JPH1072253A - Method for producing high-density ITO sintered body, high-density ITO sintered body, and ITO sputter target using the same - Google Patents

Abstract

(57) Abstract: A method for producing an ITO sputter target, which comprises molding and sintering a powder comprising indium, tin and oxygen, has excellent sputter target characteristics and is industrially useful in sintering density. And a dense ITO sintered body, and an ITO sputter target obtained using the same as a raw material. A method for producing an indium oxide-tin oxide sintered body for molding and sintering a powder composed of indium, tin, and oxygen, wherein the density of the indium oxide-tin oxide powder and the BE
BET specific surface area diameter determined from T specific surface area is 0.05 μm
And a powder having a BET specific surface area of more than 0.05 μm and 1 μm or less of indium oxide and / or tin oxide powder is mixed to form a powder of 1450 ° C. or more and 1650 ° C. A method for producing an indium oxide-tin oxide sintered body sintered in the range of C or less, an indium oxide-tin oxide sintered body produced by the production method, and an ITO sputter target obtained using the same as a raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a high-density indium oxide-tin oxide sintered body.

[0002]

2. Description of the Related Art Indium oxide-tin oxide (Indium oxide)
A thin film is used as a transparent conductive film for a liquid crystal display because it has high conductivity and excellent translucency.

[0003] As a method of forming an ITO thin film, I
Examples include a method of applying a TO powder to a base material, and a method of forming an ITO film on a base material surface by a sputtering method of an ITO sintered body target obtained by molding and sintering an oxide raw material powder. You. The method of applying the ITO powder to the base material is somewhat inferior in film quality and performance as compared with the sputtering method.

In the method of manufacturing an ITO thin film by sputtering using an ITO sintered body target, a blackening phenomenon of the ITO target surface called nodule occurs. Therefore, the sputtering is stopped and the ITO target is taken out. However, there is a problem in that productivity is reduced because an operation called cleaning for scraping the nodules is required. I
The generation of nodules in a sputtering method using a TO sintered body target is likely to occur in a low-density ITO target, and the use of a high-density ITO target suppresses the generation of nodules, thereby eliminating the cleaning step,
Productivity is improved.

[0005] The low-density ITO target has a problem that the resistance increases as sputtering continues and the sputter efficiency decreases. In addition, the low-density ITO target generates dust called particles in the sputtering apparatus. ITO deposited and deposited on a substrate for ITO film
There were also problems such as deteriorating the characteristics of the film and breaking the pattern of the fine ITO film. Furthermore, the low-density ITO target has a high resistance value itself, which results in low spatter productivity. If the supply power is increased during sputtering, abnormal discharge occurs and the sputtering cannot be performed stably. is there.

It has been known to raise the sintering temperature to increase the sintering density and obtain a high-density ITO target. However, when the sintering temperature is increased, the shrinkage during sintering increases.
Warpage and cracking of the sintered body are likely to occur, and the yield of the product is deteriorated. Further, when sintering is performed at a high temperature, the structure of the sintered body becomes coarse and the crystal grain size becomes too large.
There is a problem that the strength of the TO sputter target is reduced, the cracks are easily broken, and the spatter becomes unstable and the quality of the ITO film is deteriorated.

As a method for obtaining a high-density ITO sintered body, a hot pressing method or a hot isostatic pressing (hot is
sintering is performed under pressure to obtain a high-density ITO sintered body. However, in the hot pressing method and the HIP method, the temperature is increased. Therefore, tin oxide could not be dissolved sufficiently, the resistance value of the ITO target did not decrease, and only a non-uniform ITO target was obtained. In addition, when the hot press method or the HIP method is used, expensive equipment is required, so that there is a problem that the price of the product increases.

A method of sintering an ITO sintered body in a pressurized oxygen gas atmosphere without using a hot press method or a HIP method has been devised (JP-A-3-207858). In order to perform sintering in a pressurized oxygen gas atmosphere, a special device that can withstand the pressure is required, and expensive equipment is required. Therefore, there is a problem that the price of the product increases. Further, there is a problem such as safety in a high-pressure oxygen gas atmosphere.

In addition, a method has been proposed in which tin oxide powder having a large particle size is mixed with fine indium oxide powder (Japanese Patent Application Laid-Open No. 6-183732). However, when the particle size is large, diffusion does not sufficiently occur. May be uneven.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for forming and sintering a powder comprising indium, tin and oxygen.
An object of the present invention is to provide a dense ITO sintered body having a high sintering density, which has excellent characteristics as a sputter target and is industrially useful in a method for manufacturing an O sputtering target.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that indium oxide-
When a powder having a converted particle diameter (BET diameter) determined from the density of the tin oxide powder and the BET specific surface area is formed and sintered in a specific temperature range, it is possible to obtain a high-density ITO sintered body. As a result, the present invention has been completed. That is, the present invention provides the following (1) to (7). In a method for producing a sintered body of indium oxide-tin oxide, in which a powder comprising indium, tin and oxygen is molded and sintered,

(1-i) Converted particle diameter (BET diameter) determined from the density of the indium oxide-tin oxide powder and the BET specific surface area
Is more than 0.05 μm and less than 1 μm
A method for producing an indium oxide-tin oxide sintered body, characterized by sintering in the range of 0 ° C or more and 1650 ° C or less.

(1-ii) A method for producing a sintered body of indium oxide-tin oxide, in which a powder comprising indium, tin and oxygen is formed and sintered, the density of indium oxide powder and B
The converted particle diameter (BET diameter) determined from the ET specific surface area is 0.0
The converted particle diameter (BE) determined from the density of the indium oxide powder of more than 5 μm and 1 μm or less and the tin oxide powder and the BET specific surface area
Indium oxide-tin oxide sintered body characterized by mixing and molding tin oxide powder having a T diameter of more than 0.05 μm and not more than 1 μm and sintering in the range of 1450 ° C. to 1650 ° C. Manufacturing method

(1-iii) In a method for producing an indium oxide-tin oxide sintered body in which a powder comprising indium, tin and oxygen is molded and sintered, the powder is obtained from the density of the indium oxide-tin oxide powder and the BET specific surface area. Converted particle size (BET
Indium oxide having a diameter of more than 0.05 μm and 1 μm or less
A tin oxide powder having a converted particle diameter (BET diameter) calculated from the density of the tin oxide powder and the indium tin oxide powder and the BET specific surface area (BET diameter) of more than 0.05 μm and 1 μm or less is mixed and molded.
A method for producing an indium oxide-tin oxide sintered body characterized in that sintering is performed at a temperature of 50 ° C. or more and 1650 ° C. or less.

(1-iv) Converted particle diameter (BET diameter) determined from the density of the indium oxide-tin oxide powder and the BET specific surface area
Indium oxide-tin oxide powder having a particle size exceeding 0.05 μm and 1 μm or less, and indium oxide powder having a converted particle size (BET diameter) determined from the density of the indium oxide powder and the BET specific surface area exceeding 0.05 μm and 1 μm or less. Mix and mold,
A method for producing an indium oxide-tin oxide sintered body, comprising sintering in the range of 1450 ° C or more and 1650 ° C or less.

(2) A mixed aqueous solution of an indium salt and a tin salt is reacted with an alkaline aqueous solution, and the obtained precipitate is calcined to obtain a reduced particle diameter (BET) determined from the density of the indium oxide-tin oxide powder and the BET specific surface area. Powder having a diameter of more than 0.05 μm and 1 μm or less is obtained.
A method for producing an indium oxide-tin oxide sintered body characterized by sintering at a temperature of 1650 ° C. or less.

(3) An aqueous solution of an indium salt and an aqueous solution of a tin salt are each reacted with an alkaline aqueous solution, and each of the resulting precipitates is calcined to obtain a converted particle diameter determined from the density of the indium oxide powder and the BET specific surface area. An indium oxide powder having a (BET diameter) of more than 0.05 μm and 1 μm or less;
A tin oxide powder having a converted particle diameter (BET diameter) calculated from the density of the tin oxide powder and the BET specific surface area of more than 0.05 μm and not more than 1 μm was obtained, and the respective powders were mixed and molded.
A method for producing an indium oxide-tin oxide sintered body characterized by sintering in the range of ゜ C to 1650 ° C.

(4) A mixed aqueous solution of an indium salt and a tin salt and an aqueous solution of a tin salt are respectively reacted with an alkaline aqueous solution, and each of the resulting precipitates is fired to obtain the density of the indium oxide-tin oxide powder and the BET ratio. Indium oxide-tin oxide powder having a converted particle diameter (BET diameter) determined from the surface area of more than 0.05 μm and 1 μm or less, the density of the tin oxide powder and the BET
The converted particle diameter (BET diameter) determined from the specific surface area is 0.05μ
Indium oxide-tin oxide sintered body characterized in that tin oxide powder having a particle size exceeding 1 m and not more than 1 μm is obtained, the respective powders are mixed, molded and sintered in the range of 1450 ° C. to 1650 ° C. Manufacturing method

(5) A mixed aqueous solution of an indium salt and a tin salt and an aqueous solution of an indium salt are reacted with an alkaline aqueous solution, respectively, and each of the resulting precipitates is fired to obtain the density of the indium oxide-tin oxide powder and the BET ratio. Indium oxide-tin oxide powder having a converted particle diameter (BET diameter) determined from the surface area of more than 0.05 μm and 1 μm or less, and a converted particle diameter (BET diameter) determined from the density of the indium oxide powder and the BET specific surface area
Indium oxide powder having a diameter of more than 0.05 μm and 1 μm or less is obtained, and the respective powders are mixed and molded.
A method for producing an indium oxide-tin oxide sintered body characterized by sintering in the range of ゜ C to 1650 ° C.

(6) A method for producing an indium oxide-tin oxide sintered body characterized by being produced by the method of (1) to (5). (7) A method of producing an indium oxide-tin oxide sintered body by the method of (1) to (6). An ITO sputter target obtained by using an indium-tin oxide sintered body as a raw material. Hereinafter, the present invention will be described in detail.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Indium salts used in the present invention include indium chloride, indium nitrate, indium sulfate, indium acetate, indium oxalate, indium fluoride, indium bromide, and the like. Stannic chloride, stannic nitrate, stannic sulfate, stannic acetate, stannic oxalate, stannic fluoride, stannic bromide, stannous chloride, stannous nitrate, stannous sulfate Tin, stannous acetate, stannous oxalate, stannous fluoride, stannous bromide. Further, as the alkaline aqueous solution, ammonia water, ammonium carbonate aqueous solution, urea aqueous solution, sodium hydroxide aqueous solution, water An aqueous solution of potassium oxide, an aqueous solution of rubidium hydroxide, an aqueous solution of barium hydroxide and the like can be given.

Indium oxide used in the present invention
The tin oxide powder, indium oxide powder or tin oxide powder is produced, for example, by the following method. That is, first, an aqueous solution of an indium salt and a tin salt, an aqueous solution of an indium salt and an aqueous solution of a tin salt are reacted with an alkaline aqueous solution to obtain a precipitate containing indium and / or tin, and the obtained precipitate is subjected to solid-liquid separation. I do. The method of solid-liquid separation is not particularly limited, and examples include decantation, centrifugation, and filtration. Examples of the method of filtration include methods such as suction filtration and filter press.

Each of the solid-liquid separated precipitates is fired,
Since indium and / or tin contains salts such as ammonium salts such as ammonium chloride and ammonium nitrate, and alkali metal salts such as sodium chloride and sodium nitrate formed by reacting with an alkaline aqueous solution, they are formed together with the precipitate before firing. Preferably, the precipitate is washed with water or an aqueous solution or solvent that dissolves the salts. Examples of the water or aqueous solution or solvent for dissolving the generated salts used in the present invention include water, aqueous ammonia, alcohols such as methanol and ethanol, and the like. Next, the precipitate containing the washed indium and / or tin is dried. Examples of the drying method include a normal drying method by heating, vacuum drying, freeze drying and the like.

The dried precipitate containing indium and / or tin obtained by the above method is calcined to obtain an indium oxide-tin oxide powder, an indium oxide powder or a tin oxide powder. Each firing temperature is preferably in the range of 600 to 1300 ° C. When the calcination temperature is lower than 600 ° C., crystallization is not sufficient, and decomposition of salts such as ammonium chloride attached to the precipitate containing indium and / or tin is insufficient. When the sintering temperature exceeds 1300 ° C., primary particles are crystal-grown and a part of the particles is aggregated to obtain respective indium oxide-tin oxide powder, indium oxide powder or tin oxide powder having good sinterability. May not be.

The atmosphere gas for each firing is air, oxygen gas, nitrogen gas, hydrogen halide gas, halogen gas,
Or a mixture thereof.Examples of the hydrogen halide gas include hydrogen chloride, hydrogen bromide, hydrogen iodide, and hydrogen fluoride.Examples of the halogen gas include chlorine, bromine, iodine, and fluorine. . It is preferable to calcinate in an atmosphere containing a hydrogen halide gas or a halogen gas, the particle shape is good, the cohesion is weak, and the indium oxide-tin oxide powder, the indium oxide powder, or the tin oxide is excellent in dispersibility. A powder can be obtained.

When firing in an atmosphere containing a hydrogen halide gas or a halogen gas, 1% by volume of the hydrogen halide gas or the halogen gas is used based on the total volume of the atmosphere gas.
Above, preferably 5% by volume, more preferably 10% by volume
It is fired in the atmosphere gas contained above. As a hydrogen halide gas or a diluent gas for the halogen gas, an inert gas such as argon, nitrogen, air, or a mixed gas thereof can be used.

The pressure of the atmosphere gas in each firing is not particularly limited, and can be arbitrarily selected within a range used industrially. The appropriate baking time is not necessarily limited because it depends on the concentration of the atmosphere gas and the baking temperature.
Preferably it is 1 minute or more, more preferably 10 minutes or more. The supply source and supply method of the atmospheric gas are not particularly limited. It is sufficient that the above-mentioned atmospheric gas can be introduced into a reaction system in which a raw material containing indium and / or tin as a raw material exists.

The firing apparatus is not necessarily limited, and a so-called firing furnace can be used. In particular, when a hydrogen halide gas or a halogen gas is used, the firing furnace is preferably made of a material that is not corroded by the hydrogen halide gas or the halogen gas. Further, it is desirable to have a structure capable of adjusting the atmosphere. Further, since a corrosive gas such as a hydrogen halide gas or a halogen gas is used, it is desirable that the firing furnace has airtightness.

From the industrial viewpoint, it is preferable to perform calcination by a continuous method. For example, a tunnel furnace or the like can be used. In the case of firing in a corrosive gas atmosphere, the apparatus, crucible and boat used in the firing step are preferably made of alumina, quartz, acid-resistant brick or graphite.

According to the above-mentioned production method, an indium oxide-tin oxide powder, an indium oxide powder or a tin oxide powder composed of fine primary particles of about 0.5 μm or less can be obtained. However, the aggregate particle diameter of each powder can be obtained as indium oxide-tin oxide powder, indium oxide powder or tin oxide powder. Depending on the conditions for depositing a precipitate containing indium and / or tin, the thickness may be 1 μm or more. For example, a high-density ITO sintered body having a relative density exceeding 90% may not be obtained. Agglomeration between primary particles is weak, and the average agglomeration particle diameter can be easily reduced to 1 μm or less by light pulverization, for example, pulverization using a ball mill or a jet mill. Can be manufactured.

When hydrogen halide or a halogen gas is used as the atmosphere gas during the firing, chlorine remains in the indium oxide-tin oxide powder, indium oxide powder or tin oxide powder after firing. May be
Halogen components may remain, but such halogen components can be removed by washing each powder after calcination with water or re-calcination in air or the like.

In the present invention, the content of tin oxide in the indium oxide-tin oxide sintered body is 1 to 50% by weight, and when used for a normal ITO thin film, 2 to 20% by weight.
The mixing ratio of the indium oxide-tin oxide powder, the indium oxide powder, or the tin oxide powder can be arbitrarily selected so as to be the tin oxide content of the indium oxide-tin oxide sintered body.

Next, ITO powder, ie, indium oxide-tin oxide powder, mixed powder of indium oxide powder and tin oxide powder, mixed powder of indium oxide-tin oxide powder and tin oxide powder, or indium oxide-oxide A mixed powder of tin powder and indium oxide powder is sintered to produce an ITO sintered body. Each of the indium oxide-tin oxide powder, the indium oxide powder and the tin oxide powder has a converted particle diameter (BET diameter) of 0. 0 determined from the BET specific surface area and each powder density.
More than 05μm, 1μm or less, preferably 0.1μm
Use larger (exceeding) 0.5 μm or less. Thereby, the relative density is 90% or more, preferably 95%.
% Or more of a high-density ITO sintered body can be obtained. Each converted particle size (B) determined from the BET specific surface area
When the (ET diameter) is 0.05 μm or less, the agglomeration of the powder becomes large, the compact density does not increase even when the compaction pressure is increased, and the compact density changes from a low compact density to a high density by sintering. Cracks in the sintered body,
In some cases, the sintered body cracks. Especially when trying to obtain a large sintered body, the degree of shrinkage is large,
The sintered body is easily broken. Furthermore, if the agglomeration of the powder is large,
When molding by axial pressure molding, pressure is hardly applied to the whole, and the molded body is cracked in layers. In addition, the powder of the molded body is hardly uniform, and the sintered body is likely to warp during sintering.

If the converted particle diameter (BET diameter) determined from the BET specific surface area exceeds 5 μm, sintering occurs with the driving force of the surface energy of the raw material powder particles, so that a sufficient driving force for sintering cannot be obtained. In addition, sintering does not sufficiently occur, and a high-density sintered body cannot be obtained. In order to obtain a high-density sintered body, it is preferable to use a powder of 0.5 μm or less.

Next, each of the above-mentioned powders is molded, given a specific shape such as a plate shape or a disk shape, and then sintered. The molding method is not particularly limited, and is uniaxial pressure molding, cold isostatic pressing, or cold isostatic pressing.
CIP), slip casting (slurry casting) molding, filter press molding, extrusion molding, injection molding, and the like. The above molding method may be used alone,
Alternatively, the above molding methods may be used in combination.

The sintering temperature is preferably in the range of 1450 ° C. to 1650 ° C. If the sintering temperature is lower than 1450 ° C., the sintering density is not sufficiently increased, the solid solution of tin oxide in indium oxide is not sufficient, and the resistance value is not reduced.

If the sintering temperature exceeds 1650 ° C., there is a problem that crystal grains are likely to grow and the strength of the ITO sputter target is lowered. If the temperature is high, ITO
A special material having a high melting point and low reactivity with ITO must be selected as a material for placing the molded body. An electric furnace that can be sintered at a high temperature has a special structure, which increases the cost of the electric furnace. Further, when sintering at a high temperature, the electric furnace is severely damaged, and the running cost of operating the electric furnace also increases.

The sintering is preferably performed in an atmosphere containing 1 atm of oxygen gas. If sintering is performed at a high temperature in an atmosphere containing no oxygen gas, for example, a nitrogen gas or an argon gas atmosphere, it is a reducing atmosphere for ITO, and dissociation of the oxide into metal and oxygen gas occurs. The sintering is preferably performed in an atmosphere containing oxygen gas, such as in air at 1 atm. More preferably, oxygen gas is 100%
In an oxygen gas atmosphere. A method of sintering in a pressurized oxygen gas atmosphere in which the pressure is greater than 1 atm has also been proposed, but in order to perform sintering in a pressurized oxygen gas atmosphere, a special sintering furnace or apparatus capable of withstanding the pressurization is required. Need and cost is high. Also, a high-temperature pressurized oxygen gas atmosphere has a problem of safety and the like.

According to the method for producing an ITO sintered body of the present invention, the relative density of the sintered body is 90% or more, preferably 95%
The above-described high-density ITO sintered body is obtained, and the sintering is preferably performed, for example, in an atmosphere containing normal-pressure oxygen gas such as air, and more preferably in pure oxygen. Perform in an atmosphere. The pure oxygen atmosphere means an atmosphere containing an oxygen gas and an unavoidable impurity gas. When sintering is performed in air or in an atmosphere containing oxygen gas, a high-density ITO sintered body of 97% or more and 98.5% or more in oxygen can be obtained. When the sintered body of the present invention is used as a sputtering target, reduction of nodules, improvement of sputtering efficiency, reduction of particles,
It can be expected that abnormal discharge is reduced and the quality of the formed ITO film is improved.

A transparent conductive film for a liquid crystal display (LCD) or the like is manufactured by a method of manufacturing a normal ITO target such as grinding and polishing the ITO sintered body of the present invention and bonding it to a copper backing plate with indium solder. A sputter target for fabrication is obtained.

[0041]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Various measurements in the present invention were performed as follows. 1. Measurement of BET Specific Surface Area of ITO Powder Used for Sintering The BET specific surface area was measured using Flowsorb II, Model 2300 (manufactured by Micromeritics).

Also, the BET specific surface area diameter (D
BET) was calculated. DBET (μm) = 6 / (S * ρ) S = BET specific surface area (m ² / g) ρ = density of ITO powder (g / cm ³ ) Powder density for obtaining BET specific surface area diameter (DBET) is as follows. It was 7.16 g / cm ^{3 according} to the following equation. Density of indium oxide 7.18 g / cm ³ and density of tin oxide 6.95
It was calculated from the following formula based on g / cm ³ and tin oxide content of 10 wt%.

2. Measurement of Density of ITO Sintered Body After Sintering The bulk density of the ITO sintered body is determined according to JIS Z8807-1.
It was determined by the Archimedes method (buoyancy method) according to the measuring method of 976 and JISR 2205-1992. As a true density for obtaining a relative density, a powder density of 7.16 g / cm ³ used at a BET specific surface area diameter (DBET) was used.

Example 1 A weight ratio calculated as an oxide [SnO ₂ / (In ₂ O ₃ +
[SnO ₂ )] was added dropwise to a mixed aqueous solution of indium chloride and tin chloride at a concentration of 10%, and 25% aqueous ammonia was added dropwise. The precipitate was reacted and solid-liquid separated. Baked at 1200 ° C. for 30 minutes while flowing a 20% by volume hydrogen chloride gas diluted with air from 1000 ° C., and then washed with water.
A powder was obtained. The obtained ITO powder had a BET specific surface area of 3.7 m ² / g and a BET specific surface area diameter of 0.23 μm.

After the ITO powder was uniaxially pressed at 100 kg / cm ² , CIP was applied at a pressure of 3 ton / cm ² .
Pressurization was performed. The obtained compact was placed in an electric furnace, and the pressure in the electric furnace was reduced to 0.2 torr by a vacuum pump, and the atmosphere was replaced with an oxygen gas atmosphere. After reaching normal pressure, sintering was performed while flowing oxygen gas at a flow rate of 2 l / min. Sintering was performed for 10 hours in an oxygen gas atmosphere at 1600 ° C. and a normal pressure at a heating rate of 10 ° C./min to obtain an ITO sintered body. The obtained sintered body was densified to a sintered body density of 7.10 g / cm ³ and a relative density of 99.1%.

Example 2 An ITO molded body obtained by the same method as in Example 1 was placed in an electric furnace and sintered in the same manner as in Example 1 except that the sintering atmosphere was changed from oxygen to air. I let it. The obtained sintered body had a sintered body density of 6.98 g / cm ³ and a relative density of 9
Densified to 7.5%.

Comparative Example 1 An ITO molded body obtained in the same manner as in Example 1 was placed in an electric furnace, and the sintering temperature was changed to 1400 ° C.
Sintering was performed in the same manner as described above. The obtained sintered body had a sintered body density of 6.17 g / cm ³ and a relative density of only 86.2%.

Comparative Example 2 A commercially available ITO powder having a BET specific surface area of 0.1 m ² / g and a BET specific surface area diameter of 8.4 μm was prepared at 1000 kg /
After uniaxial press molding at cm ^2, and subjected to CIP pressing at a pressure of 3 ton / cm ^2. Example 1
Sintering was performed in the same manner as described above. The resulting sintered body had a sintered body density of 4.86 g / cm ³ and a relative density of only 67.8%.

Example 3 57.40 g of metal indium (99.99% purity) was added to 6
Dissolve in normal hydrochloric acid aqueous solution and dilute with ion exchange water
200 ml of an indium salt aqueous solution prepared as L and 6.21 g of metallic tin (purity: 99.99%) dissolved in a concentrated hydrochloric acid aqueous solution to obtain 100 ml of a tin salt aqueous solution, and 21 ml were collected and mixed. 221 ml of a mixed aqueous solution of
Was adjusted. The indium and tin concentrations in the mixed aqueous solution of the indium salt and the tin salt were respectively In = 51.95 g /
1 and Sn = 5.91 g / l. In a mixed aqueous solution of the indium salt and the tin salt and 12.5% ammonia water,
While stirring 400 ml of ion-exchanged water adjusted to pH = 4.5 and keeping it at 1 ° C. in a 1 L beaker maintained at 60 ° C., simultaneously maintain the pH during the reaction at 4.5 while taking 35 minutes. Supplied. For 2 minutes from the start of the reaction, pH = 3.0 to 3.0
Variations in the range of 5.2 were seen, after which pH =
The reaction was maintained at a range of 4.4 to 4.6 to produce a precipitate containing indium and tin. After the reaction is completed,
After stirring for 0 minutes, the mixture was left standing at 60 ° C. for 6 hours, and further left still at room temperature for 14 hours to mature the precipitate. The sedimentation volume of the sediment after aging is 3.5 c / g of theoretically obtained ITO.
c. Next, suction filtration (Buchner type funnel with an inner diameter of about 76 mm (manufactured by Nikkato Co., Ltd., filtration filter and Buchner type)), quantitative filter paper (manufactured by Advantech Toyo, quantitative filter paper N
o. 5C), aspirator (HAN, manufactured by Yamato Scientific Co., Ltd.)
DY ASPIRATOR)), collect the precipitate,
Washing was performed 10 times with about 120 ml of ion-exchanged water. The time required for filtration and washing is 1 hour, excellent in filterability,
The operation was very easy. In addition, this precipitate is kept at 110 ° C.
The dried product was easily crushed. Next, the dried product was filled in an alumina boat. The firing was performed in a tubular furnace (MS electric furnace, manufactured by Motoyama Co., Ltd.) using a quartz furnace core tube (diameter 58 mm, length 1200 mm). The heating rate is 10 ° C./min up to 900 ° C., 1100
Up to 5 ° C / min. As the atmosphere gas, only air is allowed to flow from room temperature to 1000 ° C., and from 1000 ° C. to 2 ° C.
While flowing 0% by volume of hydrogen chloride gas (air dilution), 1
After baking at 100 ° C. for 30 minutes, the mixture was cooled by flowing only air, washed with water and dried to obtain ITO powder. Hydrogen chloride gas was a cylinder hydrogen chloride (purity 99.9) manufactured by Tsurumi Soda Co., Ltd.
%). The obtained ITO powder had a tin oxide content of 9.9% by weight, a BET specific surface area of 8.2 m ² / g and a B
ET specific surface area diameter 0.10μm, 50% of cumulative particle size distribution
The diameter was 0.33 μm. Further, the ITO powder was subjected to a scanning electron microscope (JSM-T220 manufactured by JEOL Ltd.).
Observation by a mold) revealed that the ITO powder had a primary particle diameter of about 0.1 μm and weak aggregation of the primary particles. The obtained ITO powder was formed into a disk having a diameter of 10 mm,
As a result of sintering at 0 ° C. for 10 hours, the sintered body density was 7.09 g.
/ Cm ³ , an ITO sintered body densified to 99.1% of the relative density was obtained.

Example 4 The tin oxide content obtained in Example 3 was 9.9% by weight, B
As a result of molding an ITO powder having an ET specific surface area diameter of 0.1 μm and a 50% diameter of a cumulative particle size distribution of 0.33 μm into a disk having a diameter of 10 mm and sintering at 1500 ° C. for 10 hours, a sintered body was obtained. With a density of 7.06 g / cm ³ and a relative density of 98.5
% Was obtained.

Example 5 57.40 g of metal indium was dissolved in a concentrated hydrochloric acid aqueous solution to make 120 mL, and 106 ml of an indium salt aqueous solution was dissolved.
And 5.81 g of metal tin dissolved in a concentrated hydrochloric acid aqueous solution to obtain 93
90 ml from the aqueous tin salt solution was mixed and mixed.
196 ml of a mixed aqueous solution of an indium salt and a tin salt was prepared. The indium and tin concentrations in the mixed aqueous solution of the indium salt and the tin salt are In = 258.69 g / l and Sn = 28.68 g / l, respectively. The mixed aqueous solution of the indium salt and the tin salt and 12.5% ammonia water were adjusted to pH
= 400 ml of ion exchange water adjusted to 4.5
While stirring in a 1 L beaker maintained at 0 ° C., the mixture was fed simultaneously over 69 minutes so as to maintain the pH during the reaction at 4.5. For 2 minutes from the start of the reaction, pH = 3.1-5.
4, but thereafter pH = 4.4.
The reaction was maintained at a range of ~ 4.6 to produce a precipitate containing indium and tin. After the completion of the reaction, the mixture was stirred at 60 ° C. for 30 minutes, left at 60 ° C. for 6 hours, and further stirred at room temperature for 14 hours.
The precipitate was aged by allowing to stand for a period of time. The sedimentation volume of the precipitate after aging was 1.3 cc / g of theoretically obtained ITO. Next, the precipitate was collected by suction filtration (Buchner-type funnel having an inner diameter of 135 mm, quantitative filter paper No. 5C, using an aspirator), and washed 10 times with about 120 ml of ion-exchanged water. The time required for filtration and washing is 1 hour,
The filterability was excellent, and the operation was very easy. When this precipitate was dried at 110 ° C., the dried product could be easily broken. Next, the dried product was filled in an alumina boat. Firing is performed using a quartz furnace core tube (diameter 58 mm, length 12
00 mm) (MS manufactured by Motoyama Corporation, MS)
(Electric furnace). The heating rate is 10 ° C / 900 ° C.
Min., Up to 1100 ° C., at 5 ° C./min. As atmosphere gas, only air is allowed to flow from room temperature to 1000 ° C.
After baking at 1100 ° C. for 30 minutes while flowing hydrogen chloride gas (diluted with air) from 00 ° C. to 20% by volume, the mixture was cooled by flowing only air, washed with water and dried to obtain ITO powder.
As the hydrogen chloride gas, a cylinder hydrogen chloride (purity: 99.9%) manufactured by Tsurumi Soda Co., Ltd. was used. The obtained ITO powder is
5. A tin oxide content of 10.5% by weight and a BET specific surface area of 6.
At 1 m ² / g, the BET specific surface area diameter was 0.14 μm, and the 50% diameter of the cumulative particle size distribution was 1.1 μm. When the ITO powder was observed with a scanning electron microscope, the primary particle diameter was about 0.1 μm. The powder was a powder having weak primary particles. By subjecting the powder to dry crushing, B
The ET specific surface area is 8.7 m ² / g, the BET specific surface area diameter is 0.10 μm, and the 50% diameter of the cumulative particle size distribution is 0.39 μm.
Of ITO powder. The obtained crushed ITO powder was formed into a disk having a diameter of 10 mm and sintered at 1600 ° C. for 10 hours. As a result, the sintered body density was 7.06 g / cm ^3.
Thus, an ITO sintered body densified to 98.6% of the relative density was obtained.

Example 6 An indium salt aqueous solution prepared by dissolving 252.60 g of metal indium in a concentrated hydrochloric acid aqueous solution to make 680 mL, and metal tin 5
3.95 g was dissolved in a concentrated hydrochloric acid aqueous solution, and 117 ml was collected from a 230 ml tin salt aqueous solution. After mixing and mixing, 63 ml of concentrated ammonia water was added to prepare 860 ml of a mixed aqueous solution of an indium salt and a tin salt. The indium and tin concentrations in the mixed aqueous solution of the indium salt and the tin salt were In =
293.72 g / l and Sn = 31.91 g / l. 12.5% in the mixed aqueous solution of the indium salt and the tin salt
A 5 L beaker containing 2000 ml of ion-exchanged water adjusted to pH = 5.0 with ammonia water and maintained at 60 ° C.
While stirring, so as to maintain the pH at 5.0,
The feed was simultaneous over 84 minutes. During the reaction, the pH fluctuated in the range of pH = 3.6 to 5.5 for 2 minutes from the start of the reaction, but was maintained in the range of pH = 4.8 to 5.2 thereafter. To form a precipitate containing indium and tin. After completion of the reaction, after stirring at 60 ° C. for 30 minutes,
The mixture was allowed to stand at 60 ° C. for 6 hours and then at room temperature for 14 hours to mature the precipitate. The sedimentation volume of the precipitate after aging was 1.1 cc / g of theoretically obtained ITO. Next, while the suspension containing the precipitate after aging was stirred again, concentrated aqueous ammonia was added to adjust the pH to 8.5, and then
The precipitate was collected by suction filtration (Buchner-type funnel with an inner diameter of 195 mm, quantitative filter paper No. 5C, using an aspirator), and ammonia water was added to ion-exchanged water to obtain a pH of 10
Washed 5 times with about 2 L of aqueous ammonia adjusted to. The time required for filtration and washing was 25 minutes, the filterability was excellent, and the operation was very easy. In addition, this precipitate
When dried at 0 ° C., the dried product could be easily crushed.
Next, the dried product was filled in a quartz boat. The filling amount was 360 g, and the filling depth was about 10 mm. The firing was performed in a high-temperature box-type electric furnace (manufactured by Morisawa Riko Co., Ltd.) into which a quartz furnace core tube (diameter 160 mm, length 1600 mm) was inserted. The heating rate was 5 ° C./min up to 1100 ° C.
As the atmosphere gas, only air is flowed from room temperature to 1000 ° C., and calcined at 1100 ° C. for 40 minutes while flowing hydrogen chloride gas (diluted with air) from 1000 ° C. to 20% by volume. , Washed with water, dried and I
TO powder was obtained. As the hydrogen chloride gas, a cylinder hydrogen chloride (purity: 99.9%) manufactured by Tsurumi Soda Co., Ltd. was used. The obtained ITO powder has a BET specific surface area of 3.3 m ² / g and a BE
T specific surface area diameter 0.25μm, 50% of cumulative particle size distribution
When the diameter was 2.6 μm and the ITO powder was observed with a scanning electron microscope, the primary particle diameter was about 0.1 to 0.2 μm.
It was a powder in which aggregation of the primary particles was weak. In addition, the powder was subjected to wet pulverization to give an ITO powder having a BET specific surface area of 5.1 m ² / g, a BET specific surface area of 0.16 μm, and a 50% diameter of the cumulative particle size distribution of 0.48 μm. . Further, the chlorine content of the ITO powder was 0.05% or less. The obtained crushed ITO powder was crushed to a diameter of 9%.
As a result of forming into a 0 mm disk shape and sintering at 1600 ° C. for 10 hours, an ITO sintered body having a sintered body density of 7.15 g / cm ³ and a density of 99.8% of the relative density was obtained. Obtained.

Example 7 2000 ml of ion-exchanged water adjusted to pH = 5.0 was placed in a 5 L beaker and kept at 50 ° C. The stirring was carried out while stirring the 50 ° C. ion-exchanged water. The same mixed aqueous solution of indium salt and tin salt as in Example 6 and 12.5% aqueous ammonia were mixed with each other so that the pH during the reaction was maintained at 5.0.
An ITO powder was obtained in the same manner as in Example 6, except that the powder was simultaneously supplied over 1 minute. As for the pH fluctuation during the reaction, a fluctuation in the range of pH = 3.6 to 6.5 was observed for 2 minutes from the start of the reaction, but thereafter, the pH was maintained in the range of 4.8 to 5.3. To form a precipitate containing indium and tin. After completion of the reaction, the mixture was stirred at 60 ° C for 30 minutes, and then stirred at 60 ° C.
For 6 hours, and further left at room temperature for 14 hours to mature the precipitate. The sedimentation volume of the precipitate after aging was 1.7 cc / g of theoretically obtained ITO. Next, while the suspension containing the precipitate after aging was stirred again, concentrated ammonia water was added to adjust the pH to 8.6, followed by suction filtration (Buchner type funnel having an inner diameter of 195 mm, quantitative filter paper No. 1).
The precipitate was collected with 5C, using an aspirator), and washed five times with about 2 L of aqueous ammonia adjusted to pH = 10 by adding aqueous ammonia to ion-exchanged water. The time required for filtration and washing was 30 minutes, the filterability was excellent, and the operation was very easy. When this precipitate was dried at 110 ° C., the dried product could be easily broken. Next, the dried product was fired by the firing method of Example 5, washed with water and dried to obtain an ITO powder having a BET specific surface area of 3.2 m ^2.
/ G, the BET specific surface area diameter was 0.26 μm, the 50% diameter of the cumulative particle size distribution was 2.8 μm, and the ITO powder was observed with a scanning electron microscope.
The powder was 2 μm in which the primary particles were weakly aggregated. In addition, by subjecting the ITO powder to a wet crushing treatment,
The ET specific surface area is 5.1 m ² / g, the BET specific surface area diameter is 0.16 μm, and the 50% diameter of the cumulative particle size distribution is 0.52 μm.
Of ITO powder. The obtained crushed ITO powder was formed into a disc having a diameter of 20 mm, and sintered at 1600 ° C. for 10 hours. As a result, the sintered body density was 7.15 g / cm ^3.
Thus, an ITO sintered body densified to 99.8% of the relative density was obtained.

Comparative Example 3 The tin oxide content obtained in Example 4 was 10.5% by weight, BE
T specific surface area is 6.1m ^Two/ G and the BET specific surface area diameter is 0.
14 μm, 50% diameter of the cumulative particle size distribution is 1.1 μm,
10 mm diameter ITO powder that has not been subjected to dry crushing
And sintered at 1600 ° C for 10 hours
As a result, the sintered body density was 6.34 g / cm.^ThreeAnd the relative density of 8
It densified only to 8.5%.

Comparative Example 4 The precipitate obtained in the same manner as in Example 7 was filtered by suction and washed three times with about 2 l of a 2% by weight aqueous solution of ammonium chloride.
The time required for filtration and washing was 23 minutes, the filterability was excellent, and the operation was very easy. In addition, this precipitate
When dried at 10 ° C., the dried product could be easily crushed. Next, the dried product to which ammonium chloride was adhered was calcined at 1100 ° C. for 30 minutes by flowing the hydrogen chloride gas (diluted with air) at 1000 ° C. to 20% by the calcining method of Example 3, and then washed with water. Drying gave an ITO powder. The obtained ITO powder has a BET specific surface area of 3.8 m.
² / g, the BET specific surface area was 0.22 μm, the 50% diameter of the cumulative particle size distribution was 1.2 μm, and the ITO powder was observed with a scanning electron microscope.
It was an ITO powder with a primary particle size of 0.2 μm and weak aggregation of primary particles. Next, the ITO powder was subjected to dry pulverization treatment to have a BET specific surface area of 7.4 m ² / g, a BET specific surface area of 0.11 μm, and a 50% diameter of the cumulative particle size distribution of 0.1%.
It became 43 μm ITO powder. Further, the chlorine content of the ITO powder was 0.28%. The dry crushed ITO powder was formed into a disc having a diameter of 20 mm,
As a result of sintering at 00 ° C. for 10 hours, the sintered body density was 6.06.
At g / cm ³ , densification was only up to 84.7% of the relative density. The above results are summarized in Table 1 below.

[0057]

Table 1 BET diameter (μm) Temperature Atmosphere Sintered body density Relative density Example 1 0.23 1600 ° C In oxygen 7.10 99.1 Example 2 0.23 1600 ° C In air 6.98 97. 5 Comparative Example 1 0.23 1400 ° C in oxygen 6.17 86.2 Comparative Example 2 8.4 1600 ° C In oxygen 4.86 67.8 Example 3 0.10 1600 ° C in oxygen 7.09999 0.1 Example 4 0.10 1500 ° C in oxygen 7.06 98.5 Example 5 0.10 1600 ° C in oxygen 7.06 98.6 Example 6 0.16 1600 ° C in oxygen 7.15 99.8 Example 7 0.16 1600 ° C in oxygen 7.15 99.8 Comparative Example 3 0.14 1600 ° C in oxygen 6.34 88.5 Comparative Example 4 0.11 1600 ° C in oxygen 6. 06 84.7

[0058]

According to the method for manufacturing an ITO sintered body of the present invention, a dense ITO sintered body having a high sintering density can be easily obtained, and the high-density ITO sintered body obtained by the method of the present invention can be obtained. Has excellent properties as an ITO sputter target,
It is industrially useful.

Claims (17)

[Claims] 1. A method for producing a sintered body of indium oxide-tin oxide, which comprises molding and sintering a powder composed of indium, tin and oxygen.
The converted particle diameter (BET diameter) determined from the T specific surface area is 0.05
A method for producing a sintered body of indium oxide-tin oxide, characterized in that powder having a size of more than 1 μm and less than 1 μm is formed and sintered in a range of 1450 ° C. or more and 1650 ° C. or less. 2. A method for producing a sintered body of indium oxide-tin oxide, which comprises molding and sintering a powder comprising indium, tin and oxygen, wherein a converted particle diameter (BET) determined from the density of the indium oxide powder and the BET specific surface area is used. Indium oxide powder having a diameter of more than 0.05 μm and not more than 1 μm, and tin oxide powder having a converted particle diameter (BET diameter) of more than 0.05 μm and not more than 1 μm obtained from the density of the tin oxide powder and the BET specific surface area. A method for producing an indium oxide-tin oxide sintered body, characterized in that the indium oxide-tin oxide sintered body is sintered at a temperature of 1450 ° C. or more and 1650 ° C. or less. 3. A method for producing an indium oxide-tin oxide sintered body, which comprises molding and sintering a powder comprising indium, tin and oxygen, wherein the density of the indium oxide-tin oxide powder and the BE
The converted particle diameter (BET diameter) determined from the T specific surface area is 0.05
A mixture of indium oxide-tin oxide powder having a particle size of more than 1 μm and less than 1 μm, and tin oxide powder having a converted particle size (BET diameter) obtained from the density of the tin oxide powder and the BET specific surface area of more than 0.05 μm and not more than 1 μm. Molded, 1450 ° C or more, 1650
A method for producing an indium oxide-tin oxide sintered body, characterized by sintering in a range of ゜ C or less. 4. A method for producing an indium oxide-tin oxide sintered body, which comprises molding and sintering a powder comprising indium, tin and oxygen, wherein the density of the indium oxide-tin oxide powder and the BE
The converted particle diameter (BET diameter) determined from the T specific surface area is 0.05
an indium oxide-tin oxide powder having a particle size of more than 1 μm and not more than 1 μm, and a converted particle size (BET diameter) obtained from the density of the indium oxide powder and the BET specific surface area of more than 0.05 μm and 1 μm
The following indium oxide powder was mixed and molded to form 145.
A method for producing a sintered body of indium oxide-tin oxide, characterized by sintering in the range of 0 ° C to 1650 ° C. 5. A mixed aqueous solution of an indium salt and a tin salt is reacted with an alkaline aqueous solution, and the obtained precipitate is calcined to obtain a reduced particle diameter (BET diameter) determined from the density of the indium oxide-tin oxide powder and the BET specific surface area. ) Exceeds 0.05 μm and 1 μm
The following powder was obtained, and the powder was molded.
A method for producing an indium oxide-tin oxide sintered body, comprising sintering at a temperature of 50 ° C. or less. 6. An aqueous solution of an indium salt and an aqueous solution of a tin salt,
Each of the precipitates was reacted with an alkaline aqueous solution, and the resulting precipitates were calcined to obtain the density of the indium oxide powder and BE.
The converted particle diameter (BET diameter) determined from the T specific surface area is 0.05
The converted particle diameter (BE) obtained from the density and the BET specific surface area of the indium oxide powder having a particle size exceeding 1 μm and 1 μm or less and the tin oxide powder.
A tin oxide powder having a T diameter of more than 0.05 μm and not more than 1 μm, mixing and molding the respective powders, and sintering in the range of 1450 ° C. or more and 1650 ° C. or less. -A method for producing a tin oxide sintered body. 7. A mixed aqueous solution of an indium salt and a tin salt and an aqueous solution of a tin salt are respectively reacted with an alkaline aqueous solution, and each of the resulting precipitates is calcined to obtain the density of the indium oxide-tin oxide powder and the BET specific surface area. Particle size (B
An indium oxide-tin oxide powder having an ET diameter of more than 0.05 μm and 1 μm or less; and a tin oxide having a converted particle diameter (BET diameter) of more than 0.05 μm and 1 μm or less obtained from the density of the tin oxide powder and the BET specific surface area. A method for producing an indium oxide-tin oxide sintered body, characterized in that powders are obtained, the respective powders are mixed, molded, and sintered in a range of 1450 ° C to 1650 ° C. 8. A mixed aqueous solution of an indium salt and a tin salt and an aqueous solution of an indium salt are respectively reacted with an alkaline aqueous solution, and each of the resulting precipitates is calcined to obtain the density of the indium oxide-tin oxide powder and the BET specific surface area. Indium oxide-tin oxide powder having a converted particle diameter (BET diameter) of more than 0.05 μm and 1 μm or less, and a converted particle diameter (BET diameter) determined from the density of the indium oxide powder and the BET specific surface area of 0.05 μm And an indium oxide powder having a particle size of not more than 1 μm and obtained by mixing and molding the respective powders and sintering in a range of 1450 ° C. or more and 1650 ° C. or less. Production method. 9. The process according to claim 5, wherein before the calcination of the precipitate, the precipitate is washed with water, an aqueous solution or a solvent in which salts formed with the precipitate are dissolved. 10. The density of indium oxide-tin oxide powder and B
The converted particle diameter (BET diameter) obtained from the ET specific surface area is 0.1
The method according to claim 1 or 5, wherein the powder is a powder having a particle size exceeding 0.5 µm. 11. An indium oxide powder having a converted particle diameter (BET diameter) determined from the density of the indium oxide powder and the BET specific surface area of more than 0.1 μm and not more than 0.5 μm;
7. The method according to claim 2, wherein a tin oxide powder having a converted particle diameter (BET diameter) determined from the density of the tin oxide powder and the BET specific surface area of more than 0.1 μm and not more than 0.5 μm is mixed. 12. The density of indium oxide-tin oxide powder and B
The converted particle diameter (BET diameter) obtained from the ET specific surface area is 0.1
indium oxide-tin oxide powder having a particle diameter of more than 0.5 μm and less than 0.5 μm, and tin oxide powder having a converted particle diameter (BET diameter) calculated from the density of the tin oxide powder and the BET specific surface area of more than 0.1 μm and not more than 0.5 μm The production method according to claim 3 or 7, wherein is mixed. 13. The density of indium oxide-tin oxide powder and B
The converted particle diameter (BET diameter) obtained from the ET specific surface area is 0.1
The indium oxide-tin oxide powder having a particle size of more than 0.5 μm and less than 0.5 μm, and the converted particle size (BET diameter) obtained from the density and the BET specific surface area of the indium oxide powder is more than 0.1 μm and 0.1 μm.
5. A mixture with an indium oxide powder having a size of 5 μm or less.
Or the manufacturing method of 8. 14. The calcination of the precipitate is carried out in an atmosphere containing 1% by volume or more of hydrogen halide gas or halogen gas.
10. The production method according to any one of claims 9 to 9. 15. The method according to claim 1, wherein the sintering is performed in an atmosphere containing oxygen gas. 16. An indium oxide-tin oxide sintered body produced by the method according to claim 1. Description: 17. An ITO sputter target obtained by using an indium oxide-tin oxide sintered body produced by the method according to claim 1 as a raw material.