EUV utilization system and method

Abstract

An EUV utilization system includes a radiation source including a drive laser configured to generate drive laser radiation for irradiating a fuel and thereby generating extreme ultraviolet radiation. The EUV utilization system includes an EUV utilization device configured to receive extreme ultraviolet radiation directed through an optical aperture located between the radiation source and the EUV utilization device. The EUV utilization device includes a radiation shield configured to block propagation of the drive laser radiation through at least a portion of the optical aperture.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to European Application No. 22216593.8, filed on December 23, 2022, and the entire content of this European application is incorporated herein by reference. Technical field

[0003] The present invention relates to an EUV utilization system, such as (for example) a lithography system or an inspection system (e.g., for mask, wafer, or reticle inspection and methods), and in particular, to the generation of radiation for EUV utilization systems and methods. Background art

[0004] The EUV utilization device can be, for example, a lithography system or an inspection device. The inspection system can be configured to inspect potential defects of a mask. It can also be configured to inspect other components, such as (for example) a wafer or a reticle. This can be achieved by irradiating the component with EUV light generated by means of an EUV source container. The inspection device can include an irradiation system and an optical detection system. The EUV light can be reflected to the component to be inspected by means of the optical detection system. In this way, an image can be formed on the detector. Such a detector can be, for example, a time - delay integration camera.

[0005] A lithography apparatus is a machine configured to apply a desired pattern onto a substrate. A lithography apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A lithography apparatus can, for example, project a pattern at a patterning device (e.g., a mask) onto a layer of radiation - sensitive material (resist) provided on a substrate.

[0006] To project a pattern onto a substrate, a lithography apparatus can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the features that can be formed on the substrate. Compared to a lithography apparatus using radiation having a wavelength of, for example, 193 nm, a lithography apparatus using extreme ultraviolet (EUV) radiation having a wavelength in the range of 4 nm to 20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form smaller features on the substrate.

[0007] A lithography system includes a radiation source configured to generate EUV radiation and a lithography apparatus configured to use the EUV radiation. The radiation source includes a drive laser configured to direct drive laser radiation onto fuel droplets (e.g., tin) and convert the fuel droplets into a plasma that subsequently emits EUV radiation. The EUV radiation is directed from the radiation source to the lithography apparatus through an optical aperture that separates the radiation source from the lithography apparatus. At least some of the drive laser radiation can propagate from the radiation source through the optical aperture to the lithography apparatus and adversely affect one or more components of the lithography apparatus.

[0008] Known lithographic apparatuses and methods can be limited in terms of managing the ability to drive laser radiation. It is desirable to provide a lithographic apparatus and method that avoid or mitigate one or more problems of the prior art, whether the problem is recognized herein or elsewhere. SUMMARY OF THE INVENTION

[0009] According to a first aspect of the present disclosure, there is provided an EUV utilization system. Although the remainder of this specification focuses primarily on lithographic systems, it should be understood that the underlying concepts can be readily applied to any other EUV utilization, such as EUV inspection systems, particularly mask inspection systems, and even more particularly actinic mask inspection systems.

[0010] The lithographic system includes a radiation source that includes a drive laser configured to generate drive laser radiation for irradiating fuel and thereby generating extreme ultraviolet radiation. The lithographic system includes a lithographic apparatus configured to receive the extreme ultraviolet radiation that is guided through an optical aperture located between the radiation source and the lithographic apparatus. The lithographic apparatus includes a radiation shield configured to block the propagation of the drive laser radiation through at least a portion of the optical aperture.

[0011] The drive laser radiation entering the lithographic apparatus through the optical aperture may adversely affect one or more components of the lithographic apparatus. For example, unwanted thermal deformation of components (such as one or more mirrors, patterning devices, substrates, etc.) caused by the drive laser radiation may (e.g., by introducing focus and / or overlay errors) reduce the imaging performance of the lithographic apparatus and / or damage the components, and thereby reduce the operating life of the components. This may in turn require more frequent repair and / or maintenance of the optical components, thereby reducing the amount of time the lithographic system can remain operational. By using a radiation shield to block the drive laser radiation, the lithographic apparatus can be protected from these negative effects. However, the radiation source generates fuel debris (e.g., tin debris) during the generation of extreme ultraviolet radiation. If the radiation shield is located in the radiation source, the radiation shield may collect the fuel debris and then emit the debris when heated by the drive laser radiation. The fuel debris may travel through the optical aperture into the lithographic apparatus and adversely affect one or more components of the lithographic apparatus. For example, the fuel debris may damage and / or otherwise reduce the operating life of one or more mirrors of the lithographic apparatus. As another example, the fuel debris may impinge on the patterning device (i.e., the mask) present in the lithographic apparatus, and thereby adversely affect the imaging of the patterning device, resulting in faulty devices manufactured by the lithographic apparatus. By positioning the radiation shield in the lithographic apparatus rather than in the radiation source, the present invention advantageously reduces the amount of both drive laser radiation and fuel debris entering the lithographic apparatus. The radiation shield is exposed to less fuel debris when positioned in the lithographic apparatus rather than in the radiation source, and thus does not act as a source of fuel debris when heated by the drive laser radiation. Additionally, by positioning the radiation shield in the lithographic apparatus rather than in the radiation source, the radiation shield is exposed to less extreme conditions (e.g., reduced temperature and reduced exposure to fuel debris), thus enabling greater design flexibility for the radiation shield. For example, the lower thermal load may mean that the radiation shield can be smaller in volume and / or more compact, as less heat dissipation is required. By making the radiation shield more compact, the transmission of EUV radiation through the lithographic apparatus can be increased. Increasing the transmission of EUV radiation can in turn increase the throughput of the lithographic system.

[0012] The radiation source may be a laser-produced plasma (LPP) radiation source.

[0013] The drive laser may include a CO2 laser. The drive laser may be configured to produce pulsed drive laser radiation. The drive laser may be configured to produce a pulsed drive laser radiation having a power of about 28 kW. The drive laser may be configured to produce drive laser radiation having a wavelength (e.g., about 10 µm) within a closed interval range between about 9 µm and about 11 µm.

[0014] The optical aperture may correspond to the intermediate focus (i.e., the focus) of the EUV radiation collector present in the radiation source. The EUV radiation collector may be configured to collect EUV radiation emitted by the fuel and redirect the EUV radiation through the optical aperture.

[0015] The radiation shield includes metals such as, for example, tungsten, molybdenum, etc.

[0016] The radiation shield may be configured to block all drive laser radiation propagating through the optical aperture.

[0017] The radiation shield may be positioned adjacent to the optical aperture. The radiation shield may be positioned about 10 cm or more away from the optical aperture. The radiation shield may be positioned about 1 m or closer to the optical aperture.

[0018] The lithographic apparatus may include an illumination system configured to condition an extreme ultraviolet radiation beam for illuminating a patterning device. The illumination system may include a mirror configured to reflect extreme ultraviolet radiation. The radiation shield may be attached to the mirror.

[0019] The lithographic apparatus may include an illumination system configured to condition an extreme ultraviolet radiation beam for illuminating a patterning device. The illumination system may include a fuel shield configured to protect components of the illumination system from fuel debris generated by the radiation source. The radiation shield may be attached to the fuel shield.

[0020] The radiation source may include a first beam collector configured to block at least a portion of the drive laser radiation that does not propagate through the optical aperture.

[0021] The lithographic apparatus may include a second beam collector. The radiation shield may include a mirror configured to direct the portion of the drive laser radiation propagating through the optical aperture to the second beam collector.

[0022] The first beam collector may be disposed on the structure forming the optical aperture. The second beam collector may be disposed on the structure forming the optical aperture.

[0023] The lithographic system may include a cooling system. The cooling system may be configured to actively cool the first beam collector. The cooling system may be configured to actively cool the second beam collector.

[0024] The radiation source may be configured to generate a cone of extreme ultraviolet radiation. The cone may include a hole in which no extreme ultraviolet radiation is present. The radiation shield may be positioned at a location in the lithographic apparatus that at least partially coincides with the hole of the cone of extreme ultraviolet radiation. The radiation shield may be positioned at a location in the lithographic apparatus that completely coincides with the hole of the cone of extreme ultraviolet radiation.

[0025] According to a second aspect of the present disclosure, there is provided a method of providing extreme ultraviolet radiation to a lithographic apparatus. The method includes irradiating a fuel with drive laser radiation to generate extreme ultraviolet radiation. The method includes guiding the extreme ultraviolet radiation through an optical aperture to direct the extreme ultraviolet radiation to the lithographic apparatus. The method includes blocking the propagation of at least a portion of the drive laser radiation through the optical aperture.

[0026] The method may include blocking all of the drive laser radiation that propagates through the optical aperture.

[0027] The method may include blocking at least a portion of the drive laser radiation that does not propagate through the optical aperture.

[0028] The method may include using active cooling to dissipate heat generated by blocking the portion of the drive laser radiation that does not propagate through the optical aperture.

[0029] According to a third aspect of the present disclosure, there is provided a method of manufacturing a lithographic system. The method includes providing a radiation source that includes a drive laser configured to generate drive laser radiation for irradiating a fuel and thereby generating extreme ultraviolet radiation. The method includes providing a lithographic apparatus configured to receive extreme ultraviolet radiation guided through an optical aperture located between the radiation source and the lithographic apparatus. The method includes arranging a radiation shield in the lithographic apparatus to block the propagation of at least a portion of the drive laser radiation through the optical aperture.

[0030] The method may include positioning the radiation shield adjacent to the optical aperture.

[0031] The lithographic apparatus may include an illumination system configured to condition an extreme ultraviolet radiation beam for illuminating a patterning device. The illumination system may include a mirror configured to reflect the extreme ultraviolet radiation. The method may include attaching the radiation shield to the mirror.

[0032] The lithographic apparatus may include an illumination system configured to condition an extreme ultraviolet radiation beam for illuminating a patterning device. The illumination system may include a fuel shield configured to protect components of the illumination system from fuel debris generated by the radiation source. The method may include attaching the radiation shield to the fuel shield.

[0033] The method may include providing a first beam collector configured to block at least a portion of the drive laser radiation that does not propagate through the optical aperture.

[0034] The method may include providing a second beam collector configured to block the propagation of the drive laser radiation through the portion of the optical aperture.

[0035] The method may include arranging a first beam collector on a structure forming an optical aperture. The method may include arranging a second beam collector on a structure forming an optical aperture.

[0036] The method may include providing a cooling system. The cooling system may be configured to actively cool the first beam collector. The cooling system may be configured to actively cool the second beam collector.

[0037] A radiation source may be configured to generate a cone of extreme ultraviolet radiation. The cone may include an aperture in which there is no extreme ultraviolet radiation. The method may include positioning a radiation shield at a location in a lithographic apparatus that at least partially coincides with the aperture of the cone of extreme ultraviolet radiation.

[0038] It will be appreciated that the various aspects of the invention may be combined. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

[0040] - Figure 1 A lithographic system including a lithographic apparatus, a radiation source, and a radiation shield, is schematically depicted in accordance with an embodiment of the present disclosure;

[0041] - Figure 2 A simplified diagram of a lithographic system is schematically depicted when at least a portion of the driving laser radiation propagates through the lithographic apparatus Figure 1 ;

[0042] - Figure 3 A lithographic system is schematically depicted in which the radiation shield is attached to a fuel shield;

[0043] - Figure 4 A lithographic system is schematically depicted in which the radiation shield is attached to a mirror of an illumination system of a lithographic apparatus;

[0044] - Figure 5 A lithographic system is schematically depicted in which the radiation shield is configured to act as a reflector;

[0045] - Figure 6 A flowchart showing a method of providing extreme ultraviolet radiation to a lithographic apparatus in accordance with an embodiment of the present disclosure;

[0046] - Figure 7 A flowchart showing a method of manufacturing a lithographic system in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION

[0047] Figure 1A lithography system is shown that includes a radiation source SO and a lithographic apparatus LA. The radiation source SO is an extreme ultraviolet (EUV) laser-produced plasma (LPP) radiation source and the lithographic apparatus LA is an EUV scanner. The radiation source SO is configured to generate an EUV radiation beam B and supply the EUV radiation beam B to the lithographic apparatus LA. The lithographic apparatus 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.

[0048] The illumination system IL is configured to condition the EUV radiation beam B before the EUV radiation beam B is incident on the patterning device MA. Additionally, the illumination system IL may include a faceted field mirror device 10 and a faceted pupil mirror device 11. The faceted field mirror device 10 and the faceted pupil mirror device 11 together provide a desired cross-sectional shape and a desired intensity distribution to the radiation beam B. In addition to or instead of the faceted field mirror device 10 and the faceted pupil mirror device 11, the illumination system IL may include other mirrors or devices.

[0049] After being so conditioned, the EUV radiation beam B interacts with the patterning device MA. As a result of this interaction, a patterned EUV radiation beam B’ is produced. The projection system PS is configured to project the patterned EUV radiation beam B’ onto the substrate W. For this purpose, 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’, thus forming an image with 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 illustrated in Figure 1 as having only two mirrors 13, 14, the projection system PS may include a different number of mirrors (e.g., six or eight mirrors).

[0050] The substrate W may include a previously formed pattern. In such a case, the lithographic apparatus LA aligns the image formed by the patterned EUV radiation beam B’ with the pattern previously formed on the substrate W.

[0051] A relative vacuum may be provided in the radiation source SO, in the illumination system IL, and / or in the projection system PS, i.e., a small amount of gas (e.g., hydrogen) at a pressure far below atmospheric pressure.

[0052] Figure 1The radiation source SO shown belongs to a type that can be referred to as a laser-produced plasma (LPP) source, for example. A drive laser 1, which can include, for example, a CO2 laser, is arranged to deposit energy via drive laser radiation 2 into a fuel such as tin (Sn) provided from a fuel emitter 3, for example. Although tin is mentioned in the following description, any suitable fuel can be used. The fuel can be in liquid form, for example, and can be a metal or an alloy, for example. The fuel emitter 3 can include a nozzle configured to guide molten tin, for example in the form of microdroplets, along a trajectory towards the plasma formation region 4. During operation of such an LPP radiation source, not all fuel microdroplets can be intercepted by the drive laser radiation 2 (for example, during a pause in EUV emission), and thus these microdroplets can be collected in a container (not shown). The radiation source SO can include a container that includes the captured fuel that can be provided to the fuel emitter 3 for reuse.

[0053] The drive laser radiation 2 is incident on the tin at the plasma formation region 4. The deposition of drive laser energy into the tin creates a tin plasma 7 at the plasma formation region 4. Radiation including EUV radiation is emitted from the plasma 7 during the de-excitation and recombination of the electrons and ions of the plasma. The EUV radiation from the plasma is collected and focused by a collector 5. The collector 5 includes, for example, a near-normal incidence radiation collector 5 (sometimes more commonly referred to as a normal incidence radiation collector). The collector 5 can have a multilayer mirror structure arranged to reflect EUV radiation (for example, EUV radiation having a desired wavelength such as 13.5 nm). The collector 5 can have an elliptical configuration with two foci. The first of the foci can be at the plasma formation region 4, and the second of the foci can be at an intermediate focus 6, as discussed below.

[0054] The drive laser 1 can be spatially separated from the radiation source SO. In such a case, the drive laser radiation 2 can be transmitted from the drive laser 1 to the radiation source SO by means of a beam delivery system (not shown) that includes, for example, suitable steering mirrors and / or beam expanders and / or other optical components. The drive laser 1, the radiation source SO, and the beam delivery system can be considered together as a radiation system.

[0055] The radiation reflected by the collector 5 forms an EUV radiation beam B. The EUV radiation beam B is focused at the intermediate focus 6 to form an image of the plasma present at the plasma formation region 4 at the intermediate focus 6. The image at the intermediate focus 6 serves as a virtual radiation source for an illumination system IL. The radiation source SO is arranged such that the intermediate focus 6 is located at or near an opening 8 in the enclosure structure 9 of the radiation source SO. The opening 8 can be referred to as an optical aperture 8.

[0056] Figure 2Schematically depicts when at least a portion of the drive laser radiation 2a propagates through the optical aperture 8 Figure 1 A simplified diagram of a lithographic system. The optical aperture 8 may be formed by an opening in the enclosure structure 9 of the radiation source SO. The optical aperture 8 may be considered to be located on the dividing line 110 between the radiation source SO and the lithographic apparatus LA. It should be understood that the dividing line 110 is not a physical structure and is only shown to aid understanding Figure 2 . In Figure 2 the example, three portions 2a to 2c of the drive laser radiation are shown. The first portion 2a of the drive laser radiation propagates through the optical aperture 8 and thus travels from the radiation source SO to the lithographic apparatus LA. The drive laser radiation 2a entering the lithographic apparatus LA through the optical aperture 8 may adversely affect one or more components of the lithographic apparatus LA. The drive laser radiation 2a may transfer heat to one or more components and thus cause undesirable thermal deformation of one or more components. The drive laser radiation 2a may damage the components and thus reduce the operating life of the components. This may in turn require more frequent repair and / or maintenance of the components, thereby reducing the amount of time the lithographic system can remain operational. For example, the undesirable thermal deformation and / or damage to components such as one or more mirrors 10, 11, 13, 14 ( Figure 1 shown in), the patterning device MA and / or the substrate W ( Figure 1 shown in) caused by the drive laser radiation 2a can degrade the imaging performance of the lithographic apparatus LA, for example, by introducing focus errors and / or overlay errors.

[0057] The lithographic apparatus LA includes a radiation shield 100 configured to block the portion of the drive laser radiation 2a that propagates through the optical aperture 8. The radiation shield 100 is used to protect the components of the lithographic apparatus LA from the adverse effects of undesirable thermal deformation and / or damage to the components caused by the drive laser radiation 2a. However, the position of the radiation shield 100 relative to the fuel debris 120 generated in the radiation source SO is important.

[0058] The radiation source SO generates fuel debris 120 (e.g., tin debris) during the generation of EUV radiation. If the radiation shield 100 is located in the radiation source SO, the radiation shield 100 may be contaminated by the fuel debris 120 (e.g., molten tin) and then later emit the fuel debris 120 through the optical aperture 8 and into the lithographic apparatus LA. The emission of the fuel debris 120 from the radiation shield 100 can be caused by the high temperatures reached during the operation of the radiation SO (e.g., greater than 1000 ºC) and / or caused by chemical effects occurring within the radiation source SO. For example, molten tin 120 may be collected on the radiation shield 100 and subsequently released from the radiation shield 100 when the drive laser radiation 2a heats the radiation shield 100 to a temperature above the melting point of tin. As another example, hydrogen gas may be supplied to the radiation source SO to reduce contamination of the surface within the radiation source SO by fuel debris 120. The hydrogen gas may be heated to convert it into free radicals that can remove the contamination from the surface within the radiation source SO. However, the free radicals may interact with the molten tin 120, thereby causing small particles of tin to be ejected from the surface of the radiation shield 100. This phenomenon may be referred to as "tin splashing".

[0059] If the radiation shield 100 is located within the radiation source SO, fuel debris released from the radiation shield 100 (e.g., by tin splashing) may travel through the optical aperture 8, enter the lithographic apparatus LA and adversely affect one or more components of the lithographic apparatus LA. For example, the fuel debris may damage and / or otherwise reduce the operating life of one or more mirrors 10, 11, 13, 14 ( Figure 1 shown in). As another example, if the radiation shield 100 is located within the radiation source SO, fuel debris emitted by the radiation shield 100 may impinge on the patterning device MA and / or the substrate W present in the lithographic apparatus LA and may reduce the imaging performance of the lithographic apparatus LA, for example, by introducing focus errors and / or overlay errors. This in turn can lead to defective devices being manufactured by the lithographic apparatus LA.

[0060] By positioning the radiation shield 100 within the lithographic apparatus LA rather than within the radiation source SO, contamination of the radiation shield 100 by fuel debris 120 is reduced or completely avoided. This significantly reduces the likelihood that the radiation shield 100 becomes a source of fuel debris compared to positioning the radiation shield 100 within the radiation source SO, and thereby reduces contamination of the lithographic apparatus LA by fuel debris 120.

[0061] Positioning the radiation shield 100 within the radiation source SO may interfere with the intended flow of hydrogen gas and / or free radicals within the radiation source SO, which may in turn reduce the decontamination of surfaces within the radiation source SO. For example, the portion of structure 9 that forms the optical aperture 8 within the radiation source SO and separates the fuel-rich debris environment of the radiation source SO from the cleaner environment of the lithography apparatus LA may be referred to as the fuel shield 9. Fuel debris 120 impinges on the fuel shield 9 during operation of the radiation source SO. To remove the fuel debris and thereby decontaminate the fuel shield 9, a flow of free radicals (not shown) may be provided along the fuel shield 9. Positioning the radiation shield 100 adjacent to the fuel shield 9 within the radiation source SO may alter the intended direction of the free radicals and / or introduce an undesirable asymmetry in the flow of free radicals. This may in turn prevent decontamination of one or more surface regions of the fuel shield 9 by the free radicals, causing problematic fuel debris buildup on one or more surface regions of the fuel shield 9. By positioning the radiation shield 100 within the lithography apparatus LA rather than within the radiation source SO, the flow of hydrogen gas and / or free radicals is not disturbed. This significantly reduces the buildup of fuel debris 120 on the surfaces of the radiation source SO (such as the fuel shield 9) compared to positioning the radiation shield 100 within the radiation source SO.

[0062] Typically, the radiation source SO environment is operated under more extreme conditions compared to the lithography apparatus LA. For example, the radiation source SO reaches temperatures above 1000 º °C and is exposed to fuel debris 120, whereas the lithography apparatus LA does not reach these extreme temperatures and is exposed to very little or no fuel debris 120. As another example, when the radiation shield 100 is located within the lithography apparatus LA, the radiation shield 100 may be exposed to less drive laser radiation 2a compared to when it is located within the radiation source SO, because the fuel shield 9 may block portions 2b, 2c of the drive laser radiation that would otherwise impinge on the radiation shield 100. Thus, when the radiation shield 100 is located within the lithography apparatus LA rather than within the radiation source SO, the radiation shield 100 may be subjected to a lower thermal load. By positioning the radiation shield 100 within the lithography apparatus LA rather than within the radiation source SO, the radiation shield 100 is exposed to less extreme conditions. Thus, greater design flexibility for the radiation shield 100 is achieved. For example, since less drive laser radiation 2a power impinges on the radiation shield 100 when the radiation shield is located within the lithography apparatus LA rather than within the radiation source SO, the radiation shield 100 may require less material to absorb the associated thermal load. Thus, when the radiation shield 100 is located within the lithography apparatus LA rather than within the radiation source SO, the radiation shield 100 and / or the arm configured to support the radiation shield 100 (with respect to Figures 3 to 5The one shown and described ()) can be more compact and / or lighter. As another example, since the beam diameter of the drive laser radiation 2a (e.g., due to the proximity to the intermediate focus 6) can be smaller in the lithography apparatus LA than in the radiation source SO. Thus, when the radiation shield 100 is located in the lithography apparatus LA instead of the radiation source SO, the radiation shield 100 may require a smaller size to block the portion of the drive laser radiation 2a passing through the optical aperture 8, and thus can be more compact and / or lighter. Under the condition that the radiation shield 100 is more compact and / or lighter, the arm (with respect to Figures 3 to 5 shown and described) can also be smaller. When the radiation shield 100 is located in the lithography apparatus LA instead of the radiation source SO, the size of the radiation shield 100 can be at least as small as one half, e.g., as small as about one fifth.

[0063] By making the radiation shield 100 more compact, the transmission of EUV radiation through the lithography apparatus LA can be improved. As other examples, compared with the case where the radiation shield is located in the radiation source SO, when the radiation shield 100 is located in the lithography apparatus LA, the size and / or shape of the radiation shield 100 can be different and / or made of a wider range of materials.

[0064] Referring to Figure 1 , the EUV radiation B generated by the radiation source SO can be in the form of a conical body having a hole in its center. The hole in the conical body of the EUV radiation can correspond to the gap in the collector 5 through which the drive laser radiation 2 is guided to the plasma formation region 7. The radiation shield 100 can be positioned within the lithography apparatus LA at a position coinciding or aligned with the hole in the conical body of the EUV radiation B such that no EUV radiation B on the substrate is blocked by the radiation shield 100, while substantially all of the drive laser radiation 2a passing through the optical aperture 8 is blocked by the radiation shield 100. By positioning the radiation shield 100 in the lithography apparatus LA instead of in the radiation source SO, the radiation shield 100 can be positioned in a position coinciding or aligned with the hole in the conical body of the EUV radiation B such that substantially no EUV radiation B is blocked by the radiation shield 100, while substantially all of the drive laser radiation 2a passing through the optical aperture 8 is blocked by the radiation shield 100.

[0065] By blocking the drive laser radiation 2a, the radiation shield 100 is configured to absorb (i.e., act as a beam stop), redirect (e.g., reflect), or otherwise prevent the drive laser radiation 2a from interacting with components of the lithographic apparatus LA that are not intended to interact with the drive laser beam 2a. Accordingly, the design of the radiation shield 100 can be determined at least in part by the characteristics of the drive laser radiation 2a that is expected to impinge on the radiation shield 100 together with the associated thermal load. For example, the drive laser radiation 2a can have a wavelength in the closed interval range between about 9 µm and about 11 µm. For example, the drive laser radiation 2a can have a power between about 10 kW and about 50 kW. The radiation shield 100 can be formed of a metal such as, for example, tungsten or molybdenum. The radiation shield 100 can be configured to block all of the drive laser radiation 2a that propagates through the optical aperture 8. The size and / or shape of the radiation shield 100 can be determined at least in part by the spatial extent (e.g., beam diameter) of the drive laser radiation 2a at the location where the radiation shield 100 will be placed. The radiation shield 100 can have a diameter that is slightly larger than the beam diameter of the drive laser radiation 2a to ensure blocking of the drive laser radiation 2a. For example, the drive laser radiation 2a can have a beam diameter in the closed interval range between about 0.6 cm and about 2 cm, whereas the radiation shield 100 can have a diameter that is greater than the beam diameter of the drive laser radiation 2a and in the closed interval range between about 1 cm and about 5 cm. The spatial extent of the portion of the drive laser radiation 2a that propagates through the optical aperture 8 can be determined at least in part by the spatial extent (e.g., diameter) of the optical aperture 8. For example, the optical aperture 8 can have a diameter between about 3 mm and about 12 mm.

[0066] As previously discussed, by positioning the radiation shield 100 in the lithographic apparatus LA rather than in the radiation source SO, a greater portion of the drive laser radiation 2b, 2c can be incident on a surface of the radiation source SO such as, for example, the fuel shield 9. For example, when the radiation shield 100 is located in the lithographic apparatus LA, additional power of the drive laser radiation 2b, 2c can be incident on the fuel shield 9. The radiation source SO can include a first beam collector 105 configured to block at least a portion of the drive laser radiation 2b, 2c that does not propagate through the optical aperture 8. The first beam collector 105 can be disposed on one or more regions of the fuel shield 9 that are expected to receive the drive laser radiation 2b, 2c. The first beam collector 105 can be configured to absorb substantially all of the drive laser radiation 2b, 2c incident on the first beam collector 105. Thus, the design of the first beam collector 105 can be determined at least in part by the characteristics of the drive laser radiation 2b, 2c expected to be incident on the first beam collector 105 together with the associated thermal load. The first beam collector 105 can be formed of a metal such as, for example, tungsten, molybdenum, or copper.

[0067] The radiation shield 100 can be positioned adjacent to the optical aperture 8. The radiation shield 100 can be positioned closer to the optical aperture 8 than any other component of the lithographic apparatus LA. For example, the radiation shield 100 can be located at a distance within the closed interval between about 10 cm and about 1 m from the center of the optical aperture 8. This can reduce or eliminate the risk that the radiation shield 100 interferes with EUV radiation propagating through the optical aperture 8 to the lithographic apparatus LA and / or interferes with components of the lithographic apparatus LA (e.g., Figure 1 the mirrors 10, 11 shown). Additionally, the spatial extent of the portion of the drive laser radiation 2a that propagates through the optical aperture 8 can be determined at least in part by the beam divergence of the drive laser radiation 2a. By positioning the radiation shield 100 adjacent to the optical aperture 8, the portion of the drive laser beam 2a is blocked before it can diverge further, and the risk of interaction of the portion of the drive laser radiation 2a with components of the lithographic apparatus LA is reduced.

[0068] Figures 3 to 5 An example showing different positions of the radiation shield 100 in the lithographic apparatus LA according to an embodiment of the present disclosure is presented. As discussed above, the lithographic apparatus LA includes an illumination system IL, and in Figures 3 to 5 the example, the radiation shield 100 is located at different positions within the illumination system IL. In Figure 3 the example, the radiation shield 100 is attached to the fuel shield 9. In Figure 4 and Figure 5 the example, the radiation shield 100 is attached to the faceted field mirror device 10 of the illumination system IL.Figures 3 to 5 In each of the examples, the radiation shield 100 is attached to a component of the lithography system by an arm 130. The arm 130 can be a rod configured to support the radiation shield 130. The arm 130 can be formed of a metal such as, for example, aluminum or steel. The arm 130 can be configured to hold the radiation shield 100 in a fixed position relative to the optical aperture 8.

[0069] In Figure 3 and Figure 4 the examples, the radiation shield 100 is configured to act as a beam collector and absorb substantially all of the propagation of the drive laser radiation 2a through the optical aperture 8. In Figure 5 the examples, the radiation shield 100 is configured to act as a reflector and redirect a portion of the propagation of the drive laser radiation 2a through the optical aperture 8 to a second beam collector 115. When the radiation shield 100 is configured to act as a reflector, the radiation shield 100 can be configured to reflect substantially all of the drive laser radiation 2a incident on the radiation shield 100. Thus, the design of the radiation shield 100 can be determined at least in part by the characteristics of the drive laser radiation 2a expected to be incident on the radiation shield 100. When the radiation shield 100 is configured to act as a reflector, the radiation shield 100 can be formed of a metal such as aluminum or steel. When the radiation shield 100 is configured to act as a reflector, the radiation shield 100 can include a multilayer mirror configured to reflect the wavelength of the drive laser radiation 2a (e.g., between about 9 µm and about 11 µm). When the radiation shield 100 is configured to act as a reflector, the radiation shield 100 can include a mirror structure similar to the mirror structure utilized in the drive laser 1.

[0070] In Figure 5 the examples, the second beam collector 115 is disposed on the upper surface of the fuel shield 9. The second beam collector 115 can be disposed at other locations on the fuel shield 9 or on another component of the illumination system IL. The second beam collector 115 can be configured to absorb substantially all of the drive laser radiation 2a incident on the second beam collector 115. Thus, the design of the second beam collector 115 can be determined at least in part by the characteristics of the drive laser radiation 2a expected to be incident on the second beam collector 115 together with the associated thermal load. The second beam collector 105 can be formed of a metal such as, for example, tungsten, molybdenum, or copper. The first beam collector 105 and / or the second beam collector 115 can be used to reduce or prevent undesired thermal deformation of the fuel shield 9.

[0071] Throughout Figures 2 to 5 , the lithography system includes a cooling system 140. In Figures 2 to 4In an example, the cooling system 140 is configured to actively cool the first beam collector 105. In Figure 5 In an example, the cooling system 140 is configured to actively cool the first beam collector 105 and the second beam collector 115. The cooling system 140 may include one or more channels configured to convey a cooling fluid. The cooling fluid may be, for example, water. The channels may contact the first beam collector 105 and / or the second beam collector 115 and / or be positioned adjacent the beam collectors to allow transfer of thermal energy from the first beam collector 105 and / or the second beam collector 115 to the cooling fluid. The cooling fluid may then be directed away from the first beam collector 105 and / or the second beam collector 115 and the cooling fluid may be directed to a heat trap and / or a temperature regulator to remove the absorbed thermal energy from the cooling fluid. The cooled cooling fluid may then be redirected via the channels to the first beam collector 105 and / or the second beam collector 115, thereby providing a continuous cooling cycle. The lithography system may include one or more pre-existing cooling systems that may be modified to provide cooling to the first heat trap 105 and / or the second heat trap 115.

[0072] Figure 6 A flowchart illustrating a method of providing extreme ultraviolet radiation to a lithography apparatus according to an embodiment of the present disclosure is shown. The first step 200 of the method includes irradiating a fuel with drive laser radiation to generate extreme ultraviolet radiation. The first step 200 may include using an LPP radiation source such as Figure 1 the radiation source SO shown in. The second step 201 of the method includes directing the extreme ultraviolet radiation through an optical aperture to the lithography apparatus. The second step 201 of the method may include using a radiation collector 5 to direct EUV radiation B through Figure 1 the optical aperture 8 of the lithography system of. The third step 202 of the method includes blocking the propagation of the drive laser radiation through at least a portion of the optical aperture. The third step 202 of the method may include using Figures 1 to 5 a radiation shield 100 shown in any of the examples of.

[0073] Figure 7 A flowchart illustrating a method of manufacturing a lithography system according to an embodiment of the present disclosure is shown. The first step 300 of the method includes providing a radiation source that includes a drive laser configured to generate drive laser radiation for irradiating a fuel and thereby generating extreme ultraviolet radiation. The first step 300 of the method may include providing an LPP radiation source SO, as Figure 1The LPP radiation source SO shown in. The second step 301 of the method includes providing a lithographic apparatus configured to receive extreme ultraviolet radiation guided through an optical aperture located between the radiation source and the lithographic apparatus. The second step 301 of the method may include providing an EUV lithographic apparatus LA, such as Figure 1 the EUV lithographic apparatus LA shown in, and arranging the lithographic apparatus LA relative to the radiation source SO to form an optical aperture 8. The third step 302 of the method includes arranging a radiation shield in the lithographic apparatus to block the propagation of the drive laser radiation through at least a portion of the optical aperture. The third step 302 of the method may include providing Figures 1 to 5 a radiation shield 100 of any one of the examples of.

[0074] Article

[0075] 1. A lithographic system, comprising:

[0076] a radiation source including a drive laser configured to generate drive laser radiation for irradiating fuel and thereby generating extreme ultraviolet radiation; and

[0077] a lithographic apparatus configured to receive extreme ultraviolet radiation guided through an optical aperture located between the radiation source and the lithographic apparatus,

[0078] wherein the lithographic apparatus includes a radiation shield configured to block the propagation of the drive laser radiation through at least a portion of the optical aperture.

[0079] 2. The lithographic system according to Article 1, wherein the radiation shield is configured to block all of the drive laser radiation propagating through the optical aperture.

[0080] 3. The lithographic system according to Article 1 or Article 2, wherein the radiation shield is positioned adjacent to the optical aperture.

[0081] 4. The lithographic system according to any one of the preceding Articles, wherein the lithographic apparatus includes an illumination system configured to condition the extreme ultraviolet radiation beam for illuminating a patterning device, the illumination system including a mirror configured to reflect the extreme ultraviolet radiation, wherein the radiation shield is attached to the mirror.

[0082] 5. The lithographic system according to any one of the preceding Articles, wherein the lithographic apparatus includes an illumination system configured to condition the extreme ultraviolet radiation beam for illuminating a patterning device, the illumination system including a fuel shield configured to protect components of the illumination system from fuel debris generated by the radiation source, wherein the radiation shield is attached to the fuel shield.

[0083] 6. A lithographic system according to any one of the preceding clauses, wherein the radiation source includes a first beam collector configured to block at least a portion of the drive laser radiation that does not propagate through the optical aperture.

[0084] 7. A lithographic system according to clause 6, wherein the lithographic apparatus includes a second beam collector, and wherein the radiation shield includes a mirror configured to direct the portion of the drive laser radiation that propagates through the optical aperture towards the second beam collector.

[0085] 8. A lithographic system according to clause 7, wherein the first beam collector and / or the second beam collector is disposed on a structure forming the optical aperture.

[0086] 9. A lithographic system according to clause 7 or clause 8, including a cooling system configured to actively cool the first beam collector and / or the second beam collector.

[0087] 10. A lithographic system according to any one of the preceding clauses, wherein the radiation source is configured to generate a cone of extreme ultraviolet radiation, wherein the cone includes a hole in which there is no extreme ultraviolet radiation, and wherein the radiation shield is positioned at a location in the lithographic apparatus that at least partially coincides with the hole of the cone of extreme ultraviolet radiation.

[0088] 11. A method of providing extreme ultraviolet radiation to a lithographic apparatus, comprising:

[0089] irradiating a fuel with drive laser radiation to generate extreme ultraviolet radiation;

[0090] directing the extreme ultraviolet radiation through an optical aperture to direct the extreme ultraviolet radiation to the lithographic apparatus; and

[0091] blocking at least a portion of the propagation of the drive laser radiation through the optical aperture.

[0092] 12. The method according to clause 11, including blocking all of the drive laser radiation that propagates through the optical aperture.

[0093] 13. The method according to clause 11 or clause 12, including blocking at least a portion of the drive laser radiation that does not propagate through the optical aperture.

[0094] 14. The method according to clause 13, including using active cooling to dissipate heat generated by blocking the portion of the drive laser radiation that does not propagate through the optical aperture.

[0095] 15. A method of manufacturing a lithographic system, comprising:

[0096] Provide a radiation source, the radiation source including a drive laser configured to generate drive laser radiation for irradiating fuel and thereby generating extreme ultraviolet radiation;

[0097] Provide a lithographic apparatus configured to receive extreme ultraviolet radiation guided through an optical aperture located between the radiation source and the lithographic apparatus; and

[0098] Arrange a radiation shield in the lithographic apparatus to block the propagation of the drive laser radiation through at least a portion of the optical aperture.

[0099] 16. The method according to item 15, including positioning the radiation shield adjacent to the optical aperture.

[0100] 17. The method according to item 15 or item 16, wherein the lithographic apparatus includes an illumination system configured to condition the extreme ultraviolet radiation beam for illuminating a patterning device, the illumination system including a mirror configured to reflect the extreme ultraviolet radiation,

[0101] The method includes attaching the radiation shield to the mirror.

[0102] 18. The method according to item 15 or item 16, wherein the lithographic apparatus includes an illumination system configured to condition the extreme ultraviolet radiation beam for illuminating a patterning device, the illumination system including a fuel shield configured to protect components of the illumination system from fuel debris generated by the radiation source,

[0103] The method includes attaching the radiation shield to the fuel shield.

[0104] 19. The method according to any one of items 15 to 18, including providing a first beam collector configured to block at least a portion of the drive laser radiation that does not propagate through the optical aperture.

[0105] 20. The method according to item 19, including providing a second beam collector configured to block the propagation of the drive laser radiation through the portion of the optical aperture.

[0106] 21. The method according to item 20, including arranging the first beam collector and / or the second beam collector on a structure forming the optical aperture.

[0107] 22. The method according to item 20 or item 21, including providing a cooling system configured to actively cool the first beam collector or the second beam collector.

[0108] 23. The method according to any one of clauses 15 to 22, wherein the radiation source is configured to generate a cone of extreme ultraviolet radiation, wherein the cone includes a hole in which no extreme ultraviolet radiation is present,

[0109] wherein the method includes positioning the radiation shield in the lithographic apparatus at a location that at least partially coincides with the hole of the cone of extreme ultraviolet radiation.

[0110] Although the lithographic apparatus may be specifically referred to herein in the context of its use in IC manufacture, it should be understood that the lithographic apparatus described herein may have other applications. Possible other applications include the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, and the like.

[0111] Where circumstances allow, embodiments of the invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the invention may also be implemented as instructions stored on a machine-readable medium, which may 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 computer device. For example, a machine-readable medium may include: read only memory (ROM); random access memory (RAM); magnetic storage media; optical storage media; flash memory devices; electrical, optical, acoustic, or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.). Further, firmware, software, routines, instructions may be described herein as performing certain actions. However, it should be understood that such descriptions are for convenience only and that such actions are in fact caused by computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc., and may cause actuators or other devices to interact with the physical world when such operations are performed.

[0112] Although specific embodiments of the invention have been described above, it should be understood that the invention may be practiced in other ways different from those described. The above description is intended to be illustrative and not restrictive. Thus, those skilled in the art will appreciate that the described invention may be modified without departing from the scope of the claims set forth below.

Claims

1. An EUV utilization system, comprising: a radiation source including a drive laser configured to generate a drive laser beam for irradiating fuel and thereby generating extreme ultraviolet radiation; and an EUV utilization device configured to receive the extreme ultraviolet radiation guided through an optical aperture located between the radiation source and the EUV utilization device, wherein the EUV utilization device includes a radiation shield configured to block the propagation of at least a portion of the drive laser beam through the optical aperture.

2. The EUV utilization system according to claim 1, wherein, The radiation shield is configured to block all of the drive laser beam radiation propagating through the optical aperture.

3. The EUV utilization system according to claim 1 or claim 2, wherein The radiation shield is positioned adjacent to the optical aperture.

4. The EUV utilization system according to any one of the preceding claims, wherein, The EUV utilization device includes an illumination system configured to condition an extreme ultraviolet radiation beam for illuminating a patterning device, the illumination system including a mirror configured to reflect the extreme ultraviolet radiation, wherein the radiation shield is attached to the mirror.

5. The EUV utilization system according to any one of the preceding claims, wherein, The EUV utilization system includes an illumination system configured to condition the extreme ultraviolet radiation beam for illuminating a patterning device, the illumination system including a fuel shield configured to protect components of the illumination system from fuel debris generated by the radiation source, wherein the radiation shield is attached to the fuel shield.

6. The EUV utilization system according to any one of the preceding claims, wherein, The radiation source includes a first beam collector configured to block at least a portion of the drive laser beam radiation that does not propagate through the optical aperture.

7. The EUV utilization system according to claim 6, wherein, The EUV utilization device includes a second beam collector, and wherein the radiation shield includes a mirror configured to direct the portion of the drive laser beam radiation propagating through the optical aperture to the second beam collector.

8. The EUV utilization system according to claim 7, wherein, The first beam collector and / or the second beam collector is arranged on a structure forming the optical aperture.

9. The EUV utilization system according to claim 7 or claim 8, including a cooling system configured to actively cool the first beam collector and / or the second beam collector.

10. The EUV utilization system according to any one of the preceding claims, wherein, The radiation source is configured to generate a cone of extreme ultraviolet radiation, wherein the cone includes a hole in which there is no extreme ultraviolet radiation, and wherein the radiation shield is positioned at a location in the EUV utilization device that at least partially coincides with the hole of the cone of extreme ultraviolet radiation.

11. A method of providing extreme ultraviolet radiation to an EUV utilization device, comprising: irradiating fuel with a drive laser beam to generate extreme ultraviolet radiation; guiding the extreme ultraviolet radiation through an optical aperture to direct the extreme ultraviolet radiation to the EUV utilization device; and blocking the propagation of at least a portion of the drive laser beam through the optical aperture.

12. The method according to claim 11, including blocking all of the drive laser beam radiation propagating through the optical aperture.

13. The method according to claim 11 or claim 12, including blocking at least a portion of the drive laser beam radiation that does not propagate through the optical aperture.

14. The method according to claim 13, comprising: Use active cooling to dissipate heat generated by blocking that portion of the driving laser beam radiation that does not propagate through the optical aperture.

15. A method of manufacturing an EUV utilization system, comprising: providing a radiation source including a driving laser configured to generate a driving laser beam for irradiating fuel and thereby generating extreme ultraviolet radiation; providing an EUV utilization device configured to receive extreme ultraviolet radiation guided through an optical aperture located between the radiation source and the EUV utilization device; and arranging a radiation shield in the EUV utilization device to block propagation of the driving laser beam through at least a portion of the optical aperture.

16. The method according to claim 15, including positioning the radiation shield adjacent to the optical aperture.

17. The method according to claim 15 or claim 16, wherein The EUV utilization device includes an illumination system configured to condition an extreme ultraviolet radiation beam for illuminating a patterning device, the illumination system including a mirror configured to reflect the extreme ultraviolet radiation, The method includes attaching the radiation shield to the mirror.

18. The method according to claim 15 or claim 16, wherein The EUV utilization device includes an illumination system configured to condition the extreme ultraviolet radiation beam for illuminating a patterning device, the illumination system including a fuel shield configured to protect components of the illumination system from fuel debris generated by the radiation source, The method includes attaching the radiation shield to the fuel shield.

19. The method according to any one of claims 15 to 18, including providing a first beam collector configured to block at least a portion of the driving laser beam that does not propagate through the optical aperture.

20. The method according to claim 19, including providing a second beam collector configured to block the driving laser beam from propagating through the portion of the optical aperture.

21. The method according to claim 20, including arranging the first beam collector and / or the second beam collector on a structure forming the optical aperture.

22. The method according to claim 20 or claim 21, including providing a cooling system configured to actively cool the first beam collector or the second beam collector.

23. The method according to any one of claims 15 to 22, wherein The radiation source is configured to generate a cone of extreme ultraviolet radiation, wherein the cone includes an aperture in which there is no extreme ultraviolet radiation, wherein the method includes positioning the radiation shield in the EUV utilization device at a position that at least partially coincides with the aperture of the cone of extreme ultraviolet radiation.

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