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

Abstract

To provide a conductive film-equipped substrate capable of inhibiting deformation of a mask substrate caused by stress change in a conductive film even when a reflective mask manufactured by applying the conductive film-equipped substrate is exposed to an exposure environment.SOLUTION: A conductive film-equipped substrate has a substrate and a conductive film that is formed on a first main surface of the substrate and contains hydrogen, where the conductive film is a single layer film or a lamination film including a lower layer and an upper layer formed on the lower layer; the single layer film and the lower layer contain a metal and nitrogen or boron, and the upper layer contains a metal and oxygen; and when the conductive film is analyzed by dynamic secondary ion mass spectrometry under conditions in which a primary ion species is Cs+; a primary acceleration voltage is 3.0 kV; and a primary ion current is 25 nA, in an arbitrarily defined 124 μm square region within a 5 cm square including the center of the substrate, a secondary ion intensity of detected hydrogen is 1.0×102 cps or more.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Generally, in the manufacturing process of semiconductor devices, fine patterns are formed using photolithography. Also, for the formation of these fine patterns, usually several transfer masks called photomasks are used. This transfer mask generally has a fine pattern made of a metal thin film or the like provided on a glass substrate, and in the manufacture of this transfer mask, an electron beam lithography method is used.

[0003] For the manufacture of a transfer mask by an electron beam lithography method, a mask blank having a thin film (such as 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 includes a drawing step of performing desired pattern drawing on a resist film formed on the mask blank, a developing step of developing the resist film after drawing to form a desired resist pattern, an etching step of etching the thin film using this resist pattern as a mask, and a step of peeling and removing the remaining resist pattern. In the above developing step, after performing desired pattern drawing on the resist film formed on the mask blank, a developer is supplied to dissolve the portion of the resist film that is soluble in the developer and form a resist pattern. Also, in the above etching step, using this resist pattern as a mask, the portion where the thin film where the resist pattern is not formed is exposed is removed by dry etching or wet etching, thereby forming a desired mask pattern on the substrate. Thus, the transfer mask is completed.

[0004] As types of transfer masks, in addition to a binary mask having a light-shielding film pattern made of a chromium-based material on a conventional substrate, a phase shift mask is known.

[0005] In recent years, in the semiconductor industry, with the high integration of semiconductor devices, there has been a need for fine patterns that exceed the transfer limit of the conventional lithography method using ultraviolet light. To enable the formation of such fine patterns, there is EUV lithography, which is an exposure technique using extreme ultraviolet (hereinafter referred to as "EUV") light. Here, EUV light refers to light in the wavelength band of the soft X-ray region or the vacuum ultraviolet region, and is light with a wavelength of about 0.2 to 100 nm. In this specification, EUV light is light including light with a wavelength of 13.5 nm, and can be light with a wavelength from 13 nm to 14 nm, more specifically, light with a wavelength of 13.5 nm. In this specification, light includes not only visible light but also electromagnetic waves. As a mask used in this EUV lithography, there is a reflective mask. Such a reflective mask has a multilayer reflective film formed on a substrate that reflects EUV light, which is exposure light, and an absorber film that absorbs EUV light is formed in a pattern on the multilayer reflective film.

[0006] The reflective mask is supported by an electrostatic chuck in an exposure apparatus, for example, when transferring a pattern onto a semiconductor substrate. On the other hand, the reflective mask blank and the substrate used for the reflective mask are 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 reflective mask blank or the substrate of the 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. Further, Patent Document 2 discloses a reflective mask blank for EUV lithography in which a conductive film made of a material containing tantalum and substantially not containing hydrogen is formed.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

[0008] In a reflective mask blank, as time passes after manufacturing, due to the change over time of the film stress of the conductive film, the substrate flatness changes, and a new problem has occurred that it is difficult to guarantee the pattern position accuracy in an EUV mask.

[0009] In the above Patent Document 2, it is presumed that the reason why the compressive stress of the conductive film immediately after film formation on the glass substrate increases with the passage of time is that hydrogen contained in the glass substrate is gradually taken into the conductive film over time. Under this presumption, Patent Document 2 discloses providing a hydrogen intrusion prevention film between the glass substrate and the conductive film for the purpose of suppressing fluctuations in substrate flatness due to the intrusion of hydrogen contained in the glass substrate into the conductive film.

[0010] However, even if the intrusion of hydrogen contained in the glass substrate into the conductive film is suppressed, it is conceivable that hydrogen in the exposure environment of the EUV mask will intrude into the conductive film during exposure. In recent years, exposure apparatuses with a larger numerical aperture (NA) of the projection optical system have been studied in order to improve the resolution performance. Along with the transition to such an exposure apparatus, the exposure output increases, and the intrusion of the generated hydrogen plasma into the conductive film is accelerated, deforming the mask substrate, and there is concern about the shift in the transfer position during exposure.

[0011] Therefore, the present invention has been made in view of such problems, and its object is, firstly, to provide a substrate with a conductive film that can suppress deformation of the mask substrate due to stress changes in the conductive film on the back surface even when a reflective mask manufactured from a reflective mask blank using a substrate with a conductive film is exposed to an exposure environment. Second, a substrate with a multilayer reflective film, a reflective mask blank, and a reflective mask using the substrate with the conductive film are provided. Third, a method for manufacturing a semiconductor device using the reflective mask is provided.

Means for Solving the Problems

[0012] As a result of continuous intensive research to solve the conventional problems, the present inventor has completed the following invention. (Configuration 1) A substrate with a conductive film, comprising a substrate and a conductive film formed on the first main surface of the substrate and containing hydrogen. The conductive film is a single-layer film or a laminated film including a lower layer and an upper layer formed on the lower layer. The single-layer film and the lower layer contain a metal and nitrogen or boron, the upper layer contains a metal and oxygen, and the primary ion species is Cs + , when the conductive film is 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 that the primary acceleration voltage is 3.0 kV and the primary ion current is 25 nA, the secondary ion intensity of hydrogen detected is 1.0×10 2 cps or more. A substrate with a conductive film characterized by this.

[0013] (Configuration 2) The substrate with a conductive film according to Configuration 1, wherein the single-layer film and the lower layer are formed in contact with the substrate. (Configuration 3) The substrate with a conductive film according to Configuration 1 or 2, wherein the secondary ion intensity of hydrogen is 1.0×10 2 cps or more within a range of 5 nm in the film thickness direction from the outermost surface of the conductive film farthest from the substrate.

[0014] (Configuration 4) The substrate with a conductive film according to Configuration 1 or 2, having a bottommost layer containing a metal and oxygen between the substrate and the lower layer. (Configuration 5) The conductive film - attached substrate according to Configuration 1 or 2, wherein the conductive film contains tantalum or chromium.

[0015] (Configuration 6) The conductive film - attached substrate according to Configuration 1 or 2, wherein the single - layer film and the lower layer contain nitrogen in an amount of 10 atomic% or more and 40 atomic% or less.

[0016] (Configuration 7) A substrate with a multilayer reflective film, having a multilayer reflective film formed on a second main surface facing the first main surface of the conductive film - attached substrate according to Configuration 1 or 2.

[0017] (Configuration 8) A reflective mask blank, having an absorber film formed on the multilayer reflective film of the substrate with a multilayer reflective film according to Configuration 7. (Configuration 9) A reflective mask, having an absorber film pattern obtained by patterning the absorber film of the reflective mask blank according to Configuration 8.

[0018] (Configuration 10) A method for manufacturing a semiconductor device, including a step of transferring the absorber film pattern to a transfer target by exposure using the reflective mask according to Configuration 9. [Advantages of the Invention]

[0019] According to the present invention, it is possible to provide a conductive film - attached substrate that can suppress deformation of the mask substrate due to stress change of the conductive film on the back surface even when a reflective mask manufactured from a reflective mask blank using the conductive film - attached substrate is exposed to an exposure environment. Also, according to the present invention, it is possible to provide a substrate with a multilayer reflective film, a reflective mask blank, and a reflective mask using the above - mentioned conductive film - attached substrate. Even when a reflective mask manufactured from a reflective mask blank using the above - mentioned conductive film - attached substrate is exposed to an exposure environment, deformation of the mask substrate due to stress change of the conductive film on the back surface can be suppressed.

[0020] Furthermore, according to the present invention, a method for manufacturing a semiconductor device using this reflective mask can be provided. By performing pattern transfer using this reflective mask, even when the reflective mask is exposed to the exposure environment during pattern transfer, deformation of the mask substrate due to stress change in the conductive film on the back surface can be suppressed, so that high-precision pattern transfer can be performed without causing displacement of the transfer position during exposure.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described in detail. [Substrate with Conductive Film] First, the substrate with a conductive film of the present invention will be described. The substrate with a conductive film of the present invention has a substrate and a conductive film formed on the first main surface of the substrate and containing hydrogen. The conductive film is a single-layer film or a laminated film including a lower layer and an upper layer formed on the lower layer. The single-layer film and the lower layer contain a metal and nitrogen or boron, the upper layer contains a metal and oxygen, and the primary ion species is Cs +, when analyzing the conductive film 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 secondary ion intensity of hydrogen detected is 1.0×10 2 cps or more. Here, the center of the substrate means the intersection of the diagonals of the first main surface.

[0023] FIG. 1 is a cross-sectional view showing an embodiment of the substrate with a conductive film of the present invention. As shown in FIG. 1, in the substrate 10 with a conductive film of the present embodiment, a conductive film 2 is provided on the first main surface of the substrate 1 (the back surface of the substrate 1 in the illustrated state). In the present embodiment, the conductive film 2 is formed in contact with the substrate 1.

[0024] <Substrate> The substrate 1 has two main surfaces facing each other and four end faces. When the substrate with a conductive film of the present invention is used, for example, as a reflective mask blank for EUV exposure, a glass substrate is preferably used as the substrate 1. In particular, in order to prevent pattern distortion due to heat during exposure, it is 0 ± 1.0×10 -7 / °C, more preferably 0 ± 0.3×10 -7 Substrates having a low coefficient of thermal expansion within the range of / °C are preferably used. As materials having a low coefficient of thermal expansion within this range, for example, SiO2-TiO2-based glass, multi-component glass ceramics, etc. can be used.

[0025] The main surface (the second main surface) on which the transfer pattern of the glass substrate is formed is surface-treated to have a high flatness from at least the viewpoints of improving pattern transfer accuracy and position accuracy. In the case of EUV exposure, in the region of 142 mm × 142 mm of the main surface on which the transfer pattern of the glass substrate is formed, the flatness is preferably 0.1 μm or less, and particularly preferably 0.05 μm or less. In this specification, the flatness is a value representing the warpage (deformation amount) of the 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, with the plane determined by the least squares method with the surface of the substrate 1 as the reference being the focal plane.

[0026] Also, in the case of EUV exposure, as the glass substrate, as described above, a material having a low coefficient of thermal expansion such as SiO2-TiO2-based glass is preferably used. For the purpose of reducing the surface roughness of the glass substrate or reducing defects on the surface of the glass substrate, a base layer may be formed on the main surface on the side where the transfer pattern of the glass substrate is formed, if necessary. As the material for such a base layer, it is not necessary to have translucency to the exposure light, and a material that can obtain high smoothness when the surface of the base layer is precision-polished and has good defect quality is preferably selected. For example, Si or a silicon compound containing Si (such as SiO2, SiON, etc.) is preferably used as the material for the base layer because high smoothness can be obtained when precision-polished and the defect quality is good. The material of the base layer is particularly preferably Si. By using such a base layer, high smoothness with a root mean square roughness (Rq) of 0.1 nm or less, for example, can be realized as the surface roughness of the glass substrate.

[0027] The surface of the underlying layer is preferably a surface that has been precisely polished to achieve the smoothness required for a substrate for a reflective mask blank. The surface of the underlying layer is desirably precisely polished so that the root mean square roughness (Rq) is 0.15 nm or less, particularly preferably 0.1 nm or less. Further, considering the influence on the surface of the multilayer reflective film formed on the underlying layer, in relation to the maximum height (Rmax), it is good if Rmax / Rq is 2 to 10, and particularly preferably, it is desirably precisely polished so that it is 2 to 8. The film thickness of the underlying layer is preferably in the range of, for example, 10 nm to 300 nm.

[0028] <Conductive film> In the present invention, the conductive film 2 is a single-layer film or a laminated film including a lower layer and an upper layer formed on the lower layer. First, the case where the conductive film 2 is a single-layer film will be described. When the conductive film 2 is a single-layer film, the film formation process becomes simple. Also, in this case, the single-layer film is formed in contact with the substrate 1.

[0029] In the present invention, the single-layer film is made of a material containing a metal and nitrogen or boron. The single-layer film preferably contains at least one selected from, for example, Ta, Cr, Pt, Au, Rh, Ru, Ir, and Hf as the metal. The single-layer film particularly preferably contains tantalum or chromium. That is, as the material of the single-layer film, for example, tantalum-based materials and chromium-based materials are preferably mentioned. Examples of tantalum-based materials include materials containing nitrogen or boron in tantalum, and in addition, it may contain one or more selected from, for example, carbon, oxygen, hydrogen, noble gases, etc. Examples of chromium-based materials include materials containing nitrogen or boron in chromium, and in addition, it may contain one or more selected from, for example, carbon, oxygen, hydrogen, noble gases, etc. When the single-layer film contains a noble gas, the content of the noble gas is preferably 5 atomic% or less, more preferably 3 atomic% or less, and still more preferably 1.5 atomic% or less. The same applies to the lower layer, upper layer, and bottom layer described below.

[0030] In particular, since the above tantalum-based material has high cleaning resistance, in the present invention, the single-layer film is preferably made of a tantalum-based material. Further, from the viewpoints of chemical resistance and abrasion resistance, it is more preferable that the metal contained in the single-layer film is only tantalum.

[0031] When the single-layer film is made of a tantalum-based material, specific examples include, for example, TaN, TaB, TaBN, etc. When the single-layer film contains tantalum, the content of tantalum is preferably 50 atomic% or more, more preferably 60 atomic% or more. Further, the content of tantalum in the single-layer film can be 100 atomic% or less except for the substrate interface region and the surface layer region described below.

[0032] When the single-layer film contains nitrogen, the nitrogen content is preferably 1 atomic% or more, more preferably 10 atomic% or more, and still more preferably 15 atomic% or more. Further, it is preferably 40 atomic% or less, more preferably 30 atomic% or less, and still more preferably 25 atomic% or less.

[0033] When the single-layer film contains boron, the boron content is preferably 1 atomic% or more, more preferably 5 atomic% or more. Further, it is preferably 30 atomic% or less, more preferably 20 atomic% or less, and still more preferably 18 atomic% or less.

[0034] When the single-layer film contains oxygen, the oxygen content is preferably 20 atomic% or more, more preferably 18 atomic% or more. Further, the single-layer film may not contain oxygen except for the composition gradient region described below.

[0035] Note that the surface of the single-layer film that is farthest from the first main surface of the substrate 1 may be oxidized. That is, the conductive film 2 may have a surface oxide layer with a very small film thickness on the surface that is farthest from the first main surface of the substrate 1. The film thickness of the surface oxide layer can be 4 nm or less, preferably 2 nm or less, and more preferably 1 nm or less. Also, both the interface region (substrate interface region) between the single-layer film and the substrate 1 and the surface layer region of the single-layer film that is away from the first main surface of the substrate 1 are composition gradient regions where the composition ratio of the single-layer film changes continuously. Therefore, when the above-mentioned conductive film 2 is composed of a single-layer film, it includes the case where the conductive film 2 is composed of a composition gradient region (surface layer region and substrate interface region) and an internal region other than the composition gradient region (a region where the composition ratio is uniform in the film thickness direction). Here, the composition ratio being uniform in the film thickness direction means that the difference between each constituent element in the film thickness direction is so small that it can be ignored. For example, it means that the difference between each constituent element is all 3 atomic% or less. The above-mentioned substrate interface region is a region that extends, for example, from the interface between the single-layer film and the substrate 1 to a thickness of more than 0 nm and 5 nm or less toward the surface (the outermost surface) of the single-layer film that is farthest from the first main surface of the substrate 1. The thickness of the substrate interface region is more preferably 4 nm or less, and even more preferably 3 nm or less. Also, the above-mentioned surface layer region is a region that extends, for example, from the outermost surface of the single-layer film to a thickness of more than 0 nm and 5 nm or less toward the first main surface of the substrate 1. The thickness of the surface layer region is more preferably 4 nm or less, and even more preferably 3 nm or less.

[0036] Next, the case where the conductive film 2 is a laminated film including a lower layer and an upper layer formed on the lower layer will be described. In this case, the lower layer of the laminated film can be formed in contact with the substrate 1. The lower layer may include a composition gradient region where the composition changes in the film thickness direction in the vicinity of the interface with another layer in contact with the lower layer or the substrate 1. The film thickness of this composition gradient region can be, for example, more than 0 nm and 5 nm or less. The same applies to the upper layer and the bottommost layer described later.

[0037] The lower layer of the above-mentioned laminated film is made of a material containing a metal and nitrogen or boron. That is, it can be the same as the material of the single-layer film when the above-mentioned conductive film 2 is a single-layer film. Therefore, a detailed description of the material of the lower layer is omitted.

[0038] In addition, the upper layer of the above-mentioned laminated film is made of a material containing a metal and oxygen. The above-mentioned upper layer preferably contains at least one selected from, for example, Ta, Cr, Pt, Au, Rh, Ru, Ir, and Hf as the above-mentioned metal. The above-mentioned upper layer particularly preferably contains tantalum or chromium. That is, as the material of the above-mentioned upper layer, for example, tantalum-based materials and chromium-based materials are preferably mentioned. Examples of the tantalum-based material include a material containing tantalum and oxygen, and in addition, it may contain one or more selected from, for example, carbon, nitrogen, boron, hydrogen, noble gases, etc. Examples of the chromium-based material include a material containing chromium and oxygen, and in addition, it may contain one or more selected from, for example, carbon, nitrogen, boron, hydrogen, noble gases, etc.

[0039] Particularly, since the above-mentioned tantalum-based material has high cleaning resistance, in the present invention, it is preferable that not only the lower layer but also the upper layer of the above-mentioned laminated film is made of a tantalum-based material. Further, from the viewpoints of chemical resistance and abrasion resistance, it is more preferable that the metal contained in the above-mentioned upper layer is only tantalum.

[0040] When the above-mentioned upper layer is made of a tantalum-based material, specific examples include, for example, TaO, TaBO, TaNO, TaBNO, etc. When the above-mentioned upper layer contains tantalum, the content of tantalum is preferably 10 atomic% or more, and more preferably 20 atomic% or more. Further, the content of tantalum in the upper layer is preferably 70 atomic% or less, and more preferably 60 atomic% or less.

[0041] In addition, the oxygen content in the upper layer preferably is 20 atomic % or more, more preferably 30 atomic % or more. Also, the oxygen content in the upper layer preferably is 80 atomic % or less, more preferably 70 atomic % or less.

[0042] When the upper layer contains boron, the boron content preferably is 0.5 atomic % or more. Also, the boron content preferably is 25 atomic % or less. When the upper layer contains nitrogen, the nitrogen content preferably is 0.5 atomic % or more and preferably 40 atomic % or less.

[0043] In the upper layer, the composition may vary in the film thickness direction. In this case, the average value of the content of each constituent atom in the film thickness direction of the upper layer may be defined as the content of each constituent atom in the entire upper layer. The same applies to the lowermost layer described later.

[0044] Also, between the substrate 1 and the lower layer, a lowermost layer made of a material containing metal and oxygen can be provided. That is, the conductive film 2 can be a three-layer laminated film of the lowermost layer, the lower layer, and the upper layer. In this case, the material of the lowermost layer is preferably the same as the material of the upper layer described above. Note that the lowermost layer and the upper layer may be the same material or different materials, and when they are the same material, the composition ratio of the constituent components may be different. Also, when the conductive film 2 is a laminated film, it is not limited to the two-layer laminated film or the three-layer laminated film described above, and may be, for example, a laminated film of four or more layers.

[0045] The film thickness of the conductive film 2 is not particularly limited, but in any case where the conductive film 2 is a single-layer film or a laminated film, for example, 10 nm or more is preferable, and 20 nm or more is more preferable. Also, the film thickness is preferably 500 nm or less, more preferably 200 nm or less, and even more preferably 100 nm or less. Also, when the conductive film 2 is a laminated film, the film thickness ratio of each layer is not particularly limited. The method for forming the conductive film 2 is not particularly limited, but usually, a magnetron sputtering method, an ion beam sputtering method, or the like is suitable.

[0046] In the present invention, the conductive film 2 is preferably amorphous. This can make the surface of the conductive film 2 smooth and flat.

[0047] In the present invention, the conductive film 2 preferably has compressive stress. By having compressive stress, the warping of the substrate 1 caused by the multilayer reflective film can be improved in reducing.

[0048] As described above, in the substrate with a conductive film of the present invention, when the conductive film is analyzed by dynamic secondary ion mass spectrometry under the conditions that the primary ion species is Cs + , the primary acceleration voltage is 3.0 kV, and the primary ion current is 25 nA, in any 124 μm square region within a 5 cm square including the center of the substrate, when the secondary ion intensity of hydrogen detected is 1.0×10 2 cps or more.

[0049] In the present invention, the conductive film 2 further contains hydrogen. By previously containing hydrogen in the conductive film 2 in the range where the secondary ion intensity of hydrogen detected when analyzing the conductive film 2 by the above analysis method is 1.0×10 2 cps or more, it is possible to suppress hydrogen generated in the exposure environment from entering the conductive film during the exposure of the reflective mask.

[0050] When the reflective mask is exposed to the exposure environment, hydrogen is considered to be mainly absorbed from the outermost surface of the conductive film 2. Therefore, in the present invention, in particular, the conductive film 2 preferably contains hydrogen in the range where the secondary ion intensity of hydrogen detected by the above analysis method is 1.0×10 2 cps or more, at least in its surface layer region. Thereby, even when the reflective mask manufactured from the reflective mask blank with the conductive film of the present invention is exposed to the exposure environment, deformation of the mask substrate due to stress change of the conductive film 2 on the back surface can be suppressed.

[0051] In addition, the conductive film 2 preferably contains hydrogen not only in the above-described surface layer region but also in other regions, and more preferably contains hydrogen throughout the film thickness direction. When the conductive film 2 is a laminated film, it is preferable that both the lower layer and the upper layer contain hydrogen. Thereby, deformation of the mask substrate due to stress change of the conductive film 2 can be further suppressed.

[0052] As a method for introducing hydrogen into the conductive film 2, hydrogen can be contained in the formed conductive film 2 by including hydrogen in the sputtering gas during the film formation of the conductive film 2. Further, hydrogen can be contained in the conductive film 2 by irradiating the conductive film 2 after film formation with hydrogen plasma.

[0053] Note that the secondary ion intensity of the above hydrogen is preferably 1.0×10 5 cps or less, and more preferably 1.0×10 4 cps or less. Thereby, the stress of the conductive film 2 can be adjusted to an appropriate range. Note that the unit of the secondary ion intensity, cps, stands for counts per sec and means the intensity of secondary ions detected per unit time. The unit in this specification is cps unless otherwise specified.

[0054] In the present invention, when hydrogen plasma irradiation is performed for 5 cycles under the conditions of Power 300W, H2 flow rate 100 sccm, and 100 sec / cycle, the difference in flatness of the substrate with the conductive film before and after hydrogen plasma irradiation is preferably 190 nm or less, more preferably 170 nm or less, and even more preferably 150 nm or less. The same applies to the substrate with the multilayer reflective film, the reflective mask blank, and the reflective mask described later.

[0055] As described above, according to the substrate with the conductive film of the present invention, even when the reflective mask manufactured from the reflective mask blank using this substrate with the conductive film is exposed to the exposure environment, deformation of the mask substrate due to stress change of the conductive film on the back surface can be suppressed.

[0056] [Substrate with a multilayer reflective film] Next, a substrate with a multilayer reflective film using the substrate with a conductive film of the present invention described above will be described. FIG. 2 is a cross-sectional view showing an embodiment of the substrate with a multilayer reflective film of the present invention. As shown in FIG. 2, in a substrate with a multilayer reflective film 20 according to an embodiment, a multilayer reflective film 3 that reflects EUV light, which is exposure light, is formed on a second main surface (the surface of substrate 1 in the illustrated state) facing the first main surface of the substrate with a conductive film 10.

[0057] The substrate with a multilayer reflective film 20 of the present embodiment is produced by forming a multilayer reflective film 3 that reflects, for example, EUV light of exposure light on the second main surface of the substrate with a conductive film 10.

[0058] The multilayer reflective film 3 is a multilayer film in which a low refractive index layer and a high refractive index layer are alternately laminated. Generally, as the multilayer reflective film 3, a multilayer film in which a thin film of a heavy element or its compound and a thin film of a light element or its compound are alternately laminated about 30 to 60 cycles is used. For example, as a multilayer reflective film for EUV light having a wavelength of 13 to 14 nm, a Mo / Si periodic multilayer film in which a Mo film and a Si film are alternately laminated about 40 cycles is preferably used. In addition, as a multilayer reflective film used in the region of EUV light, there are a Ru / Si periodic multilayer film, a Mo / Be periodic multilayer film, a Mo compound / Si compound periodic multilayer film, a Si / Nb periodic multilayer film, a Si / Mo / Ru periodic multilayer film, a Si / Mo / Ru / Mo periodic multilayer film, a Si / Ru / Mo / Ru periodic multilayer film, and the like. The material may be appropriately selected according to the exposure wavelength.

[0059] Generally, for the purpose of protecting the multilayer reflective film during the patterning or pattern modification of the absorber film, it is preferable to provide a protective film (which may also be referred to as a capping layer) on the above-mentioned multilayer reflective film 3. Such a protective film is formed of, for example, a material containing ruthenium as a main component. Examples of the material containing ruthenium as a main component include pure 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 in them. Note that containing substance A as a main component means containing 50 atomic% or more of substance A. Also, the film thickness of the protective film is preferably, for example, 1 nm or more. Also, the film thickness of the protective film is preferably 5 nm or less.

[0060] The film formation methods of the above-mentioned multilayer reflective film 3 and the protective film are not particularly limited, but usually, an ion beam sputtering method, a magnetron sputtering method, etc. are suitable.

[0061] [Reflective mask blank] Next, the reflective mask blank of the present invention will be described. The reflective mask blank of the present invention has a substrate having a first main surface and a second main surface facing the first main surface, a conductive film containing hydrogen formed on the first main surface, a multilayer reflective film formed on the second main surface, and an absorber film formed on the multilayer reflective film. The conductive film is a single-layer film or a laminated film including a lower layer and an upper layer formed on the lower layer. The single-layer film and the lower layer contain a metal and nitrogen or boron. The upper layer contains a metal and oxygen. When analyzing the conductive film 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 that the primary ion species is Cs + , the primary acceleration voltage is 3.0 kV, and the primary ion current is 25 nA, the secondary ion intensity of hydrogen detected is 1.0×10 2 cps or more.

[0062] Any of the regions with a 124-μm side can be, for example, a region including the center of the conductive film when viewed from above. When the surface of the conductive film is rectangular, the center of the conductive film is the intersection of the diagonals of the rectangle. Also, the center of any of the regions with a 124-μm side is the intersection of the diagonals and preferably coincides with the center of the conductive film in a top view. Further, it is more preferable that the center of any of the regions with a 124-μm side coincides with the center of the first main surface (back surface) of the substrate. The center of the first main surface of the substrate is the intersection of the diagonals of the first main surface.

[0063] FIG. 3 is a cross-sectional view showing an embodiment of the reflective mask blank of the present invention. As shown in FIG. 3, in a reflective mask blank 30 according to an embodiment of the present invention, an absorber film 5 is formed on the multilayer reflective film 3 of the multilayer-reflective-film substrate 20. Also, a conductive film 2 is formed on the first main surface of the substrate 1.

[0064] The reflective mask blank 30 is produced by forming an absorber film 5 that absorbs EUV light on the multilayer reflective film 3 (when the protective film is provided on the surface of the multilayer reflective film 3, that protective film) of the multilayer-reflective-film substrate 20.

[0065] The absorber film 5 has a function of absorbing, for example, EUV light which is exposure light. In the reflective mask 60 (see FIG. 6) manufactured using the reflective mask blank, it may have a desired reflectance difference between the reflected light by the multilayer reflective film 3 or the protective film on the multilayer reflective film 3 and the reflected light by the absorber film pattern 5a (see FIG. 6). For example, the reflectance of the absorber film 5 with respect to EUV light is selected to be between 0.1% and 40%. In addition to the reflectance difference, it may also have a desired phase difference between the reflected light by the multilayer reflective film 3 or the protective film and the reflected light by the absorber film pattern 5a. When there is a desired phase difference between the reflected light by the multilayer reflective film 3 or the protective film and the reflected light by the absorber film pattern 5a, the absorber film 5 in the reflective mask blank may be referred to as a phase shift film. When a desired phase difference is provided between the reflected light by the multilayer reflective film 3 or the protective film and the reflected light by the absorber film pattern 5a to improve the contrast, the phase difference is preferably set in the range of 150 degrees to 310 degrees, and the reflectance of the absorber film 5 is preferably set to be between 3% and 40%.

[0066] The absorber film 5 may be a single layer or a laminated structure. In the case of a laminated structure, it may be a laminated film of the same material or a laminated film of different materials. The laminated film can be such that the material and composition change stepwise and / or continuously in the film thickness direction. When the absorber film 5 is a laminated film, the absorber film 5 may include, for example, a layer (buffer layer) having etching selectivity with respect to the protective film at the position closest to the substrate in the film thickness direction.

[0067] As the material of the absorber film 5, for example, as long as it has a function of absorbing EUV light, can be processed by etching or the like, and has a high etching selectivity with respect to the multilayer reflective film 3 or the protective film, it is not particularly limited. The material of the absorber film 5 is preferably capable of being etched by dry etching of a chlorine (Cl)-based gas and / or a fluorine (F)-based gas. As those having the above functions, at least one metal selected from palladium (Pd), silver (Ag), platinum (Pt), gold (Au), iridium (Ir), tungsten (W), chromium (Cr), cobalt (Co), manganese (Mn), tin (Sn), tantalum (Ta), vanadium (V), nickel (Ni), hafnium (Hf), iron (Fe), copper (Cu), tellurium (Te), zinc (Zn), magnesium (Mg), germanium (Ge), aluminum (Al), rhodium (Rh), ruthenium (Ru), molybdenum (Mo), niobium (Nb), titanium (Ti), zirconium (Zr), yttrium (Y), and silicon (Si), an alloy containing two or more metals, or a compound thereof can be preferably used. The compound may contain oxygen (O), nitrogen (N), carbon (C), hydrogen (H), and / or boron (B) in the above metal or alloy.

[0068] The film thickness of the absorber film 5 is preferably in the range of, for example, about 30 nm to 100 nm. The method for forming the absorber film 5 is not particularly limited, but usually, a magnetron sputtering method, an ion beam sputtering method, or the like is suitable.

[0069] Also, the details regarding the configuration of the conductive film 2 in the reflective mask blank 30 are as described in the above substrate with a conductive film.

[0070] In the reflective mask blank 30, it is preferable that the single-layer film and the lower layer are formed in contact with the substrate 1.

[0071] In the reflective mask blank 30, the conductive film 2 preferably has a secondary ion intensity of hydrogen of 1.0×10 2 cps or more within a range of 5 nm in the film thickness direction from the outermost surface farthest from the substrate 1 of the conductive film 2.

[0072] In the reflective mask blank 30, a bottom layer containing metal and oxygen can be provided between the substrate 1 and the lower layer.

[0073] In the reflective mask blank 30, the conductive film 2 preferably contains tantalum or chromium.

[0074] In the reflective mask blank 30, the single-layer film and the lower layer preferably contain 10 atomic % or more and 40 atomic % or less of nitrogen.

[0075] FIG. 4 is a cross-sectional view showing another embodiment of the reflective mask blank of the present invention. As shown in FIG. 4, the reflective mask blank 40 of the present embodiment has the above-described 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.

[0076] FIG. 5 is a cross-sectional view showing still another embodiment of the reflective mask blank of the present invention. As shown in FIG. 5, the reflective mask blank 50 of the present embodiment has an etching mask film 6 formed on the absorber film 5.

[0077] The above-described etching mask film 6 has a masking function when patterning the absorber film 5, and is composed of a material having a different etching selectivity from the material of the uppermost layer of the absorber film 5. For example, when the absorber film 5 is a single Ta or a material containing Ta, the etching mask film 6 can use materials such as chromium, chromium compounds, silicon, or silicon compounds. Examples of chromium compounds include materials containing at least one element selected from Cr and N, O, C, and H. Examples of silicon compounds include materials containing at least one element selected from Si and N, O, C, and H, and materials such as metal silicon (metal silicide) and metal silicon compounds (metal silicide compounds) containing a metal in silicon or silicon compounds. Examples of metal silicon compounds include materials containing at least one element selected from a metal, Si, and N, O, C, and H. Also, when the absorber film 5 is a laminated film formed by sequentially forming a Ta-containing material and a Cr-containing material on the multilayer reflective film 3, the material of the etching mask film 6 can be selected from silicon, silicon compounds, metal silicides, metal silicide compounds, etc., which have different etching selectivities from the Cr-containing material.

[0078] Further, the reflective mask blank 50 according to the present embodiment (the same applies to the above-described reflective mask blanks 30 and 40) can be configured such that the absorber film 5 is composed of a laminated film of an uppermost layer made of a material having a different etching selectivity from each other and other layers, and the uppermost layer has a function as an etching mask film for the other layers.

[0079] As described above, the absorber film 5 in the reflective mask blanks 30, 40, and 50 according to the above-described embodiments is not limited to a single-layer film, and can be composed of a laminated film of the same material or a laminated film of different materials. Furthermore, it can be configured as a laminated film of the absorber film 5 such as the above-described laminated film or single-layer film and a film having a function as an etching mask film.

[0080] In addition, the reflective mask blanks 30, 40, and 50 according to the above-described embodiments also include an aspect in which a resist film is formed on the absorber film 5 or the etching mask film 6. Such a resist film is used when patterning the absorber film 5 in the reflective mask blank by lithography.

[0081] According to the reflective mask blanks 30, 40, and 50 of the present invention according to the above-described embodiments, even when the reflective mask manufactured from the reflective mask blank is exposed to an exposure environment, deformation of the mask substrate due to stress change of the conductive film on the back surface can be suppressed.

[0082] [Reflective Mask] The present invention also provides a reflective mask manufactured using the reflective mask blank 30 or the like. FIG. 6 is a cross-sectional view showing an embodiment of the reflective mask of the present invention. As shown in FIG. 6, the reflective mask 60 of the present embodiment has an absorber film pattern 5a obtained by patterning the absorber film 5 of the aforementioned reflective mask blank 40 by etching.

[0083] The method of patterning the absorber film 5, which becomes a transfer pattern, in the reflective mask blank 40 is most preferably the EUV (or electron beam) lithography method. That is, a resist film is formed by baking the electron beam drawing resist applied on the above-described reflective mask blank 40. The resist film is drawn and developed using an electron beam drawing apparatus to form a resist pattern corresponding to the transfer pattern on the resist film. Thereafter, the absorber film 5 is patterned using this resist pattern as a mask to form an absorber film pattern 5a. Thus, the reflective mask 60 shown in FIG. 6 is manufactured.

[0084] Note that the protective film 4 in the exposed area formed by forming the absorber film pattern 5a may be finally removed, but if it remains and does not affect the function as a reflective mask, it does not particularly need to be removed. Further, when manufacturing a reflective mask using the reflective mask blank 50 having the configuration including the etching mask film 6 described above, the etching mask film 6 may be finally removed, but if it remains and does not affect the function as a reflective mask, it does not particularly need to be removed.

[0085] [Method for manufacturing semiconductor device] Furthermore, the present invention also provides a method for manufacturing a semiconductor device. By using the reflective mask 60 of the present invention described above and exposing and transferring 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. By performing pattern transfer using the reflective mask 60 manufactured from the reflective mask blank with a conductive film of the present invention, even if the reflective mask 60 is exposed to the exposure environment during pattern transfer, deformation of the mask substrate due to stress change of the conductive film 2 on the back surface can be suppressed. Therefore, highly accurate pattern transfer can be performed without causing displacement of the transfer position during exposure.

[0086] As described in detail above, according to the present invention, it is possible to provide a substrate with a conductive film that can suppress deformation of the mask substrate due to stress change of the conductive film on the back surface even when the reflective mask manufactured from the reflective mask blank with a conductive film is exposed to the exposure environment. Also, according to the present invention, it is possible to provide a substrate with a multilayer reflective film, a reflective mask blank, and a reflective mask using the substrate with a conductive film. Even when the reflective mask manufactured from the reflective mask blank with a conductive film is exposed to the exposure environment, deformation of the mask substrate due to stress change of the conductive film on the back surface can be suppressed.

[0087] Furthermore, according to the present invention, by performing pattern transfer using this reflective mask, even when the reflective mask is exposed to the exposure environment during pattern transfer, deformation of the mask substrate due to stress change in the conductive film on the back surface can be suppressed. Therefore, high-precision pattern transfer can be performed without causing displacement of the transfer position during exposure. As a result, a high-quality semiconductor device with few defects can be manufactured.

Example

[0088] Hereinafter, embodiments of the present invention will be described more specifically with reference to examples. (Example 1) As a substrate, a SiO2-TiO2-based glass substrate (a 6-inch square substrate with a size of about 152.0 mm × about 152.0 mm and a thickness of about 6.35 mm) was prepared. This glass substrate has a smooth surface with a root mean square roughness (Rq) of 0.25 nm and flatness of 100 nm or less by mechanical polishing. The surface roughness was measured with an atomic force microscope (AFM), and the measurement area was 1 μm × 1 μm.

[0089] First, a conductive film made of TaNH was formed on the back surface (the first main surface) of the above substrate. The above substrate was placed in a sputtering apparatus, and using a tantalum (Ta) target, a mixed gas of argon (Ar), nitrogen (N2), and hydrogen (H2) (flow rate ratio (%) Ar:N2:H2 = 50:40:10) was used as the sputtering gas, and a TaNH film with a film thickness of 70 nm was formed by reactive sputtering. The nitrogen content of the TaNH film was 35 atomic%.

[0090] For the formed TaNH conductive film, using dynamic secondary ion mass spectrometry under the conditions where the primary ion species is Cs + , the primary acceleration voltage is 3.0 kV, and the primary ion current is 25 nA, the conductive film was analyzed in an arbitrary 124-μm square region within a 5-cm square including the center of the above substrate. As a result, the detected secondary ion intensity of hydrogen was 1.0×10 2 cps. The dynamic secondary ion mass spectrometry was performed in the negative ion detection mode using PHI ADEPT1010 (manufactured by ULVAC-PHI).

[0091] Next, on the substrate surface (second main surface) on the side opposite to the conductive film in another substrate with a conductive film fabricated in exactly the same manner as above, using an ion beam sputtering apparatus, a Si film (film thickness: 4.2 nm) and a Mo film (film thickness: 2.8 nm) were laminated 40 cycles with one cycle being a Si film and a Mo film, and finally a Si film (film thickness: 4 nm) was formed. Further, a protective film (film thickness: 2.5 nm) made of Ru was formed thereon to obtain a substrate with a multilayer reflective film.

[0092] Subsequently, using a DC magnetron sputtering apparatus, an absorber film composed of a laminated film of a TaBN film (film thickness: 56 nm) and a TaBO film (film thickness: 14 nm) was formed on the protective film of the substrate with the multilayer reflective film. Thus, a reflective mask blank was obtained.

[0093] The substrate flatness of the reflective mask blank thus obtained was measured. The measurement of the substrate flatness was performed in the same manner as in the case of the glass substrate. Next, in order to pseudo-reproduce the exposure environment of the reflective mask, the reflective mask blank was irradiated with hydrogen plasma under the conditions of Power 300 W, H2 flow rate 100 sccm, and 100 sec / cycle for 5 cycles, and the substrate flatness of the reflective mask blank after the hydrogen plasma irradiation was measured in the same manner as above. As a result, the difference in the substrate flatness before and after the hydrogen plasma irradiation of the reflective mask blank was 100 nm.

[0094] Next, a reflective mask was fabricated using another reflective mask blank fabricated in exactly the same manner as above. First, an electron beam drawing resist was applied onto the reflective mask blank and baked to form a resist film. A predetermined mask pattern was drawn on this resist film with an electron beam and developed to form a resist pattern.

[0095] Using this resist pattern as a mask, the TaBO film was etched and removed from the absorber film using a fluorine-based gas (CF4 gas), and the TaBN film was etched and removed using a chlorine-based gas (Cl2 gas) to form an absorber film pattern on the protective film. Furthermore, the resist pattern remaining on the absorber film pattern was removed to obtain a reflective mask.

[0096] The reflective mask of this example thus obtained was set in an exposure apparatus, and pattern transfer was performed onto a semiconductor substrate on which a resist film was formed. As a result, high-precision pattern transfer could be performed without causing any shift in the transfer position during exposure.

[0097] (Example 2) A conductive film made of TaH was formed on the back surface of the substrate prepared in the same manner as in Example 1. The above substrate was placed in a sputtering apparatus, and using a tantalum (Ta) target, a mixed gas of xenon (Xe) and hydrogen (H2) (flow rate ratio (%) Xe:H2 = 80:20) was used as the sputtering gas, and a TaH film with a thickness of 70 nm was formed by reactive sputtering. As a result of analyzing the TaH conductive film in the same manner as in Example 1, the secondary ion intensity of the detected hydrogen was 1.0×10 3 cps.

[0098] Next, on the substrate surface on the opposite side of the conductive film in another substrate with a conductive film fabricated in exactly the same manner as above, a multilayer reflective film, a protective film, and an absorber film were formed in sequence in the same manner as in Example 1 to obtain a reflective mask blank for Example 2.

[0099] As a result of confirming the difference in substrate flatness before and after hydrogen plasma irradiation for the obtained reflective mask blank in the same manner as in Example 1, it was 80 nm. Next, using another reflective mask blank fabricated in exactly the same manner as above, a reflective mask for Example 2 was fabricated in the same manner as in Example 1.

[0100] The reflective mask of Example 2 thus obtained was set in an exposure apparatus, and pattern transfer was performed onto a semiconductor substrate on which a resist film was formed. As a result, high-precision pattern transfer could be performed without causing any displacement of the transfer position during exposure.

[0101] (Example 3) A conductive film composed of a TaNH film as the lower layer and a TaOH film as the upper layer was formed on the back surface of the substrate prepared in the same manner as in Example 1. The above substrate was placed in a sputtering apparatus, and using a tantalum (Ta) target, a mixed gas of xenon (Xe), nitrogen (N2), and hydrogen (H2) (flow rate ratio (%) Xe:N2:H2 = 33:56:11) was used as the sputtering gas, and a TaNH film with a film thickness of 60 nm was formed by reactive sputtering. The nitrogen content of the TaNH film was 35 atomic %. Subsequently, using the same tantalum (Ta) target, a mixed gas of xenon (Xe), oxygen (O2), and hydrogen (H2) (flow rate ratio (%) Xe:O2:H2 = 44:37:19) was used as the sputtering gas, and a TaOH film with a film thickness of 10 nm was formed. The oxygen content of the TaOH film was 50 atomic %.

[0102] As a result of analyzing the conductive film composed of the TaNH film and the TaOH film in the same manner as in Example 1, the secondary ion intensity of hydrogen detected for the TaNH film was 1.0×10 2 cps, and the secondary ion intensity of hydrogen detected for the TaOH film was 1.0×10 3 cps.

[0103] Next, on the surface of the substrate on the side opposite to the conductive film in another substrate with a conductive film fabricated in exactly the same manner as above, a multilayer reflective film, a protective film, and an absorber film were sequentially formed in the same manner as in Example 1 to obtain a reflective mask blank of Example 3.

[0104] As a result of confirming the difference in substrate flatness before and after hydrogen plasma irradiation for the obtained reflective mask blank in the same manner as in Example 1, it was 50 nm. Next, using another reflective mask blank fabricated in exactly the same manner as described above, a reflective mask of Example 3 was fabricated in the same manner as in Example 1.

[0105] The reflective mask of Example 3 thus obtained was set in an exposure apparatus, and pattern transfer was performed onto a semiconductor substrate on which a resist film was formed. As a result, high-precision pattern transfer could be performed without causing any shift in the transfer position during exposure.

[0106] (Example 4) On the back surface of the substrate prepared in the same manner as in Example 1, a conductive film composed of a TaBH film as the lower layer and a TaBOH film as the upper layer was formed. The above substrate was placed in a sputtering apparatus, and using a TaB target, a mixed gas of xenon (Xe) and hydrogen (H2) (flow rate ratio (%) Xe:H2 = 80:20) was used as the sputtering gas, and a TaBH film with a thickness of 60 nm was formed by reactive sputtering. The boron content of the TaBH film was 16 atomic %. Subsequently, using the same TaB target, a mixed gas of argon (Ar), oxygen (O2), and hydrogen (H2) (flow rate ratio (%) Ar:O2:H2 = 61:30:9) was used as the sputtering gas, and a TaBOH film with a thickness of 10 nm was formed. The TaBOH film contained 10 atomic % boron and 50 atomic % oxygen.

[0107] As a result of analyzing the conductive film composed of the TaBH film and the TaBOH film in the same manner as in Example 1, the secondary ion intensity of hydrogen detected for the TaBH film was 1.0×10 2 cps, and the secondary ion intensity of hydrogen detected for the TaBOH film was 1.0×10 2 cps.

[0108] Next, on the surface of the substrate on the opposite side of the conductive film in another substrate with a conductive film fabricated in exactly the same manner as described above, a multilayer reflective film, a protective film, and an absorber film were sequentially formed in the same manner as in Example 1 to obtain a reflective mask blank of Example 4.

[0109] With respect to the obtained reflective mask blank, the difference in substrate flatness before and after hydrogen plasma irradiation was confirmed in the same manner as in Example 1, and the result was 25 nm. Next, using another reflective mask blank fabricated in exactly the same manner as described above, a reflective mask of Example 4 was fabricated in the same manner as in Example 1.

[0110] The reflective mask of Example 4 thus obtained was set in an exposure apparatus, and pattern transfer onto a semiconductor substrate on which a resist film was formed was performed. As a result, high-precision pattern transfer could be performed without causing any displacement in the transfer position during exposure.

[0111] (Example 5) A conductive film made of CrONH was formed on the back surface of the substrate prepared in the same manner as in Example 1. The above substrate was placed in a sputtering apparatus, and using a chromium (Cr) target, a mixed gas of argon (Ar), oxygen (O2), nitrogen (N2), and hydrogen (H2) (flow rate ratio (%) Ar:O2:N2:H2 = 70:14:7:9) was used as the sputtering gas, and a CrONH film with a thickness of 70 nm was formed by reactive sputtering. The CrONH film contained 15 atomic% oxygen and 10 atomic% nitrogen. As a result of analyzing the above CrONH conductive film in the same manner as in Example 1, the secondary ion intensity of the detected hydrogen was 1.0×10 2 cps.

[0112] Next, on the substrate surface on the opposite side of the conductive film in another substrate with a conductive film fabricated in exactly the same manner as described above, a multilayer reflective film, a protective film, and an absorber film were formed in sequence in the same manner as in Example 1 to obtain a reflective mask blank of Example 5.

[0113] With respect to the obtained reflective mask blank, the difference in substrate flatness before and after hydrogen plasma irradiation was confirmed in the same manner as in Example 1, and the result was 100 nm. Next, using another reflective mask blank fabricated in exactly the same manner as described above, a reflective mask of Example 5 was fabricated in the same manner as in Example 1.

[0114] The reflective mask of Example 5 thus obtained was set in an exposure apparatus, and pattern transfer was performed onto a semiconductor substrate on which a resist film was formed. As a result, high-precision pattern transfer could be performed without causing any deviation in the transfer position during exposure.

[0115] (Comparative Example 1) A conductive film made of TaN was formed on the back surface of the substrate prepared in the same manner as in Example 1. The above substrate was placed in a sputtering apparatus, and using a tantalum (Ta) target, a mixed gas of xenon (Xe) and nitrogen (N2) (flow rate ratio (%) Xe:N2 = 37.5:62.5) was used as a sputtering gas, and a TaN film with a film thickness of 70 nm (composition ratio Ta:N = 65 atomic%:35 atomic%) was formed by reactive sputtering. As a result of analyzing the TaN conductive film in the same manner as in Example 1, the secondary ion intensity of the detected hydrogen was 1.0×10 1 cps.

[0116] Next, on the substrate surface on the opposite side of the conductive film in another substrate with a conductive film produced in exactly the same manner as above, a multilayer reflective film, a protective film, and an absorber film were sequentially formed in the same manner as in Example 1 to obtain a reflective mask blank of Comparative Example 1.

[0117] As a result of confirming the difference in substrate flatness before and after hydrogen plasma irradiation for the obtained reflective mask blank in the same manner as in Example 1, it was 200 nm, and the deformation of the mask blank substrate was large. Next, using another reflective mask blank produced in exactly the same manner as above, a reflective mask of Comparative Example 1 was produced in the same manner as in Example 1.

[0118] The reflective mask of Comparative Example 1 thus obtained was set in an exposure apparatus, and pattern transfer was performed onto a semiconductor substrate on which a resist film was formed. As a result, deviation in the transfer position occurred during exposure, and high-precision pattern transfer could not be performed. This is presumably because the mask substrate was deformed due to a stress change in the conductive film caused by hydrogen intrusion into the conductive film of the reflective mask, resulting in deviation in the transfer position during exposure.

[0119] (Comparative Example 2) A conductive film made of CrN was formed on the back surface of the substrate prepared in the same manner as in Example 1. The substrate was placed in a sputtering apparatus, and using a chromium (Cr) target, a mixed gas of argon (Ar) and nitrogen (N2) (flow rate ratio (%) Ar:N2 = 60:40) was used as the sputtering gas, and a CrN film with a film thickness of 70 nm (composition ratio Cr:N = 75 atomic%:25 atomic%) was formed by reactive sputtering. As a result of analyzing the CrN conductive film in the same manner as in Example 1, the secondary ion intensity of the detected hydrogen was 1.0×10 1 cps.

[0120] Next, on the surface of the substrate on the side opposite to the conductive film in another substrate with a conductive film produced in exactly the same manner as above, in the same manner as in Example 1, a multilayer reflective film, a protective film, and an absorber film were sequentially formed to obtain a reflective mask blank of Comparative Example 2.

[0121] As a result of confirming the difference in substrate flatness before and after hydrogen plasma irradiation for the obtained reflective mask blank in the same manner as in Example 1, it was 200 nm, and the deformation of the mask blank substrate was large. Next, using another reflective mask blank produced in exactly the same manner as above, in the same manner as in Example 1, a reflective mask of Comparative Example 2 was produced.

[0122] The reflective mask of Comparative Example 2 thus obtained was set in an exposure apparatus, and pattern transfer was performed onto a semiconductor substrate on which a resist film was formed. As a result, a shift in the transfer position occurred during exposure, and high-precision pattern transfer could not be performed. This is considered to be due to the deformation of the mask substrate caused by a change in the stress of the conductive film due to hydrogen intrusion into the conductive film of the reflective mask, resulting in a shift in the transfer position during exposure.

[0123] As is apparent from the embodiments described above, according to the substrate with a conductive film of the present invention, even when the reflective mask manufactured from the reflective mask blank using this substrate with a conductive film is exposed to an exposure environment, deformation of the mask substrate due to stress change of the conductive film on the back surface can be suppressed. Therefore, by performing pattern transfer using this reflective mask, even when the reflective mask is exposed to the exposure environment during pattern transfer, deformation of the mask substrate due to stress change of the conductive film on the back surface can be suppressed. Thus, high-precision pattern transfer can be performed without causing displacement of the transfer position during exposure.

Explanation of Reference Numerals

[0124] 1 Substrate 2 Conductive film 3 Multilayer reflective film 4 Protective film 5 Absorber film 6 Etching mask film 10 Substrate with a conductive film 20 Substrate with a multilayer reflective film 30, 40, 50 Reflective mask blank 60 Reflective mask

Claims

1. A substrate with a conductive film, comprising: a substrate; a conductive film containing hydrogen, formed on a first main surface of the substrate; the conductive film being a single-layer film or a laminated film including a lower layer and an upper layer formed on the lower layer; the single-layer film and the lower layer containing a metal and nitrogen or boron; the upper layer containing a metal and oxygen; The primary ion species is Cs ＋ When the conductive film is 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 that the primary acceleration voltage is 3.0 kV and the primary ion current is 25 nA, the secondary ion intensity of hydrogen detected is 1.0×10 ２ cps or more, and the substrate is characterized by having a conductive film

2. The substrate with a conductive film according to Claim 1, wherein the single-layer film and the lower layer are formed in contact with the substrate.

3. The conductive film has a secondary ion intensity of hydrogen of 1.0×10 ２ cps or more within a range of 5 nm in the film thickness direction from the outermost surface of the conductive film farthest from the substrate. The substrate with a conductive film according to claim 1 or 2, characterized in that.

4. The substrate with a conductive film according to Claim 1 or 2, further comprising a bottom layer containing a metal and oxygen between the substrate and the lower layer.

5. The substrate with a conductive film according to Claim 1 or 2, wherein the conductive film contains tantalum or chromium.

6. The substrate with a conductive film according to Claim 1 or 2, wherein the single-layer film and the lower layer contain nitrogen in an amount of 10 atomic% or more and 40 atomic% or less.

7. A substrate with a multilayer reflective film, comprising: a multilayer reflective film formed on a second main surface facing the first main surface of the substrate with a conductive film according to Claim 1 or 2.

8. A reflective mask blank, comprising: an absorber film formed on the multilayer reflective film of the substrate with a multilayer reflective film according to Claim 7.

9. A reflective mask, comprising: an absorber film pattern obtained by patterning the absorber film of the reflective mask blank according to Claim 8.

10. A method for manufacturing a semiconductor device, comprising a step of transferring the absorber film pattern to a transfer target by exposure using the reflective mask according to Claim 9.

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