Method for producing a voltage-reduced composite component, composite component and system for semiconductor technology

Abstract

The invention relates to a method for producing a voltage-reduced composite component (25), comprising: providing a first component (26), providing a second component (27), and connecting a first surface (28) of the first component (26) to a second surface (29) of the second component (27) to form a joining surface (33). The method also comprises forming at least one hollow structure (30) in the second component (27), which hollow structure is spaced apart from the second surface (29), before the first component (26) is connected to the second component (27) at the joining surface (33). The invention also relates to a composite component (25) which is produced according to the method, and to a composite component (25), comprising: a first component (26) and a second component (27), which has a second surface (29), which is connected to a first surface (28) of the first component (26) at a joining surface (33). The second component (27) has a hollow structure (30) which is spaced apart from the joining surface (33).

Description

[0001] Stuttgart, November 17, 2025 SZ00401 PCT Rp / pt

[0002] Method for manufacturing a stress-reduced composite component, composite component and system of semiconductor technology

[0003] Reference to related registration

[0004] This application claims priority over German patent application DE 102024211945.8 of 16.12.2024, the entire disclosure content of which is incorporated by reference into this application.

[0005] Background of the invention

[0006] The invention relates to a method for producing a stress-reduced composite component, preferably for semiconductor technology equipment, in particular for EUV lithography equipment, comprising: providing a first component, providing a second component, and joining a first surface of the first component to a second surface of the second component to form a joining surface at which the two components are permanently connected. The invention also relates to a composite component produced by the method, and to a composite component comprising: a first component, which preferably has a mirror surface for reflecting radiation, in particular for reflecting EUV radiation, and a second component, wherein a first surface of the first component is joined to a second surface of the second component at a joining surface.The invention also relates to a semiconductor technology system, in particular an EUV lithography system, with at least one such composite component.

[0007] A composite structure for microlithography, in particular a wafer holding device comprising two or more components,

[0008] 2024P00872WO 17.11.25 SZ00401 PCT, whose surfaces are joined together, is described in W02008 / 017449A2. The joining of the components can be achieved using a variety of joining methods described in W02008 / 017449A2. The composite structure can have at least one, in particular closed, cavity. The cavity can be formed between the two components and can be designed to accommodate heating elements, built-in components, or as a cooling channel.

[0009] The incorporation of cooling channels between two components or layers of an optical element is also described in DE102019217530A1. The optical element disclosed therein has an optical surface and a first layer made of a first material with a first coefficient of thermal expansion and a second layer made of a second material with a second coefficient of thermal expansion, which are assembled along an interface. A cooling device extends along the interface. The cooling device can be formed by incorporating a cooling channel and / or a cooling channel section into a surface of the first and / or the second layer, wherein the incorporated cooling channel and / or the incorporated cooling channel section forms the cooling device when the first and the second layer are subsequently assembled along the interface.The assembly process can involve joining and / or blasting the first and second layers together. It is also possible to fully embed the cooling channels in the first layer or the second layer by drilling holes into the respective layer after the two layers have been assembled. The first layer's coefficient of thermal expansion is at least ten times lower than the second layer's. The first layer material can be titanium-doped fused silica in the form of ultra-low expansion glass or a glass-ceramic such as Zerodur. The second layer material can be fused silica.

[0010] 2024P00872WO 17.11.25 SZ00401 PCT WO2021115643A1 describes an optical element for reflecting radiation, comprising a substrate made of fused silica, in particular titanium-doped fused silica, or of a glass-ceramic. A channel is formed in the substrate, preferably through which a cooling medium can flow, and whose cross-sectional area is substantially constant over a length of at least 10 cm. The channel can be formed in the substrate by selective laser etching. It is possible for the substrate to have a joining surface where two or more substrate parts are joined together by a bonding process, for example, by high-temperature bonding, direct bonding, or silicate bonding.

[0011] Object of the invention

[0012] The object of the invention is to improve a method for manufacturing a composite component, as well as to provide a composite component with improved properties and a semiconductor technology system with such a composite component.

[0013] Subject matter of the invention

[0014] This problem is solved, according to a first aspect, by a method of the type mentioned above, further comprising: forming at least one hollow structure spaced away from the second surface in the second component before the first component, which preferably does not have a hollow structure, is joined to the second component at the joining surface. The hollow structure in the second component is spaced away from the joining surface of the composite component, i.e., it does not border the joining surface.

[0015] The inventors recognized that when the hollow structure is formed in the second component, stresses are generated that are transferred to the first component if the formation of the hollow structure in the second component continues after

[0016] 2024P00872WO 17.11.25 SZ00401 PCT The joining of the two components takes place as described in DE102019217530A1. If the first component has a mirror surface, the stresses generated by forming the hollow structure can lead to undesirable deformations of this mirror surface, which must be corrected. Forming the hollow structure in the second component can also be advantageous for other reasons, as described below.

[0017] It is possible that in a composite component for semiconductor technology, the first component should not have a hollow structure, i.e., it should be solid. This might be because the material of the first component is unsuitable for incorporating hollow structures, for example, because the material is brittle, or because the material of the first component is not suitable for certain manufacturing processes for the hollow structure. It can also be disadvantageous if a hollow structure is formed in the second component adjacent to the joining surface, for example, if the material of the first component should not come into contact with a material located in the hollow structure, such as a temperature control fluid (TCF). Even if the material of the first component is identical to that of the second component, it may be advantageous in certain cases to introduce a hollow structure into only one of the two components.

[0018] In one variant, the hollow structure in the second component is formed by material removal using pulsed laser radiation. A method for creating a hollow structure in a workpiece by material removal using pulsed laser radiation is described in W02023 / 0110816A2, which is incorporated in its entirety into this application by reference. In the method described therein, a material removal front is formed during the material removal process, which moves within the workpiece when creating the hollow structure.

[0019] 2024P00872WO 17.11.25 SZ00401 PCT is used. The ablation front is brought into contact with a fluid or rinsed with a fluid. The pulsed laser radiation is injected into the workpiece from a radiation entry point. The workpiece is made of a material that is at least partially transparent to the pulsed laser radiation, so that the pulsed laser radiation can be focused in a focal region within the volume of the workpiece.

[0020] In the process described here, the hollow structure is typically formed at least partially or section by section at a relatively short distance from the second surface, along which the joining surface runs. When producing the hollow structure by material removal using pulsed laser radiation, the second surface typically serves as the entry point for the laser radiation. Once the second component is joined to the first component at the joining surface to form the composite structure, it is necessary to direct the pulsed laser radiation through the first component and the joining surface into the volume of the second component. This complicates, or may even prevent, the production of the hollow structure using pulsed laser radiation. For this reason, it can be advantageous to introduce the hollow structure into the second component before joining.

[0021] The formation of the hollow structure by material removal using pulsed laser radiation can also be carried out in a manner other than that described in W02023 / 0110816A2, for example by selective laser etching, as described, for example, in the aforementioned WO2021115643A1, which is incorporated in its entirety by reference into this application.

[0022] Material removal using pulsed laser radiation is generally possible on materials for which there is a suitable laser wavelength with which the second component can be removed in its volume.

[0023] 2024P00872WO 17.11.25 SZ00401 PCT can be processed. Forming the hollow structure through mechanical material removal is also possible, for example by grinding and / or drilling. A further requirement for manufacturing the composite component is that the materials of the two components can be joined using a suitable joining process or that they can be prepared appropriately to create a permanent bond.

[0024] In another variant, the hollow structure is formed at a distance of at least 1 mm, preferably at least 3 mm, from the second surface of the second component. Depending on the method used to form the hollow structure, it may be advantageous if it is not formed too close to the second surface, as this could potentially lead to undesirable surface effects. The second surface often forms a planar area when the hollow structure is formed. If the second surface deviates from a planar geometry, the distance between the second surface and the hollow structure is determined at a given point on the surface along the normal direction of the second surface at that point.

[0025] In another variant, material is removed from the second surface of the second component to reduce the distance between the hollow structure and the second surface before the components are joined. It can be advantageous for the hollow structure to have a very small distance from the second surface, especially if the hollow structure is intended to regulate the temperature of the first component. Since the distance between the second surface and the hollow structure may not be arbitrarily small when forming the hollow structure (see below), the second component can be thinned after the hollow structure is formed, for example, by machining or other means. It goes without saying that

[0026] 2024P00872WO 17.11.25 SZ00401 PCT that the second component can also be machined on the second surface to prepare it for subsequent joining. The geometry of the second surface can also be appropriately adjusted (su) if necessary.

[0027] In another embodiment, the second component features a hollow structure through which a temperature control fluid flows. This structure preferably has a plurality of temperature control channels, and the temperature control channels are particularly preferably located, at least partially, at a distance of less than 3 mm, and especially less than 1 mm, from the joining surface after the two components have been joined. In this case, the second component serves to temperature control the first component. For this purpose, the hollow structure, and in particular the temperature control channels, are actively supplied with a temperature control fluid. The temperature control can cool and / or heat the first component. The temperature control channels run below the joining surface at a small distance from it, which can be within the range specified above. The hollow structure can have at least one curved section.

[0028] The temperature control channels are typically connected to a fluid distributor, which supplies the temperature control fluid to the channels, and to a fluid collector, which discharges the temperature control fluid from the channels. The fluid distributor can have multiple distribution channels branching off from an inlet channel. The fluid collector can also have multiple collector channels leading into an outlet channel; see, for example, W02023 / 0110816A2. It is also possible, in principle, for the cooling channels to be unconnected to a fluid collector or a fluid distributor that forms part of the hollow structure in the second component.

[0029] 2024P00872WO 17.11.25 SZ00401 PCT In another variant, the first component is machined, preferably contoured, to form a mirror surface before and / or after joining the components, with the mirror surface preferably being formed on a side of the first component facing away from the joining surface. In this variant, the first component of the composite component is a mirror substrate. The second component typically serves to temper the first component (so) and the composite component forms a mirror component.

[0030] When processing the first component, contouring is typically performed on its side facing away from the joining surface or the future joining surface to create the desired surface shape of the mirror surface. This contouring can involve mechanical processing, such as grinding and / or polishing. It can also include abrasive processing, such as ion and / or electron beam processing, and possibly tempering.

[0031] In another variant, processing the first component to form the mirror surface involves applying a coating for radiation reflection, particularly for EUV radiation. Depending on the substrate material and the wavelength of the radiation to be reflected by the mirror surface, a reflective coating may not be strictly necessary. However, if the mirror surface is intended for EUV radiation reflection, applying a reflective coating is mandatory. For example, the reflective coating for EUV radiation could be a multilayer coating consisting of alternating layers of two materials with different refractive indices.

[0032] 2024P00872WO 17.11.25 SZ00401 PCT It is possible to apply the reflective coating to the first component before the two components are joined at the joining surface. In this case, the contouring of the first component to form the mirror surface must also be carried out before joining the two components. Care must be taken to ensure that the reflective coating is not damaged by the joining process or by subsequent process steps. In particular, care must be taken to ensure that the reflective coating does not exceed a maximum temperature at which it degrades. Furthermore, any deformation of the first component or the mirror surface caused by the joining process cannot be easily corrected if the reflective coating is applied to the first component before joining.

[0033] Alternatively, the reflective coating can be applied to the first component only after the two components have been joined. In this case, it is generally advantageous to perform only minor pre-contouring on the first component before joining, for example, by shaping it into a substantially cuboid form with a suitable outer geometry. The first component, in the form of the pre-contoured cuboid, is then joined to the second component. The contouring or shaping of the first component, particularly its reflective surface, is preferably carried out only after the two components have been joined.

[0034] In another variant, the composite component undergoes a tempering treatment after joining. This tempering treatment can relax any stresses in the composite component that may have been caused by the joining process. If a reflective coating was applied to the first component before joining, the

[0035] 2024P00872WO 17.11.25 SZ00401 PCT composite component during tempering treatment should only be heated to temperatures below the maximum temperature at which the reflective coating degrades (so).

[0036] In another variant, the components are joined together during the formation of the joining surface without the use of an adhesive, preferably by high-temperature bonding, silicate bonding, or laser welding. If the composite component is to be operated in a vacuum environment, it is generally advantageous to forgo the use of an adhesive when creating the joint. Before joining without an adhesive, particularly before high-temperature bonding, the first surface of the first component can be blasted onto the second surface of the second component.

[0037] In high-temperature bonding, also known as direct bonding, two or more components, typically consisting primarily of one or more different glass materials, are heated to a temperature above the glass transition temperature of the glass material. The glass transition temperature is material-dependent and is typically around 1000°C or higher. When the glass transition temperature is exceeded, the glass enters a viscous state. This allows the respective surfaces of the components to melt, forming covalent bonds that cause the two components to permanently bond together at the joining surface without the use of an adhesive.

[0038] In silicate bonding, the surface areas involved are first joined using an alkaline liquid. A subsequent heat treatment drives out the moisture. In laser welding under

[0039] 2024P00872WO 17.11.25 SZ00401 PCT Using pulsed laser radiation, especially with pulse durations on the order of femtoseconds or picoseconds, glass materials can be joined together without the use of an adhesive. It is understood that other methods that do not require an adhesive can also be used to create the joint between the two components. It is further understood that the two components can alternatively be joined using an adhesive, e.g., an adhesive or a glass frit, e.g., in the form of a film or preform, or by means of a glass paste or glass solder paste.

[0040] In particular, one of the methods described in W02008 / 017449A2, which is incorporated in its entirety by reference into this application, may be used for the connection between the two components.

[0041] The joining surface formed when the two components are joined can be a flat surface, a curved surface, or a freeform surface. To create a joining surface with the desired geometry, the two components can be suitably machined or contoured on the first or second surface. Contouring to create a curved joining surface is particularly useful for ensuring a constant distance between the cooling channels and the curved mirror surface of a composite component in the form of a mirror.

[0042] Another aspect of the invention relates to a composite component manufactured according to the method described above or one of its variants. The composite component can, in particular, be a mirror component with an integrated temperature control cavity. However, it is also possible for the composite component to fulfill a non-optical function. For example, the composite component could be a holding device for mounting an object.

[0043] 2024P00872WO 17.11.25 SZ00401 PCT, for example, is used to hold a wafer, as described, for example, in the W02008 / 017449A2 cited at the beginning.

[0044] The invention also relates to a composite component of the type mentioned at the outset, wherein the second component has a hollow structure, preferably designed for flow of a temperature control fluid, which is spaced apart from the joining surface, and wherein the first component preferably does not include a hollow structure. As described above in connection with the method, it can be advantageous if the hollow structure is formed only in the second component and is spaced apart from the joining surface.

[0045] As described above, the joining surface can be a flat surface, a curved surface (especially a spherically curved surface), or a freeform surface. Even if the joining surface is formed without the use of an adhesive and both components are made of the same material, the joining surface is still recognizable on the composite component: In high-temperature bonding, for example, a layer with a thickness on the order of a few nanometers forms in the area of ​​the joining surface, exhibiting a different glass structure than the surrounding glass material. In laser welding, a weld seam is present on the joining surface. If the connection is made using an adhesive, such as a glass frit, the adhesive is detectable on the joining surface.

[0046] In one embodiment, the first component has a minimum thickness of 5 mm or less, preferably 4 mm or less, particularly preferably 3 mm or less, and / or the second surface extends laterally beyond the joining surface, wherein preferably the first component has a chamfer or a rounding at the edge of the first surface and / or the second component has a circumferential undercut around the joining surface. In particular, if the

[0047] Since the PCT composite component (2024P00872WO 17.11.25 SZ00401) is a mirror component, it is advantageous if the cooling channels of the hollow structure are located a short distance from the mirror surface. This can be achieved by ensuring that the first component has a low minimum thickness. The thickness of the first component is measured at a specific position on the mirror surface or on the side of the first component facing away from the joining surface, in the normal direction at that position. If the thickness of the first component is not constant, for example, because it has a curved mirror surface, the minimum thickness of the first component will differ from the maximum thickness of the first component. The maximum thickness of the first component should be 30 mm or less, preferably 20 mm or less, and particularly 10 mm or less.

[0048] Especially when the composite component is a mirror component with a thin first component, it is advantageous if all contours required for handling, such as holes, references, connections, etc., are located on or within the second component. The first component can therefore have a smaller lateral extent than the second component. This allows for material savings in the first component. This is particularly beneficial for a composite component in the form of a mirror component, as the material of the first component must be of exceptionally high quality, which results in high manufacturing costs for the first component.If the second surface extends laterally beyond the joining surface, a lateral edge of the first component rests on the typically flat surface of the second component, which can lead to the development of mechanical stresses. It is therefore generally advantageous if there is no sharp edge or corner on the lateral edge of the first component's surface. This can be achieved by forming a chamfer or rounding on the edge of the first surface. For the reduction of mechanical stresses...

[0049] 2024P00872WO 17.11.25 SZ00401 PCT stresses can also be addressed by creating a relief groove around the joining surface of the second component. This relief groove prevents an edge from resting on the joining surface and also facilitates centering of the first component relative to the second component.

[0050] In another embodiment, the first component and the second component are made of the same material, preferably the same glass material, or the first component is made of a first material and the second component is made of a second material, wherein a coefficient of thermal expansion of the first material is less than a coefficient of thermal expansion of the second material.

[0051] The two components can be made of the same (glass) material or of two or more different (glass) materials. The same glass material means that the glass material of both components has practically the same properties, for example, because both components were cut from the same glass blank.

[0052] Different glass materials are present, for example, when the glass material of the two components has practically different properties, or when the two components consist of different types of glass.

[0053] Particularly in the case of a mirror component whose surface heats up considerably due to the incident radiation, e.g., during irradiation with EUV radiation, it is advantageous if the coefficients of thermal expansion of the two materials differ as little as possible, since otherwise asymmetric deformation and thus an undesirable change in the surface shape can occur. It can therefore be beneficial if the two components are made of the same material.

[0054] 2024P00872WO 17.11.25 SZ00401 PCT It can be particularly advantageous for cost reasons if the material of the first component has a lower coefficient of thermal expansion than the second material. The first material is typically a zero-expansion material, for example, titanium-doped quartz glass or a glass-ceramic, which has a very low coefficient of thermal expansion (see DE102019217530A1). The second material can be the same material as the first. Even if the first and second materials were cut from the same glass blank, the two materials can differ in their physical properties or quality.For example, the second material can be cut from an area of ​​the glass blank that exhibits a larger spatial gradient of the coefficient of thermal expansion and / or a larger spatial gradient of the zero-crossing temperature than the first material. Furthermore, the spatially averaged deviation from a target zero-crossing temperature can be greater for the second material than for the first. The second material can also be a zero-expansion material with a slightly larger coefficient of thermal expansion or undoped quartz glass.

[0055] In a further embodiment, the hollow structure through which the temperature control fluid flows has a plurality of temperature control channels, which preferably extend at least partially at a distance of 10 mm or less, preferably 5 mm or less, and particularly 3 mm or less from the mirror surface, wherein the temperature control channels particularly preferably maintain a constant distance from the mirror surface, which is particularly curved, at least partially. As described above, it is advantageous for the temperature control channels to extend at a small distance from the mirror surface in order to effectively dissipate heat from the mirror surface. For uniform temperature control, it is possible

[0056] 2024P00872WO 17.11.25 SZ00401 PCT is advantageous if the cooling channels run at a constant distance from the mirror surface. With a curved mirror surface, it may be necessary for the cooling channels not to run in a straight line, but rather to have a curvature that follows the curvature of the mirror surface. Regardless, to achieve a constant distance between the cooling channels and the mirror surface, it is necessary to select the appropriate distance of the cooling channels to the joining surface or to contour the joining surface appropriately to realize the desired, generally constant, distance to the joining surface. For example, the joining surface can be flat, and the cooling channels can run in a straight line or, if necessary, follow the curvature of the mirror surface within the composite component. It is also possible that the joining surface is not flat and, for example, has a spherical geometry or forms a freeform surface (so).Depending on the type of joining process used, it is also possible to use a flat joining surface and to change the shape of the joining surface during joining, for example when joining is done by high-temperature bonding.

[0057] It is understood that the composite component described above can have more than two components. For example, another component can be connected to the second component or possibly to the first component.

[0058] Another aspect of the invention relates to a semiconductor technology system, in particular an EUV lithography system, which has at least one composite component designed as described above. For the purposes of this application, a semiconductor technology system is understood to be an optical system that can be used in the field of semiconductor technology. In addition to a projection exposure system or a lithography system used for the production of semiconductor devices, the semiconductor technology system could, for example, be an inspection system for inspecting components in such a system.

[0059] 2024P00872WO 17.11.25 SZ00401 PCT projection exposure system used photomask, hereinafter also referred to as reticule, for inspecting a semiconductor substrate to be structured, hereinafter also referred to as wafer, or a metrology system used for measuring a projection exposure system or parts thereof, for example, for measuring projection optics. As described above, the composite component can be an optical composite component, for example, a mirror component. However, it is also possible that it is a non-optical component, for example, a support structure for a wafer, for a mask, or the like.

[0060] Further features and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention, with reference to the figures in the drawing, which show details essential to the invention, and from the claims. The individual features can be implemented individually or in any combination in a variant of the invention.

[0061] drawing

[0062] Examples of implementation are shown in the schematic drawing and are explained in the following description. It shows

[0063] Fig. 1 schematically shows a projection exposure system for EUV projection lithography in meridional section.

[0064] Fig. 2 shows a schematic representation of a process flow for joining two components, one of which has a hollow structure for temperature control of the other component.

[0065] 2024P00872WO 17.11.25 SZ00401 PCT Fig. 3 is a schematic representation of a process flow analogous to Fig. 2, in which the other component, which does not have a hollow structure, is contoured before joining.

[0066] In the following description of the drawings, identical reference symbols are used for identical or functionally equivalent components.

[0067] The following section describes, with reference to Fig. 1, the essential components of an optical arrangement for EUV lithography in the form of a projection exposure system 1 for microlithography. The description of the basic structure of the projection exposure system 1 and its components is not intended to be restrictive.

[0068] One embodiment of a lighting system 2 of the projection exposure system 1 has, in addition to a light or radiation source 3, a lighting optic 4 for illuminating an object field 5 in an object plane 6. In an alternative embodiment, the light source 3 can also be provided as a separate module from the rest of the lighting system. In this case, the lighting system does not include the light source 3.

[0069] A reticule 7 located in the object field 5 is illuminated. The reticule 7 is held by a reticule holder 8. The reticule holder 8 can be moved, particularly in a scanning direction, via a reticule displacement drive 9.

[0070] 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. In Figure 1, the scan direction runs along the y-direction. The z-direction runs perpendicular to the object plane 6.

[0071] 2024P00872WO 17.11.25 SZ00401 PCT The projection exposure system 1 comprises a projection system 10. The projection system 10 serves to image the object field 5 onto an image field 11 in an image plane 12. A structure on the reticulum 7 is imaged onto a photosensitive layer of a wafer 13 located in the image plane 12 within the area of ​​the image field 11. The wafer 13 is held by a wafer holder 14. The wafer holder 14 can be displaced, in particular along the y-direction, via a wafer transfer drive 15. The displacement of the reticulum 7 via the reticulum transfer drive 9 and of the wafer 13 via the wafer transfer drive 15 can be synchronized with each other.

[0072] Radiation source 3 is an EUV radiation source. Specifically, radiation source 3 emits EUV radiation 16, which is also referred to below as useful radiation, illumination radiation, or illumination light. The useful radiation has a wavelength in the range between 5 nm and 30 nm. Radiation source 3 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 3 can be a free-electron laser (FEL).

[0073] The illumination radiation 16 emanating from the radiation source 3 is focused by a collector mirror 17. The collector mirror 17 can be a collector mirror with one or more ellipsoidal and / or hyperboloid reflective surfaces. The at least one reflective surface of the collector mirror 17 can be illuminated by the illumination radiation 16 at grazing incidence (Gl), i.e., with angles of incidence greater than 45°, or at normal incidence (NI), i.e., with angles of incidence less than 45°. The collector mirror 17 can

[0074] 2024P00872WO 17.11.25 SZ00401 PCT may be structured and / or coated on the one hand to optimize its reflectivity for useful radiation and on the other hand to suppress stray light.

[0075] After the collector mirror 17, the illumination radiation 16 propagates through an intermediate focus in an intermediate focal plane 18. The intermediate focal plane 18 can represent a separation between a radiation source module, comprising the radiation source 3 and the collector mirror 17, and the illumination optics 4.

[0076] The illumination optics 4 comprise a deflecting mirror 19 and, downstream of this in the beam path, a first faceted mirror 20. The deflecting mirror 19 can be a planar deflecting mirror or, alternatively, a mirror with an effect that influences the beam beyond the mere deflection effect. Alternatively or additionally, the deflecting mirror 19 can be designed as a spectral filter that separates a useful wavelength of the illumination radiation 16 from stray light of a different wavelength. The first faceted mirror 20 comprises a plurality of individual first facets 21, which are also referred to as field facets in the following. Only a few of these facets 21 are shown by way of example in Fig. 1. Downstream of the first faceted mirror 20 in the beam path of the illumination optics 4 is a second faceted mirror 22. The second faceted mirror 22 comprises a plurality of second facets 23.

[0077] The illumination optics 4 thus form a double-faceted system. This basic principle is also known as a honeycomb condenser (fly's eye integrator). With the aid of the second faceted mirror 22, the individual first facets 21 are imaged into the object field 5. The second faceted mirror 22 is the last beam-shaping, or indeed the last, mirror for the illumination radiation 16 in the beam path before the object field 5.

[0078] 2024P00872WO 17.11.25 SZ00401 PCT The projection system 10 comprises a plurality of mirrors Mi, which are numbered according to their arrangement in the beam path of the projection exposure system 1.

[0079] In the example shown in Fig. 1, the projection system 10 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 16. The projection system 10 is a double-obscured optical system. The projection optics 10 have an image-side numerical aperture greater than 0.3 or 0.5, and which can also be greater than 0.6, for example, 0.7 or 0.75.

[0080] The mirrors Mi, just like the mirrors of the lighting optics 4, can have a highly reflective coating for the lighting radiation 16.

[0081] Fig. 2 shows a process flow for the production of a composite component 25, which in the example shown is a mirror component. The mirror component 25 can, for example, form one of the mirrors Mi of the projection optics 10 of the EUV lithography system 1. The mirror component 25 consists of two components 26, 27, which in the example shown are made of titanium-doped quartz glass, which has a low coefficient of thermal expansion. The two components 26, 27 provided for the process are cut from the same glass blank and therefore consist of the same glass material. Alternatively, two components 26, 27 made of two different glass materials can be used. In particular, a glass material with a higher coefficient of thermal expansion can be used for the second component 27 than for the first component 26.

[0082] 2024P00872WO 17.11.25 SZ00401 PCT Before joining to form the mirror component 25, the two components 26, 27 are prepared. The first component 26 is pre-contoured, i.e., it is essentially provided in a cuboid or thin cylindrical shape. The size of the first component 26, in particular its length and width or diameter, can be adapted to the size of a mirror surface 34 that will be formed later on a top surface of the first component 26. Further preparation of the first component 26 is kept to a minimum.

[0083] A first surface 28 of the first component 26, where it is to be joined to a second surface 29 of the second component 27, is also prepared for the subsequent joining process. This preparation may include cleaning and, if necessary, smoothing the first surface 28. The second surface 29 of the second component 27 is prepared accordingly for the subsequent joining process. Before joining, the first surface 28 of the first component 26 and the second surface 29 of the second component 27 can be blasted together.

[0084] As can be seen in Fig. 2, a hollow structure 30 is formed in the second component 27 before joining. The hollow structure 30 has an inlet opening on one side surface for a temperature control fluid 31, indicated by an arrow. The hollow structure 30 is designed to allow flow of the temperature control fluid 31 and extends from the inlet opening to an outlet opening on an opposite side surface of the second component 27.

[0085] The hollow structure 30 has several cooling channels 32 that run below the second surface 29. In the example shown, the cooling channels 32 run in a straight line at a constant distance d from the flat second surface 29. The distance d from the second surface 29 is in

[0086] 2024P00872WO 17.11.25 SZ00401 PCT, the example shown is at approximately 3 mm. At their two opposite ends, the temperature control channels 32 transition into distribution channels and collector channels, respectively, which do not run parallel to the second surface 29 and lead away from it. In addition to the temperature control channel 32 shown in the sectional view of Fig. 2, the second component 27 has several further temperature control channels that are aligned parallel to the temperature control channel 32 shown in Fig. 2. The further temperature control channels are arranged laterally offset from the temperature control channel 32 at the same distance d from the second surface 29.

[0087] The hollow structure 30 is formed in the second component 27 by material removal using pulsed laser radiation. The irradiation of the pulsed laser radiation into the volume of the second component 27 creates a material removal front within the second component 27. To form the hollow structure 30, the material removal front is moved through the volume of the second component 27, as described, for example, in W02023 / 0110816A2. The hollow structure 30 can also be formed in the second component 27 by other means, for example, by selective laser etching.

[0088] Material removal using pulsed laser radiation makes it possible to create a hollow structure 30 with virtually any geometry in the second component 27. In principle, the hollow structure 30 in the second component 27 can also be created by purely mechanical processing; however, this type of processing generally does not allow for the production of curved channels or a hollow structure 30 with a geometry that deviates from a straight line.

[0089] In the material removal process shown, the pulsed laser radiation is directed through the second surface 29 into the second component 27. It has proven advantageous to maintain a minimum distance d.

[0090] 2024P00872WO 17.11.25 SZ00401 PCT between the second surface 29 and the hollow structure 30 is maintained, which is on the order of approximately 1 mm, 2 mm or above.

[0091] Since the distance d between the hollow structure 30 and the second surface 29 should be as small as possible for temperature control of the first component 26, in the example shown, the distance d is reduced after the hollow structure 30 has been produced by removing material from the second surface 29 before the two components 26, 27 are joined together. In the example shown, the distance d is thus reduced to a value of approximately 1 mm. The material removal from the second surface 29 of the second component 27 is carried out by mechanical machining in the example shown.

[0092] After the formation of the hollow structure 30 in the second component 27 and the material removal from the second surface 29, the second component 27 is permanently bonded to the first surface 28 of the first component 26 at the second surface 29, forming a flat joining surface 33. In the example shown, the permanent bond between the two components 26, 27 is achieved without the use of an adhesive. In this example, the two components 26, 27 are joined by high-temperature bonding, i.e., they are heated to a maximum temperature above the glass transition temperature, whereby the surfaces 28, 29 permanently bond to form the mirror component 25, creating the joining surface 33. Alternatively, the bond can be achieved in other ways, for example, by silicate bonding, laser welding, or by using an adhesive.

[0093] After high-temperature bonding, the mirror component 25 undergoes a tempering treatment by cooling it from its maximum temperature according to a predetermined temperature profile, resulting in a reduction of

[0094] 2024P00872WO 17.11.25 SZ00401 PCT stresses in the mirror component 25. For this purpose, the mirror component 25 can be held at a predetermined holding temperature for a specified period of time.

[0095] After joining the two components 26, 27, the first component 26 of the mirror component 25 is machined to form a mirror surface 34, more precisely contoured, whereby a desired geometry of the first mirror surface 34 is created by removing material from the first component 26. After contouring, i.e., after forming the mirror surface 34, the first component 26 has a constant thickness D of approximately 5 mm. Subsequently, a reflective coating 35 is applied to the mirror surface 34 of the first component 26. This coating is designed to reflect EUV radiation 16 and, in the example shown, is a multi-layer coating.

[0096] The second surface 29 extends laterally beyond the joining surface 33, i.e., the second component 27 has a greater extent parallel to the joining surface 33 than the first component 26. The first component 26 may have a chamfer or a rounding at the edge of the first surface 28 to reduce mechanical stresses. Additionally or alternatively, the second component 27 may have a circumferential undercut around the joining surface 33. If the second component 27 has an undercut, this can be used to align the first component 26 with the second component 27. Attachments and connections for linking the hollow structure 30 to a temperature control device (not shown) may be mounted on the second component 27. The temperature control fluid 31 is configured to flow through the hollow structure 30 during operation of the mirror component 25 in the EUV lithography system 1.

[0097] 2024P00872WO 17.11.25 SZ00401 PCT In the example shown, the cooling channels 32 run at a distance D + d from the flat mirror surface 34, which corresponds to the sum of the thickness D of the first component 26 and the distance d of the cooling channels 32 from the joining surface 33. In the example shown, the distance D + d is approximately 5 mm, but it can also be smaller or larger. The distance D + d from the mirror surface 34 to the cooling channel 32 shown in Fig. 2, as well as to the other cooling channels (not shown) that run parallel to the cooling channel 32, is constant in the longitudinal direction of the cooling channels 32.

[0098] If the mirror surface 34 has a curvature, the cooling channels 32 can follow the curvature of the mirror surface 34 in order to maintain a constant distance to the mirror surface 34 in this case as well. It is possible that the joining surface 33 deviates from a planar geometry. For example, the joining surface 33 may have a curvature or it may be a freeform surface.

[0099] The process sequence shown in Fig. 3 differs from the process sequence shown in Fig. 2 for manufacturing the mirror component 25 in that the contouring of the first component 26 to form the mirror surface 34 takes place before joining the two components 26, 27 along the joining surface 33. The final processing of the mirror surface 34 and the coating of the first component 26 with the reflective coating 35 are carried out, as in Fig. 2, only after joining the two components 26, 27 to form the mirror component 25.

[0100] Instead of the mirror component 25, other composite components can also be formed in the manner described above, which can be used in the EUV lithography system 1 or in another semiconductor technology system. Such a composite component does not necessarily have to be an optical component. It can be

[0101] 2024P00872WO 17.11.25 SZ00401 PCT could also be a non-optical component, for example a holding component for a wafer or for a mask, or another mechanical component.

[0102] 2024P00872WO 11 / 17 / 25 SZ00401 PCT

Claims

Patent claims 1. Method for producing a stress-reduced composite component (25), preferably for a semiconductor technology system, in particular for an EUV lithography system (1), comprising: Providing a first component (26), Providing a second component (27), Joining a first surface (28) of the first component (26) with a second surface (28) of the second component (27) to form a joining surface (33), characterized by Form at least one hollow structure (30) spaced apart from the second surface (29) in the second component (27) before the first component (26), which preferably does not have a hollow structure, is joined to the second component (27) at the joining surface (33).

2. Method according to claim 1, wherein the hollow structure (30) in the second component (27) is formed by material removal using pulsed laser radiation.

3. Method according to claim 1 or 2, wherein the hollow structure (30) is formed at a distance (d) from the second surface (29) of the second component (27) which is at least 1 mm, preferably at least 3 mm.

4. Method according to one of the preceding claims, wherein, in order to reduce the distance (d) between the hollow structure (30) and the second surface (29), material is removed from the second surface (29) of the second component (27) before the components (26, 27) are joined together. 2024P00872WO 11 / 17 / 25 SZ00401 PCT 5. Method according to one of the preceding claims, wherein a hollow structure (30) through which a temperature control fluid (31) can flow is formed in the second component (27), which preferably has a plurality of temperature control channels (32), wherein the temperature control channels (32) particularly preferably run at least sectionally at a distance (d) of less than 3 mm, preferably less than 1 mm from the joining surface (33) after joining the two components (26, 27).

6. Method according to one of the preceding claims, in which, before and / or after joining the components (26, 27), the first component (26) is machined, preferably contoured, to form a mirror surface (34), wherein the mirror surface (34) is preferably formed on a side of the first component (26) facing away from the joining surface (33).

7. Method according to claim 6, wherein the processing of the first component (26) to form the mirror surface (34) comprises the application of a coating (35) for the reflection of radiation, in particular for the reflection of EUV radiation (16), to the first component (26).

8. Method according to one of the preceding claims, wherein the composite component (25) is subjected to a tempering treatment after joining.

9. Method according to one of the preceding claims, wherein the components (26, 27) are joined together during the formation of the joining surface (33) without the use of a joining agent, preferably by high-temperature bonding, by silicate bonding or by laser welding.

10. Composite component (25), preferably for a semiconductor technology system, in particular for an EUV lithography system (1), 2024P00872WO 11 / 17 / 25 SZ00401 PCT produced according to the method according to one of the preceding claims.

11. Composite component (25), preferably for a semiconductor technology system, in particular for an EUV lithography system (1), comprising: a first component (26), which preferably has a mirror surface (34) for reflecting radiation, in particular for reflecting EUV radiation (16), and a second component (27), which has a second surface (29) which is connected to a first surface (28) of the first component (26) at a joining surface (33), characterized in that the second component (27) has a hollow structure (30) preferably designed for flow with a temperature control fluid (31), which is spaced apart from the joining surface (33), wherein the first component (26) preferably does not have a hollow structure.

12. Composite component according to claim 10 or 11, wherein the first component (26) has a minimum thickness (D) of 5 mm or less, preferably 4 mm or less, particularly preferably 3 mm or less, and / or wherein the second surface (29) extends laterally beyond the joining surface (33), wherein preferably the first component (26) has a chamfer or a rounding at the edge of the first surface (28), and / or the second component (27) has an undercut running around the joining surface (33).

13. Composite component according to one of claims 10 to 12, wherein the first component (26) and the second component (27) are formed from the same material, preferably from the same glass material, or wherein the first component (26) is made from a first material and the second 2024P00872WO 11 / 17 / 25 SZ00401 PCT Component (27) are formed from a second material, wherein a thermal expansion coefficient of the first material is less than a thermal expansion coefficient of the second material.

14. Composite component according to one of claims 10 to 13, in which the hollow structure (30) through which the temperature control fluid (31) can flow has a plurality of temperature control channels (32) which preferably extend at least sectionally at a distance (D + d) of 10 mm or less, preferably of 5 mm or less, in particular of 3 mm or less from the mirror surface (34), wherein the temperature control channels (32) particularly preferably have at least sectionally a constant distance (D + d) to the particularly curved mirror surface (34).

15. Semiconductor technology system, in particular EUV lithography system (1) comprising: at least one composite component (25) according to any one of claims 10 to 14. 2024P00872WO 11 / 17 / 25 SZ00401 PCT

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