WO2023127195A1

WO2023127195A1 - Oxide sintered body, method for producing same, and sputtering target material

Info

Publication number: WO2023127195A1
Application number: PCT/JP2022/031765
Authority: WO
Inventors: 耕暉三浦
Original assignee: 三井金属鉱業株式会社
Priority date: 2021-12-28
Filing date: 2022-08-23
Publication date: 2023-07-06
Also published as: TWI814561B; TW202325683A

Abstract

Provided is an oxide sintered body comprising an indium (In) element, a tin (Sn) element, and a silicon (Si) element, with the balance consisting of indium, oxygen and inevitable impurities, wherein the Sn content is 50 mass% to 70 mass% in terms of SnO₂, the Si content is 3 mass% to 15 mass% in terms of SiO₂, and the area percentage of the SiO₂ phase observed in the cross section of the oxide sintered body is at most 3%. A sputtering target material is formed by using said oxide sintered body.

Description

Oxide sintered body, manufacturing method thereof, and sputtering target material

The present invention relates to an oxide sintered body and a method for producing the same. The present invention also relates to a sputtering target material.

A composite oxide containing indium and tin (hereinafter also referred to as “ITO”) is widely used as a material for transparent conductive films. For example, a transparent conductive film with low resistance (resistivity of about 2×10 ⁻⁴ Ωcm) is selected for use in flat panel displays (hereinafter also referred to as “FPD”). On the other hand, a transparent conductive film for a resistive touch panel that is attached to an FPD or the like is required to have high resistance (sheet resistance of about 700Ω to 1000Ω) as a required characteristic in principle.

Therefore, the present applicant previously proposed a sputtering target material that has a low specific resistance that allows DC sputtering and that allows formation of a transparent conductive film with a high film specific resistance (see Patent Document 1). This target material is composed of a composite oxide containing silicon in addition to indium and tin.

International Publication No. 2018/211792

By the way, one of the phenomena raised as a problem when forming a thin film by sputtering is abnormal discharge that occurs during sputtering. Although this phenomenon does not pose a problem if the target material described in Patent Document 1 is used, there is a demand for further reduction of this phenomenon from the viewpoint of improving the productivity of thin films.

Therefore, an object of the present invention is to provide a sputtering target material in which the occurrence of abnormal discharge is further suppressed as compared with the above-described conventional technology. Another object of the present invention is to provide an oxide sintered body suitable for such a target material and a method for producing the same.

The present invention provides an oxide sintered body containing indium (In) element, tin (Sn) element and silicon (Si) element, wherein the Sn content is 50% by mass or more and 70% by mass or less in terms of SnO ₂ There is, the Si content is 3% by mass or more and 15% by mass or less in terms of SiO ₂ , the balance is indium, oxygen and inevitable impurities, and the area ratio of the SiO ₂ phase observed in the cross section of the oxide sintered body is 3% or less.

The present invention also provides a sputtering target material comprising the above oxide sintered body.

Further, in the present invention, a raw material composition containing an indium (In) element source, a tin (Sn) element source and a silicon (Si) element source is prepared, the raw material composition is molded to obtain a molded body, and the molded body A method for producing an oxide sintered body, wherein the compact is sintered at 1450 ° C. or higher and 1500 ° C. or lower for 4 hours or more and 20 hours or less. It provides

FIG. 1 is a schematic diagram showing measurement positions of bulk resistance of sputtering target materials obtained in Examples and Comparative Examples.

The oxide sintered body of the present invention and the sputtering target material using the same contain indium (In) element, tin (Sn) element and silicon (Si) element. These elements form oxides alone, or form composite oxides with two or more elements.

In the oxide sintered body of the present invention and the sputtering target material using the same, the Sn content ratio is 50% by mass or more and 70% by mass or less, preferably 52% by mass or more and 68% by mass or less in terms of SnO ₂ . more preferably 55% by mass or more and 65% by mass or less, and still more preferably 57% by mass or more and 63% by mass or less.
By setting the content ratio of Sn to 50% by mass or more, the film specific resistance of the transparent conductive film obtained by sputtering the oxide sintered body and the sputtering target material using the same can be increased. It can be used as a transparent conductive film for resistive touch panels that are attached to
By setting the Sn content ratio to 70% by mass or less, it is possible to prevent the specific resistance of the oxide sintered body and the sputtering target material using the same from increasing, making it easier to perform DC sputtering. Advantages such as high-speed film formation can be enjoyed.

The oxide sintered body of the present invention and the sputtering target material using the same have a Si content of 3% by mass or more and 15% by mass or less in terms of SiO ₂ , preferably 4% by mass or more and 13% by mass or less. more preferably 6% by mass or more and 12% by mass or less, and still more preferably 7% by mass or more and 11% by mass or less.
By setting the content ratio of Si to 3% by mass or more, the film specific resistance of the transparent conductive film obtained by sputtering the oxide sintered body and the sputtering target material using the same can be increased. It can be used as a transparent conductive film for resistive touch panels that are attached to
By setting the Si content ratio to 15% by mass or less, as described below, the area ratio of the SiO ₂ phase in the oxide sintered body and the sputtering target material using the same, that is, the sintered body and The area ratio in the target material can be 3% or less, and abnormal discharge can be effectively suppressed when the target material is sputtered. In addition, it is possible to suppress an increase in specific resistance, facilitate DC sputtering, and enjoy advantages such as high-speed film formation by DC sputtering.

Furthermore, the oxide sintered body of the present invention and the sputtering target material using the same are composed of In, O and unavoidable impurities.
The content ratio of In in the sputtering target material is preferably 15% by mass or more and 47% by mass or less in terms of In ₂ O ₃ , more preferably 19% by mass or more and 44% by mass or less, and still more preferably 23% by mass or more and 39% by mass. % or less, and more preferably 26 mass % or more and 36 mass % or less.
Examples of unavoidable impurities include Fe, Cr, Ni, W and Zr, and the content of each is usually 100 ppm or less.

The oxide sintered body of the present invention and the sputtering target material using the same are preferably a composite oxide phase of In and Si, a composite oxide phase of In and Sn, an oxide phase of Sn, and a Si Containing an oxide phase is preferable from the point of being able to effectively suppress abnormal discharge when the target material is sputtered. From the viewpoint of making this advantage more remarkable, it is preferable to include an In ₂ Si ₂ O ₇ phase as the composite oxide phase of In and Si. The composite oxide phase of In and Sn preferably contains an In ₄ Sn ₃ O ₁₂ phase. The Sn oxide phase preferably includes a SnO ₂ phase. The oxide phase of Si preferably includes a SiO ₂ phase.

In the oxide sintered body of the present invention and the sputtering target material using the same, the area ratio of the SiO ₂ phase observed in the cross section of the oxide sintered body is preferably 3% or less, more preferably 0. 0.1% or more and 2.8% or less, more preferably 0.5% or more and 2.5% or less, and particularly preferably 0.6% or more and 2.4% or less. The smaller the area ratio of the SiO ₂ phase, the better, but the lower limit of the preferred range is determined because the oxide sintered body or the like contains Si within the range.

By setting the area ratio to 3% or less, abnormal discharge can be effectively suppressed when the sputtering target material is DC-sputtered. The reason for this is that the SiO ₂ phase is an insulating layer, so even when the oxide sintered body and the sputtering target material using the same have a low resistivity of about 10 ⁻¹ Ωcm, the area ratio of the SiO ₂ phase is 3. %, the discharge stability deteriorates and abnormal discharge tends to occur.

The oxide sintered body of the present invention and the sputtering target material using the same preferably have a relative density of 100% or more, more preferably 100.5% or more, particularly 101.0% or more. is preferred. By setting the relative density to 100% or more, it is possible to effectively suppress abnormal discharge when the sputtering target material is subjected to DC sputtering. This is because the increase in relative density reduces the volume resistance of the oxide sintered body and the sputtering target material using the same, thereby suppressing charge concentration during DC sputtering. This suppresses the formation of high-potential areas due to charge concentration and low-potential areas due to non-concentration of charges during DC sputtering, and makes it difficult for discharge to occur from high-potential areas to low-potential areas, thereby suppressing abnormal discharge. This is because it is thought that

Relative density is measured by the Archimedes method. Specifically, the air mass of the target material is divided by the volume (the mass of the target material in water/the specific gravity of water at the measurement temperature), and the percentage value for the theoretical density ρ (g/cm ³ ) based on the following formula (X) is calculated. Relative density (unit: %) was used.

(In the formula, C ₁ to C _i each indicate the content (% by mass) of the constituent material of the target material, and ρ ₁ to ρ _i are the density (g/cm ³ ) of each constituent material corresponding to C ₁ to C _i . indicates.)

The constituent substances of the oxide sintered body and the sputtering target material using the same are considered to be In ₂ O ₃ , SnO ₂ and SiO ₂ as described below, for example C ₁ : In ₂ O ₃ of the target material mass % of
ρ ₁ : Density of In ₂ O ₃ (7.18 g/cm ³ )
_C2 : Mass % of _SnO2 in the target material
ρ ₂ : Density of SnO ₂ (6.95 g/cm ³ )
C ₃ : % by mass of SiO ₂ in target material
ρ ₃ : Density of SiO ₂ (2.20 g/cm ³ )
is applied to the formula (X), the theoretical density ρ can be calculated.
The % by mass of In ₂ O ₃ , % by mass of SnO ₂ and % by mass of SiO ₂ in the target material may be obtained from the analysis result of each element of the target material by ICP emission spectrometry or the like.

Although the upper limit of the relative density is not particularly limited, it is, for example, 104.0%. Even if the relative density is increased further, it is difficult to effectively improve the effects described above, and the manufacturing cost of the oxide sintered body and the sputtering target material using the same tends to increase.

In the oxide sintered body of the present invention and the sputtering target material using the same, the relative density of the oxide sintered body is ρ _T , and when the oxide sintered body is divided into a plurality of measurement pieces, the measurement pieces Of the relative densities, when the relative density that deviates most from the relative density ρ _T is ρ _P , the difference in the relative density defined by the following formula (1) is ± 1% or less is preferable, more preferably ±0.5% or less, and particularly preferably ±0.3% or less.
ρ _T −ρ _P (1)
By reducing the difference in relative density, the charge concentration of the oxide sintered body and the sputtering target material using the same is suppressed, and the formation of high potential points due to charge concentration and low potential points due to charge non-concentration is prevented. Abnormal discharge is suppressed by suppressing and making it difficult for discharge to occur from a high-potential location to a low-potential location.

In the oxide sintered body of the present invention and the sputtering target material using the same, among the bulk resistance values measured at a plurality of points on the surface, Rmax is the maximum bulk resistance value, and Rmin is the minimum resistance value. , the value of Rmax / Rmin is preferably 1.0 or more and 2.0 or less, more preferably 1.1 or more and 1.8 or less, particularly 1.2 or more and 1.6 or less Preferably. By setting the value of Rmax/Rmin within the above range, abnormal discharge can be effectively suppressed when the sputtering target material is DC-sputtered.
The reason for this is that when the variation in the bulk resistance value of the oxide sintered body and the sputtering target material using the same increases, the potential at the high-resistance portion increases and the potential at the low-potential portion decreases. This is because discharge from a potential point to a low potential point is more likely to occur, and when the variation in the bulk resistance value is reduced, the discharge is less likely to occur, thereby suppressing abnormal discharge.

Furthermore, the Vickers hardness of the surface of the oxide sintered body of the present invention and the sputtering target material using the same is preferably 900 HV1 or more, more preferably 950 HV1 or more, particularly 1000 HV1 or more. preferable. By setting the Vickers hardness of the oxide sintered body and the sputtering target material using the same to 900 HV1 or more, the sputtering target material is prevented from cracking during sputtering, which is preferable.

Although the upper limit of the Vickers hardness of the oxide sintered body and the sputtering target material using the same is not particularly limited, it is, for example, 1100HV1. Even if the surface hardness is further improved, it is difficult to effectively improve the effects described above, and the manufacturing costs of the oxide sintered body and the sputtering target material using the same tend to increase.

The area of the sputtering surface of the sputtering target material of the present invention is preferably 70,000 mm ² or more, more preferably 120,000 mm ² or more, further preferably 157,500 mm ² or more, particularly preferably 200,000 mm ² or more. . As a result, when a large-area divided sputtering target is produced using a plurality of the sputtering target materials, the number of gaps between adjacent target materials can be reduced, and the gaps between the adjacent target materials during sputtering You can suppress particles that
Although the upper limit of the area of the sputtering surface is not particularly limited, it is usually 500000 mm ² .

Since the oxide sintered body of the present invention and the sputtering target material using the same have the properties as described above, it is possible to provide a sputtering target material in which the occurrence of abnormal discharge is further suppressed. It is possible to provide an oxide sintered body suitable for a variety of target materials.

The oxide sintered body of the present invention and the sputtering target material using the same can be suitably produced by the following method.
First, an indium (In) element source, a tin (Sn) element source, and a silicon (Si) element source are prepared. In general, _the indium (In) element source, tin (Sn) element source and silicon (Si) element source can be _In2O3 powder, _SnO2 powder and _SiO2 powder. The In ₂ O ₃ powder, the SnO ₂ powder and the SiO ₂ powder are mixed so that the contents of In, Sn and Si in the obtained sintered body are within the ranges described above, respectively, to prepare a raw material composition. The indium (In) element source, the tin (Sn) element source, and the silicon (Si) element source in the raw material composition are the In content ratio in terms of In ₂ O ₃ and the Sn content in terms of SnO ₂ in the oxide sintered body. and the Si content ratio in terms of _SiO2 , respectively.

Since the particles of each raw material powder are usually agglomerated, it is preferable to grind and mix in advance, or to grind while mixing.

There are no particular restrictions on the method of pulverizing the raw material powder or the method of mixing when obtaining the raw material composition. For example, the raw material powder can be put in a pot and pulverized or mixed with a ball mill.

When preparing the raw material composition, an indium (In) element source, a tin (Sn) element source and a silicon (Si) element source, such as In ₂ O ₃ powder, SnO ₂ powder and SiO ₂ powder It is preferred to add fatty acids, preferably saturated fatty acids having from 10 to 22 carbon atoms. By adding fatty acids, the surface lubricity of each element source is increased, so each element source is contained in the raw material composition in a uniform and dense state, and the uniformity and density of the raw material composition are improved. Therefore, it is possible to suppress uneven firing of the raw material composition, and the relative density difference and Rmax/Rmin of the oxide sintered body described above can be easily kept within the preferable ranges described above. Furthermore, the bending strength is improved.

Examples of saturated fatty acids include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid. These saturated fatty acids can be used individually by 1 type, or can be used in combination of 2 or more types. In addition to saturated fatty acids, unsaturated fatty acids such as palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, erucic acid, linoleic acid, linolenic acid and arachidonic acid can also be used. In particular, stearic acid, and industrial stearic acid (stearic acid + palmitic acid) can be preferably used from the viewpoint of easy availability. These unsaturated fatty acids can be used singly or in combination of two or more. Saturated fatty acids and unsaturated fatty acids can also be used in combination of one or more of each.

The obtained raw material composition can be molded as it is to form a molded body, which can be sintered. Alternatively, if necessary, a binder may be added to the raw material composition and molded to form a molded body. As this binder, one or two or more of binders used in obtaining a molded body in a known powder metallurgy method, such as polyvinyl alcohol and acrylic emulsion binders, can be used. Alternatively, a slurry may be prepared by adding a dispersion medium to the mixed powder, the slurry may be spray-dried to prepare granules, and the granules may be molded.

As for the forming method, methods conventionally employed in powder metallurgy, such as cold pressing and CIP (cold isostatic pressing), can be used.

Alternatively, the raw material composition may be temporarily pressed to produce a temporary molded body, and the pulverized powder obtained by pulverizing this may be pressed to produce a molded body. In addition, you may produce a molded object using wet molding methods, such as a slip casting method. The relative density of the compact is usually 50-75%.

A sintered body can be obtained by firing the molded body obtained as described above. The firing furnace used for firing is not particularly limited as long as the heating rate and cooling rate can be controlled during firing and cooling, and a firing furnace generally used for powder metallurgy may be used. An oxygen-containing atmosphere is suitable as the firing atmosphere.

From the viewpoint of increasing the density and preventing cracking, the heating rate is usually 50 to 400°C/h, and the cooling rate is usually 300°C/h or less, preferably 100°C/h or less.

The firing temperature is 1450°C or higher and 1500°C or lower, preferably 1460°C or higher and 1490°C or lower. The firing time is 4 hours or more and 20 hours or less, preferably 8 hours or more and 18 hours or less. By setting the firing temperature and firing time within the above ranges, the transition of the In ₂ Si ₂ O ₇ phase to the SiO ₂ phase is suppressed, and as described above, the SiO observed in the cross section of the oxide sintered body _{The two-} phase area ratio can be 3% or less.

The sputtering target material can be obtained by cutting out the sintered body obtained as described above into a desired shape and grinding the sintered body, if necessary.
The shape of the sputtering target material is not particularly limited, and may be flat, cylindrical, or the like.

The sputtering target material is usually used by bonding to the base material. The substrate is usually made of Cu, Al, Ti or stainless steel. As the bonding material, a bonding material used for bonding conventional ITO target materials, such as In metal, can be used. The bonding method is also the same as the conventional ITO target material bonding method.

Since the sputtering target material has a low specific resistance, DC sputtering can be performed, enabling high-speed film formation. Moreover, since the characteristics described above are satisfied, the occurrence of abnormal discharge is further suppressed.

[Evaluation of sputtering target material]
1. Elemental analysis of sputtering target material Elemental analysis in the sputtering target material is performed using a measuring instrument (name, model number): ICP emission spectrometer 720 ICP-OES (equipment manufacturer: Agilent Technologies), JIS standard: ICP-OES method. (JIS K 0116-2014).

2. Crystal Phase of Sputtering Target Material The crystal phase of the sputtering target material was measured using SmartLab (registered trademark) manufactured by Rigaku Corporation under the following conditions.
・Radiation source: CuKα ray ・Tube voltage: 40 kV
・Tube current: 30mA
・Scanning speed: 5deg/min
・Step: 0.02deg
・Scan range: 2θ = 20 degrees to 80 degrees

3. SiO ₂ phase area ratio of sputtering target material The cut surface obtained by cutting the sputtering target material was polished in stages using #180, #400, #800, #1000, and #2000 emery papers, and finally It was buffed to a mirror finish.
Then, using a scanning electron microscope (SU3500, manufactured by Hitachi High-Technologies Co., Ltd.), BSE-COMP images of 41.6 μm × 59.2 μm in a range of 10 fields of view were randomly photographed at a magnification of 3000 times. SEM images were obtained. Next, the area occupied by the SiO ₂ phase was drawn and filled in with different colors using Pictbear (manufactured by Fenrir). Next, using particle analysis software (Particle Analysis Version 3.0, manufactured by Sumitomo Metal Technology Co., Ltd.), the image in which the SiO ₂ phase was painted over was recognized, and this image was binarized. At this time, the conversion value was set so that one pixel was displayed in units of μm. After that, the areas of the SiO ₂ phase and the whole were calculated using particle analysis software, and the percentage of the SiO ₂ phase to the whole was obtained as the area ratio. The average value of the area ratios obtained in 10 fields of view was taken as the area ratio of the _SiO2 phase in the sintered body.

4. Relative Density of Sputtering Target Material and Its Variation Measured by the Archimedes method. Specifically, the air mass of the target material is divided by the volume (the mass of the target material in water/the specific gravity of water at the measurement temperature), and the theoretical density ρ (g/cm ³ ) based on the following formula (X1). was defined as the relative density (unit: %).

In the present invention, the constituent substances of the target material are considered to be In ₂ O ₃ , SnO ₂ and SiO ₂ , for example C ₁ : mass % of In ₂ O ₃ in the target material
ρ ₁ : Density of In ₂ O ₃ (7.18 g/cm ³ )
_C2 : Mass % of _SnO2 in the target material
ρ ₂ : Density of SnO ₂ (6.95 g/cm ³ )
C ₃ : % by mass of SiO ₂ in target material
ρ ₃ : Density of SiO ₂ (2.20 g/cm ³ )
is applied to the formula (X1) to calculate the theoretical density ρ.
The mass % of In ₂ O ₃ , the mass % of SnO ₂ , and the mass % of SiO ₂ can be determined from the analysis results of each element of the target material by ICP-OES analysis.
Variation in relative density is determined by dividing a rectangular target material into 3 squares in length and 5 squares in width, and measuring the relative density of each of the divided measurement pieces by the method described above. Of the 15 measured relative densities, the relative density ρ _P of the measurement piece that deviates most from the value of the relative density ρ _T of the target material before division is determined, and the relative density is calculated from the calculation formula of ρ _T - ρ _P. was calculated.

5. Bulk resistance and Rmax/Rmin of sputtering target materials
The bulk resistance of the sputtering target material is measured by using LORESTA (registered trademark)-GX MSP-T700 (series 4 probe probe TYPE ESP) manufactured by MITSUBISHI CHEMICAL ANALYTECH. , was measured in AUTO RANGE mode. 15 points were measured evenly on the surface of the oxide sintered body (see FIG. 1), and the arithmetic mean value of each measured value was taken as the bulk resistance value of the sintered body.
Rmax/Rmin of the sputtering target material was calculated by setting the maximum bulk resistance value as Rmax and the minimum resistance value as Rmin among the bulk resistance values measured at the 15 locations described above.

6. Vickers Hardness of Sputtering Target Material Vickers hardness tester MHT-1 (manufacturer: MATSUZAWA SEIKI) was used and measured according to JIS standard: JIS-R-1610:2003 (hardness test method for fine ceramics).
Specifically, the cut surface obtained by cutting the oxide sintered body is polished in stages using #180, #400, #800, #1000, and #2000 emery papers, and finally buffed. It was then polished to a mirror surface and used as the measurement surface. In addition, the surface opposite to the measurement surface was polished using the emery paper #180 so as to be parallel to the measurement surface. Using the test piece, the hardness was measured under a load of 1 kgf according to the hardness measurement method of JIS-R-1610:2003 (hardness test method for fine ceramics).

7. Bending Strength of Sputtering Target Material Autograph (registered trademark) AGS-500B (equipment manufacturer: Shimadzu Corporation) was used, and measured according to JIS standard: JIS-R-1601 (testing method for bending strength of fine ceramics). Specifically, using a sample piece (length 36 mm or more, width 4.0 mm, thickness 3.0 mm) cut from an oxide sintered body, JIS-R-1601 (fine ceramics bending strength test method) 3 It was measured according to the measurement method of point bending strength.

8. Evaluation of Abnormal Discharge of Sputtering Target Material DC sputtering was performed under the following conditions using a DC magnetron sputtering device (high rate sputtering device manufactured by Shinku Kikai Kogyo Co., Ltd.), an exhaust system cryopump and a rotary pump.
Ultimate degree of vacuum: 3 × 10 ^-6 [Pa]
Sputtering pressure: 0.65 [Pa]
Argon gas flow rate: 50 [cc]
Oxygen gas flow rate: 2.0 [cc]
Input power: 0.72 [kW]
Time: 24 hours The number of occurrences of abnormal discharge was evaluated as follows using an arcing counter (model: μArc Monitor MAM Genesis MAM data collector Ver. 2.02 (manufactured by LANDMARK TECHNOLOGY)).
A: little B: somewhat much C: much

[Examples 1 to 5]
In ₂ O ₃ powder, SnO ₂ powder, and SiO ₂ powder were mixed at the ratio shown in Table 1, then put into a resin pot and mixed for 21 hours by a dry ball mill to obtain a raw material composition. was prepared. Zirconia balls were used as media in the dry ball mill.

Next, the media and the raw material composition are classified by sieving, and 8.0% by mass of polyvinyl alcohol diluted with pure water to 5.5% by mass is added to the raw material composition with respect to the total mass of the raw material composition. 0.5% by mass of stearic acid was further added.

The above raw material composition was mixed with a mortar until the additives were blended and passed through a 5.5 mesh sieve. The obtained raw material composition was temporarily pressed under the condition of 200 kg/cm ² by a cold press method, and the obtained temporary compact was pulverized in a mortar.

The powder obtained by the pulverization was filled in a press mold and molded by a cold press method at a press pressure of 600 kg/cm ² for 60 seconds to obtain a compact.

The obtained compact was placed in a firing furnace, and oxygen was allowed to flow into the furnace at 1 L/h, and fired at 1480°C for 16 hours. After that, it was cooled at a cooling rate of 50°C/h. The surface of the obtained oxide sintered body was machined with a #170 whetstone to produce a sputtering target material having a surface Ra of 1.0 μm. The sputtering target material was rectangular with a long side dimension of 490 mm and a short side dimension of 370 mm.

Cracks in the target material were visually checked, and each characteristic was evaluated according to the evaluation method described above. Also, a Φ4-inch sample was cut out from the target material, and abnormal discharge was evaluated. Table 1 shows the results.

[Example 6]
A rectangular sputtering target material of 490 mm x 370 mm was manufactured in the same manufacturing method as in Example 3, except that the firing temperature was changed from 1480°C to 1500°C.
Cracks in the target material were visually confirmed, and each property was evaluated according to the evaluation method described above. Also, a Φ4-inch sample was cut out from the target material, and abnormal discharge was evaluated. Table 1 shows the results.

[Example 7]
A rectangular sputtering target material of 490 mm×370 mm was manufactured in the same manufacturing method as in Example 3, except that stearic acid was not added.
Cracks in the target material were visually confirmed, and each property was evaluated according to the evaluation method described above. Also, a Φ4-inch sample was cut out from the target material, and abnormal discharge was evaluated. Table 1 shows the results.

[Comparative Example 1]
A rectangular sputtering target material of 490 mm x 370 mm was manufactured in the same manufacturing method as in Example 3, except that the firing temperature was changed from 1480°C to 1550°C.
In this comparative example, since cracks occurred in the target material, a Φ4-inch sample was cut out from the uncracked portion to evaluate abnormal discharge. Cracks in the target material were visually confirmed, and each characteristic was evaluated according to the evaluation method described above. Table 1 shows the results.

[Comparative Example 2]
A rectangular sputtering target material of 490 mm x 370 mm was manufactured in the same manufacturing method as in Example 4, except that the firing temperature was changed from 1480°C to 1550°C.
In this comparative example, since cracks occurred in the target material, a Φ4-inch sample was cut out from the uncracked portion to evaluate abnormal discharge. Cracks in the target material were visually confirmed, and each characteristic was evaluated according to the evaluation method described above. Table 1 shows the results.

As is clear from Table 1, in Example 1-5, the contents of In, Sn and Si are within the scope of the present invention, and the SiO observed in the cross section of the oxide sintered body constituting the target material Since the area ratio of _{the two} phases is less than 3%, it has been found that the number of abnormal discharge occurrences is small and good DC sputtering is possible. However, in Example 6, the firing temperature was as high as 1500° C. and the area ratio of the SiO ₂ phase was as high as 3% compared to Example 1-5, so some abnormal discharge was observed in DC sputtering. rice field.

In Example 7, stearic acid was not added to the raw material composition, so each element source was contained in the raw material composition in a relatively non-uniform and coarse state, and the uniformity and density of the raw material composition decreased. are doing. Therefore, some abnormal discharge was observed in DC sputtering. The decrease in the uniformity and density of the raw material composition can be seen from Table 1 that the relative density difference, Rmax/Rmin and bending strength are lower than those of Examples 1-5.

On the other hand, in Comparative Examples 1 and 2, since the area ratio of the SiO ₂ phase observed in the cross section of the oxide sintered body constituting the target material exceeds 3%, abnormal discharge frequently occurs and good DC Sputtering turned out to be impossible.

In addition, when target materials of the following sizes were manufactured by the same manufacturing method as in Examples 1 to 7 and Comparative Examples 1 and 2, cracks were not observed in all target materials in the manufacturing methods of Examples 1 to 7, and the comparison In the production methods of Examples 1 and 2, cracks were observed in all target materials.
・400mm×500mm=200000mm ²
・350mm×450mm=157500mm ²
・300mm×400mm=120000mm ²
・250mm×350mm=87500mm ²
・200mm×350mm=70000mm ²

ADVANTAGE OF THE INVENTION According to this invention, the oxide sinter suitable for the sputtering target material by which generation|occurrence|production of abnormal discharge was suppressed further, and its manufacturing method are provided. Moreover, according to the present invention, a sputtering target material in which the occurrence of abnormal discharge is further suppressed is provided.
When sputtering is performed using the oxide sintered body according to the present invention, it is possible to form a film while suppressing abnormal discharge during sputtering compared to the case of using a conventional oxide sintered body. As a result, it is possible to suppress the generation of unnecessary defective products, thereby reducing the generation of waste. That is, it becomes possible to reduce the energy cost in disposing of those wastes. This will lead to sustainable management and efficient use of natural resources, as well as achieving decarbonization (carbon neutrality).

Claims

An oxide sintered body containing an indium (In) element, a tin (Sn) element and a silicon (Si) element,
Sn content is 50% by mass or more and 70% by mass or less in terms of SnO2 ,
The Si content is 3% by mass or more and 15% by mass or less in terms of SiO2 ,
The balance consists of indium, oxygen and unavoidable impurities,
An oxide sintered body, wherein the area ratio of the SiO 2 phase observed in the cross section of the oxide sintered body is 3% or less.
The oxide sintered body according to claim 1, which has a relative density of 100% or more.
Let the relative density of the oxide sintered body be ρ T ,
When the oxide sintered body is divided into a plurality of measurement pieces, and the relative density of the measurement pieces that deviates most from the relative density ρ T is ρ P ,
3. The oxide sintered body according to claim 1, wherein the difference in relative density defined by ρ T −ρ P is ±1% or less.
Among the bulk resistance values measured at a plurality of points on the surface of the oxide sintered body, when the maximum bulk resistance value is Rmax and the minimum resistance value is Rmin, the value of Rmax/Rmin is 1.0. 3. The oxide sintered body according to claim 1 or 2, wherein the ratio is not less than 2.0 and not more than 2.0.
The oxide sintered body according to claim 1 or 2, wherein the area ratio of the SiO2 phase observed in the cross section of the oxide sintered body is 0.1% or more and 2.8% or less.
Sn content is 55% by mass or more and 65% by mass or less in terms of SnO2 ,
The oxide sintered body according to claim 1 or 2 , wherein the content of Si is 6% by mass or more and 12% by mass or less in terms of SiO2.
The oxide sintered body according to claim 1 or 2, which has a Vickers hardness of 900HV1 or more.
A sputtering target material comprising the oxide sintered body according to claim 1 or 2.
The sputtering target material according to claim 8, wherein the area of the sputtering surface is 70000 mm2 or more.
preparing a raw material composition containing an indium (In) element source, a tin (Sn) element source and a silicon (Si) element source;
Molding the raw material composition to obtain a molded body,
A method for producing an oxide sintered body, comprising the step of firing the molded body,
A method for producing an oxide sintered body, wherein the compact is sintered at 1450° C. or higher and 1500° C. or lower for 4 hours or longer and 20 hours or shorter.
The manufacturing method according to claim 10, wherein the molding is sintered at 1460°C or higher and 1490°C or lower.
The production method according to claim 10 or 11, wherein the raw material composition contains a fatty acid.
The production method according to claim 12, wherein the fatty acid is a saturated fatty acid having 10 or more and 22 or less carbon atoms.