OPTICAL SYSTEM, LITHOGRAPHING PLANT AND METHOD FOR MANUFACTURING AN OPTICAL SYSTEM

Abstract

Optical system (100) for a lithography system (1), comprising a component (102) and a damping device (104) for damping mechanical vibrations of the component (102), wherein the damping device (104) comprises: a damper mass (106) which is attached to the component (102) by means of an elastic element (108), a magnetorheological fluid (112) and / or a magnetorheological elastomer, wherein the absorber mass (106) comprises the magnetorheological elastomer and / or is surrounded by the magnetorheological fluid (112), and a magnetic device (114) which is designed to apply a magnetic force (F B ) to achieve an absorber frequency (f T ) of the damper device (104).

Description

[0001] The present invention relates to an optical system, a lithography system with such an optical system and a method for producing such an optical system.

[0002] Microlithography is used to manufacture microstructured components, such as integrated circuits. The microlithography process is carried out using a lithography system equipped with an illumination system and a projection system. The image of a mask (reticle) illuminated by the illumination system is projected by the projection system onto a substrate, such as a silicon wafer, coated with a light-sensitive layer (photoresist) and arranged in the image plane of the projection system in order to transfer the mask structure to the light-sensitive coating of the substrate.

[0003] Driven by the pursuit of ever smaller structures in the production of integrated circuits, EUV lithography systems are currently being developed that use light with a wavelength in the range of 0.1 nm to 30 nm, particularly 13.5 nm. Since most materials absorb light at this wavelength, such EUV lithography systems must use reflective optics, i.e., mirrors, instead of the previously used refractive optics, i.e., lenses.

[0004] During operation of such a lithography system, it is unavoidable that mechanical vibrations are coupled into the optical and mechanical components of the lithography system. These mechanical vibrations can be caused, for example, by floor vibrations or transmitted by other components, e.g., a movable wafer holder, a movable reticle holder, or other components of the lithography system. Furthermore, the passage of cooling water through components of the lithography system can also lead to vibration excitation. To dampen such mechanical vibrations, it is known to insert damping elements between moving masses and / or to use damping devices, such as those proposed in DE 10 2023 201 560 A1.

[0005] Against this background, it is an object of the present invention to provide an improved optical system.

[0006] Accordingly, an optical system for a lithography system is proposed. The optical system comprises a component and a damping device for damping mechanical vibrations of the component. The damping device also comprises: a damper mass which is attached to the component by means of an elastic element, a magnetorheological fluid and / or a magnetorheological elastomer, wherein the absorber mass comprises the magnetorheological elastomer and / or is surrounded by the magnetorheological fluid, and a magnetic device which is configured to apply a magnetic force to the magnetorheological fluid and / or the magnetorheological elastomer in order to adjust an absorber frequency of the absorber device.

[0007] This allows the damping frequency of the damping device to be precisely adjusted. For example, the initial damping frequency of the damping device is specified by the design of the damping mass and the elastic element. Furthermore, the initial damping frequency can be finely adjusted after the damping mass and the elastic element have been provided and / or manufactured using the magnetic device and the magnetorheological fluid / elastomer.

[0008] For example, a natural frequency of the component can first be recorded (e.g., measured). For example, a frequency of a main vibration mode of the component can be recorded. In a case where the initial damper frequency deviates from the recorded natural frequency of the component, the proposed damper device can be used to adjust the damper frequency of the damper device based on the initial damper frequency according to the recorded natural frequency of the component.

[0009] The damping device allows for damping control by changing the effect of the magnetic device on the magnetorheological damping component (i.e., the magnetorheological fluid and / or the magnetorheological elastomer). By changing the damping, vibration damping can be optimized, adapted to the specific operating conditions of the optical system, particularly to the component's natural vibrations.

[0010] For example only, the magnetic device and the magnetorheological fluid / elastomer are configured to increase and / or decrease an initial damping frequency of the damping device by up to 10%, up to 20%, and / or up to 30%. However, the magnetic device and the magnetorheological fluid / elastomer can also be configured to increase and / or decrease the damping frequency of the damping device by a different percentage based on the initial damping frequency.

[0011] The lithography system (projection exposure system) is, for example, an EUV or DUV lithography system. EUV stands for "extreme ultraviolet" (EUV) and refers to a wavelength of the working light in the range of 0.1 nm to 30 nm, specifically 13.5 nm. Furthermore, DUV stands for "deep ultraviolet" (DUV) and refers to a wavelength of the working light between 30 nm and 250 nm.

[0012] The EUV or DUV lithography system comprises an illumination system and a projection system. In particular, the EUV or DUV lithography system projects the image of a mask (reticle) illuminated by the illumination system onto a substrate coated with a light-sensitive layer (photoresist) and arranged in the image plane of the projection system, for example, a silicon wafer, using the projection system to transfer the mask structure to the light-sensitive coating of the substrate.

[0013] The optical system is preferably a projection optics system of the lithography system. However, the optical system can also be an illumination system of the lithography system.

[0014] The component is, in particular, an optical or mechanical component of the lithography system. An optical component is, for example, a mirror or a lens of the lithography system. A mechanical component is, for example, a support element, a support frame, a support plate, a holder, a connecting element that connects two components, and / or a bearing.

[0015] The damper mass can be cylindrical. Alternatively, the damper mass can also be plate-shaped. In particular, the damper mass can have a cuboid or cube-shaped geometry. In principle, however, the damper mass can have any desired geometry. The damper mass can have a size and / or length (e.g., cylinder length, edge length) of a few millimeters or even a fraction of a millimeter.

[0016] The damper mass is attached to the component and thus coupled to it. The damper mass is operatively connected to the component, particularly by means of the elastic element. The damper mass can be deflected from a rest position and oscillate. For example, the damper mass (or the damper mass together with the elastic element) has at least approximately the same natural frequency as the component. This allows the amplitude of a mechanical vibration of the component to be damped by an antiphase oscillation of the damper mass.

[0017] The elastic element comprises, for example, a spring, a leaf spring and / or a flexure joint.

[0018] The damper mass and the elastic element together form a tuned mass damper (TMD), e.g., a micro-damper, mounted on the component. By additionally providing the magnetic device and the magnetorheological fluid / elastomer, the component's oscillating behavior due to any excitation can be damped over as broad a range as possible. In particular, the damper frequency of the damper device can be optimized to ensure optimal damping of mechanical vibrations introduced into the component.

[0019] The component may comprise any number of such damping devices.

[0020] The magnetorheological fluid is, in particular, a liquid and / or a dispersion whose viscosity can be changed under the influence of an external magnetic field. This allows the viscosity of the magnetorheological fluid to be specifically adjusted. This effect is created by particles of magnetic material homogeneously distributed in a carrier fluid, which align in a chain-like manner in the direction of the magnetic field lines under the influence of a magnetic field. Shear forces acting perpendicular to the magnetic field lines are thereby intensified (e.g., by several orders of magnitude). The intensification of the shear forces corresponds to an increase in the viscosity of the magnetorheological fluid. With regard to the composition of the fluid, this effect depends primarily on the core particle size of the magnetic particles.

[0021] A magnetorheological elastomer, for example, comprises an elastomer matrix and magnetically active particles dispersed within the elastomer matrix. The main component of a magnetorheological elastomer is an elastic polymer, such as EPDM (ethylene propylene diene elastomer) and / or FKM (fluororubber), into which magnetically active particles (e.g., iron particles) are introduced and specifically aligned in a flowable state. After the polymer cures, the elastomer with magnetorheological properties is formed.

[0022] In a magnetorheological elastomer, its viscoelastic and / or dynamic-mechanical properties can be modified (e.g., quickly and reversibly) by applying an external magnetic field. In particular, the spring rate of the magnetorheological elastomer can be controlled by influencing the magnetic field strength. The magnetorheological effect of a magnetorheological elastomer is based on a dipole-dipole interaction (similar to magnetorheological fluids) and / or on a distortion of the magnetic field in the immediate vicinity of each particle and the resulting magnetic inhomogeneity forces.

[0023] The damper mass comprising the magnetorheological elastomer includes, for example, the case where the damper mass is made of the magnetorheological elastomer. For example, the elastic element by which the damper mass is attached to the component can also comprise a / the magnetorheological elastomer. In this case, the elastic element and the damper mass can also be integral, in particular made of a single piece of material.

[0024] The fact that the absorber mass is surrounded by the magnetorheological fluid means, for example, that the absorber mass itself does not contain any magnetorheological material (i.e., it is free of any magnetorheological material).

[0025] The magnetic device is arranged, for example, adjacent to the magnetorheological fluid and / or the magnetorheological elastomer. By way of example only, the magnetic device is arranged such that it surrounds the magnetorheological fluid / elastomer, or the magnetorheological elastomer is arranged such that it surrounds the magnetic device.

[0026] The magnetic device is in particular designed to generate a magnetic field at the location of the magnetorheological fluid and / or the magnetorheological elastomer. The magnetic device is in particular designed to generate a predetermined magnetic field strength at the location of the magnetorheological fluid and / or the magnetorheological elastomer.

[0027] The wiping frequency of the wiping device is in particular a natural frequency of the wiping device.

[0028] According to an embodiment, the wiping device comprises: a container attached to the component, in which the absorber mass and the magnetorheological fluid are accommodated, so that the absorber mass is surrounded by the magnetorheological fluid, wherein the magnetic device is arranged adjacent to the container and is configured to apply the magnetic force to the magnetorheological fluid in order to adjust a viscosity of the magnetorheological fluid.

[0029] By applying a magnetic force to the magnetorheological fluid, the viscosity of the magnetorheological fluid is changed. Consequently, by applying a predetermined magnetic force to the magnetorheological fluid, the viscosity of the magnetorheological fluid can be adjusted. Since the damper mass is surrounded by the magnetorheological fluid and thus moves (e.g., oscillates) within the magnetorheological fluid, the damper frequency of the damper device is adjusted by adjusting the viscosity of the magnetorheological fluid.

[0030] The container is, in particular, a fluid container. The container is, in particular, a closed container. The container is, in particular, a fluid-tight container, e.g., a liquid-tight container.

[0031] For example, the grinding mass and the magnetorheological fluid are received in the container such that the grinding mass is completely surrounded by the magnetorheological fluid.

[0032] According to a further embodiment, the grinding mass is rotationally symmetric about a symmetry axis of the grinding mass, the container is rotationally symmetric about the symmetry axis, and / or the magnetic device is rotationally symmetric about the symmetry axis.

[0033] For example, an electromagnetic device of the grinding device can be arranged annularly around a circumference of the container.

[0034] According to a further embodiment, the magnetic device is an electromagnetic device.

[0035] This allows the magnetic field strength to be adjusted by changing the current flow in a coil of the electromagnet device. This allows the magnetic force applied to the magnetorheological fluid / elastomer to be easily adjusted. For example, a predetermined magnetic field strength can be easily provided at the location of the magnetorheological fluid / elastomer.

[0036] In other embodiments, however, the magnetic device may also comprise one or more permanent magnets. For example, the one or more permanent magnets and / or their number are selected such that a predetermined magnetic force acts on the magnetorheological fluid / elastomer or a predetermined magnetic field strength is provided at the location of the magnetorheological fluid / elastomer.

[0037] According to a further aspect, a lithography system with an optical system as described above is proposed.

[0038] According to a further aspect, a method for producing an optical system for a lithography system as described above is proposed. The method comprises the steps: a) Providing a component of the optical system, b) Determining a natural frequency of the component, c) Adjusting an absorber frequency of the absorber device as a function of the detected natural frequency of the component, wherein the absorber frequency is adjusted by adjusting the magnetic force of the magnetic device with which the magnetorheological fluid and / or the magnetorheological elastomer is acted upon.

[0039] For example, in step b), the component is excited to vibrate (e.g., using one or more actuators and / or a shaking device). Furthermore, the component's natural frequency is recorded, e.g., using sensors attached to the component.

[0040] Furthermore, the method may comprise, between steps b) and c), determining a deviation of the detected natural frequency of the component from an initial damper frequency of the damper device. The initial damper frequency of the damper device is determined, for example, by the design of the damper mass and the elastic element. Then, in step c), the damper frequency of the damper device can be adjusted depending on the determined deviation.

[0041] The described method, in particular steps b) and c), can also be carried out for operating an optical system as described above. For example, steps b) and c) can also be carried out repeatedly.

[0042] In this case, "one" is not necessarily limited to exactly one element. Rather, multiple elements, such as two, three, or more, may also be included. Any other counting term used here should also not be understood as implying a limitation to the exact number of elements stated. Rather, numerical deviations, both upward and downward, are possible unless otherwise stated.

[0043] The embodiments and features described for the optical system apply accordingly to the proposed method and vice versa.

[0044] Further possible implementations of the invention also include combinations of features or embodiments described above or below with respect to the exemplary embodiments that are not explicitly mentioned. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0045] Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the exemplary embodiments of the invention described below. The invention will be explained in more detail below using preferred embodiments with reference to the accompanying figures. Fig. 1 shows a schematic meridional section of a projection exposure apparatus for EUV projection lithography according to an embodiment; Fig. 2 shows an optical system of EUV projection lithography from Fig. 1 according to an embodiment, wherein the optical system comprises a component and a damping device for damping mechanical vibrations of the component; and Fig. 3 shows a flow diagram of a method for manufacturing an optical system according to an embodiment.

[0046] In the figures, identical or functionally equivalent elements are provided with the same reference numerals unless otherwise stated. Furthermore, it should be noted that the representations in the figures are not necessarily to scale.

[0047] Fig. 1 shows an embodiment of a projection exposure system 1 (lithography system), in particular an EUV lithography system. One embodiment of an illumination system 2 of the projection exposure system 1 has, in addition to a light or radiation source 3, an illumination optics 4 for illuminating an object field 5 in an object plane 6. In an alternative embodiment, the light source 3 can also be provided as a separate module from the remaining illumination system 2. In this case, the illumination system 2 does not include the light source 3.

[0048] A reticle 7 arranged in the object field 5 is exposed. The reticle 7 is held by a reticle holder 8. The reticle holder 8 can be displaced via a reticle displacement drive 9, in particular in a scanning direction.

[0049] In the Fig. For illustrative purposes, Figure 1 shows a Cartesian coordinate system with an x-direction x, a y-direction y, and a z-direction z. The x-direction x runs perpendicular to the plane of the drawing. The y-direction y runs horizontally, and the z-direction z runs vertically. The scanning direction runs in the Fig. 1 along the y-direction y. The z-direction z runs perpendicular to the object plane 6.

[0050] The projection exposure system 1 comprises a projection optics 10. The projection optics 10 serves to image the object field 5 into an image field 11 in an image plane 12. The image plane 12 runs parallel to the object plane 6. Alternatively, an angle other than 0° between the object plane 6 and the image plane 12 is also possible.

[0051] A structure on the reticle 7 is imaged onto a light-sensitive layer of a wafer 13 arranged in the image plane 12 in the region of the image field 11. The wafer 13 is held by a wafer holder 14. The wafer holder 14 can be displaced, in particular along the y-direction y, via a wafer displacement drive 15. The displacement of the reticle 7, on the one hand, via the reticle displacement drive 9, and the displacement of the wafer 13, on the other hand, via the wafer displacement drive 15, can be synchronized with each other.

[0052] The light source 3 is an EUV radiation source. The light source 3 emits, in particular, EUV radiation 16, which is also referred to below as useful radiation, illumination radiation, or illumination light. The useful radiation 16 has, in particular, a wavelength in the range between 5 nm and 30 nm. The light source 3 can be a plasma source, for example an LPP source (Laser Produced Plasma) or a DPP source (Gas Discharged Produced Plasma). It can also be a synchrotron-based radiation source. The light source 3 can be a free-electron laser (FEL).

[0053] The illumination radiation 16 emanating from the light source 3 is focused by a collector 17. The collector 17 can be a collector with one or more ellipsoidal and / or hyperboloidal reflection surfaces. The at least one reflection surface of the collector 17 can be exposed to the illumination radiation 16 at grazing incidence (GI), i.e., at angles of incidence greater than 45°, or at normal incidence (NI), i.e., at angles of incidence less than 45°. The collector 17 can be structured and / or coated, on the one hand, to optimize its reflectivity for the useful radiation and, on the other hand, to suppress stray light.

[0054] After the collector 17, the illumination radiation 16 propagates through an intermediate focus in an intermediate focal plane 18. The intermediate focal plane 18 can represent a separation between a radiation source module, comprising the light source 3 and the collector 17, and the illumination optics 4.

[0055] The illumination optics 4 comprises a deflecting mirror 19 and, downstream of this in the beam path, a first facet mirror 20. The deflecting mirror 19 can be a flat deflecting mirror or, alternatively, a mirror with a beam-influencing effect beyond the pure deflection effect. Alternatively or additionally, the deflecting mirror 19 can be designed as a spectral filter that separates a useful light wavelength of the illumination radiation 16 from stray light of a different wavelength. If the first facet mirror 20 is arranged in a plane of the illumination optics 4 that is optically conjugated to the object plane 6 as the field plane, it is also referred to as a field facet mirror. The first facet mirror 20 comprises a plurality of individual first facets 21, which can also be referred to as field facets. Of these first facets 21, Fig. 1 only some examples are shown.

[0056] The first facets 21 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or partially circular edge contour. The first facets 21 can be designed as flat facets or, alternatively, as convexly or concavely curved facets.

[0057] As is known, for example, from DE 10 2008 009 600 A1, the first facets 21 themselves can also be composed of a plurality of individual mirrors, in particular a plurality of micromirrors. The first facet mirror 20 can, in particular, be designed as a microelectromechanical system (MEMS system). For details, reference is made to DE 10 2008 009 600 A1.

[0058] Between the collector 17 and the deflecting mirror 19, the illumination radiation 16 runs horizontally, i.e. along the y-direction y.

[0059] In the beam path of the illumination optics 4, a second facet mirror 22 is arranged downstream of the first facet mirror 20. If the second facet mirror 22 is arranged in a pupil plane of the illumination optics 4, it is also referred to as a pupil facet mirror. The second facet mirror 22 can also be arranged at a distance from a pupil plane of the illumination optics 4. In this case, the combination of the first facet mirror 20 and the second facet mirror 22 is also referred to as a specular reflector.

[0060] Specular reflectors are known from US 2006 / 0132747 A1, EP 1 614 008 B1 and US 6,573,978.

[0061] The second facet mirror 22 comprises a plurality of second facets 23. In the case of a pupil facet mirror, the second facets 23 are also referred to as pupil facets.

[0062] The second facets 23 can also be macroscopic facets, which can, for example, be round, rectangular, or hexagonal, or alternatively facets composed of micromirrors. Reference is also made to DE 10 2008 009 600 A1 in this regard.

[0063] The second facets 23 may have planar or alternatively convex or concave curved reflection surfaces.

[0064] The illumination optics 4 thus form a double-faceted system. This basic principle is also known as a fly's-eye integrator.

[0065] It may be advantageous not to arrange the second facet mirror 22 exactly in a plane that is optically conjugate to a pupil plane of the projection optics 10. In particular, the second facet mirror 22 can be arranged tilted relative to a pupil plane of the projection optics 10, as described, for example, in DE 10 2017 220 586 A1.

[0066] With the help of the second facet mirror 22, the individual first facets 21 are imaged into the object field 5. The second facet mirror 22 is the last bundle-forming mirror or actually the last mirror for the illumination radiation 16 in the beam path before the object field 5.

[0067] In a further embodiment of the illumination optics 4 (not shown), a transmission optics can be arranged in the beam path between the second facet mirror 22 and the object field 5, which transmission optics contributes in particular to the imaging of the first facets 21 into the object field 5. The transmission optics can have exactly one mirror, but alternatively also two or more mirrors, which are arranged one behind the other in the beam path of the illumination optics 4. The transmission optics can in particular comprise one or two mirrors for normal incidence (NI mirrors, normal incidence mirrors) and / or one or two mirrors for grazing incidence (GI mirrors, grazing incidence mirrors).

[0068] The illumination optics 4 has in the version shown in the Fig. 1, after the collector 17 there are exactly three mirrors, namely the deflection mirror 19, the first facet mirror 20 and the second facet mirror 22.

[0069] In a further embodiment of the illumination optics 4, the deflection mirror 19 can also be omitted, so that the illumination optics 4 can then have exactly two mirrors after the collector 17, namely the first facet mirror 20 and the second facet mirror 22.

[0070] The imaging of the first facets 21 by means of the second facets 23 or with the second facets 23 and a transmission optics into the object plane 6 is usually only an approximate imaging.

[0071] The projection optics 10 comprises a plurality of mirrors Mi, which are numbered according to their arrangement in the beam path of the projection exposure system 1.

[0072] In the Fig. In the example shown in Figure 1, the projection optics 10 comprises six mirrors M1 to M6. Alternatives with four, eight, ten, twelve, or a different number of mirrors M1 are also possible. The projection optics 10 is a doubly obscured optic. The penultimate mirror M5 and the last mirror M6 each have a passage opening for the illumination radiation 16. The projection optics 10 has an image-side numerical aperture that is greater than 0.5 and can also be greater than 0.6, for example, 0.7 or 0.75.

[0073] Reflection surfaces of the mirrors Mi can be designed as freeform surfaces without a rotational symmetry axis. Alternatively, the reflection surfaces of the mirrors Mi can be designed as aspherical surfaces with exactly one rotational symmetry axis of the reflection surface shape. The mirrors Mi, like the mirrors of the illumination optics 4, can have highly reflective coatings for the illumination radiation 16. These coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.

[0074] The projection optics 10 has a large object-image offset in the y-direction y between a y-coordinate of a center of the object field 5 and a y-coordinate of the center of the image field 11. This object-image offset in the y-direction y can be approximately as large as a z-distance between the object plane 6 and the image plane 12.

[0075] The projection optics 10 can, in particular, be anamorphic. It has, in particular, different magnifications βx, βy in the x and y directions x, y. The two magnifications βx, βy of the projection optics 10 are preferably (βx, βy) = (+ / - 0.25, + / - 0.125). A positive magnification β means imaging without image inversion. A negative sign for the magnification B means imaging with image inversion.

[0076] The projection optics 10 thus leads to a reduction in the ratio 4:1 in the x-direction x, i.e. in the direction perpendicular to the scanning direction.

[0077] The projection optics 10 leads to a reduction of 8:1 in the y-direction y, i.e. in the scanning direction.

[0078] Other magnifications are also possible. Magnifications with the same sign and absolutely identical in the x and y directions (x, y), for example, with absolute values ​​of 0.125 or 0.25, are also possible.

[0079] The number of intermediate image planes in the x- and y-directions x, y in the beam path between the object field 5 and the image field 11 can be the same or can be different depending on the design of the projection optics 10. Examples of projection optics with different numbers of such intermediate images in the x- and y-directions x, y are known from US 2018 / 0074303 A1.

[0080] Each of the second facets 23 is assigned to exactly one of the first facets 21 to form a respective illumination channel for illuminating the object field 5. This can, in particular, result in illumination according to the Köhler principle. The far field is divided into a plurality of object fields 5 using the first facets 21. The first facets 21 generate a plurality of images of the intermediate focus on the second facets 23 assigned to them.

[0081] The first facets 21 are each imaged onto the reticle 7 by an associated second facet 23, superimposed on one another, to illuminate the object field 5. The illumination of the object field 5 is, in particular, as homogeneous as possible. It preferably has a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.

[0082] By arranging the second facets 23, the illumination of the entrance pupil of the projection optics 10 can be geometrically defined. By selecting the illumination channels, in particular the subset of the second facets 23 that guide light, the intensity distribution in the entrance pupil of the projection optics 10 can be adjusted. This intensity distribution is also referred to as the illumination setting or illumination pupil fill.

[0083] A likewise preferred pupil uniformity in the area of ​​defined illuminated sections of an illumination pupil of the illumination optics 4 can be achieved by redistributing the illumination channels.

[0084] Further aspects and details of the illumination of the object field 5 and in particular of the entrance pupil of the projection optics 10 are described below.

[0085] The projection optics 10 can, in particular, have a homocentric entrance pupil. This can be accessible. It can also be inaccessible.

[0086] The entrance pupil of the projection optics 10 cannot usually be precisely illuminated with the second facet mirror 22. When the projection optics 10 images the center of the second facet mirror 22 telecentrically onto the wafer 13, the aperture rays often do not intersect at a single point. However, a surface can be found in which the pairwise determined distance of the aperture rays is minimized. This surface represents the entrance pupil or a surface conjugate to it in spatial space. In particular, this surface exhibits a finite curvature.

[0087] It is possible that the projection optics 10 have different entrance pupil positions for the tangential and sagittal beam paths. In this case, an imaging element, in particular an optical component of the transmission optics, should be provided between the second facet mirror 22 and the reticle 7. With the help of this optical element, the different positions of the tangential entrance pupil and the sagittal entrance pupil can be taken into account.

[0088] At the Fig. In the arrangement of the components of the illumination optics 4 shown in Figure 1, the second facet mirror 22 is arranged in a surface conjugate to the entrance pupil of the projection optics 10. The first facet mirror 20 is arranged tilted relative to the object plane 6. The first facet mirror 20 is arranged tilted relative to an arrangement plane defined by the deflection mirror 19. The first facet mirror 20 is arranged tilted relative to an arrangement plane defined by the second facet mirror 22.

[0089] Fig. 2 shows an optical system 100 of the EUV projection lithography 1 from Fig. 1 according to one embodiment.

[0090] The optical system 100 has a component 102 and a damping device 104 for damping mechanical vibrations of the component 102.

[0091] The damping device 104 comprises a damping mass 106, which is attached to the component 102 by means of an elastic element 108. The damping mass 106 is, for example, rotationally symmetrical to an axis of symmetry A of the damping mass 106. The damping mass 106 is, for example, cylindrical. However, the damping mass 106 can also have a different geometric shape.

[0092] The damper device 104 also includes a container 110 attached to the component 102. A magnetorheological fluid 112 is contained in the container 110. Furthermore, the container 110 surrounds the damper mass 106, so that the damper mass 106 is (e.g., completely) surrounded by the magnetorheological fluid 112.

[0093] As an example, the container 110 is arranged and designed to be rotationally symmetric about the axis of symmetry A of the grinding mass 106. For example, the container 110 is also cylindrical. For example, the container 110 is arranged concentrically with the grinding mass 106. However, the container 110 can also have another geometric shape.

[0094] Furthermore, a magnetic device 114, e.g. an electromagnetic device 116, is provided. The magnetic device 114 is arranged in particular adjacent to the container 110, for example directly adjoining it or spaced therefrom. The magnetic device 114 is configured to generate a magnetic field and to apply a magnetic force F to the magnetorheological fluid 112. B to act on it. By the magnetic force F Ba viscosity of the magnetorheological fluid 112 is changed. By changing the viscosity of the magnetorheological fluid 112 in which the damping mass 106 moves, a damper frequency f T the damper device 104 can be adjusted.

[0095] For example only, the magnetic device 114 is designed and arranged rotationally symmetrically to the axis of symmetry A of the damper mass 106. For example, the magnetic device 114 has a cylindrical shape. The magnetic device 114 can, for example, be arranged concentrically to the damper mass 106 and / or to the container 110. However, in other examples, the magnetic device 114 can also have a different shape.

[0096] The optical system 100 can also be used, for example, in a DUV lithography system.

[0097] In the following, with reference to Fig.3 describes a method for producing an optical system 100 for a lithography system 1.

[0098] In a first step S1 of the method, a component 102 of the optical system 100 is provided.

[0099] In a second step S2 of the method, a natural frequency f E of the component 102 is recorded (e.g. measured).

[0100] In a third step S3 of the method, an absorber frequency f T of the damper device 104 by adjusting the magnetic force F B the magnetic device 114, with which the magnetorheological fluid 112 is acted upon.

[0101] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. LIST OF REFERENCE SYMBOLS 1 projection exposure system 2 Lighting system 3 Light source 4 Lighting optics 5 Object field 6 Object level 7 reticles 8 reticle holders 9 Reticle displacement drive 10 Projection optics 11 Image field 12 Image plane 13 wafers 14 wafer holders 15 Wafer relocation drive 16 Illumination radiation 17 Collector 18 Intermediate focal plane 19 Deflecting mirrors 20 first facet mirror 21 first facet 22 second facet mirror 23 second facet 100 optical system 102 component 104 Damping device 106 absorber mass 108 elements 110 containers 112 Fluid 114 Magnetic device 116 Electromagnetic device A axis f E frequency f T frequency F B Power M1-M6 mirrors S1-S3 process steps QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2023 201 560 A1

[0004] DE 10 2008 009 600 A1 [0057, 0062] US 2006 / 0132747 A1

[0060] EP 1 614 008 B1

[0060] US 6,573,978

[0060] DE 10 2017 220 586 A1

[0065] US 2018 / 0074303 A1

[0079]

Claims

[1] Optical system (100) for a lithography system (1), comprising a component (102) and a damping device (104) for damping mechanical vibrations of the component (102), wherein the damping device (104) comprises: a damper mass (106) which is attached to the component (102) by means of an elastic element (108), a magnetorheological fluid (112) and / or a magnetorheological elastomer, wherein the absorber mass (106) comprises the magnetorheological elastomer and / or is surrounded by the magnetorheological fluid (112), and a magnetic device (114) which is designed to apply a magnetic force (F B ) to achieve an absorber frequency (f T ) of the damper device (104). [2] Optical system according to claim 1, wherein the damper device (104) has a container (110) attached to the component (102), in which the damper mass (106) and the magnetorheological fluid (112) are accommodated, so that the damper mass (106) is surrounded by the magnetorheological fluid (112), and the magnetic device (114) is arranged adjacent to the container (110) and is designed to actuate the magnetorheological fluid (112) with the magnetic force (F B ) in order to adjust a viscosity of the magnetorheological fluid (112). [3] Optical system according to claim 2, wherein the absorber mass (106) is rotationally symmetrical to an axis of symmetry (A) of the absorber mass (106), the container (110) is rotationally symmetrical to the axis of symmetry (A), and / or the magnetic device (110) is rotationally symmetrical to the axis of symmetry (A). [4] An optical system according to any one of claims 1 to 3, wherein the magnetic means (114) is an electromagnet means (116). [5] Lithography system (1) with an optical system (100) according to one of claims 1 to 4. [6] Method for producing an optical system (100) according to one of claims 1 to 4 for a lithography system (1), comprising the steps: a) providing (S1) a component (102) of the optical system (100), b) Detecting (S2) a natural frequency (f E ) of the component (102), c) Setting (S3) an absorber frequency (f T ) of the damper device (104) as a function of the detected natural frequency (f E ) of the component (102), wherein the absorber frequency (f T ) by adjusting the magnetic force (F B ) of the magnetic device (114) with which the magnetorheological fluid (112) and / or the magnetorheological elastomer is acted upon.

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