Substrate with multilayer reflective film, reflective mask blank, reflective mask, and method for manufacturing semiconductor device

Abstract

Provided is a substrate with a multilayer reflective film having a protective film, the substrate having a first layer and a second layer, and maintaining reflectance to EUV light even under a high-temperature heat treatment by suppressing thermal diffusion of the protective film.　This substrate with a multilayer reflective film has a protective film including a first layer on the multilayer reflective film and a second layer in contact with the first layer. The first layer and the second layer of the protective film include silicon (Si), and the P value of the protective film is 1.5-10.0. The P value is calculated on the basis of an Si2p spectrum analyzed by X-ray photoelectron spectroscopy, and is defined as P = (SSiX / SSi) × (uSiX-uSi), SiX being a compound of Si, SSi being the area of the Si-derived peak in the Si2p spectrum, SSiXbeing the area of the SiX-derived peak in the Si2p spectrum, uSi being the position of the Si-derived peak, and uSiX being the position of the SiX-derived peak.

Description

Substrate with multilayer reflective film, reflective mask blank, reflective mask, and method for manufacturing semiconductor device

[0001] The present invention relates to a reflective mask used in the manufacture of a semiconductor device, a multilayer reflective film-coated substrate used for the manufacture of a reflective mask, and a reflective mask blank. The present invention also relates to a method for manufacturing a semiconductor device using the reflective mask.

[0002] 2. Description of the Related Art In recent years, with the increasing demand for higher density and higher precision in VLSI devices, EUV lithography, an exposure technique using extreme ultraviolet (hereinafter referred to as EUV) light, has been proposed.

[0003] A reflective mask has a multilayer reflective film formed on a substrate to reflect exposure light, and an absorber pattern, which is a patterned absorber film formed on the multilayer reflective film to absorb the exposure light. In EUV lithography using a reflective mask, the optical image reflected by the multilayer reflective film of the reflective mask is transferred onto a semiconductor substrate (transfer target) such as a silicon wafer through a reflective optical system.

[0004] For example, Patent Document 1 describes a reflective mask blank for manufacturing a reflective mask. Specifically, Patent Document 1 describes a reflective mask blank having a substrate, a multilayer reflective film formed on the substrate and reflecting exposure light, a protective film formed on the multilayer reflective film and protecting the multilayer reflective film, and an absorber film formed on the protective film and absorbing exposure light. Patent Document 1 also describes that the protective film of the reflective mask blank is made of a ruthenium compound containing ruthenium (Ru) and at least one selected from molybdenum (Mo), niobium (Nb), zirconium (Zr), yttrium (Y), boron (B), titanium (Ti), and lanthanum (La).

[0005] The above-mentioned EUV lithography is an exposure technology that uses extreme ultraviolet light (EUV light). EUV light is light in the wavelength band of the soft X-ray region or vacuum ultraviolet region, specifically light with a wavelength of about 0.2 to 100 nm. In the case of EUV lithography, EUV light with a wavelength of 13 to 14 nm (for example, a wavelength of 13.5 nm) can be used.

[0006] A reflective mask having an absorber pattern is used in EUV lithography. EUV light irradiated onto the reflective mask is absorbed in the areas where the absorber pattern is present and reflected in the areas where the absorber pattern is not present. A multilayer reflective film is exposed in the areas where the absorber pattern is not present. The multilayer reflective film exposed on the surface of the reflective mask reflects the EUV light. In EUV lithography, the optical image reflected by the multilayer reflective film (the areas where the absorber pattern is not present) is transferred onto a semiconductor substrate (transfer target) such as a silicon wafer through a reflection optical system.

[0007] Generally, a multilayer reflective film is used in which elements with different refractive indices are periodically stacked. For example, a Mo / Si periodic stacked film is used as a multilayer reflective film for EUV light with a wavelength of 13 to 14 nm (e.g., 13.5 nm), in which Mo films with a low refractive index and Si films with a high refractive index are alternately stacked for 40 to 60 periods.

[0008] In order to achieve high density and high precision in semiconductor devices using a reflective mask, it is necessary for the reflective region of the reflective mask (the surface of the multilayer reflective film) to have high reflectivity with respect to EUV light, which is the exposure light.

[0009] In the manufacturing process of a reflective mask, when an absorber pattern is formed, the absorber film is etched through a resist pattern or an etching mask pattern. To process the absorber film into the designed shape, it is necessary to perform some over-etching on the absorber film. During over-etching, the multilayer reflective film below the absorber film is also damaged by the etching. To prevent the multilayer reflective film from being damaged by the etching, a protective film is provided between the absorber film and the multilayer reflective film. Therefore, the protective film must have high resistance to the etching gas used to etch the absorber film.

[0010] Metals such as Ru or RuNb are used as materials for protective films that have high resistance to the etching gas used to etch the absorber film. On the other hand, if the outermost surface of a multilayer reflective film is a low-refractive index layer such as a Mo film, the low-refractive index layer is easily oxidized. Oxidation of the low-refractive index layer can reduce the reflectivity of the reflective mask. To prevent oxidation of the low-refractive index layer, a silicon-containing layer, such as a Si film, can be disposed on the outermost surface of the multilayer reflective film. Since this silicon-containing layer is a thin film that protects the multilayer reflective film from oxidation, it is treated as part of the protective film in this specification. In this specification, a thin film included in a protective film that protects the multilayer reflective film from oxidation, such as a silicon-containing layer, is referred to as a "first layer." Furthermore, among the above-mentioned protective films, a thin film that has high resistance to the etching gas used to etch the absorber film is referred to as a "second layer." Generally, the first layer is disposed on the multilayer reflective film, and the second layer is disposed on the first layer.

[0011] When the protective film of the multilayer reflective film-coated substrate has a structure in which a second layer containing a metal material is disposed on a first layer (e.g., a Si thin film) on the multilayer reflective film, the multilayer reflective film-coated substrate or the like may be subjected to a heat treatment in the manufacturing process of a reflective mask. The heat treatment of the multilayer reflective film-coated substrate or the reflective mask blank may generally be performed for the purpose of adjusting the stress of the multilayer reflective film-coated substrate or the reflective mask blank.

[0012] As described above, when a structure is provided in which a second layer is disposed on a first layer containing, for example, silicon (Si), a phenomenon may occur in which the reflectivity of the multilayer reflective film-coated substrate for EUV light decreases due to heat treatment or the like in the manufacturing process of a reflective mask. This is thought to be due to the silicon in the first layer diffusing into the second layer. To prevent a decrease in the reflectivity of the multilayer reflective film-coated substrate, it is necessary to prevent the silicon in the first layer from diffusing into the second layer. To prevent the silicon in the first layer from diffusing into the second layer, it is conceivable to nitride and / or oxidize the surface of the first layer (the interface between the first layer and the second layer).

[0013] For example, Patent Document 2 discloses a reflective film-coated substrate for EUV lithography in which a Ru protective layer containing silicon and oxygen is formed on the outermost surface of a silicon-containing multilayer reflective film in order to suppress a decrease in reflectivity of EUV light due to oxidation of the Ru protective film. Also, Patent Documents 3 and 4 disclose reflective film-coated substrates in which a Ru protective layer containing silicon and nitrogen is formed on the outermost surface of a silicon-containing multilayer reflective film.

[0014] Patent Document 1: JP 2005-268750 A, International Publication No. 2011 / 068223, International Publication No. 2011 / 071123, International Publication No. 2023 / 074770

[0015] As described above, there is a problem in that the reflectivity for EUV exposure light is reduced due to interdiffusion of silicon (Si) between the first layer and the second layer on the multilayer reflective film caused by heat treatment or the like when manufacturing a reflective mask from a reflective mask blank. In particular, in recent years, metal oxide film resists considered for high NA (numerical aperture) exposure need to be baked at higher temperatures than currently available, and in addition, light sources are becoming increasingly higher in output as the accuracy of EUV exposure improves. Therefore, there is a demand for reflective masks that can withstand higher temperatures than before, and for reflective mask blanks and the like for manufacturing such masks.

[0016] The interdiffusion of Si in the protective film when a thermal load is applied can be said to depend on the chemical bonding state between Si and the other component (X) at the interface between the first layer and the second layer. The inventors have noticed that the greater the chemical shift of the Si 2p spectrum measured by X-ray photoelectron spectroscopy (XPS), the greater the effect of suppressing thermal diffusion in the protective film, and have newly defined a P value calculated based on this Si 2p spectrum as an index of thermal diffusion suppression.

[0017] The present invention aims to suppress thermal diffusion and maintain reflectivity for EUV light even under high-temperature heat treatment in a multilayer reflective film-coated substrate including a multilayer reflective film and a protective film having a first layer and a second layer containing Si on the multilayer reflective film, by setting the P value calculated based on the Si2p spectrum of the protective film to a range equal to or greater than a predetermined value. Another object of the present invention is to obtain a multilayer reflective film-coated substrate having high heat resistance and maintaining reflectivity for EUV light even under high-temperature heat treatment, by setting the P value calculated based on the Si2p spectrum of the protective film to a range equal to or greater than a predetermined value.

[0018] Another object of the present invention is to obtain a reflective mask blank or a reflective mask having high heat resistance and maintaining reflectivity to EUV light even under high-temperature heat treatment by setting the P value calculated based on the Si2p spectrum of the protective film to a range equal to or greater than a predetermined value.

[0019] In order to solve the above problems, the present invention has the following configuration.

[0020] (Configuration 1) Configuration 1 is a multilayer reflective film coated substrate having a substrate, a multilayer reflective film provided on the substrate, and a protective film provided on the multilayer reflective film, wherein the protective film includes a first layer on the multilayer reflective film and a second layer in contact with the first layer, the first layer and the second layer of the protective film contain silicon (Si), and the P value of the protective film is 1.5 or more and 10.0 or less, and the P value is calculated based on a Si2p spectrum analyzed by X-ray photoelectron spectroscopy, and is given by P=(S ＳｉＸ / S Ｓｉ ) × (u ＳｉＸ -u Ｓｉ ) SiX: Si compound SＳｉ : Area of ​​Si-derived peak in Si2p spectrum S ＳｉＸ : Area of ​​SiX-derived peak in Si2p spectrum u Ｓｉ : Position of Si-derived peak u ＳｉＸ : Position of peak derived from SiX.

[0021] (Configuration 2) Configuration 2 is the multilayer reflective film-coated substrate of configuration 1, wherein the first layer contains silicon (Si) and one or more elements selected from oxygen (O) and nitrogen (N).

[0022] (Configuration 3) Configuration 3 is the multilayer reflective film-coated substrate of configuration 2, wherein the ratio of the content of one or more elements selected from O and N to the content of Si in the first layer is 0.1 or more and 1.5 or less.

[0023] (Configuration 4) Configuration 4 is the multilayer reflective film coated substrate of configuration 1, wherein the second layer contains one or more elements selected from the group consisting of ruthenium (Ru), rhodium (Rh), and iridium (Ir).

[0024] (Structure 5) Structure 5 is the multilayer reflective film-coated substrate of any one of Structures 1 to 4, wherein the second layer contains one or more elements selected from thallium (Tl), hafnium (Hf), titanium (Ti), zirconium (Zr), yttrium (Y), manganese (Mn), indium (In), gallium (Ga), cadmium (Cd), bismuth (Bi), tantalum (Ta), lead (Pb), silver (Ag), aluminum (Al), vanadium (V), niobium (Nb), tin (Sn), zinc (Zn), mercury (Hg), chromium (Cr), iron (Fe), antimony (Sb), tungsten (W), molybdenum (Mo), and copper (Cu).

[0025] (Configuration 6) Configuration 6 is a reflective mask blank comprising the multilayer reflective film coated substrate of any one of configurations 1 to 5, and an absorber film on the protective film.

[0026] (Configuration 7) Configuration 7 is a reflective mask provided with an absorber pattern obtained by patterning the absorber film of the reflective mask blank of configuration 6.

[0027] (Configuration 8) Configuration 8 is a method for manufacturing a semiconductor device, characterized by comprising a step of performing a lithography process using an exposure apparatus with the reflective mask of configuration 7 to form a transfer pattern on a transfer target.

[0028] According to the present invention, a multilayer reflective film-coated substrate including a multilayer reflective film and a first layer and a second layer containing Si thereon can maintain its reflectivity to EUV light even under high-temperature heat treatment and have high heat resistance. Also, the present invention can provide a multilayer reflective film-coated substrate that maintains its reflectivity to EUV light even under high-temperature heat treatment and has high heat resistance.

[0029] Furthermore, the present invention can provide a reflective mask blank or a reflective mask that maintains its reflectivity for EUV light even under high-temperature heat treatment and has high heat resistance.

[0030] FIG. 1 is a cross-sectional view schematically showing an example of a multilayer reflective film coated substrate of the present embodiment. FIG. 2 is a cross-sectional view schematically showing an example of a reflective mask blank of the present embodiment. FIG. 3 is a cross-sectional view schematically showing another example of a reflective mask blank of the present embodiment. FIG. 4 is a view for explaining a method for calculating a P value based on a Si2p spectrum measured in a protective film. FIG. 5 is a view for explaining a method for determining a measurement depth of a Si2p spectrum in a protective film. FIG. 6 is a cross-sectional view schematically showing an example of a method for manufacturing a reflective mask of the present embodiment. FIG. 7 is a cross-sectional view schematically showing a further example of a method for manufacturing a reflective mask of the present embodiment. FIG. 8 is a cross-sectional view schematically showing a further example of a method for manufacturing a reflective mask of the present embodiment. FIG. 9 is a cross-sectional view schematically showing a further example of a method for manufacturing a reflective mask of the present embodiment. FIG. 10 is a cross-sectional view schematically showing an example of an EUV exposure apparatus.

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following embodiments are intended to specifically explain the present invention, and are not intended to limit the scope of the present invention.

[0032] Fig. 1 is a cross-sectional schematic diagram showing an example of a multilayer reflective film-coated substrate 90 of this embodiment. The multilayer reflective film-coated substrate 90 shown in Fig. 1 includes a multilayer reflective film 2 and a protective film 3 on a substrate 1. The protective film 3 includes a first layer 32 and a second layer 34, in this order, on the multilayer reflective film 2. The multilayer reflective film-coated substrate 90 may further include other thin films, such as a back surface conductive film 5.

[0033] Fig. 2 is a cross-sectional schematic diagram showing an example of a reflective mask blank 100 of this embodiment. The reflective mask blank 100 shown in Fig. 2 comprises a multilayer reflective film 2, a protective film 3, and an absorber film 4 on a substrate 1. The reflective mask blank 100 may have a back surface conductive film 5. The multilayer reflective film-coated substrate 90 may further have other thin films such as a resist film 11.

[0034] Fig. 3 is a cross-sectional schematic diagram showing another example of a reflective mask blank 100. The reflective mask blank 100 shown in Fig. 3 further comprises an etching mask film 6 on an absorber film 4 in addition to the configuration shown in Fig. 2. Note that the reflective mask blank 100 may further comprise other thin films such as a resist film 11.

[0035] In this specification, "thin film B is disposed (formed) on thin film A (or substrate)" not only means that thin film B is disposed (formed) in contact with the surface of thin film A (or substrate), but also means that another thin film C is present between thin film A (or substrate) and thin film B. Furthermore, in this specification, for example, "thin film B is disposed in contact with the surface of thin film A (or substrate)" means that thin film A (or substrate) and thin film B are disposed so as to be in direct contact with each other, without any other thin film interposed between them. Furthermore, in this specification, "on" does not necessarily mean the upper side in the vertical direction. "on" merely indicates the relative positional relationship between the thin film, the substrate, etc.

[0036] <Substrate 90 with Multilayer Reflective Film> This embodiment is a substrate 90 with a multilayer reflective film, which includes a substrate 1, a multilayer reflective film 2 provided on the substrate 1, and a protective film 3 provided on the multilayer reflective film 2. The substrate 90 with a multilayer reflective film of this embodiment will be specifically described.

[0037] <<Substrate 1>> The substrate 1 preferably has a low thermal expansion coefficient within the range of 0±5 ppb / °C to prevent distortion of the transferred pattern due to heat during exposure to EUV light. Examples of materials having a low thermal expansion coefficient within this range include SiO ２ -TiO ２ Glasses, multi-component glass ceramics, etc. can be used.

[0038] The main surface (first main surface) of the substrate 1 on which a transfer pattern (the absorber pattern 4a described below) is formed is preferably processed to increase its flatness. Increasing the flatness of the main surface of the substrate 1 can improve the positional accuracy and transfer accuracy of the pattern. For example, in the case of EUV exposure, in a 132 mm × 132 mm area of ​​the main surface of the substrate 1 on which the transfer pattern is formed, the flatness is preferably 0.1 μm or less, more preferably 0.05 μm or less, and particularly preferably 0.03 μm or less. Furthermore, the second main surface (rear surface) opposite the side on which the transfer pattern is formed is the surface fixed to the exposure apparatus by an electrostatic chuck. In a 142 mm × 142 mm area of ​​the rear surface, the flatness is 0.1 μm or less, more preferably 0.05 μm or less, and particularly preferably 0.03 μm or less. In this specification, flatness is a value representing the warpage (deformation amount) of the surface indicated by TIR (Total Indicated Reading). The flatness (TIR) ​​is the absolute value of the difference in height between the highest point on the surface of substrate 1 above the focal plane, which is determined by the least squares method using the surface of substrate 1 as a reference, and the lowest point on the surface of substrate 1 below this focal plane.

[0039] In the case of EUV exposure, the surface roughness of the main surface of the substrate 1 on which the transfer pattern is formed is preferably 0.1 nm or less in terms of root mean square roughness (Rq). The surface roughness can be measured using an atomic force microscope.

[0040] The substrate 1 preferably has high rigidity to prevent deformation due to film stress of the thin films (such as the multilayer reflective film 2) formed thereon. In particular, it is preferable that the substrate 1 has a high Young's modulus of 65 GPa or more.

[0041] <<Multilayer reflective film 2>>

[0042] The multilayer reflective film coated substrate 90 of the embodiment includes a multilayer reflective film 2. The multilayer reflective film 2 provides the reflective mask 200 with the function of reflecting EUV light. The multilayer reflective film 2 is a multilayer film in which layers each containing elements with different refractive indices as main components are periodically stacked.

[0043] Generally, the multilayer reflective film 2 is a multilayer film in which thin films of high refractive index materials, i.e., light elements or compounds thereof (high refractive index layers), and thin films of low refractive index materials, i.e., heavy elements or compounds thereof (low refractive index layers), are alternately stacked in approximately 40 to 60 cycles.

[0044] The multilayer film used as the multilayer reflective film 2 can have a structure in which multiple periods of a high-refractive-index layer / low-refractive-index layer stacked in this order from the substrate 1 side are stacked. Alternatively, the multilayer film can have a structure in which multiple periods of a low-refractive-index layer / high-refractive-index layer stacked in this order from the substrate 1 side are stacked. The topmost layer of the multilayer reflective film 2, i.e., the surface layer of the multilayer reflective film 2 opposite the substrate 1 side, is preferably a high-refractive-index layer. In the above-described multilayer film, when multiple periods of a high-refractive-index layer / low-refractive-index layer stacked in this order from the substrate 1 side are stacked, the topmost layer is the low-refractive-index layer. In this case, if the low-refractive-index layer constitutes the topmost surface of the multilayer reflective film 2, it will be easily oxidized, thereby reducing the reflectivity of the reflective mask 200. Therefore, it is preferable to further form a high-refractive-index layer on the topmost low-refractive-index layer. The high-refractive index layer formed on the uppermost low-refractive index layer can be the first layer 32 of the protective film 3 described below. On the other hand, in the above-mentioned multilayer film, if a low-refractive index layer / high-refractive index layer stack structure in which a low-refractive index layer and a high-refractive index layer are stacked in this order from the substrate 1 side is stacked multiple times, the uppermost layer will be the high-refractive index layer. Therefore, in this case, there is no need to form an additional high-refractive index layer. In this case, the uppermost high-refractive index layer can also serve as the first layer 32 of the protective film 3 described below.

[0045] The high-refractive index layer can be a layer containing silicon (Si). Examples of materials containing Si include elemental Si and Si compounds containing boron (B), carbon (C), nitrogen (N), oxygen (O), and / or hydrogen (H). By using a high-refractive index layer containing Si, a reflective mask 200 with excellent reflectivity for EUV light can be obtained. The low-refractive index layer can be a metal element selected from molybdenum (Mo), ruthenium (Ru), rhodium (Rh), and platinum (Pt), or an alloy thereof. These metal elements or alloys may also be doped with boron (B), carbon (C), nitrogen (N), oxygen (O), and / or hydrogen (H). In the multilayer reflective film-coated substrate 90 of this embodiment, the low-refractive index layer is preferably a molybdenum (Mo) layer, and the high-refractive index layer is preferably a silicon (Si) layer. For example, a Mo / Si periodic stacked film in which Mo layers and Si layers are alternately stacked for approximately 40 to 60 periods can be preferably used as the multilayer reflective film 2 for reflecting EUV light with a wavelength of 13 nm to 14 nm (e.g., 13.5 nm). Furthermore, in the multilayer reflective film-coated substrate 90 of this embodiment, the low refractive index layers are preferably ruthenium (Ru) layers, and the high refractive index layers are preferably silicon (Si) layers. For example, a Ru / Si periodic stacked film in which Ru layers and Si layers are alternately stacked for approximately 30 to 40 periods can be preferably used as the multilayer reflective film 2 for reflecting EUV light with a wavelength of 13 nm to 14 nm (e.g., 13.5 nm).

[0046] The reflectance of the multilayer reflective film 2 alone is usually 65% ​​or more, with the upper limit usually being 73%. The film thickness and period of each constituent layer of the multilayer reflective film 2 can be appropriately selected depending on the exposure wavelength. Specifically, the film thickness and period of each constituent layer of the multilayer reflective film 2 can be selected so as to satisfy the law of Bragg reflection. The multilayer reflective film 2 has a plurality of high refractive index layers and a plurality of low refractive index layers, but the film thicknesses of the high refractive index layers and the low refractive index layers do not necessarily have to be the same.

[0047] Methods for forming the multilayer reflective film 2 are known in the art. The multilayer reflective film 2 can be formed by depositing each layer by, for example, ion beam sputtering. In the case of the Mo / Si periodic multilayer film described above, for example, a Si film having a thickness of about 4 nm is first deposited on the substrate 1 by ion beam sputtering using a Si target, and then a Mo film having a thickness of about 3 nm is deposited using a Mo target. This constitutes one period, and 40 to 60 periods are stacked to form the multilayer reflective film 2 (the outermost layer is a Si film). Note that, although 60 periods requires more steps than 40 periods, the reflectivity for EUV light can be increased.

[0048] <<Protective Film 3>> As shown in FIG. 1 , the multilayer reflective film-coated substrate 90 of this embodiment has a predetermined protective film 3 on the multilayer reflective film 2. When manufacturing the reflective mask 200, the absorber film 4 is etched to form an absorber pattern 4a. The protective film 3 has high etching resistance, and therefore can suppress damage to the surface of the multilayer reflective film 2 when etching the absorber film 4. Therefore, by having the predetermined protective film 3 on the multilayer reflective film 2, damage to the surface of the multilayer reflective film 2 can be suppressed when manufacturing the reflective mask 200 using the multilayer reflective film-coated substrate 90. As a result, the resulting reflective mask 200 has good reflectance characteristics for EUV light.

[0049] In this specification, the predetermined protective film 3 that can be used for the multilayer reflective film coated substrate 90 of this embodiment may be referred to as the "protective film 3 of this embodiment."

[0050] The protective film 3 of this embodiment includes a first layer 32 and a second layer 34. The first layer 32 and the second layer 34 contain silicon (Si). The first layer 32 is disposed between the second layer 34 and the multilayer reflective film 2. The first layer 32 is a thin film that functions to protect the multilayer reflective film 2 from oxidation. In this specification, the first layer 32 is a part of the protective film 3. The first layer 32 can also serve as the top layer of the multilayer reflective film 2. The second layer 34 is a thin film that functions to have high resistance to the etching gas used to etch the absorber film 4. The second layer 34 needs to be a thin film that has high reflectivity for EUV light and high etching resistance to the etching gas used to etch the absorber film 4.

[0051] When the protective film 3 has a structure in which the second layer 34 is disposed on the first layer 32, a phenomenon may occur in which the reflectivity of the multilayer reflective film-coated substrate 90 for EUV light decreases due to heat treatment or the like in the manufacturing process of the reflective mask. This is thought to be due to the diffusion of a predetermined element (an element that exhibits the function of the first layer 32) in the first layer 32 into the second layer 34. In order to prevent a decrease in the reflectivity of the multilayer reflective film-coated substrate 90, it is necessary to prevent the predetermined element in the first layer 32 from diffusing into the second layer 34. In order to prevent the predetermined element in the first layer 32 from diffusing into the second layer 34, it is considered to nitriding and / or oxidizing the surface of the first layer 32 (the interface between the first layer 32 and the second layer 34). On the other hand, it has been found that nitriding and / or oxidizing the surface of the first layer 32 (the interface with the second layer 34) causes a problem of reduced adhesion between the first layer 32 and the second layer 34. If the adhesion between the first layer 32 and the second layer 34 decreases, there is a risk of film peeling defects occurring.

[0052] The protective film 3 of this embodiment contains at least one metal element Em and at least one metal element Ea. That is, the first layer 32 and the second layer 34 constituting the protective film 3 can contain the metal element Em and / or the metal element Ea. By containing the metal element Em, the protective film 3 of this embodiment can have high etching resistance against the etching gas of the absorber film 4. Furthermore, by containing the metal element Ea, the protective film 3 of this embodiment can improve the adhesion between the first layer 32 and the second layer 34. Therefore, the protective film 3 of this embodiment can suppress the occurrence of film peeling defects. That is, the protective film 3 of this embodiment can obtain a multilayer reflective film-coated substrate 90 that can improve the adhesion between the first layer 32 and the second layer 34 while maintaining the high etching resistance of the protective film 3. Furthermore, as will be described later, the protective film 3 of this embodiment can have high heat resistance against high-temperature heat treatment and the like by setting the P value calculated based on the Si 2p spectrum analyzed by X-ray photoelectron spectroscopy (XPS) within a predetermined range.

[0053] <<<Metal Element Em>>> The protective film 3 contains at least one metal element Em. The metal element Em is an element having a Fermi level of −4.7 eV or less. In this specification, the content (atomic %) of the metal element Em is indicated by the symbol “M.” In addition, in this specification, the metal element Em is also referred to as the Em element.

[0054] The metal element Em is an element (metal element) that functions as the protective film 3. The metal element Em has a Fermi level of −4.7 eV or less, and therefore has low reactivity with chlorine (Cl)-based gases, bromine (Br)-based gases, and fluorine (F)-based gases, as well as gases containing nitrogen and / or oxygen as constituent elements that are used in reactive sputtering. Therefore, when the metal element Em is used as the material for the protective film 3, the material is less likely to deteriorate, and the function of the protective film 3 is less likely to be reduced. Therefore, when the metal element Em is selected according to the material of the absorber film 4 disposed on the protective film 3 and the metal element Em is used as the material for the protective film 3, a protective film 3 with high etching resistance can be obtained.

[0055] In this specification, the Fermi level of a certain element refers to the energy value of the Fermi level of a pure substance of the element when the vacuum level is taken as the origin (zero). In this specification, the Fermi level of a metallic material can be the energy obtained by making the value of the work function negative. For example, when the metallic element Em is Ru, the work function of a pure substance of the Ru element (pure substance of Ru metal) is 4.7 eV, and therefore, in this specification, the Fermi level of Ru is −4.7 eV. The same applies to the metallic element Ea described below.

[0056] The metal element Em can be an element having a Fermi level equal to or lower than that of Ru. Ru is known to be a suitable element for forming the protective film 3. Therefore, by using an element (metal element) having a Fermi level equal to or lower than that of Ru (a Fermi level with a large negative value), a thin film having high etching resistance can be obtained.

[0057] Examples of elements having a Fermi level lower than that of Ru include Ru, Tc, Os, Co, Re, Rh, Pd, Au, Ni, Ir, and Pt. At least one selected from these elements can be used as the metal element Em.

[0058] The metal element Em contained in the protective film 3 of this embodiment is preferably one or more elements selected from ruthenium (Ru), rhodium (Rh), and iridium (Ir). The metal element Em contained in the protective film 3 of this embodiment can consist of only one or more elements selected from ruthenium (Ru), rhodium (Rh), and iridium (Ir). By using these elements, it is possible to more reliably obtain a protective film 3 that has high etching resistance while maintaining high reflectivity.

[0059] Specifically, when the protective film 3 contains Rh or Ir as the metal element Em, it is possible to improve the etching resistance of the protective film 3. Furthermore, when the protective film 3 contains Ru as the metal element Em, it is possible to appropriately adjust the optical properties of the protective film 3.

[0060] <<<Metal Element Ea>>> The protective film 3 contains at least one metal element Ea. The metal element Ea is an element having a Fermi level of greater than −4.7 eV. In this specification, the content (atomic %) of the metal element Ea is indicated by the symbol “A.” In addition, in this specification, the metal element Ea is also referred to as the Ea element.

[0061] The inclusion of the metal element Ea in the protective film 3 can improve the adhesion between the first layer 32 and the second layer 34 that constitute the protective film 3. The metal element Ea is an element that has a Fermi level of more than −4.7 eV and is therefore highly reactive with other elements. Therefore, the inclusion of the metal element Ea in the protective film 3 can contribute to improving the adhesion between the first layer 32 and the second layer 34.

[0062] The metal element Ea can be an element having a Fermi level equal to or higher than that of Cu. Cu can be used as an element that can improve the adhesion between two types of thin films. Therefore, using an element having a Fermi level equal to or higher than that of Cu (a Fermi level with a small negative value) can contribute to improving the adhesion between the first layer 32 and the second layer 34.

[0063] The metal element Ea contained in the protective film 3 of this embodiment is preferably one or more elements selected from thallium (Tl), hafnium (Hf), titanium (Ti), zirconium (Zr), yttrium (Y), manganese (Mn), indium (In), gallium (Ga), cadmium (Cd), bismuth (Bi), tantalum (Ta), lead (Pb), silver (Ag), aluminum (Al), vanadium (V), niobium (Nb), tin (Sn), zinc (Zn), mercury (Hg), chromium (Cr), iron (Fe), antimony (Sb), tungsten (W), molybdenum (Mo), and copper (Cu). The metal element Ea contained in the protective film 3 of this embodiment can consist of only one or more elements selected from Tl, Hf, Ti, Zr, Y, Mn, In, Ga, Cd, Bi, Ta, Pb, Ag, Al, V, Nb, Sn, Zn, Hg, Cr, Fe, Sb, W, Mo, and Cu. Use of these elements can more reliably contribute to improving the adhesion between the first layer 32 and the second layer 34.

[0064] The metal element Ea contained in the protective film 3 of this embodiment is more preferably at least one selected from Ti, Zr, Ta, Nb, and Cr. Furthermore, it is even more preferable to use at least one selected from Ta, Nb, and Cr as the metal element Ea contained in the protective film 3 of this embodiment. By using these elements, it is possible to improve the adhesion between the first layer 32 and the second layer 34 and also improve cleaning resistance.

[0065] When nitrogen is contained near the surface of the first layer 32 (the interface between the first layer 32 and the second layer 34), it is more preferable to use Cr as the metal element Ea contained in the protective film 3 of this embodiment. This is because Cr, when nitrided, reduces the extinction coefficient, reduces absorption of EUV light, and can contribute to improving reflectance.

[0066] When oxygen is contained near the surface of the first layer 32 (the interface between the first layer 32 and the second layer 34), it is preferable to use at least one selected from Hf, V, and Cr as the metal element Ea contained in the protective film 3 of this embodiment. This is because Hf, V, and Cr, when oxidized, can reduce the extinction coefficient, mitigate absorption of EUV light, and contribute to improving reflectance.

[0067] The metal element Em can be contained in either the first layer 32 or the second layer 34. Furthermore, the metal element Ea can be contained in either the first layer 32 or the second layer 34. That is, as long as the metal element Em or Ea can be present at the interface between the first layer 32 and the second layer 34, the metal element Em or Ea can be added when the first layer 32 is formed, or the metal element Em or Ea can be added when the second layer 34 is formed. Furthermore, the metal element Em or Ea can be added when both the first layer 32 and the second layer 34 are formed.

[0068] <<<First Layer 32>>> The first layer 32 of the protective film 3 of this embodiment can be disposed on the multilayer reflective film 2 in contact with the multilayer reflective film 2. The first layer 32 is a thin film that is part of the protective film 3 and protects the multilayer reflective film 2 from oxidation. The first layer 32 of this embodiment contains silicon (Si) and one or more elements selected from oxygen (O) and nitrogen (N).

[0069] More specifically, examples of materials for the first layer 32 include materials containing silicon (Si) (e.g., Si, SiN, SiO, SiON, SiC, SiOC, SiNC, and SiONC). The first layer 32 can be, for example, a thin film formed under conditions such that it is composed only of silicon (Si) or a thin film formed under conditions such that it is composed only of SiN. When the top layer of the multilayer reflective film 2 is a high-refractive index layer, the top high-refractive index layer can also serve as the first layer 32 of the protective film 3. The first layer 32 can also be a compositionally graded film or a laminated film composed of multiple thin layers.

[0070] In the first layer 32 herein, the terms "a thin film formed under conditions such that the film is composed only of silicon (Si)" or "a thin film formed under conditions such that the film is composed only of SiN" refer to a thin film formed under conditions such that the film is composed only of silicon (Si) or a thin film formed under conditions such that the film is composed only of SiN. After the first layer 32 (and the second layer 34 described below) is formed, elements other than those constituting the first layer 32 may diffuse from the nearby multilayer reflective coating 2 and second layer 34 into the first layer 32. In such a case, for example, the first layer 32, which is a "thin film formed under conditions such that the film is composed only of silicon (Si)," will contain elements other than silicon (Si) that diffuse from other layers after the first layer 32 is formed. In this way, elements of other thin films diffuse from a thin film near the first layer 32 into the first layer 32, so that a thin film formed under conditions that consist of only a predetermined element generally contains elements other than the predetermined element. Therefore, a thin film formed under conditions that consist of only silicon (Si) can be a thin film containing Si. Also, a thin film formed under conditions that consist of only SiN can be a thin film containing SiN.

[0071] The first layer 32 of the protective film 3 of this embodiment can be formed by various known methods, such as ion beam sputtering, sputtering, reactive sputtering, chemical vapor deposition (CVD), and vacuum deposition.

[0072] When the first layer 32 is a thin film formed under conditions that allow the first layer 32 to consist only of silicon (Si), the first layer 32 can be formed under conditions that allow the first layer 32 to consist only of silicon (Si). For example, the first layer 32 can be formed by ion beam sputtering using a Si target.

[0073] When the first layer 32 is a thin film formed under conditions in which it consists only of SiN, for example, the first layer 32 can be formed by DC magnetron sputtering (reactive sputtering) using a Si target in a nitrogen gas atmosphere.

[0074] The first layer 32 can be a thin film formed under conditions that allow the first layer 32 to contain the metal element Ea. The first layer 32 can be a thin film that contains Si and the metal element Ea. The first layer 32 can contain the metal element Ea. By including the metal element Ea in the first layer 32, the metal element Ea can be present at the interface between the first layer 32 and the second layer 34. As a result, the adhesion between the first layer 32 and the second layer 34 can be improved.

[0075] The first layer 32 may be a thin film containing Si and the metal element Ea, and may further contain at least one selected from nitrogen (N) and oxygen (O). The first layer 32 preferably contains nitrogen (N) and / or oxygen (O) near the interface with the second layer 34. When the first layer 32 has a high content of nitrogen (N) and / or oxygen (O), it is possible to suppress the diffusion of elements (e.g., silicon (Si)) from the first layer 32 into the second layer 34. As a result, it is possible to suppress a decrease in the reflectivity of the second layer 34 due to the diffusion of elements from the first layer 32.

[0076] In order to introduce nitrogen (N) and / or oxygen (O) into the first layer 32 or the second layer 34, the first layer 32 or the second layer 34 can be formed in a nitrogen gas and / or oxygen gas atmosphere by DC magnetron sputtering (reactive sputtering). As a result, a decrease in the reflectivity of the second layer 34 due to diffusion of elements in the first layer 32 can be suppressed.

[0077] As described above, in order to prevent the elements of the first layer 32 from diffusing into the second layer 34, it is preferable to introduce nitrogen (N) and / or oxygen (O) into the interface between the first layer 32 and the second layer 34 to increase the concentration of nitrogen (N) and / or oxygen (O) at the interface between the first layer 32 and the second layer 34. However, if the concentration of nitrogen (N) and / or the concentration of oxygen (O) at the interface between the first layer 32 and the second layer 34 becomes too high, the reflectivity decreases and the adhesion deteriorates, so it is necessary to set the concentration to a predetermined value.

[0078] The depth position (D ｍ ), the ratio (O / Si) of the oxygen (O) content to the silicon (Si) content in the first layer 32 is preferably 0.6 or more, more preferably 0.8 or more. The ratio (O / Si) is preferably 1.5 or less, more preferably 1.0 or less. The ratio (N / Si) of the nitrogen (N) content to the silicon (Si) content in the first layer 32 is preferably 0.1 or more, more preferably 0.2 or more. The ratio (N / Si) is preferably 0.9 or less, more preferably 0.7 or less. The P value, which will be described later, depends on the chemical bonding state between Si and other components, so the ratios (N / Si) and / or (O / Si) are not necessarily proportional to the P value.

[0079] <<<Second Layer 34>>> The second layer 34 of the protective film 3 of this embodiment is disposed on and in contact with the first layer 32. The second layer 34 can be a thin film that has the same function as the protective film 3, that is, increases the resistance of the protective film 3 to etching gases and cleaning.

[0080] The second layer 34 contains the above-mentioned metal element Em. The second layer 34 can be a thin film formed under conditions that allow the second layer 34 to contain the metal element Em. The content of the metal element Em in the second layer 34 is greater than the content of the metal element Em in the first layer 32. This is because the second layer 34 is required to be a thin film having high etching resistance.

[0081] The second layer 34 can be a thin film formed under conditions that allow it to contain the metal element Em and the metal element Ea. The second layer 34 can contain both the metal element Em and the metal element Ea. The content of the metal element Em in the second layer 34 can be greater than the content of the metal element Ea. By including the metal element Em in the second layer 34, it is possible to obtain a second layer 34 with high etching resistance. Furthermore, by including the metal element Ea in the second layer 34, it is possible to more reliably improve the adhesion between the first layer 32 and the second layer 34.

[0082] The second layer 34 can be a laminated film of two or more layers. The lower layer in contact with the first layer 32 can be a thin film formed under conditions that include the metal element Ea. The lower layer of the second layer 34 can include the metal element Ea. By including the metal element Ea in the lower layer of the second layer 34, the metal element Ea can be present at the interface between the first layer 32 and the second layer 34. As a result, the adhesion between the first layer 32 and the second layer 34 can be improved. More preferably, the metal element Ea included in the lower layer of the second layer 34 is at least one selected from Ti, Zr, Ta, Nb, and Cr. Furthermore, from the viewpoint of adhesion, it is preferable that the lower layer of the second layer 34 does not include the metal element Em, and it is even more preferable that it does not include Ru.

[0083] Furthermore, the upper layer of the second layer 34 on the side in contact with the absorber film 4 can be a thin film formed under conditions that include the metal element Em. The upper layer of the second layer 34 can include the metal element Em. By including the metal element Em in the upper layer of the second layer 34, it becomes possible for the metal element Em to be present at the interface between the second layer 34 and the absorber film 4. As a result, the etching resistance of the absorber film 4 can be increased.

[0084] The second layer 34 can be a compositionally graded film having a gradient composition. The second layer 34 can have a higher content of the metal element Ea than the content of the metal element Em on the side in contact with the first layer 32, and a higher content of the metal element Em than the content of the metal element Ea on the side in contact with the absorber film 4. Furthermore, the second layer 34 can have an increased content of the metal element Ea and a decreased content of the metal element Em in the film thickness direction from the absorber film 4 side toward the first layer 32 side.

[0085] In the second layer 34 herein, the terms "a thin film formed under conditions to contain the metal element Em" or "a thin film formed under conditions to contain the metal element Ea" refer to a thin film formed under conditions to form a thin film containing the metal element Em or a thin film formed under conditions to form a thin film containing the metal element Ea during the formation of the first layer 32. After the formation of the second layer 34, elements other than those constituting the second layer 34 may diffuse from the first layer 32 to the second layer 34. In such a case, for example, the "thin film formed under conditions to contain the metal element Em" will include an element (e.g., silicon (Si)) that diffuses from the first layer 32 to the second layer 34 after the formation of the first layer 32. In this way, a thin film formed under conditions to contain a predetermined element generally contains elements other than the predetermined element due to the diffusion of elements from other thin films from a thin film near the second layer 34 to the second layer 34.

[0086] The second layer 34 preferably contains one or more elements selected from ruthenium (Ru), rhodium (Rh), and iridium (Ir) as the metal element Em. By using these elements, the second layer 34 can be obtained that has high etching resistance and high heat resistance while maintaining high reflectivity.

[0087] The content of the metal element Em in the second layer 34 is preferably 40 to 95 atomic %, and more preferably 50 to 90 atomic %. The content of the metal element Ea in the second layer 34 is preferably 1 to 10 atomic %, and more preferably 2 to 8 atomic %. Note that the above-mentioned contents are those at the position where the total content (atomic %) of the Em element and the Ea element is at its maximum, and can also be said to be the central composition in the thickness direction of the second layer 34.

[0088] The second layer 34 may further contain at least one selected from nitrogen (N) and oxygen (O). The second layer 34 may be a thin film formed under conditions such that it contains the metal element Em, the metal element Ea, and at least one selected from nitrogen (N) and oxygen (O). The second layer 34 may be a thin film formed under conditions such that it contains only at least one selected from the metal element Em, the metal element Ea, nitrogen (N), and oxygen (O).

[0089] In order for the second layer 34 to have high reflectivity for EUV light, the nitrogen (N) and / or oxygen (O) content of the second layer 34 is preferably low. On the other hand, if the nitrogen (N) and / or oxygen (O) content is high, the elements of the first layer 32 (e.g., silicon (Si)) can be suppressed from diffusing into the second layer 34. By suppressing the diffusion of the elements of the first layer 32 (e.g., silicon (Si)) into the second layer 34, it is possible to suppress a decrease in the effective film thickness of the second layer 34, which functions as the protective film 3. In consideration of the above, it is preferable that the second layer 34 contains nitrogen (N) and / or oxygen (O) near the interface with the first layer 32. This can suppress a decrease in the reflectivity of the multilayer reflective coating 2 for EUV light, which would be caused by the diffusion of the elements of the first layer 32 into the second layer 34.

[0090] The total thickness of the first layer 32 and the second layer 34 of the protective film 3 (sometimes simply referred to as the "thickness of the protective film 3") is not particularly limited as long as it can function as the protective film 3. From the viewpoint of reflectivity of EUV light, the thickness of the protective film 3 can be 3.5 nm or more, and can be 6.0 nm or more. The thickness of the protective film 3 can be 8.0 nm or less, and can be 7.0 nm or less.

[0091] The second layer 34 of the protective film 3 of this embodiment can be formed by various known methods, such as ion beam sputtering, sputtering, reactive sputtering, chemical vapor deposition (CVD), and vacuum deposition. The second layer 34 of the protective film 3 of this embodiment is preferably formed by magnetron sputtering (reactive sputtering) in a nitrogen gas atmosphere. The target may be, for example, a single metal target or an alloy target of the metal components (metal elements, e.g., metal element Em and / or metal element Ea) contained in the second layer 34. When the second layer 34 is formed by reactive sputtering, the second layer 34 can be formed continuously in a nitrogen gas atmosphere after the formation of the first layer 32.

[0092] When the second layer 34 is a thin film formed under conditions that include the metal element Em, the metal element Ea, and nitrogen (N) and / or oxygen (O), the second layer 34 can be formed, for example, by DC magnetron sputtering (reactive sputtering) in a nitrogen (N) gas and / or oxygen (O) gas atmosphere using an alloy target of at least one metal element Em and at least one metal element Ea.

[0093] When depositing the second layer 34, the second layer 34 can be deposited with a predetermined composition distribution by changing deposition conditions such as the nitrogen gas flow rate (pressure) and / or applied power. However, if appropriate deposition conditions are selected, the second layer 34 can be deposited with a predetermined composition distribution due to the diffusion of elements within the second layer 34, even when the deposition conditions are kept constant. For example, when obtaining a second layer 34 containing silicon (Si), even if the second layer 34 is deposited under conditions that do not include silicon (Si), the second layer 34 can be obtained after deposition due to the diffusion of silicon (Si) from the first layer 32.

[0094] <<<Si2P Spectral Analysis in Protective Film 3>> As described above, when the protective film 3 has a structure in which a first layer (e.g., a Si thin film) 32 is disposed on the multilayer reflective film 2 and a second layer 34 containing a metal material is disposed on the first layer 32, a phenomenon may occur in which Si in the protective film 3 is mutually diffused by heat treatment in the manufacturing process of the reflective mask 200, resulting in a decrease in the reflectivity of the protective film 3 for EUV light. In particular, metal oxide film resists that have been considered for use in recent high NA exposures need to be baked at higher temperatures than currently available, and higher heat resistance is also required due to the increasing power of exposure light sources.

[0095] It can be said that the interdiffusion of Si when a thermal load is applied depends on the chemical bonding state (chemical shift) between Si and other components (e.g., O, N, C, or a combination of these elements) at the interface between the first layer 32 and the second layer 34. Therefore, the inventors defined the P value, calculated based on the Si 2p spectrum analyzed by X-ray photoelectron spectroscopy (XPS), as an index of thermal diffusion suppression by the following equation 1: SiX: Si (silicon) compound S Ｓｉ : Area of ​​Si-derived peak in Si2p spectrum S ＳｉＸ : Area of ​​SiX-derived peak in Si2p spectrum u Ｓｉ : Position of Si-derived peak u ＳｉＸ : Position of SiX-derived peak

[0096] As shown in the above formula, the P value is the area ratio of the SiX-derived peak to the Si-derived peak analyzed in the Si2p spectrum (S ＳｉＸ / S Ｓｉ ) to the peak shift amount (u ＳｉＸ -u Ｓｉ ) The method for calculating the P value will be specifically described with reference to Fig. 4. Fig. 4 shows an example of a Si 2p spectrum measured near the interface between the first layer 32 and the second layer 34 of the protective layer 3 containing Si.

[0097] In the Si2p spectrum shown in Fig. 4, a peak derived from Si (silicon) and a peak derived from SiX (silicon compound) are observed. Assuming that each peak follows a Gaussian distribution, a fitting curve of the following Equation 2 can be obtained based on the measured Si2p spectrum.

[0098] When fitting the actual measured values ​​(CPS) by X-ray photoelectron spectroscopy to a Gaussian function, a known regression method such as the least squares method can be used.

[0099] Area S of the Si-derived peak in the Si2p spectrum Ｓｉ and the area S of the SiX-derived peak ＳｉＸ can be calculated from the following equation 3 using the coefficients of the fitted Gaussian function:

[0100] In this embodiment, in order to measure the Si 2p spectrum near the interface between the first layer 32 and the second layer 34 of the protective film 3, the measurement depth for the protective film 3 was determined based on the depth profile analysis illustrated in FIG. 5. Specifically, in the composition profile of the composition amount (or composition ratio) in the depth direction as illustrated in FIG. 5, the Si amount was determined to be the first peak value (C Ｓｉ　ｐｅａｋ ) is measured. ｍ ) can be determined as

[0101] The P value calculated as described above is preferably 1.5 or more, more preferably 2.0 or more, and even more preferably 3.0 or more. The P value is also preferably 10.0 or less, more preferably 7.0 or less, and even more preferably 4.0 or less. The reason for this is that if the P value is too high, the proportion of SiX (silicon compound) in the protective film 3 increases, resulting in a decrease in reflectance for EUV light.

[0102] In the protective film 3 of this embodiment, the P value calculated based on the Si2p spectrum is set to a predetermined range, so that a multilayer reflective film-coated substrate 90 having higher heat resistance than conventional substrates can be obtained without causing a decrease in reflectivity for EUV light even under high-temperature heat treatment.

[0103] In the measurement by the XPS method, the measurement may be performed in the state of a reflective mask blank having the absorber film 4 on the protective film 3, or the absorber film 4 and the etching mask film 6, or in the state of a reflective mask after patterning the absorber film 4, to obtain a composition profile in the depth direction of the protective film 3. Even in this case, the P value can be calculated without being affected by the thin film on the protective film 3.

[0104] Furthermore, the P value can be set within a predetermined range by performing a film formation process for the first layer 32 and / or the second layer 34 by reactive sputtering in a gas atmosphere containing O, N, and / or C, an oxidation process and / or a nitriding process on the surface of the first layer 32, an annealing process for the first layer 32 and / or the second layer 34, the conditions for the annealing process (vacuum, air, nitrogen gas, oxygen gas, or other atmosphere, temperature), or a combination of these processes.

[0105] In the multilayer reflective film coated substrate 90 of this embodiment, after the protective film 3 is formed, or after the absorber film 4 is formed to obtain the reflective mask blank 100, a heat treatment can be performed to adjust the stress of thin films such as the protective film 3. In this heat treatment, heating can be performed at a temperature higher than the pre-bake temperature (about 110°C) of the resist film 11 in the manufacturing process of the reflective mask blank 100. Specifically, the temperature condition for the heat treatment can be 150°C or higher, and can be 220°C or higher. In addition, the temperature condition for the heat treatment can be 300°C or lower, and can be 270°C or lower.

[0106] <<Back Surface Conductive Film 5>> The multilayer reflective film-coated substrate 90 of this embodiment can have a back surface conductive film 5 for electrostatic chucks. The back surface conductive film 5 can be formed on the second main surface (backside main surface) of the substrate 1 (opposite the surface on which the multilayer reflective film 2 is formed, and on the intermediate layer if an intermediate layer such as a hydrogen penetration suppression film is formed on the substrate 1). The sheet resistance required for the back surface conductive film 5 for electrostatic chucks is typically 100 Ω / □ (Ω / square) or less. The back surface conductive film 5 can be formed by, for example, magnetron sputtering or ion beam sputtering using a target of a metal such as chromium or tantalum, or an alloy thereof. The chromium (Cr)-containing material of the back surface conductive film 5 is preferably a Cr compound containing Cr and at least one element selected from boron, nitrogen, oxygen, and carbon. Examples of Cr compounds include CrN, CrON, CrCN, CrCON, CrBN, CrBON, CrBCN, and CrBOCN. The tantalum (Ta)-containing material of the backside conductive film 5 is preferably Ta (tantalum), a Ta-containing alloy, or a Ta compound containing at least one of 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. The thickness of the back surface conductive film 5 is not particularly limited as long as it satisfies the function of the electrostatic chuck, but is usually 10 nm to 200 nm. The back surface conductive film 5 also serves to adjust the stress on the second main surface side of the mask blank 100. That is, the back surface conductive film 5 is adjusted to achieve a balance with the stress from the various films formed on the first main surface side, so as to obtain a flat reflective mask blank 100.

[0107] It should be noted that the multilayer reflective film coated substrate 90 does not necessarily need to include the rear surface conductive film 5. For example, the rear surface conductive film 5 can be formed on the reflective mask blank 100 after forming the absorber film 4 described below.

[0108] <Reflective Mask Blank 100> The following describes the reflective mask blank 100 of this embodiment. As shown in Figure 2, the reflective mask blank 100 of this embodiment has an absorber film 4 on the protective film 3 of the multilayer reflective film coated substrate 90 described above.

[0109] <<Absorber Film 4>> The absorber film 4 of the reflective mask blank 100 of this embodiment is formed on the protective film 3. The basic function of the absorber film 4 is to absorb EUV light. The absorber film 4 may be an absorber film 4 intended for absorbing EUV light, or an absorber film 4 having a phase shift function that also takes into account the phase difference of EUV light. An absorber film 4 having a phase shift function absorbs EUV light and reflects a portion of it to shift the phase. That is, in a reflective mask 200 patterned with an absorber film 4 having a phase shift function, the portion where the absorber film 4 is formed absorbs and attenuates EUV light while reflecting a portion of the light at a level that does not adversely affect pattern transfer. Furthermore, in regions (field portions) where the absorber film 4 is not formed, the EUV light is reflected from the multilayer reflective film 2 via the protective film 3. Therefore, a desired phase difference is achieved between the light reflected from the absorber film 4 having a phase shift function and the light reflected from the field portion. The absorber film 4 having a phase shift function is formed so that the phase difference between the reflected light from the absorber film 4 and the reflected light from the multilayer reflective film 2 is 170 to 260 degrees. The lights with the inverted phase difference interfere with each other at the pattern edge, improving the image contrast of the projected optical image. As the image contrast improves, the resolution increases, and various exposure latitudes such as exposure dose latitude and focus latitude can be increased.

[0110] The absorber film 4 may be a single-layer film, or may be a multi-layer film consisting of multiple films (for example, a lower-layer absorber film (buffer layer) and an upper-layer absorber film). A single-layer film has the advantage of reducing the number of steps in mask blank manufacturing, thereby improving production efficiency. In the case of a multi-layer film, the optical constants and film thickness of the upper-layer absorber film can be appropriately set so that it serves as an anti-reflection film during optical mask pattern defect inspection. This improves inspection sensitivity during optical mask pattern defect inspection. Furthermore, using a film to which oxygen (O) or nitrogen (N), which improves oxidation resistance, is added as the upper-layer absorber film improves stability over time. In this way, various functions can be added by making the absorber film 4 a multi-layer film. When the absorber film 4 has a phase shift function, making it a multi-layer film can widen the range of optical adjustment, making it easier to obtain a desired reflectance.

[0111] The material of the absorber film 4 is not particularly limited as long as it has the function of absorbing EUV light, can be processed by etching or the like (preferably can be etched by dry etching with a chlorine (Cl)-based gas and / or a fluorine (F)-based gas), and has a high etching selectivity relative to the protective film 3 (second layer 34). As a material having such a function, at least one metal selected from 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), an alloy containing two or more metals, or a compound thereof can be preferably used. The compound may contain oxygen (O), nitrogen (N), carbon (C), and / or boron (B) in addition to the above metal or alloy.

[0112] The absorber film 4 can be formed by magnetron sputtering such as DC sputtering or RF sputtering. For example, the absorber film 4 made of a tantalum compound or the like can be formed by reactive sputtering using a target containing tantalum and boron and argon gas to which oxygen or nitrogen has been added.

[0113] Furthermore, in terms of smoothness and flatness, the crystalline state of the absorber film 4 is preferably an amorphous or microcrystalline structure. If the surface of the absorber film 4 is not smooth and flat, the edge roughness of the absorber pattern 4 a increases, which may result in poor dimensional accuracy of the pattern. The surface roughness of the absorber film 4 is preferably 0.5 nm or less, more preferably 0.4 nm or less, and even more preferably 0.3 nm or less, in root mean square roughness (Rms).

[0114] In this embodiment, a reflective mask blank 100 having a structure in which a protective film 3 made of a material containing a metal is placed on a high refractive index layer can be obtained, which can suppress a decrease in the reflectivity of the multilayer reflective film 2 against EUV light even when heat treatment is performed on the reflective mask blank 100.

[0115] 3 , the reflective mask blank 100 of this embodiment can have an etching mask film 6 on the absorber film 4. As a material for the etching mask film 6, it is preferable to use a material that has a high etching selectivity of the absorber film 4 to the etching mask film 6 (etching rate of the absorber film 4 / etching rate of the etching mask film 6). The etching selectivity of the absorber film 4 to the etching mask film 6 is preferably 1.5 or more, and more preferably 3 or more.

[0116] The reflective mask blank 100 of this embodiment preferably has an etching mask film 6 on the absorber film 4 .

[0117] Chromium or a chromium compound is preferably used as the material for the etching mask film 6. Examples of chromium compounds include materials containing Cr and at least one element selected from N, O, C, and H. The etching mask film 6 more preferably contains CrN, CrO, CrC, CrON, CrOC, CrCN, or CrOCN, and further preferably is a CrO-based film containing chromium and oxygen (a CrO film, a CrON film, a CrOC film, or a CrOCN film).

[0118] Tantalum or a tantalum compound is preferably used as the material of the etching mask film 6. Examples of tantalum compounds include a material containing Ta and at least one element selected from N, O, B, and H. More preferably, the etching mask film 6 contains TaN, TaO, TaON, TaBN, TaBO, or TaBON.

[0119] Silicon or a silicon compound is preferably used as the material for the etching mask film 6. Examples of silicon compounds include a material containing Si and at least one element selected from N, O, C, and H, as well as metal silicon (metal silicide) and metal silicon compounds (metal silicide compounds) containing a metal in silicon or a silicon compound. Examples of metal silicon compounds include a material containing a metal, Si, and at least one element selected from N, O, C, and H.

[0120] The thickness of the etching mask film 6 is preferably 3 nm or more in order to form a pattern with high precision in the absorber film 4. Moreover, the thickness of the etching mask film 6 is preferably 15 nm or less in order to make the thickness of the resist film 11 thin.

[0121] <Reflective Mask 200> This embodiment is a reflective mask 200 having an absorber pattern 4a obtained by patterning the absorber film 4 of the above-described reflective mask blank.

[0122] As shown in FIG. 6D, the reflective mask 200 of this embodiment includes an absorber pattern 4 a obtained by patterning the absorber film 4 of the above-mentioned reflective mask blank 100 .

[0123] 6A to 6D are schematic diagrams showing an example of a method for manufacturing a reflective mask 200. The reflective mask blank 100 of this embodiment described above can be used to manufacture the reflective mask 200 of this embodiment. An example of the method for manufacturing the reflective mask 200 will be described below.

[0124] First, a reflective mask blank 100 is prepared, which includes a substrate 1, a multilayer reflective film 2 formed on the substrate 1, a protective film 3 formed on the multilayer reflective film 2, and an absorber film 4 formed on the protective film 3. Next, a resist film 11 is formed on the absorber film 4 to obtain a reflective mask blank 100 with the resist film 11 (FIG. 6A). A pattern is written on the resist film 11 using an electron beam lithography device, and a developing and rinsing process is then performed to form a resist pattern 11a (FIG. 6B).

[0125] Using the resist pattern 11a as a mask, the absorber film 4 is dry-etched, whereby the portions of the absorber film 4 that are not covered by the resist pattern 11a are etched, and an absorber pattern 4a is formed (FIG. 6C).

[0126] As an etching gas for the absorber film 4, for example, a fluorine-based gas and / or a chlorine-based gas can be used. As the fluorine-based gas, CF ４ , CHF ３ , C ２ F ６ , C ３ F ６ , C ４ F ６ , C ４ F ８ , C.H. ２ F ２ , C.H. ３ F, C ３ F ８ , SF ６ , and F ２ The chlorine-based gas may be Cl ２ , SiCl ４ , CHCl ３ , CCl ４ , and BCl ３ In addition, a fluorine-based gas and / or a chlorine-based gas and O ２In this case, a mixed gas containing a predetermined ratio of these may be used. These etching gases may further contain an inert gas such as He and / or Ar, if necessary.

[0127] After the absorber pattern 4a is formed, the resist pattern 11a is removed with a resist remover solution. After the resist pattern 11a is removed, a wet cleaning process using an acidic or alkaline aqueous solution is performed, thereby obtaining the reflective mask 200 of this embodiment (FIG. 6D).

[0128] In addition, when a reflective mask blank 100 in which an etching mask film 6 is formed on an absorber film 4 is used, an additional process is performed in which a pattern (etching mask pattern) is formed on the etching mask film 6 using the resist pattern 11a as a mask, and then a pattern is formed on the absorber film 4 using the etching mask pattern as a mask.

[0129] The reflective mask 200 thus obtained has a structure in which a multilayer reflective film 2, a protective film 3, and an absorber pattern 4a are laminated on a substrate 1.

[0130] The exposed region (reflective region) of the multilayer reflective film 2 covered with the protective film 3 has the function of reflecting EUV light. The region where the multilayer reflective film 2 and the protective film 3 are covered with the absorber pattern 4 a has the function of absorbing EUV light. The reflective mask 200 of this embodiment can suppress a decrease in the reflectivity of the reflective region for EUV light even when subjected to heat treatment. By using the reflective mask 200 of this embodiment, a reflective region that maintains high reflectivity for EUV light can be obtained, making it possible to transfer finer patterns onto a transfer target in EUV lithography.

[0131] In the reflective mask 200 of this embodiment, the adhesion at the interface between the first layer 32 and the second layer 34 of the protective film 3 can be improved. Therefore, the occurrence of film peeling defects in the reflective mask 200 of this embodiment can be suppressed. Furthermore, in the reflective mask 200 of this embodiment, the adhesion at the interface between the first layer 32 and the second layer 34 of the protective film 3 can be improved, high reflectivity for EUV light can be maintained, and high heat resistance of the protective film 3 can be achieved. Therefore, the reflective mask 200 of this embodiment can be used for manufacturing high-performance semiconductor devices.

[0132] <Method for Manufacturing Semiconductor Device> The method for manufacturing a semiconductor device according to this embodiment includes a step of performing a lithography process using an exposure apparatus and the above-described reflective mask 200 to form a transfer pattern on a transfer target.

[0133] A transfer pattern can be formed on a semiconductor substrate 60 (transfer receiving body) by lithography using the reflective mask 200 of this embodiment. This transfer pattern has a shape that is the result of transferring the pattern of the reflective mask 200. By forming a transfer pattern on the semiconductor substrate 60 using the reflective mask 200, a semiconductor device can be manufactured.

[0134] According to this embodiment, a semiconductor device can be manufactured using a multilayer reflective film coated substrate 90 that can suppress a decrease in the reflectivity of the multilayer reflective film 2 for EUV light even when heat treatment is performed, and a reflective mask 200 made from a reflective mask blank 100. Therefore, by using the reflective mask 200 of this embodiment, it is possible to manufacture semiconductor devices with higher density and precision.

[0135] A method for transferring a pattern onto a semiconductor substrate 60 with a resist by using EUV light will be described with reference to FIG.

[0136] 7 shows a schematic configuration of an EUV exposure apparatus 50, which is an apparatus for transferring a transfer pattern onto a resist film 11 formed on a semiconductor substrate 60. The EUV exposure apparatus 50 includes an EUV light generation unit 51, an irradiation optical system 56, a reticle stage 58, a projection optical system 57, and a wafer stage 59, which are precisely arranged along the optical path axis of the EUV light. The container of the EUV exposure apparatus 50 is filled with hydrogen gas.

[0137] The EUV light generation unit 51 has a laser light source 52, a tin droplet generation unit 53, a capture unit 54, and a collector 55. When the high-power carbon dioxide laser from the laser light source 52 irradiates the tin droplets emitted from the tin droplet generation unit 53, the tin droplets are converted into plasma, and EUV light is generated. The generated EUV light is collected by the collector 55 and passes through an irradiation optical system 56 to be incident on a reflective mask 200 set on a reticle stage 58. The EUV light generation unit 51 generates EUV light with a wavelength of, for example, 13.53 nm.

[0138] The EUV light reflected by the reflective mask 200 is reduced by the projection optical system 57 to a pattern image light, typically about one-fourth the original size, and projected onto the semiconductor substrate 60 (transferred substrate). As a result, a given circuit pattern is transferred onto a resist film on the semiconductor substrate 60. A resist pattern can be formed on the semiconductor substrate 60 by developing the exposed resist film. An integrated circuit pattern can be formed on the semiconductor substrate 60 by etching the semiconductor substrate 60 using the resist pattern as a mask. A semiconductor device is manufactured through these and other necessary processes.

[0139] Examples 1 to 11 are described below. Examples 1 to 4 and 8 to 11 are working examples, and Examples 5 to 7 are comparative examples. These examples do not limit the present invention.

[0140] As Examples 1 to 11, a multilayer reflective film coated substrate 90 was produced in which a multilayer reflective film 2 and a protective film 3 were formed on the first main surface of a substrate 1 .

[0141] The multilayer reflective film coated substrates 90 of Examples 1 to 11 were fabricated as follows.

[0142] A SiO 6025 size (approximately 152 mm x 152 mm x 6.35 mm) low thermal expansion glass substrate 1 with both the first and second main surfaces polished. ２ -TiO ２ A glass substrate 1 was prepared as the substrate 1. To obtain a flat and smooth main surface, polishing was carried out through a rough polishing process, a precision polishing process, a local polishing process, and a touch polishing process.

[0143] Next, a multilayer reflective film 2 was formed on the first main surface of the substrate 1. The multilayer reflective film 2 was a periodic multilayer reflective film 2 made of Si and Mo to be suitable for EUV light with a wavelength of 13.5 nm. Specifically, a Si target and a Mo target were used as the high-refractive index material target and the low-refractive index material target. Krypton (Kr) ion particles were supplied from an ion source to these targets to perform ion beam sputtering, thereby alternately laminating Si layers and Mo layers on the substrate 1.

[0144] Here, the Si and Mo sputtered particles were incident at an angle of 30 degrees with respect to the normal to the first main surface of the substrate 1. First, a Si layer was formed to a thickness of 4.2 nm, followed by a Mo layer to a thickness of 2.8 nm. This constitutes one cycle, and 40 cycles were stacked in the same manner. Therefore, the material of the bottom layer of the multilayer reflective film 2, i.e., the material of the multilayer reflective film 2 closest to the substrate 1, was Si, and the material of the top layer of the multilayer reflective film 2 was Mo.

[0145] Next, a protective film 3 consisting of a first layer 32 and a second layer 34 was formed on the multilayer reflective film 2 of Examples 1 to 11.

[0146] First, a first layer 32 of the protective film 3 was formed on the surface of the multilayer reflective film 2. The first layer 32 was formed under the same conditions as those used in the method for forming the Si layer of the multilayer reflective film 2. At this time, the first layer 32 was formed so that the set film thickness of the first layer 32 was 4.0 nm, based on the relationship between the film formation rate and film formation time of the Si layer under predetermined conditions.

[0147] In Examples 1 to 3 and 11, after the first layer 32 was formed, N ２In Examples 4 and 10, after the first layer 32 was formed, the oxide layer formed on the surface of the first layer 32 was removed by plasma irradiation in an Ar gas-containing atmosphere. ２ The annealing treatment was carried out while irradiating plasma in an atmosphere containing N ２ In Example 7, the annealing treatment was performed in the air. In Examples 8 and 9, after the first layer 32 was formed, the annealing treatment was performed in the atmosphere of a mixed gas of O and Ar gas. ２ Annealing was performed under plasma irradiation in a gas-containing atmosphere. Table 1 shows the annealing temperature and time.

[0148] Next, a second layer 34 was formed on the surface of the first layer 32. Table 2 shows the continuity of the film formation process between the formation of the first layer 32 and the formation of the second layer 34. In Table 2, the term "continuous" indicates that after the formation of the first layer 32, the sample was not taken out into the atmosphere, and the second layer 34 was continuously formed in the film formation apparatus. In Table 2, the term "discontinuous" indicates that after the formation of the first layer 32, the sample was taken out into the atmosphere, and then the sample was placed in the film formation apparatus to form the second layer 34.

[0149] The second layers 34 of Examples 1 to 4 and 6 to 11 were used for sintered targets having the compositions shown in Table 2, and the N ２ Gas and / or Ar gas flow rate ratio N ２The films were deposited to the set film thicknesses shown in Table 2 by DC magnetron sputtering (reactive sputtering) in a gas atmosphere introduced with Cr / Ar (flow rate unit: sccm: Standard Cubic Centimeter per Minute). The second layer 34 of Example 4 was a two-layer film with a lower layer being a Cr film and an upper layer being a Rh film. The second layer 34 of Example 10 was a two-layer film with a lower layer being a Zr film and an upper layer being a RhZr film. The upper RhZr film was deposited using an Rh target and a Zr target. The second layer 34 of Example 10 had an increased Zr content in the film thickness direction from the absorber film 4 side toward the first layer 32 side. The second layer 34 of Example 11 was a two-layer film with a lower layer being a Ti film and an upper layer being a Rh film. The second layer 34 in Example 5 was formed to the set film thickness shown in Table 2 by ion beam sputtering using a Ru target and supplying argon (Ar) ion particles from an ion source. In Examples 4, 7, 10, and 11, the second layer 34 was formed and then annealed under the conditions shown in Table 2.

[0150] (Measurement of P Value) Next, the protective films 3 (first layer 32 and second layer 34) of Examples 1 to 11 were measured by X-ray photoelectron spectroscopy (XPS). In this measurement, the surface of the protective film 3 was irradiated with X-rays (AlKα rays: 1486 eV) to measure the intensity of photoelectrons emitted from the protective film 3, the surface of the protective film 3 was excavated for a predetermined time (to a depth of about 0.7 nm) by Ar gas sputtering, the excavated region of the protective film 3 was irradiated with X-rays to measure the intensity of photoelectrons emitted from the excavated region of the protective film 3, and these steps were repeated to obtain composition profiles in the depth direction of the protective films 3 of Examples 1 to 11. Next, in the composition profiles in the depth direction of the protective films 3 of Examples 1 to 11, the amount of Si was measured at a first peak value C Ｓｉ　ｐｅａｋ Depth D indicates 1 / 2 of ｍ The Si2p spectrum was extracted at a depth D. The extracted Si2p spectrum was subjected to the above-mentioned fitting using a Gaussian function. The P value was calculated from the parameters obtained by the fitting based on the above-mentioned formula 1. The results are shown in Table 3. In addition, in the composition profiles in the depth direction of the protective film 3 of Examples 1 to 11, ｍThe ratios of the N content and the O content to the Si content (N / Si and O / Si) were calculated. The results are shown in Table 3.

[0151] (Evaluation of multilayer reflective film coated substrate 90) Using the multilayer reflective film coated substrates 90 of Examples 1 to 11 produced under the same film formation conditions as above, changes in reflectance of the multilayer reflective film coated substrates 90 due to heat treatment were measured. Specifically, first, the reflectance (R1, unit: %) of the multilayer reflective film coated substrates 90 of Examples 1 to 11 to EUV light (wavelength: 13.5 nm) was measured. Next, the multilayer reflective film coated substrates 90 were placed in a vacuum (1.0×10 －４ The multilayer reflective film-coated substrate 90 was subjected to a heat treatment by heating at 250°C for 10 minutes in a pressure of 10 Pa. After the heat treatment of the multilayer reflective film-coated substrate 90, the reflectivity (R2, unit: %) of the multilayer reflective film-coated substrate 90 to EUV light was measured. The change in EUV reflectivity of the multilayer reflective film-coated substrate 90 due to the heat treatment was obtained by subtracting the value of the reflectivity (R2) of the multilayer reflective film-coated substrate 90 after the heat treatment from the value of the reflectivity (R1) of the multilayer reflective film-coated substrate 90 before the heat treatment. However, for Example 7, the reflectivity (R1) before the heat treatment was low, and the required reflectivity for the multilayer reflective film-coated substrate 90 could not be obtained, so the heat treatment was not performed. Table 3 shows the measurement results of the change in reflectivity (%) to EUV light of the multilayer reflective film-coated substrates 90 of Examples 1 to 6 and 8 to 11.

[0152] From the above, in the multilayer reflective film-coated substrates 90 of Examples 1 to 4 and 8 to 11, by setting the P value to 1.5 or more and 10.0 or less, high reflectivity for EUV light could be maintained after heat treatment. However, in the multilayer reflective film-coated substrates 90 of Examples 8 and 9, although the change in reflectivity was small, the reflectivity (R1) before heat treatment was lower than in Examples 1 to 4, 10, and 11. Furthermore, in the multilayer reflective film-coated substrates 90 of Examples 5 and 6, the P value was less than 1.5, and therefore the reflectivity for EUV light decreased after heat treatment.

[0153]

[0154]

[0155]

[0156] REFERENCE SIGNS LIST 1 substrate 2 multilayer reflective film 3 protective film 4 absorber film 4a absorber pattern 5 back surface conductive film 6 etching mask film 11 resist film 11a resist pattern 32 first layer 34 second layer 50 EUV exposure apparatus 51 EUV light generation unit 52 laser light source 53 tin droplet generation unit 54 capture unit 55 collector 56 irradiation optical system 57 projection optical system 58 reticle stage 59 wafer stage 60 semiconductor substrate 90 substrate with multilayer reflective film 100 reflective mask blank 200 reflective mask

Claims

1. A substrate with a multilayer reflective film, comprising a substrate, a multilayer reflective film provided on the substrate, and a protective film provided on the multilayer reflective film, wherein the protective film includes a first layer on the multilayer reflective film and a second layer in contact with the first layer, the first layer and the second layer of the protective film contain silicon (Si), the P value of the protective film is 1.5 or more and 10.0 or less, the P value is calculated based on the Si2p spectrum analyzed by X-ray photoelectron spectroscopy, and P = (S ＳｉＸ / S Ｓｉ ) × (u ＳｉＸ - u Ｓｉ ) where SiX: a compound of Si, S Ｓｉ : the area of the Si-derived peak in the Si2p spectrum, S ＳｉＸ : the area of the SiX-derived peak in the Si2p spectrum, u Ｓｉ : the position of the Si-derived peak, u ＳｉＸ : the position of the SiX-derived peak, and is defined as a substrate with a multilayer reflective film.

2. The substrate with a multilayer reflective film according to claim 1, wherein the first layer contains silicon (Si) and one or more elements selected from oxygen (O) and nitrogen (N).

3. The substrate with a multilayer reflective film according to claim 2, wherein the ratio of the content of one or more elements selected from O and N to the content of Si in the first layer is 0.1 or more and 1.5 or less.

4. The substrate with a multilayer reflective film according to claim 1, wherein the second layer contains one or more elements selected from ruthenium (Ru), rhodium (Rh), and iridium (Ir).

5. The substrate with a multilayer reflective film according to any one of claims 1 to 4, wherein the second layer contains one or more elements selected from thallium (Tl), hafnium (Hf), titanium (Ti), zirconium (Zr), yttrium (Y), manganese (Mn), indium (In), gallium (Ga), cadmium (Cd), bismuth (Bi), tantalum (Ta), lead (Pb), silver (Ag), aluminum (Al), vanadium (V), niobium (Nb), tin (Sn), zinc (Zn), mercury (Hg), chromium (Cr), iron (Fe), antimony (Sb), tungsten (W), molybdenum (Mo), and copper (Cu).

6. A reflective mask blank having a substrate, a multilayer reflective film provided on the substrate, a protective film provided on the multilayer reflective film, and an absorber film provided on the protective film, wherein the protective film includes a first layer on the multilayer reflective film and a second layer in contact with the first layer, the first layer and the second layer of the protective film contain silicon (Si), the P value of the protective film is 1.5 or more and 10.0 or less, the P value is calculated based on the Si2p spectrum analyzed by X-ray photoelectron spectroscopy, P = (S ＳｉＸ / S Ｓｉ ) × (u ＳｉＸ −u Ｓｉ ) SiX: A compound of Si S Ｓｉ : The area of the Si-derived peak in the Si2p spectrum S ＳｉＸ : The area of the SiX-derived peak in the Si2p spectrum u Ｓｉ : The position of the Si-derived peak u ＳｉＸ : The position of the SiX-derived peak, which is a reflective mask blank defined thereby.

7. The reflective mask blank according to claim 6, wherein the first layer contains silicon (Si) and one or more elements selected from oxygen (O) and nitrogen (N).

8. The reflective mask blank according to claim 7, wherein the ratio of the content of one or more elements selected from O and N to the content of Si in the first layer is 0.1 or more and 1.5 or less.

9. The reflective mask blank according to claim 6, wherein the second layer contains one or more elements selected from ruthenium (Ru), rhodium (Rh), and iridium (Ir).

10. The reflective mask blank according to any one of claims 6 to 9, wherein the second layer contains one or more elements selected from thallium (Tl), hafnium (Hf), titanium (Ti), zirconium (Zr), yttrium (Y), manganese (Mn), indium (In), gallium (Ga), cadmium (Cd), bismuth (Bi), tantalum (Ta), lead (Pb), silver (Ag), aluminum (Al), vanadium (V), niobium (Nb), tin (Sn), zinc (Zn), mercury (Hg), chromium (Cr), iron (Fe), antimony (Sb), tungsten (W), molybdenum (Mo), and copper (Cu).

11. A reflective mask having a substrate, a multilayer reflective film provided on the substrate, a protective film provided on the multilayer reflective film, and an absorber pattern provided on the protective film, wherein the protective film includes a first layer on the multilayer reflective film and a second layer in contact with the first layer, the first layer and the second layer of the protective film contain silicon (Si), the P value of the protective film is 1.5 or more and 10.0 or less, the P value is calculated based on the Si2p spectrum analyzed by X-ray photoelectron spectroscopy, P = (S ＳｉＸ / S Ｓｉ ) × (u ＳｉＸ −u Ｓｉ ) SiX: A compound of Si S Ｓｉ : The area of the Si-derived peak in the Si2p spectrum S ＳｉＸ : The area of the SiX-derived peak in the Si2p spectrum u Ｓｉ : The position of the Si-derived peak u ＳｉＸ : The position of the SiX-derived peak, a reflective mask defined thereby.

12. The reflective mask according to claim 11, wherein the first layer contains silicon (Si) and one or more elements selected from oxygen (O) and nitrogen (N).

13. The reflective mask according to claim 12, wherein the ratio of the content of one or more elements selected from O and N to the content of Si in the first layer is 0.1 or more and 1.5 or less.

14. The reflective mask according to claim 11, wherein the second layer contains one or more elements selected from ruthenium (Ru), rhodium (Rh), and iridium (Ir).

15. The reflective mask according to any one of claims 11 to 14, wherein the second layer contains one or more elements selected from thallium (Tl), hafnium (Hf), titanium (Ti), zirconium (Zr), yttrium (Y), manganese (Mn), indium (In), gallium (Ga), cadmium (Cd), bismuth (Bi), tantalum (Ta), lead (Pb), silver (Ag), aluminum (Al), vanadium (V), niobium (Nb), tin (Sn), zinc (Zn), mercury (Hg), chromium (Cr), iron (Fe), antimony (Sb), tungsten (W), molybdenum (Mo), and copper (Cu).

16. A method for manufacturing a semiconductor device, comprising the step of performing a lithography process using an exposure apparatus and forming a transfer pattern on a transfer object, using the reflective mask according to any one of claims 11 to 15.

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