Pellicle membrane for EUV utilization apparatus and method of manufacturing the same

Abstract

A membrane for use as a pellicle in an EUV-utilizing apparatus is provided, the membrane comprising randomly oriented uncoated carbon nanotubes having one or both of: i) an average diameter of less than 5 nm and a bundle (average) diameter of less than 30 nm, wherein the Young's modulus of the membrane is greater than 10 MPa; and ii) surface features that provide roughness to the nanotubes such that relative movement of the CNT tubes in the membrane is substantially blocked or inhibited. Also provided is a pellicle for an EUV-utilizing apparatus, the pellicle comprising such a membrane and a support frame for supporting the membrane, and an EUV-utilizing apparatus comprising such a membrane or pellicle. Also provided is a method of manufacturing a membrane for an EUV-utilizing apparatus.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to European Application 24167405.0, filed on 28 March 2024; European Application 24196466.7, filed on 26 August 2024; and European Application 24217845.7, filed on 5 December 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a carbon nanotube separator, a surface film comprising a carbon nanotube separator, exposure equipment (such as lithography equipment, e.g., EUV utilization equipment, such as lithography equipment comprising a surface film or a carbon nanotube separator) and methods for semiconductor manufacturing processes, and the use of the surface film or carbon nanotube separator in EUV-using methods or equipment. The invention particularly relates to carbon nanotube separators comprising carbon nanotubes having preselected characteristics such as average diameter, and carbon nanotubes having surface features that inhibit or prevent the carbon nanotubes from moving relative to each other. The invention is specifically, but not exclusively, applied to EUV lithography equipment and methods, but also relates to exposure equipment (such as lithography equipment, metrology equipment, inspection equipment) for semiconductor manufacturing processes. Background Technology

[0004] A photolithography apparatus is a machine configured to apply a desired pattern onto a substrate. Photolithography apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A photolithography apparatus can project a pattern from a patterning apparatus (e.g., a mask) onto a radiation-sensitive material (resist) layer disposed on a substrate.

[0005] The minimum size of a feature that can be formed on a substrate is determined by the wavelength of radiation used by the lithography equipment to project a pattern onto the substrate. Compared to conventional lithography equipment (which may, for example, use electromagnetic radiation with a wavelength of 193 nm), lithography equipment using EUV radiation, which has electromagnetic radiation with wavelengths in the range of 4 nm to 20 nm, can be used to form smaller features on the substrate.

[0006] Photolithography equipment includes patterning apparatus (e.g., a mask or photomask). Radiation is provided to pass through or be reflected from the patterning apparatus to form an image on a substrate. A diaphragm assembly (also called a surface layer) may be provided to protect the patterning apparatus from airborne particles and other forms of contamination. Contamination on the surface of the patterning apparatus can cause manufacturing defects on the substrate.

[0007] A coating can also be provided to protect optical components other than the patterning apparatus. The coating can also be used to provide pathways for lithographic radiation between areas of a lithography apparatus that are sealed to each other. The coating can also be used as a filter (such as a spectral purity filter) or as part of a dynamic gas lock in a lithography apparatus.

[0008] The mask assembly may include a surface film that protects the patterning apparatus (e.g., a mask) from particle contamination. The surface film may be supported by a surface film frame to form the surface film assembly. The surface film may be attached to the frame, for example, by adhesive bonding or otherwise attaching the surface film boundary region to the frame. The frame may be permanently or releasably attached to the patterning apparatus.

[0009] Since the coating exists in the optical path of the EUV radiation beam, it needs to have high EUV transmittance. High EUV transmittance allows a larger proportion of the incident radiation to pass through the coating. Additionally, reducing the amount of EUV radiation absorbed by the coating can lower its operating temperature. Because transmittance depends at least in part on the coating thickness, it is desirable to provide a coating as thin as possible while maintaining reliable strength sufficient to withstand the sometimes unfavorable environment within the lithography apparatus.

[0010] Therefore, it is desirable to provide a coating material that can withstand the harsh environment of lithography equipment (especially EUV lithography equipment). In particular, it is desirable to provide a coating material that can withstand higher power than before.

[0011] Since the film is in the optical path of the photolithography equipment, if the transmittance of the film changes over time during use, it may fall outside the tolerance of the photolithography equipment and require replacement. Therefore, it is desirable to provide a film with consistent transmittance or at least a drift rate with reduced transmittance compared to the previous one during use.

[0012] A protective coating can be applied to the diaphragm material to protect it from etching within the photolithography apparatus. However, due to differences in thermal expansion between different materials, the protective coating may become damaged or separate from the diaphragm.

[0013] During nominal use, EUV utilizes pressure changes within the equipment. Additionally, due to the pulsed nature of the generated EUV radiation, the membrane diaphragm experiences very rapid heating pulses, which generate forces within the membrane diaphragm.

[0014] The present invention has been designed to address at least some of the problems identified above. Summary of the Invention

[0015] According to a first aspect of the invention, a separator is provided for use as a surface film in an exposure apparatus (such as an EUV utilization apparatus) in a semiconductor manufacturing process, the separator comprising randomly oriented uncoated carbon nanotubes having one, two, three, or each of the following: i) an average diameter of less than 5 nm and a bundle (average) diameter of less than 30 nm, wherein the Young's modulus of the separator is greater than 10 MPa; and ii) a surface feature that increases friction between the nanotubes such that the relative movement of the CNTs in the film is blocked or inhibited; iii) a hydrogen radical quencher or hydrogen radical scavenger material; and iv) a network of metal nanowires. The increased friction can be attributed to, for example, increased roughness, steric effects, CNT interbonding, or the morphology of the CNTs.

[0016] Therefore, the diaphragm may individually have one of features i), ii), iii), or iv). The diaphragm may together have any two of features i), ii), iii), or iv), such as i) and ii), i) and iii), i) and iv), ii) and iii), ii) and iv), or iii) and iv). The diaphragm may together have any three of features i), ii), iii), or iv), such as i), ii), and iii), or i), ii), and iv), or i), iii), and iv). The diaphragm may have each of i), ii), iii), and iv).

[0017] As mentioned, the environment inside exposure equipment used in semiconductor manufacturing processes (such as EUV-utilizing equipment, lithography equipment, or inspection tools) is quite harsh, where the diaphragm is affected by high temperatures (such as exceeding 600°C), EUV radiation, and hydrogen plasma. As the power of exposure equipment (such as EUV-utilizing equipment) increases, the environment will continue to become even more harsh, and therefore it is useful to provide diaphragms that can withstand the environment inside exposure equipment (such as EUV-utilizing equipment).

[0018] It has been found that CNT membranes, including those forming CNT membranes with an average diameter of less than 5 nm and a bundle average diameter of less than 30 nm, are suitable for EUV-utilizing devices. Rigidity can negatively affect the mechanical robustness, or mechanical stability, of pressure or stress sources, without being bound by scientific theory. Furthermore, it has been found that providing increased friction, such as through increased roughness of the nanotube surface, is also advantageous in stabilizing the membrane membrane. Because CNTs are very smooth structures intersecting each other in an effective point-like, zero-dimensional contact-based manner, they are prone to sliding along or across each other due to minimal friction. This, therefore, weakens the mechanical properties of membranes formed from pristine CNTs. These membranes derive their stability from entangled CNTs, which are shorter than the entire network of CNTs forming the membrane. The relatively short entanglement between CNTs allows the network to remain intact when suspended over a large area without additional support, except around the boundaries of the self-supporting (free-standing) regions of the CNT network. Because CNT meshes are subjected to thermomechanical stress during nominal use, this can cause CNTs to slide across each other, potentially leading to CNT unwinding and subsequent gaps, openings, or breaks in the mesh. Even if the failure is localized, this can result in EUV transmittance inhomogeneities exceeding desired specifications and localized losses of the film's particle-stopping function, leading to an increased defect rate count at the mask level. This invention addresses these problems by providing surface features on the CNTs that increase their effective roughness, thereby preventing or reducing the amount of sliding that CNTs can undergo relative to each other during nominal use. By limiting the sliding of CNTs relative to each other, the problem of EUV transmittance inhomogeneities is solved, and the problem of gaps is also addressed.

[0019] During use in EUV utilization equipment, carbon nanotube-based surface membranes are etched in a plasma radical environment. This etching is undesirable because it reduces the operational lifetime of the surface membrane. The etching rate in the hydrogen plasma can be reduced by heating the surface membrane (e.g., to about 700°C), which causes adsorbed hydrogen to be desorbed. It is believed, without being bound by scientific theory, that hydrogen radicals preferentially react with other hydrogen radicals to form hydrogen, rather than with the carbon structure of sp2 graphene found in carbon nanotubes. Even though heating the surface membrane is a useful way to reduce the rate of carbon etching from the membrane during use, it also provides additional thermal load on the mask protected by the surface membrane, as well as to the mask platform and other optical components. This additional thermal load can induce additional thermally induced overlap errors, which are undesirable. This disclosure provides options for extending the operational lifetime of carbon nanotube surface membranes. By providing hydrogen radical quenchers or hydrogen radical scavengers, it is possible to protect the carbon nanotubes from hydrogen plasma etching present while the EUV utilization equipment is in operation. These hydrogen radical quenchers or scavengers are used to reduce the amount of hydrogen radicals within the hydrogen plasma. These materials can be integrated with the membrane, such as as decorations on carbon nanotubes, or can be temporarily associated with the membrane, such as as materials (such as gases) adsorbed onto the membrane, which can be replenished during operation.

[0020] Alternatively, the membrane can be provided with a network of metal nanowires. Thus, the membrane can be a metal-carbon nanotube composite comprising both metal wires and carbon nanotubes. The network of the metal-carbon nanotube composite can therefore include metal wires intermixed with carbon nanotubes, thereby forming a composite network in which metal wires and CNTs are randomly mixed together. It should be understood that the wires do not necessarily have to be physically connected to other metal wires. While a coating may be provided to the carbon nanotubes, the coating would need to be thick enough to be functionally impermeable to hydrogen, which would reduce the transmittance of the membrane and could also lead to peeling, as the membrane experiences temperature changes during nominal use and the coefficients of thermal expansion of the carbon nanotubes and the coating may not be the same. By providing a metal nanowire network, the benefits of metal-assisted hydrogen recombination are achieved without requiring the metal and carbon nanotubes to have compatible coefficients of thermal expansion, and manufacturing is also simplified.

[0021] The Young's modulus can be between about 10 MPa and about 200 MPa. Regarding "about," it should be understood that this also includes values ​​of 10 MPa and 200 MPa, with deviations of ±5% or less, ±4% or less, ±3% or less, ±2% or less, or ±1% or less. Since the diaphragm is subjected to differential pressures that cause deflection during nominal use, the amount of deflection can be controlled within specifications by providing a diaphragm with a certain stiffness. However, it should be understood that since the CNT diaphragm is formed from a network of carbon nanotubes and therefore includes multiple paths for gas to pass through, differential pressures that are not fully compensated for by the porous nature of the network can still exist during nominal use.

[0022] The areal density of carbon in the membrane can be between 10 × 10⁻⁶. 15 With 500×10 15 C atoms / cm 2 Between. It has been found that such areal density is sufficient to provide CNT membranes that are strong enough to withstand EUV environments and also have EUV transmittance of over 90%.

[0023] The carbon nanotubes may have [8,3] chirality, [14,6] chirality, or mixed chirality, and optionally the mixed chirality includes at least 30% [8,3] chiral CNTs.

[0024] The etching rate of CNTs in hydrogen plasma depends at least in part on the chirality of the carbon nanotubes. Nanotubes with [8,3] chirality are etched more slowly than CNTs with the more common [6,5] chirality. It is also possible that nanotubes with [14,6] chirality are etched even more slowly in hydrogen plasma than [8,3] nanotubes. Therefore, providing CNT membranes with mixed chirality can be used to control the etching rate of CNT membranes within EUV utilization equipment. This can be useful because EUV transmittance will change during use, and by being able to control the etching rate, the rate at which EUV transmittance drifts over time can be controlled.

[0025] CNT purity can be at least 99 atomic% carbon. CNTs may be free of defectivity additives larger than 10 micrometers in size. When CNT purity is mentioned herein, it should be understood that it does not include added hydrogen scavengers and any other intentionally added metal wires or to the CNT network or surface membrane. Defectivity additives can be particles or particulate matter with EUV absorbance greater than that of CNTs. With high CNT purity of 99 atomic% carbon or greater, the risk of contamination from any additional atoms included in the CNT is reduced, and the etching rate is more predictable and uniform than when using contaminated CNTs.

[0026] The diaphragm can have an EUV transmittance greater than 90%. Since it is desirable to allow as much EUV radiation as possible to pass through the diaphragm to provide an appropriate production rate for the EUV utilization equipment and to control the heating of the diaphragm, providing a diaphragm with an EUV transmittance greater than 90% means that the temperature of the diaphragm is controlled and the production rate is maintained at an acceptable level, while still providing an effective protective diaphragm.

[0027] The diaphragm may include single-walled nanotubes, double-walled nanotubes, multi-walled nanotubes, or any combination thereof.

[0028] The carbon nanotubes may have a diameter of up to about 2 nm, up to about 2.5 nm, about 2.5 nm, about 2 nm, about 1.5 nm, or about 1 nm. In the case of slightly thicker CNTs with a diameter of about 1.5 nm or greater, they may have [14,6] chirality, which resists etching in hydrogen plasma.

[0029] CNT surface features may include defects. These defects may include one or more of the following mechanisms: a) adsorbed atoms, b) chiral Stone-Wales effect, c) two missing C atoms (in a single defect), d) monovalent defects. Alternatively or additionally, the CNT surface features may include functional groups.

[0030] Because the original CNTs are smooth, there is a low degree of friction between them, allowing them to easily slide over and across each other. By introducing surface defects, this effect is to create higher resistance to CNTs traversing each other, similar to increased friction. These surface defects can be introduced to increase friction between contacting CNTs.

[0031] Functional groups can function similarly to increase effective friction between CNTs by providing steric effects, meaning that prominent groups can physically make it more difficult for CNTs to slide past each other.

[0032] The functional groups may include hydrophobic groups, hydrophilic groups, dipole-carrying groups, or two or more of hydrophobic groups, hydrophilic groups, and dipole-carrying groups. These groups are used to increase the interaction between adjacent CNTs, thereby making it more difficult for CNTs to move or slide past each other.

[0033] The hydrophobic group may include one or more of phenyl, alkane, alkene and alkyne, and the dipole carrying group may include hydroxyl.

[0034] The surface features may include covalently bonded crosslinking groups that bond adjacent CNTs together. By providing covalently bonded crosslinking groups, the CNTs are no longer able to slide on each other. Similarly, this has the effect of increasing the effective friction between the CNTs, thereby making it more difficult for them to slide on or past each other.

[0035] The crosslinking group may be one or more of the following: 1,4-benzoquinone, 1,5-hexadiene, aryl diazonium salt, and poly(ethylene glycol) chain.

[0036] The crosslinking groups can be the reaction products of free radical polymerization of CNTs or ion beam irradiation of CNTs, or polymer coatings.

[0037] CNTs can have a non-linear morphology. In other words, the surface features can be a non-linear morphology of the CNTs. CNTs can be helical CNTs. By providing helical CNTs, they are less likely to slide over each other compared to common, essentially straight CNTs. This increases the effective friction between CNTs and makes the CNT mesh forming the diaphragm more resistant to thermomechanical forces. Additionally, these helical CNTs have greater elastic properties than non-helical CNTs and can therefore spring back after deformation. In this way, due to this structure and steric hindrance, entangled helical CNTs are actually more difficult to slide over each other, which effectively increases the friction between CNTs. This additional entanglement and limitation on the ability of CNTs to pass over each other complements the non-directional or random entanglement properties of the bundle arrangement or mesh forming the diaphragm.

[0038] The surface features may include amorphous carbon. Amorphous carbon can be deposited on CNTs to form bumps that are more difficult to slide across each other than smooth, pristine CNTs.

[0039] According to any of the foregoing technical solutions, the diaphragm in which the metal nanowire network is a random network. Random networks are useful because they are less likely to adversely affect light passing through them, such as EUV radiation. In the case of ordered networks, there is a greater probability of interaction with the light passing through them, which could lead to unwanted artifacts in the light. Furthermore, random networks are easier to fabricate.

[0040] Metal nanowires can be unoxidized. While oxidized metal surfaces can recombine hydrogen radicals, unoxidized metal surfaces have a higher surface recombination efficiency. Therefore, unoxidized surfaces are more effective at recombinating hydrogen radicals, meaning that fewer metal nanowires may be needed and / or the recombination rate may be higher, resulting in a reduced amount of hydrogen radicals that can be used to etch carbon nanotubes.

[0041] Metal nanowires may include at least one metal with high hydrogen recombination efficiency. Metal nanowires may include rhodium, platinum, or combinations thereof. Using a metal with high hydrogen recombination efficiency requires less metal, which contributes to manufacturing cost and difficulty, and / or results in a high rate of hydrogen radical recombination.

[0042] Metal nanowires can have a diameter smaller than that of carbon nanotubes. Metal nanowires can have a diameter equal to that of carbon nanotubes. Metal nanowires can have a diameter larger than that of carbon nanotubes. Preferably, the diameter of the metal wire is as small as possible. Metal nanowires can have an average diameter smaller than the average diameter of carbon nanotubes or carbon nanotube bundles. Metal nanowires can have an average diameter smaller than the thickness of the CNT surface membrane / septum. A smaller diameter means that the metal nanowires absorb less EUV radiation. Furthermore, since hydrogen radical recombination on the metal is primarily a surface phenomenon, thinner wires mean a higher effective surface area for hydrogen radical recombination compared to thicker wires, even with the same total metal mass. Metal nanowires can have a diameter of 30 nm or less. Nanowires can have a diameter of about 10 nm to about 20 nm.

[0043] Nanowires can be electrospun nanowires. Electrospun metal wires can produce wires with very small diameters and are also a fast and consistent process. Furthermore, metal nanowires are completely filled with metallic material, meaning they do not have the hollow core found in carbon nanotubes.

[0044] Nanowires can be interwoven with carbon nanotubes. Therefore, interweaving metal nanowires with carbon nanotubes allows the metal nanowires to protect the carbon nanotubes more effectively compared to a membrane consisting of layers of metal nanowires and carbon nanotubes. The term "interweaving" is not intended to specify the presence of a particular weaving pattern or weaving steps during the manufacturing process, but simply to indicate that the metal nanowires and carbon nanotubes are combined into a composite mesh. For example, the metal nanowires and carbon nanotubes can be mixed or woven together in a wet or dry mixing process before forming the surface membrane / septum.

[0045] The hydrogen scavenger or hydrogen quencher material is an alkyne, optionally wherein the hydrogen scavenger or hydrogen quencher material is disposed on a carbon nanotube. The alkyne comprises a triple bond between two carbon atoms and is capable of readily reacting with hydrogen radicals. The alkyne is capable of reacting rapidly with hydrogen radicals. Because the reaction rate of alkyne with hydrogen radicals is shorter than the lifetime of chemisorbed or physisorbed hydrogen radicals, the reaction with alkyne can effectively protect the carbon nanotubes by overcoming the reaction of the carbon nanotubes with hydrogen radicals. The alkyne may be provided in the form of a layer (such as a monolayer) adsorbed onto the membrane. Thus, the alkyne can associate via intermolecular forces (such as van der Waals forces). The alkyne layer can be renewed by providing additional alkyne material during operation. The alkyne can be chemically bonded to the carbon nanotube, which may be referred to as alkyne-decorated carbon nanotubes. Alkynes formed from carbon and hydrogen have good EUV transmittance and therefore do not adversely affect the amount of EUV radiation that can pass through them. Furthermore, acetylene and propyne have low boiling points and are therefore gaseous at the operating temperatures of machines using EUV. Consequently, there is no risk of them depositing inside the machine (such as on optical components like mirrors). Moreover, the reaction products of alkynes with hydrogen radicals have even lower boiling points than the alkynes themselves, so similarly there is no risk of reaction product deposition. For example, acetylene has a boiling point of -84°C, and its reaction product with hydrogen radicals, ethane, has a boiling point of -107°C.

[0046] According to an embodiment of the first aspect, a separator is provided for use as a surface film in an exposure apparatus (such as an EUV utilization apparatus) for semiconductor manufacturing. The separator includes a core comprising randomly oriented carbon nanotubes disposed between a first non-conformal top layer and a second non-conformal bottom layer. The top layer and / or the bottom layer may be a separator. The core may be a membrane.

[0047] Therefore, the separator is a multilayer separator comprising a carbon nanotube layer sandwiched between two non-conformal layers. The non-conformal layers are preferably substantially planar, such as planar separators. It should be understood that the layers may not be perfectly flat due to the inherent structure of the layer material and manufacturing tolerances. It has been found that, for a specific value of conductivity of the non-conformal separator, providing a non-conformal layer on either side of the carbon nanotube core can increase the overall emissivity of the separator to approximately 72%. Without the non-conformal layer, the emissivity is less than 10%. Higher emissivity means that the separator can withstand higher power loads than otherwise possible, or can operate at lower temperatures under the same power load than a separator without two facets.

[0048] During operation, the membrane is etched by hydrogen plasma. Without being bound by scientific theory, it is believed that etching is caused by the breaking of carbon-carbon bonds within the carbon nanotubes, followed by hydrogen passivation of dangling carbon bonds. Over time, carbon is released from the carbon nanotubes as volatile hydrocarbons. While etching could potentially be reduced or eliminated by releasing hydrogen from the membrane to prevent any dangling bonds from being passivated, the breaking of carbon-carbon bonds still results in a loss of continuous mechanical prestress. Therefore, although etching can be addressed, the SP2 hexagonal crystalline CNT structure transforms into SP3 amorphous carbon over time. In practice, it has been observed that the yield strength of the carbon nanotube membrane decreases by 50% after 1000 wafer exposures equivalent in plasma at approximately 5 eV H-ion energy, and this decrease increases to 90% after 2000 wafer exposures equivalent, representing a 90% reduction in yield strength. While coating the CNTs themselves could potentially protect them, this comes at the cost of reduced EUV transmittance and increased flare, both of which are undesirable. Reduced transmittance means a larger proportion of the energy falling on such a membrane is absorbed, leading to higher operating temperatures. Although emissivity could be increased to counteract this, adding a conformal metallic coating could result in even lower EUV transmittance and therefore even greater heating. Furthermore, due to the difference in thermal expansion coefficients between the carbon nanotubes and the conformal coating, the coating could detach from the carbon nanotubes during nominal use.

[0049] The planar encapsulation of the carbon nanotube core according to this disclosure provides increased emissivity, which significantly improves power capability, and also reduces or eliminates mechanical degradation. Compared with uncoated carbon nanotubes, planar encapsulation also reduces EUV spotting and out-of-bounds scattering, and also reduces or removes geometric EUV transmittance loss caused by membrane porosity.

[0050] When electromagnetic waves with wavelengths greater than approximately 10 micrometers are incident on an absorbing material, the resulting reflection, transmission, and absorption lead to increased absorption. For carbon nanotubes, reflectivity and absorptivity are very low, while transmittance is very high. It has been shown that for wavelengths greater than 10 micrometers, the solution to Maxwell's equations simplifies, and reflection, transmission, and absorption exhibit a characteristic trend as a function of the parameter f, which covers any absorbing metallic material at that wavelength, such that absorption reaches its maximum value of 50% at f = 2. The parameter f represents the product of the absorber thickness s and the conductivity σ, with a proportionality constant of 120π.

[0051] Placing a dielectric layer with a refractive index squared (n²) adjacent to an absorber alters the theoretical maximum absorption of radiation. Placing two infrared absorber layers, separated by vacuum, results in a theoretical maximum absorption of 83% for radiation exceeding 10 micrometers, significantly higher than the 50% of a single absorber layer, contingent on the layer combination factor f reaching a value of f = √2. When a dielectric is placed between two absorber layers, the maximum absorption changes from 83% to a lower value, but remains above 50%. For example, with a refractive index squared of 2.5, the maximum absorption drops to 70%.

[0052] For the case of two metal absorber layers separated by a vacuum, the square of the refractive index is 1, f = √2, and f = 120πσ(s1 + s2), where s1 and s2 are the thicknesses of the two absorber layers. This equation can possibly be rearranged as:

[0053]

[0054] It has been found that for specific values ​​of conductivity and the number of electrons per atom contributing to conductivity, this trend shifts from wavelengths greater than 10 micrometers to lower values, causing the wavelengths to shift into the region of maximum thermal emissivity provided by Wien's displacement law. This is the case where Kirchoff's law states that absorptivity equals emissivity in thermal equilibrium. Therefore, if the maximum absorptivity for shorter wavelengths increases, the emissivity also increases. In this way, not only does the emissivity of far-infrared radiation from the surface membrane increase, but lower wavelengths are also effectively radiated. It should be understood that the emissivity of all radiation at certain wavelengths will depend on the materials of the top and / or bottom layers. For example, it has been found that when using a conductivity of 2.76 MJ·kg⁻¹, the emissivity of all radiation at certain wavelengths will depend on the materials of the top and / or bottom layers. -1 ·m -1 When bilayer graphene is used as both the top and bottom layers, the emissivity of all radiation with wavelengths of 4.0 micrometers or greater is enhanced, allowing the film according to this disclosure, heated to approximately 450°C, to be effectively radiatively cooled across all its available wavelengths. For additional examples, the molybdenum layer will provide emissivity for all radiation with wavelengths of 1.7 micrometers or greater, rhenium for all radiation with wavelengths of 4.4 micrometers or greater, and beryllium for all radiation with wavelengths of 8.8 micrometers or greater. The electrical conductivity of one or both of the top and bottom layers can be from approximately 1 to approximately 6 MJ·kg⁻¹. -1 ·m -1 .

[0055] The heated membranes are also capable of radiation, and although this may be slightly less efficient, they still exhibit significantly higher emissivity than existing carbon nanotube films. Thus, it has been unexpectedly realized that the addition of non-conformal top and bottom layers actually significantly increases emissivity. Although there is no vacuum between the top and bottom layers, the presence of the carbon nanotube core and its significant porosity still allows for this advantage. If the porosity of the carbon nanotube layers is assumed to be 50%, then n 2 The value of n (where n is the refractive index) in vacuum is n 2 value (n) 2 =1) and the n of the densely packed CNT layers 2 value (n) 2 Somewhere between 1 and 4. Specifically, for composite materials such as porous CNT membranes in a vacuum, using the Maxwell-Garnett effective medium method, n can be estimated as follows: 2 value:

[0056]

[0057] Where p = 0.5, and the porosity is assumed to be 50% (50% vacuum and 50% CNT). The effective refractive index square is approximately 2.2, which results in a maximum absorption of approximately 72%.

[0058] This effect is achieved using the Hagen-Rubens equations for the bilayer system according to this disclosure, which relate the electronic relaxation time τ of the metal to its conductivity σ, wherein:

[0059]

[0060] Where m e is the mass of the electron, e is the charge of the electron, and n is the electron density.

[0061] With a small τ, the incident wave is in phase with the electron density current for higher frequencies and longer wavelengths. For most metallic materials, this requires the Hagen-Rubens relation to remain effective at wavelengths of 10 micrometers or higher. The transition angular frequency at which the Hagen-Rubens relation holds is given by the following equation:

[0062]

[0063] The relationship between angular frequency and wavelength is given by the following formula:

[0064] Where c is the speed of light in a vacuum.

[0065] This leads to the following equation:

[0066]

[0067] Based on this equation, it is possible to determine which materials are allowed to... The values ​​are shifted to values ​​below 10 micrometers. For example, rhenium (Re), beryllium (Be), molybdenum (Mo), and graphene all provide thresholds below 10 micrometers. Thus, these materials allow membranes comprising sheets of these materials to be thermally cooled while radiating to their maximum extent in the spectral region defined by Planck's emission law and Wien's shift law.

[0068] For example, when the top and bottom layers include graphene membranes, this provides approximately 4.0 micrometers. A suitable f-value and a specific value enhance the maximum absorption. Graphene exhibits absorption values ​​ranging from approximately 2 to 200 × 10⁻⁶. 5 Sm -1 The high electrical conductivity is achieved. With graphene included in both the top and bottom layers, a value of f = 2 can be provided with a thickness of approximately 0.68 nm, which can be achieved via a graphene bilayer. This would result in a membrane with a maximum absorption of approximately 72% for light up to 4.0 micrometers. It is noteworthy that the thickness of the spacing between the two layers, or the dielectric spacer between the two layers, is not included in the derived equations and is therefore not a limiting consideration in practice. Such a membrane would exhibit maximum emissivity at approximately 450 °C.

[0069] The top and bottom layers do not conform to the CNT core morphology, but are essentially flat planar layers.

[0070] The top and bottom layers can be the same. The top and bottom layers can be different.

[0071] One or both of the top and bottom layers may include 2D materials. The 2D materials may be selected from one or more carbon-based, silicon-based, and boron-based 2D materials. The 2D materials may include graphene, silicene, TMDS (tetramethyldisiloxane), black phosphorus, carbon nitride, germanene, boronene, tinene, arsenene, aluminene, antimonyene, or bismuthene.

[0072] One or both of the top and bottom layers may include molybdenum, ruthenium, beryllium, or rhenium. Molybdenum, ruthenium, beryllium, or rhenium may be disposed on top of the 2D material to improve emissivity. As discussed, these materials have been found to have low emission thresholds when configured as two separate layers and are therefore capable of effectively radiating thermal radiation to provide cooling.

[0073] The carbon nanotubes in the core can be carbon nanotubes according to the first aspect of this disclosure.

[0074] Each and both of the top and bottom layers may include an additional conductive layer. It should be understood that the top and / or bottom layers may already be conductive, but additional conductive layers may be added. Therefore, the top and / or bottom layers may include two conductive layers or one non-conductive layer and one conductive layer. It should be understood that the top and bottom layers are not necessarily required to be the outermost layers, as these top and bottom layers may have additional layers disposed thereon. Top and bottom are used to indicate two opposite sides of the core membrane or separator.

[0075] One or both of the top and bottom layers may be continuous. One or both of the top and bottom layers may be at least partially formed by patches. Optionally, the patches may be separated by gaps of 4 micrometers (μm) or less.

[0076] One or both of the top and bottom layers can be double-layered.

[0077] One or both of the top and bottom layers may be provided with a capping layer, optionally comprising one or more of alumina, yttrium oxide, and yttrium silicon oxide. The capping layer is selected to protect the base layer from etching by hydrogen plasma, thereby extending the lifetime of the separator.

[0078] The diaphragm can have an emissivity greater than 50%. As discussed, the diaphragm of this disclosure is constructed such that it has an emissivity greater than the theoretical maximum emissivity (i.e., 50%) of a single-layer diaphragm. Therefore, a single-layer diaphragm cannot achieve these theoretical emissivity. This is achieved by providing two layers spaced apart from each other.

[0079] Also provided is a method for manufacturing a diaphragm for an exposure apparatus (such as an EUV utilization apparatus) used in semiconductor manufacturing, the method comprising the steps of: i) providing a core film comprising a plurality of randomly oriented carbon nanotubes having a top surface and a bottom surface, and ii) providing substantially planar layers on the top surface and the bottom surface.

[0080] The method may include depositing silicon oxide on the core membrane prior to step ii). In this way, the silicon oxide can hold the carbon nanotubes in place while the separator is being manufactured.

[0081] The method may also include removing material from the top and / or bottom surfaces prior to step ii) to provide planar top and / or bottom surfaces. It is desirable to make the final diaphragm planar, and therefore by removing material from the top and bottom surfaces, it is possible to provide planar surfaces on which top and bottom layer materials can be provided.

[0082] The method may include providing a substantially planar layer on the top surface of the plane and a substantially planar layer on the bottom surface of the plane.

[0083] The method may also include removing any support layer from the diaphragm. It should be understood that the top and bottom layers may be fragile due to their thinness and the materials used to manufacture them. Therefore, the top and / or bottom layers may be disposed on a support layer, which can then be removed.

[0084] The method may also include providing a capping layer on one or both of the planar layers on the top surface and / or the planar layers on the bottom surface. As discussed, the capping layer is used to protect the base layer from hydrogen plasma during use.

[0085] The method may also include etching the silicon oxide deposited on the core film. Removing the silicon oxide deposited on the core film is useful because it is desirable to provide a membrane with high transmittance, as removal reduces the amount of material that the laser beam must pass through in nominal use, and thus increases the transmittance of the membrane.

[0086] According to a second aspect of this disclosure, a membrane for an EUV utilization device is provided, the membrane comprising a diaphragm according to any of the foregoing technical solutions and a support frame for supporting the diaphragm.

[0087] According to a third aspect of this disclosure, an apparatus for extending the operational life of a membrane diaphragm is provided, the apparatus being configured to provide a hydrogen radical quencher or hydrogen radical scavenger material to the membrane diaphragm.

[0088] As described, the carbon nanotube-based membrane diaphragm may include a hydrogen radical quencher or hydrogen radical scavenger material. This may be a material separate from the membrane diaphragm, such as an alkyne gas, which is provided to the diaphragm to preferentially react with hydrogen radicals that would otherwise etch carbon from the carbon nanotubes.

[0089] The equipment may include a metering feeder configured to guide hydrogen radical quencher or hydrogen radical scavenger material toward the membrane diaphragm. The metering feeder may be a conduit having an outlet for supplying quencher or scavenger material to the diaphragm.

[0090] Hydrogen radical quencher or hydrogen radical scavenger material may include alkynes, optionally wherein the alkynes are acetylene, propyne or a combination thereof.

[0091] The equipment may include a controller configured to control the supply of hydrogen radical quencher or scavenger material. The controller may be configured to control the rate at which the quencher / scavenger material is supplied. For example, during operation, the amount of hydrogen radicals in the atmosphere in which the membrane diaphragm is located will vary depending on how the EUV utilization equipment is operated. In the presence of a larger amount of hydrogen radicals, the rate at which the quencher / scavenger material is supplied can be increased. Similarly, when a reduced amount of hydrogen radicals is present, the rate at which the quencher / scavenger material is supplied can be decreased.

[0092] The device can be configured to provide hydrogen radical quencher or hydrogen radical scavenger material to one or both of the front and back sides of the membrane. While the front side of the membrane is likely to be etched by the largest amount of hydrogen radicals, the back side may also be etched. Therefore, the device can be configured to provide protective quencher / scavenger material to either or both sides.

[0093] The device can be configured to supply hydrogen radical quencher or scavenger material to the membrane at a rate sufficient to provide a monolayer every 5 seconds or less, every 4 seconds or less, every 3 seconds or less, every 2 seconds or less, or every second or less. Because the quencher / scavenger material will react with hydrogen radicals or will otherwise be released from the membrane during nominal use, it may be necessary to replace the quencher / scavenger material to provide continuous protection for the membrane.

[0094] The device can be configured to provide hydrogen radical quencher or hydrogen radical scavenger materials at pressures of 0.10 mPa or less, 0.09 mPa or less, 0.08 mPa or less, 0.07 mPa or less, 0.06 mPa or less, 0.05 mPa or less, 0.04 mPa or less, 0.03 mPa or less, 0.02 mPa or less, or 0.01 mPa or less.

[0095] According to a fourth aspect of this disclosure, an EUV utilization device is provided, comprising a diaphragm, apparatus, or film according to any of the foregoing technical solutions, wherein optionally the EUV utilization device is an EUV lithography apparatus or an EUV inspection tool.

[0096] According to a fifth aspect of this disclosure, a method for manufacturing a diaphragm for an EUV utilization device is provided, the method comprising the steps of: i) providing surface features to a plurality of CNTs to prevent the CNTs from sliding over each other when formed into a CNT diaphragm, and ii) forming a CNT diaphragm of the CNTs.

[0097] According to a sixth aspect of this disclosure, a method for extending the operational life of a carbon nanotube-based surface membrane is provided, the method comprising one or both of the following: i) providing a hydrogen radical quencher or hydrogen radical scavenger material to the surface membrane; and ii) providing a metal nanowire network associated with the surface membrane.

[0098] As described above, it may extend the operational life of the CNT surface membrane, but by providing one or both of the hydrogen radical quencher / scavenger materials and the metal nanowire network, which alone or in combination are used to reduce the amount of hydrogen radicals capable of etching carbon nanotubes, whether by reacting with hydrogen radicals or by catalyzing the recombination of hydrogen radicals into hydrogen.

[0099] The method may include providing an alkyne to the membrane as a hydrogen radical quencher or hydrogen radical scavenger material, wherein the alkyne optionally includes acetylene, propyne, or a combination thereof.

[0100] The method may include providing a hydrogen radical quencher or hydrogen radical scavenger material to one or both of the front and back sides of the membrane.

[0101] Hydrogen radical quencher or scavenger material is provided in gaseous form. By providing the quencher / scavenger in gaseous form, the gas can diffuse and provide protection over a larger area of ​​the surface membrane. Furthermore, the gas is not easily condensed or otherwise deposited, thus avoiding surface contamination.

[0102] The availability of hydrogen radical quencher or scavenger materials can be controlled by the amount or concentration of hydrogen radicals generated during use. Therefore, depending on the amount of hydrogen radicals that need to be removed, more or less quencher / scavenger material can be provided.

[0103] The method may include providing a network of metal nanowires interwoven with carbon nanotubes. As described, the metal nanowire network can be used to protect carbon nanotubes by causing hydrogen radicals to recombine.

[0104] According to the seventh aspect of this disclosure, there are uses in a diaphragm according to the first aspect, a membrane according to the second aspect, an apparatus according to the third aspect, an EUV utilization apparatus according to the fourth aspect, a method according to the fifth aspect, or a method according to the sixth aspect in a method or apparatus for using EUV.

[0105] According to the eighth aspect of this disclosure, alkynes are provided for use in extending the operational life of carbon nanotube surface membranes.

[0106] As described, alkynes (such as acetylene or propyne) are provided to carbon nanotube-based membranes to extend the membrane's lifetime by reacting with hydrogen radicals, thereby serving as a hydrogen radical scavenger or quencher material.

[0107] According to a ninth aspect of this disclosure, metal nanowires are provided for use in extending the operational life of carbon nanotube surface membranes. As in the eighth aspect, the metal nanowires are used to protect carbon nanotubes from etching by hydrogen free radicals by catalyzing the recombination of hydrogen free radicals into hydrogen, thus preventing hydrogen free radicals from etching carbon from the carbon nanotubes.

[0108] It should be understood that the features described with respect to one embodiment can be combined with any features described with respect to another embodiment, and all such combinations are expressly contemplated and disclosed herein. Attached Figure Description

[0109] Embodiments of the invention will now be described by way of example only with reference to the accompanying illustrative drawings, in which corresponding reference numerals indicate corresponding parts, and in the drawings:

[0110] Figure 1 A photolithography apparatus according to an embodiment of the present invention;

[0111] Figures 2A and 2B depict the deflection or flexure of the diaphragm according to the present disclosure during pumping at different pressure differentials and flow rates.

[0112] Figure 3 The membrane assembly is schematically depicted in a cross-sectional view;

[0113] Figure 4 A schematic depiction of the composite membrane diaphragm according to the present disclosure;

[0114] Figure 5 A schematic depiction of the device according to this disclosure;

[0115] Figures 6A and 6B are schematic depictions of a surface film including a carbon nanotube layer and a surface film including a carbon nanotube layer comprising a top layer and a bottom layer, respectively.

[0116] Figures 7A and 7B are schematic depictions of a double-layer membrane including a vacuum and a double-layer membrane including a carbon nanotube core, respectively.

[0117] Figures 8A to 8J are schematic depictions of the manufacturing process; and

[0118] Figure 9 This is a schematic depiction of step f shown in Figure 8F.

[0119] The features and advantages of the invention will become apparent from the following detailed description set forth in conjunction with the accompanying drawings, in which similar reference numerals consistently identify corresponding elements. In the drawings, the same reference numerals generally indicate identical, functionally similar, and / or structurally similar elements. Detailed Implementation

[0120] Figure 1A lithography system according to one aspect of this disclosure is illustrated, comprising a surface film 15 including a carbon nanotube membrane. The lithography system includes a radiation source SO and a lithography apparatus LA. The radiation source SO is configured to generate an extreme ultraviolet (EUV) radiation beam B. The lithography apparatus LA includes an irradiation system IL, a support structure MT configured to support a pattern forming apparatus MA (e.g., a mask), a projection system PS, and a substrate stage WT configured to support a substrate W. The irradiation system IL is configured to adjust the radiation beam B before it is incident on the pattern forming apparatus MA. The projection system is configured to project the radiation beam B (now patterned by the mask MA) onto the substrate W. The substrate W may include a previously formed pattern. In such a case, the lithography apparatus aligns the patterned radiation beam B with the pattern previously formed on the substrate W. In this embodiment, the surface film 15 is drawn in the path of radiation and protects the pattern forming apparatus MA. It should be understood that the surface film 15 can be located in any desired position and can be used to protect any of the mirrors in the lithography apparatus. The surface film 15 may be part of a spectral purity filter.

[0121] The radiation source SO, the irradiation system IL, and the projection system PS can all be constructed and arranged to isolate them from the external environment. A gas at a pressure below atmospheric pressure (e.g., hydrogen) can be placed in the radiation source SO. A vacuum can be placed in the irradiation system IL and / or the projection system PS. A small amount of gas at a pressure far below atmospheric pressure (e.g., hydrogen) can be placed in the irradiation system IL and / or the projection system PS.

[0122] Figure 1 The radiation source SO shown is of the type that can be referred to as a laser-generated plasma (LPP) source. A laser, such as a CO2 laser, is arranged to deposit energy via a laser beam onto a fuel such as tin (Sn) supplied from a fuel emitter. Although tin is mentioned in the following description, any suitable fuel can be used. The fuel can be, for example, in liquid form and can be, for example, a metal or alloy. The fuel emitter can include a nozzle configured to guide tin, for example, in the form of droplets, along a trajectory toward the plasma-forming region. The laser beam is incident on the tin at the plasma-forming region. The laser energy deposited into the tin generates plasma at the plasma-forming region. Radiation, including EUV radiation, is emitted from the plasma during the de-excitation and recombination of ions in the plasma.

[0123] EUV radiation is collected and focused by a near-normal incident radiation collector (sometimes more generally referred to as a normal incident radiation collector). The collector may have a multi-layered structure arranged to reflect EUV radiation (e.g., EUV radiation with a desired wavelength such as 13.5 nm). The collector may have an elliptical configuration with two elliptical foci. The first focal point may be located at the plasma formation region, and the second focal point may be located at the intermediate focal point, as discussed below.

[0124] The laser can be separated from the radiation source SO. In such a case, the laser beam can be transmitted from the laser to the radiation source SO by means of a beam delivery system (not shown) including, for example, suitable directional mirrors and / or beam expanders and / or other optical devices. The laser and the radiation source SO can be considered together as a radiation system.

[0125] Radiation reflected by the collector forms a radiation beam B. Radiation beam B is focused at a point to form an image of the plasma formation region, which serves as a virtual radiation source for irradiating system IL. The point where radiation beam B is focused can be referred to as the intermediate focal point. The radiation source SO is arranged such that the intermediate focal point is located at or near an opening in the enclosure structure of the radiation source.

[0126] A radiation beam B is transmitted from a radiation source SO to an irradiation system IL, which is configured to modulate the radiation beam. The irradiation system IL may include a faceted field mirror assembly 10 and a faceted pupil mirror assembly 11. Together, the faceted field mirror assembly 10 and the faceted pupil mirror assembly 11 provide a radiation beam B with a desired cross-sectional shape and a desired angular distribution. The radiation beam B is transmitted from the irradiation system IL and incident on a pattern forming apparatus MA held by a support structure MT. The pattern forming apparatus MA reflects and patternes the radiation beam B. In addition to or in place of the faceted field mirror assembly 10 and the faceted pupil mirror assembly 11, the irradiation system IL may also include other mirrors or devices.

[0127] After reflection from the patterning apparatus MA, the patterned radiation beam B enters the projection system PS. The projection system includes multiple mirrors 13 and 14 configured to project the radiation beam B onto a substrate W held by a substrate stage WT. The projection system PS can apply a reduction factor to the radiation beam to form an image with features smaller than the corresponding features on the patterning apparatus MA. For example, a reduction factor of 4 can be applied. Although in Figure 1 The projection system PS has two mirrors 13 and 14, but the projection system can include any number of mirrors (e.g., six mirrors).

[0128] Figure 1The radiation source SO shown may include components not illustrated. For example, a spectral filter may be incorporated into the radiation source. This spectral filter can substantially transmit EUV radiation but substantially block radiation of other wavelengths, such as infrared radiation.

[0129] In an embodiment, the diaphragm assembly 15 is the surface film of a patterning apparatus MA for EUV lithography. The diaphragm assembly 15 of the present invention can be used for dynamic gas locks, as a surface film, or for another purpose. In an embodiment, the diaphragm assembly 15 includes a diaphragm formed of at least one diaphragm layer configured to transmit at least 90% of incident EUV radiation. To ensure maximum EUV transmission and minimize the impact on imaging performance, the diaphragm is preferably supported only at the boundaries.

[0130] If the pattern forming apparatus MA is not protected, contamination may require cleaning or disposal of the MA. Cleaning the MA interrupts valuable manufacturing time, while discarding it is costly. Replacing the MA also interrupts valuable manufacturing time.

[0131] Figure 2a and Figure 2b The sag of the CNT membrane diaphragm varies with pretension and EUV transmittance. To avoid exceeding specifications, the deflection needs to be less than just over 1000 micrometers, which is depicted in the light gray area in the upper right part of the graph. The exact curve depends on the load-locking pumping characteristics, which nominally occur at approximately 9 kPa. Figure 2a However, the surface membrane diaphragm is preferably capable of withstanding a pressure difference of 20 kPa. The graph depicts a surface membrane diaphragm with a Young's modulus of 100 MPa and a flow resistivity of 8 Pa / sccm.

[0132] Stone-Wales defects significantly increase the required separation force, with a larger percentage of Stone-Wales defects contributing to this increase. For example, the separation force of defect-free CNTs is generally independent of CNT length, while the introduction of 5% vacancies causes the separation force to increase with increasing CNT length. Stone-Wales defects significantly increase the separation force between CNTs, resulting in a higher separation force than the original CNTs across all CNT lengths. When comparing CNTs with Stone-Wales defects to original CNTs, the difference in separation force becomes increasingly larger with increasing CNT length. CNTs with 5% Stone-Wales defects require greater separation force than CNTs with 2.5% Stone-Wales defects. At a CNT length of approximately 10 nm, CNTs with 5% Stone-Wales defects have approximately twice the separation force of original CNTs of the same length. At a CNT length of approximately 50 nm, CNTs with 5% Stone-Wales defects have approximately seven times the separation force compared to original CNTs. At a CNT length of 100 nm, CNTs with 5% Stone-Wales defects exhibit approximately ten times greater separation force compared to pristine CNTs. Furthermore, increasing the length of CNTs with these defects increases the force, while simply increasing the length of the pristine CNTs has a very small (if any) effect on the desired separation force. Thus, friction is largely independent of the stacking length of the pristine CNTs.

[0133] Figure 3 The diagram schematically illustrates an in-situ film assembly 15 on a pattern forming apparatus MA. The film assembly includes a film 19 held in place by a film frame 17 according to an embodiment of the present disclosure. The film can be attached to the frame 17, for example, by adhesive bonding or otherwise, by attaching a film boundary region (not shown) to the frame 17. The frame 17 can be permanently or releasably attached to the pattern forming apparatus MA.

[0134] The surface coating 19 is disposed in the path of both the incident radiation beam B and the reflected patterned radiation beam B'. The radiation beam passes through the surface coating 19 twice. The surface coating 19 substantially transmits EUV radiation (but it absorbs a small amount of EUV radiation). The surface coating 19 serves to protect the patterning apparatus MA from particle contamination. Although efforts can be made to maintain a clean environment inside the lithography apparatus LA, particles can still be present inside the lithography apparatus LA. In the absence of the surface coating 19, particles can deposit onto the patterning apparatus MA. Particles on the patterning apparatus MA in the focal plane of the lithography apparatus can adversely affect the pattern imparted to the radiation beam B and thus affect the pattern transferred to the substrate W. The surface coating 19 provides a barrier between the patterning apparatus MA in the lithography apparatus LA and the environment to prevent particle deposition on the patterning apparatus MA.

[0135] In use, the surface film 19 of the surface film assembly 15 is positioned at a distance from the patterning apparatus MA via the surface film frame 17. This distance is sufficient to separate particles (e.g., particle 22) incident on the surface of the film from the focal plane of the radiation beam B. The distance between the surface film 19 and the patterning apparatus MA reduces the extent to which any particles on the surface of the surface film 19 impart a pattern to the radiation beam B. Particles present in the radiation beam B but not at the focal plane of the radiation beam B (i.e., not at the surface of the patterning apparatus MA) will not be focused onto the surface of the substrate W. In the absence of other considerations, it may be desirable to position the film at a considerable distance from the patterning apparatus MA. However, in practice, the space available in the lithography apparatus LA to house the surface film assembly 15 is limited by the presence of other components.

[0136] Figure 4 This is a schematic depiction of a composite membrane 15 according to the present disclosure. The composite membrane 15 includes interwoven or entangled carbon nanotubes 23 and metal nanowires 24. As depicted, the metal nanowires 24 are capable of catalyzing the recombination of hydrogen radicals into hydrogen, thereby protecting the carbon nanotubes 23 from etching.

[0137] Figure 4This is a schematic depiction of the apparatus according to the present disclosure. As depicted, a support structure MT is present, which may be a mask platform, and the mask platform support may be a mask patterning apparatus MA. A surface membrane 15, which may be a surface membrane diaphragm according to the present disclosure or any other type of carbon nanotube-based surface membrane diaphragm, is disposed in the path of the radiation beam B and is positioned to separate contaminants on the surface membrane diaphragm 15 such that the contaminants do not impart a pattern on the radiation beam B. A metering feeder 25 is provided, which is fluidly connected to a supplyer 26 via a line 27. The metering feeder 25 is configured to supply a hydrogen radical scavenger or quencher material, such as an alkyne (e.g., acetylene), to the surface membrane diaphragm 15. This supply is depicted as a spray 28, but it should be understood that the gas may diffuse into the environment surrounding the surface membrane diaphragm 15. Although only one metering feeder 25 is depicted, it should be understood that more than one metering feeder may be present. The positioning of the metering feeder 25 is also illustrative, and the metering feeder 25 can be positioned wherever there is available space and it can supply quench / remove material to the surface diaphragm. Since the hydrogen etch rate is maximized just outside the spot of the surface diaphragm 15 through which the radiation beam B passes in nominal use, the metering feeder 25 can be configured to supply quench / remove material to the area of ​​the surface diaphragm 15 subjected to the maximum etch rate in nominal use.

[0138] In use, radiation beam B is passed through the surface membrane 15, thereby heating the surface membrane 15. Radiation beam B also generates a hydrogen plasma, which includes hydrogen ions and free radicals that can etch carbon from the carbon nanotubes of the surface membrane 15. It is believed that hydrogen adsorption onto the surface of the membrane is necessary to induce etching, and the high temperatures observed in the region of the surface membrane 15 through which radiation beam B passes in nominal use cause any adsorbed hydrogen to desorb and release. Outside such regions, the temperature is not high enough for hydrogen desorption and release, but a hydrogen plasma environment still exists, resulting in the highest etching rate. A metering feeder 25 provides alkynes, such as acetylene, that react rapidly with hydrogen free radicals, thereby preventing them from etching the carbon nanotubes. As mentioned, acetylene can be supplied to the region of fastest etching to extend the operational life of the surface membrane 15.

[0139] Figure 6a and Figure 6b It is a schematic depiction of the surface film including the carbon nanotube layer. Figure 6a A surface film 20A is depicted, comprising a carbon nanotube core 21A supported by a framework 22A. The surface film 20A does not include a top layer and a bottom layer, and therefore has a theoretical maximum IR absorption / emission rate of 50%. Figure 6b The image depicts a surface film 20B comprising a carbon nanotube core having a top layer 21B and a bottom layer 23B having a capping layer 21B on both sides. (Example) Figure 6bAs shown, the surface membrane includes a layer of carbon nanotubes sandwiched between two planar layers. As described, the presence of the top and bottom planar layers and the space therebetween containing the carbon nanotubes serves to improve the emissivity of the surface membrane and thus provide improved thermal control.

[0140] Figure 7a and Figure 7b These are schematic depictions of a double-layered membrane including a vacuum and a double-layered membrane including a carbon nanotube core, respectively. First, turn to... Figure 7a This describes a scenario that would provide the theoretically highest absorption, where a vacuum exists between the two layers. This would provide 83% of the maximum absorption. Figure 7b An embodiment is depicted in which the core includes carbon nanotubes. Although the presence of carbon nanotubes reduces the theoretical maximum absorption to 72%, the carbon nanotubes serve to support the top and bottom layers and provide strength to the surface membrane. Figure 7b The embodiments depict graphene bilayers on the top and bottom of the CNT core.

[0141] Figures 8a to 8j are schematic depictions of a process for manufacturing a film according to the present disclosure. In step A, a carbon nanotube core is provided. The carbon nanotube core is supported by a framework. In step B, silicon oxide is provided on the carbon nanotube core. The silicon oxide can be provided by any suitable means, such as, for example, atomic layer deposition. In step C, additional silicon oxide is provided. It should be understood that step C may not be necessary. It should also be understood that step B can continue until the desired amount of silicon oxide has been provided. In step D, the top side can be etched to provide a plane, and in step E, the bottom side can be etched to provide a plane. Steps D and E can be performed in any order and can be performed simultaneously. Etching can be achieved by any suitable means, such as, for example, reactive ion etching. In step F, a top layer and a bottom layer are added to the top and bottom surfaces of the current plane. The top and bottom layers can be, for example, graphene layers. The graphene layers can be graphene bilayers. In step G, the support layers for supporting the top and bottom layers of the plane are removed. The support layer can be any suitable material, such as, for example, silicon or PMMA (polymethyl methacrylate). In step H, a protective capping layer may be applied. It should be understood that this is not strictly required, and a surface membrane without such a protective capping layer may be provided. Even so, the protective capping layer is beneficial for extending the operational life of the surface membrane. The capping layer may include any material used as the capping layer, such as, for example, yttrium oxide. In step I, the remaining silicon oxide may be etched away in HF etching, such that hydrofluoric acid selectively etches the silicon oxide, leaving the carbon nanotubes. Finally, step J depicts the final surface membrane comprising two bilayers of graphene separated by a carbon nanotube core.

[0142] Figure 9Additional details are provided regarding step F. In step I, a copper foil is provided, and a graphene layer is grown on the copper foil in step II. In step III, a PMMA and / or naphthalene layer is disposed on the side of the graphene layer opposite the copper foil. In step IV, the copper foil is etched away, leaving an exposed graphene layer with a PMMA support layer. The exposed graphene layer can then be applied to a planar CNT core layer so that the CNT core layer is sandwiched between opposing graphene layers. This invention provides a means for improving the stability of carbon nanotube membranes within EUV utilization equipment, such as photolithography equipment, and allows control over the degree of force required to allow CNTs to slide past each other. By increasing the resistance to relative movement (which can be considered as effective friction between CNTs), the resistance to the gaps between CNTs in the mesh forming the membrane can be increased. Alternatively or additionally, this disclosure provides a method for reducing the etching rate of hydrogen plasma by using metal nanowires to catalyze the recombination of hydrogen radicals and / or by preferentially reacting hydrogen radicals with hydrogen radical quenching or scavenging materials.

[0143] While specific embodiments of the invention have been described above, it should be understood that the invention may be practiced in other ways than those described.

[0144] The above description is intended to be illustrative and not restrictive. Therefore, those skilled in the art will understand that modifications can be made to the described invention without departing from the scope of the claims and aspects set forth below.

[0145] 1. A membrane for use as a membrane in an EUV utilization device, said membrane comprising randomly oriented uncoated carbon nanotubes having one, two, three, or each of the following:

[0146] i) an average diameter of less than 5 nm and a bundle (average) diameter of less than 30 nm, wherein the Young's modulus of the diaphragm is greater than 10 MPa;

[0147] ii) Surface features that provide roughness to the nanotubes so that the relative movement of the CNT tubes in the film is substantially blocked or suppressed;

[0148] iii) Hydrogen radical quenching agents or hydrogen radical scavenging materials; and

[0149] iv) Metal nanowire networks.

[0150] 2. The diaphragm according to aspect 1, wherein the Young's modulus is between about 10 MPa and about 200 MPa.

[0151] 3. The membrane according to aspect 1 or 2, wherein the areal density of carbon in the membrane is between 10 × 10⁻⁶. 15 C atoms / cm2 With 500×10 15 C atoms / cm 2 between.

[0152] 4. The membrane according to any one of aspects 1 to 3, wherein the carbon nanotubes have [8,3] chirality, [14,6] chirality or mixed chirality, optionally wherein the mixed chirality includes at least 30% [8,3] chiral CNTs.

[0153] 5. The diaphragm according to any one of aspects 1 to 4, wherein the CNT purity is at least 99 atomic% carbon and / or free of additives with a defect rate greater than 10 micrometers.

[0154] 6. The diaphragm according to any of the foregoing aspects, wherein the diaphragm has an EUV transmittance of greater than 90%.

[0155] 7. The diaphragm according to any of the foregoing aspects, wherein the diaphragm comprises single-walled nanotubes, double-walled nanotubes, multi-walled nanotubes, or a combination of any of the foregoing.

[0156] 8. The membrane according to any of the foregoing aspects, wherein the carbon nanotubes have a diameter of at most about 3 nm, at most about 2.5 nm, about 2 nm, about 1.5 nm or about 1 nm.

[0157] 9. The diaphragm according to any of the foregoing aspects, wherein the CNT surface features include defects, optionally wherein the defects include one or more of the following mechanisms: a) adsorbed atoms, b) chiral Stone-Wales effect, c) two missing C atoms, d) monovalent defects, and / or wherein the CNT surface features include functional groups.

[0158] 10. The diaphragm according to aspect 9, wherein the functional group comprises a hydrophobic group, a hydrophilic group, or a dipole-carrying group, or two or more of a hydrophobic group, a hydrophilic group, and a dipole-carrying group.

[0159] 11. The diaphragm according to aspect 10, wherein the hydrophobic group comprises one or more of phenyl, alkane, alkene and alkyne, and the dipole carrying group comprises hydroxyl.

[0160] 12. The diaphragm according to any of the foregoing aspects, wherein the CNT surface features include covalently bonded crosslinking groups that bond adjacent CNTs together.

[0161] 13. The membrane according to aspect 12, wherein the crosslinking group is one or more of the following: 1,4-benzoquinone, 1,5-hexadiene, aryl diazonium salt and poly(ethylene glycol) chain.

[0162] 14. The diaphragm according to aspect 12, wherein the crosslinking group is a product of free radical polymerization of CNTs or ion beam irradiation of CNTs, or a polymer coating.

[0163] 15. The diaphragm according to any of the foregoing aspects, wherein the CNT is a helical CNT.

[0164] 16. The diaphragm according to any of the foregoing aspects, wherein the surface feature is amorphous carbon.

[0165] 17. The diaphragm according to any of the foregoing aspects, wherein the metal nanowire network is a random network.

[0166] 18. The diaphragm according to any of the foregoing aspects, wherein the metal nanowires are unoxidized.

[0167] 19. The diaphragm according to any of the foregoing aspects, wherein the metal nanowires comprise at least one metal having high hydrogen recombination efficiency.

[0168] 20. The diaphragm according to any of the foregoing aspects, wherein the metal nanowires comprise rhodium, platinum, or a combination thereof.

[0169] 21. The membrane according to any of the foregoing aspects, wherein the diameter of the metal nanowire is less than, equal to or greater than the average diameter of the carbon nanotubes, and / or the bundle (average) diameter of the carbon nanotubes, and / or less than or equal to the thickness of the CNT membrane.

[0170] 22. The diaphragm according to any of the foregoing aspects, wherein the nanowires are electrospun nanowires.

[0171] 23. The diaphragm according to any of the foregoing aspects, wherein the nanowires are interwoven with the carbon nanotubes.

[0172] 24. The diaphragm according to any of the foregoing aspects, wherein the hydrogen scavenger or hydrogen quencher material is an alkyne, optionally wherein the hydrogen scavenger or hydrogen quencher material is disposed on the carbon nanotube.

[0173] 25. A separator for use as a surface film in an exposure apparatus for semiconductor manufacturing, the separator comprising a core comprising randomly oriented carbon nanotubes disposed between a first substantially planar top layer and a second substantially planar bottom layer.

[0174] 26. The diaphragm according to aspect 25, wherein the top layer and the bottom layer are the same or different.

[0175] 27. The diaphragm according to aspect 25 or aspect 26, wherein one or both of the top layer and the bottom layer comprise a 2D material, optionally wherein the material is selected from one or more of carbon-based, silicon-based and boron-based 2D materials, and / or graphene, silylene, TMDS (tetramethyldisiloxane), black phosphorus, carbon nitride, germanene, boronene, tinene, arsenene, aluminene, antimonene or bismuthene.

[0176] 28. The diaphragm according to any one of aspects 25 to 27, wherein one or both of the top layer and the bottom layer comprise molybdenum, ruthenium, beryllium or rhenium.

[0177] 29. The diaphragm according to any one of aspects 25 to 28, wherein the carbon nanotubes in the core are carbon nanotubes according to any one of aspects 1 to 24.

[0178] 30. The diaphragm according to any one of aspects 25 to 29, wherein the top layer and the bottom layer comprise additional conductive layers.

[0179] 31. The diaphragm according to any one of aspects 25 to 30, wherein one or both of the top layer and the bottom layer are continuous or at least partially formed of patches, optionally wherein the patches are separated by gaps of 4 micrometers or less.

[0180] 32. The diaphragm according to any one of aspects 25 to 31, wherein one or both of the top layer and the bottom layer are double-layered.

[0181] 33. The diaphragm according to any one of aspects 25 to 32, wherein one or both of the top layer and the bottom layer are provided with a capping layer, optionally wherein the capping layer comprises one or more of alumina, yttrium oxide and yttrium silicon oxide.

[0182] 34. The diaphragm according to any one of aspects 25 to 33, wherein the diaphragm has an emissivity greater than 50%, and / or wherein the conductivity of the top layer and / or the bottom layer is about 1 to about 6 MJ·kg. -1 ·m -1 .

[0183] 35. A membrane for an EUV utilization device, the membrane comprising a diaphragm according to any of the foregoing aspects and a support frame for supporting the diaphragm.

[0184] 36. An apparatus for extending the operational life of a membrane diaphragm, the apparatus being configured to provide a hydrogen radical quencher or hydrogen radical scavenger material to the membrane diaphragm.

[0185] 37. The apparatus according to aspect 36, wherein the apparatus includes a metering feeder of the hydrogen radical quencher or hydrogen radical scavenger material configured to guide the hydrogen radical quencher or hydrogen radical scavenger material toward the membrane diaphragm.

[0186] 38. The apparatus according to aspect 36 or 37, wherein the hydrogen radical quencher or hydrogen radical scavenger material comprises an alkyne, optionally wherein the alkyne is acetylene, propyne, or a combination thereof.

[0187] 39. The apparatus according to any one of aspects 36 to 38, wherein the apparatus includes a controller configured to control the supply of the hydrogen radical quencher or hydrogen radical scavenger material.

[0188] 40. The apparatus according to any one of aspects 36 to 39, wherein the apparatus is configured to provide the hydrogen radical quencher or hydrogen radical scavenger material to one or both of the front and back sides of the membrane.

[0189] 41. The apparatus according to any one of aspects 36 to 40, wherein the apparatus is configured to provide the hydrogen radical quencher or hydrogen radical scavenger material to the membrane at a rate sufficient to provide a single layer every 5 seconds or less, every 4 seconds or less, every 3 seconds or less, every 2 seconds or less, or every second or less.

[0190] 42. The apparatus according to any one of aspects 36 to 41, wherein the apparatus is configured to provide the hydrogen radical quencher or hydrogen radical scavenger material at a pressure of 0.10 mPa or less, 0.09 mPa or less, 0.08 mPa or less, 0.07 mPa or less, 0.06 mPa or less, 0.05 mPa or less, 0.04 mPa or less, 0.03 mPa or less, 0.02 mPa or less, or 0.01 mPa or less.

[0191] 43. An EUV utilization apparatus comprising a diaphragm, a membrane, or a device according to any of the foregoing aspects, wherein optionally the EUV utilization apparatus is an EUV lithography apparatus or an EUV inspection tool.

[0192] 44. A method of manufacturing a diaphragm for an EUV utilization device, the method comprising the steps of: i) providing surface features to a plurality of CNTs to prevent the CNTs from sliding over each other when formed into a CNT diaphragm, and ii) forming a CNT diaphragm of the CNTs.

[0193] 45. A method for extending the operational life of a carbon nanotube-based surface membrane, the method comprising one or both of the following:

[0194] i) Providing a hydrogen radical quencher or hydrogen radical scavenger material to the surface membrane diaphragm; and

[0195] ii) Provide a network of metal nanowires associated with the surface membrane diaphragm.

[0196] 46. ​​The method according to aspect 45, wherein the method includes providing an alkyne to the membrane as a hydrogen radical quencher or hydrogen radical scavenger material, optionally wherein the alkyne includes acetylene, propyne, or a combination thereof.

[0197] 47. The method according to aspect 45 or 46, wherein the method comprises providing the hydrogen radical quencher or hydrogen radical scavenger material to one or both of the front and back sides of the membrane.

[0198] 48. The method according to any one of aspects 45 to 47, wherein the hydrogen radical quencher or hydrogen radical scavenger material is provided in gaseous form.

[0199] 49. The method according to any one of aspects 45 to 48, wherein the supply of the hydrogen radical quencher or hydrogen radical scavenger material is controlled by the amount or concentration of hydrogen radicals generated in use.

[0200] 50. The method according to any one of aspects 45 to 49, wherein the method includes providing a network of metal nanowires interwoven with the carbon nanotubes.

[0201] 51. A method of manufacturing a diaphragm for an exposure apparatus for semiconductor manufacturing, the method comprising the steps of: i) providing a core film comprising a plurality of randomly oriented carbon nanotubes having a top surface and a bottom surface, and ii) providing substantially planar layers on the top surface and the bottom surface.

[0202] 52. The method according to aspect 51, wherein the method further comprises depositing silicon oxide on the core film prior to step ii).

[0203] 53. The method according to aspect 51 or aspect 52, wherein the method further comprises removing material from the top surface and / or the bottom surface prior to step ii) to provide a planar top surface and / or bottom surface.

[0204] 54. The method according to aspect 53, wherein the method further comprises providing a substantially planar layer on the top surface of the plane and a substantially planar layer on the bottom surface of the plane.

[0205] 55. The method according to aspect 54, wherein the method further includes removing any support layer from the diaphragm.

[0206] 56. The method according to any one of aspects 51 to 54, wherein the method further comprises providing a cover layer on one or both of the planar layer on the top surface and the planar layer on the bottom surface.

[0207] 57. The method according to any one of aspects 52 or 53 to 56, wherein, when subordinate to aspect 52, the method further comprises etching the silicon oxide deposited on the core film.

[0208] 58. Use of a diaphragm according to any one of aspects 1 to 34, a membrane according to aspect 35, an apparatus according to any one of aspects 36 to 42, an EUV utilization apparatus according to aspect 43, a method according to aspect 44, or a method according to any one of aspects 45 to 57, for use in a method or apparatus for using EUV.

[0209] 59. The use of an alkyne for extending the operational life of a carbon nanotube membrane diaphragm.

[0210] 60. An application of a metal nanowire for extending the operational life of a carbon nanotube membrane diaphragm.

Claims

1. A membrane for use as a membrane in an EUV utilization device, said membrane comprising randomly oriented uncoated carbon nanotubes having one, two, three, or each of the following: i) Average diameter less than 5 nm and beam (average) diameter less than 30 nm, where, The Young's modulus of the diaphragm is greater than 10 MPa; ii) Surface features that provide roughness to the nanotubes so that the relative movement of the CNT tubes in the film is substantially blocked or suppressed; iii) Hydrogen radical quenching agents or hydrogen radical scavenging materials; and iv) Metal nanowire networks.

2. The diaphragm according to claim 1, wherein, The Young's modulus is between about 10 MPa and about 200 MPa.

3. The diaphragm according to claim 1 or 2, wherein, The areal density of carbon in the membrane is between 10 × 10⁻⁶. 15 C atoms / cm 2 With 500×10 15 C atoms / cm 2 between.

4. The diaphragm according to any one of claims 1 to 3, wherein, The carbon nanotubes have [8,3] chirality, [14,6] chirality, or mixed chirality, optionally wherein the mixed chirality includes at least 30% [8,3] chiral CNTs.

5. The diaphragm according to any one of claims 1 to 4, wherein, CNTs must have a purity of at least 99 at% carbon and / or be free of additives with a defect rate greater than 10 micrometers.

6. The diaphragm according to any of the preceding claims, wherein, The diaphragm has an EUV transmittance of more than 90%.

7. The diaphragm according to any of the preceding claims, wherein, The diaphragm includes single-walled nanotubes, double-walled nanotubes, multi-walled nanotubes, or any combination thereof.

8. The diaphragm according to any of the preceding claims, wherein, The carbon nanotubes have a diameter of up to about 3 nm, up to about 2.5 nm, about 2 nm, about 1.5 nm, or about 1 nm.

9. The diaphragm according to any of the preceding claims, wherein, CNT surface features include defects, optionally including one or more of the following mechanisms: a) adsorbed atoms, b) chiral Stone-Wales effect, c) two missing C atoms, d) monovalent defects, and / or wherein the CNT surface features include functional groups.

10. The diaphragm according to claim 9, wherein, The functional group includes a hydrophobic group, a hydrophilic group, or a dipole-carrying group, or two or more of a hydrophobic group, a hydrophilic group, and a dipole-carrying group.

11. The diaphragm according to claim 10, wherein, The hydrophobic group includes one or more of phenyl, alkane, alkene and alkyne, and the dipole carrying group includes hydroxyl.

12. The diaphragm according to any of the preceding claims, wherein, The CNT surface features include covalently bonded crosslinking groups that bond adjacent CNTs together.

13. The diaphragm according to claim 12, wherein, The crosslinking group is one or more of the following: 1,4-benzoquinone, 1,5-hexadiene, aryl diazonium salt, and poly(ethylene glycol) chain.

14. The diaphragm according to claim 12, wherein, The crosslinking groups are the reaction products of free radical polymerization of CNTs or ion beam irradiation of CNTs, or polymer coatings.

15. The diaphragm according to any of the preceding claims, wherein, The CNTs mentioned are helical CNTs.

16. The diaphragm according to any of the preceding claims, wherein, The surface feature is amorphous carbon.

17. A membrane for an EUV utilization device, the membrane comprising a diaphragm according to any of the preceding claims and a support frame for supporting the diaphragm.

18. An apparatus for extending the operational life of a membrane diaphragm, the apparatus being configured to provide a hydrogen radical quencher or hydrogen radical scavenger material to the membrane diaphragm.

19. An EUV utilization apparatus comprising a diaphragm, a membrane, or a device according to any of the preceding claims, optionally wherein the EUV utilization apparatus is an EUV lithography apparatus or an EUV inspection tool.

20. A method for manufacturing a diaphragm for EUV utilization equipment, the method comprising the steps of: i) Providing surface features to the plurality of CNTs to prevent the CNTs from sliding on top of each other when formed into a CNT diaphragm, and ii) Forming a CNT diaphragm for these CNTs.

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