Mask blank and mask

Abstract

Provided is a mask blank in which damage to a conductive film caused by etching of an absorber film or the like is reduced even when a material with low etchability is used for the absorber film or the like.　This mask blank 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 a conductive film formed on the second main surface. The conductive film contains a metal M1. When each of a pressure Pch and a temperature Tch is used to etch the first film with a halogen, the vapor pressure Pm of a halogen compound composed of the halogen and the metal M1 is lower than the pressure Pch at the temperature Tch.

Description

Mask blanks and masks

[0001] This invention relates to mask blanks and masks.

[0002] Generally, in the manufacturing process of semiconductor devices, fine patterns are formed using photolithography. This process typically involves the use of multiple transfer masks, also known as photomasks. These transfer masks generally consist of a glass substrate with a fine pattern made of a thin metal film or similar material. Electron beam lithography is used in the manufacturing of these transfer masks.

[0003] In the manufacture of transfer masks by electron beam lithography, a mask blank having a thin film (e.g., a light-shielding film) for forming a transfer pattern (mask pattern) on a substrate such as a glass substrate is used. The manufacture of a transfer mask using this mask blank is carried out through a drawing step in which a desired pattern is drawn on a resist film formed on the mask blank, a developing step in which the resist film is developed after drawing to form a desired resist pattern, an etching step in which the thin film is etched using this resist pattern as a mask, and a step in which the remaining resist pattern is removed. In the developing step, a developer is supplied to the resist film after the drawing step to dissolve the resist film in the parts soluble in the developer and form a resist pattern. In the etching step, this resist pattern is used as a mask to remove the thin film that is exposed and where no resist pattern has been formed, by dry etching or wet etching. This forms the desired mask pattern on the substrate. In this way, a transfer mask is completed.

[0004] In addition to the conventional binary type mask, which has a light-shielding film pattern made of chromium-based material on a substrate, phase-shift type masks are also known as transfer masks.

[0005] Furthermore, in recent years, the semiconductor industry has seen an increase in the integration of semiconductor devices, requiring finer patterns that exceed the transfer limits of conventional ultraviolet light lithography methods. To enable the formation of such fine patterns, there is EUV lithography, an exposure technique that uses extreme ultraviolet (UUV) light. Hereinafter, extreme ultraviolet light will be referred to as EUV light. Here, EUV light refers to light in the wavelength range of the soft X-ray region or the vacuum ultraviolet region, more specifically, light with a wavelength of about 0.2 to 100 nm. In this specification, EUV light includes light with a wavelength of 13.5 nm, more specifically light with a wavelength of 13 nm to 14 nm, and more specifically, light with a wavelength of 13.5 nm. In this specification, light includes not only visible light but also electromagnetic waves. Reflective masks are used as masks in this EUV lithography. Such a reflective mask is formed on a substrate and comprises a multilayer reflective film that reflects EUV light, which is the exposure light, and an absorber film that is formed in a pattern on the multilayer reflective film and absorbs EUV light.

[0006] A reflective mask is supported, for example, by an electrostatic chuck in an exposure apparatus when transferring a pattern onto a semiconductor substrate. On the other hand, the substrate used for the reflective mask blank or reflective mask is made of an insulating glass substrate or the like. For this reason, a conductive film (backside conductive film) is formed on the back surface of the substrate of the reflective mask blank or reflective mask. As a prior art, for example, Patent Document 1 discloses a mask substrate having a backside coating (conductive film) of a material with a higher dielectric constant than the substrate, such as silicon, molybdenum, chromium, chromium oxynitride, or TaSi.

[0007] Japanese Patent Publication No. 2003-501823, International Publication No. 2023 / 171582

[0008] In recent years, absorber films made of materials with high refractive indices and low extinction coefficients for EUV light have been sought to improve pattern resolution, throughput, and / or reduce the so-called shadowing effect. However, such materials are so-called difficult to etch and therefore have low etching rates. For example, Patent Document 2 discloses an absorber film using a difficult-to-etch material. Furthermore, the use of difficult-to-etch materials is increasing for protective films formed between multilayer reflective films and absorber films. Consequently, etching such difficult-to-etch materials requires longer etching times than conventional materials.

[0009] The conductive film is formed on the main surface (back side) of the substrate opposite to the main surface where the absorber film is formed. Therefore, when etching the absorber film, the conductive film is almost completely shielded. As a result, even if some of the gas used to etch the absorber film seeps into the back side, if the absorber film is made of conventional materials, the conductive film does not suffer significant etching damage. However, the inventors' research has shown that when a difficult-to-etch material is used for the absorber film (or the etching mask film, protective film, etc. on the absorber film), even if the conductive film is almost completely shielded, the etching gas that seeps into the back side can damage the conductive film (especially near the outer edge). Damage to the conductive film also affects the substrate adsorption force by the electrostatic chuck, the quality of the reflective mask, and / or the pattern transfer accuracy.

[0010] Therefore, the present invention has been made in view of these problems. One object of the present invention is to provide a mask blank, such as a reflective mask blank, that minimizes damage to the conductive film due to etching of the absorber film, even when a difficult-to-etch material is used for the absorber film, etc. Another object is to provide a mask using the above mask blank.

[0011] The present inventors have diligently continued their research to solve the conventional problems and have completed the following invention. (Configuration 1) A mask blank comprising 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 a conductive film formed on the second main surface, wherein the conductive film contains a metal M1, and when pressure Pch and temperature Tch are used to etch the first film with a halogen, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower than the pressure Pch at temperature Tch.

[0012] (Configuration 2) The mask blank according to Configuration 1, characterized in that the halogen is fluorine or chlorine. (Configuration 3) The mask blank according to Configuration 1 or 2, characterized in that the metal M1 is at least one selected from palladium, iridium, rhodium, zirconium, and yttrium.

[0013] (Configuration 4) The mask blank according to any one of Configurations 1 to 3, characterized in that the conductive film contains tantalum or chromium in addition to the metal M1. (Configuration 5) The mask blank according to any one of Configurations 1 to 4, characterized in that the conductive film is formed by a single layer film containing 3 atomic percent or more of the metal M1.

[0014] (Configuration 6) The mask blank according to any one of Configurations 1 to 4, characterized in that the conductive film is formed by two or more layers, each including a layer L1 containing 3 atomic percent or more of the metal M1. (Configuration 7) Primary ion species is Cs ＋ When the conductive film was analyzed in an arbitrary 124 μm square region within a 5 cm square including the center of the substrate by dynamic secondary ion mass spectrometry under the conditions of a primary acceleration voltage of 3.0 kV and a primary ion current of 25 nA, the conductive film was found to be 1.0 × 10⁻¹⁶. ２ A mask blank according to any one of configurations 1 to 6, characterized by having a secondary ion strength of hydrogen of cps or higher.

[0015] (Configuration 8) The mask blank according to any one of Configurations 1 to 7, characterized in that the conductive film is formed in contact with the second main surface. (Configuration 9) The mask blank according to any one of Configurations 1 to 5, 7, or 8, characterized in that the conductive film consists of a single layer or a single layer including a surface oxidation region on the outermost surface.

[0016] (Configuration 10) The mask blank according to any one of Configurations 1 to 4 or any one of Configurations 6 to 8, characterized in that the conductive film comprises a layer L1 containing the metal M1 and a layer L2 containing a metal M2 different from the metal M1. (Configuration 11) The mask blank according to Configuration 10, characterized in that the metal M2 is tantalum or chromium.

[0017] (Configuration 12) The mask blank according to Configuration 10 or 11, characterized in that the layer L1 is formed on the layer L2. (Configuration 13) The mask blank according to Configuration 10 or 11, characterized in that the layer L2 is formed on the layer L1.

[0018] (Configuration 14) A mask blank according to any one of Configurations 1 to 13, characterized in that the first film contains at least one of ruthenium, platinum, iridium, rhodium, and silicon. (Configuration 15) A mask blank according to any one of Configurations 1 to 14, characterized in that, at the temperature Tch and the pressure Pch, the etching rate of the first film when the first film is etched with the halogen is 0.5 nm / second or less.

[0019] (Configuration 16) A mask comprising 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 a conductive film formed on the second main surface, wherein the conductive film contains a metal M1, and when pressure Pch and temperature Tch are used to etch the first film with a halogen, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower than the pressure Pch at temperature Tch.

[0020] (Configuration 17) The mask according to Configuration 16, characterized in that the halogen is fluorine or chlorine. (Configuration 18) The mask according to Configuration 16 or 17, characterized in that the metal M1 is at least one selected from palladium, iridium, rhodium, zirconium, and yttrium.

[0021] (Configuration 19) The mask according to any one of Configurations 16 to 18, characterized in that the conductive film contains tantalum or chromium in addition to the metal M1. (Configuration 20) The mask according to any one of Configurations 16 to 19, characterized in that the conductive film is formed by a single layer film containing 3 atomic percent or more of the metal M1.

[0022] (Configuration 21) The mask according to any one of Configurations 16 to 19, characterized in that the conductive film is formed of two or more layers, each including a layer L1 containing 3 atomic percent or more of the metal M1. (Configuration 22) Primary ion species is Cs ＋ When the conductive film was analyzed in an arbitrary 124 μm square region within a 5 cm square including the center of the substrate by dynamic secondary ion mass spectrometry under the conditions of a primary acceleration voltage of 3.0 kV and a primary ion current of 25 nA, the conductive film was found to be 1.0 × 10⁻¹⁶. ２ A mask according to any one of configurations 16 to 21, characterized by having a secondary ion strength of hydrogen of cps or higher.

[0023] (Configuration 23) The mask according to any one of Configurations 16 to 22, characterized in that the conductive film is formed in contact with the second main surface. (Configuration 24) The mask according to any one of Configurations 16 to 20, 22, or 23, characterized in that the conductive film consists of a single layer or a single layer including a surface oxidation region on the outermost surface.

[0024] (Configuration 25) The mask according to any one of Configurations 16 to 19 or any one of Configurations 21 to 23, characterized in that the conductive film comprises a layer L1 containing the metal M1 and a layer L2 containing a metal M2 different from the metal M1. (Configuration 26) The mask according to Configuration 25, characterized in that the metal M2 is tantalum or chromium.

[0025] (Configuration 27) The mask according to configuration 25 or 26, characterized in that the layer L1 is formed on the layer L2. (Configuration 28) The mask according to configuration 25 or 26, characterized in that the layer L2 is formed on the layer L1.

[0026] (Configuration 29) The mask according to any one of Configurations 16 to 28, characterized in that the first film comprises at least one of ruthenium, platinum, iridium, rhodium, and silicon. (Configuration 30) The mask according to any one of Configurations 16 to 29, characterized in that, at the temperature Tch and the pressure Pch, the etching rate of the first film when the first film is etched with the halogen is 0.5 nm / second or less.

[0027] According to the present invention, even when difficult-to-etch materials are used for absorber films, etc., it is possible to provide mask blanks such as reflective mask blanks that cause less damage to the conductive film due to etching of absorber films, etc. Furthermore, according to the present invention, it is possible to provide masks using the above-mentioned mask blanks. Masks using the above-mentioned mask blanks cause less damage to the conductive film, and therefore do not affect the substrate adsorption force by electrostatic chucks, the quality of reflective masks, or the pattern transfer accuracy.

[0028] This is a cross-sectional view showing one embodiment of the mask blank of the present invention. This is a cross-sectional view showing one embodiment of a substrate with a multilayer reflective film. This is a cross-sectional view showing one embodiment of a reflective mask blank. This is a cross-sectional view showing another embodiment of a reflective mask blank. This is a cross-sectional view showing yet another embodiment of a reflective mask blank. This is a cross-sectional view showing one embodiment of a reflective mask. This is a cross-sectional view showing another embodiment of the mask blank of the present invention. This figure shows an example of the vapor pressure curve of a halogen compound of metal M1 contained in a conductive film.

[0029] Embodiments of the present invention will be described in detail below. [Mask Blank] First, the mask blank of the present invention will be described. The mask blank of the present invention comprises 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 a conductive film formed on the second main surface. The conductive film contains a metal M1. When pressure Pch and temperature Tch are used to etch the first film with a halogen, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower than the pressure Pch at temperature Tch.

[0030] Figure 1 is a cross-sectional view showing one embodiment of the mask blank of the present invention. As shown in Figure 1, the mask blank 10 of this embodiment comprises a substrate 1 having a first main surface (the upper surface of the substrate 1 in Figure 1) and a second main surface facing the first main surface (the lower surface of the substrate 1 in Figure 1), a first film 7 formed on the first main surface, and a conductive film 2 formed on the second main surface. The multilayer reflective film substrate 20 described later is a type of mask blank 10 because it includes the conductive film 2 on the second main surface of the substrate 1. Furthermore, all of the mask blanks described later (reflective mask blanks 30, 40, 50) are also a type of mask blank 10 because they include the conductive film 2 on the second main surface of the substrate 1.

[0031] The substrate 1 has two opposing main surfaces (the first main surface and the second main surface) and an end face. When the mask blank of the present invention is used, for example, as a reflective mask blank for EUV exposure, a glass substrate is preferred for the substrate 1. In particular, in order to prevent distortion of the pattern due to heat during exposure, the substrate 1 is preferably 0 ± 1.0 × 10 －７ Within the range of / ℃, more preferably 0 ± 0.3 × 10 －７ A glass substrate having a low thermal expansion coefficient within the range of / °C is used. Examples of materials having a low thermal expansion coefficient within this range include SiO ２ -TiO ２ Glass-based materials, multi-component glass-ceramics, etc., can be used.

[0032] The main surface (the first main surface) of the above glass substrate on which a transfer pattern is formed is surface-processed to have high flatness at least from the viewpoint of improving pattern transfer accuracy and positional accuracy. In the case of EUV exposure, the flatness is preferably 0.1 μm or less, particularly preferably 0.05 μm or less, in a 142 mm × 142 mm region of the main surface where the transfer pattern of the glass substrate is formed. In this specification, flatness is a value representing the warpage (amount of deformation) of a surface indicated by TIR (Total Indicated Reading). This value is the absolute value of the height difference between the highest position of the surface of the substrate 1 above the focal plane and the lowest position of the surface of the substrate 1 below the focal plane, where the focal plane is a plane defined by the least squares method with reference to the surface of the substrate 1.

[0033] Further, in the case of EUV exposure, as described above, the glass substrate is SiO ２ -TiO ２ -based glass and other materials having a low coefficient of thermal expansion are preferably used. For the purpose of reducing the surface roughness of the glass substrate or reducing defects on the glass substrate surface, an underlayer may be formed on the main surface (the first main surface) of the glass substrate on which the transfer pattern is formed, if necessary. Such an underlayer material does not need to be translucent to exposure light. As the material for the underlayer, a material that can provide high smoothness when the surface of the underlayer is precisely polished and achieve good defect quality is preferably selected. For example, Si or silicon compounds containing Si (e.g., SiO ２ , SiON, etc.) can provide high smoothness when precisely polished and have good defect quality. Therefore, the above Si or silicon compound containing Si is preferably used as the material for the underlayer. Si is particularly preferable as the material for the underlayer. By using such an underlayer, high smoothness of, for example, 0.1 nm or less in terms of root mean square roughness (Rq) can be achieved as the surface roughness of the glass substrate.

[0034] The surface of the substrate layer is preferably precisely polished to achieve the smoothness required for a substrate used as a reflective mask blank. The surface of the substrate layer is precisely polished to a root mean square roughness (Rq) of preferably 0.15 nm or less, and particularly preferably 0.1 nm or less. Furthermore, considering the effect on the surface of the multilayer reflective film formed on the substrate layer, the surface of the substrate layer is precisely polished so that the relationship between root mean square roughness (Rq) and maximum height (Rmax) is preferably Rmax / Rq of 2 to 10, and particularly preferably 2 to 8. The thickness of the substrate layer is preferably in the range of, for example, 10 nm to 300 nm.

[0035] The first film 7 described above is formed on the first main surface of the substrate 1. This first film 7 can be any film that is patterned. This first film 7 can be, for example, an absorber film in a reflective mask blank described later, or an etching mask film provided on the absorber film. If an etching stopper film that is patterned is provided, the first film 7 may also be the etching stopper film.

[0036] Furthermore, in a substrate with a multilayer reflective film comprising a multilayer reflective film including alternately stacked high-refractive-index layers and low-refractive-index layers on the first main surface, or the multilayer reflective film and a protective film formed on the multilayer reflective film, the first film 7 can be a multilayer reflective film or a protective film. For example, in order to form a black border of a reflective mask, the multilayer reflective film, or the multilayer reflective film and protective film, may be etched to form a pattern corresponding to the black border. In such cases, the effects of the present invention can be obtained well. The black border referred to here is a region provided on the outer periphery of a region including a transfer pattern so that the transfer pattern of the reflective mask is exposed. The black border is formed to prevent exposure light from leaking into a region adjacent to the transfer region on the semiconductor substrate where the pattern is transferred when a pattern is transferred using a reflective mask.

[0037] Furthermore, in the case of binary-type masks or phase-shift-type masks used to manufacture transfer masks for conventional ultraviolet light lithography, the first film 7 can be a film for forming a transfer pattern formed on the first main surface of the substrate.

[0038] Therefore, the material of the first film 7 is not particularly limited, as long as it does not impair the effects of the present invention. Examples of materials for the first film 7 include materials 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). Furthermore, the material of the first film 7 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. In particular, the effects of the present invention are further enhanced when a material that is difficult to etch is used as the material for the first film 7. Examples of materials that are difficult to etch include materials containing at least one of ruthenium (Ru), platinum (Pt), iridium (Ir), rhodium (Rh), and silicon (Si).

[0039] The conductive film 2 is formed on the second main surface of the substrate 1, and the conductive film 2 contains a metal M1. Here, it is preferable that the conductive film 2 is formed in contact with the second main surface of the substrate 1. The metal M1 is preferably at least one selected from, for example, palladium (Pd), iridium (Ir), rhodium (Rh), zirconium (Zr), and yttrium (Y). In addition to the metal M1, the conductive film 2 may also contain, for example, tantalum (Ta) or chromium (Cr).

[0040] The conductive film 2 may be a single layer film consisting of a single layer containing the metal M1, or it may be a laminated film of two or more layers including a layer L1 containing the metal M1.

[0041] If the conductive film 2 is a single layer film consisting of a single layer containing the metal M1, it may also be a single layer film consisting of a single layer including a surface oxidation region at the outermost surface furthest from the substrate 1.

[0042] Furthermore, if the conductive film 2 is a laminated film of two or more layers including a layer L1 containing the metal M1, for example, it can be a laminated film having a layer L1 containing the metal M1 and a layer L2 containing a metal M2 different from the metal M1. The metal M2 is, for example, tantalum or chromium. In this case, layer L1 may be formed on top of layer L2, or layer L2 may be formed on top of layer L1. That is, the conductive film 2 may be a laminated film in which the uppermost layer furthest from the substrate 1 is layer L1, and the lower layer formed between the upper layer and the second main surface of the substrate 1 is layer L2. Alternatively, the conductive film 2 may be a laminated film in which the uppermost layer furthest from the substrate 1 is layer L2, and the lower layer formed between the upper layer and the second main surface of the substrate 1 is layer L1.

[0043] Furthermore, if the conductive film 2 is a multilayer film including such an upper layer and a lower layer, an intermediate layer may be present between the upper layer and the lower layer. The intermediate layer may consist of one or more layers. The lower layer and the intermediate layer may be collectively referred to as the lower layer. In the following, when simply referred to as the "lower layer," unless otherwise specified, this includes configurations where the lower layer and the intermediate layer are collectively referred to as the lower layer. That is, the lower layer may contain multiple layers.

[0044] In this invention, as described above, when pressure Pch and temperature Tch are used to etch the first film 7 with a halogen, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower at temperature Tch than at pressure Pch. This makes it possible to suppress damage to the conductive film 2 caused by etching the first film 7, even when, for example, a difficult-to-etch material is used for the first film 7. Note that pressure Pch and temperature Tch are the pressure and temperature inside the chamber where the etching of the first film 7 is performed.

[0045] As described above, if the conductive film 2 is a laminated film having, for example, a layer L1 containing the metal M1 and a layer L2 containing a metal M2 different from the metal M1, the following effects are obtained. For example, reflective masks are usually inspected after they are manufactured. In this inspection, the quality of the mask may be determined by irradiating the second main surface of the substrate 1 on which the conductive film 2 is formed with light of a specific wavelength and detecting the reflected light from the conductive film 2. If the outer periphery of the second main surface of the substrate 1 is exposed due to damage to the conductive film 2 caused by etching of the first film 7, sufficient reflected light cannot be obtained at the outer periphery during the inspection. As a result, a reflective mask with the outer periphery of the second main surface exposed may be judged as a defective product. By having a layer L1 containing the metal M1 in the conductive film 2, even if other layers of the conductive film 2 (for example, layer L2) are damaged by etching of the first film 7, the exposure of the outer periphery of the second main surface of the substrate 1 can be suppressed or reduced. The above effects can be obtained more effectively when the conductive film 2 is a laminated film comprising the upper layer L2, which is the uppermost layer furthest from the substrate 1, and the lower layer L1, which is formed between the upper layer and the second main surface of the substrate 1. When the lower layer of the conductive film 2 is the layer L1 containing the metal M1, in order to suppress or reduce the exposure of the outer periphery of the second main surface, it is preferable that the lower layer (layer L1) covers at least the outer periphery of the second main surface, and it is particularly preferable that it covers the entire surface of the second main surface so that the second main surface is not exposed.

[0046] If 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 after etching of the first film 7 as needed. When removing the upper layer, it is preferable that the upper layer can be easily removed with a cleaning solution or the like. When removing the upper layer by cleaning, for example, the upper layer can be removed using 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 water (an aqueous solution of ammonia water and hydrogen peroxide). The upper layer does not necessarily need to be removed.

[0047] Furthermore, when the upper layer of the conductive film 2 is a layer L1 containing the metal M1, in order to suppress or reduce damage to the vicinity of the outer periphery of the conductive film 2 due to etching of the first film 7, it is preferable that the upper layer (layer L1) covers at least the sides of the lower layer, more preferably the outer periphery of the lower layer, and particularly preferably the entire surface of the lower layer so that the lower layer is not exposed. In order to form the upper layer such that the upper layer (layer L1) covers at least the sides or outer periphery of the lower layer, the following steps can be taken. First, the lower layer is formed on the second main surface of the substrate 1. Then, the upper layer can be formed while shielding the areas other than the sides or outer periphery of the lower layer so that only the sides or outer periphery of the lower layer are exposed.

[0048] A film provided on a substrate 1, including the conductive film 2, has a shape in which, in a cross-sectional view, the film thickness gradually decreases as it approaches the edge of the film in the vicinity of the edge. 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 this specification, 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 that edge in a cross-sectional view. When 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 toward the 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. If the main surface of the substrate 1 is rectangular, length L can be the distance between two opposing long sides of the lower layer in a top view. More specifically, the outer periphery of the lower layer can extend within 2.0 mm from one edge of the lower layer toward the opposing edge. The conductive film 2, including the underlying layer, is often formed to extend to the edge of the second main surface of the substrate 1. Therefore, the outer periphery of the underlying layer can extend, for example, within 2.0 mm from one edge of the second main surface of the substrate 1 towards the other opposing edge of the second main surface. The outer periphery of the conductive film 2 and the outer periphery of layers other than the underlying layer included in the conductive film 2 can be defined in the same manner as described above.

[0049] As described above, the conductive film 2 contains metal M1. Metal M1 is not particularly limited as long as it does not impair the effects of the present invention, but it is preferably at least one selected from, for example, palladium (Pd), iridium (Ir), rhodium (Rh), zirconium (Zr), and yttrium (Y). In addition, the conductive film 2 may also contain, for example, tantalum (Ta) or chromium (Cr) in addition to metal M1. Furthermore, the conductive film 2 may further contain at least one element selected from oxygen (O), nitrogen (N), carbon (C), boron (B), hydrogen (H), and noble gases in addition to these elements.

[0050] Furthermore, during pattern transfer (under a hydrogen atmosphere), hydrogen plasma generated in the exposure environment may penetrate the conductive film, raising concerns that this could deform the mask substrate. While this does not necessarily result in deformation of the mask substrate, if deformation does occur, it could cause misalignment during pattern transfer by exposure. Therefore, it is preferable to pre-contain hydrogen in the conductive film.

[0051] In this invention, the primary ion species is Cs ＋ When the conductive film 2 was analyzed in an arbitrary 124 μm square region within a 5 cm square including the center of the substrate 1 by dynamic secondary ion mass spectrometry under the conditions of a primary acceleration voltage of 3.0 kV and a primary ion current of 25 nA, the conductive film 2 was found to be 1.0 × 10⁻¹⁴. ２ It is preferable to have a hydrogen secondary ion strength of cps or higher. When the conductive film 2 is analyzed by this analytical method, the hydrogen secondary ion strength detected is 1.0 × 10⁻¹⁰. ２ By pre-containing hydrogen in a range of cps or higher in the conductive film 2, it is possible to suppress the penetration of hydrogen generated in the exposure environment into the conductive film during mask exposure.

[0052] When the mask is exposed to the exposure environment, hydrogen is thought to be absorbed from the outermost surface and / or sides of the conductive film 2. Therefore, the secondary ion intensity of hydrogen detected by the above analytical method is 1.0 × 10⁻¹⁶ in at least the surface region or sides of the conductive film 2. ２ It is preferable that the solution contains hydrogen in a range of cps or higher. This makes it possible to suppress deformation of the mask substrate due to stress changes in the conductive film 2 on the back surface, even when a mask manufactured using the mask blank of the present invention is exposed to an exposure environment.

[0053] Furthermore, it is preferable that the conductive film 2 contains hydrogen not only in the surface and side regions but also in other regions, and it is more preferable that it contains hydrogen throughout the film thickness direction. If the conductive film 2 is a laminated film, it is preferable that both the lower layer and the upper layer contain hydrogen. This further suppresses deformation of the mask substrate due to stress changes in the conductive film 2.

[0054] One method for introducing hydrogen into the conductive film 2 is to include hydrogen in the sputtering gas used during the deposition of the conductive film 2, thereby incorporating hydrogen into the deposited conductive film 2. Alternatively, hydrogen can be incorporated into the conductive film 2 by irradiating it with hydrogen plasma after deposition.

[0055] The secondary ion strength of hydrogen mentioned above is 1.0 × 10⁻⁶. ５ It is preferable that it be less than or equal to cps, and 1.0 × 10 ４ It is more preferable that the value be less than or equal to cps. This allows the stress of the conductive film 2 to be adjusted to an appropriate range. The unit of secondary ion strength, cps, stands for counts per sec and represents the intensity of secondary ions detected per unit time. In this specification, the unit of secondary ion strength of hydrogen is cps unless otherwise specified.

[0056] On the other hand, the conductive film 2 does not necessarily have to contain hydrogen. Among the metals M1, for example, palladium (Pd), iridium (Ir), and rhodium (Rh) do not readily incorporate hydrogen. Therefore, it is particularly preferable that the conductive film 2 contains at least one selected from palladium (Pd), iridium (Ir), and rhodium (Rh).

[0057] Furthermore, when a chlorine-based gas is used to etch the first film 7, it is preferable that the conductive film 2 contains at least one selected from palladium (Pd), iridium (Ir), rhodium (Rh), and yttrium (Y). Furthermore, when a fluorine-based gas is used to etch the first film 7, it is preferable that the conductive film 2 contains at least one selected from palladium (Pd), zirconium (Zr), and yttrium (Y).

[0058] When the conductive film 2 contains palladium (Pd), the conductive film 2 may have a single-layer structure or a multilayer structure comprising multiple layers. When the conductive film 2 has a single-layer structure, it may be pure Pd, a Pd compound containing Pd and at least one of nitrogen (N), oxygen (O), or boron (B), or a Pd alloy containing Pd and another metal other than Pd. The Pd alloy may contain at least one of N, O, and B. Examples of the other metal include chromium and tantalum. Among the other metals, tantalum is particularly preferred from the viewpoint of chemical resistance, wear resistance, etc. When the conductive film 2 has a single-layer structure made of a Pd compound, the Pd compound preferably contains 50 atomic% or more of Pd, and may contain 99 atomic% or less. The Pd compound may contain 1 atomic% or more of N, and may contain 30 atomic% or less. The Pd compound may contain 1 atomic% or more of O, and may contain 15 atomic% or less. The Pd compound may contain 1 atomic% or more of B, and may contain 30 atomic% or less. Pd compounds do not need to contain all of N, O, and B. Furthermore, if the conductive film 2 has a single-layer structure made of a Pd alloy, the Pd alloy preferably contains 3 atomic% or more of Pd, and can contain 99 atomic% or less. The Pd alloy may contain 1 atomic% or more of N, and can contain 30 atomic% or less. The Pd alloy may contain 1 atomic% or more of O, and can contain 15 atomic% or less. The Pd alloy may contain 1 atomic% or more of B, and can contain 30 atomic% or less. The Pd alloy does not need to contain all of N, O, and B. Note that the conductive film 2 containing Pd in ​​a single-layer structure does not need to contain carbon (C), but may contain C. The C content can be 1 atomic% or more, and is preferably 30 atomic% or less. If the conductive film 2 containing Pd in ​​a single-layer structure contains C, it is preferable that the C content increases further away from the second main surface of the substrate 1.

[0059] When the conductive film 2 has a laminated structure including a Pd-containing layer, the Pd-containing layer can be pure Pd, a Pd compound containing Pd and at least one of N, O, and B, or a Pd alloy containing Pd and other metals other than Pd. When the Pd-containing layer is made of a Pd compound, the Pd compound preferably contains 50 atomic% or more of Pd, and may contain 99 atomic% or less. The Pd compound may contain 1 atomic% or more of N, and may contain 30 atomic% or less. The Pd compound may contain 1 atomic% or more of O, and may contain 15 atomic% or less. The Pd compound may contain 1 atomic% or more of B, and may contain 30 atomic% or less. The Pd compound does not need to contain all of N, O, and B. Furthermore, when the Pd-containing layer is made of a Pd alloy, the Pd alloy preferably contains 3 atomic% or more of Pd, and may contain 99 atomic% or less. The Pd alloy may contain 1 atomic% or more of N, and may contain 30 atomic% or less. Pd alloys may contain 1 atomic percent or more of oxygen and up to 15 atomic percent. Pd alloys may contain 1 atomic percent or more of boron and up to 30 atomic percent. Pd alloys do not need to contain all of N, O, and B. In the case of a laminated structure, conductive film 2 preferably includes other layers containing other metals in addition to the Pd-containing layer. The other layers are preferably made of tantalum-based materials or chromium-based materials. In the case of a laminated structure, the stacking order is not particularly limited. Examples of tantalum-based materials include pure Ta, or Ta and one or more of N, O, B, and C. Examples of chromium-based materials include pure Cr, or Cr and one or more of N, O, B, and C. From the viewpoint of chemical resistance, wear resistance, etc., of conductive film 2, it is particularly preferable that the other layers be made of tantalum-based materials. Also, the Pd-containing layer does not have to contain C, but it may contain C. The C content can be 1 atomic percent or more, and is preferably 30 atomic percent or less. If the Pd-containing layer contains carbon, it is preferable that the carbon content increases as it moves further away from the second main surface of the substrate 1.

[0060] When the conductive film 2 contains iridium (Ir), the conductive film 2 may have a single-layer structure or a multilayer structure comprising multiple layers. In the case of a single-layer structure, it may be pure Ir, an Ir compound containing Ir and at least one of N, O, and B, or an Ir alloy containing Ir and other metals other than Ir. The Ir alloy may contain at least one of N, O, and B. Examples of the other metals include chromium and tantalum. Among the other metals, tantalum is preferred from the viewpoint of chemical resistance, wear resistance, etc. When the conductive film 2 has a single-layer structure made of an Ir compound, the Ir compound preferably contains 50 atomic% or more of Ir and may contain 99 atomic% or less of Ir. The Ir compound may contain 1 atomic% or more of N and 30 atomic% or less of N. The Ir compound may contain 1 atomic% or more of O and 15 atomic% or less of O. The Ir compound may contain 1 atomic% or more of B and 30 atomic% or less of B. The Ir compound does not need to contain all of N, O, and B. When the conductive film 2 has a single-layer structure made of an Ir alloy, the Ir alloy preferably contains 3 atomic percent or more of Ir, and may contain 99 atomic percent or less of Ir. The Ir alloy may contain 1 atomic percent or more of N, and may contain 30 atomic percent or less of N. The Ir alloy may contain 1 atomic percent or more of O, and may contain 15 atomic percent or less of O. The Ir alloy may contain 1 atomic percent or more of B, and may contain 30 atomic percent or less of B. The Ir alloy does not need to contain all of N, O, and B. The conductive film 2 containing Ir in a single-layer structure does not need to contain C, but may contain C. The C content may be 1 atomic percent or more, and preferably 30 atomic percent or less. When the conductive film 2 containing Ir contains C, it is preferable that the C content is higher the further away from the second main surface of the substrate 1 is.

[0061] If the conductive film 2 has a laminated structure including an Ir-containing layer, the Ir-containing layer can be pure Ir, an Ir compound containing Ir and at least one of N, O, and B, or an Ir alloy containing Ir and other metals other than Ir. The Ir compound preferably contains 50 atomic% or more of Ir and may contain 99 atomic% or less of Ir. The Ir compound may contain 1 atomic% or more of N and may contain 30 atomic% or less of N. The Ir compound may contain 1 atomic% or more of O and may contain 15 atomic% or less of O. The Ir compound may contain 1 atomic% or more of B and may contain 30 atomic% or less of B. The Ir compound does not need to contain all of N, O, and B. The Ir alloy preferably contains 3 atomic% or more of Ir and may contain 99 atomic% or less of Ir. The Ir alloy may contain 1 atomic% or more of N and may contain 30 atomic% or less of N. The Ir alloy may contain 1 atomic% or more of O and may contain 15 atomic% or less of O. The Ir alloy contains 1 atomic percent or more of B, and may contain 30 atomic percent or less. The Ir alloy does not need to contain all of N, O, and B. When the Ir-containing layer is the layer in the conductive film 2 that is furthest from the second main surface of the substrate 1, it is preferable that the total content of Ir, N, and O at the outermost surface of the Ir-containing layer exceeds 99.5 atomic percent. In the case of a laminated structure, the conductive film 2 preferably contains other layers containing other metals in addition to the Ir-containing layer. The other layers are preferably made of the above-mentioned tantalum-based material or the above-mentioned chromium-based material. In the case of a laminated structure, the stacking order is not limited. From the viewpoint of the mechanical properties of the conductive film 2, it is particularly preferable that the other layers are made of tantalum-based material. The Ir-containing layer does not have to contain C, but may contain C. The C content can be 1 atomic percent or more, and is preferably 30 atomic percent or less. When the Ir-containing layer contains C, it is preferable that the C content increases the further it is from the second main surface of the substrate 1. When the Ir-containing layer is the layer in the conductive film 2 that is furthest from the second main surface of the substrate 1, it is preferable that the total content of Ir, N, O, and C at the outermost surface of the Ir-containing layer exceeds 99.5 atomic percent.

[0062] When the conductive film 2 contains rhodium (Rh), the conductive film 2 may have a single-layer structure or a multilayer structure comprising multiple layers. In the case of a single-layer structure, it may be pure Rh, an Rh compound containing Rh and at least one of N, O, and B, or an Rh alloy containing Rh and other metals other than Rh. The Rh alloy may contain at least one of N, O, and B. Examples of other metals include chromium and tantalum. Among the other metals, tantalum is preferred from the viewpoint of chemical resistance, wear resistance, etc. The Rh compound preferably contains 50 atomic% or more of Rh and may contain 99 atomic% or less of Rh. The Rh compound may contain 1 atomic% or more of N and may contain 30 atomic% or less of N. The Rh compound may contain 1 atomic% or more of O and may contain 15 atomic% or less of O. The Rh compound may contain 1 atomic% or more of B and may contain 30 atomic% or less of B. The Rh compound does not need to contain all of N, O, and B. When the conductive film 2 has a single-layer structure made of an Rh alloy, the Rh alloy preferably contains 3 atomic percent or more of Rh, and may contain 99 atomic percent or less of Rh. The Rh alloy may contain 1 atomic percent or more of N, and may contain 30 atomic percent or less of N. The Rh alloy may contain 1 atomic percent or more of O, and may contain 15 atomic percent or less of O. The Rh alloy may contain 1 atomic percent or more of B, and may contain 30 atomic percent or less of B. The Rh alloy does not need to contain all of N, O, and B. The conductive film 2 containing Rh in a single-layer structure does not need to contain C, but may contain C. The C content can be 1 atomic percent or more, and is preferably 30 atomic percent or less. When the conductive film 2 containing Rh contains C, it is preferable that the C content is higher the further away from the second main surface of the substrate 1 is.

[0063] When the conductive film 2 has a laminated structure including a Rh-containing layer, the Rh-containing layer can be pure Rh, an Rh compound containing Rh and at least one of N, O, and B, or an Rh alloy containing Rh and other metals other than Rh. When the Rh-containing layer consists of an Rh compound, the Rh compound preferably contains 50 atomic% or more of Rh and can contain 99 atomic% or less of Rh. The Rh compound may contain 1 atomic% or more of N and 30 atomic% or less. The Rh compound may contain 1 atomic% or more of O and 15 atomic% or less. The Rh compound may contain 1 atomic% or more of B and 30 atomic% or less. The Rh compound does not need to contain all of N, O, and B. Furthermore, the Rh alloy preferably contains 3 atomic% or more of Rh and can contain 99 atomic% or less of Rh. The Rh alloy may contain 1 atomic% or more of N and 30 atomic% or less. The Rh alloy contains 1 atomic percent or more of O, and may contain 15 atomic percent or less. The Rh alloy contains 1 atomic percent or more of B, and may contain 30 atomic percent or less. The Rh alloy does not need to contain all of N, O, and B. Preferably, the outermost surface of the Rh-containing layer has a total content of Rh, N, and O exceeding 99.5 atomic percent. In the case of a laminated structure, the conductive film 2 preferably includes other layers containing other metals in addition to the Rh-containing layer. The other layers preferably consist of the above-mentioned tantalum-based material or the above-mentioned chromium-based material. In the case of a laminated structure, the stacking order is not limited. From the viewpoint of the mechanical properties of the conductive film 2, it is particularly preferable that the other layers consist of a tantalum-based material. For example, if another layer is formed on top of the Rh-containing layer, the material of the other layer is preferably Ta alone, a material consisting of Ta and one or more of N and O, or a chromium-based material. The Rh-containing layer does not have to contain C, but may contain C. The C content can be 1 atomic percent or more, and preferably 30 atomic percent or less. If the Rh-containing layer contains carbon, it is preferable that the carbon content increases the further it is from the second main surface of the substrate 1. When the Rh-containing layer is the layer in the conductive film 2 that is furthest from the second main surface of the substrate 1, it is preferable that the total content of Rh, N, O, and C at the outermost surface of the Rh-containing layer exceeds 99.5 atomic percent.

[0064] When the conductive film 2 contains zirconium (Zr), the conductive film 2 may have a single-layer structure or a multilayer structure comprising multiple layers. In the case of a single-layer structure, it may be pure Zr, a Zr compound containing Zr and at least one of N, O, or B, or a Zr alloy containing Zr and other metals other than Zr. When the conductive film 2 contains Zr, it does not have to contain B. The Zr alloy may contain at least one of N, O, or B. Examples of other metals include chromium and tantalum. Among the other metals, tantalum is preferred from the viewpoint of chemical resistance, wear resistance, etc. When the conductive film 2 has a single-layer structure made of a Zr compound, the Zr compound preferably contains 50 atomic% or more of Zr and may contain 99 atomic% or less of Zr. The Zr compound may contain 1 atomic% or more of N and may contain 30 atomic% or less of N. The Zr compound may contain 1 atomic% or more of O and may contain 15 atomic% or less of O. The Zr compound may contain 1 atomic percent or more of B and up to 30 atomic percent. The Zr compound does not need to contain all of N, O, and B. Furthermore, if the conductive film 2 has a single-layer structure made of a Zr alloy, the Zr alloy preferably contains 3 atomic percent or more of Zr and up to 99 atomic percent of Zr. The Zr alloy may contain 1 atomic percent or more of N and up to 30 atomic percent. The Zr alloy may contain 1 atomic percent or more of O and up to 15 atomic percent. The Zr alloy may contain 1 atomic percent or more of B and up to 30 atomic percent. The Zr alloy does not need to contain all of N, O, and B. The single-layer conductive film 2 containing Zr does not need to contain C, but may contain C. The C content may be 1 atomic percent or more and preferably 30 atomic percent or less. If the conductive film 2 containing Zr contains C, it is preferable that the C content is higher the further it is from the second main surface of the substrate 1.

[0065] When the conductive film 2 has a laminated structure including a Zr-containing layer, the Zr-containing layer can be pure Zr, a Zr compound containing Zr and at least one of N, O, and B, or a Zr alloy containing Zr and other metals other than Zr. When the Zr-containing layer is made of a Zr compound, the Zr compound preferably contains 50 atomic% or more of Zr and may contain 99 atomic% or less of Zr. The Zr compound may contain 1 atomic% or more of N and 30 atomic% or less of N. The Zr compound may contain 1 atomic% or more of O and 15 atomic% or less of O. The Zr compound may contain 1 atomic% or more of B and 30 atomic% or less of B. The Zr compound does not need to contain all of N, O, and B. Furthermore, when the Zr-containing layer is made of a Zr alloy, the Zr alloy preferably contains 3 atomic% or more of Zr and may contain 99 atomic% or less of Zr. The Zr alloy may contain 1 atomic% or more of N and 30 atomic% or less of N. Zr alloys may contain 1 atomic percent or more of oxygen and up to 15 atomic percent. Zr alloys may contain 1 atomic percent or more of boron and up to 30 atomic percent. Zr alloys do not need to contain all of N, O, and B. Other metals to be included in a Zr alloy are not particularly limited, but examples include chromium and tantalum. From the viewpoint of chemical resistance, wear resistance, etc., tantalum is particularly preferred as the other metal. The Zr-containing layer does not need to contain B. When the conductive film 2 has a laminated structure, it is preferable to include other layers containing other metals in addition to the Zr-containing layer. The other layers are preferably made of the above-mentioned tantalum-based material or the above-mentioned chromium-based material. In the case of a laminated structure, the order of stacking is not limited. From the viewpoint of the mechanical properties of the conductive film 2, it is particularly preferable that the other layers be made of a tantalum-based material. When the Zr-containing layer is formed in contact with the second main surface of the substrate 1, the material of the other layer provided on top of the Zr-containing layer can be a chromium-based material, Ta, or a material containing Ta and one or more of N, O, and C. If other layers are formed beneath the Zr-containing layer, the material of the other layers may be Ta or a material containing Ta and one or more of N and C. The Zr-containing layer may or may not contain C. The C content can be 1 atomic percent or more, and preferably 30 atomic percent or less. If the Zr-containing layer contains C, it is preferable that the C content increases the further it is from the second main surface of the substrate 1.When the Zr-containing layer is the layer in the conductive film 2 that is furthest from the second main surface of the substrate 1, it is preferable that the total content of Zr, N, O, B, and C at the outermost surface of the Zr-containing layer exceeds 99.5 atomic percent.

[0066] When the conductive film 2 contains yttrium (Y), the conductive film 2 may have a single-layer structure or a multilayer structure comprising multiple layers. In the case of a single-layer structure, it may be Y alone, a Y compound containing Y and at least one of N, O, and B, or a Y alloy containing Y and other metals other than Y. The Y alloy may contain at least one of N, O, and B. Examples of other metals include chromium and tantalum. Among the other metals, tantalum is preferred from the viewpoint of chemical resistance, wear resistance, etc. When the conductive film 2 has a single-layer structure made of a Y compound, the Y compound preferably contains 50 atomic% or more of Y and may contain 99 atomic% or less of Y. The Y compound may contain 1 atomic% or more of N and may contain 30 atomic% or less of N. The Y compound may contain 1 atomic% or more of O and may contain 15 atomic% or less of O. The Y compound may contain 1 atomic% or more of B and may contain 30 atomic% or less of B. The Y compound does not need to contain all of N, O, and B. When the conductive film 2 has a single-layer structure made of a Y alloy, the Y alloy preferably contains 3 atomic percent or more of Y, and may contain 99 atomic percent or less of Y. The Y alloy may contain 1 atomic percent or more of N, and may contain 30 atomic percent or less of N. The Y alloy may contain 1 atomic percent or more of O, and may contain 15 atomic percent or less of O. The Y alloy may contain 1 atomic percent or more of B, and may contain 30 atomic percent or less of B. The Y alloy does not need to contain all of N, O, and B. The conductive film 2 containing Y in a single-layer structure does not need to contain C, but may contain C. The C content can be 1 atomic percent or more, and is preferably 30 atomic percent or less. When the conductive film 2 containing Y contains C, it is preferable that the C content is higher the further it is from the second main surface of the substrate 1.

[0067] Furthermore, if the conductive film 2 has a laminated structure including a Y-containing layer, the Y-containing layer can be pure Y, a Y compound containing Y and at least one of N, O, and B, or a Y alloy containing Y and other metals other than Y. When the Y-containing layer is made of a Y compound, the Y compound preferably contains 50 atomic% or more of Y and 99 atomic% or less of Y. The Y compound may contain 1 atomic% or more of N and 30 atomic% or less. The Y compound may contain 1 atomic% or more of O and 15 atomic% or less. The Y compound may contain 1 atomic% or more of B and 30 atomic% or less. The Y compound does not need to contain all of N, O, and B. Furthermore, if the Y-containing layer is made of a Y alloy, the Y alloy preferably contains 3 atomic% or more of Y and 99 atomic% or less of Y. The Y alloy may contain 1 atomic% or more of N and 30 atomic% or less. The Y alloy may contain 1 atomic% or more of O and 15 atomic% or less. The Y alloy contains 1 atomic percent or more of B, and may contain 30 atomic percent or less. The Y alloy does not need to contain all of N, O, and B. Preferably, the outermost surface of the Y-containing layer has a total content of Y, N, O, and B exceeding 99.5 atomic percent. If the conductive film 2 has a laminated structure, it is preferable to include other layers containing other metals in addition to the Y-containing layer. The other layers are preferably made of the above-mentioned tantalum-based material or the above-mentioned chromium-based material. In the case of a laminated structure, the order of stacking is not limited. From the viewpoint of chemical resistance, wear resistance, etc., of the conductive film 2, it is particularly preferable that the other layers be made of a tantalum-based material. If the Y-containing layer is provided on top of other layers, examples of materials for the other layers include TaN, TaB, and TaBN. The Y-containing layer does not have to contain C, but may contain C. The C content can be 1 atomic percent or more, and is preferably 30 atomic percent or less. If the Y-containing layer contains C, it is preferable that the C content is higher the further it is from the second main surface of the substrate 1. Furthermore, if the Y-containing layer is the layer in the conductive film 2 that is furthest from the second main surface of the substrate 1, it is preferable that the total content of Y, N, O, B, and C at the outermost surface of the Y-containing layer exceeds 99.5 atomic percent.

[0068] The thickness of the conductive film 2 is not particularly limited, but whether the conductive film 2 is a single layer or a multilayer film, it is preferably 10 nm or more, and more preferably 20 nm or more. Furthermore, the thickness is preferably 500 nm or less, more preferably 200 nm or less, and even more preferably 100 nm or less. Also, if the conductive film 2 is a multilayer film, the thickness ratio of each layer is not particularly limited. The method for depositing the conductive film 2 is not particularly limited, but magnetron sputtering or ion beam sputtering is usually preferred.

[0069] Furthermore, it is preferable that the conductive film 2 is amorphous. This allows the surface of the conductive film 2 to be smooth and flat.

[0070] Furthermore, it is preferable that the conductive film 2 has compressive stress. Specifically, the compressive stress of the conductive film 2 is preferably 0.3 GPa or higher. It is more preferable that the compressive stress of the conductive film 2 is 2 GPa or lower. By having compressive stress in the conductive film 2, for example, when a multilayer reflective film is formed on the first main surface of the substrate 1, it is possible to reduce the warping of the substrate 1 caused by the multilayer reflective film.

[0071] Furthermore, it is preferable that the transmittance of the conductive film 2 to light with a wavelength of 1030 nm is 1.0% or more, more preferably 2.0% or more, and particularly preferably 2.5% or more. This allows light with a wavelength of 1030 nm to be irradiated onto the substrate 1 through the conductive film 2, thereby improving deformation of the substrate 1.

[0072] To solve the above-mentioned problems, the inventors focused on the vapor pressure of the halogen compound of metal M1 contained in the conductive film and, after diligent research, completed the present invention. According to the present invention, by deriving the vapor pressure curve of the halogen compound of metal M1 contained in the conductive film, if the vapor pressure Pm of the halogen compound is lower than the pressure Pch at temperature Tch in the etching chamber where the actual etching of the first film 7 is performed, it can be determined that the conductive film has high resistance to etching of the first film.

[0073] As described above, in the present invention, for example, in the mask blank 10 of this embodiment, when the pressure Pch and temperature Tch are used to etch the first film 7 with a halogen, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower at temperature Tch than at pressure Pch. This makes it possible to suppress damage to the conductive film 2 due to etching of the first film 7, even when, for example, a difficult-to-etch material is used for the first film 7.

[0074] In the etching conditions used to etch the first film 7, the pressure Pch and temperature Tch in the chamber where the first film 7 is etched are both set to etch the first film 7 with a halogen. The halogen is preferably fluorine or chlorine. Although it varies depending on the film composition of the first film 7, the etching of the first film 7 can be performed by dry etching using, for example, a fluorine-based gas or a chlorine-based gas. As for fluorine-based gases, F ２ Gas, CF ４ Perfluorocarbon gases such as CFH ３ Hydrofluorocarbon gases such as SF ６ Gas, NF ３ Gas, SiF ４ Examples include gases and HF gases. These fluorine-based gases may also further contain noble gases and / or oxygen. Examples of chlorine-based gases include Cl ２ SiCl ２ , CHCl ３ ,CH ２ Cl ２ , CCl ４ , BCl ３ These are some examples. This chlorine-based gas may further contain noble gases and / or oxygen.

[0075] The following describes the procedure for deriving the vapor pressure curve of the halogen compound of metal M1 contained in the conductive film in the present invention. In the present invention, the vapor pressure curve is drawn from the following Clausius-Clapeyron equation (Equation (1) below). In Equation (1) below, the pressure is P and the temperature is T (K).

[0076]

[0077] In the Clausius-Clapeyron equation above, temperature T １ (K) and pressure P １ As known data, data on the boiling point at atmospheric pressure can be used for the halogen compound (e.g., fluoride or chloride) of metal M1 contained in the conductive film. In this invention, the above metal M1 is at least one selected from, for example, palladium, iridium, rhodium, zirconium, and yttrium. Specifically, data from publicly available databases, such as the CRC Chemistry and Physics Handbook, 100th Edition (Publisher: CRC Pr., published June 27, 2019), can be used. In the Clausius-Clapeyron equation above, R is the gas constant.

[0078] Furthermore, in the Clausius-Clapeyron equation above, ΔHv is the molar latent heat of vaporization (J / mol). If the molar latent heat of vaporization is not listed in the database, etc., it is necessary to estimate it. The molar latent heat of vaporization ΔHv (cal / mol) can be estimated from Hildebrand's general rule (Equation (2)) below. ΔHv = 38.3Tb - 5426 ...Equation (2) In Equation (2), the unit of the molar latent heat of vaporization ΔHv is cal / mol. Therefore, the molar latent heat of vaporization ΔHv (cal / mol) obtained from Equation (2) should be converted to the value in J / mol as appropriate.

[0079] In equation (2) above, Tb(K) is the standard boiling point. If only the normal boiling point is listed in a database, etc., it is necessary to convert it to the standard boiling point. The normal boiling point refers to the boiling point at 1 atmosphere. The standard boiling point refers to the boiling point at a pressure of 1 bar. For example, the standard boiling point can be converted using a known method such as a pressure-temperature nomograph. Alternatively, the standard boiling point can be converted using a calculation function available on a publicly available website. As a pressure-temperature nomograph, for example, you can use the nomograph published on a publicly available website (URL: https: / / www.tcichemicals.com / assets / cms-pdfs / pressure-temperature-nomograph.pdf) or in the book "The Science of Petroleum, Vol.II. p.1284 (1938). Dunstan, AE et al., Kogyo Tosho Shuppansha". If the obtained standard boiling point is in Celsius (°C), it should be converted to absolute temperature (K) as appropriate. Furthermore, since the molar latent heat of vaporization is temperature-dependent, the molar latent heat of vaporization at temperatures other than the standard boiling point is required. Additionally, the molar latent heat of vaporization can be estimated using the following Watson equation (equation (3) below).

[0080]

[0081] In the Watson equation above, ΔH Tref is the molar latent heat of vaporization at the reference temperature Tref (K), and the data for the molar latent heat of vaporization at the standard boiling point obtained from Hildebrand's general rule above is used. Tc is the critical temperature (K), but if it is not listed in the database, estimation is necessary. For inorganic substances containing halogens, the critical temperature Tc (K) is estimated using the following equation (4): Tc = 1.38(Tb - 273.15) + 450 - 11F ...Equation (4)

[0082] In equation (4) above, Tb(K) is the standard boiling point data obtained above. Also, F is the number of F atoms contained in one molecule. In this invention, a molecule is a halogen compound of metal M1 derived from a conductive film. Next, using the data obtained above, the equation for the temperature dependence of the molar latent heat of vaporization is derived from the Watson equation above.

[0083] The ΔHv (J / mol) and atmospheric pressure P were determined as described above. １ , normal boiling point T １ Using (K), the standard boiling point Tb(K), the number of F atoms in the molecule F, and the gas constant R, the vapor pressure curve of the halogen compound of metal M1 derived from the conductive film can be drawn from the Clausius-Clapeyron equation shown in equation (1) above.

[0084] The procedure for deriving the vapor pressure curve described above can be summarized as follows: 1. Find the boiling point at atmospheric pressure in the database. 2. Convert the boiling point obtained in step 1 to the standard boiling point. 3. Estimate the critical temperature using the data obtained in step 2. 4. Estimate the molar latent heat of vaporization at the standard boiling point using Hildebrand's general rule. 5. Using the data obtained in steps 3 and 4, derive the equation for the temperature dependence of the molar latent heat of vaporization from the Watson equation. 6. Using the equation obtained in step 5, the vapor pressure curve can be drawn from the Clausius-Clapeyron equation.

[0085] Figure 8 shows an example of the vapor pressure curve of a halogen compound of metal M1 derived from the conductive film prepared by the above procedure. In the example shown in Figure 8, the vapor pressure Pm of the halogen compound is lower than the pressure Pch at temperature Tch in the etching chamber where the actual first film 7 (e.g., absorber film) is etched. Therefore, it can be determined that the conductive film has high resistance to etching of the first film.

[0086] Furthermore, if the conductive film 2 contains two or more of the metals M1, a vapor pressure curve for the halide of each metal is created, and the vapor pressure Pm of the halogen compound at temperature Tch in the etching chamber is determined. Of the obtained vapor pressures Pm of the metal halogen compounds, at least one must be lower than the pressure Pch in the etching chamber. For example, if the conductive film contains metal A and metal B, the vapor pressure of the halogen compound AH of metal A and the vapor pressure of the halogen compound BH of metal B are calculated separately at temperature Tch in the etching chamber. At least one of the vapor pressures of halogen compound AH and halogen compound BH must be lower than the pressure Pch. Alternatively, both the vapor pressure of halogen compound AH and halogen compound BH may be lower than the pressure Pch.

[0087] In the present invention, it is preferable that the etching rate of the first film 7 is greater than 0. For example, the effects of the present invention can be obtained more favorably under etching conditions in which the etching rate of the first film 7 is 0.5 nm / second or less, and particularly 0.2 nm / second or less. For this reason, under etching conditions as described above, it is preferable that the vapor pressure Pm of the halogen compound is lower than the pressure Pch at the temperature Tch in the etching chamber. The present invention is particularly effective 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, and particularly 20 nm or more. Furthermore, when the film thickness of the first film 7 is 10 nm or less, the effects of the present invention are better when the etching rate of the first film 7 is 0.02 nm / second or less.

[0088] In the present invention, for example, in the mask blank 10 in this embodiment, when the first film 7 is etched under the etching conditions described above, the amount of film 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. Preferably, the amount of film reduction at the outer periphery of the conductive film 2 after etching of the first film 7 is 15% or less, and more preferably 10% or less. The outer periphery of the conductive film 2 referred to 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 of the substrate 1. If the film thickness at the outer periphery of the conductive film 2 is not constant in the plane, the amount of film reduction can be calculated by subtracting the average value of the film thickness at the outer periphery of the conductive film 2 after etching from the average value of the film thickness at the outer periphery of the conductive film 2 before etching of the first film 7. If the film thickness of the outer periphery of the conductive film 2 is not constant in the plane, for example, the film thickness of the outer periphery of the conductive film 2 gradually decreases as it approaches the edge of the conductive film 2 in a cross-sectional view. The amount of film reduction can be measured at at least one location on the outer periphery of the conductive film 2, but it may also be the average value of the film reduction amounts at the center points of each of the four edges of the conductive film 2.

[0089] As described above, according to the present invention, for example, in the mask blank 10 of this embodiment, when the pressure Pch and temperature Tch are used to etch the first film 7 with a halogen, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower at temperature Tch than at pressure Pch. Therefore, even when a difficult-to-etch material is used for the first film 7, damage to the conductive film 2 due to etching of the first film 7 can be suppressed. For example, even when a difficult-to-etch material is used for an absorber film, damage to the conductive film due to etching of the absorber film, etc., during the manufacturing process of a reflective mask can be reduced.

[0090] [Multilayer Reflective Film Substrate] Next, a multilayer reflective film substrate, which is a type of mask blank of the present invention described above, will be explained. Figure 2 is a cross-sectional view showing one embodiment of a multilayer reflective film substrate. As shown in Figure 2, in the multilayer reflective film substrate 20 according to one embodiment, a multilayer reflective film 3 that reflects EUV light, which is exposure light, is formed on the first main surface (upper surface of the substrate 1 in Figure 2) of the substrate 1 in the mask blank 10. That is, in this case, the first film 7 in the mask blank 10 can be the multilayer reflective film 3.

[0091] The multilayer reflective substrate 20 of this embodiment is manufactured by forming a multilayer reflective film 3 on the first main surface of the substrate 1 that reflects, for example, EUV light as exposure light. The mask blanks (reflective mask blanks 30, 40, 50) and the reflective mask 60 described later are all types of the multilayer reflective substrate 20, as they include the multilayer reflective film 3 on the first main surface of the substrate 1.

[0092] The multilayer reflective film 3 described above is a multilayer film in which low refractive index layers and high refractive index layers are alternately stacked. Generally, the multilayer reflective film 3 is 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 for about 30 to 60 periods. For example, as a multilayer reflective film for EUV light with a wavelength of 13 to 14 nm, a Mo / Si periodic multilayer film in which Mo films and Si films are alternately stacked for about 40 periods is preferably used. Other multilayer reflective films used in the EUV light region 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 periodic multilayer films, Si / Ru / Mo / Ru periodic multilayer films, etc. The material of the multilayer reflective film should be appropriately selected according to the exposure wavelength.

[0093] Normally, a protective film is provided on the multilayer reflective film 3 for the purpose of protecting the multilayer reflective film during patterning of the absorber film or modification of the absorber film pattern. The protective film is sometimes called a capping layer. Such a protective film can be formed from a material mainly composed of ruthenium. Materials mainly composed of ruthenium include elemental Ru metal, Ru alloys containing 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 may also be formed from a material mainly composed of rhodium. Furthermore, the protective film may have, for example, a layer mainly composed of ruthenium and a layer mainly composed of rhodium. Furthermore, "containing substance A as the main component" means that substance A is present in the largest quantity. Also, the thickness of the protective film is preferably, for example, 1 nm or more. Furthermore, the thickness of the protective film is preferably 5 nm or less.

[0094] In a multilayer reflective film substrate comprising a multilayer reflective film 3 including alternately stacked high refractive index layers and low refractive index layers on the first main surface of the substrate 1 in the mask blank 10, or the multilayer reflective film 3 and the protective film formed on the multilayer reflective film 3, the first film 7 in the mask blank 10 can be the multilayer reflective film 3 or the protective film.

[0095] The method for forming the multilayer reflective film 3 and the protective film is not particularly limited, but ion beam sputtering and magnetron sputtering are generally preferred.

[0096] In the multilayer reflective film substrate 20 of this embodiment, when pressure Pch and temperature Tch are used to etch the multilayer reflective film 3 or the protective film with a halogen, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower than the pressure Pch at temperature Tch. This makes it possible to suppress damage to the conductive film 2 due to etching of the multilayer reflective film 3 or the protective film, even when, for example, a difficult-to-etch material is used for the multilayer reflective film 3 or the protective film.

[0097] [Reflective Mask Blank] Next, a reflective mask blank, which is a type of mask blank 10 or multilayer reflective film substrate 20 of the present invention described above, will be explained. Figure 3 is a cross-sectional view showing one embodiment of a reflective mask blank. As shown in Figure 3, in a reflective mask blank 30 according to one embodiment, a multilayer reflective film 3 that reflects EUV light, which is exposure light, is formed on the first main surface of the substrate 1 in the mask blank 10, and an absorber film 5 is formed on the multilayer reflective film 3. In Figure 3, the first main surface is the upper surface of the substrate 1. The conductive film 2 is formed on the second main surface of the substrate 1. That is, in the reflective mask blank 30 of this embodiment, the first film 7 in the mask blank 10 can be an absorber film 5 formed on the multilayer reflective film 3.

[0098] The reflective mask blank 30 described above is manufactured by depositing a multilayer reflective film 3 that reflects EUV light and an absorber film 5 that absorbs EUV light in that order on the first main surface of the substrate 1.

[0099] The absorber film 5 described above can absorb exposure light, such as EUV light. In the reflective mask 60 (see Figure 6) obtained by patterning the absorber film 5 of the reflective mask blank, the absorber film 5 is configured such that the reflected light from the absorber film pattern 5a (see Figure 6) has a desired reflectance difference with respect to the reflected light from the multilayer reflective film 3 or the protective film on the multilayer reflective film 3. For example, the reflectance difference of the absorber film 5 with respect to EUV light is selected to be between 0.1% and 40%. In addition to the above reflectance difference, the absorber film 5 may also be configured such that the reflected light from the absorber film pattern 5a irradiated with EUV light has a desired phase difference with respect to the reflected light from the multilayer reflective film 3 or the protective film irradiated with EUV light. Furthermore, if the reflected light from the absorber film pattern 5a, irradiated with EUV light, has a desired phase difference with respect to the reflected light from the multilayer reflective film 3 or the protective film, the absorber film 5 in the reflective mask blank may be referred to as a phase-shift film. When improving contrast by providing a desired phase difference between the reflected light from the multilayer reflective film 3 or the protective film and the reflected light from the absorber film pattern 5a, it is preferable to set the phase difference with respect to EUV light in the range of 150 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.

[0100] The absorber film 5 described above may be a single-layer structure or a multilayer structure. If the absorber film 5 has a multilayer structure, it may consist of a multilayer film of the same material or a multilayer film of different materials. The multilayer film may have a material and / or composition that changes stepwise and / or continuously in the film thickness direction. If the absorber film 5 is a multilayer film, the absorber film 5 may include, for example, a layer (buffer layer) that has etching selectivity with respect to the protective film at the position closest to the substrate in the film thickness direction.

[0101] The material of the absorber film 5 is not particularly limited, as long as it is a material that absorbs EUV light, can be processed by etching, etc., and has a high etching selectivity ratio compared to the multilayer reflective film 3 or protective film. Preferably, the material of the absorber film 5 is etchable by dry etching with a chlorine (Cl)-based gas and / or a fluorine (F)-based gas. As the material for the absorber membrane 5 having the above-described functions, it is preferable to use 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. The material of the absorbent membrane 5 may include, in addition to the above-mentioned metal, alloy, or compound, oxygen (O), nitrogen (N), carbon (C), hydrogen (H), and / or boron (B).

[0102] The thickness of the absorber film 5 is preferably in the range of, for example, 30 nm to 100 nm. The method for forming the absorber film 5 is not particularly limited, but magnetron sputtering or ion beam sputtering is usually preferred.

[0103] The configuration of the multilayer reflective film 3 in the reflective mask blank 30 is as described in the description of the substrate 20 with the multilayer reflective film. As for the material of the multilayer reflective film 3, in this embodiment as well, the same material as the material of the multilayer reflective film described in the substrate 20 with the multilayer reflective film can be used.

[0104] Details regarding the configuration of the conductive film 2 in the reflective mask blank 30 are as described in the description of the mask blank 10 above.

[0105] In the reflective mask blank 30 of this embodiment, when etching the absorber film 5 (first film), the pressure Pch and temperature Tch are used to etch the absorber film 5 with a halogen, and the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower than the pressure Pch at temperature Tch.

[0106] The etching conditions used to etch the absorber film 5 vary depending on the film composition of the absorber film 5, but for example, dry etching using a fluorine-based gas or a chlorine-based gas can be used.

[0107] The etching rate of the absorber film 5 under these etching conditions is preferably 0.5 nm / second or less, and more preferably 0.2 nm / second or less. The etching rate of the absorber film 5 under these etching conditions is greater than 0.

[0108] When the absorber film 5 is etched under the etching conditions described above in 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. Preferably, the amount of film thickness reduction at the outer periphery of the conductive film 2 after etching of the absorber film 5 is 15% or less of the film thickness at the outer periphery of the conductive film 2 before etching of the absorber film 5, and more preferably 10% or less.

[0109] As described above, according to the present invention, for example, when etching the absorber film 5 in the reflective mask blank 30 of this embodiment, when the pressure Pch and temperature Tch are used to etch the absorber film 5 with a halogen, the vapor pressure Pm of the halogen and the halogen compound consisting of the metal M1 is lower at temperature Tch than the pressure Pch. 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 due to 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.

[0110] Figure 4 is a cross-sectional view showing another embodiment of the reflective mask blank described above. As shown in Figure 4, the 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. Details regarding the configuration of the multilayer reflective film 3, absorber film 5 and conductive film 2 in this embodiment are the same as in the previously described embodiment.

[0111] Furthermore, Figure 5 is a cross-sectional view showing yet another embodiment of the reflective mask blank described above. As shown in Figure 5, in the reflective mask blank 50 of this embodiment, an etching mask film 6 is formed on the absorber film 5. In the reflective mask blank 50 of this embodiment, the first film 7 in the mask blank 10 can be the etching mask film 6 or the absorber film 5.

[0112] The etching mask film 6 described above functions as a mask when patterning the absorber film 5. The etching mask film 6 is composed of a material with different etching selectivity from the material of the uppermost layer of the absorber film 5. For example, the material of the etching mask film 6 can be one of the materials listed above for the absorber film 5. The material of the etching mask film 6 can be selected appropriately depending on the material of the absorber film 5. For example, if the absorber film 5 is made of pure Ta or a material containing Ta, the etching mask film 6 can be made of materials such as chromium, chromium compounds, silicon, or silicon compounds. 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, metallic silicon (metallic silicide) containing silicon or a silicon compound and a metal, or metallic silicon compounds (metallic silicide compounds). Examples of metallic silicon compounds include materials containing a metal, Si, and at least one element selected from N, O, C, and H. Furthermore, in the case where the absorber film 5 is a multilayer film formed on a multilayer reflective film 3 in the order of a material containing Ta and a material containing Cr, the material of the etching mask film 6 can be selected from silicon, silicon compounds, metal silicides, or metal silicide compounds, which have different etching selectivity from the material containing Cr.

[0113] Furthermore, in the reflective mask blank 50 according to this embodiment (the same applies to the reflective mask blanks 30 and 40 described above), the absorber film 5 can be composed of a laminated film of an uppermost layer and other layers made of materials with different etching selectivity, and the uppermost layer can be configured to function as an etching mask film for the other layers.

[0114] Details regarding the configuration of the multilayer reflective film 3, absorber film 5, and conductive film 2 in this embodiment are the same as in the previously described embodiment.

[0115] When etching the etching mask film 6 or the absorber film 5 in the reflective mask blank 50 of this embodiment, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower at temperature Tch than the pressure Pch when the pressure Pch and temperature Tch are used to etch the etching mask film 6 or the absorber film 5 with a halogen. Therefore, even when a material that is difficult to etch is used for the etching mask film 6 or the absorber film 5, for example, damage to the conductive film 2 due to etching of 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.

[0116] Furthermore, the reflective mask blanks 30, 40, and 50 according to the above-described embodiment also include embodiments in which a resist film is formed on the absorber film 5 or etching mask film 6. Such a resist film is used when patterning the absorber film 5 in the reflective mask blank by lithography.

[0117] [Mask] Next, a mask made using the mask blank 10 will be described. The mask of the present invention comprises 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 a conductive film formed on the second main surface. The conductive film contains a metal M1. The first film has a transfer pattern. When pressure Pch and temperature Tch are used to etch the first film with a halogen, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower than the pressure Pch at temperature Tch. Since the mask of the present invention is made using the mask blank 10, when the first film is further etched under the above etching conditions, the conductive film of the mask of the present invention exhibits the same properties as the conductive film of the mask blank 10.

[0118] Here, as one embodiment of the above-described mask, a reflective mask made using the above-described reflective mask blank 30, etc., will be explained. Figure 6 is a cross-sectional view showing one embodiment of the above-described reflective mask. As shown in Figure 6, the reflective mask 60 of this embodiment has an absorber film pattern 5a obtained by patterning the absorber film 5 of the aforementioned reflective mask blank 40 by etching, for example. In the reflective mask 60 of this embodiment, the first film 7 on the mask blank 10 is an absorber film 5 formed on the protective film 4.

[0119] For example, the most preferred method for patterning the absorber film 5, which will become the transfer pattern on the reflective mask blank 40, is EUV (or electron beam) lithography. That is, a resist film is formed by baking an electron beam resist coated on the reflective mask blank 40. A resist pattern corresponding to the transfer pattern (absorber film pattern 5a) is formed on the resist film by drawing on it using an electron beam lithography apparatus and then developing it. After that, the absorber film 5 is patterned using this resist pattern as a mask to form the absorber film pattern 5a. The resist pattern is then removed. The reflective mask 60 shown in Figure 6 is thus produced.

[0120] Furthermore, the protective film 4 exposed by forming the absorber film pattern 5a may ultimately be removed, but it does not need to be removed if its remaining presence does not affect the function of the reflective mask. Also, when manufacturing a reflective mask using a reflective mask blank 50 having the above-described etching mask film 6, the etching mask film 6 may ultimately be removed, but it does not need to be removed if its remaining presence does not affect the function of the reflective mask.

[0121] As mentioned above, even when a difficult-to-etch material is used for the etching mask film 6 or the absorber film 5, damage to the conductive film 2 due to 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.

[0122] The present invention also provides other embodiments of the mask blank described above. Figure 7 is a cross-sectional view showing another embodiment of the mask blank of the present invention. As shown in Figure 7, the mask blank 70 of this embodiment comprises a substrate 1 having a first main surface and a second main surface facing opposite to the first main surface, a first film 7 formed on the first main surface, and a conductive film 2 formed on the second main surface. In Figure 7, the first main surface is the upper surface of the substrate 1. In Figure 7, the second main surface is the lower surface of the substrate 1. The thickness of the conductive film 2 near the outer periphery is formed to be greater (thicker) than the thickness of the conductive film 2 at its center. When the first film 7 is etched under etching conditions in which pressure Pch and temperature Tch are used to etch the first film 7, the thickness of the conductive film 2 near the outer periphery is formed to be greater (thicker) in advance, taking into account the amount of film reduction at 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 its outer periphery, by etching the first film 7 under the etching conditions described above, the desired film thickness of the conductive film 2 can be maintained.

[0123] The aforementioned multilayer reflective substrate is a type of mask blank 70 because it includes a conductive film 2 on the second main surface of the substrate 1. Furthermore, both the aforementioned mask blanks (reflective mask blanks 30, 40, and 50) and the reflective mask 60 described above are also a type of mask blank 70 because they include a conductive film 2 on the second main surface of the substrate 1.

[0124] The outer periphery of the conductive film 2 is as described above with respect to the mask blank 10. The outer periphery of the conductive film 2 can also be, for example, an area within 2.0 mm from the edge of the second main surface 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 film thickness of the outer periphery of the conductive film 2 does not need to be constant; for example, the average value of the film thickness of the outer periphery should be greater than the film thickness at the center of the conductive film 2. Preferably, the film thickness of the outer periphery of the conductive film 2 is greater than the film thickness at the center of the conductive film 2 across the entire outer periphery of the conductive film 2. This makes it possible to maintain the film thickness of the outer periphery of the conductive film 2 within an appropriate range after etching of the first film.

[0125] The thickness of the conductive film 2 on its outer periphery may be, for example, greater closer to the edge of the second main surface of the substrate 1. In this case, the thickness of the conductive film 2 on its outer periphery may increase continuously or in steps closer to the edge of the second main surface of the substrate 1. That is, in a cross-sectional view, the conductive film 2 may have a gradient region on its outer periphery where the thickness changes continuously or in steps. Alternatively, the thickness of the conductive film 2 on its outer periphery may be constant in the region within 2.0 mm of the second main surface of the substrate 1 or the edge of the conductive film 2.

[0126] The thickness of the outer periphery of the conductive film 2 is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more, than the thickness of the center of the conductive film 2. If the thickness of the outer periphery of the conductive film 2 is not constant in the plane, the largest thickness on the outer periphery of the conductive film 2 is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more, than the thickness of the center of the conductive film 2. These configurations allow for more effective maintenance of the desired thickness of the conductive film 2. Furthermore, the difference between the thickness of the outer periphery of the conductive film 2 and the thickness of the center of the conductive film 2 is preferably 40% or less, and more preferably 30% or less, than the thickness of the center of the conductive film 2. If the thickness of the outer periphery of the conductive film 2 is not constant in the plane, the difference between the largest thickness on the outer periphery of the conductive film 2 and the thickness of the center of the conductive film 2 is preferably 40% or less, and more preferably 30% or less, than the thickness of the center of the conductive film 2. These configurations allow for maintaining the thickness of the outer periphery of the conductive film 2 within an appropriate range after etching of the first film. Furthermore, it can suppress problems with substrate adsorption by electrostatic chucks, deterioration of reflective mask quality, and reduction in pattern transfer accuracy.

[0127] To increase the thickness of the outer periphery of the conductive film 2, the following steps can be taken. First, as a first film deposition, the conductive film 2 is deposited on the second main surface of the substrate 1, similar to the conductive film 2 described in the mask blank 10 above. Then, as a second film deposition, additional film deposition can be performed 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 deposition is also part of the conductive film 2. The sputtering gas used in the second film deposition may be the same as that used in the first film deposition, or it may be changed from the one used in the first film deposition as needed. In the second film deposition, the sputtering target used in the first film deposition 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 deposition may be the same as the material of the conductive film 2 formed in the first film deposition, or it may be different from the material of the conductive film 2 formed in the first film deposition.

[0128] Details regarding the composition of the conductive film 2 other than its thickness can be the same as those described in the mask blank 10 above. The material of the conductive film 2 is not particularly limited, as long as the thickness of the outer periphery of the conductive film 2 is greater than the thickness of the center of the conductive film 2, but it can be, for example, the same as the material of the conductive film 2 described in the mask blank 10 above.

[0129] [Method for Manufacturing Semiconductor Devices] Furthermore, a method for manufacturing semiconductor devices will also be described. By using the reflective mask 60 of the above-described embodiment and exposing the transfer pattern (absorber film pattern 5a) to a transfer target, for example, a resist film on a semiconductor substrate, a high-quality semiconductor device with few defects can be manufactured.

[0130] The reflective mask 60 manufactured from the aforementioned mask blanks (for example, reflective mask blanks 30, 40, and 50) suffers minimal damage to the conductive film. Therefore, it does not affect the substrate adsorption force by the electrostatic chuck, the quality of the reflective mask, or the pattern transfer accuracy. Consequently, by performing pattern transfer using this reflective mask 60 with minimal conductive film damage, good substrate adsorption force by the electrostatic chuck can be obtained. This allows for high-precision pattern transfer without causing misalignment during exposure.

[0131] As described in detail above, according to the present invention, even when a difficult-to-etch material is used for the absorber film, etc., a mask blank can be obtained in which the conductive film is less damaged by etching of the absorber film, etc. during mask manufacturing. Furthermore, the mask manufactured from the mask blank of the present invention (for example, the reflective mask 60) suffers less damage to the conductive film. Therefore, it does not affect the substrate adsorption force by the electrostatic chuck or the pattern transfer accuracy. Moreover, in the manufacture of semiconductor devices using this reflective mask, good substrate adsorption force by the electrostatic chuck can be obtained by performing pattern transfer using this reflective mask with less damage to the conductive film. Therefore, high-precision pattern transfer can be performed without causing transfer position shift during exposure.

[0132] The embodiments of the present invention will be described in more detail below with reference to examples. (Example 1) As a substrate, SiO ２ -TiO ２ A glass substrate was prepared. This glass substrate was 6 inches square, measuring approximately 152.0 mm × 152.0 mm in size and approximately 6.35 mm in thickness. By mechanical polishing, this glass substrate had a smooth surface with a root mean square roughness (Rq) of 0.25 nm and a flatness of less than 100 nm. The surface roughness was measured using an atomic force microscope (AFM), with a measurement area of ​​1 μm × 1 μm. Hereafter, this glass substrate will be simply referred to as the substrate.

[0133] First, a conductive film made of TaPd was formed on the back surface (second main surface) of the substrate. The substrate was placed in a sputtering apparatus, and a TaPd film with a thickness of 70 nm was formed using a target containing Ta and Pd, and argon (Ar) as the sputtering gas. The composition ratio of the TaPd film was Ta:Pd = 80 atomic%:20 atomic%.

[0134] Next, on the substrate surface opposite to the conductive film (first main surface), an ion beam sputtering apparatus was used to layer Si films (thickness: 4.2 nm) and Mo films (thickness: 2.8 nm) in 40 cycles, with each cycle consisting of a Si film (thickness: 4 nm) as the final layer. Furthermore, a protective film made of Ru (thickness: 2.5 nm) was deposited on the Si film furthest from the substrate surface to obtain a substrate with a multilayer reflective film.

[0135] Next, using a DC magnetron sputtering apparatus, an absorber film consisting of a TaBO film (thickness: 4 nm) as the lower absorber layer and a PtTa film (thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate. For the formation of the TaBO film, a target containing Ta and B and a mixed gas of argon and oxygen were used as the sputtering gas. The composition ratio of the TaBO film was Ta:B:O = 40 atomic%:8 atomic%:52 atomic%. The PtTa film was formed by DC magnetron sputtering using a PtTa target and argon (Ar) as the sputtering gas. The composition ratio of the PtTa film was Pt:Ta = 60 atomic%:40 atomic%. A reflective mask blank was obtained in this manner.

[0136] Next, a reflective mask was fabricated using the reflective mask blank described above. First, an electron beam resist was applied to the reflective mask blank and baked to form a resist film. A predetermined mask pattern was drawn onto this resist film using an electron beam, and then developed to form a resist pattern.

[0137] Under conditions of a pressure Pch of 4 mTorr and a temperature Tch of 60°C in the etching chamber, the PtTa film, which is the first film and the upper layer of the absorber, was etched using chlorine gas as the halogen, with this resist pattern as a mask.

[0138] The conductive film in this embodiment contains Pd, but Pd chloride PdCl ２ The normal boiling point T １ This was not listed in the database, etc. Therefore, in this example, the normal boiling point T １ Instead of PdCl ２We decided to calculate the standard boiling point Tb using the melting point of [the substance]. (Normal boiling point T) １ PdCl ２ The melting point of is 952 (K). PdCl was calculated using this melting point. ２ The standard boiling point Tb was 953 (K). The melting point is lower than the normal boiling point. Therefore, the standard boiling point Tb calculated using the melting point instead of the normal boiling point will also be lower than the actual standard boiling point. Consequently, it is clear that the vapor pressure Pm calculated using the melting point instead of the normal boiling point will also be lower than the actual vapor pressure Pm. Therefore, in this embodiment, the PdCl derived from the conductive film at a temperature of 60°C during etching of the absorber film is... ２ The vapor pressure Pm is 4.62 × 10⁻⁶ ―６ It was less than or equal to mTorr. As mentioned above, following the procedure for deriving the vapor pressure curve, PdCl ２ The vapor pressure curve was derived, and from the obtained vapor pressure curve, the vapor pressure curve of PdCl at a temperature of 60°C was used. ２ The vapor pressure Pm was calculated. Therefore, in this embodiment, during etching of the PtTa film as the first film, which is the upper layer of the absorber, the PdCl derived from the conductive film at the etching temperature Tch of 60°C was calculated. ２ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the PtTa film as the absorber upper layer under the above etching conditions was 0.07 nm / second. After etching of the PtTa film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the PtTa film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the PtTa film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0139] Furthermore, CF as a fluorine-based gas ４The TaBO film, which serves as the absorber underlayer, was etched with a mixed gas of and He. This formed an absorber film pattern on the protective film. Furthermore, the resist pattern on the absorber film pattern was removed to obtain a reflective mask. The TaBO film, which serves as the absorber underlayer, has a small film thickness. Also, CF ４ When a mixed gas of ethanol and He was used, the etching rate of the TaBO film was sufficiently large. Therefore, the effect of etching the TaBO film as the absorber underlayer on the conductive film was negligibly small. The same was true in other examples and comparative examples in which the TaBO film was used as the absorber underlayer. The reflective mask obtained in this example was set in the exposure apparatus, and a pattern transfer was performed onto the semiconductor substrate on which the resist film was formed. As a result, the reflective mask was well supported by the electrostatic chuck via the conductive film, and high-precision pattern transfer could be performed without causing misalignment of the transfer position during exposure.

[0140] (Example 2) A conductive film made of TaIr was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a TaIr film with a thickness of 70 nm was formed using a target containing Ta and Ir, and argon (Ar) as the sputtering gas. The composition ratio of the TaIr film was Ta:Ir = 80 atomic%:20 atomic%.

[0141] Next, a multilayer reflective film and a protective film were sequentially deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0142] Next, in the same manner as in Example 1, an absorber film consisting of a laminated film of a TaBO film (film thickness: 4 nm) as the lower absorber layer and a PtTa film (film thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate using a DC magnetron sputtering apparatus. A reflective mask blank was obtained in this manner.

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

[0144] The conductive film in this embodiment contains Ir, but also Ir chloride IrCl ４The normal boiling point T １ This was not listed in the database, etc. Therefore, in this example, the normal boiling point T １ Instead of IrCl ４ We decided to calculate the standard boiling point Tb using the melting point of [the substance]. (Normal boiling point T) １ IrCl ４ The melting point of is 973 (K). Using this melting point, IrCl was calculated. ４ The standard boiling point Tb was 973 (K). The melting point is lower than the normal boiling point. Therefore, the standard boiling point Tb calculated using the melting point instead of the normal boiling point will also be lower than the actual standard boiling point. Consequently, it is clear that the vapor pressure Pm calculated using the melting point instead of the normal boiling point will also be lower than the actual vapor pressure Pm. Therefore, in this embodiment, the IrCl derived from the conductive film at a temperature of 60°C during etching of the absorber film is... ４ The vapor pressure Pm is 1.75 × 10⁻⁶ ―６ It was less than or equal to mTorr. As mentioned above, following the procedure for deriving the vapor pressure curve, IrCl ４ The vapor pressure curve was derived, and from the obtained vapor pressure curve, the vapor pressure curve of IrCl at a temperature of 60°C was used. ４ The vapor pressure Pm was calculated. Therefore, in this embodiment, during etching of the PtTa film as the first film, which is the upper layer of the absorber, the IrCl from the conductive film at the etching temperature Tch of 60°C was calculated. ４ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the PtTa film as the absorber upper layer under the above etching conditions was 0.07 nm / second. After etching of the PtTa film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the PtTa film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the PtTa film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0145] The reflective mask obtained in this embodiment was set in the exposure apparatus, and a pattern transfer was performed onto the semiconductor substrate on which the resist film had been formed. As a result, the reflective mask was well supported by the electrostatic chuck via the conductive film, and high-precision pattern transfer was possible without any shift in the transfer position during exposure.

[0146] (Example 3) A conductive film made of TaY was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a TaY film with a thickness of 70 nm was formed using a target containing Ta and Y and argon (Ar) as the sputtering gas. The composition ratio of the TaY film was Ta:Y = 97 atomic%:3 atomic%.

[0147] Next, a multilayer reflective film and a protective film were sequentially deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0148] Next, in the same manner as in Example 1, an absorber film consisting of a laminated film of a TaBO film (film thickness: 4 nm) as the lower absorber layer and a PtTa film (film thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate using a DC magnetron sputtering apparatus. A reflective mask blank was obtained in this manner.

[0149] Next, a reflective mask was fabricated using the above-mentioned reflective mask blank in the same manner as in Example 1.

[0150] The conductive film in this embodiment contains Y, and YCl ３ The normal boiling point T １ The temperature was 1755 (K), and the standard boiling point Tb was 1474 (K). Therefore, in this embodiment, the YCl derived from the conductive film at a temperature of 60°C during etching of the absorber film was ３ The vapor pressure Pm is 3.59 × 10⁻⁶ ―１８ It was mTorr. Furthermore, following the procedure for deriving the vapor pressure curve mentioned above, YCl ３ The vapor pressure curve was derived, and from the obtained vapor pressure curve, YCl at a temperature of 60°C was used. ３The vapor pressure Pm was calculated. Therefore, in this embodiment, during etching of the PtTa film as the first film, which is the upper layer of the absorber, the YCl from the conductive film at the etching temperature Tch of 60°C was calculated. ３ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the PtTa film as the absorber upper layer under the above etching conditions was 0.07 nm / second. After etching of the PtTa film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the PtTa film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the PtTa film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0151] The reflective mask obtained in this embodiment was set in the exposure apparatus, and a pattern transfer was performed onto the semiconductor substrate on which the resist film had been formed. As a result, the reflective mask was well supported by the electrostatic chuck via the conductive film, and high-precision pattern transfer was possible without any shift in the transfer position during exposure.

[0152] (Example 4) A conductive film made of TaRh was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a TaRh film with a thickness of 70 nm was formed using a target containing Ta and Rh and argon (Ar) as the sputtering gas. The composition ratio of the TaRh film was Ta:Rh = 80 atomic%:20 atomic%.

[0153] Next, a multilayer reflective film and a protective film were sequentially deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0154] Next, in the same manner as in Example 1, an absorber film consisting of a laminated film of a TaBO film (film thickness: 4 nm) as the lower absorber layer and a PtTa film (film thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate using a DC magnetron sputtering apparatus. A reflective mask blank was obtained in this manner.

[0155] Next, a reflective mask was fabricated using the above-mentioned reflective mask blank in the same manner as in Example 1.

[0156] The conductive film in this embodiment contains Rh, and Rh chloride RhCl ３ The normal boiling point T １ The temperature was 990 (K), and the standard boiling point Tb was 989 (K). Therefore, in this embodiment, the RhCl derived from the conductive film at the etching temperature of the absorber film at 60°C was ３ The vapor pressure Pm is 8.05 × 10 ―７ It was mTorr. Furthermore, following the procedure for deriving the vapor pressure curve mentioned above, RhCl ３ The vapor pressure curve was derived, and from the obtained vapor pressure curve, the RhCl at a temperature of 60°C was used. ３ The vapor pressure Pm was calculated. Therefore, in this embodiment, during etching of the PtTa film as the first film, which is the upper layer of the absorber, the RhCl from the conductive film at the etching temperature Tch of 60°C was calculated. ３ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the PtTa film as the absorber upper layer under the above etching conditions was 0.07 nm / second. After etching of the PtTa film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the PtTa film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the PtTa film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0157] The reflective mask obtained in this embodiment was set in the exposure apparatus, and a pattern transfer was performed onto the semiconductor substrate on which the resist film had been formed. As a result, the reflective mask was well supported by the electrostatic chuck via the conductive film, and high-precision pattern transfer was possible without any shift in the transfer position during exposure.

[0158] (Example 5) A conductive film made of CrY was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a CrY film with a thickness of 70 nm was formed using a target containing Cr and Y, and argon (Ar) as the sputtering gas. The composition ratio of the CrY film was Cr:Y = 88 atomic%:12 atomic%.

[0159] Next, a multilayer reflective film and a protective film were sequentially deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0160] Next, in the same manner as in Example 1, an absorber film consisting of a laminated film of a TaBO film (film thickness: 4 nm) as the lower absorber layer and a PtTa film (film thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate using a DC magnetron sputtering apparatus. A reflective mask blank was obtained in this manner.

[0161] Next, a reflective mask was fabricated using the above-mentioned reflective mask blank in the same manner as in Example 1.

[0162] The conductive film in this embodiment contains Y, and YCl ３ The normal boiling point T １ The temperature was 1755 (K), and the standard boiling point Tb was 1474 (K). Therefore, in this embodiment, the YCl derived from the conductive film at a temperature of 60°C during etching of the absorber film was ３ The vapor pressure Pm is 3.59 × 10⁻⁶ ―１８ It was mTorr. Furthermore, following the procedure for deriving the vapor pressure curve mentioned above, YCl ３ The vapor pressure curve was derived, and from the obtained vapor pressure curve, YCl at a temperature of 60°C was used. ３The vapor pressure Pm was calculated. Therefore, in this embodiment, during etching of the PtTa film as the upper layer of the absorber, the YCl derived from the conductive film at the etching temperature Tch of 60°C was calculated. ３ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the PtTa film as the absorber upper layer under the above etching conditions was 0.07 nm / second. After etching of the PtTa film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the PtTa film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the PtTa film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0163] The reflective mask obtained in this embodiment was set in the exposure apparatus, and a pattern transfer was performed onto the semiconductor substrate on which the resist film had been formed. As a result, the reflective mask was well supported by the electrostatic chuck via the conductive film, and high-precision pattern transfer was possible without any shift in the transfer position during exposure.

[0164] (Example 6) A conductive film made of CrPd was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a CrPd film with a thickness of 70 nm was formed using a target containing Cr and Pd, and argon (Ar) as the sputtering gas. The composition ratio of the CrPd film was Cr:Pd = 97 atomic%:3 atomic%.

[0165] Next, a multilayer reflective film and a protective film were sequentially deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0166] Subsequently, in the same manner as in Example 1, a TaBO film (film thickness: 4 nm) as an absorber lower layer was formed on the protective film of the substrate with the multilayer reflective film using a DC magnetron sputtering apparatus. Further, a RuCrON film (film thickness: 30 nm) as an absorber upper layer was formed on the TaBO film as the absorber lower layer. The RuCrON film was formed by DC magnetron sputtering using a target containing Ru and Cr, and a mixed gas of argon (Ar), oxygen and nitrogen as a sputtering gas. The composition ratio of the RuCrON film was Ru:Cr:O:N = 73 atomic%:9 atomic%:12 atomic%:6 atomic%. A reflective mask blank was obtained as described above.

[0167] Next, a reflective mask was produced using the above reflective mask blank. First, in the same manner as in Example 1, a resist pattern was formed on the reflective mask blank. Under the conditions where the pressure Pch in the etching chamber was 4 mTorr and the temperature Tch was 60°C, the absorber film was etched using this resist pattern as a mask to form an absorber film pattern on the protective film. Specifically, the RuCrON film as the first film, which is the absorber upper layer, was etched using a chlorine-based gas. The chlorine-based gas contains Cl as a halogen ２ and O ２ is a mixed gas with Cl ２ and O ２ the flow rate ratio (%) of Cl ２ :O ２ = 90:10.

[0168] Since the conductive film of this example contains Pd, similarly to Example 1, the normal boiling point T １ the melting point of PdCl was used instead ２ In this example, PdCl derived from the conductive film at a temperature of 60°C during etching of the absorber upper layer (first film) ２ the vapor pressure Pm of was 4.62×10 ―６ mTorr or less. Therefore, in this example, in the etching of the RuCrON film as the first film which is the absorber upper layer, PdCl derived from the conductive film at an etching temperature Tch of 60°C ２The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the RuCrON film as the absorber upper layer under the above etching conditions was 0.04 nm / second. After etching of the RuCrON film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the RuCrON film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the RuCrON film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0169] Furthermore, CF ４ An absorber film pattern was formed by etching the TaBO film, which served as the underlying layer of the absorber, using a mixed gas of gas and He gas. Furthermore, the resist pattern on the absorber film pattern was removed to obtain a reflective mask. The reflective mask obtained in this embodiment was set in an exposure apparatus, and the 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, and high-precision pattern transfer was possible without any shift in the transfer position during exposure.

[0170] (Example 7) A conductive film made of TaY was formed on the back surface of a substrate prepared in the same manner as in Example 1. In the same manner as in Example 3, the substrate was placed in a sputtering apparatus, and a TaY film with a thickness of 70 nm was formed using a target containing Ta and Y and argon (Ar) as the sputtering gas. The composition ratio of the TaY film was Ta:Y = 80 atomic%:20 atomic%.

[0171] Next, a multilayer reflective film was formed on the substrate surface opposite to the above-mentioned conductive film in the same manner as in Example 1. Further, a protective film made of RuRhCrN (film thickness: 2.5 nm) was formed on the Si film farthest from the substrate surface of the multilayer reflective film. For forming the RuRhCrN film, a target containing Ru, Rh, and Cr, and a mixed gas of argon and nitrogen as a sputtering gas were used. The composition ratio of the RuRhCrN film was Ru:Rh:Cr:N = 60 atomic%: 30 atomic%: 6 atomic%: 4 atomic%. A substrate with a multilayer reflective film was obtained as described above.

[0172] Subsequently, using a DC magnetron sputtering apparatus, an absorber film composed of a laminated film of a CrN film (film thickness: 4 nm) as an absorber lower layer and a PtRu film (film thickness: 30 nm) as an absorber upper layer was formed on the protective film of the above-mentioned substrate with a multilayer reflective film. For forming the CrN film, a Cr target and a mixed gas of argon and nitrogen as a sputtering gas were used. The composition ratio of the CrN film was Cr:N = 90 atomic%: 10 atomic%. For the PtRu film, a target containing Pt and Ru, and argon (Ar) gas as a sputtering gas were used. The composition ratio of the PtRu film was Pt:Ru = 45 atomic%: 55 atomic%. A reflective mask blank was obtained as described above.

[0173] Next, a reflective mask was produced using the above-mentioned reflective mask blank. First, in the same manner as in Example 1, a resist pattern was formed on the reflective mask blank. Under the conditions where the pressure Pch in the etching chamber was 4 mTorr and the temperature Tch was 60°C, the PtRu film as the first film, which is the absorber upper layer, was etched using a fluorine-based gas with this resist pattern as a mask. The fluorine-based gas is CF ４ gas and O ２ It is a mixed gas with gas, and CF ４ and O ２ The flow rate ratio (%) of CF ４ : O ２ = 90:10.

[0174] The conductive film of this example contains Y, and YF ３ has a normal boiling point T １The temperature was 2503 (K), and the standard boiling point Tb was 1615 (K). Therefore, in this embodiment, the YF from the conductive film at a temperature of 60°C during etching of the absorber film was ３ The vapor pressure Pm is 1.10 × 10 ―２２ It was mTorr. Furthermore, following the procedure for deriving the vapor pressure curve mentioned above, YF ３ The vapor pressure curve was derived, and from the obtained vapor pressure curve, YF at a temperature of 60°C ３ The vapor pressure Pm was calculated. Therefore, in this embodiment, in etching the PtRu film as the first film, which is the upper layer of the absorber, the YF from the conductive film at etching temperature Tch 60°C was calculated. ３ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the PtRu film as the absorber upper layer under the above etching conditions was 0.09 nm / second. After etching of the PtRu film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the PtRu film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the PtRu film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0175] Furthermore, Cl ２ and O ２ The CrN film, which serves as the underlying layer of the absorber, was etched using a mixed gas. This formed an absorber film pattern. Furthermore, the resist pattern on the absorber film pattern was removed to obtain a reflective mask. The CrN film, which serves as the underlying layer of the absorber, has a small film thickness. Also, Cl ２ and O ２When a mixed gas was used, the etching rate of the CrN film was sufficiently large. Therefore, the effect of etching the CrN film as the absorber underlayer on the conductive film was negligibly small. The same was true in the examples and comparative examples in which the CrN film was used as the absorber underlayer. The reflective mask obtained in this example was set in the exposure apparatus, and a pattern transfer was performed onto the semiconductor substrate on which the resist film was formed. As a result, the reflective mask was well supported by the electrostatic chuck via the conductive film, and high-precision pattern transfer could be performed without causing misalignment of the transfer position during exposure.

[0176] (Example 8) A conductive film made of TaZr was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a TaZr film with a thickness of 70 nm was formed using a target containing Ta and Zr and argon (Ar) as the sputtering gas. The composition ratio of the TaZr film was Ta:Zr = 80 atomic%:20 atomic%.

[0177] Next, a multilayer reflective film was deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1. Furthermore, in the same manner as in Example 7, a protective film made of RuRhCrN (thickness: 2.5 nm) was deposited on the Si film furthest from the substrate surface of the multilayer reflective film to obtain a substrate with a multilayer reflective film.

[0178] Next, using a DC magnetron sputtering apparatus, a CrN film (thickness: 4 nm) was formed on the protective film of the multilayer reflective substrate in the same manner as in Example 7, as the lower layer of the absorber. Furthermore, a PtRuTaN film (thickness: 30 nm) was formed on the CrN film as the upper layer of the absorber, thereby forming an absorber film with a layered structure. For the PtRuTaN film, a target containing Pt, Ru, and Ta was used, and a mixed gas of argon (Ar) and nitrogen was used as the sputtering gas. The composition ratio of the PtRuTaN film was Pt:Ru:Ta:N = 43 atomic%:40 atomic%:10 atomic%:7 atomic%. A reflective mask blank was obtained in the manner described above.

[0179] Next, a reflective mask was fabricated using the reflective mask blank described above. First, a resist pattern was formed on the reflective mask blank in the same manner as in Example 1. Under conditions of a pressure Pch of 4 mTorr and a temperature Tch of 60°C in the etching chamber, the absorber film was etched using this resist pattern as a mask to form an absorber film pattern on the protective film. Specifically, a fluorine-based gas was used to etch the PtRuTaN film, which is the first film and the upper layer of the absorber. The fluorine-based gas described above is CF containing fluorine as a halogen. ４ Gas and O ２ It is a gas mixture with CF ４ and O ２ The flow rate ratio (%) is CF ４ : O ２ The ratio was 90:10.

[0180] The conductive film in this embodiment contains Zr, and ZrF ４ The normal boiling point T １ The temperature was 1185 (K), and the standard boiling point Tb was 1157 (K). Therefore, in this embodiment, the ZrF from the conductive film at a temperature of 60°C during etching of the absorber film was ４ The vapor pressure Pm is 1.17 × 10⁻⁶ ―１０ It was mTorr. Furthermore, following the procedure for deriving the vapor pressure curve mentioned above, ZrF ４ The vapor pressure curve was derived, and from the obtained vapor pressure curve, ZrF at a temperature of 60°C was used. ４ The vapor pressure Pm was calculated. Therefore, in this embodiment, during etching of the PtRuTaN film as the first film, which is the upper layer of the absorber, the ZrF from the conductive film at the etching temperature Tch 60°C was calculated. ４The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the PtRuTaN film as the absorber upper layer under the above etching conditions was 0.09 nm / second. After etching of the PtRuTaN film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the PtRuTaN film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the PtRuTaN film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0181] Furthermore, the CrN film beneath the absorber was etched in the same manner as in Example 7. This formed an absorber film pattern. Next, the resist pattern on the absorber film pattern was removed to obtain a reflective mask. The reflective mask obtained in this example was set in an exposure apparatus, and the 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, and high-precision pattern transfer was possible without any misalignment of the transfer position during exposure.

[0182] (Example 9) A conductive film made of TaY was formed on the back surface of a substrate prepared in the same manner as in Example 1. In the same manner as in Example 3, the substrate was placed in a sputtering apparatus, and a TaY film with a thickness of 70 nm was formed using a target containing Ta and Y and argon (Ar) as the sputtering gas. The composition ratio of the TaY film was Ta:Y = 80 atomic%:20 atomic%.

[0183] Next, a multilayer reflective film was deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1. Furthermore, in the same manner as in Example 7, a protective film made of RuRhCrN (thickness: 2.5 nm) was deposited on the Si film furthest from the substrate surface of the multilayer reflective film to obtain a substrate with a multilayer reflective film.

[0184] Next, using a DC magnetron sputtering apparatus, a CrN film (thickness: 4 nm) was formed on the protective film of the multilayer reflective film substrate in the same manner as in Example 7, as the lower layer of the absorber. Furthermore, an IrTaO film (thickness: 30 nm) was formed on the CrN film as the upper layer of the absorber, thereby forming an absorber film with a layered structure. The IrTaO film was formed using a target containing Ir and Ta, and a mixed gas of argon and oxygen as the sputtering gas (flow rate ratio (%) Ar:O ２ A ratio of 90:10 was used. The composition ratio of the IrTaO film was Ir:Ta:O = 70 atomic%:10 atomic%:20 atomic%. A reflective mask blank was obtained in the manner described above.

[0185] Next, a reflective mask was fabricated using the reflective mask blank described above. First, a resist pattern was formed on the reflective mask blank in the same manner as in Example 1. Under conditions of a pressure Pch of 4 mTorr and a temperature Tch of 60°C in the etching chamber, the absorber film was etched using this resist pattern as a mask to form an absorber film pattern on the protective film. Specifically, the IrTaO film, which is the first film and the upper layer of the absorber, was etched using a fluorine-based gas. The fluorine-based gas described above is CF containing fluorine as a halogen. ４ Gas and O ２ It is a gas mixture with CF ４ and O ２ The flow rate ratio (%) is CF ４ : O ２ The ratio was 90:10.

[0186] The conductive film in this embodiment contains Y, and YF ３ The normal boiling point T １ The temperature was 2503 (K), and the standard boiling point Tb was 1615 (K). Therefore, in this embodiment, the YF from the conductive film at a temperature of 60°C during etching of the absorber film was ３ The vapor pressure Pm is 1.10 × 10 ―２２ It was mTorr. Furthermore, following the procedure for deriving the vapor pressure curve mentioned above, YF ３ The vapor pressure curve was derived, and from the obtained vapor pressure curve, YF at a temperature of 60°C ３The vapor pressure Pm was calculated. Therefore, in this embodiment, in etching the IrTaO film as the first film, which is the upper layer of the absorber, the YF from the conductive film at etching temperature Tch 60°C ３ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the IrTaO film as the absorber upper layer under the above etching conditions was 0.15 nm / second. After etching of the IrTaO film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the IrTaO film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the IrTaO film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0187] Furthermore, the CrN film beneath the absorber was etched in the same manner as in Example 7. This formed an absorber film pattern. Next, the resist pattern on the absorber film pattern was removed to obtain a reflective mask. The reflective mask obtained in this example was set in an exposure apparatus, and the 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, and high-precision pattern transfer was possible without any misalignment of the transfer position during exposure.

[0188] (Example 10) A conductive film consisting of a laminated film of a TaN film (thickness: 60 nm) as the conductive film underlayer and a Y film (thickness: 10 nm) as the conductive film upper layer was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and for the deposition of the TaN film, a Ta target and a mixed gas of argon and nitrogen as the sputtering gas (flow rate ratio (%) Ar:N ２ A ratio of 90:10 was used. The composition ratio of the TaN film was Ta:N = 74 atomic%:26 atomic%. In addition, a Y target and argon (Ar) as the sputtering gas were used to deposit the Y film.

[0189] Next, a multilayer reflective film was deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1. Furthermore, in the same manner as in Example 7, a protective film made of RuRhCrN (thickness: 2.5 nm) was deposited on the Si film furthest from the substrate surface of the multilayer reflective film to obtain a substrate with a multilayer reflective film.

[0190] Next, using a DC magnetron sputtering apparatus, a CrN film (thickness: 4 nm) was formed on the protective film of the multilayer reflective substrate in the same manner as in Example 7, as the lower layer of the absorber. Furthermore, a RuW film (thickness: 30 nm) was formed on the CrN film as the upper layer of the absorber, thereby forming an absorber film with a layered structure. For the deposition of the RuW film, a target containing Ru and W and argon gas were used as the sputtering gas. The composition ratio of the RuW film was Ru:W = 25 atomic%:75 atomic%. A reflective mask blank was obtained in the manner described above.

[0191] Next, a reflective mask was fabricated using the reflective mask blank described above. First, a resist pattern was formed on the reflective mask blank in the same manner as in Example 1. Under conditions of a pressure Pch of 4 mTorr and a temperature Tch of 60°C in the etching chamber, the absorber film was etched using this resist pattern as a mask to form an absorber film pattern on the protective film. Specifically, a fluorine-based gas was used to etch the RuW film, which is the first film and the upper layer of the absorber. The fluorine-based gas described above is CF containing fluorine as a halogen. ４ It is a mixed gas of gas and He gas, CF ４ The flow rate ratio (%) of He is CF ４ The ratio of He to He was 60:40.

[0192] The conductive film in this embodiment includes a layer made of Y, and YF ３ The normal boiling point T １ The temperature was 2503 (K), and the standard boiling point Tb was 1615 (K). Therefore, in this embodiment, the YF from the conductive film (upper layer) at a temperature of 60°C during etching of the absorber film was ３ The vapor pressure Pm is 1.10 × 10 ―２２It was mTorr. Furthermore, following the procedure for deriving the vapor pressure curve mentioned above, YF ３ The vapor pressure curve was derived, and from the obtained vapor pressure curve, YF at a temperature of 60°C ３ The vapor pressure Pm was calculated. Therefore, in this embodiment, in etching the RuW film as the first film, which is the upper layer of the absorber, the YF from the conductive film at etching temperature Tch 60°C ３ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the RuW film as the absorber upper layer under the above etching conditions was 0.10 nm / second. After etching of the RuW film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the RuW film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the RuW film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0193] Furthermore, the CrN film beneath the absorber was etched in the same manner as in Example 7. This formed an absorber film pattern. Next, the resist pattern on the absorber film pattern was removed to obtain a reflective mask. The reflective mask obtained in this example was set in an exposure apparatus, and the 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, and high-precision pattern transfer was possible without any misalignment of the transfer position during exposure.

[0194] (Example 11) A conductive film made of a Y film was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a Y film with a thickness of 70 nm was formed using a Y target and argon (Ar) as the sputtering gas.

[0195] Next, a multilayer reflective film was deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1. Furthermore, in the same manner as in Example 7, a protective film made of RuRhCrN (thickness: 2.5 nm) was deposited on the Si film furthest from the substrate surface of the multilayer reflective film to obtain a substrate with a multilayer reflective film.

[0196] Next, using a DC magnetron sputtering apparatus, a CrN film (thickness: 4 nm) was formed on the protective film of the multilayer reflective substrate in the same manner as in Example 7, as the lower layer of the absorber. Furthermore, a PtTaN film (thickness: 30 nm) was formed on the CrN film as the upper layer of the absorber, thereby forming an absorber film with a layered structure. For the PtTaN film, a target containing Pt and Ta was used, and a mixed gas of argon and nitrogen was used as the sputtering gas. The composition ratio of the PtTaN film was Pt:Ta:N = 73 atomic%:21 atomic%:6 atomic%. A reflective mask blank was obtained in this manner.

[0197] Next, a reflective mask was fabricated using the reflective mask blank described above. First, a resist pattern was formed on the reflective mask blank in the same manner as in Example 1. Using this resist pattern as a mask, the absorber film was etched under conditions of a pressure Pch of 4 mTorr and a temperature Tch of 60°C in the etching chamber to form an absorber film pattern on the protective film. Specifically, a fluorine-based gas was used to etch the PtTaN film, which is the first film and the upper layer of the absorber. The fluorine-based gas described above is CF containing fluorine as a halogen. ４ Gas and O ２ It is a gas mixture with CF ４ and O ２ The flow rate ratio (%) is CF ４ : O ２ The ratio was 90:10.

[0198] The conductive film in this embodiment consists of Y and YF ３ The normal boiling point T １ The temperature was 2503 (K), and the standard boiling point Tb was 1615 (K). Therefore, in this embodiment, the YF from the conductive film at a temperature of 60°C during etching of the absorber film was ３ The vapor pressure Pm is 1.10 × 10―２２ It was mTorr. Furthermore, following the procedure for deriving the vapor pressure curve mentioned above, YF ３ The vapor pressure curve was derived, and from the obtained vapor pressure curve, YF at a temperature of 60°C ３ The vapor pressure Pm was calculated. In this example, during etching of the PtTaN film as the first film, which is the upper layer of the absorber, the YF from the conductive film at etching temperature Tch 60°C was calculated. ３ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the PtTaN film as the absorber upper layer under the above etching conditions was 0.16 nm / second. After etching of the PtTaN film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the PtTaN film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the PtTaN film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0199] Furthermore, the CrN film beneath the absorber was etched in the same manner as in Example 7. This formed an absorber film pattern. Next, the resist pattern on the absorber film pattern was removed to obtain a reflective mask. The reflective mask obtained in this example was set in an exposure apparatus, and the 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, and high-precision pattern transfer was possible without any misalignment of the transfer position during exposure.

[0200] (Example 12) A conductive film consisting of a laminated film of a TaN film (thickness: 60 nm) as the conductive underlayer and a Pd film (thickness: 10 nm) as the conductive upper layer was formed on the back surface of a substrate prepared in the same manner as in Example 1. The TaN film was formed in the same manner as in Example 10. A Pd target and argon (Ar) as the sputtering gas were used to form the Pd film.

[0201] Next, a multilayer reflective film was deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1. Furthermore, in the same manner as in Example 7, a protective film made of RuRhCrN (thickness: 2.5 nm) was deposited on the Si film furthest from the substrate surface of the multilayer reflective film to obtain a substrate with a multilayer reflective film.

[0202] Next, using a DC magnetron sputtering apparatus, a CrN film (thickness: 4 nm) was formed on the protective film of the multilayer reflective substrate in the same manner as in Example 7, as the lower layer of the absorber. Furthermore, a RuTa film (thickness: 30 nm) was formed on the CrN film as the upper layer of the absorber, thereby forming an absorber film with a layered structure. For the deposition of the RuTa film, a target containing Ru and Ta and argon gas were used as the sputtering gas. The composition ratio of the RuTa film was Ru:Ta = 45 atomic%:55 atomic%. A reflective mask blank was obtained in the manner described above.

[0203] Next, a reflective mask was fabricated using the reflective mask blank described above. First, a resist pattern was formed on the reflective mask blank in the same manner as in Example 1. Under conditions of a pressure Pch of 4 mTorr and a temperature Tch of 60°C in the etching chamber, the absorber film was etched using this resist pattern as a mask to form an absorber film pattern on the protective film. Specifically, a fluorine-based gas was used to etch the RuTa film, which is the first film and the upper layer of the absorber. The fluorine-based gas described above is CF containing fluorine as a halogen. ４ Gas and O ２ It is a gas mixture with CF ４ and O ２ The flow rate ratio (%) is CF ４ : O ２ The ratio was 90:10.

[0204] The conductive film in this embodiment includes a layer made of Pd, but PdF ２ The normal boiling point T １ This was not listed in the database, etc. Therefore, in this example, the normal boiling point T １ PdF ２ We decided to calculate the standard boiling point Tb using the melting point of [the substance]. (Normal boiling point T) １PdF ２ The melting point is 1225 (K). PdF was calculated using this melting point. ２ The standard boiling point Tb was 1188 (K). The melting point is lower than the normal boiling point. Therefore, the standard boiling point Tb calculated using the melting point instead of the normal boiling point will also be lower than the actual standard boiling point. Consequently, it is clear that the vapor pressure Pm calculated using the melting point instead of the normal boiling point will also be lower than the actual vapor pressure Pm. Therefore, in this embodiment, the PdF derived from the conductive film (upper layer) at a temperature of 60°C during etching of the absorber film is ２ The vapor pressure Pm is 2.83 × 10⁻⁶ ―１１ It was less than or equal to mTorr. As mentioned above, following the procedure for deriving the vapor pressure curve, PdF ２ The vapor pressure curve was derived, and from the obtained vapor pressure curve, PdF at a temperature of 60°C was used. ２ The vapor pressure Pm was calculated. Therefore, in this embodiment, during etching of the RuTa film as the first film, which is the upper layer of the absorber, the PdF originating from the conductive film at etching temperature Tch 60°C was calculated. ２ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the RuTa film as the absorber upper layer under the above etching conditions was 0.05 nm / second. After etching of the RuTa film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching of the RuTa film as the absorber upper layer under the above etching conditions was 20% or less of the film thickness at the outer periphery of the conductive film before etching of the RuTa film. In other words, even when a difficult-to-etch material was used for the absorber film, it was possible to suppress the damage to the conductive film caused by etching of the absorber film during the manufacturing process of the reflective mask.

[0205] Furthermore, the CrN film beneath the absorber was etched in the same manner as in Example 7. This formed an absorber film pattern. Next, the resist pattern on the absorber film pattern was removed to obtain a reflective mask. The reflective mask obtained in this example was set in an exposure apparatus, and the 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, and high-precision pattern transfer was possible without any misalignment of the transfer position during exposure.

[0206] (Example 13) A conductive film made of a TaPd film was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a TaPd film with a thickness of 70 nm was formed using a target containing Ta and Pd and argon (Ar) as the sputtering gas. The composition ratio of the TaPd film was Ta:Pd = 90 atomic%:10 atomic%.

[0207] Next, a multilayer reflective film was deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1. Furthermore, in the same manner as in Example 7, a protective film made of RuRhCrN (film thickness: 2.5 nm) was deposited on the Si film furthest from the substrate surface of the multilayer reflective film to obtain a substrate with a multilayer reflective film.

[0208] Next, in the same manner as in Example 1, an absorber film consisting of a laminated film of a TaBO film (film thickness: 4 nm) as the lower absorber layer and a PtTa film (film thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate using a DC magnetron sputtering apparatus. A reflective mask blank was obtained in this manner.

[0209] Next, in the same manner as in Example 1, an absorber film pattern was formed by etching the absorber film of the reflective mask blank. Furthermore, in order to form a light-shielding region, the protective film as the first film was etched with a fluorine-based gas under conditions of a pressure Pch of 4 mTorr and a temperature Tch of 60°C in the etching chamber. The fluorine-based gas was CF containing fluorine as a halogen. ４ It is a mixed gas of gas and He gas, CF ４ The flow rate ratio (%) of He is CF４ The ratio of He to He was 60:40.

[0210] Since the conductive film in this embodiment contains Pd, the normal boiling point T is the same as in Example 12. １ PdF ２ The melting point of the above-mentioned PdF was used. In this example, the PdF derived from the conductive film at a temperature of 60°C during etching of the protective film was used. ２ The vapor pressure Pm is 2.83 × 10⁻⁶, similar to Example 12. ―１１ It was less than or equal to mTorr. Therefore, in this embodiment, in etching the protective film as the first film, the PdF derived from the conductive film at etching temperature Tch 60°C ２ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the RuRhCrN protective film was 0.01 nm / second. After etching of the absorber film and protective film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. Also, the reduction in film thickness at the outer periphery of the conductive film after etching of the absorber film and protective film was less than 20% of the film thickness at the outer periphery of the conductive film before etching. In other words, even when difficult-to-etch materials were used for the absorber film and protective film, damage to the conductive film due to etching of the absorber film and protective film during the manufacturing process of the reflective mask could be suppressed.

[0211] Furthermore, a light-shielding region was formed by etching the multilayer reflective film. Next, the resist pattern on the absorber film pattern was removed to obtain a reflective mask. The reflective mask obtained in this embodiment was set in the exposure apparatus, and the pattern was transferred onto the semiconductor substrate on which the resist film had been formed. As a result, the reflective mask was well supported by the electrostatic chuck via the conductive film, and high-precision pattern transfer was possible without any shift in the transfer position during exposure.

[0212] (Example 14) A conductive film consisting of a Y film (thickness: 10 nm) as the conductive film underlayer and a TaN film (thickness: 60 nm) as the conductive film upper layer was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a Y target and argon (Ar) as the sputtering gas were used to deposit the Y film. The TaN film was deposited in the same manner as the TaN film as the conductive film underlayer in Example 10.

[0213] Next, a multilayer reflective film was deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1. Furthermore, in the same manner as in Example 7, a protective film made of RuRhCrN (film thickness: 2.5 nm) was deposited on the Si film furthest from the substrate surface of the multilayer reflective film to obtain a substrate with a multilayer reflective film.

[0214] Next, in the same manner as in Example 1, an absorber film consisting of a laminated film of a TaBO film (film thickness: 4 nm) as the lower absorber layer and a PtTa film (film thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate using a DC magnetron sputtering apparatus. A reflective mask blank was obtained in this manner.

[0215] Next, in the same manner as in Example 1, an absorber film pattern was formed by etching the absorber film of the reflective mask blank. Furthermore, in order to form a light-shielding region, the protective film was etched in the same manner as in Example 13. Then, under conditions of a pressure Pch of 4 mTorr and a temperature Tch of 60°C in the etching chamber, a light-shielding region was formed by etching the multilayer reflective film as the first film with a fluorine-based gas. The fluorine-based gas was CF containing fluorine as a halogen. ４ It is a mixed gas of gas and He gas, CF ４ The flow rate ratio (%) of He is CF ４ The ratio of He to He was 60:40. Furthermore, the resist pattern on the absorber film pattern was removed to obtain a reflective mask.

[0216] The conductive film of this embodiment includes a layer made of Y, and YF ３ The normal boiling point T １The temperature was 2503 (K), and the standard boiling point Tb was 1615 (K). Therefore, in this embodiment, the YF from the conductive film (lower layer) at a temperature of 60°C during etching of the multilayer reflective film was ３ The vapor pressure Pm is 1.10 × 10 as stated above. ―２２ It was mTorr. As mentioned above, following the procedure for deriving the vapor pressure curve, YF ３ The vapor pressure curve was derived, and from the obtained vapor pressure curve, YF at a temperature of 60°C ３ The vapor pressure Pm was calculated. Therefore, in this embodiment, in etching the multilayer reflective film as the first film, the YF from the conductive film at etching temperature Tch 60°C ３ The vapor pressure Pm was lower than the etching pressure Pch 4mTorr. The etching rate of the multilayer reflective film was 0.2 nm / second. After etching of the absorber film, protective film, and multilayer reflective film, the outer periphery of the second main surface (back surface) of the substrate was not exposed. In other words, even when difficult-to-etch materials were used for the absorber film, protective film, and multilayer reflective film, the exposure of the second main surface (back surface) of the substrate at the outer periphery due to etching of the absorber film, protective film, and multilayer reflective film, etc., could be suppressed during the manufacturing process of the reflective mask.

[0217] The reflective mask obtained in this embodiment was set in the exposure apparatus, and a pattern transfer was performed onto the semiconductor substrate on which the resist film had been formed. As a result, the reflective mask was well supported by the electrostatic chuck via the conductive film, and high-precision pattern transfer was possible without any shift in the transfer position during exposure.

[0218] (Comparative Example 1) A conductive film made of TaN was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a Ta target and a mixed gas of argon and nitrogen as the sputtering gas (flow rate ratio (%) Ar:N) were placed inside. ２ A TaN film with a thickness of 70 nm was formed using a mixture of 65:35. The composition ratio of the TaN film was Ta:N = 74 atomic%:26 atomic%.

[0219] Next, a multilayer reflective film and a protective film were sequentially deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0220] Next, in the same manner as in Example 1, an absorber film consisting of a laminated film of a TaBO film (film thickness: 4 nm) as the lower absorber layer and a PtTa film (film thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate using a DC magnetron sputtering apparatus. A reflective mask blank was obtained in this manner.

[0221] Next, a reflective mask was fabricated using the above-mentioned reflective mask blank in the same manner as in Example 1.

[0222] The conductive film in this comparative example contains Ta, and TaCl ５ The normal boiling point T １ The temperature was 512 (K), and the standard boiling point Tb was 506 (K). Therefore, in this comparative example, the TaCl derived from the conductive film at the etching temperature of the PtTa film, which is the first film and is the upper layer of the absorber film, at 60°C. ５ The vapor pressure Pm is 1.89 × 10⁻⁶ ３ It was mTorr. As mentioned above, following the procedure for deriving the vapor pressure curve, TaCl ５ The vapor pressure curve was derived, and the vapor pressure Pm of the Ta halogen compound at a temperature of 60°C was calculated from the obtained vapor pressure curve. Therefore, in this comparative example, during etching of the PtTa film as the first film, which is the upper layer of the absorber, the TaCl derived from the conductive film at the etching temperature of 60°C ５The vapor pressure Pm was higher than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the PtTa film as the absorber upper layer under the above etching conditions was 0.07 nm / second. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching the PtTa film as the absorber upper layer under the above etching conditions was 80% of the film thickness at the outer periphery of the conductive film before etching the PtTa film. In addition, the surface of the back surface was exposed in a part of the outer periphery of the back surface of the substrate. In other words, in this comparative example, when a difficult-to-etch material was used for the absorber film, the conductive film suffered significant damage due to etching of the absorber film during the manufacturing process of the reflective mask.

[0223] The reflective mask obtained in this comparative example was set in the exposure apparatus, and a pattern transfer was performed onto a semiconductor substrate on which a resist film had been formed. As a result, due to insufficient adsorption force by the electrostatic chuck, a shift in the transfer position occurred during exposure, making it impossible to perform high-precision pattern transfer.

[0224] (Comparative Example 2) A conductive film made of CrN was formed on the back surface of a substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and a Cr target and a mixed gas of argon and nitrogen as the sputtering gas (flow rate ratio (%) Ar:N) were placed inside. ２ A CrN film with a thickness of 70 nm was formed using a mixture of Cr:N (90:10). The composition ratio of the CrN film was Cr:N = 90 atomic%:10 atomic%.

[0225] Next, a multilayer reflective film and a protective film were sequentially deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0226] Next, in the same manner as in Example 6, an absorber film consisting of a laminated film of a TaBO film (film thickness: 4 nm) as the lower absorber layer and a RuCrON film (film thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate using a DC magnetron sputtering apparatus. A reflective mask blank was obtained in this manner.

[0227] Next, a reflective mask was fabricated using the above-mentioned reflective mask blank in the same manner as in Example 1.

[0228] The Cr contained in the conductive film of this comparative example is the etchant gas of the upper layer of the absorber film as the first film, Cl ２ and O ２ It reacts with volatile CrO ２ Cl ２ Therefore, in this comparative example, CrO ２ Cl ２ The vapor pressure of CrO was determined. ２ Cl ２ The normal boiling point T １ The temperature was 390 (K), and the standard boiling point Tb was 390 (K). Therefore, in this comparative example, the CrO from the conductive film at the etching temperature of the RuCrON film, which is the first film and is the upper layer of the absorber film, at 60°C. ２ Cl ２ The vapor pressure Pm is 1.44 × 10⁻⁶ ５ It was mTorr. As mentioned above, following the procedure for deriving the vapor pressure curve, CrO ２ Cl ２ The vapor pressure curve was derived, and from the obtained vapor pressure curve, the CrO2 at a temperature of 60°C was used. ２ Cl ２ The vapor pressure Pm was calculated. Therefore, in this comparative example, in etching the RuCrON film as the first film, which is the upper layer of the absorber, the CrO contained in the conductive film at etching temperature Tch 60°C was calculated. ２ Cl ２The vapor pressure Pm was higher than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the RuCrON film as the absorber upper layer under the above etching conditions was 0.04 nm / second. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching the RuCrON film as the absorber upper layer under the above etching conditions was 80% of the film thickness at the outer periphery of the conductive film before etching the RuCrON film. In addition, the surface of the back surface was exposed in a part of the outer periphery of the back surface of the substrate. In other words, in this comparative example, when a difficult-to-etch material was used for the absorber film, the damage to the conductive film due to etching of the absorber film during the manufacturing process of the reflective mask was significant.

[0229] The reflective mask obtained in this comparative example was set in the exposure apparatus, and a pattern transfer was performed onto the semiconductor substrate on which the resist film had been formed. As a result, due to insufficient adsorption force by the electrostatic chuck, a shift in the transfer position occurred during exposure, making it impossible to perform high-precision pattern transfer.

[0230] (Comparative Example 3) A conductive film made of TaN was formed on the back surface of a substrate prepared in the same manner as in Example 1, in the same manner as in Comparative Example 1.

[0231] Next, a multilayer reflective film was deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1. Furthermore, in the same manner as in Example 7, a protective film made of RuRhCrN (film thickness: 2.5 nm) was deposited on the Si film furthest from the substrate surface of the multilayer reflective film. A substrate with a multilayer reflective film was obtained in this manner.

[0232] Next, in the same manner as in Example 7, an absorber film consisting of a laminated film of a CrN film (film thickness: 4 nm) as the lower absorber layer and a PtRu film (film thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate using a DC magnetron sputtering apparatus. A reflective mask blank was obtained in this manner.

[0233] Next, a reflective mask was fabricated using the above-mentioned reflective mask blank in the same manner as in Example 7.

[0234] The conductive film in this comparative example contains Ta, and TaF５ The normal boiling point T １ The temperature was 503 (K), and the standard boiling point Tb was 507 (K). Therefore, in this comparative example, the TaF from the conductive film at a temperature of 60°C during etching of the absorber film was ５ The vapor pressure Pm is 1.96 × 10⁻⁶ ３ It was mTorr. As mentioned above, following the procedure for deriving the vapor pressure curve, TaF ５ The vapor pressure curve was derived, and from the obtained vapor pressure curve, TaF at a temperature of 60°C was used. ５ The vapor pressure Pm was calculated. Therefore, in this comparative example, in etching the PtRu film as the first film, which is the upper layer of the absorber, the TaF contained in the conductive film at an etching temperature of 60°C was calculated. ５ The vapor pressure Pm was higher than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the PtRu film as the absorber upper layer under the above etching conditions was 0.09 nm / second. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching the PtRu film as the absorber upper layer under the above etching conditions was 80% of the film thickness at the outer periphery of the conductive film before etching the PtRu film. In addition, the surface of the back surface was exposed in a part of the outer periphery of the back surface of the substrate. In other words, in this comparative example, when a difficult-to-etch material was used for the absorber film, the damage to the conductive film due to etching of the absorber film during the manufacturing process of the reflective mask was significant.

[0235] The reflective mask obtained in this comparative example was set in the exposure apparatus, and a pattern transfer was performed onto the semiconductor substrate on which the resist film had been formed. As a result, due to insufficient adsorption force by the electrostatic chuck, a shift in the transfer position occurred during exposure, making it impossible to perform high-precision pattern transfer.

[0236] (Comparative Example 4) A conductive film made of TaN was formed on the back surface of a substrate prepared in the same manner as in Example 1, in the same manner as in Comparative Example 1.

[0237] Next, a multilayer reflective film was deposited on the substrate surface opposite to the conductive film, in the same manner as in Example 1. Furthermore, in the same manner as in Example 7, a protective film made of RuRhCrN (film thickness: 2.5 nm) was deposited on the Si film furthest from the substrate surface of the multilayer reflective film. A substrate with a multilayer reflective film was obtained in this manner.

[0238] Next, in the same manner as in Example 9, an absorber film consisting of a laminated film of a CrN film (film thickness: 4 nm) as the lower absorber layer and an IrTaO film (film thickness: 30 nm) as the upper absorber layer was formed on the protective film of the multilayer reflective film substrate using a DC magnetron sputtering apparatus. A reflective mask blank was obtained in this manner.

[0239] Next, a reflective mask was fabricated using the above-mentioned reflective mask blank in the same manner as in Example 9.

[0240] The conductive film in this comparative example contains Ta, similar to Comparative Example 3. Therefore, similar to Comparative Example 3, the TaF at a temperature of 60°C is... ５ The vapor pressure Pm was calculated. In this comparative example, during etching of the IrTaO film, which is the first film and is the upper layer of the absorber, the TaF derived from the conductive film at an etching temperature of 60°C was calculated. ５ The vapor pressure Pm is 1.96 × 10⁻⁶. ３ The mTorr was higher than the etching pressure Pch 4mTorr. Furthermore, the etching rate of the IrTaO film as the absorber upper layer under the above etching conditions was 0.15 nm / second. Also, the amount of film thickness reduction at the outer periphery of the conductive film after etching the IrTaO film as the absorber upper layer under the above etching conditions was 70% of the film thickness at the outer periphery of the conductive film before etching the IrTaO film. In addition, the surface of the back surface was exposed in a part of the outer periphery of the back surface of the substrate. In other words, in this comparative example, when a difficult-to-etch material was used for the absorber film, the damage to the conductive film due to etching of the absorber film during the manufacturing process of the reflective mask was significant.

[0241] The reflective mask obtained in this comparative example was set in the exposure apparatus, and a pattern transfer was performed onto the semiconductor substrate on which the resist film had been formed. As a result, due to insufficient adsorption force by the electrostatic chuck, a shift in the transfer position occurred during exposure, making it impossible to perform high-precision pattern transfer.

[0242] 1. Substrate 2. Conductive film 3. Multilayer reflective film 4. Protective film 5. Absorber film 6. Etching mask film 7. First film 10. Mask blank 20. Substrate with multilayer reflective film 30, 40, 50. Reflective mask blank 60. Reflective mask 70. Mask blank

Claims

1. A mask blank comprising: a substrate having a first main surface and a second main surface opposite to the first main surface; a first film formed on the first main surface; and a conductive film formed on the second main surface, wherein the conductive film contains a metal M1, and when pressure Pch and temperature Tch are used to etch the first film with a halogen, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower at temperature Tch than at pressure Pch.

2. The mask blank according to claim 1, characterized in that the halogen is fluorine or chlorine.

3. The mask blank according to claim 1 or 2, characterized in that the metal M1 is at least one selected from palladium, iridium, rhodium, zirconium, and yttrium.

4. The mask blank according to claim 1 or 2, characterized in that the conductive film contains tantalum or chromium in addition to the metal M1.

5. The mask blank according to claim 1 or 2, characterized in that the conductive film is formed by a single layer film containing 3 atomic percent or more of the metal M1.

6. The mask blank according to claim 1 or 2, characterized in that the conductive film is formed by two or more layers, each including a layer L1 containing 3 atomic percent or more of the metal M1.

7. Primary ion species is Cs ＋ When the conductive film was analyzed in an arbitrary 124 μm square region within a 5 cm square including the center of the substrate by dynamic secondary ion mass spectrometry under the conditions of a primary acceleration voltage of 3.0 kV and a primary ion current of 25 nA, the conductive film was found to be 1.0 × 10⁻¹⁶. ２ A mask blank according to claim 1 or 2, characterized by having a secondary ion strength of hydrogen of cps or higher.

8. The mask blank according to claim 1 or 2, characterized in that the conductive film is formed in contact with the second main surface.

9. The mask blank according to claim 1 or 2, characterized in that the conductive film consists of a single layer or a single layer including a surface oxidation region on the outermost surface.

10. The mask blank according to claim 1 or 2, characterized in that the conductive film comprises a layer L1 containing the metal M1 and a layer L2 containing a metal M2 different from the metal M1.

11. The mask blank according to claim 10, characterized in that the metal M2 is tantalum or chromium.

12. The mask blank according to claim 10, characterized in that the layer L1 is formed on the layer L2.

13. The mask blank according to claim 10, characterized in that the layer L2 is formed on the layer L1.

14. The mask blank according to claim 1 or 2, characterized in that the first film contains at least one of ruthenium, platinum, iridium, rhodium, and silicon.

15. The mask blank according to claim 1 or 2, characterized in that, at the temperature Tch and pressure Pch, the etching rate of the first film when the first film is etched with the halogen is 0.5 nm / second or less.

16. A mask comprising: a substrate having a first main surface and a second main surface opposite to the first main surface; a first film formed on the first main surface; and a conductive film formed on the second main surface, wherein the conductive film contains a metal M1, and when pressure Pch and temperature Tch are used to etch the first film with a halogen, the vapor pressure Pm of the halogen compound consisting of the halogen and the metal M1 is lower than the pressure Pch at temperature Tch.

17. The mask according to claim 16, characterized in that the halogen is fluorine or chlorine.

18. The mask according to claim 16 or 17, characterized in that the metal M1 is at least one selected from palladium, iridium, rhodium, zirconium, and yttrium.

19. The mask according to claim 16 or 17, characterized in that the conductive film includes tantalum or chromium in addition to the metal M1.

20. The mask according to claim 16 or 17, characterized in that the conductive film is formed by a single layer film containing 3 atomic percent or more of the metal M1.

21. The mask according to claim 16 or 17, characterized in that the conductive film is formed of two or more layers, each including a layer L1 containing 3 atomic percent or more of the metal M1.

22. Primary ion species is Cs ＋ When the conductive film was analyzed in an arbitrary 124 μm square region within a 5 cm square including the center of the substrate by dynamic secondary ion mass spectrometry under the conditions of a primary acceleration voltage of 3.0 kV and a primary ion current of 25 nA, the conductive film was found to be 1.0 × 10⁻¹⁶. ２ The mask according to claim 16 or 17, characterized in that it has a secondary ion strength of hydrogen of cps or higher.

23. The mask according to claim 16 or 17, characterized in that the conductive film is formed in contact with the second main surface.

24. The mask according to claim 16 or 17, characterized in that the conductive film consists of a single layer or a single layer including a surface oxidation region on the outermost surface.

25. The mask according to claim 16 or 17, characterized in that the conductive film comprises a layer L1 containing the metal M1 and a layer L2 containing a metal M2 different from the metal M1.

26. The mask according to claim 25, characterized in that the metal M2 is tantalum or chromium.

27. The mask according to claim 25, characterized in that the layer L1 is formed on the layer L2.

28. The mask according to claim 25, characterized in that the layer L2 is formed on the layer L1.

29. The mask according to claim 16 or 17, characterized in that the first film comprises at least one of ruthenium, platinum, iridium, rhodium, and silicon.

30. The mask according to claim 16 or 17, characterized in that, at the temperature Tch and pressure Pch, the etching rate of the first film when the first film is etched with the halogen is 0.5 nm / second or less.

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