Blank mask and method for manufacturing blank mask

Abstract

To provide a blank mask from which a photomask that is precisely patterned and has less optical strains can be provided, and a method for manufacturing the same.SOLUTION: A blank mas includes a light-transmitting substrate, an optical substrate which is arranged on the light-transmitting substrate and includes a light-shielding film, and a photoresist layer arranged on the optical substrate, wherein the photoresist layer includes 49 regions which are divided into 7 at equal intervals in a lateral direction and divided into 7 at equal intervals in a longitudinal direction, the 49 regions include a first region corresponding to the center of the optical substrate, a second region arranged along the periphery of the first region, a third region arranged along the periphery of the second region, and a fourth region corresponding to the contour of the optical substrate, and the density of the optical unevenness in the fourth region is larger than the density of the optical unevenness in the first region, the second region and the third region.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The embodiments relate to a blank mask and a method for manufacturing the blank mask.

Background Art

[0002] Due to the high integration of semiconductor devices and the like, miniaturization of the circuit patterns of semiconductor devices is required. As a result, the importance of lithography technology, which is a technique for developing circuit patterns on the wafer surface using a photomask, is further emphasized.

[0003] In order to develop miniaturized circuit patterns, a shorter wavelength of the exposure light source used in the exposure process is required. In recent years, among the exposure light sources used, there is an ArF excimer laser (wavelength 193 nm) and the like.

[0004] On the other hand, photomasks include a binary mask and a phase shift mask.

[0005] The binary mask has a configuration in which a light-shielding layer pattern is formed on a light-transmissive substrate. In the binary mask, on the surface where the pattern is formed, a transmissive portion that does not include the light-shielding layer transmits exposure light, and a light-shielding portion that includes the light-shielding layer blocks the exposure light, thereby exposing a pattern on the resist film on the wafer surface. However, in the binary mask, as the pattern becomes more miniaturized, problems may occur in the development of fine patterns due to the diffraction of light generated at the edge of the transmissive portion in the exposure process.

[0006] In phase shift masks, there are the Levenson type, the Outrigger type, and the Half-tone type. Among them, the half-tone type phase shift mask has a configuration in which a pattern formed of a semi-transmissive film is formed on a light-transmissive substrate 20. The half-tone type phase shift mask, on the surface where the pattern is formed, a transmissive portion that does not include a semi-transmissive layer transmits exposure light, and a semi-transmissive portion that includes a semi-transmissive layer transmits the attenuated exposure light. The attenuated exposure light comes to have a phase difference compared with the exposure light that has passed through the transmissive portion. Thereby, the diffracted light generated at the edge of the transmissive portion is canceled out by the exposure light that has passed through the semi-transmissive portion, and the phase shift mask can form a more delicate fine pattern on the wafer surface.

Prior Art Documents

Patent Documents

[0007] The prior documents related to this are as follows.

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] An embodiment aims to provide a blank mask that can be precisely patterned and provide a photomask with little optical distortion, and a method for manufacturing the same.

Means for Solving the Problems

[0009] The blank mask according to the embodiment includes a light-transmissive substrate, a light-shielding film disposed on the light-transmissive substrate, and a photoresist layer disposed on the light-shielding film. The photoresist layer includes 49 regions divided into 7 regions at equal intervals in the horizontal direction and divided into 7 regions at equal intervals in the vertical direction, and the thickness deviation in the 49 regions is less than 100 Å.

[0010] In the blank mask according to an embodiment, the 49 regions include a first region corresponding to the center of the optical substrate, a second region disposed along the periphery of the first region, a third region disposed along the periphery of the second region, and a fourth region corresponding to the outer contour of the optical substrate. The average thickness in the fourth region may be even greater than the average thickness in the third region.

[0011] In the blank mask according to an embodiment, the average thickness in the fourth region may be even greater by about 3 Å to about 10 Å than the average thickness in the third region.

[0012] In the blank mask according to an embodiment, the average thickness in the fourth region may be even greater than the average thickness in the second region.

[0013] In the blank mask according to an embodiment, the average thickness in the first region may be even greater than the average thickness in the second region.

[0014] In the blank mask according to an embodiment, the average thickness in the first region may be even greater than the average thickness in the third region.

[0015] The method for manufacturing a blank mask according to an embodiment includes forming an optical substrate including a light-shielding film disposed on a transparent substrate, and forming a photoresist layer on the light-shielding film while rotating the optical substrate. The step of forming the photoresist layer includes a first rotation step of the optical substrate, a second rotation step of the optical substrate at a speed faster than the first rotation, a third rotation step of the optical substrate at a speed faster than the second rotation, a fourth rotation step of the optical substrate at a speed faster than the third rotation, a fifth rotation step of the optical substrate at a speed slower than the fourth rotation, and a sixth rotation step of the optical substrate at a speed slower than the fifth rotation.

[0016] In the method for manufacturing a blank mask according to an embodiment, the first rotation speed is 30 rpm to 70 rpm, the second rotation speed is 50 rpm to 100 rpm, the third rotation speed is 100 rpm to 150 rpm, the fourth rotation speed is 800 rpm to 3000 rpm, the fifth rotation speed is 500 rpm to 2500 rpm, and the sixth rotation speed may be 100 rpm to 500 rpm.

[0017] In the method for manufacturing a blank mask according to an embodiment, the first rotation step, the second rotation step, the third rotation step, the fourth rotation step, the fifth rotation step, and the sixth rotation step can be performed at a temperature of 20°C to 30°C.

[0018] In the method for manufacturing a blank mask according to an embodiment, the fourth rotation step can be performed for 0.5 seconds to 2 seconds.

[0019] The blank mask according to the embodiment includes a light-transmissive substrate, an optical substrate including a light-shielding film disposed on the light-transmissive substrate, and a photoresist layer disposed on the optical substrate. The photoresist layer includes 49 regions divided into 7 regions at equal intervals in the horizontal direction and divided into 7 regions at equal intervals in the vertical direction. The 49 regions include a first region corresponding to the center of the optical substrate, a second region disposed along the periphery of the first region, a third region disposed along the periphery of the second region, and a fourth region corresponding to the outer contour of the optical substrate. The density of the optical unevenness in the fourth region may be even greater than the density of the optical unevenness in the first region, the second region, and the third region.

[0020] In the blank mask according to an embodiment, the optical unevenness is detected by a laser of 532 nm and is disposed on the light-shielding film at less than 30 pieces / 36 inch. 2 It may be arranged.

[0021] In the blank mask according to an embodiment, the density of the optical unevenness in the fourth region may be 15 pieces / 36 inch 2 ~25 pieces / 36 inch 2 It may be.

[0022] In the blank mask according to an embodiment, the density of the optical unevenness in the first region, the second region, and the third region may be 5 pieces / 36 inch 2 ~20 pieces / 36 inch 2 It may be.

[0023] In the blank mask according to an embodiment, the diameter of the optical unevenness may be 10 nm to 500 nm.

[0024] In the blank mask according to an embodiment, the difference between the density of the optical unevenness in the fourth region and the density of the optical unevenness in the first region, the second region, and the third region may be 1 piece / 36 inch 2 ~15 pieces / 36 inch 2 It may be.

[0025] In a blank mask according to an embodiment, the number of optical irregularities in each of the fourth regions may be three or less.

[0026] In a blank mask according to an embodiment, the photoresist layer may include a flat portion disposed on the light-shielding portion, and the optical irregularities may have an optical thickness different from that of the light-shielding portion.

[0027] In a blank mask according to an embodiment, the optical irregularities may include a light path changing portion.

[0028] In a blank mask according to an embodiment, the light path changing portion is a blank mask having a refractive index different from that of the flat portion.

[0029] A method for manufacturing a semiconductor device according to an embodiment includes preparing a blank mask including an optical substrate and a photoresist layer disposed on the optical substrate, forming a photomask using the blank mask, and patterning a semiconductor substrate using the photomask. The optical substrate includes a light-transmissive substrate and a light-shielding film disposed on the light-transmissive substrate. The photoresist layer includes 49 regions divided into 7 regions at equal intervals in the horizontal direction and 7 regions at equal intervals in the vertical direction. The 49 regions include a first region corresponding to the center of the optical substrate, a second region disposed along the periphery of the first region, a third region disposed along the periphery of the second region, and a fourth region corresponding to the outer contour of the optical substrate. The density of optical irregularities in the fourth region is further greater than the density of optical irregularities in the first region, the second region, and the third region.

[0030] A blank mask according to an embodiment includes a light-transmissive substrate, a light-shielding film disposed on the light-transmissive substrate, and a photoresist layer disposed on the light-shielding film. The photoresist layer includes 49 regions divided into 7 regions at equal intervals in the horizontal direction and 7 regions at equal intervals in the vertical direction. The thickness deviation in the 49 regions may be less than 100 Å.

[0031] In a blank mask according to an embodiment, the 49 regions include a first region corresponding to the center of the optical substrate, a second region arranged along the periphery of the first region, a third region arranged along the periphery of the second region, and a fourth region corresponding to the outer contour of the optical substrate, and the average thickness in the fourth region may be even greater than the average thickness in the third region.

[0032] In a blank mask according to an embodiment, the average thickness in the fourth region may be about 3 Å to about 10 Å greater than the average thickness in the third region.

[0033] In a blank mask according to an embodiment, the average thickness in the fourth region may be even greater than the average thickness in the second region.

[0034] In a blank mask according to an embodiment, the average thickness in the first region may be even greater than the average thickness in the second region.

[0035] In a blank mask according to an embodiment, the average thickness in the first region may be even greater than the average thickness in the third region.

[0036] A method for manufacturing a blank mask according to an embodiment includes forming an optical substrate including a light-shielding film disposed on a transparent substrate, and forming a photoresist layer on the light-shielding film while rotating the optical substrate. The step of forming the photoresist layer includes rotating the optical substrate for a first rotation, rotating the optical substrate for a second rotation at a speed faster than the first rotation, rotating the optical substrate for a third rotation at a speed faster than the second rotation, rotating the optical substrate for a fourth rotation at a speed faster than the third rotation, rotating the optical substrate for a fifth rotation at a speed slower than the fourth rotation, and rotating the optical substrate for a sixth rotation at a speed slower than the fifth rotation.

[0037] In the method for manufacturing a blank mask according to an embodiment, the first rotation speed is 30 rpm to 70 rpm, the second rotation speed is 50 rpm to 100 rpm, the third rotation speed is 70 rpm to 150 rpm, the fourth rotation speed is 800 rpm to 3000 rpm, the fifth rotation speed is 500 rpm to 2500 rpm, and the sixth rotation speed may be 100 rpm to 500 rpm.

[0038] In the method for manufacturing a blank mask according to an embodiment, the first rotation stage, the second rotation stage, the third rotation stage, the fourth rotation stage, the fifth rotation stage, and the sixth rotation stage can be performed at a temperature of 20°C to 30°C.

[0039] In the method for manufacturing a blank mask according to an embodiment, the fourth rotation stage can be performed for 0.5 seconds to 2 seconds.

Advantages of the Invention

[0040] The blank mask according to the embodiment may include a photoresist layer with a high thickness uniformity as a whole. As a result, the photoresist layer can be precisely patterned in the exposure and development processes. As a result, the blank mask according to the embodiment can precisely pattern the light-shielding film and provide a precise photomask.

[0041] In particular, in the blank mask according to the embodiment, the photoresist layer may have a relatively thicker outer peripheral region. That is, the process conditions are adjusted so that the outer peripheral region of the photoresist layer is formed relatively thicker, and the photoresist layer may have a uniform thickness as a whole.

[0042] Also, the process for forming the photoresist layer may include first to sixth rotation steps. As a result, the photoresist layer may have a uniform thickness as a whole. Also, the photoresist layer may have a relatively slightly thicker outer peripheral region when formed by the above process.

[0043] Also, the photoresist layer may include optical unevenness. In particular, the photoresist layer may be formed such that the optical density of the outer peripheral region is even higher. As a result, the photoresist layer can reduce the number of optical unevenness as a whole.

[0044] In particular, the blank mask according to the embodiment may include the optical unevenness at less than 30 pieces / 36 inches. 2 and may include the optical unevenness.

[0045] As a result, the manufacturing method of the blank mask according to the embodiment can realize a photoresist layer having optical flatness as a whole. As a result, the photoresist layer can precisely pattern the light-shielding film.

[0046] In particular, since the photoresist layer has the optical unevenness detected by a laser of 532 nm in the above number as described above, it can be precisely developed by ultraviolet light.

[0047] As a result, the blank mask according to the embodiment can provide a photomask having a precise pattern.

[0048] In particular, in the blank mask according to the embodiment, the photoresist layer may have a relatively thicker outer peripheral region. That is, the process conditions are adjusted such that the outer peripheral region of the photoresist layer is formed relatively slightly thicker, and the photoresist layer may have a uniform thickness as a whole.

[0049] In addition, the process for forming the photoresist layer may include first to sixth rotation steps. As a result, the photoresist layer may have a uniform thickness as a whole. Further, since the photoresist layer is formed by the above process, it may also have a relatively thicker outer peripheral region.

[0050] In addition, the photoresist layer may include optical irregularities. In particular, the optical density of the outer peripheral region of the photoresist layer may be formed to be even higher. As a result, the total number of optical irregularities of the photoresist layer can be reduced.

[0051] In particular, the blank mask according to the embodiment may include the optical irregularities at less than 30 per 36 inches. 2 and less than that may include the optical irregularities.

[0052] As a result, the method for manufacturing a blank mask according to the embodiment can implement a photoresist layer having optical flatness as a whole. As a result, the photoresist layer can precisely pattern the light-shielding film.

[0053] In particular, since the photoresist layer has the optical irregularities detected by a laser of 532 nm in the above number as described above, it can be precisely developed by ultraviolet light.

[0054] As a result, the blank mask according to the embodiment can provide a photomask having a precise pattern.

Brief Description of Drawings

[0055]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0056] Hereinafter, the embodiments will be described in detail so that those having ordinary knowledge in the technical field to which the embodiments belong can easily implement them. However, the embodiments can be embodied in various forms that are different from each other and are not limited to the embodiments described here.

[0057] Terms such as "about" and "substantially" as used in this specification are used in or near that numerical value when manufacturing and material tolerances inherent in the recited meaning are presented, and are used to prevent the disclosure content in which an exact or absolute numerical value is recited for understanding the embodiments from being misused by unscrupulous infringers.

[0058] Throughout this specification, the term "these combinations" included in the Markush-type expressions means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expressions, and means including one or more selected from the group consisting of the above components.

[0059] Throughout this specification, the description "A and / or B" means "A, B, or A and B".

[0060] Throughout this specification, terms such as "first", "second" or "A", "B" are used to distinguish the same terms from each other unless otherwise specified.

[0061] In this specification, the meaning that B is located on A means that B is located on A, or B may be located on A while another layer is located therebetween, and is not construed as being limited to B being located in contact with the surface of A.

[0062] In this specification, a singular expression is construed to have a meaning including the singular or plural as construed in the context unless otherwise specified.

[0063] FIG. 1 is a cross-sectional view showing a cross-section of an optical substrate according to one embodiment. FIG. 2 is a cross-sectional view showing a cross-section of an optical substrate according to another embodiment. FIG. 3 is a cross-sectional view showing a cross-section of an optical substrate according to still another embodiment. FIG. 4 is a schematic view showing a manufacturing apparatus for a blank mask according to an embodiment. FIG. 5 is a cross-sectional view showing a cross-section of a blank mask according to an embodiment. FIG. 6 is an enlarged cross-sectional view showing a cross-section of a blank mask according to an embodiment. FIG. 7 is a plan view showing a photoresist layer divided into 49 regions. FIG. 8 is a cross-sectional view showing a cross-section of a photomask according to one embodiment.

[0064] The blank mask according to the embodiment may be manufactured by the following manufacturing process.

[0065] First, as shown in FIGS. 1 to 3, the optical substrate 10 can be provided. The optical substrate 10 includes a light-transmissive substrate 20 and a light-shielding film 30 located on the light-transmissive substrate 20.

[0066] The light-transmissive substrate 20 may have light transmissivity with respect to exposure light. The light-transmissive substrate 20 may have a transmittance of more than about 85% with respect to exposure light having a wavelength of about 193 nm. The transmittance of the light-transmissive substrate 20 may be more than about 87%. The transmittance of the light-transmissive substrate 10 may be less than 99.99%. The light-transmissive substrate 20 may include a synthetic quartz substrate. In such a case, the light-transmissive substrate 20 can suppress attenuation of the transmitted light.

[0067] Since the light-transmissive substrate 20 has surface characteristics such as appropriate flatness and appropriate illuminance, it is possible to suppress distortion of the transmitted light.

[0068] The light-shielding film 30 may be disposed on the top side of the light-transmissive substrate 20.

[0069] The light-shielding film 30 can at least selectively block exposure light incident on the bottom side of the light-transmissive substrate 20.

[0070] Also, as shown in FIG. 3, when a phase shift film 40 or the like is disposed between the light-transmissive substrate 20 and the light-shielding film 30, the light-shielding film 30 can be used as an etching mask in the process of etching the phase shift film 40 or the like in accordance with the pattern shape.

[0071] The light-shielding film 30 may contain at least any one of a transition metal, oxygen, and nitrogen.

[0072] The light-shielding film 30 may contain chromium, oxygen, nitrogen, and carbon. The elemental content by element with respect to the entire light-shielding film 30 may differ in the thickness direction. The elemental content by element with respect to the entire light-shielding film 30 may differ by layer in the case of a multi-layer light-shielding film 30.

[0073] The light-shielding film 30 may contain chromium in a content of about 44 atom% to about 60 atom%. The light-shielding film 30 may contain chromium in a content of about 47 atom% to about 57 atom%.

[0074] The light-shielding film 30 may contain carbon in a content of about 5 atom% to 30 atom%. The light-shielding film 30 may contain carbon in a content of about 7 atom% to about 25 atom%.

[0075] The light-shielding film 30 may contain nitrogen in a content of about 3 atom% to about 20 atom%. The light-shielding film 30 may contain nitrogen in a content of about 5 atom% to about 15 atom%.

[0076] The light-shielding film 30 may contain oxygen in a content of about 20 atom% to about 45 atom%. The light-shielding film 30 may contain oxygen in a content of about 25 atom% to about 40 atom%.

[0077] In such a case, the light-shielding film 30 may have sufficient light extinction characteristics.

[0078] As shown in FIG. 2, the light-shielding film 30 may include a first light-shielding layer 31 and a second light-shielding layer 32 disposed on the first light-shielding layer 31.

[0079] The second light-shielding layer 32 contains a transition metal. Further, the second light-shielding layer 32 may contain at least one of oxygen, nitrogen, and carbon. The second light-shielding layer 32 may contain a transition metal in a content of about 50 atom% to about 80 atom%. The second light-shielding layer 32 may contain a transition metal in a content of about 55 atom% to about 75 atom%. The second light-shielding layer 32 may contain a transition metal in a content of about 60 atom% to about 70 atom%.

[0080] The content of the element corresponding to at least one of oxygen, nitrogen, or carbon in the second light-shielding layer 32 may be about 10 atom% to about 35 atom%. The content of the element corresponding to at least one of oxygen, nitrogen, or carbon in the second light-shielding layer 32 may be about 15 atom% to about 25 atom%.

[0081] The second light-shielding layer 32 may contain nitrogen in a content of about 5 atom% to about 20 atom%. The second light-shielding layer 32 may contain nitrogen in a content of about 7 atom% to about 13 atom%.

[0082] The second light-shielding layer 32 may contain oxygen in a content of about 5 atom% to about 20 atom%. The second light-shielding layer 32 may contain oxygen in a content of about 7 atom% to about 13 atom%.

[0083] The second light-shielding layer 32 may contain carbon in a content of about 2 atom% to about 10 atom%. The second light-shielding layer 32 may contain nitrogen in a content of about 37 atom% to about 8 atom%.

[0084] The second light-shielding layer 32 may contain all of nitrogen, oxygen, and carbon.

[0085] In such a case, the light-shielding film 30 can assist in forming a laminate with the phase shift film 40 to substantially block exposure light.

[0086] The first light-shielding layer 31 may contain a transition metal. The first light-shielding layer 31 may contain oxygen and nitrogen. The first light-shielding layer 31 may contain a transition metal in an amount of 30 atom% or more and 60 atom% or less. The light-shielding layer 21 may contain a transition metal in an amount of 35 atom% or more and 55 atom% or less. The first light-shielding layer 31 may contain a transition metal in an amount of 40 atom% or more and 50 atom% or less.

[0087] The sum of the oxygen content and the nitrogen content of the first light-shielding layer 31 may be 40 atom% or more and 70 atom% or less. The sum of the oxygen content and the nitrogen content of the first light-shielding layer 31 may be 45 atom% or more and 65 atom% or less. The sum of the oxygen content and the nitrogen content of the first light-shielding layer 31 may be 50 atom% or more and 60 atom% or less.

[0088] The first light-shielding layer 31 may contain oxygen in an amount of 20 atom% or more and 40 atom% or less. The first light-shielding layer 31 may contain oxygen in an amount of 23 atom% or more and 33 atom% or less. The first light-shielding layer 31 may contain oxygen in an amount of 25 atom% or more and 30 atom% or less.

[0089] The first light-shielding layer 31 may contain nitrogen in an amount of 5 atom% or more and 20 atom% or less. The first light-shielding layer 31 may contain nitrogen in an amount of 7 atom% or more and 17 atom% or less. The first light-shielding layer 31 may contain nitrogen in an amount of 10 atom% or more and 15 atom% or less.

[0090] In such a case, the first light-shielding layer 31 can assist the light-shielding film 30 to have excellent light extinction characteristics.

[0091] The transition metal may contain at least one of Cr, Ta, Ti, and Hf. The transition metal may be Cr.

[0092] The thickness of the first light-shielding layer 31 may be about 250 Å to about 650 Å. The thickness of the first light-shielding layer 31 may be about 350 Å to about 600 Å. The thickness of the first light-shielding layer 31 may be about 400 Å to about 550 Å. In such a case, the first light-shielding layer 31 can assist the light-shielding film 30 to effectively block the exposure light.

[0093] The thickness of the second light-shielding layer 32 may be about 30 Å to about 200 Å. The thickness of the second light-shielding layer 32 may be about 30 Å or more and about 100 Å. The thickness of the second light-shielding layer 32 may be about 40 Å to about 80 Å. In such a case, the second light-shielding layer 32 can assist in improving the extinction characteristics of the light-shielding film 30 and further precisely controlling the surface profile of the side surface of the light-shielding pattern film 35 formed during patterning of the light-shielding film 30.

[0094] The ratio of the thickness of the second light-shielding layer 32 to the thickness of the first light-shielding layer 31 may be about 0.05 to about 0.3. The ratio of the thickness of the second light-shielding layer 32 to the first light-shielding layer 31 may be about 0.07 to about 0.25. The ratio of the thickness of the second light-shielding layer 32 to the first light-shielding layer 31 may be about 0.1 to about 0.2.

[0095] In such a case, the light-shielding film 30 has sufficient extinction characteristics and can further precisely control the surface profile of the side surface of the light-shielding pattern film 35 formed during patterning of the light-shielding film 30.

[0096] The content of the transition metal in the second light-shielding layer 32 may have a value even larger than the content of the transition metal in the first light-shielding layer 31.

[0097] In order to more precisely control the surface profile of the side surface of the light-shielding pattern film 35 formed by patterning the light-shielding film 30 and make the surface reflectivity of the light-shielding film 30 with respect to the inspection light in defect inspection have a value suitable for inspection, it may be required that the second light-shielding layer 32 has a value with an even larger content of transition metal with respect to the first light-shielding layer 31.

[0098] However, in such a case, during the heat treatment of the formed light-shielding film 30, the transition metal contained in the second light-shielding layer 32 may undergo recovery, recrystallization, and grain growth. When grain growth occurs in the second light-shielding layer 32 containing a high content of transition metal, the surface illuminance characteristics of the light-shielding film 30 may vary excessively due to the overgrown transition metal particles. This may cause an increase in the number of pseudo defect detections when inspecting the surface of the light-shielding film 30 with high sensitivity.

[0099] The light-shielding film 30 may have a transmittance of about 1% to about 2% with respect to light having a wavelength of 193 nm. The light-shielding film 30 may have a transmittance of about 1.3% to about 2% with respect to light having a wavelength of 193 nm. The light-shielding film 30 may have a transmittance of about 1.4% to about 2% with respect to light having a wavelength of 193 nm.

[0100] The light-shielding film 30 may have an optical density of about 1.8 to about 3. The light-shielding film 30 may have an optical density of about 1.9 to about 3.

[0101] In such a case, the thin film including the light-shielding film 30 can effectively suppress the transmission of exposure light.

[0102] As shown in FIG. 3, the optical substrate 10 may further include a phase shift film 40.

[0103] The phase shift film 40 may be disposed between the light-transmissive substrate 20 and the light-shielding film 30. The phase shift film 40 may be a thin film that attenuates the intensity of the transmitted exposure light, adjusts the phase difference, and substantially suppresses the diffracted light generated at the edge of the pattern.

[0104] The phase shift film 40 may have a phase difference of about 170° to about 190° with respect to light having a wavelength of 193 nm. The phase shift film 40 may have a phase difference of about 175° to about 185° with respect to light having a wavelength of 193 nm.

[0105] The phase shift film 40 may have a transmittance of about 3% to about 10% with respect to light having a wavelength of 193 nm. The phase shift film 40 may have a transmittance of about 4% to about 8% with respect to light having a wavelength of 193 nm. In such a case, the resolution of the photomask 200 including the phase shift film 40 can be improved.

[0106] The phase shift film 40 may contain a transition metal and silicon. The phase shift film 40 may contain a transition metal, silicon, oxygen, and nitrogen. The transition metal may be molybdenum.

[0107] A hard mask (not shown) may be located on the light shielding film 30. The hard mask can function as an etching mask film when etching the pattern of the light shielding film 30. The hard mask may contain silicon, nitrogen, and oxygen.

[0108] The method for manufacturing the optical substrate 10 includes a step of forming the light shielding film 30 on the light transmissive substrate 20. The light shielding film 30 may be formed by a sputtering process.

[0109] After the sputtering process is performed, a heat treatment process can be performed.

[0110] The heat treatment step can be performed at a temperature of about 200°C to about 400°C.

[0111] The heat treatment step can be performed for about 5 minutes to about 30 minutes.

[0112] Further, the method for manufacturing the optical substrate 10 may further include a step of cooling the light shielding film 30 that has undergone the heat treatment process.

[0113] The sputtering target can be selected in consideration of the composition of the light-shielding film 30 to be formed. As the sputtering target, a single target containing a transition metal can be applied. The sputtering target can include a single target containing a transition metal, and two or more targets can be applied. The target containing a transition metal may contain 90 atom% or more of the transition metal. The target containing a transition metal may contain 95 atom% or more of the transition metal. The target containing a transition metal may contain 99 atom% of the transition metal.

[0114] The transition metal may include at least one of Cr, Ta, Ti, and Hf. The transition metal may include Cr.

[0115] The atmospheric gas may include an inert gas, a reactive gas, and a sputtering gas. The inert gas is a gas that does not contain the elements constituting the formed thin film. The reactive gas is a gas that contains the elements constituting the formed thin film.

[0116] The sputtering gas is a gas that is ionized in a plasma atmosphere and collides with the target. The inert gas may include helium.

[0117] The reactive gas may include a gas containing a nitrogen element. Examples of the gas containing a nitrogen element may include N2, NO, NO2, N2O, N2O3, N2O4, or N2O5. The reactive gas may include a gas containing an oxygen element.

[0118] The gas containing the oxygen element may be, for example, O2. The reactive gas may contain a gas containing a nitrogen element and a gas containing an oxygen element. The reactive gas may contain a gas containing both a nitrogen element and an oxygen element. The gas containing both a nitrogen element and an oxygen element may be, for example, NO, NO2, N2O, N2O3, N2O4, or N2O5.

[0119] In addition, the reactive gas containing carbon and oxygen may be CO2.

[0120] The sputtering gas may be Ar gas.

[0121] As the power source for applying power to the sputtering target, a DC power source can be used, or an RF power source can also be used.

[0122] Thereafter, the cooled light-shielding film 30 can be washed. The washing process may include an ultraviolet irradiation process and / or a rinsing process.

[0123] The ultraviolet irradiation process may include a step of irradiating the light-shielding film 30 with ultraviolet rays.

[0124] The rinsing process includes a step of treating the light-shielding film 30 with a cleaning liquid. The cleaning liquid may contain at least one of deionized water, hydrogen water, ozone water, or carbonated water. The cleaning liquid may contain the carbonated water.

[0125] As shown in FIG. 4, a coating device is provided to form a photoresist layer 50 on the optical substrate 10. The coating device includes a chamber 100, a chuck 200, an exhaust unit 400, a supply unit 500 for a photoresist resin composition, and a spindle motor 700.

[0126] The chamber 100 houses the chuck 200. The chamber 100 can accommodate the optical substrate 10 for manufacturing a blank mask. The chamber 100 can isolate its interior from the outside. The interior of the chamber 100 can be sealed. The internal pressure of the chamber 100 can be under a vacuum lower than atmospheric pressure.

[0127] Also, the chamber 100 may include an openable door or cover. The chamber 100 may be provided with a heater or the like capable of adjusting the internal temperature of the chamber 100.

[0128] The chuck 200 may include a support portion 210 and a guide portion 220.

[0129] The support portion 210 can support the guide portion 220 and the by-product removal portion 230. The support portion 210 supports the optical substrate 10. The support portion 210 may be disposed under the optical substrate 10.

[0130] The support portion 210 can temporarily fix the optical substrate 10. The support portion 210 can temporarily fix the optical substrate 10 by vacuum pressure or electrostatic force.

[0131] The guide portion 220 may be connected to the support portion 210. The guide portion 220 may be formed integrally with the support portion 210. The guide portion 220 may be disposed on the side surface 12 of the optical substrate 10. The guide portion 220 may surround the side surface 12 of the optical substrate 10.

[0132] The support portion 210 and the guide portion 220 can form a housing portion 240 for housing the optical substrate 10. That is, the support portion 210 may be disposed on the lower surface 13 of the optical substrate 10, and the guide portion 220 may be disposed on the side surface 12 of the optical substrate 10, and the housing portion 240 may be configured.

[0133] The housing portion 240 can correspond to the planar shape of the optical substrate 10. The planar shape of the housing portion 240 may be substantially similar to the planar shape of the optical substrate 10. The planar shape of the optical substrate 10 is square, and the planar shape of the housing portion 240 may also be square.

[0134] The outer contour of the guide portion 220 may be circular. The guide portion 220 and the support portion 210 may be circular.

[0135] The exhaust portion 400 can exhaust the internal gas of the chamber 100. Further, the exhaust portion 400 can discharge the photoresist composition remaining after coating on the optical substrate 10. The exhaust portion 400 can discharge the photoresist resin composition scattered to the side of the chuck 200.

[0136] The supply portion 500 of the photoresist resin composition can supply the photoresist resin composition 510 to the upper surface of the optical substrate 10. The photoresist resin composition 510 may include an injection nozzle 520 disposed in the chamber 100. Through the injection nozzle 520, the photoresist resin composition 510 can drop onto the optical substrate 10. That is, the supply portion 500 of the photoresist resin composition can inject the photoresist resin composition 510 onto the upper surface of the optical substrate 10.

[0137] The photoresist resin composition may be a negative-type photosensitive or radiation-sensitive resin composition. The photoresist composition may be a resist composition for forming a negative-type pattern, a negative-type resist composition for organic solvent development, or a negative-type resist composition for alkali development. The photoresist resin composition may typically be a chemically amplified resist composition.

[0138] The photoresist resin composition may contain a binder resin, a photosensitizer, and an organic solvent.

[0139] Examples of the binder resin include novolak resins, phenolic resins, epoxy resins, or polyimide resins. Examples of the binder resin include polyvinyl pyrrolidone or poly(acrylamide-co-diacetoneacrylamide).

[0140] Examples of the photosensitizer include sodium 4,4'-diazido-2,2'-stilbenedisulfonate, disodium 4,4'-diazonio-2,2'-dibenzalacetone disulfonate, disodium 2,5-bis(4-azido-2-sulfobenzylidene)cyclopentanone, or at least one selected from the group consisting of sodium 4,4'-diazido-2,2'-stilbenedisulfonate (4,4'-diazido-2,2'-dicinnamylideneacetone sulfonate salt, DACA).

[0141] The solvent can be selected from at least one or more of the group consisting of ethyl acetate, butyl acetate, diethylene glycol dimethyl ether, diethylene glycol dimethyl ethyl ether, dipropylene glycol dimethyl ether, methyl methoxypropionate, ethyl ethoxypropionate (EEP), ethyl lactate, propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether, propylene glycol propyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol methyl acetate, diethylene glycol ethyl acetate, acetone, methyl isobutyl ketone, cyclohexanone, dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, diethyl ether, ethylene glycol dimethyl ether, diglyme, tetrahydrofuran (THF), methanol, ethanol, propanol, isopropanol, methyl cellosolve, ethyl cellosolve, diethylene glycol methyl ether, diethylene glycol ethyl ether, dipropylene glycol methyl ether, toluene, xylene, hexane, heptane, and octane.

[0142] The content of the solid component excluding the solvent in the photoresist resin composition may be about 3 wt% to about 20 wt% based on the total weight. The content of the solid component excluding the solvent in the photoresist resin composition may be about 3 wt% to about 15 wt% based on the total weight. The content of the solid component excluding the solvent in the photoresist resin composition may be about 5 wt% to about 10 wt% based on the total weight.

[0143] The photoresist resin composition may contain the binder resin in a content of about 2 wt% to about 50 wt% based on the total weight. The photoresist resin composition may contain the binder resin in a content of about 3 wt% to about 15 wt%.

[0144] The photo resist composition may contain the photosensitizer at a content of about 0.5 wt% to about 40 wt%. The photo resist composition may contain the photosensitizer at a content of about 0.5 wt% to about 20 wt%. The photo resist composition may contain the photosensitizer at a content of about 0.5 wt% to about 10 wt%. The photo resist composition may contain the photosensitizer at a content of about 0.5 wt% to about 5 wt%.

[0145] The viscosity of the photo resist composition may be about 0.5 cPs to about 10 cPs. The viscosity of the photo resist composition may be about 1 cPs to about 5 cPs. The viscosity of the photo resist composition may be about 0.5 cPs to about 5 cPs.

[0146] The photo resist resin composition may further contain additives such as a leveling agent or an adhesion auxiliary agent.

[0147] The optical substrate 10 may be disposed in the chamber 100. The optical substrate 10 may be temporarily fixed to the chuck 200. The optical substrate 10 may be disposed in the accommodating portion. The optical substrate 10 can be seated on the chuck 200.

[0148] The photo resist layer 50 is formed on the optical substrate 10 using the coating device.

[0149] In order for the photo resist layer 50 to be formed, the interior of the chamber 100 is isolated from the outside by the cover of the chamber 100. Then, with the chuck 200 rotating at high speed, the photo resist resin composition is dropped and coated on the upper surface of the optical substrate 10 by the supply unit 500 of the photo resist resin composition. Thereby, a photo resist resin composition layer may be formed on the optical substrate 10.

[0150] At this time, the chuck 200 can rotate the optical substrate 10 by the following method.

[0151] First, the optical substrate 10 can go through a first rotation stage. The first rotation stage can be carried out at a temperature of about 20°C to about 30°C. The first rotation stage can be carried out at a temperature of about 20°C to about 27°C.

[0152] The first rotation stage may have a first rotation speed. The first rotation speed may be about 30 rpm to about 70 rpm or about 40 rpm to about 60 rpm. The first rotation stage can be carried out for about 1 second to about 5 seconds or about 2 seconds to about 4 seconds.

[0153] Also, in the first rotation stage, the photoresist resin composition can be dropped onto the optical substrate 10. The dropping speed of the photoresist composition may be about 0.5 ml / second to about 5 ml / second or about 1 ml / second to about 4 ml / second.

[0154] After the first rotation stage, the optical substrate 10 can go through a second rotation stage. The second rotation stage can be carried out at a temperature of about 20°C to about 30°C. The second rotation stage may have a second rotation speed. The second rotation speed may be about 50 rpm to about 100 rpm or about 60 rpm to about 90 rpm. The second rotation speed may be even greater than the speed of the first rotation stage. The second rotation speed may be about 5 rpm to about 70 rpm, about 10 rpm to about 70 rpm, or about 20 rpm to about 70 rpm greater than the first rotation speed. The second rotation stage can be carried out for about 3 seconds to about 10 seconds.

[0155] After the second rotation stage, the optical substrate 10 can undergo a third rotation stage. The third rotation stage can be carried out at a temperature of about 20°C to about 30°C. The third rotation stage may have a third rotation speed. The third rotation speed may be about 100 rpm to about 150 rpm, about 110 rpm to about 140 rpm, or about 110 rpm to about 130 rpm. The third rotation speed may be even greater than the speed of the second rotation stage. The third rotation speed may be about 5 rpm to about 70 rpm, about 10 rpm to about 70 rpm, or about 20 rpm to about 70 rpm greater than the second rotation speed. The third rotation stage can be carried out for about 5 seconds to about 13 seconds or about 6 seconds to about 12 seconds.

[0156] After the third rotation stage, the optical substrate 10 can undergo a fourth rotation stage. The fourth rotation stage can be carried out at a temperature of about 20°C to about 30°C. The fourth rotation stage may have a fourth rotation speed. The fourth rotation speed may be about 800 rpm to about 3000 rpm. The fourth rotation speed may be about 800 rpm to about 1500 rpm. The fourth rotation speed may be about 1500 rpm to about 2500 rpm. The fourth rotation speed may be about 2000 rpm to about 3000 rpm. The fourth rotation speed may be even higher than the third rotation speed. The fourth rotation speed may be about 700 rpm to about 2800 rpm higher than the third rotation speed. The speed of the fourth rotation stage may be about 500 rpm to about 2500 rpm higher than the speed of the third rotation stage. The fourth rotation stage can be carried out for about 0.5 seconds to about 2 seconds.

[0157] After the fourth rotation step, the optical substrate 10 can be rotated for the fifth time. The fifth rotation step can be performed at a temperature of about 20°C to about 30°C. The fifth rotation speed may be about 500 rpm to about 2500 rpm. The fifth rotation speed may be about 500 rpm to about 1200 rpm. The fifth step speed may be about 1000 rpm to about 2000 rpm. The fifth rotation speed may be about 1500 rpm to about 2500 rpm. The fifth rotation speed may be even lower than the fourth rotation speed. The fifth rotation speed may be about 300 rpm to about 1500 rpm lower than the fourth rotation speed. The fifth rotation step can be performed for about 1 second to about 5 seconds.

[0158] After the fifth rotation step, the optical substrate 10 can go through a sixth rotation step. The sixth rotation step can be performed at a temperature of about 20°C to about 30°C. The sixth rotation step may have a sixth rotation speed. The sixth rotation speed may be about 100 rpm to about 500 rpm. The sixth rotation speed may be about 100 rpm to about 400 rpm. The sixth rotation speed may be about 100 rpm to about 300 rpm. The sixth rotation speed may be about 200 rpm to about 400 rpm. The sixth rotation speed may be lower than the fifth rotation speed. The sixth rotation speed may be about 200 rpm to about 2300 rpm lower than the fifth rotation speed. The sixth rotation time may be about 30 seconds to about 60 seconds.

[0159] In the sixth rotation step, the photoresist resin composition layer formed on the optical substrate 10 can be dried to remove the solvent.

[0160] As a result, as shown in FIG. 5, the photoresist layer 50 may be formed on the optical substrate 10. Thus, a blank mask including the optical substrate 10 and the photoresist layer 50 can be manufactured.

[0161] As shown in FIG. 6, the photoresist layer 50 may include a flat portion 51 and optical irregularities 52 and 53.

[0162] The flat portion 51 may have a uniform thickness as a whole. Also, the flat portion 51 may have a thickness deviation of less than about 100 Å as a whole. The flat portion 51 may have a thickness deviation of less than about 90 Å as a whole. The flat portion 51 may have a thickness deviation of less than about 80 Å as a whole. The flat portion 51 may have a thickness deviation of less than about 50 Å as a whole. The thickness deviation may be the difference between the maximum thickness and the minimum thickness in the flat portion 51.

[0163] The thickness of the flat portion 51 can be measured by an ellipsometer. The thickness of the flat portion 51 can be measured by, for example, the SE MG series, SE MF series, SE MH series, or SE MI series of Nano-View.

[0164] The thickness of the flat portion 51 may be about 1000 Å to about 10000 Å. The thickness of the flat portion 51 may be about 1000 Å to about 5000 Å. The thickness of the flat portion 51 may be about 1000 Å to about 4000 Å.

[0165] The optical irregularities 52 and 53 may have an optical thickness different from that of the flat portion 51. The optical thickness of the flat portion 51 can be derived by multiplying the refractive index of the flat portion 51 by twice the thickness of the flat portion 51. Also, the optical thickness of the optical irregularities 52 and 53 can be derived by multiplying the refractive index of the optical irregularities 52 and 53 by twice the thickness of the optical irregularities 52 and 53.

[0166] The difference between the optical thickness of the flat portion 51 and the optical thickness of the optical irregularities 52, 53 can exceed about 5 nm. The difference between the optical thickness of the flat portion 51 and the optical thickness of the optical irregularities 52, 53 can exceed about 10 nm. The difference between the optical thickness of the flat portion 51 and the optical thickness of the optical irregularities 52, 53 can exceed about 15 nm. The difference between the optical thickness of the flat portion 51 and the optical thickness of the optical irregularities 52, 53 can exceed about 20 nm. The difference between the optical thickness of the flat portion 51 and the optical thickness of the optical irregularities 52, 53 can exceed about 30 nm. The difference between the optical thickness of the flat portion 51 and the optical thickness of the optical irregularities 52, 53 can exceed about 40 nm. The difference between the optical thickness of the flat portion 51 and the optical thickness of the optical irregularities 52, 53 can exceed about 50 nm.

[0167] The maximum value of the difference between the optical thickness of the flat portion 51 and the optical thickness of the optical irregularities 52, 53 may be about 500 nm.

[0168] The diameter of the optical irregularities 52, 53 can exceed about 10 nm. The diameter of the optical irregularities 52, 53 can exceed about 20 nm. The diameter of the optical irregularities 52, 53 can exceed about 30 nm. The diameter of the optical irregularities 52, 53 can exceed about 40 nm. The diameter of the optical irregularities 52, 53 can exceed about 50 nm. The diameter of the optical irregularities 52, 53 can exceed about 70 nm. The diameter of the optical irregularities 52, 53 can exceed about 100 nm.

[0169] The maximum value of the diameter of the optical irregularities 52, 53 may be about 500 nm.

[0170] Also, the optical irregularities 52, 53 may include a light path changing portion. The light path changing portion can change the path of incident light. Due to the light path changing portion, the path of the light incident on the optical irregularities 52, 53 is distorted, and the incident angle of the light and the reflection angle at the optical irregularities 52, 53 can change with each other.

[0171] That is, for the light incident at the same angle, the reflection angles of the flat portion 51 and the optical unevenness 52 and 53 may be different from each other.

[0172] The optical unevenness 52 and 53 may include a curved surface. The light path changing portion may include the curved surfaces of the optical unevenness 52 and 53.

[0173] As shown in FIG. 8, the optical unevenness 52 and 53 may include a first optical unevenness 52. The first optical unevenness 52 may be disposed within the photoresist layer 50. The first optical unevenness 52 may be disposed in a form immersed in the photoresist layer 50.

[0174] The first optical unevenness 52 may have a refractive index different from that of the flat portion 51. The difference between the refractive indices of the first optical unevenness 52 and 53 and the refractive index of the flat portion 51 may be about 0.05 to about 0.7, 0.03 to about 0.5, 0.01 to about 0.3, 0.1 to about 0.9, or about 0.1 to about 0.8. Thereby, the light path can be changed at the interface between the first optical unevenness 52 and the flat portion 51. That is, the reflection angle can be changed at the interface between the first optical unevenness 52 and the flat portion 51.

[0175] That is, the light path changing portion may include the interface between the first optical unevenness 52 and the flat portion 51. That is, the light path changing portion may include the curved surface of the first optical unevenness 52.

[0176] Further, the second optical unevenness 53 may protrude from the upper surface of the photoresist layer 50. That is, unevenness may be generated in the photoresist layer 50 by the second optical unevenness 53. That is, the height of the upper surface of the second optical unevenness 53 may be even higher than the height of the upper surface of the flat portion 51. The difference between the height of the upper surface of the second optical unevenness 53 and the height of the upper surface of the flat portion 51 may be about 1 nm to about 100 nm.

[0177] Further, a portion of the second optical unevenness 53 that protrudes from the upper surface of the photoresist layer 50 may have a curved surface. That is, the upper surface of the second optical unevenness 53 may protrude from the photoresist layer 50 and be a curved surface.

[0178] The optical path changing portion may include the curved surface of the second optical unevenness 53. The optical path changing portion may include the exposed upper surface of the second optical unevenness 53.

[0179] The optical unevennesses 52 and 53 can be detected by light of about 532 nm. The optical unevennesses 52 and 53 can be detected by a laser of about 532 nm. The optical unevennesses 52 and 53 can be detected by analyzing the light reflected from the photoresist layer 50 when the laser irradiates the photoresist layer 50.

[0180] After the laser irradiates the photoresist layer 50, the reflected light can be sensed via an image sensor. The light reflected from the photoresist layer 50 can be sensed by the image sensor via a confocal and a spatial filter. Then, the signal sensed via the image sensor can be processed into an 8-bit 256-tone gray-scale image. The image can be processed at 640×480 pixels.

[0181] Also, when a difference exceeding about 3 tones occurs in the pixels of the image, the optical unevennesses 52 and 53 can be detected. When a difference exceeding about 5 tones occurs in the pixels of the image, the optical unevennesses 52 and 53 can be detected. When a difference exceeding about 7 tones occurs in the pixels of the image, the optical unevennesses 52 and 53 can be detected. When a difference exceeding about 10 tones occurs in the pixels of the image, the optical unevennesses 52 and 53 can be detected.

[0182] In addition, the average area of the optical unevenness 52, 53 can be calculated based on the number of pixels detected in the optical unevenness 52, 53 in the image.

[0183] The optical unevenness 52, 53 can be detected by an optical surface inspection device. The optical unevenness 52, 53 can be detected by M6640S or M6641S of LASERTEC.

[0184] The number of the optical unevenness 52, 53 in the photoresist layer 50 may be less than about 50 pieces / 36 inches. 2 The number of the optical unevenness 52, 53 in the photoresist layer 50 may be less than about 40 pieces / 36 inches. 2 The number of the optical unevenness 52, 53 in the photoresist layer 50 may be less than about 30 pieces / 36 inches. 2 The number of the optical unevenness 52, 53 in the photoresist layer 50 may be less than about 20 pieces / 36 inches. 2 The number of the optical unevenness 52, 53 in the photoresist layer 50 may be less than about 10 pieces / 36 inches. 2 The number of the optical unevenness 52, 53 in the photoresist layer 50 may be less than about 1 piece / 36 inches.

[0185] The number of the optical unevenness 52, 53 in the photoresist layer 50 may be from about 1 piece / 36 inches to less than about 50 pieces / 36 inches. 2 ~ about 50 pieces / 36 inches 2 The number of the optical unevenness 52, 53 in the photoresist layer 50 may be from about 1 piece / 36 inches to less than about 40 pieces / 36 inches. 2 ~ about 40 pieces / 36 inches 2 The number of the optical unevenness 52, 53 in the photoresist layer 50 may be from about 1 piece / 36 inches to less than about 30 pieces / 36 inches. 2 ~ about 30 pieces / 36 inches 2 The number of the optical unevenness 52, 53 in the photoresist layer 50 may be from about 1 piece / 36 inches to less than about 20 pieces / 36 inches. 2 ~ about 20 pieces / 36 inches 2It may be less than. The number of the optical unevennesses 52 and 53 in the photoresist layer 50 is about 1 piece / 36 inches 2 ~ about 10 pieces / 36 inches 2 It may be less than.

[0186] Since the photoresist layer 50 includes the optical unevennesses 52 and 53 in the above-described number, the photoresist layer 50 can be developed precisely. That is, since the photoresist layer 50 includes the optical unevennesses 52 and 53 in the above-described number, the precision in the exposure process of the photoresist layer 50 can be improved. Thereby, the method for manufacturing a blank mask according to the embodiment can provide a precise photomask.

[0187] As shown in FIG. 7, the photoresist layer 50 may include 49 regions.

[0188] The 49 regions can be set by seven virtual straight lines arranged horizontally at regular intervals and seven virtual straight lines arranged vertically at regular intervals. That is, the 49 regions may be formed by dividing the photoresist layer 50 into seven parts at regular intervals in the horizontal direction and seven parts at regular intervals in the vertical direction in a plan view. That is, the 49 regions have a square shape, have the same size, and can divide the photoresist. For example, the 49 regions may be squares having a horizontal length and a vertical length of 6 / 7 inches.

[0189] Further, the 49 regions may include a first region (1-1), a second region (2-1, 2-2... 2-8), a third region (3-1, 3-2... 3-16), and a fourth region (4-1, 4-2... 4-24).

[0190] The first region (1-1) may be located at the central portion in the photoresist layer 50. More specifically, the first region (1-1) may be located in the middle of the photoresist layer 50.

[0191] The second region (2-1, 2-2...2-8) may be arranged around the first region (1-1). The second region (2-1, 2-2...2-8) may surround the first region (1-1). The second region (2-1, 2-2...2-8) may be directly adjacent to the first region (1-1).

[0192] The third region (3-1, 3-2...3-16) may be arranged around the second region (2-1, 2-2...2-8). The third region (3-1, 3-2...3-16) may surround the second region (2-1, 2-2...2-8). The third region (3-1, 3-2...3-16) may be directly adjacent to the second region (2-1, 2-2...2-8).

[0193] The fourth region (4-1, 4-2...4-24) may be arranged around the third region (3-1, 3-2...3-16). The fourth region (4-1, 4-2...4-24) may surround the third region (3-1, 3-2...3-16). The fourth region (4-1, 4-2...4-24) may be directly adjacent to the third region (3-1, 3-2...3-16). The fourth region (4-1, 4-2...4-24) may be located at the outermost contour of the photoresist layer 50.

[0194] In the 49 regions, the thickness deviation of the photoresist layer 50 may be less than about 100 Å. The thickness deviation may be the difference between the maximum thickness and the minimum thickness among the 49 regions. In the 49 regions, the thickness deviation of the photoresist layer 50 may be less than about 90 Å. In the 49 regions, the thickness deviation of the photoresist layer 50 may be less than about 80 Å. In the 49 regions, the thickness deviation of the photoresist layer 50 may be less than about 70 Å. In the 49 regions, the thickness deviation of the photoresist layer 50 may be less than about 60 Å. In the 49 regions, the thickness deviation of the photoresist layer 50 may be less than about 50 Å.

[0195] In the 49 regions, the minimum value of the thickness deviation of the photoresist layer 50 may be about 3 Å.

[0196] In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2...4-24) may be even greater than the average thickness of the third region (3-1, 3-2...3-16). In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2...4-24) may be greater than the average thickness of the third region (3-1, 3-2...3-16) by about 3 Å to about 10 Å. In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2...4-24) may be greater than the average thickness of the third region (3-1, 3-2...3-16) by about 4 Å to about 10 Å. In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2...4-24) may be greater than the average thickness of the third region (3-1, 3-2...3-16) by about 5 Å to about 10 Å.

[0197] In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2... 4-24) may be even greater than the average thickness of the second region (2-1, 2-2... 2-8). In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2... 4-24) may be greater by about 3 Å to about 10 Å than the average thickness of the second region (2-1, 2-2... 2-8). In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2... 4-24) may be greater by about 4 Å to about 10 Å than the average thickness of the second region (2-1, 2-2... 2-8). In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2... 4-24) may be greater by about 5 Å to about 10 Å than the average thickness of the second region (2-1, 2-2... 2-8).

[0198] In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2... 4-24) may be even greater than the average thickness of the first region (1-1). In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2... 4-24) may be greater by about 3 Å to about 10 Å than the average thickness of the first region (1-1). In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2... 4-24) may be greater by about 4 Å to about 10 Å than the average thickness of the first region (1-1). In the photoresist layer 50, the average thickness of the fourth region (4-1, 4-2... 4-24) may be greater by about 5 Å to about 10 Å than the average thickness of the first region (1-1).

[0199] In the photoresist layer 50, the average thickness of the first region (1-1) may be even greater than the average thickness of the second regions (2-1, 2-2...2-8). In the photoresist layer 50, the average thickness of the first region (1-1) may be about 3 Å to about 10 Å greater than the average thickness of the second regions (2-1, 2-2...2-8). In the photoresist layer 50, the average thickness of the first region (1-1) may be about 4 Å to about 10 Å greater than the average thickness of the second regions (2-1, 2-2...2-8). In the photoresist layer 50, the average thickness of the first region (1-1) may be about 5 Å to about 10 Å greater than the average thickness of the second regions (2-1, 2-2...2-8).

[0200] In the photoresist layer 50, the average thickness of the first region (1-1) may be even greater than the average thickness of the third regions (3-1, 3-2...3-16). In the photoresist layer 50, the average thickness of the first region (1-1) may be about 3 Å to about 10 Å greater than the average thickness of the third regions (3-1, 3-2...3-16). In the photoresist layer 50, the average thickness of the first region (1-1) may be about 4 Å to about 10 Å greater than the average thickness of the third regions (3-1, 3-2...3-16). In the photoresist layer 50, the average thickness of the first region (1-1) may be about 5 Å to about 10 Å greater than the average thickness of the third regions (3-1, 3-2...3-16).

[0201] The density of the optical unevenness in the fourth regions (4-1, 4-2...4-24) may be even greater than the density of the optical unevenness in the first region (1-1), the second regions (2-1, 2-2...2-8), and the third regions (3-1, 3-2...3-16). The density of the optical unevenness is a value obtained by dividing the number of the optical unevenness by the area of the region where the optical unevenness is arranged.

[0202] That is, the density of the optical unevenness in the fourth region (4-1, 4-2... 4-24) may be a value obtained by dividing the total number of the optical unevenness arranged in the fourth region (4-1, 4-2... 4-24) by the total area of the fourth region (4-1, 4-2... 4-24).

[0203] Also, the density of the optical unevenness in the first region (1-1), the second region (2-1, 2-2... 2-8), and the third region (3-1, 3-2... 3-16) is a value obtained by dividing the total number of the optical unevenness arranged in the first region (1-1), the second region (2-1, 2-2... 2-8), and the third region (3-1, 3-2... 3-16) by the total area of the first region (1-1), the second region (2-1, 2-2... 2-8), and the third region (3-1, 3-2... 3-16).

[0204] The density of the optical unevenness in the fourth region (4-1, 4-2... 4-24) is about 15 pieces / 36 inch 2 ~25 pieces / 36 inch 2 and may be. The density of the optical unevenness in the fourth region (4-1, 4-2... 4-24) is about 10 pieces / 36 inch 2 ~30 pieces / 36 inch 2 and may be. The density of the optical unevenness in the fourth region (4-1, 4-2... 4-24) is about 17 pieces / 36 inch 2 ~22 pieces / 36 inch 2 and may be.

[0205] The density of the optical unevenness in the first region (1-1), the second region (2-1, 2-2... 2-8), and the third region (3-1, 3-2... 3-16) is about 5 pieces / 36 inch 2 ~20 pieces / 36 inch 2 and may be. The density of the optical unevenness in the first region (1-1), the second region (2-1, 2-2... 2-8), and the third region (3-1, 3-2... 3-16) is about 3 pieces / 36 inch 2 ~25 pieces / 36 inch 2It may also be. The density of the optical irregularities in the first region (1-1), the second regions (2-1, 2-2...2-8), and the third regions (3-1, 3-2...3-16) is about 7 pieces / 36 inches 2 ~15 pieces / 36 inches 2 It may also be.

[0206] The difference between the density of the optical irregularities in the fourth region (4-1, 4-2...4-24) and the density of the optical irregularities in the first region (1-1), the second regions (2-1, 2-2...2-8), and the third regions (3-1, 3-2...3-16) is about 1 piece / 36 inches 2 ~20 pieces / 36 inches 2 It may also be. The difference between the density of the optical irregularities in the fourth region (4-1, 4-2...4-24) and the density of the optical irregularities in the first region (1-1), the second regions (2-1, 2-2...2-8), and the third regions (3-1, 3-2...3-16) is about 1 piece / 36 inches 2 ~15 pieces / 36 inches 2 It may also be. The difference between the density of the optical irregularities in the fourth region (4-1, 4-2...4-24) and the density of the optical irregularities in the first region (1-1), the second regions (2-1, 2-2...2-8), and the third regions (3-1, 3-2...3-16) is about 3 pieces / 36 inches 2 ~15 pieces / 36 inches 2 It may also be. The difference between the density of the optical irregularities in the fourth region (4-1, 4-2...4-24) and the density of the optical irregularities in the first region (1-1), the second regions (2-1, 2-2...2-8), and the third regions (3-1, 3-2...3-16) is about 5 pieces / 36 inches 2 ~10 pieces / 36 inches 2 It may also be.

[0207] Also, the number of the optical irregularities in each fourth region may be 3 or less. The number of the optical irregularities in each fourth region may be 2 or less.

[0208] Also, the number of the optical unevennesses in each of the third regions may be three or less. The number of the optical unevennesses in each of the third regions may be two or less.

[0209] Also, the number of the optical unevennesses in each of the second regions may be three or less. The number of the optical unevennesses in each of the second regions may be two or less.

[0210] Also, the number of the optical unevennesses in the first region (1-1) may be three or less. The number of the optical unevennesses in the first region (1-1) may be two or less.

[0211] Also, the total number of the optical unevennesses in the fourth region (4-1, 4-2...4-24) may be about 1 to about 20. The total number of the optical unevennesses in the fourth region (4-1, 4-2...4-24) may be about 3 to about 15.

[0212] Also, the total number of the optical unevennesses in the first region (1-1), the second regions (2-1, 2-2...2-8) and the third regions (3-1, 3-2...3-16) may be 0 to about 15. The total number of the optical unevennesses in the first region (1-1), the second regions (2-1, 2-2...2-8) and the third regions (3-1, 3-2...3-16) may be 1 to about 10. The total number of the optical unevennesses in the first region (1-1), the second regions (2-1, 2-2...2-8) and the third regions (3-1, 3-2...3-16) may be 2 to about 7.

[0213] The photoresist layer 50 may be selectively irradiated with light, and the light-shielding film may be selectively etched to form a light-shielding pattern film 35. Thereby, as shown in FIG. 9, a photomask 2 including the light-transmissive substrate 20 and the light-shielding pattern film 35 disposed on the light-transmissive substrate 20 may be formed.

[0214] The light-shielding pattern film 35 contains at least one of a transition metal, oxygen, and nitrogen.

[0215] The light-shielding pattern film 35 may be formed by patterning the light-shielding film 30 of the blank mask 100 described above.

[0216] The description of the physical properties, composition, structure, etc. of the light-shielding pattern film 35 is omitted because it overlaps with the description of the light-shielding film 30 of the blank mask 1.

[0217] The method for manufacturing a semiconductor device according to the embodiment includes a preparation step of arranging a light source, a photomask 2, and a semiconductor wafer coated with a resist film, an exposure step of selectively transmitting and emitting light incident from the light source through the photomask 2 onto the semiconductor wafer, and a development step of developing a pattern on the semiconductor wafer.

[0218] The photomask 2 includes a light-transmissive substrate 20 and a light-shielding pattern film 35 disposed on the light-transmissive substrate 20.

[0219] The light-shielding pattern film 35 contains at least one of a transition metal, oxygen, nitrogen, and carbon.

[0220] In the preparation step, the light source is a device capable of generating exposure light with a short wavelength. The exposure light may be light with a wavelength of 200 nm or less. The exposure light may be ArF light with a wavelength of 193 nm.

[0221] A lens may be further disposed between the photomask 2 and the semiconductor wafer. The lens has a function of reducing the shape of the circuit pattern on the photomask 2 and transferring it onto the semiconductor wafer. The lens is not limited as long as it can be generally applied to the exposure process of an ArF semiconductor wafer. By way of example, a lens made of calcium fluoride (CaF2) can be applied as the lens.

[0222] In the exposure step, exposure light can be selectively transmitted onto the semiconductor wafer through the photomask 2. In such a case, chemical modification may occur in the portion of the resist film where the exposure light is incident.

[0223] In the development step, the semiconductor wafer after the exposure step can be treated with a developing solution to develop a pattern on the semiconductor wafer. When the applied resist film is a positive resist, the portion of the resist film where the exposure light is incident can be dissolved by the developing solution. When the applied resist film is a negative resist, the portion of the resist film where the exposure light is not incident can be dissolved by the developing solution. The resist film is formed into a resist pattern by the developing solution treatment. A pattern can be formed on the semiconductor wafer using the resist pattern as a mask.

[0224] The description of the photomask 2 is omitted because it overlaps with the above content.

[0225] The method for manufacturing a blank mask according to the embodiment includes a step of maintaining the inside of the nozzle 520 for ejecting the photoresist composition filled with the photoresist composition. The method for manufacturing a blank mask according to the embodiment also includes a step of removing the photoresist composition inside the nozzle 520. Thereby, the residue adhering to the inside of the nozzle 520 can be easily removed.

[0226] Thereby, the method for manufacturing a blank mask according to the embodiment can prevent the residue 513 from flowing into the photoresist layer 50.

[0227] Thereby, the blank mask according to the embodiment can reduce the number of optical irregularities 52, 53 that may be caused by the residue or the like. The blank mask according to the embodiment may include the optical irregularities 52, 53 less than 30 pieces / 36 inches. 2 and may include the optical irregularities 52, 53.

[0228] Accordingly, the method for manufacturing a blank mask according to the embodiment can implement a photoresist layer 50 having optical flatness as a whole. Accordingly, the photoresist layer 50 can precisely pattern the light-shielding film.

[0229] The blank mask according to the embodiment may include a photoresist layer 50 having a high thickness uniformity as a whole. Accordingly, the photoresist layer 50 can be precisely patterned in the exposure and development processes. Accordingly, the blank mask according to the embodiment can precisely pattern the light-shielding film and provide a precise photomask.

[0230] In particular, in the blank mask according to the embodiment, the photoresist layer 50 may have a relatively thicker outer peripheral region. That is, the process conditions are adjusted so that the outer peripheral region of the photoresist layer 50 is formed to be relatively slightly thicker, and the photoresist layer 50 may have a uniform thickness as a whole.

[0231] Also, the process for forming the photoresist layer 50 may include first to sixth rotation stages. Accordingly, the photoresist layer 50 may have a uniform thickness as a whole. Also, since the photoresist layer 50 is formed by the above-described process, it may have a relatively slightly thicker outer peripheral region.

[0232] Also, the photoresist layer 50 may include optical irregularities. In particular, the photoresist layer 50 may be formed such that the optical density of the outer peripheral region is even higher. Accordingly, the photoresist layer 50 can reduce the number of optical irregularities as a whole.

[0233] In particular, the blank mask according to the embodiment may include the optical irregularities at less than 30 pieces / 36 inches 2

[0234] ​ Accordingly, the method for manufacturing a blank mask according to the embodiment can embody a photoresist layer 50 having optical flatness as a whole. Accordingly, the photoresist layer 50 can precisely pattern the light-shielding film.

[0235] In particular, as described above, since the photoresist layer 50 has the optical unevenness detected by the laser of 532 nm in the above number, it can be precisely developed by ultraviolet rays.

[0236] Accordingly, the blank mask according to the embodiment can provide a photomask having a precise pattern.

[0237] Accordingly, the blank mask according to the embodiment can reduce the number of optical unevenness 52, 53 that can be caused by the residue 513 or the like. The blank mask according to the embodiment may include the optical unevenness 52, 53 of less than 30 pieces / 36 inches 2 and may include the optical unevenness 52, 53.

[0238] Accordingly, the method for manufacturing a blank mask according to the embodiment can embody a photoresist layer 50 having optical flatness as a whole. Accordingly, the photoresist layer 50 can precisely pattern the light-shielding film.

[0239] Accordingly, the blank mask according to the embodiment can provide a photomask having a precise pattern.

[0240] The apparatus and method for manufacturing a blank mask according to the embodiment can provide a blank mask having improved performance.

[0241] As described above, the preferred embodiments of the present invention have been described in detail. However, the scope of the rights of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims also belong to the scope of the rights of the present invention.

[0242] Production Example Photoresist Composition #1 An FEP171 solution (FUJIFILM Arch Co, Ltd) was used, and PGMEA (propylene glycol monomethyl ether acetate) and PGME (propylene glycol monomethyl ether) were used at a ratio of 8 to 2 as solvents. Also, the solid content of the FEP171 solution was approximately 8.5 wt%. The viscosity of the FEP171 solution was approximately 3 cP.

[0243] Photoresist Composition #2 An XFP255 solution (FUJIFILM Arch Co, Ltd) was used, and PGMEA (propylene glycol monomethyl ether acetate) and PGME (propylene glycol monomethyl ether) were used at a ratio of 8 to 2 as solvents. Also, the solid content of the XFP255 solution was approximately 6.5 wt%. The viscosity of the XFP255 solution was approximately 1.5 cP.

[0244] Example 1 A quartz substrate having a size of approximately 6 inches × approximately 6 inches was used, and the quartz substrate had a thickness of 0.25 inches. An MoSi film with a thickness of approximately (600 - 1000 Å) and a Cr film with a thickness of approximately (500 - 900 Å) were formed on the quartz substrate by a sputtering process. Then, the quartz substrate on which the MoSi and Cr films were formed was fixed to a chuck.

[0245] After the FEP171 solution was dropped from a nozzle with a height of about 0.5 cm onto the quartz substrate, the quartz substrate was rotated at a temperature of about 23 degrees and a speed of about 50 rpm for about 3 seconds (first stage). Thereafter, the quartz substrate was rotated at a temperature of about 23 degrees and a speed of about 80 rpm for 5 seconds (second stage), rotated at a temperature of about 23 degrees and a speed of about 100 rpm for over 8 seconds (third stage), rotated at a temperature of about 23 degrees and a speed of about 2200 rpm for over 1 second (fourth stage), and rotated at a temperature of about 23 degrees and a speed of about 1750 rpm for 3 seconds (fifth stage).

[0246] Thereafter, the quartz substrate was rotated at a temperature of about 23 degrees and a speed of about 300 rpm for over 40 seconds (sixth stage).

[0247] Thereby, an optical substrate with a photoresist layer formed thereon was manufactured.

[0248] Examples 2 to 5 and Comparative Examples As shown in Tables 1 and 2 below, the nozzle height, resist composition, and coating conditions were adjusted. Other processes refer to Example 1.

[0249] [Table 1] JPEG2025105593000003.jpg11

[0250] [Table 2] JPEG2025105593000005.jpg11

[0251] Evaluation Examples 1. Thickness of the resist layer The resist layer was divided into 49 regions at equal intervals in 7 parts each in the horizontal and vertical directions. The thickness was measured for each region in the resist layer. In order to measure the thickness, it is measured with a spectroscopic ellipsometer (manufacturer: Nano-View CO., LTD, brand: MG-PRO).

[0252] 2. Number of optical irregularities In the optical substrates manufactured in the examples and comparative examples, in each region of the resist layer, the number of optical irregularities has been measured by an optical surface inspection equipment (M6641S manufactured by LASERTEC). The optical irregularities have a diameter of 0.01 μm to 10 μm.

[0253] As shown in Table 3 below, the thickness of the resist layer manufactured in Example 1 has been measured in 49 regions. In Table 3, FIG. 8 is referred to, and each region is divided into columns and rows, and the unit was Å.

[0254]

Table 3

[0255] As shown in Table 4 below, the thickness of the resist layer manufactured in Example 2 has been measured in 49 regions. In Table 4, FIG. 8 is referred to, and each region is divided into columns and rows, and the unit was Å.

[0256]

Table 4

[0257] As shown in Table 5 below, the thickness of the resist layer manufactured in Example 3 has been measured in 49 regions. In Table 5, FIG. 8 is referred to, and each region is divided into columns and rows, and the unit was Å.

[0258]

Table 5

[0259] As shown in Table 6 below, the thickness of the resist layer manufactured in Example 4 has been measured in 49 regions. In Table 6, FIG. 8 is referred to, and each region is divided into columns and rows, and the unit was Å.

[0260]

Table 6

[0261] As shown in Table 7 below, the thickness of the resist layer produced in Example 5 was measured in 49 regions. In Table 7, FIG. 8 is referred to, and each region was divided into columns and rows, and the unit was Å.

[0262]

Table 7

[0263] As shown in Table 8 below, the thickness of the resist layer produced in Comparative Example 1 was measured in 49 regions. In Table 8, FIG. 8 is referred to, and each region was divided into columns and rows, and the unit was Å.

[0264]

Table 8

[0265] As shown in Table 9 below, the thickness of the resist layer produced in Comparative Example 2 was measured in 49 regions. In Table 9, FIG. 8 is referred to, and each region was divided into columns and rows, and the unit was Å.

[0266]

Table 9

[0267] As shown in Table 10 below, the thickness of the resist layer produced in Comparative Example 3 was measured in 49 regions. In Table 10, FIG. 8 is referred to, and each region was divided into columns and rows, and the unit was Å.

[0268]

Table 10

[0269] As shown in Table 11 below, the thickness of the resist layer manufactured in Comparative Example 4 was measured in 49 regions. In Table 11, Figure 8 is referred to, and each region was divided into columns and rows, with the unit being Å.

[0270]

Table 11

[0271] As shown in Table 12 below, in the resist layer manufactured in Example 1, the number of optical irregularities was measured in 49 regions. In Table 12, Figure 8 is referred to, and each region was divided into columns and rows.

[0272]

Table 12

[0273] As shown in Table 13 below, in the resist layer manufactured in Example 2, the number of optical irregularities was measured in 49 regions. In Table 13, Figure 8 is referred to, and each region was divided into columns and rows.

[0274]

Table 13

[0275] As shown in Table 14 below, in the resist layer manufactured in Example 3, the number of optical irregularities was measured in 49 regions. In Table 14, Figure 8 is referred to, and each region was divided into columns and rows.

[0276]

Table 14

[0277] As shown in Table 15 below, in the resist layer manufactured in Example 4, the number of optical irregularities was measured in 49 regions. In Table 15, Figure 8 is referred to, and each region was divided into columns and rows.

[0278]

Table 15

[0279] As shown in Table 16 below, in the resist layer manufactured in Example 5, the number of optical irregularities was measured in 49 regions. In Table 16, FIG. 8 is referred to, and each region is divided into columns and rows.

[0280]

Table 16

[0281] As shown in Table 17 below, in the resist layer manufactured in Comparative Example 1, the number of optical irregularities was measured in 49 regions. In Table 17, FIG. 8 is referred to, and each region is divided into columns and rows.

[0282]

Table 17

[0283] As shown in Table 18 below, in the resist layer manufactured in Comparative Example 2, the number of optical irregularities was measured in 49 regions. In Table 18, FIG. 8 is referred to, and each region is divided into columns and rows.

[0284]

Table 18

[0285] As shown in Table 19 below, in the resist layer manufactured in Comparative Example 3, the number of optical irregularities was measured in 49 regions. In Table 19, FIG. 8 is referred to, and each region is divided into columns and rows.

[0286]

Table 19

[0287] As shown in Table 20 below, in the resist layer manufactured in Comparative Example 4, the number of optical irregularities was measured in 49 regions. In Table 20, FIG. 8 is referred to, and each region was divided into columns and rows.

[0288]

Table 20

[0289] As shown in Tables 12 to 20, the photoresist layer according to the examples contains optical irregularities in a small number.

Explanation of Reference Numerals

[0290] 10 Optical substrate 30 Light-shielding film 50 Photoresist layer 51 Flat portion 52, 53 Optical irregularities

Claims

1. An optical substrate including a light-transmissive substrate and a light-shielding film disposed on the light-transmissive substrate, and a photoresist layer disposed on the optical substrate, wherein the photoresist layer includes 49 regions divided into 7 regions at equal intervals in the horizontal direction and 7 regions at equal intervals in the vertical direction, the 49 regions are a first region corresponding to the center of the optical substrate, a second region disposed along the periphery of the first region, a third region disposed along the periphery of the second region, and a fourth region corresponding to the outer contour of the optical substrate, and include the density of the optical irregularities in the fourth region is even greater than the density of the optical irregularities in the first region, the second region, and the third region, a blank mask.

2. The optical unevenness is detected by a laser of 532 nm and arranged on the light-shielding film at less than 30 pieces / 36 inches. ２ ​ The blank mask according to Claim 1.

3. The density of the optical unevenness in the fourth region is 15 pieces / 36 inches ２ to 25 pieces / 36 inches ２ is The blank mask according to Claim 1.

4. The density of the optical irregularities in the first region, the second region, and the third region is 5 pieces / 36 inches ２ to 20 pieces / 36 inches ２ is The blank mask according to Claim 3.

5. The diameter of the optical irregularities is from 10 nm to 500 nm, the blank mask according to Claim 1.

6. The difference between the density of the optical unevenness in the fourth region and the densities of the optical unevenness in the first region, the second region, and the third region is 1 piece / 36 inches ２ to 15 pieces / 36 inches ２ is The blank mask according to Claim 1.

7. The number of the optical irregularities in each fourth region is 3 or less, the blank mask according to Claim 1.

8. The photoresist layer includes a flat portion disposed on the light-shielding portion, the optical irregularities have an optical thickness different from that of the light-shielding portion, the blank mask according to Claim 1.

9. The optical irregularities include a light path changing portion, the blank mask according to Claim 8.

10. The light path changing portion has a refractive index different from that of the flat portion, the blank mask according to Claim 9.

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