Phase shift mask blank, method for manufacturing phase shift mask blank, phase shift mask, and method for manufacturing phase shift mask

Abstract

The invention relates to a phase shift mask blank, a method for manufacturing the phase shift mask blank, a phase shift mask, and a method for manufacturing the phase shift mask. The phase shift mask blank of the present invention is a phase shift mask blank having a mask layer serving as a phase shift mask. The phase shift mask blank has a transparent substrate and a phase shift layer. The phase shift layer is laminated on the transparent substrate. The phase shift layer is made of metal silicide. The phase shift layer includes nitrogen, molybdenum, and silicon. The average value of the ratio Si / Mo of the composition ratio (atm%) of silicon to the composition ratio (atm%) of molybdenum is in the range of 2.2-3.2.

Description

Technical Field

[0001] The present invention relates to a technology suitable for use in a phase-shift mask blank, a method for manufacturing a phase-shift mask blank, a phase-shift mask, and a method for manufacturing a phase-shift mask. Background Art

[0002] In the manufacture of flat panel displays (FPDs) such as liquid crystal displays and organic electroluminescent displays, or in the manufacture of semiconductor devices, not only conventional masks using light-shielding films but also edge-enhancement phase-shift masks are sometimes used.

[0003] In some cases, a phase-shift mask is manufactured by forming a phase-shift layer on a quartz substrate using a silicide film as the mask layer. This layer is set, for example, to have a transmittance of 5% or 20% for the I-line (wavelength 365nm) and a phase of approximately 180°. Therefore, the optical constants and film thickness of the phase-shift layer must be adjusted in advance.

[0004] When forming a phase shift layer using molybdenum silicide as a phase shift mask, wet etching using a predetermined etching solution (etchant) is used to form a desired pattern. In addition, a cleaning solution such as alkali is used for cleaning.

[0005] Patent Document 1: Japanese Patent No. 7381374

[0006] The permissible range of optical properties for each of the multiple layers that make up the photomask is extremely narrow. Consequently, the degree of freedom in adjusting the optical density and film thickness of each layer is limited. Furthermore, in order to reduce the width of the pattern formed on the photomask, even stricter cross-sectional perpendicularity is required.

[0007] Furthermore, even slight variations in the thickness of each of the multiple layers that comprise the mask layer can degrade the properties required of the mask layer. Therefore, each layer is required to exhibit higher chemical resistance to etching or cleaning solutions. However, etching layers with higher chemical resistance takes longer, adversely affecting exposed areas outside the intended area. For example, this can lead to roughening of the glass substrate surface, undesirable variations in film thickness, and degradation of the cross-sectional shape due to poor etching.

[0008] Therefore, shortening of etching time is also required.

[0009] Wet etching of molybdenum silicide films requires the use of an etchant containing hydrofluoric acid. Consequently, overetching during molybdenum silicide etching can cause etching of the glass substrate due to the presence of hydrofluoric acid in the etchant. Longer wet etching times for the phase shift film inevitably increase the overetching time as well. This poses the following problems: Pattern formation can damage transparent substrates such as glass, and the optical properties required for the phase shift mask may deviate from the specified range. Therefore, it is best to minimize the wet etching time.

[0010] Furthermore, there is a trade-off between shortening the wet etching time and chemical resistance. Specifically, using a phase shift film with a shorter wet etching time results in poor chemical resistance to alkaline solutions. Alkaline solutions are used in the cleaning process during mask production. Consequently, poor chemical resistance can alter the properties of the phase shift mask during the cleaning process. Summary of the Invention

[0011] The present invention has been made in view of the above circumstances, and aims to achieve the following objectives.

[0012] 1. Simultaneously achieve shortened etching time and improved chemical resistance in phase shift phase.

[0013] 2. Achieve composition accuracy and maintain optical properties at the same time.

[0014] 3. Simultaneously reduce the roughness and defects of the glass substrate.

[0015] For phase shift masks and phase shift mask blanks, film formation conditions such as film thickness and composition are generally set to control patterning accuracy and optical properties. Conventionally, there has been a technical concept for controlling the film composition of molybdenum silicide films in the following manner.

[0016] In order to improve chemical resistance, the following film composition control method is adopted.

[0017] Increase nitrogen (N) in the film composition.

[0018] Reduce oxygen (O) in the film composition.

[0019] Reduce carbon (C) in the film composition.

[0020] Reduce molybdenum (Mo) in the film composition.

[0021] Increase the substrate temperature during film formation.

[0022] Reduce the film forming pressure during film formation.

[0023] Chemical resistance can be improved by selecting one or more of these control methods. However, using any of these control methods will result in a longer etching time.

[0024] On the contrary, in order to shorten the etching time, the following film composition control method is adopted.

[0025] Reduce nitrogen (N) in the film composition.

[0026] Increase oxygen (O) in the film composition.

[0027] Increase carbon (C) in the film composition.

[0028] Increase molybdenum (Mo) in the film composition.

[0029] Lower the substrate temperature during film formation.

[0030] Increase the film forming pressure during film formation.

[0031] Etching time can be shortened by selecting one or more of these control methods. However, any of these control methods will result in a decrease in chemical resistance. Furthermore, if oxygen (O) is added to the film composition, defect quality will deteriorate.

[0032] Conventionally, in order to form a film with the necessary optical properties (optical density, refractive index, transmittance, etc.), the above-mentioned various control methods have been combined to adjust the optical properties. However, with these conventional control methods, there is a trade-off between chemical resistance and shortened etching time.

[0033] In this regard, the present inventors have conducted repeated and intensive studies and found the following facts.

[0034] As mentioned above, if oxygen (O) is mixed in a molybdenum silicon film, the etching time will be shortened. Therefore, it can be seen that in the case of a molybdenum silicon film with a high silicon (Si) ratio (MoSi7.0-15.0), the etching time is longer.

[0035] Furthermore, while adding CO2 gas during the formation of molybdenum silicon films typically shortens etching time, in the case of molybdenum silicon films with a high silicon (Si) ratio (MoSi 7.0-15.0), even a small amount of CO2 added during film formation does not allow for etching.

[0036] Here, the numerical value "7.0 to 15.0" in "MoSi7.0 to 15.0" represents the ratio of silicon to molybdenum.

[0037] Generally, when the film composition of the molybdenum silicon film contains more molybdenum (Mo) and less silicon (Si), wet etching proceeds continuously and the etching time becomes shorter.

[0038] In contrast, when the molybdenum silicon film has a low content of molybdenum (Mo) and a high content of silicon (Si) in its film composition, wet etching cannot be continued and the etching time becomes long.

[0039] This is considered to be because the etching difficulty of the molybdenum silicon film changes depending on the ratio between molybdenum trioxide, which is easily dissolved by wet etching, and silicon oxide, which is not easily dissolved by wet etching.

[0040] The present inventors have discovered that the boundary value at which the etching difficulty of the molybdenum silicon film changes is near Mo:Si=1:7.0 (MoSi7.0).

[0041] Generally speaking, if nitrogen (N) is mixed into a molybdenum silicon film, the etching time will be prolonged. In addition, if nitrogen (N) is mixed into a molybdenum silicon film, the transmittance will be increased.

[0042] In contrast, in the case of a molybdenum-silicon film (MoSi7.0-15.0) with a high silicon (Si) ratio, the transmittance is improved due to the low molybdenum (Mo) content. Therefore, in the case of a molybdenum-silicon film (MoSi7.0-15.0) with a high silicon (Si) ratio, the transmittance is not reduced even if the nitrogen (N) content is low.

[0043] The inventors discovered that when forming a molybdenum silicon thin film (MoSi7.0 to 15.0 or so) with a high silicon (Si) ratio, when the film-forming gases provided are Ar gas and N2 gas, even if the gas ratio Ar / N2 is increased by reducing the amount of N2 gas relative to Ar gas, the transmittance of 5% under line I can be met.

[0044] In this case, the nitrogen (N) content in the molybdenum silicon film composition is reduced, thereby shortening the etching time of the molybdenum silicon film (MoSi7.0-15.0). In addition, since no oxygen (O) is added, the amount of molybdenum trioxide does not increase, thereby improving the chemical resistance of the molybdenum silicon film (MoSi7.0-15.0).

[0045] Conventionally, the substrate was heated during molybdenum silicon film deposition. However, it has been discovered that etching time is shortened when the substrate is deposited without heating. The mechanism for this is unclear, but it is believed that heating-induced changes in film properties (film density and oxidation level) hinder etching.

[0046] Alternatively, the etching time can be shortened by forming a molybdenum silicon film under high pressure. However, in this case, chemical resistance deteriorates as a trade-off.

[0047] The present inventors have discovered that by setting the film forming conditions to predetermined conditions, the chemical resistance of the molybdenum silicon film can be improved by low-pressure film forming, and the etching time can also be shortened by low-pressure film forming.

[0048] In summary, the present inventors have found a range in which the etching time can be shortened while maintaining chemical resistance while keeping the etching time short.

[0049] A molybdenum silicon film (MoSi7.0-15.0) having a high silicon (Si) ratio is used.

[0050] The film-forming gases are Ar and N2 only.

[0051] The film formation was performed under the following conditions: the Ar gas ratio in the supply gas was increased and oxygen (O) was not added, so that nitridation was performed but oxidation was not performed, the film formation pressure was reduced, and the substrate was not heated.

[0052] Thus, the present inventors have achieved a molybdenum silicon film having both high chemical resistance and short etching time, thereby completing the present invention.

[0053] In order to solve the above-mentioned problems, the present invention adopts the following configuration.

[0054] A phase-shift mask blank according to one embodiment of the present invention includes a mask layer serving as a phase-shift mask. The phase-shift mask blank includes a transparent substrate and a phase-shift layer formed of a metal silicide and laminated on the transparent substrate. The phase-shift layer includes nitrogen, molybdenum, and silicon, and the average value of the ratio of silicon (atm%) to molybdenum (atm%), Si / Mo, is within a range of 2.2 to 3.2.

[0055] The phase shift mask blank according to one aspect of the present invention may include a light shielding layer containing chromium stacked on the phase shift layer.

[0056] In the phase shift mask blank according to one aspect of the present invention, in the phase shift layer, an average value of a ratio N / Si of a nitrogen composition ratio (atm %) to a silicon composition ratio (atm %) may be within a range of 0.50 to 0.65.

[0057] In the phase shift mask blank according to one embodiment of the present invention, in the phase shift layer, an average value of the ratio Si / (Mo+N) of the composition ratio (atm%) of silicon to the sum of the composition ratio (atm%) of molybdenum and the composition ratio (atm%) of nitrogen can be in the range of 1.00 to 1.13.

[0058] In the phase shift mask blank according to one embodiment of the present invention, in the phase shift layer, an average value of the ratio N / (Mo+Si) of the composition ratio (atm%) of nitrogen to the sum of the composition ratio (atm%) of molybdenum and the composition ratio (atm%) of silicon can be in the range of 0.35 to 0.50.

[0059] In the phase shift mask blank according to one aspect of the present invention, in the phase shift layer, an average value of a ratio N / Mo of a nitrogen composition ratio (atm %) to a molybdenum composition ratio (atm %) may be within a range of 1.4 to 1.75.

[0060] In the phase shift mask blank according to one embodiment of the present invention, in the phase shift layer, an average value of the sum of the molybdenum composition ratio (atm%), the silicon composition ratio (atm%), and the nitrogen composition ratio (atm%) may be greater than 90.

[0061] In the phase shift mask blank according to one embodiment of the present invention, in the phase shift layer, an average value of a ratio O / Si of an oxygen composition ratio (atm %) to a silicon composition ratio (atm %) detected by Auger electron spectroscopy may be within a range of 0.01 to 0.15.

[0062] A method for manufacturing a phase shift mask blank according to one embodiment of the present invention is used to manufacture the phase shift mask blank according to the above embodiment. In this method, when forming the phase shift layer, sputtering is performed using a target having a composition in which the ratio of molybdenum to silicon is set to 7.0≤Si / Mo≤15.0.

[0063] In the method for manufacturing a phase shift mask blank according to one aspect of the present invention, when forming the phase shift layer, sputtering may be performed while supplying argon gas and nitrogen gas.

[0064] A phase shift mask manufacturing method according to one aspect of the present invention uses a phase shift mask blank manufactured by the phase shift mask blank manufacturing method according to the above aspect, and patterns the phase shift mask blank by wet etching to manufacture a phase shift mask.

[0065] A phase shift mask according to one aspect of the present invention is manufactured by the method for manufacturing a phase shift mask according to the above aspect.

[0066] A phase-shift mask blank according to one embodiment of the present invention includes a mask layer serving as a phase-shift mask. The phase-shift mask blank includes a transparent substrate and a phase-shift layer formed of a metal silicide and laminated on the transparent substrate. The phase-shift layer includes nitrogen, molybdenum, and silicon, and the average value of the ratio of silicon (atm%) to molybdenum (atm%), Si / Mo, is within a range of 2.2 to 3.2.

[0067] In the above configuration, the phase-shift layer is composed of molybdenum, silicon, and nitrogen, and contains no added oxygen, thus improving chemical resistance. While the lack of added oxygen in the phase-shift layer naturally increases etching time, this can be shortened by setting the molybdenum to silicon ratio within the above range. Since the phase-shift layer contains no added oxygen and contains nitrogen, its transmittance is increased, reaching approximately 5% under line I.

[0068] Furthermore, the phase-shift layer prevents further etching because of its high silicon content relative to molybdenum. Furthermore, the layer lacks oxygen, suppressing defects while improving transmittance.

[0069] Therefore, the phase-shift layer can achieve both high chemical resistance and short etching time.

[0070] The phase shift mask blank according to one aspect of the present invention may include a light shielding layer containing chromium stacked on the phase shift layer.

[0071] The above configuration maintains the chemical resistance of the phase-shift layer surface. It shortens the etching time for the phase-shift layer. It optimizes the pattern shapes formed on the phase-shift layer and the light-shielding layer. It suppresses changes in the thickness of the phase-shift layer caused by hydrofluoric acid. It also maintains the phase-shift properties of the phase-shift layer. These effects can be achieved simultaneously.

[0072] Furthermore, the etching rate of the phase-shift layer, which is a molybdenum silicide film, can be increased. This allows for the formation of a phase-shift pattern through rapid etching. Consequently, when manufacturing a phase-shift mask from a phase-shift mask blank, that is, when forming a phase-shift pattern from the phase-shift layer, the necessary etching time can be shortened, even when etching the phase-shift layer using an etchant containing hydrofluoric acid.

[0073] Even when etching the phase-shift layer with an etchant containing hydrofluoric acid, over-etching is suppressed. The effects of hydrofluoric acid on etching of a transparent glass substrate (quartz substrate) are reduced. The phase-shift characteristics caused by etching the glass substrate are not altered. Because the defect quality of the phase-shift layer is not degraded, problems such as failure to form a phase-shift pattern when forming the phase-shift layer are avoided.

[0074] Furthermore, the surface of the phase shift layer maintains high chemical resistance. During the cleaning process, changes in film thickness caused by cleaning solutions such as alkali can be prevented. This also maintains the phase shift properties of the phase shift layer. These advantages can be achieved simultaneously.

[0075] In the phase shift mask blank according to one aspect of the present invention, in the phase shift layer, an average value of a ratio N / Si of a nitrogen composition ratio (atm %) to a silicon composition ratio (atm %) may be within a range of 0.50 to 0.65.

[0076] In this structure, the phase-shift layer has a nitrogen-to-silicon ratio within the aforementioned range and lacks oxygen, thereby improving chemical resistance. While the absence of oxygen in the phase-shift layer naturally increases etching time, maintaining the nitrogen-to-silicon ratio within the aforementioned range shortens etching time. Since the phase-shift layer lacks oxygen and contains nitrogen, its transmittance is increased, reaching approximately 5% under line I.

[0077] Furthermore, by keeping the nitrogen-to-silicon ratio within the aforementioned range, the phase-shift layer can prevent further etching. Because the phase-shift layer contains a high amount of silicon, the nitrogen-to-silicon ratio is within the aforementioned range, and no oxygen is added, it can suppress defects while improving transmittance.

[0078] Therefore, both higher chemical resistance of the phase-shift layer and shorter etching time can be achieved.

[0079] In the phase shift mask blank according to one embodiment of the present invention, in the phase shift layer, an average value of the ratio Si / (Mo+N) of the composition ratio (atm%) of silicon to the sum of the composition ratio (atm%) of molybdenum and the composition ratio (atm%) of nitrogen can be in the range of 1.00 to 1.13.

[0080] In the above structure, the phase-shift layer has a silicon ratio relative to the sum of nitrogen and molybdenum within the above-mentioned range and lacks oxygen addition, thereby improving chemical resistance. While the absence of oxygen in the phase-shift layer naturally increases etching time, maintaining the silicon ratio relative to the sum of nitrogen and molybdenum within the above-mentioned range shortens etching time. Since the phase-shift layer lacks oxygen and contains nitrogen, its transmittance is increased, reaching approximately 5% under line I.

[0081] Furthermore, by setting the ratio of silicon to the sum of nitrogen and molybdenum within the aforementioned range, the phase-shift layer can prevent further etching. Since the phase-shift layer contains a high amount of silicon, the ratio of silicon to the sum of nitrogen and molybdenum is within the aforementioned range, and no oxygen is added, the generation of defects can be suppressed while improving transmittance.

[0082] Therefore, a higher chemical resistance and a shorter etching time can be achieved in the phase-shift layer.

[0083] In the phase shift mask blank according to one embodiment of the present invention, in the phase shift layer, an average value of the ratio N / (Mo+Si) of the composition ratio (atm%) of nitrogen to the sum of the composition ratio (atm%) of molybdenum and the composition ratio (atm%) of silicon can be in the range of 0.35 to 0.50.

[0084] In the above structure, the phase-shift layer has a nitrogen ratio relative to the sum of silicon and molybdenum within the above-mentioned range and lacks oxygen, thereby improving chemical resistance. While the absence of oxygen in the phase-shift layer naturally increases etching time, by setting the nitrogen ratio relative to the sum of silicon and molybdenum within the above-mentioned range, etching time can be shortened. Since the phase-shift layer lacks oxygen and contains nitrogen, its transmittance is increased, reaching approximately 5% under line I.

[0085] Furthermore, by setting the ratio of nitrogen to the sum of silicon and molybdenum within the aforementioned range, the phase-shift layer can prevent further etching. Since the phase-shift layer contains a high amount of silicon, the ratio of nitrogen to the sum of silicon and molybdenum is within the aforementioned range, and no oxygen is added, the generation of defects can be suppressed while improving transmittance.

[0086] Therefore, a higher chemical resistance and a shorter etching time can be achieved in the phase-shift layer.

[0087] In the phase shift mask blank according to one aspect of the present invention, in the phase shift layer, an average value of a ratio N / Mo of a nitrogen composition ratio (atm %) to a molybdenum composition ratio (atm %) may be within a range of 1.4 to 1.75.

[0088] In the above structure, the phase-shift layer has a nitrogen-to-molybdenum ratio within the above-mentioned range and lacks oxygen, thereby improving chemical resistance. While the lack of oxygen in the phase-shift layer naturally increases etching time, maintaining the nitrogen-to-molybdenum ratio within the above-mentioned range shortens etching time. Since the phase-shift layer lacks oxygen and contains nitrogen, its transmittance is increased, reaching approximately 5% under line I.

[0089] Furthermore, by setting the nitrogen-to-molybdenum ratio within the aforementioned range, the phase-shift layer can prevent further etching. Because the phase-shift layer contains a high amount of silicon, the nitrogen-to-molybdenum ratio is within the aforementioned range, and no oxygen is added, the generation of defects can be suppressed while improving transmittance.

[0090] Therefore, a higher chemical resistance and a shorter etching time can be achieved in the phase-shift layer.

[0091] In the phase shift mask blank according to one embodiment of the present invention, in the phase shift layer, an average value of the sum of the molybdenum composition ratio (atm%), the silicon composition ratio (atm%), and the nitrogen composition ratio (atm%) may be greater than 90.

[0092] In this structure, the phase-shift layer has a silicon-to-nitrogen ratio within the aforementioned range and lacks oxygen, thereby improving chemical resistance. While the absence of oxygen in the phase-shift layer naturally increases etching time, maintaining the silicon-to-nitrogen ratio within the aforementioned range shortens etching time. Since the phase-shift layer lacks oxygen and contains nitrogen, its transmittance is increased, reaching approximately 5% under line I.

[0093] Furthermore, the phase-shift layer prevents further etching by setting the sum of the silicon-nitrogen ratio within the aforementioned range. Because the phase-shift layer contains a high amount of silicon, the sum of the silicon-nitrogen ratio is within the aforementioned range, and no oxygen is added, it suppresses defects while improving transmittance.

[0094] Therefore, a higher chemical resistance and a shorter etching time can be achieved in the phase-shift layer.

[0095] In the phase shift mask blank according to one embodiment of the present invention, in the phase shift layer, an average value of a ratio O / Si of an oxygen composition ratio (atm %) to a silicon composition ratio (atm %) detected by Auger electron spectroscopy may be within a range of 0.01 to 0.15.

[0096] In this structure, the phase-shift layer has a detected oxygen-to-silicon ratio within the aforementioned range and no oxygen is added, thereby improving chemical resistance. While the absence of oxygen in the phase-shift layer naturally increases etching time, maintaining the detected oxygen-to-silicon ratio within the aforementioned range shortens etching time. Since the phase-shift layer contains nitrogen and no oxygen is added, its transmittance is increased, reaching approximately 5% under line I.

[0097] Furthermore, the phase-shift layer prevents further etching by maintaining the detected oxygen-to-silicon ratio within the aforementioned range. Because the phase-shift layer contains a high amount of silicon, the detected oxygen-to-silicon ratio is within the aforementioned range, and no oxygen is added, the generation of defects is suppressed while improving transmittance.

[0098] Therefore, a higher chemical resistance and a shorter etching time can be achieved in the phase-shift layer.

[0099] In the analysis using Auger electron spectroscopy, oxygen is detected, presumably due to the sample atmosphere, deposits such as moisture adhering to the sample, impurities mixed in during analysis, and the like.

[0100] A method for manufacturing a phase shift mask blank according to one embodiment of the present invention manufactures the phase shift mask blank according to the above embodiment. In this method, when forming the phase shift layer, sputtering is performed using a target having a composition in which the ratio of molybdenum to silicon is set to 7.0≤Si / Mo≤15.0.

[0101] In the above structure, by using the above target, a phase shift layer can be formed in which the average value of the ratio Si / Mo of the silicon composition ratio (atm%) to the molybdenum composition ratio (atm%) is within a range of 2.2 to 3.2.

[0102] In the method for manufacturing a phase shift mask blank according to one aspect of the present invention, when forming the phase shift layer, sputtering may be performed while supplying argon gas and nitrogen gas.

[0103] In the above configuration, by setting the gas supplied during the formation of the phase-shift layer as described above, a phase-shift layer having the following ranges can be formed. Specifically, the gas comprises nitrogen, molybdenum, and silicon, wherein the average value of the ratio of the silicon composition ratio (atm%) to the molybdenum composition ratio (atm%), Si / Mo, is within a range of 2.2 to 3.2. The average value of the ratio of the nitrogen composition ratio (atm%) to the silicon composition ratio (atm%), N / Si, is within a range of 0.50 to 0.65. The average value of the ratio of the silicon composition ratio (atm%) to the sum of the molybdenum composition ratio (atm%) and the nitrogen composition ratio (atm%), Si / (Mo+N), is within a range of 1.00 to 1.13. The average value of the ratio of the nitrogen composition ratio (atm%) to the sum of the molybdenum composition ratio (atm%) and the silicon composition ratio (atm%), N / (Mo+Si), is within a range of 0.35 to 0.50. The average value of the ratio of the nitrogen composition ratio (atm%) to the molybdenum composition ratio (atm%), N / Mo, is within a range of 1.4 to 1.75. The average value of the sum of the molybdenum composition ratio (atm%), the silicon composition ratio (atm%), and the nitrogen composition ratio (atm%) is within a range of greater than 90. The average value of the ratio of the oxygen composition ratio (atm%) to the silicon composition ratio (atm%), O / Si, detected by Auger electron spectroscopy, is within a range of 0.01 to 0.15.

[0104] A phase shift mask manufacturing method according to one aspect of the present invention uses a phase shift mask blank manufactured by the phase shift mask blank manufacturing method according to the above aspect, and patterns the phase shift mask blank by wet etching to manufacture a phase shift mask.

[0105] In the above configuration, a phase shift mask blank having a phase shift layer that can achieve both high chemical resistance and short etching time is used. Therefore, a high-quality phase shift mask can be manufactured by accurately forming a pattern and reducing damage to the transparent substrate.

[0106] A phase shift mask according to one aspect of the present invention is manufactured by the method for manufacturing a phase shift mask according to the above aspect.

[0107] According to the present invention, a phase shift mask blank having a phase shift layer that can achieve both high chemical resistance and short etching time can be provided, thereby achieving both reduction in surface roughness and defects of a glass substrate and simultaneously achieving patterning accuracy and maintenance of optical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0108] Figure 1 It is a cross-sectional view showing a phase shift mask blank according to an embodiment of the present invention.

[0109] Figure 2 It is a cross-sectional view showing a method for manufacturing a phase shift mask blank according to an embodiment of the present invention.

[0110] Figure 3 These are cross-sectional views showing the steps of a method for manufacturing a phase shift mask according to an embodiment of the present invention.

[0111] Figure 4 These are cross-sectional views showing the steps of a method for manufacturing a phase shift mask according to an embodiment of the present invention.

[0112] Figure 5 These are cross-sectional views showing the steps of a method for manufacturing a phase shift mask according to an embodiment of the present invention.

[0113] Figure 6 These are cross-sectional views showing the steps of a method for manufacturing a phase shift mask according to an embodiment of the present invention.

[0114] Figure 7 These are cross-sectional views showing the steps of a method for manufacturing a phase shift mask according to an embodiment of the present invention.

[0115] Figure 8 These are cross-sectional views showing the steps of a method for manufacturing a phase shift mask according to an embodiment of the present invention.

[0116] Figure 9 It is a cross-sectional view showing a phase shift mask according to an embodiment of the present invention.

[0117] Figure 10 It is a schematic diagram showing a film forming apparatus in a first embodiment of a method for manufacturing a phase shift mask blank according to an embodiment of the present invention.

[0118] Figure 11 It is a schematic diagram showing a film forming apparatus in a first embodiment of a method for manufacturing a phase shift mask blank according to an embodiment of the present invention.

[0119] Figure 12 Graph showing the results of Auger analysis of N in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0120] Figure 13 Graph showing the results of Auger analysis of O in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0121] Figure 14 This is a graph showing the results of Auger analysis of Si in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0122] Figure 15 This is a graph showing the results of Auger analysis of Mo in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0123] Figure 16This is a graph showing the results of Auger analysis of Si / Mo in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0124] Figure 17 This is a graph showing the results of Auger analysis of Si / (Mo+N) in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0125] Figure 18 This is a graph showing the results of Auger analysis of N / (Mo+Si) in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0126] Figure 19 This is a graph showing the results of Auger analysis of N / Mo in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0127] Figure 20 This is a graph showing the results of Auger analysis of O / Si in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0128] Figure 21 This is a graph showing the results of Auger analysis of O / Mo in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0129] Figure 22 This is a graph showing the results of Auger analysis of O / N in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0130] Figure 23 This is a graph showing the results of Auger analysis of (O+N) / Si in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0131] Figure 24 This is a graph showing the results of Auger analysis of Mo+Si+N in the phase shift layer in the experimental example according to the embodiment of the present invention.

[0132] Figure 25 The data show the results of Auger analysis of the phase shift layer in the experimental example according to the embodiment of the present invention.

[0133] Figure 26 The data show the change in transmittance of the phase shift layer in the experimental example according to the embodiment of the present invention. DETAILED DESCRIPTION

[0134] Hereinafter, a phase shift mask blank, a method for manufacturing a dependent mask blank, a phase shift mask, and a method for manufacturing a phase shift mask according to embodiments of the present invention will be described with reference to the accompanying drawings.

[0135] Figure 1 1 is a cross-sectional view showing a phase shift mask blank in this embodiment. Figure 210B is a cross-sectional view showing a method for manufacturing a phase shift mask blank in this embodiment.

[0136] The phase shift mask blank 10B according to the present embodiment is provided to a phase shift mask (photomask) used when the wavelength of exposure light is in the range of approximately 365 nm to 436 nm or the wavelength of exposure light is in the range of approximately 290 nm to 380 nm.

[0137] like Figure 1 As shown, the phase shift mask blank 10B according to the present embodiment includes a glass substrate 11 (transparent substrate), a phase shift layer 12 formed on the glass substrate 11 , and a light shielding layer 13 formed on the phase shift layer 12 .

[0138] The phase shift layer 12 is formed directly on the surface of the glass substrate 11. The light shielding layer 13 is provided at a position farther from the glass substrate 11 than the phase shift layer 12. The light shielding layer 13 is formed on the surface of the phase shift layer 12. The phase shift layer 12 is interposed between the glass substrate 11 and the light shielding layer 13.

[0139] The phase shift layer 12 and the light shielding layer 13 have optical properties required for a photomask and constitute a mask layer, which is a phase shift film that can change the phase of exposure light by approximately 180 degrees.

[0140] like Figure 2 As shown, the mask blank 10B according to the present embodiment may have a structure in which a photoresist layer 15 is formed in advance.

[0141] It should be noted that the phase-shift mask blank 10B according to this embodiment may have a structure in which the mask layer further includes an antireflection layer, an adhesion layer, a chemical-resistant layer, a protective layer, an etch-stop layer, and the like, in addition to the phase-shift layer 12 and the light-shielding layer 13. Furthermore, in the phase-shift mask blank 10B according to this embodiment, a photoresist layer 15 may be formed on the laminated film having such a structure.

[0142] The glass substrate 11 is made of a material having excellent transparency and optical isotropy. For example, a quartz glass substrate is used. The size of the glass substrate 11 is not limited. The size of the glass substrate 11 is appropriately selected to suit the substrate to be exposed using a phase-shift mask. Examples of substrates exposed using a phase-shift mask include substrates for FPDs such as LCDs (liquid crystal displays), plasma displays, and organic EL (electroluminescence) displays.

[0143] As the glass substrate 11, a rectangular substrate with a side of approximately 100 mm can be used. A side of the glass substrate 11 may be greater than 100 mm. A rectangular substrate with a side of 2000 mm or greater can be used for the glass substrate 11. A substrate with a thickness of 1 mm or less can be used for the glass substrate 11. A thickness of the glass substrate 11 may be greater than 1 mm. A substrate with a thickness of several millimeters can be used for the glass substrate 11. A substrate with a thickness of 10 mm or greater can also be used for the glass substrate 11.

[0144] Furthermore, the surface flatness of the glass substrate 11 can be reduced. This flatness can be reduced by polishing the surface of the glass substrate 11. The flatness of the glass substrate 11 can be, for example, 20 μm or less. Reducing the surface flatness of the glass substrate 11 increases the depth of focus of the mask. Reducing the surface flatness of the glass substrate 11 significantly contributes to the formation of fine, high-precision patterns. Furthermore, the surface flatness of the glass substrate 11 can be set to 10 μm or less. It is preferable to set the surface flatness of the glass substrate 11 to a relatively low value.

[0145] The phase shift layer 12 is a metal silicide film. The phase shift layer 12 is a film including silicon and a metal such as Ta, Ti, W, Mo, or Zr, or an alloy thereof.

[0146] The phase shift layer 12 is a molybdenum silicide film. The phase shift layer 12 contains O (oxygen). The phase shift layer 12 contains N (nitrogen). The phase shift layer 12 contains C (carbon). The phase shift layer 12 is MoSi X (X≥2) film. The phase shift layer 12 is a MoSi2 film. The phase shift layer 12 is a MoSi3 film. The phase shift layer 12 is a MoSi4 film.

[0147] The phase-shift layer 12 has predetermined optical properties. The phase-shift layer 12 must possess the optical properties necessary for use as a phase-shift mask. Therefore, the composition and thickness of the phase-shift layer 12 are set within predetermined ranges. For example, the phase-shift layer 12 is set to have a transmittance of approximately 5% at a wavelength of approximately 365 nm. Alternatively, the phase-shift layer 12 may be set to have a refractive index of approximately 2.4 to 3.1 within a wavelength range of approximately 365 nm to 436 nm, an extinction coefficient of 0.3 to 2.1, or the like. The optical properties of the phase-shift layer 12 are not limited to the values ​​described above.

[0148] The composition ratio and film thickness of the phase shift layer 12 are set according to the optical characteristics required for the phase shift mask 10 to be manufactured.

[0149] The phase shift layer 12 is a molybdenum silicide film containing N (nitrogen). The phase shift layer 12 preferably does not contain O (oxygen) or C (carbon). The phase shift layer 12 is a MoSiN film.

[0150] The silicon composition ratio in the phase-shift layer 12 is greater than the molybdenum composition ratio and the nitrogen composition ratio. The molybdenum composition ratio and the nitrogen composition ratio in the phase-shift layer 12 are approximately equal. The phase-shift layer 12 may contain impurities in addition to silicon, molybdenum, and nitrogen. The composition ratio of impurities other than silicon, molybdenum, and nitrogen in the phase-shift layer 12 is less than 10 atm%.

[0151] The composition ratio (atm %) of nitrogen constituting the phase shift layer 12 is within a range of 25 atm % to 30 atm %.

[0152] The composition ratio (atm%) of silicon constituting the phase shift layer 12 is within a range of 45 atm% to 50 atm%.

[0153] The composition ratio (atm%) of molybdenum constituting the phase shift layer 12 is within a range of 15 atm% to 20 atm%.

[0154] In the phase shift layer 12 , the average value of the ratio Si / Mo of the composition ratio (atm %) of silicon to the composition ratio (atm %) of molybdenum is within a range of 2.2 to 3.2.

[0155] In the phase shift layer 12 , an average value of the ratio N / Si of the composition ratio (atm %) of nitrogen to the composition ratio (atm %) of silicon is within a range of 0.50 to 0.65.

[0156] In the phase shift layer 12 , the average value of the ratio Si / (Mo+N) of the silicon composition ratio (atm%) to the sum of the molybdenum composition ratio (atm%) and the nitrogen composition ratio (atm%) is within a range of 1.00 to 1.13.

[0157] In the phase shift layer 12 , an average value of the ratio N / (Mo+Si) of the nitrogen composition ratio (atm%) to the sum of the molybdenum composition ratio (atm%) and the silicon composition ratio (atm%) is within a range of 0.35 to 0.50.

[0158] In the phase shift layer 12 , an average value of the ratio N / Mo of the composition ratio (atm %) of nitrogen to the composition ratio (atm %) of molybdenum is within a range of 1.4 to 1.75.

[0159] In the phase shift layer 12 , an average value of the sum of the composition ratio (atm%) of molybdenum, the composition ratio (atm%) of silicon, and the composition ratio (atm%) of nitrogen is within a range exceeding 90.

[0160] Here, the average value of each ratio is the value of the composition ratio after excluding measurement variations in the region where the composition ratio value is constant in the film thickness direction in the graph, as described later. Specifically, the arithmetic average can be calculated by excluding the maximum and minimum values ​​from a plurality of measured values ​​in the region corresponding to the phase shift layer 12. Alternatively, the arithmetic average can be calculated by excluding the maximum and next-largest values, and the minimum and next-smallest values ​​from the plurality of measured values. Alternatively, the arithmetic average can be calculated by excluding the maximum, a predetermined number of values ​​larger than the maximum, the minimum, and a predetermined number of values ​​smaller than the minimum, from the plurality of measured values.

[0161] When the composition of the phase-shift layer 12 is measured using Auger electron spectroscopy, oxygen and carbon, which were not added during film formation, are detected, as described below. While the reasons for this remain largely unclear, this indicates that oxygen and carbon are detected as unavoidable impurities during composition measurement using Auger electron spectroscopy. The detection of oxygen and carbon as unavoidable impurities is believed to occur due to the following factors: inclusion in the molybdenum silicide film due to incomplete removal in the film formation equipment, adhesion after film formation, or incorporation after film formation; or detection due to external factors such as incomplete removal before measurement and incorporation into the measurement atmosphere.

[0162] In the phase shift layer 12 , the composition ratio (atm %) of oxygen detected by Auger electron spectroscopy is within a range of 0 atm % to 5 atm %.

[0163] In the phase shift layer 12 , the average value of the ratio O / Si of the composition ratio (atm %) of oxygen to the composition ratio (atm %) of silicon detected by Auger electron spectroscopy is within a range of 0.01 to 0.15.

[0164] In the phase shift layer 12 , the average value of the ratio O / N of the composition ratio (atm %) of oxygen to the composition ratio (atm %) of nitrogen detected by Auger electron spectroscopy is within a range of 0.01 to 0.3.

[0165] In the phase shift layer 12 , the average value of the ratio O / Mo of the composition ratio (atm %) of oxygen to the composition ratio (atm %) of molybdenum detected by Auger electron spectroscopy is within a range of 0.01 to 0.3.

[0166] In the phase shift layer 12 , the average value of the ratio (O+N) / Si of the oxygen composition ratio (atm%) and the nitrogen composition ratio (atm%) to the silicon composition ratio (atm%) detected by Auger electron spectroscopy is within a range of 0.6 to 0.75.

[0167] The phase shift layer 12 contains impurities other than nitrogen, silicon, molybdenum, and oxygen detected by Auger electron spectroscopy. The composition ratio (atm%) of the impurities in the phase shift layer 12 is in the range of 0 atm% to 5 atm%. Specifically, the impurities may be carbon (C).

[0168] In the phase shift layer 12 , the composition ratio (atm%) of the impurities is almost equal to the composition ratio (atm%) of oxygen detected by Auger electron spectroscopy, or is slightly smaller than the composition ratio (atm%) of oxygen, and is within the range of 0.54 to 0.55.

[0169] The phase shift layer 12 may have a composition that varies in the thickness direction. For example, the composition of the phase shift layer 12 may vary from the glass substrate 11 toward the light shielding layer 13 in the thickness direction.

[0170] The film thickness of the phase shift layer 12 is set within a range of 100 nm to 200 nm. The film thickness of the phase shift layer 12 is set within a range of 120 nm to 150 nm. The film thickness of the phase shift layer 12 is set within a range of 135 nm to 145 nm.

[0171] The light shielding layer 13 contains Cr (chromium) as a main component. The light shielding layer 13 contains O (oxygen) as a main component. The light shielding layer 13 contains C (carbon). The light shielding layer 13 contains N (nitrogen).

[0172] The light shielding layer 13 may also be formed by laminating one or two or more substances selected from chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium carbonitride, and chromium oxycarbonitride.

[0173] The light shielding layer 13 contains Cr (chromium) and O (oxygen) as main components. The light shielding layer 13 may further contain C (carbon) and N (nitrogen).

[0174] In this case, the light-shielding layer 13 can also be formed by laminating one or more materials selected from Cr oxides, nitrides, carbides, oxynitrides, carbonitrides, and oxycarbonitrides. Furthermore, the light-shielding layer 13 can have a composition that varies across the thickness. For example, the light-shielding layer 13 can have a composition in which the nitrogen concentration or oxygen concentration varies across the thickness. In other words, the light-shielding layer 13 can have a concentration gradient across the thickness.

[0175] Furthermore, the light-shielding layer 13 may have a composition that varies across its thickness. For example, the nitrogen concentration of the light-shielding layer 13 may vary across its thickness. The oxygen concentration of the light-shielding layer 13 may vary across its thickness. The carbon concentration of the light-shielding layer 13 may vary across its thickness. In this way, the light-shielding layer 13 may have a concentration gradient across its thickness.

[0176] The thickness of the light shielding layer 13 and the composition ratio (atm %) of Cr, N, C, O, Si, etc. are set so that the light shielding layer 13 can obtain predetermined adhesion (hydrophobicity) and predetermined optical characteristics as described later.

[0177] The concentrations (composition ratios, atm %) of chromium, nitrogen, carbon, oxygen, and the like in the light-shielding layer 13 are set so that the light-shielding layer 13 obtains predetermined optical properties. The film thickness of the light-shielding layer 13 is set so that the light-shielding layer 13 obtains predetermined optical properties. The film properties of the light-shielding layer 13 vary depending on the composition ratios of chromium, nitrogen, carbon, oxygen, and the like. The film thickness of the light-shielding layer 13 can be set, in particular, based on the optical properties required for the phase-shift mask 10.

[0178] By setting the film thickness and composition of the light-shielding layer 13 as described above, the adhesion between the photoresist layer 15, for example, for a chromium-based material, and the light-shielding layer 13 is improved during the patterning process using photolithography. Furthermore, by setting the film thickness and composition as described above, the etching solution does not penetrate into the interface between the photoresist layer 15 and the light-shielding layer 13. Therefore, a good pattern shape can be obtained, and a desired pattern can be formed.

[0179] If the light-shielding layer 13 is not set to the above conditions, etching during mask pattern formation may cause defects at the interface between the phase-shift layer 12 and the light-shielding layer 13, which is undesirable. If the light-shielding layer 13 is not set to the above conditions, a mask pattern with a non-vertical cross-sectional shape may be formed, which is undesirable. Furthermore, if the light-shielding layer 13 is not set to the above conditions, it is difficult to achieve the desired optical properties as a photomask, which is undesirable.

[0180] In the light-shielding layer 13, the refractive index can be lowered by increasing the oxygen concentration in the chromium compound. In the light-shielding layer 13, the extinction coefficient can be lowered by increasing the oxygen concentration in the chromium compound. In the light-shielding layer 13, the refractive index can be lowered by increasing the nitrogen concentration in the chromium compound. In the light-shielding layer 13, the extinction coefficient can be lowered by increasing the nitrogen concentration in the chromium compound.

[0181] In the light-shielding layer 13, the refractive index can be increased by reducing the oxygen concentration in the chromium compound. In the light-shielding layer 13, the extinction coefficient can be increased by reducing the oxygen concentration in the chromium compound. In the light-shielding layer 13, the refractive index can be increased by reducing the nitrogen concentration in the chromium compound. In the light-shielding layer 13, the extinction coefficient can be increased by reducing the nitrogen concentration in the chromium compound.

[0182] In the phase-shift mask blank 10B of this embodiment, the phase-shift layer 12 improves chemical resistance. It also shortens etching time. The transmittance of the phase-shift layer 12 can be set to approximately 5% under line I. The phase-shift layer 12 prevents further etching. The phase-shift layer 12 suppresses defects while improving transmittance.

[0183] The phase-shift layer 12 can achieve both high chemical resistance and short etching time.

[0184] Next, a method for manufacturing a phase shift mask blank according to the present embodiment will be described with reference to the drawings.

[0185] Figure 3 It is a cross-sectional view showing the manufacturing process of the phase shift mask blank and the phase shift mask according to this embodiment. Figure 4 The diagram shows cross-sectional views of the manufacturing steps of the phase shift mask blank and the phase shift mask according to the present embodiment. Figure 5 It is a cross-sectional view showing the manufacturing process of the phase shift mask blank and the phase shift mask according to this embodiment. Figure 6 It is a cross-sectional view showing the manufacturing process of the phase shift mask blank and the phase shift mask according to the present embodiment. Figure 7 It is a cross-sectional view showing the manufacturing process of the phase shift mask blank and the phase shift mask according to the present embodiment. Figure 8 It is a cross-sectional view showing the manufacturing process of the phase shift mask blank and the phase shift mask according to this embodiment. Figure 9 3 is a cross-sectional view showing a phase shift mask according to this embodiment. Figure 10 It is a schematic diagram showing a manufacturing apparatus for a phase shift mask blank according to this embodiment.

[0186] The method for manufacturing a phase shift mask blank of the present embodiment includes a film forming step of forming a mask layer on a glass substrate 11. In the film forming step, after the phase shift layer 12 is formed on the glass substrate 11, the light shielding layer 13 is formed.

[0187] The phase shift mask blank 10B of this embodiment is composed of Figure 10 The manufacturing apparatus (film forming apparatus) shown is manufactured in S10.

[0188] like Figure 10 As shown, the manufacturing apparatus S10 is a reciprocating sputtering apparatus and includes a loading chamber S11, an unloading chamber S16, and a film forming chamber (vacuum processing chamber) S12.

[0189] The loading chamber S11 includes a conveying mechanism S11a and an exhaust mechanism S11f. The conveying mechanism S11a transports the glass substrate 11 brought in from outside the manufacturing apparatus S10 to the film forming chamber S12. The exhaust mechanism S11f roughly depressurizes the interior of the loading chamber S11. The exhaust mechanism S11f is, for example, a rotary pump. The loading chamber S11 is connected to the film forming chamber S12 via a sealing mechanism S17.

[0190] The unloading chamber S16 includes a conveying mechanism S16a and an exhaust mechanism S16f. The conveying mechanism S16a unloads the film-formed glass substrate 11 from the film-forming chamber S12. The exhaust mechanism S16f roughly depressurizes the interior of the unloading chamber S16. The exhaust mechanism S16f is a rotary pump or the like. The unloading chamber S16 is connected to the film-forming chamber S12 via a sealing mechanism S18.

[0191] The film forming chamber S12 includes a substrate holding mechanism S12a, a film forming mechanism S13, a film forming mechanism S14, and a gas barrier S12g. The film forming chamber S12 includes two film forming mechanisms, the film forming mechanism S13 and the film forming mechanism S14. The film forming chamber S12 includes a mechanism corresponding to a two-stage film forming process.

[0192] The substrate holding mechanism S12a receives the glass substrate 11 conveyed by the conveying mechanism S11a. The substrate holding mechanism S12a holds the glass substrate 11 within the film forming chamber S12. The substrate holding mechanism S12a holds the glass substrate 11 so that it faces the target S13b of the film forming mechanism S13 and the target S14b of the film forming mechanism S14 during film formation. The substrate holding mechanism S12a conveys the glass substrate 11 within the film forming chamber S12. The substrate holding mechanism S12a then transfers the glass substrate 11 to the conveying mechanism S16a.

[0193] The substrate holding mechanism S12a can apply bias power to the glass substrate 11 during film formation. The substrate holding mechanism S12a can set the temperature of the glass substrate 11 during film formation.

[0194] The film-forming mechanism S13 is located within the film-forming chamber S12, near the loading chamber S11. The film-forming mechanism S13 performs the first-stage film-forming process of the two-stage film-forming process. The film-forming mechanism S13 supplies the film-forming material for the first-stage film-forming process to the space between the target S13b and the transparent substrate 11. In the following description, the space between the target S13b and the transparent substrate 11, or the space between the target S14b and the transparent substrate 11, may be referred to as the film-forming space.

[0195] The film forming mechanism S13 includes a target S13b, a cathode electrode (backing plate) S13c, a power supply S13d, a gas introduction mechanism S13e, and a high vacuum exhaust mechanism S13f.

[0196] The target S13b supplies the first-stage film-forming material to the film-forming space. The target S13b is mounted on the cathode electrode S13c. The power supply S13d applies a sputtering voltage of a negative potential to the backing plate S13c.

[0197] The gas introduction mechanism S13e introduces the first-stage film-forming gas into the film-forming chamber S12. The gas introduction mechanism S13e introduces the first-stage film-forming gas into the film-forming mechanism S13. The gas introduction mechanism S13e primarily introduces the film-forming gas toward the area near the cathode electrode S13c. The high-vacuum exhaust mechanism S13f depressurizes the interior of the film-forming chamber S12. The high-vacuum exhaust mechanism S13f primarily depressurizes the area near the cathode electrode S13c to achieve a higher vacuum level. The high-vacuum exhaust mechanism S13f utilizes a turbomolecular pump, for example.

[0198] The film forming mechanism S13 may include a magnetron magnetic circuit that forms a predetermined magnetic field on the target S13b.

[0199] The film forming mechanism S14 is arranged in the film forming chamber S12 at a position close to the unloading chamber S16. The film forming mechanism S14 performs the second-stage film forming process of the two-stage film forming process and supplies the film forming material for the second-stage film forming process to the film forming space.

[0200] The film forming mechanism S14 has a structure corresponding to the second-stage film forming process and has a structure equivalent to that of the film forming mechanism S13.

[0201] The film forming mechanism S13 and the film forming mechanism S14 are adjacent to each other inside the film forming chamber S12.

[0202] The gas-proof wall S12g is arranged inside the film-forming chamber S12. The gas-proof wall S12g is arranged between the film-forming mechanism S13 and the film-forming mechanism S14. The gas-proof wall S12g isolates the film-forming gas in the film-forming mechanism S13 and the film-forming mechanism S14. The gas-proof wall S12g is arranged in the film-forming mechanism S13 and the film-forming mechanism S14 to avoid mixing of the film-forming gases. The gas-proof wall S12g suppresses the flow of the film-forming gas between the film-forming mechanism S13 and the film-forming mechanism S14. The gas-proof wall S12g is constructed so that the substrate holding mechanism S12a can move between the film-forming mechanism S13 and the film-forming mechanism S14.

[0203] Film-forming mechanisms S13 and S14 have the necessary structures for performing two-stage film-forming processes. They can implement the conditions required for performing two-stage film-forming processes. Film-forming mechanism S13 forms the phase shift layer 12 , while film-forming mechanism S14 forms the light-shielding layer 13 .

[0204] The target S13b of the film forming mechanism S13 has a composition required for forming the phase shift layer 12. The material of the target S13b is molybdenum silicide.

[0205] The gas introduction mechanism S13e of the film formation mechanism S13 supplies process gas and sputtering gas required for forming the phase shift layer 12 into the film formation space. The gas introduction mechanism S13e can supply argon gas and nitrogen gas. The gas introduction mechanism S13e does not supply oxygen-containing gas or carbon-containing gas.

[0206] The gas introduction mechanism S13e and the high vacuum exhaust mechanism S13f set the gas partial pressure required for forming the phase shift layer 12. The gas introduction mechanism S13e and the high vacuum exhaust mechanism S13f can change the gas supply conditions in the thickness direction of the phase shift layer 12. The gas introduction mechanism S13e and the high vacuum exhaust mechanism S13f set the conditions required for forming the etching time reduction layer 12a, the intermediate layer 12b, and the surface layer, respectively.

[0207] The power supply S13d of the film forming mechanism S13 sets the sputtering voltage according to the film formation of the phase shift layer 12. The power supply S13d sets the conditions required for forming the etching time shortening layer 12a, the intermediate layer 12b, and the surface layer.

[0208] The target S14b of the film forming mechanism S14 has a composition required for forming the light shielding layer 13. The material of the target S14b contains chromium.

[0209] The gas introduction mechanism S14e of the film forming mechanism S14 supplies the gas required for forming the light shielding layer 13 into the film forming space. The gas introduction mechanism S14e can supply process gas containing carbon, nitrogen, oxygen, etc. The gas introduction mechanism S14e can supply sputtering gas such as argon and nitrogen.

[0210] The gas introduction mechanism S14e and the high vacuum exhaust mechanism S14f set the gas partial pressure required for forming the light shielding layer 13. The gas introduction mechanism S14e and the high vacuum exhaust mechanism S14f can change the supply gas conditions in the thickness direction of the light shielding layer 13.

[0211] The power supply S14 d of the film forming mechanism S14 sets a sputtering voltage according to the film forming of the light shielding layer 13 .

[0212] When the phase shift mask blank 10B is manufactured in the manufacturing apparatus S10 , the glass substrate 11 is carried into the loading chamber S11 as a preparatory step.

[0213] The glass substrate 11 is transported from the loading chamber S11 to the film forming chamber S12 by a transport mechanism S11a. The glass substrate 11 is transported within the film forming chamber S12 by a substrate holding mechanism S12a. Two-stage sputtering film formation is performed on the glass substrate 11 within the film forming chamber S12 as a film forming process. After film formation, the glass substrate 11 is transported from the film forming chamber S12 to the unloading chamber S16 by the substrate holding mechanism S12a. The glass substrate 11 is unloaded to the outside by a transport mechanism S16a.

[0214] The film forming process includes a phase shift layer forming process and a light shielding layer forming process.

[0215] In the phase shift layer forming step, the phase shift layer 12 is formed on the glass substrate 11. The phase shift layer forming step is performed in the film forming mechanism S13.

[0216] During the phase-shift layer formation step, the film-forming mechanism S13 supplies process gas and sputtering gas into the film-forming space via a gas introduction mechanism S13e. During the phase-shift layer formation step, a sputtering voltage is applied to the film-forming mechanism S13 via a power supply S13d. During the phase-shift layer formation step, a magnetron magnetic circuit generates a predetermined magnetic field on the target S13b.

[0217] During the phase-shift layer formation process, the film-forming unit S13 generates plasma in an area near the target S13b. The plasma excites ions in the sputtering gas. These ions collide with the target S13b, scattering particles of the film-forming material. The particles of film-forming material scattered from the target S13b combine with the reactive gas and adhere to the glass substrate 11. This forms the phase-shift layer 12 on the surface of the glass substrate 11.

[0218] During the phase-shift layer formation process, a gas introduction mechanism S13e supplies gases into the film-forming space. The supplied gases are Ar gas and N2 gas (nitrogen). This forms a film composed of nitrogen, molybdenum, and silicon. The gas introduction mechanism S13e supplies each gas into the film-forming space at a specified partial pressure as the film thickness increases. Furthermore, the gas introduction mechanism S13e can control the partial pressure of each gas as the film thickness increases. In this case, during the phase-shift layer formation process, the composition of the phase-shift layer 12 can be set within a concentration range that varies across the film thickness by controlling the gas partial pressures.

[0219] In the phase shift layer forming step, the film forming atmosphere of the phase shift layer 12 can be set to a low pressure of 1.0 Pa or less, about 0.1 to 0.5 Pa, preferably about 0.1 to 0.3 Pa, about 0.2 Pa.

[0220] In the phase shift layer forming step, sputtering is performed using a target material having a composition set such that the ratio of molybdenum to silicon satisfies 7.0≤Si / Mo≤15.0. In particular, a target material having a silicon content approximately 9.0 times greater than molybdenum can be used.

[0221] In the phase shift layer forming step, the plasma generation power applied by the power supply S13d to the cathode electrode S13c is set to a predetermined range.

[0222] In the phase shift layer forming step, the substrate holding mechanism S12 a may apply bias power to the glass substrate 11 .

[0223] Furthermore, during the phase-shift layer formation step, the temperature of the glass substrate 11 supported by the substrate holding mechanism S12a is maintained at a low temperature. Specifically, during the phase-shift layer formation step, the temperature of the glass substrate 11 can be set to below 100°C, below 50°C, or around room temperature. In this case, the substrate holding mechanism S12a does not need to actively heat the glass substrate 11. The substrate holding mechanism S12a can cool the glass substrate 11.

[0224] In the light shielding layer forming step, the light shielding layer 13 is formed on the glass substrate 11. In the light shielding layer forming step, the light shielding layer 13 is stacked on the phase shift layer 12. The light shielding layer forming step is performed in the film forming mechanism S14.

[0225] During the light-shielding layer formation step, the film-forming mechanism S14 supplies process gas and sputtering gas to the film-forming space via a gas introduction mechanism S14e. During the light-shielding layer formation step, a sputtering voltage is applied to the film-forming mechanism S14 via a power supply 14d. During the light-shielding layer formation step, a magnetron magnetic circuit can generate a predetermined magnetic field on the target S14b.

[0226] During the light-shielding layer formation process, the film-forming unit S14 generates plasma in an area near the target S14b. The plasma excites ions in the sputtering gas. The sputtering gas ions collide with the target S14b, scattering particles of the film-forming material. The particles of film-forming material scattered from the target S14b combine with the reactive gas and adhere to the surface of the phase-shift layer 12. This forms the light-shielding layer 13 on the surface of the phase-shift layer 12.

[0227] In the light shielding layer forming step, a target material S14b containing chromium is used. In the light shielding layer forming step, a target material S14b made of chromium is used. During the film formation of the light shielding layer 13, the target material S14b can be replaced as needed.

[0228] In the light shielding layer forming step, the plasma generating power applied by the power supply S14d to the cathode electrode S14c is set to a predetermined range.

[0229] In the light shielding layer forming step, the substrate holding mechanism S12 a may apply bias power to the glass substrate 11 .

[0230] In the light shielding layer forming step, the sputtering power applied by the power supply S14 d and the bias power applied by the substrate holding mechanism S12 a may be changed according to the film thickness of the light shielding layer 13 .

[0231] In the light-shielding layer forming process, the gas introduction mechanism S14e supplies gas to the film forming space. The supplied gas is sputtering gas, carbon-containing gas, nitrogen-containing gas, oxygen-containing gas, etc. The gas introduction mechanism S14e can supply each gas at a specified partial pressure as the film thickness increases. In addition, the gas introduction mechanism S14e can be switched in a manner that controls the partial pressure of each gas as the film thickness increases. Thus, in the light-shielding layer forming process, by controlling the gas partial pressure, the composition of the light-shielding layer 13 is set to a concentration range set in the film thickness direction.

[0232] During the light-shielding layer formation step, the composition of the light-shielding layer 13 can be varied in the film thickness direction. In this case, the partial pressures of the various gases in the atmosphere can be varied according to the thickness of the formed film. During the light-shielding layer formation step, the composition of the light-shielding layer 13 can be constant in the film thickness direction. In this case, the partial pressures of the various gases in the atmosphere can be maintained constant according to the thickness of the formed film.

[0233] Examples of oxygen-containing gases include CO2 (carbon dioxide), O2 (oxygen), N2O (nitrous oxide), NO (nitrogen monoxide), and CO (carbon monoxide). Examples of carbon-containing gases include CO2 (carbon dioxide), CH4 (methane), C2H6 (ethane), and CO (carbon monoxide). Examples of nitrogen-containing gases include N2 (nitrogen), N2O (nitrous oxide), NO (nitric oxide), and NH3 (ammonia).

[0234] The method for manufacturing a phase-shift mask blank may include steps other than the phase-shift layer forming step and the light-shielding layer forming step. For example, the method for manufacturing a phase-shift mask blank may include steps for forming an etch stop layer, a protective layer, an adhesion layer, a chemical-resistant layer, an anti-reflection layer, and the like. Thus, the phase-shift mask blank 10B may include an etch stop layer, a protective layer, an adhesion layer, a chemical-resistant layer, an anti-reflection layer, and the like.

[0235] When performing such steps, the sputtering conditions such as target material and gas corresponding to each step may be set to form a film by sputtering, or a film may be stacked by other film forming methods.

[0236] By the manufacturing method of the phase shift mask blank according to this embodiment, a Figure 1 Phase shift mask blank 10B is shown.

[0237] like Figure 9 As shown, the phase shift mask 10 (photomask) of this embodiment is manufactured by forming a pattern on a mask blank 10B having a phase shift layer 12 and a light shielding layer 13 .

[0238] Next, a method for manufacturing the phase shift mask 10 from the mask blank 10B according to the present embodiment will be described.

[0239] As a resist pattern forming process, Figure 2 As shown, a photoresist layer 15 is formed on the outermost surface of the phase shift mask blank 10B. Alternatively, a phase shift mask blank 10B having the photoresist layer 15 formed on the outermost surface can be prepared. The photoresist layer 15 can be either positive or negative. A so-called photoresist compatible with etching of chromium-based materials and molybdenum silicide-based materials is used as the photoresist layer 15. Liquid resist is also used as the photoresist layer 15.

[0240] Next, the photoresist layer 15 is exposed and developed to form a resist pattern 15P1 outside the light shielding layer 13. The resist pattern 15P1 functions as an etching mask for etching the phase shift layer 12 and the light shielding layer 13.

[0241] The shape of the resist pattern 15P1 is appropriately determined according to the etching pattern of the phase shift layer 12 and the light shielding layer 13. As an example, the shape of the resist pattern 15P1 is set to have an opening width that is equal to the width of the light-transmitting region 10L to be formed (see FIG. Figures 4 to 9 ) corresponds to the opening width dimension.

[0242] Next, as a light shielding pattern forming step, the light shielding layer 13 is wet-etched using an etching solution via the resist pattern 15P1, thereby forming a light shielding pattern. Figure 3 The light shielding pattern 13P1 is formed as shown.

[0243] As the etching solution in the light shielding pattern forming step, an etching solution for chromium-based materials is used. As the etching solution for chromium-based materials, an etching solution containing ammonium cerium nitrate can be used. For example, ammonium cerium nitrate containing an acid such as nitric acid or perchloric acid is preferably used.

[0244] Next, as a phase shift pattern forming step, the phase shift layer 12 is wet-etched using an etching solution via the light shielding pattern 13P1 and the resist pattern 15P1. Figure 4 Phase shift pattern 12P1 is formed as shown. An etchant capable of etching the phase shift layer 12 made of molybdenum silicide is used as the etchant in the phase shift pattern forming step. The etchant is preferably a solution containing at least one fluorine compound selected from hydrofluoric acid, hydrofluoric acid, and ammonium bifluoride, and at least one oxidizing agent selected from hydrogen peroxide, nitric acid, and sulfuric acid.

[0245] In this case, the phase-shift layer 12 having the above-described composition ratio can prevent the problem of a high etching rate (ER) for a molybdenum silicide-based etchant but a correspondingly long etching time. Furthermore, the etching rate (ER) for the molybdenum silicide-based etchant is low within the phase-shift layer 12, shortening the etching time for the entire phase-shift layer 12. Furthermore, the generation of defects within the phase-shift layer 12 is suppressed.

[0246] This can shorten the etching time and suppress the influence (over-etching) on ​​the glass substrate 11 affected by the etching liquid.

[0247] Therefore, if Figure 4 As shown, a light-transmitting region 10L can be formed to expose the surface of the glass substrate 11. After the light-shielding pattern 13P1 and the phase-shift pattern 12P1 are formed by etching, a good cross-sectional shape close to vertical can be obtained as the cross-sectional shape of the phase-shift mask 10.

[0248] After the phase shift pattern forming step is completed, a cleaning step is performed as needed. The cleaning step is a resist removal step. In the cleaning step, the resist pattern 15P1 is removed.

[0249] In the cleaning process, sodium hydroxide solution, potassium hydroxide solution, and tetramethylammonium hydroxide (TMAH) solution are used as cleaning solutions. The phase shift layer 12 has a high chemical resistance due to the above composition ratio, and the film thickness of the phase shift pattern 12P1 is not changed by the alkaline solution in the cleaning process.

[0250] As a resist pattern forming process, Figure 5 As shown, the photoresist layer 15 is exposed and developed. Figure 6 As shown in FIG. 1 , a resist pattern 15P2 is formed outside the light shielding pattern 13P1. The resist pattern 15P2 functions as an etching mask for etching the light shielding pattern 13P1.

[0251] The shape of the resist pattern 15P2 is appropriately determined according to the etching pattern of the light shielding pattern 13P1. As an example, the shape of the resist pattern 15P2 is set to have an opening width that is equal to the width of the exposure region 10P1 and the phase shift region 10P2 to be formed (see FIG. Figures 7 to 9 ) corresponds to the opening width dimension.

[0252] Next, as a light shielding pattern forming step, the light shielding pattern 13P1 is wet-etched using an etching solution via the resist pattern 15P2, thereby forming a light shielding pattern. Figure 7 The light shielding pattern 13P2 is formed as shown.

[0253] Thus, the light shielding pattern 13P2 corresponding to the exposure region 10P1 and the phase shift region 10P2 that expose the surface of the phase shift pattern 12P1 can be formed.

[0254] As the etching liquid in the light shielding pattern forming process, an etching liquid of a chromium-based material is also used. As such an etching liquid, an etching liquid containing ammonium cerium nitrate can be used. For example, ammonium cerium nitrate containing an acid such as nitric acid or perchloric acid is preferably used.

[0255] Next, as a phase shift pattern forming step, wet etching is performed through the phase shift pattern 12P1 using an etching solution via the resist pattern 15P2 and the light shielding pattern 13P2. Figure 8 A phase shift pattern 12P2 is formed as shown.

[0256] This can shorten the etching time and suppress the influence of the etching solution on the glass substrate 11 exposed in the light-transmitting region 10L.

[0257] Therefore, if Figure 8 As shown, an exposure region 10P1 exposing the surface of the glass substrate 11 and a phase shift region 10P2 exposing the remaining phase shift pattern 12P2 can be formed.

[0258] Next, as a resist removal step, the resist pattern 15P2 is removed. Figure 9 As shown, a phase-shift mask 10 is manufactured.

[0259] Next, the film characteristics of the phase shift layer 12 in this embodiment will be described.

[0260] The phase-shift mask blank 10B has a mask layer formed on a glass substrate 11. The mask layer is formed using a sputtering method or other methods. Regarding the mask layer, the phase-shift layer 12 is formed first. The phase-shift layer 12 is formed from a molybdenum silicide compound. The molybdenum silicide compound formed here is a film containing molybdenum, silicon, and nitrogen. The composition of the molybdenum, silicon, and nitrogen contained in the film and the film thickness corresponding to the composition are controlled. This allows the phase-shift layer 12 to have the desired transmittance, phase, etching rate, chemical resistance, and defect resistance.

[0261] After forming the phase shift layer 12, a chromium compound is formed to become the light shielding layer 13. Thus, the phase shift mask blank 10B for forming the phase shift mask 10 can be constructed.

[0262] The phase shift mask 10 is formed from this phase shift mask blank 10B.

[0263] The phase-shift mask 10 may be formed by performing resist pattern formation and etching of the phase-shift mask blank 10B formed.

[0264] As a result of intensive studies, the present inventors have clarified the following.

[0265] It is understood that in order to simultaneously improve chemical resistance and etching rate in the phase shift layer 12 to improve patterning accuracy, it is important to form the phase shift layer 12 from a molybdenum silicide film having a high silicon concentration (composition ratio) and to add only nitrogen.

[0266] This discovery revealed that a phase-shift layer 12 with a short etching time, high chemical resistance, and good defect quality can be formed by a method different from the conventional idea (i.e., controlling the film properties of the phase-shift layer by reducing the silicon concentration and then controlling the concentration (composition ratio) of oxygen, carbon, etc.).

[0267] When the phase shift layer 12 is formed of a molybdenum silicide film, etching with an etchant containing hydrofluoric acid is required when forming the phase shift mask 10. Therefore, in order to reduce the effect of etching on the glass substrate 11, it is preferable to use a molybdenum silicide film with the fastest possible etching rate.

[0268] By using a target material having a molybdenum to silicon ratio within the above-described range, the silicon concentration in the molybdenum silicide film is increased. This results in a high etching rate (ER) for the molybdenum silicide film. This allows for the formation of a molybdenum silicide film having an etching rate that suppresses etching of the glass substrate 11. This allows for the production of a phase shift mask blank 10B that reduces the impact of defects and is suitable for production.

[0269] When forming a molybdenum silicide film as the phase shift layer 12, a target having a composition ratio of molybdenum to silicon within the above range is used. When forming a molybdenum silicide film as the phase shift layer 12, the flow rates of argon and nitrogen during film formation are changed.

[0270] In the manufacturing process of the phase shift mask 10, a chemical solution such as an acid or an alkali is generally used when forming a pattern. In these processes, it is necessary to suppress changes in the phase shift angle, the film thickness, and the transmittance.

[0271] It is known that setting the nitrogen concentration of the molybdenum silicide film within the above range improves the resistance to acidic or alkaline chemical solutions. This shows that setting the nitrogen concentration range of the molybdenum silicide film is important to improve chemical solution resistance.

[0272] Furthermore, the oxygen and carbon concentrations in the molybdenum silicide film were measured while varying the gas conditions during the formation of the molybdenum silicide film. The relationship between the ratio of the oxygen concentration (O concentration) to the carbon concentration (C concentration) in the molybdenum silicide film and the etching rate was investigated. The results show that the etching rate in the molybdenum silicide film is increased by controlling the oxygen and carbon concentrations to extremely low levels. It is also shown that by reducing the oxygen and carbon concentrations in the molybdenum silicide film, defect generation can be suppressed to an extremely low level. Furthermore, it is shown that the chemical resistance of the molybdenum silicide film is enhanced.

[0273] Taking these results into consideration, the concentration distribution (composition ratio) in the phase shift layer 12 is set.

[0274] Specifically, as the phase shift layer 12, it is preferable that the ratios of molybdenum, silicon, and nitrogen are set to:

[0275] Mo=about 0.15~0.2

[0276] Si=0.45~0.50

[0277] N=about 0.25~0.30.

[0278] More preferably, it can be set as:

[0279] Mo=about 1

[0280] Si=2.6

[0281] N=about 1.6.

[0282] Furthermore, as the phase shift layer 12, the ratio of the remainder other than molybdenum, silicon, and nitrogen can be set to:

[0283] Mo=about 0.15~0.2

[0284] Si=0.45~0.50

[0285] N=0.25~0.30

[0286] Margin = approximately 0 to 0.10.

[0287] More preferably, it is:

[0288] Mo=around 18

[0289] Si=around 48

[0290] N=about 27

[0291] Margin = about 7.

[0292] As a phase shift mask used in a display, a phase shift mask 10 having a phase of 180° at a wavelength of 365 nm (I line) and a transmittance of 5% or more is used.

[0293] Next, embodiments of the present invention will be described.

[0294] <Experimental Example 1>

[0295] As Experimental Example 1, three layers of molybdenum silicide compound films were formed on a glass substrate by sputtering or the like as the phase shift layer 12. The molybdenum silicide compound films formed here were films containing molybdenum, silicon, and nitrogen.

[0296] Here, in the sputtering for forming the molybdenum silicide compound film, a target having a ratio of molybdenum to silicon of Mo:Si=1:9.0 was used.

[0297] The film was formed by adding only nitrogen (N2) to argon as the atmospheric gas during sputtering. The film formation pressure was set to 0.2 Pa. The substrate was not heated, and the film was formed while the substrate was moved relative to the target while maintaining room temperature (18°C to 25°C).

[0298] The film formation conditions of the phase shift layer are shown below.

[0299] Ar flow rate: 130 sccm

[0300] N2 flow rate: 45.5sccm

[0301] Film thickness: 130nm

[0302] Film forming atmosphere: 0.2Pa

[0303] Glass substrate temperature: 22.0°C

[0304] Glass substrate size: 850mm×1200mm

[0305] Furthermore, the composition of the phase shift layer 12 after film formation was evaluated using Auger electron spectroscopy. The results are shown in FIG. Figures 11 to 25 middle.

[0306] It should be explained that Figures 11 to 25 In the figure, the horizontal axis represents the etching time in Auger electron spectroscopy, which corresponds to the depth in the film thickness direction. In addition, Si, Mo, N, O, and C were detected.

[0307] <Experimental Example 2>

[0308] As Experimental Example 2, a molybdenum silicide compound film containing oxygen and carbon was formed on a glass substrate in the same manner as Experimental Example 1. In this case, a target having a molybdenum to silicon ratio of Mo:Si=1:2.3 was used for sputtering to form the molybdenum silicide compound film.

[0309] The film formation conditions of the phase shift layer are shown below.

[0310] Ar flow rate: 130 sccm

[0311] N2 flow rate: 98sccm

[0312] CO2 flow rate: 8.0 sccm

[0313] Film thickness: 130nm

[0314] Film forming atmosphere: 0.2Pa

[0315] Glass substrate temperature: 22.0°C

[0316] Glass substrate size: 850mm×1200mm

[0317] Furthermore, the composition of the formed molybdenum silicide compound film was evaluated by Auger electron spectroscopy in the same manner as in Experimental Example 1. The results are shown in FIG. Figures 11 to 25 middle.

[0318] from Figure 11 The results show that the average nitrogen composition ratio (atm%) N in the MoSiN film of Experimental Example 1 is in the range of 26 to 29. Furthermore, the average nitrogen composition ratio (atm%) N in the MoSiN film of Experimental Example 2 is in the range of 22 to 27.

[0319] from Figure 12 The results show that the average value of the oxygen composition ratio (atm%) O in the MoSiN film of Experimental Example 1 is in the range of 2 to 5. Furthermore, the average value of the oxygen composition ratio (atm%) O in the MoSiN film of Experimental Example 2 is in the range of 14 to 21.

[0320] from Figure 13 The results show that the average silicon composition ratio (atm%) Si in the MoSiN film of Experimental Example 1 is in the range of 45 to 50. Furthermore, the average silicon composition ratio (atm%) Si in the MoSiN film of Experimental Example 2 is in the range of 15 to 18.

[0321] from Figure 14 The results show that the average value of the molybdenum composition ratio (atm%) Mo in the MoSiN film of Experimental Example 1 is in the range of 16 to 19. Furthermore, the average value of the molybdenum composition ratio (atm%) Mo in the MoSiN film of Experimental Example 2 is in the range of 26 to 31.

[0322] from Figure 15 The results show that the average value of the ratio Si / Mo (the ratio of the silicon composition ratio (atm%) to the molybdenum composition ratio (atm%)) in the MoSiN film of Experimental Example 1 is in the range of 2.7 to 2.8. Furthermore, the average value of the ratio Si / Mo (the ratio of the silicon composition ratio (atm%) to the molybdenum composition ratio (atm%)) in the MoSiN film of Experimental Example 2 is in the range of 2.5 to 3.1.

[0323] from Figure 16 The results show that the average value of the ratio N / Si of the nitrogen composition ratio (atm%) to the silicon composition ratio (atm%) in the MoSiN film of Experimental Example 1 is in the range of 0.54 to 0.62. Furthermore, the average value of the ratio N / Si of the nitrogen composition ratio (atm%) to the silicon composition ratio (atm%) in the MoSiN film of Experimental Example 2 is in the range of 1.3 to 1.7.

[0324] from Figure 17 The results show that the average value of the ratio of the silicon composition ratio (atm%) to the sum of the molybdenum composition ratio (atm%) and the nitrogen composition ratio (atm%), Si / (Mo+N), in the MoSiN film of Experimental Example 1 is in the range of 1.00 to 1.13. Furthermore, the average value of the ratio of the silicon composition ratio (atm%) to the sum of the molybdenum composition ratio (atm%) and the nitrogen composition ratio (atm%), Si / (Mo+N), in the MoSiN film of Experimental Example 2 is in the range of 0.29 to 0.34.

[0325] from Figure 18 The results show that the average value of the ratio of the nitrogen composition ratio (atm%) to the sum of the molybdenum composition ratio (atm%) and the silicon composition ratio (atm%), N / (Mo+Si), in the MoSiN film of Experimental Example 1 is in the range of 0.40 to 0.44. Furthermore, the average value of the ratio of the nitrogen composition ratio (atm%) to the sum of the molybdenum composition ratio (atm%) and the silicon composition ratio (atm%), N / (Mo+Si), in the MoSiN film of Experimental Example 2 is in the range of 0.45 to 0.65.

[0326] from Figure 19 The results show that the average value of the ratio N / Mo of the nitrogen composition ratio (atm%) to the molybdenum composition ratio (atm%) in the MoSiN film of Experimental Example 1 is in the range of 1.4 to 1.75. Furthermore, the average value of the ratio N / Mo of the nitrogen composition ratio (atm%) to the molybdenum composition ratio (atm%) in the MoSiN film of Experimental Example 2 is in the range of 0.75 to 1.00.

[0327] from Figure 20 The results shown show that the average value of the ratio O / Si of the oxygen composition ratio (atm%) to the silicon composition ratio (atm%) detected by Auger electron spectroscopy in the MoSiN film of Experimental Example 1 is in the range of 0.01 to 0.15. Furthermore, the average value of the ratio O / Si of the oxygen composition ratio (atm%) to the silicon composition ratio (atm%) detected by Auger electron spectroscopy in the MoSiN film of Experimental Example 2 is in the range of 0.5 to 1.5.

[0328] from Figure 21 The results shown show that the average value of the ratio O / Mo of the oxygen composition ratio (atm%) to the molybdenum composition ratio (atm%) detected by Auger electron spectroscopy in the MoSiN film of Experimental Example 1 is in the range of 0.1 to 0.40. Furthermore, the average value of the ratio O / Mo of the oxygen composition ratio (atm%) to the molybdenum composition ratio (atm%) detected by Auger electron spectroscopy in the MoSiN film of Experimental Example 2 is in the range of 0.45 to 0.75.

[0329] from Figure 22 The results shown show that the average value of the ratio of the oxygen composition ratio (atm%) to the nitrogen composition ratio (atm%), O / N, detected by Auger electron spectroscopy in the MoSiN film of Experimental Example 1 is in the range of 0.07 to 0.26. Furthermore, the average value of the ratio of the oxygen composition ratio (atm%) to the nitrogen composition ratio (atm%), O / N, detected by Auger electron spectroscopy in the MoSiN film of Experimental Example 2 is in the range of 0.55 to 0.90.

[0330] from Figure 23 The results shown show that the average value of the ratio (O+N) / Si of the sum of the oxygen composition ratio (atm%) and the nitrogen composition ratio (atm%) to the silicon composition ratio (atm%) detected by Auger electron spectroscopy in the MoSiN film of Experimental Example 1 is in the range of 0.6 to 0.75. Furthermore, the average value of the ratio (O+N) / Si of the sum of the oxygen composition ratio (atm%) and the nitrogen composition ratio (atm%) to the silicon composition ratio (atm%) detected by Auger electron spectroscopy in the MoSiN film of Experimental Example 2 is in the range of 2.3 to 2.7.

[0331] from Figure 24 The results shown show that the average value of the sum of the molybdenum composition ratio (atm%), nitrogen composition ratio (atm%), and silicon composition ratio (atm%), Mo+N+Si, detected by Auger electron spectroscopy in the MoSiN film of Experimental Example 1, is in the range of 92 to 95. Furthermore, the average value of the sum of the molybdenum composition ratio (atm%), nitrogen composition ratio (atm%), and silicon composition ratio (atm%), Mo+N+Si, detected by Auger electron spectroscopy in the MoSiN film of Experimental Example 2, is in the range of 63 to 76.

[0332] It should be explained that Figure 25 Part of the numerical values ​​of the molybdenum composition ratio (atm%), nitrogen composition ratio (atm%), silicon composition ratio (atm%), oxygen composition ratio (atm%) and carbon composition ratio (atm%) detected by Auger electron spectroscopy are shown.

[0333] The composition ratio data above are average values. This "average value" does not represent the actual measured composition range, but rather represents the range after eliminating measurement variations using the following data processing method to eliminate the effects of surface contamination and Si and O at the point of contact between the film and the glass substrate surface. This "average value" corresponds to the flat portion of the graph. This method eliminates (removes) the maximum and minimum values ​​from the surface to the depth of contact with the glass substrate and then adds them together to calculate the average.

[0334] Furthermore, the molybdenum silicide compound films in Experimental Examples 1 and 2 were measured for etching time, over-etching state, chemical resistance, defect characteristics, and patterning shape accuracy.

[0335] The results are shown below.

[0336] The measurement of the etching time was performed as follows.

[0337] Using a MoSi etchant (product name: PEF006) manufactured by Kanto Chemical Co., Ltd., the time until the molybdenum silicide compound film disappears was measured while maintaining the liquid temperature at 20° C. The disappearance times of the molybdenum silicide compound films in Experimental Examples 1 and 2 are as follows:

[0338] Experimental Example 1: 15 minutes;

[0339] Experimental Example 2: 40 minutes.

[0340] The determination of chemical resistance was performed as follows.

[0341] While maintaining the liquid temperature of NH4OH+H2O2 at 23°C, the change in transmittance was measured every 10 minutes until 50 minutes had passed. The results are shown in Figure 26 In. Figure 26 In the figure, the vertical axis represents the change in transmittance, and the horizontal axis represents the time of contact with the chemical solution.

[0342] From this result, it can be seen that Example 1 has chemical resistance five times greater than that of Example 2.

[0343] The accuracy of the patterned shape was evaluated by cross-sectional SEM observation, and similarly good cross-sectional perpendicularity was observed in Experimental Examples 1 and 2.

[0344] It can be seen from the above results that the phase-shift layer of the present invention can simultaneously achieve shorter etching time, higher chemical resistance and patterning accuracy.

[0345] Description of Reference Numerals

[0346] 10 phase shift mask

[0347] 10B phase shift mask blank

[0348] 10L light-transmitting area

[0349] 10P phase shift area

[0350] 11Glass substrate (transparent substrate)

[0351] 12 phase shift layers

[0352] 12P1 phase shift pattern

[0353] 13 light-shielding layer

[0354] 13P shading pattern

[0355] 13P1, 13P2 shading pattern

[0356] 15 Photoresist layer

[0357] 15P1, 15P2 resist pattern

Claims

1. A phase-shift mask blank having a mask layer serving as a phase-shift mask, the phase-shift mask blank comprising: Transparent substrate; and a phase shift layer stacked on the transparent substrate and composed of metal silicide, The phase shift layer comprises nitrogen, molybdenum and silicon, The average value of the ratio Si / Mo of the composition ratio of silicon in atm % to the composition ratio of molybdenum in atm % is within a range of 2.2 to 3.

2.

2. The phase shift mask blank according to claim 1, wherein The phase shift mask blank includes a light shielding layer containing chromium and stacked on the phase shift layer.

3. The phase shift mask blank according to claim 1, wherein In the phase shift layer, an average value of a ratio N / Si of a composition ratio of nitrogen in atm % to a composition ratio of silicon in atm % is within a range of 0.50 to 0.

65. The phase shift mask blank according to claim 1 , wherein: In the phase shift layer, an average value of a ratio Si / (Mo+N) of a silicon composition ratio in atm % to a sum of a molybdenum composition ratio in atm % and a nitrogen composition ratio in atm % is within a range of 1.00 to 1.

13. The phase shift mask blank according to claim 1 , wherein: In the phase shift layer, an average value of a ratio N / (Mo+Si) of a composition ratio of nitrogen in atm % to a sum of a composition ratio of molybdenum in atm % and a composition ratio of silicon in atm % is within a range of 0.35 to 0.

50. The phase-shift mask blank according to claim 1 , wherein: In the phase shift layer, an average value of a ratio N / Mo of a composition ratio of nitrogen in atm % to a composition ratio of molybdenum in atm % is within a range of 1.4 to 1.

75.

7. The phase-shift mask blank according to claim 1, wherein In the phase shift layer, an average value of the sum of a composition ratio of molybdenum in atm%, a composition ratio of silicon in atm%, and a composition ratio of nitrogen in atm% is within a range greater than 90. The phase-shift mask blank according to claim 1 , wherein: In the phase shift layer, an average value of a ratio O / Si of a composition ratio of oxygen in atm % to a composition ratio of silicon in atm % detected by Auger electron spectroscopy is within a range of 0.01 to 0.

15.

9. A method for manufacturing a phase shift mask blank, wherein: The manufacturing method manufactures the phase shift mask blank according to any one of claims 1 to 8, When forming the phase shift layer, the following target material is used for sputtering: The target material has a composition in which a ratio of molybdenum to silicon is set to 7.0≤Si / Mo≤15.

0.

10. The method for manufacturing a phase shift mask blank according to claim 9, wherein: When forming the phase shift layer, sputtering is performed while supplying argon gas and nitrogen gas.

11. A method for manufacturing a phase-shift mask, A phase shift mask is manufactured by patterning the phase shift mask blank by wet etching using the phase shift mask blank manufactured by the method for manufacturing a phase shift mask blank according to claim 9 or 10. 12 . A phase-shift mask manufactured by the method for manufacturing a phase-shift mask according to claim 11 .

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