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

Abstract

To solve the above problems, the substrate with a multilayer reflective film of the present application has a substrate, a multilayer reflective film provided on the substrate, and a protective film provided on the multilayer reflective film, wherein the protective film contains ruthenium (Ru) and at least one additive material selected from the group consisting of aluminum (Al), yttrium (Y), zirconium (Zr), rhodium (Rh), and hafnium (Hf), and the content of the additive material is 5 atomic % or more and less than 50 atomic %.

Description

TECHNICAL FIELD

[0001] The present application relates to a reflective mask used for manufacturing a semiconductor device or the like, and a multilayer reflective film-equipped substrate used for manufacturing a reflective mask, a reflective mask blank. In addition, the present application relates to a manufacturing method of a semiconductor device using the above-described reflective mask. BACKGROUND

[0002] With further requirements for high density and high precision of ultra LSI devices in recent years, an EUV lithography technique using an exposure technique of EUV (Extreme Ultra Violet, hereinafter referred to as EUV) light is expected. The EUV light refers to light of a wavelength band in a soft X-ray region or a vacuum ultraviolet region, and specifically, light of a wavelength of about 0.2 to 100 nm.

[0003] The reflective mask has a multilayer reflective film for reflecting exposure light formed on a substrate, and an absorber pattern as a pattern-shaped absorber film for absorbing exposure light formed on the multilayer reflective film. Light incident to the reflective mask mounted on an exposure machine for performing pattern transfer on a semiconductor substrate is absorbed at a portion having the absorber pattern and is reflected by the multilayer reflective film at a portion not having the absorber pattern. The light image reflected by the multilayer reflective film is transferred to a semiconductor substrate such as a silicon wafer after passing through a reflection optical system.

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

[0005] As the multilayer reflective film, a multilayer film in which elements having different refractive indexes are periodically stacked is generally used. For example, as a multilayer reflective film for EUV light of a wavelength of 13 to 14 nm, a Mo / Si periodic stacked film in which Mo films and Si films are alternately stacked for about 40 cycles can be preferably used.

[0006] As the reflective mask for the EUV lithography technique, there is, for example, a reflective mask described in Patent Literature 1. Patent Literature 1 describes a reflective photomask having a substrate, a reflection layer formed on the substrate, a buffer layer formed of a ruthenium film formed on the reflection layer, and an absorber pattern having a given pattern shape and formed on the buffer layer, the reflection layer being formed of a multilayer film in which two different films are alternately stacked, and the absorber pattern being formed of a material capable of absorbing soft X-rays. The buffer layer described in Patent Literature 1 is also generally referred to as a protective film.

[0007] Patent Document 2 describes a substrate with a multilayer reflective film on a substrate, the multilayer reflective film reflecting exposure light. In addition, Patent Document 2 describes that a protective film for protecting the multilayer reflective film is formed on the multilayer reflective film, and the protective film is formed by sequentially stacking a reflectance reduction suppression layer, a barrier layer, and an etching stop layer. In addition, Patent Document 2 describes that the etching stop layer is formed of ruthenium (Ru) or an alloy thereof, and as the alloy of ruthenium, a ruthenium niobium (RuNb) alloy, a ruthenium zirconium (RuZr) alloy, a ruthenium rhodium (RuRh) alloy, a ruthenium cobalt (RuCo) alloy, and a ruthenium rhenium (RuRe) alloy can be cited.

[0008] Patent Documents 3 and 4 describe a substrate with a multilayer reflective film, which has a substrate, a multilayer reflective film, and a Ru-based protective film for protecting the multilayer reflective film formed on the multilayer reflective film. Patent Documents 3 and 4 describe that a surface layer of the multilayer reflective film on the opposite side of the substrate is a layer containing Si.

[0009] Patent Document 3 describes that a barrier layer that prevents the transfer of Si to the Ru-based protective film is provided between the multilayer reflective film and the Ru-based protective film. Patent Document 3 describes that, as a material constituting the Ru-based protective film 18, Ru and an alloy material thereof can be cited, and as the alloy of Ru, a Ru compound containing Ru and at least one metal element selected from the group consisting of Nb, Zr, Rh, Ti, Co, and Re is preferable.

[0010] In addition, Patent Document 4 describes that the Ru-based protective film contains a Ru compound containing Ru and Ti, and the Ru compound contains more Ru than a RuTi phase having a stoichiometric composition.

[0011] Prior Art Documents

[0012] Patent Documents

[0013] Patent Document 1: Japanese Patent Application Publication No. 2002-122981

[0014] Patent Document 2: Japanese Patent Application Publication No. 2014-170931

[0015] Patent Document 3: International Publication No. 2015 / 012151

[0016] Patent Document 4: International Publication No. 2015 / 037564 SUMMARY

[0017] PROBLEMS TO BE SOLVED BY THE INVENTION

[0018] In the manufacturing process of a reflective mask, an absorber film is etched through a resist film and / or an etching mask film to form an absorber pattern. In order to make the shape of the absorber pattern follow the design, some over-etching is required when the absorber film is etched. Therefore, the film under the absorber film (film on the substrate side) is also etched. When over-etching the absorber film, a protective film is provided to prevent the multilayer reflective film under the absorber film from being damaged. Therefore, the protective film is required to have high resistance to the etching gas for the absorber film.

[0019] As a material for the protective film having high resistance to the etching gas for the absorber film, Ru or RuNb has been used, for example. In the case where the etching mask film formed on the absorber film is a Cr-based material, a mixed gas of chlorine and oxygen is used as the etching gas in order to peel off the etching mask film. The protective film of Ru or RuNb has low resistance to the mixed gas containing oxygen. Therefore, when the etching mask film is peeled off, the multilayer reflective film formed under the protective film can be damaged. In addition, the protective film damaged when the etching mask film is peeled off can have insufficient resistance in the subsequent correction process of the absorber pattern.

[0020] In EUV lithography technology in the manufacturing of semiconductor devices, there are few substances transparent to exposure light. Therefore, the EUV protective film for preventing the attachment of foreign matter to the mask pattern surface of a reflective mask is not simple in technology. In addition, in EUV lithography technology, exposure contamination such as the deposition of carbon film on the mask or the growth of oxide film can be caused by EUV exposure. Therefore, at the stage where the mask is used for the manufacturing of semiconductor devices, the foreign matter and contaminants on the mask need to be removed by cleaning with a cleaning solution such as a sulfuric acid / hydrogen peroxide mixed solution (SPM) repeatedly. However, the protective film of Ru or RuNb has a problem of insufficient resistance to SPM cleaning.

[0021] A thin film of Ru or RuNb is easily crystallized and has high crystallinity. A thin film with high crystallinity is inferior to an amorphous thin film in terms of density. Therefore, it is considered that the protective film of Ru or RuNb has a problem of low resistance to a given etching gas and insufficient resistance to cleaning such as SPM cleaning.

[0022] Therefore, an object of the present application is to provide a reflective mask having a protective film with high resistance to an etching gas and high resistance to cleaning. In addition, an object of the present application is to provide a multilayer reflective film-equipped substrate for manufacturing a reflective mask and a reflective mask blank, the reflective mask having a protective film with high resistance to an etching gas and high resistance to cleaning.

[0023] Method for solving the problem

[0024] To solve the above problems, the present application includes the following aspects.

[0025] (Aspect 1)

[0026] Aspect 1 of the present application relates to a substrate with a multilayer reflective film, which has a substrate, a multilayer reflective film provided on the substrate, and a protective film provided on the multilayer reflective film,

[0027] wherein the protective film contains ruthenium (Ru) and contains at least one additive material selected from the group consisting of magnesium (Mg), aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), germanium (Ge), zirconium (Zr), niobium (Nb), molybdenum (Mo), rhodium (Rh), hafnium (Hf), and tungsten (W), and the content of the additive material is 5 atomic % or more and less than 50 atomic %.

[0028] (Aspect 2)

[0029] Aspect 2 of the present application relates to the substrate with a multilayer reflective film according to Aspect 1, wherein

[0030] the protective film includes a first layer and a second layer from the side of the substrate,

[0031] the first layer contains ruthenium (Ru) and contains at least one of magnesium (Mg), aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), germanium (Ge), zirconium (Zr), niobium (Nb), molybdenum (Mo), rhodium (Rh), hafnium (Hf), and tungsten (W),

[0032] the second layer contains the ruthenium (Ru) and the additive material.

[0033] (Aspect 3)

[0034] Aspect 3 of the present application relates to the substrate with a multilayer reflective film according to Aspect 1 or 2, wherein the protective film, the first layer, or the second layer further contains nitrogen (N).

[0035] (Aspect 4)

[0036] Aspect 4 of the present application relates to the substrate with a multilayer reflective film according to any one of Aspects 1 to 3, wherein the Ru content of the second layer is less than the Ru content of the first layer.

[0037] (Aspect 5)

[0038] Aspect 5 of the present application relates to a reflective mask blank, which has an absorber film on the protective film of the substrate with a multilayer reflective film according to any one of Aspects 1 to 4.

[0039] (Aspect 6)

[0040] Aspect 6 of the present application relates to the reflective mask blank according to Aspect 5, which includes an etching mask film containing chromium (Cr) on the absorber film.

[0041] (Embodiment 7)

[0042] Embodiment 7 of the present application relates to a reflective mask including an absorber pattern obtained by patterning the above-mentioned absorber film in the reflective mask blank of Embodiment 5 or 6.

[0043] (Embodiment 8)

[0044] Embodiment 8 of the present application relates to a method for manufacturing a reflective mask, the method including:

[0045] patterning the above-mentioned etching mask film of the reflective mask blank of Embodiment 6 to form an etching mask pattern;

[0046] patterning the above-mentioned absorber film using the above-mentioned etching mask pattern as a mask to form an absorber pattern;

[0047] removing the above-mentioned etching mask pattern using a mixed gas of a chlorine-based gas and oxygen.

[0048] (Embodiment 9)

[0049] Embodiment 9 of the present application relates to a method for manufacturing a semiconductor device, the method including:

[0050] providing the reflective mask of Embodiment 7 to an exposure device having an exposure light source that emits EUV light to transfer a transfer pattern to a resist film formed on a transfer substrate.

[0051] Effects of the Invention

[0052] According to the present application, it is possible to provide a reflective mask having a protective film that is highly resistant to etching gas and highly resistant to cleaning. In addition, according to the present application, it is possible to provide a substrate with a multilayer reflective film and a reflective mask blank for manufacturing a reflective mask having a protective film that is highly resistant to etching gas and highly resistant to cleaning. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 is a cross-sectional schematic view of an example of the substrate with a multilayer reflective film of the present embodiment.

[0054] Figure 2 is a cross-sectional schematic view of another example of the substrate with a multilayer reflective film of the present embodiment.

[0055] Figure 3 is a cross-sectional schematic view of an example of the reflective mask blank of the present embodiment.

[0056] Figure 4 is a cross-sectional schematic view of another example of the reflective mask blank of the present embodiment.

[0057] Figure 5 FIG. 2 is a graph showing the relationship between the content of Rh and the etching rate of the protective film using a mixed gas.

[0058] Figure 6 FIG. 3 is a graph showing the measurement results of the diffraction X-ray intensity (CPS) with respect to the diffraction angle 2Θ.

[0059] Figure 7 FIG. 4 is a graph showing the measurement results of the diffraction X-ray intensity (CPS) with respect to the diffraction angle 2Θ for a film into which nitrogen (N) was introduced at the time of film formation.

[0060] Figure 8 FIG. 5 is a process chart showing an example of a manufacturing method of a reflective mask of the present embodiment in a cross-sectional schematic view.

[0061] Symbol Explanation

[0062] 1 substrate for mask blank (substrate)

[0063] 2 back surface conductive film

[0064] 5 multilayer reflective film

[0065] 6 protective film

[0066] 7 absorber film

[0067] 7a absorber pattern

[0068] 8 resist film

[0069] 8a resist pattern

[0070] 9 etching mask film

[0071] 9a etching mask pattern

[0072] 62 first layer

[0073] 64 second layer

[0074] 100 reflective mask blank

[0075] 110 substrate with multilayer reflective film

[0076] 200 reflective mask DETAILED DESCRIPTION

[0077] Hereinafter, embodiments of the present application will be specifically described with reference to the drawings. Note that the following embodiments are examples for specifically describing the present application, and the present application is not limited to the following embodiments.

[0078] Figure 1is a cross-sectional schematic view showing an example of the multilayer reflection film-equipped substrate 110 of the present embodiment. Figure 1 The multilayer reflection film-equipped substrate 110 shown in FIG. 1A has the multilayer reflection film 5 and the protective film 6. Note that the multilayer reflection film-equipped substrate 110 can further have other thin films such as the back surface conductive film 2.

[0079] Figure 2 is a cross-sectional schematic view of the same multilayer reflection film-equipped substrate 110. However, in the multilayer reflection film-equipped substrate 110 shown in FIG. 1B, the protective film 6 includes the first layer 62 and the second layer 64. Figure 1 Figure 2

[0080] Figure 3 is a cross-sectional schematic view showing an example of the reflective mask blank 100 of the present embodiment. Figure 3 The reflective mask blank 100 shown in FIG. 2A has the back surface conductive film 2, the multilayer reflection film 5, the protective film 6, and the absorber film 7. Note that the reflective mask blank 100 can further have other thin films such as the resist film 8.

[0081] Figure 4 is a cross-sectional schematic view showing an example of the reflective mask blank 100 further having the etching mask film 9 in addition to the components shown in FIG. 2A. Note that the reflective mask blank 100 can further have other thin films such as the resist film 8. Figure 3 In the present specification, a main surface of the mask blank substrate 1, which is to be formed with the multilayer reflection film 5, is sometimes referred to as a "front-side main surface" (or a "first main surface"). In addition, a main surface of the mask blank substrate 1, which is not formed with the multilayer reflection film 5, is sometimes referred to as a "back-side main surface" (or a "second main surface"). The back surface conductive film 2 can be formed on the "back-side main surface" (or the "second main surface").

[0082] In the present specification, the phrase "provided with (having) a given thin film on a main surface of the mask blank substrate 1" includes a case where another film is provided between the mask blank substrate 1 and the given thin film, in addition to a case where the given thin film is provided in contact with the main surface of the mask blank substrate 1. In addition, for example, the phrase "film B is provided on film A" includes a case where another film is provided between film A and film B, in addition to a case where film A and film B are provided in direct contact with each other. In the present specification, for example, the phrase "film A and film B are provided in contact with each other" means that film A and film B are provided in direct contact with each other without another film interposed therebetween.

[0083]

[0084] ​​​Next, surface roughness (Rms) as a parameter representing the surface morphology of the substrate 1 for a mask blank, and the surface morphology of the surface of the thin film constituting the reflective mask blank 100 and the like will be described.

[0085] Rms (Root mean square) as an index of representative surface roughness is a root mean square roughness, and is a square root of a value obtained by averaging the square of the deviation from the average line to the measurement curve. Rms is represented by the following formula (1).

[0086] [mathematical formula 1]

[0087]

[0088] In formula (1), 1 is a reference length, and Z is a height from the average line to the measurement curve.

[0089] Rms has been used for management of the surface roughness of the substrate 1 for a mask blank in the past, and the surface roughness can be grasped as a numerical value.

[0090] <Substrate 110 with Multilayer Reflective Film>

[0091] The substrate 1 and each thin film of the substrate 110 with a multilayer reflective film, which is one of the substrates 1 with a thin film according to the present embodiment, will be described.

[0092] <Substrate 1>

[0093] The substrate 1 in the substrate 110 with a multilayer reflective film according to the present embodiment needs to prevent occurrence of deformation of the absorber pattern 7a caused by heat at the time of EUV exposure. Therefore, as the substrate 1, a substrate having a low thermal expansion coefficient in the range of 0 ± 5 ppb / °C is preferably used. As a material having a low thermal expansion coefficient in this range, for example, SiO2-TiO2-based glass, a multi-component-based glass ceramic, and the like can be used.

[0094] As for the first main surface (front main surface) of the substrate 1 on the side on which the transfer pattern (formed of the absorber film 7 described later) is to be formed, at least from the viewpoint of achieving pattern transfer precision and positional precision, surface processing is performed to achieve a given flatness. In the case of EUV exposure, in a region of 132 mm x 132 mm of the first main surface of the substrate 1 on the side on which the transfer pattern is to be formed, the flatness is preferably 0.1 μm or less, more preferably 0.05 μm or less, and further preferably 0.03 μm or less. In addition, as for the second main surface (back main surface) on the side opposite to the side on which the absorber film 7 is to be formed, it is a surface on which electrostatic adsorption occurs when set in the exposure apparatus. The flatness of the second main surface in a region of 132 mm x 132 mm is preferably 0.1 μm or less, more preferably 0.05 μm or less, and further preferably 0.03 μm or less. Note that the flatness of the second main surface of the reflective mask blank 100 in a region of 142 mm x 142 mm is preferably 1 μm or less, more preferably 0.5 μm or less, and further preferably 0.3 μm or less.

[0095] In addition, the degree of surface smoothness of the substrate 1 is also an important item. The surface roughness of the first main surface on which the absorber pattern 7a for transfer is to be formed is preferably 0.15 nm or less in terms of root mean square roughness (Rms), and more preferably 0.10 nm or less in terms of Rms. Note that the surface smoothness can be measured using an atomic force microscope.

[0096] In addition, in order to prevent deformation caused by film stress of a film (multilayer reflective film 5 or the like) formed on the substrate 1, it is preferable that the substrate 1 have high rigidity. It is particularly preferable that the substrate 1 have a high Young's modulus of 65 GPa or more.

[0097] <<Substrate Film>>

[0098] The multilayer reflective film-equipped substrate 110 of the present embodiment can have a substrate film on the surface of the substrate 1. The substrate film is a thin film formed between the substrate 1 and the multilayer reflective film 5. By having the substrate film, charging at the time of mask pattern defect inspection using an electron beam can be prevented, and the multilayer reflective film 5 has few phase defects, and thus high surface smoothness can be obtained.

[0099] As the material of the substrate film, a material containing ruthenium or tantalum as a main component is preferably used. For example, it can be a Ru metal single substance, a Ta metal single substance, or a Ru alloy or a Ta alloy containing titanium (Ti), niobium (Nb), molybdenum (Mo), zirconium (Zr), yttrium (Y), boron (B), lanthanum (La), cobalt (Co), and / or rhenium (Re) or the like in Ru or Ta. The film thickness of the substrate film is preferably in the range of 1 nm to 10 nm, for example.

[0100] << Multilayer reflective film 5 >>

[0101] The multilayer reflective film-equipped substrate 110 of the embodiment includes the multilayer reflective film 5. The multilayer reflective film 5 imparts a function of reflecting EUV light in the reflective mask 200. The multilayer reflective film 5 is a multilayer film in which layers each of which has an element with different refractive index as a main component are periodically laminated.

[0102] In general, as the multilayer reflective film 5, a multilayer film in which thin films of light elements or compounds thereof as high refractive index materials (high refractive index layers) and thin films of heavy elements or compounds thereof as low refractive index materials (low refractive index layers) are alternately laminated for about 40 to 60 periods can be used.

[0103] The multilayer film used as the multilayer reflective film 5 can be one in which a high refractive index layer / low refractive index layer lamination structure in which a high refractive index layer and a low refractive index layer are sequentially laminated from the substrate 1 side is laminated as one period for a plurality of periods, or one in which a low refractive index layer / high refractive index layer lamination structure in which a low refractive index layer and a high refractive index layer are sequentially laminated from the substrate 1 side is laminated as one period for a plurality of periods. Note that it is preferable that the surface layer of the multilayer reflective film 5 on the side opposite to the substrate 1, that is, the surface layer of the multilayer reflective film 5 on the side opposite to the substrate 1 be a high refractive index layer. In the above-described multilayer film, when the high refractive index layer / low refractive index layer lamination structure in which a high refractive index layer and a low refractive index layer are sequentially laminated from the substrate 1 side is laminated as one period for a plurality of periods, the uppermost layer is a low refractive index layer. In this case, the low refractive index layer is likely to be oxidized when it constitutes the surface of the multilayer reflective film 5, resulting in a decrease in reflectance of the reflective mask 200. Therefore, it is preferable that a high refractive index layer be further formed on the low refractive index layer of the uppermost layer to make the multilayer reflective film 5. On the other hand, in the above-described multilayer film, when the low refractive index layer / high refractive index layer lamination structure in which a low refractive index layer and a high refractive index layer are sequentially laminated from the substrate 1 side is laminated as one period for a plurality of periods, the uppermost layer is a high refractive index layer. Therefore, in this case, it is not necessary to form a further high refractive index layer.

[0104] As the high refractive index layer, a layer containing silicon (Si) can be used. As the material containing Si, a Si compound containing boron (B), carbon (C), nitrogen (N), oxygen (O), and / or hydrogen (H) in Si can be used in addition to Si single substance. By using the high refractive index layer containing Si, a reflection-type mask 200 having excellent reflectance of EUV light can be obtained. In addition, as the low refractive index layer, a metal single substance or an alloy selected from molybdenum (Mo), ruthenium (Ru), rhodium (Rh), and platinum (Pt) can be used. In addition, boron (B), carbon (C), nitrogen (N), oxygen (O), and / or hydrogen (H) can be added to these metal single substances or alloys. In the substrate 110 with a multilayer reflective film of the present embodiment, it is preferable that the low refractive index layer be a molybdenum (Mo) layer and the high refractive index layer be a silicon (Si) layer. As the multilayer reflective film 5 for reflecting EUV light having a wavelength of, for example, 13 nm to 14 nm, a Mo / Si periodic layer stack film in which Mo layers and Si layers are alternately stacked for about 40 to 60 periods can be preferably used. Note that the high refractive index layer as the uppermost layer of the multilayer reflective film 5 can be formed of silicon (Si), and a silicon oxide layer containing silicon and oxygen can be formed between the uppermost layer (Si) and the protective film 6. In this structure, mask cleaning resistance can be improved.

[0105] The reflectance of the multilayer reflective film 5 alone is generally 65% or more, and the upper limit is generally 73%. Note that the film thickness and the period of each layer of the multilayer reflective film 5 can be appropriately selected depending on the exposure wavelength. Specifically, the film thickness and the period of each layer of the multilayer reflective film 5 can be selected in a manner to satisfy the Bragg reflection law. In the multilayer reflective film 5, a plurality of high refractive index layers and a plurality of low refractive index layers are present, respectively, but the film thickness of the high refractive index layers from each other or the film thickness of the low refractive index layers from each other does not necessarily have to be the same. In addition, the film thickness of the Si layer on the surface of the multilayer reflective film 5 can be adjusted within a range that does not cause a decrease in reflectance. The film thickness of the Si (high refractive index layer) on the surface can be 3 nm to 10 nm.

[0106] The method of forming the multilayer reflective film 5 is known in the technical field, and each layer can be formed by, for example, an ion beam sputtering method. In the case of the Mo / Si periodic layer stack film described above, for example, by the ion beam sputtering method, first, a Si film having a thickness of about 4 nm is formed on the substrate 1 using a Si target, and then a Mo film having a thickness of about 3 nm is formed using a Mo target, which is taken as one period, and the multilayer reflective film 5 is formed by stacking 40 to 60 periods (the surface layer is made of a Si film). Note that in the case of 60 periods, the number of steps increases compared to 40 periods, but the reflectance for EUV light can be improved.

[0107] <<Protective Film 6>>

[0108] AsFigure 1 and Figure 2 As shown in FIG. 6, the multilayer reflective film-equipped substrate 110 of the present embodiment has a protective film 6 on the multilayer reflective film 5. By having the protective film 6 on the multilayer reflective film 5, damage to the surface of the multilayer reflective film 5 when the reflective mask 200 is manufactured using the multilayer reflective film-equipped substrate 110 can be suppressed. Thus, the reflectivity characteristics of the obtained reflective mask 200 to EUV light become good.

[0109] The protective film 6 of the present embodiment contains ruthenium (Ru) and an additive material. The additive material refers to at least one additive material selected from the group consisting of aluminum (Al), yttrium (Y), zirconium (Zr), rhodium (Rh), and hafnium (Hf). A thin film using Ru as the material is easily crystallized, has high crystallinity, and a thin film with high crystallinity is inferior in terms of density compared to an amorphous thin film. Thus, by having the protective film 6 contain the additive material, the density of the protective film 6 can be improved, and the resistance of the protective film 6 to etching gas and to cleaning can be improved. Note that the protective film 6 is a protective film 6 corresponding to the second layer 64 described later. As described later, the protective film 6 can further include the first layer 62 (see, for example, FIG. 8) in addition to the protective film 6 corresponding to the second layer 64. Figure 2 ).

[0110] The content of the additive material in the protective film 6 of the present embodiment is 5 atomic % or more and less than 50 atomic %. The content of the additive material is preferably 10 atomic % or more, and more preferably 20 atomic % or more. In addition, the content of the additive material is preferably 40 atomic % or less, and more preferably 35 atomic % or less. By adjusting the amount of the additive material, a protective film 6 that has high resistance to etching gas and SPM cleaning and does not greatly reduce the reflectivity of EUV can be formed. Thus, by having the content of the additive material in the protective film 6 be within the given range, the reduction in the reflectivity of EUV light of the multilayer reflective film 5 with the protective film 6 can be suppressed, and the resistance to etching gas and cleaning can be improved. In addition, in the case of an additive material having a higher extinction coefficient k than ruthenium (Ru), adjustment is preferably performed so that the extinction coefficient of the protective film 6 is 0.030 or less, and further preferably 0.025 or less.

[0111] The content of the additive material in the protective film 6 described above can be the content of the additive material in the second layer 64 described later. That is, the content of the additive material in the second layer 64 can be 5 atomic % or more and less than 50 atomic %. In addition, the content of the additive material is preferably 10 atomic % or more, and more preferably 20 atomic % or more. In addition, the content of the additive material is preferably 40 atomic % or less, and more preferably 35 atomic % or less.

[0112] Next, each case where the additive material contained in the protective film 6 is aluminum (Al), yttrium (Y), zirconium (Zr), rhodium (Rh), and hafnium (Hf) will be described. Note that the protective film 6 described below can be the second layer 64 described later.

[0113] As the material of the protective film 6 (or the second layer 64), in the case where aluminum (Al) is added to ruthenium (Ru) as an additive material (e.g., the case of a RuAl film), the etching resistance of the protective film 6 to a mixed gas of a chlorine-based gas and oxygen gas, the etching resistance to fluorine gas, and the sulfuric acid / hydrogen peroxide mixed solution (SPM) cleaning resistance of the protective film 6 are improved. When the Al concentration in the protective film 6 is too small, the effect of the addition cannot be obtained, and when the Al concentration is too large, the extinction coefficient of the protective film 6 to EUV light becomes high, and the reflectance of the reflective mask 200 decreases. In addition, when the Al concentration is too large, the resistance to fluorine gas decreases. Therefore, the Al concentration in the protective film 6 is preferably 5 atomic% or more and 40 atomic% or less, and more preferably 10 atomic% or more and 25 atomic% or less.

[0114] As the material of the protective film 6 (or the second layer 64), in the case where yttrium (Y) is added to ruthenium (Ru) as an additive material (e.g., the case of a RuY film), the etching resistance of the protective film 6 to a mixed gas of a chlorine-based gas and oxygen gas and the etching resistance to a fluorine-based gas become high. When the Y concentration in the protective film 6 is too small, the effect of the addition cannot be obtained, and when the Y concentration is too large, the sulfuric acid / hydrogen peroxide mixed solution (SPM) cleaning resistance of the protective film 6 decreases. Therefore, the Y concentration in the protective film 6 is preferably 5 atomic% or more and less than 50 atomic%, and more preferably 10 atomic% or more and 40 atomic% or less.

[0115] As the material of the protective film 6 (or the second layer 64), in the case where zirconium (Zr) is added to ruthenium (Ru) as an additive material (e.g., the case of a RuZr film), the etching resistance of the protective film 6 to a mixed gas of a chlorine-based gas and oxygen gas is improved. When the Zr concentration in the protective film 6 is too small, the effect of the addition cannot be obtained, and when the Zr concentration is too large, the sulfuric acid / hydrogen peroxide mixed solution (SPM) cleaning resistance of the protective film 6 decreases. In addition, when the Zr concentration is too large, the resistance to a chlorine-based gas decreases. Therefore, the Zr concentration in the protective film 6 is preferably 5 atomic% or more and 45 atomic% or less, and more preferably 10 atomic% or more and 25 atomic% or less.

[0116] As the material of the protective film 6 (or the second layer 64), in the case where rhodium (Rh) is added as an additive material to ruthenium (Ru) (for example, in the case of a RuRh film), the etching resistance of the protective film 6 against a mixed gas of a chlorine-based gas and oxygen, the etching resistance against a chlorine-based gas, the etching resistance against a fluorine-based gas, and the sulfuric acid / hydrogen peroxide mixed solution (SPM) cleaning resistance are improved. When the Rh concentration in the protective film 6 is too small, the effect of the addition cannot be obtained, and when the Rh concentration is too large, the extinction coefficient k of the protective film 6 against EUV light becomes high, and thus the reflectance of the reflective mask 200 decreases. Therefore, the Rh concentration in the protective film 6 is preferably 15 at.% or more and less than 50 at.%, and more preferably 20 at.% or more and 40 at.% or less.

[0117] Figure 5 The relationship between the content of Rh (at. %: horizontal axis) and the etching rate (nm / s: vertical axis) of the protective film using a mixed gas (Cl2+O2 gas) is shown in the case where Rh is added as an additive material to Ru. When the content of Rh is 20 at.% or more, the rate at which the etching rate decreases starts to decrease, and when the content of Rh is 30 at.% or more, the tendency becomes large, and when the content of Rh is 50 at.% or more, the etching rate hardly changes any more. From this, it is understood that the etching resistance of the protective film can be improved by increasing the content of Rh. Therefore, it is preferable to increase the content of Rh until the rate at which the etching rate decreases starts to decrease. However, since the etching rate hardly changes any more when the content of Rh exceeds 50 at.%, it is not necessary to set the content of Rh to be more than this value. Furthermore, when the content of Rh is large, the reflectance decreases, and when the content of Rh exceeds 50 at.%, the desired reflectance cannot be obtained, and thus the content of Rh is preferably less than 50 at.%. In this way, based on the obtained findings and taking into account the improvement in etching resistance and the decrease in reflectance due to the addition of Rh, a substrate with a multilayer reflective film that is excellent can be obtained.

[0118] In the case where the protective film 6 (or the second layer 64) contains ruthenium (Ru) and rhodium (Rh), the following conditions are preferable. In the present specification, the peak detected by X-ray diffraction refers to a peak when the measured data of the diffraction X-ray intensity with respect to the diffraction angle 2θ using Cu Kα rays is plotted, and those in which the height of the peak when the measured data (diffraction X-ray spectrum) is subtracted from the background is 2 times or more compared to the noise size (amplitude of the noise in the height direction) of the background near the peak can be selected. The diffraction angle 2θ of the peak can be set to the diffraction angle 2θ (the angle formed by the incident X-ray direction and the diffraction X-ray direction) of the display maximum value of the peak when the measured data is subtracted from the background.

[0119] Figure 6The results obtained by X-ray diffraction method using CuKα rays with respect to diffraction X-ray intensity (CPS) (vertical axis) against diffraction angle 2θ (horizontal axis) of a single film of ruthenium (Ru) (the direction of crystallization is shown in parentheses), a single film of rhodium (Rh), and RuRh films (formed at a ratio of Ru:Rh = 70:30, Ru:Rh = 50:50, and Ru:Rh = 30:70) are shown in FIG. 1. The single film of ruthenium (Ru) and the single film of rhodium (Rh) each show a high CPS against the diffraction angle 2θ, and thus, it is understood that the single film of ruthenium (Ru) and the single film of rhodium (Rh) have high crystallinity. The CPS against the diffraction angle 2θ of the RuRh films varies depending on the ratio of Ru and Rh, and the CPS against the diffraction angle 2θ is the lowest when Ru:Rh = 30:70. It is thus understood that, in the RuRh films, the more the content of Rh is, the lower the crystallinity is, and the higher the density is. However, when the content of Rh is large, the reflectance decreases, and when the content of Rh exceeds 50 at.%, it is not possible to obtain a desired reflectance, and thus, as described above, it is preferable that the content of Rh be less than 50 at.%.

[0120] In addition, as shown in FIG. 1, the diffraction angle is 42.0 degrees and the half-peak width is 0.62 when Ru:Rh = 70:30, the diffraction angle is 41.9 degrees and the half-peak width is 0.64 when Ru:Rh = 50:50, and the diffraction angle is 41.7 degrees and the half-peak width is 0.75 when Ru:Rh = 30:70. Figure 6

[0121] It is preferable that a peak be present in a range of 41.0 degrees or more and 43.0 degrees or less of the diffraction angle 2θ, and the half-peak width of the peak be 0.6 degrees or more. This is because the half-peak width of the single film of ruthenium (Ru (002)) is less than 0.6 degrees, and thus, when the half-peak width is less than 0.6 degrees, the crystallinity becomes high, and this is not preferable. When the half-peak width of the peak is less than 0.6 degrees, the crystallinity becomes high, and the density disappears, and thus, the etching resistance and the cleaning resistance become low.

[0122] In this way, it is possible to control the crystallinity depending on the range of the diffraction angle 2θ of the peak and the half-peak width of the peak. By controlling the crystallinity, it is possible to improve the resistance against a given etching gas and the cleaning resistance of the SPM or the like. The diffraction angle 2θ of the peak is preferably 41.0 degrees or more, and more preferably 41.3 degrees or more. In addition, the diffraction angle 2θ of the peak is preferably 43.0 degrees or less, and more preferably 42.0 degrees or less. The half-peak width of the peak is preferably 0.6 degrees or more, and more preferably 0.65 degrees or more. In addition, the half-peak width of the peak is preferably 0.8 degrees or less.

[0123] Figure 7 ​The results obtained by measuring the intensity of diffracted X-rays (CPS) with respect to the diffraction angle 2Θ by X-ray diffractometry using CuKα rays for three films to which nitrogen (N) was introduced (the amount of introduction of N was set to 3 sccm, 6 sccm, and 12 sccm, respectively) when the RuRh film (Ru:Rh = 70:30) was formed are shown in FIG. 6. As shown in FIG. 6, in the case where the amount of introduction of N was 3 sccm, the diffraction angle was 41.9 degrees and the half-value width was 0.68, in the case where the amount of introduction of N was 6 sccm, the diffraction angle was 41.8 degrees and the half-value width was 0.68, and in the case where the amount of introduction of N was 12 sccm, the diffraction angle was 41.6 degrees and the half-value width was 0.78. The same measurement results were obtained for the other films as well. Figure 7 The diffraction angle 2Θ of the peak of the RuRh film (Ru:Rh = 70:30) can be theoretically expected to be 41.8 degrees. It is known that by adding nitrogen, the denseness of the protective film can be improved, and the diffraction angle 2Θ of the peak of the protective film can be made close to this 41.8 degrees. By making the diffraction angle 2Θ of the peak of the protective film close to this 41.8 degrees, the residual stress in the protective film can be reduced. Figure 6

[0124] Thus, in the case where the protective film 6 (or the second layer 64) contains ruthenium (Ru) and rhodium (Rh), it is preferable that the protective film further contain nitrogen (N). By containing N, the crystallinity of the protective film can be reduced, and the denseness can be improved. In addition, by having nitrogen present at the interface between the protective film and the film on the protective film and / or the film under the protective film, and reducing the residual stress in the protective film, the adhesion of these can be improved, and the cleaning resistance can be improved. Furthermore, by improving the adhesion, the blister resistance (for example, the phenomenon in which the absorber film peels off from the surface of the protective film due to the absorption of hydrogen in the gaseous atmosphere during exposure is called "blistering") can also be improved.

[0125] As the material of the protective film 6 (or the second layer 64), in the case where hafnium (Hf) is added as an additive material to ruthenium (Ru) (for example, in the case of a RuHf film), the etching resistance of the protective film 6 with respect to a mixed gas of a chlorine-based gas and oxygen, and the sulfuric acid / hydrogen peroxide mixed solution (SPM) cleaning resistance are improved. When the Hf concentration in the protective film 6 is too small, the effect of the addition cannot be obtained, and when it is too large, the extinction coefficient k of the protective film 6 with respect to EUV light becomes high, and thus the reflectance of the reflective mask 200 decreases. Therefore, the Hf concentration in the protective film 6 is preferably 5 atomic% or more and 30 atomic% or less, and more preferably 10 atomic% or more and 25 atomic% or less.

[0126] As shown in FIG. 7, in the case where the amount of introduction of N was 3 sccm, the diffraction angle was 41.9 degrees and the half-value width was 0.68, in the case where the amount of introduction of N was 6 sccm, the diffraction angle was 41.8 degrees and the half-value width was 0.68, and in the case where the amount of introduction of N was 12 sccm, the diffraction angle was 41.6 degrees and the half-value width was 0.78. The same measurement results were obtained for the other films as well. Figure 2 ​As shown, the protective film 6 of the substrate 110 with the multilayer reflective film of the present embodiment preferably includes a first layer 62 and a second layer 64 from the substrate 1 side. Note that in the case where the protective film 6 includes the first layer 62 and the second layer 64, the second layer 64 can be made into the same film as the protective film 6 described above.

[0127] In the case where the multilayer reflective film 5 is a Mo / Si periodic layer stack film, since Mo is easily oxidized by the atmosphere, there is a risk that the reflectance of the multilayer reflective film 5 decreases. Therefore, the uppermost layer of the multilayer reflective film 5 is made into a Si layer. When the Si film is in contact with the protective film 6 made of Ru, silicon (Si) easily diffuses to the protective film 6. That is, with the passage of time, Si migrates and diffuses from the Si layer of the multilayer reflective film 5 toward the Ru-based protective film 6 between the grain boundaries of the Ru-based protective film 6 (then forming ruthenium silicide (RuSi)), and before reaching the surface layer of the Ru-based protective film 6, is subjected to an oxidation reaction due to cleaning liquid, gas, and generates SiO2. Further, in the case where the protective film 6 is not dense, the cleaning liquid, gas penetrates into the protective film 6, and SiO2is generated in the protective film 6 (inside or lower portion of the protective film 6). Also, since the adhesion of Ru to SiO2is low, there is a risk that the film peels off due to repeated cleaning in the manufacturing process of the reflective mask 200, or in use after completion in the form of a product. By making the protective film 6 have a given first layer 62, the diffusion of silicon (Si) from the multilayer reflective film 5 to the protective film 6 can be suppressed.

[0128] In order to suppress the diffusion of silicon (Si) from the multilayer reflective film 5 to the protective film 6, the first layer 62 preferably contains ruthenium (Ru), and contains at least one selected from the group consisting of magnesium (Mg), aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), germanium (Ge), zirconium (Zr), niobium (Nb), molybdenum (Mo), rhodium (Rh), hafnium (Hf), and tungsten (W). In particular, in the case where the first layer 62 is a RuTi film, a RuZr film, or a RuAl film, the diffusion of silicon (Si) to the protective film 6 can be more reliably suppressed.

[0129] The proportion of Ru in the Ru compound of the first layer 62 is preferably greater than 50 at.% and less than 100 at.%, further preferably 80 at.% or more and less than 100 at.%, particularly preferably greater than 95 at.% and less than 100 at.%.

[0130] In the case where the protective film 6 includes the first layer 62 and the second layer 64, the second layer 64 can be made of the same thin film as the protective film 6 described above. That is, the second layer 64 can contain ruthenium (Ru) and contain at least one additive material selected from the group consisting of aluminum (Al), yttrium (Y), zirconium (Zr), rhodium (Rh), and hafnium (Hf). Alternatively, the first layer 62 and the second layer 64 can be made of the same material with a changed composition ratio.

[0131] In the case where the first layer 62 is a RuTi-containing film (e.g., a RuTi film, a RuTiN film. The same applies to other RuY-containing films and the like), the second layer 64 is preferably a RuY-containing film, a RuZr-containing film, or a RuRh-containing film. In the case where the first layer 62 is a RuZr-containing film, the second layer 64 is preferably a RuAl-containing film, a RuY-containing film, a RuZr-containing film, or a RuRh-containing film. In this case, the diffusion of silicon (Si) into the protective film 6 can be more effectively suppressed by the first layer 62, and the resistance of the protective film 6 to etching gas and cleaning can be more effectively improved by the second layer 64.

[0132] The protective film 6 (the first layer 62 and / or the second layer 64) of the multilayer reflective film-equipped substrate 110 of the present embodiment can contain at least one selected from the group consisting of N, C, O, H, and B, within a range in which the effects of the present embodiment can be obtained. In order to reduce the crystallinity of the thin film and amorphize it, the protective film 6 (the first layer 62 and / or the second layer 64) preferably contains nitrogen (N) and / or oxygen (O).

[0133] The protective film 6 (the first layer 62 and / or the second layer 64) of the multilayer reflective film-equipped substrate 110 of the present embodiment preferably further contains nitrogen (N). By further containing nitrogen (N) in the protective film 6 (the first layer 62 and / or the second layer 64), the crystallinity can be reduced. As a result, the thin film can be made denser, and thus the resistance to etching gas and cleaning can be further improved. The proportion of N in the Ru compound of the protective film 6 (the first layer 62 and / or the second layer 64) is preferably greater than 1 at.% and 20 at.% or less, and further preferably 3 at.% or more and 10 at.% or less.

[0134] The protective film 6 (the first layer 62 and / or the second layer 64) of the multilayer reflective film-equipped substrate 110 of the present embodiment preferably further contains oxygen (O). By further containing oxygen (O) in the protective film 6 (the first layer 62 and / or the second layer 64), the crystallinity can be reduced. As a result, the thin film can be made denser, and thus the resistance to etching gas and cleaning can be further improved. The proportion of O in the Ru compound of the protective film 6 (the first layer 62 and / or the second layer 64) is preferably greater than 1 at.% and 20 at.% or less, and further preferably 3 at.% or more and 10 at.% or less.

[0135] In the multilayer reflective film-equipped substrate 110 of this embodiment, the Ru content of the second layer 64 is preferably less than the Ru content of the first layer 62. For example, in the case where the first layer 62 is a RuTi film and the second layer 64 is a RuRh film, even if the Ti content of the RuTi film of the first layer 62 is low, the diffusion of silicon (Si) into the protective film 6 can be suppressed. Therefore, by making the Ru content of the second layer 64 less than the Ru content of the first layer 62, the resistance to etching gas and cleaning can be further improved, and the diffusion of silicon (Si) into the protective film 6 can be suppressed.

[0136] In the multilayer reflective film-equipped substrate 110 of this embodiment, the refractive index of the second layer 64 is preferably less than the refractive index of the first layer 62. As a result, a protective film-equipped substrate (multilayer reflective film-equipped substrate 110 having a protective film 6) can be produced without reducing the reflectance of EUV light from the multilayer reflective film 5 including the protective film 6. The refractive index of the second layer 64 is preferably 0.920 or less, more preferably 0.885 or less.

[0137] The protective film 6 (the first layer 62 and / or the second layer 64) described above can be formed by various methods known in the art. As a method for forming the protective film 6, for example, ion beam sputtering, sputtering, reactive sputtering, chemical vapor deposition (CVD), and vacuum evaporation can be listed. In the case where the first layer 62 is formed by ion beam sputtering, the first layer 62 can be formed continuously after the formation of the multilayer reflective film 5, and is thus preferable. In the case where the protective film 6 (the first layer 62 and / or the second layer 64) contains nitrogen and / or oxygen, in order to perform stable film formation, it is preferable to use reactive sputtering.

[0138] In the case where the protective film 6 includes the first layer 62 and the second layer 64, heating treatment can be performed after the formation of the first layer 62 and the second layer 64, or after the formation of the absorber film 7. In this heating treatment, heating can be performed at a temperature higher than the pre-bake temperature (about 110°C) of the resist film 8 in the manufacturing process of the reflective mask blank 100. Specifically, the temperature conditions of the heating treatment are generally 160°C or higher and 300°C or lower, and are preferably set to 180°C or higher and 250°C or lower.

[0139] In the case where the above-described heating treatment process is performed, at least a part of the metal constituting the first layer 62 diffuses into the second layer 64, and further, a multilayer reflective film-equipped substrate 110 in which a composition gradient region in which the content of the metal component constituting the first layer 62 continuously decreases toward the second layer 64 is present between the first layer 62 and the second layer 64 can be obtained.

[0140] The film thickness of the protective film 6 (total of the first layer 62 and the second layer 64) is not particularly limited as long as the function as the protective film 6 is exerted. From the viewpoint of the reflectance of EUV light, the film thickness of the protective film 6 is preferably 1.0 nm to 8.0 nm, more preferably 1.5 nm to 6.0 nm. In addition, the film thickness of the first layer 62 is preferably 0.5 nm to 2.0 nm, more preferably 1.0 nm to 1.5 nm. In addition, the film thickness of the second layer 64 is preferably 1.0 nm to 7.0 nm, more preferably 1.5 nm to 4.0 nm.

[0141] <Reflection-type mask blank 100>

[0142] The reflection-type mask blank 100 according to the present embodiment is described. The reflection-type mask blank 100 has the absorber film 7 on the protective film 6 of the substrate 110 with the multilayer reflective film described above.

[0143] <Absorber film 7>

[0144] The absorber film 7 of the reflection-type mask blank 100 according to the present embodiment is formed on the multilayer reflective film 5 (on the protective film 6 in the case where the protective film 6 is formed). The basic function of the absorber film 7 is to absorb EUV light. The absorber film 7 can be an absorber film 7 for the purpose of absorbing EUV light, or can be an absorber film 7 having a phase shift function that also takes into account the phase difference of EUV light. The absorber film 7 having a phase shift function is an absorber film that absorbs EUV light and reflects a part of the light to shift the phase. That is, in the patterned reflection-type mask 200 in which the absorber film 7 having a phase shift function is formed, EUV light is absorbed in the portion where the absorber film 7 is formed to be attenuated, and a part of the light is reflected at a level that does not adversely affect the pattern transfer. In addition, in the region (field portion) where the absorber film 7 is not formed, EUV light is reflected from the multilayer reflective film 5 via the protective film 6. Thus, the reflected light from the absorber film 7 having a phase shift function and the reflected light from the field portion have a desired phase difference. The formation of the absorber film 7 having a phase shift function causes the phase difference between the reflected light from the absorber film 7 and the reflected light from the multilayer reflective film 5 to be 170 degrees to 190 degrees. The light having the phase difference of about 180 degrees interferes with each other at the pattern edge portion, thereby improving the image contrast of the projection optical image. With the improvement of the image contrast, the resolution increases, and various tolerances related to exposure, such as exposure amount tolerance and focus tolerance, can be increased.

[0145] The absorber film 7 can be a single layer film or a multi-layer film including a plurality of films (e.g., a lower absorber film and an upper absorber film). In the case of a single layer film, the number of processes can be reduced in the manufacture of the mask blank, thereby improving the production efficiency. In the case of a multi-layer film, the optical constants and the film thickness of the upper absorber film can be appropriately set so that the upper absorber film functions as an antireflection film in the inspection of the mask pattern defect using light. Thus, the inspection sensitivity in the inspection of the mask pattern defect using light can be improved. In addition, if a film to which oxygen (O) and nitrogen (N) or the like for improving oxidation resistance is added is used as the upper absorber film, the stability over time is improved. In this way, various functions can be added by making the absorber film 7 a multi-layer film. In the case where the absorber film 7 is an absorber film 7 having a phase shift function, the range of adjustment using the optical surface can be increased by making it a multi-layer film, and thus the desired reflectance can be obtained.

[0146] As the material of the absorber film 7, there is no particular limitation as long as it has a function of absorbing EUV light, can be processed by etching or the like (preferably, can be etched by dry etching using a chlorine (Cl)-based gas and / or a fluorine (F)-based gas), and has a high etching selectivity ratio with respect to the protective film 6 (the second layer 64). As the material having such a function, at least one metal selected from the group consisting of palladium (Pd), silver (Ag), platinum (Pt), gold (Au), iridium (Ir), tungsten (W), chromium (Cr), cobalt (Co), manganese (Mn), tin (Sn), tantalum (Ta), vanadium (V), nickel (Ni), hafnium (Hf), iron (Fe), copper (Cu), tellurium (Te), zinc (Zn), magnesium (Mg), germanium (Ge), aluminum (Al), rhodium (Rh), ruthenium (Ru), molybdenum (Mo), niobium (Nb), titanium (Ti), zirconium (Zr), yttrium (Y), and silicon (Si), or a compound thereof can be preferably used.

[0147] The absorber film 7 can be formed by a magnetron sputtering method such as a DC sputtering method and an RF sputtering method. For example, the absorber film 7 of a tantalum compound or the like can be formed by using a target containing tantalum and boron, and by a reactive sputtering method using argon gas to which oxygen or nitrogen is added.

[0148] The tantalum compound used for forming the absorber film 7 includes an alloy of Ta and the above-mentioned metal. In the case where the absorber film 7 is an alloy of Ta, the crystalline state of the absorber film 7 is preferably amorphous or microcrystalline from the aspects of smoothness and planarity. When the surface of the absorber film 7 is not smooth / flat, the edge roughness of the absorber pattern 7a can sometimes become large, and the dimensional accuracy of the pattern can deteriorate. The preferable surface roughness of the absorber film 7 is 0.5 nm or less, more preferably 0.4 nm or less, and further preferably 0.3 nm or less in terms of root mean square roughness (Rms).

[0149] As the tantalum compound used for forming the absorber film 7, a compound containing Ta and B, a compound containing Ta and N, a compound containing Ta, O, and N, a compound containing at least any one of O and N in addition to Ta and B, a compound containing Ta and Si, a compound containing Ta, Si, and N, a compound containing Ta and Ge, and a compound containing Ta, Ge, and N, etc. can be used.

[0150] Ta is a material having a large absorption coefficient for EUV light and can be easily dry-etched using a chlorine-based gas or a fluorine-based gas. Therefore, Ta can be said to be a material for the absorber film 7 having excellent processability. Further, by adding B, Si, and / or Ge, etc. to Ta, an amorphous material can be easily obtained. As a result, the smoothness of the absorber film 7 can be improved. In addition, if N and / or O is added to Ta, the resistance of the absorber film 7 to oxidation is improved, and therefore an effect of improving the stability over time can be obtained.

[0151] <<Back surface conductive film 2>>

[0152] On the second main surface (backside main surface) of the substrate 1 (on the opposite side of the surface on which the multilayer reflective film 5 is formed, on the intermediate layer in the case where an intermediate layer such as a hydrogen intrusion suppression film is formed on the substrate 1), a backside conductive film 2 for an electrostatic chuck can be formed. The sheet resistance required for the backside conductive film 2 for an electrostatic chuck is generally 100 Ω / square (Ω / square) or less. The method of forming the backside conductive film 2 is, for example, a magnetron sputtering method or an ion beam sputtering method using a target of a metal such as chromium or tantalum, or an alloy thereof. The material containing chromium (Cr) of the backside conductive film 2 is preferably a Cr compound containing at least one selected from boron, nitrogen, oxygen, and carbon in Cr. As the Cr compound, for example, CrN, CrON, CrCN, CrCON, CrBN, CrBON, CrBCN, and CrBOCN, etc. can be listed. As the material containing tantalum (Ta) of the backside conductive film 2, Ta (tantalum), an alloy containing Ta, or a Ta compound containing at least one of boron, nitrogen, oxygen, and carbon in any of them is preferably used. As the Ta compound, for example, TaB, TaN, TaO, TaON, TaCON, TaBN, TaBO, TaBON, TaBCON, TaHf, TaHfO, TaHfN, TaHfON, TaHfCON, TaSi, TaSiO, TaSiN, TaSiON, and TaSiCON, etc. can be listed. The film thickness of the backside conductive film 2 is not particularly limited as long as it can satisfy the function as an electrostatic chuck, and is generally 10 nm to 200 nm. In addition, the backside conductive film 2 also has a function of stress adjustment on the second main surface side of the reflective mask blank 100. That is, the backside conductive film 2 can be adjusted so that it balances with the stress from various films formed on the first main surface side, and thus a flat reflective mask blank 100 is obtained.

[0153] Note that the backside conductive film 2 can be formed on the multilayer reflective film-equipped substrate 110 before the above-described absorber film 7 is formed. The multilayer reflective film-equipped substrate 110 includes a case where the backside conductive film 2 is disposed on the second main surface of the multilayer reflective film-equipped substrate 110 as shown in FIGS. 1 to 3. Figure 1 and Figure 2 Note that the reflective mask blank 100 does not necessarily include the backside conductive film 2.

[0154] <etching mask film 9>

[0155] An etching mask film 9 can be formed on the absorber film 7. As a material of the etching mask film 9, a material having a high etching selectivity ratio of the absorber film 7 with respect to the etching mask film 9 is used. Here, the "etching selectivity ratio of B with respect to A" means a ratio of an etching rate of A which is a layer not intended to be etched (a layer to be a mask) to B which is a layer intended to be etched. Specifically, it can be specified by a mathematical expression of "etching selectivity ratio of B with respect to A = etching rate of B / etching rate of A". In addition, "high selectivity" means that the value of the selectivity defined above is large with respect to a comparison object. The etching selectivity ratio of the absorber film 7 with respect to the etching mask film 9 is preferably 1.5 or more, and further preferably 3 or more.

[0156] As a material having a high etching selectivity ratio of the absorber film 7 with respect to the etching mask film 9, a material of chromium and a chromium compound can be listed. In a case where the absorber film 7 is etched using a fluorine-based gas, a material of chromium and a chromium compound can be used. As the chromium compound, a material containing Cr, and at least one element selected from N, O, C, and H can be listed. In addition, in a case where the absorber film 7 is etched using a chlorine-based gas substantially not containing oxygen, a material of silicon and a silicon compound can be used. As the silicon compound, a material containing Si, and at least one element selected from N, O, C, and H, and a metal silicon (metal silicide) and a metal silicon compound (metal silicide compound) containing a metal in silicon and a silicon compound can be listed. As the metal silicon compound, a material containing a metal, Si, and at least one element selected from N, O, C, and H can be listed.

[0157] The reflective mask blank 100 of the present embodiment preferably contains the etching mask film 9 containing chromium (Cr) on the absorber film 7. The etching mask film 9 more preferably contains CrN, CrO, CrC, CrON, CrOC, CrCN, or CrOCN, and further preferably a CrO-based film (CrO film, CrON film, CrOC film, or CrOCN film) containing chromium and oxygen.

[0158] By providing the protective film 6 with the above-described configuration, damage to the protective film 6 at the time of peeling the etching mask film 9 containing chromium (Cr) by dry etching using a mixed gas of chlorine and oxygen can be suppressed.

[0159] Further, by making the protective film 6 (or the second layer 64) a RuAl-containing film, a RuY-containing film, or a RuRh-containing film, in the case where the etching mask film 9 is silicon or a silicon compound, damage to the protective film 6 at the time of peeling the etching mask film 9 by dry etching using a fluorine-based gas can be suppressed. Thus, the range of selection of the material of the absorber film 7 and / or the etching mask film 9 or the etching conditions is wide. Since damage to the protective film 6 by dry etching using a fluorine-based gas can be suppressed, the substrate 110 with a multilayer reflective film and the reflective mask blank 100 manufactured by the manufacturing method of the present embodiment can be provided with a resist film 8 in contact with the absorber film 7 without using the etching mask film 9. By drawing (exposing) a desired pattern such as a circuit pattern on the resist film 8 and further performing development and rinsing, a given resist pattern can be formed, and the absorber film 7 can be etched using the resist pattern as a mask to form an absorber pattern.

[0160] From the viewpoint of obtaining the function as an etching mask for forming a transfer pattern on the absorber film 7 with good precision, the film thickness of the etching mask film 9 is desirably 3 nm or more. Further, from the viewpoint of reducing the film thickness of the resist film 8, the film thickness of the etching mask film 9 is desirably 15 nm or less.

[0161] <Other Thin Films>

[0162] It is preferable that the substrate 110 with a multilayer reflective film and the reflective mask blank 100 of the present embodiment have a hydrogen intrusion suppression film between the glass substrate as the substrate 1 thereof and the back surface conductive film 2 containing tantalum or chromium, which suppresses intrusion of hydrogen from the substrate 1 into the back surface conductive film 2. Due to the presence of the hydrogen intrusion suppression film, hydrogen can be suppressed from being introduced into the back surface conductive film 2, and increase in compressive stress of the back surface conductive film 2 can be suppressed.

[0163] The material of the hydrogen intrusion suppression film can be any kind as long as hydrogen is not easily permeable therethrough and intrusion of hydrogen from the substrate 1 into the back surface conductive film 2 can be suppressed. As the material of the hydrogen intrusion suppression film, specific examples include, for example, Si, SiO2, SiON, SiCO, SiCON, SiBO, SiBON, Cr, CrN, CrON, CrC, CrCN, CrCO, CrCON, Mo, MoSi, MoSiN, MoSiO, MoSiCO, MoSiON, MoSiCON, TaO, and TaON. The hydrogen intrusion suppression film can be a single layer of these materials, and can also be a multilayer and a compositionally graded film.

[0164] <Reflective Mask 200>

[0165] The present embodiment is a reflective mask 200 in which the absorber film 7 in the above-described reflective mask blank 100 is patterned to have an absorber pattern 7a on the multilayer reflective film 5. By using the reflective mask blank 100 of the present embodiment, a reflective mask 200 having a protective film 6 that is high in resistance to etching gas and high in resistance to cleaning can be obtained.

[0166] A reflective mask 200 is manufactured using the reflective mask blank 100 of the present embodiment. Here, only a brief description is given, and a detailed description will be given later in the examples in conjunction with the drawings.

[0167] The reflective mask blank 100 is prepared, and a resist film 8 is formed on the outermost surface of the first main surface (on the etching mask film 9 formed on the absorber film 7 as described in the examples below) (not needed in the case where the resist film 8 is provided as the reflective mask blank 100), a desired pattern such as a circuit pattern is drawn (exposed) on the resist film 8, and further development and rinsing are performed, thereby forming a given resist pattern 8a.

[0168] The etching mask film 9 is dry-etched using the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a. Next, the absorber film 7 is dry-etched using the etching mask pattern 9a as a mask, thereby forming an absorber pattern 7a. Note that, as the etching gas for dry-etching the absorber film 7, a gas selected from among chlorine-based gases such as Cl2, SiCl4, and CHCl3, a mixed gas containing a chlorine-based gas and O2 at a given ratio, a mixed gas containing a chlorine-based gas and He at a given ratio, a mixed gas containing a chlorine-based gas and Ar at a given ratio, fluorine-based gases such as CF4, CHF3, C2F6, C3F6, C4F6, C4F8, CH2F2, CH3F, C3F8, SF6, and F2, and a mixed gas containing a fluorine-based gas and O2 at a given ratio, and the like can be used. Here, if oxygen is contained in the etching gas in the final stage of etching, surface roughness can occur in the Ru-based protective film 6. Therefore, in the over-etching stage in which the Ru-based protective film 6 is exposed to etching, an etching gas not containing oxygen is preferably used. After the absorber pattern 7a is formed, the etching mask pattern 9a can be removed using a mixed gas of a chlorine-based gas and oxygen or a fluorine-based gas.

[0169] Then, the resist pattern 8a is removed using ashing or a resist peeling solution, and an absorber pattern 7a in which a desired circuit pattern is formed is produced.

[0170] By the above procedures, the reflective mask 200 of the present embodiment can be obtained.

[0171] <Method for manufacturing semiconductor device>

[0172] The present embodiment relates to a method for manufacturing a semiconductor device, the method including a step of forming a transfer pattern on a transfer body by a photolithography process using the above-described reflective mask 200 and an exposure device. Specifically, the above-described reflective mask 200 can be disposed in an exposure device having an exposure light source that emits EUV light, and a resist film formed on a transfer substrate can be transferred with the transfer pattern. According to the method for manufacturing a semiconductor device of the present embodiment, since the reflective mask 200 that does not adversely affect the performance of the reflective mask 200 even if the thin film of the reflective mask 200 contains impurities (trace materials) can be used, a semiconductor device having a fine and high-precision transfer pattern can be manufactured.

[0173] Specifically, by performing EUV exposure using the above-described reflective mask 200 of the present embodiment, a desired transfer pattern can be formed on a semiconductor substrate. By performing various processes such as etching of a processed film, formation of an insulating film and a conductive film, introduction of a dopant, or annealing in addition to the photolithography process, a semiconductor device having a desired electronic circuit can be manufactured with a high yield.

[0174] Embodiments

[0175] Hereinafter, embodiments will be described. These embodiments do not limit the present application.

[0176] (Embodiments)

[0177] As an embodiment, a multilayer reflective film-equipped substrate 110 in which a multilayer reflective film 5 and a protective film 6 are formed on the first main surface of a substrate 1 was produced. The materials and compositions of the protective films 6 formed as an embodiment are shown in Table 1. The multilayer reflective film-equipped substrates 110 of each embodiment were produced similarly except that the types of the protective films 6 were different. As the protective film 6 of each embodiment, the protective films described below were used.

[0178] The protective film 6 of Embodiment 1-1 and Embodiment 1-2 was a RuAl film, and the protective film 6 of Embodiment 1-3 was a RuAlN film (see Figure 1 ). The protective film 6 of Embodiment 1-4 was a protective film 6 composed of a first layer 62 of a RuZr film and a second layer 64 of a RuAl film (see Figure 2 ).

[0179] The protective film 6 of Embodiment 2-1 and Embodiment 2-2 was a RuY film, and the protective film 6 of Embodiment 2-3 was a RuYN film (see Figure 1 ). The protective film 6 of Embodiment 2-4 was a protective film 6 composed of a first layer 62 of a RuTi film and a second layer 64 of a RuY film (see Figure 2 ).

[0180] The protective film 6 of Example 3-1 and Example 3-2 is a RuZr film, and the protective film 6 of Example 3-3 is a RuZrN film (see Figure 1 ). The protective film 6 of Example 3-4 is a protective film 6 composed of the first layer 62 of RuZr film and the second layer 64 of RuZr film (see Figure 2 ).

[0181] The protective film 6 of Example 4-1 and Example 4-2 is a RuRh film, and the protective film 6 of Example 4-3 is a RuRhN film (see Figure 1 ). The protective film 6 of Example 4-4 is a protective film 6 composed of the first layer 62 of RuTi film and the second layer 64 of RuRh film (see Figure 2 ).

[0182] The protective film 6 of Example 5-1 and Example 5-2 is a RuHf film, and the protective film 6 of Example 5-3 is a RuHfN film (see Figure 1 ). The protective film 6 of Example 5-4 is a protective film 6 composed of the first layer 62 of RuZr film and the second layer 64 of RuHf film (see Figure 2 ).

[0183] The production of the substrate 110 with a multilayer reflective film of the Examples was performed as described below.

[0184] A SiO2-TiO2-based glass substrate of 6025 size (about 152 mm x 152 mm x 6.35 mm) as a low thermal expansion glass substrate, whose both surfaces of the first main surface and the second main surface were polished, was prepared as a substrate 1. Polishing consisting of a rough polishing process, a precision polishing process, a local polishing process, and a touch polishing process was performed to obtain a flat and smooth main surface.

[0185] Next, the multilayer reflective film 5 was formed on the first main surface of the substrate 1. In order to make the multilayer reflective film 5 suitable for EUV light of wavelength 13.5 nm, it was made into a periodic multilayer reflective film 5 containing Si and Mo. Specifically, as a target of a high refractive index material and a target of a low refractive index material, a Si target and a Mo target were used. Kr ion particles were supplied to these targets from an ion source, and ion beam sputtering was performed, whereby Si layers and Mo layers were alternately laminated on the substrate 1.

[0186] Here, the sputtering particles of Si and Mo were made to be incident at an angle of 30 degrees with respect to the normal line of the first main surface of the substrate 1. First, a Si layer was formed with a film thickness of 4.2 nm, and then a Mo layer was formed with a film thickness of 2.8 nm. This was taken as one cycle, and similarly, 40 cycles were stacked, and finally a Si layer was formed with a film thickness of 4.0 nm, thereby forming the multilayer reflective film 5. Thus, the material of the lowermost layer of the multilayer reflective film 5, that is, the material of the multilayer reflective film 5 closest to the substrate 1 was Si, and the material of the uppermost layer of the multilayer reflective film 5, that is, the material of the multilayer reflective film 5 in contact with the protective film 6 was also Si.

[0187] Next, the protective film 6 shown in Table 1 was formed on the surface of the multilayer reflective film 5 by the ion beam sputtering method. For example, in the case of the protective film 6 of Example 1-1, a target for the ion beam sputtering method was a RuAl mixed sintered target having a composition shown in Table 1. In an Ar atmosphere, the protective film 6 of Example 1-1 composed of a RuAl film having a composition shown in Table 1 was formed by the ion beam sputtering method using the RuAl mixed sintered target with a film thickness shown in Table 1. Here, the sputtering particles of Ru and Al were made to be incident at an angle of 30 degrees with respect to the normal line of the first main surface of the substrate 1. The protective film 6 was formed similarly to Example 1-1 for the protective films 6 of the other examples.

[0188] Note that the protective films 6 of Example 1-3, Example 2-3, Example 3-3, Example 4-3, and Example 5-3 contain nitrogen (N). These protective films 6 were formed by reactive sputtering using a mixed gas atmosphere of Ar gas and N2 gas.

[0189] In addition, the protective films 6 of Example 1-4, Example 2-4, Example 3-4, Example 4-4, and Example 5-4 were protective films 6 composed of two layers of the first layer 62 and the second layer 64. Thus, in these examples, the second layer 64 was formed after the first layer 62 was formed. The composition and film thickness of the first layer 62 of these examples are shown in Table 2. In addition, the composition and film thickness of the second layer 64 of these examples are shown in Table 1.

[0190] The multilayer reflective film-equipped substrates 110 of the examples were manufactured as described above.

[0191] (Comparative Example 1)

[0192] The multilayer reflective film-equipped substrate 110 of Comparative Example 1 was manufactured similarly to Example 1-1 except that the protective film 6 was a single layer composed only of Ru. For the protective film 6 of Comparative Example 1, a film composed of Ru was formed with a film thickness shown in Table 1 by the ion beam sputtering method using a Ru target in an Ar atmosphere.

[0193] (Reflective mask blank 100)

[0194] Using the multilayer reflective film-equipped substrate 110 of the above-described embodiment and comparative example 1, a reflective mask blank 100 including an absorber film 7 and an etching mask film 9 was manufactured. Hereinafter, the manufacturing method of the reflective mask blank 100 will be described.

[0195] The absorber film 7 was formed on the protective film 6 of the multilayer reflective film-equipped substrate 110 by a DC magnetron sputtering method. The absorber film 7 was a laminated film absorber film 7 composed of a TaN film as an absorber layer and a TaO film as a low reflectance layer. The TaN film as an absorber layer was formed on the surface of the protective film 6 of the above-described multilayer reflective film-equipped substrate 110 by a DC magnetron sputtering method. The multilayer reflective film-equipped substrate 110 was opposed to a Ta target, and the TaN film was formed by a reactive sputtering method in an atmosphere of a mixed gas of Ar gas and N2 gas. Next, the TaO film (low reflectance layer) was further formed on the TaN film by a DC magnetron sputtering method. The TaO film was also formed by a reactive sputtering method in an atmosphere of a mixed gas of Ar and O2 by opposing the multilayer reflective film-equipped substrate 110 to the Ta target.

[0196] The composition (atomic ratio) of the TaN film was Ta:N = 70:30, and the film thickness was 48 nm. In addition, the composition (atomic ratio) of the TaO film was Ta:O = 35:65, and the film thickness was 11 nm.

[0197] Next, the etching mask film 9 composed of a CrOCN film was formed on the absorber film 7 by a DC magnetron sputtering method. The CrOCN film was formed by a reactive sputtering using a Cr target in an atmosphere of a mixed gas of Ar gas, N2 gas, and CO2 gas. The etching mask film 9 was formed to a film thickness of 5 nm.

[0198] Next, the back surface conductive film 2 containing CrN was formed on the second main surface (back side main surface) of the substrate 1 by a magnetron sputtering method (reactive sputtering method) under the following conditions. Formation conditions of the back surface conductive film 2: Cr target, mixed gas atmosphere of Ar and N2 (Ar: 90 atomic%, N: 10 atomic%), film thickness 20 nm.

[0199] The reflective mask blank 100 of the embodiment and comparative example 1 was manufactured as described above.

[0200] (Reflective mask 200)

[0201] Next, the reflective mask 200 was manufactured using the reflective mask blank 100 of the embodiment and comparative example 1. The manufacturing method of the reflective mask 200 will be described with reference to Figure 8 The manufacturing of the reflective mask 200 will be described.

[0202] Figure 8 (a) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. First, as shown in (b), a resist film 8 is formed on an etching mask film 9 of the reflective mask blank 100. Then, a desired pattern such as a circuit pattern is drawn (exposed) on the resist film 8, and further development, rinsing are performed, thereby forming a given resist pattern 8a (c). Figure 4 Figure 8 (b) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. First, as shown in (b), a resist film 8 is formed on an etching mask film 9 of the reflective mask blank 100. Then, a desired pattern such as a circuit pattern is drawn (exposed) on the resist film 8, and further development, rinsing are performed, thereby forming a given resist pattern 8a (c). Figure 8 (c)) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. Next, using a Cl2gas and an O2gas mixed gas (Cl2+ O2gas) as an etching gas, dry etching is performed on the etching mask film 9 with the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a (d). Figure 8 (d)) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. Next, using a Cl2gas and an O2gas mixed gas (Cl2+ O2gas) as an etching gas, dry etching is performed on the etching mask film 9 with the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a (d). Figure 8 (e)) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. Next, using a Cl2gas and an O2gas mixed gas (Cl2+ O2gas) as an etching gas, dry etching is performed on the etching mask film 9 with the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a (d).

[0203] (f)) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. Next, using a Cl2gas and an O2gas mixed gas (Cl2+ O2gas) as an etching gas, dry etching is performed on the etching mask film 9 with the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a (d). Figure 8 (f)) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. Next, using a Cl2gas and an O2gas mixed gas (Cl2+ O2gas) as an etching gas, dry etching is performed on the etching mask film 9 with the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a (d).

[0204] (f)) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. Next, using a Cl2gas and an O2gas mixed gas (Cl2+ O2gas) as an etching gas, dry etching is performed on the etching mask film 9 with the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a (d).

[0205] (f)) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. Next, using a Cl2gas and an O2gas mixed gas (Cl2+ O2gas) as an etching gas, dry etching is performed on the etching mask film 9 with the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a (d).

[0206] (f)) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. Next, using a Cl2gas and an O2gas mixed gas (Cl2+ O2gas) as an etching gas, dry etching is performed on the etching mask film 9 with the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a (d).

[0207] (f)) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. Next, using a Cl2gas and an O2gas mixed gas (Cl2+ O2gas) as an etching gas, dry etching is performed on the etching mask film 9 with the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a (d). Figure 4 (f)) is a cross-sectional schematic view of an example reflective mask blank 100 described in this specification. Next, using a Cl2gas and an O2gas mixed gas (Cl2+ O2gas) as an etching gas, dry etching is performed on the etching mask film 9 with the resist pattern 8a as a mask, thereby forming an etching mask pattern 9a (d). Figure 8 ​(e) An etch mask pattern 9a and an absorber pattern 7a of the same type. The absorber pattern 7a used for evaluation was shaped to allow for the measurement of EUV light reflectance on the exposed portion of the protective film 6, resulting in a pattern that significantly exposes the surface of the protective film 6. After forming the absorber pattern 7a, the reflectance of the protective film 6 surface to EUV light at a wavelength of 13.5 nm (reflectance before etching) was measured. Next, the etch mask pattern 9a of the CrOCN film was removed using dry etching with a mixture of Cl2 and O2 gases (Cl2:O2 = 9:1). Figure 8 (f)). After removing the etched mask pattern 9a by etching, the reflectance of the surface of the protective film 6 to EUV light with a wavelength of 13.5 nm was measured (reflectance after etching). Column A of Table 3 shows the change in reflectance before and after the etched mask pattern 9a was removed by etching (reflectance after etching / reflectance before etching). The change in reflectance is expressed as a ratio when Comparative Example 1 is set to 1.

[0208] Furthermore, the change in film thickness of the protective film 6 during dry etching using the aforementioned mixed gas of Cl2 and O2 (Cl2+O2 gas) was measured, and the etching rates of each material were calculated as a ratio when the etching rate of the Ru film of the protective film 6 using the mixed gas was set to 1. Column B of Table 3 shows the etching rate ratios of the protective film 6 using the mixed gas.

[0209] As can be clearly seen from Table 3, compared to Comparative Example 1, the change in reflectivity of the etched mask pattern 9a before and after etching is small in all embodiments. Furthermore, compared to Comparative Example 1, the etching rate of the protective film 6 using the mixed gas (Cl2 + O2 gas) is low in all embodiments. Therefore, it is clear that the protective film 6 of this embodiment has high resistance to the etching gas used to remove the etched mask film 9.

[0210] In addition, the resistance of the protective film 6 to cleaning with a sulfuric acid / hydrogen peroxide mixed solution (SPM) was separately measured. The results clearly show that, compared with Comparative Example 1, the film thickness change before and after cleaning was small in all examples, and the change in reflectivity to EUV light was small. Therefore, the protective film 6 has high resistance to cleaning.

[0211] Table 4 shows the rate of decrease in film thickness when SPM cleaning was performed under the following cleaning conditions, with Comparative Example 1 (Ru film) set to 1.

[0212] The cleaning solution is composed of H₂SO₄ and H₂O₂ in a weight ratio of 2:1.

[0213] Cleaning temperature 120℃

[0214] Cleaning time: 10 minutes

[0215] As is clear from Table 4, the SPM cleaning resistance of Example 4-2 (Ru:Rh = 70:30) and Example 4-3 (Ru:Rh:N = 65:30:5) is higher than that of Example 4-1 (Ru:Rh = 80:20). Note that the protective film of Example 4-4 is the same as that of Example 4-2, and thus the rate of decrease in the film thickness of Comparative Example 1 (Ru film) when set to 1 is the same as that of Example 4-2.

[0216] (MANUFACTURE OF SEMICONDUCTOR DEVICE)

[0217] The reflective mask 200 manufactured using the multilayer reflective film-equipped substrate 110 of the example was set to an EUV scanner, and a wafer on which a processed film and a resist film were formed was subjected to EUV exposure. Then, the exposed resist film was developed, whereby a resist pattern was formed on the semiconductor substrate on which the processed film was formed.

[0218] The reflective mask 200 manufactured using the multilayer reflective film-equipped substrate 110 of the example has a protective film with high resistance to etching gas and high resistance to cleaning, and thus a fine and high-precision transfer pattern (resist pattern) can be formed.

[0219] The resist pattern is transferred to the processed film by etching, and in addition, various processes such as formation of an insulating film and a conductive film, introduction of a dopant, or annealing are performed, whereby a high yield of semiconductor devices with desired characteristics can be achieved.

[0220] [Table 1]

[0221]

[0222] [Table 2]

[0223]

[0224] [Table 3]

[0225]

[0226] [Table 4]

[0227]

Claims

1. A substrate with a multilayer reflective film, comprising: a substrate, a multilayer reflective film provided on the substrate, and a protective film provided on the multilayer reflective film, wherein the protective film contains ruthenium (Ru) and contains at least one additive material selected from the group consisting of aluminum (Al), rhodium (Rh), and hafnium (Hf), the content of the aluminum (Al) is 5 atomic% or more and 40 atomic% or less, the content of the rhodium (Rh) is 15 atomic% or more and less than 50 atomic%, and the content of the hafnium (Hf) is 5 atomic% or more and 30 atomic% or less.

2. The substrate with a multilayer reflective film according to claim 1, wherein the protective film comprises a first layer and a second layer from the substrate side, the first layer contains ruthenium (Ru) and contains at least one selected from the group consisting of magnesium (Mg), aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), germanium (Ge), zirconium (Zr), niobium (Nb), molybdenum (Mo), rhodium (Rh), hafnium (Hf), and tungsten (W), and the second layer contains the ruthenium (Ru) and contains at least one additive material selected from the group consisting of aluminum (Al), rhodium (Rh), and hafnium (Hf).

3. The substrate with a multilayer reflective film according to claim 1, wherein the protective film further contains nitrogen (N) at a content of more than 1 atomic% and 20 atomic% or less.

4. The substrate with a multilayer reflective film according to claim 1, wherein the protective film has an extinction coefficient of 0.030 or less. wherein 5. The substrate with a multilayer reflective film according to claim 2, wherein the first layer or the second layer further contains nitrogen (N) at a content of more than 1 atomic% and 20 atomic% or less.

6. The substrate with a multilayer reflective film according to claim 2, wherein the second layer has a Ru content less than that of the first layer.

7. The substrate with a multilayer reflective film according to claim 2, wherein the second layer has a refractive index less than that of the first layer.

8. A reflective mask blank having an absorber film on the protective film of the substrate with a multilayer reflective film according to any one of claims 1 to 7.

9. The reflective mask blank according to claim 8, comprising an etching mask film on the absorber film, the etching mask film containing chromium (Cr).

10. A reflective mask comprising an absorber pattern obtained by patterning the absorber film in the reflective mask blank according to claim 8.

11. A method of manufacturing a reflective mask, the method comprising: patterning the etching mask film of the reflective mask blank according to claim 9 to form an etching mask pattern; patterning the absorber film using the etching mask pattern as a mask to form an absorber pattern; and removing the etching mask pattern using a mixed gas of a chlorine-based gas and oxygen.

12. A method of manufacturing a semiconductor device, the method comprising: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The reflective mask according to claim 10 is arranged in an exposure apparatus having an exposure light source which emits EUV light, and an antireflection film formed on a substrate to be transferred is transferred with a transfer pattern.

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