Device, holding device, arrangement, system and method for holding an optical element; lithography system

Abstract

The invention relates to a device (1) for holding an optical element (2), in particular an optical element of a mask inspection system or a lithography system, comprising a mounting point (3) for connection with the optical element (2), a support (4), and a support base (5). The mounting point (3) is connected to the support (4). The support (4) has at least one leg (6) and an ankle joint (7), wherein the ankle joint (7) pivotally connects a lower end (6a) of the leg (6), facing away from the mounting point (3), to the support base (5). According to the invention, the ankle joint (7) has a support joint (7a) and a transverse joint (7b), wherein the support joint (7a) pivotally connects the lower end (6a) of the leg (6) directly to the support base (5).

Description

[0001] The invention relates to a device for holding an optical element, in particular an optical element of a mask inspection system or a lithography system.

[0002] The invention also relates to a holding device for holding an optical element, in particular an optical element of a mask inspection system or a lithography system.

[0003] The invention also relates to an arrangement for holding an optical element, in particular an optical element of a mask inspection system or a lithography system.

[0004] The invention further relates to a system comprising an optical element, in particular an optical element of a mask inspection system or a lithography system.

[0005] The invention also relates to a method for holding and, in particular, for positioning and / or aligning an optical element, especially an optical element of a mask inspection system or a lithography system.

[0006] The invention further relates to a mask inspection system for inspecting a photomask, in particular a reticle for a projection exposure system, comprising a lighting device with a radiation source and optics comprising at least one optical element, and a detection device.

[0007] The invention further relates to a lithography system, in particular a projection exposure system for semiconductor lithography, with an illumination system comprising a radiation source and optics comprising at least one optical element.

[0008] Optical elements require a suitable mounting to fix, hold, or store them within an optical system and, if necessary, to allow for controlled movement and / or tilting. Even during installation, uneven mounting or contact surfaces, manufacturing tolerances, angular or positional errors, or differences in thermal expansion between the optical element and its environment can affect the mounting or the optical element itself. During operation, differences in thermal expansion between the optical element and its environment can also be caused by light absorption. Actuators are used to exert additional forces for any necessary or desired positioning and / or alignment.During installation, operation, and positioning and / or alignment, unwanted forces and moments are transferred to the optical element, leading to deformations of the optical element and / or an optical surface of the optical element. These deformations can impair the functionality of the optical element, especially when high precision in the beam path and / or beam profile is required, such as for the best possible image quality and minimal aberrations in semiconductor lithography. Both lithography systems themselves and mask inspection systems, which allow for the prior inspection and examination of photomasks or reticles for the lithography systems, can benefit from reduced deformations of the optical elements.

[0009] For many applications, particularly in high-performance optics, optical elements must be able to move at least translationally in the lateral and axial directions and rotationally around the radial, tangential, and axial axes. This can lead to deformations of the optical elements or optical surfaces. Such deformations typically originate from parasitic forces and / or moments or parasitic loads, which occur as an undesirable or passive side effect of the intended active positioning and / or alignment of the optical element. This is primarily due to the fact that positioning mechanisms for moving the optical elements are constructed from spring joints, which, during their joint movement and thus during movement of the positioning mechanism, generate deforming forces, torques, and / or bending moments. These parasitic loads are at least partially absorbed by the optical element.intercepted and can therefore unintentionally change the shape of the optical element.

[0010] Besides positioning and / or aligning the optical element, the mount also has a fundamental holding function. In this respect, vibrations play a crucial role; these are generally undesirable and, like deformations of the optical element, should be minimized to achieve the best possible image quality and prevent optical artifacts.

[0011] Various kinematic systems for mounting, positioning, and / or aligning optical elements are known in the prior art. So-called bipods with two bipod legs are frequently used for this purpose.

[0012] According to the general state of the art, the adjustment of such bipods can be achieved, for example, by actuating them in the longitudinal or axial direction of the bipod legs. A longitudinal displacement of the bipod legs by means of an actuator results in a tangential and / or axial displacement of the optical element. It is common practice for the bipod legs to have simple joints at their ends, in particular tilting joints or leaf spring joints, so that the bipod legs are compliant with translations, especially perpendicular to the bipod leg, and with tilting.

[0013] A disadvantage has emerged in that parasitic loads, originating from the elastic properties or stiffness of the joints, are transferred unhindered into the optical element, causing deformations. In particular, the restoring forces of the joints of a bipod leg are responsible for this. These forces can be bent or deflected longitudinally, for example, by the displacement of an adjacent bipod leg. The resulting parasitic bending moments cannot be absorbed, or at least not completely absorbed, by the displaced, adjacent bipod leg and must instead be supported by the optical element, leading to unwanted deformations.

[0014] Alternatives to longitudinal actuation of the bipod legs are also known. German patent DE 10 2018 200 178 A1 discloses a projection exposure system in which a bipod-shaped kinematic mechanism is used to adjust the optical element, and in which at least a component of movement is provided in the transverse direction. In addition, the actuation can be performed along a line connecting the bases of the two bipod legs, or, by using an actuating lever, displacements of the bipod leg can also be made in the transverse direction by means of an offset between the ankle joint and the joint of the actuating lever. In both cases, parasitic bending moments can be at least partially compensated, thereby preventing unwanted deformations of the optical element. In this way, the optical element does not have to withstand any or hardly any radial bending moments.

[0015] However, a disadvantage of the solution according to DE 10 2018 200 178 A1 lies in the indirect force transmission, i.e., the convoluted force flow, which makes the arrangement comparatively susceptible to vibration excitation. Furthermore, this results in a relatively high force requirement for adjustment.

[0016] The present invention is based on the objective of creating a device for holding an optical element which is improved compared to the prior art and in particular reduces unwanted deformations of the optical element.

[0017] According to the invention, this problem is solved by a device having the features mentioned in claim 1.

[0018] The present invention also aims to create a holding device for mounting an optical element that is improved compared to the prior art and in particular reduces unwanted deformations of the optical element.

[0019] According to the invention, this problem is solved by a holding device with the features mentioned in claim 17.

[0020] The present invention also aims to create an arrangement for holding an optical element that is improved compared to the prior art and in particular reduces unwanted deformations of the optical element.

[0021] According to the invention, this problem is solved by an arrangement with the features mentioned in claim 23.

[0022] The present invention further aims to create a system with an optical element that is improved compared to the prior art and in particular enables improved mounting of the optical element or reduces unwanted deformations of the optical element.

[0023] According to the invention, this problem is solved by a system with the features mentioned in claim 25.

[0024] The present invention also aims to provide a method for holding and, in particular, for positioning and / or aligning an optical element, which is improved compared to the prior art and, in particular, reduces unwanted deformations of the optical element.

[0025] According to the invention, this problem is solved by a method with the features mentioned in claim 27.

[0026] Furthermore, the present invention is based on the objective of creating a mask inspection system which has optical elements which are designed to avoid the disadvantages of the prior art, in particular by reducing unwanted deformations of the optical element.

[0027] According to the invention, this problem is solved by a mask inspection system with the features mentioned in claim 28.

[0028] The present invention further aims to create a lithography system which has optical elements that are designed to avoid the disadvantages of the prior art, in particular by reducing unwanted deformations of the optical element.

[0029] According to the invention, this problem is solved by a lithography system with the features mentioned in claim 29.

[0030] The device according to the invention for holding or supporting an optical element, in particular an optical element of a mask inspection system or a lithography system, has a mounting point for connection with the optical element. The device according to the invention further comprises a support and a support base, wherein the mounting point is connected to the support. The support has at least one leg and a joint assembly, wherein the joint assembly pivotally connects a lower end of the leg, facing away from the mounting point, to the support base. According to the invention, the joint assembly has a support joint and a transverse joint, wherein the support joint pivotally connects the lower end of the leg directly to the support base.

[0031] The device or kinematics according to the invention is advantageously suitable for holding or storing optical elements under minimal parasitic loads.

[0032] By combining two joints—that is, by combining the support joint and the transverse joint into a single ankle joint—instead of using a single ankle joint, transverse displacements of the support are enabled not only in the longitudinal direction but also in the transverse direction, in order to at least approximately or as completely as possible compensate for parasitic bending moments. Simultaneously, the direct connection of the rod leg to the support foot via the support joint allows for a stiffer connection of the optical element to the mount, frame, or housing compared to the prior art. Furthermore, the comparatively direct force transmission from the mounting point on the optical element to the support foot has proven advantageous in preventing vibration excitation and resonance. Due to these various aspects, the inventive solution for mounting optical elements results in no or minimal deformation of the optical element.In the context of mask inspection or lithography systems, this leads to a significantly improved image quality, since an optical element held or mounted with such reduced deformation experiences hardly any or no image errors caused by external influences.

[0033] The device can also be configured, in particular, to align and / or position the optical element or to move it in a guided manner. For this purpose, the rod legs can, for example, be movable. Thus, the present invention can solve the problem of creating a device for positioning and / or aligning an optical element that minimizes unwanted deformations of the optical element.

[0034] The advantages of the device according to the invention arise primarily from the fact that, by dividing the ankle joint or ankle joint assembly of the support into a support joint and a transverse joint, which are preferably independently movable and oriented differently in space, the device can compensate for parasitic forces and / or moments that would otherwise be absorbed by the optical element and deform it, by means of counter-bending of the support joint or transverse joint and / or counter-tilting of components of the device, for example, an actuating lever described in more detail below. Counter-tilting can be achieved in particular by deflecting the support joint and / or the transverse joint. It is particularly advantageous for the function of the invention if the support joint can accommodate translational movements or...Allows transverse movements of the lower end of the rod leg relative to the preferably as fixed as possible support foot, wherein the translational movement can be transferred to the lower end of the rod leg by means of the transverse joint by an actuator preferably used for this purpose.

[0035] Typically, several devices according to the invention are used together to hold the optical element. In particular, two devices according to the invention can together form a bipod or a holding device. The two devices can form the legs of the bipod. Unlike the prior art, these do not have a single ankle joint with a uniform axis, but rather an ankle joint consisting of at least one support joint and a transverse joint with two different axes or orientations. Preferably, three such bipods or holding devices, or even six individual devices, are used for positioning and / or aligning an optical element as a type of hexapod or hexapod arrangement. In particular, several holding points can be provided at which the optical element is fixed and which together support the optical element.

[0036] If the devices of a bipod or a holding device for positioning and / or aligning the optical element are actively moved from their rest position or deliberately adjusted, the devices of another bipod fixed to the optical element, in particular their ankle joints, can also be passively deflected. The present invention is also suitable for this purpose.

[0037] The optical element can be, for example, a mirror or a lens. However, it can also be any other optical element. The optical element can define and / or have an optical surface. In particular, the optical surface of the optical element can be the surface or reflective surface of a mirror or the median plane of a lens.

[0038] The mounting point at least partially supports the optical element. The optical element is fixed to the mounting point. The mounting point can, in particular, be designed as a bracket. The optical element and the device or the support can be connected by the mounting point. The connection can, in particular, also be formed by further elements between the support and the mounting point. For the purposes of the invention, the mounting point is not necessarily a point in the strict sense, but can have a certain extent.

[0039] The holding point also defines the point or area where any parasitic forces and / or moments are introduced into the optical element.

[0040] The support provides a preferably stationary base for holding or supporting the optical element. In addition to the rod leg and the ankle joint, the support of the device may optionally include further elements or components. The support may form a bipod leg or be part of a bipod.

[0041] The rod leg is preferably designed and configured to transmit forces primarily along its longitudinal axis or direction. The rod leg is typically elongated. It can be designed as a rod or bar. Preferably, the rod leg is rigid, particularly in the axial or longitudinal direction.

[0042] According to the invention, the ankle joint assembly has at least two joints, in particular the support joint and the transverse joint. The support joint and the transverse joint are preferably oriented differently. In addition to the support joint and the transverse joint, the ankle joint assembly may optionally have further joints.

[0043] The support joint can, in particular, provide support, preferably by connecting the rod leg directly or indirectly to the solid surface. The transverse joint can allow lateral displacement of the rod leg, or a lateral displacement of the lower part of the rod leg can be initiated via the transverse joint. This prevents parasitic forces and / or moments and thus reduces unwanted deformations of the optical element.

[0044] When two devices according to the invention are used together in a bipod or a holding device, it is preferably provided that the support joint and / or the transverse joint is bendable or deflectable at least in one plane spanned by the two devices.

[0045] The support joint and / or the transverse joint can also have several sub-joints or joint elements. The joints or sub-joints, in particular the support joint and / or the transverse joint, can be, for example, solid joints, especially leaf springs. Solid joints have the particular advantage of exhibiting no or negligible bearing play and generating little or no wear. However, the joints or sub-joints can also be other types of joints, such as wire joints.

[0046] The support base can be part of a bracket or frame for the optical element. The support base can be connected to the bracket or frame, or its respective components, by a force-fit and / or form-fit connection. The support base can also be formed integrally with the bracket or frame, or its respective components.

[0047] Preferably, the support foot is arranged at a lower end of the rod leg facing away from the holding point, with further elements being arranged between the support foot and the lower end of the rod leg.

[0048] The support foot preferably serves to connect the device to the solid ground. The ankle joint, i.e., at least one element of the ankle joint, connects the lower end of the rod leg to the support foot via a pivot. For this purpose, the ankle joint may be arranged, at least partially, between the lower end of the rod leg and the support foot. This means, in particular, that at least one component, especially a joint, of the ankle joint is arranged between the lower end of the rod leg and the support foot. Specifically, the support joint of the ankle joint is arranged between the lower end of the rod leg and the support foot.

[0049] The "direct" connection of the lower end of the rod leg to the support foot via the support joint is to be understood as meaning that, apart from the support joint, no further element, in particular no lever mechanism such as an adjusting lever, is arranged or interposed between the lower end of the rod leg and the support foot. It is a direct connection of the lower end of the rod leg to the support foot by means of the support joint, which functions specifically as a connecting piece.

[0050] This direct connection between the rod leg and the support base allows, at least in part, the direct transfer of forces acting at the mounting point via the rod leg and the support joint to the support base. This results in a stiffer connection of the optical element to its surroundings, helping to prevent vibration excitation, among other things.

[0051] It has proven particularly suitable if the support joint and the transverse joint are aligned at least approximately at a right angle to each other in a rest position of the device.

[0052] This further reduces the forces required to adjust the rod leg.

[0053] In other words, the support joint and the transverse joint are preferably oriented or aligned relative to each other in such a way that the support joint and the transverse joint are perpendicular to each other.

[0054] An approximately right angle can in particular be an angle between 80° and 100°, preferably an angle between 85° and 95°, more preferably an angle between 88° and 92°, and most preferably an angle of 90°.

[0055] If the optical element or the optical surface of the optical element is oriented at least approximately horizontally and the device is in its rest position, the support joint of the ankle joint preferably runs at least approximately perpendicularly and the transverse joint of the ankle joint preferably at least approximately horizontally. As a rule, neither the support joint nor the transverse joint extends along the length of the rod leg. However, the invention is not limited to the horizontal orientation of the optical element, nor to a vertical orientation of the support joint and / or a horizontal orientation of the transverse joint.

[0056] The rest position or default position of the device corresponds to a state in which the device, in particular the ankle joint or support joint and / or the transverse joint, is not deflected; that is, at least approximately, no restoring forces act on the ankle joint or the support joint and / or the transverse joint. In such a state, the support joint and the transverse joint are preferably aligned at least approximately at a right angle or 90-degree angle to each other. This is particularly independent of how the optical element itself is oriented in space, for example, whether it is vertically oriented, suspended, or has an oblique orientation in space.

[0057] In the rest position of the device, it can preferably be provided that the support joint runs or is aligned at least approximately perpendicular or at a right angle to the optical element or optical surface and / or that the transverse joint runs or is aligned at least approximately parallel to the optical element or optical surface.

[0058] Within the scope of this invention, the alignment of a joint, for example a support joint or a transverse joint, can be understood as the axis through the joint in its rest position. Using the example of a joint designed as a leaf spring, the axis corresponds to the line connecting the two ends of the leaf spring or to the orientation of the leaf spring in its relaxed or undisplaced state.

[0059] The deflection of a joint generates restoring forces. If a joint is not deflected, or if no restoring forces are acting, the joint is in its rest position. The rest position of the device requires, in particular, that both the support joint and the transverse joint are in their respective rest positions.

[0060] Within the scope of this invention, the deflection of a joint, for example the support joint or the transverse joint, can be understood to mean, for example, a tilting or bending of the joint. The deflection of the joint can, in particular, occur perpendicular to the axis of the joint. A virtual intersection point of the imaginary extensions of the support joint and the transverse joint can be considered the virtual pivot point of the ankle joint assembly, as described in more detail below.

[0061] Depending on the joint's structure, its displacement results in one or more restoring forces that work to return the joint to its original, or resting, position. These restoring forces oppose the displacement. A joint displacement can generate multiple restoring forces, particularly if the joint comprises several sub-joints and several of these sub-joints are displaced during the movement.

[0062] A deflection of the ankle joint, the support joint, and / or the transverse joint from their respective rest positions can also displace the rod leg from its rest position; for example, the rod leg can be shifted and / or tilted. The deflection of the ankle joint, the support joint, and / or the transverse joint can also result from a deflection, shift, and / or tilt of the rod leg.

[0063] The ankle joint, the support joint and / or the transverse joint or the rod leg can be deflected, moved and / or tilted, particularly by a targeted or guided movement of the optical element, to achieve its positioning and / or alignment. This can be done, for example, using actuators.

[0064] It can preferably be provided that the rod leg can be tilted about a virtual intersection point of extensions of an axis of the support joint and an axis of the transverse joint, imagined in a rest position of the device.

[0065] The virtual intersection point can be understood in particular as the virtual pivot point, or rotational pole, or instantaneous rotational pole of the rod leg. The necessary mobility for this is made possible by the ankle joint mechanism.

[0066] A particularly advantageous embodiment of the invention is one in which an adjusting lever is provided, wherein the lower end of the rod leg is operatively connected to the support foot via the adjusting lever, and wherein the transverse joint pivotally connects the lower end of the rod leg to the adjusting lever.

[0067] The actuating lever can preferably be designed as a lever or lever arm or lever device.

[0068] Preferably, the transverse joint engages with, or is preferably fixed to, a short side or end face of the actuating lever facing the support. Alternatively or additionally, the transverse joint and the actuating lever preferably run parallel to each other in the rest position of the device or in their respective rest positions.

[0069] The actuating lever and the support foot can also be articulated, preferably on a short side or an end face of the actuating lever which is opposite the side with the transverse joint.

[0070] Preferably, the support joint, the transverse joint and the actuating lever are arranged and designed such that the actuating lever can be tilted relative to a rest position of the device in order to reduce deformations of the optical element when moving the holding point by actuating the actuating lever by means of the interaction of the support joint, the transverse joint and the actuating lever, in order to counteract a tilting of the holding point relative to the optical element.

[0071] The support joint, the transverse joint, and the adjusting lever can each perform counter-tilting movements or counter-bending movements when the holding point is moved to position the optical element, and in combination reduce parasitic loads, especially parasitic bending moments, preferably at least approximately counteracting or compensating for them. The adjusting lever, in conjunction with the transverse and support joints, can thus help prevent unwanted deformations of the optical element by minimizing parasitic forces and moments acting on it.

[0072] By using an adjusting lever with a certain reduction ratio, the force required to adjust the device or optical element, or to move the carrier, can be reduced while maintaining the same effect. Furthermore, the accuracy of the adjustability, which is limited in particular by the resolution or step size of an actuator used for adjustment, can be improved, and especially refined, by means of the adjusting lever.

[0073] A reduction ratio of 5:1 to 30:1, preferably 10:1 to 20:1, has proven particularly suitable. The reduction ratio can therefore be, for example, 12:1, 15:1 or 20:1, but it can also take on other values.

[0074] The side lengths of the adjusting lever result from the desired reduction ratio, which in turn may depend on the weight of the optical element to be adjusted and / or on the strength and resolution of an actuator used for this purpose.

[0075] To fulfill its lever function, it is advantageous if the lever is significantly longer in one spatial direction than in a spatial direction perpendicular to it. For example, if the short side measures 2 mm, the length of the long side could be approximately 30 mm.

[0076] It can be advantageous if the actuating lever, especially in the direction of its longer side, is as stiff or rigid as possible.

[0077] It has proven advantageous if the carrier can be moved by an actuator, preferably fixed to the base of the carrier, for targeted positioning and / or alignment of the optical element.

[0078] This also makes the device advantageously suitable for positioning and / or aligning optical elements under minimal parasitic loads or for moving them in a guided manner.

[0079] The actuator can also be formed as a single piece with the support base.

[0080] The actuator is preferably designed to move or shift the support, in particular by acting indirectly on the lower end of the rod leg, for example via the actuating lever. Furthermore, the actuator is preferably movable or shiftable in several spatial directions, and particularly preferably in any direction.

[0081] The actuator is preferably operatively connected to the lower end of the rod leg.

[0082] Preferably, an actuator joint is provided to connect the actuating lever to the actuator in a pivotable manner.

[0083] Preferably, the actuator joint engages or is preferably fixed to a short side facing the actuator or an end face of the actuating lever that is opposite the side with the transverse joint.

[0084] The lower end of the rod leg can preferably be connected to the support foot via the transverse joint, the adjusting lever, the actuator joint and the actuator.

[0085] The actuator joint and the transverse joint can preferably run orthogonally to each other in the rest position of the device or in their respective rest positions.

[0086] When two devices according to the invention are used together in a bipod or a holding device, it is preferably provided that the actuator joint is bendable or deflectable at least in one plane spanned by the two devices.

[0087] It has proven particularly suitable if the actuator is adjustable at least approximately parallel to the support joint with respect to a rest position of the device, wherein the actuator is movably connected to the lower end of the rod leg via the adjusting lever in such a way that by extending or retracting the actuator the lower end of the rod leg can be displaced at least approximately parallel to the transverse joint with respect to the rest position.

[0088] It should be noted that the support joint and the transverse joint do not necessarily have to be in their rest positions during the extension or retraction of the actuator. The actuator's adjustment path is, in particular, at least approximately parallel to the hypothetical rest position of the support joint, i.e., to an imaginary axis that the support joint would assume if the device were in its rest position. The displacement path of the lower end of the rod leg is, in particular, at least approximately parallel to the hypothetical rest position of the transverse joint, i.e., to an imaginary axis that the transverse joint would assume if the device were in its rest position. When the actuator is adjusted, the support joint and / or the transverse joint are typically deflected, i.e., the device is not in its rest position.

[0089] If the optical element or optical surface is horizontally oriented, it may in particular be provided that the actuator is adjustable in an at least approximately perpendicular or vertical direction, wherein the lower end of the rod leg can be displaced in an at least approximately horizontal direction by extending or retracting the actuator.

[0090] When the actuator is adjusted, the adjusting lever, which is preferably connected to the actuator via the actuator joint, can tilt. This induces a translational or transverse movement of the lower end of the rod leg relative to the support base, whereby the lower end of the rod leg can exhibit a displacement component in the transverse direction and a displacement component in the longitudinal direction of the rod leg. The induced transverse movement of the lower end of the rod leg can preferably be at least approximately parallel to the optical element. If the optical element is horizontally oriented or aligned, the lower end of the rod leg can be displaced, in particular, horizontally.

[0091] The bending moment generated by the transverse movement can at least partially, preferably at least approximately, compensate for the bending moment of a passively deformed rod leg of another device fixed to the optical element, so that the optical element experiences no or hardly any deformations due to parasitic bending moments.

[0092] Preferably, a lever joint is provided to connect the adjusting lever to the support foot in a pivotable manner.

[0093] Preferably, the lever joint engages or is preferably fixed to the short side or end face of the actuating lever facing the support, in particular the side on which the transverse joint is also fixed.

[0094] The lever joint and the transverse joint can preferably run approximately parallel to each other in the rest position of the device or in their respective rest positions.

[0095] When two devices according to the invention are used together in a bipod or a holding device, it is preferably provided that the lever joint is bendable or deflectable at least in one plane spanned by the two devices.

[0096] It can be advantageous if the actuating lever is at least partially arranged between the ankle joint assembly and the actuator, with the actuating lever being articulated to the lower end of the rod leg via the transverse joint, to the support foot via the lever joint and / or to the actuator via the actuator joint.

[0097] The support joint connects the lower end of the support leg to a first connection point of the support foot, which preferably lies on an imaginary extension of the support joint's axis relative to the rest position of the device or the support joint. The transverse joint, on the other hand, connects the lower end of the support leg to a second connection point via the adjusting lever, the actuator joint, and the actuator, and to a third connection point of the support foot via the adjusting lever and the lever joint, neither of which lies on an imaginary extension of the transverse joint's axis relative to the rest position of the device or the transverse joint.

[0098] It can be advantageous if the rod legs are rigid, especially in the axial direction.

[0099] The legs of the rods are at least partially or sectionally rigid.

[0100] The legs of the rods can be made of steel, especially corrosion-resistant or stainless steel, other metals or ceramics.

[0101] It can be advantageous if the cross-section of the rod legs is round, square, or rectangular.

[0102] This results in high stiffness in the rod direction or in the longitudinal direction of the device, which has a beneficial effect on the holding properties of the device.

[0103] It can also be advantageous if the rod legs are flexible, especially in the radial or transverse direction.

[0104] The legs of the rods are at least partially or section by section flexible.

[0105] In particular, it can also be advantageous for the rod legs to be rigid in some sections and flexible in others. Specifically, the flexible sections can provide a degree of mobility similar to a hinge mechanism.

[0106] In a preferred embodiment, the rod legs are between 50 mm and 300 mm long, particularly preferably between 100 mm and 150 mm.

[0107] It may be provided that the support joint, the transverse joint, the lever joint and / or the actuator joint is designed as a wire joint and / or has at least one wire joint.

[0108] It may preferably be provided that the support joint, the transverse joint, the lever joint and / or the actuator joint is designed as a leaf spring joint and / or has at least one leaf spring joint.

[0109] It has proven advantageous if the support joint, the transverse joint, the lever joint and / or the actuator joint has at least two joint elements arranged axially offset from each other and oriented 90° rotated relative to each other.

[0110] It can be provided, in particular, that the joint elements have a common axis. The joint elements can preferably be arranged on two adjacent planes of their common axis, offset from each other axially.

[0111] In a further development of the invention, a head joint device can be provided, wherein the head joint device is arranged between the holding point and an upper end of the rod leg facing the holding point.

[0112] The head joint device can connect the carrier to the anchor point.

[0113] Furthermore, the head joint device preferably provides tilting mobility of the device at the holding point.

[0114] It has proven particularly suitable if the joint head is located directly at the holding point. In particular, the joint head can preferably be located as close as possible to the holding point, so that no other elements are in between.

[0115] The ankle joint, the support joint, the transverse joint, the lever joint, the actuator joint and / or the head joint may each have at least one joint or joint element.

[0116] Preferably, the at least one joint element is a leaf spring or a leaf spring joint.

[0117] The advantages of leaf spring joints lie in their comparatively high stiffness along the joint axis, the absence of bearing play, and negligible hysteresis in the elastic deformation range. However, the joint element can also be a wire joint or another type of joint. A wire joint can be advantageous for simultaneous bending around multiple axes.

[0118] Preferably, the ankle joint, support joint, transverse joint, lever joint, actuator joint and / or head joint can have a plurality of joint elements, the joint elements preferably being designed as leaf springs.

[0119] The joint elements can be arranged in different planes when viewed along the axis of the respective joint. In particular, the joint elements can be arranged and designed such that the joint element(s) arranged in a first plane allow deflection in a first direction, and the joint element(s) arranged in a second plane allow deflection in a second direction orthogonal to the first. Both directions lie within a single plane, which is preferably orthogonal to the axis of the joint. Joint elements on the same plane are preferably oriented in the same way and not rotated relative to each other. Intermediate elements can be provided between the planes.

[0120] The joints with the majority of joint elements can be at least partially monolithic or one-piece, and possibly also monolithic or one-piece with the rod leg.

[0121] Further preferred embodiments and uses of the device according to the invention will become apparent from the following description of the further subject matter of the invention.

[0122] The present invention also relates to a holding device for holding an optical element, in particular an optical element of a mask inspection system or a lithography system, comprising at least a first device according to the invention and a second device according to the invention, wherein the first device and the second device converge towards each other in the direction of a common holding point on the optical element.

[0123] The holding device can also be, or be referred to as, a bipod.

[0124] The first and second devices are, in particular, devices with one or more features as described above. The advantages are analogous to those already described.

[0125] It is specifically provided that the first and the second device each have an ankle joint device with a support joint and a transverse joint, wherein the respective support joint connects a lower end of a respective rod leg directly to the support foot in a pivotal manner.

[0126] It has proven advantageous if the respective connection of the lower end of the rod leg with the support foot is articulated at least in one plane spanned by the two devices, i.e., that the support joint is preferably bendable or deflectable at least in this plane.

[0127] The first device and the second device converge towards each other in a V-shape at an angle in the direction of the optical element.

[0128] A gap can remain between the first device and the second device, or between virtual extensions of the first and second devices, at the level of the common holding point. The common holding point can, in particular, be designed as a common bracket or holding device.

[0129] It can be advantageous if the first device and the second device form at least an approximate right angle to each other.

[0130] The first and second devices are arranged at an approximate right angle to each other. Preferably, the longitudinal axes of the respective legs of the two devices are at an approximate right angle to each other.

[0131] This ensures the highest possible stability of the holding device or bipod. Furthermore, the right angle prevents feedback between the devices during movement, for example, during a displacement actively induced by an actuator.

[0132] In this context, an approximately right angle can be, in particular, an angle between 80° and 100°, preferably an angle between 85° and 95°, more preferably an angle between 88° and 92°, and most preferably an angle of exactly 90°.

[0133] The plane of the holding device, formed by the V-shape of the first and second devices converging at an angle, is preferably perpendicular to the optical element or the optical surface of the optical element. However, the plane of the holding device can also be oriented differently.

[0134] It has proven advantageous to provide an actuating lever of the first device and an actuating lever of the second device, wherein the support joint of the first device, the support joint of the second device, the transverse joint of the first device, the transverse joint of the second device, the actuating lever of the first device and the actuating lever of the second device are arranged and designed such that the actuating lever of the first device or of the second device can be tilted relative to a respective rest position of the first device or of the second device in order to reduce deformations of the optical element by means of the interaction of the support joints, the transverse joints and the actuating levers, in order to counteract a tilting of the holding point relative to the optical element when moving the holding point by actuating one or both actuating levers.

[0135] In the respective device, it is preferably provided that the lower end of the rod leg is operatively connected to the support foot via the adjusting lever, with the transverse joint connecting the lower end of the rod leg pivotally to the adjusting lever.

[0136] It has proven advantageous if the respective connection of the lower end of the rod leg with the adjusting lever is articulated at least in one plane spanned by the two devices, i.e., that the transverse joint is preferably bendable or deflectable at least in this plane.

[0137] The actuating lever of the first or second device can preferably be designed as a lever, lever arm, or lever assembly. It can be advantageous if the respective actuating lever is as stiff or rigid as possible, particularly along its longer side. To fulfill its lever function, the respective actuating lever preferably has a transmission ratio, or in this case, preferably a reduction ratio (greater movement at the lever input and smaller movement at the lever output).

[0138] In an advantageous further development of the invention, it may be provided that an actuator of the first device for targeted positioning and / or alignment of the optical element is arranged and designed in such a way as to move a carrier of the first device, and / or an actuator of the second device for targeted positioning and / or alignment of the optical element is arranged and designed in such a way as to move a carrier of the second device.

[0139] In this further development, at least one of the two devices has an actuator. In particular, the first device and / or the second device can have an actuator. Preferably, both the first support and the second support are movable or displaceable.

[0140] Preferably, the actuator of the first device and / or the actuator of the second device is adjustable at least approximately parallel to the respective support joint with respect to a rest position of the respective device, wherein the actuator of the respective device is movably connected to the lower end of the respective rod leg in such a way that by extending or retracting the respective actuator, the lower end of the respective rod leg can be displaced at least approximately parallel to the respective transverse joint with respect to the rest position.

[0141] The actuator can preferably be articulated to the lower end of the rod leg via the actuating lever and an actuator joint of the respective device.

[0142] It has proven advantageous if the respective connection of the lower end of the rod leg with the actuator is articulated at least in one plane spanned by the two devices, i.e., that the actuator joint is preferably bendable or deflectable at least in this plane.

[0143] Furthermore, the lower end of the rod leg of the first or second device can preferably be connected to the support foot via the transverse joint, the adjusting lever, the actuator joint and the actuator.

[0144] Preferably, the actuating lever of the respective device is articulated to the support foot via a lever joint.

[0145] It has proven advantageous if the respective connection of the actuating lever with the support foot is articulated at least in one plane spanned by the two devices, i.e., that the lever joint is preferably bendable or deflectable at least in this plane.

[0146] It may be provided that a support foot of the first device is formed integrally with a support foot of the second device.

[0147] In other words, the respective support base of the first and second devices can be part of a common base, bracket, or frame. Instead of a common support base, the lower ends of the rod legs or the elements attached to them can also be connected to a common surface in the surrounding area or directly to the solid ground.

[0148] The present invention also relates to an arrangement for holding an optical element, in particular an optical element of a mask inspection system or a lithography system, comprising at least six devices or three holding devices according to the invention.

[0149] The arrangement according to the invention can also be particularly suitable for positioning and / or aligning the optical element.

[0150] The devices or holding devices are, in particular, devices or holding devices with one or more features as described above. The advantages are analogous to those already described.

[0151] Preferably, the arrangement comprises exactly six devices according to the invention or exactly three holding devices according to the invention. As a rule, this sufficiently defines all degrees of freedom for positioning and / or aligning an optical element, particularly if this is provided in addition to the holding function.

[0152] Mixtures of devices and holding devices are possible, in particular such that a total of preferably exactly six devices are present, wherein optionally two devices can each form a holding device.

[0153] According to the invention, it can also be provided, in particular, that the arrangement comprises, for example, four devices according to the invention and one holding device according to the invention, wherein the holding device comprises two of the six devices provided. Further combinations are possible analogously.

[0154] It should be noted that if there are more than six devices, more than three holding devices may be formed by the devices.

[0155] The combination of at least six devices or three holding devices ensures stable support for the optical element while simultaneously allowing for the utilization of degrees of freedom for optional positioning and / or alignment of the optical element. The combination of exactly six devices or exactly three holding devices into a hexapod has proven particularly advantageous.

[0156] It can be advantageous if the devices and / or the holding devices are arranged at least approximately uniformly around an outer edge region of the optical element. This increases the stability of the arrangement.

[0157] The devices and / or holding devices are to be considered as being arranged at least approximately uniformly distributed on the outer edge region of the optical element, in particular if the respective position of the devices and / or holding devices deviates by no more than 10%, preferably no more than 5%, and more preferably no more than 2% from their position in the case of a completely uniform distribution.

[0158] The holding devices can be oriented such that the V-shaped plane formed by the first and second devices, which converge at an angle, is tangential to an edge of the optical element. However, the planes of the holding devices can also be oriented differently.

[0159] The present invention further relates to a system comprising an optical element, in particular an optical element of a mask inspection system or a lithography system, and comprising at least six devices according to the invention or three holding devices according to the invention for holding the optical element.

[0160] This may also include, in particular, the positioning and / or alignment of the optical element.

[0161] The devices or holding devices are, in particular, devices or holding devices with one or more features as described above. The advantages are analogous to those already described.

[0162] The number and arrangement of the device or holding device according to the invention within the system can preferably be selected as already described with regard to the arrangement according to the invention. It is particularly suitable if the system according to the invention has six devices or three holding devices. Optionally, two devices can each form one holding device.

[0163] The optical element may be a mirror or a lens. In particular, it may be a mirror or a lens of a lithography system.

[0164] The present invention also relates to a method for holding and, in particular, for positioning and / or aligning an optical element, in particular an optical element of a mask inspection system or a lithography system, wherein the optical element is held and, in particular, positioned and / or aligned with at least one device and / or holding device or arrangement according to the invention.

[0165] The devices, holding devices, or arrangements are, in particular, devices, holding devices, or arrangements with one or more features as described above. The advantages are analogous to those already described.

[0166] The present invention further relates to a mask inspection system for inspecting a photomask, in particular a reticle for a projection exposure system, comprising an illumination device with a radiation source and optics comprising at least one optical element, and a detection device, wherein the optical element is held by at least one device and / or a holding device or arrangement according to the invention.

[0167] The at least one optical element can in particular also be positioned and / or aligned by at least one device and / or holding device or arrangement according to the invention.

[0168] The devices, holding devices, or arrangements are, in particular, devices, holding devices, or arrangements with one or more features as described above. The advantages are analogous to those already described.

[0169] The mask inspection system can be used, in particular, to inspect and measure photomasks or reticles before their intended use or integration into an optical system, especially a lithography system, and especially to verify the image quality. This can optionally be part of the photomask manufacturing process and preferably contribute to quality assurance.

[0170] Photomasks are projection templates used for photolithographic structuring in the production of semiconductor devices. They allow for the selective exposure of only specific areas of a photoresist or resist applied to the substrate or wafer to be structured. Analogous to their English name, photomasks are also referred to as reticles in German.

[0171] Lithography systems, as described in more detail below, can be, in particular, projection exposure systems for semiconductor lithography using EUV (extreme ultraviolet) light and / or DUV (deep ultraviolet) light. In a particularly preferred embodiment, the lithography system can be an EUV projection exposure system, wherein the reticle to be inspected is preferably designed as an EUV mask. However, the mask inspection system according to the invention is not limited to use in EUV lithography. It can also be particularly suitable for other photomasks that are not EUV masks.

[0172] EUV masks are specifically tuned to a working wavelength in the EUV range, preferably to a working wavelength of 5 nm to 30 nm, more preferably from 10 nm to 15 nm, and particularly preferably from 13.5 nm. These are generally reflective photomasks that function as interference mirrors using multilayer layer arrangements or coatings.

[0173] Photomasks must be manufactured with high precision, as mask defects on the order of 1 nm, for example in EUV lithography, can lead to significant losses in image quality and thus in the quality of the generated structures. Therefore, mask inspection systems are typically used to check photomasks, in order to locate and, if necessary, identify mask defects of the relevant size. An exemplary mask inspection system for EUV masks, as well as a mask inspection method, is known from DE 10 2012 213 794 A1 of the applicant.

[0174] To ensure high measurement accuracy of the mask inspection system, it is advantageous if the optical elements of the mask inspection system are held as stably and without vibration as possible, and if necessary, positioned and / or aligned, whereby deformations of the optical elements must be avoided in particular. This can be achieved in a particularly advantageous manner by the mask inspection system according to the invention.

[0175] The illumination device of the mask inspection system serves to illuminate the photomask to be inspected with a measuring radiation, whereby the detection device detects the pattern produced by the illuminated photomask.

[0176] The wavelength of the measuring radiation emitted by the radiation source of the illumination device preferably corresponds to the operating wavelength of the lithography system for which the photomask to be inspected is intended. The optics of the illumination device comprise at least one optical element, which is configured according to the invention. With the aid of the optics, the measuring radiation can, for example, be guided along a specific beam path and thereby shaped as desired, for example, focused.

[0177] Preferably, in addition to the illumination device and the detection device, the mask inspection system includes a magnification device for magnifying the image of the pattern produced by the photomask, a mask holding device for holding the photomask and / or an evaluation device.

[0178] The present invention further relates to a lithography system, in particular a projection exposure system for semiconductor lithography, with an illumination system comprising a radiation source and optics, which has at least one optical element, wherein the optical element is held by at least one device and / or a holding device or arrangement according to the invention.

[0179] The optical element can in particular also be positioned and / or aligned by at least one device and / or holding device or arrangement according to the invention.

[0180] The devices, holding devices, or arrangements are, in particular, devices, holding devices, or arrangements with one or more features as described above. The advantages are analogous to those already described.

[0181] Lithography systems can be, in particular, projection exposure systems for semiconductor lithography using EUV (extreme ultraviolet) light and / or DUV (deep ultraviolet) light.

[0182] In these and related application areas, a stable or wobble-free mounting, as well as, if necessary, a stable or wobble-free positioning and exact alignment of optical elements and the simultaneous avoidance of deformations of the optical elements are of particular importance in order to achieve high image quality without image defects and thus to be able to produce high-quality structures, especially semiconductor structures.

[0183] Furthermore, it can be advantageous if a reticle or photomask of the lithography system is inspected, examined, or measured for quality and imaging properties using a mask inspection system according to the invention before use or integration into the lithography system.

[0184] Analogous to the mask inspection system and the lithography system according to the invention, the device, the holding device, the arrangement, the system, and the method according to the invention can be applied just as advantageously in other optical systems. This applies in particular to all optical systems with high precision requirements.

[0185] Features described in connection with one of the subject matter of the invention, in particular the device, holding device, arrangement, system, method, mask inspection system, or lithography system according to the invention, can also be advantageously implemented for the other subject matter of the invention. Likewise, advantages mentioned in connection with one of the subject matter of the invention can also be understood as relating to the other subject matter of the invention.

[0186] It should also be noted that terms such as "comprehensive," "exhibiting," or "with" do not exclude other characteristics or steps. Furthermore, terms such as "a" or "that," which indicate a singular number of steps or characteristics, do not exclude a plurality of characteristics or steps—and vice versa.

[0187] In a purist embodiment of the invention, however, it may also be provided that the features introduced in the invention with the terms "comprising," "comprising," or "with" are exhaustively listed. Accordingly, one or more lists of features within the scope of the invention may be considered complete, for example, for each claim. The invention may, for instance, consist exclusively of the features mentioned in claim 1.

[0188] It should be noted that designations such as "first" or "second" etc. are primarily used for the purpose of distinguishing between the respective device or process features and are not necessarily intended to indicate that features are mutually dependent or related to each other.

[0189] Exemplary embodiments of the invention are described in more detail below with reference to the drawing.

[0190] The figures each show preferred embodiments in which individual features of the present invention are combined with one another. Features of an embodiment can also be implemented independently of the other features of the same embodiment and can therefore be readily combined by a person skilled in the art to form further meaningful combinations and subcombinations with features of other embodiments.

[0191] In the figures, functionally identical elements are provided with the same reference symbols.

[0192] They show: Fig. 1 an EUV projection exposure system in meridional section; Fig. 2 a DUV projection exposure system; Fig. 3 a schematic representation of an embodiment of the device according to the invention and of the holding device according to the invention for holding an optical element in a rest position; Fig. 4. Another basic representation according to the Fig. 3 during active deflection; Fig. 5 another basic representation according to the Fig. 3 in case of passive deflection; Fig. 6. A schematic view of an exemplary joint with two joint elements; and Fig. 7 a schematic representation of an embodiment of the arrangement and system according to the invention for holding an optical element.

[0193] The following will first refer to Fig. 1. The essential components of an EUV projection exposure system 100 for microlithography are described as an example of a lithography system. The description of the basic structure of the EUV projection exposure system 100 and its components is not intended to be restrictive.

[0194] An illumination system 101 of the EUV projection exposure system 100 comprises, in addition to a radiation source 102, an illumination optic 103 for illuminating an object field 104 in an object plane 105. A reticule 106 arranged in the object field 104 is exposed. The reticule 106 is held by a reticule holder 107. The reticule holder 107 can be moved, particularly in a scanning direction, by means of a reticule displacement drive 108.

[0195] In Fig. Figure 1 shows a Cartesian xyz coordinate system for illustrative purposes. The x-direction runs perpendicular to the plane of the drawing. The y-direction runs horizontally, and the z-direction runs vertically. The scan direction runs in Fig. 1 along the y-direction. The z-direction runs perpendicular to the object plane 105.

[0196] The EUV projection exposure system 100 comprises a projection optic 109. The projection optic 109 serves to image the object field 104 onto an image field 110 in an image plane 111. The image plane 111 is parallel to the object plane 105. Alternatively, an angle other than 0° between the object plane 105 and the image plane 111 is also possible.

[0197] A structure on the reticulum 106 is imaged onto a photosensitive layer of a wafer 112 located in the image plane 111 within the image field 110. The wafer 112 is held by a wafer holder 113. The wafer holder 113 can be displaced, particularly along the y-direction, via a wafer transfer drive 114. The displacement of the reticulum 106 via the reticulum transfer drive 108 and of the wafer 112 via the wafer transfer drive 114 can be synchronized.

[0198] Radiation source 102 is an EUV radiation source. Specifically, radiation source 102 emits EUV radiation 115, which is also referred to as useful radiation or illumination radiation. The useful radiation 115 has a wavelength in the range between 5 nm and 30 nm. Radiation source 102 can be a plasma source, for example, an LPP source (laser-produced plasma) or a DPP source (gas-discharged produced plasma). It can also be a synchrotron-based radiation source. Radiation source 102 can be a free-electron laser (FEL).

[0199] The illumination radiation 115, emanating from the radiation source 102, is focused by a collector 116. The collector 116 can be a collector with one or more ellipsoidal and / or hyperboloid reflective surfaces. The at least one reflective surface of the collector 116 can be illuminated with the illumination radiation 115 at grazing incidence (GI), i.e., with angles of incidence greater than 45°, or at normal incidence (NI), i.e., with angles of incidence less than 45°. The collector 116 can be structured and / or coated, both to optimize its reflectivity for the useful radiation 115 and to suppress stray light.

[0200] After the collector 116, the illumination radiation 115 propagates through an intermediate focus in an intermediate focal plane 117. The intermediate focal plane 117 can represent a separation between a radiation source module, comprising the radiation source 102 and the collector 116, and the illumination optics 103.

[0201] The illumination optics 103 comprise a deflecting mirror 118 and, downstream in the beam path, a first faceted mirror 119. The deflecting mirror 118 can be a planar deflecting mirror or, alternatively, a mirror with an effect that influences the beam shape beyond the mere deflection effect. Alternatively or additionally, the deflecting mirror 118 can be designed as a spectral filter that separates a useful wavelength of the illumination radiation 115 from stray light of a different wavelength. If the first faceted mirror 119 is arranged in a plane of the illumination optics 103 that is optically conjugate to the object plane 105 as the field plane, it is also referred to as a field faceted mirror. The first faceted mirror 119 comprises a plurality of individual first facets 120, which are also referred to as field facets in the following. Of these facets 120, the following are in the Fig. 1 only some examples are shown.

[0202] The first facets 120 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or semicircular border contour. The first facets 120 can be designed as planar facets or alternatively as convexly or concavely curved facets.

[0203] As is known, for example, from DE 10 2008 009 600 A1, the first facets 120 can themselves each be composed of a plurality of individual mirrors, in particular a plurality of micromirrors. The first facet mirror 119 can in particular be designed as a microelectromechanical system (MEMS system). For details, reference is made to DE 10 2008 009 600 A1.

[0204] Between the collector 116 and the deflecting mirror 118, the illumination radiation 115 runs horizontally, i.e. along the y-direction.

[0205] In the beam path of the illumination optics 103, a second faceted mirror 121 is arranged downstream of the first faceted mirror 119. If the second faceted mirror 121 is arranged in a pupil plane of the illumination optics 103, it is also referred to as a pupil faceted mirror. The second faceted mirror 121 can also be arranged at a distance from a pupil plane of the illumination optics 103. In this case, the combination of the first faceted mirror 119 and the second faceted mirror 121 is also referred to as a specular reflector. Specular reflectors are known from US 2006 / 0132747 A1, EP 1 614 008 B1, and US 6,573,978.

[0206] The second facet mirror 121 comprises a plurality of second facets 122. In the case of a pupil facet mirror, the second facets 122 are also referred to as pupil facets.

[0207] The second facets 122 can also be macroscopic facets, which may, for example, have round, rectangular, or hexagonal edges, or alternatively, facets composed of micromirrors. Reference is also made to DE 10 2008 009 600 A1 in this regard.

[0208] The second facets 122 can have planar or alternatively convex or concave curved reflective surfaces.

[0209] The illumination optics 103 thus form a double-faceted system. This basic principle is also known as a fly's eye integrator.

[0210] It may be advantageous not to arrange the second faceted mirror 121 exactly in a plane which is optically conjugate to a pupil plane of the projection optics 109.

[0211] With the aid of the second faceted mirror 121, the individual first facets 120 are imaged into the object field 104. The second faceted mirror 121 is the last beam-shaping, or indeed the last, mirror for the illumination radiation 115 in the beam path before the object field 104.

[0212] In another embodiment of the illumination optics 103, not shown, a transmission optic can be arranged in the beam path between the second facet mirror 121 and the object field 104, which contributes in particular to imaging the first facets 120 into the object field 104. 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 103. 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 (GI mirrors, "grazing incidence" mirrors).

[0213] The lighting optic 103, in the version that is in the Fig. Figure 1 shows exactly three mirrors after the collector 116, namely the deflecting mirror 118, the field facet mirror 119 and the pupil facet mirror 121.

[0214] In a further embodiment of the lighting optics 103, the deflecting mirror 118 can also be omitted, so that the lighting optics 103 can then have exactly two mirrors after the collector 116, namely the first faceted mirror 119 and the second faceted mirror 121.

[0215] The imaging of the first facets 120 by means of the second facets 122 or with the second facets 122 and a transmission optic into the object plane 105 is regularly only an approximate imaging.

[0216] The projection optics 109 comprise a plurality of mirrors Mi, which are numbered according to their arrangement in the beam path of the EUV projection exposure system 100.

[0217] In the Fig. In the example shown, the projection optics 109 comprises six mirrors M1 to M6. Alternatives with four, eight, ten, twelve, or any other number of mirrors Mi are also possible. The penultimate mirror M5 and the last mirror M6 each have an aperture for the illumination radiation 115. The projection optics 109 is a double-obscured optic. The projection optics 109 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.

[0218] 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 103, can have highly reflective coatings for the illumination radiation 115. These coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.

[0219] The projection optics 109 has a large object-image offset in the y-direction between a y-coordinate of a center of the object field 104 and a y-coordinate of the center of the image field 110. This object-image offset in the y-direction can be approximately as large as a z-distance between the object plane 105 and the image plane 111.

[0220] The number of intermediate image planes in the x- and y-directions in the beam path between the object field 104 and the image field 110 can be the same or, depending on the design of the projection optics 109, different. Examples of projection optics with different numbers of such intermediate images in the x- and y-directions are known from US 2018 / 0074303 A1.

[0221] Each of the pupil facets 122 is assigned to exactly one of the field facets 120 to form an illumination channel for illuminating the object field 104. This can result, in particular, in illumination according to Köhler's principle. The far field is divided into a multitude of object fields 104 by means of the field facets 120. The field facets 120 generate a plurality of images of the intermediate focus on the pupil facets 122 assigned to each of them.

[0222] The field facets 120 are each superimposed on the reticulum 106 by an associated pupil facet 122 to illuminate the object field 104. The illumination of the object field 104 is particularly homogeneous. It preferably exhibits a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.

[0223] The illumination of the entrance pupil of the projection optics 109 can be geometrically defined by the arrangement of the pupil facets. By selecting the illumination channels, in particular the subset of pupil facets that guide light, the intensity distribution in the entrance pupil of the projection optics 109 can be adjusted. This intensity distribution is also referred to as the illumination setting.

[0224] Another preferred pupil uniformity in the area of ​​defined illuminated sections of an illumination pupil of the illumination optics 103 can be achieved by a redistribution of the illumination channels.

[0225] Further aspects and details of the illumination of the object field 104 and, in particular, the entrance pupil of the projection optics 109 are described below.

[0226] The projection optic 109 can, in particular, have a homocentric entrance pupil. This may be accessible. It may also be inaccessible.

[0227] The entrance pupil of the projection optics 109 cannot always be illuminated exactly by the pupil facet mirror 121. When the projection optics 109 image the center of the pupil facet mirror 121 telecentrically onto the wafer 112, the aperture rays often do not intersect at a single point. However, a surface can be found where the pairwise determined separation of the aperture rays is minimized. This surface represents the entrance pupil or a surface conjugate to it in real space. In particular, this surface exhibits a finite curvature.

[0228] The projection optics 109 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 121 and the reticle 106. This optical component will allow the different positions of the tangential and sagittal entrance pupils to be taken into account.

[0229] During the Fig. In the arrangement of the components of the illumination optics 103 shown in Figure 1, the pupil facet mirror 121 is arranged in a plane conjugate to the entrance pupil of the projection optics 109. The first field facet mirror 119 is arranged tilted relative to the object plane 105. The first facet mirror 119 is arranged tilted relative to an arrangement plane defined by the deflecting mirror 118.

[0230] The first faceted mirror 119 is arranged at an angle to an arrangement plane defined by the second faceted mirror 121.

[0231] In Fig. Figure 2 shows an exemplary DUV projection exposure system 200. The DUV projection exposure system 200 comprises an illumination system 201, a device called a reticule stage 202 for receiving and precisely positioning a reticule 203, by which the subsequent structures on a wafer 204 are determined, a wafer holder 205 for holding, moving and precisely positioning the wafer 204 and an imaging device, namely a projection optic 206, with several optical elements, in particular lenses 207, which are held in a lens housing 209 of the projection optic 206 via mounts 208.

[0232] Alternatively or in addition to the lenses 207 shown, various refractive, diffractive and / or reflective optical elements, including mirrors, prisms, end plates and the like, may be provided.

[0233] The basic operating principle of the DUV projection exposure system 200 provides that the structures introduced into the reticulum 203 are imaged onto the wafer 204.

[0234] The illumination system 201 provides a projection beam 210 in the form of electromagnetic radiation, which is required for imaging the reticulum 203 onto the wafer 204. A laser, a plasma source, or the like can be used as the source of this radiation. In the illumination system 201, the radiation is shaped by optical elements such that the projection beam 210, upon striking the reticulum 203, exhibits the desired properties with regard to diameter, polarization, wavefront shape, and the like.

[0235] Using the projection beam 210, an image of the reticulum 203 is generated and transferred, appropriately reduced in size, to the wafer 204 by the projection optics 206. The reticulum 203 and the wafer 204 can be moved synchronously, so that areas of the reticulum 203 are mapped onto corresponding areas of the wafer 204 practically continuously during a so-called scan process.

[0236] Optionally, the air gap between the last lens 207 and the wafer 204 can be replaced by a liquid medium with a refractive index greater than 1.0. This liquid medium could, for example, be highly purified water. Such a setup is also known as immersion lithography and offers increased photolithographic resolution.

[0237] The use of the invention is not limited to use in projection exposure systems 100, 200, and in particular not limited to systems with the described setup. The invention is suitable for any lithography or microlithography systems, but especially for projection exposure systems with the described setup. The invention is also suitable for EUV projection exposure systems, which have a lower image-side numerical aperture than those associated with Fig. The invention is particularly suitable for EUV projection exposure systems that have an image-side numerical aperture of 0.25 to 0.5, preferably 0.3 to 0.4, and most preferably 0.33. Furthermore, the invention can also be advantageously used for optical elements of mask inspection systems for inspecting photomasks for semiconductor lithography. The invention and the following embodiments are not limited to a specific design.

[0238] The following figures represent the invention only as an example and in a highly schematic form.

[0239] The Fig. Figure 3 shows a schematic representation of an embodiment of the device 1 according to the invention for holding an optical element 2, which is located in the Fig. Figure 3 is only partially shown. The optical element 2 can, in particular, be an optical element of a mask inspection system or a lithography system. In the Fig. 3 Two devices 1 are combined to form a holding device 15, as will be described in more detail below.

[0240] The device 1 has a mounting point 3 for connection to the optical element 2, a support 4, and a support foot 5, wherein the mounting point 3 is connected to the support 4. The support 4 has at least one rod leg 6 and an ankle joint 7. The ankle joint 7 pivotally connects a lower end 6a of the rod leg 6, facing away from the mounting point 3, to the support foot 5. According to the invention, the ankle joint 7 has a support joint 7a and a transverse joint 7b, wherein the support joint 7a pivotally connects the lower end 6a of the rod leg 6 directly to the support foot 5.

[0241] In the Fig. Figure 3 shows the support joint 7a and the transverse joint 7b only schematically and in a highly simplified manner.

[0242] In the exemplary embodiment, it is preferably provided that the support joint 7a and the transverse joint 7b are oriented or aligned differently, i.e., can be deflected in different directions.

[0243] In a preferred embodiment of the invention, the support joint 7a and the transverse joint 7b are aligned at least approximately at a right angle to each other in a rest position of the device 1.

[0244] The Fig. Figure 3 shows the device 1 in its rest position, with the support joint 7a and the transverse joint 7b in their respective rest positions and thus not deflected. For a representation of the device 1 in which the support joint 7a and / or the transverse joint 7b is deflected, please refer to the following description. Fig. 4 and Fig. 5 referred.

[0245] In the exemplary embodiment according to the Fig. Figure 3 shows the optical element 2 oriented horizontally by way of example. Furthermore, the support joint 7a is oriented at least approximately vertically, i.e., orthogonally to the optical element 2, and the transverse joint 7b is oriented at least approximately horizontally, i.e., parallel to the optical element 2. However, the invention is not limited to this example.

[0246] In the exemplary embodiment, the rod leg 6 is preferably tiltable about a virtual intersection point 8 of extensions of an axis of the support joint 7a and an axis of the transverse joint 7b, imagined in a rest position of the device 1. This can be demonstrated, for example, by means of the Fig. 3 visible.

[0247] It has proven advantageous to provide an adjusting lever 9, wherein the lower end 6a of the rod leg 6 is operatively connected to the support foot 5 via the adjusting lever 9, and wherein the transverse joint 7b pivotally connects the lower end 6a of the rod leg 6 to the adjusting lever 9.

[0248] The support joint 7a, the transverse joint 7b and the actuating lever 9 are preferably arranged and designed such that the actuating lever 9 can be tilted relative to a rest position of the device 1 in order to reduce deformations of the optical element 2 when moving the holding point 3 by actuating the actuating lever 9 by means of the interaction of the support joint 7a, the transverse joint 7b and the actuating lever 9, in order to counteract a tilting of the holding point 3 relative to the optical element 2.

[0249] In a particularly suitable embodiment of the invention, the carrier 4 can be moved by an actuator 10, preferably fixed to the carrier base 5, for a targeted positioning and / or alignment of the optical element 2.

[0250] Preferably an actuator joint 11 is provided to connect the actuating lever 9 to the actuator 10 in a pivotal manner.

[0251] Preferably a lever joint 12 is provided to connect the actuating lever 9 to the support foot 5 in a pivotal manner.

[0252] It can preferably be provided that the actuator 10 is adjustable at least approximately parallel to the support joint 7a with respect to a rest position of the device 1, wherein the actuator 10 is movably connected to the lower end 6a of the rod leg 6 via the actuating lever 9 in such a way that, by extending or retracting the actuator 10 and the interaction with the lever joint 12, the actuator joint 11, the transverse joint 7b and the support joint 7a, the lower end 6a of the rod leg 6 is displaced at least approximately parallel to the transverse joint 7b with respect to the rest position.

[0253] The actuating lever 9 can be arranged at least partially between the ankle joint device 7 and the actuator 10, wherein the actuating lever 9 is pivotally connected to the lower end 6a of the rod leg 6 via the transverse joint 7b, to the support foot 5 via the lever joint 12 and / or to the actuator 10 via the actuator joint 11.

[0254] Preferably the actuating lever 9 is elongated, wherein the actuating lever 9 has short sides (or end faces) and long sides, resulting in a certain transmission ratio or, in this case, a reduction ratio.

[0255] It has proven advantageous if the transverse joint 7b and preferably the lever joint 12 are fixed to a short side (end face) of the actuating lever 9 facing the support 4, and preferably the actuator joint 11 is fixed to an opposite short side (end face) of the actuating lever facing the actuator 10. It has proven particularly suitable if the transverse joint 7b and the lever joint 12 are aligned at least approximately parallel to each other in the rest position of the device 1 and / or if the vertical joint 7a and the actuator joint 11 are aligned at least approximately parallel to each other in the rest position.

[0256] The lower end 6a of the rod leg 6 can preferably be movably connected to the support foot 5 indirectly via the transverse joint 7b, namely via the adjusting lever 9, the actuator joint 11 and the actuator 10. Furthermore, the lower end 6a of the rod leg 6 is articulated or movably connected to the support foot 5 directly via the support joint 7a.

[0257] The support joint 7a connects the lower end 6a of the support leg 6 to a first connection point of the support foot 5, which preferably lies on an imaginary extension of the support joint 7a, relative to the rest position of the device 1 or the support joint 7a. The transverse joint 7b, on the other hand, connects the lower end 6a of the support leg 6 to a second connection point via the actuating lever 9, the actuator joint 11 and the actuator 10, and to a third connection point of the support foot 5 via the actuating lever 9 and the lever joint 12, neither of which lies on an imaginary extension of the transverse joint 7b, relative to the rest position of the device 1 or the transverse joint 7b.

[0258] Based on the exemplary embodiment according to Fig. Figure 3 shows that the device 1 according to the invention creates a relatively direct force flow, compared to the prior art, from the mounting point 3 on the optical element 2 via the head joint 14, the rod leg 6, and the support joint 7a to the support base 5. In addition, there is the force flow from the mounting point 3 via the head joint 14, the rod leg 6, the transverse joint 7b, the adjusting lever, and the lever joint 12 to the support base 5, as well as the force flow from the mounting point 3 via the head joint 14, the rod leg 6, the transverse joint 7b, the adjusting lever, the actuator joint 11, and the actuator 10 to the support base 5. This direct force flow avoids the need for a stiffer connection of the optical element to the support base and thus prevents unacceptably high vibrations.

[0259] It is preferably possible for the rod legs 6 to be rigid, particularly in the axial direction. It is also possible for the rod legs 6 to be flexible, particularly in the radial direction.

[0260] An embodiment of the invention has proven to be particularly suitable in which the support joint 7a, the transverse joint 7b, the lever joint 12 and / or the actuator joint 11 is designed as a leaf spring joint and / or has at least one leaf spring joint.

[0261] The support joint 7a, the transverse joint 7b, the lever joint 12 and / or the actuator joint 11 can have at least two joint elements 13 arranged axially offset from each other and oriented 90° rotated relative to each other.

[0262] The Fig. Figure 6 shows a schematic view of an exemplary joint or joint assembly of the device 1 with two joint elements 13. The joint can, in particular, be the support joint 7a, the transverse joint 7b, the actuator joint 11, or the lever joint 12. The two joint elements 13 shown are arranged on two separate planes when viewed along an axis of the joint 7a, 7b, 11, 12, with the joint elements 13 being rotated by 90° on adjacent planes or oriented orthogonally to each other. An intermediate element can be arranged between the two joint elements 13, as indicated in the drawing. Similarly, more than two joint elements 13 can be provided. The joint elements 13 are preferably designed as leaf springs.

[0263] The connection of the in the Fig. The joint shown in 6 as an example on components of the device 1 can be arbitrary, preferably as described above for the support joint 7a, the transverse joint 7b, the actuator joint 11 and the lever joint 12.

[0264] Preferably a head joint device 14 is provided, wherein the head joint device 14 is arranged between the holding point 3 and an upper end 6b of the rod leg 6 facing the holding point 3.

[0265] It has proven advantageous if the ankle joint device 7, the support joint 7a, the transverse joint 7b, the lever joint 12, the actuator joint 11 and / or the head joint device 14 has a plurality of joint elements 13, wherein the joint elements 13 are preferably each designed as leaf springs.

[0266] In this regard, reference should be made to the above-described Fig. 6 referred. An analogous setup may also be suitable for the head joint device 14.

[0267] The Fig. Figures 3 to 6 also serve to disclose a principled representation of an embodiment of the holding device 15 according to the invention for holding an optical element 2. The holding device 15 comprises a first device 1a and a second device 1b, each with the features of a device 1 according to the invention. The first device 1a and the second device 1b converge towards a common holding point 3 on the optical element 2. This is shown in the Fig. 3 is illustrated by the dashed lines along the rod legs 6 of the two devices 1a, 1b.

[0268] It should be noted that the first device 1a and the second device 1b each correspond to a device 1 and are, in principle, interchangeable, since the designations "first" and "second" are used primarily for the sake of differentiation. In particular, the first device 1a and the second device 1b can be devices 1 according to the Fig. Represent 3 to 6.

[0269] Preferably, the first device 1a and the second device 1b may form at least an approximately right angle to each other.

[0270] In a preferred embodiment of the holding device 15, an actuating lever 9 of the first device 1a and an actuating lever 9 of the second device 1b are provided. The support joint 7a of the first device 1a, the support joint 7a of the second device 1b, the transverse joint 7b of the first device 1a, the transverse joint 7b of the second device 1b, the actuating lever 9 of the first device 1a, and the actuating lever 9 of the second device 1b are arranged and designed such that the actuating lever 9 of the first device 1a and the second device 1b, respectively, can be tilted relative to a respective rest position of the first device 1a and the second device 1b.This allows deformations of the optical element 2 to be reduced by means of the interaction of the support joints 7a, the transverse joints 7b and the actuating levers 9, in order to counteract a tilting of the holding point 3 relative to the optical element 2 when moving the holding point 3 by actuating one or both actuating levers 9.

[0271] It has proven advantageous if an actuator 10 of the first device 1a is provided for targeted positioning and / or alignment of the optical element 2 and is arranged and designed to move a carrier 4 of the first device 1a. Alternatively or additionally, it may be advantageous if an actuator 10 of the second device 1b is provided for targeted positioning and / or alignment of the optical element 2 and is arranged and designed to move a carrier 4 of the second device 1b.

[0272] Preferably, the actuator 10 of the first device 1a and / or the actuator 10 of the second device 1b is adjustable at least approximately parallel to the respective support joint 7a with respect to a rest position of the device 1a, 1b, wherein the actuator 10 of the respective device 1a, 1b is movably connected to the lower end 6a of the respective rod leg 6 such that by extending or retracting the respective actuator 10, the lower end 6a of the respective rod leg 6 can be displaced at least approximately parallel to the respective transverse joint 7b with respect to the rest position.

[0273] It may be provided that a support foot 5 of the first device 1a is formed integrally with a support foot 5 of the second device 1b.

[0274] It is advantageous if the support joint 7a and / or the transverse joint 7b lies at least in one of the planes spanned by the two devices 1a, 1b, i.e., in the plane of the drawing. Fig. 3 to 5, is bendable or deflectable. Furthermore, it can be advantageous if the support joint 7a and / or the transverse joint 7b is additionally deflectable in a second, orthogonal direction. This can be achieved, for example, by a joint design as described above. Fig. 6 possible.

[0275] The Fig. 4 and Fig. Figure 5 shows the embodiment of the device 1, 1a according to the invention or of the holding device 15 according to the Fig. 3 outside the resting position. The joints, in particular the supporting joint 7a and the transverse joint 7b of the ankle joint assembly 7, are in the Fig. 4 shown during an active deflection by the actuator 10 of the first device 1a. In the Fig. Figure 5 shows the joints, in particular the joints 7a, 7b of the ankle joint device 7, in a passive deflection which may be caused by adjusting the actuator 10 of another device 1 or holding device 15 fixed to the optical element 2.

[0276] In the Fig. 4 and Fig. 5 is the device 1 in the rest position, as shown in Fig. Figure 3 shows the device 1 in the background with thinner lines for better comparison. The thicker lines represent the device 1 in its deflected state. The reference numerals in the drawing also refer to this.

[0277] During active deflection after the Fig. 4. The optical element 2 is moved selectively upwards and to the right by the actuator 10 of the first device 1a retracting. In the illustrated embodiment, the adjustment path of the actuator 10 runs in particular parallel to the support joint 7a of the first device 1a with respect to the rest position, i.e., parallel to the support joint 7a as shown in the background of the Fig. Figure 4 is shown with a thinner line. Due to the active movement of the actuator 10, the actuating lever 9 of the first device 1a, which is movably or articulated to the actuator 10 via the actuator joint 11, assumes a tilted position compared to its rest position. In this position, the support joint 7a, the transverse joint 7b, the actuator joint 1, the lever joint 12, and / or the head joint assembly of the first device 1a may be deflected. This can also apply to the actuating lever 9, as well as the corresponding joints 7a, 7b, 11, 12, and / or the head joint assembly 14 of the second device 1b, whereby the second device 1b is deflected passively.

[0278] The actively induced tilting of the actuating lever 9 of the first device 1a can preferably lead to a transverse movement, in the example shown, in particular a horizontal translational movement, of the lower end 6a of the rod leg 6 of the first device 1a, wherein this movement is transmitted to the lower end 6a of the rod leg 6 via the transverse joint 7b. Furthermore, the support joint 7a is preferably configured and designed to allow the resulting horizontal movement of the lower end 6a of the rod leg 6 of the first device 1a. The rod leg 6 of the first device 1a can experience a movement component in the longitudinal direction of the rod leg 6 and a movement component transverse to it, in particular towards the second device 1b or in a horizontal direction. The longitudinal movement component of the rod leg 6 displaces the holding point 3.In particular, it may be provided that the rod leg 6 of the second device 1b is tilted about the intersection point 8 of the extensions of the axes of the support joint 7a and the transverse joint 7b of the second device 1b, each imagined in the rest position.

[0279] As in the Fig. As can be seen from Figure 4, the head joint devices 14 of the devices 1a, 1b can preferably have an at least approximately opposite bending moment, so that the bending moments at least almost balance each other. In particular, the arrangement of the support joint 7a, the transverse joint 7b and the tiltable actuating lever 9 and their interaction can counteract a tilting of the holding point 3 relative to the optical element 2. The invention thus advantageously avoids the transmission of parasitic forces and / or moments to the optical element 2 and thus its deformation.

[0280] During passive deflection after the Fig. 5 None of the illustrated rod legs 6 are actuated, even though the devices 1a, 1b are not in their rest position. Such a situation can occur if the optical element 2, as described in more detail below, is held by more than one device 1 or more than one holding device 15. With reference to the illustrated embodiment, at least one of the Fig. The optical element 2 is actively deflected by the 5 devices 1 (not shown) or holding devices 15, thereby passively deflecting the devices 1a and 1b shown. It may be desirable, among other things, for the optical element 2 to tilt at the holding point 3 shown. For this purpose, the actuating levers 9 of the passively deflected devices 1a and 1b may be held in place or kept in a positionally stable position. The required mobility can be provided by the ankle joints 7 with their respective support joints 7a and transverse joints 7b of the passively deflected devices 1a and 1b.

[0281] Regarding the Fig. 4 and Fig. Five aspects not described in detail are analogous to the Fig. 3.

[0282] The Fig. Figure 7 shows a schematic representation of an embodiment of the arrangement 16 and the system 17 according to the invention for holding an optical element 2 in a top view. The arrangement 16 comprises at least six devices 1 according to the invention, wherein preferably two devices 1 can form a holding device 15 according to the invention, or the arrangement 16 has three holding devices 15 according to the invention. In particular, each of the holding devices 15 has two devices 1. Instead of the paired arrangement of devices 1 in the form of holding devices 15, the devices 1 could also be arranged individually.

[0283] The one in Fig. The devices 1 or holding devices 15, which are only schematically indicated, can preferably be designed as shown in the Fig. 1 to 6 above.

[0284] Preferably, exactly six devices 1 are provided for the arrangement 16 or the system 17 according to the invention. The devices 1 can be used individually or in pairs, each forming a holding device 15, to hold the optical element 2. Preferably, three holding devices 15 are provided.

[0285] The holding devices 15 are preferably designed as bipods. The two legs of a bipod can each be formed by a device 1 according to the invention.

[0286] Preferably, the devices 1 and / or the holding devices 15 are arranged at least approximately uniformly distributed on an outer edge region of the optical element 2.

[0287] The V-shaped holding devices 15 can preferably be arranged tangentially to the edge of the optical element 2. The holding devices 15 are preferably oriented perpendicular to the optical element 2 or to an optical surface 2a of the optical element 2. However, the holding devices 15 can also be arranged and / or oriented differently.

[0288] In a preferred embodiment of the invention, the holding devices 15 are also provided to position and / or align the optical element 2.

[0289] If one of the devices 1 or holding devices 15 arranged on the optical element 2 is actively deflected for positioning and / or aligning the optical element 2, in particular by an actuator 10, a passive deflection can occur in the adjacent devices 1 or holding devices 15. This is primarily due to the fact that forces and / or moments introduced into the optical element 2 at the holding point 3 of the actively deflected device or holding device 15 can be transmitted via the optical element 2 to the holding point 3 of the adjacent devices 1 or holding devices 15. For a comparison of active and passive deflection, reference should also be made to the preceding description of the Fig. 4 and Fig. 5 referred.

[0290] When the illustrated embodiment of the arrangement 16 is considered together with the optical element 2, a system 17 according to the invention is obtained. The system 17 thus comprises the optical element 2, at least six devices 1 according to the invention, wherein two devices 1 can each form a holding device 15 according to the invention, or comprises three holding devices 15 according to the invention for holding the optical element 2. The optical element 2 can in particular be a mirror or a lens.

[0291] Not shown in the exemplary embodiment, but fundamentally possible, is that three devices 1 according to the invention are combined to form a common assembly, converging at a common holding point 3, with the rod legs 6 of the devices 1 also converging. Preferably, two such assemblies are provided to hold an optical element 2.

[0292] The Fig. References 3 to 7 also serve to disclose a method according to the invention for holding and in particular for positioning and / or aligning an optical element 2, wherein the optical element 2 is held and in particular positioned and / or aligned with at least one device 1 according to the invention and / or a holding device 15 according to the invention or an arrangement 16 according to the invention.

[0293] The exemplary implementations according to the Fig. 3 to 7 of the device 1 according to the invention, or of the holding device 15 according to the invention, or of the arrangement 16 according to the invention, or of the system 17 according to the invention, or of the method according to the invention, are particularly suitable for holding, and optionally for positioning and / or aligning, an optical element 2 of a mask inspection system or a lithography system.

[0294] In a mask inspection system according to the invention for inspecting a photomask, comprising an illumination device with a radiation source and optics, which have at least one optical element 2, and a detection device, the optical element 2 is held, and optionally positioned and / or aligned, by at least one device 1 and / or a holding device 15 or an arrangement 16 according to the invention. The photomask can, in particular, be a reticle 106, 203 for a projection exposure system 100, 200 according to the Fig. 1 and Fig. 2 trade.

[0295] The optical element 2 of a lithography system can in particular be an optical element 116, 118, 119, 120, 121, 122, Mi, 207 of a projection exposure system 100, 200 for semiconductor lithography, with an illumination system 101, 201 with a radiation source 102 and optics 103, 109, 206, according to the Fig. 1 and Fig. 2. In a lithography system according to the invention, at least one of the optical elements 116, 118, 119, 120, 121, 122, Mi, 207 is held by at least one device 1 according to the invention and / or a holding device 15 according to the invention or an arrangement 16 according to the invention, and optionally positioned and / or aligned. Reference symbol list 1 Device 1a First device 1b Second device 2 Optical element 2a Optical surface 3 stopping point 4 carriers 5 support foot 6 Stem leg 6a Lower end (of the rod leg 6) 6b Upper end (of the rod leg 6) 7 Ankle device 7a Support joint 7b Transverse joint 8 Virtual Intersection 9 adjusting levers 10 Actuator 11 Actuator joint 12 Lever joint 13 Joint element 14 Head joint device 15 Holding device 16 Arrangement 17 System 100 EUV projection system 101 Lighting system 102 Radiation source 103 Lighting optics 104 object field 105 Object level 106 reticles 107 label holders 108 Reticle displacement drive 109 Projection optics 110 image field 111 Image plane 112 wafers 113 wafer holders 114 Wafer transfer drive 115 EUV / Useful / Illumination radiation 116 Collector 117 Intermediate focus plane 118 Deflection mirrors 119 first faceted mirror / field faceted mirror 120 first facets / field facets 121 Second faceted mirror / Pupil faceted mirror 122 second facets / pupil facets 200 DUV projection exposure system 201 Lighting system 202 reticulation days 203 reticles 204 wafers 205 wafer holders 206 Projection optics 207 lens Version 208 209 lens bodies 210 projection beam Mi Mirror QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2018 200 178 A1 [0014, 0015] DE 10 2012 213 794 A1

[0173] DE 10 2008 009 600 A1 [0203, 0207] US 2006 / 0132747 A1

[0205] EP 1 614 008 B1

[0205] US 6,573,978

[0205] US 2018 / 0074303 A1

[0220]

Claims

[1] Device (1) for holding an optical element (2), in particular an optical element of a mask inspection system or a lithography system, comprising a holding point (3) for connection with the optical element (2), a support (4) and a support base (5), wherein the holding point (3) is connected to the support (4), wherein the support (4) has at least one rod leg (6) and an ankle joint (7), and wherein the ankle joint (7) pivotally connects a lower end (6a) of the rod leg (6) facing away from the holding point (3) to the support base (5), characterized by , that the ankle joint device (7) has a support joint (7a) and a transverse joint (7b), wherein the support joint (7a) connects the lower end (6a) of the rod leg (6) directly to the support foot (5) in a pivotal manner. [2] Device (1) according to claim 1, characterized by, that the support joint (7a) and the transverse joint (7b) are aligned at least approximately at a right angle to each other in a rest position of the device (1). [3] Device (1) according to claim 1 or 2, characterized by , that the rod leg (6) can be tilted about a virtual intersection point (8) of extensions of an axis of the support joint (7a) and an axis of the transverse joint (7b) imagined in a rest position of the device (1). [4] Device (1) according to claim 1, 2 or 3, characterized by , that an adjusting lever (9) is provided, wherein the lower end (6a) of the rod leg (6) is operatively connected to the support foot (5) via the adjusting lever (9), and wherein the transverse joint (7b) pivotally connects the lower end (6a) of the rod leg (6) to the adjusting lever (9). [5] Device (1) according to claim 4, characterized by, that the support joint (7a), the transverse joint (7b) and the actuating lever (9) are arranged and designed such that the actuating lever (9) can be tilted relative to a rest position of the device (1) in order to reduce deformations of the optical element (2) when moving the holding point (3) by actuating the actuating lever (9) by means of the interaction of the support joint (7a), the transverse joint (7b) and the actuating lever (9) in order to counteract a tilting of the holding point (3) relative to the optical element (2). [6] Device (1) according to any one of claims 1 to 5, characterized by that the carrier (4) is movable by means of an actuator (10), preferably fixed to the carrier base (5), for targeted positioning and / or alignment of the optical element (2). [7] Device (1) according to claim 6, characterized by , that an actuator joint (11) is provided to connect the actuating lever (9) to the actuator (10) in a pivotal manner. [8] Device (1) according to claim 6 or 7, characterized by , that the actuator (10) is adjustable at least approximately parallel to the support joint (7a) with respect to a rest position of the device (1), wherein the actuator (10) is movably connected to the lower end (6a) of the rod leg (6) via the adjusting lever (9) such that by extending or retracting the actuator (10) the lower end (6a) of the rod leg (6) can be displaced at least approximately parallel to the transverse joint (7b) with respect to the rest position. [9] Device (1) according to any one of claims 4 to 8, characterized by , that a lever joint (12) is provided to connect the actuating lever (9) pivotally to the support foot (5). [10] Device (1) according to any one of claims 6 to 9, characterized by, that the actuating lever (9) is at least partially arranged between the ankle joint assembly (7) and the actuator (10), wherein the actuating lever (9) is pivotally connected to the lower end (6a) of the rod leg (6) via the transverse joint (7b), to the support foot (5) via the lever joint (12) and / or to the actuator (10) via the actuator joint (11). [11] Device according to any one of claims 1 to 10, characterized by , that the rod legs (6) are rigid, especially in the axial direction. [12] Device according to any one of claims 1 to 11, characterized by , that the rod legs (6), especially in the radial direction, are flexible. [13] Device (1) according to any one of claims 1 to 12, characterized by , that the support joint (7a), the transverse joint (7b), the lever joint (12) and / or the actuator joint (11) is designed as a leaf spring joint and / or has at least one leaf spring joint. [14] Device (1) according to any one of claims 1 to 13, characterized by, that the support joint (7a), the transverse joint (7b), the lever joint (12) and / or the actuator joint (11) has at least two joint elements (13) arranged axially offset from each other and oriented 90° rotated relative to each other. [15] Device (1) according to any one of claims 1 to 14, characterized by , that a head joint device (14) is provided, wherein the head joint device (14) is arranged between the holding point (3) and an upper end (6b) of the rod leg (6) facing the holding point (3). [16] Device (1) according to any one of claims 1 to 15, characterized by , that the ankle joint assembly (7), the support joint (7a), the transverse joint (7b), the lever joint (12), the actuator joint (11) and / or the head joint assembly (14) has a plurality of joint elements (13), wherein the joint elements (13) are preferably each designed as leaf springs. [17] Holding device (15) for holding an optical element (2), in particular an optical element of a mask inspection system or a lithography system, at least comprising a first device (1a) and a second device (1b) each according to one of claims 1 to 16, characterized by , that the first device (1a) and the second device (1b) converge towards a common stopping point (3) on the optical element (2). [18] Holding device (15) according to claim 17, characterized by that the first device (1a) and the second device (1b) form at least an approximate right angle to each other. [19] Holding device (15) according to claim 17 or 18, characterized by, that an actuating lever (9) of the first device (1a) and an actuating lever (9) of the second device (1b) are provided, wherein the support joint (7a) of the first device (1a), the support joint (7a) of the second device (1b), the transverse joint (7b) of the first device (1a), the transverse joint (7b) of the second device (1b), the actuating lever (9) of the first device (1a) and the actuating lever (9) of the second device (1b) are arranged and designed such that the actuating lever (9) of the first device (1a) or of the second device (1b) is tiltable relative to a respective rest position of the first device (1a) or of the second device (1b) in order to reduce deformations of the optical element (2) by means of the interaction of the support joints (7a), the transverse joints (7b) and the actuating levers (9), in order to prevent tilting of the holding point (3) when moving the holding point (3) by actuating one or both actuating levers (9). to counteract relative to the optical element (2). [20] Holding device (15) according to claim 17, 18 or 19, characterized by , that an actuator (10) of the first device (1a) is arranged and designed for targeted positioning and / or alignment of the optical element (2) in such a way as to move a carrier (4) of the first device (1a), and / or an actuator (10) of the second device (1b) is arranged and designed for targeted positioning and / or alignment of the optical element (2) in such a way as to move a carrier (4) of the second device (1b). [21] Holding device (15) according to claim 20, characterized by, that the actuator (10) of the first device (1a) and / or the actuator (10) of the second device (1b) is adjustable at least approximately parallel to the respective support joint (7a) with respect to a rest position of the device (1a, 1b), wherein the actuator (10) of the respective device (1a, 1b) is movably connected to the lower end (6a) of the respective rod leg (6) such that by extending or retracting the respective actuator (10) the lower end (6a) of the respective rod leg (6) can be displaced at least approximately parallel to the respective transverse joint (7b) with respect to the rest position. [22] Holding device (15) according to one of claims 17 to 21, characterized by , that a support foot (5) of the first device (1a) is formed integrally with a support foot (5) of the second device (1b). [23] Arrangement (16) for holding an optical element (2), in particular an optical element of a mask inspection system or a lithography system, comprising at least six devices (1) according to any one of claims 1 to 16 or three holding devices (15) according to any one of claims 17 to 22. [24] Arrangement (16) according to claim 23, characterized by that the devices (1) and / or the holding devices (15) are arranged at least approximately uniformly distributed on an outer edge region of the optical element (2). [25] System (17) comprising an optical element (2), in particular an optical element of a mask inspection system or a lithography system, and comprising at least six devices (1) according to any one of claims 1 to 16 or three holding devices (15) according to any one of claims 17 to 22 for holding the optical element (2). [26] System (17) according to claim 25, characterized by, that the optical element (2) is a mirror or a lens. [27] Method for holding and in particular for positioning and / or aligning an optical element (2), in particular an optical element of a mask inspection system or a lithography system, characterized by , that the optical element (2) is held and in particular positioned and / or aligned by at least one device (1) according to one of claims 1 to 16 and / or a holding device (15) according to one of claims 17 to 22 or an arrangement (16) according to claim 23 or 24. [28] Mask inspection system for inspecting a photomask, in particular a reticule (106, 203) for a projection exposure system (100, 200), comprising an illumination device with a radiation source and optics comprising at least one optical element (2), and a detection device, characterized by, that the optical element (2) is held by at least one device (1) according to one of claims 1 to 16 and / or a holding device (15) according to one of claims 17 to 22 or an arrangement (16) according to claim 23 or 24. [29] Lithography system, in particular projection exposure system (100, 200) for semiconductor lithography, with an illumination system (101, 201) with a radiation source (102) and optics (103, 109, 206) which includes at least one optical element (116, 118, 119, 120, 121, 122, Mi, 207), characterized by , that the optical element (116, 118, 119, 120, 121, 122, Mi, 207) is held by at least one device (1) according to one of claims 1 to 16 and / or a holding device (15) according to one of claims 17 to 22 or an arrangement (16) according to claim 23 or 24.

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