JP2020033639A - Oxide sputtering target and method for manufacturing the same - Google Patents

Abstract

To provide an oxide sputtering target capable of stably depositing a film by sputtering even when the sputtering surface of the target is comparatively large, and a method for manufacturing the oxide sputtering target.SOLUTION: The oxide sputtering target consists of an oxide including zirconium, silicon and indium as a metal component. The variation of density in the sputtering surface of the target is 3% or less, and the variation of density in the thickness direction is 5% or less.SELECTED DRAWING: None

Description

  The present invention relates to an oxide sputtering target composed of an oxide containing zirconium, silicon and indium as metal components, and a method for producing the oxide sputtering target.

In a display panel such as a liquid crystal display, an organic EL display, and a touch panel, a shield layer is provided in order to prevent a malfunction due to charging of a liquid crystal element or an organic EL element. In particular, in the in-cell type touch panel, the above-described shield layer is required to have an action of causing a touch signal to reach a sensor portion inside the panel while eliminating external noise.
The shield layer is also required to have high visible light transmittance in order to ensure the visibility of the display panel.

Here, for example, Patent Document 1 proposes a transparent conductive film mainly containing indium tin oxide (ITO) as the above-mentioned shield layer.
By the way, a transparent conductive film containing indium tin oxide (ITO) as a main component has a low transmittance with respect to visible light, so that the transparent conductive film looks yellowish and visibility may be deteriorated. Was.

Therefore, it is conceivable to apply an oxide film containing zirconium, silicon and indium as metal components as the above-mentioned shield layer.
For example, Patent Documents 2 to 4 propose an oxide sputtering target used when forming an oxide film containing zirconium, silicon, and indium as metal components.

JP 2013-142194 A JP 2007-327103 A JP 2009-062585 A JP 2018-040032 A

By the way, the oxide sputtering targets disclosed in Patent Documents 2-4 mainly assume that a dielectric layer and a protective layer of an optical disk as an information recording medium are formed, and the target sputtering surface is compared. Was very small.
Here, when forming a shield layer such as an in-cell type touch panel, it is preferable to use a large sputtering target or a cylindrical sputtering target having a large target sputtering surface area.
In Patent Documents 2 to 4 described above, when a large-sized sputtering target is manufactured, the firing is insufficient, a variation in density or a variation in oxygen concentration occurs, or a crack or warpage occurs. There is a possibility that a sputter film cannot be stably formed.

  The present invention has been made in view of the above-described circumstances, and has an oxide sputtering target capable of stably forming a sputter film even when a target sputtering surface is relatively large, and an oxide sputtering target having the same structure. An object of the present invention is to provide a method for manufacturing a target.

  In order to solve the above problems, the oxide sputtering target of the present invention is an oxide sputtering target composed of an oxide containing zirconium, silicon, and indium as a metal component, and has a variation in density in a target sputtering surface. It is characterized in that it is within 3% and the variation in density in the thickness direction is within 5%.

According to the oxide sputtering target of the present invention, since it is composed of an oxide containing zirconium, silicon and indium as the metal component, it has a high resistance, and has excellent visible light transmittance, and is suitable for the shield layer. This makes it possible to form an oxide film.
Since the variation in the density within the target sputtering surface is set to 3% or less, the sputtering is stable on the entire target sputtering surface during the sputtering film formation, and the oxide film can be stably formed.
In addition, since the variation in the density in the thickness direction is within 5%, an oxide film can be formed stably even when sputtering proceeds.

Here, in the oxide sputtering target of the present invention, it is preferable that the variation of the specific resistance in the target sputtering surface be within 10% and the variation of the specific resistance in the thickness direction be within 10%.
In this case, since the variation in the specific resistance within the target sputtering surface is set to be within 10%, it is possible to suppress occurrence of abnormal discharge during sputtering.
Further, since the variation in the specific resistance in the thickness direction is set to be within 10%, the oxide film can be stably formed even when the sputtering proceeds.

In the oxide sputtering target of the present invention, the area of the target sputtering surface may be 0.02 m ² or more.
In this case, since the area of the target sputtering surface is relatively large at 0.02 m ² or more, an oxide film can be formed over a large-area substrate. Note that the oxide sputtering target may have a flat plate shape or a cylindrical shape.

  The method for producing an oxide sputtering target of the present invention is a method for producing an oxide sputtering target composed of an oxide containing zirconium, silicon and indium as metal components, comprising zirconium oxide powder, silicon oxide powder and indium oxide powder. And a sintering step of sintering the obtained sintering material powder to obtain a sintered body. The bonding step is characterized by heating while introducing oxygen, maintaining the temperature in a temperature range of 1200 ° C. or more and 1400 ° C. or less for 3 hours or more, and then heating and maintaining the temperature to a temperature exceeding 1400 ° C.

According to the method for manufacturing an oxide sputtering target having this configuration, in the sintering step, sintering is performed at 1200 ° C. or higher at which sintering of indium oxide in the sintering raw material powder is started, and sintering is performed by forming a composite oxide. Since the temperature is maintained in the temperature range of 1400 ° C. or less for 3 hours or more, it is possible to allow oxygen gas to permeate into the inside while maintaining the gap channel between the sintering raw material powders during sintering.
Then, by heating and holding the temperature to a temperature exceeding 1400 ° C., sintering can be progressed uniformly, and a sintered body having a small variation in density can be obtained.

Here, in the method for manufacturing an oxide sputtering target of the present invention, the median diameter (D50) of the sintering raw material powder is preferably in a range from 0.05 μm to 1.2 μm.
In this case, since the median diameter (D50) of the sintering raw material powder is relatively small in the range of 0.05 μm or more and 1.2 μm or less, the amount of shrinkage during sintering can be suppressed low, and large-sized oxide sputtering Even when the target is manufactured, generation of cracks and warpage can be suppressed, and the manufacturing yield can be improved.

  Advantageous Effects of Invention According to the present invention, it is possible to provide an oxide sputtering target capable of performing sputter deposition stably even when a target sputtering surface is relatively large, and a method for manufacturing the oxide sputtering target.

FIG. 1 is a schematic explanatory view of an oxide sputtering target according to one embodiment of the present invention. It is a flow figure showing the manufacturing method of the oxide sputtering target concerning one embodiment of the present invention. 4 is a temperature chart of a sintering step in the method for manufacturing an oxide sputtering target according to one embodiment of the present invention. It is a schematic explanatory view of an oxide sputtering target which is another embodiment of the present invention. It is a schematic explanatory view of an oxide sputtering target which is another embodiment of the present invention.

Hereinafter, an oxide sputtering target according to an embodiment of the present invention and a method for manufacturing the oxide sputtering target will be described with reference to the accompanying drawings.
The oxide sputtering target according to the present embodiment forms an oxide film suitable as a shield layer provided for preventing static electricity in a display panel such as a liquid crystal display panel, an organic EL display panel, and a touch panel. It is used at the time.

The oxide sputtering target according to the present embodiment is composed of an oxide containing zirconium, silicon and indium as metal components. The oxide sputtering target of the present embodiment has a composite oxide phase containing at least a part of the above-described metal elements and an indium oxide phase.
In the present embodiment, as shown in FIG. 1, a rectangular flat plate type sputtering target having a rectangular sputtering surface is used, and the area of the target sputtering surface is set to 0.02 m ² or more.

In the oxide sputtering target according to the present embodiment, the variation in density in the target sputtering surface is set to 3% or less, and the variation in density in the thickness direction is set to 5% or less.
In the present embodiment, the average value (average density) of the densities measured at a plurality of locations is set to 5.5 g / cm ³ or more.

Furthermore, in the oxide sputtering target according to the present embodiment, the variation of the specific resistance in the target sputtering surface is set to 10% or less, and the variation of the specific resistance in the thickness direction is set to 10% or less.
In the present embodiment, the average value (average specific resistance) of the specific resistance measured at a plurality of locations is set to 1.0 × 10 ⁻² Ω · cm or less.

  Hereinafter, in the oxide sputtering target of the present embodiment, the composition of the oxide, the phase configuration, the variation in the density in the target sputtering surface, the variation in the density in the thickness direction, the variation in the specific resistance in the target sputtering surface, the thickness The reason why the variation in the specific resistance in the direction is defined as described above will be described.

(Oxide composition)
The oxide sputtering target according to the present embodiment is composed of an oxide containing zirconium, silicon and indium as the metal component. In an oxide sputtering target having such a composition, it is possible to form an oxide film having a sufficiently high resistance value and excellent transmittance of visible light.
Here, in this embodiment, assuming that the total of the metal components is 100 mass%, the Zr content is in the range of 2 mass% to 27 mass%, the In content is in the range of 65 mass% to 95 mass%, It is preferable that the content is in the range of 0.5% by mass or more and 15% by mass or less, and is an unavoidable impurity metal element.

When the content of Zr is 2 mass% or more, the durability of the formed oxide film can be improved, and the hardness is increased and the oxide film is resistant to scratches. On the other hand, when the content of Zr is 27 mass% or less, an increase in the refractive index can be suppressed, and the occurrence of unnecessary reflection can be suppressed. Therefore, a decrease in the transmittance of visible light can be suppressed.
Note that the total of the metal components is 100 mass%, and the lower limit of the Zr content is preferably 5 mass% or more, and the upper limit of the Zr content is preferably 20 mass% or less.

When the In content is 65 mass% or more, the conductivity of the oxide sputtering target can be secured, and an oxide film can be formed by direct current (DC) sputtering. On the other hand, when the content of In is set to 95 mass% or less, a decrease in the transmittance of short wavelengths can be suppressed, and visibility can be secured.
The total of the metal components is 100 mass%, and the lower limit of the In content is preferably 75 mass% or more, and the upper limit of the In content is preferably 90 mass% or less.

When the Si content is 0.5 mass% or more, the flexibility of the oxide sputtering target can be ensured, and the crack resistance of the film is improved. On the other hand, when the content of Si is set to 15 mass% or less, a decrease in the conductivity of the film can be suppressed, and an oxide film can be formed by direct current (DC) sputtering.
Note that the total of the metal components is 100 mass%, and the lower limit of the Si content is preferably 2 mass% or more, and the upper limit of the Si content is preferably 7 mass% or less.

(Phase composition)
The oxide sputtering target according to the present embodiment has a composite oxide phase containing at least a part of the above-described metal elements and an indium oxide phase.
Here, due to the presence of the indium oxide phase, the resistance value of the oxide sputtering target of this embodiment is reduced, and the oxide film can be formed by direct current (DC) sputtering.

(Density variation)
If the density varies in the target sputtering surface, abnormal discharge may occur during sputtering film formation. In particular, in the present embodiment, since the area of the target sputtering surface is relatively large, that is, 0.02 m ² or more, the density in the target sputtering surface tends to vary. Therefore, in the present embodiment, the variation in density within the target sputtering surface is set to within 3%.

In addition, if the density varies in the thickness direction, abnormal discharge may occur during sputtering deposition when sputtering proceeds and the target sputtering surface is consumed. Therefore, in the present embodiment, the variation in the density in the thickness direction is set to 5% or less.
In the present embodiment, the variation in density is defined by the following equation from the maximum and minimum values of the density measured at a plurality of locations.
Variation in density = (maximum value-minimum value) / (maximum value + minimum value) x 100 (%)

  Here, as shown in FIG. 1A, the variation in the density of the oxide sputtering target is caused by a central portion (1) where diagonal lines intersect and four corner portions (2), (3), (4), Samples were collected from the five blocks of (5), and these five blocks were divided into three (α), (β), and (γ) blocks in the thickness direction as shown in FIG. Then, a total of 15 samples were collected, and the density of each sample was measured.

The variation in density in the target sputtering surface was calculated as follows. From the maximum value and the minimum value of the density in each block in the thickness direction for the five blocks in the target sputtering surface, the target in one block in the thickness direction (for example, five samples of α1 to α5) is obtained by the above equation. The density variation in the sputtering surface is calculated, and the average value of the density variations in the three blocks (α1 to α5 / β1 to β5 / γ1 to γ5) in the thickness direction is defined as the density variation in the target sputtering surface. .
That is, for the five blocks in the same horizontal plane, the density variation in the same horizontal plane is calculated from the maximum value and the minimum value of the density by the above equation, and further, the average value of the density variations calculated in each of the same horizontal planes Was defined as the density variation in the target sputtering surface.

Further, regarding the variation in the density in the thickness direction, for the three blocks in the thickness direction, the maximum value and the minimum value of the density of each block in the target sputtering surface are calculated from the maximum value and the minimum value of one block in the target sputtering surface by the above equation. The dispersion of the density in the thickness direction in one block (for example, three samples of α1 to γ1) is calculated, and the five blocks (α1 to γ1 / α2 to γ2 / α3 to γ3 / α4 to γ4 / α5) in the target sputtering surface are calculated. The average value of the density variations in the density variations in the thickness direction was defined as the density variation in the thickness direction.
That is, for the three blocks in the same vertical direction, the variation of the density in the same vertical direction is calculated from the maximum value and the minimum value of the density by the above equation, and the average value of the density variations calculated in the same vertical direction is calculated. Is defined as the density variation in the thickness direction.

Note that, in the oxide sputtering target according to the present embodiment, the average value (average density) of the densities measured for the 15 samples described above is 5.5 g / cm ³ or more. The average density is preferably 6.0 g / cm ³ or more, and more preferably 6.2 g / cm ³ or more.

(Dispersion of specific resistance)
If a variation in specific resistance occurs in the target sputtering surface, abnormal discharge may occur during sputtering film formation. In particular, in the present embodiment, since the area of the target sputtering surface is relatively large, that is, 0.02 m ² or more, the specific resistance tends to vary in the target sputtering surface. Therefore, in the present embodiment, the variation of the specific resistance in the target sputtering surface is set to 10% or less.

In addition, when a variation in specific resistance occurs in the thickness direction, abnormal discharge may occur during sputtering deposition when sputtering proceeds and the target sputtering surface is consumed. Thus, in the present embodiment, the variation of the specific resistance in the thickness direction is set to within 10%.
In the present embodiment, the variation of the specific resistance is defined by the following equation from the maximum and minimum values of the specific resistance measured at a plurality of locations.
Variation in specific resistance = (maximum value-minimum value) / (maximum value + minimum value) x 100 (%)

  Here, as shown in FIG. 1A, the variation in the specific resistance of the oxide sputtering target is caused by a central portion (1) where diagonal lines intersect and four corner portions (2), (3) and (4). , (5), samples are taken from the five blocks, and as shown in FIG. 1 (b), these five blocks are divided into three (three) in the thickness direction to collect a total of 15 samples. Then, the specific resistance of each sample was measured.

The variation in the specific resistance in the target sputtering surface was calculated as follows. From the maximum value and the minimum value of the specific resistance of each block in the thickness direction for the five blocks in the target sputtering surface, the above equation is used to calculate the value in one block in the thickness direction (for example, five samples of α1 to α5). The variation of the specific resistance in the target sputtering surface is calculated, and the average value of the specific resistance variation of the three blocks (α1 to α5 / β1 to β5 / γ1 to γ5) in the thickness direction is calculated as the specific resistance in the target sputtering surface. Was considered as the variation.
That is, for the five blocks in the same horizontal plane, the variation of the specific resistance in the same horizontal plane is calculated from the maximum value and the minimum value of the specific resistance by the above equation, and the variation of the specific resistance calculated in each of the same horizontal planes is calculated. The average value of was determined as the variation of the specific resistance in the target sputtering surface.

Further, regarding the variation of the specific resistance in the thickness direction, for the three blocks in the thickness direction, the maximum value and the minimum value of the specific resistance of each block in the target sputtering surface are calculated according to the above equation. Of the specific resistance in the thickness direction of one block (for example, three samples of α1 to γ1), and calculates five blocks (α1 to γ1 / α2 to γ2 / α3 to γ3 / α4 to The average value of the variation of the specific resistance of [gamma] 4 / [alpha] 5 to [gamma] 5) was defined as the variation of the specific resistance in the thickness direction.
That is, for the three blocks in the same vertical direction, the variation of the specific resistance in the same vertical direction is calculated from the maximum value and the minimum value of the specific resistance by the above equation, and the variation of the specific resistance calculated in the same vertical direction is further calculated. Was taken as the variation of the specific resistance in the thickness direction.

In the oxide sputtering target according to the present embodiment, the average value (average specific resistance) of the specific resistances measured for the 15 samples described above is 1.0 × 10 ⁻² Ω · cm or less. The average specific resistance is preferably 8.5 × 10 ⁻³ Ω · cm or less, more preferably 7.5 × 10 ⁻³ Ω · cm or less.

  Next, a method for manufacturing the oxide sputtering target according to the above-described embodiment will be described with reference to FIGS.

(Sintering raw material powder forming step S01)
First, zirconium oxide powder (ZrO ₂ powder), silicon oxide powder (SiO ₂ powder) and indium oxide powder (In ₂ O ₃ powder) are prepared.
Here, the zirconium oxide powder (ZrO ₂ powder), the silicon oxide powder (SiO ₂ powder), and the indium oxide powder (In ₂ O ₃ powder) each have a purity of 99.9% by mass or more and an average particle diameter of 0,9. It is preferable that the thickness be in the range of 1 μm or more and 20 μm or less. Note that the purity of the ZrO ₂ powder was calculated by measuring the contents of Fe ₂ O ₃ , SiO ₂ , TiO ₂ , and Na ₂ O, and determining that the balance was ZrO ₂ . The ZrO ₂ powder of the present embodiment may contain HfO ₂ at a maximum of 2.5%.

These oxide powders are weighed so as to have a predetermined composition ratio, and mixed using a pulverizer / mixer to form a sintering raw material powder.
Here, the sintering raw material powder preferably has a median diameter (D50) in a range of 0.05 μm or more and 1.2 μm or less.

(Molding step S02)
Next, the obtained sintering raw material powder is filled into a molding die and pressed to obtain a molded body having a predetermined shape. As a pressing method, a press, CIP, or the like is used. The pressurizing pressure at this time is preferably in the range of 20 MPa or more and 300 MPa or less. The temperature may be room temperature, but in order to improve the strength of the molded body, press forming at a temperature in the range of 900 ° C. or more and 950 ° C. or less promotes neck formation and improves the strength of the molded body. I do. Further, a pressure may be formed by adding a binder to the sintering raw material powder.

(Sintering step S03)
This compact is placed in a firing apparatus having an oxygen introduction function, and is heated and sintered while introducing oxygen. At this time, the amount of introduced oxygen is preferably in the range of 3 L / min to 10 L / min. Further, it is preferable that the heating rate be in the range of 50 ° C./h or more and 200 ° C./h or less.

Then, in the present embodiment, in the sintering step S03, as shown in FIG. 3, the temperature is maintained in a temperature range of 1200 ° C. or more and 1400 ° C. or less for 3 hours or more, and thereafter, a temperature exceeding 1400 ° C. (for example, 1500 ° C. or more) Heat and hold until the sintering of the compact proceeds.
Maintain at a temperature of 1200 ° C. or more, which is the temperature at which sintering of indium oxide powder in the sintering raw material powder is started, and 1400 ° C. or less, at which sintering proceeds due to formation of a composite oxide, for 3 hours or more. Thereby, it is possible to uniformly infiltrate the oxygen gas into the inside of the compact while maintaining the gap channel between the sintering raw material powders at the time of sintering. The upper limit of the holding time in the temperature range of 1200 ° C. to 1400 ° C. is not limited, but is preferably 15 hours or less from the viewpoint of working efficiency.
Thereafter, by heating and holding to a temperature exceeding 1400 ° C., the sintering of the molded body proceeds uniformly.

(Machining process S04)
Next, machining such as lathing is performed on the above-described sintered body to obtain an oxide sputtering target having a predetermined size.

  Through the above steps, the oxide sputtering target of the present embodiment is manufactured.

Then, an oxide film suitable as a shield layer for an in-cell type touch panel or the like is formed by sputtering using the oxide sputtering target of the present embodiment.
Here, in the oxide sputtering target according to the present embodiment, as described above, the resistance value is low due to the presence of the indium oxide phase, and the oxide film can be formed by direct current (DC) sputtering. Become.
On the other hand, the formed oxide film has a composite oxide phase as a whole, and has a sufficiently high resistance value, and is particularly suitable as a shield layer.

  According to the oxide sputtering target of the present embodiment having the above-described configuration, since the metal component is formed of an oxide containing zirconium, silicon, and indium, the resistance value is high, and visible. An oxide film having excellent light transmittance and suitable for a shield layer can be formed.

Since the variation in the density within the target sputtering surface is set to 3% or less, the sputtering is stable on the entire target sputtering surface during the sputtering film formation, and the oxide film can be stably formed.
In addition, since the variation in the density in the thickness direction is within 5%, an oxide film can be formed stably even when sputtering proceeds.

Furthermore, in the oxide sputtering target of the present embodiment, since the variation in the specific resistance within the target sputtering surface is set to be within 10%, it is possible to suppress occurrence of abnormal discharge during sputtering.
Further, since the variation in the specific resistance in the thickness direction is set to be within 10%, the oxide film can be stably formed even when the sputtering proceeds.

Furthermore, in the oxide sputtering target of the present embodiment, the area of the target sputtering surface is relatively large at 0.02 m ² or more, so that an oxide film can be formed on a large-area substrate. In addition, even with such a large oxide sputtering target, since the variation in density is specified as described above, a sputter film can be stably formed.

  Further, according to the method for manufacturing an oxide sputtering target of the present embodiment, in the sintering step S03, the sintering of indium oxide in the sintering raw material powder is started at 1200 ° C. or higher, and the composite oxide is Since the sintering is maintained at a temperature range of 1400 ° C. or less for 3 hours or more in which sintering proceeds by forming, oxygen gas is uniformly injected into the molded body while maintaining a gap channel between the sintering raw material powders during sintering. It is possible to penetrate. By heating and maintaining the temperature in this state up to a temperature exceeding 1400 ° C., sintering can be progressed uniformly in the molded body, and a sintered body in which variation in density is sufficiently suppressed can be obtained. It becomes possible.

  Further, in the present embodiment, since the median diameter of the sintering raw material powder is in the range of 0.05 μm or more and 1.2 μm or less in the sintering raw material powder forming step S01, the amount of shrinkage during sintering is suppressed to be low. Therefore, even when a large-sized oxide sputtering target is manufactured, generation of cracks and warpage can be suppressed, and manufacturing yield can be improved.

As described above, the embodiments of the present invention have been described, but the present invention is not limited thereto, and can be appropriately changed without departing from the technical idea of the present invention.
For example, in the present embodiment, as shown in FIG. 1, the target sputtering surface has been described as a rectangular flat plate type sputtering target having a rectangular shape. However, the present invention is not limited to this. As shown in FIG. A disk-shaped sputtering target having a circular surface may be used. Further, as shown in FIG. 5, a cylindrical sputtering target having a cylindrical target sputtering surface may be used.

  Here, in a disk-shaped sputtering target having a circular target sputtering surface, as shown in FIG. 4A, the center of the circle formed by the sputtering surface (1) and the center of the circle pass through and perpendicular to each other. Samples were taken from five blocks of the outer peripheral portions (2), (3), (4), and (5) on two straight lines, and these five blocks were thickened as shown in FIG. In the vertical direction, (α), (β), and (γ) are divided into three (divided into three) blocks, a total of 15 samples are collected, and the density and specific resistance of each sample are measured. By the method described in the section of the embodiment, the variation of the density in the target sputtering surface, the variation of the density in the thickness direction, the variation of the specific resistance in the target sputtering surface, and the variation of the specific resistance in the thickness direction are calculated. Prefer to There.

  In a cylindrical sputtering target having a target sputtering surface of a cylindrical surface, as shown in FIGS. 5A and 5B, the lower end portion A, the central portion B, and the upper end portion C in the axial direction each have a circular shape. Samples were collected from a total of 12 blocks at positions (1), (2), (3), and (4) at equal intervals (90 ° intervals) in the circumferential direction, and as shown in FIG. These twelve blocks are divided into three blocks (α), (β), and (γ) in the thickness direction (radial direction), and a total of 36 samples are collected. The density and specific resistance of the sample were measured, and the density variation in the target sputtering surface (in the cylindrical surface), the density variation in the thickness direction, and the target sputtering Variation in specific resistance (in cylinder plane), thickness direction It is preferable to calculate definitive variation in specific resistance, a.

  Hereinafter, results of a confirmation experiment performed to confirm the effectiveness of the present invention will be described.

<Oxide sputtering target>
As raw material powders, indium oxide powder (In ₂ O ₃ powder: purity 99.9% by mass or more, average particle size 1 μm) and silicon oxide powder (SiO ₂ powder: purity 99.8% by mass or more, average particle size 2 μm) And zirconium oxide powder (ZrO ₂ powder: purity 99.9% by mass or more, average particle size 2 μm). Note that the purity of the ZrO ₂ powder was calculated by measuring the contents of Fe ₂ O ₃ , SiO ₂ , TiO ₂ , and Na ₂ O, and determining that the balance was ZrO ₂ . The ZrO ₂ powder of the present embodiment may contain HfO ₂ at a maximum of 2.5% by mass. And these were weighed so that it might become a compounding ratio shown in Table 1.

As shown in Table 1, each weighed raw material powder was wet-pulverized using a basket mill using zirconia balls having a diameter of 2 mm as a grinding medium or a bead mill using zirconia balls having a diameter of 0.5 mm as a grinding medium. Mixed.
The obtained slurry was dried, and the zirconia balls were removed with a 250 μm sieve to obtain a sintering raw material powder. Table 1 shows the median diameter (D50) of the obtained sintering raw material powder.
The median diameter was determined by preparing 100 mL of an aqueous solution having a sodium hexametaphosphate concentration of 0.2%, adding 10 mg of the mixed powder to the aqueous solution, and using a laser diffraction scattering method (measurement apparatus: manufactured by Nikkiso Co., Ltd., Microtrac MT3000). The distribution was measured. A cumulative particle size distribution curve was created from the obtained particle size distribution to obtain a median diameter (D50).

The obtained sintering raw material powder was compacted to obtain a compact. Here, in a rectangular flat plate type sputtering target, press molding or CIP molding was performed using a molding die having a size of 165 mm × 298 mm. Here, the conditions for press molding were 920 ° C. and a pressure of 25 MPa, and the conditions for CIP molding were room temperature (25 ° C.) and a pressure of 100 MPa.
In the cylindrical sputtering target, press molding or CIP molding was performed using a mold having an outer diameter of 205 mm, an inner diameter of 165 mm, and a height of 200 mm. Here, the conditions for press molding were 920 ° C. and a pressure of 25 MPa, and the conditions for CIP molding were room temperature (25 ° C.) and a pressure of 100 MPa.

Then, the obtained molded body is charged into a firing device having an oxygen introduction function (internal volume of 27,000 cm ³ ), and is heated and sintered while introducing oxygen. At this time, the introduced amount of oxygen was 6 L / min. The rate of temperature rise was 120 ° C./h.
Then, at the time of raising the temperature of the sintering, the temperature was maintained under the conditions shown in Table 1, and then the main firing was performed under the firing conditions shown in Table 1, to obtain a sintered body.

  The obtained sintered body is subjected to wet grinding to have a size of 126 mm × 178 mm × 6 mmt in a rectangular flat plate type sputtering target, and has an outer diameter of 155 mm, an inner diameter of 135 mm and a height of 150 mm in a cylindrical type sputtering target. Four pieces were used to make the length 600 mm.

  The following items were evaluated about the obtained oxide sputtering target. Table 2 shows the evaluation results.

(Metal component composition)
A sample was cut out from the prepared oxide sputtering target, pulverized, pretreated with an acid, and analyzed for metal components of Zr, Si, and In by ICP-AES. The content of each metal component with respect to the content was calculated and is shown in Table 2.

(Sintered particle size)
A sample was cut out from the prepared oxide sputtering target, polished by wet polishing, and three COMPO images at a magnification of 3000 were photographed using an electron probe microanalyzer (EPMA) device. On the other hand, three arbitrary line segments were drawn, and the number of particles crossing each line was measured. By dividing the length of the line segment by the number of particles, the particle diameter of the sintered body in each line segment was calculated. This was performed on three images, and the average value of the obtained nine particle diameters is shown in Table 2.

(Density and density variation)
In the rectangular flat plate type sputtering target, when the X axis is in the 126 mm direction, the Y axis is in the 178 mm direction, and the center is (X, Y) = (0 mm, 0 mm) coordinates, (−58 mm, +84 mm), (−58 mm) , -84 mm), (0 mm, 0 mm), (+58 mm, +84 mm), and (+58 mm, -84 mm). The dimensional density was measured for a total of 15 samples obtained by dividing the obtained 5 blocks of 10 mm × 10 mm × 6 mmt into three (three) in the thickness direction. Table 2 shows the average values of the densities of these 15 samples.

  The variation in the density in the target sputtering surface was calculated as follows. From the maximum value and the minimum value of the density in each block in the thickness direction for five blocks in the target sputtering surface, the density in the target sputtering surface in one block in the thickness direction is calculated by the equation described in the embodiment. The variation was calculated, and the average value of the three blocks in the thickness direction was defined as the density variation in the target sputtering surface.

  The variation in the density in the thickness direction was calculated as follows. For the three blocks in the thickness direction, the density in the thickness direction for one block in the target sputtering surface is calculated from the maximum value and the minimum value of the density for each block in the target sputtering surface by the equation described in the embodiment. Was calculated, and the average value of the five blocks in the target sputtering surface was defined as the density variation in the thickness direction.

  In the cylindrical sputtering target, one end face of the cylindrical sputtering target is placed on the lower side, and in a plane perpendicular to the axis, the X axis is an arbitrary end face direction, the Y axis is an end face direction perpendicular to the X axis, When the Z axis is the axis direction and the center is (X, Y, Z) = (0 mm, 0 mm, 0 mm) coordinates, (−72.5 mm, 0 mm, −70 mm), (+72.5 mm, 0 mm, − 70mm), (0mm, -72.5mm, -70mm), (0mm, + 72.5mm, -70mm), (-72.5mm, 0mm, 0mm), (+ 72.5mm, 0mm, 0mm), (0mm, -72.5mm, 0mm), (0mm, + 72.5mm, 0mm), (-72.5mm, 0mm, + 70mm), (+ 72.5mm, 0mm, + 70mm), (0mm,- 2.5mm, + 70mm), cut (0mm, + 72.5mm, the block of 10mm × 10mm × 10mmt around the 12 points each + 70 mm). The dimensional density was measured for a total of 36 samples obtained by dividing the obtained 12 blocks of 10 mm × 10 mm × 10 mmt into three (three) in the thickness direction. Table 2 shows average values of the densities of these 36 samples.

  The variation in the density in the target sputtering surface was calculated as follows. From the maximum value and the minimum value of the density in each block in the thickness direction for 12 blocks in the target sputtering surface, the density in the target sputtering surface in one block in the thickness direction is calculated by the equation described in the embodiment. The variation was calculated, and the average value of the three blocks in the thickness direction was defined as the density variation in the target sputtering surface.

  The variation in the density in the thickness direction was calculated as follows. For the three blocks in the thickness direction, the density in the thickness direction for one block in the target sputtering surface is calculated from the maximum value and the minimum value of the density for each block in the target sputtering surface by the equation described in the embodiment. Was calculated, and the average value of twelve blocks in the target sputtering surface was defined as the density variation in the thickness direction.

(Specific resistance and variation of specific resistance)
Regarding the obtained oxide sputtering target, a low resistivity meter (Loresta manufactured by Mitsubishi Chemical Co., Ltd.) was used for 15 blocks similar to the sample for density measurement for the rectangular flat plate type sputtering target and for 36 blocks for the cylindrical type sputtering target. -GP) using a four-probe method. The measurement was performed at a temperature of 23 ± 5 ° C. and a humidity of 50 ± 20%.
Then, similarly to the density, the variation of the specific resistance in the target sputtering surface and the variation of the specific resistance in the thickness direction were calculated.
Table 2 shows the average value of the specific resistance.

(Abnormal discharge)
The obtained oxide sputtering target was soldered to a backing plate or a backing tube using In solder, and then mounted on a magnetron sputtering device. Then, using a magnetron sputtering apparatus, an Ar gas was used as a sputtering gas, a flow rate was set to 50 sccm, a pressure was set to 0.67 Pa, and an input power of 5 W / cm ² was used to perform sputtering for 1 hour. The number of abnormal discharges was measured by the arc count function.
In this example, RPG-50 (manufactured by mks) was used as the power supply device. The number of abnormal discharges during 1 hour from the start of sputtering is defined as “initial”, and the number of abnormal discharges during 1 hour from the time when the depth of the deepest portion of the erosion portion reaches 5 mm is defined as “final”. In Table 2.

In Comparative Example 1, which was held at 1000 ° C. for 5 hours in the sintering process, the variation in the density in the target sputtering surface, the variation in the density in the thickness direction, and the variation in the specific resistance in the thickness direction were large. The number has increased.
In Comparative Example 2, which was held at 1450 ° C. for 5 hours in the sintering step, the density variation in the target sputtering surface, the density variation in the thickness direction, the specific resistance variation in the target sputtering surface, and the ratio in the thickness direction The variation in resistance was large, and the number of abnormal discharges at the end increased.
In Comparative Example 3 held at 1300 ° C. for 1 hour in the sintering process, the variation in density, the variation in density in the thickness direction, and the variation in specific resistance in the thickness direction in the target sputtering surface were large, and abnormal discharge at the end The number has increased.

  On the other hand, in Example 1-12 of the present invention in which the temperature was kept in the temperature range of 1200 ° C. to 1400 ° C. for 3 hours or more in the sintering step, the density variation in the target sputtering surface and the density variation in the thickness direction were observed. In addition, the dispersion of the specific resistance in the target sputtering surface and the dispersion of the specific resistance in the thickness direction were small, the number of abnormal discharges was small, and the sputtering film could be stably formed.

  From the above, according to the example of the present invention, an oxide sputtering target capable of stably forming a sputter film even when the target sputtering surface is relatively large, and a method for manufacturing this oxide sputtering target It was confirmed that it could be provided.

Claims (5)

As a metal component, zirconium, an oxide sputtering target composed of an oxide containing silicon and indium,
An oxide sputtering target, wherein the variation in density in the target sputtering surface is within 3% and the variation in density in the thickness direction is within 5%.   2. The oxide sputtering target according to claim 1, wherein a variation in resistivity in a target sputtering surface is within 10%, and a variation in resistivity in a thickness direction is within 10%. 3. 3. The oxide sputtering target according to claim 1, wherein the area of the target sputtering surface is 0.02 m ² or more. 4. As a metal component, zirconium, a method for producing an oxide sputtering target consisting of an oxide containing silicon and indium,
A sintering material powder forming step of obtaining a sintering material powder obtained by mixing zirconium oxide powder, silicon oxide powder and indium oxide powder, and a sintering step of sintering the obtained sintering material powder to obtain a sintered body; , And
In the sintering step, the oxide is heated while introducing oxygen, held at a temperature in a range of 1200 ° C. to 1400 ° C. for 3 hours or more, and then heated to a temperature exceeding 1400 ° C. and held. A method for manufacturing a sputtering target.   The method for producing an oxide sputtering target according to claim 4, wherein a median diameter (D50) of the sintering raw material powder is in a range of 0.05 µm to 1.2 µm.