CN113677821A - Oxide sintered body, sputtering target, and method for producing sputtering target - Google Patents
Oxide sintered body, sputtering target, and method for producing sputtering target Download PDFInfo
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- CN113677821A CN113677821A CN202080013820.8A CN202080013820A CN113677821A CN 113677821 A CN113677821 A CN 113677821A CN 202080013820 A CN202080013820 A CN 202080013820A CN 113677821 A CN113677821 A CN 113677821A
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- sintered body
- oxide sintered
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- sputtering target
- grinding wheel
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- 238000005477 sputtering target Methods 0.000 title claims description 101
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- 150000001875 compounds Chemical class 0.000 claims description 41
- 239000006061 abrasive grain Substances 0.000 claims description 33
- 238000000034 method Methods 0.000 claims description 33
- 229910052738 indium Inorganic materials 0.000 claims description 26
- 229910052718 tin Inorganic materials 0.000 claims description 24
- 229910052725 zinc Inorganic materials 0.000 claims description 23
- 239000000203 mixture Substances 0.000 claims description 21
- 239000011029 spinel Substances 0.000 claims description 18
- 229910052596 spinel Inorganic materials 0.000 claims description 18
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 claims description 13
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 claims description 12
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 11
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 10
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- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 4
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- 229910003107 Zn2SnO4 Inorganic materials 0.000 description 1
- 229910007604 Zn—Sn—O Inorganic materials 0.000 description 1
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Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/453—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B7/00—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor
- B24B7/20—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground
- B24B7/22—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor characterised by a special design with respect to properties of the material of non-metallic articles to be ground for grinding inorganic material, e.g. stone, ceramics, porcelain
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/34—Sputtering
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/34—Sputtering
- C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
Abstract
The present invention relates to an oxide sintered body, the surface roughness Rz of the surface of which is less than 2.0 [ mu ] m.
Description
Technical Field
The present invention relates to an oxide sintered body, a sputtering target, and a method for producing a sputtering target.
Background
Conventionally, in a display device such as a liquid crystal display or an organic EL display which is driven by a thin film transistor (hereinafter, referred to as a "TFT"), an amorphous silicon film or a crystalline silicon film is mainly used as a channel layer of the TFT.
On the other hand, in recent years, with the demand for higher definition of displays, oxide semiconductors have attracted attention as materials used in channel layers of TFTs.
Among oxide semiconductors, an amorphous oxide semiconductor (In-Ga-Zn-O, hereinafter abbreviated as "IGZO") composed of indium, gallium, zinc, and oxygen is particularly preferably used because of its high carrier mobility. However, IGZO has a disadvantage that the use of In and Ga as raw materials increases the raw material cost.
From the viewpoint of reducing the raw material cost, Zn-Sn-O (hereinafter abbreviated as "ZTO") and In-Sn-Zn-O (hereinafter abbreviated as "ITZO") containing Sn In place of Ga In IGZO have been proposed.
ITZO shows a very high mobility as compared with IGZO, and therefore is expected as a next-generation oxide semiconductor material that is advantageous for miniaturization of TFTs and narrowing of a panel frame.
However, ITZO has a large thermal expansion coefficient and a low thermal conductivity, and therefore has a technical problem that cracks are likely to occur due to thermal stress when it is bonded to a Cu or Ti back sheet or when it is sputtered.
In recent studies, it has been reported that reliability, which is the largest technical problem of oxide semiconductor materials, can be improved by densifying a film.
In order to densify the film, high-power film formation is effective. However, in a large-scale mass production apparatus, breakage of the end portion of the target where plasma is concentrated becomes a problem, and particularly, the target of the ITZO-based material tends to be easily broken.
For example, patent document 1 describes that in an oxide sintered body substantially composed of indium, tin, magnesium, and oxygen, a high flexural strength can be achieved by appropriately adjusting the composition of the sintered body and the sintering conditions. Further, patent document 1 describes that stable sputtering can be performed by making the oxide sintered body have a high flexural strength and thus causing less generation of fine particles during sputtering.
Documents of the prior art
Patent document
Patent document 1: international publication No. 2017/158928
Disclosure of Invention
Technical problem to be solved by the invention
Examples of the cause of the crack in the sputtering target include various causes such as density variation, particle size variation, pores, and microcracks.
The cause of the crack may be a grinding streak generated in a step of grinding the sputtering target in a plane. When sputtering is performed using a sputtering target having a ground streak, arc discharge occurs, or cracks are likely to occur due to tensile stress on the surface caused by thermal shrinkage of the target after sputtering discharge.
On the other hand, it is known that the depth of cut of the abrasive grains is reduced by reducing the particle size of the abrasive grains embedded in the grinding wheel, thereby reducing grinding streaks generated in the grinding process of the sputtering target.
For example, patent document 1 describes that an oxide sintered body composed of indium, tin, magnesium, and oxygen is polished with a #80 grinding wheel and then polished with a #400 grinding wheel, thereby obtaining a sintered body having a surface roughness Ra of 0.46 μm.
However, as described in patent document 1, even when the surface of the oxide sintered body is polished with the #80 grinding wheel and then polished with the #400 grinding wheel, the sputtering target including the oxide sintered body may have insufficient crack resistance.
The invention aims to provide an oxide sintered body and a sputtering target with improved crack resistance, and a method for manufacturing the sputtering target.
Solution for solving the above technical problem
[1A] An oxide sintered body, comprising a sintered body of an oxide,
the surface roughness Rz of the surface of the oxide sintered body is less than 2.0 [ mu ] m.
[2A] A sputtering target comprising the oxide sintered body described in [1A ].
[1] A sputtering target comprising an oxide sintered body,
the surface roughness Rz of the surface of the oxide sintered body is less than 2.0 [ mu ] m.
[2] The sputtering target as recited in [1] or [2A ],
the oxide sintered body contains an indium element, a tin element, and a zinc element.
[3] The sputtering target according to [2],
the oxide sintered body further contains an element X,
the X element is at least 1 or more element selected from the group consisting of germanium element, silicon element, yttrium element, zirconium element, aluminum element, magnesium element, ytterbium element, and gallium element.
[4] The sputtering target as recited in [2] or [3],
the oxide sintered body satisfies the range of atomic composition ratios 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] The sputtering target according to any one of [2] to [4],
the oxide sintered body contains In2O3(ZnO)m[m＝2～7]Hexagonal layered compound represented by the formula and Zn2SnO4A spinel structure compound represented.
[5A] The sputtering target according to any one of [2] to [4],
the oxide sintered body contains In2O3(ZnO)m[m＝2～7]Hexagonal layered compound represented by the formula and Zn2-xSn1-yInx+yO4[0≤x<2，0≤y<1]A spinel structure compound represented.
[6A] The sputtering target according to any one of [2] to [5], [2A ] and [5A ], wherein a ratio H/L of a depth (H) to a width (L) of a grinding mark having a largest depth and a smallest width among the grinding marks of the oxide sintered body is less than 0.2.
[6] A method for producing a sputtering target according to any one of [1] to [5], [2A ], [5A ] and [6A ].
[7] The method for producing a sputtering target according to [6],
comprising a step of grinding the surface of the oxide sintered body,
the abrasive grain size of the 1 st grinding wheel used for the first grinding is 100 μm or less.
[8] The method for producing a sputtering target according to [7],
further grinding the surface of the oxide sintered body using a 2 nd grinding wheel having a smaller abrasive grain diameter than the abrasive grain diameter of the 1 st grinding wheel after grinding with the 1 st grinding wheel,
after grinding with the 2 nd grinding wheel, the surface of the oxide sintered body is further ground with a 3 rd grinding wheel having a smaller abrasive grain diameter than that of the 2 nd grinding wheel.
[9] The method of manufacturing a sputtering target according to [7] or [8], wherein a feed speed V (m/min) of a grinding object, a grinding wheel peripheral speed V (m/min) of the 1 st grinding wheel, a depth of cut t (μm), and an abrasive grain diameter d (μm) of the 1 st grinding wheel satisfy the following relational expression (4).
(v/V)1/3×(t)1/6×d＜50…(4)
According to an aspect of the present invention, an oxide sintered body and a sputtering target having improved crack resistance can be provided. Further, according to an aspect of the present invention, a method for manufacturing the sputtering target can be provided.
Drawings
Fig. 1 is a perspective view showing the shape of a target according to an embodiment of the present invention.
Fig. 2 is a perspective view showing the shape of a target according to an embodiment of the present invention.
Fig. 3 is a perspective view showing the shape of a target according to an embodiment of the present invention.
Fig. 4 is a perspective view showing the shape of a target according to an embodiment of the present invention.
Fig. 5 is a plan view of the oxide sintered body (after surface grinding) according to example 1, which was observed with a confocal laser scanning microscope.
Fig. 6 is a plan view of the oxide sintered body (after surface grinding) according to example 2, which was observed with a confocal laser scanning microscope.
Fig. 7 is a plan view of the oxide sintered body (after surface grinding) according to example 3, which was observed with a confocal laser scanning microscope.
Fig. 8 is a plan view of the oxide sintered body (after surface grinding) according to example 4, which was observed with a confocal laser scanning microscope.
Fig. 9 is a plan view of the oxide sintered body (after surface grinding) according to example 5, which was observed with a confocal laser scanning microscope.
Fig. 10 is a plan view of the oxide sintered body (after surface grinding) according to example 6, which was observed with a confocal laser scanning microscope.
Fig. 11 is a plan view of the oxide sintered body (after surface grinding) according to comparative example 1, which was observed with a confocal laser scanning microscope.
Fig. 12 is a plan view of the oxide sintered body (after surface grinding) according to comparative example 2, which was observed with a confocal laser scanning microscope.
Fig. 13 is a 3D observation image of the oxide sintered body (after surface grinding) according to example 1, which was obtained by a confocal laser scanning microscope.
Fig. 14 is a 3D observation image of the oxide sintered body (after surface grinding) according to example 2, which was obtained by a confocal laser scanning microscope.
Fig. 15 is a 3D observation image of the oxide sintered body (after surface grinding) according to example 3, which was obtained by a confocal laser scanning microscope.
Fig. 16 is a 3D observation image of the oxide sintered body (after surface grinding) according to example 4, which was obtained by a confocal laser scanning microscope.
Fig. 17 is a 3D observation image of the oxide sintered body (after surface grinding) according to example 5, which was obtained by a confocal laser scanning microscope.
Fig. 18 is a 3D observation image of the oxide sintered body (after surface grinding) according to example 6 by a confocal laser scanning microscope.
Fig. 19 is a 3D observation image of the oxide sintered body (after surface grinding) according to comparative example 1, which was obtained by a confocal laser scanning microscope.
Fig. 20 is a 3D observation image of the oxide sintered body (after surface grinding) according to comparative example 2, which was obtained by a confocal laser scanning microscope.
Fig. 21 is an XRD spectrum of the oxide sintered body according to example 1.
Fig. 22 is a graph showing the relationship between the surface roughness Rz and the crack resistance.
Fig. 23 is a plan view of the oxide sintered body (after surface grinding) according to comparative example 3, which was observed with a confocal laser scanning microscope.
Fig. 24 is a 3D observation image of the oxide sintered body (after surface grinding) according to comparative example 3, which was obtained by a confocal laser scanning microscope.
Fig. 25 is a view showing a cross-sectional profile of a surface roughness measurement position of the oxide sintered body according to example 1 after the surface grinding.
Fig. 26 is a view showing a cross-sectional profile of a surface roughness measurement position of the oxide sintered body according to example 2 after the surface grinding.
Fig. 27 is a view showing a cross-sectional profile of a surface roughness measurement position of the oxide sintered body according to example 3 after the surface grinding.
Fig. 28 is a view showing a cross-sectional profile of a surface roughness measurement position of the oxide sintered body according to example 4 after the surface grinding.
Fig. 29 is a view showing a cross-sectional profile of a surface roughness measurement position of the oxide sintered body according to example 5 after the surface grinding.
Fig. 30 is a view showing a cross-sectional profile of a surface roughness measurement position of the oxide sintered body according to example 6 after the surface grinding.
Fig. 31 is a view showing a cross-sectional profile of a surface roughness measurement position of the oxide sintered body according to comparative example 1 after the surface grinding.
Fig. 32 is a view showing a cross-sectional profile of a surface roughness measurement position of the oxide sintered body according to comparative example 2 after the surface grinding.
Fig. 33 is a view showing a cross-sectional profile of a surface roughness measurement position of the oxide sintered body according to comparative example 3 after the surface grinding.
Detailed Description
Hereinafter, embodiments will be described with reference to the drawings and the like. However, the embodiments may be implemented in many different ways, and it will be readily understood by those skilled in the art that various modifications of the embodiments and details may be made without departing from the spirit and scope thereof. Therefore, the present invention is not limited to the contents described in the following embodiments.
In the drawings, the size, the thickness of layers, the regions, and the like may be exaggerated for clarity. Therefore, the present invention is not limited to the size, layer thickness, region, and the like shown in the drawings. The drawings schematically show an ideal example, and the present invention is not limited to the shapes, values, and the like shown in the drawings.
The ordinal numbers such as "1 st", "2 nd", and "3 rd" used in the present specification are added to avoid confusion of the constituent elements, and the constituent elements not described as being limited in number are not limited in number.
In the present specification and the like, terms such as "film" or "thin film" and terms such as "layer" may be substituted for each other as the case may be.
In the sintered body and the oxide semiconductor thin film in this specification and the like, a term of "compound" and a term of "crystal phase" may be replaced with each other in some cases.
In this specification, the "oxide sintered body" may be simply referred to as "sintered body".
In this specification, a "sputtering target" is sometimes simply referred to as a "target".
[ sputtering target ]
The cracks of the sputtering target occur from the weak portion of the target.
Therefore, the present inventors considered reducing the variation in strength in the sputtering target plane, particularly improving the minimum strength, as a measure for improving the crack resistance.
Conventionally, the grinding streaks in a sputtering target have been evaluated by the surface roughness Ra (sometimes referred to as arithmetic mean roughness), and it is considered that the flexural strength, which is one of the indexes showing the strength of the target, is sufficient in patent document 1. As described above, it has been conventionally considered that Ra is sufficient for evaluating the grinding streaks on the surface of the oxide sintered body, and the difference between the surface roughness Ra and the surface roughness Rz (sometimes referred to as the maximum height) is small.
However, as a result of detailed examination of the grinding damage of ITZO, the present inventors found that ITZO is brittle as compared with conventional target materials, and generally found a portion (hole) where a large crystal structure is separated in lumps in addition to grinding streaks observed on the surface of the oxide sintered body after surface grinding. It is found that the depth of the peeled portion is 1 digit or more deeper than the depth of the normal grinding streak.
The inventors of the present invention have conducted intensive studies on a grinding method, and as a result, have found the following findings: in order to reduce the peeled portion as described above, as a grinding wheel for grinding, grinding is started from a grinding wheel having an intermediate abrasive grain size, and grinding is performed by gradually changing to a grinding wheel having a small abrasive grain size, whereby the peeled portion can be reduced without leaving a large hole (that is, the surface roughness Rz can be reduced), and as a result, the crack resistance of the sputtering target is greatly improved.
The present inventors invented the present invention based on these findings.
A sputtering target according to an embodiment of the present invention (hereinafter, may be simply referred to as a sputtering target of the present embodiment) includes an oxide sintered body.
The sputtering target according to the present embodiment can be obtained by, for example, cutting and grinding the oxide sintered body into a shape suitable for a sputtering target.
The sputtering target according to the present embodiment can also be obtained by bonding a sputtering target material obtained by cutting and grinding a block of an oxide sintered body to a backing plate.
In addition, as the sputtering target of the present embodiment in another aspect, a target composed of only an oxide sintered body may be exemplified.
The shape of the oxide sintered body is not particularly specified.
The oxide sintered body may be a plate-like oxide sintered body as shown by reference numeral 1 in fig. 1.
The oxide sintered body may be a cylindrical oxide sintered body as shown by reference numeral 1A in fig. 2.
In the case where the oxide sintered body has a plate shape, the planar shape of the oxide sintered body may be a rectangle as shown by reference numeral 1 in fig. 1, or may be a circle as shown by reference numeral 1B in fig. 3.
The oxide sintered body may be an integrally molded product, or may be divided into a plurality of pieces as shown in fig. 4. The oxide sintered bodies (reference numeral 1C) divided into a plurality of parts may be fixed to the back plate 3. A sputtering target obtained by bonding the plurality of oxide sintered bodies 1C to the 1 backing plate 3 in this manner is sometimes referred to as a multi-divided sputtering target. The back plate 3 is a member for holding and cooling the oxide sintered body. The material of the back plate 3 is not particularly limited. As the material of the back plate 3, for example, at least one material selected from the group consisting of Cu, Ti, SUS, and the like can be used.
(surface roughness Rz)
In the target according to the present embodiment, the surface roughness Rz (maximum height) of the oxide sintered body is less than 2.0 μm. In the present specification, the surface roughness Rz is measured based on a cross-sectional profile when observed at an objective magnification of × 100 (about 2000 times) using a confocal Laser Scanning Microscope (LSM) (manufactured by Lasertec corporation, "opterlics H1200"), in accordance with JIS B0601: 2001 and JIS B0610: 2001, respectively. The measurement site of the surface roughness Rz was set to 4cm by cutting out the center part of the oxide sintered body plate after grinding2(2 cm. times.2 cm) of the surface of the test piece for measurement.
If the surface roughness Rz of the oxide sintered body is less than 2.0 μm, the crack resistance of the sputtering target is improved. The reason why the crack resistance is improved in this manner is considered to be that the crystal structure is not largely exfoliated and the surface smoothness of the oxide sintered body is high.
The surface roughness Rz of the oxide sintered body is preferably 1.5 μm or less, more preferably 1.0 μm or less.
The oxide sintered body in the sputtering target has a bonding surface to be bonded to the backing plate, and a sputtering surface to be sputtered, which is a surface opposite to the bonding surface. In the present embodiment, the surface roughness Rz of the surface corresponding to the sputtering surface may be less than 2.0 μm. The smaller the surface roughness Rz of the bonding surface is, the more preferable, but if it is too small, the wettability of indium (In) as a wax agent at the bonding process is poor, and the bonding rate is lowered, so that it can be selected appropriately under the condition that the wettability can be secured.
In the target, the thermal stress generated on the sputtering surface after the sputtering discharge is tensile stress. Although the thermal stress generated on the sputtering surface may cause the generation of cracks, a compressive stress opposite to the thermal stress is generated on the bonding surface of the rear surface of the target, so that cracks are less likely to be generated and the influence of the thermal stress generated on the sputtering surface is small.
(surface roughness Ra)
In the target according to the present embodiment, the surface roughness Ra (arithmetic mean roughness) of the oxide sintered body is preferably less than 0.5 μm, and more preferably 0.25 μm or less.
If the surface roughness Ra is less than 0.5. mu.m, arc discharge or the like is less likely to occur during sputtering, and the discharge stability is excellent. That is, when a new target is used in a normal process, pre-sputtering is performed at low power in order to improve the surface roughness. When the surface roughness Ra is small, the time for the pre-sputtering can be shortened, and the sputtering discharge at high power can be shifted to in a short time.
(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 other metal elements than In, Sn, and Zn, may substantially contain only In, Sn, and Zn, or may be composed of only In, Sn, and Zn, within a range not impairing the effects of the present invention. Here, "substantially" means that 95% by mass to 100% by mass (preferably 98% by mass to 100% by mass) of the metal elements of the oxide sintered body are indium element (In), tin element (Sn), and zinc element (Zn). The oxide sintered body of the present embodiment may contain inevitable impurities other than In, Sn, Zn, and the oxygen element (0) within a range not impairing the effects of the present invention. The inevitable impurities referred to herein are elements that are not intentionally added but are mixed in the raw materials or the production 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 other metal elements than In, Sn, Zn, and X elements, may substantially contain only In, Sn, Zn, and X elements, or may be composed of only In, Sn, Zn, and X elements, within a range not to impair the effects of the present invention. Here, "substantially" means that 95% by mass to 100% by mass (preferably 98% by mass to 100% by mass) of the metal elements of the oxide sintered body are In, Sn, Zn, and X elements. The oxide sintered body according to the present embodiment may contain inevitable impurities other than In, Sn, Zn, X, and oxygen (O) within a range not impairing the effects of the present invention. The inevitable impurities referred to herein are elements that are not intentionally added but are mixed in the raw materials or the production process.
The X element is at least 1 or more selected from the group consisting of 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).
Examples of the inevitable impurities include alkali metals (such as Li, Na, K, and Rb), alkaline earth metals (such as Ca, Sr, and Ba), hydrogen (H), boron (B), carbon (C), nitrogen (N), fluorine (F), and chlorine (Cl).
The impurity concentration can be measured by ICP or SIMS.
< measurement of impurity concentration (H, C, N, F, Si, Cl) >
The impurity concentrations (H, C, N, F, Si, Cl) in the obtained sintered body were quantitatively evaluated by SIMS analysis using a fan-shaped dynamic secondary ion mass spectrometer (IMS7F-Auto, manufactured by Armitksameka (AMETEK CAMECA)).
Specifically, the primary ion Cs is used first+Sputtering was performed at an acceleration voltage of 14.5kV from the surface of the sintered body to be measured to a depth of 20 μm. Then, the primary ions are used to form a grating of 100 μm2(size 100. mu. m.times.100. mu.m), measurement area 30 μm2The mass spectrum intensity of impurities (H, C, N, F, Si, Cl) was integrated while sputtering was performed in an amount of (size 30. mu. m.times.30 μm) and depth 1 μm.
Further, in order to calculate the absolute value of the impurity concentration from the mass spectrum, each impurity was implanted into the sintered body by controlling the dose by ion implantation, and a standard sample having a known impurity concentration was prepared. The mass spectrum intensity of impurities (H, C, N, F, Si, Cl) was obtained by SIMS analysis of the standard sample, and the relation between the absolute value of the impurity concentration and the mass spectrum intensity was used as a calibration curve.
Finally, the impurity concentration of the measurement object is calculated using the mass spectrum intensity of the sintered body of the measurement object and the calibration curve, and is taken as the absolute value (atom · cm) of the impurity concentration-3)。
< measurement of impurity concentration (B, Na) >
The impurity concentration (B, Na) in the obtained sintered body can also be quantitatively evaluated by SIMS analysis using a fan-shaped dynamic secondary ion mass spectrometer (IMS7f-Auto, manufactured by Armitksameka (AMETEK CAMECA)). Except that the primary ion is O2 +The absolute value (atom · cm) of the impurity concentration of the measurement object can be obtained by the same evaluation as the measurement of H, C, N, F, Si, and Cl except that the mass spectrum of each impurity is measured at an acceleration voltage of the primary ion of 5.5kV-3)。
In the oxide sintered body according to the present embodiment, the atomic composition ratio of each element more preferably satisfies at least one of 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)
In the formulas (1) to (3), In, Zn, and Sn represent the contents of the indium element, the zinc element, and the tin element In the oxide sintered body, respectively.
If Zn/(In + Sn + Zn) is 0.40 or more, a spinel phase is easily formed In the oxide sintered body, and semiconductor characteristics can be easily obtained.
If Zn/(In + Sn + Zn) is 0.80 or less, the decrease In strength due to abnormal grain growth of the spinel phase In the oxide sintered body can be suppressed. Further, if 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 to 0.70.
If Sn/(Sn + Zn) is 0.15 or more, a decrease in strength due to abnormal grain growth of the spinel phase in the oxide sintered body can be suppressed.
If Sn/(Sn + Zn) is 0.40 or less, the aggregation of tin oxide, which causes abnormal discharge during sputtering, in the oxide sintered body can be suppressed. In addition, if Sn/(Sn + Zn) is 0.40 or less, the oxide semiconductor thin film formed using the sputtering target can be easily etched with a weak acid such as oxalic acid. If Sn/(Sn + Zn) is 0.15 or more, the etching rate can be suppressed from becoming too high, and the control of etching becomes easy.
Sn/(Sn + Zn) is more preferably 0.15 to 0.35.
If In/(In + Sn + Zn) is 0.10 or more, the bulk resistance of the obtained sputtering target can be reduced. In addition, if In/(In + Sn + Zn) is 0.10 or more, the mobility of the oxide semiconductor thin film can be suppressed from extremely decreasing.
If In/(In + Sn + Zn) is 0.35 or less, the film can be prevented from becoming a conductor during sputtering film formation, and characteristics as a semiconductor can be easily obtained.
In/(In + Sn + Zn) is more preferably 0.10 to 0.30.
When the oxide sintered body according to the present embodiment contains an element X, 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 In the oxide sintered body, respectively.)
If the amount is within the range of the formula (1X), the crack resistance of the oxide sintered body according to the present embodiment can be sufficiently improved.
The X element is preferably at least one selected from the group consisting of silicon (Si), aluminum (Al), magnesium (Mg), ytterbium (Yb), and gallium (Ga).
The X element is more preferably at least one selected from the group consisting of silicon element (Si), aluminum element (Al), and gallium element (Ga).
The composition of the oxide containing aluminum (Al) and gallium (Ga) as the raw material is stable, and the effect of improving the crack resistance is high, and therefore, this is more preferable.
When X/(In + Sn + Zn + X) is 0.001 or more, the strength of the sputtering target can be suppressed from being lowered. When X/(In + Sn + Zn + X) is 0.05 or less, the oxide semiconductor thin film formed by using the sputtering target comprising the oxide sintered body can be easily etched by using a weak acid such as oxalic acid. Further, if X/(In + Sn + Zn + X) is 0.05 or less, the TFT characteristics, particularly the mobility, can be suppressed from being lowered.
X/(In + Sn + Zn + X) is preferably 0.001 to 0.05, more preferably 0.003 to 0.03, even more preferably 0.005 to 0.01, and even more preferably 0.005 to less than 0.01.
When the oxide sintered body according to the present embodiment contains X element, the X element may be only 1 kind, or 2 or more kinds. When 2 or more X elements are contained, X in the formula (1X) is the total of the atomic ratios of the X elements.
The presence of the element X in the oxide sintered body is not particularly limited. Examples of the mode of existence of the element X in the oxide sintered body include a mode of existence as an oxide, a mode of solid solution, and a mode of segregation 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. The atomic ratio of each element can be determined by quantitative analysis of the contained elements by an inductively coupled plasma emission spectrometer (ICP-AES).
The oxide sintered body according to the present embodiment preferably contains Zn2-xSn1-yInx+yO4[0≤x<2，0≤y<1]A spinel structure compound represented. In this specification, the spinel-structured compound is sometimes referred to as a spinel compound. Zn2-xSn1-yInx+yO4In the case where x is 0 and y is 0, Zn is used2SnO4And (4) showing.
The oxide sintered body according to the present embodiment preferably contains In2O3(ZnO)mThe hexagonal layered compound is shown. In this embodiment, In2O3(ZnO)mIn the formula, m is an integer of 2 to 7, preferably an integer of 3 to 5. When m is 2 or more, the compound has a hexagonal layered structure. If m is 7 or less, the volume resistivity of the oxide sintered body becomes low.
The oxide sintered body according to the present embodiment more preferably contains In2O3(ZnO)m[m＝2～7]Hexagonal layered compound represented by the formula and Zn2-xSn1-yInx+yO4[0≤x＜2，0≤y＜1]A spinel structure compound represented.
The hexagonal layered compound composed of indium oxide and zinc oxide is a compound showing an X-ray diffraction pattern attributed to the hexagonal layered compound in X-ray diffraction measurement. The hexagonal layered compound contained In the oxide sintered body is In2O3(ZnO)mThe compound shown in the specification.
The oxide sintered body according to the present embodiment may contain Zn2-xSn1-yInx+yO4[0≤x＜2，0≤y＜1]A spinel structure compound represented by the formula and In2O3The compound with a bixbyite structure is shown.
(body resistance)
When the oxide sintered body according to the present embodiment contains the X element, if the content ratio of the X element is within the range of the formula (1X), the bulk resistance of the sputtering target can be sufficiently reduced.
The sputtering target according to the present embodiment has a bulk resistance of preferably 50m Ω cm or less, more preferably 25m Ω cm or less, still more preferably 10m Ω cm or less, yet more preferably 5m Ω cm or less, and particularly preferably 3m Ω cm or less. If the volume resistance is 50m Ω cm or less, the film can be stably formed by direct current sputtering.
The bulk resistance value can be measured using a known resistivity meter based on a four-probe method (JISR 1637: 1998). Preferably, the measurement site is about 9 points, and the average value of the values at 9 points measured is used as the bulk resistance value.
When the planar shape of the oxide sintered body is a quadrangle, the plane is preferably divided into 9 parts by 3 × 3, and the center point of 9 of each quadrangle is preferably used as a measurement site.
When the planar shape of the oxide sintered body is a circle, it is preferable that a square inscribed in the circle is divided into 9 parts by 3 × 3, and the center point at 9 points of each square is set as a measurement site.
(average crystal particle diameter)
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 facilitating production.
If 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, and is preferably 1 μm or more from the viewpoint of easy production.
The average crystal particle size can be adjusted by selecting raw materials and changing production conditions. Specifically, it is preferable to use a raw material having a small average particle size, and more preferable to use a raw material having an average particle size of 1 μm or less. Further, in the 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 particle diameter can be measured as follows.
When the planar shape of the surface of the sintered oxide body was a quadrangle, the surface was divided into 16 parts in an equal area, the particle diameters observed in a frame having a magnification of 1000 times (80 μm × 125 μm) were measured at the 16-point center point of each quadrangle, the average values of the particle diameters of the particles in the 16-point frame were obtained, and finally the average value of the 16-point measurement values was defined as the average crystal particle diameter.
When the surface of the oxide sintered body was ground and the planar shape was circular, a square inscribed in a circle was equally divided into 16 parts, and at the 16-point center point of each square, the particle diameters of particles observed in a frame having a magnification of 1000 times (80 μm × 125 μm) were measured to obtain the average value of the particle diameters of particles in the 16-point frame.
For particles with an aspect ratio of less than 2, the particle size is determined in accordance with JIS R1670: the grain size is measured as a circle-equivalent diameter 2006. Specifically, as a step of measuring the equivalent circle diameter, a circle ruler is attached to the measurement target particle of the microstructure photograph, and the diameter corresponding to the area of the target particle is read. The average value of the longest diameter and the shortest diameter of particles having an aspect ratio of 2 or more is defined as the particle diameter of the particles. The crystal grains can be observed by 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 the examples described later.
When the oxide sintered body according to the present embodiment contains a hexagonal layered compound and a 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 preferably 1 μm or less. By setting the average crystal grain size in 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 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.
In addition, when the oxide sintered body according to the present embodiment includes a bixbyite structure compound and a spinel compound, the difference between the average crystal grain size of the bixbyite structure compound and the average crystal grain size of the spinel compound is preferably 1 μm or less. By setting the average crystal grain size in 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 particle size of 10 μm or less, and the difference between the average crystal particle size of the bixbyite structure compound and the average crystal particle size of the spinel compound is 1 μm or less.
(relative Density)
The relative density of the oxide sintered body according to the present 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 electrical conductivity. Therefore, the stability of plasma discharge can be further improved when the sputtering target according to the present embodiment is mounted on an RF magnetron sputtering apparatus or a DC magnetron sputtering apparatus and sputtering is performed. The relative density of the oxide sintered body is calculated from the respective intrinsic densities of the oxides in the sintered body and their composition ratios, and the actually measured density of the oxide sintered body with respect to the theoretical density is expressed in percentage. The relative density of the oxide sintered body is calculated from the intrinsic density of each of indium oxide, zinc oxide, tin oxide, and an oxide of an X element contained as needed, and the composition ratio thereof, for example, and the actually measured density of the oxide sintered body with respect to the theoretical density is expressed as a percentage.
The relative density of the oxide sintered body can be measured based on the archimedes method. In particular, the method of manufacturing a semiconductor device,the weight in air of the oxide sintered body was divided by the volume (weight in water of the sintered body/specific gravity of water at the measurement temperature), and the relative theoretical density ρ (g/cm) based on the following formula (number 5) was determined3) The value of (c) is defined as the relative density (unit: %).
Relative density { (weight/volume in air of oxide sintered body)/theoretical density ρ } × 100
ρ＝(C1/100/ρ1+C2/100/ρ2…+Cn/100/ρn)-1… (number 5)
In addition, in the formula (number 5), C1～CnRepresents the content (% by mass) of the oxide sintered body or the constituent substance of the oxide sintered body, respectively, (% by mass) (. rho)1～ρnIs represented by the formula1～CnDensity (g/cm) of each corresponding constituent substance3)。
Since the density and the specific gravity are almost equal, the density of each constituent material can be a value of the specific gravity of the oxide described in "basic note for chemical overview I" revised 2 edition of japan chemical society (pill corp.).
(ratio H/L of depth (H) to width (L) of grinding mark of surface roughness)
In the present invention, "grinding marks" refer to marks caused in a grinding step in the production of a sputtering target from an oxide sintered body.
In the oxide sintered body according to the present embodiment, the ratio H/L of the depth (H) to the width (L) of the grinding mark having the largest depth and the smallest width is preferably less than 0.2, and more preferably 0.19 or less.
In the oxide sintered body according to the present embodiment, if the ratio H/L of the depth (H) to the width (L) of the grinding mark is less than 0.2, the grinding mark is gentle, and the grinding mark is prevented from becoming a starting point of fracture, thereby preventing the tensile strength of the oxide sintered body from increasing.
In the oxide sintered body according to the present embodiment, the ratio H/L of the depth (H) to the width (L) of the grinding mark is preferably 0.01 or more, and more preferably 0.05 or more.
By taking a grinding mark countermeasure such as reducing the feed rate of the grinding target portion and reducing the depth of cut of the grinding wheel, the depth of the grinding mark and the difference between the grinding mark and the background can be reduced.
If the ratio H/L of the depth (H) to the width (L) of the grinding mark of the oxide sintered body according to the present embodiment is 0.01 or more, the above-described measures against the grinding mark can be taken, and a sputtering target can be efficiently produced on a production line.
[ method for producing oxide sintered body ]
The method for producing an oxide sintered body according to the present embodiment includes a mixing and pulverizing step, a granulating step, a forming step, and a sintering step. The method for producing the oxide sintered body may include other steps. The other step may be an annealing step.
Hereinafter, each step will be specifically described by taking a case of producing an ITZO-based oxide sintered body as an example.
The oxide sintered body of the present embodiment can be produced through a mixing and 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 the raw material mixture, a molding step of molding the raw material mixture, a sintering step of sintering the molded body, and an annealing step of annealing the sintered body as necessary.
(1) Mixing and pulverizing process
The mixing and pulverizing step is a step of mixing and pulverizing raw materials of the oxide sintered body to obtain a raw material mixture. The raw material mixture is preferably in a powder form, for example.
In the mixing and pulverizing step, first, a raw material of the oxide sintered body is 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 containing In or a metal.
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 containing Sn or a metal.
The raw materials for producing the oxide sintered body containing the X element 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 material, the Zn material, the Sn material, and the X element material are preferably oxides.
The raw materials such as indium oxide, zinc oxide, tin oxide, and X element oxide are preferably high-purity raw materials. The purity of the raw material of the oxide sintered body is preferably 99 mass% or more, more preferably 99.9 mass% or more, and further preferably 99.99 mass% or more. When a high-purity raw material is used, a sintered body having a dense structure can be obtained, and the volume resistivity of a sputtering target composed of the sintered body is lowered.
The average particle diameter of 1 st order particles of the metal oxide as the 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 further preferably 0.1 μm or more and 5 μm or less.
If the average particle diameter of 1 st order particles of the metal oxide as a raw material is 0.01 μm or more, aggregation becomes difficult, and if the average particle diameter is 10 μm or less, mixing becomes sufficient and a sintered body of a dense structure can be obtained. The average particle diameter was defined as median diameter D50. The average particle diameter (median diameter D50) was measured by a laser diffraction particle size distribution measuring apparatus SALD-300V (manufactured by Shimadzu corporation).
A dispersant for dissolving aggregation and a thickener for adjusting the viscosity suitable for granulation in a spray dryer are added to the raw material of the oxide sintered body, and the mixture is mixed and pulverized by a bead mill or the like. The dispersant may, for example, be an acrylic/methacrylic acid copolymer neutralized with ammonia, and the thickener may, for example, be polyvinyl alcohol.
(2) Calcination treatment Process
The raw material mixture obtained by the mixing and pulverizing steps may be granulated immediately or subjected to a calcination treatment before the granulation. The calcination treatment is usually carried out by firing the raw material mixture at 700 ℃ to 900 ℃ for 1 hour to 5 hours.
(3) Granulation step
The raw material mixture not subjected to the calcination treatment or the raw material mixture subjected to the calcination treatment can be improved in fluidity and filling property in the molding step (4) described below by the granulation treatment.
In this specification, a step of granulating a raw material of an oxide sintered body to obtain a raw material granulated powder is sometimes referred to as a granulation step.
The granulation treatment can be performed using a spray dryer or the like. The shape of the granulated powder obtained in the granulating step is not particularly limited, but is preferably a regular sphere shape in order to fill the mold uniformly in the molding step.
The granulation conditions may be appropriately selected by adjusting the concentration of the introduced raw material slurry, the rotation speed of the spray dryer, the temperature of hot air, and the like.
The slurry solution was prepared as follows: when a raw material mixture that has not been subjected to calcination treatment is used, the slurry solution obtained in the mixing and pulverizing step is used as it is, and when a raw material mixture that has been subjected to calcination treatment is used, the slurry solution is prepared by passing through the mixing and pulverizing step again and then used.
In the method for producing an oxide sintered body according to the present embodiment, the particle diameter of the raw material granulated powder formed by the granulation treatment is not particularly limited, but is preferably controlled within a range of 25 μm to 150 μm.
When the particle diameter of the raw material granulated powder is 25 μm or more, the sliding property of the raw material granulated powder with respect to the surface of the mold used in the molding step (4) described below is improved, and the raw material granulated powder can be sufficiently filled in the mold.
If the particle diameter of the raw material granulated powder is 150 μm or less, it is possible to suppress the filling ratio in the mold from being lowered due to an excessively large particle diameter.
The particle size of the raw material granulated powder is more preferably 25 μm to 75 μm.
The method for obtaining the raw material granulated powder having a particle diameter within the predetermined range is not particularly limited. For example, a method of sieving a raw material mixture (raw material granulated powder) subjected to granulation treatment to screen a raw material granulated powder belonging to a desired particle size range may be mentioned. The sieve used in this method is preferably a sieve having openings of a size that allows the raw granulated powder of a desired particle size to pass through. It is preferable to use a 1 st sieve for screening the raw material granulated powder with reference to the lower limit value of the particle size range and a 2 nd sieve for screening the raw material granulated powder with reference to the upper limit value of the particle size range. For example, when the particle size of the raw material granulated powder is controlled to be in the range of 25 μm to 150 μm, first, the raw material granulated powder having a particle size of 25 μm or more is screened using a sieve (1 st sieve) having openings with a size through which the raw material granulated powder smaller than 25 μm can pass but the raw material granulated powder of 25 μm or more cannot pass. Next, the raw granulated powder after screening was screened for a raw granulated powder in the range of 25 μm to 150 μm using a sieve (No. 2 sieve) having openings with a size through which the raw granulated powder of 150 μm or less can pass but the raw granulated powder of more than 150 μm cannot pass. Or a sequence of using the 2 nd sieve first and then using the 1 st sieve.
The method of 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 used in the molding step (4) described below may be controlled to a desired range.
In addition, in the raw material mixture subjected to the calcination treatment, since the particles are bonded to each other, in the case of performing the granulation treatment, it is preferable to perform the pulverization treatment before the granulation treatment.
(4) Shaping step
In this specification, the following process may be referred to as a molding process: and a step of filling the raw material granulated powder obtained in the granulation step into a mold, and molding the raw material granulated powder filled in the mold to obtain a molded body.
The molding method in the molding step may, for example, be die press molding.
When a sintered body having a high sintered density is obtained as the sputtering target, it is preferable that the sputtering target is preliminarily formed by press forming with a die or the like in a forming step, and then is further consolidated by Cold Isostatic Pressing (CIP) forming or the like.
(5) Sintering step
In this specification, the following process may be referred to as a sintering process: and a step of sintering the molded body obtained in the molding step in a predetermined temperature range.
In the sintering step, a sintering method generally performed, such as atmospheric pressure sintering, Hot press sintering, or Hot Isostatic Pressing (HIP) sintering, can be used.
The sintering temperature is not particularly limited, but is preferably 1310 ℃ to 1440 ℃, and more preferably 1320 ℃ to 1430 ℃.
When the sintering temperature is 1310 ℃ or higher, a sufficient sintering density can be obtained and the bulk resistance of the sputtering target can be reduced.
When the sintering temperature is 1440 ℃ or lower, sublimation of zinc oxide during sintering can be suppressed.
In the sintering step, the rate of temperature rise from room temperature to the sintering temperature is not particularly limited, but is preferably 0.1 ℃/min to 3 ℃/min.
In the step of raising the temperature, the temperature may be maintained at 700 ℃ to 800 ℃ for 1 hour to 10 hours, and after the temperature is maintained at a predetermined temperature for a predetermined time, the temperature may be raised again to the sintering temperature.
The sintering time varies depending on the sintering temperature, and is preferably 1 hour to 50 hours, more preferably 2 hours to 30 hours, and further preferably 3 hours to 20 hours.
The atmosphere during sintering may, for example, be an atmosphere of air or oxygen, an atmosphere containing air or oxygen and a reducing gas, or an atmosphere containing air or oxygen and an inert gas. Examples of the reducing gas include hydrogen gas, methane gas, and carbon monoxide gas. Examples of the inert gas include argon and nitrogen.
(6) Annealing step
In the method for producing an oxide sintered body according to the present embodiment, the annealing step is not an essential step. When the annealing step is performed, the temperature is usually maintained at 700 ℃ to 1100 ℃ for 1 hour to 5 hours.
The annealing step may be performed by once cooling the sintered body and then raising the temperature again, or may be performed when the temperature is lowered from the sintering temperature.
The atmosphere during annealing may, for example, be an atmosphere of air or oxygen, an atmosphere containing air or oxygen and a reducing gas, or an atmosphere containing air or oxygen and an inert gas. Examples of the reducing gas include hydrogen gas, methane gas, and carbon monoxide gas. Examples of the inert gas include argon and nitrogen.
In addition, when an oxide sintered body having a system different from that of ITZO is manufactured, the oxide sintered body can be manufactured by the same steps as described above.
[ method for producing sputtering target ]
The sputtering target according to the present embodiment can be produced by cutting the oxide sintered body obtained by the above-described production method into an appropriate shape and grinding the surface of the oxide sintered body.
Specifically, the oxide sintered body is cut into a shape suitable for mounting in a sputtering apparatus, thereby obtaining a sputtering target material (also referred to as a target material). The target raw material is bonded to a backing plate, whereby a sputtering target can be obtained.
The surface roughness Rz of the oxide sintered body according to the present embodiment used as a target material is less than 2.0 μm, preferably 1.5 μm or less, and more preferably 1.0 μm or less.
As a method for adjusting the surface roughness Rz of the oxide sintered body, for example, a method of grinding the surface using a grinding wheel having a predetermined number of meshes or more can be mentioned.
(7) Surface grinding process
In this specification, the following process may be referred to as a surface grinding process: and grinding the surface of the oxide sintered body used as the target material.
The method for manufacturing a sputtering target according to the present embodiment includes a surface grinding step.
The abrasive grain diameter of the grinding wheel (1 st grinding wheel) for grinding the surface of the oxide sintered body first is preferably 100 μm or less, more preferably 80 μm or less. The grain size of the abrasive grains is a value obtained by converting the mesh number of the grinding wheel into a grain size mark.
If the grain size of the abrasive grains of the 1 st grindstone is 100 μm or less, the crystal structure is hard to be largely exfoliated. On the other hand, when the abrasive grain diameter of the 1 st grindstone is 100 μm or less, the grinding time may be increased, but by adjusting the feed speed V (m/min) of the object to be ground, the peripheral speed V (m/min) of the 1 st grindstone, the depth of cut t (μm), and the abrasive grain diameter d (μm) of the 1 st grindstone to the range in which the relational expression (4) holds, the grinding time can be prevented from being increased, and improvement of crack resistance and manufacturing efficiency of the sputtering target can be achieved at the same time.
(v/V)1/3×(t)1/6×d＜50…(4)
The feed speed V (m/min) of the object to be ground, the circumferential speed V (m/min) of the 1 st grinding wheel, the depth of cut t (μm), and the abrasive grain diameter d (μm) of the 1 st grinding wheel preferably satisfy the following relational expression (4A), and more preferably satisfy the following relational expression (4B).
(v/V)1/3×(t)1/6×d＜30…(4A)
(v/V)1/3×(t)1/6×d＜20…(4B)
The grinding conditions for the 2 nd and 3 rd grinders and the like used for the 2 nd and subsequent grinding preferably satisfy the above relational expression (4), more preferably satisfy the above relational expression (4A), and still more preferably satisfy the above relational expression (4B).
In this specification, the mesh size of the grinding wheel is sometimes referred to as grain size.
In the surface grinding step of the present embodiment, a 1 st grindstone having abrasive grains of 100 μm or less in particle size is preferably used. When a grinding wheel having a grain size of 100 μm or less is used as the 1 st grinding wheel, the crystal structure can be prevented from largely peeling off in lump. Even if the portion (hole) having a large crystal structure and being exfoliated is ground for a long time by using a smaller-mesh grinding wheel, the exfoliated peripheral portion becomes brittle, the hole cannot be removed, and the crack resistance is not improved.
In the surface grinding step according to the present embodiment, it is preferable to grind the surface of the oxide sintered body using grinding wheels having a plurality of meshes. In this case, it is preferable to perform grinding using a grinding wheel having a smaller abrasive grain diameter than that of the 1 st grinding wheel in addition to the grinding by the 1 st grinding wheel.
For example, the following modes can be exemplified: after grinding with the 1 st grinding wheel, the surface of the oxide sintered body is further ground using a grinding wheel (2 nd grinding wheel) having an abrasive grain size smaller than that of the 1 st grinding wheel, and after grinding with the 2 nd grinding wheel, the surface of the oxide sintered body is further ground using a grinding wheel (3 rd grinding wheel) having an abrasive grain size smaller than that of the 2 nd grinding wheel. In the surface grinding step according to the present embodiment, it is also preferable to perform 3 or more stages of grinding as in this embodiment.
When grinding is performed in a plurality of stages, the following combinations (P1) to (P4) can be mentioned as combinations of abrasive grain diameters of the grinding wheel used in each stage.
<3, grinding processing:
>
(P1)
<4, grinding:
>
(P2)
<5, grinding:
>
(P3)
<6, grinding:
>
(P4)
the abrasive grain diameter of the grinding wheel used in the surface grinding step of the present embodiment is preferably 100 μm or less. If the abrasive grain diameter of the grinding wheel is 100 μm or less, cracking of the sputtering target material can be prevented.
The grinding wheel used in the surface grinding step of the present embodiment is preferably a diamond grinding wheel.
The surface roughness Ra of the oxide sintered body after the surface grinding step according to the present embodiment is preferably 0.5 μm or less.
Preferably, the sputtering target material has a surface roughness Ra of 0.5 μm or less and has a polished surface without directionality. If the sputtering target material has a surface roughness Ra of 0.5 μm or less and a grinding surface having no directionality, it is possible to prevent abnormal discharge and generation of fine particles.
As a method for adjusting the surface roughness Ra of the sintered body, for example, a method of grinding the sintered body by a surface grinder can be exemplified.
Finally, the obtained sputtering target raw material is subjected to cleaning treatment. The cleaning treatment may be performed by any method, for example, air blowing or running water washing. When the foreign matter is removed by the air blow, the foreign matter can be more effectively removed by sucking air from the opposite side of the nozzle through which the air blow is made by the dust collector.
In addition to the above cleaning treatment by air blowing or running water cleaning, ultrasonic cleaning or the like may be further performed. As the ultrasonic cleaning, a method of performing multiple oscillation in a frequency range of 25kHz to 300kHz is effective. For example, a method of performing ultrasonic cleaning by performing multiple oscillations at 12 frequencies at 25kHz intervals in a frequency range of 25kHz to 300kHz is preferable.
The thickness of the sputtering target material is usually 2mm to 20mm, preferably 3mm to 12mm, more preferably 4mm to 9mm, and particularly preferably 4mm to 6 mm.
The sputtering target can be produced by bonding the sputtering target material obtained through the above-described steps and treatments to the backing plate. Further, a plurality of sputtering target materials may be attached to 1 backing plate to substantially manufacture 1 sputtering target (multi-divided sputtering target).
The oxide sintered body as a sputtering target material has a bonding surface to be bonded to the backing plate and a sputtering surface to be sputtered, which is a surface on the opposite side of the bonding surface. In the present embodiment, it is preferable that the surface having a surface roughness Rz of less than 2.0 μm is a sputtering surface, and the surface opposite to the sputtering surface is a bonding surface. Therefore, in the method for manufacturing a sputtering target according to the present embodiment, the bonding surface side of the oxide sintered body is bonded to the backing plate.
The sputtering target according to the present embodiment includes an oxide sintered body, and the surface roughness Rz of the surface of the oxide sintered body is less than 2.0 μm, and therefore the crack resistance is improved.
When sputtering deposition is performed using the sputtering target according to the present embodiment, the crack resistance is improved, and therefore, an oxide semiconductor thin film can be stably produced.
Examples
The present invention is specifically described below based on examples. The present invention is not limited to the examples.
(production of sputtering target)
A sputtering target composed of an ITZO-based oxide sintered body was produced.
(example 1)
First, the following powders were weighed out In terms of atomic ratio (In: 25 atomic%, Sn: 15 atomic%, Zn: 60 atomic%) as raw materials.
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 having a purity of 99.99 mass% (average particle diameter: 1.0 μm)
Raw material of Zn: zinc oxide powder having a purity of 99.99 mass% (average particle diameter: 3 μm)
The average particle diameter of the oxide powder used as a raw material was D50 as a median diameter. The average particle diameter (median diameter D50) was measured by a laser diffraction particle size distribution measuring apparatus SALD-300V (manufactured by Shimadzu corporation).
Subsequently, to these raw materials, an acrylic methacrylic acid copolymer ammonia-neutralized product (BANGSTER X754B, manufactured by samming chemical corporation) as a dispersant, polyvinyl alcohol as a thickener, and water were added, and mixed and pulverized for 2 hours by a bead mill to obtain a slurry solution for granulation having a solid content concentration of 70 mass%. The obtained slurry solution was supplied to a spray dryer, and granulated at a rotation speed of 12,000 revolutions and a hot air temperature of 150 ℃ to obtain a raw material granulated powder.
The granulated powder of the raw material is passed through a 200-mesh sieve to remove the granulated powder having a particle size of more than 75 μm, and then passed through a 500-mesh sieve to remove the granulated powder having a particle size of less than 25 μm, thereby adjusting the particle size of the granulated powder of the raw material to a range of 25 μm to 75 μm.
Then, the raw granulated powder was uniformly filled in a mold having an inner diameter of 300mm × 600mm × 9mm, and press-molded by a cold press. After the press molding, the molded article was molded under a pressure of 294MPa using a Cold Isostatic Press (CIP) apparatus to obtain a molded article.
The 3 molded bodies thus obtained were heated to 780 ℃ in an oxygen atmosphere using a sintering furnace, then held at 780 ℃ for 5 hours, further heated to 1400 ℃ and held at the sintering temperature (1400 ℃) for 20 hours, and then cooled in the furnace to obtain an oxide sintered body. The temperature was raised at a rate of 2 ℃ per minute.
The obtained 3 sintered oxide plates were cut and ground to obtain 3 plates of a sintered oxide plate having a thickness of 142mm × 305mm × 5 mmt. 1 of these blocks was used for characteristic evaluation, and the other 2 blocks were used for G1 target [142 mm. times.610 mm (2 equal parts). times.5 mmt ].
The surface grinding was carried out by using a surface grinder and a diamond grinding wheel having a grinding wheel grain size of 80 μm to grind the oxide sintered body. The surface grinding conditions were as follows.
Plane grinding conditions:
feed speed v of the grinding object: 1m/min
Grinding wheel peripheral speed V: 500m/min
Grinding wheel cutting depth (cutting depth t): 5 μm
Abrasive grain diameter d of grinding wheel: 80 μm
The type of the grinding wheel is as follows: diamond grinding wheel
After grinding under the above-mentioned surface grinding conditions, grinding was carried out in this order under the above-mentioned surface grinding conditions using a diamond grinding wheel having a grinding wheel abrasive grain size of 40 μm, followed by a diamond grinding wheel having a grinding wheel abrasive grain size of 20 μm, and a grinding wheel having a fine abrasive grain size.
(production of target)
The obtained 2 sintered oxide plates (142mm × 305mm × 5mmt) were bonded to a Cu backing plate to produce a G1 target. Bonding is performed by using the surface after the plane grinding as a sputtering surface and the surface opposite to the sputtering surface (the surface roughly polished with a grinding wheel having a grain size of 130 μm) as a bonding surface, and bonding the bonding surface side of the oxide sintered body plate to the back plate. The bonding rate was 98% or more in all the targets. When the oxide sintered body plate is bonded to the backing plate, no cracks are generated in the oxide sintered body plate, and a sputtering target is favorably produced. The adhesion rate (bonding rate) was confirmed by X-ray CT.
(examples 2 to 6)
Except that the grinding conditions in example 1 were changed to the conditions shown in table 1, the oxide sintered bodies according to examples 2 to 6 were produced in the same manner as in example 1.
Sputtering targets according to examples 2 to 6 were produced in the same manner as in example 1 using the oxide sintered plate according to examples 2 to 6.
Comparative examples 1 to 2
Except that the grinding conditions and the abrasive grain size of the grinding wheel in example 1 were changed to those shown in table 1, the oxide sintered bodies according to comparative examples 1 to 2 were produced in the same manner as in example 1.
Comparative example 3
An oxide sintered body according to comparative example 3 was produced in the same manner as in example 1, except that the grinding conditions and the abrasive grain size of the grinding wheel in example 1 were changed to those shown in table 1.
Sputtering targets according to comparative examples 1 to 3 were produced in the same manner as in example 1 using the oxide sintered plate according to comparative examples 1 to 3.
Further, the following characteristics were measured for the obtained oxide sintered body and sputtering target. The measurement results are shown in table 1.
(1) Surface roughness Rz
The surface roughness Rz of the surface of the oxide sintered body was evaluated based on a cross-sectional profile observed with a confocal Laser Scanning Microscope (LSM) (manufactured by Lasertec corporation, "optellics H1200") at an objective magnification of × 100 (about 2000 times) from the central portion of 1 oxide sintered body plate (142mm × 305mm × 5mmt) subjected to grinding processing other than the target production. The data of the surface roughness Rz are calculated by software attached to a confocal laser scanning microscope. Data calculation was according to JIS B0601: 2001 and JIS B0610: 2001. the surface roughness Rz can be evaluated by using a sample cut out from the central portion of the oxide sintered body plate.
The oxide sintered bodies according to the examples and comparative examples were observed and measured with the observation position being the center portion and the measurement direction being the direction perpendicular to the vertical direction by corresponding the grinding direction to the vertical direction of the grinding streak.
(2) Ratio of depth (H) to width (L) of grinding mark in oxide sintered body
In the cross-sectional profile data calculated for the surface roughness, the minimum height of the surface unevenness identified as the oxide sintered body was set to 30% of the surface roughness Rz. In the recognized asperities, a grinding mark is defined between the convex apexes adjacent to each other. The convex apex of the concavity and convexity is defined as a point where the slope of the tangent to the concavity and convexity (the angle formed by the tangent drawn in the curve of the concavity and convexity profile and the flat surface of the substrate) is 0 degree.
Herein, grinding marks corresponding to the surface roughness Rz having the maximum depth (H) are determined, and the ratio of the depth (H) to the width (L) is calculated for the grinding marks having the minimum width (L) in the surface longitudinal direction.
Fig. 5 to 12 and 23 show the planar observation images of the oxide sintered bodies of examples 1 to 6 and comparative examples 1 to 3 after the planar grinding. In addition, the dotted lines in the images of fig. 5 to 12 and 23 indicate the positions where the surface roughness is measured. Further, fig. 25 to 33 show cross-sectional profiles of the surface roughness measurement positions of the oxide sintered bodies according to examples 1 to 6 and comparative examples 1 to 3 after the surface grinding. The thick box in the cross-sectional profile shows the measurement range of the depth (H) and the width (L) of the grinding mark for calculating the ratio H/L. The start point, end point, and measurement result in the surface roughness measurement are shown in table 2.
Fig. 13 to 20 and 24 show 3D observation images of the oxide sintered bodies according to examples 1 to 6 and comparative examples 1 to 3 after the surface grinding.
(3) XRD measurement
The crystal structure was investigated by an X-ray diffraction measuring apparatus (XRD) using the oxide sintered body plate used for surface roughness measurement. As a result, it was confirmed that In was present In the oxide sintered bodies according to examples 1 to 6 and comparative examples 1 to 32O3(ZnO)m(wherein m is an integer of 2 to 7) and Zn2-xSn1-yInx+yO4[0≤x＜2，0≤y＜1]The spinel compound shown. Fig. 21 shows an XRD spectrum of the oxide sintered body according to example 1.
An apparatus: smartlab manufactured by Kyowa Co Ltd
X-ray: Cu-K alpha ray (wavelength 1.5418X 10)-10m)
Parallel beam, 2 theta-theta reflection method, continuous scan (2.0 deg./min)
Sampling interval: 0.02 degree
Divergent Slit (DS): 1.0mm
Scattering Slit (SS): 1.0mm
Reception Slit (Receiving Slit, RS): 1.0mm
The atomic ratio of the oxide sintered body was analyzed by an inductively coupled plasma optical emission spectrometer (ICP-OES, Agilent) using the surface roughness and the remaining oxide sintered body plate for XRD. The results are as follows.
Zn/(In+Sn+Zn)＝0.60
Sn/(Sn+Zn)＝0.20
In/(In+Sn+Zn)＝0.25
(4) Resistance to cracking during sputtering
The sputtering target thus prepared was subjected to pre-sputtering for 1 hour in a G1 sputtering apparatus under conditions of an atmosphere gas of 100% Ar and a sputtering power of 1 kW. Here, the G1 sputtering apparatus is a 1 st generation sputtering apparatus for mass production with a substrate size of about 300mm × 400 mm. After the pre-sputtering, continuous discharge was performed for 2 hours at each power under the film formation conditions shown in table 3, and after the discharge at each power was completed, the chamber was opened, the presence or absence of cracks was visually checked, and the discharge test was repeated by increasing the power, whereby the maximum power at which cracks did not occur was evaluated as crack resistance.
Crack resistance is the maximum sputtering power at which cracks do not occur in the sputtering target. The evaluation results of the crack resistance of each sputtering target are shown in table 1. Further, the relationship between the surface roughness Rz and the crack resistance is shown in the graph of fig. 22.
[ Table 1]
[ Table 2]
[ Table 3]
It is found that the sputtering target using the oxide sintered bodies according to examples 1 to 6 is excellent in crack resistance. It is considered that the surface roughness Rz of the oxide sintered body is less than 2 μm, and the surface roughness is sufficiently small, so that the crack resistance is improved.
It is found that the sputtering targets obtained by using the oxide sintered bodies according to comparative examples 1 to 2 have inferior crack resistance during sputtering to examples 1 to 6. It is considered that the surface roughness Rz of the oxide sintered bodies according to comparative examples 1 to 2 exceeds 3 μm, and therefore, the crack resistance is lowered at a portion where crystal structure exfoliation occurs in the grinding step.
It is found that the sputtering target obtained using the oxide sintered body of comparative example 3 has a lower crack resistance during sputtering than examples 1 to 6. It is considered that since the surface roughness Rz of the oxide sintered body according to comparative example 3 exceeds 2 μm, the crack resistance is lowered at a portion where crystal structure exfoliation occurs in the grinding step.
Description of the reference numerals
1. 1A, 1B, 1C oxide sintered body
3 a back plate.
Claims (11)
1. An oxide sintered body characterized in that,
the surface roughness Rz of the surface of the oxide sintered body is less than 2.0 [ mu ] m.
2. A sputtering target comprising the oxide sintered body according to claim 1.
3. The sputtering target of claim 2,
the oxide sintered body contains an indium element, a tin element, and a zinc element.
4. The sputtering target of claim 3,
the oxide sintered body further contains an element X,
the X element is at least 1 or more element selected from the group consisting of germanium element, silicon element, yttrium element, zirconium element, aluminum element, magnesium element, ytterbium element, and gallium element.
5. The sputtering target according to claim 3 or 4,
the oxide sintered body satisfies the range of atomic composition ratios 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)。
6. the sputtering target according to any one of claims 3 to 5,
the oxide sintered body contains In2O3(ZnO)mHexagonal layered compound represented by the formula and Zn2-xSn1-yInx+yO4The spinel structure compound is represented by (i) m is 2-7, x is 0. ltoreq. x < 2, and y is 0. ltoreq. y < 1.
7. The sputtering target according to any one of claims 2 to 6,
among the grinding traces of the oxide sintered body, a ratio H/L of a depth H to a width L of a grinding trace having a largest depth and a smallest width is less than 0.2.
8. A method for producing a sputtering target, characterized by producing the sputtering target according to any one of claims 2 to 7.
9. The method of manufacturing a sputtering target according to claim 8,
comprising a step of grinding the surface of the oxide sintered body,
the abrasive grain size of the 1 st grinding wheel used for the first grinding is 100 μm or less.
10. The method of manufacturing a sputtering target according to claim 9,
further grinding the surface of the oxide sintered body using a 2 nd grinding wheel having a smaller abrasive grain diameter than the abrasive grain diameter of the 1 st grinding wheel after grinding with the 1 st grinding wheel,
after grinding with the 2 nd grinding wheel, the surface of the oxide sintered body is further ground with a 3 rd grinding wheel having a smaller abrasive grain diameter than that of the 2 nd grinding wheel.
11. The method for manufacturing a sputtering target according to claim 9 or 10,
the feed speed V (m/min) of the object to be ground, the grinding wheel peripheral speed V (m/min) of the 1 st grinding wheel, the depth of cut t (μm), and the abrasive grain diameter d (μm) of the 1 st grinding wheel satisfy the following relational expression (4),
(v/V)1/3×(t)1/6×d＜50…(4)。
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|---|---|---|---|---|
| JPH10310470A (en) * | 1997-05-09 | 1998-11-24 | Mitsubishi Materials Corp | Sputtering target for forming high dielectric film made of barium-strontium-titanium multiple oxide sintered compact |
| CN1690011A (en) * | 2004-04-27 | 2005-11-02 | 住友金属矿山株式会社 | Oxide sintered body, sputtering target, transparent conductive thin film and manufacturing method therefor |
| CN101268026A (en) * | 2005-09-22 | 2008-09-17 | 出光兴产株式会社 | Oxide material and sputtering target |
| JP2009221589A (en) * | 2008-03-19 | 2009-10-01 | Tosoh Corp | Sputtering target consisting of oxide sintered compact |
| JP2011179055A (en) * | 2010-02-26 | 2011-09-15 | Taiheiyo Cement Corp | Sputtering target |
| JP2016060940A (en) * | 2014-09-18 | 2016-04-25 | 日立金属株式会社 | Sputtering target |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4761605B2 (en) * | 2000-05-09 | 2011-08-31 | 株式会社東芝 | Sputtering target |
| CN103469167A (en) * | 2005-09-01 | 2013-12-25 | 出光兴产株式会社 | Sputtering target, transparent conductive film, transparent electrode, electrode substrate, and method for producing same |
| JP4846726B2 (en) | 2005-09-20 | 2011-12-28 | 出光興産株式会社 | Sputtering target, transparent conductive film and transparent electrode |
| WO2017122618A1 (en) | 2016-01-15 | 2017-07-20 | 住友化学株式会社 | Method for preparing amorphous composite metal oxide |
| WO2017158928A1 (en) | 2016-03-14 | 2017-09-21 | Ｊｘ金属株式会社 | Oxide sintered compact |
-
2020
- 2020-02-13 KR KR1020217023913A patent/KR20210129041A/en unknown
- 2020-02-13 WO PCT/JP2020/005667 patent/WO2020170950A1/en active Application Filing
- 2020-02-13 CN CN202080013820.8A patent/CN113677821A/en active Pending
- 2020-02-13 JP JP2021501925A patent/JP7456992B2/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10310470A (en) * | 1997-05-09 | 1998-11-24 | Mitsubishi Materials Corp | Sputtering target for forming high dielectric film made of barium-strontium-titanium multiple oxide sintered compact |
| CN1690011A (en) * | 2004-04-27 | 2005-11-02 | 住友金属矿山株式会社 | Oxide sintered body, sputtering target, transparent conductive thin film and manufacturing method therefor |
| CN101268026A (en) * | 2005-09-22 | 2008-09-17 | 出光兴产株式会社 | Oxide material and sputtering target |
| JP2009221589A (en) * | 2008-03-19 | 2009-10-01 | Tosoh Corp | Sputtering target consisting of oxide sintered compact |
| JP2011179055A (en) * | 2010-02-26 | 2011-09-15 | Taiheiyo Cement Corp | Sputtering target |
| JP2016060940A (en) * | 2014-09-18 | 2016-04-25 | 日立金属株式会社 | Sputtering target |
Also Published As
| Publication number | Publication date |
|---|---|
| JP7456992B2 (en) | 2024-03-27 |
| KR20210129041A (en) | 2021-10-27 |
| TW202041484A (en) | 2020-11-16 |
| WO2020170950A1 (en) | 2020-08-27 |
| JPWO2020170950A1 (en) | 2021-12-23 |
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