Oxide sputtering target and oxide film

Abstract

The present invention addresses the problem of providing an oxide film which has good processability due to etching, excellent weather resistance (small rate of change in transmittance), and light absorption ability suitable for preventing light reflection. An oxide film which contains molybdenum (Mo), niobium (Nb), zinc (Zn) and oxygen (O), and which has an etching rate of 1 nm / sec or more, a rate of change in average transmittance in the visible light region (wavelength: 400-700 nm) before and after a constant temperature and humidity test of 15% or less, and an average reflectance of 15% or less with respect to incident light in the visible light region (wavelength: 400-700 nm).

Description

Technical Field

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

[0002] Transparent conductive films made of ITO (indium tin oxide) are currently used as wiring members in liquid crystal displays, plasma displays, organic EL displays, touch panels, solar cells, and the like. ITO films offer excellent transmittance for visible light and have the lowest resistivity among oxides, making them an excellent material for wiring members. However, as displays and panels become larger, their resistance increases, making them inadequate for larger displays.

[0003] Due to this issue, research has been underway to replace ITO films with metal films with low resistivity as wiring components. However, when metal films are used as wiring components, they reflect visible light, reducing the visibility of displays and panels. To address this, research is underway to form a film (also called a black matrix) near the metal film that absorbs reflected light, thereby suppressing light reflection caused by the metal film and improving visibility.

[0004] Regarding films that reduce light reflection, the applicant previously proposed a technology involving a thin film of an oxide composed of Nb, Mo, and O (oxygen), which exhibits light absorption capabilities suitable for preventing light reflection (Patent Document 1). This oxide film is a light-absorbing film with good processability due to etching and excellent weather resistance. Furthermore, Patent Document 2 discloses a technology involving a sputtering target for producing a light-absorbing layer using a target material containing an oxide phase and having an oxygen content lower than the stoichiometric composition.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2019 / 176552

[0008] Patent Document 2: Japanese Patent Application No. 2019-529705 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] The technical problem of the present invention is to provide an oxide film having good processability brought about by etching, excellent weather resistance (small change rate of transmittance), and light absorption ability suitable for preventing light reflection, and an oxide sputtering target suitable for forming the oxide film.

[0011] Solutions for solving problems

[0012] The oxide sputtering target disclosed herein has the following key points: it contains molybdenum (Mo), niobium (Nb), zinc (Zn) and oxygen (O), including Zn2Mo3O8 phase and / or Zn3Mo3O8 phase, and the content ratio of the above Zn is 0.13≤Zn / (Mo+Nb+Zn)≤0.50 in terms of atomic ratio.

[0013] The oxide film disclosed herein has the following key points: it contains molybdenum (Mo), niobium (Nb), zinc (Zn) and oxygen (O), has an etching rate of more than 1 nm / s, has an average reflectivity of less than 15% for incident light in the visible light region (wavelength: 400-700 nm), and has a change rate of less than 15% in average transmittance in the visible light region (wavelength: 400-700 nm) before and after a constant temperature and humidity test.

[0014] Effects of the Invention

[0015] According to the present invention, an oxide film having good processability due to etching, excellent weather resistance (small rate of change in transmittance), and light absorption capacity suitable for preventing light reflection can be obtained. In addition, according to the present invention, an oxide sputtering target suitable for forming the above oxide film can be obtained. DETAILED DESCRIPTION

[0016] Research has been underway to use metal films, such as copper and aluminum, with low resistivity, as wiring members for various displays, touch panels, and solar cells. However, when metal films are used as wiring members, they reflect visible light, reducing the visibility of displays and panels. To address this, research is underway to form a film (antireflection film) near the metal film to absorb reflected light, thereby suppressing light reflection caused by the metal film and improving visibility.

[0017] Consider using a metal film as an antireflection film. However, in this case, although the light absorption capacity is excellent, the metal produces metallic reflection that is unique to metals, making it difficult to reduce this metallic reflection. Although forming an oxide film on the metal film as an antireflection film to produce a double-layer structure is also considered, the increase in manufacturing steps reduces production efficiency. On the other hand, considering using a single oxide film as an antireflection film. In this case, although surface reflection can be suppressed by not producing metallic reflection, the light absorption capacity is lower than that of the metal film, resulting in high transmittance. The reflected light from the wiring materials such as the lower electrode is obvious, and sometimes visual confirmation is reduced.

[0018] In this regard, even among single-film oxides, NbO2 and MoO2 are materials with relatively low transmittance and reflectivity for visible light, and are considered useful as anti-reflection films. However, in the case of NbO2 films (alone), although the change over time is small and the weather resistance is excellent, there is a problem that it is difficult to dissolve in etching solutions other than hydrofluoric acid (HF), making it difficult to process by etching. In particular, there is the problem of difficulty in etching simultaneously with a metal film as a wiring material. In addition, in the case of MoO2 films (alone), although the etching rate is fast and can be etched under the same conditions as the metal film, the weather resistance is reduced. In this way, the etching rate and weather resistance are in a trade-off relationship.

[0019] After continuous and in-depth research, the inventors of the present invention have reached the following insights: an oxide film containing molybdenum (Mo), niobium (Nb), zinc (Zn) and oxygen (O), by appropriately adjusting the content ratio of each metal component, thus having good processability brought about by etching (can be etched simultaneously with the metal film) and excellent weather resistance (small change in transmittance), has a light absorption capacity suitable for preventing light reflection, and effectively functions as an anti-reflection film.

[0020] Hereinafter, embodiments of the present invention will be described in detail.

[0021] [About oxide film]

[0022] The oxide film of this embodiment, as a film having good processability due to etching, exhibits an etching rate of 1.0 nm / s or greater when etched under the following conditions. An etching rate of 1.0 nm / s or greater enables etching under the same conditions as metal films (at least copper). Preferably, the etching rate is 1.1 nm / s or greater, more preferably 1.3 nm / s or greater, and even more preferably 1.4 nm / s or greater.

[0023] (Etching Conditions)

[0024] The etching solution uses a hydrogen peroxide (H2O2)-based chemical solution at a temperature of 35°C. An oxide film (sample) formed on a substrate is immersed in the etchant and etched for a predetermined time while stirring. The sample is then removed from the etchant and the film thickness is measured. The etching rate is calculated from the etching time (immersion time) and the reduction in oxide film thickness (= (thickness before etching) - (thickness after etching)).

[0025] With respect to the oxide film of the present embodiment, as a film having excellent weather resistance (small rate of change in transmittance), the rate of change in the average transmittance in the visible light region (wavelength: 400-700 nm) before and after the constant temperature and humidity test is within 15%. The rate of change in the average transmittance is preferably within 14%, more preferably within 13%, and further preferably within 10%. With respect to the average transmittance, the transmittance is measured every 5 nm in the wavelength region (400-700 nm), and the average value is calculated. With respect to the rate of change in transmittance, as a constant temperature and humidity test, a sample of the oxide film formed on the glass substrate is placed in a control room (atmosphere: air, temperature 85°C, humidity 85%), and the transmittance of the sample after 14 days is measured and compared with the measured value of the transmittance before the constant temperature and humidity test to investigate the amount of change. That is, it is calculated by the following formula.

[0026] Transmittance change rate (%) = {(transmittance after constant temperature and humidity test) - (transmittance before constant temperature and humidity test)} / (transmittance before constant temperature and humidity test) × 100

[0027] As for the oxide film of the present embodiment, as a film having a light absorption capacity suitable for preventing light reflection, the average reflectivity of the incident light in the visible light region (wavelength: 400-700nm) is 15% or less. Preferably, the average reflectivity is 14% or less, more preferably 12% or less, and further preferably 10% or less. As for the average reflectivity, the reflectivity is measured every 5nm in the wavelength region (400-700nm), and the average value is calculated. The reflectivity is measured as follows: copper is formed into a film on a glass substrate, a sample of an oxide film stacked on the formed copper is prepared, and the reflectivity of light incident from the film side is measured. It should be noted that reflected light includes specular reflected light and diffuse reflected light, and in this disclosure, it is set as the relative total light reflectivity after the specular reflected light and the diffuse reflected light are combined.

[0028] In the oxide film of the present embodiment, the Zn content ratio (atomic ratio) is calculated as Zn / (Mo+Nb+Zn), and is preferably 0.13 or more. This is because when the Zn content ratio becomes higher, the etching rate of the oxide film increases and the weather resistance is also improved. It is more preferably 0.15 or more, and further preferably 0.20 or more. On the other hand, the Zn content ratio (atomic ratio) is calculated as Zn / (Mo+Nb+Zn), and is preferably 0.50 or less. This is because when the Zn content ratio (atomic ratio) is too high, the light absorption ability of the oxide film is significantly reduced, and when stacked with a metal film, the reflectivity increases.

[0029] In the oxide film of this embodiment, the Mo content ratio (atomic ratio) is calculated as Mo / (Mo+Nb+Zn) and is preferably greater than 0.30. This is because when the Mo content ratio becomes higher, the etching rate of the oxide film increases. It is more preferably greater than 0.33, and further preferably greater than 0.35. On the other hand, the Mo content ratio (atomic ratio) is calculated as Mo / (Mo+Nb+Zn) and is preferably less than 0.70. This is because when the Mo content ratio is too high, the weather resistance of the oxide film deteriorates significantly. It is more preferably less than 0.65.

[0030] In the oxide film of this embodiment, the Nb content ratio (atomic ratio) is preferably 0.15 or more in terms of Nb / (Mo+Nb+Zn). This is because when the Nb content ratio increases, weather resistance improves. It is more preferably 0.18 or more, and further preferably 0.20 or more. On the other hand, the Nb content ratio (atomic ratio) is preferably 0.30 or less in terms of Nb / (Mo+Nb+Zn). This is because when the Nb content ratio is too high, the etching rate of the oxide film is significantly reduced. It is more preferably 0.28 or less, and further preferably 0.26 or less.

[0031] The oxide film thickness of this embodiment is preferably 15 nm to 1000 nm. If the film thickness is less than 15 nm, the light absorption capacity may be reduced. On the other hand, if the film thickness exceeds 1000 nm, film formation takes longer than necessary, which is not preferred. However, the film thickness is ultimately determined by the device design and is not limited to this thickness as long as the light absorption capacity can be guaranteed. It is preferably 30 nm to 500 nm.

[0032] The oxide film of this embodiment is preferably amorphous. This is because it has the following advantages: compared with crystalline films, the film stress is small and homogeneous, and the film has fewer defects. Due to these advantages, the probability of peeling and defects when forming the film on a flexible substrate can be reduced. In this disclosure, whether the oxide film is amorphous is determined by analyzing the oxide film using X-ray diffraction, as will be described later, and judging by the presence or absence of diffraction peaks within a specified range.

[0033] [Oxide sputtering target]

[0034] The oxide sputtering target of this embodiment contains molybdenum (Mo), niobium (Nb), zinc (Zn), and oxygen (O), and includes a Zn2Mo3O8 phase and / or a Zn3Mo3O8 phase, wherein the Zn content ratio (atomic ratio) is 0.13≤Zn / (Mo+Nb+Zn)≤0.50. The oxide sputtering target of this embodiment is useful for forming the oxide film of this embodiment.

[0035] In the oxide sputtering target of the present embodiment, the Zn content ratio (atomic ratio) is calculated as Zn / (Mo+Nb+Zn) for more than 0.13. This is because when the Zn content ratio becomes higher, the etching rate of the oxide film formed using the sputtering target increases, and the weather resistance is also improved. It is more preferably more than 0.15, and further preferably more than 0.20. On the other hand, in the oxide sputtering target of the present embodiment, the Zn content ratio (atomic ratio) is calculated as less than 0.50 using Zn / (Mo+Nb+Zn). This is because when the Zn content ratio (atomic ratio) is too high, the light absorption ability of the oxide film formed using the sputtering target is significantly reduced, and when stacked with a metal film, the reflectivity will increase.

[0036] In the oxide sputtering target of the present embodiment, the Mo content ratio (atomic ratio) is calculated as Mo / (Mo+Nb+Zn), and is preferably 0.30 or more. This is because when the Mo content ratio becomes higher, the etching rate of the oxide film formed using the sputtering target increases. It is more preferably 0.33 or more, and further preferably 0.35 or more. On the other hand, the Mo content ratio (atomic ratio) is calculated as Mo / (Mo+Nb+Zn), and is preferably 0.70 or less. This is because when the Mo content ratio 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.

[0037] In the oxide sputtering target of the present embodiment, the Nb content ratio (atomic ratio) is measured in terms of Nb / (Mo+Nb+Zn), and is preferably 0.15 or more. This is because when the Nb content ratio becomes higher, the weather resistance of the oxide film formed using the sputtering target is improved. It is more preferably 0.18 or more, and further preferably 0.20 or more. On the other hand, the Nb content ratio (atomic ratio) is measured in terms of Nb / (Mo+Nb+Zn), and is preferably 0.30 or less. This is because when the Nb content ratio is too high, the etching rate of the oxide film formed using the sputtering target is significantly reduced. It is more preferably 0.28 or less, and further preferably 0.26 or less.

[0038] The oxide sputtering target of this embodiment contains a Zn2Mo3O8 phase and / or a Zn3Mo3O8 phase. The crystal stability of the Zn2Mo3O8 phase and / or the Zn3Mo3O8 phase is higher than that of a single Mo oxide, and it is expected to improve weather resistance. The presence of the Zn2Mo3O8 phase and the Zn3Mo3O8 phase can be confirmed by X-ray diffraction analysis (XRD).

[0039] In the present disclosure, the presence of the Zn2Mo3O8 phase is determined when the ratio I2 / I0 of the XRD peak intensity I2 at the (102) plane attributed to the Zn2Mo3O8 phase and the background intensity I0 satisfies I2 / I0>2. Furthermore, the presence of the Zn3Mo3O8 phase is determined when the ratio I3 / I0 of the XRD peak intensity I3 at the (006) plane attributed to the Zn3Mo3O8 phase and the background intensity I0 satisfies I3 / I0>2.

[0040] The relative density of the oxide sputtering target of this embodiment is preferably 90% or higher. When the relative density is 90% or higher, the generation of particles during sputtering can be suppressed. More preferably, the relative density is 95% or higher.

[0041] [Method for Manufacturing Oxide Sputtering Target]

[0042] The oxide sputtering target of this embodiment can be produced, for example, as follows.

[0043] Weigh and mix the MoO2 raw material powder, NbO2 raw material powder, and ZnO raw material powder according to 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. A ball mill, for example, is preferably used for simultaneous pulverization and mixing. While Nb2O5 powder and Mo powder can also be considered as raw material powders, achieving high density is difficult due to the significant difference in sintering temperatures between Nb2O5 and Mo.

[0044] Next, the mixed powder obtained by mixing the raw material powders is hot-pressed (uniaxially pressed) in an Ar atmosphere at a sintering temperature of 1100°C to 1200°C, a pressure of 250 MPa or more, and a sintering time of 5 to 10 hours. This produces an oxide sintered body containing Mo, Nb, Zn, and O. The obtained oxide sintered body is then processed into a sputtering target by cutting, grinding, or the like, thereby producing the oxide sputtering target of this embodiment.

[0045] [Method for producing oxide film]

[0046] The oxide thin film of this embodiment can be produced, for example, as follows.

[0047] By placing NbO2, MoO2, ZnO, or Nb-Mo-O sputtering targets separately in a sputtering apparatus and performing co-sputtering, a mixed film of NbO2, MoO2, and ZnO can be formed on a substrate. The film composition can be varied by varying the sputtering power of each target during sputtering.

[0048] Alternatively, the integrated sputtering target produced using the above method can be placed in a sputtering device and sputtered to form a mixed film of NbO2, MoO2, and ZnO on the substrate. In this case, although the composition of the sputtering target and the composition of the film are not exactly the same, it is presumed that they are similar. Since the composition of the sputtering target and the composition of the film are correlated, the sputtering target composition that can produce the desired film composition can be determined by setting conditions. Moreover, by adjusting the oxygen flow rate introduced during sputtering, the oxygen content in the film can be adjusted.

[0049] The film formation conditions of the oxide film can be set as follows, for example.

[0050] <Film formation conditions>

[0051] Sputtering device: ANELVA SPL-500.

[0052] Substrate temperature: room temperature (substrate not heated).

[0053] Film forming atmosphere: Ar or Ar+O2.

[0054] Air pressure: 0.2~2.0Pa.

[0055] Gas flow rate: 50~100sccm.

[0056] Power: 100~1000W (DC, RF).

[0057] Substrate: Corning EagleXG (φ4mm×0.7mm).

[0058] [Example]

[0059] In the present disclosure, various properties of oxide films and oxide sputtering targets were measured under the following conditions.

[0060] <Sputtering target composition>

[0061] The component composition of the sputtering target was measured using the following apparatus.

[0062] Device: SPS3500DD manufactured by SII Corporation.

[0063] Method: ICP-OES (high frequency inductively coupled plasma optical emission spectrometry).

[0064] <Reflectivity and transmittance of oxide films>

[0065] Apparatus: Spectrophotometer UV-2600 manufactured by Shimadzu Corporation.

[0066] Light source: deuterium lamp, halogen lamp.

[0067] Measurement wavelength: 200~1400nm

[0068] Measurement wavelength interval: 5nm.

[0069] Measurement sample:

[0070] (Reflectivity) A sample (Cu laminated film) was used in which a copper film having a thickness of 100 nm was formed on a glass substrate having a thickness of 0.7 mm, and then an oxide film having a thickness of 35 nm was formed.

[0071] (Transmittance) A sample was prepared by forming a 35 nm thick oxide film on a 0.7 mm thick glass substrate.

[0072] <Measurement method>

[0073] (Reflectance) The relative total light reflectance of an integrating sphere (reference sample; mirror) was used.

[0074] (Average Reflectance) The reflectance was measured every 5 nm in the wavelength range (400 to 700 nm), and the average value was calculated.

[0075] (Transmittance) Relative transmittance with respect to reference light.

[0076] (Average Transmittance) The transmittance was measured every 5 nm in the wavelength range (400 to 700 nm), and the average value was calculated.

[0077] In addition, the transmittance and reflectance were both measured using the results obtained when light was incident from the film side.

[0078] Amorphous properties of oxide films

[0079] The presence or absence of diffraction peaks in the X-ray diffraction of the oxide film (sample) is determined. The measurement is performed under the following conditions. If there is no diffraction peak due to the oxide film, it is determined to be an amorphous film. It should be noted that the absence of a diffraction peak means that the maximum peak intensity in 2θ = 10° to 60° is set to I max , the average peak intensity at 2θ = 20° to 25° is defined as I BG When I max / I BG <5. In the table, as the criterion for determining amorphous properties, the condition that I max / I BG The case of <5 is marked as ○, and the case not satisfied is marked as ×.

[0080] Device: Smart Lab manufactured by Rigaku Corporation.

[0081] Tube: Cu-Kα line.

[0082] Tube voltage: 40kV.

[0083] Current: 30mA.

[0084] Determination method: 2θ-θ reflection method.

[0085] Scanning speed: 20° / min.

[0086] Sampling interval: 0.02°.

[0087] Measuring range: 10°~60°.

[0088] Measurement sample: Sample on a glass substrate (EagleXG) (film thickness 100 nm or more).

[0089] Divergence slit: 1°.

[0090] Divergence longitudinal limiting slit: 10mm.

[0091] Scattering slit: 8mm.

[0092] Light receiving slit: open.

[0093] Goniometer: Specimen level type.

[0094] <Film thickness measurement>

[0095] The oxide film thickness was measured using a stylus profilometer (Dektak8 manufactured by Veeco). The oxide film thickness was measured based on the height difference between the film-formed surface and the non-film-formed surface of the glass substrate on which the oxide film was formed.

[0096] <Etching properties of oxide films>

[0097] The etching solution is a hydrogen peroxide (H2O2)-based chemical solution (Pure Etch C200, manufactured by Hayashi Pure Chemical Industries), set at a temperature of 35°C. The oxide film (sample) formed on the substrate is immersed in the etchant and etched for a predetermined time while stirring. The sample is then removed from the etchant and the film thickness is measured. The etching rate is calculated based on the etching time (immersion time) and the change in oxide film thickness (= (thickness before etching) - (thickness after etching)). An etching rate of 1 nm / s or higher indicates good etching processability.

[0098] <Sputtering target composition>

[0099] The composition of the sputtering target was measured using the following method and apparatus.

[0100] Device: SPS3500DD manufactured by SII Corporation.

[0101] Method: ICP-OES (high frequency inductively coupled plasma optical emission spectrometry).

[0102] <Relative density of sputtering target>

[0103] The size (using a vernier caliper) and weight of the sintered body were measured to calculate the dimensional density. Based on the dimensional density and the true density of the sintered body, the relative density (%) was calculated as follows: dimensional density / true density×100.

[0104] The true density is calculated based on the mix ratio of each oxide and their respective theoretical densities.

[0105] When the weight of NbO2 is set to a (wt%), the weight of MoO2 is set to b (wt%), and the weight of ZnO is set to c (wt%), the true density = 100 / (a / 5.90+b / 6.44+c / 5.61).

[0106] Theoretical density of NbO2: 5.90 g / cm 3 .

[0107] Theoretical density of MoO2: 6.44 g / cm 3 .

[0108] Theoretical density of ZnO: 5.61 g / cm 3 .

[0109] <XRD Analysis of Sputtering Target>

[0110] The structure of the sputtering target was analyzed using the following apparatus.

[0111] Device: Smart Lab manufactured by Rigaku Corporation.

[0112] Tube: Cu-Kα line.

[0113] Tube voltage: 40kV.

[0114] Current: 30mA.

[0115] Determination method: 2θ-θ reflection method.

[0116] Scanning speed: 20° / min.

[0117] Sampling interval: 0.02°.

[0118] Measuring range: 10°~60°.

[0119] Sample measurement location: sputtering surface.

[0120] Divergence slit: 1°.

[0121] Divergence longitudinal limiting slit: 10mm.

[0122] Scattering slit: 8mm.

[0123] Light receiving slit: open.

[0124] Goniometer: Specimen horizontal type.

[0125] The XRD peak intensity attributable to the (102) plane of the Zn2Mo3O8 phase in the range of 25.5°≤2θ≤26.5° is defined as I2.

[0126] The XRD peak intensity attributable to the (006) plane of the Zn3Mo3O8 phase in the range of 17.0°≤2θ≤17.5° is defined as I3.

[0127] The average value of the XRD intensity in the range of 21.0°≤2θ≤22.0° was defined as the background value I0.

[0128] (Example 1: Oxide Sputtering Target)

[0129] MoO2 raw material powder, NbO2 raw material powder, and ZnO raw material powder were weighed and mixed to achieve the desired composition. The resulting mixed powder was hot-pressed (uniaxially pressed) in an Ar atmosphere at a sintering temperature of 1100°C, a pressure of 250 MPa or higher, and a sintering time of 10 hours to produce an oxide sintered body. This was then processed to produce an oxide sputtering target. Composition analysis of the oxide sputtering target revealed the following results.

[0130] The Mo content ratio (atomic ratio) represented by Mo / (Mo+Nb+Zn) is 0.517.

[0131] The Nb content ratio (atomic ratio) represented by Nb / (Mo+Nb+Zn) is 0.248.

[0132] The Zn content ratio (atomic ratio) represented by Zn / (Mo+Nb+Zn) was 0.235.

[0133] The relative density of the oxide sputtering target was 96.5%, and regarding the crystal phase, I2 / I0=11.81 and I3 / I0=1.73.

[0134] (Example 2: Oxide Sputtering Target)

[0135] MoO2 raw material powder, NbO2 raw material powder, and ZnO raw material powder were weighed and mixed to achieve the desired composition. The resulting mixed powder was hot-pressed (uniaxially pressed) in an Ar atmosphere at a sintering temperature of 1075°C, a pressure of 250 MPa or higher, and a sintering time of 10 hours to produce an oxide sintered body. This was then processed to produce an oxide sputtering target. Composition analysis of the oxide sputtering target revealed the following results.

[0136] The Mo content ratio (atomic ratio) represented by Mo / (Mo+Nb+Zn) is 0.387.

[0137] The Nb content ratio (atomic ratio) represented by Nb / (Mo+Nb+Zn) is 0.185.

[0138] The Zn content ratio (atomic ratio) represented by Zn / (Mo+Nb+Zn) was 0.428.

[0139] The relative density of the oxide sputtering target was 99.9%, and regarding the crystal phase, I2 / I0=12.72 and I3 / I0=2.32.

[0140] (Comparative Example 1: Oxide Sputtering Target)

[0141] MoO2 raw material powder and NbO2 raw material powder were weighed and mixed to obtain the desired composition. It should be noted that in Comparative Example A-1, ZnO powder was not included. The resulting mixed powder was hot-pressed (uniaxially pressed) in an Ar atmosphere at a sintering temperature of 1150°C, a pressure of 250 MPa or higher, and a sintering time of 10 hours to produce an oxide sintered body. This was then processed to produce an oxide sputtering target. Composition analysis of the oxide sputtering target revealed the following results.

[0142] The Mo content ratio (atomic ratio) represented by Mo / (Mo+Nb+Zn) is 0.90.

[0143] The Nb content ratio (atomic ratio) represented by Nb / (Mo+Nb+Zn) was 0.10.

[0144] In addition, the relative density of the oxide sputtering target was 93.1%.

[0145] (Comparative Example 2: Oxide Sputtering Target)

[0146] MoO2 raw material powder and NbO2 raw material powder were weighed and mixed to obtain the desired composition. It should be noted that in Comparative Example A-2, ZnO powder was not included. The resulting mixed powder was hot-pressed (uniaxially pressed) in an Ar atmosphere at a sintering temperature of 1125°C, a pressure of 250 MPa or higher, and a sintering time of 10 hours to produce an oxide sintered body, which was then processed to produce an oxide sputtering target. Composition analysis of the oxide sputtering target revealed the following results.

[0147] The Mo content ratio (atomic ratio) represented by Mo / (Mo+Nb) was 0.81.

[0148] The Nb content ratio (atomic ratio) represented by Nb / (Mo+Nb) was 0.19.

[0149] In addition, the relative density of the oxide sputtering target was 89.4%.

[0150] (Comparative Example 3: Oxide Sputtering Target)

[0151] MoO2 raw material powder and NbO2 raw material powder were weighed and mixed to obtain the desired composition. It should be noted that in Comparative Example A-3, ZnO powder was not included. The resulting mixed powder was hot-pressed (uniaxially pressed) in an Ar atmosphere at a sintering temperature of 1100°C, a pressure of 250 MPa or higher, and a sintering time of 10 hours to produce an oxide sintered body, which was then processed to produce an oxide sputtering target. Composition analysis of the oxide sputtering target revealed the following results.

[0152] The Mo content ratio (atomic ratio) represented by Mo / (Mo+Nb) was 0.713.

[0153] The Nb content ratio (atomic ratio) represented by Nb / (Mo+Nb) was 0.287.

[0154] In addition, the relative density of the oxide sputtering target was 87.1%.

[0155] (Comparative Example 4: Oxide Sputtering Target)

[0156] NbO2 raw material powder and ZnO raw material powder were weighed and mixed to obtain the desired composition. It should be noted that in Comparative Example A-4, MoO2 powder was not included. The resulting mixed powder was hot-pressed (uniaxially pressed) in an Ar atmosphere at a sintering temperature of 1075°C, a pressure of 250 MPa or higher, 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 are as follows.

[0157] The Mo content ratio (atomic ratio) represented by Nb / (Nb+Zn) is 0.382.

[0158] The Nb content ratio (atomic ratio) represented by Zn / (Nb+Zn) was 0.618.

[0159] In addition, the relative density of the oxide sputtering target was 95.8%.

[0160] The above results are summarized in Table 1.

[0161] [Table 1]

[0162]

[0163] (Example 3: Oxide Film)

[0164] Using the oxide sputtering target prepared in Example 1, sputtering was performed under the aforementioned film formation conditions to form 35 nm thick oxide films on a glass substrate and a copper substrate, respectively. Analysis of various physical properties of the oxide films revealed an etching rate of 1.50 nm / s, a transmittance change of 13.0%, and an average reflectance of 7.60%. Furthermore, the oxide films were confirmed to be amorphous.

[0165] (Example 4: Oxide Film)

[0166] Using the oxide sputtering target prepared in Example 2, sputtering was performed under the aforementioned film formation conditions to form 35 nm thick oxide films on a glass substrate and a copper substrate, respectively. Analysis of various physical properties of the oxide films revealed an etching rate of 1.52 nm / s, a transmittance change of 6.5%, and an average reflectance of 10.60%. Furthermore, the oxide films were confirmed to be amorphous.

[0167] (Example 5: Oxide Film)

[0168] Using the oxide sputtering target and ZnO sputtering target prepared in Comparative Example 3, co-sputtering was performed to form 35 nm thick oxide films on glass and copper substrates, respectively. The composition of the oxide films was adjusted by controlling the film deposition rate of each sputtering target, as shown in Table 2. Analysis of various physical properties of the oxide films revealed an etching rate of 1.15 nm / s, a transmittance change of 14.4%, and an average reflectivity of 6.9%. Furthermore, the oxide films were confirmed to be amorphous.

[0169] (Example 6: Oxide Film)

[0170] Using the oxide sputtering target and ZnO sputtering target prepared in Comparative Example 3, co-sputtering was performed to form 35 nm thick oxide films on glass and copper substrates, respectively. The composition of the oxide films was adjusted by controlling the film deposition rate of each sputtering target, as shown in Table 2. Analysis of various physical properties of the oxide films revealed an etching rate of 1.45 nm / s, a transmittance variation of 13.7%, and an average reflectivity of 7.8%. Furthermore, the oxide films were confirmed to be amorphous.

[0171] (Example 7: Oxide Film)

[0172] Using the oxide sputtering target and ZnO sputtering target prepared in Comparative Example 3, co-sputtering was performed to form 35 nm thick oxide films on glass and copper substrates, respectively. The composition of the oxide films was adjusted by controlling the film deposition rate of each sputtering target, as shown in Table 2. Analysis of various physical properties of the oxide films revealed an etching rate of 1.48 nm / s, a transmittance change of 7.2%, and an average reflectivity of 10.9%. Furthermore, the oxide films were confirmed to be amorphous.

[0173] Here, although Examples 6 and 7 were oxide films formed by co-sputtering, their respective compositions were similar to those of the oxide films formed using the integrated sputtering targets of Examples 3 and 4, resulting in similar results for various oxide properties. These results demonstrate that oxide films formed by co-sputtering can replicate many of the properties of oxide films formed using integrated sputtering targets. In other words, the composition range of the integrated sputtering target can be determined by considering the various properties of the oxide formed by co-sputtering.

[0174] (Example 8: Oxide Film)

[0175] Using the oxide sputtering target and ZnO sputtering target prepared in Comparative Example 3, co-sputtering was performed to form 35 nm thick oxide films on a glass substrate and a copper substrate, respectively. It should be noted that, as shown in Table 2, the composition of the oxide film was adjusted by controlling the film formation rate of each sputtering target. Analysis of various physical properties of the oxide film revealed an etching rate of 3.10 nm / s, a transmittance change of 6.5%, and an average reflectivity of 13.9%. Furthermore, the oxide film was confirmed to be amorphous.

[0176] (Comparative Example 5)

[0177] Using the oxide sputtering target prepared in Comparative Example 1, sputtering was performed under the aforementioned film formation conditions to form 35 nm thick oxide films on a glass substrate and a copper substrate, respectively. Analysis of various physical properties of the oxide films revealed an etching rate of 2.62 nm / s, a transmittance change of 100.0%, and an average reflectance of 11.87%. Furthermore, the oxide films were confirmed to be amorphous.

[0178] (Comparative Example 6)

[0179] Using the oxide sputtering target prepared in Comparative Example 2, sputtering was performed under the aforementioned film formation conditions to form 35 nm thick oxide films on glass and copper substrates, respectively. Analysis of various physical properties of the oxide films revealed an etching rate of 1.89 nm / s, a transmittance change of 75.5%, and an average reflectance of 6.57%. Furthermore, the oxide films were confirmed to be amorphous.

[0180] (Comparative Example 7)

[0181] Using the oxide sputtering target prepared in Comparative Example 3, sputtering was performed under the aforementioned film formation conditions to form 35 nm thick oxide films on glass and copper substrates, respectively. Analysis of various physical properties of the oxide films revealed an etching rate of 0.58 nm / s, a transmittance change of 16.2%, and an average reflectance of 9.42%. Furthermore, the oxide films were confirmed to be amorphous.

[0182] (Comparative Example 8)

[0183] Using the oxide sputtering target and ZnO sputtering target prepared in Comparative Example 3, co-sputtering was performed to form 35 nm thick oxide films on a glass substrate and a copper substrate, respectively. It should be noted that, as shown in Table 2, the composition of the oxide film was adjusted by controlling the film formation rate of each sputtering target. Analysis of various physical properties of the oxide film revealed an etching rate of 8.50 nm / s, a transmittance change rate of 6.7%, and an average reflectivity of 30.1%. Furthermore, the oxide film was confirmed to be amorphous.

[0184] The above results are summarized in Table 2.

[0185] [Table 2]

[0186]

[0187] Industrial applicability

[0188] The oxide film of this embodiment has good processability due to etching, excellent weather resistance, and a light absorption capacity suitable for preventing light reflection. Furthermore, the oxide sputtering target of this embodiment is most suitable for forming the oxide film of the embodiment of the present invention. The oxide film of this embodiment is very useful as a light absorption film for preventing light reflection caused by metal wiring used in liquid crystal displays, plasma displays, organic EL displays, touch panels, solar cells, etc., as well as a photomask material and for decorative purposes.

Claims

1. An oxide sputtering target, wherein: The oxide sputtering target contains molybdenum Mo, niobium Nb, zinc Zn and oxygen O, and includes a Zn2Mo3O8 phase and / or a Zn3Mo3O8 phase. The Zn content ratio, ie, the atomic ratio, is 0.13≤Zn / (Mo+Nb+Zn)≤0.

50.

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

70.

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

30.

4. The oxide sputtering target according to any one of claims 1 to 4, wherein The relative density of the oxide sputtering target is greater than 90%.

5. An oxide film, wherein: The oxide film contains molybdenum Mo, niobium Nb, zinc Zn and oxygen O. The etching rate of the oxide film is above 1 nm / s, the average reflectivity of the incident light in the visible light region, i.e., the wavelength of 400 to 700 nm, is below 15%, and the change rate of the average transmittance in the visible light region, i.e., the wavelength of 400 to 700 nm, before and after the constant temperature and humidity test is within 15%. The oxide film according to claim 5 , wherein The oxide film contains molybdenum Mo, niobium Nb, zinc Zn and oxygen O. The Zn content ratio, ie, the atomic ratio, is 0.13≤Zn / (Mo+Nb+Zn)≤0.

50.

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

70.

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

30.

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

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

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