OPTICAL SYSTEM AND PROJECTIONAL LIGHTING SYSTEM

Abstract

An optical system (100A, 100B, 100C) for a projection exposure system (1), comprising a first component (102) having at least one local first interface level (114), a second component (104) having at least one local second interface level (116), and a connecting device (122, 228, 364) for connecting the first component (102) to the second component (104), wherein the connecting device (122, 228, 364) secures the first component (102) and the second component (104) to each other in a direction of action (216, 218, 220, 222, 356, 358, 360, 362) oriented parallel to the first interface level (114) and / or parallel to the second interface level (116) by positive locking and / or friction locking.

Description

[0001] The present invention relates to an optical system for a projection exposure system and a projection exposure system with 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. Since most materials absorb light of this wavelength, such EUV lithography systems must employ reflective optics, i.e., mirrors, instead of the previously used refracting optics, i.e., lenses.

[0004] Such a projection system, in addition to the mirrors mentioned previously, includes a force frame to support the mirrors and a sensor frame that serves as a fixed reference for measuring the mirrors. This sensor frame can be composed of several components that are connected to form the sensor frame. Screw connections are used to join the components. However, due to external thermomechanical influences, undesirable displacements of the components perpendicular to the screw connections can occur. Since the components are normally connected by force through screw connections, there is no safeguard against lateral displacement. This is particularly relevant when the preload of the screw connections decreases due to settling or creep effects.

[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 a first component having at least one local first interface plane, a second component having at least one local second interface plane, and a connecting device for connecting the first component to the second component, wherein the connecting device secures the first component and the second component to each other in a direction of action oriented parallel to the first interface plane and / or parallel to the second interface plane by means of a positive locking and / or friction locking mechanism.

[0007] With the help of the additional connecting device, the positive locking and / or friction locking connection prevents the first component and the second component from shifting relative to each other in an undesirable way along the first interface level and / or along the second interface level.

[0008] The optical system is preferably a projection optic or part of a projection optic of the projection exposure system. Alternatively, the optical system can also be a lighting system or part of a lighting system of the projection exposure system. In the following, it is assumed that the optical system is part of a projection optic. In particular, the optical system is part of a projection optic in the form of a sensor frame. Therefore, the optical system can also be referred to as a sensor frame. In other words, the first component and the second component form a sensor frame.

[0009] The optical system can have any number of components. These components can be, for example, parts of a sensor frame, as mentioned previously. Besides the first and second components, such a sensor frame can have any number of additional components. Alternatively, the components can also be optical elements, especially lenses or mirrors. However, the components can also include any other parts of the optical system. The components can also include support structures or the like.

[0010] The first interface plane is formed or spanned, in particular, by a front face of the first component. Similarly, the second interface plane is formed or spanned by a front face of the second component. The front faces of the first component and the front faces of the second component are arranged facing each other. The first interface plane and the second interface plane are, in particular, parallel to each other and are preferably spaced apart. The connecting element is specifically arranged between the first interface plane or the front face of the first component and the second interface plane or the front face of the second component, whereby the interface planes can, however, be part of the connecting element.

[0011] In this context, an "interface plane" refers specifically to an area of ​​the respective component that is at least partially planar. If this area is not planar, but curved, for example, the interface plane contacts the area at a point or along a line. For instance, the interface plane can be a surface on the component against which the connecting element rests or which makes contact with the component. In other words, the interface planes can be formed by surfaces of the components. This means that the surface spans one of the interface planes, or that the interface plane is parallel to the surface. Therefore, the interface planes can be formed by surfaces of any shape on the components.As a purely exemplary example, the front sides of the components, which are particularly facing each other, could be considered here, as mentioned previously.

[0012] The fact that the first and second interface levels are each "local" means, in this case, that the respective interface level does not have to extend over the entire front surface of the respective component, which in this exceptional example could be plate-shaped, but only over a portion of the respective component. In particular, the respective interface level can only be located in an area of ​​the respective component where the connection device is also located. However, it is also possible for the interface levels to be global. "Global" in this context means an exceptional case in which the first interface level extends over the entire front surface of the first component, while the second interface level extends over the entire front surface of the second component.

[0013] Preferably, the optical system comprises several connection devices. Each individual connection device can be assigned a first interface level and a second interface level. In other words, each component can be assigned any number of interface levels. For example, the first component has several first interface levels, and the second component has several second interface levels. The first interface levels of the first component and / or the second interface levels of the second component can be oriented arbitrarily relative to each other, for example, tilted relative to each other. The interface levels can, for example, be formed as the surfaces of tensile profile bodies, which in this purely exemplary case constitute the components.

[0014] The first interface plane can be oriented arbitrarily in space relative to the first component. If the first component has a flat front surface to which the first interface is assigned, the first interface plane can be oriented arbitrarily to this front surface. "Arbitrary" includes parallel, oblique, or perpendicular to the front surface. In other words, the first interface plane is arranged in any orientation relative to the first component. The same applies to the second component and the second interface plane. The first and second interface planes are each arbitrarily arranged in space and arbitrarily oriented relative to each other. Therefore, the first and second interface planes can be arranged parallel, oblique, or perpendicular to each other.

[0015] The connecting device can be oriented arbitrarily in space relative to the interface planes. If multiple connecting devices are provided, they can be oriented arbitrarily in space and relative to each other. Each connecting device has its own direction of action. These directions of action can be arbitrary in space and relative to each other. The connecting devices are preferably located in the respective interface plane or are arranged parallel to the corresponding interface plane.

[0016] The connecting element can be located, in particular, in or parallel to a plane that is perpendicular to the respective interface plane. The connecting element then functions, for example, as a positive-locking and / or friction-locking connection between components, which in this special case are designed as bodies of revolution. In this case, the components preferably have conical contact surfaces or bearing surfaces. The interface planes can, in this case, bear against or contact such a bearing surface with a linear or point-like contact.

[0017] The connecting device can also function as a positive-locking and / or friction-locking connection between interface planes that are arranged with an angular offset relative to an axis of rotation. In this case, the first component and / or the second component can be rotationally symmetrical or at least partially rotationally symmetrical with respect to the respective axis of rotation. Multiple connecting devices can then be arranged distributed around the axis of rotation. In principle, the spatial arrangement of the interface planes is freely possible.

[0018] The connecting device fixes the first and second components to each other, particularly in the aforementioned direction of action. This means that any movement of the first and second components relative to each other along this direction of action is prevented or blocked. In other words, the connecting device prevents or blocks any movement of the first component relative to the second component, or vice versa, in the aforementioned direction of action.

[0019] Preferably, several connecting devices are provided to fix the first and second components together. Each connecting device is assigned a direction of action. These directions of action are oriented differently, so that the components are blocked against displacement in the different directions of action. For example, three or four connecting devices may be provided. The following discussion focuses on only one connecting device. This connecting device is arranged between the first and second components. The connecting device can make contact with both the first and second components.

[0020] A positive-locking connection is created by the interlocking or overlapping of at least two connecting partners. For this purpose, the respective connecting device has several components, which will be explained below, that interlock or overlap to create a positive-locking connection. A friction-locking or force-locking connection requires a normal force on the surfaces to be joined. Mutual displacement of these surfaces is prevented as long as a counterforce caused by static friction is not exceeded. To create such a friction-locking or force-locking connection, components of the respective connecting device are pressed against each other to generate the normal force mentioned above.

[0021] The first and second components can each have any geometry. In the simplest case, the first and second components are at least partially plate-shaped or cuboid-shaped. The components can be placed on top of or next to each other. The components can also be placed inside one another. For example, the first component is cylindrical, while the second component is tubular. In this case, the first component can be arranged inside the second component, with several connecting elements placed between the first and second components. The components can also each have a polygonal cross-sectional geometry, for example, a hexagonal geometry.

[0022] Preferably, the optical system has at least one connection device per local interface, particularly with corresponding local interface levels. This means that any number of local interfaces, each of which can have at least one connection device, can be provided.

[0023] According to one embodiment, the optical system has several connecting devices, each connecting device being assigned a direction of action, and the directions of action being at least partially oriented differently.

[0024] The optical system preferably comprises exactly four connecting devices. The connecting devices are spaced apart from one another, and their directions of action are preferably oriented such that they point away from each other. For example, at least two directions of action can always be parallel to each other and oriented in opposite directions. With the aid of the at least three connecting devices, a statically determinate positioning of the first component and the second component relative to each other is possible. The directions of action of the connecting devices are configured such that they enable a complete positive locking of the degrees of freedom of the entire connection between the two components.

[0025] According to a further embodiment, the first component and the second component are connected to each other at at least one connection point by means of a positive locking connection, wherein the positive locking connection acts perpendicular to the first interface plane and perpendicular to the second interface plane.

[0026] At the connection points, the first component rests against the second component. Preferably, screw connections are provided at these connection points so that the first component can be screwed to the second component. In particular, each connection point is associated with a connection device as described above. The screw connection between the first component and the second component creates a positive-locking connection along the screw connection and a force-locking connection perpendicular to the screw connection, and thus also perpendicular to the first and second interface planes.

[0027] According to a further embodiment, the connecting device has a first contact web which is fixedly connected to the first component and a second contact web which is fixedly connected to the second component, wherein the connecting device has a connecting unit which is arranged between the first contact web and the second contact web.

[0028] The first contact web is preferably formed integrally with the first component, particularly as a single piece of material. Similarly, the second contact web is preferably formed integrally with the second component, particularly as a single piece of material. The connecting unit differs from the connecting device in that the contact webs are part of the connecting device but not of the connecting unit. The connecting unit is arranged, in particular, both between the first and second contact webs and between the first and second interface levels.

[0029] According to another embodiment, the connecting unit is subjected to a preload force by means of a fastening element between the first contact web and the second contact web.

[0030] This increases the rigidity of the connection. This means that gaps or incomplete contact surfaces, for example due to unevenness, manufacturing tolerances, roughness, or the like, are reduced by the preload of the fastener. This results in improved rigidity and force transmission. The fastener can be, for example, a screw. Several such fasteners can be used. The fastener can, for example, pass through openings provided in the first and second contact webs. Furthermore, it is also possible to pass the fastener or multiple fasteners directly through the connection unit.

[0031] According to another embodiment, the first support rib and the second support rib are oriented obliquely to each other.

[0032] In this case, the first and second contact surfaces are preferably straight. The inclined arrangement allows for a wedge angle, particularly a variable one, of the respective connecting element. The first contact surface has a contact surface, and the second contact surface also has a contact surface. The contact surfaces of the first and second contact surfaces are oriented at an angle to each other. The connecting unit is arranged between the two contact surfaces. The inclined arrangement of the first and second contact surfaces results in a wedge-shaped geometry of the connecting element.

[0033] According to another embodiment, the first support rib and the second support rib are straight, curved in an arc, or V-shaped.

[0034] The first and second mounting platforms can therefore, in principle, have any geometry.

[0035] According to a further embodiment, the connecting unit has several lamellar first circumferential support elements, several lamellar second circumferential support elements and a support disc against which the first circumferential support elements and the second circumferential support elements bear circumferentially, wherein the support disc is arranged between the first circumferential support elements and the second circumferential support elements, wherein the first circumferential support elements and the second circumferential support elements are arranged between the first contact web and the second contact web, wherein the first circumferential support elements and the support disc are in particular formed in one piece, or wherein the second circumferential support elements and the support disc are in particular formed in one piece.

[0036] For example, the first circumferential support elements and the support disc can be formed in one piece or as a single unit. Alternatively, the second circumferential support elements and the support disc can be formed in one piece or as a single unit. The number of first circumferential support elements and the number of second circumferential support elements is arbitrary. For example, six first circumferential support elements and six second circumferential support elements are provided. The first circumferential support elements and the second circumferential support elements are each lamellar or sheet-shaped. Accordingly, a stack of first circumferential support elements is placed on top of each other. Accordingly, a stack of second circumferential support elements is also placed on top of each other. Preferably, several support discs are provided. Two support discs can be provided. The support discs and the circumferential support elements are placed between the first interface plane and the second interface plane.The first circumferential support elements have cutouts that are curved in an arc. Each cutout of the first circumferential support element has a contact surface that rests against an outer surface of the support disc. The same applies to the second circumferential support elements. The circumferential support elements thus engage the support disc in a form-fitting manner.

[0037] According to another embodiment, the first circumferential support elements and the second circumferential support elements are connected to the first component or to the second component by means of fastening elements.

[0038] Screws, for example, can be used as fasteners. The first and second circumferential support elements each have an opening through which a fastener can be inserted. The circumferential support elements are connected to either the first or the second component. Specifically, this means that the circumferential support elements are not connected to both the first and second components. The first or second component can have an elongated hole for each of the two circumferential support elements, through which the respective fastener is inserted.

[0039] According to another embodiment, the optical system has a support element that is arranged between the first support rib and the first circumferential support elements and / or between the second support rib and the second circumferential support elements.

[0040] The shim and the first circumferential support elements can be formed in one piece or as a single unit. Furthermore, it is also possible for the shim and the second circumferential support elements to be formed in one piece or as a single unit. Additionally, the first circumferential support elements, the support washer, and the shim can be formed in one piece or as a single unit. Alternatively, the second circumferential support elements, the support washer, and the shim can be formed in one piece or as a single unit. Preferably, each connecting device comprises at least exactly two shims. A first shim is arranged between the first contact rib and the first circumferential support elements, and a second shim is arranged between the second contact rib and the second circumferential support elements. The shims are disc-shaped or sheet-shaped.The shims can be used to compensate for unevenness of the first support rib, the second support rib, the first circumferential support elements and / or the second circumferential support elements.

[0041] According to another embodiment, the support element has relief cuts.

[0042] In this context, a "free cut" is understood to be a gap or cut that passes through the support element, at least partially. Preferably, the free cuts are arranged such that the support element has a meandering geometry when viewed from above. The deformability or stiffness of the support element can be influenced by means of the free cuts. Preferably, the connecting device comprises several such support elements with free cuts.

[0043] According to a further embodiment, the connecting unit has first comb elements and second comb elements, wherein the first comb elements are connected to the first mounting rib, wherein the second comb elements are connected to the second mounting rib, and wherein comb sections of the first comb elements and comb sections of the second comb elements interlock in a comb-like manner.

[0044] In other words, the comb sections of the first comb elements and the comb elements of the second comb elements are inserted into one another. Preferably, a first comb element and a second comb element always form a comb element assembly. Accordingly, each connecting device preferably has two such comb element assemblies. The comb elements are preferably screwed to their respective associated mounting ribs. A shim, as mentioned above, can be arranged between each comb element and its respective mounting rib.

[0045] According to a further embodiment, the connecting unit has exactly one first comb element and exactly one second comb element, wherein the first comb element is connected to the first support rib, wherein the second comb element is connected to the second support rib, and wherein comb sections of the first comb element and comb sections of the second comb element interlock in a comb-like manner.

[0046] In contrast to the previous explanation, this version does not provide for two first comb elements, but exactly one first comb element, and not two second comb elements, but exactly one second comb element. Each comb element preferably has two comb sections. The comb sections of the first comb element and the comb sections of the second comb element are interlocked.

[0047] According to another embodiment, the comb sections are each connected to each other by means of a fastening element in a force-fit manner.

[0048] The fastener can be a screw. Each comb section has an opening through which the fastener can be inserted. The comb sections are fitted together, with the fastener being inserted through the openings and then, for example, screwed in place to press the comb sections together, creating a force-fit or friction-fit connection between the comb elements. Alternatively or in addition to screwing, the comb sections can also be tightened, compressed, or clamped and / or pre-tensioned in another suitable manner.

[0049] Furthermore, a projection exposure system with such an optical system is proposed.

[0050] The optical system is preferably a projection optic or part of a projection optic of the projection exposure system. In particular, the optical system can be a sensor frame as mentioned above and thus part of a projection optic. However, the optical system can also be an illumination system or part of an illumination 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.

[0051] 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.

[0052] The embodiments and features described for the optical system apply accordingly to the proposed projection exposure system and vice versa.

[0053] 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.

[0054] 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 perspective view of an embodiment of an optical system for the projection exposure system according to Fig. 1; Fig. Figure 3 shows a schematic perspective view of an embodiment of a connecting device for the optical system according to Fig. 2; Fig. Figure 4 shows a schematic exploded view of the connection device according to Fig. 3; Fig. Figure 5 shows a schematic top view of an embodiment of a support element for the connecting device according to Fig. 3; Fig. Figure 6 shows a schematic top view of the optical system according to Fig. 2; Fig. Figure 7 shows a schematic view of another embodiment of an optical system for the projection exposure system according to Fig. 1; Fig. Figure 8 shows a schematic exploded view of an embodiment of a connecting device for the optical system according to Fig. 7; Fig. Figure 9 shows a schematic perspective view of an embodiment of a comb element arrangement for the connecting device according to Fig. 8; Fig. Figure 10 shows a schematic top view of the optical system according to Fig. 7; Fig. Figure 11 shows a schematic view of another embodiment of an optical system for the projection exposure system according to Fig. 1; and Fig. Figure 12 shows a schematic exploded view of an embodiment of a connecting device for the optical system according to Fig. 11.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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 illumination 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).

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] Between the collector 17 and the deflecting mirror 19, the illumination radiation 16 runs horizontally, i.e. along the y-direction y.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] The second facets 23 can have planar or alternatively convex or concave curved reflective surfaces.

[0072] 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).

[0073] 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.

[0074] 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.

[0075] 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, which are 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).

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] The projection optics 10 lead to a reduction of 8:1 in the y-direction y, that is, in the scan direction.

[0086] Other magnification ratios are also possible. Magnification ratios with the same sign and absolute value in the x and y directions (x, y), for example with absolute values ​​of 0.125 or 0.25, are also possible.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] The projection optics 10 can, in particular, have a homocentric entrance pupil. This can be accessible. It can also be inaccessible.

[0094] The entrance pupil of the projection optics 10 cannot be precisely illuminated 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.

[0095] 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.

[0096] 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.

[0097] Fig. Figure 2 shows a schematic perspective view of an embodiment of an optical system 100A.

[0098] The optical system 100A can be a projection optic 10 as mentioned above, or part of such a projection optic 10. Furthermore, the optical system 100A can also be an illumination system 2 as mentioned above, or part of such an illumination system 2. The optical system 100A comprises several optical elements, in particular mirrors, which are arranged in the Fig. However, 2 are not shown. The optical elements can be the previously mentioned mirrors M1 to M6.

[0099] The optical system 100A comprises a first component 102 and a second component 104. The first component 102 is in the Fig. 2 is shown transparently, so that the second component 104 is visible through the first component 102. The components 102 and 104 can be any parts of the optical system 100A. In this case, the components 102 and 104 are parts of a so-called sensor frame, which are connected to each other. Accordingly, the optical system 100A can thus be part of a projection optic 10 in the form of a sensor frame. The components 102 and 104 are in the Fig. 2 is shown in a highly simplified, plate-like form. In reality, components 102 and 104 each have a complex, block-like geometry. Components 102 and 104 are each made of a ceramic material.

[0100] The first component 102 has a front face 106 facing the second component 104 and a rear face 108 facing away from the front face 106. Similarly, the second component 104 has a front face 110 facing the first component 102 and a rear face 112 facing away from the front face 110. The front face 106 of the first component 102 forms a first interface level 114. The front face 110 of the second component 104 forms a second interface level 116. The interface levels 114 and 116 are parallel to each other and spaced apart.

[0101] The first component 102 has a first contact web 118 extending from the front face 106 towards the second component 104. The first contact web 118 is rod-shaped or web-shaped. The first contact web 118 is formed integrally, in particular integrally, with the first component 102. "Integrated" or "one-piece" means that the first component 102 and the first contact web 118 are not formed from separate sub-components, but rather form a single component, namely the first component 102. "Integrated" means that the first component 102 and the first contact web 118 are manufactured entirely from the same material. The first contact web 118 extends from the first interface plane 114 and projects towards the second interface plane 116. The first component 102 comprises several, for example four, such first contact webs 118.

[0102] The second component 104 includes a second contact web 120. The second contact web 120 extends from the front face 110 of the second component 104. The second contact web 120 extends from the second interface level 116 and projects towards the first interface level 114. The second contact web 120 is formed integrally, in particular integrally, with the second component 104. The second component 104 has several, for example four, second contact webs 120. The first contact web 118 and the second contact web 120 are oriented obliquely to each other.

[0103] The first mounting web 118 and the second mounting web 120 are part of a connecting device 122, by means of which the first component 102 is connected to the second component 104. The interface levels 114, 116 are also part of the connecting device 122. The connecting device 122 comprises a connecting unit 124, which is arranged between the first mounting web 118 and the second mounting web 120.

[0104] Fig. Figure 3 shows a schematic perspective view of an embodiment of a connecting device 122 as previously mentioned. Fig. Figure 4 shows a schematic exploded view of the connecting device 122. The following refers to the Fig. 2, Fig. 3 to Fig. 4 referenced simultaneously.

[0105] The connecting device 122 comprises the aforementioned connecting unit 124, which is arranged between the first mounting web 118 and the second mounting web 120. The first mounting web 118 has a mounting surface 126. Accordingly, the second mounting web 120 has a mounting surface 128. The mounting surfaces 126 and 128 are arranged facing each other. The mounting surfaces 126 and 128 are oriented obliquely to each other. The mounting surface 126 is oriented perpendicular to the first interface plane 114. The mounting surface 128 is oriented perpendicular to the second interface plane 116.

[0106] The connecting unit 124 is positioned between the contact surface 126 and the contact surface 128. The connecting unit 124 comprises several support discs 130. The support discs 130 are positioned between the interface planes 114 and 116. For example, two such support discs 130 are provided. The support discs 130 can be made of a ceramic or metallic material. For example, the support discs 130 can be made of alloys comprising tungsten or molybdenum or of a TZM alloy. Each support disc 130 has a central opening 132 and a cylindrical outer surface 134.

[0107] The support discs 130 are arranged between a plurality of first circumferential support elements 136 and a plurality of second circumferential support elements 138. For example, six such first circumferential support elements 136 and six second circumferential support elements 138 are provided. If two support discs 130 are provided, each support disc 130 is assigned exactly three first circumferential support elements 136 and exactly three second circumferential support elements 138. The support discs 130 are radially pressed between the circumferential support elements 136 and 138.

[0108] The first circumferential support elements 136 each have a cutout 140 with a contact surface 142. The cutout 140 can be curved in a circular arc. The contact surface 142 is accordingly cylindrical. The contact surfaces 142 of the first circumferential support elements 136 abut the outer surface 134 of the support discs 130. The first circumferential support elements 136 also each comprise a contact surface 144 facing the contact surface 126 of the first support web 118.

[0109] Furthermore, each first circumferential support element 136 includes an opening 146 through which a fastening element 148, for example in the form of a screw, is passed. The fastening element 148 is in an elongated hole 150 ( Fig. 1) included, which is incorporated into the second component 104. The first component 102 can also have such an elongated hole 150.

[0110] Each of the second circumferential support elements 138 comprises a cutout 152, which is curved in a circular arc. The respective cutout 152 has a partially cylindrical contact surface 154. The contact surface 154 faces the outer surface 134 of the support discs 130. In particular, the second circumferential support elements 138, with their contact surfaces 154, abut the outer surface 134 of the support discs 130. Furthermore, each second circumferential support element 138 comprises a contact surface 156, which faces the contact surface 128 of the second support web 120.

[0111] Furthermore, every second circumferential support element 138 includes an opening 158 through which a fastening element 160, for example in the form of a screw, is passed. The fastening element 160 is in an elongated hole 162 ( Fig. 1) included, which is incorporated into the second component 104. In particular, the first component 102 can also have such an elongated hole 162. The two elongated holes 150, 162 run obliquely to each other.

[0112] A support element 164 is arranged between the first support rib 118, in particular between the support surface 126 of the first support rib 118, and the first circumferential support elements 136, in particular the support surfaces 144 of the first circumferential support elements 136. The support element 164 comprises a support surface 166 facing the support surface 126 and a support surface 168 facing the support surfaces 144 of the first circumferential support elements 136.

[0113] Fig. Figure 5 shows a schematic top view of an embodiment of a support element 164 as mentioned above.

[0114] The support element 164 is plate-shaped. The support element 164 is pressed between the contact surfaces 126, 144. The support element 164 can have several relief cuts 170, 172. This results in the following in the top view according to the Fig. 5 a meandering geometry of the support element 164.

[0115] Now returning to the Fig. 2, Fig. 3 to Fig. 4 The connecting device 122 further comprises an additional support element 174, which may be identical in construction to the support element 164. The support element 174 comprises a contact surface 176 facing the contact surface 128 of the second contact web 120 and a contact surface 178 facing the contact surfaces 156 of the second circumferential support elements 138. The support element 174 is pressed between the contact surfaces 128 and 156. The support element 174 may also have cutouts 170 and 172, as previously described with reference to the support element 164.

[0116] As the Fig. As shown in Figure 3, the connecting device 122 comprises two fastening elements 180, 182, for example in the form of screws, with which the mounting webs 118, 120 can be pre-tensioned against each other in order to press the connecting unit 124 between the two mounting webs 118, 120. The fastening elements 180, 182 are passed through openings 184, 186, 188, 190 provided in the mounting webs 118, 120. Washers 192, 194, 196, 198 are arranged between the mounting webs 118, 120 and the fastening elements 180, 182, which can compensate for a heat-induced change in length of the fastening elements 180, 182. The mounting webs 118, 120 can be pre-tensioned against each other using the fastening elements 180, 182, as shown in the Fig. 3 is indicated by arrows 200, 202, 204, 206.

[0117] Fig. Figure 6 shows a highly schematic top view of the optical system 100A.

[0118] In the Fig. Figure 6 specifically shows only the second component 104 with the second interface level 116. The first component 102 is not shown in the Fig. Figure 6 shows only several, namely four, first mounting platforms 118. The second component 104 accordingly also comprises a plurality of second mounting platforms 120 as mentioned above. Each pair of mounting platforms 118, 120 is assigned a connecting device 122 as mentioned above. Each connecting device 122 comprises a connecting unit 124, which is located in the Fig. 6 are represented in a very simplified way as circles.

[0119] The two components 102, 104 are connected to each other at connection points 208, 210, 212, 214, for example by screws. At connection points 208, 210, 212, 214, the two components 102, 104 are positively connected to each other in a direction perpendicular to the interface planes 114, 116. A positive connection is created by the interlocking or overlapping of at least two connecting partners.

[0120] In a direction parallel to the interface planes 114, 116, a friction-fit or force-fit connection is realized at the connection points 208, 210, 212, 214. Force-fit connections require a normal force on the surfaces to be joined. Their mutual displacement is prevented as long as a counterforce caused by static friction is not exceeded. At the connection points 208, 210, 212, 214, both components 102, 104 are therefore in contact with each other.

[0121] With the aid of the connecting devices 122, components 102 and 104 can now be fixed to one another in each of the directions of action 216, 218, 220, 222 parallel to the interface planes 114, 116 by means of a positive-locking connection realized by the respective connecting devices 122. This prevents the components 102 and 104 from shifting relative to each other along the interface planes 114, 116. Thermal expansion of the connecting devices 122 can also occur along and opposite the directions of action 216, 218, 220, 222. Thus, one degree of freedom for thermal expansion is provided along and opposite the directions of action 216, 218, 220, 222.

[0122] With the aid of the connecting device 122, an adjustable or adaptive positive locking connection can be realized as a safeguard against lateral displacement of the components 102, 104 relative to each other. This is particularly useful as a supplement to the connection points 208, 210, 212, 214. The connecting device 122 also enables passive compensation of thermal expansion.

[0123] The connecting device 122 comprises the support discs 130, which can be made, for example, of a ceramic or a metal, and the several flat circumferential support elements 136, 138, of which, for example, three are provided per support disc 130. The circumferential support elements 136, 138 are connected to one of the components 102, 104 by means of screw connections comprising the fastening elements 148, 160 and the elongated holes 150, 162. The circumferential support elements 136, 138 are connected to each other simultaneously.

[0124] By appropriately positioning the screw connections of the circumferential support elements 136, 138, a specific direction of thermal expansion is achieved, namely, in particular, the respective direction of action 216, 218, 220, 222, which corresponds to a wedge angle of the contact webs 118, 120 and enables thermal expansion with minimal or even no additional mechanical stresses in the connection device 122. For this purpose, the shims 164, 174, which are made of a material with a low coefficient of thermal expansion (CTE), can be used. The shims 164, 174 are designed such that they can be geometrically adapted to unevenness of the contact surfaces 126, 128, 144, 156 by means of corresponding relief cutouts 170, 172.

[0125] The materials of the entire connecting device 122 can be specifically selected to have a similar CTE to the materials of the components 102, 104 to be joined. This also includes the materials of the circumferential support elements 136, 138 and the support washer 130. This targeted material selection makes it possible to achieve a thermally expansion-neutral connecting device 122 that minimizes or even completely avoids mechanical stresses due to temperature changes.

[0126] The support discs 130 have sufficient degrees of freedom to accommodate thermal expansion. The circumferential support elements 136, 138 have rounded contact surfaces 142, 154 in a contact area with the support discs 130 for more favorable force transmission in the event of misalignment and / or inclination. This is advantageous, for example, in the case of unevenness in the contact webs 118, 120.

[0127] To increase the stiffness of the connecting device 122, the contact webs 118, 120 are tightened and / or pre-tensioned by means of screw connections comprising the fastening elements 180, 182 and the washers 192, 194, 196, 198. This means that gaps or incomplete contact surfaces, for example due to unevenness, manufacturing tolerances, roughness, or the like, are reduced by pre-tensioning the fastening elements 180, 182. This results in improved stiffness and force transmission.

[0128] The fasteners 180, 182 are guided through the openings 184, 186, 188, 190 of the mounting ribs 118, 120. Optional washers 192, 194, 196, 198 can be located under the head and nut of each fastener 180, 182. The washers 192, 194, 196, 198 are made of a specific material or material combination that expands with increasing temperature, thus increasing the thickness of the washers 192, 194, 196, 198. This compensates for any loss of preload in the fasteners 180, 182.

[0129] The connecting device 122 thus enables an adaptive and / or adjustable positive-locking connection that functions both with deviations in the wedge angles of the contact webs 118, 120 and with unevenness of the contact surfaces 126, 128 of the contact webs 118, 120. The connecting device 122 also enables passive compensation of thermal expansion. For this purpose, components, such as the support discs 130 or the circumferential support elements 136, 138, should have corresponding degrees of freedom as well as suitable shapes and orientations for the connecting device 122 so that they can expand freely and without restrictions. The selection of suitable material combinations for the components, which achieve a coefficient of thermal expansion (CTE) that corresponds to that of ceramics, also contributes to this.

[0130] Fig. Figure 7 shows a schematic view of another embodiment of an optical system 100B.

[0131] All statements concerning optical system 100A are applicable to optical system 100B and vice versa. Optical system 100B comprises a first component 102, as previously mentioned, and a second component 104. Components 102 and 104 are assigned interface levels 114 and 116, as previously mentioned, which are described in the Fig. However, components 7 are not shown. Components 102 and 104 are also not shown. Fig. 7 only shown in excerpts.

[0132] The first component 102 comprises a first mounting platform 224, which, unlike the first mounting platform 118 of the optical system 100A, is not straight but V-shaped or curved. The second component 104 is associated with a second mounting platform 226, which is also not straight but V-shaped or curved. The mounting platforms 224 and 226 are part of a connecting device 228, which includes a connecting unit 230 arranged between the mounting platforms 224 and 226. The connecting device 228 differs structurally from the previously described connecting device 122 of the optical system 100A.

[0133] Fig. Figure 8 shows a schematic exploded view of an embodiment of a connecting device 228 as previously mentioned. The following refers to the Fig. 7 and Fig. 8 received simultaneously.

[0134] The first mounting web 224 comprises a V-shaped or arcuately curved mounting surface 232. Accordingly, the second mounting web 226 comprises a V-shaped or arcuately curved mounting surface 234. The mounting surfaces 232 and 234 face each other. The connecting unit 230 is arranged between the mounting surfaces 232 and 234.

[0135] The connecting unit 230 comprises a pair of first comb elements 236, 238. Each first comb element 236, 238 comprises a base section 240, 242 and a comb section 244, 246 extending from the respective base section 240, 242. The comb sections 244, 246 include openings 248, 250. The base sections 240, 242 further comprise contact surfaces 252, 254, which are arranged facing the contact surface 232 of the first contact web 224.

[0136] Furthermore, the connecting unit 230 also comprises a pair of second comb elements 256, 258. The second comb elements 256, 258 are engaged with the first comb elements 236, 238. Each second comb element 256, 258 comprises a plate-shaped base section 260, 262 and a comb section 264, 266 extending from the respective base section 260, 262. Each comb section 264, 266 includes an opening 268, 270. The openings 268, 268 of the comb elements 236, 256 are arranged coaxially with each other. Accordingly, the openings 250, 270 of the comb elements 238, 258 are also arranged coaxially with each other. The second comb elements 256, 258 comprise on their base sections 260, 262 mounting surfaces 272, 274, which are arranged facing the mounting surface 234 of the second mounting bridge 226.

[0137] Between the first comb elements 236, 238 and the contact surface 232 of the first contact rib 224, shims 276, 278 are arranged. Each shim 276, 278 comprises a contact surface 280, 282 facing the contact surface 232 and a contact surface 284, 286 facing away from the respective contact surface 280, 282. Accordingly, shims 288, 290 are also arranged between the second contact rib 226, in particular its contact surface 234, and the second comb elements 256, 258. The shims 288, 290 have contact surfaces 292, 294 facing the contact surface 234. Facing away from the contact surfaces 292, 294, the shims 288, 290 comprise contact surfaces 296, 298.

[0138] The support elements 276, 278 abut with their contact surfaces 280, 282 the contact surface 232 of the first support rib 224 and with their contact surfaces 284, 286 the contact surfaces 252, 254 of the first comb elements 236, 238. The support elements 288, 290 abut with their contact surfaces 292, 294 the contact surface 234 of the second support rib 226 and with their contact surfaces 296, 298 the contact surfaces 272, 274 of the second comb elements 256, 258. The support elements 276, 278, 288, 290 can have the previously described cutouts 170, 172 (not shown).

[0139] Fig. Figure 9 shows a schematic perspective view of an embodiment of a comb element arrangement 300 for the optical system 100B.

[0140] The connecting device 228 has two such comb element arrangements 300. The ones in the Fig. The comb element arrangement 300 shown in Figure 9 comprises comb elements 238 and 258. As shown in Figure 9, the comb element arrangement 300 comprises comb elements 238 and 258. Fig. As can be seen from Figure 9, the comb sections 246, 266 are designed such that they can be interlocked like a comb. A fastening element 302 passes through the openings 250, 270 of the comb sections 246, 266. The fastening element 302 can be a screw. The comb sections 246, 266 can be pressed together using the fastening element 302. The base sections 242, 262 of the comb elements 238, 258 include openings 304, 306.

[0141] Now returning to the Fig. 7. The comb elements 236, 238, 256, 258 are connected to the components 102, 104, in particular to the contact webs 224, 226, by means of fastening elements 308, 310, 312, 314 passing through the openings 304, 306. In particular, the first comb elements 236, 238 are connected to the first contact web 224 of the first component 102 by means of the fastening elements 308, 310. Accordingly, the second comb elements 256, 258 are connected to the second contact web 226 of the second component 104 by means of the fastening elements 312, 314. The respective comb sections 244, 264 of the comb elements 236, 256 and the comb sections 246, 266 of the comb elements 238, 258 are each pressed together using a fastening element 302 (not shown) as mentioned above.

[0142] The connecting device 228 further comprises fastening elements 316, 318, by means of which the mounting webs 224, 226 can be pre-tensioned against each other. For this purpose, openings 320, 322, 324, 326 are provided in the mounting webs 224, 226, through which the fastening elements 316, 318 are passed. Washers 328, 330, 332, 334 can be arranged on the fastening elements 316, 318, which can compensate for thermal expansion of the fastening elements 316, 318.

[0143] The washers 328, 330, 332, 334 each rest against a suitable geometry 336, 338 of the respective contact rib 224, 226. The tension of the two contact ribs 224, 226 against each other is in the Fig. 7 indicated by arrows 340, 342, 344, 346.

[0144] Fig. Figure 10 shows a highly schematic top view of the optical system 100B.

[0145] In the Fig. Figure 10 specifically shows only the second component 104. Components 102 and 104 are connected to each other by means of at least two connecting devices 228 as previously mentioned. The first comb elements 236 and 238 of the two connecting devices face each other, and the second comb elements 256 and 258 face away from each other. A reverse arrangement is also possible.

[0146] The two components 102, 104 are connected to each other at connection points 348, 350, 352, 354, in particular by screws. This creates a positive-locking connection between the first component 102 and the second component 104 in a direction perpendicular to the interface planes 114, 116, as previously explained with reference to connection points 208, 210, 212, 214. Using the connecting devices 228, a force-locking or friction-locking connection can now be created in a respective direction of action 356, 358, 360, 362 perpendicular to the two interface planes 114, 116. The directions of action 356, 358, 360, 362 are oriented parallel to the interface planes 114, 116.

[0147] Fig. Figure 11 shows a schematic view of another embodiment of an optical system 100C.

[0148] All statements concerning optical systems 100A and 100B are applicable to optical systems 100C and vice versa. Optical system 100C comprises a first component 102, as previously mentioned, and a second component 104. Interface levels 114 and 116, as previously mentioned, are assigned to components 102 and 104, which are described in the Fig. However, 11 are not shown.

[0149] The first component 102 comprises a first mounting web 224 as previously mentioned. The first mounting web 224 is curved in an arc. The second component 104 comprises a second mounting web 226 as previously described. The second mounting web 226 is curved in an arc. The components 102 and 104 are connected to each other by means of a connecting device 364. The connecting device 364 comprises a connecting unit 366, which is arranged between the mounting webs 224 and 226.

[0150] Fig. Figure 12 shows a schematic exploded view of an embodiment of a connecting device 364 as previously mentioned.

[0151] The connecting unit 366 comprises a first comb element 368 and a second comb element 370. Thus, the optical system 100C differs from the optical system 100B only in that instead of four comb elements 236, 238, 256, 258, only two comb elements 368, 370 are provided.

[0152] The mounting platforms 224, 226 have mounting surfaces 232, 234 as previously mentioned. The first comb element 368 comprises a base section 372 with a mounting surface 374 facing the mounting surface 232. Two comb sections 376, 378 extend from the base section 372. Each comb section 376, 378 has an opening 380, 382. A fastening element 302 as previously mentioned can be inserted through each of the openings 380, 382. Fig. 9) through which. Base section 372 further includes a borehole 384 oriented perpendicular to breakthroughs 380, 382.

[0153] The second comb element 370 comprises a base section 386 with a mounting surface 388 facing the mounting surface 234. Two comb sections 390, 392 extend from the base section 386. The comb sections 376, 378 of the first comb element 368 are inserted into the comb sections 390, 392 of the second comb element 370. Each comb section 390, 392 may have an opening 394, 396. A bore 398 extends through the base section 386 and is oriented perpendicular to the openings 394, 396.

[0154] A support element 400 is arranged between the contact surface 232 of the first contact web 224 and the contact surface 374 of the first comb element 368. The support element 400 comprises a contact surface 402 facing contact surface 232 and a contact surface 404 facing contact surface 374. A support element 406 is arranged between the second contact web 226 and the second comb element 370. The support element 406 comprises a contact surface 408 facing contact surface 234 and a contact surface 410 facing contact surface 388. The support elements 400 and 406 can be of identical construction. The support elements 400 and 406 can have the previously described cutouts 170 and 172 (not shown).

[0155] Now returning to the Fig. 11 A fastening element 412 for pre-tensioning the connecting device 364 can be passed through the bores 384, 398. For this purpose, the support webs 224, 226 also have openings 414, 416 through which the fastening element 412 is passed. Washers 418, 420 can be arranged between the support webs 224, 226 and the fastening element 412. A pre-tensioning of the support webs 224, 226 against each other is possible in the Fig. 11 shown with the help of arrows 422, 424.

[0156] One functionality of optical system 100C corresponds to the functionality of optical system 100B, which was previously described with reference to the Fig. 10 was explained. In other words, a friction-fit or force-fit connection between the components can also be achieved with the help of the connecting device 364, which leads to a fixing of the components 102, 104 to one another in parallel to the interface levels 114, 116.

[0157] The purpose of the two embodiments of the optical system 100B and 100C described above is to implement an adjustable frictional connection as a safeguard against lateral displacement of the components 102 and 104 relative to each other. This is achieved in particular as a supplement to the connection points 348, 350, 352, and 354. The two different embodiments of the connection device 228 and 364 also enable passive compensation for thermal expansion.

[0158] In optical system 100B, the comb elements 236, 238, 256, 258 are configured as separate pairs, specifically in the form of a comb element arrangement 300 as previously described. By appropriately positioning the comb elements 236, 238, 256, 258 using the fastening elements 308, 310, 312, 314, a specific direction of thermal expansion is achieved, corresponding to a wedge angle of the contact webs 224, 226, thus enabling thermal expansion with minimal or even no additional mechanical stress in the connection device 228. For this purpose, the optional shims 276, 278, 288, 290 can be used, positioned between the comb elements 236, 238, 256, 258 and the contact webs 224, 226. The shims 276, 278, 288, 290 can be geometrically adapted to uneven surfaces under prestressing forces and / or compression using the relief cuts 170, 172.

[0159] To increase the stiffness of the connecting device 228, the contact webs 224, 226 can be pre-tensioned using the fastening elements 316, 318. This means that gaps or incomplete contact surfaces, for example due to unevenness, manufacturing tolerances, roughness, or the like, are reduced by pre-tensioning the fastening elements 316, 318. This results in improved stiffness and force transmission.

[0160] The fasteners 316, 318 can be located either centrally between the comb elements 236, 238, 256, 258 or externally on the comb elements 236, 238, 256, 258. Beneath the screw head and nut of each fastener 316, 318 are the aforementioned washers 328, 330, 332, 334. These washers 328, 330, 332, 334 are made of a material or material combination that deforms or changes in height when exposed to temperature. This allows for compensation of any loss of preload.

[0161] In contrast, optical system 100C provides only two one-piece comb elements 368, 370. The support elements 400, 406 are also each designed as individual parts; however, these support elements have a corresponding arc shape, curvature, or V-shaped geometry to allow adaptation to the mounting surfaces 224, 226. Both embodiments of optical system 100B, 100C enable an adjustable and simultaneously stable or rigid connection that can adapt to geometric deviations, unevenness, or inclinations of the mounting surfaces 224, 226.

[0162] To compensate for thermal expansion in the comb elements 236, 238, 256, 258, 368, 370, a specific geometric design is required, achieved through its shape, position, and / or orientation with a corresponding angular position of the contact webs 224, 226. The aim is to enable thermal expansion with minimal mechanical stress, or even without any mechanical stress at all, or to passively compensate for it. The components should therefore have sufficient degrees of freedom, as well as suitable shapes and orientations, so that they can expand freely and without restrictions. The selection of suitable material combinations for the connecting parts, achieving a coefficient of thermal expansion (CTE) that matches that of ceramics, also contributes to this.

[0163] 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 100A optical system 100B optical system 100C optical system 102 components 104 components 106 Front 108 reverse 110 Front 112 reverse 114 Interface level 116 Interface level 118 jetty 120 jetty 122 Connection device 124 connection unit 126 m² of installation area 128 site area 130 support disc 132 Breakthrough 134 outdoor area 136 Circumferential support element 138 Circumferential support element 140 excerpt 142 m² of plant area 144 square meters of plant area 146 Breakthrough 148 Fastening element 150 slotted hole 152 Excerpt 154 square meters of plant area 156 m² of plant area 158 Breakthrough 160 fastening element 162 Slotted hole 164 support element 166 m² of plant area 168 site area 170 Clearing 172 Clearing 174 Support element 176 m² of plant area 178 site area 180 fastening element 182 Fastening element 184 Breakthrough 186 Breakthrough 188 Breakthrough 190 Breakthrough 192 Washer 194 Washer 196 Washer 198 Washer 200 arrow 202 Arrow 204 Arrow 206 Arrow 208 Connection point 210 Connection point 212 Connection point 214 Connection point 216 Direction of action 218 Direction of action 220 Direction of action 222 Direction of action 224 jetty 226 jetty 228 Connection device 230 connection unit 232 site area 234 m² of plant area 236 comb element 238 Comb element 240 Base section 242 Basic section 244 ridge section 246 ridge section 248 Breakthrough 250 Breakthrough 252 site area 254 square meters of plant area 256 comb element 258 comb element 260 Base section 262 Basic section 264 Ridge section 266 Ridge section 268 Breakthrough 270 Breakthrough 272 site area 274 square meters of plant area 276 support element 278 support element 280 m² of installation area 282 site area 284 square meters of plant area 286 m² of plant area 288 support element 290 support element 292 m² of plant area 294 m² of plant area 296 m² of plant area 298 site area 300 comb element arrangement 302 Fastening element 304 Breakthrough 306 Breakthrough 308 Fastening element 310 Fastening element 312 Fastening element 314 Fastener 316 Fastening element 318 Fastening element 320 Breakthrough 322 Breakthrough 324 Breakthrough 326 Breakthrough 328 Washer 330 Washer 332 Washer 334 Washer 336 Geometry 338 Geometry 340 Arrow 342 Arrow 344 Arrow 346 Arrow 348 Connection point 350 connection point 352 Connection point 354 Connection point 356 Direction of action 358 Direction of action 360° direction of action 362 Direction of action 364 Connection device 366 Connection unit 368 comb element 370 comb element 372 Base section 374 site area 376 Ridge section 378 Ridge section 380 Breakthrough 382 Breakthrough 384 bore 386 Base section 388 site area 390 ridge section 392 Ridge section 394 Breakthrough 396 Breakthrough 398 bore 400 support element 402 Plant area 404 Plant area 406 Support element 408 Plant area 410 m² of installation area 412 Fastening element 414 Breakthrough 416 Breakthrough 418 Washer 420 Washer 422 Arrow 424 Arrow 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 [0066, 0070] US 2006 / 0132747 A1

[0068] EP 1 614 008 B1

[0068] US 6,573,978

[0068] DE 10 2017 220 586 A1

[0073] US 2018 / 0074303 A1

[0087]

Claims

Optical system (100A, 100B, 100C) for a projection exposure system (1), comprising a first component (102) having at least one local first interface level (114), a second component (104) having at least one local second interface level (116), and a connecting device (122, 228, 364) for connecting the first component (102) to the second component (104), wherein the connecting device (122, 228, 364) secures the first component (102) and the second component (104) to each other in a direction of action (216, 218, 220, 222, 356, 358, 360, 362) oriented parallel to the first interface level (114) and / or parallel to the second interface level (116) by positive locking and / or friction locking. Optical system according to claim 1, comprising several connecting devices (122, 228, 364), wherein each connecting device (122, 228, 364) is assigned a direction of action (216, 218, 220, 222, 356, 358, 360, 362), and wherein the directions of action (216, 218, 220, 222, 356, 358, 360, 362) are at least partially oriented differently. Optical system according to claim 1 or 2, wherein the first component (102) and the second component (104) are connected to each other at at least one connection point (208, 210, 212, 214, 348, 350, 352, 354) by means of a positive locking connection, and wherein the positive locking connection acts perpendicular to the first interface plane (114) and perpendicular to the second interface plane (116). Optical system according to one of claims 1-3, wherein the connecting device (122, 228, 364) has a first contact web (118, 224) which is fixedly connected to the first component (102) and a second contact web (120, 226) which is fixedly connected to the second component (104), and wherein the connecting device (122, 228, 364) has a connecting unit (124, 230, 366) which is arranged between the first contact web (118, 224) and the second contact web (120, 226). Optical system according to claim 4, wherein the connecting unit (124, 230, 366) is subjected to a preload force by means of a fastening element (180, 182, 316, 318, 412) between the first contact web (118, 224) and the second contact web (120, 226). Optical system according to claim 4 or 5, wherein the first mounting rib (118, 224) and the second mounting rib (120, 226) are oriented obliquely to each other. Optical system according to one of claims 4 - 6, wherein the first mounting rib (118, 224) and the second mounting rib (120, 226) are straight, curved in an arc or V-shaped. Optical system according to one of claims 4-7, wherein the connecting unit (124) has several lamellar first circumferential support elements (136), several lamellar second circumferential support elements (138) and a support disk (130) on which the first circumferential support elements (136) and the second circumferential support elements (138) bear circumferentially, wherein the support disk (130) is arranged between the first circumferential support elements (136) and the second circumferential support elements (138), wherein the first circumferential support elements (136) and the second circumferential support elements (138) are arranged between the first contact web (118) and the second contact web (120), wherein the first circumferential support elements (136) and the support disk (130) are in particular formed in one piece, or wherein the second circumferential support elements (138) and the support disk (130) are in particular formed in one piece. Optical system according to claim 8, wherein the first circumferential support elements (136) and the second circumferential support elements (136) are connected to the first component (102) or to the second component (104) by means of fastening elements (148, 160). Optical system according to claim 8 or 9, comprising a support element (164, 174) arranged between the first support rib (118) and the first circumferential support elements (136) and / or between the second support rib (120) and the second circumferential support elements (138). Optical system according to claim 10, wherein the support element (164, 174) has cutouts (170, 172). Optical system according to one of claims 4-7, wherein the connecting unit (230) has first comb elements (236, 238) and second comb elements (256, 258), wherein the first comb elements (236, 238) are connected to the first mounting rib (224), wherein the second comb elements (256, 258) are connected to the second mounting rib (226), and wherein comb sections (244, 246) of the first comb elements (236, 238) and comb sections (264, 266) of the second comb elements (256, 258) interlock in a comb-like manner. Optical system according to one of claims 4-7, wherein the connecting unit (366) has exactly one first comb element (368) and exactly one second comb element (370), wherein the first comb element (368) is connected to the first mounting rib (224), wherein the second comb element (370) is connected to the second mounting rib (226), and wherein comb sections (376, 378) of the first comb element (368) and comb sections (390, 392) of the second comb element (370) interlock in a comb-like manner. Optical system according to claim 12 or 13, wherein the comb sections (244, 246, 264, 266, 376, 378, 390, 392) are each connected to each other by means of a fastening element (302) in a force-fit manner. Projection exposure system (1) with an optical system (100A, 100B, 100C) according to one of claims 1 - 14 .

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