Flattened structure

Abstract

A method for producing a planarized structure containing a film of carbon nanostructures on a metal-containing or semimetallic coating layer, and the use of the planarized structure obtained by this method are disclosed. [Solution] This method includes the steps of: providing a prefilm of carbon nanostructures; forming a polymer-based material on the prefilm of carbon nanostructures to form a planarization layer on the prefilm of carbon nanostructures; forming a metal-containing or metalloid-containing material on the planarization layer to form a planarized metal-containing or metalloid-containing coating layer on the planarization layer; providing a film of carbon nanostructures on the planarized metal-containing or metalloid-containing coating layer to form a prestructure; subjecting the formed prestructure to a gas-phase densification treatment; and removing the planarization layer from the prefilm and prestructure of carbon nanostructures to produce a planarized structure.

Description

[[Technical Field]]

[0001] The present disclosure relates to a method for producing a planarized structure comprising a film of carbon nanostructures on a metal-containing or metalloid-containing coating layer. The present disclosure further relates to use of the resulting planarized structure. [[Background Art]]

[0002] Extreme ultraviolet lithography (EUV or EUVL) is an optical lithography technique that uses a specific range of extreme ultraviolet wavelengths. EUV pellicles are used to protect photomasks from defects, improve accuracy, shorten processing, and increase production efficiency on wafers. However, defects in printing remain a major constraint on the widespread adoption of EUV lithography. Furthermore, an optical filter is a component designed to selectively transmit or block light of a specific wavelength. These filters play a role in applications such as spectroscopy, communications, biomedical imaging, and photography. The materials and coating technologies used determine their performance, including spectral range, durability, and heat resistance. Despite their advantages, the performance of optical filters can be limited by challenges such as durability under high-power laser applications, thermal degradation, and manufacturing tolerances. Surface defects, coating mismatches, or environmental factors such as humidity can lead to scattering or absorption losses, reducing filter efficiency and service life. Therefore, there is a need for sophisticated filters such as EUV pellicles or optical filters. [[Summary of the Invention]]

[0003] Disclosed is a method of producing a planarized structure comprising a film of carbon nanostructures on a metal-containing or metalloid-containing coating layer. Said method comprises: providing a prefilm of carbon nanostructures, and forming a polymer-based material on the prefilm of carbon nanostructures by a first vapor deposition technique to form a planarization layer on the prefilm of carbon nanostructures, and The steps include forming a metal-containing or metalloid-containing material on the planarized layer by a second vapor-phase deposition technique, and forming a planarized metal-containing or metalloid-containing coating layer on the planarized layer, The steps include: providing a carbon nanostructure film on the planarized metal-containing or semimetallic coating layer to form a prestructure; The steps include subjecting the formed prestructure to a gas-phase densification treatment, The steps include: removing the planarization layer from the carbon nanostructure prefilm and the prestructure by dry etching to produce the planarized structure; Includes.

[0004] Furthermore, the use of planarization structures obtained by the methods disclosed herein as optical filters, debris filters, pellicles, membrane filters, electronic blocking windows, or any combination of at least two thereof is disclosed. [Brief explanation of the drawing]

[0005] The accompanying drawings are included to provide a further understanding of the embodiments, constitute part of this specification, illustrate the embodiments, and help illustrate the principles of the invention together with the description.

[0006] [Figure 1] One embodiment for manufacturing a flattened structure is shown. [Figure 2a] The results of Example 1 are shown. [Figure 2b] The results of Example 1 are shown. [Figure 3] The results of Example 2 are shown. [Modes for carrying out the invention]

[0007] This disclosure relates to a method for producing a planarized structure comprising a film of carbon nanostructures on a metal-containing or semimetallic coating layer, wherein the method is: • A step of providing a prefilm of carbon nanostructures, The first step is to form a polymer-based material on the prefilm of the carbon nanostructure by a first vapor-phase deposition technique to form a planarization layer on the prefilm of the carbon nanostructure, The steps include forming a metal-containing or metalloid-containing material on the planarized layer by a second vapor-phase deposition technique, and forming a planarized metal-containing or metalloid-containing coating layer on the planarized layer, The steps include: providing a carbon nanostructure film on the planarized metal-containing or semimetallic coating layer to form a prestructure; The steps include subjecting the formed prestructure to a gas-phase densification treatment, The steps include: removing the planarization layer from the carbon nanostructure prefilm and the prestructure by dry etching to produce the planarized structure; Includes.

[0008] This disclosure further relates to the use of planarization structures obtained by the methods disclosed herein as optical filters, debris filters, pellicles, membrane filters, electronic blocking windows, or any combination of at least two thereof.

[0009] In one embodiment, the planarized structure is used as an extreme ultraviolet lithographic pellicle.

[0010] In one embodiment, the planarized structure consists of a film of carbon nanostructures on a metal-containing or semimetallic coating layer.

[0011] In one embodiment, the carbon nanostructure prefilm is either a self-supporting carbon nanostructure prefilm or a mesh-supported carbon nanostructure prefilm.

[0012] In this specification, the term "mesh" may refer to an entangled structure. A mesh may be considered, for example, a support made of entangled strands of metal.

[0013] Carbon nanostructures are used to form a prefilm. The term "nanostructure" should be understood herein, unless otherwise specified, as a structure having one or more characteristic dimensions on a nanometer scale, typically in the range of 1 to 100 nm. The dimensions of a nanostructure may differ by a number of orders of magnitude in two perpendicular directions. For example, a nanostructure may have a length that is 10, 100, 1000, or even 100,000 times greater than its thickness or width.

[0014] In a (pre)film of carbon nanostructures, a large number of the carbon nanostructures are interconnected to form a network of interconnected molecules. Considered on a macroscale, such a network forms a solid monolithic material, where the individual molecular structures are either unoriented or unoriented, i.e., substantially randomly oriented or oriented. Various types of carbon nanostructure networks can be fabricated in the form of thin, transparent layers. In a film of carbon nanostructures collected from a forest, the carbon nanostructures retain an aligned or semi-aligned configuration in which the individual nanostructures are vertically oriented. When fabricated into a film, these structures may exhibit partial interconnection by van der Waals forces or physical entanglement, forming a network while retaining some of the alignment properties of the original forest.

[0015] In one embodiment, the carbon nanostructure is a carbon nanotube (CNT), a carbon nanobud (CNB), a carbon nanoribbon, a carbon nanofiber, or any combination or mixture thereof. In one embodiment, the carbon nanostructure is a carbon nanotube, a carbon nanobud, or any combination or mixture thereof. A carbon nanobud, or possibly a carbon nanobud molecule, has a fullerene or fullerene-like molecule covalently bonded to the side of a tubular carbon molecule. Carbon nanotubes and carbon nanobuds themselves have the additional utility of being highly transparent at X-ray and visible light wavelengths. Furthermore, they have strong mechanical properties and high chemical inertness.

[0016] In the art, various procedures exist that can be used for forming a (pre-)film of carbon nanostructures. Different approaches may be used to synthesize carbon nanostructures and / or to deposit them to form a film. For example, in the case of carbon nanotubes or carbon nanobud molecules, deposition may be carried out by using known methods such as, for example, filtration from a gas phase or a liquid, extraction from a solution, deposition in a force field, or deposition from a solution using spray coating or spin drying. Carbon nanobud molecules are synthesized, for example, using the method disclosed in WO 2007 / 057501, and can be deposited on a substrate directly from an aerosol flow, for example with the aid of electrophoresis or thermophoresis, or by the method described in Nasibulin et al., "Multifunctional Free-Standing Single-Walled Carbon Nanotube Films", ACS NANO, vol. 5, no. 4, 3214-3221, 2011. Functionalization of carbon nanostructures may be considered as the generation of functional groups on the surface of the carbon nanostructures. Functionalization of carbon nanostructures may be performed either by physisorption or covalent bonding. Functionalization of carbon nanostructures has additional utilities such as making them more reactive, increasing their solubility, or enabling various chemical modifications such as ion adsorption, metal deposition, or grafting reactions.

[0017] A (pre-)film of carbon nanostructures may be formed, for example, by synthesizing carbon nanostructures in a gas phase in which the carbon nanostructures are collected or deposited. Carbon nanostructures may be collected or deposited to form a film of carbon nanostructures having no specific orientation, or may be aligned in a specific direction.

[0018] The (pre-)film of carbon nanostructures has a size of 0.1 to 1000 cm 2 , or 1 to 500 cm 2 , or 5 to 350 cm 2 , or 10 to 200 cm2 or 50 to 150 cm 2 may have an area size of .

[0019] The thickness of the (pre)film of carbon nanostructures may be 1 to 8000 nm, or 5 to 7500 nm, or 15 to 7000 nm, or 20 to 5000 nm, or 50 to 2500 nm, or 100 to 1000 nm, or 200 to 600 nm. In one embodiment, the thickness of the (pre)film of carbon nanostructures is 1 to 600 nm, or 15 to 500 nm, or 20 to 400 nm, or 50 to 300 nm, or 100 to 200 nm, or 75 to 100 nm. In one embodiment, the thickness of the (pre)film of carbon nanostructures is 100 to 8000 nm, or 200 to 7000 nm, or 300 to 5000 nm, or 400 to 2500 nm, or 500 to 1000 nm. The thickness of the (pre)film of carbon nanostructures may be measured by a contact profilometer such as an atomic force microscope (AFM), an optical profilometer, ellipsometry, or a cross-sectional electron microscope. Forming a (pre)film of carbon nanostructures has the additional utility of enabling formation of a thin film. However, the (pre)film of carbon nanostructures must not be too thin, because if it is too thin, it will affect the ability of the film to support itself when forming a free-standing (pre)film.

[0020] Therefore, a prefilm of a carbon nanostructure may be a self-supporting prefilm of a carbon nanostructure. A self-supporting film may exist on its own without requiring a support substrate over its entire surface. A self-supporting prefilm of a carbon nanostructure may be self-supporting, meaning that the film has sufficient mechanical integrity and strength to independently maintain its structure. A self-supporting (pre)film may typically be formed directly as an independent entity, or a film grown on a substrate may be manufactured to be self-supporting after the substrate is removed. A defining characteristic of any self-supporting film may be its ability to maintain its structure without a support substrate. Whether or not a self-supporting film is formed on a substrate, it can be considered a self-supporting film if, after some processing step, it can exist and function independently, particularly as described above. Since a self-supporting film can maintain its structure without direct support, it does not need to be directly supported over its entire surface. This provides, by itself, an inherent structural support for maintaining its structure, for example, its shape. This can be observed under gravity in the absence of any supporting force for the self-supporting film. Therefore, the self-supporting (pre)film described herein may also be understood as a self-supporting (pre)film.

[0021] The (pre)film of the carbon nanostructure may be attached to a support as needed or desired. The support may be located anywhere on the structure to stabilize the (pre)film of the carbon nanostructure as needed, but the film itself can maintain its structure without requiring support over its entire area or over its freestanding areas.

[0022] The support may be any type of support suitable for bonding to a self-supporting (pre)film of the carbon nanostructure. The support may be formed from glass, metal, plastic, or any combination thereof. The form of the support may vary. The support may have the form of a frame. In one embodiment, the support has the form of a frame, and the (pre)film or carbon nanostructure is attached to the frame. The frame may support the self-supporting (pre)film of the carbon nanostructure at its outer edge so that an unsupported, independent region of the carbon nanostructure film is formed. The support positions may be located anywhere on the structure as long as they provide sufficient support to the carbon nanostructure film. For example, the support positions may be on the sides of the self-supporting (pre)film of the carbon nanostructure, in regions near the corners, or adjacent to each other along the sides. Broader regions including multiple support points are also intended to be covered by this embodiment, for example, when the frame has a continuous circular shape in which the self-supporting region is located within the circle. The frame may also have any other elongated, continuous shape. In one embodiment, the frame is molded to be circular, square, triangular, rectangular, elliptical, or polygonal.

[0023] A polymer-based material is formed on a prefilm of carbon nanostructures to create a planarization layer. As used herein, the term “polymer-based material” may be interpreted as referring to a material having a polymer content of 50–100% by weight. Examples of polymer-based materials used to form the planarization layer include organic polymers such as parylene and polyamides; naphthalene-containing polymers; oxygen-containing polymers such as poly(methyl methacrylate) (PMMA); hydrocarbon-based polymers consisting of carbon and hydrogen such as polystyrene; oligomers such as short-chain polystyrene and oligoethylene glycol; solvent-treated fluoropolymers such as polyvinylidene fluoride (PVDF); and polyolefins such as polypropylene, polyethylene, and polymethylpentene.

[0024] In one embodiment, the polymer-based material is an oxygen-free polymer-based material. Forming a planarization layer of a polymer-based material such as parylene has the additional benefit of not generating oxygen-containing byproducts during subsequent dry etching. Oxygen-containing byproducts can attack the formed metal-containing or metalloid-containing coating layer in a manner that adversely affects it.

[0025] In one embodiment, the polymer-based material is parylene.

[0026] The polymer-based material may be parylene. Parylene belongs to the poly-para-xylylene family. This family includes various types of parylene, such as parylene N, parylene C, parylene D, and parylene HT, which differ based on their chemical modifications. Parylene may be unsubstituted parylene (parylene N), chlorinated parylene (parylene C, parylene D), fluorinated parylene (parylene AF-4), alkyl-substituted parylene (parylene M, parylene E), reactive parylene (parylene A, parylene AM), colored parylene, or crosslinked parylene (parylene X). Colored parylene can be considered parylene having a chromophore that directly bonds to the [2.2]paracyclophane-based molecule to impart color to the parylene. Parylene N has the additional advantage of containing only carbon and hydrogen, and for this reason, its structure is close to that of a carbon nanotube or carbon nanobud. Therefore, parylene N has the additional advantage of not containing heteroatoms such as oxygen, nitrogen, or halogens that can interfere with carbon nanotube interactions.

[0027] Polymer-based materials can be formed on a prefilm of carbon nanostructures by a first vapor deposition technique. The vapor deposition technique may be any general-purpose method in which the material is deposited from the gas phase. In one embodiment, the first vapor deposition technique is thermal deposition, molecular layer deposition (MLD), or chemical vapor deposition (CVD). Using the first vapor deposition technique to form a planarization layer has the additional utility of allowing precise control of the thickness of the formed layer, enabling the formation of layer thicknesses up to tens of nanometers. Using the first vapor deposition technique also has the additional utility of efficiently filling any gaps present between carbon nanostructures in the prefilm without the need to form a thick layer. Forming a thin planarization layer has the additional utility of allowing subsequent dry etching techniques to be performed without adversely affecting the quality of the resulting metal-containing or metalloid-containing coating layer.

[0028] In one embodiment, the method includes the step of forming a planarization layer having a thickness of 1 to 200 nm, 5 to 180 nm, 10 to 150 nm, 20 to 100 nm, 30 to 80 nm, or 40 to 60 nm. The thickness of the planarization layer may be measured, for example, by using the cross-section of an electron microscope or X-ray reflectance.

[0029] Therefore, the planarization layer has the additional benefit of providing a smooth and uniform surface before forming a metal-containing or metalloid-containing coating layer on it. If there are irregularities on the surface at this stage, they will be transferred in a way that adversely affects the metal-containing or metalloid-containing coating layer, thus hindering the final use of the structure.

[0030] After the planar layer is formed, a metal-containing or metalloid-containing material is formed on it by a second vapor deposition technique to form a planar metal-containing or metalloid-containing coating layer. As used herein, the term “metal-containing material” may be interpreted as referring to a material containing a metal element or a metal-containing compound. In one embodiment, the metal-containing material has a metal content of 50 to 100% by weight. Thus, the planar metal-containing coating layer may contain a total of 50 to 100% by weight of metal or metal.

[0031] As used herein, the term “metalloid-containing material” may be interpreted as referring to a material containing a metalloid element or a metalloid-containing compound. In one embodiment, the metalloid-containing material has a metalloid content of 50 to 100% by weight. Therefore, the planarized metalloid-containing coating layer may contain a total of 50 to 100% by weight of metalloids.

[0032] In one embodiment, the second vapor deposition technique is selected from sputtering deposition, electron beam physical deposition, thermal deposition, cathode arc deposition, pulsed laser deposition, or ion beam assisted deposition. Sputtering deposition uses plasma to eject material from a target and then deposit it on a planar layer. Electron beam physical deposition utilizes a high-speed electron beam to evaporate the coating material and then condense it on a planar layer. Thermal deposition uses electrical resistance to heat the deposition material to a high vapor pressure, allowing it to be deposited on a planar layer. Cathode arc deposition uses a high-power electric arc to evaporate the target material and then deposit it on a planar layer. Pulsed laser deposition uses a high-power laser to ablate metal from a target, generating vapor which is then deposited on a planar layer. Ion beam assisted deposition combines physical vapor deposition with ion irradiation shock simultaneously to improve film properties.

[0033] Using a second vapor deposition technique to form a metal-containing or metalloid-containing coating layer has the additional benefit of being able to form a thin coating layer with a smooth and uniform surface.

[0034] In one embodiment, the metal-containing or metalloid-containing coating layer has a thickness of 1 to 300 nm, or 3 to 100 nm, or 5 to 50 nm, or 7 to 30 nm, or 9 to 20 nm, or 10 to 15 nm. The thickness of the metal-containing or metalloid-containing coating layer may be measured, for example, using transmission electron microscopy (TEM), scanning electron microscopy (SEM), or any other relevant technique.

[0035] In one embodiment, the metal-containing material is a material based on aluminum, zirconium, tungsten, molybdenum, titanium, yttrium, metal silicides, ruthenium, beryllium, gold, palladium, or niobium. The metal-containing coating layer may be formed from aluminum, zirconium, tungsten, molybdenum, titanium, yttrium, metal silicides, ruthenium, beryllium, gold, palladium, niobium, or any carbides, oxides, nitrides, sulfides, phosphides, oxynitrides, or borides thereof, or any combination or mixture thereof. The metal-containing coating layer may contain or consist of aluminum, zirconium, tungsten, molybdenum, titanium, yttrium, metal silicides, ruthenium, beryllium, gold, palladium, niobium, or any carbides, oxides, nitrides, sulfides, phosphides, oxynitrides, or borides thereof, or any combination or mixture thereof. In one embodiment, the metal-containing material is zirconium boride or molybdenum sulfide.

[0036] In one embodiment, the metalloid-containing material is a silicon or boron-based material. The metalloid-containing coating layer may be formed from boron or silicon, or any carbide, oxide, nitride, sulfide, phosphide, oxynitride, or boride thereof, or any combination or mixture thereof. The metalloid-containing coating layer may contain or consist of silicon or boron, or any carbide, oxide, nitride, sulfide, phosphide, oxynitride, or boride thereof, or any combination or mixture thereof.

[0037] In one embodiment, the metal-containing or semimetallic coating layer is a metal-containing or semimetallic shielding layer configured to block electromagnetic radiation having wavelengths greater than 400 nm, greater than 450 nm, or greater than 500 nm. The metal-containing or semimetallic coating layer has the additional utility of blocking radiation of undesirable wavelengths that would otherwise pass through the filter. The metal-containing or semimetallic coating layer has the further additional utility of functioning as a gas barrier.

[0038] In one embodiment, the planarized metal-containing or semimetallic coating layer comprises at least two layers made of different metallic materials that overlap each other, wherein one of the layers that faces the environment when the structure is used contains a metal that forms a metal oxide when in contact with air.

[0039] After forming the prestructure, it is subjected to a vapor densification treatment. In one embodiment, the vapor densification treatment is carried out using a vapor-phase solvent at a temperature of 55-75°C or 60-70°C for 1-120 seconds, 15-105 seconds, 20-90 seconds, or 30-60 seconds. The vapor-phase solvent may be isopropyl alcohol. The vapor densification treatment may be carried out using a vapor-phase solvent, i.e., a vaporized medium. The formed prestructure may be placed in a chamber into which solvent vapor is introduced. This solvent vapor can then condense on the prestructure, forming a thin liquid solvent film. The drying effect and surface tension of the solvent film can then cause the structures of the prestructure to attract each other, forming a denser and more mechanically robust structure. Densification of the prestructure has the additional utility of bonding or joining the carbon nanostructure film to a metal-containing or semimetallic coating layer so that they adhere to each other. The adhesion is maintained even under harsh conditions.

[0040] After vapor phase densification, the prefilm and planarization layer of the carbon nanostructure are removed from the prestructure by a dry etching technique to produce the planarized structure. In one embodiment, the dry etching technique is hydrogen plasma etching, inert gas plasma etching using, for example, argon or nitrogen plasma, laser ablation, or vacuum annealing. The dry etching technique has the additional advantage of being able to remove the planarization layer and the prefilm of the carbon nanostructure from the prestructure without attacking the metal-containing or metalloid-containing coating layer or the film of the carbon nanostructure. This may be due to the fact that in the dry etching technique, only the exposed surface is etched, and therefore, when the surface of the metal-containing or metalloid-containing coating layer is reached, the etching process stops. The dry etching technique has the additional advantage of being able to avoid oxidation that would adversely affect the remaining structure. For example, wet etching techniques typically use chemicals containing oxidizing agents, which can damage the carbon nanostructure, potentially resulting in, for example, impaired electrical properties of the carbon nanostructure or the introduction of unwanted oxygen functional groups on the surface of the carbon nanostructure.

[0041] In this way, a planarized structure exhibiting a smooth and uniform surface is formed, as described above. The roughness of the EUV pellicle, such as the average surface roughness value measured as Ra, must be at most 50 nm in order to meet the performance standards of EUV lithography. Surface roughness is crucial for minimizing the scattering of EUV light and maintaining optical and mechanical performance under high thermal and radiative loads.

[0042] The planarized structures obtained by the methods disclosed herein may exhibit an average surface roughness value Ra of 50 nm or less on at least one side, as determined by atomic force microscopy.

[0043] As used herein, the term “average surface roughness” may be interpreted as referring to the microscopic roughness of a surface, such as a planarized metal-containing or semimetallic coating layer, measured in nanometer units using an atomic force microscope. This measurement differs from the macroscopic flatness of a flexible planarized structure in relation to the overall shape and flatness of the planarized structure on a larger scale. The average surface roughness value Ra is 10 × 10 μm 2 It can also be the average value calculated between peaks and valleys in the surface area. A lower Ra value indicates less variation between peaks and valleys on the surface, resulting in a smoother surface.

[0044] The planarized structures obtained by the methods disclosed herein have the additional utility of possessing properties such as average surface roughness and transmittance percentage values, which enable use and proper function under extreme ultraviolet light and high vacuum conditions.

[0045] In one embodiment, a planarized structure is fabricated on at least one side exhibiting an average surface roughness value Ra of up to 50 nm, or up to 45 nm, or up to 40 nm, or up to 35 nm, or up to 30 nm. In one embodiment, a planarized structure is fabricated on at least one side exhibiting an average surface roughness value Rs of 0.1 to 0.5 nm. In one embodiment, a planarized structure is fabricated on at least one side exhibiting an average surface roughness value Rs of 0.1 to 10 nm, or 0.5 to 7 nm, or 1 to 4 nm. The Ra and Rs values ​​may be determined using a profilometer such as atomic force microscopy (AFM).

[0046] The planarized structure formed may be considered to have two sides, one formed of a planarized metal-containing or semimetallic coating layer and the other formed of a carbon nanostructure film. At least one of these sides may exhibit an average surface roughness value Ra of up to 50 nm, up to 45 nm, or up to 40 nm, or up to 35 nm, or up to 30 nm. In one embodiment, both sides of the planarized structure exhibit an average surface roughness value Ra of up to 50 nm, up to 45 nm, or up to 40 nm, or up to 35 nm, or up to 30 nm. In one embodiment, the planarized structure exhibits an average surface roughness value Ra of up to 50 nm, up to 45 nm, or up to 40 nm, or up to 35 nm, or up to 30 nm on the sides of the planarized metal-containing or semimetallic coating layer. In one embodiment, a planarized structure is manufactured having an average surface roughness value Ra of 0.1 to 10 nm, or 0.5 to 7 nm, or 1 to 4 nm on each of its faces.

[0047] In one embodiment, a planarized structure is fabricated on at least one side thereof, exhibiting an average surface roughness value Ra of up to 1 nm and an Rs of up to 10 nm or up to 5 nm. Such values ​​may be used.

[0048] In one embodiment, a planarized structure is manufactured on at least one side exhibiting an average surface roughness value Ra of up to 5 nm or up to 2 nm, and an Rs of up to 20 nm or up to 10 nm.

[0049] In one embodiment, a planarized structure is manufactured on at least one side exhibiting an average surface roughness value Ra of up to 0.2 nm or up to 0.1 nm, and an Rs of up to 1 nm or up to 0.5 nm. In one embodiment, the planarized structure obtained by the method disclosed herein exhibits a transmittance percentage value (%T) of 0-30%, 1-20%, 2-10%, or 4-8% when measured in the wavelength range of 380-780 nm.

[0050] In one embodiment, the planarized structure obtained by the method disclosed herein is an optical filter that exhibits a transmittance percentage value (%T) of 0-30%, 1-20%, 2-10%, or 4-8% when measured in the wavelength range of 380-780 nm.

[0051] In one embodiment, the planarized structure obtained by the method disclosed herein exhibits a transmittance percentage value (%T) of 45-95%, 50-90%, or 55-85% when measured in the wavelength range of 13.3-13.7 nm. In one embodiment, the planarized structure obtained by the method disclosed herein is an EUV pellicle and exhibits a transmittance percentage value (%T) of 45-95%, 50-90%, or 55-85% when measured in the wavelength range of 13.3-13.7 nm.

[0052] The percentage transmittance value may be measured by spectroscopy. The term "percent transmittance value" may be used instead of "percentage transmittance value."

[0053] The planarized structures formed by the methods disclosed herein have the additional benefit of exhibiting a smooth and uniform surface, which is required in many applications. The carbon nanostructure layer may be a porous film with pinholes, which can result in a coarse or rough surface. The methods disclosed herein have the additional benefit of forming a smooth, pinhole-free surface by planarizing the surface of a prefilm of carbon nanostructures, which also contributes to the smoothness of subsequently laminated metal-containing or semimetallic coating layers. The smooth surface of the planarized structure has the additional benefit of improving the visible transmittance of the structure.

[0054] In one embodiment, the method for manufacturing a planarized structure is a dry method for manufacturing a planarized structure. The term “dry method” may refer to the fact that throughout the entire manufacturing process, only gas-phase techniques are used to manufacture the layers / films, and no liquid or solvent-based techniques are used. In one embodiment, no liquid-based or solvent-based techniques are used in this method. A so-called “dry method” has the additional utility of providing such a smooth surface to the formed structure. The gas-phase techniques used in this method have the additional utility of not only allowing for precise thickness control of different layers, but also enabling the formation of truly smooth and uniform surfaces for each layer.

[0055] Solvent-based processes typically involve wetting and drying steps, which often lead to cracking and structural collapse in the formed layer due to surface tension and capillary action. Such collapses may be avoided by methods as described herein.

[0056] The formed planarized structure may be used for different applications. In one embodiment, the planarized structure is an optical filter, a debris filter, a pellicle, a membrane filter, an electronic stop window, or any combination of at least two of these.

[0057] Furthermore, using a planarization layer on a carbon nanostructure prefilm to form a metal-containing or metalloid-containing coating layer on top of it has the additional benefit of reducing or suppressing oxidation reactions. [Examples]

[0058] The embodiments described here will be explained in detail, but examples are shown in the attached drawings.

[0059] The following description discloses several embodiments in such detail that a person skilled in the art could utilize the method based on this disclosure. Not all steps of the embodiments are discussed in detail, as some steps may be obvious to a person skilled in the art based on this specification.

[0060] Figure 1 shows one embodiment for manufacturing the planarized structure disclosed herein.

[0061] First, a prefilm of carbon nanostructures is provided. The prefilm of carbon nanostructures may be formed, for example, by a gas-phase process, where carbon nanostructures such as carbon nanotubes (indicated as CNTs in Figure 1) are synthesized in the gas phase and then deposited or collected on a substrate such as a porous filter. The formed prefilm of carbon nanostructures can be peeled from the substrate and transferred to a support such as a frame.

[0062] Next, a polymer-based material (indicated as parylene in Figure 1) is formed on a prefilm of carbon nanostructures by a first vapor-phase deposition technique, and a planarization layer is formed on the aforementioned prefilm of carbon nanostructures.

[0063] Next, a metal-containing material (labeled as "metal" in Figure 1) is formed on the planarization layer (parylene) using a second vapor deposition technique, and a planarized metal-containing coating layer is formed on the planarization layer.

[0064] Next, a film of carbon nanostructures (denoted as CNTs) is provided on a planar metal coating layer (metal) to form a prestructure.

[0065] Following these steps, the formed prestructure is subjected to vapor densification, and then the carbon nanostructure prefilm and planarization layer are removed from the prestructure by dry etching to produce the planarized structure. Thus, the planarized structure is formed from a planarized metal-containing coating layer and a film of carbon nanostructures (CNTs).

[0066] (Example 1 - Manufacturing of a flattened structure) In this example, different planarized structures were fabricated and tested. The materials used are shown in Table 1. [Table 1]

[0067] First, carbon nanotubes were synthesized in an aerosol laminar flow (floating catalyst) reactor using carbon monoxide as the carbon source and ferrocene as the catalyst precursor. The formed carbon nanotubes were deposited from the gas phase onto a porous collection filter at a total gas flow rate of 60 l / min (maximum gas velocity of 0.13 m / s) to form a carbon nanotube prefilm on the porous collection filter. The gas temperature was approximately 60°C. The thickness of the first carbon nanotube prefilm was 50 nm, which corresponds to 81%T at a wavelength of 550 nm.

[0068] Next, the formed carbon nanotube prefilm was transferred from the porous collection filter to a rectangular plastic frame larger than the final circular frame. This was then transferred to the final circular frame to form a self-supporting carbon nanotube prefilm attached to the frame. Thus, the frame had a circular shape with an opening in the center.

[0069] Subsequently, a polymer-based material was deposited on a carbon nanotube prefilm. In this example, parylene N was used as the polymer-based material. The planarization layer was formed using thermal deposition as follows: di-p-xylene (dimer) was thermally decomposed at approximately 680°C under vacuum conditions, and then deposited on a low-temperature (i.e., room temperature) substrate in a deposition chamber under continuous vacuum. The thickness of the parylene planarization layer was 130 nm.

[0070] Next, a second vapor deposition technique, in this case spats-turring deposition using Ar plasma, was used to form a metal-containing Mo coating layer on the planarized layer (base pressure 1E-5 mbar, operating pressure 1E-3 mbar, deposition rate approximately 5 Å / sec, unheated sample, spats-turring target pre-washed for 1 minute, then degreased to remove natural oxides). The thickness of this metal-containing coating layer was 40 nm.

[0071] Next, a film of carbon nanotubes manufactured as described above was formed on the metal-containing coating layer.

[0072] Next, the formed prestructure was placed in a chamber, and isopropanol vapor was introduced into it at a temperature of 66°C for 60 seconds to perform a vapor-phase densification treatment on the prestructure.

[0073] After vapor-phase densification, the carbon nanotube prefilm and planarization layer were removed from the prestructure using hydrogen plasma etching (RF output 40W, hydrogen 20 sccm, base pressure 1 mbar, operating pressure 500 mbar, 40 minutes).

[0074] The formed planarized structures were subjected to EUV and DUV (deep ultraviolet) measurements using a particle accelerator (synchrotron). The pre-structures were also subjected to the same measurements as the reference samples. The results are shown in Figures 2a and 2b.

[0075] (Example 2 - Testing of flattened structure) In this example, pre-films of carbon nanotubes and pre-structures fabricated as in Example 1 were subjected to different procedures to remove the parylene planarization layer therefrom. Hydrogen plasma etching (RF power 40 W, hydrogen 20 sccm, base pressure 1 mbar, operating pressure 500 mbar, 40 minutes) was used and compared with solvents (cyclohexane, dioxane, and dimethylformamide). The comparison samples were held in these solvents at room temperature for 30 minutes. The test results are shown in Figure 3. From these results, it can be seen that the tested solvents did not remove the parylene planarization layer.

[0076] (Example 3 - Testing of flattened structure) In this example, a planarized structure manufactured according to the description in Example 2 was tested and compared with a sample in which a metal-containing coating layer was directly formed on a carbon nanotube film without using a planarized layer. A Mo-containing coating layer was formed as the metal-containing coating layer for both the example sample and the comparative sample.

[0077] The formed samples were subjected to EUV and DUV (deep ultraviolet) measurements using a particle accelerator (synchrotron).

[0078] These results show that when a planarized structure was fabricated, that is, when a planarized layer of polymer-based material was used and a Mo-containing coating layer was formed on top of it, the visible transmittance was approximately 2%, whereas when the same material was formed directly on a carbon nanostructure film without using a planarized layer of polymer-based material, the visible transmittance was approximately 10%.

[0079] This difference in visible transmittance can be concluded to be due to pinholes in the porous carbon nanotube film, in contrast to the case where a Mo-containing coating layer is formed on the planarization layer, the surface is continuous, and ideally there are no pinholes.

[0080] Furthermore, it was concluded that directly forming a molybdenum-containing coating layer on a porous carbon nanotube film leads to oxidation due to its disordered morphology, which in turn increases chemical reactivity.

[0081] As technology advances, it is obvious to those skilled in the art that basic ideas can be implemented in a variety of ways. Therefore, the embodiments are not limited to the examples described above and may be modified within the scope of the claims.

[0082] The embodiments described above may be used in any combination. Some of the embodiments may be combined together to form further embodiments. Methods or uses disclosed herein may include at least one of the embodiments described herein. It will be understood that the benefits and advantages described above may relate to one embodiment or to several embodiments. Embodiments are not limited to solving any or all of the problems described or having any or all of the benefits and advantages described. It will also be understood that a reference to "one" item may refer to one or more of these items. The term "comprising" is used herein to mean including the following features or actions and not to exclude the presence of one or more additional features or actions.

Claims

1. A method for producing a planarized structure containing a film of carbon nanostructures on a metal-containing or semimetallic coating layer, - A step of providing a prefilm of carbon nanostructures, - A step of forming a polymer-based material on the prefilm of the carbon nanostructure by a first vapor-phase deposition technique to form a planarization layer on the prefilm of the carbon nanostructure, - A step of forming a metal-containing or metalloid-containing material on the planarized layer by a second vapor-phase deposition technique, and forming a planarized metal-containing or metalloid-containing coating layer on the planarized layer, - A step of providing a film of carbon nanostructures on the planarized metal-containing or semimetallic coating layer to form a prestructure, - A step of subjecting the formed prestructure to a gas-phase densification treatment, - A step of manufacturing the planar structure by removing the planarization layer from the carbon nanostructure prefilm and the prestructure using a dry etching technique, Methods that include...

2. The method according to claim 1, wherein the prefilm of the carbon nanostructure is a self-supporting prefilm of the carbon nanostructure or a mesh-supported prefilm of the carbon nanostructure.

3. The method according to claim 1 or 2, wherein the polymer-based material is an oxygen-free polymer material.

4. The method according to claim 1 or 2, wherein the first vapor deposition technique is thermal deposition, molecular layer deposition (MLD), or chemical vapor deposition (CVD).

5. The method according to claim 1 or 2, comprising the step of forming a planarized layer having a thickness of 1 to 200 nm, or 5 to 180 nm, or 10 to 150 nm, or 20 to 100 nm, or 30 to 80 nm, or 40 to 60 nm.

6. The method according to claim 1 or 2, wherein the second vapor deposition technique is selected from sputtering deposition, electron beam physical deposition, thermal deposition, cathode arc deposition, pulsed laser deposition, or ion beam assisted deposition.

7. The method according to claim 1 or 2, wherein the metal-containing material is a material based on aluminum, zirconium, tungsten, molybdenum, titanium, yttrium, metal silicide, ruthenium, beryllium, gold, palladium, or niobium.

8. The method according to claim 1 or 2, wherein the semimetallic material is a silicon or boron-based material.

9. The method according to claim 1 or 2, wherein the dry etching technique is hydrogen plasma etching, inert gas plasma etching, laser ablation, or vacuum annealing.

10. The method according to claim 1 or 2, wherein the planarized metal-containing or metalloid-containing coating layer comprises at least two layers made of different metallic materials that overlap each other, and one of the layers that faces the environment when the planarized structure is used contains a metal that forms a metal oxide when in contact with air.

11. The method according to claim 1 or 2, wherein the gas phase densification treatment is carried out using a gas phase solvent at a temperature of 55 to 75°C or 60 to 70°C for 15 to 120 seconds, or 20 to 90 seconds, or 30 to 60 seconds.

12. The method according to claim 1 or 2, wherein the planarized structure exhibits a transmittance percentage value (%T) of 0-30%, 1-20%, 2-10%, or 4-8% when measured in the wavelength range of 380-780 nm.

13. The method according to claim 1 or 2, wherein the planarized structure exhibits a transmittance percentage value (%T) of 45-95%, 50-90%, or 55-85% when measured in the wavelength range of 13.3-13.7 nm.

14. The method according to claim 1 or 2, wherein the planarization structure is an optical filter, a debris filter, a pellicle, a membrane filter, an electronic blocking window, or any combination of at least two thereof.

15. Use of a planarization structure obtained by the method of claim 1 or 2, as an optical filter, a debris filter, a pellicle, a membrane filter, an electronic blocking window, or any combination of at least two thereof.

16. The use according to claim 15, wherein the planarized structure is used as an extreme ultraviolet lithographic pellicle.

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