measurement target of the component, which is movably arranged in the beam path 111, 112 between the first optical element 102 and the second optical element 103 and has a first reflection surface 105 and a second reflection surface 106 arranged at an angle to the first reflection surface 105.Figure 2 shows that both reflection surfaces 105, 106 of the reflector 104 are inclined to each other and are designed to direct the incoming light beam from one of the optical elements 102, 103 to the other of the optical elements 102, 103.

[0044] At least one of the two optical elements 102, 103 is toric or has at least a toric partial surface. This enables stable coupling into the mode. Furthermore, the resonator 101 is less sensitive to tilting of the measurement target. In the present case, the first optical element 102 is formed as a toric mirror 107 or has a toric partial surface. The radius of the first optical element is preferably selected such that the beam cross-section on the first optical element 102 in both extension directions (the x and y directions) at least approximately matches, or that the deviation is less than 25%, preferably less than 20%, particularly preferably less than 10%. For a stable mode in the resonator, the radii of the toric mirror 107 should satisfy the condition Rx < 2L, L < R y< 2L where L is the length of the resonator. The first optical element 102 is therefore formed as a coupling element into the optical resonator 101 and is thus partially transmissive.

[0045] Furthermore, the reflector 104 is preferably formed as two plane mirrors spaced apart from one another and arranged at an angle to one another, with the first plane mirror having the first reflection surface 105 and the second plane mirror having the second reflection surface 106. The plane mirrors can also form a roof edge mirror. Alternatively, it is also possible for the reflector 104 to be formed as a prism, and for the reflection surfaces 105, 106 to be formed as totally reflecting surfaces of the prism.

[0046] The second optical element 103 is also formed as a mirror, which is a special case of a toric mirror, namely a cylindrical mirror 110. To make the resonator 101 even more insensitive to tilting, the cylinder radius of the second optical element 103 at least approximately corresponds to the distance between the second optical element 103 and the measurement target, with the deviation preferably being less than 20%, more preferably less than 10%, and particularly preferably less than 5%.

[0047] Alternatively or additionally, to make the resonator 101 even more insensitive to tilting of the measurement target, the second optical element 103 can be arranged concentrically or at least approximately concentrically with respect to one of its principal curvatures to a tilting point located on a tilting edge of the two reflecting surfaces 105, 106. The tilting edge of the reflecting surfaces 105, 106 is the edge at which the two reflecting surfaces 105, 106 or plane mirrors, which are aligned at an angle to one another, meet or would virtually meet, i.e., the (virtual) meeting edge of the two reflecting surfaces 105, 106. The tilting point is any point on this edge, preferably a tilting point located centrally or approximately centrally on the edge. Approximately concentric means that a deviation from the concentricity is less than 20%, preferably less than 10%, particularly preferably less than 5%.Furthermore, it is advantageous if the second optical element 103 is formed as a cylindrical mirror and is arranged such that an axis of curvature of the second optical element 103 in the y / z direction intersects the tilting edge of the reflection surfaces 105, 106. It is advantageous if the distance between the axis of curvature in the y / z direction of the second optical element 103 and the tilting edge is less than 20%, preferably less than 10%, and particularly preferably less than 5% of the radius of curvature of the second optical element 103.

[0048] Particularly at smaller measurement distances, a lateral offset of the measurement target can lead to an increasingly large lateral offset of the mode on the first optical element. Therefore, in the present case, the first partial beam path 111 arranged between the first optical element 102 and the first reflection surface 105 and the second partial beam path 112 arranged between the second reflection surface 106 and the second optical element 103 run parallel or at least approximately parallel.

[0049] In some cases, a rotation of the reflector 104 about the one virtual connecting axis between the measurement target and the first optical element 102 can nevertheless lead to an offset of the light beam on the first optical element 102. Therefore, it is advantageous if the lateral distance between the reflection surfaces 105, 106 of the reflector 104 perpendicular to this axis is as small as possible. Therefore, in some cases, it can be advantageous if—in favor of a smaller distance between the reflection surfaces 105, 106 of the reflector 104—the partial beam paths 111, 112 do not run parallel, but rather that the deviation from the parallelism of the partial beam paths 111, 112 is less than 15°, preferably less than 10°, and particularly preferably less than 5°. This is shown in Figure 3.

[0050] The resonator 101 shown in Figures 2 and 3 is designed such that one complete revolution of the light beam in the resonator 101 amounts to exactly six reflections. This reduces the number of required reflections and thus reduces the effort required for adjustment while still maintaining a comparatively high sensitivity to tilting of the measurement target. One revolution of the resonator 101 is understood to be the number of reflections necessary for the light to strike the coupling element again. In this case, the coupled-in light from the first optical element 102 strikes the first reflection surface 105 of the reflector 104. There, it is reflected for the first time and then reflected on the second reflection surface 106 of the reflector 104 onto the second optical element

[0051] 103 for the second time. From the second optical element 103, the light beam is reflected for the third time onto the second reflection surface 106 of the reflector

[0052] 104. From the second reflection surface 106, it is reflected onto the first reflection surface 105 for the fourth time. From the first reflection surface 105, the light beam is reflected back onto the first optical element 101, thus reflecting it for the fifth time. Finally, the light beam is reflected by the first optical element 102 back onto the first reflection surface 105 for the sixth time.

[0053] Figures 4 to 6 show measuring arrangements 100, wherein the measuring arrangements 100 can be designed with a parallel or approximately parallel beam path. The measuring arrangement 100 according to Figure 4 has a resonator 101 as described here. The light is guided from a light source 113, preferably via an optical fiber 114, to the resonator 101, wherein a converging lens 115 is preferably arranged in front of the coupling point of the resonator 101, i.e., in front of the first optical element 102. Due to the toric and cylindrical design of the surfaces of the resonator 101, a tilt of the components and thus of the measuring target leads to the light beam impinging on a point on the optical elements 102, 103 that is different from the non-tilted state, which in turn has a different curvature, so that it is reflected differently.The toric or cylindrical design of the optical elements 102, 103 is selected such that the reflections and the coupling into the resonator 101 are insensitive to tilting of the measurement target.

[0054] The measuring arrangement 100 shown in Figure 5 differs in that the first optical element 102 is formed as a lens 108. In this case, the lens 108 is mirrored on one side, namely the side facing the resonator 101, and has a toric partial surface 109 on this mirrored surface. Furthermore, the partial beam paths 111, 112 can run parallel or approximately parallel, with the deviation from the parallelism of the partial beam paths 111, 112 being less than 15°, preferably less than 10°, and particularly preferably less than 5°. The measuring arrangement 100 shown in Figure 6 differs in that the end of the glass fiber 116 facing the resonator 101 is mirrored. The first optical element 102 is again formed as a lens 108 with a toric partial surface 109.Furthermore, the partial beam paths 111, 112 can run parallel or approximately parallel, with the deviation from the parallelism of the partial beam paths 111, 112 being less than 15°, preferably less than 10°, and particularly preferably less than 5°. The toric partial surface 109 can also be formed (and not shown here) on the side of the lens 108 facing the glass fiber 116.

[0055] The measuring arrangement 100 according to the invention can be used in a projection exposure system 600, 700, in a lighting system, in a lithography system, in an inspection system, in a measuring machine, or in a coordinate measuring machine.

[0056] LIST OF REFERENCE SYMBOLS

[0057] 100 measuring arrangement

[0058] 101 Resonator

[0059] 102 first optical element

[0060] 103 second optical element

[0061] 104 Reflector

[0062] 105 first reflection surface

[0063] 106 second reflection surface

[0064] 107 toric mirror

[0065] 108 lens

[0066] 109 toric partial surface

[0067] 110 cylindrical mirror

[0068] 111 first partial beam path

[0069] 112 second partial beam path

[0070] 113 Light source

[0071] 114 optical fibers

[0072] 115 Converging lens

[0073] 116 mirrored end (optical fiber)

[0074] 600 projection exposure system

[0075] 601 plasma light source

[0076] 602 collector mirror

[0077] 603 field facet mirror

[0078] 604 Pupillary facet mirror

[0079] 605 first telescope mirror

[0080] 606 second telescope mirror

[0081] 607 Deflecting mirror

[0082] 620 Mask table

[0083] 621 Mask

[0084] 651 Mirror (projection lens)

[0085] 652 mirror (projection lens)

[0086] 653 Mirror (projection lens)

[0087] 654 mirror (projection lens)

[0088] 655 Mirror (projection lens) 656 Mirror (projection lens)

[0089] 660 wafer table

[0090] 661 coated substrate

[0091] 700 DUV lithography system 701 DUV light source

[0092] 702 DUV radiation / beam path

[0093] 703 Beam Forming and Illumination System (DUV)

[0094] 704 Photomask

[0095] 705 projection system 706 wafer

[0096] 707 lens

[0097] 708 mirrors

[0098] 709 optical axis

Claims

CLAIMS 1 . Measuring arrangement (100) for determining the position of a component, comprising at least one optical resonator (101) which has a first optical element (102) which is equipped with a second optical element (103) of the resonator (101) to generate a standing wave, and which has a reflector (104) forming the measurement target of the component, which is arranged to be movable in the beam path between the first optical element (102) and the second optical element (103) and has a first reflection surface (105) and a second reflection surface (106) arranged at an inclination to the first reflection surface (105), characterized in that at least one of the two optical elements (102, 103) is formed toric or has at least one toric partial surface.

2. Measuring arrangement (100) according to claim 1, characterized in that the resonator (101) is designed such that for one complete revolution through the resonator (101) the coupled-in light beam is reflected exactly six times.

3. Measuring arrangement (100) according to claim 1 or 2, characterized in that the first optical element (102) is formed as a mirror.

4. Measuring arrangement (100) according to claim 1 or 2, characterized in that the first optical element (102) is formed as a toric mirror (107) or as a mirror with a toric partial surface (109).

5. Measuring arrangement (100) according to claim 1 or 2, characterized in that the first optical element (102) is formed as a lens (108).

6. Measuring arrangement (100) according to claim 5, characterized in that the lens (108) has a toric partial surface (109) at least on one lens side.

7. Measuring arrangement (100) according to claim 5 or 6, characterized in that a surface or at least a partial surface of the lens (108) is formed mirrored.

8. Measuring arrangement (100) according to one of claims 1 to 7, characterized in that the second optical element (103) is formed as a mirror.

9. Measuring arrangement (100) according to one of claims 1 to 8, characterized in that the second optical element (103) is formed as a toric or as a cylindrical mirror (110).

10. Measuring arrangement (100) according to claim 9, characterized in that the cylinder radius of the second optical element (103) corresponds or approximately corresponds to the distance between the second optical element (103) and the measuring target, wherein the deviation is less than 20%.

11. Measuring arrangement (100) according to one of claims 1 to 10, characterized in that the first partial beam path (111) arranged between the first optical element (102) and the first reflection surface (105) and the second partial beam path (112) arranged between the second reflection surface (106) and the second optical element (103) run parallel or that the deviation from the parallelism of the partial beam paths (111, 112) is less than 15%.

12. Measuring arrangement (100) according to one of claims 1 to 11, characterized in that the reflector (104) is formed as two plane mirrors spaced apart from one another and arranged at an angle to one another, wherein the first plane mirror has the first reflection surface (105) and the second plane mirror has the second reflection surface (106).

13. Measuring arrangement (100) according to claim 12, characterized in that the plane mirrors form a roof edge mirror.

14. Measuring arrangement (100) according to one of claims 1 to 13, characterized in that the reflector (104) is formed as a prism, and that the Reflecting surfaces (105, 106) are formed as totally reflecting surfaces of the prism.

15. Measuring arrangement (100) according to one of claims 1 to 14, characterized in that the second optical element (103) is arranged concentrically or at least approximately concentrically to a tilting point lying on a tilting edge of the two reflection surfaces (105, 106).

16. Projection exposure system for a lithography system with at least one measuring arrangement (100) according to one of claims 1 to 15.

17. Illumination system for a lithography system with at least one measuring arrangement (100) according to one of claims 1 to 15.

18. Lithography system with at least one measuring arrangement (100) according to one of claims 1 to 15.

19. Inspection system with at least one measuring arrangement according to one of claims 1 to 15.

20. Measuring machine for detecting a position, geometry or shape of a component with at least one measuring arrangement according to one of claims 1 to 15.

21. Coordinate measuring machine with at least one measuring arrangement according to one of claims 1 to 15.

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