JP2002030429A - Ito sputtering target and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ITO sputtering target, by which yellow powder depositing on a noneroded part as well as the number of nodules occurring in an eroded part can be reduced. SOLUTION: The sputtering target is constituted of an ITO sintered compact having a composition consisting essentially of In, Sn and oxygen, having >=99% sintered density and >=180 μmΩ.cm bulk resistivity, and also having a composed essentially of a single-phase structure of fixbyite structure of In2O3. This target can be obtained by mixing powders of In2O3 and SnO3, compacting the resultant powder mixture, sintering the resultant green compact in a pure-oxygen air flow of 1,550 to <1,650 deg.C, cooling the resultant sintered compact at >=100 deg.C/h temperature-fall rate to <=1,350 deg.C, and then heat-treating it in a pure-oxygen air flow of 1,050-1,350 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sputtering target for forming an ITO transparent conductive film and a method for manufacturing the same.

[0002]

2. Description of the Related Art ITO (Indium) is a transparent conductive film.
Tin Oxide) thin films are manufactured by chemical film forming methods such as spray pyrolysis and CVD, electron beam evaporation, and the like.
It can be roughly classified into physical film forming methods such as a sputtering method. In particular, the sputtering method using an ITO target is easy to increase the area, has little change over time in the resistance value and transmittance of the obtained film, and is easy to control the film forming conditions. It is used.

In particular, the DC magnetron sputtering method in which a magnet is arranged behind a sputtering target and a magnetic field is present on the surface of the target to converge plasma is characterized by a high film-forming speed, and is used in a mass production apparatus. Many are adopted.

[0004] ITO thin films have features such as high conductivity and high transmittance, and can be easily processed in a fine manner. Therefore, they are used in a wide range of fields such as display electrodes for flat panel displays, window materials for solar cells, and antistatic films. Used throughout. In particular, in the field of flat panel displays such as liquid crystal display devices, in recent years, the size and definition have been advanced, and there has been an increasing demand for reducing the particle size of the ITO thin film, which is the display electrode.

[0005] Particles are caused by nodules and by yellow powder deposited on the non-erosion portion of the target.

[0006] Nodules are black deposits generated on the surface of an ITO target as the cumulative sputtering time increases when the ITO target is continuously sputtered in a mixed gas atmosphere of argon gas and oxygen gas. This black deposit, which is considered to be a lower oxide of indium, precipitates on the erosion part of the target and is likely to cause abnormal discharge during sputtering, and itself may be a source of foreign matter (particles). It has been known.

In order to reduce the generation of nodules, for example, Japanese Patent Application Laid-Open No. 08-060352 discloses a method in which the density of a target is set to 6.4 g / cm ³ or more and the surface roughness of the target is controlled. 06-158308
JP-A-07-166341 and JP-A-07-166341 have a single-phase structure with a relative density of 90% or more and a specific resistance (synonymous with the resistivity in the present invention) of 1 × 10 ⁻³ Ω · cm or less. In addition, JP-A-4-285163 has already reported that the relationship between the density D and the bulk resistivity ρ is specified.

[0008] However, although these methods had the effect of reducing nodules, they had little effect on the reduction of yellow powder generation.

The amount of yellow powder deposited on the non-erosion portion of the target surface increases as the sputtering time increases, and when it reaches a certain thickness or more, the yellow powder peels off from the target surface, floats in vacuum, and floats in the substrate surface. Will be attached to. The yellow powder changes its direction by colliding with gas particles (argon, oxygen, etc.) in the vacuum chamber before the target material beaten out from the erosion portion reaches the opposing substrate, and is deposited on the target surface. It is believed that.

When this yellow powder adheres to the substrate, it degrades the display quality of a liquid crystal display device or the like and causes a defect.
Significantly lowers product yield. As means for solving such a problem, for example, JP-A-6-306
No. 592 and Japanese Unexamined Patent Application Publication No. 11-92923 report a method for increasing the adhesion strength of yellow powder adhered to a non-erosion portion. However, an ITO target that reduces the generation of yellow powder itself has not been reported.

Thus, development of a new ITO target capable of simultaneously reducing both nodules and yellow powder has been desired.

[0012]

The problem to be solved by the present invention is that the IT
It is an object of the present invention to provide an ITO sputtering target capable of reducing the amount of both nodules generated in the erosion portion and yellow powder deposited in the non-erosion portion as the cumulative use time of the O target increases.

[0013]

Means for Solving the Problems The present inventors have conducted intensive studies on measures to reduce nodules and yellow powders, and determined the amount of nodules and yellow powders generated with the bulk characteristics of the sintered body used for the target. There is a correlation, the density of the sintered body is set to 99% or more, and the bulk resistivity is set to 18%.
It has been found that the generation amount can be reduced by using an ITO sintered body having a single phase structure of substantially a bixbyite structure of indium oxide as a target, which is set to 0 μΩ · cm or more.

The sintered body used for the ITO target is
There have been many studies on densification, and various reports have been made. FIG. 1 of JP-A-4-285163 described above shows the relationship between density and resistivity. It is shown that the resistivity decreases sharply when it becomes. As described above, the bulk resistivity generally decreases as the density increases.

However, the ITO sintered body used for the sputtering target of the present invention is characterized in that it has a high density (99% or more) and a high bulk resistivity. I
In order to increase the resistance while keeping the density of the TO sintered body high and without adding a third element, a method of adding oxygen to the sintered body and filling oxygen defects in the sintered body can be considered. . However, when oxygen is simply applied, a part of the sintered body is changed from an In ₂ O ₃ bixbyite structure to In ₄ S
It changes to an intermediate compound having a fluorite structure represented by n ₃ O ₁₂ . The formation of this intermediate compound is not preferable because nodules are easily generated. Therefore, an advanced sintering technique is required to provide oxygen, fill oxygen defects, and increase bulk resistance without forming an intermediate compound.

At present, it is not clear why the volume amount of the yellow powder can be reduced by defining the density and the resistivity of the ITO sintered body as described above, but the bulk characteristics as described above are obtained. It is considered that this causes a difference in the form (eg, ionization state) of the particles ejected from the target during sputtering.

In addition, IT having such bulk characteristics
O sintered body is a mixture of indium oxide and tin oxide powder,
After molding and sintering in a pure oxygen stream of 1550 ° C. or more and less than 1650 ° C., the temperature is lowered at a rate of 100 ° C./hour or more.
After cooling to a temperature of 50 ° C or less,
They have been found to be obtained by heat treatment in a pure oxygen stream at 350 ° C. or lower.

That is, the present invention relates to substantially indium,
It is made of tin and oxygen, has a sintering density of 99% or more, a bulk resistivity of a sintered body of 180 μΩ · cm or more, and substantially has a bixbite single-phase structure of In ₂ O _3. A sputtering target composed of an ITO sintered body, and powders of indium oxide and tin oxide are mixed, molded, sintered in a pure oxygen gas stream of 1550 ° C or more and less than 1650 ° C, and then cooled at a rate of 100 ° C / hour or more. The present invention relates to a method for manufacturing an ITO sputtering target, comprising cooling to a temperature of 1350 ° C. or lower and then performing heat treatment in a pure oxygen gas stream of 1050 ° C. to 1350 ° C.

Hereinafter, the present invention will be described in detail.

According to the present invention, the sintered body is substantially composed of indium, tin and oxygen, has a sintering density of 99% or more, a bulk resistivity of a sintered body of 180 μΩ · cm or more, and substantially contains In ₂ O ₃ . A sputtering target made of an ITO sintered body having a bixbite single-phase structure can be manufactured, for example, by the following method.

First, an indium oxide powder and a tin oxide powder are charged into a ball mill pot at a desired ratio, and dry or wet mixed to prepare a mixed powder. The average particle size of the powder used is preferably 1.5 μm or less, more preferably 0.1 to 1.5 μm. By using such a powder, an effect of increasing the density of the sintered body can be obtained.

In the present invention, the content of tin oxide in the mixed powder is preferably 5 to 15% by weight as SnO ₂ / (In ₂ O ₃ + SnO ₂ ). By doing so, the resistivity of the thin film obtained when the film is formed by the sputtering method is reduced.

Here, the tap density of the mixed powder of the tin oxide powder and the indium oxide powder is adjusted to 1.8 g / cm ³ or more. If the tap density is less than 1.8 g / cm ³ , a compact having sufficient strength cannot be obtained when the mixed powder is compacted and subjected to the sintering step, and as a result, cracks are formed in the sintered compact during sintering. May occur. Further, in order to obtain a mixed powder having a tap density equal to or higher than the above-described value, for example, the mixed powder is obtained by mixing the mixed powder for 10 hours or more by the above-described mixing means.

The tap density referred to here is a physical property value of the powder generally used in the powder handling industry. For example, a powder for measuring the tap density is put in a measuring cylinder, and then the scalpel containing the powder is measured. It is a value calculated from the volume and weight of the powder obtained by tapping the cylinder until the bulk of the powder no longer changes.

The powder thus obtained is molded by a molding method such as a press method or a casting method to produce an ITO molded body. When a molded body is manufactured by press molding, after filling the mixed powder into a mold having a predetermined size, the molded body is pressed by a press at a pressure of 100 to 300 kg / cm ² to obtain a molded body. At this time, a binder such as PVA may be added as needed. On the other hand, when a molded body is manufactured by the casting method, the mixed powder is mixed with water, a binder and a dispersant to form a slurry, and the thus obtained 5
A slurry having a viscosity of 0 to 5000 centipoise is poured into a casting mold to produce a molded article.

Next, the thus obtained molded body is subjected to a treatment by a cold isostatic press (CIP) as required.
At this time, the pressure of the CIP is 1 ton in order to obtain a sufficient consolidation effect.
On / cm ² or more, preferably ² to 5 ton / cm ² is desirable.

When molding is performed by the casting method, CI
5-20 at a temperature of 300-500 ° C. to remove water and organic substances such as a binder remaining in the molded body after P.
It is preferable to perform a drying treatment and a binder removal treatment for about an hour. Even when molding is performed by a press method, when a binder is used at the time of molding, it is preferable to perform the same binder removal treatment.

Next, the compact thus obtained is sintered. The rate of temperature rise is not particularly limited, but from the viewpoint of shortening the sintering time and preventing cracking, it is 10 to 400 ° C. /
Preferably, it is time.

The sintering temperature is 1550 ° C. or higher, 1650 ° C.
Less than 1,580 to 1,620 ° C. By doing so, a high-density sintered body can be obtained,
The solid solution of SnO _{2 into} the In ₂ O ₃ bixbyite structure is promoted, and the formation of an intermediate compound phase of In ₄ Sn ₃ O ₁₂ is suppressed, so that a substantially single-phase structure is obtained, which is preferable. At a temperature of 1650 ° C. or higher, solid solution is promoted, but it is not preferable because SnO ₂ evaporates and a load on a sintering furnace increases.

Here, the “substantially single-phase structure” means that the diffraction peak intensity (Ib) of the (211) plane of In ₂ O ₃ obtained by XRD and 50.000 when Cu is used as the X-ray source. 7
Degree (2θ) (lower angle side of (440) peak of In ₂ O ₃ ), the peak height ratio of the diffraction peak intensity (If) of the intermediate compound, (If / Ib) × 100 (%) is 20. 0
% Or less, preferably 16% or less, more preferably 14%
It means the following.

In the present invention, the background is not canceled on the XRD profile obtained by continuous scanning of θ-2θ using a Cu X-ray source and a graphite monochromator, and the influence of Kα2 is not affected by Rachi.
After removal using the Nger method with (Kα2 / Kα1) = 0.5, the peak height ratio was simply determined.

It is desirable that the sintering time is 5 hours or more, preferably 5 to 30 hours, in order to obtain a sufficient density increasing effect.

The atmosphere during the sintering is an oxygen flow, and the oxygen flow rate (L / min) when oxygen is introduced into the furnace during the sintering.
And the ratio of the charged amount (kg) of the compact (charged weight / oxygen flow)
Is set to 1.0 or less. This makes it easier to obtain a high-density sintered body.

At the time of cooling, the temperature is lowered at a rate of 100 ° C./hour or more until at least 1350 ° C. If it is slower than this, SnO ₂ dissolved in the In ₂ O ₃ lattice cannot maintain a solid solution state and an intermediate compound is formed, which is not preferable. The cooling atmosphere is at least an oxygen atmosphere, preferably an oxygen gas atmosphere. Here, when the supply of oxygen is cut off, an intermediate compound phase is hardly formed, but it is not preferable because oxygen escapes from the In ₂ O ₃ lattice to form oxygen defects and lower the bulk resistivity. In this case, the generation amount of the yellow powder increases.

The temperature is lowered to 1350 ° C. or less. Preferably, it is from room temperature to 1350 ° C, more preferably from room temperature to 1250 ° C. Here, when cooled to around room temperature, it may be transferred to a furnace dedicated to heat treatment.
Further, at the time of cooling to a temperature range of 1050 ° C. or more and 1350 ° C. or less, the next heat treatment step may be continuously performed.

The heat treatment step is performed for the purpose of filling oxygen defects in the sintered body. Heat treatment temperature is 1050 ° C or more,
1350 ° C. or less. Preferably, 1100 ° C or higher,
The temperature is 1300 ° C or lower, particularly preferably 1180 ° C or higher and 1220 ° C or lower. If the heat treatment temperature is low, the effect of filling oxygen defects in the sintered body is reduced, and high bulk resistance is not achieved. If too high, an intermediate compound layer is formed, which is not preferable.

The atmosphere during the heat treatment is such that the ratio of the oxygen flow rate (L / min) when introducing oxygen into the furnace during sintering and the charged amount (kg) of the compact (charged weight / oxygen flow rate) is 1.0. It is preferable to set the following.

The heat treatment time is 3 hours or more, preferably 5 hours.
It is longer than or equal to 20 hours. This makes it possible to fill the oxygen vacancies with oxygen while suppressing the formation of the intermediate compound phase. Then, it cools and takes out an ITO sintered compact from a sintering furnace. The ITO sintered body thus obtained is
When the density is 99% or more and the bulk resistivity is 180 μΩ · cm or more, a single-phase structure of substantially In ₂ O ₃ bixbite is obtained.

Since the higher the sintering density, the more the nodule reduction effect can be obtained, it is preferably 99.5% or more. It is more preferably at least 99.7%, particularly preferably at least 99.8%.

The higher the bulk resistivity is, the higher the yellow powder reduction effect is obtained, so that the bulk resistivity is 180 μΩ · cm or more, preferably 190 μΩ · cm. Although there is no particular upper limit, it is difficult to maintain the bulk resistivity at 250 μΩ · cm or more while maintaining the density at 99% or more even by using the method of the present invention.

The sintering density (D) in the present invention is defined as
The relative values with respect to the theoretical density (d) obtained from the arithmetic mean of the true densities of In ₂ O ₃ and SnO ₂ are shown. The theoretical density (d) obtained from the arithmetic mean means that the mixing amounts of In ₂ O ₃ and SnO ₂ powders are a and b in the target composition.
(G), the true densities of 7.18 and 6.9, respectively.
Using 5 (g / cm ³ ), d = (a + b) / ((a / 7.18) + (b / 6.9)
5) Required by Assuming that the measured density of the sintered body is d1,
The sintering density is obtained by the formula: D = d1 / d × 100 (%).

Next, the obtained sintered body is ground into a desired shape and, if necessary, is bonded to a backing plate made of oxygen-free copper or the like by using indium solder or the like, thereby obtaining the ITO of the present invention. A sputtering target can be obtained.

The obtained target is placed in a sputtering apparatus, and sputtering is performed by applying a dc or rf electric field using an inert gas such as argon and, if necessary, an oxygen gas as a sputtering gas. ITO thin film can be formed on the substrate of
At this time, the effect of the present invention that the amount of the yellow powder deposited on the non-erosion portion is reduced is exhibited.

[0044]

(Example 1) 90 parts by weight of indium oxide powder having an average particle diameter of 0.5 μm and 10 parts by weight of tin oxide powder having an average particle diameter of 0.5 μm were placed in a polyethylene pot, and were subjected to a dry ball mill for 72 hours. The mixture was mixed to prepare a mixed powder. When the tap density of the mixed powder was measured, it was 2.0
g / cm ³ .

This mixed powder was placed in a mold and was weighed at 300 kg /
It was pressed at a pressure of cm ² to obtain a molded body. This compact was subjected to a CIP treatment at a pressure of 3 ton / cm ² .
Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the following conditions.

(Sintering Conditions) Heating rate: 100 ° C./hour, sintering temperature: 1600 ° C., sintering time: 6 hours, atmosphere: 800 ° C. at elevated temperature to 4 ° at lower temperature
Pure oxygen gas is introduced into the furnace up to 00 ° C. at (charge weight / oxygen flow rate) = 0.8, and the temperature is lowered from 1600 ° C. to 120 ° C.
After cooling to 100 ° C./hour up to 0 ° C., and then to 50 ° C./hour room temperature, the sintered body was transferred to a heat treatment furnace and heat-treated under the following conditions.

(Heat treatment conditions) Temperature rise rate: 100 ° C./hour, heat treatment temperature: 1200 ° C., heat treatment time: 10 hours, temperature fall rate: 100 ° C./hour, atmosphere: pure oxygen gas from the start of temperature rise to the end of temperature fall The density of the obtained sintered body was measured by the Archimedes method, the bulk resistivity was measured by the four probe method, and the crystallinity was measured by X-ray diffraction. Table 1 shows the obtained results.

The sintered body was processed into a 5 × 7 inch, 6 mm thick sintered body by a wet processing method, and bonded to an oxygen-free copper backing plate using indium solder to obtain a target. The target was continuously discharged under the following sputtering conditions, and the amount of yellow powder generated was examined.

(Sputtering conditions) DC power: 300 W, gas pressure: 7.0 mTorr, sputtering gas: Ar + oxygen, oxygen gas concentration (O ₂ / Ar) in the sputtering gas: 0.05%, discharge time:
66 hours (the remaining thickness of the target is about 1 mm) Here, the oxygen gas concentration was set to a value at which the resistivity of the obtained thin film decreased most.

The amount of nodules generated and the amount of yellow powder generated after completion of the experiment were examined. The nodule generation amount was measured by performing image processing on a photograph of the appearance of the target after discharge using a computer. The yellow powder was evaluated based on the thickness of the thickest portion deposited on the target. Table 1 shows the measurement results. Both nodules and yellow powders generated a small amount.

(Embodiment 2) In the same manner as in Embodiment 1,
An O molded body was manufactured and CIP treatment was performed. Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the following conditions.

(Sintering conditions) Heating rate: 100 ° C./hour, sintering temperature: 1600 ° C., sintering time: 6 hours, atmosphere: 800 ° C. at the time of temperature increase and 1 at the time of temperature decrease
Pure oxygen gas was introduced into the furnace up to 200 ° C. at (charged weight / oxygen flow rate) = 0.8, and the temperature was lowered from 1600 ° C. to 110 ° C.
After cooling to 0 ° C. and 100 ° C./hour to 1100 ° C., a heat treatment was subsequently performed in the same furnace. The heat treatment conditions are as follows.

(Heat treatment conditions) Heat treatment temperature: 1100 ° C., heat treatment time: 10 hours, temperature drop rate: 100 ° C./hour, atmosphere: the same conditions as in sintering, until the end of temperature drop. The bulk resistivity and crystallinity were examined. Table 1 shows the obtained results.

This sintered body was targeted by the same method as in Example 1, and the same film formation evaluation as in Example 1 was performed. Table 1 shows the results. Both nodules and yellow powders generated a small amount.

(Example 3) In the same manner as in Example 1,
An O molded body was manufactured and CIP treatment was performed. Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the following conditions.

(Sintering conditions) Heating rate: 100 ° C./hour, sintering temperature: 1600 ° C., sintering time: 6 hours, atmosphere: 800 ° C. at the time of temperature increase and 1 at the time of temperature decrease
Pure oxygen gas was introduced into the furnace up to 300 ° C. at (charge weight / oxygen flow rate) = 0.8, and the temperature was lowered from 1600 ° C. to 130 ° C.
After cooling to 0 ° C., 100 ° C./hour, and 1300 ° C., a heat treatment was subsequently performed in the same furnace. The heat treatment conditions are as follows.

(Heat Treatment Conditions) Heat treatment temperature: 1300 ° C., heat treatment time: 10 hours, temperature drop rate: 100 ° C./hour, atmosphere: the same conditions as in sintering, until the end of temperature drop. The bulk resistivity and crystallinity were examined. Table 1 shows the obtained results.

This sintered body was targeted by the same method as in Example 1, and the same film formation evaluation as in Example 1 was performed. Table 1 shows the results. Both nodules and yellow powders generated a small amount.

(Embodiment 4) In the same manner as in Embodiment 1,
An O molded body was manufactured and CIP treatment was performed. Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the following conditions.

(Sintering conditions) Heating rate: 100 ° C./hour, sintering temperature: 1600 ° C., sintering time: 7 hours, atmosphere: 800 ° C. at the time of temperature increase and 1 at the time of temperature decrease
Pure oxygen gas is introduced into the furnace up to 200 ° C. at (charge weight / oxygen flow rate) = 0.8, and the temperature decreasing rate is from 1600 ° C. to 120 ° C.
After cooling to 0 ° C., 400 ° C./hour and 1200 ° C., a heat treatment was subsequently performed in the same furnace. The heat treatment conditions are as follows.

(Heat treatment conditions) Heat treatment temperature: 1200 ° C., heat treatment time: 10 hours, temperature drop rate: 100 ° C./hour, atmosphere: the same conditions as in sintering, until the end of temperature drop. The bulk resistivity and crystallinity were examined. Table 1 shows the obtained results.

This sintered body was targeted by the same method as in Example 1, and the same film formation evaluation as in Example 1 was performed. Table 1 shows the results. Both nodules and yellow powders generated a small amount.

(Embodiment 5) In the same manner as in Embodiment 1, the IT
An O molded body was manufactured and CIP treatment was performed. Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the following conditions.

(Sintering conditions) Heating rate: 100 ° C./hour, sintering temperature: 1550 ° C., sintering time: 7 hours, atmosphere: 800 ° C. at the time of temperature increase and 1 at the time of temperature decrease
Pure oxygen gas is introduced up to 200 ° C. into the furnace at (charge weight / oxygen flow rate) = 0.8, and the temperature is reduced from 1550 ° C. to 120 ° C.
After cooling to 0 ° C., 100 ° C./hour and 1200 ° C., a heat treatment was subsequently performed in the same furnace. The heat treatment conditions are as follows.

(Heat treatment conditions) Heat treatment temperature: 1200 ° C., heat treatment time: 10 hours, temperature drop rate: 100 ° C./hour, atmosphere: the same conditions as in sintering, until the end of temperature drop. The bulk resistivity and crystallinity were examined. Table 1 shows the obtained results.

This sintered body was targeted by the same method as in Example 1, and the same film formation evaluation as in Example 1 was performed. Table 1 shows the results. Both nodules and yellow powders generated a small amount.

Comparative Example 1 In the same manner as in Example 1,
An O molded body was manufactured and CIP treatment was performed. Next, this compact was placed in a pure oxygen atmosphere sintering furnace, sintered under the same conditions as in Example 1, and cooled to room temperature. No heat treatment was performed after sintering.

The density, bulk resistivity and crystallinity of the obtained sintered body were examined. Table 1 shows the obtained results.

This sintered body was targeted by the same method as in Example 1, and the same film formation evaluation as in Example 1 was performed. Table 1 shows the results. Although nodule generation was small, many yellow powders were deposited.

(Comparative Example 2) In the same manner as in Example 1,
An O molded body was manufactured and CIP treatment was performed. Next, the compact was placed in a pure oxygen atmosphere sintering furnace and the sintering temperature was set to 1
Sintering was performed under the same conditions as in Example 1 except that the temperature was 500 ° C.
Heat treatment was performed.

The density, bulk resistivity and crystallinity of the obtained sintered body were examined. Table 1 shows the obtained results.

This sintered body was targeted by the same method as in Example 1, and the same film formation evaluation as in Example 1 was performed. Table 1 shows the results. Although the generation amount of the yellow powder was small, many nodules were generated.

(Comparative Example 3) In the same manner as in Example 1, the IT
An O molded body was manufactured and CIP treatment was performed. Next, this compact was placed in a pure oxygen atmosphere sintering furnace, and sintering and heat treatment were performed under the same conditions as in Example 1 except that the temperature reduction rate from 1600 ° C. to 1200 ° C. was 50 ° C./hour. Carried out.

The density, bulk resistivity and crystallinity of the obtained sintered body were examined. Table 1 shows the obtained results.

This sintered body was targeted by the same method as in Example 1, and the same film formation evaluation as in Example 1 was performed. Table 1 shows the results. Although the generation amount of the yellow powder was small, many nodules were generated.

(Comparative Example 4) In the same manner as in Example 1, the IT
An O molded body was manufactured and CIP treatment was performed. Next, this compact was placed in a pure oxygen atmosphere sintering furnace, and sintering and heat treatment were performed under the same conditions as in Example 1 except that the heat treatment temperature was 1400 ° C.

The density, bulk resistivity and crystallinity of the obtained sintered body were examined. Table 1 shows the obtained results.

This sintered body was targeted by the same method as in Example 1, and the same film formation evaluation as in Example 1 was performed. Table 1 shows the results. Although the generation amount of the yellow powder was small, many nodules were generated.

(Comparative Example 5) In the same manner as in Example 1, the IT
An O molded body was manufactured and CIP treatment was performed. Next, this compact was placed in a pure oxygen atmosphere sintering furnace, and sintering and heat treatment were performed under the same conditions as in Example 1 except that the heat treatment temperature was set to 1000 ° C.

The density, bulk resistivity and crystallinity of the obtained sintered body were examined. Table 1 shows the obtained results.

This sintered body was targeted by the same method as in Example 1, and the same film formation evaluation as in Example 1 was performed. Table 1 shows the results. Although nodule generation was small, many yellow powders were deposited.

(Comparative Example 6) In the same manner as in Example 1, the IT
An O molded body was manufactured and CIP treatment was performed. Next, this compact was placed in a pure oxygen atmosphere sintering furnace, and sintering and heat treatment were performed under the same conditions as in Example 1 except that the atmosphere during the heat treatment was air.

The density, bulk resistivity and crystallinity of the obtained sintered body were examined. Table 1 shows the obtained results.

This sintered body was targeted by the same method as in Example 1, and the same film formation evaluation as in Example 1 was performed. Table 1 shows the results. Although nodule generation was small, many yellow powders were deposited.

[0085]

[Table 1]

[0086]

According to the present invention, by producing a thin film by a sputtering method using a sputtering target composed of an ITO sintered body, the generation amount of nodules and yellow powder is small, and the adhesion of particles to a substrate is reduced. Such an ITO target can be provided.

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Claims (5)

[Claims] 1. A bixbite structure substantially composed of indium, tin and oxygen, having a sintered density of 99% or more, a bulk resistivity of a sintered body of 180 μΩ · cm or more, and substantially indium oxide. A sputtering target comprising an ITO sintered body, characterized by having a single-phase structure. 2. The sputtering target comprising the ITO sintered body according to claim 1, wherein the bulk resistivity is 250 μΩ · cm or less. 3. Indium oxide and tin oxide powders are mixed and molded, sintered in a pure oxygen gas stream of 1550 ° C. or more and less than 1650 ° C., and then cooled to a temperature of 1350 ° C. or less at a rate of 100 ° C./hour or more. Cooled to 1050 ° C-135
IT characterized by heat treatment in a pure oxygen stream at 0 ° C
A method for manufacturing an O sputtering target. 4. The ratio of the oxygen flow rate (L / min) when introducing oxygen into the furnace during sintering and the charged amount (kg) of the compact (charged weight / oxygen flow rate) is 1.0 or less. The method for producing an ITO sputtering target according to claim 3, wherein: 5. The ratio of the oxygen flow rate (L / min) when introducing oxygen into the furnace during heat treatment and the charged amount (kg) of the compact (charged weight / oxygen flow rate) is 1.0 or less. The method for manufacturing an ITO sputtering target according to claim 3.