JP3215392B2 - Metal oxide sintered body and its use - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a conductive metal oxide sintered body, a target, a thin film, and uses thereof.

[0002]

2. Description of the Related Art ITO (Indium Tin Oxi)
de) The thin film has characteristics such as high conductivity and high transmittance,
Furthermore, since fine processing can be easily performed, display electrodes for flat panel displays, resistive touch panels,
Window materials for solar cells, antistatic films, electromagnetic wave prevention films, antifogging films,
It is used in a wide range of fields such as sensors. The method for producing such an ITO thin film is spray pyrolysis, CV
The method can be broadly classified into a chemical film formation method such as a D method and a physical film formation method such as an electron beam evaporation method, an ion plating method, and a sputtering method. Among these, the physical film formation method
Since it is a film forming method that can easily form a film on a large area and obtain a high-performance film, it is used in various fields.

[0003] When an ITO thin film is manufactured by a physical film-forming method, the raw materials to be used (a sputtering target in the case of a sputtering method, and a deposition material in the case of a vacuum evaporation method and an ion plating method) include metal indium and metal tin. Alloy or a composite oxide composed of indium oxide and tin oxide is used. this house,
The method using the ITO composite oxide has a smaller change with time in the resistance and transmittance of the obtained film than the method using the IT alloy, and the film forming conditions can be easily controlled. It has become mainstream.

[0004] With the development of the information society in recent years, the technical level required for the flat panel display, the touch panel and the like is increasing. For this reason, characteristics that have not been particularly problematic for ITO thin films have been pointed out as problems. Specifically, it is a problem in the film structure and durability of the ITO thin film.

First, the problems in the structure of the film will be described.

When an ITO thin film is formed at room temperature, an amorphous film can be obtained except for special conditions. However, in consideration of heat resistance resistance stability and weather resistance, it is preferable to crystallize a thin film. The crystallization temperature of ITO is 150 ° C., and it is necessary to form a film at a film formation temperature higher than this temperature in order to obtain a crystallized film. However, after a film forming process using plasma such as sputtering or ion plating, crystalline ITO
When a thin film is formed, a domain structure characteristic of the ITO thin film is formed. The domain structure is a structure in which crystal grains of 10 to 30 nm with well-aligned crystal orientations as shown in FIG. 1 are gathered to form a crystal grain region of 200 to 300 nm. This domain structure is a collection of small grains having different crystal orientations, and is mainly composed of (1
11), (110) or (100).
Further, it has a feature that the resistance to plasma damage varies depending on the orientation plane. For this reason, the sputtering speed when the formed film is re-sputtered by plasma during the film formation differs. As a result, as shown in FIG. 2, a thin film having a thick surface on the (100) plane and a thin surface on the (110) plane is formed. A film having such a structure is found in a film manufactured by using a plasma such as a sputtering method or ion plating.

On the other hand, in the field of thin-film displays in which ITO thin films are often used, particularly in the field of liquid crystal displays, the screens are becoming larger and finer at a rapid pace. Therefore, as a demand for a transparent conductive film, a film having a large area, low resistance, and easy microfabrication is required.

However, when a film is formed at a high substrate temperature by using a sputtering method capable of forming a uniform film over a large area, a film having a severe surface irregularity as described above is formed, and etching residues are easily generated. That is, there has been a problem that a thin film unsuitable for fine processing is formed.

Next, the problem of durability will be described. I
The TO thin film has a problem that the resistivity of the thin film increases in a high-temperature or high-humidity environment. For example, with respect to heat resistance, it is known that the resistivity increases by 5 to 30% when left in the air at a temperature of 200 ° C. or higher for 30 minutes. As for the moisture resistance, 60 ° C., 90% RH
For 500 hours, the resistivity is 10-20.
It is known to increase by 0%.

The above-mentioned phenomenon of an increase in resistivity becomes more remarkable as the thickness of the ITO thin film becomes thinner. For this reason, it has been a particular problem in the field of a resistive touch panel using an ITO thin film with a small thickness, and has been an important problem to be solved.

In addition, discharge stability, nodule (ITO)
In order to reduce the amount of black foreign substances formed on the target surface when the target is continuously sputtered in a mixed gas atmosphere of argon gas and oxygen gas)
Studies on increasing the sintering density of ITO sintered bodies have been actively conducted. For example, a method in which sintering is carried out in a pressurized oxygen atmosphere of 1 atm or more as in Japanese Patent Publication No. 5-30905, and an average particle size of 0.1 μm as in Japanese Patent Application Laid-Open No. 4-160047.
The following indium oxide powder and tin oxide powder are heat-treated at a temperature of 1350 ° C. or more in an oxygen atmosphere, and the obtained heat-treated powder is pulverized again, and then subjected to a temperature of 500 to 1000 ° C. or more and a pressure of 100 kg / cm ² or more. A method of sintering in an oxygen-free atmosphere. As described in US Pat. No. 5,433,901, sintering is performed by adding 0.05 to 0.25% by weight of Al ₂ O ₃ , Y ₂ O ₃ or MgO as a sintering aid. A method of doing so has been proposed. However, in these inventions, there is a problem that the above-mentioned problems concerning the flatness and durability of the film cannot be solved.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide an IT device for a transparent electrode of a flat panel display.
Even when an O thin film is formed at a substrate temperature higher than the crystallization temperature, it is an object to provide a flat thin film having no domain structure and excellent in etching characteristics. Another object of the present invention is to provide a transparent conductive film which is excellent in heat resistance and moisture resistance and has a small rate of change in resistivity even when used in a thin film region such as a touch panel.

Furthermore, used in forming such a thin film is to provide a scan sputtering target.

[0014]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a conductive metal oxide obtained by doping a different element into ITO, and as a result, have found that the above problems can be solved in an ITO thin film containing magnesium as a dopant. We have found and completed the present invention.

That is, the present invention provides a method for producing substantially indium,
Consists of tin, magnesium and oxygen, magnesium
Is the atomic ratio of Mg / (In + Sn + Mg)2.4~ 2
Contained at a rate of 0.0%With the relative density
98% or moreMetal oxide sintered body characterized by the above,
A sputtering target using the sintered body, Real
From indium, tin, magnesium and oxygen
Magnesium is the atom of Mg / (In + Sn + Mg)
By ratio2.4That it is contained at a rate of ~ 20.0%
A transparent conductive film, and Including the transparent conductive film
This is related to the device that is used.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

[0017] according to the present invention sintered body, the sputtering target consisting of a sintered body, the thin film and the device comprising the thin film is prepared by the following method.

The method for producing the magnesium-containing ITO sintered body is not particularly limited, but as the sintered body for use in the sputtering target, the density of the obtained sintered body is preferably 98% or more. Such a sintered body can be manufactured, for example, by the following method.

The relative density (D) referred to in the present invention is:
The relative values with respect to the theoretical density (d) obtained from the arithmetic mean of the true densities of In ₂ O ₃ , SnO ₂ and MgO are shown. The theoretical density (d) determined from the arithmetic mean is In ₂ O ₃ , SnO ₂ and MgO in the target composition.
Assuming that the mixing amount of the powder is a, b, c (g), the true densities of the respective powders are 7.179, 6.95, 3.65 (g / c).
Using m ³ ), d = (a + b + c) / ((a / 7.179) + (b / 6.95) + (c / 3.65)). Assuming that the measured density of the sintered body is d1,
The relative density (%) is obtained by the formula: d1 / d × 100.

First, powders are mixed. Indium oxide powder, tin oxide powder, and magnesium oxide powder may be mixed, or tin oxide solid solution indium oxide powder and magnesium oxide powder may be mixed. At this time, if the average particle size of the powder used is large, the density after sintering is not sufficiently increased, and it may be difficult to obtain a sintered body having a relative density of 99% or more. 0.5 μm or less, more preferably 0.1 to 1.5 μm
It is. Here, the mixing amount of tin oxide is Sn / (Sn +
The atomic ratio of (In) is preferably 1.9 to 14%. More preferably, it is 4 to 11%. This is because, when an ITO thin film is manufactured using the target of the present invention, the composition has the lowest resistivity of the film.

The mixing amount of magnesium oxide is Mg
2.4 to 20.0% by atomic ratio of / (In + Sn + Mg)
Is preferred. More preferably, it is 2.4 to 10.0%, further preferably, 2.4 to 5.0%, and particularly preferably, 2.4.
~ 3.0%. If the added amount of magnesium oxide is less than the above range, the effect of the present invention is weakened, the obtained thin film shows a domain structure and the weather resistance of the film is lowered, and if it exceeds the above range, the resistivity increases. Not appropriate for too much. The powder may be mixed by dry mixing or wet mixing using a ball mill or the like.

Next, a magnesium oxide-containing ITO sintered body is prepared using the obtained mixed powder. The method for producing the sintered body is not particularly limited, but it can be produced, for example, by the following method.

A binder or the like is added to the mixed powder of indium oxide, tin oxide and magnesium oxide obtained as described above, and the mixture is molded by a molding method such as a press method or a casting method to produce a molded body. When manufacturing a molded body by the press method, after filling the solid solution powder in a predetermined mold,
Pressing is performed using a powder press at a pressure of 100 to 300 kg / cm ² . If the powder has poor moldability, a binder such as paraffin or polyvinyl alcohol may be added as necessary.

When a molded article is manufactured by the casting method,
A binder, a dispersant, and ion-exchanged water are added to the TO mixed powder and mixed by a ball mill or the like to prepare a slurry for producing a cast molded body. Subsequently, casting is performed using the obtained slurry. It is preferable to defoam the slurry before pouring the slurry into the mold. For defoaming, for example, a polyalkylene glycol-based defoaming agent may be added to the slurry to perform defoaming treatment in a vacuum. Subsequently, a drying process of the cast molded body is performed.

Next, if necessary, a consolidation treatment such as a cold isostatic press (CIP) is performed on the obtained molded body. At this time, the CIP pressure is 2 ton / c to obtain a sufficient consolidation effect.
m ² or more, preferably ^{2 to 5} ton / cm ² . When the initial molding is performed by a casting method, a binder removal treatment may be performed for the purpose of removing water and organic substances such as a binder remaining in the molded body after the CIP. Even when the initial molding is performed by the press method, it is desirable to perform the same binder removal treatment when a binder is used at the time of molding.

The compact obtained in this way is put into a sintering furnace and sintered. As the sintering method, any method can be applied, but sintering in the air is desirable in consideration of the cost of production equipment and the like. However, it goes without saying that other conventionally known sintering methods such as a hot press (HP) method, a hot isostatic pressing (HIP) method and an oxygen pressure sintering method can be used. The sintering conditions can be appropriately selected, but the sintering temperature is desirably 1450 to 1650 ° C. in order to obtain a sufficient density increasing effect and to suppress the evaporation of tin oxide. The atmosphere during sintering is preferably air or a pure oxygen atmosphere. Also, the sintering time is 5 hours or more, preferably 5 to 30 to obtain a sufficient density increasing effect.
Desirably time. Thus, the magnesium-containing ITO sintered body according to the first aspect of the present invention can be manufactured.

Next, be bonded using it indium half such a backing plate made of oxygen-free copper as required The resulting magnesium sintered body was machined to a Nozomu Tokoro shape containing ITO sintered body Thereby, the magnesium-containing ITO sputtering target according to the third aspect of the present invention is manufactured.

[0028] Using the obtained scan sputtering target, it is possible to obtain a magnesium-containing ITO thin film is a transparent conductive film which is the invention of claim 3 on a glass substrate or a film substrate or the like on a substrate. The film forming means is not particularly limited, and the dc sputtering method, the rf sputtering method,
A sputtering method in which rf is superimposed on dc can be used.

The flat without a domain structure which is the first effect of the present invention, superior thin film in etching characteristic is particularly effective for a film forming method through which plasma sputtering method. The second effect, that is, stabilization of resistivity, is effective even when a film is formed by any method.

Further, indium oxide, tin oxide, 3 kinds of magnesium oxide or scan <br/> sputtering prepared as the two two-kind mixed oxides and the remaining oxides of said three, it may be a film by a multi-source co-sputtering using a target. Further, it may be used in lieu of a portion of each of the scan Pattarin <br/> grayed target or all the metal or alloy.

The thin film formed on the substrate, after being etched into a desired pattern according to need, the invention is a example a flat panel display of the claims 4, a touch panel, a solar cell window material, antistatic film, Electromagnetic wave prevention film,
Devices such as an anti-fog film and a sensor can be configured.

Further, as described above, the thin film according to the present invention comprises:
Considering use for devices that require fine processing, such as flat panel displays and touch panels,
The thickness is preferably 5000 ° or less. If the film thickness exceeds 5000 °, not only the transparency of the film is lost, but also the value of the line and space and the film thickness required at the time of the fine processing become close, and the fine processing becomes difficult. The more preferable range of the film thickness varies depending on the display used, and in the case of a resistive touch panel application, it is preferably 80 to 500 °. In the case of a display having a matrix electrode structure such as a STN type liquid crystal display, , 2000 to 3500 °.

[0033]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 450 g of indium oxide powder, 50 g of tin oxide powder and 7.2 g of magnesium oxide powder were put in a polyethylene pot and mixed by a dry ball mill for 72 hours to prepare a mixed powder.

This powder is placed in a mold and is weighed at 300 kg / cm.
Pressing was performed at a pressure of ² to obtain a molded body. 3t of this compact
Densification treatment by CIP was performed at a pressure of on / cm ² . Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the following conditions. (Sintering conditions) Sintering temperature: 1500 ° C., heating rate: 25 ° C./Hr, sintering time: 6 hours, oxygen pressure: 50 mmH ₂ O (gauge pressure),
Oxygen linear velocity: 2.7 cm / min When the density of the obtained sintered body was measured by the Archimedes method, it was 7.00 g / cm ³ (relative density: 99.2%). The composition analysis of this sintered body was performed by EPMA (Elect
ron Probe Micro Analysis)
This was performed using Table 1 shows the results.

This sintered body was processed into a sintered body having a diameter of 4 inches and a thickness of 6 mm by a wet processing method, and was bonded to a backing plate made of oxygen-free copper using indium solder to obtain a target.

This target was sputtered under the following sputtering conditions to evaluate the thin film. (Sputtering conditions) Substrate: glass substrate, DC power: 200 W, gas pressure: 5.
0 mTorr, Ar gas flow rate: 50 SCCM, O ₂ gas flow rate: 0.1 SCCM, substrate temperature: 200 ° C., film thickness: 3
000Å.

The resistivity of the obtained film is 790 μΩ · cm
The transmittance at 550 nm was 86.2%.
The transmittance was measured as a transmittance including a glass substrate using air as a reference. Cor on the glass substrate
# 7059 manufactured by Ning Co. was used.

Next, the surface of the obtained thin film was observed using AFM. The results are shown in the photograph of FIG. No domain structure was observed.

Next, the composition of the film was examined using EPMA. Table 2 shows the results.

Example 2 450 g of indium oxide powder, 50 g of tin oxide powder and 15 g of magnesium oxide powder were placed in a polyethylene pot and mixed by a dry ball mill for 72 hours to prepare a mixed powder.

This powder was placed in a mold and was weighed at 300 kg / cm.
Pressing was performed at a pressure of ² to obtain a molded body. 3t of this compact
Densification treatment by CIP was performed at a pressure of on / cm ² . Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the same conditions as in Example 1.

When the density of the obtained sintered body was measured by the Archimedes method, it was 6.86 g / cm ³ (relative density: 9).
8.6%). The composition analysis of this sintered body was performed using EPMA.
This was performed using Table 1 shows the results.

This sintered body was processed into a sintered body having a diameter of 4 inches and a thickness of 6 mm by a wet processing method, and was bonded to a backing plate made of oxygen-free copper using indium solder to obtain a target.

The thin film was evaluated by sputtering this target under the following sputtering conditions. (Sputtering conditions) Substrate: glass substrate, DC power: 200 W, gas pressure: 5.
0 mTorr, Ar gas flow rate: 50 SCCM, O ₂ gas flow rate: 0.1 SCCM, substrate temperature: 200 ° C., film thickness: 3
000Å.

The resistivity of the obtained film is 1800 μΩ · c
m, the transmission at 550 nm was 85.9%. The measurement conditions of the transmittance were the same as those in Example 1.

Next, the surface of the obtained thin film was observed using AFM. The results are shown in the photograph of FIG. No domain structure was observed.

Next, the composition of the film was examined using EPMA. Table 2 shows the results.

Example 3 450 g of indium oxide powder, 50 g of tin oxide powder and 34 g of magnesium oxide powder were placed in a polyethylene pot and mixed by a dry ball mill for 72 hours to prepare a mixed powder.

This powder is placed in a mold and is weighed at 300 kg / cm.
Pressing was performed at a pressure of ² to obtain a molded body. 3t of this compact
Densification treatment by CIP was performed at a pressure of on / cm ² . Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the same conditions as in Example 1.

The density of the obtained sintered body was measured by the Archimedes method and found to be 6.65 g / cm ³ (relative density: 9).
8.7%). The composition analysis of this sintered body was performed using EPMA.
This was performed using Table 1 shows the results.

The sintered body was processed into a sintered body having a diameter of 4 inches and a thickness of 6 mm by a wet processing method, and was bonded to a backing plate made of oxygen-free copper using indium solder to obtain a target.

The thin film was evaluated by sputtering this target under the following sputtering conditions. (Sputtering conditions) Substrate: glass substrate, DC power: 200 W, gas pressure: 5.
0 mTorr, Ar gas flow rate: 50 SCCM, O ₂ gas flow rate: 0.1 SCCM, substrate temperature: 200 ° C., film thickness: 3
000Å.

The resistivity of the obtained film was 3500 μΩ · c
m, the transmission at 550 nm was 85.9%. The measurement conditions of the transmittance were the same as those in Example 1.

Next, the surface of the obtained thin film was observed using AFM. The results are shown in the photograph of FIG. No domain structure was observed.

Next, the composition of the film was examined using EPMA. Table 2 shows the results.

Comparative Example 1 450 g of indium oxide powder and 50 g of tin oxide powder
Was placed in a polyethylene pot and mixed for 72 hours by a dry ball mill to prepare a mixed powder.

This powder is placed in a mold and is weighed at 300 kg / cm.
Pressing was performed at a pressure of ² to obtain a molded body. 3t of this compact
Densification treatment by CIP was performed at a pressure of on / cm ² . Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the same conditions as in Example 1.

The density of the obtained sintered body was measured by the Archimedes method to find that it was 7.12 g / cm ³ (relative density: 9).
9.4%). The composition analysis of this sintered body was performed using EPMA.
This was performed using Table 1 shows the results.

This sintered body was processed into a sintered body having a diameter of 4 inches and a thickness of 6 mm by a wet processing method, and was bonded to a backing plate made of oxygen-free copper using indium solder to obtain a target.

The thin film was evaluated by sputtering this target under the following sputtering conditions. (Sputtering conditions) Substrate: glass substrate, DC power: 200 W, gas pressure: 5.
0 mTorr, Ar gas flow rate: 50 SCCM, O ₂ gas flow rate: 0.1 SCCM, substrate temperature: 200 ° C., film thickness: 3
000Å.

The resistivity of the obtained film is 200 μΩ · cm
The transmittance at 550 nm was 86.7%.
The measurement conditions of the transmittance were the same as those in Example 1.

Next, the surface of the obtained thin film was observed using AFM. The results are shown in the photograph of FIG. A domain structure was observed.

Next, the composition of the film was examined using EPMA. Table 2 shows the results.

Example 4 450 g of indium oxide powder, 50 g of tin oxide powder and 3.6 g of magnesium oxide powder were put into a polyethylene pot and mixed by a dry ball mill for 72 hours to prepare a mixed powder. Put this powder in a mold, 300kg
/ Cm ² to obtain a molded body. This compact was subjected to a densification treatment by CIP at a pressure of 3 ton / cm ² . Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the same conditions as in Example 1. When the density of the obtained sintered body was measured by the Archimedes method, it was 7.09.
g / cm ³ (relative density: 99.7%). The composition of this sintered body was analyzed using EPMA. Table 1 shows the results
Shown in

This sintered body was processed into a sintered body having a diameter of 4 inches and a thickness of 6 mm by a wet processing method, and was bonded to a backing plate made of oxygen-free copper using indium solder to obtain a target.

The thin film was evaluated by sputtering this target under the following sputtering conditions. (Sputtering conditions) Substrate: glass substrate, DC power: 200 W, gas pressure: 5.
0 mTorr, Ar gas flow rate: 50 SCCM, O ₂ gas flow rate: 0.1 SCCM, substrate temperature: 300 ° C., film thickness: 1
20Å.

Next, the composition of the film was examined using EPMA. Table 2 shows the results.

A heat resistance test was performed on the obtained thin film under the following conditions, and the rate of change in resistivity was examined. The rate of change (%) is (resistivity after test−resistivity before test) × 10.
0 / The resistivity was determined before the test. (Heat resistance test conditions) Atmosphere: In the air, Temperature: 100 to 250 ° C, Holding time:
30 minutes The results are shown in FIG. At any temperature from 100 to 250 ° C., the resistivity hardly changed.

Next, the thin film obtained in the same manner was subjected to a moisture resistance test under the following conditions to examine the rate of change in resistivity. The rate of change (%) was determined by (resistivity after test-resistivity before test) × 100 / resistivity before test. (Moisture resistance test conditions) Temperature: 60 ° C., Humidity: 90% RH, Holding time: 500 hours The results are shown in FIG. Even after the elapse of 500 hours, the resistivity was stable with almost no change.

Example 5 Using a target manufactured under the same conditions as in Example 1, a film was formed under the same sputtering conditions as in Example 4, and a heat resistance test and a humidity resistance test were performed under the same conditions as in Example 4. Carried out. FIG. 7 shows the results of the heat resistance test. 100-250
At any temperature of ° C., the resistivity changed little.

FIG. 8 shows the results of the moisture resistance test. Even after the elapse of 500 hours, the resistivity was stable with almost no change.

Comparative Example 2 Using a target manufactured under the same conditions as in Comparative Example 1, a film was formed under the same sputtering conditions as in Example 4, and a heat resistance test and a moisture resistance test were performed under the same conditions as in Example 4. Carried out. FIG. 7 shows the results of the heat resistance test. 200-250
About 5% at 200 ° C, 250%
At 24 ° C., an increase in resistivity of about 24% was observed. The heat treatment at high temperature increased the resistivity significantly.

FIG. 8 shows the results of the moisture resistance test. After 300 hours, the resistivity increased, and after 500 hours, an increase in resistivity by as much as 80% was observed.

Comparative Example 3 450 g of indium oxide powder, 50 g of tin oxide powder and 1.8 g of magnesium oxide powder were placed in a polyethylene pot and mixed by a dry ball mill for 72 hours to prepare a mixed powder.

This powder was placed in a mold, and 300 kg / cm
Pressing was performed at a pressure of ² to obtain a molded body. 3t of this compact
Densification treatment by CIP was performed at a pressure of on / cm ² . Next, this compact was placed in a pure oxygen atmosphere sintering furnace and sintered under the following conditions. (Sintering conditions) Sintering temperature: 1500 ° C., heating rate: 25 ° C./Hr, sintering time: 6 hours, oxygen pressure: 50 mmH ₂ O (gauge pressure),
Oxygen linear velocity: 2.7 cm / min When the density of the obtained sintered body was measured by the Archimedes method, it was 7.12 g / cm ³ (relative density: 99.9%). The composition of this sintered body was analyzed using EPMA. Table 1 shows the results.

This sintered body was processed into a sintered body having a diameter of 4 inches and a thickness of 6 mm by a wet processing method, and was bonded to a backing plate made of oxygen-free copper using indium solder to obtain a target.

The thin film was evaluated by sputtering this target under the following sputtering conditions. (Sputtering conditions) Substrate: glass substrate, DC power: 200 W, gas pressure: 5.
0 mTorr, Ar gas flow rate: 50 SCCM, O ₂ gas flow rate: 0.1 SCCM, substrate temperature: 200 ° C., film thickness: 3
000Å.

The resistivity of the obtained film was 210 μΩ · cm
The transmittance at 550 nm was 86.6%.
Next, the surface of the obtained thin film was observed using AFM. The results are shown in the photograph of FIG. No domain structure was observed.

Next, the composition of the film was examined using EPMA. Table 2 shows the results.

Next, a heat resistance test and a moisture resistance test were performed under the same conditions as in Example 4. FIG. 7 shows the results of the heat resistance test.
By performing the heat treatment at 200-250 ° C., an increase in resistivity of about 2% at 200 ° C. and about 10% at 250 ° C. was observed. The heat treatment at high temperature increased the resistivity significantly.

FIG. 8 shows the results of the moisture resistance test. After 300 hours, the resistivity increased, and after 500 hours, an increase in resistivity by as much as 45% was observed.

Example 6 Using the target obtained in Example 4, an ITO thin film was formed on a polycarbonate substrate. (Sputtering conditions) Substrate: polycarbonate, DC power: 200 W, gas pressure: 5.0 mTorr, Ar gas flow rate: 50 SCCM,
O ₂ gas flow rate: 0.25 SCCM, substrate temperature: 70 ° C.
Film thickness: 120 °.

The composition analysis of the obtained thin film was performed by using EPMA. Table 2 shows the results.

Next, a heat resistance test was performed on the obtained thin film under the following conditions, and the rate of change in resistivity was examined. (Heat resistance test conditions) Atmosphere: in the air, temperature: 80 ° C., holding time: 90 minutes The rate of change in resistivity was + 15%.

Next, the thin film obtained in the same manner was subjected to a moisture resistance test under the same conditions as in Example 4, and the rate of change in resistivity was examined. The results are shown in FIG. Even after the elapse of 500 hours, the resistivity was stable with almost no change.

Example 7 Using the target obtained in Example 1, an ITO thin film was formed on a polycarbonate substrate under the same conditions as in Example 6.

The composition of the obtained thin film was analyzed using EPMA. Table 2 shows the results.

Next, a heat resistance test was performed on the obtained thin film under the same conditions as in Example 6 to examine the rate of change in resistivity. The rate of change of the resistivity was + 11%.

Next, the thin film obtained in the same manner was subjected to a moisture resistance test under the same conditions as in Example 6, and the rate of change in resistivity was examined. The results are shown in FIG. Even after the elapse of 500 hours, the resistivity was stable with almost no change.

Comparative Example 4 Using the target obtained in Comparative Example 1, an ITO thin film was formed on a polycarbonate substrate under the same conditions as in Example 6.

The composition of the obtained thin film was analyzed using EPMA. Table 2 shows the results.

Next, a heat resistance test was performed on the obtained thin film under the same conditions as in Example 6 to examine the rate of change in resistivity. The rate of change in resistivity showed a large value of + 45%.

Next, the thin film obtained in the same manner was subjected to a moisture resistance test under the same conditions as in Example 6 to examine the rate of change in resistivity. The results are shown in FIG. After 300 hours, the resistivity increased, and after 500 hours, a 100% increase in resistivity was observed.

Example 8 Using the target obtained in Example 1, an ITO thin film was formed on a glass substrate under the same conditions as in Example 1 to a thickness of 5000 mm.
Was prepared.

The transmittance of the obtained thin film was measured. Measurement wavelengths are 400, 500, 550, 600, 700, 80
It was set to 0 nm, and the transmittance was measured only for the film using the same glass substrate as a reference. Table 3 shows the results. Over 80% transmittance was obtained over all wavelengths.

[0097]

[Table 1]

[0098]

[Table 2]

[0099]

[Table 3]

[0100]

Application of claim 1 of the invention is a magnesium oxide-containing ITO sintered body according to the present invention, the Ah Rui sputtering target is a second aspect of the present invention, magnesium oxide-containing ITO thin film having excellent characteristics as a material Can be manufactured. That is, since a flat film is obtained without having a domain structure peculiar to the ITO thin film, it is possible to obtain the thin film according to the third aspect of the present invention which is hard to generate an etching residue and excellent in fine processing. Further, even when used in a thin film region such as a touch panel, a transparent conductive film having a small rate of change in resistivity can be obtained.

According to the fourth aspect of the present invention, the ITO
Various devices having excellent characteristics using a thin film can be configured.

Further, according to the invention of claim 5 , it is possible to provide a thin film having excellent film transparency and fine workability.

[0103] Further, according to the inventions, excellent stability of the discharge, it is possible to provide a small sputtering targets of nodules generation amount.

[Brief description of the drawings]

FIG. 1 is a diagram showing a domain structure of a conventional ITO thin film.

FIG. 2 is a view showing the surface of a conventional ITO thin film.

FIG. 3 is a view showing the surface of a thin film obtained in Example 1.

FIG. 4 is a view showing the surface of a thin film obtained in Example 2.

FIG. 5 is a diagram showing the surface of a thin film obtained in Example 3.

FIG. 6 is a view showing the surface of a thin film obtained in Comparative Example 1.

FIG. 7 is a view showing the results of a heat resistance test of the films obtained in Examples 4 and 5 and Comparative Examples 2 and 3.

FIG. 8 is a diagram showing the results of a moisture resistance test of the films obtained in Examples 4 and 5 and Comparative Examples 2 and 3.

FIG. 9 is a view showing the surface of a thin film obtained in Comparative Example 3.

FIG. 10 is a view showing the results of a moisture resistance test of the films obtained in Examples 6, 7 and Comparative Example 4.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideyuki Shinoda 2-1-1 Minatomirai, Nishi-ku, Yokohama-shi, Kanagawa Prefecture Within Geomatic Tech Co., Ltd. (72) Inventor Kentaro Utsumi 5-7-8 Chuo-Rinma, Yamato-shi, Kanagawa Prefecture (72) ) Inventor Yuichi Nagasaki 5-21-33 Rokkakubashi, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture (72) Inventor Tsutomu Takahata 1-4-5, Akanedai, Aoba-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP-A-8-264022 (JP) , A) JP-A-6-349338 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 35/00-35/51 C23C 14/24, 14/34 H01B 1/08 , 5/14

Claims (5)

(57) [Claims] 1. The method according to claim 1, wherein said magnesium is substantially composed of indium, tin, magnesium and oxygen.
A metal oxide sintered body characterized in that it is contained at a ratio of 2.4 to 20.0% in an atomic ratio of (Sn + Mg) and has a relative density of 98% or more . 2. Substantially consisting of indium, tin, magnesium and oxygen, wherein magnesium is Mg / (In +
A metal oxide sintered body characterized in that it is contained at a ratio of 2.4 to 20.0% in an atomic ratio of (Sn + Mg) and has a relative density of 98% or more . Sputtering target. 3. Substantially consisting of indium, tin, magnesium and oxygen, wherein magnesium is Mg / (In +
A transparent conductive film, which is contained at a ratio of 2.4 to 20.0% in an atomic ratio of (Sn + Mg). 4. An apparatus comprising the transparent conductive film according to claim 3 . 5. The transparent conductive film according to claim 3, wherein the thickness of the film is 5000 ° or less.