Blank mask, photomask, and method for manufacturing semiconductor element

Abstract

This invention relates to a blank mask, a photomask, and a method for manufacturing a semiconductor device. According to this embodiment, the blank mask includes a light-transmitting substrate and a light-shielding film disposed on the light-transmitting substrate. The light-shielding film includes at least one of a transition metal, oxygen, and nitrogen. When the optical density of the light-shielding film is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density values ​​is less than or equal to 0.009. The value obtained by subtracting the minimum value from the maximum value of the measured optical density values ​​is less than 0.03. The Rsk value of the surface of the light-shielding film is greater than or equal to -2 and less than or equal to 0.1. Under these conditions, optical characteristic measurements and defect detection of the light-shielding film of the blank mask can be performed with improved accuracy.

Description

Technical Field

[0001] This embodiment relates to a method for manufacturing blank masks, photomasks, and semiconductor devices. Background Technology

[0002] With the increasing integration of semiconductor devices, there is a growing demand for miniaturizing the circuit patterns within these devices. Therefore, photolithography, a technique that uses photomasks to develop circuit patterns on wafer surfaces, has become increasingly important.

[0003] To develop finely detailed circuit patterns, it is necessary to shorten the wavelength of the exposure light source used in the exposure process. Recently used exposure light sources include ArF excimer lasers (wavelength 193 nm).

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

[0005] A binary photomask has a structure in which a light-shielding layer pattern is formed on a transparent substrate. On the patterned surface of the binary photomask, the transmissive portion excluding the light-shielding layer allows exposure light to pass through, while the light-shielding portion including the light-shielding layer blocks the exposure light, thereby exposing the pattern on the resist film on the wafer surface. However, in binary photomasks, as the pattern becomes finer, problems may arise during the development of the finer pattern due to light diffraction at the edges of the transmissive portion during the exposure process.

[0006] Phase-shifting masks include Levenson type, Outrigger type, and Half-tone type. Half-tone type phase-shifting masks have a structure in which a pattern formed by a semi-transparent film is formed on a transparent substrate. On the patterned surface of the half-tone type phase-shifting mask, the transmissive portion excluding the semi-transparent layer allows exposure light to pass through, while the semi-transmissive portion including the semi-transparent layer allows attenuated exposure light to pass through. The attenuated exposure light has a phase difference compared to the exposure light transmitted through the transmissive portion. Therefore, the diffracted light generated at the edge of the transmissive portion is canceled out by the exposure light transmitted through the semi-transmissive portion, allowing the phase-shifting mask to form finer micro-patterns on the wafer surface.

[0007] Existing technical documents

[0008] Patent documents

[0009] (Patent Document 1) Korean Patent Publication No. 10-2007-0060529

[0010] (Patent Document 2) Korean Patent No. 10-1593390 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] The purpose of this embodiment is to provide a blank mask, etc., that can obtain more accurate measurement values ​​when measuring the optical properties and detecting defects of a light-shielding film.

[0013] means for solving problems

[0014] According to one embodiment of this specification, a blank mask includes a light-transmitting substrate and a light-shielding film disposed on the light-transmitting substrate.

[0015] The light-shielding film includes at least one of a transition metal, oxygen, and nitrogen.

[0016] When the optical density of the light-shielding film is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density value is less than or equal to 0.009.

[0017] The value obtained by subtracting the minimum value from the maximum value of the measured optical density is less than 0.03.

[0018] The Rsk value of the surface of the light-shielding film is greater than or equal to -2 and less than or equal to 0.1.

[0019] The measured optical density value is the average of the optical density values ​​measured at a total of 49 specific measurement points on the surface of the light-shielding film.

[0020] The term "ten measurements" refers to the measurement being performed at a total of 49 specific measurement points on the surface of the light-shielding film during each measurement, with the same measurement points being used in all ten measurements.

[0021] When the reflectance of the light-shielding film is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured reflectance value can be less than or equal to 0.032%.

[0022] The value obtained by subtracting the minimum value from the maximum value of the measured reflectance values ​​can be less than or equal to 0.09%.

[0023] For light with a wavelength greater than or equal to 190 nm and less than or equal to 550 nm, the reflectivity of the light-shielding film can be greater than or equal to 15% and less than or equal to 35%.

[0024] The Rku value of the surface of the light-shielding film can be less than or equal to 3.5.

[0025] The Rp value of the surface of the light-shielding film can be less than or equal to 4.7 nm.

[0026] The Rpv value of the surface of the light-shielding film can be less than or equal to 8.5 nm.

[0027] The light-shielding film may include a first light-shielding layer and a second light-shielding layer disposed on the first light-shielding layer.

[0028] The content of transition metal in the second light-shielding layer can be greater than the content of transition metal in the first light-shielding layer.

[0029] The transition metal includes at least one of Cr, Ta, Ti, and Hf.

[0030] According to another embodiment of this specification, a photomask includes a light-transmitting substrate and a light-shielding pattern film disposed on the light-transmitting substrate.

[0031] The light-shielding patterned film includes at least one of a transition metal, oxygen, and nitrogen.

[0032] When the optical density of the upper surface of the light-shielding pattern film is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density value is less than or equal to 0.009.

[0033] The value obtained by subtracting the minimum value from the maximum value of the measured optical density is less than 0.03.

[0034] The Rsk value of the upper surface of the light-shielding pattern film is greater than or equal to -2 and less than or equal to 0.1.

[0035] A method for manufacturing a semiconductor device according to another embodiment of this specification includes: a preparation step of setting up a light source, a photomask, and a semiconductor wafer coated with a resist film; an exposure step of selectively transmitting and emitting light incident from the light source onto the semiconductor wafer through the photomask; and a development step of developing a pattern on the semiconductor wafer.

[0036] The photomask includes a light-transmitting substrate and a light-shielding pattern film disposed on the light-transmitting substrate.

[0037] The light-shielding patterned film includes at least one of a transition metal, oxygen, and nitrogen.

[0038] When the optical density of the upper surface of the light-shielding pattern film is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density value is less than or equal to 0.009.

[0039] The value obtained by subtracting the minimum value from the maximum value of the measured optical density is less than 0.03.

[0040] The Rsk value of the upper surface of the light-shielding pattern film is greater than or equal to -2 and less than or equal to 0.1.

[0041] Invention Effects

[0042] The blank mask and the like in this embodiment can obtain more accurate measurement values ​​when performing optical property measurements and defect detection of the light-shielding film. Attached Figure Description

[0043] Figure 1 This is a conceptual diagram illustrating a blank mask according to one embodiment disclosed in this specification.

[0044] Figure 2 This is a conceptual diagram describing a method for measuring the optical density of a light-shielding film.

[0045] Figure 3 This is a conceptual diagram illustrating a blank mask according to another embodiment disclosed in this specification.

[0046] Figure 4 This is a conceptual diagram illustrating a blank mask according to yet another embodiment disclosed in this specification.

[0047] Figure 5 This is a conceptual diagram illustrating yet another embodiment of a photomask disclosed in this specification.

[0048] Explanation of reference numerals in the attached figures

[0049] 100: Blank Mask

[0050] 10: Transparent substrate

[0051] 20: Blackout film

[0052] 21: First light-shielding layer

[0053] 22: Second light-shielding layer

[0054] 30: Phase-shifting film

[0055] 200: Photomask

[0056] 25: Light-blocking patterned film

[0057] da: Measurement area

[0058] dp: measurement point

[0059] ds: sector Detailed Implementation

[0060] The embodiments will be described in detail below to enable those skilled in the art to readily implement them. However, these embodiments can be implemented in various different forms and are not limited to the embodiments described herein.

[0061] The terms “about” and “substantially” used in this specification are used to mean equal to or close to the range of values ​​when providing the inherent manufacturing and material tolerances in the sense they refer to, in order to prevent unscrupulous infringers from improperly using the disclosures, including precise or absolute values, provided to aid in understanding this embodiment.

[0062] Throughout this specification, the term “combination thereof” as used in the Markush form refers to a mixture or combination of one or more components selected from the group consisting of the components described in the Markush form, and is intended to include one or more components selected from the group consisting of the aforementioned components.

[0063] Throughout this specification, the reference to “A and / or B” means “A, B, or A and B”.

[0064] Throughout this specification, unless otherwise stated, terms such as “first,” “second,” or “A,” “B” are used to distinguish the same terms.

[0065] In this specification, "B is located on A" means that B is directly located on A or that B is located on A and there are other layers between B and A. The interpretation is not limited to B being located at a position that is in contact with the surface of A.

[0066] In this specification, unless otherwise stated, the singular form is to be interpreted as including the meaning of singular or plural as interpreted in the context.

[0067] In this specification, surface profile refers to the contour shape observed on a surface.

[0068] The Rsk value is an evaluation value based on ISO 4287. The Rsk value represents the skewness of the surface profile being measured.

[0069] The Rku value is a value evaluated according to ISO 4287. The Rku value represents the kurtosis of the surface profile being measured.

[0070] A peak is the portion located above the baseline (meaning the average height line in the surface profile) of the light-shielding film surface profile.

[0071] A valley is the portion of the surface contour of a light-shielding film located below the baseline.

[0072] The Rp value is an evaluation value according to ISO 4287. The Rp value is the maximum peak height in the surface profile to be measured.

[0073] The Rv value is an evaluation value according to ISO 4287. The Rv value is the maximum valley depth in the surface profile to be measured.

[0074] The Rpv value is the sum of the Rp and Rv values ​​of the surface to be measured.

[0075] In this specification, standard deviation refers to the sample standard deviation.

[0076] In this specification, a false defect refers to a defect located on the surface of the light-shielding film that does not cause a decrease in the resolution of the blank mask and is therefore not a true defect, but will be detected as a defect when detected by a high-sensitivity defect detection device.

[0077] The increasing integration of semiconductors has created a need for forming finer circuit patterns on semiconductor wafers. As the linewidth of the patterns developed on semiconductor wafers further shrinks, problems related to the decrease in photomask resolution are also increasing.

[0078] In order to accurately develop fine circuit patterns on semiconductor wafers, it may be necessary to control the light-shielding pattern film of the photomask to have the required optical properties, and it may be necessary to precisely pattern the light-shielding pattern film according to a pre-designed pattern shape.

[0079] Before patterning the light-shielding film in the blank mask, an optical property test, such as optical density and reflectivity, can be performed using a spectral ellipsometer. Alternatively, defect detection can be performed after the light-shielding film is formed and after the patterned light-shielding film is formed. During optical property testing, the measured values ​​may vary with the number of measurements, making it difficult to accurately measure the optical density and reflectivity of the light-shielding film. Furthermore, during defect detection, depending on the surface characteristics of the light-shielding film, a large number of false defects or flare phenomena may be detected, potentially making it difficult to detect true defects.

[0080] The inventors of this embodiment confirmed that when the optical density of the light-shielding film is measured multiple times, the standard deviation of the measured value after adjustment is indicated, and that the above-mentioned problems can be solved by using a blank mask or the like, which can be controlled by applying the deflection of the surface of the light-shielding film, thereby completing this embodiment.

[0081] This embodiment will be described in detail below.

[0082] Figure 1 This is a conceptual diagram illustrating a blank mask according to an embodiment disclosed in this specification. Referring to the above... Figure 1 The blank mask described in this embodiment.

[0083] The blank mask 100 includes a light-transmitting substrate 10 and a light-shielding film 20 located on the light-transmitting substrate 10.

[0084] The material of the light-transmitting substrate 10 can be any material that is transparent to exposure light and can be applied to the blank mask 100. Specifically, the light-transmitting substrate 10 has a transmittance of greater than or equal to 85% for exposure light with a wavelength of 193 nm. The transmittance can be greater than or equal to 87%. The transmittance can be less than or equal to 99.99%. As an example, the light-transmitting substrate 10 can be a synthetic quartz substrate. In this case, the light-transmitting substrate 10 can suppress the attenuation of light transmitted through it.

[0085] In addition, the light-transmitting substrate 10 can suppress the occurrence of optical distortion by adjusting surface characteristics such as flatness and roughness.

[0086] The light-shielding film 20 can be located on the top side of the light-transmitting substrate 10.

[0087] The light-blocking film 20 can have the property of blocking at least a portion of the exposure light incident from the bottom side of the light-transmitting substrate 10. Furthermore, when the phase-shifting film 30 (refer to...) Figure 4 When the light-transmitting substrate 10 and the light-shielding film 20 are located 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 shift film 30 and the like according to the pattern shape.

[0088] The light-shielding film 20 includes at least one of a transition metal, oxygen, and nitrogen.

[0089] Optical properties of light-shielding film

[0090] When the optical density of the light-shielding film 20 is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density value is less than or equal to 0.009.

[0091] The value obtained by subtracting the minimum value from the maximum value of the measured optical density is less than 0.03.

[0092] The optical density and reflectivity of the light-shielding film 20 after deposition can be measured using a spectroscopic ellipsometry. However, during the measurement process, when the light-shielding film 20 is measured multiple times using the same method, the deviation in the measured values ​​can be very large. The inventors believe this is because diffuse reflection of the detection light occurs on the surface of the light-shielding film 20, hindering accurate measurement.

[0093] In this embodiment, the light-shielding film 20 is adjusted by applying the standard deviation of the measured value obtained by measuring the optical density multiple times using the same measurement method, thereby making it easy to accurately measure the optical density value of the light-shielding film 20.

[0094] The measurement methods for the standard deviation of the optical density value of the light-blocking film 20 are as follows.

[0095] Figure 2 This is a conceptual diagram illustrating a method for measuring the optical density of a light-shielding film. (Refer to the above.) Figure 2 The blank mask described in this embodiment.

[0096] A measurement area da, 132 mm wide and 132 mm long, is defined at the center of the light-shielding film 20. The measurement area da is divided into six equal parts in both the horizontal and vertical directions, forming a total of 36 sectors ds. A total of 49 vertices in each sector ds are designated as measurement points dp, and the transmittance value of the light-shielding film 20 is measured at these measurement points dp. The optical density is calculated based on the transmittance value using the following formula (Equation 1).

[0097] Form 1:

[0098]

[0099] Calculate the average value of the optical density at each measurement point dp, and use the calculated value as the optical density value of the light-shielding film 20.

[0100] The optical density of the light-blocking film 20 was measured ten times to calculate the standard deviation of the optical density values ​​and the value obtained by subtracting the minimum value from the maximum value. All ten measurements of the optical density of the light-blocking film 20 were performed under the same measurement conditions at the same measurement point dp.

[0101] Optical density can be measured using a spectroradiometer. The wavelength of the detected light is 193 nm. As an example, a NanoView MG-Pro spectroradiometer can be used.

[0102] When the optical density of the light-shielding film 20 is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density value can be less than or equal to 0.009. The standard deviation can be less than or equal to 0.006. The standard deviation can be less than or equal to 0.0055. The standard deviation can be greater than or equal to 0.

[0103] The value obtained by subtracting the minimum value from the maximum measured optical density value can be less than 0.03. The value obtained by subtracting the minimum value from the maximum value can be less than or equal to 0.025. The value obtained by subtracting the minimum value from the maximum value can be less than or equal to 0.02. The value obtained by subtracting the minimum value from the maximum value can be greater than or equal to 0.

[0104] In this case, the optical density of the light-shielding film 20 can be measured more accurately.

[0105] The light-blocking film can have an optical density value greater than or equal to 1.5 and less than or equal to 3 for light with a wavelength of 193 nm. The light-blocking film can have an optical density value greater than or equal to 1.7 and less than or equal to 2.8 for light with a wavelength of 193 nm. The light-blocking film can have an optical density value greater than or equal to 1.8 and less than or equal to 2.5 for light with a wavelength of 193 nm. In this case, when the light-blocking film and the phase-shifting film form a laminated structure, they can effectively block exposure light.

[0106] The light-shielding film 20 can have a transmittance of 1% or more for light with a wavelength of 193 nm. Alternatively, the light-shielding film 20 can have a transmittance of 1.3% or more for light with a wavelength of 193 nm. Or, the light-shielding film 20 can have a transmittance of 1.4% or less for light with a wavelength of 193 nm. In this case, the light-shielding film 20 can be laminated onto the phase-shift film to effectively block exposure light.

[0107] When the transmittance of the light-shielding film 20 is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured transmittance values ​​can be less than or equal to 0.0018%. The value obtained by subtracting the minimum value from the maximum value of the measured transmittance values ​​can be less than or equal to 0.0055%.

[0108] The method for measuring the standard deviation and the value obtained by subtracting the minimum value from the maximum value of the transmittance is the same as the method described above for measuring the standard deviation and the value obtained by subtracting the minimum value from the maximum value of the optical density.

[0109] When the transmittance of the light-shielding film 20 is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured transmittance value can be less than or equal to 0.0018%. The standard deviation can be less than or equal to 0.0015%. The standard deviation can be less than or equal to 0.001%. The standard deviation can be greater than or equal to 0%.

[0110] When the transmittance of the light-shielding film 20 is measured ten times using light with a wavelength of 193 nm, the value obtained by subtracting the minimum value from the maximum value can be less than or equal to 0.0055%. The value obtained by subtracting the minimum value from the maximum value can be less than or equal to 0.0045%. The value obtained by subtracting the minimum value from the maximum value can be less than or equal to 0%.

[0111] In this case, the transmittance can be easily measured from the light-shielding film 20 using a spectral ellipsometry.

[0112] When the reflectance of the light-shielding film 20 is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured reflectance value is less than or equal to 0.032%.

[0113] The value obtained by subtracting the minimum value from the maximum value of the measured reflectance is less than or equal to 0.09%.

[0114] The method used to measure reflectance is the same as the method described above for measuring optical density.

[0115] When the reflectance of the light-shielding film 20 is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured reflectance value can be less than or equal to 0.032%. The standard deviation can be less than or equal to 0.03%. The standard deviation can be less than or equal to 0.028%. The standard deviation can be greater than or equal to 0%.

[0116] The value obtained by subtracting the minimum value from the maximum value of the measured reflectance values ​​can be less than or equal to 0.09%. The value obtained by subtracting the minimum value from the maximum value can be less than or equal to 0.0855%. The value obtained by subtracting the minimum value from the maximum value can be less than or equal to 0.083%. The value obtained by subtracting the minimum value from the maximum value can be greater than or equal to 0%.

[0117] In this case, a more accurate reflectance value can be measured from the surface of the light-shielding film 20.

[0118] The reflectivity of the light-shielding film 20 for light with a wavelength greater than or equal to 190 nm and less than or equal to 550 nm can be greater than or equal to 15% and less than or equal to 35%.

[0119] During defect detection on the surface of the light-shielding film 20, detection light is incident on the surface of the light-shielding film 20 and reflected light is formed on the surface of the light-shielding film 20. The defect detector can analyze the reflected light to determine whether a defect exists. In this embodiment, the reflectivity of the surface of the light-shielding film 20 can be controlled within a preset range within the detection light wavelength range of the defect detector. Therefore, it is possible to suppress the decrease in accuracy of the defect detector due to uncontrolled light intensity during defect detection.

[0120] The reflectance of the light-shielding film 20 was measured using a spectroscopic ellipsometry. As an example, the reflectance of the light-shielding film 20 can be measured using a NanoView MG-Pro instrument.

[0121] The reflectivity of the light-shielding film 20 for light with a wavelength greater than or equal to 190 nm and less than or equal to 550 nm can be greater than or equal to 15% and less than or equal to 35%. The reflectivity can be greater than or equal to 17% and less than or equal to 30%. The reflectivity can be greater than or equal to 20% and less than or equal to 28%. In this case, the accuracy of surface defect detection of the light-shielding film 20 can be further improved.

[0122] Relevant characteristics of surface roughness of light-shielding film

[0123] The Rsk value of the surface of the light-shielding film 20 can be greater than or equal to -2 and less than or equal to 0.1.

[0124] Depending on the surface roughness characteristics of the light-shielding film 20, the measured values ​​of its optical properties may vary with the number of measurements. During the reflection and transmission of the detection light on the surface of the light-shielding film 20, peaks distributed on the surface of the film 20 may cause diffuse reflection of the detection light. This may affect the accuracy of the measured optical properties.

[0125] To suppress diffuse reflection of the detection light, one approach is to simply reduce the surface roughness of the light-shielding film 20. However, in this case, excessively strong reflected light may incident on the detector lens during the detection of defects on the surface of the light-shielding film 20, causing glare. Glare can distort the measured image of the light-shielding film surface, making it difficult to detect actual defects in the light-shielding film 20.

[0126] This embodiment allows control over the composition, layer structure, and surface treatment process conditions of the light-shielding film 20. Simultaneously, the surface profile of the light-shielding film 20, particularly its skewness characteristics, can be controlled within a preset range in this embodiment. This allows for control of the reflected light path, facilitating more accurate measurements when determining optical properties. Furthermore, during defect detection, image distortion on the surface of the light-shielding film can be effectively suppressed.

[0127] The method for measuring the Rsk value of the surface of the light-shielding film 20 is as follows.

[0128] The Rsk value is measured in a 1 μm wide and 1 μm long region located at the center (central part) of the surface of the light-shielding film 20. A two-dimensional roughness measuring instrument is used in this region with a scan rate set to 0.5 Hz to measure the Rsk value in non-contact mode. As an example, the Rsk value can be measured using a Park System XE-150 probe, which employs a Park System Cantilever PPP-NCHR probe.

[0129] The Rsk value of the surface of the light-shielding film 20 can be greater than or equal to -2 and less than or equal to 0.1. The Rsk value can be greater than or equal to -1. The Rsk value can be greater than or equal to -0.9. The Rsk value can be greater than or equal to -0.88. The Rsk value can be greater than or equal to -0.8. The Rsk value can be greater than or equal to -0.7. The Rsk value can be less than or equal to 0. The Rsk value can be less than or equal to -0.15. The Rsk value can be less than or equal to -0.2. In this case, the degree of diffuse reflection of detection light on the surface of the light-shielding film 20 can be effectively reduced.

[0130] The Rku value of the surface of the light-shielding film 20 can be less than or equal to 3.5.

[0131] This embodiment allows control over the kurtosis of peaks distributed on the surface of the light-shielding film 20. In this case, during the detection of optical properties, deviation of the detection light reflected from the surface of the light-shielding film from the target optical path can be suppressed. Furthermore, by suppressing excessively high reflectivity of the surface of the light-shielding film 20, the accuracy of defect detection can be further improved.

[0132] The method for measuring the Rku value on the surface of the light-shielding film 20 is the same as the method described above for measuring the Rsk value.

[0133] The Rku value of the surface of the light-shielding film 20 can be less than or equal to 3.5. The Rku value can be less than or equal to 3.2. The Rku value can be less than or equal to 3. The Rku value can be greater than or equal to 1. The Rku value can be greater than or equal to 2. In this case, it can help suppress diffuse reflection on the surface of the light-shielding film 20 and help the light-shielding film present a reflectivity suitable for defect detection.

[0134] This embodiment allows control over the maximum peak height or maximum valley depth on the surface of the light-shielding film 20. Therefore, during defect detection, the detection light reflected from the surface of the light-shielding film 20 can have sufficient intensity to detect defects, thereby significantly reducing the detection frequency of false defects. Furthermore, when measuring optical characteristic values, measurement deviations can be reduced.

[0135] The method for measuring the Rp and Rv values ​​of the surface of the light-shielding film 20 is the same as the method described above for measuring the Rsk value. The Rpv value is obtained by adding the Rp and Rv values.

[0136] The Rp value on the surface of the light-shielding film 20 can be less than or equal to 4.7 nm. The Rp value can be less than or equal to 4.65 nm. The Rp value can be less than or equal to 4.5 nm. The Rp value can be greater than or equal to 1 nm.

[0137] The Rv value of the surface of the light-shielding film 20 can be less than or equal to 3.9 nm. The Rv value can be less than or equal to 3.6 nm. The Rv value can be less than or equal to 3.5 nm. The Rv value can be greater than or equal to 1 nm.

[0138] The Rpv value on the surface of the light-shielding film 20 can be less than or equal to 8.5 nm. The Rpv value can be less than or equal to 8.4 nm. The Rpv value can be less than or equal to 8.3 nm. The Rpv value can be less than or equal to 8 nm. The Rpv value can be less than or equal to 7.9 nm. The Rpv value can be greater than or equal to 1 nm.

[0139] In this case, the accuracy of defect detection and optical property measurement on the surface of the light-shielding film 20 can be improved.

[0140] Layer structure and composition of light-shielding film

[0141] Figure 3 This is a conceptual diagram illustrating a blank mask according to another embodiment of this specification. Referring to the above... Figure 3 This implementation method is described.

[0142] 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.

[0143] The second light-shielding layer 22 may include at least one of a transition metal, oxygen, and nitrogen. The second light-shielding layer 22 may contain 35 at% or more of a transition metal. The second light-shielding layer 22 may contain 40 at% or more of a transition metal. The second light-shielding layer 22 may contain 45 at% or more of a transition metal. The second light-shielding layer 22 may contain 50 at% or more of a transition metal. The second light-shielding layer 22 may contain less than 75 at% of a transition metal. The second light-shielding layer 22 may contain less than 70 at% of a transition metal. The second light-shielding layer 22 may contain less than 65 at% of a transition metal. The second light-shielding layer 22 may contain less than 60 at% of a transition metal.

[0144] The content of the element corresponding to oxygen or nitrogen in the second light-shielding layer 22 can be 15 at% or more. The content can be 20 at% or more. The content can be 25 at% or more. The content can be 55 at% or less. The content can be 50 at% or less. The content can be 45 at% or less.

[0145] The second light-shielding layer 22 may contain more than 5 at% oxygen. The second light-shielding layer 22 may contain more than 10 at% oxygen. The second light-shielding layer 22 may contain less than 25 at% oxygen. The second light-shielding layer 22 may contain less than 20 at% oxygen.

[0146] The second light-shielding layer 22 may contain 10 at% or more nitrogen. The second light-shielding layer 22 may contain 15 at% or more nitrogen. The second light-shielding layer 22 may contain less than 30 at% nitrogen. The second light-shielding layer 22 may contain less than 25 at% nitrogen.

[0147] The second light-shielding layer 22 may contain more than 1 at% carbon. The second light-shielding layer 22 may contain more than 3 at% carbon. The second light-shielding layer 22 may contain less than 10 at% carbon. The second light-shielding layer 22 may contain less than 8 at% carbon.

[0148] In this case, the light-blocking film 20 can be stacked together with the phase-shifting film 30 to help to adequately block the exposure light.

[0149] The first light-shielding layer 21 may include a transition metal, oxygen, and nitrogen. The first light-shielding layer 21 may contain 20 at% or more of a transition metal. The first light-shielding layer 21 may contain 25 at% or more of a transition metal. The first light-shielding layer 21 may contain 30 at% or more of a transition metal. The first light-shielding layer 21 may contain less than 55 at% of a transition metal. The first light-shielding layer 21 may contain less than 50 at% of a transition metal. The first light-shielding layer 21 may contain less than 45 at% of a transition metal.

[0150] The sum of the oxygen and nitrogen content of the first light-shielding layer 21 can be 22 at% or more. The sum of the oxygen and nitrogen content of the first light-shielding layer 21 can be 30 at% or more. The sum of the oxygen and nitrogen content of the first light-shielding layer 21 can be 40 at% or more. The sum of the oxygen and nitrogen content of the first light-shielding layer 21 can be 70 at% or less. The sum of the oxygen and nitrogen content of the first light-shielding layer 21 can be 60 at% or less. The sum of the oxygen and nitrogen content of the first light-shielding layer 21 can be 50 at% or less.

[0151] The first light-shielding layer 21 may contain more than 20 at% oxygen. The first light-shielding layer 21 may contain more than 25 at% oxygen. The first light-shielding layer 21 may contain more than 30 at% oxygen. The first light-shielding layer 21 may contain less than 50 at% oxygen. The first light-shielding layer 21 may contain less than 45 at% oxygen. The first light-shielding layer 21 may contain less than 40 at% oxygen.

[0152] The first light-shielding layer 21 may contain 2 at% or more nitrogen. The first light-shielding layer 21 may contain 5 at% or more nitrogen. The first light-shielding layer 21 may contain less than 20 at% nitrogen. The first light-shielding layer 21 may contain less than 15 at% nitrogen.

[0153] The first light-shielding layer 21 may contain 5 at% or more carbon. The first light-shielding layer 21 may contain 10 at% or more carbon. The first light-shielding layer 21 may contain less than 25 at% carbon. The first light-shielding layer 21 may contain less than 20 at% carbon.

[0154] In this case, the first light-shielding layer 21 can help the light-shielding film 20 have excellent light-absorbing properties.

[0155] The transition metal may include at least one of Cr, Ta, Ti, and Hf. The transition metal may be Cr.

[0156] The thickness of the first light-shielding layer 21 can be to The thickness of the first light-shielding layer 21 can be to The thickness of the first light-shielding layer 21 can be to In this case, the first light-blocking layer 21 can help the light-blocking film 20 effectively block the exposure light.

[0157] The thickness of the second light-shielding layer 22 can be to The thickness of the second light-shielding layer 22 can be to The thickness of the second light-shielding layer 22 can be to In this case, the second light-shielding layer 22 can improve the light-shielding properties of the light-shielding film 20 and can help to more accurately control the side surface profile of the light-shielding pattern film formed when the light-shielding film 20 is patterned.

[0158] The thickness ratio of the second light-shielding layer 22 to the thickness of the first light-shielding layer 21 can be 0.05 to 0.3. The thickness ratio can be 0.07 to 0.25. The thickness ratio can be 0.1 to 0.2. In this case, the light-shielding film 20 has sufficient light-absorbing properties, and the light-shielding pattern film formed during the patterning of the light-shielding film 20 can form a nearly vertical side surface profile.

[0159] The content of transition metal in the second light-shielding layer 22 can be greater than the content of transition metal in the first light-shielding layer 21.

[0160] The second light-shielding layer 22 can have a higher transition metal content than the first light-shielding layer 21 to precisely control the side surface profile of the patterned light-shielding film formed during the patterning process of the light-shielding film 20 and ensure reflectivity suitable for defect detection. However, in this case, with the heat treatment of the light-shielding film 20, the recovery, recrystallization, and grain growth of the transition metal may occur in the second light-shielding layer 22. When grain growth is not controlled in the second light-shielding layer 22 with a high transition metal content, the surface of the light-shielding film 20 may form a deformed profile compared to before heat treatment due to the overgrown transition metal particles. This may cause changes in the roughness characteristics of the light-shielding film 20 and may affect the accuracy of optical property measurements and defect detection of the light-shielding film 20.

[0161] This embodiment allows for the control of the transition metal content of the second light-shielding layer 22 compared to the first light-shielding layer 21, while simultaneously controlling the process conditions such as the roughness characteristics, heat treatment, cooling treatment, and surface treatment of the light-shielding film 20. Consequently, the light-shielding film 20 can possess the desired optical and etching properties, while also enabling more accurate optical property measurements and defect detection results to be obtained from its surface.

[0162] Other films

[0163] Figure 4 This is a conceptual diagram illustrating a blank mask according to yet another embodiment of this specification. Referring to the above... Figure 4 The blank mask described in this embodiment.

[0164] According to another embodiment of this specification, a blank mask 100 includes a light-transmitting substrate 10, a phase-shifting film 30 disposed on the light-transmitting substrate 10, and a light-shielding film 20 disposed on the phase-shifting film 30.

[0165] The phase-shifting film 30 comprises a transition metal and silicon.

[0166] The description of the light-shielding film 20 is the same as the foregoing content, and the repeated description is omitted here.

[0167] The phase shift film 30 can be located between the light-transmitting substrate 10 and the light-shielding film 20. The phase shift film 30 is a thin film used to attenuate the intensity of the exposed light transmitted through the phase shift film 30 and substantially suppress the diffraction light generated at the edge of the pattern by adjusting the phase difference.

[0168] The phase shift film 30 can have a phase difference of 170° to 190° with light of wavelength 193 nm. The phase shift film 30 can also have a phase difference of 175° to 185° with light of wavelength 193 nm. The transmittance of the phase shift film 30 with light of wavelength 193 nm can be 3% to 10%. The transmittance of the phase shift film 30 with light of wavelength 193 nm can be 4% to 8%. In this case, the resolution of the photomask including the phase shift film 30 can be improved.

[0169] The phase-shifting film 30 may include a transition metal and silicon. The phase-shifting film 30 may include a transition metal, silicon, oxygen, and nitrogen. The transition metal may be molybdenum.

[0170] The descriptions of the physical properties and composition of the light-transmitting substrate 10 and the light-shielding film 20 are repeated from the foregoing, and the repeated descriptions are omitted here.

[0171] A hard mask (not shown) can be placed on the light-shielding film 20. When etching the pattern of the light-shielding film 20, the hard mask can function as an etching mask. The hard mask may include silicon, oxygen, and nitrogen.

[0172] Photomask

[0173] Figure 5 This is a conceptual diagram illustrating a photomask according to yet another embodiment of this specification. Referring to the above... Figure 5 The photomask of this embodiment is described.

[0174] According to another embodiment of this specification, a photomask 200 includes a light-transmitting substrate 10 and a light-shielding pattern film 25 disposed on the light-transmitting substrate 10.

[0175] The light-shielding patterned film 25 includes at least one of a transition metal, oxygen, and nitrogen.

[0176] When the optical density of the upper surface of the light-shielding pattern film 25 is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density value is less than or equal to 0.009.

[0177] The value obtained by subtracting the minimum value from the maximum value of the measured optical density is less than 0.03.

[0178] The Rsk value of the upper surface of the light-blocking pattern film 25 is greater than or equal to -2 and less than or equal to 0.1.

[0179] A light-shielding patterned film 25 can be formed by patterning the light-shielding film 20 of the aforementioned blank mask 100.

[0180] The method for measuring the optical density of the light-blocking pattern film 25 is the same as the method for measuring the optical density of the light-blocking film 20 described above. However, when the measurement point is not located on the upper surface of the light-blocking pattern film 25, the measurement point should be reset on the upper surface of the light-blocking pattern film 25 near the measurement point before measuring the optical density.

[0181] The method for measuring the Rsk value on the upper surface of the light-shielding pattern film 25 is the same as the method described above for measuring the Rsk value on the surface of the light-shielding film 20. However, when the upper surface of the light-shielding pattern film 25 does not have a 1 μm wide and 1 μm long region located in the center (central part) of the surface of the photomask 200, the measurement is performed on the upper surface of the light-shielding pattern film 25 located near said region.

[0182] The description of the physical properties, composition and structure of the light-shielding pattern film 25 is repeated with the description of the light-shielding layer 20 of the blank mask 100, and the repeated description is omitted here.

[0183] Manufacturing method of light-blocking film

[0184] A method for manufacturing a blank mask according to one embodiment of this specification may include: a preparation step of setting a light-transmitting substrate and a sputtering target in a sputtering chamber.

[0185] A method for manufacturing a blank mask according to one embodiment of this specification may include: a film-forming step of injecting an atmospheric gas into a sputtering chamber and applying power to a sputtering target to form a light-shielding film on a light-transmitting substrate.

[0186] The film formation steps may include: a first light-shielding layer film formation process, forming a first light-shielding layer on a light-transmitting substrate; and a second light-shielding layer film formation process, forming a second light-shielding layer on the first light-shielding layer.

[0187] A method for manufacturing a blank mask according to one embodiment of this specification may include a heat treatment step, wherein the heat treatment is performed for a period of 5 minutes to 30 minutes in an atmosphere at a temperature greater than or equal to 150°C and less than or equal to 300°C.

[0188] A method for manufacturing a blank mask according to one embodiment of this specification may include a cooling step, cooling the light-shielding film after the heat treatment step.

[0189] A method for manufacturing a blank mask according to one embodiment of this specification may include a stabilization step, wherein the blank mask after the cooling step is stabilized in an atmosphere of 10°C or higher and 60°C or lower.

[0190] A method for manufacturing a blank mask according to one embodiment of this specification may include a surface treatment step, which involves surface treating the light-shielding film of the blank mask after a stabilization step.

[0191] The surface treatment steps may include a surface oxidation process in which an oxidant solution is applied to the surface of the light-shielding film.

[0192] The surface treatment steps may include a rinsing process to wash the surface of the light-shielding film.

[0193] In the preparation step, when forming the light-shielding film, the composition of the light-shielding film can be considered when selecting the target material. As a sputtering target, a target containing a transition metal can be used. Two or more targets, including one containing a transition metal, can be used. The target containing the transition metal can contain 90 at% or more of the transition metal. The target containing the transition metal can contain 95 at% or more of the transition metal. The target containing the transition metal can contain 99 at% of the transition metal.

[0194] Transition metals may include at least one of Cr, Ta, Ti, and Hf. Transition metals may include Cr. Transition metals may be Cr.

[0195] The description of the light-transmitting substrate disposed in the sputtering chamber is repeated above, and the repeated description is omitted here.

[0196] In the preparation step, a magnet can be placed inside the sputtering chamber. The magnet can be placed on a surface opposite to one of the sputtering surfaces of the sputtering target.

[0197] In the film formation step of the light-shielding film, different film formation process conditions can be applied when forming films for each layer of the light-shielding film. In particular, various process conditions such as the atmospheric gas composition, the power applied to the sputtering target, and the film formation time can be applied differently for each layer of the light-shielding film, taking into account the surface roughness characteristics, matting characteristics, and etching characteristics of the light-shielding film.

[0198] Atmosphere gases can include inert gases, reactive gases, and sputtering gases. Inert gases are gases that do not contain the elements that constitute the thin film. Reactive gases are gases that contain the elements that constitute the thin film. Sputtering gases are gases that are ionized in a plasma atmosphere and collide with the target material.

[0199] Inert gases can include helium.

[0200] The reactant gas may include a gas containing nitrogen. The nitrogen-containing gas may be, for example, N2, NO, NO2, N2O, N2O3, N2O4, N2O5, etc. The reactant gas may also include a gas containing oxygen. The oxygen-containing gas may be, for example, O2, CO2, etc. The reactant gas may include both nitrogen-containing and oxygen-containing gases. The reactant gas may also include a gas containing both nitrogen and oxygen. The gas containing both nitrogen and oxygen may be, for example, NO, NO2, N2O, N2O3, N2O4, N2O5, etc.

[0201] The sputtering gas can be Ar gas.

[0202] The power supply used to apply power to the sputtering target can be a DC power supply or an RF power supply.

[0203] During the formation of the first light-shielding layer, the power applied to the sputtering target can be greater than or equal to 1.5 kW and less than or equal to 2.5 kW. During the formation of the first light-shielding layer, the power applied to the sputtering target can be greater than or equal to 1.6 kW and less than or equal to 2 kW.

[0204] During the formation of the first light-shielding layer, the ratio of the flow rate of the reactant gas to the flow rate of the inert gas in the atmosphere can be greater than or equal to 1.5 and less than or equal to 3. The flow rate ratio can be greater than or equal to 1.8 and less than or equal to 2.7. The flow rate ratio can be greater than or equal to 2 and less than or equal to 2.5.

[0205] The ratio of oxygen to nitrogen in the reactant gas can be greater than or equal to 1.5 and less than or equal to 4. The ratio of oxygen to nitrogen in the reactant gas can be greater than or equal to 2 and less than or equal to 3. The ratio of oxygen to nitrogen in the reactant gas can be greater than or equal to 2.2 and less than or equal to 2.7.

[0206] In this case, the first light-shielding layer can help the light-shielding film have sufficient light-absorbing properties. By controlling the etching characteristics of the first light-shielding layer, it is possible to help the patterned side surface contour of the light-shielding film to have a shape that is nearly perpendicular to the light-transmitting substrate after patterning.

[0207] The film formation time of the first light-shielding layer can be greater than or equal to 200 seconds and less than or equal to 300 seconds. Alternatively, the film formation time of the first light-shielding layer can be greater than or equal to 210 seconds and less than or equal to 240 seconds. In this case, the first light-shielding layer helps the light-shielding film to have sufficient light-absorbing properties.

[0208] After the first light-shielding layer is formed, the supply of power and atmosphere gas to the sputtering chamber can be stopped for a period of 5 seconds or more and 10 seconds or less, and the power and atmosphere gas can be supplied again during the second light-shielding layer formation process.

[0209] During the formation of the second light-shielding layer, the power applied to the sputtering target can be greater than or equal to 1 kW and less than or equal to 2 kW. During the formation of the second light-shielding layer, the power applied to the sputtering target can be greater than or equal to 1.2 kW and less than or equal to 1.7 kW.

[0210] During the formation of the second light-shielding layer, the ratio of the flow rate of the reactant gas to the flow rate of the inert gas in the atmosphere can be greater than or equal to 0.3 and less than or equal to 0.8. The flow rate ratio can be greater than or equal to 0.4 and less than or equal to 0.6.

[0211] During the formation of the second light-shielding layer, the ratio of oxygen to nitrogen content in the reactant gas can be less than or equal to 0.3. The ratio of oxygen to nitrogen content in the reactant gas can be less than or equal to 0.1. The ratio of oxygen to nitrogen content in the reactant gas can be greater than or equal to 0.001.

[0212] In this case, it helps to control the surface roughness characteristics of the light-shielding film within the range expected in this embodiment, and helps to give the light-shielding film stable light-shielding characteristics.

[0213] The deposition time of the second light-shielding layer can be greater than or equal to 10 seconds and less than or equal to 30 seconds. Alternatively, the deposition time of the second light-shielding layer can be greater than or equal to 15 seconds and less than or equal to 25 seconds. In this case, the second light-shielding layer can be included in the light-shielding film to help suppress the transmission of exposed light.

[0214] In the heat treatment step, the light-shielding film that has completed the film formation step can be heat-treated. Specifically, the substrate on which the light-shielding film has been formed can be placed in a heat treatment chamber, and then heat treatment can be performed.

[0215] Heat treatment of the light-shielding film can remove the stress formed within it and further increase its density. During heat treatment, the transition metals within the film are recovered and recrystallized, effectively removing the stress. However, when process conditions such as temperature and time are not controlled during the heat treatment process, grain growth can occur. Because the transition metal grain size is uncontrolled, the surface profile of the film is significantly deformed compared to before heat treatment. This can affect the surface roughness characteristics of the film and may cause problems in the optical properties and defect detection processes.

[0216] This embodiment can control the heat treatment time and temperature in the heat treatment step, and can control the cooling rate, cooling time, and atmospheric gas during cooling in the cooling step, which will be described in detail later. This allows the internal stress formed on the light-shielding film to be effectively removed, while also giving the surface of the light-shielding film the roughness characteristics preset in this embodiment. This also helps to obtain accurate optical property measurements and defect detection results from the light-shielding film.

[0217] The heat treatment step can be carried out at temperatures ranging from 160°C to 300°C. The heat treatment step can also be carried out at temperatures ranging from 180°C to 280°C.

[0218] The heat treatment process can last from 5 to 30 minutes. Alternatively, it can last from 10 to 20 minutes.

[0219] In this case, the internal stress formed in the light-shielding film can be effectively removed, and it can help suppress the excessive growth of transition metal particles caused by heat treatment.

[0220] In the cooling step, the light-shielding film that has undergone heat treatment can be cooled. A cooling plate adjusted to a preset cooling temperature according to this embodiment can be placed on the substrate side of the blank mask that has undergone heat treatment, thereby cooling the blank mask. In the cooling step, the cooling rate of the blank mask can be controlled by adjusting the spacing between the blank mask and the cooling plate, introducing process conditions such as atmospheric gas, etc.

[0221] A cooling step can be performed on the blank mask within 2 minutes after the heat treatment step is completed. In this case, the growth of transition metal particles due to residual heat inside the light-shielding film can be effectively suppressed.

[0222] Fins of adjusted length are installed at each corner of the cooling plate, and a blank mask is placed on the fins so that the substrate faces the cooling plate, thereby controlling the cooling rate of the blank mask.

[0223] In addition to using a cooling plate, an inert gas can be injected into the space where the cooling step is performed to cool the blank mask. In this case, the residual heat on the light-shielding film side of the blank mask, where the cooling plate has relatively poor cooling efficiency, can be removed more effectively.

[0224] As an example, the inert gas could be helium.

[0225] In the cooling step, the cooling temperature applied to the cooling plate can be from 10°C to 30°C. The cooling temperature can also be from 15°C to 25°C.

[0226] During the cooling step, the distance between the blank mask and the cooling plate can be from 0.01 mm to 30 mm. The distance can also be from 0.05 mm to 5 mm. Furthermore, the distance can be from 0.1 mm to 2 mm.

[0227] In the cooling step, the cooling rate of the blank mask can be from 30°C / min to 80°C / min. The cooling rate can be from 35°C / min to 75°C / min. The cooling rate can be from 40°C / min to 70°C / min.

[0228] In this case, the grain growth of transition metals caused by residual heat in the heat-treated light-shielding film can be suppressed, thereby helping the surface of the light-shielding film to have surface roughness characteristics within the range preset in this embodiment.

[0229] The stabilization step stabilizes the blank mask after the cooling step. This prevents damage to the blank mask caused by rapid temperature changes.

[0230] There are several methods for stabilizing a blank mask after a cooling step. As an example, the blank mask after the cooling step can be separated from the cooling plate and then placed in an atmosphere at room temperature for a predetermined time. As another example, the blank mask after the cooling step can be separated from the cooling plate and then stabilized in an atmosphere at ≥15°C and ≤30°C for ≥30 minutes and ≤200 minutes. In this case, the blank mask can be rotated at a speed of ≥20 rpm and ≤50 rpm. As yet another example, a gas that does not react with the blank mask can be injected into the blank mask after the cooling step at a flow rate of ≥5 L / min and ≤10 L / min for a period of ≥1 minute and ≤5 minutes. In this case, the gas that does not react with the blank mask can have a temperature of ≥20°C and ≤40°C.

[0231] In the surface treatment step, the light-shielding film can be surface-treated by spraying an oxidizing agent solution onto its surface. The oxidizing agent solution is a reactive solution sufficient to oxidize metal films, including the light-shielding film. When the oxidizing agent solution is sprayed onto the surface of the light-shielding film, it reacts with the surface, thus contributing to the surface roughness characteristics desired in this embodiment. In particular, by controlling the composition, flow rate, and spraying method of the oxidizing agent solution, the shape, size, and distribution of peaks on the surface of the light-shielding film can be adjusted within a range preset in this embodiment.

[0232] The surface treatment steps will be described in detail below.

[0233] The surface treatment steps may include a first rinsing process, a surface oxidation process, and a second rinsing process.

[0234] In the surface treatment step, before the surface oxidation process, the surface of the light-shielding film can be subjected to a first rinsing process. Specifically, during the first rinsing process, carbonated water can be sprayed at a flow rate of ≥1000 ml / min and ≤1800 ml / min while the blank mask is rotated at a low speed. This effectively removes particles adsorbed on the surface of the light-shielding film.

[0235] During the surface oxidation process, the oxidant solution can be sprayed onto the surface of the light-shielding film.

[0236] The oxidizing agent solution is not limited, as long as it has the ability to oxidize the metal film. As an example, at least one of hydrogen water and SC-1 solution can be used as the oxidizing agent solution.

[0237] When SC-1 solution is used as an oxidizing agent solution, the ammonia (NH4OH) content in the SC-1 solution can be greater than or equal to 0.02% by volume. The ammonia content can be greater than or equal to 0.05% by volume. The ammonia content can be greater than or equal to 0.1% by volume. The ammonia content can be less than 2% by volume.

[0238] When SC-1 solution is used as an oxidizing agent solution, the hydrogen peroxide (H2O2) content in the SC-1 solution can be less than or equal to 1% by volume. The hydrogen peroxide content can be less than or equal to 0.5% by volume. The hydrogen peroxide content can be less than or equal to 0.1% by volume. The hydrogen peroxide content can be greater than or equal to 0.01% by volume. The hydrogen peroxide content can be greater than or equal to 0.05% by volume.

[0239] The conductivity of the SC-1 solution can be greater than or equal to 1000 μS / cm. The conductivity of the SC-1 solution can be greater than or equal to 1500 μS / cm. The conductivity of the SC-1 solution can be less than or equal to 3000 μS / cm. The conductivity of the SC-1 solution can be greater than or equal to 2500 μS / cm.

[0240] In this case, by controlling the deflection and shape of the light-shielding film surface, the diffuse reflection of the detection light during the measurement of optical properties can be effectively suppressed.

[0241] The oxidizing solution can be sprayed at a total flow rate of ≥500 mL / min and ≤4000 mL / min. The oxidizing solution can be sprayed at a total flow rate of ≥700 mL / min and ≤3000 mL / min. The oxidizing solution can be sprayed at a total flow rate of ≥1000 mL / min and ≤2000 mL / min.

[0242] When using two or more different solutions as oxidizing agents, each solution can be sprayed simultaneously. Alternatively, when using two or more different solutions as oxidizing agents, each solution can be sprayed sequentially.

[0243] The spraying time of the oxidizing solution can be greater than or equal to 100 seconds and less than or equal to 2000 seconds. The spraying time of the oxidizing solution can be greater than or equal to 200 seconds and less than or equal to 1500 seconds. The spraying time of the oxidizing solution can be greater than or equal to 300 seconds and less than or equal to 1000 seconds. The spraying time of the oxidizing solution can be greater than or equal to 400 seconds and less than or equal to 700 seconds.

[0244] In this case, the surface roughness of the light-shielding film can be effectively controlled.

[0245] One solution or two or more solutions can be used as the oxidizing agent. When using two or more solutions as the oxidizing agent, each solution can be sprayed onto the surface of the light-shielding film using separate nozzles.

[0246] When using two or more solutions as oxidizing agents, the spraying time for each solution can be the same. Alternatively, the spraying time for each solution can be different.

[0247] In order to spray the oxidant solution at a uniform flow rate throughout the entire area of ​​the light-shielding film, the oxidant solution can be sprayed while moving the position of the nozzle within the area of ​​the light-shielding film during the spraying process.

[0248] After the surface oxidation process is completed, a second rinsing process can be performed. Specifically, during the second rinsing process, carbonated water can be sprayed at a flow rate of ≥1000 mL / min and ≤1800 mL / min while the blank mask is rotated at a low speed. This effectively removes the oxidant solution remaining on the surface of the light-shielding film.

[0249] Semiconductor device manufacturing method

[0250] A method for manufacturing a semiconductor device according to another embodiment of this specification includes: a preparation step of setting up a light source, a photomask, and a semiconductor wafer coated with a resist film; an exposure step of selectively transmitting and emitting light incident from the light source onto the semiconductor wafer through the photomask; and a development step of developing a pattern on the semiconductor wafer.

[0251] The photomask includes a light-transmitting substrate and a light-blocking pattern film disposed on the light-transmitting substrate.

[0252] The light-shielding patterned film includes at least one of a transition metal, oxygen, and nitrogen.

[0253] When the optical density of the upper surface of the light-shielding pattern film is measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density value is less than or equal to 0.009.

[0254] The value obtained by subtracting the minimum value from the maximum value of the measured optical density is less than 0.03.

[0255] The Rsk value of the upper surface of the light-blocking patterned film is greater than or equal to -2 and less than or equal to 0.1.

[0256] In the preparation step, the light source is a device capable of generating short-wavelength exposure light. The exposure light can be light with a wavelength of 200 nm or less. Alternatively, it can be ArF light with a wavelength of 193 nm.

[0257] A lens can also be placed between the photomask and the semiconductor wafer. The lens has the function of reducing the shape of the circuit pattern on the photomask and transferring it onto the semiconductor wafer. The lens is not limited, as long as it can be widely used in ArF semiconductor wafer exposure processes. As an example, the lens could be made of calcium fluoride (CaF2).

[0258] In the exposure step, exposure light can be selectively transmitted onto the semiconductor wafer through a photomask. In this case, chemical modification can occur on the portion of the resist film where the exposure light has been incident.

[0259] In the developing step, a developing solution can be used to treat the semiconductor wafer after the exposure step to develop a pattern on the semiconductor wafer. When the coated resist film is a positive resist, the portions of the resist film exposed to exposure light can be dissolved by the developing solution. When the coated resist film is a negative resist, the portions of the resist film not exposed to exposure light can be dissolved by the developing solution. The resist film is treated with the developing solution to form a resist pattern. This resist pattern can be used as a mask to form a pattern on the semiconductor wafer.

[0260] The description of photomasks is repeated above, so the repeated content is omitted here.

[0261] Specific embodiments will be described in more detail below.

[0262] Manufacturing example: Light-shielding film formation

[0263] Example 1: A transparent quartz substrate measuring 6 inches wide, 6 inches long, and 0.25 inches thick was placed inside the chamber of a DC sputtering apparatus. A chromium target was placed inside the chamber with a T / S distance of 255 mm and an angle of 25 degrees between the substrate and the target.

[0264] Subsequently, an atmosphere gas containing 21 vol% Ar, 11 vol% N2, 32 vol% CO2 and 36 vol% He was injected into the chamber, and a sputtering process of 1.85 kW was applied to the sputtering target for 250 seconds, thereby forming the first light-shielding layer.

[0265] After the first light-shielding layer is formed, an atmosphere gas mixed with 57 vol% Ar and 43 vol% N2 is injected into the first light-shielding layer in the chamber. A power of 1.5 kW is applied to the sputtering target and a sputtering process is performed for 25 seconds, thereby producing a blank mask sample with the second light-shielding layer formed.

[0266] The sample with the second light-shielding layer film completed was placed in the chamber and subjected to heat treatment at an ambient temperature of 200°C for 15 minutes.

[0267] A cooling plate with a cooling temperature of 23°C was installed on the substrate side of the heat-treated test piece. The distance between the test piece substrate and the cooling plate was adjusted so that the cooling rate measured on the surface of the light-shielding film of the test piece reached 45°C / min, and a cooling step was performed for 5 minutes.

[0268] After cooling, the test pieces were stored in the atmosphere at a temperature greater than or equal to 20°C and less than or equal to 25°C for 120 minutes to stabilize.

[0269] The light-shielding film of the stabilized test piece was subjected to a first rinsing process. Specifically, rinsing was performed by continuously spraying carbonated water for 80 seconds at a flow rate of greater than or equal to 1000 ml / min and less than or equal to 1800 ml / min while rotating at a low speed.

[0270] After the first rinsing process, a surface oxidation treatment was performed on the surface of the light-shielding film of the test piece. Specifically, for 504 seconds, an SC-1 solution (used as an oxidant solution) with a flow rate of ≥500 mL / min and ≤1000 mL / min and hydrogen water with a flow rate of ≥500 mL / min and ≤1500 mL / min were simultaneously sprayed onto the surface of the light-shielding film. Subsequently, for 160 seconds, hydrogen water with a flow rate of ≥500 mL / min and ≤1500 mL / min was sprayed separately onto the surface of the light-shielding film.

[0271] The SC-1 solution contains 0.1% ammonia (NH4OH) by volume and 0.08% hydrogen peroxide (H2O2) by volume.

[0272] During the spraying of SC-1 solution and hydrogen water, the nozzle was repeatedly moved diagonally within the light-shielding film area of ​​the test piece.

[0273] Subsequently, while rotating the test piece at a low speed, carbonated water was continuously sprayed onto the surface of the light-shielding film of the test piece for 88 seconds at a flow rate of greater than or equal to 1000 ml / min and less than or equal to 1800 ml / min to carry out a second rinsing process.

[0274] Example 2: Blank mask specimens were manufactured under the same conditions as in Example 1. However, during the surface oxidation process, the ammonia (NH4OH) content in the SC-1 solution was 0.15% by volume.

[0275] Example 3: A blank mask sample was manufactured under the same conditions as in Example 1. However, during the surface oxidation process, the ammonia (NH4OH) content in the SC-1 solution was 0.05% by volume.

[0276] Example 4: A blank mask sample was manufactured under the same conditions as in Example 1. However, during the surface oxidation process, the ammonia (NH4OH) content in the SC-1 solution was 0.5% by volume.

[0277] Example 5: A blank mask sample was manufactured under the same conditions as in Example 1. However, during the surface oxidation process, the ammonia content in the SC-1 solution was 0.07% by volume.

[0278] Comparative Example 1: A blank mask sample was manufactured under the same conditions as in Example 1. However, after stabilization treatment, the first rinsing process, the surface oxidation process, and the second rinsing process were not applied.

[0279] Comparative Example 2: A blank mask specimen was manufactured under the same conditions as in Example 1. However, during the surface oxidation process, carbonated water with a flow rate of ≥1000 mL / min and ≤2500 mL / min was sprayed as an alternative to the oxidant solution.

[0280] Comparative Example 3: A blank mask sample was manufactured under the same conditions as in Example 1. However, during the surface oxidation process, the ammonia content in the SC-1 solution was 2% by volume.

[0281] Comparative Example 4: A blank mask specimen was manufactured under the same conditions as in Example 1. However, the heat treatment temperature during the heat treatment process was 150°C, and the cooling temperature during the cooling process was 27°C.

[0282] Comparative Example 5: A blank mask specimen was manufactured under the same conditions as in Example 1. However, a 20-minute stabilization process was performed.

[0283] The process conditions for each embodiment and comparative example are described in Table 1 below.

[0284] Evaluation Example: Evaluation of Optical Characteristic Deviation

[0285] On the surface of the light-shielding film of each of the examples and comparative examples, a measurement area of ​​132 mm wide and 132 mm long was defined at the center of the light-shielding film. The measurement area was divided into 6 equal parts in both the transverse and longitudinal directions, thus defining a total of 36 sectors. A total of 49 vertices in each sector were designated as measurement points, and the transmittance values ​​were measured at these points using a spectral ellipsometer. The optical density of Equation 1 was calculated based on these transmittance values. The average optical density value of each measurement point was calculated and used as the optical density value of the light-shielding film.

[0286] To calculate the standard deviation of the optical density values ​​and the value obtained by subtracting the minimum value from the maximum value, the optical density of the light-blocking film was measured ten times. All ten measurements were performed under identical conditions at the same measurement points.

[0287] The spectral ellipsometer used was the NanoView MG-Pro, which detected light at a wavelength of 193 nm.

[0288] The standard deviations of transmittance and reflectance, and the values ​​obtained by subtracting the minimum value from the maximum value, were calculated using the same method as for calculating the standard deviation of optical density.

[0289] The values ​​measured in each embodiment and comparative example are recorded in Table 2 below.

[0290] Evaluation example: Surface roughness evaluation

[0291] The Rsk, Rku, Rp, and Rv values ​​of the light-shielding film surface in each embodiment and comparative example are values ​​measured according to ISO 4287. The Rpv value is calculated by adding the Rp and Rv values.

[0292] Specifically, measurements were taken using a Park System XE-150 model in a 1μm wide and 1μm long area located at the center of the light-shielding film. The values ​​of Rsk, Rku, Rp, Rv, and Rpv were measured in non-contact mode at a scan rate of 0.5Hz. The XE-150 model used a Park System Cantilever PPP-NCHR probe.

[0293] The measurement results of each embodiment and comparative example are shown in Table 3 below.

[0294] [Table 1]

[0295]

[0296] [Table 2]

[0297]

[0298] [Table 3]

[0299]

[0300]

[0301] In Table 2 above, the standard deviation of optical density measured in Examples 1 to 5 is less than or equal to 0.009, while the standard deviation of optical density measured in Comparative Examples 1 to 5 is greater than 0.009.

[0302] The standard deviation of reflectance measured in Examples 1 to 5 was less than or equal to 0.032%, while the standard deviation of reflectance measured in Comparative Examples 1 to 5 was greater than 0.032%.

[0303] The values ​​obtained by subtracting the minimum value from the maximum value of optical density in Examples 1 to 5 are less than or equal to 0.02, while the values ​​obtained in Comparative Examples 1 to 5 are greater than 0.03.

[0304] The maximum reflectance measured in Examples 1 to 5 minus the minimum reflectance is less than or equal to 0.09%, while the value measured in Comparative Examples 1 to 5 is greater than 0.09%.

Claims

1. A blank mask, comprising: A light-transmitting substrate and a light-shielding film disposed on the light-transmitting substrate, The light-shielding film comprises at least one of a transition metal, oxygen, and nitrogen. The light-shielding film includes a first light-shielding layer and a second light-shielding layer disposed on the first light-shielding layer. The second light-shielding layer contains 35 at% and less than 75 at% of a transition metal. The thickness of the second light-shielding layer is 30 Å to 200 Å. When the optical density of the light-shielding film was measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density values ​​was less than or equal to 0.0055. The value obtained by subtracting the minimum value from the maximum value of the measured optical density is less than or equal to 0.

02. The Rsk value of the surface of the light-shielding film is greater than or equal to -2 and less than or equal to 0.

1.

2. The blank mask according to claim 1, wherein, The measured optical density value is the average of the optical density values ​​measured at a total of 49 measurement points on the surface of the light-shielding film. The term "ten measurements" refers to the measurement being performed at a total of 49 measurement points on the surface of the light-shielding film during each measurement, with the same measurement points being used in all ten measurements.

3. The blank mask according to claim 1, wherein, When the reflectance of the light-shielding film was measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured reflectance values ​​was less than or equal to 0.032%. The value obtained by subtracting the minimum value from the maximum value of the measured reflectance is less than or equal to 0.09%.

4. The blank mask according to claim 1, wherein, For light with a wavelength greater than or equal to 190 nm and less than or equal to 550 nm, the reflectivity of the light-shielding film is greater than or equal to 15% and less than or equal to 35%.

5. The blank mask according to claim 1, wherein, The surface Rku value of the light-shielding film is less than or equal to 3.

5.

6. The blank mask according to claim 1, wherein, The Rp value of the surface of the light-shielding film is less than or equal to 4.7 nm.

7. The blank mask according to claim 1, wherein, The Rpv value of the surface of the light-shielding film is less than or equal to 8.5 nm.

8. The blank mask according to claim 1, wherein, The content of transition metal in the second light-shielding layer is greater than that in the first light-shielding layer.

9. The blank mask according to claim 1, wherein, The transition metal includes at least one of Cr, Ta, Ti, and Hf.

10. A photomask, comprising: A light-transmitting substrate and a light-shielding pattern film disposed on the light-transmitting substrate, The light-shielding patterned film comprises at least one of a transition metal, oxygen, and nitrogen. The light-shielding pattern film includes a first light-shielding layer and a second light-shielding layer disposed on the first light-shielding layer. The second light-shielding layer contains 35 at% and less than 75 at% of a transition metal. The thickness of the second light-shielding layer is 30 Å to 200 Å. When the optical density of the upper surface of the light-shielding pattern film was measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density values ​​was less than or equal to 0.0055. The value obtained by subtracting the minimum value from the maximum value of the measured optical density is less than or equal to 0.

02. The Rsk value of the upper surface of the light-shielding pattern film is greater than or equal to -2 and less than or equal to 0.

1.

11. A method for manufacturing a semiconductor device, comprising: Preparation steps include setting up the light source, photomask, and semiconductor wafer coated with resist film. The exposure step involves selectively transmitting and emitting light incident from the light source onto the semiconductor wafer through the photomask, and The development step involves developing a pattern on the semiconductor wafer; The photomask includes a light-transmitting substrate and a light-shielding pattern film disposed on the light-transmitting substrate. The light-shielding patterned film comprises at least one of a transition metal, oxygen, and nitrogen. The light-shielding pattern film includes a first light-shielding layer and a second light-shielding layer disposed on the first light-shielding layer. The second light-shielding layer contains 35 at% and less than 75 at% of a transition metal. The thickness of the second light-shielding layer is 30 Å to 200 Å. When the optical density of the upper surface of the light-shielding pattern film was measured ten times using light with a wavelength of 193 nm, the standard deviation of the measured optical density values ​​was less than or equal to 0.0055. The value obtained by subtracting the minimum value from the maximum value of the measured optical density is less than or equal to 0.

02. The Rsk value of the upper surface of the light-shielding pattern film is greater than or equal to -2 and less than or equal to 0.1.

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