Oxide sputtering targets and oxide films

Abstract

The present invention addresses the problem of providing an oxide film having good processability by etching and excellent weatherability (small change in transmittance) and having light-absorbing ability suitable for preventing light reflection. The oxide film comprises molybdenum (Mo), niobium (Nb), zinc (Zn), and oxygen (O), has an etching rate of 1 nm / sec or higher, has a change of average transmittance in the visible light region (wavelengths: 400-700 nm) of 15% or less through a constant-temperature, constant-humidity test, and has an average reflectance of incident light in the visible light region (wavelengths: 400-700 nm) of 15% or less.

Description

[Technical Field]

[0001] The present invention relates to an oxide sputtering target and an oxide film. [Background technology]

[0002] Transparent conductive films made of ITO (indium tin oxide) are used as wiring materials in liquid crystal displays, plasma displays, organic electroluminescent displays, touch panels, solar cells, etc. ITO films have excellent transparency to visible light and low resistivity among oxides, making them an excellent material for wiring materials. However, when displays and panels are enlarged, the resistance increases, creating the problem of being unable to accommodate larger areas.

[0003] For these reasons, the use of metal films with low resistivity as wiring materials instead of ITO films has been considered. However, when metal films are used as wiring materials, the metal films reflect visible light, which causes a problem of reducing the visibility of displays and panels. To address this problem, it has been considered to form a film (also called a black matrix) that can absorb reflected light near the metal film to suppress light reflection by the metal film and improve visibility.

[0004] Regarding films that reduce light reflection, the applicant previously proposed technology relating to an oxide thin film of Nb, Mo, and O (oxygen) that has light absorption properties suitable for preventing light reflection (Patent Document 1). This oxide thin film is a light-absorbing film that has good processability through etching and excellent weather resistance. Furthermore, Patent Document 2 discloses technology relating to a sputtering target for producing a light-absorbing layer from a target material that contains an oxide phase and has an oxygen content lower than the stoichiometric composition. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 176552 [Patent Document 2] Special Publication No. 2019-529705 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an oxide film that has good processability by etching, excellent weather resistance (small rate of change in transmittance), and light absorption ability suitable for preventing light reflection, and an oxide sputtering target suitable for forming the oxide film. [Means for solving the problem]

[0007] The oxide sputtering target of the present disclosure contains molybdenum (Mo), niobium (Nb), zinc (Zn), and oxygen (O), and includes a Zn2Mo3O8 phase and / or a Zn3Mo3O8 phase, and the Zn content satisfies the atomic ratio of 0.13≦Zn / (Mo+Nb+Zn)≦0.50.

[0008] The oxide film of the present disclosure contains molybdenum (Mo), niobium (Nb), zinc (Zn) and oxygen (O), has an etching rate of 1 nm / sec or more, has an average reflectance of 15% or less for incident light in the visible light range (wavelength: 400 to 700 nm), and exhibits a change rate of 15% or less in average transmittance in the visible light range (wavelength: 400 to 700 nm) before and after a constant temperature and humidity test. [Effects of the Invention]

[0009] According to the present invention, it is possible to obtain an oxide film that has good processability by etching, excellent weather resistance (small rate of change in transmittance), and light absorption ability suitable for preventing light reflection. Furthermore, according to the present invention, it is possible to obtain an oxide sputtering target suitable for forming the oxide film. DETAILED DESCRIPTION OF THE INVENTION

[0010] The use of metal films such as copper and aluminum, which have low resistivity, as wiring materials for various displays, touch panels, solar cells, and the like has been considered. However, when metal films are used as wiring materials, the metal films reflect visible light, causing a problem of reducing the visibility of displays and panels. To address this issue, it has been considered to form a film (anti-reflection film) that can absorb reflected light near the metal film to suppress light reflection by the metal film and improve visibility.

[0011] It is conceivable to use a metal film as an anti-reflection coating. However, although this has excellent light absorption properties, it generates metallic reflections specific to metals, making it difficult to reduce this metallic reflection. It is also conceivable to form an oxide film on the metal film as an anti-reflection coating to create a two-layer structure, but this would increase the number of manufacturing steps and reduce production efficiency. On the other hand, it is conceivable to use a single oxide film as an anti-reflection coating. In this case, no metallic reflection occurs, so surface reflection is suppressed, but since the light absorption properties are inferior to those of a metal film, the transmittance is high, and reflected light from wiring materials such as the lower electrode becomes noticeable, which can deteriorate visibility.

[0012] In this regard, among single-film oxides, NbO2 and MoO2 are materials with relatively low visible light transmittance and low reflectance, and are therefore considered useful as anti-reflection films. However, while NbO2 films (alone) exhibit little change over time and have excellent weather resistance, they are difficult to dissolve in etching solutions other than hydrogen fluoride (HF), making them difficult to process by etching. In particular, simultaneous etching with metal films, which are used as wiring materials, is difficult. Furthermore, MoO2 films (alone) have a fast etching rate and can be etched under the same conditions as metal films, but their weather resistance is reduced. Thus, there is a trade-off between etching rate and weather resistance.

[0013] As a result of extensive research, the inventors have discovered that an oxide film containing molybdenum (Mo), niobium (Nb), zinc (Zn) and oxygen (O), in which the content ratio of each metal component is appropriately adjusted, has good processability by etching (simultaneous etching with a metal film is possible), excellent weather resistance (small rate of change in transmittance), and light absorption ability suitable for preventing light reflection, and thus functions effectively as an anti-reflection film. Hereinafter, embodiments of the present invention will be described in detail.

[0014] [About oxide films] The oxide film according to this embodiment has good processability by etching, and has an etching rate of 1.0 nm / sec or more when etched under the following conditions. If the etching rate is 1.0 nm / sec or more, etching is possible under the same conditions as for metal films (at least copper). The etching rate is preferably 1.1 nm / sec or more, more preferably 1.3 nm / sec or more, and even more preferably 1.4 nm / sec or more.

[0015] (Etching conditions) The etching solution is a hydrogen peroxide (H2O2) based chemical solution, and the solution temperature is set to 35°C. The oxide film (sample) formed on the substrate is immersed in the etching solution and etched for a specified period of time while stirring. The sample is then removed from the etching solution and the film thickness is measured. The etching rate is calculated from the time required for etching (immersion time) and the amount of reduction in the oxide film thickness (= (film thickness before etching) - (film thickness after etching)).

[0016] The oxide film according to this embodiment has excellent weather resistance (small rate of change in transmittance), and the rate of change in average transmittance in the visible light region (wavelength: 400 to 700 nm) before and after a constant temperature and humidity test is within 15%. Preferably, the rate of change in average transmittance is within 14%, more preferably within 13%, and even more preferably within 10%. The average transmittance is calculated by measuring the transmittance every 5 nm in the wavelength region (400 to 700 nm) and calculating the average value. The rate of change in transmittance was measured by leaving a sample of an oxide film formed on a glass substrate in a controlled room (atmosphere: air, temperature 85°C, humidity 85%) as a constant temperature and humidity test, measuring the transmittance of the sample after 14 days, and comparing the measured transmittance with the measured value before the constant temperature and humidity test to determine the amount of change. That is, it is calculated using the following formula: Change in transmittance (%) = {(Transmittance after constant temperature and humidity test) - (Transmittance before constant temperature and humidity test)} / (Transmittance before constant temperature and humidity test) × 100

[0017] The oxide film according to this embodiment is a film having light absorption properties suitable for preventing light reflection, and has an average reflectance of 15% or less for incident light in the visible light range (wavelength: 400 to 700 nm). Preferably, the average reflectance is 14% or less, more preferably 12% or less, and even more preferably 10% or less. The average reflectance is calculated by measuring the reflectance at 5 nm intervals in the wavelength range (400 to 700 nm) and calculating the average value. The reflectance is measured by forming a copper film on a glass substrate, laminating an oxide film on the copper film to prepare a sample, and measuring the reflectance of light incident from the film side. Note that reflected light can be classified into specular reflected light and diffuse reflected light. In the present disclosure, the relative total light reflectance is defined as the sum of specular reflected light and diffuse reflected light.

[0018] In the oxide film of this embodiment, the Zn content (atomic ratio) is preferably 0.13 or more, Zn / (Mo+Nb+Zn). This is because a higher Zn content increases the etching rate of the oxide film and improves weather resistance. It is more preferably 0.15 or more, and even more preferably 0.20 or more. On the other hand, it is preferable that the Zn content (atomic ratio) is 0.50 or less, Zn / (Mo+Nb+Zn). This is because if the Zn content (atomic ratio) is too high, the light absorption ability of the oxide film will be significantly reduced, and the reflectance will increase when laminated with a metal film.

[0019] In the oxide film of this embodiment, the Mo content (atomic ratio) is preferably 0.30 or more, in terms of Mo / (Mo+Nb+Zn). This is because a higher Mo content increases the etching rate of the oxide film. It is more preferably 0.33 or more, and even more preferably 0.35 or more. On the other hand, the Mo content (atomic ratio) is preferably 0.70 or less, in terms of Mo / (Mo+Nb+Zn). This is because if the Mo content is too high, the weather resistance of the oxide film deteriorates significantly. It is more preferably 0.65 or less.

[0020] In the oxide film of this embodiment, the Nb content ratio (atomic ratio) is preferably 0.15 or more, expressed as Nb / (Mo+Nb+Zn). This is because a higher Nb content ratio improves weather resistance. It is more preferably 0.18 or more, and even more preferably 0.20 or more. On the other hand, it is preferably 0.30 or less, expressed as Nb / (Mo+Nb+Zn). This is because if the Nb content ratio is too high, the etching rate of the oxide film will decrease significantly. It is more preferably 0.28 or less, and even more preferably 0.26 or less.

[0021] The oxide film of this embodiment preferably has a thickness of 15 nm or more and 1000 nm or less. If the film thickness is less than 15 nm, the light absorption capacity may decrease, while if the film thickness exceeds 1000 nm, it takes more time than necessary to form the film, which is not preferable. However, since the film thickness is ultimately determined by the device design, it is not limited to this thickness as long as at least the light absorption capacity is ensured. The film thickness is preferably 30 nm or more and 500 nm or less.

[0022] The oxide film of this embodiment is preferably amorphous (non-crystalline). Compared to a crystallized film, the oxide film has a smaller film stress and is more homogeneous, which has the advantage of fewer film defects. This advantage reduces the probability of peeling or defects occurring when the film is formed on a flexible substrate. In the present disclosure, whether an oxide film is amorphous or not is determined by analyzing the oxide film by X-ray diffraction and determining whether a diffraction peak is present in a predetermined range, as described below.

[0023] [Oxide sputtering target] The oxide sputtering target according to this embodiment contains molybdenum (Mo), niobium (Nb), zinc (Zn), and oxygen (O), and includes a Zn2Mo3O8 phase and / or a Zn3Mo3O8 phase, and the Zn content (atomic ratio) satisfies 0.13≦Zn / (Mo+Nb+Zn)≦0.50. The oxide sputtering target according to this embodiment is useful for forming the oxide film according to this embodiment.

[0024] In the oxide sputtering target of this embodiment, the Zn content (atomic ratio) is Zn / (Mo+Nb+Zn) of 0.13 or more. This is because, as the Zn content increases, the etching rate of the oxide film formed using this sputtering target increases and the weather resistance also improves. It is preferably 0.15 or more, and more preferably 0.20 or more. On the other hand, in the oxide sputtering target of this embodiment, the Zn content (atomic ratio) is Zn / (Mo+Nb+Zn) of 0.50 or less. This is because, if the Zn content (atomic ratio) is too high, the light absorption ability of the oxide film formed using this sputtering target significantly decreases, and the reflectance increases when laminated with a metal film.

[0025] In the oxide sputtering target of this embodiment, the Mo content (atomic ratio) is preferably 0.30 or more, in terms of Mo / (Mo+Nb+Zn). This is because a higher Mo content increases the etching rate of the oxide film formed using the sputtering target. It is more preferably 0.33 or more, and even more preferably 0.35 or more. On the other hand, the Mo content (atomic ratio) is preferably 0.70 or less, in terms of Mo / (Mo+Nb+Zn). This is because if the Mo content is too high, the weather resistance of the oxide film formed using the sputtering target is significantly deteriorated. It is more preferably 0.65 or less.

[0026] In the oxide sputtering target of this embodiment, the Nb content ratio (atomic ratio) is preferably 0.15 or more, expressed as Nb / (Mo+Nb+Zn). This is because a higher Nb content ratio improves the weather resistance of an oxide film formed using the sputtering target. It is more preferably 0.18 or more, and even more preferably 0.20 or more. On the other hand, it is preferably 0.30 or less, expressed as Nb / (Mo+Nb+Zn). This is because if the Nb content ratio is too high, the etching rate of an oxide film formed using the sputtering target will be significantly reduced. It is more preferably 0.28 or less, and even more preferably 0.26 or less.

[0027] The oxide sputtering target according to this embodiment contains a Zn2Mo3O8 phase and / or a Zn3Mo3O8 phase. The Zn2Mo3O8 phase and / or the Zn3Mo3O8 phase have higher crystal stability than Mo oxide alone, and are expected to improve weather resistance. The presence or absence of the Zn2Mo3O8 phase and the Zn3Mo3O8 phase can be confirmed using X-ray diffraction analysis (XRD). In the present disclosure, the Zn2Mo3O8 phase is determined to be present when the ratio I2 / I0 of the XRD peak intensity I2 attributable to the (102) plane of the Zn2Mo3O8 phase to the background intensity I0 satisfies I2 / I0 > 2. Also, the Zn3Mo3O8 phase is determined to be present when the ratio I3 / I0 of the XRD peak intensity I3 attributable to the (006) plane of the Zn3Mo3O8 phase to the background intensity I0 satisfies I3 / I0 > 2.

[0028] The oxide sputtering target according to this embodiment preferably has a relative density of 90% or more. When the relative density is 90% or more, the generation of particles during sputtering can be suppressed. More preferably, the relative density is 95% or more.

[0029] [Method for manufacturing oxide sputtering targets] The oxide sputtering target according to this embodiment can be produced, for example, as follows. MoO2 raw material powder, NbO2 raw material powder, and ZnO raw material powder are weighed and mixed to obtain the desired composition. The raw material powders preferably have a purity of 99.9% or higher and an average particle size (D50) of 0.5 to 10 μm. The mixing method preferably uses a ball mill or the like to mix the powders while also pulverizing them. It is also possible to use Nb2O5 powder and Mo powder as the raw material powders, but since Nb2O5 and Mo have significantly different sintering temperatures, it is difficult to achieve high density. Next, the mixed powder obtained by mixing the raw material powders is subjected to hot press sintering (uniaxial pressure sintering) in an Ar atmosphere at a sintering temperature of 1100°C or higher and 1200°C or lower, a pressure of 250 MPa or higher, and a sintering time of 5 to 10 hours. This allows for the production of an oxide sintered body containing Mo, Nb, Zn, and O. Next, the obtained oxide sintered body is cut, polished, etc., and processed into a sputtering target, thereby producing the oxide sputtering target according to this embodiment.

[0030] [Method of manufacturing oxide film] The oxide thin film according to this embodiment can be produced, for example, as follows. By placing an NbO2 sputtering target, MoO2 sputtering target, ZnO sputtering target, or Nb-Mo-O sputtering target in a sputtering device and simultaneously sputtering, a mixed film of NbO2, MoO2, and ZnO can be formed on a substrate. At this time, the film composition can be changed by changing the sputtering power of each target during sputtering. Alternatively, the integrated sputtering target prepared by the above-described method can be placed in a sputtering apparatus and sputtered to form a mixed film of NbO2, MoO2, and ZnO on a substrate. The composition of the sputtering target will not be exactly the same as the composition of the film, but it is expected to be close to it. Since there is a relationship between the composition of the sputtering target and the composition of the film, it is possible to determine the composition of the sputtering target that will produce the desired film composition by adjusting the conditions. Furthermore, the amount of oxygen in the film can be adjusted by adjusting the oxygen flow rate introduced during sputtering.

[0031] The conditions for forming the oxide film can be, for example, as follows. <Film formation conditions> Sputtering equipment: ANELVA SPL-500 Substrate temperature: Room temperature (no substrate heating) Film deposition atmosphere: Ar or Ar+O2 Gas pressure: 0.2 to 2.0 Pa Gas flow rate: 50 to 100 sccm Power: 100~1000W (DC, RF) Substrate: Corning EagleXG (φ4mm x 0.7mm) [Example]

[0032] In the present disclosure, the properties of the oxide film and the oxide sputtering target were measured under the following conditions. <Composition of sputtering targets> The component composition of the sputtering target was measured using the following device. Equipment: SII SPS3500DD Method: ICP-OES (inductively coupled plasma optical emission spectroscopy)

[0033] <Reflectance and transmittance of oxide film> Equipment: SHIMADZU spectrophotometer UV-2600 Light source: deuterium lamp, halogen lamp Measurement wavelength: 200~1400nm Measurement wavelength interval: 5nm Measurement sample: (Reflectivity) A sample (Cu laminated film) was used, which was prepared by depositing a copper film with a thickness of 100 nm on a glass substrate with a thickness of 0.7 mm, followed by depositing an oxide film with a thickness of 35 nm. (Transmittance) A sample was used in which an oxide film with a thickness of 35 nm was formed on a glass substrate with a thickness of 0.7 mm. <Measurement method> (Reflectance) Relative total light reflectance using an integrating sphere (reference sample; specular mirror). (Average reflectance) The reflectance was measured every 5 nm in the wavelength region (400 to 700 nm), and the average value was calculated. (Transmittance) Relative transmittance to the reference light. (Average transmittance) The transmittance was measured every 5 nm in the wavelength region (400 to 700 nm), and the average value was calculated. The transmittance and reflectance were measured when light was incident from the film side.

[0034] <Amorphous nature of oxide film> The oxide film (sample) was judged to be amorphous based on the presence or absence of diffraction peaks by X-ray diffraction. Measurement was carried out under the following conditions, and if no diffraction peaks due to the oxide film were present, the film was judged to be amorphous. The absence of diffraction peaks means that the maximum peak intensity at 2θ = 10° to 60° is max , where I is the average peak intensity at 2θ = 20° to 25°. BG When I max / I BG In the table, the criteria for amorphousness are I max / I BG If the condition <5 was met, it was marked as ○, and if it was not met, it was marked as ×. Equipment: Rigaku Smart Lab Tube: Cu-Kα ray Tube voltage: 40kV Current: 30mA Measurement method: 2θ-θ reflection method Scan speed: 20° / min Sampling interval: 0.02° Measurement range: 10°~60° Measurement sample: Sample on glass substrate (EagleXG) (film thickness 100 nm or more) Divergence slit: 1° Divergence vertical limit slit: 10 mm Scattering slit: 8 mm Receiving slit: open Goniometer: horizontal type

[0035] <Film thickness measurement> The thickness of the oxide film was measured using a stylus-type step gauge (Dektak8 manufactured by Veeco). The thickness of the oxide film was measured from the step between the coated surface and the uncoated surface of the glass substrate on which the oxide film was formed.

[0036] <Processability by etching oxide film> The etching solution used was a hydrogen peroxide (H2O2)-based chemical (Hayashi Pure Chemical Industries, Pure Etch C200), and the solution temperature was set to 35°C. The oxide film (sample) formed on the substrate was immersed in the etching solution and etched for a specified period of time while stirring. The sample was then removed from the etching solution, the film thickness was measured, and the etching rate was calculated from the time required for etching (immersion time) and the change in oxide film thickness (= (film thickness before etching) - (film thickness after etching)). An etching rate of 1 nm / second or higher was considered to indicate good etching processability.

[0037] <Composition of sputtering targets> The composition of the sputtering target was measured using the following method and apparatus. Equipment: SII SPS3500DD Method: ICP-OES (inductively coupled plasma optical emission spectroscopy)

[0038] <Relative density of sputtering target> The dimensions (using a vernier caliper) and weight of the sintered body were measured to calculate the dimensional density, and the relative density (%) was calculated from the dimensional density and the true density of the sintered body as follows: dimensional density / true density×100. The true density was calculated from the compounding ratio of each oxide and the theoretical density of each oxide. When the weight of NbO2 is a (wt%), the weight of MoO2 is b (wt%), and the weight of ZnO is c (wt%), the true density = 100 / (a / 5.90 + b / 6.44 + c / 5.61) Theoretical density of NbO2: 5.90 g / cm 3 Theoretical density of MoO2: 6.44 g / cm 3 Theoretical density of ZnO: 5.61 g / cm 3

[0039] <XRD analysis of sputtering targets> The structure of the sputtering target was analyzed using the following equipment. Equipment: Rigaku Smart Lab Tube: Cu-Kα ray Tube voltage: 40kV Current: 30mA Measurement method: 2θ-θ reflection method Scan speed: 20° / min Sampling interval: 0.02° Measurement range: 10°~60° Sample measurement location: sputtered surface Divergence slit: 1° Divergence vertical limit slit: 10 mm Scattering slit: 8 mm Receiving slit: open Goniometer: horizontal type The XRD peak intensity in the range of 25.5°≦2θ≦26.5°, which is attributed to the (102) plane of the Zn2Mo3O8 phase, was defined as I2. The XRD peak intensity in the range of 17.0°≦2θ≦17.5°, which is attributed to the (006) plane of the Zn3Mo3O8 phase, was defined as I3. The average value of the XRD intensity in the range of 21.0°≦2θ≦22.0° was defined as the background I0.

[0040] (Example 1: Oxide sputtering target) MoO2 raw material powder, NbO2 raw material powder, and ZnO raw material powder were weighed and mixed to obtain the desired composition. The resulting mixed powder was subjected to hot press sintering (uniaxial pressure sintering) in an Ar atmosphere at a sintering temperature of 1100°C, a pressure of 250 MPa or more, and a sintering time of 10 hours to produce an oxide sintered body, which was then processed to produce an oxide sputtering target. The composition of the oxide sputtering target was analyzed, and the results were as follows: The Mo content (atomic ratio) expressed as Mo / (Mo+Nb+Zn) is 0.517 The Nb content ratio (atomic ratio) expressed as Nb / (Mo+Nb+Zn) is 0.248 The Zn content (atomic ratio) expressed as Zn / (Mo+Nb+Zn) is 0.235 The relative density of the oxide sputtering target was 96.5%, and the crystal phase was I2 / I0=11.81 and I3 / I0=1.73.

[0041] (Example 2: Oxide sputtering target) MoO2 raw material powder, NbO2 raw material powder, and ZnO raw material powder were weighed and mixed to obtain the desired composition. The resulting mixed powder was subjected to hot press sintering (uniaxial pressure sintering) in an Ar atmosphere at a sintering temperature of 1075°C, a pressure of 250 MPa or more, and a sintering time of 10 hours to produce an oxide sintered body, which was then processed to produce an oxide sputtering target. The composition of the oxide sputtering target was analyzed, and the results were as follows: The Mo content (atomic ratio) expressed as Mo / (Mo+Nb+Zn) is 0.387 The Nb content ratio (atomic ratio) expressed as Nb / (Mo+Nb+Zn) is 0.185 The Zn content (atomic ratio) expressed as Zn / (Mo+Nb+Zn) is 0.428 The relative density of the oxide sputtering target was 99.9%, and the crystal phase was I2 / I0=12.72 and I3 / I0=2.32.

[0042] (Comparative Example 1: Oxide Sputtering Target) MoO2 raw material powder and NbO2 raw material powder were weighed and mixed to obtain the desired composition. In Comparative Example A-1, ZnO powder was not added. The obtained mixed powder was subjected to hot press sintering (uniaxial pressure sintering) in an Ar atmosphere at a sintering temperature of 1150°C, a pressure of 250 MPa or more, and a sintering time of 10 hours to produce an oxide sintered body, which was then processed to produce an oxide sputtering target. The composition of the oxide sputtering target was analyzed, and the results were as follows. The Mo content (atomic ratio) expressed as Mo / (Mo+Nb+Zn) is 0.90 The Nb content ratio (atomic ratio) expressed as Nb / (Mo+Nb+Zn) is 0.10 The relative density of the oxide sputtering target was 93.1%.

[0043] (Comparative Example 2: Oxide Sputtering Target) MoO2 raw material powder and NbO2 raw material powder were weighed and mixed to obtain the desired composition. In Comparative Example A-2, ZnO powder was not added. The obtained mixed powder was subjected to hot press sintering (uniaxial pressure sintering) in an Ar atmosphere at a sintering temperature of 1125°C, a pressure of 250 MPa or more, and a sintering time of 10 hours to produce an oxide sintered body, which was then processed to produce an oxide sputtering target. The composition of the oxide sputtering target was analyzed, and the results were as follows. The Mo content (atomic ratio) expressed as Mo / (Mo+Nb) is 0.81 The Nb content (atomic ratio) expressed as Nb / (Mo+Nb) is 0.19 The relative density of the oxide sputtering target was 89.4%.

[0044] (Comparative Example 3: Oxide Sputtering Target) MoO2 raw material powder and NbO2 raw material powder were weighed and mixed to obtain the desired composition. In Comparative Example A-3, ZnO powder was not added. The obtained mixed powder was subjected to hot press sintering (uniaxial pressure sintering) in an Ar atmosphere at a sintering temperature of 1100°C, a pressure of 250 MPa or more, and a sintering time of 10 hours to produce an oxide sintered body, which was then processed to produce an oxide sputtering target. The composition of the oxide sputtering target was analyzed, and the results were as follows. The Mo content (atomic ratio) expressed as Mo / (Mo+Nb) is 0.713 The Nb content ratio (atomic ratio) expressed as Nb / (Mo+Nb) is 0.287 The relative density of the oxide sputtering target was 87.1%.

[0045] (Comparative Example 4: Oxide Sputtering Target) NbO2 raw material powder and ZnO raw material powder were weighed and mixed to obtain the desired composition. In Comparative Example A-4, MoO2 powder was not added. The obtained mixed powder was subjected to hot press sintering (uniaxial pressure sintering) in an Ar atmosphere at a sintering temperature of 1075°C, a pressure of 250 MPa or more, and a sintering time of 10 hours to produce an oxide sintered body, which was then processed to produce an oxide sputtering target. The composition of the oxide sputtering target was analyzed, and the results were as follows. The Mo content ratio (atomic ratio) expressed as Nb / (Nb+Zn) is 0.382 The Nb content ratio (atomic ratio) expressed as Zn / (Nb+Zn) is 0.618 The relative density of the oxide sputtering target was 95.8%. The above results are summarized in Table 1.

[0046] [Table 1]

[0047] (Example 3: Oxide film) Using the oxide sputtering target prepared in Example 1, sputtering was performed under the above film formation conditions to form oxide films with a thickness of 35 nm on a glass substrate and a copper substrate. Analysis of the physical properties of the oxide films revealed an etching rate of 1.50 nm / sec, a transmittance change rate of 13.0%, and an average reflectance of 7.60%. It was also confirmed that the oxide films were amorphous.

[0048] (Example 4: Oxide film) Using the oxide sputtering target prepared in Example 2, sputtering was performed under the above film formation conditions to form oxide films with a thickness of 35 nm on a glass substrate and a copper substrate. Analysis of the physical properties of the oxide film revealed an etching rate of 1.52 nm / sec, a transmittance change rate of 6.5%, and an average reflectance of 10.60%. It was also confirmed that the oxide film was amorphous.

[0049] (Example 5: Oxide film) Using the oxide sputtering target and the ZnO sputtering target prepared in Comparative Example 3, simultaneous sputtering was performed to deposit oxide films with a thickness of 35 nm on a glass substrate and a copper substrate, respectively. The composition of the oxide film was adjusted by controlling the deposition rate of each sputtering target as shown in Table 2. Analysis of the physical properties of the oxide film revealed an etching rate of 1.15 nm / sec, a rate of change in transmittance of 14.4%, and an average reflectance of 6.9%. It was also confirmed that the oxide film was amorphous.

[0050] (Example 6: Oxide film) Using the oxide sputtering target and the ZnO sputtering target prepared in Comparative Example 3, simultaneous sputtering was performed to deposit oxide films with a thickness of 35 nm on a glass substrate and a copper substrate, respectively. The composition of the oxide film was adjusted by controlling the deposition rate of each sputtering target as shown in Table 2. Analysis of the physical properties of the oxide film revealed an etching rate of 1.45 nm / sec, a rate of change in transmittance of 13.7%, and an average reflectance of 7.8%. It was also confirmed that the oxide film was amorphous.

[0051] (Example 7: Oxide film) Using the oxide sputtering target and the ZnO sputtering target prepared in Comparative Example 3, simultaneous sputtering was performed to deposit oxide films with a thickness of 35 nm on a glass substrate and a copper substrate, respectively. The composition of the oxide film was adjusted by controlling the deposition rate of each sputtering target as shown in Table 2. Analysis of the physical properties of the oxide film revealed an etching rate of 1.48 nm / sec, a rate of change in transmittance of 7.2%, and an average reflectance of 10.9%. It was also confirmed that the oxide film was amorphous.

[0052] Here, Examples 6 and 7 are oxide films formed by co-sputtering, but they were intended to have the same composition as the oxide films formed using the integrated sputtering targets of Examples 3 and 4, respectively, and the physical properties of the oxides were similar. These results demonstrate that the physical properties of oxide films formed using an integrated sputtering target can be reproduced by an oxide film formed by co-sputtering. In other words, it is possible to specify the composition range of an integrated sputtering target by taking into account the physical properties of an oxide film formed by co-sputtering.

[0053] (Example 8: Oxide film) Using the oxide sputtering target and the ZnO sputtering target prepared in Comparative Example 3, simultaneous sputtering was performed to form oxide films with a thickness of 35 nm on a glass substrate and a copper substrate, respectively. The composition of the oxide film was adjusted by controlling the film formation rate of each sputtering target as shown in Table 2. Analysis of the physical properties of the oxide film revealed an etching rate of 3.10 nm / sec, a rate of change in transmittance of 6.5%, and an average reflectance of 13.9%. The oxide film was also confirmed to be amorphous.

[0054] (Comparative Example 5) Using the oxide sputtering target prepared in Comparative Example 1, sputtering was performed under the above film formation conditions to form oxide films with a thickness of 35 nm on a glass substrate and a copper substrate. Analysis of the physical properties of the oxide film revealed an etching rate of 2.62 nm / sec, a rate of change in transmittance of 100.0%, and an average reflectance of 11.87%. It was also confirmed that the oxide film was amorphous.

[0055] (Comparative Example 6) Using the oxide sputtering target prepared in Comparative Example 2, sputtering was performed under the above film formation conditions to form oxide films with a thickness of 35 nm on a glass substrate and a copper substrate. Analysis of the physical properties of the oxide films revealed an etching rate of 1.89 nm / sec, a transmittance change rate of 75.5%, and an average reflectance of 6.57%. It was also confirmed that the oxide films were amorphous.

[0056] (Comparative Example 7) Using the oxide sputtering target prepared in Comparative Example 3, sputtering was performed under the above film formation conditions to form oxide films with a thickness of 35 nm on a glass substrate and a copper substrate. Analysis of the physical properties of the oxide film revealed an etching rate of 0.58 nm / sec, a rate of change in transmittance of 16.2%, and an average reflectance of 9.42%. It was also confirmed that the oxide film was amorphous.

[0057] (Comparative Example 8) Using the oxide sputtering target and the ZnO sputtering target prepared in Comparative Example 3, simultaneous sputtering was performed to form oxide films with a thickness of 35 nm on a glass substrate and a copper substrate, respectively. The composition of the oxide film was adjusted by controlling the film formation rate of each sputtering target as shown in Table 2. Analysis of the physical properties of the oxide film revealed an etching rate of 8.50 nm / sec, a rate of change in transmittance of 6.7%, and an average reflectance of 30.1%. It was also confirmed that the oxide film was amorphous. The above results are summarized in Table 2.

[0058] [Table 2] [Industrial Applicability]

[0059] The oxide film according to this embodiment has good etching processability, excellent weather resistance, and light absorption properties suitable for preventing light reflection. Furthermore, the oxide sputtering target according to this embodiment is ideal for forming the oxide film according to the embodiment of the present invention. The oxide film according to this embodiment is very useful as a light absorption film that prevents light reflection from metal wiring used in liquid crystal displays, plasma displays, organic EL displays, touch panels, solar cells, etc., as a photomask material, and for decorative purposes.

Claims

1. Contains molybdenum (Mo), niobium (Nb), zinc (Zn) and oxygen (O), ２ Mo ３ O ８ phase and / or Zn ３ Mo ３ O ８ phase, and the Zn content ratio (atomic ratio) is 0.13≦Zn / (Mo+Nb+Zn)≦0.

50.

2. 2. The oxide sputtering target according to claim 1, wherein the content ratio (atomic ratio) of Mo satisfies 0.30≦Mo / (Mo+Nb+Zn)≦0.

70.

3. 2. The oxide sputtering target according to claim 1, wherein the Nb content (atomic ratio) satisfies 0.15≦Nb / (Mo+Nb+Zn)≦0.

30.

4. 4. The oxide sputtering target according to claim 1, which has a relative density of 90% or more.

5. An oxide film containing molybdenum (Mo), niobium (Nb), zinc (Zn) and oxygen (O), having an etching rate of 1 nm / sec or more, an average reflectance of 15% or less for incident light in the visible light range (wavelength: 400 to 700 nm), and a change rate of the average transmittance in the visible light range (wavelength: 400 to 700 nm) before and after a constant temperature and humidity test being within 15%. The etching rate is calculated by performing etching under the following conditions. Etching solution: Hydrogen peroxide (H 2 O 2 ) based chemical solution Liquid temperature: 35°C The constant temperature and humidity test is carried out under the following conditions. A sample of the oxide film formed on the glass substrate is left in a controlled room (atmosphere: air, temperature 85° C., humidity 85%) for 14 days.

6. 6. The oxide film according to claim 5, wherein the Zn content (atomic ratio) satisfies 0.13≦Zn / (Mo+Nb+Zn)≦0.

50.

7. 6. The oxide film according to claim 5, wherein the content ratio (atomic ratio) of Mo satisfies 0.30≦Mo / (Mo+Nb+Zn)≦0.

70.

8. 6. The oxide film according to claim 5, wherein the Nb content (atomic ratio) satisfies 0.15≦Nb / (Mo+Nb+Zn)≦0.

30.

9. The oxide film according to any one of claims 5 to 8, having a film thickness of 15 nm to 1000 nm.

10. The oxide film according to any one of claims 5 to 8, which is amorphous.

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