CN114616218A

CN114616218A - Oxide sputtering target and method for producing oxide sputtering target

Info

Publication number: CN114616218A
Application number: CN202080075120.1A
Authority: CN
Inventors: 陆田雄也; 梅本启太
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2019-12-02
Filing date: 2020-11-26
Publication date: 2022-06-10
Also published as: KR20220110169A; JP2021088730A; TW202126838A; WO2021111970A1

Abstract

The present invention provides an oxide sputtering target composed of an oxide containing zirconium, silicon and indium as metal components, wherein the maximum particle diameter of a zirconia phase (11) is 10 [ mu ] m or less.

Description

Oxide sputtering target and method for producing oxide sputtering target

Technical Field

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

The present application claims priority based on patent application No. 2019-217933, filed in japan on 12/2/2019, the contents of which are incorporated herein by reference.

Background

Oxide films containing zirconium, silicon, and indium as metal components have high resistance, and are used as shielding layers for preventing failures due to electrification of liquid crystal elements, organic EL elements, and the like in display panels such as liquid crystal displays, organic EL (Electro Luminescence) displays, and touch panels.

Here, when the shield layer is applied to an in-cell touch panel, the shield layer is also required to function to allow a touch signal to reach a sensor portion inside the panel while eliminating noise from the outside. In addition, the shielding layer is also required to have high transmittance of visible light in order to ensure visibility of the display panel.

The oxide film containing zirconium, silicon, and indium as metal components is also used as a dielectric layer or a protective film of a phase-change optical disc used as an information recording medium.

Here, patent documents 1 to 4 propose an oxide sputtering target used for forming an oxide film containing zirconium, silicon, and indium as metal components.

Recently, it has been required to form an oxide film containing zirconium, silicon, and indium as metal components over a large area with high productivity. Therefore, it is necessary to cope with the increase in size of the sputtering target and the increase in output during sputtering film formation.

However, in an oxide sputtering target containing zirconium, silicon, and indium as metal components, cracks are likely to occur when sputter deposition is performed at a high output, and it is sometimes impossible to stably perform sputter deposition. In particular, in a large sputtering target, cracks tend to easily occur.

Patent document 1: japanese patent laid-open publication No. 2013-142194

Patent document 2: japanese patent laid-open publication No. 2007-327103

Patent document 3: japanese laid-open patent publication No. 2009-062585

Patent document 4: japanese patent laid-open publication No. 2018-040032

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide an oxide sputtering target which can suppress the occurrence of cracks and can perform sputtering deposition stably and with high production efficiency even when sputtering deposition is performed with high output, and a method for manufacturing the oxide sputtering target.

As a result of intensive studies to solve the above problems, the present inventors have confirmed that a zirconia phase exists in an oxide sputtering target containing zirconium, silicon and indium as metal components, the zirconia phase is transformed at around 1000 ℃, and cracks are generated due to a volume change at this time.

Further, it is known that when zirconia powder, which is a raw material of the oxide sputtering target, is pulverized and mixed together with indium oxide powder and silicon oxide powder, the particle size of the zirconia powder is larger than those of the indium oxide powder and the silicon oxide powder, and a coarse zirconia phase is formed, which causes the occurrence of cracks.

The present invention has been made in view of the above-mentioned findings, and an oxide sputtering target according to an embodiment of the present invention is an oxide sputtering target composed of an oxide containing zirconium, silicon, and indium as metal components, and is characterized in that the maximum particle diameter of a zirconia phase is 10 μm or less.

According to the oxide sputtering target of one aspect of the present invention, since the oxide sputtering target is an oxide containing zirconium, silicon, and indium as metal components, an oxide film having high electrical resistance and excellent visible light transmittance can be formed.

Further, since the maximum particle diameter of the zirconia phase is limited to 10 μm or less, when sputtering deposition is performed at a high output, the occurrence of cracks can be suppressed even if the zirconia phase changes in phase and changes in volume. Further, even when the sputtering target is made larger, the occurrence of cracks during sputtering can be suppressed. Therefore, sputtering deposition can be performed stably and with high productivity.

In the oxide sputtering target according to one aspect of the present invention, the average particle diameter of the zirconia phase is D_ZrOD represents the average particle diameter of the other oxide phase_MOIn the case of (2), it is preferable that 0.6. ltoreq. D is satisfied_MO/D_ZrO≤1.8。

In this case, the difference in particle size between the zirconia phase and the other oxide phase is reduced, and the strength of the target can be ensured. Therefore, the occurrence of cracks can be further suppressed when sputter film deposition is performed at a high output.

In the oxide sputtering target according to one aspect of the present invention, the maximum particle diameter is preferably 7 μm or less and the average particle diameter is preferably 4 μm or less in the entire target structure.

In this case, since the particle diameter is made uniform and finer throughout the entire target structure, sputtering film formation can be performed uniformly. Further, the strength of the target can be ensured, and the occurrence of cracks can be further suppressed when sputter film deposition is performed at a high output.

A method for producing an oxide sputtering target according to one aspect 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, the method including: a preliminary pulverization step of pulverizing zirconia powder to a maximum particle diameter of 4 μm or less; a sintering raw material powder forming step of obtaining a sintering raw material powder in which a zirconia powder having a maximum particle diameter of 4 μm or less, a silica powder, and an indium oxide powder are mixed; and a sintering step of heating and sintering the obtained sintering raw material powder while introducing oxygen to obtain a sintered body.

The method for producing an oxide sputtering target having this structure includes a preliminary grinding step of grinding the zirconia powder so that the maximum particle diameter is 4 μm or less. Therefore, the maximum particle size of the zirconia phase after sintering can be suppressed to 10 μm or less.

Thus, an oxide sputtering target can be produced which can suppress the occurrence of cracks when sputter deposition is performed at a high output and can perform sputter deposition stably and with high productivity.

Here, in the method for producing an oxide sputtering target according to one aspect of the present invention, the average particle diameter of the zirconia powder having a maximum particle diameter of 4 μm or less is represented by d_ZrOThe average particle diameter of the indium oxide powder is represented by d_InOThe average particle diameter of the silicon oxide powder is defined as d_SiOIn the case of (2), it is preferable that d is 0.7. ltoreq_InO/d_ZrOD is not less than 1.6 and not less than 0.7_SiO/d_ZrO≤1.6。

In this case, the difference in particle size between the zirconia powder and the indium oxide powder and between the zirconia powder and the silicon oxide powder is small, and thus a high-strength oxide sputtering target can be manufactured.

In the method for producing an oxide sputtering target according to one aspect of the present invention, it is preferable that the maximum particle diameter is 3 μm or less and the average particle diameter is 1 μm or less in all the sintering raw material powders obtained by mixing the zirconia powder, the silica powder, and the indium oxide powder.

In this case, an oxide sputtering target can be produced which has a fine and uniform particle size throughout the target structure and can be uniformly sputter-deposited.

According to an aspect of the present invention, it is possible to provide an oxide sputtering target that can suppress the occurrence of cracks and can perform sputtering film formation stably and with high production efficiency even when sputtering film formation is performed at high output, and a method for manufacturing the oxide sputtering target.

Drawings

Fig. 1 is a photograph showing a structure of an oxide sputtering target according to an embodiment of the present invention.

Fig. 2 is a flowchart showing a method for manufacturing an oxide sputtering target according to an embodiment of the present invention.

Detailed Description

Hereinafter, an oxide sputtering target and a method for manufacturing the oxide sputtering target according to an embodiment of the present invention will be described with reference to the drawings.

The oxide sputtering target according to the present embodiment is used for forming an oxide film suitable as a shield layer provided for antistatic properties or a dielectric layer or a protective film of a phase-change optical disc serving as an information recording medium in a display panel such as a liquid crystal display panel, an organic EL display panel, or a touch panel.

The oxide sputtering target of the present embodiment is not particularly limited in shape, and may be a rectangular flat plate sputtering target having a rectangular sputtering surface or a circular plate sputtering target having a circular sputtering surface. Alternatively, a cylindrical sputtering target having a cylindrical sputtering surface may be used. The area of the sputtering surface is not particularly limited, but is preferably 2.0m in order to efficiently form a film on a large-area substrate²The above large sputtering target.

The oxide sputtering target according to the present embodiment is composed of an oxide containing zirconium, silicon, and indium as metal components.

As shown in fig. 1, the oxide sputtering target has a zirconia phase 11, an indium oxide phase 12, and a composite oxide phase 13 containing at least a part of the above metal elements. In the present embodiment, the composite oxide phase 13 is a composite oxide of In and Si (for example, In)₂Si₂O₇Phase).

In the oxide sputtering target according to the present embodiment, the maximum particle diameter of the zirconia phase 11 is 10 μm or less.

In the present embodiment, the average particle diameter D of the zirconia phase 11_ZrOAnd the average particle diameter D of the indium oxide phase 12 as the other oxide phase_InORatio of D_InO/D_ZrOAnd the average particle diameter D of the zirconia phase 11_ZrOWith the average particle diameter D of the composite oxide phase 13 as the other oxide phase_InSiORatio of D_InSiO/D_ZrOPreferably, each of the amounts is in the range of 0.6 to 1.8.

In the present embodiment, the maximum particle size is preferably 7 μm or less and the average particle size is preferably 4 μm or less in the entire target tissue.

The reasons why the composition of the oxide, the maximum particle size of the zirconia phase 11, the average particle size ratio between the zirconia phase 11 and the other oxide phases (the indium oxide phase 12 and the composite oxide phase 13), and the maximum particle size and the average particle size of the entire target structure are defined as described above in the oxide sputtering target of the present embodiment will be described below.

(oxide composition)

The oxide sputtering target of the present embodiment is composed of an oxide containing zirconium, silicon, and indium as metal components. In the oxide sputtering target having such a composition, an oxide film having a sufficiently high resistance value and excellent visible light transmittance can be formed.

Here, In the present embodiment, when the total amount of the metal components is 100 mass%, it is preferable that the Zr content is In the range of 2 mass% or more and 27 mass% or less, the In content is In the range of 65 mass% or more and 95 mass% or less, the Si content is In the range of 0.5 mass% or more and 15 mass% or less, and the balance is unavoidable impurity metal elements (unavoidable metals). The total content of Zr, In, and Si is preferably 95 mass% or more, and more preferably 99 mass% or more.

Specifically, the oxide sputtering target of the present embodiment is composed of an oxide composed of a metal component and oxygen and unavoidable impurities, and preferably, the metal component contains Zr: 2 to 27 mass% In: 65% by mass or more and 95% by mass or less, and Si: 0.5 to 15 mass%, with the balance being unavoidable metals.

Unavoidable impurities are elements other than oxygen and metal components. The inevitable metals are metal elements other than the elements specifically specified in the above contents.

The chemical property of Hf is similar to that of Zr, and the Hf and Zr are difficult to separate. Thus, ZrO in industrial materials₂Inevitable inclusion of HfO in the powder₂. Thus, Hf is an inevitable metal. The content of Hf is 0 to 0.9 mass%. The inevitable metals include Fe, Ti and Na, and the total amount of these metals is 0 mass% or more and 0.1 mass% or less.

When the Zr content is 2 mass% or more, the durability of the formed oxide film can be improved, and the hardness becomes high, resulting in scratch resistance. On the other hand, when the Zr content is 27 mass% or less, the increase in refractive index can be suppressed, and the occurrence of unnecessary reflection can be suppressed, so that the decrease in visible light transmittance can be suppressed.

The lower limit of the Zr content is preferably 3 mass% or more, and more preferably 5 mass% or more, assuming that the total amount of the metal components is 100 mass%. The upper limit of the Zr content is preferably 21 mass% or less, and more preferably 20 mass% or less.

When the In content is 65 mass% or more, the conductivity of the oxide sputtering target can be ensured, and an oxide film can be stably formed by Direct Current (DC) sputtering. On the other hand, when the In content is 95 mass% or less, the transmittance at short wavelengths can be suppressed from decreasing, and the visibility can be ensured.

The lower limit of the In content is preferably 75% by mass or more, and more preferably 80% by mass or more, assuming that the total amount of the metal components is 100% by mass. The upper limit of the In content is preferably 90% by 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 cracking resistance of the film can be improved. On the other hand, when the Si content is 15 mass% or less, the decrease in the conductivity of the film can be suppressed, and an oxide film can be stably formed by Direct Current (DC) sputtering.

The lower limit of the Si content is preferably 2 mass% or more, and more preferably 3 mass% or less, assuming that the total amount of the metal components is 100 mass%. The upper limit of the Si content is preferably 12 mass% or more, and more preferably 7 mass% or less.

(maximum particle diameter of zirconia phase 11)

In the zirconia phase 11, a phase change occurs at around 1000 ℃ and the volume changes. Therefore, when the coarse zirconia phase 11 is present, a large volume change may occur due to phase change when sputter deposition is performed at a high output, and cracks may occur.

Therefore, in the present embodiment, the maximum particle size of the zirconia phase 11 is limited to 10 μm or less.

In order to further suppress the occurrence of cracks in the oxide sputtering target, the maximum particle size of the zirconia phase 11 is preferably 8 μm or less, and more preferably 7 μm or less.

(average particle size ratio of zirconia phase 11 to other oxide phases)

In the oxide sputtering target of the present embodiment, by reducing the difference in particle size between the zirconia phase 11 and the other oxide phases (the indium oxide phase 12 and the composite oxide phase 13), the strength of the oxide sputtering target can be increased, and the occurrence of cracks can be further suppressed.

Therefore, in the present embodiment, the average particle diameter D of the zirconia phase 11 is set to_ZrOAnd the average particle diameter D of the indium oxide phase 12 as the other oxide phase_InORatio of D_InO/D_ZrOAnd the average particle diameter D of the zirconia phase 11_ZrOWith the average particle diameter D of the composite oxide phase 13 as the other oxide phase_InSiORatio of D_InSiO/D_ZrOPreferably, each of the amounts is in the range of 0.6 to 1.8.

In addition, D_InO/D_ZrOAnd D_InSiO/D_ZrOThe lower limit of (b) is more preferably 0.63 or more, and still more preferably 0.65 or more. On the other hand, D_InO/D_ZrOAnd D_InSiO/D_ZrOThe upper limit of (d) is more preferably 1.75 or less, and still more preferably 1.7 or less.

(maximum particle diameter and average particle diameter of the entire target Structure)

In the oxide sputtering target of the present embodiment, by making the particle diameter finer and more uniform throughout the entire target structure, it is possible to uniformly perform sputtering film formation, and to secure the target strength, and it is possible to further suppress the occurrence of cracks when sputtering film formation is performed at a high output.

Therefore, in the present embodiment, the maximum particle size is preferably 7 μm or less and the average particle size is preferably 4 μm or less in the entire target tissue.

The maximum particle size in the entire target tissue is more preferably 6.5 μm or less, and still more preferably 6 μm or less. Further, the average particle diameter of the entire target tissue is more preferably 3 μm or less, and still more preferably 2 μm or less.

Next, a method for producing the oxide sputtering target of the present embodiment will be described with reference to fig. 2.

(preliminary grinding step S01)

First, zirconia powder (ZrO) is prepared₂Powder). Here, the zirconia powder is free of Fe₂O₃、SiO₂、TiO₂、Na₂The purity of impurities other than unavoidable impurities such as O is preferably 99.9% by mass or more. In addition, ZrO₂And HfO₂Has very strong bonding force even for high-purity ZrO₂The powder may also contain up to 2.5 mass% hafnium oxide (HfO) in unavoidable impurities₂). Thus, in general, ZrO₂Is measured except for HfO₂The content of impurities other than the above was calculated by a difference method using the total amount of the obtained impurities. ZrO of the above₂The purity of the powder was determined as Fe as an impurity₂O₃、SiO₂、TiO₂And Na₂The content of O was calculated by subtracting the total content of these compounds from 100 mass%.

The zirconia powder (ZrO)₂Powder) is pulverized to have a maximum particle diameter of 4 μm or less. The pulverization method is not particularly limited, and may be appropriately selected from conventional pulverization methods.

(sintering raw material powder Forming Process S02)

Next, a silicon oxide powder (SiO) was prepared₂Powder) and indium oxide powder (In)₂O₃Powder). Here, silicon oxide powder (SiO)₂Powder) and indium oxide powder (In)₂O₃Powder) is preferably 99.9% by mass or more, respectively.

These silicon oxide powders (SiO)₂Powder) and indium oxide powder (In)₂O₃Powder), zirconia powder (ZrO) having a maximum particle diameter of 4 μm or less by preliminary pulverization₂Powder) was weighed so as to have a predetermined composition ratio. Pulverizing and mixing the weighed raw material powder by using a wet pulverizing and mixing device to form a sintering raw materialPowder (raw material powder for sintering). Here, examples of the solvent include water.

The method for drying the slurry obtained by pulverizing and mixing is not particularly limited, and can be carried out by a general dryer, a spray dryer, or the like. From the viewpoint of obtaining a homogeneously mixed powder, a spray dryer is preferably used.

Here, among the raw material powders for sintering, zirconia powder (ZrO) having a maximum particle size of 4 μm or less in the preliminary grinding step S01₂Powder) has an average particle diameter of d_ZrOAnd mixing indium oxide powder (In)₂O₃Powder) has an average particle diameter of d_InOSilicon oxide powder (SiO)₂Powder) has an average particle diameter of d_SiOIn the case of (2), it is preferable that d is 0.7. ltoreq_InO/d_ZrOD is not less than 1.6 and not less than 0.7_SiO/d_ZrO≤1.6。

Further, the above average particle diameter ratio d_InO/d_ZrOAnd d_SiO/d_ZrOThe lower limit of (b) is more preferably 0.7 or more, and still more preferably 0.75 or more. And the above average particle diameter ratio d_InO/d_ZrOAnd d_SiO/d_ZrOThe upper limit of (d) is more preferably 1.55 or less, and still more preferably 1.5 or less.

In addition, it is preferable that the maximum particle diameter is 3 μm or less and the average particle diameter is 1 μm or less in the entire sintering material powder obtained.

The maximum particle diameter in the entire sintering material powder is more preferably 2.8 μm or less, and still more preferably 2.6 μm or less. The average particle size in the entire sintering material powder is more preferably 0.9 μm or less, and still more preferably 0.8 μm or less.

(Molding step S03)

Next, the obtained sintering material powder is filled in a molding die and pressurized, thereby obtaining a molded body having a predetermined shape. The pressure at this time is preferably in the range of 20MPa or more and 35MPa or less. The temperature may be normal temperature, but it is preferable to perform press molding at a temperature in the range of 900 ℃ to 950 ℃. This promotes the formation of a sintering neck, and improves the strength of the molded article.

(sintering step S04)

The molded body was charged into a firing apparatus having an oxygen introducing function, and heated and fired while introducing oxygen, thereby obtaining a sintered body.

In this case, the amount of oxygen introduced is preferably in the range of 3L/min to 10L/min. The temperature increase rate is preferably in the range of 50 ℃/h to 200 ℃/h.

The firing step S04 preferably includes a holding step and a main firing step. First, the molded article is preferably held at a temperature of 1200 ℃ to 1400 ℃ for 3 to 5 hours (holding step). Then, the molded body is preferably kept at 1450 ℃ to 1600 ℃ for 5 to 10 hours (main firing step).

In the holding step, when the temperature is lower than 1200 ℃ or the heating time is less than 3 hours, the generation of the composite oxide is insufficient, and there is a possibility that cracks are generated in the main firing step. In the holding step, when the temperature exceeds 1400 ℃ or when the heating time exceeds 5 hours, warpage may occur in the sintered body.

In the main firing step, when the temperature is lower than 1450 ℃, or when the heating time is less than 5 hours, the density of the sintered body may decrease. In the main firing step, when the temperature exceeds 1600 ℃ or when the heating time exceeds 10 hours, the particles may grow excessively.

(machining operation S05)

Next, the sintered body is machined by lathe machining or the like to obtain an oxide sputtering target having a predetermined size.

The oxide sputtering target of the present embodiment is manufactured through the above-described steps.

According to the oxide sputtering target of the present embodiment configured as described above, since it is composed of an oxide containing zirconium, silicon, and indium as metal components, an oxide film having a high resistance value and excellent visible light transmittance can be formed.

Since the maximum particle size of the zirconia phase 11 is limited to 10 μm or less, the occurrence of cracks can be suppressed even when the zirconia phase 11 changes in phase and changes in volume when sputter deposition is performed at a high output. Therefore, sputtering deposition can be performed stably and with high productivity.

In the present embodiment, the average particle diameter D of the zirconia phase 11_ZrOAnd the average particle diameter D of the indium oxide phase 12 as the other oxide phase_InORatio of D_InO/D_ZrOAnd the average particle diameter D of the zirconia phase 11_ZrOWith the average particle diameter D of the composite oxide phase 13 as the other oxide phase_InSiORatio of D_InSiO/D_ZrOIn the range of 0.6 to 1.8, the difference in particle size between the zirconia phase 11 and the indium oxide phase 12 and the composite oxide phase 13, which are other oxide phases, is reduced, and the strength of the target can be ensured. Therefore, the occurrence of cracks can be further suppressed when sputter film deposition is performed at a high output.

In the present embodiment, when the maximum particle diameter is 7 μm or less and the average particle diameter is 4 μm or less in the entire target structure, the particle diameter is made uniform and finer in the entire target structure, and thus sputtering film formation can be performed uniformly. Furthermore, the strength of the target can be ensured, and the occurrence of cracks during sputter film formation at high output can be further suppressed.

Further, according to the method of manufacturing an oxide sputtering target of the present embodiment, since the preliminary grinding step S01 is provided in which the zirconia powder is ground so that the maximum particle size is 4 μm or less, the maximum particle size of the zirconia phase 11 after sintering can be suppressed to 10 μm or less.

Thus, an oxide sputtering target can be produced which can suppress the occurrence of cracks when sputter deposition is performed at a high output and can perform sputter deposition stably and with high production efficiency.

In the present embodiment, the average particle diameter of the zirconia powder having a maximum particle diameter of 4 μm or less is defined as d_ZrOThe average particle diameter of the indium oxide powder is represented by d_InOThe average particle diameter of the silicon oxide powder is defined as d_SiOIn the case of (1), d is 0.7. ltoreq_InO/d_ZrOD is not less than 1.6 and not less than 0.7_SiO/d_ZrOIn this case, the difference in particle size between the zirconia powder and the indium oxide powder and between the zirconia powder and the silica powder is small, and a high-strength oxide sputtering target can be produced.

In the present embodiment, in the case where the maximum particle diameter is 3 μm or less and the average particle diameter is 1 μm or less among all the sintering material powders obtained by mixing the zirconia powder, the silica powder, and the indium oxide powder, it is possible to manufacture an oxide sputtering target which has a fine and uniform particle diameter in the entire target structure and which can be uniformly sputter-formed.

Although the embodiments of the present invention have been described above, the present invention is not limited to these, and modifications may be made as appropriate without departing from the scope of the technical requirements of the present invention.

Examples

The following describes the results of a confirmation experiment performed to confirm the effectiveness of the present embodiment.

< oxide sputtering target >

Indium oxide powder (In) was prepared as a raw material powder₂O₃Powder: purity of 99.9% by mass or more, average particle diameter of 1 μm), and silicon oxide powder (SiO)₂Powder: purity of 99.8% by mass or more, average particle diameter of 2 μm), and zirconium oxide powder (ZrO 2)₂Powder: purity of 99.9 mass% or more and average particle diameter of 2 μm). Then, these were weighed in the mixing ratios shown in table 1. In addition, the purity of the zirconia powder was measured as Fe₂O₃、SiO₂、TiO₂、Na₂O and the like other than HfO₂The content of impurities other than these was calculated by subtracting the total content of these compounds from 100 mass%. The zirconia powder contains HfO in an amount of 2.5 mass% or less₂。

As the preliminary grinding step, the zirconia powder was wet-ground using a bead mill using zirconia balls having a diameter of 0.5mm as a grinding medium under the conditions shown in table 1.

The maximum particle diameter and median diameter (D50) of the pulverized zirconia powder were measured by a laser diffraction scattering method.

Specifically, 100mL of an aqueous solution having a sodium hexametaphosphate concentration of 0.2 mol% was prepared, 10mg of zirconia powder was added to the aqueous solution, and the particle size distribution was measured by a laser diffraction scattering method (measuring apparatus: Nikkiso Co., Ltd., Microtrac MT 3000). A cumulative particle size distribution curve was prepared from the obtained particle size distribution, and the maximum particle size and the average particle size (median diameter D50) were obtained.

Here, the median diameter (D50) represents a particle diameter at which the cumulative volume is 50%.

As shown in table 1, each raw material powder of the pulverized zirconia powder, indium oxide powder, and silica powder was wet-pulverized and mixed for 60 minutes using a basket pulverizer apparatus using zirconia balls having a diameter of 2mm as a pulverizing medium, or a bead mill apparatus using zirconia balls having a diameter of 0.5mm as a pulverizing medium.

The obtained slurry was dried using a dryer to obtain a sintering raw material powder. The maximum particle diameter and the average particle diameter (median diameter (D50)) of the obtained sintering material powder are shown in table 1. The measurement method was the same as in the case of the zirconia powder.

The average particle diameter ratio of the zirconia powder, the indium oxide powder and the silica powder was measured. The measurement results are shown in table 1.

As for the sintering material powder, three COMPO images (reflection electron composition images) at a magnification of 3000 times were picked up using an Electron Probe Microanalyzer (EPMA) apparatus, and the average particle diameters of the zirconia powder, the indium oxide powder and the silica powder were obtained by image analysis to calculate the average particle diameter ratio. Specifically, the equivalent circle diameter (particle area S ═ pi D) was measured as the particle diameter of each particle²D of/4). The average value of the circle-equivalent diameters of the particles was calculated as the average particle diameter.

Then, in inventive examples 1 to 6, 10 to 12 and comparative example 1, the obtained sintering material powder was press-molded to obtain a rectangular flat plate-shaped molded body. The dimensions of the molding were 165mm × 298 mm. The pressure was set to 98 MPa.

In inventive examples 7 to 9 and comparative example 2, the obtained sintering material powder was subjected to CIP (cold isostatic pressing) to obtain a cylindrical molded body. The dimensions of the molding die were 205mm in outside diameter, 165mm in inside diameter, and 200mm in height. The pressure was set to 98 MPa.

Then, the obtained molded article was charged into a firing apparatus having an oxygen introducing function (inner volume of the apparatus 27000 cm)³) While oxygen is introduced, the mixture is heated and sintered. At this time, the amount of oxygen introduced was set to 6L/min. The temperature increase rate was set at 120 ℃/h.

Then, at the time of raising the sintering temperature, the temperature was maintained under the conditions described in item "maintenance" shown in table 2. Next, the sintered body was obtained by performing main firing under the conditions described in the item "main firing" shown in table 2.

The sintered bodies thus obtained were machined to obtain rectangular flat plate sputtering targets 126mm × 178mm × 6mm thick in inventive examples 1 to 6, 10 to 12 and comparative example 1. In inventive examples 7 to 9 and comparative example 2, cylindrical sputtering targets having an outer diameter of 155mm, an inner diameter of 135mm and a height of 150mm were obtained.

In comparative example 3, the obtained sintering material powder was charged into a mold having a diameter of 200mm, and pressurized at a pressure of 15MPa to produce two disk-shaped molded bodies having a diameter of 200mm and a thickness of 10 mm.

The obtained two-piece molded article was charged into an electric furnace (furnace internal volume 27000 cm)³) In the above, oxygen was passed through the electric furnace at a flow rate of 4L per minute, and the furnace was held at the firing temperature shown in table 2 for 7 hours, thereby firing the steel to produce a sintered body. Subsequently, oxygen was continuously circulated in the electric furnace, and the sintered body was cooled to 600 ℃. Then, the flow of oxygen was stopped, and the furnace was cooled to room temperature by cooling. Subsequently, the sintered body was taken out from the electric furnace.

The sintered body thus obtained was machined to obtain two disk-shaped sputtering targets having a diameter of 152.4mm and a thickness of 6 mm.

The following items were evaluated with respect to the obtained oxide sputtering target. The evaluation results are shown in table 2.

(composition of Metal component)

A sample was cut out of the prepared oxide sputtering target, pulverized, and pretreated with an acid. Then, the metal components of Zr, Si, and In were analyzed by ICP-AES (inductively coupled plasma-atomic emission spectroscopy), and the contents of the metal components were calculated from the obtained results.

In addition, in "composition of oxide powder" in Table 1, the description is made for ZrO₂、In₂O₃、SiO₂ZrO when the total amount of (A) is set to 100%₂、In₂O₃、SiO₂The amount of (c). In "metal composition of target" In table 2, amounts of Zr, Si, and In are described assuming that the total amount of Zr, Si, and In is 100%.

(particle diameter of sintered body)

A sample was cut out from the prepared oxide sputtering target, and wet-polishing was performed. Next, a COMPO image at a magnification of 3000 times (30. mu. m.times.40 μm) was taken using an Electron Probe Microanalyzer (EPMA) apparatus. Three images were captured, and each phase (ZrO) for all three images was calculated by image processing based on the captured COMPO images₂Phase, In₂O₃Phase, In₂SiO₇Phase), and the maximum and average grain diameters of the crystal grains of the entire target. The average particle diameter ratio is expressed as In₂O₃Phase or In₂Si₂O₇Average particle size of phase divided by ZrO₂Value of average particle size of the phase.

Here, the particle diameter represents an equivalent circle diameter (crystal grain area S ═ pi D)²D of/4). The average particle diameter is an average value of equivalent circle diameters of crystal grains.

(Density)

In the rectangular flat plate type sputtering target, a sample of 10mm × 10mm cut from the center was measured for the dimensional density.

In the cylindrical sputtering target, a sample of 10mm × 10mm cut from the center in the axial direction was measured for the dimensional density. The measurement results are shown in table 2.

(Strength)

Similarly to the density measurement, measurement samples were collected from the respective sputtering targets, and the three-point bending strength was measured according to JIS R1601. The evaluation results are shown in table 2.

(cracks in sputter deposition)

The sputtering target was welded to a backing plate made of oxygen-free copper and mounted in a magnetron sputtering apparatus (ULVAC, manufactured by inc., SIH-450H). Then, the inside of the sputtering apparatus was evacuated to 5X 10 by a vacuum evacuation apparatus^-5Pa or less. Then, Ar gas and O are introduced₂The gas was subjected to pre-sputtering for 1 hour while adjusting the sputtering gas pressure to 0.67 Pa. Thereby removing the processed layer from the target surface. Ar gas and O at this time₂The gas flow ratio was 47:3 and the power was DC 1200W.

Next, an oxide film was formed on the glass substrate under the same sputtering conditions. Then, the sputtering apparatus was opened to the atmosphere. Then, the sputtering target was taken out from the sputtering apparatus, and the appearance was visually observed to confirm the presence or absence of the occurrence of cracks. The results are shown in table 2.

[ Table 1]

[ Table 2]

In comparative examples 1 to 3, the preliminary grinding step was not performed, and the maximum particle diameter of the zirconia powder was more than 4 μm. In comparative examples 1 to 3, ZrO₂The maximum particle size of each phase exceeds 10 μm, and cracks are generated during sputtering film formation.

On the other hand, in the cases of invention examples 1 to 12, the preliminary grinding step was carried out, and the maximum particle diameter of the zirconia powder was 4 μm or less. In examples 1 to 12 of the present invention, ZrO₂The maximum grain size of the phase is less than 10 μm, no crack is generated during sputtering film formation, and the phase can be stably formedThe film formation is carried out regularly.

In examples 2 to 7 and 9 to 11 of the present invention, the average particle diameter D of the zirconia phase_ZrOWith the average particle diameter D of the indium oxide phase as the other oxide phase_InORatio of D_InO/D_ZrOAnd the average particle diameter D of the zirconia phase_ZrOWith the average particle diameter D of the composite oxide phase as the other oxide phase_InSiORatio of D_InSiO/D_ZrOIn the range of 0.6 to 1.8, respectively, and has a maximum particle diameter of 7 μm or less and an average particle diameter of 4 μm or less in the entire target tissue. In the invention examples 2 to 7 and 9 to 11, the strength of the target was further improved.

As described above, according to the present invention, it has been confirmed that an oxide sputtering target capable of suppressing the generation of cracks and performing sputtering film formation stably and with high production efficiency even when sputtering film formation is performed at high output power, and a method for manufacturing the oxide sputtering target can be provided.

Industrial applicability

The oxide sputtering target of the present embodiment can be preferably applied to a process for producing a barrier layer of a display panel such as a liquid crystal display panel, an organic EL display panel, or a touch panel, or an oxide film containing zirconium, silicon, and indium, which is used as a dielectric layer or a protective film of a phase-change optical disc, by a sputtering method.

Description of the symbols

11-zirconia phase, 12-indium oxide phase, 13-composite oxide phase, S01-preliminary pulverization step, S02-sintering raw material powder formation step, S03-molding step, S04-sintering step, S05-machining step.

Claims

1. An oxide sputtering target composed of an oxide containing zirconium, silicon and indium as metal components, characterized in that,

the maximum particle diameter of the zirconia phase is 10 μm or less.

2. The oxide sputtering target according to claim 1,

the average particle diameter of the zirconia phase is defined as D_ZrOD represents the average particle diameter of the other oxide phase_MOIn the case of (1), D is 0.6. ltoreq_MO/D_ZrO≤1.8。

3. The oxide sputtering target according to claim 1 or 2,

the maximum particle diameter is 7 μm or less and the average particle diameter is 4 μm or less in the entire target tissue.

4. A method for producing an oxide sputtering target composed of an oxide containing zirconium, silicon, and indium as metal components, the method comprising:

a pre-pulverization step of pulverizing zirconia powder to a maximum particle size of 4 μm or less;

a sintering raw material powder forming step of obtaining a sintering raw material powder in which a zirconia powder having a maximum particle diameter of 4 μm or less, a silica powder, and an indium oxide powder are mixed; and

and a sintering step of heating and sintering the obtained sintering raw material powder while introducing oxygen to obtain a sintered body.

5. The method for manufacturing an oxide sputtering target according to claim 4,

the average particle diameter of the zirconia powder is defined as d_ZrOThe average particle diameter of the indium oxide powder is represented by d_InOThe average particle diameter of the silicon oxide powder is defined as d_SiOIn the case of (a) in (b),

d is more than or equal to 0.7_InO/d_ZrOD is not less than 1.6 and not less than 0.7_SiO/d_ZrO≤1.6。

6. The method for manufacturing an oxide sputtering target according to claim 4 or 5,

the sintered powder is obtained by mixing zirconia powder, silica powder and indium oxide powder, and has a maximum particle diameter of 3 μm or less and an average particle diameter of 1 μm or less.