Optical system and projection exposure system

Abstract

The invention relates to an optical system (200A, 200B, 200C, 200D) for a projection exposure system (1), comprising a first component (202), a second component (204), wherein the second component (204) can be deflected relative to the first component (202) within a deflection range, and an end stop and vibration absorber device (206A, 206B, 206C, 206D, 206E, 206F) which allows a movement of the second component (204) relative to the first component (202) within the deflection range and blocks same outside the deflection range, and which is designed to damp eigenmodes of the second component (204), wherein the end stop and vibration absorber device (206A, 206B, 206C, 206D, 206E, 206F) is at least partially attached to the second component (204).

Description

[0001] Carl Zeiss SMT GmbH

[0002] 1

[0003] OPTICAL SYSTEM AND PROJECTIONAL LIGHTING SYSTEM

[0004] The present invention relates to an optical system and a projection exposure system with such an optical system.

[0005] The content of priority application DE 102025 107617.0 is fully incorporated by reference.

[0006] 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.

[0007] Driven by the pursuit of ever smaller structures in the production of integrated circuits, EUV lithography systems are currently being developed that use light with a wavelength in the range of 0.1 nm to 30 nm, particularly 13.5 nm. Due to the high absorption of light of this wavelength by most materials, such EUV lithography systems require reflective optics, i.e., mirrors, instead of the previously used refracting optics, i.e., lenses.

[0008] A key component of such projection systems are the high-precision mirrors that reflect, focus, and direct the light. To ensure the proper functioning of these mirrors and protect them from damage, end stops can be used to limit the maximum deflection of the mirrors within their degrees of freedom. Without this limitation, excessive deflection could damage the mirrors, leading to costly repairs and production downtime.

[0009] Such end stops typically comprise a plunger and an elastomer tip, which is designed, for example, as a ring. The plunger can be attached to a support structure outside the respective mirror, for example, to a support frame or a mirror support frame, and is held with clearance in a recess provided in the mirror. This design limits certain degrees of freedom of the mirror in the event of excessive movement. Carl Zeiss SMT GmbH

[0010] 2

[0011] Mirrors are locked, thus limiting the maximum movement amplitude of the mirrors.

[0012] The mirrors' position is controlled in up to six degrees of freedom. This complex control requires effective damping of the mirrors' eigenmodes to prevent amplitude amplification and the associated instability in the control loop. Passive damping is possible, for example, using so-called tuned mass dampers (TMDs). These dampers can be mounted directly on or attached to the mirrors and dampen their eigenmodes through their mechanical properties.

[0013] A challenge arises when using small mirrors or mirrors with specific requirements for the placement of attachments. In these cases, ideal positions for end stops and vibration dampers on the mirrors can overlap, leading to space conflicts. These space conflicts complicate the mounting of the end stops and vibration dampers and impair the efficiency of the damping and deflection limitation of the mirrors.

[0014] Against this background, one object of the present invention is to provide an improved optical system.

[0015] Accordingly, an optical system for a projection exposure system is proposed. The optical system comprises a first component, a second component wherein the second component is deflectable within a deflection range relative to the first component, and an end-stop and vibration damping device which allows movement of the second component relative to the first component within the deflection range and blocks movement outside the deflection range, and which is configured to dampen eigenmodes of the second component, wherein the end-stop and vibration damping device is at least partially attached to the second component.

[0016] Because the endstop and vibration damper device can perform both the functions of an endstop and a vibration damper, the aforementioned space constraints can be effectively resolved, damping efficiency maximized, and the structural integrity of the second component ensured. This can contribute to improved performance and reliability of the optical system. Carl Zeiss SMT GmbH

[0017] 3

[0018] Furthermore, integrating both functions into the end stop and vibration damper device reduces assembly effort, which lowers production costs and simplifies maintenance.

[0019] The optical system is, in particular, a projection optic of the projection lighting system or part of such a projection optic. However, the optical system can also be a lighting system or part of a lighting system. The first and second components can be any components or parts of the optical system. For example, the first component can be a support structure, in particular a force frame, a mirror support frame, or a sensor frame. The second component can, for example, be an optical element, such as a mirror, in particular an EUV mirror. Alternatively, it is also possible, for example, that the first component is a support structure, for example in the form of a force frame, and the second component is another support structure, for example in the form of a sensor frame.In principle, the components can include any optical elements, measuring instruments, support structures, mirror targets, or similar parts of the optical system. The optical system can have any number of end-stop and vibration damping devices. Each end-stop and vibration damping device can be assigned its own deflection range.

[0020] The fact that the second component is deflectable or actuable relative to the first component within a "displacement range" or "actuation range" means, in particular, that the second component can be moved relative to the first component within a certain range of motion, which can be managed, for example, by means of an adjustment device comprising one or more actuators or positioning elements. Accordingly, preferably only the second component is movable or deflectable. The first component is preferably fixed and therefore immobile. The first component can, in particular, be coupled to a so-called fixed world of the optical system.

[0021] The term "deflection" or "actuation" of the second component refers to moving the second component relative to the first component using the adjustment device, in particular the actuator or actuators. The second component is preferably mounted using a weight-compensating bearing. This means, in particular, that the second component can be deflected without force within the deflection range. If a limit of the deflection range is reached, Carl Zeiss SMT GmbH

[0022] 4

[0023] The end stop and vibration damper device blocks any further deflection of the second component relative to the first component.

[0024] With the aid of the aforementioned adjustment device, the position of the second component relative to the first component can be changed. Accordingly, "deflection" or "actuation" of the second component can be understood as a change in its position. The second component can have six degrees of freedom: three translational degrees of freedom along a first spatial direction (x-direction), a second spatial direction (y-direction), and a third spatial direction (z-direction), and three rotational degrees of freedom around the x-direction, the y-direction, and the z-direction. That is, the position and orientation of the second component can be determined or described using these six degrees of freedom.

[0025] The "position" of the second component refers specifically to its coordinates with respect to the x-direction, y-direction, and z-direction. The "orientation" of the second component refers specifically to its tilt with respect to these three directions. This means that the second component can be tilted about the x-direction, the y-direction, and / or the z-direction. This results in the six degrees of freedom for the position and orientation of the second component. The "location" of the second component encompasses both its position and its orientation. The term "location" can therefore be replaced by the phrases "position and orientation," and vice versa.

[0026] Within the deflection range, the limit switch and vibration damper exerts no force on the second component, allowing it to move freely. Outside the permissible deflection range, the limit switch and vibration damper mechanically blocks the second component relative to the first, preventing any relative movement between the components. This can be achieved, for example, by the limit switch and vibration damper engaging with either the first or second component when the deflection limit is reached, thus preventing further movement of the second component relative to the first.

[0027] A "natural mode" or "normal mode" is a specific movement of an oscillating system, predominant in the second component. This is Carl Zeiss SMT GmbH.

[0028] 5

[0029] This refers to those periodic motions in which all components or elements of the system exhibit the same frequency when the system is left to itself after excitation. Such a frequency is called the system's eigenfrequency. The number of different eigenmodes is equal to the number of degrees of freedom of the system.

[0030] The end-stop and vibration damping device, through its mechanical properties, dampens the natural modes of the second component. The end-stop and vibration damping device requires specific parameters to dampen the natural modes. These parameters are the stiffness k, the damping d, and the mass m. These parameters k, d, and m are preferably designed such that the natural frequency co o the end stop and vibration damper device given by

[0031]

[0032] The end stop and vibration damping device operates at approximately 90% of the natural frequency to be damped. This allows the device to effectively dampen the vibrations of the second component and prevent instabilities in a control loop of the second component. The device preferably comprises an elastomeric component possessing the required stiffness and damping properties, and a mass element providing the necessary mass m. The elastomeric component can also contribute to the mass m. The mass element can be a plunger. Furthermore, the mass element can contribute to the stiffness k and the damping d.

[0033] The fact that the limit stop and vibration damping device is "partially" attached to the second component means, in this case, in particular, that at least some components or elements of the limit stop and vibration damping device are mounted or attached to the second component. However, this does not preclude the possibility that the limit stop and vibration damping device may also be completely attached to the second component. This means that all components or elements of the limit stop and vibration damping device may be attached to the second component. It is also possible that some components or elements of the limit stop and vibration damping device are mounted on the first component. Furthermore, it is also possible that components or elements of the limit stop and vibration damping device are part of the first component and / or the second component. Carl Zeiss SMT GmbH

[0034] 6

[0035] According to one embodiment, the end stop and vibration damping device is provided on a side surface of the first component and / or on a side surface of the second component.

[0036] This means, in particular, that the end stop and vibration damping device can be arranged between the first and second components. A gap can be provided between the two side surfaces, within which the end stop and vibration damping device is located. The side surface of the first component and the side surface of the second component are, in particular, each located at the edge of the first and second components, respectively. The side surfaces thus each form an edge of the first or the second component. For example, components or elements of the end stop and vibration damping device can be provided or attached to the side surface of the first component, and further components or elements can be provided or attached to the side surface of the second component.

[0037] According to another embodiment, the end stop and vibration damper device has a plunger attached to the second component and a receiving area attached to the first component, wherein the plunger projects into the receiving area.

[0038] The end stop and vibration damper device can be assigned a symmetry or central axis, with respect to which the device can be essentially rotationally symmetrical. The plunger is, in particular, rod-shaped or web-shaped and can, for example, extend from the side surface of the second component. The plunger can have a circular cross-section, for example. However, the plunger can, in principle, have any cross-sectional geometry. For example, the plunger can have a T-shaped, I-shaped, C-shaped, star-shaped, hexagonal, or triangular cross-sectional geometry. The receiving area can be a recess or cavity machined into the first component. For example, the receiving area can be produced using a subtractive manufacturing process.The recording area is specifically directed towards the aforementioned gap that is provided between the two components.

[0039] According to a further embodiment, the end stop and vibration damper device has an elastomeric part attached to the plunger, which is arranged within the receiving area. Carl Zeiss SMT GmbH

[0040] 7

[0041] In other words, the elastomeric part projects into the receiving area. Specifically, the plunger comprises a first end section connected to the second component, and a second end section facing away from the first end section, to which the elastomeric part is attached. The elastomeric part can, for example, be ring-shaped and surround the plunger. Alternatively, the elastomeric part can also be plate-shaped. The elastomeric part is preferably made of an elastomer. The elastomeric part can be screwed, bonded, or vulcanized to the plunger, for example. The elastomeric part contacts the receiving area when the limit of the deflection range is reached. At this point, the plunger and / or the elastomeric part can be elastically deformed.

[0042] According to another embodiment, the receiving area has an inner surface, wherein the elastomer part contacts the inner surface when a limit of the deflection range is reached.

[0043] For example, when the limit of the deflection range is reached, the elastomer component presses against the inner surface. In this process, the elastomer component can deform elastically. The plunger can also deform elastically. Preferably, however, the plunger does not deform.

[0044] According to another embodiment, the inner surface is at least partially frustoconical.

[0045] The inner surface can also be cylindrical. In this case, the receiving area can be, for example, a bore. Alternatively, the receiving area can also be groove-shaped. In this case, the inner surface is U-shaped or C-shaped. If the receiving area is groove-shaped, several plungers with their elastomeric components can be accommodated in the receiving area.

[0046] According to another embodiment, the end stop and vibration damper device has a plunger attached to the first component and a receiving area attached to the second component, wherein the plunger projects into the receiving area.

[0047] Unlike the previous embodiment of the limit stop and vibration damper device, in this case a part of the limit stop and vibration damper device, namely the plunger, is fixedly mounted to the first component. This plunger projects into the receiving area of ​​the second component. Carl Zeiss SMT GmbH

[0048] 8

[0049] into. The receiving area is in particular part of the end stop and vibration damper device. The receiving area can be a bore or recess incorporated into the second component.

[0050] According to another embodiment, the end stop and vibration damper device has an elastomer part that lines the receiving area, with the plunger projecting into the elastomer part.

[0051] The elastomeric part can, for example, be glued or vulcanized into the receiving area. Alternatively, the elastomeric part can also be screwed into the receiving area. The elastomeric part is thus firmly connected to the second component. The plunger projects into the elastomeric part, which in turn is received in the receiving area.

[0052] According to another embodiment, the elastomer part has an inner surface, wherein the plunger contacts the inner surface when a limit of the deflection range is reached.

[0053] When the plunger contacts the inner surface of the elastomeric part, the elastomeric part preferably deforms elastically. The plunger preferably does not deform upon contact.

[0054] According to another embodiment, the inner surface is at least partially frustoconical.

[0055] The inner surface can alternatively be cylindrical, for example. If the receiving area is groove-shaped, the elastomer part is channel-shaped and has a C-shaped or U-shaped inner surface. In this case, several plungers can be arranged within the elastomer part.

[0056] According to another embodiment, the end stop and vibration damper device has an additional mass that is attached to or embedded in the elastomer part.

[0057] For example, the additive compound can be bonded to the elastomeric part, particularly to its inner surface. The elastomeric part can also be vulcanized to the additive compound. Furthermore, the additive compound can be located within the elastomeric part. In this case, the additive compound can, for example, be bonded to a material from which the elastomeric part is made. Carl Zeiss SMT GmbH

[0058] 9

[0059] It may be encased or enclosed. The additional material could, for example, be a metal plate.

[0060] According to a further embodiment, the end stop and vibration damper device has a plunger attached to the first component and an elastomer part attached to the second component, wherein the plunger contacts the elastomer part when a limit of the deflection range is reached.

[0061] The elastomeric part can, for example, be plate-shaped. In the aforementioned embodiment, preferably at least two end-stop and vibration damping devices are provided, wherein one of the two end-stop and vibration damping devices has an elastomeric part attached to a front face of the second component, and one of the end-stop and vibration damping devices has an elastomeric part arranged on the side surface of the second component. Each of the end-stop and vibration damping devices has a plunger which preferably extends from the side surface of the first component. With this arrangement, it is possible to lock the second component in different degrees of freedom.

[0062] According to a further embodiment, the end stop and vibration damper device has a plunger attached to the second component and an elastomer part attached to the plunger, wherein the elastomer part contacts the first component when a limit of the deflection range is reached.

[0063] Preferably, at least two such end-stop and vibration damping devices are provided in this case, the plungers of which extend from the side surface of the second component. Each plunger has a first end section with which the respective plunger is connected to the second component, and a second end section to which an elastomeric part, as previously mentioned, is attached. When the limit of the deflection range is reached, the elastomeric parts contact the second component, for example, at the front and side surfaces. In this case, too, a locking of different degrees of freedom is possible.

[0064] According to another embodiment, the second component has six degrees of freedom, with the optical system having several endstop and Carl Zeiss SMT GmbH

[0065] 10

[0066] has vibration damping devices, and wherein each of the end stop and vibration damping devices is assigned at least exactly one degree of freedom.

[0067] Each end-stop and vibration damper device can also be assigned multiple degrees of freedom. In particular, the second component—as mentioned previously—has three translational degrees of freedom and three rotational degrees of freedom. For example, all degrees of freedom can be blocked using three such end-stop and vibration damper devices, as long as the respective limit of the deflection range assigned to each end-stop and vibration damper device is reached. In this case, each end-stop and vibration damper device is assigned two degrees of freedom.

[0068] Furthermore, a projection exposure system with such an optical system is proposed.

[0069] The optical system is preferably a projection optic of the projection exposure system. However, the optical system can also be 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.

[0070] 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 term used here should not be interpreted as restricting the number to precisely the stated number of elements. Instead, numerical deviations, both higher and lower, are possible unless otherwise specified.

[0071] The embodiments and features described for the optical system apply accordingly to the proposed projection exposure system and vice versa.

[0072] 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. Carl Zeiss SMT GmbH

[0073] 11

[0074] The person skilled in the art may also add individual aspects as improvements or additions to the respective basic form of the invention.

[0075] Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the embodiments of the invention described below. The invention will now be explained in more detail with reference to preferred embodiments and the accompanying figures.

[0076] Fig. 1 shows a schematic meridional section of a projection exposure system for EUV projection lithography!

[0077] Fig. 2 shows a schematic view of an embodiment of an optical system for the projection exposure system according to Fig. 1;

[0078] Fig. 3 shows a schematic top view of the optical system according to Fig. 2;

[0079] Fig. 4 shows a schematic partial sectional view of another embodiment of an optical system for the projection exposure system according to Fig. 1;

[0080] Fig. 5 shows a schematic partial sectional view of another embodiment of an optical system for the projection exposure system according to Fig. 1;

[0081] Fig. 6 shows a schematic partial sectional view of another embodiment of an optical system for the projection exposure system according to Fig. 1; and

[0082] Fig. 7 shows a schematic partial sectional view of another embodiment of an optical system for the projection exposure system according to Fig. 1.

[0083] 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.

[0084] Fig. 1 shows an embodiment of a projection exposure system 1 (lithography system), in particular an EUV lithography system. One embodiment of an illumination system 2 of the projection exposure system 1 has, in addition to a light or radiation source 3, an illumination optic 4 for illuminating an object field 5 in an object plane 6. In an alternative Carl Zeiss SMT GmbH

[0085] 12

[0086] Alternatively, the light source 3 can be provided as a separate module from the rest of the lighting system 2. In this case, the lighting system 2 does not include the light source 3.

[0087] 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.

[0088] Figure 1 illustrates 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. In Figure 1, the scan direction runs along the y-direction y. The z-direction z runs perpendicular to the object plane 6.

[0089] 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 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.

[0090] 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.

[0091] Light source 3 is an EUV radiation source. Light source 3 emits, in particular, EUV radiation 16, which is also referred to below as useful radiation, illumination radiation, or illumination light. The useful radiation 16 has a wavelength in the range between 5 nm and 30 nm. Light source 3 can be a plasma source, for example, an LPP source (Laser Produced Plasma, plasma generated using a laser) or a DPP source (Gas Discharged Produced Plasma, plasma generated by gas discharge). It can also be a synchrotron-based radiation source. Light source 3 can be a free-electron laser (FEL). Carl Zeiss SMT GmbH

[0092] 13

[0093] 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 (Gl), 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, on the one hand to optimize its reflectivity for the useful radiation and on the other hand to suppress stray light.

[0094] 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.

[0095] 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 a beam-shaping effect in addition to its deflecting function. 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. Only a few of these first facets 21 are shown as examples in Fig. 1.

[0096] The first facets 21 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or semicircular edge contour. The first facets 21 can be designed as planar facets or alternatively as convexly or concavely curved facets.

[0097] As is known, for example, from DE 102008009600 A1, the first facets 21 themselves can each be composed of a multitude of individual mirrors, in particular a multitude of micromirrors. The first facet mirror 20 can in particular be a microelectromechanical system. Carl Zeiss SMT GmbH

[0098] 14

[0099] (MEMS system) be trained. For details, refer to DE 102008009600 Al.

[0100] Between the collector 17 and the deflecting mirror 19, the illumination radiation 16 runs horizontally, i.e. along the y-direction y.

[0101] 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 1614 008 B1, and US 6,573,978.

[0102] 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.

[0103] 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 102008009600 Al in this regard.

[0104] The second facets 23 can have planar or alternatively convex or concave curved reflective surfaces.

[0105] The illumination optics 4 thus form a doubly faceted system. This basic principle is also known as a honeycomb condenser (EnglJ Fly's Eye Integrator).

[0106] 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 102017220586 A1.

[0107] With the aid of the second facet mirror 22, the individual first facets 21 are imaged into the object field 5. The second facet mirror 22 is the last Carl Zeiss SMT GmbH

[0108] 15

[0109] bundle-forming or actually the last mirror for the illumination radiation 16 in the beam path in front of the object field 5.

[0110] 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, normal incidence mirrors) and / or one or two mirrors for grazing incidence (GF mirrors, grazing incidence mirrors).

[0111] In the embodiment shown in Fig. 1, the lighting optics 4 has exactly three mirrors after the collector 17, namely the deflecting mirror 19, the first faceted mirror 20 and the second faceted mirror 22.

[0112] 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.

[0113] The imaging 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 imaging.

[0114] 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.

[0115] In the example shown in Fig. 1, the projection optics 10 comprises 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 double-obscured optic. The penultimate mirror M5 and the last mirror M6 each have a transmission 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. Carl Zeiss SMT GmbH

[0116] 16

[0117] 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.

[0118] 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.

[0119] The projection optics 10 can be anamorphic. In particular, they have different image scales βx, βy in the x and y directions. The two image scales βx, βy of the projection optics 10 are preferably (βx, βy) = (+ / - 0.25, + / - 0.125). A positive image scale β indicates an image without image inversion. A negative sign for the image scale β indicates an image with image inversion.

[0120] 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.

[0121] The projection optics 10 lead to a reduction of 8H in the y-direction y, that is, in the scan direction.

[0122] 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.

[0123] 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 A.

[0124] Each of the second facets 23 is exactly one of the first facets 21 to form one lighting channel for illuminating the object field. Carl Zeiss SMT GmbH

[0125] 17

[0126] 5 assigned. This can result in illumination according to Köhler's principle. The far field is divided into a multitude 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 each of them.

[0127] The first facets 21 are each superimposed on an associated second facet 23 to illuminate the object field 5 on the reticulum 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.

[0128] The illumination of the entrance pupil of the projection optics 10 can be geometrically defined by the arrangement of 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.

[0129] 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.

[0130] 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.

[0131] The projection optics 10 can, in particular, have a homocentric entrance pupil. This can be accessible. It can also be inaccessible.

[0132] 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 spatial space. In particular, this surface exhibits a finite curvature. Carl Zeiss SMT GmbH

[0133] 18

[0134] 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 then be used to account for the different positions of the tangential and sagittal entrance pupils.

[0135] In the arrangement of the components of the illumination optics 4 shown in Fig. 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.

[0136] Fig. 2 shows a schematic view of an embodiment of an optical system 100 for the projection exposure system 1. Fig. 3 shows a schematic top view of the optical system 100. Reference is made hereafter to Figs. 2 and 3 simultaneously.

[0137] The optical system 100 can be a projection optic 10, as previously described, or part of such a projection optic 10. Therefore, the optical system 100 can also be referred to as a projection optic. However, the optical system 100 can also be an illumination system 2, as previously described, or part of such an illumination system 2. Therefore, the optical system 100 can alternatively be referred to as an illumination system. In the following, however, it will be assumed that the optical system 100 is a projection optic 10 or part of such a projection optic 10. The optical system 100 is suitable for EUV lithography. However, the optical system 100 can also be suitable for DUV lithography.

[0138] The optical system 100 can comprise several optical elements 102, of which only one is shown in Figures 2 and 3. Therefore, only one optical element 102 will be discussed below. The optical element 102 can be one of the mirrors M1 to M6. The optical element 102 comprises a substrate 104 and an optically effective surface 106, for example, a mirror surface. The substrate 104 can also be referred to as the mirror substrate. The substrate 104 can comprise glass, ceramic, glass-ceramic, or other suitable materials. Carl Zeiss SMT GmbH

[0139] 19

[0140] The optically effective surface 106 is provided on a front face 108 of the optical element 102, in particular of the substrate 104. The optically effective surface 106 can be realized by means of a coating applied to the front face 108. The optically effective surface 106 is a mirror surface. The optically effective surface 106 is suitable for reflecting illumination radiation 16, in particular EUV radiation, during operation of the optical system 100. The optically effective surface 106 can have an oval or elliptical geometry in the top view shown in Fig. 3. The optical element 102 or the substrate 104 can have a triangular geometry. In principle, however, the geometry is arbitrary.

[0141] The optical element 102 has a back surface 110 facing away from the optically effective surface 106 or the front surface 108. The back surface 110 has no defined optical properties. In particular, this means that the back surface 110 is not a mirror surface and therefore has no reflective properties.

[0142] Several mirror bushings 112, 114, 116 are provided on the rear side 110. A first mirror bushing 112, a second mirror bushing 114, and a third mirror bushing 116 are provided. In other words, the optical element 102 comprises exactly three mirror bushings 112, 114, 116. The mirror bushings 112, 114, 116 can be geometrically identical. The mirror bushings 112, 114, 116 are cylindrical and, in the orientation shown in Fig. 2, extend from the underside of the rear side 110. The mirror bushings 112, 114, 116 form the vertices of an imaginary triangle.

[0143] The optical element 102 or the optically effective surface 106 has six degrees of freedom, namely three translational degrees of freedom along a first spatial direction or x-direction x, a second spatial direction or y-direction y, and a third spatial direction or z-direction z, as well as three rotational degrees of freedom about the x-direction x, the y-direction y, and the z-direction z. That is, the position and orientation of the optical element 102 or the optically effective surface 106 can be determined or described using the six degrees of freedom.

[0144] The "position" of the optical element 102 or the optically effective surface 106 refers in particular to its coordinates or the coordinates of a measuring point provided on the optical element 102 with respect to the x-direction x, the y-direction y and the z-direction z. The "orientation" of the optical element 102 or the optically effective surface 106 Carl Zeiss SMT GmbH

[0145] 20

[0146] This refers in particular to its or their tilting with respect to the three directions x, y, z. That is, the optical element 102 or the optically effective surface 106 can be tilted about the x-direction x, the y-direction y and / or the z-direction z.

[0147] This results in six degrees of freedom for the position and orientation of the optical element 102 or the optically effective surface 106. A "position" of the optical element 102 or the optically effective surface 106 encompasses both its position and its orientation. The term "position" can therefore be replaced by the phrase "position and orientation" and vice versa.

[0148] Figure 2 shows the actual position IL of the optical element 102 with solid lines and the desired position SL of the optical element 102 with dashed lines and the reference symbol 102'. The optical element 102 can be moved from its actual position IL to the desired position SL and vice versa. For example, the optical element 102 in the desired position SL fulfills certain optical specifications or requirements that the optical element 102 in the actual position IL does not fulfill.

[0149] To move the optical element 102 from its actual position IL to its target position SL, the optical system 100 includes an adjustment device 118. The adjustment device 118 is configured to adjust the optical element 102. In this context, "adjusting," "deflection," or "alignment" refers specifically to changing the position of the optical element 102. For example, the optical element 102 can be moved from its actual position IL to its target position SL and vice versa using the adjustment device 118. The adjustment, deflection, or alignment of the optical element 102 can thus be performed in all six degrees of freedom mentioned above using the adjustment device 118.

[0150] The adjustment device 118 comprises several actuator assemblies 120, 122, 124, which are shown only in a highly schematic form in Fig. 2. The actuator assemblies 120, 122, 124 can also be referred to as adjusting element assemblies or as bipods. Each mirror socket 112, 114, 116 is assigned an actuator assembly 120, 122, 124. This means, in particular, that exactly three actuator assemblies 120, 122, 124 are provided. With the three actuator assemblies 120, 122, 124, adjustment of the optical element 102 in all six degrees of freedom is possible. Carl Zeiss SMT GmbH

[0151] 21

[0152] The first mirror socket 112 is assigned a first actuator assembly 120. The second mirror socket 114 is assigned a second actuator assembly 122. The third mirror socket 116 is assigned a third actuator assembly 124. The actuator assemblies 120, 122, and 124 are identical in construction. Therefore, only the first actuator assembly 120 and the first mirror socket 112 will be discussed below; these will be referred to simply as actuator assembly 120 and mirror socket 112, respectively. All subsequent explanations concerning actuator assembly 120 are applicable to actuator assemblies 122 and 124, and vice versa.

[0153] The actuator assembly 120 is coupled to the mirror socket 112 via a connection point 126. Furthermore, the actuator assembly 120 is coupled to a fixed world 132 via two additional connection points 128 and 130. The fixed world 132 can be a force frame or another immobile structure.

[0154] The actuator arrangement 120 comprises two actuators 134, 136, in particular a first actuator 134 and a second actuator 136. The six degrees of freedom of the optical element 102 can be adjusted using all actuators 134, 136 of all actuator arrangements 120, 122, 124. The actuators 134, 136 can also be referred to as adjusting elements or actuators.

[0155] Both actuators 134 and 136 are connected to the mirror socket 112 at connection point 126. Furthermore, actuators 134 and 136 are connected to the fixed world 132 via connection points 128 and 130. Actuators 134 and 136 can be controlled by a control unit 138 of the adjustment device 118 to adjust the optical element 102. All actuators 134 and 136 of all actuator arrangements 120, 122, and 124 are operatively connected to the control unit 138, so that the control unit 138 can adjust the optical element 102 in all six degrees of freedom by appropriately controlling the actuators 134 and 136. This can be done based on sensor signals from a sensor system not shown, which can detect the actual position IL and the target position SL of the optical element 102.

[0156] The optical element 102 is accordingly mounted on the actuator assemblies 120, 122, 124 or on the actuators 134, 136. To minimize heat generation in the actuators 134, 136, the weight of the optical element 102 is generally absorbed by a weight compensator (not shown). Each actuator assembly 120, 122, 124 is assigned such a weight compensator. Carl Zeiss SMT GmbH

[0157] 22

[0158] It is subsequently assumed that the optical system 100 is a projection optic 10 as previously described and comprises several optical elements 102, in particular mirrors M1 to M6. A central component of the optical system 100 are the high-precision optical elements 102, in particular mirrors M1 to M6, which reflect, focus, and direct the illumination radiation 16, in particular EUV radiation.

[0159] To ensure the proper functioning of these optical elements 102 and to protect them from damage, so-called end stops can be used, which limit the maximum deflection of the optical elements 102 along the x, y, z directions and / or around the x, y, z directions. Without this limitation, the optical elements 102 could be damaged by excessive deflections, which would lead to costly repairs and production downtime.

[0160] Such end stops typically comprise a plunger and an elastomer tip, which is, for example, designed as a ring. The plunger is attached to a support structure outside the respective optical element 102, for example, a Mirror Support Frame (MSF), a Force Frame (FFr), or a Sensor Frame (SFr), and is received with clearance in a recess provided on the optical element 102. This recess may be machined into the substrate 104. This design locks certain degrees of freedom of the optical element 102 in the event of excessive movement of the optical element 102, thereby limiting its maximum amplitude of movement.

[0161] The position control of the optical elements 102 is achieved – as previously mentioned – in up to six degrees of freedom. Translation along the x, y, z directions and rotation around these directions are both possible. The complex control required for this necessitates effective damping of the eigenmodes of the optical elements 102 to avoid amplitude amplification and the associated instability in the control loop.

[0162] The attenuation of the eigenmodes of the optical elements 102 can be achieved in two main ways. Firstly, control-based attenuation using notch filters is possible. These notch filters are specifically designed to suppress certain frequencies, thereby selectively attenuating the eigenmodes of the optical elements 102. However, this also reduces the possible Carl Zeiss SMT GmbH

[0163] 23

[0164] Bandwidth achievable through regulation. Therefore, performance is optimized against robustness.

[0165] On the other hand, passive damping is possible using so-called vibration dampers or tuned mass dampers (TMDs). Such vibration dampers can be mounted directly on the optical elements 102 and, due to their mechanical properties, dampen the natural modes. Vibration dampers are particularly effective because they operate passively and do not require additional control. Therefore, they are also "performance-neutral" and do not limit the bandwidth.

[0166] Such a vibration damper requires specific parameters to dampen the natural modes. These parameters are the stiffness k, the damping d, and the mass m. These parameters k, d, and m are calculated such that the natural frequency <D0des Schwingungstilger gegeben durch

[0167]

[0168] at approximately 90% of the natural frequency to be damped. This allows the vibration damper to effectively dampen the vibrations and prevent instabilities in the control loop. Such a vibration damper typically comprises an elastomer that exhibits the required stiffness and damping properties, as well as a metal element that provides the necessary mass m.

[0169] However, a challenge arises when small optical elements 102 or optical elements 102 with specific requirements for the placement of attachments are used. In these cases, ideal positions for end stops and vibration dampers can overlap, which can lead to installation space conflicts. These installation space conflicts complicate the mounting of the components in the form of end stops and vibration dampers and impair the efficiency of the damping and deflection limitation of the optical elements 102. This needs to be improved.

[0170] Fig. 4 shows a schematic partial sectional view of another embodiment of an optical system 200A for the projection exposure system 1.

[0171] The optical system 200A can be identical to the optical system 100. This means that all previous statements concerning the optical system Carl Zeiss SMT GmbH are valid.

[0172] 24

[0173] 100 applies to the optical system 200A and all subsequent statements concerning the optical system 200A are applicable to the optical system 100. In other words, the optical system 200A is a projection optic 10 as previously described or part of a projection optic 10 as previously mentioned.

[0174] The optical system 200A comprises a first component 202 and a second component 204. The first component 202 can be a mirror support frame, a support frame, or a sensor frame. The second component 204 can be an optical element 102 as previously described, in particular a mirror M1 to M6. However, the second component 204 can also be any other component of the projection optics 10. For example, it is possible that the first component 202 is a support frame and the second component 204 is a sensor frame.

[0175] The second component 204 is preferably mounted using a weight-compensating bearing, so that the second component 204 can move without force relative to the first component 202. In other words, only the second component 204 is deflectable. The first component 202 is fixed and can be connected to the previously mentioned fixed world 132 (not shown).

[0176] The second component 204 has a certain actuated range, deflection range, or actuation range relative to the first component 202, within the limits of which the second component 204 can move relative to the first component 202. In particular, the second component 204 can be deflected relative to the first component 202 within the limits of the deflection range. This deflection or adjustment can be carried out with the aid of an adjustment device 118 (not shown) as previously described. The second component 204 can have six degrees of freedom, as previously explained with reference to the optical element 102: three translational degrees of freedom each along the x-direction x, the y-direction y, and the z-direction z, and three rotational degrees of freedom or tilting degrees of freedom about the x-direction x, the y-direction y, and the z-direction z.

[0177] To limit the movement amplitude of the second component 204, for example in the event of a shock, relative to the first component 202, a combined end stop and vibration damper device 206A can be provided. The end stop and vibration damper device 206A combines the functionalities of an end stop and a vibration damper, as described previously. This makes it possible to avoid the previously described space constraints and to increase the damping efficiency of the Carl Zeiss SMT GmbH

[0178] 25

[0179] to increase the second component 204. In other words, the end-stop and vibration damper device 206A combines the mechanical properties of an end stop and a vibration damper, thus enabling a space-saving solution.

[0180] The end-stop and vibration damping device 206A is not attached to the stationary first component 202, but to the second component 204, which is movable relative to the stationary first component 202. The second component 204 may have, for example, an optically effective surface 106 (not shown) on a front face 208, as previously described with reference to the optical element 102, in particular a mirror surface suitable for reflecting illumination radiation 16, especially EUV radiation. The end-stop and vibration damping device 206A is attached to a side surface 210 of the second component 204, which has no defined optical properties. The side surface 210 may point away from the front face 208. However, this is not mandatory. The front face 208 and the side surface 210 may also point in the same direction.

[0181] The end stop and vibration damper device 206A can be assigned a symmetry or central axis 212, with which the end stop and vibration damper device 206A can be rotationally symmetrical. However, this is not mandatory.

[0182] The end-stop and vibration damping device 206A has a rod-shaped plunger 214, which is rigidly connected to the second component 204, in particular to the side surface 210. The plunger 214 is made of a metallic material, such as a stainless steel alloy. The plunger 214 can be rotationally symmetrical about the central axis 212. In this case, the plunger 214 has a circular cross-sectional geometry. However, the plunger 214 can also have a T-shaped, I-shaped, C-shaped, rectangular, star-shaped, hexagonal, or triangular cross-sectional geometry. In principle, the plunger 214 can have any cross-sectional geometry.

[0183] The plunger 214 is spring-elastic and deformable. This means that the plunger 214 can be moved from an undeformed state to a deformed state by applying an external force. When this force is removed, the plunger 214 deforms itself back from the deformed state to the undeformed state. Carl Zeiss SMT GmbH

[0184] 26

[0185] The plunger 214 projects into a gap 216 provided between the two components 202 and 204. The plunger 214 has a first end section 218, which is connected to the second component 204, and a second end section 220, which faces away from the first end section 218. An elastomeric part 222 is attached to the second end section 220. The elastomeric part 222 is made of an elastomer. The elastomeric part 222 can be screwed, glued, or vulcanized to the plunger 214. The elastomeric part 222 can be ring-shaped around the plunger 214. The elastomeric part 222 can also be plate-shaped. The elastomeric part 222 can have any desired geometry. The elastomeric part 222 preferably has a larger cross-sectional area than the plunger 214 when viewed perpendicular to the central axis 212.

[0186] The plunger 214, together with the elastomeric part 222, extends into a receiving area 224 that is integrated into the first component 202. The receiving area 224 can be integrated into a side surface 226 of the first component 202 opposite the side surface 210. The receiving area 224 can be part of the end-stop and vibration damping device 206A. However, this is not mandatory.

[0187] The receiving area 224 can be a bore, a recess, a cutout, or the like. The receiving area 224 can be cylindrical. However, the receiving area 224 can also be conical or frustoconical, as shown in Fig. 4. The receiving area 224 can, for example, also be groove-shaped and extend along the x-direction x. In the latter case, several plungers 214 with several elastomeric parts 222 can be received in the receiving area 224.

[0188] The receiving area 224 has an inner surface 228 facing the elastomeric part 222. A gap 230, extending around the elastomeric part 222, is provided between the inner surface 228 and the elastomeric part 222. The elastomeric part 222 therefore does not initially contact the inner surface 228. The gap 230 allows the elastomeric part 222 to deflect radially with respect to the central axis 212 within the receiving area 224.

[0189] The plunger 214, together with the elastomeric part 222, can move into the receiving area 224 along the central axis 212 or against the y-direction y, thereby reducing the gap 230 due to the conical geometry of the receiving area 224. The gap 230 limits the movement of the plunger 214, together with the elastomeric part 222, within the receiving area 224. Carl Zeiss SMT GmbH

[0190] 27

[0191] in the x-direction x and in the z-direction z, by the elastomer part 222 coming into contact with the inner surface 228 when there is sufficient deflection.

[0192] Thus, the gap 230 allows a slight movement of the plunger 214, including the elastomeric part 222, relative to the first component 202 in the x-direction x and in the z-direction z, thereby defining the actuation range of the second component 204 relative to the first component 202. The aforementioned possible radial movement of the plunger 214, including the elastomeric part 222, relative to the receiving area 224 allows actuation of the second component 204 relative to the first component 202 within the actuation range. Outside the actuation range, the end stop and vibration damping device 206A blocks any deflection of the second component 204 relative to the first component 202, since the elastomeric part 222 is in contact with the inner surface 228.

[0193] Preferably, at least three end-stop and vibration damping devices 206A are provided. Each of the end-stop and vibration damping devices 206A allows translational movement along one of the directions x, y, z and two minor translational movements relative to the other two directions x, y, z until the elastomeric part 222 contacts the inner surface 228. When a limit of the actuation range is reached, the elastomeric part 222 contacts the inner surface 228, thus blocking or preventing further deflection or actuation of the second component 204 relative to the first component 202.

[0194] The previously described approach of the end-stop and vibration damper device 206A essentially consists of interchanging the end stop and the recess – as previously explained with reference to the optical system 100 and the optical element 102. This means that the end stop is mounted on the optical element 102, while the recess is located outside the optical element 102, namely on the mirror support frame, the support frame, or the sensor frame. This reversal allows the end-stop and vibration damper device 206A to be designed to act not only as a motion limiter but also as a vibration damper.

[0195] Fig. 5 shows a schematic partial sectional view of another embodiment of an optical system 200B for the projection exposure system 1.

[0196] All previous statements concerning the optical system 200A are correspondingly applicable to the optical system 200B and vice versa. Carl Zeiss SMT GmbH

[0197] 28

[0198] System 200B differs from optical system 200A by a further embodiment of an end-stop and vibration damper device 206B. However, this does not preclude the previously described optical system 200A from also having an end-stop and vibration damper device 206B as described below. Furthermore, optical system 200B may also have an end-stop and vibration damper device 206A as described above.

[0199] The optical system 200B has two components 202 and 204, as previously described. The end-stop and vibration damper device 206B is associated with a symmetry or central axis 232, about which the end-stop and vibration damper device 206B may be rotationally symmetrical. However, this is not mandatory. The end-stop and vibration damper device 206B includes a plunger 234. All previous descriptions concerning the plunger 214 also apply to the plunger 234. However, the plunger 234 is not connected to the second component 204, but to the first component 202. The plunger 234 has a first end section 236, which is connected to the first component 202, and a second end section 238, which points away from the first end section 236. The plunger 234 extends into the gap 216 provided between the two components 202, 204.

[0200] The second component 204, in particular its side surface 210, has a receiving area 240 for receiving the plunger 234, especially the second end section 238. The receiving area 240 can be a bore, a recess, a cutout, or the like. The receiving area 240 can be cylindrical. However, the receiving area 240 can also be conical or frustoconical, as shown in Fig. 5. The receiving area 240 can also be groove-shaped, for example, and extend along the x-direction x. In the latter case, several plungers 234 can be received in the receiving area 240.

[0201] An elastomeric part 242 can be arranged within the receiving area 240. The elastomeric part 242 can be screwed to the second component 204, glued into the receiving area 240, or vulcanized to it. Unlike the elastomeric part 222, the elastomeric part 242 is not connected to the plunger 234. The elastomeric part 242 is made of an elastomer. The elastomeric part 242 has a frustoconical or conical geometry. The elastomeric part 242 can be rotationally symmetrical about the central axis 232. The elastomeric part 242 is part of the end-stop and vibration damper device 206B. Carl Zeiss SMT GmbH

[0202] 29

[0203] The elastomeric part 242 has an inner surface 244 facing the plunger 234. The inner surface 244 has a frustoconical or conical geometry. A gap 246, circumferential to the plunger 234, is provided between the inner surface 244 and the plunger 234, in particular the second end section 238 of the plunger 234. The plunger 234 therefore does not initially contact the inner surface 244. The gap 246 allows the plunger 234 to deflect radially within the elastomeric part 242 with respect to the central axis 232.

[0204] The plunger 234 can move into the elastomeric part 242 along the central axis 232 or in the opposite direction y, thereby reducing the gap 246 due to the conical geometry of the elastomeric part 242. However, the first component 202 remains stationary, while the second component 204 moves relative to the first component 202. The gap 246 limits the movement of the elastomeric part 242, including the second component 204, relative to the plunger 234 in the x-direction x and in the z-direction z, by ensuring that the plunger 234 comes into contact with the inner surface 244 when deflected sufficiently.

[0205] The end-stop and vibration damping device 206B can further comprise an additional mass 248, which is embedded in the elastomer part 242 or attached to the inner surface 244. The additional mass 248 can, for example, be a metal plate. The damping properties of the end-stop and vibration damping device 206B can be improved with the aid of the additional mass 248.

[0206] In summary, unlike in the optical system 200A, the plunger 234 remains positioned outside the movable second component 204, namely on the first component 202. The elastomeric part 242, together with the additional mass 248, is placed in the specially provided receiving area 240 of the second component 204. Specifically, the receiving area 240 is lined with the elastomeric part 242.

[0207] This design divides the end-stop and vibration damping device 206B between the two components 202 and 204. The elastomeric part 242, with its optional additional mass 248, is positioned directly on or attached to the second component 204, while the plunger 234 is mounted on the stationary first component 202. This arrangement not only enables optimal use of the vibration damping effect on or at the second component 204, but also ensures that the plunger 234, which can be designed to withstand high forces, can be securely and effectively rigidly attached to the first component 202, for example, by means of a screw connection. (Carl Zeiss SMT GmbH)

[0208] 30

[0209] which would only be possible with greater effort on or at the second component 204.

[0210] Fig. 6 shows a schematic partial sectional view of another embodiment of an optical system 200C for the projection exposure system 1.

[0211] All previous statements concerning the different embodiments of optical system 200A, 200B are applicable accordingly to optical system 200C and vice versa. Optical system 200C differs from the previously described embodiments of optical system 200A, 200B by further embodiments of end-stop and vibration damping devices 206C, 206D. However, this does not preclude the previously described optical system 200A, 200B from also having end-stop and vibration damping devices 206C, 206D as described below. Furthermore, optical system 200C may also have end-stop and vibration damping devices 206A, 206B as described above.

[0212] The optical system 200C comprises a first end-stop and vibration damper device 206C and a second end-stop and vibration damper device 206D, which limit different degrees of freedom of the second component 204. The first end-stop and vibration damper device 206C limits one degree of freedom of the second component 204 along the z-direction z, whereas the second end-stop and vibration damper device 206D limits one degree of freedom along the y-direction y.

[0213] The first end-stop and vibration damping device 206C comprises a symmetry or central axis 250 and a plunger 252, which may be rotationally symmetrical about the central axis 250. All previous descriptions concerning the plunger 214 are applicable to the plunger 252. The plunger 252 comprises a first end section 254, which is rigidly connected to the first component 202, in particular to the side surface 226 of the first component 202, and a second end section 256, which points away from the first end section 254.

[0214] The first end-stop and vibration damping device 206C further comprises an elastomeric part 258 attached to the second component 204, in particular to the front surface 208 of the second component 204. For example, the elastomeric part 258 can be screwed, bonded, or vulcanized to the front surface 208. If an optically effective surface 106 (not shown) as previously mentioned is provided on the front surface 208, the elastomeric part 258 can be positioned next to the optically effective surface 106. Carl Zeiss SMT GmbH

[0215] 31

[0216] An optional additional mass 260 can be embedded in the elastomeric part 258. The additional mass 260 can also be attached to the outside of the elastomeric part 258. The additional mass 260 can be a metal plate. When the second component 204 is actuated or deflected relative to the first component 202 in the z-direction z, the plunger 252 can contact the elastomeric part 258 with its second end section 256, thus blocking further movement of the second component 204 relative to the first component 202.

[0217] The second end-stop and vibration damping device 206D also comprises a symmetry or central axis 262 and a plunger 264, which can be rotationally symmetrical about the central axis 262. The central axes 250 and 262 can run parallel to each other. All previous descriptions concerning the plunger 214 are applicable to the plunger 264. The plunger 264 comprises a first end section 266, which is rigidly connected to the first component 202, in particular to the side surface 226 of the first component 202, and a second end section 268, which points away from the first end section 266.

[0218] The second end-stop and vibration damper device 206D further comprises an elastomeric part 270 which is attached to the second component 204, in particular to the side surface 210 of the second component 204. For example, the elastomeric part 270 can be screwed, glued or vulcanized to the side surface 210.

[0219] An optional additional mass 272 can be embedded in the elastomeric part 270. The additional mass 272 can also be attached to the outside of the elastomeric part 270. The additional mass 272 can be a metal plate. When the second component 204 is actuated or deflected relative to the first component 202 in the y-direction y, the plunger 264 can contact the end face of the elastomeric part 270 with its second end section 268, thus blocking further movement of the second component 204 relative to the first component 202.

[0220] Fig. 7 shows a schematic partial sectional view of another embodiment of an optical system 200D for the projection exposure system 1.

[0221] All previous statements concerning the different embodiments of the optical system 200A, 200B, 200C are applicable accordingly to the optical system 200D and vice versa. The optical system 200D differs from the previously described embodiments of the optical system. Carl Zeiss SMT GmbH

[0222] 32

[0223] 200A, 200B, 200C by further embodiments of end-stop and vibration damping devices 206E, 206F. However, this does not preclude the previously described optical system 200A, 200B, 200C from also having end-stop and vibration damping devices 206E, 206F as described below. Furthermore, the optical system 200D can also have end-stop and vibration damping devices 206A, 206B, 206C, 206D as described above.

[0224] The optical system 200D has a first end-stop and vibration damper device 206E and a second end-stop and vibration damper device 206F, which limit different degrees of freedom of the second component 204. The first end-stop and vibration damper device 206E limits one degree of freedom of the second component 204 along the z-direction z, whereas the second end-stop and vibration damper device 206F limits one degree of freedom along the y-direction y.

[0225] The first end-stop and vibration damping device 206E comprises a symmetry or central axis 274 and a plunger 276, which can be rotationally symmetrical about the central axis 274. All previous descriptions concerning the plunger 214 are applicable to the plunger 276. The plunger 276 comprises a first end section 278, which is rigidly connected to the second component 204, in particular to the side surface 210 of the second component 204, and a second end section 280, which points away from the first end section 278.

[0226] The first end-stop and vibration damping device 206E further comprises an elastomeric part 282, which is attached at the end of the plunger 276, in particular at the second end section 280. The elastomeric part 282 can be ring-shaped or plate-shaped. The elastomeric part 282 can be rotationally symmetrical about the central axis 274. Upon actuation or deflection of the second component 204 relative to the first component 202 in the z-direction z, the elastomeric part 282 can contact the first component 202 at a front face 284, thus blocking further movement of the second component 204 relative to the first component 202.

[0227] The second end-stop and vibration damping device 206F also comprises a symmetry or central axis 286 and a plunger 288, which can be rotationally symmetrical about the central axis 286. The central axes 274 and 286 can be oriented parallel to each other. All previous descriptions concerning the plunger 214 are applicable to the plunger 288. The plunger 288 comprises a first end section 290, which is fixedly connected to the second component 204. Carl Zeiss SMT GmbH

[0228] 33

[0229] in particular with the side surface 210 of the second component 204, and a second end section 292, which points away from the first end section 290.

[0230] The second end-stop and vibration damping device 206F further comprises an elastomeric part 294, which is attached at the end of the plunger 288, in particular at the second end section 292. The elastomeric part 294 can be ring-shaped or plate-shaped. The elastomeric part 294 can be rotationally symmetrical about the central axis 286. Upon actuation or deflection of the second component 204 relative to the first component 202 in the y-direction y, the elastomeric part 294 can contact the first component 202 at the side surface 226, thus blocking further movement of the second component 204 relative to the first component 202.

[0231] The different embodiments of the end-stop and vibration damping device 206A, 206B, 206C, 206D, 206E, 206F can assume various configurations and are particularly effective when attached to locations on the second component 204 where large movements occur in the natural mode to be damped. This means that the end-stop and vibration damping device 206A, 206B, 206C, 206D, 206E, 206F should be positioned in or as close as possible to the antinodes of the respective natural modes. Since the first eigenmodes typically exhibit high amplitudes at the edges of the second component 204, these positions are ideally suited for the end-stop and vibration damper device 206A, 206B, 206C, 206D, 206E, 206F.Since, from a kinematic point of view, the edges of the second component 204 always travel the greatest distance during a rigid body movement, for this reason too, a positioning of the end stop and vibration damping devices 206A, 206B, 206C, 206D, 206E, 206F at the edges or on the side surface 210 of the second component 204 is preferred.

[0232] By combining the functions of end stops and vibration dampers in a single component, namely the end stop and vibration damper devices 206A, 206B, 206C, 206D, 206E, and 206F, space constraints can be effectively resolved, damping efficiency maximized, and the structural integrity of the second component 204 ensured. This can contribute to improving the performance and reliability of the projection lighting system 1. Furthermore, integrating both functions into one component reduces assembly effort, thereby lowering production costs and simplifying maintenance. Carl Zeiss SMT GmbH

[0233] 34

[0234] Furthermore, this solution allows for a more flexible design of the second component 204 and its associated parts, as less space is required for separate damping and limiting elements. This can lead to more compact and lighter designs, which in turn has a positive impact on assembly effort and production costs. In summary, the combination of end stops and vibration dampers in a single component offers an effective solution to space constraints. This solution provides significant advantages in terms of installation space requirements, performance, production costs, and ease of maintenance.

[0235] The endstop and vibration damping devices 206A, 206B, 206C, 206D, 206E, 206F can be used for all structures and components in the DUV, VUV, and EUV ranges that require both endstops and vibration dampers. Typical examples within projection optics 10 are lenses and mirrors, but also the supporting structures themselves. The endstop and vibration damping devices 206A, 206B, 206C, 206D, 206E, 206F are particularly useful for the application of so-called wedge mirrors, which, due to their specific shape and positioning within projection optics 10, pose particular challenges to the available installation space.

[0236] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. Carl Zeiss SMT GmbH

[0237] 35 REFERENCE SIGN LIST

[0238] 1 Projection exposure system 2 Lighting system

[0239] 3 light source

[0240] 4 B lighting optics

[0241] 5 object field

[0242] 6 Object level

[0243] 7 reticles

[0244] 8 label holders

[0245] 9 Reticle displacement drive 10 Projection optics

[0246] 11 Image field

[0247] 12 Image plane

[0248] 13 wafers

[0249] 14 wafer holders

[0250] 15 W wafer transfer drive 16 B lighting radiation

[0251] 17 Collector

[0252] 18 Intermediate focus plane

[0253] 19 deflecting mirrors

[0254] 20 first faceted mirror

[0255] 21 first facet

[0256] 22 second faceted mirror

[0257] 23 second facet

[0258] 100 optical system

[0259] 102 optical element

[0260] 102' optical element

[0261] 104 Substrat

[0262] 106 optically effective area 108 front

[0263] 110 reverse

[0264] 112 Mirror socket

[0265] 114 Mirror socket

[0266] 116 Mirror socket

[0267] 118 Adjustment device

[0268] 120 actuator arrangement

[0269] 122 Actuator arrangement

[0270] 124 Actuator arrangement

[0271] 126 Connection gsp pointCarl Zeiss SMT GmbH

[0272] 36

[0273] 128 Connection point

[0274] 130 Connection point

[0275] 132 solid world

[0276] 134 Actuator

[0277] 136 Actuator

[0278] 138 Control and regulating unit

[0279] 200A optical system

[0280] 200B optical system

[0281] 200C optical system

[0282] 200D optical system

[0283] 202 Component

[0284] 204 Component

[0285] 206A End stop and vibration damper device 206B End stop and vibration damper device 206C End stop and vibration damper device 206D End stop and vibration damper device 206E End stop and vibration damper device 206F End stop and vibration damper device 208 Front

[0286] 210 side area

[0287] 212 Central axis

[0288] 214 pestles

[0289] 216 gap

[0290] 218 Final section

[0291] 220 End section

[0292] 222 Elastomer part

[0293] 224 Recording area

[0294] 226 side area

[0295] 228 interior surface area

[0296] 230 gap

[0297] 232 Central axis

[0298] 234 pestles

[0299] 236 End section

[0300] 238 Final section

[0301] 240 recording area

[0302] 242 Elastomer part

[0303] 244 interior surface area

[0304] 246 gap

[0305] 248 additional mass

[0306] 250 Central axis Carl Zeiss SMT GmbH

[0307] 37

[0308] 252 pestles

[0309] 254 End section 256 End section 258 Elastomer part 260 Additional mass 262 Central axis 264 Plunger

[0310] 266 End section 268 End section 270 Elastomer part 272 Additional mass 274 Central axis 276 Plunger

[0311] 278 End section 280 End section 282 Elastomer part 284 Front side 286 Center shaft 288 Plunger

[0312] 290 End section 292 End section 294 Elastomeric part

[0313] IL Current Situation

[0314] SL Target position M1 mirror M2 mirror M3 mirror M4 mirror M5 mirror M6 mirror

[0315] x x-direction y y-direction z z-direction

Claims

Carl Zeiss SMT GmbH 38 PATENT CLAIM 1. Optical system (200A, 200B, 200C, 200D) for a projection exposure system (1), comprising a first component (202), a second component (204), wherein the second component (204) is deflectable within a deflection range relative to the first component (202), and an end-stop and vibration damping device (206A, 206B, 206C, 206D, 206E, 206F) which allows movement of the second component (204) relative to the first component (202) within the deflection range and blocks movement outside the deflection range, and which is configured to dampen eigenmodes of the second component (204), wherein the end stop and vibration damper device (206A, 206B, 206C, 206D, 206E, 206F) is at least partially attached to the second component (204).

2. Optical system according to claim 1, wherein the end stop and vibration damper device (206A, 206B, 206C, 206D, 206E, 206F) is provided on a side surface (226) of the first component (202) and / or on a side surface (210) of the second component (204).

3. Optical system according to claim 1 or 2, wherein the end stop and vibration damper device (206A) has a plunger (214) attached to the second component (204) and a receiving area (224) attached to the first component (202), and wherein the plunger (214) projects into the receiving area (224).

4. Optical system according to claim 3, wherein the end stop and vibration damper device (206A) has an elastomer part (222) attached to the plunger (214) which is arranged within the receiving area (224).

5. Optical system according to claim 4, wherein the receiving area (224) has an inner surface (228), and wherein the elastomeric part (222) contacts the inner surface (228) when a limit of the deflection range is reached.

6. Optical system according to claim 5, wherein the inner surface (228) is at least partially frustoconical. Carl Zeiss SMT GmbH 39 7. Optical system according to claim 1, wherein the end stop and vibration damper device (206B) has a plunger (234) attached to the first component (202) and a receiving area (240) attached to the second component (204), and wherein the plunger (234) projects into the receiving area (240).

8. Optical system according to claim 7, wherein the end stop and vibration damper device (206B) has an elastomer part (242) lining the receiving area (240), and wherein the plunger (234) projects into the elastomer part (242).

9. Optical system according to claim 8, wherein the elastomer part (242) has an inner surface (244), and wherein the plunger (234) contacts the inner surface (244) when a limit of the deflection range is reached.

10. Optical system according to claim 9, wherein the inner surface (244) is at least partially frustoconical.

11. Optical system according to one of claims 8 - 10, wherein the end stop and vibration damper device (206B) has an additional mass (248) which is attached to or embedded in the elastomer part (242).

12. Optical system according to claim 1, wherein the end stop and vibration damper device (206C, 206D) has a plunger (252, 264) attached to the first component (202) and an elastomer part (258, 270) attached to the second component (204), and wherein the plunger (252, 264) contacts the elastomer part (258, 270) when a limit of the deflection range is reached.

13. Optical system according to claim 1, wherein the end stop and vibration damper device (206E, 206F) has a plunger (276, 288) attached to the second component (204) and an elastomer part (282, 294) attached to the plunger (276, 288), and wherein the elastomer part (282, 294) contacts the first component (202) when a limit of the deflection range is reached.

14. Optical system according to any one of claims 1-13, wherein the second component (204) has six degrees of freedom, wherein the optical system (200A, 200B, 200C, 200D) has several limit stop and vibration damper devices (206A, 206B, 206C, 206D, 206E, 206F), and wherein the limit stop and Carl Zeiss SMT GmbH 40 Vibration damping devices (206A, 206B, 206C, 206D, 206E, 206F) are each assigned at least exactly one degree of freedom.

15. Projection exposure system (1) with an optical system (200A, 200B, 200C, 200D) according to one of claims 1 - 14.

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