Manufacturing methods for photomasks, photomask preforms, and semiconductor devices

Abstract

This embodiment relates to a photomask, etc. The photomask includes a light-transmitting substrate and a multilayer light-shielding pattern film. The multilayer light-shielding pattern film includes a first light-shielding film and a second light-shielding film. The side surface of the multilayer light-shielding pattern film includes a detection section, and the detection section corresponds to the section between a point spaced apart from the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and a point spaced apart from the lower surface of the second light-shielding film to the upper surface of the second light-shielding film in the side surface of the multilayer light-shielding pattern film. The surface roughness Wr of the detection section satisfies the first formula: 0 < Wr - Wo ≤ 3. In the first formula, Wo is the surface roughness of the detection section before the immersion and cleaning process. Wr is the surface roughness of the detection section after being immersed in SC-1 solution for 800 seconds and cleaned with ozone water. The SC-1 solution is a solution containing NH4OH, H2O2, and H2O. The ozone water is a solution containing 20 ppm ozone using ultrapure water as a solvent.

Description

Technical Field

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

[0002] Due to the high integration of semiconductor devices, there is a need for miniaturization of circuit patterns. This underscores the importance of photolithography, a technique that uses a photomask to develop circuit patterns on the surface of a wafer.

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

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

[0005] A binary photomask has a structure in which a light-shielding pattern layer is formed on a light-transmitting substrate. In a binary photomask, on the side with the pattern, exposure light is transmitted through a transmissive portion (excluding the light-shielding layer) and blocked by a light-shielding portion including the light-shielding layer, thereby exposing the pattern to a resist film on the wafer surface. However, as the pattern of the binary photomask becomes increasingly fine, diffraction of light at the edges of the transmissive portion during the exposure process can cause problems in the development of fine patterns.

[0006] Phase-shifting masks include Levenson type masks, outrigger type masks, and halftone type masks. Halftone type phase-shifting masks have a structure in which a semi-transparent film pattern is formed on a transparent substrate. On the patterned side of the halftone type phase-shifting mask, exposure light is transmitted through a transmissive portion without the semi-transparent layer, and attenuated exposure light is transmitted through a semi-transmissive portion including the semi-transparent layer. There is a phase difference between the attenuated exposure light and the exposure light passing through the transmissive portion. Therefore, diffraction 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] Prior art literature

[0008] Patent documents

[0009] Korean Patent Publication No. 10-2011-0044123

[0010] Japanese Patent No. 6698438

[0011] Japanese Patent No. 5562835 Summary of the Invention

[0012] Technical issues

[0013] The purpose of this embodiment is to provide a photomask blank and a photomask using the same, wherein the photomask blank has strong durability for cleaning processes and excellent optical properties.

[0014] Solutions to the Problem

[0015] According to one embodiment of this specification, a photomask includes: a light-transmitting substrate and a multilayer light-shielding pattern film located on the light-transmitting substrate.

[0016] The aforementioned multilayer light-shielding patterned film includes: a first light-shielding film; and a second light-shielding film disposed on the first light-shielding film and comprising at least one of a transition metal, oxygen, and nitrogen.

[0017] The side surface of the aforementioned multilayer light-shielding pattern film includes a detection zone, which corresponds to the interval between a point spaced apart from a point on the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and a point spaced apart from a point on the lower surface of the second light-shielding film to the upper surface of the second light-shielding film on the side surface of the aforementioned multilayer light-shielding pattern film.

[0018] The side surface of the aforementioned multilayer light-shielding pattern film includes a detection range, which corresponds to the interval between a point on the upper surface of the first light-shielding film at a distance of 5 nm from the lower surface of the first light-shielding film and a point on the lower surface of the second light-shielding film at a distance of 5 nm from the upper surface of the second light-shielding film.

[0019] The surface roughness (Wr) of the above detection range satisfies the conditions of the first equation below.

[0020] [Form 1]

[0021] 0nm <Wr-Wo≤3nm

[0022] In the first formula above, Wo represents the surface roughness (unit: nm) of the detection zone before the soaking and cleaning process.

[0023] The above Wr is the surface roughness (unit: nm) of the above detection range after immersion in standard clean-1 (SC-1) solution for 800 seconds and rinsing with ozone water.

[0024] The above SC-1 solution is a solution containing 14.3% by weight of NH4OH, 14.3% by weight of H2O2 and 71.4% by weight of H2O.

[0025] The ozone water mentioned above is a solution containing 20 ppm (by weight) of ozone, using ultrapure water as a solvent.

[0026] The first light-shielding film and the second light-shielding film can be configured to form an interface.

[0027] The aforementioned detection interval can correspond to the interval between a point 5 nm away from the point on the interface and a point 5 nm away from the point on the interface and a point 5 nm away from the point on the interface and a point on the upper surface of the second light-shielding film.

[0028] The surface roughness (Wr) of the above detection interval can be the largest in the interval corresponding to the above interface.

[0029] The surface roughness (Rz) of the lower surface of the second light-shielding film can be above 4 nm.

[0030] The second light-shielding film may include: an upper light-shielding layer; and an attachment reinforcement layer disposed between the upper light-shielding layer and the first light-shielding layer.

[0031] The aforementioned first light-shielding film may contain transition metals, oxygen, and nitrogen.

[0032] The transition metal content of the aforementioned attachment reinforcement layer may be higher than the transition metal content of the aforementioned first light-shielding film.

[0033] The transition metal content of the aforementioned attachment reinforcement layer may be higher than or equal to the transition metal content of the aforementioned upper light-shielding layer.

[0034] The ratio of the transition metal content of the aforementioned attachment reinforcement layer to the transition metal content of the aforementioned first light-shielding film can be from 1.1 to 2.5.

[0035] The thickness of the aforementioned adhesion reinforcement layer can be to

[0036] The aforementioned first light-shielding film may contain transition metals, oxygen, and nitrogen.

[0037] The aforementioned first light-shielding film may contain 30 atomic% to 60 atomic% of the aforementioned transition metal.

[0038] The sum of the oxygen content and nitrogen content of the first light-shielding film can be from 40 atomic% to 70 atomic%.

[0039] The aforementioned second light-shielding film may contain 50 atomic% to 80 atomic% of the aforementioned transition metal.

[0040] The sum of the oxygen content and nitrogen content of the second light-shielding film can be from 20 atomic% to 50 atomic%.

[0041] The aforementioned transition metals may include at least one of Cr, Ta, Ti, and Hf.

[0042] The Rsk value of the upper surface of the above-mentioned adhesion reinforcement layer after film formation can be below -1.

[0043] The Rku value of the upper surface of the above-mentioned adhesion reinforcement layer after film formation can be 7 or higher.

[0044] The Ra value of the upper surface of the above-mentioned adhesion enhancement layer after film formation can be above 0.5 nm.

[0045] The Rz value of the upper surface of the above-mentioned adhesion enhancement layer after film formation can be above 6 nm.

[0046] According to another embodiment of this specification, the photomask preform includes: a light-transmitting substrate; and a multilayer light-shielding film located on the light-transmitting substrate.

[0047] The aforementioned multilayer light-shielding film includes: a first light-shielding film; and a second light-shielding film disposed on the first light-shielding film and comprising at least one of a transition metal, oxygen, and nitrogen.

[0048] The side surface of the aforementioned multilayer light-shielding film includes a detection zone, which corresponds to the interval between points spaced apart from the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and points spaced apart from the lower surface of the second light-shielding film to the upper surface of the second light-shielding film.

[0049] The side surface of the aforementioned multilayer light-shielding film includes a detection range, which corresponds to the interval between a point 5 nm apart from the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and a point 5 nm apart from the lower surface of the second light-shielding film to the upper surface of the second light-shielding film in the aforementioned multilayer light-shielding film.

[0050] The surface roughness (Wr) of the above detection range satisfies the conditions of the first equation below.

[0051] [Form 1]

[0052] 0nm <Wr-Wo≤3nm

[0053] In the first formula above, Wo represents the surface roughness (unit: nm) of the detection zone before the soaking and cleaning processes.

[0054] The above Wr represents the surface roughness (unit: nm) of the detection area after immersion in SC-1 solution for 800 seconds and rinsing with ozone water.

[0055] The above SC-1 solution is a solution containing 14.3% by weight of NH4OH, 14.3% by weight of H2O2 and 71.4% by weight of H2O.

[0056] The ozone water mentioned above is a solution containing 20 ppm (by weight) of ozone, using ultrapure water as a solvent.

[0057] The first light-shielding film and the second light-shielding film can be configured to form an interface.

[0058] The aforementioned detection interval can correspond to the interval between a point 5 nm away from the point on the interface and a point 5 nm away from the point on the interface and a point 5 nm away from the point on the interface and a point on the upper surface of the second light-shielding film.

[0059] The surface roughness (Wr) of the detection range can be maximized in the range corresponding to the interface described above.

[0060] The surface roughness (Rz) of the lower surface of the second light-shielding film can be above 4 nm.

[0061] The second light-shielding film may include: an upper light-shielding layer; and an attachment reinforcement layer disposed between the upper light-shielding layer and the first light-shielding layer.

[0062] The aforementioned first light-shielding film may contain transition metals, oxygen, and nitrogen.

[0063] The transition metal content of the aforementioned attachment reinforcement layer may be higher than the transition metal content of the aforementioned first light-shielding film.

[0064] The transition metal content of the aforementioned attachment reinforcement layer may be higher than or equal to the transition metal content of the aforementioned upper light-shielding layer.

[0065] The ratio of the transition metal content of the aforementioned attachment reinforcement layer to the transition metal content of the aforementioned first light-shielding film can be from 1.1 to 2.5.

[0066] The thickness of the aforementioned adhesion reinforcement layer can be to

[0067] The aforementioned first light-shielding film may contain transition metals, oxygen, and nitrogen.

[0068] The aforementioned first light-shielding film may contain 30 atomic% to 60 atomic% of the aforementioned transition metal.

[0069] The sum of the oxygen content and nitrogen content of the first light-shielding film can be from 40 atomic% to 70 atomic%.

[0070] The aforementioned second light-shielding film may contain 50 atomic% to 80 atomic% of the aforementioned transition metal.

[0071] The sum of the oxygen content and nitrogen content of the second light-shielding film can be from 20 atomic% to 50 atomic%.

[0072] The aforementioned transition metals may include at least one of Cr, Ta, Ti, and Hf.

[0073] The Rsk value of the upper surface of the above-mentioned adhesion reinforcement layer after film formation can be below -1.

[0074] The Rku value of the upper surface of the above-mentioned adhesion reinforcement layer after film formation can be 7 or higher.

[0075] The Ra value of the upper surface of the above-mentioned adhesion enhancement layer after film formation can be above 0.5 nm.

[0076] The Rz value of the upper surface of the above-mentioned adhesion enhancement layer after film formation can be above 6 nm.

[0077] A method for manufacturing a semiconductor device according to another embodiment of this specification includes: a preparation step, which involves setting up a light source, a photomask, and a semiconductor wafer coated with a resist film; an exposure step, which involves selectively transmitting light incident from the light source onto the semiconductor wafer through the photomask and emitting the light; and a development step, which involves developing a pattern on the semiconductor wafer.

[0078] The aforementioned photomask includes: a light-transmitting substrate; and a multilayer light-shielding pattern film located on the light-transmitting substrate.

[0079] The aforementioned multilayer light-shielding patterned film includes: a first light-shielding film; and a second light-shielding film disposed on the first light-shielding film and comprising at least one of a transition metal, oxygen, and nitrogen.

[0080] The side surface of the aforementioned multilayer light-shielding pattern film includes a detection range, which corresponds to the interval between points spaced 5 nm apart from the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and points spaced 5 nm apart from the lower surface of the second light-shielding film to the upper surface of the second light-shielding film on the side surface of the aforementioned multilayer light-shielding pattern film.

[0081] The surface roughness (Wr) of the above detection range satisfies the conditions of the first equation below.

[0082] [Form 1]

[0083] 0nm <Wr-Wo≤3nm

[0084] In the first formula above, Wo is the surface roughness (in nm) of the detection range MR before the soaking and cleaning process, and Wr is the surface roughness (in nm) of the detection range MR after soaking in SC-1 solution for 800 seconds and cleaning with ozone water. SC-1 solution is a solution containing 14.3 wt% NH4OH, 14.3 wt% H2O2 and 71.4 wt% H2O. Ozone water is a solution containing 20 ppm (by weight) ozone with ultrapure water as solvent.

[0085] A photomask according to another embodiment of this specification includes: a light-transmitting substrate and a multilayer light-shielding pattern film disposed on the light-transmitting substrate; the multilayer light-shielding pattern film includes: a first light-shielding film and a second light-shielding film disposed on the first light-shielding film, and contains at least one of a transition metal, oxygen, and nitrogen; the first light-shielding film contains 35 atomic% to 55 atomic% of the transition metal, the second light-shielding film contains 55 atomic% to 75 atomic% of the transition metal, and the side surface of the multilayer light-shielding pattern film includes a detection region, the detection region corresponding to the interval between points spaced apart from the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and points spaced apart from the lower surface of the second light-shielding film to the upper surface of the second light-shielding film on the side surface of the multilayer light-shielding pattern film, the surface roughness of the detection region satisfying the condition of the following first formula.

[0086] First form:

[0087] 0nm <Wr-Wo≤3nm,

[0088] In the first formula above, Wo is the surface roughness of the detection area before the soaking and cleaning process, and its unit is nm. Wr is the surface roughness of the detection area after soaking in the standard cleaning-1 solution for 800 seconds and cleaning with ozone water, and its unit is nm. The standard cleaning-1 solution is a solution containing 14.3% by weight of NH4OH, 14.3% by weight of H2O2 and 71.4% by weight of H2O. The ozone water is a solution using ultrapure water as a solvent and containing 20 ppm of ozone by weight.

[0089] A photomask preform according to another embodiment of this specification includes: a light-transmitting substrate and a multilayer light-shielding film disposed on the light-transmitting substrate; the multilayer light-shielding film includes: a first light-shielding film and a second light-shielding film disposed on the first light-shielding film, and contains at least one of a transition metal, oxygen, and nitrogen; the first light-shielding film contains 35 atomic% to 55 atomic% of the transition metal, and the second light-shielding film contains 55 atomic% to 75 atomic% of the transition metal; the side surface of the multilayer light-shielding film includes a detection region; the detection region corresponds to the interval between points spaced apart from the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and points spaced apart from the lower surface of the second light-shielding film to the upper surface of the second light-shielding film in the side surface of the multilayer light-shielding film; the surface roughness of the detection region satisfies the condition of the following first formula.

[0090] First form:

[0091] 0nm <Wr-Wo≤3nm,

[0092] In the first formula above, Wo is the surface roughness of the detection area before the soaking and cleaning process, and its unit is nm. Wr is the surface roughness of the detection area after soaking in the standard cleaning-1 solution for 800 seconds and cleaning with ozone water, and its unit is nm. The standard cleaning-1 solution is a solution containing 14.3% by weight of NH4OH, 14.3% by weight of H2O2 and 71.4% by weight of H2O. The ozone water is a solution using ultrapure water as a solvent and containing 20 ppm of ozone by weight.

[0093] A method for manufacturing a semiconductor device according to another embodiment of this specification includes: a preparation step of setting a light source, a photomask, and a semiconductor wafer coated with a resist film; an exposure step of selectively transmitting light incident from the light source onto the semiconductor wafer through the photomask and emitting the light; and a development step of developing a pattern on the semiconductor wafer; wherein the photomask includes a light-transmitting substrate and a multilayer light-shielding pattern film located on the light-transmitting substrate; the multilayer light-shielding pattern film includes a first light-shielding film and a second light-shielding film, wherein the second light-shielding film is disposed on the first light-shielding film and contains a transition gold. The light-shielding film contains at least one of the following: oxygen and nitrogen. The first light-shielding film contains 35 atomic% to 55 atomic% of a transition metal, and the second light-shielding film contains 55 atomic% to 75 atomic% of the aforementioned transition metal. The side surface of the multilayer light-shielding patterned film includes a detection zone. This detection zone corresponds to a region on the side surface of the multilayer light-shielding patterned film between points spaced 5 nm apart from the upper surface to the lower surface of the first light-shielding film and points spaced 5 nm apart from the lower surface to the upper surface of the second light-shielding film. The surface roughness of the detection zone satisfies the condition of the following first formula.

[0094] First form:

[0095] 0nm <Wr-Wo≤3nm,

[0096] In the first formula above, Wo is the surface roughness of the detection area before the soaking and cleaning process, and its unit is nm. Wr is the surface roughness of the detection area after soaking in the standard cleaning-1 solution for 800 seconds and cleaning with ozone water, and its unit is nm. The standard cleaning-1 solution is a solution containing 14.3% by weight of NH4OH, 14.3% by weight of H2O2 and 71.4% by weight of H2O. The ozone water is a solution using ultrapure water as a solvent and containing 20 ppm of ozone by weight.

[0097] The effects of the invention

[0098] The photomask and the like according to this embodiment can have stable durability even during long cleaning processes and exhibit excellent optical properties. Attached Figure Description

[0099] Figure 1 A schematic diagram illustrating a photomask blank according to an embodiment of this specification.

[0100] Figure 2 A schematic diagram illustrating a photomask blank according to another embodiment of this specification.

[0101] Figure 3 for Figure 1 An enlarged view of the portion represented by A in the image.

[0102] Figure 4 for Figure 2 An enlarged view of the portion represented by A'.

[0103] Figure 5 and Figure 6 This is a schematic diagram illustrating a photomask according to another embodiment of this specification.

[0104] Figure 7 and Figure 8 This is a schematic diagram illustrating a photomask according to another embodiment of this specification.

[0105] Figure 9 for Figure 7 An enlarged view of the portion represented by B in the image.

[0106] Figure 10 for Figure 8 An enlarged view of the portion represented by B'.

[0107] Explanation of reference numerals in the attached figures

[0108] 1000: Photomask blank

[0109] 2000: Photomask

[0110] 10: Transparent substrate

[0111] 20: Multi-layer light-blocking film

[0112] 210: First light-blocking film

[0113] 220: Second light-shielding film

[0114] 221: Adhesion Reinforcement Layer

[0115] 222: Upper light-shielding layer

[0116] 230: Other thin films

[0117] 25: Multi-layer light-blocking patterned film

[0118] MR: Detection zone

[0119] i1: The position of the interface between the first and second light-shielding films on the side of the multi-layer light-shielding film or multi-layer light-shielding pattern film.

[0120] i 21 The position of the upper surface of the first light-shielding film on the side of the multi-layer light-shielding film or multi-layer light-shielding patterned film.

[0121] i 22 The position of the lower surface of the second light-shielding film on the side of the multi-layer light-shielding film or multi-layer light-shielding patterned film.

[0122] L1: The interface between the first and second light-shielding films

[0123] L 21 The interface between the first light-shielding film and other films

[0124] L 22 The interface between the second light-shielding film and other films Detailed Implementation

[0125] 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 many different ways and are not limited to the embodiments described herein.

[0126] When inherent manufacturing and material tolerances are present in the meaning of "and", the terms "about" or "substantially" used in this specification are used to express the meaning of their numerical value or close to their numerical value, and are intended to prevent any unreasonable or illegal use by any third party for understanding the accurate or absolute numerical values ​​disclosed in this embodiment.

[0127] Throughout this specification, the term "combination of..." used in the Markush-type description refers to a mixture or combination of one or more components selected from the group of components of the Markush-type description, thereby implying the inclusion of one or more components selected from the aforementioned Markush group.

[0128] Throughout this specification, references in the form of "A and / or B" mean "A or B, or A and B".

[0129] Throughout this specification, unless otherwise specified, terms such as “first,” “second,” or “A,” “B,” etc., are used to distinguish them from each other.

[0130] In this specification, "B is located on A" means that B is located on A, or that B is located on A or may be located on A if there are other layers in between, and should not be interpreted as B being located on the surface of A in contact with it.

[0131] Unless otherwise specified, the use of the singular in this specification is to be interpreted as including the meaning of singular or plural as the context suggests.

[0132] In this instruction manual, room temperature refers to 20°C to 25°C.

[0133] The values ​​of Rsk, Rku, Rq, Ra, and Rz are evaluated according to ISO 4287. However, the surface roughness Rz of the lower surface of the second light-shielding film or the attached reinforcement layer is calculated according to ISO 4287 after the cross-sectional image of the photomask blank or photomask is detected by transmission electron microscopy (TEM) and the lower surface of the second light-shielding film or the attached reinforcement layer is traced from the image.

[0134] The Rsk value represents the degree of skewness (high degree of symmetry) of the surface contour of the detected object.

[0135] The Rku value represents the sharpness (kurtosis) of the surface contour of the detected object.

[0136] The Ra value represents the arithmetic mean height of the surface contour of the object being inspected.

[0137] In the manufacture of semiconductor devices, the process of forming an exposure pattern on a semiconductor wafer is essential. Specifically, a photomask containing the designed pattern is placed on a semiconductor wafer on which a resist layer is formed, and then exposed by a light source. In this process, the resist layer of the semiconductor wafer can be induced to deform, and the resist layer can be treated with a developing solution to form a resist pattern. By repeating the above process, the wiring of the semiconductor device is formed.

[0138] With the increasing integration of semiconductors, there is a need for finer circuit patterns. To form finer patterns on semiconductor wafers, it is recommended to use light with a shorter wavelength than existing exposure light. Examples of exposure light used to form finer patterns include ArF excimer lasers (wavelength 193 nm).

[0139] A cleaning process is essential during the formation of fine patterns on a photomask preform. Examples of cleaning processes include general cleaning and intensive cleaning. General cleaning removes organic matter and other foreign matter generated during the development of fine patterns on the photomask preform's light-shielding film. Intensive cleaning, on the other hand, is performed to precisely control the critical dimension (CD) of the light-shielding film pattern formed on the photomask surface. In particular, intensive cleaning aims to fine-tune the CD of the light-shielding film pattern through a chemical reaction between the pattern and the cleaning solution; therefore, it may require a longer cleaning time compared to general cleaning.

[0140] On the other hand, considering optical and etching properties, the light-shielding film can be formed into a multi-layered structure. During the cleaning process, the light-shielding film may be damaged by the cleaning solution. In particular, for light-shielding films with a multi-layered structure, the area near the interlayer interfaces on the side of the film exposed to the cleaning solution is more susceptible to damage.

[0141] Therefore, the inventors of this embodiment have confirmed through experiments that by using a multilayer structure of light-shielding film that can improve the durability of the light-shielding film to cleaning solutions and by controlling the roughness characteristics of each layer of the light-shielding film, a light-shielding film with stable durability and excellent optical performance can be obtained even after long-term cleaning.

[0142] This embodiment will be described in more detail below.

[0143] Figure 1 A schematic diagram illustrating a photomask blank according to an embodiment of this specification. Figure 2 A schematic diagram illustrating a photomask blank according to another embodiment of this specification. Figure 3 for Figure 1 An enlarged view of the portion represented by A in the image. Figure 4 for Figure 2 An enlarged view of the portion represented by A'. Figure 5 This is a schematic diagram illustrating another embodiment of a photomask according to this specification. Referring to the above... Figures 1 to 5 This implementation method will be described.

[0144] Structure and roughness characteristics of multilayer light-shielding film

[0145] To achieve the above objectives, a photomask blank 1000 according to an embodiment disclosed in this specification includes: a light-transmitting substrate 10, and a multilayer light-shielding film 20 located on the light-transmitting substrate 10.

[0146] The material used for the light-transmitting substrate 10 is not limited to any material that is transparent to exposure light and suitable for use in a photomask. Specifically, the transmittance of the light-transmitting substrate 10 for exposure light with a wavelength of 193 nm can be 85% or more. Alternatively, the transmittance can be 87% or more. Or, the transmittance can be 99.99% or less. For example, a synthetic quartz substrate can be used as the light-transmitting substrate 10. In this case, the light-transmitting substrate 10 can suppress the attenuation of light passing through it.

[0147] In addition, by adjusting the surface characteristics such as flatness and roughness of the light-transmitting substrate 10, the occurrence of optical distortion can be suppressed.

[0148] The multilayer light-shielding film 20 can be located on the front side of the light-transmitting substrate 10.

[0149] The multilayer light-shielding film 20 can block at least a portion of the exposure light incident from the back side of the light-transmitting substrate 10. Furthermore, when other thin films, such as a phase-shifting film 30, are provided between the light-transmitting substrate 10 and the multilayer light-shielding film 20, the multilayer light-shielding film 20 can be used as an etching mask during the etching process of the aforementioned other thin films.

[0150] The photomask preform 1000 has a three-dimensional shape, including a lower surface, an upper surface, and side surfaces, wherein the lower surface and the upper surface face each other. The lower surface is the surface of the light-transmitting substrate 10 in the photomask preform 1000. The upper surface is the thin film side surface of the photomask preform 1000, such as the multilayer light-shielding film 20. The side surfaces of the photomask preform 1000 include the side surfaces of the light-transmitting substrate 10 and the multilayer light-shielding film 20.

[0151] The multilayer light-shielding film 20 includes: a first light-shielding film 210 and a second light-shielding film 220, disposed on the first light-shielding film 210 and containing at least one of a transition metal, oxygen and nitrogen.

[0152] The second light-shielding film 220 can be located on top of and in contact with the first light-shielding film 210. In this case, an interface L1 can be formed between the first light-shielding film 210 and the second light-shielding film 220. That is, the upper surface of the first light-shielding film 210 can be directly in contact with the lower surface of the second light-shielding film 220 to form interface L1 (see...). Figure 1 and Figure 3 ).

[0153] Other thin films may be disposed between the first light-shielding film 210 and the second light-shielding film 220. For example, when the other thin film is located between the first light-shielding film 210 and the second light-shielding film 220 in a manner that is respectively in contact with the first light-shielding film 210 and the second light-shielding film 220, a first interface L can be formed between the first light-shielding film 210 and the other thin film. 21 A second interface L can be formed between the second light-shielding film 220 and other films. 22 (see Figure 2 and Figure 4 In other words, the upper surface of the first light-shielding film 210 can be directly contacted with the lower surface of other films to form the first interface L. 21 Furthermore, the lower surface of the second light-shielding film 220 can be directly contacted with the upper surface of other films to form a second interface L. 22 .

[0154] The side surface of the multilayer light-shielding film 20 includes a detection range MR, corresponding to the interval between points spaced apart from the upper surface of the first light-shielding film 210 to the lower surface of the first light-shielding film and points spaced apart from the lower surface of the second light-shielding film 220 to the upper surface of the second light-shielding film. The side surface of the multilayer light-shielding film 20 also includes a detection range MR, corresponding to the interval between points spaced 5 nm apart from the upper surface of the first light-shielding film 210 to the lower surface of the first light-shielding film and points spaced 5 nm apart from the lower surface of the second light-shielding film 220 to the upper surface of the second light-shielding film. In other words, the side surface of the multilayer light-shielding film 20 includes a detection range MR, corresponding to a point i on the upper surface of the first light-shielding film 210. 21 Points spaced 5 nm apart on the lower surface of the first light-shielding film and point i on the lower surface of the second light-shielding film 220 22 The interval between points spaced 5 nm apart on the upper surface of the second light-shielding film.

[0155] The surface roughness (Wr) of the photomask blank 1000 in the detection interval MR satisfies the following first equation.

[0156] First form:

[0157] 0nm <Wr-Wo≤3nm

[0158] In the first formula above, Wo is the surface roughness (unit: nm) of the detection range MR before the soaking and cleaning process.

[0159] The above Wr represents the surface roughness (unit: nm) of the above detection range MR after immersion in standard clean-1 (SC-1) solution for 800 seconds and rinsing with ozone water.

[0160] The above SC-1 solution is a solution containing 14.3% by weight of NH4OH, 14.3% by weight of H2O2 and 71.4% by weight of H2O.

[0161] The ozone water mentioned above is a solution containing 20 ppm (by weight) of ozone, using ultrapure water as a solvent.

[0162] After the patterning process of a thin film such as a light-shielding film, a cleaning process can be performed to remove particles and other contaminants remaining on the pattern. Specifically, a cleaning solution such as the SC-1 solution described above can be used to remove foreign matter from the pattern, and an ozone water rinsing process is performed. The cleaning solution and ozone water are highly reactive with the materials constituting the pattern, and therefore may damage the pattern during the cleaning and rinsing processes. In particular, in an enhanced cleaning process used for controlling pattern linewidth, the pattern is exposed to the cleaning solution for a longer period than in a normal cleaning process, and therefore the damage to the pattern may be relatively greater.

[0163] In particular, regarding multilayer light-shielding films, the layers contained within the film can contact each other to form a multilayer structure, and these layers can have different compositions. Due to the different compositions, adjacent layers may not have sufficient adhesion. Therefore, during the cleaning process, the sides of the multilayer light-shielding film 20 exposed to the cleaning solution may experience relatively greater damage near the interfaces between adjacent layers. Due to this damage, the shape of a portion of the sides of the multilayer light-shielding film 20 may become deformed, or a portion of the multilayer light-shielding film 20 may detach. In this case, since the pattern cannot have the desired shape, the resolution of the photomask may decrease when developing the pattern on the wafer surface.

[0164] One technical feature of this invention is that the resolution reduction of the photomask 2000 caused by the cleaning process is suppressed by limiting the difference in roughness values ​​of the photomask blank 1000 before and after cleaning under preset conditions.

[0165] The following section will describe the detection method for the surface roughness Wr and Wo in the detection range MR of the photomask blank 1000.

[0166] The detection range MR is the range determined from the transmission electron microscope (TEM) image of the photomask blank 1000. The surface roughness values ​​Wr and Wo are values ​​detected from the TEM image of the photomask blank 1000. However, determining the detection range MR and detecting the Wr and Wo values ​​can be performed not only by TEM, but also by other devices capable of detecting cross-sectional images of the photomask blank 1000.

[0167] The aforementioned detection interval MR refers to the interval between points spaced apart from the upper surface of the first light-shielding film 210 toward the lower surface of the first light-shielding film 210 and points spaced apart from the lower surface of the second light-shielding film 220 toward the upper surface of the second light-shielding film 220 when observing the side surface of the photomask blank 1000 (see [reference]). Figure 4 ).

[0168] The aforementioned detection interval MR refers to the interval between points spaced 5 nm apart from the upper surface of the first light-shielding film 210 toward the lower surface of the first light-shielding film 210 and points spaced 5 nm apart from the lower surface of the second light-shielding film 220 toward the upper surface of the second light-shielding film 220 when observing the side surface of the photomask blank 1000.

[0169] The first and second light-shielding films can be configured to form an interface therebetween. When the first light-shielding film 210 and the second light-shielding film 220 are configured to be in contact with each other, an interface can be formed on the surfaces where the first light-shielding film 210 and the second light-shielding film 220 are in contact. The interval between a point i1 on the interface and a point 5 nm away from the upper surface of the photomask blank 1000 or the photomask 2000, and a point 5 nm away from the lower surface of the photomask blank 1000 or the photomask 2000, is defined as the detection interval MR. When the distance from the point i1 to the point 5 nm away from the upper or lower surface exceeds the side portion of the multilayer light-shielding film 20, the interval up to the upper or lower limit of the side portion of the multilayer light-shielding film 20 or the multilayer light-shielding pattern film 25 is defined as the detection interval MR (see [link to relevant documentation]). Figure 3 ).

[0170] When another thin film 230 is provided between the first light-shielding film 210 and the second light-shielding film 220, an interface can be formed between the first light-shielding film 210 and the other thin film 230, and an interface can also be formed between the second light-shielding film 220 and the other thin film 230. From the first point i 21 Points spaced 5 nm apart on the lower surface of the first light-shielding film 210 and from the second point i 22The interval between points spaced 5 nm apart on the upper surface of the second light-shielding film 220 is defined as the detection interval MR, wherein the aforementioned first point i 21 Located at the interface formed between the first light-shielding film 210 and other films 230, and the aforementioned second point i 22 Located at the interface formed between the second light-shielding film 220 and other films 230. From the aforementioned first point i 21 When the points on the lower surface of the aforementioned multilayer light-shielding film 20 or multilayer light-shielding pattern film 25 extend beyond the side surface at a distance of 5 nm, the interval up to the lower limit of the side surface region of the multilayer light-shielding film 20 or multilayer light-shielding pattern film 25 is defined as the detection interval MR. When from the aforementioned second point i... 22 When the points on the upper surface are spaced 5 nm apart and extend beyond the side of the multilayer light-shielding film 20 or the multilayer light-shielding pattern film 25, the interval up to the upper limit line of the side area of ​​the multilayer light-shielding film 20 or the multilayer light-shielding pattern film 25 is defined as the detection interval MR (see [reference]). Figure 4 ).

[0171] The methods for detecting surface roughness Wr and Wo are as follows.

[0172] Before the cleaning process, a cross-sectional image of the side of the photomask preform 1000 is examined using a transmission electron microscope (TEM). Specifically, the photomask preform 1000 is machined to a size of 15 mm in width and 15 mm in length, and then the surface of the machined photomask preform is treated with a focused ion beam (FIB) to prepare a test piece. The TEM image of the test piece is then examined using a TEM inspection device. For example, a JEM-2100F HR model manufactured by JEOL Ltd. can be used to inspect the TEM image of the test piece.

[0173] The profile corresponding to the MR detection region is traced on the side of the multilayer light-shielding film 20 or the multilayer light-shielding pattern film 25 from the TEM image described above. The Wo value is calculated from the traced line according to the Ry calculation method of ISO 4287. The unit of the Wo value is nm.

[0174] Except for the step of immersing the photomask blank 1000 or the photomask in SC-1 solution and then cleaning it with ozone water before testing, the calculation method for the Wr value is the same as that for the Wo value. The unit of the Wr value is nm.

[0175] When testing the Wr value, the photomask blank 1000, which is the object of testing, is immersed in the SC-1 solution, so that the multilayer light-shielding film 20 is completely submerged. After immersing the photomask blank in the SC-1 solution for 800 seconds, it is cleaned with ozone water. The cleaning with ozone water is sufficient to remove the SC-1 solution from the multilayer light-shielding film 20. The immersion in the SC-1 solution and the cleaning with ozone water are carried out at room temperature.

[0176] The Wr and Wo values ​​are detected within the same detection interval.

[0177] The value obtained by subtracting the Wr value from the Wo value refers to the degree to which the side of the multilayer light-shielding film 20 is eroded inward toward the photomask blank 1000 after the soaking and cleaning process, based on the side profile of the multilayer light-shielding film 20 before the soaking and cleaning process.

[0178] In other words, if we define the imaginary line extending along the side of the photomask blank 1000 in the thickness direction as the reference line, then the value obtained by subtracting the Wo value from the Wr value refers to the degree to which the side of the multilayer light-shielding film 20 is eroded inward toward the photomask blank 1000 due to the soaking and cleaning process.

[0179] The surface roughness Wr of the photomask blank 1000 in the detection interval MR of this embodiment can satisfy the conditions of the first equation below.

[0180] First Form

[0181] 0nm <Wr-Wo≤3nm

[0182] In the first formula above, Wo is the surface roughness (unit: nm) of the detection range MR before the soaking and cleaning process, and Wr is the surface roughness (unit: nm) of the detection range MR after soaking in SC-1 solution for 800 seconds and cleaning with ozone water.

[0183] The above-mentioned SC-1 solution is a solution containing 14.3% by weight of NH4OH, 14.3% by weight of H2O2 and 71.4% by weight of H2O. The above-mentioned ozone water is a solution containing 20 ppm (by weight) of ozone using ultrapure water as a solvent.

[0184] In this case, the photomask preform 1000 has improved durability against cleaning and rinsing solutions, thus suppressing the reduction in photomask resolution caused by cleaning.

[0185] The surface roughness Rz of the lower surface of the second light-shielding film 220 can be above 4 nm.

[0186] The second light-shielding film 220 can be formed by sputtering the surface to which the second light-shielding film 220 is to be formed. In this case, the second light-shielding film 220 can be formed in contact with the surface to which the film is to be formed. Factors affecting the surface roughness Wr value of the detection range MR of the photomask blank 1000 include: the adhesion between the second light-shielding film 220 and the surface to which the film is to be formed; the compositional difference between the second light-shielding film and the surface to which the film is to be formed; and the voltage applied to the target when sputtering the second light-shielding film.

[0187] In particular, the inventors of this embodiment have experimentally confirmed that the cleaning durability of the multilayer light-shielding film 20 varies depending on the surface roughness of the lower surface of the second light-shielding film 220. This is believed to be because the adhesion between the second light-shielding film 220 and the film-forming target surface varies depending on the contact area between the second light-shielding film 220 and the film-forming target surface. A technical feature of the photomask preform 1000 implemented with this in mind is that by controlling the surface roughness of the lower surface of the second light-shielding film 220, the adhesion between the second light-shielding film 220 and the film-forming target surface is improved, thereby improving the cleaning durability of the multilayer light-shielding film 20 and making the multilayer light-shielding film 20 exhibit relatively uniform optical properties in the in-plane direction.

[0188] The method for detecting the surface roughness Rz value of the lower surface of the second light-shielding film 220 is as follows.

[0189] A cross-sectional image of the multilayer light-shielding film of the photomask blank 1000, which is the object of inspection, is obtained by TEM inspection. Then, the interface between the second light-shielding film 220 and the film-forming object surface is traced from the inspected image, and the Rz value of the lower surface of the second light-shielding film 220 is calculated based on the Rz value calculation method standardized in ISO 4287 using the traced line.

[0190] The method for detecting the TEM image of the multilayer light-shielding film 20 of the photomask blank 1000 during the detection of the Rz value of the lower surface of the second light-shielding film 220 is the same as the method for detecting the TEM image during the detection of the Wr and Wo values ​​of the multilayer light-shielding film 20.

[0191] In the photomask blank 1000 or photomask used as the detection object, when the second light-shielding film 220 is formed to be in contact with the first light-shielding film 210, the lower surface of the second light-shielding film 220 can be in contact with the upper surface of the first light-shielding film 210 to form interface L1 (see...). Figure 3 For ease of explanation, the lower surface of the second light-shielding film 220 is defined as the interface L1 between the second light-shielding film 220 and the first light-shielding film 210. When another thin film 230 is provided between the second light-shielding film 220 and the first light-shielding film 210, the lower surface of the second light-shielding film 220 can be in contact with the upper surface of the other thin film 230 to form interface L1. 22 (see Figure 4For ease of explanation, the lower surface of the second light-shielding film 220 is defined as the interface L between the second light-shielding film 220 and the other films 230 mentioned above. 22 .

[0192] The surface roughness Rz of the lower surface of the second light-shielding film 220 can be 4 nm or more. Alternatively, Rz can be 6 nm or more. Or, Rz can be 20 nm or less. Or, Rz can be 10 nm or less. In this case, the photomask blank 1000 not only has stable durability in the cleaning process, but also allows the multilayer light-shielding film 20 to have relatively uniform optical properties in the in-plane direction.

[0193] Adhesion reinforcement layer

[0194] The second light-shielding film 220 may include an upper light-shielding layer 222 and an adhesion enhancement layer 221.

[0195] The attachment reinforcement layer 221 can be located between the upper light-shielding layer 222 and the first light-shielding film 210.

[0196] The second light-shielding film 220 can be formed by sputtering. The second light-shielding film 220 can be formed by sputtering a film-forming surface, which is the surface of a thin film disposed in contact with the lower surface of the second light-shielding film 220. The roughness value of the interface formed between the second light-shielding film 220 and the thin film can vary depending on the surface roughness value of the film-forming surface before the formation of the second light-shielding film 220, which is the thin film disposed in contact with the lower surface of the second light-shielding film 220.

[0197] This embodiment utilizes an adhesion enhancement layer 221 with controlled roughness, composition, and layer thickness as one method to improve cleanability. The aforementioned adhesion enhancement layer can provide a photomask preform 1000 with improved durability and CD characteristics by increasing the adhesion between the second light-shielding film 220 and the thin film, wherein the thin film is disposed in contact with the lower surface of the second light-shielding film 220.

[0198] The attachment reinforcement layer 221 and the first light-shielding film 210 are connected to form interface L3 (see Figure 5Specifically, the lower surface of the adhesion enhancement layer 221 and the upper surface of the first light-shielding film 210 are in contact, forming an interface L3. For ease of explanation, the lower surface of the adhesion enhancement layer 221 is defined as the interface L3 between the adhesion enhancement layer 221 and the first light-shielding film 210. The roughness Rz of the lower surface L3 of the adhesion enhancement layer 221 can be 4 nm or more. Alternatively, Rz can be 6 nm or more. Or, Rz can be 20 nm or less. Or, Rz can be 10 nm or less. In this case, the washability of the side portion of the multilayer light-shielding film 20 is improved, and changes in the optical properties of the multilayer light-shielding film in the in-plane direction can be effectively suppressed.

[0199] The roughness detection method for the lower surface L3 of the attachment reinforcement layer 221 is the same as the roughness detection method for the lower surface of the second light-shielding film.

[0200] The first light-shielding film 210 contains a transition metal, oxygen, and nitrogen. The second light-shielding film 220 may contain a transition metal, oxygen, or nitrogen. The composition of the first light-shielding film 210 and the second light-shielding film 220 is repeated below and will therefore be omitted.

[0201] The transition metal content of the attachment reinforcement layer 221 can be higher than that of the first light-shielding film 210. The transition metal content of the attachment reinforcement layer 221 can be higher than or equal to that of the upper light-shielding layer 222. It may be difficult to substantially distinguish the boundary between the attachment reinforcement layer 221 and the upper light-shielding layer 222.

[0202] The surface roughness value and the roughness value of the lower surface of the formed adhesion enhancement layer 221 vary depending on factors such as the composition of the adhesion enhancement layer 221, the film thickness, the composition of the atmosphere gas injected into the chamber during sputtering, and the electric current applied to the sputtering target. In particular, in this embodiment, when forming the adhesion enhancement layer 221, the content ratio of active gas in the atmosphere gas injected into the sputtering chamber is set to be relatively lower than the range of active gas content ratio in the atmosphere gas injected into the sputtering chamber when forming the first light-shielding film 210, thereby controlling the transition metal content of the adhesion enhancement layer 221. As a result, the in-plane optical properties of the multilayer light-shielding film can be controlled within a certain range, and the adhesion between the second light-shielding film 220 and the thin film, which is disposed in contact with the lower surface of the second light-shielding film 220, can be improved.

[0203] When the first light-shielding film 210 is in contact with the second light-shielding film 220, the thin film disposed in contact with the lower surface of the second light-shielding film 220 is equivalent to the first light-shielding film 210 (see...). Figure 3 When another film 230 is provided between the first light-shielding film 210 and the second light-shielding film 220, the film disposed in contact with the lower surface of the second light-shielding film 220 is equivalent to the other film 230 (see...). Figure 4 ).

[0204] The ratio of the transition metal content of the adhesion enhancement layer 221 to the transition metal content of the first light-shielding film 210 can be from 1.1 to 2.5. The ratio of the transition metal content of the adhesion enhancement layer 221 to the transition metal content of the first light-shielding film 210 can be from 1.3 to 2.3. The ratio of the transition metal content of the adhesion enhancement layer 221 to the transition metal content of the first light-shielding film 210 can be from 1.5 to 2.25. In this case, it is easier to induce a relatively high surface roughness value in the adhesion enhancement layer 221. Furthermore, it helps to suppress particle formation caused by unevenness formed on the surface of the adhesion enhancement layer 221 during the exposure process.

[0205] The method for detecting the content of each element in the attachment reinforcement layer 221 is the same as the following content, so the description will be omitted.

[0206] The thickness of the adhesion reinforcement layer 221 can be to

[0207] The surface roughness value of the adhesion reinforcement layer 221 and the lower surface roughness value of the adhesion reinforcement layer 221 are affected by the film thickness of the adhesion reinforcement layer 221.

[0208] The adhesion enhancement layer 221 can be formed by sputtering. Specifically, the adhesion enhancement layer 221 can be formed by depositing sputtered particles (e.g., argon ions) onto the surface of the film-forming object through collisions with the target. During sputtering, the deposited sputtered particles are scattered on the deposition object to create spaces between them, which can be controlled to achieve a roughness of a certain magnitude on the surface of the film. As sputtering continues, the spaces between the particles are filled with newly deposited sputtered particles, and thus the roughness may gradually decrease.

[0209] This embodiment can provide an adhesion enhancement layer 221 with a specific range of film thickness, surface roughness, etc., by means of sputtering or the like, to a degree of roughness with a preset level.

[0210] The details regarding the sputtering time of the attachment reinforcement layer 221 are repeated in the following description of the preparation method, and therefore will be omitted.

[0211] The thickness of the attached reinforcement layer 221 can be measured by TEM image detection.

[0212] The thickness of the adhesion reinforcement layer 221 can be to The thickness of the adhesion reinforcement layer 221 can be to The thickness of the adhesion reinforcement layer 221 can be to In this case, the multilayer light-shielding film 20 can suppress damage caused by the cleaning solution, while reducing the amount of particles generated during exposure.

[0213] Composition and thickness of multilayer light-shielding film

[0214] When patterning the multilayer light-shielding film 20, dry etching can be applied. In this case, compared to the first light-shielding film 210, the second light-shielding film 220 is exposed to the etchant for a relatively longer time during the patterning process. Assuming that the etching characteristics of the second light-shielding film 220 are similar to those of the first light-shielding film 210, the patterned linewidth of the multilayer light-shielding film 20 after patterning can gradually increase downwards. This may become one of the factors that reduce the photomask resolution. To suppress this situation, process conditions such as the composition of each film, sputtering voltage, atmospheric gas, and the thickness of each film contained in the multilayer light-shielding film can be controlled so that the second light-shielding film 220 has relatively lower etching characteristics compared to the first light-shielding film 210 under the same etching conditions. In this case, the side surface of the patterned multilayer light-shielding film can be formed to be relatively closer to perpendicular to the surface of the light-transmitting substrate. In particular, this embodiment can improve the shape controllability of the patterned multilayer light-shielding film 20 by adjusting the composition and film thickness of each light-shielding film.

[0215] The first light-shielding film 210 may contain a transition metal, oxygen, and nitrogen. The first light-shielding film 210 may contain 30 atomic% (at%) to 60 atomic% of the transition metal. The first light-shielding film 210 may contain 35 atomic% to 55 atomic% of the transition metal. The first light-shielding film 210 may contain 38 atomic% to 45 atomic% of the transition metal.

[0216] The total oxygen and nitrogen content of the first light-shielding film 210 can be from 40 atomic% to 70 atomic%. The total oxygen and nitrogen content of the first light-shielding film 210 can be from 45 atomic% to 65 atomic%. The total oxygen and nitrogen content of the first light-shielding film 210 can be from 50 atomic% to 60 atomic.

[0217] The first light-shielding film 210 may contain 20 atomic% to 35 atomic% oxygen. The first light-shielding film 210 may contain 23 atomic% to 33 atomic% oxygen. The first light-shielding film 210 may contain 25 atomic% to 30 atomic% oxygen.

[0218] The first light-shielding film 210 may contain 20 atomic% to 35 atomic% of nitrogen. The first light-shielding film 210 may contain 23 atomic% to 33 atomic% of nitrogen. The first light-shielding film 210 may contain 25 atomic% to 30 atomic% of nitrogen.

[0219] In this case, the first light-shielding film 210 can help give the multilayer light-shielding film 20 excellent light-absorbing properties. In addition, when the multilayer light-shielding film 20 is patterned, the occurrence of steps that may appear on the sides of the patterned light-shielding film can be suppressed.

[0220] The second light-shielding film 220 may contain transition metals, oxygen, and nitrogen. The second light-shielding film 220 may contain 50 atomic% to 80 atomic% of transition metals. The second light-shielding film 220 may contain 55 atomic% to 75 atomic% of transition metals. The second light-shielding film 220 may contain 60 atomic% to 70 atomic% of transition metals.

[0221] The total oxygen and nitrogen content of the second light-shielding film 220 can be from 20 atomic% to 50 atomic%. The total oxygen and nitrogen content of the second light-shielding film 220 can be from 25 atomic% to 45 atomic%. The total oxygen and nitrogen content of the second light-shielding film 220 can be from 30 atomic% to 40 atomic.

[0222] The second light-shielding film 220 may contain 20 atomic% to 50 atomic% of nitrogen. The second light-shielding film 220 may contain 25 atomic% to 45 atomic% of nitrogen. The second light-shielding film 220 may contain 30 atomic% to 40 atomic% of nitrogen.

[0223] In these cases, the second light-shielding film 220 can help give the multilayer light-shielding film 20 excellent light-extinguishing properties. Furthermore, even if the upper part of the patterned multilayer light-shielding film is exposed to etching gas for a long time, the linewidth in the thickness direction of the multilayer light-shielding patterned film can remain relatively constant.

[0224] The aforementioned transition metals may include at least one of Cr, Ta, Ti, and Hf. Cr may be one of the aforementioned transition metals.

[0225] The content of each element in each film and layer of the multilayer light-shielding film 20 was detected by X-ray photoelectron spectroscopy (XPS). Specifically, a sample was prepared by processing a photomask preform to a size of 15 mm in width and 15 mm in length. Then, the sample was placed in an XPS detection device, and a region with a width of 4 mm and a length of 2 mm located at the center of the sample was etched to detect the content of each element in each film and layer of the multilayer light-shielding film 20.

[0226] For example, the content of each element in each film and layer of the multilayer light-shielding film 20 can be detected using a K-α type manufactured by Thermo Scientific.

[0227] The thickness of the first light-shielding film 210 can be to The thickness of the first light-shielding film 210 can be to The thickness of the first light-shielding film 210 can be to In this case, the first light-blocking film 210 can help the multilayer light-blocking film 20 effectively block the exposure light.

[0228] The thickness of the second light-shielding film 220 can be to The thickness of the second light-shielding film 220 can be to The thickness of the second light-shielding film 220 can be to In this case, the second light-shielding film 220 can help improve the light-shielding properties of the multilayer light-shielding film 20 and suppress linewidth variations in the thickness direction of the multilayer light-shielding pattern film.

[0229] The ratio of the thickness of the second light-shielding film 220 to the thickness of the first light-shielding film 210 can be 0.05 to 0.3. The aforementioned thickness ratio can be 0.07 to 0.25. The aforementioned thickness ratio can be 0.1 to 0.2. In this case, the multilayer light-shielding film 20 can have sufficient light-absorbing properties. Furthermore, the side surfaces of the patterned multilayer light-shielding film can be formed approximately perpendicular to the light-transmitting substrate.

[0230] The ratio of the thickness of the attachment reinforcement layer 221 to the thickness of the first light-shielding film 210 can be 0.005 to 0.05. The ratio of the thickness of the attachment reinforcement layer 221 to the thickness of the first light-shielding film 210 can be 0.01 to 0.04. The ratio of the thickness of the attachment reinforcement layer 221 to the thickness of the first light-shielding film 210 can be 0.015 to 0.03. In this case, the multilayer light-shielding film can have stable durability against cleaning solutions.

[0231] Optical properties of multilayer light-shielding films

[0232] The multilayer light-shielding film 20 can have an optical density of 1.8 or higher for light with a wavelength of 193 nm. The multilayer light-shielding film 20 can have an optical density of 1.9 or higher for light with a wavelength of 193 nm.

[0233] The multilayer light-shielding film 20 can have a transmittance of less than 1.5% for light with a wavelength of 193nm. The multilayer light-shielding film 20 can have a transmittance of less than 1.4% for light with a wavelength of 193nm. The multilayer light-shielding film 20 can have a transmittance of less than 1.2% for light with a wavelength of 193nm.

[0234] In this case, the pattern of the multi-layered light-blocking film 20 can effectively block the transmission of exposed light.

[0235] A phase-shifting film may be provided between the light-transmitting substrate 10 and the multilayer light-shielding film 20. The film including the phase-shifting film and the multilayer light-shielding film 20 can have an optical density of 3 or higher for light with a wavelength of 193 nm. Alternatively, the film including the phase-shifting film and the multilayer light-shielding film 20 can have an optical density of 3.2 or higher for light with a wavelength of 193 nm. In this case, the aforementioned film can effectively suppress the transmission of exposure light.

[0236] Figure 6 This is a schematic diagram illustrating a photomask preform according to another embodiment of this specification. In the following text, reference will be made to the above... Figure 6 Please provide an explanation.

[0237] Other films

[0238] As other thin films, it can be used for phase shift films 30, hard mask films (not shown in the figure), etc.

[0239] The phase-shifting film 30 is a thin film that attenuates the light intensity of the exposure light transmitted through the phase-shifting film and substantially suppresses the diffraction light generated at the edge of the transfer pattern by adjusting the phase difference.

[0240] The phase-shifting film 30 can have a phase difference of 170° to 190° for light with a wavelength of 193 nm. The phase-shifting film 30 can have a phase difference of 175° to 185° for light with a wavelength of 193 nm. The phase-shifting film 30 can have a transmittance of 3% to 10% for light with a wavelength of 193 nm. The phase-shifting film 30 can have a transmittance of 4% to 8% for light with a wavelength of 193 nm. In this case, the resolution of the photomask including the aforementioned phase-shifting film 30 can be improved.

[0241] The phase-shifting film 30 may contain a transition metal and silicon. The phase-shifting film 30 may contain a transition metal, silicon, oxygen, and nitrogen. The aforementioned transition metal may be molybdenum.

[0242] A hard mask can be located on the multilayer light-shielding film 20. The hard mask can improve adhesion to the resist film to suppress resist film collapse during pattern etching, and can be used as an etching mask film during pattern etching of the multilayer light-shielding film 20.

[0243] Hard masks can include silicon, nitrogen, and oxygen.

[0244] Figure 7 and Figure 8 This is a schematic diagram illustrating a photomask according to another embodiment of this specification. Figure 9 for Figure 7 An enlarged view of the portion represented by B in the image. Figure 10 for Figure 8 An enlarged view of the portion represented by B'. Refer to the following text. Figures 7 to 10 Please provide an explanation.

[0245] Photomask

[0246] According to another embodiment of this specification, a photomask 2000 includes: a light-transmitting substrate 10; and a multilayer light-shielding pattern film 25 located on the light-transmitting substrate 10.

[0247] The multilayer light-shielding patterned film 25 includes a first light-shielding film 210 and a second light-shielding film 220 disposed on the first light-shielding film 210, and contains at least one of a transition metal, oxygen and nitrogen.

[0248] The side surface of the multilayer light-shielding pattern film 25 includes a detection zone, which corresponds to the interval between points spaced apart from the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and points spaced apart from the lower surface of the second light-shielding film to the upper surface of the second light-shielding film.

[0249] The surface roughness (Wr) of the above detection interval MR satisfies the conditions of the first equation below.

[0250] First Form

[0251] 0nm <Wr-Wo≤3nm

[0252] In the first formula above, Wo is the surface roughness (unit: nm) of the detection range MR before the soaking and cleaning process.

[0253] The above Wr represents the surface roughness (unit: nm) of the above detection range MR after immersion in SC-1 solution for 800 seconds and rinsing with ozone water.

[0254] The above SC-1 solution is a solution containing 14.3% by weight of NH4OH, 14.3% by weight of H2O2 and 71.4% by weight of H2O.

[0255] The ozone water mentioned above is a solution containing 20 ppm (by weight) of ozone, using ultrapure water as a solvent.

[0256] The side surface of the aforementioned multilayer light-shielding pattern film includes a detection zone, which corresponds to the interval between a point on the upper surface of the first light-shielding film at a distance of 5 nm from the lower surface of the first light-shielding film and a point on the lower surface of the second light-shielding film at a distance of 5 nm from the upper surface of the second light-shielding film.

[0257] The description of the structure, roughness characteristics, composition, and film thickness of the multilayer light-shielding patterned film 25 is the same as the description of the photomask blank 1000 above, so it will be omitted.

[0258] The photomask 2000 can be prepared by patterning the photomask blank 1000.

[0259] Preparation method of multilayer light-shielding film

[0260] A method for preparing a photomask blank 1000 according to an embodiment of this specification includes: a preparation step, in which a sputtering target containing a transition metal and a light-transmitting substrate 10 are disposed in a sputtering chamber; and a multilayer light-shielding film 20 forming step, in which an atmospheric gas is injected into the sputtering chamber, an electric current is applied to the sputtering target, and a multilayer light-shielding film 20 is formed on the light-transmitting substrate 10.

[0261] The multilayer light-shielding film 20 forming process includes: a first light-shielding film 210 forming process, forming a first light-shielding film 210 on a light-transmitting substrate 10; an attachment reinforcement layer 221 forming process, forming an attachment reinforcement layer 221 on the formed first light-shielding film 210; and a second light-shielding film 220 forming process, forming an upper reinforcement layer 222 on the aforementioned attachment reinforcement layer 221.

[0262] In the preparation step, the composition of the multilayer light-shielding film 20 can be considered when selecting the target for forming the multilayer light-shielding film 20. As a sputtering target, a target containing a transition metal can be used. Two or more targets can be used, one of which contains a transition metal. The target containing a transition metal can contain more than 90 atomic percent of transition metal. The target containing a transition metal can contain more than 95 atomic percent of transition metal. The target containing a transition metal can contain 99 atomic percent of transition metal.

[0263] Transition metals may include at least one of Cr, Ta, Ti, and Hf. Cr may be a transition metal.

[0264] The contents of the light-transmitting substrate 10 set in the sputtering chamber are the same as those described above, so the description will be omitted.

[0265] In the film formation step of the multilayer light-shielding film 20, different film formation process conditions can be used when forming each film and each layer included in the multilayer light-shielding film 20. In particular, considering the surface roughness characteristics, chemical resistance, matting characteristics, and etching characteristics of each film or layer, different conditions can be used, such as atmospheric gas composition, chamber pressure, electric current applied to the sputtering target, film formation time, and substrate rotation speed.

[0266] The atmosphere gas can include inert gases, reactive gases, and sputtering gases. An inert gas is a gas that does not contain the elements constituting the thin film to be formed. A reactive gas is a gas that contains the elements constituting the thin film to be formed. A sputtering gas is a gas ionized in a plasma atmosphere and colliding with a target. Inert gases can include helium (He). Reactive gases can include nitrogen-containing gases. For example, the nitrogen-containing gases mentioned above can be N2, NO, NO2, N2O, N2O3, N2O4, N2O5, etc. Reactive gases can include oxygen-containing gases. For example, the oxygen-containing gases mentioned above can be O2, CO2, etc. Reactive gases can include both nitrogen-containing and oxygen-containing gases. The reactive gases mentioned above can include gases containing both nitrogen and oxygen. For example, the gases containing both nitrogen and oxygen mentioned above can be NO, NO2, N2O, N2O3, N2O4, N2O5, etc.

[0267] The sputtering gas can be argon (Ar).

[0268] As a power source to apply power to the sputtering target, a DC power supply or an RF power supply can be used.

[0269] During the formation of the first light-shielding film 210, the power applied to the sputtering target can be from 1.5 kW to 2.5 kW. Alternatively, the power applied to the sputtering target can be from 1.6 kW to 2 kW. In this case, it can help to ensure the stable durability of the multilayer light-shielding film 20.

[0270] During the formation of the first light-shielding film 210, the ratio of the flow rate of the reactive gas to the flow rate of the inactive gas in the atmosphere can be 1.5 to 3. The aforementioned flow rate ratio can be 1.8 to 2.7. The aforementioned flow rate ratio can be 2 to 2.5.

[0271] In the reaction gas, the ratio of oxygen content to nitrogen content can be between 1.5 and 4. In the reaction gas, the ratio of oxygen content to nitrogen content can be between 2 and 3. In the reaction gas, the ratio of oxygen content to nitrogen content can be between 2.2 and 2.7.

[0272] In this case, it can help to make the multilayer light-shielding film 20 have sufficient light-absorbing properties. In addition, it can help the sides of the multilayer light-shielding film 20 have a shape that is close to perpendicular to the light-transmitting substrate 10. The multilayer light-shielding film 20 is a light-shielding film patterned by controlling the etching characteristics of the first light-shielding film 210.

[0273] The film-forming time of the first light-shielding film 210 can be from 200 seconds to 300 seconds. Alternatively, the film-forming time of the first light-shielding film 210 can be from 210 seconds to 240 seconds. In this case, it can help to give the multilayer light-shielding film 20 sufficient light-absorbing properties.

[0274] During the film formation process of the adhesion reinforcement layer 221, the adhesion reinforcement layer 221 can be formed in a manner that is in contact with the surface of the first light-shielding film 210. The adhesion reinforcement layer 221 can also be formed in a manner that is in contact with the surface of other thin films located on the first light-shielding film 210.

[0275] During the deposition of the adhesion reinforcement layer 221, the power applied to the sputtering target can be from 1.5 kW to 2.5 kW. Alternatively, the power applied to the sputtering target can be from 1.6 kW to 2 kW. In this case, the surface roughness of the adhesion reinforcement layer 221 and the roughness value of the lower surface of the adhesion reinforcement layer can be controlled within a preset range, thereby contributing to the excellent durability of the multilayer light-shielding film 20 during the cleaning process.

[0276] During the deposition of the adhesion reinforcement layer 221, an electric current can be applied to the sputtering target at least 15 seconds after the thin film, such as the first light-shielding film, is formed and adhering to the lower surface of the adhesion reinforcement layer 221. Alternatively, an electric current can be applied to the sputtering target at least 20 seconds after the thin film is formed and adhering to the lower surface of the adhesion reinforcement layer 221. Or, an electric current can be applied to the sputtering target within 30 seconds after the thin film is formed and adhering to the lower surface of the adhesion reinforcement layer 221. In these cases, the adhesion reinforcement layer 221 can help to give the multilayer light-shielding film superior washability.

[0277] During the film formation process of the reinforcement layer 221, the ratio of the flow rate of the reactive gas to the flow rate of the inactive gas in the atmosphere can be 0.2 to 0.8. The aforementioned flow rate ratio can be 0.3 to 0.7. The aforementioned flow rate ratio can be 0.35 to 0.6.

[0278] In the reaction gas, the ratio of oxygen content to nitrogen content can be 0.2 or less. In the reaction gas, the ratio of oxygen content to nitrogen content can be 0.1 or less. In the reaction gas, the ratio of oxygen content to nitrogen content can be 0.001 or more. In this case, the surface roughness of the adhesion reinforcement layer 221 can be higher than the surface roughness of the film-forming target surface of the adhesion reinforcement layer 221.

[0279] During the deposition of the adhesion reinforcement layer 221, the atmospheric gas used for forming the thin film that is in contact with the lower surface of the adhesion reinforcement layer 221 can be injected into the chamber within 10 seconds after the atmospheric gas used for forming the thin film that is in contact with the lower surface of the adhesion reinforcement layer 221 has been completely discharged from the sputtering chamber. Alternatively, during the deposition of the adhesion reinforcement layer 221, the atmospheric gas used for forming the thin film that is in contact with the lower surface of the adhesion reinforcement layer 221 can be injected into the chamber within 5 seconds after the atmospheric gas used for forming the thin film that is in contact with the lower surface of the adhesion reinforcement layer 221 has been completely discharged from the sputtering chamber.

[0280] The film formation time of the adhesion reinforcement layer 221 can be from 1 second to 15 seconds. The film formation time of the adhesion reinforcement layer 221 can be from 2 seconds to 8 seconds.

[0281] In this case, the surface roughness value of the attached reinforcement layer 221 can be relatively easily controlled within a preset range.

[0282] The surface roughness Rsk value of the adhesion reinforcement layer 221 formed by the film formation process of the adhesion reinforcement layer 221 can be below -1.

[0283] The values ​​of Rsk, Rku, Rq, Ra, and Rz are values ​​evaluated according to ISO 4287.

[0284] When the attachment reinforcement layer 221 is viewed from a cross section, the contour portion above the baseline (i.e., the average height line in the surface contour) of the attachment reinforcement layer 221 is called a peak, while the contour portion below the baseline is called a valley.

[0285] By controlling the Rsk value of the adhesion enhancement layer 221, the asymmetry of the surface profile of the adhesion enhancement layer 221 can be controlled, thereby enhancing the adhesion between the adhesion enhancement layer 221 and the film located on the upper or lower surface of the adhesion enhancement layer 221.

[0286] The surface roughness Rsk value of the adhesion reinforcement layer 221 formed during the film formation process can be -1 or less. Alternatively, the Rsk value can be -2 or less. Or, the Rsk value can be -3 or more. In this case, the multilayer light-shielding film 20 can exhibit excellent durability during the cleaning process.

[0287] The surface roughness Rku value of the adhesion reinforcement layer 221 formed during the film formation process can be 10 or higher.

[0288] The contact area between the adhesion enhancement layer 221 and the film located adjacent to the adhesion enhancement layer 221 can be increased by adjusting the sharpness of the peaks and valleys of the adhesion enhancement layer 221. This improves the adhesion between the adhesion enhancement layer 221 and the film located on its upper and lower surfaces.

[0289] The surface roughness Rku value of the adhesion enhancement layer 221 formed during the film formation process can be 10 or higher. The Rku value can be 12 or higher. The Rku value can be 15 or lower. In this case, the inter-film adhesion within the multilayer light-shielding film 20 can be improved.

[0290] The surface roughness Rq value of the adhesion reinforcement layer 221 formed during the film formation process can be 0.2 nm or higher. Alternatively, the Rq value can be 0.4 nm or higher. Or, the Rq value can be 5 nm or lower. Or, the Rq value can be 1.5 nm or lower.

[0291] The surface roughness Ra value of the adhesion reinforcement layer 221 formed during the film formation process can be 0.1 nm or higher. Alternatively, the Ra value can be 0.2 nm or higher. Or, the Ra value can be 1.5 nm or lower. Or, the Ra value can be 1 nm or lower.

[0292] The surface roughness Rz value of the adhesion reinforcement layer formed during the film formation process can be 4.5 nm or higher. Alternatively, the Rz value can be 6 nm or higher. Or, the Rz value can be 20 nm or lower. Or, the Rz value can be 15 nm or lower.

[0293] In this case, the adhesion enhancement layer can improve the adhesion between the film and the film located adjacent to the adhesion enhancement layer.

[0294] During the deposition of the upper light-shielding layer, the power applied to the sputtering target can be from 1 kW to 2 kW. Alternatively, the power applied to the sputtering target can be from 1.2 kW to 1.7 kW. In this case, the upper light-shielding layer can have relatively low roughness characteristics and can suppress the generation of particles caused by the unevenness of the multilayer light-shielding film surface.

[0295] During the deposition of the upper light-shielding layer, the sputtering target can be charged at least 15 seconds after the thin film (such as the reinforcement layer) immediately adhering to the lower surface of the upper light-shielding layer is formed. Alternatively, the target can be charged at least 20 seconds after the film is formed. Or, the target can be charged within 30 seconds of the film being formed. In these cases, the upper light-shielding layer can possess preset light-shielding and etching characteristics.

[0296] During the formation of the upper light-shielding layer, the ratio of the flow rate of the reactive gas to the flow rate of the inactive gas in the atmosphere can be 0.3 to 0.7. The aforementioned flow rate ratio can be 0.4 to 0.6.

[0297] During the formation of the upper light-shielding layer, the ratio of oxygen content to nitrogen content in the reaction gas can be less than 0.3. Alternatively, the ratio can be less than 0.1. Or, the ratio can be greater than 0.001.

[0298] In this case, the etching rate of the upper light-shielding layer is relatively lower than that of the first light-shielding film, and the side of the patterned multilayer light-shielding film can be formed to be relatively close to the surface perpendicular to the light-transmitting substrate.

[0299] During the deposition of the upper light-shielding layer, the atmosphere gas for the upper light-shielding layer deposition process can be injected into the chamber within 10 seconds after the atmosphere gas for forming the thin film (e.g., the attachment reinforcement layer) that is in contact with the lower surface of the upper light-shielding layer has been completely discharged from the sputtering chamber. Alternatively, during the deposition of the upper light-shielding layer, the atmosphere gas for the upper light-shielding layer deposition process can be injected into the chamber within 5 seconds after the atmosphere gas for forming the thin film that is in contact with the lower surface of the upper light-shielding layer has been completely discharged from the sputtering chamber. In this case, it is helpful to give the multilayer light-shielding film excellent extinction properties and improve the shape controllability of the patterned multilayer light-shielding film.

[0300] The deposition process of the upper light-shielding layer can be performed for 10 to 30 seconds. Alternatively, it can be performed for 15 to 25 seconds. In this case, it can help to make the sides of the multilayer light-shielding patterned film have a shape that is nearly perpendicular to the light-transmitting substrate.

[0301] The multilayer light-shielding film prepared by the above method includes: a first light-shielding film; and a second light-shielding film located on the first light-shielding film. The second light-shielding film may include an upper light-shielding layer and an adhesion reinforcement layer. The adhesion reinforcement layer may be located between the upper light-shielding layer and the first light-shielding film. The description of the structure, roughness characteristics, composition, film thickness, optical properties, etc. of the multilayer light-shielding film is repeated from the previous description, and therefore will be omitted.

[0302] Semiconductor device manufacturing methods

[0303] A method for manufacturing a semiconductor device according to another embodiment of this specification includes: a preparation step, which involves setting up a light source, a photomask, and a semiconductor wafer coated with a resist film; an exposure step, which involves selectively transmitting light incident from the light source onto the semiconductor wafer through the photomask and emitting the light; and a development step, which involves developing a pattern on the semiconductor wafer.

[0304] The aforementioned photomask includes: a light-transmitting substrate; and a multilayer light-shielding pattern film located on the light-transmitting substrate.

[0305] The aforementioned multilayer light-shielding patterned film includes: a first light-shielding film; and a second light-shielding film disposed on the first light-shielding film and comprising at least one of a transition metal, oxygen, and nitrogen.

[0306] The side surface of the aforementioned multilayer light-shielding pattern film includes a detection zone, which corresponds to the interval between a point spaced apart from a point on the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and a point spaced apart from a point on the lower surface of the second light-shielding film to the upper surface of the second light-shielding film.

[0307] The surface roughness (Wr) of the above detection range satisfies the conditions of the first equation below.

[0308] First Form

[0309] 0nm <Wr-Wo≤3nm

[0310] In the first formula above, Wo is the surface roughness (unit: nm) of the detection range MR before the soaking and cleaning process.

[0311] The above Wr represents the surface roughness (unit: nm) of the above detection range MR after immersion in SC-1 solution for 800 seconds and rinsing with ozone water.

[0312] The above SC-1 solution is a solution containing 14.3% by weight of NH4OH, 14.3% by weight of H2O2 and 71.4% by weight of H2O.

[0313] The ozone water mentioned above is a solution containing 20 ppm (by weight) of ozone, using ultrapure water as a solvent.

[0314] 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 below 200 nm. Alternatively, the exposure light can be ArF light with a wavelength of 193 nm.

[0315] A lens can be further 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. As a lens, there are no limitations as long as it is generally applicable to the ArF semiconductor wafer exposure process. For example, the aforementioned lens could be a lens made of calcium fluoride (CaF2).

[0316] During the exposure step, exposure light can be selectively transmitted onto the semiconductor wafer using a photomask. In this case, a portion of the incident exposure light within the resist film may undergo chemical denaturation.

[0317] In the development step, the semiconductor wafer that has already undergone exposure can be treated with a developing solution to develop a pattern on the semiconductor wafer. When the applied resist solution is a positive resist, the portion of the resist film in which the incident exposure light is emitted may be dissolved by the developing solution. When the applied resist solution is a negative resist, the portion of the resist film in which the exposure light is not emitted may be dissolved by the developing solution. The resist film is formed into a film with a resist pattern by the developing solution treatment. The pattern can be formed on the semiconductor wafer by using the above resist pattern as a mask. The explanation of the photomask is repeated above, so it will be omitted.

[0318] The specific embodiments will be described in more detail below.

[0319] Preparation example: Film formation of multilayer light-shielding film

[0320] Example 1: A transparent quartz substrate with a width of 6 inches, a length of 6 inches, and a thickness of 0.25 inches is placed inside the chamber of a DC sputtering apparatus. A chromium target is placed in the chamber such that the T / S distance is 255 mm and the substrate and target form a 25-degree angle.

[0321] An atmosphere gas mixed with Ar:N2:CO2 in a ratio of 3:2:5 is added into the chamber. A power of 1.85kW is applied to the sputtering target, the substrate is rotated at 10RPM, and a sputtering process is performed for 200 to 250 seconds to form the first light-shielding film.

[0322] After the first light-shielding film is formed, an atmosphere gas mixed with Ar:N2 at a volume ratio of 6.5:3.5 is added to the chamber. A 1.85 kW power is applied to the sputtering target, the substrate rotation speed is 10 RPM, and a sputtering process is performed for 5 seconds to form the adhesion enhancement layer. After 20 seconds of the first light-shielding film formation, power is applied to the sputtering target, and an atmosphere gas is injected within 5 seconds after the atmosphere gas used to form the first light-shielding film has been completely discharged.

[0323] Example 2: Except that an atmosphere gas mixed with Ar:N2 in a volume ratio of 7:3 was added to the chamber when forming the adhesion reinforcement layer, and the power applied to the sputtering target was 1.83kW, the sputtering process was carried out under the same conditions as in Example 1.

[0324] Comparative Example 1: Except that an atmosphere gas mixed in a volume ratio of Ar:N2:O2 = 5:4:1 was added to the chamber when forming the adhesion reinforcement layer, and the power applied to the sputtering target was 1.8kW, the sputtering process was carried out under the same conditions as in Example 1.

[0325] Comparative Example 2: Except that when forming the adhesion reinforcement layer, an atmosphere gas mixed with Ar:N2 in a volume ratio of 5.5:4.5 was added to the chamber, the power applied to the sputtering target was 1kW, and the sputtering process was performed for 8 seconds, the sputtering process was performed under the same conditions as in Example 1.

[0326] Example 3: On the adhesion enhancement layer of a sample prepared under the same conditions as in Example 1, an atmosphere gas mixed with Ar:N2 at a volume ratio of 6.5:3.5 was added to the chamber. A power of 1.5 kW was applied to the sputtering target, and the substrate rotation speed was 10 RPM. A sputtering process was performed for 10 to 30 seconds under the conditions described above to form an upper light-shielding layer. After 20 seconds of forming the adhesion enhancement layer, power was applied to the sputtering target, and an atmosphere gas was injected within 5 seconds after the atmosphere gas used to form the adhesion enhancement layer was completely discharged.

[0327] Example 4: On the adhesion enhancement layer of the sample prepared under the same conditions as the sample in Example 2, an atmosphere gas mixed with Ar:N2 in a volume ratio of 6.5:3.5 was added into the chamber. The power applied to the sputtering target was 1.5kW, the substrate rotation speed was 10RPM, and a sputtering process was performed for 10 to 30 seconds under the conditions described above to form an upper light-shielding layer.

[0328] Comparative Example 3: On the adhesion enhancement layer of the specimen prepared under the same conditions as the specimen in Example 2, an atmosphere gas mixed with Ar:N2 in a volume ratio of 6.5:3.5 was added into the chamber, the power applied to the sputtering target was 1.5kW, the substrate rotation speed was 10RPM, and a sputtering process was performed for 10 to 30 seconds under the conditions described above to form an upper light-shielding layer.

[0329] Comparative Example 4: On the adhesion enhancement layer of the specimen prepared under the same conditions as the specimen in Example 2, an atmosphere gas mixed with Ar:N2 in a volume ratio of 6.5:3.5 was added into the chamber, the power applied to the sputtering target was 1.5kW, the substrate rotation speed was 10RPM, and a sputtering process was performed for 10 to 30 seconds to form an upper light-shielding layer.

[0330] Comparative Example 5: A first light-shielding film was formed on a light-transmitting substrate under the same conditions as the first light-shielding film formation conditions in Example 1.

[0331] Comparative Example 6: A first light-shielding film was formed on a light-transmitting substrate under the same conditions as the first light-shielding film formation conditions in Example 3. Then, an upper light-shielding layer was formed on the first light-shielding layer under the same conditions as the upper light-shielding layer formation conditions in Example 3.

[0332] The film-forming conditions for each embodiment and comparative example are described in Table 1 below.

[0333] Evaluation example: Surface roughness inspection

[0334] The surface roughness values ​​Rq, Ra, and Rz of the adhesion reinforcement layers in Examples 1 and 2 and Comparative Examples 1 and 2 were tested according to ISO 4287.

[0335] In addition, the surface roughness Rsk and Rku values ​​of the adhesion enhancement layer of Example 1, the first light-shielding film of Comparative Example 5, and the upper light-shielding layer of Comparative Example 6 were tested according to ISO 4587.

[0336] Specifically, in a region with a width of 1µm and a length of 1µm at the center of the light-shielding film, the roughness parameter values ​​of each embodiment and comparative example were detected using an XE-150 model from Park Systems Co., Ltd. in non-contact mode at a scanning speed of 0.5Hz. The XE-150 model used the PPP-NCHR, a cantilever model from Park Systems Co., Ltd., as a probe.

[0337] The test results for each embodiment and comparative example are recorded in Table 2 below.

[0338] Evaluation example: Thickness measurement of each membrane and layer

[0339] For the test pieces of the embodiments and comparative examples described above, the thicknesses of the first light-shielding film, the attachment reinforcement layer, and the upper light-shielding layer were measured. Specifically, the test pieces of each embodiment and comparative example were processed to a size of 15 mm in width and 15 mm in length. Then, the upper surface of the processed test piece was subjected to focused ion beam (FIB) treatment, and a TEM image of the cross-section of the test piece was detected using a JEM-2100F HR model manufactured by JEOL Ltd. The thickness of each film and each layer was detected from the measured TEM image.

[0340] The test results for each embodiment and comparative example are recorded in Table 3 below.

[0341] Evaluation example: Surface roughness detection under the second light-shielding film

[0342] After cutting the specimens of Examples 3 and 4 and Comparative Examples 3 and 4, cross-sectional images of the specimens were detected by TEM. Specifically, the specimens were processed to a size of 15 mm in width and 15 mm in length, and the surface of the processed specimens was treated with focused ion beam (FIB). Then, the TEM images of the specimens were detected using a JEM-2100F HR type manufactured by JEOL Ltd. Then, the interface between the second light-shielding film and the first light-shielding film was traced from the detected images, and the Rz value of the lower surface of the second light-shielding film was calculated from the traced line according to the Rz value calculation method standardized by ISO 4287.

[0343] In each embodiment and comparative example, if the calculated Rz value is less than 4 nm, it is evaluated as ○, and if the calculated Rz value is greater than 4 nm, it is evaluated as ×. The results are recorded in Table 2 below.

[0344] Evaluation Example: Optical Property Testing of Multilayer Light-Shielding Film

[0345] For the test pieces of Examples 3 and 4, and Comparative Examples 3 and 4, the transmittance and optical density for exposure light with a wavelength of 193 nm were measured. Specifically, the transmittance and optical density for exposure light with a wavelength of 193 nm for each example and comparative example were measured using an MG-PRO model from Nano-View Co., Ltd. (Korea).

[0346] The test results for each embodiment and comparative example are recorded in Table 3 below.

[0347] Evaluation example: Detection of the composition content of each layer of a multilayer light-shielding film.

[0348] XPS analysis was used to determine the elemental content of each layer and film in each embodiment and comparative example. Specifically, test pieces were prepared by machining photomask blanks of each embodiment and comparative example to a size of 15 mm in width and 15 mm in length. After placing the test pieces in a K-α type detection instrument manufactured by Thermo Scientific, an area with a width of 4 mm and a length of 2 mm located at the center of the test piece was etched to determine the elemental content of each layer and film. The detection results for each embodiment and comparative example are recorded in Table 4 below.

[0349] Evaluation example: Roughness testing of the sides of a multi-layer light-shielding patterned film before and after cleaning.

[0350] For the specimens of Examples 3 and 4, and Comparative Examples 3 and 4, the Wr and Wo values ​​were measured. Specifically, a multilayer light-shielding pattern film was formed by patterning the multilayer light-shielding film of the specimens of Examples 3 and 4, and Comparative Examples 3 and 4. Then, the specimens were processed to a size of 15 mm in width and 15 mm in length, and the surface of the processed specimens was subjected to focused ion beam (FIB) treatment. The TEM image of the processed specimens was then detected using a JEM-2100F HR model manufactured by JEOL Ltd. The profile corresponding to the MR detection region in the side surface of the multilayer light-shielding film 20 was traced from the TEM image, and the Wo value was calculated from the traced line according to the Ry calculation method standardized in ISO 4287.

[0351] Subsequently, the test piece including the aforementioned multilayer light-shielding patterned film was immersed in an SC-1 solution containing 14.3 wt% NH4OH, 14.3 wt% H2O2, and 71.4 wt% H2O for 800 seconds, followed by a rinsing process using ultrapure water as the solvent and containing 20 ppm (by weight) ozone. For the test piece after the rinsing process, the Wr value was calculated using the same method as for calculating the Wo value.

[0352] The test results for each embodiment and comparative example are recorded in Table 3 below.

[0353] Table 1

[0354]

[0355] Table 2

[0356]

[0357] Table 3

[0358]

[0359]

[0360] Table 4

[0361]

[0362] As shown in Table 2 above, compared with Comparative Examples 5 and 6, the Rsk value of the adhesion reinforcement layer surface of Example 1 is relatively low, while the Rku value is relatively high. Furthermore, it was found that Examples 1 and 2 have relatively high Rq, Ra, and Rz values ​​compared with Comparative Examples 1 and 2.

[0363] In Table 3 above, the lower surface roughness of the second light-shielding film of Examples 3 and 4 was evaluated as less than 1 nm, while the lower surface roughness of Comparative Examples 3, 4, and 6 was evaluated as greater than 3 nm.

[0364] In Examples 3 and 4, the transmittance for light with wavelengths below 193 nm measured was less than 1.1%, while in Comparative Examples 3, 4, and 6, the transmittance for light with wavelengths below 193 nm measured was more than 1.4%. In Examples 3 and 4, the optical concentration for light with wavelengths below 193 nm measured was more than 1.9, while in Comparative Examples 3, 4, and 6, the optical concentration for light with wavelengths below 193 nm measured was less than 1.9.

[0365] The Wr-Wo values ​​of Examples 3 and 4 were evaluated as ○, while the Wr-Wo values ​​of Comparative Examples 3 and 4 were evaluated as ×.

[0366] As can be seen from Table 4 above, in the embodiments, the measured Cr content of the adhesion enhancement layer is higher than that of the first light-shielding film, while in Comparative Examples 2 and 4, the measured Cr content of the adhesion enhancement layer is not high compared with that of the first light-shielding film.

[0367] The preferred embodiments have been described in detail above, but the scope of the present invention is not limited thereto. Various modifications and improvements made by those skilled in the art based on the basic concepts of the present invention as defined in the appended claims are also within the scope of the present invention.

Claims

1. A photomask, characterized in that, include: Transparent substrate, and A multi-layer light-shielding patterned film is disposed on the above-mentioned light-transmitting substrate; The aforementioned multilayer light-shielding patterned film includes: The first light-blocking film, and The second light-shielding film is disposed on the first light-shielding film and contains at least one of a transition metal, oxygen, and nitrogen. The aforementioned first light-shielding film contains 35 atomic% to 55 atomic% of a transition metal. The aforementioned second light-shielding film contains 55 atomic% to 75 atomic% of the aforementioned transition metal. The side surface of the aforementioned multilayer light-shielding patterned film includes a detection zone, which corresponds to the interval between points spaced apart from the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and points spaced apart from the lower surface of the second light-shielding film to the upper surface of the second light-shielding film on the side surface of the aforementioned multilayer light-shielding patterned film. The surface roughness of the above-mentioned detection interval satisfies the conditions of the first equation below. First form: 0nm <Wr-Wo≤3nm, In the first formula above, The aforementioned Wo represents the surface roughness of the detection zone prior to the immersion and cleaning processes, expressed in nm. The above Wr represents the surface roughness of the detection area after immersion in standard Clean-1 solution for 800 seconds and rinsing with ozone water, and its unit is nm. The above-mentioned standard cleaning-1 solution is a solution containing 14.3% by weight NH4OH, 14.3% by weight H2O2, and 71.4% by weight H2O. The ozone water mentioned above is a solution that uses ultrapure water as a solvent and contains 20 ppm of ozone by weight.

2. A photomask preform, characterized in that, include: Transparent substrate, and A multi-layer light-shielding film is disposed on the aforementioned light-transmitting substrate; The aforementioned multilayer light-shielding film includes: The first light-blocking film, and The second light-shielding film is disposed on the first light-shielding film and contains at least one of a transition metal, oxygen, and nitrogen. The aforementioned first light-shielding film contains 35 atomic% to 55 atomic% of a transition metal. The aforementioned second light-shielding film contains 55 atomic% to 75 atomic% of the aforementioned transition metal. The side surface of the aforementioned multilayer light-shielding film includes a detection zone, which corresponds to the interval between points spaced apart from the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and points spaced apart from the lower surface of the second light-shielding film to the upper surface of the second light-shielding film on the side surface of the multilayer light-shielding film. The surface roughness of the above-mentioned detection interval satisfies the conditions of the first equation below. First form: 0nm <Wr-Wo≤3nm, In the first formula above, The aforementioned Wo represents the surface roughness of the detection zone prior to the immersion and cleaning processes, expressed in nm. The above Wr represents the surface roughness of the detection area after immersion in standard Clean-1 solution for 800 seconds and rinsing with ozone water, and its unit is nm. The above-mentioned standard cleaning-1 solution is a solution containing 14.3% by weight NH4OH, 14.3% by weight H2O2, and 71.4% by weight H2O. The ozone water mentioned above is a solution that uses ultrapure water as a solvent and contains 20 ppm of ozone by weight.

3. The photomask preform according to claim 2, characterized in that, The first light-shielding film and the second light-shielding film are configured to form an interface. The aforementioned detection interval corresponds to the interval between a point 5 nm apart from the interface to the lower surface of the first light-shielding film and a point 5 nm apart from the interface to the upper surface of the second light-shielding film.

4. The photomask preform according to claim 2, characterized in that, The first light-shielding film and the second light-shielding film are configured to form an interface. The surface roughness of the above-mentioned detection interval is the largest in the interval corresponding to the above-mentioned interface.

5. The photomask preform according to claim 2, characterized in that, The surface roughness of the lower surface of the second light-shielding film is above 4 nm.

6. The photomask preform according to claim 2, characterized in that, The aforementioned second light-shielding film includes: Upper light-shielding layer, and An attachment reinforcement layer is disposed between the upper light-shielding layer and the first light-shielding film; The aforementioned first light-shielding film also contains oxygen and nitrogen. The content of the transition metal in the aforementioned attached reinforcing layer is higher than the content of the transition metal in the aforementioned first light-shielding film, and is higher than or equal to the content of the transition metal in the aforementioned upper light-shielding layer.

7. The photomask preform according to claim 6, characterized in that, The ratio of the content of the transition metal in the aforementioned attached reinforcing layer to the content of the transition metal in the aforementioned first light-shielding film is 1.1 to 2.

5.

8. The photomask preform according to claim 6, characterized in that, The thickness of the above-mentioned adhesion reinforcement layer is to 9. The photomask preform according to claim 2, characterized in that, The aforementioned first light-shielding film also contains oxygen and nitrogen. The sum of the oxygen content and nitrogen content of the first light-shielding film is 40 atomic% to 70 atomic%.

10. The photomask preform according to claim 2, characterized in that, The sum of the oxygen content and nitrogen content of the second light-shielding film is 20 atomic% to 50 atomic%.

11. The photomask preform according to claim 2, characterized in that, The aforementioned transition metals include at least one of Cr, Ta, Ti, and Hf.

12. The photomask preform according to claim 6, characterized in that, After the above-mentioned adhesion enhancement layer has just been formed, the Rsk value of the upper surface of the above-mentioned adhesion enhancement layer is below -1 and the Rku value is above 7.

13. The photomask preform according to claim 6, characterized in that, After the above-mentioned adhesion enhancement layer is formed, the Ra value of the upper surface of the above-mentioned adhesion enhancement layer is 0.5 nm or more.

14. A method for manufacturing a semiconductor device, characterized in that, include: Preparation steps include setting up the light source, photomask, and semiconductor wafer coated with resist. The exposure step involves selectively transmitting light incident from the light source onto the semiconductor wafer through the aforementioned photomask and emitting the light, and... The development step involves developing a pattern on the aforementioned semiconductor wafer; The aforementioned photomask includes: Transparent substrate, and A multilayer light-shielding patterned film is located on the aforementioned light-transmitting substrate; The aforementioned multilayer light-shielding patterned film includes: The first light-blocking film, and The second light-shielding film is disposed on the first light-shielding film and contains at least one of a transition metal, oxygen, and nitrogen. The aforementioned first light-shielding film contains 35 atomic% to 55 atomic% of a transition metal. The aforementioned second light-shielding film contains 55 atomic% to 75 atomic% of the aforementioned transition metal. The side of the aforementioned multi-layered light-shielding patterned film includes a detection area. The aforementioned detection interval corresponds to the interval between points spaced 5 nm apart from the upper surface of the first light-shielding film to the lower surface of the first light-shielding film and points spaced 5 nm apart from the lower surface of the second light-shielding film to the upper surface of the second light-shielding film on the side surface of the multilayer light-shielding pattern film. The surface roughness of the above-mentioned detection interval satisfies the conditions of the first equation below. First form: 0nm <Wr-Wo≤3nm, In the first formula above, The aforementioned Wo represents the surface roughness of the detection zone prior to the immersion and cleaning processes, expressed in nm. The above Wr represents the surface roughness of the detection area after immersion in standard Clean-1 solution for 800 seconds and rinsing with ozone water, and its unit is nm. The above-mentioned standard cleaning-1 solution is a solution containing 14.3% by weight NH4OH, 14.3% by weight H2O2, and 71.4% by weight H2O. The ozone water mentioned above is a solution that uses ultrapure water as a solvent and contains 20 ppm of ozone by weight.

Images