Bipod, optical system and projection exposure equipment

Abstract

A tripod (202, 202A, 202B, 204, 206) for adjusting an optical element (102, 102 ') of an optical system (100) of a projection exposure apparatus (1), comprising: a mechanism (224) coupled to the optical element (102, 102') to adjust the optical element (102, 102 '); a base portion (218); a first tower column portion (220) extending from the base portion (218); a second pylon portion (222) different from the first pylon portion (220) and also extending from the base portion (218), where the mechanism (224) is disposed between the first pylon portion (220) and the second pylon portion (222), and where the first pylon portion (220) and the second pylon portion (222) are connected to each other and away from the base portion (218) to increase rigidity of the bipod (202, 202A, 202B, 204, 206).

Description

Technical Field

[0001] The invention relates to a bipod for adjusting optical elements of an optical system of a projection exposure apparatus, an optical system having such a bipod, and a projection exposure apparatus having such a bipod and / or such an optical system.

[0002] The entire content of the priority application DE 10 2022 209 902.8 is incorporated herein by reference. Background Art

[0003] Microlithography is used to produce microstructured components, such as integrated circuits. Microlithography processes are performed using a lithography apparatus having an illumination system and a projection system. The image of a mask (reticle) illuminated by the illumination system is projected with the aid of the projection system onto a substrate, such as a silicon wafer, which is coated with a photosensitive layer (photoresist) and is arranged in the image plane of the projection system, in order to transfer the reticle structure to the photosensitive coating of the substrate.

[0004] Driven by the need for smaller structures in the production of integrated circuits, DUV lithography equipment (deep ultraviolet, DUV) is currently being developed, which uses light in the wavelength range between 30 nm and 250 nm, in particular a wavelength of 193 nm. In the case of such DUV lithography equipment, reflective optical units (i.e. mirrors) can be used to replace the refractive optical units (i.e. lens elements) used to date.

[0005] So-called manipulators or bipods can be used to adjust the mirrors of the projection system described above. Three bipods can be assigned to each mirror. With these three bipods, the corresponding mirror can be adjusted in six degrees of freedom. In order to optimize the dynamics of such a system, the highest possible rigidity is required. However, at the same time, the ability to adjust the mirrors should not be restricted. Summary of the invention

[0006] Against this background, an object of the present invention is to provide an improved bipod.

[0007] Therefore, a tripod for adjusting an optical element of an optical system of a projection exposure apparatus is proposed. The tripod comprises a mechanism that can be coupled to the optical element for adjusting the optical element, a base part, a first tower part extending from the base part, a second tower part different from the first tower part and also extending from the base part, wherein the mechanism is arranged between the first tower part and the second tower part, and wherein the first tower part and the second tower part are connected to each other facing away from the base part to increase the rigidity of the tripod.

[0008] Due to the fact that the first tower part and the second tower part are connected to each other, the rigidity of the bipod can be increased. This allows the dynamics of the bipod or the optical system to be optimized. With the dynamic excitation of the bipod, vibrations of the tower parts can be reliably avoided. High-precision adjustments of the optical elements can be made without being affected by vibrations.

[0009] The bipod can also be referred to as a manipulator. A plurality of such bipods can be assigned to the optical system. The optical element is preferably a reflector, in particular a DUV reflector. The optical element has an optically active surface which is configured to reflect the illumination radiation, in particular the DUV radiation. The optically active surface can be a mirror surface. However, the optical element can also be a lens element or the like.

[0010] The optical system can be a projection optical unit of a projection exposure device or a part of a projection optical unit. Therefore, this optical system can also be called a projection optical unit or a projection lens. Alternatively, the optical system can also be an illumination optical unit or a part of such an illumination optical unit. However, it is assumed below that the optical system is a projection optical unit as described above or a part of such a projection optical unit. The optical system can have a plurality of optical elements.

[0011] A coordinate system having a first spatial direction or x-direction, a second spatial direction or y-direction and a third spatial direction or z-direction is assigned to the bipod or the optical system. These spatial directions are arranged perpendicular to one another. The optical element or the optically active surface has six degrees of freedom, specifically three degrees of freedom for translation in the x-direction, the y-direction and the z-direction, and three degrees of freedom for rotation about the x-direction, the y-direction and the z-direction. This means that the position and orientation of the optical element or the optically active surface can be determined or described using the six degrees of freedom.

[0012] The “position” of an optical element or an optically active surface is to be understood as meaning in particular its coordinates or the coordinates of a measuring point arranged on the optical element relative to the x-, y- and z-directions. The “orientation” of an optical element or an optically active surface is to be understood as meaning in particular its inclination relative to the three spatial directions. That is, the optical element or the optically active surface can be tilted relative to the x-, y- and / or z-directions.

[0013] This produces six degrees of freedom of the position and / or orientation of the optical element or optically active surface. The "attitude" of an optical element or optically active surface preferably encompasses both its position and its orientation. Therefore, the term "attitude" can be replaced by the term "position and orientation", and vice versa.

[0014] An “adjustment” or “alignment” of an optical element or an optically active surface is understood to mean in particular a change in the position of the optical element or the optically active surface. For example, the optical element can be moved from an actual position to a target position and vice versa using a bipod or bipods. Thus, an adjustment or alignment of the optical element or the optically active surface can be performed in all six of the above-mentioned degrees of freedom.

[0015] This mechanism can also be referred to as dynamics. The mechanism preferably comprises a coupling element, which can be operatively connected or coupled to the optical element. For example, the optical element has a plurality of reflector seats on its rear side, wherein each reflector seat can be assigned a bipod, which is operatively connected to the corresponding coupling element. For this purpose, an intermediate frame can be provided between one or more bipods and the optical element.

[0016] The mechanism preferably comprises a plurality of lever arms which, as is known, are connected to one another by means of flexures. A "flexure" is generally understood to mean a region of a component, such as a narrowing or thinning of a section, which can achieve a relative movement between two rigid body regions of the component by bending. In this case, the lever arms form rigid body regions which are movably connected to one another by means of flexures.

[0017] The mechanism is configured to convert the stroke of the actuating element into a movement of the coupling element using the aforementioned lever arm and / or flexure. This movement can be converted with a defined transmission ratio. In addition, the mechanism is also suitable for converting the direction of action of the actuating element into a movement of the coupling element with different orientations. The actuating element can be part of the mechanism. A plurality of actuating elements can be provided. Thus, one or more actuating elements are particularly configured to move the coupling element via the aforementioned lever arm and flexure.

[0018] In particular, the mechanism is suitable for moving and / or tilting the coupling element in a translational or linear manner. A purely linear movement, a purely tilting movement, or a combined linear and tilting movement of the coupling element can be achieved. For example, the mechanism can move the coupling element linearly along one of the above-mentioned spatial directions and tilt it around another of the above-mentioned spatial directions.

[0019] For example, the mechanism can move the coupling element linearly along the z-direction and tilt it about the x-direction. The mechanism is thus configured to change or adjust the attitude of the coupling element in two degrees of freedom. By combining a plurality of such bipods to adjust the optical element together, the optical element can thus be moved in all six degrees of freedom and thus its attitude changed.

[0020] The mechanism preferably comprises exactly two actuating elements or actuators. The actuating elements may be piezoelectric elements. The actuating elements are arranged in suitable recesses provided in or on the mechanism. The actuating elements may perform a linear movement which is transferred to the coupling element by means of the mechanism. By means of the aforementioned lever arm and / or flexure, the stroke of the corresponding actuating element may be converted into a movement of the coupling element.

[0021] The base part is in particular rod-shaped or strip-shaped. The base part can preferably extend along one of the aforementioned spatial directions, for example along the y-direction. The base part has a first end part and a second end part. A first tower column part is arranged at the first end part. A second tower column part is arranged at the second end part. The first tower column part and the second tower column part are both arranged perpendicular to the base part. For example, the tower column part extends along the z-direction perpendicular to the y-direction. Therefore, the base part and the tower column part are formed into a U-shaped geometry. For example, the first tower column part, the second tower column part and the mechanism at the top extend out of the base part.

[0022] The base part, the first tower part and the second tower part form an integral component, in particular a component manufactured from a single piece of material. "One piece" or "one component" here in particular means that the base part, the first tower part and the second tower part do not consist of different sub-components, but form a common component. "Made from a single piece of material" here means that the base part, the first tower part and the second tower part are all manufactured from the same material. In particular, the mechanism can also be formed integrally with the base part, in particular as a single piece of material. Thus, the mechanism can be part of the base part or vice versa.

[0023] The fact that the second tower section is "different" from the first tower section specifically means that the first tower section is different from the second tower section and forms two separate parts or regions of the bipod. The first tower section and the second tower section are arranged spaced apart, in particular as viewed in the y-direction, wherein the aforementioned means are arranged between the first tower section and the second tower section.

[0024] For example, the mechanism is arranged between the first tower section and the second tower section, viewed along the y direction. The tower sections can each have a rectangular cross-sectional geometry. The base section can also have a rectangular cross-sectional geometry. In particular, the bipod is in the form of a plate. In particular, "in the form of a plate" is understood here to mean that the geometric extent of the bipod viewed along the y direction and the z direction can be significantly greater than the geometric extent viewed along the x direction.

[0025] A first connection point for connecting the bipod to a fixture, such as a so-called force frame, can be arranged on the first tower part. Thus, a second connection point for connecting to the fixture can be arranged on the second tower part. The connection point can be, for example, a threaded hole. Thus, the tower parts can also be referred to as assembly towers, since they can be used to be connectable or mounted to the fixture. The connection point is arranged at the end or end part of the respective tower part, which faces away from the base part. Thus, the connection point is not arranged on the base part itself, but on the tower part. Thus, viewed in the z-direction, the connection point can be arranged offset upwards relative to the base part.

[0026] As mentioned above, the first tower column part and the second tower column part are both connected to the base part in one piece, in particular in the form of a single piece of material, via a first end or a first end part. The first tower column part and the second tower column part are connected to each other at the second end or the second end part of the respective tower column part facing away from the base part. For this purpose, for example, a reinforcing element can be provided, which is firmly connected, in particular screwed, to the first tower column part and the second tower column part. Therefore, "away from" the base part means that the tower column parts are not connected to each other at their first end or end part, but at their second end or end part. This connection makes it possible to transfer forces from the first tower column part to the second tower column part and vice versa.

[0027] "Stiffness" is generally understood to mean the resistance of a body (in this case a bipod or a tower part) to elastic deformation imposed by an external load. This external load may include forces and / or moments. The stiffness is determined by the material used for the deformable body and its geometry. Thus, the geometry of the bipod, in particular the geometry of the mechanism, can be optimized to achieve the greatest possible stiffness. The higher the stiffness, the better the dynamic behavior.

[0028] According to one embodiment, the base part, the first tower part, the second tower part and the mechanism form an integral component, in particular a component manufactured from a single piece of material.

[0029] This means in particular that the base part, the first tower part, the second tower part and the mechanism do not consist of different substructures, but form a common component. The lever arms and the flexures described above can be manufactured by ablative manufacturing methods. For example, the lever arms can be manufactured by milling methods, wherein the flexures can be manufactured by etching methods. Thus, slots or cutouts are provided between the lever arms so that the lever arms can be moved around the flexures.

[0030] According to another embodiment, the first cutout is provided between the first tower section and the mechanism, and the second cutout is provided between the second tower section and the mechanism.

[0031] The cutouts may also be referred to as slots or gaps. The first cutout serves to separate or decouple the first tower section from the mechanism. Thus, the second tower section is separated or decoupled from the mechanism by means of the second cutout. Thus, the mechanism cannot exert a direct force on the tower section. Conversely, the tower section cannot therefore exert any force on the mechanism. Thus, preferably, the tower section is not directly connected to the mechanism, but is mechanically separated from it.

[0032] According to another embodiment, the mechanism has a first recess for accommodating the first actuating element and a second recess for accommodating the second actuating element, wherein the recesses are closed at the rear.

[0033] Preferably, exactly two actuating elements are provided. The actuating element can be a piezoelectric actuator. The actuating element can be referred to as an actuator. In particular, the actuating element is a linear actuating element or a linear actuator. The above-mentioned lever arm of the mechanism can be deflected by means of the actuating element in order to move the coupling element and change its attitude in this way. Both the first groove and the second groove have a rear wall. In particular, this means that the groove does not extend completely through the mechanism. By means of the rear side closure of the groove, a higher local rigidity of the mechanism can be achieved in the region of the groove.

[0034] According to another embodiment, the bipod further includes a reinforcement element connecting the first tower portion and the second tower portion facing away from the base portion.

[0035] The reinforcing element is particularly arranged at the rear side of the bipod. In particular, "rear" means that the reinforcing element is placed away from the actuating element. The reinforcing element is preferably in the form of a plate. Therefore, the reinforcing element can also be referred to as a reinforcing plate. Therefore, the terms "reinforcing element" and "reinforcing plate" can be interchanged as required. The reinforcing element can be, for example, a steel plate or an aluminum plate. The reinforcing element can be connected to the first tower part and the second tower part by means of fastening points. At these fastening points, the reinforcing element can be screwed to the tower parts.

[0036] According to another embodiment, the reinforcement element is connected to the base part.

[0037] For this purpose, the reinforcing element has additional connection points. For example, two connection points are provided for connecting the reinforcing element to the base part. At these connection points, the reinforcing element can be screwed to the base part.

[0038] According to a further embodiment, the reinforcement element has a recess facing away from the bipod.

[0039] In particular, the recess is positioned facing away from the mechanism and / or the tower portion. Preferably, the reinforcement element comprises a front side and a rear side, with the front side the reinforcement element is adjacent to the tower portion, while the recess is arranged at the rear side. By providing the recess, sufficient space can be created to mount additional components placed adjacent to the bipod.

[0040] According to another embodiment, the depression has a plurality of depression portions which extend to different depths into the reinforcement element, so that the depression has a stepped geometry.

[0041] For example, a first recessed portion, a second recessed portion and a third recessed portion are provided. The second recessed portion is deeper than the first recessed portion, and the third recessed portion is deeper than the second recessed portion. Thus, the recessed portion away from the tower column portion has a stepped or stepped geometry.

[0042] According to another embodiment, the bipod further includes an exoskeleton connecting the first tower portion and the second tower portion away from the base portion.

[0043] In this case, "away from" the base portion specifically means that the first tower section and the second tower section are connected to each other by means of an exoskeleton at the end or end portion of the respective tower section facing away from the base portion. The exoskeleton may also be referred to as a reinforcing frame or reinforcing portion. Therefore, the terms "exoskeleton", "reinforcing frame" and "reinforcing portion" may be interchanged as required. "Exoskeleton" may be understood in this context very generally to refer to a component or portion of a bipod that connects the first tower section to the second tower section away from the base section in order to reinforce the bipod.

[0044] According to a further embodiment, the first tower part, the second tower part and the outer frame are connected to one another in one piece, in particular in a single piece of material.

[0045] In particular, the mechanism is also connected in one piece, in particular in one piece, to the base part, which in turn is connected in one piece, in particular in one piece, to the first tower part and the second tower part. However, the exoskeleton itself is not connected to the mechanism. For this purpose, corresponding slots or cutouts are provided between the exoskeleton and the mechanism, which enable the mechanism or the lever arm and the flexure of the mechanism to move.

[0046] According to another embodiment, the mechanism is at least partially arranged within the exoskeleton.

[0047] In particular, this means that the exoframe at least partially encloses or surrounds the mechanism. For example, the exoframe comprises a rod-shaped base part, which is connected to the first tower part via a first connecting part and to the second tower part via a second connecting part. An opening can be provided in the base part, through which the movable coupling element is guided. Thus, the coupling element can be moved in the opening.

[0048] According to another embodiment, the base portion, the first tower portion, the second tower portion and the exoskeleton form a frame-type geometry that extends completely around the mechanism.

[0049] For example, the base part and the exoskeleton form two parts of the frame of the bipod extending in the y direction, while the tower part forms two parts of the frame extending in the z direction. Thus, the mechanism is arranged within this frame-type geometry, or within the frame formed by the base part, the tower part and the exoskeleton.

[0050] An optical system for a projection exposure apparatus is also proposed. The optical system comprises an optical element and at least one such bipod, wherein the at least one bipod is coupled to the optical element by means of a mechanism.

[0051] As mentioned above, the optical system can be an illumination optical unit or a projection optical unit of a projection exposure apparatus. The optical system can have a plurality of optical elements. The bipod is operatively connected to the optical element using the coupling element. The intermediate frame can be arranged between the bipod and the optical element. The optical element can have a plurality of reflector seats on the underside, wherein the coupling element of the bipod is operatively connected to one of these reflector seats.

[0052] According to one embodiment, the optical system further comprises a first bipod, a second bipod and a third bipod, wherein the optical element is adjustable in six degrees of freedom to change the optical element from an actual pose to a target pose and vice versa, and wherein each bipod is assigned two of the six degrees of freedom.

[0053] In particular, exactly three bipods are provided. Preferably one reflector mount for the optical element is assigned to each bipod. The bipod may be adapted to deflect the above-mentioned intermediate frame supporting the optical element. However, the intermediate frame is optional. With the bipod, the optical element can be moved from its actual posture to a target posture and vice versa. For example, the optical element in the target posture meets certain optical specifications or requirements that are not met by the optical element in the actual posture. In order to move the optical element from the actual posture to the target posture, the optical system comprises an adjustment device. The adjustment device may comprise three bipods. In addition, the adjustment device comprises an open-loop and closed-loop control unit, which is configured to control the bipod, in particular an actuating element of the bipod, to adjust or align the optical element.

[0054] Furthermore, a projection exposure apparatus having such a bipod and / or such an optical system is proposed.

[0055] The optical system is preferably a projection optical unit of a projection exposure apparatus. However, the optical system can also be an illumination optical unit of a projection exposure apparatus. The projection exposure apparatus can be an EUV lithography apparatus. EUV stands for "extreme ultraviolet" and means that the wavelength of the working light is between 0.1 nanometers and 30 nanometers. The projection exposure apparatus can also be a DUV lithography apparatus. DUV stands for "deep ultraviolet" and means that the wavelength of the working light is between 30 nanometers and 250 nanometers.

[0056] In the present case, "one" or "an" need not be understood as being limited to only one element. Instead, multiple elements may be provided, such as two, three or more. Any other number used herein should not be understood as limiting the exact number of elements. Instead, unless otherwise indicated, numerical deviations upward and downward are possible.

[0057] The embodiments and features described for the bipod apply correspondingly to the proposed optical system and / or the proposed projection exposure apparatus and vice versa.

[0058] Other possible implementations of the present invention also include the combination of features or embodiments described in the context of the exemplary embodiment that are not explicitly mentioned. In this case, those skilled in the art will also add various aspects as improvements or supplements to the corresponding basic forms of the present invention.

[0059] Further advantageous configurations and aspects of the invention are subject matter of the dependent claims and of the exemplary embodiments of the invention described below.In addition, the invention is explained in more detail based on preferred embodiments with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 shows a schematic meridional section of a projection exposure apparatus for DUV projection lithography;

[0061] Figure 2 Show according to Figure 1 A schematic diagram of an embodiment of an optical system of a projection exposure apparatus;

[0062] Figure 3 Show according to Figure 2 A schematic top view of an optical system;

[0063] Figure 4 Shown for use according to Figure 2 A schematic front view of an embodiment of a bipod of an optical system;

[0064] Figure 5 Show according to Figure 4 a schematic rear view of a bipod of; and

[0065] Figure 6 Shown for use according to Figure 2 A schematic front view of another embodiment of a bipod for an optical system.

[0066] Unless otherwise indicated, identical or functionally identical elements are provided with the same reference numerals in the figures. It should also be noted that the illustrations in the figures are not necessarily drawn to scale. DETAILED DESCRIPTION

[0067] Figure 1A schematic diagram of a projection exposure apparatus 1, in particular a DUV lithography apparatus, is shown, which comprises a beam shaping and illumination system 2 (also referred to herein as an "illumination optical unit") and a projection optical unit 4 (also referred to herein as a "projection lens"). In this case, DUV stands for "deep ultraviolet" and indicates that the wavelength of the working light is between 30 nm and 250 nm. The beam shaping and illumination system 2 and the projection optical unit 4 are preferably each arranged in a vacuum housing (not shown). Each vacuum housing is evacuated using a vacuum evacuation device (not shown). A machine room (not shown) surrounds the vacuum housing, in which a drive device for mechanically moving or setting optical elements can be arranged. In addition, an electrical controller and the like can also be arranged in the machine room.

[0068] The projection exposure apparatus 1 has a light source 6. For example, an ArF excimer laser which emits radiation 8 in the DUV range (e.g. 193 nm) can be provided as the light source 6. In the beam shaping and illumination system 2, the radiation 8 is focused and a desired working wavelength (working light) is filtered out of the radiation 8. The beam shaping and illumination system 2 can have optical elements, not shown, such as mirrors or lens elements.

[0069] After passing through the beam shaping and illumination system 2, the radiation 8 is directed onto a photomask or reticle 10. The photomask 10 is formed as a transmissive optical element and can be arranged outside the beam shaping and illumination device 2 and the projection optical unit 4. The photomask 10 has a structure which is imaged in reduced form on a wafer 12 by the projection optical unit 4.

[0070] The projection optical unit 4 has a plurality of lens elements 14, 16, 18 and / or reflectors 20, 22 for imaging the photomask 10 onto the wafer 12. In this case, the individual lens elements 14, 16, 18 and / or reflectors 20, 22 of the projection optical unit 4 can be arranged symmetrically with respect to the optical axis 24 of the projection optical unit 4. It should be noted that the number of lens elements 14, 16, 18 and reflectors 20, 22 shown here is purely exemplary and is not limited to the number shown. A greater or lesser number of lens elements 14, 16, 18 and / or reflectors 20, 22 can also be provided.

[0071] The air gap between the last lens element (not shown) and the wafer 12 can be replaced by a liquid medium 26 having a refractive index greater than 1. The liquid medium 26 can be, for example, high purity water. This setup is also known as immersion lithography, which increases the lithographic resolution. The medium 26 can also be referred to as an immersion liquid.

[0072] Figure 2 A schematic diagram of an embodiment of an optical system 100 for a projection exposure apparatus 1 is shown. Figure 3 A schematic top view of the optical system 100 is shown. Figure 2 and Figure 3 .

[0073] The optical system 100 may be the above-mentioned projection optical unit 4 or a part of such a projection optical unit 4. Therefore, the optical system 100 may also be referred to as a projection optical unit. However, the optical system 100 may also be a beam shaping and illumination system 2 as explained previously, or a part of a beam shaping and illumination system 2. Therefore, the optical system 100 may also be referred to as a beam shaping and illumination system. However, it is assumed hereinafter that the optical system 100 is a projection optical unit 4 or a part of a projection optical unit 4. The optical system 100 is suitable for DUV lithography. However, the optical system 100 may also be suitable for EUV lithography.

[0074] The optical system 100 may include a plurality of optical elements 102. Figure 2 and 3 Only one of them is shown in the figure. Therefore, only one optical element 102 is discussed below. The optical element 102 can be one of the lens elements 14, 16, 18 or one of the reflectors 20, 22. The following text assumes that the optical element 102 is one of the reflectors 20, 22. The optical element 102 includes a substrate 104 and an optically effective surface 106, such as a reflector surface. The substrate 104 can also be called a reflector substrate. The substrate 104 can include glass, ceramics, glass ceramics or other suitable materials.

[0075] The optically active surface 106 is arranged on the front side 108 of the substrate 104. The optically active surface 106 can be realized by means of a coating applied to the front side 108. The optically active surface 106 is a reflective mirror surface. The optically active surface 106 is suitable for reflecting illumination radiation, in particular DUV radiation, during operation of the optical system 100. Figure 3 In the top view of FIG. 1 , the geometric shape of the optically effective surface 106 may be an oval or an ellipse. The geometric shape of the optical element 102 or the substrate 104 may be a triangle. However, in general, any geometric shape is acceptable.

[0076] The rear side 110 of the optical element 102 faces away from the optically active surface 106 or the front side 108. The rear side 110 has no defined optical properties. Specifically, the rear side 110 is not a reflective mirror surface and therefore has no reflective properties.

[0077] A plurality of reflector seats 112, 114, 116 are arranged on the rear side 110. A first reflector seat 112, a second reflector seat 114 and a third reflector seat 116 are provided. In other words, the optical element 102 comprises exactly three reflector seats 112, 114, 116. The geometry of the reflector seats 112, 114, 116 can have the same design. The reflector seats 112, 114, 116 are cylindrical and have a convex shape along the lower side. Figure 2The orientation extends beyond the rear side 110. The reflector mounts 112, 114, 116 form the corners of an imaginary triangle.

[0078] The optical element 102 or the optically active surface 106 has six degrees of freedom, namely, three degrees of freedom of translation respectively 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, and three degrees of freedom of rotation respectively around the x-direction x, the y-direction y and the z-direction z. In other words, the position and orientation of the optical element 102 or the optically active surface 106 can be determined or described using the six degrees of freedom.

[0079] In particular, the “position” of the optical element 102 or the optically active surface 106 is understood to mean its coordinates or the coordinates of a measuring point arranged on the optical element 102 relative to the x-direction x, the y-direction y and the z-direction z. The “orientation” of the optical element 102 or the optically active surface 106 is understood to mean in particular its tilt relative to the three spatial directions x, y, z. That is, the optical element 102 or the optically active surface 106 can be tilted about the x-direction x, the y-direction y and / or the z-direction z.

[0080] This results in six degrees of freedom for the position and / or orientation of the optical element 102 or the optically effective surface 106. The "pose" of the optical element 102 or the optically effective surface 106 encompasses both its position and its orientation. Therefore, the term "pose" can be replaced by the term "position and orientation", and vice versa.

[0081] Figure 2 The actual posture IL of the optical element 102 or the optically effective surface 106 is shown in solid lines, and the target posture SL of the optical element 102 or the optically effective surface 106 is shown in dotted lines, and the reference numerals thereof are 102' and 106'. The optical element 102 can move from its actual posture IL to the target posture SL, and vice versa. For example, the optical element 102 in the target posture SL satisfies a specific optical specification or requirement that the optical element 102 in the actual posture IL does not satisfy.

[0082] In order to move the optical element 102 from the actual posture IL to the target posture SL, the optical system 100 includes an adjustment device 200. The adjustment device 200 is configured to adjust the optical element 102. Specifically, "adjustment" or "alignment" is understood herein to mean a change in the posture of the optical element 102. For example, the optical element 102 can be moved from the actual posture IL to the target posture SL using the adjustment device 200, and vice versa. Therefore, the adjustment device 200 can be used to adjust or align the optical element 102 in all the above six degrees of freedom.

[0083] The adjustment device 200 includes a plurality of manipulators or bipods 202, 204, 206, which are arranged in a Figure 21 and 2. The optical element 102 is shown only highly schematically in FIG. 1. Each reflector mount 112, 114, 116 is assigned one bipod 202, 204, 206. In particular, this means that exactly three bipods 202, 204, 206 are provided. Two of the above-mentioned degrees of freedom can be assigned to each bipod 202, 204, 206. Thus, using three bipods 202, 204, 206, the optical element 102 can be adjusted in all six degrees of freedom.

[0084] The first bipod 202 is assigned to the first reflector mount 112. The second bipod 204 is assigned to the second reflector mount 114. The third bipod 206 is assigned to the third reflector mount 116. The bipods 202, 204, 206 are all designed the same. Therefore, only the first bipod 202 and the first reflector mount 112 are discussed below, which are referred to as the bipod 202 and the reflector mount 112, respectively.

[0085] The bipod 202 is coupled to a fixture 212 using a first connection point 208 and a second connection point 210. The fixture 212 may be a force frame or any other immovable structure. For example, the bipod 202 is connected to the fixture 212 using screw connections at the connection points 208, 210. The bipod 202 further includes a coupling element 214, which is coupled to a reflector mount 112 assigned to the bipod 202. An intermediate frame (not shown) may be provided between the coupling element 214 and the reflector mount 112.

[0086] Two actuators or actuating elements (not shown) are assigned to the bipod 202, which can be controlled by means of an open-loop and closed-loop control unit 216 of the adjustment device 200. All actuating elements of all bipods 202, 204, 206 are actively connected to the open-loop and closed-loop control unit 216, so that the open-loop and closed-loop control unit 216 can adjust the optical element 102 in all six degrees of freedom by means of appropriate control of these actuating elements.

[0087] Figure 4 A schematic front view of an embodiment of a bipod 202A as described above is shown. Figure 5 A schematic rear view of the bipod 202A is shown. Figure 4 and Figure 5 .

[0088] In order to increase the dynamics of the optical system 100 and the bipod 202A, it is necessary to improve the rigidity of the bipod 202A. The term "rigidity" is generally understood herein to refer to the resistance of a component to elastic deformation due to external loads, in particular forces and / or moments. Rigidity provides a correlation between the load on a component and its deformation. The rigidity is determined by the material of the component and its geometry, in particular its shape and size.

[0089] The reinforcement is achieved constructively by adjusting the design of the bipod 202A and also by attaching a reinforcement structure or frame structure to be explained below, which gives the bipod 202A additional rigidity. In addition, the dynamics or mechanism of the bipod 202A to be explained below is optimized to be able to achieve high rigidity and high dynamics at the same time.

[0090] Local deformation of the bipod 202A can lead to degradation of the dynamic performance of the optical system 100 or the bipod 202A. The aim here is to achieve a structure that is as strong as possible within a limited installation space. As the requirements related to dynamic behavior increase, so does their complexity. Therefore, as the installation space becomes narrower, the requirements for the travel and position accuracy of the bipod 202A become higher. Due to these requirements, the bipod 202A must be designed to be strong in order to increase its overall rigidity.

[0091] The geometric shape of the bipod 202A is basically in the form of a panel. In this context, "in the form of a panel" means that the geometric extent of the bipod 202A observed along the y direction y and the z direction z is significantly greater than the geometric extent of the bipod 202A observed along the x direction x. The cross section of the bipod 202A is generally rectangular. However, the coupling element 214 can be cylindrical.

[0092] The bipod 202A includes a pole-shaped base portion 218 that extends along Figure 4 and Figure 5 The first tower part 220 and the second tower part 222 are respectively arranged on the end sides of the base part 218. The tower parts 220, 222 extend along the z-direction z and are therefore arranged perpendicular to the base part 218. The base part 218 and the tower parts 220, 222 are formed as one piece, in particular as a single piece of material.

[0093] "Integral" or "single piece" in this context specifically means that the base portion 218 and the tower portions 220, 222 are not composed of multiple sub-components, but form a common component. Specifically, "single piece of material" means that the base portion 218 and the tower portions 220, 222 are all made of the same material. Suitable materials used are, for example, metal materials, in particular aluminum alloys or steel alloys.

[0094] At the first tower part 220, a first connection point 208 is provided, which can be, for example, a screw hole. Therefore, the first tower part 220 is connected to the fixing device 212 using the first connection point 208. Therefore, the second connection point 210 can also be a screw hole, which is provided at the second tower part 222. Therefore, the second tower part 222 is connected to the fixing device 212 using the second connection point 210.

[0095] When viewed along the y-direction y, the connection points 208, 210 are spaced apart from each other. When viewed along the z-direction z, the connection points 208, 210 are arranged above the base portion 218. Therefore, the base portion 218 itself does not have a connection point 208, 210. Therefore, the base portion 218 does not contain a connection point 208, 210. In other words, the base portion 218 is free of connection points or lacks connection points. Therefore, the base portion 218 itself is not directly connected to the fixture 212.

[0096] Between the first tower section 220 and the second tower section 222, a kinematic or mechanism 224 is arranged, the structural design of which will not be explained in further detail. By means of the mechanism 224, the coupling element 214 can be linearly moved along the z-direction z and / or tilted about the x-direction x. It is possible to perform a linear movement only along the z-direction z, a linear movement along the y-direction y, a linear movement along a diagonal direction in a plane defined by the y-direction y and the z-direction z, or a combination of a linear movement and a rotational movement about the x-direction x. Figure 4 A purely linear movement of the coupling element 214 along the z-direction z is shown. The coupling element 214 is part of a mechanism 224 .

[0097] The coupling element 214 can thus be moved with two degrees of freedom and moved from a starting position AL shown with a solid line to any end position EL shown with a dashed line, wherein the coupling element is referenced by 214'. The number of end positions EL is arbitrary. In particular, any intermediate position (not shown) can be set between the starting position AL and the end position EL.

[0098] The mechanism 224 has a first actuating element 226 and a second actuating element 228 different from the first actuating element 226. The actuating elements 226 and 228 may also be referred to as actuators. The actuating elements 226 and 228 are piezoelectric actuating elements or piezoelectric actuators or may be referred to similarly. The mechanism 224 has a first pocket 230 in which the first actuating element 226 is accommodated and a second pocket 232 in which the second actuating element 228 is accommodated. Figure 4 In the orientation, the grooves 230, 232 are closed at the rear end.

[0099] As previously described, the actuating elements 226, 228 can be controlled using open-loop and closed-loop control units 216 to change the attitude of the coupling element 214, or to change the attitude of the optical element 102 together with all three bipods 202, 202A, 204, 206. In order to transmit the movement or travel 234, 236 of the corresponding actuating elements 226, 228 to the coupling element 214, the mechanism 224 includes a plurality of lever arms (not shown) formed by cutouts and flexures, about which the lever arms can pivot.

[0100] For example, the mechanism 224 can be used in a transmission manner to increase the corresponding stroke 234, 236. Therefore, the mechanism 224 increases the corresponding stroke 234, 236 toward the coupling element 214, so that a small deflection of the corresponding actuating element 226, 228 results in a larger deflection of the coupling element 214. The mechanism 224 can have a certain transmission ratio, using which the corresponding stroke 234, 236 is converted into a corresponding deflection of the coupling element 214.

[0101] Apart from the actuating elements 226, 228, the mechanism 224 is an integral component, in particular a component manufactured from a single piece of material. The lever arm described above can be manufactured by a milling method, wherein the flexure can be manufactured by means of an etching method. The mechanism 224, the coupling element 214 and the base part 218 form an integral component, in particular a component manufactured from a single piece of material. In particular, this means that the mechanism 224 can be part of the base part 218 or vice versa.

[0102] In each case a slot or cutout 238, 240 is provided between the tower section 220, 222 and the mechanism 224 so that the mechanism 224 is not directly connected to the tower section 220, 222. A first cutout 238 and a second cutout 240 are provided. The first cutout 238 is provided between the first tower section 220 and the mechanism 224. The second cutout 240 is provided between the second tower section 222 and the mechanism 224.

[0103] Since the tower parts 220, 222 are not connected to the mechanism 224, they may deform in an undesirable manner. In order to increase the rigidity of the bipod 202A, a reinforcing element 242 is provided, which connects the tower parts 220, 222 to each other and thus strengthens the bipod 202A. The reinforcing element 242 is in the form of a plate and can therefore also be referred to as a reinforcing plate. Therefore, the terms "reinforcing element" and "reinforcing plate" can be interchanged as required. The reinforcing element 242 is part of the bipod 202A.

[0104] The reinforcing element 242 can be made of a metal material, for example a steel alloy or an aluminum alloy. Compared to the bipod 202A, the wall thickness of the reinforcing element 242 is significantly reduced when viewed along the x-direction x. The reinforcing element 242 can be sheet-shaped or a sheet material, in particular a steel sheet or an aluminum sheet.

[0105] The reinforcement element 242 comprises a plurality of fastening points 244, 246, 248, 250. The fastening points 244, 246, 248, 250 may be openings or holes provided in the fastening element 242. A first fastening point 244 assigned to the first tower section 220, a second fastening point 246 assigned to the second tower section 222, a third fastening point 248 assigned to the base section 218, and a fourth fastening point 250 also assigned to the base section 218 are provided. The reinforcement element 242 may be screwed to the tower sections 220, 222 at the fastening points 244, 246 and to the base section 218 at the fastening points 248, 250.

[0106] A depression or recess 252 is provided in the reinforcing element 242 facing away from the bipod 202A, the depression 252 extending into the reinforcing element 242, viewed along the x-direction x, in order to locally weaken or reduce the wall thickness of the reinforcing element 242. The depression 252 may be stepped and have a plurality of recessed portions 254, 256, 258. A first recessed portion 254, a second recessed portion 256 and a third recessed portion 258 are provided.

[0107] When viewed along the x-direction x, the second recessed portion 256 extends deeper into the reinforcing element 242 than the first recessed portion 254 extends into the reinforcing element 242, and when viewed along the x-direction x, the third recessed portion 258 extends deeper into the reinforcing element 242 than the second recessed portion 256 extends into the reinforcing element 242. As a result, the recessed portion 252 has a stepped or staircase-like geometry.

[0108] Therefore, the bipod 202A is structurally adapted to Figure 4 and Figure 5 In each case, tower sections 220 , 222 are arranged on the left and right sides of the base section 218 .

[0109] One respective connection point 208, 210 of the bipod 202A is disposed upwardly to an end of the respective tower portion 220, 222 facing away from the base portion 218. Since the tower portions 220, 222 are connected to the base portion 218 at only one end and the respective connection profiles between the respective tower portions 220, 222 and the base portion 218 are relatively thin, dynamic excitation of the bipod 202A may cause the tower portions 220, 222 to generate undesirable vibrations.

[0110] To dampen these vibrations of tower sections 220, 222, and any associated deformations at the transitions between tower sections 220, 222 and base section 218, tower sections 220, 222 and base section 218 are connected to one another using reinforcing elements 242. Reinforcing elements 242 provide additional rigidity to tower sections 220, 222.

[0111] Due to the narrow installation space, the reinforcing element 242 is recessed on the outside, that is, with a recess 252 facing away from the tower parts 220, 222, so as to have a sufficient distance from the adjacent components. The rear recess 252 of the reinforcing element 242 can be used as a movement space for the dynamics of the bipod. In addition, the grooves 230, 232 are closed on one side. This local material reinforcement ensures that the local rigidity in the area of ​​the grooves 230, 232 is increased.

[0112] The mechanism 224 is optimized in the design of the bipod 202A. The flexures of the mechanism 224 are optimized in terms of stress and stiffness. In addition, the alignment of the swivel joints where the swivel area is located is adjusted to achieve higher stiffness while maintaining joint stress. The design of the bipod 202A allows for adjustments to the manufacturing process. The contours of the bipod 202A are achieved by milling and the flexures are etched.

[0113] Figure 6 A schematic front view of another embodiment of the bipod 202B described above is shown.

[0114] The design of the bipod 202B is substantially the same as that of the bipod 202A. Therefore, only the differences between the two embodiments of the bipods 202A and 202B will be discussed below.

[0115] Compared to the bipod 202A, the bipod 202B does not have the reinforcing element 242 as previously explained, but has a so-called exoskeleton 260. The exoskeleton 260 may also be referred to as a reinforcing frame or reinforcing portion. Therefore, the terms "exoskeleton", "reinforcing frame" and "reinforcing portion" may be interchanged as desired.

[0116] At the ends of the tower parts 220, 222 facing away from the base part 218, an exoskeleton 260 connects the tower parts 220, 222. In this case, the tower parts 220, 222 and the exoskeleton 260 form an integral component, in particular a component manufactured from a single piece of material, in particular the base part 218, the first tower part 220, the second tower part 222, the mechanism 224 and the exoskeleton 260 form an integral component, in particular a component manufactured from a single piece of material.

[0117] The base portion 218, the two tower portions 220, 222 and the exoskeleton 260 form a frame-like geometry that extends completely around the mechanism 224 and thus encloses or surrounds the mechanism. At least part of the mechanism 224 is arranged within the exoskeleton 260 or the exoskeleton 260 at least partially encloses the mechanism 224.

[0118] The exoskeleton 260 has a base portion 262 with an opening 264 through which the coupling element 214 is guided. The coupling element 214 has sufficient clearance in the opening 264 for the coupling element 214 so that the coupling element 214 can be moved by the mechanism 224 to adjust its posture as described above.

[0119] The base portion 262 is connected to the first tower portion 220 in an integral manner, in particular in a single piece of material, by means of a first connecting portion 266. Furthermore, the base portion 262 is connected to the second tower portion 222 in an integral manner, in particular in a single piece of material, by means of a second connecting portion 268. This gives the exoskeleton 260 a stepped geometry.

[0120] A slot or cutout 270 is provided between the first connecting portion 266 and the mechanism 224. A corresponding slot or cutout 272 is provided between the second connecting portion 268 and the mechanism 224. A corresponding slot or cutout 274 is also provided between the base portion 262 and the mechanism 224.

[0121] The design of the bipod 202B includes an exoskeleton 260 and a base portion 218, which may include a mechanism 224. The exoskeleton 260 and the base portion 218 are integrally connected to each other via the tower portions 220, 222, so that the bipod 202B obtains stable connection points 208, 210.

[0122] In addition, the exoskeleton 260 provides additional rigidity. Since the exoskeleton 260 results in a larger overall width, lateral auxiliary holes can be provided for manufacturing radial decoupling joints. In addition, the geometry of the decoupling joint can be reproduced on the exoskeleton 260. The manufacturing process for the grooves 230, 232 based on a single-sided opening is adjusted to meet the required precision of the functional surface.

[0123] Although the present invention has been described with reference to exemplary embodiments, the present invention can be modified in various ways.

[0124] Reference numerals list

[0125] 1 Projection exposure equipment

[0126] 2 Beam shaping and illumination system

[0127] 4 Illumination optical unit

[0128] 6 Light Source

[0129] 8 Radiation

[0130] 10 Photomask

[0131] 12 chips

[0132] 14 Lens elements

[0133] 16 Lens elements

[0134] 18 Lens elements

[0135] 20 Reflector

[0136] 22 Reflector

[0137] 24 Optical Axis

[0138] 26 Medium

[0139] 100 Optical System

[0140] 102 Optical Components

[0141] 102' Optical Components

[0142] 104 substrate

[0143] 106 Optically effective surface

[0144] 106' optical effective surface

[0145] 108 front side

[0146] 110 rear side

[0147] 112 Reflector seat

[0148] 114 Reflector seat

[0149] 116 Reflector seat

[0150] 200 Adjustment device

[0151] 202 Bipod

[0152] 202A Bipod

[0153] 202B Bipod

[0154] 204 Bipod

[0155] 206 Bipod

[0156] 208 Connection Points

[0157] 210 Connection Points

[0158] 212 Fixtures

[0159] 214 Coupling element

[0160] 214' coupling element

[0161] 216 Open-loop and closed-loop control units

[0162] 218 Base part

[0163] 220 Tower column

[0164] 222 Tower column

[0165] 224 Institutions

[0166] 226 Actuating element

[0167] 228 Actuating element

[0168] 230 Grooves

[0169] 232 groove

[0170] 234 Itinerary

[0171] 236 Itinerary

[0172] 238 Incision

[0173] 240 Incision

[0174] 242 Reinforcement elements

[0175] 244 fastening points

[0176] 246 fastening points

[0177] 248 fastening points

[0178] 250 fastening points

[0179] 252 Depression

[0180] 254 Depression

[0181] 256 Concave part

[0182] 258 Depression

[0183] 260 Exoskeleton

[0184] 262 Base part

[0185] 264 Opening

[0186] 266 Connection part

[0187] 268 Connection part

[0188] 270 Incision

[0189] 272 Incision

[0190] 274 Incision

[0191] AL Starting position

[0192] EL Ending Stance

[0193] IL Actual posture

[0194] M1 Reflector

[0195] M2 Reflector

[0196] M3 Reflector

[0197] M4 Reflector

[0198] M5 Reflector

[0199] M6 Reflector

[0200] SL Target Attitude

[0201] xx Direction

[0202] yy direction

[0203] zz direction

Claims

1. A bipod (202, 202A, 202B, 204, 206) for adjusting an optical element (102, 102') of an optical system (100) of a projection exposure apparatus (1), comprising: a mechanism (224) capable of being coupled to the optical element (102, 102') to adjust the optical element (102, 102'); a base portion (218); A first tower portion (220) extending from the base portion (218); a second tower portion (222), different from the first tower portion (220) and also extending from the base portion (218); wherein the mechanism (224) is disposed between the first tower column portion (220) and the second tower column portion (222); and The first tower column part (220) and the second tower column part (222) are connected to each other away from the base part (218) to increase the rigidity of the bipod (202, 202A, 202B, 204, 206).

2. A bipod as claimed in claim 1, wherein the base part (218), the first tower part (220), the second tower part (222) and the mechanism (224) form an integral component, in particular a component consisting of a single piece of material.

3. The bipod of claim 1, wherein a first cutout (238) is disposed between the first tower portion (220) and the mechanism (224), and wherein a second cutout (240) is disposed between the second tower portion (222) and the mechanism (224).

4. A bipod as claimed in any one of claims 1 to 3, wherein the mechanism (224) has a first recess (230) for accommodating a first actuating element (226) and a second recess (232) for accommodating a second actuating element (228), and wherein the recesses (230, 232) are closed at the back.

5. The bipod of any one of claims 1 to 4, further comprising a reinforcing element (242) connecting the first tower portion (220) and the second tower portion (222) away from the base portion (218).

6. The bipod of claim 5, wherein the reinforcement element (242) is connected to the base portion (218).

7. The bipod of claim 5 or 6, wherein the reinforcing element (242) has a recess (252) facing away from the bipod (202, 202A, 204, 206).

8. The bipod of claim 7, wherein the recess (252) has a plurality of recessed portions (254, 256, 258) extending to different depths of the reinforcing element (242) such that the recess (252) has a stepped geometry.

9. The bipod of any one of claims 1 to 4, further comprising an exoskeleton (260) connecting the first tower portion (220) and the second tower portion (222) away from the base portion (218).

10. The bipod of claim 9, wherein the first tower portion (220), the second tower portion (222) and the outer frame (260) are connected in one piece, in particular, are connected as one piece of material.

11. A bipod as claimed in claim 9 or 10, wherein the mechanism (224) is at least partially arranged within the outer frame (260).

12. A bipod as claimed in any one of claims 9 to 11, wherein the base portion (218), the first tower portion (220), the second tower portion (222) and the exoskeleton (260) form a frame-type geometric structure and extend completely around the mechanism (224).

13. An optical system (100) for a projection exposure apparatus (1), comprising: an optical element (102, 102'); and At least one bipod (202, 202A, 202B, 204, 206) according to any one of claims 1 to 12; At least one of the bipods (202, 202A, 202B, 204, 206) is coupled to the optical element (102, 102') by means of the mechanism (224).

14. The optical system of claim 13, further comprising a first bipod (202, 202A, 202B), a second bipod (204), and a third bipod (206), wherein the optical element (102, 102') is adjustable in six degrees of freedom in order to move the optical element (102, 102') from an actual pose (IL) to a target pose (SL) and vice versa; and Each bipod (202, 202A, 202B, 204, 206) is allocated two degrees of freedom among the six degrees of freedom.

15. A projection exposure apparatus (1) comprising a bipod (202, 202A, 202B, 204, 206) according to any one of claims 1 to 12 and / or an optical system (100) according to claim 13 or 14.

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