Optical device

Abstract

Optical device (24) comprising an optical element (25), a retaining frame (40), at least one spring (27, 29, 31) and at least one articulated connection (33, 34, 36), wherein the optical element (25) is clamped to the retaining frame (40) between the at least one spring (27, 29, 31) and the at least one articulated connection (33, 34, 36), with at least one spring adapter (28, 32) for contacting the spring (26, 29, 31) with the optical element (25) and with at least one articulated connection (33, 34, 36) for contacting the optical element (25) with the retaining frame (40).

Description

[0001] The present invention relates to an optical device. The invention further relates to an optical system comprising such an optical device and a projection exposure system comprising such an optical system.

[0002] Optical devices are known in projection exposure systems in various forms through prior use.

[0003] It is an object of the present invention to improve an optical device, in particular to make it particularly stable and durable.

[0004] This problem is solved according to the invention by an optical device having the features mentioned in claim 1.

[0005] The core of the invention lies in clamping an optical element to a support frame by means of at least one spring and at least one hinge connection. The optical element can, in particular, be in contact with the spring via the spring adapter. In this case, the optical element is not in contact with the spring. The spring adapter can be spatially arranged between the spring and the optical element.

[0006] With such an optical device, it is possible to clamp the optical element to the support structure in a particularly stable and material-friendly manner. The spring adapter can be designed in such a way as to compensate for any irregularities on the surface of the optical element and / or the spring.

[0007] This makes it possible, in particular, to transfer stresses, inhomogeneous pressure distributions, and / or other loads from the optical element and / or the spring to the spring adapter, so that such undesirable stresses, inhomogeneous pressure distributions, and / or loads do not act between the spring and the optical element. This can increase the service life of the optical element. The optical element is clamped to the mounting frame in a way that is gentle on the material. It has been found that the use of the spring adapter does not negatively affect the stability with which the optical element is held in the mounting frame. Therefore, by contacting the optical element with the spring via the spring adapter, a simultaneously stable and material-friendly clamping of the optical element to the mounting frame can be achieved.

[0008] Furthermore, the articulated connection for contacting the optical element with the mounting frame is advantageous. The optical device can be designed such that the optical element does not make direct contact with the mounting frame at any point. In this context, the at least one articulated connection can fulfill a similar function to the spring adapters. The at least one articulated connection can therefore also contribute to the stable and material-friendly clamping of the optical element to the mounting frame.

[0009] It is particularly possible that the optical device is a mirror device. It is especially possible that the optical element is designed as a mirror.

[0010] It is particularly possible that the optical device forms part of a projection exposure system, especially a lithography projection exposure system, which can be used for the production of micro- or nanostructured components. It is particularly possible that the lithography projection exposure system is an EUV projection exposure system, meaning that the useful light has a wavelength in the range between 5 nm and 30 nm, particularly 13.5 nm. It is also possible that the lithography projection exposure system is a DUV exposure system, meaning that it uses useful light with wavelengths in the range of 157 nm to 365 nm, particularly 193 nm.

[0011] The joint connection can be made of a hard plastic. It is also possible that the joint connection is made of a soft plastic.

[0012] The joint connection can, in particular, include a connecting body for connecting the joint connection to the mounting frame. The connecting body can have at least one stop surface with which it can rest against the mounting frame. The joint connection can be fastened to the mounting frame using the connecting body. Fasteners such as screws or bolts can be used for this purpose.

[0013] The joint connection can include a support body for the optical element. The support body can have a flat contact surface that serves to make contact between the joint connection and the optical element.

[0014] The connecting body and the support body can be designed as a single component. Alternatively, they can be designed as separate components and subsequently fastened together. In particular, it is possible for at least one contact surface of the connecting body to be oriented perpendicular to the contact surface of the support body. This allows, in particular, for the optical element and the mounting frame to contact each other via a 90° angle.

[0015] The spring can be made, at least partially, of metal. Stainless steel is a suitable metal for this purpose. The spring adapter can also be made of metal or at least include a metallic component. The spring adapter can also be made of stainless steel.

[0016] The optical element can have its greatest extent along a longitudinal direction, hereinafter referred to as the "longitudinal direction". Along another depth direction perpendicular to the longitudinal direction, hereinafter referred to as the "depth direction", the optical element can have its smallest extent. Along a transverse direction, hereinafter referred to as the "transverse direction", which can be perpendicular to both the longitudinal and depth directions, the optical element can have an extent that is, in particular, smaller than its longitudinal extent but larger than its depth direction. The optical element can, in particular, be designed as a cuboid. It can also be designed as a parallelepiped. The optical element can include a reflective surface.The reflective surface can extend, in particular, along the longitudinal and lateral directions.

[0017] Along the depth direction, a substrate thickness of the optical element on which the reflective surface is applied extends.

[0018] The mounting frame can be made of plastic or metal. The mounting frame can enclose the optical element, particularly on several sides. It is also possible for the mounting frame to be located on only one side of the optical element. The mounting frame allows the optical device to be integrated into higher-level optical systems.

[0019] An optical device according to claim 2 ensures a uniform transmission of a spring clamping force. A spring adapter can be arranged between each of the springs and the optical element. The optical device with the multiple springs can have exactly one joint connection or a plurality of joint connections. In particular, each spring can be assigned exactly one joint connection. Depending on the design of the optical device, the spring clamping force of the springs is transmitted uniformly to the spring adapters and / or the joint connections. Furthermore, the stability of the optical device, especially the local stability of individual areas of the optical device, can be increased by using a plurality of joint connections and / or spring adapters.It is particularly possible that the optical device has at least two springs and / or joint connections, in particular at least three springs and / or joint connections, in particular at least four springs and / or joint connections, in particular at least five springs and / or joint connections and in particular at least six springs and / or joint connections.

[0020] A wide variety of spring and / or joint configurations are possible on the optical element. If the number of joints used is equal to the number of springs, the spring and joint act as opposing forces, generating a clamping force that is essentially parallel to one of the main directions of the optical element.

[0021] It is also possible to use a different number of springs and joint connections. In such a case, the way the clamping force is applied through the optical element, the spring adapters, and the joint connection can be specifically controlled. In this way, stabilizing and / or material-protecting effects can be locally controlled.

[0022] For example, the reflective surface of the optical element may be contacted by three hinge connections. Two of these hinge connections can be arranged along an edge extending in the width direction. The third hinge connection can be arranged on the opposite edge.

[0023] A particularly uniform distribution of the clamping force is achieved when the three joint connections are arranged along the edges of the reflective surface at a constant distance from the geometric centroid of the reflective surface and at a relative phase of 120° to each other.

[0024] It is possible that three springs, each also on the side of the optical element opposite the reflective surface, are arranged in such a way that they act as counterparts to the joint connections, i.e., that the clamping force between a spring-joint connection pair runs essentially parallel to the depth direction.

[0025] It is also possible, in particular, that the reflective surface of the optical element is contacted by the three springs, and the side of the optical element opposite the reflective surface is contacted by the three hinge connections.

[0026] It is also possible to arrange two springs and two associated hinges along the longitudinal direction, which together generate a clamping force in the lateral direction. For example, both springs can be positioned on one side of the optical element perpendicular to the lateral direction, while the corresponding hinges are located on the opposite side. The springs and / or the hinges can also be positioned near the corners of the optical element.

[0027] It is possible that these spring-joint connection pairs are also arranged in such a way that the resulting clamping force runs essentially parallel to the width direction.

[0028] Alternatively, a spring and a hinge connection can be arranged on a side surface of the optical element that is perpendicular to its width. In such a case, the corresponding opposing elements for the spring and the hinge connection are arranged on the opposite side.

[0029] It is also possible to arrange a spring on a surface perpendicular to the longitudinal direction of the base body and a hinge connection on the opposite surface of the optical element to generate a clamping force in the longitudinal direction.

[0030] It is particularly possible that the spring is arranged in the area of ​​the geometric centroid of the surface perpendicular to the longitudinal direction.

[0031] It is possible that these spring-joint connection pairs are also arranged in such a way that the resulting clamping force runs essentially parallel to the longitudinal direction.

[0032] An optical device according to claim 3 can be designed to be particularly space-saving and flexibly adapted to the available installation space. However, depending on the requirements of the optical system in which the optical device is to be used, certain structural requirements exist for the mounting frame, particularly with regard to installation space. By designing the spring, for example, as a compression spring, coil spring, or tension spring, an optical device can be adapted to the respective conditions.

[0033] An optical device according to claim 4 can be implemented particularly efficiently. By designing the spring adapter as a spring shoe or as a pressure plunger, the spring adapter can be attached to the spring particularly quickly, efficiently, and easily. This saves working time and production costs.

[0034] An optical device according to claim 5 is particularly stable and gentle on materials. The flat contact surfaces with which the spring adapter connects to the optical element ensure that forces are transmitted to the spring adapter with exceptional uniformity. This allows for a particularly robust clamping of the optical element to the mounting frame. Furthermore, the exceptionally homogeneous force distribution between the optical element and the spring adapter can also increase the service life of the optical element, as potential mechanical stresses due to local force differences can be avoided and, in particular, eliminated.

[0035] An optical device according to claim 6 results in a particularly flexible optical device. If the optical element can be displaced by at least one translational degree of freedom and / or at least one rotational degree of freedom by using the spring adapters, not only can the distribution of the clamping force be controlled more precisely, but it is also possible to align the reflective surface of the optical element in the optical device according to the current requirements for the optical device.

[0036] In order to be able to move the optical element along at least one translational degree of freedom and / or at least one rotational degree of freedom, the spring adapters can be movably connected to the respective springs, and in particular, be freely rotatable.

[0037] An optical device according to claim 7 is also particularly versatile. For the flexibility of the optical device's application possibilities and the control of the clamping force distribution, it is irrelevant whether the optical element can be displaced by at least one translational degree of freedom and / or at least one rotational degree of freedom by means of the spring adapters or by means of the joint connections.

[0038] The joint connections can be designed, in particular, as solid-state joints and, especially, as solid-state universal joints. The design of the joint connections as universal joints can be achieved, in particular, by using two soft webs. These can be incorporated into the joint connection during manufacturing, for example, by cutting or milling.

[0039] An optical device according to claim 8 is particularly easy to machine. It has been shown in particular that brittle materials, especially due to their good microstructure homogeneity, can be polished and / or coated with particular efficiency.

[0040] Advantageously, the optical element is made, at least partially, of silicon, and in particular of silicon-infiltrated silicon carbide (SiSiC). Such materials possess particularly advantageous thermal properties. In particular, the coefficient of thermal expansion of such materials is especially low.

[0041] It is also possible that it is coated with a highly reflective coating in the EUV radiation range. Molybdenum or ruthenium, for example, would be suitable coating materials.

[0042] An optical device according to claim 9 is particularly durable. By applying a surface pressure of at most 10 MPa, in particular at most 9 MPa, in particular at most 8 MPa, in particular at most 7 MPa, in particular at most 6 MPa and in particular at most 5 MPa, it can be ensured that the optical element is not damaged and / or breaks along predetermined breaking points, such as solid defects.

[0043] Another object of the invention is to provide an improved optical system with at least one optical element.

[0044] This problem is solved according to the invention by an optical system having the features listed in claim 10.

[0045] The advantages of such an optical system correspond to those already explained with reference to the optical device according to claims 1 to 9.

[0046] An optical system according to claim 11 is particularly versatile. If the optical system itself includes a light source, it can not only process but also generate the light radiation. Such an optical system can be integrated into higher-level systems. In particular, it is not necessary to supply the optical system with external light radiation.

[0047] Another objective of the invention is to provide an improved projection exposure system.

[0048] This problem is solved according to the invention by a projection exposure system with the features listed in claim 12.

[0049] The advantages of such a projection exposure system correspond to those already explained with reference to the optical device and the optical system according to claims 1 to 11. The projection exposure system can, in particular, be a lithography projection exposure system for the production of micro- or nanostructured components. These components can be semiconductor components, especially microchips, for example, memory chips. The projection exposure system can use EUV light with a wavelength in the range between 5 nm and 30 nm, particularly 13.5 nm, or DUV light in the range between 157 nm and 365 nm, for example 193 nm, as the useful light source, i.e., as illumination and / or imaging light.

[0050] At least one embodiment of the invention is described below with reference to the drawing. The drawing shows: Fig. 1 schematically in meridional section a projection exposure system for EUV projection lithography; Fig. 2 a perspective view of the optical device with springs and solid joints; Fig. 3 compared to the Fig. 2 Perspective views of the optical device rotated by 180°; Fig. 4A to C in representation of the interaction of spring and joint device in longitudinal direction (A), lateral direction (B) and depth direction (C); Fig. 5 in sectional view a section of an optical device with solid joints in the width and depth directions; Fig. 6A, B in enlarged view a perspective representation of solid body joints in width direction (A) and depth direction (B); Fig. 7 in enlarged view a leaf spring with a spring adapter and Fig. Figure 8 shows a section of the optical device in a sectional view, in which the connection of the optical element to the retaining frame via the spiral spring can be seen.

[0051] The following will first refer to the Fig. 1. The essential components of a projection exposure system 1 for microlithography are described as an example. The description of the basic structure of the projection exposure system 1 and its components is not to be understood as restrictive.

[0052] A lighting system 2 of the projection exposure system 1 has, in addition to a radiation source 3, a lighting optic 4 for illuminating an object field 5 in an object plane 6. 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 moved, particularly in a scanning direction, by means of a reticle displacement drive 9.

[0053] In the Fig. Figure 1 shows a Cartesian xyz coordinate system for illustrative purposes. The x-direction runs perpendicular to the plane of the drawing. The y-direction runs horizontally, and the z-direction runs vertically.

[0054] The scan direction runs in the Fig. 1 along the y-direction. The z-direction runs perpendicular to the object plane. 6.

[0055] 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.

[0056] 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, 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.

[0057] Radiation source 3 is an EUV radiation source. Specifically, radiation source 3 emits EUV radiation 16, which is also referred to as useful radiation or illumination radiation. The useful radiation has a wavelength in the range between 5 nm and 30 nm. Radiation source 3 can be a plasma source, for example, an LPP (Laser Produced Plasma) source or a DPP (Gas Discharged Produced Plasma) source. It can also be a synchrotron-based radiation source. Radiation source 3 can be a free-electron laser (FEL).

[0058] The illumination radiation 16 emanating from the radiation 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.

[0059] 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 radiation source 3 and the collector 17, and the illumination optics 4.

[0060] The illumination optics 4 comprise a first faceted mirror 19. If the first faceted mirror 19 is arranged in a plane of the illumination optics 4 that is optically conjugate to the object plane 6, it is also referred to as a field faceted mirror. The first faceted mirror 19 comprises a plurality of individual first facets 20, which are also referred to as field facets in the following. Of these facets, in the Fig. 1 only some examples are shown.

[0061] The first facets 20 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or semicircular border contour. The first facets 20 can be designed as planar facets or alternatively as convexly or concavely curved facets.

[0062] As is known, for example, from DE 10 2008 009 600 A1, the first facets 20 themselves can each be composed of a plurality of individual mirrors, in particular a plurality of micromirrors. The first facet mirror 19 can in particular be designed as a microelectromechanical system (MEMS system). For details, reference is made to DE 10 2008 009 600 A1.

[0063] In the beam path of the illumination optics 4, a second faceted mirror 21 is arranged downstream of the first faceted mirror 19. If the second faceted mirror 21 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 21 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 19 and the second faceted mirror 21 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.

[0064] The second facet mirror 21 comprises a plurality of second facets 22. The second facets 22 are also referred to as pupil facets in the case of a pupil facet mirror.

[0065] The second facets 22 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.

[0066] The second facets 22 can have planar or alternatively convex or concave curved reflective surfaces.

[0067] The lighting optics 4 thus form a double-faceted system. This basic principle is also known as a fly's eye integrator or honeycomb condenser.

[0068] It can be advantageous not to arrange the second faceted mirror 21 exactly in a plane that is optically conjugate to a pupil plane of the projection optics 7. In particular, the pupil faceted mirror 21 can be arranged rotated relative to a pupil plane of the projection optics 10, as described, for example, in DE 10 2017 220 586 A1.

[0069] With the help of the second faceted mirror 21 and an imaging optical assembly in the form of a transmission optic 23, the individual first facets 20 are imaged into the object field 5.

[0070] The transmission optics 23 can be used as in the case of the version according to Fig. 1, 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 optics 23 can, in particular, comprise one or two mirrors for normal incidence (NI mirrors) and / or one or two mirrors for grazing incidence (GI mirrors). The illumination optics 4, in the embodiment described in the Fig. As shown in Figure 1, there are exactly three mirrors after the collector 17, namely the first faceted mirror 19, the pupil faceted mirror 21 and the mirror of the transmission optics 23.

[0071] In a further embodiment of the illumination optics 4, the transmission optics 15 can also be omitted, so that the second faceted mirror 21 is the last beam-shaping or indeed the last mirror for the illumination radiation 16 in the beam path before the object field 5. An example of an illumination optics 4 without transmission optics is disclosed in the Fig. 2 of the WO 2019 / 096654 A1.

[0072] The mapping of the first facets 20 by means of the second facets 22 or with the second facets 22 and a transmission optic 23 into the object plane 6 is regularly only an approximate mapping.

[0073] 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.

[0074] In the Fig. In the example shown, the projection optics 10 comprise eight mirrors M1 to M8. Alternatives with four, six, ten, twelve, or any other number of mirrors Mi are also possible. The last mirror M8 has a passage aperture for the illumination radiation 16. The projection optics 10 is an obscured optic. The projection optics 10 has an image-side numerical aperture that is less than 0.75, in particular less than 0.5, and in particular less than 0.3. The image-side numerical aperture of such a projection optics 10 is regularly greater than 0.1.

[0075] 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.

[0076] The mirrors Mi can in particular be designed as mirror devices, which are described below with reference to the Fig. 2 to 8 will be explained in more detail.

[0077] The projection optics 10 can be, in particular, anamorphic. They exhibit, in particular, different magnification ratios β. x , β yin the x and y directions. The two image scales β x , β y of the projection optics 10 are preferably located at (β x , β y ) = (+ / - 0.25, + / - 0.125). A positive magnification β indicates a transformation without image inversion. A negative magnification β indicates a transformation with image inversion.

[0078] The projection optics 10 lead to a reduction in the x-direction, that is, in the direction perpendicular to the scan direction, in a ratio of 4:1.

[0079] The projection optics 10 lead to a reduction of 8:1 in the y-direction, that is, in the scan direction.

[0080] Other magnification ratios are also possible. Magnification ratios with the same sign and absolute values ​​in the x and y directions, for example with absolute values ​​of 0.125 or 0.25, are also possible.

[0081] The number of intermediate image planes in the x- and y-directions 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 are known from US 2018 / 0074303 A1.

[0082] Each of the pupil facets 22 is assigned to exactly one of the field facets 20 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 by means of the field facets 20. The field facets 20 generate a plurality of images of the intermediate focus on the pupil facets 22 assigned to each of them.

[0083] The field facets 20 are each superimposed on the reticulum 7 by an associated pupil facet 22 to illuminate the object field 5. 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.

[0084] The illumination of the entrance pupil of the projection optics 10 can be geometrically defined by the arrangement of the pupil facets. By selecting the illumination channels, in particular the subset of pupil facets 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.

[0085] 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.

[0086] 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.

[0087] The projection optics 10 can, in particular, have a homocentric entrance pupil. This can be accessible. It can also be inaccessible.

[0088] The entrance pupil of the projection optics 10 cannot always be illuminated exactly by the pupil facet mirror 21. When the projection optics 10 image the center of the pupil facet mirror 21 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.

[0089] 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 23, should be provided between the second faceted mirror 21 and the reticle 7. This optical element can accommodate the different positions of the tangential and sagittal entrance pupils.

[0090] During the Fig. In the arrangement of the components of the illumination optics 4 shown in Figure 1, the pupil facet mirror 21 is not arranged in a plane conjugate to the entrance pupil of the projection optics 10. It is also tilted relative to the object plane 5. The second facet mirror 21 is further tilted relative to an arrangement plane defined by the first facet mirror 19.

[0091] Fig. Figure 2 shows a perspective view of an optical device 24, which can be used as part of the optical system of the projection exposure system 1 within the illumination optics 4 and / or within the projection optics 10. The optical device 24 comprises an optical element 25 with a reflective surface 26. Not shown in the Fig. Figure 2 shows the mounting frame to which the optical element 25 rests by means of springs and solid-state joints. This mounting frame is further described with reference to the Fig. 4A to C explained.

[0092] To better illustrate, the Fig. 2 ff. a Cartesian coordinate system. The longitudinal direction corresponds to the x-direction of the coordinate system, the latitude direction corresponds to the y-direction of the coordinate system, and the depth direction corresponds to the z-direction of the coordinate system.

[0093] Along the lateral direction y, the optical element 25 has three leaf springs 27. The leaf springs 27 serve to generate a clamping force that acts along the z-direction. Accordingly, the leaf springs 27 are also referred to as z-leaf springs 27.

[0094] The z-leaf springs 27 are each contacted with the reflective surface 26 at an edge extending in the lateral direction y by means of a spring adapter 28. Two z-leaf springs 27 with their respective spring adapters 28 extend in the lateral direction along one of the edges, while one z-leaf spring 27 is arranged at the opposite edge of the reflective surface 26.

[0095] On the side of the optical element 25 on which a z-leaf spring 27 is arranged, it is arranged centrally along the edge of the reflection surface 26.

[0096] It is also possible that the side surface of the optical element 25 opposite the reflective surface 26 is contacted by the three z-leaf springs 27. The arrangement of the z-leaf springs 27 on the side opposite the reflective surface 26 of the optical element 25 can be identical to the arrangement of the z-leaf springs 27 according to the illustration in Fig. 2 be.

[0097] The optical element 25 further comprises leaf springs 29, which serve to generate a clamping force in the lateral direction y. Accordingly, said leaf springs 29 are also referred to as y-leaf springs.

[0098] The y-leaf springs 29 are attached to a surface of the optical element 25 perpendicular to the width direction by means of a not in the Fig. The optical element 25 is contacted by spring adapters 28 shown in the illustration. Along the longitudinal direction, the optical element 25 comprises two y-leaf springs 29.

[0099] The y-leaf springs 29 have at least one stop surface 30 with which the y-leaf springs 29 contact the support structure. The stop surfaces 30 are in particular part of the y-leaf springs 29.

[0100] The optical element 25 further comprises a coil spring 31. The coil spring 31 serves to generate a clamping force in the longitudinal direction x. The coil spring 31 is contacted with a side surface of the optical element 25 perpendicular to the longitudinal direction x by means of a plunger adapter 32. Both the plunger adapter 32 and the spring adapters 28 each have a flat contact surface via which the respective spring 27, 29, 31 are contacted with the optical element 25.

[0101] As counterparts to the z-leaf springs 27, solid-state joints 33 are arranged on the side of the optical element 25 opposite the reflective surface 26 such that the solid-state joints 33, in conjunction with the leaf springs 27, generate a clamping force that runs essentially parallel to the depth direction z of the base body. The solid-state joints 33 serve to contact the optical element 25 with the mounting frames.

[0102] It is also possible that the solid joints 33 contact the reflective surface 26 of the optical element 25. In such a case, the arrangement of the solid joints 33 on the reflective surface 26 can be as shown in Fig. 2 shown, correspond.

[0103] The optical device 24 also has solid-state joints 34 which, in conjunction with the y-leaf springs 29, exert a clamping force on the optical element 25 that runs essentially parallel to the lateral direction y. The solid-state joints 34 have a lateral stop surface 35 with which the solid-state joints 34 bear against the mounting frame.

[0104] The optical device 24 further comprises a solid-state joint 36, which, in conjunction with the leaf spring 31, generates a clamping force that is essentially parallel to the longitudinal direction x. The solid-state joint 36 can, in particular, be identical in construction to the solid-state joint 33.

[0105] In addition to contacting the mounting frame, the solid-state joints 33, 34, 36 also fulfill the function of making the optical device 24 tiltable in at least one translational degree of freedom and / or at least one rotational degree of freedom, which will be described later with reference to the Fig. Sections 6A to B will be explained in more detail.

[0106] The optical device 24 according to Fig. 3 corresponds to the optical device 24 according to Fig. 2. The optical device 24 was compared to the illustration according to Fig. 2 rotated 180° around the latitude direction y.

[0107] Fig. Figure 3 shows that the contact surfaces 37 of the solid joints 33 are also planar and serve to contact the solid joints 33 with the supporting structure.

[0108] Furthermore, in Fig. Figure 2 also shows the stop surface 38, with which the solid joint 36 is contacted on the support structure. Stop 38 is also planar.

[0109] In addition to the lateral stop surfaces 35, the solid joints 34 have lower stop surfaces 39, which serve to provide additional contact between the solid joints 34 and the retaining frames.

[0110] The Fig. Figures 4A to 4C each show a sectional view of the optical device 24, illustrating how the individual stop surfaces 37, 38, 39 are contacted with the retaining frames 40.

[0111] Fig. Figure 4A shows the contact between the coil spring 31 and the associated solid-state joint 36 with the support structure 40. The coil spring 31 is wedged into a receptacle in the support structure 40. The solid-state joint 36 is in contact with the support structure 40 over its entire surface with its stop surface 38. A fastener, not shown in the Fig. 4A shows a fastening element. Screws, for example, can be used as fastening elements.

[0112] Fig. Figure 4B shows how the solid joint 34 and the y-leaf springs 29 are contacted with the support structure 40. In this context, the Fig. Figure 4B shows how the stop surface 39 is in contact with the support structure 40 over a flat area. The flat contact of the stop surface 35 with the support structure 40 is not shown in the Fig. Figure 4B shows the y-leaf spring 29 being contacted with the support structure 40 via the stop surface 30.

[0113] In the Fig. Figure 4B also shows the y-leaf spring 29 with an associated spring adapter 28. The spring adapter 28 serves to contact the y-leaf springs 29 with the optical element 25. The spring adapter 28 can, in particular, be identical in construction to the spring adapter 28 with which the z-leaf spring 27 rests against the optical element 25.

[0114] In the Fig. Figure 4C shows that the z-leaf spring 27 is directly contacted with the retaining frame 40, while the associated solid joint 33 is contacted with the retaining frame 40 via the stop surface 37.

[0115] Fig. Figure 5 shows a section view of the optical device 24, in which both a solid body joint 33 and a solid body joint 34 are shown.

[0116] The solid-body joints 33, 34 are shown with additional fastening elements 41, which serve to attach the solid-body joints 41 to the mounting frame 40. The fastening elements 41 can be made of metal, in particular. The fastening elements 41 can be designed as screws or bolts.

[0117] The Fig. Figures 6A and B show solid body joints 33 and 34 respectively in enlarged view.

[0118] In the Fig. Figure 6A shows the solid joint 33, which serves as the counterpart to the z-leaf spring 27. The solid joint 33 has two universal joints 42, 43, each formed from two soft webs. The cavities adjoining the universal joints 42, 43 can be incorporated into the solid joint 33 during the manufacturing process. These cavities can, for example, be cut or milled.

[0119] By forming the solid-state joint 33 with two switch webs 42, 43, it is possible to displace the optical element 25 along at least one rotational degree of freedom and, in particular, at least two rotational degrees of freedom. The solid-state joint 33 therefore serves not only to contact the optical element 25 with the mounting frame 40, but also to flexibly move the optical element 25 along at least one rotational degree of freedom.

[0120] The solid-body joint 33 also has two receptacles 44, which are designed as through-holes in the solid-body joint 33. The receptacles 44 serve to receive the fastening elements 41, with which the solid-body joint 33 can be attached to the mounting frame 40.

[0121] Fig. Figure 6B shows a solid-state joint 34, which serves as the counterpart to the y-leaf spring 29. The solid-state joint 34 also has two universal joints 42, 43, each formed by two connecting webs. Thus, the solid-state joint 34 not only serves to contact the optical element 25 with the mounting frame 40, but also allows the optical element 25 to be displaced by at least one rotational degree of freedom and, in particular, by at least two rotational degrees of freedom.

[0122] The receptacles 44 for receiving the connecting elements 41 are designed as through openings in the solid body joint 34.

[0123] Fig. Figure 7 shows a z-leaf spring 27 with a spring adapter 28 attached to it. The z-leaf spring 27 has three continuous receptacles 46. Two of these three through-holes 46 are arranged at one end of the leaf spring at a small distance from each other and serve to receive fastening elements 41 in order to contact the z-leaf spring 27 with mounting frames 41.

[0124] The remaining through-opening 46 serves to accommodate the receiving bolt 47 of the spring adapter 28.

[0125] The receiving bolt 47 of the spring adapter 28 is arranged in the through-opening 46 such that the spring adapter 28 can rotate freely in all directions. In this way, the z-leaf spring 27 allows the optical element 25 to tilt by at least one rotational degree of freedom, in particular by at least two rotational degrees of freedom, and especially by at least three rotational degrees of freedom. The receiving bolt 47 in the through-opening 46 can be additionally secured with a [missing information - likely a reference to a specific component or element] not located in the [missing information - likely a specific location]. Fig. The retaining element shown in Figure 7, for example a retaining ring, is stabilized. The spring adapter 28 has a flat stop surface 45 with which the spring adapter 28 contacts the optical element 25.

[0126] The z-leaf spring 27 can be made of metal, especially stainless steel. It is also possible that the z-leaf spring 27 is made of a hard plastic.

[0127] The y-leaf spring 29 can be essentially identical in construction to the z-leaf spring, except for the additional stop surface 30.

[0128] Fig. Figure 8 shows an enlarged cross-sectional view of the spiral spring 31 arranged on the optical element 25. The optical element 25 is contacted with the spiral spring 31 via the plunger adapter 32. The plunger adapter 32 has, in particular, a flat contact surface with which the plunger adapter 32 rests against the optical element 25.

[0129] Furthermore, a pressure plunger 47 is incorporated into the spiral spring 31. The pressure plunger 48 can be made of metal and has an internal cavity 49 that serves to receive the plunger adapter 32. The plunger adapter 32 contacts the pressure plunger 47, in particular via flat contact surfaces.

[0130] The plunger 47 terminates in a clamping cover 50. The coil spring 31 is pre-tensioned via the clamping cover 50 and attached to the retaining frame 40 (not shown). The coil spring 31 and the plunger 48 are, at least partially, located within the retaining frame 40. The clamping cover 50 serves to wedge the coil spring 31 against the retaining frame 40. In this way, the coil spring 31 is not only clamped, i.e., held force-fit in the retaining frame 40, but is also positively connected to the retaining frame 40 via the clamping cover 50.

[0131] To fabricate a microstructured component, in particular a highly integrated semiconductor device, for example a memory chip, using the projection exposure system 1, the reticle 7 and the wafer 13 are first prepared. Subsequently, a structure on the reticle 7 is illuminated with the illumination optics 4 using the illumination light 16 and projected onto a photosensitive layer on the wafer 13 using the projection optics 10 of the projection exposure system 1.

[0132] By developing the light-sensitive layer, a microstructure is then created on the wafer 13, and from this the micro- or nanostructured component is produced.

[0133] The component produced can be a microchip, in particular a memory chip. 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 [0062, 0065] US 2006 / 0132747 A1

[0063] EP 1 614 008 B1

[0063] US 6,573,978

[0063] DE 10 2017 220 586 A1

[0068] WO 2019 / 096654 A1

[0071] US 2018 / 0074303 A1

[0081]

Claims

[1] Optical device (24), - with an optical element (25), - a holding frame (40), - with at least one spring (27, 29, 31) mounted on the support frame (40), - with at least one articulated connection (33, 34, 36) mounted on the support frame (40), - wherein the optical element (25) is clamped to the holding frame (40) between the at least one spring (27, 29, 31) and the at least one articulated connection (33, 34, 36), - with at least one spring adapter (28, 32) for contacting the spring (27, 29, 31) with the optical element (25). [2] Optical device (24) according to claim 1, characterized by that the optical element (25) is clamped to the holding frame (40) with at least two springs (27, 29, 31). [3] Optical device (24) according to one of the preceding claims, characterized bythat the at least one spring (27, 29, 31) is designed as a leaf spring (27, 29) or as a spiral spring (31). [4] Optical device (24) according to one of the preceding claims, characterized by that the at least one spring adapter (28, 32) is designed as a spring shoe (28) or as a pressure tappet (32). [5] Optical device (24) according to one of the preceding claims, characterized by that the spring adapter (28) has a flat support surface (45). [6] Optical device (24) according to one of the preceding claims, characterized by that the spring adapter (28, 32) is designed such that the optical element (25) can be displaced by at least one rotational degree of freedom and / or at least one translational degree of freedom. [7] Optical device (24) according to one of the preceding claims, characterized bythat the articulated connection (33, 34, 36) is designed such that the optical element (25) can be displaced by at least one translational degree of freedom and / or at least one rotational degree of freedom. [8] Optical device (24) according to one of the preceding claims, characterized by that the optical element (25) is at least partially formed from a brittle material. [9] Optical device (24) according to one of the preceding claims, characterized by that the surface pressure acting on the optical element (25) is at most 10 MPa. [10] Optical system (2, 10) comprising at least one optical device (24) according to one of claims 1 to 9. [11] Optical system (2, 10) according to claim 10, characterized by a light source (3) for generating illuminating radiation (16). [12] Projection exposure apparatus (1) with an optical system (2, 10) according to claim 11.

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