Blank mask and method for manufacturing the same

Abstract

To provide a blank mask and a method of fabricating the same, the blank mask being for fabricating a photomask having low defect occurrence, an improved number of uses, and high precision.SOLUTION: A blank mask 100 includes a light-transmissive substrate 10, and a light-shielding film 20 positioned on the light-transmissive substrate. A method of fabricating the blank mask includes: forming a light-shielding film on a light-transmissive substrate; and cleaning the light-shielding film with a cleaning solution, where, in the cleaning step, the light-shielding film has a thickness change of less than 15 nm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The examples relate to blank masks and methods for manufacturing them. [Background technology]

[0002] The increasing integration of semiconductor devices has led to a demand for miniaturization of circuit patterns in these devices. This has further emphasized the importance of lithography technology, which develops circuit patterns on the surface of a wafer using a photomask.

[0003] To develop miniaturized circuit patterns, the exposure light source used in the exposure process needs to have a shorter wavelength. In recent years, exposure light sources such as ArF excimer lasers (wavelength 193 nm) have been used.

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

[0005] A binary mask has a configuration in which a light-shielding layer pattern is formed on a light-transmitting substrate. In a binary mask, on the surface where the pattern is formed, the transparent areas without the light-shielding layer transmit exposure light, while the light-shielding areas with the light-shielding layer block exposure light, thereby exposing the pattern onto the resist film on the surface of the wafer. However, as the pattern becomes finer, problems may arise in developing the fine pattern due to the diffraction of light generated at the edges of the transparent areas during the exposure process.

[0006] Phase shift masks include Levenson type, Outrigger type, and Half-tone type. Of these, the Half-tone type phase shift mask has a configuration in which a pattern formed of a semi-transparent film is formed on a light-transmitting substrate 10. In the Half-tone type phase shift mask, on the surface in which the pattern is formed, the transparent parts that do not contain the semi-transparent layer transmit exposure light, while the semi-transparent parts that contain the semi-transparent layer transmit attenuated exposure light. The attenuated exposure light has a phase difference compared to the exposure light that has passed through the transparent parts. As a result, the diffracted light generated at the edges of the transparent parts is canceled out by the exposure light that has passed through the semi-transparent parts, and the phase shift mask can form an even more sophisticated and fine pattern on the surface of the wafer. [Prior art documents] [Patent Documents]

[0007] The relevant prior literature is as follows: [Patent Document 1] Korean Published Patent No. 10-2012-0057488 [Patent Document 2] Korean Published Patent No. 10-2014-0130420 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The present invention aims to provide a blank mask and a method for manufacturing the same that can provide a photomask with fewer defects, an improved number of uses, and high precision. [Means for solving the problem]

[0009] The method for manufacturing a blank mask according to the example includes the steps of forming a light-shielding film on a light-transmitting substrate and washing the light-shielding film with a cleaning solution, wherein the change in the thickness of the light-shielding film during the washing step may be less than 15 nm.

[0010] In a method for manufacturing a blank mask according to an embodiment, the method further includes a step of forming a phase inversion film on the light transmissive substrate, and the light shielding film may be formed on the phase inversion film.

[0011] In a method for manufacturing a blank mask according to an embodiment, the content of halogen ions on the entire surface of the blank mask is less than 0.1 ng / cm 2 and the content of nitrogen-based ions is less than 3 ng / cm 2 and the content of sulfur-based ions may be less than 0.1 ng / cm 2

[0012] In a method for manufacturing a blank mask according to an embodiment, the halogen ions include chlorine-based ions, the nitrogen-based ions include nitrite ions, nitric acid ions and ammonia, and the sulfur-based ions may include sulfate ions.

[0013] In a method for manufacturing a blank mask according to an embodiment, the cleaning liquid may include carbonated water.

[0014] In a method for manufacturing a blank mask according to an embodiment, the change in the transmittance of the light shielding film in the cleaning step may be less than 0.05%.

[0015] In a method for manufacturing a blank mask according to an embodiment, the change in the optical density of the light shielding film in the cleaning step may be less than 0.07.

[0016] In a method for manufacturing a blank mask according to an embodiment, the change in the reflectance of the light shielding film in the cleaning step may be less than 0.5%.

[0017] In a method for manufacturing a blank mask according to an embodiment, the change in the thickness of the light shielding film in the cleaning step may be 0.3 nm to 3 nm.

[0018] ​In a method for manufacturing a blank mask according to one embodiment, the light-shielding film comprises a first light-shielding layer disposed on the light-transmitting substrate and a second light-shielding layer disposed on the first light-shielding layer, wherein the second light-shielding layer may contain nitrogen in a content of 20 atom% to 40 atom%, chromium in a content of 30 atom% to 50 atom%, and oxygen in a content of 20 atom% to 40 atom%.

[0019] In the method for manufacturing a blank mask according to one embodiment, the first light-shielding layer may contain nitrogen in a content of 10 atom% to 30 atom%, chromium in a content of 60 atom% to 90 atom%, and oxygen in a content of 0.5 atom% to 10 atom%.

[0020] In the method for manufacturing a blank mask according to one embodiment, the second light-shielding layer may contain carbon in an amount of less than 5 atom%.

[0021] The blank mask according to the example comprises a light-transmitting substrate and a light-shielding film disposed on the light-transmitting substrate, and the halogen ion content on the overall surface is 0.05 ng / cm³. 2 The nitrogen ion content is less than 2 ng / cm³. 2 The sulfur ion content is less than 0.1 ng / cm³. 2 It is acceptable to be less than [a certain value].

[0022] In one embodiment of the blank mask, the change in the thickness of the light-shielding film measured by the following measurement method may be less than 15 nm.

[0023] [Measurement method] The light-shielding film is immersed in carbonated water having a carbon dioxide concentration of 2000 mg / l for 10 minutes, and the change in the thickness of the light-shielding film is the difference between the thickness of the light-shielding film before immersion and the thickness after immersion.

[0024] In a blank mask according to an embodiment, the change in transmittance of the light-shielding film is less than 0.05%, the change in optical density of the light-shielding film is less than 0.07, the change in reflectivity of the light-shielding film is less than 0.5%, the change in transmittance is the difference between the transmittance before immersion and the transmittance after immersion in the light-shielding film, the change in optical density is the difference between the optical density before immersion and the optical density after immersion in the light-shielding film, and the change in reflectivity may be the difference between the reflectivity before immersion and the reflectivity after immersion in the light-shielding film.

[0025] In a blank mask according to an embodiment, the light-shielding film includes a first light-shielding layer disposed on the light-transmissive substrate and a second light-shielding layer disposed on the first light-shielding layer, and the second light-shielding layer may contain nitrogen element with a content of 20 atom% to 40 atom%, chromium element with a content of 30 atom% to 50 atom%, and oxygen element with a content of 20 atom% to 40 atom%.

[0026] In a blank mask according to an embodiment, the first light-shielding layer may contain nitrogen element with a content of 10 atom% to 30 atom%, chromium element with a content of 60 atom% to 90 atom%, and oxygen element with a content of 0.5 atom% to 10 atom%.

[0027] In a blank mask according to an embodiment, the change in thickness of the light-shielding film may be 0.3 nm to 3 nm.

[0028] In a blank mask according to an embodiment, the change in thickness of the light-shielding film may be 0.1 nm to 1 nm.

[0029] A photomask according to an embodiment includes a light-transmissive substrate and a light-shielding film disposed on the light-transmissive substrate, and the content of halogen ions on the entire surface is less than 0.05 ng / cm 2 and the content of nitrogen-based ions is less than 2 ng / cm 2 and the content of sulfur-based ions may be less than 0.1 ng / cm. 2

Advantages of the Invention

[0030] The blank mask manufacturing method according to the examples minimizes thickness changes during the washing stage. Furthermore, the blank mask manufacturing method according to the examples can minimize transmittance changes during the washing stage. The blank mask manufacturing method according to the examples can minimize optical density changes during the washing stage. The blank mask manufacturing method according to the examples can minimize reflectance changes during the washing stage.

[0031] Therefore, the blank mask manufacturing method according to the examples may result in a low ion concentration on the surface. The concentrations of halogen ions, nitrogen ions, and sulfur ions on the surface of the blank mask according to the examples may be low.

[0032] In the method for manufacturing a blank mask according to the example, the cleaning solution may contain carbonated water. This allows the method for manufacturing a blank mask according to the example to reduce the concentrations of halogen ions, nitrogen ions, and sulfur-based ions while minimizing the changes in thickness, transmittance, optical density, and reflectance during the cleaning step. [Brief explanation of the drawing]

[0033] [Figure 1] This is a cross-sectional view showing one cross-section of a blank mask according to one embodiment. [Figure 2] This is a cross-sectional view showing one cross-section of a blank mask from another embodiment. [Figure 3] This is a cross-sectional view showing a cross-section of a blank mask from another embodiment. [Figure 4] This is a cross-sectional view showing one cross-section of a photomask according to one embodiment. [Figure 5] This figure shows the process of cleaning the blank mask according to the example. [Modes for carrying out the invention]

[0034] The following descriptions detail embodiments so that they can be easily implemented by a person with ordinary skill in the art to which the embodiments belong. However, embodiments can be embodied in a variety of different forms and are not limited to the embodiments described herein.

[0035] The terms “approximately” and “substantially” as used herein are used in the sense of, or nearly, the numerical tolerances of manufacture and material inherent to the meaning referred to, and are used to prevent unscrupulous infringers from unfairly exploiting disclosures that refer to precise or absolute numerical values ​​in order to understand the specific examples.

[0036] Throughout this specification, the term “these combinations” as used in a Markush expression means one or more mixtures or combinations selected from the group of components described in the Markush expression, and includes one or more selected from the group of components.

[0037] Throughout this specification, the phrase "A and / or B" means "A, B, or A and B."

[0038] Throughout this specification, terms such as “First,” “Second,” or “A,” “B” are used to distinguish between the same terms unless otherwise specified.

[0039] In this specification, the meaning of B being located on A means that B is located on A, or that B is located on A with other layers located between them, or may be located on A, and is not limited to B being located in contact with the surface of A.

[0040] In this specification, singular expressions are to be interpreted as including singular or plural, as interpreted in the context, unless otherwise specified.

[0041] Figure 1 is a cross-sectional view of a blank mask according to one embodiment. Figure 2 is a cross-sectional view of a blank mask according to another embodiment. Figure 3 is a cross-sectional view of a blank mask according to yet another embodiment. Figure 4 is a cross-sectional view of a photomask according to one embodiment. Figure 5 is a diagram showing the process of cleaning the blank mask according to the embodiment.

[0042] The blank mask 100 according to the embodiment includes a light-transmitting substrate 10 and a light-shielding film 20 located on the light-transmitting substrate 10.

[0043] The light-transmitting substrate 10 may have light transmittance to exposure light. The light-transmitting substrate 10 may have a transmittance of more than about 85% to exposure light with a wavelength of about 193 nm. The transmittance of the light-transmitting substrate 20 may be more than about 87%. The transmittance of the light-transmitting substrate 10 may be less than 99.99%. The light-transmitting substrate 10 may contain a synthetic quartz substrate. In this case, the light-transmitting substrate 10 can suppress the attenuation of transmitted light.

[0044] The light-transmitting substrate 10 has surface characteristics such as appropriate flatness and appropriate illuminance, so that distortion of transmitted light can be suppressed.

[0045] The light-shielding film 20 may be placed on the top surface of the light-transmitting substrate 10.

[0046] The light-shielding film 20 can selectively block at least some exposure light incident on the bottom side of the light-transmitting substrate 10.

[0047] Also, Figure 3 As shown, when a phase inversion film 30 or the like is placed between the light-transmitting substrate 10 and the light-shielding film 20, the light-shielding film 20 can be used as an etching mask in the process of etching the phase inversion film 30 or the like according to the pattern shape.

[0048] The light-shielding film 20 may contain at least one of a transition metal, oxygen, and nitrogen.

[0049] The light-shielding film 20 may contain chromium, oxygen, nitrogen, and carbon. The elemental content of the overall light-shielding film 20 may differ from one another in the thickness direction. If the light-shielding film 20 consists of multiple layers, the elemental content of each layer may differ from one another.

[0050] The light-shielding film 20 may contain chromium in an amount of approximately 44 atom% to approximately 60 atom%. The light-shielding film 20 may contain chromium in an amount of approximately 47 atom% to approximately 57 atom%.

[0051] The light-shielding film 20 may contain carbon in an amount of approximately 5 atom% to 30 atom%. The light-shielding film 20 may contain carbon in an amount of approximately 7 atom% to approximately 25 atom%.

[0052] The light-shielding film 20 may contain nitrogen in a content of approximately 3 atom% to approximately 20 atom%. The light-shielding film 20 may contain nitrogen in a content of approximately 5 atom% to approximately 15 atom%. The light-shielding film 20 may contain oxygen in a content of approximately 20 atom% to approximately 45 atom%. The light-shielding film 20 may contain oxygen in a content of approximately 25 atom% to approximately 40 atom%.

[0053] The upper part of the light-shielding film 20 may contain nitrogen in a content of approximately 6 atom% to approximately 16 atom%, chromium in a content of approximately 26 atom% to approximately 46 atom%, oxygen in a content of approximately 37 atom% to approximately 47 atom%, and carbon in a content of approximately 4 atom% to approximately 14 atom%.

[0054] The upper part of the light-shielding film 20 may contain nitrogen in a content of approximately 16 atom% to approximately 26 atom%, chromium in a content of approximately 28 atom% to approximately 40 atom%, oxygen in a content of approximately 27 atom% to approximately 37 atom%, and carbon in a content of approximately 3 atom% to approximately 13 atom%.

[0055] The upper part of the light-shielding film 20 may contain nitrogen in a content of approximately 18 atom% to approximately 27 atom%, chromium in a content of approximately 35 atom% to approximately 41 atom%, oxygen in a content of approximately 31 atom% to approximately 41 atom%, and carbon in a content of approximately 1 atom% to approximately 4 atom%.

[0056] The upper part of the light-shielding film 20 can be defined as extending from the top surface of the light-shielding film 20 to a depth of 1 / 8 of the total thickness of the light-shielding film 20. That is, when the total thickness of the light-shielding film 20 is 8, the upper part of the light-shielding film 20 means extending from the top surface of the light-shielding film 20 to a depth of 1.

[0057] Furthermore, the nitrogen content in the upper part of the light-shielding film 20 can gradually increase. The nitrogen content in the upper part of the light-shielding film 20 can gradually increase from approximately 15 atom% to approximately 25 atom%. In this case, the difference between the minimum and maximum nitrogen content in the upper part of the light-shielding film 20 may be approximately 3 atom% to approximately 8 atom%.

[0058] Furthermore, the chromium content in the upper part of the light-shielding film 20 gradually It can increase The chromium content in the upper part of the light-shielding film 20 can gradually increase from approximately 30 atom% to approximately 40 atom%. In this case, the difference between the minimum and maximum values ​​of the chromium content in the upper part of the light-shielding film 20 may be approximately 3 atom% to approximately 8 atom%.

[0059] Furthermore, the carbon content in the upper part of the light-shielding film 20 may gradually decrease. The carbon content in the upper part of the light-shielding film 20 may gradually decrease from approximately 1 atom% to approximately 7 atom%. In this case, the difference between the minimum and maximum carbon content in the upper part of the light-shielding film 20 may be approximately 0.5 atom% to approximately 5 atom%.

[0060] Furthermore, the content of the oxygen element in the upper part of the light-shielding film 20 may gradually decrease. The content of the oxygen element in the upper part of the light-shielding film 20 may gradually decrease from approximately 35 atom% to approximately 45 atom%. In this case, the difference between the minimum and maximum values ​​of the oxygen element content in the upper part of the light-shielding film 20 may be approximately 4 atom% to approximately 14 atom%.

[0061] In such a case, the light-shielding film 20 can have sufficient quenching properties.

[0062] Figure 2 As shown, the light-shielding film 20 may include a first light-shielding layer 21 and a second light-shielding layer 22 disposed on the first light-shielding layer 21.

[0063] The second light-shielding layer 22 contains a transition metal. The second light-shielding layer 22 may also contain at least one of oxygen, nitrogen, and carbon. The second light-shielding layer 22 may contain a transition metal in a content of about 50 atom% to about 80 atom%. The second light-shielding layer 22 may contain a transition metal in a content of about 55 atom% to about 75 atom%. The second light-shielding layer 22 may contain a transition metal in a content of about 60 atom% to about 70 atom%.

[0064] The content of at least one element corresponding to oxygen, nitrogen, or carbon in the second light-shielding layer 22 may be about 10 atom% to about 35 atom%. The content of at least one element corresponding to oxygen, nitrogen, or carbon in the second light-shielding layer 22 may be about 15 atom% to about 25 atom%.

[0065] The second light-shielding layer 22 may contain nitrogen in a content of approximately 5 atom% to approximately 20 atom%. The second light-shielding layer 22 may contain nitrogen in a content of approximately 7 atom% to approximately 13 atom%.

[0066] The second light-shielding layer 22 may contain oxygen in an amount of approximately 5 atom% to approximately 20 atom%. The second light-shielding layer 22 may contain oxygen in an amount of approximately 7 atom% to approximately 13 atom%.

[0067] The second light-shielding layer 22 may contain carbon in an amount of approximately 2 atom% to approximately 10 atom%. The second light-shielding layer 22 may contain nitrogen in an amount of approximately 37 atom% to approximately 8 atom%.

[0068] The second light-shielding layer 22 may contain nitrogen, oxygen, and carbon.

[0069] In such a case, the light-shielding film 20 can form a laminate together with the phase-inversion film 30, which helps to substantially block the exposure light.

[0070] The first light-shielding layer 21 may contain a transition metal. The first light-shielding layer 21 may contain oxygen and nitrogen. The first light-shielding layer 21 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 21 may contain a transition metal in an amount of 40 atom% or more and 50 atom% or less.

[0071] The sum of the oxygen content and nitrogen content of the first light-shielding layer 21 may be 40 atom% or more and 70 atom% or less. The sum of the oxygen content and nitrogen content of the first light-shielding layer 21 may be 45 atom% or more and 65 atom% or less. The sum of the oxygen content and nitrogen content of the first light-shielding layer 21 may be 50 atom% or more and 60 atom% or less.

[0072] The first light-shielding layer 21 may contain oxygen in an amount of 20 atom% or more and 40 atom% or less. The first light-shielding layer 21 may contain oxygen in an amount of 23 atom% or more and 33 atom% or less. The first light-shielding layer 21 may contain oxygen in an amount of 25 atom% or more and 30 atom% or less.

[0073] The first light-shielding layer 21 may contain nitrogen in an amount of 5 atom% or more and 20 atom% or less. The first light-shielding layer 21 may contain nitrogen in an amount of 7 atom% or more and 17 atom% or less. The first light-shielding layer 21 may contain nitrogen in an amount of 10 atom% or more and 15 atom% or less.

[0074] In such a case, the first light-shielding layer 21 can help the light-shielding film 20 have excellent quenching properties.

[0075] The transition metal may include at least one of Cr, Ta, Ti, and Hf. The transition metal may also be Cr.

[0076] The second light-shielding layer may contain nitrogen in a content of approximately 20 atom% to approximately 40 atom%, chromium in a content of approximately 30 atom% to approximately 50 atom%, and oxygen in a content of approximately 20 atom% to approximately 40 atom%. The second light-shielding layer may also further contain carbon in a content of less than 5 atom%.

[0077] The second light-shielding layer may contain nitrogen in a content of approximately 24 atom% to approximately 34 atom%, chromium in a content of approximately 35 atom% to approximately 45 atom%, and oxygen in a content of approximately 26 atom% to approximately 36 atom%. The second light-shielding layer may also further contain carbon in a content of less than 3 atom%.

[0078] The second light-shielding layer may contain nitrogen in a content of approximately 6 atom% to approximately 16 atom%, chromium in a content of approximately 26 atom% to approximately 46 atom%, oxygen in a content of approximately 37 atom% to approximately 47 atom%, and carbon in a content of approximately 4 atom% to approximately 14 atom%.

[0079] The second light-shielding layer may contain nitrogen in a content of approximately 16 atom% to approximately 26 atom%, chromium in a content of approximately 28 atom% to approximately 40 atom%, oxygen in a content of approximately 27 atom% to approximately 37 atom%, and carbon in a content of approximately 3 atom% to approximately 13 atom%.

[0080] Furthermore, the first light-shielding layer may contain nitrogen in a content of approximately 10 atom% to approximately 30 atom%, chromium in a content of approximately 60 atom% to approximately 90 atom%, and oxygen in a content of approximately 0.5 atom% to approximately atom%. The first light-shielding layer may also contain carbon in a content of less than 5 atom%.

[0081] The composition of the light-shielding film can be measured by X-ray photoelectron spectroscopy (XPS).

[0082] For example, a blank mask according to the example is machined to a size of 15 mm wide by 15 mm high to prepare a specimen. The specimen is then placed in a Thermo Scientific K-Alpha model, and a 4 mm wide by 2 mm high area in the center of the specimen can be etched with argon gas. During the etching time for each layer, the vacuum level inside the measuring equipment is 1.0 × 10⁻⁶. -8 The voltage is mbar, the X-ray source is a Monochromator Al Kα (1486.6 eV), the anode power is 72 W, the anode voltage is 12 kV, and the argon ion beam voltage can be applied at 1 kV.

[0083] Furthermore, regarding the etching time of the light-shielding film, the compositional data from approximately 0 seconds to approximately 30 seconds is inaccurate and can therefore be excluded from the composition of the light-shielding film.

[0084] The thickness of the first light-shielding layer 21 may be approximately 250 Å to approximately 650 Å. The thickness of the first light-shielding layer 21 may be approximately 350 Å to approximately 600 Å. The thickness of the first light-shielding layer 21 may be approximately 400 Å to approximately 550 Å. In such cases, the first light-shielding layer 21 can help the light-shielding film 20 to effectively block exposure light.

[0085] The thickness of the second light-shielding layer 22 may be about 30 Å to about 200 Å. The thickness of the second light-shielding layer 22 may be about 30 Å to about 100 Å. The thickness of the second light-shielding layer 22 may be about 40 Å to about 80 Å. In such cases, the second light-shielding layer 22 can improve the quenching properties of the light-shielding film 20 and help to more precisely control the surface profile of the side surface of the light-shielding pattern film 25 formed during the patterning of the light-shielding film 20.

[0086] The ratio of the thickness of the second light-shielding layer 22 to the thickness of the first light-shielding layer 21 may be about 0.05 to about 0.3. The ratio of the thickness of the second light-shielding layer 22 to the thickness of the first light-shielding layer 21 may be about 0.07 to about 0.25. The ratio of the thickness of the second light-shielding layer 22 to the thickness of the first light-shielding layer 21 may be about 0.1 to about 0.2.

[0087] In such a case, the light-shielding film 20 has sufficient quenching properties, and the surface profile of the side surface of the light-shielding pattern film 25 formed during the patterning of the light-shielding film 20 can be controlled with even greater precision.

[0088] The transition metal content of the second light-shielding layer 22 may be even greater than the transition metal content of the first light-shielding layer 21.

[0089] To further refine the surface profile of the side surface of the light-shielding pattern film 25 formed by patterning the light-shielding film 20, and to ensure that the surface reflectance of the light-shielding film 20 to inspection light in defect inspection is at a value suitable for inspection, the second light-shielding layer 22 is required to have a higher transition metal content than the first light-shielding layer 31.

[0090] However, in such a case, during the heat treatment process of the formed light-shielding film 20, the transition metal contained in the second light-shielding layer 22 may undergo recovery, recrystallization, and grain growth. If grain growth occurs in the second light-shielding layer 22, which contains a high content of transition metal, the surface illuminance characteristics of the light-shielding film 20 may fluctuate excessively due to the overgrown transition metal particles. This can increase the number of detected false defects when inspecting the surface of the light-shielding film 20 for defects with high sensitivity.

[0091] The light-shielding film 20 may have a transmittance of approximately 1% to approximately 2% for light with a wavelength of 193 nm. The light-shielding film 20 may have a transmittance of approximately 1.3% to approximately 2% for light with a wavelength of 193 nm. The light-shielding film 20 may have a transmittance of approximately 1.4% to approximately 2% for light with a wavelength of 193 nm.

[0092] The light-shielding film 20 may have an optical density of about 1.8 to about 3. The light-shielding film 20 may have an optical density of about 1.9 to about 3.

[0093] In such a case, the thin film including the light-shielding film 20 can effectively suppress the transmission of exposure light.

[0094] As shown in Figure 3, the blank mask 100 according to the embodiment may further include a phase inversion film 30.

[0095] The phase inversion film 30 may be placed between the light-transmitting substrate 10 and the light-shielding film 20. The phase inversion film 30 may be a thin film that reduces the intensity of the transmitted exposure light, adjusts the phase difference, and substantially suppresses diffracted light generated at the edges of the pattern.

[0096] The phase inversion film 30 may have a phase difference of approximately 170° to approximately 190° with respect to light with a wavelength of 193 nm. The phase inversion film 40 may have a phase difference of approximately 175° to approximately 185° with respect to light with a wavelength of 193 nm.

[0097] The phase inversion film 30 may have a transmittance of approximately 3% to approximately 10% for light with a wavelength of 193 nm. The phase inversion film 30 may have a transmittance of approximately 4% to approximately 8% for light with a wavelength of 193 nm. In such cases, the resolution of the photomask 200 containing the phase inversion film 30 can be improved.

[0098] The phase inversion film 30 may contain a transition metal and silicon. The phase inversion film 30 may contain a transition metal, silicon, oxygen, and nitrogen. The transition metal may be molybdenum.

[0099] A hard mask (not shown) may be positioned on the light-shielding film 20. The hard mask can function as an etching mask film when etching the pattern of the light-shielding film 20. The hard mask may contain silicon, nitrogen, and oxygen.

[0100] As shown in Figure 4, the photomask 200 according to the embodiment includes the light-transmitting substrate 10 and a light-shielding pattern film 25 disposed on the light-transmitting substrate 10.

[0101] The light-shielding pattern film 25 contains at least one of a transition metal, oxygen, and nitrogen.

[0102] The light-shielding pattern film 25 may be formed by patterning the light-shielding film 20 of the blank mask 100 described above.

[0103] The description of the physical properties, composition, and structure of the light-shielding pattern film 25 is omitted because it overlaps with the description of the light-shielding film 20 of the blank mask 100.

[0104] The method for manufacturing the blank mask 100 according to the example includes the step of forming the light-shielding film 20 on the light-transmitting film. The light-shielding film 20 may be formed by a sputtering process.

[0105] The procedure may include a preparatory step of arranging the light-transmitting substrate and the sputtering target in the sputtering chamber such that the distance between the light-transmitting substrate and the sputtering target is 260 mm or more and 300 mm or less.

[0106] The method for manufacturing the blank mask 100 according to the example may include a film deposition step in which an atmospheric gas is injected into a sputtering chamber, power is applied to the sputtering target, and the light-transmitting substrate is rotated at 25 rpm or more to deposit a light-shielding film 20.

[0107] The aforementioned film formation step may include a process for forming a first light-shielding layer on a light-transmitting substrate, and a process for forming a second light-shielding layer on the first light-shielding layer.

[0108] After the sputtering process is performed, a heat treatment process can be carried out.

[0109] The aforementioned heat treatment step can be carried out at a temperature of approximately 200°C to approximately 400°C.

[0110] The aforementioned heat treatment step can be carried out for approximately 5 to 30 minutes.

[0111] Furthermore, the method for manufacturing the blank mask 100 according to the example may further include a step of freezing the light-shielding film 20 that has undergone the heat treatment step.

[0112] The sputtering target can be selected considering the composition of the light-shielding film 20 to be formed. The sputtering target can be one target containing a transition metal. The sputtering target can include one 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.

[0113] The transition metal may contain at least one of Cr, Ta, Ti, and Hf. The transition metal may also contain Cr.

[0114] In the film deposition step, the rotation speed of the light-transmitting substrate can be set to 25 rpm or higher. The rotation speed can be set to 30 rpm or higher. The rotation speed can be set to 100 rpm or lower. In such cases, the variation in the thickness of the light-shielding film 20 in the in-plane direction can be effectively reduced. Furthermore, the surface illuminance characteristics of each sector within the surface of the light-shielding film 20 can be adjusted to within the range already set in the embodiment.

[0115] The aforementioned atmosphere 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 that constitute the deposited thin film. The reactive gas is a gas that contains the elements that constitute the deposited 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 contain helium.

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

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

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

[0120] The sputtering gas may be Ar gas.

[0121] The power supply used to apply power to the sputtering target can be a DC power supply or an RF power supply.

[0122] In the film formation process of the first light-shielding layer 21, the power applied to the sputtering target can be set to approximately 1.5 kW to approximately 2.5 kW. In the film formation process of the first light-shielding layer 21, the power applied to the sputtering target can be set to approximately 1.6 kW to approximately 2 kW.

[0123] In the film formation process of the first light-shielding layer 21, the ratio of the flow rate of the reactive gas to the flow rate of the inert gas in the atmospheric gas may be about 1.5 to about 3. The ratio of the flow rates may be about 1.8 to about 2.7. The ratio of the flow rates may be about 2 to about 2.5.

[0124] The ratio of oxygen content to nitrogen content in the reactive gas may be about 1.5 to about 4. The ratio of oxygen content to nitrogen content in the reactive gas may be about 2 to about 3. The ratio of oxygen content to nitrogen content in the reactive gas may be about 2.2 to about 2.7.

[0125] In such a case, the first light-shielding layer 21 can help the light-shielding film 20 have sufficient quenching properties. Furthermore, the etching rate of the first light-shielding layer 21 can be improved to help the surface profile of the side surface of the light-shielding pattern film 25 formed by patterning the light-shielding film 20 have a shape that is nearly perpendicular to the light-transmitting substrate 10.

[0126] The deposition time for the first light-shielding layer 21 may be approximately 200 seconds to approximately 300 seconds. The deposition time for the first light-shielding layer 21 may also be approximately 210 seconds to approximately 240 seconds. In such cases, the first light-shielding layer 21 can help the light-shielding film 20 to have sufficient quenching properties.

[0127] In the process of forming the second light-shielding layer 22, the power applied to the sputtering target can be set to approximately 1kW to approximately 2kW. In the process of forming the second light-shielding layer 22, the power applied to the sputtering target can be set to approximately 1.2kW to approximately 1.7kW.

[0128] In the film formation process of the second light-shielding layer 22, the ratio of the flow rate of the reactive gas to the flow rate of the inert gas in the atmospheric gas may be about 0.3 to about 0.8. The ratio of the flow rates may be about 0.4 to about 0.6.

[0129] In the film formation process of the second light-shielding layer 22, the ratio of oxygen content to nitrogen content in the reactive gas may be less than approximately 0.3. The ratio of oxygen content to nitrogen content in the reactive gas may be less than approximately 0.1. The ratio of oxygen content to nitrogen content in the reactive gas may be greater than 0.001. As described above, the second light-shielding layer 22 is formed, and the light-shielding film 20 may have stable quenching properties.

[0130] The deposition time for the second light-shielding layer 22 may be approximately 10 seconds to approximately 30 seconds. The deposition time for the second light-shielding layer 22 may also be approximately 15 seconds to approximately 25 seconds. In such cases, the second light-shielding layer 22 can suppress the transmission of exposure light.

[0131] In the heat treatment step, multiple areas on the surface of the light-shielding film 20 can be heat-treated at independently controlled temperatures. Specifically, a heater may be installed for each area on the surface of the light-shielding film 20. The area-specific heaters may be installed on the light-transmitting substrate side.

[0132] The temperature of each of the zone heaters can be independently controlled within a range of approximately 200°C to 400°C.

[0133] The blank mask 100 can undergo a cooling step within 2 minutes after the heat treatment step is completed. In this case, the growth of crystal grains of the transition metal particles due to residual heat within the light-shielding film 20 can be effectively prevented.

[0134] In the cooling stage described above, pins having a predetermined length are provided at each corner of the cooling plate, and the blank mask 100 is positioned on the pins so that the substrate faces the cooling plate, thereby allowing the cooling speed of the blank mask 100 according to the embodiment to be controlled.

[0135] In the above cooling stage, the cooling temperature applied to the cooling plate may be approximately 10°C to approximately 30°C. The above cooling temperature may also be approximately 15°C to approximately 25°C.

[0136] In the cooling step described above, the separation distance between the blank mask 100 and the cooling plate according to the embodiment may be approximately 0.01 mm to approximately 30 mm. The separation distance may be 0.05 mm or more and 5 mm or less. The separation distance may be 0.1 mm or more and 2 mm or less.

[0137] The above cooling stage can be performed for approximately 1 to 10 minutes. The above cooling stage can be performed for approximately 3 to 7 minutes.

[0138] The cooled light-shielding film 20 can then be washed. The washing step may include an ultraviolet irradiation step and / or a rinsing step.

[0139] The above ultraviolet irradiation step may include a step of irradiating the light-shielding film 20 with ultraviolet light.

[0140] The ultraviolet light used in the above ultraviolet irradiation process may be vacuum ultraviolet light. The ultraviolet light used in the above ultraviolet irradiation process may also be ultraviolet light having a peak wavelength band of approximately 100 nm to approximately 190 nm.

[0141] The above ultraviolet irradiation process can be carried out at room temperature and under relative humidity conditions of approximately 30% to 60%. The above ultraviolet irradiation process can also be carried out at room temperature and under relative humidity conditions of approximately 40% to 50%.

[0142] In the above ultraviolet irradiation process, the output of the ultraviolet light irradiated onto the light-shielding film 20 is approximately 5 mW / cm². 2 ~about 100mW / cm 2 This may also be the case. In the above ultraviolet irradiation process, the output of the ultraviolet light irradiated onto the light-shielding film 20 is approximately 10 mW / cm². 2 ~about 70mW / cm 2 That's fine.

[0143] In the above ultraviolet irradiation step, the time for irradiating the light-shielding film 20 with ultraviolet light may be approximately 10 seconds to approximately 10 minutes. In the above ultraviolet irradiation step, the time for irradiating the light-shielding film 20 with ultraviolet light may be approximately 10 seconds to approximately 5 minutes. In the above ultraviolet irradiation step, the time for irradiating the light-shielding film 20 with ultraviolet light may be approximately 1 minute to approximately 10 minutes. In the above ultraviolet irradiation step, the time for irradiating the light-shielding film 20 with ultraviolet light may be approximately 10 seconds to approximately 1 minute.

[0144] Furthermore, in the ultraviolet irradiation process described above, nitrogen gas (N2) or oxygen gas (O2) can be used as the ambient gas.

[0145] The above rinsing step includes the step of treating the light-shielding film 20 with a cleaning solution. The cleaning solution may contain at least one of deionized water, hydrogen water, ozonated water, or carbonated water. The cleaning solution may contain carbonated water.

[0146] The carbon dioxide concentration in the carbonated water may be approximately 500 mg / l to approximately 5000 mg / l. The carbon dioxide concentration in the carbonated water may be approximately 1000 mg / l to approximately 3000 mg / l.

[0147] The ozone concentration in the ozonated water may be approximately 50 mg / l to approximately 2000 mg / l. The ozone concentration in the ozonated water may be approximately 100 mg / l to approximately 1000 mg / l.

[0148] The hydrogen concentration in the hydrogen water may be approximately 0.1 mg / l to approximately 10 mg / l. The hydrogen concentration in the hydrogen water may be approximately 0.5 mg / l to approximately 5 mg / l.

[0149] The above cleaning solution treatment step may include the step of immersing the blank mask 100 according to the example in the cleaning solution. The above cleaning solution treatment step may also include the step of spraying and rinsing the cleaning solution onto the light-shielding film 20.

[0150] In the above cleaning solution treatment stage, the process time may be approximately 1 minute to approximately 10 minutes. In the above cleaning solution treatment stage, the process time may be approximately 2 minutes to approximately 7 minutes.

[0151] Subsequently, during the cleaning solution treatment step, the light-shielding film 20 may be irradiated with ultraviolet light. That is, the rinsing step and the ultraviolet irradiation step can be performed simultaneously. After the ultraviolet irradiation step, the rinsing step can be performed. At this time, while the rinsing step is being performed, the light-shielding film 20 may be irradiated with ultraviolet light in a manner similar to that of the ultraviolet irradiation step.

[0152] After the rinsing process described above is performed, the blank mask 100 according to the example can be dried.

[0153] Figure 5 As shown above, the thickness of the light-shielding film 20 may change during the cleaning process. That is, during the cleaning process, a portion of the light-shielding film 20 may be removed, reducing its thickness. In the cleaning process, the change in the thickness of the light-shielding film 20 (△T) may be the difference between the thickness before the cleaning process and the thickness after the cleaning process.

[0154] In the above cleaning process, the change in thickness of the light-shielding film 20 may be less than approximately 15 nm. In the above cleaning process, the change in thickness of the light-shielding film 20 may be less than approximately 5 nm. In the above cleaning process, the change in thickness of the light-shielding film 20 may be less than approximately 4 nm. In the above cleaning process, the change in thickness of the light-shielding film 20 may be less than approximately 3 nm. In the above cleaning process, the change in thickness of the light-shielding film 20 may be less than approximately 2.5 nm. In the above cleaning process, the change in thickness of the light-shielding film 20 may be less than approximately 2 nm. In the above cleaning process, the change in thickness of the light-shielding film 20 may be less than approximately 1.5 nm.

[0155] In the above cleaning process, the change in the thickness of the light-shielding film 20 may be approximately 0.3 nm to approximately 3 nm, or approximately 0.1 nm to approximately 1 nm.

[0156] In the above cleaning step, the change in thickness of the light-shielding film 20 may be about 0.1 nm to about 5 nm. In the above cleaning step, the change in thickness of the light-shielding film 20 may be about 0.2 nm to about 5 nm. In the above cleaning step, the change in thickness of the light-shielding film 20 may be about 0.3 nm to about 5 nm. In the above cleaning step, the change in thickness of the light-shielding film 20 may be about 0.1 nm to about 3 nm. In the above cleaning step, the change in thickness of the light-shielding film 20 may be about 0.2 nm to about 3 nm. In the above cleaning step, the change in thickness of the light-shielding film 20 may be about 0.3 nm to about 3 nm.

[0157] In the above cleaning process, the change in thickness of the light-shielding film 20 may be approximately 3 nm to approximately 15 nm. In the above cleaning process, the change in thickness of the light-shielding film 20 may be approximately 3 nm to approximately 8 nm. In the above cleaning process, the change in thickness of the light-shielding film 20 may be approximately 5 nm to approximately 15 nm.

[0158] In the above cleaning step, the thickness of the light-shielding film 20 in the above film formation step can be determined by taking into consideration the change in the thickness of the light-shielding film 20.

[0159] In the above cleaning process, the change in the thickness of the light-shielding film 20 may be a change in the thickness of the second light-shielding layer 22.

[0160] In the above cleaning process, since the change in the thickness of the light-shielding film 20 has an appropriate range as described above, the change in the optical properties of the light-shielding film 20 can also have an appropriate range.

[0161] In the above cleaning process, the change in the thickness of the light-shielding film 20 is the same as described above, so the change in the optical properties of the light-shielding film 20 can be minimized.

[0162] During the above cleaning process, a change in the transmittance of the light-shielding film 20 may occur. The change in the transmittance of the light-shielding film 20 may be the difference between the transmittance before the cleaning process and the transmittance after the cleaning process. The transmittance of the light-shielding film 20 can be measured using light in the wavelength band of approximately 193 nm.

[0163] In the above cleaning process, the change in transmittance of the light-shielding film 20 may be less than approximately 0.03%. In the above cleaning process, the change in transmittance of the light-shielding film 20 may be less than approximately 0.02%. In the above cleaning process, the change in transmittance of the light-shielding film 20 may be less than approximately 0.01%. In the above cleaning process, the change in transmittance of the light-shielding film 20 may be less than approximately 0.007%. In the above cleaning process, the change in transmittance of the light-shielding film 20 may be less than approximately 0.005%. In the above cleaning process, the change in transmittance of the light-shielding film 20 may be less than approximately 0.003%.

[0164] In the above cleaning process, the change in transmittance of the light-shielding film 20 may be approximately 0.005% to approximately 0.02%.

[0165] In the above cleaning process, the minimum value of the change in transmittance of the light-shielding film 20 may be approximately 0.00001%.

[0166] In the above cleaning process, the change in transmittance of the light-shielding film 20 is the same as described above, so the light-shielding film 20 can reduce the deviation in transmittance at different positions. As a result, the blank mask 100 according to the embodiment can provide a precise photomask.

[0167] During the above cleaning process, a change in the optical density of the light-shielding film 20 may occur. The change in the optical density of the light-shielding film 20 may be the difference between the optical density before the cleaning process and the optical density after the cleaning process. The optical density can be measured using an optical density meter such as the Linshang LS117.

[0168] In the above cleaning process, the change in optical density of the light-shielding film 20 may be less than approximately 0.1. In the above cleaning process, the change in optical density of the light-shielding film 20 may be less than approximately 0.07. In the above cleaning process, the change in optical density of the light-shielding film 20 may be less than approximately 0.05. In the above cleaning process, the change in optical density of the light-shielding film 20 may be less than approximately 0.03. In the above cleaning process, the change in optical density of the light-shielding film 20 may be less than approximately 0.02.

[0169] In the above cleaning process, the change in optical density of the light-shielding film 20 may be approximately 0.01 to approximately 0.08.

[0170] In the above cleaning process, the change in optical density of the light-shielding film 20 is the same as described above, so the light-shielding film 20 can reduce the deviation in optical density at different positions. As a result, the blank mask 100 according to the embodiment can provide a precise photomask.

[0171] During the cleaning process described above, a change in the reflectance of the light-shielding film 20 may occur. The change in the reflectance of the light-shielding film 20 may be the difference between the reflectance before the cleaning process and the reflectance after the cleaning process. The reflectance can be measured using light in the wavelength range of approximately 193 nm.

[0172] In the above cleaning process, the change in reflectance of the light-shielding film 20 may be less than approximately 0.5%. In the above cleaning process, the change in reflectance of the light-shielding film 20 may be less than approximately 0.4%. In the above cleaning process, the change in reflectance of the light-shielding film 20 may be less than approximately 0.3%. In the above cleaning process, the change in reflectance of the light-shielding film 20 may be less than approximately 0.2%.

[0173] In the above cleaning process, the minimum value of the change in reflectance of the light-shielding film 20 may be approximately 0.01%.

[0174] In the above cleaning process, the change in reflectance of the light-shielding film 20 is the same as described above, so the light-shielding film 20 can reduce the deviation in reflectance at different positions. As a result, the blank mask 100 according to the embodiment can provide a precise photomask.

[0175] The blank mask 100 according to the example may have a low ion concentration on its surface.

[0176] The halogen ion content on the entire surface of the blank mask 100 according to the example was 0.15 ng / cm³. 2 It may be less than 0.10 ng / cm³. The halogen ion content on the entire surface of the blank mask 100 according to the example is 0.10 ng / cm³. 2 It may be less than 0.07 ng / cm³. The halogen ion content on the entire surface of the blank mask 100 according to the example is 0.07 ng / cm³. 2 It may be less than 0.05 ng / cm³. The halogen ion content on the entire surface of the blank mask 100 according to the example is 0.05 ng / cm³. 2 It is acceptable to be less than [a certain value].

[0177] The aforementioned halogen ions may include chloride ions.

[0178] The nitrogen ion content on the entire surface of the blank mask 100 in the example was 3 ng / cm³. 2 It may be less than 2.5 ng / cm³. The nitrogen ion content on the entire surface of the blank mask 100 according to the example is 2.5 ng / cm³. 2 It may be less than 2 ng / cm³. The nitrogen ion content on the entire surface of the blank mask 100 according to the example is 2 ng / cm³. 2 It may be less than 1.8 ng / cm³. The nitrogen ion content on the entire surface of the blank mask 100 according to the example is 1.8 ng / cm³. 2 It may be less than 1.5 ng / cm³. The nitrogen ion content on the entire surface of the blank mask 100 according to the example is 1.5 ng / cm³. 2 It is acceptable to be less than [a certain value].

[0179] The aforementioned nitrogen-based ions include nitrite ions, nitric acid It may contain ions and ammonia.

[0180] The sulfur ion content on the entire surface of the blank mask 100 in the example was approximately 0.2 ng / cm³. 2 It may be less than 0.17 ng / cm³. The sulfur ion content on the entire surface of the blank mask 100 according to the example is approximately 0.17 ng / cm³. 2 It may be less than 0.1 ng / cm³. The sulfur ion content on the entire surface of the blank mask 100 according to the example is approximately 0.1 ng / cm³. 2 It may be less than 0.07 ng / cm³. The sulfur ion content on the entire surface of the blank mask 100 according to the example is approximately 0.07 ng / cm³. 2 It is acceptable to be less than [a certain value].

[0181] The aforementioned sulfur-based ions may include sulfate ions.

[0182] Furthermore, the acetate content on the entire surface of the blank mask 100 according to the example was 0.02 ng / cm³. 2It may be less than 0.02 ng / cm³. The oxalic acid content on the entire surface of the blank mask 100 according to the example is 0.02 ng / cm³. 2 It may be less than 0.02 ng / cm³. The sodium content on the entire surface of the blank mask 100 according to the example is 0.02 ng / cm³. 2 It may be less than 0.02 ng / cm³. The potassium content on the entire surface of the blank mask 100 according to the example is 0.02 ng / cm³. 2 It may be less than 0.02 ng / cm³. The magnesium content on the entire surface of the blank mask 100 according to the example is 0.02 ng / cm³. 2 It may be less than 0.02 ng / cm³. The calcium content on the overall surface of the blank mask 100 according to the example is 0.02 ng / cm³. 2 It is acceptable to be less than [a certain value].

[0183] As described above, the blank mask 100 according to the example has a low surface ion concentration, which suppresses defects and provides a photomask of improved quality.

[0184] In the blank mask 100 according to the example, the surface ion concentration can be measured by ion chromatography. The blank mask 100 according to the example can be immersed in deionized water, allowing ions to elute over a sufficient period of time, and the content of the elutenated ions can be measured.

[0185] In the blank mask 100 according to the example, the change in the thickness of the light-shielding film 20 measured by the following measurement method may be less than approximately 2 nm.

[0186] [Measurement method] The light-shielding film 20 is immersed in carbonated water having a carbon dioxide concentration of approximately 2000 mg / l for approximately 10 minutes, and the change in the thickness of the light-shielding film 20 is the difference between the thickness of the light-shielding film 20 before immersion and the thickness after immersion.

[0187] The thickness change may be less than approximately 20 nm. The thickness change may be less than approximately 15 nm. The thickness change may be less than approximately 10 nm. The thickness change may be less than approximately 7 nm. The thickness change may be less than approximately 5 nm. The thickness change may be less than approximately 4 nm. The thickness change may be less than approximately 3 nm. The thickness change may be less than approximately 2.5 nm. The thickness change may be less than approximately 2 nm. The thickness change may be less than approximately 1.55 nm.

[0188] The thickness variation may be approximately 0.1 nm to approximately 10 nm. The thickness variation may be approximately 0.1 nm to approximately 7 nm. The thickness variation may be approximately 0.1 nm to approximately 5 nm. The thickness variation may be approximately 0.1 nm to approximately 4 nm. The thickness variation may be approximately 0.1 nm to approximately 3 nm. The thickness variation may be approximately 0.1 nm to approximately 2.5 nm. The thickness variation may be approximately 0.1 nm to approximately 2 nm. The thickness variation may be approximately 0.1 nm to approximately 1.55 nm.

[0189] The aforementioned thickness variation may be 0.3 nm to 3 nm, or 0.1 nm to 1 nm.

[0190] The thickness variation may be approximately 3 nm to approximately 15 nm. The thickness variation may be approximately 3 nm to approximately 8 nm. The thickness variation may be approximately 7 nm to approximately 15 nm.

[0191] The aforementioned thickness change may also be a change in the thickness of the second light-shielding layer 22.

[0192] Furthermore, the blank mask 100 according to the embodiment may have a change in transmittance. The change in transmittance can be derived by the measurement method described above. The change in transmittance is the difference between the transmittance of the light-shielding film 20 before immersion and the transmittance after immersion.

[0193] The aforementioned change in transmittance may be less than approximately 0.3%. The aforementioned change in transmittance may be less than approximately 0.2%. The aforementioned change in transmittance may be less than approximately 0.1%. The aforementioned change in transmittance may be less than approximately 0.05%. The minimum value of the aforementioned change in transmittance may be approximately 0.00001%.

[0194] The aforementioned change in transmittance may be approximately 0.003% to approximately 0.02%.

[0195] Furthermore, the blank mask 100 according to the embodiment may have a change in optical density. The change in optical density can be derived by the measurement method described above.

[0196] The optical density change may be less than 0.1. The optical density change may be less than 0.08. The optical density change may be less than 0.07. The optical density change may be less than 0.05. The optical density change may be less than 0.03. The optical density change may be less than 0.02. The minimum value of the optical density change may be about 0.0001.

[0197] The optical density change may be between 0.01 and 0.07. The optical density change may be between 0.01 and 0.04. The optical density change may be between 0.03 and 0.07.

[0198] Furthermore, the blank mask 100 according to the embodiment may have a change in reflectance. The change in reflectance can be derived by the measurement method described above.

[0199] The change in reflectance may be less than approximately 0.3%. The change in reflectance may be less than approximately 0.2%. The change in reflectance may be less than approximately 0.1%. The change in reflectance may be less than approximately 0.08%. The change in reflectance may be less than approximately 0.05%. The minimum value of the change in reflectance may be approximately 0.0001%.

[0200] As described above, the blank mask 100 according to the embodiment exhibits low changes in thickness, transmittance, optical density, and reflectance after immersion in the carbonated water. This allows the blank mask 100 according to the embodiment to minimize changes in optical properties during processes such as the cleaning step in the manufacturing process of the photomask.

[0201] The method for manufacturing a semiconductor device according to the embodiment includes a preparation step of arranging a light source, a photomask 200, 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 200 onto the semiconductor wafer; and a development step of developing a pattern on the semiconductor wafer.

[0202] The photomask 200 includes a light-transmitting substrate 10 and a light-shielding pattern film 35 disposed on the light-transmitting substrate 10.

[0203] The light-shielding pattern film 25 contains at least one of a transition metal, oxygen, nitrogen, and carbon.

[0204] In the above preparation stage, the light source is a device capable of generating short-wavelength exposure light. The exposure light may be light with a wavelength of 200 nm or less. The exposure light may also be ArF light with a wavelength of 193 nm.

[0205] A lens may be further placed between the photomask 200 and the semiconductor wafer. The lens functions to reduce the shape of the circuit pattern on the photomask 200 and transfer it onto the semiconductor wafer. The lens is not limited as long as it is generally applicable to the exposure process of ArF semiconductor wafers. For example, the lens may be made of calcium fluoride (CaF2).

[0206] In the exposure step described above, exposure light can be selectively transmitted onto the semiconductor wafer through the photomask 200. In such a case, chemical modification may occur in the portion of the resist film that is incident on by the exposure light.

[0207] In the development step described above, the semiconductor wafer that has completed the exposure step can be treated with a developing solution to develop a pattern on the semiconductor wafer. If the coated resist film is a positive resist, the portion of the resist film that has been exposed to light can be dissolved by the developing solution. If the coated resist film is a negative resist, the portion of the resist film that has not been exposed to light can be dissolved by the developing solution. Through treatment with the developing solution, the resist film is formed into a resist pattern. Using this resist pattern as a mask, a pattern can be formed on the semiconductor wafer.

[0208] The explanation regarding the aforementioned photomask 200 is omitted as it would be redundant with the above content.

[0209] The following sections will provide a more detailed explanation of specific examples.

[0210] Example 1 A light-transmitting quartz substrate measuring 6 inches wide, 6 inches long, and 0.25 inches thick was placed inside a chamber equipped with DC sputtering equipment. A chromium target was positioned inside the chamber so that the T / S distance was 200 mm and the angle between the substrate and the target was 45 degrees. The temperature of the chamber rose to approximately 400°C.

[0211] Subsequently, an atmospheric gas mixture containing 21% by volume of Ar, 11% by volume of N2, 32% by volume of CO2, and 36% by volume of He was introduced into the chamber. A power of 1.85 kW was applied to the sputtering target, and the substrate rotation speed was set to 30 rpm. The sputtering process was carried out for 250 seconds to deposit the first light-shielding layer.

[0212] After completing the deposition of the first light-shielding layer, an atmospheric gas mixture containing 57% by volume of Ar, 33% by volume of N2, and 10% by volume of CO2 was introduced into the chamber. A power of 1.5 kW was applied to the sputtering target, and the substrate rotation speed was set to 30 rpm. A sputtering process was carried out for 45 seconds to produce a blank mask specimen with a second light-shielding layer deposited.

[0213] The specimens in which the second light-shielding layer had been deposited were placed in a heat treatment chamber, and the heater temperature was set to approximately 300°C for approximately 15 minutes during the heat treatment.

[0214] A cooling plate with a cooling temperature of 23°C was placed on the substrate side of the heat-treated specimen. Then, a cooling gas was injected through a nozzle at a flow rate of 50 sccm, and a cooling process was carried out for 5 minutes. Helium was used as the cooling gas.

[0215] Subsequently, vacuum ultraviolet light with a wavelength band of approximately 185 nm is applied to the upper surface of the light-shielding film at a rate of approximately 40 mW / cm². 2 The irradiation was performed at this intensity for approximately one minute in a chamber under vacuum pressure.

[0216] Subsequently, carbonated water (carbon dioxide concentration, 2000 mg / l) was flowed over the light-shielding film that had undergone the above ultraviolet treatment. Simultaneously, the light-shielding film was also irradiated with vacuum ultraviolet light under the same conditions as above. The rinsing process with carbonated water was performed for approximately 1 minute.

[0217] Subsequently, the cleaning solution, which was a mixture of carbonated water and hydrogen water (hydrogen concentration, 1.6 mg / l) in a ratio of approximately 1:1, was flowed over the light-shielding film for approximately 30 seconds to perform a surface cleaning process.

[0218] Subsequently, the blank masks from the examples were dried.

[0219] Examples 2-4 and Comparative Example 1 The film formation and cleaning conditions for the second light-shielding layer were as shown in Tables 1 and 2 below, and other steps were as described in Example 1. The ozone concentration in the ozonated water was approximately 200 mg / l.

[0220] Examples 5 to 8 A light-transmitting quartz substrate measuring 6 inches wide, 6 inches long, and 0.25 inches thick was placed inside a chamber equipped with DC sputtering equipment. A chromium target was positioned inside the chamber so that the T / S distance was 200 mm and the angle between the substrate and the target was 45 degrees. The temperature of the chamber rose to approximately 400°C.

[0221] Subsequently, an atmospheric gas mixture of 57% by volume Ar and 43% by volume N2 was introduced into the chamber, a power of 1.35 kW was applied to the sputtering target, and a substrate rotation speed of 30 rpm was applied. The sputtering process was carried out for 430 seconds to deposit the first light-shielding layer.

[0222] After completing the deposition of the first light-shielding layer, an atmospheric gas mixture containing 15% by volume of Ar, 72% by volume of N2, and 13% by volume of O2 was introduced into the chamber. A power of 1.85 kW was applied to the sputtering target, and the substrate rotation speed was set to 30 rpm. A sputtering process was carried out for 210 seconds to produce a blank mask specimen with a second light-shielding layer deposited.

[0223] After the light-shielding layer was formed, the heat treatment, cooling, and cleaning steps were carried out in the same manner as in Example 1.

[0224] Furthermore, in Examples 6 to 8, the film formation conditions and cleaning conditions for the second light-shielding layer were carried out as shown in Tables 1 and 2 below, and the other steps were carried out as in Example 5. In addition, in Examples 7 and 8, helium gas was applied at approximately 34% by volume and approximately 32% by volume, respectively.

[0225] Example 9 A light-transmitting quartz substrate measuring 6 inches wide, 6 inches long, and 0.25 inches thick was placed inside a chamber equipped with DC sputtering equipment. A chromium target was positioned inside the chamber so that the T / S distance was 200 mm and the angle between the substrate and the target was 45 degrees. The temperature of the chamber rose to approximately 400°C.

[0226] The chamber was filled with argon gas and nitrogen gas in a volume ratio of approximately 15:35. Subsequently, while maintaining the ratio of argon gas and nitrogen gas inside the chamber, a single sputtering process was carried out for approximately 30 seconds at a power of approximately 1.4 kW.

[0227] Subsequently, the sputtering power was increased from approximately 1.4 kW to approximately 1.8 kW, and a two-stage sputtering process was carried out for approximately 80 seconds while argon gas, nitrogen gas, and carbon dioxide flowed into the chamber in a volume ratio of 2:2:1.

[0228] Subsequently, a three-stage sputtering process was carried out for approximately 100 seconds. During the three-stage sputtering process, the volume ratios of the gases introduced into the chamber were adjusted so that the volume ratio of argon gas, helium gas, nitrogen gas, oxygen gas, and carbon dioxide gas in the chamber gradually changed from approximately 2:2:0:0:1 to approximately 2:2:4:4:1. Throughout the three-stage sputtering process, the sputtering power was continuously reduced from approximately 1.8 kW to approximately 1.4 kW.

[0229] Subsequently, a four-stage sputtering process was carried out for approximately 60 seconds. During the four-stage sputtering process, the sputtering power was maintained at approximately 1.4 kW. In addition, during the four-stage sputtering process, the volume ratios of the gases introduced into the chamber were adjusted so that the volume ratio of argon gas, helium gas, nitrogen gas, oxygen gas, and carbon dioxide gas in the chamber gradually changed from approximately 2:2:4:4:1 to 2:2:2:5:1.

[0230] After the light-shielding layer was formed, the heat treatment, cooling, and cleaning steps were carried out in the same manner as in Example 1.

[0231] [Table 1]

[0232] [Table 2]

[0233] Evaluation example 1. Surface ion concentration The blank masks produced in the examples and comparative examples were placed in a clean bag, and approximately 100 ml of deionized water was added to the clean bag. The clean bag containing the blank masks was then left at approximately 90°C for approximately 120 minutes. The ion concentrations eluted from the blank masks were then analyzed using ion chromatography equipment (Thermo SCIENTIFIC's Dionex ICS-2100). The eluted ion concentrations relative to the surface area of ​​the blank masks are shown in Table 3 below. Fluorine, acetate, formate, oxalate, sodium, potassium, magnesium, and calcium were not detected.

[0234] 2. Measurement of changes in thickness, transmittance, optical density, and reflectance. The changes in thickness, transmittance, optical density, and reflectance of the light-shielding film before and after cleaning were measured and are shown in Table 4 below.

[0235] The blank masks produced in the examples and comparative examples were immersed in carbonated water with a carbon dioxide concentration of approximately 2000 mg / l for about 10 minutes.

[0236] The changes in thickness, transmittance, optical density, and reflectance of the light-shielding film before and after immersion were measured and are shown in Table 5 below.

[0237] The thickness, transmittance, optical density, and reflectance of the aforementioned light-shielding film were measured at 23 locations and derived as average values.

[0238] The thickness, transmittance, optical density, and reflectance of the aforementioned light-shielding film were measured using Nanobu's MG-PRO.

[0239] The aforementioned transmittance and reflectance were measured for light in the wavelength range of approximately 193 nm.

[0240] 3. Composition of the light-shielding layer The composition of the light-shielding layer is measured by X-ray photoelectron spectroscopy (XPS).

[0241] The blank masks produced in the examples and comparative examples were processed to a size of 15 mm wide by 15 mm high to prepare test specimens. These specimens were then placed in a Thermo Scientific K-Alpha model, and a 4 mm wide by 2 mm high area in the center of the specimen was etched with argon gas. During the etching time for each layer, the vacuum level inside the measuring equipment was 1.0 × 10⁻⁶. -8 The voltage was mbar, the X-ray source was a Monochromator Al Kα (1486.6 eV), the anode power was 72 W, the anode voltage was 12 kV, and the argon ion beam voltage was 1 kV.

[0242] The composition of the second light-shielding layer during etching times from approximately 30 seconds to approximately 80 seconds is measured using the above-mentioned measuring equipment as shown in Table 6 below.

[0243] Furthermore, in Example 9, the composition of the upper part of the light-shielding layer was measured using the above-mentioned measuring equipment as shown in Table 7 below, with etching times ranging from approximately 30 seconds to approximately 84 seconds.

[0244] [Table 3]

[0245] [Table 4]

[0246] [Table 5]

[0247] [Table 6]

[0248] [Table 7]

[0249] As shown in Tables 3 to 7, the blank masks according to the examples have a low surface ion concentration and exhibit small changes in thickness, transmittance, optical density, and reflectance. [Explanation of Symbols]

[0250] 100 Blank Masks 10 Light-transparent substrate 20 Light-shielding film 21 1st light shielding layer 22 Second light shielding layer 25 Light-shielding pattern film 30 Phase Inversion Film 200 Photomasks

Claims

1. The steps include forming a light-shielding film on a light-transmitting substrate, The steps include washing the light-shielding film with a cleaning solution, Includes, The aforementioned cleaning step is, The light-shielding film is rinsed with carbonated water having a carbon dioxide concentration of 500 mg / l to 5000 mg / l. The step includes surface cleaning the light-shielding film with at least two of the following: carbonated water, hydrogen water, and ozonated water. The change in the thickness of the light-shielding film during the cleaning step is 0.3 nm to 3 nm. The acetate content on the entire surface is 0.02 ng / cm³. ２ The oxalic acid content is less than 0.02 ng / cm³. ２ The chloride ion content is less than 0.1 ng / cm³. ２ The levels are less than 3 ng / cm³, and the content of nitrite ions, nitrate ions, and ammonia is 3 ng / cm³. ２ The sulfate ion content is less than 0.2 ng / cm³. ２ A method for manufacturing a blank mask, wherein the ion content is less than the following measurement method. [Measurement method] The blank mask is placed in a clean bag, 100 ml of deionized water is added to the clean bag, and the blank mask is left at 90°C for 120 minutes. After that, the concentration of eluted ions is measured.

2. The process further includes the step of forming a phase inversion film on the light-transmitting substrate, The light-shielding film is formed on the phase inversion film, A method for manufacturing a blank mask according to claim 1.

3. The change in transmittance of the light-shielding film during the above cleaning step is less than 0.05%. A method for manufacturing a blank mask according to claim 1.

4. The change in optical density of the light-shielding film during the above cleaning step is less than 0.

07. A method for manufacturing a blank mask according to claim 3.

5. The change in reflectivity of the light-shielding film during the above cleaning stage is less than 0.5%. A method for manufacturing a blank mask according to claim 4.

6. The aforementioned light-shielding film is A first light-shielding layer disposed on the light-transmitting substrate, A second light-shielding layer is disposed on the first light-shielding layer, Includes, The second light-shielding layer contains nitrogen in a content of 20 atom% to 40 atom%, chromium in a content of 30 atom% to 50 atom%, and oxygen in a content of 20 atom% to 40 atom%. A method for manufacturing a blank mask according to claim 1.

7. The first light-shielding layer contains nitrogen in a content of 10 atom% to 30 atom%, chromium in a content of 60 atom% to 90 atom%, and oxygen in a content of 0.5 atom% to 10 atom%. A method for manufacturing a blank mask according to claim 6.

8. The second light-shielding layer contains carbon in a content of less than 5 atom%, A method for manufacturing a blank mask according to claim 6.

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