A method for preparing ITO sputtering target

Abstract

The present invention discloses a method for preparing an ITO sputtering target. Indium oxide powder, tin oxide powder, and nano-tin oxide of different particle sizes are prepared into a slurry or sol, ball-milled to obtain an ITO slurry, poured into a mold, and sintered at high temperature in an atmospheric oxygen atmosphere to obtain the ITO sputtering target. The ITO sputtering target prepared by the present invention has good uniformity, high density, and low resistivity, ensuring uniformity and consistency of display screens. Furthermore, the method has the advantages of low cost and high production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of coating materials, and in particular to a method for preparing an ITO sputtering target. Background Art

[0002] Indium tin oxide (ITO) thin films, characterized by high transparency, low resistivity, high mechanical hardness, and excellent chemical stability, are widely used in electronic display applications, such as LCDs, OLEDs, and touchscreens, to achieve high-quality image display. ITO targets, a ceramic material made of indium tin oxide, are the raw material for producing ITO thin films. Currently, ITO thin films are typically produced by vacuum sputtering the target. In the display industry, ITO thin films are a core component of display devices. To ensure high-quality image display, ITO films must exhibit high transparency, surface flatness, and uniformity. The performance of ITO thin films is closely related to the target. To improve the quality and stability of ITO thin films, the target must possess high density and high uniformity. Currently, ITO targets are typically made by mixing indium oxide powder and tin oxide powder in a certain proportion, forming a green body, and then sintering at high temperature. The ITO targets produced by this method suffer from poor uniformity, leading to cracking during the sputtering process and uneven film formation. Summary of the Invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes a method for preparing an ITO sputtering target.

[0004] The present invention provides a method for preparing an ITO sputtering target, comprising the following steps:

[0005] S1. Add indium oxide powder with a D50 of 1.8 to 2.0 μm into water, stir and disperse evenly, then add acetic acid and stir for 10 to 20 minutes, then add ammonia water until the pH is 6 to 8, then add a dispersant and stir and disperse evenly to obtain an indium oxide slurry;

[0006] S2. Add tin oxide powder with a D50 of 1.4 to 1.6 μm into water, stir and disperse evenly, then add acetic acid, stir for 10 to 20 minutes, then add ammonia water until the pH is 6 to 8, and then add a dispersant to obtain a tin oxide slurry;

[0007] S3, adding nano-tin oxide and dispersant into water, and uniformly dispersing by ultrasonication to obtain nano-tin oxide sol;

[0008] S4. The indium oxide slurry is mixed with tin oxide slurry and nano-tin oxide sol and then ball-milled to obtain an ITO slurry; a binder is then added to the ITO slurry and mixed evenly, and after pouring into a mold for forming, the slurry is first degreased at high temperature in an inert atmosphere, and then sintered at high temperature in an oxygen atmosphere at normal pressure to obtain an ITO sputtering target.

[0009] Preferably, in S1, the mass ratio of indium oxide powder, water, acetic acid and dispersant is 40-50:50-60:1-5:2-4.

[0010] Preferably, in S2, the mass ratio of tin oxide powder, water, acetic acid and dispersant is 40-50:50-60:1-5:2-4.

[0011] Preferably, in S3, the mass ratio of nano-tin oxide, dispersant and water is 1-5:2-5:90-97.

[0012] Preferably, the particle size of the nano-tin oxide is 30 to 60 nm.

[0013] Preferably, the mass ratio of the indium oxide powder, the tin oxide powder, and the nano-tin oxide is 90:9.5-9.9:0.1-0.5.

[0014] Preferably, the mass of the binder is 0.2-0.5% of the mass of the ITO slurry.

[0015] Preferably, in S4, the ball milling speed is 200-300 rpm, and the time is 5-8 hours.

[0016] Preferably, the high-temperature sintering is performed at a temperature of 1500-1600° C. and for a time of 4-10 hours.

[0017] Preferably, the dispersant is ammonium polyacrylate, and the binder is polyvinyl alcohol.

[0018] An ITO sputtering target is prepared by the method.

[0019] The beneficial effects of the present invention are as follows:

[0020] The present invention selects indium oxide powder, tin oxide powder, and nano-tin oxide of different particle sizes and mixes them in appropriate proportions. The appropriate gradation is used to improve the density and internal structural uniformity of the target material after sintering. Furthermore, the addition of an appropriate amount of nano-tin oxide is beneficial for improving sintering activity and further enhancing the density of the target material. Acid pretreatment of the indium oxide powder and the tin oxide powder before ball milling can increase the hydroxyl groups on the powder surface, improve the interaction between the powder and the dispersant, and make the ITO slurry system more uniform after ball milling, thereby improving the density and uniformity of the target material after sintering. The preparation method of the present invention improves upon the conventional method of preparing ITO sputtering targets by casting and pressureless sintering. The prepared ITO sputtering target has good uniformity, high density, and low resistivity, can ensure the uniformity and consistency of the display screen, and has the advantages of low cost and high production efficiency. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is described in detail below through specific embodiments.

[0022] Example 1

[0023] A method for preparing an ITO sputtering target comprises the following steps:

[0024] S1. Add 90 parts by mass of indium oxide powder with a D50 of 1.9 μm to 110 parts by mass of water, stir and disperse evenly, then add 6 parts by mass of glacial acetic acid, stir for 15 minutes, then add ammonia water to a pH of 7, and then add 6 parts by mass of ammonium polyacrylate, stir and disperse evenly to obtain an indium oxide slurry;

[0025] S2, 9.8 parts by mass of tin oxide powder with a D50 of 1.5 μm was added to 11.2 parts by mass of water, and the mixture was stirred and dispersed uniformly. Then, 0.6 parts by mass of glacial acetic acid was added and stirred for 15 minutes. Then, aqueous ammonia was added until the pH was 7, and then 0.6 parts by mass of ammonium polyacrylate was added to obtain a tin oxide slurry;

[0026] S3, adding 0.2 parts by mass of nano-tin oxide with a particle size of 50 to 60 nm and 0.3 parts by mass of ammonium polyacrylate to 9.5 parts by mass of water, and uniformly dispersing them by ultrasonication to obtain a nano-tin oxide sol;

[0027] S4. Mix indium oxide slurry, tin oxide slurry and nano-tin oxide sol, and perform ball milling at a rotation speed of 200 rpm for 6 hours to obtain ITO slurry; then add polyvinyl alcohol equivalent to 0.3% of the mass of ITO slurry to the ITO slurry and mix evenly. After pouring into a mold for molding, first degrease at a high temperature of 550°C for 15 hours in an argon atmosphere, and then sinter at a high temperature of 1550°C for 5 hours in an oxygen atmosphere at normal pressure to obtain an ITO sputtering target.

[0028] Example 2

[0029] A method for preparing an ITO sputtering target comprises the following steps:

[0030] S1. Add 90 parts by mass of indium oxide powder with a D50 of 1.9 μm to 135 parts by mass of water, stir and disperse evenly, then add 2.5 parts by mass of glacial acetic acid, stir for 10 minutes, then add ammonia water to a pH of 7, and then add 5 parts by mass of ammonium polyacrylate, stir and disperse evenly to obtain an indium oxide slurry;

[0031] S2, 9.9 parts by mass of tin oxide powder with a D50 of 1.5 μm was added to 14.1 parts by mass of water, and the mixture was stirred and dispersed uniformly. Then, 0.3 parts by mass of glacial acetic acid was added and stirred for 10 minutes. Then, aqueous ammonia was added until the pH was 7, and then 0.5 parts by mass of ammonium polyacrylate was added to obtain a tin oxide slurry;

[0032] S3, adding 0.1 parts by mass of nano-tin oxide with a particle size of 50 to 60 nm and 0.2 parts by mass of ammonium polyacrylate to 9.7 parts by mass of water, and uniformly dispersing them by ultrasonication to obtain a nano-tin oxide sol;

[0033] S4. Mix indium oxide slurry, tin oxide slurry and nano-tin oxide sol, and ball-mill at a rotation speed of 200 rpm for 5 hours to obtain ITO slurry; then add polyvinyl alcohol equivalent to 0.2% of the mass of ITO slurry to the ITO slurry and mix evenly. After pouring into a mold for molding, first degrease at a high temperature of 500°C for 20 hours in an argon atmosphere, and then sinter at a high temperature of 1500°C for 10 hours in an oxygen atmosphere at normal pressure to obtain an ITO sputtering target.

[0034] Example 3

[0035] A method for preparing an ITO sputtering target comprises the following steps:

[0036] S1. Add 90 parts by mass of indium oxide powder with a D50 of 1.9 μm to 90 parts by mass of water, stir and disperse evenly, then add 9 parts by mass of glacial acetic acid, stir for 20 minutes, then add ammonia water to a pH of 6 to 8, and then add 7 parts by mass of ammonium polyacrylate, stir and disperse evenly to obtain an indium oxide slurry;

[0037] S2, 9.5 parts by mass of tin oxide powder with a D50 of 1.5 μm was added to 9.5 parts by mass of water, stirred and dispersed uniformly, and then 0.95 parts by mass of glacial acetic acid was added and stirred for 10 minutes, and then ammonia water was added to a pH of 7, and then 0.65 parts by mass of ammonium polyacrylate was added to obtain a tin oxide slurry;

[0038] S3, adding 0.5 parts by mass of nano-tin oxide with a particle size of 50 to 60 nm and 0.5 parts by mass of ammonium polyacrylate to 9 parts by mass of water, and uniformly dispersing them by ultrasonication to obtain a nano-tin oxide sol;

[0039] S4. Mix indium oxide slurry, tin oxide slurry and nano-tin oxide sol, and perform ball milling at a rotation speed of 300 rpm for 8 hours to obtain ITO slurry; then add polyvinyl alcohol equivalent to 0.5% of the mass of ITO slurry to the ITO slurry and mix evenly. After pouring into a mold for molding, first degrease at a high temperature of 600°C for 10 hours in an argon atmosphere, and then sinter at a high temperature of 1600°C for 4 hours in an oxygen atmosphere at normal pressure to obtain an ITO sputtering target.

[0040] Comparative Example 1

[0041] A method for preparing an ITO sputtering target comprises the following steps:

[0042] 90 parts by mass of indium oxide powder with a D50 of 1.9 μm, 9.8 parts by mass of tin oxide powder with a D50 of 1.5 μm, 0.2 parts by mass of nano-tin oxide with a particle size of 50 to 60 nm, and 7 parts by mass of ammonium polyacrylate are added to 130 parts by mass of water, mixed evenly, and then ball-milled at a rotation speed of 200 rpm for 6 hours to obtain an ITO slurry; then, polyvinyl alcohol equivalent to 0.3% by mass of the ITO slurry is added to the ITO slurry and mixed evenly, poured into a mold for molding, first degreased at 550° C. for 15 hours in an argon atmosphere, and then sintered at 1550° C. for 5 hours in an oxygen atmosphere at normal pressure to obtain an ITO sputtering target.

[0043] Comparative Example 2

[0044] A method for preparing an ITO sputtering target comprises the following steps:

[0045] S1. Add 90 parts by mass of indium oxide powder with a D50 of 1.9 μm to 110 parts by mass of water, stir and disperse evenly, then add 6 parts by mass of ammonium polyacrylate, stir and disperse evenly to obtain an indium oxide slurry;

[0046] S2, adding 9.8 parts by mass of tin oxide powder with a D50 of 1.5 μm to 11.2 parts by mass of water, stirring and dispersing the powder evenly, and then adding 0.6 parts by mass of ammonium polyacrylate to obtain a tin oxide slurry;

[0047] S3, adding 0.2 parts by mass of nano-tin oxide with a particle size of 50 to 60 nm and 0.3 parts by mass of ammonium polyacrylate to 9.5 parts by mass of water, and uniformly dispersing them by ultrasonication to obtain a nano-tin oxide sol;

[0048] S4. Mix indium oxide slurry, tin oxide slurry and nano-tin oxide sol, and perform ball milling at a rotation speed of 200 rpm for 6 hours to obtain ITO slurry; then add polyvinyl alcohol equivalent to 0.3% of the mass of ITO slurry to the ITO slurry and mix evenly. After pouring into a mold for molding, first degrease at a high temperature of 550°C for 15 hours in an argon atmosphere, and then sinter at a high temperature of 1550°C for 5 hours in an oxygen atmosphere at normal pressure to obtain an ITO sputtering target.

[0049] Comparative Example 3

[0050] A method for preparing an ITO sputtering target comprises the following steps:

[0051] S1. Add 90 parts by mass of indium oxide powder with a D50 of 1.9 μm to 110 parts by mass of water, stir and disperse evenly, then add 6 parts by mass of glacial acetic acid, stir for 15 minutes, then add ammonia water to a pH of 7, and then add 6 parts by mass of ammonium polyacrylate, stir and disperse evenly to obtain an indium oxide slurry;

[0052] S2, 10 parts by mass of tin oxide powder with a D50 of 1.5 μm was added to 11.2 parts by mass of water, and the mixture was stirred and dispersed uniformly. Then, 0.6 parts by mass of glacial acetic acid was added and stirred for 15 minutes. Then, aqueous ammonia was added until the pH was 7, and then 0.6 parts by mass of ammonium polyacrylate was added to obtain a tin oxide slurry;

[0053] S3. After mixing the indium oxide slurry and the tin oxide slurry, the mixture is ball-milled at a rotation speed of 200 rpm for 6 hours to obtain an ITO slurry; then, polyvinyl alcohol equivalent to 0.3% of the mass of the ITO slurry is added to the ITO slurry and mixed evenly. After pouring into a mold for molding, the mixture is first degreased at a high temperature of 550°C for 15 hours under an argon atmosphere, and then sintered at a high temperature of 1550°C for 5 hours under a normal pressure oxygen atmosphere to obtain an ITO sputtering target.

[0054] Test example

[0055] Five sampling points were randomly selected on the ITO sputtering targets of Example 1 and Comparative Examples 1 to 3, and the relative density and resistivity were tested (the results were averaged). The results are shown in Table 1:

[0056] Table 1

[0057]

[0058] The specific test values ​​and average deviations of the relative density of each sampling point of the ITO sputtering target of Example 1 and Comparative Examples 1 to 3 are shown in Table 2:

[0059] Table 2

[0060]

[0061] Combining Table 1 and Table 2, it can be seen that the ITO sputtering target of the present invention has high density, low resistivity and excellent uniformity.

[0062] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing an ITO sputtering target, characterized in that: The following steps are involved: S1. Add indium oxide powder with a D50 of 1.8 to 2.0 μm into water, stir and disperse it evenly, then add acetic acid and stir for 10 to 20 minutes, then add ammonia water until the pH is 6 to 8, then add a dispersant and stir and disperse it evenly to obtain an indium oxide slurry; the mass ratio of indium oxide powder, water, acetic acid and dispersant is 40 to 50:50 to 60:1 to 5:2 to 4; S2. Add tin oxide powder with a D50 of 1.4 to 1.6 μm into water, stir and disperse evenly, then add acetic acid, stir for 10 to 20 minutes, then add ammonia water until the pH is 6 to 8, and then add a dispersant to obtain a tin oxide slurry; the mass ratio of tin oxide powder, water, acetic acid and dispersant is 40 to 50:50 to 60:1 to 5:2 to 4; S3, adding nano-tin oxide and a dispersant into water, and uniformly dispersing them by ultrasonication to obtain a nano-tin oxide sol; wherein the particle size of the nano-tin oxide is 30 to 60 nm; S4. The indium oxide slurry is mixed with tin oxide slurry and nano-tin oxide sol and then ball-milled to obtain ITO slurry, wherein the mass ratio of the indium oxide powder, tin oxide powder and nano-tin oxide is 90:9.5-9.9:0.1-0.5; then a binder is added to the ITO slurry and mixed evenly, and after pouring into a mold for forming, it is first degreased at high temperature in an inert atmosphere, and then sintered at high temperature in an oxygen atmosphere at normal pressure to obtain an ITO sputtering target; the high-temperature sintering temperature is 1500-1600°C, and the time is 4-10 hours.

2. The method for preparing an ITO sputtering target according to claim 1, wherein In S3, the mass ratio of nano-tin oxide, dispersant and water is 1-5:2-5:90-97.

3. The method for preparing an ITO sputtering target according to claim 1, wherein The mass of the binder is 0.2-0.5% of the mass of the ITO slurry.

4. The method for preparing an ITO sputtering target according to claim 1, wherein In S4, the ball milling speed is 200-300 rpm, and the time is 5-8 hours.

5. The method for preparing an ITO sputtering target according to claim 1, wherein: The dispersant is ammonium polyacrylate, and the binder is polyvinyl alcohol.

6. An ITO sputtering target, characterized in that: Prepared by the method according to any one of claims 1 to 5.

Images