Photomask blank and photomask

Abstract

The present application provides a photomask blank, which has a transparent substrate, and a light shielding film containing a chromium-based material arranged on one surface of the transparent substrate, the light shielding film having a sheet resistance of 10 3 Ω / □ or more and 10 7 Ω / □ or less.

Description

TECHNICAL FIELD

[0001] The present application relates to a photomask blank and a photomask. BACKGROUND

[0002] The photolithography technique is widely used in the manufacture of semiconductor devices, display devices, and the like. For a photomask used in photolithography, electrostatic breakdown (also referred to as discharge breakdown) becomes a problem.

[0003] As a countermeasure against electrostatic breakdown, a method of forming a conductive layer between a transparent substrate and a light-shielding pattern in a photomask having the light-shielding pattern on the transparent substrate is proposed. In this method, the potential difference between adjacent light-shielding patterns is reduced by the conductive layer, and thus electrostatic breakdown can be suppressed. For example, Patent Literature 1 discloses a photomask blank including a light-transmissive substrate, an amorphous silicon film formed on the light-transmissive substrate, a conductive layer composed of a metal silicide formed on the amorphous silicon film, and a light-shielding metal layer formed on the conductive layer. In addition, Patent Literature 2 discloses a substrate for a photomask having a glass substrate, and in the glass substrate, an impurity-containing layer containing an alkali metal and having conductivity is formed from a film formation surface on which a light-shielding film is formed up to a prescribed depth in the thickness direction of the glass substrate.

[0004] In addition, Patent Literature 3 proposes a photomask in which a pattern portion is formed on one surface of a transparent substrate by a plurality of pattern patterns composed of a light-shielding film having light-shielding properties with respect to exposure light at the time of transfer, and at a portion where two adjacent pattern patterns are close to each other, a connection line portion electrically connecting the two pattern patterns is provided, which is composed of a first half-tone film having semi-transmissive properties with respect to exposure light at the time of transfer and has a line width that does not substantially develop at the time of transfer, in order to prevent discharge breakdown of the two pattern patterns at the portion where the two pattern patterns are close to each other due to discharge. In this method, the potential difference between adjacent light-shielding patterns is reduced by the connection line portion, and thus electrostatic breakdown can be suppressed.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Laid-Open No. 61-11749

[0008] Patent Literature 2: Japanese Patent Application Laid-Open No. 2014-21431

[0009] Patent Literature 3: Japanese Patent Application Laid-Open No. 2009-122295 SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] However, in the case where a conductive layer, a connection line portion is formed in a photomask, for example, as described in Patent Documents 1 to 3, the manufacturing process of the photomask can become complicated and high cost.

[0012] The present application was accomplished in view of the above-described circumstances, and a main object thereof is to provide a photomask blank and a photomask capable of suppressing electrostatic breakdown.

[0013] Means for solving the problem

[0014] To solve the above-described problem, the present application provides a photomask blank having a transparent substrate, and a light-shielding film containing a chromium-based material disposed on one surface of the transparent substrate, a sheet resistance of the light-shielding film being 10 3 Ω / □ or more and 10 7 Ω / □ or less.

[0015] In the photomask blank of the present application, it is preferable that the light-shielding film have, in order from the transparent substrate side, a light-shielding layer and a low-reflection layer.

[0016] In the photomask blank of the present application, it is preferable that the thickness of the light-shielding layer be 100 nm or more and 200 nm or less.

[0017] In the photomask blank of the present application, it is preferable that the light-shielding layer contain the chromium-based material containing oxygen.

[0018] In the photomask blank of the present application, it is preferable that the thickness of the light-shielding film be 140 nm or more and 280 nm or less.

[0019] Further, in the present application, a photomask having a transparent substrate, and a light-shielding pattern containing a chromium-based material disposed on one surface of the transparent substrate, a sheet resistance of the light-shielding pattern being 10 3 Ω / □ or more and 10 7 Ω / □ or less.

[0020] In the photomask of the present application, it is preferable that the light-shielding pattern have, in order from the transparent substrate side, a light-shielding layer and a low-reflection layer.

[0021] In the photomask of the present application, it is preferable that the thickness of the light-shielding layer be 100 nm or more and 200 nm or less.

[0022] In the photomask of the present application, it is preferable that the light-shielding layer contain the chromium-based material containing oxygen.

[0023] In the photomask of the present application, it is preferable that the thickness of the light-shielding pattern be 140 nm or more and 280 nm or less.

[0024] Effects of the Invention

[0025] The present invention can provide a photomask blank and a photomask capable of suppressing electrostatic damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] [ Figure 1 ] is a schematic cross-sectional view illustrating a photomask blank of the present invention.

[0027] [ Figure 2 ] is a schematic cross-sectional view illustrating a photomask blank of the present invention.

[0028] [ Figure 3 ] is a schematic cross-sectional view illustrating a photomask of the present invention.

[0029] [ Figure 4 ] is a schematic cross-sectional view illustrating a photomask of the present invention.

[0030] [ Figure 5 ] is a schematic plan view showing the photomasks of the embodiment and the comparative example. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings and the like. However, the present invention can be implemented in many different ways and is not to be construed as being limited to the description of the embodiments illustrated below. In addition, in order to make the description clearer, the drawings sometimes schematically indicate the width, thickness, shape, etc. of each part compared to the actual manner, but this is only an example and does not limit the interpretation of the present invention. In addition, in this specification and the drawings, for elements that are the same as those described with respect to the drawings that have already appeared, the same symbols are sometimes given and detailed descriptions are appropriately omitted.

[0032] In this specification, when expressing a manner of arranging another member on a certain member, when simply described as "above" or "below", unless otherwise specified, it is assumed that both the case where the other member is arranged directly above or directly below the certain member in a manner of contacting the certain member and the case where the other member is arranged above or below the certain member with another member interposed therebetween are included. In addition, in this specification, when expressing a manner of arranging another member on the surface of a certain member, when simply described as "surface", unless otherwise specified, it is assumed that both the case where the other member is arranged directly above or directly below the certain member in a manner of contacting the certain member and the case where the other member is arranged above or below the certain member with another member interposed therebetween are included.

[0033] Hereinafter, the photomask blank and the photomask of the present invention will be described in detail.

[0034] A. Photomask Blanks

[0035] The photomask blank of the present application is a photomask blank having a transparent substrate, and a light-blocking film containing a chromium-based material disposed on one face of the transparent substrate, the sheet resistance of the light-blocking film being 10 3 Ω / □ or more and 10 7 Ω / □ or less.

[0036] Figure 1 is a schematic cross-sectional view illustrating the photomask blank of the present application. As shown in Figure 1 , the photomask blank 1 has a transparent substrate 2, and a light-blocking film 3 containing a chromium-based material disposed on one face of the transparent substrate 2. The sheet resistance of the light-blocking film 3 is within a prescribed range. In the example shown in Figure 1 , the light-blocking film 3 has, in order from the transparent substrate 2 side, a light-blocking layer 3a and a low-reflection layer 3b, but is not limited thereto.

[0037] Here, the sheet resistance indicates the resistance of a thin film, and for example, if the sheet resistance of the light-blocking film is high, it can be said that the resistance of the light-blocking film is high.

[0038] According to the present application, the sheet resistance of the light-blocking film is high to within the above range, and thus in the case where a photomask having a light-blocking pattern on one face of a transparent substrate is manufactured using the photomask blank of the present application, when static electricity carried in the photomask is discharged, the current flowing through the light-blocking pattern can be reduced. Then, the heat generated by the discharge current can be reduced. As a result, static electricity damage can be suppressed.

[0039] Further, according to the present application, the sheet resistance of the light-blocking film can be adjusted by, for example, adjusting the composition of the light-blocking film containing a chromium-based material, and thus a photomask can be manufactured using the photomask blank of the present application by a simple process without requiring a complicated process.

[0040] Hereinafter, each of the components in the photomask blank of the present application will be described.

[0041] 1. Light-blocking film

[0042] The light-blocking film of the present application is a member disposed on one face of a transparent substrate, and containing a chromium-based material, the sheet resistance of which is within a prescribed range.

[0043] The sheet resistance of the light-blocking film is 10 3 Ω / □ or more, and preferably 10 5 Ω / □ or more. Further, the sheet resistance of the light-blocking film is 10 7 Ω / □ or less. The sheet resistance of the light-blocking film is 10 3 Ω / □ or more and 10 7 Ω / □ or less, and preferably 10 5 Ω / □ or more and 10 7The sheet resistance of the light-blocking film described above is preferably 1.0 Ω / □ or less. By having the sheet resistance of the light-blocking film described above be within the range described above, electrostatic breakdown can be suppressed. In addition, for example, when the light-blocking film has a low-reflection layer or region having a relatively high sheet resistance among the layers that make up the light-blocking film, the thicker the thickness of such a low-reflection layer or region having a relatively high sheet resistance, the more the sheet resistance of the light-blocking film tends to increase, but if the thickness of the low-reflection layer or region is too thick, the etching rate slows down, and the plate-making properties of the light-blocking film can decrease. Therefore, by having the sheet resistance of the light-blocking film described above be 1.0 Ω / □ or less, good plate-making properties can be obtained.

[0044] Here, the sheet resistance described above is a value determined by the four-terminal four-probe method. The resistivity meter can use, for example, a low-resistivity meter Loresta-GX MCP-T700 manufactured by Mitsubishi Chemical Corporation, and as the four-probe probe, for example, an ASP probe manufactured by Mitsubishi Chemical Corporation can be used. Note that the sheet resistance is determined 10 times, and the average value is set as the value of the sheet resistance.

[0045] As a means for setting the sheet resistance of the light-blocking film described above to be within a prescribed range, for example, a method in which the light-blocking film described above contains an element that can be a factor that hinders the movement of free electrons can be given. As the element, oxygen is preferable. That is, the light-blocking film described above preferably contains a chromium-based material that contains oxygen.

[0046] The optical density of the light-blocking film described above with respect to exposure light is preferably 3.0 or more. Specifically, the optical density of the light-blocking film described above with respect to light having a wavelength of 200 nm or more and 450 nm or less is preferably 3.0 or more. This is because, if the optical density of the light-blocking film described above is within the range described above, the light-blocking film described above can have the desired light-blocking properties. Note that the optical density described above can be determined using a spectrophotometer.

[0047] In addition, as the thickness of the light-blocking film described above, there is no particular limitation as long as a light-blocking film having the sheet resistance and optical density described above can be made, and for example, it can be set to 140 nm or more, of which 150 nm or more is preferable, and 170 nm or more is particularly preferable. In addition, the thickness of the light-blocking film described above can be set to 280 nm or less, of which 270 nm or less is preferable, and 240 nm or less is particularly preferable. The thickness of the light-blocking film described above can be set to 140 nm or more and 280 nm or less, of which 150 nm or more and 270 nm or less is preferable, and 170 nm or more and 240 nm or less is particularly preferable. This is because, if the thickness of the light-blocking film described above is within the range described above, the light-blocking film described above can have the desired light-blocking properties. Note that in the case where the light-blocking film described above has a plurality of layers, the thickness described above is the thickness of the entire light-blocking film.

[0048] The light shielding film described above contains a chromium-based material and has a sheet resistance within the range described above, and for example, the light shielding film can have a plurality of layers, or can be a film whose composition changes in the thickness direction. Hereinafter, the case where the light shielding film has a plurality of layers (first embodiment) and the case where the light shielding film is a film whose composition changes in the thickness direction (second embodiment) are described.

[0049] (1) First embodiment of the light shielding film

[0050] The light shielding film of the present embodiment contains a chromium-based material, has a sheet resistance within a prescribed range, and has a plurality of layers.

[0051] The light shielding film described above contains a chromium-based material, has a sheet resistance within a prescribed range, and has a plurality of layers, and the light shielding film preferably has, from the transparent substrate side, a light shielding layer and a low reflection layer in this order. For example, in Figure 1 , the light shielding film 3 has, from the transparent substrate 2 side, a light shielding layer 3a and a low reflection layer 3b in this order. With the low reflection layer, reflection of exposure light can be prevented, and therefore, a more clear pattern can be formed with a photomask manufactured using the photomask blank of the present application. In addition, the low reflection layer contains, for example, a chromium-based material containing oxygen, nitrogen, or carbon, and therefore, can have an antireflection function, and particularly in the case where a chromium-based material containing oxygen is contained, the antireflection function can be improved. Here, in the case where the low reflection layer contains a chromium-based material containing oxygen, as described above, the sheet resistance of the entire light shielding film can be increased to within the prescribed range. Therefore, by having the light shielding film have, from the transparent substrate side, a light shielding layer and a low reflection layer in this order, the sheet resistance of the entire light shielding film can be increased to within the prescribed range.

[0052] In addition, the light shielding film described above can have a low reflection layer between the transparent substrate and the light shielding layer. That is, for example, as shown in Figure 2 , the light shielding film 3 can have, from the transparent substrate 2 side, a second low reflection layer 3c, a light shielding layer 3a, and a first low reflection layer 3b in this order. With the first low reflection layer and the second low reflection layer, reflection of exposure light can be prevented, and therefore, a more clear pattern can be formed with a photomask manufactured using the photomask blank of the present application. In addition, the first low reflection layer and the second low reflection layer contain, for example, a chromium-based material containing oxygen, nitrogen, or carbon, and therefore, can have an antireflection function, and particularly in the case where a chromium-based material containing oxygen is contained, the antireflection function can be improved. Here, in the case where the first low reflection layer and the second low reflection layer contain a chromium-based material containing oxygen, as described above, the sheet resistance of the entire light shielding film can be increased to within the prescribed range. Therefore, by having the light shielding film have, from the transparent substrate side, a second low reflection layer, a light shielding layer, and a first low reflection layer in this order, the sheet resistance of the entire light shielding film can be increased to within the prescribed range.

[0053] Note that in this specification, a low reflection layer disposed on the side of the light-blocking layer opposite the transparent substrate is referred to as a first low reflection layer, and a low reflection layer disposed on the side of the light-blocking layer close to the transparent substrate is referred to as a second low reflection layer.

[0054] Next, the layers constituting the light-blocking film of this embodiment are described.

[0055] (a) Light-blocking layer

[0056] The light-blocking layer constituting the light-blocking film of this embodiment is a layer containing a chromium-based material. The light-blocking layer can be provided as a layer having the highest light-blocking property among the layers constituting the light-blocking film described above.

[0057] As the chromium-based material contained in the light-blocking layer described above, a chromium-based material used in a general photomask blank can be used, and a chromium compound is preferable. Here, as described above, by using a chromium-based material containing oxygen in the low reflection layer, the sheet resistance of the light-blocking film as a whole can be increased, but if the resistance of the light-blocking layer is extremely low compared to the resistance of the low reflection layer, it is possible that current will selectively flow through the light-blocking layer and cause electrostatic breakdown. Therefore, the chromium-based material contained in the light-blocking layer is preferably a chromium compound, rather than metallic chromium. As the chromium-based material described above, for example, a chromium-based material containing at least one of oxygen, nitrogen, and carbon, such as chromium oxide, chromium oxynitride, chromium oxycarbonitride, chromium oxycarbide, chromium nitride, and chromium carbide, can be given.

[0058] The chromium-based material contained in the light-blocking layer described above is preferably a chromium-based material containing oxygen. This is because, by containing oxygen in the light-blocking layer, the sheet resistance of the light-blocking film as a whole can be increased to a prescribed range. As the chromium-based material containing oxygen, for example, chromium oxide, chromium oxynitride, chromium oxycarbonitride, and chromium oxycarbide can be given.

[0059] In the case where the light-blocking layer described above contains a chromium-based material containing oxygen, the proportion of oxygen atoms contained in the light-blocking layer described above is not particularly limited as long as a light-blocking film having a desired sheet resistance and optical density can be obtained, and for example, it is preferably 5 atomic% or more, and more preferably 7 atomic% or more. In addition, the proportion of oxygen atoms contained in the light-blocking layer described above can be, for example, 20 atomic% or less. The proportion of oxygen atoms contained in the light-blocking layer described above is preferably, for example, 5 atomic% or more and 20 atomic% or less, and more preferably 7 atomic% or more and 20 atomic% or less. By the proportion of oxygen atoms contained in the light-blocking layer described above being within the range described above, both a high sheet resistance and a high light-blocking property of the light-blocking film as a whole can be achieved.

[0060] Here, the proportion of oxygen atoms contained in the light-blocking layer described above can be measured, for example, by X-ray photoelectron spectroscopy (XPS). As an X-ray photoelectron spectroscopy device, for example, Quantum 2000 manufactured by ULVAC-PHI, Inc. can be used. The specific measurement conditions are as follows.

[0061] • Incident X-ray: Monochromated Al Kα line

[0062] • X-ray irradiation area (measurement area): 200 μmφ

[0063] • X-ray output power: 30 W

[0064] • Photoelectron take-off angle: 45°

[0065] • Charging neutralization condition: Electron neutralizer gun (0.02 mA), low acceleration Ar+ ion irradiation

[0066] • Measurement peaks: Cr2p, Si2p, C1s, N1s, O1s

[0067] • Quantification: The background was obtained by the Shirley method, and the atomic ratio was calculated from the peak area obtained using the relative sensitivity coefficient method.

[0068] As the thickness of the light-blocking layer, there is no particular limitation as long as a light-blocking film having the above-described sheet resistance and optical density can be obtained, and for example, it is preferably 100 nm or more and 200 nm or less. By the thickness of the light-blocking layer being within the above-described range, the film strength of the light-blocking layer can be improved, and the occurrence of electrostatic breakdown can be suppressed, and the resistance to heat generated by a discharge current can be improved. In addition, if the thickness is too thin, sufficient light-blocking properties are not sometimes obtained, and if the thickness is too thick, it is sometimes difficult to process a light-blocking pattern with good precision when a photomask is manufactured using the photomask blank of the present application.

[0069] As the method of forming the light-blocking layer, for example, sputtering, vacuum evaporation, ion plating, and the like can be given. More specifically, for example, the following method can be given: a Cr target is installed in a vacuum chamber, O2, N2, CO2 gas, or the like is introduced, and film formation is performed by reactive sputtering in a vacuum environment. In this method, by adjusting the ratio of O2 gas, the proportion of oxygen atoms contained in the light-blocking layer can be adjusted. Thereby, the sheet resistance and optical density of the light-blocking film as a whole can be adjusted.

[0070] (b) First low-reflection layer

[0071] The first low-reflection layer constituting the light-blocking film of the present embodiment is a layer containing a chromium-based material, which is disposed on the side of the light-blocking layer opposite to the transparent substrate.

[0072] As the chromium-based material contained in the first low-reflection layer, a chromium-based material used in a general photomask blank can be used. As the chromium-based material, for example, chromium oxide, chromium oxynitride, chromium oxycarbonitride, chromium oxycarbide, chromium nitride, chromium carbide, or the like containing at least one of oxygen, nitrogen, and carbon can be given.

[0073] In the first low-reflection layer, the chromium-based material preferably contains oxygen. This is because the sheet resistance of the light-blocking film as a whole can be increased to a predetermined range by including oxygen in the first low-reflection layer. Examples of the chromium-based material containing oxygen include chromium oxide, chromium nitride oxide, chromium carbonitride oxide, and chromium oxycarbide.

[0074] In the case where the first low-reflection layer and the light-blocking layer contain a chromium-based material containing oxygen, the proportion of oxygen atoms in the first low-reflection layer is preferably higher than the proportion of oxygen atoms in the light-blocking layer. This is because, as described above, the light-blocking layer preferably has the highest light-blocking property among the layers constituting the light-blocking film.

[0075] The proportion of oxygen atoms in the first low-reflection layer is not particularly limited as long as it is higher than the proportion of oxygen atoms in the light-blocking layer and a light-blocking film having a desired sheet resistance and optical density can be obtained, and is appropriately adjusted depending on the target sheet resistance, optical density, antireflection function, chemical resistance, adhesion to a resist, and the like.

[0076] In the case where the first low-reflection layer contains at least a chromium-based material containing carbon, the proportion of carbon atoms in the first low-reflection layer is not particularly limited as long as a light-blocking film having a desired sheet resistance and optical density can be obtained, and is preferably, for example, 5 atomic% or less, more preferably 3 atomic% or less, and further preferably 2 atomic% or less. If the proportion of carbon atoms in the first low-reflection layer is too high, the etching rate will be slow in the case where the light-blocking film is patterned by wet etching, and the plate-making properties of the first low-reflection layer can be reduced. In this regard, in the case of a photomask blank and a photomask, the mother glass, the display device, and the like are becoming larger, and in the case of a large photomask blank and a large photomask, the thickness of the light-blocking film tends to be thick. Therefore, particularly in the case of a large photomask blank, the proportion of carbon atoms in the first low-reflection layer is preferably small so as to be within the above range from the viewpoint of plate-making properties. Note that the lower limit of the proportion of carbon atoms in the first low-reflection layer is not particularly limited.

[0077] In the case where the first low-reflection layer contains at least a chromium-based material containing nitrogen, the proportion of nitrogen atoms in the first low-reflection layer is not particularly limited as long as a light-blocking film having a desired sheet resistance and optical density can be obtained, and is preferably, for example, 10 atomic% or less, more preferably 9.5 atomic% or less, and further preferably 9.0 atomic% or less. By the proportion of nitrogen atoms in the first low-reflection layer being within the above range, the adhesion to a resist can be ensured. Note that the lower limit of the proportion of nitrogen atoms in the first low-reflection layer is not particularly limited.

[0078] Further, in the case where the first low-reflection layer contains the chromium-based material containing oxygen, nitrogen, and carbon, the content ratio of oxygen atoms, the content ratio of nitrogen atoms, and the content ratio of carbon atoms in the first low-reflection layer are preferably in the above ranges, respectively.

[0079] Here, the measurement method of the content ratio of oxygen atoms, the content ratio of carbon atoms, and the content ratio of nitrogen atoms in the first low-reflection layer can be the same as the measurement method of the content ratio of oxygen atoms in the light-shielding layer.

[0080] As the thickness of the first low-reflection layer, there is no particular limitation as long as the antireflection function can be exhibited and a light-shielding film having a desired sheet resistance and optical density can be obtained, and can be set to 20 nm or more and 40 nm or less, for example. If the thickness is too thin, the antireflection function can not be sufficiently obtained at times. Further, if the thickness is too thick, it can be difficult to process a light-shielding pattern with good precision when a photomask is manufactured using the photomask blank of the present application. Further, the first low-reflection layer is a layer having a higher sheet resistance among the layers constituting the light-shielding film, and the thicker the thickness of the first low-reflection layer, the more the sheet resistance of the light-shielding film tends to increase, but if the thickness of the first low-reflection layer is too thick, the etching rate becomes slow, and the plate-making properties of the first low-reflection layer can be reduced.

[0081] As the formation method of the low-reflection layer, the same as the formation method of the light-shielding layer can be set.

[0082] (c) Second Low-Reflection Layer

[0083] The second low-reflection layer constituting the light-shielding film of the present embodiment is a layer containing a chromium-based material, which is disposed on the side of the transparent substrate of the light-shielding layer.

[0084] Note that, as the chromium-based material contained in the second low-reflection layer, the content ratio of oxygen atoms in the second low-reflection layer, the thickness of the second low-reflection layer, and the formation method of the second low-reflection layer, the same as the first low-reflection layer can be set.

[0085] (2) Second Embodiment of Light-Shielding Film

[0086] The light-shielding film of the present embodiment is a film containing a chromium-based material, having a sheet resistance in a prescribed range, and having a composition that varies in the thickness direction.

[0087] Note that, the fact that the above light-shielding film is a film having a composition that varies in the thickness direction can be confirmed by, for example, performing elemental analysis in the depth direction (thickness direction) by combining ion etching in the depth direction (thickness direction) with X-ray photoelectron spectroscopy (XPS). The X-ray photoelectron spectroscopy device and the measurement conditions are as described above.

[0088] As the chromium-based material contained in the light-shielding film described above, a chromium-based material used in a general photomask blank can be used. Among them, the chromium-based material contained in the light-shielding film described above is preferably an oxygen-containing chromium-based material. This is because, by causing the light-shielding film to contain oxygen, it is possible to increase the sheet resistance of the light-shielding film to within a prescribed range. As the oxygen-containing chromium-based material, for example, chromium oxide, chromium oxynitride, chromium oxycarbonitride, chromium oxycarbide, and the like can be given.

[0089] In the case where the light-shielding film described above contains an oxygen-containing chromium-based material, the light-shielding film preferably has a concentration gradient in which the proportion of oxygen atoms contained varies in the thickness direction. In this case, for example, the light-shielding film can have a concentration gradient in which the proportion of oxygen atoms contained increases from the surface of the transparent substrate side toward the surface on the side opposite the transparent substrate (hereinafter, referred to as the first mode.), or can also have a concentration gradient in which the proportion of oxygen atoms contained increases from the inside toward the surface of the transparent substrate side and the proportion of oxygen atoms contained increases from the inside toward the surface on the side opposite the transparent substrate (hereinafter, referred to as the second mode.).

[0090] In the first mode, the light-shielding film has a concentration gradient in which the proportion of atoms contained increases from the surface of the transparent substrate side toward the surface on the side opposite the transparent substrate. That is, the light-shielding film can have a concentration gradient in which the proportion of oxygen atoms contained is small on the surface of the transparent substrate side and the proportion of oxygen atoms contained is large on the surface on the side opposite the transparent substrate. In this case, it is possible to impart an antireflection function to the surface on the side opposite the transparent substrate of the light-shielding film. In addition, by the light-shielding film having the concentration gradient described above, it is possible to increase the sheet resistance of the light-shielding film as a whole to within a prescribed range.

[0091] In the case of the first mode described above, as for the proportion of oxygen atoms contained on the surface of the transparent substrate side of the light-shielding film, it is sufficient that it be less than the proportion of oxygen atoms contained on the surface on the side opposite the transparent substrate of the light-shielding film, and there is no particular limitation as long as a light-shielding film having a desired sheet resistance and optical density can be obtained, and for example, it is preferably 5 atomic% or more, and more preferably 7 atomic% or more. In addition, the proportion of oxygen atoms contained on the surface of the transparent substrate side of the light-shielding film described above can be, for example, 20 atomic% or less. The proportion of oxygen atoms contained on the surface of the transparent substrate side of the light-shielding film described above is, for example, preferably 5 atomic% or more and 20 atomic% or less, and more preferably 7 atomic% or more and 20 atomic% or less. By the proportion of oxygen atoms contained on the surface of the transparent substrate side of the light-shielding film being within the range described above, it is possible to achieve both a high sheet resistance and a high light-shielding property of the light-shielding film as a whole.

[0092] Further, in the case of the above-described first mode, the thickness of the region in which the proportion of oxygen atoms contained in the surface on the transparent substrate side of the light-shielding film is 5 atomic % or more is preferably, for example, 100 nm or more and 200 nm or less. That is, it is preferable that the light-shielding film have a region in which the proportion of oxygen atoms contained is within a prescribed range in the thickness direction from the surface on the transparent substrate side, with a prescribed thickness. By having the thickness of the above-described region within the above-described range, it is possible to improve the film strength of the light-shielding film, to make it less likely to be damaged by static electricity, and to improve the resistance to heat generated by a discharge current. Further, if the thickness of the above-described region is too thin, sufficient light-shielding properties can not be obtained, and if the thickness of the above-described region is too thick, it can be difficult to process the light-shielding pattern with good precision when a photomask is manufactured using the photomask blank of the present application.

[0093] Further, in the case of the above-described first mode, the proportion of oxygen atoms contained in the surface on the side opposite the transparent substrate of the light-shielding film can be more than the proportion of oxygen atoms contained in the surface on the transparent substrate side of the light-shielding film, and is not particularly limited as long as a light-shielding film having a desired sheet resistance and optical density can be obtained, and can be appropriately adjusted according to the target sheet resistance and optical density, etc.

[0094] In the second mode, the light-shielding film has a concentration gradient in which the proportion of oxygen atoms contained increases from the inside toward the surface on the transparent substrate side, and the proportion of oxygen atoms contained increases from the inside toward the surface on the side opposite the transparent substrate. That is, the light-shielding film can have a concentration gradient in which the proportion of oxygen atoms contained is small in the inside, and the proportion of oxygen atoms contained is large in the surface on the transparent substrate side and in the surface on the side opposite the transparent substrate. In this case, it is possible to impart an antireflection function to the surface on the transparent substrate side of the light-shielding film, and to the surface on the side opposite the transparent substrate of the light-shielding film. Further, by the light-shielding film having the above-described concentration gradient, it is possible to increase the sheet resistance of the entire light-shielding film to within a prescribed range.

[0095] In the case of the above-described second mode, the proportion of oxygen atoms contained in the inside of the light-shielding film can be less than the proportion of oxygen atoms contained in the surface on the transparent substrate side of the light-shielding film and the proportion of oxygen atoms contained in the surface on the side opposite the transparent substrate of the light-shielding film, and is not particularly limited as long as a light-shielding film having a desired sheet resistance and optical density can be obtained, and is preferably, for example, 5 atomic % or more, more preferably 7 atomic % or more. Further, the proportion of oxygen atoms contained in the inside of the above-described light-shielding film can be, for example, 20 atomic % or less. The proportion of oxygen atoms contained in the inside of the above-described light-shielding film is preferably, for example, 5 atomic % or more and 20 atomic % or less, more preferably 7 atomic % or more and 20 atomic % or less. By the proportion of oxygen atoms contained in the inside of the above-described light-shielding film being within the above-described range, it is possible to balance a high sheet resistance of the entire light-shielding film and high light-shielding properties.

[0096] Further, in the case of the above-described second method, the thickness of the region in which the proportion of oxygen atoms is 5 atomic % or more is, for example, preferably 100 nm or more and 200 nm or less. That is, it is preferable that the light shielding film have, inside, a region in which the proportion of oxygen atoms is within a prescribed range, with a prescribed thickness. By having the thickness of the above-described region within the above-described range, it is possible to improve the film strength of the light shielding film, to make it less likely to be damaged by static electricity, and to improve the resistance to heat generated by discharge current. Further, if the thickness of the above-described region is too thin, it is sometimes not possible to obtain sufficient light shielding properties, and if the thickness of the above-described region is too thick, it is sometimes difficult to process the light shielding pattern with good precision when manufacturing a photomask using the photomask blank of the present application.

[0097] Further, in the case of the above-described second method, the proportion of oxygen atoms on the surface of the light shielding film on the transparent substrate side and the proportion of oxygen atoms on the surface of the light shielding film on the side opposite the transparent substrate can be more than the proportion of oxygen atoms inside the light shielding film, and are not particularly limited as long as a light shielding film having a desired sheet resistance and optical density can be obtained, and can be appropriately adjusted according to the target sheet resistance and optical density, etc.

[0098] Note that the proportion of oxygen atoms in the thickness direction of the above-described light shielding film can be measured by, for example, combining ion etching in the depth direction (thickness direction) with X-ray photoelectron spectroscopy (XPS) to perform elemental analysis in the depth direction (thickness direction). The X-ray photoelectron spectroscopy device and measurement conditions are as described above.

[0099] As the method of forming the above-described light shielding film, there are no particular limitations as long as it is a method that enables the composition to vary in the thickness direction, and examples include sputtering methods, etc. More specifically, examples include methods in which a Cr target is installed in a vacuum chamber, O2, N2, CO2 gas, etc. is introduced, and film formation is performed by reactive sputtering in a vacuum environment. In this method, by adjusting the ratio of O2 gas, it is possible to adjust the proportion of oxygen atoms in the above-described light shielding layer. Thereby, it is possible to adjust the sheet resistance and optical density of the light shielding film as a whole.

[0100] 2. Transparent substrate

[0101] The transparent substrate of the present application is a member that supports the above-described light shielding film, and has light transmittance.

[0102] As the above-described transparent substrate, a transparent substrate used in general photomasks can be used. As the above-described transparent substrate, for example, a transparent substrate that has been optically ground can be used, and specifically, examples include soda lime glass, aluminoborosilicate glass, borosilicate glass, synthetic quartz, fluorite, calcium fluoride, etc. Among these, it is preferable to use synthetic quartz. This is because the thermal expansion rate is small, and it is easy to manufacture photomasks. Further, as the above-described transparent substrate, a resin substrate can also be used.

[0103] The light transmittance of the transparent substrate is not particularly limited as long as it is the same degree as that of a transparent substrate for a general photomask.

[0104] The thickness of the transparent substrate can be appropriately selected depending on the use of the photomask blank according to the present application or the like.

[0105] 3. Use

[0106] The photomask blank according to the present application is preferably used for the manufacture of a binary mask.

[0107] In addition, the photomask blank according to the present application is preferably a large photomask blank for manufacturing a large photomask. The size of the large photomask blank can be, for example, a size in which at least one side has a length of 350 mm or more.

[0108] B. Photomask

[0109] The photomask according to the present application is a photomask having a transparent substrate, and a light-shielding pattern including a chromium-based material disposed on one face of the transparent substrate, and a sheet resistance of the light-shielding pattern is within a prescribed range.

[0110] Figure 3 A schematic cross-sectional view of the photomask according to the present application is shown. As shown in FIG. 1, a photomask 10 has a transparent substrate 12, and a light-shielding pattern 13 including a chromium-based material disposed on one face of the transparent substrate 12. The sheet resistance of the light-shielding pattern 13 is within a prescribed range. Figure 3 In the example shown in FIG. 1, the light-shielding pattern 13 has, in order from the transparent substrate 2 side, a light-shielding layer 13a and a low-reflection layer 13b, but is not limited thereto. Figure 3

[0111] According to the present application, the sheet resistance of the light-shielding pattern is high up to the above range, and thus when static electricity carried in the photomask is discharged, the current flowing through the light-shielding pattern can be reduced. Then, the heat generated by the discharge current can be reduced. As a result, the static electricity damage can be suppressed.

[0112] In addition, according to the present application, by adjusting the composition of the light-shielding pattern including the chromium-based material, for example, the sheet resistance of the light-shielding pattern can be adjusted, and thus the photomask can be manufactured by a simple process without a complicated process.

[0113] Hereinafter, each component in the photomask according to the present application will be described.

[0114] 1. Light-shielding pattern

[0115] The light-shielding pattern according to the present application is a member disposed on one face of a transparent substrate and including a chromium-based material, and a sheet resistance is within a prescribed range.

[0116] ​Note that the light-shielding pattern can have the same thin layer resistance, optical density, thickness, and the like as the light-shielding film of the above-described photomask blank, and thus the description thereof is omitted here.

[0117] The width of the light-shielding pattern is not particularly limited and can be, for example, 0.1 μm or more and 10 μm or less.

[0118] The shape of the light-shielding pattern, the distance between adjacent light-shielding patterns, and the like can be appropriately adjusted according to the use of the photomask of the present application and the like.

[0119] The light-shielding pattern contains a chromium-based material and has a thin layer resistance within the above-described range, and can have a plurality of layers or be a film whose composition changes in the thickness direction. Hereinafter, the case where the light-shielding pattern has a plurality of layers (first embodiment) and the case where the light-shielding pattern is a film whose composition changes in the thickness direction (second embodiment) are described.

[0120] (1) First Embodiment of Light-Shielding Pattern

[0121] The light-shielding pattern of the present embodiment contains a chromium-based material, has a thin layer resistance within a prescribed range, and has a plurality of layers.

[0122] The light-shielding pattern contains a chromium-based material, has a thin layer resistance within a prescribed range, and has a plurality of layers, and preferably has a light-shielding layer and a low-reflection layer in this order from the transparent substrate side. For example, in Figure 3 , the light-shielding pattern 13 has a light-shielding layer 13a and a low-reflection layer 13b in this order from the transparent substrate 12 side. The reasons for the preference are the same as those of the light-shielding film of the first embodiment of the above-described photomask blank, and thus the description thereof is omitted here.

[0123] In addition, the light-shielding pattern can have a low-reflection layer between the transparent substrate and the light-shielding layer. That is, for example, as shown in Figure 4 , the light-shielding pattern 13 can have a second low-reflection layer 13c, a light-shielding layer 13a, and a first low-reflection layer 13b in this order from the transparent substrate 12 side.

[0124] Note that in the present specification, the low-reflection layer disposed on the side of the light-shielding pattern opposite the transparent substrate is referred to as a first low-reflection layer, and the low-reflection layer disposed on the side of the light-shielding pattern close to the transparent substrate is referred to as a second low-reflection layer.

[0125] Each layer constituting the light-shielding pattern of the first embodiment can be the same as the light-shielding film of the first embodiment of the above-described photomask blank, and thus the description thereof is omitted here.

[0126] (2) Second Embodiment of Light-Shielding Pattern

[0127] The light-blocking pattern of the present embodiment is a film containing a chromium-based material, having a sheet resistance within a prescribed range, and having a composition that varies in the thickness direction.

[0128] Note that the light-blocking pattern of the second embodiment can be configured to be the same as the light-blocking film of the second embodiment in the above-described photomask blank, and thus the description thereof is omitted here.

[0129] 2. Transparent substrate

[0130] The transparent substrate of the present application is a member that supports the above-described light-blocking pattern, and has light-transmitting properties. Note that the transparent substrate can be configured to be the same as the transparent substrate in the above-described photomask blank.

[0131] 3. Method for manufacturing photomask

[0132] As the method for manufacturing a photomask of the present application, there is no particular limitation as long as it is a method that can manufacture a photomask having the above-described configuration, and it can be configured to be the same as a general method for manufacturing a photomask.

[0133] For example, first, a mask blank having a light-blocking film on one face of a transparent substrate is prepared. Next, a resist pattern of a desired shape is formed on the light-blocking film, and the light-blocking film is etched using the resist pattern as a mask, thereby forming a light-blocking pattern from the light-blocking film. Thus, a photomask is produced.

[0134] 4. Photomask

[0135] The photomask of the present application is preferably a large photomask. The size of the large photomask can be configured to be the same as the size of the above-described large photomask blank.

[0136] Note that the present application is not limited to the above-described embodiments. The above-described embodiments are examples, and technical solutions having the technical idea and substantially the same configuration described in the claims of the present application, and achieving the same effects are included in the technical scope of the present application.

[0137] Example

[0138] The following shows examples and comparative examples, and more specifically describes the present application.

[0139] [Example 1]

[0140] First, a mask blank was produced, which had a 6-inch square precisely polished synthetic quartz glass, and a light-blocking film having a laminated structure of a second low-reflection layer with a film thickness of 30 nm, a light-blocking layer with a film thickness of 150 nm, and a first low-reflection layer with a film thickness of 30 nm, which were sequentially laminated, disposed on the surface of the synthetic quartz glass.

[0141] In the production of the mask blank, the light shielding film was formed by using a sputtering method to form films on the surface of the synthetic quartz glass in the order of the second low reflection layer, the light shielding layer, and the first low reflection layer. At this time, the formation of the second low reflection layer, the light shielding layer, and the first low reflection layer was performed using a sputtering device in which the gas was changed, respectively. In addition, regarding the second low reflection layer, the light shielding layer, and the first low reflection layer, a Cr target was assembled in a vacuum chamber, O2, N2, CO2 gas was introduced, and the formation was performed by reactive sputtering in a vacuum environment. The formation conditions of the light shielding layer were set to conditions in which the ratio of O2 gas was increased compared to the formation conditions of the light shielding film of a general binary mask. In addition, the formation conditions of the first low reflection layer and the second low reflection layer were set to conditions equivalent to the formation conditions of the low reflection film in the light shielding pattern of a general binary mask.

[0142] Next, a resist pattern was formed on the above light shielding film, and the light shielding film was etched using the resist pattern as an etching mask to form a light shielding pattern having Figure 5 (a) and (b) shown. Thus, a photomask was produced.

[0143] Note that, Figure 5 (a) and (b) are schematic plan views of a photomask, Figure 5 (a) is an overall view of a 6-inch square photomask, Figure 5 (b) is Figure 5 (a) is an enlarged view of a portion A of (a). In addition, in Figure 5 (b), the light shielding pattern 13' is a line pattern, the line width is 10 μm, and 40 lines are provided. In addition, the distance d between adjacent light shielding patterns 13' was changed to be between 2 μm and 15 μm, and thus a photomask was produced.

[0144] [Example 2]

[0145] First, a mask blank was produced, which had a 6-inch square precisely polished synthetic quartz glass, and a light shielding film provided on the surface of the synthetic quartz glass and having a laminated structure in which a second low reflection layer having a film thickness of 30 nm, a light shielding layer having a film thickness of 120 nm, and a first low reflection layer having a film thickness of 30 nm were sequentially laminated. The production method of the mask blank was set to be the same as that of Example 1.

[0146] Next, a photomask was produced by the same operation as in Example 1.

[0147] [Comparative Example 1]

[0148] First, a mask blank was produced, which had a 6-inch square precisely polished synthetic quartz glass, and a light shielding film provided on the surface of the synthetic quartz glass and having a laminated structure in which a light shielding layer having a film thickness of 85 nm and a low reflection layer having a film thickness of 30 nm were sequentially laminated.

[0149] In the production of the mask blank, the light shielding film was formed by using a sputtering method to form films on the surface of the synthetic quartz glass in the order of the light shielding layer and the low reflection layer. At this time, the formation of the light shielding layer and the low reflection layer was performed using a sputtering device in which the gas was changed, respectively. In addition, with respect to the low reflection layer, a Cr target was installed in a vacuum chamber, O2, N2, CO2 gas was introduced, and the film was formed by reactive sputtering in a vacuum environment. The film formation conditions of the low reflection layer were set to be the same as the film formation conditions of the low reflection film in the light shielding pattern of a general binary mask. Further, the film formation conditions of the light shielding layer were set to be the same as the film formation conditions of the chromium film in the light shielding pattern of a general binary mask.

[0150] Next, the photomask was produced in the same manner as in Example 1.

[0151] [Example 3]

[0152] The photomask blank and the photomask were produced in the same manner as in Example 1 except that the size was changed. The size was set to 800 mm x 920 mm.

[0153] [Comparative Example 2]

[0154] The photomask was produced in the same manner as in Comparative Example 1 except that the size was changed. The size was set to 1220 mm x 1400 mm.

[0155] [Example 4]

[0156] First, a mask blank was produced, which had a 6-inch square precisely polished synthetic quartz glass, and a light shielding film having a laminated structure in which a second low reflection layer having a film thickness of 30 nm, a light shielding layer having a film thickness of 140 nm, and a first low reflection layer having a film thickness of 30 nm were sequentially laminated, was disposed on the surface of the synthetic quartz glass. The production method of the mask blank was set to be the same as in Example 1.

[0157] Next, the photomask was produced in the same manner as in Example 1.

[0158] [Comparative Example 3]

[0159] First, a mask blank was produced, which had a 6-inch square precisely polished synthetic quartz glass, and a light shielding film having a laminated structure in which a second low reflection layer having a film thickness of 30 nm, a light shielding layer having a film thickness of 140 nm, and a first low reflection layer having a film thickness of 30 nm were sequentially laminated, was disposed on the surface of the synthetic quartz glass. The production method of the mask blank was set to be the same as in Example 1.

[0160] Next, the photomask was produced in the same manner as in Example 1.

[0161] [Comparative Example 4]

[0162] First, a mask blank was produced, which had a 6-inch square precisely polished synthetic quartz glass, and a light shielding film having a laminated structure of a second low reflection layer with a film thickness of 30 nm, a light shielding layer with a film thickness of 150 nm, and a first low reflection layer with a film thickness of 39 nm, which were sequentially laminated, disposed on the surface of the synthetic quartz glass. The production method of the mask blank was set to be the same as that of Example 1.

[0163] Next, a photomask was produced by the same operation as in Example 1.

[0164] (Evaluation)

[0165] (1) Sheet Resistance

[0166] The sheet resistance of the light shielding film was measured for the 6-inch square photomask blanks of Examples 1 to 2 and 4 and Comparative Examples 1, 3, and 4. The measurement of the sheet resistance was performed by a four-terminal four-probe method using a low resistivity meter Loresta-GX MCP-T700 manufactured by Mitsubishi Chemical Corporation, and using an ASP probe manufactured by Mitsubishi Chemical Corporation. The sheet resistance was measured 10 times, and the average value was set. The results are shown in Table 1.

[0167] [Table 1]

[0168]

[0169] (2) Composition Analysis

[0170] The composition analysis of the light shielding film was performed by XPS analysis for the 6-inch square photomask blanks of Examples 1 to 2 and 4 and Comparative Examples 1, 3. Specifically, the light shielding film was subjected to ion etching using Quantum 2000 manufactured by ULVAC-PHI, Inc. as an X-ray photoelectron spectrometer device, and the surface of the exposed light shielding layer was subjected to composition analysis. The measurement conditions are described below. The results are shown in Table 2.

[0171] • Incident X-ray: Monochromated Al Kα line

[0172] • X-ray irradiation area (measurement area): 200 μmφ

[0173] • X-ray output power: 30 W

[0174] • Photoelectron acquisition angle: 45°

[0175] • Charge neutralization condition: Electron neutralization gun (0.02 mA), low acceleration Ar + Ion irradiation

[0176] • Measurement peak: Cr2p, Si2p, C1s, N1s, O1s

[0177] • Quantitative: Background was obtained by the Shirley method, and atomic ratio was calculated from the peak area obtained using the relative sensitivity coefficient method.

[0178] [Table 2]

[0179]

[0180] The light-shielding layer of Example 1 was Cr: 88.6 at.%, C: 2.4 at.%, O: 7.6 at.%. The light-shielding layer of Example 2 was Cr: 91.1 at.%, C: 1.9 at.%, O: 5.8 at.%. The light-shielding layer of Comparative Example 1 was Cr: 92.4 at.%, C: 1.2 at.%, O: 4.4 at.%.

[0181] (3) Static electricity resistance

[0182] For the 6-inch square photomasks of Examples 1 to 2, 4 and Comparative Examples 1, 3, static electricity resistance was evaluated using an electrostatic tester ESS-6008 manufactured by NOISE Research Co., Ltd. The measurement conditions were set to voltage 500 V, capacitance 100 pF ± 10%, and resistance 1.5 kΩ ± 1%. Specifically, after the parts of X and Y in (b) were charged to 500 V, the occurrence of static electricity damage was confirmed by observing the adjacent light-shielding patterns 13' using a microscope. The case where no static electricity damage occurred was evaluated as "O", and the case where static electricity damage occurred was evaluated as "X". The results are shown in Table 3. Note that the smaller the distance d between the adjacent light-shielding patterns, the more likely static electricity damage occurs. Figure 5

[0183] [Table 3]

[0184] d (pm) Example 1 Example 2 Example 4 Comparative Example 1 Comparative Example 3 2 × × × × × 3 × × × × × 4 × × × × × 5 × × × × × 6 × × × × × 7 ○ × × × × 8 ○ × × × × 9 ○ ○ × × × 10 ○ ○ ○ × × 15 ○ ○ ○ ○ ○

[0185] In addition, for the photomasks of Example 3 and Comparative Example 2, static electricity resistance was also evaluated in the same manner as described above. The results are shown in Table 4.

[0186] [Table 4]

[0187] d (pm) Example 3 Comparative Example 2 2 ○ × 3 ○ × 4 ○ × 5 ○ × 6 ○ × 7 ○ × 8 ○ × 9 ○ ○ 10 ○ ○ 15 ○ ○

[0188] As is clear from Tables 3 to 4, the photomasks of Examples 1 to 4 have excellent static electricity resistance.

[0189] (4) Plate-making property

[0190] ​Comparative Example 4 has a thicker film thickness of the first low-reflective layer than Example 1, and thus the first low-reflective layer is etched for a longer time than the light-shielding layer and the second low-reflective layer, and a difference in cross-sectional shape is likely to occur between the upper layer and the lower layer of the light-shielding film. A vertical cross-sectional shape is required in a photomask, but in Comparative Example 4, it is difficult to maintain the cross-sectional shape, particularly in a fine line, and the plate-making properties are poor.

[0191] Explanation of symbols

[0192] 1...photomask blank

[0193] 2, 12...transparent substrate

[0194] 3...light-shielding film

[0195] 3a, 13a...light-shielding layer

[0196] 3b, 13b...low-reflective layer (first low-reflective layer)

[0197] 3c, 13c...second low-reflective layer

[0198] 10...photomask

[0199] 13...light-shielding pattern

Claims

1. A photomask blank having a transparent substrate, and a light-shielding film provided on one surface of the transparent substrate and containing a chromium-based material, The light shielding film has a sheet resistance of 10 5 Ω / DOT or more and 10 7 Ω / DOT or less, the light-shielding film has, in order from the transparent substrate side, a second low-reflection layer, a light-shielding layer, and a first low-reflection layer, the second low-reflection layer, the first low-reflection layer, and the light-shielding layer contain a chromium-based material containing oxygen.

2. The photomask blank of claim 1, wherein, the thickness of the light-shielding layer is 100 nm or more and 200 nm or less.

3. The photomask blank of claim 1, wherein, the oxygen atom content ratio in the first low-reflection layer and the second low-reflection layer is higher than the oxygen atom content ratio in the light-shielding layer.

4. The photomask blank of claim 1, wherein, the oxygen atom content ratio in the light-shielding layer is 7 atomic% or more and 20 atomic% or less.

5. A photomask blank having a transparent substrate, and a light-shielding film provided on one surface of the transparent substrate and containing a chromium-based material containing oxygen, the light-shielding film has, in order from the transparent substrate side, a second low-reflection layer, a light-shielding layer, and a first low-reflection layer, the thickness of the light-shielding layer is 100 nm or more and 200 nm or less, the oxygen atom content ratio in the light-shielding layer is 7 atomic% or more and 20 atomic% or less.

6. The photomask blank according to any one of claims 1 to 5, wherein, the thickness of the light-shielding film is 140 nm or more and 280 nm or less.

7. The photomask blank according to any one of claims 1 to 5, which is a large photomask blank having a length of one side of 350 mm or more.

8. A photomask having a transparent substrate, and a light-shielding pattern provided on one surface of the transparent substrate and containing a chromium-based material, The sheet resistance of the light-shielding pattern is 10 5 Ω / DOT or more and 10 7 Ω / DOT or less, the light-shielding pattern has, in order from the transparent substrate side, a second low-reflection layer, a light-shielding layer, and a first low-reflection layer, the second low-reflection layer, the first low-reflection layer, and the light-shielding layer contain a chromium-based material containing oxygen.

9. The photomask of claim 8, wherein, the thickness of the light-shielding layer is 100 nm or more and 200 nm or less.

10. The photomask of claim 8, wherein, the oxygen atom content ratio in the first low-reflection layer and the second low-reflection layer is higher than the oxygen atom content ratio in the light-shielding layer.

11. The photomask of claim 8, wherein, the oxygen atom content ratio in the light-shielding layer is 7 atomic% or more and 20 atomic% or less.

12. A photomask having a transparent substrate, and a light-shielding pattern provided on one surface of the transparent substrate and containing a chromium-based material containing oxygen, the light-shielding pattern has, in order from the transparent substrate side, a second low-reflection layer, a light-shielding layer, and a first low-reflection layer, the thickness of the light-shielding layer is 100 nm or more and 200 nm or less, the oxygen atom content ratio in the light-shielding layer is 7 atomic% or more and 20 atomic% or less.

13. The photomask according to any one of claims 8 to 12, wherein, the thickness of the light-shielding pattern is 140 nm or more and 280 nm or less.

14. The photomask according to any one of claims 8 to 12, wherein, the photomask is a large photomask having a length of one side of 350 mm or more.

Images