Oxide sputtering target and oxide film

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

Oxide sputtering targets and oxide films

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

[0002] Transparent conductive films made of ITO (indium tin oxide) are used as wiring materials in liquid crystal displays, plasma displays, organic EL 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 or panels are enlarged, the resistance increases, creating a problem that makes them incompatible with larger areas.

[0003] For these reasons, the use of metal films with low resistivity as wiring members instead of ITO films has been considered. However, when metal films are used as wiring members, 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 a 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 etching processability and excellent weather resistance. Furthermore, Patent Document 2 discloses a 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.

[0005] International Publication No. 2019 / 176552 Special Publication No. 2019-529705

[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.

[0007] The oxide sputtering target of the present disclosure contains molybdenum (Mo), niobium (Nb), zinc (Zn) and oxygen (O), and Zn ２ Mo ３ O ８ phase and / or Zn ３ Mo ３ O ８ The gist of the present invention is that 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.

[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.

[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 the 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 the oxide single films, NbO ２ and MoO ２ is a material with a relatively low transmittance and reflectance for visible light, and is therefore considered useful as an anti-reflection film. ２ When used alone, the film exhibits little change over time and is excellent in weather resistance, but it is difficult to dissolve in etching solutions other than hydrogen fluoride (HF), making it difficult to process by etching. In particular, it is difficult to simultaneously etch the film with the metal film that is the wiring material. ２ In the case of a film (single layer), the etching rate is fast and it can be etched under the same conditions as a metal film, but the weather resistance is reduced. Thus, there is a trade-off between etching rate and weather resistance.

[0013] As a result of extensive research, the present 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 etching processability (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] [Regarding the oxide film] The oxide film according to this embodiment is a film that 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 a metal film (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 contains hydrogen peroxide (H ２ O ２ A )-based chemical solution is used, and the solution temperature is set to 35°C. An oxide film (sample) formed on a substrate is immersed in the etching solution and etched for a predetermined period of time while being stirred. 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 determined 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 the constant temperature and humidity test, measuring the transmittance of the sample after 14 days, and comparing the measured value with the transmittance before the constant temperature and humidity test to examine the amount of change. That is, the rate of change in transmittance is calculated using the following formula: Rate of change in transmittance (%) = {(Transmittance after constant temperature and humidity test) - (Transmittance before constant temperature and humidity test)} / (Transmittance before constant temperature and humidity test) x 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 every 5 nm 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, 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 ratio (atomic ratio) is preferably 0.13 or more, Zn / (Mo+Nb+Zn). This is because a higher Zn content ratio 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 ratio (atomic ratio) is 0.50 or less, Zn / (Mo+Nb+Zn). This is because if the Zn content ratio (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 ratio (atomic ratio) is preferably 0.30 or more, in terms of Mo / (Mo+Nb+Zn). This is because a higher Mo content ratio 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 ratio (atomic ratio) is preferably 0.70 or less, in terms of Mo / (Mo+Nb+Zn). This is because if the Mo content ratio is too high, the weather resistance of the oxide film will be significantly deteriorated. 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 thickness is less than 15 nm, the light absorption capacity may decrease, while if the 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 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, resulting in 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 is determined by analyzing the oxide film using 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). ２ Mo ３ O ８ phase and / or Zn ３ Mo ３ O ８ 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 ratio (atomic ratio) is Zn / (Mo+Nb+Zn) of 0.13 or more. This is because, as the Zn content ratio 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 ratio (atomic ratio) is Zn / (Mo+Nb+Zn) of 0.50 or less. This is because, if the Zn content ratio (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 an 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 an 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 the 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 the 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 is Zn ２ Mo ３ O ８ phase and / or Zn ３ Mo ３ O ８ It contains Zn phase. ２ Mo ３ O ８ phase and / or Zn ３ Mo ３ O ８ The Zn phase has higher crystal stability than the Mo oxide alone, and is expected to improve weather resistance. ２ Mo ３ O ８ Phase, Zn ３ Mo ３ O ８ The presence or absence of the Zn phase can be confirmed using X-ray diffraction analysis (XRD). ２ Mo ３ O ８ XRD peak intensity I attributed to the (102) plane of the phase ２ and background intensity I ０ Relative to I ２ / I ０ Ga I ２ / I ０ If >2 is satisfied, Zn ２ Mo ３ O ８ It is determined that a Zn phase exists. ３ Mo ３ O ８ XRD peak intensity I attributed to the (006) plane of the phase ３ and background intensity I ０ Relative to I ３ / I ０ Ga I ３ / I ０ If >2 is satisfied, Zn ３ Mo ３ O ８ It is determined that a phase exists.

[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 producing oxide sputtering target] The oxide sputtering target according to this embodiment can be produced, for example, as follows. ２ Raw material powder, NbO ２ The raw material powder and ZnO raw material powder are weighed and mixed to obtain the desired composition. It is preferable to use raw material powder with a purity of 99.9% or more and an average particle size (D50) of 0.5 to 10 μm. As a mixing method, it is preferable to use a ball mill or the like to mix the raw material powder while also pulverizing it. ２ O ５ It is also possible to use Nb powder and Mo powder. ２ O ５ Since the sintering temperatures of Mo and Nb are significantly different, 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 makes it possible to obtain 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 for Producing Oxide Film] The oxide thin film according to this embodiment can be produced, for example, as follows. ２ Sputtering target, MoO ２ A sputtering target, a ZnO sputtering target, or a Nb—Mo—O sputtering target is placed in a sputtering apparatus and simultaneously sputtered to form a NbO film on a substrate. ２ and MoO ２ A mixed film of NbO and ZnO can be formed. At this time, the film composition can be changed by changing the sputtering power of each during sputtering. Alternatively, the integrated sputtering target prepared by the above-mentioned method is placed in a sputtering apparatus, and sputtering is performed to form a mixed film of NbO and ZnO on a substrate. ２ and MoO２ A mixed film of ZnO and ZnO can be formed. In this case, the composition of the sputtering target will not be completely identical to the composition of the film, but it is expected to be a composition close to it. Since there is a relationship between the composition of the sputtering target and the composition of the film, by adjusting the conditions, it is possible to determine the composition of the sputtering target that will allow the desired film composition to be obtained. In addition, the amount of oxygen in the film can be adjusted by adjusting the flow rate of oxygen introduced during sputtering.

[0031] The oxide film may be formed under the following conditions, for example: <Film Formation Conditions> Sputtering device: ANELVA SPL-500 Substrate temperature: room temperature (no substrate heating) Film formation atmosphere: Ar or Ar+O ２ Gas pressure: 0.2 to 2.0 Pa Gas flow rate: 50 to 100 sccm Power: 100 to 1000 W (DC, RF) Substrate: Corning Eagle XG (φ4 mm x 0.7 mm)

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

[0033] <Reflectance and Transmittance of Oxide Film> Apparatus: Shimadzu UV-2600 Spectrophotometer Light Source: Deuterium Lamp, Halogen Lamp Measurement Wavelength: 200-1400 nm Measurement Wavelength Interval: 5 nm Measurement Sample: (Reflectance) A sample (Cu laminated film) was used in which a 100 nm thick copper film was formed on a 0.7 mm thick glass substrate, followed by a 35 nm thick oxide film. (Transmittance) A sample was used in which a 35 nm thick oxide film was formed on a 0.7 mm thick glass substrate. <Measurement Method> (Reflectance) Relative total light reflectance using an integrating sphere (reference sample; specular mirror). (Average Reflectance) Reflectance was measured every 5 nm in the wavelength range (400-700 nm), and the average value was calculated. (Transmittance) Relative transmittance to reference light. (Average Transmittance) Transmittance was measured every 5 nm in the wavelength range (400-700 nm), and the average value was calculated. The transmittance and reflectance were measured when light was incident from the film side.

[0034] <Amorphousness of oxide film> The oxide film (sample) was judged to have a diffraction peak by X-ray diffraction. Measurement was carried out under the following conditions, and if there was no diffraction peak due to the oxide film, it was judged to be an amorphous film. The absence of a diffraction peak means that the maximum peak intensity at 2θ = 10° to 60° is I ｍａｘ , the average peak intensity at 2θ = 20° to 25° is I ＢＧ When I ｍａｘ / I ＢＧ In the table, the criteria for amorphousness are I ｍａｘ / I ＢＧ Cases where <5 was satisfied were marked with a circle, and cases where it was not satisfied were marked with an ×. Apparatus: Rigaku Corporation Smart Lab Tube: Cu-Kα ray Tube voltage: 40 kV Current: 30 mA Measurement method: 2θ-θ reflection method Scan speed: 20° / min Sampling interval: 0.02° Measurement range: 10° to 60° Measurement sample: Sample on glass substrate (Eagle XG) (film thickness 100 nm or more) Divergence slit: 1° Divergence vertical limiting slit: 10 mm Scattering slit: 8 mm Receiving slit: open state Goniometer: sample 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 film-formed surface and the unformed surface of the glass substrate on which the oxide film was formed.

[0036] <Processability of oxide film by etching> The etching solution is hydrogen peroxide (H ２ O ２ An oxide film (sample) formed on a substrate was immersed in the etching solution at a liquid temperature of 35°C using a SiO 2 -based chemical (Pure Etch C200, manufactured by Hayashi Pure Chemical Industries, Ltd.), and etched for a predetermined time while stirring. The sample was then removed from the etching solution, and the film thickness was measured. The etching rate was calculated from the time required for etching (immersion time) and the change in the oxide film thickness (= (film thickness before etching) - (film thickness after etching)). An etching rate of 1 nm / second or higher was determined to be good etching processability.

[0037] <Composition of Sputtering Target> The composition of the sputtering target was measured using the following method and apparatus. Apparatus: SPS3500DD manufactured by SII Corporation 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 x 100. The true density was calculated from the compounding ratio of each oxide and their respective theoretical densities. NbO ２ Weight is a (wt%), MoO ２ When the weight is b (wt%) and the weight of ZnO is c (wt%), the true density = 100 / (a / 5.90 + b / 6.44 + c / 5.61) ２ Theoretical density: 5.90 g / cm ３ MoO ２ Theoretical density: 6.44 g / cm ３ Theoretical density of ZnO: 5.61 g / cm ３

[0039] <XRD analysis of sputtering target> The structure of the sputtering target was analyzed using the following device. Device: Smart Lab manufactured by Rigaku Corporation Tube: Cu-Kα ray Tube voltage: 40 kV Current: 30 mA Measurement method: 2θ-θ reflection method Scan speed: 20° / min Sampling interval: 0.02° Measurement range: 10° to 60° Sample measurement location: sputter surface Divergence slit: 1° Divergence vertical limiting slit: 10 mm Scattering slit: 8 mm Receiving slit: open state Goniometer: sample horizontal type Zn ２ Mo ３ O ８ The XRD peak intensity in the range of 25.5°≦2θ≦26.5°, which is attributed to the (102) plane of the phase, is expressed as I ２ It was defined as: Zn ３ Mo ３ O ８ The XRD peak intensity in the range of 17.0°≦2θ≦17.5°, which is attributed to the (006) plane of the phase, is ３ The average value of the XRD intensity in the range of 21.0°≦2θ≦22.0° was defined as the background I ０ It was defined as follows.

[0040] (Example 1: Oxide sputtering target) MoO ２ Raw material powder, NbO ２ The raw material powder and ZnO raw material powder were weighed and mixed to obtain the desired composition. 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 analysis of the oxide sputtering target revealed the following results: Mo content (atomic ratio) represented by Mo / (Mo+Nb+Zn) was 0.517, Nb content (atomic ratio) represented by Nb / (Mo+Nb+Zn) was 0.248, and Zn content (atomic ratio) represented by Zn / (Mo+Nb+Zn) was 0.235. The relative density of the oxide sputtering target was 96.5%, and the crystalline phase was I. ２ / I ０ = 11.81, I３ / I ０ = 1.73.

[0041] (Example 2: Oxide sputtering target) MoO ２ Raw material powder, NbO ２ The raw material powder and ZnO raw material powder were weighed and mixed to obtain the desired composition. 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 analysis of the oxide sputtering target revealed the following results: Mo content (atomic ratio) represented by Mo / (Mo+Nb+Zn) was 0.387, Nb content (atomic ratio) represented by Nb / (Mo+Nb+Zn) was 0.185, and Zn content (atomic ratio) represented by Zn / (Mo+Nb+Zn) was 0.428. The relative density of the oxide sputtering target was 99.9%, and the crystalline phase was I. ２ / I ０ = 12.72, I ３ / I ０ = 2.32.

[0042] (Comparative Example 1: Oxide Sputtering Target) MoO ２ Raw material powder, NbO ２ The raw material powders 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 analysis of the oxide sputtering target revealed the following results: The Mo content ratio (atomic ratio) represented by Mo / (Mo + Nb + Zn) was 0.90 The Nb content ratio (atomic ratio) represented by Nb / (Mo + Nb + Zn) was 0.10 The relative density of the oxide sputtering target was 93.1%.

[0043] (Comparative Example 2: Oxide Sputtering Target) MoO２ Raw material powder, NbO ２ The raw material powders 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 analysis of the oxide sputtering target revealed the following results: The Mo content ratio (atomic ratio) represented by Mo / (Mo+Nb) was 0.81 The Nb content ratio (atomic ratio) represented by Nb / (Mo+Nb) was 0.19 The relative density of the oxide sputtering target was 89.4%.

[0044] (Comparative Example 3: Oxide Sputtering Target) MoO ２ Raw material powder, NbO ２ The raw material powders 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 analysis of the oxide sputtering target revealed the following results: The Mo content ratio (atomic ratio) represented by Mo / (Mo+Nb) was 0.713 The Nb content ratio (atomic ratio) represented by Nb / (Mo+Nb) was 0.287 The relative density of the oxide sputtering target was 87.1%.

[0045] (Comparative Example 4: Oxide Sputtering Target) NbO ２ The raw material powder and ZnO raw material powder were weighed and mixed to obtain the desired composition. ２No Mo powder was contained. 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) represented by Nb / (Nb + Zn) was 0.382 The Nb content ratio (atomic ratio) represented by Zn / (Nb + Zn) was 0.618 The relative density of the oxide sputtering target was 95.8%. The above results are summarized in Table 1.

[0046]

[0047] (Example 3: Oxide film) Using the oxide sputtering target prepared in Example 1, sputtering was performed under the above-mentioned 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 that the etching rate was 1.50 nm / sec, the rate of change in transmittance was 13.0%, and the average reflectance was 7.60%. It was also confirmed that the oxide film was amorphous.

[0048] (Example 4: Oxide film) Using the oxide sputtering target prepared in Example 2, sputtering was performed under the above-mentioned 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 rate of change in transmittance 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 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 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 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 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 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 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 show 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 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%. It was also confirmed that the oxide film was amorphous.

[0054] (Comparative Example 5) Using the oxide sputtering target prepared in Comparative Example 1, sputtering was performed under the above-mentioned 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 that the etching rate was 2.62 nm / sec, the rate of change in transmittance was 100.0%, and the average reflectance was 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-mentioned 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 1.89 nm / sec, a rate of change in transmittance of 75.5%, and an average reflectance of 6.57%. It was also confirmed that the oxide film was amorphous.

[0056] (Comparative Example 7) Using the oxide sputtering target prepared in Comparative Example 3, sputtering was performed under the above-mentioned 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 that the etching rate was 0.58 nm / sec, the rate of change in transmittance was 16.2%, and the average reflectance was 9.42%. It was also confirmed that the oxide film was amorphous.

[0057] (Comparative Example 8) Using the oxide sputtering target and 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]

[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. Containing molybdenum (Mo), niobium (Nb), zinc (Zn) and oxygen (O), with Zn ２ Mo ３ O ８ phase and / or Zn ３ Mo ３ O ８ phase, and having a content ratio (atomic ratio) of Zn of 0.13 ≦ Zn / (Mo + Nb + Zn) ≦ 0.50, an oxide sputtering target.

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

70.

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

30.

4. The oxide sputtering target according to any one of claims 1 to 3, having 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 / second or more, an average reflectance with respect to incident light in the visible light region (wavelength: 400 to 700 nm) of 15% or less, and a change rate of the average transmittance in the visible light region (wavelength: 400 to 700 nm) within 15% before and after a constant temperature and humidity test.

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

50.

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

70.

8. The oxide film according to claim 5, wherein the content ratio (atomic ratio) of Nb is 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 or more and 1000 nm or less.

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