Reflective mask blank, reflective mask, and method for manufacturing reflective mask

Abstract

The purpose of the present invention is to provide: a reflective mask for patterning transfer, which uses light having a wavelength in the extreme ultraviolet region as a light source and which is provided with an absorptive film having resistance to hydrogen radicals, and a reflective mask blank used for manufacturing the reflective mask; and a method for manufacturing the reflective mask using the reflective mask blank. A reflective photomask blank (10) according to the present embodiment comprises: a substrate (1); a reflective layer (2) which is formed on the substrate (1) and reflects EUV light; and an absorptive layer (4) which is formed on the reflective layer (2) and absorbs the EUV light. The absorptive layer (4) contains platinum (Pt) in the largest amount among all the elements constituting the absorptive layer (4), and, apart from the platinum (Pt), also contains at least one element selected from a first material group. The film density of the absorptive layer (4) is 9.0 g / cm3 or more.

Description

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

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

[0002] In the manufacturing process of semiconductor devices, the miniaturization of semiconductor devices has led to an increasing demand for miniaturization of photolithography technology. The minimum resolution dimension of a transfer pattern in photolithography is highly dependent on the wavelength of the exposure light source, and the shorter the wavelength, the smaller the minimum resolution dimension. For this reason, the exposure light source has been replaced from the conventional 193 nm wavelength ArF excimer laser light to light in the EUV (Extreme Ultra Violet) region with a wavelength of 13.5 nm.

[0003] Since light in the EUV region is absorbed at a high rate by most materials, a reflective photomask is used as a photomask for EUV exposure (EUV mask) (see, for example, Patent Document 1). Patent Document 1 discloses an EUV photomask obtained by forming a reflective layer made of a multilayer film in which molybdenum (Mo) layers and silicon (Si) layers are alternately stacked on a glass substrate, forming a light absorbing layer mainly composed of tantalum (Ta) thereon, and forming a pattern on this light absorbing layer.

[0004] Furthermore, as mentioned above, EUV lithography cannot use refractive optical systems that utilize the transmission of light, and therefore the optical components of the exposure machine are reflective (mirrors) rather than lenses. This poses the problem that the light incident on the reflective photomask (EUV mask) and the light reflected from the EUV mask cannot be designed to be coaxial. Normally, EUV lithography employs a method in which the optical axis is tilted 6 degrees from the perpendicular direction of the EUV mask, and the reflected light reflected at an angle of minus 6 degrees is guided onto the semiconductor substrate.

[0005] As described above, in EUV lithography, the optical axis is tilted via a mirror, which can cause a problem known as the "shadow effect," in which the EUV light incident on the EUV mask casts a shadow on the mask pattern (patterned light-absorbing layer) of the EUV mask. Current EUV mask blanks use a tantalum (Ta)-based film with a thickness of 60 to 90 nm as the light-absorbing layer. When pattern transfer exposure is performed using an EUV mask fabricated using this mask blank, depending on the relationship between the incident direction of the EUV light and the orientation of the mask pattern, a decrease in contrast may occur at the edge portions of the mask pattern that are shadowed. This can lead to problems such as increased line edge roughness of the transferred pattern on the semiconductor substrate and an inability to form the desired line width, resulting in a deterioration in transfer performance.

[0006] Therefore, studies have been conducted on a reflective photomask blank in which the light absorption layer is changed from tantalum (Ta) to a material having a high absorbency (extinction coefficient) for EUV light, or a material with high absorbency is added to tantalum (Ta). For example, Patent Document 1 describes a reflective photomask blank in which the light absorption layer is made of a material containing 50 atomic % (at %) or more of Ta as a main component and further containing at least one element selected from Te, Sb, Pt, I, Bi, Ir, Os, W, Re, Sn, In, Po, Fe, Au, Hg, Ga, and Al.

[0007] Furthermore, it is known that mirrors are contaminated by by-products (e.g., Sn) and carbon caused by EUV irradiation. Accumulation of contaminants on the mirror reduces the reflectivity of the mirror surface, lowering the throughput of the lithography apparatus. To address this problem, Patent Document 2 discloses a method for generating hydrogen radicals within the apparatus, causing the hydrogen radicals to react with the contaminants, and removing the contaminants from the mirror. As described above, materials used for reflective photomask blanks and reflective photomasks are required to have high resistance to hydrogen radicals.

[0008] However, some materials that are highly absorptive of EUV light have low resistance to hydrogen radicals, and there has been a problem in that a reflective mask made of a material with low resistance to hydrogen radicals cannot withstand long-term use.

[0009] Japanese Patent No. 4926523 Japanese Patent Application Laid-Open No. 2011-530823

[0010] The present disclosure has been made in light of the above circumstances, and aims to provide a reflective mask for patterning transfer that uses light with a wavelength in the extreme ultraviolet region as a light source, the reflective mask having an absorbing film that is resistant to hydrogen radicals, a reflective mask blank used to manufacture the reflective mask, and a method for manufacturing a reflective mask using the reflective mask blank.

[0011] The present disclosure has been made to solve the above-mentioned problems. A reflective mask blank according to one aspect of the present disclosure comprises a substrate, a reflective layer formed on the substrate and reflecting EUV light, and an absorbing layer formed on the reflective layer and absorbing EUV light, wherein the absorbing layer contains platinum (Pt) in the largest amount of all elements constituting the absorbing layer and also contains at least one or more elements selected from a first material group other than the platinum (Pt), and the absorbing layer has a film density of 9.0 g / cm ３ The present invention is characterized in that:

[0012] A reflective mask according to an aspect of the present disclosure includes a substrate, a reflective layer formed on the substrate and reflecting EUV light, and a patterned absorbing layer formed on the reflective layer and absorbing EUV light, wherein the absorbing layer contains platinum (Pt) in the largest amount among elements constituting the absorbing layer and also contains at least one or more elements selected from a first material group other than the platinum (Pt), and the absorbing layer has a film density of 9.0 g / cm ３ The present invention is characterized in that:

[0013] A method for manufacturing a reflective mask according to an aspect of the present disclosure includes the steps of forming a reflective layer that reflects EUV light on a substrate, and forming a patterned absorbing layer that absorbs EUV light on the reflective layer, wherein the absorbing layer contains platinum (Pt) in the largest amount among elements constituting the absorbing layer and also contains at least one or more elements selected from a first material group other than the platinum (Pt), and the absorbing layer has a film density of 9.0 g / cm ３ The present invention is characterized in that:

[0014] The reflective mask blank according to one embodiment of the present disclosure provides sufficient hydrogen radical resistance, making it possible to create an absorption layer. That is, the reflective mask blank according to one embodiment of the present disclosure can provide a reflective mask blank having high hydrogen radical resistance. Furthermore, the reflective mask according to one embodiment of the present disclosure can provide a reflective mask having high hydrogen radical resistance. Furthermore, the manufacturing method for a reflective mask according to one embodiment of the present disclosure can provide a reflective mask having high hydrogen radical resistance.

[0015] Thus, one aspect of the present disclosure can provide a reflective mask for patterning transfer that uses light with a wavelength in the extreme ultraviolet region as a light source, the reflective mask having an absorption film that is resistant to hydrogen radicals, a reflective mask blank used to manufacture the reflective mask, and a method for manufacturing a reflective mask using the reflective mask blank.

[0016] 1 is a cross-sectional view schematically showing the configuration of a reflective photomask blank according to an embodiment of the present invention; 2 is a cross-sectional view schematically showing the configuration of a reflective photomask according to an embodiment of the present invention; 3 is a graph showing the optical constants of each metal at the wavelength of EUV light;

[0017] As a result of extensive research, the present inventors have discovered a new absorber layer that contains platinum (Pt) in the largest amount among all elements constituting the absorber layer, and also contains other elements (at least one element selected from the first material group) other than platinum (Pt), and further has a film density of 9.0 g / cm ３The above has made it clear that the absorbing layer has excellent hydrogen radical resistance. In other words, the present disclosure proposes and provides a new design concept for improving the hydrogen radical resistance of the absorbing layer. This point will be explained below. In conventional design concepts, in order to improve the hydrogen radical resistance of the absorbing layer, attention has been focused on the elements that constitute the absorbing layer, and the type, content, composition ratio, etc. of the elements have been adjusted.

[0018] In response to this, the present inventors have discovered that by specifying platinum (Pt) as the main element (the element with the highest content) constituting the absorbing layer and setting the film density of the absorbing layer to a specific value, it is possible to impart excellent hydrogen radical resistance to the absorbing layer. In other words, the present inventors have newly discovered that in order to impart excellent hydrogen radical resistance to the absorbing layer, not only the constituent elements of the absorbing layer but also the film density of the absorbing layer are important. As such, the design concept in the present disclosure is significantly different from conventional design concepts that focus only on the constituent elements of the absorbing layer.

[0019] An embodiment of the present invention will be described with reference to the drawings. The configurations shown in the drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, and the like differ from the actual configurations. Furthermore, the embodiments shown below are merely examples of configurations that embody the technical concept of the present invention, and the technical concept of the present invention is not limited to the materials, shapes, structures, and the like of the components described below. Various modifications can be made to the technical concept of the present invention within the technical scope defined by the claims.

[0020] (Configuration of Reflective Photomask Blank and Reflective Photomask) FIG. 1 is a schematic cross-sectional view showing the structure of a reflective photomask blank (reflective mask blank) 10 according to an embodiment of the present invention. As shown in FIG. 1, the reflective photomask blank 10 according to an embodiment of the present invention comprises a substrate 1, a reflective layer 2 formed on the substrate 1 and having, for example, a multilayer film structure, which reflects EUV light, a protective layer (capping layer) 3 formed on the reflective layer 2, and an absorption layer 4 formed on the protective layer 3 and which absorbs EUV light. The reflective layer 2 and the protective layer (capping layer) 3 form a reflective section 5. The reflective photomask (reflective mask) 20 according to an embodiment of the present invention is fabricated by forming a transfer pattern in the reflective layer 2 of the reflective photomask blank 10 according to an embodiment of the present invention. Each layer constituting the reflective photomask blank 10 according to an embodiment of the present invention will be described in detail below.

[0021] (Substrate) For example, a flat Si substrate or a synthetic quartz substrate can be used for the substrate 1 according to the embodiment of the present invention. Furthermore, low-thermal expansion glass containing added titanium can be used for the substrate 1, but the present invention is not limited to these materials as long as they have a low thermal expansion coefficient. Furthermore, although not shown, a back surface conductive film can be formed on the surface of the substrate 1 on which the reflective layer 2 is not formed. The back surface conductive film is a film for fixing a reflective photomask manufactured using the reflective photomask blank 10 according to the embodiment of the present invention using the principle of an electrostatic chuck when the reflective photomask is installed in an exposure machine.

[0022] (Reflective Layer) The reflective layer 2 according to the embodiment of the present invention may be any layer that reflects EUV light (extreme ultraviolet light), which is exposure light, and may be a multilayer reflective film made of a combination of materials that have significantly different refractive indices for EUV light (i.e., an EUV light reflective film having a multilayer film structure). The reflective layer 2 including a multilayer reflective film may be formed by repeatedly stacking layers of a combination of, for example, Mo (molybdenum) and Si (silicon), or Mo (molybdenum) and Be (beryllium), for example, for about 40 periods.

[0023] (Protective Layer) The protective layer 3 according to the embodiment of the present invention is a layer that functions as an etching stopper that prevents damage to the reflective layer 2 when the absorbing layer 4 is etched during photomask fabrication. Note that the protective layer 3 may not be formed depending on the material of the reflective layer 2 and the etching conditions. The protective layer 3 is formed of a material that is resistant to dry etching that is performed during pattern formation of the absorbing layer 4. For example, the material of the protective layer 3 may be ruthenium (Ru).

[0024] (Absorbing Layer) As shown in Fig. 1, the absorbing layer 4 is a layer formed on the protective layer 3, and is a layer that absorbs EUV light, which is the exposure light. Furthermore, since the reflective photomask 20 in Fig. 2 is exposed to a hydrogen radical environment, the reflective photomask 20 cannot withstand long-term use unless the absorbing layer 4 is formed from a light-absorbing material that is highly resistant to hydrogen radicals. In this embodiment, a material with high hydrogen radical resistance is defined as a material that exhibits a film reduction rate of 0.1 nm / s or less in a hydrogen radical environment using microwave plasma at a power of 1 kW and a hydrogen pressure of 0.36 millibars (mbar) or less.

[0025] Resistance is significantly increased and the above-mentioned standard for hydrogen radical resistance can be satisfied by using platinum (Pt) as the main material constituting the absorbing layer 4, that is, by making the content (atomic %) of platinum (Pt) the highest among all elements constituting the absorbing layer 4. This is thought to be because mixing platinum (Pt), which has resistance to hydrogen radicals, increases strength and contributes to improving the stability of the compound.

[0026] Regarding the criteria for hydrogen radical resistance, in the evaluation test of the film loss rate shown in Table 1, the film loss rate was measured multiple times, and if the film loss rate was 0.1 nm / s or less in all of the measurements, it was evaluated as "◎", if there was variation in the film loss rate but the film loss rate was 0.1 nm / s or less in more than half of the measurements, it was evaluated as "◯", and if the film loss rate was more than 0.1 nm / s in all of the measurements, it was evaluated as "×". In this embodiment, if the evaluation is "◯", there is no problem in use, but if the evaluation is "◎", it is more preferable in use.

[0027] The absorption layer 4 in this embodiment is formed of a material containing platinum (Pt) as a main material, and the film density of the absorption layer 4 is 9.0 g / cm ３ That is, the absorbing layer 4 in this embodiment contains platinum (Pt) in the largest amount among all elements (atomic %) constituting the absorbing layer 4, and the film density of the absorbing layer 4 is 9.0 g / cm ３ The film density of the absorption layer 4 is 9.0 g / cm ３ If the film density is less than 22.0 g / cm, the bonding is unstable and minute cavities exist inside the film, so that sufficient resistance to hydrogen radicals may not be obtained. Also, sufficient absorption performance against EUV light may not be obtained. On the other hand, although there is no particular upper limit to the film density of the absorption layer 4, the higher the film density, the more difficult it tends to be to process it by dry etching. In particular, if the film density is 22.0 g / cm, ３ If the film density of the absorbing layer 4 exceeds 9.0 g / cm, dry etching processability tends to become difficult. Therefore, in order to obtain excellent hydrogen radical resistance and excellent dry etching processability, the film density of the absorbing layer 4 should be 9.0 g / cm ３ It is preferable that the density is 10.0 g / cm or more. ３ 22.0g / cm or more ３ It is more preferable that the range is 11.0 g / cm ３ 20.0g / cm or more ３ It is more preferable that the content is within the following range.

[0028] In this embodiment, the film density of the absorber layer 4 can be adjusted to a desired value by adjusting the composition ratio of platinum (Pt) to at least one element selected from the first material group described below. The film density of the absorber layer 4 may be calculated from the measurement results of Rutherford backscattering spectroscopy (RBS), for example. The measurement conditions for calculating the film density using Rutherford backscattering spectroscopy (RBS) are shown below. Incident ions: 2.275 MeV 4He++ Beam diameter: 1 to 2 mmφ RBS detection angle: Normal angle 160 degrees; Grazing angle ~108 degrees

[0029] The outermost surface of the absorbing layer 4 may be oxidized by natural oxidation due to reaction with oxygen in the atmosphere or by undergoing a blank preparation process such as cleaning treatment. The absorbing layer 4 may also have a gradient structure in which the components thereof change stepwise from the surface layer toward the substrate 1. In other words, the absorbing layer 4 may have a gradient structure in which the concentrations of the components thereof change stepwise from the outermost surface side toward the substrate 1 side.

[0030] The material constituting the absorber layer 4 includes platinum (Pt) and one or more elements selected from a first material group described below. That is, the absorber layer 4 includes platinum (Pt) as a primary material and also includes one or more elements selected from the first material group. Here, the "primary material" refers to an element (material) that accounts for 51 atomic % or more of all the metal elements constituting the absorber layer 4. In other words, 51 atomic % or more of all the metal elements constituting the absorber layer 4 are platinum (Pt), and the content of one or more elements selected from the first material group is 49 atomic % or less. That is, the lower limit of the platinum (Pt) content of the absorber layer 4 is 51 atomic % of all the metal elements constituting the absorber layer 4, and the upper limit of the content of one or more elements selected from the first material group is 49 atomic % of all the metal elements constituting the absorber layer 4. When the respective contents of platinum (Pt) and one or more elements selected from the first material group are within the above-described ranges, the absorber layer 4 is provided with hydrogen radical resistance and can minimize the influence of the shadowing effect.

[0031] The upper limit of the content of platinum (Pt) contained in the absorption layer 4 is not particularly limited, but is 99 atomic % with respect to all metal elements constituting the absorption layer 4. The lower limit of the content of one or more elements selected from the first material group is not particularly limited, but is 1 atomic % with respect to all metal elements constituting the absorption layer 4.

[0032] In this embodiment, the first material group is preferably composed of at least one element selected from niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), nickel (Ni), cobalt (Co), bismuth (Bi), iron (Fe), gold (Au), palladium (Pd), rhenium (Re), tin (Sn), oxygen (O), nitrogen (N), and boron (B), and more preferably composed of at least one element selected from niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), oxygen (O), nitrogen (N), and boron (B). In this embodiment, the first material group may also contain carbon (C).

[0033] When the first material group is composed of at least one element selected from niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), nickel (Ni), cobalt (Co), bismuth (Bi), iron (Fe), gold (Au), palladium (Pd), rhenium (Re), tin (Sn), oxygen (O), nitrogen (N), and boron (B), the hydrogen radical resistance and smoothness of the absorption layer 4 are appropriately balanced, and excellent film properties can be obtained compared to when other elements are used.

[0034] Furthermore, when the first material group is composed of at least one element selected from niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), oxygen (O), nitrogen (N), and boron (B), the absorber layer 4 can have a more excellent film property by appropriately balancing the hydrogen radical resistance and smoothness compared to the case where other elements are used. Furthermore, the content of non-metallic elements among the elements belonging to the first material group is preferably in the range of 0 atomic % to 25 atomic % of all elements constituting the absorber layer 4, more preferably in the range of 0 atomic % to 20 atomic % of all elements constituting the absorber layer 4, and even more preferably in the range of 0 atomic % to 15 atomic % of all elements constituting the absorber layer 4.

[0035] Furthermore, although the film density is usually determined by the ratio of alloy species, the present inventors have found that the density of the absorbing layer 4 can be increased by introducing a light element (e.g., O, N, B, C, etc.) that can acquire high binding energy into the absorbing layer 4. Furthermore, the present inventors have found that the density of the absorbing layer 4 can be easily adjusted by adjusting the amount of the light element introduced (added amount) into the absorbing layer 4.

[0036] For example, when the amount of the light element introduced is 0.001 atomic % to 1.0 atomic % of all elements constituting the absorption layer 4, the film density of the absorption layer 4 increases in the range of 1% to 3%. Specifically, when the light element introduced into the absorption layer 4 is 5 atomic % or more, the density of the absorption layer 4 tends to decrease, but when the amount of the light element introduced into the absorption layer 4 is extremely small, such as 0.001 atomic % to 1.0 atomic %, the density of the absorption layer 4 tends to increase. In other words, there is no strict proportional relationship between the composition of the absorption layer 4 (specifically, the amount of the light element introduced) and the density of the absorption layer 4.

[0037] The film density of the absorption layer 4 may be calculated, for example, from the measurement results of X-ray reflectometry (XRR). The measurement conditions for calculating the film density using X-ray reflectometry (XRR) are shown below. Incident X-ray: Cu Kα ray (wavelength 1.54 Å) X-ray reflection angle: range of 0.2 degrees to 5 degrees Measurement scan speed: 0.02 degrees / second Detector: scintillation counter Data analysis: fitting is performed from the reflectivity profile to calculate the film thickness, roughness, and film density. This measurement makes it possible to evaluate the film density with high precision.

[0038] The film density and element distribution of the absorption layer 4 may be calculated from the measurement results of, for example, secondary ion mass spectrometry (SIMS). The measurement conditions for measuring the film density or element distribution using secondary ion mass spectrometry (SIMS) are shown below. Incident ions: Cs ＋ ions (energy 5.0 keV) or O ２ ＋ Ions (energy 10.0 keV) Beam diameter: 50 nm to 200 nm Sputtering rate: 0.1 nm / s to 1.0 nm / s Mass analyzer: quadrupole mass analyzer or time-of-flight mass analyzer (TOF-SIMS) Detection mass range: 1 to 300 amu Measurement target: Estimation of element concentration profile in the depth direction and film density.

[0039] As described above, by introducing light elements such as oxygen (O), nitrogen (N), boron (B), and carbon (C) into the absorber layer 4, the density of the absorber layer 4 can be easily and accurately increased. Furthermore, by adjusting the amount of the light elements introduced within a range of 0.001 atomic % to 1.0 atomic % with respect to all elements constituting the absorber layer 4, the density of the absorber layer 4 can be easily and accurately adjusted. Furthermore, by adjusting the amount of the light elements introduced within a range of 0.001 atomic % to 1.0 atomic % with respect to all elements constituting the absorber layer 4, the density of the absorber layer 4 can be increased to 9.0 g / cm ３ The absorbent layer 4 adjusted as described above can be endowed with excellent hydrogen radical resistance and excellent smoothness.

[0040] The absorption layer 4 preferably contains 51 atomic % or more, more preferably 60 atomic % or more, and even more preferably 70 atomic % or more of platinum (Pt) among the metal elements excluding non-metal elements among the elements constituting the absorption layer 4. When the absorption layer 4 contains 51 atomic % or more of platinum (Pt) among the metal elements excluding non-metal elements among the elements constituting the absorption layer 4, the influence of the projection effect can be reduced compared to when other elements are used.

[0041] Furthermore, if the absorption layer 4 contains 60 atomic % or more of platinum (Pt) among the metal elements excluding non-metal elements among the elements constituting the absorption layer 4, the influence of the projection effect can be further reduced compared to when other elements are used. Furthermore, if the absorption layer 4 contains 70 atomic % or more of platinum (Pt) among the metal elements excluding non-metal elements among the elements constituting the absorption layer 4, the influence of the projection effect can be further reduced compared to when other elements are used.

[0042] The above composition ratios of the materials constituting the absorber layer 4 are calculated based on the results of analysis by Rutherford backscattering spectroscopy (RBS), and the contents may vary depending on the analysis method. For example, a material whose platinum (Pt) content is 51 atomic % to 99 atomic % of all metal elements as analyzed by RBS may be found to have a platinum (Pt) content of 40 atomic % to 75 atomic % of all metal elements as analyzed by X-ray photoelectron spectroscopy (XPS), or may be found to have a platinum content of 45 atomic % to 100 atomic % of all metal elements as analyzed by energy dispersive X-ray spectroscopy (EDX). To achieve transferability equal to or better than that of conventional EUV masks having a light-absorbing film with a thickness of 60 to 90 nm and primarily composed of Ta, the absorber layer 4 preferably has a thickness of less than 60 nm.

[0043] Furthermore, in order to obtain transferability equivalent to or better than that of conventional EUV masks having a light-absorbing film primarily composed of Ta and having a thickness of 60 to 90 nm, the thickness of the absorbing layer 4 is preferably 55 nm or less. Furthermore, in order to obtain transferability equivalent to or better than that of conventional EUV masks having a light-absorbing film primarily composed of Ta and having a thickness of 60 to 90 nm, the thickness of the absorbing layer 4 is preferably 45 nm or less. If the thickness of the absorbing layer 4 is less than 60 nm, the projection effect (shadowing) is suppressed, and superior transferability compared to existing films can be obtained. The above-described configuration makes it possible to provide a reflective photomask blank 10 and a reflective photomask 20 for patterning transfer using light with wavelengths in the extreme ultraviolet region as a light source, which are provided with an absorbing film that is resistant to hydrogen radicals.

[0044] 2, the intensity of the reflected light from the reflective portion 5 is Rm, and the intensity of the reflected light from the absorbing layer 4 is Ra. The optical density (OD) value, which is an index representing the contrast in light intensity between the reflective portion 5 and the absorbing layer 4, is defined by the following formula 1: OD=-log(Ra / Rm) (Formula 1)

[0045] The larger the OD value, the better the contrast and the higher the transferability. For pattern transfer, OD>1 is preferable, and 1.5 or more is more preferable. In this embodiment, the OD value of the absorbing layer 4 is preferably 1.0 or more, and 1.5 or more is more preferable. If the OD value of the absorbing layer 4 is 1.0 or more, sufficient contrast can be obtained, and the transferability required for use can be obtained.

[0046] The material constituting the absorption layer 4 may also contain a material (element) other than platinum (Pt) and the elements of the first material group. The material constituting the absorption layer 4 may contain, for example, beryllium (Be), calcium (Ca), scandium (Sc), vanadium (V), manganese (Mn), copper (Cu), germanium (Ge), arsenic (As), strontium (Sr), technetium (Tc), rhodium (Rh), barium (Ba), rhenium (Re), osmium (Os), boron (B), nitrogen (N), oxygen (O), or the like, thereby making the material sufficiently amorphous. Forming the absorption layer 4 from an amorphous material can improve roughness, in-plane dimensional uniformity, and in-plane uniformity of the transferred image.

[0047] Furthermore, when the material constituting the absorbing layer 4 contains, for example, zirconium (Zr), hafnium (Hf), yttrium (Y), lead (Pb), gallium (Ga), etc., the material is less likely to react with hydrogen radicals and can be made more resistant to hydrogen radicals. Furthermore, when the material constituting the absorbing layer 4 contains, for example, chromium (Cr), aluminum (Al), etc., an oxide film that is resistant to hydrogen radicals can be formed so as to cover the exposed surface of the absorbing layer 4 when the absorbing layer 4 is patterned to produce a photomask.

[0048] Furthermore, by including, for example, silicon nitride (SiN), tantalum oxide (TaO), or the like, the material constituting the absorption layer 4 can be made to have high light absorption at wavelengths of 190 nm to 260 nm and improve the contrast of inspection light. Furthermore, by including, for example, cobalt (Co), palladium (Pd), molybdenum (Mo), silver (Ag), or the like, the material constituting the absorption layer 4 can be made to have a refractive index n of less than 0.95 at a wavelength of 13.5 nm and improve phase shift properties. Furthermore, by including, for example, tellurium (Te), tin (Sn), nickel (Ni), or the like, the material constituting the absorption layer 4 can be made to have a high extinction coefficient and be able to reduce the projection effect.

[0049] The above describes an example of the effects of materials that can be contained in the absorption layer 4, but the effects of each material are not limited to the above example and may correspond to multiple effects. As shown in Figure 3, the absorption layer 4 can be made of a material that can reduce the projection effect by increasing the composition ratio of platinum (Pt), which has a relatively large extinction coefficient k, i.e., by increasing the platinum (Pt) content. Furthermore, by appropriately adjusting the composition ratio of platinum (Pt) in the absorption layer 4 and increasing the refractive index n, it is possible to make it a material with a high phase shift effect.

[0050] (Method for manufacturing a reflective photomask) A method for manufacturing a reflective photomask 20 according to an embodiment of the present disclosure includes the steps of forming a reflective layer 2 that reflects EUV light on a substrate 1, and forming a patterned absorbing layer 4 that absorbs EUV light on the reflective layer 2, wherein the absorbing layer 4 contains platinum (Pt) in the largest amount among the elements constituting the absorbing layer 4, and also contains at least one or more elements selected from a first material group other than platinum (Pt), and the absorbing layer 4 has a film density of 9.0 g / cm ３ That's all.

[0051] That is, the method for manufacturing a reflective photomask 20 according to an embodiment of the present disclosure includes a step of forming a reflective layer 2 that reflects EUV light on a substrate 1, and a step of forming a patterned absorbing layer 4 that absorbs EUV light on the reflective layer 2. In the step of forming the absorbing layer 4, the absorbing layer 4 is formed from platinum (Pt) and at least one element selected from a first material group, and is formed so that the content (atomic %) of platinum (Pt) is the highest among the elements constituting the absorbing layer 4, and further, the film density of the absorbing layer 4 is 9.0 g / cm ３ The above manufacturing method can provide a reflective photomask 20 that is a reflective photomask for patterning transfer using light with a wavelength in the extreme ultraviolet region as a light source and that is provided with an absorbing film that is resistant to hydrogen radicals.

[0052] As described above, the present invention provides a semiconductor device comprising at least the substrate 1, the reflective layer 2 formed on the substrate 1 and having, for example, a multilayer film structure, which reflects EUV light, and the absorbing layer 4 formed on the reflective layer 2 and which absorbs EUV light, the absorbing layer 4 containing platinum (Pt) as a main material and containing one or more elements selected from the first material group, and further the film density of the absorbing layer 4 being 9.0 g / cm ３ With the reflective photomask blank 10 described above, the smoothness and hydrogen radical resistance of the absorbing layer 4 are excellent.

[0053] EXAMPLES The present disclosure will be explained in more detail below with reference to examples, but the present disclosure is not limited to these examples in any way.

[0054] Example 1: A synthetic quartz substrate with low thermal expansion was used as the substrate. A multilayer reflective film (reflective layer) was formed on the substrate by stacking 40 layers of a laminate film consisting of a pair of silicon (Si) and molybdenum (Mo). The thickness of the multilayer reflective film was 280 nm. Next, a capping layer (protective layer) was formed on the multilayer reflective film using ruthenium (Ru) to a thickness of 3.5 nm. This resulted in a reflective portion having a multilayer reflective film and a capping layer on the substrate. An absorption layer made of platinum (Pt) and titanium (Ti) was formed on the capping layer.

[0055] Next, a backside conductive film was formed on the side of the substrate where the multilayer reflective film was not formed, using chromium nitride (CrN), to a thickness of 100 nm. In this way, a reflective photomask blank of Example 1 was produced. A multi-target sputtering device was used to form the film on the substrate. The composition of the metal elements in the absorber layer of Example 1 formed as described above was measured by Rutherford backscattering spectroscopy (RBS), and found to be 51 atomic % Pt and 49 atomic % Ti.

[0056] Next, a positive chemically amplified resist (SEBP9012: manufactured by Shin-Etsu Chemical Co., Ltd.) was spin-coated on the absorbing layer to a thickness of 120 nm and baked at 110°C for 10 minutes to form a resist film. Next, a predetermined pattern was written on the positive chemically amplified resist using an electron beam lithography machine (JBX3030: manufactured by JEOL Ltd.). After that, a baking process was performed at 110°C for 10 minutes, followed by spray development (SFG3000: manufactured by Sigma Meltec Co., Ltd.). This formed a resist pattern.

[0057] Next, using the resist pattern as an etching mask, the absorber layer was patterned by dry etching mainly using a chlorine-based gas to form an absorber layer pattern. Next, the remaining resist pattern was peeled off. Thus, an absorber layer pattern was formed in which the surface and side surfaces of the absorber layer were exposed. In this example, the absorber layer pattern was a line-and-space (LS) pattern with a line width of 64 nm. In this way, a reflective photomask according to Example 1 was produced.

[0058] Example 2 An absorbing layer made of platinum (Pt) and titanium (Ti) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 2 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 2 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 60 atomic % Pt and 40 atomic % Ti.

[0059] Example 3 An absorbing layer made of platinum (Pt) and titanium (Ti) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 3 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 3 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 70 atomic % Pt and 30 atomic % Ti.

[0060] Example 4 An absorbing layer made of platinum (Pt) and titanium (Ti) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 4 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 4 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 99 atomic % Pt and 1 atomic % Ti.

[0061] Example 5 Platinum (Pt) and titanium oxide (Ti) were deposited on the capping layer. ２ A reflective photomask blank and a reflective photomask of Example 5 were produced in the same manner as in Example 1, except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 5 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt, 51 atomic % Ti, and 51 atomic % Ti. ２ The O content (total of Ti and O) was 49 atomic %.

[0062] Example 6 An absorbing layer made of platinum (Pt) and niobium (Nb) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 6 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 6 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt and 49 atomic % Nb.

[0063] Example 7 An absorbing layer made of platinum (Pt) and chromium (Cr) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 7 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 7 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt and 49 atomic % Cr.

[0064] Example 8 An absorbing layer made of platinum (Pt) and ruthenium (Ru) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 8 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 8 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt and 49 atomic % Ru.

[0065] Example 9 An absorbing layer made of platinum (Pt) and nickel (Ni) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 9 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 9 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt and 49 atomic % Ni.

[0066] Example 10 An absorbing layer made of platinum (Pt) and cobalt (Co) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 10 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 10 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt and 49 atomic % Co.

[0067] Example 11 An absorbing layer made of platinum (Pt) and bismuth (Bi) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 11 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 11 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt and 49 atomic % Bi.

[0068] Example 12 An absorbing layer made of platinum (Pt) and gold (Au) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 12 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 12 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt and 49 atomic % Au.

[0069] Example 13 An absorbing layer made of platinum (Pt) and palladium (Pd) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 13 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 13 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt and 49 atomic % Pd.

[0070] Example 14 An absorbing layer made of platinum (Pt) and rhenium (Re) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 14 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 14 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt and 49 atomic % Re.

[0071] Example 15 Platinum (Pt) and indium nitride (In) were deposited on the capping layer. ３ N ２ ) was formed. A reflective photomask blank and a reflective photomask of Example 15 were produced in the same manner as in Example 1 except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 15 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt, 51 atomic % In, and 51 atomic % Pt. ３ N ２ (the total of In and N) was 49 atomic %.

[0072] Example 16 Platinum (Pt) and indium nitride (In) were deposited on the capping layer. ７ N ３A reflective photomask blank and a reflective photomask of Example 16 were produced in the same manner as in Example 1 except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 16 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 60 atomic % Pt, 10 atomic % In, and 10 atomic % Pt. ７ N ３ (the sum of In and N) was 40 atomic %.

[0073] Example 17 Platinum (Pt) and indium nitride (In) were deposited on the capping layer. ６ N ５ A reflective photomask blank and a reflective photomask of Example 17 were produced in the same manner as in Example 1 except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 17 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 60 atomic % Pt, 10 atomic % In, and 10 atomic % Pt. ６ N ５ (the sum of In and N) was 40 atomic %.

[0074] Example 18 An absorber layer made of platinum (Pt) and indium nitride (InN) was formed on the capping layer. Note that, except for the absorber layer, a reflective photomask blank and a reflective photomask of Example 18 were produced in the same manner as in Example 1. The composition of the metal elements in the absorber layer of Example 18 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 75 atomic % Pt and 25 atomic % InN (the sum of In and N).

[0075] Example 19 An absorbing layer made of platinum (Pt) and rhenium bismuth (BiRe) was formed on a multilayer reflective film without providing a capping layer. A reflective photomask blank and a reflective photomask of Example 19 were produced in the same manner as in Example 1, except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 19 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 40 atomic % Pt and 60 atomic % BiRe (the sum of Bi and Re).

[0076] Example 20: No capping layer was provided, and an absorbing layer made of platinum (Pt) and hafnium lead (HfPb) was formed on a multilayer reflective film. A reflective photomask blank and a reflective photomask of Example 20 were produced in the same manner as in Example 1, except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 20 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and found to be 40 atomic % Pt and 60 atomic % HfPb (the sum of Hf and Pb).

[0077] Example 21 Platinum (Pt) and hafnium lead (Hf) were deposited on the multilayer reflective film without providing a capping layer. ２ Pb ３ ) was formed. A reflective photomask blank and a reflective photomask of Example 21 were produced in the same manner as in Example 1 except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 21 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % Pt, 51 atomic % Hf ２ Pb ３ (total of Hf and Pb) was 49 atomic %.

[0078] Example 22 Platinum (Pt) and yttrium lead (Y) were deposited on the multilayer reflective film without providing a capping layer. ５ Pb ７ A reflective photomask blank and a reflective photomask of Example 22 were produced in the same manner as in Example 1 except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 22 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 40 atomic % Pt, 10 atomic % Y, and 10 atomic % Pt. ５ Pb ７ (the total of Y and Pb) was 60 atomic %.

[0079] Example 23 Platinum (Pt) and yttrium lead (Y) were deposited on the capping layer. ５ Pb ７A reflective photomask blank and a reflective photomask of Example 23 were produced in the same manner as in Example 1 except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 23 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 40 atomic % Pt, 10 atomic % Y, and 10 atomic % Pt. ５ Pb ７ (the total of Y and Pb) was 60 atomic %.

[0080] Example 24 An absorbing layer made of platinum (Pt), ruthenium, and nitrogen (Ru+N) was formed on the capping layer. A reflective photomask blank and a reflective photomask of Example 24 were produced in the same manner as in Example 1, except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 24 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and found to be 51 atomic % for Pt and 49 atomic % for the sum of Ru and N. Measurement by secondary ion mass spectroscopy (SIMS) revealed that N was 0.001 atomic %.

[0081] Example 25 An absorbing layer made of platinum (Pt), ruthenium, and nitrogen (Ru+N) was formed on the capping layer. A reflective photomask blank and a reflective photomask of Example 25 were produced in the same manner as in Example 1, except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 25 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and found to be 51 atomic % Pt and 49 atomic % in total Ru and N. Measurement by secondary ion mass spectroscopy (SIMS) revealed that N was 1 atomic %.

[0082] Example 26 An absorbing layer made of platinum (Pt), ruthenium, and nitrogen (Ru+N) was formed on the capping layer. A reflective photomask blank and a reflective photomask of Example 26 were produced in the same manner as in Example 1, except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 26 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and found to be 51 atomic % Pt and 49 atomic % in total Ru and N. Measurement by secondary ion mass spectroscopy (SIMS) revealed that N was 0.1 atomic %.

[0083] Example 27 An absorption layer composed of platinum (Pt), ruthenium, and boron (Ru+B) was formed on the capping layer. A reflective photomask blank and a reflective photomask of Example 27 were produced in the same manner as in Example 1, except for the absorption layer. The composition of the metal elements in the thus-formed absorption layer of Example 27 was measured by Rutherford backscattering spectroscopy (RBS), and found to be 51 atomic % Pt and 49 atomic % in total Ru and B. Measurement by secondary ion mass spectroscopy (SIMS) revealed that B was 0.1 atomic %.

[0084] Example 28 An absorbing layer made of platinum (Pt), ruthenium, and oxygen (RuO) was formed on the capping layer. A reflective photomask blank and a reflective photomask of Example 28 were produced in the same manner as in Example 1, except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 28 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and found to be 51 atomic % Pt and 49 atomic % in total of Ru and O. Measurement by secondary ion mass spectroscopy (SIMS) revealed that O was 0.1 atomic %.

[0085] Example 29 Without providing a capping layer, an absorbing layer made of platinum (Pt) and yttrium (Y) was formed on a multilayer reflective film. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 29 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 29 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 51 atomic % of Pt and 49 atomic % in total of Y.

[0086] Example 30: An absorbing layer made of platinum (Pt), yttrium, and carbon (Y+C) was formed on a multilayer reflective film without providing a capping layer. A reflective photomask blank and a reflective photomask of Example 30 were produced in the same manner as in Example 1, except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 30 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and found to be 51 atomic % Pt and 49 atomic % in total Y and C. Measurement by secondary ion mass spectroscopy (SIMS) revealed that C was 2 atomic %.

[0087] Example 31 An absorbing layer made of platinum (Pt), palladium, and carbon (Pd+C) was formed on the capping layer. A reflective photomask blank and a reflective photomask of Example 31 were produced using the same method as in Example 1, except for the absorbing layer. The composition of the metal elements in the absorbing layer of Example 31 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and found to be 51 atomic % Pt and 49 atomic % in total Pd and C. Measurement by secondary ion mass spectroscopy (SIMS) revealed that C was 2 atomic %.

[0088] Example 32 An absorbing layer made of platinum (Pt) and ruthenium (Ru) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 32 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 32 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 60 atomic % Pt and 40 atomic % Ru.

[0089] Example 33 An absorbing layer made of platinum (Pt) and ruthenium (Ru) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 33 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 33 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 70 atomic % Pt and 30 atomic % Ru.

[0090] Example 34 An absorbing layer made of platinum (Pt) and ruthenium (Ru) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Example 34 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Example 34 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 99 atomic % Pt and 1 atomic % Ru.

[0091] Comparative Example 1 An absorbing layer made of platinum (Pt) and titanium (Ti) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Comparative Example 1 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Comparative Example 1 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 19 atomic % Pt and 81 atomic % Ti.

[0092] Comparative Example 2 An absorbing layer made of platinum (Pt) and titanium (Ti) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Comparative Example 2 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Comparative Example 2 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 29 atomic % Pt and 71 atomic % Ti.

[0093] Comparative Example 3 An absorbing layer made of platinum (Pt) and bismuth (Bi) was formed on the capping layer. Note that, except for the absorbing layer, a reflective photomask blank and a reflective photomask of Comparative Example 3 were produced in the same manner as in Example 1. The composition of the metal elements in the absorbing layer of Comparative Example 3 thus formed was measured by Rutherford backscattering spectroscopy (RBS), and was found to be 70 atomic % Pt and 30 atomic % Bi.

[0094] The evaluation items for the reflective photomask blanks obtained in Examples 1 to 34 and Comparative Examples 1 to 3 will be described below.

[0095] (Film Density Evaluation) Film density was evaluated on the basis of the results of measurement by Rutherford backscattering spectroscopy (RBS) using the following four levels of "◎", "◯", "Δ" and "×".

[0096] <Evaluation criteria> ⊚: Film density is 11.0 g / cm ３ ○: Film density is 10.0 g / cm or more ３ 11.0g / cm or more ３ △: When the film density is less than 9.0 g / cm ３ 10.0g / cm or more ３ ×: When the film density is less than 9.0 g / cm ３ If it is less than

[0097] (Evaluation of Hydrogen Radical Resistance) The samples were irradiated with hydrogen radicals using microwave plasma at a power of 1 kW and a hydrogen pressure of 0.36 millibars (mbar) or less. Then, the etching rate of the absorbing layer due to immersion in the cleaning solution was calculated by measuring the film thickness using an atomic force microscope, and the results were evaluated using the following three levels: "◎", "◯", and "×". In this evaluation, the etching rate was calculated for multiple samples for each example and comparative example.

[0098] <Evaluation Criteria> ⊚: When the film reduction rate is 0.1 nm / s or less in all measurement results ◯: When the film reduction rate is 0.1 nm / s or less in half or more measurement results ×: When the film reduction rate is more than 0.1 nm / s in all measurement results Regarding hydrogen radical resistance, if the evaluation is "◎" or "◯", there is no problem in using the reflective photomask blank, and therefore it was judged to be "passed".

[0099] From the above results, it became clear that there is a certain relationship between the film thickness reduction rate of the absorber layer due to hydrogen radical irradiation and the film density of the absorber layer. Regarding the relationship between the film thickness reduction rate of the absorber layer and the film density of the absorber layer, when the film thickness reduction rate of the absorber layer due to hydrogen radical irradiation is low, the film density of the absorber layer tends to be high. The above evaluation results are shown in Table 1. The "film thickness" shown in Table 1 was measured using a known film thickness meter. The "film thickness" shown in Table 1 means the total thickness of the absorber layer.

[0100]

[0101] As described above, the present invention comprises a substrate 1, a reflective layer 2 formed on the substrate 1 and reflecting EUV light, and an absorbing layer 4 formed on the reflective layer 2 and absorbing EUV light, the absorbing layer 4 containing platinum (Pt) in the largest amount among all elements constituting the absorbing layer 4, and containing at least one or more elements selected from a first material group other than platinum (Pt), and the absorbing layer 4 has a film density of 9.0 g / cm ３ The above-described reflective photomask blank and a reflective photomask formed using the reflective photomask blank can provide a reflective photomask blank and a reflective photomask for patterning transfer that are equipped with an absorption film that is resistant to hydrogen radicals and that uses light with a wavelength in the extreme ultraviolet region as a light source.

[0102] Furthermore, for example, the present invention can be configured as follows: (1) A substrate, a reflective layer formed on the substrate and reflecting EUV light, and an absorbing layer formed on the reflective layer and absorbing EUV light, wherein the absorbing layer contains platinum (Pt) in the largest amount of all elements constituting the absorbing layer, and contains at least one or more elements selected from a first material group other than the platinum (Pt), and the absorbing layer has a film density of 9.0 g / cm ３(2) A reflective mask blank according to (1) above, characterized in that the first material group consists of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), nickel (Ni), cobalt (Co), bismuth (Bi), iron (Fe), gold (Au), palladium (Pd), rhenium (Re), tin (Sn), oxygen (O), nitrogen (N), and boron (B). (3) A reflective mask blank according to (1) above, characterized in that the first material group consists of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), oxygen (O), nitrogen (N), and boron (B). (4) The reflective mask blank according to any one of (1) to (3) above, characterized in that the absorber layer contains 51 atomic % or more of platinum (Pt) among the metal elements contained in the absorber layer. (5) The reflective mask blank according to any one of (1) to (3) above, characterized in that the absorber layer contains 60 atomic % or more of platinum (Pt) among the metal elements contained in the absorber layer. (6) The reflective mask blank according to any one of (1) to (3) above, characterized in that the absorber layer contains 70 atomic % or more of platinum (Pt) among the metal elements contained in the absorber layer. (7) The reflective mask blank according to any one of (1) to (3) above, characterized in that the absorber layer has a film density of 9.5 g / cm ３ (8) The reflective mask blank according to any one of the above (1) to (6), wherein the absorbing layer has a film density of 10.0 g / cm or more. ３(9) A reflective mask blank according to any one of (1) to (6) above, characterized in that the absorbing film has a thickness of less than 60 nm. (10) A reflective mask blank according to any one of (1) to (8) above, characterized in that the absorbing film has a thickness of 55 nm or less. (11) A reflective mask blank according to any one of (1) to (8) above, characterized in that the absorbing film has a thickness of 45 nm or less. (12) A reflective mask blank according to any one of (1) to (11) above, characterized in that it comprises a capping layer between the reflective layer and the absorbing layer. (13) A method for manufacturing a semiconductor device comprising: a substrate; a reflective layer formed on the substrate and reflecting EUV light; and a patterned absorbing layer formed on the reflective layer and absorbing EUV light, wherein the absorbing layer contains platinum (Pt) in the largest amount among elements constituting the absorbing layer, and contains at least one or more elements selected from a first material group other than the platinum (Pt), and the absorbing layer has a film density of 9.0 g / cm ３(14) The reflective mask according to (13) above, wherein the first material group consists of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), nickel (Ni), cobalt (Co), bismuth (Bi), iron (Fe), gold (Au), palladium (Pd), rhenium (Re), tin (Sn), oxygen (O), nitrogen (N), and boron (B). (15) The reflective mask according to (13) above, wherein the first material group consists of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), oxygen (O), nitrogen (N), and boron (B). (16) The reflective mask according to any one of (13) to (15) above, characterized in that the absorption layer contains platinum (Pt) at 51 atomic % or more of the metal elements contained in the absorption layer. (17) The reflective mask according to any one of (13) to (15) above, characterized in that the absorption layer contains platinum (Pt) at 60 atomic % or more of the metal elements contained in the absorption layer. (18) The reflective mask according to any one of (13) to (15) above, characterized in that the absorption layer contains platinum (Pt) at 70 atomic % or more of the metal elements contained in the absorption layer. (19) The reflective mask according to any one of (13) to (15) above, characterized in that the absorption layer has a film density of 9.5 g / cm ３ (20) The reflective mask according to any one of (13) to (18), wherein the absorption layer has a film density of 10.0 g / cm or more. ３(21) The reflective mask according to any one of (13) to (18) above, characterized in that the absorbing film has a thickness of less than 60 nm. (22) The reflective mask according to any one of (13) to (20) above, characterized in that the absorbing film has a thickness of 55 nm or less. (23) The reflective mask according to any one of (13) to (20) above, characterized in that the absorbing film has a thickness of 45 nm or less. (24) The reflective mask according to any one of (13) to (23) above, characterized in that a capping layer is included between the reflective layer and the absorbing layer. (25) A method for manufacturing a semiconductor device, comprising: forming a reflective layer that reflects EUV light on a substrate; and forming a patterned absorbing layer that absorbs EUV light on the reflective layer, wherein the absorbing layer contains platinum (Pt) in the largest amount among elements constituting the absorbing layer, and contains at least one or more elements selected from a first material group other than the platinum (Pt), and the absorbing layer has a film density of 9.0 g / cm ３(26) A method for manufacturing a reflective mask according to (25) above, wherein the first material group consists of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), nickel (Ni), cobalt (Co), bismuth (Bi), iron (Fe), gold (Au), palladium (Pd), rhenium (Re), tin (Sn), oxygen (O), nitrogen (N), and boron (B). (27) A method for manufacturing a reflective mask according to (25) above, wherein the first material group consists of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), oxygen (O), nitrogen (N), and boron (B). (28) The method for manufacturing a reflective mask according to any one of (25) to (27) above, characterized in that the absorption layer contains platinum (Pt) at 51 atomic % or more of the metal elements contained in the absorption layer. (29) The method for manufacturing a reflective mask according to any one of (25) to (27) above, characterized in that the absorption layer contains platinum (Pt) at 60 atomic % or more of the metal elements contained in the absorption layer. (30) The method for manufacturing a reflective mask according to any one of (25) to (27) above, characterized in that the absorption layer contains platinum (Pt) at 70 atomic % or more of the metal elements contained in the absorption layer. (31) The method for manufacturing a reflective mask according to any one of (25) to (27) above, characterized in that the absorption layer has a film density of 9.5 g / cm ３ (32) The method for manufacturing a reflective mask according to any one of (25) to (30), wherein the absorbing layer has a film density of 10.0 g / cm or more. ３(33) A method for manufacturing a reflective mask according to any one of (25) to (32) above, characterized in that the absorbing film has a thickness of less than 60 nm. (34) A method for manufacturing a reflective mask according to any one of (25) to (32) above, characterized in that the absorbing film has a thickness of 55 nm or less. (35) A method for manufacturing a reflective mask according to any one of (25) to (32) above, characterized in that the absorbing film has a thickness of 45 nm or less. (36) A method for manufacturing a reflective mask according to any one of (25) to (35) above, characterized in that a capping layer is included between the reflective layer and the absorbing layer.

[0103] The reflective photomask according to the present invention can be suitably used to form a fine pattern by EUV exposure in the manufacturing process of semiconductor integrated circuits and the like.

[0104] REFERENCE SIGNS LIST 1... Substrate 2... Reflective layer 3... Protective layer (capping layer) 4... Absorbing layer 5... Reflective portion 10... Reflective photomask blank (reflective mask blank) 20... Reflective photomask (reflective mask)

Claims

1. A method for manufacturing a semiconductor device comprising: a substrate; a reflective layer formed on the substrate and reflecting EUV light; and an absorbing layer formed on the reflective layer and absorbing EUV light, the absorbing layer containing platinum (Pt) in the largest amount of all elements constituting the absorbing layer, and containing at least one or more elements selected from a first material group other than the platinum (Pt), the absorbing layer having a film density of 9.0 g / cm ３ The reflective mask blank is as described above.

2. The reflective mask blank according to claim 1, wherein the first material group is composed of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), nickel (Ni), cobalt (Co), bismuth (Bi), iron (Fe), gold (Au), palladium (Pd), rhenium (Re), tin (Sn), oxygen (O), nitrogen (N), and boron (B).

3. The reflective mask blank according to claim 1, wherein the first material group is composed of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), oxygen (O), nitrogen (N), and boron (B).

4. A reflective mask blank according to claim 3, wherein the absorption layer contains 51 atomic % or more of platinum (Pt) among the metal elements contained in the absorption layer.

5. A reflective mask blank according to claim 3, wherein the absorption layer contains 60 atomic % or more of platinum (Pt) among the metal elements contained in the absorption layer.

6. A reflective mask blank according to claim 3, wherein the absorption layer contains 70 atomic % or more of platinum (Pt) among the metal elements contained in the absorption layer.

7. The absorbing layer has a film density of 9.5 g / cm ３ The reflective mask blank according to claim 6 .

8. The absorbing layer has a film density of 10.0 g / cm ３ The reflective mask blank according to claim 6 .

9. The reflective mask blank according to claim 8, wherein the absorbing film has a thickness of less than 60 nm.

10. The reflective mask blank according to claim 8, wherein the absorbing film has a thickness of 55 nm or less.

11. The reflective mask blank according to claim 8, wherein the absorbing film has a thickness of 45 nm or less.

12. A reflective mask blank according to any one of claims 1 to 11, comprising a capping layer between the reflective layer and the absorbing layer.

13. A method for manufacturing a semiconductor device comprising: a substrate; a reflective layer formed on the substrate and reflecting EUV light; and a patterned absorbing layer formed on the reflective layer and absorbing EUV light, the absorbing layer containing platinum (Pt) in the largest amount among elements constituting the absorbing layer, and containing at least one or more elements selected from a first material group other than the platinum (Pt), the absorbing layer having a film density of 9.0 g / cm ３ That's all about the reflective mask.

14. The reflective mask of claim 13, wherein the first group of materials consists of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), nickel (Ni), cobalt (Co), bismuth (Bi), iron (Fe), gold (Au), palladium (Pd), rhenium (Re), tin (Sn), oxygen (O), nitrogen (N), and boron (B).

15. The reflective mask of claim 13, wherein the first group of materials consists of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), oxygen (O), nitrogen (N), and boron (B).

16. The reflective mask according to claim 15, wherein said absorbing layer contains platinum (Pt) in an amount of 51 atomic % or more among the metal elements contained in said absorbing layer.

17. The reflective mask according to claim 15, wherein said absorbing layer contains platinum (Pt) in an amount of 60 atomic % or more among the metal elements contained in said absorbing layer.

18. The reflective mask according to claim 15, wherein the absorption layer contains 70 atomic % or more of platinum (Pt) among the metal elements contained in the absorption layer.

19. The absorbing layer has a film density of 9.5 g / cm ３ 20. The reflective mask according to claim 18, wherein said reflective mask is 20. The absorbent layer has a film density of 10.0 g / cm ３ 20. The reflective mask according to claim 18, wherein said reflective mask is 21. The reflective mask according to claim 20, wherein the absorbing film has a thickness of less than 60 nm.

22. The reflective mask according to claim 20, wherein the absorbing film has a thickness of 55 nm or less.

23. The reflective mask according to claim 20, wherein the absorbing film has a thickness of 45 nm or less.

24. The reflective mask of any one of claims 13 to 23, further comprising a capping layer between the reflective layer and the absorbing layer.

25. A method for manufacturing a semiconductor device comprising the steps of: forming a reflective layer that reflects EUV light on a substrate; and forming a patterned absorbing layer that absorbs EUV light on the reflective layer, wherein the absorbing layer contains platinum (Pt) in the largest amount among elements constituting the absorbing layer, and contains at least one or more elements selected from a first material group other than the platinum (Pt), and the absorbing layer has a film density of 9.0 g / cm. ３ This is the above method for manufacturing a reflective mask.

26. The method for manufacturing a reflective mask according to claim 25, wherein the first group of materials is composed of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), nickel (Ni), cobalt (Co), bismuth (Bi), iron (Fe), gold (Au), palladium (Pd), rhenium (Re), tin (Sn), oxygen (O), nitrogen (N), and boron (B).

27. The method for manufacturing a reflective mask according to claim 25, wherein the first material group is composed of the elements niobium (Nb), ruthenium (Ru), iridium (Ir), tantalum (Ta), titanium (Ti), chromium (Cr), indium (In), oxygen (O), nitrogen (N), and boron (B).

28. The method for producing a reflective mask according to claim 27, wherein the absorption layer contains platinum (Pt) in an amount of 51 atomic % or more among the metal elements contained in the absorption layer.

29. The method for manufacturing a reflective mask according to claim 27, wherein the absorption layer contains platinum (Pt) in an amount of 60 atomic % or more among the metal elements contained in the absorption layer.

30. The method for manufacturing a reflective mask according to claim 27, wherein the absorption layer contains 70 atomic % or more of platinum (Pt) among the metal elements contained in the absorption layer.

31. The absorbent layer has a film density of 9.5 g / cm ３ The method for producing a reflective mask according to claim 30, 32. The absorbent layer has a film density of 10.0 g / cm ３ The method for producing a reflective mask according to claim 30, 33. The method for producing a reflective mask according to claim 32, wherein the absorbing film has a thickness of less than 60 nm.

34. The method for producing a reflective mask according to claim 32, wherein the absorbing film has a thickness of 55 nm or less.

35. The method for producing a reflective mask according to claim 32, wherein the absorbing film has a thickness of 45 nm or less.

36. A method for manufacturing a reflective mask according to any one of claims 25 to 35, further comprising a capping layer between the reflective layer and the absorbing layer.

Images