Photomask blank, photomask, method for manufacturing photomask blank, method for manufacturing photomask, and method for manufacturing device

Abstract

A photomask blank in which a first layer and a second layer are provided on a substrate, wherein the first layer is provided on the substrate, the second layer is provided on the first layer, and the first layer contains zirconium at an atomic composition percentage (at%) of 60% to 99.5% inclusive.

Description

Photomask blanks, photomask, photomask blank manufacturing method, photomask manufacturing method, and device manufacturing method

[0001] The present invention relates to a photomask blank, a photomask, a method for manufacturing a photomask blank, a method for manufacturing a photomask, and a method for manufacturing a device. The present invention claims priority to Japanese Patent Application No. 2023-040414 filed on March 15, 2023, and the contents of that application are incorporated by reference into this application in designated states where incorporation by reference of documents is permitted.

[0002] Half-tone mask blanks are known in which the material of the half-tone layer is the same as the material of the binary layer, and in such half-tone mask blanks, it is necessary to provide a stopper layer (etching stopper) between the half-tone layer and the binary layer.

[0003] Japanese Patent Application Laid-Open No. 2002-189281

[0004] One aspect of the present invention is a photomask blank having a first layer and a second layer on a substrate, the first layer being on the substrate and the second layer being on the first layer, the first layer containing zirconium in an atomic composition percentage (atomic %) of 60% to 99.5%. Also, the present invention is a photomask blank having a first layer and a second layer on a substrate, the first layer being on the substrate and the second layer being on the first layer, the first layer being a half-tone layer containing a metal other than chromium, the difference between the transmittance of light having a wavelength of 365 nm transmitted through the first layer and the transmittance of light having a wavelength of 436 nm transmitted through the first layer being 1.5% or less, and the second layer being a binary layer containing chromium.

[0005] Another aspect of the present invention is a photomask in which a pattern is formed on the above-mentioned photomask blank.

[0006] Another aspect of the present invention is a method for manufacturing a photomask, including: a first step of etching the second layer of the above-mentioned photomask blank to form a second layer pattern in the second layer; and a second step of etching the first layer to form a first layer pattern in the first layer that is different from the second layer pattern.

[0007] Another aspect of the present invention is a method for manufacturing photomask blanks, which involves forming a first layer and a second layer on a substrate, the method including: a first layer forming step of forming the first layer on the substrate while introducing a gas; and a second layer forming step of forming the second layer on the first layer, wherein a proportion of nitrogen in the gas is equal to or greater than 0% and equal to or less than 3% in terms of flow rate percentage (flow rate %).

[0008] Another aspect of the present invention is a method for manufacturing a photomask using a photomask blank manufactured by the above-described method for manufacturing a photomask blank.

[0009] Another aspect of the present invention is a method for manufacturing a device, including an exposure step of exposing a pattern onto an object to be processed using a photomask manufactured by the above-described method for manufacturing a photomask.

[0010] FIG. 1 is a schematic cross-sectional view showing an example of a photomask blank according to the present embodiment; FIG. 2 is a schematic cross-sectional view of a photomask according to the present embodiment; FIG. 3 is a diagram illustrating a method for manufacturing a photomask according to the present embodiment, with steps A to E illustrating the method for manufacturing a photomask according to the present embodiment; FIG. 4 is a schematic view of an exposure apparatus used in the exposure method according to the present embodiment; and FIG. 5 is a schematic view showing an example of an apparatus for manufacturing a photomask blank according to the present embodiment. ２ 1 is a graph showing the transmittance at wavelengths of 300 to 800 nm of Zr-based halftone layers with different film thicknesses manufactured with a gas ratio (flow %) of 2%. 2 is a graph showing the transmittance at wavelengths of 300 to 800 nm of Zr-based halftone layers with N contents (atomic %) of 0 to 41.8%. ２1 is a graph showing the transmittance of MoSi-based half-tone layers manufactured with gas ratios (flow rates) of 0 to 50% at wavelengths of 300 to 800 nm. 2 is a graph showing the transmittance flatness of Zr-based half-tone layers with N contents (atomic %) of 0 to 41.8%.

[0011] An embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described below. The present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be practiced with appropriate modifications within the scope of its gist.

[0012] As shown in FIG. 1 , a photomask blank 100 according to this embodiment includes a substrate 10, a half-tone layer 20 (semi-transparent film) containing a zirconium compound formed on the surface of the substrate 10, and a binary layer 30 (light-shielding film) containing a chromium compound formed on the half-tone layer 20.

[0013] 2 , the photomask 200 according to this embodiment is obtained by etching the binary layer 30 of the photomask blank 100 to form a binary layer pattern 50 (first step), and then etching the halftone layer 20 to form a halftone layer pattern 51. The photomask 200 is used when manufacturing display devices such as FPDs (Flat Panel Displays) and semiconductor devices such as LSIs (Large Scale Integration).

[0014] [Structure of Photomask Blank 100 and Photomask 200] The material of the substrate 10 is, for example, synthetic quartz glass, and may be any material that sufficiently transmits the exposure light of the exposure device in which the photomask 200 is used.

[0015] The halftone layer 20 is a semi-transparent light-shielding film and preferably contains a metal, particularly zirconium (Zr). When zirconium is contained, the content is 60% or more and 99.5% or less in atomic composition percentage (atomic %). The lower limit of the content is preferably 65%, more preferably 70%, and even more preferably 75%. The upper limit of the content is preferably 97%, more preferably 94%, and even more preferably 91%.

[0016] The halftone layer 20 preferably contains nitrogen (N). When nitrogen is contained, the content is 0% or more and 30% or less in atomic composition percentage (atomic %). The lower limit of the nitrogen content is preferably 5%, more preferably 10%, and even more preferably 15%. The upper limit of the nitrogen content is preferably 27%, more preferably 24%, and even more preferably 21%.

[0017] In addition to the zirconium and nitrogen mentioned above, the half-tone layer 20 may contain other metals, silicon, or small amounts of impurities that do not affect the effect. However, it is preferable that the half-tone layer 20 does not contain metal atoms contained in the binary layer 30.

[0018] The transmittance of light having an emission wavelength of 365 nm to 436 nm that passes through halftone layer 20 is not particularly limited and may be set appropriately, for example, to 5% or more and 50% or less.

[0019] Halftone layer 20 has transmittance flatness for light with emission line wavelengths in the range of 365 to 436 nm. In this specification, transmittance flatness refers to the property of transmittance being less likely to change even when the wavelength of light is changed, and the difference between the transmittance of light with a wavelength of 365 nm and the transmittance of light with a wavelength of 436 nm that passes through halftone layer 20 is 1.5% or less. The upper limit of this transmittance difference is preferably 1.0%, more preferably 0.5%, and even more preferably 0%. By having halftone layer 20 have such transmittance flatness, it becomes possible to perform exposure with reduced changes in transmittance even when the wavelength of exposure light is different.

[0020] Furthermore, the difference between the maximum and minimum transmittances of light having wavelengths of 365 nm, 405 nm, and 436 nm that pass through halftone layer 20 may be 1.5% or less. The upper limit of this transmittance difference is preferably 1.0%, more preferably 0.5%, and even more preferably 0%.

[0021] Furthermore, the difference between the maximum and minimum transmittance values ​​for light in the wavelength range of 365 nm to 436 nm that is transmitted through halftone layer 20 can be set to 1.5% or less. The upper limit of this transmittance difference is preferably 1.0%, more preferably 0.5%, and even more preferably 0%.

[0022] From the viewpoint of improving the transmittance flatness, the thickness of half-tone layer 20 is 5 nm or more and 45 nm or less. The lower limit of the thickness is preferably 8 nm, and more preferably 11 nm.

[0023] The binary layer 30 is a layer located above the halftone layer 20 and functions as a light-shielding film.

[0024] The binary layer 30 preferably contains metal atoms, particularly chromium (Cr). When the binary layer 30 contains chromium, the content is not particularly limited and may be set as appropriate. The chromium is preferably contained in the form of, for example, chromium nitride or chromium oxide. The binary layer 30 may contain metals other than chromium or small amounts of impurities that do not affect the effect. However, it is preferable that the binary layer 30 does not contain the metal atoms contained in the halftone layer 20.

[0025] In manufacturing the photomask 200, the photoresist layers 40 and 41 are exposed to light with an emission wavelength of 365 nm to 436 nm. Therefore, the binary layer 30 provided below the photoresist layers 40 and 41 preferably has low reflectance for light with an emission wavelength of 365 nm to 436 nm. By suppressing the reflection of the exposure light, multiple reflections of the exposure light within the photoresist layers 40 and 41 are suppressed, improving the pattern accuracy of the photomask 200. For example, the reflectance of the binary layer 30 for light with a wavelength of 413 nm is preferably 15% or less. The binary layer 30 may be a single layer or may be formed from multiple layers. When the binary layer 30 is formed from multiple layers, it is preferable that the layer directly below the photoresist layers 40 and 41 have low reflectance for the exposure light. For example, the binary layer 30 may be formed from a chromium nitride layer formed on the halftone layer 20 and a chromium oxide layer further formed on the chromium nitride layer. The chromium oxide layer can suppress the reflectance of light with a wavelength of 413 nm to about 11%, for example.

[0026] The thickness of the binary layer 30 is not particularly limited and can be adjusted appropriately, and may be, for example, 10 nm or more and 120 nm or less.

[0027] [Method for Manufacturing Photomask Blanks 100] There are no particular limitations on the method for manufacturing the photomask blanks 100, and a general-purpose method can be used. For example, the photomask blanks 100 may be manufactured by depositing the halftone layer 20 and the binary layer 30 on the substrate 10 using reactive sputtering, which will be described later in FIG. 5 and in the Examples.

[0028] 5 is a schematic diagram showing a manufacturing apparatus 500 for manufacturing photomask blanks 100 according to this embodiment, and is a diagram showing the interior of the manufacturing apparatus 500 as viewed from above. The manufacturing apparatus 500 shown in Fig. 5 is an in-line sputtering apparatus, and includes a load chamber 501 for loading a substrate 10 for manufacturing the photomask blanks 100, a first sputtering chamber 502, a buffer chamber 503, a second sputtering chamber 504, and an unloading chamber 505 for unloading the manufactured photomask blanks 100.

[0029] Substrate tray P is a frame-shaped tray capable of placing substrate 10 on which half-tone layer 20 and binary layer 30 are to be formed, and substrate 10 is placed while its outer edge is supported. Substrate 10 is placed on substrate tray P so that the surface on which half-tone layer 20 and binary layer 30 are to be formed faces downward (facing downward). In manufacturing apparatus 500, as will be described later, half-tone layer 20 is formed on the surface of substrate 10 by transporting substrate tray P on which substrate 10 is placed to the position of buffer chamber 503 in the direction indicated by solid arrow Q in FIG. 5 while maintaining the surface of substrate 10 facing the target.

[0030] Thereafter, the substrate tray P is further transported from the buffer chamber 503 to the position of the unloading chamber 505 as shown by the dotted arrow R, whereby a binary layer 30 is formed on the halftone layer 20, and a photomask blank 100 is manufactured.

[0031] Loading chamber 501, first sputtering chamber 502, buffer chamber 503, second sputtering chamber 504, and unloading chamber 505 are each separated by a shutter (not shown). Loading chamber 501, first sputtering chamber 502, buffer chamber 503, second sputtering chamber 504, and unloading chamber 505 are each connected to an exhaust device (not shown), and the inside of each chamber is evacuated.

[0032] A first target 506 is provided inside first sputtering chamber 502, and a second target 507 is provided inside second sputtering chamber 504. First target 506 is preferably a metal such as zirconium, and second target 507 is preferably a metal such as chromium. DC power supplies (not shown) are provided in first sputtering chamber 502 and second sputtering chamber 504, respectively, and supply power to first target 506 and second target 507, respectively.

[0033] The first sputtering chamber 502 is provided with a first gas inlet 508 for introducing a sputtering gas into the first sputtering chamber 502. For example, the first target 506 is a sputtering target for forming a Zr-based film, and is made of a material containing zirconium (Zr). Specifically, the first target 506 is made of a material selected from zirconium, zirconium oxide, zirconium nitride, zirconium carbide, etc. For example, the sputtering gas introduced from the first gas inlet 508 is a gas for forming a Zr-based film, and may be an inert gas (argon gas, etc.) or a mixed gas of a nitrogen-containing gas and an inert gas (argon gas, etc.). In this case, the proportion of nitrogen in the sputtering gas (N ２ The gas ratio may be 0 to 3% in terms of flow rate percentage (flow %).

[0034] The second sputtering chamber 504 is provided with a second gas inlet 509 for introducing a sputtering gas into the second sputtering chamber 504. For example, the second target 507 is a sputtering target for forming a chromium compound layer and is made of a material containing chromium. Specifically, the second target 507 is made of a material selected from chromium, chromium oxide, chromium nitride, chromium carbide, etc. For example, the sputtering gas introduced from the second gas inlet 509 is a gas for forming a Cr-based film, and may be an inert gas (such as argon gas) or a mixed gas of a nitrogen- or oxygen-containing gas and an inert gas (such as argon gas).

[0035] Substrate 10 is transferred to first sputtering chamber 502, where half-tone layer 20 is formed on the surface of substrate 10 by sputtering. Furthermore, substrate 10 with half-tone layer 20 formed thereon may be transferred multiple times between buffer chamber 503 and load chamber 501 (solid line arrow Q) to perform multiple sputtering operations in first sputtering chamber 502, thereby laminating half-tone layer 20. Substrate 10 is then transferred to second sputtering chamber 504. In second sputtering chamber 504, binary layer 30 is formed on the surface of half-tone layer 20 by sputtering. Similar to half-tone layer 20, binary layer 30 may also be transferred multiple times between buffer chamber 503 and load chamber 505 (dotted line arrow R) to perform multiple sputtering operations in second sputtering chamber 504, thereby laminating binary layer 30. In this manner, the halftone layer 20 and the binary layer 30 are sequentially formed on the surface of the substrate 10, and the photomask blank 100 is manufactured.

[0036] The materials of the first and second targets 506, 507 and the type of gas introduced through the first and second gas inlets 508, 509 are selected appropriately depending on the metal material and composition used. The first and second targets 506, 507 are preferably made of different materials. For example, by using different materials for the binary layer 30 and the halftone layer 20, it is not necessary to provide an etching stopper layer between the binary layer 30 and the halftone layer 20. Furthermore, the first target is preferably zirconium, and the second target is preferably chromium. The sputtering method may be DC sputtering, RF sputtering, ion beam sputtering, or any other method.

[0037] [Method for Manufacturing Photomask 200] The method for manufacturing photomask 200 is not particularly limited, and a general-purpose method can be used. For example, photomask 200 may be manufactured using photomask blanks 100 by reactive sputtering and wet etching (see FIG. 3 ), which will be described in the examples below. Furthermore, when photomask 200 is manufactured using photomask blanks 100 in which half-tone layer 20 and binary layer 30 are made of different materials, it is not necessary to consider the amount of side etching of half-tone layer 20 when etching binary layer 30.

[0038] 3A and 3B are diagrams illustrating a method for manufacturing a photomask 200 according to this embodiment. A method for forming a pattern 50 in the binary layer 30 and a pattern 51 in the halftone layer 20 of the photomask blank 100 will be described below.

[0039] First Step: A photoresist layer 40 is formed on the photomask blank 100 (FIG. 3: Step A). ​​The thickness of the photoresist layer 40 is not particularly limited and may be set appropriately.

[0040] The photoresist layer 40 is exposed using a light-shielding mask having openings formed therein corresponding to the pattern 50. As a result, the portions of the photoresist layer 40 corresponding to the pattern 50 are exposed.

[0041] The pattern 50 is formed in the binary layer 30 by wet-etching the binary layer 30 with a first etching solution using the photoresist layer 40, in which openings corresponding to the pattern 50 have been formed, as a mask (FIG. 3: Step B). The etching temperature and etching time are not particularly limited and can be set appropriately. Thereafter, the photoresist layer 40 is stripped.

[0042] The first etching solution is different from the second etching solution described below, and is preferably an etching solution containing ceric ammonium nitrate and nitric acid.

[0043] Second Step Next, a photoresist layer 41 is formed on the uppermost surface (FIG. 3: Step C). The thickness of the photoresist layer 41 is not particularly limited and may be set appropriately.

[0044] The photoresist layer 41 is exposed using a light-shielding mask having openings formed therein corresponding to the pattern 51. As a result, the portions of the photoresist layer 41 corresponding to the pattern 51 are exposed.

[0045] Using photoresist layer 41 and binary layer 30 as a mask, half-tone layer 20 is wet-etched with a second etching solution, thereby forming pattern 51 in half-tone layer 20 ( FIG. 3 : Step D). The etching temperature and etching time are not particularly limited and may be set appropriately. Note that over-etching may be performed to remove exposed half-tone layer 20 uniformly and completely. For example, when performing 20% ​​over-etching, the time required to remove half-tone layer 20 is defined as the reference time, and etching is performed for 120% of the reference time.

[0046] The second etching solution is different from the first etching solution, and is preferably an etching solution containing ammonium fluoride.

[0047] Finally, the photoresist layer 41 is stripped off to produce the photomask 200 (FIG. 3: Step E).

[0048] [Uses of Photomask 200] Exposure Method An exposure method using the photomask 200 can be carried out as a photolithography process using an exposure apparatus in the manufacture of devices such as semiconductors and liquid crystal panels.

[0049] As shown in FIG. 4, the exposure apparatus 400 used in the exposure method includes a light source LS, an illumination optical system 402, a mask stage 403 that holds the photomask 200, a projection optical system 404, a substrate stage 405 that holds a photosensitive substrate 415 that is the object to be exposed, and a drive mechanism 406 that moves the substrate stage 405 in a horizontal plane.

[0050] First, the photomask 200 is placed on the mask stage 403 of the exposure apparatus 400. A photosensitive substrate 415 coated with photoresist is placed on the substrate stage 405. Then, exposure light is emitted from the light source LS. The emitted exposure light enters the illumination optical system 402, where it is adjusted to a predetermined luminous flux, and is then irradiated onto the photomask 200 held on the mask stage 403. The light that passes through the photomask 200 has the same pattern as the device patterns 50, 51 drawn on the photomask 200, and this pattern is irradiated via the projection optical system 404 onto a predetermined position on the photosensitive substrate 415 held on the substrate stage 405. As a result, the photosensitive substrate 415 is exposed to the device pattern of the photomask 200 at a predetermined magnification.

[0051] The photomask 200 according to this embodiment has high pattern accuracy, so by performing exposure using the photomask 200, it is possible to reduce circuit pattern defects in the exposure process, and to efficiently manufacture highly integrated devices.

[0052] Furthermore, by using halftone layer 20 as a phase shift layer, photomask blank 100 may be used as a phase shift mask blank, and photomask 200 may be used as a phase shift mask.

[0053] The photomask blanks and photomasks will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples and comparative examples.

[0054] [Manufacturing of Photomask Blanks 100] The photomask blanks 100 shown in FIG. 1 were manufactured by sequentially depositing the halftone layer 20 and the binary layer 30 on the substrate 10 according to the following procedure.

[0055] Examples 1 to 3 A circular parallel plate made of quartz glass was prepared as the substrate 10 (size: diameter 3 inches, thickness 0.5 mm). A DC magnetron sputtering device (ILC-702 Canon Anelva) was used, and a Zr alloy target (Zr purity 99.9%) was used as the sputtering target. ２ Gas ratio (flow rate %): Ar-N ２ While introducing the mixed gas, reactive sputtering was performed so that the N content (atomic %) of half-tone layer 20 was 18.5% and the film thicknesses were 36.3 nm, 21.5 nm, and 11.7 nm, respectively, to form a Zr-based half-tone layer that would become half-tone layer 20 on substrate 10 (Table 1, FIG. 6). The pressure inside the chamber was 0.2 to 1.0 Pa, and the power applied to the target was 0.5 kW.

[0056] Examples 4 to 7 and Comparative Examples 1 to 3 A circular parallel plate made of quartz glass was prepared as the substrate 10 (size: diameter 3 inches, thickness 0.5 mm). A DC magnetron sputtering device (ILC-702 Canon Anelva) was used, and a Zr alloy target (Zr purity 99.9%) was used as the sputtering target. ２ Gas ratio (flow rate %): Ar gas or Ar-N ２ While introducing the mixed gas, reactive sputtering was performed so that the thicknesses of half-tone layer 20 were 42.0 nm, 20.9 nm, 21.5 nm, 24.0 nm, 18.0 nm, 8.7 nm, and 8.4 nm, respectively, to form a Zr-based half-tone layer that would become half-tone layer 20 on substrate 10 (Table 2, FIG. 7). The pressure inside the chamber was 0.2 to 1.0 Pa, and the power applied to the target was 0.5 kW.

[0057] Comparative Examples 4 to 7 A circular parallel plate made of quartz glass was prepared as the substrate 10 (size: diameter 3 inches, thickness 0.5 mm). A DC magnetron sputtering device (ILC-702 Canon Anelva) was used, and a MoSi alloy target (atomic ratio: Mo:Si=1:4) was used as the sputtering target. ２ Gas ratio (flow rate %): Ar gas or Ar-N ２ While introducing the mixed gas, reactive sputtering was performed so that the film thickness of half-tone layer 20 became 10.1 nm, 38.3 nm, 47.7 nm, and 69.6 nm, thereby depositing a MoSi-based half-tone layer that would become half-tone layer 20 on substrate 10 (Table 3, FIG. 8). The pressure inside the chamber was 0.2 to 1.0 Pa, and the power applied to the target was 0.5 kW.

[0058] On the halftone layer 20 formed as described above, a DC magnetron sputtering apparatus (ILC-702 Canon Anelva) was used, and a Cr target was used as the sputtering target. ２ Gas ratio (flow rate %): Ar gas or Ar-N ２ Reactive sputtering was carried out while introducing the mixed gas, thereby forming a binary layer 30 on the halftone layer 20, completing a photomask blank 100 (FIG. 1).

[0059] [Manufacturing of Photomask 200] For the above photomask blank 100, a pattern 50 was formed in the binary layer 30 and a pattern 51 was formed in the halftone layer 20 as follows, and the photomask 200 shown in FIG. 2 was manufactured by the procedure shown in FIG. 3.

[0060] First, a positive ultraviolet resist (GRX-M237, manufactured by Nagase ChemteX) was applied by spin coating onto the photomask blank 100 to form a photoresist layer 40 (FIG. 3: Step A). ​​The thickness of the photoresist layer 40 was 660 nm.

[0061] Using a mask aligner (PLA-501, manufactured by Canon) with a high-pressure mercury lamp, the photoresist layer 40 was exposed using a light-shielding mask in which openings corresponding to the pattern 50 were formed. As a result, the portions of the photoresist layer 40 corresponding to the pattern 50 were exposed.

[0062] The exposed photomask blank 100 was immersed in an organic alkaline developer (1.83% tetramethylammonium hydroxide, manufactured by Tama Chemicals Co., Ltd.). This dissolved and removed the exposed portions of the photoresist layer 40, forming openings corresponding to the pattern 50. Using the photoresist layer 40 with the openings corresponding to the pattern 50 as a mask, the binary layer 30 was wet-etched using a first etching solution (PureEtchCR101, manufactured by Hayashi Pure Chemical Industries, Ltd.) containing ceric ammonium nitrate and nitric acid. The etching solution temperature was 23±3°C, and the etching time was 80 seconds. This removed the exposed portions of the binary layer 30 that were not covered by the photoresist layer 40, forming the pattern 50 ( FIG. 3 : Step B). The photoresist layer 40 was then stripped using a resist stripper (CleanThrough KS-7008B, manufactured by Kao Corporation).

[0063] Next, a positive ultraviolet resist (GRX-M237, manufactured by Nagase ChemteX) was applied to the uppermost surface by spin coating to form a photoresist layer 41 (FIG. 3: Step C). The thickness of the photoresist layer 41 was 660 nm.

[0064] Using a mask aligner (PLA-501, manufactured by Canon) with a high-pressure mercury lamp, the photoresist layer 41 was exposed using a light-shielding mask having openings formed therein corresponding to the pattern 51. As a result, the portions of the photoresist layer 41 corresponding to the pattern 51 were exposed.

[0065] The exposed portion of photoresist layer 41 was removed, and halftone layer 20 was wet-etched using photoresist layer 41 and binary layer 30 as a mask with a second etching solution containing ammonium fluoride (ADEKA Chelmica WGM-155, manufactured by ADEKA). The etching solution temperature was set to 23±3°C, and 20% overetching was performed to uniformly and completely remove the exposed halftone layer 20. This resulted in forming pattern 51 in halftone layer 20 (FIG. 3: Step D). Finally, photoresist layer 41 was stripped using a resist stripper (Kao CleanThru KS-7008B). Through the above steps, photomask 200 shown in FIG. 3, Step E, was obtained from photomask blank 100.

[0066] [Evaluation of Physical Properties of Halftone Layer 20] The film thickness and transmittance were measured for halftone layer 20 of each example and comparative example. The difference between the measured transmittance of light with a wavelength of 365 nm and the transmittance of light with a wavelength of 436 nm was calculated as a value indicating transmittance flatness. The measurement results are shown in Tables 1 to 3 and Figures 6 to 9. Note that transmittance refers to external transmittance that also takes reflection into consideration.

[0067]

[0068]

[0069]

[0070] As shown in Tables 1 and 2 and FIG. ２ When the gas ratio (flow rate %) was set to 0 to 3%, good transmittance flatness was confirmed. ２ Even when manufactured with the gas ratio (flow rate %), good transmittance flatness was not confirmed.

[0071] By fabricating a half-tone layer made of a material different from that of the binary layer, the conventional etching stopper is no longer necessary, which eliminates the need for an etching stopper film formation step in the film formation process and an etching stopper treatment step in the mask manufacturing process, thereby shortening the process.

[0072] 10 Substrate 20 Halftone layer 30 Binary layer 40 First photoresist layer 41 Second photoresist layer 50 Binary layer pattern 51 Halftone layer pattern 100 Photomask blank 200 Photomask 400 Exposure apparatus LS Light source 402 Illumination optical system 404 Projection optical system 403 Mask stage 405 Substrate stage 500 Manufacturing apparatus P Substrate tray Q Solid arrow R Dotted arrow 501 Loading chamber 502 First sputtering chamber 503 Buffer chamber 504 Second sputtering chamber 505 Unloading chamber 506 First target 507 Second target 508 First gas inlet 509 Second gas inlet

Claims

1. A photomask blank having a first layer and a second layer on a substrate, The first layer is on the substrate; the second layer is on the first layer; The photomask blanks, wherein the first layer contains zirconium in an atomic composition percentage (atomic %) of 60% to 99.5%.

2. the first layer is a halftone layer; The photomask blank of claim 1 , wherein the second layer is a binary layer.

3. 3. The photomask blank according to claim 2, wherein a difference between a transmittance of light having a wavelength of 365 nm transmitted through said first layer and a transmittance of light having a wavelength of 436 nm transmitted through said first layer is 1.5% or less.

4. The photomask blank according to claim 3 , wherein the transmittance is an external transmittance.

5. The photomask blank according to any one of claims 1 to 4, wherein the second layer contains chromium.

6. A photomask blank having a first layer and a second layer on a substrate, The first layer is on the substrate; the second layer is on the first layer; the first layer is a half-tone layer, contains a metal other than chromium, and has a difference of 1.5% or less between a transmittance of light having a wavelength of 365 nm transmitted through the first layer and a transmittance of light having a wavelength of 436 nm transmitted through the first layer; the second layer is a binary layer and comprises chromium.

7. The photomask blank according to claim 6 , wherein the transmittance is an external transmittance.

8. The photomask blank according to claim 6 or 7, wherein the first layer contains zirconium.

9. The photomask blank according to claim 8 , wherein the first layer contains zirconium in an atomic composition percentage (atomic %) of 60% to 99.5%.

10. The photomask blank according to any one of claims 1 to 4, 6 and 7, wherein the first layer contains nitrogen.

11. The photomask blank according to any one of claims 1 to 4, 6 and 7, wherein the first layer contains nitrogen in an atomic composition percentage (atomic %) of 0% to 30%.

12. 8. The photomask blank according to claim 1, wherein the transmittance of light having a wavelength of 365 nm to 436 nm transmitted through the first layer is 5% or more and 50% or less.

13. The photomask blank according to any one of claims 1 to 4, 6 and 7, wherein the second layer is in contact with the first layer.

14. A photomask blank having a first layer and a second layer on a substrate, The first layer is on the substrate; the second layer is on and in contact with the first layer; The photomask blank, wherein the first layer comprises zirconium.

15. The method of claim 1, wherein the first layer is a halftone layer; The photomask blank of claim 14 , wherein the second layer is a binary layer.

16. A photomask blank as described in claim 14 or 15, wherein the second layer contains chromium.

17. The photomask blank according to any one of claims 1 to 4, 6, 7, 14 and 15, wherein the first layer has a thickness of 5 nm or more and 45 nm or less.

18. The photomask blank according to any one of claims 1 to 4, 6, 7, 14 and 15, wherein the first layer is used as a phase shift layer.

19. A photomask having a pattern formed on the photomask blank according to any one of claims 1 to 4, 6, 7, 14 and 15.

20. A first step of etching the second layer of the photomask blank according to any one of claims 1 to 4, 6, 7, 14, and 15 to form a second layer pattern in the second layer; a second step of etching the first layer to form a first layer pattern in the first layer that is different from the second layer pattern.

21. In the first step, the second layer is etched using a first etching solution to form the second layer pattern on the second layer; 21. The method for manufacturing a photomask according to claim 20, wherein in the second step, the first layer is etched using a second etching liquid different from the first etching liquid, thereby forming the first layer pattern in the first layer.

22. A method for manufacturing a device, comprising a step of exposing a pattern onto a workpiece using the photomask described in claim 19.

23. A method for manufacturing a photomask blank by forming a first layer and a second layer on a substrate, comprising: a first layer deposition step of depositing a first layer on the substrate while introducing a gas; a second layer deposition step of depositing a second layer on the first layer, The method for producing a photomask blank, wherein the proportion of nitrogen in the gas is 0% or more and 3% or less in terms of flow rate percentage (flow rate %).

24. 24. The method for producing a photomask blank according to claim 23, wherein in the second layer deposition step, the second layer is deposited on the first layer so as to be in contact with the first layer.

25. the first layer includes a metal other than chromium; The method for producing a photomask blank according to claim 23 or 24, wherein the second layer contains chromium.

26. 25. The method for producing a photomask blank according to claim 23, wherein the first layer contains zirconium in an atomic composition percentage (atomic %) of 60% to 99.5%.

27. 25. The method for producing a photomask blank according to claim 23, wherein the first layer is used as a phase shift layer.

28. the first layer is a halftone layer; 25. The method for producing a photomask blank according to claim 23 or 24, wherein the second layer is a binary layer.

29. A method for manufacturing a photomask, using a photomask blank manufactured by the method for manufacturing a photomask blank according to claim 23 or 24.

30. 30. A method for manufacturing a device, comprising an exposure step of exposing a pattern onto an object to be processed using a photomask manufactured by the method for manufacturing a photomask according to claim 29.