Dustproof film, dustproof film assembly frame, dustproof film assembly, manufacturing method thereof, exposure original, exposure apparatus, manufacturing method of semiconductor device

Abstract

This invention provides a dustproof film with higher EUV transmittance, a dustproof film assembly frame, and a dustproof film assembly. Furthermore, these provide a method for manufacturing an exposure master for EUV lithography and a semiconductor device that achieves high precision. A dustproof film for exposure is stretched at an opening of a support frame, wherein the thickness of the dustproof film is 200 nm or less, the dustproof film comprises a carbon nanotube sheet, the carbon nanotube sheet having a bundle formed of multiple carbon nanotubes, the bundle having a diameter of 100 nm or less, and the bundle being in-plane aligned within the carbon nanotube sheet.

Description

Technical Field

[0001] This invention relates to a photomask or reticle (hereinafter collectively referred to as "photomask") used in the manufacture of semiconductor devices using lithography technology, and a dustproof film assembly for a photomask dust cover to prevent dust adhesion. In particular, this invention relates to a dustproof film as an extreme ultraviolet (EUV) lithography film, a dustproof film assembly frame, a dustproof film assembly and its manufacturing method, and methods for manufacturing exposure plates and semiconductor devices using these materials. Prior Technology

[0002] Semiconductor devices are manufactured through a process called lithography. In lithography, an exposure device called a scanner or stepper is used to expose a mask with a circuit pattern, transferring the pattern onto a semiconductor wafer coated with photoresist. If dust or other foreign matter adheres to the mask, its shadow is transferred to the semiconductor wafer, preventing accurate transfer of the circuit pattern. As a result, sometimes the semiconductor device malfunctions and becomes a defective product.

[0003] In contrast, it is known to mount a dustproof film assembly, including a support frame with a dustproof film attached, onto a mask, causing foreign matter such as dust to adhere to the dustproof film and thus preventing it from adhering to the mask. The focus of the exposure light from the exposure apparatus is set on the mask surface and the semiconductor wafer surface, rather than on the surface of the dustproof film. Therefore, the shadow of foreign matter adhering to the dustproof film will not be imaged on the semiconductor wafer. Thus, compared to the case where foreign matter adheres to the mask, the degree to which it hinders the transfer of circuit patterns is significantly reduced, and the defect rate of semiconductor components is significantly suppressed, when foreign matter adheres to the dustproof film.

[0004] Dustproof films used in dustproof film assemblies are required to have the characteristic of transmitting exposure light with high transmittance. This is because if the transmittance of the dustproof film is low, the intensity of exposure light on the mask with the self-formed circuit pattern will be reduced, resulting in insufficient photoresist on the semiconductor wafer.

[0005] To date, the wavelength of lithography is gradually shortening, and EUV lithography, as the next generation of lithography technology, is being developed progressively. EUV light refers to light with wavelengths in the soft X-ray region or vacuum ultraviolet region, specifically around 13.5 nm ± 0.3 nm. For optical lithography, the resolution limit of the pattern is approximately half the exposure wavelength. Even using the immersion method, the resolution limit is still approximately one-quarter of the exposure wavelength. Furthermore, even using the immersion method with ArF lasers (wavelength: 193 nm), the predicted exposure wavelength limit is around 45 nm. Therefore, EUV lithography is anticipated as a revolutionary technology that can achieve significantly greater miniaturization compared to existing lithography methods.

[0006] Here, EUV light is easily absorbed by all substances. Furthermore, if exposure light such as EUV light shines on the dustproof film, a portion of its energy is absorbed by the dustproof film. Moreover, the energy of the EUV light absorbed by the dustproof film is converted into heat through various mitigation processes. Therefore, the temperature of the dustproof film rises during exposure. Additionally, in EUV dustproof film assemblies, it is necessary to have an extremely thin film, where the dustproof film attached to the assembly is a nanometer-sized film. Therefore, from the viewpoint of heat dissipation or heat resistance during the temperature rise, a dustproof film with higher EUV transmittance is required.

[0007] Patent document 1 discloses an invention concerning "optical elements for lithography devices", which specifically describes the use of carbon nanotube sheets, which may include "single-layer carbon nanotube sheets" or "multi-layer carbon nanotube sheets", and the advantage of nanotube sheets is that they have relatively low density.

[0008] Patent document 2 relates to dustproof films and dustproof film assemblies, and states that: if the density is increased in order to obtain film strength, high transmittance cannot be obtained; and the transmittance is poor due to the presence of many impurities such as metals in the manufacturing process of carbon nanotubes.

[0009] Patent document 3 discloses a carbon nanotube sheet, wherein the diameter of the carbon nanotube is 3 nm to 8 nm or 10 nm to 15 nm.

[0010] Patent document 4 discloses a carbon nanotube sheet, wherein the diameter of the cylinder is about 1 nm to 1000 nm, the length in the axial direction is about 0.1 μm to 1000 μm, and the L / D is about 100 to 10000. [Existing Technical Documents] [Patent Literature]

[0011] [Patent Document 1] Japanese Patent Publication No. 2011-530184 [Patent Document 2] International Publication No. 2014 / 142125 [Patent Document 3] Japanese Patent Application Publication No. 2001-48507 [Patent Document 4] Japanese Patent Application Publication No. 2006-69165 Summary of the Invention

[0012] [The problem that the invention aims to solve] Compared with the existing literature, the present invention provides a dustproof film with higher EUV transmittance and better heat resistance, a dustproof film assembly frame, and a dustproof film assembly. Furthermore, these provide a method for manufacturing an exposure master for EUV lithography that achieves high precision, and a method for manufacturing a semiconductor device. [Methods for solving problems]

[0013] To address the aforementioned issues, a dustproof film for exposure is provided, which is stretched at the opening of a support frame. The thickness of the dustproof film is less than 200 nm. The dustproof film includes a carbon nanotube sheet, which has a bundle formed by multiple carbon nanotubes, the diameter of which is less than 100 nm. The bundle is in-plane aligned within the carbon nanotube sheet.

[0014] By means of the above configuration, a dustproof film is provided that simultaneously satisfies the following conditions: the thickness of the dustproof film is less than 200 nm, the dustproof film includes a carbon nanotube sheet, the carbon nanotube sheet has a bundle formed by multiple carbon nanotubes, the diameter of the bundle is less than 100 nm, the bundle is in-plane aligned in the carbon nanotube sheet, but the dustproof film has high EUV transmittance, excellent durability relative to EUV, and film strength that can withstand atmospheric pressure to vacuum steps under EUV exposure system steps in the dustproof film assembly manufacturing process or EUV exposure system.

[0015] In one embodiment of the present invention, the diameter of the carbon nanotube can be 0.8 nm or more and 6 nm or less.

[0016] In one embodiment of the present invention, the carbon nanotube sheet may have a mesh structure formed by bundles in the surface direction.

[0017] In one embodiment of the present invention, a protective layer may be further included in contact with the carbon nanotube sheet.

[0018] In one embodiment of the present invention, the protective layer may comprise one or more of the group consisting of SiOx (x≦2), SiNb (a / b is 0.7~1.5), SiON, Y2O3, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, B4C, SiC and Rh.

[0019] In addition, to solve the aforementioned problem, a dustproof film is provided, which includes a carbon nanotube sheet, wherein the diameter of the carbon nanotube is 0.8 nm or more and 6 nm or less, the length of the carbon nanotube is 10 μm or more and 10 cm or less, and the carbon content in the carbon nanotube is 98% by mass or more.

[0020] By means of the above composition, a dustproof film is provided that simultaneously satisfies the following three conditions: the carbon content in the carbon nanotube is 98% by mass or more and is of high purity; the diameter of the carbon nanotube is 0.8 nm or more and 6 nm or less; and the length of the carbon nanotube is 10 μm or more and 10 cm or less. However, the dustproof film has high EUV transmittance, excellent durability relative to EUV, and film strength that can withstand atmospheric pressure to vacuum steps under EUV exposure system during the dustproof film assembly manufacturing process or the process.

[0021] In one embodiment of the present invention, the length-to-diameter ratio (length / diameter) of the carbon nanotube can be 1×10⁴ or more and 1×10⁸ or less.

[0022] If the diameter of the carbon nanotube is small, the strength of the dustproof film will increase, but the EUV transmittance will decrease. Therefore, in order to simultaneously satisfy EUV transmittance and film strength, the important factor is the ratio of the length of the nanotube to its diameter (length / diameter). If it is above 1×10⁴ and below 1×10⁸, then both EUV transmittance and film strength can be satisfied.

[0023] In one embodiment of the invention, the dustproof film may further include a protective layer in contact with the carbon nanotube sheet. The protective layer may be disposed on the exposure master side of the dustproof film, or it may be disposed on the dustproof film as the outermost surface.

[0024] In one embodiment of the present invention, the protective layer may comprise one or more of the group consisting of SiOx (x≦2), SiNb (a / b is 0.7~1.5), SiON, Y2O3, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, B4C, SiC and Rh.

[0025] By setting a protective layer, the dustproof film can be endowed with both resistance to hydrogen free radicals (i.e., resistance to reduction) and resistance to oxidation.

[0026] In one embodiment of the present invention, a dustproof film assembly is provided, which has the dustproof film and a support frame supporting the dustproof film.

[0027] In one embodiment of the present invention, a dustproof film assembly frame is provided, which has the dustproof film and a first frame supporting the dustproof film.

[0028] In one embodiment of the present invention, a dustproof film assembly is provided, which has the dustproof film assembly frame and a second frame connected to the dustproof film assembly frame.

[0029] In one embodiment of the present invention, an exposure master can be provided, which includes the master and a dustproof film assembly mounted on the patterned side of the master.

[0030] In one embodiment of the present invention, an exposure apparatus is provided having the exposure original.

[0031] In one embodiment of the present invention, an exposure apparatus is provided, comprising a light source emitting exposure light, an 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 dustproof film and irradiates the plate.

[0032] In one embodiment of the present invention, the exposure light may be EUV light.

[0033] In one embodiment of the present invention, a method for manufacturing a semiconductor device is provided, comprising: a step of transmitting exposure light emitted from a light source through a dustproof film of the exposure master to irradiate the master and being reflected by the master; and a step of transmitting exposure light reflected by the master through the dustproof film to irradiate a sensing substrate, thereby exposing the sensing substrate in a pattern.

[0034] In one embodiment of the present invention, the exposure light may be EUV light.

[0035] In one embodiment of the present invention, a method for manufacturing a dustproof film assembly is provided, comprising: manufacturing carbon nanotubes by chemical vapor deposition (CVD) in the presence of a metal catalyst, adding water vapor at a temperature of 600°C or higher and 1000°C or lower at a temperature of 10 ppm or higher and 10000 ppm or lower; forming the obtained carbon nanotubes into a sheet to manufacture a carbon nanotube sheet; and connecting the obtained carbon nanotube sheet to the support frame having an opening by covering the opening surface of the support frame.

[0036] The present invention provides a method for manufacturing a dustproof film assembly, comprising: manufacturing a carbon nanotube sheet from a dispersion of carbon nanotubes, and connecting the obtained carbon nanotube sheet to a support frame having an opening in such a way as to cover the opening surface of a support frame.

[0037] In one embodiment of the present invention, a method for manufacturing a dustproof thin film assembly is provided, wherein a metal catalyst is disposed on a substrate for chemical vapor deposition.

[0038] In one embodiment of the present invention, a method for manufacturing a dustproof thin-film assembly is provided, comprising: patterning a metal catalyst on a chemical vapor deposition substrate; 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 a plurality of monolayer carbon nanotubes by a CVD method to manufacture a carbon nanotube block structure; forming the obtained carbon nanotube block structure into a sheet to manufacture a carbon nanotube sheet; and connecting the obtained carbon nanotube sheet to a support frame having an opening by covering the opening surface of a support frame. The CVD method can form a plurality of monolayer carbon nanotubes that are erected in a direction perpendicular to the substrate surface.

[0039] In one embodiment of the present invention, a method for manufacturing a dustproof film assembly is provided, comprising: manufacturing a carbon nanotube sheet from a dispersion of carbon nanotubes, and connecting the obtained carbon nanotube sheet to a support frame having an opening in such a way as to cover the opening surface of a support frame. [The effects of the invention]

[0040] This invention provides a dustproof film with high EUV transmittance and excellent heat resistance, a dustproof film assembly frame, and a dustproof film assembly. Additionally, it provides a method for manufacturing an exposure master and a semiconductor device, wherein the exposure master uses these dustproof films, dustproof film assembly frames, and dustproof film assemblies, and thereby allows for the formation of patterns (e.g., linewidths of 32 nm or less) that can be miniaturized using EUV light, and enables pattern exposure with reduced resolution degradation caused by foreign matter. Simple Explanation of the Diagram

[0041] Figures 1(a) to (c) are schematic diagrams (cross-sectional views) illustrating the manufacturing process of a dustproof film, a dustproof film assembly frame, and a dustproof film assembly according to one embodiment of the present invention. Figures 2(a) to (c) are schematic diagrams (cross-sectional views) illustrating the manufacturing process of a dustproof film, a dustproof film assembly frame, and a dustproof film assembly according to an embodiment of the present invention. Figure 3 is a flowchart of a dustproof film, a dustproof film assembly frame, and a method for manufacturing a dustproof film assembly according to an embodiment of the present invention. Figure 4 is a selected area electron diffraction (SED) image of a cross-section of a carbon nanotube sheet according to an embodiment of the present invention. Figure 5 is a plot of the diffraction intensity in the thickness direction and the in-plane diffraction intensity of a carbon nanotube sheet according to an embodiment of the present invention, relative to the reciprocal lattice vector g. Figure 6 is a cross-sectional transmission electron microscope (TEM) image of a carbon nanotube sheet according to an embodiment of the present invention. Figure 7 is a Fast Fourier Transform (FFT) image of a cross-sectional electron microscope image of a carbon nanotube sheet according to an embodiment of the present invention. Figure 8 is a plot of the brightness in the thickness direction and the in-plane direction of the cross-sectional electron microscope image of a carbon nanotube sheet of an embodiment of the present invention, relative to the pixel distance from the center. Figures 9(a) to (c) are schematic diagrams (cross-sectional views) illustrating the manufacturing process of a dustproof film, a dustproof film assembly frame, and a dustproof film assembly according to one embodiment of the present invention. Figure 10 is a schematic cross-sectional view of an EUV exposure apparatus 180, which is an example of an exposure apparatus in this embodiment. Figures 11(a) to (d) are schematic diagrams (cross-sectional views) illustrating the manufacturing process of the dustproof film, dustproof film assembly frame, and dustproof film assembly of the modified examples of the present invention. Figure 12 is a schematic diagram (cross-sectional view) of a dustproof film assembly according to an embodiment of the present invention. Figure 13 is a selected area electron diffraction image of a cross-section of a carbon nanotube sheet according to an embodiment of the present invention. Figure 14 is a scanning electron microscope image of the carbon nanotube sheet according to an embodiment of the present invention. Figure 15 is a scanning electron microscope image of the carbon nanotube sheet according to an embodiment of the present invention. Figure 16 is a transmission electron microscope (TEM) image of a cross-section of the carbon nanotube sheet of the comparative example of the present invention. Figure 17 is a selected area electron diffraction image of a cross-section of a carbon nanotube sheet of a comparative example of the present invention. Figure 18 is a Fast Fourier Transform (FFT) image of a cross-section of a carbon nanotube sheet of the comparative example of the present invention, obtained by electron microscopy. Figure 19 is a scanning electron microscope image of the carbon nanotube sheet of the comparative example of the present invention. Implementation

[0042] Hereinafter, embodiments of the present invention will be described with reference to drawings and the like. It should be noted that the present invention can be implemented in a large number of 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 always examples and do not limit the interpretation of the present invention. Additionally, in this specification and the drawings, elements that are the same as those described with respect to previously shown figures are sometimes labeled with the same symbols, and detailed descriptions are appropriately omitted.

[0043] [definition] In this specification, when a component or region is positioned "above (or below)" other components or regions, unless otherwise specified, it includes not only the case where it is located directly above (or directly below) other components or regions, but also the case where it is located above (or below) other components or regions, that is, it also includes the case where other constituent elements are contained between the above (or below) other components or regions.

[0044] In this specification, EUV light refers to light with a wavelength of 5 nm or more and 30 nm or less. Preferably, the wavelength of EUV light is 5 nm or more and 14 nm or less.

[0045] In this specification, the term "dustproof film" refers to the film used in dustproof film assemblies. The dustproof film is preferably a self-supporting film. A self-supporting film is one that maintains its shape without a substrate or base material.

[0046] A dustproof membrane assembly refers to a device having a dustproof membrane and a support frame for supporting the dustproof membrane. A dustproof membrane assembly frame refers to a device with a first frame attached to the dustproof membrane. A dustproof membrane assembly also includes devices with a second frame attached to the dustproof membrane assembly frame. In this case, the first and second frames function as the support frame for supporting the dustproof membrane.

[0047] In this specification, trimming refers to cutting a substrate, or a substrate and the dustproof film formed thereon, to conform to the desired shape of the dustproof film assembly. Since dustproof film assemblies are often rectangular, examples of trimming cut into rectangular shapes are shown in this specification as specific examples of trimming.

[0048] In this specification, the step of removing a portion of the substrate by removing the residual dustproof film is referred to as back-side etching. The specification shows an example of back-side etching performed from the back side (the side of the substrate opposite to where the dustproof film is formed).

[0049] In this invention, the term "end" refers to a side, corner, or perimeter. Specifically, it includes the corner formed by the side of the substrate (or the first frame when the substrate is used as the first frame) or the support frame, the corner formed by the upper surface of the substrate (the side in contact with the dustproof film) and the side, and the area including the point where the upper surface of the substrate intersects with the two side surfaces, i.e., the perimeter.

[0050] In this invention, a bundle is a bundle formed by multiple carbon nanotubes.

[0051] In this invention, for the two-dimensional diffraction image of the cross-section of the carbon nanotube sheet, 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.

[0052] In this invention, the term "bundle aligned in the in-plane direction" means that the bundle of carbon nanotubes and the long axis direction of the carbon nanotubes are aligned in the same direction as the in-plane direction of the carbon nanotube sheet. In other words, it means that the length direction of the bundle is not upright in the thickness direction (Z-axis direction), but is located in the plane direction (XY direction). The length directions of the bundles do not need to be side by side in the X-axis or Y-axis direction, and a mesh-like structure can be formed.

[0053] In this invention, the term "bundle" refers to the alignment of the carbon nanotube bundles in the film thickness direction with the long axis of the carbon nanotubes oriented in the film thickness direction of the carbon nanotube sheet.

[0054] [Problems with the prior art discovered in this invention] The dustproof film for EUV dustproof film assemblies is typically manufactured by depositing SiN (silicon nitride) or similar materials onto a silicon wafer substrate. Furthermore, some dustproof films for EUV dustproof film assemblies utilize carbon nanotube sheets (Patent Document 1). However, Patent Document 2 states that increasing the density to achieve film strength results in lower transmittance, and the presence of numerous impurities such as metals in the carbon nanotubes during manufacturing further degrades transmittance.

[0055] Here, "low purity of carbon nanotube sheet" refers to a high impurity content, resulting in low EUV transmittance and easy absorption of EUV. Furthermore, if the dustproof film absorbs EUV, the energy of the EUV is converted into heat, causing the EUV-irradiated area to become hot and generate heat, thus reducing the durability of the dustproof film. In other words, it is known that with low purity of carbon nanotube sheet, the strength or EUV transmittance of the dustproof film deteriorates. The inventors have developed a dustproof film using carbon nanotube sheet with high EUV transmittance.

[0056] [Implementation Form 1] The manufacturing method of the dustproof film assembly 10 of the present invention will be described using Figures 1(a)-(c), 2(a)-(c), and 3. The dustproof film assembly 10 to be manufactured according to the present invention is a dustproof film assembly for EUV photolithography. First, a dustproof film 102 (Figure 1(b), Figure 3(s101)) is formed on a substrate 100 (Figure 1(a), for example, a silicon wafer). In the present invention, a carbon nanotube sheet described below is used as the dustproof film 102.

[0057] Carbon nanotubes (which can be bulk carbon nanotube structures) for a dustproof film 102 are formed on a chemical vapor deposition substrate using a CVD method (e.g., low-pressure chemical vapor deposition (LP-CVD) or plasma-enhanced chemical vapor deposition (PE-CVD)) in which a metal catalyst is present in the reaction system and an oxidant is added to the reaction environment. The oxidant can be water vapor, and its concentration can be 10 ppm or higher and 10,000 ppm or lower. Water vapor can also be added at temperatures above 600 degrees Celsius and below 1,000 degrees Celsius. Alternatively, a metal catalyst can be disposed on or patterned on the chemical vapor deposition substrate to synthesize the carbon nanotubes. Furthermore, the obtained carbon nanotubes can be single-layered or multi-layered, or they can be carbon nanotubes erected in a direction perpendicular to the surface of the chemical vapor deposition substrate. In detail, for example, it can be manufactured by referring to the super-growth method described in International Publication No. 2006 / 011655, etc.

[0058] Carbon nanotube sheets are manufactured using carbon nanotubes (which can be bulk carbon nanotube structures) obtained by peeling them off from a chemical vapor deposition substrate. The carbon nanotube sheets can be formed into films in the same manner as existing carbon nanotube sheets. Specifically, a dispersion is used, formed by dispersing the obtained carbon nanotubes or bulk carbon nanotube structures in a liquid.

[0059] A dispersant can be included in the dispersion. The inclusion of a dispersant results in finer bundles, facilitating in-plane alignment, which is preferable. Types of dispersants that can be used include organic side-chain flavins, flavin derivatives, sodium lauryl sulfate, sodium cholate, sodium deoxycholate, and sodium dodecylbenzenesulfonate.

[0060] The type of solvent used as a dispersion can be selected appropriately based on the solubility of the dispersant. For example, when using organoflavones 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.

[0061] When carbon nanotubes are dispersed into fine and uniform bundles in a dispersion solution using a super-growth method, it is ideal to use organoflavin as a dispersant.

[0062] The dispersion method can be appropriately selected. Ultrasonic dispersion, ball mill, roller mill, vibratory mill, mixer, jet mill, nano-processing machine, etc., can be used.

[0063] After the dispersion is coated onto the substrate 100, the liquid used in the dispersion is removed, thereby forming a carbon nanotube sheet on the substrate 100. If the dispersion in which the carbon nanotubes of the present invention are dispersed in a liquid is coated onto the substrate, 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) is obtained along with the evaporation of the liquid used in the dispersion to remove it. This forms a carbon nanotube sheet. The coating method is not particularly limited; examples include spin coating, dip coating, rod coating, spray coating, and electrospray coating.

[0064] The carbon nanotube sheet formed on the substrate 100 in the manner described above is used as the dustproof film 102. The metal catalyst used for the formation of the carbon nanotube can cause a decrease in EUV transmittance. It is preferable to obtain a dustproof film 102 that does not contain the metal catalyst used for the formation of the carbon nanotube by peeling the carbon nanotube off from the chemical vapor deposition substrate.

[0065] A mask 104 is deposited on the side opposite to the side where the dustproof film is formed (back side) (Fig. 1(b)), and then the mask in the exposed area is removed (Fig. 1(c)). Furthermore, the dustproof film 102 remaining in the exposed area is removed by etching, and a portion of the substrate is removed (Fig. 2(a), Fig. 3S103).

[0066] As part of the method for removing the substrate, back-side etching is used. As described, back-side etching is etching performed from the back side (the side of the substrate opposite to the side where the dustproof film is formed).

[0067] The substrate 100 does not have to be a silicon wafer substrate. The shape of the substrate is not limited to a perfect circle; it can also have an orientation flat or a notch. Furthermore, the dustproof film may not be formed on the entire substrate. As for the substrate 100 with the dustproof film formed, compared to aluminum alloys or similar materials used in ArF laser dustproof film assemblies, in order to reduce the thermal strain of the dustproof film assembly as a whole, it is preferable to use at least one of silicon, sapphire, or silicon carbide, which have a coefficient of linear thermal expansion similar to that of the dustproof film. Silicon is more preferred.

[0068] During back-side etching, with the aim of simultaneously forming a first frame 107 connected to the dustproof film 102, the silicon wafer outside the exposure area can also remain in a frame shape (Fig. 2(a)). In this case, the portion of the substrate that has not been removed is referred to as the first frame 107. By making the silicon wafer frame-shaped and utilizing it as a frame in this way, the step of separately bonding the dustproof film assembly on the first frame can be omitted, thereby manufacturing a dustproof film assembly frame.

[0069] The shape of the first frame is not particularly limited. From the viewpoint of improving strength, more substrate can remain as the first frame. Etching can also be performed with other frames attached to the portion that becomes the first frame before etching. By attaching other frames, the first frame can be strengthened. For example, a second frame 108 can be used as another frame. Furthermore, in subsequent steps, the second frame 108 can be connected in addition to the first frame 107 (Figure 2(b), Figure 3S105). The height of the EUV dustproof film assembly is limited, so it is preferable that the total height of the dustproof film and the support frame is 2.6 mm or less. A jig hole for fixing the dustproof film assembly to the exposure master or connecting it to the first frame can also be provided on the separately connected second frame 108.

[0070] 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 ionic leaching. Furthermore, to remove carbon-derived contaminants and allow hydrogen gas to flow within the exposure apparatus, it is preferable to use a material with resistance to hydrogen free radicals. The material of the second frame 108 is not particularly limited and can be any material commonly used in the frame of a dustproof 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. Among these, aluminum and aluminum alloys are preferred for their lightweight and rigidity. Additionally, the second frame 108 may have a protective layer on its surface.

[0071] In a dustproof film containing a carbon nanotube sheet with bundles, the protective layer may be the morphology of each bundle in the covered carbon nanotube sheet.

[0072] A dustproof film assembly (Figure 2(b)) is manufactured by connecting a dustproof film assembly frame (with a first frame attached to the dustproof film) to a second frame 108. The first frame 107 and the second frame 108 are support frames 109 that support the dustproof film, equivalent to frames with openings. Furthermore, the dustproof film assembly frame (with the first frame attached to the dustproof film) and the second frame 108 can be fixed by an adhesive or connected by pins. That is, pin holes can be provided at the corners or edges of the dustproof film assembly frame, and pin holes can also be provided at the overlapping portion of the second frame, connecting these frames using pins.

[0073] The dustproof film assembly 10 is attached to the exposure original 181 during photolithography (Figure 2(c), Figure 3S107).

[0074] The thickness of the dustproof film 102 is less than 200 nm. The dustproof film includes a carbon nanotube sheet. The carbon nanotube sheet has a bundle formed by multiple carbon nanotubes. The diameter of the bundle is less than 100 nm. The bundle is in-plane aligned in the carbon nanotube sheet.

[0075] Carbon nanotube sheets consist of bundles formed from multiple carbon nanotubes. The carbon nanotubes are brought together by van der Waals forces to form bundles. By forming bundles, a coarse fibrous structure can be created, thus increasing strength compared to individual carbon nanotubes.

[0076] In this embodiment, the diameter of the carbon nanotube bundle in the carbon nanotube sheet needs to be less than 100 nm. This is because if the bundle diameter exceeds 100 nm, the film thickness becomes thicker in the bundle overlap area, making it difficult to obtain a film with a thickness of less than 200 nm, thus failing to achieve high EUV transmittance. Moreover, the bundle diameter is preferably less than 20 nm. This is because the finer the bundle diameter, the thinner the film thickness in the bundle overlap area, thus obtaining a dustproof film with high EUV transmittance.

[0077] The diameter of the bundle can be determined by following the order below. 1) Use scanning electron microscope (SEM) images or atomic force microscope (AFM) images of a range (area) of 0.2 μm × 0.2 μm or more and 2 μm × 2 μm or less, taken at an observation magnification of 50,000 times or more and 300,000 times or less. 2) Draw the outline of the bundle. 3) Measure the vertical distance between two contour lines belonging to the same bundle. 4) The diameter of the bundle is not counted near the branches where the bundle branches and merges. 5) The image conditions used are as follows: the tangents of the two contour lines at the point where the diameter of the bundle is to be determined intersect at an angle of less than 15° or are parallel. 6) Draw a straight line from one side to the opposite side, and determine the diameter of the bundle by the outline of each bundle that is crossed by the line.

[0078] The bundles constituting the dustproof film are aligned in the in-plane direction of the film. Furthermore, in this invention, regarding the two-dimensional diffraction image of the cross-section of the carbon nanotube sheet, 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.

[0079] When the bundle of carbon nanotubes and the long axis of the carbon nanotubes are aligned with the in-plane direction of the carbon nanotube sheet, the bundles are aligned in the in-plane direction. Conversely, when the bundle of carbon nanotubes and the long axis of the carbon nanotubes are aligned with the film thickness direction of the carbon nanotube sheet, the bundles are aligned in the film thickness direction.

[0080] The alignment of the bundles can be investigated using electron microscopy images of cross sections of carbon nanotube sheets and selected area electron diffraction images.

[0081] When carbon nanotubes or bundles in a carbon nanotube sheet are aligned, they exhibit anisotropy in the diffraction image.

[0082] In cross-sectional electron microscopy images of carbon nanotube sheets in the range of 50 nm × 50 nm or larger, alignment in the in-plane direction is preferred. In electron beam diffraction, the lattice spacing d is represented by the reciprocal of the reciprocal lattice vector g. [Formula 1] d=1 / g

[0083] The reciprocal lattice vector g is given by 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, and is provided by the following formula. [Formula 2] g=r / λL

[0084] [Regarding the directionality of diffraction in carbon nanotubes] In the selected area electron diffraction (SED) image of the carbon nanotube sheet cross-section, a peak is observed at a position corresponding to d = 0.21 nm (g = 4.6 nm⁻¹), which is 3 / 2 times the C / C bond distance d originating from the unit lattice of the graphene sheet structure. Furthermore, this diffraction peak originates from the unit lattice of the graphene sheet and therefore appears along the bundle of carbon nanotubes and the long axis of the carbon nanotubes.

[0085] Furthermore, a peak in the triangular lattice originating from the carbon nanotube bundle is observed near d = 0.37 nm (g = 2.7 nm⁻¹). The intensity or scattering angle of this diffraction depends on the diameter or aggregation state of the nanotubes. In nanotube sheets using carbon nanotubes synthesized via the supergrowth method (SG method), a peak is observed near d = 0.37 nm, exhibiting a broad shape. Carbon nanotube sheets using carbon nanotubes synthesized via the eDIPS method have a different diameter and distribution than SG-method carbon nanotubes, therefore the position or shape of the peak differs.

[0086] The diffraction peak reflects the lattice originating from the bundle, i.e., the spacing of the carbon nanotubes that form the bundle, and therefore exhibits a diffraction peak in a direction perpendicular to the bundle and the long axis of the carbon nanotubes.

[0087] [The relationship between the orientation of carbon nanotube sheets and the anisotropy of diffraction peaks] When the carbon nanotube bundles and carbon nanotubes are completely in-plane aligned, the peak at d=0.21 nm (g=4.6 nm-1) of the unit cell derived from the graphene sheet structure is strongly exhibited in the in-plane direction. On the other hand, the peak near d=0.37 nm (g=2.7 nm-1) of the triangular lattice derived from the carbon nanotube bundles is strongly exhibited relative to the film thickness direction.

[0088] When the carbon nanotube bundles and the carbon nanotubes are randomly aligned in the in-plane and film thickness directions, any diffraction peak will exhibit the same peak intensity in both the in-plane and film thickness directions.

[0089] When the carbon nanotube bundles and the carbon nanotubes are completely perpendicularly aligned with the film surface, the peak value of the unit cell derived from the graphene sheet structure at d=0.21 nm (g=4.6 nm-1) is strongly exhibited in the film thickness direction. On the other hand, the peak value near d=0.37 nm (g=2.7 nm-1) of the triangular lattice derived from the carbon nanotube bundles is strongly exhibited in the in-plane direction.

[0090] [On the numericalization of orientation when intermediate orientation is present] The degree of alignment can be determined by comparing and analyzing the intensity profile in the in-plane direction with the intensity profile in the thickness direction of the two-dimensional electron diffraction image. Figure 4 shows an example of a selected area electron beam diffraction image of a cross-section of a carbon nanotube sheet.

[0091] Figure 5 shows plots of the diffraction intensity in the film thickness direction and the in-plane direction relative to the reciprocal lattice vector g, as shown in Figure 4. The vertical axis of Figure 5 represents brightness (relative brightness), and is a grayscale display of the diffraction intensity of the diffracted image in a 256-level range of 0 to 255. The diffraction intensity can be the detection intensity (in any unit) of the detector of an electron microscope, or, for example, the brightness (relative brightness) obtained by displaying the image based on the detection intensity distribution of the detector in a grayscale range of 0 to 255.

[0092] [Definition of the alignment properties of graphene sheet structure (g=4.6 nm⁻¹)] The diffraction peak at d=0.21 nm (g=4.6 nm-1) of the unit cell derived from the graphene sheet structure is defined by the following formula, Rc-c, which is the ratio of the peak intensity in the in-plane direction to the peak intensity in the film thickness direction. [Formula 3]

[0093] Here, and The diffraction intensities along the film thickness directions are g = 4.6 nm⁻¹ and g = 5.0 nm⁻¹. and This represents the in-plane diffraction intensity at g=4.6 nm⁻¹ and g=5.0 nm⁻¹.

[0094] The reason for taking the difference from the intensity at g=5.0 nm-1 is that the intensity that becomes the baseline is subtracted from the position that does not overlap with the peak at g=4.6 nm-1, thereby calculating only the magnitude of the diffraction intensity of the unit cell originating from the graphene sheet structure.

[0095] Furthermore, it is preferable to calculate Rc-c under the condition of unsaturated diffraction intensity at g=4.6 nm-1, based on the cumulative conditions during measurement or the comparison processing of images.

[0096] When the value of Rc-c is below 0.20, it means that in-plane alignment has been performed; when the value is above 0.20, it means that in-plane alignment has not been performed.

[0097] The value of Rc-c is preferably below 0.20, and even more preferably below 0.15.

[0098] In Figure 5, Rc-c is 0.129 and exhibits strong in-plane alignment, making it a preferred material for dustproof films.

[0099] [Definition of alignment of beam structure (g=2.7 nm⁻¹)] The peak near d=0.37 nm (g=2.7 nm-1) of the triangular lattice of the bundle originating from carbon nanotubes is defined by the following formula as the ratio RB of the peak intensity in the in-plane direction to the peak intensity in the film thickness direction. [Formula 4]

[0100] Here, and The diffraction intensity along the film thickness direction is g = 2.7 nm⁻¹ and g = 2.2 nm⁻¹. and This represents the in-plane diffraction intensity at g=2.7 nm⁻¹ and g=2.2 nm⁻¹. g=2.7 nm⁻¹ is the value of g that becomes the peak value of the diffraction intensity in Figure 5, and g=2.2 nm⁻¹ is the position used to subtract the intensity that becomes the baseline at the position that does not overlap with this diffraction peak.

[0101] Furthermore, it is preferable to calculate RB based on the cumulative conditions during measurement or the comparison processing of images, under the condition that the diffraction intensity is not saturated at g=2.7 nm-1 or g=2.2 nm-1, which serves as the baseline.

[0102] The value of g when calculating RB is not limited to 2.7 nm⁻¹ or 2.2 nm⁻¹, but can be appropriately selected. In particular, it is preferred to use the value of g when the peak position is at its maximum, and the value of g that can be obtained by subtracting the intensity of the baseline at the position that does not overlap with the diffraction peak.

[0103] In random alignment, the diffraction intensity in the in-plane direction is equal to that in the film thickness direction, but in… and The sign is reversed, therefore RB = -1. Increase and become When the in-plane orientation is strong, RB takes a positive value. The stronger the in-plane orientation, the larger the positive value of RB becomes.

[0104] If the value of RB is 0.40 or higher, it indicates that in-plane alignment has been performed; if it is less than 0.40, it indicates that in-plane alignment has not been performed. The value of RB is preferably 0.40 or higher, and more preferably 0.6 or higher. In Figure 5, RB is 1.02, and the bundle is strongly aligned in-plane, thus it is preferred as a dustproof film.

[0105] [Orientation analysis using Fast Fourier Transform (FFT) of cross-sectional electron microscope images] In addition, the degree of in-plane alignment of the dustproof film can be investigated using the Fast Fourier Transform (FFT) of the cross-sectional electron microscope image. When performing in-plane alignment, it is preferable to observe a strong striped pattern in the FFT image that runs from the center along the film thickness direction.

[0106] Figures 6 and 7 are TEM and FFT images of cross-sections of carbon nanotube sheets with in-plane alignment. It can be seen that a strong striped pattern with high intensity is observed along the thickness direction from the center.

[0107] Figure 8 is a plot of the brightness in the thickness direction and the in-plane direction of Figure 7, relative to the pixel distance from the center.

[0108] The vertical axis of Figure 8 represents brightness (relative brightness), and it is the result of displaying the FFT image in grayscale using a numerical range of 0 to 256 levels. There is no particular issue with the unit of brightness for the FFT image; for example, brightness (relative brightness) displayed in grayscale using a numerical range of 0 to 255 can be used.

[0109] The ratio of total brightness in the in-plane direction to total brightness in the film thickness direction is defined using the following formula: RFFT. [Formula 5]

[0110] Here, and This represents the brightness along the in-plane direction and the film thickness direction, representing the distance from the i-th pixel at the center. Additionally, and This refers to the brightness of the baseline at a location far from the center. In Figure 8, and It has a range of 450 to 500 pixels, and its brightness (relative brightness) is 45 when using a grayscale display with 256 levels of values ​​from 0 to 255.

[0111] If the RFFT value is below 0.60, it indicates that in-plane alignment has been performed; if the value exceeds 0.60, it indicates that in-plane alignment has not been performed. The RFFT value is preferably below 0.60. In Figure 8, the RFFT is 0.519, and the beam undergoes in-plane alignment, thus it is preferred as a dustproof film.

[0112] The carbon nanotube sheet with in-plane alignment of the bundles can be made with a film thickness equal to the diameter of the bundles, and high EUV transmittance can be achieved. Furthermore, the carbon nanotube sheet (or dustproof film) with in-plane alignment of the bundles can be made into a mesh structure in which the bundles are wound around each other in the in-plane direction, so that even a thickness of less than 100 nm can form a self-supporting film.

[0113] Carbon nanotube sheets (or dustproof films) have a mesh structure formed by bundles intertwined. This mesh structure can be observed using SEM or AFM images taken at magnifications of 50,000x to 300,000x, ranging from 0.2 μm × 0.2 μm to 2 μm × 2 μm. In SEM and AFM images, points where three or more bundles connect are considered bundle connection points. The mesh structure includes the straight portions of the bundles, the connection points, and the gaps that do not include these.

[0114] When stress is applied to the carbon nanotube sheet with a mesh structure that has been aligned in-plane, the stress can be dispersed, and the deformation or translational movement of the bundle can be suppressed. 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.

[0115] The dustproof film 102 comprises a carbon nanotube sheet, which has carbon nanotubes. During the synthesis of the carbon nanotubes, light elements other than carbon, such as metal catalysts or oxygen, are mixed in as impurities. Here, light elements refer to elements with atomic numbers less than 18 (argon).

[0116] The carbon nanotubes in the dustproof film 102 have a carbon content of 98% by mass or more. For example, carbon nanotubes synthesized using methods described in international publications such as International Publication No. 2006 / 011655 can be used as the dustproof film. The amount of metal contained in the carbon nanotubes can be determined by fluorescence X-ray diffraction. Alternatively, carbon nanotubes after removing the metal catalyst by acid cleaning can be used. The purity of the carbon nanotube sheet (the carbon content in the carbon nanotube sheet) is very high at 98% by mass or more, resulting in high EUV transmittance. Furthermore, due to the high EUV transmittance, the dustproof film assembly exhibits excellent durability relative to EUV. The amount of light elements such as oxygen contained in the carbon nanotubes can be determined by X-ray photoelectron spectrometry (XPS).

[0117] Furthermore, in this invention, the length of the carbon nanotubes in the dustproof film 102 is 10 μm or more and 10 cm or less, and the diameter is 0.8 nm or more and 6 nm or less. Alternatively, the center dimension of the diameter of the carbon nanotube is 1 nm or more and 4 nm or less, the length of the carbon nanotube is 10 μm or more and 10 cm or less, and the carbon content in the carbon nanotube is 98% by mass or more. In this specification, the center dimension of the diameter of the carbon nanotube is determined as follows. A transmission electron microscope (hereinafter referred to as TEM) is used to capture a transmission electron image on the film surface of the carbon nanotube sheet. The outer diameter, i.e., the diameter, of the carbon nanotube is measured based on the transmission electron image. A histogram is generated based on the data measured together, and the diameter at 90% of the measured diameter is calculated based on the histogram. Therefore, the so-called central diameter of carbon nanotubes being 1 nm or more and 4 nm or less means that 90% of the carbon nanotubes in the film have a diameter of 1 nm or more and 4 nm or less, while the diameter of the remaining 10% of carbon nanotubes does not need to be within the range of 1 nm or more and 4 nm or less.

[0118] In this invention, the carbon nanotubes are 10 μm or more and 10 cm or less in length, thus allowing them to intertwine and form a robust film (sheet). Furthermore, the diameter of the carbon nanotubes is 0.8 nm or more and 6 nm or less (or the center dimension of the carbon nanotube diameter is 1 nm or more and 4 nm or less), resulting in a low-density film with high EUV transmittance. Based on these characteristics, the film exhibits high EUV transmittance, high heat resistance due to high transmittance, and excellent durability relative to EUV, as well as high physical strength. Therefore, it possesses film strength capable of withstanding atmospheric pressure to vacuum steps in the manufacturing process of dustproof thin-film components or in EUV exposure systems.

[0119] Furthermore, in this invention, within the range of both the diameter and length of the carbon nanotube, the length-to-diameter ratio (length / diameter) of the carbon nanotube is preferably 1×10⁴ or more and 1×10⁸ or less. By falling within this range, EUV transmittance and film strength can be improved.

[0120] [Implementation Mode 2] Embodiment 2 is a form in which a chemical vapor deposition substrate used to form a carbon nanotube for dustproof film 102 by CVD is used as substrate 100.

[0121] The obtained carbon nanotube film consists of carbon nanotubes erected in a direction perpendicular to the substrate surface. Therefore, the erected carbon nanotubes can be physically tilted relative to another substrate, or the carbon nanotube film can be immersed in a liquid to physically tilt the erected carbon nanotubes, or a liquid can be poured into the carbon nanotube film to physically tilt the erected carbon nanotubes, or the generated carbon nanotube structure can be peeled off and sandwiched between two substrates to tilt the erected carbon nanotubes in a horizontal direction. In this invention, a carbon nanotube sheet with the carbon nanotubes (or carbon nanotube structures) substantially parallel to the substrate surface in the aforementioned manner is used as the dustproof film 102.

[0122] Except as described above, it is the same as Embodiment 1.

[0123] [Implementation Mode 3] Embodiment 3 is a configuration in which the dustproof film 202 is supported by the support frame 209 without using the first frame and the second frame. The manufacturing method of the dustproof film assembly 20 of the present invention will be described using FIG12.

[0124] Carbon nanotubes (which can be bulk carbon nanotube structures) are formed on a chemical vapor deposition substrate such as a silicon wafer, glass, metal, or polymer film. The obtained carbon nanotubes are then peeled off from the chemical vapor deposition substrate by floating them on the surface of a liquid such as water or an organic solvent. The film of the floating carbon nanotubes is then picked up using a support frame coated with an adhesive, thereby fixing it to the support frame. The resulting carbon nanotube film becomes a dustproof film 202.

[0125] As a method for obtaining a self-supported membrane by floating it on a liquid and then removing it, transfer techniques such as graphene can be used. For example, when removing a carbon nanotube membrane floating on the surface of a liquid, the membrane is supported by a substrate such as a polymer film, and fixed using a support frame coated with an adhesive, thereby allowing the membrane to be removed. The carbon nanotube sheet can be obtained by etching away the substrate such as the polymer film.

[0126] If the carbon nanotube block structure formed on the chemical vapor deposition substrate has sufficient strength as a film, the dustproof film 202 can be mechanically peeled off from the chemical vapor deposition substrate. The method of supporting the dustproof film 202 using the support frame 209 is not particularly limited, and the same method as existing dustproof film assemblies can be used.

[0127] The metal catalyst used in the formation of carbon nanotubes can cause a decrease in EUV transmittance. It is better to obtain a dustproof film 202 that does not contain the metal catalyst used in the formation of carbon nanotubes by peeling off the carbon nanotubes from the substrate used for chemical vapor deposition.

[0128] 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.

[0129] [Protective Layer] For applications requiring resistance to hydrogen free radicals (i.e., resistance to reduction) and oxidation, a protective layer can be provided in the EUV lithography dustproof film to protect the carbon nanotubes from the effects of hydrogen free radicals or oxidation. The protective layer 106 can be provided in connection with the carbon nanotube sheet. For example, it can be provided on the exposure substrate side of the dustproof films 102 and 202, or between the dustproof film 102 and the substrate 100 (Figure 9(a)), or it can be deposited on the dustproof films 102 and 202 as the top layer, or a combination thereof. Hydrogen free radicals can be generated on both sides of the dustproof film; therefore, it is preferable to combine these elements, i.e., to form the protective layer 106 on the exposure substrate side of the dustproof films 102 and 202, and then deposit it on the dustproof films 102 and 202 as the top layer.

[0130] Figures 9(a) to (c) show a dustproof film assembly with the protective layer 106 disposed on the exposure master side of the dustproof films 102 and 202 (Figure 9(b)), and a dustproof film assembly 10 with the exposure master 181 connected between the protective layer 106 disposed on the dustproof film 102 and the substrate 100 (Figure 9(c)). The protective layer 106 can be selected from SiOx (x≦2), SiNb (a / b is 0.7~1.5), SiON, Y2O3, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, B4C, SiC, and Rh.

[0131] To avoid hindering the transmission of EUV light, the ideal thickness of the protective layer is between 1 nm and 10 nm, and further ideally 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 the decrease in transmittance.

[0132] Ideally, the ratio of the protective layer's thickness to the dustproof film's thickness should be between 0.03 and 1.0. Within this range, the absorption of EUV light by the protective layer can be suppressed, thereby preventing a decrease in transmittance.

[0133] Furthermore, if a protective layer is laminated, 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 dustproof film—resulting in reduced transmittance. The EUV light reflectance at these layer interfaces can be calculated based on the thickness of the dustproof film and the protective layer, as well as the types of elements constituting them. Moreover, similar to the principle of antireflective coatings, optimizing the film thickness can reduce reflectance.

[0134] The ideal thickness of the protective layer is set within a range that suppresses the reduction in EUV light transmittance caused by absorption and reflection, while also providing protection against oxidation and reduction. There are no particular limitations on the thickness uniformity or surface roughness of the protective layer. During the patterning step of EUV exposure, the protective layer can be either a continuous layer or an island-like structure, as long as it does not produce film thickness inhomogeneity, transmittance inhomogeneity due to surface roughness, or obstacles caused by EUV light scattering. Furthermore, even with film thickness inhomogeneity, surface roughness may still exist.

[0135] Ideally, the average refractive index of the dustproof film, after combining the dustproof film and the protective layer, should be between 1.1 and 3.0. The refractive index can be measured using methods such as spectroscopic elliptic polarization. Furthermore, the ideal average density of the dustproof film, after combining the dustproof film and the protective layer, should be between 0.1 g / cm³ and 2.2 g / cm³. The density can be measured using methods such as X-ray reflectance analysis.

[0136] The thickness of the dustproof film (total thickness when there are two or more layers) can be, for example, 10 nm or more and 200 nm or less, preferably 10 nm or more and 100 nm or less, more preferably 10 nm or more and 70 nm or less, even more preferably 10 nm or more and 50 nm or less, and even more preferably 10 nm or more and 30 nm or less. The thinner the film, the higher the EUV transmittance of the dustproof film can be obtained.

[0137] The thickness of the dustproof film can be determined using the following method: The dustproof film is transferred onto a substrate, and AFM (Anti-Factor Measuring) is performed over an area of ​​100 μm² to 1000 μm². The measurement area includes both the substrate surface and the film. The average height of the substrate and the film is measured separately over an area of ​​10 μm² or more, and the film thickness is determined based on the difference between the average thicknesses of the substrate and the film.

[0138] The dustproof film preferably has high EUV light transmittance, and the transmittance of the light used for EUV lithography (e.g., light with a wavelength of 13.5 nm or light with a wavelength of 6.75 nm) is preferably 50% or more, more preferably 80% or more, and even more preferably 90% or more. When the dustproof film and protective layer are laminated, the transmittance of the film comprising these layers is preferably 50% or more.

[0139] (Evaluation of the EUV resistance of the dustproof film) EUV resistance can be evaluated by irradiating the dustproof film with EUV light and performing various analyses on the irradiated and unirradiated areas. For example, compositional analysis methods such as XPS, energy-dispersive spectrometer (EDS), and Rutherford backscattering spectrometry (RBS) can be used; structural analysis methods such as XPS, electron energy loss spectroscopy (EELS), IR, or Raman spectroscopy can be used; film thickness evaluation methods such as elliptic polarization, interferometric spectroscopy, and X-ray reflectance analysis can be used; and appearance or surface shape evaluation methods such as microscopic observation, SEM, or AFM can be used. Heat dissipation can be studied in more detail using the analytical results from combined computer simulations.

[0140] Dustproof films are not limited to EUV light. Depending on the evaluation criteria, appropriate methods such as vacuum ultraviolet irradiation, ultraviolet-visible light irradiation, infrared irradiation, electron beam irradiation, plasma irradiation, and heat treatment can be selected to evaluate the durability of dustproof films.

[0141] When a protective layer is provided, the evaluation can be performed using the dustproof film that combines the dustproof film and the protective layer.

[0142] [Evaluation of the strength of the dustproof film] Methods for evaluating the strength of dustproof films include those using a nano indenter. Other methods for evaluating film strength include resonance testing, bulge testing, evaluation of the presence or absence of film damage caused by airflow, evaluation of the presence or absence of film damage caused by vibration testing, and tensile strength testing of dustproof films using a tensile testing apparatus.

[0143] When a protective layer is provided, the evaluation can be performed using the dustproof film that combines the dustproof film and the protective layer.

[0144] [Film adhesive layer] The film adhesive layer is used to bond the support frame 209 and the dustproof film 202 when they are manufactured separately. The film adhesive layer may be, for example, a layer containing acrylic resin adhesive, epoxy resin adhesive, polyimide resin adhesive, silicone resin adhesive, inorganic adhesive, etc. From the viewpoint of maintaining the vacuum level during EUV exposure, the film adhesive layer is preferably a film adhesive layer with low gas escape. As a method for evaluating gas escape, a temperature-induced desorption gas analyzer can be used, for example.

[0145] In addition, there are no particular restrictions on the method of fixing the dustproof film to the support frame. The dustproof film can be directly attached to the support frame, or it can be fixed to the support frame by the film adhesive layer located on one end face of the support frame, or by mechanical fixing or the attraction of magnets, etc.

[0146] As an evaluation method for the adhesion between the dustproof film and the support frame, for example, the presence or absence of film damage or peeling can be evaluated by changing the pressure, area, distance, and angle and by blowing air, or by changing the acceleration and amplitude and by vibration testing.

[0147] [Original version uses adhesive layer] The original adhesive layer is the layer that bonds the dustproof film assembly to the original substrate. The original adhesive layer can be located at the end of the dustproof film assembly on the side where the dustproof film is not stretched. Examples of original adhesive layers include double-sided tape, silicone adhesives, acrylic adhesives, polyolefin adhesives, and inorganic adhesives. From the viewpoint of maintaining the vacuum level during EUV exposure, the original adhesive layer is preferably one with low escaping gas. As a method for evaluating escaping gas, a temperature-induced desorption gas analyzer can be used, for example.

[0148] Since the film adhesive layer and the original adhesive layer are exposed to scattered EUV light within the EUV exposure apparatus, they ideally need to be EUV resistant. Low EUV resistance will reduce the adhesion or strength of the adhesive during EUV exposure, leading to defects such as adhesive peeling or foreign matter formation within the exposure apparatus. EUV resistance evaluation can be performed using methods such as composition analysis (XPS, EDS, RBS, etc.), structural analysis (XPS, EELS, IR, or Raman spectroscopy), film thickness evaluation (elliptic polarization, interferometric spectroscopy, X-ray reflectance), appearance or surface shape evaluation (microscopic observation, SEM, or AFM), and strength and adhesion evaluation using nanoindentation or peel tests.

[0149] For lithography, accurate transfer of circuit patterns is required. Therefore, the transmittance of exposed light needs to be substantially uniform within the exposure range. By using the dustproof film of this embodiment, a dustproof film assembly with a fixed transmittance within the exposure range can be obtained.

[0150] Applications of dustproof film assemblies The dustproof film assembly of the present invention serves not only as a protective component to prevent foreign matter from adhering to the original plate within an EUV exposure apparatus, but also as a protective component to protect the original plate during storage or transport. For example, if the dustproof film assembly is installed on the original plate (exposing the original plate), it can be stored directly after being removed from the EUV exposure apparatus. Methods for installing the dustproof film assembly on the original plate include methods using adhesives, electrostatic adsorption, and mechanical fixing.

[0151] [Original version exposed] The original exposure plate of this embodiment includes the original plate and the dustproof film assembly of this embodiment installed on the original plate.

[0152] The original exposure of this embodiment has the dustproof film assembly of this embodiment, and therefore performs the same effect as the dustproof film assembly of this embodiment.

[0153] There are no particular limitations on the method of installing the original plate onto the dustproof film assembly of this embodiment. For example, the original plate can be directly attached to the support frame, or it can be fixed to the support frame by an adhesive layer on the original plate located on one end face of the support frame, or by mechanical fixing or the attraction of magnets, etc.

[0154] Here, as a prototype, a prototype comprising a support substrate, a reflective layer deposited on the support substrate, and an absorber layer formed on the reflective layer can be used. The absorber layer absorbs a portion of the EUV light, forming the desired image 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.

[0155] [Exposure device] The exposure apparatus of this embodiment possesses the exposure master of this embodiment. Therefore, it achieves the same effect as the exposure master of this embodiment.

[0156] The exposure apparatus of this embodiment preferably comprises: a light source that emits exposure light (preferably EUV light, more preferably EUV light; the same applies hereinafter), an exposure original of this embodiment, and an optical system that guides the exposure light emitted from the light source to the exposure original, and the exposure original is configured such that the exposure light emitted from the light source passes through a dustproof film and illuminates the original.

[0157] According to this approach, in addition to forming patterns that can be miniaturized using EUV light (e.g., with a linewidth of 32 nm or less), even when using EUV light where resolution issues caused by foreign objects are a problem, pattern exposure with reduced resolution issues caused by foreign objects can be performed.

[0158] [Semiconductor Device Manufacturing Method] The method for manufacturing a semiconductor device according to this embodiment includes: a step of transmitting exposure light emitted from a light source through the dustproof film of the exposure master of this embodiment to irradiate the master and being reflected by the master; and a step of transmitting exposure light reflected by the master through the dustproof film to irradiate a sensing substrate, thereby exposing the sensing substrate in a pattern.

[0159] According to the semiconductor device manufacturing method of this embodiment, even when using EUV light where resolution defects caused by foreign objects are prone to become a problem, a semiconductor device with reduced resolution defects caused by foreign objects can be manufactured.

[0160] Figure 10 is a schematic cross-sectional view of an EUV exposure apparatus 180, which is an example of an exposure apparatus in this embodiment.

[0161] As shown in FIG10, 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.

[0162] The exposure original 181 includes a dustproof film assembly 10 comprising a dustproof film 102 and a support frame, and an original 184. The exposure original 181 is configured such that EUV light emitted from the light source 182 passes through the dustproof film 102 and irradiates the original 184.

[0163] The original 184 reflects the EUV light in a patterned manner.

[0164] Dustproof film 102 and dustproof film assembly 10 are examples of dustproof film and dustproof film assembly of this embodiment.

[0165] 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 plate 184.

[0166] In addition, the EUV exposure apparatus 180 includes a projection optics system 188 that guides the EUV light reflected by the original 184 toward the sensing substrate 187.

[0167] 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, thereby exposing the sensing substrate 187 in a patterned manner. Furthermore, the EUV exposure is performed under reduced pressure conditions.

[0168] EUV light source 182 emits EUV light toward illumination optical system 183.

[0169] The EUV light source 182 includes a target material and a pulsed laser irradiation unit. EUV is obtained by irradiating the target material with a pulsed laser to generate plasma. If the target material is Xe, EUV with wavelengths of 13 nm to 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 target within the range of 5 nm to 30 nm is acceptable.

[0170] The illumination optical system 183 focuses the light irradiated by the EUV light source 182 and homogenizes the illuminance to illuminate the original 184.

[0171] The illumination optical system 183 includes a multilayer mirror 189 for adjusting the optical path of EUV, and an optical coupler (optical integrator). The multilayer mirror is a multilayer film formed by alternating layers of molybdenum (Mo) and silicon (Si).

[0172] There are no particular restrictions on the installation method of filter windows 185 and 186. Examples include attaching them with adhesives or mechanically fixing them into the EUV exposure device.

[0173] A filter window 185 disposed between the light source 182 and the illumination optical system 183 captures stray particles (debris) generated by the light source, so that the stray particles (debris) do not adhere to the components (e.g., multilayer lens 189) inside the illumination optical system 183.

[0174] On the other hand, the filter window 186, which is located between the illumination optical system 183 and the original 184, captures particles (debris) scattered from the light source 182 side, so that the scattered particles (debris) do not adhere to the original 184.

[0175] Furthermore, foreign matter adhering to the original wafer absorbs or scatters EUV light, thus causing poor resolution of the wafer. Therefore, the dustproof film assembly 10 is installed to cover the EUV light irradiation area of ​​the original wafer 184. EUV light passes through the dustproof film 102 and irradiates the original wafer 184.

[0176] EUV light reflected by the original plate 184 passes through the dustproof film 102 and is irradiated onto the sensing substrate 187 through the projection optical system 188.

[0177] The projection optical system 188 focuses the light reflected from the original plate 184 onto the sensing substrate 187. The projection optical system 188 includes multiple multilayer film lenses 190, 191, etc., for adjusting the optical path of EUV.

[0178] The sensing substrate 187 is a substrate such as a semiconductor wafer coated with a photoresist. The photoresist is cured in a patterned manner by EUV reflected by the original substrate 184. The photoresist is developed and the semiconductor wafer is etched, thereby forming the desired pattern on the semiconductor wafer.

[0179] Furthermore, the dustproof film assembly 10 is mounted on the original wafer 184 via an adhesive layer or the like. Foreign matter adhering to the original wafer absorbs or scatters EUV, thus causing poor resolution of the wafer. Therefore, the dustproof film assembly 10 is mounted in such a way that it covers the EUV irradiation area of ​​the original wafer 184, and EUV irradiates the original wafer 184 through the dustproof film 102.

[0180] As for the method of installing the dustproof film assembly 10 onto the original plate 184, any method that prevents foreign matter from adhering to the surface of the original plate is acceptable. Examples include methods such as attaching the dustproof film assembly 10 to the original plate 184 using an adhesive, electrostatic adsorption, or mechanical fixing. There are no particular limitations. The method of attaching using an adhesive is preferred.

[0181] [Variation Example 1] This invention may also include a particle removal step. Examples of particle removal methods include wet cleaning, mechanical cleaning, and dry cleaning, but are not limited to these. Examples of wet cleaning methods include RCA cleaning using SC1 or SC2 cleaning. SC1 cleaning utilizes ammonia and hydrogen peroxide for particle removal, while SC2 cleaning utilizes hydrochloric acid and hydrogen peroxide for heavy metal removal. In addition, cleaning using pure water or organic solvents can be performed. Furthermore, cleaning using sulfuric acid and hydrogen peroxide (a mixture of sulfuric acid and hydrogen peroxide), buffered fluoride (a mixture of hydrofluoric acid and ammonium fluoride), or hydrofluoric acid can be used. Cleaning methods can also be combined in any order. Dry cleaning methods include ashing cleaning using O2 plasma and argon sputtering.

[0182] [Variation Example 2] In this invention, chamfering can also be performed on at least one portion of the substrate, support frame, first frame, and second frame. In this specification, chamfering includes both R-surface and C-surface processing. R-surface processing refers to forming a curved portion by processing at least one end (side, corner, or other angle) of the substrate, support frame, first frame (including those formed by back-side etching of the substrate), or second frame. C-surface processing, in this specification, refers to cutting at least one end at an angle (more than 100 degrees and less than 170 degrees). By performing this processing, sharp portions (acute angles) are removed, and even if collisions occur with certain components during post-manufacturing transport or processing, it is difficult to generate fragments.

[0183] [Variation Example 3] In this invention, one or more holes may be formed on the substrate 100 (Figs. 11(a) to (d)). Figs. 11(a) to (c) show diagrams of holes 130 formed in four directions on the substrate. Fig. 11(a) is a top view, and Figs. 11(b) and (c) are cross-sectional views along line A' of Fig. 11(a) as a top view. As shown in Fig. 11(b), one or more holes 130 may be formed on the dustproof film 102 on the formed substrate 100. The holes may not penetrate the substrate, as shown in Fig. 11(b). Of course, they may also penetrate the substrate, as shown in Fig. 11(c). As shown in Figs. 11(b) and (c), holes may also be formed on the dustproof film and the substrate. When a through-hole is provided in the substrate, and when the trimming step is performed by etching or when back-side etching is performed, steps such as temporarily blocking the hole during etching to protect it, or using a photoresist to protect the hole portion, can be implemented. 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 provided. Preferably, a hole with a diameter of approximately 200 μm to 700 μm can be provided. Furthermore, the shape of the hole 130 is not particularly limited, and it can also be polygonal (e.g., approximately quadrilateral). In the case of an approximately quadrilateral shape, the length of each side is not limited. A hole with a long side length of 100 μm to 3000 μm and a short side length of 50 μm to 1000 μm can be provided. Preferably, the long side length is 150 μm to 2000 μm and the short side length is 100 μm to 700 μm. The hole 130 can also be disposed on the side of the dustproof film assembly as shown in Figure 11(a), but there is no limitation on the location of the hole. The hole 130 can be used as a clamping hole or vent for mounting or removing the dustproof film to the photomask, but the hole is not an essential component of the dustproof film assembly.

[0184] Hole 130 is formed by ultra-short pulse laser, other lasers, etching, etc. In the case of laser formation, from the viewpoint of producing a high-quality dustproof film with minimal dust, it is preferable to use an ultra-short pulse laser (e.g., a picosecond laser or a nanosecond laser) to form the hole, which reduces debris during processing. However, instead of forming the hole at the stated time point, the process can be simplified by simultaneously forming the hole 130 during etching on the back side of the substrate (described later). That is, the sequence is as follows: after trimming, hole formation and etching are performed simultaneously. When using a nanosecond laser, the conditions can be set to a repetitive oscillation frequency of 5 kHz or higher and 15 kHz or lower, a pulse energy of 5 W or higher and 15 W or lower, a scan rate of 5 mm or higher and 30 mm per second, and a scan count of 40 or higher and 300 or lower, but are not limited to these conditions. Additionally, when processing using an extremely short pulse laser, a laser slag inhibitor can also be used. Examples of slag inhibitors include, for instance, a chemical reagent such as CBX, which is a mixture of microcrystalline graphite and isopropyl alcohol (IPA), applied to the substrate before hole formation, but this is not a limitation. When using a slag inhibitor, it is removed by cleaning after hole formation. Other methods for preventing slag adhesion include, for example, performing laser processing while simultaneously spraying helium gas onto the substrate to suppress slag adhesion.

[0185] [Variation Example 4] Additionally, as shown in Figure 11(d), as a trimming method that generates less dust, a bridge portion 124 can be formed inside the substrate where the adhesive sheet is attached after attaching the elastic adhesive sheet 112, which has elasticity and whose adhesion decreases when subjected to external stimuli, to both sides of the substrate. Then, the trimming is performed by cutting into the bridge portion 124. Furthermore, in this invention, only the substrate can be trimmed, or the dustproof film formed on the substrate can be trimmed together with the substrate.

[0186] As an example of trimming, consider trimming into a rectangular shape, but there are no limitations on the trimming shape; it can be processed into any shape. Furthermore, there are no limitations on the trimming method. For example, there are methods that mechanically apply force to cut the dustproof film and substrate, as well as laser cutting, laser half-cutting (stealth cutting), blade dicing, sandblasting, anisotropic etching, or dry etching. However, methods that generate less dust from foreign particles during trimming are preferred. Moreover, since the dustproof film is extremely thin after back-side etching, cleaning is impossible. However, if dust-generating steps such as trimming are performed before back-side etching, cleaning can be performed before back-side etching, thereby producing a dustproof film, dustproof film assembly frame, and dustproof film assembly with less dust. [Example]

[0187] (Example 1) 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 organic side-chain flavin as a dispersant, were added to 100 mL of toluene. After stirring with a magnetic stirrer at approximately 480 rpm for 2 hours, the suspension was ultrasonically dispersed for a total of 2 hours using a probe homogenizer at 40% output. During this period, the suspension was cooled in an ice bath for 5 minutes every 20 minutes. The obtained carbon nanotube dispersion was then degassed.

[0188] The dispersion was coated onto a silicon substrate using a blade. The gap between the blade 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 flavins with chloroform, the silicon substrate was immersed in a water bath to peel off the film from the carbon nanotube sheet. The film was then collected using a frame to obtain a dustproof film serving as a self-supporting membrane.

[0189] The cross-sectional electron microscope image of the obtained dustproof film (Fig. 6) shows that the beam is aligned in-plane throughout the entire area of ​​the film. The selected area electron diffraction image (Fig. 13) shows that the two carbon-carbon rings originating from the carbon nanotubes at d=0.21 nm and 0.12 nm are weak in intensity and cut off in the film thickness direction. At d=0.37 nm, a wide spot of triangular lattice structure originating from the beam appears side-by-side in the film thickness direction. Anisotropy of scattering intensity is observed in both the film thickness direction and the in-plane direction.

[0190] Figure 5 shows the diffraction intensity in the thickness direction and the in-plane direction relative to the reciprocal lattice vector g. From Figure 5, Rc-c is calculated to be 0.129 and RB to be 1.02. This indicates that the bundle formed by the carbon nanotubes undergoes strong alignment.

[0191] In the FFT image of the cross-sectional electron microscope image (Fig. 7), a strong striped pattern with high intensity along the axis from the center along the film thickness direction was observed, and the alignment in the in-plane direction was confirmed.

[0192] Figure 8 shows the brightness in the film thickness direction and the in-plane direction of the FFT image relative to the pixel distance from the center. The RFFT is 0.519, and in-plane alignment of the beams is confirmed. The average beam diameter calculated from the SEM image (Figure 14) is 9.0 nm, and no beams with a diameter exceeding 100 nm were observed.

[0193] (Example 2) A dispersion prepared using the same method as in Example 1 was applied to a silicon substrate by a blade. The gap between the blade and the silicon substrate was 50 μm. After drying, a film with a thickness of 40 nm was obtained. After removing the organic side-chain flavins with chloroform, the silicon substrate was immersed in a water bath to peel off the film from the carbon nanotube sheet. The film was then collected using a frame to obtain a dustproof film containing a self-supporting membrane. The obtained dustproof film had an EUV transmittance of 85%. The average diameter of the beams determined from the SEM image (Figure 15) was 10.0 nm, and no beams with a diameter exceeding 100 nm were observed.

[0194] (Comparative Example 1) 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 the organic solvent. After stirring with a magnetic stirrer for 2 hours, the mixture was ultrasonically dispersed using a probe homogenizer. The obtained carbon nanotube dispersion was degassed. The dispersion was then coated onto a silicon substrate. The gap between the blade and the silicon substrate was 240 μm. The thickness after drying was 200 nm.

[0195] According to the cross-sectional electron microscope image of the obtained film (Fig. 16), the bundle of carbon nanotubes was not in-plane aligned. Selected area electron diffraction (Fig. 17) confirmed that the carbon-carbon bond rings originating from the carbon nanotubes, seen at d=0.21 nm, were also connected in the film thickness direction, and were not in-plane aligned in most areas.

[0196] Rc-c is 0.239, and RB is 0.353. In the FFT image of the cross-sectional electron microscope image (Fig. 18), no strong striped pattern was observed along the axis from the center along the film thickness direction, and it was confirmed that the alignment did not occur in the in-plane direction. The RFFT value is 0.616.

[0197] SEM images (Figure 19) showed bundles with diameters exceeding 100 nm. When the substrate was immersed in a water bath, the film of the carbon nanotube sheet peeled off from the substrate was slightly broken when it was framed, making it impossible to obtain a dustproof film containing a self-supporting membrane.

[0198] (Comparative Example 2) A dispersion prepared using the same method as in Comparative Example 1 was applied to a silicon substrate by a blade. The gap between the blade and the silicon substrate was 100 μm. After drying, a film with a thickness of 90 nm was obtained.

[0199] When the substrate was immersed in a water bath, the carbon nanotube sheet peeled off from the substrate experienced minor breakage when it was framed, making it impossible to obtain a dustproof film as a self-supporting membrane. Bundles with diameters exceeding 100 nm were observed based on SEM images.

[0200] The method for manufacturing a dustproof film according to a preferred embodiment of the present invention has been described above. However, these are merely simple examples, and the technical scope of the present invention is not limited to these embodiments. In fact, those skilled in the art will be able to make various modifications without departing from the spirit of the present invention as claimed in the patent application. Therefore, it should be understood that such modifications also fall within the technical scope of the present invention.

[0201] 10, 20: Dustproof membrane assembly 100:Substrate 102, 202: Dustproof film 104: Mask 106: Protective layer 107: First frame 108: Second frame 109, 209: Support frame 112: Adhesive sheet 124: Bridging section 130: Kong 180: Exposure device 181: Original Version Exposed 182: Light Source 183: Illumination Optical System 184: Original Version 185, 186: Filter windows 187: Sensor substrate 188: Projection Optical System 189~191: Multi-coated lenses S101, S103, S105, S107: Steps

Claims

1. A dustproof film for exposure, stretched in an opening of a support frame, wherein the thickness of the dustproof film is less than 200 nm, the dustproof film comprises a carbon nanotube sheet, the carbon nanotube sheet having a bundle formed of a plurality of carbon nanotubes, the diameter of the bundle being less than 100 nm, and the bundle being in-plane aligned in the carbon nanotube sheet.

2. The dustproof film for exposure as claimed in claim 1, wherein the dustproof film is a self-supporting film.

3. The dustproof film for exposure as claimed in claim 1 or 2, wherein the diameter of the carbon nanotube is 0.8 nm or more and 6 nm or less.

4. The dustproof film for exposure as claimed in claim 1 or 2, wherein the carbon nanotube sheet has a mesh structure formed by the bundle in the planar direction.

5. The dustproof film for exposure as claimed in claim 1 or 2, further comprising a protective layer in contact with the carbon nanotube sheet.

6. The dustproof film for exposure as claimed in claim 5, wherein the protective layer comprises one or more selected from the group consisting of SiOx (x≦2), SiNb (a / b is 0.7 to 1.5), SiON, Y2O3, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, B4C, SiC and Rh.

7. A dustproof film assembly comprising: an exposure dustproof film as described in any one of claims 1 to 6; and a support frame supporting the dustproof film.

8. A dustproof film comprising a carbon nanotube sheet, wherein the diameter of the carbon nanotubes in the carbon nanotube sheet is 0.8 nm or more and 6 nm or less, the length of the carbon nanotubes is 10 μm or more and 10 cm or less, and the carbon content in the carbon nanotubes is 98% by mass or more.

9. The dustproof film as described in claim 8 is a self-supporting film.

10. The dustproof film as claimed in claim 8 or 9, wherein the length-to-diameter ratio (length / diameter) of the carbon nanotube is greater than 1×10⁴ and less than 1×10⁸.

11. The dustproof film for exposure as claimed in claim 8 or 9, further comprising a protective layer in contact with the carbon nanotube sheet.

12. The dustproof film for exposure as claimed in claim 11, wherein the protective layer comprises one or more selected from the group consisting of SiOx (x≦2), SiNb (a / b is 0.7 to 1.5), SiON, Y2O3, YN, Mo, Ru, Rb, Sr, Y, Zr, Nb, B4C, SiC and Rh.

13. A dustproof film assembly comprising: a dustproof film as described in any one of claims 8 to 12; and a support frame supporting the dustproof film.

14. A dustproof film assembly frame comprising: a dustproof film as claimed in any one of claims 8 to 12; and a first frame supporting the dustproof film.

15. A dustproof film assembly comprising: a dustproof film assembly frame as described in claim 14; and a second frame connected to the dustproof film assembly frame.

16. An exposure original comprising: an original; and a dustproof film assembly as described in claim 7 or 13, mounted on the patterned side of said original.

17. An exposure apparatus comprising: an exposure master as described in claim 16.

18. An exposure apparatus comprising: a light source emitting exposure light; an exposure master as described in claim 16; and an optical system for guiding the exposure light emitted from the light source to the exposure master; and configuring the exposure master such that the exposure light emitted from the light source passes through the dustproof film and illuminates the master.

19. The exposure apparatus of claim 18, wherein the exposure light is extreme ultraviolet light.

20. A method for manufacturing a semiconductor device, comprising: The step of causing exposure light emitted from the light source to pass through the dustproof film of the exposure original as described in claim 16 and irradiate the original, and to be reflected by the original; The step of exposing the sensor substrate in a patterned manner by allowing the exposure light reflected from the original to pass through the dustproof film and irradiate the sensor substrate.

21. A method for manufacturing a semiconductor device as claimed in claim 20, wherein the exposure light is extreme ultraviolet light.

22. A method for manufacturing a dustproof film assembly, comprising: Carbon nanotubes are manufactured by chemical vapor deposition in the presence of a metal catalyst, with water vapor at a temperature above 600°C and below 1000°C, at a concentration of 10 ppm to 10000 ppm. The obtained carbon nanotubes are then formed into a film to manufacture a carbon nanotube sheet. The carbon nanotube sheet is then connected to a support frame having an opening in a manner that covers the opening.

23. A method of manufacturing a dustproof film assembly as claimed in claim 22, wherein the metal catalyst is disposed on a substrate.

24. A method for manufacturing a dustproof film assembly, comprising: A metal catalyst is patterned on a substrate. In the presence of the metal catalyst, water vapor at a temperature of 10 ppm to 10,000 ppm is added at a temperature of 600°C to 1000°C. Multiple monolayer carbon nanotubes are formed by chemical vapor deposition to create a carbon nanotube block structure. The carbon nanotube block structure is then deposited into a sheet to create a carbon nanotube sheet. The carbon nanotube sheet is then connected to a support frame with an opening to cover the opening.

Images