Conductive film-equipped substrate, multilayer reflective film-equipped substrate, mask blank, reflective mask, and method for manufacturing semiconductor device

Abstract

Provided is a conductive film-equipped substrate in which damage received by a conductive film due to etching of an absorber film or the like is small even when a hard-to-etch material is used for the absorber film or the like.　The conductive film-equipped substrate is provided with: a substrate having a first main surface and a second main surface facing the first main surface; a first film formed on the first main surface and having a first film composition; and a conductive film formed on the second main surface and having a second film composition. In a first etching condition used for etching the first film, the etching selection ratio of the first film composition to the second film composition is not less than 0.8 or is less than 0.

Description

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

[0001] The present disclosure relates to a substrate with a conductive film, a substrate with a multilayer reflective film, a mask blank, a reflective mask, and a method for manufacturing a semiconductor device.

[0002] In general, in the manufacturing process of semiconductor devices, fine patterns are formed using photolithography. Furthermore, to form these fine patterns, a number of transfer masks, also known as photomasks, are typically used. These transfer masks are generally formed by providing a fine pattern made of a metal thin film or the like on a glass substrate. Electron beam lithography is used to manufacture these transfer masks.

[0003] In the manufacture of a transfer mask using electron beam lithography, a mask blank is used, which has a thin film (e.g., a light-shielding film) for forming a transfer pattern (mask pattern) on a substrate such as a glass substrate. The manufacture of a transfer mask using this mask blank involves a writing process, a development process, an etching process, and a resist pattern removal process. In the writing process, a desired pattern is written on a resist film formed on the mask blank. In the development process, after writing, the resist film is developed to form a desired resist pattern. In the etching process, the thin film is etched using the resist pattern as a mask. In the resist pattern removal process, the remaining resist pattern is removed. More specifically, in the development process, a developer is supplied to the resist film after the writing process to dissolve the resist film in areas soluble in the developer, thereby forming a resist pattern. In the etching process, the resist pattern is used as a mask to remove exposed thin film where no resist pattern is formed by dry etching or wet etching. This forms a desired mask pattern on the substrate. In this way, a transfer mask is completed.

[0004] Known types of transfer masks include a binary mask having a light-shielding film pattern made of a chromium-based material on a conventional substrate, and a phase-shift mask.

[0005] Furthermore, in recent years, with the increasing integration density of semiconductor devices in the semiconductor industry, there has been a demand for finer patterns that exceed the transfer limit of conventional lithography methods using ultraviolet light. To enable the formation of such fine patterns, there is EUV lithography, an exposure technology using extreme ultraviolet (EUV) light. Hereinafter, extreme ultraviolet light will be referred to as EUV light. Hereinafter, EUV light refers to light in the wavelength band of the soft X-ray region or the vacuum ultraviolet region, more specifically, light with a wavelength of approximately 0.2 to 100 nm. In this disclosure, EUV light refers to light including light with a wavelength of 13.5 nm, specifically light with a wavelength of 13 to 14 nm, more specifically light with a wavelength of 13.5 nm. In this disclosure, light includes not only visible light but also electromagnetic waves. A reflective mask is used in this EUV lithography. Such a reflective mask has a substrate, a multilayer reflective film, and an absorber film. The multilayer reflective film is formed on the substrate and reflects EUV light, which is exposure light, and the absorber film is formed in a pattern on the multilayer reflective film and absorbs EUV light.

[0006] A reflective mask is supported by an electrostatic chuck in an exposure apparatus during pattern transfer onto a semiconductor substrate, for example. Meanwhile, the substrate used in a reflective mask blank or a reflective mask is made of an insulating glass substrate or the like. Therefore, a conductive film (rear conductive film) is formed on the rear surface of the substrate of a reflective mask blank or a reflective mask. As a conventional technique, for example, Patent Document 1 discloses a mask substrate having a rear coating (conductive film) made of a material with a higher dielectric constant than the substrate, such as silicon, molybdenum, chromium, chromium oxynitride, or TaSi. Patent Document 2 also discloses an absorber film made of a material that is difficult to etch.

[0007] JP 2003-501823 A, WO 2023 / 171582

[0008] In recent years, in order to improve pattern resolution and throughput and / or reduce the so-called shadowing effect, there has been a demand for absorber films made of materials with a high refractive index and a low extinction coefficient for EUV light. However, as disclosed in the above-mentioned Patent Document 2, such materials are so-called difficult to etch and therefore have a low etching rate. Furthermore, the use of difficult-to-etch materials has also been increasing for protective films formed between multilayer reflective films and absorber films. Therefore, etching such difficult-to-etch materials requires a longer etching time than conventional materials.

[0009] The conductive film is formed on the second main surface (backside) of the substrate, opposite the first main surface on which the absorber film is formed. Therefore, when etching the absorber film, the conductive film is almost completely shielded. Therefore, even if the gas used to etch the absorber film finds its way to the backside, the conductive film is not significantly damaged by the etching if the absorber film is made of a conventional material. However, the inventors' investigations have revealed that when the absorber film (or an etching mask film, protective film, etc. on the absorber film) is made of a material that is difficult to etch, even if the conductive film is almost completely shielded, the etching gas that finds its way to the backside can damage the conductive film (especially near the periphery). Damage to the conductive film can also affect the substrate chucking force of the electrostatic chuck, the quality of the reflective mask, and / or the pattern transfer accuracy.

[0010] The present disclosure has been made in consideration of these problems, and its object is, first, to provide a substrate with a conductive film in which the conductive film is less damaged by etching of the absorber film, etc., even when a material that is difficult to etch is used for the absorber film, etc. Also, its object is, second, to provide a multilayer reflective film-coated substrate, a mask blank, and a reflective mask that use the above-mentioned substrate with a conductive film, and third, to provide a method for manufacturing a semiconductor device that uses this reflective mask.

[0011] The present inventors have pursued intensive research to solve the problems of the prior art, and as a result have completed the following invention: (Configuration 1) A substrate with a conductive film, comprising: a substrate having a first main surface and a second main surface opposite the first main surface; a first film formed on the first main surface and having a first film composition; and a conductive film formed on the second main surface and having a second film composition, wherein, under first etching conditions used to etch the first film, an etching selectivity of the first film composition to the second film composition is 0.8 or more or less than 0.

[0012] (Configuration 2) A substrate with a conductive film, comprising: a substrate having a first main surface and a second main surface opposite the first main surface; a first film formed on the first main surface; and a conductive film formed on the second main surface and having a second film, wherein, under first etching conditions used to etch the first film, an etching selectivity of the first film to the second film is 0.8 or more or less than 0.

[0013] (Structure 3) The substrate with a conductive film according to Structure 1 or 2, wherein, when the first film is etched under the first etching conditions, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the first film is 20% or less of the film thickness at the outer periphery of the conductive film before etching of the first film. (Structure 4) The substrate with a conductive film according to any of Structures 1 to 3, wherein an etching rate of the first film under the first etching conditions is greater than 0 and 0.5 nm / sec or less.

[0014] (Structure 5) The substrate with a conductive film according to any one of Structures 1 to 4, wherein the conductive film is a single-layer film. (Structure 6) The substrate with a conductive film according to any one of Structures 1, 3, or 4, wherein the conductive film has an upper layer farthest from the second main surface of the substrate and a lower layer formed between the upper layer and the second main surface, the upper layer having the second film composition. (Structure 7) The substrate with a conductive film according to any one of Structures 2 to 4, wherein the conductive film has an upper layer farthest from the second main surface of the substrate and a lower layer formed between the upper layer and the second main surface, the upper layer being the second film.

[0015] (Configuration 8) The substrate with a conductive film according to any one of configurations 1 to 7, wherein the conductive film contains at least one of hafnium, niobium, ruthenium, iridium, and rhodium.

[0016] (Structure 9) A substrate with a multilayer reflective film, comprising, on the first main surface of the substrate with a conductive film described in any one of Structures 1 to 8, a multilayer reflective film including alternatingly stacked high refractive index layers and low refractive index layers, or a protective film formed on the multilayer reflective film and the multilayer reflective film, wherein the first film is the multilayer reflective film or the protective film.

[0017] (Structure 10) A mask blank comprising a multilayer reflective film including alternating high refractive index layers and low refractive index layers on the first main surface of the conductive film-coated substrate according to any one of Structures 1 to 8, and the first film formed on the multilayer reflective film.

[0018] (Structure 11) The mask blank according to Structure 10, further comprising an absorber film that absorbs EUV light on the multilayer reflective film, or an etching mask film provided on the absorber film and the absorber film, and the first film is the absorber film or the etching mask film.

[0019] (Structure 12) A reflective mask comprising a multilayer reflective film including alternating high refractive index layers and low refractive index layers on the first main surface of a substrate with a conductive film described in any one of Structures 1 to 8, wherein the first film is formed on the multilayer reflective film and has a transfer pattern.

[0020] (Structure 13) The reflective mask according to structure 12, further comprising an absorber film that absorbs EUV light on the multilayer reflective film, the first film being the absorber film.

[0021] (Configuration 14) A method for manufacturing a semiconductor device, comprising the step of transferring the transfer pattern onto a transfer target by exposure using the reflective mask according to configuration 12 or 13.

[0022] According to the present disclosure, it is possible to provide a substrate with a conductive film in which the conductive film is less damaged by etching of the absorber film, etc., even when a material that is difficult to etch is used for the absorber film, etc. Furthermore, according to the present disclosure, it is possible to provide a multilayer reflective film-coated substrate, a mask blank, and a reflective mask using the above-mentioned substrate with a conductive film. A reflective mask manufactured from a mask blank using the above-mentioned substrate with a conductive film suffers less damage to the conductive film, and therefore does not affect the substrate chucking force by an electrostatic chuck, the quality of the reflective mask, or the pattern transfer accuracy.

[0023] Furthermore, the present disclosure provides a method for manufacturing a semiconductor device using this reflective mask. By performing pattern transfer using this reflective mask that causes less damage to the conductive film, a good substrate adsorption force can be obtained by the electrostatic chuck, and therefore, high-precision pattern transfer can be performed without causing transfer position deviation during exposure.

[0024] Fig. 1 is a cross-sectional view showing a substrate with a conductive film according to an embodiment of the present disclosure; Fig. 2 is a cross-sectional view showing a substrate with a multilayer reflective film according to an embodiment of the present disclosure; Fig. 3 is a cross-sectional view showing a reflective mask blank according to an embodiment of the present disclosure; Fig. 4 is a cross-sectional view showing a reflective mask blank according to another embodiment of the present disclosure; Fig. 5 is a cross-sectional view showing a reflective mask according to an embodiment of the present disclosure; Fig. 6 is a cross-sectional view showing a substrate with a conductive film according to another embodiment of the present disclosure.

[0025] Embodiments of the present disclosure will be described in detail below. [Substrate with Conductive Film] First, the substrate with conductive film of the present disclosure will be described. The substrate with conductive film of the present disclosure comprises a substrate having a first main surface and a second main surface opposite the first main surface, a first film formed on the first main surface and having a first film composition, and a conductive film formed on the second main surface and having a second film composition. Under first etching conditions used to etch the first film, the etching selectivity of the first film composition relative to the second film composition is 0.8 or more or less than 0. The conductive film also includes a second film having the second film composition. Therefore, the etching selectivity of the first film relative to the second film is 0.8 or more or less than 0. Here, the etching selectivity of the film (film composition) X1 to the film (film composition) X2 is the value ER(X1) / ER(X2) obtained by dividing the etching rate ER(X1) of the film (film composition) X1 under the first etching conditions by the etching rate ER(X2) of the film (film composition) X2 under the first etching conditions.

[0026] FIG. 1 is a cross-sectional view showing a conductive film-coated substrate according to an embodiment of the present disclosure. As shown in FIG. 1 , a conductive film-coated substrate 10 according to this embodiment includes a substrate 1 having a first main surface 1t (the upper surface of the substrate 1 in FIG. 1 ) and a second main surface 1b (the lower surface of the substrate 1 in FIG. 1 ) opposite the first main surface 1t, a first film 7 formed on the first main surface 1t and having a first film composition, and a conductive film 2 formed on the second main surface 1b and having a second film composition (second film). The lower surface is also referred to as the back surface. A multilayer reflective film-coated substrate 20 (described below) is a type of conductive film-coated substrate 10 because it includes a conductive film 2 on the second main surface 1b of the substrate 1. Furthermore, a mask blank (reflective mask blanks 30, 40, and 50) and a reflective mask 60 (described below) are both types of conductive film-coated substrate 10 because they also include a conductive film 2 on the second main surface 1b of the substrate 1.

[0027] The substrate 1 has two opposing main surfaces (the first main surface 1t and the second main surface 1b) and four end faces. When the conductive film-coated substrate of the present disclosure is used, for example, in a reflective mask blank for EUV exposure, a glass substrate is preferred as the substrate 1. In particular, to prevent distortion of the pattern due to heat during exposure, the substrate 1 is preferably a glass substrate having a thickness of 0±1.0×10 －７ / °C, more preferably 0±0.3×10 －７ A glass substrate having a low thermal expansion coefficient within the range of 1 / °C is used. 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.

[0028] The main surface (first main surface) 1t of the glass substrate 1 on which the transfer pattern is formed is surface-processed to have a high degree of flatness in order to improve at least the pattern transfer accuracy and positional accuracy. In the case of EUV exposure, the flatness in a 142 mm × 142 mm area of ​​the first main surface 1t on which the transfer pattern of the glass substrate 1 is formed is preferably 0.1 μm or less, and particularly preferably 0.05 μm or less. In the present disclosure, flatness is a value representing the surface warpage (deformation amount) indicated by TIR (Total Indicated Reading). This value is the absolute value of the difference in height between the highest position on the surface of the substrate 1 above the focal plane, which is defined by the least squares method with the surface of the substrate 1 as the focal plane, and the lowest position on the surface of the substrate 1 below the focal plane.

[0029] In the case of EUV exposure, the glass substrate 1 is made of SiO ２ -TiO ２ Materials having a low thermal expansion coefficient, such as silicon-based glass, are preferably used. For the purpose of reducing the surface roughness of the glass substrate 1 or reducing defects on the surface of the glass substrate 1, an underlayer may be formed on the first main surface 1t of the glass substrate 1 on which the transfer pattern is to be formed, as necessary. The material for such an underlayer does not need to be transparent to the exposure light, and is preferably selected from materials that provide high smoothness and good defect quality when the underlayer surface is precision polished. For example, Si or a silicon compound containing Si (e.g., SiO ２ Silicon nitride (SiON, SiON, etc.) provides high smoothness and good defect quality when precision polished. For this reason, the above-mentioned Si or silicon compounds containing Si are preferably used as the material for the underlayer. Si is particularly preferred as the material for the underlayer. By using such an underlayer, it is possible to achieve high smoothness, for example, a root-mean-square roughness (Rq) of 0.1 nm or less as the surface roughness of the glass substrate 1.

[0030] The surface of the underlayer is preferably precision-polished to achieve the smoothness required for a reflective mask blank substrate. The surface of the underlayer is desirably precision-polished to a root-mean-square roughness (Rq) of 0.15 nm or less, particularly preferably 0.1 nm or less. Furthermore, taking into consideration the influence on the surface of the multilayer reflective film formed on the underlayer, the surface of the underlayer is precision-polished so that the relationship between the root-mean-square roughness (Rq) and the maximum height (Rmax) is preferably Rmax / Rq of 2 to 10, particularly preferably 2 to 8. The film thickness of the underlayer is preferably in the range of, for example, 10 nm to 300 nm.

[0031] The first film 7 is formed on the first main surface it of the substrate 1 and has a first film composition. This first film 7 may be any film that is to be patterned. This first film 7 may be, for example, an absorber film in a reflective mask blank described below, or an etching mask film provided on the absorber film. Furthermore, when an etching stopper film to be patterned is provided, the first film 7 may be the etching stopper film.

[0032] Furthermore, in a multilayer reflective film-coated substrate including a multilayer reflective film including alternating high-refractive index layers and low-refractive index layers on the first main surface 1t of the conductive film-coated substrate, or the multilayer reflective film and a protective film formed thereon, the first film 7 can be a multilayer reflective film or a protective film. For example, to form a black border of a reflective mask, the multilayer reflective film, or the multilayer reflective film and the protective film, may be etched to form a pattern corresponding to the black border. In such cases, the effects of the present disclosure can be effectively achieved. The black border here refers to a region provided on the periphery of an area including a transfer pattern of the reflective mask so that the transfer pattern is exposed. The black border is formed to prevent exposure light from leaking into an area adjacent to the transfer area on the semiconductor substrate where the pattern is transferred during pattern transfer using a reflective mask.

[0033] The material of the first film 7 is not particularly limited as long as it does not impair the effects of the present disclosure. Examples of the material of the first film 7 include a material containing at least one element selected from ruthenium (Ru), rhodium (Rh), tantalum (Ta), chromium (Cr), molybdenum (Mo), niobium (Nb), titanium (Ti), zirconium (Zr), yttrium (Y), silicon (Si), palladium (Pd), silver (Ag), platinum (Pt), gold (Au), iridium (Ir), tungsten (W), cobalt (Co), manganese (Mn), tin (Sn), vanadium (V), nickel (Ni), iron (Fe), hafnium (Hf), copper (Cu), tellurium (Te), zinc (Zn), magnesium (Mg), germanium (Ge), osmium (Os), and aluminum (Al). In addition to these elements, the material of the first film 7 may further contain at least one element selected from oxygen (O), nitrogen (N), carbon (C), boron (B), hydrogen (H), and noble gases. In particular, when a material that is difficult to etch among these materials is used as the material of the first film 7, the effects of the present disclosure are more effectively exhibited. Examples of the material that is difficult to etch include rhodium (Rh), platinum (Pt), iridium (Ir), and palladium (Pd).

[0034] Furthermore, the conductive film 2 is formed on the second major surface 1b of the substrate 1 and has a second film composition (second film). The conductive film 2 may be a single-layer film or a laminated film. The laminated film has an upper layer farthest from the substrate 1 and a lower layer formed between the upper layer and the second major surface 1b of the substrate 1. When the conductive film 2 is a laminated film including such an upper layer and a lower layer, it is preferable that at least the upper layer has the second film composition. That is, the upper layer can be the second film. The conductive film 2 may have an intermediate layer between the upper layer and the lower layer. The intermediate layer can be a single layer or multiple layers. The lower layer and the intermediate layer may be collectively referred to as the lower layer. Hereinafter, when the term "lower layer" is used simply, unless otherwise specified, it includes a configuration in which the lower layer and the intermediate layer are collectively referred to as the lower layer. That is, the lower layer can include multiple layers. In the present disclosure, when the conductive film 2 is a laminated film, it is sufficient that the etching selectivity of the first film 7 having the first film composition relative to the layer (upper layer) of the conductive film 2 as the second film that is farthest from the substrate 1 is 0.8 or more or less than 0.

[0035] On the other hand, in the present disclosure, when the conductive film 2 is a laminated film, the etching selectivity of the first film 7 relative to at least the intermediate layer of the conductive film 2 or a layer (e.g., a lower layer) in contact with the second main surface 1b of the substrate 1 may be 0.8 or more or less than 0. That is, the intermediate layer of the conductive film 2 or the layer (e.g., a lower layer) in contact with the second main surface 1b of the substrate 1 may be the second film. Substrates with a conductive film (including substrates with a conductive film, substrates with a multilayer reflective film, mask blanks, and reflective masks) are typically inspected after manufacture. In this inspection, light of a specific wavelength is irradiated onto the second main surface 1b of the substrate 1 on which the conductive film 2 is formed, and the reflected light from the conductive film 2 is detected to determine the quality of the substrate. If the outer periphery of the second main surface 1b of the substrate 1 is exposed due to damage to the conductive film 2 caused by etching the first film 7, sufficient reflected light cannot be obtained from the outer periphery during the inspection. As a result, a substrate with a conductive film whose outer periphery of the second main surface 1b is exposed may be determined to be defective. Since the intermediate layer of the conductive film 2 or the layer in contact with the second main surface 1b of the substrate 1 (e.g., the lower layer) is the second film, even if the upper layer of the conductive film 2 is damaged by etching the first film 7, exposure of the outer periphery of the second main surface 1b of the substrate 1 can be suppressed or reduced.

[0036] When the conductive film 2 includes an upper layer and a lower layer, the upper layer may be formed to protect the lower layer during etching of the first film 7. In this case, the upper layer may be removed, if necessary, after etching of the first film 7. When removing the upper layer, it is preferable that the upper layer be easily removable using a cleaning solution or the like. When removing the upper layer by cleaning, the upper layer can be removed using, for example, SPM (sulfuric acid-hydrogen peroxide mixture) cleaning using an aqueous solution of sulfuric acid and hydrogen peroxide, or SC1 (Standard Clean 1) cleaning using ammonia-hydrogen peroxide mixture (aqueous solution of ammonia water and hydrogen peroxide water). The upper layer does not necessarily have to be removed.

[0037] When the upper layer of the conductive film 2 is a second film having a second film composition, in order to suppress or reduce damage to the conductive film 2 near its periphery due to etching of the first film 7, it is preferable that the upper layer (second film) having the second film composition covers at least the side surfaces of the lower layer, more preferably the periphery of the lower layer, and particularly preferably the entire surface of the lower layer so as to prevent the lower layer from being exposed. To form an upper layer (second film) so that it covers at least the side surfaces or the periphery of the lower layer, the following steps may be performed. First, a lower layer is formed on the second main surface 1b of the substrate 1. Then, an upper layer is formed while shielding the areas other than the side surfaces or the periphery of the lower layer so that only the side surfaces or the periphery of the lower layer are exposed.

[0038] The film provided on the substrate 1, including the lower layer of the conductive film 2, has a shape in which the film thickness gradually decreases in the region near the edge of the film as it approaches the edge in a cross-sectional view. That is, the side surface of the lower layer is not necessarily perpendicular to the surface of the substrate 1 in a cross-sectional view. Therefore, in the present disclosure, the side surface of the lower layer can be, for example, the region from the point where the film thickness begins to decrease toward the edge of the lower layer to the edge in a cross-sectional view. When the length L is the distance between two opposing edges of the lower layer in a top view, the outer periphery of the lower layer can extend, for example, from one edge of the lower layer to the other opposing edge within a range of 0.5% or less, preferably 0.8% or less, and more preferably 1% or less of the length L. When the main surfaces 1t and 1b of the substrate 1 are rectangular, the length L may be the distance between the two opposing long sides of the lower layer in a top view. More specifically, the outer periphery of the lower layer can extend from one edge of the lower layer to the other opposing edge within 2.0 mm. Conductive film 2, including the lower layer, is often formed to extend to the edge of second main surface 1b of substrate 1. For this reason, the outer periphery of the lower layer may extend, for example, within 2.0 mm from the edge of second main surface 1b of substrate 1 toward the other edge of the opposing second main surface. The outer periphery of conductive film 2 and the outer periphery of layers other than the lower layer included in conductive film 2 can also be defined in the same manner as above.

[0039] As described above, the conductive film 2 has a second film composition (second film). The material of the single layer film when the conductive film 2 is a single layer film, or the material of at least the upper layer when the conductive film 2 is a laminated film including an upper layer and a lower layer, is not particularly limited, as long as it does not impair the effects of the present disclosure. When the upper layer is a second film having the second film composition, the material of the upper layer is preferably different from the material of the lower layer. Examples of materials for the second film composition (second film) include materials (metals) containing at least one element selected from ruthenium (Ru), rhodium (Rh), molybdenum (Mo), niobium (Nb), titanium (Ti), zirconium (Zr), yttrium (Y), silicon (Si), palladium (Pd), silver (Ag), platinum (Pt), gold (Au), iridium (Ir), tungsten (W), cobalt (Co), manganese (Mn), tin (Sn), vanadium (V), nickel (Ni), iron (Fe), hafnium (Hf), copper (Cu), tellurium (Te), zinc (Zn), magnesium (Mg), germanium (Ge), aluminum (Al), osmium (Os), tantalum (Ta), and chromium (Cr). Furthermore, the material of the second film composition (second film) of the conductive film 2 may further contain, in addition to these elements, at least one element selected from oxygen (O), nitrogen (N), carbon (C), boron (B), hydrogen (H) and noble gases.

[0040] Among these materials, a material containing at least one metal selected from hafnium, niobium, ruthenium, iridium, and rhodium is particularly preferred as the material for the second film composition (second film) of the conductive film 2. For example, the material for the second film composition (second film) of the conductive film 2 can be any of the above metals or an alloy containing the above metals, and can also contain at least one or more selected from the group consisting of metals other than the above, oxygen (O), nitrogen (N), carbon (C), boron (B), hydrogen (H), and noble gases.

[0041] The hafnium-containing material as the second film composition (second film) is preferably composed of hafnium and one or more elements selected from oxygen, nitrogen, carbon, hydrogen, and noble gases. Such hafnium-containing materials can be easily removed using known cleaning solutions, and are therefore suitable for use as a removable upper layer included in the conductive film 2. In this case, the lower layer is preferably composed of, for example, a Ta-based material, as described below.

[0042] The niobium-containing material for the second film composition (second film) can be, for example, Nb alone or an Nb-based material such as an Nb alloy such as TaNb, RuNb, or CrNb. The Nb-based material can further contain one or more elements selected from oxygen, nitrogen, carbon, boron, hydrogen, and noble gases. Such Nb-based materials are preferred due to their high etching resistance. When the second film composition (second film) is made of an Nb-based material, the conductive film 2 may be either a single-layer film or a laminated film. When the upper layer of the laminated conductive film 2 is made of an Nb-based material, the material for the lower layer is not particularly limited, but is preferably made of a Cr-based material or a Ta-based material, as described below. When the lower layer is made of an Nb-based material, the material for the upper layer is not particularly limited, but is preferably made of a Cr-based material or a Ta-based material, as described below.

[0043] The ruthenium-containing material for the second film composition (second film) can be, for example, a Ru-based material, such as Ru compounds such as RuN, RuO, RuON, RuC, RuCN, RuCO, and RuCNO, Ru compounds containing hydrogen or a noble gas, or Ru alloys such as RuTa, RuCr, RuRh, and RuRhCr. The Ru alloy can further contain one or more elements selected from oxygen, nitrogen, carbon, hydrogen, and a noble gas. Ru-based materials such as these are preferred due to their high etching resistance. When the second film composition (second film) is made of a Ru-based material, the conductive film 2 may be either a single-layer film or a laminated film. When the upper layer of the laminated conductive film 2 is made of a Ru-based material, the lower layer is preferably made of a Cr-based material or a Ta-based material, as described below. When the lower layer is made of a Ru-based material, the upper layer is preferably made of a Cr-based material or a Ta-based material, as described below.

[0044] The iridium-containing material for the second film composition (second film) can be, for example, Ir alone or an Ir-based material such as an Ir alloy such as IrTa. The Ir-based material can further contain one or more elements selected from oxygen, nitrogen, carbon, hydrogen, and noble gases. The above-mentioned Ir-based materials are preferred due to their high etching resistance. When the second film composition (second film) is an Ir-based material, the conductive film 2 may be either a single-layer film or a laminated film. When the upper layer of the laminated conductive film 2 is made of an Ir-based material, the lower layer is preferably made of a Cr-based material or a Ta-based material, as described below. When the lower layer is made of an Ir-based material, the upper layer is preferably made of a Cr-based material or a Ta-based material, as described below.

[0045] The rhodium-containing material for the second film composition (second film) can be, for example, a Rh-based material such as Rh alone or an alloy containing Rh. The Rh-based material can further contain one or more elements selected from oxygen, nitrogen, carbon, hydrogen, and noble gases. The Rh-based material described above is preferred due to its high etching resistance. When the second film composition (second film) is a Rh-based material, the conductive film 2 may be either a single-layer film or a laminated film. When the upper layer of the laminated conductive film 2 is made of a Rh-based material, the lower layer is preferably made of a Cr-based material or a Ta-based material, as described below. When the lower layer is made of a Rh-based material, the upper layer is preferably made of a Cr-based material or a Ta-based material, as described below.

[0046] Furthermore, when the conductive film 2 is a laminated film including an upper layer and a lower layer, the material of the lower layer is not particularly limited as long as it does not impair the effects of the present disclosure. The material of the lower layer is preferably different from the material of the upper layer. Examples of the material of the lower layer include a material having different constituent elements from the material of the upper layer and a material having the same constituent elements as the material of the upper layer but in a different composition ratio. Examples of the material for the lower layer include materials containing at least one element selected from the group consisting of ruthenium (Ru), rhodium (Rh), molybdenum (Mo), niobium (Nb), titanium (Ti), zirconium (Zr), yttrium (Y), silicon (Si), palladium (Pd), silver (Ag), platinum (Pt), gold (Au), iridium (Ir), tungsten (W), cobalt (Co), manganese (Mn), tin (Sn), vanadium (V), nickel (Ni), iron (Fe), hafnium (Hf), copper (Cu), tellurium (Te), zinc (Zn), magnesium (Mg), germanium (Ge), aluminum (Al), osmium (Os), tantalum (Ta), and chromium (Cr). In addition to these elements, the material for the lower layer may further contain at least one element selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), boron (B), hydrogen (H), and noble gases. The lower layer is preferably made of a Cr-based material such as CrN, CrC, CrO, CrON, CrCN, CrOC, and CrOCN. Furthermore, from the viewpoint of mechanical properties, the lower layer is particularly preferably made of a Ta-based material containing tantalum (Ta), such as Ta alone, TaN, TaB, TaBN, TaO, TaON, TaBO, and TaBNO. When the lower layer is made of a Cr-based material, the upper layer can be made of, for example, a Ta-based material described below. When the lower layer is made of a Cr-based material, even if the upper layer is damaged by etching the first film using, for example, a fluorine-based gas, the lower layer made of a Cr-based material protects the second main surface of the substrate 1, thereby preventing or reducing exposure of the second main surface.

[0047] The thickness of the conductive film 2 is not particularly limited, but is preferably 10 nm or more, more preferably 20 nm or more, whether the conductive film 2 is a single-layer film or a laminated film. The thickness is preferably 500 nm or less, more preferably 200 nm or less, and even more preferably 100 nm or less. When the conductive film 2 is a laminated film, the thickness ratio of each layer is not particularly limited. The method for forming the conductive film 2 is not particularly limited, but magnetron sputtering, ion beam sputtering, or the like is usually preferred.

[0048] Furthermore, the conductive film 2 is preferably amorphous, which allows the surface of the conductive film 2 to be smooth and flat.

[0049] Furthermore, the conductive film 2 preferably has a compressive stress. When the conductive film 2 has a compressive stress, for example, when a multilayer reflective film is formed on the first main surface it of the substrate 1, warping of the substrate 1 caused by the multilayer reflective film can be reduced.

[0050] As described above, the present disclosure provides that, for example, in the substrate 10 with a conductive film of this embodiment, under the first etching conditions used to etch the first film 7, the etching selectivity of the first film 7 having the first film composition relative to the conductive film 2 having the second film composition or an upper layer (middle layer or lower layer) of the conductive film 2 is 0.8 or more or less than 0.

[0051] The first etching conditions used to etch the first film 7 vary depending on the film composition of the first film 7, but can be, for example, dry etching using a fluorine-based gas or a chlorine-based gas. The fluorine-based gas can be F ２ Gas, CF ４ Perfluorocarbon gases such as CFH ３ Hydrofluorocarbon gases such as SF ６ Gas, NF ３ Gas, SiF ４ Examples of the fluorine-based gas include fluorine gas and HF gas. These fluorine-based gases may further contain noble gases and / or oxygen. Examples of the chlorine-based gas include Cl. ２ , SiCl ２, CHCl ３ , C.H. ２ Cl ２ , CCl ４ , BCl ３ The chlorine-based gas may further include a noble gas and / or oxygen. Also, depending on the embodiment of the reflective mask, it may be wet etching.

[0052] In the present disclosure, the etching rate of the first film 7 under the first etching conditions is greater than 0. The first etching conditions can be, for example, conditions under which the etching rate of the first film 7 is greater than 0 and is at its maximum. For example, it is preferable that the etching rate of the first film 7 under the first etching conditions is 0.5 nm / sec or less, particularly 0.2 nm / sec or less, because this can better achieve the effects of the present disclosure. In particular, when the etching rate of the first film 7 is within the above range and the film thickness of the first film 7 is 15 nm or more, particularly 20 nm or more, the present disclosure is even more effective. In the present disclosure, the etching rate of the first film 7 under the first etching conditions is greater than 0. When the film thickness of the first film 7 is 10 nm or less, the effects of the present disclosure are better when the etching rate of the first film 7 is 0.02 nm / sec or less.

[0053] In the present disclosure, the above etching selectivity ratio of 0.8 or more means that the etching selectivity expressed with one significant digit is 0.8 or more. Furthermore, the above etching selectivity ratio of less than 0 means that the etching selectivity ratio is a negative value. Furthermore, the above etching selectivity ratio of less than 0 means that the etching rate of the first film 7 is greater than 0 and that, under the etching conditions for the first film 7 (first etching conditions), the film thickness of the conductive film 2 becomes larger than that before etching (the conductive film 2 expands).

[0054] In the present disclosure, for example, when the first film 7 is etched under the first etching conditions of this embodiment, the amount of film thickness reduction at the outer periphery of the conductive film 2 after etching of the first film 7 can be 20% or less of the film thickness at the outer periphery of the conductive film 2 before etching of the first film 7. The amount of film thickness reduction at the outer periphery of the conductive film 2 after etching of the first film 7 is preferably 15% or less, and more preferably 10% or less, of the film thickness at the outer periphery of the conductive film 2 before etching of the first film 7. The outer periphery of the conductive film 2 here is as described above. The outer periphery of the conductive film 2 can extend, for example, within 2.0 mm from the edge of the second main surface 1b of the substrate 1. If the film thickness at the outer periphery of the conductive film 2 is not constant within the plane, the amount of film thickness reduction can be calculated by subtracting the average film thickness at the outer periphery of the conductive film 2 after etching from the average film thickness at the outer periphery of the first film 7 before etching. When the thickness of the outer periphery of the conductive film 2 is not constant within the plane, for example, the thickness of the outer periphery of the conductive film 2 gradually decreases as it approaches the edge of the conductive film 2 in cross section.

[0055] As described above, according to the present disclosure, for example, under the first etching conditions used to etch the first film 7 in this embodiment, the etching selectivity of the first film composition of the first film 7 (or the first film 7) to the second film composition of the conductive film 2 (or the second film) is 0.8 or more or less than 0. Therefore, even when a material that is difficult to etch is used for the first film 7, for example, it is possible to suppress damage to the conductive film 2 caused by etching of the first film 7. For example, even when a material that is difficult to etch is used for the absorber film or the like, it is possible to reduce damage to the conductive film caused by etching of the absorber film or the like in the manufacturing process of a reflective mask.

[0056] [Substrate with Multilayer Reflective Film] Next, a multilayer reflective film-coated substrate using the conductive film-coated substrate of the present disclosure will be described. FIG. 2 is a cross-sectional view showing a multilayer reflective film-coated substrate according to an embodiment of the present disclosure. As shown in FIG. 2, a multilayer reflective film-coated substrate 20 according to an embodiment of the present disclosure has a multilayer reflective film 3 that reflects EUV light, which is exposure light, formed on the first main surface 1t of the substrate 1 in the conductive film-coated substrate 10 (the upper surface of the substrate 1 in FIG. 2). That is, in this case, the first film 7 in the conductive film-coated substrate 10 can be the multilayer reflective film 3.

[0057] The multilayer reflective film-coated substrate 20 of this embodiment is produced by forming a multilayer reflective film 3 that reflects exposure light, for example, EUV light, on the first main surface 1t of the substrate 1 of the conductive film-coated substrate 10. A mask blank (reflective mask blanks 30, 40, 50) described below and a reflective mask 60 described below both include the multilayer reflective film 3 on the first main surface 1t of the substrate 1 of the conductive film-coated substrate 10, and are therefore types of the multilayer reflective film-coated substrate 20.

[0058] The multilayer reflective film 3 is a multilayer film in which low-refractive index layers and high-refractive index layers are alternately stacked. The multilayer reflective film 3 is generally a multilayer film in which thin films of heavy elements or their compounds and thin films of light elements or their compounds are alternately stacked in approximately 30 to 60 periods. For example, a Mo / Si periodic stacked film in which Mo films and Si films are alternately stacked in approximately 40 periods is preferably used as a multilayer reflective film for EUV light with a wavelength of 13 to 14 nm. Other multilayer reflective films used in the EUV light range include Ru / Si periodic multilayer films, Mo / Be periodic multilayer films, Mo compound / Si compound periodic multilayer films, Si / Nb periodic multilayer films, Si / Mo / Ru periodic multilayer films, Si / Mo / Ru / Mo periodic multilayer films, and Si / Ru / Mo / Ru periodic multilayer films. The material of the multilayer reflective film can be appropriately selected depending on the exposure wavelength.

[0059] Typically, a protective film 4 is preferably provided on the multilayer reflective film 3 to protect the multilayer reflective film during absorber film patterning or absorber film pattern modification (see FIG. 4 ). The protective film is sometimes called a capping layer. Such a protective film 4 can be formed, for example, from a material containing ruthenium as a primary component. Examples of materials containing ruthenium as a primary component include Ru metal alone, Ru alloys containing Ru with at least one metal selected from titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), zirconium (Zr), yttrium (Y), boron (B), lanthanum (La), cobalt (Co), chromium (Cr), and rhenium (Re), and materials containing nitrogen and / or oxygen. The protective film 4 may be formed, for example, from a material containing rhodium as a primary component. Furthermore, the protective film 4 may have, for example, a layer containing ruthenium as a primary component and a layer containing rhodium as a primary component. Incidentally, containing substance A as a main component means containing 50 atomic % or more of substance A. The thickness of the protective film 4 is preferably, for example, 1 nm or more. The thickness of the protective film 4 is preferably 5 nm or less.

[0060] In a substrate with a multilayer reflective film, which is provided on the first main surface 1t of the conductive film-coated substrate 10 with a multilayer reflective film 3 including alternating high refractive index layers and low refractive index layers, or the multilayer reflective film 3 and the protective film formed on the multilayer reflective film 3, the first film 7 can be the multilayer reflective film 3 or the protective film 4.

[0061] The method for forming the multilayer reflective film 3 and the protective film 4 is not particularly limited, but ion beam sputtering or magnetron sputtering is usually preferred.

[0062] In the multilayer reflective film coated substrate 20 of this embodiment, under etching conditions (first etching conditions) used to etch the multilayer reflective film 3 or the protective film 4, the etching selectivity of the multilayer reflective film 3 or the protective film 4 to the conductive film 2 or an upper layer (middle layer or lower layer) of the conductive film 2 is 0.8 or more or less than 0. This makes it possible to suppress damage to the conductive film 2 caused by etching the multilayer reflective film 3 or the protective film 4, even when, for example, a material that is difficult to etch is used for the multilayer reflective film 3 or the protective film 4.

[0063] [Mask Blank] Next, a mask blank using the conductive film-coated substrate of the present disclosure will be described. The mask blank of the present disclosure includes a multilayer reflective film formed on the first main surface of the conductive film-coated substrate and including alternating high-refractive-index layers and low-refractive-index layers; a first film formed on the multilayer reflective film and having a first film composition; and a conductive film formed on the second main surface and having a second film composition (second film). The mask blank of the present disclosure has an etching selectivity of the first film composition (first film) to the second film composition (second film) under first etching conditions used to etch the first film, of 0.8 or more or less than 0.

[0064] 3 is a cross-sectional view showing a reflective mask blank, which is a mask blank using a conductive film-coated substrate according to an embodiment of the present disclosure. As shown in Fig. 3, in a reflective mask blank 30 according to an embodiment of the present disclosure, a multilayer reflective film 3 that reflects EUV light, which is exposure light, is formed on the first main surface 1t (the upper surface of the substrate 1 in Fig. 3) of the substrate 1 in the conductive film-coated substrate 10, and an absorber film 5 is formed on the multilayer reflective film 3. The conductive film 2 is formed on the second main surface 1b of the substrate 1. That is, in the reflective mask blank 30 of this embodiment, the first film formed on the multilayer reflective film 3 and having a first film composition can be the absorber film 5.

[0065] The reflective mask blank 30 is produced by depositing, in this order, a multilayer reflective film 3 that reflects EUV light and an absorber film 5 that absorbs EUV light on the first main surface 1t of the substrate 1 of the conductive film-coated substrate 10.

[0066] The absorber film 5 can absorb exposure light, for example, EUV light. More specifically, in a reflective mask 60 (see FIG. 6 ) obtained by patterning the absorber film 5 of the reflective mask blank, the absorber film 5 is configured so that light reflected by the absorber film pattern 5 a (see FIG. 6 ) has a desired reflectance difference with respect to light reflected by the multilayer reflective film 3 or the protective film 4 on the multilayer reflective film 3. For example, the reflectance difference of the absorber film 5 with respect to EUV light is selected between 0.1% and 40%. Furthermore, in addition to the reflectance difference, the absorber film 5 may be configured so that light reflected by the absorber film pattern 5 a irradiated with EUV light has a desired phase difference with respect to light reflected by the multilayer reflective film 3 or the protective film 4 irradiated with EUV light. Incidentally, when light reflected by the absorber film pattern 5 a irradiated with EUV light has a desired phase difference with respect to light reflected by the multilayer reflective film 3 or the protective film 4 irradiated with EUV light, the absorber film 5 in the reflective mask blank may be referred to as a phase shift film. When contrast is improved by providing a desired phase difference between light reflected by the multilayer reflective film 3 or the protective film 4 and light reflected by the absorber film pattern 5 a, the phase difference with respect to EUV light is preferably set in the range of 150 degrees to 310 degrees, and the reflectance difference of the absorber film 5 with respect to EUV light is preferably set to 3% or more and 40% or less.

[0067] The absorber film 5 may have a single layer or a laminated structure. When the absorber film 5 has a laminated structure, the absorber film 5 may be composed of a laminated film of the same material or a laminated film of different materials. The laminated film may have a material and / or composition that changes stepwise and / or continuously in the film thickness direction. When the absorber film 5 is a laminated film, the absorber film 5 may include, for example, a layer (buffer layer) having etching selectivity with respect to the protective film at a position closest to the substrate in the film thickness direction.

[0068] The material of the absorber film 5 is not particularly limited, as long as it absorbs EUV light, can be processed by etching or the like, and has a high etching selectivity with respect to the multilayer reflective film 3 or the protective film 4. The material of the absorber film 5 is preferably etchable by dry etching using a chlorine (Cl)-based gas and / or a fluorine (F)-based gas. As a material for the absorber film 5 having the above-described functions, 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), osmium (Os), and silicon (Si), an alloy containing two or more metals, or a compound thereof can be preferably used. The material of the absorber film 5 may contain oxygen (O), nitrogen (N), carbon (C), hydrogen (H) and / or boron (B) in addition to the above metals, alloys or compounds.

[0069] The thickness of the absorber film 5 is preferably within a range of, for example, about 30 nm to 100 nm. There are no particular restrictions on the method for forming the absorber film 5, but magnetron sputtering, ion beam sputtering, or the like is usually preferred.

[0070] The configuration of the multilayer reflective film 3 in the reflective mask blank 30 is as described above for the multilayer reflective film-coated substrate. In this embodiment, examples of the material for the multilayer reflective film 3 include the same materials as those for the multilayer reflective film described above for the multilayer reflective film-coated substrate.

[0071] Details regarding the configuration of the conductive film 2 in the reflective mask blank 30 are as explained above for the substrate with a conductive film. That is, the conductive film 2 may be a single-layer film or a laminated film. The laminated film has an upper layer farthest from the substrate 1 and a lower layer formed between the upper layer and the second main surface 1b of the substrate 1. The conductive film 2 may include an intermediate layer between the upper layer and the lower layer.

[0072] In this embodiment, the material of the conductive film 2, when it is a single layer, or the material of at least the upper layer, when it is a laminated film including an upper layer and a lower layer, may be the same as the materials of the conductive film described above for the conductive film-coated substrate. The same applies to the intermediate layer and the lower layer. The upper layer may be removed, if necessary, when creating a reflective mask. When the upper layer is removed, it is preferably made of an easily removable material, such as hafnium (Hf), aluminum (Al), nickel (Ni), titanium (Ti), or yttrium (Y).

[0073] The thickness of the conductive film 2 is not particularly limited in this embodiment either, but can be the same as that of the conductive film 2 described above in the substrate 10 with a conductive film.

[0074] The conductive film 2 is preferably amorphous and has a compressive stress.

[0075] As described above, in the reflective mask blank 30 of this embodiment, under the etching conditions (first etching conditions) used to etch the absorber film 5 (first film), the etching selectivity of the absorber film 5 relative to the conductive film 2 or an upper layer (middle layer or lower layer) of the conductive film 2 is 0.8 or more or less than 0.

[0076] The etching conditions used for etching the absorber film 5 vary depending on the film composition of the absorber film 5, but may be, for example, dry etching using a fluorine-based gas or a chlorine-based gas.

[0077] The etching rate of the absorber film 5 under these etching conditions (first etching conditions) is preferably 0.5 nm / sec or less, more preferably 0.2 nm / sec or less. The etching rate of the absorber film 5 under these first etching conditions is greater than 0.

[0078] When the absorber film 5 is etched under the first etching conditions of this embodiment, the amount of film thickness reduction at the outer periphery of the conductive film 2 after etching of the absorber film 5 can be 20% or less of the film thickness at the outer periphery of the conductive film 2 before etching of the absorber film 5. The amount of film thickness reduction at the outer periphery of the conductive film 2 after etching of the absorber film 5 is preferably 15% or less, and more preferably 10% or less, of the film thickness at the outer periphery of the conductive film 2 before etching of the absorber film 5.

[0079] As described above, according to the present disclosure, for example, under the etching conditions (first etching conditions) used to etch the absorber film 5 in this embodiment, the etching selectivity of the absorber film 5 to the conductive film 2 or an upper layer (middle layer or lower layer) of the conductive film 2 is 0.8 or more or less than 0. Therefore, even when a material that is difficult to etch is used for the absorber film 5, for example, damage to the conductive film 2 caused by etching of the absorber film 5 can be suppressed in the manufacturing process of a reflective mask using the reflective mask blank 30 of this embodiment.

[0080] 4 is a cross-sectional view showing a reflective mask blank according to another embodiment of the present disclosure. As shown in FIG. 4, a reflective mask blank 40 of this embodiment has the aforementioned protective film 4 on the surface of the multilayer reflective film 3. That is, the protective film 4 is formed between the multilayer reflective film 3 and the absorber film 5. The protective film 4 is as described above. The details of the configurations of the multilayer reflective film 3, absorber film 5, and conductive film 2 in this embodiment are the same as those in the previously described embodiments.

[0081] 5 is a cross-sectional view showing a reflective mask blank according to another embodiment of the present disclosure. As shown in Fig. 5, in the reflective mask blank 50 of this embodiment, an etching mask film 6 is formed on the absorber film 5.

[0082] The etching mask film 6 functions as a mask when patterning the absorber film 5. The etching mask film 6 is composed of a material with etching selectivity different from that of the material of the top layer of the absorber film 5. The material of the etching mask film 6 can be, for example, the materials listed above as the materials for the absorber film 5. An appropriate material for the etching mask film 6 can be selected depending on the material of the absorber film 5. For example, when the absorber film 5 is Ta alone or a material containing Ta, the etching mask film 6 can be made of a material such as chromium, a chromium compound, silicon, or a silicon compound. Examples of chromium compounds include materials containing Cr and at least one element selected from N, O, C, and H. Examples of silicon compounds include materials containing Si and at least one element selected from N, O, C, and H, metal silicon (metal silicide) containing silicon or a silicon compound and a metal, and metal silicon compounds (metal silicide compounds). Examples of metal silicon compounds include materials containing a metal, Si, and at least one element selected from N, O, C, and H. When the absorber film 5 is a laminated film in which a material containing Ta and a material containing Cr are formed in this order on the multilayer reflective film 3, the material of the etching mask film 6 can be selected from silicon, silicon compounds, metal silicides, metal silicide compounds, and the like, which have etching selectivity different from that of materials containing Cr.

[0083] Furthermore, in the reflective mask blank 50 according to this embodiment (the same applies to the above-mentioned reflective mask blanks 30 and 40), the absorber film 5 can be configured as a laminated film of a top layer and other layers made of materials with different etching selectivities, with the top layer functioning as an etching mask film for the other layers.

[0084] The details of the configurations of the multilayer reflective film 3, the absorber film 5 and the conductive film 2 in this embodiment are the same as those in the previously described embodiment.

[0085] In the reflective mask blank 50 of this embodiment, under etching conditions (first etching conditions) used to etch the etching mask film 6 or the absorber film 5, the etching selectivity of the etching mask film 6 or the absorber film 5 to the conductive film 2 or an upper layer (middle layer or lower layer) of the conductive film 2 is 0.8 or more or less than 0. Therefore, even when a material that is difficult to etch is used for the etching mask film 6 or the absorber film 5, damage to the conductive film 2 caused by etching the etching mask film 6 or the absorber film 5 can be suppressed in the manufacturing process of a reflective mask using the reflective mask blank 50 of this embodiment.

[0086] The reflective mask blanks 30, 40, and 50 according to the above-described embodiments also include an embodiment in which a resist film is formed on the absorber film 5 or the etching mask film 6. Such a resist film is used when the absorber film 5 in the reflective mask blank is patterned by lithography.

[0087] [Reflective Mask] The present disclosure also provides a reflective mask fabricated using the above-described reflective mask blank 30 or the like. The reflective mask of the present invention comprises a multilayer reflective film formed on the first main surface of the conductive film-coated substrate and including alternating high-refractive-index layers and low-refractive-index layers; a first film formed on the multilayer reflective film and having a first film composition; and a conductive film formed on the second main surface and having a second film composition (second film). The first film has a transfer pattern, and under first etching conditions used to etch the first film, the etching selectivity of the first film composition (first film) to the second film composition (second film) is 0.8 or more or less than 0.

[0088] 6 is a cross-sectional view showing a reflective mask according to an embodiment of the present disclosure. As shown in Fig. 6, the reflective mask 60 of this embodiment has an absorber film pattern 5a obtained by patterning the absorber film 5 of the reflective mask blank 40 described above by etching, for example. In the reflective mask 60 of this embodiment, the absorber film 5 is a first film formed on the multilayer reflective film 3 and having a first film composition.

[0089] For example, EUV (or electron beam) lithography is the most suitable method for patterning the absorber film 5, which will become the transfer pattern in the reflective mask blank 40. That is, a resist film is formed by baking an electron beam lithography resist applied to the reflective mask blank 40. An electron beam lithography device is used to write on the resist film, and development is performed to form a resist pattern corresponding to the transfer pattern (absorber film pattern 5a) on the resist film. Thereafter, the absorber film 5 is patterned using this resist pattern as a mask to form the absorber film pattern 5a. In this manner, the reflective mask 60 shown in FIG. 6 is produced.

[0090] The protective film 4 exposed by forming the absorber film pattern 5a may be eventually removed, but does not have to be removed if it remains and does not affect its function as a reflective mask. Furthermore, when a reflective mask is manufactured using a reflective mask blank 50 having a configuration including the etching mask film 6 described above, the etching mask film 6 may be eventually removed, but does not have to be removed if it remains and does not affect its function as a reflective mask.

[0091] As described above, even when a material that is difficult to etch is used for the etching mask film 6 or the absorber film 5, damage to the conductive film 2 caused by etching of the etching mask film 6 or the absorber film 5 can be suppressed, for example, in the manufacturing process of a reflective mask using a reflective mask blank 50.

[0092] The present disclosure also provides a substrate with a conductive film according to another embodiment. FIG. 7 is a cross-sectional view showing a substrate with a conductive film according to another embodiment of the present disclosure. As shown in FIG. 7 , a substrate with a conductive film 70 according to this embodiment includes a substrate 1 having a first main surface 1t (the upper surface of the substrate 1 in FIG. 7 ) and a second main surface 1b (the lower surface of the substrate 1 in FIG. 7 ) facing the first main surface, a first film 7 formed on the first main surface 1t, and a conductive film 2 formed on the second main surface 1b. The thickness of the conductive film 2 near the periphery is formed to be larger (thicker) than the thickness of the conductive film 2 at the center. When the first film 7 is etched under first etching conditions used for etching the first film 7, the thickness of the conductive film 2 near the periphery is formed to be larger (thicker) in advance, taking into account the amount of film loss in the outer periphery of the conductive film 2 after etching the first film 7. As a result, even if the conductive film 2 is damaged, particularly in its outer periphery, by etching the first film 7 under the first etching conditions used for etching the first film 7, the desired film thickness of the conductive film 2 can be maintained.

[0093] The above-mentioned multilayer reflective film-coated substrate 70 includes a conductive film 2 on the second main surface 1b of the substrate 1, and is therefore a type of conductive film-coated substrate 70. In addition, the above-mentioned mask blanks (reflective mask blanks 30, 40, 50) and the above-mentioned reflective mask 60 both include a conductive film 2 on the second main surface 1b of the substrate 1, and are therefore a type of conductive film-coated substrate 70.

[0094] The outer periphery of the conductive film 2 is as described above with respect to the conductive film-coated substrate 10. The outer periphery of the conductive film 2 may be, for example, a region within 2.0 mm from the edge of the second main surface 1b of the substrate 1. The cross-sectional shape of the outer periphery of the conductive film 2 is not limited to that shown in the figure and may be any shape. The thickness of the outer periphery of the conductive film 2 does not need to be constant; for example, it is sufficient that the average thickness of the outer periphery is greater than the thickness of the central portion of the conductive film 2. It is preferable that the thickness of the outer periphery of the conductive film 2 is greater than the thickness of the central portion of the conductive film 2 over the entire surface of the outer periphery of the conductive film 2. This allows the thickness of the outer periphery of the conductive film 2 after etching of the first film to be maintained within an appropriate range.

[0095] The film thickness of the outer periphery of the conductive film 2 may be greater, for example, as it approaches the edge of the second main surface 1b of the substrate 1. In this case, the film thickness of the outer periphery of the conductive film 2 may increase continuously or stepwise as it approaches the edge of the second main surface 1b of the substrate 1. That is, in a cross-sectional view, the conductive film 2 may have a gradient region in which the film thickness changes continuously or stepwise in the outer periphery. Furthermore, the film thickness of the outer periphery of the conductive film 2 may be constant in a region within 2.0 mm from the second main surface 1b of the substrate 1 or the edge of the conductive film 2.

[0096] The thickness of the conductive film 2 at the outer periphery is preferably 10% or more larger, more preferably 15% or more larger, and even more preferably 20% or more larger than the thickness of the conductive film 2 at the center. When the thickness of the conductive film 2 at the outer periphery is not uniform across the surface, the largest thickness at the outer periphery is preferably 10% or more larger, more preferably 15% or more larger, and even more preferably 20% or more larger than the thickness at the center. These configurations allow the conductive film 2 to more effectively maintain a desired thickness. Furthermore, the difference between the thickness of the conductive film 2 at the outer periphery and the thickness at the center is preferably 40% or less, more preferably 30% or less, of the thickness at the center. When the thickness of the conductive film 2 at the outer periphery is not uniform across the surface, the difference between the largest thickness at the outer periphery and the thickness at the center is preferably 40% or less, more preferably 30% or less, of the thickness at the center. These configurations allow the thickness of the conductive film 2 at the outer periphery to be maintained within an appropriate range after etching the first film. Furthermore, it is possible to suppress problems with the electrostatic chuck attracting the substrate, deterioration in the quality of the reflective mask, and deterioration in the pattern transfer accuracy.

[0097] To increase the thickness of the outer periphery of the conductive film 2, the following steps may be performed. First, as a first film formation, a conductive film 2 is formed on the second main surface 1b of the substrate 1, similar to the conductive film 2 described above for the conductive film-coated substrate 10. Then, as a second film formation, an additional film is formed while shielding the area other than the outer periphery so that only the outer periphery of the conductive film 2 is exposed. The film formed in the second film formation also constitutes part of the conductive film 2. The sputtering gas used in the second film formation may be the same as that used in the first film formation, or may be different from that used in the first film formation, as necessary. In the second film formation, the sputtering target used in the first film formation may be used as is, or a different sputtering target may be used. That is, the material of the conductive film 2 formed in the second film formation may be the same as the material of the conductive film 2 formed in the first film formation, or may be different from the material of the conductive film 2 formed in the first film formation.

[0098] The details of the configuration of the conductive film 2 other than the film thickness can be the same as those described for the above-mentioned conductive film-coated substrate 10. The material of the conductive film 2 is not particularly limited as long as the film thickness of the outer periphery of the conductive film 2 is greater than the film thickness of the center of the conductive film 2, but can be the same as the material of the conductive film 2 described for the above-mentioned conductive film-coated substrate 10, for example.

[0099] [Method for Manufacturing a Semiconductor Device] The present disclosure also provides a method for manufacturing a semiconductor device. By using the reflective mask 60 of the present disclosure to expose and transfer the transfer pattern (absorber film pattern 5 a) onto a transfer target, for example, a resist film on a semiconductor substrate, a high-quality semiconductor device with few defects can be manufactured.

[0100] A reflective mask manufactured from a mask blank using a substrate with a conductive film according to the present disclosure suffers little damage to the conductive film. This does not affect the substrate attracting force of an electrostatic chuck, the quality of the reflective mask, or the pattern transfer accuracy. Therefore, by performing pattern transfer using this reflective mask 60 with little damage to the conductive film, good substrate attracting force can be obtained by the electrostatic chuck. This allows for high-precision pattern transfer without misalignment during exposure.

[0101] As described above in detail, according to the present disclosure, even when a material that is difficult to etch is used for the absorber film or the like, a substrate with a conductive film can be obtained in which the conductive film is less damaged by etching the absorber film or the like during mask manufacturing. Furthermore, a reflective mask manufactured from a mask blank using a substrate with a conductive film of the present disclosure suffers less damage to the conductive film. Therefore, there is no impact on the substrate attracting force of an electrostatic chuck or the pattern transfer accuracy. Furthermore, in the manufacture of semiconductor devices using this reflective mask, good substrate attracting force of an electrostatic chuck can be obtained by performing pattern transfer using this reflective mask that causes less damage to the conductive film. Therefore, high-precision pattern transfer can be performed without causing transfer position misalignment during exposure.

[0102] Hereinafter, the embodiments of the present disclosure will be described in more detail with reference to examples. ２ -TiO ２ A glass substrate of the same type was prepared. The glass substrate 1 was a 6-inch square substrate, measuring approximately 152.0 mm x 152.0 mm and approximately 6.35 mm thick. This glass substrate 1 had been mechanically polished to have a smooth surface with a root-mean-square roughness (Rq) of 0.25 nm and a flatness of 100 nm or less. The surface roughness was measured with an atomic force microscope (AFM), and the measurement area was 1 μm x 1 μm. Hereinafter, this glass substrate 1 may be simply referred to as the substrate.

[0103] First, a conductive film 2 made of Rh was formed on the back surface (second main surface) 1b of the substrate 1. More specifically, the substrate 1 was placed in a sputtering apparatus, and a Rh film with a thickness of 70 nm was formed using a Rh target and argon (Ar) as a sputtering gas.

[0104] Next, using an ion beam sputtering apparatus, 40 periods of Si films (film thickness: 4.2 nm) and Mo films (film thickness: 2.8 nm) were stacked on the surface (first main surface) 1t of the substrate 1 opposite to the conductive film 2, and finally a Si film (film thickness: 4 nm) was formed to form a multilayer reflective film 3. Furthermore, a protective film 4 (film thickness: 2.5 nm) made of Ru was formed on the Si film farthest from the substrate surface, thereby obtaining a substrate with a multilayer reflective film.

[0105] Next, using a DC magnetron sputtering device, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate. The CrN film was formed by DC magnetron sputtering. The CrN film was formed using a Cr target and a mixed gas of argon and nitrogen (flow ratio (%) Ar:N) as a sputtering gas. ２ The composition ratio of the CrN film was Cr:N=90 atomic %:10 atomic %. The PtRu film was formed by DC magnetron sputtering using a target containing Pt and Ru and argon (Ar) as the sputtering gas. The composition ratio of the PtRu film was Pt:Ru=45 atomic %:55 atomic %. In this manner, a reflective mask blank 40 was obtained (see FIG. 4).

[0106] Next, a reflective mask 60 was produced using the above-described reflective mask blank 40. First, a resist for electron beam lithography was applied to the reflective mask blank 40 and baked to form a resist film. A predetermined mask pattern was written on this resist film using an electron beam, and development was performed to form a resist pattern.

[0107] This resist pattern was used as a mask, and CF was used as a fluorine-based gas. ４ and He mixed gas (flow ratio (%) CF ４ :He=60:40) to form a PtRu film, and ２ and O ２The CrN film was etched using a mixed gas of 1,000 ppm and 1,000 ppm (a mixed gas of 1,000 ppm and 1,000 ppm), thereby forming an absorber film pattern 5a on the protective film 4. Furthermore, the resist pattern on the absorber film pattern 5a was removed, thereby obtaining a reflective mask 60 (see FIG. 6).

[0108] In Example 1, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the conductive film 2 was 1.4. Furthermore, the etching rate of the PtRu film serving as the absorber upper layer under the first etching conditions was 0.03 nm / sec. After etching the PtRu film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, after etching the PtRu film serving as the absorber upper layer under the first etching conditions, the amount of film thickness reduction at the outer periphery of the conductive film 2 was 20% or less of the film thickness at the outer periphery of the conductive film 2 before etching the PtRu film. That is, even when a material that is difficult to etch is used for the absorber film 5, damage to the conductive film 2 caused by etching the absorber film 5 during the manufacturing process of the reflective mask 60 was suppressed.

[0109] The reflective mask 60 of this Example 1 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0110] Example 2 A conductive film 2 made of Ir was formed on the rear surface 1b of a substrate 1 prepared in the same manner as in Example 1. More specifically, the substrate 1 was placed in a sputtering device, and an Ir film with a thickness of 70 nm was formed using an Ir target and argon (Ar) as a sputtering gas.

[0111] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0112] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ).

[0113] Next, a reflective mask 60 was fabricated in the same manner as in Example 1 using the reflective mask blank 40 .

[0114] In Example 2, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the conductive film 2 was 2.6. Furthermore, the etching rate of the PtRu film serving as the absorber upper layer under the first etching conditions was 0.03 nm / sec. After etching of the PtRu film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, after etching of the PtRu film serving as the absorber upper layer under the first etching conditions, the amount of film thickness reduction at the outer periphery of the conductive film 2 was 20% or less of the film thickness at the outer periphery of the conductive film 2 before etching of the PtRu film. That is, even when a material that is difficult to etch is used for the absorber film 5, damage to the conductive film 2 caused by etching of the absorber film 5 during the manufacturing process of the reflective mask 60 was suppressed.

[0115] The reflective mask 60 of Example 2 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0116] Example 3 A conductive film 2 made of RuN was formed on the rear surface 1b of a substrate 1 prepared in the same manner as in Example 1. More specifically, the substrate 1 was placed in a sputtering device, and a Ru target and argon (Ar) and nitrogen (N) were used as sputtering gases. ２ ) mixed gas (flow ratio (%) Ar:N ２A RuN film having a thickness of 70 nm was formed by reactive sputtering using a mixture of Ru and N (Ru:N=55:45). The composition ratio of the RuN film was 94 atomic %:6 atomic %.

[0117] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0118] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ).

[0119] Next, a reflective mask 60 was fabricated in the same manner as in Example 1 using the reflective mask blank 40 .

[0120] In Example 3, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the conductive film 2 was 1.63. Furthermore, the etching rate of the PtRu film serving as the absorber upper layer under the first etching conditions was 0.03 nm / sec. After etching the PtRu film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, after etching the PtRu film serving as the absorber upper layer under the first etching conditions, the amount of film thickness reduction at the outer periphery of the conductive film 2 was 20% or less of the film thickness at the outer periphery of the conductive film 2 before etching the PtRu film. That is, even when a material that is difficult to etch is used for the absorber film 5, damage to the conductive film 2 caused by etching the absorber film 5 during the manufacturing process of the reflective mask 60 was suppressed.

[0121] The reflective mask 60 of Example 3 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0122] Example 4 A conductive film 2 made of RuCrN was formed on the rear surface 1b of a substrate 1 prepared in the same manner as in Example 1. More specifically, the substrate 1 was placed in a sputtering device, and a RuCr target and argon (Ar) and nitrogen (N) were used as sputtering gases. ２ ) mixed gas (flow ratio (%) Ar:N ２ A RuCrN film having a thickness of 70 nm was formed by reactive sputtering using a mixture of Ru, Cr, and N (Ru:Cr:N=55:45). The composition ratio of the RuCrN film was 84 atomic %:12 atomic %:4 atomic %.

[0123] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0124] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ).

[0125] Next, a reflective mask 60 was fabricated in the same manner as in Example 1 using the reflective mask blank 40 .

[0126] In Example 4, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the conductive film 2 was −1.08. Furthermore, the etching rate of the PtRu film serving as the absorber upper layer under the first etching conditions was 0.03 nm / sec. After etching the PtRu film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, the film thickness of the RuCrN film serving as the conductive film 2 after etching the PtRu film was greater than that before etching the PtRu film. Therefore, the film thickness reduction amount of the conductive film 2 at the outer periphery after etching the PtRu film serving as the absorber upper layer under the first etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film 2 before etching the PtRu film. That is, even when a material that is difficult to etch is used for the absorber film 5, damage to the conductive film 2 caused by etching the absorber film 5 during the manufacturing process of the reflective mask 60 can be suppressed.

[0127] The reflective mask 60 of Example 4 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0128] Example 5 A conductive film 2 made of RuNb was formed on the rear surface 1b of a substrate 1 prepared in the same manner as in Example 1. Specifically, the substrate 1 was placed in a sputtering device, and a RuNb film with a thickness of 70 nm was formed using a RuNb target and argon (Ar) gas as the sputtering gas. The composition ratio of the RuNb film was Ru:Nb=80 atomic %:20 atomic %.

[0129] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0130] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ).

[0131] Next, a reflective mask 60 was fabricated in the same manner as in Example 1 using the reflective mask blank 40 .

[0132] In Example 5, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the conductive film 2 was 0.96. Furthermore, the etching rate of the PtRu film serving as the absorber upper layer under the first etching conditions was 0.03 nm / sec. After etching of the PtRu film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, after etching of the PtRu film serving as the absorber upper layer under the first etching conditions, the amount of film thickness reduction at the outer periphery of the conductive film 2 was 20% or less of the film thickness at the outer periphery of the conductive film 2 before etching of the PtRu film. That is, even when a material that is difficult to etch is used for the absorber film 5, damage to the conductive film 2 caused by etching of the absorber film 5 during the manufacturing process of the reflective mask 60 was suppressed.

[0133] The reflective mask 60 of this Example 5 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0134] Example 6 A conductive film 2 made of RuRhCrN was formed on the rear surface 1b of a substrate 1 prepared in the same manner as in Example 1. More specifically, the substrate 1 was placed in a sputtering device, and a RuRhCr target and argon (Ar) and nitrogen (N) were used as sputtering gases. ２ ) mixed gas (flow ratio (%) Ar:N２ A RuRhCrN film having a thickness of 70 nm was formed by reactive sputtering using a mixture of Ru, Rh, Cr, and N (Ru:Rh:Cr:N=55:45). The composition ratio of the RuRhCrN film was 60 atomic %:30 atomic %:6 atomic %:4 atomic %.

[0135] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0136] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ).

[0137] Next, a reflective mask 60 was fabricated in the same manner as in Example 1 using the reflective mask blank 40 .

[0138] In Example 6, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the conductive film 2 was 1.86. Furthermore, the etching rate of the PtRu film serving as the absorber upper layer under the first etching conditions was 0.03 nm / sec. After etching the PtRu film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, after etching the PtRu film serving as the absorber upper layer under the first etching conditions, the amount of film thickness reduction at the outer periphery of the conductive film 2 was 20% or less of the film thickness at the outer periphery of the conductive film 2 before etching the PtRu film. That is, even when a material that is difficult to etch is used for the absorber film 5, damage to the conductive film 2 caused by etching the absorber film 5 during the manufacturing process of the reflective mask 60 was suppressed.

[0139] The reflective mask 60 of Example 6 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0140] Example 7 A conductive film 2 consisting of a TaNb film as a lower layer and a CrN film as an upper layer was formed on the back surface 1b of a substrate 1 prepared in the same manner as in Example 1. More specifically, the substrate 1 was placed in a sputtering device, and a TaNb film with a thickness of 60 nm was formed using a TaNb target and xenon (Xe) as sputtering gas. The composition ratio of the TaNb film was Ta:Nb = 80 atomic %: 20 atomic %. Subsequently, a Cr target and argon (Ar) and nitrogen (N) as sputtering gas were used to form a conductive film 2 on the back surface 1b of the substrate 1 prepared in the same manner as in Example 1. ２ ) mixed gas (flow ratio (%) Ar:N ２ A 10 nm thick CrN film was formed using a CrN film having a composition ratio of Cr:N=90 atomic %:10 atomic %.

[0141] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0142] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ).

[0143] Next, a reflective mask 60 was fabricated in the same manner as in Example 1 using the reflective mask blank 40 .

[0144] In Example 7, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the CrN film serving as the conductive film 2 upper layer was −1.63. Furthermore, the etching rate of the PtRu film serving as the absorber upper layer under the first etching conditions was 0.03 nm / sec. After etching the PtRu film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, the thickness of the CrN film serving as the upper layer of the conductive film 2 after etching the PtRu film was greater than that before etching the PtRu film. Therefore, under the first etching conditions, the amount of film thickness reduction at the outer periphery of the CrN film serving as the upper layer of the conductive film 2 after etching the PtRu film serving as the absorber upper layer was 20% or less of the thickness at the outer periphery of the CrN film serving as the upper layer of the conductive film 2 before etching the PtRu film. Furthermore, the TaNb film underlying the conductive film 2 was not damaged, and the film thickness of the TaNb film did not change before and after etching of the PtRu film. That is, even when a material that is difficult to etch was used for the absorber film 5, damage to the conductive film 2 caused by etching of the absorber film 5 in the manufacturing process of the reflective mask 60 could be suppressed.

[0145] The reflective mask 60 of Example 7 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0146] Example 8 A conductive film 2 consisting of a TaN film as a lower layer and a Hf film as an upper layer was formed on the rear surface 1b of a substrate 1 prepared in the same manner as in Example 1. More specifically, the substrate 1 was placed in a sputtering apparatus, and a Ta target and xenon (Xe) and nitrogen (N) were used as sputtering gases. ２ ) mixed gas (flow ratio (%) Xe:N ２A 60 nm thick TaN film was formed by reactive sputtering using a Ta:N ratio of 60:40. The composition ratio of the TaN film was Ta:N = 74 atomic %: 26 atomic %. Subsequently, a 10 nm thick Hf film was formed using a Hf target and xenon (Xe) as the sputtering gas.

[0147] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0148] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ).

[0149] Next, a reflective mask 60 was fabricated using the above-described reflective mask blank 40. First, an absorber film pattern 5a was formed on the protective film 4 in the same manner as in Example 1. Next, the Hf film as the upper layer of the conductive film 2 was removed using an SPM cleaning solution. Furthermore, the resist pattern on the absorber film pattern 5a was removed to obtain a reflective mask 60. It is noted that the Hf film as the upper layer of the conductive film 2 may be left as it is without being removed.

[0150] In Example 8, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the Hf film serving as the conductive film 2 upper layer was 1.29. Furthermore, the etching rate of the PtRu film serving as the absorber upper layer under the first etching conditions was 0.03 nm / sec. After etching of the PtRu film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, before removing the Hf film serving as the upper layer of the conductive film 2, the amount of film reduction of the Hf film serving as the absorber upper layer at the outer periphery was measured. As a result, the amount of film reduction of the Hf film serving as the conductive film 2 upper layer at the outer periphery after etching of the PtRu film serving as the absorber upper layer under the first etching conditions was 20% or less of the film thickness of the Hf film serving as the conductive film 2 upper layer at the outer periphery before etching of the PtRu film. Furthermore, the film thickness of the TaN film as the lower layer of the conductive film 2 after etching the PtRu film remained unchanged from the film thickness of the TaN film before etching the PtRu film. Furthermore, the film thickness of the TaN film after removing the Hf film as the upper layer of the conductive film 2 remained unchanged from the film thickness of the TaN film before removing the Hf film as the upper layer of the conductive film 2. In other words, even when a material that is difficult to etch is used for the absorber film 5, damage to the conductive film 2 caused by etching the absorber film 5 in the manufacturing process of the reflective mask 60 can be suppressed.

[0151] The reflective mask 60 of Example 8 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0152] Example 9 A conductive film 2 consisting of a RuNb film as a lower layer and an Al film as an upper layer was formed on the back surface 1b of a substrate 1 prepared in the same manner as in Example 1. Specifically, the substrate 1 was placed in a sputtering apparatus, and a RuNb film with a thickness of 60 nm was formed using a RuNb target and argon (Ar) as the sputtering gas. The composition ratio of the RuNb film was Ru:Nb = 80 atomic %:20 atomic %. Subsequently, an Al film with a thickness of 10 nm was formed using an Al target and xenon (Xe) as the sputtering gas.

[0153] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0154] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ).

[0155] Next, a reflective mask 60 was fabricated using the above-described reflective mask blank 40. First, an absorber film pattern 5a was formed on the protective film 4 in the same manner as in Example 1. Next, the Al film as the upper layer of the conductive film 2 was removed using an SPM cleaning solution. Furthermore, the resist pattern on the absorber film pattern 5a was removed to obtain a reflective mask 60. Note that the Al film as the upper layer of the conductive film 2 may be left as it is without being removed.

[0156] In Example 9, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the Al film serving as the conductive film 2 upper layer was 1.3. Furthermore, under the etching conditions for the first PtRu film, the etching rate of the PtRu film serving as the absorber upper layer was 0.03 nm / sec. After etching of the PtRu film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, before removing the Al film serving as the upper layer of the conductive film 2, the amount of film reduction of the Al film serving as the upper layer of the conductive film 2 at the outer periphery after etching of the PtRu film serving as the absorber upper layer under the etching conditions for the first PtRu film was 20% or less of the film thickness of the Al film serving as the upper layer of the conductive film 2 at the outer periphery before etching of the PtRu film. Furthermore, the film thickness of the RuNb film as the lower layer of the conductive film 2 after etching the PtRu film remained unchanged from the film thickness of the RuNb film before etching the PtRu film. Furthermore, the film thickness of the RuNb film after removing the Al film as the upper layer of the conductive film 2 remained unchanged from the film thickness of the RuNb film before removing the Al film as the upper layer of the conductive film 2. In other words, even when a material that is difficult to etch is used for the absorber film 5, damage to the conductive film 2 caused by etching the absorber film 5 in the manufacturing process of the reflective mask 60 could be suppressed.

[0157] The reflective mask 60 of Example 9 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0158] Example 10 Similar to Example 5, a conductive film 2 (70 nm thick) made of RuNb was formed on the rear surface 1b of a substrate 1 prepared in the same manner as in Example 1.

[0159] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0160] Next, using a DC magnetron sputtering apparatus, an absorber film 5 consisting of a stacked film of a TaBN film (thickness: 56 nm) as a lower absorber layer and a TaBO film (thickness: 14 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ). The TaBN film was deposited using a TaB target and a mixed gas of xenon and nitrogen. The composition ratio of the TaBN film was Ta:B:N = 75 atomic %:8 atomic %:17 atomic %. The TaBO film was deposited using a TaB target and a mixed gas of argon and oxygen. The composition ratio of the TaBO film was Ta:B:O = 40 atomic %:8 atomic %:52 atomic %.

[0161] Next, a reflective mask 60 was fabricated using the reflective mask blank 40. First, a resist pattern was formed on the reflective mask blank 40 in the same manner as in Example 1. Using this resist pattern as a mask, the absorber film 5 was etched to form an absorber film pattern 5a on the protective film 4. Specifically, CF ４ The TaBO film was etched using a mixture of Cl gas and He gas. ２ The TaBN film was etched using the gas. Furthermore, the resist pattern on the absorber film pattern 5a was removed, and a reflective mask 60 was obtained.

[0162] In Example 10, under the etching conditions (first etching conditions) for the TaBO film as the absorber upper layer, the etching selectivity of the TaBO film as the absorber upper layer to the conductive film 2 was 14.3. The etching rate of the TaBO film as the absorber upper layer under the first etching conditions was 0.39 nm / sec. The amount of film reduction in the thickness of the conductive film 2 at the outer periphery after etching of the TaBO film under the first etching conditions was 20% or less of the thickness of the conductive film 2 at the outer periphery before etching of the TaBO film. Under the etching conditions for the TaBN film as the absorber lower layer, the etching selectivity of the TaBN film as the absorber lower layer to the conductive film 2 was −21.5. That is, the thickness of the RuNb film as the conductive film 2 after etching of the TaBN film was greater than that before etching of the TaBN film. Furthermore, after etching the TaBO film and TaBN film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, the amount of film thickness reduction in the outer periphery of the conductive film 2 after etching the TaBO film and TaBN film was 20% or less of the film thickness in the outer periphery of the conductive film 2 before etching the TaBO film and TaBN film. In other words, even when a material that is difficult to etch is used for the absorber film 5, damage to the conductive film 2 caused by etching the absorber film 5 in the manufacturing process of the reflective mask 60 could be suppressed.

[0163] The reflective mask of Example 10 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0164] Example 11 A conductive film 2 consisting of a TaNb film as a lower layer and a CrN film as an upper layer was formed on the rear surface 1b of a substrate 1 prepared in the same manner as in Example 1, in the same manner as in Example 7.

[0165] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0166] Next, using a DC magnetron sputtering apparatus, an absorber film 5 consisting of a stacked film of a CrON film (thickness: 6 nm) as a lower absorber layer and an IrTaO film (thickness: 40 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ). The CrON film was deposited using a chromium target and a mixed gas of argon, oxygen, and nitrogen. The composition ratio of the CrON film was Cr:O:N = 75 atomic %:15 atomic %:10 atomic %. The IrTaO film was deposited using an IrTa target and a mixed gas of xenon and oxygen. The composition ratio of the IrTaO film was Ir:Ta:O = 52 atomic %:4 atomic %:44 atomic %.

[0167] Next, a reflective mask 60 was fabricated using the reflective mask blank 40. First, a resist pattern was formed on the reflective mask blank 40 in the same manner as in Example 1. This resist pattern was used as a mask, and CF ４ and O ２ The IrTaO film was grown using a mixed gas of ２ and O ２ The CrON film was etched with the mixed gas of the above to form an absorber film pattern 5a on the protective film 4. Furthermore, the resist pattern on the absorber film pattern 5a was removed to obtain a reflective mask 60.

[0168] In Example 11, under the etching conditions (first etching conditions) for the IrTaO film serving as the upper absorber layer, the etching selectivity of the IrTaO film serving as the upper absorber layer relative to the CrN film serving as the upper conductive film 2 was 37.5. Furthermore, the etching rate of the IrTaO film serving as the upper absorber layer under the first etching conditions was 0.15 nm / sec. After etching of the IrTaO film, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. Furthermore, after etching of the IrTaO film serving as the upper absorber layer under the first etching conditions, the amount of film thickness reduction at the outer periphery of the CrN film serving as the upper conductive film 2 was 20% or less of the film thickness at the outer periphery of the CrN film serving as the upper conductive film 2 before etching of the IrTaO film. Furthermore, the TaNb film serving as the lower conductive film 2 was not damaged, and the thickness of the TaNb film did not change before and after etching of the IrTaO film. That is, even when a material that is difficult to etch is used for the absorber film 5, damage to the conductive film 2 caused by etching the absorber film 5 during the manufacturing process of the reflective mask 60 can be suppressed.

[0169] The reflective mask 60 of Example 11 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask 60 was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0170] Example 12 A conductive film 2 consisting of a TaNb film as a lower layer and a CrN film as an upper layer was formed on the rear surface 1b of a substrate 1 prepared in the same manner as in Example 1, in the same manner as in Example 7.

[0171] Next, a multilayer reflective film 3 was formed on the first main surface 1t of the substrate 1 opposite to the conductive film 2 in the same manner as in Example 1. Furthermore, a protective film 4 (thickness: 2.5 nm) made of RuRhCrN was formed on the multilayer reflective film 3 to obtain a substrate with a multilayer reflective film. Specifically, a RuRhCr target and argon (Ar) and nitrogen (N) were used as sputtering gases. ２ ) mixed gas (flow ratio (%) Ar:N２ A RuRhCrN film was formed as the protective film 4 to a thickness of 3.5 nm by reactive sputtering using a mixture of Ru, Rh, Cr, and N (Ru:Rh:Cr:N=55:45). The composition ratio of the RuRhCrN film was 60 atomic %:30 atomic %:6 atomic %:4 atomic %.

[0172] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40 was obtained (see FIG. 4 ).

[0173] Next, a reflective mask was produced using the reflective mask blank 40. First, an absorber film pattern 5a was formed in the same manner as in Example 1. Next, in order to form a light-shielding region, a CF ４ The protective film 4 was etched with a mixed gas of Ar and He. Furthermore, the multilayer reflective film 3 was etched to form a light-shielding region. In this way, a reflective mask was obtained.

[0174] In Example 12, under the etching conditions for the PtRu film as the absorber upper layer, the etching selectivity of the PtRu film as the absorber upper layer relative to the CrN film as the conductive film 2 upper layer was the same as in Example 7. The etching rate of the PtRu film was the same as in Example 7. The amount of film thickness reduction at the outer periphery of the CrN film as the conductive film 2 upper layer after etching of the PtRu film was also the same as in Example 7. Furthermore, under the etching conditions for the protective film 4 (first etching conditions), the etching selectivity of the protective film 4 relative to the CrN film as the conductive film 2 upper layer was −0.88. The etching rate of the protective film 4 under the first etching conditions was 0.01 nm / sec. The thickness of the CrN film as the conductive film 2 upper layer after etching of the protective film 4 was greater than that before etching of the protective film 4. Therefore, under the first etching conditions, the amount of film thickness reduction at the outer periphery of the CrN film serving as the upper layer of the conductive film 2 after etching of the protective film 4 was 20% or less of the film thickness at the outer periphery of the CrN film serving as the upper layer of the conductive film 2 before etching of the protective film 4. Furthermore, the TaNb film serving as the lower layer of the conductive film 2 was not damaged, and the thickness of the TaNb film did not change before and after etching of the PtRu film. Furthermore, the thickness of the TaNb film did not change before and after etching of the protective film 4. Therefore, even after etching of the protective film 4, the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed. In other words, even when the absorber film 5 and the protective film 4 were made of materials that are difficult to etch, damage to the conductive film 2 caused by the etching during the manufacturing process of the reflective mask could be suppressed. Even after etching the multilayer reflective film 3, the amount of film thickness reduction at the outer periphery of the CrN film serving as the upper layer of the conductive film 2 was sufficiently small, at 20% or less of that before the etching, the TaNb film serving as the lower layer of the conductive film 2 was not damaged, and the outer periphery of the second main surface (rear surface) 1b of the substrate 1 was not exposed.

[0175] The reflective mask of Example 12 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the reflective mask was well supported by the electrostatic chuck via the conductive film 2, and high-precision pattern transfer was possible without causing any misalignment during exposure.

[0176] Comparative Example 1 A conductive film 2A made of TaN was formed on the rear surface 1b of a substrate 1 prepared in the same manner as in Example 1. More specifically, the substrate 1 was placed in a sputtering device, and a Ta target and argon (Ar) and nitrogen (N) were used as sputtering gases. ２ ) mixed gas (flow ratio (%) Ar:N ２ A TaN film having a thickness of 70 nm was formed by reactive sputtering using a TaN film having a composition ratio of Ta:N=74 atomic %:26 atomic %.

[0177] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2A in the same manner as in Example 1, to obtain a multilayer reflective film coated substrate.

[0178] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40A was obtained.

[0179] Next, a reflective mask 60A was fabricated using the reflective mask blank 40A. First, the reflective mask 60A was obtained in the same manner as in Example 1.

[0180] In Comparative Example 1, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the conductive film 2A was 0.07. Furthermore, the etching rate of the PtRu film serving as the absorber upper layer under the first etching conditions was 0.03 nm / sec. Furthermore, the amount of film thickness reduction at the outer periphery of the conductive film 2A after etching the PtRu film serving as the absorber upper layer under the first etching conditions was 80% of the film thickness at the outer periphery of the conductive film 2A before etching the PtRu film. That is, when a material that is difficult to etch was used for the absorber film 5, significant damage was caused to the conductive film 2A by etching the absorber film 5 during the manufacturing process of the reflective mask 60A.

[0181] The reflective mask 60A of Comparative Example 1 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, a transfer position shift occurred during exposure due to insufficient chucking force of the electrostatic chuck, and high-precision pattern transfer was not possible.

[0182] Comparative Example 2: A conductive film 2B made of CrTa was formed on the back surface 1b of a substrate 1 prepared in the same manner as in Example 1. Specifically, the substrate 1 was placed in a sputtering device, and a CrTa film with a thickness of 70 nm was formed using a CrTa target and argon (Ar) as the sputtering gas. The composition ratio of the CrTa film was Cr:Ta = 30 atomic %: 70 atomic %.

[0183] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2B in the same manner as in Example 1, to obtain a multilayer reflective film coated substrate.

[0184] Subsequently, an absorber film 5 consisting of a laminated film of a CrN film (film thickness: 4 nm) as a lower absorber layer and a PtRu film (film thickness: 30 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 1. In this manner, a reflective mask blank 40B was obtained.

[0185] Next, a reflective mask 60B was fabricated using the reflective mask blank 40B. First, the reflective mask 60B was obtained in the same manner as in Example 1.

[0186] In Comparative Example 2, under the etching conditions (first etching conditions) for the PtRu film serving as the absorber upper layer, the etching selectivity of the PtRu film serving as the absorber upper layer relative to the conductive film 2B was 0.55. Furthermore, the etching rate of the PtRu film serving as the absorber upper layer under the first etching conditions was 0.03 nm / sec. Furthermore, the amount of film thickness reduction at the outer periphery of the conductive film 2B after etching the PtRu film serving as the absorber upper layer under the first etching conditions was 50% of the film thickness at the outer periphery of the conductive film 2B before etching the PtRu film. That is, when a material that is difficult to etch was used for the absorber film 5, significant damage was caused to the conductive film 2B by etching the absorber film 5 in the manufacturing process of the reflective mask 60B.

[0187] The reflective mask 60B of Comparative Example 2 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, a transfer position shift occurred during exposure due to insufficient chucking force of the electrostatic chuck, and high-precision pattern transfer was not possible.

[0188] Comparative Example 3: A conductive film 2C made of TaB was formed on the back surface 1b of a substrate 1 prepared in the same manner as in Example 1. Specifically, the substrate 1 was placed in a sputtering apparatus, and a TaB film with a thickness of 70 nm was formed using a TaB target and argon (Ar) as the sputtering gas. The composition ratio of the TaB film was Ta:B = 80 atomic %: 20 atomic %.

[0189] Next, a multilayer reflective film 3 and a protective film 4 were formed in this order on the first main surface 1t of the substrate 1 opposite to the conductive film 2C in the same manner as in Example 1, to obtain a multilayer reflective film coated substrate.

[0190] Subsequently, an absorber film 5 consisting of a laminated film of a TaBN film (film thickness: 56 nm) as a lower absorber layer and a TaBO film (film thickness: 14 nm) as an upper absorber layer was formed on the protective film 4 of the multilayer reflective film-coated substrate using a DC magnetron sputtering apparatus in the same manner as in Example 10. In this manner, a reflective mask blank 40C was obtained.

[0191] Next, a reflective mask 60C was fabricated using the reflective mask blank 40C. First, the reflective mask 60C was obtained in the same manner as in Example 10.

[0192] In Comparative Example 3, under the etching conditions (first etching conditions) for the TaBO film as the absorber upper layer, the etching selectivity of the TaBO film as the absorber upper layer to the conductive film 2C was 0.69. The etching rate of the TaBO film as the absorber upper layer under the first etching conditions was 0.39 nm / sec. The amount of film thickness reduction at the outer periphery of the conductive film 2C after etching the TaBO film as the absorber upper layer under the first etching conditions was 40% of the film thickness at the outer periphery of the conductive film 2C before etching the TaBO film. That is, when a material that is difficult to etch was used for the absorber film 5, the conductive film 2C suffered significant damage due to etching of the absorber film 5 in the manufacturing process of the reflective mask 60C.

[0193] The reflective mask 60C of Comparative Example 3 thus obtained was set in an exposure apparatus, and a pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, a transfer position shift occurred during exposure due to insufficient chucking force of the electrostatic chuck, and high-precision pattern transfer was not possible.

[0194] REFERENCE SIGNS LIST 1 substrate 1t first main surface 1b second main surface 2 conductive film 3 multilayer reflective film 4 protective film 5 absorber film 5a absorber film pattern 6 etching mask film 7 first film 10 substrate with conductive film 20 substrate with multilayer reflective film 30, 40, 50 reflective mask blank 60 reflective mask 70 substrate with conductive film

Claims

1. A substrate with a conductive film, comprising: a substrate having a first main surface and a second main surface opposite the first main surface; a first film formed on the first main surface and having a first film composition; and a conductive film formed on the second main surface and having a second film composition, wherein, under first etching conditions used to etch the first film, the etching selectivity of the first film composition to the second film composition is 0.8 or more or less than 0.

2. A substrate with a conductive film, comprising: a substrate having a first main surface and a second main surface opposite the first main surface; a first film formed on the first main surface; and a conductive film formed on the second main surface and having a second film, wherein, under first etching conditions used to etch the first film, the etching selectivity of the first film to the second film is 0.8 or more or less than 0.

3. A substrate with a conductive film as described in claim 1 or 2, characterized in that when the first film is etched under the first etching conditions, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the first film is 20% or less of the film thickness at the outer periphery of the conductive film before etching of the first film.

4. The substrate with a conductive film according to claim 1 or 2, wherein the etching rate of said first film under said first etching conditions is greater than 0 and not more than 0.5 nm / sec.

5. The substrate with a conductive film according to claim 1 or 2, wherein the conductive film is a single layer film.

6. The substrate with a conductive film according to claim 1, characterized in that the conductive film has an upper layer farthest from the second main surface of the substrate and a lower layer formed between the upper layer and the second main surface, and the upper layer has the second film composition.

7. The substrate with a conductive film described in claim 2, characterized in that the conductive film has an upper layer that is farthest from the second main surface of the substrate and a lower layer formed between the upper layer and the second main surface, and the upper layer is the second film.

8. The substrate with a conductive film according to claim 1 or 2, wherein the conductive film contains at least one of hafnium, niobium, ruthenium, iridium, and rhodium.

9. A substrate with a multilayer reflective film, comprising, on the first main surface of the substrate with a conductive film according to claim 1 or 2, a multilayer reflective film including alternatingly stacked high refractive index layers and low refractive index layers, or a protective film formed on the multilayer reflective film and the multilayer reflective film, wherein the first film is the multilayer reflective film or the protective film.

10. A mask blank comprising a multilayer reflective film including alternating high refractive index layers and low refractive index layers on the first main surface of the conductive film-coated substrate according to claim 1 or 2, and the first film being formed on the multilayer reflective film.

11. A mask blank as described in claim 10, characterized in that when the first film is etched under the first etching conditions, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the first film is 20% or less of the film thickness at the outer periphery of the conductive film before etching of the first film.

12. The mask blank according to claim 10, wherein the etching rate of said first film under said first etching conditions is greater than 0 and equal to or less than 0.5 nm / sec.

13. The mask blank according to claim 10, wherein the conductive film is a single layer film.

14. A mask blank comprising a multilayer reflective film including alternating high refractive index layers and low refractive index layers on the first main surface of the conductive film-coated substrate according to claim 6, wherein the first film is formed on the multilayer reflective film.

15. A mask blank comprising a multilayer reflective film including alternating high refractive index layers and low refractive index layers on the first main surface of the conductive film-coated substrate according to claim 7, wherein the first film is formed on the multilayer reflective film.

16. The mask blank according to claim 10, wherein the conductive film contains at least one of hafnium, niobium, ruthenium, iridium, and rhodium.

17. The mask blank according to claim 10, characterized in that it has an absorber film that absorbs EUV light on the multilayer reflective film, or an etching mask film provided on the absorber film and the absorber film, and the first film is the absorber film or the etching mask film.

18. A reflective mask comprising a multilayer reflective film including alternating high refractive index layers and low refractive index layers stacked on the first main surface of the conductive film-coated substrate described in claim 1 or 2, wherein the first film is formed on the multilayer reflective film and has a transfer pattern.

19. The reflective mask described in claim 18, characterized in that when the first film is etched under the first etching conditions, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the first film is 20% or less of the film thickness at the outer periphery of the conductive film before etching of the first film.

20. The reflective mask according to claim 18, wherein the etching rate of said first film under said first etching conditions is greater than 0 and equal to or less than 0.5 nm / sec.

21. The reflective mask according to claim 18, wherein the conductive film is a single layer film.

22. A reflective mask comprising a multilayer reflective film including alternating high refractive index layers and low refractive index layers stacked on the first main surface of the conductive film-coated substrate according to claim 6, wherein the first film is formed on the multilayer reflective film and has a transfer pattern.

23. A reflective mask comprising a multilayer reflective film including alternating high refractive index layers and low refractive index layers stacked on the first main surface of the conductive film-coated substrate described in claim 7, wherein the first film is formed on the multilayer reflective film and has a transfer pattern.

24. The reflective mask according to claim 18, wherein the conductive film contains at least one of hafnium, niobium, ruthenium, iridium, and rhodium.

25. The reflective mask according to claim 18, further comprising an absorber film that absorbs EUV light on the multilayer reflective film, and the first film is the absorber film.

26. A method for manufacturing a semiconductor device, comprising the step of transferring the transfer pattern onto a transfer target by exposure using the reflective mask according to claim 18.

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