Optical device and method for controlling an optical device

Abstract

The invention relates to an optical device (1) having a number of optically active surfaces (2), each of which can be tilted by a respective autonomously controllable manipulation device (3) associated with the surface (2). According to the invention, the manipulation devices (3) are designed to position and / or curve the surfaces (2), and an overall control device (4) is provided which controls the manipulation devices (3) such that at least two of the surfaces (2) interact in a planned and coordinated manner to form an overall surface (5).

Description

Technical Field

[0001] This application claims the priority of German Patent Application No. 10 2021 200 113.0, the content of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to an optical device having a plurality of optically active surfaces, the surfaces being tiltable respectively by separate autonomously controllable actuators assigned to the surfaces.

[0003] The present invention further relates to a method for controlling an optical device having a plurality of optically active surfaces that are autonomously controllable to tilt respectively.

Background Art

[0004] As is known, optical elements affect the properties of light rays interacting with the optical elements. In particular, the surfaces of optical elements contribute significantly to this effect since, for example, reflection and / or refraction occur there. For example, examples of optical elements to be mentioned include plane mirrors, concave mirrors, convex mirrors, faceted mirrors, convex lens elements, concave lens elements, concave-convex lens elements, plano-convex lens elements, and plano-concave lens elements. In this case, as a result of the surfaces of concave mirrors and convex mirrors having a radius of curvature, for example, a focal point can be formed.

[0005] In a faceted mirror, a plurality of segment-shaped plane and / or curved individual mirrors are combined. In this case, as a result of the segment-shaped individual mirrors being tiltable, each can reflect the light incident on the faceted mirror in a different way.

[0006] Projection exposure apparatuses have a large number of optical elements. In particular, when using optical elements in micro-lithography DUV (deep ultraviolet) projection exposure apparatuses, and especially when using optical elements in micro-lithography EUV (extreme ultraviolet) projection exposure apparatuses, the dynamic adaptability of the optical elements for implementing different illumination modes, for example, is particularly important.

[0007] In the illumination system of an EUV lithography apparatus, the field facets of the field facet mirror are assigned to pupil facets at different positions. Due to different angular arrangements and different distances, an optimal spot size cannot be set here. All known technical solutions deviate somewhat from the ideal, and disturbance effects such as thermal effects also limit the setting. This leads to a loss of transmittance and poor imaging characteristics of the known system.

[0008] Patent Document 1 discloses a displacement device that pivots a mirror element with two pivoting degrees of freedom, and has an electrode structure having actuator electrodes designed as comb electrodes. In this case, all the actuator electrodes are arranged in a single plane, and the actuator electrodes form a direct drive for pivoting the mirror element.

[0009] An optical element equipped with an imaging error and a position correction device is known from Patent Document 2.

[0010] The drawback of a macroscopic facet mirror known from the prior art in which the radius of curvature of the facet is fixed, particularly a field facet mirror, is that when the segmental individual mirrors are tilted dynamically, the curvature of the individual mirrors is optimized for another target segment, so that, for example, the position of the focus does not coincide with the new target segment.

[0011] Furthermore, it is impossible to form a focus formed by the interaction of a plurality of individual mirrors by tilting the individual mirrors.

[0012] The drawback of the optical elements known from the prior art of a projection exposure apparatus is that the focus characteristics cannot be dynamically adapted during the operation of the projection exposure apparatus.

[0013] A displacement device that pivots a mirror element formed at least partially by so-called MEMS technology (microelectromechanical system technology) is known from Patent Document 1.

[0014] Another disadvantage of optical elements known from the prior art is that the optical element is composed of a plurality of components, which may increase the risk of malfunction and / or failure.

Prior Art Documents

Patent Documents

[0015]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0016] The present invention is based on the object of avoiding the disadvantages of the prior art and in particular of creating an optical device that enables an improvement in the setting.

[0017] According to the present invention, this object is achieved by a device having the features described in claim 1.

[0018] According to the present invention, this object is also achieved by a device having the features described in claim 2.

[0019] The present invention further aims to avoid the disadvantages of the prior art and in particular to create a method for controlling an optical device that enables an improvement in the setting.

[0020] According to the present invention, this object is achieved by a method having the features described in claim 13.

[0021] The present invention is based on the object of avoiding the disadvantages of the prior art and in particular of creating a computer program product that enables an improvement in the setting.

[0022] The present invention is based on the object of avoiding the disadvantages of the prior art and in particular of producing an optical element, in particular a lithography system having at least one field facet mirror, which enables an improvement in imaging.

Means for Solving the Problems

[0023] The optical device according to the invention as claimed in claim 1 has a plurality of optically active surfaces, which can each be tilted by means of separate autonomously controllable actuators assigned to the surface. According to the invention, the actuators are configured to position and curve the surfaces, and there is provided an overall control device which controls the actuators such that at least two of the surfaces interact in a planned and coordinated manner to form the overall surface.

[0024] The optical device according to the invention as claimed in claim 2 has a plurality of optically active surfaces, which can each be tilted by means of separate autonomously controllable actuators assigned to the surface. According to the invention, the actuators are configured to position and / or curve the surfaces, and there is provided an overall control device which controls the actuators such that at least two of the surfaces interact in a planned and coordinated manner to form the overall surface, and each surface has its own control device configured to control the tilt as well as the curvature and / or the positioning of the respective surface, and the overall control device controls all the surfaces such that the gaps between adjacent surfaces which are tilted relative to one another of the overall surface are reduced, preferably minimized, while maintaining the defined tilt of the individual surfaces, and positions and / or curves the overall surface.

[0025] Advantageous features and configurations of two devices according to the invention are described below.

[0026] By combining the tilt degrees of freedom with at least one of the two curvature and / or positioning degrees of freedom, the overall surface formed by the individual surfaces can be shaped substantially freely. This has the advantage that the individual optical devices can exert a number of different shaping and light guiding effects on the wavefront incident on the optical device.

[0027] A planned and coordinated interaction can be understood to particularly mean a mutually adapted interaction of surfaces.

[0028] Furthermore, the overall surface can be formed by at least one group, preferably the majority, in particular more than 90 percent of the surfaces.

[0029] The setting of the optical element is significantly improved by additional degrees of freedom such as the movement of the surface in a direction perpendicular to the surface and / or the change in the radius of curvature of the surface.

[0030] Thereby, it is also possible to compensate for disturbing effects such as the curvature of the surface due to thermal influences. Optical devices known from the prior art are suitable for tilting the surface as desired and, in some cases, for adjusting the height, i.e., the adjustment perpendicular to the surface of the mirror, or for compensating for surface deformations, but in known optical devices, a planned and coordinated control of the surfaces such that the overall surface, i.e., the overall surface of any shape within the system limits, can be set is not disclosed.

[0031] It is particularly advantageous if the individual surfaces are controllable such that the inclination of each surface, the height adjustment of the surface, and the curvature or deformation of the surface can preferably be carried out or set simultaneously.

[0032] Within the scope of the present invention, the surface can in particular be a surface segment.

[0033] Therefore, the device according to the present invention enables a more accurate reproduction of any optical surface area compared to the prior art.

[0034] In an advantageous development of the optical device according to the present invention, the overall control device can be configured to control the operating device such that the gap between adjacent surfaces inclined relative to each other is reduced by the positioning and / or curvature of the surface.

[0035] Thus, by combining the inclination of the individual surfaces with their translational positioning and / or their curvature, the device according to the invention enables the surface areas formed by the surfaces to be formed while suppressing the generation of gaps between the individual surfaces.

[0036] Within the scope of the present invention, it can also be understood that the offset between the individual surfaces is a gap formed in the direction of the surface normal rather than in the plane of the surface.

[0037] The surface area designed in this way has the advantage that the disturbance of the radiation shaping function of the surface area due to the gaps between the surfaces is reduced.

[0038] It has been found that within the scope of the present invention, by combining the inclination of the surfaces with the positioning of the surfaces and / or the curvature of the surfaces, the gaps can be sufficiently avoided.

[0039] It can be understood that adjacent surfaces are inclined with respect to each other when at least one of the surfaces is inclined from its initial direction.

[0040] In an advantageous development of the optical device according to the invention, the overall control device can control the operating device such that the gap between adjacent surfaces inclined with respect to each other is minimized by the positioning and / or curvature of the surfaces.

[0041] The minimization of the gap beyond just the reduction of the gap enables, as a result, the minimization of the disturbance of the radiation shaping function of the surface.

[0042] In an advantageous development of the optical device according to the invention, the operating device can have an inclination device for inclining the surface with respect to the initial direction of the average surface normal of the surface, and the operating device can have a curvature device for curving the surface and / or a positioning device for moving the surface parallel to the plane with respect to the initial position.

[0043] Another development in which the inclination device and the curvature device and / or the positioning device are designed as separate devices can also be advantageous.

[0044] A combination of the two above-described development forms can be particularly advantageous, in which case the operating device can have an inclination device for inclining the surface with respect to the initial direction of the average surface normal, and the operating device can have a curvature device for curving the surface and / or a positioning device for moving the surface up and down parallel to the plane with respect to the initial position, and the inclination device as well as the curvature device and / or the positioning device are designed as separate devices.

[0045] If the operating device has the inclination device as well as the curvature device and / or the positioning device in a design consisting of at least two parts, the advantage is obtained that the functional elements are clearly separated, whereby for example a failure of an individual functional element, for example the inclination device, does not lead to a failure of the remaining functional element(s), so that errors are less likely to occur in the operating device.

[0046] It is particularly advantageous if the operating device has an inclination device, a curvature device, and a positioning device, each designed as a separate device.

[0047] In this case, the inclination device preferably inclines the surface individually about two axes, so that two degrees of freedom φ x and φ y are obtained.

[0048] Furthermore, from the effect of the positioning device that moves the surface up and down parallel to the plane with respect to the initial position, a further degree of freedom in the z direction is obtained.

[0049] The curvature device preferably forms at least two radii of curvature R x and R y to provide a further degree of freedom for shaping the surface.

[0050] The above degrees of freedom φ x and φ y , z, R x , R y are here available for shaping each surface, enabling a particularly efficient shaping of the overall surface consisting of the surfaces, which particularly efficiently minimizes the formation of gaps.

[0051] It is advantageous if the operating device has an inclination control device for controlling the inclination device, and a positioning control device for controlling the positioning device and / or a curvature control device for controlling the curvature device.

[0052] As long as the inclination device, the positioning device, and the curvature device can be controlled by respective appropriate control devices, it is preferable that each of the above degrees of freedom of the surface shaping can be set and controlled in an open-loop control, particularly in a closed-loop control.

[0053] Particularly to enable closed-loop control, the inclination control device and / or the positioning control device and / or the curvature control device may have a sensor configured to obtain an inclination and / or a curvature and / or a positioning.

[0054] In particular, the curvature control device and / or the overall control device may have a piezoresistive sensor to measure the current mirror curvature and thus form a closed-loop control system.

[0055] Thereby, for example, compensation for thermal effects can be enabled.

[0056] It is advantageous if the inclination control device, the positioning control device, and the curvature control device are designed separately and / or as part of an overall control device.

[0057] Furthermore, for example, only some of the surfaces may be individually controllable, while the corresponding inclination control device, positioning control device, and curvature control device being part of the overall control device enables the control of the remaining ones respectively.

[0058] It is particularly advantageous if the overall control device and / or each of the inclination control device, the positioning control device, and the curvature control device has at least one closed-loop control device for controlling the generation of the above degrees of freedom φ x 、φ y 、z、R x 、R y 。

[0059] It is advantageous if the overall control device is configured to approximate a desired shape of the overall surface by controlling the tilting device and / or the bending device and / or the positioning device.

[0060] It is particularly advantageous if the overall control device controls the tilting device and / or the bending device and / or the positioning device such that the overall surface composed of the individual surfaces at least substantially corresponds to the desired overall shape.

[0061] For this purpose, it is particularly advantageous if the overall control device is configured to execute a computer program product that simulates such an approximation and / or performs it by means of mathematical modeling.

[0062] Furthermore, it may be advantageous if a sensor device is provided to measure the wavefront emerging from the overall surface, thus to identify and evaluate the interaction of the surfaces, and, if necessary, to adjust or readjust the orientation of the surface preferably iteratively using the overall control device.

[0063] For example, as part of the overall control device, it is advantageous if a feedback device is provided that approximates the actual state of the wavefront emerging from the overall surface determined by the sensor device to a target state by causing or adjusting the tilt and / or the positioning and / or the curvature of the surface.

[0064] It is advantageous if the surfaces are at least substantially seamlessly adjacent to each other.

[0065] If the surfaces are at least seamlessly connected, the occurrence of gaps is at least substantially completely eliminated.

[0066] As a result, the overall surface can perform the desired beam shaping function at least substantially without limitation.

[0067] It is further advantageous if the overall surface is designed to have a single focus or a plurality of discrete foci.

[0068] In a favorable interaction, the individual surfaces can form, for example, a concave mirror having a single focus.

[0069] For example, for illuminating different spatially separated target structures, it can be particularly advantageous if the overall surface has a plurality of discrete foci.

[0070] It is advantageous that such a desired shape of the overall surface can be accurately and reliably approximated using the optical device according to the invention.

[0071] It is advantageous if the surface is designed to reflect light, in particular EUV light.

[0072] When the surface is designed to be light-reflective, in particular EUV light-reflective, the optical device can be used, for example, as a deformable mirror, in particular as a field facet mirror of an EUV projection exposure apparatus.

[0073] It is advantageous if at least some of the surfaces have a reflective layer system formed on at least a part of each surface.

[0074] Since the reflective layer system has a reliably high reflectivity in the EUV wavelength range, a reflective layer system formed at least partially on the surface can be advantageous, in particular for increasing the reflectivity of each surface in the wavelength range of EUV light.

[0075] It is advantageous if the bending device is set so that the surface forms a curvature of less than 20 1 / m, preferably 0.2 1 / m to 20 1 / m, preferably 0.5 1 / m to 4 1 / m, in particular 1 1 / m to 2 1 / m.

[0076] Radius of curvature R x and R y Restricting the generation of degrees of freedom of results in the advantage that damage to the reflective layer system can be avoided as a result of the mechanical load on the surface, in particular the reflective layer system that can be formed on the surface, being restricted.

[0077] As a result, it is advantageous that the service life of each surface, and thus of the entire optical device, can be extended.

[0078] Within the scope of the present invention, it has been found advantageous to limit the curvature to less than 20 1 / m, preferably less than 10 1 / m, and particularly less than 2 1 / m.

[0079] Furthermore, it has been found advantageous if the bending device is configured to form a curvature of 0.2 1 / m or more on the surface. Advantageously, the bending device should be configured to achieve a surface curvature that results in an advantageous reduction of the gap between the individual surfaces.

[0080] It is advantageous if the bending device is configured to form at least two curvatures on the surface.

[0081] In principle, two principal curvatures are sufficient to achieve any desired curvature shape of the surface. Therefore, the formation of two curvatures, particularly two curvatures whose curvature curves extend perpendicular to each other, is particularly advantageous.

[0082] However, it may be advantageous if the bending device is configured to form three or more curvatures on the surface, for example, to set the desired curvature or shape of the surface even more precisely and accurately.

[0083] A development of the present invention may also lie in arranging at least one reinforcing element on the surface, which preferably improves the curvature of the surface by reinforcing a specific region of the surface and thus acting, for example, as a fixing point for the curved surface.

[0084] Furthermore, the operating device may have a plurality of, preferably each separate, bending device and / or tilting device and / or positioning device.

[0085] For example, two bending devices may be arranged one above the other to bend the surface in different directions.

[0086] It is advantageous if the surface and / or the operating device are arranged on a common body.

[0087] When the surfaces are arranged on a common body, this provides a stable common base for each surface and the associated operating devices. Thus, it is advantageous that the common body can minimize thermally and / or mechanically induced drifts of the individual surfaces and the operating devices associated with the surfaces relative to each other.

[0088] Furthermore, it is advantageous if a tilting device and / or a bending device and / or a positioning device is arranged between the body and each surface.

[0089] When elements of the operating devices, namely a tilting device and / or a bending device and / or a positioning device, are arranged between the body and each surface, this has the mechanical effect that each device has the body as a contact part and a stable base, and in particular the advantage that the optical properties of the surface are neither impaired nor worsened by devices arranged near or on the surface.

[0090] It is advantageous if a tilting device and / or a bending device and / or a positioning device assigned to one of the surfaces is functionally and / or physically connected to the body and each surface, and preferably also to each other.

[0091] When the individual devices of the operating devices, namely the tilting device, the bending device, and the positioning device, are functionally and / or spatially connected to the body and each surface, this has the advantage of ensuring the force transmission that may be necessary for the deformation of the surface by the individual devices.

[0092] For the tilting and / or deformation and / or positioning of the surface, one device can act on the other devices. For example, the positioning device can move both the tilting device and the bending device and further move the surface. For this purpose, it is particularly advantageous if the individual devices are physically connected to each other so that such positioning can be reliably performed.

[0093] Furthermore, when the devices are functionally and / or physically connected to each other, such effects of the devices on each other can also be reliably achieved.

[0094] Particularly advantageous is an integrated configuration of the operating device such that the tilting device and / or the bending device and / or the positioning device are connected to each other and integrally to the body and each surface.

[0095] With the integrated configuration, the desired functional and / or physical connections can be achieved particularly reliably, even in a particularly compact form.

[0096] It is advantageous if the tilting device and / or the bending device and / or the positioning device are designed using MEMS technology (microelectromechanical systems technology).

[0097] By designing the tilting device and / or the bending device and / or the positioning device using microelectromechanical systems technology or MEMS technology, the advantage is obtained that the devices are designed on a very small scale, in which case the devices can be controlled by electrical signals and the mechanical changes of the devices, in particular the mechanical effects, can be triggered or achieved by signals.

[0098] By using electrical signals, the control can be carried out advantageously, efficiently and in particular in a miniaturized manner.

[0099] The formation of the tilting device and / or the bending device and / or the positioning device using a coating method is particularly advantageous individually.

[0100] It is advantageous if the positioning device is formed by a deflectable membrane on the cavity, preferably electrostatically actuable.

[0101] Since the positioning device is formed by a deflectable membrane on the cavity, which is preferably electrostatically actuable, it is advantageous that the device arranged on the membrane can be easily shifted along the normal to the surface of the membrane that deflects it. It is particularly advantageous that such a positioning device is somewhat technically similar to what is known as a MEMS microphone, and as a result it is particularly advantageous that such a conversion can be carried out simply and reliably.

[0102] Here, it may be advantageous if the membrane is integrally connected to an element of a positioning device that holds and / or is connected to the membrane.

[0103] Furthermore, it may be advantageous if the bending device is formed by at least one stretchable and / or contractible actuator element, preferably a piezo element.

[0104] For the realization of the bending device by arranging at least one stretchable and / or contractible actuator element, preferably a piezo element, in an arrangement that is interlocked with the surface, there is the advantage that the curvature of the surface can be induced by the extension and / or contraction of at least one actuator element.

[0105] The use of a piezo element as an actuator element has the advantage that it can be designed in a small form and can be controlled particularly by an electrical signal.

[0106] The advantage of electrically controlling the bending device has already been explained in relation to MEMS technology.

[0107] It is advantageous if the bending device is formed by at least two, preferably at least four, actuator elements arranged along at least two axes.

[0108] With at least two, preferably at least four, actuator elements, at least two principal curvatures can be induced on the surface. Thus, according to Euler's theorem, any curvature is formed as a linear combination of the principal curvatures induced by the actuator elements arranged along at least two axes, so that at least substantially any curvature of the surface can be realized.

[0109] It may be advantageous if the bending device is arranged between the surface and the tilting device.

[0110] The arrangement of the bending device between the surface and the tilting device has the advantage that the bending device can bend or affect the surface without the need to also bend the tilting device by the bending device.

[0111] As a result, the bending device can advantageously be of a simple design and can in particular be designed such that the expected load is reduced.

[0112] It is advantageous if the positioning device is arranged between the tilting device and the body.

[0113] If the positioning device is arranged advancing from the surface and below the tilting device, the tilting device does not need to tilt the positioning device in addition to the bending device that can be arranged below the surface. Since the positioning device has only one degree of freedom, it can be designed with the lowest complexity and thus with a high expected load.

[0114] Thus, it is particularly advantageous if the positioning device is arranged on the body, for example on a common body of the surface, the tilting device is arranged above the positioning device, the bending device above that, and the surface above that.

[0115] In an advantageous development of the device according to the invention, the bending device can be configured to correct unwanted deformations of the surface assigned to it.

[0116] Such correction can be particularly advantageous when using the surface, if only a very small part of the surface needs to be bent for the correction of unwanted deformations. In this case, only a part of the bending device can be brought into an operating state.

[0117] This has, for example, the advantage that less heat is introduced into the optical device for this purpose, since only a part of the bending device is in operation.

[0118] For this purpose, it can be advantageous if a plurality of, preferably 11 or more, actuator elements are arranged on the surface body.

[0119] In this way, even if the undesirable deformation of the surface is small, it can be corrected.

[0120] It is advantageous if the surface is formed on a surface body having a thickness of 1 μm to 500 μm.

[0121] The surface as a very thin possible region arranged on a mathematical and thus abstract surface can advantageously be arranged on a surface body that gives stability to the surface. For this purpose, the surface body can advantageously have a thickness of 1 μm to 500 μm, and within the scope of the present invention, it has been found that this is an appropriate compromise between the mechanical stability of the surface body and, for example, low weight.

[0122] It is advantageous if the actuator element is arranged in direct contact with the surface body.

[0123] When the actuator element is in direct contact with the surface body, the actuator element can shape the surface body and, accordingly, the surface arranged on the surface body in a particularly simple manner. For example, by contracting two actuator elements arranged spaced apart from each other along one axis in any case to contract and deform a region of the surface body, curvature of the surface body is brought about along the axis on which the actuator element is arranged.

[0124] It is advantageous if the actuator elements are arranged spaced apart from the surface body on the side of the surface body opposite to the surface.

[0125] When the actuator elements are arranged so as to be spaced apart from the surface body, for example, when the surface body curves, the surface body may reach a cavity arranged between the actuator element and the surface body, so that the surface can be easily curved.

[0126] In particular, such an embodiment enhances the lifting effect of the actuator element that may occur when the actuator element acts on the surface body and thus on the surface.

[0127] It is preferably arranged on the outer periphery of the surface body, and it is preferable to provide at least one mounting element configured to transmit the force applied by one or more actuator elements to the surface body.

[0128] When the bending device is implemented by layer formation, it may be advantageous if the actuator elements are arranged and / or formed in a layer spaced apart from the surface body.

[0129] It is advantageous if the surface is hexagonal or triangular or rectangular, preferably square.

[0130] In order to achieve an overall surface with the smallest possible gap, it has been found that it is advantageous if the surface is hexagonal or triangular or rectangular, but preferably square.

[0131] In the case of a hexagonal surface, for example, it may be advantageous if six actuator elements are symmetrically arranged under the surface.

[0132] This type of geometric shape makes it possible to form or mosaic the entire surface without generating defects. Defects occur, for example, in the case of a round surface that cannot form the entire surface by joining at least substantially seamlessly.

[0133] The area of the surface is 0.5 mm 2 ~10 mm 2 Preferably 0.9 mm 2 ~2 mm 2 Particularly preferably 1 mm 2 It is advantageous if it is.

[0134] The area of the above surface is known to be particularly suitable for the formation of a normal overall surface, for example, a facet mirror of an EUV projection exposure apparatus.

[0135] In an advantageous development of the device according to the invention, each surface can have its own control device configured to control the inclination and curvature and / or positioning of the respective surface, and to position and / or curve all the surfaces as a whole such that, while maintaining the defined inclination of the individual surfaces, the gap between adjacent surfaces inclined with respect to one another of the overall surface is reduced, preferably minimized.

[0136] In particular, the inclination and / or curvature and / or positioning can be carried out iteratively one after the other and, in some cases, the overall surface can be controlled a plurality of times by the overall control device such that the overall surface gradually assumes the desired shape by the overall control device.

[0137] The invention further relates to a method for controlling an optical device having a plurality of optically active surfaces.

[0138] In the method according to the invention for controlling an optical device having a plurality of optically active surfaces that can be autonomously controlled to incline respectively, the surfaces are inclined and / or positioned and / or curved such that at least two of the surfaces interact in a planned and coordinated manner to generate the overall surface.

[0139] By achieving the overall surface in this way, the incident wavelength can be affected in a planned and coordinated manner over a wide range.

[0140] In the method according to the invention, the degrees of freedom of inclination of the surfaces can be used to form the overall surface. In addition to the degrees of freedom of inclination, the degrees of freedom of curvature of the surfaces and / or the degrees of freedom of positioning of the surfaces can also be used.

[0141] It should be noted here that each degree of freedom may not be used. However, in the method according to the invention, they must be available in at least one of the three combinations of inclination + curvature and / or inclination + positioning and / or inclination + curvature + positioning.

[0142] In particular, in the method according to the invention, one or more or all of the available degrees of freedom may not be used for the individual surfaces used to form the overall surface. However, in the method according to the invention, the unused degrees of freedom may be available.

[0143] Furthermore, the overall surface can be formed by at least one group, preferably a majority, in particular more than 90 percent, of the surfaces.

[0144] In an advantageous development of the method according to the invention, surfaces that are inclined relative to one another can be positioned and / or curved relative to one another such that the gap between adjacent surfaces that are inclined relative to one another is reduced, preferably minimized.

[0145] As a result, due to the reduction of the gap, regions are obtained on the overall surface of the optical device where the incident light is only slightly obstructed by the gap. These regions can be formed by one, several, or all of the plurality of optically active surfaces.

[0146] The reduction of the gap improves the optical performance of the overall surface formed cumulatively and organizationally.

[0147] It is advantageous to position and / or curve surfaces that are inclined relative to one another such that the gap between adjacent surfaces that are inclined relative to one another is minimized.

[0148] When the gap between adjacent surfaces that are inclined relative to one another is minimized by this method, this leads to a further improvement in the optical properties of each cumulative overall surface.

[0149] Furthermore, at least some of the surfaces forming the overall surface may not be inclined.

[0150] It is advantageous to incline the surfaces such that each surface is inclined relative to the initial direction of the average surface normal, to curve the surfaces such that each surface curves, and / or to position the surfaces such that each surface moves parallel to the plane relative to the initial position.

[0151] Moving each surface vertically in a plane-parallel manner is understood to mean a translational movement of the surface occurring along the initial direction.

[0152] It is advantageous if the inclination and / or curvature and / or positioning of the surface is carried out by separate devices that can be controlled independently.

[0153] By controlling the inclination, curvature, and positioning independently, the resulting degrees of freedom can be set independently of each other. In particular, the method of such an embodiment can utilize the degrees of freedom available due to the inclination and / or curvature and / or positioning independently.

[0154] It may be advantageous to position and / or curve the overall surface such that the gap between adjacent surfaces inclined with respect to each other of the overall surface decreases, preferably is minimized, while maintaining the specified inclination of the individual surfaces.

[0155] In this way, for example, it is possible to realize the position of the focus in space without changing the inclination of the controlled surface assembly.

[0156] In particular, the method steps of inclination and / or curvature and / or positioning can be repeatedly executed one after another, and in some cases, can be executed multiple times such that the overall surface gradually assumes the desired shape by the overall control device.

[0157] It is advantageous if the surface curves along at least two axes such that at least two radii of curvature are obtained for each surface.

[0158] Curving the surface along at least two axes such that there are at least two curvatures on the surface has the advantage that any curvature of the surface can be represented at least substantially as a linear combination of the two principal curvatures by the two principal curvatures.

[0159] Here, it is particularly advantageous if at least two axes do not coincide. Preferably, the two axes are perpendicular to each other.

[0160] When three or more axes are provided, it is advantageous if they are symmetrically arranged, preferably such that all surface normals passing through the center of the area intersect the surface.

[0161] Furthermore, it may be advantageous to curve the surface by expanding and / or contracting at least one actuator element arranged below the surface.

[0162] The curvature produced by the actuator element has the advantages that the actuator element is space-saving, easy to control, and can be implemented, in particular, by, for example, a piezo element.

[0163] MEMS technology, as a sub-field of microsystem technology, enables electrically controlled mechanical systems to be implemented on a very small scale with a lower size scale limit of 1 μm. Such small structures can be implemented, for example, by coating technology. For this purpose, small-scale structures are applied to each other as layers and / or etched away.

[0164] Therefore, it is advantageous for the method according to the invention that the overall surface is formed from a plurality of surfaces that are cooperatively tilted and / or curved and / or shifted.

[0165] The individual surfaces are cooperatively and / or systematically combined to form the overall surface, the surfaces are positioned in particular relative to each other, and the surfaces are cooperatively tilted and / or curved and / or shifted, so that it is possible to ensure that the overall surface functions as a single optically active surface. As a result, the overall surface, which functions as a single optical element, can be formed by a plurality of individual surfaces to which the overall surface can be assigned as individual optical elements, for example, by forming a common surface of these individual surfaces.

[0166] For example, the surfaces can interact such that the overall surface acts like a parabolic mirror having a single focus over the entire surface. Such an effect on the overall surface of a facet mirror according to the prior art is not possible with a simple inclination of the surface, even when coordinated.

[0167] It is advantageous if the surfaces are coordinatedly inclined and / or curved and / or shifted such that at least a substantially smooth overall surface is formed.

[0168] When at least a substantially smooth overall surface is formed, aberrations occurring at sharp gaps and / or edges and / or offsets can be reduced.

[0169] It is also advantageous if the overall surface is shaped such that one or more foci are formed.

[0170] When the overall surface is shaped such that one or more foci are formed, for example, multiple points on a pupil facet mirror can be irradiated with particularly high intensity by focusing.

[0171] It is advantageous if the overall surface is shaped such that the position and / or number of one or more foci changes during use of the device.

[0172] Preferably, the change can occur continuously and / or discontinuously.

[0173] The dynamic change of the overall surface has the advantage that it can respond to changes in requirements regarding the illuminance in various regions of the downstream optical unit. In particular, it is also advantageous if it is possible to respond to fluctuations in the light irradiating the overall surface and its intensity distribution by dynamic reshaping of the overall surface.

[0174] Furthermore, the dynamic change of the overall surface can also change the mixing of light between the field facet mirror and the pupil facet mirror during use.

[0175] An advantageous development of the method according to the invention can consist in changing the shape of the overall surface while shaping the wavefront using the overall surface.

[0176] In particular, for example, more than 100 surfaces, preferably more than 1000 surfaces, forming the overall surface can all be tilted and / or curved and / or positioned in less than 5 seconds, preferably in less than 2 seconds. In this case, additional surfaces that are not tilted, curved, or positioned can also contribute to the formation of the overall surface.

[0177] The invention also relates to a computer program product having program code means for executing the method according to the invention as described above and below when the program is executed on a device, in particular on an overall control device of an optical device according to the invention as described above and below.

[0178] The device can be designed as a microprocessor. Instead of a microprocessor, any further device for implementing the device can be provided, for example, one or more arrays of discrete electrical components on a printed circuit board, a programmable logic controller (PLC), an application-specific integrated circuit (ASIC), or any other programmable circuit, such as a field-programmable gate array (FPGA), a programmable logic array (PLA), and / or a commercially available computer.

[0179] The execution of the computer program product on a device provided for the verification of the operation and function in a lithography system, in particular in a projection exposure apparatus, and already implemented therein according to the prior art is particularly advantageous.

[0180] The invention further relates to a lithography system, in particular a projection exposure apparatus.

[0181] The lithography system according to the invention, in particular a microlithography projection exposure apparatus, comprises at least one optical element. According to the invention, at least one of the optical elements, in particular the field facet mirror and / or the pupil facet mirror, is formed by the optical device according to the invention and / or is controlled by the method according to the invention and / or according to the invention, a computer program product is provided which has program code means for executing the method according to the invention when the program is executed on a device, in particular on the overall control device of the optical device according to the invention.

[0182] It is advantageous that the features provided by the optical device according to the invention, the method according to the invention, the computer program product, and the lithography system, described in connection with one of the subjects of the invention, are also applicable to other subjects of the invention. Similarly, the advantages identified in connection with one of the subjects of the invention can also be understood in connection with other subjects of the invention.

[0183] It should be noted that terms such as "comprises", "has", or "includes" do not exclude other features or steps. Furthermore, words such as "a(n)" or "the" indicating a single step or feature do not exclude a plurality of features or steps, and vice versa.

[0184] However, in a pure embodiment of the invention, the features introduced into the invention using the terms "comprises", "has", or "includes" may be an exhaustive enumeration. Thus, one or more enumerations of features can be considered to be exhaustive within the scope of the invention, for example, when considered for each claim. As an example, the invention may consist only of the features described in claim 1.

[0185] Note that notations such as "first", "second", etc. are mainly used for the reason of being able to distinguish between the features of each device or method, and do not necessarily intend to indicate that the features are mutually required or related to each other.

[0186] Embodiments of the present invention will be described in more detail below with reference to the drawings.

[0187] The figures each show preferred embodiments in which the individual features of the invention are illustrated in combination with each other. The features of any embodiment can be implemented independently of the other features of the same embodiment and can be readily combined by those skilled in the art as appropriate to form further practicable combinations or sub - combinations with the features of other embodiments.

[0188] In the figures, functionally identical elements are given the same reference numerals.

Brief Description of the Drawings

[0189]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0190] First, referring to FIG. 1, the essential components of a micro-lithography EUV projection exposure apparatus 100 as an example of a lithography system will be illustratively described below. The description of the basic configuration of the EUV projection exposure apparatus 100 and its components should not be considered limited here.

[0191] The illumination system 101 of the EUV projection exposure apparatus 100 includes, in addition to the radiation source 102, an illumination optical unit 103 for illuminating the object field 104 of the object plane 105. What is exposed here is the reticle 106 disposed in the object field 104. The reticle 106 is held by the reticle holder 107. The reticle holder 107 is displaceable particularly in the scanning direction by the reticle displacement drive 108.

[0192] FIG. 1 shows an orthogonal xyz coordinate system for the purpose of explanation. The x direction extends perpendicular to the plane of the figure. The y direction extends horizontally, and the z direction extends vertically. The scanning direction extends in the y direction. The z direction extends perpendicular to the object plane 105.

[0193] The EUV projection exposure apparatus 100 includes a projection optical unit 109. The projection optical unit 109 functions to image the object field 104 onto the image field 110 of the image plane 111. The image plane 111 extends parallel to the object plane 105. Alternatively, an angle other than 0° is also possible between the object plane 105 and the image plane 111.

[0194] The structure on the reticle 106 is imaged onto the photosensitive layer of the wafer 112 disposed in the region of the image field 110 of the image plane 111. The wafer 112 is held by the wafer holder 113. The wafer holder 113 is displaceable particularly in the y direction by the wafer displacement drive 114. The displacement of the reticle 106 by the reticle displacement drive 108 first and the displacement of the wafer 112 by the wafer displacement drive 114 second can be implemented to be synchronized with each other.

[0195] The radiation source 102 is an EUV radiation source. The radiation source 102 emits EUV radiation 115, which is also particularly referred to as used radiation or illumination radiation hereinafter. In particular, the used radiation 115 has a wavelength in the range of 5 nm to 30 nm. The radiation source 102 can be a plasma source, such as an LPP ("laser-produced plasma") source or a GDPP ("gas-discharge plasma") source. It can also be a synchrotron-based radiation source. The radiation source 102 can be a free-electron laser (FEL).

[0196] The illumination radiation 115 generated from the radiation source 102 is focused by the collector 116. The collector 116 can be a collector having one or more elliptical reflecting surfaces and / or hyperbolic reflecting surfaces. The illumination radiation 115 can be incident on at least one reflecting surface of the collector 116 at a grazing incidence (GI), i.e., an incident angle greater than 45°, or at a normal incidence (NI), i.e., an incident angle less than 45°. The collector 116 can be structured and / or coated in order to optimize the reflectivity for the used radiation 115 first and to suppress the extraneous light second.

[0197] Downstream of the collector 116, the illumination radiation 115 propagates through the intermediate focus of the intermediate focal plane 117. The intermediate focal plane 117 can represent the separation between the radiation source module having the radiation source 102 and the collector 116 and the illumination optical unit 103.

[0198] The illumination optical unit 103 includes a deflection mirror 118 and a first facet mirror 119 disposed downstream thereof in the beam path. The deflection mirror 118 can be a planar deflection mirror or a mirror having a beam influence effect exceeding a pure deflection effect. Alternatively or additionally, the deflection mirror 118 can be embodied in the form of a grammar filter that separates the use light wavelength of the illumination radiation 115 from extraneous light of a wavelength deviating therefrom. When the first facet mirror 119 is disposed in the plane of the illumination optical unit 103 that is optically conjugate with the object plane 105 as the field plane, it is also referred to as the field facet mirror. The first facet mirror 119 includes a plurality of individual first facets 120, which are also referred to below as field facets. Only some of these facets 120 are exemplarily shown in FIG. 1.

[0199] The first facet 120 can be embodied in the form of a macroscopic facet, particularly in the form of a rectangular facet, or in the form of a facet having an arcuate peripheral contour or a partial circular peripheral contour. The first facet 120 can be embodied as a planar facet or as a convexly or concavely curved facet.

[0200] As is known, for example, from German Patent Application Publication No. 10 2008 009 600, the first facet 120 itself can also be composed of a plurality of individual mirrors, particularly a plurality of micromirrors. In particular, the first facet mirror 119 can be embodied as a microelectromechanical system (MEMS system). For details, reference is made to German Patent Application Publication No. 10 2008 009 600.

[0201] The illumination radiation 115 travels horizontally, i.e., longitudinally with respect to the y direction, between the collector 116 and the deflection mirror 118.

[0202] In the beam path of the illumination optical unit 103, a second facet mirror 121 is arranged downstream of the first facet mirror 119. When the second facet mirror 121 is arranged on the pupil plane of the illumination optical unit 103, it is also referred to as a pupil facet mirror. The second facet mirror 121 can also be arranged away from the pupil plane of the illumination optical unit 103. In this case, the combination of the first facet mirror 119 and the second facet mirror 121 is also referred to as a specular reflector. The specular reflector is known from US Patent Application Publication No. 2006 / 0132747, European Patent No. 1 614 008, and US Patent No. 6,573,978.

[0203] The second facet mirror 121 includes 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.

[0204] Similarly, the second facets 122 can be macroscopic facets having, for example, circular, rectangular, or hexagonal boundaries, or can be facets composed of micromirrors. In this regard, reference is made to German Patent Application Publication No. 10 2008 009 600.

[0205] The second facets 122 can have a planar reflecting surface, or a reflecting surface curved convexly or concavely.

[0206] As a result, the illumination optical unit 103 forms a double-facet system. This basic principle is also referred to as a fly-eye integrator.

[0207] It may be advantageous not to accurately arrange the second facet mirror 121 in a plane optically conjugate to the pupil plane of the projection optical unit 109.

[0208] Using the second facet mirror 121, the individual first facets 120 are imaged onto the object field of view 104. The second facet mirror 121 is the last beam shaping mirror or the actual final mirror for the illumination radiation 115 in the beam path upstream of the object field of view 104.

[0209] In yet another embodiment (not shown) of the illumination optical unit 103, a transfer optical unit that particularly contributes to the imaging of the first facet 120 onto the object field of view 104 can be arranged in the beam path between the second facet mirror 121 and the object field of view 104. The transfer optical unit can include exactly one mirror or two or more mirrors arranged successively in the beam path of the illumination optical unit 103. In particular, the transfer optical unit can include 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).

[0210] In the embodiment shown in FIG. 1, the illumination optical unit 103 includes exactly three mirrors downstream of the collector 116, specifically, the deflection mirror 118, the field facet mirror 119, and the pupil facet mirror 121.

[0211] Since the deflection mirror 118 can also be omitted in yet another embodiment of the illumination optical unit 103, the illumination optical unit 103 can then have exactly two mirrors downstream of the collector 116, specifically, the first facet mirror 119 and the second facet mirror 121.

[0212] The imaging of the first facet 120 onto the object plane 105 by the second facet 122 or using the second facet 122 and the transfer optical unit is generally only an approximate imaging.

[0213] The projection optical unit 109 includes a plurality of mirrors Mi, which are numbered according to their arrangement in the beam path of the EUV projection exposure apparatus 100.

[0214] In the example shown in FIG. 1, the projection optical unit 109 includes six mirrors M1 to M6. Substitutions with four, eight, ten, twelve, or any other number of mirrors Mi are similarly possible. The penultimate mirror M5 and the final mirror M6 each have a passage aperture for the illumination radiation 115. The projection optical unit 109 is a double shielding optical unit. The projection optical unit 109 has an image-side numerical aperture that is greater than 0.5, may be greater than 0.6, and can be, for example, 0.7 or 0.75.

[0215] The reflective surface of the mirror Mi can be embodied as a freeform surface without an axis of rotational symmetry. Alternatively, the reflective surface of the mirror Mi can be designed as an aspherical surface with exactly one axis of rotational symmetry of the reflective surface shape. Similar to the mirrors of the illumination optical unit 103, the mirror Mi can have a highly reflective coating for the illumination radiation 115. These coatings can be designed in particular as multilayer coatings having alternating layers of molybdenum and silicon.

[0216] The projection optical unit 109 has a large object-image offset in the y direction between the y coordinate of the center of the object field 104 and the y coordinate of the center of the image field 110. This object-image offset in the y direction can be substantially the same size as the z distance between the object plane 105 and the image plane 111.

[0217] In particular, the projection optical unit 109 can have an anamorphic embodiment. In particular, this has different imaging scales βx, βy in the x and y directions. The two imaging scales βx, βy of the projection optical unit 109 are preferably (βx, βy) = (+ / - 0.25, + / - 0.125). A positive imaging scale β means imaging without image inversion. A negative sign of the imaging scale β means imaging with image inversion.

[0218] As a result, the projection optical unit 109 reduces its size in the x direction, i.e., in the direction perpendicular to the scanning direction, by a ratio of 4:1.

[0219] The projection optical unit 109 reduces the size by a factor of 8 in the y direction, i.e., the scanning direction.

[0220] Other imaging scales are similarly possible. Imaging scales with the same sign and the same absolute value, for example, an absolute value of 0.125 or 0.25, in both the x and y directions are also possible.

[0221] 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 may be the same or different depending on the embodiment of the projection optical unit 109. An example of a projection optical unit with different numbers of such intermediate image planes in the x and y directions is known from US Patent Application Publication No. 2018 / 0074303.

[0222] 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. In particular, illumination according to Köhler's principle can thereby be obtained. The far field is decomposed into a plurality of object fields 104 using the field facets 120. The field facets 120 generate a plurality of images of the intermediate focus for the pupil facets 122 assigned thereto.

[0223] Due to the assigned pupil facets 122, the field facets 120 are imaged onto the reticle 106 overlappingly for the purpose of illuminating the object field 104. The illumination of the object field 104 is particularly as uniform as possible. The uniformity error is preferably less than 2%. By overlapping different illumination channels, field uniformity can be obtained.

[0224] The illumination of the entrance pupil of the projection optical unit 109 can be geometrically defined by the arrangement of the pupil facets. By selecting a light - guiding illumination channel, particularly a subset of the pupil facets, it is possible to set the intensity distribution at the entrance pupil of the projection optical unit 109. This intensity distribution is also referred to as the illumination setting.

[0225] Similarly favorable pupil uniformity in the defined illumination portion region of the illumination pupil of the illumination optical unit 103 can be achieved by redistribution of the illumination channels.

[0226] Further aspects and details of the illumination of the object field of view 104, in particular of the entrance pupil of the projection optical unit 109, will be explained below.

[0227] The projection optical unit 109 can in particular have a concentric entrance pupil. This can be made accessible. This can also be made inaccessible.

[0228] The entrance pupil of the projection optical unit 109 generally cannot be accurately illuminated using the pupil facet mirror 121. When imaging the projection optical unit 109 with the center of the pupil facet mirror 121 imaged telecentrically onto the wafer 112, the aperture rays often do not intersect at a single point. However, it is possible to find the surface area where the distance determined for pairs of aperture rays is minimized. This surface area represents the entrance pupil or the region within the real space conjugate thereto. In particular, this surface area has a finite curvature.

[0229] The projection optical unit 109 may have different entrance pupil positions for the tangential beam path and the sagittal beam path. In this case, an optical component of the imaging element, in particular of the transfer optical unit, should be provided between the second facet mirror 121 and the reticle 106. Using this optical component, it is possible to take into account the difference in the positions of the tangential entrance pupil and the sagittal entrance pupil.

[0230] In the arrangement of the components of the illumination optical unit 103 shown in FIG. 1, the pupil facet mirror 121 is arranged in the surface area conjugate to the entrance pupil of the projection optical unit 109. The first field facet mirror 119 is arranged to be inclined with respect to the object plane 105. The first facet mirror 119 is arranged to be inclined with respect to the arrangement plane defined by the deflection mirror 118.

[0231] The first facet mirror 119 is arranged to be inclined with respect to the arrangement plane defined by the second facet mirror 121.

[0232] FIG. 2 shows an exemplary DUV projection exposure apparatus 200. The DUV projection exposure apparatus 200 includes an illumination system 201, a device known as a reticle stage 202 that houses and accurately positions a reticle 203 that determines the subsequent structure on a wafer 204, a wafer holder 205 that holds, moves, and accurately positions the wafer 204, and an imaging device having a plurality of optical elements, particularly lens elements 207, specifically a projection optical unit 206. The lens elements 207 are held by mounts 208 in a lens housing 109 of the projection optical unit 206.

[0233] As an alternative to or in addition to the illustrated lens elements 207, various refractive, diffractive, and / or reflective optical elements, particularly mirrors, prisms, end plates, etc. can be provided.

[0234] In the basic functional principle of the DUV projection exposure apparatus 200, the structure introduced into the reticle 203 is imaged onto the wafer 204.

[0235] The illumination device 201 supplies a projection beam 210 in the form of electromagnetic radiation necessary for imaging the reticle 203 onto the wafer 204. The source used for this radiation can be a laser, a plasma source, etc. The radiation is shaped by optical elements in the illumination system 201 so that the projection beam 210 has desired characteristics regarding diameter, polarization, shape of the wavefront, etc. when incident on the reticle 203.

[0236] The image of the reticle 203 is generated by the projection beam 210 and transferred from the projection optical unit 206 to the wafer 204 in an appropriately reduced form. In this case, since the reticle 203 and the wafer 204 can be moved synchronously, each region of the reticle 203 is imaged onto the corresponding region of the wafer 204 substantially continuously during a so-called scanning operation.

[0237] The gap between the final lens element 207 and the wafer 204 can be optionally replaced with a liquid medium having a refractive index greater than 1. The liquid medium can be, for example, high-purity water. Such a configuration is also referred to as immersion lithography and has a high photolithography resolution.

[0238] The use of the present invention is not limited to use in a lithography system, nor to use in projection exposure apparatuses 100 and 200, nor particularly to a projection exposure apparatus having the described configuration. However, the present invention is particularly suitable for a lithography system, particularly a projection exposure apparatus, particularly a projection exposure apparatus having the described configuration. The present invention and the following exemplary embodiments should not be understood as being limited to a specific design. The following figures show the present invention very schematically as merely an example.

[0239] FIG. 3 shows a schematic view of an apparatus 1 according to the invention having a plurality of optically active surfaces 2, the surfaces 2 being tiltable respectively by separate autonomously controllable actuators 3 assigned to the surfaces 2. Here, the actuator 3 is also configured to position and / or curve the surface, and an overall control device 4 is provided for controlling the actuator 3 such that at least two of the surfaces 2 interact in a planned and coordinated manner to form an overall surface 5.

[0240] In the exemplary embodiment shown in FIG. 3, the optical device 1 is designed as a faceted mirror, preferably as a field faceted mirror 119, and reflects light emerging from the light source 6 to a target location 7 on the target structure 8, for example to the pupil facet 122 of the pupil faceted mirror 121. In particular, it may be intended that the focus of the surface 2, designed, for example, as a concave mirror, be positioned at the target location.

[0241] Furthermore, in the exemplary embodiment of the optical device 1 shown in FIG. 3, the overall control device 4 is preferably designed to control the actuator 3 such that the gap 9 between adjacent surfaces 2 is reduced by the tilt and / or positioning and / or curving of the surface 2.

[0242] Furthermore, in the exemplary embodiment of the optical device 1 shown in FIG. 3, it is preferable that the overall control device 4 controls the operating device 3 such that the gap 9 between adjacent surfaces 2 is minimized.

[0243] In the exemplary embodiment shown in FIG. 3, at least some of the surfaces 2 have a reflective layer system formed on at least a part of each surface 2.

[0244] The surface 2 is further hexagonal or triangular or rectangular, preferably square.

[0245] Furthermore, the surface area of the surface 2 is 0.5 mm 2 ~10 mm 2 preferably 0.9 mm 2 ~2 mm 2 and particularly preferably 1 mm 2 is.

[0246] FIG. 4 shows a schematic view of the optical device 1 with the surface 2 only tilted by the operating device 3.

[0247] FIG. 5 shows a schematic view of the optical device 1 with the surface 2 tilted and positioned in a planned and coordinated manner by the operating device 3, thus forming the overall surface 5.

[0248] In the exemplary embodiment of FIG. 5, the gap 9 between adjacent surfaces is reduced.

[0249] FIG. 6 shows a schematic view of the optical device 1 with the surface 2 tilted, positioned, and curved in a planned and coordinated manner by the operating device 3, thus forming the overall surface 5.

[0250] The surface 2 of the optical device 1 can also be tilted and curved in a planned and coordinated manner by the operating device 3 (not shown separately) to form the overall surface.

[0251] In the exemplary embodiments shown in FIGS. 4, 5, and 6, the surface 2 and the operating device 3 are arranged in a common body 17.

[0252] In the exemplary embodiment shown in FIG. 6, since the gap 9 between adjacent surfaces is minimized, the surfaces 2 are adjacent to each other at least substantially seamlessly.

[0253] FIG. 7 shows an exemplary embodiment of the surface 2 and the operating device 3 assigned to the surface 2.

[0254] In the exemplary embodiment shown in FIG. 7, the operating device 3 has an inclination device 10 for inclining the surface 2 with respect to the initial direction of the average surface normal 11 of the surface 2. Further, the operating device 3 has a curvature device 12 for curving the surface 2. Further, the operating device 3 has a positioning device 13 for moving the surface 2 up and down in a plane parallel to the initial position, and the inclination device 10 as well as the curvature device 12 and / or the positioning device 13 are designed as separate devices.

[0255] In the exemplary embodiment shown in FIG. 7, the operating device 3 includes an inclination control device 14 for controlling the inclination device 10, a positioning control device 15 for controlling the positioning device 13, and / or a curvature control device 16 for controlling the curvature device 12.

[0256] In the exemplary embodiment shown in FIG. 7, the inclination control device 14, the positioning control device 15, and the curvature control device 16 are designed separately. In an exemplary embodiment not shown, the inclination control device 14, the positioning control device 15, and the curvature control device 16 may be designed as part of an overall control device 4.

[0257] Furthermore, in the exemplary embodiment shown in FIG. 7, the surface 2 is designed to reflect light, in particular EUV light.

[0258] The surface 2 is arranged on a body 17 that serves as a common body 17 for all the surfaces 2 of the optical device 1. Alternatively, the body 17 can also serve as their base for arranging only some of the surfaces.

[0259] In an exemplary embodiment of the optical device 1 shown in FIG. 3, the overall control device 4 is further configured to approximate a desired shape of the overall surface 5 by the surface 2 by controlling the tilting device 10, the bending device 12, and the positioning device 13.

[0260] In this exemplary embodiment, the tilting device 10, the bending device 12, and the positioning device 13 are preferably designed according to an exemplary embodiment of the operating device 3 shown in FIG. 7.

[0261] In the exemplary embodiment shown in FIG. 7, the tilting device 10, the bending device 12, and the positioning device 13 are arranged between the main body 17 and each surface 2.

[0262] The bending device 12 is arranged between the surface 2 and the tilting device 10.

[0263] Furthermore, the positioning device 13 is arranged between the tilting device 10 and the main body 17.

[0264] In the exemplary embodiment shown in FIG. 7, the tilting device 10, the bending device 12, and the positioning device 13 assigned to one of the surfaces 2 are preferably connected to the main body 17 and each surface 2, and also preferably functionally and / or physically connected to each other.

[0265] Furthermore, in the exemplary embodiment shown in FIG. 7, the tilting device 10, the bending device 12, and the positioning device 13 are designed using MEMS technology (Micro-Electro-Mechanical System technology).

[0266] In an exemplary embodiment, the surface 2 is formed on a surface body 18 with a thickness of 1 μm to 500 μm.

[0267] FIGS. 8 and 9 show an exemplary embodiment of the bending device 12.

[0268] The bending device 12 is preferably formed as a piezo element by at least one expandable and / or contractable actuator element 19 in this case.

[0269] The bending device 12 is preferably formed by at least two, preferably at least four, actuator elements 19 arranged along at least two axes.

[0270] FIG. 8 shows an exemplary embodiment of the bending device 12 in which the actuator elements 19 are arranged spaced apart from the surface body 18 on the side opposite to the surface 2 of the surface body 18.

[0271] In this case, a reinforcing element 19a that improves the curvature of the surface 2 around the central region of the surface 2 is arranged between the actuators 19. Thus, for example, the surface 2 can take the shape of a concave mirror.

[0272] In particular, in an exemplary embodiment, the bending device 12 is arranged on the tilting device 10 using the reinforcing element 19a.

[0273] In the exemplary embodiment shown in FIG. 8, two actuator elements 19 are arranged parallel to the surface 2 along the axis. The actuator element 19 and the surface body 18 are separated from each other, and are spaced apart so that, for example, the surface body 18, and thus the surface 2, can be curved by the contraction of the actuator element 19. With this distance, this can be done while substantially avoiding the bending of the actuator element 19, and as a result, for example, the wear of the actuator element is reduced.

[0274] FIG. 9 shows an exemplary embodiment of the bending device 12 in which the actuator elements 19 are arranged in direct contact with the surface body 18 on the side opposite to the surface 2 of the surface body 18.

[0275] In the exemplary embodiments of the bending device 12 shown in FIGS. 8 and 9, the bending device is configured to form a curvature of less than 20 1 / m, preferably 0.2 1 / m to 20 1 / m, preferably 0.5 1 / m to 4 1 / m, particularly 1 1 / m to 2 1 / m at the surface 2.

[0276] In an exemplary embodiment of the bending device 12 shown in FIGS. 8 and 9, the bending device is further configured to form at least two curvatures on the surface 2.

[0277] FIG. 10 shows a plan view of the surface body 18 on the side opposite to the surface 2.

[0278] Four actuator elements 19 are arranged in direct contact with the surface body 18 on the side opposite to the surface 2 of the surface body 18.

[0279] The surface body 18 and the associated surface 2 are square in this exemplary embodiment.

[0280] In an exemplary embodiment, the surface 2 curves along two non - coincident axes such that at least two radii of curvature of the surface 2 occur. In an exemplary embodiment, the two axes preferably extend perpendicular to each other.

[0281] In FIGS. 8, 9, and 10, the expansion and contraction directions of the actuator element 19 are indicated by double - headed arrows.

[0282] FIG. 11 shows a schematic cross - sectional view of an exemplary embodiment of the positioning device 13. By way of example, the tilting device 10 is arranged here on the positioning device 13, and the surface body 18 and the surface 2 are arranged on the tilting device 10.

[0283] In the exemplary embodiment shown in FIG. 11, the positioning device 13 is formed by a deflectable membrane 20 on the cavity 21, preferably electrostatically actuable.

[0284] The deflection direction of the membrane 20 is indicated by double - headed arrows in FIG. 11.

[0285] The optical device 1 shown in FIGS. 3 to 11 is particularly suitable for implementing a method of controlling an optical device 1 having a plurality of optically active surfaces 2 that can be autonomously controlled to be inclined respectively. In this method, at least two of the surfaces 2 are tilted and / or positioned and / or curved so that at least two of the surfaces 2 interact in a planned and coordinated manner to form the overall surface 5.

[0286] The surfaces 2 inclined with respect to each other are positioned and / or curved with respect to each other such that the gap 9 between adjacent surfaces 2 inclined with respect to each other is reduced, preferably minimized.

[0287] In particular, as shown in FIG. 6, the surfaces 2 inclined with respect to each other are appropriately positioned and / or curved with respect to each other such that the gap 9 between adjacent surfaces 2 inclined with respect to each other is minimized.

[0288] Possible configurations of the tilting device 10 that can also be used in the optical device 1 are known from the general prior art. In this regard, reference is particularly made to Patent Document 1. This document discloses, for example in FIG. 2, a displacement device formed using MEMS technology for pivoting a mirror element, which can be used as the tilting device 10. Further possible embodiments of the tilting device 10 are described in U.S. Patent No. 9,013,676 and U.S. Patent No. 7,538,471.

[0289] FIG. 12 shows a block diagram of an exemplary embodiment of the method according to the present invention.

[0290] In the coordination block 30, the tilting and / or curving and / or positioning of the surfaces 2 to form the overall surface 5 are planned and coordinated. In the tilting block 31, the curving block 32, and the positioning block 33, each surface 2 is tilted and / or curved and / or positioned to the extent specified by the coordination block 30 such that the surfaces 2 form the overall surface 5 in the result block 34.

[0291] In an exemplary embodiment described, the inclination and / or curvature and / or positioning of surface 2 are each performed by a separate device that can be controlled independently.

[0292] Furthermore, in order to control the inclination, curvature and / or positioning of each surface 2, each surface has its own control device. The overall control device 4 positions and / or curves the entire surface 2 as a whole so that the gap 9 between adjacent surfaces 2 that are inclined with respect to each other of the entire surface 5 is reduced, preferably minimized, while maintaining the specified inclination of the individual surfaces 2. It is provided to control all the surfaces 2 that form the entire surface 5.

[0293] In an exemplary embodiment of the method described, the surface 2 is curved along at least two axes so that at least two radii of curvature of each surface 2 are obtained.

[0294] The method is such that the entire surface 5 is formed from a plurality of surfaces 2 that are tilted and / or curved and / or shifted in a planned and coordinated manner.

[0295] It is also preferable to tilt and / or curve and / or shift the surfaces 2 in a coordinated manner so that at least a substantially smooth overall surface 5 is formed. In this case, the at least substantially smooth overall surface has a minimized gap 9 without gaps or sharp edges between the surfaces 2.

[0296] In the coordination block 30, the inclination, curvature and / or positioning of the surface 2 are determined such that the entire surface 5 is shaped so that one or more foci are formed in the result block 34.

[0297] Furthermore, the entire surface 5 is shaped so that the position and / or number of one or more foci change during the use of the device 1.

[0298] In order to stabilize the optical properties of the entire surface 5, for example, a sensor block 35 that measures the wavefront and / or inclination and / or curvature and / or position generated from the entire surface 5 is provided in the illustrated exemplary embodiment. The information recorded in the sensor block 35 is subsequently transferred to the feedback block 36, where a correction signal and / or a setting signal for the cooperation block 30 is transmitted based on the information and sent to the cooperation block 30. Subsequently, in the cooperation block, an update command for the control blocks 31, 32, and 33 is requested and transferred.

[0299] Therefore, the cooperation block 30, the inclination block 31, the curvature block 32, the positioning block 33, and the feedback block 36 can be regarded as part of an overall control block 37 that cooperatively implements the individual blocks.

[0300] The overall control block 37 or the individual blocks 30, 31, 32, 33, 36 of the overall control block can be implemented by the overall control device 4.

Explanation of Reference Numerals

[0301] 1 Optical device 2 Surface 3 Operating device 4 Overall operating device 5 Overall surface 6 Light source 7 Target location 8 Target structure 9 Gap 10 Inclination device 11 Surface normal 12 Curvature device 13 Positioning device 14 Inclination control device 15 Positioning control device 16 Curvature control device 17 Body 18 Surface body 19 Actuator element 19a Reinforcing element 20 Film 21 Cavity 30 Coordination Block 31 Inclination Block 32 Curvature Block 33 Positioning Block 34 Result Block 35 Sensor Block 36 Feedback Block 37 Overall Control Block 100 EUV Projection Exposure Device 101 Illumination System 102 Radiation Source 103 Illumination Optical Unit 104 Object Field of View 105 Object Plane 106 Reticle 107 Reticle Holder 108 Reticle Displacement Drive 109 Projection Optical Unit 110 Image Field of View 111 Image Plane 112 Wafer 113 Wafer Holder 114 Wafer Displacement Drive 115 EUV / Usage / Illumination Radiation 116 Collector 117 Intermediate Focus Plane 118 Deflection Mirror 119 First Facet Mirror / Field Facet Mirror 120 First Facet / Field Facet 121 Second Facet Mirror / Pupil Facet Mirror 122 Second Facet / Pupil Facet 200 DUV Projection Exposure Device 201 Illumination System 202 Reticle Stage 203 Reticle 204 Wafer 205 Wafer Holder 206 Projection Optical Unit 207 Lens Element 208 Mount 209 Lens Housing 210 Projection Beam Mi mirror

Claims

1. An optical device (1) having a plurality of optically active surfaces (2), wherein each of the surfaces (2) is tiltable by a separate autonomously controllable operating device (3) assigned to the surface (2), in the optical device (1), the operating device (3) is configured to position and curve the surface (2), and an overall control device (4) is provided for controlling the operating device (3) such that at least three of the surfaces (2) interact in a planned and coordinated manner to form a substantially smooth overall surface (5). An optical device characterized by that.

2. An optical device (1) having a plurality of optically active surfaces (2), wherein each of the surfaces (2) is tiltable by a separate autonomously controllable operating device (3) assigned to the surface (2), in the optical device (1), the operating device (3) is configured to position and curve the surface (2), and an overall control device (4) is provided for controlling the operating device (3) such that at least three of the surfaces (2) interact in a planned and coordinated manner to form a substantially smooth overall surface (5), and each surface (2) has its own control device (14, 15, 16) configured to control the tilt, curvature and positioning of the respective surface (2), and the overall control device (4) positions and curves the overall surface (5) while maintaining a defined tilt of each of the individual surfaces (2). An optical device characterized by controlling all of the surfaces (2) such that the gap (9) between adjacent surfaces (2) that are tilted relative to each other is reduced, preferably minimized.

3. In the optical device (1) according to claim 1 or 2, the overall control device (4) controls the operating device (3) such that the gap (9) between adjacent surfaces (2) that are tilted relative to each other is minimized by the positioning and curvature of the surfaces (2). An optical device characterized by that.

4. In the optical device (1) according to any one of claims 1 to 3, the operating device (3) has an inclination device (10) for inclining the surface (2) with respect to the initial direction of the average surface normal (11) of the surface (2), the operating device (3) has a curvature device (12) for curving the surface (2) and a positioning device (13) for moving the surface (2) up and down in a plane-parallel manner with respect to the initial position, and the inclination device (10), the curvature device (12) and the positioning device (13) are designed as separate devices.

5. In the optical device (1) according to claim 4, at least some of the surfaces (2) each have a reflective layer system formed on at least a part of each of the surfaces (2).

6. In the optical device (1) according to claim 4 or 5, the curvature device (12) is configured to form at least two curvatures on the surface (2).

7. In the optical device (1) according to any one of claims 4 to 6, the inclination device (10), the curvature device (12) and the positioning device (13) are formed using MEMS technology (microelectromechanical system technology).

8. In the optical device (1) according to any one of claims 4 to 7, the positioning device (13) is formed by a deflectable membrane (20) on a cavity (21), preferably electrostatically actuable.

9. In the optical device (1) according to any one of claims 4 to 8, the curvature device (12) is arranged between the surface (2) and the inclination device (10).

10. In the optical device (1) according to any one of claims 4 to 9, the positioning device (13) is arranged between the inclination device (10) and the body (17) on the side opposite to the surface (2).

11. In the optical device (1) according to any one of claims 1 to 10, the surface (2) has an area of 0.5 mm ２ to 10 mm ２ , preferably 0.9 mm ２ to 2 mm ２ , particularly preferably 1 mm ２ . An optical device characterized by this.

12. In the optical device (1) according to claim 1, each surface (2) has its own control devices (14, 15, 16) configured to control the inclination, curvature and positioning of each surface (2), and the overall control device (4) positions and curves all the surfaces (2) as a whole in such a manner that the gap (9) between adjacent surfaces (2) inclined with respect to each other of the overall surface (5) decreases, preferably is minimized, while maintaining the specified inclination of the individual surfaces (2). An optical device characterized by this.

13. A method for controlling an optical device (1) having a plurality of optically active surfaces (2), wherein each of the surfaces (2) is autonomously controllable to be inclined, and the surfaces (2) are inclined, positioned and curved so that at least three of the surfaces (2) interact in a planned and coordinated manner to generate a substantially smooth overall surface (5). A method characterized by this.

14. The method according to claim 13, wherein the surfaces (2) inclined with respect to each other are positioned and curved with respect to each other so that the gap (9) between adjacent surfaces (2) inclined with respect to each other decreases, preferably is minimized. A method characterized by this.

15. The method according to claim 13 or 14, wherein the inclination, curvature and positioning of each of the surfaces (2) are respectively performed by separate devices that are independently controllable. A method characterized by this.

16. The method according to any one of claims 13 to 15, wherein the surfaces (2) are positioned and curved as a whole such that the gap (9) between adjacent surfaces (2) inclined with respect to each other of the overall surface (5) decreases, preferably is minimized, while maintaining the defined inclination of the individual surfaces (2).

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