Molybdenum oxide sintered body, sputtering target material, and oxide thin film

Abstract

Provided are: a sintered oxide having a molybdenum oxide as the main component; a sputtering target material comprising the sintered oxide; and an oxide thin film formed from the sputtering target material. In the present invention, a specific metal oxide is added to a molybdenum oxide and a niobium oxide that are difficult to sinter in a prescribed content range, and it is possible to simultaneously ensure improved sinterability, high density characteristics, and uniformity of a thin film obtained by controlling particle growth even when pressureless sintering is performed.

Description

TECHNICAL FIELD

[0001] The present application relates to a molybdenum-based oxide sintered body, a sputtering target comprising the same, and an oxide thin film formed by sputtering the target, and more particularly, to a molybdenum oxide-based sintered body, a sputtering target, and an oxide thin film formed by sputtering the target, which simultaneously improve sinterability and density characteristics by adding a specific metal oxide dopant in a prescribed content range when the target is used in the manufacture of a thin film transistor (TFT) structure of a liquid crystal display (LCD) and / or an organic light emitting diode (OLED). BACKGROUND

[0002] Generally, a low-reflectance conductive thin film is used in a flat panel display (FPD), a touch screen panel, a solar cell, a light emitting diode (LED), and an organic light emitting diode (OLED).

[0003] Among materials related thereto, an indium oxide-tin oxide (In2O3-SnO2) (indium tin oxide (ITO)) composition is used to form a conductive thin film having high visual light transmittance and electrical conductivity. Although such an indium tin oxide composition has excellent low-reflectance properties, it is economically low, and thus, research on materials that replace all or part of indium oxide has been conducted.

[0004] However, these studies only focus on the low reflectance of a thin film formed by a target, and thus, properties such as chemical resistance and heat resistance that can improve the reliability of a thin film during long-term use need to be considered.

[0005] On the other hand, molybdenum oxide itself is a difficult-to-sinter material. When such a difficult-to-sinter and low-density molybdenum oxide-based ceramic material is reused, not only is it difficult to form a high-density (for example, a relative density of 90% or more) target, but also when sputtering is performed using the prepared target, foreign matter is generated due to back deposition and nodules, and the like, and thus, the properties of a thin film are degraded.

[0006] PRIOR ART DOCUMENT

[0007] PATENT DOCUMENT

[0008] Patent Document 1: Korean Patent Publication No. 10-2020-0069314 SUMMARY

[0009] The present application is proposed to solve the aforementioned problems, and aims to provide a novel molybdenum oxide sintered body capable of improving and ensuring the density even when sintered in a pressureless state by adding a specific dopant to a molybdenum oxide having poor sinterability as a main raw material in a prescribed content range, a sputtering target including the sintered body, and an oxide thin film formed of the sintered body.

[0010] Other objects and advantages of the present application will be more clearly understood from the following detailed description of the application and the claims.

[0011] Technical Solution

[0012] To achieve the above technical problem, the present application provides an oxide sintered body including: molybdenum (M1); niobium (M2); at least one alkaline earth metal (M3); and zirconium (M4), containing 60 atomic percent or more of molybdenum (M1) as a main component based on 100 atomic percent of the total of the above metal components, and containing 0.1 atomic percent to 7 atomic percent of the above zirconium (M4) based on 100 atomic percent of the total of the above metal components.

[0013] In an embodiment of the present application, the oxide sintered body can contain at least one alkaline earth metal (M3) and the above zirconium (M4) in an atomic ratio of 1:0.03 to 0.54.

[0014] In an embodiment of the present application, the oxide sintered body can have an average particle diameter (D50) of 80% or less compared to the average particle diameter (D50) of an oxide sintered body not containing zirconium.

[0015] In an embodiment of the present application, the oxide sintered body can contain an MgZrNb2O8 crystal phase.

[0016] In an embodiment of the present application, the oxide sintered body can be pressurelessly sintered at atmospheric pressure after a formed body is prepared by mixing molybdenum (M1) oxide, niobium (M2) oxide, at least one alkaline earth metal (M3) oxide, and zirconium (M4) oxide.

[0017] In an embodiment of the present application, the molybdenum oxide (M1) can contain at least one of MoO2 and MoO3, and can contain 60 to 70 weight percent of the above molybdenum oxide (M1) with respect to the total weight of the oxide sintered body.

[0018] In one embodiment of the present application, the oxide sintered body can contain the molybdenum oxide (M1) and the niobium oxide (M2) in an amount of 85.0 wt% or more and less than 100 wt% based on 100 wt% of the oxide sintered body, and the content ratio of the molybdenum oxide (M1) to the niobium oxide (M2) can be 50:50 to 90:10 by weight.

[0019] In one embodiment of the present application, the metal oxide (M3) can include one or more selected from the group consisting of CaCO3 and MgO.

[0020] In one embodiment of the present application, the oxide sintered body can contain the alkaline earth metal oxide (M3) in an amount of more than 0 wt% and 10 wt% or less based on 100 wt% of the oxide sintered body.

[0021] In one embodiment of the present application, the oxide sintered body can contain one or more metals (M5) selected from the group consisting of molybdenum (Mo), titanium (Ti), chromium (Cr), tungsten (W), and copper (Cu).

[0022] In one embodiment of the present application, the oxide sintered body can contain the metal (M5) in an amount of 3 wt% to 50 wt% based on the total weight of the sintered body.

[0023] In one embodiment of the present application, the oxide sintered body for pressureless sintering can have an average particle diameter (D50) of 5 μm to 30 μm, a difference in surface roughness (Ra) before and after sputtering of the oxide sintered body can be 1.0 μm or less, and the specific resistance can be 1×10 -2 Ωcm or less, and the relative density can be 80% or more.

[0024] Also, the present application provides a sputtering target including the oxide sintered body.

[0025] Meanwhile, the present application provides an oxide thin film formed of the sputtering target.

[0026] Effects of the Invention

[0027] According to one embodiment of the present application, an auxiliary sintering property metal oxide dopant and a metal oxide dopant for controlling particle growth are added to a difficult-to-sinter molybdenum oxide in a prescribed content range, so that the sintering property of the molybdenum oxide sintered body can be improved even under pressureless conditions, and the optimization of particle size and high density can be ensured.

[0028] Accordingly, the molybdenum oxide sintered body and the sputtering target of the present application can be effectively used to form an electrode or a wiring line used in a thin film transistor structure of a liquid crystal display or an organic light emitting diode.

[0029] The effects of the present application are not limited to the above-described examples, and more various effects are included in the present specification. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A photograph showing the microstructure and average grain size of the oxide sintered body prepared in Example 1 to Example 4 in which zirconium oxide (M4) was added.

[0031] Figure 2 A photograph showing the microstructure and average grain size of the oxide sintered body prepared in Comparative Example 1 to Comparative Example 4 in which zirconium oxide (M4) was not added.

[0032] Figure 3 A graph showing the average particle diameter of the oxide sintered body subjected to pressureless sintering in Example 1 to Example 4 and Comparative Example 1 to Comparative Example 4.

[0033] Figure 4 A photograph of the appearance of the target after sputtering using the oxide sintered body target of Example 3 and Comparative Example 1.

[0034] Figure 5 A graph showing the change in relative density of the oxide sintered body prepared in Example 1 to Example 4 and Comparative Example 1 to Comparative Example 4 with respect to the sintering temperature.

[0035] Figure 6 A graph showing the change in shrinkage of the oxide sintered body prepared in Example 1 to Example 4 and Comparative Example 1 to Comparative Example 4 with respect to the sintering temperature.

[0036] Figure 7 A graph showing the change in mass loss rate of the oxide sintered body prepared in Example 1 to Example 4 and Comparative Example 1 to Comparative Example 4 with respect to the sintering temperature.

[0037] Figure 8 An X-ray diffraction (XRD) graph of the oxide sintered body prepared in Example 3, Comparative Example 1, and Comparative Example 3. DETAILED DESCRIPTION

[0038] All terms used in the present specification, including technical and scientific terms, can be used with the meanings commonly understood by those skilled in the art to which the present application pertains. Also, unless explicitly defined in particular or clearly understood from the context of the present description, terms commonly used in the art are not interpreted in an ideal or exaggerated sense.

[0039] In the present specification, when a certain part "comprises" a certain structural element, unless otherwise specifically stated, it means that other structural elements can also be included, not excluding other structural elements. Also, in the present specification, "upper" or "above" does not mean only a case where it is located above or below the object part, but also a case where other parts are included therebetween, and does not necessarily mean a case where it is located on the upper side based on the direction of gravity. Also, the terms "first", "second", and the like in the present specification do not mean any order or importance, but are used to distinguish each structural element.

[0040] Generally, a MoO2-Nb2O5 material for an existing n-type semiconductor thin film is prepared by a pressure sintering method. However, in the case of using the pressure sintering method, there is a limitation in mass production due to an increase in the cost of the preparation process due to equipment pressure. Also, the preparation process of applying high pressure has limitations in the size of the sintered body.

[0041] In order to solve the foregoing problems, when a pressureless sintering MoO2-Nb2O5 material is used, there is a limitation in the increase in sintering density, and in the case of increasing the sintering temperature, the amount of melting and volatilization increases, and on the contrary, a phenomenon of a decrease in density occurs. That is, heat is required as a driving force at the time of sintering, and generally, the higher the heat, the more advantageous it is to ensure sinterability (densification), but on the contrary, some element materials decrease the density due to volatilization and the like.

[0042] On the other hand, the present inventors confirmed in Korean Patent Application No. 10-2022-0132119 that, in a difficult-to-sinter material having molybdenum oxide and niobium oxide as basic components, a small amount of an auxiliary sintering alkaline earth metal oxide dopant (M3) is used, and even under atmospheric pressure conditions, pressureless sintering can simultaneously ensure the effects of improving sinterability and ensuring high density. In this case, the inter-particle bonding in the oxide sintered body can be ensured by adding the alkaline earth metal oxide (M3) dopant, but as a result, a phenomenon of an increase in the particle size in the sintered body occurs. In this case, in the sputtering process, the particles do not uniformly form a film, and ultimately, the quality of the oxide thin film is reduced and the reliability is reduced.

[0043] Therefore, in the present application, in a difficult-to-sinter material having molybdenum oxide (M1) and niobium oxide (M2) as basic components, an auxiliary sintering alkaline earth metal oxide dopant (M3) and a zirconium oxide (M4) for improving the uniformity of a thin film formed by sputtering by optimizing the particle size are used in combination, and by adjusting the composition thereof, not only a high-density target can be obtained due to the improvement in sinterability, but also a molybdenum oxide sintered body in which composition non-uniformity and impurities that can occur in the sputtering process are improved and a sputtering target using the same can be obtained by controlling the particle growth by adding the zirconium oxide (M4).

[0044] Oxide sinter and high-density target for sputtering

[0045] One example of the present invention is a metal oxide sinter for preparing a target for sputtering, which is mainly composed of molybdenum, and more particularly, a molybdenum-based oxide sinter used in a thin film transistor structure of a liquid crystal display and / or an organic light emitting diode and a high-density target for sputtering including the same.

[0046] In one example, the above oxide sinter includes: molybdenum (M1); niobium (M2); at least one alkaline earth metal (M3); and zirconium (M4), includes 60 atomic percent or more of molybdenum as a main component based on 100 atomic percent of the total of the above metal components, and includes the above zirconium (M4) in a prescribed atomic ratio (for example, 0.1 atomic percent to 7 atomic percent) in the above sinter based on 100 atomic percent of the total of the above metal components.

[0047] 0.001 ≤ M4 / (M1+M2+M3+M4) ≤ 0.07

[0048] Here, the total of 100 atomic percent of the metal components means that the sum of M1+M2+M3+M4 is 100 in the sinter, and the atomic ratio means that the sum of M1+M2+M3+M4 of a specific atom is 1. If necessary, the above atomic percent and atomic ratio can further include M5 and / or unavoidable impurities, in which case the above numerical values can be partially changed.

[0049] As described above, in the case of using at least one alkaline earth metal (M3) and zirconium (M4) dopant together, the problem of particle coarsening in the sinter caused by the addition of the alkaline earth metal (M3) type dopant is solved, so that the uniformity of the thin film formed by sputtering can be ensured by optimizing the particle size. Also, the sinterability of the existing molybdenum (M1), niobium (M2), and at least one alkaline earth metal (M3) based sinter, which is difficult to sinter, can be improved, and high-density characteristics can be ensured.

[0050] Hereinafter, each component will be described in detail.

[0051] The oxide sinter of the present invention includes molybdenum (M1) and niobium (M2) as basic components, and further includes at least one alkaline earth metal (M3) to assist sintering characteristics and zirconium (M4) to control particle growth as additional dopant components.

[0052] In one example, the molybdenum (M1) and niobium (M2) included in the above oxide sinter can satisfy the following atomic ratios, respectively.

[0053] (i) 0.85 ≤ (M1+M2) / (M1+M2+M3+M4) < 1.0; (ii) 0.5 ≤ M1 / (M1+M2) ≤ 0.9; (iii) 0.1 ≤ M2 / (M1+M2) ≤ 0.5, more specifically, (i) 0.90 ≤ (M1+M2) / (M1+M2+M3+M4) ≤ 0.995; (ii) 0.6 ≤ M1 / (M1+M2) ≤ 0.8; (iii) 0.2 ≤ M2 / (M1+M2) ≤ 0.4.

[0054] In another example, based on 100 atomic percent of the metal components included in the oxide sintered body described above, the alkaline earth metal (M3) included in the oxide sintered body can be greater than 0 atomic percent and less than or equal to 15 atomic percent, specifically, 3.0 atomic percent to 10 atomic percent, more specifically, 5.5 atomic percent to 7.5 atomic percent. At least one of the alkaline earth metals (M3) functions as a sintering aid, specifically, can include calcium (Ca), magnesium (Mg), or both. In the case of using calcium and magnesium in combination, the atomic ratio of calcium to magnesium in the oxide sintered body can be adjusted to 1:4 to 6, specifically, 1:4.5 to 5.5, more specifically, 1:5.

[0055] In another example, based on 100 atomic percent of the metal components included in the oxide sintered body described above, the zirconium (M4) included in the oxide sintered body can be 0.1 atomic percent to 7 atomic percent or less, specifically, 0.5 atomic percent to 5.0 atomic percent, more specifically, 1 atomic percent to 3 atomic percent.

[0056] In another example, the atomic ratio of the at least one alkaline earth metal (M3) to the zirconium (M4) included in the oxide sintered body described above can be 1:0.03 to 0.54, more specifically, 1:0.06 to 0.27. In the case of satisfying the aforementioned atomic ratio, it is possible to ensure the sintering characteristics and high density characteristics caused by the use of the alkaline earth metal (M3) dopant, and it is also possible to ensure the control effect caused by the use of the zirconium (M4) dopant.

[0057] In another example, the atomic ratio of the niobium (M2) to the zirconium (M4) included in the oxide sintered body described above can be 1:0.01 to 1.0, specifically, 1:0.05 to 0.5, more specifically, 1:0.05 to 0.2.

[0058] In another example, the oxide sintered body described above can further include one or more metals (M5) selected from the group consisting of molybdenum, titanium, chromium, tungsten, and copper. Preferably, molybdenum can be included. In this case, the content of the metal (M5) is not particularly limited and can be appropriately adjusted within the range of 100 atomic percent of the total of the metal components included in the oxide sintered body. As an example, 1 atomic percent to 50 atomic percent of the metal (M5) described above can be included, more specifically, 3 atomic percent to 50 atomic percent can be included, based on 100 atomic percent of the total of the technical components included in the oxide sintered body described above.

[0059] The oxide sintered body of the present application composed of the aforementioned composition not only has a fine average particle diameter (D50) compared to the existing sintered body not including zirconium (M4), but also has a small difference in surface roughness before and after sputtering of the sintered body target, thereby having uniform surface characteristics and excellent thin film characteristics.

[0060] In an example, the average particle diameter (D50) in the oxide sintered body described above can be 80% or less, specifically, 60% or less, more specifically, 40% to 50% compared to the average particle diameter (D50) in the oxide sintered body not including zirconium (M4). As an example, the average particle diameter (D50) of the oxide sintered body of the present application can be 5 μm to 30 μm, specifically, 10 μm to 20 μm. In comparison, the average particle diameter (D50) of the oxide sintered body not including zirconium (M4) can be 20 to 50 μm.

[0061] In another example, the difference in surface roughness (Ra) before and after sputtering of the oxide sintered body target described above can be 1.0 μm or less, more specifically, 0.7 μm or less. In this case, the target used in sputtering is 4 inches in size, is performed using a direct current power supply (DC power supply), is performed under process conditions of a working pressure (Working pressure) of 0.61 Pa, a power density (Power density) of 2.5 W / cm 2 , and a total consumption of the target of 8 kWh, which is based on 40 weight percent of the total weight of the target consumed.

[0062] Meanwhile, the oxide sintered body of the present application having the aforementioned composition includes one or more crystal phases, and in particular, is distinguished from the existing sintered body in that at least one crystal phase component necessarily includes zirconium (M4).

[0063] In another example, the oxide sintered body described above can include a MoO2 phase partially solid-solubilizing Nb2O5, for example, can include Mo 1-x Nb xO2(wherein, x is 0 to 0.25, specifically, 0.15 to 0.25) as a main crystal phase, can contain MgNb2O6, CaMo6O9 and / or MgZrNb2O8 as a sub-crystal phase. Also, the area ratio (specific area) of the MgZrNb2O8 crystal phase containing zirconium (M4) is not particularly limited, for example, with respect to the total crystal phase of the above sintered body, can contain 1% or more, more specifically, can contain in the range of 3% to 10%.

[0064] On the other hand, the oxide sintered body of the present application can contain a stoichiometric molybdenum oxide such as MoO2, MoO3, etc. as a final product, but substantially does not contain a sub-stoichiometric molybdenum oxide such as Mo4O 11 17 47 14 23 26 18 52 wherein "substantially does not contain" can mean that 2.0% by weight or less, specifically, 1.0% by weight or less, more specifically, 0.5% by weight or less of an unavoidable content is present with respect to 100% by weight of the above oxide sintered body.

[0065] The oxide sintered body of the present application can be formed by mixing oxides containing each metal component (M1, M2, M3, M4), for example, by mixing and preparing a molded body of a molybdenum (M1) oxide, a niobium (M2) oxide, an alkaline earth metal (M3) containing metal oxide and a zirconium (M4) oxide in a target composition, and then sintering at atmospheric pressure without pressure.

[0066] At present, when sintering an oxide sintered body, it is necessary to use heat or pressure as a driving force, and generally, the higher the heat and pressure, the more the sinterability of the sintered body is ensured, and the more advantageous it is for densification, and on the contrary, a part of the material is reduced in density due to problems such as melting and volatilization. In the present application, by adding an additional element (dopant), even if sintering is performed without pressure, it is possible to ensure the density (densification) of the sintered body that can be used as a target for sputtering, and by optimizing the particle size, it is possible to improve the uniformity of the thin film formed by sputtering.

[0067] wherein the molybdenum oxide is a main component constituting the sintered body.

[0068] ​​​​​​​The molybdenum oxide (Ml) is, for example, M0O2, M0O3, M0O4, or the like, and is a component having a form in which molybdenum is combined with oxygen. In the present application, M0O2, M0O3, or a mixture of M0O2 and M0O3 can be used as the molybdenum oxide (Ml). In this case, when a mixture of M0O2 and M0O3 is used as the molybdenum oxide, the mixing ratio between them is not particularly limited and can be appropriately adjusted within a range generally known in the technical field to which the present application pertains. On the other hand, M0O3 has a melting point of about 800°C and volatilizes at a high temperature of 1000°C or higher. Therefore, it is preferable to use M0O2 as the molybdenum oxide (Ml) in the present application in which pressureless sintering is performed at a high temperature of 1000°C or higher.

[0069] Further, the oxide sintered body of the present application contains, as one of the additive components, a niobium oxide (M2).

[0070] The above-mentioned niobium oxide (M2) is an oxide dopant for improving properties such as chemical resistance and heat resistance, and the chemical resistance and heat resistance and the like of the molybdenum oxide can be improved by adding the above-mentioned metal oxide. The above-mentioned niobium oxide is not particularly limited as long as it is a component having a form in which niobium is combined with oxygen, and can be, for example, Nb2Os. In the following description, the niobium oxide component is denoted as M2.

[0071] The other additive component contained in the oxide sintered body of the present application is a metal oxide (M3) containing at least one alkaline earth metal.

[0072] In one example, the above-mentioned metal oxide (M3) can contain at least one of barium (Ba), calcium (Ca), magnesium (Mg), and strontium (Sr), and specifically, can contain a metal oxide (M3) containing at least one of calcium and magnesium.

[0073] The metal oxide (M3) containing an alkaline earth metal functions as a dopant that assists the sinterability of the molybdenum oxide which is difficult to sinter, thereby exhibiting an effect of improving the density. The chemical resistance and heat resistance and the like of the molybdenum oxide can be improved by adding the above-mentioned metal oxide (M3). The above-mentioned metal oxide (M3) containing an alkaline earth metal is not particularly limited as long as it is a component having a form in which at least one element (A) of calcium and magnesium is combined with oxygen, and can contain, for example, one or more selected from the group consisting of CaCO3 and MgO.

[0074] One of the additive components contained in the oxide sintered body of the present application is a zirconium (M4) oxide.

[0075] In the past, when the density of the oxide sintered body is low (relative density ≤ 90%), foreign matter is generated in the thin film due to backside deposition and clumping when sputtering, and thus the higher the density, the more advantageous in the sputtering process. On the other hand, different particles on the surface of the target material are pulled out when sputtering. In this case, the position of the pull-out is left empty, and the smaller the particle, the smaller the position of the pull-out, thereby making the curvature of the sputtered target material surface smaller. Thus, the smaller the particle size of the oxide sintered body at the same density, the more uniform the film formation in the sputtering process, thereby ensuring the effect of improving the composition unevenness and foreign matter generation that can occur in the sputtering process.

[0076] The zirconium (M4) oxide used in the present application plays a role in improving the composition unevenness and foreign matter generation that can occur in the sputtering process by adjusting the growth of the particles constituting the oxide sintered body. The above-mentioned zirconium (M4) oxide is not particularly limited as long as it is a component having a zirconium and oxygen bonding form, and for example, can be ZrO2. In the following description, the zirconium oxide component is denoted as M4.

[0077] The aforementioned metal oxide sintered body containing the molybdenum (M1) oxide, the niobium (M2) oxide, the metal oxide containing at least one alkaline earth metal (M3), the zirconium (M4) oxide, and the metal (M5) oxide as necessary, based on 100 weight percent of the above-mentioned sintered body, can contain the molybdenum (M1) oxide and the niobium (M2) oxide in an amount of 85 weight percent or more and less than 100 weight percent, the alkaline earth metal (M3) type metal oxide in an amount of more than 0 weight percent and 10 weight percent or less, and the zirconium (M4) oxide in an amount of 0.1 weight percent to 10 weight percent. More specifically, it can have a composition of 85.0 weight percent to 99.5 weight percent of the molybdenum (M1) oxide and the niobium (M2) oxide, 0.5 weight percent to 5.0 weight percent of the alkaline earth metal (M3) type metal oxide, and 0.5 weight percent to 5.0 weight percent of the zirconium (M4) oxide.

[0078] The content ratio of the molybdenum oxide (M1) and the niobium oxide (M2) can be 50:50 to 90:10 by weight, specifically, 70:30 to 90:10 by weight, and more specifically, 75:25 to 90:10 by weight. In the present application, when the proportion of the molybdenum oxide is 60 weight percent or more, specifically, in the range of 60 weight percent to 70 weight percent, out of the total amount of the above-mentioned metal oxide sintered body, it can have a low reflection characteristic when deposited as a thin film.

[0079] The oxide sintered body of the present application can further contain one or more metals (M5) selected from the group consisting of molybdenum, titanium, chromium, tungsten, and copper, as necessary.

[0080] Such metal (M5) is a metal dopant that shows an effect of improving density by assisting sinterability of molybdenum oxide, and can improve chemical resistance and heat resistance of molybdenum oxide by adding the metal. Also, it can expand the range of application by reducing the sheet resistance per film due to high conductivity of the metal. Preferably, it is molybdenum. In the following description, one or more components among molybdenum, titanium, chromium, tungsten, and copper are marked as M5.

[0081] The above metal (M5) can be contained in an amount of 1.0 to 30.0% by weight, based on 100% by weight of the oxide sintered body. Specifically, the content of the metal (M5) can be in the range of 3.0 to 25.0% by weight, and more specifically, it can be 5.0 to 20.0% by weight.

[0082] Even if pressureless sintering is performed at atmospheric pressure, the relative density of the oxide sintered body of the present application configured as described above is 80% or more, and specifically, it can be 90% or more. In this case, the upper limit thereof is not particularly limited. Also, the specific resistance of the oxide sintered body is 1 x 10 -2 Ωcm or less, and the lower limit thereof is not particularly limited.

[0083] Also, the size (D50) of the grains contained in the oxide sintered body is not particularly limited, and for example, it can be 1 to 30 μm, specifically, it can be 3 to 30 μm, and more specifically, it can be 5 to 30 μm.

[0084] Also, in the case where a metal oxide sintered body configured by the aforementioned composition is used as a target to form a thin film, the thin film formed has low reflectance characteristics, and the heat resistance and chemical resistance are improved by optimization of the proportion and composition of molybdenum oxide. Also, density improvement can be achieved by adding a small amount of a specific dopant (M3), and pressure sintering can not be used, and a Mo-Nb-O sputtering target, which is a difficult-to-sinter material, can be prepared, and by adding zirconium (M4) oxide, the growth of particles in the sintered body is adjusted to a predetermined range, and thus uniformity and high quality of the thin film can be ensured.

[0085] Method of manufacturing oxide sintered body and sputtering target

[0086] Hereinafter, a method of manufacturing an oxide sintered body and a sputtering target according to an embodiment of the present application will be described. However, the manufacturing method is not limited to the following method, and each process step can be modified or the above process steps can be selectively mixed as needed.

[0087] The present application is a method for producing a sputtering target, i.e., a compact by heat-treating a raw material powder of a metal or a ceramic. For example, in the production of the oxide sintered body and the sputtering target described above, a raw material powder of a metal or a ceramic is prepared by using MoO2and / or MoO3, Nb2O5as a base material, adding an additional element, and mixing the same, and finally forming a sputtering target.

[0088] In one embodiment of the above production method, the following steps can be included: step (i) of preparing and mixing a raw material powder containing a molybdenum (M1) oxide, a niobium (M2) oxide, a metal oxide containing at least one alkaline earth metal (M3), and a zirconium (M4) oxide according to a target composition ("step S10"); step (ii) of producing a shaped body using the mixed raw material powder ("step S20"); and step (iii) of producing a sintered body by pressureless heat-treating the shaped body at a temperature of 1200 to 1600°C in a non-reactive gas atmosphere at atmospheric pressure for 1 to 20 hours ("step S30").

[0089] Hereinafter, the above production method will be described according to each step.

[0090] (i) Preparation of a raw material powder ("step S10")

[0091] The above step S10 is a step of preparing a raw material powder containing a molybdenum (M1) oxide, a niobium (M2) oxide, a metal oxide containing at least one alkaline earth metal (M3), and a zirconium (M4) oxide. Specifically, a molybdenum (M1) oxide, a niobium (M2) oxide, an alkaline earth metal (M3) oxide selected from one or more of the group consisting of CaCO3and MgO, a zirconium (M4) oxide powder, and a metal (M5) powder such as molybdenum, if necessary, are weighed according to a target composition, and the powders are put into a mixer, crushed, and mixed to prepare a mixture.

[0092] When the above raw material powder is mixed, a conventional additive known in the art, such as a binder, a dispersant, an antifoaming agent, and the like, can be further contained as needed. In this case, the amount of the additive used can be appropriately adjusted within a conventional range known in the art, for example, 0.01 to 10% by weight, with respect to the total weight of the powder in the slurry (e.g., 100% by weight).

[0093] The mixing and crushing of the raw material powder are not particularly limited, and can be performed using a conventional ball mill, a grinder, a bead mill, or the like known in the art. For example, the mixing and crushing of the raw material can be performed by a wet-type bead mill using zirconia balls, and then a powder spheroidization (spray dryer) operation is performed, and sieving is performed to obtain a final powder.

[0094] After putting in pure water and defoaming agent, plasticizer, binder, etc. corresponding to about 2 times the weight of the raw material powder, the mixing operation is performed for about 2 hours using a blender to mix thoroughly.

[0095] Then, 0.8Φ zirconia beads (about 2 kg) are put into a 1L-sized vessel made of zirconia, and the raw material mixed with pure water is put in to be thoroughly pulverized. In this case, the speed of the bead mill is not particularly limited, and for example, it can be about 2000 rpm to 4000 rpm, specifically, 2500 rpm to 3500 rpm, more specifically, about 3000 ± 200 rpm, 4 liters to 6 liters of raw material are put in per minute, specifically, 4.5 liters to 6.5 liters, more specifically, the raw material is put in at a speed of 5 liters per minute.

[0096] After thorough pulverization, a microspherical powder is prepared using a spray drying apparatus. Then, the sample powder is separated from the waste powder using a 90 mesh to 110 mesh, specifically, a 100 mesh screen as needed.

[0097] (ii) Preparation of a shaped body ("Step S20")

[0098] The above step S20 is a step of preparing a shaped body using the prepared raw material powder, and more specifically, the raw material powder is put into a molding machine to be subjected to a molding process to prepare a shaped body of a prescribed specification.

[0099] In order to improve the density of the shaped body, the molding process is performed once or more, and specifically, it can be performed twice. For example, the primary molding process is performed by putting the raw material powder into a single-axis molding machine to prepare a primary shaped body, and the secondary molding process can be performed using a cold isostatic press (CIP).

[0100] The conditions of the above primary molding process are not particularly limited, and can be appropriately adjusted within the usual conditions known in the art to which the present application pertains. For example, the primary shaped body is prepared using a 50Φ-specification superhard material mold according to the fixed weight of the powder. In this case, the primary molding can be performed at the minimum pressure required for the shape to be formed, and specifically, it can be performed at a pressure of about 10 MPa for about 1 minute. Then, the secondary molding is performed using cold isostatic pressing (CIP) under the conditions of 200 MPa for several hours. In this case, since the organic solvent including water is used when the secondary cold isostatic pressing is performed, it can be performed in a state of being put into an acrylic sealing material (e.g., a bag).

[0101] (iii) Preparation of a sintered body ("Step S30")

[0102] In the above step S30, a sintered body is prepared by sintering the prepared shaped body under prescribed conditions.

[0103] In this case, the sintering conditions are not particularly limited and can be appropriately adjusted within the general conditions known in the art to which the present application pertains. For example, pressureless sintering can be performed at a temperature of 1200°C to 1600°C for 1 hour to 20 hours, specifically, for 1 hour to 4 hours. The sintering described above can be performed in an oxygen atmosphere or under non-reactive gas conditions.

[0104] As a specific example of the above step S30, the prepared shaped body is put into an alumina crucible of a prescribed size and sintered. In the present experiment, in order to confirm the differences in characteristics between the shaped body before heat treatment and the pressureless sintered body after heat treatment, various physical properties were compared by measuring the weight, diameter, height, etc. of the respective shaped body and sintered body (see Tables 1-2 below and the like). Figures 4 to 6 ).

[0105] The relative density of the pressureless sintered body prepared by this process can be 80% or more, specifically, 85% or more, and more specifically, 90% or more. In this case, the upper limit is not particularly limited.

[0106] (iv) Preparation of a sputtering target

[0107] Next, the sintered body on which sintering is completed is taken out and processed. For example, after taking out the sintered body obtained after heat treatment, in order to perform grinding processing on the surface of the target, 1 mm or more can be processed on the upper and lower portions of the target, respectively.

[0108] Then, a productized sputtering target is prepared by diffusion bonding and final processing known in the art to which the present application pertains.

[0109] Specifically, the sintered body obtained in the above step S30 is bonded to a backing plate. In this case, indium can be used as the bonding agent, and it is preferable that the bonding rate be 95% or more. Next, processing equipment is used to process to the final target thickness, and the final sputtering target is obtained by performing bead blasting and / or arc spray processing on the surface of the backing plate.

[0110] A metal oxide target can be prepared by the above process. The target density of the prepared target is 90% or more, specifically, preferably 95% or more.

[0111] Oxide thin film

[0112] Another example of the present application is a metal oxide thin film deposited using the above molybdenum oxide-based target. Such a metal oxide thin film can be formed by sputtering using the above sintered body as a target.

[0113] The oxide film can have a slight difference in composition depending on the deposition atmosphere, but is actually the same as the composition of the oxide target since it is prepared by sputtering the oxide target. Therefore, an oxide film having a relative density of 80% or more and an excellent specific resistance of 1 x 10 -2 Ωcm or less can be formed. Also, by adding a metal oxide and a metal in a prescribed range to the molybdenum oxide as a main raw material, the chemical resistance, heat resistance, and other properties can be improved by optimizing the ratio and composition of the molybdenum oxide.

[0114] The metal oxide film of the present application can be formed (deposited) using a conventional sputtering method known in the art to which the present application pertains. As an example of the above-mentioned preparation method, a step of depositing at room temperature under an oxygen and / or argon atmosphere in a vacuum chamber after installing the sintered molybdenum oxide sputtering target is included. In this case, sputtering can be performed using a DC sputter machine.

[0115] The substrate and sputtering device used can be used without limitation using conventional substrates and sputtering devices known in the art to which the present application pertains. Specifically, it is formed by supplying oxygen, oxygen and high-purity argon at a rate of 80 to 110 seem (standard cubic centimeters per minute) in a vacuum chamber, specifically, at a rate of 95 to 105 seem, and deposition can be performed at room temperature (RT) without heating the substrate on which the film is formed. Also, the power density of the DC sputter machine can be 1.0 to 2.0 W / cm 2 The thickness of the metal oxide film can be to but is not limited thereto.

[0116] The oxide film obtained as described above can be used in various ways when preparing a semiconductor device, for example, it can be used to form a line or to form an electrode when preparing a semiconductor. In particular, the above-mentioned metal oxide film can be used in at least one of the gate layer, the source layer, and the drain layer of a thin film transistor. When the film of the present application is used in the barrier layer of the source layer and the drain layer included in the thin film transistor, the contact resistance can be reduced, the transparency is excellent, and the film has a low refractive index, so that the physical properties of the thin film transistor can be improved.

[0117] The aforementioned molybdenum oxide sputtering target of the present application and the oxide thin film formed therefrom have high density and excellent specific resistance characteristics even under no pressure, and can suppress low contact resistance in a thin film transistor structure of a liquid crystal display and an organic light emitting diode or an electron injection layer of an organic electroluminescent device. Accordingly, the aforementioned oxide thin film can be applied without limitation to various display devices such as a liquid crystal display device or an organic electroluminescent display device, for example, a liquid crystal display, a plasma display panel (PDP), an organic light emitting diode, a light emitting diode (LED), and the like, information transmission devices such as a flat panel display, an organic light emitting diode, a light emitting diode, and the like, a touch panel of a surface light source illumination device, a mobile phone, a tablet, and / or an information transmission device using the same.

[0118] Hereinafter, the present application will be described in detail by way of examples. However, the following examples are merely illustrative of the present application and the present application is not limited to the following examples.

[0119] Examples 1-4: Preparation of sintered bodies added with MoO2-Nb2O5 and ZrO2

[0120] A molding body was prepared by mixing molybdenum (M1) oxide, niobium (M2) oxide, alkaline earth metal (M3) metal oxide, zirconium (M4) metal oxide, and optionally metal (M5) in the proportions shown in Table 1 below.

[0121] The molding body was prepared in most of the samples to be 50Φ. Then, the oxide sintered body of Examples 1 to 4 was prepared by heat treating in a nitrogen atmosphere at a temperature of about 1400 to 1500°C for 2 hours using a heat treatment apparatus.

[0122] Table 1

[0123]

[0124] Comparative Examples 1-4: Preparation of sintered bodies added with MoO2-Nb2O5 and α

[0125] A molding body of 50Φ was prepared in the same manner as in the above examples except for changing the composition shown in Table 1 above. Then, the sintered body of Comparative Examples 1 to 4 was prepared by heat treating in a nitrogen atmosphere at a temperature of about 1400 to 1500°C for 2 hours using a heat treatment apparatus.

[0126] Experimental Example 1: Evaluation of physical properties of molding bodies

[0127] The physical properties of each of the molding bodies prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated in the following manner.

[0128] Specifically, the diameter (D) and height (T) of each shaped body were measured using a vernier caliper, and the weight (Mass) was measured using a scale. Also, the relative density was calculated by converting the amount of addition of each weight to a volume percentage and converting the level compared to the theoretical density to a percentage, and the results are shown in Table 2. The density of the measured sample was calculated as weight / volume, and when multiple identical samples were prepared, the average value was represented.

[0129] For reference, each sample in Table 2 below had a low relative density because sintering was not performed, and the relative density of each sintered body after sintering (heat treatment) exhibited a level of 96%.

[0130] Table 2

[0131]

[0132] Experimental Example 2: Evaluation of microstructure change and average particle diameter of sintered body

[0133] The microstructure change and average particle diameter of the sintered body heat-treated at a temperature of 1437℃ were evaluated, respectively.

[0134] Specifically, the sintered bodies of Examples 1 to 4 prepared under pressureless conditions and Comparative Examples 1 to 3 prepared under the same conditions were used as samples. The two samples were cut into a size of 10x10x10mm using a blade of a metal material, and then polished using a polisher from SiC paper #100 to #2000 for several minutes, and then finally using a paste of 1μm and a very fine fiber cloth. Then, the sample was immersed in hydrogen peroxide at a temperature of about 200℃ for 1 minute and heat-treated so that the surface of the microstructure could be exposed.

[0135] Also, for the measurement of the average particle diameter of the sintered body, each sample was observed at the same magnification of 1000 times using an FE-SEM (Hitachi, S-4800), 5 lines were randomly drawn on the measured image, and about 100 particles were calculated using a linear fitting method (Linear intercept method) according to Mathematical Formula 1 below, and the results are shown in Table 3. Figures 1 to 3

[0136] Mathematical Formula 1

[0137] D = 1.56 x C / MN

[0138] In the above formula, D = average particle diameter, C = total length of line, M = magnification, and N = number of particles on the line.

[0139] ​The experimental results show that, in the case of Comparative Example 1 in which molybdenum oxide and niobium oxide are used, the average particle diameter of the sintered body is about 11.8 μm. Also, in the case of Comparative Example 3 in which molybdenum oxide and niobium oxide are used as the basic components and an alkaline earth metal oxide is further included, the average particle diameter is 27.2 μm, and it is known that the average particle diameter of the sintered body is slightly increased due to the alkaline earth metal dopant.

[0140] In contrast, in the case of Examples 1 to 4 in which molybdenum oxide and niobium oxide are used as the basic components and an alkaline earth metal oxide and zirconium oxide are further included, it is confirmed that the average particle diameter is smaller than that of Comparative Example 3 (see Table 3). Figures 1 to 3

[0141] Experimental Example 3: Evaluation of the appearance of the sintered body after sputtering

[0142] The appearance of the sintered body target after sputtering was evaluated using the sintered body targets of Example 3 and Comparative Example 3, and the results are shown in Table 3 and Figure 4

[0143] Generally, if the surface roughness (Ra) of the sputtering target is high, problems such as impurity contamination, unevenness of the film composition, etc. are caused.

[0144] The experimental results show that the surface roughness of the sintered body target of Comparative Example 3, which does not include zirconium, is 0.59 μm before sputtering, and the surface roughness of the target after sputtering is 4.9 μm. In contrast, the surface roughness of the sintered body target of Example 3 is 0.53 μm, and the surface roughness of the target after sputtering is 0.82 μm.

[0145] From the above results, it is confirmed that the oxide sintered body of the present application controls the particle growth in the sintered body caused by the alkaline earth metal (M3) dopant to be within a prescribed range by adding the zirconium (M4) dopant, thereby exerting the effects of uniformization of the composition and improvement of the film quality.

[0146] Table 3

[0147]

[0148] [Experimental Example 4: Evaluation of the density and shrinkage of the sintered body

[0149] After heat treatment of each sample prepared in Examples 1 to 4 and Comparative Examples 1 to 3, the change in the physical properties of each sintered body was measured.

[0150] (1) Evaluation of the density after heat treatment

[0151] The physical properties of the sintered body after heat treatment were evaluated by measuring the diameter, height, and weight of the sintered body after heat treatment in the same manner as in Experimental Example 1 above. For example, the results of the relative density calculated by measuring the diameter, height, and weight of the sintered body after heat treatment are shown in Table 4. Figure 4 ​​shown.

[0152] The experimental results show that in Examples 1 to 4, the relative density significantly increases as the sintering temperature increases from 1400°C to 1500°C (see Figure 5 ). In contrast, in Comparative Examples 1 to 2, the relative density of the shaped bodies is lower or similar as the sintering temperature, while Comparative Example 3 has a similar density to the Examples.

[0153] (2) Evaluation of shrinkage before and after heat treatment

[0154] The shrinkage was calculated by measuring the diameter and height of the shaped body before heat treatment and the sintered body after heat treatment, respectively. The calculated shrinkage results are shown in Figure 6 .

[0155] The experimental results show that in Comparative Examples 1 to 3, the shrinkage after heat treatment varies little. In contrast, it is known that in Examples 1 to 4, the sintered body has a relatively large variation in shrinkage after heat treatment (see Figure 6 ). Such a high shrinkage before and after heat treatment indicates that most of the pores present in the shaped body are removed by heat treatment, and as a result, it is known that the density and density characteristics of the sintered body are significantly improved by heat treatment.

[0156] Experimental Example 5: Evaluation of the density and mass reduction of the sintered body

[0157] After heat treatment of each shaped body sample prepared in Examples 1 to 4 and Comparative Examples 1 to 4, the mass change of each sintered body was measured.

[0158] When measuring the mass change, the weight before sintering was measured, and the weight after removal was measured and the mass loss value was converted to a percentage, and the results are shown in Figure 7 .

[0159] The experimental results show that in Examples 1 to 4, the mass change reduction rate of the sintered body after heat treatment is relatively large compared to Comparative Examples 1 to 4. (see Figure 7 ).

[0160] Experimental Example 6: Evaluation of the specific resistance of the sintered body

[0161] The specific resistance characteristics were evaluated for each sintered body sample prepared in Examples 1 to 4 and Comparative Examples 1 to 4.

[0162] Specifically, the specific resistance of the sintered body samples of Examples 1 to 4 and Comparative Examples 1 to 4 was measured using the Loresta-GX MCP-T700 product (Mitsubishi chemical), and the results are shown in Table 4 below.

[0163] Table 4

[0164]

[0165] As shown in Table 4 above, it was confirmed that the sintered bodies of Examples 1 to 4, which contain the prescribed metal oxide as an additive, have excellent specific resistance characteristics compared to the sintered bodies of Comparative Examples 1 to 4, which do not contain a specific dopant additive.

[0166] Experimental Example 7: X-ray Diffraction Evaluation of Sintered Body

[0167] In order to confirm the crystallinity of the oxide sintered bodies of Example 3, Comparative Example 1, and Comparative Example 3, X-ray diffraction analysis was performed, and the results are shown in FIG. 3. Figure 8

[0168] It was confirmed that the oxide sintered body of Example 3 additionally generates the MgZrNb2O8phase, unlike Comparative Example 1 and Comparative Example 3, which do not contain zirconium, and it was judged that the average grain size of the grains was thus reduced by reducing the movement of the particles within the sintered body (see FIG. 3). Figure 8 )​

Claims

1. An oxide sintered body, comprising: Molybdenum M1; Niobium M2; At least one alkaline earth metal M3; and Zirconium M4, Based on a total atomic percentage of 100 for the aforementioned metallic components, molybdenum M1, containing at least 60 atomic percentages, is the main component. The above-mentioned oxide sintered body is characterized in that, Based on a total of 100 atomic percentages of the aforementioned metal components, the aforementioned zirconium M4 comprises 0.1 atomic percentages to 7 atomic percentages.

2. The oxide sintered body according to claim 1, characterized in that, It contains at least one alkaline earth metal M3 and zirconium M4 in an atomic ratio of 1:0.03 to 0.

54.

3. The oxide sintered body according to claim 1, characterized in that, The average particle size D50 of the oxide sintered body is less than 80% of that of the oxide sintered body without zirconium.

4. The oxide sintered body according to claim 1, characterized in that, The molybdenum M1 and niobium M2 contained in the above-mentioned oxide sintered body satisfy the following atomic ratio: (i)0.85≤(M1+M2) / (M1+M2+M3+M4)<1.0, (ii) 0.5 ≤ M1 / (M1+M2) ≤ 0.9, (iii)0.1≤M2 / (M1+M2)≤0.

5.

5. The oxide sintered body according to claim 1, characterized in that, The above-mentioned niobium M2 and zirconium M4 are contained in an atomic ratio of 1:0.01 to 1.

0.

6. The oxide sintered body according to claim 1, characterized in that, The above-mentioned alkaline earth metal M3 includes at least one element selected from calcium and magnesium.

7. The oxide sintered body according to claim 1, characterized in that, The aforementioned oxide sintered body also contains one or more metals M5 selected from the group consisting of molybdenum, titanium, chromium, tungsten and copper.

8. The oxide sintered body according to claim 1, characterized in that, The aforementioned oxide sintered body contains a MgZrNb2O8 crystalline phase.

9. The oxide sintered body according to claim 1, characterized in that, The above-mentioned oxide sintered body is formed by mixing molybdenum M1 oxide, niobium M2 oxide, at least one alkaline earth metal M3 oxide and zirconium M4 oxide to prepare a shaped body, and then sintering it under atmospheric pressure without pressure.

10. The oxide sintered body according to claim 9, characterized in that, The aforementioned molybdenum oxide M1 contains at least one of MoO2 and MoO3. The above-mentioned molybdenum oxide M1 comprises 60 to 70% by weight relative to the total weight of the oxide sintered body.

11. The oxide sintered body according to claim 9, characterized in that, Based on a sintered body of the aforementioned oxides comprising 100% by weight, the sintered body contains at least 85.0% by weight and less than 100% by weight of the aforementioned molybdenum oxide M1 and niobium oxide M2. The content ratio of the above molybdenum oxide M1 to the above niobium oxide M2 ​​is 50:50 to 90:10 by weight.

12. The oxide sintered body according to claim 9, characterized in that, The aforementioned alkaline earth metal oxide M3 includes one or more of the groups selected from CaCO3 and MgO.

13. The oxide sintered body according to claim 9, characterized in that, Based on 100% by weight of the above-mentioned oxide sintered body, it contains more than 0% by weight and less than or equal to 10% by weight of the above-mentioned alkaline earth metal oxide M3.

14. The oxide sintered body according to claim 9, characterized in that, The aforementioned oxide sintered body also contains one or more metals M5 selected from the group consisting of molybdenum, titanium, chromium, tungsten and copper.

15. The oxide sintered body according to claim 14, characterized in that, Based on the total weight of the sintered body, it contains 3% to 50% of the aforementioned metal M5.

16. The oxide sintered body according to claim 9, characterized in that, The average particle size D50 of the oxide sintered body constituting the above-mentioned pressureless sintering is 5 μm to 30 μm. The surface roughness Ra difference between the oxide sintered body before and after sputtering is less than 1.0 μm. The specific resistance is 1×10 -2 Below Ωcm, The relative density is over 80%.

17. A sputtering target, characterized in that, It comprises an oxide sintered body according to any one of claims 1 to 16.

18. An oxide thin film, characterized in that, Formed from the sputtering target as described in claim 17.

19. A method for preparing an oxide sintered body according to claim 1, characterized in that, include: Step (i) involves preparing and mixing a raw material powder containing molybdenum oxide M1, niobium oxide M2, a metal oxide M3 containing at least one alkaline earth metal, and zirconium oxide M4 according to the target composition. Step (ii) involves preparing a molded body using the mixed raw material powders; as well as Step (iii): The above-mentioned molded body is prepared by pressureless heat treatment at atmospheric pressure in an inactive gas atmosphere at a temperature of 1200 to 1600°C.

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