WO2014171545A1

WO2014171545A1 - In-Ga-Zn COMPOSITE OXIDE SINTERED COMPACT AND METHOD FOR MANUFACTURING SAME

Info

Publication number: WO2014171545A1
Application number: PCT/JP2014/061098
Authority: WO
Inventors: 邦彦中田; 国孝藤吉
Original assignee: 住友化学株式会社; 福岡県
Priority date: 2013-04-19
Filing date: 2014-04-18
Publication date: 2014-10-23
Also published as: JPWO2014171545A1; TW201509865A

Abstract

This In-Ga-Zn composite oxide sintered compact is represented by the formula In_xGa_yZn_zO_a (wherein, x/(x + y) = 0.2 to 0.8, z/(x + y +z) = 0.1 to 0.5, and a = (3/2)x + (3/2)y + z), the In-Ga-Zn composite oxide sintered compact having a bulk resistance value of less than 1.0 × 10^-3 Ω⋅cm.

Description

In-Ga-Zn composite oxide sintered body and method for producing the same

The present invention relates to an In—Ga—Zn-based composite oxide sintered body, a manufacturing method thereof, and a target.

Thin film transistor (TFT) channel layer in switching elements, drive circuit elements, etc. of electrophoretic display devices, powder transfer display devices, etc., such as liquid crystal display devices, thin film electroluminescence display devices, and organic EL display devices In the past, amorphous silicon films have been mainly used as semiconductor films.
However, in recent years, as this semiconductor film, an oxide semiconductor film made of a metal composite oxide has high mobility and visible light transmittance, and is mainly composed of In—Ga—Zn-based composite oxide (IGZO). The amorphous transparent oxide semiconductor film has the advantage of having higher carrier mobility than the amorphous silicon film, and has attracted attention (Patent Documents 1 to 3).

As a method for producing an amorphous transparent oxide semiconductor film containing IGZO as a main component, a sputtering method is most suitable because it is excellent in mass productivity. The IGZO target used for this sputtering method needs to have a high density. Further, the IGZO target is required to have a low resistance and uniform enough to suppress the occurrence of abnormal discharge even when used in DC sputtering. Therefore, the IGZO target is required to have a high relative density, and in particular, the relative density is required to be close to 100%. Here, the relative density refers to the ratio of the density of the sintered body actually obtained to the theoretical density of the sintered body. Patent Document 4 discloses an IGZO sintered body having a relative density of 99.8%, and Patent Document 5 discloses an IGZO sintered body having a relative density of 100%.

However, there is a problem that the relative density of the IGZO sintered body used for the IGZO target is only about 99.0% at the conventional mass production level.

Conventionally, for example, as described in Patent Documents 6 and 7, the manufacturing method of the IGZO sintered body is mixing, pulverizing, granulating, forming, sintering and (reducing) the raw material powder of the IGZO sintered body. Or the process of mixing, granulation, calcination, grinding | pulverization, shaping | molding, sintering, and (reduction) is required. In order to suppress the volatilization of zinc and indium, sintering is performed under normal pressure sintering in an oxidizing atmosphere such as an air atmosphere or an oxygen atmosphere, or sintering under an oxygen pressure.

In order to reduce the manufacturing cost, that is, to reduce the manufacturing process of the IGZO sintered body and shorten the process as much as possible, the molding process can be omitted if pressure sintering such as hot pressing is employed. However, when the raw powder of the IGZO sintered body is hot pressed at a high temperature of 1000 ° C. or higher, metal In and metal Ga, which are constituent components of the IGZO sintered body, are eluted by the reducing action during the hot pressing process. There is a problem of end. This is because hot press dies and punches are usually made of carbon and thus have a reducing action.
For this reason, a compositional deviation between the composition of the raw material powder of the IGZO sintered body and the composition of the IGZO sintered body, and consequently a compositional deviation between the composition of the film obtained by sputtering of the IGZO target occurs. Moreover, in the hot press process below 1000 degreeC, there existed a problem that a high density IGZO sintered compact was not obtained.

In order to produce an IGZO sintered body having a relative density of 100% described in Patent Document 5, mixing, pulverization, granulation / drying, calcination, pulverization, pulverization, molding (cold) of the raw material powder of the IGZO sintered body After passing through extremely long processes of isostatic pressing and sintering (atmospheric pressure sintering process), it is necessary to perform a capsule-free HIP process, resulting in a high cost.
As described above, although the conventional method can increase the density by performing the capsule-free HIP process on the IGZO sintered body, it has a number of manufacturing processes, and thus has the disadvantage that the productivity is poor and the cost is increased. Furthermore, the bulk resistance value of the obtained IGZO sintered body was as high as 10 ⁻³ Ω · cm or more. For this reason, there is a demand for a method of producing an IGZO sintered body that is uniform, high density, and low resistance (less than 10 ⁻³ Ω · cm) without performing capsule-free HIP treatment.

In addition, the most important point for obtaining a uniform and high-density IGZO sintered body without producing a capsule-free HIP process is to obtain a uniform and high-density IGZO sintered body before entering the sintering process. For the zinc oxide powder, indium oxide powder, and gallium oxide powder used as the raw material, powders (so-called nanoparticles) whose primary particle size is atomized to a level of several tens to 200 nm are used. Thereby, in a sintering process, solid-phase sintering can fully advance between each powder, and can be densified.

However, when the primary particle size reaches a level of several tens of nm to 200 nm, the powder easily scatters and is very difficult to handle, and safety measures for nanomaterials determined by the Ministry of Health, Labor and Welfare must be taken.
In addition, indium oxide has been known to cause carcinogenicity and has been reported to cause pneumonia due to inhalation. Safety issues (see Regulations for the Prevention of Specific Chemical Substance Disorders) have been known in recent years. In order to handle the mixed powder containing the atomized indium oxide powder at the 200 nm level, it is necessary to clear the safety problem from the viewpoint of the problem of nanomaterials and the harmfulness of indium oxide. For that purpose, a large-scale measure is required, and there is a problem that the manufacturing cost is further increased.
Zinc oxide powder and gallium oxide powder, which are raw material powders of IGZO sintered body, have not been reported to cause harmful effects such as carcinogenicity and cause of pneumonia by inhalation, but problems of nanomaterials exist as well. .

JP 2006-165527 A JP 2006-165528 A JP 20061655531 International Publication No. 2010/140548 JP 2010-202450 A JP 2008-280216 A JP 2011-106002 A

The present invention has been made by paying attention to such circumstances, and it is possible to reduce the In—Ga—Zn-based composite oxide (IGZO) target without using so-called nanoparticles that are problematic in handling. An object of the present invention is to provide an IGZO sintered body manufacturing method, an IGZO sintered body, and a target that can be manufactured at a low cost and that can achieve a high relative density of 97 to 100%.

As a result of intensive studies to solve the above-mentioned problems, the present inventors pressurized mixed powder obtained by mixing indium oxide powder, gallium oxide powder and zinc oxide powder having a primary particle size of around 1 μm at a predetermined ratio. Molding, obtaining a molded body, filling this molded body into a capsule container, setting the filling rate of the mixed powder to 50% or more, and performing capsule HIP treatment, thereby suppressing volatilization of indium and zinc, and a sintered body There is almost no deviation between the composition of the mixed powder, which is a raw material, and the intended composition of the sintered body, the relative density is 97 to 100% at a low cost, and the bulk resistance value is less than 1.0 × 10 ⁻³ Ω · cm ( The inventors found for the first time that it was possible to produce a sintered body of the order of 10 ⁻⁴ Ω · cm) and completed the present invention.
Furthermore, it has been found that a large-sized sintered body of 300 mmφ or 300 mm square or more can be produced by the same process as described above without increasing the degreasing step by including a binder in the production of the mixed powder.

That is, the present invention has the following configuration.
(1) Formula: In _x Ga _y Zn _z O _a
[Wherein, x / (x + y) = 0.2 to 0.8, z / (x + y + z) = 0.1 to 0.5, a = (3/2) x + (3/2) y + z]
An In—Ga—Zn-based composite oxide sintered body represented by the formula, wherein the bulk resistance value is less than 1.0 × 10 ⁻³ Ω · cm. Sintered body.
(2) A target used for film formation by sputtering, ion plating, pulsed laser deposition (PLD), or electron beam (EB) vapor deposition, wherein the In—Ga—Zn system according to claim 1 A target obtained by processing a composite oxide sintered body.
(3) Step (a) of pressure-molding a mixed powder containing indium, gallium, zinc, oxygen and satisfying the following mixing conditions and having a primary particle size of 0.6 μm or more to form a molded body: The step of filling the capsule container with the molded body and performing capsule hot isostatic pressing so that the filling ratio of the mixed powder into the capsule container calculated from the following formula is 50% or more (b) In—Ga—Zn-based composite oxide sintered body characterized by comprising:
Mixing conditions: metal atomic ratio In: Ga: Zn = x: y: z, x / (x + y) is 0.2 to 0.8, and z / (x + y + z) is 0.1 to 0.5 Satisfy a relationship.
Filling rate (%) = (packing density of mixed powder into capsule container / theoretical density of sintered body) × 100
(4) The method for producing an In—Ga—Zn-based composite oxide sintered body according to (3), wherein in step (a), indium oxide powder, gallium oxide powder and zinc oxide powder are mixed to obtain a mixed powder. .
(5) In the step (a), the indium oxide powder, the gallium oxide powder and the zinc oxide powder are mixed so as to have a metal atomic ratio of In: Ga: Zn = 1: 1: 1 to obtain a mixed powder. The method for producing an In—Ga—Zn-based composite oxide sintered body according to (3).
(6) In step (a), the mixed powder is pressure-molded so that the density of the molded body is 3.19 g / cm ³ or more. A method for producing a knot.
(7) In the step (a), the indium oxide powder, the gallium oxide powder and the zinc oxide powder are mixed so as to have a metal atomic ratio of In: Ga: Zn = 2: 2: 1 to obtain a mixed powder. The method for producing an In—Ga—Zn-based composite oxide sintered body according to (3).
(8) In the step (a), the mixed powder is pressure-molded so that the density of the molded body is 3.25 g / cm ³ or more. A method for producing a knot.
(9) Production of an In—Ga—Zn-based composite oxide sintered body according to any one of (3) to (8), wherein in step (a), the mixed powder contains a binder and is pressure-molded. Method.
(10) In step (b), the molded body is filled into a capsule container, the filling rate of the mixed powder is 50% or more, debinding treatment and vacuum degassing treatment of the capsule container are performed at the same time, and then the capsule is hot, etc. The method for producing an In—Ga—Zn-based composite oxide sintered body according to (9), wherein the pressure treatment is performed.
(11) In-Ga— according to any one of the above (3) to (10), wherein the molded body is subjected to capsule hot isostatic pressing at a sintering temperature of 1000 to 1400 ° C. in step (b). A method for producing a Zn-based composite oxide sintered body.
(12) The In—Ga—Zn according to any one of the above (3) to (11), wherein in step (b), an inert gas is used as a pressure medium and the molded body is subjected to capsule hot isostatic pressing. Of producing a composite oxide of a composite oxide.
(13) The In—Ga—Zn-based composite according to any one of (3) to (12), wherein in step (b), the capsule is subjected to hot isostatic pressing with a pressing force of 50 MPa or more. Manufacturing method of oxide sinter.

According to the present invention, an IGZO sintered body having a relative density of 97 to 100% can be produced with a simple and few manufacturing process, high productivity and low cost. Further, according to the present invention, volatilization of indium and zinc is suppressed, and there is almost no deviation between the composition of the mixed powder that is a raw material of the IGZO sintered body and the target composition of the IGZO sintered body.
Furthermore, since it is not necessary to use mixed powder that has been pulverized to nanoparticles (several tens of nm to 200 nm), handling of the mixed powder is easy, and there is no problem with the safety of nanomaterials. This is not necessary, can realize low cost, and can be a sintered body having a bulk resistance value of the order of 10 ⁻⁴ Ω · cm (low resistance).
By using this manufacturing method of the present invention, it is possible to provide an IGZO target for sputtering having a relative density of 97 to 100% with no composition deviation at low cost. By using this target for sputtering film formation, abnormalities such as arcing can be obtained. No discharge, no long-term continuous film formation, nodules on the surface, no adverse effect, good transparency that becomes active layer part of thin film transistor in active matrix driving liquid crystal display element and organic EL display element A semiconductor IGZO film can be manufactured.

(Manufacturing method of IGZO sintered body)
The manufacturing method of the IGZO sintered body of the present invention includes the step (a) of pressing a predetermined mixed powder to form a molded body, and filling the molded body into a capsule container, and hot isostatic pressing of the capsule (Capsule HIP) process (b). This makes it possible to set the relative density of the IGZO sintered body to 97 to 100%. Moreover, this manufacturing process is a conventional manufacturing process 1 (a series of manufacturing steps of mixing, calcining, coarse pulverization, fine pulverization, granulation, molding, sintering, and capsule-free HIP treatment) or a conventional manufacturing process 2 Compared with (a series of manufacturing steps of mixing, pulverization, granulation, calcination, pulverization, pulverization, molding, sintering, and capsule-free HIP treatment), the number of steps is simple. Moreover, since the primary particle size of the mixed powder is 0.6 μm or more, which is generally easy to handle for manufacturing a normal oxide sintered body, there is no problem of safety of the nanomaterial, and it is large. There is no need to take any safety measures. Therefore, it can be manufactured at low cost.

Here, the relative density is a ratio of the density of the sintered body actually obtained to the theoretical density of the sintered body, and is obtained from the following formula.
Relative density (%) = (density of sintered body / theoretical density of sintered body) × 100
The density of the sintered body in the above formula can be measured by the evaluation method described in the examples. The theoretical density of the sintered body in the above formula is, in principle, a value obtained by multiplying the single-component density of each metal oxide that is the raw material of the sintered body by the mixing weight ratio of each metal oxide powder and taking the sum, For example, when the sintered body is made of indium oxide, gallium oxide, and zinc oxide, it can be obtained from the following formula.
Theoretical density of sintered body = (Indium oxide simple substance density × mixing weight ratio) + (Gallium oxide simple substance density × mixing weight ratio) + (Zinc oxide simple substance density × mixing weight ratio)

However, if the information on single-phase crystals with the same metal atom ratio as the mixed powder metal atom ratio is described on the JCPDS (Joint Committee Committee of Powder Diffraction Standards) card, the theoretical density of the crystal described on the JCPDS card Can be used as the theoretical density of the sintered body in the above formula.

As a specific example, when indium oxide powder, gallium oxide powder, and zinc oxide powder are mixed so that the atomic ratio of indium, gallium, and zinc is In: Ga: Zn = 1: 1: 1, JCPDS Since the card contains information on the single-phase crystal of InGaZnO ₄ (In: Ga: Zn = 1: 1: 1), the theoretical density of the single-phase crystal of InGaZnO ₄ described in the JCPDS card (No. 381104) Let (6.379 g / cm ³ ) be the theoretical density of the sintered body in the above formula.
As another specific example, indium oxide powder, gallium oxide powder, and zinc oxide powder are mixed so that the atomic ratio of indium, gallium, and zinc is In: Ga: Zn = 2: 2: 1. Represents the theoretical density (6.495 g / cm ³ ) of the single phase crystal of In ₂ Ga ₂ ZnO ₇ (In: Ga: Zn = 2: 2: 1) described in the JCPDS card (No. 381097) in the above formula. The theoretical density of the sintered body.
If the proportion of metal atoms in the mixed powder and the proportion of metal atoms in the single-phase crystal described in the JCPDS card do not match, if the deviation is within 5%, the single atom described in the JCPDS card The theoretical density of the phase crystal is defined as the theoretical density of the sintered body in the above formula.

<Process (a)>
(Mixed powder)
The mixed powder contains indium, gallium, zinc and oxygen. Indium, gallium, zinc and oxygen are typically 99% or more of the total atoms constituting the mixed powder.

The mixed powder can be obtained by mixing each raw material powder at a predetermined ratio. The raw material powder is composed of indium-containing powder, gallium-containing powder, and zinc-containing powder.
The purity of these raw material powders is usually 2N (99% by mass) or more, preferably 3N (99.9% by mass) or more, and particularly preferably 4N (99.99% by mass) or more. If the purity is lower than 2N, the thin film characteristics may be deteriorated during sputtering film formation.
The primary particle size of each raw material powder is generally 0.6 μm or more, which is generally easy to handle, and preferably 1 to 5 μm or less. If the primary particle size of each raw material powder is 0.6 μm or more, the primary particle size of the mixed powder is 0.6 μm or more.

The primary particle size refers to the 50% cumulative volume fraction in the particle size distribution measured by the laser diffraction / scattering method (hereinafter the same).

(Indium-containing powder)
Examples of the indium-containing powder include indium oxide powder and indium hydroxide powder, and indium oxide powder is preferable because it is easily sintered and by-products remain difficult to remain. Indium oxide generally has a bixbite structure, and may have a structure in which an indium oxide powder having a bixbite structure is preliminarily calcined in a reducing atmosphere to cause oxygen deficiency. The tap density of the indium oxide powder before molding differs from the primary particle size and particle size distribution, but is often 1.95 g / cm ³ or less. The indium oxide powder preferably has no calcining history.

Here, the tap density is based on JIS K5101, when a fixed volume container is filled with powder by natural dropping, and then the container is further subjected to a constant vibration (tapping) and the volume of the powder disappears. Is defined as the mass of the powder per unit volume. Note that the powder mass per unit volume when the powder is filled into the container of a certain volume by natural dropping and the inner volume is the volume is called the bulk density, and the tap density is generally 1.1% of the bulk density. The value is about 1.3 times.

(Gallium-containing powder)
Examples of the gallium-containing powder include gallium oxide powder and gallium hydroxide powder. Gallium oxide may have a crystal structure of α-Ga ₂ O ₃ or β-Ga ₂ O ₃ . Alternatively, the structure may be preliminarily calcined in a reducing atmosphere and oxygen deficient. The tap density of the gallium oxide powder before molding differs from the primary particle size and particle size distribution, but is often 1.45 g / cm ³ or less. The gallium oxide powder preferably has no calcining history.

(Zinc-containing powder)
Examples of the zinc-containing powder include zinc oxide powder and zinc hydroxide powder. As the zinc oxide powder, a powder of ZnO or the like having a wurtzite structure is usually used, and further, this ZnO may be preliminarily calcined in a reducing atmosphere to contain oxygen deficiency. Further, the BET specific surface area is not particularly limited. The tap density of the zinc oxide powder before molding differs from the primary particle size and particle size distribution, but is often 1.12 g / cm ³ or less. The zinc oxide powder preferably has no calcining history.
Examples of the zinc hydroxide powder include amorphous Zn (OH) ₂ powder and Zn (OH) ₂ powder having a crystal structure.

(mixture)
In the step (a), for example, the indium-containing powder, the gallium-containing powder, and the zinc-containing powder are uniformly mixed so as to satisfy the following mixing condition. Thereby, it can be set as the IGZO sintered compact of the composition mentioned later.
Mixing conditions: metal atomic ratio In: Ga: Zn = x: y: z, x / (x + y) is 0.2 to 0.8, and z / (x + y + z) is 0.1 to 0.5 Satisfy a relationship.
When using indium oxide powder, gallium oxide powder and zinc oxide powder as raw material powders, the weight ratio of indium oxide powder: gallium oxide powder: zinc oxide powder is approximately 44.2: 29.9: 25.9 (moles). Mix uniformly so that the ratio is In: Ga: Zn = 1: 1: 1) or 50.8: 34.3: 14.9 (Molar ratio In: Ga: Zn = 2: 2: 1) Is preferably performed. Thus, it is possible to IGZO sintered body which represented the characteristic favorable InGaZnO ₄ and In _₂ Ga ₂ ZnO ₇ to be described later.

The mixing method is not particularly limited as long as it can be uniformly mixed, and dry mixing or wet mixing (ball mill or the like) is performed using a super mixer, an intensive mixer, a Henschel mixer, an automatic mortar, or the like. In wet mixing, for example, the mixed powder and an aqueous solvent are mixed, and the resulting slurry is sufficiently mixed by a wet ball mill using a hard ZrO ₂ ball or a vibration mill, followed by solid-liquid separation, drying, and granulation. The mixing time when a wet ball mill, vibration mill or bead mill is used is preferably about 12 to 78 hours. Known methods may be employed for solid-liquid separation, drying, and granulation. The aqueous solvent contains water as a main component and may be water alone, or may be a mixture of water and alcohol such as methanol or ethanol.
If uniform mixing is insufficient, each component segregates in the manufactured target, and the resistance distribution of the target becomes non-uniform. That is, a high resistance region and a low resistance region exist depending on the part of the target, which causes abnormal discharge such as arcing due to charging in the high resistance region during sputtering film formation.

(binder)
In the present invention, an organic binder may be mixed with the mixed powder. The organic binder is used to improve handling properties, and is particularly necessary when producing a large sintered body having a side of 300 mm or more or a diameter of 300 mm or more.
The amount of the organic binder added is preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight with respect to 100 parts by weight of the mixed powder.

When using an organic binder, the raw material powder and the organic binder are mixed to form a mixed powder, and pressure molded to form a pressure molded body. And before performing a capsule HIP process to this press-molded body, a binder removal process (degreasing) is performed. This debinding treatment may be performed, for example, after the pressure molded body is filled in the capsule container and before the capsule container is vacuum degassed, or after the pressure molded body is filled in the capsule container, the vacuum degassing is performed. Although the process may be performed simultaneously with the treatment, the latter is preferable because a process only for degreasing is not necessary in producing the IGZO sintered body. Even when an organic binder is used, an IGZO sintered body can be produced in the same manner as when no organic binder is used, except that the organic binder is mixed and the binder removal treatment is performed. it can.

As the organic binder, known binders can be used. For example, butyral resin, polyvinyl alcohol, acrylic resin, poly α-methylstyrene, ethyl cellulose, polymethyl lactate, (poly) vinyl butyral, (poly) vinyl acetate, (poly ) Vinyl alcohol, polyethylene, polystyrene, polybutadiene, (poly) vinyl pyrrolidone, polyamide, polyethylene oxide, polypropylene oxide, polyacrylamide, polymethacrylate and various acrylic polymers and their copolymers and terpolymers, methylcellulose, ethylcellulose, hydroxyethylcellulose, nitro Examples thereof include resins such as cellulose and derivatives thereof.

The method of mixing the organic binder is not particularly limited, but for example, a raw material powder, an organic binder, a solvent capable of dissolving the organic binder, and a solvent to form a slurry are obtained, and the obtained slurry Can be mixed by wet mixing, followed by a known drying process. In addition, you may mix an organic binder with the mixed powder which mixed each raw material powder.
In order to press-mold a powder obtained by mixing a raw material powder and an organic binder, it may be performed in the same manner as in the case of producing a molded body without using an organic binder.

When filling the capsule container with the pressure-molded body molded using an organic binder and then performing the debinding process before vacuum degassing of the capsule container, for example, in any atmosphere, inert in an air atmosphere Heating may be performed at least at 400 ° C. or more and about 500 to 700 ° C. in an arbitrary atmosphere such as an atmosphere.
When the capsule container is filled with a molded body molded using an organic binder, and the capsule container is subjected to vacuum degassing and debindering at the same time, after filling the molded body into the capsule container, an exhaust pipe is connected to the capsule container. In order to remove the adsorbed moisture, the upper lid is welded and heated to about 450 to 700 ° C., and at the same time, vacuum degassing is performed until the degree of vacuum in the capsule container is 1.33 × 10 ⁻² Pa or less. Thereby, the heat degassing process and the debinding process can be performed simultaneously, and the debinding process can be performed without increasing the manufacturing process without increasing the manufacturing process because the process only for degreasing is not required. Large sintered bodies (300 mm square, 300 mmφ or more) can be produced without particularly increasing the number of processes.

(Pressure molding)
In order to press-mold the mixed powder, for example, a uniaxial press, a cold isostatic press (CIP), or the like can be used. When molding, a uniaxial press and a cold isostatic press (CIP) may be used in combination.

In the case of uniaxial pressing, the pressing pressure when forming the mixed powder is at least 30 MPa or more and less than 100 MPa, more preferably 40 MPa or more. If it is less than 30 MPa, there is a possibility that a stable press-molded product cannot be produced. If it is 100 MPa or more, the molded product may be brittle and easily cracked.
For example, in order to make the density of the molded body 3.19 g / cm ³ or more, it is preferably 40 to 90 MPa, more preferably 50 to 80 MPa.

In the case of cold isostatic pressing (CIP), it is at least 50 MPa or more and less than 300 MPa, more preferably 100 MPa or more. If it is less than 50 MPa, there is a possibility that a stable press-molded product cannot be produced. If the pressure is 300 MPa or more, the molded body may be easily crushed.
For example, to make the density of the molded body 3.19 g / cm ³ or more, it is preferably 100 to 250 MPa, more preferably 150 to 200 MPa.

(Molded body)
The shape of the molded body is not particularly limited, but a cylindrical shape and a rectangular shape are preferable in order to apply pressure evenly and contract evenly during capsule HIP processing. The size of the molded body is not particularly limited, and is preferably a size corresponding to the size of the capsule container filled with the molded body.

The density of the molded body is preferably 50% or more of the theoretical density value of the sintered body made of the mixed powder. For example, when manufacturing an IGZO sintered body represented by InGaZnO ₄ , a molded body made of a mixed powder mixed so that the atomic ratio of indium, gallium, and zinc is In: Ga: Zn = 1: 1: 1. In this case, it is preferably 3.19 g / cm ³ or more, more preferably 3.8 to 6.3 g / cm ³ . Also, for example, when manufacturing an IGZO sintered body represented by In ₂ Ga ₂ ZnO ₇ , mixing was performed so that the atomic ratio of indium, gallium, and zinc was In: Ga: Zn = 2: 2: 1. In the case of a molded body made of a mixed powder, the density of the molded body is preferably 3.25 g / cm ³ or more, more preferably 3.8 to 6.4 g / cm ³ .
If the density of the molded body is within the above range, the molded body can be filled into the capsule container without losing its shape, so that the filling rate of the mixed powder described later can be increased to 50% or more. The shrinkage ratio of the capsule container by the treatment can be 50% or less.

The density of the molded body can be determined from the volume calculated from the measured value and the measured weight of the molded body by directly measuring the length of the molded body. For example, if the shape of the molded body is a cylindrical shape, the diameter and height of the molded body are directly measured to determine the volume of the cylindrical molded body, the weight is measured, and the density is calculated from the weight and volume. Can be calculated. In addition, when the molded body contains an organic binder and the binder removal treatment of the molded body is performed simultaneously with the vacuum deaeration process of the capsule container, the density of the molded body is a value obtained by subtracting the weight of the organic binder from the measured weight. The weight of the molded body can be obtained from the weight of the molded body and the volume calculated from the measured value. In addition, when the molded body contains an organic binder, and the debinding treatment of the molded body is performed before the vacuum degassing processing of the capsule container, the density of the molded body after the debinding process is the density of the molded body described above. It is preferable to be within the preferable range, and can be obtained in the same manner as the density of the molded body described above.

<Step (b)>
In the step (b), as described above, the filling rate of the mixed powder calculated from the formula: (packing density of the mixed powder into the capsule container / theoretical density of the sintered body) × 100 is 50% or more. After the molded body thus obtained is filled into a capsule container, the capsule container is hermetically sealed and subjected to capsule HIP treatment.

The theoretical density of the sintered body in the above formula can be obtained in the same manner as the theoretical density of the sintered body in the above formula for calculating the relative density.
The filling density of the mixed powder in the above formula is the mass of the molded body relative to the internal volume of the capsule container when the molded body is filled in the capsule container. The smaller the difference between the size of the molded body and the size in the capsule container, the closer the density value of the mixed powder is to the density value of the molded body. If the molded body does not fit in the capsule container because the size of the molded body is larger than the size of the capsule container, the molded body may be placed in the capsule container after the size is adjusted by mechanical processing such as polishing. In addition, when the molded body contains an organic binder and the binder removal treatment of the molded body is performed at the same time as the vacuum deaeration process of the capsule container, the mass of the molded body when determining the packing density of the mixed powder is the measured weight It is the value which deducted the weight of the organic binder from. In addition, when the molded body contains an organic binder, and the binder removal treatment of the molded body is performed before the vacuum degassing of the capsule container, the mass of the molded body when determining the packing density of the mixed powder is the desorption. It is the weight of the molded body measured after the binder treatment.

By filling the mixed powder in the capsule container and setting the filling rate of the mixed powder to 50% or more, the shrinkage ratio of the capsule container by the capsule HIP method can be reduced to 50% or less. Therefore, the mixed powder can be pressure-sintered without destroying the capsule container, and a high-density IGZO sintered body in which volatilization of indium and zinc derived from the mixed powder is suppressed can be obtained.
The shrinkage rate of the capsule container is represented by the following formula.
Shrinkage rate of capsule container (%) = [1− (inner volume of capsule container after capsule HIP treatment / inner volume of capsule container before capsule HIP process)] × 100

Filling the molded body into the capsule container means producing a pressure molded body by CIP, uniaxial press or the like, and transferring all the molded body into the capsule container so that the molded body does not collapse (for example, carefully Use a spatula shape). At this time, if the molded body contains the above-described organic binder, even a large molded body can be transferred into the capsule container without breaking the shape. If the filling rate of the mixed powder can be 50% or more, two or more molded bodies may be filled in the capsule container.
In addition, when the molded body is transferred to the capsule container, the molded body tends to collapse. Therefore, the powder to be filled directly into the capsule container is placed and uniaxial press molding is performed so that the filling ratio of the mixed powder is 50% or more. May be produced.

(Capsule container)
As the material of the capsule container, any material can be used as long as the molded body can be sufficiently vacuum-sealed and can be sufficiently deformed at the sintering temperature in the capsule HIP processing but does not have a risk of bursting. For example, iron, stainless steel, aluminum, Stainless steel, tantalum, niobium, copper, nickel, etc. are used. Moreover, a capsule container can be properly used according to the sintering temperature of the capsule HIP process. For example, when the sintering temperature of the capsule HIP treatment is in a low temperature region (1000 ° C. or lower), a capsule container made of copper, nickel, or aluminum can be used. When the sintering temperature is 1000 ° C. to 1350 ° C., iron and stainless capsule containers are used. Tantalum and niobium capsule containers are used in the higher temperature range than the sintering temperature. Depending on the sintering temperature, a capsule container of aluminum, iron or stainless steel is preferable because of its low cost.

The shape and dimensions of the capsule container are not particularly limited, and may be matched to a desired shape of the sintered body. For example, a cylindrical shape, a rectangular shape, or the like can be used.
The size of the capsule container may be larger or smaller than the size of the molded body as long as the filling ratio of the mixed powder can be 50% or more when the molded body is filled in the capsule container. . If it is a cylindrical shape or a rectangular shape, the uniformity (relative density, composition) of the IGZO sintered body is maintained.
The wall thickness of the capsule container is preferably 1.5 mm to 5 mm. Within this range, the capsule container can be easily softened and deformed, and can shrink following the sintered body as the sintering reaction proceeds.

(Vacuum degassing treatment)
When performing the capsule HIP process, a vacuum deaeration process is performed in which the molded body is filled in a capsule container and the capsule container is evacuated. By this evacuation, the gas and adsorbed moisture adhering to the mixed powder can be removed.
The heating temperature of the capsule container when evacuating is preferably 100 ° C. or higher and 600 ° C. or lower. When the molded body contains an organic binder, the heating temperature of the capsule container when evacuating is about 450 to 700 ° C. as described above.
In evacuation of the capsule container, the pressure in the capsule container is reduced to 1.33 × 10 ⁻² Pa or less while heating the capsule container. If the pressure in the capsule container after evacuation exceeds 1.33 × 10 ^-2 Pa, the gas and adsorbed moisture adhering to the mixed powder will not be sufficiently removed. There is a risk that no union is obtained.

When performing capsule HIP treatment, connect the exhaust pipe to the capsule container, perform heating and evacuation as described above, and if the pressure in the capsule container is 1.33 × 10 ⁻² Pa or less, The exhaust pipe connected to the capsule container is closed, and the capsule container is sealed.

(Capsule HIP processing)
Capsule HIP processing is performed by placing the vacuum-sealed capsule container in a HIP apparatus.
In the capsule HIP treatment, the mixed powder (molded body) inside the capsule container is sintered by applying pressure to the capsule container itself using an inert gas at high temperature and high pressure as a pressure medium. When the capsule HIP process is performed in an oxidizing atmosphere, the capsule container itself is oxidized, so that the mechanical strength of the capsule container itself is greatly reduced, and the capsule container may burst during the capsule HIP process. As a result, there is a possibility that a high density IGZO sintered body cannot be obtained. Since the mixed powder is a closed space confined in the capsule container by vacuum sealing, there is no volatilization of indium and zinc, and no composition shift occurs.

The capsule HIP treatment conditions may be any conditions as long as the relative density of the sintered body can be 97 to 100%. For example, the capsule HIP treatment conditions may be set as follows.
As the gas as the pressure medium, an inert gas such as nitrogen or argon is preferably used. The pressure applied to the capsule container is preferably 50 MPa or more. The sintering time in the capsule HIP treatment is preferably 1 hour or longer. The sintering temperature is 1000 to 1400 ° C, more preferably 1100 to 1300 ° C. If the sintering temperature in the capsule HIP treatment is within the above range, the material of the capsule container is in a temperature region where the material is softened and deformed. The pressure can be applied to 100%. In particular, the sintering temperature is preferably 1000 ° C. to 1400 ° C. and the pressure is 50 MPa or more for 1 hour or more. Note that when the temperature is less than 1000 ° C. and the pressure is less than 50 MPa under the capsule HIP processing conditions, the relative density of the obtained sintered body is as low as less than 90%.

(IGZO sintered body)
The In—Ga—Zn-based composite oxide sintered body (IGZO sintered body) of the present invention contains indium (In), gallium (Ga), zinc (Zn), and oxygen (O) as constituent elements, and is typically In addition, 99% or more of the atoms are composed of indium, gallium, zinc, and oxygen, which can be expressed by the following formula.
Formula: In _x Ga _y Zn _z O _a
[Wherein, x / (x + y) is 0.2 to 0.8, z / (x + y + z) is 0.1 to 0.5, a = (3/2) x + (3/2) y + z]
For example, when x: y: z = 1: 1: 1, it can be expressed as InGaZnO _4, and when x: y: z = 2: 2: 1, it can be expressed as In ₂ Ga ₂ ZnO _7. it can. Among these, these two compositions are preferable in terms of characteristics.
Moreover, the IGZO sintered body of the present invention does not contain the impurity metal element M (Sn, Zr, Ti, Mo, Si, Cr, W, Ge, V, Mn). That is, the content [M / (In + Ga + Zn + M): weight ratio] of the impurity metal element M in the IGZO sintered body of the present invention is less than 10 ppm.
The content of the impurity metal element M in the IGZO sintered body can be measured by the evaluation method described in the examples.

If the atomic ratio x / (x + y) of indium to the total amount of indium and gallium exceeds 0.8, the carrier concentration of the film obtained by sputtering film formation is too high, and the thin film transistor having the film as an active layer The on / off ratio, which is an important indicator of characteristics, is deteriorated. On the other hand, when the atomic ratio x / (x + y) of indium is less than 0.2, the carrier concentration of the film obtained by sputtering film formation becomes too low, and the mobility of the film also decreases. This is not preferable in terms of device characteristics.
Moreover, when the atomic ratio z / (x + y + z) of zinc with respect to the total amount of indium, gallium and zinc exceeds 0.5, the stability of the film obtained by sputter deposition, moisture resistance, etc. Will deteriorate. On the other hand, when the atomic ratio z / (x + y + z) of zinc is less than 0.1, the amorphousness of the film obtained by sputtering film formation becomes weak and crystallization becomes easy.
The crystallized film has a large in-plane variation in film characteristics, resulting in a large variation in element characteristics. Furthermore, the decrease in the atomic ratio z / (x + y + z) of zinc is an increase in the ratio of the total amount of In and Ga to the total amount of indium, gallium and zinc. These two types of metals are compared with zinc metal. Since it is expensive, the cost of the IGZO sintered body is increased.
In the present specification, “a” describes the case where the stoichiometric composition coincides with the stoichiometric composition, but the oxygen amount in the IGZO sintered body deviates somewhat from the stoichiometric composition and is somewhat oxygen deficient. Therefore, the present invention includes such an IGZO sintered body having oxygen vacancies.

The bulk resistance value of the obtained sintered body is preferably less than 1.0 × 10 ⁻³ Ω · cm, more preferably 8 × 10 ⁻⁴ Ω · cm or less, and further preferably 7 × 10 ⁻⁴ Ω · cm. Since it is a sintered body excellent in electrical conductivity, it is particularly suitable as a target in the DC sputtering method, and it is possible to efficiently form a uniform amorphous semiconductor film stably and at high speed without abnormal discharge. it can.
The bulk resistance value of the IGZO sintered body can be measured by the evaluation method described in the examples.

(target)
The target of the present invention is used for film formation by sputtering, ion plating, pulsed laser deposition (PLD) or electron beam (EB) vapor deposition, and is an IGZO sintered body obtained by the manufacturing method of the present invention. Is processed. Since the target of the present invention has a high density and is usually 97% or more, preferably 99% or more, and more preferably 100% as a relative density, abnormal deposition hardly occurs when forming a film by sputtering, and the film is stably formed. can do.
In addition, although the solid material used in the film formation may be referred to as “tablet”, in the present invention, these are referred to as “target”.

When the target of the present invention is used for sputtering film formation as a sputtering target, the relative density of the IGZO sintered body is usually 97% or more, preferably 99% or more, more preferably 100%. As the time elapses, the frequency of nodule generation and the frequency of abnormal discharge can be dramatically reduced, the sputter production efficiency is improved, and the film properties obtained are excellent.

The target of the present invention is formed by processing the above-described IGZO sintered body into a predetermined shape and a predetermined dimension. When the target is manufactured, for example, the target is 152.4φ × 5 tmm by performing cylindrical grinding on the outer periphery of the IGZO sintered body obtained as described above and surface grinding on the surface side. Further, for example, an indium alloy or the like can be bonded to a copper backing plate as a bonding metal to obtain a sputtering target.
A processing method in particular is not restrict | limited, What is necessary is just to employ | adopt a well-known method suitably. For example, the target of the present invention can be obtained by subjecting the IGZO sintered body to surface grinding or the like, and then cutting it to a predetermined dimension and then attaching it to a support base. Further, if necessary, a plurality of IGZO sintered bodies may be divided into divided shapes to form a large-area target (composite target).

(Transparent semiconductor film)
By sputtering an object such as a substrate using the IGZO sintered body or the target of the present invention, a transparent semiconductor film having favorable characteristics as a channel layer of a thin film transistor exhibiting stable semiconductor characteristics can be formed.
The film thickness of the transparent semiconductor film is preferably 45 nm or less in terms of a semiconductor having a high mobility and a low S value.

Examples of the sputtering method include a DC sputtering method, an AC sputtering method, an RF magnetron sputtering method, an electron beam evaporation method, an ion plating method, and the like, and a DC sputtering method is preferable.
For example, in the case of the DC sputtering method, the pressure in the chamber during sputtering is usually 0.1 to 2.0 MPa, and preferably 0.3 to 0.8 MPa. Closing electric power per unit area of the target surface during sputtering, if for example, the DC sputtering method is generally 0.5 ~ 6.0W / cm ^2, is preferably 1.0 ~ 5.0W / cm ² . Examples of the carrier gas at the time of sputtering include oxygen, helium, argon, xenon, krypton, and the like, and preferably a mixed gas of argon and oxygen. The flow ratio of argon: oxygen in the mixed gas of argon and oxygen is usually Ar: O ₂ = 100: 0 to 80:20, preferably 100: 0 to 90:10. As the substrate, glass, resin (PET, PES, or the like) can be used. The film thickness at the time of film formation is preferably 1 to 45 nm, more preferably 3 to 30 nm, and particularly preferably 5 to 20 nm.

Hereinafter, description will be made based on examples and comparative examples. In addition, a present Example is an example of this invention to the last, This invention is not restrict | limited at all by this example, Various modifications other than the Example contained in this invention are included.

(Example 1)
Indium oxide powder (In ₂ O ₃ , manufactured by Soekawa Richemical Co., Ltd., primary particle size: 1 μm), gallium oxide powder (Ga ₂ O ₃ , manufactured by Yamanaka Futec Co., Ltd., primary particle size: 1.5 μm), Zinc oxide powder (ZnO, manufactured by Hakusuitec Co., Ltd., primary particle size: 1.5 μm) is weighed so that the atomic ratio of indium element, gallium element and zinc element is 1: 1: 1, and an automatic mortar For 1 hour to obtain a mixed powder.

Next, this mixed powder was press-molded by applying a pressure of 300 MPa with a cold isostatic press and cut to obtain a cylindrical molded body having a diameter of 115 mm and a height of 40 mm. The density of the cylindrical molded body was 3.61 g / cm ³ .
The density of the molded body was determined by directly measuring the molded body and calculating the volume calculated from the measured diameter and height, and the measured weight of the molded body.

<Manufacture of IGZO sintered body>
The cylindrical molded body is transferred to a capsule container (outer diameter: 121 mm, inner diameter: 115 mm, height inside the container: 40 mm) made of stainless steel (SUS304) so that the molded body does not collapse, and is placed in the capsule container. When filled (filled), the packing density of the mixed powder was 3.61 g / cm ³ , and the theoretical density of the sintered body was 6.379 g / cm ³ , so the packing ratio of the mixed powder was 56.6. %.
The packing density and the theoretical density of the sintered body were obtained from the following formula.
Filling density = Molded body weight / Capsule container internal volume The theoretical density of the sintered body is the crystal phase corresponding to the 1: 1 atomic ratio of indium, gallium and zinc elements. Has information on a single-phase crystal called InGaZnO ₄ (JCPDS card number: 381104), and the theoretical density of this single-phase crystal described in the JCPDS card was adopted.

After filling the capsule container with the mixed powder, the exhaust pipe was welded to the upper lid, and then the upper lid and the capsule container were welded. In order to confirm the soundness of the welded part of the capsule container, a He leak test was performed. The amount of leakage at this time was 1 × 10 ⁻⁹ Pa · m ³ / sec or less. Then, after evacuating the capsule container for 7 hours at 550 ° C., confirm that the inside of the capsule container is 1.33 × 10 ⁻² Pa or less, close the exhaust pipe, and seal the capsule container Went. The sealed capsule container was inserted into a HIP processing apparatus (manufactured by Kobe Steel, Ltd.) and subjected to capsule HIP processing. The capsule HIP treatment was performed under a treatment condition of 4 hours using Ar gas (purity: 99.9%) at a temperature of 1220 ° C. and a pressure of 100 MPa as a pressure medium.

After the capsule HIP treatment, the capsule container was removed to obtain a cylindrical IGZO sintered body (1). When the size of the sintered body (1) was directly measured, it was 95.1 mm in diameter and 33.1 mm in height.
The relative density of this IGZO sintered body (1) was 100%, and the bulk resistance value of the sintered body was 6.2 × 10 ⁻⁴ Ω · cm. Further, when the IGZO sintered body (1) was observed with an electron microscope, it was a dense sintered body with almost no voids.
The relative density was determined as shown in the following formula.
Relative density = 100 × [(density of sintered body) / (theoretical density of sintered body)]
The theoretical density of the sintered body was the theoretical density of InGaZnO ₄ (JCPDS card number: 381104) described in the JCPDS card.
The density of the sintered body was measured by a length measurement method.
The bulk resistance value was measured by a four-terminal four-probe method using a resistivity meter (“LORESTA-GP, MCP-T610” manufactured by Mitsubishi Chemical Corporation). Specifically, four needle-like electrodes are placed on a straight line on the IGZO sintered body (1), and a constant current is passed between the outer two probes and the inner two probes, and the inner two probes. The potential difference generated between them was measured to determine the resistance.

The obtained IGZO sintered body (1) was subjected to surface grinding, outer circumference grinding, and surface polishing to obtain a sintered body having a diameter of 50.8 mmφ and a thickness of 3 mm.
When the obtained IGZO sintered body (1) was analyzed with an ICP (high frequency inductively coupled plasma) analyzer (“SPS5000” manufactured by SEIKO Co., Ltd.), the atomic ratio of In, Ga, and Zn was In: Ga: Zn = 1: 1: 1. Since the atomic ratio of In, Ga, and Zn in this IGZO sintered body (1) is not shifted at all from the charged composition, In: Ga: Zn = 1: 1: 1, the volatilization of indium and zinc is There wasn't.
Also, an ICP analyzer for each content of impurity metal elements M (Sn, Zr, Ti, Mo, Si, Cr, W, Ge, V, Mn) expected to be included in the IGZO sintered body (1) The analysis was done. From the analysis results, the content ratio [M / (In + Ga + Zn + M): weight ratio] of the impurity metal element M to the component metals (In, Ga, Zn) of the IGZO sintered body (1) was calculated. All the contents were less than 10 ppm.

This IGZO sintered body (1) was bonded using indium solder using a copper plate as a backing plate to obtain a sputtering target. Using this, a transparent semiconductor film was formed on a transparent substrate (non-alkali glass substrate) by a DC sputtering method to obtain a transparent semiconductor substrate. That is, in the sputtering apparatus (“E-200” manufactured by Canon Anelva Engineering Co., Ltd.), the target and the transparent base material (quartz glass substrate) were respectively installed, and Ar gas (purity 99.9995% or more, Ar pure) Gas = 5N) is introduced at 12 sccm, DC sputtering is performed for 10 hours under conditions of a pressure of 0.5 Pa, an input power of 3.8 W / cm ² per unit area of the target surface, and a substrate temperature of room temperature. In addition, a stable amorphous transparent semiconductor film with high carrier mobility was formed.
As a result, almost no nodules were generated on the target surface, and almost no abnormal discharge occurred during film formation. Specifically, the number of abnormal discharges that occurred during film formation was within 3 times per hour, and there was never a shutdown of the sputtering apparatus due to the occurrence of abnormal discharges. The number of abnormal discharges was detected by a micro arc monitor.

From the above, since there is no volatilization of indium and zinc, the composition of the mixed powder, which is the raw material of the IGZO sintered body (1), and the composition of the obtained IGZO sintered body (1) do not deviate at all and are extremely high. This is an IGZO sintered body having a density (relative density: 100%) and low resistance. As a result, even if DC sputtering is performed using a target obtained by processing the IGZO sintered body (1), the operation of the sputtering apparatus is stopped. The film could be formed stably without any problems.

As described above, since the particle size of the mixed powder is not a nanoparticle size by a very simple short manufacturing process, a high-density (relative density: 100%) sintered body could be produced without any problem of nanomaterials.

(Example 2)
Indium oxide powder (In ₂ O ₃ , manufactured by Soekawa Richemical Co., Ltd., primary particle size: 1 μm), gallium oxide powder (Ga ₂ O ₃ , manufactured by Yamanaka Futec Co., Ltd., primary particle size: 1.5 μm), Zinc oxide powder (ZnO, manufactured by Hakusuitec Co., Ltd., primary particle size: 1.5 μm) is weighed so that the atomic ratio of indium element, gallium element and zinc element is 2: 2: 1, and an automatic mortar For 1 hour.
Subsequently, it was press-molded by applying a pressure of 300 MPa in a cold isostatic press and cut to obtain a cylindrical molded body having a diameter of 115 mmφ and a height of 40 mm. The density of the cylindrical molded body was 3.56 g / cm ³ .
The density of the molded body was determined by directly measuring the molded body and calculating the volume calculated from the measured diameter and height, and the measured weight of the molded body.

<Manufacture of IGZO sintered body>
The cylindrical molded body is transferred to a capsule container (outer diameter: 121 mm, inner diameter: 115 mm, height inside the container: 40 mm) made of stainless steel (SUS304) so that the molded body does not collapse, and is placed in the capsule container. When filled (filled), the packing density of the mixed powder was 3.56 g / cm ³ , and the theoretical density of the sintered body was 6.495 g / cm ³ , so the packing ratio of the mixed powder was 54.8. %.
The packing density and the theoretical density of the sintered body were obtained from the following formula.
Filling density = Molded body weight / Capsule container inner volume The theoretical density of the sintered body is the crystal phase corresponding to the number of atoms of indium element, gallium element and zinc element is 2: 2: 1. _₂ Ga ₂ ZnO ₇ (JCPDS card number: 381097) contains information single phase crystal, it was adopted theoretical density of the single-phase crystal described in JCPDS card.

After the capsule HIP treatment, the capsule container was removed to obtain a cylindrical IGZO sintered body (2). When the size of the sintered body (2) was directly measured, it was 94.2 mm in diameter and 32.8 mm in height.
The relative density of this IGZO sintered body (2) was 100%, and the bulk resistance value of the sintered body was measured in the same manner as in Example 1. As a result, it was 4.2 × 10 ⁻⁴ Ω · cm. . Further, when the IGZO sintered body (2) was observed with an electron microscope, it was a dense sintered body with almost no voids.
The relative density was determined as shown in the following formula.
Relative density = 100 × [(density of sintered body) / (theoretical density of sintered body)]
The theoretical density of the sintered body is In _₂ Ga ₂ ZnO ₇ according to JCPDS card (JCPDS card number: 381097) was adopted theoretical density.
The density of the sintered body was measured by a length measurement method.

The obtained IGZO sintered body (2) was subjected to surface grinding, outer periphery grinding and then surface polishing to obtain a sintered body having a diameter of 50.8 mm and a thickness of 3 mm.
When the obtained IGZO sintered body (2) was analyzed with an ICP (high frequency inductively coupled plasma) analyzer (“SPS5000” manufactured by SEIKO Co., Ltd.), the atomic ratio of In, Ga, and Zn was In: Ga: Zn = 2: 2: 1. Since the atomic ratio of In, Ga, and Zn in this IGZO sintered body (2) is not shifted at all from the charged composition, In: Ga: Zn = 2: 2: 1, the volatilization of indium and zinc is There wasn't.

The IGZO sintered body (2) was bonded using indium solder using a copper plate as a backing plate to obtain a sputtering target. Using this, a transparent semiconductor film was formed on a transparent substrate (non-alkali glass substrate) by a DC sputtering method to obtain a transparent semiconductor substrate. That is, in the sputtering apparatus (“E-200” manufactured by Canon Anelva Engineering Co., Ltd.), the target and the transparent base material (quartz glass substrate) were respectively installed, and Ar gas (purity 99.9995% or more, Ar pure) Gas = 5N) is introduced at 12 sccm, DC sputtering is performed for 10 hours under conditions of a pressure of 0.5 Pa, an input power of 3.8 W / cm ² per unit area of the target surface, and a substrate temperature of room temperature. In addition, a stable amorphous transparent semiconductor film with high carrier mobility was formed. As a result, almost no nodules were generated on the target surface, and almost no abnormal discharge occurred during film formation. Specifically, the number of abnormal discharges that occurred during film formation was within 3 times per hour, and there was never a shutdown of the sputtering apparatus due to the occurrence of abnormal discharges. The number of abnormal discharges was detected by a micro arc monitor.

From the above, since there is no volatilization of indium and zinc, the composition of the mixed powder, which is the raw material of the IGZO sintered body (2), and the composition of the obtained IGZO sintered body (2) do not deviate at all and are extremely high. IGZO sintered body having a density (relative density: 100%) and low resistance. As a result, even if DC sputtering is performed using a target obtained by processing the IGZO sintered body (2), the operation of the sputtering apparatus is stopped. The film could be formed stably without any problems.

(Example 3)
Indium oxide powder (In ₂ O ₃ , manufactured by Soekawa Richemical Co., Ltd., primary particle size: 1 μm), gallium oxide powder (Ga ₂ O ₃ , manufactured by Yamanaka Futec Co., Ltd., primary particle size: 1.5 μm), Zinc oxide powder (ZnO, manufactured by Hakusuitec Co., Ltd., primary particle size: 1.5 μm) was mixed with a mixed powder composed of an indium element, a gallium element, and a zinc element at a 1: 1: 1 ratio and ethyl cellulose (sum) (Made by Kokuyo Pure Chemical Co., Ltd.) and water were mixed at a ratio of mixed powder: organic binder (ethylcellulose) = 98.5: 1.5 (weight ratio) to obtain an aqueous slurry.
The aqueous slurry thus adjusted was put in a resin pot and wet mixed by a wet ball mill mixing method. This wet mixing was performed using hard ZrO ₂ balls as balls and mixing time of 18 hours.

Next, the mixed aqueous slurry is taken out, and the water is volatilized with an evaporator by sieving the balls. After that, drying is performed at 100 ° C. for 3 hours with a hot air dryer, and then with a cold isostatic press. It was pressure-molded by applying a pressure of 300 MPa and cut to obtain a cylindrical molded body having a diameter of 300 mmφ and a height of 150 mm. The density of the cylindrical molded body was 3.60 g / cm ³ .
The density of the molded body was obtained by directly measuring the length of the molded body and calculating the volume calculated from the measured diameter and height and the weight obtained by subtracting the weight of the organic binder from the measured weight of the molded body.

<Manufacture of IGZO sintered body>
The cylindrical molded body is transferred to a capsule container (outer diameter: 308 mm, inner diameter: 300 mm, height inside the container: 150 mm) made of stainless steel (SUS304) so that the molded body does not collapse, and is placed in the capsule container. When filled up (filled) and the packing density was determined in the same manner as in Example 1, the packing density of the mixed powder was 3.60 g / cm ³ , and the theoretical density of the sintered body was 6.379 g / cm ³ . As a result, the filling rate of the mixed powder was 56.4%.

After filling the capsule container with the mixed powder, the exhaust pipe was welded to the upper lid, and then the upper lid and the capsule container were welded. In order to confirm the soundness of the welded part of the capsule container, a He leak test was performed. The amount of leakage at this time was 1 × 10 ⁻⁹ Pa · m ³ / sec or less. After that, the capsule container was evacuated at 600 ° C. for 7 hours to completely remove the binder degreasing and the adsorbed water of the molded body, and the inside of the capsule container became 1.33 × 10 ⁻² Pa or less. After confirming, the exhaust pipe was closed and the capsule container was sealed. The sealed capsule container was inserted into a HIP processing apparatus (manufactured by Kobe Steel, Ltd.) and subjected to capsule HIP processing. The capsule HIP treatment was performed under a treatment condition of 4 hours using Ar gas (purity: 99.9%) at a temperature of 1220 ° C. and a pressure of 100 MPa as a pressure medium.

After the capsule HIP treatment, the capsule container was removed to obtain a cylindrical IGZO sintered body (3). When the size of the IGZO sintered body (3) was directly measured, the diameter was 248.7 mmφ and the height was 124.4 mm. The relative density of the IGZO sintered body (3) was as in Example 1. When determined in the same manner, it was 100%, and the bulk resistance value of the sintered body was 6.2 × 10 ⁻⁴ Ω · cm as measured in the same manner as in Example 1. Further, when the sintered body (3) was observed with an electron microscope, it was a dense sintered body with almost no pores.

The obtained IGZO sintered body (3) was ground and then subjected to surface polishing to obtain a sintered body having a diameter of 50.8 mmφ and a thickness of 3 mm.
When the obtained IGZO sintered body (3) was analyzed with an ICP (high frequency inductively coupled plasma) analyzer (“SPS5000” manufactured by SEIKO Co., Ltd.), the atomic ratio of In, Ga, and Zn was In: Ga: Zn = 1: 1: 1. Since the atomic ratio of In, Ga, and Zn in this IGZO sintered body (3) is not shifted at all from the charged composition, In: Ga: Zn = 1: 1: 1, the volatilization of indium and zinc is There wasn't.

This IGZO sintered body (3) was bonded using indium solder using a copper plate as a backing plate to obtain a sputtering target. Using this, a transparent semiconductor film was formed on a transparent substrate (non-alkali glass substrate) by a DC sputtering method to obtain a transparent semiconductor substrate. That is, in the sputtering apparatus (“E-200” manufactured by Canon Anelva Engineering Co., Ltd.), the target and the transparent base material (quartz glass substrate) were respectively installed, and Ar gas (purity 99.9995% or more, Ar pure) Gas = 5N) is introduced at 12 sccm, DC sputtering is performed for 10 hours under conditions of a pressure of 0.5 Pa, an input power of 3.8 W / cm ² per unit area of the target surface, and a substrate temperature of room temperature. In addition, a stable amorphous transparent semiconductor film with high carrier mobility was formed. As a result, almost no nodules were generated on the target surface, and almost no abnormal discharge occurred during film formation. Specifically, the number of abnormal discharges that occurred during film formation was within 3 times per hour, and there was never a shutdown of the sputtering apparatus due to the occurrence of abnormal discharges. The number of abnormal discharges was detected by a micro arc monitor.

From the above, since there is no volatilization of indium and zinc, the composition of the mixed powder as the raw material of the IGZO sintered body (3) and the composition of the obtained IGZO sintered body (3) are not displaced at all, and are extremely high. This is an IGZO sintered body having a density (relative density: 100%) and low resistance. As a result, even if DC sputtering is performed using a target obtained by processing the IGZO sintered body (3), the operation of the sputtering apparatus is stopped. The film could be formed stably without any problems.

Example 4
Indium oxide powder (In ₂ O ₃ , manufactured by Soekawa Richemical Co., Ltd., primary particle size: 1 μm), gallium oxide powder (Ga ₂ O ₃ , manufactured by Yamanaka Futec Co., Ltd., primary particle size: 1.5 μm), A mixed powder comprising zinc oxide powder (ZnO, manufactured by Hakutech Co., Ltd., primary particle size: 1.5 μm) having an atomic ratio of indium element, gallium element and zinc element of 2: 2: 1, and ethyl cellulose ( Wako Pure Chemical Industries, Ltd.) and water were mixed at a ratio of mixed powder: organic binder (ethylcellulose) = 98.5: 1.5 (weight ratio) to obtain an aqueous slurry.
The aqueous slurry thus adjusted was put in a resin pot and wet mixed by a wet ball mill mixing method. This wet mixing was performed using hard ZrO ₂ balls as balls and mixing time of 18 hours.

Next, the mixed aqueous slurry is taken out, and the water is volatilized with an evaporator by sieving the balls. After that, drying is performed at 100 ° C. for 3 hours with a hot air dryer, and then with a cold isostatic press. It was pressure-molded by applying a pressure of 300 MPa and cut to obtain a cylindrical molded body having a diameter of 450 mmφ and a height of 150 mm. The density of the cylindrical molded body was 3.52 g / cm ³ .
The density of the molded body was obtained by directly measuring the length of the molded body and calculating the volume calculated from the measured diameter and height and the weight obtained by subtracting the weight of the organic binder from the measured weight of the molded body.

<Manufacture of IGZO sintered body>
The cylindrical molded body is transferred to a capsule container (outer diameter: 458 mm, inner diameter: 450 mm, height inside the container: 150 mm) made of stainless steel (SUS304) so that the molded body does not collapse, and is placed in the capsule container When filled (filled) and the packing density was determined in the same manner as in Example 1, the packing density of the mixed powder was 3.52 g / cm ³ and the theoretical density of the sintered body was 6.495 g / cm ³ . For this reason, the filling rate of the mixed powder was 54.2%.

After the capsule HIP treatment, the capsule container was removed to obtain a cylindrical IGZO sintered body (4). When the size of the IGZO sintered body (4) was directly measured, the diameter was 366.8 mmφ and the height was 122.3 mm. The relative density of the IGZO sintered body (4) was as in Example 2. When determined in the same manner, it was 100%, and the bulk resistance value of the sintered body was 4.2 × 10 ⁻⁴ Ω · cm as measured in the same manner as in Example 1. Further, when the sintered body (4) was observed with an electron microscope, it was a dense sintered body with almost no pores.

The obtained IGZO sintered body (4) was ground and then subjected to surface polishing to obtain a sintered body having a diameter of 50.8 mmφ and a thickness of 3 mm.
When the obtained IGZO sintered body (4) was analyzed with an ICP (high frequency inductively coupled plasma) analyzer (“SPS5000” manufactured by SEIKO Co., Ltd.), the atomic ratio of In, Ga, and Zn was In: Ga: Zn = 2: 2: 1. Since the atomic ratio of In, Ga, and Zn in this IGZO sintered body (4) is not shifted at all from the charged composition, In: Ga: Zn = 2: 2: 1, the volatilization of indium and zinc is There wasn't.

This IGZO sintered body (4) was bonded using indium solder using a copper plate as a backing plate to obtain a sputtering target. Using this, a transparent semiconductor film was formed on a transparent substrate (non-alkali glass substrate) by a DC sputtering method to obtain a transparent semiconductor substrate. That is, in the sputtering apparatus (“E-200” manufactured by Canon Anelva Engineering Co., Ltd.), the target and the transparent base material (quartz glass substrate) were respectively installed, and Ar gas (purity 99.9995% or more, Ar pure) Gas = 5N) is introduced at 12 sccm, DC sputtering is performed for 10 hours under conditions of a pressure of 0.5 Pa, an input power of 3.8 W / cm ² per unit area of the target surface, and a substrate temperature of room temperature. In addition, a stable amorphous transparent semiconductor film with high carrier mobility was formed. As a result, almost no nodules were generated on the target surface, and almost no abnormal discharge occurred during film formation. Specifically, the number of abnormal discharges that occurred during film formation was within 3 times per hour, and there was never a shutdown of the sputtering apparatus due to the occurrence of abnormal discharges. The number of abnormal discharges was detected by a micro arc monitor.

From the above, since there is no volatilization of indium and zinc, the composition of the mixed powder that is the raw material of the IGZO sintered body (4) and the composition of the obtained IGZO sintered body (4) are not displaced at all, and are extremely high. This is an IGZO sintered body having a density (relative density: 100%) and low resistance. As a result, even if DC sputtering is performed using a target obtained by processing the IGZO sintered body (4), the operation of the sputtering apparatus stops. The film could be formed stably without any problems. Furthermore, an extremely high-density and large-sized sintered body (4) could be produced by simultaneously carrying out vacuum degassing treatment and debinding treatment of the capsule container (without passing through a process only for degreasing).

(Example 5)
Indium oxide powder (In ₂ O ₃ , manufactured by Soekawa Richemical Co., Ltd., primary particle size: 1 μm), gallium oxide powder (Ga ₂ O ₃ , manufactured by Rare Metal Co., Ltd., primary particle size: 3.0 μm) Zinc oxide powder (ZnO, manufactured by Hakusuitec Co., Ltd., primary particle size: 1.5 μm) was weighed so that the atomic ratio of indium element, gallium element, and zinc element was 1: 1: 1. Dry mixing was performed in a mortar for 1 hour.

Subsequently, it was press-molded by applying a pressure of 300 MPa in a cold isostatic press and cut to obtain a cylindrical molded body having a diameter of 115 mmφ and a height of 40 mm. The density of the cylindrical molded body was 3.56 g / cm ³ .
The density of the molded body was determined by directly measuring the molded body and calculating the volume calculated from the measured diameter and height, and the measured weight of the molded body.

<Manufacture of IGZO sintered body>
The cylindrical molded body is transferred to a capsule container (outer diameter: 121 mm, inner diameter: 115 mm, height inside the container: 40 mm) made of stainless steel (SUS304) so that the molded body does not collapse, and is placed in the capsule container. When filled (filled), the packing density of the mixed powder was 3.46 g / cm ³ , and the theoretical density of the sintered body was 6.379 g / cm ³ , so the packing ratio of the mixed powder was 54. 2%.
The packing density and the theoretical density of the sintered body were obtained from the following formula.
Filling density = Molded body weight / Capsule container internal volume The theoretical density of the sintered body is the crystal phase corresponding to the 1: 1 atomic ratio of indium, gallium and zinc elements. Has information on a single-phase crystal called InGaZnO ₄ (JCPDS card number: 381104), and the theoretical density of this single-phase crystal described in the JCPDS card was adopted.

After the capsule HIP treatment, the capsule container was removed to obtain a cylindrical IGZO sintered body (5). When the size of the sintered body (5) was directly measured, it was 93.7 mm in diameter and 32.6 mm in height.
When the relative density of this IGZO sintered body (5) was determined in the same manner as in Example 1, it was 100%, and the bulk resistance value of the sintered body was measured in the same manner as in Example 1. It was 9 × 10 ⁻⁴ Ω · cm. Further, when the IGZO sintered body (5) was observed with an electron microscope, it was a dense sintered body with almost no voids.

The obtained IGZO sintered body (5) was subjected to surface grinding, outer periphery grinding and then surface polishing to obtain a sintered body having a diameter of 50.8 mm and a thickness of 3 mm.
When the obtained IGZO sintered body (5) was analyzed with an ICP (high frequency inductively coupled plasma) analyzer (“SPS5000” manufactured by SEIKO Co., Ltd.), the atomic ratio of In, Ga, and Zn was In: Ga: Zn = 1: 1: 1. Since the atomic ratio of In, Ga, and Zn in this IGZO sintered body (5) is not shifted at all from the charged composition, In: Ga: Zn = 1: 1: 1, the volatilization of indium and zinc is There wasn't.
Further, the ICP analyzer is also used for each content of impurity metal elements M (Sn, Zr, Ti, Mo, Si, Cr, W, Ge, V, Mn) that are expected to be included in the IGZO sintered body (5). The analysis was done. From the analysis results, the content ratio [M / (In + Ga + Zn + M): weight ratio] of the impurity metal element M to the component metals (In, Ga, Zn) of the IGZO sintered body (5) was calculated. All the contents were less than 10 ppm.

This IGZO sintered body (5) was bonded using indium solder using a copper plate as a backing plate to obtain a sputtering target. Using this, a transparent semiconductor film was formed on a transparent substrate (non-alkali glass substrate) by a DC sputtering method to obtain a transparent semiconductor substrate. That is, in the sputtering apparatus (“E-200” manufactured by Canon Anelva Engineering Co., Ltd.), the target and the transparent base material (quartz glass substrate) were respectively installed, and Ar gas (purity 99.9995% or more, Ar pure) Gas = 5N) is introduced at 12 sccm, DC sputtering is performed for 10 hours under conditions of a pressure of 0.5 Pa, an input power of 3.8 W / cm ² per unit area of the target surface, and a substrate temperature of room temperature. In addition, a stable amorphous transparent semiconductor film with high carrier mobility was formed. As a result, almost no nodules were generated on the target surface, and almost no abnormal discharge occurred during film formation. Specifically, the number of abnormal discharges that occurred during film formation was within 3 times per hour, and there was never a shutdown of the sputtering apparatus due to the occurrence of abnormal discharges. The number of abnormal discharges was detected by a micro arc monitor.

From the above, since there is no volatilization of indium and zinc, the composition of the mixed powder, which is the raw material of the IGZO sintered body (5), and the composition of the obtained IGZO sintered body (5) are not displaced at all and are extremely high. This is an IGZO sintered body having a density (relative density: 100%) and low resistance. As a result, even if DC sputtering is performed using a target obtained by processing the IGZO sintered body (5), the operation of the sputtering apparatus stops. The film could be formed stably without any problems.

(Example 6)
Indium oxide powder (In ₂ O ₃ , manufactured by Soekawa Rikagaku Co., Ltd., primary particle size: 1 μm), gallium oxide powder (Ga ₂ O ₃ , manufactured by Rare Metal Co., Ltd., primary particle size: 3.0 μm) The zinc oxide powder (ZnO, manufactured by Hakusuitec Co., Ltd., primary particle size: 1.5 μm) is weighed so that the atomic ratio of indium element, gallium element and zinc element is 2: 2: 1, and automatic Dry mixing was performed in a mortar for 1 hour.
Subsequently, it was press-molded by applying a pressure of 300 MPa in a cold isostatic press and cut to obtain a cylindrical molded body having a diameter of 115 mmφ and a height of 40 mm. The density of the cylindrical molded body was 3.47 g / cm ³ .
The density of the molded body was determined by directly measuring the molded body and calculating the volume calculated from the measured diameter and height, and the measured weight of the molded body.

<Manufacture of IGZO sintered body>
The cylindrical molded body is transferred to a capsule container (outer diameter: 121 mm, inner diameter: 115 mm, height inside the container: 40 mm) made of stainless steel (SUS304) so that the molded body does not collapse, and is placed in the capsule container. When filled (filled), the packing density of the mixed powder was 3.47 g / cm ³ , and the theoretical density of the sintered body was 6.495 g / cm ³ , so the packing ratio of the mixed powder was 53.4. %.
The packing density and the theoretical density of the sintered body were obtained from the following formula.
Filling density = Molded body weight / Capsule container inner volume The theoretical density of the sintered body is the crystal phase corresponding to the number of atoms of indium element, gallium element and zinc element is 2: 2: 1. There is information on single-phase crystals of ₂ Ga ₂ ZnO ₇ (JCPDS card number: 381097), and the theoretical density of this single-phase crystal described in the JCPDS card was adopted.

After the capsule HIP treatment, the capsule container was removed to obtain a cylindrical IGZO sintered body (6). When the size of the sintered body (6) was directly measured, it was 93.4 mm in diameter and 32.5 mm in height.
The relative density of this IGZO sintered body (6) was 100%, and the bulk resistance value of the sintered body was 5.2 × 10 ⁻⁴ Ω · cm as measured in the same manner as in Example 1. . Further, when the IGZO sintered body (6) was observed with an electron microscope, it was a dense sintered body with almost no voids.
The relative density was determined as shown in the following formula.
Relative density = 100 × [(density of sintered body) / (theoretical density of sintered body)]
The theoretical density of the sintered body was the theoretical density of In ₂ Ga ₂ ZnO ₇ (JCPDS card number: 381097) described in the JCPDS card.
The density of the sintered body was measured by a length measurement method.

The obtained IGZO sintered body (6) was subjected to surface grinding, outer periphery grinding and then surface polishing to obtain a sintered body having a diameter of 50.8 mm and a thickness of 3 mm.
When the obtained IGZO sintered body (6) was analyzed with an ICP (high frequency inductively coupled plasma) analyzer (“SPS5000” manufactured by SEIKO Co., Ltd.), the atomic ratio of In, Ga, and Zn was In: Ga: Zn = 2: 2: 1. Since the atomic ratio of In, Ga, and Zn in this IGZO sintered body (6) is not shifted at all from the charged composition, In: Ga: Zn = 2: 2: 1, the volatilization of indium and zinc is There wasn't.

This IGZO sintered body (6) was bonded using indium solder using a copper plate as a backing plate to obtain a sputtering target. Using this, a transparent semiconductor film was formed on a transparent substrate (non-alkali glass substrate) by a DC sputtering method to obtain a transparent semiconductor substrate. That is, in the sputtering apparatus (“E-200” manufactured by Canon Anelva Engineering Co., Ltd.), the target and the transparent base material (quartz glass substrate) were respectively installed, and Ar gas (purity 99.9995% or more, Ar pure) Gas = 5N) is introduced at 12 sccm, DC sputtering is performed for 10 hours under conditions of a pressure of 0.5 Pa, an input power of 3.8 W / cm ² per unit area of the target surface, and a substrate temperature of room temperature. In addition, a stable amorphous transparent semiconductor film with high carrier mobility was formed. As a result, almost no nodules were generated on the target surface, and almost no abnormal discharge occurred during film formation. Specifically, the number of abnormal discharges that occurred during film formation was within 3 times per hour, and there was never a shutdown of the sputtering apparatus due to the occurrence of abnormal discharges. The number of abnormal discharges was detected by a micro arc monitor.

From the above, since there is no volatilization of indium and zinc, the composition of the mixed powder that is the raw material of the IGZO sintered body (6) and the composition of the obtained IGZO sintered body (6) are not displaced at all, and are extremely high. This is an IGZO sintered body having a density (relative density: 100%) and low resistance. As a result, even if DC sputtering is performed using a target obtained by processing the IGZO sintered body (6), the operation of the sputtering apparatus is stopped. The film could be formed stably without any problems.

(Example 7)
Indium oxide powder (In ₂ O ₃ , manufactured by High Purity Chemical Laboratory Co., Ltd., primary particle size: 4.0 μm), gallium oxide powder (Ga ₂ O ₃ , manufactured by rare metal Co., Ltd.), primary particle size : 3.0 μm), zinc oxide powder (ZnO, manufactured by Hakusuitec Co., Ltd., primary particle size: 1.5 μm), the atomic ratio of indium element, gallium element and zinc element is 1: 1: 1. The mixed powder, ethyl cellulose (manufactured by Wako Pure Chemical Industries, Ltd.) and water are mixed so that the ratio of mixed powder: organic binder (ethyl cellulose) = 98.5: 1.5 (weight ratio) is obtained to obtain an aqueous slurry. It was.
The aqueous slurry thus adjusted was put in a resin pot and wet mixed by a wet ball mill mixing method. This wet mixing was performed using hard ZrO ₂ balls as balls and mixing time of 18 hours.

Next, the mixed aqueous slurry is taken out, and the water is volatilized with an evaporator by sieving the balls. After that, drying is performed at 100 ° C. for 3 hours with a hot air dryer, and then with a cold isostatic press. It was pressure-molded by applying a pressure of 300 MPa and cut to obtain a cylindrical molded body having a diameter of 450 mmφ and a height of 150 mm. The density of the cylindrical molded body was 3.47 g / cm ³ .
The density of the molded body was obtained by directly measuring the length of the molded body and calculating the volume calculated from the measured diameter and height and the weight obtained by subtracting the weight of the organic binder from the measured weight of the molded body.

<Manufacture of IGZO sintered body>
The cylindrical molded body is transferred to a capsule container (outer diameter: 458 mm, inner diameter: 450 mm, height inside the container: 150 mm) made of stainless steel (SUS304) so that the molded body does not collapse. When filled (filled) and the packing density was determined in the same manner as in Example 1, the packing density of the mixed powder was 3.47 g / cm ³ , and the theoretical density of the sintered body was 6.379 g / cm ³ . As a result, the filling rate of the mixed powder was 54.4%.

After the capsule HIP treatment, the capsule container was removed to obtain a cylindrical IGZO sintered body (7). When the size of the IGZO sintered body (7) was directly measured, the diameter was 367.0 mmφ and the height was 122.3 mm. The relative density of the IGZO sintered body (7) was as in Example 1. When determined in the same manner, it was 100%, and the bulk resistance value of the sintered body was 8.8 × 10 ⁻⁴ Ω · cm as measured in the same manner as in Example 1. Further, when the sintered body (7) was observed with an electron microscope, it was a dense sintered body with almost no pores.

The obtained IGZO sintered body (7) was ground and then subjected to surface polishing to obtain a sintered body having a diameter of 50.8 mmφ and a thickness of 3 mm.
When the obtained IGZO sintered body (7) was analyzed with an ICP (high frequency inductively coupled plasma) analyzer (“SPS5000” manufactured by SEIKO Co., Ltd.), the atomic ratio of In, Ga, and Zn was In: Ga: Zn = 1: 1: 1. Since the atomic ratio of In, Ga, and Zn in this IGZO sintered body (7) is not shifted at all from the charged composition, In: Ga: Zn = 1: 1: 1, the volatilization of indium and zinc is There wasn't.

This IGZO sintered body (7) was bonded using indium solder using a copper plate as a backing plate to obtain a sputtering target. Using this, a transparent semiconductor film was formed on a transparent substrate (non-alkali glass substrate) by a DC sputtering method to obtain a transparent semiconductor substrate. That is, in the sputtering apparatus (“E-200” manufactured by Canon Anelva Engineering Co., Ltd.), the target and the transparent base material (quartz glass substrate) were respectively installed, and Ar gas (purity 99.9995% or more, Ar pure) Gas = 5N) is introduced at 12 sccm, DC sputtering is performed for 10 hours under conditions of a pressure of 0.5 Pa, an input power of 3.8 W / cm ² per unit area of the target surface, and a substrate temperature of room temperature. In addition, a stable amorphous transparent semiconductor film with high carrier mobility was formed. As a result, almost no nodules were generated on the target surface, and almost no abnormal discharge occurred during film formation. Specifically, the number of abnormal discharges that occurred during film formation was within 3 times per hour, and there was never a shutdown of the sputtering apparatus due to the occurrence of abnormal discharges. The number of abnormal discharges was detected by a micro arc monitor.

From the above, since there is no volatilization of indium and zinc, the composition of the mixed powder, which is the raw material of the IGZO sintered body (7), and the composition of the obtained IGZO sintered body (7) do not deviate at all and are extremely high. This is an IGZO sintered body having a density (relative density: 100%) and a low resistance. As a result, even if DC sputtering is performed using a target obtained by processing the IGZO sintered body (7), the operation of the sputtering apparatus is stopped. The film could be formed stably without any problems. Furthermore, an extremely high-density and large-sized sintered body (7) could be produced by simultaneously performing the vacuum degassing treatment and the debinding treatment of the capsule container (without going through a process only for degreasing).

(Example 8)
Indium oxide powder (In ₂ O ₃ , manufactured by Soekawa Rikagaku Co., Ltd., primary particle size: 1 μm), gallium oxide powder (Ga ₂ O ₃ , manufactured by Rare Metal Co., Ltd., primary particle size: 1.0 μm) Zinc oxide powder (ZnO, manufactured by Hakusuitec Co., Ltd., primary particle size: 1.5 μm) is mixed with a mixed powder composed of an indium element, a gallium element, and a zinc element having an atomic ratio of 2: 2: 1 and ethylcellulose ( Wako Pure Chemical Industries, Ltd.) and water were mixed at a ratio of mixed powder: organic binder (ethylcellulose) = 98.5: 1.5 (weight ratio) to obtain an aqueous slurry.
The aqueous slurry thus adjusted was put in a resin pot and wet mixed by a wet ball mill mixing method. This wet mixing was performed using hard ZrO ₂ balls as balls and mixing time of 18 hours.

Next, the mixed aqueous slurry is taken out, and the water is volatilized with an evaporator by sieving the balls. After that, drying is performed at 100 ° C. for 3 hours with a hot air dryer, and then with a cold isostatic press. It was pressure-molded by applying a pressure of 300 MPa and cut to obtain a cylindrical molded body having a diameter of 450 mmφ and a height of 150 mm. The density of the cylindrical molded body was 3.58 g / cm ³ .
The density of the molded body was obtained by directly measuring the length of the molded body and calculating the volume calculated from the measured diameter and height and the weight obtained by subtracting the weight of the organic binder from the measured weight of the molded body.

<Manufacture of IGZO sintered body>
The cylindrical molded body is transferred to a capsule container (outer diameter: 458 mm, inner diameter: 450 mm, height inside the container: 150 mm) made of stainless steel (SUS304) so that the molded body does not collapse, and is placed in the capsule container When filled (filled) and the packing density was determined in the same manner as in Example 1, the packing density of the mixed powder was 3.58 g / cm ³ and the theoretical density of the sintered body was 6.495 g / cm ³ . As a result, the filling rate of the mixed powder was 55.1%.

After the capsule HIP treatment, the capsule container was removed to obtain a cylindrical IGZO sintered body (8). When the size of the IGZO sintered body (8) was directly measured, the diameter was 369.0 mmφ and the height was 123.0 mm. The relative density of the IGZO sintered body (8) was as in Example 2. When determined in the same manner, it was 100%, and the bulk resistance value of the sintered body was 4.9 × 10 ⁻⁴ Ω · cm as measured in the same manner as in Example 1. Further, when the sintered body (8) was observed with an electron microscope, it was a dense sintered body with almost no pores.

The obtained IGZO sintered body (8) was ground and then subjected to surface polishing to obtain a sintered body having a diameter of 50.8 mmφ and a thickness of 3 mm.
When the obtained IGZO sintered body (8) was analyzed with an ICP (high frequency inductively coupled plasma) analyzer (“SPS5000” manufactured by SEIKO Co., Ltd.), the atomic ratio of In, Ga, and Zn was In: Ga: Zn = 2: 2: 1. Since the atomic ratio of In, Ga, and Zn in this IGZO sintered body (8) is not shifted at all from the charged composition, In: Ga: Zn = 2: 2: 1, the volatilization of indium and zinc is There wasn't.

This IGZO sintered body (8) was bonded using indium solder using a copper plate as a backing plate to obtain a sputtering target. Using this, a transparent semiconductor film was formed on a transparent substrate (non-alkali glass substrate) by a DC sputtering method to obtain a transparent semiconductor substrate. That is, in the sputtering apparatus (“E-200” manufactured by Canon Anelva Engineering Co., Ltd.), the target and the transparent base material (quartz glass substrate) were respectively installed, and Ar gas (purity 99.9995% or more, Ar pure) Gas = 5N) is introduced at 12 sccm, DC sputtering is performed for 10 hours under conditions of a pressure of 0.5 Pa, an input power of 3.8 W / cm ² per unit area of the target surface, and a substrate temperature of room temperature. In addition, a stable amorphous transparent semiconductor film with high carrier mobility was formed. As a result, almost no nodules were generated on the target surface, and almost no abnormal discharge occurred during film formation. Specifically, the number of abnormal discharges that occurred during film formation was within 3 times per hour, and there was never a shutdown of the sputtering apparatus due to the occurrence of abnormal discharges. The number of abnormal discharges was detected by a micro arc monitor.

From the above, since there is no volatilization of indium and zinc, the composition of the mixed powder that is the raw material of the IGZO sintered body (8) and the composition of the obtained IGZO sintered body (8) are not displaced at all and are extremely high. This is an IGZO sintered body having a density (relative density: 100%) and a low resistance. As a result, even if DC sputtering is performed using a target obtained by processing the IGZO sintered body (8), the operation of the sputtering apparatus is stopped. The film could be formed stably without any problems. Furthermore, an extremely high-density and large-sized sintered body (8) could be produced by simultaneously performing the vacuum degassing treatment and the debinding treatment of the capsule container (without going through a process only for degreasing).

(Comparative Example 1)
<Manufacture of IGZO sintered body>
Indium oxide powder having a tap density of 1.95 g / cm ³ (In ₂ O ₃ , primary particle size: 1 μm, manufactured by Soekawa Rikagaku Co., Ltd.), gallium oxide powder having a tap density of 1.39 g / cm ³ (Ga ₂ O ₃ , manufactured by Yamanaka Hutech Co., Ltd., primary particle size: 1.5 μm, zinc oxide powder having a tap density of 1.02 g / cm ³ (ZnO, manufactured by Hakusui Tech Co., Ltd.) Primary particle size: 1. 5 μm), a mixed powder weighed so that the atomic ratio of indium element, gallium element and zinc element is 1: 1: 1. Molecular weight: 200,000), ethanol, and acetone for dissolving polypropylene carbonate, mixed powder: organic binder (polypropylene carbonate) 97: 3 were mixed such that the proportion of the (weight ratio) to obtain a slurry. The slurry thus prepared was placed in a resin pot and wet mixed by a wet ball mill mixing method. This wet mixing was performed using hard ZrO ₂ balls as balls and mixing time of 18 hours. Next, the slurry after wet mixing was taken out, and the balls were sieved and the solvent was removed by an evaporator to obtain a mixed powder. The tap density of indium oxide powder, gallium oxide powder, and zinc oxide powder is based on JIS K5101, and each powder is filled with vibration while applying vibration to a graduated cylinder of a predetermined size until there is no volume change of each powder. And evaluated.

When the obtained mixed powder was filled in the same capsule container as used in Example 1 while applying vibration until the volume of the mixed powder disappeared, the tap density was 1.58 g / cm ³ , which was sintered. Since the theoretical density of the body was 6.379 g / cm ³ , the filling rate was 24.8%.
The filling rate was determined as shown in the following formula.
Filling rate = 100 × [(tap density) / (theoretical density of sintered body)]
It should be noted that the theoretical density of the sintered body is InGaZnO ₄ (JCPDS card number: JCPDS card) as a crystal phase corresponding to a composition in which the atomic ratio of indium element, gallium element and zinc element is 1: 1: 1. 381104), and the theoretical density described in the JCPDS card was adopted.

Thereafter, capsule HIP treatment was performed in the same manner as in Example 3. As a result, the capsule container burst during capsule HIP treatment, and the mixed powder was scattered in the HIP treatment apparatus, making it impossible to produce an IGZO sintered body. It was.
Since the filling rate of the mixed powder is extremely low at 24.8% and the shrinkage rate of the capsule container is 75.2%, the shrinkage of the capsule container cannot follow the shrinkage of the mixed powder, and the capsule container is ruptured. .

(Comparative Example 2)
<Manufacture of IGZO sintered body>
Indium oxide powder having a tap density of 1.95 g / cm ³ (In ₂ O ₃ , primary particle size: 1 μm, manufactured by Soekawa Rikagaku Co., Ltd.), gallium oxide powder having a tap density of 1.39 g / cm ³ (Ga ₂ O ₃ , manufactured by Yamanaka Hutech Co., Ltd., primary particle size: 1.5 μm, zinc oxide powder having a tap density of 1.02 g / cm ³ (ZnO, manufactured by Hakusui Tech Co., Ltd.) Primary particle size: 1. 5 μm) and a mixed powder in which the atomic ratio of indium element, gallium element and zinc element is 2: 2: 1, and a 2 mmφ zirconia ball and polypropylene carbonate (“QPAC40” manufactured by Empower Materials, Molecular weight: 200,000), ethanol and acetone for dissolving polypropylene carbonate, mixed powder: organic binder (polypropylene carbonate) 97: 3 were mixed such that the proportion of the (weight ratio) to obtain a slurry. The slurry thus prepared was placed in a resin pot and wet mixed by a wet ball mill mixing method. This wet mixing was performed using hard ZrO ₂ balls as balls and mixing time of 18 hours. Next, the slurry after wet mixing was taken out, and the balls were sieved and the solvent was removed by an evaporator to obtain a mixed powder. The tap density of indium oxide powder, gallium oxide powder, and zinc oxide powder is based on JIS K5101, and each powder is filled with vibration while applying vibration to a graduated cylinder of a predetermined size until there is no volume change of each powder. And evaluated.

When the obtained mixed powder was filled in a capsule container similar to that used in Example 1 while vibration was applied until the volume of the mixed powder disappeared, the tap density was 1.51 g / cm ³ , which was sintered. Since the theoretical density of the body was 6.495 g / cm ³ , the filling rate was 23.2%.
The filling rate was determined as shown in the following formula.
Filling rate = 100 × [(tap density) / (theoretical density of sintered body)]
The theoretical density of the sintered body is a crystal phase corresponding to a composition in which the atomic ratio of indium element, gallium element, and zinc element is 2: 2: 1. The JCPDS card has In ₂ Ga ₂ ZnO ₇ ( JCPDS card number: 381097), and the theoretical density described in the JCPDS card was adopted.

Thereafter, capsule HIP treatment was performed in the same manner as in Example 3. As a result, the capsule container burst during capsule HIP treatment, and the mixed powder was scattered in the HIP treatment apparatus, making it impossible to produce an IGZO sintered body. It was.
Since the filling rate of the mixed powder is extremely low as 23.2% and the shrinkage rate of the capsule container is 76.8%, the shrinkage of the capsule container cannot follow the shrinkage of the mixed powder, and the capsule container is ruptured. .

(Comparative Example 3)
<Manufacture of IGZO sintered body>
Indium oxide powder having a tap density of 1.95 g / cm ³ (In ₂ O ₃ , primary particle size: 1 μm, manufactured by Soekawa Richemical Co., Ltd.), gallium oxide powder having a tap density of 1.47 g / cm ³ (Ga ₂ O ₃ , rare metal production Co., Ltd., primary particle size: 3.0 μm, zinc oxide powder with a tap density of 1.02 g / cm ³ (ZnO, produced by Hakusui Tech Co., Ltd.) Primary particle size: 1 .5 μm), a mixed powder obtained by weighing the atomic ratio of indium element, gallium element, and zinc element to 1: 1: 1, and a 2 mmφ zirconia ball and polypropylene carbonate (“QPAC40” manufactured by Empower Materials) , Molecular weight: 200,000), ethanol and acetone for dissolving polypropylene carbonate, mixed powder: organic binder (polypropylene carbonate) = 97: 3 ( They were mixed in a ratio Amount ratio) to obtain a slurry. The slurry thus prepared was placed in a resin pot and wet mixed by a wet ball mill mixing method. This wet mixing was performed using hard ZrO ₂ balls as balls and mixing time of 18 hours. Next, the slurry after wet mixing was taken out, and the balls were sieved and the solvent was removed by an evaporator to obtain a mixed powder. The tap density of indium oxide powder, gallium oxide powder, and zinc oxide powder is based on JIS K5101, and each powder is filled with vibration while applying vibration to a graduated cylinder of a predetermined size until there is no volume change of each powder. And evaluated.

When the obtained mixed powder was filled in a capsule container similar to that used in Example 1 while applying vibration until the volume of the mixed powder disappeared, the tap density was 1.55 g / cm ³ , which was sintered. Since the theoretical density of the body was 6.379 g / cm ³ , the filling factor was 24.2%.
The filling rate was determined as shown in the following formula.
Filling rate = 100 × [(tap density) / (theoretical density of sintered body)]
It should be noted that the theoretical density of the sintered body is InGaZnO ₄ (JCPDS card number: JCPDS card) as a crystal phase corresponding to a composition in which the atomic ratio of indium element, gallium element and zinc element is 1: 1: 1. 381104), and the theoretical density described in the JCPDS card was adopted.

Thereafter, capsule HIP treatment was performed in the same manner as in Example 3. As a result, the capsule container burst during capsule HIP treatment, and the mixed powder was scattered in the HIP treatment apparatus, making it impossible to produce an IGZO sintered body. It was.
The filling rate of the mixed powder is extremely low at 24.2%, and the shrinkage rate of the capsule container is 75.8%. .

(Comparative Example 4)
<Manufacture of IGZO sintered body>
Indium oxide powder having a tap density of 1.95 g / cm ³ (In ₂ O ₃ , primary particle size: 1 μm, manufactured by Soekawa Rikagaku Co., Ltd.), gallium oxide powder having a tap density of 1.48 g / cm ³ (Ga ₂ O ₃ , rare metal production Co., Ltd., primary particle size: 1.0 μm, zinc oxide powder having a tap density of 1.02 g / cm ³ (ZnO, Hakusui Tech Co., Ltd., primary particle size: 1) .5 μm) mixed powder in which the atomic ratio of indium element, gallium element and zinc element was 2: 2: 1, 2 mmφ zirconia balls and polypropylene carbonate (“QPAC40” manufactured by Empower Materials) , Molecular weight: 200,000), ethanol and acetone for dissolving polypropylene carbonate, mixed powder: organic binder (polypropylene carbonate) = 97: 3 ( They were mixed in a ratio Amount ratio) to obtain a slurry. The slurry thus prepared was placed in a resin pot and wet mixed by a wet ball mill mixing method. This wet mixing was performed using hard ZrO ₂ balls as balls and mixing time of 18 hours. Next, the slurry after wet mixing was taken out, and the balls were sieved and the solvent was removed by an evaporator to obtain a mixed powder. The tap density of indium oxide powder, gallium oxide powder, and zinc oxide powder is based on JIS K5101, and each powder is filled with vibration while applying vibration to a graduated cylinder of a predetermined size until there is no volume change of each powder. And evaluated.

When the obtained mixed powder was filled in the same capsule container as used in Example 1 while applying vibration until the volume of the mixed powder disappeared, the tap density was 1.52 g / cm ³ , which was sintered. Since the theoretical density of the body was 6.495 g / cm ³ , the filling rate was 23.4%.
The filling rate was determined as shown in the following formula.
Filling rate = 100 × [(tap density) / (theoretical density of sintered body)]
The theoretical density of the sintered body is a crystal phase corresponding to a composition in which the atomic ratio of indium element, gallium element, and zinc element is 2: 2: 1. The JCPDS card has In ₂ Ga ₂ ZnO ₇ ( JCPDS card number: 381097), and the theoretical density described in the JCPDS card was adopted.

Thereafter, capsule HIP treatment was performed in the same manner as in Example 3. As a result, the capsule container burst during capsule HIP treatment, and the mixed powder was scattered in the HIP treatment apparatus, making it impossible to produce an IGZO sintered body. It was.
Since the filling rate of the mixed powder is extremely low as 23.4% and the shrinkage rate of the capsule container is 76.6%, the shrinkage of the capsule container cannot follow the shrinkage of the mixed powder, and the capsule container is ruptured. .

Claims

Formula: In x Ga y Zn z O a
[Wherein, x / (x + y) = 0.2 to 0.8, z / (x + y + z) = 0.1 to 0.5, a = (3/2) x + (3/2) y + z]
An In—Ga—Zn-based composite oxide sintered body represented by:
An In—Ga—Zn-based composite oxide sintered body having a bulk resistance value of less than 1.0 × 10 −3 Ω · cm.
2. The In—Ga—Zn-based composite oxide according to claim 1, which is a target used for film formation by sputtering, ion plating, pulse laser deposition (PLD), or electron beam (EB) evaporation. A target obtained by processing a sintered body.
A step (a) of pressure-molding a mixed powder containing indium, gallium, zinc, oxygen and satisfying the following mixing conditions and having a primary particle size of 0.6 μm or more to form a molded body;
The step (b) of filling the molded body into the capsule container and subjecting the capsule to hot isostatic pressing so that the filling rate of the mixed powder into the capsule container calculated from the following formula is 50% or more A method for producing an In—Ga—Zn-based composite oxide sintered body.
Mixing conditions: metal atomic ratio In: Ga: Zn = x: y: z, x / (x + y) is 0.2 to 0.8, and z / (x + y + z) is 0.1 to 0.5 Satisfy a relationship.
Filling rate (%) = (packing density of mixed powder into capsule container / theoretical density of sintered body) × 100
4. The method for producing an In—Ga—Zn composite oxide sintered body according to claim 3, wherein in step (a), indium oxide powder, gallium oxide powder and zinc oxide powder are mixed to form a mixed powder.
In the step (a), indium oxide powder, gallium oxide powder and zinc oxide powder are mixed so as to have a metal atomic ratio of In: Ga: Zn = 1: 1: 1 to form a mixed powder. A method for producing the described In—Ga—Zn-based composite oxide sintered body.
6. The production of an In—Ga—Zn-based composite oxide sintered body according to claim 5, wherein in the step (a), the mixed powder is pressure-molded so that the density of the molded body is 3.19 g / cm 3 or more. Method.
In the step (a), indium oxide powder, gallium oxide powder and zinc oxide powder are mixed so as to have a metal atomic ratio of In: Ga: Zn = 2: 2: 1 to form a mixed powder. A method for producing the described In—Ga—Zn-based composite oxide sintered body.
The production of an In-Ga-Zn-based composite oxide sintered body according to claim 7, wherein in the step (a), the mixed powder is pressure-molded so that the density of the molded body is 3.25 g / cm 3 or more. Method.
The method for producing an In-Ga-Zn-based composite oxide sintered body according to any one of claims 3 to 8, wherein in the step (a), the mixed powder contains a binder and is pressure-molded.
In step (b), the molded body is filled into a capsule container, the filling rate of the mixed powder is set to 50% or more, debinding treatment and vacuum degassing treatment of the capsule container are performed at the same time, and then capsule hot isostatic pressing The method for producing an In—Ga—Zn-based composite oxide sintered body according to claim 9, wherein the treatment is performed.
The In-Ga-Zn-based composite oxide firing according to any one of claims 3 to 10, wherein in the step (b), the molded body is subjected to capsule hot isostatic pressing at a sintering temperature of 1000 to 1400 ° C. A method for producing a knot.
The In-Ga-Zn-based composite oxide sintered product according to any one of claims 3 to 11, wherein in the step (b), an inert gas is used as a pressure medium, and the capsule is subjected to capsule hot isostatic pressing. Body manufacturing method.
The In-Ga-Zn-based composite oxide sintered body according to any one of claims 3 to 12, wherein in the step (b), the molded body is subjected to capsule hot isostatic pressing with an applied pressure of 50 MPa or more. Production method.