DE102024203514A1 - CLAMPING DEVICE, OPTICAL SYSTEM AND PROJECTION EXPOSURE SYSTEM - Google Patents

Abstract

A clamping device (200) for clamping a first component (122) of an optical system (100) to a second component (124) of the optical system (100), comprising a first bearing prism (202) for placing on a first contact surface (126) of the first component (122), a second bearing prism (212) for placing on a second contact surface (132) of the second component (124), wherein the first contact surface (126) and the second contact surface (132) are arranged facing away from each other, and a clamping device (214) for applying a clamping force (K) to both the first bearing prism (202) and the second bearing prism (212) in order to clamp the first component (122) and the second component (124) to each other with the aid of the clamping forces (K), wherein the clamping device (214) has a first Bearing cylinder (232) which is mounted on the clamping device (214) so as to be rotatable about a first axis of rotation (238), wherein the clamping device (214) has a second bearing cylinder (244) which rests on the second bearing prism (212) and is mounted on the clamping device (214) so as to be rotatable about a second axis of rotation (250), and wherein the first axis of rotation (238) and the second axis of rotation (250) are oriented perpendicular to one another.

Description

The present invention relates to a clamping device, an optical system with such a clamping device and a projection exposure system with such a clamping device and/or such an optical system.

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

Driven by the pursuit of ever smaller structures in the manufacture of integrated circuits, EUV lithography systems are currently being developed that use light with a wavelength in the range of 0.1 nm to 30 nm, in particular 13.5 nm. In such EUV lithography systems, reflective optics, i.e. mirrors, must be used instead of - as previously - refractive optics, i.e. lenses, due to the high absorption of light of this wavelength by most materials.

A projection system as mentioned above can have a so-called sensor frame. This can be made up of several ceramic sub-components or components. Since screwing is only possible with ceramic materials if so-called threaded inserts are used, it can be advantageous to clamp the components of the sensor frame together. According to internal company knowledge, clamping devices can be used for this purpose, which engage in spherical cap-shaped bearing elements that are glued to the components.

Against this background, an object of the present invention is to provide an improved clamping device.

Accordingly, a clamping device for clamping a first component of an optical system to a second component of the optical system is proposed. The clamping device comprises a first bearing prism for placing on a first contact surface of the first component, a second bearing prism for placing on a second contact surface of the second component, wherein the first contact surface and the second contact surface are arranged facing away from each other, and a clamping device for applying a clamping force to both the first bearing prism and the second bearing prism in order to clamp the first component and the second component to each other with the aid of the clamping forces, wherein the clamping device has a first bearing cylinder which rests on the first bearing prism and is mounted on the clamping device so as to be rotatable about a first axis of rotation, wherein the clamping device has a second bearing cylinder which rests on the second bearing prism and is mounted on the clamping device so as to be rotatable about a second axis of rotation, and wherein the first axis of rotation and the second axis of rotation are oriented perpendicular to each other.

Because the bearing cylinders are mounted in the bearing prisms and because the first axis of rotation and the second axis of rotation are arranged perpendicular to each other, it is possible to compensate for any incorrect positioning of the components, the bearing prisms and/or the clamping device itself on the bearing cylinders. Since a larger lever arm can be achieved with such a bearing cylinder compared to a spherical cap, larger alignment forces are therefore effective, which also allows better alignment to be achieved.

Any number of clamping devices can be used to clamp the first component and the second component. This means in particular that the optical system can have any number of clamping devices. Reference is made below to only one clamping device. The first component and the second component are preferably parts of a sensor frame of the optical system. The first component and the second component are particularly preferably each made of a ceramic material.

The first bearing prism and the second bearing prism are preferably constructed identically. Therefore, only a bearing prism is discussed in general terms below. The bearing prism has a flat support surface with which the bearing prism rests either on the first contact surface of the first component or on the second contact surface of the second component. Away from the support surface, the bearing prism has two bearing surfaces arranged perpendicular to each other, against which the respective bearing cylinder rests with a line contact. As soon as the bearing cylinder is inserted into the respective bearing prism, The bearing cylinder rests on the bearing surfaces of the bearing prism.

The first bearing prism can, for example, be glued to the first contact surface of the first component. Accordingly, the second bearing prism can be glued to the second contact surface of the second component. Thus, the first bearing prism is used in particular for gluing to the first contact surface of the first component. Accordingly, the second bearing prism is used in particular for gluing to the second contact surface of the second component. Any number of bearing prisms can be assigned to each component. Each clamping device preferably has exactly two bearing prisms.

The clamping device differs from the clamping device in that the clamping device preferably does not have the bearing prisms, which can be connected to the components. The clamping device, on the other hand, comprises both the clamping device and the bearing prisms. The clamping device or the clamping device is designed to grip the two components like a pair of pliers and to apply a clamping force to each of the components, so that the two components are pressed against one another with the aid of the clamping forces and thus clamped together. This creates a force-fit connection between the two components.

The first bearing cylinder preferably has a fastening section, with the aid of which the first bearing cylinder is connected to the clamping device so that it can rotate about the first axis of rotation. Accordingly, the second bearing cylinder preferably also has such a fastening section, with the aid of which the second bearing cylinder is connected to the clamping device so that it can rotate about the second axis of rotation. In this case, “perpendicular” is to be understood in particular as an angle of 90° ± 10°, preferably 90° ± 5°, more preferably 90° ± 3°, more preferably 90° ± 1°, more preferably exactly 90°.

According to one embodiment, the first axis of rotation is oriented perpendicular to the first contact surface and the second axis of rotation is oriented parallel to the second contact surface, or the first axis of rotation is parallel to the first contact surface and the second axis of rotation is oriented perpendicular to the second contact surface.

Accordingly, the clamping device can be mounted in reverse. In the latter case, the second bearing cylinder is assigned to the first bearing prism and the second bearing cylinder to the second bearing prism. This results in the orientation of the rotation axes being reversed. The clamping device can therefore be mounted in any way.

According to a further embodiment, the first bearing cylinder has a first axis of symmetry, to which the first bearing cylinder is constructed rotationally symmetrically, wherein the first axis of rotation is oriented perpendicular to the first axis of symmetry, wherein the second bearing cylinder has a second axis of symmetry, to which the second bearing cylinder is constructed rotationally symmetrically, wherein the second axis of rotation is oriented perpendicular to the second axis of symmetry, and wherein the first axis of symmetry and the second axis of symmetry are oriented parallel to one another or obliquely to one another.

Ideally, the first axis of symmetry and the second axis of symmetry are oriented parallel to each other. However, the clamping device can compensate for an inclination of the first axis of symmetry to the second axis of symmetry. This is made possible by the fact that the first axis of rotation of the first bearing cylinder is oriented perpendicular to the second axis of rotation of the second bearing cylinder.

According to a further embodiment, the clamping device has a base body with a hook-shaped base body bearing section, wherein the first bearing cylinder is mounted on the base body bearing section so as to be rotatable about the first axis of rotation.

The base body can in particular have a C-shaped geometry, wherein the base body bearing section forms one leg of this C-shaped geometry. The base body bearing section can have a recess facing the first bearing cylinder, which enables the first bearing cylinder to pivot about the first axis of rotation in this recess.

According to a further embodiment, the first bearing cylinder is connected to the base body bearing section by means of a first fastening element, in particular by means of a screw.

The bearing cylinder preferably comprises a cylindrical fastening section which is constructed rotationally symmetrically to the first axis of rotation. The fastening element can be screwed into this fastening section.

According to a further embodiment, the clamping device has a clamping body which is pivotably mounted on the base body, wherein the second bearing cylinder is pivotable about the second The axis of rotation is rotatably mounted on the clamping body.

The base body preferably comprises a first bearing arm and a second bearing arm, with the clamping body being arranged between the two bearing arms. The clamping body can be rotatably mounted on the base body with the aid of an axis. The second bearing cylinder preferably comprises a cylindrical fastening section which is rotatably mounted in a recess provided on the clamping body. This fastening section is preferably constructed rotationally symmetrically to the second axis of rotation.

According to a further embodiment, the second bearing cylinder is connected to the clamping body by means of a second fastening element, in particular by means of a screw.

The second fastening element can be passed through the aforementioned fastening section of the second bearing cylinder and screwed to the clamping body.

According to a further embodiment, the clamping device has a clamping element, with the aid of which the clamping body can be pivoted relative to the base body in order to generate the clamping force.

The clamping element can be, for example, a screw that can be screwed into a threaded hole provided on the base body. The clamping element contacts the clamping body, so that by moving the clamping element in the base body, the clamping body can be pivoted relative to the base body in order to apply the clamping forces to the bearing prisms and thus also to the components in order to clamp the components together.

Furthermore, an optical system for a projection exposure system is proposed. The optical system comprises a first component, a second component and such a clamping device, wherein the clamping device applies a clamping force to both the first bearing prism and the second bearing prism, so that the first component and the second component are clamped together with the aid of the clamping forces.

The optical system is preferably a projection optics of the projection exposure system or part of such a projection optics. However, the optical system can also be an illumination system of the projection exposure system or part of such an illumination system. The optical system can have any number of optical elements, in particular mirrors. In addition to the optical elements, the optical system can have a support frame and a sensor frame. The support frame supports the optical elements and the sensor frame. The sensor frame is made up of several parts. The first component and the second component are preferably part of the sensor frame.

Furthermore, a projection exposure system with such a clamping device and/or such an optical system is proposed.

The projection exposure system can be an EUV lithography system. EUV stands for “Extreme Ultraviolet” and describes 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 describes a wavelength of the working light between 30 nm and 250 nm.

In this case, "one" is not necessarily to be understood as being limited to just one element. Rather, several elements, such as two, three or more, can also be provided. Any other counting word used here is also not to be understood as meaning that there is a limitation to the exact number of elements mentioned. Rather, numerical deviations upwards and downwards are possible, unless otherwise stated.

The embodiments and features described for the proposed clamping device apply to the proposed optical system and to the proposed projection exposure system accordingly and vice versa.

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

• 1 zeigt einen schematischen Meridionalschnitt einer Projektionsbelichtungsanlage für die EUV-Projektionslithographie;
• 2 zeigt eine schematische Ansicht einer Ausführungsform eines optischen Systems für die Projektionsbelichtungsanlage gemäß 1;
• 3 zeigt eine schematische perspektivische Ansicht einer Ausführungsform einer Klemmvorrichtung für das optische System gemäß 2;
• 4 zeigt eine weitere schematische perspektivische Ansicht der Klemmvorrichtung gemäß 3; und
• 5 zeigt eine weitere schematische perspektivische Ansicht der Klemmvorrichtung gemäß 3.

Further advantageous embodiments and aspects of the invention are the subject of the subclaims and the embodiments of the invention described below. The invention is explained in more detail below using preferred embodiments with reference to the attached figures.

• 1 shows a schematic meridional section of a projection exposure system for EUV projection lithography;
• 2 shows a schematic view of an embodiment of an optical system for the projection exposure apparatus according to 1 ;
• 3 shows a schematic perspective view of an embodiment of a clamping device for the optical system according to 2 ;
• 4 shows a further schematic perspective view of the clamping device according to 3 ; and
• 5 shows a further schematic perspective view of the clamping device according to 3 .

In the figures, identical or functionally equivalent elements have been given the same reference symbols unless otherwise stated. It should also be noted that the representations in the figures are not necessarily to scale.

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

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

In the 1 For explanation purposes, a Cartesian coordinate system with an x-direction x, a y-direction y and a z-direction z is shown. The x-direction x runs perpendicularly into the plane of the drawing. The y-direction y runs horizontally and the z-direction z runs vertically. The scanning direction runs in the 1 along the y-direction y. The z-direction z runs perpendicular to the object plane 6.

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

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

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

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

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.

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

The first facets 21 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or partially circular edge contour. The first facets 21 can be designed as flat facets or alternatively as convex or concave curved facets.

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

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

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

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.

The second facets 23 can also be macroscopic facets, which can be round, rectangular or hexagonal, for example, or alternatively facets composed of micromirrors. In this regard, reference is also made to the DE 10 2008 009 600 A1 referred to.

The second facets 23 can have planar or alternatively convex or concave curved reflection surfaces.

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

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

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

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

The lighting optics 4 have in the version shown in the 1 As shown, after the collector 17 there are exactly three mirrors, namely the deflection mirror 19, the first facet mirror 20 and the second facet mirror 22.

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

The imaging of the first facets 21 by means of the second facets 23 or with the second facets 23 and a transmission optics in the object level 6 is usually only an approximate image.

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

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

Reflection surfaces of the mirrors Mi can be designed as free-form surfaces without a rotational symmetry axis. Alternatively, the reflection surfaces of the mirrors Mi can be designed as aspherical surfaces with exactly one rotational symmetry axis of the reflection surface shape. The mirrors Mi, just 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.

The projection optics 10 have 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.

The projection optics 10 can in particular be anamorphic. In particular, it has different image scales βx, βy in the x and y directions x, y. The two image scales βx, βy of the projection optics 10 are preferably (βx, βy) = (+/- 0.25, +/- 0.125). A positive image scale β means an image without image inversion. A negative sign for the image scale β means an image with image inversion.

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

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

Other image scales are also possible. Image scales with the same sign and absolutely the same in the x and y directions x, y, for example with absolute values of 0.125 or 0.25, are also possible.

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

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

The first facets 21 are each imaged onto the reticle 7 by an associated second facet 23, superimposing one another, to illuminate the object field 5. The illumination of the object field 5 is in particular as homogeneous as possible.

It preferably has a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.

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

A likewise preferred pupil uniformity in the area of defined illuminated sections of an illumination pupil of the illumination optics 4 can be achieved by a redistribution of the illumination channels.

In the following, further aspects and details of the illumination of the object field 5 and in particular of the entrance pupil of the projection optics 10 are described.

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

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

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

In the 1 In the arrangement of the components of the illumination optics 4 shown, the second facet mirror 22 is arranged in a surface conjugated to the entrance pupil of the projection optics 10. The first facet mirror 20 is arranged tilted to the object plane 6. The first facet mirror 20 is arranged tilted to an arrangement plane that is defined by the deflection mirror 19. The first facet mirror 20 is arranged tilted to an arrangement plane that is defined by the second facet mirror 22.

2 shows a schematic view of an embodiment of an optical system 100 for the projection exposure apparatus 1.

The optical system 100 can be a projection optics 10 as mentioned above or part of such a projection optics 10. Therefore, the optical system 100 can also be referred to as projection optics. However, the optical system 100 can also be an illumination system 2 as explained above or part of such an illumination system 2. Therefore, the optical system 100 can alternatively also be referred to as an illumination system.

However, it is assumed below that the optical system 100 is a projection optics 10 or part of such a projection optics 10. The optical system 100 is suitable for EUV lithography. However, the optical system 100 can also be suitable for DUV lithography.

The optical system 100 may comprise a plurality of optical elements 102, of which 2 however, only one is shown. Therefore, only one optical element 102 is discussed below. The optical element 102 can be one of the mirrors M1 to M6. Accordingly, the optical element 102 is a mirror, in particular an EUV mirror. However, the optical element 102 can also be a lens.

In addition to the optical element 102, the optical system has a support frame 104 (force frame) and a sensor frame 106 (sensor frame). The support frame 104 is coupled to a fixed world 110 using a coupling element 108. The coupling element 108 can comprise springs. Several such coupling elements 108 can be provided. In the present case, a "fixed world" is understood to mean an area of the optical system 100 that is immobile with respect to the support frame 104. For example, the fixed world 110 can be a base frame of the optical system 100.

The sensor frame 106 is coupled to the support frame 104 by means of a coupling element 112. The coupling element 112 can comprise springs. Several such coupling elements 112 can be provided. The support frame 104 thus supports the sensor frame 106. In other words, the sensor frame 106 is not coupled directly to the fixed world 110, but indirectly or indirectly via the support frame 104.

The optical element 102 can be adjusted or aligned in six degrees of freedom using an actuator unit 114. This allows a position of the optical element 102 to be changed. For example, the optical element 102 can be moved from an actual position in which the optical element 102 does not meet certain optical specifications to a desired target position in which the optical element 102 meets the optical specifications. The sensor frame 106 serves as a reference for a change in position of the optical element 102 as mentioned above. The optical element 102 is connected to the support frame 104 via the actuator unit 114. The optical element 102 can be connected to the actuator unit 114 using a coupling element 116, which in turn is connected to the support frame 104 via a coupling element 118. The coupling elements 116, 118 can have springs. Any number of coupling elements 116, 118 can be provided.

With the help of a control and regulating unit 120, for example, a target position of the optical element 102 as mentioned above is maintained. The control and regulating unit 120 can communicate with the actuator unit 114, which aligns or adjusts the optical element 102 based on control signals from the control and regulating unit 120. The control and regulating unit 120 interacts with the sensor frame 106 in such a way that, for example, sensors attached to the sensor frame 106 measure the optical element 102, the control and regulating unit 120 controlling the actuator unit 114 based on sensor signals from these sensors in order to maintain the target position of the optical element 102.

The sensor frame 106 is made of a ceramic material. The sensor frame 106 can be constructed from different parts or components that are connected to one another. Since the introduction of threads into ceramic materials cannot usually be achieved without so-called thread inserts, it can be advantageous to clamp the components of the sensor frame 106 together.

3 shows a schematic perspective view of an embodiment of a clamping device 200 for the optical system 100. 4 shows another schematic perspective view of the clamping device 200. 5 shows a further schematic perspective view of the clamping device 200. The following is the 3 to 5 simultaneously referred to.

The optical system 100 can have any number of clamping devices 200. However, reference is made below to only one clamping device 200. The clamping device 200 can be part of the sensor frame 106. However, this is not absolutely necessary. As previously mentioned, the sensor frame 106 can comprise several parts or components.

In the 3 and 4 a first component 122 and a second component 124 of the sensor frame 106 are shown. However, the components 122, 124 can basically be any components of the optical system 100. The components 122, 124 can have any geometry. In the 3 and 4 The components 122, 124 are shown in a simplified manner as block-shaped components. The components 122, 124 can also be referred to as sensor frame components. The components 122, 124 are made of a ceramic material.

The first component 122 has the orientation of the 3 and 4 a first contact surface 126 on the top side. The first component 122 has a second contact surface 128 facing away from the first contact surface 126. The second contact surface 128 faces the second component 124, with the first contact surface 126 facing away from the second component 124.

The second component 124 comprises a first contact surface 130, against which the second contact surface 128 of the first component 122 rests. Facing away from the first contact surface 130, and thus also facing away from the first contact surface 126 of the first component 122, the second component 124 has a second contact surface 132. In the orientation of the 3 and 4 Thus, the first contact surface 126 of the first component 122 points upwards and the second contact surface 132 of the second component 124 points downwards.

The clamping device 200 is now designed to press the first component 122 and the second component 124 together at the contact surfaces 128, 130 by applying clamping forces K to the contact surfaces 126, 132 with the aid of the clamping device 200. This creates a force-locking connection between the first component 122 and the second component 124. A force-locking connection requires a normal force, namely the clamping forces K, on the surfaces to be connected to one another, in this case the contact surfaces 128, 130. Force-locking connections can be created by frictional engagement. The mutual displacement of the surfaces is prevented as long as a counterforce caused by the static friction is not exceeded.

The clamping device 200 is made up of several parts. The clamping device 200 has a first bearing prism 202, which rests on the first contact surface 126 of the first component 122. The first bearing prism 202 can be glued to the first contact surface 126. The first bearing prism 202 is block-shaped and has a support surface 204, with which the first bearing prism 202 rests on the first contact surface 126 of the first component 122. The support surface 204 can be glued to the first contact surface 126 of the first component 122.

Furthermore, the first bearing prism 202 comprises two bearing surfaces 206, 208 facing away from the support surface 204, which are oriented at a 90° angle to one another. This results in a V-shaped cross section of the first bearing prism 202. Perpendicular to the bearing surfaces 206, 208, the first bearing prism 202 has a recess 210 in the shape of a circular arc, which breaks through the bearing surfaces 206, 208 at least in sections.

Furthermore, the clamping device 200 comprises a second bearing prism 212, which is identical to the first bearing prism 202 is constructed. Therefore, the construction of the second bearing prism 212 will not be discussed in detail below. The two bearing prisms 202, 212 are positioned mirror-symmetrically, so that the bearing surfaces 206, 208 of the two bearing prisms 202, 212 face away from each other and the two support surfaces 204 of the two bearing prisms 202, 212 face each other. The second bearing prism 212 rests with its support surface 204 on the second contact surface 132 of the second component 124. For example, the second bearing prism 212 is glued to the second contact surface 132 of the second component 124.

In addition to the two bearing prisms 202, 212, the clamping device 200 has a clamping device 214. The clamping device 214 is made up of several parts. The clamping device 214 has a base body 216. The base body 216 has a C-shaped geometry and can thus encompass the two components 122, 124. This means that the two components 122, 124 can be arranged at least in sections within the base body 216.

The base body 216 has a hook-shaped base body bearing section 218. On the base body bearing section 218, in the orientation of the 3 to 5 a recess 220 is provided on the underside. Two bearing arms 222, 224 extend out of the base body 216 on the underside. A clamping body 228 of the clamping device 214 is mounted on the two bearing arms 222, 224 so as to be pivotable relative to the base body 216 about an axis 226. The clamping body 228 is placed between the two bearing arms 222, 224. The clamping body 228 comprises in the orientation of the 3 to 5 a recess 230 on the upper side. The recess 230 can be cylindrical at least in sections.

The clamping device 214 has a first bearing cylinder 232 which rests on the first bearing prism 202, in particular on the two bearing surfaces 206, 208. The first bearing cylinder 232 is designed to be rotationally symmetrical to a first central or symmetry axis 234. In particular, a bearing section 236 of the first bearing cylinder 232 is designed to be rotationally symmetrical to the first symmetry axis 234. The first bearing cylinder 232 is mounted on the clamping device 214, in particular on the base body bearing section 218 of the base body 216, so as to be rotatable about a first axis of rotation 238. The first axis of rotation 238 is oriented perpendicular to the first contact surface 126 and perpendicular to the first axis of symmetry 234. The first axis of symmetry 234 is in turn oriented parallel to the first contact surface 126.

The first bearing cylinder 232 has a cylindrical fastening section 240 that extends out of the bearing section 236. With the help of the fastening section 240, the first bearing cylinder 232 is rotatably mounted in the main body bearing section 218 about the first axis of rotation 238. The first bearing cylinder 232 can move in the recess 220 about the first axis of rotation 238. The first bearing cylinder 232 is connected to the main body bearing section 218 with the help of a first fastening element 242, in particular in the form of a screw. The first fastening element 242 is guided through the main body bearing section 218 and connected to the fastening section 240 of the first bearing cylinder 232.

In addition to the first bearing cylinder 232, the clamping device 214 comprises a second bearing cylinder 244, which rests on the second bearing prism 212, in particular on the two bearing surfaces 206, 208 of the second bearing prism 212. The second bearing cylinder 244 is constructed rotationally symmetrically to a second central or symmetry axis 246. In particular, a bearing section 248 of the second bearing cylinder 244 is constructed rotationally symmetrically to the second symmetry axis 246. The second bearing cylinder 244 is mounted on the clamping device 214, in particular on the clamping body 228, so as to be rotatable about a second axis of rotation 250. The second axis of rotation 250 is arranged perpendicular to the first axis of rotation 238.

Furthermore, the second axis of rotation 250 is also oriented perpendicular to the second axis of symmetry 246. The second axis of rotation 250 runs parallel to the second contact surface 132 of the second component 124. The second bearing cylinder 244 comprises a fastening section 252 which is mounted in the recess 230 of the clamping body 228. The fastening section 252 is formed onto the bearing section 248. The second bearing cylinder 244, in particular its fastening section 252, is connected to the clamping body 228 by means of a second fastening element 254, in particular in the form of a screw. The two axes of symmetry 234, 246 of the two bearing cylinders 232, 244 can be oriented parallel or obliquely to one another.

The clamping device 214 further comprises a clamping element 256 ( 3 ), which is received in a threaded hole provided on the base body 216. With the help of the clamping element 256, the clamping body 228 can be pivoted about the axis 226. For this purpose, the clamping element 256 is screwed into the base body 216. By screwing the clamping element 256 into the base body 216, the clamping element 256 presses on the clamping body 228, which is thereby pivoted relative to the base body 216 in such a way that that the two components 122, 124 are clamped together with the clamping forces K.

The functionality of the clamping device 200 is explained below. First, the first component 122 and the second component 124 are placed on top of one another at their contact surfaces 128, 130. Afterwards or beforehand, the bearing prisms 202, 212 are placed and/or glued onto the first contact surface 126 of the first component and onto the second contact surface 132 of the second component 124.

The clamping device 214 is now positioned such that the first bearing cylinder 232 is received in the first bearing prism 202 and the second bearing cylinder 244 is received in the second bearing prism 212. In particular, the two bearing sections 236, 248 come to rest in the bearing prisms 202, 212. Because the rotation axes 238, 250 of the bearing cylinders 232, 244 are arranged perpendicular to one another, it is possible that, for example, inclinations of the clamping device 214 and/or inclinations of the bearing prisms 202, 212 relative to one another can be compensated for when the clamping element 256 is tightened.

The bearing cylinders 232, 244, in particular their bearing sections 236, 248, align themselves in the bearing prisms 202, 212 without excessive stress being introduced into the components 122, 124. At the same time, however, it is possible to reliably apply the clamping forces K. As the 5 shows, a lever arm or path a is provided from the first axis of rotation 238 to one end of the first bearing cylinder 232, in particular the bearing section 236. The same applies to the second bearing cylinder 244.

This aforementioned path a is as large as possible so that a large leverage effect is possible when aligning the respective bearing cylinder 232, 244 in the associated bearing prism 202, 212. The possibility of rotation of the first bearing cylinder 232 about the first axis of rotation 238 is in the 5 indicated by a double arrow 258. The tiltability of the second bearing cylinder 244 about the second axis of rotation 250 is shown in the 5 indicated by a double arrow 260.

Due to the angle of 90° between the two bearing surfaces 206, 208 of the bearing prisms 202, 212, the bearing prisms 202, 212 have no self-locking and the bearing cylinders 232, 244 always slide into the ideal position. Because the bearing cylinders 232, 244 are mounted in a rotating manner, all incorrect positioning of the bearing prisms 202, 212 when gluing them or assembly inaccuracies of the components 122, 124 can be compensated. It should be noted that the rotation axes 238, 250 of the two bearing cylinders 232, 244 are each rotated by 90°. Only this enables all degrees of freedom, as can be seen with the help of the double arrows 258, 260 in the 5 is indicated.

However, there are also frictional forces in the bearing prisms 202, 212 which work against ideal alignment. In contrast to the use of spherical caps for bearings, the alignment forces are significantly higher. This is due to the length of the bearing cylinders 232, 244. Or in other words, to the path a. The path a generates a significantly higher torque in the bearing and thus better alignment.

The storage using the bearing prisms 202, 212 and the bearing cylinders 232, 244 can be used very well both during assembly and when exchanging (swapping) the components 122, 124 in the field in order to first securely hook the clamping device 214 into the bearing prisms 202, 212. Even when the clamping device 214 is opened, there is a lower risk that the clamping device 214 will slip out of the bearing prisms 202, 212 and cause damage. For this purpose, it would also be possible to enlarge the bearing prisms 202, 212 on one side in order to completely rule out the clamping device 214 slipping out of the bearing prisms 202, 212.

Although the present invention has been described using exemplary embodiments, it can be modified in many ways.

REFERENCE SYMBOL LIST

1

projection exposure system

2

lighting system

3

light source

4

lighting optics

5

object field

6

object level

7

reticle

8

reticle holder

9

reticle displacement drive

10

projection optics

11

image field

12

image plane

13

wafer

14

wafer holder

15

wafer relocation drive

16

illumination radiation

17

collector

18

intermediate focal plane

19

deflecting mirror

20

first faceted mirror

21

first facet

22

second facet mirror

23

second facet

100

optical system

102

optical element

104

supporting frame

106

sensor frame

108

coupling element

110

solid world

112

coupling element

114

actuator unit

116

coupling element

118

coupling element

120

control unit

122

component

124

component

126

contact surface

128

contact surface

130

contact surface

132

contact surface

200

clamping device

202

bearing prism

204

support surface

206

storage space

208

storage space

210

recess

212

bearing prism

214

clamping device

216

base body

218

base body bearing section

220

recess

222

bearing arm

224

bearing arm

226

axis

228

clamping body

230

recess

232

bearing cylinder

234

axis of symmetry

236

storage section

238

axis of rotation

240

fastening section

242

fastener

244

bearing cylinder

246

axis of symmetry

248

storage section

250

axis of rotation

252

fastening section

254

fastener

256

clamping element

258

double arrow

260

double arrow

a

Away

K

clamping force

M1

Mirror

M2

Mirror

M3

Mirror

M4

Mirror

M5

Mirror

M6

Mirror

x

x-direction

y

y-direction

z

z-direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. 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

• DE 10 2008 009 600 A1 [0046, 0050]
• US 2006/0132747 A1 [0048]
• EP 1 614 008 B1 [0048]
• US 6,573,978 [0048]
• DE 10 2017 220 586 A1 [0053]
• US 2018/0074303 A1 [0067]

Claims (10)

Clamping device (200) for clamping a first component (122) of an optical system (100) to a second component (124) of the optical system (100), comprising a first bearing prism (202) for placing on a first contact surface (126) of the first component (122), a second bearing prism (212) for placing on a second contact surface (132) of the second component (124), wherein the first contact surface (126) and the second contact surface (132) are arranged facing away from each other, and a clamping device (214) for applying a clamping force (K) to both the first bearing prism (202) and the second bearing prism (212) in order to clamp the first component (122) and the second component (124) to each other with the aid of the clamping forces (K), wherein the clamping device (214) has a (202) and is mounted on the clamping device (214) so as to be rotatable about a first axis of rotation (238), wherein the clamping device (214) has a second bearing cylinder (244) which is mounted on the second bearing prism (212) and is mounted on the clamping device (214) so as to be rotatable about a second axis of rotation (250), and wherein the first axis of rotation (238) and the second axis of rotation (250) are oriented perpendicular to one another. clamping device according to claim 1 , wherein the first axis of rotation (238) is oriented perpendicular to the first contact surface (126) and the second axis of rotation (250) is oriented parallel to the second contact surface (132), or wherein the first axis of rotation (238) is oriented parallel to the first contact surface (126) and the second axis of rotation (250) is oriented perpendicular to the second contact surface (132). clamping device according to claim 1 or 2 , wherein the first bearing cylinder (232) has a first axis of symmetry (234) to which the first bearing cylinder (232) is rotationally symmetrical, wherein the first axis of rotation (238) is oriented perpendicular to the first axis of symmetry (234), wherein the second bearing cylinder (244) has a second axis of symmetry (246) to which the second bearing cylinder (244) is rotationally symmetrical, wherein the second axis of rotation (250) is oriented perpendicular to the second axis of symmetry (246), and wherein the first axis of symmetry (234) and the second axis of symmetry (246) are oriented parallel to one another or obliquely to one another. Clamping device according to one of the Claims 1 - 3 , wherein the clamping device (214) has a base body (216) with a hook-shaped base body bearing portion (218), and wherein the first bearing cylinder (232) is mounted on the base body bearing portion (218) so as to be rotatable about the first axis of rotation (238). clamping device according to claim 4 , wherein the first bearing cylinder (232) is connected to the base body bearing section (218) by means of a first fastening element (242), in particular by means of a screw. clamping device according to claim 4 or 5 , wherein the clamping device (214) has a clamping body (228) which is pivotably mounted on the base body (216), and wherein the second bearing cylinder (244) is rotatably mounted on the clamping body (228) about the second axis of rotation (250). clamping device according to claim 6 , wherein the second bearing cylinder (244) is connected to the clamping body (228) by means of a second fastening element (254), in particular by means of a screw. clamping device according to claim 6 or 7 , wherein the clamping device (214) has a clamping element (256) with the aid of which the clamping body (228) can be pivoted relative to the base body (216) in order to generate the clamping force (K). Optical system (100) for a projection exposure system (1), comprising a first component (122), a second component (124), and a clamping device (200) according to one of the Claims 1 - 8 , wherein the clamping device (200) applies a clamping force (K) to both the first bearing prism (202) and the second bearing prism (212), so that the first component (122) and the second component (124) are clamped together by means of the clamping forces (K). Projection exposure system (1) with a clamping device (200) according to one of the Claims 1 - 8 and/or an optical system (100) according to claim 9 .

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