Optical component, method for mounting the optical component, projection exposure system

Abstract

Optical component (200) for EUV lithography, comprising a media-carrying pipe system (300, 307, 400, 406, 500, 508) for operation in a vacuum environment, wherein the media-carrying pipe system (300, 307, 400, 406, 500, 508) has at least one connection area (209) between a metallic section (207) and a section (205) consisting of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K, characterized in that that the connection area (209) is at least partially enclosed by an externally attached sealing device (210), wherein the sealing device (210) comprises a sealing element (211) and a fixing device (212) for attaching the sealing element (211) to the connection area (209), and wherein the sealing element comprises an elastomer.

Description

Field of the invention

[0001] The invention relates to an optical component for an EUV projection exposure system, comprising a media-carrying pipe system for operation in a vacuum environment, wherein the media-carrying pipe system has at least one connecting region between two sections and wherein the connecting region is at least partially enclosed by an externally applied sealing device.

[0002] The invention further relates to an EUV projection exposure system with at least one optical component and a method for assembling an optical component. Background of the invention

[0003] Projection exposure systems for EUV lithography are used to manufacture microstructured or nanostructured components in microelectronics or microsystems technology. To precisely produce components with extremely small structures in the nanometer and micrometer range, a corresponding projection exposure system must be able to precisely image structures contained on a reticle onto a substrate, such as a wafer.

[0004] Projection exposure systems designed for the EUV range typically use a wavelength of 13.5 nm to achieve the appropriate resolution on the substrate. Due to the lack of suitable transparent materials in this wavelength range, mirrors are used as optical components for the imaging process. Due to the low transmission of all gases at wavelengths in the 13.5 nm range, projection exposure systems designed in this way must be operated in a vacuum environment.

[0005] Due to the required resolution for EUV projection exposure systems, it is also necessary for the optical components of the EUV projection exposure system to exhibit the smallest possible temperature-induced elongation, so that no or only minimal deformation occurs during operation, especially of the optical surface. For this purpose, substrate materials are used for the optical components that exhibit an extremely low coefficient of linear expansion at operating temperature. Substrate materials used include quartz glass, titanium-doped quartz glass, or SiSiC.

[0006] To ensure the optical components operate as stably as possible at operating temperature, they can be designed with temperature control. For this purpose, reference is made to the document DE102017221388A1, which describes how cooling structures in optical components can be obtained from the described substrate materials. These cooling structures sometimes have connectors made of the same substrate materials as the mirror substrate itself. These connectors are connected to additional pipe sections for connection to an external media supply. Typically, such an external media supply is made of a metallic material, in particular stainless steel, aluminum, nickel, copper, or their alloys.

[0007] For example, internal sealing systems are known from the prior art for connecting different pipe sections using flange surfaces. Reference is made to the publications DE102022203254B3, DE102020208496A1, and DE102020208200A1. If such a flange-based connection is not possible due to design reasons, the substrate materials of the optical components, such as quartz glass, titanium-doped quartz glass, or SiSiC, must be directly connected, in particular by welding, soldering, bonding, or clamping, to metallic materials such as stainless steel, aluminum, nickel, copper, or their alloys.

[0008] However, due to external influences (e.g. during assembly or operation), such directly connected interfaces or connection areas between the substrate materials and the metallic materials can become leaky. Welded, soldered, and bonded components in particular have a solid connection that cannot be opened without damage. This requires repair by removing the leaking defect and re-applying the weld, solder, or bond. Such a repair process is usually very time-consuming and expensive. Furthermore, there is a risk that the defect cannot be eliminated by the repair. If the cause of the leak is unknown, it may recur in the subsequent process, even if the repair is successful.If such a leak in the optical component occurs during operation of the EUV projection exposure system, there is also a risk of significant damage to the EUV projection exposure system due to operation in a vacuum environment.

[0009] It is therefore an object of the invention to provide an improved optical component for an EUV projection exposure system and a method for assembling the same, which avoids the disadvantages described in the prior art and is suitable for operation in a vacuum environment.

[0010] This problem is solved according to the features of the independent patent claims. Disclosure of the invention

[0011] The optical component according to the invention for EUV lithography has a media-carrying tube system for operation in a vacuum environment, wherein the media-carrying tube system comprises at least one connecting region between a metallic section and a section consisting of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K. The connecting region is at least partially enclosed by an externally applied sealing device, wherein the sealing device comprises a sealing element and a fixing device fastening the sealing element to the connecting region, and wherein the sealing element comprises an elastomer. The sealing device successfully eliminates existing and potential leaks at the connection area. Such sealing devices are known from the prior art in the event of leaks for the repair of one-piece metallic piping systems (see, for example, WO15050428A1). The inventors have recognized that such sealing devices can be transferred to a media-carrying piping system of an optical component with a connection area between a metallic section and a section consisting of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K. Furthermore, it was surprisingly demonstrated that the sealing device is suitable for use within a vacuum environment necessary for the operation of optical components in EUV lithography, and in particular in an EUV plasma environment.A media-carrying pipe system means in particular a pipe system with a circular, square or triangular cross-section, but is not limited to this.

[0012] According to a first embodiment of the optical component, the sealing device comprises a shielding unit. The shielding unit is made, for example, of a metallic material, in particular of aluminum, copper, or stainless steel. The shielding unit can surround the sealing element and the fixing device, whereby the fixing device directly secures the sealing element to the connection area. Likewise, the shielding unit can be arranged between the sealing element and the fixing device. Particularly when the shielding unit is designed as a film, this arrangement can achieve a more stable fastening, since in this case the fixing device also secures the shielding unit.

[0013] The shielding unit improves the usability of the sealing device during operation in a vacuum environment and / or an EUV plasma environment within the EUV projection exposure system by encapsulating the sealing element or the sealing element and the fixing device. This may be particularly necessary in areas of the EUV projection exposure system with very high cleanliness requirements and / or EUV plasma density. The shielding unit advantageously prevents or minimizes outgassing and any potential interaction with the EUV-induced plasma of the sealing device.

[0014] According to one embodiment of the optical component, the sealing device has a mirror axis running parallel to the connection area. This results in a symmetrical design, as the two connected sections are mirrored in the connection area. The symmetrical design results in improved ease of assembly, as the sealing element can be installed in a twist-proof manner. Furthermore, a more uniform compressibility of the sealing element relative to the connection area is achieved.

[0015] According to one embodiment of the optical component, the media-carrying piping system is a water-carrying piping system for controlling the temperature of the optical component. For the best possible imaging properties, it is necessary that the substrate materials of the optical component according to the invention exhibit the smallest possible change in length during operation. For this purpose, substrate materials are used for the optical component that have an extremely low coefficient of linear expansion at operating temperature. The water-carrying piping system achieves particularly effective temperature control of the optical component, especially in the operating temperature range.

[0016] According to an alternative embodiment of the optical component, the media-carrying piping system is a gas-carrying piping system. This allows, for example, individual areas of the optical component to be exposed to a purge gas, such as nitrogen or hydrogen. These areas can provide and maintain the required cleanliness by purging within encapsulated volumes of the optical components. Alternatively, the purge gas can also be used for temperature control.

[0017] According to a particularly advantageous embodiment of the optical component, the connection area has a welded, soldered, glued, or clamped interface. These connection techniques are particularly suitable for connecting metallic and silicon-containing substrate materials.

[0018] According to a further embodiment of the optical component, the metallic section comprises stainless steel, aluminum, nickel, or copper. These materials are particularly suitable for the formation of media-carrying piping systems and are available in a wide variety of materials. For example, they are characterized by high resistance, particularly corrosion resistance, to the media used. They also exhibit low outgassing, which is advantageous for use in a vacuum environment, and high resistance to an EUV plasma environment. Furthermore, the materials are easy to clean and are therefore available with a correspondingly high degree of cleanliness.

[0019] According to one embodiment of the optical component, the section consisting of a silicon-containing substrate material comprises quartz glass, titanium-doped quartz glass, or SiSiC. These materials are particularly suitable as substrate materials for an optical component for EUV lithography. Some of them have an extremely small coefficient of linear expansion in the range of the operating temperature of the optical component. Furthermore, these substrates can be coated with various materials to achieve reflectivity of EUV radiation.

[0020] According to a particularly advantageous embodiment of the optical component, the sealing element comprises a fluorine-containing polymer, for example, a fluororubber or perfluororubber. These fluorine-containing polymers are characterized by good temperature resistance and are suitable for applications involving contact with aggressive media and / or high purity requirements. The sealing element can also be made of nitrile rubber, ethylene-propylene-diene rubber, or a tetrafluoroethylene-hexafluoropropylene copolymer.

[0021] According to one embodiment of the optical component, the fixing device comprises a clamp made of stainless steel. The clamp design ensures that the sealing element is evenly compressed at the connection area. A clamp is particularly suitable for a circular pipe geometry. The use of stainless steel makes the clamp suitable for use in a vacuum environment and easy to clean.

[0022] According to a particularly advantageous embodiment of the optical component, the clamp has an open thread for screwing. An open thread refers to a combination of a thread and a slotted hole separated at two connecting pieces of the clamp, whereby a screw used to fasten the clamp is completely removable, creating a gap between the connecting pieces when the clamp is open. This leaves the thread open with the screw removed. This further improves cleanability. Alternatively, an ear-tube clamp can be used.

[0023] Furthermore, the invention relates to a projection exposure system for EUV lithography, which has at least one optical component according to claims 1-11.

[0024] This results in the aforementioned advantages for the projection exposure system according to the invention. Further advantages and preferred features emerge from the above description and from the claims.

[0025] Furthermore, the invention relates to a method for assembling a sealing device for a connection region between a metallic section and a section consisting of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K of a media-carrying tube system of an optical component for a vacuum environment.

[0026] In a first step of the process, a mounting cone is provided at an open end of a first section. The mounting cone enables the bridging of a diameter difference between a sealing element and the first section of the media-carrying pipe system. The mounting cone is advantageously placed on the section with the smaller diameter of the two sections, so that the diameter difference to be bridged is as small as possible. The mounting cone can be made of stainless steel or an aluminum alloy, for example, or of plastics such as polyoxymethylene (POM) or polyetheretherketone (PEEK).

[0027] In a second step of the process, a sealing element is provided. The sealing element consists, for example, of a fluororubber or perfluororubber. The sealing element can also be made of nitrile rubber, ethylene-propylene-diene rubber, or a tetrafluoroethylene-hexafluoropropylene copolymer.

[0028] In a third step of the process, the sealing element is placed on the mounting cone at the open end of the first section.

[0029] In a fourth step of the process, the sealing element is pulled over the first section, moving it to the connecting area and enclosing it. Since the elastic sealing element has bridged any diameter difference relative to the first section for assembly by means of the assembly cone, the sealing element can conform to the surroundings of the connecting area.

[0030] In a fifth step of the method, a fixing device is provided. The fixing device can comprise a stainless steel clamp. Preferably, the clamp has an open thread according to the application, which makes it easier to clean.

[0031] In a sixth step of the method, the fixing device is attached to the sealing element in such a way that the fixing device at least partially encloses and compresses the sealing element, whereby the sealing device is obtained.

[0032] According to one embodiment of the inventive method, a shielding unit is provided in a seventh step. The shielding unit is made, for example, of aluminum, copper, or stainless steel. The shielding unit can also be designed as a film, thereby achieving more flexible adaptation to the sealing element. Subsequently, in an eighth step, the shielding unit is attached to the sealing device such that the shielding unit at least partially, in particular completely, encloses the sealing device. The shielding unit improves the usability of the sealing device and the optical component during operation in a vacuum environment and / or an EUV plasma environment within a projection exposure system by at least partially encapsulating the sealing element and the fixing device.This prevents or minimizes outgassing and possible interaction with the EUV-induced plasma of the sealing device.

[0033] According to an alternative embodiment of the inventive method, the shielding unit is provided after the fourth step, covering the sealing element, and is fastened to the sealing element such that it at least partially, in particular completely, encloses the sealing element. Subsequently, the fixing device is provided according to the fifth step and, in an alternative step, is fastened to the shielding unit and the underlying sealing element. In particular, if the shielding unit is designed as a film, this embodiment of the method can achieve a more stable fastening, since in this case the fixing device also acts as a fastening device for the shielding unit.

[0034] The invention will be explained in more detail below with reference to the drawings. Fig. 1 an EUV projection exposure system, Fig. 2 an optical component according to the invention for a projection exposure system Fig. 3a and Fig. 3b a media-carrying tube system of an optical component with a vacuum-compatible symmetrical sealing device for a connection area of ​​the tube system Fig. 4a and Fig. 4b a media-carrying tube system of an optical component with a vacuum-compatible asymmetric sealing device for a connection area of ​​the tube system Fig. 5a and Fig. 5b a media-carrying tube system of an optical component with a vacuum-compatible symmetrical sealing device comprising a shielding unit for a connection area of ​​the tube system Fig. 6a and Fig. 6b Process steps for the assembly of a sealing element as a component of a sealing device for a media-carrying pipe system Fig. 7 Process sequence of an embodiment of the inventive process Fig. 8 a clamp as a fixing element for fastening a sealing element to a connection area with an open thread for screwing.

[0035] Fig. 1 shows an example of the basic structure of an EUV projection exposure system 100 for semiconductor lithography.

[0036] An illumination system 101 of the projection exposure system 100 comprises, in addition to a radiation source 102, illumination optics 103 for illuminating an object field 104 in an object plane 105. A reticle 106 arranged in the object field 104 is illuminated and held by a reticle holder 107, a detail of which is shown schematically. Projection optics 108 serve to image the object field 104 into an image field 109 in an image plane 110. A structure on the reticle 106 is imaged onto a light-sensitive layer of a wafer 111 arranged in the region of the image field 109 in the image plane 110 and held by a wafer holder 112, also a detail of which is shown.

[0037] The radiation source 102 can emit EUV radiation 113, in particular in the range between 5 nanometers and 30 nanometers, in particular 13.5 nm. For this purpose, the radiation source has a collector mirror 126 as an optical component. To control the radiation path of the EUV radiation 113, optically differently designed and mechanically adjustable optical elements are used. The optical elements are Fig. The EUV projection exposure system 100 shown in Figure 1 is designed as adjustable mirrors in suitable embodiments mentioned below only as examples. Individual optical elements designed as mirrors can consist of several segments with separate optical sub-surfaces.

[0038] The EUV radiation 113 generated by the radiation source 102 is aligned by the collector mirror 126 integrated in the radiation source 102 such that the EUV radiation 113 passes through an intermediate focus in the region of an intermediate focal plane 114 before impinging on a field facet mirror 115. After the field facet mirror 115, the EUV radiation 113 is reflected by a pupil facet mirror 116. With the aid of the pupil facet mirror 116 and further optical components 117, 118, 119, field facets of the field facet mirror 115 are imaged into the object field 104. See US9411241B2 for details.

[0039] The reticle 106 arranged in the object field 104 can, for example, be a reflective photomask having reflective and non-reflective, or at least less highly reflective, regions for generating at least one structure on the reticle 106. Alternatively, the reticle 106 can be a plurality of micromirrors arranged in a one- or multi-dimensional component and optionally movable about at least one axis to adjust the angle of incidence of the EUV radiation on the respective mirror.

[0040] The reticle 106 reflects a portion of the beam path of the illumination optics 103 and forms a beam path in the projection optics 108, which radiates the information about the structure of the reticle 106 into the projection optics 108, which generates an image of the reticle 106 or a respective subregion thereof on the wafer 111 arranged in the image plane 110. The wafer comprises a semiconductor material, e.g., silicon, and is arranged on a wafer holder 112, which is also referred to as a wafer stage.

[0041] In the present example, the projection lens 108 has six reflective optical components 120 to 125, which are designed as mirrors to generate an image of the reticle 106 on the wafer 111. Typically, the number of mirrors in a projection lens such as 108 is between four and eight, but if necessary, only two or even ten mirrors can be used. Projection lenses are known from US2016 / 0327868A1 and DE102018207277A1.

[0042] Fig. 2 shows an optical component 200 for the projection exposure system 100, which, for example, Fig. 1. The optical component 200 is designed as a mirror, comprising a mirror substrate 201 onto which a reflective surface 202 is applied. Quartz glass, titanium-doped quartz glass, or SiSiC are used as the substrate material, which are typically characterized by a coefficient of linear expansion of less than 3 ppm / K. This achieves sufficiently good dimensional stability, particularly in the range of the operating temperature of the optical component 200. In order to make the operating temperature stably adjustable even under a high power density of the EUV radiation 113, the mirror substrate 201 is temperature-controlled. For this purpose, the mirror substrate 201 comprises a channel 203 through which media can flow. Gaseous and liquid substances can be used as media, in particular cooling media.For targeted media guidance, the channel 203 has an inlet piece 204 and an outlet piece 205. The inlet piece 204 and the outlet piece 205 are formed from the same material as the mirror substrate 201, for example, quartz glass, titanium-doped quartz glass, or SiSiC.

[0043] In order to connect the temperature-controlled mirror substrate 201 to an external media supply via the inlet piece 204 and the outlet piece 205, the inlet piece 204 and the outlet piece 205 are connected to metallic pipe sections 206 and 207. The metallic pipe section 206 is designed as the inlet and the metallic pipe section 207 as the outlet for possible media transport (see direction of the arrow) and are made, for example, of stainless steel, aluminum, nickel, copper, or their alloys. For the connection, connecting areas 208 and 209 are formed between the inlet piece 204 and the metallic pipe section 206, and between the outlet piece 205 and the metallic pipe section 207. For example, the inlet piece 204 and / or the outlet piece 205 are soldered, welded, or glued to the metallic sections 206 or 207. Such a device is known, for example, from DE102017221388 A1.

[0044] However, during operation or assembly, there is a risk that the connection areas 208 and / or 209 may be damaged or leaks may occur, for example, due to corrosion. Since the optical component 200 typically operates in a vacuum environment, this would compromise the vacuum.

[0045] Therefore, an external sealing device 210 is attached to the connecting region 209, which at least partially encloses the connecting region 209. The sealing device 210 comprises a sealing element 211, which comprises an elastomer, and a fixing device 212. Fig. 2 is a perspective sectional view of the connecting region 209 and the sealing device 210 surrounds the connecting region 209 rotationally symmetrically, the elements 211 and 212 of the sealing device 210 are shown to the left and right of the connecting region 209.

[0046] The sealing element 211 is pressed onto the connection region 209 by the fixing device 212, thereby enclosing at least leaky regions or potentially leaky regions of the connection region 209. The sealing element 211 is at least partially encapsulated from the environment by the fixing device 212. The potentially free regions of the sealing element 211 must therefore be suitable for use in a vacuum environment, and in particular in an EUV plasma environment. Therefore, the sealing element 211 consists, for example, of a fluororubber or perfluororubber. Likewise, the sealing element 211 can consist of nitrile rubber, ethylene-propylene-diene rubber, or a tetrafluoroethylene-hexafluoropropylene copolymer. The fixing device 212 can be designed as a clamp and made of stainless steel. The clamp preferably has an open thread according to the application, which makes it easier to clean.

[0047] In the following, the Fig. 3-5 show various embodiments of media-carrying pipe systems, comprising a metallic section, a section consisting of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K, a connecting region, and a sealing device at least partially surrounding the connecting region according to the present invention. The embodiments are part of an optical component for operation in a vacuum environment of EUV lithography, for example according to Fig. 2, which are not shown individually again for reasons of clarity.

[0048] Fig. 3a and Fig. 3b shows two embodiments 300, 307 of a media-carrying tube system of an optical component for operation in a vacuum environment with a sealing device 314, 315. A metallic tube section 302, 309 is connected, for example, welded, soldered, glued, or clamped, to a tube section 301, 308 consisting of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K via a connecting region 303, 310. The connecting region 303, 310 is at least partially enclosed by the externally applied sealing device 314, 315, wherein the sealing device 314, 315 comprises a sealing element 304, 311 and a fixing device 305, 312. The sealing element 304, 311 is fastened to the connecting area 303, 310 by the fixing device 305, 312.For the best possible sealing effect, the shape of the sealing element 304, 311 is adapted to the surroundings of the connecting area 303, 310. Regarding possible materials for the two connected sections 301, 302, 308, 309, the sealing element 304, 311 and the fixing device 305, 312, the specifications apply. Fig. 2 described examples analogously.

[0049] Characteristic of the embodiments 300, 307 according to the Fig. 3a and Fig. Figure 3b shows the symmetrical design, which is expressed by a mirror axis 306, 313 within the sealing devices 314, 315, parallel along the connecting areas 303 or 310. The advantages of a symmetrical design are improved ease of assembly and the most uniform possible compression of the sealing element 304, 311 relative to the connecting area 303, 310.

[0050] Fig. 4a and Fig. 4b shows two further embodiments 400, 406 of a media-carrying tube system of an optical component for operation in a vacuum environment with a sealing device 414, 415. A metallic section 402, 408 is connected, for example, welded, soldered, glued, or clamped, to a section consisting of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K 401, 407 via a connecting region 403, 409. The connecting region 403, 409 is at least partially enclosed by the externally applied sealing device 414, 415, wherein the sealing device 414, 415 comprises a sealing element 404, 410 and a fixing device 405, 411. The sealing element 404, 410 is fastened to the connecting area 403, 409 by the fixing device 405, 411.

[0051] Regarding possible materials of the two connected sections 401, 402, 407, 408, the sealing element 404, 410 and the fixing device 405, 411, the Fig. 2 described examples analogously.

[0052] Characteristic of the embodiments 400, 406 according to the Fig. 4a and Fig. 4b is an asymmetric design of the sealing device 414, 415, which is expressed by the absence of a mirror axis within the sealing devices 414, 415 parallel along the connecting areas 403 or 409. If an asymmetric design is selected due to the geometry of the sections to be connected, the sealing element 404, 410 can have a special marking to improve ease of assembly. For the best possible sealing effect, the shape of the sealing element 404, 410 for the asymmetric design is also adapted to the surroundings of the connecting area 403, 409. For better positioning and support of the sealing element 410 on the section 407 as well as the fixing device 411, this can, as in Fig. 4b, individually adapted webs 412, 413.

[0053] Fig. 5a and Fig. 5b shows two further embodiments 500, 508 of a media-carrying tube system of an optical component for operation in a vacuum environment with a sealing device 516, 517. A metallic section 502, 510 is connected via a connecting region 503, 511 to a section 501, 509 consisting of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K, for example, welded, soldered, glued, or clamped. These embodiments 500, 508 have a symmetrical design, which is expressed by a mirror axis 506, 514 within the sealing devices 516, 517 parallel along the connecting regions 503, 511. The connecting region 503, 511 is at least partially enclosed by the externally located sealing device 516, 517, wherein the sealing device 516, 517 comprises a sealing element 504, 512 and a fixing device 505, 513.The sealing element 504, 512 is fastened to the connecting area 503, 511 by the fixing device 505, 513.

[0054] In addition to the embodiments of the Fig. 3a, Fig. 3b, Fig. 4a, and Fig. 4b, the embodiments 500, 508 each have a shielding unit 507, 515. According to Fig. 5a, the shielding unit 507 surrounds the sealing element 504 and the fixing device 505, whereby the fixing device 505 acts directly to fix the sealing element 504 at the connecting area 503. Likewise, as in Fig. As shown in Figure 5b, the shielding unit 515 can be arranged between the sealing element 512 and the fixing device 513. In particular, if the shielding unit 515 is designed as a foil, a more stable fastening can be achieved by this component, since the fixing device 513 also acts as a fastening element for the shielding unit 515 in this case.

[0055] The shielding unit 507, 515 improves the usability of the sealing device 516, 517 during operation in a vacuum environment and / or an EUV plasma environment within the projection exposure system 100 by encapsulating the sealing element or the sealing element and the fixing device. This may be necessary in particular in areas of the projection exposure system 100 with very high cleanliness requirements and / or EUV plasma density. The shielding unit 507, 515 prevents or minimizes outgassing and any possible interaction with the EUV-induced plasma of the sealing device 516, 517. For this purpose, the shielding unit 507, 515 is made of aluminum, copper, or stainless steel, for example. The use of a shielding unit is also feasible for an asymmetric design.

[0056] For the best possible sealing effect, the shape of the sealing element 504, 512 is adapted to the surroundings of the connecting area 503, 511. Regarding possible materials of the two connected sections 501, 502, 509, 510, the sealing element 504, 512 and the fixing device 505, 513, the Fig. 2 described examples analogously.

[0057] Fig. 6a and Fig. 6b shows two method steps for the assembly of a sealing element 604 as a component of a sealing device 210 for a media-conducting pipe system 600 of an optical component. According to the invention, the media-conducting pipe system 600 comprises a metallic section 602 and a section made of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K 601, which are connected by a connecting region 603, for example, welded, soldered, glued, or clamped. Since the media-conducting pipe system 600 is designed for operation in a vacuum environment, and the connecting region 603 has a risk of becoming leaky during operation or during assembly in preparation for operation, the connecting region 603 of the media-conducting pipe system 600 should be additionally protected by a sealing device.

[0058] For this purpose, as in Fig. 6a, the sealing element 604, which typically consists of an elastomer, is guided over the first section 601 of the media-carrying pipe system 600 with the aid of an assembly cone 605. Advantageously, the pipe section with the smaller diameter is used first. The assembly cone 605 allows a continuous expansion of an inner diameter d1 of the sealing element 604 to an enlarged inner diameter d2. Upon reaching the enlarged inner diameter d2, the assembly cone is removed in the direction of the pipe section 601 with the smaller inner diameter. As shown in Fig. As shown in Figure 6b, the sealing element 604 thus clamped can be pulled over the first section 601, wherein the sealing element 604 is moved in the direction of the arrow to the connecting region 603. Here, the sealing element 604 can be fastened to the connecting region 603 with a fixing device and, if necessary, a shielding unit (both not shown).

[0059] Fig. 7 shows a method sequence of an embodiment of the inventive method for assembling a sealing device 210, 314, 315, 414, 415, 516, 517 of a media-carrying pipe system 300, 307, 400, 406, 500, 508, 600 for forming the inventive optical component 200. The method is described with reference to the illustrated media-carrying pipe systems 300, 307, 400, 406, 500, 508 of an optical component 200 and is applicable thereto.

[0060] In a first step S1, a mounting cone 605 is provided at an open end of a first section 601. The mounting cone 605 enables the bridging of a diameter difference between a sealing element 211, 304, 311, 404, 410, 504, 512, 604 and the first section of the media-carrying pipe system 300, 307, 400, 406, 500, 508, 600. The mounting cone 605 is advantageously placed on the section with the smaller diameter of the two sections, so that the diameter difference to be bridged is as small as possible.

[0061] In a second step S2, a sealing element 211, 304, 311, 404, 410, 504, 512, 604 is provided. The sealing element 211, 304, 311, 404, 410, 504, 512, 604 comprises an elastomer, for example, a fluororubber or perfluororubber. Likewise, the sealing element 211, 304, 311, 404, 410, 504, 512, 604 can comprise nitrile rubber, ethylene-propylene-diene rubber, or a tetrafluoroethylene-hexafluoropropylene copolymer.

[0062] In a third step S3, the sealing element 211, 304, 311, 404, 410, 504, 512, 604 is placed on the mounting cone 605 at the open end of the first section 601.

[0063] In a fourth step S4, the sealing element 211, 304, 311, 404, 410, 504, 512, 604 is pulled over the first section 601 and brought to a connecting region 209, 303, 310, 403, 409, 503, 511, 603 in order to enclose it. Since the elastic sealing element 211, 304, 311, 404, 410, 504, 512, 604 is expanded for assembly by means of the assembly cone 605, starting from an inner diameter d1 to an inner diameter d2, the sealing element 211, 304, 311, 404, 410, 504, 512, 604 nestles against the surrounding connection area (209, 303, 310, 403, 409, 503, 511, 603).

[0064] In a fifth step S5, a fixing device 212, 305, 312, 405, 411, 505, 513 is provided. The fixing device 212, 305, 312, 405, 411, 505, 513 can comprise a stainless steel clamp. Preferably, the clamp has an open thread according to the application, which makes it easier to clean.

[0065] In a sixth step S6, the fixing device 212, 305, 312, 405, 411, 505, 513 is fastened to the sealing element 211, 304, 311, 404, 410, 504, 512, 604 such that the fixing device 212, 305, 312, 405, 411, 505, 513 at least partially encloses and presses the sealing element 211, 304, 311, 404, 410, 504, 512, 604, whereby the sealing device 210, 314, 315, 414, 415, 516, 517 is obtained.

[0066] Preferably, in a seventh step S7, a shielding unit 507 is provided. The shielding unit 507 is made of aluminum, copper, or stainless steel, for example.

[0067] Preferably, in an eighth step S8, the shielding unit 507 is attached to the sealing device 516 such that the shielding unit 507 at least partially, in particular completely, encloses the sealing device 516. The shielding unit 507 improves the usability of the sealing device 516 during operation in a vacuum environment and / or an EUV plasma environment within a projection exposure system 100 by at least partially encapsulating the sealing element 504 and the fixing device 505. This prevents or minimizes outgassing and possible interaction with the EUV-induced plasma of the sealing device 516.

[0068] In an alternative embodiment of the method according to the invention, a shielding unit 515 is provided in a step S4.1, after step S4, and fastened to a sealing element 512 in a step S4.2. In the subsequent steps S5 and S6, the fixing device 513 is provided and fastened to the shielding unit 515 and the underlying sealing element 512. In particular, if the shielding unit 515 is designed as a film, a more stable fastening can be achieved by this embodiment of the method, since the fixing device 513 in this case also has a fastening effect for the shielding unit 515.

[0069] Fig.8 shows an embodiment of a clamp 800 as a fixing element with an open thread 806 for a variant of the component according to the invention. The clamp 800 is made of stainless steel, for example, and comprises an approximately circular base body 801, which further comprises a positioning aid 802 for improved fixing of a sealing element (not shown). Furthermore, the clamp 800 comprises two connecting regions 803, 804, which are attached to the upper region of the base body 801. A gap 805 is formed between the two connecting regions 803, 804. Due to the gap 805, the thread 806 arranged in the first connecting region 803 is open in the disassembled state and thus freely accessible, for example, for cleaning. To fix the clamp 800 to a sealing element, a screw 807 is guided through an elongated hole 808 of the second connection area until the screw 807 engages in the thread 806 by a rotating movement.As a result, the gap 805 decreases as the rotational movement continues, and the clamp 800 can thereby fix a sealing element to a connection area (both not shown). List of reference symbols 100 projection exposure system 101 Lighting system 102 Radiation source 103 Lighting optics 104 Object field 105 Object level 106 reticles 107 reticle holders 108 Projection optics 109 image field 110 Image plane 111 wafers 112 wafer holders 113 EUV radiation 114 Intermediate focal plane 115 field facet mirrors 116 Pupillary facet mirror 117 - 119 additional mirrors of the lighting optics 120 - 125 additional optical elements of the projection optics 126 collector mirrors 200 optical components 201 Mirror substrate 202 reflective surface 203 Channel 204 entrance piece 205 starting piece 206 metallic pipe section 207 metallic pipe section 208 Connection area 209 Connection area 210 Sealing device 211 Sealing element 212 Fixing device 300 media-carrying pipe system of an optical component 301 Pipe section made of silicon-containing substrate material 302 metallic pipe section 303 Connection area 304 sealing element 305 Fixing device 306 Mirror axis 307 Media-carrying pipe system of an optical component 308 Pipe section made of silicon-containing substrate material 309 metallic pipe section 310 connection area 311 sealing element 312 Fixing device 313 Mirror axis 314 Sealing device 315 Sealing device 400 media-carrying pipe system of an optical component 401 Pipe section made of silicon-containing substrate material 402 metallic pipe section 403 Connection area 404 Sealing element 405 Fixing device 406 Media-carrying pipe system of an optical component 407 Pipe section made of silicon-containing substrate material 408 metallic pipe section 409 Connection area 410 sealing element 411 Fixing device 412 jetty 413 jetty 414 Sealing device 415 Sealing device 500 media-carrying pipe system of an optical component 501 Pipe section made of silicon-containing substrate material 502 metallic pipe section 503 connection area 504 sealing element 505 Fixing device 506 Mirror axis 507 Shielding unit 508 Media-carrying pipe system of an optical component 509 Pipe section made of silicon-containing substrate material 510 metallic pipe section 511 connection area 512 sealing element 513 Fixing device 514 Mirror axis 515 Shielding unit 516 Sealing device 517 Sealing device 600 media-carrying pipe system of an optical component 601 Pipe section made of silicon-containing substrate material 602 metallic pipe section 603 connection area 604 sealing element 605 mounting cone S1 first process step S2 second process step S3 third process step S4 fourth process step S5 fifth process step S6 sixth process step S7 seventh process step S8 eighth process step S4.1 alternative process step S4.2 alternative process step 800 bells 801 basic body 802 Positioning aid 803 first connection area 804 second connection area 805 gap 806 thread 807 screw 808 slot QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 102017221388A1 [0006, 0043] DE 102022203254B3

[0007] DE 102020208496A1

[0007] DE 102020208200A1

[0007] WO 15050428A1

[0011] US 9411241B2

[0038] US 2016 / 0327868A1

[0041] DE 102018207277A1

[0041]

Claims

[1] Optical component (200) for EUV lithography, comprising a media-carrying tube system (300, 307, 400, 406, 500, 508) for operation in a vacuum environment, wherein the media-carrying tube system (300, 307, 400, 406, 500, 508) has at least one connecting region (209, 303, 310, 403, 409, 503, 511) between a metallic section (207, 302, 309, 402, 408, 502, 510) and a section consisting of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K (205, 301, 308, 401, 407, 501, 509), characterized bythat the connecting region (209, 303, 310, 403, 409, 503, 511) is at least partially enclosed by an externally applied sealing device (210, 314, 315, 414, 415, 516, 517), wherein the sealing device (210, 314, 315, 414, 415, 516, 517) comprises a sealing element (211, 304, 311, 404, 410, 504, 512) and a sealing element (211, 304, 311, 404, 410, 504, 512) on the connecting region (209, 303, 310, 403, 409, 503, 511) fastening device (212, 305, 3012, 405, 411, 505, 513) and wherein the sealing element (211, 304, 311, 404, 410, 504, 512) comprises an elastomer. [2] Optical component according to claim 1, characterized by that the sealing device (516, 517) further comprises a shielding unit (507, 515). [3] Optical component according to claim 1 or 2, characterized bythat the sealing device (210, 314, 315, 516, 517) has a mirror axis (306, 313, 506, 514) running parallel to the connecting region (209, 303, 310, 503, 511). [4] Optical component according to one of the preceding claims, characterized by that the media-carrying pipe system (300, 307, 400, 406, 500, 508) is a water-carrying pipe system for tempering the optical component. [5] Optical component according to claims 1-3, characterized by that the media-carrying pipe system (300, 307, 400, 406, 500, 508) is a gas-carrying pipe system. [6] Optical component according to one of the preceding claims, characterized by that the connecting region (209, 303, 310, 403, 409, 503, 511) has a welded, soldered, glued or clamped interface. [7] Optical component according to one of the preceding claims, characterized bythat the metallic section (207, 302, 309, 402, 408, 502, 510) comprises stainless steel, aluminum, nickel or copper. [8] Optical component according to one of the preceding claims, characterized by that the section (205, 301, 308, 401, 407, 501, 509) consisting of a silicon-containing substrate material comprises quartz glass, titanium-doped quartz glass or SiSiC. [9] Optical component according to one of the preceding claims, characterized by that the sealing element (211, 304, 311, 404, 410, 504, 512) comprises a fluorine-containing polymer. [10] Optical component according to one of the preceding claims, characterized by that the fixing device (212, 305, 312, 405, 411, 505, 513) comprises a clamp (800) made of stainless steel. [11] Optical component according to claim 10, characterized by that the clamp (800) has an open thread (806) for screwing. [12] Projection exposure system (100), in particular for EUV lithography, comprising an optical component (200) according to one of the preceding claims. [13] Method for assembling a sealing device (210, 314, 315, 414, 415, 516, 517) for a connecting region (209, 303, 310, 403, 409, 503, 511, 603) between a metallic section (207, 302, 309, 402, 408, 502, 510, 602) and a section consisting of a silicon-containing substrate material with a coefficient of linear expansion of less than 3 ppm / K (205, 301, 308, 401, 407, 501, 509, 601) of a media-carrying pipe system (300, 307, 400, 406, 500, 508, 600) of an optical component (200) for a vacuum environment comprising the following steps, - providing a mounting cone (605) at an open end of a first section (601) (S1), - Providing a sealing element (211, 304, 311, 404, 410, 504, 512, 604) (S2), - placing the sealing element (211, 304, 311, 404, 410, 504, 512, 604) on the mounting cone (605) at the open end of the first section (601) (S3), - covering the sealing element (211, 304, 311, 404, 410, 504, 512, 604) over the first section (601), wherein the sealing element (211, 304, 311, 404, 410, 504, 512, 604) is brought to the connecting region (603) and encloses it (S4), - providing a fixing device (212, 305, 3012, 405, 411, 505, 513) (S5), - Fastening the fixing device (212, 305, 3012, 405, 411, 505, 513) to the sealing element (211, 304, 311, 404, 410, 504, 512, 604) in such a way that the fixing device (212, 305, 3012, 405, 411, 505, 513) at least partially encloses and presses the sealing element (211, 304, 311, 404, 410, 504, 512, 604), whereby the sealing device (210, 314, 315, 414, 415, 516, 517) is obtained (S6). [14] The method of claim 13 further comprising, - Providing a shielding unit (507) (S7), - Fastening the shielding unit (507) to the sealing device (516) such that the shielding unit (507) at least partially, in particular completely, encloses the sealing device (516) (S8). [15] Method according to claim 13, characterized by that a shielding unit (515) is provided after the sealing element (512) has been covered (S4.1) and is fastened to the sealing element (512) in such a way that it at least partially, in particular completely, encloses the sealing element (512) (S4.2).

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