Method for manufacturing a substrate with a multilayer reflective film, a reflective mask blank and a method for manufacturing the same, and a method for manufacturing a reflective mask

Abstract

To provide a production method of a substrate with a multilayer reflection film capable of producing a reflective mask capable of correctly correcting drawing data based on flaw inspection.SOLUTION: There is provided a production method of a substrate with a multilayer reflection film which includes: a substrate; and a multilayer reflection film for reflecting EUV light onto the substrate. The method comprises: a step for performing first flaw inspection using a first wavelength to the substrate with a multilayer reflection film, for acquiring first flaw information; a step for using a second wavelength different from the first wavelength, performing second flaw inspection to the substrate with a multilayer reflection film, and acquiring second flaw information; and a step for collating the first flaw information with the second flaw information for determining whether there are same flaws or there are flaws which do not match, for acquiring third flaw information.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In recent years, in the semiconductor industry, with the high 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. In order to enable such fine pattern formation, EUV lithography, an exposure technique using extreme ultraviolet (hereinafter referred to as "EUV") light, has been regarded as promising. Here, EUV light refers to light in the wavelength band of the soft X-ray region or the vacuum ultraviolet region, specifically, light having a wavelength of about 0.2 to 100 nm. As a transfer mask used in this EUV lithography, a reflective mask has been proposed. Such a reflective mask is formed with a multilayer reflective film that reflects exposure light on a substrate, and an absorber film that absorbs exposure light is formed in a pattern on the multilayer reflective film.

[0003] The light incident on the reflective mask set in the exposure apparatus is absorbed in the part where the absorber film is present, and reflected by the multilayer reflective film in the part where the absorber film is absent. The reflected image is transferred onto the semiconductor substrate through the reflective optical system to form a mask pattern. As the above multilayer reflective film, for example, a film in which Mo and Si with a thickness of several nm are alternately laminated is known as one that reflects EUV light having a wavelength of 13 to 14 nm.

[0004] Patent Document 1 describes a method for manufacturing such a reflective mask blank, comprising a multilayer reflective film that reflects EUV light on a substrate and a laminated film formed on the multilayer reflective film. Specifically, Patent Document 1 describes a manufacturing method that includes the steps of: forming a substrate with a multilayer reflective film by depositing the multilayer reflective film on the substrate; performing a defect inspection on the substrate with the multilayer reflective film; depositing the laminated film on the multilayer reflective film of the substrate with the multilayer reflective film; forming a reference mark on the upper part of the laminated film that serves as a reference for the defect location in the defect information, thereby forming a reflective mask blank with the reference mark formed on it; and performing a defect inspection of the reflective mask blank using the reference mark as a reference.

[0005] Patent Document 2 describes a method for manufacturing a reflective mask blank, wherein at least one multilayer reflective film that reflects EUV light and an absorber film that absorbs EUV light are formed on a substrate. Specifically, Patent Document 2 describes a manufacturing method that includes the steps of: forming a substrate with a multilayer reflective film by depositing the multilayer reflective film on the substrate; performing a defect inspection on the substrate with the multilayer reflective film; depositing the absorber film on the multilayer reflective film of the substrate with the multilayer reflective film; forming a reflective mask blank in which an alignment region is formed in which the absorber film is removed from the outer edge region of the pattern formation region, exposing the multilayer reflective film in a region that includes a reference for defect information on the multilayer reflective film; and performing defect control of the reflective mask blank using the alignment region.

[0006] Furthermore, Patent Document 3 describes a multilayer reflective film substrate having a substrate and a multilayer reflective film formed on the substrate that reflects EUV light. Specifically, Patent Document 3 describes that the multilayer reflective film substrate is provided with reference marks that serve as a reference for the location of defects on the multilayer reflective film substrate, and the number of reference marks is determined in advance by a predetermined procedure. The predetermined procedure is described as follows: In (1) of the predetermined procedure, a defect inspection device having a first coordinate system acquires the first defect coordinate of a defect on another multilayer reflective film substrate having a plurality of reference marks, and the first reference mark coordinate of the reference marks. In (2) of the predetermined procedure, a coordinate measuring instrument having a second coordinate system acquires the second defect coordinate of the defect on the other multilayer reflective film substrate, and the second reference mark coordinate of the reference marks. In (3) of the predetermined procedure, a conversion coefficient for converting coordinates from the first coordinate system to the second coordinate system is calculated based on the first reference mark coordinate and the second reference mark coordinate. In step (4) of the prescribed procedure, the first defect coordinate obtained by the defect inspection device in step (1) is converted to a third defect coordinate based on the second coordinate system using the conversion coefficient calculated in step (3) above. In step (5) of the prescribed procedure, the value of 3σ is determined as the difference between the second defect coordinate obtained by the coordinate measuring instrument in step (2) above and the third defect coordinate converted in step (4) above. In step (6) of the prescribed procedure, the correspondence between the number of reference marks and 3σ is obtained. In step (7) of the prescribed procedure, the number of reference marks for which the value of 3σ is less than 50 nm is determined.

[0007] Furthermore, Patent Documents 4 and 5 describe substrates for mask blanks used in lithography. Patent Documents 4 and 5 also describe the use of a highly sensitive defect inspection system with an inspection light source wavelength of 193 nm (KLA-Tencor's "Teron600 series") and a highly sensitive defect inspection system with an inspection light source wavelength of 266 nm (Lasertec's "MAGICS M7360") to inspect defects in substrates with multilayer reflective coatings. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2014 / 129527 [Patent Document 2] International Publication No. 2017 / 169973 [Patent Document 3] International Publication No. 2020 / 95959 [Patent Document 4] International Publication No. 2014 / 104276 [Patent Document 5] International Publication No. 2015 / 046303 [Overview of the project] [Problems that the invention aims to solve]

[0009] A technique has been proposed to mitigate defects (Defect Mitigation Technology, hereinafter referred to as "DM technology") by correcting the drawing data based on the defect data of the mask blank and the device pattern data so that an absorber pattern is formed in the areas where defects exist. To realize DM technology, for example, in a reflective mask blank in which an absorber film is formed on a multilayer reflective film, when drawing a pattern on the resist film formed on the absorber film using an electron beam lithography system, the electron beam lithography system also detects reference marks with an electron beam. In DM technology, a pattern is drawn on the resist film based on the corrected and modified drawing data, which is based on the reference points detected by the electron beam lithography system.

[0010] On the other hand, with the rapid miniaturization of patterns in lithography using EUV light, the defect size required for reflective EUV masks is also becoming smaller year by year. In order to detect such minute defects, the wavelength of the inspection light source used for defect inspection is approaching the wavelength of the exposure light (e.g., EUV light).

[0011] For inspecting defects in EUV masks, EUV mask blanks (the original plates for EUV masks), multilayer reflective substrates, and substrates, popular options include the Lasertec MAGICS M7360 EUV exposure mask / substrate / blank defect inspection system with an inspection light source wavelength of 266 nm, and the KLA-Tencor Teron 600 series (e.g., Teron 610) EUV mask / blank defect inspection system with an inspection light source wavelength of 193 nm. In recent years, ABI (Actinic Blank Inspection) systems with an inspection light source wavelength of 13.5 nm (the same as the exposure light source wavelength) have been proposed.

[0012] However, with defect inspection equipment using inspection light source wavelengths of 266 nm or 193 nm, it is difficult to detect minute defects. On the other hand, even when performing high-precision defect inspection of reflective mask blanks using an ABI device with an inspection light source wavelength of 13.5 nm, it is difficult to identify all defects and dimensions. Therefore, problems may arise when correcting drawing data using DM technology.

[0013] Therefore, the present invention aims to provide a method for manufacturing a reflective mask that can more accurately correct drawing data based on defect inspection.

[0014] Furthermore, the present invention aims to provide a substrate with a multilayer reflective film for manufacturing a reflective mask that can more accurately correct drawing data based on defect inspection, and a method for manufacturing a reflective mask blank. [Means for solving the problem]

[0015] To solve the above problems, the present invention has the following configuration.

[0016] (Composition 1) Configuration 1 of the present invention is a method for manufacturing a substrate with a multilayer reflective film, which includes a substrate and a multilayer reflective film that reflects EUV light on the substrate, A step of performing a first defect inspection on the substrate with the multilayer reflective film using a first wavelength and obtaining first defect information; A step of performing a second defect inspection on the substrate with the multilayer reflective film using a second wavelength different from the first wavelength and obtaining second defect information; A method for manufacturing a substrate with a multilayer reflective film, comprising a step of obtaining third defect information by collating the first defect information and the second defect information to determine the presence or absence of mismatched defects and matched defects.

[0017] (Configuration 2) Configuration 2 of the present invention is a method for manufacturing a substrate with a multilayer reflective film according to Configuration 1, characterized in that the second wavelength is a wavelength comparable to the exposure wavelength, and the first wavelength is a wavelength longer than the second wavelength.

[0018] (Configuration 3) In Configuration 3 of the present invention, the substrate with the multilayer reflective film includes a reference mark RM. The first defect information includes a first mark coordinate RM1 and a first defect coordinate of the reference mark RM. The second defect information includes a second mark coordinate RM2 and a second defect coordinate of the reference mark RM. The step of obtaining the third defect information is based on converting the first defect coordinate based on the first mark coordinate RM1 to a coordinate based on the second mark coordinate RM2 based on the relative position coordinate between the first mark coordinate RM1 and the second mark coordinate RM2. This is a method for manufacturing a substrate with a multilayer reflective film according to Configuration 1 or 2.

[0019] (Configuration 4) In Configuration 4 of the present invention, when there is the mismatched defect between the first defect information and the second defect information, the mismatched defect is regarded as a defect in a first defect map based on the first mark coordinate RM1. When there is such a matching defect between the first defect information and the second defect information, the matching defect is defined as a defect in the second defect map based on the second mark coordinates RM2. This is a method for manufacturing a substrate with a multilayer reflective film according to any one of Configurations 1 to 3.

[0020] (Configuration 5) In Configuration 5 of the present invention, when there is such a non - matching defect between the first defect information and the second defect information, a step of specifying a first non - matching defect detected only in the first defect inspection and a second non - matching defect detected only in the second defect inspection is included. The method for manufacturing a substrate with a multilayer reflective film further includes a step of performing a third defect inspection different from the first defect inspection and the second defect inspection on the substrate with the multilayer reflective film. The third defect inspection includes measuring at least one defect dimension among the matching defect and the first non - matching defect. The method for manufacturing a substrate with a multilayer reflective film according to any one of Configurations 1 to 4 includes adding the defect dimension measured in the third defect inspection to the third defect information.

[0021] (Configuration 6) Configuration 6 of the present invention is a method for manufacturing a substrate with a multilayer reflective film according to any one of Configurations 1 to 5, characterized in that the substrate with a multilayer reflective film further includes a protective film on the multilayer reflective film.

[0022] (Configuration 7) Configuration 7 of the present invention is a reflective mask blank characterized by having a substrate with a multilayer reflective film manufactured by a method for manufacturing a substrate with a multilayer reflective film according to any one of Configurations 1 to 6, and an absorber film formed on the substrate with the multilayer reflective film.

[0023] (Configuration 8) Configuration 8 of the present invention is a reflective mask blank according to Configuration 7, characterized in that the absorber film includes a second reference mark FM formed on the absorber film and a transferred reference mark RM'to which the reference mark RM is transferred on the absorber film.

[0024] (Composition 9) Configuration 9 of the present invention includes the step of identifying a first mismatch defect that is detected only in the first defect inspection and a second mismatch defect that is detected only in the second defect inspection, if there is a mismatch defect between the first defect information and the second defect information of the reflective mask blank of configuration 7 or 8, The process further includes a step of performing a third defect inspection on a reflective mask blank at a third wavelength different from the first and second wavelengths, The third defect inspection includes measuring the dimensions of at least one of the matching defects and the first mismatched defects transferred to the absorber membrane. A method for manufacturing a reflective mask blank, characterized in that the defect dimensions measured in the third defect inspection are added to the third defect information.

[0025] (Composition 10) Configuration 10 of the present invention is a method for manufacturing a reflective mask, characterized by patterning the absorbent film of a reflective mask blank manufactured by the method for manufacturing a reflective mask blank of configuration 7 or 8, or configuration 9, to form an absorbent pattern. [Effects of the Invention]

[0026] The present invention provides a method for manufacturing a reflective mask that allows for more accurate correction of drawing data based on defect inspection.

[0027] Furthermore, the present invention provides a substrate with a multilayer reflective film for manufacturing a reflective mask that can more accurately correct drawing data based on defect inspection, and a method for manufacturing a reflective mask blank. [Brief explanation of the drawing]

[0028] [Figure 1] This is a schematic cross-sectional view of an example of a substrate with a multilayer reflective film according to this embodiment. [Figure 2] This is a schematic cross-sectional view of another example of a substrate with a multilayer reflective film according to this embodiment. [Figure 3] This is a schematic cross-sectional view of an example of a reflective mask blank according to this embodiment. [Figure 4] This is a process diagram showing the manufacturing method of the reflective mask of this embodiment in a schematic cross-sectional view. [Figure 5] This is a schematic plan view showing an example of a substrate with a multilayer reflective film according to this embodiment. [Figure 6] This is a schematic plan view showing another example of the multilayer reflective film substrate of this embodiment. [Figure 7] This is a schematic plan view showing an example of a reflective mask blank of this embodiment. [Figure 8] This is a schematic plan view showing an example of the shape of the reference mark (second reference mark FM). [Modes for carrying out the invention]

[0029] The embodiments of the present invention will be described in detail below with reference to the drawings. Note that the following embodiments are intended to illustrate the present invention in detail and do not limit the present invention to their scope.

[0030] Figure 1 shows a schematic cross-sectional view of an example of a multilayer reflective substrate 110 according to this embodiment. This embodiment is a method for manufacturing a multilayer reflective substrate 110, which includes a substrate 1 and a multilayer reflective film 5 that reflects EUV light on the substrate 1.

[0031] As shown in Figure 1, the multilayer reflective substrate 110 of this embodiment includes a multilayer reflective film 5 on a substrate 1. The multilayer reflective film 5 is a film for reflecting exposure light and consists of a multilayer film in which low refractive index layers and high refractive index layers are alternately stacked. The multilayer reflective substrate 110 of this embodiment may include a back surface conductive film 2 on the back surface of the substrate 1 (the main surface opposite to the main surface on which the multilayer reflective film 5 is formed).

[0032] Figure 2 shows a schematic cross-sectional view of another example of the multilayer reflective substrate 110 of this embodiment. In the example shown in Figure 2, the multilayer reflective substrate 110 includes a protective film 6.

[0033] A reflective mask blank 100 can be manufactured using the multilayer reflective film substrate 110 of this embodiment. Figure 3 shows a schematic cross-sectional view of an example of the reflective mask blank 100 of this embodiment. The reflective mask blank 100 further includes an absorbent film 7.

[0034] Specifically, the reflective mask blank 100 of this embodiment has an absorber film 7 on the outermost surface of the substrate 110 with a multilayer reflective film (for example, the surface of the multilayer reflective film 5 or protective film 6). By using the reflective mask blank 100 of this embodiment, a reflective mask 200 can be obtained that can correct drawing data based on defect inspection more accurately.

[0035] In this specification, "multilayer reflective substrate 110" refers to a substrate 1 on which a multilayer reflective film 5 is formed. Figures 1 and 2 show examples of schematic cross-sectional views of a multilayer reflective substrate 110. Note that the multilayer reflective substrate 110 also includes substrates on which thin films other than the multilayer reflective film 5, such as a protective film 6 and / or a back surface conductive film 2, are formed.

[0036] In this specification, "reflective mask blank 100" refers to a substrate 110 with a multilayer reflective film on which an absorber film 7 is formed. The reflective mask blank 100 also includes a substrate 110 with a multilayer reflective film on which a thin film other than the absorber film 7 (for example, an etching mask film and / or a resist film 8, etc.) is further formed.

[0037] In this specification, "placing (forming) an absorber film 7 on a multilayer reflective film 5" means not only that the absorber film 7 is placed (formed) in contact with the surface of the multilayer reflective film 5, but also that there is another film between the multilayer reflective film 5 and the absorber film 7. The same applies to other films. Furthermore, in this specification, for example, "placing film A in contact with the surface of film B" means that film A and film B are placed in direct contact with each other without any other film in between.

[0038] <Multilayer reflective coating substrate 110> The substrate 1 and each thin film that constitute the multilayer reflective substrate 110 of this embodiment will be described below.

[0039] <<Circuit Board 1>> In the multilayer reflective substrate 110 of this embodiment, it is necessary to prevent distortion of the absorber pattern 7a due to heat during EUV exposure. Therefore, the substrate 1 preferably has a low thermal expansion coefficient in the range of 0 ± 5 ppb / °C. Examples of materials having a low thermal expansion coefficient in this range include SiO2-TiO2 glass and multi-component glass ceramics.

[0040] The first main surface of the substrate 1 on the side where the transfer pattern (corresponding to the absorber pattern 7a described later) is formed is surface-processed to achieve a predetermined flatness, at least from the viewpoint of obtaining pattern transfer accuracy and positional accuracy. In the case of EUV exposure, the flatness of the 132 mm × 132 mm area of ​​the main surface of the substrate 1 on the side where the transfer pattern is formed is preferably 0.1 μm or less, more preferably 0.05 μm or less, and even more preferably 0.03 μm or less. The second main surface (back side) on the side opposite to the side where the absorber film 7 is formed is the surface that is electrostatically chucked when set in the exposure apparatus. The second main surface has a flatness of 0.1 μm or less in a 142 mm × 142 mm area, more preferably 0.05 μm or less, and even more preferably 0.03 μm or less.

[0041] Furthermore, the surface smoothness of the substrate 1 is also an extremely important factor. The surface roughness of the first main surface on which the transfer absorber pattern 7a is formed is preferably 0.15 nm or less in terms of root mean square roughness (Rms), and more preferably 0.10 nm or less in terms of Rms. Surface smoothness can be measured using an atomic force microscope.

[0042] Furthermore, the substrate 1 is preferably made of high rigidity in order to prevent deformation due to film stress of the film (such as the multilayer reflective film 5) formed on the substrate 1. In particular, the substrate 1 is preferably made of a high Young's modulus of 65 GPa or more.

[0043] <<Multilayer reflective film 5>> The multilayer reflective film 5 provides the reflective mask 200 with the function of reflecting EUV light. The multilayer reflective film 5 has a multilayer structure in which each layer, mainly composed of elements with different refractive indices, is periodically stacked.

[0044] Generally, a multilayer film is used as the multilayer reflective film 5, in which thin films of light elements or compounds thereof, which are high refractive index materials (high refractive index layers), and thin films of heavy elements or compounds thereof, which are low refractive index materials, are alternately stacked for about 40 to 60 periods. The multilayer film may be stacked in multiple periods, with a high refractive index layer / low refractive index layer stacking structure, where the high refractive index layer and the low refractive index layer are stacked in this order from the substrate 1 side, as one period. Alternatively, the multilayer film may be stacked in multiple periods, with a low refractive index layer / high refractive index layer stacking structure, where the low refractive index layer and the high refractive index layer are stacked in this order from the substrate 1 side, as one period. It is preferable that the outermost layer of the multilayer reflective film 5, i.e., the surface layer of the multilayer reflective film 5 opposite the substrate 1, be a high refractive index layer. In the above-described multilayer film, when multiple periods are stacked with a high refractive index layer / low refractive index layer stacking structure, where the high refractive index layer and the low refractive index layer are stacked in this order from the substrate 1, the uppermost layer becomes a low refractive index layer. In this case, if the low refractive index layer constitutes the outermost surface of the multilayer reflective film 5, it will be easily oxidized, and the reflectivity of the reflective mask 200 will decrease. Therefore, it is preferable to further form a high refractive index layer on the uppermost low refractive index layer to form a multilayer reflective film 5. On the other hand, in the above-described multilayer film, if a low refractive index layer and a high refractive index layer are stacked in this order from the substrate 1 side, and multiple periods of stacking are performed with this low refractive index layer / high refractive index layer structure as one period, the uppermost layer will be the high refractive index layer, so it is fine as is.

[0045] In this embodiment, a layer containing silicon (Si) is used as the high refractive index layer. The Si-containing material may be Si alone, or a Si compound containing boron (B), carbon (C), nitrogen (N), and oxygen (O). By using the Si-containing layer as the high refractive index layer, a reflective mask 200 for EUV lithography with excellent EUV light reflectivity can be obtained. In this embodiment, a glass substrate is preferably used as the substrate 1. Si also exhibits excellent adhesion to the glass substrate. Furthermore, as the low refractive index layer, a metal element selected from molybdenum (Mo), ruthenium (Ru), rhodium (Rh), and platinum (Pt), or an alloy thereof, can be used. For example, as the multilayer reflective film 5 for EUV light with a wavelength of 13 nm to 14 nm, a Mo / Si periodic multilayer film is preferably used, in which Mo films and Si films are alternately stacked for approximately 40 to 60 periods. Alternatively, the uppermost high-refractive-index layer of the multilayer reflective film 5 may be formed of silicon (Si), and a silicon oxide layer containing silicon and oxygen may be formed between the uppermost layer (Si) and the Ru-based protective film 6. This can improve the mask's resistance to washing.

[0046] The reflectivity of such a multilayer reflective film 5 on its own is usually 65% ​​or higher, with an upper limit of usually 73%. The film thickness and period of each constituent layer of the multilayer reflective film 5 can be appropriately selected according to the exposure wavelength, and are selected to satisfy Bragg's law of reflection. Multiple high-refractive-index layers and multiple low-refractive-index layers exist in the multilayer reflective film 5. The film thicknesses of the high-refractive-index layers and the low-refractive-index layers do not have to be the same. In addition, the film thickness of the Si layer on the outermost surface of the multilayer reflective film 5 can be adjusted within a range that does not reduce the reflectivity. The film thickness of the outermost Si (high-refractive-index layer) can be from 3 nm to 10 nm.

[0047] The method for forming the multilayer reflective film 5 is known in the art. For example, it can be formed by depositing each layer of the multilayer reflective film 5 using an ion beam sputtering method. In the case of the Mo / Si periodic multilayer film described above, for example, a Si film with a thickness of about 4 nm is first deposited on the substrate 1 using a Si target by an ion beam sputtering method. Then, a Mo film with a thickness of about 3 nm is deposited using a Mo target. These Si and Mo films constitute one period, and the multilayer reflective film 5 is formed by stacking 40 to 60 periods (the outermost layer is the Si layer). Furthermore, it is preferable to form the multilayer reflective film 5 by supplying krypton (Kr) ion particles from an ion source and performing ion beam sputtering during the deposition of the multilayer reflective film 5. The multilayer reflective film 5 is preferably about 40 periods in terms of improving reflectivity by increasing the number of stacking periods and reducing throughput by increasing the number of processes. However, the number of stacking periods of the multilayer reflective film 5 is not limited to 40 periods; for example, it may be 60 periods. While a 60-cycle design requires more processes than a 40-cycle design, it allows for a higher reflectivity to EUV light.

[0048] <<Protective film 6>> In the multilayer reflective substrate 110 of this embodiment, it is preferable to have a protective film 6 on the multilayer reflective film 5, as shown in Figure 2. By forming the protective film 6 on the multilayer reflective film 5, damage to the surface of the multilayer reflective film 5 can be suppressed when manufacturing the reflective mask 200 using the multilayer reflective substrate 110. As a result, the reflectivity characteristics of the resulting reflective mask 200 with respect to EUV light are improved.

[0049] The protective film 6 is formed on the multilayer reflective film 5 to protect it from dry etching and cleaning during the manufacturing process of the reflective mask 200, which will be described later. The protective film 6 also serves to protect the multilayer reflective film 5 during black defect correction of the mask pattern using an electron beam (EB). Here, Figure 2 shows the case where the protective film 6 is a single layer. However, the protective film 6 may be a two-layer laminated structure, or a three-layer laminated structure, in which the bottom and top layers are made of a material containing Ru, for example, and a metal or alloy other than Ru is interposed between the bottom and top layers. The protective film 6 is formed from a material mainly composed of ruthenium, for example. Materials containing ruthenium as the main component include elemental ruthenium (Ru), ruthenium alloys containing at least one metal selected from titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), zirconium (Zr), yttrium (Y), boron (B), lanthanum (La), cobalt (Co), and rhenium (Re), and materials containing nitrogen.

[0050] The Ru content of the Ru alloy used in the protective film 6 is 50 atomic% or more and less than 100 atomic%, preferably 80 atomic% or more and less than 100 atomic%, and more preferably 95 atomic% or more and less than 100 atomic%. In particular, when the Ru content of the Ru alloy is 95 atomic% or more and less than 100 atomic%, it becomes possible to suppress the diffusion of constituent elements (e.g., silicon) of the multilayer reflective film 5 into the protective film 6. Furthermore, in this case, the protective film 6 can combine functions such as mask cleaning resistance, etching stopper function when the absorber film 7 is etched, and prevention of changes in the multilayer reflective film 5 over time, while ensuring sufficient reflectivity of EUV light.

[0051] The thickness of the protective film 6 is not particularly limited as long as it can perform its function as a protective film 6. From the viewpoint of EUV light reflectance, the thickness of the protective film 6 is preferably 1.0 nm to 8.0 nm, more preferably 1.5 nm to 6.0 nm.

[0052] As for the method of forming the protective film 6, any known film formation method can be used without particular limitation. Specific examples of methods for forming the protective film 6 include sputtering and ion beam sputtering.

[0053] <Manufacturing method for a multilayer reflective substrate 110> Next, the manufacturing method for the multilayer reflective film substrate 110 of this embodiment will be described.

[0054] In the manufacturing method of the multilayer reflective substrate 110 of this embodiment, first, the substrate 1 described above is prepared, and the multilayer reflective film 5 described above is formed on the first main surface of the substrate 1 (see Figure 1). If necessary, the protective film 6 described above can be formed on the multilayer reflective film 5 (see Figure 2). Furthermore, in the manufacturing method of the multilayer reflective substrate 110 of this embodiment, a back surface conductive film 2 can be formed on the back surface of the substrate 1 (the main surface opposite to the main surface on which the multilayer reflective film 5 is formed) (see Figure 2).

[0055] <<Step to obtain the first defect information>> The manufacturing method for the multilayer reflective substrate 110 of this embodiment includes a step of performing a first defect inspection on the main surface of the multilayer reflective substrate 110 on which the multilayer reflective film 5 is formed, using a first wavelength, and acquiring first defect information. In this specification, "defect information" refers to information about structures that may be evaluated as defects detected in defect inspection, such as data including location information, and also includes information about structures that are not necessarily treated as defects.

[0056] Furthermore, as mentioned above, the thickness of the protective film 6 is at most 8 nm, making it extremely thin. Therefore, even when the protective film 6 is formed on top of the multilayer reflective film 5, defects in the multilayer reflective film 5 can be detected by defect inspection. The same applies to other defect inspections.

[0057] The "first wavelength" used in the first defect inspection is a different wavelength from the second wavelength used for the second defect inspection, which will be described later. The first wavelength can be, for example, 365 nm, 355 nm, 266 nm, 213 nm, and 193 nm. If the first wavelength is 365 nm, the defect inspection device for the first defect inspection can be, for example, the KLA-Tencor coordinate measuring instrument "LMS-IPRO4" which performs coordinate measurement with a 365 nm laser. If the first wavelength is 266 nm or 355 nm, the defect inspection device for the first defect inspection can be, for example, the Lasertec EUV exposure mask / substrate / blank defect inspection device "MAGICS M7360" or "MAGICS M8650" which have an inspection light source wavelength of 266 nm or 355 nm. When the first wavelength is 213 nm, the Lasertec MAGICS M9650 EUV exposure mask / substrate / blank defect inspection system, which has an inspection wavelength of 213 nm, can be used. When the first wavelength is 193 nm, the KLA-Tencor Teron 600 series EUV mask / blank defect inspection system, such as the Teron 610, which has an inspection light source wavelength of 193 nm, or the Carl Zeiss PROVE coordinate measuring instrument, which performs coordinate measurement with a 193 nm laser, can be used. By performing defect inspection with the defect inspection system or measuring the defect coordinates with the coordinate measuring instrument, information regarding the location and dimensions of defects in the multilayer reflective substrate 110 (first defect information) can be obtained.

[0058] For the first defect inspection, it is preferable to use the "MAGICS M8650" mask / substrate / blank defect inspection device, which has a first wavelength of 355 nm, because it can perform defect inspection with high accuracy.

[0059] The multilayer reflective substrate 110 preferably includes a reference mark RM (e.g., a dot mark). The reference mark RM is sometimes called an AM (alignment mark). The AM is a mark that can be used as a reference for defect coordinates when inspecting defects on the multilayer reflective substrate 110 with a defect inspection device. However, the AM is not directly used when drawing patterns with an electron beam lithography device. The shape of the reference mark RM can be, for example, a dot mark, a roughly cross-shaped mark, or a square mark. The shape of the reference mark RM is preferably a dot mark or a roughly cross-shaped mark, and more preferably a circular dot mark, because it is easy to detect by a defect inspection device. Figure 5 shows an example in which a circular dot mark, the reference mark 20, is formed as the reference mark RM. By having a reference mark RM on the multilayer reflective substrate 110, the position coordinates of defects obtained by defect inspection can be associated with the position coordinates of the reference mark RM. Therefore, the location of defects on the multilayer reflective substrate 110 can be identified more accurately.

[0060] Preferably, the first defect information includes the first mark coordinate RM1 of the reference mark RM and the first defect coordinate.

[0061] In this specification, the position coordinates of the reference mark RM measured in the first defect inspection may be referred to as the "first mark coordinates RM1". The first defect information may include the first mark coordinates RM1 of the reference mark RM. By associating the position coordinates of the reference mark RM with the location of the defect on the multilayer reflective substrate 110, the location of the defect measured in the first defect inspection can be identified more accurately.

[0062] Figure 5 is a plan view of the multilayer reflective substrate 110 of this embodiment. In the example shown in Figure 5, two reference marks 20 are formed near each of the four corners of the substantially rectangular multilayer reflective substrate 110, as an example of a reference mark RM. The reference marks 20 are marks used as a reference for the location of defects in defect information. Figure 5 shows an example in which eight reference marks 20 are formed. The reference marks 20 need to be placed at least three of the four corners. Therefore, the number of reference marks 20 should be three or more, and preferably four or more. It is also preferable that one reference mark 20 be placed at each of the four corners, and more preferably two at each of the four corners. Furthermore, it is necessary that three or more reference marks 20 be placed on at least two axes.

[0063] In the multilayer reflective film substrate 110 shown in Figure 5, if the size of the substrate 1 is 152 mm × 152 mm, an absorber pattern 7a is formed in the pattern formation region inside the dashed line A (a region of 132 mm × 132 mm) when manufacturing the reflective mask 200. An absorber pattern 7a is not formed in the region outside the dashed line A when manufacturing the reflective mask 200. Preferably, the reference mark 20 is formed in the region where the absorber pattern 7a is not formed, i.e., above the dashed line A or in the region outside the dashed line A.

[0064] As shown in Figure 5, the reference mark 20 has a circular dot shape. The diameter of the reference mark 20 having a circular dot shape is, for example, 200 nm or more and 10 μm or less. Figure 5 shows an example of a reference mark 20 having a circular dot shape, but the shape of the reference mark 20 is not limited to this. The shape of the reference mark 20 may be, for example, roughly cross-shaped, roughly L-shaped in plan view, triangular, or square.

[0065] The multilayer reflective substrate 110 of this embodiment may further have a reference mark CM that differs in shape or dimensions from the reference mark RM described above. Figure 6 shows a multilayer reflective substrate 110 having a roughly cross-shaped reference mark 22 (reference mark CM) along with a circular dot-shaped reference mark 20 (reference mark RM). It is preferable that the reference mark CM is a roughly cross-shaped reference mark 22. When the multilayer reflective substrate 110 includes a reference mark CM, the first defect information and / or second defect information may further include the mark coordinates CM1 of the reference mark CM. The dimensions (size and depth) of the reference mark CM can be adjusted so that the reference mark CM is transferred to the absorber film 7 and the resist film 8 when the absorber film 7 and the resist film 8 are formed on the multilayer reflective substrate 110. Such a reference mark CM can be used as a second reference mark FM (reference mark 24 shown in Figure 7). The reference mark CM can also be used as an AM (alignment mark). The presence of a reference mark CM in the multilayer reflective substrate 110 makes it possible to convert the defect map (a map showing defect coordinates) based on the first and second defect inspections into a defect map based on the second reference mark FM.

[0066] The cross-sectional shape of the reference mark 20 can be, for example, concave. "Concave" means that when viewing the cross-section of the multilayer reflective substrate 110 (a cross-section perpendicular to the main surface of the multilayer reflective substrate 110), the reference mark 20 is formed to be recessed downwards, for example, in a stepped or curved shape. The depth D of the concave reference mark 20 is preferably 30 nm or more, and more preferably 40 nm or more. The depth D of the reference mark 20 can also be the depth to which the substrate 1 is exposed. Depth D means the vertical distance from the surface of the multilayer reflective substrate 110 to the deepest point at the bottom of the reference mark 20.

[0067] The method for forming the reference mark 20 is not particularly limited. The reference mark 20 can be formed, for example, on the surface of the substrate 110 with a multilayer reflective film by laser processing. In this case, the reference mark 20 can be formed after the multilayer reflective film 5 is deposited, and then the protective film 6 can be deposited. Alternatively, the multilayer reflective film 5 and the protective film 6 can be deposited first, and then the reference mark 20 can be formed. The conditions for laser processing are, for example, as follows. Laser type (wavelength): Ultraviolet to visible light range. For example, a semiconductor laser with a wavelength of 405 nm. Laser output: 1-120 mW Scanning speed: 0.1~20 mm / s Pulse frequency: 1~100 MHz Pulse width: 3ns~1000s

[0068] The laser used to laser-process the reference mark 20 may be a continuous wave or a pulsed wave. When using a pulsed wave, it is possible to make the width W of the reference mark 20 smaller, even if the depth D of the reference mark 20 is the same as when using a continuous wave. Therefore, when using a pulsed wave, it is possible to form a reference mark 20 with higher contrast compared to a continuous wave, making it easier to detect by defect inspection equipment and electron beam lithography equipment.

[0069] The method for forming the reference mark 20 is not limited to lasers. The reference mark 20 can be formed by methods such as photolithography, FIB (focused ion beam), processing marks by scanning with a diamond needle, indentation with a micro-indenter, and imprinting.

[0070] The cross-sectional shape of the reference mark 20 is not limited to a concave shape. For example, the cross-sectional shape of the reference mark 20 may be convex, protruding upward. When the cross-sectional shape of the reference mark 20 is convex, it can be formed by partial film deposition using methods such as FIB or sputtering. The height H of the convex reference mark 20 is preferably 30 nm or more, and more preferably 40 nm or more. Height H refers to the vertical distance from the surface of the multilayer reflective film substrate 110 to the highest position of the reference mark 20.

[0071] When a reference mark 20 is formed on a multilayer reflective substrate 110, it is necessary to acquire the coordinates of the reference mark 20 (reference mark RM) (mark coordinate RM1) and the coordinates of the defect with high precision using a defect inspection device. Therefore, the reference mark 20 formed on the multilayer reflective substrate 110 must have a high enough contrast to be detectable by a defect inspection device or coordinate measuring instrument.

[0072] <<Step to obtain second defect information>> The manufacturing method for the multilayer reflective substrate 110 of this embodiment includes a step of performing a second defect inspection on the main surface of the multilayer reflective substrate 110 on which the multilayer reflective film 5 is formed, using a second wavelength different from the first wavelength, and acquiring second defect information.

[0073] The "second wavelength" is the wavelength used for the second defect inspection and is different from the first wavelength used for the first defect inspection described above. In the manufacturing method of the multilayer reflective film substrate 110 of this embodiment, the second wavelength is preferably a wavelength of approximately the same magnitude as the exposure wavelength. A "wavelength of approximately the same magnitude as the exposure wavelength" can be a wavelength of λ ± 1 nm, where λ is the exposure wavelength. For example, if the exposure wavelength λ = 13.5 nm, the second wavelength can be a wavelength of 12.5 to 14.5 nm. Specifically, an ABI (Actinic Blank Inspection) device can be used as the device for the second defect inspection, in which the inspection light source wavelength is the same as the exposure light source wavelength of 13.5 nm. By having the second wavelength be of approximately the same magnitude as the exposure wavelength, minute defects can be detected.

[0074] Preferably, the first wavelength is longer than the second wavelength. Specifically, a wavelength of approximately 193 to 365 nm can be used as the first wavelength for the first defect inspection, and a wavelength of 12.5 to 14.5 nm can be used as the second wavelength for the second defect inspection. By having a first wavelength longer than the second wavelength, it may be possible to detect defects different from those that can be detected at the second wavelength.

[0075] In the second defect inspection, a second wavelength is used to perform the defect inspection and measure the second defect coordinates. Because the second defect inspection uses a different wavelength than the first defect inspection, the defect coordinates obtained in the second defect inspection (second defect coordinates) may differ from those of the first defect, even for the same defect. Also, defects that were not detected in the first defect inspection may be detected in the second defect inspection. Furthermore, defects that were detected in the first defect inspection may not be detected in the second defect inspection. In addition, the dimensions of a defect detected in the first defect inspection may differ from the dimensions of the defect detected in the second defect inspection. Therefore, by performing the second defect inspection after the first defect inspection and comparing the information obtained from the two defect inspections, more accurate defect information can be obtained.

[0076] The second defect information preferably includes the second mark coordinate RM2 of the reference mark RM and the second defect coordinate.

[0077] In this specification, the position coordinates of the reference mark RM (for example, the reference mark 20 shown in Figure 5) measured in the second defect inspection may be referred to as the "second mark coordinates RM2". The reference mark RM is the same as that described in the first defect inspection above. The second defect information may include the second mark coordinates RM2 of the reference mark RM. By associating the position coordinates of the reference mark RM with the location of the defect on the multilayer reflective substrate 110, the location of the defect measured in the second defect inspection can be identified more accurately.

[0078] Furthermore, in another embodiment of this design, the first defect information and the second defect information may differ in their height-direction information.

[0079] In other words, another embodiment is a method for manufacturing a substrate 110 with a multilayer reflective film, which includes a substrate 1 and a multilayer reflective film 5 that reflects EUV light on the substrate 1. Another embodiment comprises the steps of performing a first defect inspection on the multilayer reflective film substrate 110 at a first wavelength and obtaining first defect information, and performing a second defect inspection on the multilayer reflective film substrate 110 at a second wavelength different from the first wavelength and obtaining second defect information. In another embodiment, the first defect information and the second defect information differ in their height direction information. The height direction is the direction perpendicular to the main surface of the substrate 1. The height direction information means the height direction location of the defect and / or the height direction size of the defect. For example, the first defect information may include the coordinates and / or height direction size of a defect located near the surface of the multilayer reflective film 5, and the second defect information may include the coordinates and / or height direction size of a defect located inside the multilayer reflective film 5.

[0080] <<Step to obtain third defect information>> The manufacturing method for the multilayer reflective film substrate 110 of this embodiment includes a step of obtaining third defect information by comparing first defect information and second defect information to determine the presence or absence of mismatched defects and matching defects. In this specification, "third defect information" refers to data containing defect information obtained based on the first and second defect information, and the third defect information also includes defect information obtained by a third defect inspection performed based on the first and second defect information.

[0081] Because the first and second defect inspections use different wavelengths, defects that were not detected in the first inspection may be detected in the second inspection. Conversely, defects that were detected in the first inspection may not be detected in the second inspection. Also, the same defects as those detected in the first inspection may be detected in the second inspection. Furthermore, the defect coordinates obtained in the second inspection (second defect coordinates) may differ in size from those obtained in the first defect coordinates, even for the same defect. Therefore, in order to obtain third defect information, the first and second defect information are compared to determine the presence or absence of mismatched and matching defects. For example, based on the first mark coordinate RM1 of the first defect inspection and the second mark coordinate RM2 of the second defect inspection, the coordinate system of the first defect inspection is affine-transformed to the coordinate system of the second defect inspection. The distance between the affine-transformed first and second defect coordinates, and a value calculated considering the coordinate accuracy of the first and second defect inspections (defect distance), are compared with a value calculated based on the dimensions of the first and second defects (defect length, i.e., distance). If the defect distance is shorter than the defect length, it can be determined to be a matching defect. As a result, information such as the position coordinates of the defects can be identified more accurately.

[0082] In this specification, "inconsistent defect" refers to a defect that was detected in the first defect inspection but not in the second defect inspection, or a defect that was detected in the second defect inspection but not in the first defect inspection.

[0083] Furthermore, in this specification, "matching defect" refers to a defect that was detected in the first defect inspection and was also detected in the second defect inspection.

[0084] In the step of acquiring the third defect information, it is preferable to acquire the third defect information by converting the first defect coordinates, which are based on the first mark coordinate RM1, to coordinates based on the second mark coordinate RM2, based on the relative position coordinates of the first mark coordinate RM1 and the second mark coordinate RM2. When acquiring the third defect information, the first defect coordinates, which are the coordinate system of the first defect inspection, can be converted to the coordinate system of the second defect inspection.

[0085] In the manufacturing method of the multilayer reflective film substrate 110 of this embodiment, if there is a discrepancy defect between the first defect information and the second defect information, it is preferable that the discrepancy defect be a defect in the first defect map based on the first mark coordinate RM1. The first defect map refers to a defect map that shows the coordinates of defects based on the first mark coordinate RM1 (the position coordinate of the reference mark RM measured in the first defect inspection).

[0086] In the second defect inspection, which uses a second wavelength shorter than the first wavelength, defects near the surface of the anti-reflective coating may not be detected. In such cases, the first defect information obtained by the first defect inspection using the first wavelength can be used as the defect information for the discrepancy, and this can be used as the third defect information.

[0087] In the manufacturing method of the multilayer reflective film substrate 110 of this embodiment, if there is a matching defect between the first defect information and the second defect information, it is preferable that the matching defect be a defect in the second defect map based on the second mark coordinate RM2. The second defect map refers to a defect map that shows the coordinates of defects based on the second mark coordinate RM2 (the position coordinate of the reference mark RM measured in the second defect inspection).

[0088] Generally, the second defect inspection, which uses short-wavelength inspection light, offers higher measurement accuracy. Therefore, in the case of defects detected by both the first and second defect inspections (matching defects), the second defect information obtained from the more accurate second defect inspection can be adopted as the third defect information.

[0089] Furthermore, for discrepancies in defects that are not detected in the second defect inspection, the first defect information can be used as the third defect information. Also, for discrepancies in defects that were detected in the second defect inspection, the second defect information can be used as the third defect information. And for matching defects, the second defect information can be used as the third defect information. This is because the second defect inspection, which generally uses short-wavelength inspection light, usually has higher measurement accuracy.

[0090] The third defect information includes information obtained by converting the defect dimensions in the first defect information and / or the second defect information. That is, the method for manufacturing a substrate with a multilayer reflective film includes the steps of: performing a first defect inspection on the substrate with a multilayer reflective film having a first coordinate accuracy and obtaining first defect information; performing a second defect inspection on the substrate with a multilayer reflective film having a second coordinate accuracy different from the first coordinate accuracy and obtaining second defect information; and obtaining third defect information by performing a size conversion on at least one of the defect dimensions from the defect dimensions in the first defect information and the defect dimensions in the second defect information.

[0091] Furthermore, the method for manufacturing a substrate with a multilayer reflective film includes the steps of: performing a first defect inspection having a first coordinate accuracy on the substrate with a multilayer reflective film and obtaining first defect information; performing a second defect inspection having a second coordinate accuracy different from the first coordinate accuracy on the substrate with a multilayer reflective film and obtaining second defect information; comparing the first defect information and the second defect information to identify matching defects, first mismatching defects detected only in the first defect inspection, and second mismatching defects detected only in the second defect inspection; and performing a size conversion on at least one of the matching defects, first mismatching defects, and second mismatching defects to obtain third defect information.

[0092] A first defect inspection having a first coordinate accuracy can be performed using a defect inspection device that uses the first wavelength described above. A second defect inspection having a second coordinate accuracy can be performed using a defect inspection device that uses the second wavelength described above.

[0093] The defect dimensions include the length (width), height, or depth in the X and Y directions, respectively, for the substrate 110 with the multilayer reflective film.

[0094] The size conversion may be performed on both the defect dimensions in the first defect information and the defect dimensions in the second defect information, or on only one of them. If the coordinate accuracy of the first defect information is lower than that of the second defect information, it is preferable to perform the size conversion on the defect dimensions in the first defect information. If the coordinate accuracy of the second defect information is higher than that of the first defect information, the size conversion may be performed only on the defect dimensions in the first defect information.

[0095] Furthermore, the size conversion may be performed on all of the matching defect dimensions, the first mismatched defect dimensions, and the second mismatched defect dimensions, or on only one of the matching defect dimensions, the first mismatched defect dimensions, and the second mismatched defect dimensions. If the first coordinate accuracy is lower than the second coordinate accuracy, it is preferable to perform the size conversion on the first mismatched defect dimension. Also, if the second coordinate accuracy is higher than the first coordinate accuracy, the size conversion may be performed only on the defect dimensions in the first defect information among the matching defect dimensions, the first mismatched defect dimensions, and the second mismatched defect dimensions.

[0096] Size conversion is performed by adding a predetermined size (buffer value) to the acquired defect dimensions. For example, α nm is added as a buffer value to the length in the X direction of the defect dimensions in the first defect information or the first mismatched defect, and α nm is added to the length in the Y direction. β nm is added as a buffer value to the length in the X direction of the defect dimensions in the second defect information, the second mismatched defect, or the matching defect, and β nm is added to the length in the Y direction. α is set according to the first coordinate precision, and β is set according to the second coordinate precision. If the first coordinate precision is lower than the second coordinate precision, it is preferable that α > β (where β is zero).

[0097] When adding buffer values ​​to the X-direction length and Y-direction length of the defect dimensions in the second mismatched defect and the matching defect, the buffer values ​​for the second mismatched defect dimension and the buffer values ​​for the matching defect dimension may be different. For example, β1 nm may be added as a buffer value to the X-direction length and Y-direction length of the second mismatched defect dimension, and β2 nm may be added as a buffer value to the X-direction length and Y-direction length of the matching defect dimension. If the first coordinate accuracy is lower than the second coordinate accuracy, it is preferable that β2 > β1 (where β1 includes zero).

[0098] By manufacturing a multilayer reflective substrate 110 having a third defect information, it is possible to obtain a multilayer reflective substrate 110 for manufacturing a reflective mask 200 that can more accurately correct drawing data based on defect inspection.

[0099] <<Third Defect Inspection>> The manufacturing method for the multilayer reflective substrate 110 of this embodiment may include a third defect inspection. The third defect inspection may include the following steps.

[0100] In the manufacturing method of the multilayer reflective film substrate 110 of this embodiment, it is preferable to further include a step for a third defect inspection in which, if there is a discrepancy defect between the first defect information and the second defect information, a first discrepancy defect that is detected only in the first defect inspection and a second discrepancy defect that is detected only in the second defect inspection are identified.

[0101] A first-order discrepancy defect is one that is detected only in the first defect inspection but not in the second defect inspection. A second-order discrepancy defect is one that is detected only in the second defect inspection but not in the first defect inspection. By identifying the first and second-order discrepancies, guidance can be obtained to determine which of the first and second defect information should be adopted.

[0102] In the manufacturing method of the multilayer reflective substrate 110 of this embodiment, it is preferable to further include a step of performing a third defect inspection on the multilayer reflective substrate 110 at a third wavelength different from the first and second wavelengths. Furthermore, it may further include a step of performing a third defect inspection on the multilayer reflective substrate 110 using a different apparatus or measurement method than the first and second defect inspections. In addition, it is preferable that the third defect inspection includes measuring the dimensions of at least one of the matching defects and the first mismatched defects. In addition, in the third defect inspection, the coordinates of the defect can be measured along with the defect dimensions. The defect dimensions include the length (width), height or depth in the X and Y directions, respectively, of the multilayer reflective substrate 110.

[0103] Preferably, the defect dimensions measured in the third defect inspection are added to the third defect information. Furthermore, if the coordinates of the defect are measured in the third defect inspection, these coordinates can also be added to the third defect information.

[0104] For the third defect inspection, a coordinate measuring instrument such as the "LMS-IPRO4" manufactured by KLA-Tencor, which performs coordinate measurement with a 365nm wavelength laser, or the "PROVE" coordinate measuring instrument manufactured by Carl Zeiss, which performs coordinate measurement with a 193nm wavelength laser, can be used. It is preferable to use the "PROVE" as the defect inspection instrument for the third defect inspection, as it provides a clearer observation image.

[0105] Furthermore, the third defect inspection may include a method for measuring the surface morphology of the defect. For example, an atomic force microscope (AFM), a scanning electron microscope (SEM), or an EUV light microscope can be used to obtain surface topography information of the defect. The third defect inspection may also include a partial inspection that measures a predetermined region (e.g., a 1 μm × 1 μm region) containing at least one of the matching defects and the first mismatched defects. Furthermore, the third defect inspection may include a partial inspection that, if there is a predetermined region containing at least one matching defect, a predetermined region containing at least one first mismatched defect, and a predetermined region containing at least one second mismatched defect, and the first coordinate accuracy is lower than the second coordinate accuracy, then measures the predetermined region containing at least one first mismatched defect and the predetermined region containing at least one matching defect, without measuring the predetermined region containing only the second mismatched defect. Furthermore, the third defect inspection may include a partial inspection in which, if there is a predetermined region containing at least one matching defect, a predetermined region containing at least one first mismatching defect, and a predetermined region containing at least one second mismatching defect, and the first coordinate accuracy is lower than the second coordinate accuracy, the predetermined region containing only matching defects or the second mismatching defect is not measured, but the predetermined region containing at least one first mismatching defect is measured.

[0106] By performing a third defect inspection, more accurate coordinates of the defect center can be obtained. Therefore, if there is a discrepancy between the coordinates of the defect center from the first and / or second defect inspection and the coordinates of the defect center from the third defect inspection, the defect coordinates from the third defect inspection can be used. This makes it possible to obtain a multilayer reflective substrate 110 for manufacturing a reflective mask 200 that can correct drawing data based on the defect inspection more accurately. Furthermore, by making the third defect inspection a partial inspection that measures only a predetermined area, the time required for the third defect inspection can be shortened, and a multilayer reflective substrate 110 for manufacturing a reflective mask 200 that can correct drawing data based on the defect inspection even more accurately can be obtained more efficiently. Making the third defect inspection, which is performed based on the first and second defect information, a partial inspection is particularly effective when the third defect inspection has high measurement accuracy but takes a long time to measure a predetermined area.

[0107] By further including a third defect inspection in the manufacturing method of the multilayer reflective substrate 110 of this embodiment, it is possible to obtain a multilayer reflective substrate 110 for manufacturing a reflective mask 200 that can perform correction of drawing data based on defect inspection with even greater accuracy.

[0108] <<Substrate 110 with multilayer reflective film containing defect information>> The configuration of the multilayer reflective film substrate 110 may include not only the physical configuration of the substrate 1 and the multilayer reflective film 5, but also defect information (third defect information) which is information regarding the location and dimensions of defects in the multilayer reflective film 5.

[0109] The multilayer reflective substrate 110 (and / or reflective mask blank 100) is typically delivered to the customer along with defect information as data. Therefore, the defect information can be considered part of the multilayer reflective substrate 110. For example, the defect information is delivered to the customer along with a storage medium linked to the multilayer reflective substrate 110 (and / or reflective mask blank 100), or to the substrate case in which the multilayer reflective substrate 110 (and / or reflective mask blank 100) is housed, or it is delivered to the customer via a server connected to a network such as the Internet. The defect information can be information regarding the location and dimensions of defects in the multilayer reflective film 5. Therefore, the manufacturing method of the multilayer reflective substrate 110 described above in this embodiment makes it possible to provide the customer with a third defect information obtained from the first and second defect information as defect information for the multilayer reflective film 5. By including defect information (third defect information) in the multilayer reflective substrate 110, it is possible to manufacture a reflective mask 200 that can more accurately correct drawing data based on defect inspection.

[0110] <Reflective Mask Blank 100> An embodiment of the reflective mask blank 100 of this embodiment will be described.

[0111] As shown in Figure 3, the reflective mask blank 100 of this embodiment has a multilayer reflective film substrate 110 manufactured as described above, and an absorber film 7 formed on the multilayer reflective film substrate 110. By using the reflective mask blank 100 of this embodiment, it is possible to manufacture a reflective mask 200 that can correct drawing data based on defect inspection more accurately.

[0112] <<Absorbing membrane 7>> The reflective mask blank 100 has an absorber film 7 on the substrate 110 with the multilayer reflective film described above. That is, the absorber film 7 is formed on the multilayer reflective film 5 (or on the protective film 6 if a protective film 6 is formed). The basic function of the absorber film 7 is to absorb EUV light. The absorber film 7 may be an absorber film 7 intended for absorbing EUV light, or it may be an absorber film 7 having a phase shift function that also takes into account the phase difference of EUV light. An absorber film 7 having a phase shift function absorbs EUV light and reflects a portion of it to shift the phase. That is, in a reflective mask 200 patterned with an absorber film 7 having a phase shift function, in the area where the absorber film 7 is formed, it absorbs EUV light to reduce its brightness while reflecting some of the light at a level that does not adversely affect pattern transfer. Also, in the area where the absorber film 7 is not formed (field area), EUV light is reflected from the multilayer reflective film 5 via the protective film 6. Therefore, a desired phase difference is achieved between the light reflected from the absorber film 7, which has a phase-shift function, and the light reflected from the field section. The absorber film 7, which has a phase-shift function, is formed such that the phase difference between the light reflected from the absorber film 7 and the light reflected from the multilayer reflective film 5 is between 170 and 190 degrees. The light with inverted phase differences near 180 degrees interferes with each other at the pattern edge, improving the image contrast of the projected optical image. This improvement in image contrast increases the resolution, and various exposure-related margins such as exposure margin and focus margin can be increased.

[0113] The absorber film 7 can be a single layer film. Alternatively, the absorber film 7 can be a multilayer film consisting of multiple layers. When the absorber film 7 is a single layer film, it has the advantage of reducing the number of steps in mask blank manufacturing and increasing production efficiency. In the case of a multilayer film, the optical constants and film thickness of the upper absorber film can be appropriately set so that it acts as an anti-reflective film during mask pattern inspection using light. This improves the inspection sensitivity during mask pattern inspection using light. Furthermore, if a film with oxygen (O) and nitrogen (N), etc., which improve oxidation resistance is added to the upper absorber film, the stability over time is improved. In this way, various functions can be added by making the absorber film 7 a multilayer film. When the absorber film 7 has a phase shift function, the range of adjustment on the optical surface can be greatly increased by making it a multilayer film, making it easier to obtain the desired reflectance.

[0114] The material for the absorber film 7 is not particularly limited, as long as it has the function of absorbing EUV light and can be processed by etching or the like (preferably etchable by dry etching with chlorine (Cl) or fluorine (F) gases). As materials possessing such functions, at least one metal selected from palladium (Pd), silver (Ag), platinum (Pt), gold (Au), iridium (Ir), tungsten (W), chromium (Cr), cobalt (Co), manganese (Mn), tin (Sn), tantalum (Ta), vanadium (V), nickel (Ni), hafnium (Hf), iron (Fe), copper (Cu), tellurium (Te), zinc (Zn), magnesium (Mg), germanium (Ge), aluminum (Al), rhodium (Rh), ruthenium (Ru), molybdenum (Mo), niobium (Nb), titanium (Ti), zirconium (Zr), yttrium (Y), and silicon (Si), or compounds thereof, can be preferably used.

[0115] The absorber film 7 can be formed by magnetron sputtering methods such as DC sputtering and RF sputtering. For example, the absorber film 7 can be deposited by reactive sputtering using an argon gas doped with oxygen or nitrogen, with a target containing tantalum and boron.

[0116] The concave reference mark 20 (reference mark RM) formed on the multilayer reflective substrate 110 can be transferred to the absorber film 7 and the resist film 8. When an etching mask film is formed between the absorber film 7 and the resist film 8, the concave reference mark 20 formed on the multilayer reflective substrate 110 can be transferred to the absorber film 7, the etching mask film, and the resist film 8. The same applies when a reference mark 22 (reference mark CM) is formed on the multilayer reflective substrate 110.

[0117] In this embodiment, the absorbent membrane 7 of the reflective mask blank 100 preferably includes a second reference mark FM formed on the absorbent membrane 7 and a transferred reference mark RM' on which the reference mark RM has been transferred to the absorbent membrane 7.

[0118] The second reference mark FM is not formed on the multilayer reflective film substrate 110, but can be formed on the absorber film 7 of the reflective mask blank 100. Figure 7 shows a plan view of the reflective mask blank 100 on which the roughly cross-shaped reference mark 24, which is the second reference mark FM, is formed. Figure 7 shows how the reference mark 20 (reference mark RM) formed on the multilayer reflective film 5 of the multilayer reflective film substrate 110, as shown in Figure 5, has been transferred to the absorber film 7 as reference mark 20a (transfer reference mark RM').

[0119] The second reference mark FM can be formed on the multilayer reflective substrate 110 as a reference mark CM. That is, the multilayer reflective substrate 110 shown in Figure 6 has reference marks 20 (reference mark RM) and 22 (reference mark CM) formed on it. When an absorber film 7 is formed on the multilayer reflective substrate 110 shown in Figure 6, these reference marks 20 and 22 are transferred to the absorber film 7. As a result, in the reflective mask blank 100 shown in Figure 7, they become reference mark 20a (transferred reference mark RM') and reference mark 24. Reference mark 24 can be used as the second reference mark FM.

[0120] Reference mark 24 (second reference mark FM) can be used, for example, as an FM (fiducial mark). An FM is a mark used as a reference for defect coordinates when drawing a pattern with an electron beam lithography system. An FM is usually a cross shape, as shown as reference numeral 24 in Figure 7.

[0121] Figure 8 shows a schematic diagram of the shape of the reference mark 24 (second reference mark FM) that can be used as an FM (fiducial mark). The widths W1 and W2 of the reference mark 24, which has a roughly cross shape, are, for example, 200 nm to 10 μm. The length L of the reference mark 24 is, for example, 100 μm to 1500 μm. Figure 8 shows an example of a reference mark 24 with a roughly cross shape, but the shape of the reference mark 24 is not limited to this. The shape of the reference mark 24 may be, for example, roughly L-shaped, circular, triangular, or square in plan view.

[0122] By using the reference mark 24 (second reference mark FM) as the FM, defect coordinates can be controlled with high precision. When a pattern is drawn on the resist film 8 by the electron beam lithography apparatus, the reference mark 24 transferred to the resist film 8 is used as the FM, which is the reference for the defect location. For example, by detecting the FM with the coordinate measuring instrument of the electron beam lithography apparatus, the defect coordinates acquired by the defect inspection apparatus can be converted to the coordinate system of the electron beam lithography apparatus. This allows for correction of the drawing data of the pattern drawn by the electron beam lithography apparatus so that, for example, the defect is placed below the absorber pattern 7a (DM technique). By correcting the drawing data, the impact of defects on the final manufactured reflective mask 200 can be reduced.

[0123] The absorbent membrane 7 may include a second reference mark FM formed on the absorbent membrane 7, a transferred reference mark RM' formed by transferring the reference mark RM to the absorbent membrane 7, and / or a transferred reference mark CM' formed by transferring the reference mark CM to the absorbent membrane 7.

[0124] The reference mark 22 (reference mark CM) shown in Figure 6 can be used as an AM (alignment mark). If the reference mark RM is difficult to transfer to the absorber membrane 7, or if the transferred reference mark RM' transferred to the absorber membrane 7 is difficult to detect with an electron beam, the transferred reference mark CM', which is the reference mark CM transferred to the absorber membrane 7, can be used.

[0125] When the reference mark 22 (reference mark CM) is used as the AM, for example, the widths W1 and W2 of the reference mark 22, which has a roughly cross shape, are, for example, 200 nm to 10 μm. The length L of the reference mark 22 is, for example, 100 μm to 1500 μm. The shape of the reference mark 22 is not limited to a roughly cross shape, but may be, for example, roughly L-shaped, circular, triangular, or square in plan view.

[0126] When AM (reference mark 20, or reference mark 20 and reference mark 22) is formed on the multilayer reflective substrate 110, FM (second reference mark FM, which is reference mark 24) is formed on the absorber film 7 on the multilayer reflective substrate 110. The AM is transferred to the absorber film 7. The AM is detectable by a defect inspection device and a coordinate measuring instrument. The FM is detectable by a coordinate measuring instrument and an electron beam lithography device. Since both AM and FM can be detected by a coordinate measuring instrument, their relative positional relationship can be controlled with high precision. Therefore, defect coordinates based on AM acquired by the defect inspection device can be converted with high precision to defect coordinates based on FM used in the electron beam lithography device. The number of AMs can be greater than the number of FMs. Furthermore, the detection accuracy of AM can be increased by partially removing the absorber film 7 on the AM.

[0127] In the manufacturing method of the reflective mask blank 100 of this embodiment, it is preferable to perform a defect inspection on the reflective mask blank 100 using the same procedure as the third defect inspection performed on the multilayer reflective film substrate 110 described above.

[0128] In the manufacturing method of the reflective mask blank 100 of this embodiment, if there is a discrepancy between the first defect information and the second defect information for the multilayer reflective film substrate 110 described above, before performing the third defect inspection, it is preferable to further include a step of identifying a first discrepancy defect that is detected only in the first defect inspection and a second discrepancy defect that is detected only in the second defect inspection.

[0129] A first discrepancy defect is a defect that is detected only in the first defect inspection of the manufacturing method of the multilayer reflective substrate 110, but not in the second defect inspection. A second discrepancy defect is a defect that is detected only in the second defect inspection of the manufacturing method of the multilayer reflective substrate 110, but not in the first defect inspection. By identifying the first and second discrepancies, it is possible to obtain guidance for deciding which of the first and second defect information should be adopted.

[0130] In the manufacturing method of the reflective mask blank 100 of this embodiment, it is preferable to further include a step of performing a third defect inspection on the reflective mask blank 100 at a third wavelength different from the first and second wavelengths. Furthermore, it may further include a step of performing a third defect inspection on the reflective mask blank 100 using a different apparatus or measurement method than the first and second defect inspections. Furthermore, it is preferable that the third defect inspection includes measuring the dimensions of at least one of the matching defects and the first mismatched defects transferred to the absorber film 7. In addition, in the third defect inspection, the coordinates of the defect can be measured along with the defect dimensions. The defect dimensions include the length (width), height or depth in the X and Y directions, respectively, with respect to the multilayer reflective film substrate 110.

[0131] Furthermore, it is preferable that the defect dimensions measured in the third defect inspection are added to the third defect information. Also, if the coordinates of the defect are measured in the third defect inspection, the coordinates of the defect can also be added to the third defect information.

[0132] For the third defect inspection of the reflective mask blank 100, a defect inspection device can be used, for example, the "LMS-IPRO4" coordinate measuring instrument manufactured by KLA-Tencor, which performs coordinate measurement with a 365 nm wavelength laser, or the "PROVE" coordinate measuring instrument manufactured by Carl Zeiss, which performs coordinate measurement with a 193 nm wavelength laser. It is preferable to use the "PROVE" as the defect inspection device for the third defect inspection in order to obtain a clear observation image. Furthermore, the third defect inspection may include a method for measuring the surface morphology of the defect. For example, an atomic force microscope (AFM), scanning electron microscope (SEM), or EUV light microscope can be used to obtain surface topography information of the defect. The third defect inspection may also include a partial inspection that measures a predetermined area (e.g., a 1 μm × 1 μm area) containing at least one of the matching defect and the first mismatched defect.

[0133] By further including a third defect inspection in the manufacturing method of the reflective mask blank 100 of this embodiment, it is possible to obtain a reflective mask blank 100 for manufacturing a reflective mask 200 that can perform correction of drawing data based on defect inspection with even greater accuracy.

[0134] <<Back surface conductive film 2>> A back surface conductive film 2 for electrostatic chucks is formed on the second main surface (back surface) of the substrate 1 (opposite the surface on which the multilayer reflective film 5 is formed, and on the intermediate layer if an intermediate layer such as a hydrogen penetration suppression film is formed on the substrate 1). The sheet resistance required for the back surface conductive film 2 for electrostatic chucks is usually 100 Ω / □ or less. The method for forming the back surface conductive film 2 is, for example, a magnetron sputtering method or an ion beam sputtering method using a target of a metal such as chromium or tantalum, or an alloy thereof. If the back surface conductive film 2 is made of a material containing chromium (Cr), it is preferable that it be a Cr compound containing at least one selected from boron, nitrogen, oxygen, and carbon in addition to Cr. Examples of Cr compounds include CrN, CrON, CrCN, CrCON, CrBN, CrBON, CrBCN, and CrBOCN. As the material containing tantalum (Ta) for the back surface conductive film 2, it is preferable to use Ta (tantalum), an alloy containing Ta, or a Ta compound containing at least one of boron, nitrogen, oxygen, and carbon in addition to any of these. Examples of Ta compounds include TaB, TaN, TaO, TaON, TaCON, TaBN, TaBO, TaBON, TaBCON, TaHf, TaHfO, TaHfN, TaHfON, TaHfCON, TaSi, TaSiO, TaSiN, TaSiON, and TaSiCON. The thickness of the back surface conductive film 2 is not particularly limited as long as it satisfies the function for electrostatic chucks, but is usually between 10 nm and 200 nm. Furthermore, this back surface conductive film 2 also serves to adjust the stress on the second main surface side of the mask blank 100. That is, the back surface conductive film 2 is adjusted to balance the stress from the various films formed on the first main surface side so that a flat reflective mask blank 100 can be obtained.

[0135] Furthermore, the back surface conductive film 2 can be formed on the multilayer reflective substrate 110 before forming the absorber film 7 described above. In that case, a multilayer reflective substrate 110 with a back surface conductive film 2 as shown in Figure 2 can be obtained.

[0136] <<Etching Mask Film>> The reflective mask blank 100 manufactured by the manufacturing method of this embodiment may have an etching mask film (also called an "etching hard mask film") on top of the absorber film 7. Typical materials for the etching mask film include silicon (Si), and materials to which at least one element selected from oxygen (O), nitrogen (N), carbon (C), and hydrogen (H) has been added to silicon, or chromium (Cr), and materials to which at least one element selected from oxygen (O), nitrogen (N), carbon (C), and hydrogen (H) has been added to chromium. Specifically, examples include SiO2, SiON, SiN, SiO, Si, SiC, SiCO, SiCN, SiCON, Cr, CrN, CrO, CrON, CrC, CrCO, CrCN, and CrOCN. However, if the absorber film 7 is a compound containing oxygen, materials containing oxygen (e.g., SiO2) should be avoided as the etching mask film from the viewpoint of etching resistance. If the reflective mask blank 100 has an etching mask film, it becomes possible to reduce the thickness of the resist film 8 when manufacturing the reflective mask 200, which is advantageous for miniaturizing the pattern.

[0137] <<Other Thin Films>> The reflective mask blank 100 manufactured by the manufacturing method of this embodiment may have a resist film 8 on top of the absorber film 7 or the etching mask film described above. That is, a reflective mask blank 100 including a resist film 8 is included in the reflective mask blank 100 of this embodiment.

[0138] <Reflective Mask 200> The manufacturing method of the reflective mask 200 of this embodiment includes patterning the absorber film 7 of the reflective mask blank 100 described above to form an absorber pattern 7a on the multilayer reflective film 5. That is, the reflective mask 200 of this embodiment has an absorber pattern 7a on the multilayer reflective film 5. By using the reflective mask blank 100 of this embodiment, a reflective mask 200 can be obtained that can correct drawing data based on defect inspection more accurately.

[0139] A reflective mask 200 can be manufactured using the reflective mask blank 100 of this embodiment. Only an overview is provided here; a detailed explanation will follow later in the examples section with reference to the drawings.

[0140] A reflective mask blank 100 is prepared, and a resist film 8 is formed on the outermost surface of its first main surface (on top of the absorber film 7, as described in the following examples) (this step is unnecessary if the reflective mask blank 100 already has a resist film 8). A desired pattern, such as a circuit pattern, is drawn (exposed) onto this resist film 8, and then developed and rinsed to form a predetermined resist pattern 8a.

[0141] The absorber pattern 7a is formed by dry etching the absorber film 7 using this resist pattern 8a as a mask. As the etching gas, a gas selected from chlorine-based gases such as Cl2, SiCl4, and CHCl3, a mixed gas containing chlorine-based gas and O2 in a predetermined ratio, a mixed gas containing chlorine-based gas and He in a predetermined ratio, a mixed gas containing chlorine-based gas and Ar in a predetermined ratio, fluorine-based gases such as CF4, CHF3, C2F6, C3F6, C4F6, C4F8, CH2F2, CH3F, C3F8, SF6, and F2, and a mixed gas containing fluorine-based gas and O2 in a predetermined ratio can be used. If oxygen is present in the etching gas at the final stage of etching, surface roughness will occur on the Ru-based protective film 6. For this reason, it is preferable to use an etching gas that does not contain oxygen in the over-etching stage when the Ru-based protective film 6 is exposed to etching.

[0142] Subsequently, the resist pattern 8a is removed using ashing or a resist stripping solution to create an absorber pattern 7a with the desired circuit pattern.

[0143] By following the above steps, the reflective mask 200 of this embodiment can be obtained.

[0144] The manufacturing method for the reflective mask 200 of this embodiment makes it possible to manufacture a reflective mask 200 that can more accurately correct drawing data based on defect inspection. In other words, according to this embodiment, defect reduction technology (DM technology) can be applied more appropriately when manufacturing the reflective mask 200.

[0145] <Manufacturing method for semiconductor devices> The semiconductor device manufacturing method of this embodiment includes a step of forming a transfer pattern on a transfer object by performing a lithography process using an exposure apparatus with the reflective mask 200 described above.

[0146] In this embodiment, the correction of drawing data based on defect inspection can be performed more accurately during the manufacturing of the reflective mask 200. In other words, according to this embodiment, the defect reduction technology (DM technology) can be applied more appropriately during the manufacturing of the reflective mask 200. As a result, the throughput during the manufacturing of semiconductor devices can be improved. Furthermore, since semiconductor devices can be manufactured using a reflective mask 200 that does not have defects that affect transfer onto the multilayer reflective film 5, the yield reduction of semiconductor devices caused by defects in the multilayer reflective film 5 can be suppressed.

[0147] By performing EUV exposure using the reflective mask 200 of this embodiment, a desired transfer pattern can be formed on a semiconductor substrate. In addition to this lithography process, various other processes such as etching the workpiece, forming insulating films and conductive films, introducing dopants, and annealing can be performed to manufacture semiconductor devices with a high yield in which the desired electronic circuits are formed. [Examples]

[0148] The embodiments of the present invention will be described in detail below with reference to the drawings. Note that the following embodiments are examples of how the present invention can be implemented, and do not limit the present invention to their scope.

[0149] <Example 1> As shown in Figure 1, the multilayer reflective film substrate 110 of Example 1 has a substrate 1 and a multilayer reflective film 5.

[0150] A SiO2-TiO2 glass substrate, a low thermal expansion glass substrate of size 6025 (approximately 152 mm × 152 mm × 6.35 mm), with both the first and second main surfaces polished, was prepared and designated as substrate 1. Polishing was performed using a rough polishing process, a precision polishing process, a local polishing process, and a touch polishing process to obtain a flat and smooth main surface.

[0151] A multilayer reflective film 5 was formed on the main surface of the substrate 1 opposite to the side where the conductive film 2 on the back surface is formed, by periodically stacking Mo films / Si films.

[0152] Specifically, using a Mo target and a Si target, Mo and Si films were alternately layered on substrate 1 by ion beam sputtering (using Ar). The thickness of the Mo film was 2.8 nm. The thickness of the Si film was 4.2 nm. The thickness of one period of Mo / Si film was 7.0 nm. Such Mo / Si films were layered for 40 periods, and finally, a Si film with a thickness of 4.0 nm was deposited to form a multilayer reflective film 5.

[0153] A protective film 6 containing a Ru compound was formed on the multilayer reflective film 5. Specifically, using a RuNb target (Ru: 80 atomic%, Nb: 20 atomic%), a protective film 6 made of RuNb was formed on the multilayer reflective film 5 by DC magnetron sputtering in an Ar gas atmosphere. The thickness of the protective film 6 was 2.5 nm.

[0154] Next, a reference mark RM (reference mark 20) ​​was formed on the protective film 6 by laser processing that reached the multilayer reflective film 5. The laser processing conditions were as follows: Laser type: Semiconductor laser with a wavelength of 405 nm Laser output: 7mW (continuous wave) Spot size: 430nmφ

[0155] The shape and dimensions of standard mark 20 were as follows: Shape: Circular (dot mark) Depth D: 40nm Diameter: 1.5μm

[0156] As shown in Figure 5, eight reference marks RM (reference marks 20) were formed. The locations where the reference marks 20 were formed were as shown in Figure 5, outside the effective area of ​​132 mm × 132 mm (the area inside the dashed line A).

[0157] Next, a first defect inspection was performed on the multilayer reflective substrate 110 using the "MAGICS M8650" EUV exposure mask / substrate / blank defect inspection system manufactured by Lasertec, Inc., which has an inspection light source wavelength of 355 nm. The first defect information was obtained, consisting of the first defect coordinates and the dimensions corresponding to the defect. The first defect coordinates were measured relative to the reference mark RM. Therefore, the first defect coordinates include the first mark coordinate RM1 of the reference mark RM. In this way, a first defect map was obtained as the first defect information. Table 1 shows the number of defects in the first defect inspection of Example 1.

[0158] Next, a second defect inspection was performed on the multilayer reflective film substrate 110 using an ABI (Actinic Blank Inspection) apparatus whose inspection light source wavelength is the same as the exposure light source wavelength of 13.5 nm. The second defect information obtained included the second defect coordinates and the dimensions corresponding to the defects. The second defect coordinates were measured relative to the reference mark RM. Therefore, the second defect coordinates include the second mark coordinate RM2 of the reference mark RM. In this way, a second defect map was obtained as second defect information. Table 1 shows the number of defects in the second defect inspection of Example 1.

[0159] Next, based on the relative position coordinates of the first mark coordinate RM1 and the second mark coordinate RM2, the first defect coordinate, relative to the first mark coordinate RM1, was converted to a coordinate relative to the second mark coordinate RM2.

[0160] Next, the coordinate-transformed first defect information was compared with the second defect information to determine the presence or absence of mismatched and matching defects. Table 1 shows the number of mismatched and matching defects. For mismatched defects, the number of mismatched defects detected only in the first defect inspection (first inspection) and the number of mismatched defects detected only in the second defect inspection (second inspection) are listed.

[0161] Next, if there was a matching defect between the first and second defect information, the matching defect was adopted as the third defect information, specifically the defect in the second defect map based on the second mark coordinate RM2. Furthermore, for mismatched defects that were not detected in the second defect inspection, the coordinate-transformed version of the first defect information (the defect in the first defect map) was used as the third defect information. Also, for mismatched defects that were detected in the second defect inspection, the second defect information (the defect in the second defect map) was used as the third defect information.

[0162] As described above, a substrate 110 with a multilayer reflective film according to Example 1 was manufactured, having a third defect information based on the first and second defect information.

[0163] Next, a reflective mask blank 100 was manufactured by forming an absorber film 7 on the protective film 6 of the multilayer reflective substrate 110 of Example 1. Specifically, the absorber film 7, consisting of a laminated film of TaBN (thickness 56 nm) and TaBO (thickness 14 nm), was formed by DC magnetron sputtering. The TaBN film was formed using a TaB target by reactive sputtering in a mixed gas atmosphere of Ar gas and N2 gas. The TaBO film was formed using a TaB target by reactive sputtering in a mixed gas atmosphere of Ar gas and O2 gas. In this way, the reflective mask blank 100 of Example 1 was manufactured.

[0164] Next, a second reference mark FM was formed on the surface of the reflective mask blank 100 of Example 1. Figure 7 shows the state in which a reference mark 24 was formed as the second reference mark FM. In the example in Figure 7, eight second reference marks FM (reference marks 24) were formed. The locations where the reference marks 24 were formed were as shown in Figure 7, outside the effective area of ​​132 mm × 132 mm (the area inside the dashed line A).

[0165] The second reference mark FM (reference mark 24) was formed on the absorber film 7 by laser processing. The laser processing conditions were as follows: Laser type: Semiconductor laser with a wavelength of 405 nm Laser output: 20mW (continuous wave) Spot size: 430nmφ

[0166] The shape and dimensions of the second standard mark FM (standard mark 24) (see Figure 8) were as follows: Shape: Approximately cross-shaped Depth D: 70nm Width W1 and W2: 5 μm Length L: 1mm

[0167] Subsequently, using the KLA-Tencor "LMS-IPRO4" coordinate measuring instrument, which performs coordinate measurements with a 365nm wavelength laser, the eight transfer reference marks RM' and the eight second reference marks FM (reference marks 24) transferred to the absorber film 7 were measured. Based on the relative position coordinates of the transfer reference marks RM' and the second reference marks FM, the third defect information described above was coordinate-transformed using the second reference marks FM as the reference, and a defect map with defect coordinates was obtained.

[0168] A reflective mask 200 was manufactured using the reflective mask blank 100 of Example 1, which was manufactured as described above. Figure 4 shows a schematic cross-sectional diagram illustrating the manufacturing method of the reflective mask.

[0169] First, a resist film 8 was formed on the absorber film 7 of the reflective mask blank 100 of Example 1 (see Figure 4(a)) (see Figure 4(b)).

[0170] Next, a pattern was drawn on the resist film 8 using an electron beam lithography system. When drawing the pattern, a defect map was used that used the second reference mark FM (reference mark 24) as the reference for defect coordinates, ensuring that no defects existed in the exposed region of the multilayer reflective film 5 of the absorber pattern 7a (DM technique). After drawing the pattern, a predetermined development process was performed to form the resist pattern 8a on the absorber film 7 (see Figure 4(c)).

[0171] Using the resist pattern 8a as a mask, an absorber pattern 7a was formed on the absorber film 7 (see Figure 4(d)). Specifically, the upper TaBO film was dry-etched with a fluorine-based gas (CF4 gas), and then the lower TaBN film was dry-etched with a chlorine-based gas (Cl2 gas).

[0172] The resist pattern 8a remaining on the absorber pattern 7a was removed with hot sulfuric acid to obtain the reflective mask 200 of Example 1 (see Figure 4(e)).

[0173] The EUV reflective mask 200 of Example 1 was inspected using a mask defect inspection device (Teron 600 series, manufactured by KLA-Tencor). As shown in Table 1, no defects were found in the exposed area of ​​the multilayer reflective film 5 of the absorber pattern 7a during this defect inspection.

[0174] <Example 2> In Example 2, the multilayer reflective substrate 110 and the reflective mask blank 100 were manufactured in the same manner as in Example 1, except that a third defect inspection was performed at a third wavelength different from the first and second wavelengths.

[0175] In other words, when manufacturing the multilayer reflective substrate 110 of Example 2, a multilayer reflective substrate 110 having a third defect information based on the first and second defect information was manufactured, similar to Example 1. Next, the multilayer reflective substrate 110 of Example 2 was manufactured by performing a third defect inspection on this multilayer reflective substrate 110. Table 1 shows the number of defects in the first to third defect inspections of Example 2.

[0176] The third defect inspection of the multilayer reflective film substrate 110 in Example 2 was performed using a Carl Zeiss PROVE coordinate measuring instrument that performs coordinate measurement with a 193 nm wavelength laser. The third defect inspection measured the coordinates and dimensions of matching defects and the first mismatched defects (defects detected only in the first defect inspection and not in the second defect inspection). In the third defect inspection, the reference mark RM (reference mark 20) ​​was used as the reference mark for the coordinates.

[0177] Based on the defect information obtained from the third defect inspection, the defect dimensions of the matching defects in the third defect information were changed to the defect dimensions obtained from the third defect inspection. In addition, the defect dimensions and coordinates of the first mismatched defects in the third defect information were changed to the defect dimensions and coordinates obtained from the third defect inspection. This is because the measurements obtained from the third defect inspection are more reliable than the measurements obtained from the first and second defect inspections.

[0178] As described above, a substrate 110 with a multilayer reflective film of Example 2 was manufactured having the first defect information, the second defect information, and the third defect information based on the measurement values ​​of the third defect inspection.

[0179] Next, a reflective mask blank 100 of Example 2 was manufactured in the same manner as in Example 1. Using the reflective mask blank 100 of Example 2, a reflective mask 200 of Example 2 was manufactured in the same manner as in Example 1.

[0180] The EUV reflective mask 200 of Example 2 was inspected using a mask defect inspection device (Teron 600 series, manufactured by KLA-Tencor). As shown in Table 1, no defects were found in the exposed area of ​​the multilayer reflective film 5 of the absorber pattern 7a during this defect inspection.

[0181] <Example 3> The multilayer reflective film substrate 110 of Example 3 was manufactured in the same manner as in Example 1. Next, the reflective mask blank 100 of Example 3 was manufactured in the same manner as in Example 1, except that a third defect inspection was performed at a third wavelength different from the first and second wavelengths.

[0182] Specifically, when manufacturing the multilayer reflective substrate 110 of Example 3, a multilayer reflective substrate 110 having a third defect information based on the first and second defect information was manufactured, similar to Example 1. Table 1 shows the number of defects in the first and second defect inspections of Example 3.

[0183] Next, when manufacturing the reflective mask blank 100 of Example 3, a reflective mask blank 100 having an absorbent membrane 7 was manufactured in the same manner as in Example 1. Then, a third defect inspection was performed on the reflective mask blank 100 of Example 3. Table 1 shows the number of defects found in the third defect inspection of Example 3.

[0184] The third defect inspection of the reflective mask blank 100 in Example 3 was performed using the Carl Zeiss PROVE coordinate measuring instrument, which uses a 193 nm wavelength laser for coordinate measurement. The third defect inspection measured the coordinates and dimensions of matching defects and the first mismatched defects (defects detected only in the first defect inspection and not in the second defect inspection). In the third defect inspection, the reference mark used as the coordinate reference was the transfer reference mark RM' (reference mark 20a).

[0185] Based on the defect information obtained from the third defect inspection, the defect dimensions of the matching defects in the third defect information were changed to the defect dimensions obtained from the third defect inspection. In addition, the defect dimensions and coordinates of the first mismatched defects in the third defect information were changed to the defect dimensions and coordinates obtained from the third defect inspection. This is because the measurements obtained from the third defect inspection are more reliable than the measurements obtained from the first and second defect inspections.

[0186] In this manner, a reflective mask blank 100 of Example 3 was manufactured, having the first defect information, the second defect information, and the third defect information based on the measurement values ​​of the third defect inspection.

[0187] Next, using the reflective mask blank 100 of Example 3, the reflective mask 200 of Example 3 was manufactured in the same manner as in Example 1.

[0188] The EUV reflective mask 200 of Example 3 was inspected using a mask defect inspection device (Teron 600 series, manufactured by KLA-Tencor). As shown in Table 1, no defects were found in the exposed area of ​​the multilayer reflective film 5 of the absorber pattern 7a during this defect inspection.

[0189] <Example 4> In Example 4, the multilayer reflective substrate 110 and the reflective mask blank 100 were manufactured in the same manner as in Example 1, except that a third defect inspection, different from the first and second defect inspections, was performed.

[0190] In other words, when manufacturing the multilayer reflective substrate 110 of Example 4, a multilayer reflective substrate 110 having a third defect information based on the first defect information and the second defect information was manufactured, similar to Example 1. Next, the multilayer reflective substrate 110 of Example 4 was manufactured by performing a third defect inspection on this multilayer reflective substrate 110. As a result, two first-order discrepancies were detected by the first defect inspection alone, four second-order discrepancies were detected by the second defect inspection alone, and five matching defects were found.

[0191] The third defect inspection of the multilayer reflective film substrate 110 in Example 4 was performed using an atomic force microscope (AFM) manufactured by Park Systems. The third defect inspection measured the coordinates and surface morphology of the first discrepancy defect (a defect detected only in the first defect inspection but not in the second defect inspection). Since the coordinates of the defect center obtained in the first defect inspection and the coordinates of the defect center obtained in the third defect inspection were different, the coordinates of the first discrepancy defect were those obtained in the third defect inspection. In the third defect inspection, the reference mark RM (reference mark 20) ​​was used as the reference mark for the coordinates.

[0192] In this manner, a substrate 110 with a multilayer reflective film of Example 4 was manufactured, having the first defect information, the second defect information, and the third defect information based on the measurement values ​​of the third defect inspection.

[0193] Next, a reflective mask blank 100 of Example 4 was manufactured in the same manner as in Example 1. Using the reflective mask blank 100 of Example 4, a reflective mask 200 of Example 4 was manufactured in the same manner as in Example 1.

[0194] The EUV reflective mask 200 of Example 4 was inspected using a mask defect inspection device (Teron 600 series, manufactured by KLA-Tencor). No defects were found in the exposed area of ​​the multilayer reflective film 5 of the absorber pattern 7a during this defect inspection.

[0195] <Comparative Example 1> In the manufacturing of the multilayer reflective substrate 110 of Comparative Example 1, the multilayer reflective substrate 110 was manufactured in the same manner as in Example 1, except that the first defect inspection was not performed. Therefore, the multilayer reflective substrate 110 of Comparative Example 1 is a multilayer reflective substrate 110 that has only defect information corresponding to the second defect information of the second defect inspection of Example 1. Table 1 shows the number of defects in the second defect inspection of Comparative Example 1.

[0196] In the production of the reflective mask blank 100 of Comparative Example 1, the reflective mask blank 100 was manufactured in the same manner as in Example 1.

[0197] At that time, using the KLA-Tencor "LMS-IPRO4" coordinate measuring instrument, which performs coordinate measurements with a 365nm wavelength laser, the eight transfer reference marks RM' and the eight second reference marks FM (reference marks 24) transferred to the absorber film 7 were measured. Based on the relative position coordinates of the transfer reference marks RM' and the second reference marks FM, the second defect information described above was coordinate-transformed using the second reference marks FM as the reference, and a defect map with defect coordinates was obtained.

[0198] In the manufacturing of the reflective mask 200 of Comparative Example 1, a resist film 8 was formed on the absorber film 7 of the reflective mask blank 100.

[0199] Next, a pattern was drawn on the resist film 8 using an electron beam lithography system. When drawing the pattern, a defect map was used that used the second reference mark FM (reference mark 24) as the reference for defect coordinates, so that defects were not present in the exposed areas of the multilayer reflective film 5 of the absorber pattern 7a. After drawing the pattern, a predetermined development process was performed to form the resist pattern 8a on the absorber film 7.

[0200] Next, an absorber pattern 7a was formed in the same manner as in Example 1 to obtain the reflective mask 200 of Comparative Example 1.

[0201] The EUV reflective mask 200 of Comparative Example 1 was inspected using a mask defect inspection device (Teron 600 series, manufactured by KLA-Tencor). As shown in Table 1, this defect inspection detected two defects in the exposed area of ​​the multilayer reflective film 5 of the absorber pattern 7a.

[0202] From the above, it has become clear that by using the multilayer reflective film substrate 110 and reflective mask blank 100 of Examples 1 to 3 of this embodiment, it is possible to manufacture a reflective mask 200 that can more accurately correct drawing data based on defect inspection. Therefore, it is clear that by using the multilayer reflective film substrate 110 and reflective mask blank 100 of this embodiment, the technique of correcting drawing data based on defect data and device pattern data so that an absorber pattern 7a is formed at the location where a defect exists, thereby reducing defects (DM technique), can be appropriately applied.

[0203] [Table 1] [Explanation of symbols]

[0204] 1 circuit board 2. Conductive film on the back surface 5 Multilayer reflective film 6 Protective film 7 Absorbent membrane 7a Absorber pattern 8. Resist film 8a Resist Pattern 20 Standard Mark (Standard Mark RM) 20a Standard mark (Transfer standard mark RM') 22. Standard Mark (Standard Mark CM) 24. Standard Mark (Second Standard Mark FM) 100 Reflective Mask Blanks 110 Multilayer reflective substrate 200 Reflective Masks

Claims

1. A method for manufacturing a substrate with a multilayer reflective film, which includes a substrate and a multilayer reflective film on the substrate that reflects EUV light, A step of performing a first defect inspection on the substrate with the multilayer reflective film using a first wavelength and obtaining first defect information, A step of performing a second defect inspection on the substrate with the multilayer reflective film using a second wavelength different from the first wavelength, and obtaining second defect information, The process includes a step of obtaining third defect information by comparing the first defect information and the second defect information to determine the presence or absence of mismatched defects and matching defects, The aforementioned multilayer reflective substrate includes a reference mark RM, The first defect information includes the first mark coordinate RM1 of the reference mark RM and the first defect coordinate, The second defect information includes the second mark coordinate RM2 of the reference mark RM and the second defect coordinate, The third step of acquiring defect information involves converting the first defect coordinates, based on the relative position coordinates of the first mark coordinate RM1 and the second mark coordinate RM2, to coordinates based on the second mark coordinate RM2. A method for manufacturing a substrate with a multilayer reflective film, characterized in that the determination of whether or not there are mismatched defects and matching defects includes comparing a defect distance calculated based on the distance between the transformed first defect coordinates and the second defect coordinates with a defect length calculated based on the dimensions of the first defect and the dimensions of the second defect, and determining that it is a matching defect if the defect distance is shorter than the defect length.

2. The second wavelength mentioned above is a wavelength similar to the exposure wavelength. The method for manufacturing a substrate with a multilayer reflective film according to claim 1, characterized in that the first wavelength is longer than the second wavelength.

3. The method for manufacturing a multilayer reflective substrate according to claim 1 or 2, characterized in that the defect distance includes a value that takes into account the coordinate accuracy of the first defect inspection and the coordinate accuracy of the second defect inspection.

4. If there is a discrepancy defect between the first defect information and the second defect information, the discrepancy defect is treated as a defect in the first defect map based on the first mark coordinate RM1. A method for manufacturing a multilayer reflective substrate according to any one of claims 1 to 3, characterized in that if there is a matching defect between the first defect information and the second defect information, the matching defect is a defect in the second defect map based on the second mark coordinate RM2.

5. If there is a discrepancy between the first defect information and the second defect information, the process includes identifying a first discrepancy that is detected only in the first defect inspection and a second discrepancy that is detected only in the second defect inspection. The process further includes a step of performing a third defect inspection on the substrate with the multilayer reflective film, which is different from the first defect inspection and the second defect inspection. The third defect inspection includes measuring the dimensions of at least one of the matching defects and the first mismatched defects, A method for manufacturing a substrate with a multilayer reflective film according to any one of claims 1 to 4, characterized in that the defect dimensions measured in the third defect inspection are added to the third defect information.

6. A method for manufacturing a multilayer reflective substrate according to any one of claims 1 to 5, characterized in that the multilayer reflective substrate further includes a protective film on the multilayer reflective film.

7. A reflective mask blank characterized by having a multilayer reflective substrate manufactured by a method for manufacturing a multilayer reflective substrate according to any one of claims 1 to 6, and an absorber film formed on the multilayer reflective substrate.

8. The reflective mask blank according to claim 7, characterized in that the absorbent membrane includes a second reference mark FM formed on the absorbent membrane and a transfer reference mark RM' on which the reference mark RM is transferred to the absorbent membrane.

9. If there is a discrepancy defect between the first defect information and the second defect information of the reflective mask blank according to claim 7 or 8, the steps include identifying a first discrepancy defect that is detected only in the first defect inspection and a second discrepancy defect that is detected only in the second defect inspection, The process further includes a step of performing a third defect inspection on the reflective mask blank at a third wavelength different from the first and second wavelengths, The third defect inspection includes measuring the dimensions of at least one of the matching defects and the first mismatched defects transferred to the absorber membrane. A method for manufacturing a reflective mask blank, characterized in that the defect dimensions measured in the third defect inspection are added to the third defect information.

10. A method for manufacturing a reflective mask, characterized by patterning the absorbent film of a reflective mask blank manufactured by the method for manufacturing a reflective mask blank according to claim 7 or 8, or the method for manufacturing a reflective mask blank according to claim 9, to form an absorbent pattern.

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