Reflection type mask blank, reflection type mask, method for manufacturing reflection type mask blank, and method for manufacturing reflection type mask

Abstract

To provide a technique which suppresses crystallization of a phase shift film, and improves hydrogen resistance of the phase shift film.SOLUTION: A reflection type mask blank has a substrate, a multilayer reflection film for reflecting EUV light, a protective film for protecting the multilayer reflection film, and a phase shift film for shifting the phase of the EUV light, in this order. The phase shift film contains at least one first element X1 selected from a first group consisting of Ru, Ir, Pt, Pd and Au, and at least one second element X2 selected from a second group consisting of oxygen (O), boron (B), carbon (C) and nitrogen (N). The phase shift film has a chemical shift of a peak of 3d5 / 2 or 4f7 / 2 of the first element X1, which is observed by X-ray electron spectroscopy, of less than 0.3 eV.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a reflective mask blank, a reflective mask, a method for manufacturing a reflective mask blank, and a method for manufacturing a reflective mask. [Background technology]

[0002] In recent years, with the miniaturization of semiconductor devices, EUV lithography (EUVL), an exposure technology using extreme ultraviolet (EUV) light, has been developed. EUV includes soft X-rays and vacuum ultraviolet light, and specifically refers to light with a wavelength of about 0.2 nm to 100 nm. At present, EUV with a wavelength of about 13.5 nm is mainly being considered.

[0003] In EUVL, a reflective mask is used. The reflective mask has, in that order, a substrate such as a glass substrate, a multilayer reflective film that reflects EUV light, and a phase shift film that shifts the phase of the EUV light. An opening pattern is formed in the phase shift film. In EUVL, the opening pattern in the phase shift film is transferred to a target substrate such as a semiconductor substrate. Transferring includes reducing and transferring.

[0004] In EUVL, a so-called projection effect (shadowing effect) occurs. The shadowing effect is a phenomenon in which the sidewalls of the opening pattern block the EUV light in an area near the sidewalls, due to the incident angle θ of the EUV light being not 0° (for example, 6°), causing a positional or dimensional shift in the transferred image. In order to reduce the shadowing effect, it is effective to lower the height of the sidewalls of the opening pattern, and to make the phase shift film thinner.

[0005] Ruthenium (Ru) has been considered as a material for the phase shift film in order to make it thinner. Ruthenium has a low refractive index, so it is possible to make the phase shift film thinner while maintaining the phase difference. However, when ruthenium is used alone, it has the problem that it is prone to crystallization. The larger the crystal size, the greater the roughness of the side walls of the opening pattern. This is because etching tends to proceed along the crystal grain boundaries when the opening pattern is formed.

[0006] The phase shift film of Patent Document 1 contains at least ruthenium, nitrogen, and oxygen. Patent Document 1 describes that by adding nitrogen and oxygen to ruthenium, the crystallites (i.e., the size of the crystals) can be made smaller, and the roughness of the sidewalls of the opening pattern can be reduced. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent No. 6929983 Summary of the Invention [Problem to be solved by the invention]

[0008] Inside the EUV exposure tool, the reflective mask may be exposed to hydrogen gas, which is used, for example, to reduce carbon contamination.

[0009] Conventionally, when a phase shift film is exposed to hydrogen gas, nonmetallic elements contained in the phase shift film may be released.

[0010] One aspect of the present disclosure provides a technique for suppressing crystallization of a phase shift film and improving the hydrogen resistance of the phase shift film. [Means for solving the problem]

[0011] A reflective mask blank according to one embodiment of the present disclosure includes, in this order, a substrate, a multilayer reflective film that reflects EUV light, a protective film that protects the multilayer reflective film, and a phase shift film that shifts the phase of the EUV light. The phase shift film includes at least one first element X1 selected from a first group consisting of Ru, Ir, Pt, Pd, and Au, and at least one second element X2 selected from a second group consisting of O, B, C, and N. The phase shift film has a 3d 5 / 2 Or 4f 7 / 2 The chemical shift of the peak is less than 0.3 eV. Effect of the Invention

[0012] According to one embodiment of the present disclosure, the phase shift film is formed of the first element X1 and the second element X2, thereby suppressing crystallization of the phase shift film. In addition, the chemical shift of the first element X1 is less than 0.3 eV, thereby suppressing desorption of the second element X2, thereby improving the hydrogen resistance of the phase shift film. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view showing a reflective mask blank according to one embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a reflective mask according to an embodiment. [Diagram 3] FIG. 3 is a cross-sectional view showing an example of EUV light reflected by the reflective mask of FIG. [Figure 4] FIG. 4 is a diagram showing an example of the refractive index and extinction coefficient of an element or compound. [Diagram 5] FIG. 5 is a graph showing the chemical shift of Ru contained in the phase shift film of Example 1. [Figure 6] FIG. 6 is a graph showing the chemical shift of Ta contained in the phase shift film of Example 1. [Figure 7] FIG. 7 is a diagram showing an X-ray diffraction spectrum of the phase shift film of Example 1. [Figure 8]FIG. 8 is a flowchart showing a method for manufacturing a reflective mask blank according to one embodiment. [Figure 9] FIG. 9 is a flowchart showing a method for manufacturing a reflective mask according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and the description may be omitted. In the specification, the symbol "~" indicating a range of values ​​means that the values ​​before and after the symbol are included as the lower and upper limits.

[0015] 1 to 3, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The Z-axis direction is perpendicular to the first main surface 10a of the substrate 10. The X-axis direction is perpendicular to the incidence surface of the EUV light (the surface including the incident light beam and the reflected light beam). As shown in FIG. 3, the incident light beam is inclined toward the positive Y-axis direction as it moves toward the negative Z-axis direction, and the reflected light beam is inclined toward the positive Y-axis direction as it moves toward the positive Z-axis direction.

[0016] A reflective mask blank 1 according to one embodiment will be described with reference to Fig. 1. The reflective mask blank 1 has, for example, a substrate 10, a multilayer reflective film 11, a protective film 12, a phase shift film 13, and an etching mask film 14, in this order. The multilayer reflective film 11, the protective film 12, the phase shift film 13, and the etching mask film 14 are formed, in this order, on a first main surface 10a of the substrate 10. It should be noted that the reflective mask blank 1 only needs to have at least the substrate 10, the multilayer reflective film 11, the protective film 12, and the phase shift film 13.

[0017] The reflective mask blank 1 may further have a functional film not shown in FIG. 1. For example, the reflective mask blank 1 may have a conductive film on the opposite side of the multilayer reflective film 11 with respect to the substrate 10. The conductive film is formed on the second main surface 10b of the substrate 10. The second main surface 10b is the surface facing opposite to the first main surface 10a. The conductive film is used, for example, to attach the reflective mask 2 to an electrostatic chuck of an exposure tool. The reflective mask blank 1 may have a diffusion barrier film (not shown) between the multilayer reflective film 11 and the protective film 12. The diffusion barrier film suppresses diffusion of metal elements contained in the protective film 12 into the multilayer reflective film 11.

[0018] Although not shown, the reflective mask blank 1 may have a buffer film between the protective film 12 and the phase shift film 13. The buffer film protects the protective film 12 from an etching gas that forms an opening pattern 13a in the phase shift film 13. The buffer film is etched more slowly than the phase shift film 13. Unlike the protective film 12, the buffer film will ultimately have the same opening pattern as the opening pattern 13a of the phase shift film 13.

[0019] Next, a reflective mask 2 according to one embodiment will be described with reference to Figures 2 and 3. The reflective mask 2 is produced, for example, by using the reflective mask blank 1 shown in Figure 1, and includes an opening pattern 13a in a phase shift film 13. Note that the etching mask film 14 shown in Figure 1 is removed after the opening pattern 13a is formed in the phase shift film 13.

[0020] In EUVL, the opening pattern 13a of the phase shift film 13 is transferred to a target substrate such as a semiconductor substrate. The transfer includes reducing and transferring. The substrate 10, the multilayer reflective film 11, the protective film 12, the phase shift film 13, and the etching mask film 14 will be described below in this order.

[0021] The substrate 10 is, for example, a glass substrate. The material of the substrate 10 is preferably quartz glass containing TiO2. Quartz glass has a smaller linear expansion coefficient and a smaller dimensional change due to temperature change than general soda-lime glass. Quartz glass may contain 80% to 95% by mass of SiO2 and 4% to 17% by mass of TiO2. When the TiO2 content is 4% to 17% by mass, the linear expansion coefficient is approximately zero near room temperature, and there is almost no dimensional change near room temperature. Quartz glass may contain a third component or impurity other than SiO2 and TiO2. The material of the substrate 10 may be crystallized glass in which a β-quartz solid solution is precipitated, silicon, metal, or the like.

[0022] The substrate 10 has a first main surface 10a and a second main surface 10b facing opposite to the first main surface 10a. A multilayer reflective film 11 and the like are formed on the first main surface 10a. The size of the substrate 10 in plan view (viewed in the Z-axis direction) is, for example, 152 mm long and 152 mm wide. The vertical and horizontal dimensions may be 152 mm or more. The first main surface 10a and the second main surface 10b each have, for example, a square quality assurance area in the center. The size of the quality assurance area is, for example, 142 mm long and 142 mm wide. The quality assurance area of ​​the first main surface 10a preferably has a root-mean-square roughness (Rq) of 0.15 nm or less and a flatness of 100 nm or less. In addition, it is preferable that the quality assurance area of ​​the first main surface 10a does not have a defect that causes a phase defect.

[0023] The multilayer reflective film 11 reflects EUV light. The multilayer reflective film 11 is, for example, a film in which high refractive index layers and low refractive index layers are alternately laminated. The high refractive index layers are made of, for example, silicon (Si), and the low refractive index layers are made of, for example, molybdenum (Mo), and a Mo / Si multilayer reflective film is used. Note that the multilayer reflective film 11 can also be made of a Ru / Si multilayer reflective film, a Mo / Be multilayer reflective film, a Mo compound / Si compound multilayer reflective film, a Si / Mo / Ru multilayer reflective film, a Si / Mo / Ru / Mo multilayer reflective film, a Si / Ru / Mo / Ru multilayer reflective film, or a Si / Ru / Mo / Ru multilayer reflective film.

[0024] The film thickness of each layer constituting the multilayer reflective film 11 and the number of repeating units of the layer can be appropriately selected according to the material of each layer and the reflectivity with respect to EUV light. When the multilayer reflective film 11 is a Mo / Si multilayer reflective film, in order to achieve a reflectivity of 60% or more with respect to EUV light having an incident angle θ (see Fig. 3) of 6°, a Mo layer with a film thickness of 2.3 ± 0.1 nm and a Si layer with a film thickness of 4.5 ± 0.1 nm may be laminated so that the number of repeating units is 30 or more and 60 or less. The multilayer reflective film 11 preferably has a reflectivity of 60% or more with respect to EUV light having an incident angle θ of 6°. More preferably, the reflectivity is 65% or more.

[0025] The film formation method of each layer constituting the multilayer reflective film 11 is, for example, a DC sputtering method, a magnetron sputtering method, or an ion beam sputtering method. When forming a Mo / Si multilayer reflective film using the ion beam sputtering method, an example of the film formation conditions for each of the Mo layer and the Si layer is as follows. <Film formation conditions for Si layer> Target: Si target, Sputtering gas: Ar gas, Gas pressure: 1.3×10 -2 Pa~2.7×10 -2 Pa, Ion acceleration voltage: 300 V~1500 V, Film formation rate: 0.030 nm / sec~0.300 nm / sec, Film thickness of Si layer: 4.5 ± 0.1 nm, <Film formation conditions for Mo layer> Target: Mo target, Sputtering gas: Ar gas, Gas pressure: 1.3×10 -2 Pa~2.7×10 -2 Pa, Ion acceleration voltage: 300 V~1500 V, Film formation rate: 0.030 nm / sec~0.300 nm / sec, Film thickness of Mo layer: 2.3 ± 0.1 nm, <Repeating unit of Si layer and Mo layer> Number of repeating units: 30~60 (preferably 40~50).

[0026] The protective film 12 is formed between the multilayer reflective film 11 and the phase shift film 13 to protect the multilayer reflective film 11. The protective film 12 protects the multilayer reflective film 11 from an etching gas that forms an opening pattern 13a (see FIG. 2) in the phase shift film 13. The etching gas is, for example, a halogen-based gas, an oxygen-based gas, or a mixed gas thereof. Examples of the halogen-based gas include a chlorine-based gas and a fluorine-based gas. Examples of the chlorine-based gas are Cl2 gas, SiCl4 gas, CHCl3 gas, CCl4 gas, BCl3 gas, or a mixed gas thereof. Examples of the fluorine-based gas are CF4 gas, CHF3 gas, SF6 gas, BF3 gas, XeF2 gas, or a mixed gas thereof. Examples of the oxygen-based gas are O2 gas, O3 gas, or a mixed gas thereof.

[0027] The ratio (ER1 / ER2) of the etching rate ER1 of the phase shift film 13 by the etching gas to the etching rate ER2 of the protective film 12 by the etching gas is also called the first selectivity. The larger the first selectivity, the better the processability of the phase shift film 13. The first selectivity is preferably 10 or more, and more preferably 30 or more. The first selectivity is preferably 200 or less, and more preferably 100 or less.

[0028] The protective film 12 contains at least one element selected from, for example, Ru, Rh, and Si. When the protective film 12 contains Rh, the protective film 12 may contain only Rh, or may contain, in addition to Rh, at least one element Z1 selected from the group consisting of Ru, Nb, Mo, Ta, Ir, Pd, Zr, Y, and Ti.

[0029] When element Z1 is Ru, Nb, Mo, Zr, Y, or Ti, the extinction coefficient k can be reduced while suppressing an increase in the refractive index n, and the reflectance to EUV light can be improved. When element Z1 is Ru, Ta, Ir, Pd, or Y, the durability to etching gas and / or sulfuric acid / hydrogen peroxide can be improved. Sulfuric acid / hydrogen peroxide is used for removing a resist film described later, or for cleaning a reflective mask 2.

[0030] The element ratio (Z1:Rh) of Z1 (all Z1) to Rh is preferably 1:99 to 1:1. In this specification, the element ratio means a molar ratio. If the ratio value (Z1 / Rh) is 1 / 99 or more, the reflectance to EUV light is good. If the ratio value (Z1 / Rh) is 1 or less, the durability of the protective film 12 to the etching gas is good. The element ratio (Z1:Rh) of Z1 to Rh is more preferably 3:10 to 1:1.

[0031] The protective film 12 may contain, in addition to Rh, at least one element Z2 selected from the group consisting of N, O, C, and B. The element Z2 reduces the durability of the protective film 12 against etching gas, but improves the smoothness of the protective film 12 by reducing the crystallinity of the protective film 12. The protective film 12 containing the element Z2 has an amorphous structure or a microcrystalline structure. When the protective film 12 has an amorphous structure or a microcrystalline structure, the X-ray diffraction profile of the protective film 12 does not have a clear peak.

[0032] When the protective film 12 contains Z2 in addition to Rh, the content of Rh or the total content of Rh and Z1 is preferably 40 at% to 99 at% and the total content of Z2 is 1 at% to 60 at%. When the protective film 12 contains Z2 in addition to Rh, the content of Rh or the total content of Rh and Z1 is more preferably 80 at% to 99 at% and the total content of Z2 is 1 at% to 20 at%.

[0033] The protective film 12 contains 90 at % or more of Rh, contains at least one of Z1 and Z2, and has a density of 10.0 g / cm 3 ~14.0g / cm 3 When the protective film 12 has a film density of 11.0 g / cm3, the protective film 12 has an amorphous structure or a microcrystalline structure. 3 ~13.0g / cm 3 The protective film 12 contains 100 at % Rh and has a density of 11.0 g / cm 3 ~12.0g / cm 3 When the protective film 12 has a film density of 0.1 to 100%, the protective film 12 has an amorphous structure or a microcrystalline structure. The film density of the protective film 12 is measured by X-ray reflectance method.

[0034] The film thickness of the protective film 12 is preferably 1.0 nm or more and 10.0 nm or less, more preferably 2.0 nm or more and 3.5 nm or less.

[0035] The root mean square roughness (Rq) of the protective film 12 is preferably 0.3 nm or less, more preferably 0.1 nm or less.

[0036] The method for forming the protective film 12 is, for example, a DC sputtering method, a magnetron sputtering method, or an ion beam sputtering method. When forming a Rh film using the DC sputtering method, an example of the film formation conditions is as follows. <Film formation conditions of Rh film> Target: Rh target, Sputtering gas: Ar gas, Gas pressure: 1.0×10 -2 Pa~1.0×10 0 Pa, Output density of target: 1.0 W / cm 2 ~8.5 W / cm 2 、 Film formation rate: 0.020 nm / sec~1.000 nm / sec, Film thickness of Rh film: 1 nm~10 nm.

[0037] When forming a Rh film, as the sputtering gas, N2 gas or a mixed gas of Ar gas and N2 may be used. The volume ratio of N2 gas in the sputtering gas (N2 / (Ar + N2)) is 0.05 or more and 1.0 or less.

[0038] When forming a RhO film using the DC sputtering method, an example of the film formation conditions is as follows. <Film formation conditions of RhO film> Target: Rh target, Sputtering gas: O2 gas or a mixed gas of Ar gas and O2, Volume ratio of O2 gas in the sputtering gas (O2 / (Ar + O2)): 0.05~1.0, Gas pressure: 1.0×10 -2 Pa~1.0×100 Pa Output density of target: 1.0 W / cm 2 ~8.5 W / cm 2 , Film formation rate: 0.020 nm / sec to 1.000 nm / sec, Film thickness of RhO film: 1 nm to 10 nm.

[0039] When forming a RhRu film using the DC sputtering method, an example of the film formation conditions is as follows. <Film formation conditions of RhRu film> Target: Rh target and Ru target (or RhRu target), Sputtering gas: Ar gas, Gas pressure: 1.0×10 -2 Pa to 1.0×10 0 Pa, Output density of target: 1.0 W / cm 2 ~8.5 W / cm 2 , Film formation rate: 0.020 nm / sec to 1.000 nm / sec, Film thickness of RhRu film: 1 nm to 10 nm.

[0040] The phase shift film 13 is a film on which the aperture pattern 13a is to be formed. The aperture pattern 13a is not formed in the manufacturing process of the reflective mask blank 1, but is formed in the manufacturing process of the reflective mask 2. The phase shift film 13 shifts the phase of the second EUV light L2 with respect to the first EUV light L1 shown in FIG. 3.

[0041] The first EUV light L1 passes through the aperture pattern 13a without passing through the phase shift film 13, is reflected by the multilayer reflective film 11, and then passes through the aperture pattern 13a again without passing through the phase shift film 13. The second EUV light L2 passes through the phase shift film 13 while being absorbed by the phase shift film 13, is reflected by the multilayer reflective film 11, and then passes through the phase shift film 13 again while being absorbed by the phase shift film 13.

[0042] The phase difference (≧0) between the first EUV light L1 and the second EUV light L2 is, for example, 170° to 250°. The phase of the first EUV light L1 may be ahead of or behind the phase of the second EUV light L2. The phase shift film 13 improves the contrast of the transferred image by utilizing the interference between the first EUV light L1 and the second EUV light L2. The transferred image is an image obtained by transferring the opening pattern 13a of the phase shift film 13 onto the target substrate.

[0043] In EUVL, a so-called projection effect (shadowing effect) occurs. The shadowing effect refers to a region in which the sidewall of the opening pattern 13a blocks the EUV light due to the incident angle θ of the EUV light being not 0° (for example, 6°), resulting in a positional or dimensional shift of the transferred image. In order to reduce the shadowing effect, it is effective to reduce the height of the sidewall of the opening pattern 13a, and it is also effective to thin the phase shift film 13.

[0044] The thickness of the phase shift film 13 is, for example, 60 nm or less, and preferably 50 nm or less, in order to reduce the shadowing effect. The thickness of the phase shift film 13 is preferably 20 nm or more, and more preferably 30 nm or more, in order to ensure a phase difference between the first EUV light L1 and the second EUV light L2.

[0045] In order to reduce the thickness of the phase shift film 13 so as to reduce the shadowing effect while ensuring the phase difference between the first EUV light L1 and the second EUV light L2, it is effective to reduce the refractive index of the phase shift film 13.

[0046] The phase shift film 13 includes at least one first element X1 selected from a first group consisting of Ru, Ir, Pt, Pd, and Au. The first element X1 is a precious metal element. As is clear from FIG. 4, the first element X1 has a small refractive index, so that the phase shift film 13 can be thinned while maintaining the phase difference. A phase shift film lower layer may be further provided between the phase shift film 13 and the protective film 12. The phase shift film lower layer is a layer formed in contact with the uppermost surface of the protective film 12. The two-layer structure of the phase shift film 13 and the phase shift film lower layer allows the phase difference between the first EUV light L1 and the second EUV light L2 to be adjusted. From the viewpoint of processing characteristics, it is preferable that the phase shift film lower layer mainly contains Ta and the phase shift film 13 contains Ru.

[0047] However, when the first element X1 is used alone, there is a problem that it is easily crystallized. The larger the crystal size, the rougher the sidewall of the opening pattern 13a becomes. This is because etching tends to proceed along the crystal grain boundaries when the opening pattern 13a is formed.

[0048] The phase shift film 13 contains at least one second element X2 selected from a second group consisting of O, B, C, and N, in addition to the first element X1. The second element X2 is a nonmetallic element. By adding the second element X2 to the first element X1, crystallization of the phase shift film 13 can be suppressed, and roughness of the sidewall of the opening pattern 13a can be reduced. The second element X2 preferably contains oxygen, and more preferably contains oxygen and nitrogen. The phase shift film 13 preferably contains at least one second element X2 selected from a second group consisting of O, B, and C, in addition to the first element X1. The phase shift film 13 more preferably contains O in an amount of 1 at% or more and less than 55 at%.

[0049] The phase shift film 13 is a 3d phase shift film of the first element X1 observed by X-ray photoelectron spectroscopy (XPS). 5 / 2 Or 4f 7 / 2 The chemical shift ΔE1 of the peak is less than 0.3 eV. 5 / 2 Or 4f 7 / 2The peaks are the 3d peaks of Ru or Pd. 5 / 2 or the 4f peak of Ir, Pt or Au 7 / 2 This is the peak.

[0050] The binding energy of electrons observed by X-ray photoelectron spectroscopy represents the amount of energy consumed when an electron is ejected. When the first element X1 is bonded to a nonmetallic element, the first element X1 becomes positively charged, so a large amount of energy is consumed for the electron to shake off the first element X1 and be ejected. Therefore, when the first element X1 is bonded to a nonmetallic element, the peak binding energy becomes higher than when the first element X1 exists alone.

[0051] The chemical shift ΔE1 of the peak of the first element X1 observed by X-ray electron spectroscopy is the magnitude (absolute value) of the difference between the binding energy of the peak of the first element X1 actually observed and the binding energy of the peak of the first element X1 when it is not bound to a nonmetallic element and exists alone (reference binding energy). The binding energy of the peak of the first element X1 actually observed is basically higher than the reference binding energy. The reference binding energy of each element is the literature value described in HANDBOOK OF X-RAY PHOTOELECTRON SPECTROSCOPY (1979), (authors: D. Wagner, WM Riggs, LE Davis, JF Maulder, GE Muilenberg), etc.

[0052] If the chemical shift ΔE1 of the peak of the first element X1 observed by X-ray photoelectron spectroscopy is less than 0.3 eV, the first element X1 and the second element X2 contained in the phase shift film 13 are hardly bonded. If the first element X1 and the second element X2 are not bonded, the bond is not broken by hydrogen gas, and a hydride of the second element X2 is not generated. If a hydride of the second element X2 is generated, the second element X2 is desorbed from the phase shift film 13 because the hydride is highly volatile. The chemical shift ΔE1 is preferably less than 0.3 eV, more preferably 0.2 eV or less, and even more preferably 0.1 eV or less.

[0053] The chemical shift ΔE1 of the peak of the first element X1 can be adjusted by, for example, multi-target sputtering using a target containing the first element X1, a target containing the second element X2, and a target containing the third element X3, or reactive sputtering using a target containing the first element X1 and a target containing the third element X3. The third element X3 contained in the phase shift film 13 selectively bonds with the second element X2 by multi-target sputtering or reactive sputtering, thereby suppressing the bond between the first element X1 and the second element X2, and also suppressing the bond from being broken by hydrogen gas, thereby suppressing the generation of hydride of the second element X2. Therefore, the chemical shift ΔE1 of the peak of the first element X1 can be adjusted to less than 0.3 eV. The method of supplying the second element X2 is not particularly limited, but it is preferable to supply it from a gas or a target, and more preferable to supply it as a gas. As the gas, oxygen, nitrogen, or methane is preferably used. When the element X2 is supplied as a gas, in multi-target sputtering using a target containing the element X1 and a target containing the element X3, it is preferable to supply the gas of the element X2 from near the target containing the element X3. By doing so, the chemical shift ΔE3 of the peak of the third element X3 can be made larger than the chemical shift ΔE1 of the peak of the first element X1.

[0054] The chemical shift ΔE1 of the peak of the first element X1 can also be adjusted by multi-sputtering of a target containing the first element X1 and a compound target containing the second element X2 and the third element X3. By using a compound target containing the second element X2 and the third element X3, the bond between the first element X1 and the second element X2 is suppressed, and the bond is also suppressed from being broken by hydrogen gas, so that the generation of hydride of the second element X2 can be suppressed. Therefore, the chemical shift ΔE1 of the peak of the first element X1 can be adjusted to less than 0.3 eV.

[0055] Conventionally, when the phase shift film 13 contains Ru as the first element X1 and O as the second element X2, that is, when the phase shift film 13 is a RuO film, Ru and O are bonded. The bond between Ru and O is broken by hydrogen gas, and H2O is generated. As a result, the RuO film is sometimes reduced to a Ru film. When the RuO film is reduced to a Ru film, the film thickness after reduction is smaller than the film thickness before reduction, and the phase difference between the first EUV light L1 and the second EUV light L2 cannot be ensured.

[0056] In the present invention, the analysis of the phase shift film by XPS is carried out as follows. For the analysis by XPS, an analyzer "PHI 5000 VersaProbe" manufactured by ULVAC-PHI, Inc. is used. The above-mentioned apparatus is calibrated in accordance with JIS K0145. First, a measurement sample of about 1 cm square is cut out from a reflective mask blank, and the measurement sample is set in a measurement holder so that the phase shift film becomes the measurement surface. After the measurement holder is loaded into the above-mentioned apparatus, a portion of the phase shift film is removed with an argon ion beam until the peak observed from the outermost surface becomes constant. After removing the surface of the phase shift film, the removed area is irradiated with X-rays (monochromated AlKα rays) and analyzed with a photoelectron take-off angle (the angle between the surface of the measurement sample and the direction of the detector) of 45°. During the analysis, a neutralizing gun is used to suppress charge-up. The analysis involves a wide scan in the binding energy range of 0eV to 1000eV to confirm the elements present, followed by a narrow scan depending on the elements present. Narrow scans are performed with, for example, a pass energy of 58.7eV, an energy step of 0.1eV, a time / step of 50ms, and five accumulations. Wide scans are performed with a pass energy of 58.7eV, an energy step of 1eV, a time / step of 50ms, and two accumulations. Here, the bond energy is calibrated using the peak of the C1s orbital derived from carbon present on the measurement sample. Specifically, first, the bond energy value indicating the peak of the C1s orbital in the measurement sample is obtained from the narrow scan analysis result, and the value obtained by subtracting this bond energy value from 284.8 eV is used as the shift value. The above shift value is added to the bond energy value indicating the peak of each orbital obtained from the narrow scan analysis result, and the bond energy value of the peak corresponding to each orbital defined above is calculated. The bond energy may be calibrated using Au whose surface has been cleaned in ultra-high vacuum. In this case, the shift value is calculated by subtracting Au4f 7 / 2 The binding energy value of the orbital is obtained from the narrow scan analysis results and is calculated by subtracting the binding energy value from 83.96 eV. When reading the binding energy value indicating the peak of each orbital from the narrow scan analysis results, the value indicating the peak top is read as the binding energy value.

[0057] According to this embodiment, the first element X1 and the second element X2 contained in the phase shift film 13 are hardly bonded to each other, and the bond is not broken by hydrogen gas. Therefore, a hydride of the second element X2 is not generated, and the second element X2 is not desorbed from the phase shift film 13. Therefore, the hydrogen resistance of the phase shift film 13 can be improved, and the change in the film thickness of the phase shift film 13 can be suppressed.

[0058] The phase shift film 13 preferably contains a third element X3, at least one of an oxide, a boride, a carbide, and a nitride, whose standard Gibbs energy of formation is -130 kJ / mol or less. In other words, the phase shift film 13 preferably contains a compound of X1, X2, and X3. The standard Gibbs energy of formation is the free energy required to synthesize a substance from a certain element, based on a state in which the element is stable as a single element under standard conditions (25°C, 1 atm). The lower the standard Gibbs energy of formation, the more stable the substance.

[0059] If the standard Gibbs energy of formation of the oxide, boride, carbide or nitride, which is a compound of the third element X3 and the second element X2, is -130 kJ / mol or less, the stability of the compound is sufficiently high, the third element X3 and the second element X2 are strongly bonded, and the bond is not broken by hydrogen gas. Therefore, the generation of the hydride of the second element X2 can be suppressed, and the second element X2 can be suppressed from being detached from the phase shift film 13. Therefore, the hydrogen resistance of the phase shift film 13 can be improved. The above-mentioned standard Gibbs energy of formation is more preferably -500 kJ / mol or less.

[0060] The third element X3 is, for example, at least one selected from a third group consisting of Ta, Nb, Mo, Cr, Si, Hf, W, and Re. The third group element has the standard Gibbs energy of formation of −500 kJ / mol or less.

[0061] Among the elements in the third group, Ta, Nb, and Si tend to improve the resistance of phase shift film 13 to SPM. SPM is used for removing resist films, which will be described later, or for cleaning reflective masks 2. On the other hand, among the elements in the third group, Mo, Cr, Hf, W, and Re have a large first selectivity and provide good processability for phase shift film 13.

[0062] In the phase shift film 13, the chemical shift ΔE3 of the peak of the third element X3 observed by X-ray photoelectron spectroscopy is 0.2 eV or more. The peak of the third element X3 is, for example, the 4f peak of Ta, Hf, W or Re. 7 / 2 or Nb or Mo 3d 5 / 2 or the Si 2p peak 3 / 2 peak or Cr 2p 3 / 2 This is the peak.

[0063] The binding energy of electrons observed by X-ray photoelectron spectroscopy represents the amount of energy consumed when an electron is ejected. When the third element X3 is bonded to a nonmetallic element, the third element X3 becomes positively charged, so a large amount of energy is consumed for the electron to shake off the third element X3 and be ejected. Therefore, when the third element X3 is bonded to a nonmetallic element, the peak binding energy becomes higher than when the third element X3 exists alone.

[0064] The chemical shift ΔE3 of the peak of the third element X3 observed by X-ray photoelectron spectroscopy is the magnitude (absolute value) of the difference between the binding energy of the peak of the third element X3 actually observed and the binding energy of the peak of the third element X3 when it is not bound to a nonmetallic element and exists alone (reference binding energy). The binding energy of the peak of the third element X3 actually observed is basically higher than the reference binding energy.

[0065] The chemical shift ΔE3 of the peak of the third element X3 is preferably larger than the chemical shift ΔE1 of the peak of the first element X1. The third element X3 is bonded stronger to the second element X2 than to the first element X1 (the bond between X3 and X2 is stronger than the bond between X1 and X2), and the bond (the bond between X3 and X2) is not broken by hydrogen gas. Therefore, the generation of hydride of the second element X2 can be suppressed, and the second element X2 can be suppressed from being desorbed from the phase shift film 13. Therefore, the hydrogen resistance of the phase shift film 13 can be improved.

[0066] The chemical shift ΔE3 of the peak of the third element X3 observed by X-ray photoelectron spectroscopy is preferably 0.2 eV or more, more preferably 0.3 eV or more, even more preferably 0.5 eV or more, still more preferably 1.0 eV or more, particularly preferably 2.0 eV or more, and more particularly preferably 2.5 eV or more.

[0067] The phase shift film 13 is not particularly limited, but may contain, for example, a first element X1 of 40 at% to 98 at% in total, a second element X2 of 1 at% to 59 at% in total, and a third element X3 of 1 at% to 30 at% in total. When the contents of the first element X1, the second element X2, and the third element X3 are within the above ranges, crystallization of the phase shift film 13 is suppressed, and the hydrogen resistance of the phase shift film 13 is effectively improved.

[0068] The total content of the first element X1 is, for example, 40 at% to 98 at%. If the total content of the first element X1 is 40 at% or more, the refractive index of the phase shift film 13 is low, and the shadowing effect can be reduced while ensuring the phase difference between the first EUV light L1 and the second EUV light L2. The total content of the first element X1 is preferably 60 at% to 98 at%, and more preferably 80 at% to 98 at%.

[0069] The total content of the second element X2 is, for example, 1 at% to 59 at%. If the total content of the second element X2 is 1 at% or more, crystallization of the phase shift film 13 can be suppressed and roughness of the sidewall of the opening pattern 13a can be reduced. If the total content of the second element X2 is 59 at% or less, the hydrogen resistance of the phase shift film 13 can be improved. The total content of the second element X2 is preferably 1 at% to 59 at%, more preferably 1 at% to 30 at%, further preferably 1 at% to 20 at%, and particularly preferably 1 at% to 15 at%.

[0070] The total content of the third element X3 is, for example, 1 at% to 30 at%. If the total content of the third element X3 is 1 at% or more, the hydrogen resistance of the phase shift film 13 can be improved. If the total content of the third element X3 is 30 at% or less, the first selectivity is large and the processability of the phase shift film 13 is good. The total content of the third element X3 is preferably 1 at% to 20 at%, and more preferably 2 at% to 15 at%.

[0071] The ratio (X1 / X3) of the total content (at%) of the first element X1 to the total content (at%) of the third element X3 is, for example, 6 to 97. If the ratio (X1 / X3) of the total content of the first element X1 to the total content (at%) of the third element X3 is 6 or more, the hydrogen resistance of the phase shift film 13 can be improved. If the ratio (X1 / X3) of the total content of the first element X1 to the total content of the third element X3 is 97 or less, the first selectivity is large and the processability of the phase shift film 13 is good. The ratio (X1 / X3) of the total content of the first element X1 to the total content of the third element X3 is preferably 6 to 96, more preferably 7 to 96, further preferably 7 to 95, and particularly preferably 7 to 60.

[0072] When the first element X1 is Ru and the third element X3 is Ta, the ratio (Ru / Ta) of the Ru content (at%) to the Ta content (at%) is, for example, 10 to 97. If the ratio (Ru / Ta) of the Ru content to the Ta content is 10 or more, the hydrogen resistance of the phase shift film 13 can be improved. If the ratio (Ru / Ta) of the Ru content to the Ta content is 97 or less, the first selectivity is large and the processability of the phase shift film 13 is good. The ratio (Ru / Ta) of the Ru content to the Ta content is preferably 10 to 97, more preferably 15 to 96, further preferably 18 to 95.5, and particularly preferably 20 to 50.

[0073] When the first element X1 is Ru and the third element X3 is Cr, the ratio (Ru / Cr) of the Ru content (at%) to the Cr content (at%) is, for example, 1 to 13. When the ratio (Ru / Cr) of the Ru content to the Cr content is 1 or more, the hydrogen resistance of the phase shift film 13 can be improved. When the ratio (Ru / Cr) of the Ru content to the Cr content is 13 or less, the first selectivity is large and the processability of the phase shift film 13 is good. The ratio (Ru / Cr) of the Ru content to the Cr content is preferably 1 to 13, more preferably 1 to 6, further preferably 1.5 to 5.7, and particularly preferably 1.8 to 5.6.

[0074] When the first element X1 is Ru and the third element X3 is Mo, the ratio (Ru / Mo) of the Ru content (at%) to the Mo content (at%) is, for example, 1 to 20. When the ratio (Ru / Mo) of the Ru content to the Mo content is 1 or more, the hydrogen resistance of the phase shift film 13 can be improved. When the ratio (Ru / Mo) of the Ru content to the Mo content is 20 or less, the first selectivity is large and the processability of the phase shift film 13 is good. The ratio (Ru / Mo) of the Ru content to the Mo content is preferably 1 to 20, more preferably 2 to 18, further preferably 4 to 10, and particularly preferably 5 to 8.

[0075] When the first element X1 is Ru and the third element X3 is W, the ratio (Ru / W) of the Ru content (at%) to the W content (at%) is, for example, 1 to 20. When the ratio (Ru / W) of the Ru content to the W content is 1 or more, the hydrogen resistance of the phase shift film 13 can be improved. When the ratio (Ru / W) of the Ru content to the W content is 20 or less, the first selectivity is large and the processability of the phase shift film 13 is good. The ratio (Ru / W) of the Ru content to the W content is preferably 1 to 20, more preferably 2 to 18, further preferably 2 to 15, and particularly preferably 2 to 9.

[0076] When the first element X1 is Ru and the third element X3 is Hf, the ratio (Ru / Hf) of the Ru content (at%) to the Hf content (at%) is, for example, 1 to 45. If the ratio (Ru / Hf) of the Ru content to the Hf content is 1 or more, the hydrogen resistance of the phase shift film 13 can be improved. If the ratio (Ru / Hf) of the Ru content to the Hf content is 45 or less, the first selectivity is large and the processability of the phase shift film 13 is good. The ratio (Ru / Hf) of the Ru content to the Hf content is preferably 1 to 45, more preferably 2 to 40, further preferably 2 to 10, and particularly preferably 3 to 6.

[0077] When the first element X1 is Ir and the third element X3 is Ta, the ratio (Ir / Ta) of the Ir content (at%) to the Ta content (at%) is, for example, 1 to 40. When the ratio (Ir / Ta) of the Ir content to the Ta content is 1 or more, the hydrogen resistance of the phase shift film 13 can be improved. When the ratio (Ir / Ta) of the Ir content to the Ta content is 40 or less, the first selectivity is large and the processability of the phase shift film 13 is good. The ratio (Ir / Ta) of the Ir content to the Ta content is preferably 1 to 40, more preferably 1 to 35, further preferably 2 to 25, particularly preferably 2 to 10, and most preferably 2 to 6.

[0078] When the first element X1 is Ir and the third element X3 is Cr, the ratio (Ir / Cr) of the Ir content (at%) to the Cr content (at%) is, for example, 1 to 10. When the ratio (Ir / Cr) of the Ir content to the Cr content is 1 or more, the hydrogen resistance of the phase shift film 13 can be improved. When the ratio (Ir / Cr) of the Ir content to the Cr content is 10 or less, the first selectivity is large and the processability of the phase shift film 13 is good. The ratio (Ir / Cr) of the Ir content to the Cr content is preferably 1 to 10, more preferably 2 to 8, and further preferably 3 to 6.

[0079] When the first element X1 is Pt and the third element X3 is Ta, the ratio (Pt / Ta) of the Pt content (at%) to the Ta content (at%) is, for example, 40 to 90. If the ratio (Pt / Ta) of the Pt content to the Ta content is 40 or more, the hydrogen resistance of the phase shift film 13 can be improved. If the ratio (Pt / Ta) of the Pt content to the Ta content is 90 or less, the first selectivity is large and the processability of the phase shift film 13 is good. The ratio (Pt / Ta) of the Pt content to the Ta content is preferably 40 to 90, more preferably 45 to 88, further preferably 50 to 85, and particularly preferably 60 to 82.

[0080] When the first element X1 is Ru and the second element X2 is O, the ratio (Ru / O) of the Ru content (at%) to the O content (at%) is, for example, more than 0.7 to 50. When the ratio (Ru / O) of the Ru content to the O content is more than 0.7, crystallization of the phase shift film 13 can be suppressed and roughness of the sidewall of the opening pattern 13a can be reduced. When the ratio (Ru / O) of the Ru content to the O content is 50 or less, the hydrogen resistance of the phase shift film 13 can be improved. The ratio (Ru / O) of the Ru content to the O content is preferably more than 0.7 to 50, more preferably 0.8 to 40, further preferably 1 to 35, particularly preferably 2 to 30, and most preferably 3 to 25.

[0081] When the first element X1 is Ru and the second element X2 is N, the ratio (Ru / N) of the Ru content (at%) to the N content (at%) is, for example, 11 to 50. When the ratio (Ru / N) of the Ru content to the N content is 11 or more, crystallization of the phase shift film 13 can be suppressed and roughness of the sidewall of the opening pattern 13a can be reduced. When the ratio (Ru / N) of the Ru content to the N content is 50 or less, the hydrogen resistance of the phase shift film 13 can be improved. The ratio (Ru / N) of the Ru content to the N content is preferably 11 to 50, more preferably 11.5 to 45, further preferably 12 to 44, particularly preferably 20 to 43, and most preferably 25 to 42.

[0082] When the first element X1 is Ir and the second element X2 is O, the ratio (Ir / O) of the Ir content (at%) to the O content (at%) is, for example, 1 to 40. When the ratio (Ir / O) of the Ir content to the O content is 1 or more, crystallization of the phase shift film 13 can be suppressed and roughness of the sidewall of the opening pattern 13a can be reduced. When the ratio (Ir / O) of the Ir content to the O content is 40 or less, the hydrogen resistance of the phase shift film 13 can be improved. The ratio (Ir / O) of the Ir content to the O content is preferably 1 to 40, more preferably 2 to 35, further preferably 2 to 30, particularly preferably 2 to 20, and most preferably 3 to 15.

[0083] When the first element X1 is Ir and the second element X2 is N, the ratio (Ir / N) of the Ir content (at%) to the N content (at%) is, for example, 10 to 50. When the ratio (Ir / N) of the Ir content to the N content is 10 or more, crystallization of the phase shift film 13 can be suppressed and roughness of the sidewall of the opening pattern 13a can be reduced. When the ratio (Ir / N) of the Ir content to the N content is 50 or less, the hydrogen resistance of the phase shift film 13 can be improved. The ratio (Ir / N) of the Ir content to the N content is preferably 10 to 50, more preferably 10 to 45, further preferably 10 to 40, particularly preferably 11 to 35, and most preferably 12 to 30.

[0084] When the first element X1 is Pt and the second element X2 is O, the ratio (Pt / O) of the Pt content (at%) to the O content (at%) is, for example, 0.5 to 10. When the ratio (Pt / O) of the Pt content to the O content is 0.5 or more, crystallization of the phase shift film 13 can be suppressed and roughness of the sidewall of the opening pattern 13a can be reduced. When the ratio (Pt / O) of the Pt content to the O content is 10 or less, the hydrogen resistance of the phase shift film 13 can be improved. The ratio (Pt / O) of the Pt content to the O content is preferably 0.5 to 10, more preferably 0.7 to 8, and further preferably 1 to 5.

[0085] When the first element X1 is Ru and the second element X2 is O and N, the ratio (Ru / (O+N)) of the Ru content (at%) to the total of the O content (at%) and the N content (at%) is, for example, more than 0.8 to 30. If the ratio (Ru / (O+N)) of the Ru content to the total of the O content and the N content is more than 0.8, the crystallization of the phase shift film 13 can be suppressed and the roughness of the sidewall of the opening pattern 13a can be reduced. If the ratio (Ru / (O+N)) of the Ru content to the total of the O content and the N content is 30 or less, the hydrogen resistance of the phase shift film 13 can be improved. The ratio (Ru / (O+N)) of the Ru content to the total of the O content and the N content is preferably more than 0.8 to 30, more preferably more than 0.8 to less than 11.3, more preferably 1 to 11, even more preferably 2 to 10.5, particularly preferably 2 to 10, and most preferably 2.2 to 8.

[0086] When the first element X1 is Ir and the second element X2 is O and N, the ratio (Ir / (O+N)) of the Ru content (at%) to the total of the O content (at%) and the N content (at%) is, for example, 1 to 25. When the ratio (Ir / (O+N)) of the Ru content to the total of the O content and the N content is 1 or more, the crystallization of the phase shift film 13 can be suppressed and the roughness of the sidewall of the opening pattern 13a can be reduced. When the ratio (Ir / (O+N)) of the Ru content to the total of the O content and the N content is 25 or less, the hydrogen resistance of the phase shift film 13 can be improved. The ratio (Ir / (O+N)) of the Ru content to the total of the O content and the N content is preferably 1 to 25, more preferably 2 to 20, further preferably 2.5 to 17, particularly preferably 4 to 16, and most preferably 6 to 12.

[0087] The phase shift film 13 has a full width at half maximum FWHM of 1.0° or more of the highest intensity peak in the 2θ range of 20° to 50° measured by XRD using CuKα radiation. The out of plane method is used as the XRD method. If the full width at half maximum FWHM is 1.0° or more, the crystallinity of the phase shift film 13 is low, and the roughness of the sidewall of the opening pattern 13a can be reduced. The full width at half maximum FWHM is preferably 2.0° or more, more preferably 3.0° or more, and particularly preferably 4.0° or more. The larger the full width at half maximum FWHM, the better, and it is preferable that there is no clear peak.

[0088] The refractive index n of the phase shift film 13 is, for example, 0.930 or less, preferably 0.920 or less, more preferably 0.915 or less, even more preferably 0.910 or less, and particularly preferably 0.900 or less. The refractive index n is preferably 0.885 or more. In this specification, the refractive index is the refractive index for light with a wavelength of 13.5 nm.

[0089] The extinction coefficient k of the phase shift film 13 is, for example, 0.015 or more, preferably 0.020 or more, more preferably 0.025 or more, even more preferably 0.030 or more, particularly preferably 0.035 or more, and most preferably 0.040 or more. The extinction coefficient k is preferably 0.065 or less. In this specification, the extinction coefficient is the extinction coefficient for light with a wavelength of 13.5 nm.

[0090] The optical properties (refractive index n and extinction coefficient k) of the phase shift film 13 are taken from the database of the Center for X-Ray Optics, Lawrence Berkeley National Laboratory, or values ​​calculated from the "incident angle dependence" of reflectance described below.

[0091] The incident angle θ of the EUV light, the reflectance R for the EUV light, the refractive index n of the phase shift film 13, and the extinction coefficient k of the phase shift film 13 satisfy the following formula (1). R = |(sinθ-((n+ik) 2 -cos2 θ) 1 / 2 ) / (sinθ+((n+ik) 2 -cos 2 θ) 1 / 2 )|···(1) A number of combinations of the incident angle θ and the reflectance R are measured, and the refractive index n and the extinction coefficient k are calculated by the least squares method so that the error between the multiple measurement data and equation (1) is minimized.

[0092] The etching rate of phase shift film 13 by sulfuric acid / hydrogen peroxide is 0 nm / min to 0.05 nm / min. Sulfuric acid / hydrogen peroxide is used for removing a resist film, which will be described later, or for cleaning reflective mask 2. If the etching rate of phase shift film 13 by sulfuric acid / hydrogen peroxide is 0.05 nm / min or less, damage to phase shift film 13 during cleaning can be suppressed.

[0093] The method for forming the phase shift film 13 is, for example, DC sputtering, magnetron sputtering, or ion beam sputtering. The oxygen content of the phase shift film 13 can be controlled by the content of O2 gas in the sputtering gas. Also, the nitrogen content of the phase shift film 13 can be controlled by the content of N2 gas in the sputtering gas.

[0094] The etching mask film 14 is formed on the phase shift film 13 and is used to form an opening pattern 13a in the phase shift film 13. A resist film (not shown) is provided on the etching mask film 14. In the manufacturing process of the reflective mask 2, a first opening pattern is first formed in the resist film, then a second opening pattern is formed in the etching mask film 14 using the first opening pattern, and then a third opening pattern 13a is formed in the phase shift film 13 using the second opening pattern. The first opening pattern, the second opening pattern, and the third opening pattern 13a have the same dimensions and the same shape in a plan view (Z-axis direction view). The etching mask film 14 enables the resist film to be made thinner.

[0095] The etching mask film 14 contains at least one element selected from a fourth group consisting of Al, Hf, Y, Cr, Nb, Ti, Mo, Ta, and Si. The etching mask film 14 may contain at least one element selected from a fifth group consisting of O, N, and B in addition to the above elements.

[0096] The thickness of the etching mask film 14 is preferably 2 nm or more and 30 nm or less, more preferably 2 nm or more and 25 nm or less, and further preferably 2 nm or more and 10 nm or less.

[0097] The etching mask film 14 may be formed by, for example, DC sputtering, magnetron sputtering, or ion beam sputtering.

[0098] Next, a method for manufacturing a reflective mask blank 1 according to one embodiment will be described with reference to Fig. 8. The method for manufacturing the reflective mask blank 1 includes, for example, steps S101 to S105 shown in Fig. 8. In step S101, a substrate 10 is prepared. In step S102, a multilayer reflective film 11 is formed on a first main surface 10a of the substrate 10. In step S103, a protective film 12 is formed on the multilayer reflective film 11. In step S104, a phase shift film 13 is formed on the protective film 12. In step S105, an etching mask film 14 is formed on the phase shift film 13.

[0099] The method for manufacturing the reflective mask blank 1 only needs to include at least steps S101 to S104. The method for manufacturing the reflective mask blank 1 may further include a step of forming a functional film not shown in FIG.

[0100] Next, a method for manufacturing a reflective mask 2 according to an embodiment will be described with reference to FIG. 9. The method for manufacturing a reflective mask 2 includes steps S201 to S204 shown in FIG. 9. In step S201, a reflective mask blank 1 is prepared. In step S202, the etching mask film 14 is processed. A resist film (not shown) is provided on the etching mask film 14. First, a first opening pattern is formed in the resist film, and then a second opening pattern is formed in the etching mask film 14 using the first opening pattern. In step S203, a third opening pattern 13a is formed in the phase shift film 13 using the second opening pattern. In step S203, the phase shift film 13 is etched using an etching gas. In step S204, the resist film and the etching mask film 14 are removed. For example, sulfuric acid / hydrogen peroxide is used to remove the resist film. For example, an etching gas is used to remove the etching mask film 14. The etching gas used in step S204 (removing the etching mask film 14) may be the same as the etching gas used in step S203 (forming the opening pattern 13a). The manufacturing method of the reflective mask 2 only needs to include at least steps S201 and S203. EXAMPLES

[0101] Hereinafter, experimental data will be described with reference to Tables 1 to 4. Tables 1 and 2 show the film formation conditions for the phase shift film. Tables 3 and 4 show the measurement results of the properties of the phase shift film. The following Examples 1 to 12 and Examples 15 to 39 are working examples, and Examples 13 and 14 are comparative examples.

[0102] [Table 1]

[0103] [Table 2]

[0104] [Table 3]

[0105] [Table 4]

[0106] <Example 1> In Example 1, an EUV mask blank was produced that included a substrate, a multilayer reflective film, a protective film, and a phase shift film. A SiO2-TiO2-based glass substrate (6-inch (152 mm) square, 6.3 mm thick) was prepared as the substrate. This glass substrate had a thermal expansion coefficient of 0.02×10 at 20°C. -7 / °C, Young's modulus is 67 GPa, Poisson's ratio is 0.17, and specific stiffness is 3.07 × 10 7 m 2 / s 2 The quality assurance area of ​​the first main surface of the substrate was polished to a root-mean-square roughness (Rq) of 0.15 nm or less and a flatness of 100 nm or less. A 100 nm-thick Cr film was formed on the second main surface of the substrate by magnetron sputtering. The sheet resistance of the Cr film was 100 Ω / □.

[0107] The multilayer reflective film was a Mo / Si multilayer reflective film. The Mo / Si multilayer reflective film was formed by repeating the deposition of a Si layer (thickness 4.5 nm) and a Mo layer (thickness 2.3 nm) 40 times using the ion beam sputtering method. The total thickness of the Mo / Si multilayer reflective film was 272 nm ((4.5 nm + 2.3 nm) x 40).

[0108] As the protective film, a Rh film (thickness 2.5 nm) was formed. The Rh film was formed by DC sputtering. The reflectance of the EUV light by the multilayer reflective film after the protective film was formed, that is, the reflectance of the first EUV light L1 shown in FIG. 3, was a maximum of 64.5%.

[0109] The phase shift film was a RuTaON film formed by reactive sputtering. The conditions for forming the RuTaON film were as follows: Targets: Ru target and Ta target, Power density of Ru target: 8.8W / cm 2 , Power density of Ra target: 0.41W / cm 2 , Sputtering gas: A mixture of Ar gas, O2 gas, and N2 gas. Volume ratio of O2 gas in sputtering gas (O2 / (Ar+O2+N2)): 0.06, Volume ratio of N2 gas in the sputtering gas (N2 / (Ar+O2+N2)): 0.21.

[0110] <Example 2 to Example 39> In Examples 2 to 39, EUV mask blanks were produced under the same conditions as in Example 1, except for the deposition conditions of the phase shift film. The deposition conditions of the phase shift film are shown in Tables 1 and 2, and the measurement results of the properties of the phase shift film are shown in Tables 3 and 4.

[0111] <Evaluation> The composition of the phase shift film was measured using an X-ray photoelectron spectrometer (PHI 5000 VersaProbe) manufactured by ULVAC-PHI. The composition of the phase shift film was measured before and after the phase shift film was exposed to hydrogen gas. Tables 3 and 4 show the concentration of each element before hydrogen exposure, the O concentration after hydrogen exposure, and the change in O concentration due to hydrogen exposure. Hydrogen exposure was performed by cutting the test sample into 2.5 cm square specimens, attaching them to Si dummy substrates, setting them in a hydrogen irradiation test device simulating an EUV exposure device, and irradiating them with hydrogen (including hydrogen ions).

[0112] The crystallinity of the phase shift film was measured using an X-ray diffraction analyzer (MiniFlexII) manufactured by Rigaku Corporation. In Table 3, the full width at half maximum of "ND" means that no clear peak was observed in the 2θ range of 20° to 50°. As a representative example, the X-ray diffraction spectrum of Example 1 is shown in FIG.

[0113] The chemical shift of the phase shift film was measured for each sample using an X-ray photoelectron spectrometer (PHI 5000 VersaProbe) manufactured by ULVAC-PHI, Inc., following the procedure described above. The chemical shift is the magnitude (absolute value) of the difference between the binding energy of the maximum peak of the actually observed spectrum and the binding energy of the reference, or the magnitude of the difference in binding energy between the peak observed on the lowest energy side and the peak observed on the highest energy side among the peaks of the same level obtained when the observed spectrum is peak-separated. As a representative example, the chemical shift of Ru contained in the phase shift film of Example 1 is shown in Figure 5, and the chemical shift of Ta contained in the phase shift film of Example 1 is shown in Figure 6. In Figure 5, the binding energy of the actually observed peak was 0.1 eV lower than the binding energy of the reference, but this is considered to be within the margin of error.

[0114] As shown in Tables 3 and 4, in Examples 1 to 12 and 15 to 39, the chemical shift ΔE1 of the first element X1 (Ru, Pt, or Ir) was less than 0.3 eV, and the chemical shift ΔE3 of the third element X3 (Ta, Cr, Mo, W, or Hf) was greater than ΔE1, so that no decrease in O concentration due to hydrogen exposure was observed. Also, in Examples 1 to 7, 9 to 12, and 15 to 36, the full width at half maximum FWHM was 1.0° or more, and the crystallinity of the phase shift film was sufficiently low.

[0115] According to Example 13, the chemical shift ΔE3 of the third element X3 (Cr) was larger than the chemical shift ΔE1 of the first element X1 (Ru), but ΔE1 was 0.3 eV or more, and a decrease in the O concentration due to hydrogen exposure was observed. This shows that it is important to keep ΔE1 below 0.3 eV in order to improve the hydrogen resistance of the phase shift film.

[0116] According to Example 14, not only was the chemical shift ΔE1 of the first element X1 (Ru) 0.3 eV or more, but the third element X3 was not included, and the O concentration was significantly reduced by hydrogen exposure. This shows that the inclusion of the third element X3 and the larger chemical shift ΔE3 of the third element X3 than the chemical shift ΔE1 of the first element X1 also contribute to improving the hydrogen resistance of the phase shift film.

[0117] The reflective mask blank, the reflective mask, the manufacturing method of the reflective mask blank, and the manufacturing method of the reflective mask according to the present disclosure have been described above, but the present disclosure is not limited to the above-mentioned embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0118] This application claims priority based on Patent Application No. 2021-201671 filed with the Japan Patent Office on December 13, 2021, and Patent Application No. 2022-108641 filed with the Japan Patent Office on July 5, 2022, and the entire contents of Patent Application No. 2021-201671 and Patent Application No. 2022-108641 are incorporated by reference into this application. [Explanation of symbols]

[0119] 1 Reflective mask blank 2 Reflective mask 10 Substrate 11 Multilayer reflective film 12 Protective film 13 Phase shift film

Claims

1. A reflective mask blank having, in this order, a substrate, a multilayer reflective film that reflects EUV light, a protective film that protects the multilayer reflective film, and a phase shift film that shifts the phase of the EUV light, the phase shift film includes a first element X1 that is Ir and at least one second element X2 selected from a second group consisting of O, B, C, and N; The phase shift film has a 3d ５／２ or 4f ７／２ The chemical shift of the peak of the reflective mask blank is less than 0.3 eV.

2. 2. The reflective mask blank according to claim 1, wherein the phase shift film contains a third element X3 having a standard Gibbs energy of formation of at least one of oxide, boride, carbide, and nitride of −130 kJ / mol or less, and wherein a chemical shift of a peak of the third element X3 observed by X-ray photoelectron spectroscopy is larger than a chemical shift of a peak of the first element X1.

3. the phase shift film contains a third element X3, the standard Gibbs energy of formation of at least one of oxide, boride, carbide, and nitride being −500 kJ / mol or less; 2. The reflective mask blank according to claim 1, wherein the phase shift film has a chemical shift of a peak of the third element X3 observed by X-ray photoelectron spectroscopy of 1.0 eV or more.

4. 2. The reflective mask blank according to claim 1, wherein the phase shift film contains at least one second element X2 selected from a second group consisting of O, B, and C.

5. 5. The reflective mask blank according to claim 4, wherein the phase shift film contains O at 1 at % or more and less than 55 at %.

6. 4. The reflective mask blank according to claim 2, wherein the phase shift film contains the first element X1 in a total amount of 40 at % to 98 at %, the second element X2 in a total amount of 1 at % to 59 at %, and the third element X3 in a total amount of 1 at % to 30 at %.

7. 4. The reflective mask blank according to claim 2, wherein the third element X3 is at least one selected from a third group consisting of Ta, Nb, Mo, Cr, Si, Hf, W, and Re.

8. 4. The reflective mask blank according to claim 1, wherein the phase shift film has a full width at half maximum of a peak with the highest intensity in a 2θ range of 20° to 50° of 1.0° or more, as measured by an XRD method using CuKα radiation.

9. 4. The reflective mask blank according to claim 1, wherein the phase shift film has a thickness of 20 nm to 60 nm.

10. 4. The reflective mask blank according to claim 1, wherein the protective film contains at least one element selected from the group consisting of Ru, Rh, and Si.

11. an etching mask film on the phase shift film; 4. The reflective mask blank according to claim 1, wherein the etching mask film contains at least one element selected from a fourth group consisting of Al, Hf, Y, Cr, Nb, Ti, Mo, Ta, and Si.

12. 12. The reflective mask blank according to claim 11, wherein the etching mask film further contains at least one element selected from a fifth group consisting of O, N, and B.

13. A reflective mask blank according to any one of claims 1 to 3, A reflective mask including an aperture pattern in the phase shift film.

14. forming a multilayer reflective film on a substrate that reflects EUV light; forming a protective film on the multilayer reflective film to protect the multilayer reflective film; forming a phase shift film on the protective film to shift the phase of the EUV light; the phase shift film includes a first element X1 that is Ir and at least one second element X2 selected from a second group consisting of O, B, C, and N; The phase shift film has a 3d ５／２ or 4f ７／２ The chemical shift of the peak of the formula (I) is less than 0.3 eV.

15. preparing a reflective mask blank manufactured by the manufacturing method according to claim 14; forming an opening pattern in the phase shift film; A method for manufacturing a reflective mask comprising the steps of:

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