WO2020170949A1

WO2020170949A1 - Oxide sintered body, sputtering target, and method for producing sputtering target

Info

Publication number: WO2020170949A1
Application number: PCT/JP2020/005666
Authority: WO
Inventors: 暁海上
Original assignee: 出光興産株式会社
Priority date: 2019-02-18
Filing date: 2020-02-13
Publication date: 2020-08-27
Also published as: JP7359836B2; CN113423860A; JPWO2020170949A1; KR20210129040A; TW202041483A

Abstract

An oxide sintered body (1) in which the average value of the Vickers Hardness values of the surface of the oxide sintered body (1) is 500 to 900 Hv exclusive.

Description

Oxide sintered body, sputtering target, and method for manufacturing sputtering target

The present invention relates to an oxide sintered body, a sputtering target, and a method for manufacturing a sputtering target.

Conventionally, in a display device such as a liquid crystal display or an organic EL display driven by a thin film transistor (hereinafter referred to as “TFT”), an amorphous silicon film or a crystalline silicon film is mainly used as a channel layer of the TFT. It was
On the other hand, in recent years, oxide semiconductors have been attracting attention as a material used for a channel layer of a TFT with a demand for higher definition of a display.

Among the oxide semiconductors, an amorphous oxide semiconductor containing indium, gallium, zinc, and oxygen (In—Ga—Zn—O, abbreviated as “IGZO” hereinafter) has high carrier mobility and thus is preferable. It is used. However, IGZO has a drawback that the raw material cost is high because In and Ga are used as raw materials.

From the viewpoint of reducing the raw material cost, Zn—Sn—O (hereinafter abbreviated as “ZTO”) or In—Sn—Zn—O in which Sn is added instead of Ga of IGZO (hereinafter abbreviated as “ITZO”). Yes.) is proposed.
Since ITZO exhibits much higher mobility than IGZO, ITZO is expected as a next-generation oxide semiconductor material that is advantageous for downsizing TFTs and narrowing the frame of panels.

However, since ITZO has a large thermal expansion coefficient and a low thermal conductivity, there is a problem that cracks are likely to occur due to thermal stress during bonding to a backing plate such as Cu or Ti and during sputtering.
In recent studies, it is reported that reliability, which is the greatest problem of oxide semiconductor materials, can be improved by densifying the film.
High power film formation is effective for densifying the film. However, in a large-scale mass production apparatus, cracking of the end portion of the target on which plasma is concentrated poses a problem, and particularly the ITZO-based material target tends to crack easily.

For example, Non-Patent Document 1 describes that in ceramics, Vickers hardness and tensile strength are in a proportional relationship.

In Patent Document 1, zinc oxide, tin oxide, and an oxide of at least one metal (M metal) selected from the group consisting of Al, Hf, Ni, Si, Ga, In, and Ta are mixed. And an oxide sintered body obtained by sintering, which has a Vickers hardness of 400 Hv or more. Patent Document 1 describes that nodule is unlikely to occur even when a film is formed by using a DC sputtering method using such an oxide sintered body, and stable discharge is possible for a long time. ..

Japanese Patent Laid-Open No. 2012-180247

Although Patent Document 1 describes that the Vickers hardness of a sputtering target containing an oxide sintered body is defined within a predetermined range, the Vickers hardness in Patent Document 1 shows that the oxide sintered body is t/2. It is a value obtained by measuring the position of the surface of the cut surface cut at (t: thickness). Therefore, Patent Document 1 does not describe the Vickers hardness on the surface of the oxide sintered body.
In recent years, there has been a demand for a target having improved crack resistance during sputtering, but Patent Document 1 describes that the generation of nodules is suppressed by controlling the hardness of the oxide sintered body. However, it does not describe a method for improving crack resistance. Further, although Patent Document 1 describes that the sintering conditions and the subsequent heat treatment conditions are appropriately controlled in order to control the hardness of the oxide sintered body, the conditions described in Patent Document 1 do not apply. , It is difficult to improve crack resistance.

An object of the present invention is to provide an oxide sintered body and a sputtering target having improved crack resistance, and a method for manufacturing the sputtering target.

[1A]. An oxide sintered body, wherein the average value of the Vickers hardness of the surface of the oxide sintered body is more than 500 Hv and less than 900 Hv.

[2A]. A sputtering target containing the oxide sintered body according to [1A].

[1]. A sputtering target including an oxide sintered body, wherein the average value of the Vickers hardness of the surface of the oxide sintered body is more than 500 Hv and less than 900 Hv.

[2]. The sputtering target according to [1] or [2A], wherein the oxide sintered body contains an indium element, a tin element, and a zinc element.

[3]. In the sputtering target according to [2], the oxide sintered body further contains an X element, and the X element is a germanium element, a silicon element, a yttrium element, a zirconium element, an aluminum element, a magnesium element, a ytterbium element, and A sputtering target, which is at least one element selected from the group consisting of gallium elements.

[4]. The sputtering target according to [2] or [3], wherein the oxide sintered body satisfies the atomic composition ratio range represented by the following formulas (1), (2), and (3).
0.40≦Zn/(In+Sn+Zn)≦0.80 (1)
0.15≦Sn/(Sn+Zn)≦0.40 (2)
0.10≦In/(In+Sn+Zn)≦0.35 (3)

[5]. In the sputtering target according to any one of [2] to [4],
The oxide sintered body is a sputtering target containing a hexagonal layered compound represented by In ₂ O ₃ (ZnO)m [m=2 to 7] and a spinel structure compound represented by Zn ₂ SnO ₄ .

[5A]. The oxide sintered body is a hexagonal layered compound represented by In ₂ O ₃ (ZnO)m [m=2 to 7] and Zn _2-x Sn _1-y In _x+y O ₄ [0≦x<2. Including a spinel structure compound represented by 0≦y<1],
The sputtering target according to any one of [2] to [4]

[6]. A method for manufacturing a sputtering target for manufacturing the sputtering target according to any one of [1] to [5], [2A] and [5A],
A step of granulating the raw material of the oxide sintered body to obtain a raw material granulated powder having a particle size of 25 μm or more and 150 μm or less;
A step of filling the raw material granulated powder in a mold and molding the raw material granulated powder filled in the mold to obtain a molded body;
Sintering the molded body at 1310° C. or higher and 1440° C. or lower,
Manufacturing method of sputtering target.

[7]. The method for manufacturing a sputtering target according to [6], wherein the raw material granulated powder has a particle size of 25 μm or more and 75 μm or less.

According to one aspect of the present invention, an oxide sintered body and a sputtering target with improved crack resistance can be provided.
According to one aspect of the present invention, a method of manufacturing a sputtering target according to one aspect of the present invention can be provided.

It is a perspective view which shows the shape of the target which concerns on one Embodiment of this invention. It is a perspective view which shows the shape of the target which concerns on one Embodiment of this invention. It is a perspective view which shows the shape of the target which concerns on one Embodiment of this invention. It is a perspective view which shows the shape of the target which concerns on one Embodiment of this invention. It is a SEM observation image of the raw material granulated powder prepared in the Example. It is an XRD chart of the oxide sinter which concerns on an Example.

The crack of the sputtering target is generated from a weak portion of the target as a starting point.
Therefore, the inventor of the present invention has considered reducing the variation in strength in the plane of the sputtering target, particularly improving the minimum strength, as a measure for improving the crack resistance.
The present inventor, as a result of diligent examination of the manufacturing conditions of the sputtering target, by optimizing the particle size of the raw material granulated powder and the sintering temperature, the minimum value of the Vickers hardness on the sputtering surface of the oxide sintered body is improved. However, it was found that the average value is improved.
Further, it was also found that the average value of the Vickers hardness in the oxide sintered body has an optimum range, and if the Vickers hardness is too high, microcracks are generated in the target grinding step, and the crack resistance is reduced.
The present inventor invented the present invention based on these findings.

Hereinafter, embodiments will be described with reference to the drawings. However, it is easily understood by those skilled in the art that the embodiments can be implemented in many different modes, and that the modes and details can be variously changed without departing from the spirit and the scope thereof. .. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

In the drawings, the size, layer thickness, and area may be exaggerated for clarity. Therefore, it is not necessarily limited to that scale. It should be noted that the drawings schematically show ideal examples, and the present invention is not limited to the shapes and values shown in the drawings.

It should be noted that the ordinal numbers “first”, “second”, and “third” used in the present specification are added to avoid confusion among constituent elements and are not limited in number. ..

In this specification and the like, the terms “film” or “thin film” and “layer” can be interchanged with each other in some cases.

In the sintered body and the oxide semiconductor thin film of this specification and the like, the term “compound” and the term “crystalline phase” can be interchanged with each other in some cases.

In the present specification, the "oxide sintered body" may be simply referred to as "sintered body".
In the present specification, the “sputtering target” may be simply referred to as “target”.

[Sputtering target]
A sputtering target according to one embodiment of the present invention (hereinafter, may be simply referred to as a sputtering target according to this embodiment) includes an oxide sintered body.
The sputtering target according to the present embodiment is obtained, for example, by cutting and polishing a bulk of an oxide sintered body into a shape suitable as a sputtering target.
The sputtering target according to the present embodiment can also be obtained by bonding a sputtering target material obtained by grinding and polishing a bulk of an oxide sintered body to a backing plate.
In addition, as the sputtering target of the present embodiment according to another aspect, a target made of only an oxide sintered body is also included.

The shape of the oxide sintered body is not particularly limited.
A plate-shaped oxide sintered body as indicated by reference numeral 1 in FIG. 1 may be used.
A cylindrical oxide sintered body as indicated by reference numeral 1A in FIG. 2 may be used.
When the oxide sintered body is plate-shaped, the planar shape of the oxide sintered body may be rectangular as shown by reference numeral 1 in FIG. 1 or circular as shown by reference numeral 1B in FIG.

The oxide sintered body may be an integrally molded product, or may be divided into a plurality of pieces as shown in FIG. Each of the plurality of divided oxide sintered bodies (reference numeral 1C) may be fixed to the backing plate 3. The sputtering target obtained by bonding the plurality of oxide sintered bodies 1C to one backing plate 3 as described above may be referred to as a multi-split sputtering target. The backing plate 3 is a member for holding and cooling the oxide sintered body. The material of the backing plate 3 is not particularly limited. As the material of the backing plate 3, for example, at least one material selected from the group consisting of Cu, Ti, SUS and the like is used.

(Vickers hardness)
In the target according to the present embodiment, the average value (H _av ) of Vickers hardness on the surface of the oxide sintered body is more than 500 Hv and less than 900 Hv. In the present specification, the Vickers hardness is measured according to JIS Z 2244:2009 using a Hardness Tester (AKASHI MVK-E3). For the measurement points, data was collected every 30 mm from one end along the center line of the oxide sintered body (142 x 305 mm size), and the average value of the collected data was Vickers on the surface of the oxide sintered body. The average hardness (H _av ) is used.
When the average value (H _av ) of Vickers hardness on the surface of the oxide sintered body exceeds 500 Hv, there are few weak portions on the sputtering surface of the target. Therefore, the crack resistance of the sputtering target according to the present embodiment is improved.
If the Vickers hardness is too high, microcracks may occur during the grinding process. However, in the present embodiment, since the average value (H _av ) of the Vickers hardness of the surface of the oxide sintered body is less than 900 Hv, it is possible to suppress the generation of microcracks in the target grinding step. As a result, it is possible to suppress a decrease in crack resistance caused by microcracks.
The average value (H _av ) of Vickers hardness on the surface of the oxide sintered body is preferably 520 Hv or more and 850 Hv or less, and more preferably 600 Hv or more and 750 Hv or less.

The minimum value (H _min ) of Vickers hardness on the surface of the oxide sintered body is preferably more than 500 Hv, more preferably 600 Hv or more. When the minimum value (H _min ) of Vickers hardness exceeds 500 Hv, there are fewer weak portions on the sputtering surface of the target, and crack resistance is further improved. In addition, in this specification, the minimum value (H _min ) of Vickers hardness is the lowest value among the values of Vickers hardness measured at 10 points on the surface of the oxide sintered body. is there.

The maximum Vickers hardness (H _max ) on the surface of the oxide sintered body is preferably less than 900 Hv, and more preferably 850 Hv or less. When the minimum value (H _max ) of Vickers hardness is less than 900 Hv, generation of microcracks in the target grinding process is further suppressed, and as a result, crack resistance is further improved. In addition, in this specification, the maximum value ( _Hmax ) of Vickers hardness is the largest value among the values of the Vickers hardness of the 10 locations measured by measuring the Vickers hardness at 10 locations on the surface of the oxide sintered body. is there.

(Composition of oxide sintered body)
The oxide sintered body according to the present embodiment preferably contains indium element (In), tin element (Sn), and zinc element (Zn).
The oxide sintered body according to the present embodiment may contain a metal element other than In, Sn, and Zn within a range that does not impair the effects of the present invention, and substantially contains In, Sn, and Zn. It may be contained only or may be composed only of In, Sn and Zn. Here, “substantially” means that 95% by mass or more and 100% by mass or less (preferably 98% by mass or more and 100% by mass or less) of the metal element of the oxide sintered body is indium element (In) or tin element (Sn). ) And zinc element (Zn). The oxide sintered body according to the present embodiment may contain inevitable impurities in addition to In, Sn, Zn, and oxygen element (O) as long as the effects of the present invention are not impaired. The unavoidable impurities here mean elements that are not intentionally added and that are mixed in the raw material or the manufacturing process.

The oxide sintered body according to the present embodiment also preferably contains an indium element (In), a tin element (Sn), a zinc element (Zn), and an X element.
The oxide sintered body according to the present embodiment may contain a metal element other than In, Sn, Zn, and the X element as long as the effect of the present invention is not impaired, or substantially In, It may contain only Sn, Zn and X elements, or may consist only of In, Sn, Zn and X elements. Here, "substantially" means In, Sn, Zn and X elements in which 95% by mass or more and 100% by mass or less (preferably 98% by mass or more and 100% by mass or less) of the metal elements of the oxide sintered body are used. Means that. The oxide sintered body according to the present embodiment may contain inevitable impurities in addition to In, Sn, Zn, the X element, and the oxygen element (O) as long as the effects of the present invention are not impaired. The unavoidable impurities here mean elements that are not intentionally added and that are mixed in the raw material or the manufacturing process.
The X element is germanium element (Ge), silicon element (Si), yttrium element (Y), zirconium element (Zr), aluminum element (Al), magnesium element (Mg), ytterbium element (Yb) and gallium element (Ga). ) At least one element selected from the group consisting of

Examples of unavoidable impurities include alkali metals (Li, Na, K, Rb, etc.), alkaline earth metals (Ca, Sr, Ba, etc.), hydrogen (H) element, boron (B) element, carbon (C). It is an element, a nitrogen (N) element, a fluorine (F) element, and a chlorine (Cl) element.

The impurity concentration can be measured by ICP or SIMS.

<Measurement of impurity concentration (H, C, N, F, Si, Cl)>
The impurity concentration (H, C, N, F, Si, Cl) in the obtained sintered body was analyzed by SIMS using a sector type dynamic secondary ion mass spectrometer (IMS 7f-Auto, manufactured by AMETEK CAMECA). Can be evaluated quantitatively.
Specifically, first, using primary ions Cs ⁺ , sputtering is performed at a accelerating voltage of 14.5 kV to a depth of 20 μm from the surface of the sintered body to be measured. After that, the raster 100 μm□ (100 μm×100 μm size), the measurement area 30 μm□ (30 μm×30 μm size), and the impurities (H, C, N, F, Si, Cl) while sputtering with a primary ion for a depth of 1 μm. Integrate the mass spectrum intensity of.

Further, in order to calculate the absolute value of the impurity concentration from the mass spectrum, each impurity is injected into the sintered body by controlling the dose amount by ion implantation to prepare a standard sample having a known impurity concentration. The mass spectrum intensity of impurities (H, C, N, F, Si, Cl) is obtained from the standard sample by SIMS analysis, and the relational expression between the absolute value of the impurity concentration and the mass spectrum intensity is used as a calibration curve.
Finally, the mass spectrum intensity of the sintered body to be measured and the calibration curve are used to calculate the impurity concentration of the measured object, and this is used as the absolute value of the impurity concentration (atom·cm ⁻³ ).

<Measurement of impurity concentration (B, Na)>
The impurity concentration (B, Na) of the obtained sintered body can also be quantitatively evaluated by SIMS analysis using a sector type dynamic secondary ion mass spectrometer (IMS 7f-Auto, manufactured by AMETEK CAMECA). Measured by the same evaluation as H, C, N, F, Si, Cl except that the primary ion is O ₂ ⁺ , the accelerating voltage of the primary ion is 5.5 kV, and the mass spectrum of each impurity is measured. The absolute value (atom·cm ⁻³ ) of the target impurity concentration can be obtained.

In the oxide sintered body according to the present embodiment, it is more preferable that the atomic composition ratio of each element satisfies at least one of the following formulas (1) to (3).
0.40≦Zn/(In+Sn+Zn)≦0.80 (1)
0.15≦Sn/(Sn+Zn)≦0.40 (2)
0.10≦In/(In+Sn+Zn)≦0.35 (3)

In the formulas (1) to (3), In, Zn and Sn represent the contents of indium element, zinc element and tin element in the oxide sintered body, respectively.

When Zn/(In+Sn+Zn) is 0.40 or more, a spinel phase is easily generated in the oxide sintered body, and semiconductor characteristics can be easily obtained.
When Zn/(In+Sn+Zn) is 0.80 or less, it is possible to suppress a decrease in strength due to abnormal grain growth of the spinel phase in the oxide sintered body. When Zn/(In+Sn+Zn) is 0.80 or less, a decrease in mobility of the oxide semiconductor thin film can be suppressed.
Zn/(In+Sn+Zn) is more preferably 0.50 or more and 0.70 or less.

When Sn/(Sn+Zn) is 0.15 or more, it is possible to suppress a decrease in strength due to abnormal grain growth of the spinel phase in the oxide sintered body.
When Sn/(Sn+Zn) is 0.40 or less, aggregation of tin oxide, which causes abnormal discharge during sputtering, can be suppressed in the oxide sintered body. When Sn/(Sn+Zn) is 0.40 or less, the oxide semiconductor thin film formed by using the sputtering target can be easily etched by a weak acid such as oxalic acid. When Sn/(Sn+Zn) is 0.15 or more, it is possible to prevent the etching rate from becoming too fast, which facilitates the control of etching.
Sn/(Sn+Zn) is more preferably 0.15 or more and 0.35 or less.

If In/(In+Sn+Zn) is 0.10 or more, the bulk resistance of the obtained sputtering target can be lowered. When In/(In+Sn+Zn) is 0.10 or more, the mobility of the oxide semiconductor thin film can be prevented from being extremely low.
When In/(In+Sn+Zn) is 0.35 or less, it is possible to prevent the film from becoming a conductor during sputtering film formation, and it becomes easy to obtain characteristics as a semiconductor.
In/(In+Sn+Zn) is preferably 0.10 or more and 0.30 or less.

When the oxide sintered body according to the present embodiment contains the X element, the atomic ratio of each element preferably satisfies the following formula (1X).
0.001≦X/(In+Sn+Zn+X)≦0.05 (1X)
(In the formula (1X), In, Zn, Sn, and X represent the contents of indium element, zinc element, tin element, and X element, respectively, in the oxide sintered body.)

Within the range of the above formula (1X), the crack resistance of the oxide sintered body according to this embodiment can be sufficiently increased.
The X element is preferably at least one selected from the group consisting of silicon element (Si), aluminum element (Al), magnesium element (Mg), ytterbium element (Yb), and gallium element (Ga).
More preferably, the X element is at least one selected from the group consisting of a silicon element (Si), an aluminum element (Al) and a gallium element (Ga).
Aluminum element (Al) and gallium element (Ga) are more preferable because the composition of the oxide as a raw material is stable and the effect of improving crack resistance is high.

When X/(In+Sn+Zn+X) is 0.001 or more, the strength reduction of the sputtering target can be suppressed. When X/(In+Sn+Zn+X) is 0.05 or less, the oxide semiconductor thin film formed by using the sputtering target including the oxide sintered body can be easily etched by a weak acid such as oxalic acid. become. Furthermore, when X/(In+Sn+Zn+X) is 0.05 or less, it is possible to suppress a decrease in TFT characteristics, particularly mobility.
X/(In+Sn+Zn+X) is preferably 0.001 or more and 0.05 or less, more preferably 0.003 or more and 0.03 or less, and 0.005 or more and 0.01 or less. Is more preferable and 0.005 or more and less than 0.01 is even more preferable.
When the oxide sintered body according to the present embodiment contains the X element, the X element may be only one kind or two or more kinds. When two or more X elements are contained, X in the formula (1X) is the total atomic ratio of X elements.
The existing form of the X element in the oxide sintered body is not particularly specified. Examples of the existence form of the X element in the oxide sintered body include a form existing as an oxide, a form in which it is in solid solution, and a form segregated at grain boundaries.

The atomic ratio of each metal element of the oxide sintered body can be controlled by the blending amount of the raw materials. Further, the atomic ratio of each element can be obtained by quantitatively analyzing the contained element with an inductively coupled plasma emission spectroscopic analyzer (ICP-AES).

The oxide sintered body according to the present embodiment preferably contains a spinel structure compound represented by Zn _2-x Sn _1-y In _x+y O ₄ [0≦x<2, 0≦y<1]. .. In the present specification, a spinel structure compound may be referred to as a spinel compound. In Zn _2-x Sn _1-y In _x+y O ₄ , when x is 0 and y is 0, it is represented by Zn ₂ SnO ₄ .

The oxide sintered body according to the present embodiment preferably contains a hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m . In the present embodiment, in the formula represented by In ₂ O ₃ (ZnO) _m , m is an integer of 2 to 7, and preferably an integer of 3 to 5. When m is 2 or more, the compound has a hexagonal layered structure. When m is 7 or less, the bulk resistance of the oxide sintered body is low.

The oxide sintered body according to the present embodiment is a hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m [m=2 to 7] and Zn _2-x Sn _1-y In _x+y O ₄ [0≦ It is more preferable to contain the spinel structure compound represented by x<2,0≦y<1].

The hexagonal layered compound composed of indium oxide and zinc oxide is a compound showing an X-ray diffraction pattern belonging to the hexagonal layered compound, when measured by an X-ray diffraction method. The hexagonal layered compound contained in the oxide sintered body is a compound represented by In ₂ O ₃ (ZnO) _m .

The oxide sintered body according to the present embodiment is composed of Zn _2−x Sn _1−y In _x+y O ₄ [0≦x<2, 0≦y<1] and a spinel structure compound and In ₂ O ₃ . The represented bixbyite structure compound may be contained.

(Bulk resistance)
When the oxide sintered body according to the present embodiment contains the X element, the bulk resistance of the sputtering target can be made sufficiently low as long as the content ratio of the X element is within the range of the above formula (1X).

The bulk resistance of the sputtering target according to the present embodiment is preferably 50 mΩcm or less, more preferably 25 mΩcm or less, further preferably 10 mΩcm or less, further preferably 5 mΩcm or less, and 3 mΩcm or less. Is particularly preferable. If the bulk resistance is 50 mΩcm or less, stable film formation can be performed by DC sputtering.
The bulk resistance value can be measured based on the four-point probe method (JIS R 1637:1998) using a known resistivity meter. The number of measurement points is about 9, and it is preferable to use the average value of the measured values of 9 points as the bulk resistance value.
When the planar shape of the oxide sintered body is a quadrangle, the measurement points are preferably divided into 3×3 9 parts, and the center points of the respective quadrangles are preferably 9 points.
When the planar shape of the oxide sintered body is circular, it is preferable that the square inscribed in the circle is divided into 3×3 9 parts, and the central points of the respective squares are 9 points.

(Average grain size)
The average crystal grain size of the oxide sintered body according to the present embodiment is preferably 10 μm or less, and more preferably 8 μm or less from the viewpoint of preventing abnormal discharge and easiness of production.
When the average crystal grain size is 10 μm or less, abnormal discharge caused by grain boundaries can be prevented. The lower limit of the average crystal grain size of the oxide sintered body is not particularly limited, but is preferably 1 μm or more from the viewpoint of ease of production.
The average crystal grain size can be adjusted by selecting raw materials and changing manufacturing conditions. Specifically, it is preferable to use a raw material having a small average particle diameter, and it is more preferable to use a raw material having an average particle diameter of 1 μm or less. Further, during sintering, the higher the sintering temperature or the longer the sintering time, the larger the average crystal grain size tends to be.

The average crystal grain size can be measured as follows.
When the surface of the oxide sintered body is polished and the plane shape is a quadrangle, the surface is divided into 16 equal areas, and at the center point of each quadrangle, the magnification is 1000 times (80 μm×125 μm) in a frame. The average particle size of the particles in the frame at 16 points is determined, and finally the average value of the measured values at 16 points is taken as the average crystal grain size.
When the surface of the oxide sintered body is polished and the plane shape is circular, the square inscribed in the circle is divided into 16 equal areas, and the magnification is 1000 times (80 μm×125 μm) at 16 central points of each square. The particle size of the particles observed in the frame is measured, and the average value of the particle sizes of the particles in the 16 frames is determined.
Regarding the particle size, for particles having an aspect ratio of less than 2, the particle size of the crystal grain is measured as the equivalent circle diameter based on JIS R 1670:2006. As a procedure for measuring the circle equivalent diameter, specifically, a circle ruler is applied to the measurement target grain in the microstructure photograph, and the diameter corresponding to the area of the target grain is read. For particles having an aspect ratio of 2 or more, the average value of the longest diameter and the shortest diameter is taken as the particle diameter of the particle. The crystal grains can be observed with a scanning electron microscope (SEM). The hexagonal layered compound, the spinel compound and the bixbyite structure compound can be confirmed by the methods described in Examples below.

When the oxide sintered body according to the present embodiment contains the hexagonal layered compound and the spinel compound, the difference between the average crystal grain size of the hexagonal layered compound and the average crystal grain size of the spinel compound is 1 μm or less. Preferably. By setting the average crystal grain size within such a range, the strength of the oxide sintered body can be improved.
More preferably, the average crystal grain size of the oxide sintered body according to the present embodiment is 10 μm or less, and the difference between the average crystal grain size of the hexagonal layered compound and the average crystal grain size of the spinel compound is 1 μm or less. ..

When the oxide sintered body according to the present embodiment contains a bixbyite structure compound and a spinel compound, the difference between the average crystal grain size of the bixbite structure compound and the average crystal grain size of the spinel compound is 1 μm. The following is preferable. By setting the average crystal grain size within such a range, the strength of the oxide sintered body can be improved.
More preferably, the oxide sintered body according to the present embodiment has an average crystal grain size of 10 μm or less, and a difference between the average crystal grain size of the bixbyite structure compound and the spinel compound is 1 μm or less. ..

(Relative density)
The relative density of the oxide sintered body according to this embodiment is preferably 95% or more, and more preferably 96% or more.
When the relative density of the oxide sintered body according to the present embodiment is 95% or more, the sputtering target according to the present embodiment has high mechanical strength and excellent conductivity. Therefore, when the sputtering target according to the present embodiment is attached to the RF magnetron sputtering apparatus or the DC magnetron sputtering apparatus to perform sputtering, the stability of plasma discharge can be further enhanced. The relative density of the oxide sintered body is calculated from the inherent density of each oxide in the sintered body and the composition ratio thereof, and shows the actually measured density of the oxide sintered body with respect to the theoretical density, as a percentage. It is a thing. The relative density of the oxide sintered body is, for example, a theoretical density calculated from the inherent densities of indium oxide, zinc oxide and tin oxide, and the respective oxides of the X element contained as necessary, and their composition ratios. Is the actual measured density of the oxide sintered body with respect to the above as a percentage.

The relative density of the oxide sintered body can be measured based on the Archimedes method. The relative density (unit: %) is specifically calculated by dividing the aerial weight of the oxide sintered body by the volume (=the weight of the sintered body in water/the specific gravity of water at the measured temperature), and using the following formula (Equation 5). Based on the theoretical density ρ (g/cm ³ ).
Relative density={(air weight of oxide sintered body/volume)/theoretical density ρ}×100

ρ=(C ₁ /100/ρ ₁ +C ₂ /100/ρ ₂ ... +C _n /100/ρ _n ) ^-1 (Equation 5)
In the formula (Equation 5), C ₁ to C _n respectively represent the content (mass %) of the oxide sintered body or the constituent material of the oxide sintered body, and ρ ₁ to ρ _n are The densities (g/cm ³ ) of the constituent substances corresponding to C ₁ to C _n are shown.
Since the density is almost the same as the specific gravity, the density of each constituent substance uses the value of the specific gravity of the oxide described in the Chemical Handbook, Basic Edition, I Chemical Society of Japan, Revised 2nd Edition (Maruzen Co., Ltd.). be able to.

[Method for producing oxide sintered body]
The method for producing an oxide sintered body according to this embodiment includes a mixing/pulverizing step, a granulating step, a forming step, and a sintering step. The method for producing an oxide sintered body may include other steps. An annealing process is mentioned as another process.
Hereinafter, each step will be specifically described by taking the case of producing an ITZO-based oxide sintered body as an example.

The oxide sintered body according to the present embodiment is a mixing/pulverizing step of mixing and pulverizing an indium raw material, a zinc raw material, a tin raw material, and an X element raw material, a granulating step of granulating a raw material mixture, a molding step of molding, and a molding. It can be manufactured through a sintering step of sintering an object and an annealing step of annealing a sintered body as necessary.

(1) Mixing/Crushing Step The mixing/crushing step is a step of mixing and crushing the raw materials of the oxide sintered body to obtain a raw material mixture. The raw material mixture is preferably in powder form, for example.
In the mixing/pulverizing step, first, raw materials for the oxide sintered body are prepared.

The raw materials for producing the oxide sintered body containing In, Zn and Sn are as follows.
The indium raw material (In raw material) is not particularly limited as long as it is a compound or metal containing In.
The zinc raw material (Zn raw material) is not particularly limited as long as it is a compound or metal containing Zn.
The tin raw material (Sn raw material) is not particularly limited as long as it is a compound or metal containing Sn.

The raw materials for producing the oxide sintered body containing the element X are as follows.
The raw material of the X element is not particularly limited as long as it is a compound or a metal containing the X element.

The In raw material, the Zn raw material, the Sn raw material, and the raw material of the X element are preferably oxides.
Raw materials such as indium oxide, zinc oxide, tin oxide, and X element oxide are preferably highly pure. The purity of the raw material of the oxide sintered body is preferably 99% by mass or more, more preferably 99.9% by mass or more, and further preferably 99.99% by mass or more. When a high-purity raw material is used, a sintered body having a dense structure is obtained, and the volume resistivity of the sputtering target made of the sintered body becomes low.

The average particle size of the primary particles of the metal oxide as a raw material is preferably 0.01 μm or more and 10 μm or less, more preferably 0.05 μm or more and 5 μm or less, and 0.1 μm or more and 5 μm or less. Is more preferable.
If the average particle size of the primary particles of the metal oxide as a raw material is 0.01 μm or more, aggregation is less likely to occur, and if the average particle size is 10 μm or less, the mixing property is sufficient and a sintered body having a dense structure is obtained. Is obtained. The average particle diameter is measured by a laser diffraction type particle size distribution measuring device SALD-300V (manufactured by Shimadzu Corporation) using a median diameter D50.

The raw material of the oxide sintered body is mixed and pulverized with a bead mill, etc., by adding a dispersant for releasing the agglomeration and a thickener for adjusting the viscosity suitable for granulation with a spray dryer. Examples of the dispersant include an acrylic acid-methacrylic acid copolymer ammonia neutralized product and the like, and examples of the thickener include polyvinyl alcohol and the like.

(2) Calcining Step The raw material mixture obtained in the mixing/pulverizing step may be immediately granulated, or may be calcined before granulation. In the calcination treatment, the raw material mixture is usually baked at 700° C. or higher and 900° C. or lower for 1 hour or more and 5 hours or less.

(3) Granulation step The raw material mixture that has not been subjected to the calcination treatment or the raw material mixture that has been subjected to the calcination treatment can be subjected to the granulation treatment to improve the fluidity and filling property in the molding step of (4) below. ..
In this specification, the step of granulating the raw material of the oxide sintered body to obtain the raw material granulated powder may be referred to as a granulation step.
The granulation process can be performed using a spray dryer or the like. It is desirable that the granulated powder obtained in the granulation step has a true spherical shape in order to uniformly fill the mold in the molding step.
The granulation conditions are appropriately selected by adjusting the concentration of the raw material slurry to be introduced, the rotation speed of the spray dryer, the hot air temperature, and the like.
The slurry solution is prepared by using the slurry solution obtained in the mixing and pulverizing step as it is when using the raw material mixture which has not been subjected to the calcination treatment, and again when using the raw material mixture which has been subjected to the calcination treatment. -It is used after being prepared into a slurry solution through a grinding process.

In the method for producing an oxide sintered body according to the present embodiment, the particle size of the raw material granulated powder formed by the granulation process is controlled within the range of 25 μm or more and 150 μm or less.
When the particle size of the raw material granulated powder is 25 μm or more, the slipperiness of the raw material granulated powder with respect to the surface of the mold used in the molding step (4) below is improved, and the raw material granulated powder is sufficiently contained in the mold. Can be filled.
When the particle size of the raw material granulated powder is 150 μm or less, it is possible to prevent the particle size from being too large and the filling rate in the mold becoming low.
The grain size of the raw material granulated powder is preferably 25 μm or more and 75 μm or less.

The method for obtaining the raw material granulated powder having a particle size within a predetermined range is not particularly limited. For example, there may be mentioned a method in which the raw material mixture (raw material granulated powder) that has been subjected to the granulation treatment is sieved to select raw material granulated powder that belongs to a desired particle size range. The sieve used in this method is preferably a sieve having an opening having a size through which the raw material granulated powder having a desired particle size can pass. It is preferable to use a first sieve for selecting the raw material granulated powder based on the lower limit of the particle size range and a second sieve for selecting the raw material granulated powder based on the upper limit of the particle size range. For example, when controlling the particle size of the raw material granulated powder within the range of 25 μm or more and 150 μm or less, first, the raw material granulated powder of less than 25 μm can pass, but the size that does not pass the raw material granulated powder of 25 μm or more. The raw material granulated powder having a particle diameter of 25 μm or more is selected using the sieve (first sieve) having the opening of. Next, a raw material granulated powder having a size of 150 μm or less is allowed to pass through the raw material granulated powder after the selection, and a sieve (second sieve) having an opening size which does not pass the raw material granulated powder exceeding 150 μm is used. The raw material granulated powder within the range of 25 μm or more and 150 μm or less is selected. The order of using the second sieve first and then the first sieve may be used.
The method for controlling the particle size range of the raw material granulated powder is not limited to the method using the sieve as described above, and the raw material granulated powder to be subjected to the molding step of (4) below has a range of 25 μm or more and 150 μm or less. If

In addition, in the raw material mixture that has been subjected to the calcination treatment, particles are bonded to each other. Therefore, when performing the granulation treatment, it is preferable to perform the pulverization treatment before the granulation treatment.

(4) Molding step In the present specification, a step of filling the raw material granulated powder obtained in the granulation step in a mold and molding the raw material granulated powder filled in the mold to obtain a compact It may be called a molding step.
Examples of the molding method in the molding step include die press molding.
When a sintered compact having a high sintered density is obtained as a sputtering target, it is preformed by a die press forming or the like in the forming process, and then further consolidated by cold isostatic pressing (CIP) or the like. Preferably.

The particle size of the raw material granulated powder is preferably 25 μm or more and 150 μm or less, and more preferably 25 μm or more and 75 μm or less.
When the particle size of the raw material granulated powder is 25 μm or more and 150 μm or less, the raw material granulated powder can be sufficiently filled in the mold used in the molding step, and thus variations in the density of the molded body can be reduced.

(5) Sintering Step In this specification, the step of sintering the molded body obtained in the molding step within a predetermined temperature range may be referred to as a sintering step.
In the sintering step, a commonly used sintering method such as atmospheric pressure sintering, hot press sintering, or hot isostatic pressing (HIP; Hot Isostatic Pressing) can be used.

The sintering temperature is preferably 1310°C or higher and 1440°C or lower, and more preferably 1320°C or higher and 1430°C or lower.
When the sintering temperature is 1310° C. or higher and 1440° C. or lower, it is easy to control the average value (H _av ) of the Vickers hardness of the surface of the oxide sintered body within the above range. That is, a molded body is manufactured using the raw material granulated powder having a particle size within the predetermined range obtained in the granulation step, and the molded body is sintered at a predetermined temperature to obtain the strength of the oxide sintered body. Can be reduced, and the Vickers hardness can be prevented from becoming too large.
When the sintering temperature is 1310° C. or higher, sufficient sintering density can be obtained and the bulk resistance of the sputtering target can be lowered.
When the sintering temperature is 1440° C. or lower, the sublimation of zinc oxide during sintering can be suppressed.

In the sintering step, the rate of temperature increase from room temperature to the sintering temperature is preferably 0.1° C./minute or more and 3° C./minute or less.
In addition, in the process of raising the temperature, the temperature may be maintained at 700° C. or higher and 800° C. or lower for 1 hour or more and 10 hours or less, and may be kept at the predetermined temperature for the predetermined time, and then raised to the sintering temperature.

The sintering time varies depending on the sintering temperature, but is preferably 1 hour or more and 50 hours or less, more preferably 2 hours or more and 30 hours or less, and is 3 hours or more and 20 hours or less. More preferable.
Examples of the atmosphere during sintering include an atmosphere of air or oxygen gas, an atmosphere containing air or oxygen gas and a reducing gas, or an atmosphere containing air or oxygen gas and an inert gas. Examples of the reducing gas include hydrogen gas, methane gas, carbon monoxide gas and the like. Examples of the inert gas include argon gas and nitrogen gas.

(6) Annealing Step In the method for manufacturing an oxide sintered body according to this embodiment, the annealing step is not essential. When carrying out the annealing step, the temperature is usually maintained at 700° C. or higher and 1100° C. or lower for 1 hour or more and 5 hours or less.
In the annealing step, the sintered body may be cooled once and then again heated and annealed, or may be annealed when the temperature is lowered from the sintering temperature.
Examples of the atmosphere during annealing include an atmosphere of air or oxygen gas, an atmosphere containing air or oxygen gas and a reducing gas, or an atmosphere containing air or oxygen gas and an inert gas. Examples of the reducing gas include hydrogen gas, methane gas, carbon monoxide gas and the like. Examples of the inert gas include argon gas and nitrogen gas.

Also, when producing an oxide sintered body of a system different from the ITZO system, it can be produced by the same process as described above.

[Method of manufacturing sputtering target]
A sputtering target can be manufactured by cutting the oxide sintered body obtained by the above-described manufacturing method into an appropriate shape and polishing the surface of the oxide sintered body as necessary.
Specifically, a sputtering target material (sometimes referred to as a target material) is obtained by cutting the oxide sintered body into a shape suitable for mounting on a sputtering device. A sputtering target is obtained by adhering this target material to a backing plate.

When the oxide sintered body is used as the target material, the surface roughness Ra of the sintered body is preferably 0.5 μm or less. Examples of the method of adjusting the surface roughness Ra of the sintered body include a method of grinding the sintered body with a surface grinder.

The surface of the sputtering target material is preferably finished with a #100 to 1,000 diamond grindstone, and particularly preferably with a 400 to 800 diamond grindstone. By using a diamond grindstone of 100 or more, or 1,000 or less, cracking of the sputtering target material can be prevented.
The surface roughness Ra of the sputtering target material is preferably 0.5 μm or less, and it is preferable that the sputtering target material has a non-directional grinding surface. If the surface roughness Ra of the sputtering target material is 0.5 μm or less and a polishing surface having no directionality is provided, abnormal discharge and generation of particles can be prevented.

Finally, the obtained sputtering target material is cleaned. Examples of the cleaning treatment method include any method such as air blowing and washing with running water. When removing foreign matter by air blow, foreign matter can be removed more effectively by sucking air with a dust collector from the side opposite to the nozzle of air blow.
In addition to the above-mentioned cleaning treatment by air blowing or washing with running water, ultrasonic cleaning or the like may be further performed. As the ultrasonic cleaning, a method of performing multiple oscillation at a frequency of 25 kHz or more and 300 kHz or less is effective. For example, it is preferable to use a method in which 12 kinds of frequencies are multiplexed and oscillated in steps of 25 kHz in a frequency range of 25 kHz to 300 kHz for ultrasonic cleaning.

The thickness of the sputtering target material is usually 2 mm or more and 20 mm or less, preferably 3 mm or more and 12 mm or less, more preferably 4 mm or more and 9 mm or less, and further preferably 4 mm or more and 6 mm or less. preferable.

A sputtering target can be manufactured by bonding the sputtering target material obtained through the above steps and treatments to a backing plate. Alternatively, a plurality of sputtering target materials may be attached to one backing plate to produce substantially one sputtering target (multi-splitting target).

The sputtering target according to the present embodiment includes an oxide sintered body, and the average value (H _av ) of the Vickers hardness of the surface of the oxide sintered body is more than 500 Hv and less than 900 Hv, so that crack resistance is high. It is an improved sputtering target.

By forming a film by sputtering using the sputtering target according to the present embodiment, crack resistance is improved, so that an oxide semiconductor thin film can be stably manufactured.

The present invention will be specifically described below based on examples. The invention is not limited to the examples.

A sputtering target made of an ITZO-based oxide sintered body was prepared.

(Example 1)
First, the following powders were weighed so that the atomic ratio (In: 25 atomic %, Sn: 15 atomic %, Zn: 60 atomic %) was used as a raw material.
In raw material: Indium oxide powder having a purity of 99.99 mass% (average particle diameter: 0.3 μm)
-Sn raw material: tin oxide powder with a purity of 99.99 mass% (average particle size: 1.0 μm)
-Zn raw material: Zinc oxide powder having a purity of 99.99 mass% (average particle diameter: 3.0 μm)

A median diameter D50 was adopted as the average particle diameter of the oxide powder used as a raw material, and the average particle diameter was measured with a laser diffraction particle size distribution analyzer SALD-300V (manufactured by Shimadzu Corporation).

Next, an acrylic acid/methacrylic acid copolymer ammonia neutralized product (manufactured by Sanmei Kasei Co., Ltd., Banster X754B) as a dispersant, polyvinyl alcohol as a thickening agent, and water were added to these raw materials, and the mixture was mixed with a bead mill 2 The mixture was pulverized for a period of time to obtain a granulation slurry solution having a solid content concentration of 70% by mass. The resulting slurry solution was supplied to a spray dryer and granulated under the conditions of a rotation speed of 12,000 and a hot air temperature of 150°C to obtain a raw material granulated powder.
The raw material granulated powder is removed by passing the raw material granulated powder through a 200 mesh sieve to remove the granulated powder having a particle size of more than 75 μm, and then passing through the 500 mesh sieve to remove the granulated powder under 25 μm. The particle size was adjusted to be in the range of 25 μm or more and 75 μm or less.
FIG. 5 shows an SEM observation image of the raw material granulated powder prepared in Example 1.

Next, this raw material granulated powder was uniformly filled in a mold having an inner diameter of 300 mm×600 mm×9 mm, and pressure-molded by a cold press machine. After the pressure molding, it was molded at a pressure of 294 MPa with a cold isotropic pressure device (CIP device) to obtain a molded body.
The three compacts thus obtained were heated to 780° C. in an oxygen atmosphere in a sintering furnace, held at 780° C. for 5 hours, further heated to 1325° C., and the sintering temperature (1325 C.) for 20 hours and then furnace cooled to obtain an oxide sintered body. The heating rate was 2° C./min.
The obtained three oxide sintered bodies were respectively cut and surface-ground to obtain three oxide sintered body plates of 142 mm×305 mm×5 mmt. Of these, one was used for characteristic evaluation and two were used for a G1 target [142 mm×610 mm (two divisions)×5 mmt].
In the surface grinding, a surface grinding machine is used to first grind an oxide sintered body plate with a #100 diamond grindstone, and then with a fine grindstone #200→#400→#800. processed.
When the oxide sintered body plate after the grinding process was observed with an optical microscope, microcracks and the like were not particularly observed.

Using one of the three obtained oxide sintered body plates, first, the Vickers hardness was measured, and then appropriately cut into a predetermined size, and various measurements were performed.

(1) Measurement of Vickers hardness The Vickers hardness was measured by using Hardness Tester (AKASHI MVK-E3) according to JIS Z 2244:2009. The measurement points were obtained by collecting 10 points of data every 30 mm from one end on the central line of the oxide sintered body (size 142×305 mm) and evaluating the average value.

(2) Confirmation of crystal structure The oxide sintered body plate on which Vickers hardness had been measured was cut out for X-ray diffraction measurement, and the crystal structure was examined under the following conditions using an X-ray diffraction measurement device (XRD). As a result, in the oxide sintered body according to Example 1, a hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m (where m=an integer of 2 to 7) and Zn _2-x. It was confirmed that a spinel compound represented by Sn _1-y In _x+y O ₄ [0≦x<2, 0≦y<1] was present. FIG. 6 shows an XRD chart of the oxide sintered body according to Example 1.
・Device: Smartlab manufactured by Rigaku Corporation
・X-ray: Cu-Kα ray (wavelength 1.5418×10 ^-10 m)
・Parallel beam, 2θ-θ reflection method, continuous scan (2.0°/min)
・Sampling interval: 0.02°
・Diffusion slit (Divence Slit, DS): 1.0mm
-Scattering slit (SS): 1.0 mm
・Receiving slit (RS): 1.0 mm

(3) Confirmation of composition Similarly, using the remainder of the oxide sintered body plate, the atomic ratio of the oxide sintered body was analyzed by an inductively coupled plasma emission spectroscopy analyzer (ICP-AES, manufactured by Shimadzu Corporation). The results are as follows.
Zn/(In+Sn+Zn)=0.60
Sn/(Sn+Zn)=0.20
In/(In+Sn+Zn)=0.25

(Examples 2 to 5)
The oxide sintered bodies according to Examples 2 to 5 were manufactured in the same manner as in Example 1 except that the sintering temperature in Example 1 was changed to the sintering temperature shown in Table 1.

(Comparative Examples 1 and 2)
The oxide sintered bodies according to Comparative Examples 1 and 2 were manufactured in the same manner as in Example 1 except that the sintering temperature in Example 1 was changed to the sintering temperature shown in Table 1.
When the oxide sintered body according to Comparative Example 2 was observed with an optical microscope after grinding, microcracks were confirmed.

(Comparative Examples 3 to 4)
The oxide sintered bodies according to Comparative Examples 3 to 4 were molded by a mold without granulating the raw material in Example 1, and the sintering temperatures were set to the sintering temperatures shown in Table 1, respectively. It was produced in the same manner as in Example 1 except that it was changed.

(Comparative Examples 5-6)
The oxide sintered bodies according to Comparative Examples 5 to 6 were manufactured in the same manner as in Example 1 except that the sintering temperature in Example 1 was changed to the sintering temperature shown in Table 1.

(Manufacture of sputtering target)
Next, by using two oxide sintered body plates according to Examples 1 to 5 and Comparative Examples 1 to 6 and bonding them to a backing plate, G1 size: 142 mm×610 mm (two divisions)×5 mmt sputtering The target was manufactured.

The bonding rate was 98% or more for all targets. When the oxide sintered body was bonded to the backing plate, cracks did not occur in the oxide sintered body, and the sputtering target could be manufactured well. The bonding rate (bonding rate) was confirmed by X-ray CT.

(Crack resistance during sputtering)
Using the prepared sputtering target, pre-sputtering was performed for 1 hour in a G1 sputtering device under the conditions that the atmosphere gas was 100% Ar and the sputtering power was 1 kW. Here, the G1 sputtering device refers to a first-generation mass-production sputtering device having a substrate size of about 300 mm×400 mm. After pre-sputtering, the power was changed under the film forming conditions shown in Table 2 to continuously discharge for 2 hours, after the discharge was completed, the chamber was opened, the presence of cracks was visually confirmed, the power was increased, and the discharge test was repeated. Then, the crack resistance was evaluated.
Crack resistance is the maximum sputter power that does not crack the sputtering target. Regarding crack resistance, a case of 1.80 kW or more was regarded as acceptable. Table 1 shows the evaluation results of crack resistance of each sputtering target.

It was found that the sputtering targets using the oxide sintered bodies according to Examples 1 to 5 have excellent crack resistance. It is considered that the surface of the oxide sintered body had a high Vickers hardness.
The sputtering targets using the oxide sintered bodies according to Comparative Examples 1, 3 and 4 did not generate microcracks during grinding and polishing, but the crack resistance during sputtering was inferior to that of Examples 1 to 5. I understood. It is considered that this is due to the low Vickers hardness of the surface of the oxide sintered bodies according to Comparative Examples 1, 3 and 4.
The sputtering target using the oxide sintered body according to Comparative Example 5 did not generate microcracks during grinding and polishing, but it was found that the crack resistance during sputtering was inferior to that of Examples 1 to 5. It is considered that this is due to the low Vickers hardness of the surface of the oxide sintered body according to Comparative Example 5.
Regarding the oxide sintered body according to Comparative Example 6, when the oxide sintered body after grinding was observed with an optical microscope, microcracks were confirmed.

1, 1A, 1B, 1C... oxide sintered body, 3... backing plate.

Claims

An oxide sintered body,
The average value of the Vickers hardness of the surface of the oxide sintered body is more than 500 Hv and less than 900 Hv.
Oxide sintered body.
A sputtering target containing the oxide sintered body according to claim 1.
The oxide sintered body contains an indium element, a tin element and a zinc element,
The sputtering target according to claim 2.
The oxide sintered body further contains an X element,
The X element is at least one element selected from the group consisting of germanium element, silicon element, yttrium element, zirconium element, aluminum element, magnesium element, ytterbium element and gallium element,
The sputtering target according to claim 3.
The oxide sintered body satisfies the atomic composition ratio range represented by the following formulas (1), (2) and (3):
The sputtering target according to claim 3 or 4.
0.40≦Zn/(In+Sn+Zn)≦0.80 (1)
0.15≦Sn/(Sn+Zn)≦0.40 (2)
0.10≦In/(In+Sn+Zn)≦0.35 (3)
The oxide sintered body is a hexagonal layered compound represented by In 2 O 3 (ZnO)m [m=2 to 7] and Zn 2-x Sn 1-y In x+y O 4 [0≦x<2. Including a spinel structure compound represented by 0≦y<1],
The sputtering target according to any one of claims 2 to 5.
It is a manufacturing method of the sputtering target for manufacturing the sputtering target according to any one of claims 2 to 6,
A step of granulating the raw material of the oxide sintered body to obtain a raw material granulated powder having a particle size of 25 μm or more and 150 μm or less;
A step of filling the raw material granulated powder in a mold and molding the raw material granulated powder filled in the mold to obtain a molded body;
Sintering the molded body at 1310° C. or higher and 1440° C. or lower,
Manufacturing method of sputtering target.
The method for manufacturing a sputtering target according to claim 7,
The particle size of the raw material granulated powder is 25 μm or more and 75 μm or less,
Manufacturing method of sputtering target.