OPTICAL SYSTEM, PROJECTION ILLUMINATION SYSTEM AND METHOD

Abstract

An optical system (100) for a projection exposure system (1), comprising an optical element (102, 102'), and a weight force compensator (200A) for compensating a weight force (G) of the optical element (102, 102'), wherein the weight force compensator (200A) has a passive magnetic circuit (228) for generating a compensating force (K) opposing the weight force (G), wherein the weight force compensator (200A) has an adjusting element (236, 236', 238, 238') for adjusting the compensating force (K), and wherein the adjusting element (236, 236', 238, 238') is clamped on the outside of an outer shell (208) of the weight force compensator (200A).

Description

[0001] The present invention relates to an optical system for a projection exposure system, a projection exposure system with such an optical system and a method for adjusting a compensation force of a weight force compensator of 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, which includes an illumination system and a projection system. The image of a mask (reticule) illuminated by the illumination system is projected by the projection system onto a substrate, such as a silicon wafer, coated with a photosensitive layer (photoresist) and positioned in the image plane of the projection system. This transfers the mask structure onto the photosensitive coating of the substrate.

[0003] Driven by the pursuit of ever smaller structures in the fabrication of integrated circuits, EUV lithography systems are currently being developed that utilize light with wavelengths ranging from 0.1 nm to 30 nm, particularly 13.5 nm. Due to the high absorption of light of this wavelength by most materials, such EUV lithography systems require reflective optics, i.e., mirrors, instead of the previously used refracting optics, i.e., lenses.

[0004] Actuators are used to adjust such mirrors, deflecting the mirror in the process. To minimize unwanted heat generation from the actuators, the mirror's weight can be absorbed by a compensator. A compensating force generated by such a compensator, acting against the mirror's weight, can be produced by a passive magnetic circuit. This compensating force can be influenced by a movable soft magnetic ring attached to the outside of the compensator.

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

[0006] Accordingly, an optical system for a projection exposure system is proposed. The optical system comprises an optical element and a weight compensator for compensating a weight force of the optical element, wherein the weight compensator has a passive magnetic circuit for generating a compensating force opposing the weight force, wherein the weight compensator has an adjusting element for adjusting the compensating force, and wherein the adjusting element is clamped externally onto an outer shell of the weight compensator.

[0007] Because the adjusting element is clamped to the outer shell of the weight-force compensator, a complex adjustment mechanism for changing its position is unnecessary. Furthermore, clamping the adjusting element to the outer shell eliminates the need for an additional connection between the adjusting element and the outer shell. This allows for a simpler design and therefore a more cost-effective manufacturing process for the weight-force compensator.

[0008] The optical system can be a projection optic or part of a projection optic. Therefore, the optical system can also be referred to as a projection optic. However, the optical system can also be an illumination system or part of an illumination system. Therefore, the optical system can also be referred to as an illumination system. The optical system is suitable for EUV lithography. However, the optical system can also be suitable for DUV lithography.

[0009] The optical system can comprise several optical elements. However, only one optical element is referred to below. The optical element can be, for example, a mirror, in particular an EUV mirror. The optical element can comprise a substrate and an optically effective surface provided on the substrate, for example, a mirror surface. The optically effective surface is suitable for reflecting light, in particular EUV radiation. The optically effective surface can be realized by a coating.

[0010] The optical element has, in particular, six degrees of freedom: three translational degrees of freedom along a first spatial direction (x-direction), a second spatial direction (y-direction), and a third spatial direction (z-direction), and three rotational degrees of freedom around the x-direction, the y-direction, and the z-direction. This means that the position and orientation of the optical element can be determined or described using these six degrees of freedom.

[0011] The "position" of the optical element refers in particular to its coordinates or the coordinates of a measuring point provided on the optical element with respect to the x-direction, the y-direction, and the z-direction. The "orientation" of the optical element refers in particular to its tilt with respect to the three spatial directions. That is, the optical element can be tilted about the x-direction, the y-direction, and / or the z-direction.

[0012] This results in six degrees of freedom for the position and orientation of the optical element. A "position" of the optical element encompasses both its position and its orientation. The term "position" can therefore be replaced by the phrase "position and orientation," and vice versa. The optical element can, for example, be moved from an actual position to a desired position and vice versa. For instance, the optical element in the desired position fulfills certain optical specifications or requirements that the optical element in the actual position does not.

[0013] To move the optical element from its current position to the desired position, the optical system includes an actuator assembly. The actuator assembly allows the optical element to be adjusted or its position changed. In particular, the actuator assembly can be part of an adjustment device. The adjustment device can have multiple actuator assemblies. For example, the adjustment device has three actuator assemblies, which allow the optical element to be adjusted in its six degrees of freedom. Each actuator assembly can include multiple actuators, for example, two. Furthermore, each actuator assembly has a weight compensator, as mentioned previously. However, this is not mandatory. In other words, a weight compensator does not necessarily have to be located on every actuator assembly. It is also possible to have exactly one weight compensator, functioning as a central, independent unit.Furthermore, it is also possible that only two actuator arrangements each have a weight force compensator.

[0014] The actuator arrangement is designed to adjust the optical element. In this context, "adjusting" or "aligning" the optical element refers specifically to changing its position. For example, the optical element can be moved from its current position to the desired position and vice versa using the actuator arrangement. The adjustment or alignment of the optical element can be performed in all six degrees of freedom mentioned above.

[0015] The fact that the weight force compensator is suitable to "compensate" for the weight force of the optical element means in particular that the weight force compensator is designed to generate a force, especially the aforementioned compensation force, which acts against the weight force of the optical element, so that the actuator arrangement does not have to work against the weight force of the optical element when adjusting it.

[0016] A weight force compensator preferably has a symmetry or central axis, about which the weight force compensator can be rotationally symmetrical. Furthermore, the weight force compensator can have a radial direction that is perpendicular to and oriented away from the central axis.

[0017] In addition to the outer shell, the weight force compensator preferably comprises a tubular inner element arranged within the outer shell. The inner element is suspended from the outer shell, in particular by means of a first leaf spring element and a second leaf spring element. This allows the inner element to move axially along its central axis relative to the outer shell. However, the leaf spring elements prevent radial movement of the inner element relative to the outer shell as well as tilting of the inner element.

[0018] The passive magnetic circuit is arranged, in particular, between the outer shell and the inner element. The passive magnetic circuit preferably comprises an outer magnetic ring, which is attached to the inside of the outer shell. Furthermore, the passive magnetic circuit comprises a first inner magnetic ring and a second inner magnetic ring, both of which are attached to the inner element. The inner magnetic rings are spaced apart from each other along the central axis. The magnetic rings are permanent magnets.

[0019] The passive magnetic circuit generates a force acting on the inner element. This causes the inner element to either "float" within the outer shell or be deflected to such an extent that a compensating force opposing the force of gravity is generated. Using the adjusting element, which can be made of a soft magnetic material, for example, the magnetic field generated by the passive magnetic circuit can be influenced in such a way that the compensating force can be "adjusted." "Adjusting" the compensating force in this context can be understood as changing its magnitude. Pre-adjustment of the compensating force can be achieved, for example, by moving the inner magnetic rings away from or towards each other. After this pre-adjustment, the compensating force is fine-tuned using the adjusting element.

[0020] The adjusting element is, in particular, ring-shaped. Exactly one adjusting element may be provided. However, several, for example, exactly two, adjusting elements may also be provided. The fact that the adjusting element is "clamped" to the outer shell of the weight force compensator means, in this case, that the adjusting element applies a clamping force or forces acting against the radial direction to the outer shell. Thus, a force-fit connection is established between the adjusting element and the outer shell. The adjusting element encompasses the outer shell.

[0021] According to one embodiment, the adjusting element has spring-elastic deformable spring sections, wherein the spring sections are designed to apply a clamping force to the outer shell.

[0022] The clamping force or forces are oriented opposite to the radial direction. The term "spring-elastic deformable" in this context means, in particular, that the spring sections can be moved from an undeformed state to a deformed state by applying a force or forces. When this force or these forces cease to act on the spring sections, they automatically deform back from the deformed state to the undeformed state. In the undeformed state, the adjusting element applies the clamping force or forces to the outer shell. Any number of spring sections can be provided. At a minimum, exactly one spring section is provided. However, two or three spring sections can also be provided. Particularly preferred are exactly three spring sections, which are arranged evenly distributed around the central axis.

[0023] According to another embodiment, the spring sections each have a groove in which an adjustment tool for deforming the spring sections can be received.

[0024] The groove extends through each spring section to an inner surface of the adjusting element. The adjusting tool preferably has pin-shaped or knife-shaped engagement sections that can be inserted into the grooves. By rotating these engagement sections, for example by 90°, the spring sections can be deformed or expanded, so that they are moved from their undeformed state to their deformed state. In doing so, the adjusting element expands radially, allowing it to be moved along its central axis on the outer shell.

[0025] According to another embodiment, the adjusting element has ring sections, wherein the spring sections and the ring sections are arranged alternately.

[0026] This means, in particular, that a spring section is arranged between two ring sections and a ring section between two spring sections. Specifically, the ring sections and the spring sections are arranged alternately around their circumference. For example, exactly three ring sections and exactly three spring sections may be provided. However, it is also possible to provide exactly one ring section and exactly one spring section. The ring sections and the spring sections are preferably formed in one piece, in particular monolithically or as a single piece of material. "One piece" or "monolithic" in this context means that the ring sections and the spring sections do not form separate components, but rather a single component, namely the adjusting element. "Monolithic" or "as a single piece of material" in this context means, in particular, that the adjusting element is manufactured entirely from the same material. For example, a soft magnetic material may be used.Alternatively, the clamping force can also be applied by additional spring elements, which, for example, are not part of the adjustment element. In this case, the adjustment element can, for example, be made up of two half-shells which can be tensioned with the help of the additional spring elements in such a way that the adjustment element is clamped onto the outer shell.

[0027] According to another embodiment, the weight force compensator has a first adjusting element and a second adjusting element, wherein the first adjusting element and the second adjusting element are spaced apart from each other when viewed along a central axis of the weight force compensator.

[0028] To adjust the compensation force, the first and second adjustment elements can, for example, be moved towards or away from each other. Alternatively, exactly one adjustment element can be provided.

[0029] According to another embodiment, the passive magnetic circuit is arranged inside the outer shell, wherein the outer shell is arranged inside the adjusting element.

[0030] The outer casing is, in particular, tubular or hollow cylindrical. The outer magnetic ring is attached to the inside of the outer casing, while the adjusting element is attached to the outside of the outer casing. Thus, the outer casing is positioned between the adjusting element and the outer magnetic ring.

[0031] According to another embodiment, the adjusting element is positively connected to the outer shell.

[0032] For this purpose, the adjusting element can, for example, have a threaded structure on its inner surface and the outer casing a corresponding mating threaded structure. Alternatively, the adjusting element can also have groove-shaped recesses on its inner surface and the outer casing rib-shaped fins that can engage in the groove-shaped recesses. This arrangement can also be reversed.

[0033] Furthermore, a projection exposure system with such an optical system is proposed.

[0034] The optical system is preferably a projection optic of the projection exposure system. However, the optical system can also be an illumination system of the projection exposure system. The projection exposure system can be an EUV lithography system. "EUV" stands for "Extreme Ultraviolet" and refers to a wavelength of the working light between 0.1 nm and 30 nm. The projection exposure system can also be a DUV lithography system. "DUV" stands for "Deep Ultraviolet" and refers to a wavelength of the working light between 30 nm and 250 nm.

[0035] Furthermore, a method for adjusting the compensation force of the weight force compensator of the optical system described above is proposed. The method comprises the following steps: a) releasing the clamping force between the adjustment element and the outer shell using an adjustment tool, b) moving the adjustment element from its actual position to a desired position using the adjustment tool, and c) restoring the clamping force between the adjustment element and the outer shell using the adjustment tool.

[0036] The adjustment tool is thus designed to release the clamping force between the adjustment element and the outer shell, move the adjustment element along the outer shell to adjust the compensating force, and then reconnect the adjustment element to the outer shell at its target position by re-establishing the clamping force. The adjustment tool may, for example, include a measuring unit for detecting the actual position of the adjustment element. Furthermore, the adjustment tool may, for example, include a processing unit that can determine the actual position based on sensor data from the measuring unit. Finally, the adjustment tool may include a gripping and traversing unit designed to grip the adjustment element and move it along its central axis.Furthermore, the adjusting tool can have engagement sections as mentioned above, which are designed to engage in the grooves of the engagement element in order to deform the spring sections so that the adjusting element is radially expanded in order to be able to move it in step b).

[0037] According to one embodiment, in step a) the adjusting element is deformed using the adjusting tool in a spring-elastic manner.

[0038] This is achieved, for example, by rotating the engagement sections of the adjusting tool in the grooves of the adjusting element. These engagement sections can be, for example, pin-shaped or knife-shaped. This rotation of the engagement sections widens the adjusting element radially. In step c), the clamping between the adjusting element and the outer shell is restored by, for example, rotating the engagement sections back. This deforms the spring sections from their deformed state back to their undeformed state, causing the adjusting element to narrow radially again and apply the clamping force to the outer shell.

[0039] The term "one" here is not necessarily to be understood as restricting the number to exactly one element. Rather, it can also refer to multiple elements, such as two, three, or more. Similarly, every other numerical word used here should not be interpreted as restricting the number to the exact number stated. Instead, numerical deviations, both higher and lower, are possible unless otherwise indicated.

[0040] The embodiments and features described for the optical system apply accordingly to the proposed projection exposure system and the proposed method, and vice versa.

[0041] Other possible implementations of the invention also include combinations of features or embodiments described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned. In such cases, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0042] 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 with reference to preferred embodiments and the accompanying figures. Fig. Figure 1 shows a schematic meridional section of a projection exposure system for EUV projection lithography; Fig. Figure 2 shows a schematic view of an embodiment of an optical system for the projection exposure system according to Fig. 1; Fig. Figure 3 shows a schematic top view of the optical system according to Fig. 2; Fig. Figure 4 shows a schematic sectional view of an embodiment of a weight force compensator for the optical system according to Fig. 2; Fig. Figure 5 shows a schematic perspective view of an embodiment of an adjustment element for the weight force compensator according to Fig. 4; Fig. Figure 6 shows a schematic view of an embodiment of an adjustment tool for positioning the adjustment element according to Fig. 5; Fig. Figure 7 shows a schematic sectional view of another embodiment of a weight force compensator for the optical system according to Fig. 2; and Fig. Figure 8 shows a schematic block diagram of an embodiment of a method for adjusting a compensation force of the weight force compensator according to Fig. 4.

[0043] In the figures, identical or functionally equivalent elements have been labelled with the same reference symbols, unless otherwise indicated. Furthermore, it should be noted that the representations in the figures are not necessarily to scale.

[0044] Fig. Figure 1 shows an embodiment of a projection exposure system 1 (lithography system), in particular an EUV lithography system. One embodiment of the illumination system 2 of the projection exposure system 1 has, in addition to a light or radiation source 3, an illumination optic 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 rest of the illumination system 2. In this case, the illumination system 2 does not include the light source 3.

[0045] A reticule 7 arranged in the object field 5 is exposed. The reticule 7 is held by a reticule holder 8. The reticule holder 8 can be moved, particularly in a scanning direction, via a reticule displacement drive 9.

[0046] In the Fig. 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 scan direction runs in the Fig. 1 along the y-direction y. The z-direction z runs perpendicular to the object plane 6.

[0047] The projection exposure system 1 comprises a projection optic 10. The projection optic 10 serves to image the object field 5 onto an image field 11 in an image plane 12. The image plane 12 is 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.

[0048] A structure on the reticulum 7 is imaged onto a photosensitive layer of a wafer 13 located in the image plane 12 within the image field 11. The wafer 13 is held by a wafer holder 14. The wafer holder 14 can be moved, particularly along the y-direction y, via a wafer transfer drive 15. The movement of the reticulum 7 via the reticulum transfer drive 9 and of the wafer 13 via the wafer transfer drive 15 can be synchronized.

[0049] Light source 3 is an EUV radiation source. 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 a wavelength in the range between 5 nm and 30 nm. 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. Light source 3 can be a free-electron laser (FEL).

[0050] 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 hyperboloid reflective surfaces. The at least one reflective surface of the collector 17 can be illuminated by the illumination radiation 16 at grazing incidence (GI), i.e., with angles of incidence greater than 45°, or at normal incidence (NI), i.e., with angles of incidence less than 45°. The collector 17 can be structured and / or coated to optimize its reflectivity for the useful radiation and to suppress stray light.

[0051] 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.

[0052] The illumination optics 4 comprise a deflecting mirror 19 and, downstream in the beam path, a first faceted mirror 20. The deflecting mirror 19 can be a planar deflecting mirror or, alternatively, a mirror with an effect that influences the beam shape beyond the mere deflection effect. Alternatively or additionally, the deflecting mirror 19 can be designed as a spectral filter that separates a useful wavelength of the illumination radiation 16 from stray light of a different wavelength. If the first faceted mirror 20 is arranged in a plane of the illumination optics 4 that is optically conjugate to the object plane 6 as the field plane, it is also referred to as a field faceted mirror. The first faceted mirror 20 comprises a plurality of individual first facets 21, which can also be referred to as field facets. Of these first facets 21, the following are in the Fig. 1 only some examples are shown.

[0053] The first facets 21 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or semicircular border contour. The first facets 21 can be designed as planar facets or alternatively as convexly or concavely curved facets.

[0054] As is known, for example, from DE 10 2008 009 600 A1, the first facets 21 can themselves each 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.

[0055] Between the collector 17 and the deflecting mirror 19, the illumination radiation 16 runs horizontally, i.e. along the y-direction y.

[0056] In the beam path of the illumination optics 4, a second faceted mirror 22 is arranged downstream of the first faceted mirror 20. If the second faceted mirror 22 is arranged in a pupil plane of the illumination optics 4, it is also referred to as a pupil faceted mirror. The second faceted 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 faceted mirror 20 and the second faceted mirror 22 is also referred to as a specular reflector. Specular reflectors are known from US 2006 / 0132747 A1, EP 1 614 008 B1, and US 6,573,978.

[0057] 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.

[0058] The second facets 23 can also be macroscopic facets, which may, for example, have round, rectangular, or hexagonal edges, or alternatively, facets composed of micromirrors. Reference is also made to DE 10 2008 009 600 A1 in this regard.

[0059] The second facets 23 can have planar or alternatively convex or concave curved reflective surfaces.

[0060] The illumination optics 4 thus form a double-faceted system. This basic principle is also known as a honeycomb condenser (English: Fly's Eye Integrator).

[0061] It can be advantageous not to arrange the second faceted mirror 22 exactly in a plane that is optically conjugate to a pupil plane of the projection optics 10. In particular, the second faceted 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.

[0062] With the aid of the second faceted mirror 22, the individual first facets 21 are imaged into the object field 5. The second faceted mirror 22 is the last beam-shaping, or indeed the last, mirror for the illumination radiation 16 in the beam path before the object field 5.

[0063] In another embodiment of the illumination optics 4, not shown, a transmission optic can be arranged in the beam path between the second facet mirror 22 and the object field 5, which contributes in particular to imaging the first facets 21 into the object field 5. The transmission optic can have exactly one mirror, or alternatively two or more mirrors, arranged one behind the other in the beam path of the illumination optics 4. The transmission optic can, in particular, comprise one or two mirrors for normal incidence (NI mirrors) and / or one or two mirrors for grazing incidence (GI mirrors).

[0064] The lighting optics 4, in the version shown in the Fig. Figure 1 shows exactly three mirrors after the collector 17, namely the deflecting mirror 19, the first faceted mirror 20 and the second faceted mirror 22.

[0065] In a further embodiment of the lighting optics 4, the deflecting mirror 19 can also be omitted, so that the lighting optics 4 after the collector 17 can then have exactly two mirrors, namely the first faceted mirror 20 and the second faceted mirror 22.

[0066] The mapping of the first facets 21 by means of the second facets 23 or with the second facets 23 and a transmission optic into the object plane 6 is regularly only an approximate mapping.

[0067] The projection optics 10 comprise a plurality of mirrors Mi, which are numbered according to their arrangement in the beam path of the projection exposure system 1.

[0068] In the Fig. In the example shown, the projection optics 10 comprise six mirrors M1 to M6. Alternatives with four, eight, ten, twelve, or any other number of mirrors Mi are also possible. The projection optics 10 is a doubly obscured optic. The penultimate mirror M5 and the last mirror M6 each have an aperture 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.

[0069] The reflective surfaces of the mirrors Mi can be designed as freeform surfaces without an axis of rotational symmetry. Alternatively, the reflective surfaces of the mirrors Mi can be designed as aspherical surfaces with exactly one axis of rotational symmetry of the reflective 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.

[0070] 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.

[0071] The projection optics 10 can be anamorphic. In particular, they have different magnifications βx, βy in the x and y directions. The two magnifications βx, βy of the projection optics 10 are preferably (βx, βy) = (+ / - 0.25, + / - 0.125). A positive magnification β indicates a projection without image inversion. A negative magnification β indicates a projection with image inversion.

[0072] The projection optics 10 thus lead to a reduction in the x-direction x, that is, in the direction perpendicular to the scan direction, in a ratio of 4:1.

[0073] The projection optics 10 lead to a reduction of 8:1 in the y-direction y, that is, in the scan direction.

[0074] Other magnification ratios are also possible. Magnification ratios with the same sign and absolute values ​​in the x and y directions (x, y), for example with absolute values ​​of 0.125 or 0.25, are also possible.

[0075] 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, depending on the design of the projection optics 10, different. 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.

[0076] Each of the second facets 23 is assigned to exactly one of the first facets 21 to form an illumination channel for illuminating the object field 5. This can result, in particular, in illumination according to Köhler's principle. The far field is divided into a multitude of object fields 5 with the help of the first facets 21. The first facets 21 generate a plurality of images of the intermediate focus on the second facets 23 assigned to each of them.

[0077] The first facets 21 are each superimposed on a corresponding second facet 23 to illuminate the object field 5 on the reticle 7. The illumination of the object field 5 is particularly homogeneous. It preferably exhibits a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.

[0078] The illumination of the entrance pupil of the projection optics 10 can be geometrically defined by arranging the second facets 23. By selecting the illumination channels, in particular the subset of the second facets 23 that carry 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 filling.

[0079] Another preferred pupil uniformity in the area of ​​defined illuminated sections of an illumination pupil of the illumination optics 4 can be achieved by a redistribution of the illumination channels.

[0080] Further aspects and details of the illumination of the object field 5 and, in particular, the entrance pupil of the projection optics 10 are described below.

[0081] The projection optics 10 can, in particular, have a homocentric entrance pupil. This can be accessible. It can also be inaccessible.

[0082] The entrance pupil of the projection optics 10 cannot always be illuminated exactly by the second faceted mirror 22. When the projection optics 10 image the center of the second faceted mirror 22 telecentrically onto the wafer 13, the aperture rays often do not intersect at a single point. However, a surface can be found where the pairwise determined separation of the aperture rays is minimized. This surface represents the entrance pupil or a surface conjugate to it in real space. In particular, this surface exhibits a finite curvature.

[0083] The projection optics 10 may 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 faceted mirror 22 and the reticle 7. This optical element can accommodate the different positions of the tangential and sagittal entrance pupils.

[0084] During the Fig. In the arrangement of the components of the illumination optics 4 shown in Figure 1, the second faceted mirror 22 is arranged in a plane conjugate to the entrance pupil of the projection optics 10. The first faceted mirror 20 is arranged tilted relative to the object plane 6. The first faceted mirror 20 is arranged tilted relative to an arrangement plane defined by the deflecting mirror 19. The first faceted mirror 20 is arranged tilted relative to an arrangement plane defined by the second faceted mirror 22.

[0085] Fig. Figure 2 shows a schematic view of an embodiment of an optical system 100 for the projection exposure system 1. Fig. Figure 3 shows a schematic top view of optical system 100. The following section refers to the Fig. 2 and Fig. 3 referenced simultaneously.

[0086] The optical system 100 can be a projection optic 10 as previously described, or part of such a projection optic 10. Therefore, the optical system 100 can also be referred to as a projection optic. However, the optical system 100 can also be an illumination system 2 as previously described, or part of such an illumination system 2. Therefore, the optical system 100 can alternatively be referred to as an illumination system. In the following, however, it will be assumed that the optical system 100 is a projection optic 10, or part of such a projection optic 10. The optical system 100 is suitable for EUV lithography. However, the optical system 100 can also be suitable for DUV lithography.

[0087] The optical system 100 can comprise several optical elements 102, of which in the Fig. 2 and Fig. However, only one is shown in Figure 3. Therefore, only one optical element 102 will be discussed below. The optical element 102 can be one of the mirrors M1 to M6. The optical element 102 comprises a substrate 104 and an optically effective surface 106, for example, a mirror surface. The substrate 104 can also be referred to as the mirror substrate. The substrate 104 can comprise glass, ceramic, glass-ceramic, or other suitable materials. The optical element 102 has a weight force G. In the orientation of the Fig. 2. The weight force G acts in the opposite direction to the z-direction.

[0088] The optically effective surface 106 is provided on a front face 108 of the optical element 102, in particular on the substrate 104. The optically effective surface 106 can be realized by means of a coating applied to the front face 108. The optically effective surface 106 is a mirror surface. The optically effective surface 106 is suitable for reflecting illumination radiation 16, in particular EUV radiation, during operation of the optical system 100.

[0089] The optically effective area 106 can be viewed from above according to Fig. 3. They may have an oval or elliptical geometry. The optical element 102 or the substrate 104 may have a triangular geometry. In principle, however, the geometry is arbitrary.

[0090] The optical element 102 has a back surface 110 facing away from the optically effective surface 106 or the front surface 108. The back surface 110 has no defined optical properties. In particular, this means that the back surface 110 is not a mirror surface and therefore has no reflective properties.

[0091] Several mirror sockets 112, 114, 116 are provided on the rear side 110. Specifically, there is a first mirror socket 112, a second mirror socket 114, and a third mirror socket 116. In other words, the optical element 102 comprises exactly three mirror sockets 112, 114, 116. The mirror sockets 112, 114, 116 can be geometrically identical. The mirror sockets 112, 114, 116 are cylindrical and extend in the orientation of the Fig. 2 protrudes from the underside of the rear side 110. The mirror sockets 112, 114, 116 form the vertices of an imaginary triangle.

[0092] The optical element 102 or the optically effective surface 106 has six degrees of freedom, namely three translational degrees of freedom each along a first spatial direction or x-direction x, a second spatial direction or y-direction y, and a third spatial direction or z-direction z, as well as three rotational degrees of freedom each around the x-direction x, the y-direction y, and the z-direction z. That is, the position and orientation of the optical element 102 or the optically effective surface 106 can be determined or described using the six degrees of freedom.

[0093] The "position" of the optical element 102 or the optically effective surface 106 refers in particular to its coordinates or the coordinates of a measuring point provided on the optical element 102 with respect to the x-direction x, the y-direction y, and the z-direction z. The "orientation" of the optical element 102 or the optically effective surface 106 refers in particular to its tilt with respect to the three directions x, y, z. That is, the optical element 102 or the optically effective surface 106 can be tilted about the x-direction x, the y-direction y, and / or the z-direction z.

[0094] This results in six degrees of freedom for the position and orientation of the optical element 102 or the optically effective surface 106. A "position" of the optical element 102 or the optically effective surface 106 encompasses both its position and its orientation. The term "position" can therefore be replaced by the phrase "position and orientation" and vice versa.

[0095] In the Fig. Figure 2 shows the current position (IL) of optical element 102 with solid lines, and the desired position (SL) of optical element 102 with dashed lines and the reference symbol 102'. Optical element 102 can be moved from its current position (IL) to the desired position (SL) and vice versa. For example, optical element 102 in the desired position (SL) meets certain optical specifications or requirements that optical element 102 in its current position (IL) does not meet.

[0096] To move the optical element 102 from its actual position IL to its desired position SL, the optical system 100 includes an adjustment device 118. The adjustment device 118 is configured to adjust the optical element 102. In this context, "adjustment" or "alignment" refers specifically to changing the position of the optical element 102. For example, the optical element 102 can be moved from its actual position IL to its desired position SL and vice versa using the adjustment device 118. The adjustment or alignment of the optical element 102 can thus be performed in all six degrees of freedom mentioned above using the adjustment device 118.

[0097] The adjustment device 118 comprises several actuator assemblies 120, 122, 124, which are located in the Fig. Figure 2 is shown only in a highly schematic form. The actuator assemblies 120, 122, 124 can also be referred to as adjusting element assemblies or bipods. Each mirror socket 112, 114, 116 is assigned an actuator assembly 120, 122, 124. This means, in particular, that exactly three actuator assemblies 120, 122, 124 are provided. With the three actuator assemblies 120, 122, 124, adjustment of the optical element 102 in all six degrees of freedom is possible.

[0098] The first mirror socket 112 is assigned a first actuator assembly 120. The second mirror socket 114 is assigned a second actuator assembly 122. The third mirror socket 116 is assigned a third actuator assembly 124. The actuator assemblies 120, 122, and 124 are identical in construction. Therefore, only the first actuator assembly 120 and the first mirror socket 112 will be discussed below; these will be referred to simply as actuator assembly 120 and mirror socket 112, respectively. All subsequent statements concerning actuator assembly 120 are applicable to actuator assemblies 122 and 124, and vice versa.

[0099] The actuator assembly 120 is coupled to the mirror socket 112 via a connection point 126. Furthermore, the actuator assembly 120 is coupled to a fixed world 132 via two additional connection points 128 and 130. The fixed world 132 can be a force frame or another immobile structure.

[0100] The actuator arrangement 120 comprises two actuators 134, 136, in particular a first actuator 134 and a second actuator 136. The six degrees of freedom of the optical element 102 can be adjusted using all actuators 134, 136 of all actuator arrangements 120, 122, 124. The actuators 134, 136 can also be referred to as adjusting elements or actuators.

[0101] Both actuators 134 and 136 are connected to the mirror socket 112 at connection point 126. Furthermore, actuators 134 and 136 are connected to the fixed world 132 via connection points 128 and 130. Actuators 134 and 136 can be controlled by a control unit 138 of the adjustment device 118 to adjust the optical element 102. All actuators 134 and 136 of all actuator arrangements 120, 122, and 124 are operatively connected to the control unit 138, so that the control unit 138 can adjust the optical element 102 in all six degrees of freedom by appropriately controlling the actuators 134 and 136. This can be done based on sensor signals from a sensor system not shown, which can detect the actual position IL and the target position SL of the optical element 102.

[0102] The optical element 102 is accordingly mounted on the actuator assemblies 120, 122, 124 or on the actuators 134, 136. To minimize heat generation in the actuators 134, 136, the weight force G of the optical element 102 is generally absorbed by a weight force compensator (not shown). Each actuator assembly 120, 122, 124 is assigned such a weight force compensator. A compensating force generated by the respective weight force compensator, which acts against the weight force G, can be produced by a passive magnetic circuit.

[0103] Fig. Figure 4 shows a schematic sectional view of an embodiment of a weight force compensator 200A as previously mentioned.

[0104] As mentioned previously, each of the actuator arrangements 120, 122, 124 can have such a weight force compensator 200A. The weight force compensator 200A is essentially rotationally symmetrical about a symmetry or central axis 202. The weight force compensator 200A also has a radial direction 204, which is oriented perpendicular to and away from the central axis 202.

[0105] The 200A weight force compensator comprises a housing 206, which is located in the Fig. 4 is shown only in plate form. However, the housing 206 can completely encapsulate the weight force compensator 200A. The housing 206 carries a tubular or hollow cylindrical outer shell 208. The outer shell 208 has an outer surface 210 and an inner surface 212. The outer shell 208 is firmly connected to the housing 206.

[0106] Furthermore, the weight force compensator 200A comprises a tubular or hollow cylindrical inner element 214, which is arranged within the outer shell 208. This means, in particular, that the inner element 214 is enclosed by the outer shell 208 when viewed along the radial direction 204. The inner element 214 comprises an outer surface 216 facing the inner surface 212 of the outer shell 208 and an inner surface 218 facing away from the outer surface 216. The inner element 214 is not directly connected to the housing 206.

[0107] The inner element 214 is connected to the outer shell 208 by means of a lower or first leaf spring element 220 and an upper or second leaf spring element 222. The leaf spring elements 220 and 222 are each attached to the ends of the inner element 214. The leaf spring elements 220 and 222 can be disc-shaped. The leaf spring elements 220 and 222 can have any recesses or cutouts that allow axial movement of the inner element 214 along the central axis 202 relative to the outer shell 208. However, the leaf spring elements 220 and 222 prevent movement of the inner element 214 along the radial direction 204 as well as tilting of the inner element 214 relative to the outer shell 208.

[0108] An actuating rod or pin 224, rotationally symmetrical about the central axis 202, is attached to the inner element 214. The actuating pin 224 applies a compensating force K, counteracting the weight force G, to the respective attachment point 126 of the respective actuator arrangement 120, 122, 124 in order to compensate for the weight force G of the optical element 102. The actuating pin 224 passes through the inner element 214 and is connected to it at an end face 226 of the inner element 214 facing away from the second leaf spring element 222. The first leaf spring element 220 is also coupled to this end face 226.

[0109] To generate the compensating force K, the weight force compensator 200A has a passive magnetic circuit 228, which includes an outer magnetic ring 230 with a north pole N and a south pole S, a lower or first inner magnetic ring 232 with a north pole N and a south pole S, and an upper or second inner magnetic ring 234 with a north pole N and a south pole S. Viewed along the radial direction 204, the inner magnetic rings 232 and 234 are arranged inside the outer magnetic ring 230. Viewed along the central axis 202, the first inner magnetic ring 232 and the second inner magnetic ring 234 are spaced apart from each other. The first inner magnetic ring 232 and the second inner magnetic ring 234 project axially beyond the outer magnetic ring 230 when viewed along the central axis 202.

[0110] The passive magnetic circuit 228 described above is only an example. There are also other passive magnetic circuit arrangements for force compensation, which also offer the possibility of fine adjustment via geometric displacement of soft magnetic rings. For example, such a passive magnetic circuit (not shown) could have an outer magnetic ring comprising several, in particular three, radially magnetized rings and also several, in particular two, radially magnetized inner magnetic rings. The function, however, is identical to that of the passive magnetic circuit 228 described above.

[0111] The outer magnetic ring 230 is connected to the inner surface 212 of the outer shell 208. The inner magnetic rings 232, 234 are connected to the outer surface 216 of the inner element 214. The passive magnetic circuit 228 generates the compensating force K acting along the central axis 202, which at least partially compensates for the weight force G of the optical element 102.

[0112] To adjust or set the compensation force K, particularly for pre-adjustment, the inner magnetic rings 232, 234 can be moved axially relative to each other and relative to the outer magnetic ring 230 along the central axis 202. This changes the magnetic field generated by the passive magnetic circuit 228, which in turn affects the compensation force K. However, this pre-adjustment by moving the inner magnetic rings 232, 234 is only possible when the weight force compensator 200A is installed. Fine-tuning the compensation force K to adapt it to the specific application is therefore difficult.

[0113] For fine-tuning or adjustment (typically in a force range < 5%) of the total compensation force K exerted by the weight force compensator 200A, in particular for compensation force adjustment, additional adjustment elements 236, 238 can be used, which bear against the outer surface 210 of the outer shell 208. Specifically, a lower or first adjustment element 236 and an upper or second adjustment element 238 are provided. The adjustment elements 236, 238 are identical in construction. The adjustment elements 236, 238 are ring-shaped and rotate completely around the central axis 202. The adjustment elements 236, 238 are made of a soft magnetic material. The adjustment elements 236, 238 can also be referred to as adjustment rings or soft magnetic rings.

[0114] By shifting the adjustment elements 236, 238 along the central axis 202, the course of magnetic field lines generated by the passive magnetic circuit 228 can be influenced, and thus the compensation force K exerted on the optical element 102 can ultimately be manipulated continuously and reversibly. Fine adjustment of the compensation force K is therefore possible using the adjustment elements 236, 238.

[0115] In particular, the magnetic field of the passive magnetic circuit 228 can first be preset for the pre-adjustment by means of a distance adjustment of the inner magnetic rings 232, 234 to each other and then varied in a small adjustment range by means of the adjustment elements 236, 238, in that the adjustment elements 236, 238 exert a weakening or strengthening effect on the overall generated magnetic field and thus on the compensation force K transmitted to the optical element 102, depending on the specific requirements.

[0116] In particular, the adjusting elements 236, 238 can each be made from one component in the Fig. The actual position IP, shown with solid lines, is moved to the target position SP, shown with dashed lines and designated with reference symbols 236', 238'. This positioning can be stepless. For example, only one of the adjustment elements 236, 238 can be moved.

[0117] The adjusting elements 236, 238 are clamped onto the outer shell 208 and exert clamping forces F on the outer shell 208 oriented opposite to the radial direction 204. This means, in particular, that a force-fit connection exists between the adjusting elements 236, 238 and the outer shell 208. Additionally, a positive-locking connection may also exist. In this case, for example, the outer surface 210 may be provided with a threaded structure, circumferential grooves, or the like. Accordingly, the adjusting elements 236, 238 may also be provided on their inner surfaces with a corresponding threaded structure, circumferential ribs, or the like.

[0118] Fig. Figure 5 shows a schematic perspective view of an embodiment of a first adjustment element 236 as previously mentioned.

[0119] As mentioned previously, the adjustment elements 236 and 238 are identical in construction. Therefore, only the first adjustment element 236 will be discussed below. All subsequent explanations pertaining to the first adjustment element 236 are applicable to the second adjustment element 238 and vice versa.

[0120] The first adjusting element 236 is ring-shaped and, in this case, comprises several ring sections 240, 242, 244. The number of ring sections 240, 242, 244 is arbitrary. For example, exactly three such ring sections 240, 242, 244 are provided. At least one such ring section 240, 242, 244 is provided. The ring sections 240, 242, 244 are connected to each other by means of spring sections 246, 248, 250. A spring section 246, 248, 250 is always arranged between two ring sections 240, 242, 244, and a ring section 240, 242, 244 is always arranged between two spring sections 246, 248, 250. The spring sections 246, 248, 250 generate the radial clamping forces F.

[0121] The ring sections 240, 242, 244 and the spring sections 246, 248, 250 are joined together in one piece, in particular in one piece or monolithically. "One piece" or "monolithic" in this context means, in particular, that the ring sections 240, 242, 244 and the spring sections 246, 248, 250 do not form separate components, but rather a single component, namely the first adjusting element 236. "One piece" or "monolithic" in this context means, in particular, that the first adjusting element 236 is made entirely of the same material, namely a soft magnetic material.

[0122] The spring sections 246, 248, 250 are spring-elastically deformable. This means, in particular, that the spring sections 246, 248, 250 can be moved from an undeformed state to a deformed state by the application of external forces. When these forces are no longer acting on the spring sections 246, 248, 250, they deform themselves back from the deformed state to the undeformed state. In the undeformed state of the spring sections 246, 248, 250, the first adjusting element 236 applies the clamping forces F to the outer surface 210 of the outer shell 208, so that the first adjusting element 236 is axially fixed to the outer shell 208 when viewed along the central axis 202.

[0123] Each spring section 246, 248, 250 has an arbitrarily shaped groove 252, 254, 256 extending along the central axis 202 and opening towards an inner surface 258, with which the first adjusting element 236 abuts the outer surface 210. An engagement element, for example in the form of a knife-like or eccentric pin or rod, can be inserted into each of these grooves 252, 254, 256 and then rotated, for example, by 90°. This rotation moves the spring sections 246, 248, 250 from their undeformed state to their deformed state, causing the first adjusting element 236 to expand radially along the radial direction 204. This makes it possible to move the first adjustment element 236 along the central axis 202, for example to move the first adjustment element 236 from its actual position IP to its target position SP.

[0124] Fig. Figure 6 shows a schematic view of an embodiment of an adjustment tool 260 for positioning the adjustment elements 236, 238 on the outer shell 208.

[0125] The adjusting tool 260 is suitable for releasing the clamping between the adjusting elements 236, 238 and the outer shell 208, moving the adjusting elements 236, 238 along the central axis 202, and then locking them in place by re-establishing the clamping. For example, both adjusting elements 236, 238 can be moved simultaneously from their respective actual position IP to their respective target position SP and locked there. Alternatively, it is also possible to position first the first adjusting element 236 and then the second adjusting element 238, or vice versa, on the outer shell 208.

[0126] The adjusting tool 260 can, for example, be placed over the weight force compensator 200A. The adjusting tool 260 can accommodate the adjusting elements 236 and 238. Accordingly, the adjusting tool 260 can be ring-shaped or tubular.

[0127] The adjusting tool 260, for example, comprises several first engagement elements 262, 264, 266, as previously mentioned, which are configured to engage in the grooves 252, 254, 256 of the first adjusting element 236 in order to radially expand it, move it along the central axis 202, and position it in its target position SP. Optionally, corresponding second engagement elements 268, 270, 272 can also be assigned to the second adjusting element 238. Alternatively, for example, the first adjusting element 236 can be positioned first, followed by the second adjusting element 238. In this case, only the first engagement elements 262, 264, 266 are required. The engagement elements 262, 264, 266, 268, 270, 272 can have the previously mentioned knife-like or eccentric geometry.

[0128] The adjustment tool 260 further comprises a measuring unit 274, with the aid of which it is possible to determine a respective position, for example the respective actual position IP, of the adjustment elements 236, 238 on the outer shell 208. For this purpose, the measuring unit 274 can, for example, have any sensors or the like.

[0129] The adjustment tool 260 can optionally also include a computing unit 276. For example, the positioning of the adjustment elements 236, 238 can be automated using the computing unit 276 based on data from the measuring unit 274.

[0130] The adjusting tool 260 can further include a gripping and traversing unit 278, with the aid of which the adjusting elements 236, 238 can be gripped and moved along the central axis 202 in the deformed state of the spring sections 246, 248, 250.

[0131] The fine adjustment procedure can be carried out as follows. First, the adjustment tool 260 is placed on the weight force compensator 200A. The adjustment elements 236 and 238 can be accessed via openings on the front of the housing 206. The adjustment elements 236 and 238 are then unlocked using the engagement elements 262, 265, 266, 268, 270, and 272. This is achieved by releasing the clamping force through deformation of the spring sections 246, 248, and 250 using the engagement elements 262, 264, 266, 268, 270, and 272.

[0132] Simultaneously, the adjusting tool 260 grips the adjusting elements 236, 238 with the aid of the gripping and traversing unit 278. The adjusting elements 236, 238 are then moved to their desired position, that is, from their actual position IP to their target position SP. Subsequently, the adjusting elements 236, 238 are locked again by rotating the engagement elements 262, 264, 266, 268, 270, 272 in the grooves 252, 254, 256 of the adjusting elements 236, 238 from a deflected position back to a starting position. This returns the spring sections 246, 248, 250 from the deformed state back to the undeformed state. The adjusting tool 260 can then be removed.

[0133] The adjustment tool 260 therefore requires complex kinematic functions. However, these kinematic functions are only needed once and do not need to be included or implemented in the weight force compensator 200A. This results in a significantly simplified design of the weight force compensator 200A, leading to lower costs. The position of the adjustment elements 236 and 238 can also be determined using the measuring unit 274 integrated into the adjustment tool 260. Advantageously, this eliminates any dynamic impact. A complete displacement mechanism for the adjustment elements 236 and 238 is thus implemented in the adjustment tool 260.

[0134] The weight force compensator 200A can have the modifications or further developments described below. The number of spring sections 246, 248, 250, and thus also of grooves 252, 254, 256, can also be changed to exactly two. The unlocking of the adjusting elements 236, 238 could also be achieved via opposing wedges. Furthermore, the clamping can also be realized via additional spring elements, which in this case are preferably not integral parts of the adjusting elements 236, 238. The principle would also work in reverse. Instead of the pre-tensioned adjusting elements 236, 238, an active locking or clamping mechanism could also be used. The clamping forces F can be improved by means of surface structures, grooves, or similar features.

[0135] Fig. Figure 7 shows a schematic sectional view of another embodiment of a weight force compensator 200B.

[0136] The weight force compensator 200B differs from the weight force compensator 200A only in that the weight force compensator 200B does not have adjustment elements 236, 238 which are spring-elastic and thus expandable, but rather a lower or first adjustment element 280 and an upper or second adjustment element 282 which do not rest against the outer surface 210 of the outer shell 208, but are arranged radially spaced from it. In other words, a circumferential gap is provided between the adjustment elements 280, 282 and the outer surface 210.

[0137] In particular, the adjusting elements 280, 282 can each, for example, consist of one in the Fig. The actual position IP, shown with solid lines, is moved to the target position SP, shown with dashed lines and designated with reference symbols 280', 282'. This positioning can be stepless. For example, only one of the adjustment elements 280, 282 can be moved.

[0138] To influence the compensation force K and to move the adjusting elements 280, 282 from their respective actual position IP to their desired target position SP, the weight force compensator 200B has an adjustment device 284. The adjustment device 284 comprises several lower or first threaded spindles 286, which are assigned to the first adjusting element 280. The first threaded spindles 286 are arranged evenly distributed around the central axis 202. For example, three such first threaded spindles 286 are assigned to the first adjusting element 280. In this case, the first threaded spindles 286 are each arranged at an angle of 120° to each other. The first threaded spindles 286 prevent the first adjusting element 280 from rotating about the central axis 202.

[0139] Each first threaded spindle 286 comprises an actuating section 288, a threaded rod 290 with a thread, in particular an external thread, rotatably mounted on the housing 206, and an engagement element 292, which is attached to the first adjusting element 280 or is part of the first adjusting element 280. The engagement element 292 can be a thread provided in the first adjusting element 280, in particular an internal thread.

[0140] The two adjusting elements 280, 282 can be axially spring-loaded along the central axis 202 by means of springs, in particular tension springs. These springs generate axial tension to eliminate bearing play and / or thread play and to create a constant preload in the threads for self-locking.

[0141] If the first threaded spindles 286 are now rotated synchronously or simultaneously at their respective actuating section 288, the respective threaded rod 290 moves in the associated engagement element 292, whereby the first adjusting element 280 can be moved or shifted along the central axis 202, for example, from the actual position IP to the target position SP.

[0142] The adjusting device 284 further comprises several upper or second threaded spindles 294, which are assigned to the second adjusting element 282. For example, three such second threaded spindles 294 are provided, which are arranged evenly distributed around the central axis 202. The first threaded spindles 286 and the second threaded spindles 294 are arranged alternately.

[0143] Every second threaded spindle 294 comprises an actuating section 296, a threaded rod 298 attached to the actuating section 296, and an engagement element 300, which is attached to the second adjusting element 282 or is part of the second adjusting element 182. The second threaded spindles 294 are mounted on the housing 206.

[0144] If the second threaded spindles 294 are rotated synchronously or simultaneously at their respective actuating section 296, the respective threaded rod 298 rotates in the corresponding engagement element 300, thereby moving or displacing the second adjusting element 282 along the central axis 202 from its actual position IP to its target position SP. The two adjusting elements 280, 282 can be positioned simultaneously or sequentially.

[0145] Fig.Figure 8 shows a schematic block diagram of an embodiment of a method for adjusting the compensation force K of the weight force compensator 200A.

[0146] In the process, in step S1, the clamping between the respective adjusting element 236, 238 and the outer shell 208 is released using the adjusting tool 260. For this purpose, in step S1, the adjusting element 236, 238 can be deformed spring-elastically using the adjusting tool 260, as previously explained with reference to the spring sections 246, 248, 250. This causes the respective adjusting element 236, 238 to expand along the radial direction 204.

[0147] In particular, during step S1, the engagement elements 262, 264, 266, 268, 270, 272 can be moved, in particular rotated, from their initial position, in which the spring sections 246, 248, 250 are in their undeformed state, into their deflected position, causing the spring sections 246, 248, 250 to deform elastically and releasing the clamping. Before step S1, the adjusting tool 260 can be applied, in particular, to one of the adjusting elements 236, 238 or to both adjusting elements 236, 238 simultaneously.

[0148] In step S2, the adjusting element 236, 238 is moved or repositioned from its actual position IP to the desired target position SP using the adjusting tool 260, in particular using the gripping and traversing unit 278. The respective adjusting element 236, 238 is moved along the central axis 202.

[0149] In step S3, the clamping between the respective adjusting element 236, 238 and the outer shell 208 is restored using the adjusting tool 260. This is achieved by moving the engagement elements 262, 264, 266, 268, 270, 272 from their deflected position, in which the spring sections 246, 248, 250 are in their deformed state, back to their initial position, in particular by rotating them. This causes the spring sections 246, 248, 250 to return from their deformed state to their undeformed state on their own. The adjusting tool 260 is then removed.

[0150] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. REFERENCE MARK LIST 1 Projection exposure system 2 Lighting system 3 light source 4 Lighting optics 5 object field 6 Object level 7 reticles 8 label holders 9 Reticle displacement drive 10 Projection optics 11 Image field 12 Image plane 13 wafers 14 wafer holders 15 wafer transfer drive 16 Lighting radiation 17 Collector 18 Intermediate focus plane 19 deflecting mirrors 20 first faceted mirror 21 first facet 22 second faceted mirror 23 second facet 100 optical system 102 optical element 102' optical element 104 Substrat 106 optically effective areas 108 Front 110 reverse 112 Mirror socket 114 Mirror socket 116 Mirror socket 118 Adjustment device 120 actuator arrangement 122 Actuator arrangement 124 Actuator arrangement 126 Connection point 128 Connection point 130 Connection point 132 solid world 134 Actuator 136 Actuator 138 Control and regulating unit 200A weight force compensator 200B Weight Force Compensator 202 Central axis 204 Radial direction 206 cases 208 Outer shell 210 outdoor area 212 interior surface area 214 Interior element 216 outdoor area 218 interior surface area 220 leaf spring element 222 Leaf spring element 224 Actuator pin 226 Front 228 Passive magnetic circuit 230 magnetic ring 232 Magnetic ring 234 Magnetic ring 236 Adjustment element 236' Adjustment element 238 Adjustment element 238' Adjustment element 240 ring section 242 Ring section 244 Ring section 246 Spring section 248 Spring section 250 spring section 252 Nut 254 Nut 256 Nut 258 interior surface area 260 Adjustment tool 262 Intervention element 264 Intervention element 266 Intervention element 268 Intervention element 270 Intervention element 272 Intervention element 274 Unit of measurement 276 computing units 278 Gripping and traversing unit 280 Adjustment element 280' Adjustment element 282 Adjustment element 282' Adjustment element 284 Adjustment device 286 Threaded spindle 288 Actuating section 290 threaded rod 292 Intervention element 294 Threaded spindle 296 Actuating section 298 threaded rod 300 intervention element G Weight force F clamping force K compensation force IL Current Situation IP Actual Position North Pole South Pole SL target position SP Target Position S1 step S2 step S3 step M1 mirror M2 mirrors M3 mirror M4 mirrors M5 mirror M6 mirrors x x-direction y y-direction z z-direction QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 10 2008 009 600 A1 [0054, 0058] US 2006 / 0132747 A1

[0056] EP 1 614 008 B1

[0056] US 6,573,978

[0056] DE 10 2017 220 586 A1

[0061] US 2018 / 0074303 A1

[0075]

Claims

[1] Optical system (100) for a projection exposure system (1), comprising an optical element (102, 102'), and a weight force compensator (200A) to compensate for a weight force (G) of the optical element (102, 102'), wherein the weight force compensator (200A) has a passive magnetic circuit (228) for generating a compensation force (K) that counteracts the weight force (G), wherein the weight force compensator (200A) has an adjustment element (236, 236', 238, 238') for adjusting the compensation force (K), and wherein the adjusting element (236, 236', 238, 238') is clamped on the outside of an outer shell (208) of the weight force compensator (200A). [2] Optical system according to claim 1, wherein the adjusting element (236, 236', 238, 238') has spring-elastic deformable spring sections (246, 248, 250), and wherein the spring sections (246, 248, 250) are configured to apply a clamping force (F) to the outer shell (208). [3] Optical system according to claim 2, wherein the spring sections (246, 248, 250) each have a groove (252, 254, 256) in which an adjustment tool (260) for deforming the spring sections (246, 248, 250) can be received. [4] Optical system according to claim 2 or 3, wherein the adjusting element (236, 236', 238, 238') has ring sections (240, 242, 244), and wherein the spring sections (246, 248, 250) and the ring sections (240, 242, 244) are arranged alternately. [5] Optical system according to one of claims 1-4, wherein the weight force compensator (200A) has a first adjustment element (236, 236') and a second adjustment element (238, 238'), and wherein the first adjustment element (236, 236') and the second adjustment element (238, 238') are spaced apart from each other along a central axis (202) of the weight force compensator (200A). [6] Optical system according to one of claims 1-5, wherein the passive magnetic circuit (228) is arranged inside the outer shell (208), and wherein the outer shell (208) is arranged inside the adjustment element (236, 236', 238, 238'). [7] Optical system according to one of claims 1-6, wherein the adjustment element (236, 236', 238, 238') is positively connected to the outer shell (208). [8] Projection exposure system (1) with an optical system (100) according to one of claims 1-7. [9] Method for adjusting the compensation force (K) of the weight force compensator (200A) of the optical system (100) according to any one of claims 1-8, comprising the steps: a) Releasing (S1) the clamping between the adjusting element (236, 236', 238, 238') and the outer shell (208) using an adjusting tool (260), b) Moving (S2) the adjusting element (236, 236', 238, 238') from an actual position (IP) to a target position (SP) using the adjusting tool (260), and c) Restore (S3) the clamping between the adjusting element (236, 236', 238, 238') and the outer shell (208) using the adjusting tool (260). [10] Method according to claim 9, wherein in step a) the adjusting element (236, 236', 238, 238') is deformed spring-elastically using the adjusting tool (260).

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