Reflective mask blank, reflective mask, and method for manufacturing a semiconductor device

Abstract

This invention provides a reflective mask blank for manufacturing reflective masks that can keep changes in pattern dimensions within an acceptable range even when subjected to repeated heating and cooling treatments on the mask, such as mask washing and exposure during the mask manufacturing process and use. [Solution] The invention comprises a substrate, a multilayer reflective film formed on the substrate, and an absorber film formed on the multilayer reflective film. The absorber film includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis using X-ray diffraction with an in-plane method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis using X-ray diffraction with an out-of-plane method.

Description

Technical Field

[0001] The present invention relates to a reflective mask blank and a reflective mask used in the manufacture of semiconductor devices, and a method for manufacturing semiconductor devices.

Background Art

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

[0003] In recent years, in the semiconductor industry, with the increasing integration of semiconductor devices, there has been a need for fine patterns that exceed the transfer limit of the conventional photolithography method using ultraviolet light. As a technique that enables such fine pattern formation, there is EUV lithography, an exposure technique using extreme ultraviolet (hereinafter referred to as "EUV") light. Here, EUV light refers to light in the wavelength band of the soft X-ray region or the vacuum ultraviolet region. Specifically, light in the vicinity of 13.5 nm including a wavelength of 13.5 nm is used as EUV light.

[0004] As a transfer mask used in such EUV lithography, a reflective mask has been conventionally proposed. For example, in a prior art document (Patent Document 1), a reflective mask blank and a reflective mask having a multilayer reflective film that reflects exposure light (EUV light), a buffer layer, and an absorber layer made of a tantalum-based material that absorbs exposure light (EUV light) on a substrate are disclosed.

[0005] Furthermore, in order to further improve the transfer resolution of EUV lithography, development is underway on phase-shift masks for EUV exposure that apply the principle of halftone masks used in conventional excimer laser exposure to EUV lithography using reflective optics. For example, prior art document (Patent Document 2) discloses a reflective mask blank and a reflective mask having a multilayer reflective film and a phase-shift film on a substrate in that order. In Patent Document 2, this phase-shift film includes a lower layer and an uppermost layer containing ruthenium and chromium in predetermined total content. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2004-006799 [Patent Document 1] Japanese Patent Publication No. 2021-081644 [Overview of the project] [Problems that the invention aims to solve]

[0007] Furthermore, the absorber film for the above-mentioned phase-shift type EUV mask blank requires a phase-shift film with a low refractive index for EUV light and a large extinction coefficient. Such a phase-shift film may have greater film stress than conventional absorber films. Heating and cooling treatments of the mask, such as the mask manufacturing process, mask cleaning during use, and exposure, can relieve the film stress of the absorber film. If the absorber film (phase-shift film) has high film stress, the change in film stress before and after such heating and cooling treatments may become too large. As a result, the pattern shape changes, and the pattern dimensions change before and after the heating and cooling treatment, which can ultimately reduce the mask life.

[0008] Therefore, the present invention has been made to solve these conventional problems. The first object of the present invention is to provide a reflective mask blank and a reflective mask for manufacturing a reflective mask that can keep changes in pattern dimensions within an acceptable range even when repeated heating and cooling treatments on the mask, such as the mask manufacturing process, mask washing during use, and exposure, are performed on the mask. Furthermore, a second object of the present invention is to provide a method for manufacturing a semiconductor device using this reflective mask. [Means for solving the problem]

[0009] To solve the problems of the past, the inventors diligently continued their research, focusing on the structure obtained by analyzing absorber films using X-ray diffraction. As a result, they completed the following invention.

[0010] (Composition 1) A reflective mask blank comprising a substrate, a multilayer reflective film formed on the substrate, and an absorber film formed on the multilayer reflective film, wherein the absorber film includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis by X-ray diffraction using the in-plane method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis by X-ray diffraction using the out-of-plane method.

[0011] (Configuration 2) The reflective mask blank according to configuration 1, characterized in that the absorbent membrane has a lower layer provided below the first layer. (Composition 3) The reflective mask blank according to configuration 1 or 2, characterized in that the absorber film contains at least one of ruthenium, platinum, and iridium.

[0012] (Composition 4) The reflective mask blank according to any one of configurations 1 to 3, characterized in that the first layer has a crystallite size of 3 nm or more. (Composition 5) The reflective mask blank according to any one of configurations 1 to 4, characterized in that the first layer has a crystallite size that is 2 nm or more larger than the crystallite size of other layers provided below or above the first layer.

[0013] (Composition 6) The reflective mask blank according to any one of configurations 1 to 5, characterized in that the first layer is etchable with a fluorine-containing gas. (Composition 7) A reflective mask blank according to any one of configurations 1 to 6, characterized in that the ratio of the thickness of the first layer to the thickness of the absorbent film is 0.5 or more.

[0014] (Composition 8) A reflective mask comprising a substrate, a multilayer reflective film formed on the substrate, and an absorber film formed on the multilayer reflective film on which a transfer pattern is formed, wherein the absorber film includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis by X-ray diffraction using the in-plane method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis by X-ray diffraction using the out-of-plane method.

[0015] (Composition 9) The reflective mask according to configuration 8, characterized in that the absorbent membrane has a lower layer provided below the first layer. (Composition 10) The reflective mask according to configuration 8 or 9, characterized in that the absorber membrane contains at least one of ruthenium, platinum, and iridium.

[0016] (Composition 11) The reflective mask according to any one of configurations 8 to 10, characterized in that the first layer has a crystallite size of 3 nm or more. (Composition 12) The reflective mask according to any one of configurations 8 to 11, characterized in that the first layer has a crystallite size that is 2 nm or more larger than the crystallite size of other layers provided below or above the first layer.

[0017] (Configuration 13) The reflective mask according to any one of Configurations 8 to 12, wherein the first layer is etchable with a fluorine-containing gas. (Configuration 14) The reflective mask according to any one of Configurations 8 to 13, wherein the ratio of the film thickness of the first layer to the film thickness of the absorber film is 0.5 or more.

[0018] (Configuration 15) A method for manufacturing a semiconductor device, including using the reflective mask according to any one of Configurations 8 to 14 and transferring the transfer pattern of the reflective mask to a transfer target on a semiconductor substrate.

Advantages of the Invention

[0019] According to the present invention, a reflective mask blank for manufacturing a reflective mask capable of suppressing a change in pattern dimensions within an allowable range even when heat treatment such as a mask manufacturing process, mask cleaning during mask use, and exposure is repeated, and a reflective mask can be provided. Further, according to the present invention, a method for manufacturing a semiconductor device capable of performing high-precision pattern transfer using this reflective mask can be provided.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic cross-sectional view showing an embodiment (first embodiment) of the reflective mask blank of the present invention. [Figure 2] It is a schematic cross-sectional view showing another embodiment (second embodiment) of the reflective mask blank of the present invention. [Figure 3] It is a schematic cross-sectional view showing another embodiment (third embodiment) of the reflective mask blank of the present invention. [Figure 4] It is a schematic cross-sectional view showing an embodiment of the reflective mask of the present invention.

Modes for Carrying Out the Invention

[0021] Embodiments of the present invention will be described in detail below. [Reflective Mask Blank] First, the reflective mask blank of the present invention will be described. In this specification, EUV light refers to light (electromagnetic waves) with a wavelength of 13.5 nm or near 13.5 nm, including 13.5 nm. Specifically, in this invention, EUV light refers to light in the wavelength range of 13.395 nm to 13.665 nm. In this specification, light includes not only visible light but also electromagnetic waves.

[0022] Figure 1 shows one embodiment (first embodiment) of the reflective mask blank of the present invention. Figure 2 shows another embodiment (second embodiment) of the reflective mask blank of the present invention. Furthermore, Figure 3 shows yet another embodiment (third embodiment) of the reflective mask blank of the present invention.

[0023] Figure 1 shows a reflective mask blank 10A of a first embodiment, comprising a substrate 1, a multilayer reflective film 3 formed on the substrate 1, and an absorber film 5 formed on the multilayer reflective film 3. The reflective mask blank 10A of the first embodiment has a back surface conductive film 2 on the back surface of the substrate 1. Figure 2 also shows a reflective mask blank 10B of a second embodiment, comprising a substrate 1, a multilayer reflective film 3 formed on the substrate 1, a protective film 4 formed on the multilayer reflective film 3, and an absorber film 5 formed on the protective film 4. The reflective mask blank 10B of the second embodiment has a back surface conductive film 2 on the back surface of the substrate 1. The reflective mask blank 10B of the second embodiment differs from the reflective mask blank 10A of the first embodiment in that the protective film 4 (details will be described later) is formed between the multilayer reflective film 3 and the absorber film 5. Furthermore, Figure 3 shows a reflective mask blank 10C of a third embodiment, comprising a substrate 1, a multilayer reflective film 3 formed on the substrate 1, a protective film 4 formed on the multilayer reflective film 3, an absorber film 5 formed on the protective film 4, and an etching mask film 6 formed on the absorber film 5. The reflective mask blank 10C of the third embodiment has a back surface conductive film 2 on the back surface of the substrate 1. The reflective mask blank 10C of the third embodiment differs from the reflective mask blank 10B of the second embodiment in that the etching mask film 6 (details described later) is formed on the absorber film 5.

[0024] <First Embodiment> Figure 1 is a schematic cross-sectional view showing one embodiment (first embodiment) of the reflective mask blank of the present invention. As shown in Figure 1, the reflective mask blank 10A of this embodiment comprises a substrate 1, a multilayer reflective film 3 formed on the substrate 1, and an absorber film 5 formed on the multilayer reflective film 3. The reflective mask blank 10A of this embodiment has a back surface conductive film 2 on the back surface of the substrate 1. Furthermore, in the reflective mask blank 10A of this embodiment, the absorber film 5 includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis using X-ray diffraction with an in-plane method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis using X-ray diffraction with an out-of-plane method.

[0025] In the reflective mask blank 10A of this embodiment, the substrate 1 is such that, in the case of EUV exposure, in order to prevent pattern distortion due to heat during exposure, it is 0±1.0×10 -7 Within the range of / ℃, more preferably 0±0.3×10 -7 Materials with a low coefficient of thermal expansion within the range of / °C are preferably used. Examples of materials with a low coefficient of thermal expansion within this range include SiO2-TiO2 glass and multi-component glass ceramics.

[0026] The main surface on which the transfer pattern is formed on the substrate 1 is surface-processed to achieve high flatness, at least from the viewpoint of improving pattern transfer accuracy and positional accuracy. For EUV exposure, the flatness of the main surface on the side of the substrate 1 on which the transfer pattern is formed is preferably 0.1 μm or less, and particularly preferably 0.05 μm or less, in a region of, for example, 142 mm × 142 mm. The main surface on the opposite side of the main surface on which the transfer pattern is formed (the back surface) is the surface that is electrostatically chucked when the substrate is set in the exposure apparatus. The flatness of this back surface is preferably 0.1 μm or less, and more preferably 0.05 μm or less, in a region of, for example, 142 mm × 142 mm.

[0027] Furthermore, as described above, a material having a low coefficient of thermal expansion, such as SiO2-TiO2 glass, is preferably used as the substrate 1. With such materials, it can be difficult to achieve high smoothness, such as a root mean square roughness (Rq) of 0.1 nm or less, by precision polishing. For this reason, a base layer (not shown) may be formed on the surface of the substrate 1 in order to reduce the surface roughness of the substrate 1 or to reduce defects on the surface of the substrate 1. The material of such a base layer does not need to be translucent to exposure light, and a material that can be obtained with high smoothness and good defect quality when the surface of the base layer is precision polished is preferably selected. For example, Si or silicon compounds containing Si (e.g., SiO2, SiON, etc.) can be obtained with high smoothness and good defect quality when precision polished, and are therefore preferably used as a base layer material. Si is particularly preferred as the material for the base layer.

[0028] The surface of the substrate layer is preferably precisely polished to achieve the smoothness required for a substrate used as a reflective mask blank. It is desirable that the surface of the substrate layer be precisely polished to a root mean square roughness (Rq) of 0.15 nm or less, particularly preferably 0.1 nm or less. Furthermore, considering the influence on the surface of the multilayer reflective film 2 formed on the substrate layer, the surface of the substrate layer is precisely polished such that, in relation to the maximum height (Rmax), Rmax / Rq is preferably 2 to 10, particularly preferably 2 to 8. The thickness of the substrate layer is preferably in the range of, for example, 10 nm to 300 nm.

[0029] The multilayer reflective film 3 provided on the substrate 1 (or underlayer) includes multiple sets of low refractive index layers and high refractive index layers. Specifically, the multilayer reflective film 3 is a multilayer film in which low refractive index layers and high refractive index layers are alternately stacked. Generally, the multilayer reflective film 3 is a multilayer film in which thin films of heavy elements or their compounds and thin films of light elements or their compounds are alternately stacked for about 30 to 60 periods. For example, as a multilayer reflective film for EUV light with a wavelength of 13-14 nm, a Mo / Si periodic multilayer film, in which Mo films and Si films are alternately stacked for about 40 periods, is preferably used. Other multilayer reflective films used in the EUV light region include Ru / Si periodic multilayer films, Mo / Be periodic multilayer films, Mo compound / Si compound periodic multilayer films, Si / Nb periodic multilayer films, Si / Mo / Ru periodic multilayer films, Si / Mo / Ru periodic multilayer films, Si / Mo / Ru / Mo periodic multilayer films, and Si / Ru / Mo / Ru periodic multilayer films. The material of the multilayer reflective film should be appropriately selected according to the exposure wavelength. In addition, other functional layers may be formed between the low refractive index layer and the high refractive index layer. For example, the other functional layer may be a film that reduces or suppresses diffusion between the low refractive index layer and the high refractive index layer.

[0030] Typically, a protective film 4 is provided on the multilayer reflective film 3 for the purpose of protecting the multilayer reflective film 3 during patterning or pattern modification of the absorber film 5. The protective film 4 is sometimes called a capping layer. Details of the protective film 4 provided on the multilayer reflective film 3 will be described in the second embodiment described later.

[0031] The method for depositing the underlayer and the multilayer reflective film 3 described above is not particularly limited, but ion beam sputtering and magnetron sputtering are generally preferred. At least one of the sputtering target and sputtering gas used for depositing each film (layer) contains the elements that constitute each film (layer). By using such a sputtering target and sputtering gas and adjusting various conditions such as the power applied to the sputtering target and the gas flow rate, each film (layer) can be formed.

[0032] Next, the absorbent membrane 5 described above will be explained. An absorber film 5 that absorbs EUV light is formed on the multilayer reflective film 3. If a protective film 4 is provided on the multilayer reflective film 3, the absorber film 5 is formed on the protective film 4. The absorber film 5 absorbs EUV light, which is the exposure light. The absorber film 5 should be configured such that, in a reflective mask 20 (see Figure 4) fabricated using a reflective mask blank, there is a desired reflectance difference between the light reflected from the multilayer reflective film 3 or protective film 4 and the light reflected from the transfer pattern (absorber film pattern) 5a formed on the absorber film 5. For example, the reflectance difference of the absorber film 5 with respect to EUV light is selected to be between 0.1% and 40%.

[0033] Furthermore, the absorber film 5 may be configured to have a desired phase difference between the reflected light from the multilayer reflective film 3 or protective film 4 and the reflected light from the transfer pattern (absorber film pattern) 5a, in addition to the above-mentioned reflectance difference. When the reflected light from the transfer pattern (absorber film pattern) 5a has a desired phase difference with respect to the reflected light from the multilayer reflective film 3 or protective film 4, the absorber film 5 in the reflective mask blank may be referred to as a phase-shift film. When improving contrast by providing a desired phase difference between the reflected light from the multilayer reflective film 3 or protective film 4 and the reflected light from the transfer pattern (absorber film pattern) 5a, it is preferable to set the phase difference with respect to EUV light in the range of 170 to 260 degrees, and it is preferable to set the reflectance difference of the absorber film 5 with respect to EUV light to 3% or more and 40% or less.

[0034] The absorber film 5 described above may be a single layer or a laminated structure. In the case of a laminated structure, it may be a laminated film of the same material or a laminated film of different materials. The laminated film may have materials and composition that change stepwise and / or continuously in the direction of film thickness.

[0035] As described above, in the reflective mask blank 10A of this embodiment, the absorber film 5 includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis by X-ray diffraction using the in-plane method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis by X-ray diffraction using the out-of-plane method.

[0036] X-ray diffraction measurement involves irradiating the surface of a sample with X-rays at an incidence angle ω and measuring the diffraction angle 2θ. In the in-plane method, the X-rays are incident at a very shallow incidence angle, for example, 0.2° to 0.5°, onto the sample surface. Therefore, X-ray diffraction measurements using the in-plane method can capture a lot of information about the area near the surface of the sample. Furthermore, the in-plane method is a measurement method in which the incident X-rays and diffracted X-rays are almost parallel to the surface of the sample. Consequently, X-ray diffraction measurements using the in-plane method tend to reflect the diffracted light from planes perpendicular to the surface of the crystallites in the sample. On the other hand, the out-of-plane method is a measurement method in which X-rays are incident at an incidence angle in the range of 5° to 90°, for example. Therefore, X-ray diffraction measurements using the out-of-plane method can capture a lot of information about the deeper parts of the sample. Furthermore, X-ray diffraction measurements using the out-of-plane method tend to reflect the diffracted light from planes parallel to the surface of the crystallites in the sample.

[0037] The diffraction angle 2θ characteristics of a thin film, such as the first layer of the absorber film 5 described above, are not necessarily determined solely by the composition of the thin film. The film density, crystalline state, valence of constituent elements, bonding state, and crystallite orientation of the thin film also affect its various properties. For this reason, various conditions are adjusted when depositing the thin film by sputtering to ensure that the thin film has the desired properties. For example, a wide range of conditions are adjusted, including the pressure in the deposition chamber (deposition pressure), the power applied to the sputtering target, the positional relationship between the target and the substrate to be deposited, and the target formation conditions, to ensure that the thin film has the desired properties. Furthermore, these deposition conditions are specific to the deposition apparatus and are adjusted as appropriate to ensure that the thin film has the desired properties. In addition, changes in the pattern dimensions formed on the thin film due to heating and cooling cannot necessarily be resolved by simply adjusting the characteristics of the thin film that are not affected by elements other than the thin film itself, such as the composition of the thin film. This is because, for example, the interaction between the thin film and a film formed beneath it also complexly affects the changes in pattern dimensions. Therefore, conventionally, it was difficult to find an absorber film 5 that could keep the pattern dimension change within an acceptable range by simply adjusting only simple properties such as the composition of the absorber film 5. The present invention has an unprecedented advantage in that it makes it possible to easily select an absorber film 5 that can reduce the pattern dimension change by obtaining macroscopic information (the difference between the two diffraction angles 2θ mentioned above) from the X-ray diffraction analysis of the first layer when it is laminated with other films such as a multilayer reflective film, a protective film, or a layer other than the first layer of the absorber film 5, rather than the composition of the absorber film 5 itself.

[0038] Here, we will describe the case in which the absorber film 5 includes only the first layer. That is, we will describe one form of a mask blank comprising a substrate 1, a multilayer reflective film 3 formed on the substrate 1, and an absorber film 5 consisting of the first layer formed on the multilayer reflective film 3.

[0039] Reflective masks manufactured using reflective mask blanks undergo repeated heating and cooling processes, such as during the mask manufacturing process, mask cleaning during use, and exposure. In reflective mask blanks, large film stress can cause deformation of the resulting reflective mask, affecting exposure characteristics. Specifically, while repeated heating and cooling processes, such as during the mask manufacturing process, mask cleaning, and exposure, gradually relieve the film stress of the absorber film, if the absorber film of the reflective mask blank has large film stress, the change in film stress before and after heating and cooling can become too large. As a result, the pattern shape changes, the pattern dimensions change before and after heating and cooling, and ultimately the mask life decreases.

[0040] Furthermore, the change in the dimensions of the absorber film pattern (transfer pattern) before and after heating and cooling is thought to be influenced not only by the film stress of the absorber film in the reflective mask blank, but also by other properties of the absorber film that interact in complex ways (such as film density, crystallinity, valence of constituent elements, bonding state, and crystallite orientation). In addition, the change in the dimensions of the absorber film pattern due to heating and cooling is also complexly influenced by interactions between the absorber film and other layers or films. For this reason, it was difficult to select an absorber film that could reduce the change in pattern dimensions before and after heating and cooling using simple properties such as the film stress and composition of the absorber film alone, as in the past. As a result of various studies, the inventors have newly discovered that it is possible to easily select a preferred absorber film by defining the relationship between the diffraction angle 2θin of the highest intensity peak obtained by X-ray diffraction analysis using the in-plane method and the diffraction angle 2θout of the highest intensity peak obtained by X-ray diffraction analysis using the out-of-plane method for the absorber film 5 consisting of the first layer described above.

[0041] In this embodiment, the first layer is preferably, though not limited to, a tensile stress. This makes it possible to better reduce the change in the pattern shape of the absorber film 5 before and after heat treatment in the reflective mask.

[0042] The absorber film 5, consisting of the first layer described above, has a structure such that the diffraction angle 2θin of the highest intensity peak obtained by X-ray diffraction analysis using the in-plane method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by X-ray diffraction analysis using the out-of-plane method. As a result, even when repeated heating and cooling treatments such as mask washing and exposure occur during the mask manufacturing process and repeated use of the mask are performed, fluctuations in the film stress of the absorber film can be kept to a near-zero or acceptable level. Therefore, there is almost no change in the pattern shape, and as a result, changes in pattern dimensions can be kept within an acceptable range, which in turn can extend the life of the mask.

[0043] In this invention, the X-ray diffraction measurement using the out-of-plane method is a measurement using a 2θ / ω scan, in which X-rays are incident on the surface of the absorber film 5 at an incident angle ω and the diffraction angle 2θout is measured. The X-ray diffraction measurement using the in-plane method is a measurement using a 2θχ / φ scan, in which X-rays are incident on the surface of the absorber film 5 at an incident angle of 0.5° and the diffraction angle 2θin is measured. When the axis passing through the surface of the absorber film 5 placed at a predetermined measurement position and parallel to the surface of the absorber film 5 is defined as the θ axis, the 2θχ axis penetrates the absorber film 5 and is perpendicular to the θ axis. The φ axis is an axis perpendicular to the surface of the absorber film 5.

[0044] The following describes a specific measurement method for X-ray diffraction in the present invention. Using an X-ray diffractometer, 2θ / ω scan measurements and 2θχ / φ scan measurements were performed on the absorber film 5 described above. The measurement area (measurement point) was defined as one point within a 20 mm × 20 mm area including the center of the absorber film. The center of the absorber film refers to the intersection of the diagonals of the absorber film in a top view. It is preferable to set the measurement point at the center of the absorber film. A CuKα1 line (wavelength: 1.5405 Å) with an output of 45 kV-200 mA was used as the X-ray source. In the in-plane method, measurements were performed and data was obtained under conditions of a step size of 0.024° and a scan speed of 0.5° / min. In the out-of-plane method, measurements were performed and data was obtained under conditions of a step size of 0.01° and a scan speed of 0.5° / min. In both methods, the scan angle was in the range of 20° to 80°.

[0045] In the present invention, the first layer preferably has a crystallite size of 3 nm or more, more preferably 4 nm or more, even more preferably 6 nm or more, and particularly preferably 7 nm or more. By having a crystallite size of 3 nm or more, the durability of the absorber film 5 and the adhesion between the first layer and other films above or below it can be improved. Furthermore, by having a crystallite size of 3 nm or more, the etching rate of the first layer can be increased. By increasing the etching rate of the first layer, damage to other films (e.g., multilayer reflective film 3 or protective film 4) present below the first layer during etching can be suppressed. In addition, in order to reduce the surface roughness of the first layer and the absorber film 5 including the first layer, the crystallite size of the first layer is preferably 20 nm or less, more preferably 18 nm or less, and even more preferably 15 nm or less.

[0046] The method for calculating the crystallite size of the first layer in the present invention is as follows. The crystallite size D was calculated from the full width at half maximum (FMAX) β (rad) of the diffraction peak where the diffraction intensity is maximum in the diffraction angle 2θ range from 20 degrees to 90 degrees, using Scherrer's equation (Equation (1)) below. D=K·λ / (β·cos(u / 2)) ···(1) Here, K is the Scherrer constant of 0.9, and λ is the wavelength of X-rays (CuKα1) = 1.5405 Å.

[0047] Furthermore, u is obtained by fitting the diffraction spectrum within the range of diffraction angles 2θmax ± 2 (degrees) where the diffraction intensity is maximum within the range of diffraction angles 2θmax ± 2 (degrees) using the Gaussian function (Equation (2)) below, using the least squares method. The full width at half maximum β was calculated from σ obtained by this fitting.

[0048]

number

[0049] Then, the full width at half maximum β was calculated using the σ obtained from the above fitting, from the following equation (Equation (3)).

[0050]

number

[0051] The material for the absorber film 5 consisting of the first layer described above is not particularly limited, as long as it absorbs EUV light, can be processed by etching or the like, and has a high etching selectivity ratio compared to the multilayer reflective film 3 or the protective film 4. Preferably, the material for the absorber film 5 consisting of the first layer is dry etchable with a fluorine-based gas containing fluorine (F). In this embodiment, as a material having the above-described functions, at least one metal, an alloy containing two or more metals, or a compound thereof can preferably be used. In addition to the above-described metals or alloys, the absorber film 5 consisting of the first layer may also contain oxygen (O), nitrogen (N), carbon (C), boron (B), and / or hydrogen (H).

[0052] For example, an absorber film 5 consisting of the above first layer made of at least one metal, an alloy containing two or more metals, or a compound thereof, from among ruthenium (Ru), platinum (Pt), iridium (Ir), and tantalum (Ta) tends to have high film stress. Therefore, the effects of the present invention can be obtained more favorably in an absorber film 5 containing at least one of ruthenium (Ru), platinum (Pt), iridium (Ir), and tantalum (Ta).

[0053] In this embodiment, as specific materials for the absorber membrane 5 consisting of the first layer, for example, PtRu, PtRuB, PtRuTa, IrTa, PtTa, RuTa, RuW, TaNb, RuSi, PtSi, and materials containing nitrogen, oxygen, carbon, boron, hydrogen and / or noble gases can be preferably used.

[0054] Furthermore, the absorber film 5 consisting of the first layer, which uses at least one metal from the above-mentioned ruthenium (Ru), platinum (Pt), iridium (Ir), and tantalum (Ta), an alloy containing two or more metals, or a compound thereof, may also contain, to the extent that it does not impair the effects of the present invention, for example, palladium (Pd), silver (Ag), gold (Au), osmium (Os), tungsten (W), chromium (Cr), cobalt (Co), and manganese (Mn). It may include at least one metal selected from tin (Sn), vanadium (V), nickel (Ni), hafnium (Hf), iron (Fe), copper (Cu), tellurium (Te), zinc (Zn), magnesium (Mg), germanium (Ge), aluminum (Al), rhodium (Rh), molybdenum (Mo), niobium (Nb), titanium (Ti), zirconium (Zr), yttrium (Y), and silicon (Si).

[0055] In this embodiment, the crystal structure of the absorber film 5 consisting of the first layer is preferably a face-centered cubic lattice structure (fcc) or a hexagonal close-packed structure (hcp). This is because it is the structure with the highest density and results in a dense film. A higher density structure makes it easier to obtain the desired optical properties (for example, refractive index n and extinction coefficient k for EUV light).

[0056] In this embodiment, the absorber film 5 consisting of the first layer has a refractive index n of preferably 0.8 or higher, more preferably 0.85 or higher, and particularly preferably 0.87 or higher with respect to EUV light. Furthermore, the refractive index n of the absorber film 5 is preferably 1.1 or lower, more preferably 1.0 or lower, and particularly preferably 0.98 or lower. Furthermore, the absorber film 5 consisting of the first layer in this embodiment has an extinction coefficient k of EUV light, preferably 0.008 or more, more preferably 0.01 or more, and particularly preferably 0.015 or more. In addition, the extinction coefficient k of the absorber film 5 is preferably 0.08 or less, more preferably 0.07 or less, and particularly preferably 0.065 or less.

[0057] The thickness of the absorber film 5, which consists of the first layer described above, is preferably 10 nm or more. A thickness of 10 nm or more allows for appropriate stress, thereby better achieving the effects of the present invention. Furthermore, to reduce the shadowing effect and obtain an absorber film pattern with a good cross-sectional shape, the thickness of the absorber film 5 is preferably 100 nm or less. In particular, a thickness of the absorber film 5 in the range of approximately 20 nm to 70 nm is preferred. The film deposition method is not particularly limited, but typically, magnetron sputtering or ion beam sputtering is preferred.

[0058] The above description concerns the case where the absorber film 5 includes only the first layer. However, the absorber film 5 can also be configured as a laminated film consisting of the first layer as an upper layer and a lower layer provided below the first layer, made of materials with different etching selectivity. In this case, the lower layer is preferably a buffer layer provided on the multilayer reflective film 3 or the protective film 4 in a configuration having the multilayer reflective film 3 or the protective film 4. When manufacturing a reflective mask using a reflective mask blank, there is a possibility of damaging the multilayer reflective film 3 or the protective film 4 when etching the absorber film 5. By making the lower layer a buffer layer, damage to the surface of the multilayer reflective film 3 or the protective film 4 when etching the first layer as the upper layer of the absorber film 5 can be suppressed.

[0059] In this embodiment, as described above, the first layer is preferably formed of a material that can be dry-etched with a fluorine-based gas containing fluorine (F). For this reason, in this case, the material of the buffer layer which is the lower layer is preferably a material that has etching resistance to fluorine-based etching gases, for example, a material that can be etched using a chlorine-based etching gas. Accordingly, as the material of the lower layer of the absorber film 5, examples include chromium-based materials, tantalum-based materials, and ruthenium-based materials, and materials that further include at least one selected from O, N, C, and B.

[0060] In a configuration where the absorber film 5 is a laminated film consisting of a first layer as an upper layer and a lower layer provided below the first layer, each made of materials with different etching selectivity, it is preferable that the first layer has a crystallite size of 3 nm or more, and it is also preferable that the first layer has a crystallite size that is 2 nm or more larger than the crystallite size of the lower layer provided below the first layer.

[0061] Even in a configuration where the absorber film 5 is a laminated film consisting of a first layer as an upper layer and a lower layer provided below the first layer, each made of materials with different etching selectivity, the etching rate of the first layer can be increased by having a crystallite size of 3 nm or more. By increasing the etching rate of the first layer, damage to the lower layer (for example, the buffer layer) located below the first layer during etching can be suppressed. In order to reduce the surface roughness of the first layer and the absorber film 5 including the first layer, the crystallite size of the first layer is preferably 20 nm or less, and more preferably 15 nm or less.

[0062] Furthermore, it is more preferable that the difference between the crystallite size of the first layer and the crystallite size of the lower layer is 2 nm or more. By having a crystallite size of 2 nm or more that is larger than the crystallite size of the lower layer provided beneath the first layer, the adhesion between the upper layer (first layer) and the lower layer can be improved. The lower layer preferably has a crystallite size of 1.5 nm or less, more preferably 1.0 nm or less, and particularly preferably has an amorphous structure. This makes it possible to reduce the surface roughness of the absorber film 5 even if the crystallite size of the first layer is, for example, 3 nm or more. There is no particular upper limit to the difference in crystallite sizes, but it can be, for example, 20 nm or less, preferably 18 nm or less, and more preferably 15 nm or less.

[0063] Even in a configuration where the absorber film 5 is a laminated film consisting of a first layer as an upper layer and a lower layer provided below the first layer, each made of materials with different etching selectivity, the thickness of the first layer is preferably, for example, 10 nm or more, more preferably 15 nm or more, and particularly preferably 20 nm or more. By having a thickness of 10 nm or more for the first layer, the absorber film 5 can sufficiently absorb EUV light and have appropriate stress. In order to reduce the shadowing effect and obtain an absorber film pattern with a good cross-sectional shape, the thickness of the first layer is preferably, for example, 100 nm or less. In particular, a thickness of the first layer in the range of about 20 nm to 70 nm is preferred.

[0064] Furthermore, in the absorbent film 5, it is preferable that the first layer has the largest film thickness. In this case, the ratio of the film thickness of the first layer to the film thickness of the absorbent film 5 is preferably 0.5 or more, more preferably 0.7 or more, and particularly preferably 0.8 or more. The ratio of the film thickness of the first layer to the film thickness of the absorbent film 5 is preferably 0.99 or less, more preferably 0.98 or less, and particularly preferably 0.97 or less. By having the ratio of the film thickness of the first layer to the film thickness of the absorbent film 5 within the above range, it is possible to obtain a better reflective mask blank and a reflective mask for manufacturing a reflective mask that can keep the change in pattern dimensions within an acceptable range even after repeated heating and cooling treatments.

[0065] Furthermore, the method for depositing the lower layer (for example, the buffer layer) is not particularly limited, but magnetron sputtering or ion beam sputtering is generally preferred.

[0066] The absorber film 5 described above may consist of a single layer or two layers (upper and lower layers), or it may consist of three or more layers. When the absorber film 5 has three or more layers, it is preferable that the layer with the largest film thickness is the first layer. For example, the absorber film 5 may consist of the lower layer (e.g., a buffer layer), an upper layer as the first layer, and an uppermost layer provided on top of the upper layer. The uppermost layer may be made of a different material from the upper layer, or it may be made of a material containing the same constituent elements as the upper layer but in different compositional ratios. The uppermost layer may also be made of a material with a higher oxygen content than the upper layer. The specific material of the uppermost layer may be any of the materials exemplified above for the upper and lower layers. The method for depositing the uppermost layer is not particularly limited, but magnetron sputtering or ion beam sputtering is usually preferred. Both the uppermost layer and the lower layer may contain multiple layers.

[0067] Next, the conductive film 2 on the back surface will be described. The above-mentioned back surface conductive film 2 can consist of a single layer. This simplifies the film formation process. Alternatively, the above-mentioned back surface conductive film 2 may be a laminated film containing multiple layers. In this case, for example, the oxygen content of the uppermost layer of the laminated film can be made higher than that of the other layers. That is, the uppermost layer can be made the layer with the highest oxygen content. This further suppresses particle generation when the electrostatic chuck is detached. It is preferable that this uppermost layer has a wavelength of, for example, 2 nm or more.

[0068] The thickness of the conductive film 2 on the back surface is not particularly limited, but is preferably 10 nm or more, and more preferably 20 nm or more. Furthermore, the thickness is preferably 500 nm or less, more preferably 200 nm or less, and even more preferably 100 nm or less. The method for depositing the conductive film 2 on the back surface is not particularly limited, but is usually preferably magnetron sputtering or ion beam sputtering.

[0069] The material of the conductive film 2 on the back surface is not particularly limited, but tantalum-based materials and chromium-based materials are preferred, for example. Examples of tantalum-based materials include elemental tantalum (Ta), or materials containing tantalum and one or more elements selected from carbon (C), nitrogen (N), oxygen (O), boron (B), hydrogen (H), etc. Furthermore, chromium-based materials include elemental chromium (Cr), or materials containing chromium and one or more elements selected from carbon (C), nitrogen (N), oxygen (O), boron (B), hydrogen (H), etc.

[0070] In particular, since the above-mentioned tantalum-based material has high cleaning resistance, it is preferable in the present invention that the back surface conductive film 2 is made of a tantalum-based material. Furthermore, from the viewpoint of chemical resistance and abrasion resistance, it is even more preferable that the metal contained in the back surface conductive film 2 is tantalum only.

[0071] When the above-mentioned back surface conductive film 2 is made of a tantalum-based material, specific examples include TaN, TaB, and TaBN. When the above-mentioned back surface conductive film 2 contains tantalum, its content is preferably 40 atomic percent or more. Furthermore, when the above-mentioned conductive film 2 contains tantalum and nitrogen, the total content of tantalum and nitrogen is preferably 95 atomic percent or more.

[0072] Furthermore, it is preferable that the back surface conductive film 2 has compressive stress. Having compressive stress in the back surface conductive film 2 effectively reduces the warping of the substrate 1 caused by the multilayer reflective film 3.

[0073] <Second Embodiment> Figure 2 is a schematic cross-sectional view showing another embodiment (second embodiment) of the reflective mask blank of the present invention. Figure 2 shows a reflective mask blank 10B of the second embodiment. The reflective mask blank 10B comprises a substrate 1, a multilayer reflective film 3 formed on the substrate 1, a protective film 4 formed on the multilayer reflective film 3, and an absorber film 5 formed on the protective film 4. The reflective mask blank 10B has a back surface conductive film 2 on the back surface of the substrate 1. The reflective mask blank 10B of this embodiment differs from the reflective mask blank 10A of the first embodiment in that the protective film 4 is formed between the multilayer reflective film 3 and the absorber film 5.

[0074] The protective film 4 described above will now be explained. Typically, a protective film 4 (capping layer) can be provided on the multilayer reflective film 3 for the purpose of protecting it during patterning or pattern modification of the absorber film 5. Such a protective film 4 is formed from a material mainly composed of ruthenium. Examples of materials mainly composed of ruthenium include elemental Ru metal, Ru alloys containing Ru with at least one metal selected from titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), zirconium (Zr), yttrium (Y), boron (B), lanthanum (La), cobalt (Co), chromium (Cr), and rhenium (Re), and materials containing nitrogen. The protective film 4 can also be formed from a material mainly composed of rhodium instead of ruthenium. "Mainly composed of element X" means containing 50 atomic percent or more of element X. Furthermore, the thickness of the protective film 4 is not particularly limited, but a range of approximately 1 nm to 5 nm is preferred.

[0075] Furthermore, the components of the reflective mask blank 10B of this embodiment, other than the protective film 4, are the same as those in the reflective mask blank 10A of the first embodiment described above, and the details of their configurations are also as described in the reflective mask blank 10A of the first embodiment described above. Furthermore, in the reflective mask blank 10B of this embodiment, the absorber film 5 includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis using the in-plane X-ray diffraction method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis using the out-of-plane X-ray diffraction method.

[0076] Therefore, even when the reflective mask blank 10B of this embodiment undergoes repeated heating and cooling processes such as mask manufacturing, mask cleaning, and exposure, the fluctuation in the film stress of the absorber film is almost nonexistent or small enough to be acceptable. As a result, there is almost no change in the pattern shape, and consequently, changes in the pattern dimensions can be kept within an acceptable range, which in turn extends the lifespan of the mask.

[0077] <Third Embodiment> Figure 3 is a schematic cross-sectional view showing another embodiment (third embodiment) of the reflective mask blank of the present invention. As shown in Figure 3, the reflective mask blank 10C of the third embodiment comprises a substrate 1, a multilayer reflective film 3 formed on the substrate 1, a protective film 4 formed on the multilayer reflective film 3, an absorber film 5 formed on the protective film 4, and an etching mask film 6 formed on the absorber film 5. The reflective mask blank 10C of the third embodiment has a back surface conductive film 2 on the back surface of the substrate 1. The reflective mask blank 10C of this embodiment differs from the reflective mask blank 10B of the second embodiment in that the etching mask film 6 is formed on the absorber film 5.

[0078] The etching mask film 6 described above will now be explained. The reflective mask blank 10C of this embodiment is provided with an etching mask film 6 on the absorber film 5. This etching mask film 6 functions as a mask when patterning the absorber film 5. The etching mask film 6 is made of a material with different etching selectivity from the material of the uppermost layer (e.g., the first layer or top layer) of the absorber film 5. For example, if the first layer or top layer of the absorber film 5 is made of a material containing at least one of the aforementioned ruthenium, platinum, iridium, and tantalum, the etching mask film 6 can be made of a chromium-based material, a tantalum-based material, or a silicon-based material such as silicon or a silicon compound. Examples of chromium-based materials include elemental Cr, and materials containing Cr and at least one element selected from N, O, C, and H. Examples of tantalum-based materials include elemental Ta, and materials containing Ta and at least one element selected from N, O, C, H, and B. Examples of silicon compounds include materials containing Si and at least one element selected from N, O, C, and H, as well as materials such as metallic silicon (metallic silicide) and metallic silicon compounds (metallic silicide compounds) that contain metal in silicon compounds. Examples of metallic silicon compounds include materials containing a metal and at least one element selected from N, O, C, and H.

[0079] The etching mask film 6 described above can consist of a single layer or a multilayer film comprising multiple layers. When the etching mask film 6 comprises multiple layers, multiple layers of the same material may be stacked, or multiple layers of different materials may be stacked. The material of each of the multiple layers is not particularly limited, but can be selected from the chromium-based material, tantalum-based material, and silicon-based compound described above.

[0080] Furthermore, regarding the components of the reflective mask blank 10C of this embodiment, other than the etching mask film 6, the substrate 1, the underlayer (not shown), the multilayer reflective film 3, the protective film 4, the absorber film 5, and the back surface conductive film 2 are all the same as those in the reflective mask blank 10A of the first embodiment or the reflective mask blank 10B of the second embodiment described above, and the details of their configurations are also as described in the reflective mask blank 10A of the first embodiment or the reflective mask blank 10B of the second embodiment described above. Furthermore, in the reflective mask blank 10C of this embodiment, the absorber film 5 includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis using the in-plane X-ray diffraction method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis using the out-of-plane X-ray diffraction method.

[0081] Therefore, even when the reflective mask blank 10C of this embodiment undergoes repeated heating and cooling processes such as mask manufacturing, mask cleaning, and exposure, the fluctuation in the film stress of the absorber film is almost nonexistent or small enough to be acceptable. As a result, there is almost no change in the pattern shape, and consequently, changes in the pattern dimensions can be kept within an acceptable range, which in turn extends the lifespan of the mask.

[0082] The reflective mask blank of the present invention has been described above with reference to the first to third embodiments. Reflective masks manufactured from the reflective mask blank of the present invention exhibit almost no or tolerable fluctuations in the film stress of the absorber film even after repeated heating and cooling treatments such as the mask manufacturing process, mask washing, and exposure. As a result, there is almost no change in the pattern shape, and consequently, changes in pattern dimensions can be kept within an acceptable range, thereby extending the lifespan of the mask.

[0083] [Reflective mask] Next, the reflective mask of the present invention will be described. Figure 4 is a schematic cross-sectional view showing one embodiment of the reflective mask of the present invention. A reflective mask 20 according to one embodiment of the present invention is manufactured, for example, using the reflective mask blank described above. As shown in Figure 4, the reflective mask 20 according to this embodiment comprises a substrate 1, a multilayer reflective film 3 formed on the substrate 1, a protective film 4 formed on the multilayer reflective film 3, and an absorber film formed on the protective film 4 on which a transfer pattern 5a is formed. The reflective mask 20 according to this embodiment has a back surface conductive film 2 on the back surface of the substrate 1. In the reflective mask 20 of this embodiment as well, the absorber film on which the transfer pattern 5a is formed includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis by X-ray diffraction using the in-plane method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis by X-ray diffraction using the out-of-plane method.

[0084] The components of the reflective mask 20 of this embodiment—the substrate 1, the underlayer (not shown), the multilayer reflective film 3, the protective film 4, the absorber film 5a, and the back surface conductive film 2—are all the same as those in the reflective mask blank 10A of the first embodiment or the reflective mask blank 10B of the second embodiment described above, and the details of their configurations are also as described in the reflective mask blank 10A of the first embodiment or the reflective mask blank 10B of the second embodiment described above.

[0085] Next, a method for manufacturing the reflective mask 20 of this embodiment will be described. First, for example, an electron beam lithography resist is applied to the reflective mask blank 10C described above and baked to form a resist film. A drawing is performed on the resist film using an electron beam lithography apparatus. The resist film after drawing is developed. In this way, a predetermined resist pattern is formed on the resist film.

[0086] Subsequently, the etching mask film 6 is patterned by dry etching using the above resist pattern as a mask.

[0087] Next, the absorber film 5 is patterned by dry etching using the patterned etching mask film 6 as a mask to form an absorber film pattern. Here, if the absorber film 5 has a laminated structure of the first layer and a lower layer provided below the first layer, the first layer, which is the upper layer of the absorber film 5, is dry etched using, for example, a fluorine-based gas, using the patterned etching mask film 6 as a mask. This forms the first layer pattern. Furthermore, the lower layer is patterned using the first layer pattern as a mask. If the absorber film 5 has three or more layers, each layer can be etched using an etching gas suitable for the material of each layer of the absorber film 5. This forms a predetermined transfer pattern 5a (see Figure 4) on the absorber membrane 5. The remaining resist pattern is removed either before or after the patterning process of the absorber film 5. Finally, the unnecessary patterned etching mask film 6 is removed as needed to create the reflective mask 20 (see Figure 4).

[0088] [Manufacturing method for semiconductor devices] This invention also provides a method for manufacturing a semiconductor device using a reflective mask. In other words, the present invention provides a method for manufacturing a semiconductor device, which includes using the reflective mask described above and exposing and transferring the transfer pattern of the reflective mask onto a transfer target on a semiconductor substrate.

[0089] Reflective masks manufactured from the reflective mask blank of the present invention exhibit virtually no or acceptable fluctuations in the film stress of the absorber film, even after repeated heating and cooling treatments such as mask manufacturing processes, mask washing, and exposure. As a result, there is almost no change in the pattern shape, and consequently, changes in pattern dimensions can be kept within an acceptable range, thereby extending the mask's lifespan. Therefore, according to the method for manufacturing a semiconductor device using the reflective mask of the present invention, high-precision pattern transfer can be performed, and a high-quality semiconductor device with few defects can be manufactured. [Examples]

[0090] The embodiments of the present invention will be described in more detail below with reference to examples. (Example 1) A 6-inch square SiO2-TiO2 glass substrate, approximately 152.0 mm x 152.0 mm in size and 6.35 mm thick, was prepared. The glass substrate was polished stepwise using a double-sided polishing apparatus with cerium oxide abrasive grains and colloidal silica abrasive grains. The surface of the polished glass substrate was treated with a low concentration of hydrofluoric acid. The resulting glass substrate (substrate 1) had a smooth surface with a root mean square roughness (Rq) of 0.25 nm and a flatness of 100 nm or less. Surface roughness was measured using an atomic force microscope (AFM), with a measurement area of ​​1 μm x 1 μm.

[0091] First, a tantalum Ta conductive film was formed on the back surface of the glass substrate. The substrate was placed in a sputtering apparatus, and a 70 nm thick Ta film was formed by sputtering using a tantalum (Ta) target and xenon (Xe) gas as the sputtering gas.

[0092] Next, on the main surface of the glass substrate opposite the conductive film, a multilayer reflective film was formed by stacking Si films (thickness: 4.0 nm) and Mo films (thickness: 3.1 nm) in 40 cycles, with each cycle consisting of a Si film and a Mo film (thickness: 3.3 nm), and finally forming a Si film (thickness: 3.3 nm) on top of that. Furthermore, a protective film made of Ru (thickness: 3.5 nm) was deposited on top of that to obtain a substrate with a multilayer reflective film.

[0093] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and a PtRuN film (film thickness: 30 nm) as the upper layer in that order. The deposition conditions and composition ratios for the CrN film and PtRuN film are shown below. CrN film Composition ratio Cr:N=90at%:10at% Target: Cr target Sputtering gas (flow ratio): Argon (90%) and nitrogen (10%) PtRuN film Composition ratio Pt:Ru:N=56at%:42at%:2at% Targets: Pt target and Ru target Sputtering gas (flow ratio): Argon (13%), Xenon (32%), and Nitrogen (55%) Deposition pressure: 0.13 Pa

[0094] X-ray diffraction measurements were performed on the PtRuN film on top of the formed absorber film using both the in-plane and out-of-plane methods. The details of the X-ray diffraction measurements were as described above.

[0095] In the X-ray diffraction analysis using the in-plane method, the diffraction angle 2θin of the highest intensity peak was 39.9 degrees. In the X-ray diffraction analysis using the out-of-plane method, the diffraction angle 2θout of the highest intensity peak was 40.3 degrees. Therefore, in this example, the absorber film contained a layer having a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. In Example 1, the thickness of the PtRuN film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is thought that the results of the X-ray diffraction analysis above reflect the characteristics of the PtRuN film. For this reason, the PtRuN film can be considered to be the first layer.

[0096] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite the conductive film. Subsequently, an etching mask film (thickness: 16 nm) made of CrN film was deposited on the absorber film using a DC magnetron sputtering apparatus. As described above, the reflective mask blank of Example 1 was fabricated.

[0097] Next, a reflective mask was fabricated using this reflective mask blank, following the manufacturing method described above. First, an electron beam resist was applied to the aforementioned reflective mask blank and baked to form a resist film. An electron beam lithography system was used to draw patterns on the resist film. The resist film was then developed. In this way, a predetermined resist pattern was formed on the resist film.

[0098] Subsequently, the above resist pattern was used as a mask, and the etching mask film was patterned by dry etching using a chlorine-based gas.

[0099] Next, the remaining resist pattern was removed. Using the patterned etching mask film as a mask, the upper PtRuN film of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the lower CrN film was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a transfer pattern with a width (dimension) of 50 nm on the absorber film. Hereafter, the transfer pattern will simply be referred to as the pattern. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). Thus, a reflective mask was fabricated (see Figure 4 above).

[0100] The obtained reflective mask was heated at 150°C for 30 minutes and then cooled to 25°C in air. This heating and cooling process was performed for 10 consecutive cycles, with each cycle counting as one. The change in pattern width (dimension) after 10 cycles of this heating and cooling process was calculated as the difference between the pattern width after 10 cycles and the pattern width before the heating and cooling process. The pattern width was measured by acquiring a cross-sectional image of the pattern using a scanning transmission electron microscope. As a result, the change in pattern width was 0.5 nm, which was within the acceptable range. In other words, the reflective mask obtained in this embodiment showed acceptable fluctuations in the film stress of the absorber film even after repeated heating and cooling processes. Therefore, there was almost no change in the pattern shape, and as a result, the change in pattern dimensions was kept within the acceptable range.

[0101] The resulting reflective mask was then placed in an exposure apparatus, and the pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the transferred pattern was free of defects, and a good pattern transfer was achieved.

[0102] (Example 2) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0103] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and a PtRuB film (film thickness: 30 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the PtRuB film are shown below. PtRuB film Composition ratio Pt:Ru:B=32at%:60at%:8at% Targets: Pt targets and RuB targets Sputtering gas (flow ratio): Argon (55%) and Krypton (45%) Deposition pressure: 0.13 Pa

[0104] The PtRuB film on top of the formed absorber film was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1.

[0105] In the X-ray diffraction analysis using the in-plane method, the diffraction angle 2θin of the highest intensity peak was 40.1 degrees. In the X-ray diffraction analysis using the out-of-plane method, the diffraction angle 2θout of the highest intensity peak was 40.5 degrees. Therefore, in this example, the absorber film contained a layer having a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. In Example 2, the thickness of the PtRuB film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is thought that the results of the X-ray diffraction analysis above reflect the characteristics of the PtRuB film. For this reason, the PtRuB film can be considered to be the first layer.

[0106] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, the reflective mask blank of Example 2 was fabricated.

[0107] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the upper PtRuB film of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the lower CrN film was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0108] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 0.5 nm, which was within the acceptable range. In other words, the reflective mask obtained in this example showed that even after repeated heating and cooling treatments, the fluctuation in the film stress of the absorber film was small enough to be acceptable. As a result, there was almost no change in the shape of the pattern, and consequently, the change in pattern dimensions was kept within the acceptable range.

[0109] The resulting reflective mask was then placed in an exposure apparatus, and the pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the transferred pattern was free of defects, and a good pattern transfer was achieved.

[0110] (Example 3) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0111] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and an IrTa film (film thickness: 40 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the IrTa film are shown below. IrTa film Composition ratio Ir:Ta=75at%:25at% Targets: Ir target and Ta target Sputtering gas (flow ratio): Xenon (100%) Deposition pressure: 0.15 Pa

[0112] The IrTa film on top of the formed absorber film was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1.

[0113] In the analysis using the in-plane X-ray diffraction method, the diffraction angle 2θin of the highest intensity peak was 40.2 degrees. In the analysis using the out-of-plane X-ray diffraction method, the diffraction angle 2θout of the highest intensity peak was 40.4 degrees. Therefore, in this example, the absorber film contained a layer having a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. In Example 3, the thickness of the IrTa film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is thought that the results of the above X-ray diffraction analysis reflect the characteristics of the IrTa film. For this reason, the IrTa film can be considered to be the first layer.

[0114] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, the reflective mask blank of Example 3 was fabricated.

[0115] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the upper IrTa film of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the lower CrN film was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0116] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 0.5 nm, which was within the acceptable range. In other words, the reflective mask obtained in this example showed that even after repeated heating and cooling treatments, the fluctuation in the film stress of the absorber film was small enough to be acceptable. As a result, there was almost no change in the shape of the pattern, and consequently, the change in pattern dimensions was kept within the acceptable range.

[0117] The resulting reflective mask was then placed in an exposure apparatus, and the pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the transferred pattern was free of defects, and a good pattern transfer was achieved.

[0118] (Example 4) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0119] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and a PtRuTaN film (film thickness: 30 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the PtRuTaN film are shown below. PtRuTaN film Composition ratio Pt:Ru:Ta:N=43at%:40at%:10at%:7at% Targets: PtTa target and Ru target Sputtering gas (flow ratio): Xenon (43%) and nitrogen (57%) Deposition pressure: 0.13 Pa

[0120] The PtRuTaN film on top of the formed absorber film was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1.

[0121] In the X-ray diffraction analysis using the in-plane method, the diffraction angle 2θin of the highest intensity peak was 39.7 degrees, and in the X-ray diffraction analysis using the out-of-plane method, the diffraction angle 2θout of the highest intensity peak was 39.9 degrees. Therefore, in this example, the absorber film contained a layer having a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. In Example 4, the thickness of the PtRuTaN film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is thought that the results of the X-ray diffraction analysis above reflect the characteristics of the PtRuTaN film. For this reason, the PtRuTaN film can be considered to be the first layer.

[0122] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, the reflective mask blank of Example 4 was fabricated.

[0123] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the upper PtRuTaN film of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the lower CrN film was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0124] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 0.5 nm, which was within the acceptable range. In other words, the reflective mask obtained in this example showed that even after repeated heating and cooling treatments, the fluctuation in the film stress of the absorber film was small enough to be acceptable. As a result, there was almost no change in the shape of the pattern, and consequently, the change in pattern dimensions was kept within the acceptable range.

[0125] The resulting reflective mask was then placed in an exposure apparatus, and the pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the transferred pattern was free of defects, and a good pattern transfer was achieved.

[0126] (Example 5) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0127] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and a PtTaN film (film thickness: 30 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the PtTaN film are shown below. PtTaN film Composition ratio Pt:Ta:N=73at%:21at%:6at% Targets: Pt targets and Ta targets Sputtering gas (flow ratio): Krypton (43%) and nitrogen (57%) Deposition pressure: 0.13 Pa

[0128] The PtTaN film on top of the formed absorber film was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1.

[0129] In the X-ray diffraction analysis using the in-plane method, the diffraction angle 2θin of the highest intensity peak was 39.0 degrees. In the X-ray diffraction analysis using the out-of-plane method, the diffraction angle 2θout of the highest intensity peak was 39.4 degrees. Therefore, in this example, the absorber film contained a layer having a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. In Example 5, the thickness of the PtTaN film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is considered that the results of the X-ray diffraction analysis above reflect the characteristics of the PtTaN film. For this reason, the PtTaN film can be considered to be the first layer.

[0130] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, the reflective mask blank of Example 5 was fabricated.

[0131] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the upper PtTaN film of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the lower CrN film was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0132] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 0.5 nm, which was within the acceptable range. In other words, the reflective mask obtained in this example showed that even after repeated heating and cooling treatments, the fluctuation in the film stress of the absorber film was small enough to be acceptable. As a result, there was almost no change in the shape of the pattern, and consequently, the change in pattern dimensions was kept within the acceptable range.

[0133] The resulting reflective mask was then placed in an exposure apparatus, and the pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the transferred pattern was free of defects, and a good pattern transfer was achieved.

[0134] (Example 6) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0135] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and a RuTa film (film thickness: 40 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the RuTa film are shown below. RuTa membrane Composition ratio Ru:Ta=45at%:55at% Targets: Ru target and Ta target Sputtering gas (flow ratio): Xenon (100%) Deposition pressure: 0.13 Pa

[0136] The RuTa film on top of the formed absorber film was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1.

[0137] In the analysis results by X-ray diffraction using the in-plane method, the diffraction angle 2θin of the highest intensity peak was 39.6 degrees. In the analysis results by X-ray diffraction using the out-of-plane method, the diffraction angle 2θout of the highest intensity peak was 39.9 degrees. Therefore, in this example, the absorber film contained a layer having a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. In Example 6, the thickness of the RuTa film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is thought that the results of the above X-ray diffraction analysis reflect the characteristics of the RuTa film. For this reason, the RuTa film can be considered to be the first layer.

[0138] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, the reflective mask blank of Example 6 was fabricated.

[0139] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the RuTa film on the upper layer of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the CrN film on the lower layer was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0140] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 0.5 nm, which was within the acceptable range. In other words, the reflective mask obtained in this example showed that even after repeated heating and cooling treatments, the fluctuation in the film stress of the absorber film was small enough to be acceptable. As a result, there was almost no change in the shape of the pattern, and consequently, the change in pattern dimensions was kept within the acceptable range.

[0141] The resulting reflective mask was then placed in an exposure apparatus, and the pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the transferred pattern was free of defects, and a good pattern transfer was achieved.

[0142] (Example 7) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0143] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and a RuW film (film thickness: 40 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the RuW film are shown below. RuW membrane Composition ratio Ru:W=25at%:75at% Targets: Ru target and W target Sputtering gas (flow ratio): Xenon (100%) Deposition pressure: 0.13 Pa

[0144] The RuW film on top of the formed absorber film was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1.

[0145] In the analysis using the in-plane X-ray diffraction method, the diffraction angle 2θin of the highest intensity peak was 35.5 degrees. In the analysis using the out-of-plane X-ray diffraction method, the diffraction angle 2θout of the highest intensity peak was 35.7 degrees. Therefore, in this embodiment, the absorber film contained a layer having a structure in which the diffraction angle 2θin was 2θout or less. In Example 7, the thickness of the RuW film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is considered that the results of the above X-ray diffraction analysis reflect the characteristics of the RuW film. For this reason, the RuW film can be considered to be the first layer.

[0146] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, the reflective mask blank of Example 7 was fabricated.

[0147] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the RuW film on the upper layer of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the CrN film on the lower layer was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0148] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 0.5 nm, which was within the acceptable range. In other words, the reflective mask obtained in this example showed that even after repeated heating and cooling treatments, the fluctuation in the film stress of the absorber film was small enough to be acceptable. As a result, there was almost no change in the shape of the pattern, and consequently, the change in pattern dimensions was kept within the acceptable range.

[0149] The resulting reflective mask was then placed in an exposure apparatus, and the pattern was transferred onto a semiconductor substrate on which a resist film had been formed. As a result, the transferred pattern was free of defects, and a good pattern transfer was achieved.

[0150] (Comparative Example 1) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0151] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and a PtRuN film (film thickness: 30 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the PtRuN film are shown below. PtRuN film Composition ratio Pt:Ru:N=52at%:44at%:4at% Targets: Pt target and Ru target Sputtering gas (flow ratio): Xenon (3%) and nitrogen (97%) Deposition pressure: 0.29 Pa

[0152] The PtRuN film on the upper layer of the absorber film formed above was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1. In Comparative Example 1, the thickness of the PtRuN film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is considered that the results of the X-ray diffraction analysis below reflect the characteristics of the PtRuN film.

[0153] In-plane X-ray diffraction analysis showed that the diffraction angle 2θin of the highest intensity peak was 39.3 degrees. Out-of-plane X-ray diffraction analysis showed that the diffraction angle 2θout of the highest intensity peak was 37.9 degrees. Therefore, in this comparative example, the diffraction angle 2θin of the absorber film was greater than the diffraction angle 2θout. In other words, the absorber film of Comparative Example 1 did not have a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. The PtRuN film of Comparative Example 1 had almost the same composition as the PtRuN film of Example 1, but contrary to Example 1, the diffraction angle 2θin of the PtRuN film of Comparative Example 1 was greater than the diffraction angle 2θout. From this, it became clear that the relationship between the two diffraction angles (2θin and 2θout) does not depend on the composition of the film.

[0154] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, a reflective mask blank for Comparative Example 1 was prepared.

[0155] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the upper PtRuN film of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the lower CrN film was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0156] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 3 nm, which exceeded the acceptable range. In other words, it was found that the reflective mask obtained in this comparative example underwent a large fluctuation in the film stress of the absorber film when subjected to repeated heating and cooling treatments. Therefore, it was not possible to keep the changes in pattern shape and pattern dimensions within the acceptable range.

[0157] (Comparative Example 2) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0158] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and an IrTa film (film thickness: 40 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the IrTa film are shown below. IrTa film Composition ratio Ir:Ta=75at%:25at% Targets: Ir target and Ta target Sputtering gas (flow ratio): Argon (100%) Deposition pressure: 0.17 Pa

[0159] The IrTa film on the upper layer of the absorber film formed above was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1. In Comparative Example 2, the thickness of the IrTa film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is considered that the results of the above X-ray diffraction analysis reflect the characteristics of the IrTa film.

[0160] In-plane X-ray diffraction analysis showed that the diffraction angle 2θin of the highest intensity peak was 40.6 degrees. Out-of-plane X-ray diffraction analysis showed that the diffraction angle 2θout of the highest intensity peak was 40.1 degrees. Therefore, in this comparative example, the diffraction angle 2θin of the absorber film was greater than the diffraction angle 2θout. In other words, the absorber film of Comparative Example 2 did not have a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. The IrTa film of Comparative Example 2 had the same composition as the IrTa film of Example 3, but contrary to Example 3, the diffraction angle 2θin of the IrTa film of Comparative Example 2 was greater than the diffraction angle 2θout. From this, it became clear that the relationship between the two diffraction angles (2θin and 2θout) is independent of the film composition.

[0161] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, a reflective mask blank for Comparative Example 2 was prepared.

[0162] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the upper IrTa film of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the lower CrN film was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0163] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 4 nm, which exceeded the acceptable range. In other words, it was found that the reflective mask obtained in this comparative example underwent a large fluctuation in the film stress of the absorber film when subjected to repeated heating and cooling treatments. Therefore, it was not possible to keep the changes in pattern shape and pattern dimensions within the acceptable range.

[0164] (Comparative Example 3) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0165] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) and a PtTa film (film thickness: 30 nm) in that order as the underlying layers. The composition ratio and deposition conditions for the CrN film were the same as those in Example 1. The deposition conditions and composition ratio for the PtTa film are shown below. PtTa film Composition ratio Pt:Ta=64at%:36at% Targets: Pt targets and Ta targets Sputtering gas (flow ratio): Xenon (100%) Deposition pressure: 0.13 Pa

[0166] X-ray diffraction measurements using the in-plane method and the out-of-plane method were performed on the PtTa film on the upper layer of the absorber film formed above, in the same manner as in Example 1. In Comparative Example 3, the thickness of the PtTa (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is considered that the results of the above X-ray diffraction analysis reflect the characteristics of the PtTa film.

[0167] In-plane X-ray diffraction analysis showed that the diffraction angle 2θin of the highest intensity peak was 39.1 degrees. Out-of-plane X-ray diffraction analysis showed that the diffraction angle 2θout of the highest intensity peak was 38.8 degrees. Therefore, in this comparative example, the above absorber film had a diffraction angle 2θin greater than the diffraction angle 2θout. In other words, the absorber film of Comparative Example 3 did not have a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout.

[0168] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, a reflective mask blank for Comparative Example 3 was prepared.

[0169] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the upper PtTa film of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the lower CrN film was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0170] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 3 nm, which exceeded the acceptable range. In other words, it was found that the reflective mask obtained in this comparative example underwent a large fluctuation in the film stress of the absorber film when subjected to repeated heating and cooling treatments. Therefore, it was not possible to keep the changes in pattern shape and pattern dimensions within the acceptable range.

[0171] (Comparative Example 4) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0172] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and a RuTa film (film thickness: 40 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the RuTa film are shown below. RuTa membrane Composition ratio Ru:Ta=50at%:50at% Targets: Ru target and Ta target Sputtering gas (flow ratio): Argon (100%) Deposition pressure: 0.15 Pa

[0173] The RuTa film on the upper layer of the absorber film formed above was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1. In Comparative Example 4, the thickness of the RuTa film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is considered that the results of the above X-ray diffraction analysis reflect the characteristics of the RuTa film.

[0174] In-plane X-ray diffraction analysis showed that the diffraction angle 2θin of the highest intensity peak was 40.1 degrees. Out-of-plane X-ray diffraction analysis showed that the diffraction angle 2θout of the highest intensity peak was 39.8 degrees. Therefore, in this comparative example, the diffraction angle 2θin of the absorber film was greater than the diffraction angle 2θout. In other words, the absorber film of Comparative Example 4 did not have a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. The RuTa film of Comparative Example 4 had almost the same composition as the RuTa film of Example 6, but contrary to Example 6, the diffraction angle 2θin of the RuTa film of Comparative Example 4 was greater than the diffraction angle 2θout. From this, it became clear that the relationship between the two diffraction angles (2θin and 2θout) is independent of the film composition.

[0175] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, a reflective mask blank for Comparative Example 4 was prepared.

[0176] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the RuTa film on the upper layer of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the CrN film on the lower layer was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0177] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 4 nm, which exceeded the acceptable range. In other words, it was found that the reflective mask obtained in this comparative example underwent a large fluctuation in the film stress of the absorber film when subjected to repeated heating and cooling treatments. Therefore, it was not possible to keep the changes in pattern shape and pattern dimensions within the acceptable range.

[0178] (Comparative Example 5) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0179] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and a RuW film (film thickness: 40 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the RuW film are shown below. RuW membrane Composition ratio Ru:W=30at%:70at% Targets: Ru target and W target Sputtering gas (flow ratio): Argon (100%) Deposition pressure: 0.23 Pa

[0180] The RuW film on the upper layer of the absorber film was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1. In Comparative Example 5, the thickness of the RuW film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is considered that the results of the above X-ray diffraction analysis reflect the characteristics of the RuW film.

[0181] In-plane X-ray diffraction analysis showed that the diffraction angle 2θin of the highest intensity peak was 38.9 degrees. Out-of-plane X-ray diffraction analysis showed that the diffraction angle 2θout of the highest intensity peak was 38.5 degrees. Therefore, in this comparative example, the diffraction angle 2θin of the absorber film was greater than the diffraction angle 2θout. In other words, the absorber film of Comparative Example 5 did not have a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. The RuW film of Comparative Example 5 had almost the same composition as the RuW film of Example 7, but contrary to Example 7, the diffraction angle 2θin of the RuW film of Comparative Example 5 was greater than the diffraction angle 2θout. From this, it became clear that the relationship between the two diffraction angles (2θin and 2θout) does not depend on the composition of the film.

[0182] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, a reflective mask blank for Comparative Example 5 was prepared.

[0183] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the RuW film on the upper layer of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the CrN film on the lower layer was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0184] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 4 nm, which exceeded the acceptable range. In other words, it was found that the reflective mask obtained in this comparative example underwent a large fluctuation in the film stress of the absorber film when subjected to repeated heating and cooling treatments. Therefore, it was not possible to keep the changes in pattern shape and pattern dimensions within the acceptable range.

[0185] (Comparative Example 6) A Ta conductive film made of tantalum was formed on the back surface of a glass substrate prepared in the same manner as in Example 1, in the same manner as in Example 1. Next, a multilayer reflective film and a protective film were deposited on the main surface of the glass substrate opposite to the conductive film, in the same manner as in Example 1, to obtain a substrate with a multilayer reflective film.

[0186] Next, using a DC magnetron sputtering apparatus, an absorber film was formed on the protective film of the multilayer reflective film substrate obtained above, by laminating a CrN film (film thickness: 4 nm) as the lower layer and an IrTa film (film thickness: 40 nm) as the upper layer in that order. The composition ratio and deposition conditions of the CrN film were the same as those of Example 1. The deposition conditions and composition ratio of the IrTa film are shown below. IrTa film Composition ratio Ir:Ta=70at%:30at% Targets: Ir target and Ta target Sputtering gas (flow ratio): Xenon (100%) Deposition pressure: 0.08 Pa

[0187] The IrTa film on the upper layer of the absorber film formed above was subjected to X-ray diffraction measurements using the in-plane method and the out-of-plane method, in the same manner as in Example 1. In Comparative Example 6, the thickness of the IrTa film (upper layer) was large relative to the total thickness of the absorber film, while the thickness of the CrN film (lower layer) was very small compared to the upper layer. Therefore, it is considered that the results of the above X-ray diffraction analysis reflect the characteristics of the IrTa film.

[0188] In-plane X-ray diffraction analysis showed that the diffraction angle 2θin of the highest intensity peak was 40.4 degrees. Out-of-plane X-ray diffraction analysis showed that the diffraction angle 2θout of the highest intensity peak was 40.1 degrees. Therefore, in this comparative example, the diffraction angle 2θin of the absorber film was greater than the diffraction angle 2θout. In other words, the absorber film of Comparative Example 6 did not have a structure in which the diffraction angle 2θin was less than or equal to the diffraction angle 2θout. The IrTa film of Comparative Example 6 had almost the same composition as the IrTa film of Example 3, but contrary to Example 3, the diffraction angle 2θin of the IrTa film of Comparative Example 6 was greater than the diffraction angle 2θout. From this, it became clear that the relationship between the two diffraction angles (2θin and 2θout) is independent of the film composition.

[0189] Next, in exactly the same manner as described above, a conductive film was deposited on the back surface of the glass substrate, and a multilayer reflective film, a protective film, and an absorber film were sequentially deposited on the substrate surface opposite to the conductive film. Subsequently, an etching mask film was deposited on the absorber film in the same manner as in Example 1. As described above, a reflective mask blank for Comparative Example 6 was prepared.

[0190] Next, using this reflective mask blank, a reflective mask was fabricated according to the same manufacturing method as in Example 1 described above. However, in the etching process of the absorber film, the upper IrTa film of the absorber film was patterned by dry etching using a fluorine-based gas (CF4 gas). Furthermore, the lower CrN film was patterned by dry etching using a mixed gas of chlorine and oxygen. This formed a pattern with a width (dimension) of 50 nm on the absorber film. The etching of the lower CrN film also removed the unnecessary etching mask film (CrN film). A reflective mask was then fabricated.

[0191] The obtained reflective mask was subjected to a continuous 10-cycle heating and cooling treatment, similar to Example 1. The change in pattern width (dimensions) before and after this continuous heating and cooling treatment was 4 nm, which exceeded the acceptable range. In other words, it was found that the reflective mask obtained in this comparative example underwent a large fluctuation in the film stress of the absorber film when subjected to repeated heating and cooling treatments. Therefore, it was not possible to keep the changes in pattern shape and pattern dimensions within the acceptable range.

[0192] As can be seen from the comparison of the examples and comparative examples described above, the absorber film of the reflective mask blank and the reflective mask includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis using the in-plane X-ray diffraction method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis using the out-of-plane X-ray diffraction method. As a result, even after repeated heating and cooling treatments, the change in pattern dimensions can be kept within an acceptable range, and consequently, the mask life is also superior. [Explanation of Symbols]

[0193] 1 circuit board 2. Conductive film on the back surface 3 Multilayer reflective film 4 Protective film 5 Absorbing membrane 6 Etching mask film 10A, 10B, 10C Reflective Mask Blanks 20 Reflective Masks

Claims

1. circuit board and A multilayer reflective film formed on the substrate, The system comprises an absorbent film formed on the multilayer reflective film, The absorber film includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis using the in-plane X-ray diffraction method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis using the out-of-plane X-ray diffraction method. A reflective mask blank characterized by the following features.

2. The reflective mask blank according to claim 1, characterized in that the absorbent membrane has a lower layer provided below the first layer.

3. The reflective mask blank according to claim 1 or 2, characterized in that the absorber film contains at least one of ruthenium, platinum, and iridium.

4. The reflective mask blank according to claim 1 or 2, characterized in that the first layer has a crystallite size of 3 nm or more.

5. The reflective mask blank according to claim 1 or 2, characterized in that the first layer has a crystallite size that is 2 nm or larger than the crystallite size of other layers provided below or above the first layer.

6. The reflective mask blank according to claim 1 or 2, characterized in that the first layer is etchable with a fluorine-containing gas.

7. The reflective mask blank according to claim 1 or 2, characterized in that the ratio of the thickness of the first layer to the thickness of the absorbent film is 0.5 or more.

8. circuit board and A multilayer reflective film formed on the substrate, The system comprises an absorbent film formed on the multilayer reflective film and on which a transfer pattern is formed, The absorber film includes a first layer having a structure such that the diffraction angle 2θin of the highest intensity peak obtained by analysis using the in-plane X-ray diffraction method is less than or equal to the diffraction angle 2θout of the highest intensity peak obtained by analysis using the out-of-plane X-ray diffraction method. A reflective mask characterized by the following features.

9. The reflective mask according to claim 8, characterized in that the absorbent membrane has a lower layer provided below the first layer.

10. The reflective mask according to claim 8 or 9, characterized in that the absorbent membrane contains at least one of ruthenium, platinum, and iridium.

11. The reflective mask according to claim 8 or 9, characterized in that the first layer has a crystallite size of 3 nm or more.

12. The reflective mask according to claim 8 or 9, characterized in that the first layer has a crystallite size that is 2 nm or larger than the crystallite size of other layers provided below or above the first layer.

13. The reflective mask according to claim 8 or 9, characterized in that the first layer is etchable with a fluorine-containing gas.

14. The reflective mask according to claim 8 or 9, characterized in that the ratio of the thickness of the first layer to the thickness of the absorbent film is 0.5 or more.

15. A method for manufacturing a semiconductor device, comprising using a reflective mask according to claim 8 or 9 and transferring the transfer pattern of the reflective mask to a transfer target on a semiconductor substrate.

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