TW201522689A - Sputtering target and method for producing same - Google Patents

Abstract

A sputtering target which contains a hexagonal layered compound that is mainly composed of indium oxide and zinc oxide and is represented by formula In2O3(ZnO)m (wherein m is an integer of 2-7), and which also contains elemental Sn and elemental Zr. The ratio of elemental Sn relative to all metal elements in this sputtering target is more than 2,000 ppm but 20,000 ppm or less.

Description

Sputtering target and manufacturing method thereof

The present invention relates to a sputtering target suitable for producing an oxide film, a method for producing the same, an oxide film formed by the target, and a product using the same.

A transparent conductive film containing a metal composite oxide having both conductivity and light transmittance has been used for automobile windows or buildings in addition to solar cells, liquid crystal display elements, electrodes in various other elements, and the like. A wide range of applications such as a heat reflecting film, an antistatic film, and a transparent heat generating body for antifogging in a refrigerating display case. It is known that a transparent conductive film which is particularly low in electrical resistance and excellent in electrical conductivity can be preferably used for a solar cell, a display device such as a liquid crystal, an organic electroluminescence or an inorganic electroluminescence, or an electronic device such as a touch panel.

The most popular one among such transparent conductive films is a transparent conductive film containing indium oxide-tin oxide (indium tin oxide) called ITO (Indium Tin Oxides).

Further, indium oxide-zinc oxide (indium zinc oxide), a ruthenium added to tin oxide, or aluminum is added to zinc oxide. These are different in terms of ease of manufacture, price, characteristics, and the like, and are appropriately used depending on the use.

The indium zinc oxide film has a feature that the etching rate is higher than that of the ITO film. However, since the indium zinc oxide target has a bulk resistance higher than that of the ITO target, there is a case where the discharge in the sputtering is unstable particularly in the DC (Direct Current) magnetron sputtering process.

It is known that in the indium oxide-based sintered body, the body resistance is lowered by adding about 5% of tin oxide, and the same effect is obtained in the indium zinc oxide sintered body. However, such a large amount of addition of tin oxide loses the characteristics of the indium zinc oxide transparent conductive film, so it is difficult Speaking must be consistent with the purpose.

Therefore, in Patent Document 1, it is proposed to add an oxide of a third element having a positive tetravalent or higher valence to a small addition amount of about 0.01 to 1 atom% in the indium zinc oxide, thereby lowering the body resistance value of the target. The discharge of the target at the time of sputtering is stabilized, and at the same time, the etching speed of the oxalic acid etchant which can be industrially applied is achieved.

However, the target added with the third element addition amount described in the example of Patent Document 1 produces color unevenness on the target surface during the sintering process at the time of production, and must be polished until the color unevenness disappears. Therefore, the tact time of the manufacturing becomes longer, and the yield is also greatly lowered. On the other hand, in the target in which the amount of the third element added was sequentially increased, the generation of color unevenness was suppressed, but a large amount of fine particles were observed on the film formation substrate at the time of sputtering film formation.

In Example 1 and Example 2 of Patent Document 2, it is disclosed that the addition of a target of cerium oxide as a rare earth oxide in the production of an indium oxide-zinc oxide target can effectively prevent color unevenness, and is disclosed in Example 3. The target of cerium oxide can effectively prevent color unevenness. However, in the target in which the rare earth oxide is added, although the color unevenness during the sintering process can be prevented, the resistance value of the transparent conductive film formed is increased, and the etching performance (speed and residue) of the oxalic acid etchant is also Poor. Moreover, the number of particles at the time of sputtering film formation also increases.

Prior technical literature Patent literature

Patent Document 1: International Publication No. WO2003/008661

Patent Document 2: Japanese Patent Laid-Open No. 2001-11613

An object of the present invention is to provide a sputtering target which can reduce the amount of polishing during the production of a sputtering target by suppressing the occurrence of color unevenness during sintering, thereby improving the manufacturing station time and yield, and also suppressing film formation. The generation of particles.

According to the present invention, there are provided the following sputtering target, a method for producing the same, an oxide film formed by the target, and a product using the same.

A sputtering target comprising a hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m (wherein, m is an integer of 2 to 7), wherein indium oxide and zinc oxide are main components, and The Sn element and the Zr element are contained, and the ratio of the Sn element to all the metal elements is more than 2000 ppm and is 20,000 ppm or less.

2. The sputtering target according to 1, wherein the ratio of the Zr element to the total metal element is 50 ppm or more and 1000 ppm or less.

3. The sputtering target according to 1 or 2, wherein the average crystal grain size is from 2 μm to 10 μm.

4. The sputtering target according to any one of 1 to 3, wherein the relative density is 95% or more.

5. The sputtering target according to any one of 1 to 4, wherein the bulk resistance value is 50 m Ωcm or less.

6. The method for producing a sputtering target according to 1, comprising the step of causing a ratio of a Sn element to a total of a metal element in the sputtering target to be more than 2000 ppm and not more than 20,000 ppm, and the Zr element is relative to all the metal elements. a mixture of the indium raw material, the zinc raw material, the Sn raw material, and the Zr raw material is mixed and mixed to form a mixture; the mixture is molded to obtain a molded product; and the molded product is sintered at 1200 ° C to 1600 ° C for 1 hour. ~50 hours.

A method for producing an oxide film, comprising forming a film by using a sputtering target according to any one of 1 to 5.

8. An oxide film produced by the method described in 7.

9. The oxide film according to 8, which is a transparent conductive film.

An electronic device using an oxide film as described in 8 or 9.

Further, according to another aspect of the present invention, the following sputtering target, a method of manufacturing the same, and the like are provided. In this aspect, even if the sputtering target does not contain Zr as an essential component, the color unevenness of the target surface disappears. Therefore, the cutting amount of the target surface can be reduced, and the manufacturing station time can be shortened. And can improve yield.

A sputtering target comprising a hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m (in the formula, m = 2 to 7 integer), in which indium oxide and zinc oxide are main components, Sn The content is more than 2000 ppm and is less than 20,000 ppm. The difference between the maximum chromaticity and the minimum chromaticity of the surface formed by surface or arbitrarily cut is Δb* value of 0 to 5, and the average crystal grain size is 2 μm to 10 μm.

2. The sputtering target according to 1, wherein the maximum chromaticity b* value of the surface formed by the surface or any dicing is 14 or less.

3. The sputtering target according to 1 or 2, wherein the sputtering target containing Sn at a content of 2100 ppm, 2700 ppm or 3400 ppm is excluded.

4. The sputtering target according to any one of 1 to 3, wherein the relative density is 95% or more.

5. The sputtering target according to any one of 1 to 4, wherein the bulk resistance value is 50 m Ωcm or less.

6. A method for producing a sputtering target, wherein the difference between the maximum chromaticity and the minimum chromaticity of the surface formed by the surface or the arbitrary dicing is Δb* value of 0 to 5, and the average crystal grain size is 2 μm to 10 μm. a method for producing a target, comprising the steps of: mixing an indium raw material, a zinc raw material, and a Sn raw material to form a mixture so that a content of Sn of the sputtering target is more than 2000 ppm and not more than 20,000 ppm; and molding the mixture to prepare a molded product; The molded article is sintered at 1200 ° C to 1600 ° C for 1 hour to 50 hours.

A method for producing an oxide film, comprising forming a film by using a sputtering target according to any one of 1 to 5.

8. An oxide film produced by the method described in 7.

An oxide sintered body comprising indium oxide and zinc oxide as a main component, and a hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m (wherein m = 2 to 7 is an integer). The Sn content is more than 2000 ppm and is 20,000 ppm or less, and the difference between the maximum chromaticity and the minimum chromaticity of the unpolished surface or the surface formed by any dicing is Δb* value is 0 to 10, and the average crystal grain size is 2 μm to 10 μm.

10. The oxide sintered body according to 9, wherein the uncolored surface or the surface formed by any dicing has a maximum chromatic b* value of 20 or less.

According to the present invention, by setting the ratio of the Sn element to all the metal elements to more than 2000 ppm and 20000 ppm or less (more than 2000 ppm to 20,000 ppm) and containing Zr, generation of color unevenness on the surface of the sintered body can be suppressed, and the manufacturing time can be improved. Station time and yield, and suppress the amount of particles when sputtered into a film.

The sputtering target according to an embodiment of the present invention contains indium oxide and zinc oxide as main components and contains a hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m [wherein m is an integer of 2 to 7] Further, it contains a Sn element and a Zr element. Further, it is characterized in that the ratio of the Sn element to the total metal element is more than 2000 ppm and is 20,000 ppm or less.

The hexagonal layered compound contained in the sputtering target of the present invention is identified by an X-ray diffraction method and is represented by a compound of In ₂ O ₃ (ZnO) _m . In the formula, m is an integer of 2 to 7, preferably an integer of 3 to 5. The compound in which m is 1 does not adopt a hexagonal layered structure, and the compound in which m exceeds 7 has a hexagonal layered structure, but its bulk resistance is high.

The ratio of the Sn element contained in the sputtering target to all the metal elements is more than 2,000 ppm to 20,000 ppm.

If the ratio of the Sn element is 2000 ppm or less, color unevenness occurs when the target is sintered. The rate is reduced. In addition, when it exceeds 20,000 ppm, the oxide film (transparent conductive film) formed using the sputtering target is difficult to be etched by a weak acid such as oxalic acid. The content ratio of the Sn element is preferably more than 2,000 ppm to 20,000 ppm, 2050 ppm to 10,000 ppm, more than 2,100 ppm to 5,000 ppm, or 3,500 ppm to 5,000 ppm.

The ratio of the Zr element contained in the sputtering target to all the metal elements is preferably 50 ppm or more and 1000 ppm or less. If it is this range, the amount of fine particles at the time of sputtering film formation can be suppressed, and the yield of a transparent conductive film improves. Further, the resistance of the transparent conductive film formed by using the sputtering target does not rise, and etching can be performed by a weak acid such as oxalic acid, and no residue remains.

The ratio of the Zr element is preferably from 70 ppm to 700 ppm, and more preferably from 100 ppm to 500 ppm.

The ratio (ppm) of the Sn and Zr elements contained in the sputtering target with respect to all the metal elements can be measured by ICP (Inductively Coupled Plasma) emission spectrometry. Furthermore, the ratio of the Sn and Zr elements is approximately the same as the blending ratio in the target material.

In the present invention, when the ratio of the Sn element to the total of the metal elements is increased, particles are easily generated when the film is formed by sputtering. On the other hand, by adding the Zr element, the amount of generation of particles is suppressed. Although the mechanism of this effect is not necessarily clear, it is estimated that the additive effect of the Zr element acts on the extremely fine structure in the target. In other words, when the addition ratio of the Sn element is increased, zinc oxide as a target material is selectively reacted with tin oxide to produce a spinel phase having a high bulk resistance value. Therefore, it is considered that micro-arc is generated when the film is formed by sputtering, and the amount of particles is increased.

On the other hand, it is presumed that by the addition of the Zr element, the selective reaction of zinc oxide with tin oxide is suppressed, and the solid solution of the Sn element to the indium oxide is promoted.

By setting the ratio of the Sn element to the total metal element within the above range, generation of a surface uneven color layer of the sintered body can be suppressed, the amount of polishing can be reduced, and an industrially applicable station time can be secured.

On the other hand, by adding a Zr element, the amount of fine particles at the time of sputtering film formation which is increased by the addition of the Sn element can be suppressed.

Further, in the present invention, by setting the content ratio of the Sn element within the above range, the bulk resistance of the sputtering target can be sufficiently lowered. The bulk resistance of the sputtering target of the present invention is preferably 50 m Ω cm or less, 25 m Ω cm or less, 10 m Ω cm or less, or 5 m Ω cm or less. On the other hand, when the bulk resistance of the sputtering target exceeds 50 mΩcm, it is difficult to form a film stably by DC sputtering. Further, the lower limit is not particularly limited, and is usually about 0.1 mΩcm.

Further, the transparent conductive film formed by using the target can be etched by a weak acid such as oxalic acid.

The sputtering target of the present invention preferably has an average crystal grain size of from 2 μm to 10 μm, more preferably from 2 μm to 8 μm, from the viewpoint of preventing abnormal discharge.

The average crystal grain size can be adjusted depending on the conditions of the raw material or the production method. Specifically, it can be reduced according to the case of using a raw material having a small average particle diameter, for example, a raw material of 0.01 to 10 μm, preferably 5 μm or less, or a pulverization condition. On the other hand, at the time of sintering, the sintering temperature is higher and the sintering time is longer, and the average crystal grain size tends to be larger.

The average crystal grain size was measured by the following method.

In the case where the shape of the sputtering target is circular, the square inscribed with the circle is equally divided into 16 portions, 16 portions at the center point of each square, and the shape of the sputtering target is a quadrangle. In the case of the case, it is decided to divide the sides into four equal parts, and the opposite points are connected to each other and are equally divided into 16 parts, and 16 points at the center point of each square are placed on the surface in a frame of 1000 times magnification. Scanning electron microscope (SEM) observation was performed. The particles observed in the center of the field of view of 120 × 80 μm square were measured for all the particle diameters, and the average value was determined. The average value of the particle diameters was determined from all the average values of the 16 sites. The particle size is measured based on JIS R 1670, and the crystal grain size is taken as a circle-equivalent diameter.

The relative density of the sputtering target is preferably 95% or more, more preferably 96% or more. Since such a high-density target has high mechanical strength and excellent electrical conductivity, it can be further improved by being mounted on an RF (Radio Frequency) magnetron sputtering device or a DC magnetron sputtering device for sputtering. stability. The relative density is a value obtained by dividing the actual measured density of the sputtering target measured by the Archimedes method by the theoretical density calculated from the true density and weight ratio of the oxide of each constituent element. More specifically, it is calculated with reference to Japanese Patent Laid-Open Publication No. 2002-30429.

In the sputtering target of the present invention, the atomic ratio of indium to zinc is usually In / (In + Zn) = 0.2 to 0.95, preferably In / (In + Zn) = 0.3 to 0.9.

The sputtering target of the present invention contains indium oxide and zinc oxide as main components. Specifically, it includes indium oxide and zinc oxide, a predetermined amount of tin oxide which suppresses generation of a color unevenness layer, a predetermined amount of zirconia which suppresses the amount of fine particles, and impurities which are unavoidable other than these.

The total content of indium oxide and zinc oxide is more than 95% by weight, and is 97% by weight or more, and more preferably 98% by weight or more. Insofar as the effects of the present invention are not impaired, inevitable impurities may be contained in addition to the metal oxides.

The sputtering target of the present invention can be manufactured by mixing and pulverizing an indium raw material, a zinc raw material, a tin raw material, and a zirconium raw material; forming a raw material mixture; sintering the molded product; annealing the sintered body as needed; grinding the sintered body; and cutting The shape is specified.

The raw material is not particularly limited, and a compound or a metal containing an element of In, Zn, Sn or Zr, preferably an oxide, may be used.

A raw material such as indium oxide, zinc oxide, tin oxide or zirconium oxide is preferably used in a high purity, and a purity of 99% or more, preferably 99.9% or more, and more preferably 99.99% or more is preferably used. When a high-purity raw material is used, a fine sintered body is obtained, and the volume resistance is lowered.

Further, the average particle diameter of the metal oxide of the raw material is preferably 0.01 to 10 μm, more preferably It is 0.05 to 5 μm, and more preferably 0.1 to 5 μm. When the average particle diameter is less than 0.01 μm, aggregation tends to occur, and if it exceeds 10 μm, the miscibility is insufficient, and a sintered body having a fine structure cannot be obtained.

A binder such as polyvinyl alcohol or vinyl acetate may be added to the raw material.

The mixing of the raw materials can be carried out by a usual mixing pulverizer such as a ball mill, a jet mill or a bead mill.

The mixture thus obtained can be directly molded, or can be calcined before it is molded. The calcination treatment is usually carried out at 700 to 900 ° C for 1 to 5 hours.

The mixture of the raw material powder or the calcined metal oxide powder improves the fluidity or filling property in the subsequent molding step by performing the granulation treatment. The granulation treatment can be carried out using a spray dryer or the like. The particle size of the granulated product formed by the granulation treatment is preferably from 1 to 100 μm, more preferably from 5 to 100 μm, still more preferably from 10 to 100 μm.

Next, the powder or granulated material of the raw material is molded by a method such as press molding, casting molding, or injection molding in a molding step. In the case where a sintered body having a high sintered density is obtained as a sputtering target, it is preferably pre-molded by press molding or the like in the molding step, and then compacted by cold-pressure press molding or the like. Chemical.

In the sintering step of the molded body, a usual sintering method such as normal pressure sintering, hot press sintering, or hot press pressure sintering can be used. The sintering temperature is preferably from 1200 to 1600 ° C, more preferably from 1250 to 1550 ° C, and still more preferably from 1300 to 1500 ° C. If the sintering temperature is less than 1200 ° C, a sufficient sintered density cannot be obtained. If the temperature exceeds 1600 ° C, the composition of the metal oxide in the obtained sintered body may be changed by sublimation of indium oxide or zinc oxide. . The temperature increase rate at the time of sintering is preferably from 0.1 to 3 ° C/min from 800 ° C to the sintering temperature.

The sintering time varies depending on the sintering temperature, and is preferably from 1 to 50 hours, more preferably from 2 to 30 hours, and still more preferably from 3 to 20 hours. The environment during sintering may be air or oxygen, or may be a reducing gas such as hydrogen, methane gas or carbon monoxide gas, or argon gas, nitrogen gas, or the like. Inert gas.

The sintered body can also be annealed. The annealing treatment is usually carried out at 700 to 900 ° C for 1 to 5 hours.

The color unevenness layer on the surface of the oxide sintered body immediately after sintering thus obtained is measured by the method described in the examples to measure b* and Δb* to be polished until the surface after polishing becomes b*≦4 and Δb*≦2. The depth of the grinding (the thickness of the uneven layer of color) is defined. The polishing depth is preferably 0 to 0.7 mm, more preferably 0 to 0.5 mm, and particularly preferably 0 to 0.3 mm.

The sputtering target can be formed by cutting the sintered body obtained above into an appropriate shape.

The sputtering target according to another embodiment of the present invention contains indium oxide and zinc oxide, and contains a hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m [wherein m is an integer of 2 to 7]. Further, it contains more than 2,000 ppm to 20,000 ppm (by weight) of Sn.

The hexagonal layered compound containing indium oxide and zinc oxide is the same as the above embodiment.

The ratio of Sn contained in the sputtering target is more than 2000 ppm to 20,000 ppm.

When the ratio of Sn is 2000 ppm or less, color unevenness occurs at the time of target sintering, and the yield is lowered. In addition, when the amount is more than 20,000 ppm, the transparent conductive film formed by using the sputtering target is difficult to be etched by a weak acid such as oxalic acid. The content ratio of Sn is preferably more than 2,000 ppm to 20,000 ppm, 2050 ppm to 10,000 ppm, more than 2,100 ppm to 5,000 ppm, or 3,500 ppm to 5,000 ppm.

By setting the content of Sn within the above range, the unevenness of the color of the target surface can be reduced during sintering, and the amount of cut can be reduced because the color of the interior and the surface are not easily different.

Further, in the present invention, by setting the content ratio of Sn within the above range, the bulk resistance of the sputtering target can be sufficiently lowered. The bulk resistance of the sputtering target of the present invention is preferably 50 m Ω cm or less, 25 m Ω cm or less, 10 m Ω cm or less, or 5 m Ω cm or less. On the other hand, when the body resistance of the sputtering target exceeds 50 mΩcm, it is difficult to stabilize by DC sputtering. Set it into a film.

Further, the transparent conductive film formed by using the target film can be easily subjected to etching processing by a weak acid such as oxalic acid.

The average crystal grain size of the sputtering target of the present invention is preferably from 2 μm to 10 μm, more preferably from 2 μm to 8 μm, from the viewpoint of abnormal discharge.

The average crystal grain size can be adjusted depending on the conditions of the raw material or the production method. Specifically, a raw material having a small average particle diameter, for example, a raw material of 0.01 to 10 μm, preferably 5 μm or less, and more preferably 1 μm or less is used. Further, at the time of sintering, the sintering temperature is higher and the sintering time is longer, and the average crystal grain size tends to be larger.

The relative density of the sputtering target is preferably 95% or more, more preferably 96% or more. With such a density, the target has high mechanical strength and excellent electrical conductivity, so that it is possible to further improve the stability when it is mounted on an RF magnetron sputtering device or a DC magnetron sputtering device for sputtering.

Further, the measurement of the average crystal grain size and the relative density is the same as in the above embodiment.

In the sputtering target of the present invention, the atomic ratio of indium to zinc is usually In / (In + Zn) = 0.2 to 0.95, preferably In / (In + Zn) = 0.3 to 0.9.

The sputtering target of the present invention contains indium oxide and zinc oxide as main components. Specifically, indium oxide and zinc oxide may account for 90% by weight or more, 95% by weight or more, 97% by weight or more, 98% by weight or more, or 98.5% by weight or more.

Alternatively, the metal element contained in the sputtering target of the present invention substantially contains In, Zn, and Sn, and may contain unavoidable impurities in addition to the metal oxides without departing from the effects of the present invention.

In the present invention, "substantially" means that the effect of the sputtering target is caused by the oxide of In, Zn, and Sn, or 90 atom% or more and 95 atom% or more of all the metal elements of the sputtering target. 97 atom% or more, 98 atom% or more, 99 atom% or more, or 99.5 atom% or more, and 100 atom% or less is In, Zn, and Sn.

The sputtering target of the present invention can be manufactured by the following steps: mixing indium raw materials, zinc raw materials And a raw material of Sn; molding the raw material mixture; sintering the molded product; and annealing the sintered body as needed. Specifically, the method of the above-described embodiment of the present invention is the same except that the Zr element is not required.

The color unevenness of the surface of the oxide sintered body in the present embodiment or the surface formed by any dicing is preferably Δb* measured by the method described in the examples, preferably 0 to 10, more preferably 0 to 5. Especially good is 0~4. Further, the maximum b* value of the surface of the surface of the unpolished oxide sintered body or the surface formed by any dicing is preferably 20 or less, more preferably 19 or less, and still more preferably 18 or less.

The sputtering target can be formed by cutting the sintered body obtained above into an appropriate shape.

The Δb* measured by the method described in the examples is preferably 0 to 5, and more preferably 0 to 3, with respect to the color unevenness of the surface thus obtained or the surface formed by any dicing. Further, the maximum b* of the surface after polishing or the surface formed by any dicing is preferably 14 or less, more preferably 12 or less, and still more preferably 10 or less.

The oxide film of the present invention is obtained by forming a film by a sputtering method using the sputtering target of the present invention described above.

The film formation by the sputtering method can be preferably carried out by RF magnetron sputtering, DC magnetron sputtering, etc., and in terms of productivity, DC magnetron sputtering is generally applied. The film forming conditions are also not particularly limited, and a film can be preferably formed under the conditions of usual application.

Example

Examples 1 to 9 and Comparative Examples 1 to 4

Weighing 5000 g of indium oxide powder having an average surface area of 11 m ² /g, an average particle diameter of 0.98 μm, and 600 g of zinc oxide powder having the same specific surface area and average particle diameter, and further obtaining the content in the sputtering target as shown in Table 1. Tin oxide and zirconium oxide were weighed so as to show the content (ppm = Sn or Zr / all metal elements (In + Zn + Sn + Zr) × 10 ⁶ ), and the binder for molding was added to uniformly mix and granulate.

In addition, the average particle diameter of each powder was measured by the laser diffraction type particle size distribution measuring apparatus SALD-300V (made by Shimadzu Corporation), and the average particle diameter was the median diameter D50.

Next, the granulated product was uniformly filled into a mold, and pressure-molded at 50 MPa by a cold press, and then press-molded at 200 MPa by a cold equalizing press. The molded body thus obtained was sintered in a sintering furnace at 1400 ° C (temperature rising rate from 800 ° C to the sintering temperature: 2 ° C / min) for 20 hours.

Regarding the obtained sintered body, the crystal structure was examined by an X-ray diffraction measuring apparatus (XRD, X-ray diffractometer). As a result, in all of the examples and the comparative examples, the presence of the hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m (wherein m = 2 to 7 integers) was confirmed. The measurement conditions of XRD are as follows.

. Device: Ultima-III manufactured by Rigaku Co., Ltd.

. X-ray: Cu-Kα ray (wavelength 1.5406 Å, monochromatized with graphite monochromator)

. 2θ-θ reflection method, continuous scanning (1.0°/min)

. Sampling interval: 0.02°

. Slit DS, SS: 2/3°, RS: 0.6 mm

Further, the following characteristics were measured for the obtained sintered body. The results are shown in Table 1.

(1) Chromaticity (b* value) and grinding depth

The chromaticity (b* value) of the oxide sintered body immediately after sintering and the surface of the sintered oxide sintered body after the sintering was measured by a colorimetric color difference meter (NR-11A manufactured by Nippon Denshoku Co., Ltd.). Observe the surface of the oxide sintered body, and visually determine the portion where the yellow tone is deep (b* highest value: maximum b*) and the portion where the yellow tone is lighter and the dark green color becomes blackened (b* lowest value). Poor (△b*). The depth of the polishing was measured by using a vernier caliper to determine the depth when b*≦4 and Δb*≦2 or less were used as the thickness before and after, and the difference was obtained from the difference.

(2) Average crystal grain size (μm)

Regarding the average crystal grain size of the tetragonal sputtering target, it is decided to divide each side into four equal parts. The points were joined to each other and divided into 16 sections in equal areas, and 16 points in the center point of each quadrangle were observed by scanning electron microscopy (SEM) on the surface in a frame at a magnification of 1000 times. The particles observed in the center portion of the field of view at 120 × 80 μm square were measured, and the average particle diameter was measured, and the average value was determined. The average value of the particle diameters was determined from all the average values of the 16 sites. The particle size is measured based on JIS R 1670, and the crystal grain size is taken as a circle-equivalent diameter.

(3) Body resistance value (mΩcm)

The bulk resistance (conductivity) of the target was measured based on a four-probe method using a resistivity meter (manufactured by Mitsubishi Chemical Corporation, Loresta).

(4) Relative density

The actual density measured by the Archimedes method is divided by the theoretical density calculated from the true density and weight ratio of the oxides of the constituent elements, thereby calculating the relative density (refer to Japanese Patent Laid-Open No. 2002-30429). Bulletin).

(5) Etching speed and residue

The sputtering target was mounted on a DC magnetron sputtering apparatus and sputtered for 10 minutes under the conditions of a sputtering pressure of 0.3 Pa, a sputtering power of 100 W, and an argon gas of 100%, and the entire surface of the surface of the glass substrate of 100 mm □ was formed. A transparent conductive film having a film thickness of 100 nm.

Under the film formation conditions, an indium zinc oxide film having a thickness of 100 nm was formed on a glass substrate, and then immersed in a commercially available oxalic acid etching solution (ITO-06N: manufactured by Kanto Chemical Co., Ltd.) at 30 ° C until the resistance of the substrate. The value becomes infinite, and the etching time is obtained by dividing the initial film thickness (100 nm) by the time required for the resistance value of the substrate to become infinite.

In addition, five sheets of a substrate of 100 mm □ were immersed in an oxalic acid etching liquid in the same manner as described above until the resistance value of the substrate became infinite, and then washed with pure water and dried, and then observed at 10,000 times by a scanning electron microscope. Count the number of residues in the center of the field of view 10 × 8 μm square. The observation is performed at a total of five points at the intersection of the diagonal lines of the respective substrates and the center point of the intersection and the apex, and the residual residue is obtained from the average of the five pieces. The number is defined as an etching residue in the following manner.

. Etching residue evaluation standard

○: 3 or less

△: 4 or more, 7/100 or less

×: 8 or more

The etching residue usually has a space in the form of particles remaining in the space portion of the etching process to cause a short circuit. The attachment of such particles is undesirable because it significantly reduces the yield of the component. In the case of a small number of cases, it can be normalized by the repairing step, but when the number is increased, it is difficult to repair and reduce the yield of the component.

(6) Average number of particles

In the same manner as in the above (5), a transparent conductive film having a thickness of 100 nm was deposited and attached to the transparent conductive film by a particle counter (FPD (Flat Panel Display) inspection apparatus Capricorn manufactured by V-TECHNOLOGY Co., Ltd.). The maximum diameter is 0.5 μm or more. Each of the targets was repeatedly formed into a film 5 times, and the average of the obtained numbers was taken as the average number of particles. The evaluation is as follows.

. Evaluation criteria for particles

○: 5/100mm□ or less

△: 6 pieces/100 mm□ or more and 9 pieces/100 mm□ or less

×: 10 / 100mm □ or more

When the particles generated on the film-forming substrate are sputtered by sputtering, there is an open circuit (broken wire) when the film is peeled off by the etching process in the next step, and when it is left in the form of particles, there is Short circuit condition. Wiring abnormalities caused by such particles are not preferable because the component yield is significantly lowered. In the case of a small number of cases, it can be normalized by the repairing step, but when the number is increased, it is difficult to repair and reduce the yield of the component.

Reference Examples 1 to 4, Reference Comparative Examples 1 to 3

Weighing an indium oxide powder having an average surface area of 11 m ² /g, an average particle size of 0.98 μm, and a zinc oxide powder having an average specific surface area and an average particle diameter of 600 g, and further obtaining the content in the sputtering target as shown in Table 2 The tin oxide was weighed by the content (weight of Sn), and the binder for molding was added to uniformly mix and granulate.

In addition, the average particle diameter of each powder was measured by the laser diffraction type particle size distribution measuring apparatus SALD-300V (made by Shimadzu Corporation), and the average particle diameter was the median diameter D50.

Next, the granulated product was uniformly filled into a mold and pressure-molded by a cold press. The molded body thus obtained was sintered in a sintering furnace at 1400 ° C (temperature rising rate from 800 ° C to the sintering temperature: 2 ° C / min) for 20 hours.

With respect to the obtained sintered body, the crystal structure was examined by XRD in the same manner as in Example 1. As a result, the presence of the hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m (where m is an integer of 2 to 7) was confirmed in all cases.

Further, with respect to the obtained sintered body, the chromaticity (b* value), the average crystal grain size, and the bulk resistance value were measured in the same manner as in the examples. The results are shown in Table 2. Furthermore, the depth of the grinding is the depth of any grinding.

From the above results, it was confirmed that in order to reduce the color unevenness of the target surface, it is necessary to add more than 2000 ppm of Sn element.

On the other hand, as the content of the Sn element is increased (in a large amount), Δb* can be further reduced, but even if it exceeds 20,000 ppm, a large improvement effect of Δb* obtained by an increase in the Sn element content is not observed. As described above, in the case where more than 20,000 ppm of the Sn element is added, the etching characteristics of the film obtained by the sputtering target may be hindered, so that the excessive addition is not preferable.

From the above, it has been confirmed that the content of the Sn element is set to be in the range of more than 2,000 ppm to 20,000 ppm in order to reduce the bulk resistance value and maintain the characteristics of the indium zinc oxide.

Moreover, it was confirmed that the amount of etching residue and fine particles at the time of sputtering film formation can be suppressed by adding Zr.

[Industrial availability]

The transparent conductive film produced by using the sputtering target of the present invention can be used for a solar cell, a display device such as a liquid crystal, an organic electroluminescence or an inorganic electroluminescence, or an electronic device such as a touch panel. Further, the oxide film of the present invention can be used as a semiconductor film or the like for a thin film transistor.

The embodiments and/or the embodiments of the present invention are described in detail above, but the embodiments and/or embodiments as the examples are readily possible without departing from the novel teachings and effects of the present invention. Make a lot of changes. Accordingly, such numerous modifications are included within the scope of the invention.

The contents of the Japanese application form which will be the basis of Paris's priority in this case are all cited herein.

Claims (10)

A sputtering target comprising a hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m (in the formula, m = 2 to 7 integer) and containing Sn as a main component of indium oxide and zinc oxide. The ratio of the element and the Zr element to the total of the metal element is more than 2000 ppm and is 20,000 ppm or less. The sputtering target according to claim 1, wherein a ratio of the Zr element to the total metal element is 50 ppm or more and 1000 ppm or less. A sputtering target according to claim 1 or 2, wherein the average crystal grain size is from 2 μm to 10 μm. A sputtering target according to claim 1 or 2, wherein the relative density is 95% or more. A sputtering target according to claim 1 or 2, wherein the bulk resistance value is 50 m Ω cm or less. A method for producing a sputtering target, which is a method for producing a sputtering target according to claim 1, and comprising the steps of: making a ratio of a Sn element to a total metal element in the sputtering target more than 2000 ppm and less than 20,000 ppm And mixing the pulverized indium raw material, the zinc raw material, the Sn raw material, and the Zr raw material to form a mixture, and forming the molded product by molding the mixture; and 1200 ° C to 1600 The above shaped product was sintered at ° C for 1 hour to 50 hours. A method of producing an oxide film, which is formed by using a sputtering target according to any one of claims 1 to 5. An oxide film produced by the method of claim 7. The oxide film of claim 8, which is a transparent conductive film. An electronic machine using the oxide film of claim 8 or 9.