HK1050720B

HK1050720B - Sputtering target, transparent conductive oxide, and method for preparing sputtering target

Info

Publication number: HK1050720B
Application number: HK03102914.6A
Authority: HK
Inventors: 井上一吉; 谷忠夫; 海上晓
Original assignee: 出光兴产株式会社
Priority date: 1999-11-25
Filing date: 2000-11-22
Publication date: 2005-09-30

Description

Sputtering target, transparent conductive oxide and method for producing the sputtering target

Technical Field

The present invention relates to a sputtering target (hereinafter simply referred to as target), a transparent conductive oxide made of the sputtering target, and a method for producing the sputtering target.

In particular, the present invention relates to a target capable of suppressing spherical objects generated when a transparent conductive oxide is formed into a thin film by sputtering and making sputtering more stable, a transparent conductive oxide made from such a target, and a method for producing the target.

Background

In recent years, display devices have been remarkably developed. Liquid crystal display devices (LCDs), electroluminescent display devices (ELs), Field Emission Displays (FEDs), and the like have been used as display devices for office machines such as personal computers and data processors or for control systems in factories. These display devices have a sandwich structure in which display elements are sandwiched between transparent conductive oxides.

As in document 1: as disclosed in "transparent Conductive Film Technology" (Technology on transparent Conductive Film "published by Ohmsha ltd, 166 th day the society for promotion of science on the related to the committee on transparent oxides and optoelectronic materials), indium-tin oxide (hereinafter, abbreviated as ITO) which forms a Film by sputtering, ion plating method or vapor deposition is mainly used as such a transparent Conductive oxide.

The ITO is composed of indium oxide and tin oxide in given amounts, and is characterized by excellent transparency and conductivity, ability to be etched with a strong acid, and good adhesion to a substrate.

Meanwhile, JP-A-3-50148, JP-A-5-155651, JP-A-5-70943, JP-A-6-234565 and the like disclose targets made of given amounts of indium oxide, tin oxide and zinc oxide, or transparent electrodes (hereinafter abbreviated as IZO) made of thin films formed of such targets. These can be etched with a weak acid and are widely used because they have good sinterability and transparency.

As described above, ITO or IZO has excellent performance as a transparent conductive oxide material, but there is a problem that when a target is used to form ITO or IZO into a thin film, the spherical objects (protrusions) shown in fig. 2 (photograph) are easily generated on the surface of the target.

Particularly when an amorphous ITO thin film is formed to improve etching performance, there arises a problem that the surface of the target is reduced due to the addition of a very small amount of water or hydrogen gas in the sputtering chamber for setting, and thus, it is more likely to generate a ball.

When such a sphere is generated on the surface of the target, the sphere is easily scattered due to the energy of plasma during sputtering. As a result, there arises a problem that discrete substances as foreign substances adhere to the transparent conductive oxide during the film formation or immediately after the film formation.

The generation of the spherical objects on the target surface is one of the causes of abnormal discharge.

Therefore, ｃA measure for suppressing the generation of nodules in the target is disclosed in JP-A-8-283934, which attempts to make the target material denser by sintering at high temperature to reduce the porosity. That is, a target whose density was 99% of the theoretical density was prepared, but the spherical object could not be completely removed even in this case.

Under such circumstances, it is desired to develop a target which can suppress generation of a spherical object and make sputtering more stable when a thin film is formed by sputtering.

Accordingly, the present inventors have earnestly conducted extensive studies in order to solve the above problems. As a result, the present inventors have found that the spherical objects produced on the surface of the target are substantially remnants of the sink, and the reason for producing the sink remnants depends on the grain size (e.g., 10 μm or more) of the metal oxide constituting the target.

In other words, when the target is struck on its surface by sputtering, the speed of striking differs depending on the orientation of the crystal plane, so unevenness is generated on the surface of the target. It has been demonstrated that the magnitude of the unevenness depends on the grain size of the metal oxide present in the sintered body.

Therefore, it is considered that when a target made of a sintered body having a large crystal grain diameter is used, the unevenness generated in the target surface gradually increases, so that a spherical object is formed from the uneven convex portion.

An object of the present invention is to provide a target which can suppress generation of a spherical object and make sputtering more stable when a transparent conductive oxide is formed into a thin film by sputtering, a transparent conductive oxide made of the target, and a method for producing the target.

Disclosure of Invention

According to the present invention, there is provided a sputtering target comprising at least indium oxide and zinc oxide, wherein the atomic ratio expressed by In/(In + Zn) is set to 0.75 to 0.97, including by In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20), and the crystal grain diameter of the hexagonal layered compound is 5 μm or less.

That is, the size of the unevenness generated on the target surface is controlled by limiting the grain size value to the above range, so that the formation of the spherical object can be effectively suppressed.

When the sputtering target of the present invention is prepared, it preferably comprises 67 to 93% by weight of indium oxide, 5 to 25% by weight of tin oxide, and 2 to 8% by weight of zinc oxide, and the atomic ratio of tin to zinc is 1 or more.

Such a composition makes the target denser and can more effectively suppress the generation of spherical objects.

In this manner, by setting the atomic ratio of tin to zinc to 1 or higher, the resistivity after crystallization is effectively lowered, so that a transparent conductive oxide having excellent conductivity can be obtained.

When preparing the sputtering target of the present invention, it is preferable to include Zn₂SnO₄The spinel-structured compound is shown in place of the hexagonal layered compound or includes the spinel-structured compound and the hexagonal layered compound, and the grain diameter of the spinel-structured compound is set to 5 μm or less.

Such a composition makes the target denser, thereby more effectively suppressing the generation of spherical objects.

Such a composition can also form a transparent conductive oxide having excellent transparency and conductivity by sputtering.

When the sputtering target of the present invention is prepared, it is preferable to set the volume resistivity thereof to less than 1X 10^-3Ω·cm。

Such a composition can reduce abnormal discharge (spark) during sputtering and stably form a sputtered film. On the contrary, if the volume resistivity is 1X 10^-3Omega cm or more, and the current is concentrated on the surface of the target, whichThe sample is more prone to abnormal discharge.

When the sputtering target of the present invention is produced, it is preferable to set the density to 6.7g/cm³Or higher.

Such a composition can achieve excellent mechanical properties and make the target denser, thus more effectively suppressing the generation of spherical objects.

Another aspect of the present invention is a transparent conductive oxide (amorphous transparent conductive oxide) containing a sputtering target, wherein the atomic ratio represented by In/(In + Zn) is set to 0.75 to 0.97, including by In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20), and the crystal grain diameter of the hexagonal layered compound is set to 5 μm or less.

Such a composition can effectively produce an amorphous transparent conductive oxide excellent in transparency and conductivity.

When the transparent conductive oxide of the present invention is prepared, it is preferable that 67 to 93% by weight of indium oxide, 5 to 25% by weight of tin oxide, and 2 to 8% by weight of zinc oxide are included in the sputtering target, and the atomic ratio of tin to zinc is 1 or more.

The transparent conductive oxide of the present invention is preferably crystallized at a temperature of 230 c or more.

Such a composition can effectively produce an amorphous transparent conductive oxide that is better in transparency and conductivity.

Even if the oxide is formed on the substrate, the possibility that the substrate is broken at such a temperature becomes small.

When the transparent conductive oxide of the present invention is prepared, it is preferable to set the half-peak width of the binding energy peak of the oxygen 1S orbital determined by X-ray photoelectron spectroscopy (XPS) to 3eV or less.

When the transparent conductive oxide of the present invention is prepared, it is preferable that the transparent conductive oxide is formed on a substrate or on a colored layer provided on the substrate.

The composition can effectively provide a transparent electrode and a transparent electrode having a color filter layer.

When the transparent conductive oxide of the present invention is prepared, its P-V value is preferably set to 1 μm or less in accordance with JIS B0601.

If such a composition is used as a transparent electrode, a transparent electrode with a color filter layer, or the like, the occurrence of a snap-off or short-circuit of the wiring can be effectively prevented.

Yet another aspect of the invention is a method of making a sputtering target, wherein said sputtering target comprises In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20) of a hexagonal layered compound whose crystal grain diameter is set to 5 μm or less, the method comprising steps (1) to (3) (hereinafter, this method is referred to as a first production method):

(1) mixing indium oxide powder and zinc oxide powder having an average particle size of less than 2 microns or less,

(2) forming a shaped body In which the atomic ratio of In/(In + Zn) is from 0.75 to 0.97, and

(3) the shaped body is sintered at a temperature of 1400 ℃ or higher.

When the production method is carried out in this way, it is possible to effectively provide a target which can suppress the generation of nodules when the transparent conductive oxide is formed into a thin film by sputtering and can stably perform sputtering.

When the first production method of the sputtering target of the present invention is carried out, it is preferable that 67 to 93% by weight of the indium oxide powder, 5 to 25% by weight of the tin oxide powder, and 2 to 8% by weight of the zinc oxide powder are mixed in step (1), and a compact having an atomic ratio of tin to zinc of 1 or more is produced in step (2).

Yet another aspect of the invention is a method of making a sputtering target, wherein said sputtering target comprises In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20) of a hexagonal layered compound having a crystal grain diameter of 5 μm or less, the method comprising steps (1) to (5) (hereinafter, this method will be referred to as a second production method):

(1) preparation of In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20),

(2) the particle size of the prepared hexagonal layered compound is adjusted to 5 μm or less,

(3) mixing the hexagonal layered compound with the adjusted particle size with indium oxide powder,

(4) forming a shaped body In which the atomic ratio of In/(In + Zn) is from 0.75 to 0.97, and

(5) the shaped body is sintered at a temperature of 1400 ℃ or higher.

When the production method is carried out in this manner, a hexagonal layered compound whose particle size is controlled in advance may be used. Thus, it is easier to control the average particle size in the target.

When carrying out the first and second production methods of the present invention, it is preferable that the sintering step is carried out under an oxygen atmosphere or under compressed oxygen.

When the production method of the present invention is carried out in this manner, a sputtering target which better suppresses generation of spherical objects and stably performs sputtering can be effectively provided.

In carrying out the first and second production methods of the present invention, it is preferable that the average particle size of indium oxide is 0.1 to 2 μm.

When the method is carried out in this manner, a target in which the grain size of the hexagonal layered compound is controlled within a given range can be more effectively provided.

When the first and second production methods of the present invention are carried out, it is preferable that tin oxide powder is further mixed together with indium oxide powder, and the average particle size of the tin oxide powder is 0.01 to 1 μm.

When the method is carried out in this manner, it is possible to more effectively provide a target in which the grain diameters of the hexagonal layered compound and the spinel-structured compound are controlled within given ranges.

When the first and second production methods of the present invention are carried out, preferably at the time of producing a shaped body, a spinel-type compound whose particle size is adjusted to 5 μm or less is further mixed.

When the production method is carried out in this manner, a spinel-structured compound whose particle size is controlled in advance may be used. Thus, the average particle size in the target can be more easily controlled.

Brief description of the drawings

FIG. 1 is a photograph of the surface of a target (after sputtering) in the first aspect of the invention.

Fig. 2 is a photograph of the surface of a conventional target (after sputtering).

FIG. 3 is a graph showing the relationship between the grain size and the number of balls in the target of the first aspect of the present invention.

FIG. 4 is a graph showing the relationship between the grain size and the number of balls in the target according to the second aspect of the present invention.

FIG. 5 is an X-ray diffraction pattern of a target containing a hexagonal layered compound.

FIG. 6 is an X-ray diffraction pattern of a target containing a spinel-structured compound.

Fig. 7 is a graph of resistivity stability ratio of transparent conductive oxide.

Fig. 8 is a graph of light transmittance of a transparent conductive oxide.

Fig. 9 is a graph of the refractive index of a transparent conductive oxide.

Fig. 10 is a graph showing the effect of heat treatment temperature in preparing a transparent conductive oxide.

FIG. 11 shows a process for preparing a color filter layer.

Fig. 12 is a graph of the binding energy peak of the 1S orbital of oxygen in a transparent conductive oxide (No. 1).

Fig. 13 is a binding energy peak diagram (2 nd) of the 1S orbital of oxygen in the transparent conductive oxide.

Best Mode for Carrying Out The Invention

First to eighth aspects (first to sixth inventions) of the present invention are described one by one with reference to the drawings.

The drawings referred to are only schematic representations of the sizes and shapes of the respective constituent parts and the arrangement relationship therebetween to an extent that the present invention can be understood. Accordingly, the invention is not limited to the described embodiments. In the drawings, hatching for showing the cross section may be omitted.

First aspect

The first aspect is an embodiment relating to the first invention, and is a sputtering target comprising at least indium oxide and zinc oxide, wherein the atomic ratio represented by In/(In + Zn) is set to 0.75 to 0.97, and further comprising In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20),and the grain diameter of the hexagonal layered compound is set to 5 μm or less.

(1) Composition ratio

In this first aspect, it is necessary to set the atomic ratio expressed as In/(In + Zn) to 0.75 to 0.97 for the composition of each metal oxide constituting the component of the target.

This is because if the atomic ratio expressed as In/(In + Zn) is lower than 0.75, the conductivity of the transparent conductive oxide obtained by sputtering may be reduced. On the other hand, if the atomic ratio expressed as In/(In + Zn) exceeds 0.97, the In content increases, so that a spherical object is easily generated In sputtering.

Accordingly, it is more preferable to set the atomic ratio expressed as In/(In + Zn) to 0.80 to 0.95, and most preferably to 0.85 to 0.95, because the balance between the conductivity of the obtained transparent conductive oxide and the prevention of generation of nodules becomes better.

(2) Crystal structure 1

The first aspect is characterized by comprising indium oxide and zinc oxide, which are components of a target and are expressed as In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20).

The reason why indium oxide and zinc oxide cannot be present only in a mixture but are added in the form of crystals of a hexagonal layered compound is that the target can be denser or the density of the target can be improved, and the conductivity of the obtained transparent conductive oxide can be improved.

The crystal growth of indium oxide can be suppressed by allowing indium oxide and zinc oxide to be contained in the form of crystals of a hexagonal layered compound. As a result, when sputtering is performed, the formation of the spherical object is prevented to make the sputtering more stable.

Is expressed as In₂O₃(ZnO)_mThe presence of the hexagonal layered compound of (a) can be determined by X-ray diffraction analysis of the crystal structure. For example, if FIGS. 5(a) - (d) are obtained) The X-ray diffraction analysis chart shown In (1) and the peak chart thereof, then In can be resolved₂O₃(ZnO)_mThe existence of the hexagonal layered compound is shown.

(3) Crystal structure 2

Crystal particle size

In the first aspect, it is necessary to set the crystal particle size of the hexagonal layered compound in the target to 5 μm or less.

This is because if the grain size of the crystal exceeds 5 μm, a spherical object is very easily generated when sputtering is performed.

However, if the particle size of the crystals is particularly small, it may be difficult to control or the kind of raw materials that can be used is excessively limited.

Accordingly, the crystal particle size of the hexagonal layered compound in the target is more preferably 0.1 to 4 microns, most preferably 0.5 to 3 microns.

② relationship between size of crystal particle and number of spheres produced

The relationship between the grain size of the hexagonal layered compound and the number of generated spheres will be described in detail with reference to fig. 3.

The horizontal axis in fig. 3 represents the grain size (micrometers) of the hexagonal layered compound, and the vertical axis in fig. 3 represents the number of spheres (pieces/8 hours/900 square millimeters) per unit area and unit time.

As can be easily understood from fig. 3, if the grain size of the hexagonal layered compound is 5 μm or less, the number of generated spheres is 0/8 hr/900 mm square. On the other hand, if the grain size of the hexagonal layered compound exceeds 5 μm, the number of generated spheres rapidly increases, and the spheres are formed in a number of 8 to 32/8 hours per 900 square millimeters.

Conversely, as can be inferred from fig. 3, it is effective to set the grain size of the hexagonal layered compound to 5 μm or less in order to effectively prevent the generation of the spherical objects, and the formation of the spherical objects can be certainly prevented by setting the grain size to 4 μm or less.

Method for measuring grain size

The grain size of the hexagonal layered compound was measured using an electron beam microanalyzer (hereinafter abbreviated as EPMA).

More specifically, after polishing the surface of the target to a smooth surface, the surface of the target was enlarged by 5,000 times using a microscope. In this case, a 30 μm x 30 μm frame was placed at an arbitrary position, and then the maximum grain size in the hexagonal layered compound found in the frame was measured using EPMA. At 3 or more locations, the maximum size of the grains within the frame is determined. Their average value is calculated. This value is defined as the grain size of the hexagonal layered compound.

The grain size of the hexagonal layered compound can be easily distinguished by plotting zinc (concentration distribution) using EMPA, and thus the size of the grains can be actually measured.

Control of grain size

The grain size of the hexagonal layered compound can be controlled within a given range by appropriately changing the selection of the kind of powdery component constituting the target, the average particle size of the powdery component, the conditions for producing the target, and the like.

For example, with respect to the kind and average particle size of the powdery component, it is recommended that the average particle size of zinc oxide used in preparing the target be 2 μm or less.

This is because if the average particle size of zinc oxide exceeds 2 μm, zinc oxide tends to diffuse and migrate to indium oxide, making it difficult to control the grain size of the hexagonal layered compound formed.

Conversely, if the average particle size of the zinc oxide powder is 2 μm or less, indium oxide is liable to diffuse and migrate to zinc oxide, so that the grain size of the hexagonal layered compound can be controlled to 5 μm or less.

However, if the average particle size of the zinc oxide powder becomes very small, its handling may become more difficult. In addition, mixing and pulverization treatment become necessary, resulting in an increase in cost.

Thus, the average particle size of the zinc oxide powder is preferably from 0.1 to 1.8 microns, more preferably from 0.3 to 1.5 microns, most preferably from 0.5 to 1.2 microns.

On the other hand, it is preferable that the average particle size of the indium oxide also be substantially equal to the average particle size of the zinc oxide powder.

Therefore, the average particle size of the indium oxide powder used in preparing the target is preferably 0.1 to 1.8 micrometers, more preferably 0.3 to 1.5 micrometers, and most preferably 0.5 to 1.2 micrometers.

(4) Volume resistivity

The volume resistivity of the target is preferably less than 1X 10^-3Ω·cm.

This is because if the volume resistivity is 1X 10^-3Ω · cm or more, abnormal discharge is generated during sputtering, and thus a sphere is formed on the target surface.

However, if the volume resistivity is less than 0.5X 10^-3Ω · cm, the properties of the obtained film may be crystalline.

Therefore, the volume resistivity of the target is more preferably 0.5X 10^-3Omega cm to 0.9X 10^-3Omega cm, most preferably 0.6X 10^-3Omega cm to 0.8X 10^-3Ω·cm。

(5) Density of

The density of the target is preferably 6.7g/cm³Or higher.

This is because if the density is less than 6.7g/cm³Then the number of balls produced may increase.

However, if the density exceeds 7.1g/cm³Then, the target itself becomes metallic, so that sputtering cannot be stably performed. As a result, a film having excellent conductivity and transparency cannot be obtained.

[ second aspect of the invention ]

The second aspect is an embodiment concerning the second invention, and is a sputtering target of the first aspect, which comprises 67 to 93% by weight of indium oxide, 5 to 25% by weight of tin oxide, and 2 to 8% by weight of zinc oxide, and the atomic ratio of tin to zinc is 1 or more.

(1) Composition ratio

First, indium oxide

In the second aspect, the composition of each metal oxide constituting the composition of the target is characterized in that the percentage content of indium oxide is 67 to 93% by weight.

This is because if the content of indium oxide is less than 67% by weight, crystallization by heat treatment is difficult, and the conductivity of the transparent conductive oxide thus obtained will decrease. On the other hand, if the content of indium oxide exceeds 93 wt%, crystallization is liable to advance conversely, so that the film characteristics after sputtering may become crystalline immediately.

Therefore, the indium oxide content is more preferably 80 to 93% by weight, and still more preferably 74 to 93% by weight, because the balance between the transparent conductive oxide and its crystallinity becomes better.

② tin oxide

The percentage content of tin oxide in the target is 5 to 25% by weight.

This is because if the content of tin oxide is less than 5% by weight, the conductivity cannot be improved even if the crystallization is advanced by the heat treatment. Whereas the conductivity of the obtained transparent conductive oxide is decreased.

On the other hand, if the content of tin oxide exceeds 25% by weight, the transparent conductive film cannot be crystallized even by heat treatment, so that the conductivity is lowered and the formation of spheres is more facilitated.

Therefore, the tin oxide content is more preferably 5 to 20% by weight, most preferably 7 to 15% by weight, because the crystallinity and conductivity of the transparent conductive oxide plus prevention of spheroid generation becomes better.

(iii) Zinc oxide

The percentage content of zinc oxide in the target is 2 to 8% by weight.

This is because if the content of zinc oxide is less than 2 wt%, the transparent conductive oxide obtained in sputtering is more likely to be crystallized. In addition, the grain size of the target is increased, which makes it easier to form spheres during sputtering.

On the other hand, if the content of zinc oxide exceeds 8 wt%, the transparent conductive oxide cannot be crystallized even by heat treatment, so that the conductivity of the transparent conductive oxide cannot be improved. If the content of zinc oxide exceeds 8 wt%, the volume resistivity of the target may exceed 1X 10^-3Ω · cm, stable sputtering cannot be obtained.

Therefore, the zinc oxide content is more preferably 2 to 6% by weight, most preferably 3 to 5% by weight, because the conductivity of the obtained transparent conductive oxide plus the volume resistivity of the target and the prevention of the spheroid production property become better.

Tin/zinc

Preferably, the atomic ratio of tin to all metal atoms is substantially equal to or higher than the atomic ratio of zinc to all metal atoms. Specifically, the atomic ratio of tin to zinc is preferably 1 or higher.

This is because if the atomic ratio of tin to zinc is below 1, the diffusion and movement of tin is reduced even under heat treatment, so that the so-called doping effect becomes lower. As a result, the conductivity of the obtained transparent conductive oxide may be reduced.

However, if the atomic ratio of tin to zinc is very large, unreacted tin remains as an ionic impurity, and thus conductivity is lowered due to so-called ionic impurity diffusion.

Thus, the atomic ratio of tin to zinc is preferably from 2 to 10, most preferably from 3 to 5.

The weight percentage of tin atoms to zinc atoms

The weight percentage of tin atoms to all metal atoms (Sn/(In + Sn + Zn) × 100) is preferably at least 3% higher than the weight percentage of zinc atoms to all metal atoms (Zn/(In + Sn + Zn) × 100).

This is because if the difference (%) between the two percentages is more than 3%, the tin doping effect based on the heat treatment can be effectively obtained. Therefore, the conductivity of the obtained transparent conductive oxide can be improved.

However, if the difference (%) between these two percentages is very large, the conductivity is lowered due to the diffusion of the above-mentioned ionic impurities.

Therefore, the ratio between the weight percentages of tin atoms and zinc atoms is more preferably from 4 to 30%, most preferably from 5 to 20%.

(2) Crystal structure 1

In the same manner as In the first aspect of the present invention, the target of the second aspect of the present invention is comprised of₂O₃(ZnO)_mIndium oxide and zinc oxide of hexagonal layered compounds represented by (wherein m is a positive integer of 2 to 20).

(3) Crystal structure 2

Compound with spinel structure

The crystal structure of the second aspect of the present invention is characterized by including Zn in the target₂SnO₄A spinel-structured compound represented by (a) in place of the hexagonal layered compound or comprising the spinel-structured compound and hexagonal layered compoundThe cubic lamellar compound, and the crystal grain diameter of the spinel-structured compound is set to 5 μm or less.

This is because the tin oxide and the zinc oxide are converted into Zn₂SnO₄The presence of the crystal form of the indicated spinel-structured compound makes it possible to make the density of the target higher and to improve its conductivity. Accordingly, by using such a target, a further improvement in stability can be obtained when sputtering is performed.

By adding these hexagonal layered compounds and spinel structure compounds, the growth of indium oxide crystals can be suppressed, so that the entire sputtering target becomes a finer and dense crystal structure. The conductivity of the obtained transparent conductive oxide can also be improved.

X-ray diffraction analysis

From Zn₂SnO₄The presence of the indicated spinel-structured compound can be determined by X-ray diffraction analysis of the crystal structure.

For example, if X-ray diffraction analysis charts and peak charts thereof shown in FIGS. 6(a) to (d) are obtained, Zn can be discriminated₂SnO₄The presence of the indicated spinel-structured compound.

③ crystal grain size

The crystal particle size of the spinel-structured compound is preferably 5 μm or less. This is because if the grain size of the crystal exceeds 5 μm, a spherical object is very easily generated in sputtering.

However, if the particle size of the crystal is particularly small, it may be difficult to control or the kind of raw materials that can be used is excessively limited.

Accordingly, the grain size of the spinel-structured compound in the target is more preferably 0.1 to 4 micrometers, most preferably 0.5 to 3 micrometers.

As described in the first aspect of the present invention, the crystal grain diameter of the spinel-structured compound can be easily distinguished by plotting zinc (concentration distribution) using EMPA in the same manner as for the hexagonal layered compound, and therefore the size of the crystal grain can be actually measured.

Relationship between grain size and number of spheres produced

The relationship between the grain diameters of the spinel-structured compound and the hexagonal layered compound and the number of generated spheres will be described in detail with reference to fig. 4.

The horizontal axis in fig. 4 represents the grain size (micrometers) in the presence of both the spinel-structured compound and the hexagonal layered compound, and the vertical axis in fig. 4 represents the number of formed spheres per unit area and unit sputtering time (pieces/8 hours/900 square millimeters).

As can be easily understood from fig. 4, if the grain size of the spinel-structured compound and the hexagonal layered compound is 5 μm or less, the number of generated spheres is 0/8 hours/900 square millimeters. On the other hand, if the grain diameters of the spinel-structured compound and the hexagonal layered compound exceed 5 μm, the number of generated spheres rapidly increases, and the spheres are formed in a number of 8 to 32/8 hours/900 square millimeters.

Conversely, as can be inferred from fig. 4, it is effective to set the grain size of the spinel-structured compound and the hexagonal layered compound to 5 μm or less in order to effectively prevent the generation of the spherical objects, and the formation of the spherical objects can be certainly prevented by setting the grain size to 4 μm or less.

Control of grain size

The grain size of the spinel-structured compound can be controlled within a given range by appropriately changing the selection of the kind of powdery component constituting the target, the average particle size of the powdery component, the conditions for preparing the target, and the like.

For example, regarding the kind and average particle size of the powdery component, it is preferable that the average particle size of the zinc oxide powder used in preparing the target is 2 μm or less. The average particle size of the tin oxide powder is set to 0.01 to 1 μm so that the average particle size of the tin oxide powder is smaller than that of the zinc oxide powder.

This is because if the average particle sizes of each of the zinc oxide powder and the tin oxide powder are limited to such ranges, their diffusion and movement can be controlled, so that the grain diameters of the hexagonal layered compound and the spinel-structured compound in the target are more easily controlled (5 μm or less).

Therefore, the average particle size of the tin oxide powder is more preferably 0.02 to 0.5 μm, particularly preferably 0.03 to 0.3. mu.m, and most preferably 0.05 to 0.2. mu.m. The desired target is obtained by preparing a hexagonal layered compound and a spinel-structured compound in advance, imparting the compounds with a desired particle size, and mixing them with indium oxide powder.

(4) Volume resistivity and density

In the second aspect of the present invention, as in the first aspect, the volume resistivity of the target is preferably less than 1X 10^-3Omega cm, the density is preferably 6.7g/cm³Or higher.

[ third aspect of the invention ]

The third aspect is an embodiment concerning the third invention, and is a transparent conductive oxide obtained using a sputtering target In which an atomic ratio expressed by In/(In + Zn) is set to 0.75 to 0.97, and further including In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20), and the crystal grain diameter of the hexagonal layered compound is set to 5 μm or less.

(1) Target

In the third aspect, the target used is the same as in the first aspect. Therefore, the target is a target In which the atomic ratio represented by In/(In + Zn) is 0.75 to 0.97, more preferably a target In which the atomic ratio represented by In/(In + Zn) is 0.80 to 0.95, and most preferably a target In which the atomic ratio represented by In/(In + Zn) is 0.85 to 0.95.

(2) Thickness of film

The thickness of the transparent conductive oxide thin film may be appropriately selected depending on the purpose of use, the base material on which the transparent conductive oxide is provided, and the like. Generally, the film thickness is preferably 3 to 3,000 nm.

The reason for this is as follows. If the thickness of the thin film is less than 3 nm, the conductivity of the transparent conductive oxide may be insufficient. On the other hand, if the film thickness exceeds 3,000 nm, light transmittance thereof is lowered or cracks and the like are easily generated in the transparent conductive oxide when the transparent conductive oxide is deformed during or after the step of preparing the transparent conductive oxide.

Therefore, the thickness of the transparent conductive oxide thin film is preferably 5 to 1,000 nm, more preferably 10 to 800 nm.

Fig. 7 and 8 show the effect of film thickness on the resistivity change rate and transmittance curves of the transparent conductive oxide, respectively.

As is understood from fig. 7, even though the film thickness of the transparent conductive oxide (base PET) was changed to 68 nm (curve a), 100 nm (curve B) and 200 nm (curve C), respectively, the resistivity change rate was hardly different in the 1000-hour heating test at 90 ℃.

With respect to fig. 8, in IZO, the film thickness becomes 100 nm (curve B), 220 nm (curve C) and 310 nm (curve D), respectively, and if the film thickness is made thicker, a tendency that the light transmittance is slightly lowered at the corresponding wavelength is found.

(3) Substrate

When the transparent conductive oxide is made into a thin film using the target, the thin film is preferably prepared on a substrate.

Such a substrate is preferably a glass substrate or a film-like or sheet-like substrate made of a transparent resin.

More specific examples of the glass substrate include glass plates made of soda lime glass, lead glass, borosilicate glass, high-purity silica glass, alkali-free glass, and the like.

Of these glass plates, alkali-free glass is more preferable because alkali metal ions do not diffuse into the transparent conductive oxide.

The transparent resin is preferably a resin having sufficiently high light transmittance and excellent electrical insulation. Specific examples thereof include polyester resins such as polyethylene terephthalate resins, polycarbonate resins, polyacrylate resins, polyethersulfone resins, acrylic resins, polyimide resins, polyamide resins, and maleimide resins.

Among these resins, polycarbonate resins, polyacrylic resins, polyethylene terephthalate resins, or polyether sulfone resins are suitably used because these resins also have heat resistance.

(4) Thermal treatment

In the transparent conductive oxide of the third aspect, the conductivity thereof is improved by heat treatment (including crystallization treatment) after the thin film is formed.

As for the conditions of the heat treatment, the treatment time is preferably 0.5 to 3 hours in a temperature range of 180 to 300 ℃, preferably 200 to 250 ℃.

It has been demonstrated that if such heat treatment conditions are used, the resistivity of the transparent conductive oxide immediately after the formation of the thin film is lowered, for example, in a proportion of 20 to 80%.

(5) Resistivity of

The resistivity of the transparent conductive oxide is preferably 800 μ Ω · cm or less.

If the resistivity exceeds 800. mu. omega. cm, the use thereof is very limited.

Therefore, the resistivity of the transparent conductive oxide is more preferably 600 μ Ω · cm or less, and most preferably 300 μ Ω cm or less.

(6) Light transmittance

As shown in a curve B (IZO/7059 glass) in fig. 8, the light transmittance (at a wavelength of 500 nm or 550 nm) of the transparent conductive oxide is preferably 75% or more, preferably 80% or more at a thickness of, for example, 100 nm.

If the transparent conductive oxide has such light transmittance, the transparent conductive oxide is suitable as a transparent electrode of various display devices requiring high transparency and conductivity, such as liquid crystal displays and electroluminescent displays.

Curve a in fig. 8 is a light transmittance curve of a glass substrate (7059 glass); curve C is an example of the IZO thin film of the third aspect in which the thickness formed on the glass substrate is 220 nm; curve D is an example of the IZO thin film of the third aspect in which the thickness formed on the glass substrate is 310 nm; and curve E is an example in which an ITO thin film having a thickness of 220 nm is formed on a glass substrate.

(7) Refractive index

As shown in a curve B (IZO/7059 glass) in fig. 9, the refractive index (at a wavelength of 500 nm) of the transparent conductive oxide is preferably 2.5 or less in the case where the thickness thereof is, for example, 90 nm.

If the transparent conductive oxide has such a low refractive index, the transparent conductive oxide is suitable as a transparent electrode of various display devices requiring high transparency and antireflection property, such as liquid crystal displays and electroluminescent displays.

Curve a of fig. 9 is an example of the IZO thin film of the third aspect in which the thickness is 30 nm formed on the glass substrate (7059 glass).

(8) Surface roughness (P-V value)

The P-V value (according to JIS B0601) of the transparent conductive oxide, which is an index for the surface roughness of the transparent conductive oxide, is preferably 1 μm or less.

If the transparent conductive oxide has such a P-V value, the connection line can be effectively prevented from being abruptly broken or short-circuited even if the transparent conductive oxide is used as a transparent electrode of various display devices such as a liquid crystal display and an electroluminescent display.

In the case where the surface roughness of the transparent conductive oxide is represented by other indices, the Ra (according to JIS B0601) thereof is preferably 100 nm or less and Rz (according to JIS B0601) thereof is preferably 500 nm or less.

(9) Method for forming thin film

When the transparent conductive oxide is formed into a thin film on the substrate, the following means may be used: a magnetron sputtering machine, an electron beam machine, an ion plating machine, a laser ablation machine, etc. More preferably, a magnetron type sputtering machine is used.

Regarding the conditions for producing a thin film using, for example, a magnetron type sputtering machine or the like, the plasma output varies somewhat depending on the area of the target or the film thickness of the transparent conductive oxide. However, it is generally preferable to set the plasma output to 0.3 to 4W/cm²The target area and the film formation rate were 5 to 120 minutes.

(10) Use of

Examples of preferred uses of the third aspect include transparent electrodes of liquid crystal displays, transparent electrodes of electroluminescent displays, transparent electrodes of solar cells, raw materials when these transparent electrodes are produced by etching, antistatic films, and freeze-proof heaters for glazing.

[ fourth aspect ]

The fourth aspect is an embodiment concerning a fourth invention, which is a transparent conductive oxide obtained using the sputtering target of the third aspect, and comprises 67 to 93% by weight of indium oxide, 5 to 25% by weight of tin oxide, and 2 to 8% by weight of zinc oxide, the atomic ratio of tin to zinc being 1 or higher.

(1) Target

As the target of the fourth aspect, the same target as in the second aspect may be used.

That is, the target is a target comprising 67 to 93 wt% indium oxide, 5 to 25 wt% tin oxide, and 2 to 8 wt% zinc oxide.

As the composition of the target, it is more preferable to include 74 to 93% by weight of indium oxide, 5 to 20% by weight of tin oxide, and 2 to 6% by weight of zinc oxide. Most preferably from 80 to 89 weight percent indium oxide, from 8 to 15 weight percent tin oxide and from 3 to 5 weight percent zinc oxide.

In the target used in the fourth aspect, as in the second aspect, the atomic ratio of tin atoms to all metal atoms in the component tin oxide of the transparent conductive oxide is equal to or higher than the atomic ratio of zinc atoms to all metal atoms in the zinc oxide. In short, the atomic ratio of tin to zinc is preferably 1 or higher.

In the target used In the fourth aspect, it is more preferable to use an oxide target In which indium oxide and zinc oxide are formed of In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20) and the hexagonal layered compound is localized in the indium oxide crystal.

In the above formula representing the hexagonal layered compound, m is 2 to 20, preferably 2 to 8, more preferably 2 to 6.

The purity of the target used in the fourth aspect is preferably 98% or more.

If the purity is less than 98%, the chemical stability, conductivity or light transmittance of the obtained thin film is deteriorated due to the presence of impurities.

Therefore, the purity is more preferably 99% or more, and most preferably 99.9% or more.

In the case of using a sintered target, the relative density (theoretical density) of the target is preferably 96% or more. If the relative density is less than 96%, a decrease in film formation rate or film quality is liable to be caused.

Therefore, the relative density of the sintered target is more preferably 97% or more, and most preferably 98% or more.

The relative density (theoretical density) of the target is a total value calculated from the densities of the respective raw materials and their respective added total amounts (% by weight).

(2) Crystallization treatment

As for the transparent conductive oxide of the fourth aspect, it is preferable to make the transparent conductive oxide into an amorphous thin film by sputtering using the above-mentioned target and then crystallize the thin film at 230 ℃ or higher.

The reason why the transparent conductive oxide is prepared in this way when a thin film is obtained by sputtering is that the etching performance of the amorphous transparent conductive oxide is better than that of the crystalline transparent conductive oxide even if the composition of the metal oxide constituting the transparent conductive oxide is the same.

Then, the amorphous transparent conductive oxide is crystallized into the transparent conductive oxide. Such transparent conductive oxide has highly improved conductivity. As shown in fig. 7, such a transparent conductive oxide has stability in resistivity at high temperature or high humidity.

The heat treatment temperature at which the amorphous transparent conductive oxide is crystallized is preferably 250 ℃ or more, and most preferably 280 ℃ or more.

As the heat treatment temperature increases, more satisfactory results will be produced due to the faster crystallization rate. However, the heat treatment temperature is preferably set at a temperature that does not cause thermal deformation of the transparent substrate. Therefore, for example, in the case of using a resin as a substrate, the heat treatment temperature is preferably 250 or higher. In the case of using a glass substrate, the temperature is preferably 500 ℃ or less. The crystal type obtained by the heat treatment is preferably a bixbyite type crystal of the monomeric indium oxide depending on the heat treatment temperature. This is because if other hexagonal layered compounds or spinel-structured compounds are obtained, the conductivity may be lowered due to so-called ion impurity diffusion.

The effect of the crystallization temperature will be described in more detail with reference to fig. 10.

The horizontal axis in fig. 10 represents the heat treatment temperature (deg.c) as the crystallization temperature, and the vertical axis therein represents the resistivity (μ Ω · cm).

As can be readily seen from fig. 10, if the heat treatment temperature is lower than 230 ℃, the resistivity becomes very high, i.e., 3,200 μ Ω · cm. In contrast, if the heat treatment temperature exceeds 350 ℃, the resistivity increases, i.e., 1,000 μ Ω · cm.

Conversely, according to fig. 10, in order to effectively lower the value of the resistivity to, for example, 500 μ Ω · cm or less, the heat treatment temperature is preferably 230 to 320 ℃, more preferably 240 to 300 ℃, and most preferably 250 to 290 ℃.

(3) Etching treatment

The transparent conductive oxide of the fourth aspect is preferably etched to have a given shape.

That is, the amorphous transparent conductive oxide made into a thin film by sputtering can be easily etched using, for example, an aqueous solution of oxalic acid at a concentration of 5 wt%.

The etching performance can be improved by increasing the temperature of the etching process. For example, in the case of etching at 40 to 50 ℃, the etching rate may be 0.1 μm/min or more.

Accordingly, the amorphous transparent conductive oxide is characterized by being more easily etched without using a strong acid such as hydrochloric acid or aqua regia as an etching solution or without complicated operations such as attaching a protective film on a wiring electrode as performed in a conventional ITO film.

Particularly preferably, an aqueous solution of oxalic acid having a concentration of 3 to 10% by weight is used as the etching solution. If the concentration of oxalic acid in the aqueous solution is less than 3% by weight, a sufficient etching rate cannot be obtained. On the other hand, if the concentration exceeds 10% by weight, crystals may be generated in the solution.

It is also preferable to set the temperature of the etching solution to 30 to 90 ℃. This is because if the temperature of the etching solution is lower than 30 ℃, the etching rate is significantly reduced, and if the temperature of the etching solution is higher than 90 ℃, it will be difficult to handle the etching solution.

Therefore, the temperature of the etching solution is more preferably 35 to 70 ℃, most preferably 40 to 50 ℃.

(4) Thickness of film

The shape of the transparent conductive oxide is not particularly limited. For example, a film shape is preferable.

In this case, the film thickness may be appropriately selected according to the use of the film, the base material on which the transparent conductive oxide is provided, and the like. The film thickness is preferably 3 to 3,000 nm in the same manner as in the third aspect.

(5) Multilayer composite material

For the transparent conductive oxide, it is preferable to configure a gas barrier layer, a hard coat layer, an antireflection layer, or the like on the surface of the substrate opposite to the surface on which the transparent conductive oxide is provided, thereby constituting a multilayer composite.

As a material forming the gas barrier layer, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyacrylonitrile, polyvinylidene 1, 1-dichloroethylene, polyvinylidene 1, 1-difluoroethylene, or the like can be used.

As the material for forming the hard coat layer, a hard coat agent based on titanium or silica, a polymer material such as polymethyl methacrylate or an inorganic high molecular material such as polyphosphazene may be used, as the material for forming the anti-reflection layer, a low-reflectance polymer, a fluoride such as MgF, may be used₂Or CaF₂Oxides such as SiO₂、ZnO、BiO₂Or Al₂O₃。

In the transparent conductive oxide of the present invention, an organic polymer thin film or an inorganic thin film may be formed on the surface thereof.

(6) Method for preparing a surface

Film forming apparatus

Second, the transparent conductive oxide of the present invention can be prepared by any of various methods such as sputtering, ion plating, vapor deposition, and laser ablation.

Sputtering is more preferably used from the viewpoint of the properties of the transparent conductive oxide, the productivity thereof, and the like.

The sputtering may be ordinary sputtering (referred to as direct sputtering), such as RF magnetron sputtering or DC magnetron sputtering; or reactive sputtering. That is, the composition of the sputtering target used and the sputtering conditions can be appropriately selected according to the composition of the transparent conductive oxide.

② film formation conditions 1

The sputtering conditions when the transparent conductive oxide is provided on the transparent substrate by direct sputtering vary depending on the direct sputtering method, the composition of the sputtering target, the properties of the apparatus used, and the like. It is difficult to specify the sputtering conditions unconditionally. However, in the case of DC magnetron sputtering, the following conditions are preferably set exemplarily.

(degree of vacuum)

Regarding the degree of vacuum achieved in the direct sputtering, it is preferable to reduce the pressure in the vacuum chamber to 1 × 10 in advance before sputtering^-3Pa or less.

The degree of vacuum in sputtering is preferably 1.3X 10^-2Pa to 6.7 Pa.

The reason for this is as follows. If the degree of vacuum in sputtering is higher than 1.3X 10^-2Pa, then the stability is reduced. On the other hand, if the degree of vacuum is less than 6.7Pa, it is difficult to increase the voltage applied to the target.

Therefore, the degree of vacuum in sputtering is more preferably 2.7X 10^-2Pa to 1.3Pa, most preferably 4.0X 10^-2Pa to6.7×10^-1Pa。

(applied Voltage)

The voltage applied to the target in sputtering is preferably 200 to 500 volts.

The reason for this is as follows. If the applied voltage is less than 200V, it becomes difficult to obtain a high-quality thin film or the film forming speed is limited. On the other hand, if the applied voltage is higher than 500 volts, abnormal discharge may be generated.

Therefore, the voltage applied to the target during sputtering is more preferably 230 to 450 volts, and most preferably 250 to 420 volts.

(sputtering gas)

As the sputtering gas (atmosphere gas) in sputtering, an inert gas such as a mixture gas of argon and oxygen is preferable. Therefore, in the case of using argon as the inert gas, the mixing ratio (volume ratio) of argon to oxygen is preferably 0.6: 0.4 to 0.999: 0.001.

That is, the partial pressure of oxygen is preferably 1X 10^-4To 6.7X 10^-1Pa, more preferably 3X 10^-4To 1X 10^-1Pa, most preferably 4X 10^-4To 7X 10^-2Pa。

The transparent conductive oxide obtained outside the range of the mixing ratio and the oxygen partial pressure does not have either low resistance or high light transmittance.

(iii) film Forming Condition 2

In a method of disposing a transparent conductive oxide on a transparent substrate by reactive sputtering, a target made of an alloy of indium, tin, and zinc is used as a sputtering target.

The alloy target may be obtained, for example, by dispersing powders or chips of tin and zinc in molten indium and then cooling the dispersion.

In the same manner as in the target in direct sputtering, the purity of the alloy target is preferably 98% or more, more preferably 99% or more, and most preferably 99.9% or more.

The conditions of reactive sputtering vary depending on the composition of the sputtering target, the properties of the apparatus used, and the like. However, the degree of vacuum at the time of sputtering and the voltage applied to the target are the same as those at the time of DC direct sputtering.

It is preferable to use an inert gas such as a mixed gas of argon and oxygen as the atmosphere gas. The percentage of oxygen is preferably higher than in direct sputtering.

In the case of using argon as the inert gas, the mixing ratio (volume ratio) of argon to oxygen is preferably 0.5: 0.5 to 0.99: 0.01.

(7) Use of

Since the transparent conductive oxide of the fourth aspect has the above-described properties, the transparent conductive oxide is suitable for transparent electrodes of liquid crystal displays, transparent electrodes of electroluminescence displays, transparent electrodes of solar cells, raw materials when these transparent electrodes are produced by etching, antistatic films, and freeze-proof heaters for glazing glass, and the like.

[ fifth aspect ]

The fifth aspect is an embodiment of the fifth invention and is the transparent conductive oxide of the third or fourth aspect, wherein a half-peak width of a binding energy peak of an oxygen 1S orbital determined by X-ray photoelectron spectroscopy (XPS) is set to 3eV or less.

(1) Half-peak width of binding energy peak of oxygen 1S orbital

The transparent conductive oxide of the fifth aspect is obtained by using the targets of the first to second aspects and by film formation by sputtering.

The half-width of the binding energy peak of the oxygen 1S orbital in the surface of the transparent conductive oxide as measured by X-ray photoelectron spectroscopy (XPS) is preferably 3eV or less.

This is because if the half-peak width exceeds 3eV, the initial wire resistivity increases or the wire resistance significantly increases in long-term use.

However, if the half width is 1eV or less, the selection range of usable raw materials is excessively limited or it is difficult to control the half width.

Therefore, the half-width is more preferably 1 to 2.9eV, and most preferably 2.0 to 2.8 eV.

The reason why the half-peak width of the binding energy peak of the oxygen 1S orbital is limited in the above range in this way is based on the following finding.

That is, when the surface condition of the transparent conductive oxide made into a thin film by sputtering is measured by means of X-ray photoelectron spectroscopy (XPS), as shown in fig. 13, two peaks appear, one of which is a peak generated by its metal oxide and the other is a peak generated by a combination of an element other than metal-oxygen-metal, such as hydrogen or carbon. In the case where the transparent conductive oxide in which the peak is generated by the combination of elements other than metal-oxygen-metal (i.e., in which the peak value of the binding energy of the oxygen 1S orbital is relatively large) is connected to an external circuit such as a liquid crystal driving circuit, the wiring resistance thereof increases or the wiring resistance thereof increases upon long-term use.

Therefore, in the fifth aspect, the half-peak width of the binding energy peak of the oxygen 1S orbital in the surface of the transparent conductive oxide measured by X-ray photoelectron spectroscopy (XPS) is set in the above range. Thus, the initial wiring resistance is reduced, and the tendency that the wiring resistance gradually increases in long-term use is further suppressed.

(2) Measuring method

The half-peak width of the binding energy peak of the oxygen 1S orbital in the transparent conductive oxide surface can be calculated from the oxygen 1S orbital peak and its baseline.

That is, as shown in FIG. 12, the peak of the binding energy of the oxygen 1S orbital obtained using X-ray photoelectron spectroscopy (XPS) was taken as the peak of the oxygen 1S orbital.

Then, among the oxygen 1S orbital peaks obtained, the baseline thereof was determined using the Shirley equation. Because the length from the baseline to the peak can be obtained, the midpoint location of the length can be determined.

Then, in the position of the midpoint of the determined length, the binding energy width of the oxygen 1S orbital can be actually measured. The binding energy width is therefore defined as the half-peak width.

(3) Control of half-peak width

(ii) Water content in the vacuum chamber

The half-width of the binding energy peak of the oxygen 1S orbital of the transparent conductive oxide measured by X-ray photoelectron spectroscopy is easily controlled by the water content in the vacuum chamber at the time of sputtering.

That is, in order to obtain a transparent conductive oxide having a half-peak width of 3eV or less, the water content in the vacuum chamber is set to 1X 10 at the time of forming a thin film by sputtering^-5To 1X 10^-10Pa。

More preferably, the water content in the vacuum chamber is maintained at 1X 10^-6To 1X 10^-10Sputtering is performed in the range of Pa.

Applied voltage

When the transparent conductive oxide thin film is produced by sputtering, the half-width of the transparent conductive oxide can be controlled by a voltage applied to the sputtering target.

For example, the voltage applied in the same manner as in the fourth aspect is preferably 200 to 500V.

③ sputtering gas

In order to easily control the half-width of the transparent conductive oxide within the above range, it is preferable to use a mixed gas of an inert gas such as argon and oxygen as the sputtering gas (atmosphere gas).

When argon is used as the inert gas in the mixed gas, the mixing ratio (volume ratio) of argon to oxygen is preferably 0.6: 0.4 to 0.999: 0.001.

When this mixed gas is used, the conductivity of the obtained transparent conductive oxide becomes better. The transparent conductive oxide obtained also has high light transmittance.

(4) Substrate

As the substrate used in preparing the transparent conductive oxide, a glass substrate or a film-like substrate or a sheet-like substrate made of a transparent resin is preferable.

Examples of the glass substrate include glass plates made of soda-lime-silica glass, lead glass, borosilicate glass, high-purity silica glass, alkali-free glass, and the like. Of these glass plates, alkali-free glass is more preferable because alkali metal ions do not diffuse into the transparent conductive oxide.

The light transmittance of the transparent substrate (transparent glass substrate or substrate made of transparent resin) used herein is 70% or more, preferably 80% or more, more preferably 90% or more.

The thickness of the transparent substrate may be appropriately selected depending on the use of the transparent conductive oxide or the material thereof. Typically, the thickness is from 15 microns to 3 mm, more preferably from 50 microns to 1 mm.

(5) Intermediate layer

In the fifth aspect, an intermediate layer having a thickness of 0.5 to 10 μm is preferably provided on the surface of the substrate on the side on which the transparent conductive oxide is provided, in order to improve the adhesion of the substrate to the transparent conductive oxide.

Suitable as the intermediate layer is a layer made of a metal oxide (which may be silicon oxide), a metal nitride (which may be silicon nitride), a metal carbide (which may be silicon carbide), a crosslinked resin, or the like, having a single-layer structure or a multi-layer structure.

Examples of the metal oxide include Al₂O₃SiO (x is more than 0 and less than or equal to 2), ZnO and TiO₂. Metal nitride AlN, Si₃N₄And TiN. Examples of metal carbides include SiC and B₄C. Examples of the crosslinking resin include epoxy resins, phenoxyethyl ether resins, and acrylic resins.

In the case of using a substrate made of a transparent resin as such an intermediate layer, the shape thereof preferably has a two-layer structure in which a crosslinked resin layer and an inorganic material layer are sequentially provided.

In the case of using a transparent glass material as the transparent substrate, the shape thereof preferably has a two-layer structure in which an inorganic material layer and a crosslinked resin layer are sequentially disposed.

In each case, a transparent conductive oxide with better thermal stability can be obtained if the inorganic material is arranged as an intermediate layer in contact with the transparent conductive oxide on one side.

In the case where the crosslinked resin layer is provided on the surface of the substrate made of a transparent resin as an intermediate layer, an adhesive layer or a gas barrier layer may be interposed between the surface of the substrate and the crosslinked resin layer. Examples of the adhesive used for forming the adhesive layer include epoxy resins, acryl urethanes and phenoxyethylether adhesives. In the case where the transparent conductive material is used as a transparent electrode of a liquid crystal display, the gas barrier layer can prevent water vapor, oxygen, or the like from diffusing into the liquid crystal.

(6) Transparent conductive oxide

Etching

The transparent conductive oxide of the fifth aspect is amorphous and has excellent etching properties. Accordingly, the amorphous transparent conductive oxide is more easily etched without using a strong acid such as hydrochloric acid or aqua regia as an etching solution or without complicated operations such as attaching a protective film on a wiring electrode as performed in a conventional ITO film.

It is preferable to use an aqueous solution of oxalic acid having a concentration of 3 to 10% by weight as an etching solution of the amorphous transparent conductive oxide, which does not cause corrosion of a wiring electrode in a display device.

The reason for this is as follows. If the concentration of oxalic acid in the aqueous solution is less than 3% by weight, a sufficient etching rate cannot be obtained. On the other hand, if the concentration of oxalic acid in the aqueous solution exceeds 10% by weight, crystals are liable to be generated in the solution.

② Heat treatment

The amorphous transparent conductive oxide is preferably patterned by etching and then crystallized by heat treatment, thereby improving conductivity and further stabilizing resistance at high temperature or high humidity.

In this case, the heat treatment temperature for crystallization is preferably 230 ℃ or higher, more preferably 250 ℃ or higher, and most preferably 280 ℃ or higher.

As the heat treatment temperature increases, more satisfactory results will be produced due to the faster crystallization rate. However, it is preferable to set the heat treatment temperature at a temperature that does not cause thermal deformation of the transparent substrate or lower. For example, in the case of using a resin as a substrate, the heat treatment temperature is preferably 250 ℃ or less. In the case of using a glass substrate, the heat treatment temperature is preferably 500 ℃ or less.

Thickness of film

The film thickness may be appropriately selected depending on the use of the film, the base material on which the transparent conductive oxide is provided, and the like. The film thickness is preferably 3 to 3,000 nm in the same manner as in the third aspect or the fourth aspect.

Application

The transparent conductive oxide is suitable for use as a transparent electrode of a liquid crystal display, a transparent electrode of an electroluminescent display, a transparent electrode of a solar cell, etc. to fully utilize its excellent transparency, conductivity and etching property.

[ sixth aspect ]

The sixth aspect is an embodiment relating to the sixth aspect, wherein a transparent conductive oxide is formed on a colored layer provided on a substrate. This first embodiment is described below by way of an example of a color filter layer.

(1) Structure of the product

As shown in fig. 11(d), the color filter layer of the sixth aspect is a color filter layer made by sequentially disposing an organic coloring layer 12 and a transparent conductive film (electrode) 24 on a substrate 10. The organic coloring layer 12 is composed of RGB pixels (red pixel, green pixel, and blue pixel) 14, 16, and 18 and a black matrix (light shielding layer) 20 disposed therein.

The color filter layer is a color filter layer comprising 67 to 93%, preferably 74 to 93%, by weight of indium oxide, 5 to 25%, preferably 5 to 20%, by weight of tin oxide and 2 to 8%, preferably 2 to 6%, by weight of zinc oxide; a composition having a composition in which the atomic ratio of tin to all metal atoms is not less than the atomic ratio of zinc to all atoms; and has a transparent conductive film 24 as an electrode by crystallizing it by heat-treating the transparent conductive film 22 (which is amorphous when set) at 200 ℃ or higher, preferably at 230 to 300 ℃.

(2) Transparent conductive film

The reason why the composition of the transparent conductive oxide constituting the transparent conductive thin film is set in the above range is that the sintered body target composed of the transparent conductive oxide having the composition can make sputtering at low temperature possible.

That is, when a transparent conductive film is made of the sintered body by using sputtering, an amorphous transparent conductive film having excellent etching properties can be formed on an organic colored layer even at a substrate temperature of 200 ℃ or less.

Therefore, the fear that the organic coloring layer as the undercoat layer is damaged at the time of sputtering can be eliminated.

The thickness of the transparent conductive film is preferably 3 to 3,000 nm as described in the first aspect.

(3) Substrate

Examples of the substrate used in the color filter layer include a film or sheet made of glass or a synthetic resin excellent in transparency, such as polycarbonate, polyethylene terephthalate (PET), polyacrylate, and polyether sulfone.

(4) Coloured layer

The organic colored layer disposed on the substrate may be formed directly on the substrate, or the pixels of the organic colored layer may be independent of each other in plan view with a further light-shielding layer interposed therebetween (black matrix).

Next, in the organic colored layer disposed on the base or adjacent to the light-shielding layer, a composition composed of a colorant and a binder resin is used.

Examples of the colorant that can be used include a perylene pigment, a lake pigment, an azo pigment, an quinacridone pigment, an anthraquinone pigment, an anthracene pigment, an isoindoline pigment, a phthalocyanine pigment, a trityl dye, an indanthrone pigment, an indophenol pigment, a cyanine pigment, and a dioxadine (dioxadine) pigment.

The binder resin is preferably a heat-resistant resin. Suitable for use are, for example, epoxy resins, urethane resins, urea resins, acrylic resins, polyvinyl alcohol resins, polyimide resins or mixtures thereof. Among these resins, polyimide is particularly preferable because of its high heat resistance.

Further, the kind of the light-shielding layer is not particularly limited as long as it can prevent interaction between each organic colored layer. For example, a layered product composed of a chromium film, a partially oxidized chromium film, a black-dyed organic colored layer, or the like is suitably used.

(5) Preparation method

Formation of colored layer

As shown in fig. 11(b), in order to form the organic coloring layer 12, it is preferable that pigments in red, blue and green colors selected from the above-mentioned coloring agents and a binder resin are mixed and dispersed in a solvent for them, respectively, to obtain a paste, followed by making RGB pixels by a photolithography method.

For example, it is desirable to coat the paste on a substrate processed into a stripe shape or a photoblack compensation layer, semi-cure the paste, form a stripe-shaped green organic coloring layer (G pixels) corresponding to the pixels by a photolithography method, and then cure it.

Red and blue organic coloring layers (R pixels and pixels) can also be made in the same manner.

If necessary, a protective film made of a polyimide resin is formed on the organic coloring layer.

Formation of amorphous transparent conductive film

Then, as shown in fig. 11(c), an amorphous transparent conductive film is formed on the organic colored layer or the protective film provided on the organic colored layer.

Preferably, the amorphous transparent conductive film is produced by using a target composition comprising 67 to 93%, preferably 74 to 93% by weight of indium oxide, 5 to 25%, preferably 5 to 20% by weight of tin oxide and 2 to 8%, preferably 2 to 6% by weight of zinc oxide, wherein the atomic ratio of tin to all metal atoms is not less than the atomic ratio of zinc to all atoms, and further comprising a hexagonal layered compound having a crystal grain diameter of 5 μm or less.

When the transparent conductive film is formed on an organic colored layer or a protective layer, a magnetron sputtering apparatus is suitable.

Therefore, the conditions when the amorphous transparent conductive film is produced are somewhat varied depending on the area and thickness of the target. Usually by setting the plasma output to 0.3 to 4W/cm²The target area and the forming time are 5 to 120 minutesAn amorphous transparent conductive film having a desired thickness.

The thickness of the amorphous transparent conductive film, which varies depending on the kind of display device to which the film is applied, is generally 3 to 3,000 nm, preferably 20 to 600 nm, and more preferably 30 to 200 nm.

Etching of amorphous transparent conductive film

The obtained amorphous transparent conductive film is far superior to any crystalline transparent conductive film in etching performance. Therefore, in the etching treatment to form a certain pattern, a weak acid aqueous solution which does not cause corrosion of the wiring material, for example, an aqueous solution in which the oxalic acid concentration is 3 to 10% by weight may be used.

For example, under the condition of using a solution having an oxalic acid concentration of 5 wt% as an etching solution at 40 to 50 ℃, the amorphous transparent conductive oxide has excellent etching properties such that an etching rate can reach 0.1 μm/min or more.

Crystallization of transparent conductive film

Then, as shown in fig. 11(d), after the amorphous transparent conductive film formed is patterned by etching, the film is preferably subjected to a heat treatment to crystallize it. Thus, a crystalline transparent conductive film having excellent heat resistance and moisture resistance is obtained.

Preferably, the heat treatment conditions in this case are 200 ℃ or more, preferably 230 ℃ or more, more preferably 250 ℃ or more, and the treatment time is 0.5 to 3 hours.

[ seventh aspect ]

The seventh aspect relates to the method for producing the sputtering target of the first and second inventions, which is the first production method for a sputtering target, wherein said sputtering target comprises In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20) of a hexagonal layered compound having a crystal grain diameter set to 5 μm or less, the method comprising steps (1) to (3):

(4) the shaped body is sintered at a temperature of 1400 ℃ or higher.

(1) Mixing step

Mixing flour mill

The respective metal oxides used as the components for preparing the target are uniformly mixed and ground using a conventional mixing pulverizer such as a wet ball mill, bead mill (bead mill) or ultrasonic device.

② average particle size of powdery component

In mixing and pulverizing the powdery ingredients, it is preferable to pulverize the powder into finer particles because it is easy to control the grain size (5 μm or less) of the hexagonal layered compound in the target. In particular, indium oxide powder, zinc oxide powder, and the like are preferably mixed-milled so that the average particle size thereof is 2 micrometers or less, more preferably 0.1 to 1.8 micrometers, still more preferably 0.3 to 1.5 micrometers, and most preferably 0.5 to 1.2 micrometers.

Meanwhile, in the case of mixing tin oxide powder to produce a spinel-structured compound, the average particle size of the tin oxide powder is preferably 0.01 to 1 micron, more preferably 0.1 to 0.7 micron, most preferably 0.3 to 0.5 micron.

This is because it is easy to control the grain diameter (5 μm or less) of the hexagonal layered compound and the spinel-structured compound in the target by limiting the average particle size of the tin oxide powder to such a range.

③ kinds of powdery components

The indium compound and the zinc compound used as the components are preferably oxides or compounds to be oxidized after sintering, that is, indium oxide precursors or zinc oxide precursors.

Examples of the indium oxide precursor and the zinc oxide precursor include sulfides, sulfates, nitrates, halides (chlorides, bromides, etc.), carbonates, organic acid salts (acetates, oxalates, propionates, naphthoates, etc.), alkoxides (methoxides, ethoxides, etc.), and organic metal complexes (acetylacetonates, etc.) of indium and zinc.

Among them, nitrates, organic acid salts, alkoxides and organometallic complexes are preferable because they are completely thermally decomposed even at low temperatures and thus leave no impurities.

(2) Step of presintering

Then, after obtaining a mixture of the indium compound, the zinc compound and the tin compound, the mixture is preferably presintered, which is an optional step.

In the pre-sintering step, the heat treatment is preferably performed at 500 to 1,200 ℃ for 1 to 100 hours.

This is because thermal decomposition of the indium compound, the zinc compound and the tin compound may be insufficient under the heat treatment condition of less than 500 ℃ or less than 1 hour. On the other hand, if the heat treatment conditions exceed 1,200 ℃ or exceed 100 hours, the particles may become coarse and increase in size.

Therefore, it is particularly preferable to perform the heat treatment (pre-sintering) at a temperature of 800 to 1,200 ℃ for 2 to 50 hours.

The pre-sintered body obtained here is preferably ground prior to forming and sintering. The milling of the pre-sintered body is preferably performed using a ball mill, a roll mill, a bead mill (pearl mill), a jet mill, or the like so that the particle size thereof is 0.01 to 1.0 μm.

(3) Shaping step

Next, the obtained pre-sintered body is formed into a shape suitable for the target in this forming step.

Such molding may be performed by molding, casting, injection molding, or the like. In order to obtain a sintered body having a high sintered density, it is preferable to shape the pre-sintered body by CIP (cold isostatic pressing) or the like, and then subject the obtained shaped body to a sintering treatment which will be described below.

In the forming process, a forming aid such as polyvinyl alcohol, methyl cellulose, wax (polywax) or oleic acid may be used.

(4) Sintering step

Next, the obtained fine powder is granulated, then formed into a desired shape by extrusion molding, and the compact is sintered and subjected to HIP (hot isostatic pressing) sintering or the like.

As for the sintering conditions in this case, the sintering is generally carried out at 1,400 to 1,600 ℃, preferably 1,430 to 1,550 ℃, more preferably 1,500 to 1,540 ℃ under an oxygen or compressed oxygen atmosphere for 30 minutes to 72 hours, preferably 10 hours to 48 hours.

During this time, if a mixture of indium oxide powder and zinc oxide powder is sintered in an atmosphere containing no oxygen or at a temperature lower than 1,400 ℃, the reactivity of zinc oxide with indium oxide decreases so that hexagonal layered compound crystals cannot be completely formed. As a result, the density of the obtained target cannot be sufficiently improved, and therefore, the generation of spherical objects at the time of sputtering cannot be completely suppressed.

The rate of temperature rise in this case is preferably 10 to 50 ℃/min.

If a mixture of indium oxide powder and zinc oxide powder having the above-mentioned ratio is sintered at a temperature of 1,400 deg.c or more in an oxygen atmosphere or a compressed oxygen atmosphere in this manner, hexagonal layered compound crystals composed of indium oxide and zinc oxide are produced, which are unevenly distributed in the gaps between the indium oxide crystal grains. This suppresses the growth of indium oxide crystals, thereby forming a sintered body having a fine crystal structure.

In the above mixing step, at least zinc oxide having an average particle size of 2 μm or less is used; therefore, the grain size of the obtained sintered body is 5 μm or less.

(5) Reduction step

In order to make the volume resistance of the obtained sintered body more uniform as a whole, it is preferable to perform a reduction treatment in the reduction step, which is an optional step.

Such reduction methods are methods based on reducing gases or on vacuum sintering or reduction with inert gases.

In the case of a reducing gas, hydrogen, methane, carbon monoxide, a mixed gas of these gases and oxygen, or the like may be used.

The reduction temperature is from 100 to 800 ℃ and preferably from 200 to 800 ℃. The reduction time is 0.01 to 10 hours, preferably 0.05 to 5 hours.

(6) Processing step

Preferably, the sintered body obtained by such sintering is cut into a shape suitable for fitting to a sputtering apparatus at this processing step, and a fitting is fixed to the cut body to make a sputtering target.

In the sputtering target obtained in the last step, the composition of each metal oxide constituting the composition of the sputtering target is adjusted to the above range, and these oxide particles having a size of 2 μm or less are used for sintering at a temperature of 1,400 ℃ or more in an atmosphere of oxygen or compressed oxygen, so that indium oxide and zinc oxide exist as hexagonal layered compound crystals. Therefore, the volume resistance of the target is reduced, and the target has a fine crystal structure in which the grain size is 5 μm or less.

Accordingly, when a thin film is formed by sputtering using this target, generation of spherical objects is suppressed. Since the dispersion of the spherical objects due to the plasma is significantly reduced, the sputtering is more stabilized, thereby obtaining a high-quality transparent conductive oxide having no foreign matter attached thereto.

[ eighth aspect ]

The eighth aspect relates to the other production method of the first and second inventions, which is the second production method of a sputtering target, wherein said sputtering target comprises In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20) and a crystal grain diameter of 5 μm or less. The method is a method for producing a sputtering target, characterized by comprising steps (1) to (5):

(5) the shaped body is sintered at a temperature of 1400 ℃ or higher.

If a sputtering target is prepared in this manner, the average particle size of the hexagonal layered compound and the like in the target must be strictly adjusted. Therefore, the formation of the spherical object can be effectively prevented when sputtering is performed using the target.

(1) Step of preparing hexagonal layered Compound

Preparation of In₂O₃(ZnO)_m(wherein m is a positive integer of 2 to 20), indium oxide (In) as a component is preferably uniformly mixed using a wet ball mill, a bead ball mill or an ultrasonic device In the same manner as In the seventh aspect₂O₃) And zinc oxide (ZnO).

Next, in order to obtain a hexagonal layered compound, the mixture is preferably subjected to a heat treatment at a temperature of 1200 to 1300 ℃ for 30 minutes to 3 hours.

Since the average particle size of the hexagonal layered compound is controlled in the particle size adjusting step to be described later, it is not necessary to make the average particle sizes of indium oxide and zinc oxide 2 μm or less in the preparation step of the hexagonal layered compound.

(2) Step of adjusting particle size of hexagonal layered compound

This is a step of making the average particle size of the hexagonal layered compound to be prepared 5 μm or less. By adjusting the particle size of the hexagonal layered compound in this way, the formation of a sphere can be effectively prevented when the obtained target is used.

However, if the average particle size of the hexagonal layered compound is too small, the control thereof becomes more difficult or the yield is lowered, resulting in economic disadvantages. Therefore, the average particle size of the hexagonal layered compound is more preferably 0.1 to 4 μm, most preferably 0.5 to 3 μm.

There is no particular limitation on the method for adjusting the particle size of the hexagonal layered compound. However, the conditioning may be accomplished by, for example, uniformly milling the compound in a wet ball mill, bead mill or ultrasonic apparatus, and then sieving the obtained particles.

(3) Step of mixing indium oxide powder

This is a step of mixing the hexagonal layered compound whose particle size has been adjusted with the indium oxide powder.

That is, the indium oxide powder is preferably mixed so that the atomic ratio of In/(In + Zn) In the compact is 0.75 to 0.97.

It is also preferable to add the spinel structure compound together with the indium oxide powder. Namely, tin oxide (SnO)₂) And zinc oxide (ZnO) is heat-treated at a temperature of 800 to 1200 c for 30 minutes to 3 hours. The particle size was then adjusted to 5 microns or less and the addition was carried out at this stage.

(4) Step of preparing molded article

The conditions in this step are preferably the same as in the seventh aspect. That is, in order to obtain a dense target, it is preferable to prepare a compact in advance by CIP (cold isostatic pressing) or the like.

(5) Sintering step

The conditions in this step are preferably the same as in the seventh aspect. That is, the molded body obtained in (4) is preferably sintered at 1,400 to 1,600 ℃ for 30 minutes or 72 hours in an atmosphere of oxygen or compressed oxygen.

Examples

The invention will now be described in more detail with the aid of examples and comparative examples.

[ example 1]

(1)

Preparation of the target

Indium oxide having an average particle size of 1 μm and zinc oxide having an average particle size of 1 μm were used as raw materials, mixed with each other In such a manner that the atomic ratio of In/(In + Zn) was 0.83, and charged into a wet ball mill, and mixed and ground for 72 hours to obtain a fine powdery raw material.

The fine powdery raw material was granulated, and the obtained granules were then compacted to a size of 10 cm in diameter and 5 mm in thickness. This was put into a sintering furnace and sintered at 1,450 ℃ for 36 hours in a compressed oxygen gas to obtain a sintered body (target) made of a transparent conductive oxide.

Evaluation of targets

The density, volume resistance, X-ray diffraction analysis, crystal grain size and various physical properties of the obtained target were measured.

The density of the sintered body was 6.8g/cm³The volume resistance measured by the 4-probe method was 0.91X 10^-3Ω.cm。

A sample was obtained from the sintered body, and the condition of crystals in the transparent conductive material was observed by X-ray diffraction analysis. The results demonstrate the presence of In the obtained target₂O₃(ZnO)₃A hexagonal layered compound represented by and made of indium oxide and zinc oxide.

The obtained sintered body was covered with a resin, and the surface thereof was polished with alumina particles having a particle size of 0.05 μm. Thereafter, the maximum grain size of the hexagonal layered compound in a 30-square micrometer frame of the sintered body surface magnified 5,000 times was measured using JXA-8621MX (manufactured by JEOL ltd.) as EPMA. The maximum particle size in the box was measured at 3 points in the same manner. Their average value is calculated. This proves that the grain size in the sintered body is 3.0 μm.

The sintered body obtained in (r) was cut to prepare a sputtering target having a diameter of 10 cm and a thickness of about 5 mm [ A1 ]. Then, the physical properties thereof were measured.

(2) Making transparent conductive oxide into film

The sputtering target [ A1] obtained in the above (1) was fixed on a DC magnetron sputtering apparatus, and a thin film of a transparent conductive oxide was formed on a glass substrate at room temperature.

Sputtering conditions were that argon gas mixed with an appropriate amount of oxygen was used and the sputtering pressure was 3X 10^-1Pa, the final pressure reached is 5X 10^-4Pa, the substrate temperature was 25 ℃, the applied electric power was 100W, and the film formation time was 20 minutes.

As a result, a transparent conductive glass was obtained in which a transparent conductive oxide was formed on a glass substrate to a film thickness of about 120 nm.

(3) Number of balls produced

Sputtering was continuously performed under the same conditions as in (2) above for 8 hours, except that the sputtering target [ A1] obtained in (1) was fixed on a DC magnetron sputtering apparatus and a mixed gas of 3% hydrogen gas added to argon gas was used.

Next, the target surface after sputtering was enlarged by 30 times and observed with the aid of a stereomicroscope. In 3 positions of the target, 900mm was measured²The number of spheres having a size of 20 μm or more generated in the visual field was then averaged.

As a result, as shown in FIG. 1 (photograph), no spherical particles were found on the surface of the sputtering target [ A1] obtained in the above (1).

(4) Evaluation of physical Properties of transparent conductive oxide

The conductivity of the transparent conductive oxide on the transparent conductive glass obtained in the above (2) was measured for its resistivity by a four-probe method. As a result, the resistivity thereof was 2.5X 10^-4Omega cm. The transparent conductive oxide is amorphous as also confirmed by X-ray diffraction analysis. The smoothness of the film surface was also proved to be good because the P-V value (according to JISB0601) was 5 nm.

Further, regarding the transparency of the transparent conductive oxide, the transmittance of light having a wavelength of 500 nm was 82% as confirmed by an optical rotation spectrometer. Therefore, the transparency is also excellent.

[ examples 2 to 3]

(1) Preparation of sputtering targets

Targets [ B1] and [ C1] were obtained In the same manner as In example 1, but In examples 2 and 3, a mixture In which the same indium oxide and zinc oxide as In example 1 were mixed In such a manner that the atomic ratio of In/(In + Zn) was 0.93 and a mixture In which the same indium oxide and zinc oxide as In example 1 were mixed In such a manner that the atomic ratio of In/(In + Zn) was 0.95 were used as raw materials, respectively.

The results of measuring the compositions and physical properties of the targets [ B1] and [ C1] are shown in Table 1.

(2) Evaluation of target and transparent conductive oxide

In the same manner as in example 1, transparent conductive oxides were prepared from [ B1] and [ C1], respectively. The target and transparent conductive oxide were evaluated. The results obtained are shown in table 2.

[ comparative examples 1 to 2]

(1) Preparation of sputtering targets

The effect of the atomic ratio represented by In/(In + Zn) In the target was investigated.

That is, targets [ D1] and [ E1] were obtained In the same manner as In example 1, but In comparative examples 1 and 2, a mixture In which the same indium oxide and zinc oxide as In example 1 were mixed In such a manner that the atomic ratio of In/(In + Zn) was 0.98 and a mixture In which the same indium oxide and zinc oxide as In example 1 were mixed In such a manner that the atomic ratio of In/(In + Zn) was 0.6 were used as raw materials, respectively.

The results of measuring the compositions and physical properties of the targets [ D1] and [ E1] are shown in Table 1.

(2) Evaluation of target and transparent conductive oxide

In the same manner as in example 1, transparent conductive oxide films were prepared from [ D1] and [ E1], respectively. The target and transparent conductive oxide were evaluated. The results obtained are shown in table 2.

[ comparative example 3]

(1) Preparation of sputtering targets

The effect of the atomic ratio represented by In/(In + Zn) and the sintering temperature In the target was investigated.

That is, the target [ F1] was obtained In the same manner as In example 1, but the raw material used herein was a mixture of indium oxide and tin oxide In which they were mixed In such a manner that the atomic ratio of indium [ In/(In + Sn) ] was 0.90, and the sintering temperature of the formed body obtained from the raw material was 1,400 ℃.

The results of measuring the composition and physical properties of the target [ F1] are shown in Table 1.

(2) Evaluation of target and transparent conductive oxide

In the same manner as in example 1, a transparent conductive oxide film was prepared from [ F1 ]. The target and transparent conductive oxide were evaluated. The results obtained are shown in table 2.

TABLE 1

	Examples			Comparative examples
	Examples			Comparative examples			1	2	3	1	2	3
	In/(In+Zn)	0.83	0.93	0.95	0.98	0.60	1	2	3	1	2	3	-
In/(In+Sn)	In/(In+Zn)	0.83	0.93	0.95	0.98	0.60	-	-	-	-	-	0.90	-
In/(In+Sn)	Density (g/cm) of sintered body³)	6.8	6.8	6.9	6.9	6.3	-	-	-	-	-	0.90	6.9
Volume resistance (m omega cm)	Density (g/cm) of sintered body³)	6.8	6.8	6.9	6.9	6.3	0.91	0.94	0.97	2.1	5.4	0.62	6.9
Volume resistance (m omega cm)	Grain size (μm)	3.0	3.8	4.6	7.8	9.8	0.91	0.94	0.97	2.1	5.4	0.62	18.0
Target code	Grain size (μm)	3.0	3.8	4.6	7.8	9.8	A1	B1	C1	D1	E1	F1	18.0

TABLE 2

		Target code	Number of balls (8 hours/900 mm)²)	Transparent conductive oxide film
				Transparent conductive oxide film		Specific resistance (mu omega cm)	Crystallinity of the compound
				Examples	1	Specific resistance (mu omega cm)	Crystallinity of the compound	A1	0	250	Amorphous form
2	B1	0	230		1	Amorphous form		A1	0	250	Amorphous form
2	B1	0	230		3	Amorphous form	C1	0	180	Amorphous form
Comparative examples	1	D1	18		3	320	C1	0	180	Amorphous form	Microcrystals
	1	D1	18	2	E1	320	8	680	Amorphous form		Microcrystals
	3	F1	32	2	E1	420	8	680	Amorphous form	Crystallization of

[ example 4]

(1) Preparation of sputtering targets

Indium oxide having an average particle size of 1 μm, zinc oxide having an average particle size of 1 μm and tin oxide having an average particle size of 0.5 μm were mixed with each other in such a manner that the percentages of indium oxide, zinc oxide and tin oxide were 75 wt%, 5.5 wt% and 19.5 wt%, respectively, and charged into a wet ball mill. Then the raw materials are mixed and ground to obtain fine powdery raw materials.

The fine powdery raw material obtained here was granulated, and the obtained granules were then compacted to a size of 10 cm in diameter and 5 mm in thickness. This was put into a sintering furnace and sintered at 1,450 ℃ for 36 hours in a compressed oxygen gas to obtain a sintered body made of a transparent conductive oxide.

As a result, the density was 6.8g/cm³The volume resistance measured by the 4-probe method was 0.84X 10^-3Ω.cm。

A sample was obtained from the sintered body, and the condition of crystals in the transparent conductive material was observed by X-ray diffraction analysis. The results are shown in FIG. 6, which demonstrates that tin oxide and zinc oxide are formed from Zn₂SnO₄The spinel structure compound is shown in the form of.

Then, the obtained sintered body was covered with a resin, and the surface thereof was polished with alumina particles having a particle size of 0.5 μm. Thereafter, the maximum size of the maximum crystal of the hexagonal layered compound and the spinel-structured compound at the surface of the sintered body (within a frame of 30 μm square) magnified 5,000 times was measured using EPMA.

The maximum grain size of the largest crystal grain in the box was measured at 3 points in the same manner. Their average value is calculated. The structure proves that the grain size of the hexagonal layered compound and the spinel-structured compound is 4.1 μm.

Then, the obtained sintered body was cut to prepare a sputtering target [ A2] having a diameter of about 10 cm and a thickness of about 5 mm.

The measurement results of the composition and physical properties of the target [ A2] obtained here are shown in Table 3.

(2) Making transparent conductive oxide into film

The sputtering target [ A2] obtained in the above (1) was fixed on a DC magnetron sputtering apparatus, and a transparent conductive oxide thin film was formed on a glass substrate at room temperature.

(3) Number of balls produced

Next, sputtering was continuously performed under the same conditions as in (2) above for 8 hours, except that the sputtering target [ a2] obtained in (1) was fixed on a DC magnetron sputtering apparatus and a mixed gas of 3% hydrogen gas added to argon gas was used.

Then, the target surface after sputtering was enlarged by 30 times and observed with the aid of a stereomicroscope. In 3 positions of the target, 900mm was measured²The number of spheres having a size of 20 μm or more generated in the visual field was then averaged.

As a result, no spherical object was found on the surface of the sputtering target [ A2] obtained in the above (1). The number of spheres produced is shown in table 4.

(4) Evaluation of transparent conductive oxide film

The conductivity (resistivity) of the transparent conductive oxide thin film obtained in the above (2) was measured by a four-probe method. As a result, the resistivity thereof was 2.8X 10^-4Ω.cm。

The transparent conductive oxide thin film is amorphous as also confirmed by X-ray diffraction analysis. Meanwhile, the P-V value of the film is 5 nm as measured by a surface roughness meter, and the smoothness of the surface of the film is good.

Further, regarding the transparency of the transparent conductive oxide film, the light transmittance (wavelength of 500 nm) was measured by an optical rotation spectrometer. As a result, the light transmittance was 82%. Thus, the obtained transparent conductive oxide film was confirmed to have excellent transparency.

(5) Heat treatment of transparent conductive oxide thin films

Heat-treating the transparent conductive glass obtained in the above (2). The heat treatment conditions were as follows. The glass was heated to 215 ℃ under an argon atmosphere at a ramp rate of 20 ℃/min and held at that temperature for 1 hour.

As a result, the obtained transparent conductive oxide thin film was amorphous, but the resistivity thereof was 2.1X 10^-4Ω.cm。

Thus, it was confirmed that the heat treatment can reduce the resistivity of the transparent conductive oxide thin film by about 25%. The change in resistivity of the transparent conductive oxide thin film by the heat treatment is shown in table 4.

(6) Etching processability of transparent conductive oxide film

Next, the etching processability of the obtained transparent conductive oxide thin film was evaluated.

That is, a part of the transparent conductive oxide film on the transparent conductive glass was etched using an oxalic acid aqueous solution (concentration: 50 wt%) at 40 ℃ to form a line having a width of 10 to 100 μm. The cross-sectional shape of the boundary portion between the etched portion and the unetched portion was observed using an electron microscope.

As a result, it was found that no transparent conductive oxide film remained at the etched portion, and the edge portion of the transparent conductive oxide film remained at the unetched portion had a sectional shape smoothly inclined toward the etched portion. Thus, it was confirmed that the obtained transparent conductive oxide thin film had excellent etching processability.

The etching processability of the transparent conductive oxide thin film was evaluated according to the following criteria.

Very good: the film can be etched to have lines with a width of 10 microns and no residue found.

O: the film can be etched to have lines with a width of 50 microns and no residue found.

And (delta): the film may be etched to have lines with a width of 100 microns and found to be partially residual.

X: it is difficult to etch the film to have lines with a width of 100 microns and a large amount of residue is found.

[ examples 5 to 8]

(1) Preparation of sputtering targets

The effect of the raw material mixing ratio was studied.

That is, in example 5, the mixing proportions of indium oxide, tin oxide and zinc oxide were 73 wt%, 20 wt% and 7 wt%, respectively. In example 6, the mixing ratios of indium oxide, tin oxide and zinc oxide were 87 wt%, 10 wt% and 3 wt%, respectively. In example 7, the mixing ratios of indium oxide, tin oxide and zinc oxide were 88 wt%, 10 wt% and 2 wt%, respectively. In example 7, the mixing proportions of indium oxide, tin oxide and zinc oxide were 91 wt%, 7 wt% and 2 wt%, respectively. With the exception of the above ratio, targets [ B2], [ C2], [ D2] and [ E2] were prepared in the same manner as in example 4.

The results of measuring the composition and physical properties of the obtained targets [ B2], [ C2], [ D2] and [ E2] are shown in Table 3.

(2) Evaluation of target and transparent conductive oxide film

From each of the obtained targets [ B2], [ C2], [ D2] and [ E2], a transparent conductive oxide thin film was prepared in the same manner as in example 4. The target and transparent conductive oxide were evaluated. The results obtained are shown in table 4.

[ comparative example 4]

(1) Preparation of sputtering targets

A sputtering target [ F2] was obtained in the same manner as in example 4, except that zinc oxide powder having an average particle size of 3 μm was used as a raw material, and the mixing ratios of the raw materials indium oxide and zinc oxide were 90 wt% and 10 wt%, respectively. The results of measuring the composition and physical properties of the target [ F2] obtained herein are shown in Table 3.

(2) Evaluation of target and transparent conductive oxide film

A transparent conductive oxide thin film was prepared from the obtained target [ F2] in the same manner as in example 4, and the target and the transparent conductive oxide were evaluated. The results obtained are shown in table 4.

[ comparative examples 5 to 7]

(1) Preparation of sputtering targets

The effect of the raw material mixing ratio was studied.

That is, in comparative example 5, the mixing ratio of indium oxide and tin oxide was 90 wt% and 10 wt%, respectively. In comparative example 6, the mixing ratio examples of indium oxide, tin oxide and zinc oxide were 87 wt%, 10 wt% and 3 wt%, respectively. In comparative example 7, the mixing ratio of indium oxide, tin oxide and zinc oxide was 90 wt%, 5 wt% and 5 wt%, respectively.

Next, targets [ G2] and [ I2] were obtained in comparative examples 5 and 7, respectively, in the same manner as in example 4.

In comparative example 6, a target [ H2] was obtained in the manner of example 4, but wherein the sintering temperature of the formed body was 1,100 ℃.

The measurement results of the composition and physical properties of the obtained targets [ G2], [ I2] and [ H2] are shown in Table 3.

(2) Evaluation of target and transparent conductive oxide film

From each of the obtained targets [ G2], [ I2] and [ H2], a transparent conductive oxide thin film was prepared in the same manner as in example 4. The target and transparent conductive oxide were evaluated. The results obtained are shown in table 4.

Target for comparative example 6 [ H2]The crystallinity was observed by X-ray diffraction analysis. As a result, it was found that In is not caused by₂O₃(ZnO)_m(m is a positive integer of 2 to 20).

TABLE 3

	Examples					Comparative examples
	Examples					Comparative examples				4	5	6	7	8	4	5	6	7
	In₂O₃(% by weight)	75	73	87	88	91	90	90	87	4	5	6	7	8	4	5	6	7	90
SnO₂(% by weight)	In₂O₃(% by weight)	75	73	87	88	91	90	90	87	19.5	20	10	10	7	0	10	10	5	90
SnO₂(% by weight)	ZnO (% by weight)	5.5	7	3	2	2	10	0	3	19.5	20	10	10	7	0	10	10	5	5
Density (g/cm) of sintered body³)	ZnO (% by weight)	5.5	7	3	2	2	10	0	3	6.8	6.8	6.9	6.9	7.0	6.9	7.0	6.3	6.4	5
Density (g/cm) of sintered body³)	Volume resistance (m omega cm)	.84	.94	.87	.83	.87	2.1	.87	4.3	6.8	6.8	6.9	6.9	7.0	6.9	7.0	6.3	6.4	1.5
Grain size (μm)	Volume resistance (m omega cm)	.84	.94	.87	.83	.87	2.1	.87	4.3	4.1	3.4	3.8	4.5	4.8	4.2	18	7.4	4.8	1.5
Grain size (μm)	Target code	A2	B2	C2	D2	E2	F2	G2	H2	4.1	3.4	3.8	4.5	4.8	4.2	18	7.4	4.8	I2

TABLE 4

		Target code	Number of balls	Transparent conductive oxide film
				Transparent conductive oxide film					Immediately after the film formation			After heat treatment
				Specific resistance (mu omega cm)	Crystallinity of the compound	Etching performance	Specific resistance (mu omega cm)	Crystallinity of the compound	Immediately after the film formation			After heat treatment
				Specific resistance (mu omega cm)	Crystallinity of the compound	Etching performance	Specific resistance (mu omega cm)	Crystallinity of the compound	Examples	4	A2	0	280	Amorphous form	◎	210	Amorphous form
5	B2	0	290	Amorphous form	◎	230	Amorphous form			4	A2	0	280	Amorphous form	◎	210	Amorphous form
5	B2	0	290	Amorphous form	◎	230	Amorphous form	6		C2	0	270	Amorphous form	○	180	Microcrystals
7	D2	0	260	Amorphous form	○	170	Microcrystals	6		C2	0	270	Amorphous form	○	180	Microcrystals
7	D2	0	260	Amorphous form	○	170	Microcrystals	8		E2	0	240	Amorphous form	△	170	Microcrystals
Comparative examples	4	F2	0	380	Amorphous form	◎	380	8		E2	0	240	Amorphous form	△	170	Microcrystals	Amorphous form
	4	F2	0	380	Amorphous form	◎	380	5	G2	32	260	Crystallization of	×	190	Crystallization of		Amorphous form
	6	H2	18	320	Amorphous form	△	250	5	G2	32	260	Crystallization of	×	190	Crystallization of	Crystallization of
	6	H2	18	320	Amorphous form	△	250	7	I2	21	260	Amorphous form	△	880	Crystallization of	Crystallization of

[ example 9]

(1) Preparation of transparent conductive film

Use of a biaxially stretched polyester film [ polyethylene terephthalate ] having a thickness of 100. mu.m]As a substrate composed of a transparent resin. In is a hexagonal layered compound₂O₃(ZnO)₃(grain size: 4.0 μm or less), In₂O₃And SnO₂[ In/(In + Zn): 0.93, Sn/(In + Zn + Sn): 0.08, and the relative density was 98%]The resulting sintered body was used as a sputtering target, and a transparent conductive oxide thin film was prepared on the thin film by sputtering. Thereby preparing a transparent conductive film.

That is, the polyester film was fixed to an RF sputtering apparatus, and the pressure in the vacuum chamber was reduced to 1X 10^-3Pa or less. Then, argon (purity: 99.99%) and argon [ oxygen concentration: 0.28%]So that the pressure is 1X 10^-1Pa (partial pressure of oxygen: 2.8X 10^-4Pa) is added. At an RF output of 1.2W/cm²And a substrate temperature of 200 ℃ to form a transparent conductive oxide film having a thickness of 250 nm.

(2) Evaluation of transparent conductive film

Film thickness

The film thickness of the obtained transparent conductive oxide thin film was measured using DEKTAK 3030 (manufactured by Sloan corporation) according to the tracer method.

X-ray diffraction analysis

The transparent conductive oxide thin film was subjected to X-ray diffraction analysis using Rotor Flex RU-200B (manufactured by Rigaku International Corp.). The results demonstrate that the transparent conductive oxide thin film is amorphous.

Analysis of inductively coupled plasma emission spectrum

The atomic ratios In/(In + Zn) and Sn/(In + Zn + Sn) In the transparent conductive oxide thin film were measured using an inductively coupled plasma emission spectrometry apparatus SPS-1500VR (manufactured by Seiko instruments Inc.).

The results demonstrated that the atomic ratios In/(In + Zn) and Sn/(In + Zn + Sn) were 0.93 and 0.08, respectively.

UV spectrometry

The light transmittance (wavelength: 500 or 550 nm) of the transparent conductive oxide film was measured using a UV spectrum measuring device U-3210 (manufactured by Hitachi Ltd.).

Surface resistance and resistivity

The surface resistance (initial surface resistance) of the transparent conductive oxide thin film was measured using a resistance measuring device Lorestor FP (manufactured by Mitsubishi Chemical Corp.), and the resistivity thereof was measured by a four-terminal method (initial resistivity R)₀)。

As a result, the initial surface resistance was 10.4. omega./□, and the initial resistivity (R)₀) Is 2.6X 10^-4Ω·cm。

Mobility of the support

The mobility of the carrier was measured using a device restist 8200 (a measuring device based on the Van der Pauw method, manufactured by Toyo technical cppany) for measuring hall parameters. The results demonstrated that the mobility of the support in the transparent conductive oxide thin film was 27cm²/V·sec。

(Heat resistance) test

The obtained transparent conductive film was divided into two pieces. One of which was used to perform the thermal resistance test.

That is, the transparent conductive film was left to stand in an atmosphere of 90 ℃ for 1,000 hours. Then measuring the resistivity (R) of the transparent conductive oxide film₁₀₀₀)。

The rate of change of resistance (defined as the resistivity (R) after the thermal resistance test) was calculated₁₀₀₀) And initial resistivity (R)₀) Ratio of (A to (B) ([ R))₁₀₀₀/R₀]). As a result, the rate of change was as low as 1.10.

Evaluation of etching Property

For another transparent conductive film, an aqueous solution having an oxalic acid concentration of 5 wt% and a temperature of 40 ℃ was used as an etching solution to evaluate its etching performance. The results demonstrated that the etching rate (initial etching rate) of the transparent conductive oxide thin film was 0.2 μm/min.

[ example 10]

A conductive transparent glass was obtained in the same manner as in example 9, except that #7059 manufactured by Corning inc. The film formation conditions and the atomic ratio of the metals constituting the transparent conductive oxide thin film are shown in table 5.

The evaluation results of the transparent conductive oxide film in the conductive transparent glass thus obtained are shown in table 6.

The conductive transparent glass obtained here was divided into 3 samples. Two of them were used to measure the initial resistivity (R) of the transparent conductive oxide thin film in the same manner as in example 9₀) Carrier mobility, rate of change of resistance and initial etch rate.

The remaining one piece of the sample was heated at 200 ℃ for 1 hour, and then the surface resistance and the etching rate of the transparent conductive oxide thin film were measured in the same manner as in example 9. The resistivity of the transparent conductive oxide film after heating was calculated. The evaluation results of the transparent conductive oxide film after heating are shown in table 7.

[ example 11]

A conductive transparent glass was obtained in the same manner as in example 10, except that the temperature of the substrate was 215 ℃. The film formation conditions and the atomic ratio of the metals constituting the transparent conductive oxide thin film are shown in table 5.

In addition, the evaluation results of the transparent conductive oxide film after heating are listed in table 7.

[ example 12]

The same polyester film as In example 9 was used as a transparent substrate, and In which a hexagonal layered compound was used₂O₃(ZnO)₃(grain size: 3.8 μm or less), In₂O₃And SnO₂[ In/(In + Zn): 0.96, Sn/(In + Zn + Sn): 0.18, relative density 97%]The resulting sintered body was used as a sputtering target. Thereby preparing a transparent conductive film.

Except that argon (purity: 99.99%) and oxygen were added [ oxygen concentration: 0.50%]So that the pressure is 1X 10^-1Pa (partial pressure of oxygen: 5X 10)^-4Pa), a transparent conductive oxide film was formed on the polyester film in the same manner as in example 9. The film formation conditions and the atomic ratio of the metals constituting the transparent conductive oxide thin film are shown in table 5.

The evaluation results of the transparent conductive oxide thin film in the obtained conductive transparent glass are shown in table 6.

[ example 13]

A conductive transparent glass was prepared in the same manner as in example 12, except that the same alkali-free glass substrate as that in example 10 was used as the transparent substrate. The film formation conditions and the atomic ratio of the metals constituting the transparent conductive oxide thin film are shown in table 5.

[ example 14]

A conductive transparent glass was prepared in the same manner as in example 9, except that the same alkali-free glass substrate as in example 10 was used as the transparent glassA substrate, and In is a hexagonal layered compound₂O₃(ZnO)₃(grain size: 3.6 μm), In₂O₃And SnO₂[ In/(In + Zn): 0.91, Sn/(In + Zn + Sn): 0.10, relative density 97%]The resulting sintered body was used as a sputtering target. The film formation conditions and the atomic ratio of the metals constituting the transparent conductive oxide thin film are shown in table 5.

[ example 15]

The same polyester film as in example 9 was used as a transparent substrate. An epoxy resin layer having a thickness of 1 μm was provided on the surface thereof by spin coating. The epoxy resin is photo-cured by UV-irradiation to form a crosslinked resin layer.

Next, in the same manner as in example 14, a transparent conductive oxide film was disposed on the crosslinked resin layer. Thus, the thickness is a conductive transparent film. The film formation conditions and the atomic ratio of the metals constituting the transparent conductive oxide thin film are shown in table 5.

[ example 16]

The same polyester film as In example 9 was used as a transparent substrate, and In which a hexagonal layered compound was used₂O₃(ZnO)₃(grain size: 3.8 μm), In₂O₃And SnO₂[ In/(In + Zn): 0.95, Sn/(In + Zn + Sn): 0.10, relative density 98%]The resulting sintered body was used as a sputtering target. Thereby preparing a transparent conductive film. Conditions and compositions of film formationThe atomic ratio of the metals of the bright conductive oxide film is shown in table 5.

[ example 17]

The same polyester film as in example 9 was used as a transparent substrate. A silicon dioxide layer having a thickness of 100 nm was formed thereon by an electron beam evaporation method. Next, a transparent conductive oxide film was provided on the silica resin layer in the same manner as in example 12. Thus, a transparent conductive film was prepared.

The film formation conditions and the atomic ratio of the metals constituting the transparent conductive oxide thin film are shown in table 5.

[ example 18]

A conductive transparent glass was obtained in the same manner as in example 9, except that the same alkali-free glass substrate as in example 10 was used as the transparent substrate, the temperature of the glass substrate was 215 ℃ and the oxygen content in the mixed gas at the time of sputtering was 3% (oxygen partial pressure: 3X 10)^-3Pa)。

[ comparative example 8]

A conductive transparent glass was prepared In the same manner as In example 9, except that the same alkali-free glass substrate as In example 10 was used as the transparent substrate, and In was used₂O₃(ZnO)₃Hexagonal layered compound (grain size: 12 μm) and In₂O₃[ In/(In + Zn): 0.95% and relative density 80%]The resulting sintered body was used as a sputtering target.

The obtained conductive transparent glass was evaluated in the same manner as in example 9. The evaluation results are shown in Table 6.

It was confirmed from the X-ray diffraction analysis result that indium oxide crystals were present in the transparent conductive oxide thin film after the formed transparent conductive oxide thin film was subjected to the heat treatment.

[ comparative example 9]

A conductive transparent glass was prepared In the same manner as In example 11, except that the same alkali-free glass substrate as In example 10 was used as the transparent substrate, and an ITO target [ In ] was used₂O₃/5 at.％SnO₂As a sputtering target.

In addition, the evaluation results of the conductive transparent glass are listed in table 6.

[ comparative example 10]

A conductive transparent glass was produced in the same manner as in example 11, except that the same alkali-free glass substrate as in example 10 was used as the transparent substrate, and a transparent glass composed of hexagonal crystals was usedLayered compound In₂O₃(ZnO)₃(grain size: 8 μm or less), In₂O₃And SnO₂[ In/(In + Zn): 0.98, Sn/(In + Zn + Sn): 0.05%, relative density 94%]The resulting sintered body was used as a sputtering target.

TABLE 5

		Base material	Substrate temperature (. degree.C.)	Partial pressure of oxygen (Pa)	In/(In+Zn)	Sn/(In+Zn+Sn)	Film thickness (nm)
		Base material	Substrate temperature (. degree.C.)	Partial pressure of oxygen (Pa)	In/(In+Zn)	Sn/(In+Zn+Sn)	Film thickness (nm)	Examples	9	PET	20	2.8×10^-4	0.93	0.08	250
10	Glass	20	2.8×10^-4	0.93	0.08	200			9	PET	20	2.8×10^-4	0.93	0.08	250
10	Glass	20	2.8×10^-4	0.93	0.08	200	11		Glass	215	2.8×10^-4	0.93	0.08	100
12	PET	20	5.0×10^-4	0.96	0.18	300	11		Glass	215	2.8×10^-4	0.93	0.08	100
12	PET	20	5.0×10^-4	0.96	0.18	300	13		Glass	20	5.0×10^-4	0.96	0.18	250
14	Glass	20	5.0×10^-4	0.91	0.10	210	13		Glass	20	5.0×10^-4	0.96	0.18	250
14	Glass	20	5.0×10^-4	0.91	0.10	210	15		PET	20	5.0×10^-4	0.91	0.10	200
16	PET	20	1.0×10^-4	0.95	0.10	100	15		PET	20	5.0×10^-4	0.91	0.10	200
16	PET	20	1.0×10^-4	0.95	0.10	100	17		PET	20	5.0×10^-4	0.95	0.10	100
18	Glass	215	3.0×10^-4	0.95	0.10	100	17		PET	20	5.0×10^-4	0.95	0.10	100
18	Glass	215	3.0×10^-4	0.95	0.10	100	Comparative examples		8	Glass	215	2.8×10^-4	0.95	-	100
9	Glass	20	2.8×10^-4	1.00	0.05	100			8	Glass	215	2.8×10^-4	0.95	-	100
9	Glass	20	2.8×10^-4	1.00	0.05	100		10	Glass	215	2.8×10^-4	0.98	0.05	100

TABLE 6

		Light transmittance (%)	Initial surface resistance (omega/□)	Initial resistivity (. times.10)^-4Ωcm)	Fluidity (cm)²/V·sec)	Rate of change of resistance	Etching Rate (. mu.m/min)
		Light transmittance (%)	Initial surface resistance (omega/□)	Initial resistivity (. times.10)^-4Ωcm)	Fluidity (cm)²/V·sec)	Rate of change of resistance	Etching Rate (. mu.m/min)	Examples	9	88	10.4	2.6	27	1.10	0.20
10	89	12.5	2.5	20	1.12	0.20			9	88	10.4	2.6	27	1.10	0.20
10	89	12.5	2.5	20	1.12	0.20	11		91	19.0	1.9	31	1.27	0.19
12	87	9.3	2.8	25	1.29	0.18	11		91	19.0	1.9	31	1.27	0.19
12	87	9.3	2.8	25	1.29	0.18	13		89	10.8	2.7	27	1.18	0.18
14	89	12.8	2.7	28	1.18	0.19	13		89	10.8	2.7	27	1.18	0.18
14	89	12.8	2.7	28	1.18	0.19	15		88	14.0	2.8	28	1.14	0.19
16	89	24.0	2.4	20	1.15	0.19	15		88	14.0	2.8	28	1.14	0.19
16	89	24.0	2.4	20	1.15	0.19	17		88	22.0	2.2	31	1.11	0.19
18	91	18.0	1.8	34	1.05	0.17	17		88	22.0	2.2	31	1.11	0.19
18	91	18.0	1.8	34	1.05	0.17	Comparative examples		8	79	43.2	4.3	18	1.14	Can not be etched
9	89	17.5	1.8	32	-	Can not be etched			8	79	43.2	4.3	18	1.14	Can not be etched
9	89	17.5	1.8	32	-	Can not be etched		10	89	640	64.0	-	-	Can not be etched

TABLE 7

		Initial surface resistance (omega/□)	Initial resistivity (. times.10)^-4Ωcm)	Etching Rate (. mu.m/min)
		Initial surface resistance (omega/□)	Initial resistivity (. times.10)^-4Ωcm)	Etching Rate (. mu.m/min)	Examples	9	-	-	-
10	10.0	7.0	0.19			9	-	-	-
10	10.0	7.0	0.19	11		19.0	1.9	0.18
12	-	-	-	11		19.0	1.9	0.18
12	-	-	-	13		8.4	2.1	0.18
14	9.0	1.9	0.18	13		8.4	2.1	0.18
14	9.0	1.9	0.18	15		-	-	-
16	-	-	-	15		-	-	-
16	-	-	-	17		-	-	-
18	18.0	1.8	0.17	17		-	-	-

[ example 19]

(1) Preparation of transparent conductive material

Indium oxide powder having an average particle size of 1 μm, zinc oxide having an average particle size of 1 μm and tin oxide powder having an average particle size of 0.5 μm were fed into a wet ball mill in such proportions that indium oxide, zinc oxide and tin oxide were 80 wt%, 5 wt% and 15 wt%, respectively. This raw material was then mixed and ground for 72 hours to obtain a fine powdery raw material.

Then, the powder was granulated, and the obtained granules were pressed into a target form. The formed body was sintered at 1,450 ℃ to obtain a sintered body.

The sintered body (grain size: 4.0 μm or less) had a relative density of 98% and a volume resistance of 0.83 m.OMEGA.cm.

The sintered body is then provided with means for fixing to a sputtering apparatus. The sintered body was used as a target. The diameter of the target used was 10.16 cm.

A transparent conductive oxide thin film was formed on an alkali-free glass substrate #7059 (manufactured by Corning inc.) by sputtering using this target. That is, the alkali-free glass substrate #7059 was fixed to an RF magnetron sputtering apparatus, and then the pressure of the vacuum chamber was reduced to 5X 10^-4Pa or less. Then, addMixed gas of argon and oxygen so that the pressure is 3X 10^-1Pa. The RF output is 100W. Sputtering was performed while keeping the substrate temperature at room temperature to produce a transparent conductive oxide film. Thereby obtaining transparent conductive glass.

(3) Evaluation of target and transparent conductive oxide film

The composition, relative density, volume resistance and crystallinity of the sintered body (target) obtained in the above (1) were evaluated. The results are shown in Table 8.

The resistivity and crystallinity obtained in the case where the sintered body (target) obtained in the above (1) was used for sputtering while keeping the temperature of the transparent substrate at room temperature and the resistivity and crystallinity obtained in the case where sputtering was performed using the same target while keeping the temperature of the transparent substrate at 200 ℃. The evaluation results are shown in Table 9.

The obtained transparent conductive oxide film was analyzed using Rotor Flex RU-200B (manufactured by rigaku international corp., ltd.) which is an X-ray diffraction analyzer. The transparent conductive oxide thin film was confirmed to be amorphous from an X-ray diffraction pattern.

The composition of the transparent conductive oxide thin film was analyzed using an inductively coupled plasma emission spectrometry apparatus SPS-1500VR (manufactured by seiko instruments inc.).

The surface resistance (referred to as initial surface resistance) of the transparent conductive oxide thin film was measured using a resistance measuring device Lorestor FP (manufactured by Mitsubishi Chemical corp., ltd.) and the resistivity thereof was measured by a four-terminal method.

Further, according to the tracer method, the film thickness of the obtained transparent conductive oxide thin film was measured using DEKTAK 3030 (manufactured by Sloan corporation).

(4) Heat treatment of transparent conductive oxide thin films

For the transparent conductive glass obtained in the above (1), the transparent conductive oxide film formed in the case where the transparent substrate temperature is room temperature is heat-treated at 280 ℃ for 1 hour, and the transparent conductive oxide film formed in the case where the transparent substrate temperature is 200 ℃ is heat-treated at 250 ℃ for 1 hour. The resistivity and crystallinity of these heat-treated transparent conductive oxide thin films were evaluated. The evaluation results are shown in Table 9.

[ examples 20 to 22]

(1) Sintered body and preparation of transparent conductive oxide thin film

In examples 20 to 22, sintered bodies were obtained in the same manner as in example 19, except that the mixing ratio of each raw material was changed as shown in Table 8.

Next, a transparent conductive oxide thin film was prepared in the same manner as in example 19 using each of the obtained sintered bodies.

The temperature of the transparent substrate at the time of sputtering was set to the temperature listed in table 9.

(2) Evaluation of sintered body and transparent conductive oxide film

The sintered body and the transparent conductive oxide thin film obtained in the above (1) were evaluated in the same manner as in example 19 (2). The results are shown in tables 8 and 9.

(3) Heat treatment of transparent conductive oxide thin films

The transparent conductive oxide film obtained in the above (1) was heat-treated in the same manner as in example 19(3), except that the change in the heat treatment temperature was as shown in Table 9. The results are shown in Table 9.

[ comparative examples 11 to 15]

(1) Sintered body and preparation of transparent conductive oxide thin film

In comparative examples 11 to 15, sintered bodies were produced in the same manner as in example 19, except that the mixing ratio of the raw materials was changed as shown in Table 8.

The raw materials used were as follows: indium oxide powder with an average particle size of 3 microns, zinc oxide with an average particle size of 3 microns and tin oxide with an average particle size of 3 microns.

Next, a transparent conductive oxide thin film was prepared in the same manner as in example 19 using the obtained sintered body.

The temperature of the transparent substrate at the time of sputtering was the temperature listed in table 9.

(2) Evaluation of sintered body and transparent conductive oxide film

(3) Heat treatment of transparent conductive oxide thin films

TABLE 8

	Examples				Comparative examples
	Examples				Comparative examples					19	20	21	22	11	12	13	14	15
	In₂O₃(% by weight)	80	84	87	88	90	90	94	90	19	20	21	22	11	12	13	14	15	78
SnO₂(% by weight)	In₂O₃(% by weight)	80	84	87	88	90	90	94	90	15	12	10	10	10	-	5	5	15	78
SnO₂(% by weight)	ZnO (% by weight)	5	4	3	2	-	10	1	5	15	12	10	10	10	-	5	5	15	7
Relative density (%)	ZnO (% by weight)	5	4	3	2	-	10	1	5	98	97	98	99	98	98	97	96	97	7
Relative density (%)	Volume resistance (m omega cm)	.83	.84	.70	.65	.87	2.4	.87	2.1	98	97	98	99	98	98	97	96	97	2.4
Target code	Volume resistance (m omega cm)	.83	.84	.70	.65	.87	2.4	.87	2.1	A4	B4	C4	D4	E4	F4	G4	H4	I4	2.4

TABLE 9

		Target code	Temperature (. degree.C.) of transparent substrate	Transparent conductive oxide thin film just after deposition		Transparent conductive oxide film after heat treatment
						Transparent conductive oxide film after heat treatment			Specific resistance (mu omega cm)	Crystallinity of the compound	Temperature of Heat treatment (. degree.C.)	Specific resistance (mu omega cm)	Crystallinity of the compound
				Examples	19	A4	At room temperature	290	Specific resistance (mu omega cm)	Crystallinity of the compound	Temperature of Heat treatment (. degree.C.)	Specific resistance (mu omega cm)	Crystallinity of the compound	Amorphous form	280	180	Crystallization of
A4	200	280	Amorphous form			A4	At room temperature	290	250	160	Crystallization of			Amorphous form	280	180	Crystallization of
A4	200	280	Amorphous form			20	B4	At room temperature	250	160	Crystallization of	280	Amorphous form	250	190	Crystallization of
21	C4	At room temperature	230		Amorphous form	20	B4	At room temperature	230	190	Crystallization of	280	Amorphous form	250	190	Crystallization of
21	C4	At room temperature	230		Amorphous form	22	D4	At room temperature	230	190	Crystallization of	260	Amorphous form	230	200	Crystallization of
Comparative examples	11	E4	At room temperature		550	22	D4	At room temperature	Amorphous form	230	180	260	Amorphous form	230	200	Crystallization of	Crystallization of
	11	E4	At room temperature	12	550	F4	200	380	Amorphous form	230	180	Amorphous form	300	1400	Amorphous form		Crystallization of
	13	G4	At room temperature	12	270	F4	200	380	Amorphous form	300	190	Amorphous form	300	1400	Amorphous form	Crystallization of
		G4	At room temperature	G4	270	200	200	Crystallization of	Amorphous form	300	190	-	-	-		Crystallization of
		14	H4	G4	At room temperature	200	200	Crystallization of	220	Amorphous form	250	-	-	-	3200	Crystallization of
	H4		H4	200	At room temperature	3600	Crystallization of	-	220	Amorphous form	250	-	-		3200	Crystallization of
	H4		15	200	I4	3600	Crystallization of	-	200	380	Amorphous form	-	-	230	370	Amorphous form

Symbol ". X" indicates the inclusion of fine crystals

[ example 23]

(1) Preparation of transparent conductive oxide thin film

Indium oxide powder having an average particle size of 1 μm, zinc oxide having an average particle size of 1 μm, and tin oxide powder having an average particle size of 0.5 μm were mixed and pulverized in a wet ball mill in percentages of 84.8 wt%, 5.2 wt%, and 10.0 wt%, respectively, of indium oxide, zinc oxide, and tin oxide. Then, the obtained powder was granulated, and the obtained granules were pressed into a target shape. The formed body was sintered at 1,450 ℃ to obtain a sintered body (grain size: 3.7 μm or less).

Then, sputtering was performed using this target. The transparent substrate was an alkali-free glass substrate #7059 (manufactured by Corning inc. The sputtering apparatus is a parallel plate type magnetron sputtering apparatus. The apparatus was evacuated to 5X 10^-5Pa. At this time, the water content in the vacuum chamber was measured using a simultaneous mass spectrometer. As a result, it was 8X 10^-6Pa。

Thereafter, argon containing 1% by volume of oxygen was used in the apparatus. The sputtering pressure was adjusted to 3X 10^-1Pa for sputtering. Thus forming a transparent conductive oxide thin film on the glass substrate. The thickness of the obtained transparent conductive oxide thin film was 1.2 nm.

In order to measure the peak binding energy of the oxygen 1S orbital by X-ray photoelectron spectroscopy, ESCA5400 manufactured by Alback company and Mg-K.alpha.as a source were used. An electrostatic hemispherical detector was used. The energy passed was 35.75 eV. 3d of indium^5/2The peak was measured at 444.4 eV. For the half-width of the peak obtained here, the baseline was determined using the Shirley equation, and the value of the half-width was calculated.

As a result, according to the XPS method, the half-width of the peak of the binding energy of the oxygen 1S orbital in the surface of the transparent conductive oxide film was 2.6 eV.

The peak of the binding energy of the oxygen 1S orbital in the surface of the transparent conductive oxide film measured based on the XPS method is shown in fig. 12.

(2) Evaluation of transparent conductive oxide film

The transparent conductive oxide thin film obtained in the above (1) was evaluated for crystallinity, light transmittance, resistivity, and etching property.

The crystallinity of the transparent conductive oxide film was examined by X-ray diffraction analysis using Rotor Flex RU-200B (manufactured by Rigaku International Corp.).

The light transmittance (wavelength: 500 or 550 nm) of the transparent conductive oxide film was measured by UV spectrometry using U-3210 (manufactured by Hitachi Ltd.).

The surface resistance of the transparent conductive oxide thin film was measured according to the four-terminal method using Lorestor FP (manufactured by Mitsubishi Chemical corp. And then its resistivity is calculated.

The etching performance was measured at 40 ℃ using an aqueous solution having an oxalic acid concentration of 3.4 wt% as an etching solution.

(3) Measuring connection resistance

Next, the transparent conductive oxide film obtained in the above (1) was etched into a strip shape having a height of 110 μm and a gap of 20 μm, and then an antistatic conductive film was placed on the strip-shaped transparent conductive oxide film and hot-pressed thereon at 180 ℃. The connection resistance between the transparent conductive oxide film and the antistatic conductive film was measured. The average value of the resistance is 8 Ω.

In order to determine the long-term stability of the connection resistance, a sample obtained by placing and hot-pressing an antistatic conductive film on a transparent conductive oxide film was left standing in an oven maintained at 95 ℃ for 120 hours, and then the connection resistance of the sample was measured again. In this sample, no change in connection resistance was found even after a long heat treatment.

The composition of the obtained transparent conductive oxide thin film and the evaluation results are listed in table 10.

[ example 24]

A target and a transparent conductive oxide thin film were prepared and formed in the same manner as in example 23, except that the mixing ratio of the metal oxides was changed as follows: 87.3% by weight indium oxide, 9.5% by weight tin oxide and 3.2% by weight zinc oxide. In this case, the water content in the vacuum chamber was 7X 10^-6Pa。

According to the XPS method, the half-peak width of the binding energy peak of the oxygen 1S orbital in the obtained transparent conductive oxide thin film was measured. It is 2.5 eV.

[ example 25]

A target and a transparent conductive oxide thin film were prepared and formed in the same manner as in example 23, except that the mixing ratio of the metal oxides was changed as follows: 81.6% by weight indium oxide, 12.2% by weight tin oxide and 6.2% by weight zinc oxide. In this case, the water content in the vacuum chamber was 9X 10^-6Pa。

According to the XPS method, the half-peak width of the binding energy peak of the oxygen 1S orbital in the obtained transparent conductive oxide thin film was measured, which was 2.7 eV. The composition of the obtained transparent conductive oxide thin film and the evaluation results are listed in table 10.

[ comparative example 16]

A target (crystal grain diameter: 15 μm) was prepared and a transparent conductive oxide thin film was formed in the same manner as in example 23, except that indium oxide powder having an average particle size of 3 μm, tin oxide powder having an average particle size of 3 μm, and zinc oxide powder having an average particle size of 3 μm were used, and the mixing ratio thereof was changed as follows: 88.7% by weight indium oxide, 10.1% by weight tin oxide and 1.2% by weight zinc oxide.

In this case, the water content in the vacuum chamber was 9X 10^-6Pa。

According to the XPS method, the half-peak width of the binding energy peak of the oxygen 1S orbital in the obtained transparent conductive oxide thin film was measured. It is 2.9 eV.

The etching rate of the transparent conductive oxide film obtained here was as low as 4.4 a/sec.

The composition of the transparent conductive oxide film and the evaluation results are shown in table 10.

[ comparative example 17]

A target (crystal grain diameter: 11 μm) was prepared in the same manner as in example 23, except that indium oxide powder having an average particle size of 3 μm, tin oxide powder having an average particle size of 3 μm, and zinc oxide powder having an average particle size of 3 μm were used, and the mixing ratio thereof was changed as follows: 84.8% by weight indium oxide, 10.0% by weight tin oxide and 5.2% by weight zinc oxide.

Then, the vacuum chamber was evacuated to 2X 10 at the start of sputtering^-5Pa. The pressure was adjusted to 3X 10 using argon containing 1% by volume of oxygen^-1Pa. The water content in the vacuum chamber was then adjusted to 9X 10^-4Pa. Except for these operations, a transparent conductive oxide film was formed in the same manner as in example 23.

The half-width of the binding energy peak of the oxygen 1S orbital in the obtained transparent conductive oxide film was 3.3 eV.

The obtained transparent conductive oxide film was heat-treated at 95 ℃ for 120 hours. As a result, the connection resistance is significantly increased.

[ comparative example 18]

A target (crystal grain diameter: 14 μm) was prepared and a transparent conductive oxide thin film was formed in the same manner as in example 23, except that indium oxide powder having an average particle size of 3 μm, tin oxide powder having an average particle size of 3 μm, and zinc oxide powder having an average particle size of 3 μm were used, and the mixing ratio thereof was changed as follows: 83.4% by weight indium oxide, 4.3% by weight tin oxide and 12.3% by weight zinc oxide. In this case, the water content in the vacuum chamber is 1X 10^-7Pa。

The half-width of the binding energy peak of the oxygen 1S orbital in the obtained transparent conductive oxide film was 3.8 eV. The binding energy peak of the oxygen 1S orbital in the surface of the transparent conductive oxide thin film measured according to the XPS method is shown in FIG. 13.

[ comparative example 19]

A target (crystal grain diameter: 18 μm) was prepared in the same manner as in example 23, except that indium oxide powder having an average particle size of 3 μm and tin oxide powder having an average particle size of 3 μm were used, and the mixing ratio thereof was changed as follows: 90.0 wt.% indium oxide and 10.0 wt.% tin oxide.

The half-width of the binding energy peak of the oxygen 1S orbital in the obtained transparent conductive oxide film was 3.4 eV.

Watch 10

		Examples			Comparative examples
		Examples			Comparative examples				23	24	25	16	17	18	19
		Composition of	In₂O₃(% by weight)	84.8	87.3	81.6	88.7	84.8	23	24	25	16	17	18	19	83.4	90.0
SnO₂(% by weight)	10.0		In₂O₃(% by weight)	84.8	87.3	81.6	88.7	84.8	9.5	12.2	10.1	10.0	4.3	10.0		83.4	90.0
SnO₂(% by weight)	10.0		ZnO (% by weight)	5.2	3.2	6.2	1.2	5.2	9.5	12.2	10.1	10.0	4.3	10.0	12.3	-
Water content (. times.10)^-6Pa)			ZnO (% by weight)	5.2	3.2	6.2	1.2	5.2	8	7	9	9	20	0.1	12.3	-	900
Water content (. times.10)^-6Pa)		Half peak width (Ev)		2.6	2.5	2.7	2.9	3.3	8	7	9	9	20	0.1	3.8	3.4	900
Evaluation of crystals		Half peak width (Ev)		2.6	2.5	2.7	2.9	3.3	Amorphous form	Amorphous form	Amorphous form	Amorphous form	Amorphous form	Amorphous form	3.8	3.4	Amorphous form
Evaluation of crystals		Light transmittance (%)		81	81	82	81	81	Amorphous form	Amorphous form	Amorphous form	Amorphous form	Amorphous form	Amorphous form	80	81	Amorphous form
Resistivity (μ Ω m)		Light transmittance (%)		81	81	82	81	81	240	220	240	280	490	370	80	81	560
Resistivity (μ Ω m)		Etching Rate (. mu.m/60 sec.)		0.09	0.06	0.09	0.03	0.10	240	220	240	280	490	370	0.11	0.06	560
Initial contact resistance (omega)		Etching Rate (. mu.m/60 sec.)		0.09	0.06	0.09	0.03	0.10	8	10	12	11	14	16	0.11	0.06	34
Initial contact resistance (omega)		Contact resistance after heat treatment (omega)		8	10	12	11	38	8	10	12	11	14	16	54	78	34

"amorphous" in the evaluation of the crystals means an amorphous state.

[ example 26]

(1) Forming an organic colored layer on a substrate

A glass substrate was used as a substrate on the surface of which a light-shielding layer made of chromium oxide was formed. The light shield layer is preferably formed by sputtering, and the thickness of the chromium oxide layer is 0.1 μm.

Next, the light-shielding layer was processed into a mesh with a line width of 30 μm by photolithography. The pitch along one direction was 110 microns and the pitch along the direction perpendicular to that direction was 330 microns.

Then, a phthalocyanine green pigment (pigment green 36 having a color index of 74160) was used as a green pigment, and dispersed and mixed in a transparent polyimide precursor solution, Semicofine SP-910(Toray Industries, Inc), and the obtained slurry was coated on a mesh-shaped chromium oxide layer. It was semi-cured to form a stripe-shaped green organic colored layer having a width of 90 μm and a height of 330 μm, which corresponded to a pixel. And then cured. The thickness of the green organic coloured layer was 1.5 microns.

Quinacridone (color index 73905, pigment Red 209) is used as the red pigment and phthalocyanine blue pigment (color index 74160, pigment blue 15-4) is used as the blue pigment. The red organic coloring layer and the blue organic coloring layer are formed in the same manner as described above by a slurry obtained by dispersing or mixing them in the above polyimide precursor solution, respectively.

The above polyimide precursor solution was coated on these organic colored layers, and these coatings were cured to form a protective layer 2 μm thick.

(2) Formation of transparent conductive film

A transparent conductive film (transparent conductive oxide film) was formed on the organic colored layer of the glass substrate having the organic colored layer obtained in the above (1) by sputtering.

The sputtering target used herein was prepared as follows. That is, a mixture of 80 wt% indium oxide powder, 15 wt% tin oxide powder and 5 wt% zinc oxide powder was mixed and pulverized in a wet ball mill. The powder obtained is then granulated and the granules obtained are subsequently press-formed. It was sintered in a sintering furnace at 1,450 ℃ for 36 hours under compressed oxygen to obtain a target having a grain size of 4.0 μm [ A6 ].

The obtained sputtering target [ a6] was fixed on a DC magnetron sputtering apparatus, and then a transparent conductive film was formed on the organic colored layer of the glass substrate by sputtering.

The sputtering conditions in this case were that argon gas mixed with an appropriate amount of oxygen was used as the ambient atmosphere and the sputtering pressure was 3X 10^-1Pa, the final pressure reached is 5X 10^-4Pa, the substrate temperature was 25 ℃, the applied electric power was 100W, and the film formation time was 20 minutes.

As a result, a transparent conductive glass in which a thin film having a film thickness of about 120 nm was formed on the organic coloring layer was obtained.

The crystallinity of the transparent conductive film was observed by X-ray diffraction analysis. The results demonstrate that the film is amorphous.

When a transparent conductive surface was formed on the organic colored layer of another glass substrate, the substrate temperature at the time of sputtering was set to 180 ℃. The transparent conductive surface is also amorphous.

The composition and physical properties of the transparent conductive film are shown in Table 11.

(3) Evaluation of etching Properties of transparent conductive film

The etching performance of the obtained transparent conductive film was evaluated.

That is, a part of the transparent conductive film formed on the organic coloring layer was etched at 40 ℃ using an oxalic acid aqueous solution (concentration: 5 wt%), and then the cross-sectional shape of the boundary portion between the etched portion and the unetched portion was observed using an electron microscope.

As a result, it was found that no transparent conductive film remained in the etched portion, and the edge portion of the transparent conductive oxide film remained in the unetched portion had a sectional shape smoothly inclined toward the etched portion.

It was thus confirmed that the obtained transparent conductive oxide thin film had good processability even when etching was performed using a weak acid.

In evaluating the etching processability of the transparent conductive film, the evaluation criteria described in example 4 were employed. The evaluation results are shown in Table 2.

(4) Crystallinity of heat-treated transparent conductive film

Next, the transparent conductive film formed on the organic colored layer of the glass substrate obtained in the above (2) is heat-treated.

The heat treatment in this case was carried out under an argon atmosphere by heating the film to 230 ℃ at a temperature rising rate of 20 ℃/min and holding the film at that temperature for 1 hour.

The transparent conductive film subjected to the heat treatment was crystallized, and its resistivity was 230X 10 as measured by the four-probe method^-6Ω.cm。

Further, as for the transparency of the transparent conductive oxide film, the light transmittance according to a spectrometer for light having a wavelength of 500 nm was 82%. Therefore, the transparency is also excellent.

No adverse effects due to the heat treatment, such as heat aging of the organic colored layer, were observed.

[ example 27]

(1) Preparation of transparent conductive film

Target [ B6] (crystal grain size: 4.0 μm) was prepared in the same manner as in example 26(2), but on the organic colored layer of the glass substrate having an organic colored layer obtained in the same manner as in example 26(1), a mixture of 84% by weight of indium oxide powder, 12% by weight of tin oxide powder and 4% by weight of zinc oxide powder was used as a raw material of a sputtering target. The transparent conductive film is produced using the target.

The composition and physical properties thereof are shown in Table 11.

(2) Evaluation of etching Properties of the transparent conductive film

The etching performance of the transparent conductive film obtained in the above (1) was evaluated in the same manner as in example 26 (3). The results are shown in Table 12.

(3) Crystallinity of heat-treated transparent conductive film and evaluation of the transparent conductive film

Next, heat treatment of the transparent conductive film obtained in the above (1) was performed in the same manner as in example 26(4) to form a transparent conductive film. The results are shown in Table 12.

[ example 28]

(1) Preparation of transparent conductive film

Target [ C6] (crystal grain size: 4.1 μm) was prepared in the same manner as in example 26(2), but on the organic colored layer of the glass substrate having an organic colored layer obtained in the same manner as in example 26(1), a mixture of 87% by weight of indium oxide powder, 10% by weight of tin oxide powder and 2% by weight of zinc oxide powder was used as a raw material of a sputtering target. The transparent conductive film is produced using the target.

The composition and physical properties thereof are shown in Table 11.

(2) Evaluation of etching Properties of the transparent conductive film

(3) Crystallinity of heat-treated transparent conductive film

[ example 29]

(1) Preparation of transparent conductive film

A target [ D6] (crystal grain diameter: 4.0 μm) was prepared in the same manner as in example 26(2), but on the organic colored layer of the glass substrate having an organic colored layer obtained in the same manner as in example 26(1), a mixture of 88% by weight of indium oxide powder, 10% by weight of tin oxide powder and 2% by weight of zinc oxide powder was used as a raw material of a sputtering target. The transparent conductive film is produced using the target.

The composition and physical properties thereof are shown in Table 11.

(2) Evaluation of etching Properties of the transparent conductive film

(3) Crystallinity of heat-treated transparent conductive film

[ comparative example 20]

(1) Preparation of transparent conductive film

Target [ E6] (crystal grain diameter: 1.2 μm) was prepared from a mixture of 90% by weight of indium oxide powder, 10% by weight of tin oxide powder and no zinc oxide powder, and a transparent conductive film was formed on the organic colored layer of the glass substrate having an organic colored layer obtained in the same manner as in example 26 (1).

The composition and physical properties thereof are shown in Table 11.

(2) Evaluation of etching Properties of the transparent conductive film

(3) Heat treatment of transparent conductive film

[ comparative example 21]

(1) Preparation of transparent conductive film

A target [ F6] (crystal grain diameter: 18 μm) was prepared in the same manner as in example 26(2), but on the organic colored layer of the glass substrate having an organic colored layer obtained in the same manner as in example 26(1), a mixture of 90% by weight of indium oxide powder and 10% by weight of zinc oxide powder was used as a raw material of a sputtering target. The transparent conductive film is produced using the target.

The crystallinity of the transparent conductive film obtained here was observed using X-ray diffraction analysis. As a result it is amorphous. The composition and physical properties thereof are shown in Table 11.

(2) Evaluation of etching Properties of the transparent conductive film

(3) Heat treatment of transparent conductive films

[ comparative example 22]

(1) Preparation of transparent conductive film

A target [ G6] (crystal grain size: 15 μm) was produced in the same manner as in example 26(2), but on the organic colored layer of the glass substrate having an organic colored layer obtained in the same manner as in example 26(1), a mixture of 94% by weight of indium oxide powder having an average particle size exceeding 3 μm, 5% by weight of tin oxide having an average particle size exceeding 3 μm and 1% by weight of zinc oxide powder having an average particle size exceeding 3 μm was used as a raw material for a sputtering target. The transparent conductive film is produced using the target.

The crystallinity of the transparent conductive film obtained here was observed using X-ray diffraction analysis. As a result it is amorphous.

The transparent conductive film was prepared using this target [ G6] with the temperature of the substrate at the time of sputtering set to 200 ℃.

The obtained transparent conductive film is crystalline. The composition and physical properties thereof are shown in Table 11.

(2) Evaluation of etching Properties of the transparent conductive film

(3) Heat treatment of transparent conductive films

Next, the transparent conductive film prepared by setting the substrate temperature to room temperature was subjected to heat treatment in the same manner as in example 26(4) to form a transparent conductive film. The results are shown in Table 12.

[ comparative example 23]

(1) Preparation of transparent conductive film

A target [ H6] (crystal grain diameter: 17 μm) was prepared using a mixture of 90% by weight of indium oxide powder having an average particle size exceeding 3 μm, 5% by weight of tin oxide powder having an average particle size exceeding 3 μm and 5% by weight of zinc oxide powder having an average particle size exceeding 3 μm, and a transparent conductive film was prepared using this target on the organic colored layer of the glass substrate having an organic colored layer obtained in the same manner as in example 26 (1).

The transparent conductive film was prepared using this target [ H6] with the temperature of the substrate at the time of sputtering set to 200 ℃.

(2) Evaluation of etching Properties of the transparent conductive film

(3) Heat treatment of transparent conductive films

Next, the transparent conductive film prepared by setting the substrate temperature to room temperature was subjected to heat treatment in the same manner as in example 26 (4). The results are shown in Table 12.

TABLE 11

	Examples				Comparative examples
	Examples				Comparative examples				26	27	28	29	20	21	22	23
	In₂O₃(% by weight)	80	84	87	88	90	90	94	26	27	28	29	20	21	22	23	90
SnO₂(% by weight)	In₂O₃(% by weight)	80	84	87	88	90	90	94	15	12	10	10	10	-	5	5	90
SnO₂(% by weight)	ZnO (% by weight)	5	4	3	2	-	10	1	15	12	10	10	10	-	5	5	5
Relative density (%)	ZnO (% by weight)	5	4	3	2	-	10	1	98	97	98	99	98	98	97	96	5
Relative density (%)	Volume resistance (m omega cm)	0.83	0.84	0.70	0.65	0.87	2.43	0.87	98	97	98	99	98	98	97	96	2.1
Target code	Volume resistance (m omega cm)	0.83	0.84	0.70	0.65	0.87	2.43	0.87	A6	B6	C6	D6	E6	F6	G6	H6	2.1

TABLE 12

		Target code	Substrate temperature (. degree.C.)	Transparent conductive film after setting			Transparent conductive film after heat treatment
				Transparent conductive film after setting			Transparent conductive film after heat treatment			Specific resistance (mu omega cm)	Evaluation of crystals	Etching performance	Temperature (. degree.C.)	Specific resistance (mu omega cm)	Evaluation of crystals
				Examples	26	A6	At room temperature	290	Amorphous form	Specific resistance (mu omega cm)	Evaluation of crystals	Etching performance	Temperature (. degree.C.)	Specific resistance (mu omega cm)	Evaluation of crystals	○	230	230	Crystallization of
A6	180	280	Amorphous form			A6	At room temperature	290	Amorphous form	○	230	210	Crystallization of			○	230	230	Crystallization of
A6	180	280	Amorphous form			27	B6	At room temperature	280	○	230	210	Crystallization of	Amorphous form	○	230	220	Crystallization of
28	C6	At room temperature	230		Amorphous form	27	B6	At room temperature	280	○	230	210	Crystallization of	Amorphous form	○	230	220	Crystallization of
28	C6	At room temperature	230		Amorphous form	29	D6	At room temperature	260	○	230	210	Crystallization of	Amorphous form	○	250	200	Crystallization of
Comparative examples	20	E6	At room temperature		550	29	D6	At room temperature	260	Amorphous form	△	230	180	Amorphous form	○	250	200	Crystallization of	Crystallization of
	20	E6	At room temperature	21	550	F6	200	380	Amorphous form	Amorphous form	△	230	180	○	250	370	Amorphous form		Crystallization of
	22	G6	At room temperature	21	270	F6	200	380	Amorphous form	Amorphous form	△	250	230	○	250	370	Amorphous form	Crystallization of
		G6	At room temperature	G6	270	200	200	Crystallization of	×	Amorphous form	△	250	230	-	-	-		Crystallization of
		23	H6	G6	At room temperature	200	200	Crystallization of	×	220	Amorphous form	△	250	-	-	-	3200	Crystallization of
	H6		H6	200	At room temperature	3600	Crystallization of	×	-	220	Amorphous form	△	250	-	-		3200	Crystallization of

"amorphous" in the evaluation of the crystals means the amorphous state

"crystalline" in the evaluation of crystals means the crystalline state

Industrial applicability

As described above in detail, according to the sputtering target of the present invention, it is possible to effectively suppress generation of the spherical objects by controlling the grain diameter thereof to a given value or more when the transparent conductive oxide is made into a thin film by sputtering. Therefore, the sputtering can be stably performed for a long time.

According to the method for producing a sputtering target of the present invention, it is possible to effectively provide a target capable of suppressing generation of spherical objects when a transparent conductive oxide is formed into a thin film.

According to the transparent conductive oxide of the present invention, excellent conductivity and transparency can be obtained, and further smooth surface properties can be obtained.

Claims

1. A sputtering target comprising at least indium oxide and zinc oxide, wherein the atomic ratio represented by In/(In + Zn) is 0.75 to 0.97, including₂O₃(ZnO)_mThe hexagonal layered compound represented by (1), wherein m is a positive integer of 2 to 20, and the grain size of the hexagonal layered compound is 5 μm or less.

2. The sputtering target of claim 1, wherein the indium oxide is 67 to 93% by weight, the tin oxide is 5 to 25% by weight, and the zinc oxide is 2 to 8% by weight, and the atomic ratio of tin to zinc is 1 or higher.

3. The sputtering target of claim 1 or 2, comprising Zn₂SnO₄The spinel-structured compound is shown in place of the hexagonal layered compound or includes the spinel-structured compound and the hexagonal layered compound, and the grain diameter of the spinel-structured compound is set to 5 μm or less.

4. Sputtering target according to claim 1 or 2, having a volume resistivity of less than 1 x 10^-3Ω·cm。

5. The sputtering target of claim 3 having a volume resistivity of less than 1 x 10^-3Ω·cm。

6. The sputtering target of any one of claims 1,2 or 5, which has a density of 6.7g/cm³Or higher.

7. The sputtering target of claim 3, which has a density of 6.7g/cm³Or higher.

8. The sputtering target of claim 4, which has a density of 6.7g/cm³Or higher.

9. A transparent conductive oxide containing a sputtering target, wherein the atomic ratio expressed by In/(In + Zn) is 0.75 to 0.97, including₂O₃(ZnO)_mThe hexagonal layered compound represented by (1), wherein m is a positive integer of 2 to 20, and the grain diameter of the hexagonal layered compound is set to 5 μm or less.

10. The transparent conductive oxide according to claim 9, wherein the indium oxide is included in a sputtering target in an amount of 67 to 93% by weight, the tin oxide is included in an amount of 5 to 25% by weight, and the zinc oxide is included in an amount of 2 to 8% by weight, and the atomic ratio of tin to zinc is 1 or more.

11. The transparent conductive oxide according to claim 9 or 10, wherein the transparent conductive oxide is crystallized at a temperature of 230 ℃ or more.

12. The transparent conductive oxide according to any one of claims 9 or 10, wherein the half-width of the binding energy peak of the oxygen 1S orbital determined by X-ray photoelectron spectroscopy is 3eV or less.

13. The transparent conductive oxide according to claim 11, wherein the half width of the peak of the binding energy of the oxygen 1S orbital determined by X-ray photoelectron spectroscopy is 3eV or less.

14. The transparent conductive oxide according to any one of claims 9, 10, or 13, wherein the transparent conductive oxide is formed on a substrate or on a colored layer provided on the substrate.

15. The transparent conductive oxide according to claim 11, wherein the transparent conductive oxide is formed on a substrate or a colored layer provided on the substrate.

16. The transparent conductive oxide according to claim 12, wherein the transparent conductive oxide is formed on a substrate or on a colored layer provided on the substrate.

17. The transparent conductive oxide according to any one of claims 9, 10, 13, 15, or 16, wherein the P-V value measured according to JIS B0601 is 1 μm or less.

18. The transparent conductive oxide according to claim 11, wherein the P-V value measured according to JIS B0601 is 1 μm or less.

19. The transparent conductive oxide according to claim 12, wherein the P-V value measured according to JIS B0601 is 1 μm or less.

20. The transparent conductive oxide according to claim 14, wherein the P-V value measured according to JIS B0601 is 1 μm or less.

21. A method of making a sputter target comprising In₂O₃(ZnO)_mA hexagonal layered compound represented by (1) wherein m is a positive integer of 2 to 20, the grain diameter of the hexagonal layered compound being set to 5 μm or less, the method comprising steps (1) to (3):

(3) the formed body is sintered at a temperature of 1400 ℃ or higher, under an oxygen atmosphere or under compressed oxygen.

22. The method for producing a sputtering target according to claim 21, wherein 67 to 93% by weight of the indium oxide powder, 5 to 25% by weight of the tin oxide powder, and 2 to 8% by weight of the zinc oxide powder are mixed in step (1), and a compact having a tin-to-zinc atomic ratio of 1 or more is produced in step (2).

23. A method of making a sputter target comprising In₂O₃(ZnO)_mA hexagonal layered compound represented by (i) wherein m is a positive integer of 2 to 20, the hexagonal layered compound having a crystal grain diameter of 5 μm or less, the method comprising steps (1) to (5):

(1) preparation of In₂O₃(ZnO)_mA hexagonal layered compound represented by (I), wherein m is a positive integer of 2 to 20,

(5) the formed body is sintered at a temperature of 1400 ℃ or higher, under an oxygen atmosphere or under compressed oxygen.

24. The method of making a sputtering target according to any one of claims 21 or 22, wherein the average particle size of the indium oxide powder is 0.1 to 2 μm.

25. The method of making a sputtering target according to claim 23, wherein the average particle size of the indium oxide powder is 0.1 to 2 microns.

26. The method for producing a sputtering target according to any one of claims 21 or 22, wherein a tin oxide powder is further mixed together with the indium oxide powder, and the average particle size of the tin oxide powder is 0.01 to 1 μm.

27. The method for producing a sputtering target according to any one of claims 23 or 25, wherein a tin oxide powder is further mixed together with the indium oxide powder, and the average particle size of the tin oxide powder is 0.01 to 1 μm.

28. The method of producing a sputtering target according to claim 24, wherein a tin oxide powder is further mixed together with the indium oxide powder, and the average particle size of the tin oxide powder is 0.01 to 1 μm.

29. The method for producing a sputtering target according to any one of claims 21 or 22, wherein a spinel-structured compound whose particle size is adjusted to 5 μm or less is further mixed at the time of producing the formed body.

30. The method for producing a sputtering target according to any one of claims 23, 25, or 28, wherein a spinel-structured compound whose particle size is adjusted to 5 μm or less is further mixed at the time of producing the formed body.

31. The method for producing a sputtering target according to claim 24, wherein a spinel-structured compound whose particle size is adjusted to 5 μm or less is further mixed at the time of producing the shaped body.

32. The method for producing a sputtering target according to claim 26, wherein a spinel-structured compound whose particle size is adjusted to 5 μm or less is further mixed at the time of producing the shaped body.

33. The method for producing a sputtering target according to claim 27, wherein a spinel-structured compound whose particle size is adjusted to 5 μm or less is further mixed at the time of producing the shaped body.