KR20160148593A - Ito sputtering target and method for manufacturing same, ito transparent electroconductive film, and method for manufacturing ito transparent electroconductive film - Google Patents

Abstract

A sintered body made of In, Sn, O and inevitable impurities, which contains Sn having an atomic ratio of Sn / (In + Sn) of 1.8% or more and 3.7% or less (excluding 3.7% Wherein the average pore size of the pores is in the range of 1.0 to 5.0 mu m and the major axis diameter is 0.1 to 1.0 mu m in the pore size ratio of 0.5% or less, the pore size of the indium oxide phase and the tin oxide- To 1.0%, and at least 95% of the tin oxide rich phase is present at the grain boundary triple point. A sputtering target having a low oxide tin composition and capable of obtaining a film having a low resistance even at a low temperature, which is preferable for formation of a transparent conductive film, is a sputtering target which has a small particle size, high density and high strength, and can reduce arcing and nodules .

Description

TECHNICAL FIELD [0001] The present invention relates to an ITO sputtering target, a method of manufacturing the ITO sputtering target, and a method of manufacturing an ITO transparent conductive film and an ITO transparent conductive film,

The present invention relates to an ITO sputtering target suitable for forming an ITO film. To an ITO sputtering target capable of reducing arcing and nodules, a method of manufacturing the ITO sputtering target, and a method of manufacturing an ITO transparent conductive film and an ITO transparent conductive film. The main uses of the present invention include touch panels, flat panel displays, organic EL, and solar cells.

In general, an ITO (indium-tin composite oxide) film is widely used as a transparent electrode (conductive film) in a display device centered on a liquid crystal display. This ITO film is formed by a method generally called a physical vapor deposition method such as a vacuum evaporation method or a sputtering method. In many cases, the magnetron sputtering method is used in many cases from the viewpoint of operability and stability of the coating film.

The formation of the film by the sputtering method is carried out by physically colliding cations such as Ar ions with the target provided on the cathode and discharging the material constituting the target by the collision energy so that the target material And is performed by laminating films of approximately the same composition. The coating method by the sputtering method is characterized in that it can form a thin film of several nm to a thick film of several tens of micrometers at a stable film forming speed by adjusting the processing time and the supply power.

In recent years, there has been a demand for an ITO film used in capacitance type, resistance film type touch panels and the like. In addition to the ITO sputtering target containing about 10 wt.% Of tin (Sn) widely used conventionally, Is in the range of 1.0 to 50.0 wt.%. For example, in Patent Document 1, a mixed powder of indium oxide containing tin oxide in an amount of 20 to 50 wt% is press molded, and the formed body is subjected to heat treatment in a pure oxygen atmosphere at a temperature of 1500 to 1650 DEG C, a pressure of 0.15 to 1 MPa To produce an ITO sputtering target.

Patent Literature 1 listed below has a representative patent for an ITO sputtering target. This patent discloses an ITO sputtering target produced from a raw material mainly composed of indium oxide and tin oxide by powder metallurgy and having a surface roughness Ra of 0.5 m or less and a density D (g / cm3) and a bulk resistance value p cm < 2 >) satisfy the following two equations simultaneously. a) 6.20 ≤ D ≤ 7.23, b) -0.0676D + 0.887 ≥ ρ ≥ -0.0761D + 0.666. "This is about 20 years ago.

This patent can realize an ITO sintered target which can stably obtain an ITO film with high quality under a good film forming operation because it rarely generates an abnormal discharge or nodules during sputtering and has very little gas adsorption It is a breakthrough invention at that time.

As a countermeasure for increasing the ITO target density, for example, Patent Document 2 discloses that the median diameter obtained from the particle size distribution is in the range of 0.40 (excluding 0.40) to 1.0 占 퐉, and the 90% And an ITO target formed using tin oxide powder in the range of 3.0 占 퐉 or less.

However, when such an ITO target containing more tin oxide is produced by using such a tin oxide powder, macropores and microcracks are generated inside the sintered body, and during the processing of the sintered body or storage after completion of the processing, cracks Or cracking may occur. And they sometimes affected the shipment of the product as a target.

In addition, Patent Document 3 discloses an ITO sintered body in which fine particles made of In ₄ Sn ₃ O ₁₂ exist in the In ₂ O ₃ parent phase, which is a main crystal grain, as a technology related to ITO, Discloses a technology for providing an ITO sputtering target characterized by having a star shape in which an acicular projections are formed in a radial direction from a virtual center and has a low bulk resistance.

The following Patent Document 4 discloses a sintered body made of In, Sn and O, having a sintered density of 7.08 g / cm 3 or more, a bulk resistivity of 80 μΩcm to 100 μΩcm, and an O / (In + Sn + O) (Weight ratio) of the In ₄ Sn ₃ O ₁₂ phase and not more than 30% of the integral intensity of the X-ray diffraction peak of the (200) face of the In ₄ Sn ₃ O ₁₂ phase. The sintered body is a sintered body, Discloses a technique for converting a sintering atmosphere from an oxidizing atmosphere to a non-oxidizing atmosphere when the temperature reaches 1400 占 폚 or higher.

In order to obtain a low-resistance film with ITO (tin oxide: 10 wt.%) Which is generally used, it is necessary to conduct heat treatment at 150 ° C or more, but there is also a case where heat of 150 ° C can not be applied. For example, when a transparent conductive film used in a touch panel or the like is a structural problem, ITO having a low-tin oxide composition capable of obtaining a low-resistance film even at low temperatures is used when heat can not be applied during film formation or after film formation.

The ITO target having a low tin oxide composition has a probability of existence on the tin-rich phase depending on the sintering temperature. Therefore, unless the sintering temperature is controlled, the density is not increased sufficiently and control of the crystal grain size becomes difficult. In addition, there is a case where deviation in density occurs between lots. Further, the dispersibility on the tin-rich phase is deteriorated, and problems such as nodule and arcing are liable to occur.

The following Patent Documents 5 to 10 propose an ITO sputtering target with a low-tin oxide composition.

Patent Document 5 is characterized in that the tin oxide content is 1.5% to 3.5% by mass ratio, the relative density is 98% or more, the crystal phase is single phase, the average crystal grain size is 10 占 퐉 or less, and the sintered body has a bending strength of 70 MPa or more However, since the sintering temperature is as high as 1500 ° C and the first granulation powder and the second granulation powder are mixed to produce a molded article, the productivity is not so good.

Patent Document 6 discloses a honeycomb structure comprising indium oxide, tin oxide and inevitable impurities, wherein the content of tin oxide is 2.5 mass% or more and 5.2 mass% or less, the average density is 7.1 g / cm 3 or more, The ITO sputtering target has a thickness of 10 탆 or more but less than 10 탆. However, the holding temperature is as high as 1500 to 1600 캜 and the strength of the sintered body is not described.

Patent Document 7 discloses that the tin content is 3 to 12 wt%, the solubility of tin dissolved in the In ₂ O ₃ phase is 2 wt% or more, the tin element is dissolved in the In ₂ O ₃ phase and In ₂ O ₃ phase Wherein the average crystal grain size of the sintered body is in the range of 2 to 10 mu m and the maximum pore diameter present in the sintered body is 3 mu m or less and the maximum aggregation diameter of tin atoms is 5 mu m or less However, the sintering temperature is not lower than 1500 占 폚, and the average particle diameter in Examples and Comparative Examples is as large as 7 占 퐉 or more and the density of the sintered product is as low as 6.9 g / cm3 at the maximum. Also, the strength of the sintered body is not described.

Patent Document 8 discloses a sintered body made of indium, tin and oxygen, which has a tin amount of 2 to 4 wt%, a relative density of 90% or more, and an oxide precipitate and an intermediate compound phase other than indium oxide, Or less and a specific resistance value of 1 x 10 < ^-3 > OMEGA .cm or less. However, the sintering temperature is as high as 1500 to 1700 deg. C and the specific resistance of the sintered body is also high.

Patent Document 9 discloses a sintered body which is substantially composed of indium oxide and tin oxide and has a large area of 300 mm x 300 mm or more and a thickness of 6 mm or more and which has a tin oxide content of 35 wt% or less and has a sintered density of 7.13 g / Cm < 3 >, and the maximum density difference in the planar direction of the sintered body is not more than 0.03 g / cm < 3 > , And sintering at a sintering temperature of 1450 DEG C or higher, and sintering. However, the sintering temperature is as high as 1450 DEG C or higher and the sintering method is finely defined, so that the productivity is not necessarily good.

Patent Document 10 discloses an ITO (Indium Tin Oxide) film comprising indium, tin and oxygen substantially containing a sintered body having a relative density of 99% or more and a thickness of 10 mm or more and satisfying the following formula Sputtering target. The relative density (%) of the center portion in the thickness direction of the sintered body / the density (%) of the entire sintered body ≥ 0.995 is described. However, the sintering temperatures in Examples and Comparative Examples are as high as 1600 캜, However, it is presumed that the crystal grain size is large.

In addition, all of the above documents are not produced from the viewpoint of small particle size, high density, and high strength by changing the tin oxide rich phase by low temperature sintering.

Japanese Patent No. 2750483 Japanese Laid-Open Patent Publication No. 2009-29706 Japanese Laid-Open Patent Publication No. 2009-40621 Japanese Patent Application Laid-Open No. 2000-233969 Japanese Patent No. 5206983 Japanese Laid-Open Patent Publication No. 2012-126937 Japanese Patent Application Laid-Open No. 10-147862 Japanese Patent No. 3503759 Japanese Patent No. 3988411 Japanese Patent No. 4934926

The present invention relates to an ITO sputtering target having a low-tin oxide composition capable of obtaining a film having a low resistance even at a low temperature. More specifically, the present invention relates to an ITO sputtering target having a small target particle size, high density, high strength and capable of reducing arcing and nodule . Thus, it is an object of the present invention to improve the quality of film formation and to ensure reliability.

In order to solve the above problems, the present invention provides the following invention.

1) A sintered body made of In, Sn, O, and inevitable impurities, which contains Sn at 1.8% or more and 3.7% or less (excluding 3.7%) of Sn / (In + Sn) , An average crystal grain size of the sintered body is in the range of 1.0 to 5.0 mu m, an area ratio of the pores having a major axis diameter of 0.1 to 1.0 mu m is 0.5% or less, and the sintered body has two phases of the indium oxide phase and the tin oxide rich phase, Of 0.1 to 1.0%, and at least 95% of the tin oxide rich phase exists in the grain boundary triple point.

2) The sputtering target according to the above 1), wherein Sn / (In + Sn) is contained in an atom ratio of 2.3 to 3.2%.

3) The sputtering target according to any one of 1) and 2), wherein the sintered compact has a density of 7.03 g / cm3 or more and a bulk resistivity of 0.10 to 0.15 m? · Cm.

4) The sputtering target according to any one of 1) to 3) above, wherein the maximum size on the tin oxide rich phase is 1 탆 or less.

5) The sputtering target according to any one of 1) to 4) above, wherein the bending strength is 100 MPa or more.

6) A method for producing a sputtering target comprising In, Sn, O, and inevitable impurities, wherein SnO ₂ powder and In ₂ O ₃ powder have a Sn / (In + Sn) content of 1.8% or more and 3.7% , And 3.7% are excluded), and sintering is carried out while maintaining the maximum sintering temperature at 1450 ° C or lower in an oxygen atmosphere. The method of manufacturing an ITO sputtering target according to claim 1,

7) The sputtering target according to 6) above, wherein the SnO ₂ powder and the In ₂ O ₃ powder are mixed at a ratio of 2.3 to 3.2% Sn / (In + Sn) ≪ / RTI >

(8) The method for producing a sputtering target as described in (6) or (7) above, wherein the sintering is carried out at a temperature lower than the sintering holding temperature by 100 ° C ± 20 ° C in the cooling step after sintering.

(9) A transparent conductive film comprising In, Sn, O and inevitable impurities, wherein Sn / (In + Sn) is 1.8% or more and 3.7% or less Wherein the film has a film resistivity of not more than 3.0 m? · Cm and a transmittance of not less than 80% at a wavelength of 550 nm.

10) The transparent conductive film according to the above 8), wherein Sn / (In + Sn) in an atomic ratio is 2.3 to 3.2% Sn.

11) The transparent conductive film according to any one of the above 9) or 10), wherein the crystallization temperature is 120 占 폚 or less.

(12) A method for producing a transparent conductive film by sputtering, comprising the steps of: heating a substrate in an atmosphere of a mixed gas comprising argon and oxygen at an oxygen concentration of 4% A method for manufacturing a transparent conductive film, wherein a film is formed on a substrate by using the sputtering target according to any one of claims 1 to 5.

The present invention relates to an ITO sputtering target having a low-tin oxide composition capable of obtaining a film having a low resistance even at a low temperature, which is preferable for formation of a transparent conductive film. The ITO sputtering target has a small target particle size, high density, Target can be provided. As a result, the quality of the film formation can be improved and reliability can be secured. As a result, the productivity and reliability of the target can be improved.

Fig. 1 is a graph showing the results of measurement of x2000 times of Sn of an ITO sintered body containing Sn having Sn / (In + Sn) of 3.8% in atomic ratio by FE-EPMA (JEON-8500F FE electronic probe microanalyzer, Fig.
2 is a view (A, B, C, D) illustrating that the tin oxide rich phase is present at 95% or more of the intergranular triple point.
Fig. 3 is a drawing (photograph) of a target after 35 hours of continuous sputtering, showing the nodule coating rate. Fig.
Fig. 4 is a view showing a specific example of the observation point of the sintered body (in the case of a circular sintered body, in the case of a square sintered body, cylindrical).

In the present invention, the sputtering target is a sintered body made of In, Sn, O and inevitable impurities, and Sn / (In + Sn) in the atomic ratio is 1.8% or more and 3.7% or less The average grain size of the sintered body is in the range of 1.0 to 5.0 mu m and the ratio of the area of the pores having the major axis diameter of 0.1 to 1.0 mu m is 0.5% or less, and the two phases of the indium oxide phase and the tin oxide rich phase , And the area ratio of the stannic oxide-rich phase is 0.1 to 1.0% or less, and 95% or more of the tin oxide-rich phase exists in the intergranular triple point.

A numerical limitation of the lower limit value of 1.8%, which is Sn / (In + Sn), and 1.8% or more and 3.7% or less (excluding 3.7%) of Sn in terms of the atomic ratio, indicates that a tin oxide rich phase is not present at less than 1.8% It is by reason. Further, the numerical limitation of the upper limit value of 3.7% (excluding 3.7%) is that the area ratio of the stannic oxide rich phase becomes larger than 1%. It is more effective to contain Sn having an atomic ratio of Sn / (In + Sn) of 2.3 to 3.2%.

The average crystal grain size of the sintered body should be in the range of 1.0 to 5.0 mu m. If the average crystal grain size is less than 1.0 占 퐉, the problem is that the density is not increased because the crystal grain size is too small. When the average grain size exceeds 5.0 占 퐉, the sintered body bending strength becomes smaller than 100 MPa.

When the ratio of the area of the pores having a major axis diameter of 0.1 to 1.0 占 퐉 in the sintered body is set to 0.5% or less, the presence of vacancies is not only attributed to a decrease in density but also causes arcing due to residual gas in the pores As little as possible. The pores having a major axis diameter of less than 0.1 mu m in the sintered body can be neglected because they do not affect the characteristics of the target. On the other hand, for pores exceeding 1.0 탆, they should not be present.

The texture of the sintered body becomes two phases on the indium oxide phase and the tin oxide rich phase. As a result of surface analysis in EPMA, the area ratio of the stannic oxide rich phase should be 0.1 to 1.0% or less. It is a necessary condition to realize a sintered body having a small average crystal grain size and to obtain characteristics of the sputtering target of the present invention.

The present invention requires that at least 95% of the tin oxide rich phase be present at the intergranular triple point. (The target is uniformly dispersed, and the stannic oxide-rich phase exists in its dispersed state at the intergranular triple point). In this case, the term "intergranular triple point" means that the three- Phase is present. However, in order to obtain such a state (at least 95% of the tin oxide rich phase exists in the grain boundary triple point), it is necessary to maintain the temperature at a low temperature of 100 ° C ± 20 ° C from the sintering holding temperature in the cooling step. The ITO sputtering target can further improve the conductivity by increasing the density of the sintered body to a high density of 7.03 g / cm 3 or more and setting the bulk resistivity to 0.10 to 0.15 m? · Cm. The maximum size of the above-mentioned stannic oxide-rich phase is preferably 1 占 퐉, and it is preferable that the target is a target in which coarsening on the tin oxide rich state is suppressed.

It is also preferable to increase the strength of the target by setting the bending strength of the sintered body of the ITO sputtering target to 100 MPa or more, and the present invention can realize this.

In the production of the sintered ITO sputtering target made of the indium oxide, tin oxide and inevitable impurities of the present invention, the SnO ₂ powder and the In ₂ O ₃ powder were mixed so as to have an atomic ratio of Sn / (In + Sn) % (Excluding 3.7%), and sintering is carried out while maintaining the maximum sintering temperature at 1450 ° C or lower in an oxygen atmosphere.

The indium oxide-tin oxide (ITO) sintered target of the present invention can be produced by a process of mixing, grinding, molding, and sintering each raw material powder. As the raw material powder, it is preferable to use indium oxide powder and tin oxide powder having a specific surface area of about 5 m < 2 > / g or so.

Specifically, the indium oxide powder preferably has a bulk density of 0.3 to 0.8 g / cm 3, a median diameter (D ₅₀ ) of 0.5 to 2.5 μm, a specific surface area of 3.0 to 6.0 m 2 / g, A median diameter (D ₅₀ ) of 1.0 to 2.5 μm, and a specific surface area of 3.0 to 6.0 m 2 / g are used.

Each raw material powder is weighed so as to have a desired composition ratio, and mixed and pulverized. There are various methods for the pulverizing method depending on the particle size and the pulverized material to be required, but a wet medium agitating mill such as a bead mill is suitable. This is because the slurry in which the powder is dispersed in water is forcibly agitated with a grinding medium such as zirconia or alumina, which is a material having a high hardness, to obtain a pulverized powder with high efficiency. However, at this time, since the pulverizing medium is also worn, the pulverizing powder itself is mixed as an impurity and the treatment for a long time is not preferable.

When the pulverization amount is defined as the difference in specific surface area before and after pulverization, the amount of pulverization in the wet medium agitation mill is approximately proportional to the input energy to the pulverized product. Therefore, when pulverizing is performed, it is important to manage the accumulated electric power of the wet medium agitating mill. The difference in specific surface area (? BET) before and after pulverization is 0.5 to 5.0 m 2 / g, and the median diameter (D ₅₀ ) after pulverization is 2.5 m or less.

Next, the granulation of the finely pulverized slurry is carried out. This is to obtain a homogeneous molded body by filling the powder uniformly into the mold at the time of press forming in the next step by improving the fluidity of the powder body by assembly. There are various methods of assembling, but there is a method of using a spray drying apparatus (spray dryer) as one method of obtaining granulated powder suitable for press forming. This is a method in which spherical powder of 10 to 500 mu m in size is continuously obtained by using the powder as a slurry, dispersing it as droplets in hot air, and drying it instantaneously.

Further, by adding a binder such as polyvinyl alcohol (PVA) to the slurry and adding it to the granulated powder, the strength of the formed body can be improved. For the addition amount of PVA, an aqueous solution containing 4 to 10 wt.% Of PVA is added in an amount of 50 to 250 cc / kg to the raw powder.

In addition, by adding a plasticizer suitable for the binder, the crushing strength of the granulated powder at the time of press molding can be controlled. There is also a method of improving the strength of a molded body by adding a small amount of water to the resulting granulated powder and wetting it. In drying by a spray dryer, it is important to control the inlet temperature of the hot air and the outlet temperature.

If the temperature difference between the inlet and the outlet is large, the drying amount per unit time is increased to improve the productivity. However, when the inlet temperature is excessively high, the powder and the binder to be added may be denatured by heat and desired characteristics may not be obtained. In addition, when the outlet temperature is too low, the granulated powder may not be sufficiently dried.

Next, press forming is performed. The granulated powder is charged into a mold and molded under a pressure of 400 to 1000 kgf / cm 2 for 1 to 3 minutes. When the pressure is less than 400 kgf / cm 2, a molded body with sufficient strength and density can not be obtained. At a pressure of 1000 kgf / cm 2 or more, the molded body itself is broken due to deformation Which is undesirable for production.

An electric furnace is used to sinter the formed body in an oxygen atmosphere to obtain a sintered body. The sintering temperature is 1450 ° C or less. In this case, when the sintering temperature exceeds 1450 占 폚, the structure of the sintered body becomes single-phase and the grain size becomes coarse. Therefore, the upper limit is preferably 1450 占 폚. During the temperature increase to the sintering temperature, a binder removal process or the like may be introduced as necessary.

If the holding time at the sintering temperature is shorter than 2 hours, the sintering does not proceed sufficiently and the density of the sintered body is not sufficiently increased or the sintered body is warped. Even if the holding time exceeds 100 hours, waste which requires unnecessary energy and time is generated, which is undesirable for production. It is preferably 5 to 20 hours.

95% or more of the tin oxide rich phase may be present at the intergranular triple point by keeping the atmosphere under cooling at the time of cooling down in an atmospheric or oxygen atmosphere and maintaining the temperature at a low temperature of 100 ° C ± 20 ° C from the maximum holding temperature for about 1 hour. This is because the dissolved Sn precipitates during cooling, and it is possible to maintain 95% or more of the tin oxide rich phase at the grain boundary triple point by keeping the temperature at a low temperature of 100 占 폚 占 20 占 폚. The holding time can be set to one hour or more, but a large change can not be seen. The holding time can be appropriately adjusted to a balance with the holding temperature or the like, and is not particularly limited as long as a desired structure is obtained.

The method of measuring the bulk resistivity can be measured using, for example, the type: Σ-5 +, manufactured by NPS Corporation. In the measurement, first, a metal probe is placed on a straight line on the surface of the sample, a constant current is flowed between the two probes on the outer side, and the potential difference generated between the two probes on the inner side is measured to obtain the resistance. The volume resistivity (bulk resistivity) can be calculated by multiplying the obtained resistance by the sample thickness and the correction factor RCF (Resistance Correction Factor).

As described above, the sintered body sintered under such conditions can improve the conductivity by setting the density of the sintered body to a high density of 7.03 g / cm < 3 > or more and setting the bulk resistivity to 0.10 to 0.15 m? In addition, the maximum size on the above-mentioned tin oxide rich phase can be set to 1 占 퐉, thereby making it possible to obtain a target in which coarsening on the tin oxide rich state is suppressed.

Further, the strength of the target can be increased by setting the bending strength of the sintered body of the ITO sputtering target to 100 MPa or more.

The surface of the sintered body thus obtained was ground, and the sides were cut into a size of 127 mm x 508 mm with a diamond cutter.

Next, the backing plate of the oxygen freezing agent is placed on a hot plate set at 200 DEG C, and indium is applied as a brazing material so that its thickness becomes about 0.2 mm. The ITO sintered body was bonded to the backing plate, and left to cool to room temperature.

This target was attached to a magnetron sputtering apparatus (BSC-7011) manufactured by Shin-Kone Manufacturing Co. The sputtering gas was argon (Ar) and oxygen (O ₂ ), and the input power was 2.3 W / The total flow rate is 300 sccm, and the oxygen concentration is 0 to 4%.

Particularly, in the production of the transparent conductive film of the present invention, in the atmosphere of a mixed gas of argon and oxygen in which the oxygen concentration is 4% or less, the substrate is kept at no heating or at 150 ° C or lower and the ITO sputtering target of the present invention It is preferable to form a film on a substrate. The substrate may be a glass substrate, or a film substrate such as PET.

The transparent conductive film thus produced is a transparent conductive film made of In, Sn, O, and inevitable impurities, and Sn / (In + Sn) in the atomic ratio is 1.8% or more and 3.7% or less ), And a transparent conductive film having a film characteristic of a film having a resistivity of not more than 3.0 m? · Cm and a transmittance of not less than 80% at a wavelength of 550 nm can be obtained.

Further, a transparent conductive film containing Sn, which has an atomic ratio of Sn / (In + Sn) of 2.3 to 3.2%, and made of In, Sn, O, and inevitable impurities may be used. The transparent conductive film thus produced can have a crystallization temperature of 120 ° C or lower.

Next, the terms (definitions, test methods, etc.) used in the present specification will be described. First, the sintered body is divided into quadrants at the observation point of the target, and the center portion of the sintered body to be divided into quarters is defined as the observation point at 2 o'clock, a total of 8 o'clock. A concrete example of the observation point is indicated by & cirf & 4 shows the case of the annular sintered body, the right side view of Fig. 4 shows the case of the square sintered body, and the left side view of Fig. 4 shows the cylindrical case.

(Method of measuring average crystal grain size of sintered body)

The code method was used as a method of measuring the average crystal grain size. In the code method, a straight line is drawn from the grain boundary to grain boundaries in an arbitrary direction on an x2,000 times SEM image, and the average of the lengths of the lines crossing one grain is taken as an average grain size. On an SEM image (photograph), an arbitrary straight line (from the grain boundary to the grain boundary) is drawn, and the number of intersections with the grain boundary is counted, and the following formula 1 is calculated.

(Equation 1) Average crystal grain diameter = length of straight line / number of intersections

More specifically, five parallel lines of arbitrary length are scanned with respect to one field of view in an 8-field SEM image, and the average crystal grain size is calculated from the average of the total length of the lines and the total number of intersections of the grain boundaries.

The sample was subjected to mirror-surface polishing, followed by aqua regia etching. SEM images were taken with FE-EPMA (JEON-8500F type FE electronic probe microanalyzer, manufactured by Nihon Electronics Co., Ltd.).

(Public area ratio)

The wells were observed using x2,000 magnification SEM images. The pores were roughly circular (including the origin), elliptical, and circular, measuring the largest diameter, major axis diameter (including the diameter). The public area ratio was calculated from the histogram using a SEM image of x2,000 times the 8 field of view and after the grayscale binarization processing with Adobe Photoshop Elements 7.0 (the average area ratio of 8 fields of view) from the histogram . The sample was subjected to mirror-surface polishing, followed by aqua regia etching. SEM images were taken with FE-EPMA (JEON-8500F type FE electronic probe microanalyzer, manufactured by Nihon Electronics Co., Ltd.).

(Relative to the tin oxide rich phase)

Fig. 1 is a graph showing the results of measurement of x2000 times of FE-EPMA (JEON-8500F type FE electronic probe micro-analyzer, manufactured by Nihon Electronics Co., Ltd.) of an ITO sintered body containing Sn at an atomic ratio of Sn / (In + Sn) Of the surface of the Sn. The stannic oxide rich phase refers to an image (a white portion in the image) having a higher Sn intensity than the other phases.

The area ratio of the stannic oxide rich phase was determined by taking a Sn plane analysis image of 50 占 퐉 占 50 占 퐉 at 8 o'clock and photographing the area ratio of the area of the stannic oxide rich phase from the histogram after the grayscale and binarization processing with Adobe Photoshop Elements 7.0 Average area ratio).

The left side of Fig. 1 is a drawing (image) showing the analysis result of the Sn surface of the ITO sintered body containing Sn at an atomic ratio of Sn / (In + Sn) of 3.8%, and the right side shows a SEM image (Image).

The maximum size on the tin oxide rich phase indicates the largest long axis diameter in the image 8 visual field.

(Relative to the indium oxide phase)

An image other than the tin oxide rich phase in the Sn plane analysis of FIG. 1 is defined as an indium oxide phase.

(Explanation regarding the presence of 95% or more of the tin oxide rich phase in the grain boundary triple point)

The intergranular triple point: A in FIG. 2 is an SEM image of an ITO sintered body containing 2.8% Sn / (In + Sn) in atomic ratio. When a line is drawn along the grain boundary of FIG. 2 A, . The intergranular triple point refers to the point of intersection of the grain boundaries of the three particles, as shown in Fig. 2B. A portion " B " in Fig. 2 indicates a portion that is not an intergranular triple point.

Fig. 2C is a plane analysis result of Sn of the same visual field as A in Fig. 2, and a portion surrounded by a dotted line is a tin oxide rich phase. 2C was observed to see whether or not the tin oxide rich phase was located at the grain boundary triple point and the ratio of the number of tin oxide rich phase to the number of tin oxide rich phase located at the grain boundary triple point Is 95% or more. 2D is an SEM image obtained by polymerizing A in Fig. 2 and C in Fig.

(Test method for bending strength of sintered body)

The bending strength of fine ceramics (JIS R 1601) was tested in accordance with the three-point bending test. The number of specimens is 20, and the numerical values are average values. The device used was Imada's tensile compression testing machine (SV-201NA-50SL type).

(Arcing detection sensitivity)

The number of arcing (micro arc) occurrences (times) was measured with a Landmark Technology manufactured micro arc monitor (MAM Genesis). Arcing criteria were as follows: Arching with a detection voltage of 100 V or higher and emission energy (sputtering voltage x sputtering current x generation time when arc discharge was occurring) of 20 mJ or less was counted.

(Nodule coverage rate)

Fig. 3 is a photograph of a target after 35 hours of continuous sputtering. A white dotted line frame was photographed with a digital camera, and after the grayscale and binarization processing (see Fig. 3) with Adobe Photoshop Elements 7.0, And the average of the three points was defined as the nodule coverage.

Example

Hereinafter, the present invention will be described on the basis of examples and comparative examples, but these examples and comparative examples are for the sake of easy understanding, and the present invention is not limited by these examples. That is, modifications and other embodiments based on the technical idea of the present invention are naturally included in the present invention.

(Example 1)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 5 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.070 g / cm 3, a bending strength of 115 MPa, a bulk resistivity of 0.110 m? 占, m, an average crystal grain size of 3.43 占 퐉, an area ratio of 0.45% on a tin oxide rich phase, The public area rate was 0.08%.

The sputtering was carried out continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 1%.

The results are shown in Table 1.

(Example 2)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, the temperature was maintained at 1330 캜 for one hour during cooling down. The sintered body thus obtained had a sintered body density of 7.100 g / cm3, a bending strength of 120 MPa, a bulk resistivity of 0.116 m? 占, m, an average crystal grain size of 3.54 占 퐉, an area ratio of 0.39% on a tin oxide rich phase, The public area rate was 0.07%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 0.8%.

In Example 2, the same DC power density and gas pressure were applied to the glass substrate (Eagle XG) at a gas flow rate of 300 sccm with argon and oxygen at 0, 1, 2, and 4% Thus, a 40 nm ITO film was formed.

This film was heated to 50 to 200 ° C in an atmospheric environment for 60 minutes using an inert oven furnace (model number INL-45-S), and the film before and after heating was subjected to XRD (apparatus model number: Rigaku Co., X-ray diffractometer SmartLab). The crystallization temperature was set to a temperature at which a peak of (222) plane of In ₂ O ₃ was confirmed by XRD measurement.

When the oxygen concentration was 0%, the film resistivity was 2.70 m? 占. M, the transmittance at 500 nm wavelength was 80.5%, and the crystallization temperature was 100 占 폚.

When the oxygen concentration was 1%, the film resistivity was 1.01 m? 占. M, the transmittance at a wavelength of 500 nm was 84.0%, and the crystallization temperature was 100 占 폚.

When the oxygen concentration was 2%, the film resistivity was 0.59 m? 占. M, the transmittance at a wavelength of 500 nm was 88.1%, and the crystallization temperature was 100 占 폚.

When the oxygen concentration was 4%, the film resistivity was 0.81 m? 占. M, the transmittance at a wavelength of 500 nm was 87.4%, and the crystallization temperature was 100 占 폚.

The results are shown in Table 2. All, good results were obtained.

(Example 3)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 15 hours. Thereafter, it was held at 1370 캜 for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.105 g / cm3, a bending strength of 121 MPa, a bulk resistivity of 0.124 m? 占, m, an average crystal grain size of 3.66 占 퐉, an area ratio of 0.35% on a tin oxide rich phase, The public area rate was 0.05%.

The sputtering was continuously performed for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar), and a gas flow rate of 300 sccm. As a result, Times / 24 hr, and the nodule coverage rate was 0.3%.

(Example 4)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1430 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, the temperature was maintained at 1330 캜 for one hour during cooling down. The sintered body thus obtained had a sintered body density of 7.082 g / cm3, a bending strength of 116 Mpa, a bulk resistivity of 0.118 m? 占, m, an average crystal grain size of 3.26 占 퐉, an area ratio of 0.98% on a tin oxide rich phase, The public area rate was 0.10%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 0.7%.

(Example 5)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1400 캜, and the retention time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1300 占 폚 for one hour at the time of cold cooling. The sintered body thus obtained had a sintered body density of 7.058 g / cm 3, a bending strength of 113 MPa, a bulk resistivity of 0.121 m? 占, m, an average crystal grain size of 3.20 占 퐉, an area ratio of 0.83% on a tin oxide rich phase, The public area rate was 0.15%.

The sputtering was carried out continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 1.2%.

(Example 6)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1350 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1250 占 폚 for one hour during cold cooling. The sintered body thus obtained had a sintered body density of 7.036 g / cm 3, a bending strength of 110 MPa, a bulk resistivity of 0.129 m? 占, m, an average crystal grain size of 3.01 占 퐉, an area ratio of 0.95% on the tin oxide rich phase, The public area rate was 0.23%.

As a result of sputtering for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours, Times / 24 hr and the nodule coverage rate was 1.5%.

(Example 7)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.074 g / cm 3, a bending strength of 111 MPa, a bulk resistivity of 0.131 m? 占, m, an average crystal grain size of 3.96 占 퐉, an area ratio of 0.21% on a tin oxide rich phase, The public area rate was 0.08%.

The sputtering was carried out continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 0.9%.

In Example 7, the same DC power density and gas pressure were applied to the glass substrate (Eagle XG) at a gas flow rate of 300 sccm with argon and oxygen at 0, 1, 2, and 4% Thus, a 40 nm ITO film was formed.

This film was heated to 50 to 200 ° C in an atmospheric environment for 60 minutes using an inert oven furnace (model number INL-45-S), and the film before and after heating was subjected to XRD (apparatus model number: Rigaku Co., X-ray diffractometer SmartLab). The crystallization temperature was set to a temperature at which a peak of (222) plane of In ₂ O ₃ was confirmed by XRD measurement.

When the oxygen concentration was 0%, the film resistivity was 2.93 m? 占. M, the transmittance at a wavelength of 500 nm was 81.1%, and the crystallization temperature was 80 占 폚.

When the oxygen concentration was 1%, the film resistivity was 1.33 m? 占. M, the transmittance at a wavelength of 500 nm was 83.2%, and the crystallization temperature was 80 占 폚.

When the oxygen concentration was 2%, the film resistivity was 0.65 m? 占. M, the transmittance at a wavelength of 500 nm was 88.7%, and the crystallization temperature was 80 占 폚.

When the oxygen concentration was 4%, the film resistivity was 0.96 m? 占. M, the transmittance at a wavelength of 500 nm was 86.9%, and the crystallization temperature was 80 占 폚.

The results are also shown in Table 2. All, good results were obtained.

(Example 8)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1400 캜, and the retention time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1300 占 폚 for one hour at the time of cold cooling. The sintered body thus obtained had a sintered body density of 7.045 g / cm3, a bending strength of 107 MPa, a bulk resistivity of 0.125 m? 占, m, an average crystal grain size of 3.46 占 퐉, an area ratio of 0.26% on a tin oxide rich phase, The public area rate was 0.11%.

As a result of sputtering for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours, the number of arcing occurrences was 33 Times / 24 hr, and the nodule coverage rate was 1.2%.

(Example 9)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.1% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.079 g / cm 3, a bending strength of 113 MPa, a bulk resistivity of 0.125 m? 占, m, an average crystal grain size of 3.55 占 퐉, an area ratio of 0.18% on a tin oxide rich phase, The public area rate was 0.12%.

The sputtering was carried out continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 1.3%.

(Example 10)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.1% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1400 캜, and the retention time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1300 占 폚 for one hour at the time of cold cooling. The sintered body thus obtained had a sintered body density of 7.050 g / cm 3, a bending strength of 110 MPa, a bulk resistivity of 0.122 m? 占, m, an average crystal grain size of 2.75 占 퐉, an area ratio of 0.22% on a tin oxide rich phase, The public area rate was 0.13%.

The sputtering was carried out continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 1.6%.

(Example 11)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.6% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.088 g / cm3, a bending strength of 119 Mpa, a bulk resistivity of 0.123 m? 占, m, an average crystal grain size of 2.97 占 퐉, an area ratio of 0.33% on a tin oxide rich phase, The public area rate was 0.10%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 1%.

(Example 12)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.6% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1400 캜, and the retention time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1300 占 폚 for one hour at the time of cold cooling. The sintered body thus obtained had a sintered body density of 7.071 g / cm3, a bending strength of 115 MPa, a bulk resistivity of 0.119 m? 占, m, an average crystal grain size of 2.83 占 퐉, an area ratio of 0.38% on a tin oxide rich phase, The public area rate was 0.10%.

The sputtering was carried out continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 1.1%.

(Example 13)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 3.0% in atomic ratio were sintered in an oxygen atmosphere as a raw material for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.103 g / cm 3, a bending strength of 126 MPa, a bulk resistivity of 0.117 m? 占, m, an average crystal grain size of 3.67 占 퐉, an area ratio of 0.41% on a tin oxide rich phase, The public area rate was 0.08%.

The sputtering was continuously performed for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar), and a gas flow rate of 300 sccm. As a result, Times / 24 hr, and the nodule coverage rate was 0.9%.

(Example 14)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 3.0% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1400 캜, and the retention time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1300 占 폚 for one hour at the time of cold cooling. The sintered body thus obtained had a sintered body density of 7.091 g / cm3, a bending strength of 121 MPa, a bulk resistivity of 0.115 m? 占, m, an average crystal grain size of 3.49 占 퐉, an area ratio of 0.40% on a tin oxide rich phase, The public area rate was 0.09%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 0.9%.

(Example 15)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 3.2% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.109 g / cm 3, a bending strength of 127 MPa, a bulk resistivity of 0.110 m? 占, m, an average crystal grain size of 3.82 占 퐉, an area ratio of 0.55% on a tin oxide rich phase, The public area rate was 0.07%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 0.7%.

In Example 15, the same DC power density and gas pressure were used as the sputter gas, and argon was added to the glass substrate (Eagle XG) at a gas flow rate of 300 sccm with no oxygen at 0, 1, 2, and 4% Thus, a 40 nm ITO film was formed.

This film was heated to 50 to 200 ° C in an atmospheric environment for 60 minutes using an inert oven furnace (model number INL-45-S), and the film before and after heating was subjected to XRD (apparatus model number: Rigaku Co., X-ray diffractometer SmartLab). The crystallization temperature was set to a temperature at which a peak of (222) plane of In ₂ O ₃ was confirmed by XRD measurement.

When the oxygen concentration was 0%, the film resistivity was 2.65 m? 占. M, the transmittance at a wavelength of 500 nm was 80.1%, and the crystallization temperature was 110 占 폚.

When the oxygen concentration was 1%, the film resistivity was 0.97 m? 占. M, the transmittance at a wavelength of 500 nm was 83.6%, and the crystallization temperature was 110 占 폚.

When the oxygen concentration was 2%, the film resistivity was 0.60 m? 占. M, the transmittance at 500 nm wavelength was 89.2%, and the crystallization temperature was 110 占 폚.

When the oxygen concentration was 4%, the film resistivity was 0.84 m? 占. M, the transmittance at a wavelength of 500 nm was 87.6%, and the crystallization temperature was 110 占 폚.

The results are also shown in Table 2. All, good results were obtained.

(Example 16)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 3.2% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1400 캜, and the retention time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1300 占 폚 for one hour at the time of cold cooling. The sintered body thus obtained had a sintered compact density of 7.100 g / cm3, a bending strength of 123 MPa, a bulk resistivity of 0.104 m? 占, m, an average crystal grain size of 3.77 占 퐉, an area ratio of 0.62% on a tin oxide rich phase, The public area rate was 0.06%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 0.6%.

(Example 17)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 3.5% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered compact density of 7.112 g / cm3, a bending strength of 130 MPa, a bulk resistivity of 0.111 m? 占, m, an average crystal grain size of 4.02 占 퐉, an area ratio of 0.62% on a tin oxide rich phase, The public area rate was 0.06%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Times / 24 hr, and the nodule coverage rate was 0.6%.

(Example 18)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 3.5% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1400 캜, and the retention time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1300 占 폚 for one hour at the time of cold cooling. The obtained sintered body had a sintered body density of 7.102 g / cm3, a bending strength of 128 MPa, a bulk resistivity of 0.106 m? 占, m, an average crystal grain size of 3.89 占 퐉, an area ratio of 0.70% on a tin oxide rich phase, The public area rate was 0.05%.

The sputtering was continuously performed for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar), and a gas flow rate of 300 sccm. As a result, Times / 24 hr and the nodule coverage rate was 0.5%.

(Comparative Example 1)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1550 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1450 ° C for 1 hour during cooling down. The sintered body thus obtained had a sintered body density of 7.112 g / cm3, a bending strength of 122 MPa, a bulk resistivity of 0.135 m? 占, m, an average crystal grain size of 7.64 占 퐉, an area ratio of 0.001% on a tin oxide rich phase, The public area rate was 0.52%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar), and a gas flow rate of 300 sccm for 35 hours. As a result, / 24 hr, and the Nodule coverage rate was 2.5%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 2)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was set to 1500 ° C, and the holding time at the maximum sintering temperature was set to 10 hours. Thereafter, the temperature was maintained at 1400 캜 for one hour during cooling down. The sintered body thus obtained had a sintered body density of 7.106 g / cm3, a bending strength of 120 MPa, a bulk resistivity of 0.124 m? 占, m, an average crystal grain size of 5.98 占 퐉, an area ratio of 0.02% on a tin oxide rich phase, The public area rate was 0.68%.

The sputtering was continuously performed for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar), and a gas flow rate of 300 sccm. As a result, Hr / 24 hr, and the nodule coverage rate was 3.1%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 3)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 1 hour. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a density of sintered body of 6.989 g / cm3, a bending strength of 103 MPa, a bulk resistivity of 0.121 m? 占, m, an average crystal grain size of 3.25 占 퐉, an area ratio of 0.58% on a tin oxide rich phase, The public area rate was 0.20%.

The sputtering was carried out continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Hr / 24 hr, and the nodule coverage rate was 4.8%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 4)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1550 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1450 ° C for 1 hour during cooling down. The sintered body thus obtained had a sintered body density of 7.098 g / cm3, a bending strength of 115 MPa, a bulk resistivity of 0.125 m? 占, m, an average crystal grain size of 6.21 占 퐉, an area ratio of 0.001% on a tin oxide rich phase, The public area rate was 0.55%.

The sputtering was continuously performed for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar), and a gas flow rate of 300 sccm. As a result, / 24 hr, and the nodule coverage rate was 2.6%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 5)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was set to 1500 ° C, and the holding time at the maximum sintering temperature was set to 10 hours. Thereafter, the temperature was maintained at 1400 캜 for one hour during cooling down. The sintered body thus obtained had a sintered body density of 7.066 g / cm 3, a bending strength of 111 MPa, a bulk resistivity of 0.120 m? 占, m, an average crystal grain size of 5.12 占 퐉, an area ratio of 0.001% on a tin oxide rich phase, The public area rate was 0.63%.

The sputtering was carried out continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Hr / 24 hr, and the nodule coverage rate was 2.9%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 6)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.6% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.048 g / cm3, a bending strength of 103 MPa, a bulk resistivity of 0.133 m? 占, m, an average crystal grain size of 4.05 占 퐉, an area ratio of 0.001% on a tin oxide rich phase, The public area rate was 0.62%.

As a result of sputtering for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa and a sputter gas of argon (Ar) at a gas flow rate of 300 sccm, the number of arcings was 128 Hr / 24 hr, and the nodule coverage rate was 2.9%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 7)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.6% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1400 캜, and the retention time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1300 占 폚 for one hour at the time of cold cooling. The sintered body thus obtained had a sintered body density of 7.024 g / cm3, a bending strength of 98 Mpa, a bulk resistivity of 0.138 m? 占, m, an average crystal grain size of 3.83 占 퐉, an area ratio of 0.02% on a tin oxide rich phase, The public area rate was 0.66%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, / 24 hr, and the nodule coverage rate was 3.3%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 8)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.4% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.030 g / cm3, a bending strength of 99 Mpa, a bulk resistivity of 0.139 m? 占, m, an average crystal grain size of 4.68 占 퐉, an area ratio of 0.001% on a tin oxide rich phase, The public area rate was 0.78%.

The sputtering was continuously performed for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar), and a gas flow rate of 300 sccm. As a result, Hr / 24 hr, and the nodule coverage rate was 3.2%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

In Comparative Example 8, the same DC power density and gas pressure were applied to the glass substrate (Eagle XG) at a gas flow rate of 300 sccm with argon and oxygen at 0, 1, 2, and 4% Thus, a 40 nm ITO film was formed.

This film was heated to 50 to 200 DEG C in an atmospheric air for 60 minutes using an inert gas oven furnace (model number INL-45-S), and the film before and after heating was subjected to XRD (apparatus model number: Rigaku Co., The presence of crystallization was confirmed by a multi-purpose X-ray diffraction device SmartLab). The crystallization temperature was set to a temperature at which a peak of (222) plane of In ₂ O ₃ was confirmed by XRD measurement.

When the oxygen concentration was 0%, the film resistivity was 6.21 m? 占. M, the transmittance at a wavelength of 500 nm was 72.9%, and the crystallization temperature was 50 占 폚.

When the oxygen concentration was 1%, the film resistivity was 4.60 m? 占. M, the transmittance at a wavelength of 500 nm was 76.3%, and the crystallization temperature was 50 占 폚.

When the oxygen concentration was 2%, the film resistivity was 3.01 m? 占. M, the transmittance at a wavelength of 500 nm was 78.7%, and the crystallization temperature was 50 占 폚.

When the oxygen concentration was 4%, the film resistivity was 4.38 m? 占. M, the transmittance at a wavelength of 500 nm was 75.4%, and the crystallization temperature was 50 占 폚.

The results are also shown in Table 2. All of them did not satisfy the conditions of the present invention and became defective.

(Comparative Example 9)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.4% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1400 캜, and the retention time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1300 占 폚 for one hour at the time of cold cooling. The sintered body thus obtained had a sintered body density of 7.015 g / cm3, a bending strength of 90 MPa, a bulk resistivity of 0.145 m? 占, m, an average crystal grain size of 4.07 占 퐉, an area ratio of 0.001% on a tin oxide rich phase, The public area rate was 0.85%.

As a result of sputtering continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, and a sputter gas of argon (Ar) and a gas flow rate of 300 sccm, the number of arcing occurred was 162 Hr / 24 hr, and the nodule coverage rate was 3.5%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 10)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.2% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.009 g / cm3, a bending strength of 88 MPa, a bulk resistivity of 0.148 m? 占, m, an average crystal grain size of 5.03 占 퐉, an area ratio of 0.001% on a tin oxide rich phase, The public area rate was 0.88%.

The sputtering was continuously performed for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm, and the number of arcing occurred was 173 / 24 hr, and the nodule coverage rate was 3.8%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 11)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 1.2% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1400 캜, and the retention time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1300 占 폚 for one hour at the time of cold cooling. The sintered body thus obtained had a density of sintered body of 6.994 g / cm 3, a bending strength of 80 MPa, a bulk resistivity of 0.156 m? 占, m, an average crystal grain size of 4.54 占 퐉, an area ratio of 0.001% on a tin oxide rich phase, The public area rate was 1.02%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, / 24 hr, and the nodule coverage rate was 1.3%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 12)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 3.7% in terms of atomic ratio were sintered in an oxygen atmosphere using as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1350 ° C for one hour during cooling down by cooling. The sintered body thus obtained had a sintered body density of 7.112 g / cm3, a bending strength of 120 MPa, a bulk resistivity of 0.120 m? 占, m, an average crystal grain size of 4.32 占 퐉, an area ratio of 2.3% on a tin oxide rich phase, The public area rate was 0.22%.

The sputtering was carried out continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, / 24 hr, and the nodule coverage rate was 1.3%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

In Comparative Example 12, the same DC power density and gas pressure were applied to the glass substrate (Eagle XG) at a gas flow rate of 300 sccm with argon and oxygen at 0, 1, 2, and 4% Thus, a 40 nm ITO film was formed.

This film was heated to 50 to 200 DEG C in an atmospheric air for 60 minutes using an inert gas oven furnace (model number INL-45-S), and the film before and after heating was subjected to XRD (apparatus model number: Rigaku Co., The presence of crystallization was confirmed by a multi-purpose X-ray diffraction device SmartLab). The crystallization temperature was set to a temperature at which a peak of (222) plane of In ₂ O ₃ was confirmed by XRD measurement.

When the oxygen concentration was 0%, the film resistivity was 2.74 m? 占. M, the transmittance at a wavelength of 500 nm was 77.1%, and the crystallization temperature was 130 占 폚.

When the oxygen concentration was 1%, the film resistivity was 0.99 m? 占. M, the transmittance at a wavelength of 500 nm was 84.6%, and the crystallization temperature was 130 占 폚.

When the oxygen concentration was 2%, the film resistivity was 0.61 m? 占. M, the transmittance at a wavelength of 500 nm was 86.8%, and the crystallization temperature was 130 占 폚.

When the oxygen concentration was 4%, the film resistivity was 0.87 m? 占. M, the transmittance at a wavelength of 500 nm was 85.1%, and the crystallization temperature was 130 占 폚.

The results are also shown in Table 2. All of them did not satisfy the conditions of the present invention and became defective.

(Comparative Example 13)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, cooling was carried out without keeping at a specific temperature. The sintered body thus obtained had a sintered body density of 7.093 g / cm 3, a bending strength of 110 MPa, a bulk resistivity of 0.110 m? 占, m, an average crystal grain size of 3.55 占 퐉, an area ratio on the tin oxide rich phase of 0.10%, a stannous oxide- The public area rate was 0.07%.

As a result of sputtering for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours, the number of arcing occurred was 156 Hr / 24 hr, and the nodule coverage rate was 2.0%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 14)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, it was held at 1250 占 폚 for one hour during cold cooling. The sintered body thus obtained had a sintered compact density of 7.095 g / cm 3, a bending strength of 115 MPa, a bulk resistivity of 0.123 m? 占, m, an average crystal grain size of 3.58 占 퐉, an area ratio of 0.08% on a tin oxide rich phase, The public area rate was 0.06%.

The sputtering was performed continuously for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar) and a gas flow rate of 300 sccm for 35 hours. As a result, Hr / 24 hr, and the nodule coverage rate was 2.2%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

(Comparative Example 15)

SnO ₂ powder and In ₂ O ₃ powder whose ratios were adjusted so that Sn / (In + Sn) was 2.8% in terms of atomic ratio were sintered in an oxygen atmosphere as raw materials for sintering. The maximum sintering temperature was 1450 ° C and the holding time at the maximum sintering temperature was 10 hours. Thereafter, the temperature was maintained at 1400 캜 for one hour during cooling down. The sintered body thus obtained had a sintered body density of 7.100 g / cm 3, a bending strength of 120 MPa, a bulk resistivity of 0.136 m? 占, m, an average crystal grain size of 3.65 占 퐉, an area ratio of 0.05% on a tin oxide rich phase, The public area rate was 0.07%.

The sputtering was continuously performed for 35 hours at a DC power density of 2.3 W / cm 2, a gas pressure of 0.6 Pa, a sputter gas of argon (Ar), and a gas flow rate of 300 sccm. As a result, / 24 hr, and the nodule coverage rate was 2.6%, which was unsatisfactory because it did not satisfy the conditions of the present invention.

The film resistivity, the transmittance at a wavelength of 500 nm, and the crystallization temperature in the case of changing the oxygen concentration in the case of sputtering in the above-mentioned Examples and Comparative Examples were measured in the same manner as in Example 2, Example 7, Example 15, 8 and the comparative example 12, and the other examples and comparative examples are omitted, but this is to avoid complications, and it is added that the same results are obtained.

Industrial availability

The present invention relates to an ITO sputtering target having a low-tin oxide composition capable of obtaining a film having a low resistance even at a low temperature, which is preferable for formation of a transparent conductive film. The ITO sputtering target has a small particle size, high density, high strength, An ITO sputtering target can be provided.

Further, it is possible to reduce the change in the film characteristics accompanying the progress of the sputtering and to improve the quality of the film formation. As a result, the productivity and reliability of the ITO target can be improved. INDUSTRIAL APPLICABILITY The ITO sputtering target of the present invention is particularly useful for forming an ITO film, and is most suitable for applications such as a touch panel, a flat panel display, an organic EL, and a solar cell.

Claims (12)

A sintered body made of In, Sn, O and inevitable impurities and containing Sn at an atomic ratio of Sn / (In + Sn) of 1.8% or more and 3.7% or less (excluding 3.7% The average crystal grain size is in the range of 1.0 to 5.0 mu m, the pore size of the major axis diameter of 0.1 to 1.0 mu m is 0.5% or less, the two phases are the indium oxide phase and the tin oxide rich phase, 0.1 to 1.0%, and at least 95% of the tin oxide rich phase is present at the grain boundary triple point. The method according to claim 1,
Wherein Sn contains Sn in an atomic ratio of 2.3 to 3.2% Sn / (In + Sn). 3. The method according to claim 1 or 2,
Wherein the sintered body has a density of 7.03 g / cm3 or more and a bulk resistivity of 0.10 to 0.15 m? 占 · m. 4. The method according to any one of claims 1 to 3,
Wherein the maximum size on the tin oxide rich phase is 1 占 퐉 or less. 5. The method according to any one of claims 1 to 4,
And a bending strength of 100 MPa or more. A method for producing a sputtering target comprising In, Sn, O, and inevitable impurities, characterized in that SnO ₂ powder and In ₂ O ₃ powder have a Sn / (In + Sn) content of 1.8% or more and 3.7% %), And the sintering is carried out while maintaining the maximum sintering temperature at 1450 ° C or lower in an oxygen atmosphere. The method of manufacturing an ITO sputtering target according to claim 1, The method according to claim 6,
SnO ₂ powder and In ₂ O ₃ powder are mixed at a ratio of Sn / (In + Sn) so that the ratio of Sn / (In + Sn) is 2.3 to 3.2%, and sintered. 8. The method according to claim 6 or 7,
Wherein the sintering temperature is maintained at a temperature lower by 100 占 폚 占 0 占 폚 than the sintering holding temperature in the cooling step after sintering. A transparent conductive film made of In, Sn, O and inevitable impurities and containing Sn at 1.8% or more and 3.7% or less (but excluding 3.7%) of Sn / (In + Sn) , The film having a resistivity of not more than 3.0 m? · Cm in a non-heating film, and a film characteristic of not less than 80% in transmissivity at a wavelength of 550 nm. 10. The method of claim 9,
Wherein Sn contains Sn in an atomic ratio of Sn / (In + Sn) of 2.3 to 3.2%. 11. The method according to claim 9 or 10,
Wherein the crystallization temperature is 120 占 폚 or lower. A method for producing a transparent conductive film by sputtering, comprising: a step of holding the substrate in a mixed gas atmosphere of argon and oxygen at an oxygen concentration of 4% or less without heating or at 150 ° C or less, A method for manufacturing a transparent conductive film, wherein a film is formed on a substrate using the sputtering target according to any one of claims 1 to 5.

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