Tungsten oxide-based sintered body, thin film using sintered body, thin film transistor comprising thin film, and display device

Abstract

The present invention provides a tungsten oxide sintered body having excellent low resistance and low reflection properties, a thin film using the sintered body, a thin film transistor comprising the thin film, and a display device.

Description

Tungsten oxide-based sintered body, a thin film using the sintered body, a thin film transistor including the thin film, and a display device

[0001] The present invention relates to a tungsten oxide-based sintered body having excellent low reflection and low resistance characteristics, a sputtering target using said sintered body and a thin film formed therefrom, a thin film transistor including said thin film and a display device.

[0002]

[0003] In general, low-reflectivity conductive thin films are used in flat panel displays ("FPD"), touch screen panels, solar cells, light emitting diodes ("LED"), and organic light emitting diodes ("OLED").

[0004] Indium oxide-tin oxide (In2O3-SnO2) ("ITO") is a representative material for this purpose, and ITO compositions are used to form conductive thin films with high visible light transmittance and electrical conductivity. Although these ITO compositions possess excellent low-reflectivity performance, they are not economically viable; therefore, research is continuing on materials that can replace all or part of indium oxide.

[0005] However, while the focus of these studies is on the low reflectance of thin films formed using target materials, it is necessary to consider chemical and heat resistance properties to enhance the reliability of the thin film for long-term use.

[0006]

[0007] Meanwhile, the inventors have a technical objective of providing a sintered body for a sputtering target that has excellent low-reflection characteristics and low-resistance characteristics simultaneously, by configuring an oxide sintered body with tungsten (W), which is used as a conventional electrode material or wiring material, as the main component, and by including at least two types of specific metal oxides (e.g., M1, M2) and controlling the composition thereof, a metal oxide thin film formed therefrom, and a thin film transistor and a display device having said metal oxide thin film formed thereon.

[0008] Other objects and advantages of the present invention may be more clearly explained by the following detailed description of the invention and claims.

[0009]

[0010] To achieve the above-mentioned technical problem, the present invention provides a tungsten oxide sintered body comprising: tungsten (M); a first metal oxide containing one or more first elements (M1) selected from the group consisting of Nb, Ta, Zr, Ti, and Sn; and a second (quasi)metal oxide containing one or more second elements (M2) selected from the group consisting of Y, Hf, Ge, V, W, Al, Si, Mn, and Co; and, based on 100 weight% of the sintered body, at least 50 weight% of tungsten (M).

[0011] For example, in one embodiment of the present invention, the tungsten (M) may be included in an amount of 50 to 70 weight% based on 100 weight% of the sintered body.

[0012] For example, in one embodiment of the present invention, the first metal oxide may include one or more selected from the group consisting of Nb2O5, Ta2O5, ZrO2, TiO2, and SnO2.

[0013] For example, in one embodiment of the present invention, the first metal oxide may be included in an amount of 20 to 40 weight% based on 100 weight parts of the sintered body.

[0014] For example, in one embodiment of the present invention, the second (quasi)metal oxide may include one or more selected from the group consisting of Y2O3, HfO2, GeO2, WO3, V2O5, Al2O3, SiO2, MnO2, and Co3O4.

[0015] For example, in one embodiment of the present invention, the second metal oxide may be included in an amount of 5 to 15 weight percent based on 100 weight parts of the sintered body.

[0016] For example, in one embodiment of the present invention, the oxide sintered body may have (i) a weight percentage ratio of (M+M1) / (M1) of 2.0 to 4.5% and (ii) a weight percentage ratio of (M+M1+M2) / (M+M1) of 0.9 to 1.5%.

[0017] For example, in one embodiment of the present invention, the sintered body is WM1 X O Y (11 < X < 27, 32 < Y < 78) may include a crystalline phase and a tungsten metal crystalline phase.

[0018] For example, in one embodiment of the present invention, the average grain particle size (D) constituting the sintered body is 50 ) is 1 to 30 μm, and the resistivity is 3×10 -3 It is less than Ωcm, and the relative density can be 95% or more.

[0019] In addition, the present invention provides a sputtering target comprising the aforementioned tungsten oxide sintered body.

[0020] In addition, the present invention provides an oxide thin film formed from the aforementioned sputtering target.

[0021] For example, in one embodiment of the present invention, the thickness of the oxide thin film may be 5 to 50 nm.

[0022] For example, in one embodiment of the present invention, the oxide thin film may satisfy at least two of the following physical properties.

[0023] The average reflectance at wavelengths of 360 to 740 nm is 25% or less, and

[0024] Sheet resistance is 3.0 × 10 at a thickness of 100 to 500 Å 3 It is Ω / sq or less, and

[0025] The average particle size of the crystalline phase contained in the thin film is 5 to 30 nm.

[0026] In addition, the present invention comprises a transparent substrate; the aforementioned tungsten oxide thin film formed on the transparent substrate; and a copper thin film formed on the tungsten oxide thin film; wherein the average reflectance at a wavelength of 360 to 740 nm measured at the transparent substrate side is 25% or less, and the sheet resistance at a thickness of 100 to 500 Å is 3.0 × 10⁻⁶ 3 A thin film laminate with a thickness of Ω / sq or less is provided.

[0027] In addition, the present invention provides a thin film transistor comprising the aforementioned thin film, wherein the thin film is included as any one of a gate layer, a source layer, and a drain layer.

[0028] Furthermore, the present invention provides a display device comprising the aforementioned tungsten oxide-based thin film.

[0029]

[0030] According to one embodiment of the present invention, by optimizing the composition by using tungsten metal as the main component and including at least two types of specific metal oxides (e.g., M1, M2), the sinterability of the tungsten oxide-based sintered body can be improved and high density secured, thereby simultaneously securing low reflection characteristics and low resistance characteristics.

[0031] Accordingly, the tungsten oxide-based sintered body and sputtering target according to the present invention can be usefully applied to form electrodes or wiring used in the TFT structure of LCDs and OLEDs, and can achieve high operational reliability of a thin-film transistor or display device comprising an oxide thin film formed from the oxide sintered body.

[0032] The effects according to the present invention are not limited to those exemplified above, and a wider variety of effects are included in this specification.

[0033]

[0034] Figure 1 is a graph evaluating the reflectance of tungsten-based oxide thin films according to Examples 1-2 and Comparative Examples.

[0035]

[0036] The present invention will be described in detail below.

[0037] All terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0038] Furthermore, throughout the specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Also, throughout the specification, the terms "above" or "on" mean not only cases where a part is located above or below the subject part but also cases where another part is located in between, and do not necessarily mean that it is located above based on the direction of gravity. Furthermore, in this specification, terms such as "first," "second," etc., are used to distinguish components from one another, rather than indicating an arbitrary order or degree of importance.

[0039]

[0040] Sintered Body and Sputtering Target

[0041] One example of the present invention is a metal oxide sintered body for producing a sputtering target having tungsten as the main component.

[0042] Conventional oxide targets with molybdenum (Mo) as the main component mainly exhibited only low-reflection characteristics and showed poor performance in terms of low-resistance characteristics and heat resistance.

[0043] In contrast, the present invention changes molybdenum (Mo) to tungsten (W) and simultaneously adopts at least two types of specific metal oxides (e.g., M1, M2), such as a first metal oxide (M1) with excellent chemical resistance and a second metal oxide (M2) capable of improving low reflection and low resistance characteristics, and by organically controlling the content of these to form an optimized composition, low reflection and low resistance characteristics can be secured simultaneously.

[0044] For one specific example, the sintered body comprises tungsten (M); a first metal oxide containing one or more first elements (M1) selected from the group consisting of Nb, Ta, Zr, Ti, and Sn; and a second (quasi)metal oxide containing one or more second elements (M2) selected from the group consisting of Y, Hf, Ge, V, W, Al, Si, Mn, and Co; and has a composition comprising at least 50 weight% of tungsten (M) metal based on 100 weight% of the sintered body.

[0045] For example, the sintered body may have a composition satisfying the following formulas (i) to (iii), where the ratio (weight%) of the content of tungsten (M), a first element (M1), and a second element (M2) to the total metal element excluding oxygen is denoted as [M], [M1], and [M2], respectively.

[0046] (i) 50 ≤ [M] ≤ 70

[0047] (ii) 20 ≤ [M1] ≤ 40

[0048] (iii) 5 ≤ [M2] ≤ 15

[0049] Here, the total of 100 weight% of the metal components means that the sum of each metal component, e.g., M+M1+M2, included in the sintered body is 100, and the weight ratio may mean that the sum of M+M1+M2 of a specific atom is 1. If necessary, the weight% and weight ratios described above may each include unavoidable impurities, in which case the aforementioned figures may be partially changed.

[0050] In the above formula (i), the content of tungsten (M) is 50 to 70 weight%, specifically 55 to 65 weight%. Also, in the above formula (ii), the content of the first metal element (M1) is 20 to 40 weight%, specifically 25 to 35 weight%. Also, in the above formula (iii), the content of the second (quasi)metal element (M2) is 5 to 15 weight%, specifically 7 to 13 weight%.

[0051] For other specific examples, the tungsten (M), first element (M1), and second element (M2) contained in the sintered body may satisfy the following weight ratios.

[0052] (iv) 0.70 ≤ (M+M1) / (M+M1+M2) < 1.00

[0053] (v) 0.55 ≤ (M+M2) / (M+M1+M2) ≤ 0.80

[0054] (vi) 0.25 ≤ (M1+M2) / (M+M1+M2) ≤ 0.50

[0055] In the above formula (iv), the weight ratio of tungsten (M) to the first element (M1) is 0.87 to 0.98, and specifically, it may be 0.87 to 0.95. Also, in the above formula (v), the weight ratio of tungsten (M) to the second element (M2) is 0.55 to 0.77, and specifically, it may be 0.55 to 0.73. Also, in the above formula (vi), the weight ratio of the first element (M1) to the second element (M2) is 0.25 to 0.48, and specifically, it may be 0.25 to 0.47.

[0056] As another specific example, the weight ratio of tungsten (M), the first element (M1), and the second element (M2) present in the oxide sintered body may be 0.5 to 0.7 : 0.2 to 0.4 : 0.05 to 0.15, and specifically 0.55 to 0.65 : 0.25 to 0.35 : 0.07 to 0.13.

[0057] The tungsten metal (M) included in the oxide sintered body according to the present invention is the main component constituting the tungsten oxide sintered body.

[0058] In conventional tungsten oxide sintered bodies, only tungsten metal or tungsten oxide was used. When only tungsten metal is used, it is difficult to obtain the desired low-reflection effect due to the metal, and when only tungsten oxide is used, low-resistance characteristics could not be obtained due to the low conductivity of the oxide. Accordingly, in the present invention, the low-resistance and low-reflection characteristics can be secured by including tungsten metal (M) as a main component and simultaneously using at least one second metal oxide (M2), such as tungsten oxide, which can impart the low-reflection and low-resistance characteristics described below.

[0059] The above tungsten metal (M) may be included in at least 50 weight% based on 100 weight% of the sintered body, specifically in the range of 55 to 80 weight%, more specifically in the range of 60 to 70 weight%.

[0060] One of the additive components included in the oxide sintered body according to the present invention is a first metal oxide containing one or more first elements (M1) selected from the group consisting of Nb, Ta, Zr, Ti, and Sn.

[0061] This first metal oxide (M1) is an oxide dopant that improves chemical resistance and heat resistance properties, and the chemical resistance and heat resistance properties of the tungsten oxide sintered body can be enhanced by adding the first metal oxide. The first metal oxide is not particularly limited as long as it is a component having a form in which oxygen is bonded to at least one element (M1) among Nb, Ta, Zr, Ti, and Sn, and may include, for example, one or more selected from the group consisting of Nb2O5, Ta2O5, ZrO2, TiO2, and SnO2. Preferably, it may be Nb2O5, Ta2O5, or a mixture thereof. In the following description, the first metal oxide component is symbolized and indicated as M1.

[0062] The first metal oxide may be included in an amount of 20 to 40 weight% based on 100 weight% of the sintered body, and specifically, 20 to 38 weight%.

[0063] Another additive component included in the oxide sintered body according to the present invention is a second (quasi)metal oxide containing one or more second elements (M2) selected from the group consisting of Y, Hf, Ge, V, W, Al, Si, Mn, and Co.

[0064] This second metal oxide (M2) serves as a dopant to improve low-reflection and low-resistance characteristics, and the addition of the second metal oxide (M2) can simultaneously enhance the low-reflection and low-resistance characteristics of the tungsten oxide sintered body. The second metal oxide (M2) is not particularly limited as long as it is a component having a form in which oxygen is bonded to at least one element (A2) among Y, Hf, Ge, V, W, Al, Si, Mn, and Co, and may include, for example, one or more selected from the group consisting of Y2O3, HfO2, GeO2, WO3, V2O5, Al2O3, SiO2, MnO2, and Co3O4. Preferably, it may be WO3. In the following description, the second metal oxide component is symbolized and indicated as M2.

[0065] The second metal oxide may be included in an amount of 5 to 15 weight% based on 100 weight% of the sintered body, and specifically, 5 to 13 weight%.

[0066] The oxide sintered body comprising the aforementioned tungsten metal (M), first metal oxide (M1), and second metal oxide (M2) has a composition comprising 50 weight% or more of tungsten (M); 20 to 40 weight% of the first metal oxide (M1); and 5 to 15 weight% of the second metal oxide (M2), based on 100 weight% of the sintered body.

[0067] For example, the oxide sintered body may have (i) a weight% ratio of (M+M1) / (M1) of 2.0 to 4.5%, specifically 2.3 to 4.3%.

[0068] For another specific example, the oxide sintered body may have (ii) a weight percentage ratio of (M+M1+M2) / (M+M1) of 0.9 to 1.5%, specifically 1.0 to 1.3%.

[0069] The oxide sintered body of the present invention having the aforementioned composition comprises at least one crystalline phase.

[0070] Specifically, the sintered body is WM1 X O Y It may include a crystalline phase (11 < X < 27, 32 < Y < 78) and a tungsten metal crystalline phase. Such WM1 X O Y (11 < X < 27, 32 < Y < 78) The total ratio of the crystalline phase and tungsten metal is 50% or more with respect to 100% of the total compound phase contained in the sintered body, and specifically may be 53 to 63%. The above WM1 X O Y (11 < X < 27, 32 < Y < 78) An example of a crystal phase is WNb 12 O 33 There are others.

[0071] The oxide sintered body according to the present invention, configured as described above, has a relative density of 95% or more, specifically 98% or more, and the upper limit thereof is not particularly limited. In addition, the resistivity of the oxide sintered body is 3×10 -3 It is less than or equal to Ωcm, and the lower limit is not specifically restricted. And the average grain size (D) contained in the oxide sintered body. 50 The size of ) is not particularly limited and, for example, can be 1 to 30 μm, and specifically 5 to 20 μm.

[0072] In addition, a sputtering target according to another embodiment of the present invention comprises the aforementioned tungsten oxide sintered body; and a backing plate bonded to one surface of the sintered body to support the sintered body.

[0073] Here, the backing plate serves as a substrate supporting a sintered body for a sputtering target, and any conventional backing plate known in the art may be used without limitation. In this case, the material constituting the backing plate and its shape are not particularly limited.

[0074]

[0075] Method for manufacturing a tungsten-based oxide sintered body and a sputtering target

[0076] Hereinafter, a method for manufacturing an oxide sintered body and a sputtering target according to one embodiment of the present invention will be described. However, the method is not limited to the following manufacturing method, and the steps of each process may be modified or selectively combined as needed.

[0077] A preferred embodiment of the above manufacturing method may comprise: (i) a step of preparing a raw material powder comprising: a first metal oxide containing one or more first elements (M1) selected from the group consisting of tungsten, Nb, Ta, Zr, Ti, and Sn; and a second (quasi)metal oxide containing one or more second elements (M2) selected from the group consisting of Y, Hf, Ge, V, W, Al, Si, Mn, and Co; (ii) a step of manufacturing a molded body using the raw material powder; and (iii) a step of manufacturing a sintered body by sintering the molded body at 1,000 to 1,500°C for 0.5 to 3 hours.

[0078] The above manufacturing method is described below, divided into each process step.

[0079] (i) Powder mixing step

[0080] First, in the first step, a first metal oxide containing one or more first elements (M1) selected from the group consisting of tungsten, Nb, Ta, Zr, Ti, and Sn; and a second (mega)metal oxide containing one or more second elements (M2) selected from the group consisting of Y, Hf, Ge, V, W, Al, Si, Mn, and Co are weighed and mixed according to the desired chemical composition.

[0081] As a specific example of the first step above, tungsten (M), which is the main component for electrical properties, and a first metal oxide (M1) powder with excellent chemical resistance and heat resistance properties are added. At this time, the weight percentage ratio of (M+M1) / (M1) is 2.0 to 4.5%, specifically 2.3 to 4.3%, and more specifically 2.5 to 4.0%.

[0082] Next, a second metal oxide (M2) powder is added to the mixed raw material powder to improve low reflection and low resistance characteristics. At this time, the weight percentage ratio of (M+M1+M2) / (M+M1) is 0.9 to 1.5%, specifically 1.0 to 1.3%, more specifically 1.0 to 1.2%, and most specifically 1.0 to 1.17%.

[0083] After weighing, the mixed powder undergoes a dry ball milling process using zirconia balls.

[0084] Zirconia balls can be weighed in amounts ranging from 1 to 3 times the powder weight, and ball milling can be performed at a speed of 100 to 300 rpm for 7 to 9 hours, for example, 8 hours. After completing dry ball milling, the powder can be mixed by sieving.

[0085] (ii) Sintering step

[0086] In the second step, to sinter the mixed powder, a carbon sheet 0.1 to 0.5 mm thick is placed inside the carbon mold and the lower punch, and 300 to 500 g of the mixed powder is loaded. After loading the powder, the carbon sheet is placed over it and the upper punch is installed.

[0087] Once the preparation of the sintering mold is complete through this process, the sintering mold can be loaded into a hot press and the sintering process can be performed. During sintering, the heating rate can be set to 2 to 10°C / min, and the maximum heat treatment temperature can be maintained at 1,200 to 1,400°C for 1 to 3 hours. The pressure during heating and holding can be maintained at 17 to 30 MPa.

[0088] (iii) Processing step

[0089] In the third step, the sintered body is removed and processed after sintering is complete.

[0090] Specifically, after removing the sintered body, carbon sheets are removed from the upper and lower parts of the target, and then the surface of the target is polished. To remove the carbon sheets, the upper and lower parts can be machined to a thickness of at least 1 mm each.

[0091] (iv) Bonding step

[0092] In the fourth step, the processed sintered body is bonded to the backing plate.

[0093] Indium can be used as the adhesive, and it is desirable to ensure that the bonding rate is 95% or higher.

[0094] A metal oxide target can be manufactured through the aforementioned process. The target density of the manufactured target is 95% or higher, and specifically, it is desirable to have a density of 98.0% or higher.

[0095]

[0096] <Oxide Thin Film>

[0097] Another example of the present invention is a metal oxide thin film deposited using the aforementioned tungsten oxide-based target. Such a metal oxide thin film can be formed by performing sputtering using the aforementioned sintered body as a target material.

[0098] Although slight variations in composition may occur in the oxide thin film above depending on the deposition atmosphere, since it is manufactured by sputtering the aforementioned oxide target, its composition is substantially identical to that of the target. Accordingly, an oxide thin film having high density characteristics exceeding 95% relative density and low sheet resistance characteristics can be formed. In addition, at least two types of specific metal oxides are added to the main raw material, tungsten metal, within a predetermined range, and through compositional optimization, low reflection, low resistance, and heat resistance characteristics can all be improved.

[0099] For example, the oxide thin film may satisfy at least two of the following physical properties, and specifically, it is preferable to satisfy all of them.

[0100] For example, the average reflectance at a wavelength of 360 to 740 nm may be 25% or less, specifically 15% or less, and more specifically 12.5% ​​or less. Here, the measurement of reflectance may be performed according to methods known in the art. For example, the measurement may be taken on a substrate surface on which an oxide thin film is formed, and the optical reflectance for an average wavelength of 360 to 740 nm and / or a wavelength of 550 nm is measured. In this case, the lower limit of the optical reflectance is not particularly limited.

[0101] As another example, the sheet resistance of a thin film with a thickness of 100 to 500 Å is 3.0 × 10⁻⁶ 3 It is Ω / sq or less, specifically 2.0 × 10⁻⁶ 3 Ω / sq or less, more specifically 1.5 × 10⁻⁶ 3 It can be less than Ω / sq.

[0102] As another example, the average particle size of the crystalline phase included in the thin film may be 5 to 30 nm, and specifically 5 to 20 nm.

[0103] The tungsten oxide thin film according to the present invention can be formed (deposited) by a conventional sputtering method known in the art. At this time, sputtering can be performed using a DC sputter.

[0104] The above metal oxide thin film can be used as at least one of the gate layer, source layer, and drain layer of a thin film transistor (TFT). In addition, such a thin film transistor can be used in display devices such as OLED TVs, mobile phones, and tablets.

[0105] As a specific example, the metal oxide thin film according to an embodiment of the present invention can be used as an anti-reflection layer beneath the gate layer. A thin film for such an application lowers the reflectivity of the substrate and improves the adhesion of the gate electrode.

[0106] Here, the substrate may be any one of various substrates usable in conventional display device processes, such as a glass substrate, a metal substrate, a plastic substrate, or a plastic film. Specifically, the substrate may be a transparent front panel for an OLED TV, mobile phone, or tablet. Meanwhile, the gate electrode may be formed from a general electrode material such as copper or silver.

[0107] Thin film deposition uses a DC sputter power density of 1.0–2.5 w / cm² 2 The substrate can be operated at room temperature under an argon gas (Ar Gas) atmosphere. At this time, the thickness of the metal oxide thin film may be 300 to 500 Å, specifically 350 to 450 Å, but is not particularly limited thereto. Additionally, a copper (Cu) thin film may be deposited on the metal oxide thin film. At this time, the copper thin film may be deposited with a thickness of 3000 to 5000 Å. The average reflectance of the thin film deposited in this manner is measured on a glass surface.

[0108] Meanwhile, the measurement of reflectance may be performed according to methods known in the art. For example, the measurement may be performed on a substrate surface on which a metal oxide thin film is formed, and the light reflectance for an average wavelength of 360 to 740 nm and / or a wavelength of 550 nm is measured. In this case, the light reflectance may be 25% or less, specifically 15% or less, more specifically 12.5% ​​or less, and most specifically 12.0% or less, and the lower limit thereof is not particularly limited.

[0109] The metal oxide thin film according to an embodiment of the present invention has excellent heat resistance. The evaluation of such heat resistance can be performed as follows, but is not particularly limited thereto.

[0110] To evaluate the heat resistance of the thin film, a method of heat treating the thin film deposited as described above in an atmosphere of 200 to 400°C for 30 minutes or more can be used. The heat treatment can be performed in a general vacuum heat treatment furnace and / or a hydrogen heat treatment furnace, and for example, the heat resistance can be evaluated by observing the change in the characteristics of the thin film after heat treating it at a temperature of 200 to 400°C for 30 minutes or more in a hydrogen heat treatment furnace.

[0111] In addition, to evaluate chemical resistance, a method may be used in which a fine pattern is formed on the formed thin film using a lithography method and the cross-section of the formed fine pattern is observed.

[0112] The aforementioned oxide thin film can be used in various ways during the manufacture of semiconductor devices, for example, it can be applied for forming wiring or electrodes during semiconductor manufacturing. In particular, the metal oxide thin film can be used as at least one of the gate layer, source layer, and drain layer of a thin film transistor (TFT). When the thin film of the present invention is used as a barrier layer for the source and drain electrodes included in a thin film transistor, contact resistance can be lowered, and the physical properties of the thin film transistor can be improved by having excellent transparency and a low refractive index.

[0113] The tungsten oxide-based sputtering target and the oxide thin film formed therefrom according to the present invention described above simultaneously possess low reflection characteristics, low resistance characteristics, and excellent heat resistance characteristics, so the contact resistance with the TFT structure of LCDs and OLEDs or the electron injection layer of organic electroluminescent devices can be suppressed to a low level. Accordingly, the aforementioned oxide thin film can be applied without limitation to various display devices such as liquid crystal display devices or organic electroluminescent display devices, information transmission devices such as flat panel displays such as LCDs, PDPs, OLEDs, and LEDs; touch panels of surface light source illumination devices such as OLEDs and LEDs; mobile phones, tablets, and / or information transmission devices using the same.

[0114]

[0115] Thin film laminate

[0116] Another example of the present invention is a thin film laminate comprising at least two layers, including the aforementioned oxide thin film.

[0117] One or more thin films included in the above thin film laminate may include at least one of conventional metal thin films and metal oxide thin films known in the art, excluding the oxide thin films mentioned above. In addition, the number of layers or the shape of the thin film laminate is not particularly limited and may be a multilayer structure of 2 to 5 layers, specifically a thin film laminate of 2 to 4 layers. Such a multilayer thin film laminate may each include thin films of different components, or may be in a form in which 2 to 3 layers of thin films are stacked alternately.

[0118] In one specific example, the thin film laminate comprises: a transparent substrate; a tungsten oxide thin film formed on the transparent substrate; and a copper thin film formed on the tungsten oxide thin film; wherein the average reflectance at a wavelength of 360 to 740 nm measured at the transparent substrate side is 25% or less, and the sheet resistance at a thickness of 100 to 500 Å is 3.0 × 10⁻⁶ 3 It may be Ω / sq or less. Specifically, the average reflectance may be 15% or less, more specifically 12.5% ​​or less, where the lower limit is not specifically restricted. In addition, at a thin film thickness of 100 to 500 Å, the sheet resistance is 2.0 × 10⁻⁶ 3 Ω / sq or less, more specifically 1.5 × 10⁻⁶ 3 It may be less than or equal to Ω / sq, and the lower limit is not specifically restricted.

[0119] Here, the transparent substrate can be used as a substrate for the oxide thin film, and any ordinary substrate known in the industry can be used without limitation. For example, it may be a glass substrate, a plastic substrate, a plastic film, etc.

[0120] In addition, the copper thin film formed on the oxide thin film may be a TFT electrode provided in a display device, such as a source, drain, and / or gate electrode. However, it is not particularly limited thereto. Using a conventional metal thin film, a metal alloy thin film, and / or a metal oxide thin film instead of the aforementioned copper thin film is also within the scope of the present invention.

[0121] In the thin film laminate according to the present invention, the thickness ratio between the transparent substrate, the oxide thin film, and the copper thin film is not particularly limited and can be appropriately adjusted within the conventional range known in the art.

[0122] Furthermore, regarding oxide thin films and thin-film transistors and display devices to which they are applied, the descriptions provided above can be applied as is, so individual descriptions thereof are omitted.

[0123]

[0124] The present invention will be described in detail below through examples. However, the following examples are merely illustrative of the present invention, and the present invention is not limited by the following examples.

[0125]

[0126] [Example 1]

[0127] The powder was weighed so that the wt% ratio of (W+WO3+Nb2O5) / (W+WO3) was 1.51. After weighing the powder, it was placed in a 1L plastic container, and zirconia balls were added in a ratio of three times the powder volume. 3–10 mm zirconia balls were used. Once weighing was complete, dry mixing was performed in a ball mill at 170–230 rpm for 8 hours. The obtained dry powder was pressure-sintered using a hot press, with the internal vacuum condition of the press set to 10 -2 It was carried out at torr, with a heating rate of 3 to 7°C and a maximum temperature of 1200 to 1400°C, and a holding time of 1 to 3 hours, followed by furnace cooling.

[0128] The sintering density of the oxide sintered body obtained as described above is 98.8%, and the resistivity is 5.0 x 10⁻⁶ -3 It was measured in Ωcm.

[0129]

[0130] [Example 2]

[0131] The powder was weighed so that the wt% ratio of (W+GeO2+Nb2O5) / (W+GeO2) was 1.43. After weighing the powder, it was placed in a 1L plastic container, and zirconia balls were added in a ratio of three times the powder volume. 3–10 mm zirconia balls were used. Once weighing was complete, dry mixing was performed in a ball mill at 170–230 rpm for 8 hours. The obtained dry powder was pressure-sintered using a hot press, with the internal vacuum condition of the press set to 10 -2 It was carried out at torr, with a heating rate of 3 to 7°C and a maximum temperature of 1200 to 1400°C, and a holding time of 1 to 3 hours, followed by furnace cooling.

[0132] The sintering density of the oxide sintered body obtained as described above is 98.3%, and the resistivity is 7.0 x 10⁻⁶. -3 It was measured in Ωcm.

[0133]

[0134] [Comparative Example]

[0135] The powder was weighed so that the (Mo+MoO2+Nb2O5) / (Mo+MoO2) wt% ratio was 1.35. After weighing the powder, it was placed in a 1L plastic container, and zirconia balls were added in a ratio of three times the powder volume. 3–10 mm zirconia balls were used. Once weighing was complete, dry mixing was performed in a ball mill at 170–230 rpm for 8 hours. The obtained dry powder was pressure-sintered using a hot press, with the internal vacuum condition of the press set to 10 -2It was carried out at torr, with a heating rate of 3 to 7°C and a maximum temperature of 1200 to 1400°C, and a holding time of 1 to 3 hours, followed by furnace cooling.

[0136] The sintering density of the oxide sintered body obtained as described above is 97.5%, and the resistivity is 8.0 x 10⁻⁶. -3 It was measured in Ωcm.

[0137]

[0138] [Experimental Example: Evaluation of Thin Film Properties]

[0139] After forming a thin film using the sintered bodies prepared in Examples 1-2 and Comparative Examples as target materials, the physical properties of the thin film were evaluated as follows.

[0140] Specifically, a thin film serving as an anti-reflection layer beneath the gate layer was fabricated using each sintered body. This thin film is intended to improve anti-reflection and adhesion of the gate electrode on the substrate (glass).

[0141] The anti-reflection thin film was prepared by DC sputtering a target including the sintered bodies of Examples 1 and 2 and the Comparative Example, with a power density of 1.0 to 2.5 w / cm² 2 A thin film was formed by depositing it onto a transparent glass substrate under an argon gas atmosphere, with a thickness of 300–450 Å. Additionally, a gate electrode was formed on the aforementioned thin film. The gate electrode was formed using DC sputtering on a copper (Cu) target with a power density of 1.0–2.5 w / cm². 2 It was formed under an argon gas atmosphere and deposited with a thin film thickness of 3,000 to 5,000 Å.

[0142] Under these conditions, the average reflectance and sheet resistance were measured on the glass substrate surface and are shown in Table 1 and Figure 1 below, respectively.

[0143] Target Density Surface Resistance Low Reflection / Cu Thin Film Reflectance 360~740nm Average Reference Example 198.8% 0.925×10⁻⁶3 Ω / sq, 12.4% Example 298.3% 1.012×10⁻⁶ 3 Ω / sq, 11.8% Comparative Example 98.5% 3.500×10⁻⁶ 3 Ω / sq,11.6%

[0144] As shown in Table 1 above, the comparative example exhibited excellent reflectivity but poor sheet resistance. In contrast, it was found that low reflectivity and low resistance characteristics were simultaneously secured when using the tungsten oxide sintered bodies of Examples 1 and 2.

Claims

1. Tungsten (M); A first metal oxide containing one or more first elements (M1) selected from the group consisting of Nb, Ta, Zr, Ti, and Sn; and A second (quasi)metal oxide containing one or more second elements (M2) selected from the group consisting of Y, Hf, Ge, V, W, Al, Si, Mn, and Co; comprising A tungsten oxide sintered body comprising at least 50 weight% of tungsten (M) based on 100 weight% of the sintered body.

2. In Paragraph 1, The above tungsten (M) is a tungsten oxide sintered body containing 60 to 70 weight% based on 100 weight% of the sintered body.

3. In Paragraph 1, A tungsten oxide sintered body wherein the first metal oxide comprises one or more selected from the group consisting of Nb2O5, Ta2O5, ZrO2, TiO2, and SnO2.

4. In Paragraph 1, The above-mentioned first metal oxide is a tungsten oxide sintered body containing 20 to 40 weight percent based on 100 weight parts of the sintered body.

5. In Paragraph 1, The above second (quasi)metal oxide comprises one or more selected from the group consisting of Y2O3, HfO2, GeO2, WO3, V2O5, Al2O3, SiO2, MnO2, and Co3O4, forming a tungsten oxide sintered body.

6. In Paragraph 1, The above second metal oxide is a tungsten oxide sintered body containing 5 to 15 weight percent based on 100 weight parts of the sintered body.

7. In Paragraph 1, The above oxide sintered body is, (i) The weight percentage ratio of (M+M1) / (M1) is 2.0 to 4.5%, and (ii) A tungsten oxide sintered body having a weight% ratio of (M+M1+M2) / (M+M1) in the range of 0.9 to 1.5%.

8. In Paragraph 1, The above sintered body WM1 X O Y (11 <X<27, 32<Y<78) 결정상 및 텅스텐 금속 결정상을 포함하는 텅스텐 산화물 소결체 9. In Paragraph 1, Average grain size (D) constituting the above sintered body 50 ) is 1 to 30 μm, and Resistivity is 3×10 -3 It is less than or equal to Ωcm, and A tungsten oxide sintered body having a relative density of 95% or more.

10. A sputtering target comprising a tungsten oxide sintered body as described in any one of claims 1 to 9.

11. An oxide thin film formed from the sputtering target of claim 10.

12. In Paragraph 11, Oxide thin film with a thickness of 5 to 50 nm.

13. In Paragraph 11, The oxide thin film above satisfies at least two of the following physical properties: The average reflectance at wavelengths of 360 to 740 nm is 25% or less, and Sheet resistance is 3.0 × 10 at a thickness of 100 to 500 Å 3 It is Ω / sq or less, and The average particle size of the crystalline phase contained in the thin film is 5 to 30 nm.

14. Transparent substrate; An oxide thin film formed on the above-mentioned transparent substrate and described in claim 11; and A copper thin film formed on the oxide thin film; comprising The average reflectance at a wavelength of 360 to 740 nm measured on the transparent substrate side is 25% or less, and the sheet resistance at a thickness of 100 to 500 Å is 3.0 × 10⁻⁶ 3 Thin film laminate with Ω / sq or less.

15. Including the thin film of claim 11, A thin-film transistor in which the above-mentioned thin film is included as any one of a gate layer, a source layer, and a drain layer.

16. A display device comprising the thin film of claim 11.

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