Blank mask, photomask and method of manufacturing a semiconductor element

Abstract

The present invention relates to a blank mask, a photomask, and a manufacturing method of a semiconductor element. The blank mask according to the present embodiment includes a light-transmissive substrate and a light-blocking film provided on the light-transmissive substrate. The light-blocking film includes a first light-blocking layer and a second light-blocking layer provided on the first light-blocking layer. The second light-blocking layer includes at least one of a transition metal, oxygen, and nitrogen. The reflectance of the surface of the light-blocking film with respect to light having a wavelength of 193 nm is greater than or equal to 20% and less than or equal to 40%. The hardness of the second light-blocking layer is greater than or equal to 0.3 kPa and less than or equal to 0.55 kPa. In this case, when the surface of the light-blocking film is subjected to high-sensitivity defect detection, the accuracy of defect detection can be improved, and the generation of particles during the patterning process can be effectively suppressed.

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 miniaturized 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 fine patterns 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 patterns on the wafer surface.

[0007] Existing technical documents

[0008] Patent documents

[0009] (Patent Document 1) Japanese Patent No. 6830985

[0010] (Patent Document 2) Japanese Patent Publication No. 2019-066892 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] The purpose of this embodiment is to provide a blank mask or the like that can obtain more accurate measurement values ​​while performing highly sensitive defect detection on the surface of a light-shielding film and effectively reduce the amount of particles from the light-shielding film or the like.

[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 a first light-shielding layer and a second light-shielding layer disposed on the first light-shielding layer.

[0016] The second light-shielding layer comprises at least one of a transition metal, oxygen, and nitrogen.

[0017] The surface of the light-shielding film has a reflectivity of greater than or equal to 20% and less than or equal to 40% for light with a wavelength of 193nm.

[0018] The hardness value of the second light-shielding layer is greater than or equal to 0.3 kPa and less than or equal to 0.55 kPa.

[0019] The surface reflectivity of the light-shielding film to light with a wavelength of 350 nm can be greater than or equal to 25% and less than or equal to 45%.

[0020] The reflectivity of the surface of the light-shielding film to all light with wavelengths greater than or equal to 350 nm and less than or equal to 400 nm can be in the range of greater than or equal to 25% and less than or equal to 50%.

[0021] The reflectivity of the surface of the light-shielding film to all light with wavelengths greater than or equal to 480 nm and less than or equal to 550 nm can be in the range of greater than or equal to 30% and less than or equal to 50%.

[0022] The hardness value of the second light-shielding layer can be more than 0.15 times and less than 0.55 times the hardness value of the first light-shielding layer.

[0023] The Young's modulus of the second light-shielding layer can be greater than or equal to 1.0 kPa.

[0024] The Young's modulus of the second light-shielding layer can be more than 0.15 times and less than 0.55 times the Young's modulus of the first light-shielding layer.

[0025] The absolute value of the value obtained by subtracting the transition metal content of the first light-shielding layer from the transition metal content of the second light-shielding layer can be less than or equal to 30 atoms.

[0026] The thickness ratio of the first light-shielding layer to the second light-shielding layer can be from 1:0.02 to 0.25.

[0027] 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.

[0028] The light-blocking patterned film includes a first light-blocking layer and a second light-blocking layer disposed on the first light-blocking layer.

[0029] The second light-shielding layer comprises at least one of a transition metal, oxygen, and nitrogen.

[0030] The upper surface of the light-shielding patterned film has a reflectivity of greater than or equal to 20% and less than or equal to 40% for light with a wavelength of 193nm.

[0031] The hardness value of the second light-shielding layer is greater than or equal to 0.3 kPa and less than or equal to 0.55 kPa.

[0032] 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 exposing 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.

[0033] The photomask includes a light-transmitting substrate and a light-blocking pattern film disposed on the light-transmitting substrate.

[0034] The light-blocking patterned film includes a first light-blocking layer and a second light-blocking layer disposed on the first light-blocking layer.

[0035] The second light-shielding layer comprises at least one of a transition metal, oxygen, and nitrogen.

[0036] The upper surface of the light-shielding patterned film has a reflectivity of greater than or equal to 20% and less than or equal to 40% for light with a wavelength of 193nm.

[0037] The hardness value of the second light-shielding layer is greater than or equal to 0.3 kPa and less than or equal to 0.55 kPa.

[0038] The effects of the invention

[0039] This embodiment provides a blank mask or the like that can obtain more accurate measurement values ​​while performing highly sensitive defect detection on the surface of a light-shielding film, and effectively reduce the amount of particles from the light-shielding film or the like. Attached Figure Description

[0040] Figure 1 This is a conceptual diagram illustrating a blank mask according to one embodiment disclosed in this specification.

[0041] Figure 2 This is a concept diagram describing a patterned light-blocking film formed by patterning the light-blocking film.

[0042] Figure 3 This is a conceptual diagram illustrating a blank mask according to another embodiment disclosed in this specification.

[0043] Figure 4 This is a conceptual diagram illustrating yet another embodiment of a photomask disclosed in this specification.

[0044] Figure 5 This is a graph showing the measured reflectance of the surface of the light-shielding film of Example 1 to detection light of different wavelengths.

[0045] Figure 6A This is an image of the surface of the light-shielding film in Comparative Example 1, measured using a defect detection device.

[0046] Figure 6B This is an image of the surface of the light-shielding film in Comparative Example 2, measured using a defect detection device.

[0047] Explanation of reference numerals in the attached figures

[0048] 100: Blank Mask

[0049] 10: Transparent substrate

[0050] 20: Blackout film

[0051] 21: First light-shielding layer

[0052] 22: Second light-shielding layer

[0053] 30: Phase-shifting film

[0054] 200: Photomask

[0055] 25: Light-blocking patterned film

[0056] p: Damaged portion of the light-blocking patterned film. Detailed Implementation

[0057] 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.

[0058] The terms “about”, “substantially”, etc., 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.

[0059] Throughout this specification, the term “combination thereof” as used in the Markush form refers to a mixture or combination of one or more of the components selected from the group consisting of the components described in the Markush form, and is intended to include one or more of the components selected from the group consisting of the aforementioned components.

[0060] Throughout this specification, the reference to “A and / or B” means “A, B, or A and B”.

[0061] Throughout this specification, unless otherwise stated, terms such as “first,” “second,” or “A,” “B” are used to distinguish the same terms.

[0062] 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.

[0063] 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.

[0064] In this specification, a pseudo-defect refers to a defect that occurs on the surface of the light-shielding film and 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 inspected with a highly sensitive defect detection device.

[0065] In this specification, standard deviation refers to the sample standard deviation.

[0066] 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.

[0067] High-sensitivity defect detection can be performed on the surface of light-shielding films or light-shielding patterned films formed by patterning light-shielding films. However, during high-sensitivity defect detection, the defect detection equipment may misidentify multiple false defects present on the surface of the light-shielding film or light-shielding patterned film as actual defects, making it difficult to detect genuine defects. In such cases, additional detection processes are required to distinguish genuine defects from the detection results data, which may lead to low efficiency in the production processes of blank masks and photomasks.

[0068] As a method to improve the accuracy of defect detection in light-shielding films or patterned light-shielding films, methods such as increasing the surface metal content of the light-shielding film can be applied. This can be one method of controlling the optical properties of the light-shielding film surface, such as reflectivity, to values ​​suitable for defect detection. However, light-shielding films with high surface metal content also suffer from the problem of increased particle content after patterning. These particles may cause scratches on the surface of the patterned light-shielding film and may lead to low resolution of the photomask.

[0069] The inventors of this embodiment have experimentally confirmed that by applying a multi-layered light-shielding film, controlling the reflectivity of the light-shielding film surface to a specific wavelength, and simultaneously controlling the hardness value of each layer within the light-shielding film, a blank mask can be provided that is easy to detect defects and suppresses their occurrence under high-sensitivity defect detection conditions.

[0070] This embodiment will be described in detail below.

[0071] 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.

[0072] The blank mask 100 includes a light-transmitting substrate 10 and a light-shielding film 20 located on the light-transmitting substrate 10.

[0073] 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 transmittance of the light-transmitting substrate 10 to exposure light with a wavelength of 193 nm can be greater than or equal to 85%. 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.

[0074] In addition, the light-transmitting substrate 10 can suppress the occurrence of optical distortion by adjusting surface characteristics such as flatness and roughness.

[0075] The light-shielding film 20 can be located on the top side of the light-transmitting substrate 10.

[0076] 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 3 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.

[0077] 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.

[0078] The light-shielding film 20 includes at least one of a transition metal, oxygen, and nitrogen.

[0079] The second light-shielding layer 22 includes at least one of a transition metal, oxygen, and nitrogen.

[0080] The first light-shielding layer 21 and the second light-shielding layer 22 have different transition metal contents.

[0081] Optical properties and mechanical properties of light-shielding film

[0082] Figure 2 This is a conceptual diagram describing a patterned light-shielding film formed by patterning a light-shielding film. (Refer to the above.) Figure 2 This implementation method is described.

[0083] The reflectivity of the surface of the light-shielding film 20 to light with a wavelength of 193nm is greater than or equal to 20% and less than or equal to 40%, and the hardness value of the second light-shielding layer is greater than or equal to 0.3kPa and less than or equal to 0.55kPa.

[0084] Defects present on the surface of a patterned film (hereinafter referred to as a light-shielding patterned film) formed by patterning a light-shielding film 20 can be detected using a defect detection device. Specifically, when detection light is shone onto the surface of the light-shielding patterned film 25 by the defect detection device, reflected light is generated on the surface of the light-shielding patterned film 25. The defect detection device can determine whether a defect exists at the detection location by analyzing the reflected light.

[0085] The wavelength of the detection light in a defect detection device can vary depending on the target being measured. Typically, the wavelength of the detection light in a defect detection device used to detect photomasks can be in the range of 190 nm or greater and 260 nm or less, while the wavelength of the detection light in a defect detection device used to detect blank masks can be in the range of 350 nm or greater and 400 nm or greater and 480 nm or less and 550 nm.

[0086] When the sensitivity of defect detection is set too high, the intensity of the reflected light generated during the detection process may affect the accuracy of defect detection. Specifically, a large number of false defects may be detected, causing the detection data corresponding to the real defects to be hidden, or the surface image of the light-shielding pattern film 25 may be distorted due to excessively high intensity reflected light incident on the lens of the detection equipment.

[0087] A method to further increase the transition metal content of the light-shielding film or light-shielding pattern film 25 could be considered, allowing for the formation of more intense reflected light on the surface of the light-shielding pattern film 25. In this case, even if the defect detection sensitivity is set to a high value, the detection frequency of false defects may decrease; however, the amount of particles from the light-shielding film or light-shielding pattern film 25 may increase during or after the patterning process. In particular, most of these particles may originate from damaged portions p of the light-shielding pattern film.

[0088] This embodiment controls the reflectivity of the surface of the light-shielding film 20 to light with a wavelength of 193nm, while also controlling the hardness value of the second light-shielding layer 22. This allows for more accurate detection of true defects on the surface of the light-shielding pattern film, while further improving the durability of the light-shielding pattern film (especially the upper corners of the light-shielding pattern film).

[0089] The reflectivity of the light-shielding film surface and the hardness of the second light-shielding layer can be adjusted by controlling the proportion of reactive gases used in the film formation of each light-shielding layer, the composition of the reactive gases, the sputtering power, the pressure of the atmospheric gas, and the heat treatment and cold treatment conditions.

[0090] The reflectance of the light-shielding film 20 is measured using a spectroscopic ellipsometry. As an example, the reflectance of the light-shielding film 20 can be measured using the NanoView MG-Pro.

[0091] Hardness can be measured using an atomic force microscope (AFM). Specifically, a Park Systems AFM instrument (model XE-150) was used in contact mode at a scan rate of 0.5 Hz, and measurements were performed using the Park Systems Cantilever model (PPP-CONTSCR). Adhesive forces and other parameters were measured at 16 locations within the object being measured, and the average value was taken as the hardness value. A silicon Berkovich tip (Poisson's ratio at the tip: 0.07) was used for the measurement, and the hardness measurement results were obtained by applying the Oliver and Phar Model using a program provided by the AFM instrument company.

[0092] The reflectivity of the surface of the light-shielding film 20 to light with a wavelength of 193 nm can be greater than or equal to 20% and less than or equal to 40%. The reflectivity can be greater than or equal to 22%. The reflectivity can be greater than or equal to 25%. The reflectivity can be greater than or equal to 27%. The reflectivity can be less than or equal to 35%. The reflectivity can be less than or equal to 33%.

[0093] The hardness of the second light-shielding layer 22 can be greater than or equal to 0.3 kPa and less than or equal to 0.55 kPa. The hardness of the second light-shielding layer 22 can be greater than or equal to 0.4 kPa. The hardness of the second light-shielding layer 22 can be greater than or equal to 0.45 kPa. The hardness of the second light-shielding layer 22 can be less than or equal to 0.52 kPa. The hardness of the second light-shielding layer 22 can be less than or equal to 0.5 kPa.

[0094] In this case, when patterning the light-shielding film 20 and then performing pattern detection, the detection frequency of false defects can be effectively reduced, and the amount of particles generated from the patterned light-shielding film can be reduced.

[0095] The reflectivity of the surface of the light-shielding film 20 to light with a wavelength of 350 nm can be greater than or equal to 25% and less than or equal to 45%. The reflectivity can be greater than or equal to 27%. The reflectivity can be greater than or equal to 30%. The reflectivity can be less than or equal to 40%. In this case, the frequency of false defect detection can be effectively reduced when performing defect detection on the surface of the light-shielding film.

[0096] The defect detection device using a blank mask can apply detection light wavelengths within the ranges of 350 nm to 400 nm and 480 nm to 550 nm. This embodiment allows control over the reflectivity characteristics of the light-shielding film 20 for all light within the aforementioned wavelength ranges. Therefore, the impact of reflected light intensity on the accuracy of defect detection can be reduced.

[0097] The surface of the light-shielding film 20 can have a reflectivity of 25% to 50% for light with a wavelength greater than or equal to 350 nm and less than or equal to 400 nm. Alternatively, the reflectivity can be greater than or equal to 28%. Or, the reflectivity can be greater than or equal to 30%. Or, the reflectivity can be less than or equal to 45%. Or, the reflectivity can be less than or equal to 40%.

[0098] The surface of the light-shielding film 20 may have a reflectivity of 30% to 50% for light with a wavelength greater than or equal to 480 nm and less than or equal to 550 nm. The reflectivity may be greater than or equal to 35%. The reflectivity may be greater than or equal to 38%. The reflectivity may be less than or equal to 45%. The reflectivity may be less than or equal to 42%.

[0099] In this case, when performing defect detection on the light-shielding film, the decrease in defect detection accuracy caused by flare phenomenon can be suppressed, and the detection frequency of false defects can be effectively reduced.

[0100] The hardness value of the second light-shielding layer 22 can be more than 0.15 times and less than 0.55 times the hardness value of the first light-shielding layer 21.

[0101] This embodiment utilizes a multi-layered light-shielding film and can control the ratio of the hardness value of the second light-shielding layer 22 to the hardness value of the first light-shielding layer 21 within the light-shielding film. Therefore, while further improving the durability of the upper corner portion of the light-shielding pattern film 25, a more precise shape of the light-shielding pattern film can be controlled by adjusting the etching rate ratio of the etching gas to the first light-shielding layer 21 and the second light-shielding layer 22.

[0102] The hardness value of the second light-shielding layer 22 is 0.15 times or more and 0.55 times or less than the hardness value of the first light-shielding layer 21. The hardness value of the second light-shielding layer 22 is 0.2 times or more than the hardness value of the first light-shielding layer 21. The hardness value of the second light-shielding layer 22 is 0.3 times or more than the hardness value of the first light-shielding layer 21. The hardness value of the second light-shielding layer 22 is 0.5 times or less than the hardness value of the first light-shielding layer 21. The hardness value of the second light-shielding layer 22 is 0.4 times or less than the hardness value of the first light-shielding layer 21. In this case, the amount of particles from the light-shielding pattern film can be reduced. Furthermore, it can effectively prevent the formation of step differences on the side of the light-shielding pattern film.

[0103] The hardness of the first light-shielding layer 21 can be greater than or equal to 1 kPa and less than or equal to 3 kPa. The hardness of the first light-shielding layer 21 can be greater than or equal to 1.1 kPa. The hardness of the first light-shielding layer 21 can be greater than or equal to 1.3 kPa. The hardness of the first light-shielding layer 21 can be less than or equal to 2.5 kPa. In this case, the first light-shielding layer 21 can have stable durability. Furthermore, during dry etching, by adjusting the etching rate of the first light-shielding layer 21 to a value that is relatively higher than the etching rate of the second light-shielding layer 22, it is helpful to make the side of the light-shielding pattern film closer to the surface perpendicular to the light-transmitting substrate through dry etching.

[0104] This embodiment allows control over the Young's modulus values ​​and the ratio of Young's modulus values ​​of the second light-shielding layer 22 and the first light-shielding layer 21. Therefore, damage to the light-shielding film 20 can be effectively prevented even when external forces, including cleaning processes, are applied to its surface.

[0105] The Young's modulus values ​​of the second light-shielding layer 22 and the first light-shielding layer 21 can be adjusted not only by controlling the composition of each light-shielding layer, but also by controlling the composition of the atmospheric gas in the chamber during the formation of each light-shielding layer film, heat treatment and cooling conditions.

[0106] The method for measuring the Young's modulus of the first light-shielding layer 21 and the second light-shielding layer 22 can be performed using the same equipment as that used in the method for measuring hardness described above.

[0107] The Young's modulus of the second light-shielding layer 22 can be greater than or equal to 1.0 kPa. The Young's modulus of the second light-shielding layer 22 can be greater than or equal to 1.2 kPa. The Young's modulus of the second light-shielding layer 22 can be greater than or equal to 2.3 kPa. The Young's modulus of the second light-shielding layer 22 can be less than or equal to 4.2 kPa. The Young's modulus of the second light-shielding layer 22 can be less than or equal to 3.7 kPa. The Young's modulus of the second light-shielding layer 22 can be less than or equal to 3.5 kPa. In this case, the etching rate of the second light-shielding layer 22 can be prevented from being too slow due to dry etching, and at the same time, damage to the second light-shielding layer 22 due to cleaning processes, etc., can be effectively prevented.

[0108] The Young's modulus of the first light-shielding layer 21 can be greater than or equal to 7 kPa and less than or equal to 13 kPa. The Young's modulus of the first light-shielding layer 21 can be greater than or equal to 8 kPa. The Young's modulus of the first light-shielding layer 21 can be less than or equal to 12 kPa. The Young's modulus of the first light-shielding layer 21 can be less than or equal to 11.8 kPa. In this case, when the light-shielding film 20 is dry-etched, the side surface of the first light-shielding layer 21 can be formed to be nearly perpendicular to the surface of the light-transmitting substrate 10, and the durability of the first light-shielding layer 21 can be stably controlled.

[0109] The Young's modulus of the second light-shielding layer 22 can be more than 0.15 times and less than 0.55 times the Young's modulus of the first light-shielding layer 21. Alternatively, the Young's modulus of the second light-shielding layer 22 can be more than 0.20 times the Young's modulus of the first light-shielding layer 21. Or, the Young's modulus of the second light-shielding layer 22 can be more than 0.23 times the Young's modulus of the first light-shielding layer 21. Or, the Young's modulus of the second light-shielding layer 22 can be less than 0.45 times the Young's modulus of the first light-shielding layer 21. Or, the Young's modulus of the second light-shielding layer 22 can be less than 0.42 times the Young's modulus of the first light-shielding layer 21. In this case, the number of particles generated on the surface of the light-shielding film 20 in environments with external forces, including cleaning processes, can be reduced.

[0110] Separation force, adhesion force, etc., can also be obtained by using AFM measurement. The separation force and / or adhesion force measured at 16 different locations have small deviations in the overall measurement values, which means that the light-shielding film 20 has uniform physical properties at all measurement locations.

[0111] The standard deviation of the adhesion energy measured at 16 different locations on the second light-shielding layer 22 (preferably locations spaced at least 1 cm apart) can be less than 8%, 6%, or 5% of the average adhesion energy. The standard deviation can be greater than 0.001% of the average adhesion energy. Even if the blank mask 100 or photomask with these characteristics forms a fine pattern overall, it can still have a uniform particle formation reduction effect.

[0112] The adhesion of the second light-shielding layer 22 can be greater than or equal to 0.25 fJ. The adhesion of the second light-shielding layer 22 can be greater than or equal to 0.30 fJ. The adhesion of the second light-shielding layer 22 can be less than or equal to 0.4 fJ.

[0113] The adhesion of the second light-shielding layer 22 can be at least 0.10 fJ greater than the adhesion of the first light-shielding layer 21. The adhesion of the second light-shielding layer 22 can be at most 0.15 fJ greater than the adhesion of the first light-shielding layer 21.

[0114] The standard deviation of the pull-off force measured at 16 different locations on the second light-shielding layer 22 can be less than 5%, less than 3%, or less than 2% of the average pull-off force. The standard deviation can be greater than 0.001% of the average pull-off force. A blank mask 100 or photomask having these characteristics can have an overall uniform scratch formation reduction effect.

[0115] The separation force of the second light-shielding layer 22 can be greater than or equal to 4.0 nN. The separation force of the second light-shielding layer 22 can be greater than or equal to 4.1 nN. The separation force of the second light-shielding layer 22 can be less than or equal to 4.8 nN.

[0116] The separation force of the second light-shielding layer 22 can be at least 0.6 nN greater than that of the first light-shielding layer 21. The separation force of the second light-shielding layer 22 can be up to 1.2 nN greater than that of the first light-shielding layer 21.

[0117] The transmittance and optical density of the light-shielding film 20 were measured using a spectroscopic ellipsometry. As an example, the reflectance of the light-shielding film 20 can be measured using the NanoView MG-Pro.

[0118] The light-shielding film 20 has a transmittance of 1% or greater than or equal to 1% for light with a wavelength of 193 nm. The transmittance can be 1.33% or greater than or equal to 1.38%. The transmittance can be 1.4% or greater than or equal to 1.6%.

[0119] The light-shielding film 20 can have an optical density of less than or equal to 2.0 for light with a wavelength of 193nm. The optical density can be less than or equal to 1.87. The optical density can be greater than or equal to 1.8. The optical density can be greater than or equal to 1.83.

[0120] In this case, the light-blocking film 20 can effectively block the exposure light together with the phase-shifting film.

[0121] Layer structure of light-shielding film

[0122] 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. The second light-shielding layer 22 may be formed to contact the first light-shielding layer 21 on the first light-shielding layer 21. Other thin films may be disposed between the second light-shielding layer 22 and the first light-shielding layer 21.

[0123] The first light-shielding layer 21 and the second light-shielding layer 22 can have a thickness ratio of 1:0.02 to 0.25. Alternatively, the first light-shielding layer 21 and the second light-shielding layer 22 can have a thickness ratio of 1:0.04 to 0.18. The light-shielding film 20, including both the first light-shielding layer 21 and the second light-shielding layer 22, can satisfy the desired conditions for transmittance and optical density, and also possess the characteristics of suppressing particle generation and reducing scratches.

[0124] The thickness of the light-shielding film 20 can be from 30 nm to 80 nm. Alternatively, the thickness can be from 40 nm to 70 nm. In this case, the effect of reducing particle formation can be even better.

[0125] The thickness or thickness ratio can be determined by layering, etc., as confirmed by micrographs of the cross section, and any method that can determine the thickness can be applied without limitation.

[0126] 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-shielding layer 21 can help the light-shielding film 20 effectively block the exposure light.

[0127] 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, it can help the light-shielding film 20 to have a surface reflectance value within a preset range in this embodiment, 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.

[0128] Components of a light-shielding film

[0129] This embodiment allows control over the content of various elements in each layer of the light-shielding film 20. Therefore, while imparting light-shielding properties to the light-shielding film 20, it can help improve the accuracy of defect detection when inspecting the light-shielding film 20 or the light-shielding patterned film. Furthermore, by influencing the mechanical properties of each layer in the light-shielding film 20, it can help reduce the amount of particles from the patterning process of the light-shielding film 20 or from the already patterned light-shielding patterned film.

[0130] However, the mechanical properties of each layer in the light-shielding film 20 are affected not only by the composition of each layer, but also by the density of each layer, the crystallinity of the elements contained in each layer, and the arrangement of the elements. This embodiment can adjust the mechanical properties of each layer in the light-shielding film 20 by controlling the sputtering power applied during the sputtering process of each layer, the content of inert gas in the atmosphere gas, and the composition of the reactant gas, while simultaneously controlling the composition of each layer. Specific details will be described later.

[0131] 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.

[0132] 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 25 at% or more. The content can be 70 at% or less. The content can be 65 at% or less. The content can be 60 at% or less.

[0133] The second light-shielding layer 22 may contain more than 10 at% oxygen. The second light-shielding layer 22 may contain more than 15 at% oxygen. The second light-shielding layer 22 may contain more than 20 at% oxygen. The second light-shielding layer 22 may contain less than 40 at% oxygen. The second light-shielding layer 22 may contain less than 35 at% oxygen. The second light-shielding layer 22 may contain less than 30 at% oxygen.

[0134] The second light-shielding layer 22 may contain 5 at% or more nitrogen. The second light-shielding layer 22 may contain 10 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. The second light-shielding layer 22 may contain less than 22 at% nitrogen.

[0135] The second light-shielding layer 22 may contain 1 at% or more carbon. The second light-shielding layer 22 may contain 3 at% or more carbon. The second light-shielding layer 22 may contain less than 25 at% carbon. The second light-shielding layer 22 may contain less than 20 at% carbon. The second light-shielding layer 22 may contain less than 15 at% carbon.

[0136] In this case, the light-shielding film 20 can have surface reflectivity characteristics that facilitate defect detection. Furthermore, it can help to further improve the durability of the surface portion of the light-shielding film 20.

[0137] 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 45 at% of a transition metal. The first light-shielding layer 21 may contain less than 40 at% of a transition metal. The first light-shielding layer 21 may contain less than 35 at% of a transition metal.

[0138] 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 35 at% or more. The sum of the oxygen and nitrogen content of the first light-shielding layer 21 can be 75 at% or less. The sum of the oxygen and nitrogen content of the first light-shielding layer 21 can be 65 at% or less.

[0139] 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 55 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.

[0140] 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.

[0141] 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 30 at% carbon. The first light-shielding layer 21 may contain less than 25 at% carbon.

[0142] In this case, the first light-shielding layer 21 can help the light-shielding film 20 to have excellent light-extinguishing properties. In addition, during dry etching, the first light-shielding layer 21 can help to exhibit a relatively higher etching rate compared to the second light-shielding layer 22.

[0143] The difference between the content of each element in the second light-shielding layer 22 and the content of each element in the first light-shielding layer 21 can be controlled. Specifically, the first light-shielding layer 21 and the second light-shielding layer 22 can be configured to be in contact with each other. In this case, by controlling the composition between the first light-shielding layer 21 and the second light-shielding layer 22, especially by controlling the difference in the content of transition metals, the difference in physical properties such as surface energy between the first light-shielding layer 21 and the second light-shielding layer 22 can be adjusted. As a result, atoms on the surface of the first light-shielding layer 21 at the interface between the first light-shielding layer 21 and the second light-shielding layer 22 can easily form bonds with atoms on the surface of the second light-shielding layer 22, and the generation of defects due to insufficient adhesion between the first light-shielding layer 21 and the second light-shielding layer 22 can be effectively suppressed.

[0144] The absolute value of the value obtained by subtracting the transition metal content of the first light-shielding layer 21 from the transition metal content of the second light-shielding layer 22 can be less than or equal to 30 atomic%. The absolute value can be less than or equal to 25 atomic%. The absolute value can be less than or equal to 20 atomic%. The absolute value can be greater than or equal to 7 atomic%. The absolute value can be greater than or equal to 10 atomic%. The absolute value can be greater than or equal to 12 atomic. In this case, the adhesion between the first light-shielding layer 21 and the second light-shielding layer 22 can be improved.

[0145] The transition metal may include at least one of Cr, Ta, Ti, and Hf. The transition metal may be Cr.

[0146] Other films

[0147] Figure 3 This is a conceptual diagram illustrating a blank mask according to yet another embodiment of this specification. Referring to the above... Figure 3 The blank mask described in this embodiment.

[0148] 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.

[0149] The phase-shifting film 30 comprises a transition metal and silicon.

[0150] The description of the light-shielding film 20 is the same as the foregoing content, and the repeated description is omitted here.

[0151] 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.

[0152] The phase difference between the phase shift film 30 and light with a wavelength of 193 nm can be 170° to 190°. The phase difference between the phase shift film 30 and light with a wavelength of 193 nm can be 175° to 185°. The transmittance of the phase shift film 30 to light with a wavelength of 193 nm can be 3% to 10%. The transmittance of the phase shift film 30 to light with a wavelength of 193 nm can be 4% to 8%. In this case, the resolution of the photomask including the phase shift film 30 can be improved.

[0153] 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.

[0154] 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.

[0155] A hard mask (not shown) can be placed on the light-shielding film 20. The hard mask functions as an etching mask when etching the pattern of the light-shielding film 20. The hard mask may include silicon, nitrogen, and oxygen.

[0156] Photomask

[0157] Figure 4 This is a conceptual diagram illustrating a photomask according to yet another embodiment of this specification. Referring to the above... Figure 4 The photomask of this embodiment is described.

[0158] 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.

[0159] The light-blocking pattern film 25 includes a first light-blocking layer 21 and a second light-blocking layer 22 disposed on the first light-blocking layer 21.

[0160] The light-blocking patterned film 25 includes at least one of a transition metal, oxygen, and nitrogen.

[0161] The second light-shielding layer 22 includes at least one of a transition metal, oxygen, and nitrogen.

[0162] The upper surface of the light-shielding pattern film 25 has a reflectivity of greater than or equal to 20% and less than or equal to 40% for light with a wavelength of 193nm.

[0163] The hardness value of the second light-shielding layer 22 is greater than or equal to 0.3 kPa and less than or equal to 0.55 kPa.

[0164] A light-shielding patterned film 25 can be formed by patterning the light-shielding film 20 of the aforementioned blank mask 100.

[0165] 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 film 20 of the blank mask 100, and the repeated description is omitted here.

[0166] Manufacturing method of light-blocking film

[0167] A method for manufacturing a blank mask according to one embodiment of this specification may include: a preparation step of setting a substrate and a sputtering target in a sputtering chamber.

[0168] 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 substrate.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] A method for manufacturing a blank mask according to one embodiment of this specification may include a stabilization step, in which the blank mask after a cooling step is stabilized in an atmosphere of 10°C or higher and 60°C or lower.

[0173] In the preparation step, the composition of the light-shielding film can be considered when selecting the target material for forming the light-shielding film. 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 a transition metal can contain 90 at% or more of the transition metal. The target containing a transition metal can contain 95 at% or more of the transition metal. The target containing a transition metal can contain 99 at% of the transition metal.

[0174] Transition metals may include at least one of Cr, Ta, Ti, and Hf. Cr may be a transition metal.

[0175] The substrate disposed inside the sputtering chamber can be a light-transmitting substrate or a light-transmitting substrate on which a phase-shifting film is deposited.

[0176] 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.

[0177] In the film-forming process of the light-shielding film, different film-forming process conditions can be applied when forming films for each layer of the light-shielding film. In particular, considering the optical properties and mechanical properties of the light-shielding film, such as reflectivity and optical density, various process conditions such as atmospheric gas composition, power applied to the sputtering target, and film-forming time can be applied differently to each layer.

[0178] 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.

[0179] Inert gases can include helium.

[0180] 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.

[0181] The sputtering gas can be Ar gas.

[0182] The power supply used to apply power to the sputtering target can be a DC power supply or an RF power supply.

[0183] During the deposition 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. Alternatively, 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. In this case, during dry etching, the mechanical properties of the first light-shielding layer can be adjusted to help it achieve a stable etching rate during dry etching.

[0184] During the formation of the first light-shielding layer, the atmosphere gas injected into the sputtering chamber may include sputtering gas and inert gas. During sputtering, by controlling the content of inert gas in the atmosphere gas, it is possible to help control the mechanical properties of the film to be formed, such as density and hardness, within a predetermined range in this embodiment.

[0185] In the atmospheric gas, the inert gas content (volume %) can be more than 1 times the sputtering gas content (volume %). The inert gas content (volume %) can be more than 1.2 times the sputtering gas content (volume %). The inert gas content (volume %) can be more than 1.5 times the sputtering gas content (volume %). The inert gas content (volume %) can be less than 3 times the sputtering gas content (volume %). The inert gas content (volume %) can be less than 2.5 times the sputtering gas content (volume %). The inert gas content (volume %) can be less than 2.2 times the sputtering gas content (volume %).

[0186] The inert gas content in the total atmosphere can be greater than or equal to 20% by volume. The content can be greater than or equal to 25% by volume. The content can be greater than or equal to 30% by volume. The content can be less than or equal to 50% by volume. The content can be less than or equal to 45% by volume. The content can be less than or equal to 40% by volume.

[0187] In this case, the hardness value of the first light-shielding layer can be adjusted to a preset range in this embodiment.

[0188] The ratio of oxygen (atomic %) to nitrogen (atomic %) in the reactant gas can be greater than or equal to 1.5 and less than or equal to 4. The ratio of oxygen (atomic %) to nitrogen (atomic %) in the reactant gas can be greater than or equal to 2 and less than or equal to 3. The ratio of oxygen (atomic %) to nitrogen (atomic %) in the reactant gas can be greater than or equal to 2.2 and less than or equal to 2.7.

[0189] In this case, it can help reduce the amount of particles generated from the first light-shielding layer, and during dry etching, the etching rate of the first light-shielding layer can be increased compared to the second light-shielding layer.

[0190] 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.

[0191] 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.

[0192] 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. Alternatively, 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. In this case, the hardness, Young's modulus, and other properties of the second light-shielding layer can be controlled within the preset range of this embodiment.

[0193] During the formation of the second light-shielding layer, the ratio of the content (volume%) of the reactant gas in the atmosphere to the content (volume%) of the sputtering gas can be greater than or equal to 0.3 and less than or equal to 0.8. The ratio of these contents (volume%) can be greater than or equal to 0.4 and less than or equal to 0.6.

[0194] During the film formation process of the second light-shielding layer, the ratio of oxygen content (atomic %) to nitrogen content (atomic %) in the reactant gas can be less than or equal to 0.3. The ratio of oxygen content (atomic %) to nitrogen content (atomic %) in the reactant gas can be less than or equal to 0.1. The ratio of oxygen content (atomic %) to nitrogen content (atomic %) in the reactant gas can be greater than or equal to 0.001.

[0195] In this case, it can help improve the durability of the upper part of the light-shielding patterned film formed by patterning the light-shielding film, and can improve the accuracy of defect detection on the light-shielding film or the light-shielding patterned film formed by patterning the light-shielding film.

[0196] 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 can be greater than or equal to 15 seconds and less than or equal to 25 seconds. In this case, it facilitates finer patterning of the light-shielding film during dry etching.

[0197] The ratio of the reactive gas content (volume %) applied during the formation of the second light-shielding layer to the reactive gas content (volume %) applied during the formation of the first light-shielding layer can be greater than or equal to 0.7 and less than or equal to 1.1. The ratio can be greater than or equal to 0.8 and less than or equal to 1.05. The ratio can be greater than or equal to 0.85 and less than or equal to 0.95. In this case, it is easier to control the hardness and Young's modulus ratio of the first and second light-shielding layers.

[0198] 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.

[0199] By heat-treating the light-shielding film, the stress formed in the film can be removed, and the density of the film can be further increased. During heat treatment, the transition metals within the film can be recovered and recrystallized, effectively removing the stress. However, during the heat treatment process, when process conditions such as temperature and time are not controlled, grain growth occurs in the film. Due to the uncontrolled size of the transition metal grains, the arrangement of transition metal atoms within the film is significantly deformed compared to before heat treatment. This can affect the film's density, hardness, and other mechanical properties, as well as its surface roughness characteristics, potentially altering its reflectivity.

[0200] 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 for the effective removal of internal stress formed in the light-shielding film, while also ensuring that each layer of the light-shielding film has the mechanical properties preset in this embodiment, and helps to ensure that the reflectivity value of the surface of the light-shielding film has a value suitable for defect detection.

[0201] The heat treatment step can be carried out at temperatures ranging from 150°C to 330°C. The heat treatment step can also be carried out at temperatures ranging from 180°C to 280°C.

[0202] The heat treatment process can last from 5 to 30 minutes. Alternatively, it can last from 10 to 20 minutes. These times do not include the heating time.

[0203] 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.

[0204] 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 provided on the substrate side of the blank mask after the heat treatment step, thereby cooling the blank mask. In the cooling step, the cooling rate of the blank mask can be controlled by adjusting the gap between the blank mask and the cooling plate, and by introducing process conditions such as atmospheric gases.

[0205] 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.

[0206] Pins of adjustable length are installed at each corner of the cooling plate, and the blank mask is positioned on the pins with the substrate facing the cooling plate, thereby controlling the cooling rate of the blank mask.

[0207] 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.

[0208] As an example, the inert gas could be helium.

[0209] 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.

[0210] During the cooling step, the gap between the blank mask and the cooling plate can be from 0.01 mm to 30 mm. The gap can be from 0.05 mm to 5 mm. The gap can be from 0.1 mm to 2 mm.

[0211] 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.

[0212] In this case, the grain growth of transition metal caused by residual heat in the heat-treated light-shielding film can be suppressed, thereby enabling each layer inside the light-shielding film to have a hardness value within the range preset in this embodiment, and helping the surface of the light-shielding film to have reflectivity characteristics suitable for defect detection.

[0213] The stabilization step stabilizes the blank mask after the cooling step. This prevents damage to the blank mask caused by rapid temperature changes.

[0214] 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.

[0215] Semiconductor device manufacturing method

[0216] 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 exposing 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.

[0217] The photomask includes a light-transmitting substrate and a light-blocking pattern film disposed on the light-transmitting substrate.

[0218] The light-blocking patterned film includes a first light-blocking layer and a second light-blocking layer disposed on the first light-blocking layer.

[0219] The light-blocking patterned film 25 includes at least one of a transition metal, oxygen, and nitrogen.

[0220] The second light-shielding layer 22 includes at least one of a transition metal, oxygen, and nitrogen.

[0221] The upper surface of the light-shielding patterned film has a reflectivity of greater than or equal to 20% and less than or equal to 40% for light with a wavelength of 193nm.

[0222] The hardness value of the second light-shielding layer is greater than or equal to 0.3 kPa and less than or equal to 0.55 kPa.

[0223] 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.

[0224] 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 the exposure process of ArF semiconductor wafers. As an example, the lens could be made of calcium fluoride (CaF2).

[0225] During the exposure step, exposure light can be selectively transmitted onto the semiconductor wafer through a photomask. In this case, the portions of the resist film that have been exposed to the exposure light may undergo chemical modification.

[0226] In the developing step, a developing solution is used to treat the semiconductor wafer that has undergone 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 that have been exposed to light can be dissolved by the developing solution. When the coated resist film is a negative resist, the portions of the resist film that have not been exposed to 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.

[0227] The description of photomasks is repeated above, so the repeated content is omitted here.

[0228] Specific embodiments will be described in more detail below.

[0229] Manufacturing example: Manufacturing light-blocking film

[0230] Example 1: A substrate with a phase difference of approximately 180° for light with a wavelength of 193nm was manufactured on a synthetic quartz light-transmitting substrate that is 6 inches wide, 6 inches long, and 0.25 inches thick, and then applied to the manufacturing process of the light-shielding film described below.

[0231] The substrate is placed in the chamber of a DC sputtering apparatus, and the T / S distance of the chromium target is set to 255 mm, so that the angle between the substrate and the target is 25 degrees. The power applied during the deposition of the first light-shielding layer is 1.85 kW, and the power applied during the deposition of the second light-shielding layer is 1.5 kW.

[0232] Sputtering is performed as shown in Table 1 while the substrate is rotating, and a light-shielding film is formed by sequentially forming a first light-shielding layer and a second light-shielding layer. The light-shielding film is then heat-treated at 200°C for 15 minutes in the same manner, and then cooled with dry air at 20°C for 5 minutes to complete the heat treatment.

[0233] The process conditions for each embodiment and comparative example are described in Table 1 below.

[0234] Evaluation example: Component evaluation

[0235] The transition metal elements, specifically the chromium content, within the light-shielding films of each embodiment and comparative example were analyzed and measured using XPS. Specifically, samples were prepared by machining blank masks of each embodiment and comparative example to a size of 15 mm wide and 15 mm long. The samples were placed inside a Thermo Scientific K-Alpha measuring instrument, and a 4 mm long and 2 mm wide region located at the center of the sample was etched, and the chromium content of each layer was measured. The measurement results for each embodiment and comparative example are shown in Table 2 below.

[0236] Evaluation example: Optical property evaluation

[0237] The transmittance and optical density of the light-shielding films of each embodiment and comparative example to light with a wavelength of 193 nm were measured using a spectroscopic ellipsometry.

[0238] In addition, the reflectance of the surface of the light-shielding film of Example 1 according to the wavelength of the detection light was measured using a spectroscopic ellipsometry. Specifically, the wavelength of the detection light was gradually increased from 190 nm in 1 nm increments, and the reflectance of the surface of the light-shielding film of Example 1 to different wavelengths was measured. The measured reflectance values ​​obtained from the regression analysis are then graphically presented.

[0239] The spectroscopic ellipsometry used to evaluate optical properties is the MG-Pro manufactured by Nano-View.

[0240] The transmittance and optical density measurements of each embodiment and comparative example are recorded in Table 3 below.

[0241] The graph obtained by measuring the reflectance of the light-shielding film surface of Example 1 to detection light of different wavelengths is shown in the figure. Figure 5 middle.

[0242] Evaluation example: Mechanical performance evaluation

[0243] Hardness, Young's modulus, separation force, and adhesion force were measured using an atomic force microscope (AFM). Measurements were performed using a Park Systems XE-150 AFM instrument in contact mode at a scan rate of 0.5 Hz, employing a Park Systems PPP-CONTSCR cantilever model. After measuring the adhesion force at 16 locations inside the object, the average value was taken, and the resulting hardness or Young's modulus values ​​are shown in Table 3 below.

[0244] The measured data at 16 locations in Example 2 are shown in Table 4. The measuring head used during the measurement was a silicon Berkovich tip (Poisson's ratio at the tip: 0.07). The hardness and Young's modulus measurements were obtained by applying the Oliver and Pharr Model using a program provided by AFM Equipment Company.

[0245] Evaluation example: Etching performance evaluation

[0246] The thickness of the light-shielding film was measured using transmission electron microscopy (TEM) images of the film included in the samples of the examples and comparative examples. The samples were machined to a size of 15 mm wide and 15 mm long. The surface of the machined samples was treated with focused ion beam (FIB) using a Thermo Fisher Helios 5HX DualBeam System, and then placed in a JEOL LTD JEM-2100F HR instrument, thereby measuring the TEM images of the samples. The thickness of the light-shielding film was calculated from the TEM images.

[0247] Next, the etching time of the light-shielding film with chlorine-based gas was measured. The chlorine-based gas used contained 90 to 95 vol% chlorine and 5 to 10 vol% oxygen. The etching rate of the light-shielding film to the chlorine-based gas was calculated from the thickness of the light-shielding film and the etching time of the light-shielding film.

[0248] The etching rate measurement results for each embodiment and comparative example are shown in Table 3 below.

[0249] Evaluation example: Defect evaluation

[0250] The presence of defects on the surface of the light-shielding film of Comparative Examples 1 and 2 was measured using a defect inspection device. Specifically, an HF filter was applied to an M6641S inspection device from LASERTEC Corporation, and images of the surface of the light-shielding film of Comparative Examples 1 and 2 were then measured.

[0251] Images of the light-shielding film surfaces of Comparative Examples 1 and 2 are shown in the figures below. Figure 6A and Figure 6B middle.

[0252] [Table 1]

[0253]

[0254] * The ratio (by volume) of the reactive gas applied when forming the second light-shielding layer to the reactive gas applied when forming the first light-shielding layer.

[0255] [Table 2]

[0256]

[0257]

[0258] [Table 3]

[0259]

[0260] *The hardness ratio is the ratio of the hardness of the second light-shielding layer to the hardness of the first light-shielding layer.

[0261] *The Young's modulus ratio is the ratio of the Young's modulus of the second light-shielding layer to the Young's modulus of the first light-shielding layer.

[0262] [Table 4]

[0263]

[0264] like Figure 5 As shown, the surface reflectance of the light-shielding film of Example 1 exhibits a reflectance of ≥25% and ≤35% at wavelengths greater than or equal to 190nm and less than or equal to 260nm, a reflectance of ≥30% and ≤45% at wavelengths greater than or equal to 350nm and less than or equal to 400nm, and a reflectance of ≥35% and ≤45% at wavelengths greater than or equal to 480nm and less than or equal to 550nm.

[0265] In Table 3, the hardness ratios of Examples 1 to 3 are greater than or equal to 0.15 and less than or equal to 0.55. In contrast, Comparative Example 1 shows a result greater than 0.6, and Comparative Example 2 shows a result less than 0.11.

[0266] The Young's modulus ratios of Examples 1 to 3 are greater than or equal to 0.15 and less than or equal to 0.55. In contrast, Comparative Example 1 shows a Young's modulus ratio greater than 0.6, and Comparative Example 2 shows a Young's modulus ratio less than 0.11.

[0267] Regarding the etching rate, Examples 1 to 3, Comparative Example 1, and Comparative Example 2 illustrate... The above rates are shown in Comparative Example 3. The etching rate.

[0268] Regarding adhesion and separation forces, in Example 2, the ratio of the standard deviation of the first and second light-shielding layers to the average separation force is less than 3%, and the ratio of the standard deviation to the average adhesion force is less than 6%.

[0269] exist Figure 6A and Figure 6B In the study, it was confirmed that the surface of Comparative Example 1 contained numerous particles and scratches caused by these particles. Although the size and number of particles were reduced on the surface of Comparative Example 2 compared to Comparative Example 1, the generation of a large number of particles was still confirmed.

[0270] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts of the present invention as defined in the appended claims should also fall within the scope of the claims.

Claims

1. A blank mask, wherein, include: Transparent substrate, and A light-shielding film is disposed on the light-transmitting substrate; 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 comprises at least one of a transition metal, oxygen, and nitrogen. The surface of the light-shielding film has a reflectivity of greater than or equal to 20% and less than or equal to 40% for light with a wavelength of 193nm. The hardness value of the second light-shielding layer is greater than or equal to 0.3 kPa and less than or equal to 0.55 kPa. The hardness value of the second light-shielding layer is more than 0.15 times and less than 0.55 times the hardness value of the first light-shielding layer.

2. The blank mask according to claim 1, wherein, The surface of the light-shielding film has a reflectivity of greater than or equal to 25% and less than or equal to 45% for light with a wavelength of 350nm.

3. The blank mask according to claim 1, wherein, The surface reflectivity of the light-shielding film for all light with wavelengths greater than or equal to 350 nm and less than or equal to 400 nm is within the range of greater than or equal to 25% and less than or equal to 50%. The reflectivity of the surface of the light-shielding film to all light with wavelengths greater than or equal to 480 nm and less than or equal to 550 nm is in the range of greater than or equal to 30% and less than or equal to 50%.

4. The blank mask according to claim 1, wherein, The Young's modulus of the second light-shielding layer is greater than or equal to 1.0 kPa.

5. The blank mask according to claim 1, wherein, The Young's modulus of the second light-shielding layer is greater than 0.15 times and less than 0.55 times the Young's modulus of the first light-shielding layer.

6. The blank mask according to claim 1, wherein, The absolute value of the value obtained by subtracting the transition metal content of the first light-shielding layer from the transition metal content of the second light-shielding layer is less than or equal to 30 atoms.

7. The blank mask according to claim 1, wherein, The thickness ratio of the first light-shielding layer to the second light-shielding layer is 1:0.02 to 0.

25.

8. A photomask, wherein, include: Transparent substrate, and A light-shielding patterned film is disposed on the light-transmitting substrate; 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 comprises at least one of a transition metal, oxygen, and nitrogen. The upper surface of the light-shielding patterned film has a reflectivity of greater than or equal to 20% and less than or equal to 40% for light with a wavelength of 193nm. The hardness value of the second light-shielding layer is greater than or equal to 0.3 kPa and less than or equal to 0.55 kPa. The hardness value of the second light-shielding layer is more than 0.15 times and less than 0.55 times the hardness value of the first light-shielding layer.

9. A method for manufacturing a semiconductor device, wherein, include: Preparation steps include setting up the light source, photomask, and semiconductor wafer coated with resist film. The exposure step involves selectively transmitting and projecting light incident from the light source onto the semiconductor wafer through the photomask. 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 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 comprises at least one of a transition metal, oxygen, and nitrogen. The upper surface of the light-shielding patterned film has a reflectivity of greater than or equal to 20% and less than or equal to 40% for light with a wavelength of 193nm. The hardness value of the second light-shielding layer is greater than or equal to 0.3 kPa and less than or equal to 0.55 kPa. The hardness value of the second light-shielding layer is more than 0.15 times and less than 0.55 times the hardness value of the first light-shielding layer.

Images