JP2007271696A - Gray tone mask blank and photomask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease the number of substrates which need to have translucent films peeled as a gray tone mask blank for FPD does not pass inspection when the gray tone mask blank is manufactured. <P>SOLUTION: A method of manufacturing the gray tone mask blank 10 for manufacturing an FPD device includes a preparation stage of preparing a light-transmissive substrate 12, a translucent film formation stage of forming a translucent film 14 of metal silicide on the substrate, a transmissivity adjustment stage of adjusting the transmissivity of the translucent film 14, and a light shield film formation stage of forming a light shield film 16 on the transmissivity-adjusted translucent film 14. In the transmissivity adjustment stage, the transmissivity of the translucent film 14 is measured, and then the transmissivity of the translucent film 14 is adjusted when the difference between the measured transmissivity and previously set transmissivity exceeds a range of variance allowed as a gray tone mask and the measured transmissivity is 75 to 125% of the set transmissivity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gray tone mask blank and a photomask.

  Currently, in a large mask blank such as a mask blank (FPD mask blank) for manufacturing an FPD (flat panel display) device, and a large photomask manufactured from this mask blank, Chromium (Cr) based materials are used. Further, as a large mask blank and a photomask, an underlay type (advanced type) gray tone mask blank and a photomask in which a semi-transparent film is formed (first) under a light shielding film have been proposed.

Conventionally, a method for manufacturing a halftone phase shift photomask blank for LSI is performed by a separate process separated from a film forming process for the purpose of manufacturing a halftone phase shift mask having various transmittances. A method of changing the transmittance of the halftone phase shift layer is known (see, for example, Patent Document 1). In this method, the transmittance is changed by performing a step of exposing a halftone phase shift layer mainly composed of a chromium compound to an atmosphere having a temperature of 150 ° C. or higher.
Japanese Patent No. 3339649

  When manufacturing the above-mentioned underlay type gray-tone mask blank, after the semi-transparent film is formed, an inspection of optical characteristics such as transmittance is performed. When the optical characteristics do not satisfy the desired specifications, for example, after the semi-transparent film is peeled off and the glass substrate is re-polished, the semi-transparent film is formed again.

  However, the polishing process is a process that is likely to cause scratches and chips on the substrate. In addition, the polishing apparatus is often installed in a separate room or the like away from the film forming apparatus and the inspection apparatus because of the difference in cleanliness required for the atmosphere. Therefore, when re-polishing, the transport distance of the substrate becomes long. Therefore, when the semi-transparent film is peeled off and the glass substrate is repolished, there is a high possibility that a large scratch or chip is generated in the substrate during these processes or during conveyance between the processes. When large scratches or chips occur, the substrate must be discarded, which wastes resources. Further, a very expensive substrate such as a large synthetic quartz glass substrate is used as a substrate such as a gray-tone mask blank for FPD. Therefore, if it is discarded due to a large scratch or chip, it is not preferable because it leads to high costs.

  In the case of an LSI mask blank having a small substrate size, the cost of the substrate is lower than that for an FPD, and therefore the cost is small even if the substrate is discarded. However, in the case of a gray-tone mask blank for FPD that uses a very expensive substrate, reducing the opportunity to perform the process of peeling off the semi-transparent film or re-polishing the glass substrate, which may lead to disposal of the substrate, is minimized. It is strongly desired.

  Accordingly, an object of the present invention is to provide a gray-tone mask blank and a photomask that can solve the above-described problems.

  In recent years, it has been proposed to use a metal silicide-based material containing, for example, a metal and silicon as a semi-transparent film in an underlay type gray-tone mask blank and a photomask for FPD. The inventor of the present application studied a method of adjusting the transmittance of such a semi-transparent film without peeling off the semi-transparent film when the optical characteristics do not satisfy a desired specification.

  However, the optical characteristics such as the transmissivity of the semi-transparent film used for the gray-tone mask blank for FPD are greatly different from the optical characteristics of the half-tone phase shift layer for LSI disclosed in Patent Document 1, for example. For example, the transmittance of the halftone phase shift layer is about 3 to 20%, whereas the transmittance of the semi-transparent film of the gray tone mask blank is about 15 to 60%, for example. Further, in the halftone phase shift layer for LSI, only the transmittance for the exposure light having a single wavelength needs to be considered, whereas in the semitransparent film for FPD, for example, a wavelength band extending from i-line to g-line. Therefore, it is necessary to consider the transmittance with respect to the exposure light of the multicolor wave exposure using the above-mentioned light.

  Therefore, the film material suitable for the semi-transparent film for FPD is greatly different from the film material of the halftone phase shift layer for LSI. Therefore, even if the transmissivity of the halftone phase shift layer can be changed by a process of exposing in a high temperature atmosphere, the transmissivity of the FPD semi-transparent film cannot be adjusted in the same manner.

For example, when a metal silicide-based material containing metal and silicon, for example, a MoSi-based material (MoSi, MoSi ₂ , MoSi ₄ , MoSiO, MoSiN, MoSiON, etc.) is used as a semi-transparent film for FPD, The inventor has found that when the transmittance is adjusted by heat treatment or the like, the variation in the transmittance within the substrate surface and between the substrates may increase. Particularly, in the case of a gray-tone mask blank for FPD, since the substrate is large, variation in transmittance within the substrate surface becomes a problem. Further, among metal silicide-based materials, the method of changing the transmittance with respect to heat treatment or the like is greatly different, for example, there is a material in which the transmittance hardly changes or a material in which the transmittance change is too steep and difficult to control. I found out.

  Accordingly, the inventors of the present application have further conducted intensive research, found out a method for adjusting the transmittance applicable to the case of a semi-transparent film for FPD, and have reached the present invention. The present invention has the following configuration.

  (Configuration 1) A gray-tone mask blank manufacturing method for manufacturing an FPD device, which includes a preparation step of preparing a translucent substrate, and a semi-translucent film in which a semi-transparent film of metal silicide is formed on the substrate A transmittance adjusting step, comprising: a film forming step; a transmittance adjusting step for adjusting the transmittance of the semi-transparent film; and a light shielding film forming step for forming a light shielding film on the semi-transparent film having the adjusted transmittance. Measures the transmissivity of the translucent film, the difference between the measured transmissivity measured and the preset set transmissivity is larger than the range of variation allowed as a gray-tone mask, and the measured transmissivity Is 75% or more and 125% or less of the set transmittance, the transmittance is adjusted for the semi-transparent film.

  Metal silicide has preferable characteristics as a material for a semi-transparent film of a gray-tone mask blank for FPD. The inventors of the present application have also found that a semi-transparent film of metal silicide is preferable for controlling the transmittance.

  Furthermore, it has been found that if the transmittance to be changed is within ± 25% of the set transmittance, the amount of variation in the transmittance caused by adjusting the transmittance does not become a problem. In many cases, the transmittance of the semi-transparent film formed in the semi-transparent film forming step can be within a range of ± 25% of the set transmissivity. Therefore, if the transmittance is adjusted only when the transmittance is within this range, the transmittance of the semi-transparent film is often low even when the transmittance immediately after the film formation is low or high. Can be adjusted. Therefore, with the configuration 1, when manufacturing a gray-tone mask blank for FPD, it is possible to greatly reduce the number of substrates that require peeling of the semi-transparent film. Thereby, the manufacturing yield of the gray-tone mask blank can be improved.

  When the measured transmittance is lower than the set transmittance and the measured transmittance is less than 75% of the set transmittance, or when the measured transmittance is higher than the set transmittance and the measured transmittance exceeds 125% of the set transmittance. In this case, it is preferable to re-form the semi-transparent film after peeling off the semi-translucent film and re-polishing the substrate. In this way, the substrate can be used without waste. Further, when the variation in transmittance is controlled more strictly, the standard for determining whether or not to adjust the transmittance is more preferably 80% or more and 120% or less, more preferably 85%, of the measured transmittance. It is 115% or less.

  The transmissivity of the semi-transparent film may be a relative transmissivity when the transmissivity of the substrate is 100%, for example. The metal silicide semi-transparent film is made of, for example, molybdenum silicide (MoSi), tantalum silicide (TaSi), titanium silicide (TiSi), or tungsten silicide (WSi). In addition, the semi-transparent film may contain oxygen, nitrogen, carbon, or the like.

  (Configuration 2) When the measured transmittance is lower than the set transmittance, the transmittance adjustment step is an oxidation treatment, a nitridation treatment, or an oxynitridation treatment for the semi-transparent film formed in the semi-transparent film formation step. By performing any one of the processes, the transmittance of the semi-transparent film is increased so that the set transmittance is obtained. In this way, the transmittance of the semi-transparent film can be adjusted with high accuracy. In order to achieve the set transmittance, for example, the difference from the set transmittance is set within a range of variation allowed for the gray tone mask.

  (Configuration 3) In the semi-transparent film forming step, a molybdenum silicide film is formed as the semi-transparent film, and in the transmittance adjusting step, the semi-transparent film is 150 to 500 in an atmosphere containing oxygen and / or nitrogen. By heating to 0 ° C., the translucent film is oxidized, nitrided, or oxynitrided to increase the transmissivity of the translucent film so that the set transmissivity is obtained.

  The molybdenum silicide film has particularly preferable characteristics as a material for the semi-transparent film of the gray-tone mask blank for FPD. Further, the change in transmittance when the heat treatment is performed is also stable, which is suitable for controlling the transmittance by the heat treatment. Therefore, in this way, the transmittance of the semi-transparent film can be adjusted more appropriately.

  (Configuration 4) When the measured transmittance is higher than the set transmittance, the transmittance adjusting step further forms a new semi-transmissive film on the semi-transmissive film formed in the semi-transmissive film forming step, The transmissivity of the semi-transparent film formed by superimposing the semi-transparent film formed in the semi-transparent film forming step and the new semi-transparent film is set to the set transmissivity. In this way, even when the measured transmittance is higher than the set transmittance, the transmittance of the semi-transparent film can be adjusted appropriately.

The additional semi-transparent film is formed of the same material as the semi-transparent film formed in the semi-transparent film forming process, for example. In this way, it is not necessary to replace the target for supplying the film material in the sputtering process. It is also conceivable that the additional semi-transparent film is formed of a material different from that of the semi-transparent film formed in the semi-transparent film forming step. For example, the first semi-transparent film is MoSi ₂ (Mo: 33 atomic%, Si: 67 atomic%), and the additional semi-transparent film is MoSi ₄ (Mo: 20 atomic%, Si: 80 atomic%). The first semi-transparent film is a MoSi ₂ (Mo: 33 atomic% · Si: 67 atomic%) film, and the additional semi-transparent film is any of an oxide film, nitride film, or oxynitride film of MoSi ₂ It can be considered. The additional semi-transparent film material is preferable because an additional film forming process can be performed with a stable film thickness, so that in-plane variation in transmittance can be reduced.

  Here, the semi-transparent film of the metal silicide has a slower reaction speed in which the surface oxidation proceeds than, for example, a chromium-based thin film. Therefore, even if such additional film formation is performed, it is difficult to be affected by the surface state of the first semi-transparent film. From this point of view, it can be said that the semi-transparent film of metal silicide is suitable for controlling the transmittance. In particular, the semi-transparent film of metal silicide is preferably subjected to heat treatment. By doing in this way, the reaction rate which the surface oxidation advances can be made slow.

  In addition, after forming the semi-transparent film in the semi-transparent film forming step, for example, a defect inspection may be performed. In this case, the timing for defect correction may be determined according to the content of the defect. For example, when the defect is small and the defect may disappear if an additional semi-transparent film is formed, it is conceivable to perform additional film formation without performing partial correction of the defect. When the defect is large, it is conceivable to partially correct the defect before forming the additional semi-transparent film. Further, whether or not to perform additional film formation and the film thickness of the semi-transparent film to be additionally formed may be further set based on the result of the defect inspection. The above-mentioned defects are defects that affect pattern transfer such as black defects and white defects. Before the defect inspection, it is preferable to clean the semi-transparent film.

  (Configuration 5) A photomask for manufacturing an FPD device manufactured using the gray-tone mask blank according to any one of Configurations 1 to 4. If comprised in this way, the effect similar to the structures 1-4 can be acquired. This photomask is manufactured by, for example, patterning a light shielding film and a semi-transparent film formed on a gray tone mask blank by wet etching to form a mask pattern.

  In each of the above-described configurations, the gray tone mask blank and photomask for FPD are gray tone mask blanks for manufacturing FPD devices such as LCD (liquid crystal display), plasma display, and organic EL (electroluminescence) display. And a photomask.

  Photomasks for LCD include all photomasks necessary for LCD production, such as TFT (Thin Film Transistor), especially TFT channel and contact hole, low-temperature polysilicon TFT, color filter, reflector (black) A photomask for forming a matrix or the like is included. Other photomasks for manufacturing display devices include all photomasks necessary for manufacturing organic EL (electroluminescence) displays, plasma displays, and the like.

  ADVANTAGE OF THE INVENTION According to this invention, when manufacturing the gray tone mask blank for FPD, the number of the board | substrates which fail the test | inspection and require peeling of a semi-transparent film can be reduced significantly.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
FIG. 1 shows an example of the configuration of a mask blank 10 according to an embodiment of the present invention. The mask blank 10 is an underlay type gray tone mask blank for manufacturing an FPD device. The mask blank 10 is a large mask blank having a side of 330 mm or more (for example, 330 mm × 450 mm to 1220 mm × 1400 mm), for example. The FPD photomask manufactured from the mask blank 10 is used by being mounted on, for example, a mirror projection (scanning exposure method, equal magnification projection exposure) method or a lens projection method exposure apparatus using a lens. This photomask is, for example, a photomask for multicolor wave exposure using light in a wavelength band extending from i-line to g-line.

  FIG. 1A shows an example of the configuration of the mask blank 10 when a semi-transparent film is formed in a single film formation step. In this case, the mask blank 10 includes a substrate 12, a semi-transmissive film 14, a light shielding film 16, and a resist film 18. The mask blank 10 may further include another layer such as a base film. The substrate 12 is a translucent substrate. As the substrate 12, for example, a substrate made of synthetic quartz, soda lime glass, alkali-free glass or the like can be used.

The semi-transparent film 14 is made of a metal silicide containing metal and silicon. For example, molybdenum silicide (MoSi), tantalum silicide (TaSi), titanium silicide (TiSi), tungsten silicide (WSi), and the like. A film of oxide, nitride, oxynitride, or the like. In this example, the semi-transparent film 14 is a molybdenum silicide film formed on the substrate 12 and has a transmittance of 15 to 60%, for example. The translucent film 14 is preferably, for example, a MoSi film, a MoSi ₂ film, or a MoSi ₄ film. The translucent film 14 may be a MoSiO film, a MoSiN film, a MoSiON film, or the like. The light shielding film 16 is formed on the semi-transmissive film 14 by using, for example, a chromium (Cr) -based material having etching selectivity with respect to metal silicide. The light shielding film 16 is, for example, a CrN film, a CrC film, a CrCO film, a CrO film, a CrON film, or a laminated film thereof. The resist film 18 is a resist film that serves as an etching mask for patterning the light shielding film 16 and the like, and is formed on the light shielding film 16. Moreover, a gray-tone mask is manufactured by performing a known photomask manufacturing process using this mask blank 10.

  Here, the gray tone mask is a photomask including a light shielding portion, a gray tone portion, and a light transmitting portion on a light transmitting substrate 12. The light shielding part is an area where the light shielding film 16 remains. The gray tone portion is an area where only the light shielding film 16 is removed and the semi-transparent film 14 remains. The translucent part is an area where both the semi-translucent film 14 and the light shielding film 16 are removed.

  When exposure is performed using a gray-tone mask on a positive photoresist formed on a substrate to be processed such as an FPD, the area corresponding to the gray-tone portion is smaller than the area corresponding to the light-transmitting portion. Exposure light will be received. Therefore, a difference in solubility in the developer occurs in both areas. In the resist shape after development, the resist film disappears in the region corresponding to the translucent portion, and the resist film is reduced and thinned in the region corresponding to the gray tone portion. In this case, if the thin partial resist corresponding to the gray tone portion is removed by ashing or the like after performing the first etching of the substrate to be processed using the portion where the resist corresponding to the light transmitting portion disappears, this portion is removed. The second etching can be performed using this. Therefore, if a gray-tone mask is used, the process for two conventional masks can be performed with one mask, and the number of masks can be reduced.

  In this example, the mask blank 10 is for forming a pattern having a line width of about 2 to 5 μm by the second etching. For this reason, for example, the amount of variation in the transmissivity of the translucent film 14 within the substrate surface and between the substrates needs to be suppressed within a range necessary to satisfy this accuracy.

  FIG. 1B shows an example of the configuration of the mask blank 10 when a semi-transparent film is formed by two film forming steps. In this case, the mask blank 10 further includes another semi-transmissive film 20 on the semi-transmissive film 14. The semi-transmissive film 20 may be formed of the same material as the semi-transmissive film 14 or may be formed of a different material. The transmittance of the semi-transparent film including the semi-transparent film 14 and the semi-transparent film 20 is, for example, 15 to 60%. Further, the light shielding film 16 is formed on the semi-transparent film 20. Except for the above, the mask blank 10 shown in FIG. 1B is the same as the mask blank 10 shown in FIG.

  FIG. 2 is a flowchart showing an example of a method for manufacturing the mask blank 10. In this example, first, a translucent substrate 12 is prepared (S102). The substrate 12 is a substrate after performing a predetermined polishing process and a cleaning process. Next, the semi-transparent film 14 is formed by, eg, sputtering (S104), and the optical characteristics of the semi-transparent film 14 are inspected (S106). In this example, in this inspection, the transmittance of the semi-transparent film 14 is measured. Further, the defect inspection of the semi-transparent film 14 may be further performed. If the inspection result is acceptable (S106: Pass), the process proceeds to formation of the light shielding film 16 (S108) and formation of the resist film 18 (S110), and the manufacturing process of the mask blank 10 is completed.

  On the other hand, if the inspection result is unacceptable (S106: Fail), the process proceeds to a transmittance adjustment step (S112 to S118) for adjusting the transmittance of the semi-transparent film 14. In the transmittance adjustment step, first, it is determined whether or not the transmittance can be adjusted (S112). Here, for example, whether or not adjustment is possible is determined by comparing the measured transmittance measured in the inspection with a preset set transmittance. More specifically, for example, when the measured transmittance is lower than the set transmittance and the measured transmittance is less than 75% of the set transmittance, it is determined that adjustment is impossible. Further, when the defect inspection is performed in S106, whether or not the adjustment is possible may be determined based on the result of the defect inspection.

  Note that the measured transmittance is lower (or higher) than the set transmittance means, for example, that the measured transmittance is lower (or higher) than the set transmittance beyond the range of variation allowed as a gray-tone mask. The set transmittance may be set with a width in consideration of variation in transmittance within a certain range within the substrate surface and between the substrates. In this case, this width is, for example, ± 3% or less. For example, when the center of the set transmittance is 15%, the set transmittance can be set to 15% ± 3%. When the center of the set transmittance is 60%, the set transmittance can be 60% ± 3%. In this case, the measured transmittance being lower than the set transmittance means that the measured transmittance is lower than the lower limit of the set transmittance. The measured transmittance being higher than the set transmittance means that the measured transmittance is higher than the upper limit of the set transmittance.

  Here, when it is determined that the transmittance of the semi-translucent film 14 cannot be adjusted (S112: No), after the semi-transparent film 14 is peeled off and necessary re-polishing (S120) is performed. Returning to S104, the subsequent steps are repeated. In this way, the substrate 12 can be used effectively.

  On the other hand, when it is determined that the transmittance of the semi-transmissive film 14 can be adjusted (S112: Yes), if the measured transmittance is higher than the set transmittance (S114: Yes), a new one is formed on the semi-transmissive film 14. A semi-translucent film 20 is further formed. Thereby, the transmittance | permeability of the semi-transparent film | membrane which put together the semi-transparent film | membrane 14 and the semi-transparent film | membrane 20 can be lowered | hung.

  The film thickness of the semi-transparent film 20 that is additionally formed is set according to the measured transmittance, for example. The relationship between the film thickness of the semi-translucent film 20 and the transmittance is preferably grasped beforehand by, for example, experiments. In this way, the transmittance of the semi-transparent film can be appropriately controlled. After adjusting the transmittance by forming the semi-transparent film 20, the process proceeds to formation of the light shielding film 16 (S108).

  Further, when it is determined that the transmittance of the semi-transparent film 14 can be adjusted (S112: Yes) and the measured transmittance is lower than the set transmittance (S114: No), oxidation for increasing the transmittance is performed. Then, nitriding or oxynitriding treatment (hereinafter referred to as transmittance improvement treatment) is performed (S118). This treatment may be performed while heating. The heat treatment is performed using, for example, an oven or a hot plate. The transmittance adjustment may be performed while measuring the transmittance of the semi-transparent film 14. In this way, the transmittance can be adjusted with high accuracy. Further, this process may be performed in the inspection apparatus used in the inspection of S104, for example.

  Here, when performing heat processing, this heat processing is performed in air | atmosphere, oxygen, and / or nitrogen gas atmosphere, for example. The temperature of heat processing is performed in the range of 150-500 degreeC, for example. For example, it is preferably 150 to 300 ° C. when carried out in the air or an oxygen gas atmosphere, and 150 to 500 ° C. when carried out in a nitrogen gas atmosphere. In this way, the transmittance can be increased by oxidizing, nitriding, or oxynitriding the surface of the semi-transparent film 14. When the heating temperature is 100 ° C. or less, the change in transmittance is too small to be sufficiently controlled.

  In addition, it is preferable to grasp | ascertain beforehand the relationship between the said transmittance | permeability improvement process and transmittance | permeability, for example by experiment. Thereby, the conditions for the transmittance improvement processing can be set appropriately. The time for the transmittance improving process is set according to the measured transmittance, for example. When the transmittance is changed more greatly, the time required for controlling the transmittance can be shortened by performing the heat treatment together. The temperature of the heat treatment may be constant regardless of the measured transmittance. In this case, the transmittance can be easily controlled. Moreover, the temperature of heat processing may be set according to the measured transmittance, for example. In S106, for example, when optical characteristics other than transmittance, such as reflectance, are also measured, conditions for the transmittance improvement processing may be further set based on the optical characteristics.

  After adjusting the transmittance by the transmittance improving process, the process proceeds to the formation of the light shielding film 16 (S108). As described above, the transmittance of the translucent film 14 can be adjusted appropriately. In addition, this makes it possible to greatly reduce the number of substrates 12 that require the semi-transparent film 14 to be peeled even when the inspection result is unacceptable.

  In addition, you may perform a washing | cleaning process etc. suitably between each said process. In addition, after adjusting the transmittance of the semi-transmissive film 14, it is preferable to inspect the optical characteristics and defects before proceeding to, for example, S108. Further, it is preferable to inspect the light shielding film 16 and the resist film 18 after S108 and after S110, respectively.

  In the transmittance adjustment step, for example, it may be possible to perform only one of the formation of the additional semi-transmissive film 20 (S116) and the transmittance improvement process (S118). For example, it is conceivable that the transmittance improving process (S118) is performed only when the transmittance of the semi-transparent film 14 is low, and when the transmittance is high, the process proceeds to the film peeling and re-polishing step (S120). Also in this case, the number of substrates 12 that require the semi-transparent film 14 to be peeled can be sufficiently reduced. Further, on the premise that an additional semi-transparent film 20 is formed from the beginning, it is also conceivable to form the semi-transparent film 14 so that the transmittance is higher than the set transmittance.

Hereinafter, the present invention will be described in more detail based on examples.
Example 1
A large in-line sputtering apparatus was used on a large glass substrate (synthetic quartz (QZ) 10 mm thick, size 850 mm × 1200 mm) to form a thin film corresponding to a semi-transparent film. Film formation corresponds to a semi-transparent film by placing a MoSi ₂ target (Mo: 33 mol%, Si: 67 mol%) in a space (sputtering chamber) in a large in-line sputtering apparatus and using Ar gas as a sputtering gas. A MoSi ₂ film (Mo: 33 atomic%, Si: 67 atomic%) was formed to a thickness of 45 Å.

  The same film was formed on 50 substrates, and the transmittance (measured transmittance) was inspected. The set transmittance was 40% ± 2%. As a result of the inspection, two sheets were lower than the set transmittance and had a measured transmittance of 28.5% or more and less than 38%, and one sheet had a measured transmittance higher than the set transmittance. The transmissivity of the semi-transparent film of the other substrate was within the set transmissivity range (40% ± 2%). In addition, there was no substrate that required film peeling. Note that the measured transmittance of the sample whose measured transmittance was higher than the set transmittance was more than 42% and not more than 52.5%.

Two sheets having a low measured transmittance were subjected to heat treatment at 250 ° C. in the air. The heating time was 60 minutes. In addition, a MoSi ₂ —N film was additionally formed to 15 Å on one sheet having a high transmittance. After adjusting the transmittance, the transmittance of the semi-transparent film of each substrate was measured, and all were within the range of the set transmittance. Moreover, the dispersion | variation in the transmittance | permeability in the board | substrate surface after a heat processing and between board | substrates was also a range which is satisfactory. Thereby, it has confirmed that the transmittance | permeability of a translucent film | membrane could be adjusted appropriately.

  Further, a light-shielding film and a resist film were further formed on these semi-transparent films, and a gray-tone mask blank according to Example 1 was produced. Moreover, a gray tone mask was manufactured from these gray tone mask blanks. These gray tone mask blanks and gray tone masks satisfy the necessary qualities such as optical characteristics.

(Reference Example 1)
MoSi MoSi ₂ -N film instead of ₂ film (Mo: 13 atomic%, Si: 27 atomic%, N: 60 atomic%) except for using in the same manner as in Example 1, corresponding to HanToruHikarimaku A thin film was formed. When a semi-transparent film having a measured transmittance of 28.5% or more and less than 38% is selected and heat treatment is performed in the same manner as in Example 1, the transmittance is increased and the transmittance is increased. It was confirmed that it was possible to adjust. However, the change in transmittance was steep compared to Example 1, and control was difficult to perform compared to Example 1. When heat treatment was performed in a nitrogen atmosphere, the change in transmittance was small, and it took 1.5 times longer to adjust the transmittance.

(Reference Example 2)
MoSi MoSi ₂ O film instead of ₂ film (Mo: 13 atomic%, Si: 27 atomic%, O: 60 atomic%) except for using in the same manner as in Example 1, a thin film corresponding to HanToruHikarimaku Formed. A semi-transparent film having a transmittance lower than the set transmittance and a measured transmittance of 28.5% or more and less than 38% was selected, and heat treatment was performed in the same manner as in Example 1. It took 1.5 times longer to adjust the rate.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The present invention can be suitably applied to, for example, a gray tone mask blank and a mask for manufacturing an FPD device.

It is a figure showing an example of composition of mask blank 10 concerning one embodiment of the present invention. FIG. 1A shows an example of the configuration of the mask blank 10 when a semi-transparent film is formed in a single film formation step. FIG. 1B shows an example of the configuration of the mask blank 10 when a semi-transparent film is formed by two film forming steps. 4 is a flowchart showing an example of a method for manufacturing the mask blank 10.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mask blank, 12 ... Substrate, 14 ... Semi-transparent film, 16 ... Light-shielding film, 18 ... Resist film, 20 ... Semi-translucent film

Claims (5)

A method of manufacturing a gray-tone mask blank for manufacturing an FPD device,
A preparation step of preparing a translucent substrate;
Forming a semi-transparent film of metal silicide on the substrate;
A transmittance adjusting step for adjusting the transmittance of the semi-transparent film;
A light shielding film forming step of forming a light shielding film on the semi-transparent film whose transmittance is adjusted,
The transmittance adjustment step
Measure the transmittance of the semi-translucent film,
The difference between the measured measured transmittance and the preset set transmittance is larger than the range of variation allowed as a gray tone mask, and the measured transmittance is not less than 75% and not more than 125% of the set transmittance. In this case, the gray-tone mask blank manufacturing method is characterized in that transmittance adjustment is performed on the semi-transparent film.   When the measured transmittance is lower than the set transmittance, the transmittance adjusting step includes oxidizing, nitriding, or oxynitriding the semi-transparent film formed in the semi-transparent film forming step. 2. The method of manufacturing a gray-tone mask blank according to claim 1, wherein by performing any one of the processes, the transmittance of the semi-translucent film is increased to be the set transmittance. In the semitranslucent film forming step, a molybdenum silicide film is formed as the semitranslucent film,
The transmittance adjusting step includes oxidizing, nitriding, or oxynitriding the semi-transparent film by heating the semi-transparent film to 150 to 500 ° C. in an atmosphere containing oxygen and / or nitrogen, 3. The method of manufacturing a gray-tone mask blank according to claim 2, wherein the transmissivity of the semi-translucent film is increased so as to be the set transmissivity.   When the measured transmittance is higher than the set transmittance, the transmittance adjusting step further includes forming a new semi-transmissive film on the semi-transmissive film formed in the semi-transmissive film forming step. The transmissivity of the semi-transparent film formed by superimposing the semi-transparent film formed in the semi-transparent film forming step and the new semi-transparent film becomes the set transmissivity. The method for producing a gray-tone mask blank according to claim 1.   A gray-tone mask for manufacturing an FPD device manufactured using the gray-tone mask blank according to claim 1.

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