Device for use in a radiation source

Abstract

A container arranged to receive waste from a laser-generated plasma radiation source is provided. The container comprises: a first portion defining a chamber; and a second portion defining at least partially an inlet to the chamber. In use, the waste enters the chamber through the inlet. The second portion is formed of a material including a ceramic material. The container may be particularly useful in a radiation source used in a lithography system.

Description

Technology Field

[0001] This application claims priority to EP application No. 19203471.8 filed on October 16, 2019, the entirety of which is incorporated herein by reference.

[0002] The present invention relates to a radiation source. In particular, the present invention relates to an apparatus suitable for transporting and / or receiving waste from a radiation source, such as tin. Background Technology

[0003] A lithography device is a machine configured to apply a desired pattern onto a substrate. A lithography device can be used, for example, in the manufacture of integrated circuits (ICs). A lithography device can project a pattern onto a layer of radiation-sensitive material (resist) provided on a substrate, for example, from a patterning device (e.g., a mask).

[0004] To project a pattern onto a substrate, a lithography device may use electromagnetic radiation. The wavelength of such radiation determines the minimum size of the feature that can be formed on the substrate. A lithography device using extreme ultraviolet (EUV) radiation with a wavelength in the range of 4 nm to 20 nm, for example 6.7 nm or 13.5 nm, is used to form smaller features on a substrate than a lithography device using radiation with a wavelength of, for example, 193 nm.

[0005] EUV radiation can be generated using a laser-generated plasma (LPP) radiation source. An LPP radiation source can use a fuel such as liquid tin. After generating EUV radiation, tin may constitute waste from the radiation source. A discharge system may be used to remove waste (e.g., liquid tin) from the radiation source. To facilitate the removal of such waste, a part of the discharge system may be maintained at a temperature above the melting point of the waste so that the waste can flow.

[0006] However, particularly if the components of the discharge system are not maintained above the melting point of the waste, the waste may accumulate in one or more components of the discharge system. This may result in a reduction in flow rate and / or blockage within the discharge system. Additionally, tin can corrode the components of the discharge system, thereby shortening their service life. The problem to be solved

[0007] It may be desirable to overcome the aforementioned issues regarding waste from radiation sources (such as annotations). Accordingly, embodiments of the present invention relate to a new device suitable for transporting and receiving waste from radiation sources. means of solving the problem

[0008] According to a first aspect of the present invention, a container arranged to receive waste from a laser-generated plasma radiation source is provided. The container may include a first portion. The first portion may define a chamber. The container may include a second portion. The second portion may at least partially define an inlet to the chamber. In use, the waste may enter the chamber through the inlet. The second portion may be formed of a material including a ceramic material.

[0009] A second part is formed of a material including a ceramic material that at least partially defines an inlet to a chamber. In particular, one or more surfaces of the second part defining the inlet to the chamber may be formed of a material including a ceramic material. In some embodiments, the second part may be formed of such a ceramic material. Alternatively, the second part may be formed of another material that can be coated with such a ceramic material.

[0010] The waste from the above radiation source may contain tin.

[0011] The first part may be referred to as the main body. The second part may be referred to as the collar. The inlet of the chamber may be limited to an opening.

[0012] A laser-generated plasma (LPP) radiation source can generate radiation by providing energy through a laser beam to droplets of liquid fuel, such as liquid tin. Such liquid fuel may constitute waste from the radiation source. That is, said waste may include liquid tin. It may be desirable to remove such waste from said radiation source. A discharge system may be provided at said radiation source. All waste within said radiation source may be discharged into a container through said discharge system. said container may also be referred to as a bucket. said container may be arranged to receive and store the waste. In particular, said waste may be received into said chamber through said inlet and stored within said chamber.

[0013] The above-described container advantageously comprises a first portion and a second portion. In particular, the first portion (which may constitute the body of the container) may be formed of a first material, and the second portion (which may constitute the collar of the container) may be formed of a second different material. The material of the first portion and the material of the second portion may be selected to have different and advantageous properties. For example, the material of the first portion may advantageously be suitable for storing waste from the radiation source. The material of the second portion may advantageously be suitable for non-stickiness and / or non-wettingness to the waste.

[0014] The ceramic material on which the second portion is formed may be substantially non-wetting with respect to the waste. When waste comes into contact with the second portion, the surface of the second portion may not wet. Additionally, the second portion may be substantially non-stick with respect to the waste. The non-stick properties of the ceramic material may facilitate the removal of the waste from the surface of the second portion. Therefore, even if the second portion is at a temperature lower than the melting point of the waste, there is little chance that any waste will remain on the surface of the second portion. Advantageously, this can prevent the accumulation of the waste around the chamber inlet. This can prevent the discharge system, which constitutes part of the vessel, from becoming clogged. This is advantageous because any clogging of the discharge system can result in a substantial reduction in throughput (e.g., of a radiation source and / or lithography device).

[0015] In particular, earlier design vessels intended for use in radiation source exhaust systems may not include a second part formed of ceramic material. Such earlier designs are prone to clogging due to waste accumulation. In such earlier designs, waste can wet the surface near the opening of the vessel. In such earlier designs, waste can adhere to the surface near the opening of the vessel. Consequently, over time, increasingly more waste may accumulate near the opening of the vessel. This can reduce the efficiency of transferring waste into such earlier design vessels. This can eventually lead to clogging of the exhaust system using such earlier design vessels.

[0016] A container of a new design according to the first aspect of the present invention substantially mitigates (and can even eliminate) the risk of such blockage occurring. Accordingly, a container of a new design according to the first aspect of the present invention provides significant advantages over known containers.

[0017] Hydrogen gas may be supplied within the radiation source. A mechanism for supplying a flow of hydrogen gas within the radiation source may be provided. By supplying a flow of hydrogen gas across the surfaces of the components within the radiation source, it may help prevent waste from interacting with the surfaces and / or prevent waste from accumulating on the surfaces.

[0018] Most metal-containing materials may generally be non-wetting to waste under normal atmospheric conditions. This non-wetting characteristic may be due to an oxide layer formed on the surface of such materials. However, such an oxide layer can be removed in a hydrogen-containing environment. In particular, in an environment where hydrogen radicals are present, the oxide layer can be chemically reduced. This can lead to increased wetting of the waste. Therefore, it may be particularly difficult to prevent the accumulation of waste on the surface of the second part due to the presence of hydrogen gas and / or hydrogen radicals.

[0019] A particular advantage of the container according to the first embodiment of the present invention is that, even in the presence of hydrogen, the ceramic material is generally non-wetting with respect to waste and generally does not adhere to the waste. Accordingly, a second part formed of such a ceramic material provides the aforementioned advantage even in particularly challenging environments created in the presence of hydrogen.

[0020] The first part may be formed from a material containing molybdenum. The first part may be formed from a material containing more than 90% molybdenum, for example, more than 95% molybdenum. For example, the first part may be formed from a material containing a titanium-zirconium-molybdenum alloy. Such a titanium-zirconium-molybdenum alloy may contain 99.4% molybdenum, 0.5% titanium, and 0.08% zirconium.

[0021] When formed from a material containing molybdenum (e.g., a titanium-zirconium-molybdenum alloy), corrosion of the first part by the waste may be negligible or may not occur at all. For example, corrosion of the first part by liquid tin may be negligible or may not occur at all. In particular, at a temperature at which the container can be maintained, corrosion of the first part may be negligible or may not occur at all. This is particularly advantageous compared to known containers for storing waste from a radiation source (e.g., liquid tin) that can be formed from stainless steel. The waste may react with stainless steel. Stainless steel may be corroded by the waste. This may lead to failure of such a container. Impurities, welding defects, and / or thermal stress in the stainless steel may exacerbate such problems. Thermal gradients may exacerbate such problems.

[0022] TZM can substantially be resistant to hydrogen embrittlement. This is particularly advantageous due to the possibility that hydrogen gas and / or hydrogen radicals may be present near the first portion.

[0023] The ceramic material may contain boron and / or fluorine. Advantageously, the ceramic material containing boron or fluorine has been found to be particularly non-wetting and non-sticky to tin, even in a reducing environment in the presence of hydrogen gas and / or hydrogen radicals.

[0024] The ceramic material may include silicon oxide; magnesium oxide; aluminum oxide; potassium oxide; boron oxide; and fluorine.

[0025] Such materials may include materials marketed as MACOR™ by Corning Inc., established in the United States. Such materials may enable the second part to achieve the important advantages described above by carrying out the first aspect of the present invention. MACOR™ may be non-sticky, particularly with respect to waste (particularly, liquid tin). MACOR™ may be non-wetting, particularly with respect to waste (particularly, liquid tin). MACOR™ may generally be non-wetting and non-sticky with respect to waste, even in the presence of hydrogen. In particular, such materials contain boron and fluorine.

[0026] The ceramic material may include metal nitrides. Advantageously, metal nitrides (particularly boron nitride and aluminum nitride) have been found to be particularly non-wetting and non-sticky to tin, even in reducing environments where hydrogen gas and / or hydrogen radicals are present. Such metal nitrides may be more suitable than, for example, metal oxides.

[0027] The above ceramic material may include boron nitride.

[0028] Such a material can enable the second part to carry out the first aspect of the present invention to achieve the important advantages described above. Boron nitride may be non-sticky, particularly to waste (particularly, liquid tin). Boron nitride may be non-wetting, particularly to waste (particularly, liquid tin). Boron nitride may be generally non-wetting and also generally non-sticky to waste, even in the presence of hydrogen.

[0029] Boron nitride can be pyrolytic boron nitride.

[0030] That is, the ceramic material may comprise pyrolytic boron nitride. Such a material may enable the second part to achieve the important advantages described above by carrying out the first aspect of the present invention. Pyrolytic boron nitride may be non-sticky, particularly to waste (particularly, liquid tin). Pyrolytic boron nitride may be non-wetting, particularly to waste (particularly, liquid tin). Pyrolytic boron nitride may be generally non-wetting and also generally non-sticky to waste, even in the presence of hydrogen.

[0031] The above ceramic material may include aluminum nitride.

[0032] The ceramic material may include boron nitride and aluminum nitride. Such materials may include materials commercially available as SHAPAL™, SHAPAL™-M and / or SHAPAL™ Hi-M Soft. Such materials may enable the second part to achieve the important advantages described above by carrying out the first aspect of the invention. Boron nitride and aluminum nitride may be non-sticky, particularly to waste (particularly liquid tin). Boron nitride and aluminum nitride may be non-wetting, particularly to waste (particularly liquid tin). Boron nitride and aluminum nitride may be generally non-wetting and also generally non-sticky to waste, even in the presence of hydrogen.

[0033] According to a second aspect of the present invention, a laser-generated plasma radiation source comprising a vessel according to the first aspect of the present invention is provided.

[0034] According to a third aspect of the present invention, a laser-generated plasma radiation source is provided. The laser-generated plasma radiation source may include a component for use in an exhaust system of the radiation source. The component may define a chamber arranged to receive waste from the radiation source. The component may be formed of a material comprising molybdenum.

[0035] The above component may be formed from a material containing more than 90% molybdenum, for example, more than 95% molybdenum. For example, the above component may be formed from a material containing a titanium-zirconium-molybdenum alloy. Such a titanium-zirconium-molybdenum alloy may contain 99.4% molybdenum, 0.5% titanium, and 0.08% zirconium.

[0036] The above discharge system may be used to facilitate the removal of waste from the radiation source. An LPP radiation source according to a third aspect of the present invention is advantageous because, when formed from a material containing molybdenum (e.g., TZM), corrosion of the component by the waste can be neglected or may not occur at all. An LPP radiation source according to a third aspect of the present invention is particularly advantageous compared to an LPP radiation source comprising a component formed of stainless steel, for example. For example, waste from the radiation source can react with a component formed of stainless steel. Stainless steel can be corroded by the waste. This can lead to failure of such a component. Impurities, welding defects, thermal gradients, and / or thermal stress in the stainless steel can exacerbate such problems.

[0037] TZM can be substantially resistant to hydrogen embrittlement. This is particularly advantageous due to the possibility that hydrogen gas and / or hydrogen radicals may be present near components within the radiation source.

[0038] The above component may be a container. Advantageously, corrosion of the container by waste may be negligible or may not occur at all.

[0039] According to a fourth aspect of the present invention, a laser-generated plasma radiation source is provided that includes a component for use in an exhaust system of the radiation source, wherein the component comprises a ceramic material containing boron and / or fluorine.

[0040] A component of a radiation source according to a fourth aspect of the present invention comprises a ceramic material. It should be understood that this is intended to include embodiments in which the entire component is formed of such a ceramic material, or alternatively, embodiments in which the component is formed of another material that can be coated with such a ceramic material.

[0041] An LPP radiation source according to a fourth aspect of the present invention is advantageous because the ceramic material may be substantially non-wetting with respect to waste. Advantageously, ceramic materials containing boron or fluorine have been found to be non-wetting and non-stick, particularly with respect to tin, even in a reducing environment in the presence of hydrogen gas and / or hydrogen radicals. When waste comes into contact with the component, the surface of the component may not get wet. Additionally, the ceramic material may be substantially non-stick with respect to waste. The non-stick properties of the ceramic material allow for easy removal of waste from the surface of the component. Advantageously, this can prevent the accumulation of waste on the component. This can prevent the discharge system from becoming clogged. This is advantageous because any clogging of the discharge system can result in a substantial reduction in throughput (e.g., of the radiation source and / or lithography device).

[0042] The ceramic material may include: silicon oxide; magnesium oxide; aluminum oxide; potassium oxide; boron oxide; and fluorine. The discharge system may be used to facilitate the removal of waste from the radiation source. The ceramic material may include a material marketed as MACOR™ by Corning Inc., established in the United States. Additionally, or alternatively, the ceramic material may include boron nitride.

[0043] According to a fifth aspect of the present invention, a laser-generated plasma radiation source is provided, comprising a component for use in an exhaust system of the radiation source, wherein the component comprises a ceramic material comprising a metal nitride. The ceramic material may comprise boron nitride and / or aluminum nitride.

[0044] A component of a radiation source according to a fifth aspect of the present invention comprises a ceramic material. It should be understood that this is intended to include embodiments in which the entire component is formed of such a ceramic material, or alternatively, embodiments in which the component is formed of another material that can be coated with such a ceramic material.

[0045] The above exhaust system may be used to facilitate the removal of waste from the radiation source. The LPP radiation source according to the fifth aspect of the present invention is advantageous in that the ceramic material may be substantially non-wetting with respect to waste. Advantageously, metal nitrides (particularly boron nitride and aluminum nitride) have been found to be particularly non-wetting and non-sticky with respect to tin, even in reducing environments where hydrogen gas and / or hydrogen radicals are present. Such metal nitrides may be more suitable, for example, than metal oxides. When waste comes into contact with the component, the surface of the component may not be wet. Additionally, the ceramic material may be substantially non-sticky with respect to waste. The non-stick properties of the ceramic material allow for the easy removal of waste from the surface of the component. Advantageously, this can prevent the accumulation of waste on the component. This can prevent the exhaust system from becoming clogged. This is advantageous because any blockage of the above-mentioned exhaust system can result in a substantial reduction in throughput (e.g., of a radiation source and / or lithography device).

[0046] The ceramic material may include boron nitride and / or aluminum nitride. The boron nitride may include pyrolytic boron nitride.

[0047] The ceramic material may include materials commercially available as SHAPAL™, SHAPAL™-M, and / or SHAPAL™ Hi-M Soft.

[0048] A radiation source according to a second, third, fourth, or fifth aspect of the present invention may further include a mechanism for providing hydrogen. Hydrogen may be provided to one or more surfaces within the radiation source.

[0049] By providing a flow of hydrogen gas across one or more surfaces within the radiation source, it may help prevent waste from the radiation source from interacting with the surfaces and / or accumulating on the surfaces.

[0050] Most metal-containing materials may generally be non-wetting with respect to waste under normal atmospheric conditions. This non-wetting characteristic may be due to an oxide layer formed on the surface of such materials. However, such an oxide layer can be removed in a hydrogen-containing environment. In particular, in an environment where hydrogen radicals are present, the oxide layer can be chemically reduced. This may result in increased wettability with respect to waste. Therefore, it may be particularly difficult to prevent the accumulation of waste on the surface of the second part due to the presence of hydrogen gas and / or hydrogen radicals.

[0051] A particular advantage of forming components with materials provided in the second, third, fourth, or fifth embodiment of the present invention is that such materials may be generally non-wetting and generally non-sticky to waste, even in the presence of hydrogen, and / or may generally be resistant to corrosion caused by waste such as tin. Accordingly, LPP radiation sources according to the second, third, fourth, or fifth embodiment of the present invention provide significant advantages even in particularly challenging environments created in the presence of hydrogen.

[0052] A component of a radiation source according to a third, fourth, or fifth aspect of the present invention may at least partially limit an inlet to a chamber. The chamber may be arranged to receive waste from the radiation source. The component may correspond to a "second part" according to a first aspect of the present invention. The component may be referred to as a collar. The collar may be substantially non-wetting with respect to waste. When waste comes into contact with the collar, the surface of the collar may not be wet. Additionally, the collar may be non-sticky with respect to waste. The non-stick properties of the ceramic material allow for easy removal of waste from the surface of the collar. Advantageously, this prevents the accumulation of waste on the collar. This prevents the discharge system from becoming clogged. This is advantageous because any clogging of the discharge system can result in a substantial reduction in throughput (e.g., of the radiation source and / or lithography device).

[0053] A component of a radiation source according to a third, fourth, or fifth aspect of the present invention may include a pipe. The pipe may be configured to transport waste from the radiation source.

[0054] The pipe may be substantially non-wetting with respect to waste. When waste comes into contact with the pipe, the surface of the pipe may not get wet. Additionally, the pipe may be substantially non-sticky with respect to waste. The non-stick properties of the ceramic material allow for easy removal of waste from the surface of the pipe. Advantageously, this can prevent the accumulation of waste on the pipe. This can prevent the discharge system from becoming clogged. This is advantageous because any blockage of the discharge system can result in a substantial reduction in throughput (e.g., of a radiation source and / or lithography device).

[0055] Waste from a radiation source according to the second, third, fourth, or fifth embodiment of the present invention may contain tin. Brief explanation of the drawing

[0056] Now, embodiments of the present invention will be described merely as examples with reference to the accompanying schematic drawings, where: FIG. 1 schematically illustrates a side view of a lithography system including a lithography device and a radiation source. Figure 2 shows a three-dimensional rendering of a container for use in a radiation source. FIG. 3 schematically illustrates a side view of the container shown in FIG. 2. FIG. 4 illustrates a process in which the containers of FIG. 2 and FIG. 3 can be inserted into the discharge system of a radiation source. Specific details for implementing the invention

[0057] FIG. 1 illustrates a lithography system comprising a radiation source (SO) and a lithography device (LA). The radiation source (SO) is configured to generate an extreme ultraviolet (EUV) radiation beam (B) and also to supply the EUV radiation beam (B) to the lithography device (LA). The lithography device (LA) includes an illumination system (IL), a support structure (MT) configured to support a patterning device (MA) (e.g., a mask), a projection system (PS), and a substrate table (WT) configured to support a substrate (W).

[0058] The illumination system (IL) is configured to regulate the EUV radiation beam (B) before the EUV radiation beam (B) is incident on the patterning device (MA). Accordingly, the illumination system (IL) may include a facetted field mirror device (10) and a facetted pupil mirror device (11). The facetted field mirror device (10) and the facetted pupil mirror device (11) together provide an EUV radiation beam (B) having a desired cross-sectional shape and a desired intensity distribution. The illumination system (IL) may include other mirrors or devices in addition to or instead of the facetted field mirror device (10) and the facetted pupil mirror device (11).

[0059] After being adjusted in this way, the EUV radiation beam (B) interacts with the patterning device (MA). As a result of this interaction, a patterned EUV radiation beam (B') is generated. The projection system (PS) is configured to project the patterned EUV radiation beam (B') onto the substrate (W). To this end, the projection system (PS) may include a plurality of mirrors (13, 14) configured to project the patterned EUV radiation beam (B') onto the substrate (W) held by the substrate table (WT). The projection system (PS) may apply a reduction factor to the patterned EUV radiation beam (B') and thus form an image having features smaller than the corresponding features on the patterning device (MA). For example, a reduction factor of 4 or 8 may be applied. Although the projection system (PS) is depicted in FIG. 1 as having only two mirrors (13, 14), the projection system (PS) may include a number of different mirrors (e.g., six or eight mirrors).

[0060] A small amount of gas at a relative vacuum, that is, at a pressure much lower than atmospheric pressure, may be supplied to the radiation source (SO), the illumination system (IL), and / or the projection system (PS).

[0061] The radiation source (SO) illustrated in FIG. 1 is a type that may be referred to, for example, as a laser-generated plasma (LPP) source. A laser system (1), which may include, for example, a carbon dioxide (CO2) laser, is arranged to deposit energy into a fuel, such as tin (Sn), provided, for example, from a fuel emitter (3), via a laser beam (2). Any suitable fuel may be used, although tin will be mentioned in the following description. The fuel may be, for example, in liquid form, or may be, for example, a metal or an alloy. The fuel emitter (3) may include a nozzle configured to direct the tin, for example, in the form of a droplet, along a trajectory toward a plasma-forming region (4). The laser beam (2) is incident on the tin in the plasma-forming region (4). When laser energy is deposited into the tin, a tin plasma (7) is generated in the plasma-forming region (4). Radiation, including EUV radiation, is emitted from the plasma (7) during the de-excitation and recombination of ions and electrons in the plasma.

[0062] The laser system (1) may be spatially separated from the radiation source (SO). In this case, the laser beam (2) may be passed from the laser system (1) to the radiation source (SO) with the help of a beam delivery system (not shown) including, for example, suitable directional mirrors and / or a beam expander and / or other optical devices. The laser system (1), the radiation source (SO), and the beam delivery system may be considered together as a radiation system.

[0063] EUV radiation from the above plasma is collected and focused by a collector (5). The collector (5) includes, for example, an approximate vertical incident radiation collector (5) (sometimes more generally referred to as a vertical incident radiation collector). The collector (5) may have a multilayer mirror structure arranged to reflect EUV radiation (e.g., EUV radiation having a desired wavelength such as 13.5 nm). The collector (5) may have an elliptical configuration having two focal points. The first focal point may be located in the plasma forming region (4), and the second focal point may be located in the intermediate focal point position (6) discussed below.

[0064] The radiation reflected by the collector (5) forms the EUV radiation beam (B). The EUV radiation beam (B) is focused at an intermediate focal position (6) to form an image at the intermediate focal position (6) of the plasma present in the plasma forming region (4). The image at the intermediate focal position (6) acts as a virtual radiation source for the illumination system (IL). The radiation source (SO) is arranged so that the intermediate focal position (6) is located at or near the opening (8) within the sealed structure (9) of the radiation source (SO).

[0065] The process of converting tin droplets into tin plasma (7) is a high-energy process. Tin that is not converted into tin plasma (7) may be emitted from the plasma forming region (4) as a result of interaction with the laser beam (2). Tin that is not converted into tin plasma (7) may come into contact with the inner walls of the sealed structure (9) of the radiation source (SO) and / or other components within the radiation source (SO). Tin plasma (7) may also diffuse from the plasma forming region (4) (e.g., as a result of interaction with the laser beam (2). As electrons and ions of the tin plasma (7) recombine (thereby generating radiation including EUV radiation), tin atoms are formed. Such tin atoms may come into contact with the inner walls of the sealed structure (9) of the radiation source (SO) and / or other components within the radiation source (SO).

[0066] As described above, a small amount of gas may be supplied to the radiation source (SO) at a pressure much lower than atmospheric pressure. Hydrogen gas may be supplied into the radiation source (SO). A mechanism for providing a flow of hydrogen gas into the radiation source (SO) may be provided. By providing a flow of hydrogen gas across the surfaces of the components within the radiation source (SO), it may help prevent tin from interacting with the surfaces and / or accumulating on the surfaces.

[0067] The radiation source (SO) may be provided with a discharge system. Any tin within the sealed structure (9) may be discharged into a container (20) through the discharge system. The container (20) may also be referred to as a bucket. In particular, surfaces within the sealed structure (9) may be configured to facilitate the discharge of tin into the container (20). The container (20) may form part of the discharge system of the radiation source (SO). A pipe (30) may form part of the discharge system of the radiation source (SO). The pipe (30) may be used to transport tin into the container (20). Tin may be discharged from within the sealed structure (9) into the container (20) through the pipe (30). The discharge system may include one or more pipes.

[0068] It may be preferable that the tin discharged into the container (20) be in a liquid form. This may be preferable because the liquid tin can be collected at one end of the container (20) after being delivered to the container (20) (determined by gravity). The container (20) may be provided with a heating device. The heating device may heat the container (20) to an appropriate operating temperature. The appropriate operating temperature of the container (20) may be higher than the melting point of tin. It may be recognized that the temperature of the radiation source (SO) (particularly within the sealed structure (9)) may be significantly higher than the operating temperature of the container (20).

[0069] In some embodiments, the vessel (20) may be located within the radiation source (SO) and / or may be considered to be part of the radiation source. In other embodiments, the vessel (20) may be located at least partially outside the radiation source (SO) and / or may be considered not to form at least partially part of the radiation source (SO). In embodiments where the vessel (20) is located outside the vessel of the radiation source (SO), there may be slight differences from embodiments where the vessel is located inside the vessel of the radiation source (SO), but the overall concept may remain the same.

[0070] Although FIG. 1 shows the radiation source (SO) as a laser-generated plasma (LPP) source, any suitable source, such as a discharge-generated plasma (DPP) source (which may also generate waste such as tin), can also be used to generate EUV radiation.

[0071] FIG. 2 illustrates a three-dimensional rendering of a container (20) according to an embodiment of the present invention.

[0072] The above-mentioned container (20) comprises: a main body (21); and a collar (25). The main body (21) may be referred to as a first part. The collar (25) may be referred to as a second part.

[0073] The above container (20) also includes: a plurality of connection points (22); a plurality of movement limiters (23); an opening (24); a recess (26); and a tray (27) having a splash cover (28).

[0074] The body (21) is substantially a rectangular prism. Two edges of the body (21) are chamfered to create chamfered edges (21b, 21c). It will be understood that in other embodiments of the container (20), the body (21) may have a different shape. The body (21) of the container (20) may be formed from multiple individual components. This may be advantageous for manufacturing considerations. The body (21) is generally hollow. That is, the body (21) generally forms a cavity. The cavity may be referred to as a storage area. The opening (24) is an opening located on the upper surface (21a) of the body (21). It will be recognized that the upper surface (21a) of the body (21) is intended to point toward the surface of the body (21) facing in the opposite direction to the direction in which gravity acts during use. That is, in use, the upper surface (21a) can generally be described as being on another surface of the main body (21). The opening (24) can be described as a hole or a cutout. The opening (24) provides a fluid connection between the cavity within the main body (21) and the environment in which the container (20) is placed.

[0075] The plurality of connection points (22) may allow the container (20) to be connected to the outer frame of the discharge system. Alternatively, the plurality of connection points may allow the container (20) to be connected to any other component. It will be recognized that each connection point (22) may include part of any standard mechanism for securing one component to another, as is well known in the art. The plurality of movement restraints (23) may prevent unwanted movement of the container (20). In particular, the plurality of movement restraints (23) may prevent unwanted movement of the container (20) when the container (20) is used as part of the discharge system. The plurality of movement restraints (23) protrude from the outer dimensions of the main body (21).

[0076] The collar (25) is a separate component of the component forming part of the main body (21). The collar (25) is in contact with the upper surface (21a) of the main body (21). The collar (25) extends from the upper surface (21a). The collar (25) generally extends from the upper surface (21a) in a direction perpendicular to the main plane of the upper surface (21a). In alternative embodiments, it may be recognized that the collar (25) may extend in a different direction. The collar (25) extends outward from the main body (21). That is, the collar (25) extends from the upper surface (21a) in a direction opposite to the direction in which the cavity of the main body (21) is positioned.

[0077] In a cross section perpendicular to the direction in which the collar (25) extends from the upper surface (21a) and in the portion of the collar extending over the upper surface (21a), the collar (25) is generally U-shaped. The portion of the collar (25) extending over the upper surface (21a) of the main body (21) may be referred to as the upper portion (25e) of the collar (25).

[0078] In a cross section perpendicular to the direction in which the collar (25) extends from the upper surface (21a) and in the portion of the collar that generally does not extend over the upper surface (21a), the collar (25) generally has a rectangular shape. The portion of the collar (25) that generally does not extend over the upper surface (21a) of the main body (21) may be referred to as the lower portion (25f) of the collar (25). Such a lower portion (25f) contains material only around the perimeter of the lower portion (25f) so that the lower portion (25f) includes a central hole. The lower portion (25f) forms a closed shape (partially extending into the main body (21) to form the opening (24).

[0079] Since the collar (25) is generally U-shaped at the upper portion (25e) of the collar (25), the collar (25) generally forms a notch (25a) between two extension portions (25b, 25c) that are perpendicular to each other. The notch (25a) can be described as an open portion of the collar (25). The collar (25) is positioned to partially surround the opening (24). In particular, the collar (25) forms the edge of the opening (24). Between the cavity within the body (21) and the environment in which the container (21) is placed, a fluid connection is provided through a conduit formed by the opening (24) and the collar (25).

[0080] The above-mentioned container (20) is oriented horizontally—that is, at a predetermined angle with respect to the ground (which may be in the y-direction). This is because the radiation source (SO) is also tilted with respect to the horizontal. In alternative embodiments, the container (20) may be oriented horizontally (i.e., the base of the container (20) may be oriented in the y-direction, i.e., parallel to the ground).

[0081] The recess (26) is defined by a portion of the upper surface (21a) adjacent to the notch (25a) of the collar (25). In particular, the recess (26) is defined by a portion of the upper surface (21a) that extends from the upper surface (21a) in the same direction as the direction in which the cavity of the main body (21) is positioned. The recess (26) may protrude only slightly from the upper surface (21a). The edge of the recess (26) is close to the collar (25). In particular, the extensions (25b, 25c) of the collar (25) partially surround the portion of the recess (26) so that the base of the notch (25a) is defined by the portion of the recess (26).

[0082] The recess (26) extends from the collar (25) to the edge of the upper surface (21a) of the main body (21). The tray (27) comprises a generally cubic component having an open face. The tray (27) may be substantially smaller than the main body (21) of the container (20). The tray (27) is positioned on the side (21d) of the main body (21). The tray (27) is positioned so that the open face of the tray (27) is close to the edge of the upper surface (21a) of the main body (21) to which the recess (26) extends. The splash cover (28) generally comprises a rectangular component. The splash cover (28) may be described as a sheet. The splash cover (28) may be attached to the tray (27). The splash cover (28) may be attached to the side of the tray (27) opposite to the side of the tray (21d) of the main body (21). The splash cover (28) extends from the tray (27) to at least partially cover the edge of the upper surface (21a) of the main body (21) where the recess (26) extends.

[0083] The body (21) may be formed from a material containing molybdenum. Advantageously, molybdenum has high corrosion resistance from tin, which makes the material containing molybdenum particularly suitable for forming the body (21). The body (21) may additionally include one or more additional materials to increase the strength of the body (21). The body (21) may be formed from a material containing titanium. The body (21) may be formed from a material containing zirconium. The body (21) may be formed from a material containing a titanium-zirconium-molybdenum alloy (referred to as TZM). Such a titanium-zirconium-molybdenum alloy may contain 99.4% molybdenum, 0.5% titanium, and 0.08% zirconium. This can be formed by adding TiC and ZrC to molybdenum to improve the strength characteristics of the material (compared to pure molybdenum).

[0084] The above collar (25) can be formed from a material including a ceramic material.

[0085] The collar (25) may be formed from a material comprising any composition of silicon oxide; magnesium oxide; aluminum oxide; potassium oxide; boron oxide; and / or fluorine. In particular, the collar (25) may be composed of a material comprising silicon oxide; magnesium oxide; aluminum oxide; potassium oxide; boron oxide; and fluorine. The material may include a material marketed as MACOR™ by Combing Inc., established in the United States.

[0086] The collar (25) may be formed from a material containing boron nitride (BN). The collar (25) may be formed from a material containing aluminum nitride (AlN). The collar (25) may be formed from a material containing boron nitride and aluminum nitride. The material may include commercially available materials such as SHAPAL™, SHAPAL™-M, and / or SHAPAL™ Hi-M Soft. The collar (25) may be formed from a material containing pyrolytic boron nitride, which may be referred to as PBN.

[0087] Several oxide compounds have been proposed herein. It will be recognized that the use of the term "oxide" in compounds may refer to any suitable oxide compound (e.g., dioxide, trioxide, etc.). In particular, silicon oxide may refer to a silicon atom bonded to two oxygen atoms (SiO2), which may be referred to as silica. Magnesium oxide may refer to a magnesium atom bonded to an oxygen atom (MgO), which may be referred to as magnesia. Aluminum oxide may refer to two aluminum atoms bonded to three oxygen atoms (Al2O3), which may be referred to as alumina. Potassium oxide may refer to two potassium atoms bonded to one oxygen atom (K2O). Boron oxide may refer to two boron atoms bonded to three oxygen atoms (B2O3).

[0088] FIG. 3 schematically illustrates a side view of the container (20).

[0089] When in use, the container (20) may be arranged to interface with the pipe of the discharge system (e.g., the pipe (30) shown in FIG. 1). FIG. 3 illustrates an overview of the section of the pipe (30) that interfaces with the container (20). The end of the pipe (30) is close to the opening (24) of the container (20). In particular, the end of the pipe (30) is at least partially enclosed by the collar (25) (in FIG. 3, the dotted line of the pipe (30) illustrates the section of the pipe partially enclosed by the collar (25)). The end of the pipe (30) is at least partially enclosed by the upper part (25e) of the collar (25). The upper part (25e) of the collar (25) may be described as a partial section of the pipe. (Unlike the upper portion (25e) above, the lower portion (25f) does not include a notch and therefore the lower portion (25f) has a closed shape.) The lower portion (25f) of the collar (25) can be described as an entire section of the pipe. The collar (25) can interface with the pipe (30) of the discharge system. When the pipe (30) interfaces with the collar (25), this can be described as the formation of a composite pipe comprising the pipe (30), the upper portion (25e) of the collar (25e), and the lower portion (25f) of the collar (25). The collar (25) further includes a flange portion (25d). The flange portion (25d) is arranged around the edge of the collar (25) so that when the pipe (30) interfaces with the collar (25), the flange portion (25d) is close to the pipe (30). The above flange portion (25d) is increased to the extent that the upper portion (25e) of the collar (25) partially surrounds the pipe (30).

[0090] As described above, tin can be discharged from within the sealed structure (9) of the radiation source (SO) into the container (20) through one or more pipes (such as pipe (30)). The flow of tin (31) through the pipe (30) is illustrated in FIG. 3. The flow of tin (31) exits from the end of the pipe (30). Next, the flow of tin (31) passes through the opening (l4). Then, the flow of tin (31) enters the cavity of the body (21) of the container (20). By this, the container (20) can receive and collect tin from the discharge system of the radiation source (SO).

[0091] Known containers for storing liquid tin are formed of stainless steel. Liquid tin can react with stainless steel. Stainless steel can be corroded by liquid tin. For example, in known containers for storing liquid tin, approximately 100 μm of stainless steel may be removed from the surface of the stainless steel during operation of such containers annually. This can cause failure of such containers. Impurities in the stainless steel can exacerbate this problem. Welding defects (due to the formation of stainless steel containers) can exacerbate this problem. Thermal stress (due to the formation of stainless steel containers) can exacerbate this problem. Temperature gradients within the container can also significantly exacerbate this problem.

[0092] As described above, according to one embodiment of the present invention, the body (21) may be formed of a material containing molybdenum (e.g., TZM as described above). Advantageously, corrosion of the body (21) (formed of a material containing molybdenum) by liquid tin may be negligible or may not occur at all. In particular, corrosion of the body (21) may be negligible or may not occur at the temperature at which the container (20) is maintained.

[0093] TZM can have a thermal conductivity approximately nine times greater than that of stainless steel. Therefore, advantageously, the heating and cooling times of the body (21) (formed from a material including TZM) may be shorter than the heating and cooling times of a container body formed from stainless steel. This can result in advantages regarding throughput (e.g., of a radiation source (SO) and a lithography device (LA)). Additionally, advantageously, it may be possible to use a heating device design that is simpler than the heating device design required for a stainless steel container. Such an improved design of a heating device may include one or more heating elements separated from the container (20). Such an improved design of a heating device may include one or more heating elements that do not need to be removed from the radiation source (SO) when the cavity of the container (20) is generally filled with tin.

[0094] TZM can have a coefficient of thermal expansion about three times lower than that of stainless steel. Therefore, advantageously, the thermal stress within the body (21) (formed from a material including TZM) can be lower than the thermal stress of a container body formed from stainless steel. This, advantageously, can make the design of the body (21) to be formed (compared to a container body made of stainless steel) simpler.

[0095] As described above, when the container (20) is used as part of the discharge system of the radiation source (SO), the flow of tin (31) can exit through the end of the pipe (30). When the container (20) is in use, the end of the pipe (30) is at least partially enclosed by the collar (25) (particularly by the upper part (25e) of the collar (25). The collar (25) can interface with the pipe (30) of the discharge system to form a composite pipe. Advantageously, as a result, tin can be efficiently delivered to the container (20). In particular, as a result, tin can be efficiently delivered to the cavity of the body (21) of the container (20) through the opening (24).

[0096] The flow of the tin (31) may generally include liquid tin. The tin may come into contact with the collar (25) after exiting the pipe (30). The tin may enter the cavity of the container (20) and then bounce back from the surface of the cavity toward the opening (24). The container (20) may be heated. In particular, a heating device may heat the container (21) above the melting point of tin so that the tin placed within the cavity of the container (21) becomes liquid. However, the temperature of the collar (25) may be lower than the melting point of tin. This may be due to the thermal properties of the collar (25) and / or the accessibility of the collar (25) to the heating element of the heating device. For example, the collar (25) may be formed of a material having a relatively low thermal conductivity coefficient (e.g., a material having a lower thermal conductivity coefficient than the material on which the container (20) container (21) is formed). Additionally, there is contact resistance between the collar (25) and the body (21) of the container (20). Therefore, even though the body (21) of the container (20) may be maintained at a temperature of about 250°C, the temperature of the collar (25) may be below the melting point of tin (232°C). Even in a situation where the container (20) is intended to be heated to make all parts of the container (20) higher than the melting point of tin, the actual temperature of the collar (25) may be lower than the melting point of tin.

[0097] As described above, according to one embodiment of the present invention, the collar (25) may be formed from a ceramic material comprising MACOR™. MACOR™ is substantially non-wetting with respect to liquid tin. If tin comes into contact with the collar (25) (formed from MACOR™), the surface of the collar (25) may not be wetted. Additionally, MACOR™ may be substantially non-sticky with respect to liquid tin. The non-stick properties of MACOR™ can facilitate the removal of tin from the surface of the collar (25). Therefore, even if the collar (25) is at a temperature lower than the melting point of tin, there is little chance that tin will remain on the surface of the collar (25). Advantageously, this can prevent tin from accumulating around the opening (24). This can prevent the formation of a blockage in the discharge system. This is advantageous because any blockage of the above-mentioned exhaust system can result in a substantial reduction in throughput (e.g., of the radiation source (SO) and the lithography device (LA)).

[0098] In particular, earlier designs of vessels intended for use in radiation source exhaust systems do not include a collar (such as the collar (25)) formed of a ceramic material (such as MACOR™). Such earlier designs are prone to clogging due to the accumulation of tin. In such earlier designs, tin can wet the surface near the opening of the vessel. In such earlier designs, tin can adhere to the surface near the opening of the vessel. Consequently, over time, increasingly more tin can accumulate near the opening of the vessel. This reduces the efficiency of tin transfer into the vessel of such earlier designs. This ultimately leads to clogging of the exhaust system using such earlier designs.

[0099] A new design container (20) according to one embodiment of the present invention substantially mitigates (and can even eliminate) the risk of such blockage occurring. Accordingly, a new design container (20) according to an embodiment of the present invention provides significant advantages over known containers.

[0100] As described above, the radiation source (SO) may include a mechanism for providing hydrogen to the surfaces of components within the radiation source (SO). Such hydrogen may be delivered in the form of hydrogen gas. High-energy radiation within the radiation source (SO) may generate hydrogen radicals from the hydrogen gas. The hydrogen gas and / or hydrogen radicals may propagate through the exhaust system of the radiation source (SO). Thus, the hydrogen gas and / or hydrogen radicals may be present near the vessel (20).

[0101] Most metal-containing materials may generally be non-wetting with respect to liquid tin under normal atmospheric conditions. This non-wetting characteristic may be attributed to an oxide layer formed on the surface of such materials. However, such an oxide layer can be removed in a hydrogen-containing environment. In particular, in an environment where hydrogen radicals are present, the oxide layer may be chemically reduced. This may result in increased wettability with tin. Therefore, it may be particularly difficult to prevent the accumulation of tin on the surface of the collar (25) due to the presence of hydrogen gas and / or hydrogen radicals.

[0102] A specific advantage of the container (20) according to an embodiment of the present invention is that MACOR™ is generally non-wetting and generally non-sticky to tin, even in the presence of hydrogen. Accordingly, a collar (25) formed from a material containing MACOR™ provides the aforementioned advantages even in particularly difficult environments created in the presence of hydrogen.

[0103] As described above, it will be recognized that the advantages that can be achieved by using a collar (25) formed from a material including MACOR™ can be achieved by using a collar (25) formed from any other given material. In particular, the same or similar advantages can be achieved by using a collar (25) formed from a material including: boron nitride; boron nitride and aluminum nitride (which may be commercially available as SHAPAL™, SHAPAL™-M, and / or SHAPAL™ Hi-M Soft); or pyrolytic boron nitride.

[0104] Another advantage of the container (20) according to an embodiment of the present invention is that the TZM (from which the main body (21) can be formed as described above) is substantially resistant to hydrogen embrittlement. This is particularly advantageous due to the possibility that hydrogen gas and / or hydrogen radicals may be present near the main body (21). Containers of known designs may be formed of stainless steel, which is susceptible to corrosion from tin due to the corrosion of iron (the main component of stainless steel) by tin. Therefore, the container (20) according to an embodiment of the present invention is particularly advantageous over containers of known designs.

[0105] The above-mentioned container (20) may be a replaceable component of the discharge system of the radiation source (SO). The container (20) may be inserted into the discharge system. The container (20) may be removed from the discharge system. In particular, the container (20) may be removed from the discharge system when the cavity of the main body (21) accommodates a certain amount of tin. Then, a new container (e.g., equivalent to the container (20)) may be inserted into the discharge system.

[0106] The container (20) can be reused. The container (20) can be removed from the discharge system when the cavity of the main body (21) contains a certain amount of tin. The tin can be substantially removed from the container (20). The tin may be in a liquid state. This can facilitate the removal of tin from the container (20). Afterward, the container (20) can be reinserted into the discharge system.

[0107] FIGS. 4A and 4B illustrate a process in which the vessel (20) can be inserted into the exhaust system of the radiation source (SO). FIG. 4A illustrates the relative positions of the pipe (30) and the vessel (20) before the vessel (20) is inserted into the exhaust system. FIG. 4B illustrates the relative positions of the pipe (30) and the vessel (20) after the vessel (20) has been inserted into the exhaust system (this is also illustrated in FIG. 3). The pipe (30) and the vessel (20) are shown with respect to the same fixed background grid in FIG. 4A and 4B.

[0108] When the above container (20) is inserted into the discharge system, the pipe (30) of the discharge system can be maintained in a fixed state relative to the radiation source (SO). To insert the above container (20) into the discharge system, the container (20) can be moved in the insertion direction (32).

[0109] Advantageously, the U-shaped cross-section of the upper portion (25e) of the collar (25) allows the container (20) to be inserted into the discharge system, so that the collar (25) at least partially surrounds the end of the pipe (30), thereby forming a composite pipe. In particular, the notch (25a) provides a space through which the end of the pipe (30) can pass when the container (20) is inserted into the discharge system. Thus, the notch (25a) and the flare portion (25d) (see FIG. 2) provide a mechanism through which an advantageous connection between the container (20) and the pipe (30) can be achieved.

[0110] Tin may come into contact with the upper surface (21a) of the main body (21). The discharge system may be configured such that any tin coming into contact with the upper surface (21a) may come into contact with the portion of the upper surface (21a) that generally constitutes the recess (26). The notch (25a) of the collar (25) and the recess (26) may be arranged so that any tin propagating through the notch (25a) (e.g., tin bouncing out of the opening (24) from the cavity of the main body (21), tin coming into contact directly with the collar (25) from the pipe (30)) may be located in the recess (26).

[0111] The container (20) may be oriented at a predetermined angle relative to the horizontal—i.e., relative to the ground—as described above and as illustrated in FIGS. 3, 4a, and 4b. TZM may be non-wetting with respect to tin (as described above, the body (21) may be formed from the TZM). TZM may be non-sticky with respect to tin. Tin placed on the recess (26) (which may generally be in a liquid state) may propagate under the action of gravity toward the edge of the upper surface (21a) on which the tray (27) is placed. Such propagation of tin may be advantageously facilitated by the non-wetting and non-wetting properties of TZM. One or more edges of the recess may guide the trajectory of the tin so that the tin propagates toward the tray (27). The tin may enter the tray (27). The above splash cover (28) can facilitate the reception and / or retention of tin in the tray (27).

[0112] Advantageously, the recess (26), tray (27), and splash cover (28) can prevent the flow of tin (31) from contaminating the discharge system or other components. The recess (26), tray (27), and splash cover (28) can collect tin escaping from the pipe (30). The recess (26), tray (27), and splash cover (28) can collect tin that comes into contact with the container (20) when the container (20) is inserted into the discharge system or removed from the discharge system.

[0113] Although specific references regarding the use of lithography devices in the manufacture of ICs are mentioned in this document, it should be understood that the lithography devices described herein may have other applications. Possible other applications include guidance and detection patterns for the manufacture of integrated optical systems, magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), thin-film magnetic heads, etc.

[0114] Although specific references to embodiments of the present invention in this document are made in the context of lithography devices, embodiments of the present invention may be used in other devices. Embodiments of the present invention may form part of a mask inspection device, a measuring device, or any device that measures or processes an object such as a wafer (or other substrate) or a mask (or other patterning device). Such a device may generally be referred to as a lithography tool. Such a lithography tool may use vacuum conditions or ambient (non-vacuum) conditions.

[0115] Where the above circumstances permit, embodiments of the present invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the present invention may also be implemented as instructions stored on a machine-readable medium that can be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read-only memory (ROM); random access memory (RAM); magnetic storage medium; optical storage medium; flash memory device; electrical, optical, acoustic, or other forms of radio signals (e.g., carrier waves, infrared signals, digital signals, etc.). Additionally, firmware, software, routines, and instructions may be described herein as performing specific tasks. However, such description is merely for convenience, and in reality, such tasks are initiated by a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, etc., and in such cases, actuators or other devices become able to interact with the physical world.

[0116] Although specific embodiments of the present invention have been described above, it should be understood that the invention may be practiced differently from as described. The above descriptions are for illustrative purposes only and not for limitation. Accordingly, it will be apparent to those skilled in the art that the present invention may be modified without departing from the scope of the claims described below.

Claims

Claim 1 A vessel arranged to receive waste from a laser-generated plasma radiation source, comprising: a first portion defining a chamber; and a second portion defining at least partially an inlet to said chamber; wherein, in use, said waste enters said chamber through said inlet to said chamber, said second portion is formed of a material including a ceramic material, and said first portion is formed of a first material different from the material on which said second portion is formed. Claim 2 A container according to claim 1, wherein the first portion is formed of a material containing molybdenum. Claim 3 In claim 1, the ceramic material comprises a container containing boron and / or fluorine. Claim 4 In claim 1, the ceramic material comprises: silicon oxide; magnesium oxide; aluminum oxide; potassium oxide; boron oxide; and fluorine, forming a container. Claim 5 A container according to claim 1, wherein the ceramic material comprises a metal nitride. Claim 6 In claim 5, the ceramic material comprises a container. Claim 7 In claim 5, the ceramic material comprises a container including aluminum nitride. Claim 8 delete Claim 9 A laser-generated plasma radiation source comprising a vessel according to any one of claims 1 to 7. Claim 10 A laser-generated plasma radiation source comprising a component for use in an exhaust system of a radiation source, wherein the component at least partially defines the inlet of a chamber arranged to receive waste of the radiation source—the chamber being defined by a first portion—the component comprises a ceramic material comprising boron and / or fluorine, and the first portion defining the chamber being formed of a first material different from the material on which the component is formed. Claim 11 In claim 10, the ceramic material comprises: silicon oxide; magnesium oxide; aluminum oxide; potassium oxide; boron oxide; and fluorine, a laser-generated plasma radiation source. Claim 12 In claim 10, the above component is a laser-generated plasma radiation source comprising a ceramic material including boron nitride. Claim 13 In claim 10, the component is a laser-generated plasma radiation source comprising a ceramic material including aluminum nitride. Claim 14 A radiation source according to any one of claims 10 to 13, wherein the radiation source further comprises a mechanism for providing hydrogen to one or more surfaces within the radiation source. Claim 15 A radiation source according to any one of claims 10 to 13, wherein the component is a pipe configured to transport waste of the radiation source. Claim 16 delete Claim 17 delete

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