Reflective photomask blank and reflective photomask

Abstract

To provide a reflection type photomask blank and a reflection type photomask capable of sufficiently suppressing multiple exposure.SOLUTION: The light shielding groove 110A penetrating the hard mask layer 106, the absorber layer, and the reflective layer 102 is formed so as to surround the periphery of the circuit region 110B of the absorber layer 105, and the hard mask layer has a characteristic within a region surrounded by the following four equations when the refraction index is n, the extinction coefficient is k, and the thickness is dnm. K (n) = 2. 1n-1.8 (1) k (n) = - 1. 1n + 1.2 (2) k (n) = - 0. 049n + 0.123 (3) k (n) = 0. 028sin (23. 5n + 0. 8d + 1.4) + D (4) However, when d is equal to or greater than 8.5 and less than 11, D = 0. 0004d3 - 0. 01d2 + 0. 01d + 0.29, and when d is equal to or greater than 13.5 and equal to or less than 20, D = 0. - 0. + 0. - 0.75. 0002d3 01d2 17d.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a reflective photomask blank and a reflective photomask. [Background technology]

[0002] In the manufacturing process of semiconductor devices, the miniaturization of semiconductor devices has led to an increasing demand for miniaturization of photolithography technology. The minimum resolution dimension of circuit patterns in photolithography depends heavily on the wavelength of the exposure light source, and the shorter the wavelength, the smaller the minimum resolution dimension. For this reason, the exposure light source is gradually being replaced from the conventional 193 nm wavelength ArF excimer laser light to 13.5 nm wavelength extreme ultraviolet (EUV) light.

[0003] EUV light is absorbed to a high extent by most materials. For this reason, photomasks for EUV exposure are reflective. For example, a known reflective photomask has a reflective layer formed on a glass substrate, in which multiple combinations of molybdenum (Mo) films and silicon (Si) films are stacked, and an absorption layer containing tantalum (Ta) as a main component is formed thereon, and a circuit pattern is formed on this absorption layer (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-237174 Summary of the Invention [Problem to be solved by the invention]

[0005] The reflective photomask described above has an absorption layer mainly composed of tantalum (Ta) and having a thickness of 60 to 90 nm. When such a reflective photomask is used to transfer a circuit pattern onto a semiconductor device using exposure, depending on the relationship between the incident direction of the EUV light and the orientation of the circuit pattern on the reflective photomask, shadows may be generated at the edges and corners of the circuit pattern transferred onto the semiconductor device, resulting in a decrease in contrast. Such a decrease in contrast may result in increased line edge roughness and line width errors in the circuit pattern transferred onto the semiconductor device, potentially resulting in a decrease in the performance of the semiconductor device.

[0006] Therefore, while it is conceivable to use a material with a lower absorbency (extinction coefficient) and a lower refractive index for EUV light than tantalum (Ta) for the absorption layer of a reflective photomask, some materials may exhibit high reflectivity. If such a material with high reflectivity is used for the absorption layer of a reflective photomask, there is a risk that the exposure dose of the resist in the boundary region between adjacent chips will increase when exposed to light for multiple chips on a wafer. In other words, there is a risk that multiple exposures will occur in the boundary region between chips, which will affect the accuracy of circuit pattern formation, resulting in reduced chip quality and reduced throughput.

[0007] In view of the above, an object of the present invention is to provide a reflective photomask blank and a reflective photomask that enable sufficient suppression of multiple exposure. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the reflective photomask blank according to the present invention is a reflective photomask blank comprising a substrate, a reflective layer that reflects incident light, an absorbing layer that absorbs incident light, and a hard mask layer that protects the absorbing layer, laminated in this order, wherein the hard mask layer has a refractive index with respect to extreme ultraviolet light of n, an extinction coefficient of k, and a thickness of d (where d is equal to or greater than 8.5 and less than 11, or equal to or greater than 13.5 and less than 20) nm, and is characterized in that the hard mask layer is within a region surrounded by lines expressed by the following formulas (1) to (4):

[0009] k(n)=2.1n-1.8 (1) k(n)=-1.1n+1.2 (2) k(n)=-0.049n+0.123 (3) k(n)=0.028sin(23.5n+0.8d+1.4)+D (4)

[0010] However, when d is 8.5 or more and less than 11, D=0.0004d 3 -0.01d 2 +0.01d+0.29 (4a) and when d is 13.5 or more and 20 or less, D=0.0002d 3 -0.01d 2 +0.17d-0.75 (4b) is.

[0011] Furthermore, the reflective photomask blank according to the present invention is preferably the above-mentioned reflective photomask blank, in which the hard mask layer has a reflectance R of 3% or less with respect to extreme ultraviolet light.

[0012] Furthermore, the reflective photomask blank according to the present invention is preferably the above-mentioned reflective photomask blank, wherein the hard mask layer contains at least one element selected from the group consisting of Rh, Pd, Ag, Pt, Au, Os, Ir, Re, Cd, In, Co, Cr, Hg, Pb, Ti, Fe, Sn, Bi, Sb, Ni, Cu, Te, Zn, and I.

[0013] Furthermore, the reflective photomask blank according to the present invention is preferably the above-described reflective photomask blank, further comprising a protective layer laminated between the reflective layer and the absorbing layer to protect the reflective layer.

[0014] Furthermore, the reflective photomask blank according to the present invention is preferably the above-mentioned reflective photomask blank, further comprising a buffer layer laminated between the protective layer and the absorbing layer to protect the protective layer.

[0015] On the other hand, a reflective photomask according to the present invention for solving the above-mentioned problems is a reflective photomask comprising a substrate, a reflective layer that reflects incident light, and an absorbing layer that absorbs incident light and has a circuit region in which a circuit pattern is formed, stacked in this order, and further comprising a hard mask layer that is provided on the absorbing layer so as to surround the circuit region and protect the absorbing layer, and light-shielding grooves that penetrate the hard mask layer, the absorbing layer, and the reflective layer so as to surround the circuit region and suppress reflection of extreme ultraviolet light, and the hard mask layer has properties that allow it to be within a region surrounded by lines expressed by the following formulas (1) to (4), when the refractive index for extreme ultraviolet light is n, the extinction coefficient is k, and the thickness is d (where d is equal to or greater than 8.5 and less than 11, or equal to or greater than 13.5 and 20) nm:

[0016] k(n)=2.1n-1.8 (1) k(n)=-1.1n+1.2 (2) k(n)=-0.049n+0.123 (3) k(n)=0.028sin(23.5n+0.8d+1.4)+D (4)

[0017] However, when d is 8.5 or more and less than 11, D=0.0004d 3 -0.01d 2 +0.01d+0.29 (4a) and when d is 13.5 or more and 20 or less, D=0.0002d3 -0.01d 2 +0.17d-0.75 (4b) is.

[0018] Furthermore, in the reflective photomask according to the present invention, it is preferable that the hard mask layer has a reflectance R of 3% or less with respect to extreme ultraviolet light.

[0019] Furthermore, the reflective photomask according to the present invention is preferably the above-mentioned reflective photomask, wherein the hard mask layer contains at least one element selected from the group consisting of Rh, Pd, Ag, Pt, Au, Os, Ir, Re, Cd, In, Co, Cr, Hg, Pb, Ti, Fe, Sn, Bi, Sb, Ni, Cu, Te, Zn, and I.

[0020] Furthermore, the reflective photomask according to the present invention is preferably the above-described reflective photomask, further comprising a protective layer laminated between the reflective layer and the absorption layer to protect the reflective layer.

[0021] Furthermore, the reflective photomask according to the present invention is preferably the above-described reflective photomask, further comprising a buffer layer laminated between the protective layer and the absorbing layer to protect the protective layer.

[0022] In the present invention, in a method for producing a reflective photomask blank in which a substrate, a reflective layer that reflects incident light, an absorbing layer that absorbs incident light, and a hard mask layer that protects the absorbing layer are laminated in this order, the hard mask layer is produced from a material that exhibits properties within a region surrounded by lines expressed by the following formulas (1) to (4), where n is the refractive index for extreme ultraviolet light, k is the extinction coefficient, and d is the thickness (where d is 8.5 to less than 11 or 13.5 to 20 nm):

[0023] k(n)=2.1n-1.8 (1) k(n)=-1.1n+1.2 (2) k(n)=-0.049n+0.123 (3) k(n)=0.028sin(23.5n+0.8d+1.4)+D (4)

[0024] However, when d is 8.5 or more and less than 11, D=0.0004d 3 -0.01d 2 +0.01d+0.29 (4a) and when d is 13.5 or more and 20 or less, D=0.0002d 3 -0.01d 2 +0.17d-0.75 (4b) is. [Effects of the Invention]

[0025] According to the present invention, by providing a hard mask layer having properties within the region surrounded by the lines expressed by the above formulas (1) to (4) on an absorber layer, it is possible to provide a reflective photomask blank and a reflective photomask that can sufficiently suppress multiple exposure, while also providing low absorbency and a low refractive index for extreme ultraviolet rays. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a main embodiment of a reflective photomask blank according to the present invention. [Figure 2] 1 is a cross-sectional view showing a schematic configuration of a main embodiment of a reflective photomask according to the present invention. [Figure 3] FIG. 3 is a plan view seen from the direction of the arrow III in FIG. 2. [Figure 4] 4 is a diagram illustrating the steps of a method for manufacturing the reflective photomask of FIGS. [Figure 5] FIG. 1 is a graph showing the relationship between the extinction coefficient k and the refractive index n of various materials for EUV light when the thickness d of the hard mask layer is 17 nm. DETAILED DESCRIPTION OF THE INVENTION

[0027] Embodiments of a reflective photomask blank and a reflective photomask according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments described with reference to the drawings, and various technical matters described in each embodiment can be appropriately combined or substituted as necessary.

[0028] [Main embodiment] Main embodiments of the reflective photomask blank and reflective photomask according to the present invention will be described with reference to FIGS.

[0029] <Overall structure of reflective photomask blank> As shown in Fig. 1, a reflective layer 102 that reflects incident light is provided on a substrate 101. A protective layer 103 that protects the reflective layer 102 is provided on the reflective layer 102. A buffer layer 104 that protects the protective layer 103 is provided on the protective layer 103. An absorption layer 105 that absorbs incident light is provided on the buffer layer 104. A hard mask layer 106 that protects the absorption layer 105 is provided on the absorption layer 105. In Fig. 1, 107 denotes a back surface conductive film.

[0030] That is, the reflective photomask blank 100 according to this embodiment comprises a substrate 101, a reflective layer 102, an absorber layer 105, and a hard mask layer 106 laminated in this order. The reflective photomask blank 100 further comprises a protective layer 103 laminated between the reflective layer 102 and the absorber layer 105, and a buffer layer 104 laminated between the protective layer 103 and the absorber layer 105.

[0031] <Substrate 101> The substrate 101 is the base portion, and is preferably made of a material with low surface roughness, high flatness, and a low thermal expansion coefficient, such as SiO2-TiO2 glass.

[0032] <Reflection layer 102> The reflective layer 102 is a layer that reflects incident extreme ultraviolet (EUV) light. The reflective layer 102 can be removed by fluorine-based (or chlorine-based) dry etching, and is made by laminating multiple combinations (e.g., 40 combinations) of material films (e.g., silicon (Si) films and molybdenum (Mo) films) that have significantly different refractive indices for EUV light. The reflective layer 102 preferably has a thickness of approximately 280 nm.

[0033] <Protective layer 103> The protective layer 103 is made of a material (such as Ru) that is resistant to fluorine-based (or chlorine-based) dry etching so as to function as an etching stopper that prevents damage to the reflective layer 102. The protective layer 103 preferably has a thickness of about 2.5 nm.

[0034] <Buffer layer 104> The buffer layer 104 is made of a material that is resistant to chlorine-based (or fluorine-based) dry etching so that it can function as an etching stopper to prevent damage to the protective layer 103, but is also removable by fluorine-based (or chlorine-based) dry etching.

[0035] <Absorption layer 105> The absorbing layer 105 is a layer that absorbs EUV light, which is the exposure light, and is removable by chlorine-based (or fluorine-based) dry etching to form a circuit pattern, while being resistant to fluorine-based (or chlorine-based) dry etching. The absorbing layer 105 is made of a material (e.g., RuCr) that has low absorption (extinction coefficient k≧0.02) and a low refractive index (n≧0.9) with respect to EUV light, but exhibits high reflectance (R>3%). These materials often have a reflectance R of approximately 10-15% (especially 11-12%) with respect to EUV light.

[0036] <Hard mask layer 106> The hard mask layer 106 can be removed by fluorine-based (or chlorine-based) dry etching, but is resistant to chlorine-based (or fluorine-based) dry etching. The hard mask layer 106 has a refractive index for EUV light of n, an extinction coefficient of k, and a thickness of d (where d is equal to or greater than 8.5 and less than 11, or equal to or greater than 13.5 and less than 20) nm, and the hard mask layer 106 has a property of being within a region surrounded by lines expressed by the following formulas (1) to (4):

[0037] k(n)=2.1n-1.8 (1) k(n)=-1.1n+1.2 (2) k(n)=-0.049n+0.123 (3) k(n)=0.028sin(23.5n+0.8d+1.4)+D (4)

[0038] However, when d is 8.5 or more and less than 11, D=0.0004d 3 -0.01d 2 +0.01d+0.29 (4a) and when d is 13.5 or more and 20 or less, D=0.0002d 3 -0.01d 2 +0.17d-0.75 (4b) is.

[0039] Examples of the hard mask layer 106 having properties falling within the region surrounded by the lines expressed by the above formulas (1) to (4) include materials containing at least one element selected from the group consisting of Rh, Pd, Ag, Pt, Au, Os, Ir, Re, Cd, In, Co, Cr, Hg, Pb, Ti, Fe, Sn, Bi, Sb, Ni, Cu, Te, Zn, and I. In addition to the above elements, examples of the hard mask layer 106 include alloys containing the above elements, and various compounds of the above elements, such as oxides (e.g., RhO3, Ag2O, PtO2, In2O3, CoO, Cr2O3, etc.), nitrides (e.g., Ag3N, ReN, CrN, Fe2N, etc.), and hydrides (e.g., HI, CdH2, CoH2, TiH2, CuH, etc.).

[0040] Specifically, for example, the relationship between the extinction coefficient k and the refractive index n of various materials for EUV light when the thickness d of the hard mask layer is 17 nm (d=17 nm) is shown in Figure 5. As shown in Figure 5, the above formula (1) indicates the lower limit of the refractive index n, the above formula (2) indicates the upper limit of the refractive index n, the above formula (3) indicates the upper limit of the extinction coefficient k, and the above formula (4) indicates the lower limit of the extinction coefficient k. A hard mask layer made of the above materials that exists within the region surrounded by the lines represented by these formulas (1) to (4) has a reflectance R for EUV light of 3% or less (R≦3%) (see [Examples] below).

[0041] That is, the above formula (4) is set from the thickness d of the hard mask layer, and the above region is set in combination with the above formulas (1) to (3), and a material whose characteristics exist within that region is selected for the hard mask layer. In other words, the hard mask layer is manufactured from a material that exhibits the characteristics within the region surrounded by the lines expressed by the above formulas (1) to (4).

[0042] [Backside conductive film 107] The back surface conductive film 107 is provided so that it can be fixed by an electrostatic chuck when it is installed in an exposure machine, and is made of, for example, a Cr-based material or a Ta-based material.

[0043] <Overall structure of reflective photomask> 2 and 3, the reflective photomask according to this embodiment, which uses the above-described reflective photomask blank 100, includes a substrate 101, a reflective layer 102, a protective layer 103, a buffer layer 104, an absorbing layer 105, a hard mask layer 106, and a back surface conductive film 107. The reflective photomask 110 is provided with a circuit region 110A in which a circuit pattern 110a to be transferred to a semiconductor device is formed in the central part of the absorbing layer 105.

[0044] The reflective photomask 110 has a hard mask layer 106 provided on the absorption layer 105 so as to surround the periphery of the circuit region 110A. The reflective photomask 110 also has a light-shielding groove (light-shielding region) 110B formed in the reflective photomask 110, which penetrates the hard mask layer 106, absorption layer 105, buffer layer 104, protective layer 103, and reflective layer 102 so as to surround the periphery of the circuit region 110A and suppresses reflection of EUV light. This light-shielding groove 110B is formed into the substrate 101, and preferably has a width of 2.5 mm or more and 3.5 mm or less.

[0045] <Method for manufacturing the reflective photomask 110> A method for manufacturing such a reflective photomask 110 according to this embodiment will be described with reference to FIG.

[0046] First, a resist solution is applied onto the hard mask layer 106 of the reflective photomask blank 100 to form a resist film M1 (see FIG. 4A), a circuit pattern is written onto the resist film M1 using an electron beam lithography device, and the resist film M1 is developed using a developer or the like to form a circuit pattern Pc on the resist film M1 (see FIG. 4B). Then, the circuit pattern Pc is formed on the hard mask layer 106 by fluorine-based dry etching (see FIG. 4C), and after the resist film M1 is peeled and removed (see FIG. 4D), a circuit pattern 110a is formed on the absorption layer 105 by chlorine-based dry etching (see FIG. 4E).

[0047] Next, a resist solution is applied to the hard mask layer 106 in a position surrounding the circuit pattern Pc to form a resist film M2 (see FIG. 4F), a groove pattern is written on the resist film M2 using an electron beam lithography system, and the resist film M2 is developed using a developer or the like to form a groove pattern Pg in the resist film M2 (see FIG. 4G). Then, a part of the light-shielding groove 110B is formed in the hard mask layer 106 by fluorine-based dry etching, and the circuit pattern Pc of the hard mask layer 106 is etched away (see FIG. 4H), and then the resist film M2 is peeled off and removed (see FIG. 4I).

[0048] Next, a resist solution is applied to the entire surface so as to fill in the circuit pattern 110a and a portion of the light-shielding grooves 110B to form a resist film M3 (see FIG. 4J). A groove pattern is written on the resist film M3 using an electron beam lithography system, and the resist film M3 is developed using a developer or the like to form a groove pattern Pg in the resist film M3 (see FIG. 4K). Then, chlorine-based dry etching is used to form light-shielding grooves 110B that penetrate the absorption layer 105, buffer layer 104, protective layer 103, and reflective layer 102 and reach the inside of the substrate 101 (see FIG. 4L). Finally, the resist film M3 is peeled off to obtain the reflective photomask 110 (see FIG. 2).

[0049] <Action and effect> In this embodiment, the absorbing layer 105 is made of a material (e.g., RuCr) that exhibits low absorption (extinction coefficient k≧0.02) and a low refractive index (n≧0.9). Therefore, during the fabrication of semiconductor devices, reflection and scattering occurring during the photolithography process can be reduced, improving the contrast and resolution of the pattern, and improving the optical properties and controllability of the patterning process. On the other hand, the high reflectivity (R>3%) of the material can cause dimensional variations and poor resolution of the circuit pattern at the edges and corners of the wafer chips.

[0050] Therefore, in this embodiment, a light-shielding groove 110B is formed so as to surround the circuit region 110A, thereby providing a light-shielding region 110B that exhibits high light-shielding properties against the wavelength of EUV light around the circuit region 110A. This makes it possible to suppress reflection of EUV light in the light-shielding region 110B and prevent multiple exposures in the boundary regions between adjacent chips.

[0051] Furthermore, a hard mask layer 106 having the characteristics within the region surrounded by the lines expressed by the above formulas (1) to (4) is provided on the absorption layer 105 so as to surround the periphery of the circuit region 110A while avoiding the light-shielding groove (light-shielding region) 110B. This makes it possible to achieve low absorbency (extinction coefficient k≧0.02) and a low refractive index (n≧0.9) for EUV light, while also achieving low reflectance (R≦3%) on the front surface side.

[0052] Therefore, according to this embodiment, it is possible to provide a reflective photomask blank 100 and a reflective photomask 110 that can sufficiently suppress multiple exposure.

[0053] [Other embodiments] In the above-described embodiment, the reflective photomask blank 100 and the reflective photomask 110 are provided with the protective layer 103, but the present invention is not limited to this. As another embodiment, for example, depending on the material of the reflective layer 102, etching conditions, etc., it is also possible to provide a reflective photomask blank and a reflective photomask in which the protective layer 103 is omitted.

[0054] In the above-described embodiment, the reflective photomask blank 100 and the reflective photomask 110 are provided with the buffer layer 104, but the present invention is not limited to this. As another embodiment, for example, depending on the material of the protective layer 103, the etching conditions, etc., it is also possible to provide a reflective photomask blank and a reflective photomask that omit the buffer layer 104. [Example]

[0055] Examples conducted to confirm the effects of the reflective photomask blank and reflective photomask according to the present invention will be specifically described below. Note that the present invention is not limited to the following examples.

[0056] [Implementation method] When various materials were applied to the hard mask layer 106 of the reflective photomask 110 according to the embodiment described above, the reflectance R of the hard mask layer 106 at EUV light (wavelength 13.5 nm) corresponding to the thickness d of the hard mask layer 106 was calculated by simulation. The results are shown in Table 1 below.

[0057] [Table 1]

[0058] [Implementation results] As can be seen from Table 1, in Comparative Examples 1 to 4, which satisfied the formulas (1) to (3) but did not satisfy the formula (4) because the thickness d was less than 8.5 nm (d<8.5 nm), the reflectance R was 9% or more. In Comparative Examples 5 to 8, which satisfied the formulas (1) to (3) but did not satisfy the formula (4) because the thickness d was 11 nm or more and less than 13.5 nm (11 nm≦d<13.5 nm), the reflectance R was more than 3% and 7% or less.

[0059] In contrast, in Examples 1 to 10, which satisfied the formulas (1) to (3) and had a thickness d of 8.5 nm or more and less than 11 nm (8.5 nm≦d<11 nm), thereby satisfying the formula (4), the reflectance R was 3% or less (R≦3%), more specifically, 2.4% or less (R≦2.4%). Also, in Examples 11 to 20, which satisfied the formulas (1) to (3) and had a thickness d of 13.5 nm or more and 20 nm or less (13.5 nm≦d≦20 nm), thereby satisfying the formula (4), the reflectance R was 3% or less (R≦3%), more specifically, 2.4% or less (R≦2.4%).

[0060] From the above, the effects of the reflective photomask blank and reflective photomask according to the present invention were confirmed. [Industrial Applicability]

[0061] The present invention can provide a reflective photomask blank and a reflective photomask that can sufficiently suppress multiple exposure, and can therefore be used extremely advantageously in various industries including the semiconductor industry. [Explanation of symbols]

[0062] 100 Reflective Photomask Blanks 101 Substrate 102 Reflective layer 103 Protective layer 104 Buffer layer 105 Absorbing layer 106 Hard mask layer 107 Backside conductive film 110 Reflective photomask 110A circuit area 110a circuit pattern 110B Light-shielding groove (light-shielding area) M1~M3 Resist film PC circuit pattern Pg Groove Pattern

Claims

1. A substrate; a reflective layer that reflects incident light; an absorption layer that absorbs incident light; a hard mask layer protecting the absorber layer; a reflective photomask blank in which the above are laminated in this order, The hard mask layer has a refractive index for extreme ultraviolet light of n, an extinction coefficient of k, and a thickness of d (where d is equal to or greater than 8.5 and less than 11, or equal to or greater than 13.5 and less than 20) nm, and the properties fall within a region surrounded by lines expressed by the following formulas (1) to (4): A reflective photomask blank characterized by: k(n)=2.1n-1.8 (1) k(n)=-1.1n+1.2 (2) k(n)=-0.049n+0.123 (3) k(n)=0.028sin(23.5n+0.8d+1.4)+D (4) However, when d is 8.5 or more and less than 11, D=0.0004$ ３ -0.01d ２ +0.01$+0.29 (4a) and when d is 13.5 or more and 20 or less, D=0.0002d ３ -0.01d ２ +0.17d-0.75 (4b) is.

2. The hard mask layer has a reflectance R of 3% or less for extreme ultraviolet rays.

2. The reflective photomask blank according to claim 1.

3. The hard mask layer contains at least one element selected from the group consisting of Rh, Pd, Ag, Pt, Au, Os, Ir, Re, Cd, In, Co, Cr, Hg, Pb, Ti, Fe, Sn, Bi, Sb, Ni, Cu, Te, Zn, and I.

2. The reflective photomask blank according to claim 1.

4. a protective layer laminated between the reflective layer and the absorbing layer to protect the reflective layer; 2. The reflective photomask blank according to claim 1.

5. a buffer layer laminated between the protective layer and the absorbent layer to protect the protective layer; 5. The reflective photomask blank according to claim 4.

6. A substrate; a reflective layer that reflects incident light; an absorption layer that absorbs incident light and has a circuit region on which a circuit pattern is formed; A reflective photomask in which the above are laminated in this order, a hard mask layer provided on the absorption layer to surround the circuit region and protect the absorption layer; a light-shielding groove is formed through the hard mask layer, the absorption layer, and the reflection layer to surround the circuit region and suppress reflection of extreme ultraviolet rays; The hard mask layer has a refractive index for extreme ultraviolet light of n, an extinction coefficient of k, and a thickness of d (where d is equal to or greater than 8.5 and less than 11, or equal to or greater than 13.5 and less than 20) nm, and the properties fall within a region surrounded by lines expressed by the following formulas (1) to (4): A reflective photomask characterized by: k(n)=2.1n-1.8 (1) k(n)=-1.1n+1.2 (2) k(n)=-0.049n+0.123 (3) k(n)=0.028sin(23.5n+0.8d+1.4)+D (4) However, when d is 8.5 or more and less than 11, D=0.0004$ ３ -0.01d ２ +0.01$+0.29 (4a) and when d is 13.5 or more and 20 or less, D=0.0002d ３ -0.01d ２ +0.17d-0.75 (4b) is.

7. The hard mask layer has a reflectance R of 3% or less for extreme ultraviolet rays.

7. The reflective photomask according to claim 6.

8. The hard mask layer contains at least one element selected from the group consisting of Rh, Pd, Ag, Pt, Au, Os, Ir, Re, Cd, In, Co, Cr, Hg, Pb, Ti, Fe, Sn, Bi, Sb, Ni, Cu, Te, Zn, and I.

7. The reflective photomask according to claim 6.

9. a protective layer laminated between the reflective layer and the absorbing layer to protect the reflective layer; 7. The reflective photomask according to claim 6.

10. a buffer layer laminated between the protective layer and the absorbent layer to protect the protective layer; 10. The reflective photomask according to claim 9.

11. A substrate; a reflective layer that reflects incident light; an absorption layer that absorbs incident light; a hard mask layer protecting the absorber layer; In a method for manufacturing a reflective photomask blank, The hard mask layer is manufactured from a material that exhibits properties within the region surrounded by the lines expressed by the following formulas (1) to (4), where n is the refractive index for extreme ultraviolet light, k is the extinction coefficient, and d is the thickness (where d is 8.5 to less than 11 or 13.5 to 20 nm).

1. A method for producing a reflective photomask blank, comprising: k(n)=2.1n-1.8 (1) k(n)=-1.1n+1.2 (2) k(n)=-0.049n+0.123 (3) k(n)=0.028sin(23.5n+0.8d+1.4)+D (4) However, when d is 8.5 or more and less than 11, D=0.0004$ ３ -0.01d ２ +0.01$+0.29 (4a) and when d is 13.5 or more and 20 or less, D=0.0002d ３ -0.01d ２ +0.17d-0.75 (4b) is.

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