JP6636581B2 - Reflective mask blank, method for manufacturing reflective mask, and method for manufacturing semiconductor device - Google Patents

Description

  The present invention relates to a reflective mask blank, a reflective mask, a method of manufacturing the same, and a method of manufacturing a semiconductor device, which are original plates for manufacturing an exposure mask used for manufacturing a semiconductor device.

  The type of light source of the exposure apparatus in semiconductor manufacturing has evolved while gradually shortening the wavelength, such as a 436 nm wavelength g-line, a 365 nm wavelength i-line, a 248 nm wavelength KrF laser, and a 193 nm wavelength ArF laser. In order to realize a proper pattern transfer, EUV lithography using extreme ultraviolet (EUV) having a wavelength of about 13.5 nm has been proposed. In EUV lithography, a reflective mask is used because the difference in absorptivity between materials for EUV light is small. As a reflective mask, for example, a multilayer reflective film that reflects exposure light is formed on a substrate, and a phase shift film that absorbs the exposure light is formed in a pattern on a protective film for protecting the multilayer reflective film. The formed one has been proposed. Light incident on a reflective mask mounted on an exposure machine (pattern transfer device) is absorbed by a portion having a phase shift film pattern, and is reflected by a multilayer reflective film at a portion having no phase shift film pattern. The image is transferred onto the semiconductor substrate through the reflection optical system. Part of the exposure light incident on the phase shift film pattern is reflected with a phase difference of about 180 degrees from the light reflected by the multilayer reflective film (phase shift), thereby obtaining a contrast.

  Technologies related to such a reflective mask for EUV lithography and mask blanks for manufacturing the same are disclosed in Patent Documents 1 to 3 and the like.

JP 2004-207593 A JP 2009-212220 A JP 2010-080659 JP

  The line width and pattern interval of a pattern forming a circuit on a semiconductor are continually miniaturized to increase the degree of integration, and therefore, a reflection type mask used for transferring a pattern on a semiconductor substrate. In addition, miniaturization of the phase shift film pattern is required. At the same time as pattern miniaturization, there is a demand for thinning of the phase shift film pattern. In an exposure apparatus using a reflective mask, light is incident on the mask at a slight angle from the vertical direction so that the optical axes of the incident light and the reflected light do not overlap. Then, if the phase shift film pattern of the mask has a thickness, a shadow based on the thickness is generated. The fact that the size of the transfer pattern changes by the amount of the shadow is called a shadowing effect. In order to reduce such shadowing effect, a thinner film is required.

  In the above-mentioned patent documents and the like, there is disclosed one in which a phase shift film is formed by a laminated structure of a plurality of materials. By forming the phase shift film with a laminated structure of a plurality of materials in this manner, the phase shift film pattern can be made finer and thinner than when a phase shift film is formed by one layer (one material). It is possible to However, when a laminated structure of a plurality of materials is used, the etching process and the like are inevitably complicated.

  SUMMARY OF THE INVENTION In view of the above, the present invention provides a reflection method capable of simplifying a process for generating a phase shift film pattern from a phase shift film (suppressing an increase in the number of processes) while reducing the thickness of the phase shift film pattern. It is an object of the present invention to provide a method for manufacturing a mold mask, a reflective mask blank and a reflective mask, and a method for manufacturing a semiconductor device.

  In order to solve the above problems, the present invention has the following configurations.

(Configuration 1)
A reflective mask blank in which a multilayer reflective film, a protective film, a phase shift film for shifting the phase of EUV light, and an etching mask film are formed in this order on a substrate, wherein the protective film is mainly made of ruthenium. The phase shift film has a laminated structure including a tantalum-based material layer containing tantalum and a ruthenium-based material layer containing ruthenium, and is laminated in the order of a tantalum-based material layer and a ruthenium-based material layer. The reflective mask blank is characterized in that the etching mask film is made of a tantalum-based material including tantalum.

(Configuration 2)
2. The reflective mask blank according to Configuration 1, wherein the etching mask film is made of a material containing tantalum and nitrogen.

(Configuration 3)
3. The reflective mask blank according to configuration 2, wherein the content of nitrogen contained in the etching mask film is 10 atomic% or more.

(Configuration 4)
The reflective mask blank according to any one of Configurations 1 to 3, wherein the etching mask film has an amorphous structure.

(Configuration 5)
On the surface of the protective film or on the side in contact with the phase shift film as a part of the protective film, a diffusion preventing layer containing ruthenium and oxygen for suppressing interdiffusion with the phase shift film is provided. 5. The reflective mask blank according to any one of 1 to 4 above.

(Configuration 6)
The reflective mask blank according to Configuration 5, wherein the thickness of the diffusion prevention layer is 0.2 nm or more and 1.5 nm or less.

(Configuration 7)
The uppermost layer of the multilayer reflective film is silicon (Si), and has a silicon oxide layer containing silicon and oxygen between the uppermost layer and the protective film. 6. The reflective mask blank according to any one of 6.

(Configuration 8)
The structure according to any one of Configurations 1 to 7, wherein the phase shift film is formed by a sputtering method, and has a stacked structure in which the phase shift film is continuously formed without being exposed to the air from the start of film formation to the end of film formation. Reflective mask blank.

(Configuration 9)
A method for manufacturing a reflective mask manufactured by using the reflective mask blank according to any one of the constitutions 1 to 8, wherein a resist film pattern is formed on the etching mask film, and the resist film pattern is used as a mask. Forming an etching mask film pattern by etching with an etching gas for removing a tantalum-based material; and etching with an etching gas for removing a ruthenium-based material using the etching mask film pattern as a mask. A ruthenium-based material layer pattern is formed, and then, using the ruthenium-based material layer pattern as a mask, an etching process is performed with an etching gas for removing the tantalum-based material, thereby forming a phase shift film pattern for forming a tantalum-based material layer pattern. And manufacturing a reflective mask. Law.

(Configuration 10)
The phase shift film pattern forming step includes a step of forming a ruthenium-based material layer pattern by etching with an etching gas containing oxygen gas, and simultaneously removing the resist film pattern. A method for manufacturing a reflective mask.

(Configuration 11)
The reflective type according to Configuration 10, wherein the phase shift film pattern forming step includes a step of forming the tantalum-based material layer pattern using the ruthenium-based material pattern as a mask and simultaneously removing the etching mask film pattern. Manufacturing method of mask.

(Configuration 12)
A reflective mask manufactured by the method for manufacturing a reflective mask according to any one of Configurations 9 to 11.

(Configuration 13)
A semiconductor having a step of setting the reflective mask according to the configuration 12 in an exposure apparatus having an exposure light source that emits EUV light, and transferring a transfer pattern to a resist film formed on a substrate to be transferred. Device manufacturing method.

  According to the reflective mask blank of the present invention (the reflective mask produced thereby), the phase shift film is formed in a laminated structure having a tantalum-based material layer containing tantalum and a ruthenium-based material layer containing ruthenium. This makes it possible to reduce the thickness of the phase shift film. In addition, a phase shift film is laminated on a ruthenium-based protective film in the order of a tantalum-based material layer and a ruthenium-based material layer, and an etching mask film made of a tantalum-based material is formed thereon, so that a phase shift film is formed. A process for generating a phase shift film pattern from a shift film can be simplified (suppression of an increase in processes). Therefore, it is possible to provide a manufacturing method in which the steps are simplified as the manufacturing method of the reflective mask. Further, even when considered as a method of manufacturing a semiconductor device, the effect of reducing the number of manufacturing steps of the reflective mask required for this is obtained, and the shadowing effect is reduced by thinning the phase shift film. be able to.

FIG. 3 is a view for explaining a schematic configuration of a reflective mask blank for EUV lithography according to the present invention. FIG. 3 is a schematic view illustrating a process of manufacturing a reflective mask for EUV lithography from a reflective mask blank for EUV lithography in Example 1. FIG. 4 is a schematic view showing a step of manufacturing a reflective mask for EUV lithography from a reflective mask blank for EUV lithography in Example 2. Schematic for explaining a method of manufacturing a semiconductor device using a reflective mask for EUV lithography according to the present invention Schematic view showing a process of manufacturing a reflective mask for EUV lithography from a reflective mask blank for EUV lithography as a comparative example

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. The following embodiments are one form of embodying the present invention, and do not limit the present invention within the scope thereof.

<Configuration of Reflective Mask Blank and Manufacturing Method Thereof>
FIG. 1 is a schematic diagram for explaining the configuration of a reflective mask blank for EUV lithography according to the present invention. As shown in FIG. 1, the reflective mask blank 10 includes a substrate 12, a multilayer reflective film 13 that reflects EUV light as exposure light, and ruthenium for protecting the multilayer reflective film 13 as main components. A Ru-based protective film 14 formed of a material, a phase shift film 16 for absorbing EUV light and reflecting some EUV light and shifting the phase thereof, and a top surface layer of the phase shift film 16. An etching mask film 17 having an etching selectivity with respect to the material, and these are stacked in this order. The phase shift film 16 is formed by laminating a tantalum-based material layer 161 and a ruthenium-based material layer 162 in this order. On the back surface of the substrate 12, a back conductive film 11 for electrostatic chuck is formed.

  Hereinafter, each layer will be described.

<< Substrate >>
The substrate 12 preferably has a low coefficient of thermal expansion in the range of 0 ± 5 ppb / ° C. in order to prevent distortion of the absorber film pattern due to heat during exposure to EUV light. As the material having a low coefficient of thermal expansion in this range, for example, SiO ₂ —TiO ₂ glass, multi-component glass ceramic, or the like can be used.

  The main surface on the side of the substrate 12 on which the transfer pattern (a phase shift film to be described later forms this) is processed to have a high flatness from the viewpoint of obtaining at least pattern transfer accuracy and position accuracy. . In the case of EUV exposure, the flatness is preferably 0.1 μm or less, more preferably 0.05 μm or less, and particularly preferably in a 132 mm × 132 mm region of the main surface of the substrate 12 on which the transfer pattern is formed. It is 0.03 μm or less. The main surface on the side opposite to the side on which the phase shift film is formed is a surface to be electrostatically chucked when set in an exposure apparatus, and has a flatness of 1 μm or less in a 142 mm × 142 mm area. It is preferably 0.5 μm or less, more preferably 0.3 μm or less. In the present specification, the flatness is a value representing the warpage (deformation amount) of the surface indicated by TIR (Total Indicated Reading), and a plane determined by the least square method with respect to the substrate surface is defined as a focal plane. The absolute value of the height difference between the highest position on the substrate surface above the plane and the lowest position on the substrate surface below the focal plane.

  In the case of EUV exposure, the surface smoothness required for the substrate 12 is such that the surface roughness of the main surface of the substrate 12 on the side on which the transfer pattern is formed is 0.1 nm or less in root mean square roughness (RMS). It is preferred that The surface smoothness can be measured with an atomic force microscope.

  Further, the substrate 12 preferably has high rigidity in order to prevent a film (such as the multilayer reflective film 13) formed thereon from being deformed by a film stress. In particular, those having a high Young's modulus of 65 GPa or more are preferable.

<< Multilayer reflective film >>
The multilayer reflective film 13 has a function of reflecting EUV light in a reflective mask for EUV lithography, and has a multilayer structure in which elements having different refractive indexes are periodically laminated.

  Generally, a thin film (high refractive index layer) of a light element or a compound thereof as a high refractive index material and a thin film (low refractive index layer) of a heavy element or a compound thereof as a low refractive index material are alternately formed. A multilayer film laminated for about ６０60 cycles is used as the multilayer reflective film 13. The multilayer film may be formed by stacking a high refractive index layer and a low refractive index layer in this order from a substrate 12 side, and a multilayer structure of a high refractive index layer / a low refractive index layer as one cycle, or may be stacked on the substrate 12 side. A plurality of low-refractive-index layers and high-refractive-index layers may be stacked in this order to form a low-refractive-index layer / high-refractive-index layer laminated structure in one cycle. It is preferable that the outermost layer of the multilayer reflective film 13, that is, the surface layer of the multilayer reflective film 13 opposite to the substrate 12 be a high refractive index layer. In the above-mentioned multilayer film, when the high refractive index layer and the low refractive index layer are laminated in this order from the substrate 12 and a multilayer structure of a high refractive index layer / a low refractive index layer is laminated in a plurality of periods, the uppermost layer has a low refractive index. In this case, if the low-refractive-index layer forms the outermost surface of the multilayer reflective film 13, it is easily oxidized and the reflectivity of the reflective mask decreases, so that the low-refractive-index layer is formed on the uppermost low-refractive-index layer. Further, it is preferable to form a high-refractive-index layer to form the multilayer reflective film 13. On the other hand, in the above-described multilayer film, when a low-refractive-index layer and a high-refractive-index layer are laminated in this order from the substrate 12 side, and a multilayer structure of a low-refractive-index layer / high-refractive-index layer is defined as one cycle, a plurality of cycles are required. Since the upper layer is a high refractive index layer, it may be left as it is.

  In the present embodiment, a layer containing Si is adopted as the high refractive index layer. The material containing Si may be a Si compound containing B, C, N, and O in addition to Si alone. By using a layer containing Si as the high refractive index layer, a reflective mask for EUV lithography excellent in reflectivity of EUV light can be obtained. Further, in the present embodiment, since a glass substrate is preferably used as the substrate 12, Si is also excellent in adhesion to the glass substrate. Further, as the low refractive index layer, a simple metal selected from Mo, Ru, Rh, and Pt, or an alloy thereof is used. For example, as the multilayer reflective film 13 for EUV light having a wavelength of 13 to 14 nm, a Mo / Si periodic laminated film in which Mo films and Si films are alternately laminated for about 40 to 60 cycles is preferably used. The high refractive index layer, which is the uppermost layer of the multilayer reflective film 13, is formed of silicon (Si), and a silicon oxide containing silicon and oxygen is provided between the uppermost layer (Si) and the Ru-based protective film 14. A layer may be formed. Thereby, mask cleaning resistance (film peeling resistance of the phase shift film pattern) can be improved.

  The reflectance of such a multilayer reflective film 13 alone is usually 65% or more, and the upper limit is usually 73%. The thickness and cycle of each constituent layer of the multilayer reflective film 13 may be appropriately selected depending on the exposure wavelength, and are selected so as to satisfy Bragg's law. Although a plurality of high refractive index layers and a plurality of low refractive index layers are present in the multilayer reflective film 13, the thicknesses of the high refractive index layers and the low refractive index layers do not have to be the same. Further, the thickness of the Si layer on the outermost surface of the multilayer reflective film 13 can be adjusted within a range that does not reduce the reflectance. The thickness of the outermost surface Si (high refractive index layer) can be 3 to 10 nm.

  The method for forming the multilayer reflective film 13 is known in the art, and can be formed by forming each layer by, for example, an ion beam sputtering method. In the case of the above-described Mo / Si periodic multilayer film, for example, first, an Si film having a thickness of about 4 nm is formed on the substrate 12 by using an Si target by an ion beam sputtering method, and then, about 3 nm is formed using a Mo target. Is formed, and this is defined as one cycle, and stacked for 40 to 60 cycles to form a multilayer reflective film 13 (the outermost layer is an Si layer).

<<< Ru-based protective film >>
The Ru-based protective film 14 is formed on the multilayer reflective film 13 in order to protect the multilayer reflective film 13 from dry etching and cleaning in a process of manufacturing a reflective mask for EUV lithography described later. The Ru-based protective film 14 is made of a material containing ruthenium as a main component (main component: 50 at% or more), and may be a single Ru metal, or Ru may include Nb, Zr, Y, B, Ti, La, Mo, and Co. , Re, etc., may be used, and may contain nitrogen. Further, the Ru-based protective film 14 has a laminated structure of three or more layers, the lowermost layer and the uppermost layer are layers made of the above-mentioned Ru-containing material, and between the lowermost layer and the uppermost layer, a metal other than Ru, or An alloy may be used.

  The thickness of the Ru-based protective film 14 made of such Ru or an alloy thereof is not particularly limited as long as it can function as the protective film, but from the viewpoint of EUV light reflectance, preferably, It is 1.5 to 8.0 nm, more preferably 1.8 to 6.0 nm.

  As a method for forming the Ru-based protective film 14, a method similar to a known film forming method can be employed without particular limitation. Specific examples include a sputtering method and an ion beam sputtering method.

<< Phase shift film >>

  A phase shift film 16 is formed on the Ru-based protection film 14 (when a diffusion prevention layer is formed on the Ru-based protection film 14, the phase shift film 16 is formed on the diffusion prevention layer. Is done). The phase shift film 16 absorbs EUV light and reflects part of the EUV light to shift the phase. That is, in the reflection type mask in which the phase shift film 16 is patterned, in the remaining portion, the phase shift film 16 is partially reflected so as not to affect the pattern transfer while absorbing the EUV light. 13 to form a phase difference with the reflected light from the light source 13. The phase shift film 16 is formed such that the reflectance for EUV light is 1 to 30%, and the phase difference between the reflected light from the phase shift film 16 and the reflected light from the multilayer reflective film 13 is 170 to 190 degrees. . The thickness of the phase shift film 16 is appropriately determined according to the material to be used and the design value of the reflectance, and so that the phase difference falls within the above range.

  The phase shift film 16 is formed by laminating a tantalum-based material layer 161 and a ruthenium-based material layer 162 in this order. The tantalum-based material layer 161 is made of tantalum alone or a tantalum-based material containing tantalum, and is a TaB alloy containing Ta and B, a TaSi alloy containing Ta and Si, and Ta and other transition metals (for example, Pt, Pd, It may be a Ta alloy containing Ag), a tantalum-based compound obtained by adding N, O, H, C, or the like to Ta metal or an alloy thereof. The ruthenium-based material layer 162 may be a single Ru metal, or may be a Ru alloy in which Ru contains a metal such as Nb, Zr, Y, B, Ti, La, Mo, Co, or Re. Further, a ruthenium-based compound obtained by adding N, O, H, C, or the like to Ru metal or an alloy thereof may be used. The thickness of the phase shift film 16, that is, the thickness of each of the tantalum-based material layer 161 and the ruthenium-based material layer 162 is adjusted so that the phase difference is 170 to 190 degrees according to the design value of the reflectance. , And an appropriate combination of film thicknesses. The phase shift film 16 is preferably formed continuously from the start of film formation to the end of film formation without exposure to the atmosphere. By doing so, formation of an oxide layer (tantalum oxide layer) on the surface of the tantalum-based material layer 161 can be prevented (a step for removing the tantalum oxide layer is not required).

  The phase shift film 16 composed of such a layer of tantalum or a tantalum compound and a layer of ruthenium or a ruthenium compound can be formed by a known method such as a DC sputtering method or an RF sputtering method.

  The tantalum-based material or ruthenium-based material is usually an alloy of tantalum or an alloy of ruthenium. The crystal state of the phase shift film 16 made of such an alloy is preferably an amorphous (amorphous) or microcrystalline structure from the viewpoint of smoothness. If the phase shift film 16 is not smooth, the edge roughness of the phase shift film pattern becomes large, and the dimensional accuracy of the pattern may deteriorate. The surface roughness of the phase shift film 16 is preferably 0.5 nm RMS or less, more preferably 0.4 nm RMS or less, and even more preferably 0.3 nm RMS or less.

  Ta is a phase shift film material excellent in processability because it has a large EUV light absorption coefficient and can be easily dry-etched with a chlorine-based gas or a fluorine-based gas. Further, by adding B, Si, Ge, or the like to Ta, an amorphous material can be easily obtained, and the smoothness of the phase shift film 16 can be improved. Further, if N or O is added to Ta, the resistance of the phase shift film 16 to oxidation is improved, so that the effect of improving the stability over time can be obtained.

  Ru is a film material having a high reflectivity of EUV light and easy to obtain a contrast by a phase shift effect. Further, the refractive index to EUV light is small, and in combination with the above-described tantalum-based material layer, a phase shift effect can be obtained with a small film thickness. Further, by performing etching with oxygen gas, an excellent selectivity with respect to the tantalum-based material layer can be obtained, so that an effect of obtaining a highly accurate and fine pattern can be obtained.

<< etching mask film >>
On the phase shift film 16, an etching mask film 17 is further formed. The etching mask film 17 has an etching selectivity with respect to the ruthenium-based material layer 162 which is the outermost surface layer of the phase shift film 16, and also has an etching gas for the tantalum-based material layer 161 which is a lower layer of the phase shift film 16. It is formed of a material that can be etched (has no etching selectivity). Specifically, it is formed of a tantalum-based material including tantalum, and is Ta alone, a TaB alloy containing Ta and B, a Ta alloy containing Ta and other transition metals (for example, Hf, Zr, Pt, W), and the like. , Ta metal or an alloy thereof, a tantalum-based compound obtained by adding N, O, H, C, or the like. In particular, the tantalum-based material used as the etching mask film is present on the outermost surface of the reflective mask blank, so that the surface is easily oxidized by natural oxidation or cleaning. When the tantalum-based material is oxidized, the etching mask film is not removed at the same time when the tantalum-based material constituting the phase shift film is etched with a chlorine-based gas, which affects the simplification of the process of the reflective mask. . Therefore, the tantalum-based material used as the etching mask film is preferably made of a material and composition having high oxidation resistance, which is not easily oxidized on the surface. Further, in consideration of the simplification of the process of the reflection type mask, it is preferable to use a material and a composition having a higher etching rate than a tantalum-based material layer constituting a phase shift film in a chlorine-based gas. As a preferable material, a material containing tantalum and nitrogen is preferable, and the content of nitrogen is desirably 10 atomic% or more. From the viewpoint of suppressing pseudo defects in the defect inspection of the reflective mask blank, the surface of the etching mask film is preferably smooth, and in this case, the nitrogen content is desirably 75 atomic% or less. It is desirable that the content of nitrogen in the etching mask film be 10 to 75 at%, more preferably 10 to 60 at%, and 15 to 50 at%.
Further, in consideration of the etching rate of the etching mask film, it is preferably amorphous.

  The etching mask film 17 can be formed by a known method such as a sputtering method such as a DC sputtering method or an RF sputtering method.

  The thickness of the etching mask film 17 is preferably 5 nm or more from the viewpoint of ensuring the function as a hard mask. As will be described later, since the etching mask film 17 is removed at the same time as the etching process of the tantalum-based material layer 161 in the manufacturing process of the reflection type mask, the etching mask film 17 is formed to have a thickness substantially equal to that of the tantalum-based material layer 161. May be used. Considering the thickness of the tantalum-based material layer 161 constituting the phase shift film, the thickness of the etching mask film 17 is preferably 5 nm or more and 20 nm or less, and more preferably 5 nm or more and 15 nm or less.

<< Back conductive film >>
On the back surface side of the substrate 12 (the side opposite to the surface on which the multilayer reflective film 13 is formed), a back surface conductive film 11 for electrostatic chuck is formed. The electrical characteristics required for the back surface conductive film 11 for the electrostatic chuck are usually 100 Ω / sq or less. The back conductive film 11 can be formed by, for example, a magnetron sputtering method or an ion beam sputtering method using a metal or alloy target such as chromium or tantalum. The thickness of the back surface conductive film 11 is not particularly limited as long as it satisfies the function for an electrostatic chuck, but is usually 10 to 200 nm.

  As above, the configuration of the reflective mask blank 10 of the present embodiment has been described for each layer. Incidentally, the reflection type mask blank may be one provided with a resist film on the phase shift film 16. Further, a diffusion prevention layer may be provided between the Ru-based protective film 14 and the phase shift film 16 (on the surface of the Ru-based protective film 14 or on the side in contact with the phase shift film 16 as a part of the Ru-based protective film 14). It may be.

  Here, the diffusion preventing layer will be described. EUV exposure equipment is a technology that has not yet reached full-scale commercialization, and the power of the exposure light source is selected to be suitable for R & D (currently, a light source of about 15 W is used). Naturally, in the case of full-scale commercialization, it is necessary to obtain at least a certain throughput, and for that purpose, it is necessary to increase the power of the exposure light source. When the exposure light source has a high power, the amount of heat generated per unit time in the reflective mask during exposure (pattern transfer) also increases (because the energy of light absorbed by the phase shift film is converted into heat). Due to the thermal diffusion caused by heat, mutual diffusion occurs between the protective film and the material of the phase shift film pattern adjacent thereto. Due to such interdiffusion, the reflectance of EUV light fluctuates, and the function as a reflective mask may be reduced by repeated use (contrast as designed may not be obtained). As a means for solving this problem, the diffusion prevention layer is provided on the surface of the Ru-based protective film 14 or on the side in contact with the phase shift film as a part of the protective film. By forming the diffusion prevention layer, the thermal diffusion of the protective film and the phase shift film is suppressed even in a use environment where the exposure light source is high power (80 W or more), so that a decrease in the EUV light reflectance is suppressed. . Therefore, it is possible to obtain a reflective mask blank in which a decrease in the phase effect is suppressed.

  The diffusion preventing layer is formed of a material containing ruthenium (Ru) and oxygen (O), and may contain Ru and O, and may contain N or H. Ru may be a single Ru metal or a Ru alloy (preferably the same material system as the protective film material). For example, when the protective film is made of Ru, the material of the diffusion preventing layer includes RuO, RuON and the like. When the protective film is made of a Ru alloy (for example, RuNb), RuNbO, RuNbON, or the like may be used as a material of the diffusion prevention layer. From the viewpoint of suppression of mutual diffusion due to thermal diffusion and reflectivity to EUV light, the ratio (atomic%) of ruthenium (Ru) to oxygen (O) in the diffusion prevention layer 15 is 0.8 when Ru is 1. It is desirable to set it to 2.2 or more, preferably 1.0 or more and 2.0 or less.

  As a method of forming and forming the diffusion prevention layer, a sputtering method (ion beam sputtering, DC sputtering, RF sputtering) or an annealing treatment of the surface of the Ru-based protective film 14 in the atmosphere, oxygen gas, or ozone gas atmosphere is performed. Thus, a diffusion preventing layer may be formed. In the case of laminating on the Ru-based protection film 14 by a sputtering method, the diffusion prevention layer 15 can be formed by freely selecting the above-mentioned materials and the like, but the surface of the Ru-based protection film 14 is subjected to an annealing treatment. In the case where the diffusion prevention layer 15 is formed by using, for example, an oxide film based on the material of the Ru-based protection film 14 is used. In the case of stacking by the sputtering method, the diffusion prevention layer 15 is newly stacked on the Ru-based protection film 14 (the film thickness is increased). In the case of performing the annealing treatment, a part of the Ru-based protective film 14 has the function of the diffusion preventing layer 15 without increasing the overall film thickness.

  The thickness of the diffusion prevention layer is preferably 0.2 nm or more and 1.5 nm or less from the viewpoint of the effect of suppressing thermal diffusion and the reflectance characteristics with respect to EUV light. If it is less than 0.2 nm, the effect of suppressing thermal diffusion is not sufficiently exhibited, and if it is more than 1.5 nm, the reflectance to EUV light is less than 63%, which is not preferable. More preferably, it is 0.3 nm or more and 1.2 nm or less, and further preferably, 0.5 nm or more and 1.0 nm or less.

<Reflective mask and manufacturing method thereof>
A reflective mask can be manufactured using the reflective mask blank 10 of the present embodiment described above. For the production of a reflective mask for EUV lithography, a photolithography method capable of performing high-definition patterning is most preferable.

  In the present embodiment, a method of manufacturing a reflective mask using a photolithography method will be described. In addition, since the embodiments will be described later with reference to the drawings, only a brief description will be given here.

Step 1. A resist film is formed on the outermost surface of the reflective mask blank 10 (unnecessary if a resist film is provided as the reflective mask blank 10), and a desired pattern is drawn (exposed) on the resist film. By rinsing, a predetermined resist film pattern is formed.
Step 2. Using this resist film pattern as a mask, dry etching is performed with a chlorine-based etching gas (an etching gas for removing a tantalum-based material) to form an etching mask film pattern.
Step 3. Next, using the etching mask film pattern as a mask, dry etching is performed with an etching gas containing oxygen gas (an etching gas for removing a ruthenium-based material) to form a ruthenium-based material layer pattern (A. Resist in this step). The film pattern is removed at the same time).
Step 4. Using this ruthenium-based material layer pattern as a mask, a tantalum-based material layer pattern is formed by performing dry etching with a chlorine-based etching gas (B. In this step, the etching mask film pattern is simultaneously removed).

The steps 1 to 4 constitute a phase shift film pattern forming step, that is, a phase shift film pattern is formed by forming the ruthenium-based material layer pattern and the tantalum-based material layer pattern. . Then, wet cleaning using an acidic or alkaline aqueous solution is performed, and a reflective mask for EUV lithography achieving high reflectance is obtained. Examples of the chlorine-based etching gas include chlorine-based gases such as Cl ₂ , SiCl ₄ , CHCl ₃ , CCl ₄ , and BCl ₃ , a mixed gas thereof, a mixed gas containing a chlorine-based gas and He at a predetermined ratio, and a chlorine-based etching gas. A mixed gas containing a system gas and Ar at a predetermined ratio is exemplified.
As an etching gas containing an oxygen gas for removing a ruthenium-based material, in addition to an oxygen gas, a fluorine gas, a chlorine gas, a bromine gas, an iodine gas, a halogen gas containing at least one of these, and a halogenated gas are used. A mixed gas containing at least one or more selected from the group consisting of hydrogen gas and oxygen gas may be used.

  According to the method for manufacturing a reflective mask based on the reflective mask blank 10 of the present embodiment, as shown in A and B of the steps 3 and 4, different layers are simultaneously removed by one etching. Therefore, the number of manufacturing steps of the reflective mask can be reduced. Therefore, according to the configuration of the reflective mask blank 10 of the present embodiment, it is possible to provide a mask blank capable of reducing the number of mask manufacturing steps.

<Semiconductor device manufacturing method>
Using the reflection type mask of the present embodiment, a transfer pattern based on the phase shift film pattern of the reflection type mask is formed on the semiconductor substrate by lithography technology, and various other steps are performed to form various transfer steps on the semiconductor substrate. Can be manufactured.

  As a more specific example, a pattern transfer device (exposure device) 50 shown in FIG. 4 transfers a pattern to a semiconductor substrate with a resist film (substrate to be transferred) 30 by EUV light using the reflective mask of the present embodiment. The method will be described.

  The pattern transfer device 50 equipped with the reflective mask 20 of the present embodiment includes a laser plasma X-ray source (exposure light source) 31, a reflective mask 20, a reduction optical system 32, and the like. As the reduction optical system 32, an X-ray reflection mirror is used. The laser plasma X-ray source (exposure light source) 31 has a power of 80 W from the viewpoint of optimizing the throughput.

  The pattern reflected by the reflective mask 20 by the reduction optical system 32 is reduced to about 1/4 in general. For example, a wavelength band of 13 to 14 nm is used as the exposure wavelength, and the optical path is set in advance so as to be in a vacuum. In such a state, the EUV light obtained from the laser plasma X-ray source 31 is made incident on the reflection type mask 20, and the reflected light is passed through the reduction optical system 32 to the semiconductor substrate with resist film (substrate to be transferred) 30. Transfer (transfer a transfer pattern to a resist film formed on a substrate to be transferred).

  The EUV light incident on the reflective mask 20 is absorbed by the phase shift film 16 in the portion where the phase shift film 16 remains and is not reflected, whereas, in the portion where the phase shift film 16 does not remain, the multilayer reflective film is used. The EUV light is incident on and is reflected at 13. In this manner, an image formed by the light reflected from the reflective mask 20 is incident on the reduction optical system 32, and the exposure light passing through the reduction optical system 32 is applied to a semiconductor substrate with a resist film (substrate to be transferred). A transfer pattern is formed on the resist layer on the substrate 30 (Note that a part of the EUV light is reflected by the phase shift film 16, and this light is shifted by 180 degrees in phase with respect to the light reflected from the multilayer reflective film 13) To increase the contrast of the image). Then, by developing this exposed resist layer, a resist pattern can be formed on the semiconductor substrate with a resist film (transferred substrate) 30. Then, by performing etching or the like using the resist pattern as a mask, a predetermined wiring pattern can be formed on the semiconductor substrate, for example. The semiconductor device is manufactured through these steps and other necessary steps.

  Hereinafter, each embodiment will be described with reference to the drawings. In each embodiment, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be simplified or omitted.

  FIG. 2 is a schematic diagram illustrating a process of manufacturing a reflective mask for EUV lithography from a reflective mask blank for EUV lithography in Example 1.

  As shown in FIG. 2A, the reflective mask blank 10 of Example 1 includes a back conductive film 11, a substrate 12, a multilayer reflective film 13, a Ru-based protective film 14, a diffusion prevention layer 15, And a phase shift film 16. The phase shift film 16 is formed of the tantalum-based material layer 161 and the ruthenium-based material layer 162 (laminated in this order from the bottom), and the etching mask film 17 is formed on the phase shift film 16.

((Reflective mask blank))
First, the mask blank 10 according to the first embodiment will be described.
(((Back side conductive film)))
A back conductive film 11 made of CrN was formed on the back surface of the SiO ₂ —TiO ₂ glass substrate 12 by magnetron sputtering under the following conditions.
Back conductive film formation conditions: Cr target, Ar + N ₂ gas atmosphere (Ar: N ₂ : 90%: N: 10%), film thickness 20 nm.

(((Multilayer reflective film)))
Next, a multilayer reflective film 13 was formed on the main surface of the substrate 12 opposite to the side on which the back conductive film 11 was formed. As the multilayer reflective film 13 formed on the substrate 12, a Mo / Si periodic multilayer reflective film was employed in order to make the multilayer reflective film suitable for EUV light of 13.5 nm. The multilayer reflective film 13 was formed by using an Mo target and a Si target, and alternately stacking Mo layers and Si layers on the substrate 12 by ion beam sputtering (Ar gas atmosphere). First, a Si film was formed with a thickness of 4.2 nm, and subsequently, a Mo film was formed with a thickness of 2.8 nm. This was defined as one cycle, and 40 cycles were similarly laminated. Finally, a Si film was formed to a thickness of 4.0 nm to form a multilayer reflective film 13.

(((Ru-based protective film)))
Subsequently, a Ru protective film 14 having a thickness of 2.5 nm was formed by ion beam sputtering (Ar gas atmosphere) using a Ru target.

(((Diffusion prevention layer)))
Next, high concentration ozone gas treatment was performed on the surface of the Ru-based protective film 14. In this case, the concentration of the ozone gas was 100% by volume, the processing time was 10 minutes, and the substrate with the multilayer reflective film was heated to 60 degrees. Thus, a diffusion preventing layer 15 of a Ru oxide film (1.0 nm in thickness) was formed on the side of the Ru-based protective film 14 in contact with the phase shift film 16. That is, a part of the Ru-based protection film 14 has the function of the diffusion prevention layer 15 (1.0 nm of the surface layer side of the 2.5 nm Ru-based protection film 14 functions as the diffusion prevention layer 15).

(((Phase shift film)))
Next, the phase shift film 16 was formed by laminating the TaN film (the tantalum-based material layer 161) and the Ru film (the ruthenium-based material layer 162) by DC sputtering. As the TaN film, a 5 nm-thick TaN film (Ta: 92.5 at%, N: 7.5 at%) was formed by a reactive sputtering method in a mixed gas atmosphere of Ar gas and N ₂ gas as a tantalum target. As the Ru film, a Ru film having a thickness of 27 nm was formed by sputtering in an Ar gas atmosphere using a ruthenium target (continuous film formation from the TaN film to the Ru film without being exposed to the air).
The refractive index, n, and extinction coefficient k of the TaN film and the Ru film formed above at a wavelength of 13.5 nm were respectively as follows.
TaN: n → 0.94, k → 0.034
Ru: n → 0.89, k → 0.017
The thicknesses of the TaN film and the (tantalum-based material layer 161) Ru film (ruthenium-based material layer 162) are set so that the reflectance is 26% and the phase difference is 180 degrees at a wavelength of 13.5 nm. It is.

(((Etching mask film)))
Next, a TaN film serving as an etching mask film 17 was formed on the phase shift film 16 to a thickness of 5 nm by DC sputtering. The composition ratio of the etching mask film 17 was set to 87.5 at% for Ta and 12.5 at% for N in order to improve the oxidation resistance. Further, the etching mask film 17 was made amorphous.

  Thus, the reflective mask blank 10 of Example 1 was obtained.

  In addition, in the state of the reflective mask blank (without the etching mask film) manufactured by the same manufacturing method as described above, the reflectance of the surface of the phase shift film with respect to EUV light was measured, and was 25.9%. Next, as an evaluation of the use environment assuming that the exposure light source has high power, a heat treatment was performed at 80 ° C. for 1 hour in a vacuum, and the surface of the phase shift film after the heat treatment was reflected by EUV light. When the ratio was measured, it was almost unchanged at 25.8%. This is presumed that the thermal diffusion between the Ru-based protective film 14 and the phase shift film 16 was suppressed by the diffusion prevention layer 15. That is, since the diffusion preventing layer 15 is formed, the thermal diffusion between the protective film and the phase shift film is suppressed even under the use environment where the exposure light source is at a high power, so that the decrease in the EUV light reflectance is suppressed. Therefore, it is possible to obtain a reflection type mask in which a decrease in the phase effect is suppressed.

  Further, as in the present embodiment, the tantalum-based material is formed by forming the phase shift film 16 by a sputtering method as a laminated film continuously formed without being exposed to the air from the start of film formation to the end of film formation. This is preferable in that an oxide layer (a tantalum oxide layer) can be prevented from being formed on the surface of the layer 161. That is, when a tantalum-based material layer is included as a material of the phase shift film, the tantalum oxide layer is formed on the surface of the phase shift film when exposed to the atmosphere. The tantalum oxide layer cannot be etched unless a fluorine-based gas is used as an etching gas, which complicates the etching process, which is not preferable. However, according to the present embodiment, this problem can be avoided.

((Reflective mask))
Next, a reflective mask 20 was manufactured using the reflective mask blank 10 described above.

Step 1. A resist film 18 having a thickness of 40 nm is formed on the etching mask film 17 of the reflective mask blank 10 (FIG. 2B), a desired pattern is drawn (exposed) on the resist film, and further developed and rinsed. Thus, a predetermined resist film pattern 18a is formed.
Step 2. Using this resist film pattern 18a as a mask, the etching mask film 17 is dry-etched with Cl ₂ gas to form an etching mask film pattern 17a (FIG. 2C).
Step 3. The Ru film (ruthenium-based material layer 162) is dry-etched with O ₂ gas using the etching mask film pattern 17a as a mask to form a ruthenium-based material layer pattern 162a (FIG. 2D). At this time, the resist film pattern 18a is also removed at the same time (step deletion A).
Step 4. Using the ruthenium-based material layer pattern 162a as a mask, the TaN film (the tantalum-based material layer 161) is dry-etched with Cl ₂ gas to form the tantalum-based material layer pattern 161a (FIG. 2E). At this time, the etching mask film pattern 17a is removed at the same time (step deletion B).
The phase shift film pattern 16a is formed by forming the ruthenium-based material layer pattern 162a and the tantalum-based material layer pattern 161a, and the reflection mask 20 is manufactured.

  According to the method of manufacturing the reflective mask 20 based on the reflective mask blank 10 of the present embodiment, the phase shift film 16 has a laminated structure of the tantalum-based material layer 161 (5 nm) and the ruthenium-based material layer 162 (27 nm). By forming the phase shift film pattern, the reflectivity of the phase shift film pattern can be made as high as 26%, so that a high phase effect can be obtained, and the film thickness of the phase shift film pattern can be made as thin as 32 nm. As a result, a reflective mask having a reduced shadowing effect was obtained. Further, as described above, since different layers are simultaneously deleted by one etching, the number of manufacturing steps of the reflective mask can be reduced (step deletion A and B), and the phase shift film can be reduced. This is very useful because it suppresses the complexity of the process due to the multi-layer structure of 16.

  Further, according to the reflective mask 20 of the present embodiment, as described above, the thermal diffusion between the protective film and the phase shift film is suppressed even under the use environment where the exposure light source is at a high power. Is suppressed. Therefore, even when the reflective mask 20 is repeatedly used in an environment of a high-power exposure light source, a decrease in the phase effect is suppressed, so that a stable semiconductor device can be manufactured, which is very useful.

  FIG. 3 is a schematic diagram illustrating a process of manufacturing a reflective mask for EUV lithography from a reflective mask blank for EUV lithography in Example 2.

  The second embodiment differs from the first embodiment in that the thicknesses of the TaN film (the tantalum-based material layer 161) and the Ru film (the ruthenium-based material layer 162) in the phase shift film are 24 nm and 16 nm, respectively. The composition ratio is the same as in Example 1.) Further, the thickness of the TaN film (tantalum-based material layer 161) and the thickness of the Ru film (ruthenium-based material layer 162) are set so that the reflectance is 6% at a wavelength of 13.5 nm. (The same point is set so that the phase difference is 180 degrees). As the etching mask film 17, a TaN film was formed to a thickness of 15 nm by DC sputtering (the composition ratio and the crystal structure were the same as in Example 1). The process for manufacturing the reflective mask 20 from the reflective mask blank 10 is the same as that in the first embodiment, and a description thereof will be omitted.

  In the same manner as in Example 1, the use environment was evaluated on the assumption that the exposure light source had high power. Using a reflective mask blank (without an etching mask film) manufactured by the same manufacturing method as in Example 2, the reflectance of the phase shift film surface with respect to EUV light was measured, and was 5.9%. Next, a heat treatment was performed at 80 ° C. for 1 hour in a vacuum, and the reflectivity of the phase shift film surface with respect to EUV light after the heat treatment was measured. Was.

  According to the second embodiment, the reflectivity of the phase shift film pattern is 6.0 by forming the phase shift film 16 in a laminated structure of the tantalum-based material layer 161 (24 nm) and the ruthenium-based material layer 162 (16 nm). % And the thickness of the phase shift film pattern can be made as thin as 40 nm, and a reflective mask with a reduced shadowing effect can be obtained. Further, the manufacturing process of the reflective mask 20 from the reflective mask blank 10 is the same as that of the first embodiment, and since different layers are simultaneously deleted by one etching, the reflective mask 20 is manufactured. The number of manufacturing processes can be reduced (process deletions A and B), and the complexity of the process due to the multi-layered phase shift film 16 is suppressed, which is very useful.

  Further, according to the reflective mask manufactured from the reflective mask blank of the second embodiment, the heat diffusion between the protective film and the phase shift film is reduced even under the use environment where the exposure light source is high power, as in the first embodiment. Since this is suppressed, a decrease in the reflectivity of EUV light is suppressed. Therefore, even when the reflection type mask is repeatedly used in an environment of a high power exposure light source, a decrease in the phase effect is suppressed, so that a stable semiconductor device can be manufactured, which is very useful.

  In Example 3, although not particularly shown, a silicon oxide layer containing silicon and oxygen was provided between the uppermost layer (Si) of the multilayer reflective film 13 and the Ru-based protective film 14 in Example 1. It is to be formed.

In the third embodiment, after forming the multilayer reflective film 13, a heat treatment at 200 ° C. is performed in the air, and a silicon oxide film having a thickness of 1.5 nm is formed on the surface layer of the outermost silicon (Si) film of the multilayer reflective film 13. An object (SiO ₂ ) layer was formed, and then a Ru protective film having a thickness of 2.5 nm was formed by DC sputtering (Ar gas atmosphere) using a Ru target. After that, a reflective mask blank and a reflective mask were formed in the same manner as in Example 1. The obtained reflective mask blank and reflective mask obtained the same effects as those of the above-mentioned Example 1, and also obtained good results regarding the mask cleaning resistance described below. RCA cleaning was repeated (100 times) on the reflective mask obtained by the manufacturing method of Example 3, and the cleaning resistance of the reflective mask was evaluated. As a result of observation by a scanning electron microscope (SEM), no peeling of the phase shift film pattern was observed, and the mask cleaning resistance was good.

  The point that a silicon oxide layer containing silicon and oxygen is formed between the uppermost layer (Si) of the multilayer reflective film 13 and the Ru-based protective film 14 will be described. In a conventional reflective mask, a protective film is provided on a multilayer reflective film, Si diffuses into the Ru-based protective film between the Si layer and the protective film, and further undergoes oxidation to form silicon oxide. The film is peeled off due to repeated washing in the manufacturing process of the mask and after use as a finished product. On the other hand, by forming a silicon oxide layer containing silicon and oxygen between the uppermost Si of the multilayer reflective film 13 and the Ru-based protective film 14, the uppermost layer of the multilayer reflective film 13 and the Ru-based Since diffusion with the protective film 14 is suppressed, a decrease in the reflectivity of EUV light is suppressed, and resistance to mask cleaning (resistance to peeling of the phase shift film pattern) is improved. The thickness of the silicon oxide layer is preferably 0.2 nm or more from the viewpoint of suppressing transfer of Si to the protective film. Further, the thickness is preferably 3 nm or less from the viewpoint of suppressing a decrease in the reflectance of EUV light. A more preferable range based on both viewpoints is 0.5 to 2 nm. The silicon oxide layer can be formed by an ion beam sputtering method, a sputtering method, a CVD method, a vacuum evaporation method, or the like. The silicon oxide (Si), which is the uppermost layer of the multilayer reflective film 13, is annealed to form a silicon oxide layer. A silicon oxide layer may be formed on the surface of the upper silicon layer.

(Comparative example)
FIG. 5 is a schematic view illustrating a process of manufacturing a reflective mask for EUV lithography from a reflective mask blank for EUV lithography as a comparative example. The comparative example was prepared for comparison with the example 1, and does not indicate that the comparative example is a conventional example (known).

In this comparative example, as shown in FIG. 5A, the back conductive film 11 to the phase shift film 16 (the tantalum-based material layer 161, the ruthenium-based material layer) are compared with the reflective mask blank 10 of the first embodiment. Up to 162), the structure is the same including the film thickness of each layer. The difference from the reflective mask blank 10 of the first embodiment is the etching mask film. In the reflective mask blank 100 of the comparative example, the etching mask film 170 is formed on the phase shift film 16 by the SiO ₂ film. The SiO ₂ film serving as an etching mask film was formed with a thickness of 5 nm by RF sputtering.

((Reflective mask))
Next, a description will be given of a manufacturing process of the reflective mask 20 when the reflective mask blank 100 is used.

Step 1. A resist film 18 having a thickness of 40 nm is formed on the etching mask film 170 of the reflective mask blank 100 (FIG. 5B), a desired pattern is drawn (exposed) on the resist film, and further developed and rinsed. Thus, a predetermined resist film pattern 18a is formed.
Step 2. Using this resist film pattern 18a as a mask, the SiO ₂ film (etching mask film 170) is dry-etched with a fluorine-based gas (CF ₄ gas) to form an etching mask film pattern 170a (FIG. 5C). .
Step 3. The Ru film (ruthenium-based material layer 162) is dry-etched with O ₂ gas using the etching mask film pattern 170a as a mask to form a ruthenium-based material layer pattern 162a (FIG. 5D). At this time, the resist film pattern 18a is also removed at the same time (step deletion A).
Step 4. Using the etching mask film pattern 170a and the ruthenium-based material layer pattern 162a as a mask, the TaN film (the tantalum-based material layer 161) is dry-etched with Cl ₂ gas to form the tantalum-based material layer pattern 161a (FIG. 5 ( e)).
Step 5. The etching mask film pattern 170a is removed by a fluorine-based gas (CF ₄ gas).
By forming the ruthenium-based material layer pattern 162a and the tantalum-based material layer pattern 161a, the phase shift film pattern 16a is formed, whereby the reflection mask 20 is manufactured. (The manufactured reflective mask 20 has the same configuration as the reflective mask 20 of the first embodiment.)

  In the method for manufacturing the reflective mask 20 based on the reflective mask blank 100 in the comparative example, a step of removing the etching mask film pattern 170a is required as step 5. On the other hand, according to the reflective mask blanks 10 of Examples 1 to 3 according to the present invention, the step 5 in the comparative example is unnecessary, and the reflective mask obtained can be obtained while reducing the number of manufacturing steps of the reflective mask. As the mask, a reflective mask 20 having the same configuration as that of the comparative example was obtained.

  10. . . 11. reflective mask blank, . . Substrate, 13. . . 13. multilayer reflective film; . . 14. Ru-based protective film, . . Diffusion prevention layer, 16. . . Phase shift film, 16a. . . 16. phase shift film pattern; . . Etching mask film, 17a. . . 17. etching mask film pattern; . . Resist film, 18a. . . Resist pattern, 20. . . Reflective mask, 30. . . 30. semiconductor substrate with resist film (substrate to be transferred); . . 50. laser plasma X-ray source (exposure light source) . . 161. Pattern transfer device (exposure device) . . Tantalum-based material layer, 161a. . . Tantalum-based material layer pattern, 162. . . Ruthenium-based material layer, 162a. . . Ruthenium based material layer pattern

Claims (10)

A reflective mask blank,
Board and
A multilayer reflective film formed on the substrate,
A protective film formed on the multilayer reflective film and made of a material containing ruthenium as a main component,
A tantalum-based material layer formed on the protective film and containing tantalum;
A ruthenium-based material layer formed on the tantalum-based material layer and containing ruthenium;
Wherein formed on the ruthenium-based material layer, as compared with the tantalum-based material layer faster etching rate to a chlorine-based gas, possess an etching mask film made of a tantalum-based materials including tantalum, and
The etching mask film is made of a material containing tantalum and nitrogen, and the content of nitrogen is 10 atomic% or more and 75 atomic% or less,
The reflection mask blank , wherein the etching mask film has an amorphous structure .   The etching mask film is composed of Ta alone, a TaB alloy containing Ta and B, a Ta alloy containing Ta and Hf, Zr, Pt or W, or N alone, the TaB, the TaB alloy or the Ta alloy. 2. The reflective mask blank according to claim 1, comprising a Ta-based compound to which H or C is added. On the surface in contact with the tantalum-based material layer as the surface of the protection film or as a part of the protection film, a diffusion prevention layer containing ruthenium and oxygen for suppressing interdiffusion with the tantalum-based material layer is provided. The reflective mask blank according to claim 1 or 2, wherein The reflective mask blank according to claim 3 , wherein the thickness of the diffusion preventing layer is 0.2 nm or more and 1.5 nm or less. The uppermost layer of the multilayer reflective film is silicon (Si), and has a silicon oxide layer containing silicon and oxygen between the uppermost layer and the protective film. 5. The reflective mask blank according to any one of items 4 to 5 . It is a manufacturing method of the reflective mask blank which manufactures the reflective mask blank according to any one of claims 1 to 5 ,
A reflective mask having a laminated structure in which the tantalum-based material layer and the ruthenium-based material layer are formed by sputtering, and are continuously formed from the start of film formation to the end of film formation without being exposed to the air. Blank manufacturing method. It is a manufacturing method of the reflective mask manufactured by the reflective mask blank according to any one of claims 1 to 5 ,
Forming a resist film pattern on the etching mask film, using the resist film pattern as a mask, etching with a chlorine-based etching gas to form an etching mask film pattern;
Using the etching mask film pattern as a mask, forming a ruthenium-based material layer pattern by etching with an etching gas containing oxygen gas,
Using the ruthenium-based material layer pattern as a mask, etching with a chlorine-based etching gas to form a tantalum-based material layer pattern,
A method for manufacturing a reflective mask, comprising: 8. The reflection type mask according to claim 7 , further comprising a step of removing the resist film pattern at the same time as a step of forming a ruthenium-based material layer pattern by etching with an etching gas containing an oxygen gas. Method. 9. The method according to claim 8 , further comprising the step of forming the tantalum-based material layer pattern using the ruthenium-based material layer pattern as a mask and simultaneously removing the etching mask film pattern. A reflection type mask manufactured by the method for manufacturing a reflection type mask according to any one of claims 7 to 9 is set in an exposure apparatus having an exposure light source that emits EUV light, and is formed on a substrate to be transferred. A method of transferring a transfer pattern to an existing resist film.

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