Manufacturing method of substrate with multilayer reflective film, reflective photomask substrate, reflective photomask and semiconductor device

Abstract

This invention provides a substrate with a multilayer reflective film, a reflective photomask substrate, a reflective photomask, and a method for manufacturing a semiconductor device. The substrate with the multilayer reflective film can prevent the decrease in reflectivity of the multilayer reflective film due to the formation of silicates in the protective film. The substrate 100 with the multilayer reflective film includes a substrate 10, a multilayer reflective film 12 disposed on the substrate 10, and a protective film 14 disposed on the multilayer reflective film 12. The protective film 14 includes a SiN material layer containing silicon (Si) and nitrogen (N) or a SiC material layer containing silicon (Si) and carbon (C) on the side in contact with the multilayer reflective film 12. The SiN material layer or the SiC material layer contains an oxide of at least one metal selected from magnesium (Mg), aluminum (Al), titanium (Ti), yttrium (Y), and zirconium (Zr).

Description

Technical Field

[0001] This invention relates to a method for manufacturing a substrate with a multilayer reflective film, a reflective photomask substrate, a reflective photomask, and a semiconductor device. Prior Technology

[0002] With the increasing demands for higher density and precision in large-scale integrated circuit (LSI) devices in recent years, the exposure technology using extreme ultraviolet (EUV) light, namely EUV lithography, has become highly anticipated. EUV light refers to light in the soft X-ray region or vacuum ultraviolet region, specifically light with a wavelength of approximately 0.2 to 100 nm.

[0003] A reflective photomask comprises: a multilayer reflective film and an absorber pattern as a patterned absorber film. The multilayer reflective film is formed on a substrate to reflect exposure light; the absorber pattern is formed on the multilayer reflective film to absorb exposure light. Light incident on the reflective photomask mounted on an exposure machine used for pattern transfer on a semiconductor substrate is absorbed in the areas where the absorber pattern is present, and reflected by the multilayer reflective film in the areas where the absorber pattern is absent. The optical image reflected by the multilayer reflective film is transferred onto a semiconductor substrate such as a silicon wafer via a reflective optical system.

[0004] In order to achieve high density and high precision in semiconductor devices using reflective photomasks, the reflective area (the surface of the multilayer reflective film) of the reflective photomask needs to have high reflectivity for EUV light, which is used as the exposure light.

[0005] As a multilayer reflective film, it is generally made by periodically stacking elements with different refractive indices. For example, as a multilayer reflective film for EUV light with a wavelength of 13~14 nm, a Mo / Si periodic stacked film formed by alternating stacking of Mo and Si films for about 40 cycles can be used.

[0006] Patent Document 1 describes a substrate with a multilayer reflective film, which has a multilayer reflective film on the substrate to reflect exposed light. Furthermore, Patent Document 1 describes the formation of a protective film on the multilayer reflective film to protect it; the protective film is formed by sequentially stacking a reflectivity reduction suppression layer, a barrier layer, and an etching stop layer. Also, Patent Document 1 describes the etching stop layer as containing ruthenium (Ru) or an alloy thereof, the reflectivity reduction suppression layer as containing a material selected from silicon (Si), silicon oxide, silicon nitride, and silicon oxynitride, and the barrier layer as containing one or more materials selected from magnesium (Mg), aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), germanium (Ge), zirconium (Zr), niobium (Nb), rhodium (Rh), hafnium (Hf), tantalum (Ta), and tungsten (W).

[0007] Patent Document 2 discloses a substrate with a multilayer reflective film, comprising: a substrate; a multilayer reflective film; and a Ru-based protective film formed on the multilayer reflective film to protect it. Furthermore, Patent Document 2 discloses that the surface layer of the multilayer reflective film opposite to the substrate contains a Si layer, and a barrier layer is provided between the multilayer reflective film and the Ru-based protective film to prevent Si from transferring to the Ru-based protective film. Moreover, Patent Document 2 discloses that the barrier layer contains at least one of the group consisting of at least one metal selected from Ti, Al, Ni, Pt, Pd, W, Mo, Co, and Cu, an alloy of two or more metals, nitrides of these metals, silicates of these metals, and silicon nitrides of these metals, and a gradient region exists between the Si-containing layer and the barrier layer where the content of the metal component constituting the barrier layer continuously decreases towards the substrate. [Previous Technical Documents] [Patent Literature]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2014-170931 [Patent Document 2] International Publication No. 2015 / 012151 Summary of the Invention

[0009] A protective film is formed on the multilayer reflective film to protect it from damage caused by dry etching and cleaning during the manufacturing process of the reflective photomask. This protective film is mostly made of Ru-based materials. On the other hand, from the viewpoint of not reducing the reflectivity of the multilayer reflective film, the top layer of the multilayer reflective film is mostly formed of a Si-containing material.

[0010] When the top layer of a multilayer reflective film contains Si, the Si in the top layer can diffuse into the protective film due to the heating during EUV exposure, resulting in RuSi bonds between Ru and Si in the protective film. Furthermore, the heating during annealing in the fabrication of the reflective photomask substrate can allow atmospheric oxygen (O2) to permeate through the protective film and bond with Si, forming SiO2. When silicates such as RuSi or SiO2 are formed in the protective film, the reflectivity of the multilayer reflective film to EUV light decreases significantly compared to calculated values ​​(assuming no Si diffusion). Additionally, because chemically less stable Si can be exposed on the surface of the multilayer reflective film, the durability of the reflective photomask deteriorates. Moreover, it is known that EUV exposure can lead to exposure contamination, such as carbon film buildup in the reflective photomask. To mitigate these issues, the technique of introducing hydrogen into the exposure atmosphere has been introduced in recent years. When hydrogen gas is introduced into the exposure atmosphere, the absorber film may bulge and peel off from the surface of the protective film, or the protective film may bulge and peel off from the surface of the multilayer reflective film (hereinafter, this phenomenon of film peeling is referred to as "bubbling"). When a SiO2 layer is formed in the protective film, the bubbling resistance (H2 resistance) of the reflective photomask in the exposure machine deteriorates.

[0011] The present invention was made in view of the above circumstances, and its object is to provide a method for manufacturing a substrate with a multilayer reflective film, a reflective photomask substrate, a reflective photomask, and a semiconductor device. The substrate with the multilayer reflective film can prevent the reflectivity of the multilayer reflective film from decreasing due to the formation of silica in the protective film.

[0012] To address the aforementioned issues, the present invention has the following configuration.

[0013] (Composition 1) A substrate with a multilayer reflective film, characterized in that: it comprises a substrate, a multilayer reflective film disposed on the substrate, and a protective film disposed on the multilayer reflective film. The aforementioned protective film includes a SiN material layer containing silicon (Si) and nitrogen (N) or a SiC material layer containing silicon (Si) and carbon (C) on the side in contact with the aforementioned multilayer reflective film. The aforementioned SiN or SiC material layer contains an oxide of at least one metal selected from magnesium (Mg), aluminum (Al), titanium (Ti), yttrium (Y), and zirconium (Zr).

[0014] (Construction 2) The substrate with a multilayer reflective film as described in Construction 1, wherein the metal is selected from at least one of Y and Zr.

[0015] (Construction 3) A substrate with a multilayer reflective film as described in Construction 1 or 2, wherein the protective film contains a Ru-based material layer on the SiN material layer or SiC material layer.

[0016] (Construction 4) A reflective photomask substrate, characterized in that: an absorber film is provided on the protective film of the substrate with multilayer reflective film as described in any one of Constructions 1 to 3.

[0017] (Configuration 5) A reflective photomask, characterized in that: it has an absorber pattern formed by patterning the absorber film of the reflective photomask substrate as described in Configuration 4.

[0018] (Construction 6) A method for manufacturing a semiconductor device, characterized by comprising the following steps: using a reflective photomask as described in Construction 5, performing a photolithography process using an exposure apparatus to form a transfer pattern on a transfer object.

[0019] According to the present invention, a method for manufacturing a substrate with a multilayer reflective film, a reflective photomask substrate, a reflective photomask, and a semiconductor device can be provided. The substrate with the multilayer reflective film can prevent the decrease in reflectivity of the multilayer reflective film due to the formation of silica in the protective film. Simple Explanation of the Diagram

[0020] Figure 1 is a cross-sectional schematic diagram showing an example of a substrate with a multilayer reflective film according to this embodiment. Figure 2 is a cross-sectional schematic diagram showing an example of a reflective photomask substrate according to this embodiment. Figure 3 is a cross-sectional schematic diagram showing another example of the reflective photomask substrate of this embodiment. Figures 4A-E are schematic diagrams illustrating one example of a method for manufacturing a reflective photomask. Figure 5 is a schematic diagram of a pattern transfer device. Implementation

[0021] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Furthermore, the following embodiments are provided to specifically illustrate the present invention and are not intended to limit the invention to its scope.

[0022] Figure 1 is a cross-sectional schematic diagram showing an example of a substrate 100 with a multilayer reflective film according to this embodiment. The substrate 100 with a multilayer reflective film shown in Figure 1 includes a substrate 10, a multilayer reflective film 12 formed on the substrate 10, and a protective film 14 formed on the multilayer reflective film 12. A back conductive film 22 for electrostatic chucks can be formed on the back side of the substrate 10 (the surface opposite to the side where the multilayer reflective film 12 is formed).

[0023] Furthermore, in this specification, the term "on" the substrate or film includes not only cases where it is in contact with the upper surface of the substrate or film, but also cases where it is not in contact with the upper surface of the substrate or film. That is, "on" the substrate or film includes cases where a new film is formed on top of the substrate or film, and cases where other films exist between the new film and the substrate or between the new film and the film. Also, "on" does not necessarily refer to the upper side in the vertical direction. "On" merely indicates the relative positional relationship of the substrate or film, etc.

[0024] <Substrate> The substrate 10 can preferably be made of a material with a low coefficient of thermal expansion in the range of 0±5 ppb / ℃ to prevent heat-induced deformation of the transfer pattern during exposure with EUV light. Materials with this low coefficient of thermal expansion can be, for example, SiO2-TiO2 based glass or multi-component glass-ceramics.

[0025] The main surface of the substrate 10 on the side where the transfer pattern (absorber pattern described later) is formed is preferably processed to improve flatness. By improving the flatness of the main surface of the substrate 10, the positional accuracy and transfer accuracy of the pattern can be improved. For example, in the case of EUV exposure, the flatness of the main surface of the substrate 10 on the side where the transfer pattern is formed is preferably 0.1 μm or less, more preferably 0.05 μm or less, and even more preferably 0.03 μm or less within a 132 mm × 132 mm area. Furthermore, the main surface (back side) on the opposite side to the side where the transfer pattern is formed is fixed to the exposure apparatus by an electrostatic chuck, and the flatness of the main surface on the 142 mm × 142 mm area is preferably 0.1 μm or less, more preferably 0.05 μm or less, and even more preferably 0.03 μm or less. Furthermore, in this specification, flatness refers to the TIR (Total Indicated Reading) value, which represents the amount of surface warping (deformation). TIR is the absolute value of the height difference between the highest position of the substrate surface above the focal plane and the lowest position of the substrate surface below the focal plane, with the substrate surface as the reference and the plane defined by the least flat method as the focal plane.

[0026] When exposed to EUV, the surface roughness of the main surface of the substrate 10 on the side where the transfer pattern is formed is preferably less than 0.1 nm in terms of root mean square roughness (Rq). Furthermore, the surface roughness can be measured using an atomic force microscope.

[0027] The substrate 10 is preferably of high rigidity to prevent the film (multilayer reflective film 12, etc.) formed thereon from deforming due to film stress. The substrate 10 is particularly preferably of a high Young's modulus of 65 GPa or higher.

[0028] Multilayer reflective film The multilayer reflective film 12 is composed of multiple layers periodically deposited with elements of different refractive indices as the main components. Generally, the multilayer reflective film 12 comprises a multilayer film formed by alternatingly depositing thin films of light elements or their compounds as high refractive index materials (high refractive index layers) and thin films of heavy elements or their compounds as low refractive index materials (low refractive index layers) for about 40 to 60 cycles.

[0029] A multilayer reflective film 12 can be formed by sequentially stacking high-refractive-index layers and low-refractive-index layers for multiple cycles, starting from the substrate 10 side. In this case, one (high-refractive-index layer / low-refractive-index layer) stacked structure constitutes one cycle.

[0030] Furthermore, the uppermost layer of the multilayer reflective film 12, that is, the surface layer of the multilayer reflective film 12 opposite to the substrate 10, is preferably a high-refractive-index layer. When high-refractive-index layers and low-refractive-index layers are sequentially deposited from the substrate 10 side, the uppermost layer is a low-refractive-index layer. However, when the low-refractive-index layer is the surface of the multilayer reflective film 12, the surface reflectivity of the multilayer reflective film 12 will decrease because the low-refractive-index layer is easily oxidized. Therefore, it is preferable to form a high-refractive-index layer on top of the uppermost low-refractive-index layer. On the other hand, when low-refractive-index layers and high-refractive-index layers are sequentially deposited from the substrate 10 side, the uppermost layer is a high-refractive-index layer. In this case, the uppermost high-refractive-index layer becomes the surface of the multilayer reflective film 12.

[0031] In this embodiment, the high refractive index layer may be a Si-containing layer. The high refractive index layer may contain elemental Si or a Si compound. The Si compound may contain Si and at least one element selected from the group consisting of B, C, N, O, and H. By using a Si-containing layer as the high refractive index layer, a multilayer reflective film with excellent EUV light reflectivity can be obtained.

[0032] In this embodiment, the low refractive index layer may be a layer containing at least one element selected from the group consisting of Mo, Ru, Rh and Pt, or a gold layer containing an alloy containing at least one element selected from the group consisting of Mo, Ru, Rh and Pt.

[0033] For example, as a multilayer reflective film 12 for EUV light with a wavelength of 13-14 nm, a Mo / Si multilayer film, formed by alternating layers of Mo and Si films for approximately 40-60 cycles, is preferably used. Other multilayer reflective films used in the EUV light region include, for example, Ru / Si periodic multilayer films, Mo / Be periodic multilayer films, Mo compound / Si compound periodic multilayer films, Si / Nb periodic multilayer films, Si / Mo / Ru periodic multilayer films, Si / Mo / Ru / Mo periodic multilayer films, and Si / Ru / Mo / Ru periodic multilayer films. The material of the multilayer reflective film can be selected considering the exposure wavelength.

[0034] Furthermore, materials containing Ru can be used as materials for the low-refractive-index layer, such as elemental Ru, RuRh, RuNb, and RuMo. By including Ru in the low-refractive-index layer, a thinner effective reflective surface can be obtained. When the low-refractive-index layer contains Ru, the stacked structure of the multilayer reflective film 12 preferably has less than 40 cycles, and more preferably less than 35 cycles. Furthermore, the stacked structure preferably has more than 20 cycles, and more preferably more than 25 cycles.

[0035] The reflectivity of this multilayer reflective film 12 alone is, for example, 65% or higher. The upper limit of the reflectivity of the multilayer reflective film 12 is, for example, 73%. Furthermore, the thickness and period of the layers contained in the multilayer reflective film 12 can be selected in a manner that satisfies Bruger's law.

[0036] The multilayer reflective film 12 can be formed by known methods. For example, the multilayer reflective film 12 can be formed by ion beam sputtering.

[0037] For example, when the multilayer reflective film 12 is a Mo / Si multilayer film, a Mo film with a thickness of about 3 nm is formed on the substrate 10 using an ion beam sputtering method with a Mo target. Then, a Si film with a thickness of about 4 nm is formed using a Si target. By repeating this operation, a multilayer reflective film 12 consisting of 40 to 60 cycles of Mo / Si film deposition can be formed. At this time, the surface layer of the multilayer reflective film 12 on the side opposite to the substrate 10 contains a Si layer (Si film). The thickness of one cycle of the Mo / Si film is 7 nm.

[0038] <Protective film> To protect the multilayer reflective film 12 from dry etching and cleaning during the manufacturing process of the reflective photomask 200, a protective film 14 can be formed on or in contact with the surface of the multilayer reflective film 12. Furthermore, the protective film 14 also functions to protect the multilayer reflective film 12 when using an electron beam (EB) to correct black defects in the transfer pattern (absorber pattern). Because the protective film 14 is formed on the multilayer reflective film 12, damage to the surface of the multilayer reflective film 12 during the manufacturing of the reflective photomask 200 can be suppressed. As a result, the reflectivity characteristics of the multilayer reflective film 12 for EUV light become excellent.

[0039] The protective film 14 can be formed using known methods. Examples of methods for forming the protective film 14 include ion beam sputtering, magnetron sputtering, reactive sputtering, chemical vapor deposition (CVD), and vacuum evaporation.

[0040] In the substrate 100 with a multilayer reflective film in this embodiment, the protective film 14 includes: a Si material layer 16 on the side in contact with the multilayer reflective film 12, and a protective layer 18 formed on the Si material layer 16.

[0041] In the substrate 100 with a multilayer reflective film in this embodiment, the Si material layer 16 is a SiN material layer containing silicon (Si) and nitrogen (N), or a SiC material layer containing silicon (Si) and carbon (C).

[0042] The SiN material layer is a layer containing silicon (Si) and nitrogen (N). The SiN material layer may further contain other elements, such as O, C, B, and / or H. For example, the SiN material layer may contain at least one material selected from silicon nitride (SixNy (x and y are integers of 1 or more)) and silicon oxynitride (SixOyNz (x, y, and z are integers of 1 or more)). The SiN material layer may also contain at least one material selected from SiN, Si3N4, and SiON.

[0043] The SiC material layer is a layer containing silicon (Si) and carbon (C). The SiC material layer may further contain other elements, such as O, N, B and / or H. For example, the SiC material layer contains silicon carbide (SiC).

[0044] When the high refractive index layer of the multilayer reflective film 12 is a Si film, and a low refractive index layer (e.g., a Mo film) and a high refractive index layer (Si film) are sequentially deposited from the substrate 10 side, the Si material layer 16 can also be a SiN material layer or a SiC material layer, which serves as the uppermost high refractive index layer of the multilayer reflective film 12. Furthermore, when a low refractive index layer and a high refractive index layer (Si film) are sequentially deposited from the substrate 10 side, a high refractive index layer (Si film) can also be provided as the uppermost layer of the multilayer reflective film 12, and a SiN material layer or a SiC material layer can be disposed on it.

[0045] In the substrate 100 with a multilayer reflective film of this embodiment, the SiN material layer or SiC material layer is characterized by containing an oxide of at least one metal selected from magnesium (Mg), aluminum (Al), titanium (Ti), yttrium (Y), and zirconium (Zr). By containing an oxide of at least one metal selected from these metals in the SiN material layer or SiC material layer, the formation of silicates such as RuSi and SiO2 in the protective film 14 can be prevented.

[0046] When Si contained in the Si material layer 16 diffuses into the protective layer 18 due to heating during EUV exposure, metals (e.g., Ru) contained in the protective layer 18 may bond with Si to form metal silicides. When metal silicides are formed in the protective layer 18, there is a problem that the reflectivity of the multilayer reflective film 12 to EUV light decreases significantly compared to the calculated value (assuming no Si diffusion). According to the substrate 100 with the multilayer reflective film of this embodiment, since the Si material layer 16 is a SiN material layer or a SiC material layer, Si diffusion into the protective layer 18 can be prevented, thus preventing the formation of metal silicides (e.g., RuSi) in the protective layer 18. As a result, the reflectivity of the multilayer reflective film 12 to EUV light is prevented from decreasing significantly compared to the calculated value.

[0047] During the annealing process in the fabrication of the reflective photomask substrate, atmospheric oxygen (O2) can penetrate the protective layer 18 and bond with Si, forming a SiO2-containing layer. When a SiO2 layer forms in the protective film 14, the reflective photomask's resistance to blistering (H2 resistance) deteriorates in the exposure machine. The substrate 100 with a multilayer reflective film according to this embodiment prevents the formation of a SiO2 layer in the protective film 14. As a result, the reflective photomask's resistance to blistering (H2 resistance) deteriorates in the exposure machine.

[0048] The formation of a SiO2 layer in the protective film 14 can be prevented for the following reasons.

[0049] As described above, the SiN or SiC material layer constituting the Si material layer 16 contains an oxide of at least one metal selected from magnesium (Mg), aluminum (Al), titanium (Ti), yttrium (Y), and zirconium (Zr). The relationship between the standard formation free energy (ΔG) of the oxides of these metals and the standard formation free energy (ΔG) of SiO2 is as follows. SiO2>TiO2>ZrO2>Al2O3>MgO>Y2O3

[0050] Therefore, the tendency for oxygen (O2) in the atmosphere through the protective layer 18 to bond with at least one of the aforementioned metal elements to form metal oxides is stronger than that of Si, and thus it is believed that the formation of SiO2 can be suppressed.

[0051] Furthermore, according to the substrate 100 with the multilayer reflective film of this embodiment, since Si with low chemical stability is exposed on the surface of the multilayer reflective film 12, the durability of the reflective photomask can be prevented from deteriorating.

[0052] The metal oxide contained in the SiN or SiC material layer is preferably an oxide selected from at least one metal element selected from Y and Zr. The extinction coefficient (k) of Y and Zr for light with a wavelength of 13.5 nm is as low as 0.01 or less. Therefore, when the SiN or SiC material layer contains oxides of such metals, the reflectivity of the multilayer reflective film 12 for EUV light hardly decreases.

[0053] The SiN material layer 16 is preferably formed by PVD (Physical Vapor Deposition) (e.g., magnetron sputtering) using a SiN sintered body as a target. When fabricating the SiN sintered body, it is preferable to add an oxide of at least one metal selected from magnesium (Mg), aluminum (Al), titanium (Ti), yttrium (Y), and zirconium (Zr) as a sintering aid. By adding the sintering aid, a higher density SiN sintered body can be formed. By using a higher density SiN sintered body as a target, a high-quality SiN material layer with fewer defects can be formed. The SiN material layer thus formed contains the oxide of the aforementioned metal added as a sintering aid.

[0054] The SiC material layer 16 is preferably formed by PVD (e.g., magnetron sputtering) using a SiC sintered body as a target. When fabricating the SiC sintered body, it is preferable to add an oxide of at least one metal selected from magnesium (Mg), aluminum (Al), titanium (Ti), yttrium (Y), and zirconium (Zr) as a sintering aid. By adding the sintering aid, a higher density SiC sintered body can be formed. By using a higher density SiC sintered body as a target, a high-quality SiC material layer with fewer defects can be formed. The SiC material layer thus formed contains the oxide of the aforementioned metal added as a sintering aid.

[0055] The SiN or SiC material layer can be fabricated as a single layer. Here, "single layer" refers to a SiN or SiC material layer where the content (atomic percentage) of the metal (selected from at least one metal from Mg, Al, Ti, Y, and Zr) is approximately fixed throughout the entire thickness direction of the film (within ±20 atomic percent, preferably within ±10 atomic percent). Furthermore, the SiN or SiC material layer can be fabricated as a tilted film (a film where the metal content continuously varies along the thickness direction). Regarding the SiN or SiC material layer, it is preferable that the side in contact with the protective layer 18 has a higher content of metal oxides than the side in contact with the multilayer reflective film 12. In this case, Si diffusion into the protective layer 18 can be more effectively prevented when the substrate 100 with the multilayer reflective film is heated.

[0056] A protective layer 18 is formed on the Si material layer 16. The protective layer 18 can be formed using known methods. Examples of methods for forming the protective layer 18 include ion beam sputtering, magnetron sputtering, reactive sputtering, chemical vapor deposition (CVD), and vacuum evaporation.

[0057] The protective layer 18 is preferably formed of a material with an etching selectivity different from that of the absorber film 24, which will be described later. Examples of materials for the protective layer 18 include: Ru, Ru-(Nb, Rh, Zr, Y, B, Ti, La, Mo), Si-(Ru, Rh, Cr, B), Si, Zr, Nb, La, and B. The protective layer 18 is particularly preferably a Ru-based material layer containing ruthenium (Ru). Specifically, the material of the protective layer 18 is preferably Ru or Ru-(Nb, Rh, Zr, Y, B, Ti, La, Mo). This protective layer 18 is particularly effective when the absorber film 24 is formed of a Ta-based material and the absorber film 24 is patterned by dry etching using a Cl-based gas.

[0058] The protective layer 18 may further contain at least one element selected from the group consisting of nitrogen (N), oxygen (O), carbon (C) and boron (B).

[0059] The multilayer reflective film 12, the Si material layer 16, and the protective layer 18 can be formed using the same method, or they can be formed using different methods. For example, after forming the multilayer reflective film 12 using ion beam sputtering, the Si material layer 16 and the protective layer 18 can be formed continuously using magnetron sputtering. Alternatively, after forming the multilayer reflective film 12 and the Si material layer 16 continuously using ion beam sputtering, the protective layer 18 can be formed using magnetron sputtering. Or, the multilayer reflective film 12 can be formed continuously until the protective layer 18 is formed using ion beam sputtering. When forming these films, a single target or two or more targets can be used. Furthermore, the substrate with the multilayer reflective film 12, the Si material layer 16, and the protective layer 18 can be subjected to a heat treatment at 100°C to 300°C in an atmospheric atmosphere or a nitrogen atmosphere to alleviate the film stress of the multilayer reflective film 12.

[0060] The nitrogen (N) content in the SiN material layer is preferably 20 atomic% to 70 atomic%, more preferably 40 atomic% to 60 atomic%. When the N content in the SiN material layer is less than 20 atomic%, the effect of preventing Si diffusion into the protective layer 18 cannot be fully achieved. When the N content in the SiN material layer exceeds 70 atomic%, the film density of the SiN material layer decreases, the durability deteriorates, and the reflectivity also decreases.

[0061] The C content in the SiC material layer is preferably 20 atomic% to 80 atomic%, more preferably 40 atomic% to 70 atomic%. When the C content in the SiC material layer is less than 20 atomic%, the effect of preventing Si diffusion into the protective layer 18 cannot be fully achieved. When the C content in the SiC material layer exceeds 80 atomic%, the film density of the SiC material layer becomes lower, and the durability deteriorates.

[0062] As described above, the Si material layer 16 (SiN material layer or SiC material layer) contains an oxide of at least one metal selected from magnesium (Mg), aluminum (Al), titanium (Ti), yttrium (Y), and zirconium (Zr). The oxygen (O) content in the SiN material layer is preferably 0.5 atomic% to 20 atomic%, more preferably 1.5 atomic% to 15 atomic%. When the O content in the SiN material layer is less than 0.5 atomic%, the formation of SiO2 cannot be suppressed, and durability decreases. When the O content in the SiN material layer exceeds 20 atomic%, the reflectivity of the multilayer reflective film will decrease sharply. The oxygen (O) content in the SiC material layer is preferably 0.1 atomic% to 15 atomic%, more preferably 0.2 atomic% to 12 atomic%. When the O content in the SiC material layer is less than 0.1 atomic%, the formation of SiO2 cannot be suppressed, and durability decreases. When the oxygen content in the SiC material layer exceeds 15 atomic%, the reflectivity of the multilayer reflective film will decrease sharply.

[0063] Furthermore, the content of the aforementioned metal (selected from at least one metal from Mg, Al, Ti, Y, and Zr) in the SiN material layer is preferably 0.1 atomic% to 10 atomic%, more preferably 0.5 atomic% to 6.0 atomic%. When the content of the aforementioned metal in the SiN material layer is less than 0.1 atomic%, the formation of SiO2 cannot be suppressed, and durability decreases. When the content of the aforementioned metal in the SiN material layer exceeds 10 atomic%, the reflectivity of the multilayer reflective film will decrease sharply. The content of the aforementioned metal (selected from at least one metal from Mg, Al, Ti, Y, and Zr) in the SiC material layer is preferably 0.05 atomic% to 3.0 atomic%, more preferably 0.1 atomic% to 2.5 atomic%. When the content of the aforementioned metal in the SiC material layer is less than 0.05 atomic%, the formation of SiO2 cannot be suppressed, and durability decreases. When the content of the aforementioned metal in the SiC material layer exceeds 3.0 atomic%, the reflectivity of the multilayer reflective film will decrease sharply.

[0064] Figure 2 is a cross-sectional schematic diagram showing an example of the reflective photomask substrate 110 of this embodiment. The reflective photomask substrate 110 shown in Figure 2 has an absorber film 24 for absorbing EUV light on the protective film 14 of the substrate 100 with the aforementioned multilayer reflective film. Furthermore, the reflective photomask substrate 110 may further have other thin films such as a resist film 26 on the absorber film 24.

[0065] Figure 3 is a cross-sectional schematic diagram showing another example of the reflective photomask substrate 110 of this embodiment. As shown in Figure 3, the reflective photomask substrate 110 may have an etched photomask film 28 between the absorber film 24 and the resist film 26.

[0066] <Absorbent membrane> In this embodiment, the absorber film 24 of the reflective photomask substrate 110 is formed on the protective film 14. The basic function of the absorber film 24 is to absorb EUV light. The absorber film 24 can be an absorber film 24 designed to absorb EUV light, or it can be an absorber film 24 with a phase shifting function that also takes into account the phase difference of EUV light. An absorber film 24 with a phase shifting function refers to one that absorbs EUV light and reflects a portion of EUV light to achieve phase shifting. That is, in the reflective photomask 200 formed by patterning the absorber film 24 with a phase shifting function, the portion where the absorber film 24 is formed absorbs EUV light for light reduction, and reflects a portion of EUV light at a level that does not adversely affect the pattern transfer. Furthermore, in the area where the absorber film 24 is not formed (field region), EUV light is reflected by the multilayer reflective film 12 via the protective film 14. Therefore, the required phase difference is generated between the reflected light from the absorber film 24 with a phase shifting function and the reflected light from the field region. The absorber film 24 with phase shifting function is preferably formed such that the phase difference between the reflected light from the absorber film 24 and the reflected light from the multilayer reflective film 12 reaches 170 to 190 degrees. The light with a phase difference of about 180 degrees interferes with each other at the edge of the pattern, thereby improving the image contrast of the projected optical image. The resolution increases with the improvement of the image contrast, thereby increasing various exposure-related margins such as exposure margin and focus margin.

[0067] The absorber film 24 can be a single-layer film or a multilayer film comprising multiple films (e.g., a lower absorber film and an upper absorber film). In the case of a single-layer film, the number of steps in manufacturing the photomask substrate can be reduced, thereby improving production efficiency. In the case of a multilayer film, its optical constants and film thickness can be appropriately set so that the upper absorber film becomes an anti-reflective film when using light to inspect defects in the photomask pattern. This improves the inspection sensitivity when using light to inspect defects in the photomask pattern. Furthermore, when the upper absorber film uses films containing oxygen (O) and nitrogen (N) that enhance oxidation resistance, its stability over time is improved. Thus, by making the absorber film 24 into a multilayer film, various functions can be added to the absorber film 24. When the absorber film 24 has a phase shifting function, the adjustment range on the optical surface can be increased by making it into a multilayer film, thereby making it easier to obtain the desired reflectivity.

[0068] The material of the absorber film 24 is not particularly limited, as long as it has the function of absorbing EUV light and can be processed by etching (preferably by dry etching using chlorine (Cl) and / or fluorine (F) based gases), and has a relatively high selectivity for etching compared to the protective film 14. Preferably, the material with this function is selected from at least one metal or a compound (alloy) of palladium (Pd), silver (Ag), platinum (Pt), gold (Au), iridium (Ir), tungsten (W), chromium (Cr), cobalt (Co), manganese (Mn), tin (Sn), tantalum (Ta), vanadium (V), nickel (Ni), hafnium (Hf), iron (Fe), copper (Cu), tellurium (Te), zinc (Zn), magnesium (Mg), germanium (Ge), aluminum (Al), rhodium (Rh), ruthenium (Ru), molybdenum (Mo), niobium (Nb), titanium (Ti), zirconium (Zr), yttrium (Y), and silicon (Si).

[0069] The absorber film 24 can be formed using magnetron sputtering methods such as DC sputtering and RF sputtering. For example, the absorber film 24, such as tantalum compound, can be formed by reactive sputtering, which uses a target containing tantalum and boron and argon gas with added oxygen or nitrogen.

[0070] The tantalum compound used to form the absorber film 24 comprises an alloy of Ta and the aforementioned metals. When the absorber film 24 is an alloy of Ta, in terms of smoothness and flatness, the crystalline state of the absorber film 24 is preferably amorphous or microcrystalline. When the surface of the absorber film 24 is not smooth or flat, the edge roughness of the absorber pattern 24a may increase, and the dimensional accuracy of the pattern may deteriorate. The preferred surface roughness of the absorber film 24, expressed as root mean square roughness (RMS), is 0.5 nm or less, more preferably 0.4 nm or less, and even more preferably 0.3 nm or less.

[0071] Examples of tantalum compounds used to form the absorber membrane 24 include: compounds containing Ta and B; compounds containing Ta and N; compounds containing Ta, O and N; compounds containing Ta, B and further containing at least one of O and N; compounds containing Ta and Si; compounds containing Ta, Si and N; compounds containing Ta and Ge; and compounds containing Ta, Ge and N, etc.

[0072] Ta has a high absorption coefficient for EUV light and can be easily dry-etched using chlorine or fluorine gases. Therefore, Ta is a material with excellent processability for the absorber film 24. Furthermore, by adding B, Si, and / or Ge to Ta, amorphous materials can be easily obtained. As a result, the smoothness of the absorber film 24 can be improved. In addition, if N and / or O are added to Ta, the oxidation resistance of the absorber film 24 will be improved, thus enhancing its stability over time.

[0073] <Etching photomask> An etching mask 28 may be formed on the absorber film 24. Preferably, the material used for the etching mask 28 is one with a higher etch selectivity than the absorber film 24. The etch selectivity of the absorber film 24 relative to the etching mask 28 is preferably 1.5 or higher, and more preferably 3 or higher.

[0074] In this embodiment, the reflective photomask substrate 110 preferably has an etchable photomask film 28 containing chromium (Cr) on the absorber film 24. When etching the absorber film 24 using a fluorine-based gas, chromium or a chromium compound is preferably used as the material for the etchable photomask film 28. Examples of chromium compounds include materials containing Cr and at least one element selected from N, O, C, and H. The etchable photomask film 28 is more preferably containing CrN, CrO, CrC, CrON, CrOC, CrCN, or CrOCN, and even more preferably a CrO-based film (CrO film, CrON film, CrOC film, or CrOCN film) containing chromium and oxygen.

[0075] When etching the absorber film 24 using a substantially oxygen-free chlorine-based gas, silicon or silicon compounds are preferably used as the material for etching the photomask film 28. Examples of silicon compounds include: materials containing Si and at least one element selected from N, O, C, and H; metallic silicon (metal silicates) containing a metal in silicon and silicon compounds; and metallic silicon compounds (metal silicate compounds). Examples of metallic silicon compounds include materials containing a metal, Si, and at least one element selected from N, O, C, and H.

[0076] The thickness of the etched photomask 28 is preferably 3 nm or more to form the pattern accurately on the absorber film 24. Furthermore, in order to reduce the thickness of the resist film 26, the thickness of the etched photomask 28 is preferably 15 nm or less.

[0077] <Back Conductive Film> A back conductive film 22 for electrostatic chucks can be formed on the back side of the substrate 10 (the surface opposite to the side where the multilayer reflective film 12 is formed). When used for electrostatic chucks, the sheet resistance required for the back conductive film 22 is typically below 100 Ω / □ (Ω / square). The back conductive film 22 can be formed, for example, by magnetron sputtering or ion beam sputtering using a target containing a metal such as chromium or tantalum or an alloy thereof. The material of the back conductive film 22 is preferably a material containing chromium (Cr) or tantalum (Ta). For example, the material of the back conductive film 22 is preferably a Cr compound containing at least one selected from boron, nitrogen, oxygen and carbon. Examples of Cr compounds include CrN, CrON, CrCN, CrCON, CrBN, CrBON, CrBCN and CrBOCN. Furthermore, the material of the back conductive film 22 is preferably Ta (tantalum), a Ta-containing alloy, or a Ta compound containing at least one selected from boron, nitrogen, oxygen and carbon. Examples of Ta compounds include TaB, TaN, TaO, TaON, TaCON, TaBN, TaBO, TaBON, TaBCON, TaHf, TaHfO, TaHfN, TaHfON, TaHfCON, TaSi, TaSiO, TaSiN, TaSiON, and TaSiCON.

[0078] The thickness of the conductive film 22 on the back is not particularly limited, as long as it functions as a film for electrostatic chucks, for example, it can be 10 nm to 200 nm.

[0079] <Reflective Photomask> Using the reflective photomask substrate 110 of this embodiment, the reflective photomask 200 of this embodiment can be manufactured. Hereinafter, an example of a method for manufacturing a reflective photomask will be described.

[0080] Figures 4A-E are schematic diagrams illustrating one example of a manufacturing method for a reflective photomask 200.

[0081] As shown in Figures 4A-E, firstly, a reflective photomask substrate 110 is prepared, which includes a substrate 10; a multilayer reflective film 12 formed on the substrate 10; a protective film 14 (Si material layer 16 and protective layer 18) formed on the multilayer reflective film 12; and an absorber film 24 formed on the protective film 14 (Figure 4A). Next, a resist film 26 is formed on the absorber film 24 (Figure 4B). A pattern is drawn on the resist film 26 using an electron beam plotting apparatus, and then a resist pattern 26a is formed through development and rinsing steps (Figure 4C).

[0082] Using the resist pattern 26a as a photomask, the absorber film 24 is dry-etched. In this way, the portion of the absorber film 24 not covered by the resist pattern 26a is etched to form the absorber pattern 24a (Fig. 4D).

[0083] The etching gas used as the absorber membrane 24 can be, for example, a fluorine-based gas and / or a chlorine-based gas. Fluorine-based gases include CF4, CHF3, C2F6, C3F6, C4F6, C4F8, CH2F2, CH3F, C3F8, SF6, and F2. Chlorine-based gases include Cl2, SiCl4, CHCl3, CCl4, and BCl3. Furthermore, a mixture of fluorine-based and / or chlorine-based gases and O2 in a specific proportion can be used. These etching gases may further contain inert gases such as He and / or Ar, if necessary.

[0084] After forming the absorber pattern 24a, the resist pattern 26a is removed using a resist stripping solution. After removing the resist pattern 26a, a wet cleaning step using an acidic or alkaline aqueous solution is performed, thereby obtaining the reflective photomask 200 of this embodiment (Fig. 4E).

[0085] Furthermore, when using a reflective photomask substrate 110 on which an etched photomask film 28 is formed on the absorber film 24, after using the resist pattern 26a as a photomask to form a pattern (etched photomask pattern) on the etched photomask film 28, an additional step is added to form a pattern on the absorber film 24 using the etched photomask pattern as a photomask.

[0086] The reflective photomask 200 thus obtained has a structure in which multiple reflective films 12, protective films 14 (Si material layer 16 and protective layer 18) and absorber pattern 24a are deposited on the substrate 10.

[0087] The exposed area 30 of the multilayer reflective film 12 (including the protective film 14) has the function of reflecting EUV light. The area 32 of the multilayer reflective film 12 (including the protective film 14) covered by the absorber pattern 24a has the function of absorbing EUV light. According to the reflective photomask 200 of this embodiment, the thickness of the absorber pattern 24a can be thinner than before, so that the reflectivity can reach, for example, 2.5% or less, and thus finer patterns can be transferred onto the substrate.

[0088] <Semiconductor Device Manufacturing Methods> By using photolithography with the reflective photomask 200 of this embodiment, a transfer pattern can be formed on a semiconductor substrate. This transfer pattern has a shape in which the reflective photomask 200 has been transferred. By forming a transfer pattern on the semiconductor substrate using the reflective photomask 200, a semiconductor device can be manufactured.

[0089] Using Figure 5, a method for transferring a pattern onto a semiconductor substrate 56 coated with resist using EUV light will be described.

[0090] Figure 5 shows the pattern transfer apparatus 50. The pattern transfer apparatus 50 includes a laser plasma X-ray source 52, a reflective photomask 200, and a reduction optical system 54. As the reduction optical system 54, an X-ray reflector is used.

[0091] The pattern reflected by the reflective photomask 200 is reduced to approximately one-quarter of its normal size by the reduction optical system 54. For example, the exposure wavelength is preset to be 13-14 nm, and the optical path is in a vacuum. Under these conditions, EUV light generated by the laser plasma X-ray source 52 is incident on the reflective photomask 200. The light reflected by the reflective photomask 200 is transferred via the reduction optical system 54 onto a semiconductor substrate 56 coated with resist.

[0092] Light reflected by the reflective photomask 200 is incident on the reduction optical system 54. The light incident on the reduction optical system 54 forms a transfer pattern on the resist layer on the resist-coated semiconductor substrate 56. By developing the exposed resist layer, a resist pattern can be formed on the resist-coated semiconductor substrate 56. By using the resist pattern as a photomask to etch the semiconductor substrate 56, a specific wiring pattern can be formed on the semiconductor substrate. Through these steps and other necessary steps, a semiconductor device is manufactured. [Example]

[0093] Hereinafter, the embodiments, reference examples and comparative examples will be described with reference to the drawings.

[0094] (Fabrication of substrate 100 with multilayer reflective film attached) First, a substrate 10 with dimensions of 6025 (approximately 152 mm × 152 mm × 6.35 mm) with its first and second main surfaces polished is prepared. This substrate 10 is a substrate containing low thermal expansion glass (SiO2-TiO2 based glass). The main surfaces of the substrate 10 are polished by rough polishing, fine polishing, local processing, and contact polishing.

[0095] Subsequently, a multilayer reflective film 12 is formed on the main surface (first main surface) of the substrate 10. Regarding the multilayer reflective film 12 formed on the substrate 10, in order to make it suitable for EUV light with a wavelength of 13.5 nm, a periodic multilayer reflective film 12 comprising Mo and Si is fabricated. The multilayer reflective film 12 is formed by alternatingly depositing Mo and Si films on the substrate 10 using an ion beam sputtering method with a Mo target and a Si target and krypton (Kr) as the processing gas. First, a Si film is formed with a thickness of 4.2 nm, followed by a Mo film with a thickness of 2.8 nm. This is considered one cycle, and 40 cycles are deposited in the same manner to form the multilayer reflective film 12.

[0096] Subsequently, a Si material layer 16 is formed on the multilayer reflective film 12. The Si material layer 16 is formed to a thickness of 3.5 nm using a target comprising a SiC sintered body or a SiN sintered body, by magnetron sputtering in an Ar gas atmosphere. Furthermore, an oxide of at least one metal selected from magnesium (Mg), aluminum (Al), yttrium (Y), and zirconium (Zr) is added as a sintering aid to the SiC sintered body or SiN sintered body used as the target. On the other hand, in Reference Example 1, a SiN sintered body is used as the target to form the Si material layer. No sintering aid is added to the target. In Reference Example 2, a SiC sintered body is used as the target to form the Si material layer. No sintering aid is added to the target. In Comparative Example 1, elemental Si is used as the target to form the Si material layer.

[0097] Subsequently, a RuNb film is formed on the Si material layer 16 as a protective layer 18. The protective layer 18 is formed with a thickness of 3.5 nm using a RuNb target and magnetron sputtering in an Ar gas atmosphere.

[0098] (Evaluation of substrate 100 with multilayer reflective film attached) Using the substrate 100 with multilayer reflective film from the above-described embodiments, reference examples, and comparative examples, we confirmed whether there was a change in reflectivity after heating the substrate 100 with multilayer reflective film, and whether a SiO2 layer was formed in the protective film 14.

[0099] Specifically, firstly, the reflectivity of the substrate 100 with a multilayer reflective film attached to EUV light was measured for the embodiments, reference examples, and comparative examples. Next, the substrate 100 with the multilayer reflective film attached was heated at 200°C for 10 minutes in an atmospheric atmosphere. After heating the substrate 100 with the multilayer reflective film attached, the reflectivity of the substrate 100 with the multilayer reflective film attached to EUV light was measured. The change in reflectivity of the substrate 100 with the multilayer reflective film attached was evaluated by subtracting the reflectivity (%) of the substrate 100 with the multilayer reflective film attached before heating from the reflectivity (%) of the substrate 100 with the multilayer reflective film attached after heating.

[0100] Furthermore, after heating the substrate 100 with the multilayer reflective film at 200°C for 10 minutes, the cross-section of the protective film 14 was observed using an electron microscope to confirm whether a SiO2 layer was formed in the protective film 14.

[0101] Table 1 below shows the confirmation results regarding whether there was a change in the reflectivity of the substrate 100 with the multilayer reflective film and whether a SiO2 layer was formed in the protective film 14. Table 1 also shows the film composition and thickness of the Si material layer 16 in the examples, reference examples, and comparative examples after heating the substrate 100 with the multilayer reflective film. The film composition and metal oxides of the Si material layer 16 were determined by X-ray photoelectron spectrometry (XPS) and dynamic SIMS (secondary ion mass analysis). Furthermore, the composition of the RuNb film was determined by X-ray photoelectron spectrometry (XPS), and the result was Ru:Nb = 80:20.

[0102] [Table 1] Si material layer Reflectivity change (%) Whether or not a SiO2 layer is formed target Additives Membrane composition Film thickness(nm) Example 1 SiN Mg SiNMgO (35:47:5:13) 3.5 -0.3 none Example 2 SiN Al SiNAlO (38:51:1:10) 3.5 -0.3 none Example 3 SiN Y SiNYO (38:50:2:10) 3.5 -0.2 none Example 4 SiN Zr SiNZrO (38:51:1:10) 3.5 -0.2 none Example 5 SiC Mg SiCMgO (45:45:2:8) 3.5 -0.7 none Example 6 SiC Al SiCAlO (46:46:1:7) 3.5 -0.8 none Example 7 SiC Y SiCYO (46:46:1:7) 3.5 -0.7 none Example 8 SiC Zr SiCZrO (46:46:1:7) 3.5 -0.7 none Reference Example 1 SiN - SiNO (39:53:8) 3.5 -0.5 have See Example 2 SiC - SiCO (47:47:6) 3.5 -1.0 have Comparative Example 1 Si - SiO (79:21) 3.5 -2.2 have

[0103] As shown in Table 1, the substrates 100 with multilayer reflective films in Examples 1-8 and Reference Examples 1 and 2 showed almost no change in reflectivity for EUV light before and after heating at 200°C. The changes in reflectivity were particularly small in Examples 3 and 4. This is presumably because, in Examples 1-8 and Reference Examples 1 and 2, the Si material layer 16 was a SiN layer or a SiC layer, which suppressed the diffusion of Si from the Si material layer 16 into the protective layer 18, thereby inhibiting the formation of metal silicide (RuSi) in the protective layer 18.

[0104] On the other hand, regarding the substrate 100 with a multilayer reflective film in Comparative Example 1, the reflectivity of the substrate 100 with a multilayer reflective film to EUV light changed significantly before and after heating at 200°C. It is inferred that the reason is that in Comparative Example 1, Si diffused from the Si material layer 16 into the protective layer 18, thus forming a metal silicate (RuSi) in the protective layer 18.

[0105] Furthermore, regarding the substrate 100 with multilayer reflective films in Examples 1-8, no SiO2 layer was formed in the protective film 14 after heating at 200°C. This is presumed to be because, in Examples 1-8, metal oxides were added to the Si material layer 16, thus suppressing the formation of SiO2 in the protective film 14. On the other hand, regarding the substrate 100 with multilayer reflective films in Reference Examples 1, 2, and Comparative Example 1, a SiO2 layer was formed in the protective film 14 after heating at 200°C. This is presumed to be because, in Reference Examples 1, 2, and Comparative Example 1, no metal oxides were added to the Si material layer 16, thus forming SiO2 in the protective film 14.

[0106] 10:Substrate 12: Multilayer reflective film 14: Protective film 16: Si material layer 18: Protective layer 22: Backside conductive film 24: Absorbent membrane 24a: Absorber pattern 26: Anti-corrosion film 26a: Anti-corrosion pattern 28: Etching the photomask film 30: Area of ​​exposed multilayer reflective film 12 (including protective film 14) 32: The area covered by the absorber pattern 24a of the multilayer reflective film 12 (including the protective film 14). 50: Pattern transfer device 52: Laser Plasma X-ray Source 54: Miniaturization of optical systems 56: Semiconductor substrate 100: Substrate with multilayer reflective film 110: Reflective photomask substrate 200: Reflective photomask

Claims

1. A substrate with a multilayer reflective film, characterized in that: it comprises a substrate, a multilayer reflective film disposed on the substrate and reflecting EUV light, and a protective film disposed on the multilayer reflective film, wherein the protective film comprises a SiN material layer containing silicon (Si) and nitrogen (N) or a SiC material layer containing silicon (Si) and carbon (C) on the side in contact with the multilayer reflective film, and the SiN material layer or SiC material layer contains an oxide of at least one metal selected from magnesium (Mg), aluminum (Al), titanium (Ti), yttrium (Y) and zirconium (Zr).

2. The substrate with a multilayer reflective film as claimed in claim 1, wherein the protective film comprises the SiN material layer.

3. The substrate with a multilayer reflective film as claimed in claim 2, wherein the content of the metal in the SiN material layer is 0.1 atomic% to 10 atoms.

4. The substrate with a multilayer reflective film as claimed in claim 2, wherein the oxygen content of the SiN material layer is 0.5 atomic% to 20 atomic%.

5. The substrate with a multilayer reflective film as claimed in claim 2, wherein the nitrogen content in the SiN material layer is 20 atomic% to 70 atomic%.

6. The substrate with a multilayer reflective film as claimed in claim 1, wherein the protective film comprises the SiC material layer.

7. The substrate with a multilayer reflective film as claimed in claim 6, wherein the content of the metal in the SiC material layer is 0.05 atomic% to 3.0 atomic%.

8. The substrate with a multilayer reflective film as claimed in claim 6, wherein the oxygen content of the SiC material layer is 0.1 atomic% to 15 atomic%.

9. The substrate with a multilayer reflective film as claimed in claim 6, wherein the carbon content of the SiC material layer is 20 atomic% to 80 atomic%.

10. The substrate with a multilayer reflective film as claimed in claim 1, wherein the protective film comprises a Ru-based material layer on the SiN material layer or the SiC material layer.

11. A reflective photomask substrate, characterized in that: an absorber film is provided on the protective film of the substrate with multilayer reflective film as claimed in any one of claims 1 to 10.

12. A reflective photomask, characterized in that it comprises an absorber pattern formed by patterning the absorber film of the reflective photomask substrate as claimed in claim 11.

13. A method for manufacturing a semiconductor device, characterized by comprising the following steps: using a reflective photomask as claimed in claim 12 and performing a photolithography process using an exposure apparatus to form a transfer pattern on a transfer object.

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