Protective film and its components and component frames, component manufacturing methods, exposure originals, exposure apparatus, and semiconductor device manufacturing methods.

Abstract

This invention provides a protective film with further high EUV transmittance, its components and a component frame, and a method for manufacturing the component. Furthermore, it provides a method for manufacturing an exposure master, an exposure apparatus, and a semiconductor device capable of high-precision EUV lithography. The protective film of this invention is an exposure protective film laid on the opening of a support frame. The thickness of the protective film is less than 200 nm. The protective film includes carbon nanotube sheets, each carbon nanotube sheet comprising bundles formed of multiple carbon nanotubes. The diameter of each bundle is less than 100 nm. The bundles are oriented in-plane within the carbon nanotube sheets. The ratio R of the peak intensity in the thickness direction of the carbon nanotube sheets to the peak intensity in the in-plane direction of the carbon nanotube sheets is... B It is above 0.40.

Description

[0001] This application is a divisional application of the invention patent application with application number 201780038819.9, application date July 3, 2017, entitled "Protective film, protective film assembly frame, protective film assembly, manufacturing method thereof, exposure original, exposure device, and manufacturing method of semiconductor device". Technical Field

[0002] This invention relates to photomasks or intermediate masks (hereinafter collectively referred to as "photomasks") used in manufacturing semiconductor devices using photolithography, and protective film assemblies serving as dust covers for photomasks to prevent dust adhesion. In particular, this invention relates to protective films for extreme thin films used in extreme ultraviolet (EUV) lithography, protective film assembly frames, protective film assemblies, methods for manufacturing the same, and methods for manufacturing exposure templates and semiconductor devices using these materials. Background Technology

[0003] Semiconductor devices are manufactured through a process called photolithography. In photolithography, a scanner, or an exposure device called a stepper, is used to expose a mask with a circuit pattern to light, transferring the circuit pattern onto a semiconductor wafer coated with photoresist. If foreign matter such as dust adheres to the mask, its shadow will be transferred to the semiconductor wafer, preventing accurate transfer of the circuit pattern. As a result, sometimes the semiconductor device will malfunction and become a defective product.

[0004] In contrast, it is known to mount a protective film assembly, including a support frame with a protective film adhered to it, onto a mask, thereby preventing foreign matter such as dust from adhering to the protective film and thus preventing it from adhering to the mask. The focus of the exposure light of the exposure apparatus is set on the mask surface and the semiconductor wafer surface, and not on the protective film surface. Therefore, the shadow of foreign matter adhering to the protective film will not be imaged on the semiconductor wafer. Thus, when foreign matter adheres to the protective film, the degree to which it hinders the transfer of circuit patterns is significantly reduced compared to when foreign matter adheres to the mask, significantly suppressing the defect rate of semiconductor components.

[0005] The protective films used in protective film assemblies are required to have the characteristic of allowing exposure light to pass through with high transmittance. This is because if the transmittance of the protective film is low, the intensity of exposure light from the mask on which the circuit pattern is formed will be reduced, and the photoresist formed on the semiconductor wafer will not be sufficiently photosensitive.

[0006] To date, the wavelength of photolithography has been continuously shortening, and EUV lithography is being developed as the next generation of photolithography technology. EUV light refers to light with wavelengths in the soft X-ray region or vacuum ultraviolet region, specifically light with a wavelength of approximately 13.5 nm ± 0.3 nm. In photolithography, the resolution limit of a pattern is approximately half the exposure wavelength, and it is said that even using immersion lithography, the limit is only about one-quarter of the exposure wavelength. It is predicted that even using ArF laser (wavelength: 193 nm) in immersion lithography, the exposure wavelength limit is around 45 nm. Therefore, EUV lithography is highly anticipated as a revolutionary technology that can achieve significant miniaturization compared to previous photolithography methods.

[0007] Here, EUV light is readily absorbed by all materials. Furthermore, if exposure light such as EUV light is irradiated onto the protective film, a portion of its energy is absorbed by the protective film. Moreover, the energy of the EUV light absorbed by the protective film is converted into heat through various relaxation processes. Therefore, the temperature of the protective film rises during exposure. In addition, protective film assemblies for EUV applications require extremely thin films, such as nanometer-scale films, to be attached to the protective film assembly. Therefore, considering factors such as heat dissipation and heat resistance during temperature rise, a protective film with even higher EUV transmittance is needed.

[0008] Patent document 1 discloses an invention relating to "optical elements for photolithography apparatus", which in particular describes the following: the use of carbon nanotube sheets; which may comprise "single-layer carbon nanotube sheets" or "multi-layer carbon nanotube sheets"; the advantage of nanotube sheets is their lower density.

[0009] Patent document 2 relates to protective films and protective film components, and states that: if the density is increased in order to obtain film strength, high transmittance cannot be obtained; carbon nanotubes contain many impurities such as metals during the manufacturing process, resulting in poor transmittance.

[0010] Patent document 3 discloses carbon nanotube sheets with diameters of 3nm to 8nm and 10nm to 15nm.

[0011] Patent document 4 discloses carbon nanotube sheets with a cylindrical diameter of about 1 nm to 1000 nm, an axial length of about 0.1 μm to 1000 μm, and an L / D ratio of about 100 to 10000.

[0012] Existing technical documents

[0013] Patent documents

[0014] Patent Document 1: Japanese Patent Publication No. 2011-530184

[0015] Patent Document 2: International Publication No. 2014 / 142125

[0016] Patent Document 3: Japanese Patent Application Publication No. 2001-48507

[0017] Patent Document 4: Japanese Patent Application Publication No. 2006-69165 Summary of the Invention

[0018] The problem that the invention aims to solve

[0019] This invention provides a protective film with further improved EUV transmittance and superior heat resistance compared to the aforementioned existing literature, as well as a protective film assembly frame and a protective film assembly. Furthermore, it provides a method for manufacturing an exposure master and a semiconductor device capable of high-precision EUV lithography.

[0020] Methods for solving problems

[0021] To address the aforementioned issues, an exposure protective film is provided, which is laid on the opening of a support frame. The thickness of the protective film is less than 200 nm. The protective film includes a carbon nanotube sheet, which has a bundle formed of multiple carbon nanotubes with a diameter of less than 100 nm. The bundle is oriented in-plane within the carbon nanotube sheet.

[0022] With the above configuration, a protective film can be provided that simultaneously satisfies the following conditions: the thickness of the protective film is less than 200 nm, the protective film includes carbon nanotube sheets, the carbon nanotube sheets have bundles formed of multiple carbon nanotubes, the diameter of the bundles is less than 100 nm, and the bundles are in-plane oriented within the carbon nanotube sheets; such a protective film has high EUV transmittance, excellent EUV durability, and film strength that can withstand the manufacturing process of the protective film assembly and the atmospheric pressure to vacuum process in the EUV exposure system.

[0023] In one embodiment of the present invention, the diameter of the carbon nanotube can be above 0.8 nm and below 6 nm.

[0024] In one embodiment of the invention, the carbon nanotube sheet may have a mesh structure formed by bundling in the planar direction.

[0025] In one embodiment of the invention, a protective layer may be further included in contact with the carbon nanotube sheet.

[0026] In one embodiment of the invention, the protective layer may comprise SiO2. x (x≤2), Si a N b (a / b is 0.7 to 1.5), and one or more of the following groups: SiON, Y2O3, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, B4C, SiC and Rh.

[0027] In addition, to solve the above-mentioned problems, a protective film is provided, which includes a carbon nanotube sheet, wherein the diameter of the carbon nanotube is 0.8 nm to 6 nm, the length of the carbon nanotube is 10 μm to 10 cm, and the carbon content in the carbon nanotube is 98% by mass or more.

[0028] With the above configuration, a protective film can be provided that simultaneously meets three conditions: the carbon content in the carbon nanotubes is 98% or more by mass, the diameter of the carbon nanotubes is 0.8 nm or more and 6 nm or less, and the length of the carbon nanotubes is 10 μm or more and 10 cm or less. Such a protective film has high EUV transmittance, excellent EUV durability, and film strength that can withstand the atmospheric pressure to vacuum process in the protective film assembly manufacturing process and the EUV exposure system.

[0029] In one embodiment of the invention, the length-to-diameter ratio (length / diameter) of the carbon nanotube can be 1×10⁻⁶. 4 Above 1×10 8 the following.

[0030] If the diameter of the carbon nanotubes is small, although the strength of the protective film increases, the EUV transmittance decreases. Therefore, to simultaneously satisfy EUV transmittance and film strength, the ratio of the nanotube diameter to its length (length / diameter) is important. A ratio of 1 × 10⁻⁶ is preferable. 4 Above 1×10 8 The following can simultaneously satisfy EUV transmittance and film strength.

[0031] In one embodiment of the invention, the protective film may further include a protective layer in contact with the carbon nanotube sheet. The protective layer may be disposed on the original side of the protective film, or it may be disposed on the outermost surface of the protective film.

[0032] In one embodiment of the invention, the protective layer may comprise SiO2. x (x≤2), Si a N b (a / b is 0.7 to 1.5), and one or more of the following groups: SiON, Y2O3, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, B4C, SiC and Rh.

[0033] By setting a protective layer, the protective film can be endowed with both hydrogen radical resistance (i.e., reduction resistance) and oxidation resistance.

[0034] In one embodiment of the present invention, a protective film assembly may be provided, comprising: the protective film described above, and a support frame for supporting the protective film.

[0035] In one embodiment of the present invention, a protective film assembly frame may be provided, comprising: the aforementioned protective film, and a first frame supporting the protective film.

[0036] In one embodiment of the present invention, a protective film assembly may be provided, comprising: the aforementioned protective film assembly frame, and a second frame connected to the protective film assembly frame.

[0037] In one embodiment of the present invention, an exposure template may be provided, comprising: the template and a protective film assembly mounted on the patterned side of the template.

[0038] In one embodiment of the present invention, an exposure apparatus may be provided having the above-described exposure original.

[0039] In one embodiment of the present invention, an exposure apparatus may be provided, comprising: a light source emitting exposure light, the aforementioned exposure plate, and an optical system for guiding the exposure light emitted from the light source to the exposure plate, wherein the exposure plate is configured such that the exposure light emitted from the light source passes through the aforementioned protective film and irradiates the plate.

[0040] In one embodiment of the present invention, the exposure light can be EUV light.

[0041] In one embodiment of the present invention, a method for manufacturing a semiconductor device is provided, comprising the steps of: irradiating a master plate with exposure light emitted from a light source through a protective film of the master plate, and reflecting the light onto the master plate; and irradiating a sensing substrate with exposure light reflected from the master plate through the protective film, thereby exposing the sensing substrate into a pattern.

[0042] In one embodiment of the present invention, the exposure light can be EUV light.

[0043] In one embodiment of the present invention, a method for manufacturing a protective film assembly is provided, comprising: using chemical vapor deposition (CVD) to add water vapor at a temperature of 10 ppm to 10,000 ppm in the presence of a metal catalyst to produce carbon nanotubes; forming the obtained carbon nanotubes into a sheet to produce a carbon nanotube sheet; and connecting the obtained carbon nanotube sheet to a support frame having an opening in a manner that covers the opening surface.

[0044] A method for manufacturing a protective film assembly is provided, comprising: manufacturing a carbon nanotube sheet from a dispersion of carbon nanotubes, and connecting the resulting carbon nanotube sheet to a support frame having an opening in such a way as to cover the opening surface.

[0045] In one embodiment of the present invention, a method for manufacturing a protective film assembly is provided, wherein a metal catalyst is disposed on a substrate for chemical vapor deposition.

[0046] In one embodiment of the present invention, a method for manufacturing a protective film assembly is provided, comprising: patterning a metal catalyst on a substrate for chemical vapor deposition; adding water vapor at a temperature of 10 ppm to 10,000 ppm in the presence of the metal catalyst at a temperature of 600°C to 1000°C; forming multiple monolayer carbon nanotubes by CVD to manufacture an integral carbon nanotube structure; forming the obtained integral carbon nanotube structure into a sheet to manufacture a carbon nanotube sheet; and connecting the obtained carbon nanotube sheet to a support frame having an opening in a manner that covers the opening surface. Forming multiple monolayer carbon nanotubes by CVD can also be achieved by forming multiple monolayer carbon nanotubes erected in a direction perpendicular to the substrate surface by CVD.

[0047] In one embodiment of the present invention, a method for manufacturing a protective film assembly is provided, comprising: manufacturing a carbon nanotube sheet from a dispersion of carbon nanotubes, and connecting the resulting carbon nanotube sheet to a support frame having an opening in such a way as to cover the opening surface.

[0048] The effects of the invention

[0049] It can provide protective films with high EUV transmittance and excellent heat resistance, protective film assembly frames, and protective film assemblies. Furthermore, by using exposure masters based on these protective films, protective film assembly frames, and protective film assemblies, it is possible to provide exposure masters and semiconductor device manufacturing methods that can form miniaturized patterns (e.g., linewidths below 32 nm) through EUV light and reduce image degradation caused by foreign matter during pattern exposure. Attached Figure Description

[0050] Figure 1 This is a schematic diagram (cross-sectional view) illustrating the manufacturing process of a protective film, a protective film assembly frame, and a protective film assembly according to one embodiment of the present invention.

[0051] Figure 2 This is a schematic diagram (cross-sectional view) illustrating the manufacturing process of a protective film, a protective film assembly frame, and a protective film assembly according to one embodiment of the present invention.

[0052] Figure 3 This is a flowchart illustrating a method for manufacturing a protective film, a protective film assembly frame, and a protective film assembly according to one embodiment of the present invention.

[0053] Figure 4 This is a selected area electron beam diffraction image of a cross-section of a carbon nanotube sheet according to one embodiment of the present invention.

[0054] Figure 5 This is a graph obtained by plotting the diffraction intensity in the thickness direction and the in-plane direction of the carbon nanotube sheet according to one embodiment of the present invention relative to the reciprocal lattice vector g.

[0055] Figure 6 This is a cross-sectional transmission electron microscope (TEM) image of a carbon nanotube sheet according to one embodiment of the present invention.

[0056] Figure 7 This is a Fast Fourier Transform (FFT) image of a cross-sectional electron microscope image of a carbon nanotube sheet according to one embodiment of the present invention.

[0057] Figure 8 This is a graph obtained by plotting the brightness in the thickness direction and the brightness in the in-plane direction of a cross-sectional electron microscope image of a carbon nanotube sheet according to an embodiment of the present invention, relative to the pixel distance from the center.

[0058] Figure 9 This is a schematic diagram (cross-sectional view) illustrating the manufacturing process of a protective film, a protective film assembly frame, and a protective film assembly according to one embodiment of the present invention.

[0059] Figure 10 This is a schematic cross-sectional view of an EUV exposure apparatus 180, which is an example of an exposure apparatus in this embodiment.

[0060] Figure 11 This is a schematic diagram (cross-sectional view) illustrating the manufacturing process of the protective film, the protective film assembly frame, and the protective film assembly according to a variation of the present invention.

[0061] Figure 12 This is a schematic diagram (cross-sectional view) of a protective film assembly according to one embodiment of the present invention.

[0062] Figure 13 This is a selected area electron diffraction image of a cross-section of a carbon nanotube sheet according to an embodiment of the present invention.

[0063] Figure 14 These are scanning electron microscope images of carbon nanotube sheets according to embodiments of the present invention.

[0064] Figure 15 These are scanning electron microscope images of carbon nanotube sheets according to embodiments of the present invention.

[0065] Figure 16 This is a transmission electron microscope (TEM) image of a cross-section of a carbon nanotube sheet according to a comparative example of the present invention.

[0066] Figure 17This is a selected area electron diffraction image of a cross-section of a carbon nanotube sheet according to a comparative example of the present invention.

[0067] Figure 18 This is a Fast Fourier Transform (FFT) image of a cross-section of a carbon nanotube sheet according to a comparative example of the present invention, obtained using an electron microscope.

[0068] Figure 19 These are scanning electron microscope images of carbon nanotube sheets according to comparative examples of the present invention. Detailed Implementation

[0069] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the description of the embodiments illustrated below. Furthermore, in the drawings, to make the explanation clearer, the width, thickness, shape, etc. of each part are sometimes schematically shown compared to the actual form, but these are only examples and do not limit the interpretation of the present invention. In addition, in this specification and the drawings, the same elements as those described above are given the same reference numerals for the elements that have already appeared in the drawings, and detailed descriptions are sometimes appropriately omitted.

[0070] [definition]

[0071] In this specification, when a component or region is described as being "above (or below)" other components or regions, unless otherwise specified, it includes not only being located immediately above (or immediately below) other components or regions, but also being located above (or below) other components or regions, that is, including cases where other constituent elements are included between the component and other components or regions above (or below) it.

[0072] In this specification, EUV light refers to light with a wavelength of 5 nm to 30 nm. The wavelength of EUV light is preferably 5 nm to 14 nm.

[0073] In this specification, the term "protective film" refers to the thin film used in a protective film assembly. The protective film is preferably a self-supporting film. A self-supporting film is a film that can maintain its shape without a substrate or base material.

[0074] A protective film assembly refers to a protective film assembly having a protective film and a support frame supporting the protective film. A protective film assembly frame refers to a protective film assembly frame formed by connecting a first frame to the protective film. A protective film assembly also includes a protective film assembly formed by connecting a second frame to the protective film assembly frame. In this case, the first frame and the second frame function as a support frame supporting the protective film.

[0075] In this specification, "cutting" refers to cutting a substrate, or a substrate and a protective film formed thereon, into the desired shape of a protective film assembly. Since protective film assemblies are mostly rectangular, this specification shows examples of cutting into rectangles as specific examples of cutting.

[0076] In this specification, the process of removing a portion of the substrate while leaving the protective film is referred to as backetching. As an example of backetching, this specification shows an example of etching from the back side (the side of the substrate opposite to the side where the protective film is formed).

[0077] In this invention, the term "end" refers to a side surface, an edge, or a corner. Specifically, it includes: a substrate (or a first frame if the substrate is used as the first frame), an edge formed by the side surface of the support frame and the side surface; an edge formed by the upper surface of the substrate (the side in contact with the protective film) and the side surface; and a corner that is the area containing the point where the upper surface of the substrate intersects with the two side surfaces.

[0078] In this invention, a bundle is a bundle formed by multiple carbon nanotubes.

[0079] In the 2D diffraction image of the carbon nanotube sheet cross section in this invention, the direction along the film surface is defined as the in-plane direction, and the direction perpendicular to the in-plane direction is defined as the film thickness direction.

[0080] In this invention, the term "bundle oriented in-plane" means that the long axis of the carbon nanotube bundle is aligned with the in-plane direction of the carbon nanotube sheet. In other words, the length direction of the bundle is not upright along the thickness direction (Z-axis), but rather along the plane direction (XY direction). The length directions of the bundle do not need to be aligned side-by-side along the X-axis or Y-axis to form a mesh-like structure.

[0081] In this invention, the term "bundling" as "oriented along the film thickness direction" refers to the state in which the bundle of carbon nanotubes and the long axis of the carbon nanotubes are oriented towards the film thickness direction of the carbon nanotube sheet.

[0082] [Problems with the prior art discovered in this invention]

[0083] The protective film for EUV protective film components is typically manufactured by laminating SiN (silicon nitride) or similar materials onto a silicon wafer substrate. Furthermore, some EUV protective film components utilize carbon nanotube sheets in their protective films (Patent Document 1). However, Patent Document 2 describes a situation where increasing the density to achieve film strength results in lower transmittance; and that carbon nanotubes contain numerous impurities such as metals during manufacturing, leading to decreased transmittance.

[0084] Here, low purity of the carbon nanotube sheets means a high number of impurities, resulting in low EUV transmittance and easy absorption of EUV. Furthermore, if the protective film absorbs EUV, the energy of the EUV is converted into heat, causing the EUV-irradiated area to heat up to a high temperature, which in turn reduces the durability of the protective film. Therefore, low purity of the carbon nanotube sheets leads to a decrease in the strength and EUV transmittance of the protective film. The inventors have achieved a protective film with high EUV transmittance while using carbon nanotube sheets.

[0085] [Implementation Method 1]

[0086] use Figure 1 , Figure 2 , Figure 3 The manufacturing method of the protective film assembly 10 according to the present invention will be described. The protective film assembly 10 to be manufactured by the present invention is a protective film assembly for EUV lithography. First, on the substrate 100 ( Figure 1 (a), for example, on a silicon wafer, a protective film 102 is formed. Figure 1 (b) Figure 3 (S101). In this invention, carbon nanotube sheets as described below are used as protective film 102.

[0087] The carbon nanotubes (or monolithic carbon nanotube structures) used in the protective film 102 are formed on a chemical vapor deposition substrate by a CVD method (e.g., LP-CVD film formation, PE-CVD film formation, etc.) in which a metal catalyst is present in the reaction system and an oxidant is added in the reaction atmosphere. In this case, the oxidant can be water vapor, and the concentration of the water vapor can be between 10 ppm and 10,000 ppm. The water vapor can be added at a temperature between 600°C and 1000°C. Alternatively, the metal catalyst can be arranged or patterned on the chemical vapor deposition substrate to synthesize the film. Furthermore, the resulting carbon nanotubes can be a single layer or multiple layers, and can be carbon nanotubes erected along a direction perpendicular to the surface of the chemical vapor deposition substrate. Specifically, the super-growth method described, for example, in International Publication No. 2006 / 011655, can be used for manufacturing.

[0088] Carbon nanotube sheets are fabricated using carbon nanotubes (or monolithic carbon nanotube structures) obtained by exfoliating carbon nanotubes (or monolithic carbon nanotube structures) from a chemical vapor deposition substrate. The carbon nanotube sheets are deposited in the same manner as conventional carbon nanotube sheets. Specifically, a dispersion is used to disperse the obtained carbon nanotubes or monolithic carbon nanotube structures in a liquid.

[0089] The dispersion may contain a dispersant. If a dispersant is included, the bundles become finer and easier to orient in-plane, which is preferred. Types of dispersants that can be used include organic side-chain flavins, flavin derivatives, sodium lauryl sulfate, sodium cholate, sodium deoxycholate, and sodium dodecylbenzenesulfonate.

[0090] The type of solvent used as a dispersion can be appropriately selected based on the solubility of the dispersant. For example, when using an organic side-chain flavin as a dispersant, toluene, xylene, or ethylbenzene can be used as the solvent. When no dispersant is used, N-methylpyrrolidone (NMP), N,N-dimethylformamide, propylene glycol, or methyl isobutyl ketone (MIBK) can be used.

[0091] When carbon nanotubes are dispersed into fine and uniform bundles in a dispersion solution by super-growth, organic side-chain flavonoids are preferably used as dispersants.

[0092] The dispersion method can be selected appropriately. Ultrasonic dispersion, ball mills, roller mills, vibratory mills, mixers, jet mills, nanometer mills, etc., can be used.

[0093] After coating the dispersion onto the substrate 100, carbon nanotube sheets are formed on the substrate 100 by removing the liquid used in the dispersion. If a dispersion containing the carbon nanotubes of the present invention is coated onto the substrate, an evaporation process to remove the liquid from the dispersion yields a film in which the carbon nanotubes are substantially parallel to the substrate surface (i.e., excluding carbon nanotubes erected in a direction perpendicular to the substrate surface). Thus, carbon nanotube sheets are formed. The coating method is not particularly limited, and examples include spin coating, dip coating, rod coating, spray coating, and electrostatic spraying.

[0094] The carbon nanotube sheet formed on the substrate 100 by such operation is used as the protective film 102. The metal catalyst used in the formation of carbon nanotubes may be the cause of the reduction in EUV transmittance, but by peeling the carbon nanotubes from the chemical vapor growth substrate, it is possible to obtain a protective film 102 that contains almost no metal catalyst used in the formation of carbon nanotubes, which is therefore preferred.

[0095] A mask 104 is stacked on the side opposite to the side where the protective film is formed (the back side). Figure 1 (b)), then, remove the mask from the exposed area. Figure 1 (c)). Furthermore, by etching, the protective film 102 in the exposed area remains, removing a portion of the substrate. Figure 2 (a) Figure 3 (S103).

[0096] As a method for removing part of the substrate, back etching is employed. As described above, back etching is etching performed from the back side (the side of the substrate opposite to the side where the protective film is formed).

[0097] The substrate 100 may not be a silicon wafer substrate. The shape of the substrate is not limited to a perfect circle; it may also have oriented planes, notches, etc. Furthermore, the protective film may not be formed on the entire substrate. As for the substrate 100 for forming the protective film, it is preferable to use a material containing at least one of silicon, sapphire, and silicon carbide, which has a linear thermal expansion coefficient close to that of the protective film, rather than using aluminum alloys or the like used in ArF laser protective film assemblies, in order to reduce the thermal strain of the protective film assembly as a whole. Silicon is more preferred.

[0098] During the etching process, the goal can also be to simultaneously form a first frame 107 connected to the protective film 102, so that the silicon wafer outside the exposure area remains in a frame shape. Figure 2 (a)). In this case, the portion of the substrate that has not been removed is referred to as the first frame 107. By using the silicon wafer in a frame shape as the frame, the process of separately applying a protective film to the first frame can be omitted in manufacturing the protective film assembly frame.

[0099] The shape of the first frame is not particularly limited. From the viewpoint of increasing strength, it is possible to have a larger amount of substrate remaining as the first frame. Alternatively, other frames can be attached to the portion forming the first frame before etching, and etching can be performed in this state. Attaching other frames strengthens the first frame. For example, a second frame 108 can be used as one of the other frames. Furthermore, in subsequent processes, the second frame 108 can be further connected in addition to the first frame 107. Figure 2 (b) Figure 3 (S105). However, since the height of the protective film assembly is limited, it is preferable that the total height of the protective film and the support frame be less than 2.6 mm. A clamping hole may be provided on the separately connected second frame 108 for fixing the protective film assembly to the original plate 184 or for connecting to the first frame.

[0100] The shape, size, and material of the second frame 108 are not particularly limited. Preferably, the second frame 108 is made of a material with high resistance to EUV light, high flatness, and low ion leaching. Furthermore, since hydrogen gas is passed through the exposure apparatus to remove carbon contamination, it is preferably made of a material resistant to hydrogen free radicals. The material of the second frame 108 is not particularly limited and can be any material commonly used for the frame of the protective film assembly. Specifically, examples of materials for the second frame 108 include aluminum, aluminum alloys (5000 series, 6000 series, 7000 series, etc.), stainless steel, silicon, silicon alloys, iron, iron-based alloys, carbon steel, tool steel, ceramics, metal-ceramic composites, and resins. Aluminum and aluminum alloys are preferred from the perspectives of lightweight and rigidity. Furthermore, the second frame 108 may have a protective film on its surface.

[0101] In a protective film containing bundles of carbon nanotube sheets, the protective layer can be shaped like the bundles of the coated carbon nanotube sheets.

[0102] The protective membrane assembly can be manufactured by connecting the protective membrane assembly frame (a substance obtained by connecting the first frame and the protective membrane) to the second frame 108. Figure 2 (b)). The first frame 107 and the second frame 108 are support frames 109 that support the protective film, equivalent to frames with openings. Furthermore, the protective film assembly frame (the object obtained by connecting the first frame and the protective film) and the second frame 108 can be fixed with adhesive or connected with pins. That is, pin holes can be provided on the edges, sides, etc. of the protective film assembly frame, and pin holes can be provided at the positions of the overlapping second frame, and they can be connected with pins.

[0103] The protective film assembly 10 is connected to the original 184 during photolithography. Figure 2 (c) Figure 3 (S107).

[0104] The thickness of the aforementioned protective film 102 is less than 200 nm. The protective film includes carbon nanotube sheets, each carbon nanotube sheet having a bundle formed of multiple carbon nanotubes with a diameter of less than 100 nm, and the bundles are oriented in-plane within the carbon nanotube sheets.

[0105] Carbon nanotube sheets consist of bundles formed by multiple carbon nanotubes. The carbon nanotubes aggregate into bundles through van der Waals forces. This bundling allows for the formation of coarse fibrous structures, thus increasing strength compared to individual carbon nanotubes.

[0106] In this embodiment, the diameter of the bundles of carbon nanotubes in the carbon nanotube sheet needs to be 100 nm or less. This is because if the bundle diameter exceeds 100 nm, the film thickness increases in the overlapping areas, making it difficult to obtain a film with a thickness of 200 nm or less, and thus preventing the achievement of high EUV transmittance. Furthermore, the bundle diameter is more preferably 20 nm or less. This is because a finer bundle diameter results in a thinner film thickness in the overlapping areas, thereby enabling the acquisition of a protective film with high EUV transmittance.

[0107] The diameter of the bundle can be determined by the following steps.

[0108] 1) Use scanning electron microscope (SEM) images or atomic force microscope (AFM) images of a range (area) of 0.2μm×0.2μm to 2μm×2μm, taken at an observation magnification of 50,000x to 300,000x.

[0109] 2) Draw the outline of the bundle.

[0110] 3) Measure the vertical distance between two outlines belonging to the same bundle.

[0111] 4) The area near the junction of the bundle branch and the confluence is not counted as the bundle diameter.

[0112] 5) For two contour lines, use the graph where the tangents at the point where the bundle diameter is determined intersect or are parallel to each other at an angle of less than 15°.

[0113] 6) Draw a straight line from one end to the opposite end, and calculate the diameter of each bundle that the line crosses.

[0114] The bundles constituting the protective film are oriented along the in-plane direction of the film. Furthermore, in this invention, in the 2D diffraction pattern of the carbon nanotube sheet cross-section, the direction along the film surface is referred to as the in-plane direction, and the direction perpendicular to the in-plane direction is referred to as the film thickness direction.

[0115] When the bundles of carbon nanotubes and the direction of their long axes are aligned with the in-plane direction of the carbon nanotube sheet, it is called bundle orientation along the in-plane direction. Furthermore, when the bundles of carbon nanotubes and the direction of their long axes are aligned with the thickness direction of the carbon nanotube sheet, it is called bundle orientation along the thickness direction.

[0116] The orientation of the bundles can be examined using electron microscopy images and selected area electron diffraction images of the cross-section of the carbon nanotube sheets.

[0117] When the carbon nanotubes or bundles in a carbon nanotube sheet are oriented, anisotropy will appear in the diffraction pattern.

[0118] In cross-sectional electron microscopy images of carbon nanotube sheets in the range of 50 nm × 50 nm and above, the bundles are preferably oriented in the in-plane direction. In electron X-ray diffraction, the lattice spacing d is represented by the reciprocal of the reciprocal lattice vector g.

[0119] [Number 1]

[0120] d = 1 / g

[0121] The reciprocal lattice vector g can be obtained from the following formula using the distance L from the object (carbon nanotube sheet) to the detection surface of the microscope detector, the wavelength λ of the electron beam, and the distance r from the center of the film to the diffraction spot.

[0122] [Number 2]

[0123] g=r / λL

[0124] [Regarding the directionality of diffraction in carbon nanotubes]

[0125] In the selected area electron diffraction pattern of the carbon nanotube sheet cross-section, at d = 0.21 nm (g = 4.6 nm), which is equivalent to 3 / 2 times the C / C bond distance d of the unit lattice derived from the graphene sheet structure. 1 A peak appears at the position of ). In addition, since this diffraction peak originates from the unit lattice of the graphene sheet, it appears along the bundle of carbon nanotubes and the long axis of the carbon nanotubes.

[0126] Furthermore, at d = 0.37 nm (g = 2.7 nm - 1 Near 0.37 nm, a peak originating from the triangular lattice of carbon nanotube bundles appears. The intensity and scattering angle of this diffraction depend on the diameter and aggregation state of the nanotubes. In nanotube sheets using carbon nanotubes synthesized via the supergrowth method (SG method), the peak appears near d = 0.37 nm and exhibits a broad shape. Carbon nanotube sheets using carbon nanotubes synthesized via the eDIPS method have different diameters and distributions than SG-synthesized carbon nanotubes, resulting in different peak positions and shapes.

[0127] The diffraction peaks, which reflect the lattice of the bundled carbon nanotubes, i.e., the spacing between the bundles of carbon nanotubes, appear in a direction perpendicular to the bundles of carbon nanotubes and the long axis of the carbon nanotubes.

[0128] [The relationship between the orientation of carbon nanotube sheets and the anisotropy of diffraction peaks]

[0129] With the carbon nanotubes bundled and fully in-plane oriented, the unit lattice derived from the graphene sheet structure has a d = 0.21 nm (g = 4.6 nm). -1 The peak of ) appears strongly in the in-plane direction. On the other hand, the peak originating from the triangular lattice of carbon nanotubes is d = 0.37 nm (g = 2.7 nm). -1The peaks near the film thickness direction appear more strongly.

[0130] When carbon nanotubes are bundled and oriented irregularly along the in-plane and thickness directions, any diffraction peak will appear with equal intensity in both the in-plane and thickness directions.

[0131] With carbon nanotubes bundled and oriented perfectly perpendicular to the film surface, the unit lattice derived from the graphene sheet structure has a d = 0.21 nm (g = 4.6 nm). -1 The peak of ) appears strongly in the thickness direction of the film. On the other hand, the peak originating from the triangular lattice of the carbon nanotube bundles is d = 0.37 nm (g = 2.7 nm). -1 The peaks near the surface appear more strongly in the in-plane direction.

[0132] [Regarding the numerical representation of orientation when there is intermediate orientation]

[0133] By comparing and analyzing the intensity spectrum in the in-plane direction of the 2D electron diffraction image with the intensity spectrum in the film thickness direction, the degree of orientation can be determined. Figure 4 This is an example of a selected area electron beam diffraction image of a carbon nanotube sheet cross-section.

[0134] Figure 5 It is Figure 4 The diffraction intensity along the film thickness direction and the diffraction intensity in the in-plane direction are plotted relative to the reciprocal lattice vector g. Figure 5 The vertical axis represents brightness (relative brightness), which is obtained by representing the diffraction intensity of the diffraction image in gray levels ranging from 0 to 255. Diffraction intensity can be the detection intensity (arbitrary unit) of the electron microscope detector; alternatively, it can be the brightness (relative brightness) of the image obtained from the detector's detection intensity distribution, represented in gray levels, for example, from 0 to 255.

[0135] (Regarding the graphene sheet structure (g = 4.6 nm)) -1 (Definition of orientation)

[0136] Regarding the unit lattice derived from graphene sheet structure, d = 0.21 nm (g = 4.6 nm) -1 The diffraction peaks of the film are defined using the following formula: the ratio R of the peak intensity along the film thickness direction to the peak intensity along the in-plane direction. c-c .

[0137] [Number 3]

[0138]

[0139] here, and It is g = 4.6nm -1 and g = 5.0 nm -1 The diffraction intensity along the film thickness direction at that time. and This indicates that g = 4.6 nm -1 and g = 5.0 nm -1 The diffraction intensity in the in-plane direction at that time.

[0140] Given g = 5.0 nm -1 The reason for the difference in intensity at time is that, by comparing it with g = 4.6 nm -1 The non-overlapping peaks are subtracted from the intensity that forms the baseline, thus allowing the calculation of only the diffraction intensity originating from the unit lattice of the graphene sheet structure.

[0141] Furthermore, it is preferable to optimize the cumulative conditions during measurement and image contrast processing, etc., at g = 4.6 nm. -1 R is calculated under the condition of unsaturated diffraction intensity. c-c .

[0142] R c-c A value below 0.20 indicates in-plane orientation, while a value above 0.20 indicates no in-plane orientation.

[0143] R c-c The value is preferably 0.20 or less, more preferably 0.15 or less.

[0144] exist Figure 5 In the middle, R c-c With a value of 0.129, it exhibits strong in-plane orientation, making it a preferred choice for a protective film.

[0145] Regarding the bundle structure (g = 2.7 nm) -1 [Definition of orientation]

[0146] Regarding the triangular lattice of the bundle derived from carbon nanotubes, d = 0.37 nm (g = 2.7 nm). -1 The ratio R of the peak intensity in the thickness direction to the peak intensity in the in-plane direction is defined using the following formula. B .

[0147] [Number 4]

[0148]

[0149] here, and This indicates that g = 2.7 nm -1 and g = 2.2nm -1 The diffraction intensity along the film thickness direction at that time. and This indicates that g = 2.7 nm-1 and g = 2.2nm -1 The in-plane diffraction intensity at time g = 2.7 nm. -1 yes Figure 5 The value of g that forms the peak of diffraction intensity is g = 2.2 nm. -1 It is used to subtract the intensity that becomes the baseline from the position where it does not overlap with the diffraction peak.

[0150] Furthermore, it is preferable to optimize the cumulative conditions during measurement and image contrast processing, etc., at g = 2.7 nm. -1 Or, g = 2.2 nm could become the baseline. -1 R is calculated under the condition of unsaturated diffraction intensity. B .

[0151] Calculate R B The value of g at that time is not limited to 2.7 nm. -1 2.2nm -1 It is possible to select the appropriate value. It is particularly preferred to use the value of g when the peak position is at its maximum, and the value of g at the position that can be subtracted to become the baseline at the position that does not overlap with the diffraction peak.

[0152] In the case of random orientation, the diffraction intensity in the in-plane direction and the film thickness direction becomes equal, but and The sign is reversed, so it becomes R. B =-1. In Increase and become At that time, R B Take a positive value. The stronger the in-plane orientation, the higher the value of R. B The larger the value, the more positive the value.

[0153] R B A value of 0.40 or higher indicates in-plane orientation, while a value less than 0.40 indicates no in-plane orientation. B The value is preferably 0.40 or higher, more preferably 0.6 or higher. Figure 5 In the middle, R B With a value of 1.02, the bundle exhibits strong in-plane orientation, making it a preferred material for protective films.

[0154] [Orientation analysis of cross-sectional electron microscope images via Fast Fourier Transform (FFT)]

[0155] Furthermore, the degree of in-plane orientation of the protective film can be examined using the Fast Fourier Transform (FFT) of the cross-sectional electron microscope image. When in-plane orientation is achieved, it is preferable that a high-intensity striped pattern can be observed in the FFT image along the axis from the center along the film thickness direction.

[0156] Figure 6 and Figure 7 These are TEM and FFT images of a cross-section of a bundled carbon nanotube sheet with in-plane orientation. A high-intensity striped pattern can be observed along the thickness axis from the center.

[0157] Figure 8 It is Figure 7 The images are obtained by plotting the brightness in the thickness direction and the brightness in the in-plane direction relative to the pixel distance from the center.

[0158] Figure 8 The vertical axis represents brightness (relative brightness), which is obtained by representing the FFT image in grayscale levels ranging from 0 to 255. There is no particular restriction on the unit of brightness in the FFT image; for example, brightness (relative brightness) represented in grayscale levels ranging from 0 to 255 can be used.

[0159] The ratio R of the total luminance in the in-plane direction to the total luminance in the film thickness direction is defined by the following formula. FFT .

[0160] [Number 5]

[0161]

[0162] here, and This represents the brightness in the in-plane and thickness directions at a distance of the i-th pixel from the center. and This refers to the baseline brightness located far from the center. Figure 8 middle, and In the range of 450 to 500 pixels, the brightness (relative brightness) is 45 when using grayscale representation with a value range of 256 levels from 0 to 255.

[0163] R FFT A value below 0.60 indicates in-plane orientation, while a value above 0.60 indicates no in-plane orientation. R FFT The value is preferably below 0.60. Figure 8 In the middle, R FFT With a value of 0.519, the bundle is in-plane oriented, making it a preferred material for protective films.

[0164] Bundled carbon nanotube sheets with in-plane orientation can be made to have a film thickness equal to the bundle diameter, achieving high EUV transmittance. Furthermore, bundled carbon nanotube sheets (or protective films) with in-plane orientation can be made into a mesh structure in which the bundles are intertwined in the in-plane direction, thus enabling the formation of self-supporting films even with thicknesses below 100 nm.

[0165] Carbon nanotube sheets (or protective films) have a network structure in which bundles of nanotubes are intertwined. This network structure can be observed using SEM or AFM images taken at magnifications of 50,000x to 300,000x, with a size ranging from 0.2μm × 0.2μm to 2μm × 2μm. In SEM and AFM images, points where three or more bundles are connected are considered the connection points of the bundles. The network structure consists of the straight portions of the bundles, the connection points, and the interstitial structures that do not contain them.

[0166] For carbon nanotube sheets with a mesh structure that have been oriented in-plane, when stress is applied to the sheet, the deformation and parallel movement of the bundles can be suppressed while the stress is dispersed. Therefore, even when stress is applied to the self-supporting membrane, the mesh structure and the shape of the self-supporting membrane can be maintained.

[0167] The aforementioned protective film 102 comprises carbon nanotube sheets, which contain carbon nanotubes. During the synthesis of carbon nanotubes, light elements other than carbon, such as metal catalysts and oxygen, are mixed in as impurities. Here, light elements refer to elements with atomic numbers less than 18 (argon).

[0168] The carbon content in the carbon nanotubes of the aforementioned protective film 102 is 98% by mass or more. As the aforementioned protective film, carbon nanotubes synthesized, for example, by methods described in international publications such as International Publication No. 2006 / 011655 can be used. The amount of metal contained in the carbon nanotubes can be determined by fluorescence X-ray diffraction. Furthermore, carbon nanotubes from which the metal catalyst has been removed by acid washing can be used. Because the purity of the carbon nanotube sheet (the carbon content in the carbon nanotube sheet) is very high (98% by mass or more), the EUV transmittance is high. Moreover, due to the high EUV transmittance, the protective film assembly exhibits excellent durability against EUV. The amount of light elements such as oxygen contained in the carbon nanotubes can be determined by XPS.

[0169] Furthermore, in this invention, the carbon nanotubes in the protective film 102 have a length of 10 μm to 10 cm and a diameter of 0.8 nm to 6 nm. Alternatively, the center dimension of the carbon nanotube diameter is 1 nm to 4 nm, the length of the carbon nanotube is 10 μm to 10 cm, and the carbon content in the carbon nanotube is 98% by mass or more. In this specification, the center dimension of the carbon nanotube diameter is determined as follows: A transmission electron microscope (TEM) is used to capture a transmission electron image of the carbon nanotube sheet. The outer diameter, i.e., the diameter of the carbon nanotube, is measured from the TEM image. A histogram is created based on the measured data, and the diameter of 90% of the carbon nanotubes is calculated from the histogram. Therefore, the so-called center dimension of the carbon nanotube diameter being 1 nm to 4 nm means that 90% of the carbon nanotubes in the film have a diameter of 1 nm to 4 nm, and the diameter of the remaining 10% of the carbon nanotubes does not need to be in the range of 1 nm to 4 nm.

[0170] In this invention, due to the long length of the carbon nanotubes (10 μm to 10 cm), they intertwine to form a strong and tough film (sheet). Furthermore, the large diameter of the carbon nanotubes (0.8 nm to 6 nm, or a central diameter of 1 nm to 4 nm) results in a low-density film with high EUV transmittance. Based on these characteristics, the high EUV transmittance leads to high heat resistance and excellent durability against EUV. The film itself also possesses high physical strength, thus achieving film strength capable of withstanding atmospheric pressure to vacuum processes in the manufacturing of protective film components and EUV exposure systems.

[0171] Furthermore, in this invention, within the aforementioned ranges of carbon nanotube diameter and length, the ratio of the carbon nanotube's length to its diameter (length / diameter) is preferably 1 × 10⁻⁶. 4 Above 1×10 8 Below. By being within such a range, EUV transmittance and film strength can be further improved.

[0172] [Implementation Method 2]

[0173] Embodiment 2 is a method of using a chemical vapor deposition substrate for forming the protective film 102 using carbon nanotubes via CVD as the substrate 100.

[0174] Since the resulting carbon nanotube film consists of carbon nanotubes erected perpendicular to the substrate surface, various methods can be employed to physically push down the erected carbon nanotubes: preparing other substrates and physically pushing down the erected carbon nanotubes by immersing the carbon nanotube film in a liquid, physically pushing down the erected carbon nanotubes by injecting liquid into the carbon nanotube film, or pushing down the erected carbon nanotubes horizontally by peeling off the generated carbon nanotube structure and sandwiching it between two substrates. In this invention, a carbon nanotube sheet with carbon nanotubes (or carbon nanotube structures) substantially parallel to the substrate surface is used as the protective film 102.

[0175] Except as described above, it is the same as in Implementation 1.

[0176] [Implementation Method 3]

[0177] Implementation method 3 is a method in which the protective film 202 is supported by the support frame 209 instead of using the first frame and the second frame as support frames. Figure 12 This invention relates to a method for manufacturing the protective film assembly 20.

[0178] Carbon nanotubes (which can be monolithic carbon nanotube structures) are formed on chemical vapor deposition (CVD) substrates such as silicon wafers, glass, metals, and polymer films. The resulting carbon nanotubes are then floated on the surface of a liquid such as water or an organic solvent, thereby peeling them off from the CVD substrate. The floating carbon nanotube film is then scooped out of the liquid surface using a support frame coated with an adhesive, thus fixing it to the support frame. The resulting carbon nanotube film becomes a protective film 202.

[0179] As a method for obtaining a self-supporting membrane by floating it on a liquid and then retrieving it, transfer techniques using graphene or similar materials can be employed. For example, when retrieving a membrane of carbon nanotubes floating on the surface of a liquid, the membrane can be retrieved by supporting it with a substrate such as a polymer film while simultaneously fixing it with a support frame coated with an adhesive. Carbon nanotube sheets can be obtained by removing the substrate such as the polymer film through etching.

[0180] When the integral carbon nanotube structure formed on the chemical vapor deposition substrate has sufficient strength as a film, it can be mechanically peeled off from the chemical vapor deposition substrate to serve as a protective film 202. The method for supporting the protective film 202 with the support frame 209 is not particularly limited, and the same method as conventional protective film assemblies can be used.

[0181] The metal catalyst used in the formation of carbon nanotubes may be the cause of the reduced EUV transmittance, but it is preferable to obtain a protective film 202 that contains almost no metal catalyst used in the formation of carbon nanotubes by peeling carbon nanotubes off the substrate for chemical vapor growth.

[0182] There are no particular limitations on the shape, size, or material of the support frame 209. The same material as the second frame can be used as the support frame 209.

[0183] [Protective Layer]

[0184] For protective films used in EUV lithography, since hydrogen radical resistance (i.e., reduction resistance) and oxidation resistance are required, a protective layer can be provided to protect carbon nanotubes from the effects of hydrogen radicals and oxidation. The protective layer 106 can be provided in contact with the carbon nanotube sheet. For example, it can be provided on the surface of the protective films 102 and 202 on the substrate 184 side, or it can be provided between the protective film 102 and the substrate 100. Figure 9 (a)) It can also be laminated on the protective films 102 and 202 as the top layer, or they can be combined. Hydrogen radicals can be generated on both sides of the protective films, so it is preferable to combine the above, that is, to form the protective layer 106 on the original 184 side of the protective films 102 and 202, and further laminate it on the protective films 102 and 202 as the top layer.

[0185] Figure 9 The diagram shows a protective film assembly with the protective layer 106 disposed on the surface of the original 184 side of the protective films 102 and 202. Figure 9 (b) and a diagram showing the connection between the original 184 and the protective film assembly 10 when the protective layer 106 is disposed between the protective film 102 and the substrate 100. Figure 9 (c)). The protective layer 106 can be selected from SiO2. x (x≤2), Si a N b (a / b is 0.7 to 1.5), SiON, Y2O3, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, B4C, SiC or Rh.

[0186] To avoid impairing EUV light transmission, the thickness of the protective layer is preferably between 1 nm and 10 nm, and more preferably between 2 nm and 5 nm. By setting the thickness of the protective layer to between 1 nm and 10 nm, the absorption of EUV light by the protective layer can be suppressed, thereby preventing a decrease in transmittance.

[0187] The ratio of the thickness of the protective layer to the thickness of the protective film is preferably in the range of 0.03 to 1.0. If it is within the above range, the absorption of EUV light by the protective layer can be suppressed, and the decrease in transmittance can be suppressed.

[0188] Furthermore, if protective layers are stacked, EUV light reflection may occur at the newly formed layer interfaces—the interface between the protective layer and air, and the interface between the protective layer and the protective film—resulting in reduced transmittance. The EUV light reflectance at these layer interfaces can be calculated based on the thickness of the protective film and the protective layer, as well as the types of elements constituting them. Moreover, similar to the principle of antireflective films, reflectance can be reduced by optimizing the film thickness.

[0189] Regarding the thickness of the protective layer, the optimal thickness is preferably set within a range that suppresses the reduction in EUV light transmittance caused by absorption and the reduction in EUV light transmittance caused by reflection, while also preventing oxidation and reduction. There are no particular limitations on the thickness uniformity or surface roughness of the protective layer. During the pattern formation process of EUV exposure, as long as there are no non-uniformities in film thickness, non-uniformities in transmittance due to surface roughness, or obstacles caused by EUV light scattering, the protective layer can be either a continuous layer or an island-like structure. Furthermore, the film thickness can be non-uniform, and the surface roughness can also be present.

[0190] The average refractive index of the protective film, in which the protective film and the protective layer are bonded together, is preferably in the range of 1.1 to 3.0. The refractive index can be measured by methods such as spectroelliptic photometry. Furthermore, the average density of the protective film, in which the protective film and the protective layer are bonded together, is preferably 0.1 g / cm³. 3 The above 2.2g / cm 3 The following range. Density can be determined using methods such as X-ray reflectance analysis.

[0191] The thickness of the protective film (total thickness when it consists of two or more layers) can be set, for example, to be 10 nm to 200 nm, preferably 10 nm to 100 nm, more preferably 10 nm to 70 nm, particularly preferably 10 nm to 50 nm, and even more preferably 10 nm to 30 nm. The thinner the film, the higher the EUV transmittance can be obtained.

[0192] The thickness of the protective film can be determined by the following method: The protective film is transferred onto the substrate, at a thickness of 100 μm. 2 Above 1000μm 2 The following area was measured using AFM. The measurement area includes both the substrate surface and the film. At 10 μm... 2 For the areas mentioned above, the average height of the substrate and the film are measured respectively, and the film thickness is calculated from the difference between the average thickness of the substrate and the film.

[0193] The protective film preferably has high EUV light transmittance, and more preferably, the transmittance of the light used in EUV lithography (e.g., light with a wavelength of 13.5 nm or 6.75 nm) is 50% or more, even more preferably 80% or more, and still more preferably 90% or more. When the protective film and the protective layer are laminated, the light transmittance of the film containing them is preferably 50% or more.

[0194] (EUV resistance evaluation of protective film)

[0195] EUV resistance can be evaluated by irradiating the protective film with EUV light and performing various analyses on the irradiated and unirradiated portions. Methods used include compositional analysis such as XPS, EDS, and RBS; structural analysis methods such as XPS, EELS, IR, and Raman spectroscopy; film thickness evaluation methods such as ellipsometry, interferometric spectroscopy, and X-ray reflectance analysis; and appearance and surface shape evaluation methods such as microscopic observation, SEM, and AFM. Heat dissipation can be studied in more detail by combining analytical results obtained from computer simulations.

[0196] Regarding protective films, the durability evaluation of protective films can be carried out by appropriately selecting methods such as vacuum ultraviolet irradiation, ultraviolet-visible light irradiation, infrared irradiation, electron beam irradiation, plasma irradiation, and heat treatment, depending on the evaluation items, and is not limited to EUV light.

[0197] When a protective layer is provided, the evaluation can be performed using a protective film that combines the protective film and the protective layer.

[0198] [Evaluation of the membrane strength of the protective film]

[0199] One method for evaluating the strength of a protective membrane is the evaluation method using a nano indenter. Other methods for evaluating membrane strength include the resonance method, the expansion test method, the evaluation method for the presence or absence of membrane rupture caused by air blowing, the evaluation method for the presence or absence of membrane rupture caused by vibration testing, and the tensile strength test of the protective membrane using a tensile testing device.

[0200] When a protective layer is provided, the evaluation can be performed using a protective film that combines the protective film and the protective layer.

[0201] [Film adhesive layer]

[0202] The membrane adhesive layer is used to bond the support frame 209 and the protective film 202 when they are manufactured separately. The membrane adhesive layer can be, for example, a layer formed from acrylic resin adhesives, epoxy resin adhesives, polyimide resin adhesives, silicone resin adhesives, inorganic adhesives, etc. From the viewpoint of maintaining the vacuum level during EUV exposure, the membrane adhesive layer is preferably a membrane adhesive layer with low gas release. As a method for evaluating gas release, a gas analysis device, such as a temperature-induced gas separation analyzer, can be used.

[0203] Furthermore, there are no particular restrictions on the method of fixing the protective film to the support frame. The protective film can be directly pasted to the support frame, or it can be fixed by a film adhesive layer located on one end face of the support frame. Alternatively, it can be fixed to the support frame by mechanical fixing methods, the attraction of magnets, etc.

[0204] As a method for evaluating the adhesion between the protective membrane and the support frame, methods such as changing pressure, area, distance, and angle to evaluate the presence or absence of membrane rupture and peeling through air blowing, or changing acceleration and amplitude to evaluate the presence or absence of membrane rupture and peeling through vibration testing, can be used.

[0205] [Original version uses adhesive layer]

[0206] The original adhesive layer is used to bond the protective film assembly to the original substrate. This original adhesive layer can be located at the end of the protective film assembly on the side where the protective film is not laid. Examples of original adhesive layers include double-sided adhesive tape, silicone adhesives, acrylic adhesives, polyolefin adhesives, and inorganic adhesives. From the viewpoint of maintaining the vacuum level during EUV exposure, an original adhesive layer with minimal gas release is preferred. As a method for evaluating gas release, a gas analysis device, such as a temperature-controlled gas separation analyzer, can be used.

[0207] Since the adhesive layer for the film and the adhesive layer for the original substrate are exposed to scattered EUV light within the EUV exposure apparatus, EUV resistance is preferred. If EUV resistance is low, the adhesiveness and strength of the adhesive will decrease during EUV exposure, leading to adhesive peeling and foreign matter formation within the exposure apparatus. EUV irradiation resistance can be evaluated using methods such as compositional analysis (XPS, EDS, RBS, etc.); structural analysis (XPS, EELS, IR, Raman spectroscopy, etc.); film thickness evaluation (ellipsometry, interferometry, X-ray reflectance, etc.); appearance and surface shape evaluation (microscopic observation, SEM, AFM, etc.); and strength and adhesion evaluation (using nanoindenters, peel tests, etc.).

[0208] In photolithography, accurate transfer of circuit patterns is required. Therefore, the transmittance of the exposed light needs to be substantially uniform within the exposure range. By using the protective film of this embodiment, a protective film assembly with a fixed transmittance within the exposure range can be obtained.

[0209] [Applications of protective membrane components]

[0210] The protective film assembly of the present invention can serve not only as a protective member for preventing foreign matter from adhering to the original plate within an EUV exposure apparatus, but also as a protective member for protecting the original plate during storage and handling. For example, if the original plate is exposed with the protective film assembly installed, it can be directly stored after being removed from the EUV exposure apparatus. Methods for installing the protective film assembly onto the original plate include adhesive bonding, electrostatic adsorption, and mechanical fixing.

[0211] [Original version exposed]

[0212] The original exposure in this embodiment includes the original and the protective film assembly of this embodiment installed on the original.

[0213] The original exposure of this embodiment has the protective film assembly of this embodiment, and therefore performs the same effect as the protective film assembly of this embodiment.

[0214] There are no particular limitations on the method for installing the original plate in the protective film assembly of this embodiment. For example, the original plate can be directly pasted to the support frame, or it can be fixed by an adhesive layer on the original plate located on one end face of the support frame, or the original plate can be fixed to the support frame by mechanical fixing, attraction of magnets, etc.

[0215] Here, as a prototype, a prototype comprising a support substrate, a reflective layer stacked on the support substrate, and an absorber layer formed on the reflective layer can be used. By absorbing a portion of the EUV light through the absorber layer, the desired image is formed on a sensing substrate (e.g., a semiconductor substrate with a photoresist film). The reflective layer can be a multilayer film of molybdenum (Mo) and silicon (Si). The absorber layer can be a material with high absorption of EUV light, such as chromium (Cr) or tantalum nitride.

[0216] [Exposure device]

[0217] The exposure apparatus of this embodiment has the same exposure master as that of this embodiment. Therefore, it achieves the same effect as the exposure master of this embodiment.

[0218] The exposure apparatus of this embodiment preferably includes a light source that emits exposure light (preferably EUV light, more preferably EUV light; the same applies hereinafter), an exposure master plate of this embodiment, and an optical system that guides the exposure light emitted from the light source to the exposure master plate. The exposure master plate is configured such that the exposure light emitted from the light source passes through a protective film and illuminates the master plate.

[0219] According to this method, in addition to being able to form miniaturized patterns (e.g., linewidth below 32nm) using EUV light, even when using EUV light where image resolution defects caused by foreign objects are prone to become a problem, pattern exposure with reduced image resolution defects caused by foreign objects can be performed.

[0220] [Semiconductor device manufacturing method]

[0221] The semiconductor device manufacturing method of this embodiment includes the following steps: irradiating the original exposure plate with exposure light emitted from a light source through the protective film of the original exposure plate of this embodiment, and reflecting the light onto the original exposure plate; and irradiating the sensing substrate with exposure light reflected by the original exposure plate through the protective film to expose the sensing substrate into a pattern.

[0222] According to the semiconductor device manufacturing method of this embodiment, it is possible to manufacture a semiconductor device in which the image defects caused by foreign objects are reduced even when EUV light, which is prone to image defects caused by foreign objects, is used.

[0223] Figure 10 This is a schematic cross-sectional view of an EUV exposure apparatus 180, which is an example of an exposure apparatus in this embodiment.

[0224] like Figure 10 As shown, the EUV exposure apparatus 180 includes: a light source 182 that emits EUV light, an exposure master 181 which is an example of an exposure master in this embodiment, and an illumination optical system 183 that guides the EUV light emitted from the light source 182 to the exposure master 181.

[0225] The original exposure 181 includes a protective film assembly 10 comprising a protective film 102 and a support frame, and an original exposure 184. The original exposure 181 is configured such that EUV light emitted from the light source 182 passes through the protective film 102 and illuminates the original exposure 184.

[0226] The original 184 reflects the EUV light it is irradiated into a pattern.

[0227] The protective film 102 and the protective film assembly 10 are examples of the protective film and protective film assembly of this embodiment, respectively.

[0228] In the EUV exposure apparatus 180, filter windows 185 and 186 are respectively provided between the light source 182 and the illumination optical system 183, and between the illumination optical system 183 and the original 184.

[0229] In addition, the EUV exposure apparatus 180 includes a projection optics system 188 that guides EUV light reflected from the original 184 to the sensing substrate 187.

[0230] In the EUV exposure apparatus 180, EUV light reflected by the original image 184 is guided onto the sensing substrate 187 via the projection optics system 188, and the sensing substrate 187 is exposed to form a pattern. Furthermore, the EUV exposure is performed under reduced pressure conditions.

[0231] EUV light source 182 emits EUV light toward illumination optics system 183.

[0232] EUV light source 182 includes a target and a pulsed laser irradiation unit. By irradiating the target with a pulsed laser, plasma is generated, thereby obtaining EUV. If the target is Xe, EUV with wavelengths between 13 nm and 14 nm can be obtained. The wavelength of the light emitted by the EUV light source is not limited to the range of 13 nm to 14 nm; any wavelength suitable for the purpose, within the range of 5 nm to 30 nm, is acceptable.

[0233] The illumination optics system 183 focuses the light emitted from the EUV light source 182 to homogenize the illuminance and illuminate the original 184.

[0234] The illumination optical system 183 includes multiple multilayer mirrors 189 for adjusting the optical path of EUV, and an optical coupler (optical integrator). The multilayer mirrors are multilayer films obtained by alternating layers of molybdenum (Mo) and silicon (Si).

[0235] There are no particular restrictions on the installation method of filter windows 185 and 186. Examples include methods such as pasting with adhesives or mechanically fixing them inside the EUV exposure device.

[0236] A filter window 185 disposed between the light source 182 and the illumination optical system 183 captures stray particles (fragments) generated by the light source to prevent stray particles (fragments) from adhering to components (e.g., multilayer mirrors 189) inside the illumination optical system 183.

[0237] On the other hand, a filter window 186 configured between the illumination optics system 183 and the original 184 captures particles (fragments) flying off from the light source 182 side to prevent the flying particles (fragments) from adhering to the original 184.

[0238] Furthermore, foreign matter adhering to the original wafer can cause EUV light absorption or scattering, leading to poor image resolution on the wafer. Therefore, the protective film assembly 10 is installed to cover the EUV light irradiation area of ​​the original wafer 184. EUV light passes through the protective film 102 and irradiates the original wafer 184.

[0239] EUV light reflected by the original 184 passes through the protective film 102 and is projected onto the sensing substrate 187 by the projection optical system 188.

[0240] The projection optical system 188 focuses the light reflected from the original image 184 onto the sensing substrate 187. The projection optical system 188 includes multiple multilayer mirrors 190, 191, etc., for adjusting the light path of EUV.

[0241] The sensing substrate 187 is a substrate such as a semiconductor wafer coated with a photoresist. The photoresist is cured into a pattern by EUV reflected by the original substrate 184. By developing the photoresist, the semiconductor wafer is etched, thereby forming the desired pattern on the semiconductor wafer.

[0242] Furthermore, the protective film assembly 10 is mounted on the original plate 184 via an adhesive layer or the like. Foreign matter adhering to the original plate causes EUV absorption or scattering, resulting in poor image resolution on the wafer. Therefore, the protective film assembly 10 is mounted to cover the EUV irradiation area of ​​the original plate 184, allowing EUV to pass through the protective film 102 and irradiate the original plate 184.

[0243] As for the method of installing the protective film assembly 10 onto the original plate 184, any method that can prevent foreign objects from adhering to the surface of the original plate is acceptable. Examples include methods such as pasting the protective film assembly 10 to the original plate 184 with adhesive, electrostatic adsorption, and mechanical fixing. There are no particular limitations. The method of pasting with adhesive is preferred.

[0244] [Variation Example 1]

[0245] This invention may include a process for removing particles. Examples of methods for removing particles include, but are not limited to, wet washing, mechanical washing, and dry washing. Examples of wet washing include RCA washing with SC1 and SC2 washing. SC1 washing removes particles generated by ammonia and hydrogen peroxide, while SC2 washing removes heavy metals generated by hydrochloric acid and hydrogen peroxide. Washing with pure water or organic solvents is also possible. Furthermore, washing with sulfuric acid and hydrogen peroxide (a mixture of sulfuric acid and hydrogen peroxide), buffered hydrofluoric acid (a mixture of hydrofluoric acid and ammonium fluoride), or hydrofluoric acid can be performed. Washing methods can be combined in any order. Dry washing methods include polishing with O2 plasma and argon sputtering.

[0246] [Variation Example 2]

[0247] In this invention, chamfering can be performed at at least one location on the substrate, support frame, first frame, and second frame. In this specification, chamfering encompasses both R-surface and C-surface processing. R-surface processing refers to forming a curved portion by processing at least one end (side, edge, or corner, etc.) of the substrate, support frame, first frame (including a first frame obtained by etching back the substrate), and second frame. C-surface processing, as used in this specification, refers to cutting the aforementioned at least one end at an angle (100 degrees to 170 degrees). By performing such processing, sharp portions (acute angles) are removed, reducing the likelihood of fragmentation during transport and handling after manufacturing, even if it collides with certain components.

[0248] [Variation Example 3]

[0249] In this invention, one or more holes can be opened on the substrate 100. Figure 11 ). Figure 11 (a)~ Figure 11 (c) is a diagram showing holes 130 formed in four directions on the substrate. Figure 11 (a) is a top view. Figure 11 (b) and Figure 11 (c) is a top view. Figure 11 (a) Cross-sectional view between A and A'. (See diagram below.) Figure 11 As shown in (b), one or more holes 130 can be opened in the protective film 102 on the formed substrate 100. Figure 11 (b) In this way, the hole does not have to penetrate the substrate. Of course, it can also be like... Figure 11 As shown in (c), it penetrates the substrate. Figure 11 (b) and Figure 11 (c) In this manner, holes can be formed in the protective film and the substrate. When a hole penetrating the substrate is provided and etching is selected as the cutting process, or when back etching is performed, to protect the hole, a process can be provided to protect the hole portion using a photoresist, etc. The size of the hole 130 is not limited; for example, if the hole is approximately circular, a hole with a diameter of approximately 50 μm to 2000 μm can be opened. A hole with a diameter of approximately 200 μm to 700 μm is preferred. Furthermore, the shape of the hole 130 is not particularly limited and can be polygonal (e.g., approximately quadrilateral). In the case of an approximately quadrilateral, the length of one side is not limited; holes with a long side length of 100 μm to 3000 μm and a short side length of 50 μm to 1000 μm can be opened. The long side length is preferably 150 μm to 2000 μm, and the short side length is preferably 100 μm to 700 μm. Figure 11 As shown in (a), the hole 130 can be disposed on the side of the protective film assembly, but the location of the hole is not limited. The hole 130 can be used as a clamping hole or a vent for mounting or removing the protective film from a photomask. As a protective film assembly, the hole is not a necessary component.

[0250] Hole 130 is formed by ultra-short pulse laser, other lasers, etching, etc. When forming with a laser, from the viewpoint of producing a high-quality protective film with minimal dust, it is preferable to use an ultra-short pulse laser (e.g., picosecond laser, nanosecond laser) that reduces debris during processing. However, the hole can be formed simultaneously with etching during the substrate's back etching process (described later) instead of at this stage, thus simplifying the process. That is, hole formation and etching are performed concurrently after trimming. Conditions for using a nanosecond laser can be set as follows: repetitive vibration frequency of 5 kHz to 15 kHz, pulse energy of 5 W to 15 W, scanning speed of 5 mm to 30 mm per second, and number of scans of 40 to 300 times, but are not limited to these. Furthermore, when processing with an ultra-short pulse laser, a laser slag adsorption prevention agent can be used. For example, an agent such as CBX mixed with micrographite in isopropyl alcohol (IPA) can be applied to the substrate before hole formation, but is not limited to this. When a scum adhesion inhibitor is used, it is removed by washing after the hole is formed. Other methods to prevent scum adhesion include laser processing while simultaneously injecting helium gas onto the substrate to suppress scum adhesion.

[0251] [Variation Example 4]

[0252] In addition, such as Figure 11 As shown in (d), as a cutting method with less dust, adhesive sheets 112, which are elastic and whose adhesion decreases when subjected to external stimuli, are adhered to both sides of the substrate. A bridge 124 is then formed inside the substrate where the adhesive sheets are attached. A cut is then made in this bridge 124 to perform the cutting. Alternatively, in this invention, only the substrate may be cut, or the protective film formed on the substrate may be cut along with the substrate.

[0253] As an example of cutting, it can be cut into, for example, a rectangular shape, but the cutting shape is not limited and can be processed into any shape. Furthermore, the cutting method is not limited. Methods such as mechanically applying force to cut the protective film and substrate can be used, as well as laser cutting, laser semi-cutting (stealth cutting), blade cutting, sandblasting, anisotropic etching, and dry etching. However, methods that minimize dust generation from foreign particles during cutting are preferred. Additionally, although the protective film cannot be washed after etching back due to its extremely thin thickness, if a dust-generating process such as the cutting step is performed before etching back, washing can be performed before etching back, enabling the production of protective films, protective film assembly frames, and protective film assemblies with less dust.

[0254] Example

[0255] (Example 1)

[0256] 300 mg of carbon nanotubes (diameter ≥ 3 nm ≤ 5 nm, length ≥ 100 μm ≤ 600 μm, carbon content ≥ 99%) synthesized using the method described in International Publication No. 2006 / 011655, and 1 g of an organic side-chain flavin as a dispersant, were added to 100 mL of toluene. The mixture was stirred with a magnetic stirrer at approximately 480 rpm for 2 hours, followed by ultrasonic dispersion of the suspension at 40% output using a probe homogenizer for a total of 2 hours. During this period, the mixture was ice-cooled for 5 minutes every 20 minutes. The resulting carbon nanotube dispersion was then degassed.

[0257] A dispersion was applied to a silicon substrate using a scraper. The distance between the scraper and the silicon substrate was 240 μm. After drying, a film with a thickness of 200 nm was obtained. After removing the organic side-chain flavin with chloroform, the carbon nanotube sheet film was peeled off by immersing the silicon substrate in a water bath. The film was then retrieved using a frame to obtain a protective film serving as a self-supporting membrane.

[0258] The cross-sectional electron microscope image of the obtained protective film ( Figure 6 ), observing the in-plane orientation of the entire region bound to the membrane. This was achieved using selected area electron diffraction (SED) images. Figure 13 At d = 0.21 nm and 0.12 nm, the intensity of the two loops originating from carbon-carbon bonds within the carbon nanotubes was weak in the thickness direction, indicating that the loops were broken. In addition, at d = 0.37 nm, wide spots originating from the triangular lattice structure of the bundle appeared side by side in the thickness direction. Anisotropy of scattering intensity was observed in both the thickness direction and the in-plane direction.

[0259] Figure 5 This is a graph obtained by plotting the diffraction intensity in the thickness direction and the diffraction intensity in the in-plane direction relative to the reciprocal lattice vector g. Figure 5 The obtained R c-c R is 0.129. BThe value is 1.02. This indicates that the bundles formed by carbon nanotubes exhibit strong orientation.

[0260] FFT images of cross-sectional electron microscopy images ( Figure 7 In the film, a high-intensity striped pattern was observed along the thickness axis from the center, confirming the orientation in the in-plane direction.

[0261] Figure 8 It is a graph obtained by plotting the brightness in the thickness direction and the brightness in the in-plane direction of the FFT image relative to the pixel distance from the center. R FFT The value was 0.519, confirming that the bundle underwent in-plane orientation. This was confirmed by the SEM image ( Figure 14 The average diameter of the bundles was found to be 9.0 nm, and no bundles with a diameter exceeding 100 nm were found.

[0262] (Example 2)

[0263] The dispersion was prepared using the same method as in Example 1, and a doctor blade was used to coat the dispersion onto a silicon substrate. The doctor blade was spaced 50 μm from the silicon substrate. After drying, a film with a thickness of 40 nm was obtained. After removing the organic side-chain flavin with chloroform, the carbon nanotube sheet film was peeled off by immersing the silicon substrate in a water bath, and the film was retrieved using a frame, thus obtaining a protective film formed from the self-supporting film. The resulting protective film had an EUV transmittance of 85%. (SEM image...) Figure 15 The average diameter of the bundles was found to be 10.0 nm, and no bundles with a diameter exceeding 100 nm were found.

[0264] (Comparative Example 1)

[0265] 400 mg of carbon nanotubes (diameter ≥ 3 nm ≤ 5 nm, length ≥ 100 μm ≤ 600 μm, carbon content ≥ 99%) synthesized using the method described in International Publication No. 2006 / 011655 were added to 100 g of propylene glycol as an organic solvent. After stirring with a magnetic stirrer for 2 hours, the dispersion was ultrasonically dispersed using a probe-type homogenizer. The resulting carbon nanotube dispersion was degassed. The dispersion was then coated onto a silicon substrate using a scraper. The distance between the scraper and the silicon substrate was 240 μm. The dried thickness was 200 nm.

[0266] The obtained cross-sectional electron microscope image of the membrane ( Figure 16 It can be seen that the carbon nanotube sheets are not oriented in-plane. Based on the selected area electron diffraction pattern (...), Figure 17 At d = 0.21 nm, the loops of carbon-carbon bonds originating from the carbon nanotubes were observed to be connected even in the thickness direction, confirming that in-plane orientation was not performed in most areas.

[0267] R c-c R is 0.239.B The value is 0.353. This is from the FFT image of the cross-sectional electron microscope image (...). Figure 18 In the sample, no high-intensity striped pattern was observed along the axis of film thickness from the center, confirming that the orientation was not in-plane. FFT The value is 0.616.

[0268] From SEM images ( Figure 19 Bundles with diameters exceeding 100 nm were observed. When the aforementioned substrate was immersed in a water bath, the carbon nanotube sheets peeled off from the substrate broke into small fragments when retrieved into the frame, making it impossible to obtain a protective film formed by the self-supporting film.

[0269] (Comparative Example 2)

[0270] The dispersion was prepared using the same method as in Comparative Example 1 and then coated onto a silicon substrate using a scraper. The distance between the scraper and the silicon substrate was 100 μm. After drying, a film with a thickness of 90 nm was obtained.

[0271] The substrate was immersed in a water bath. The resulting carbon nanotube sheets peeled from the substrate broke into small fragments upon being retrieved into the frame, making it impossible to obtain a protective film as a self-supporting membrane. Bundles with diameters exceeding 100 nm were observed in SEM images.

[0272] The method for manufacturing the protective film according to a preferred embodiment of the present invention has been described above. However, these are merely illustrative examples, and the scope of the present invention is not limited thereto. In fact, those skilled in the art can make various modifications without departing from the spirit of the invention as claimed in the claims. Therefore, these modifications should also be understood to fall within the scope of the present invention.

[0273] Symbol Explanation

[0274] 10, 20 Protective film assembly; 100 Substrate; 102, 202 Protective film; 104 Mask; 106 Protective layer; 107 First frame; 108 Second frame; 109, 209 Support frame; 112 Adhesive sheet; 124 Bridge; 130 Hole; 180 Exposure device; 181 Exposure master; 182 Light source; 183 Illumination optical system; 184 Master; 185, 186 Filter window; 187 Sensing substrate; 188 Projection optical system; 189-191 Multilayer film mirror.

Claims

1. An exposure protective film, which is laid on the opening of a support frame. The thickness of the protective film is less than 200 nm. The protective film comprises carbon nanotube sheets. The carbon nanotube sheet comprises a bundle of multiple carbon nanotubes. The diameter of the bundle is less than 100 nm. The bundles are oriented in-plane within the carbon nanotube sheet. The protective film meets the following condition (1), (1) For the triangular lattice derived from the carbon nanotube bundles, d = 0.37 nm, i.e., g = 2.7 nm. -1 The nearby peaks, defined by the following formula, are the ratio R of the peak intensity along the thickness direction of the carbon nanotube sheet to the peak intensity along the in-plane direction of the carbon nanotube sheet. B Above 0.40 In the above formula, and This indicates that g = 2.7 nm -1 and g = 2.2nm -1 The diffraction intensity along the thickness direction of the carbon nanotube sheet at that location. and This indicates that g = 2.7 nm -1 and g = 2.2nm -1 The in-plane diffraction intensity of the carbon nanotube sheet at that location.

2. The protective film for exposure according to claim 1, wherein the diameter of the carbon nanotubes is 0.8 nm or more and 6 nm or less.

3. The protective film for exposure according to claim 1, wherein the carbon nanotube sheet has a mesh structure formed by the bundle in the planar direction.

4. The protective film for exposure according to claim 1, further comprising a protective layer in contact with the carbon nanotube sheet.

5. The protective film for exposure according to claim 4, wherein the protective layer comprises a component selected from SiO2. x Si a N b One or more of the following groups: SiON, Y₂O₃, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, B₄C, SiC, and Rh. SiO x In the case where x≤2, Si a N b The ratio of a / b is 0.7 to 1.

5.

6. A protective membrane assembly comprising: The protective film for exposure according to any one of claims 1 to 5, and A support frame that supports the protective film.

7. A protective film comprising carbon nanotube sheets, wherein the carbon nanotube sheets, Carbon nanotubes have a diameter between 0.8 nm and 6 nm. Carbon nanotubes have a length of 10 μm to 10 cm. The carbon content in carbon nanotubes is over 98% by mass. The protective film meets the following condition (1), (1) For the triangular lattice derived from the carbon nanotube bundles, d = 0.37 nm, i.e., g = 2.7 nm. -1 The nearby peaks, defined by the following formula, are the ratio R of the peak intensity along the thickness direction of the carbon nanotube sheet to the peak intensity along the in-plane direction of the carbon nanotube sheet. B Above 0.40 In the above formula, and This indicates that g = 2.7 nm -1 and g = 2.2nm -1 The diffraction intensity along the thickness direction of the carbon nanotube sheet at that location. and This indicates that g = 2.7 nm -1 and g = 2.2nm -1 The in-plane diffraction intensity of the carbon nanotube sheet at that location.

8. The protective film according to claim 7, wherein the length-to-diameter ratio of the carbon nanotubes, i.e., length / diameter, is 1 × 10⁻⁶. 4 Above 1×10 8 the following.

9. The protective film according to claim 7, further comprising a protective layer in contact with the carbon nanotube sheet.

10. The protective film according to claim 9, wherein the protective layer comprises a component selected from SiO2. x Si a N b One or more of the following groups: SiON, Y₂O₃, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, B₄C, SiC, and Rh. SiO x In the case where x≤2, Si a N b The ratio of a / b is 0.7 to 1.

5.

11. A protective membrane assembly, comprising: The protective film according to any one of claims 7 to 10, and A support frame that supports the protective film.

12. A protective film assembly frame, comprising: The protective film according to any one of claims 7 to 10, and The first frame that supports the protective film.

13. A protective membrane assembly comprising: The protective film assembly frame as described in claim 12, and A second frame connected to the protective film assembly frame.

14. An exposure original, comprising: Original version, and The protective film assembly as described in claim 11 or 13 is installed on the patterned side of the original.

15. An exposure apparatus having the exposure master as described in claim 14.

16. An exposure apparatus comprising: The light source that emits the exposure light The original exposure as described in claim 14, and An optical system that guides the exposure light emitted from the light source to the exposure master. The original image is configured such that exposure light emitted from the light source passes through the protective film and illuminates the original image.

17. The exposure apparatus according to claim 16, wherein the exposure light is EUV light.

18. A method for manufacturing a semiconductor device, comprising the following steps: The step of allowing exposure light emitted from the light source to pass through the protective film of the exposure master as described in claim 14 and irradiate the master, and reflecting the light off the master; and The step of exposing the sensing substrate into a pattern by allowing the exposure light reflected by the original to pass through the protective film and irradiate the sensing substrate.

19. The method for manufacturing a semiconductor device according to claim 18, wherein the exposure light is EUV light.

20. A method for manufacturing the protective film assembly of claim 6, comprising: Carbon nanotubes are fabricated using a chemical vapor deposition method, in the presence of a metal catalyst, at a temperature between 600°C and 1000°C, by adding water vapor at concentrations between 10 ppm and 10000 ppm. The obtained carbon nanotubes are formed into sheets to produce carbon nanotube sheets. The resulting carbon nanotube sheet is connected to a support frame with an opening in a manner that covers the opening surface.

21. The method for manufacturing the protective film assembly according to claim 20, wherein the film is sheet-like and is formed by preparing a carbon nanotube sheet from a dispersion of carbon nanotubes.

22. The method for manufacturing the protective film assembly according to claim 20, wherein the metal catalyst is disposed on a substrate.

23. A method for manufacturing the protective film assembly of claim 11, comprising: Carbon nanotubes are fabricated using a chemical vapor deposition method, in the presence of a metal catalyst, at a temperature between 600°C and 1000°C, by adding water vapor at concentrations between 10 ppm and 10000 ppm. The obtained carbon nanotubes are formed into sheets to produce carbon nanotube sheets. The resulting carbon nanotube sheet is connected to a support frame with an opening in a manner that covers the opening surface.

24. The method for manufacturing the protective film assembly according to claim 23, wherein the film is sheet-like and is formed by preparing a carbon nanotube sheet from a dispersion of carbon nanotubes.

25. The method for manufacturing the protective film assembly according to claim 23, wherein the metal catalyst is disposed on a substrate.

26. A method for manufacturing the protective film assembly of claim 6, comprising: A metal catalyst is patterned on a substrate. In the presence of the metal catalyst, water vapor at a temperature between 600°C and 10000°C is added at a concentration between 10 ppm and 10000 ppm. Multiple monolayer carbon nanotubes are then formed using a chemical vapor deposition method, thereby fabricating an integral carbon nanotube structure. The obtained monolithic carbon nanotube structure is formed into a film to manufacture carbon nanotube sheets. The resulting carbon nanotube sheet is connected to a support frame with an opening in a manner that covers the opening surface.

27. The method for manufacturing the protective film assembly according to claim 26, wherein the film is sheet-like and is formed by preparing a carbon nanotube sheet from a dispersion of carbon nanotubes.

28. A method for manufacturing the protective film assembly of claim 11, comprising: A metal catalyst is patterned on a substrate. In the presence of the metal catalyst, water vapor at a temperature between 600°C and 10000°C is added at a concentration between 10 ppm and 10000 ppm. Multiple monolayer carbon nanotubes are then formed using a chemical vapor deposition method, thereby fabricating an integral carbon nanotube structure. The obtained monolithic carbon nanotube structure is formed into a film to manufacture carbon nanotube sheets. The resulting carbon nanotube sheet is connected to a support frame with an opening in a manner that covers the opening surface.

29. The method for manufacturing the protective film assembly according to claim 28, wherein the film is sheet-like and is formed by preparing a carbon nanotube sheet from a dispersion of carbon nanotubes.

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